Cell cycle progression is regulated by interactions between cyclins and cyclin-dependent kinases (CDKs). p21(WAF1) is one of the CIP/KIP family which inhibits CDKs activity. Increased expression of p21(WAF1) may play ...Cell cycle progression is regulated by interactions between cyclins and cyclin-dependent kinases (CDKs). p21(WAF1) is one of the CIP/KIP family which inhibits CDKs activity. Increased expression of p21(WAF1) may play an important role in the growth arrest induced in transformed cells. Although the stability of the p21( WAF1) mRNA could be altered by different signals, cell differentiation and numerous influencing factors. However, recent studies suggest that two known mechanisms of epigenesis, i.e.gene inactivation by methylation in promoter region and changes to an inactive chromatin by histone deacetylation, seem to be the best candidate mechanisms for inactivation of p21( WAF1). To date, almost no coding region p21(WAF1) mutations have been found in tumor cells, despite extensive screening of hundreds of various tumors. Hypermethylation of the p21(WAF1) promoter region may represent an alternative mechanism by which the p21(WAF1/CIP1) gene can be inactivated. The reduction of cellular DNMT protein levels also induces a corresponding rapid increase in the cell cycle regulator p21(WAF1) protein demonstrating a regulatory link between DNMT and p21(WAF1) which is independent of methylation of DNA. Both histone hyperacetylation and hypoacetylation appear to be important in the carcinoma process, and induction of the p21(WAF1) gene by histone hyperacetylation may be a mechanism by which dietary fiber prevents carcinogenesis. Here, we review the influence of histone acetylation and DNA methylation on p21(WAF1) transcription, and affection of pathways or factors associated such as p 53, E2A, Sp1 as well as several histone deacetylation inhibitors.展开更多
AIM: To study the expression and serum level of HBxAg,Fas and FasL in tissues of HCC patients, and to assess the relationship between HBxAg and Fas/FasL system.METHODS: Tissues from 50 patients with HCC were tested fo...AIM: To study the expression and serum level of HBxAg,Fas and FasL in tissues of HCC patients, and to assess the relationship between HBxAg and Fas/FasL system.METHODS: Tissues from 50 patients with HCC were tested for the expression of HBxAg, Fas and FasL by S-P immunohistochemistry. Serum levels of sFas/sFasL and HBsAg/HBeAg were measured by ELISA assay. HBV X gene was detected by PCR in serum and confirmed by automatic sequencing. Fifty cases of liver cirrhosis and 30 normal controls were involved in serum analysis.RESULTS: The expression of HBxAg, Fas and FasL in carcinoma tissues was 96 %, 84 % and 98 %, respectively.Staining of HBxAg, Fas and FasL was observed predominately in cytoplasms, no significant difference was found in intensity between HBxAg, Fas and FasL (P＞0.05). HBxAg, Fas and FasL might express in the same area of carcinoma tissues and this co-expression could be found in most patients with HCC. The mean levels of sFas in serum from HCC, cirrhosis and normal controls were 762.29±391.56 μg@ L-1 835.36±407.33 μg@L-1 and 238.27±135.29 μg@L-1. The mean levels of sFasL in serum from HCC, cirrhosis and normal controls were 156.36±9.61iμg@ L-1, 173.63±18.74 μg@L-1 and 121.96±7.83 μg@ L-1.Statistical analysis showed that both sFas and sFasL in HCC and cirrhosis patients were significantly higher than those in normal controls (P＜0.01). Serum HBV X gene was found in 32 % of HCC patients and ,46 % of cirrhotic patients.There was no significant relationship between serum level of sFas/sFasL and serum X gene detection (P＞0.05). Eight percent of HCC patients with negative HBsAg and HBeAg in serum might have X gene in serum and HBxAg expression in carcinoma tissues.CONCLUSION: Our data suggest that HBxAg and Fas/FasL system plays an important role in the development of human HCC. Expression of HBxAg can leads to expression of Fas/FasL system which and reverse apoptosis of hepatocellular carcinoma induced by FasL.展开更多
AIM: To analyze the risk factors for pancreatic leakage after pancreaticoduodenectomy (PD) and to evaluate whether duct-to-mucosa pancreaticojejunostomy could reduce the risk of pancreatic leakage. METHODS: Sixty-two ...AIM: To analyze the risk factors for pancreatic leakage after pancreaticoduodenectomy (PD) and to evaluate whether duct-to-mucosa pancreaticojejunostomy could reduce the risk of pancreatic leakage. METHODS: Sixty-two patients who underwent PD at our hospital between January 2000 and November 2003 were reviewed retrospectively. The primary diseases of the patients included pancreas cancer, ampullary cancer, bile duct cancer, islet cell cancer, duodenal cancer, chronic pancreatitis, pancreatic cystadenoma, and gastric cancer. Standard PD was performed for 25 cases, PD with extended lymphadenectomy for 27 cases, pylorus-preserving PD for 10 cases. A duct-to-mucosa pancreaticojejunostomy was performed for patients with a hard pancreas and a dilated pancreatic duct, and a traditional end-to-end invagination pancreaticojejunostomy for patients with a soft pancreas and a non-dilated duct. Patients were divided into two groups according to the incidence of postoperative pancreaticojejunal anastomotic leakage: 10 cases with leakage and 52 cases without leakage. Seven preoperative and six intraoperative risk factors with the potential to affect the incidence of pancreatic leakage were analyzed with SPSS10.0 software. Logistic regression was then used to determine the effect of multiple factors on pancreatic leakage. RESULTS: Of the 62 patients, 10 (16.13%) were identified as having pancreatic leakage after operation. Other major postoperative complications included delayed gastric emptying (eight patients), abdominal bleeding (four patients), abdominal abscess (three patients) and wound infection (two patients). The overall surgical morbidity was 43.5% (27/62). The hospital mortality in this series was 4.84% (3/62), and the mortality associated with pancreatic fistula was 10% (1/10). Sixteen cases underwent duct-to-mucosa pancreaticojejunostomy and 1 case (1/16, 6.25%) devel-oped postoperative pancreatic leakage, 46 cases underwent invagination pancreaticojejunostomy and 9 cases (9/46, 19.6%) developed postoperative pancreatic leakage. General risk factors including patient age, gender, history of jaundice, preoperative nutrition, pathological diagnosis and the length of postoperative stay were similar in the two groups. There was no statistical difference in the incidence of pancreatic leakage between the patients who received the prophylactic use of octreotide after surgery and the patients who did not undergo somatostatin therapy. Moreover, multivariate logistic regression analysis showed that none of the above factors seemed to be associated with pancreatic fistula. Two intraoperative risk factors, pancreatic duct size and texture of the remnant pancreas, were found to be significantly associated with pancreatic leakage. The incidence of pancreatic leakage was 4.88% in patients with a pancreatic duct size greater than or equal to 3 mm and was 38.1% in those with ducts smaller than 3 mm (P = 0.002). The pancreatic leakage rate was 2.94% in patients with a hard pancreas and was 32.1% in those with a soft pancreas (P = 0.004). Operative time, blood loss and type of resection were similar in the two patient groups. The incidence of pancreatic leakage was 6.25% (1/16) in patients with duct-to-mucosa anastomosis, and was 19.6% (9/46) in those with traditional invagination anastomosis. Although the difference of pancreatic leakage between the two groups was obvious, no statistical signific-ance was found. This may be due to the small number of patients with duct-to-mucosa anastomosis. By further analyzing with multivariate logistic regression, both pancreatic duct size and texture of the remnant pancreas were demonstrated to be independent risk factors (P= 0.007 and 0.017, OR = 11.87 and 15.45). Although anastomotic technique was not a significant factor, pancreatic leakage rate was much less in cases that underwent duct-to-mucosa pancreaticojejunostomy. CONCLUSION: Pancreatic duct size and texture of the remnant pancreas are risk factors influencing pancreatic leakage after PD. Duct-to-mucosa pancreaticojejunostomy, as a safe and useful anastomotic technique, can reduce pancreatic leakage rate after PD.展开更多
Objective To investigate the relation of methionine synthase (MS) gene variation with congenital heart disease (CHD) phenotype. Methods One hundred and ninety three CHD patients (94 males and 99 females) and their bio...Objective To investigate the relation of methionine synthase (MS) gene variation with congenital heart disease (CHD) phenotype. Methods One hundred and ninety three CHD patients (94 males and 99 females) and their biological parents (nuclear families) in Liaoning Province were selected as the case group, and another 104 normal persons (60 males and 44 females) and their parents without family history of birth defects as the control group. For all subjects the polymorphism of MS gene A2756G locus was examined by PCR-RFLP method. Results In offspring of the control group the frequencies of MS genotype (+/ -) and allele (+) were 10.7% and 5.3%, without existence of homozygote. The MS genotype distribution and allele frequencies of CHD patients and their mothers were not significantly different from the control (P > 0.05). The frequency of allele (+) in case fathers (5.0 %) was apparently lower than that in the control (9.1%, P=0.060), and the odds ratio (OR) was 0.53 (95% CI: 0.25-1.09). There was no difference in parents' genotype combination between the two groups, and in genotype distribution among different types of CHD. Analysis of genetic transmission indicated that mutation allele (+) existed transmission disequilibrium in CHD nuclear families. The percentage of allele (+) transmitted from parents was lower than that allele (-) with OR 0.26 (95% CI: 0.11-0.60). Conclusion MS gene variation in parents is associated with occurrence of CHD in offspring, and mutation allele (+) in parents may be related with the decrease of CHD risk in offspring.展开更多
AIM: To investigate the anti-lipid peroxidation and protection of liver mitochondria against injuries in mice with liver damage by picroside Ⅱ. METHODS: Three animal models of liver damage induced by carbon tetrachlo...AIM: To investigate the anti-lipid peroxidation and protection of liver mitochondria against injuries in mice with liver damage by picroside Ⅱ. METHODS: Three animal models of liver damage induced by carbon tetrachloride (CCl4: 0.1 mL/10 g, ip), D-galactasamine (D-GaIN: 500 mg/kg, ip) and acetaminophen (AP: 0.15 g/kg, ip) were respectively treated with various concentrations of picroside Ⅱ (5, 10, 20 mg/kg, ig). Then we chose the continuously monitoring method (recommended by International Clinical Chemistry League) to analyze serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values, Marland method to detect the activity of manganese-superoxide dismutase (SOD) in liver mitochondria, TBA colorimetry to determine the content of malonicdialdehyde (MDA) in liver tissue, DTNB method to evaluate the activity of glutathioneperoxidase (GSH-Px) and Lowry method to detect protein level in liver tissue. Meanwhile, effects of picroside Ⅱ on the activity of ATPase and swelling extent of mitochondria in hepatocytes damaged by AP were also evaluated. RESULTS: Picroside Ⅱ could significantly prevent liver toxicity in the three models of liver damage. It decreased the high levels of ALT and AST in serum induced by the administration of CCl4, D-GaIN and AP, reduced the cellular damage of liver markedly, and appeared to be even more potent than the positive control drug of biphenyl dimethyl dicarboxylate pilules (DDB). In groups treated with different doses of picroside Ⅱ, compared to the model group, the content of MDA in serum decreased evidently, whereas the content of SOD and GSH-Px increased in a dose dependent manner, and the difference was statistically significant. Further, in the study of AP model, picroside Ⅱ inhibited AP-induced liver toxicity in mice, enhanced the activity of ATPase, improved the swelling extent of mitochondria and helped to maintain a normal balance of energy metabolism. CONCLUSION: Picroside II can evidently relieve hepatocyte injuries induced by CCI4, D-GaIN and AP, help scavenge free radicals, protect normal constructions of mitochondria membrane and enhance the activity of ATPase in mitochondria, thereby modulating the balance of liver energy metabolism, which might be part of the mechanisms of hepatoprotective effects of picroside Ⅱ.展开更多
AIM: Many growth factors, such as epidermal growth factor(EGF), are associated with the carcinogenesis. EGF plays itsrole in the proliferation of hepatoma cells through bindingwith EGF receptor (EGFR) and a series of ...AIM: Many growth factors, such as epidermal growth factor(EGF), are associated with the carcinogenesis. EGF plays itsrole in the proliferation of hepatoma cells through bindingwith EGF receptor (EGFR) and a series of signal transduction.But the postreceptor pathway is still not clear. In the presentexperiment, we studied the effect of tyrosine kinase, proteinkinase C, Na+/H+ exchange, calmodulin and voltage-dependent Ca2+ channel on EGF-induced hepatoma cellproliferation.METHODS: Hepatoma cell line SMMC7721 was cultured inRPMI1640 serum-free medium. In order to study the effectof thyrosine kinase, protein kinase C, Na+/H+ exchange,calmodulin and voltage-dependent Ca2+ channel on humanheptoma cell proliferation induced by epidermal growth factor(EGF), DNA synthesis rate of hepatoma cells was measuredby the method of 3H-TdR incorporation.RESULTS: EGF (10-9 M) stimulated the proliferation of heptomacells significantly (3H-TdR incorporation was 1 880+281 cpm/well, P＜0.05), and this effect was significantly inhibited bytyrosine kinase inhibitor genistein (3H-TdR incorporation was808±209 cpm/well, P＜0.001). Calmedulin inhibitor W-7, proteinkinase C inhibitor H-7 and Na+/H+ exchange inhibitor amilorideindividually had significant inhibiting effect on EGF-inducedproliferation of hepatoma cells (3H-TdR incorporation was978±87.3 cpm/well, 1 241+147 cpm/well, 1 380+189 cpm/well, respectivly, P＜0.001, P＜0.01, P＜0.05), but they allhad no effect on the basal level proliferation of culturedhepatoma cells (3H-TdR incorporation was 1 284+260 cpm/well, 1 179+150 cpm/well, 1 392+152 cpm/well, respectivly,3H-TdR incorporation of the control was 1353+175 cpm/well, P＞0.05). Voltage-dependent Ca2+ channel inhibitorverapamil had no inhibition on EGF-induced proliferation ofhepatoma cells (3H-TdR incorporation was 1 637+133 cpm/well, P＞0.05), it also had no effect on the basal levelproliferation of cultured hepatoma cells (3H-TdR incorporationwas 1196+112 cpm/well,P＞0.05).CONCLUSION: Our data suggest that tyrosine kinase, Ca2+-calmodulin-dependent pathway, protein kinase C and Na+/H+ exchange play a critical role in EGF-induced proliferationof hepatoma cells and that the effect of EGF is independentof voltage-dependent Ca2+ channel.展开更多
This study was designed to obtain an understanding of the subjective well-being (SWB) status among China’s urban elderly, and to find out the major factors that could influence the status in question. Our survey was ...This study was designed to obtain an understanding of the subjective well-being (SWB) status among China’s urban elderly, and to find out the major factors that could influence the status in question. Our survey was conducted of 233 urban elderly individuals, and the data was statistically examined by multiple regression analysis with the results that: 1) The SWB of China’s urban elderly was relatively high as only 4.5% of all respondents considered themselves unhappy or very unhappy; 2) Major factors that had an influence on SWB included economic resource, mobility, age and social support; and 3) Five demographic variables accounted for 18.6% of the variance in SWB, which was slightly higher than that of foreign findings. It is concluded that financial security, active participation in physical and social activities, and social support are necessary for the improvement of the SWB of the elderly.展开更多
To study incidence characteristics and causes of injury, and its medical consequences in school children of China. Methods A total of 2 553 school children aged 7-16 years were recruited from Shantou City in Gunagd...To study incidence characteristics and causes of injury, and its medical consequences in school children of China. Methods A total of 2 553 school children aged 7-16 years were recruited from Shantou City in Gunagdong by cluster sampling method, and were investigated with questionnaires on cases of injuries occurred among them from October 1, 1996 to September 30, 1997. Results Injuries tended to increase with children抯 age, with an overall incidence rate of 37.96%, higher in boys than in girls (P<0.05); and 38.1% of children had more than two episodes of injury during this period. Falls took leading place of injury incidence both in boys and girls and in all age groups. Most injuries occurred when they were playing, sporting, riding and walking at home or in school. Self-inflicted injury ranked the first place of all injuries, followed by hurt caused by others (classmates, sibling or others). Moderate and serious injuries accounted for 8% of the total with a disability rate of 121.4/100 000. Conclusions Currently, injury has become one of the serious public health problems in China. For the improvement of children survival, it is crucial to reduce their injury to strengthen research on child safety and to implement safety-promotion programs.展开更多
A new dihydroflavone glycoside was isolated from the underground parts of Glycyrrhiza uralensis. Its structure was elucidated as 7-hydroxyl-4'-O-β-D-(6'-O-α-hydroxylpropionyl) glucopyranosyl dihydroflavone b...A new dihydroflavone glycoside was isolated from the underground parts of Glycyrrhiza uralensis. Its structure was elucidated as 7-hydroxyl-4'-O-β-D-(6'-O-α-hydroxylpropionyl) glucopyranosyl dihydroflavone by spectral methods.展开更多
The application of Penman's method of cell fractionation to plant protoplasts leads to our finding of keratin intermediate filament(IF)-like system in maize protoplasts,which was identified by using immunogold lab...The application of Penman's method of cell fractionation to plant protoplasts leads to our finding of keratin intermediate filament(IF)-like system in maize protoplasts,which was identified by using immunogold labelling with monoclonal antibody of cytokeratin from animal cells.Many gold particles were found to be bound on filaments,linked by 3 nm filaments.After further digestion and extraction with DNase I and ammonium sulphate.IF-like framework-lamina-nuclear matrix system was shown under electron microscope.That IF system exists in plant protoplasts just like in animal cells,and their main component is keratin-like protein.展开更多
This paper shows that exact calculation for transition probability can make some systems deviate fromFermi golden rule seriously. This paper also shows that the corresponding exact calculation of hopping rate inducedb...This paper shows that exact calculation for transition probability can make some systems deviate fromFermi golden rule seriously. This paper also shows that the corresponding exact calculation of hopping rate inducedby phonons for deuteron in Pd-D system with the many-body electron screening, proposed by Ichimaru, can explainthe experimental fact observed in Pd-D system, and predicts that perfection and low-dimension of Pd lattice are veryimportant for the phonon-induced hopping rate enhancement in Pd-D system.展开更多
AIM: To investigate the characteristics and short-term efficacy of sulfasalazine (SASP) in patients with mildly and moderately active ulcerative colitis (UC).METHODS: Two hundred and twenty-eight patients with mildly ...AIM: To investigate the characteristics and short-term efficacy of sulfasalazine (SASP) in patients with mildly and moderately active ulcerative colitis (UC).METHODS: Two hundred and twenty-eight patients with mildly and moderately active UC were recruited, 106patients in 1993-1995, and 122 patients in 2000-2002,they were assigned as the 1990s group (n = 106) and the 2000s group (n = 122), prospectively. The general characteristics, clinical manifestations, colonoscopic and histological data were compared between the two groups.The short-term efficacy and safety of SASP 3 g per d were evaluated.RESULTS: Between 2000s and 1990s groups, the gender ratio of men to women was 1:1.18 and 1:1.04, 57.4%and 50.9% of the patients were between 30 and 49 years old. The gender ratio and age of UC patients were not significantly different. The total course of 50.0% and 37.1% of UC patients was less than 1 year (P＜0.05), 10.6% and 31.2% of the cases had a duration of more than 5 years (P＜0.05) in 2000s and 1990s groups, respectively. The most common clinical type was first episode in 2000s group and chronic relapse in 1990s group. The patients showed a higher frequency of abdominal pain and tenderness in 1990s group than in 2000s group. Erosions were found in 84.4% and 67.9% of patients in 2000s and 1990s groups (P＜0.05). Rough and granular mucosa (67.9%vs43.4%, P＜0.05)and polyps (47.2% vs 32.8%, P＜0.05)were identified in 1990s group more than in 2000s group.There were no significant differences in clinical, colonoscopic and histological classifications. After SASP (1 g thrice per d) treatment for 6 wk, the clinical, colonoscopic and histological remission rates were 71.8%, 21.8% and 16.4%,respectively. In 79 patients with clinical remission, 58.2%and 67.1% remained grade 1 in colonoscopic and histological findings, respectively. The overall effects in first episode type (complete remission in 10, 18.9%, partial remission in 28, 52.8%, and improvement in 9, 17.0%) were better than in chronic relapse type (complete remission in 3,7.5%; partial remission in 16, 40.0%; and improvement in 15, 37.5%) and chronic persistent type (complete remission in 1, 5.9%; partial remission in 6, 35.3%; and improvement in 6, 35.3%) respectively (P＜0.05). In 110patients treated with SASP, 18 patients (16.4%) had adverse reactions. Except for two cases of urticaria and one case of WBC decrease, none of the patients had to stop the treatment because of severe adverse reactions.CONCLUSION: Patients with mildly and moderately active UC in 2000s group had a shorter disease course, milder clinical manifestations, more first episode type and higher frequency of acute mucosal lesions in colonoscopy than in 1990s group. The patients in 1990s group had higher proportion of chronic relapse type and chronic mucosal change in colonoscopy than in 2000s group. The shortterm efficacy of SASP could be mainly remission of clinical manifestations. But more than half of the patients still had light inflammation in colonoscopy and histology. The overall effects of SASP in first episode type were better than those in other types. SASP was a safe and effective drug to treat mildly and moderately active UC.展开更多
Anti-keratin monoclonal antibody AF5 was introduced into fertilized eggs of Xenopus laevis., and its effects on embryonic development were studied. Survival rate of the antikeratin-injected embryos was much lower (onl...Anti-keratin monoclonal antibody AF5 was introduced into fertilized eggs of Xenopus laevis., and its effects on embryonic development were studied. Survival rate of the antikeratin-injected embryos was much lower (only 35.76% at gastrula) than that of the control (74.85% at gastrula), in which embryos were injected with mouse IgG. Most of survivors in the experimental series showed aberrant external appearance. On the other hand, in cleavage stage, ie 2-7 h after fertilization, immunohistochemi-cal staining of embryos showed that the experimental embryos were mostly keratin negative, while embryos of the control ones were keratin positive. When introducing this antikeratin into one cell of a 2-cell embryo, only the unin-jected half of the embryo continued its development while the other half could not develop at all. These results suggested that intact keratin cytoskeleton in early embryos is indispensable to the embryonic development of Xenopus laevis.展开更多
AIM: To identify the expression of Caspase-l(interleukin1.β converting enzyme) and its role in adenoma of the pancreas and chronic pancreatitis.METHODS: The expression of Caspase-1 was assessed in 42 pancreatic cance...AIM: To identify the expression of Caspase-l(interleukin1.β converting enzyme) and its role in adenoma of the pancreas and chronic pancreatitis.METHODS: The expression of Caspase-1 was assessed in 42 pancreatic cancer tissue samples, 38 chronic pancreatitis specimens, and 9 normal pancreatic tissues by immunohistochemistry and Western blot analysis.RESULTS: Overexpression of Caspase-1 was observed in both disorders, but there were differences in the expression patterns in distinct morphologic compartments. Pancreatic cancer tissues showed a clear cytoplasmatic overexpression of Caspase-1 in tumor cells of 71% of the tumors, whereas normal pancreatic tissues showed only occasional immunoreactivity. In chronic pancreatitis, overexpression of Caspase-1 was found in atrophic acinar cells (89 %),hyperplastic ducts (87 %), and dedifferentiating acinar cells (84 %). Although in atrophic cells a clear nuclear expression was found, hyperplastic ducts and dedifferentiating acinar cells showed dear cytoplasmic expression. Western blot analysis revealed a marked expression of the 45 kDa precursor of Caspase-1 in pancreatic cancer and chronic pancreatitis (80 %and 86 %, respectively). Clear bands at 30 kDa, which suggested the p10-p20 heterodimer of active Caspase-1, were found in 60 % of the cancer tissue and 14 % of the pancreatitis tissue specimens, but not in normal pancreatic tissues.CONCLUSION: Overexpression of Caspase-1 is a frequent event in pancreatic disorders and its differential expression patterns may reflect two functions of the protease. One is its participation in the apoptotic pathway in atrophic acinar cells and tumor-surrounding pancreatitis tissue, the other is its possible role in proliferative processes in pancreatic cancer cells and hyperplastic duct cells and dedifferentiating acinar cells in chronic pancreatitis.展开更多
A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the rea...A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear membrane, nuclear pore complexes, and decondensed chromatin etc. Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei. Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only eggderived lamin LIII.展开更多
Dinoflagellate is one of the primitive eukaryotes, whose nucleus may represent one of the transition stages from prokaryotic nucleoid to typical eukaryotic nucleus. Using selective extraction together with embeddment ...Dinoflagellate is one of the primitive eukaryotes, whose nucleus may represent one of the transition stages from prokaryotic nucleoid to typical eukaryotic nucleus. Using selective extraction together with embeddment - free section and whole mount electron microscopy, a delicate nuclear matrix filament network was shown, for the first time, in dinoflagellate Crypthecodinium cohnii nucleus. Chromosome residues are connected with nuclear matrix filaments to form a complete network spreading over the nucleus. Moreover, we demonstrated that the dinoflagellate chromosome retains a protein scaffold after the depletion of DNA and soluble proteins. This scaffold preserves the characteristic morphology of the chromosome. Two dimensional elec-trophoreses indicated that the nuclear matrix and chromosome scaffold are mainly composed of acidic proteins. Our results demonstrated that a framework similar to the nuclear matrix and chromosome scaffold in mammalian cells appears in this primitive eukaryote,suggesting that these structures may have been originated from the early stages of eukaryote evolution.展开更多
A kind of Web voice browser based on improved synchronous linear predictive coding （ISLPC） and Text-toSpeech （TTS） algorithm and Internet application was proposed. The paper analyzes the features of TTS system wit...A kind of Web voice browser based on improved synchronous linear predictive coding （ISLPC） and Text-toSpeech （TTS） algorithm and Internet application was proposed. The paper analyzes the features of TTS system with ISLPC speech synthesis and discusses the design and implementation of ISLPC TTS-based Web voice browser. The browser integrates Web technology, Chinese information processing, artificial intelligence and the key technology of Chinese ISLPC speech synthesis. It＇s a visual and audible web browser that can improve information precision for network users. The evaluation results show that ISLPC-based TTS model has a better performance than other browsers in voice quality and capability of identifying Chinese characters.展开更多
Since its actuation in 1994, the Clinton Administration's National Missile Defense Plan(NMD)has been deeply affected by U. S. domestic politics. U. S. is now again in its year of general election. This article, th...Since its actuation in 1994, the Clinton Administration's National Missile Defense Plan(NMD)has been deeply affected by U. S. domestic politics. U. S. is now again in its year of general election. This article, therefore,intends to analyzethe effect of recent U.S. domestic political development on Clinton Administration's NMD stand.展开更多
Objective Currently, China is in short of thorough and systemic data concerning the patterns and incidence of injuries and related deaths. Guangdong Province as one of the economically advanced areas in China is fa...Objective Currently, China is in short of thorough and systemic data concerning the patterns and incidence of injuries and related deaths. Guangdong Province as one of the economically advanced areas in China is faced with a relatively serious injury problem, and investigation of this problem in this Province will provide valuable information for other provinces and areas in this Country, as well as scientific basis for policy making for injury prevention and control. Methods Analyses are based on the computerized hospital discharge data collected from 322 hospitals in Guangdong Province between 1997 and 2001. Diagnoses are coded according to the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). Results The total hospitalization rate related with injuries increased year by year from 1997 to 2001. The ratio of case-fatality has a decline trend for all injury inpatients, who were mainly caused by motor vehicle accidents, unintentional falls, puncture and cut by machine and others. The constituent ratio of death among patients caused by motor vehicle accidents accounted for 56.13% among the total deaths, which ranked as the first place. The direct medical cost also had an increased trend. Conclusions Data on injuries requiring hospitalization can be used to design and target more effective injury prevention programs. Injury prevention would decrease human sufferings, disability, and associated economic losses.展开更多
The performances of nonlinear WDM systems with different duty cycle are compared by means of numerical simulation.The numerical results show that the optical pulse with duty cycle of 0.5 is superior to the conventiona...The performances of nonlinear WDM systems with different duty cycle are compared by means of numerical simulation.The numerical results show that the optical pulse with duty cycle of 0.5 is superior to the conventional NRZ modulation scheme.The conclusion is different from that of some references.The reason is that inter symbol interference is not included in some references.In fact,inter symbol interference plays an important role in nonlinear WDM system.Although the larger the duty cycle is ,the stronger the effect of the cross-phase modulation and self-phase modulation on nonlinear WDM is,however,the larger the duty cycle is,the stronger the inter symbol interference is.展开更多
文摘Cell cycle progression is regulated by interactions between cyclins and cyclin-dependent kinases (CDKs). p21(WAF1) is one of the CIP/KIP family which inhibits CDKs activity. Increased expression of p21(WAF1) may play an important role in the growth arrest induced in transformed cells. Although the stability of the p21( WAF1) mRNA could be altered by different signals, cell differentiation and numerous influencing factors. However, recent studies suggest that two known mechanisms of epigenesis, i.e.gene inactivation by methylation in promoter region and changes to an inactive chromatin by histone deacetylation, seem to be the best candidate mechanisms for inactivation of p21( WAF1). To date, almost no coding region p21(WAF1) mutations have been found in tumor cells, despite extensive screening of hundreds of various tumors. Hypermethylation of the p21(WAF1) promoter region may represent an alternative mechanism by which the p21(WAF1/CIP1) gene can be inactivated. The reduction of cellular DNMT protein levels also induces a corresponding rapid increase in the cell cycle regulator p21(WAF1) protein demonstrating a regulatory link between DNMT and p21(WAF1) which is independent of methylation of DNA. Both histone hyperacetylation and hypoacetylation appear to be important in the carcinoma process, and induction of the p21(WAF1) gene by histone hyperacetylation may be a mechanism by which dietary fiber prevents carcinogenesis. Here, we review the influence of histone acetylation and DNA methylation on p21(WAF1) transcription, and affection of pathways or factors associated such as p 53, E2A, Sp1 as well as several histone deacetylation inhibitors.
基金the Science Foundation of Fujian Province,No.99-Z-162
文摘AIM: To study the expression and serum level of HBxAg,Fas and FasL in tissues of HCC patients, and to assess the relationship between HBxAg and Fas/FasL system.METHODS: Tissues from 50 patients with HCC were tested for the expression of HBxAg, Fas and FasL by S-P immunohistochemistry. Serum levels of sFas/sFasL and HBsAg/HBeAg were measured by ELISA assay. HBV X gene was detected by PCR in serum and confirmed by automatic sequencing. Fifty cases of liver cirrhosis and 30 normal controls were involved in serum analysis.RESULTS: The expression of HBxAg, Fas and FasL in carcinoma tissues was 96 %, 84 % and 98 %, respectively.Staining of HBxAg, Fas and FasL was observed predominately in cytoplasms, no significant difference was found in intensity between HBxAg, Fas and FasL (P＞0.05). HBxAg, Fas and FasL might express in the same area of carcinoma tissues and this co-expression could be found in most patients with HCC. The mean levels of sFas in serum from HCC, cirrhosis and normal controls were 762.29±391.56 μg@ L-1 835.36±407.33 μg@L-1 and 238.27±135.29 μg@L-1. The mean levels of sFasL in serum from HCC, cirrhosis and normal controls were 156.36±9.61iμg@ L-1, 173.63±18.74 μg@L-1 and 121.96±7.83 μg@ L-1.Statistical analysis showed that both sFas and sFasL in HCC and cirrhosis patients were significantly higher than those in normal controls (P＜0.01). Serum HBV X gene was found in 32 % of HCC patients and ,46 % of cirrhotic patients.There was no significant relationship between serum level of sFas/sFasL and serum X gene detection (P＞0.05). Eight percent of HCC patients with negative HBsAg and HBeAg in serum might have X gene in serum and HBxAg expression in carcinoma tissues.CONCLUSION: Our data suggest that HBxAg and Fas/FasL system plays an important role in the development of human HCC. Expression of HBxAg can leads to expression of Fas/FasL system which and reverse apoptosis of hepatocellular carcinoma induced by FasL.
文摘AIM: To analyze the risk factors for pancreatic leakage after pancreaticoduodenectomy (PD) and to evaluate whether duct-to-mucosa pancreaticojejunostomy could reduce the risk of pancreatic leakage. METHODS: Sixty-two patients who underwent PD at our hospital between January 2000 and November 2003 were reviewed retrospectively. The primary diseases of the patients included pancreas cancer, ampullary cancer, bile duct cancer, islet cell cancer, duodenal cancer, chronic pancreatitis, pancreatic cystadenoma, and gastric cancer. Standard PD was performed for 25 cases, PD with extended lymphadenectomy for 27 cases, pylorus-preserving PD for 10 cases. A duct-to-mucosa pancreaticojejunostomy was performed for patients with a hard pancreas and a dilated pancreatic duct, and a traditional end-to-end invagination pancreaticojejunostomy for patients with a soft pancreas and a non-dilated duct. Patients were divided into two groups according to the incidence of postoperative pancreaticojejunal anastomotic leakage: 10 cases with leakage and 52 cases without leakage. Seven preoperative and six intraoperative risk factors with the potential to affect the incidence of pancreatic leakage were analyzed with SPSS10.0 software. Logistic regression was then used to determine the effect of multiple factors on pancreatic leakage. RESULTS: Of the 62 patients, 10 (16.13%) were identified as having pancreatic leakage after operation. Other major postoperative complications included delayed gastric emptying (eight patients), abdominal bleeding (four patients), abdominal abscess (three patients) and wound infection (two patients). The overall surgical morbidity was 43.5% (27/62). The hospital mortality in this series was 4.84% (3/62), and the mortality associated with pancreatic fistula was 10% (1/10). Sixteen cases underwent duct-to-mucosa pancreaticojejunostomy and 1 case (1/16, 6.25%) devel-oped postoperative pancreatic leakage, 46 cases underwent invagination pancreaticojejunostomy and 9 cases (9/46, 19.6%) developed postoperative pancreatic leakage. General risk factors including patient age, gender, history of jaundice, preoperative nutrition, pathological diagnosis and the length of postoperative stay were similar in the two groups. There was no statistical difference in the incidence of pancreatic leakage between the patients who received the prophylactic use of octreotide after surgery and the patients who did not undergo somatostatin therapy. Moreover, multivariate logistic regression analysis showed that none of the above factors seemed to be associated with pancreatic fistula. Two intraoperative risk factors, pancreatic duct size and texture of the remnant pancreas, were found to be significantly associated with pancreatic leakage. The incidence of pancreatic leakage was 4.88% in patients with a pancreatic duct size greater than or equal to 3 mm and was 38.1% in those with ducts smaller than 3 mm (P = 0.002). The pancreatic leakage rate was 2.94% in patients with a hard pancreas and was 32.1% in those with a soft pancreas (P = 0.004). Operative time, blood loss and type of resection were similar in the two patient groups. The incidence of pancreatic leakage was 6.25% (1/16) in patients with duct-to-mucosa anastomosis, and was 19.6% (9/46) in those with traditional invagination anastomosis. Although the difference of pancreatic leakage between the two groups was obvious, no statistical signific-ance was found. This may be due to the small number of patients with duct-to-mucosa anastomosis. By further analyzing with multivariate logistic regression, both pancreatic duct size and texture of the remnant pancreas were demonstrated to be independent risk factors (P= 0.007 and 0.017, OR = 11.87 and 15.45). Although anastomotic technique was not a significant factor, pancreatic leakage rate was much less in cases that underwent duct-to-mucosa pancreaticojejunostomy. CONCLUSION: Pancreatic duct size and texture of the remnant pancreas are risk factors influencing pancreatic leakage after PD. Duct-to-mucosa pancreaticojejunostomy, as a safe and useful anastomotic technique, can reduce pancreatic leakage rate after PD.
基金This work was supported by the Major State Basic Research Development Program of People's Republic of China (G1999055904) the Danone's Diet and Nutrition Research and Education Grant (DIC2002-08).
文摘Objective To investigate the relation of methionine synthase (MS) gene variation with congenital heart disease (CHD) phenotype. Methods One hundred and ninety three CHD patients (94 males and 99 females) and their biological parents (nuclear families) in Liaoning Province were selected as the case group, and another 104 normal persons (60 males and 44 females) and their parents without family history of birth defects as the control group. For all subjects the polymorphism of MS gene A2756G locus was examined by PCR-RFLP method. Results In offspring of the control group the frequencies of MS genotype (+/ -) and allele (+) were 10.7% and 5.3%, without existence of homozygote. The MS genotype distribution and allele frequencies of CHD patients and their mothers were not significantly different from the control (P > 0.05). The frequency of allele (+) in case fathers (5.0 %) was apparently lower than that in the control (9.1%, P=0.060), and the odds ratio (OR) was 0.53 (95% CI: 0.25-1.09). There was no difference in parents' genotype combination between the two groups, and in genotype distribution among different types of CHD. Analysis of genetic transmission indicated that mutation allele (+) existed transmission disequilibrium in CHD nuclear families. The percentage of allele (+) transmitted from parents was lower than that allele (-) with OR 0.26 (95% CI: 0.11-0.60). Conclusion MS gene variation in parents is associated with occurrence of CHD in offspring, and mutation allele (+) in parents may be related with the decrease of CHD risk in offspring.
基金Supported by the China Postdoctoral Science Foundation and the National Natural Science Foundation of China, No. 90209046
文摘AIM: To investigate the anti-lipid peroxidation and protection of liver mitochondria against injuries in mice with liver damage by picroside Ⅱ. METHODS: Three animal models of liver damage induced by carbon tetrachloride (CCl4: 0.1 mL/10 g, ip), D-galactasamine (D-GaIN: 500 mg/kg, ip) and acetaminophen (AP: 0.15 g/kg, ip) were respectively treated with various concentrations of picroside Ⅱ (5, 10, 20 mg/kg, ig). Then we chose the continuously monitoring method (recommended by International Clinical Chemistry League) to analyze serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values, Marland method to detect the activity of manganese-superoxide dismutase (SOD) in liver mitochondria, TBA colorimetry to determine the content of malonicdialdehyde (MDA) in liver tissue, DTNB method to evaluate the activity of glutathioneperoxidase (GSH-Px) and Lowry method to detect protein level in liver tissue. Meanwhile, effects of picroside Ⅱ on the activity of ATPase and swelling extent of mitochondria in hepatocytes damaged by AP were also evaluated. RESULTS: Picroside Ⅱ could significantly prevent liver toxicity in the three models of liver damage. It decreased the high levels of ALT and AST in serum induced by the administration of CCl4, D-GaIN and AP, reduced the cellular damage of liver markedly, and appeared to be even more potent than the positive control drug of biphenyl dimethyl dicarboxylate pilules (DDB). In groups treated with different doses of picroside Ⅱ, compared to the model group, the content of MDA in serum decreased evidently, whereas the content of SOD and GSH-Px increased in a dose dependent manner, and the difference was statistically significant. Further, in the study of AP model, picroside Ⅱ inhibited AP-induced liver toxicity in mice, enhanced the activity of ATPase, improved the swelling extent of mitochondria and helped to maintain a normal balance of energy metabolism. CONCLUSION: Picroside II can evidently relieve hepatocyte injuries induced by CCI4, D-GaIN and AP, help scavenge free radicals, protect normal constructions of mitochondria membrane and enhance the activity of ATPase in mitochondria, thereby modulating the balance of liver energy metabolism, which might be part of the mechanisms of hepatoprotective effects of picroside Ⅱ.
文摘AIM: Many growth factors, such as epidermal growth factor(EGF), are associated with the carcinogenesis. EGF plays itsrole in the proliferation of hepatoma cells through bindingwith EGF receptor (EGFR) and a series of signal transduction.But the postreceptor pathway is still not clear. In the presentexperiment, we studied the effect of tyrosine kinase, proteinkinase C, Na+/H+ exchange, calmodulin and voltage-dependent Ca2+ channel on EGF-induced hepatoma cellproliferation.METHODS: Hepatoma cell line SMMC7721 was cultured inRPMI1640 serum-free medium. In order to study the effectof thyrosine kinase, protein kinase C, Na+/H+ exchange,calmodulin and voltage-dependent Ca2+ channel on humanheptoma cell proliferation induced by epidermal growth factor(EGF), DNA synthesis rate of hepatoma cells was measuredby the method of 3H-TdR incorporation.RESULTS: EGF (10-9 M) stimulated the proliferation of heptomacells significantly (3H-TdR incorporation was 1 880+281 cpm/well, P＜0.05), and this effect was significantly inhibited bytyrosine kinase inhibitor genistein (3H-TdR incorporation was808±209 cpm/well, P＜0.001). Calmedulin inhibitor W-7, proteinkinase C inhibitor H-7 and Na+/H+ exchange inhibitor amilorideindividually had significant inhibiting effect on EGF-inducedproliferation of hepatoma cells (3H-TdR incorporation was978±87.3 cpm/well, 1 241+147 cpm/well, 1 380+189 cpm/well, respectivly, P＜0.001, P＜0.01, P＜0.05), but they allhad no effect on the basal level proliferation of culturedhepatoma cells (3H-TdR incorporation was 1 284+260 cpm/well, 1 179+150 cpm/well, 1 392+152 cpm/well, respectivly,3H-TdR incorporation of the control was 1353+175 cpm/well, P＞0.05). Voltage-dependent Ca2+ channel inhibitorverapamil had no inhibition on EGF-induced proliferation ofhepatoma cells (3H-TdR incorporation was 1 637+133 cpm/well, P＞0.05), it also had no effect on the basal levelproliferation of cultured hepatoma cells (3H-TdR incorporationwas 1196+112 cpm/well,P＞0.05).CONCLUSION: Our data suggest that tyrosine kinase, Ca2+-calmodulin-dependent pathway, protein kinase C and Na+/H+ exchange play a critical role in EGF-induced proliferationof hepatoma cells and that the effect of EGF is independentof voltage-dependent Ca2+ channel.
文摘This study was designed to obtain an understanding of the subjective well-being (SWB) status among China’s urban elderly, and to find out the major factors that could influence the status in question. Our survey was conducted of 233 urban elderly individuals, and the data was statistically examined by multiple regression analysis with the results that: 1) The SWB of China’s urban elderly was relatively high as only 4.5% of all respondents considered themselves unhappy or very unhappy; 2) Major factors that had an influence on SWB included economic resource, mobility, age and social support; and 3) Five demographic variables accounted for 18.6% of the variance in SWB, which was slightly higher than that of foreign findings. It is concluded that financial security, active participation in physical and social activities, and social support are necessary for the improvement of the SWB of the elderly.
文摘To study incidence characteristics and causes of injury, and its medical consequences in school children of China. Methods A total of 2 553 school children aged 7-16 years were recruited from Shantou City in Gunagdong by cluster sampling method, and were investigated with questionnaires on cases of injuries occurred among them from October 1, 1996 to September 30, 1997. Results Injuries tended to increase with children抯 age, with an overall incidence rate of 37.96%, higher in boys than in girls (P<0.05); and 38.1% of children had more than two episodes of injury during this period. Falls took leading place of injury incidence both in boys and girls and in all age groups. Most injuries occurred when they were playing, sporting, riding and walking at home or in school. Self-inflicted injury ranked the first place of all injuries, followed by hurt caused by others (classmates, sibling or others). Moderate and serious injuries accounted for 8% of the total with a disability rate of 121.4/100 000. Conclusions Currently, injury has become one of the serious public health problems in China. For the improvement of children survival, it is crucial to reduce their injury to strengthen research on child safety and to implement safety-promotion programs.
文摘A new dihydroflavone glycoside was isolated from the underground parts of Glycyrrhiza uralensis. Its structure was elucidated as 7-hydroxyl-4'-O-β-D-(6'-O-α-hydroxylpropionyl) glucopyranosyl dihydroflavone by spectral methods.
文摘The application of Penman's method of cell fractionation to plant protoplasts leads to our finding of keratin intermediate filament(IF)-like system in maize protoplasts,which was identified by using immunogold labelling with monoclonal antibody of cytokeratin from animal cells.Many gold particles were found to be bound on filaments,linked by 3 nm filaments.After further digestion and extraction with DNase I and ammonium sulphate.IF-like framework-lamina-nuclear matrix system was shown under electron microscope.That IF system exists in plant protoplasts just like in animal cells,and their main component is keratin-like protein.
文摘This paper shows that exact calculation for transition probability can make some systems deviate fromFermi golden rule seriously. This paper also shows that the corresponding exact calculation of hopping rate inducedby phonons for deuteron in Pd-D system with the many-body electron screening, proposed by Ichimaru, can explainthe experimental fact observed in Pd-D system, and predicts that perfection and low-dimension of Pd lattice are veryimportant for the phonon-induced hopping rate enhancement in Pd-D system.
文摘AIM: To investigate the characteristics and short-term efficacy of sulfasalazine (SASP) in patients with mildly and moderately active ulcerative colitis (UC).METHODS: Two hundred and twenty-eight patients with mildly and moderately active UC were recruited, 106patients in 1993-1995, and 122 patients in 2000-2002,they were assigned as the 1990s group (n = 106) and the 2000s group (n = 122), prospectively. The general characteristics, clinical manifestations, colonoscopic and histological data were compared between the two groups.The short-term efficacy and safety of SASP 3 g per d were evaluated.RESULTS: Between 2000s and 1990s groups, the gender ratio of men to women was 1:1.18 and 1:1.04, 57.4%and 50.9% of the patients were between 30 and 49 years old. The gender ratio and age of UC patients were not significantly different. The total course of 50.0% and 37.1% of UC patients was less than 1 year (P＜0.05), 10.6% and 31.2% of the cases had a duration of more than 5 years (P＜0.05) in 2000s and 1990s groups, respectively. The most common clinical type was first episode in 2000s group and chronic relapse in 1990s group. The patients showed a higher frequency of abdominal pain and tenderness in 1990s group than in 2000s group. Erosions were found in 84.4% and 67.9% of patients in 2000s and 1990s groups (P＜0.05). Rough and granular mucosa (67.9%vs43.4%, P＜0.05)and polyps (47.2% vs 32.8%, P＜0.05)were identified in 1990s group more than in 2000s group.There were no significant differences in clinical, colonoscopic and histological classifications. After SASP (1 g thrice per d) treatment for 6 wk, the clinical, colonoscopic and histological remission rates were 71.8%, 21.8% and 16.4%,respectively. In 79 patients with clinical remission, 58.2%and 67.1% remained grade 1 in colonoscopic and histological findings, respectively. The overall effects in first episode type (complete remission in 10, 18.9%, partial remission in 28, 52.8%, and improvement in 9, 17.0%) were better than in chronic relapse type (complete remission in 3,7.5%; partial remission in 16, 40.0%; and improvement in 15, 37.5%) and chronic persistent type (complete remission in 1, 5.9%; partial remission in 6, 35.3%; and improvement in 6, 35.3%) respectively (P＜0.05). In 110patients treated with SASP, 18 patients (16.4%) had adverse reactions. Except for two cases of urticaria and one case of WBC decrease, none of the patients had to stop the treatment because of severe adverse reactions.CONCLUSION: Patients with mildly and moderately active UC in 2000s group had a shorter disease course, milder clinical manifestations, more first episode type and higher frequency of acute mucosal lesions in colonoscopy than in 1990s group. The patients in 1990s group had higher proportion of chronic relapse type and chronic mucosal change in colonoscopy than in 2000s group. The shortterm efficacy of SASP could be mainly remission of clinical manifestations. But more than half of the patients still had light inflammation in colonoscopy and histology. The overall effects of SASP in first episode type were better than those in other types. SASP was a safe and effective drug to treat mildly and moderately active UC.
文摘Anti-keratin monoclonal antibody AF5 was introduced into fertilized eggs of Xenopus laevis., and its effects on embryonic development were studied. Survival rate of the antikeratin-injected embryos was much lower (only 35.76% at gastrula) than that of the control (74.85% at gastrula), in which embryos were injected with mouse IgG. Most of survivors in the experimental series showed aberrant external appearance. On the other hand, in cleavage stage, ie 2-7 h after fertilization, immunohistochemi-cal staining of embryos showed that the experimental embryos were mostly keratin negative, while embryos of the control ones were keratin positive. When introducing this antikeratin into one cell of a 2-cell embryo, only the unin-jected half of the embryo continued its development while the other half could not develop at all. These results suggested that intact keratin cytoskeleton in early embryos is indispensable to the embryonic development of Xenopus laevis.
文摘AIM: To identify the expression of Caspase-l(interleukin1.β converting enzyme) and its role in adenoma of the pancreas and chronic pancreatitis.METHODS: The expression of Caspase-1 was assessed in 42 pancreatic cancer tissue samples, 38 chronic pancreatitis specimens, and 9 normal pancreatic tissues by immunohistochemistry and Western blot analysis.RESULTS: Overexpression of Caspase-1 was observed in both disorders, but there were differences in the expression patterns in distinct morphologic compartments. Pancreatic cancer tissues showed a clear cytoplasmatic overexpression of Caspase-1 in tumor cells of 71% of the tumors, whereas normal pancreatic tissues showed only occasional immunoreactivity. In chronic pancreatitis, overexpression of Caspase-1 was found in atrophic acinar cells (89 %),hyperplastic ducts (87 %), and dedifferentiating acinar cells (84 %). Although in atrophic cells a clear nuclear expression was found, hyperplastic ducts and dedifferentiating acinar cells showed dear cytoplasmic expression. Western blot analysis revealed a marked expression of the 45 kDa precursor of Caspase-1 in pancreatic cancer and chronic pancreatitis (80 %and 86 %, respectively). Clear bands at 30 kDa, which suggested the p10-p20 heterodimer of active Caspase-1, were found in 60 % of the cancer tissue and 14 % of the pancreatitis tissue specimens, but not in normal pancreatic tissues.CONCLUSION: Overexpression of Caspase-1 is a frequent event in pancreatic disorders and its differential expression patterns may reflect two functions of the protease. One is its participation in the apoptotic pathway in atrophic acinar cells and tumor-surrounding pancreatitis tissue, the other is its possible role in proliferative processes in pancreatic cancer cells and hyperplastic duct cells and dedifferentiating acinar cells in chronic pancreatitis.
文摘A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear membrane, nuclear pore complexes, and decondensed chromatin etc. Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei. Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only eggderived lamin LIII.
文摘Dinoflagellate is one of the primitive eukaryotes, whose nucleus may represent one of the transition stages from prokaryotic nucleoid to typical eukaryotic nucleus. Using selective extraction together with embeddment - free section and whole mount electron microscopy, a delicate nuclear matrix filament network was shown, for the first time, in dinoflagellate Crypthecodinium cohnii nucleus. Chromosome residues are connected with nuclear matrix filaments to form a complete network spreading over the nucleus. Moreover, we demonstrated that the dinoflagellate chromosome retains a protein scaffold after the depletion of DNA and soluble proteins. This scaffold preserves the characteristic morphology of the chromosome. Two dimensional elec-trophoreses indicated that the nuclear matrix and chromosome scaffold are mainly composed of acidic proteins. Our results demonstrated that a framework similar to the nuclear matrix and chromosome scaffold in mammalian cells appears in this primitive eukaryote,suggesting that these structures may have been originated from the early stages of eukaryote evolution.
基金Supported by the National High-Technology Re-search and Development Program(2005AA122210) the National Out-standing Youth Foundation (60325104)
文摘A kind of Web voice browser based on improved synchronous linear predictive coding （ISLPC） and Text-toSpeech （TTS） algorithm and Internet application was proposed. The paper analyzes the features of TTS system with ISLPC speech synthesis and discusses the design and implementation of ISLPC TTS-based Web voice browser. The browser integrates Web technology, Chinese information processing, artificial intelligence and the key technology of Chinese ISLPC speech synthesis. It＇s a visual and audible web browser that can improve information precision for network users. The evaluation results show that ISLPC-based TTS model has a better performance than other browsers in voice quality and capability of identifying Chinese characters.
文摘Since its actuation in 1994, the Clinton Administration's National Missile Defense Plan(NMD)has been deeply affected by U. S. domestic politics. U. S. is now again in its year of general election. This article, therefore,intends to analyzethe effect of recent U.S. domestic political development on Clinton Administration's NMD stand.
基金This paper is funded by Guangdong Provincial Bureau of Science and Technology China.
文摘Objective Currently, China is in short of thorough and systemic data concerning the patterns and incidence of injuries and related deaths. Guangdong Province as one of the economically advanced areas in China is faced with a relatively serious injury problem, and investigation of this problem in this Province will provide valuable information for other provinces and areas in this Country, as well as scientific basis for policy making for injury prevention and control. Methods Analyses are based on the computerized hospital discharge data collected from 322 hospitals in Guangdong Province between 1997 and 2001. Diagnoses are coded according to the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). Results The total hospitalization rate related with injuries increased year by year from 1997 to 2001. The ratio of case-fatality has a decline trend for all injury inpatients, who were mainly caused by motor vehicle accidents, unintentional falls, puncture and cut by machine and others. The constituent ratio of death among patients caused by motor vehicle accidents accounted for 56.13% among the total deaths, which ranked as the first place. The direct medical cost also had an increased trend. Conclusions Data on injuries requiring hospitalization can be used to design and target more effective injury prevention programs. Injury prevention would decrease human sufferings, disability, and associated economic losses.
文摘The performances of nonlinear WDM systems with different duty cycle are compared by means of numerical simulation.The numerical results show that the optical pulse with duty cycle of 0.5 is superior to the conventional NRZ modulation scheme.The conclusion is different from that of some references.The reason is that inter symbol interference is not included in some references.In fact,inter symbol interference plays an important role in nonlinear WDM system.Although the larger the duty cycle is ,the stronger the effect of the cross-phase modulation and self-phase modulation on nonlinear WDM is,however,the larger the duty cycle is,the stronger the inter symbol interference is.
