A cytological study on Apluda mutica L. revealed that this species was a facultative apomict with 60.74% of apomictic embryo sac formation. Its sexual reproduction exhibited the characteristics of polygonum_type embry...A cytological study on Apluda mutica L. revealed that this species was a facultative apomict with 60.74% of apomictic embryo sac formation. Its sexual reproduction exhibited the characteristics of polygonum_type embryo sac formation. After the 3 megaspores at the micropylar end had degenerated, leaving only the chalazal megaspore in the nucellus, a nucellar cell adjacent to the megaspore differentiated into an aposporous initial, which later developed into a panicum_type embryo sac. It was an aposporous 4_nucleate embryo sac without chromosome reduction and composed of an egg, a single synergid and a central cell with 2 polar nuclei. The chalazal megaspore degenerated before the onset of the division in the aposporous initial cell.展开更多
In. vitro pollination and its embryological studies were carried out in two japonica cultivars of rice (Oryza sativa L.), 'Chunjiang 05' and '95046'. N-6 basic medium supplemented with different exogen...In. vitro pollination and its embryological studies were carried out in two japonica cultivars of rice (Oryza sativa L.), 'Chunjiang 05' and '95046'. N-6 basic medium supplemented with different exogenous hormones was used for ovary culture after in vitro pollination. The main results were as follows: (1) both cultivars were induced to set kernels after in vitro pollination. The frequency of seedset was 52.1%, including 28.4% normal embryo development, 2.2% abnormal embryo development and 21.5% callus formation. (2) The processes of embryo and endosperm development after in vitro pollination were basically as normal as those in vivo, except there was some retardation in the first division of zygotes and primary endosperm nuclei as well as in their subsequent development. However, both kernels and plantlets could be produced finally. (3) A few abnormal embryos were observed, for instance, proembryos with elongated suspensor and vacuolated proembryos. (4) Two types of calli in the cultured ovaries appeared, namely, the compact callus and the fragile callus, which were able to differentiate into adventitious buds and roots.展开更多
The blood supply to the most of abdominal organs is provided by the branches of CT. The SMA supply caecum, ascends colon, all of the small bowels except the upper part of duodenum. Knowledge of variable anatomy of cel...The blood supply to the most of abdominal organs is provided by the branches of CT. The SMA supply caecum, ascends colon, all of the small bowels except the upper part of duodenum. Knowledge of variable anatomy of celiac axis and SMA may be useful in planning and executing radiological interventions such as celiacography and chemoembolization of hepatic and pancreatic tumors. In this study, the uncommon or low percentage cases of CT and SMA are presented in the light of clinical and embryological information. The celiac axises of a total of 30 adult corpses were examined. Dissections of abdominal region were performed in detail according to Cunningham’s manual. Angiographic images of 100 consecutive adult patients who underwent celiac MDCT angiography were evaluated. During autopsies, an incomplete celiac trunk or bifurcation of celiac trunk associated with the hepatomesenteric and gastrosplenic trunks (0.7%) and a celiacomesenteric trunk associated with high origin superior mesenteric artery and gastrosplenic trunk were detected (0.7%). During MDCT angiography, a case of total absence of celiac trunk associated with a hepatosplenomesenteric trunk (0.7%) and also a case of total absence of celiac trunk alone were observed (0.7%). The persistence or unusual development of ventral splanchnic arteries (VSAs) or ventral longitudinal anastomosis may result in variations or the unusual trunks related to celiac axis and SMA. The anomalous trunks of the CT may be result of either the persistence of some parts of the VSAs or ventral longitudinal anastomose that normally disappear or disappearance of parts that normally persist. The prevalence of unusual trunks of celiac axis and SMA in this study is quite low in literature. These abnormal vessels pose problems for surgeons and radiologists. Such vascular anomalies may cause clinical complications following surgical and radiological procedures such as resection of tumor of the pancreatic head, lymphadenectomy, coeliacography, aortic replacement with reimplantation of the trunk and coembolization of pancreatic and liver tumors.展开更多
Chinese narcissus(Narcissus tazetta var.chinensis Roem)blooms but has no seeds.Embryological studies on the species were conducted to discover the causes of its sterility.Its anther wall is composed of four layers of ...Chinese narcissus(Narcissus tazetta var.chinensis Roem)blooms but has no seeds.Embryological studies on the species were conducted to discover the causes of its sterility.Its anther wall is composed of four layers of cells,and its tapetum is of the secretory type.The cytokinesis of microspore mother cells is of the successive type,and the tetrad is tetrahedral.During meiosis of microspore mother cells,some chromosomes lagged,and several micronuclei were found in tetrads.Only 27.7%of the pollen grains contained full cytoplasm,and 1.3%of them germinated in culture medium.No pollen grain,however,could germinate on the stigma.The ovary is trilocular with axile placenta,and the ovules are bitegmic,tenuinucellate,and anatropous.Its embryo sac is of the polygonum type.Most embryo sacs degenerated,and only about 4.5%of the ovules contained a normal embryo sac with an egg cell,two synergids,three antipodal,and a central cell containing two polar nuclei.One reason for the sterility of Chinese narcissus is the abnormality of microsporogenesis and megasporogenesis,in which only a few functional pollen grains and embryo sacs are produced.The other reason is that the pollen grains cannot germinate on the stigma.展开更多
Basic medical education is the cornerstone of healthcare development,directly impacting the well-being of a nation’s population.The advancement of modern medicine has raised increasing demands on the research capabil...Basic medical education is the cornerstone of healthcare development,directly impacting the well-being of a nation’s population.The advancement of modern medicine has raised increasing demands on the research capabilities of medical students.Therefore,it is crucial to foster their research interests and cultivate their research skills early in their education.As core components of basic medical science and introductory courses to immerse medical students in the intricate microscopic world of the human body,histology and embryology are indispensable in medical education,igniting their curiosity.Incorporating cutting-edge research into education courses can effectively stimulate medical students’research interests.This article primarily focuses on histology and embryology to explore how the latest scientific advancements and emerging technologies can be incorporated into basic medical curricula,offering insights and suggestions for future developments in medical education.展开更多
The development of plant embryology in China can be roughly divided into three stages: (1) the initial stage, (2) the stage of establishing plant embryology as a branch of plant sciences, and (3) the stage when plant...The development of plant embryology in China can be roughly divided into three stages: (1) the initial stage, (2) the stage of establishing plant embryology as a branch of plant sciences, and (3) the stage when plant embryology evolves into plant reproductive biology with its vigorous development. It is in the third stage that research work in this field in China has developed rapidly and many of the significant achievements obtained are described in more details in this review. Researches of experimental embryology are not included in this paper.展开更多
We focus on the diagnostic and therapeutic problems of duodenal adenocarcinoma, reporting a case and reviewing the literature. A 65-year old man with adenocarcinoma in the third duodenal portion was successfully treat...We focus on the diagnostic and therapeutic problems of duodenal adenocarcinoma, reporting a case and reviewing the literature. A 65-year old man with adenocarcinoma in the third duodenal portion was successfully treated with a segmental resection of the third part of the duodenum, avoiding a duodeno-cephalo-pancreatectomy. This tumor is very rare and frequently affects the III and IV duodenal portion. A precocious diagnosis and the exact localization of this neoplasia are crucial factors in order to decide the surgical strategy. Given a non-specificity of symptoms, endoscopy with biopsy is the diagnostic gold standard. Duodeno-cephalo-pancreatectomy (DCP) and segmental resection of the duodenum (SRD) are the two surgical options, with overlapping morbidity (27% vs 18%) and post operative mortality (3% vs 1%). The average incidence of postoperative long-term survival is 100%, 73.3% and 31.6% of cases after 1, 3 and 5 years from surgery, respectively. Long-term survival is made worse by two factors: the presence of metastatic lymph nodes and tumor localization in the proximal duodenum. The two surgical options are radical: DCP should be used only for proximal localizations while SRD should be chosen for distal localizations.展开更多
BACKGROUND:The clinicopathological features of uncinate process pancreatic cancer(UPPC) are poorly described.Furthermore the anatomy of the uncinate process and its division during surgery are central to pancreaticodu...BACKGROUND:The clinicopathological features of uncinate process pancreatic cancer(UPPC) are poorly described.Furthermore the anatomy of the uncinate process and its division during surgery are central to pancreaticoduodenectomy for UPPC.We set out to describe the embryology and anatomy of the uncinate process and the clinicopathological features of UPPC.DATA SOURCES:All published case series of UPPC were reviewed and included in this review.RESULTS:The true incidence of UPPC is difficult to quantify,with the reported incidence ranging from 2.5% to 10.7% of pancreatic cancer.There are 5 published series of UPPC including 117 patients,72 males and 45 females,aged from 45-53 years to 61-84 years.The median survival was 5 or 5.5 months in 3 of the series,12.1 months in another based only on potentially resectable lesions and 17 months in another based only on resected cases.CONCLUSIONS:The number of reported series of UPPC is limited,with vague symptoms as the predominant presenting features of the disease.The prognosis is poor with synchronous venous resection demonstrating a survival advantage.展开更多
The arrangement of various biological structures should generally ensure the safety of crucial structures and increase their working efficiency; however, other principles governing the relative positions of structures...The arrangement of various biological structures should generally ensure the safety of crucial structures and increase their working efficiency; however, other principles governing the relative positions of structures in humans have not been reported. The present study therefore investigated other principles using nerves and their companion vessels in the human body as an example. Nerves and blood vessels usually travel together and in the most direct way towards their targets. Human embryology, histology, and gross anatomy suggest that there are many possible positions for these structures during development. However, for mechanical reasons, tougher or stronger structures should take priority. Nerves are tougher than most other structures, followed by arteries, veins, and lymphatic vessels. Nerves should therefore follow the most direct route, and be followed by the arteries, veins, and lymphatic vessels. This general principle should be applicable to all living things.展开更多
Cleft lip with or without cleft palate(CP) is one of the most common congenital malformations. Ultrasonographers involved in the routine 20-wk ultrasound screening could encounter these malformations. The face and pal...Cleft lip with or without cleft palate(CP) is one of the most common congenital malformations. Ultrasonographers involved in the routine 20-wk ultrasound screening could encounter these malformations. The face and palate develop in a very characteristic way. For ultrasonographers involved in screening these patients it is crucial to have a thorough understanding of the embryology of the face. This could help them to make a more accurate diagnosis and save time during the ultrasound. Subsequently, the current postnatal classification will be discussed to facilitate the communication with the CP teams.展开更多
Cloacal malformations are characterized by the confluence of the lower urinary tract,the female reproductive tract,and the rectum to create a common channel with a single opening on the perineum.The presence of a cloa...Cloacal malformations are characterized by the confluence of the lower urinary tract,the female reproductive tract,and the rectum to create a common channel with a single opening on the perineum.The presence of a cloaca is a normal phase of early human embryological development.Between the 4^th and 7^th weeks of gestation,the cloaca undergoes subdivision to form the hindgut and urogenital sinus.Failure of this process results in the congenital anomaly termed persistent cloaca(PC).The term urorectal septum malformation sequence(URSMS)is also used to describe this anomaly.The classic description of this process which is still cited in many standard textbooks dates from the 19th century.However,this has been increasingly called into question by the findings of studies using modern scientific methodology.Urogenital sinus anomalies are defined by the confluence of the urethra and vagina to form a common channel of varying length with a single perineal opening.In this condition,the anorectal canal opens separately on the perineum.The presence of a urogenital sinus represents a transient phase of the normal development of the lower genital tract in the female fetus.However,the form of urogenital sinus most commonly encountered in the developed world is a feature of disordered sexual differentiation and does not arise simply from the persistence of the anatomical structure which is a feature of normal fetal development.展开更多
The ovule of Doritis pulcherrima Lindl.is anatropous,tenuinucellate and bitegmic.The mature megagametophyte is composed of seven cells with eight nuclei and its formation belongs to Allium type.Its embryo sac matures ...The ovule of Doritis pulcherrima Lindl.is anatropous,tenuinucellate and bitegmic.The mature megagametophyte is composed of seven cells with eight nuclei and its formation belongs to Allium type.Its embryo sac matures about 45 d after pollination.The megasporogenesis in vitro by ovule culture can be induced on all media whether with exogenous hormones or not 3 d after inoculation,but the later megagametogenesis will stop on the medium without hormone or only with auxin or cytokinin.Mature embryo sac can form from megaspore mother cell on the modified VW medium supplemented with 0.5 mg/L BA and 0.1 mg/L NAA.展开更多
AIM To explore the relationship between the rules of Cx gene expression and cellular differentiation in organs of different embryonic stages. METHODS A series of Cx gene serving as molecular probes and the Northern...AIM To explore the relationship between the rules of Cx gene expression and cellular differentiation in organs of different embryonic stages. METHODS A series of Cx gene serving as molecular probes and the Northern blot hybrydization were employed to study the Cx gene expression. RESULTS Cx31, Cx31 1, Cx46 did not express while other Cx genes expressed in the embryonic liver and stomach. The Cx gene expression in the liver and stomach showed different state at different embryonic stages. The Cx gene expression had organic diversity. The expression of Cx26 gene was overlapping in the above organs. Cx43 did not express in the human liver after birth, but it expressed in the embryonic stage. CONCLUSION The expression state of Cx genes is concordant with cellular differentiation. It might be a key candidate gene to regulate some differentiational events associated with cellular differentiation, proliferation, and morphogenesis in the early embryo.展开更多
BACKGROUND Complete mesocolic excision(CME)with central vascular ligation(CVL)was proposed by Hohenberger in 2009.The CME principle has gradually become the technical standard for colon cancer surgery.How to achieve C...BACKGROUND Complete mesocolic excision(CME)with central vascular ligation(CVL)was proposed by Hohenberger in 2009.The CME principle has gradually become the technical standard for colon cancer surgery.How to achieve CME with CVL in laparoscopic right hemicolectomy(LRH)is controversial,and a unified standard approach is not yet available.In recent years,the authors’team has integrated the theory of membrane anatomy,tried to combine the cephalic approach with the classic medial approach(MA)for technical optimization,and proposed a cranialmedial mixed dominant approach(CMA).AIM To explore the feasibility of operational approaches for LRH with CME.METHODS In this retrospective cohort study,the clinical data of 57 patients with right-sided colon cancer(TNM stage I,II,or III)who underwent LRH with CME from January 2016 to June 2020 were collected and summarized.There were 31 patients in the traditional MA group and 26 in the CMA group.RESULTS There were no significant differences in baseline data between the two groups.The operation was shorter and the number of lymph nodes dissected was higher in the CMA group than in the MA group,but there was no significant difference in the number of positive lymph nodes,intraoperative blood loss,postoperative exhaust time,feeding time,postoperative hospital stay or postoperative complication incidence.CONCLUSION Our study shows that the CMA is a safe and feasible procedure for LRH with CME and has a unique advantage.展开更多
Klippel-Feil syndrome(KFS) is defined by congenital cervical vertebral spine fusion and is seen with a wide spectrum of dental manifestations and craniofacial profiles. Previous studies on lateral cephalograms have do...Klippel-Feil syndrome(KFS) is defined by congenital cervical vertebral spine fusion and is seen with a wide spectrum of dental manifestations and craniofacial profiles. Previous studies on lateral cephalograms have documented an association between fusion of the cervicalvertebrae and deviations in the craniofacial profile in non-syndromic patients with severe malocclusion. To our knowledge, no previous studies have described the craniofacial profile including the cranial base of KFS patients on lateral cephalograms. Therefore KFS and its craniofacial and dental manifestations were described according to existing literature and additionally the craniofacial profile and cranial base was analysed on lateral cephalograms of two patients with KFS. According to the literature the dental manifestations of KFS-patients included oligodontia, overjet, cross bite, open bite and deep bite. The craniofacial profile was clinically described as reduced lower facial height, midfacial hypoplasia, and mandibular prognathia. The analyses of the two lateral cephalograms showed increased mandibular inclination, increased vertical jaw-relationship, increased jaw angle and maxillary retrognathia. The cranial base was normal in both cases. The sagittal jaw relationship and mandibular prognathia varied between the two cases. The literature review and the analyses of the two lateral cephalograms have shown that deviations in the occipital and cervical spine field as KFS were associated with deviations in the teeth and craniofacial profile.展开更多
Iris sangumea Dorm ex Horn. is a perennial cold-tolerant herbs of the Iris genus of Iridaceae, which has a well-formed, bright color and adaptability. Through understanding the fl ower bud differentiation, Sporogenesi...Iris sangumea Dorm ex Horn. is a perennial cold-tolerant herbs of the Iris genus of Iridaceae, which has a well-formed, bright color and adaptability. Through understanding the fl ower bud differentiation, Sporogenesis, gametogenesis, fertilization and embryogenesis of I. sangumea, we developed fl owering regulation and control breeding. I. sangumea fl ower bud differentiation was observed in April for 21 days; in this stage, the early differentiation process was slow, temperature was more than 5 °C, if the temperature is shorter than this, most fl ower bud will have no differentiation, and turn to vegetative growth; later differentiation is faster and required temperature is from 5 to 8 °C and gradually rose to 10-12 °C. The temperature in April plays the defi nitely role in the number of bud differentiation. Three stamina contain tetrasporangiate anthers and a glandular tapetum. The anther wall is composed of four cell layers inclduding the epidermis, the endothecium, one middle layer and the secretory tapetum. The type of anther wall development the dicotyledonous type. After pollen maturation, the anther wall forms a double-layer containing only epidermis and endothecium. Simultaneous cytokinesis is of the continuous type during meiosis of microspore mother cell results in a zygomorphous or tetragonal tetrad. Mature pollen grains are two-celled. I. sangumea ’s stylar canal is hollow, open type style, and the gynoecium has three carpels. The ovaries have axial placentas. The ovule is anatropous, bitegmic and crassinucellate. The primary sporogenous cell differentiates directly as the megaspore. The megaspore tetrads are linear, T-shaped or juxtaposed. Generally, the fi rst of the tetrad megaspores at the chalaza becomes functional while the other three degenerate. A mature embryo sac with seven cells and eight nuclei embryo sac is of the polygonum type. For dichogamy, the male gametophyte matures about 2 days earlier than the female gametophyte. The pollen tube entered into the embryo sac for 22–24 h after pollination. The dormancy stage of fertilized ovules is 5-6 days, and the fusion of sperm and egg nucleus is of the premitotic type. The primary endosperm cell has shorter dormancy of 4-6 days, and endosperm formation is of the nuclear type.展开更多
Early human embryonic development remains mysterious due to drastic species divergences between humans and othermammalian models and limited accessibility to human embryo samples. Recent studies from my laboratory and...Early human embryonic development remains mysterious due to drastic species divergences between humans and othermammalian models and limited accessibility to human embryo samples. Recent studies from my laboratory and others haveshown that under suitable culture conditions human pluripotent stem cells ( hPSCs) can undergo intricate morphogenetic eventsand self-organize to form patterned human embryo-like structures in vitro. These synthetic human embryonic tissueshold great promises for advancing human embryology and reproductive medicine. In this talk,I will describe a hPSC-based,synthetic 3D model of human post-implantation development that recapitulates key developmental landmarks successively,including pro-amniotic cavity formation,amniotic ectoderm-epiblast patterning,primordial germ cell specification,and developmentof the primitive streak with controlled anteroposterior polarity ( Fig.1) . We further show that the amniotic ectoderm,as the first lineage that segregates from the epiblast upon implantation of the human embryo,functions as a signaling centerto trigger primitive streak development in the epiblast. Together,our research has developed a powerful synthetic embryologicalmodel and provided new understandings of previously inaccessible but critical embryogenic events in human development.展开更多
Morphological changes during the embryonic development of limbs of the green turtle,Chelonia mydas,were studied during the entire period of incubation,using transmission and scanning electron microscopy(TEM and SEM). ...Morphological changes during the embryonic development of limbs of the green turtle,Chelonia mydas,were studied during the entire period of incubation,using transmission and scanning electron microscopy(TEM and SEM). Limb buds were first observed at Stage 2. At that stage,the tip was covered with an apical ectodermal ridge(AER) which began to regress at Stage 6. Associated with AER was the presence of the mesenchymal cells which,consequently,differentiated into muscles,cartilage and bones. The gross features of the skeletal development appeared as a condensation of the cartilaginous structures in the proximal distal region of the limbs. The primordial digits were gradually enclosed by hard keratinized webbed skin. The increase in rate of ossification and skin pigmentation was correlated with the growth of the limbs. The development of the limbs was closely related to the transitional appearance of mucus secretion from the epidermis.展开更多
The review presents a topological description and interpretation (analysis) of some events in metazoan development and evolution through the use of well-known mathematical concepts and theorems (using topological appr...The review presents a topological description and interpretation (analysis) of some events in metazoan development and evolution through the use of well-known mathematical concepts and theorems (using topological approach). It is the topological language that can provide strict and adequate description of various phenomena in developmental and evolutionary transformations. Topological singularities inevitably arising and transforming during early development destroy the preexisting pattern of symmetry. The symmetry breaking of preexisting spatial pattern plays a critical role in biological morphogenesis in development and evolution. Some events of early development are interpreted in terms of symmetry breakdown and related to well-known mathematical theorems. A topological inevitability of some developmental events through the use of classical topological concepts is discussed. The topological approach makes it possible to consider the succession of spherical surgeries, which change the topological genus of an animal body surface. We model the biological shape as a set of smooth, closed, oriented surfaces—membrane or epithelial layers. Membrane and epithelial surfaces are boundary layers, interfaces between a living structure and its environment, ensuring metabolism. Toroid forms as well as fractal structures in metazoans can be considered as functionally optimized biological design and attractors in biological morphogenesis. The epithelial surface is an interface between the internal medium of an organism and the outside environmental medium;topological and fractal transformations during metazoan evolution and development increase this interface, ensuring better adaptation of organism to the environment. Fractal structures as well as toroid forms can be considered as a functionally optimized design in Metazoa. Topological methodology reveals a certain set of topological rules constraining and directing biological morphogenesis during evolution and development.展开更多
文摘A cytological study on Apluda mutica L. revealed that this species was a facultative apomict with 60.74% of apomictic embryo sac formation. Its sexual reproduction exhibited the characteristics of polygonum_type embryo sac formation. After the 3 megaspores at the micropylar end had degenerated, leaving only the chalazal megaspore in the nucellus, a nucellar cell adjacent to the megaspore differentiated into an aposporous initial, which later developed into a panicum_type embryo sac. It was an aposporous 4_nucleate embryo sac without chromosome reduction and composed of an egg, a single synergid and a central cell with 2 polar nuclei. The chalazal megaspore degenerated before the onset of the division in the aposporous initial cell.
文摘In. vitro pollination and its embryological studies were carried out in two japonica cultivars of rice (Oryza sativa L.), 'Chunjiang 05' and '95046'. N-6 basic medium supplemented with different exogenous hormones was used for ovary culture after in vitro pollination. The main results were as follows: (1) both cultivars were induced to set kernels after in vitro pollination. The frequency of seedset was 52.1%, including 28.4% normal embryo development, 2.2% abnormal embryo development and 21.5% callus formation. (2) The processes of embryo and endosperm development after in vitro pollination were basically as normal as those in vivo, except there was some retardation in the first division of zygotes and primary endosperm nuclei as well as in their subsequent development. However, both kernels and plantlets could be produced finally. (3) A few abnormal embryos were observed, for instance, proembryos with elongated suspensor and vacuolated proembryos. (4) Two types of calli in the cultured ovaries appeared, namely, the compact callus and the fragile callus, which were able to differentiate into adventitious buds and roots.
文摘The blood supply to the most of abdominal organs is provided by the branches of CT. The SMA supply caecum, ascends colon, all of the small bowels except the upper part of duodenum. Knowledge of variable anatomy of celiac axis and SMA may be useful in planning and executing radiological interventions such as celiacography and chemoembolization of hepatic and pancreatic tumors. In this study, the uncommon or low percentage cases of CT and SMA are presented in the light of clinical and embryological information. The celiac axises of a total of 30 adult corpses were examined. Dissections of abdominal region were performed in detail according to Cunningham’s manual. Angiographic images of 100 consecutive adult patients who underwent celiac MDCT angiography were evaluated. During autopsies, an incomplete celiac trunk or bifurcation of celiac trunk associated with the hepatomesenteric and gastrosplenic trunks (0.7%) and a celiacomesenteric trunk associated with high origin superior mesenteric artery and gastrosplenic trunk were detected (0.7%). During MDCT angiography, a case of total absence of celiac trunk associated with a hepatosplenomesenteric trunk (0.7%) and also a case of total absence of celiac trunk alone were observed (0.7%). The persistence or unusual development of ventral splanchnic arteries (VSAs) or ventral longitudinal anastomosis may result in variations or the unusual trunks related to celiac axis and SMA. The anomalous trunks of the CT may be result of either the persistence of some parts of the VSAs or ventral longitudinal anastomose that normally disappear or disappearance of parts that normally persist. The prevalence of unusual trunks of celiac axis and SMA in this study is quite low in literature. These abnormal vessels pose problems for surgeons and radiologists. Such vascular anomalies may cause clinical complications following surgical and radiological procedures such as resection of tumor of the pancreatic head, lymphadenectomy, coeliacography, aortic replacement with reimplantation of the trunk and coembolization of pancreatic and liver tumors.
基金supported by the Fujian Natural Sciences Foundation (No.F0210009).
文摘Chinese narcissus(Narcissus tazetta var.chinensis Roem)blooms but has no seeds.Embryological studies on the species were conducted to discover the causes of its sterility.Its anther wall is composed of four layers of cells,and its tapetum is of the secretory type.The cytokinesis of microspore mother cells is of the successive type,and the tetrad is tetrahedral.During meiosis of microspore mother cells,some chromosomes lagged,and several micronuclei were found in tetrads.Only 27.7%of the pollen grains contained full cytoplasm,and 1.3%of them germinated in culture medium.No pollen grain,however,could germinate on the stigma.The ovary is trilocular with axile placenta,and the ovules are bitegmic,tenuinucellate,and anatropous.Its embryo sac is of the polygonum type.Most embryo sacs degenerated,and only about 4.5%of the ovules contained a normal embryo sac with an egg cell,two synergids,three antipodal,and a central cell containing two polar nuclei.One reason for the sterility of Chinese narcissus is the abnormality of microsporogenesis and megasporogenesis,in which only a few functional pollen grains and embryo sacs are produced.The other reason is that the pollen grains cannot germinate on the stigma.
基金supported by Shanghai Rising-Star Program(22QA1411500)Naval Medical University(2023MS0001).
文摘Basic medical education is the cornerstone of healthcare development,directly impacting the well-being of a nation’s population.The advancement of modern medicine has raised increasing demands on the research capabilities of medical students.Therefore,it is crucial to foster their research interests and cultivate their research skills early in their education.As core components of basic medical science and introductory courses to immerse medical students in the intricate microscopic world of the human body,histology and embryology are indispensable in medical education,igniting their curiosity.Incorporating cutting-edge research into education courses can effectively stimulate medical students’research interests.This article primarily focuses on histology and embryology to explore how the latest scientific advancements and emerging technologies can be incorporated into basic medical curricula,offering insights and suggestions for future developments in medical education.
文摘The development of plant embryology in China can be roughly divided into three stages: (1) the initial stage, (2) the stage of establishing plant embryology as a branch of plant sciences, and (3) the stage when plant embryology evolves into plant reproductive biology with its vigorous development. It is in the third stage that research work in this field in China has developed rapidly and many of the significant achievements obtained are described in more details in this review. Researches of experimental embryology are not included in this paper.
文摘We focus on the diagnostic and therapeutic problems of duodenal adenocarcinoma, reporting a case and reviewing the literature. A 65-year old man with adenocarcinoma in the third duodenal portion was successfully treated with a segmental resection of the third part of the duodenum, avoiding a duodeno-cephalo-pancreatectomy. This tumor is very rare and frequently affects the III and IV duodenal portion. A precocious diagnosis and the exact localization of this neoplasia are crucial factors in order to decide the surgical strategy. Given a non-specificity of symptoms, endoscopy with biopsy is the diagnostic gold standard. Duodeno-cephalo-pancreatectomy (DCP) and segmental resection of the duodenum (SRD) are the two surgical options, with overlapping morbidity (27% vs 18%) and post operative mortality (3% vs 1%). The average incidence of postoperative long-term survival is 100%, 73.3% and 31.6% of cases after 1, 3 and 5 years from surgery, respectively. Long-term survival is made worse by two factors: the presence of metastatic lymph nodes and tumor localization in the proximal duodenum. The two surgical options are radical: DCP should be used only for proximal localizations while SRD should be chosen for distal localizations.
文摘BACKGROUND:The clinicopathological features of uncinate process pancreatic cancer(UPPC) are poorly described.Furthermore the anatomy of the uncinate process and its division during surgery are central to pancreaticoduodenectomy for UPPC.We set out to describe the embryology and anatomy of the uncinate process and the clinicopathological features of UPPC.DATA SOURCES:All published case series of UPPC were reviewed and included in this review.RESULTS:The true incidence of UPPC is difficult to quantify,with the reported incidence ranging from 2.5% to 10.7% of pancreatic cancer.There are 5 published series of UPPC including 117 patients,72 males and 45 females,aged from 45-53 years to 61-84 years.The median survival was 5 or 5.5 months in 3 of the series,12.1 months in another based only on potentially resectable lesions and 17 months in another based only on resected cases.CONCLUSIONS:The number of reported series of UPPC is limited,with vague symptoms as the predominant presenting features of the disease.The prognosis is poor with synchronous venous resection demonstrating a survival advantage.
文摘The arrangement of various biological structures should generally ensure the safety of crucial structures and increase their working efficiency; however, other principles governing the relative positions of structures in humans have not been reported. The present study therefore investigated other principles using nerves and their companion vessels in the human body as an example. Nerves and blood vessels usually travel together and in the most direct way towards their targets. Human embryology, histology, and gross anatomy suggest that there are many possible positions for these structures during development. However, for mechanical reasons, tougher or stronger structures should take priority. Nerves are tougher than most other structures, followed by arteries, veins, and lymphatic vessels. Nerves should therefore follow the most direct route, and be followed by the arteries, veins, and lymphatic vessels. This general principle should be applicable to all living things.
文摘Cleft lip with or without cleft palate(CP) is one of the most common congenital malformations. Ultrasonographers involved in the routine 20-wk ultrasound screening could encounter these malformations. The face and palate develop in a very characteristic way. For ultrasonographers involved in screening these patients it is crucial to have a thorough understanding of the embryology of the face. This could help them to make a more accurate diagnosis and save time during the ultrasound. Subsequently, the current postnatal classification will be discussed to facilitate the communication with the CP teams.
文摘Cloacal malformations are characterized by the confluence of the lower urinary tract,the female reproductive tract,and the rectum to create a common channel with a single opening on the perineum.The presence of a cloaca is a normal phase of early human embryological development.Between the 4^th and 7^th weeks of gestation,the cloaca undergoes subdivision to form the hindgut and urogenital sinus.Failure of this process results in the congenital anomaly termed persistent cloaca(PC).The term urorectal septum malformation sequence(URSMS)is also used to describe this anomaly.The classic description of this process which is still cited in many standard textbooks dates from the 19th century.However,this has been increasingly called into question by the findings of studies using modern scientific methodology.Urogenital sinus anomalies are defined by the confluence of the urethra and vagina to form a common channel of varying length with a single perineal opening.In this condition,the anorectal canal opens separately on the perineum.The presence of a urogenital sinus represents a transient phase of the normal development of the lower genital tract in the female fetus.However,the form of urogenital sinus most commonly encountered in the developed world is a feature of disordered sexual differentiation and does not arise simply from the persistence of the anatomical structure which is a feature of normal fetal development.
文摘The ovule of Doritis pulcherrima Lindl.is anatropous,tenuinucellate and bitegmic.The mature megagametophyte is composed of seven cells with eight nuclei and its formation belongs to Allium type.Its embryo sac matures about 45 d after pollination.The megasporogenesis in vitro by ovule culture can be induced on all media whether with exogenous hormones or not 3 d after inoculation,but the later megagametogenesis will stop on the medium without hormone or only with auxin or cytokinin.Mature embryo sac can form from megaspore mother cell on the modified VW medium supplemented with 0.5 mg/L BA and 0.1 mg/L NAA.
文摘AIM To explore the relationship between the rules of Cx gene expression and cellular differentiation in organs of different embryonic stages. METHODS A series of Cx gene serving as molecular probes and the Northern blot hybrydization were employed to study the Cx gene expression. RESULTS Cx31, Cx31 1, Cx46 did not express while other Cx genes expressed in the embryonic liver and stomach. The Cx gene expression in the liver and stomach showed different state at different embryonic stages. The Cx gene expression had organic diversity. The expression of Cx26 gene was overlapping in the above organs. Cx43 did not express in the human liver after birth, but it expressed in the embryonic stage. CONCLUSION The expression state of Cx genes is concordant with cellular differentiation. It might be a key candidate gene to regulate some differentiational events associated with cellular differentiation, proliferation, and morphogenesis in the early embryo.
文摘BACKGROUND Complete mesocolic excision(CME)with central vascular ligation(CVL)was proposed by Hohenberger in 2009.The CME principle has gradually become the technical standard for colon cancer surgery.How to achieve CME with CVL in laparoscopic right hemicolectomy(LRH)is controversial,and a unified standard approach is not yet available.In recent years,the authors’team has integrated the theory of membrane anatomy,tried to combine the cephalic approach with the classic medial approach(MA)for technical optimization,and proposed a cranialmedial mixed dominant approach(CMA).AIM To explore the feasibility of operational approaches for LRH with CME.METHODS In this retrospective cohort study,the clinical data of 57 patients with right-sided colon cancer(TNM stage I,II,or III)who underwent LRH with CME from January 2016 to June 2020 were collected and summarized.There were 31 patients in the traditional MA group and 26 in the CMA group.RESULTS There were no significant differences in baseline data between the two groups.The operation was shorter and the number of lymph nodes dissected was higher in the CMA group than in the MA group,but there was no significant difference in the number of positive lymph nodes,intraoperative blood loss,postoperative exhaust time,feeding time,postoperative hospital stay or postoperative complication incidence.CONCLUSION Our study shows that the CMA is a safe and feasible procedure for LRH with CME and has a unique advantage.
文摘Klippel-Feil syndrome(KFS) is defined by congenital cervical vertebral spine fusion and is seen with a wide spectrum of dental manifestations and craniofacial profiles. Previous studies on lateral cephalograms have documented an association between fusion of the cervicalvertebrae and deviations in the craniofacial profile in non-syndromic patients with severe malocclusion. To our knowledge, no previous studies have described the craniofacial profile including the cranial base of KFS patients on lateral cephalograms. Therefore KFS and its craniofacial and dental manifestations were described according to existing literature and additionally the craniofacial profile and cranial base was analysed on lateral cephalograms of two patients with KFS. According to the literature the dental manifestations of KFS-patients included oligodontia, overjet, cross bite, open bite and deep bite. The craniofacial profile was clinically described as reduced lower facial height, midfacial hypoplasia, and mandibular prognathia. The analyses of the two lateral cephalograms showed increased mandibular inclination, increased vertical jaw-relationship, increased jaw angle and maxillary retrognathia. The cranial base was normal in both cases. The sagittal jaw relationship and mandibular prognathia varied between the two cases. The literature review and the analyses of the two lateral cephalograms have shown that deviations in the occipital and cervical spine field as KFS were associated with deviations in the teeth and craniofacial profile.
基金supported by the National Natural Science Foundation of China(No.31670344)the Fundamental Research Funds for the Central Universities(2572019DF08)
文摘Iris sangumea Dorm ex Horn. is a perennial cold-tolerant herbs of the Iris genus of Iridaceae, which has a well-formed, bright color and adaptability. Through understanding the fl ower bud differentiation, Sporogenesis, gametogenesis, fertilization and embryogenesis of I. sangumea, we developed fl owering regulation and control breeding. I. sangumea fl ower bud differentiation was observed in April for 21 days; in this stage, the early differentiation process was slow, temperature was more than 5 °C, if the temperature is shorter than this, most fl ower bud will have no differentiation, and turn to vegetative growth; later differentiation is faster and required temperature is from 5 to 8 °C and gradually rose to 10-12 °C. The temperature in April plays the defi nitely role in the number of bud differentiation. Three stamina contain tetrasporangiate anthers and a glandular tapetum. The anther wall is composed of four cell layers inclduding the epidermis, the endothecium, one middle layer and the secretory tapetum. The type of anther wall development the dicotyledonous type. After pollen maturation, the anther wall forms a double-layer containing only epidermis and endothecium. Simultaneous cytokinesis is of the continuous type during meiosis of microspore mother cell results in a zygomorphous or tetragonal tetrad. Mature pollen grains are two-celled. I. sangumea ’s stylar canal is hollow, open type style, and the gynoecium has three carpels. The ovaries have axial placentas. The ovule is anatropous, bitegmic and crassinucellate. The primary sporogenous cell differentiates directly as the megaspore. The megaspore tetrads are linear, T-shaped or juxtaposed. Generally, the fi rst of the tetrad megaspores at the chalaza becomes functional while the other three degenerate. A mature embryo sac with seven cells and eight nuclei embryo sac is of the polygonum type. For dichogamy, the male gametophyte matures about 2 days earlier than the female gametophyte. The pollen tube entered into the embryo sac for 22–24 h after pollination. The dormancy stage of fertilized ovules is 5-6 days, and the fusion of sperm and egg nucleus is of the premitotic type. The primary endosperm cell has shorter dormancy of 4-6 days, and endosperm formation is of the nuclear type.
基金supported by the National Science Foundation ( CMMI 1129611 and CBET 1149401)the National Institutes of Health ( R21 HL114011 and R21 EB017078)+3 种基金the American Heart Association ( 12SDG12180025)the Department of Mechanical Engineering at the University of Michigan,Ann ArborThe Lurie Nanofabrication Facility at the University of Michigan,a member of the National Nanotechnology Infrastructure Network ( NNIN)funded by the National Science Foundation,is acknowledged for support in microfabrication
文摘Early human embryonic development remains mysterious due to drastic species divergences between humans and othermammalian models and limited accessibility to human embryo samples. Recent studies from my laboratory and others haveshown that under suitable culture conditions human pluripotent stem cells ( hPSCs) can undergo intricate morphogenetic eventsand self-organize to form patterned human embryo-like structures in vitro. These synthetic human embryonic tissueshold great promises for advancing human embryology and reproductive medicine. In this talk,I will describe a hPSC-based,synthetic 3D model of human post-implantation development that recapitulates key developmental landmarks successively,including pro-amniotic cavity formation,amniotic ectoderm-epiblast patterning,primordial germ cell specification,and developmentof the primitive streak with controlled anteroposterior polarity ( Fig.1) . We further show that the amniotic ectoderm,as the first lineage that segregates from the epiblast upon implantation of the human embryo,functions as a signaling centerto trigger primitive streak development in the epiblast. Together,our research has developed a powerful synthetic embryologicalmodel and provided new understandings of previously inaccessible but critical embryogenic events in human development.
文摘Morphological changes during the embryonic development of limbs of the green turtle,Chelonia mydas,were studied during the entire period of incubation,using transmission and scanning electron microscopy(TEM and SEM). Limb buds were first observed at Stage 2. At that stage,the tip was covered with an apical ectodermal ridge(AER) which began to regress at Stage 6. Associated with AER was the presence of the mesenchymal cells which,consequently,differentiated into muscles,cartilage and bones. The gross features of the skeletal development appeared as a condensation of the cartilaginous structures in the proximal distal region of the limbs. The primordial digits were gradually enclosed by hard keratinized webbed skin. The increase in rate of ossification and skin pigmentation was correlated with the growth of the limbs. The development of the limbs was closely related to the transitional appearance of mucus secretion from the epidermis.
文摘The review presents a topological description and interpretation (analysis) of some events in metazoan development and evolution through the use of well-known mathematical concepts and theorems (using topological approach). It is the topological language that can provide strict and adequate description of various phenomena in developmental and evolutionary transformations. Topological singularities inevitably arising and transforming during early development destroy the preexisting pattern of symmetry. The symmetry breaking of preexisting spatial pattern plays a critical role in biological morphogenesis in development and evolution. Some events of early development are interpreted in terms of symmetry breakdown and related to well-known mathematical theorems. A topological inevitability of some developmental events through the use of classical topological concepts is discussed. The topological approach makes it possible to consider the succession of spherical surgeries, which change the topological genus of an animal body surface. We model the biological shape as a set of smooth, closed, oriented surfaces—membrane or epithelial layers. Membrane and epithelial surfaces are boundary layers, interfaces between a living structure and its environment, ensuring metabolism. Toroid forms as well as fractal structures in metazoans can be considered as functionally optimized biological design and attractors in biological morphogenesis. The epithelial surface is an interface between the internal medium of an organism and the outside environmental medium;topological and fractal transformations during metazoan evolution and development increase this interface, ensuring better adaptation of organism to the environment. Fractal structures as well as toroid forms can be considered as a functionally optimized design in Metazoa. Topological methodology reveals a certain set of topological rules constraining and directing biological morphogenesis during evolution and development.
