Radiation therapy(RT)is a treatment option for head and neck cancer(HNC),but 2%of RT patients may experience damage to the jawbone,resulting in osteoradionecrosis(ORN).The ORN can manifest years after RT exposure.Chan...Radiation therapy(RT)is a treatment option for head and neck cancer(HNC),but 2%of RT patients may experience damage to the jawbone,resulting in osteoradionecrosis(ORN).The ORN can manifest years after RT exposure.Changes in the local microchemical bone quality prior to the clinical manifestation of ORN could play a key role in ORN pathogenesis.Chemical bone quality can be analyzed using Fourier transform infrared spectroscopy(FTIR),that is applied to examine the effects of cancer,chemotherapy,and RT on the quality of human man-dibular bone.Cortical mandibular bone samples were harvested from dental implant beds of 23 individuals,i.e.,patients with surgically and radiotherapeutically treated HNC(RT-HNC,n=7),surgically and radiochemotherapeutically treated HNC(CH-RT-HNC,n=3),only surgically treated HNC(SRG-HNC,n=4),and healthy controls(n=9).Infrared spectra were acquired from two representative regions of interest in cortical mandibular bone.Spectral parameters,i.e.,mineral-to-matrix ratio(MM),carbonate-to-matrix ratio(CM),carbonate-to-phosphate ratio(CP),collagen maturity(cross-linking),crystallinity,acid phosphate substitu-tion(APS),and advanced glycation end products(AGEs),were analyzed for each sample.Amide I region of the CH-RT-HNC group differed from the control group in cluster analysis(p=0.02).Apart from a minor variation trend in collagen maturity(p=0.07),there were no other signif-icant differences between the groups.Thus,the effect of radiochemotherapy on mandibular bone composition should be further investigated.In future trials,this study design is potential when the effects of the cancer burden and different HNC treatment modalities on jawbone composition are studied,in order to reveal ORN pathogenesis.展开更多
Hemlock woolly adelgid (Adelges Tsugae Annand, HWA) outbreaks are posing a major threat to eastern hemlock (Tsuga canadensis L. Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.) forest landscapes in the eastern ...Hemlock woolly adelgid (Adelges Tsugae Annand, HWA) outbreaks are posing a major threat to eastern hemlock (Tsuga canadensis L. Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.) forest landscapes in the eastern USA. As foundation species, hemlocks play a variety of functional roles in forest landscapes. These species usually occur as isolated canopies and mixed species in landscapes where variation in topography is extreme. Spatially explicit inventory information on HWA induced hemlock mortality at landscape scale does not exist. High resolution aerial imageries enable landscape scale assessment even at the individual tree level. Accordingly, our goal was to investigate spatial pattern and distribution of HWA induced hemlock mortality using a high resolution aerial image mosaic in the Linville River Gorge, Southern Appalachians, western North Carolina. Our study objectives were: 1) to detect dead trees within the Lower Linville River watershed;2) to estimate the area occupied by dead trees in the forest canopy surface;3) to investigate the relationship of dead hemlocks and topography;and 4) to define the spatial pattern of the dead trees. We found ca. 10,000 dead trees within the study area, occupying over 7 ha of the canopy surface with an average area of 36 m2 per dead tree. The density of the dead trees was higher in proximity to the Linville River, at higher elevations, and on northern and northwestern aspects. Spatial pattern of the dead trees was generally clustered at all spatial scales. We suggest that although the reduction in plant biomass resulting from herbivory within the landscapes is modest, impact of the clustered distribution of hemlock mortality, especially in the riparian zones, is noteworthy. Our analysis of the pattern of hemlock decline provides new means for projecting future impacts of HWA on the range of hemlock distribution in eastern North America.展开更多
文摘Radiation therapy(RT)is a treatment option for head and neck cancer(HNC),but 2%of RT patients may experience damage to the jawbone,resulting in osteoradionecrosis(ORN).The ORN can manifest years after RT exposure.Changes in the local microchemical bone quality prior to the clinical manifestation of ORN could play a key role in ORN pathogenesis.Chemical bone quality can be analyzed using Fourier transform infrared spectroscopy(FTIR),that is applied to examine the effects of cancer,chemotherapy,and RT on the quality of human man-dibular bone.Cortical mandibular bone samples were harvested from dental implant beds of 23 individuals,i.e.,patients with surgically and radiotherapeutically treated HNC(RT-HNC,n=7),surgically and radiochemotherapeutically treated HNC(CH-RT-HNC,n=3),only surgically treated HNC(SRG-HNC,n=4),and healthy controls(n=9).Infrared spectra were acquired from two representative regions of interest in cortical mandibular bone.Spectral parameters,i.e.,mineral-to-matrix ratio(MM),carbonate-to-matrix ratio(CM),carbonate-to-phosphate ratio(CP),collagen maturity(cross-linking),crystallinity,acid phosphate substitu-tion(APS),and advanced glycation end products(AGEs),were analyzed for each sample.Amide I region of the CH-RT-HNC group differed from the control group in cluster analysis(p=0.02).Apart from a minor variation trend in collagen maturity(p=0.07),there were no other signif-icant differences between the groups.Thus,the effect of radiochemotherapy on mandibular bone composition should be further investigated.In future trials,this study design is potential when the effects of the cancer burden and different HNC treatment modalities on jawbone composition are studied,in order to reveal ORN pathogenesis.
基金possible by financial aid from Graduate School in Forest Sciences(GSForest),Finnish Academy project“Centre of Excellence in Laser Scanning Research”(CoE-LaSR,decision number 272195)by the US Forest Service through USDA Forest Service cooperative agreement SRS-12-CA-11330129-077.
文摘Hemlock woolly adelgid (Adelges Tsugae Annand, HWA) outbreaks are posing a major threat to eastern hemlock (Tsuga canadensis L. Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.) forest landscapes in the eastern USA. As foundation species, hemlocks play a variety of functional roles in forest landscapes. These species usually occur as isolated canopies and mixed species in landscapes where variation in topography is extreme. Spatially explicit inventory information on HWA induced hemlock mortality at landscape scale does not exist. High resolution aerial imageries enable landscape scale assessment even at the individual tree level. Accordingly, our goal was to investigate spatial pattern and distribution of HWA induced hemlock mortality using a high resolution aerial image mosaic in the Linville River Gorge, Southern Appalachians, western North Carolina. Our study objectives were: 1) to detect dead trees within the Lower Linville River watershed;2) to estimate the area occupied by dead trees in the forest canopy surface;3) to investigate the relationship of dead hemlocks and topography;and 4) to define the spatial pattern of the dead trees. We found ca. 10,000 dead trees within the study area, occupying over 7 ha of the canopy surface with an average area of 36 m2 per dead tree. The density of the dead trees was higher in proximity to the Linville River, at higher elevations, and on northern and northwestern aspects. Spatial pattern of the dead trees was generally clustered at all spatial scales. We suggest that although the reduction in plant biomass resulting from herbivory within the landscapes is modest, impact of the clustered distribution of hemlock mortality, especially in the riparian zones, is noteworthy. Our analysis of the pattern of hemlock decline provides new means for projecting future impacts of HWA on the range of hemlock distribution in eastern North America.
