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Mays S 《American journal of physical anthropology》2000,112(3):349-361
Age-dependent cortical bone loss was investigated in an earlier British population. The study sample comprised female skeletons from the 18th/19th century crypt at Christ Church, Spitalfields, London. Bone loss was monitored using metacarpal radiogrammetry. Age at death was known exactly from coffin plates. Results indicated that peak cortical thickness was less than in modern subjects. Continuing periosteal apposition was evident throughout adulthood, and the rate of increase in metacarpal diameter resembled that in modern subjects. Bone loss from the endosteal surface was evident from the fifth decade onwards, and this outstripped the rate of subperiosteal gain so that there was a net loss of cortical bone with age. Cortical bone loss occurred at a similar rate to that in modern subjects. In contrast to modern populations, there was no evidence that loss of cortical bone was associated with increased propensity to fracture. The present results, together with those previously published for a British medieval skeletal assemblage, suggest that patterns of cortical bone loss in women have remained unchanged over at least the last millennium in Britain. Given the great changes in lifestyle which have occurred during this period, this suggests that lifestyle factors may be rather less important than is sometimes asserted in influencing the severity of osteoporosis, at least as far as loss of cortical bone is concerned. 相似文献
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Mays SA 《American journal of physical anthropology》2006,129(4):518-528
Age-dependent cortical bone loss in adult females from a skeletal assemblage from 3rd-4th century AD England was studied using metacarpal radiogrammetry. Results showed reduced peak cortical bone thickness compared with modern subjects, and the magnitude of cortical bone loss in older females compared with their younger counterparts was greater than that documented for a modern reference population. An elevated prevalence of fractures classically associated with osteoporosis was also observed in the over-50-year cohort. The severity of osteoporosis in this group is difficult to explain in terms of extraneous factors relating to 3rd-4th century lifestyles. Given the important genetic component in osteoporosis, the results may indicate some inherent susceptibility in this particular population to the disease, and ways in which this possibility might be further explored are suggested. 相似文献
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Mays S 《American journal of physical anthropology》2001,116(1):34-44
The effects of age and occupation on cortical bone in a group of adult males from the 18th-19th century AD skeletal collection from Christ Church Spitalfields, London, were investigated. Cortical bone was monitored using metacarpal radiogrammetry. Individual age at death was known exactly from coffin plates. Occupation for individuals was known from historical sources. Results showed that continued periosteal apposition was evident throughout adult life, but from middle age onwards this was outstripped by about 2:1 by endosteal resorption, so that there was net thinning of cortical bone. The rate of cortical thinning resembled that seen in modern European males. Cross-sectional properties, as measured by second moments of area, bore no relationship to occupation. The results may suggest that, firstly, patterns of loss of cortical bone have remained unchanged in males for at least two centuries in Britain, and secondly, that biomechanical analyses of metacarpal cortical bone may be rather insensitive indicators of intensity of manual activity. 相似文献
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Growth hormone (GH) has profound effects on linear bone growth, bone metabolism and bone mass. The GH receptor is found on the cell surface of osteoblasts and osteoclasts, but not on mature osteocytes. In vitro, GH stimulates proliferation, differentiation and extracellular matrix production in osteoblast-like cell lines. GH also stimulates recruitment and bone resorption activity in osteoclast-like cells. GH promotes autocrine/paracrine insulin-like growth factor 1 (IGF-I) production and endocrine (liver-derived) IGF-I production. Some of the GH-induced effects on bone cells can be blocked by IGF-I antibodies, while others cannot. In animal experiments, GH administration increases bone formation and resorption, and enhances cortical bone mass and mechanical strength. When GH induces linear growth, increased cancellous bone volume is seen, but an unaffected cancellous bone volume is found in the absence of linear growth. Patients with acromegaly have increased bone formation and resorption markers. Bone mass results are conflicting because many acromegalics have hypogonadism, but in acromegalics without hypogonadism, increased bone mineral density (BMD) is seen in predominantly cortical bone, and normal BMD in predominantly cancellous bone. Adult patients with growth hormone deficiency have decreased bone mineral content and BMD. GH therapy rapidly increases bone formation and resorption markers. During the first 6-12 months of therapy, declined or unchanged BMD is found in the femoral neck and lumbar spine. All GH trials with a duration of two years or more show enhanced femoral neck and lumbar spine BMD. In osteoporotic patients, GH treatment quickly increases markers for bone formation and resorption. During the first year of treatment, unchanged or decreased BMD values are found, whereas longer treatment periods report enhanced or unchanged BMD values. However, existing trials comprising relatively few patients and limited treatment periods do not allow final conclusions to be drawn regarding the effects of GH on osteoporosis during long-term treatment. 相似文献
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Effect of fibroblast growth factors 1, 2, 4, 5, 6, 7, 8, 9, and 10 on avian chondrocyte proliferation. 总被引:3,自引:0,他引:3
It has been demonstrated that fibroblast growth factor receptors are key regulators of endochondral bone growth. However, it has not been determined what fibroblast growth factor ligand(s) (FGFs) are important in this process. This study sought to determine whether FGFs 1, 2, 4, 5, 6, 7, 8, 9, and 10 were capable of stimulating avian chondrocyte proliferation in vitro. We have found that FGFs 2, 4, and 9 strongly stimulate avian chondrocyte proliferation while FGFs 6 and 8 stimulate proliferation to a lesser extent. RT-PCR indicates that FGF-2 and FGF-4 are expressed in the postnatal avian epiphyseal growth plate (EGP) while FGF-8 and FGF-9 are not. Thus, FGF-2 and FGF-4 stimulate chondrocyte proliferation and are both present in the EGP. This suggests that FGF-2 and FGF-4 may be important ligands, in vivo, for the regulation of endochondral bone growth. These observations coupled with our observation that multiple avian FGF receptors (Cek1, Cek2, Cek3, and FREK) are expressed in proliferative chondrocytes highlights the complexity of FGF signaling pathways in postnatal endochondral bone growth. 相似文献
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OBJECTIVE: To examine the effects of migration, diversity of migrant origins, commuting, and socioeconomic status on the incidence of acute lymphoblastic leukaemia in childhood. DESIGN: Poisson regression analysis of incidence rates in relation to the variables of interest. SETTING: The 403 county districts of England and Wales during 1979-85. SUBJECTS: Children aged under 15 years. RESULTS: There were significant trends in the incidence of lymphoblastic leukaemia at ages 0-4 and 5-9 years with the proportion of children in a district who had recently entered the district. While there was no consistent relation between the proportion of recent incomers in the total population of a district and its incidence rate, the combination of higher migration with greater diversity of origins or distance moved was associated with higher incidence in both age groups. Incidence increased significantly at age 0-4 with the level of employment in a district and at age 5-9 with the proportion of households with access to a car. No significant trends were found with commuting. CONCLUSIONS: The results for level of child migration and diversity of total migration provide evidence of an effect of population mixing on the incidence of childhood leukaemia which is not restricted to areas experiencing the most extreme levels of mixing. 相似文献
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Roberts P Weston S Wild B Boston C Ditchfield P Shortland AJ Pollard AM 《American journal of physical anthropology》2012,147(1):1-10
The Guizhou snub‐nosed monkey (Rhinopithecus brelichi) is a primate species endemic to the Wuling Mountains in southern China. With a maximum of 800 wild animals, the species is endangered and one of the rarest Chinese primates. To assess the genetic diversity within R. brelichi and to analyze its genetic population structure, we collected fecal samples from the wild R. brelichi population and sequenced the hypervariable region I of the mitochondrial control region from 141 individuals. We compared our data with those from the two other Chinese snub‐nosed species (R. roxellana, R. bieti) and reconstructed their phylogenetic relationships and divergence times. With only five haplotypes and a maximum of 25 polymorphic sites, R. brelichi shows the lowest genetic diversity in terms of haplotype diversity (h), nucleotide diversity (π), and average number of pairwise nucleotide differences (Π). The most recent common ancestor of R. brelichi lived ~0.36 million years ago (Ma), thus more recently than those of R. roxellana (~0.91 Ma) and R. bieti (~1.33 Ma). Phylogenetic analysis and analysis of molecular variance revealed a clear and significant differentiation among the three Chinese snub‐nosed monkey species. Population genetic analyses (Tajima's D, Fu's Fs, and mismatch distribution) suggest a stable population size for R. brelichi. For the other two species, results point in the same direction, but population substructure possibly introduces some ambiguity. Because of the lower genetic variation, the smaller population size and the more restricted distribution, R. brelichi might be more vulnerable to environmental changes or climate oscillations than the other two Chinese snub‐nosed monkey species. Am J Phys Anthropol, 2012. © 2011 Wiley Periodicals, Inc. 相似文献
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β-adrenergic receptor regulation,through cyclic AMP,of nerve growth factor expression in rat cortical and cerebellar astrocytes 总被引:4,自引:0,他引:4
1. Type 1 astrocytes prepared from 3-day rat cortex and cerebellum express the 1.3-kb nerve growth factor (NGF) mRNA and synthesize and release beta-NGF. 2. Isoproterenol (IP), a beta-adrenergic agonist, stimulates NGF mRNA content in cortical astrocytes; this increase is blocked by the beta-adrenergic antagonist propranolol but not the alpha-antagonist phenoxybenzamine. The EC50 for the effect of IP is 5 nM. 3. IP increases astrocyte cyclic AMP as does forskolin, which directly activates adenylate cyclase and also increases NGF mRNA content. Cerebellar astrocytes contain about one-third as much NGF mRNA, which can also be increased by forskolin and cyclic AMP. 4. These results suggest that CNS astrocytes can serve as a source of NGF and that the NGF gene is one of the class of cyclic AMP regulated genes. 相似文献
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Parathyroid hormone-related peptide (PTHrP)-dependent and -independent effects of transforming growth factor beta (TGF-beta) on endochondral bone formation. 总被引:5,自引:0,他引:5 下载免费PDF全文
Previously, we showed that expression of a dominant-negative form of the transforming growth factor beta (TGF-beta) type II receptor in skeletal tissue resulted in increased hypertrophic differentiation in growth plate and articular chondrocytes, suggesting a role for TGF-beta in limiting terminal differentiation in vivo. Parathyroid hormone-related peptide (PTHrP) has also been demonstrated to regulate chondrocyte differentiation in vivo. Mice with targeted deletion of the PTHrP gene demonstrate increased endochondral bone formation, and misexpression of PTHrP in cartilage results in delayed bone formation due to slowed conversion of proliferative chondrocytes into hypertrophic chondrocytes. Since the development of skeletal elements requires the coordination of signals from several sources, this report tests the hypothesis that TGF-beta and PTHrP act in a common signal cascade to regulate endochondral bone formation. Mouse embryonic metatarsal bone rudiments grown in organ culture were used to demonstrate that TGF-beta inhibits several stages of endochondral bone formation, including chondrocyte proliferation, hypertrophic differentiation, and matrix mineralization. Treatment with TGF-beta1 also stimulated the expression of PTHrP mRNA. PTHrP added to cultures inhibited hypertrophic differentiation and matrix mineralization but did not affect cell proliferation. Furthermore, terminal differentiation was not inhibited by TGF-beta in metatarsal rudiments from PTHrP-null embryos; however, growth and matrix mineralization were still inhibited. The data support the model that TGF-beta acts upstream of PTHrP to regulate the rate of hypertrophic differentiation and suggest that TGF-beta has both PTHrP-dependent and PTHrP-independent effects on endochondral bone formation. 相似文献
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This anthropometric study focuses on the histories of three important Latin American countries - Brazil, Peru, and Argentina - during the 19th century, and tests hypotheses concerning their welfare trends. While non-farm Brazil and Lima, Peru, started at relatively low height levels, Brazil made substantial progress in nutritional levels from the 1860s to the 1880s. In contrast, Lima remained at low levels. Argentinean men were tall to begin with, but heights stagnated until 1910. The only exception were farmers and landowners, who benefited from the export boom. 相似文献
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Ozen A Furman A Berber M Karatepe HO Mutlu N Sarıçoban HE Büyükgebiz B 《Helicobacter》2011,16(1):55-65
Background: It was suggested that gastric colonization with Helicobacter pylori (H. pylori) was associated with suboptimal nutrition and growth in childhood. Furthermore, several studies indicated a relationship between H. pylori colonization and alterations in the circulating levels of growth‐related molecules (GRM). Accordingly, in this study, we investigate the effect of H. pylori infection on GRMs and on the growth of healthy school children, taking into consideration the effect of their economic status (ES) and anthropometric indices of their parents. Methods: To acquire sociodemographic and anthropometric nutritional parameters and to detect H. pylori‐specific serum IgG antibodies and growth‐related molecules, we evaluated a total of 473 children attending four different primary and secondary schools in Istanbul. Subsequently, we assessed the effect of H. pylori on growth‐related parameters (weight for age SDS, height for age SDS, BMI SDS, TSF, and waist‐to‐hip ratio) and on GRMs (leptin, ghrelin, and insulin‐like growth factor‐1 (IGF‐1)), controlling for age, gender, family income, household crowding (HC), breastfeeding, maternal and paternal BMI SDS, and midparental height SDS with complex statistical models. Results: Of the 473 children (275 F/198 M, age 6–15 years; mean: 10.3 ± 0.1 years), 161 (34%) were H. pylori‐positive. The prevalence of H. pylori was significantly higher in lower economic status (ES) groups, in children living in crowded houses, and in older age groups. Using simple statistical models, we did not find any significant associations between H. pylori infection and the growth parameters. However, in complex models for height for age SDS and for weight for age SDS, there was a significant interaction between H. pylori infection status and ES. Whereas in H. pylori‐positive subjects, mid‐income family children were both taller and heavier than the low‐income group, there was no such an association in H. pylori‐negative subjects. Among biochemical parameters, only ghrelin levels were associated with H. pylori infection in all models. Leptin levels were associated with HC in girls, whereas none of the parameters was significantly associated with leptin levels in boys. For IGF‐1 levels, for boys, age and maternal BMI, and for girls, age and HC were significantly associated with IGF‐1 levels. Conclusion: We suggest that H. pylori may impair growth significantly only in susceptible children where unfavorable socioeconomic conditions facilitate its action, probably through mechanisms, at least in part, involving growth‐related molecules. 相似文献
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Setup of a bone aging experimental model in the rabbit comparing changes in cortical and trabecular bone: Morphological and morphometric study in the femur 下载免费PDF全文
Ugo E. Pazzaglia Valeria Sibilia Terenzio Congiu Francesca Pagani Marco Ravanelli Guido Zarattini 《Journal of morphology》2015,276(7):733-747
Bone aging was studied in an experimental model (rabbit femur) in three populations aged 0.5, 1.5, and 7.5 years. Cortical bone histology was compared with a data set from a 1.5‐month‐old population of an earlier published paper. From 0.5‐year‐old onward, the mean femur length did not increase further. Thereafter, the mean marrow area increased and the cortical area decreased significantly with aging. This was associated with a structural pattern transformation from plexiform to laminar and then Haversian‐like type. The distal meta‐epiphysis bone trabecular density of the oldest populations also was significantly lower in specific regions of interest (ROI). Percentage sealed primary vascular canals in laminar bone significantly increased with aging without variation of percentage sealed secondary osteons. Remodeling rate reflected by the density of cutting cones did not significantly change among the age populations. These data suggest that laminar bone vascular pattern is more functional in the fast diaphyseal expansion but not much streamlined with the renewal of blood flow during secondary remodeling. Bone aging was characterized by: 1) secondary remodeling subendosteally; 2) increment of sealed primary vascular canals number; 3) increased calcium content of the cortex; 4) cortical and trabecular bone mass loss in specific ROIs. Taken together, the present data may give a morphological and morphometric basis to perform comparative studies on experimental models of osteoporosis in the rabbit. J. Morphol. 276:733–747, 2015. © 2015 Wiley Periodicals, Inc. 相似文献