Maturational Stage (maturational + stage)

Distribution by Scientific Domains

Selected Abstracts

Heterogeneity in the Growth of the Axial and Appendicular Skeleton in Boys: Implications for the Pathogenesis of Bone Fragility in Men

Michelle Bradney
Abstract Men with spine fractures have reduced vertebral body (VB) volume and volumetric bone mineral density (vBMD). Men with hip fractures have reduced femoral neck (FN) volume and vBMD, site-specific deficits that may have their origins in growth. To describe the tempo of growth in regional bone size, bone mineral content (BMC), and vBMD, we measured bone length, periosteal and endocortical diameters, BMC, and vBMD using dual-energy X-ray absorptiometry in 184 boys aged between 7 and 17 years. Before puberty, growth was more rapid in the legs than in the trunk. During puberty, leg growth slowed while trunk length accelerated. Bone size was more advanced than BMC in all regions, being ,70% and ,35% of their predicted peaks at 7 years of age, respectively. At 16 years of age, bone size had reached its adult peak while BMC was still 10% below its predicted peak. The legs accounted for 48%, whereas the spine accounted for 10%, of the 1878 g BMC accrued between 7 and 17 years. Peripubertal growth contributed (i) 55% of the increase in leg length but 78% of the mineral accrued and (ii) 69% of the increase in spine length but 87% of the mineral accrued. Increased metacarpal and midfemoral cortical thickness was caused by respective periosteal expansion with minimal change in the endocortical diameter. Total femur and VB vBMD increased by 30,40% while size and BMC increased by 200,300%. Thus, growth builds a bigger but only slightly denser skeleton. We speculate that effect of disease or a risk factor during growth depends on the regions maturational stage at the time of exposure. The earlier growth of a regions size than mass, and the differing growth patterns from region to region, predispose to site-specific deficits in bone size, vBMD, or both. Regions further from their peak may be more severely affected by illness than those nearer completion of growth. Bone fragility in old age is likely to have its foundations partly established during growth. [source]

Regulation of embryonic endochondral ossification by Smurf2

Qiuqian Wu
Abstract Smurf2 is an E3 ubiquitin ligase that targets TGF-, receptor activated Smad2 and Smad3 for the proteasome in primary articular chondrocytes, thus stimulating their hypertrophic differentiation. Comparatively, how Smurf2 functions in growth plate chondrocytes in a developing long bone is an open question. In this study, we measured the mRNA levels of endogenous Smurf2 and type X collagen in chick growth plate at different embryonic stages to monitor the correlation between the level of Smurf2 expression and chondrocyte maturational stage. We found that high levels of Smurf2 were associated with the differentiative and proliferative stages, while Smurf2 levels were thereafter decreased as the chondrocytes matured toward hypertrophy. In addition, we injected Smurf2 -RCAS into chick wing buds at HH stage 20,23 and examined how the ectopic overexpression of Smurf2 in condensing chondrogenic mesenchyme affects the subsequent process of chondrocyte maturation and ossification during embryonic development. Histological analysis showed that overexpression of Smurf2 in a developing wing bud accelerated chondrocyte maturation and endochondral ossification, which may result from a decrease in TGF-, signaling in the infected chondrocytes with Smurf2 -RCAS. 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:704,712, 2008 [source]

An updated history of the Teratology Society

Thomas H. Shepard
BACKGROUND: The 49-year history of the Teratology Society is reviewed. An abbreviated history is outlined in table form, with listings of the Warkany Lectures, the Continuing Education Courses, and officers of the society. The original article was updated to include the years 2000 to 2010. METHODS: A year-by-year description of the events is given, including the scientific and social content of the annual meetings and changes in the business of the society, in many cases using comments from the past presidents. The valuable and unique diversity of the members is discussed and illustrated, presenting the disciplines and main research areas of the presidents. The number of submitted abstracts and the various categories are tabulated, averaging the number and type over successive periods. A significant increase in the number of abstracts dealing with epidemiology and developmental biology is evident. The society's development is compared to that of a human, and the question was asked by Shephard et al. (2000): Have we reached the maturational stage of old age or senescence, or is the society still maturing gracefully? This question needs further discussion by all the members. By 2010, many positive changes are happening to revitalize the society. RESULTS: During the past 50 years, we have developed the scientific basis to prevent birth defects caused by rubella, alcoholism, and folate deficiency, as well as other prenatal exposures. We are now taking advantage of advances in many fields to begin shaping the Teratology Society of the 21st century. CONCLUSIONS: We must now engage in political battles to obtain the resources needed to conduct further research and to implement prevention programs, as well as to provide care and rehabilitation for persons with birth defects. Birth Defects Research (Part A), 2010. 2010 Wiley-Liss, Inc. [source]

The role of melatonin in immuno-enhancement: potential application in cancer

Sandra C. Miller
Summary Melatonin, a neurohormone produced mainly by the pineal gland, is a modulator of haemopoiesis and of immune cell production and function, both in vivo and in vitro. Physiologically, melatonin is associated with T-helper 1 (Th1) cytokines, and its administration favours Th1 priming. In both normal and leukaemic mice, melatonin administration results in quantitative and functional enhancement of natural killer (NK) cells, whose role is to mediate defenses against virus-infected and cancer cells. Melatonin appears to regulate cell dynamics, including the proliferative and maturational stages of virtually all haemopoietic and immune cells lineages involved in host defense , not only NK cells but also T and B lymphocytes, granulocytes and monocytes , in both bone marrow and tissues. In particular, melatonin is a powerful antiapoptotic signal promoting the survival of normal granulocytes and B lymphocytes. In mice bearing mid-stage leukaemia, daily administration of melatonin results in a survival index of 30,40% vs. 0% in untreated mice. Thus, melatonin seems to have a fundamental role as a system regulator in haemopoiesis and immuno-enhancement, appears to be closely involved in several fundamental aspects of host defense and has the potential to be useful as an adjuvant tumour immunotherapeutic agent. [source]

Laminar organization of the developing lateral olfactory tract revealed by differential expression of cell recognition molecules

Koichiro Inaki
Abstract The projection neurons in the olfactory bulb (mitral and tufted cells) send axons through the lateral olfactory tract (LOT) onto several structures of the olfactory cortex. However, little is known of the molecular and cellular mechanisms underlying establishment of functional connectivity from the bulb to the cortex. Here, we investigated the developmental process of LOT formation by observing expression patterns of cell recognition molecules in embryonic mice. We immunohistochemically identified a dozen molecules expressed in the developing LOT and some of them were localized to subsets of mitral cell axons. Combinatorial immunostaining for these molecules revealed that the developing LOT consists of three laminas: superficial, middle, and deep. Detailed immunohistochemical, in situ hybridization, and 5-bromodeoxyuridine labeling analyses suggested that the laminar organization reflects: 1) the segregated pathways from the accessory and main olfactory bulbs, and 2) the different maturity of mitral cell axons. Mitral cell axons of the accessory olfactory bulb were localized to the deep lamina, segregated from those of the main olfactory bulb. In the main olfactory pathway, axons of mature mitral cells, whose somata is located in the apical sublayer of the mitral cell layer, were localized to the middle lamina within LOT, while those of immature mitral cells that located in the basal sublayer were complementarily localized to the superficial lamina. These results suggest that newly generated immature axons are added to the most superficial lamina of LOT successively, leading to the formation of piled laminas with different maturational stages of the mitral cell axons. J. Comp. Neurol. 479:243,256, 2004. 2004 Wiley-Liss, Inc. [source]

Abnormal differentiation of memory T cells in systemic lupus erythematosus

Ruth D. Fritsch
Objective The chemokine receptor CCR7 and the tumor necrosis factor receptor family member CD27 define 3 distinct, progressively more differentiated maturational stages of CD4 memory subpopulations in healthy individuals: the CCR7+,CD27+, the CCR7,, CD27+, and the CCR7,,CD27, populations. The goal of this study was to examine maturational disturbances in CD4 T cell differentiation in systemic lupus erythematosus (SLE), using these phenotypic markers. Methods Phenotypic analysis by flow cytometry, in vitro stimulation experiments, telomere length measurement, and determination of inducible telomerase were carried out. Results In SLE patients, significant increases of CCR7,,CD27, and CCR7,,CD27+ and a reduction of CCR7+,CD27+ CD4 memory T cells were found. In vitro stimulation of SLE T cells showed a stepwise differentiation from naive to CCR7+,CD27+ to CCR7,,CD27+ to CCR7,,CD27,; telomere length and inducible telomerase decreased in these subsets in the same progressive sequence. The in vitro proliferative response of these populations progressively declined as their susceptibility to apoptosis increased. Interestingly, a significant reduction in inducible telomerase was noted in SLE naive and CCR7+,CD27+ CD4+ memory T cells. Additionally, SLE CCR7,,CD27+ and CCR7,, CD27, CD4 memory T cells proliferated poorly in response to in vitro stimulation and underwent significantly more apoptosis than their normal counterparts. Finally, expression of CXCR4 was significantly reduced in all SLE subsets compared with normal. Conclusion Together these data indicate an increased degree of in vivo T cell stimulation in SLE, resulting in the accumulation of terminally differentiated memory T cells with a decreased proliferative capacity and an increased tendency to undergo apoptosis upon stimulation. [source]