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Proximal Regions (proximal + regions)
Selected AbstractsRepulsive guidance of axons of spinal sensory neurons in Xenopus laevis embryos: Roles of Contactin and notochord-derived chondroitin sulfate proteoglycansDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 7 2005Naoko Fujita An immunoglobulin superfamily neuronal adhesion molecule, Contactin, has been implicated in axon guidance of spinal sensory neurons in Xenopus embryos. To identify the guidance signaling molecules that Contactin recognizes in tailbud embryos, an in situ binding assay was performed using recombinant Contactin-alkaline phosphatase fusion protein (Contactin-AP) as a probe. In the assay of whole-mount or sectioned embryos, Contactin-AP specifically bound to the notochord and its proximal regions. This binding was completely blocked by either digestion of embryo sections with chondroitinase ABC or pretreatment of Contactin-AP with chondroitin sulfate A. When the spinal cord and the notochord explants were co-cultured in collagen gel, growing Contactin-positive spinal axons were repelled by notochord-derived repulsive activity. This repulsive activity was abolished by the addition of either a monoclonal anti-Contactin antibody, chondroitin sulfate A or chondroitinase ABC to the culture medium. An antibody that recognizes chondroitin sulfate A and C labeled immunohistochemically the notochord in embryo sections and the collagen gel matrix around the cultured notochord explant. Addition of chondroitinase ABC into the culture eliminated the immunoreactivity in the gel matrix. These results suggest that the notochord-derived chondroitin sulfate proteoglycan acts as a repulsive signaling molecule that is recognized by Contactin on spinal sensory axons. [source] Alendronate prevents femoral periprosthetic bone loss following total hip arthroplasty: Prospective randomized double-blind studyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2006Mohammad Arabmotlagh Abstract Following total hip arthroplasty (THA), femoral periprosthetic bone undergoes a remodeling process that results in bone loss in its proximal regions that may compromise the long-term outcome of THA. Periprosthetic bone loss mainly occurs during the first postoperative months. The question is whether a postoperative treatment with alendronate is effective in reducing periprosthetic bone loss and which doses and duration of treatment are required. In a 12-month prospective, randomized double-blind study, 51 patients undergoing cementless THA were treated postoperatively either with a daily dose of 20 mg alendronate for 2 months and 10 mg for 2 months thereafter (group I), with 20 mg of alendronate for 2 months and 10 mg for 4 months thereafter (group II), or treated with placebo (group III). Proximal femoral bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry (DEXA) and serum biochemical markers of bone turnover bone specific alkaline phosphatase, osteocalcin, and C-terminal telopeptides (CTX-I) were assayed. Six months of alendronate treatment significantly reduced (p,<,0.001) bone loss in proximal medial region (,10%) compared with placebo (,26%). All biochemical markers of bone turnover were suppressed by alendronate. These data suggest that alendronate administered for the first 6 postoperative months following THA was effective in preventing early periprosthetic bone loss. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1336,1341, 2006 [source] Cytochrome P450-mediated metabolism in the human gut wallJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 5 2009Kirstin Thelen Abstract Objective Although the human small intestine serves primarily as an absorptive organ for nutrients and water, it also has the ability to metabolise drugs. Interest in the small intestine as a drug-metabolising organ has been increasing since the realisation that it is probably the most important extrahepatic site of drug biotransformation. Key findings Among the metabolising enzymes present in the small intestinal mucosa, the cytochromes P450 (CYPs) are of particular importance, being responsible for the majority of phase I drug metabolism reactions. Many drug interactions involving induction or inhibition of CYP enzymes, in particular CYP3A, have been proposed to occur substantially at the level of the intestine rather than exclusively within the liver, as originally thought. CYP3A and CYP2C represent the major intestinal CYPs, accounting for approximately 80% and 18%, respectively, of total immunoquantified CYPs. CYP2J2 is also consistently expressed in the human gut wall. In the case of CYP1A1, large interindividual variation in the expression levels has been reported. Data for the intestinal expression of the polymorphic CYP2D6 are conflicting. Several other CYPs, including the common hepatic isoform CYP2E1, are expressed in the human small intestine to only a very low extent, if at all. The distribution of most CYP enzymes is not uniform along the human gastrointestinal tract, being generally higher in the proximal regions of the small intestine. Summary This article reviews the current state of knowledge of CYP enzyme expression in human small intestine, the role of the gut wall in CYP-mediated metabolism, and how this metabolism limits the bioavailability of orally administered drugs. Possible interactions between drugs and CYP activity in the small intestine are also discussed. [source] CLINICAL, MRI, AND SKIN BIOPSY FINDINGS IN SENSORY GANGLIONOPATHIESJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000A. Sghirlanzoni Unlike peripheral motor disorders, sensory disturbances are rarely diagnosed by the probable site of pathology. This approach is useful in the differential diagnosis between chronic sensory axonal neuropathies and ganglionopathies, in which routine clinical and neurophysiological evaluation alone often do not provide definite clues. Methods: Thirty patients with peripheral sensory disturbances were investigated. MRI was performed at cervical level in all cases. Four patients also underwent thoracic and lumbar MRI. Seventeen patients underwent skin biopsy at the proximal thigh and the distal leg. In 4 of them, further skin biopsies were taken at C5 dermatome and at the hand. Density of intra-epidermal nerve fibers (IENF) was quantified. Results: In 22 patients, sensory ganglionopathy was suspected. Disease was idiopathic in 7 cases; paraneoplastic in 3 cases; and associated with Sjögren, AIDS, autoimmune chronic hepatitis, and cisplatin neurotoxicity in 4 cases. One patient had a hereditary sensory autonomic neuropathy. Four patients had vitamin E deficiency and 3 patients a spinocerebellar syndrome. In 8 patients, sensory axonal neuropathy related to diabetes, alcoholism, and AIDS on antiretroviral treatment, and monoclonal gammopathy of undetermined significance was diagnosed. MRI findings: All ganglionopathy patients showed posterior columns hyperintensity on T2-weighted MRI. Conversely, MRI was negative in all axonal sensory neuropathy patients. Skin biopsy findings: In neuropathies, IENF density was significantly lower at the distal leg than at the proximal thigh, while ganglionopathies did not show any change with respect to the rostral:caudal orientation. A similar pattern of epidermal denervation was observed in the arm. Discussion: The degeneration of both central and peripheral sensory pathway in a fashion that is not length-dependent localizes the disease to T-shaped sensory neurons Early ataxia and cutaneous sensory symptoms involving the proximal regions of the body reflect this pattern of denervation and should prompt the diagnosis of ganglionopathy. This can be confirmed by T2-weighted hyperintensity in the posterior columns and a distinct pattern of IENF loss. [source] Calcaneal Tendon Regions Exhibit Different MMP-2 Activation After Vertical Jumping and Treadmill RunningTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 10 2009Olga Cristina De Mello Malheiro Abstract Increased activity of matrix metalloproteinases (MMPs) -2 and -9 was found in calcaneal tendon after physical training. However, little attention has been given to the distinct biomechanical and tissue structure of the calcaneal tendon's proximal and distal regions. Herein, we evaluated the effect of two types of physical activities on tendon morphology and matrix metalloproteinase activities in the proximal and distal regions of rat calcaneal tendon, separately. Adult male Wistar rats from control, water-adapted, vertical-jumping, and treadmill-running groups were sacrificed after 1 or 4 days of physical exercise, 6 hr after the end of that day's exercise session. Tendons were processed for histology, morphometry, and gelatin zymography. Tendons from adapted and trained animals showed active secretory cells and increased thickness, cellularity, and blood vessel volume fraction of peritendinous sheath, but without inflammatory process. In the proximal region, both pro- and active MMP-2 were increased after vertical jumping, but only pro-MMP-2 was increased after treadmill running. In contrast, in the distal region, both exercise types increased the activity of pro- and active MMP-2, especially treadmill running, which increased the active MMP-2 by about 11- and eightfold, respectively, after 1 and 4 days of training. No activity of MMP-9 was observed in either tendon region in this study. In conclusion, distal and proximal regions of calcaneal tendon exhibit differential intensities of tissue remodeling after treadmill running or vertical jumping and MMP-2, in the absence of inflammation, plays a major role in this adaptive response. Anat Rec, 2009. © 2009 Wiley-Liss, Inc. [source] Nuclear pore disassembly from endoplasmic reticulum membranes promotes Ca2+ signalling competencyTHE JOURNAL OF PHYSIOLOGY, Issue 12 2008Michael J. Boulware The functionality of the endoplasmic reticulum (ER) as a Ca2+ storage organelle is supported by families of Ca2+ pumps, buffers and channels that regulate Ca2+ fluxes between the ER lumen and cytosol. Although many studies have identified heterogeneities in Ca2+ fluxes throughout the ER, the question of how differential functionality of Ca2+ channels is regulated within proximal regions of the same organelle is unresolved. Here, we studied the in vivo dynamics of an ER subdomain known as annulate lamellae (AL), a cytoplasmic nucleoporin-containing organelle widely used in vitro to study the mechanics of nuclear envelope breakdown. We show that nuclear pore complexes (NPCs) within AL suppress local Ca2+ signalling activity, an inhibitory influence relieved by heterogeneous dissociation of nucleoporins to yield NPC-denuded ER domains competent at Ca2+ signalling. Consequently, we propose a novel generalized role for AL , reversible attenuation of resident protein activity , such that regulated AL (dis)assembly via a kinase/phosphatase cycle allows cells to support rapid gain/loss-of-function transitions in cellular physiology. [source] Immunocytological analysis of meiotic recombination in the American mink (Mustela vison)ANIMAL GENETICS, Issue 2 2009P. M. Borodin Summary Using immunolocalization of MLH1, a mismatch repair protein that marks crossover sites along synaptonemal complexes, we estimated the total length of the genetic map, the recombination rate and crossover distribution in the American mink (Mustela vison). We prepared spreads from 130 spermatocytes of five male minks and mapped 3320 MLH1 foci along 1820 bivalents. The total recombination length of the male mink genome, based on the mean number of MLH1 foci for all chromosomes, was 1327 cM. The overall recombination rate was estimated to be 0.48 cM/Mb. In all bivalents, we observed prominent peaks of MLH1 foci near the distal ends and a paucity of them near the centromeres. This indicates that genes located at proximal regions of the chromosomes should display much tighter genetic linkage than physically equidistant markers located near the telomeres. [source] | |||||||||||||