排序方式: 共有58条查询结果,搜索用时 15 毫秒
1.
Effect of postnatal development on calcium currents and slow charge movement in mammalian skeletal muscle 总被引:16,自引:3,他引:13 下载免费PDF全文
Single- (whole-cell patch) and two-electrode voltage-clamp techniques were used to measure transient (Ifast) and sustained (Islow) calcium currents, linear capacitance, and slow, voltage-dependent charge movements in freshly dissociated fibers of the flexor digitorum brevis (FDB) muscle of rats of various postnatal ages. Peak Ifast was largest in FDB fibers of neonatal (1-5 d) rats, having a magnitude in 10 mM external Ca of 1.4 +/- 0.9 pA/pF (mean +/- SD; current normalized by linear fiber capacitance). Peak Ifast was smaller in FDB fibers of older animals, and by approximately 3 wk postnatal, it was so small as to be unmeasurable. By contrast, the magnitudes of Islow and charge movement increased substantially during postnatal development. Peak Islow was 3.6 +/- 2.5 pA/pF in FDB fibers of 1-5-d rats and increased to 16.4 +/- 6.5 pA/pF in 45-50-d-old rats; for these same two age groups, Qmax, the total mobile charge measurable as charge movement, was 6.0 +/- 1.7 and 23.8 +/- 4.0 nC/microF, respectively. As both Islow and charge movement are thought to arise in the transverse-tubular system, linear capacitance normalized by the area of fiber surface was determined as an indirect measure of the membrane area of the t-system relative to that of the fiber surface. This parameter increased from 1.5 +/- 0.2 microF/cm2 in 2-d fibers to 2.9 +/- 0.4 microF/cm2 in 44-d fibers. The increases in peak Islow, Qmax, and normalized linear capacitance all had similar time courses. Although the function of Islow is unknown, the substantial postnatal increase in its magnitude suggests that it plays an important role in the physiology of skeletal muscle. 相似文献
2.
Molecular evolution of voltage-sensitive ion channel genes: on the origins of electrical excitability 总被引:14,自引:0,他引:14
We have analyzed nucleic acid and amino acid sequence alignments of a
variety of voltage-sensitive ion channels, using several methods for
phylogenetic tree reconstruction. Ancient duplications within this family
gave rise to three distantly related groups, one consisting of the Na+ and
Ca++ channels, another the K+ channels, and a third including the cyclic
nucleotide-binding channels. A series of gene duplications produced at
least seven mammalian homologues of the Drosophila Shaker K+ channel;
clones of only three of these genes are available from all three mammalian
species examined (mouse, rat, and human), pointing to specific genes that
have yet to be recovered in one or another of these species. The
Shaw-related K+ channels and the Na+ channel family have also undergone
considerable expansion in mammals, relative to flies. These expansions
presumably reflect the needs of the high degree of physiological and
neuronal complexity of mammals. Analysis of the separate domains of the
four-domain channels (Ca++ and Na+) supports their having evolved by two
sequential gene duplications and implies the historical existence of a
functional two-domain channel.
相似文献
3.
Prashant G. Bhat Ajay M. V. Kumar Balaji Naik Srinath Satyanarayana Deepak KG Sreenivas A. Nair Suryakanth MD Einar Heldal Donald A. Enarson Anthony J. Reid 《PloS one》2013,8(12)
Background
Severe acute malnutrition (SAM) is the most serious form of malnutrition affecting children under-five and is associated with many infectious diseases including Tuberculosis (TB). In India, nutritional rehabilitation centres (NRCs) have been recently established for the management of SAM including TB. The National TB Programme (NTP) in India has introduced a revised algorithm for diagnosing paediatric TB. We aimed to examine whether NRCs adhered to these guidelines in diagnosing TB among SAM children.Methods
A cross-sectional study involving review of records of all SAM children identified by health workers during 2012 in six tehsils (sub-districts) with NRCs (population: 1.8 million) of Karnataka, India.Results
Of 1927 identified SAM children, 1632 (85%) reached NRCs. Of them, 1173 (72%) were evaluated for TB and 19(2%) were diagnosed as TB. Of 1173, diagnostic algorithm was followed in 460 (37%). Among remaining 763 not evaluated as per algorithm, tuberculin skin test alone was conducted in 307 (41%), chest radiography alone in 99 (13%) and no investigations in 337 (45%). The yield of TB was higher among children evaluated as per algorithm (4%) as compared to those who were not (0.3%) (OR: 15.3 [95%CI: 3.5-66.3]). Several operational challenges including non-availability of a full-time paediatrician, non-functioning X-ray machine due to frequent power cuts, use of tuberculin with suboptimal strength and difficulties in adhering to a complex diagnostic algorithm were observed.Conclusion
This study showed that TB screening in NRCs was sub-optimal in Karnataka. Some children did not reach the NRC, while many of those who did were either not or sub-optimally evaluated for TB. This study pointed to a number of operational issues that need to be addressed if this collaborative strategy is to identify more TB cases amongst malnourished children in India. 相似文献4.
Cytoplasmic localization of BAG-1 in leukoplakia and carcinoma of the tongue: correlation with p53 and c-erbB2 in carcinoma 总被引:1,自引:0,他引:1
Vora HH Mehta SV Shah KN Brahmbhatt BV Desai NS Shukla SN Shah PM 《The International journal of biological markers》2007,22(2):100-107
BACKGROUND: The present study evaluated the clinical significance of BAG-1, an antiapoptotic protein, in leukoplakia and carcinoma of the tongue. METHODS: BAG-1 expression was evaluated by immunohistochemistry in paraffin-embedded tissues of leukoplakia (n=25) and carcinoma of the tongue (n=61). RESULTS: Cytoplasmic expression was predominantly seen in 80% and 70% of patients with leukoplakia and carcinoma, respectively. BAG-1 expression was found to be significantly lower in tobacco users than in non-tobacco users. BAG-1 expression in tobacco-using leukoplakia and carcinoma patients was compared by grouping the carcinoma patients according to lymph node status and disease stage. Carcinoma patients with tumor-positive lymph nodes had significantly lower BAG-1 expression than patients with negative lymph nodes and leukoplakia. Further, a trend towards an inverse correlation was observed with p53 and c-erbB2. In univariate and multivariate survival analysis, patient subgroups with 2+ or 3+ marker positivity (BAG-1 negativity, p53 and c-erbB2 positivity) had a reduced overall survival compared with patient subgroups with 1+ marker positivity or negativity. CONCLUSION: BAG-1 negativity in association with p53 and c-erbB2 positivity identified a subgroup of tongue cancer patients with an aggressive phenotype. Hence, an antiapoptotic protein, BAG-1, was found to be down-regulated in chewing-tobacco-mediated tongue carcinogenesis. 相似文献
5.
Baur P Martin FP Gruber L Bosco N Brahmbhatt V Collino S Guy P Montoliu I Rozman J Klingenspor M Tavazzi I Thorimbert A Rezzi S Kochhar S Benyacoub J Kollias G Haller D 《Journal of proteome research》2011,10(12):5523-5535
The underlying biochemical consequences of inflammatory bowel disease (IBD) on the systemic and gastrointestinal metabolism have not yet been fully elucidated but could help to better understand the disease pathogenesis and to identify tissue-specific markers associated with the different disease stages. Here, we applied a metabonomic approach to monitor metabolic events associated with the gradual development of Crohn's disease (CD)-like ileitis in the TNF(ΔARE/WT) mouse model. Metabolic profiles of different intestinal compartments from the age of 4 up to 24 weeks were generated by combining proton nuclear magnetic resonance ((1)H NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS). From 8 weeks onward, mice developed CD similar to the immune and tissue-related phenotype of human CD with ileal involvement, including ileal histological abnormalities, reduced fat mass and body weight, as well as hallmarks of malabsorption with higher energy wasting. The metabonomic approach highlighted shifts in the intestinal lipid metabolism concomitant to the histological onset of inflammation. Moreover, the advanced disease status was characterized by a significantly altered metabolism of cholesterol, triglycerides, phospholipids, plasmalogens, and sphingomyelins in the inflamed tissue (ileum) and the adjacent intestinal parts (proximal colon). These results describe different biological processes associated with the disease onset, including modifications of the general cell membrane composition, alteration of energy homeostasis, and finally the generation of inflammatory lipid mediators. Taken together, this provides novel insights into IBD-related alterations of specific lipid-dependant processes during inflammatory states. 相似文献
6.
Brahmbhatt MM Trivedi PJ Dalal EN Patel DM Purani SS Shukla SN Shah PM Patel PS 《Journal of the Association of Genetic Technologists》2011,37(2):69-75
Aims: Variant translocations involving 9q, 22q and at least one additional genomic locus occur in 5-10% of the patients with chronic myeloid leukemia (CML). The mechanisms for the formation of these variant translocations are not fully characterized. Here we report CML cases presenting a variant translocation indicating two-step mechanism with rare/novel chromosomal rearrangement. Methods: Karyotype analysis was performed on metaphases obtained through short-term cultures of bone marrow and blood. Detection of BCR-ABL fusion gene was performed using dual-color dual-fusion (D-FISH) and extra signal (ES) translocation probes. BAC-FISH was also carried out. Results: In Patient 1, the third partner chromosome was der(11)(p15) with a 2F2G1R signal pattern, which is an unusual signal pattern with the two-step mechanism. Patients 2 and 3 showed typical positive (2F1G1R) signal pattern. In Patient 2, both the chromosome 22s were involved in variant formation. The second fusion was observed below the BCR gene of the second homologue. In Patient 3 the third chromosome was der(13)(q14). The fourth patient showed a variant pattern with BCR/ABL-ES probe involving der(X)(q13) region. Conclusion: The presence of different rearrangements of both 9q34 and 22q11 regions highlights the genetic heterogeneity of this subgroup of CML. In each case with variants, further studies with FISH, BAC-FISH or more advanced technique such as microarray should be performed. Future studies should be performed to confirm the presence of true breakpoint hot spots and assess their implications in CML with variant Ph. 相似文献
7.
Nagy K Brahmbhatt VV Berdeaux O Bretillon L Destaillats F Acar N 《Journal of lipid research》2012,53(4):776-783
The objective of this work was to detect and identify phosphatidylserine plasmalogen species in human ocular neurons represented by the retina and the optic nerve. Plasmalogens (vinyl-ether bearing phospholipids) are commonly found in the forms of phosphatidylcholine and phosphatidylethanolamine in numerous mammalian cell types, including the retina. Although their biological functions are unclear, the alteration of cellular plasmalogen content has been associated with several human disorders such as rhizomelic chondrodysplasia punctata Type 2 and primary open-angle glaucoma. By using liquid chromatography coupled to high-resolution and tandem mass spectrometry, we have identified for the first time several species of phosphatidylserine plasmalogens, including atypical forms having moieties with odd numbers of carbons and unsaturation in sn-2 position. Structural elucidation of the potential phosphatidylserine ether linked species was pursued by performing MS(3) experiments, and three fragments are proposed as marker ions to deduce which fatty acid is linked as ether or ester on the glycerol backbone. Interpretation of the fragmentation patterns based on this scheme enabled the assignment of structures to the m/z values, thereby identifying the phosphatidylserine plasmalogens. 相似文献
8.
9.
Gohil VM Brahmbhatt KG Loiseau PM Bhutani KK 《Bioorganic & medicinal chemistry letters》2012,22(12):3905-3907
β-carbolines from various natural and synthetic sources have been known to show diverse biological activities. As a part of our current ongoing project to search for potent natural product-derived anti-leishmanial compounds, we have synthesized a series of substituted 1-aryl-β-carboline derivatives. A total of 22 compounds were synthesized and tested in vitro against Leishmania donovani, out of which 6 compounds (4, 5, 10, 11, 19 and 22) showed notably more activity than the standard miltefosine (IC(50) 12.07±0.82 μM), with compound 4 being the most potent (IC(50) 2.16±0.26 μM). 相似文献
10.
John Ellis Sumir Brahmbhatt Daniel Desmond Brian Ching Jordanna Hostler 《Journal of medical case reports》2018,12(1):375