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121.
A method for analysis of elution data of proteins, obtained from Sephadex gel filtration experiments, is described. The relevant elution data from seven different proteins, with known molecular weights and Stoke's radii, were fitted into various equations relating elution parameters and molecular size parameters. It was observed that polynomial relationships represented elution data for proteins with a much greater degree of precision than linear equations. The validity of this procedure was also checked by analysing gel filtration data available in the literature and it was concluded that a better fit was obtained using polynomial relationships, provided a sufficiently large number of experimental points were available for numerical analysis. Using this method, values of 320,000 ± 7000 for the molecular weight, and (60 ± 0.4) × 10?8 cm for the Stoke's radius of Neurospora NAD-specific glutamate dehydrogenase were calculated. 相似文献
122.
Uptake and release of bilirubin by skin 总被引:2,自引:2,他引:0
Chiranjiv L. Kapoor Coimbatore R. Krishna Murti Prakash C. Bajpai 《The Biochemical journal》1973,136(1):35-43
1. Skin epithelium of albino rat, mouse and guinea pig was shown to accumulate bilirubin from a medium containing free or bound bilirubin. 2. The K(m) values for bound bilirubin were 2.22x10(-3), 1.33x10(-3) and 9.5x10(-4)m for rat, mouse and guinea pig respectively and the corresponding K(m) values for free bilirubin were 5.2x10(-4), 4.0x10(-4), 1.8x10(-4)m; the V(max.) values of bound and free bilirubin were unchanged. 3. The uptake showed saturation kinetics. Bound bilirubin was released together with serum proteins. Free bilirubin bound to skin was not released into the medium. 4. Freezing and thawing of skin epithelium did not cause any significant lowering of the uptake of bilirubin but heat-denatured skin epidermis took up only 50% of the bound bilirubin or free bilirubin taken up by control unheated skin epithelium. 5. The uptake of free and bound bilirubin was prevented by HgCl(2) but not by sodium arsenate, NaCN, NaF, cycloheximide, 2,4-dinitrophenol or iodoacetate. 6. Most of the free bilirubin was bound to the lipids or lipoprotein fraction of skin epithelium and could be extracted by solvents. 7. Rat skin showed the highest accumulation and efflux of bilirubin. 相似文献
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125.
OBJECTIVE: To evaluate the diagnostic accuracy and reliability of preoperative ultrasound (US)-guided fine needle aspiration cytology (FNAC) in the diagnosis of xanthogranulomatous cholecystitis (XGC) and coexistent lesions (carcinoma) and also to evaluate the possibility ofmissing either carcinoma or XGC on cytology. STUDY DESIGN: The cytologic diagnoses of XGC and coexistent lesions were made according to standard criteria. In a prospective, 5-year study, preoperative US-guided FNAC from 42 cases of XGC was compared with follow-up histologic diagnoses, which were available in 31 cases. When FNAC after the first aspiration showed the aspirate to be nondiagnostic, FNAC was repeated under US guidance. RESULTS: Preoperative US-guided FNAC diagnoses of XGC were made in 31 cases, for which follow-up histology was available in all cases. US-guided FNAC diagnosis ofXGC only was made in 30 cases and coexistent lesions in 1 case. Followup histology revealed 26 cases of XGC, 4 of a coexistent lesion and 1 of squamous cell carcinoma only. The overall diagnostic accuracy of preoperative US-guided FNAC was 96.77%. The overall possibility of missing XGC was 3.33% and that of carcinoma, 12.01%. CONCLUSION: Preoperative US-guided FNAC is safe, rapid, reliable, cost-effective and accurate in diagnosing XGC. However, the possibility ofcoexistent carcinoma cannot be definitely ruled out. It is therefore recommended that FNAC be performed from multiple suspicious sites under radiologic guidance. Thus, preoperative US-guided FNAC diagnosis would help in determining the urgency of treatment and also in planning the surgical procedure for gallbladder lesions. 相似文献
126.
Selection of gp41-mediated HIV-1 cell entry inhibitors from biased combinatorial libraries of non-natural binding elements. 总被引:6,自引:0,他引:6
M Ferrer T M Kapoor T Strassmaier W Weissenhorn J J Skehel D Oprian S L Schreiber D C Wiley S C Harrison 《Nature structural biology》1999,6(10):953-960
The trimeric, alpha-helical coiled-coil core of the HIV-1 gp41 ectodomain is thought to be part of a transient, receptor-triggered intermediate in the refolding of the envelope glycoprotein into a fusion-active conformation. In an effort to discover small organic inhibitors that block gp41 activation, we have generated a biased combinatorial chemical library of non-natural binding elements targeted to the gp41 core. From this library of 61,275 potential ligands, we have identified elements that, when covalently attached to a peptide derived from the gp41 outer-layer alpha-helix, contribute to the formation of a stable complex with the inner core and to inhibition of gp41-mediated cell fusion. 相似文献
127.
Vena Kapoor 《Journal of Insect Conservation》2008,12(1):53-68
Studies on the effects of tropical rainforest fragmentation and disturbance have often focussed on plants and vertebrates
such as birds and mammals and seldom on invertebrates, despite the latter being among the most biologically diverse groups
in these ecosystems. Spiders are one such group of invertebrate predators that are known to be sensitive indicators of environmental
change in tropical ecosystems. The present study assesses the spider community structure and responses to rainforest fragmentation
and degradation and conversion to shade-coffee plantations in the Anamalai hills, southern Western Ghats, India. Ten rainforest
fragments ranging in size from 11 ha to 2,600 ha under varying levels of degradation within the Indira Gandhi Wildlife Sanctuary
and private lands of the Valparai plateau, and two shade-coffee plantation sites were sampled for spiders using visual searches
along time-constrained belt transects between January and May 2005. Within a total sampled area of 5.76 ha, 4,565 individual
spiders (4,300 detections) belonging to 156 morphospecies within 21 families and 8 functional groups were recorded. The estimated
total number of understorey spider species in the study area was 192 (±5.15 SD) species, representing around 13% of the total
number of spider species so far described from India. Overall spider density, species richness, and species density showed
no trend in relation to fragment area across all sites. Specific comparisons among undisturbed sites indicated however that
high altitude sites had fewer species than mid-altitude sites and fragments had fewer species than relatively larger continuous
forest sites. In contrast to the lack of trend in overall species richness and abundance, species composition changed substantially
in relation to habitat alteration and altitude. Cluster analysis of Bray-Curtis similarities among sites in spider species
composition revealed four distinct clusters: high altitude undisturbed sites, mid-altitude disturbed sites with an undisturbed
mid altitude site, mid-altitude highly disturbed sites with a disturbed site, and shade-coffee plantation sites. Spider species,
such as Psechrus torvus and Tylorida culta, that contributed significantly to the dissimilarity between undisturbed and disturbed rainforest sites, and rainforest and
shade-coffee sites were identified that serve as useful indicators of habitat alteration. 相似文献
128.
Gustavo Palacios Mady Hornig Daniel Cisterna Nazir Savji Ana Valeria Bussetti Vishal Kapoor Jeffrey Hui Rafal Tokarz Thomas Briese Elsa Baumeister W. Ian Lipkin 《PloS one》2009,4(12)
Background
Initial reports in May 2009 of the novel influenza strain H1N1pdm estimated a case fatality rate (CFR) of 0.6%, similar to that of seasonal influenza. In July 2009, however, Argentina reported 3056 cases with 137 deaths, representing a CFR of 4.5%. Potential explanations for increased CFR included virus reassortment or genetic drift, or infection of a more vulnerable population. Virus genomic sequencing of 26 Argentinian samples representing both severe and mild disease indicated no evidence of reassortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence. Furthermore, no evidence was found for increased frequency of risk factors for H1N1pdm disease.Methods/Principal Findings
We examined nasopharyngeal swab samples (NPS) from 199 cases of H1N1pdm infection from Argentina with MassTag PCR, testing for 33 additional microbial agents. The study population consisted of 199 H1N1pdm-infected subjects sampled between 23 June and 4 July 2009. Thirty-nine had severe disease defined as death (n = 20) or hospitalization (n = 19); 160 had mild disease. At least one additional agent of potential pathogenic importance was identified in 152 samples (76%), including Streptococcus pneumoniae (n = 62); Haemophilus influenzae (n = 104); human respiratory syncytial virus A (n = 11) and B (n = 1); human rhinovirus A (n = 1) and B (n = 4); human coronaviruses 229E (n = 1) and OC43 (n = 2); Klebsiella pneumoniae (n = 2); Acinetobacter baumannii (n = 2); Serratia marcescens (n = 1); and Staphylococcus aureus (n = 35) and methicillin-resistant S. aureus (MRSA, n = 6). The presence of S. pneumoniae was strongly correlated with severe disease. S. pneumoniae was present in 56.4% of severe cases versus 25% of mild cases; more than one-third of H1N1pdm NPS with S. pneumoniae were from subjects with severe disease (22 of 62 S. pneumoniae-positive NPS, p = 0.0004). In subjects 6 to 55 years of age, the adjusted odds ratio (OR) of severe disease in the presence of S. pneumoniae was 125.5 (95% confidence interval [CI], 16.95, 928.72; p<0.0001).Conclusions/Significance
The association of S. pneumoniae with morbidity and mortality is established in the current and previous influenza pandemics. However, this study is the first to demonstrate the prognostic significance of non-invasive antemortem diagnosis of S. pneumoniae infection and may provide insights into clinical management. 相似文献129.