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1.
2.
The protein–nanomaterial interface 总被引:1,自引:1,他引:0
3.
Benzene, an accepted leukemogen, has been suggested to cause other hemato- and lymphopoietic cancers. Here we review the published literature for non-Hodgkin lymphoma (NHL) and occupational exposure to benzene. Six cohorts, sixteen case–control studies and two studies of other designs were identified through keyword searches of bibliographic databases. Twenty-two of twenty-four studies found no association between NHL and ever exposed to benzene compared to never; a random-effects meta-analysis gave a pooled risk estimate of 1.11 (95% confidence interval 0.94–1.30). Our finding of no effect agrees with one of two previous meta-analyses. The other meta-analysis examined if high benzene exposure increased NHL risk but a lack of consistent exposure categories within the same metric should have precluded pooling risks by exposure level. Instead, we reviewed whether dose–response relationships existed. The best available data came from six studies where exposure was estimated from historical measurements and on the whole, no trends in risks of NHL with rising cumulative, average, peak, or duration of benzene exposure were found. NHL is a heterogeneous group of malignancies and although less well-studied, benzene was not associated with any NHL subtype. In conclusion, benzene at either low or high doses does not increase the risk of NHL. 相似文献
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Normative adontometric data are presented on a sample of 100 adult Cercopithecus aethiops(51 male, 49 female). When correlation effects among the teeth were held constant through multivariate canonical analyses,
contributions of individual tooth loci to the male-female distance were found to be similar to those isolated by univariate
means. The present study fails to support Garn’s field theory of sex dimorphism. When these patterns of sexual dimorphism
were contrasted with those of three other conspecific groups, the anterior teeth were found to show greater intrapopulation
variation than the posterior teeth. This, together with the finding that Penrose’s shape distances between the groups were
greater for anterior than postcanine teeth, provides evidence in support of Suolé’s hypothesis. The latter suggests, inter
alia, that high coefficients of variation indicate a proportionately higher environmental than hereditary contribution to
phenotypic variation. Negative correlations between tooth size and coefficients of variation suggest that tooth-size variability
is related to size rather than occlusal complexity. 相似文献
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Glycosylation of procathepsin L does not account for species molecular-mass differences and is not required for proteolytic activity. 总被引:3,自引:0,他引:3 下载免费PDF全文
Cathepsin L is a major lysosomal cysteine proteinase in mouse and human cells. Despite similar predicted molecular masses, procathepsin L in these two species migrates on SDS/polyacrylamide gels with apparent molecular masses of 39 kDa and 42 kDa respectively. To determine if glycosylation differences account for this discrepancy, and to ascertain whether glycosylation is essential for enzymic activity, mouse and human procathepsins L were expressed at high concentrations in mouse NIH 3T3 cells or in human A431 cells after DNA-mediated transfection of cloned DNAs for these enzymes. In pulse-chase studies, human procathepsin L transfectants synthesized and secreted large amounts of enzymically active 42 kDa proenzyme and processed it into 34 kDa and 26 kDa intracellular peptides, a pattern of secretion and processing similar to that seen with endogenous or transfected mouse procathepsin L. Both translation of cloned procathepsin L cDNAs in vitro and Endoglycosidase H treatment of 39 kDa mouse and 42 kDa human procathepsin L resulted in non-glycosylated proteins 2 kDa lower in molecular mass than the untreated proteins for both species. This suggests that glycosylation differences are not responsible for the molecular-mass disparity between the two species. Moreover, Endoglycosidase H-treated mouse enzyme retained full proteolytic activity, indicating that glycosylation of cathepsin L is not essential for enzymic function. 相似文献
8.
Normative odontometric data are presented on a sample of 66 adult thick-tailed bushbabies Otolemur crassicaudatus(34 male, 32 female). This species is characterized by low levels of sexual dimorphism, with univariate differences centered
on the canines and the maxillary third molar. Multivariate canonical analysis isolates a third discriminator, the maxillary
second molar. Stepwise discriminant analyses, performed after jackknifing, indicate high percentages of correct classification
(males, 79.8–81.8%;females, 81–85.2%). When variability profiles consisting of arrays of CVs are compared, males and females are found to share
similar patterns. Data for maxillary teeth offer support for Gingerich’s occlusal complexity model, while morphogenetic clusterings
within regressions of variability on tooth size conform to those previously reported in other species. These relationships
are lost in the mandibular dentition, suggesting an independence of upper from lower toothsize determination. 相似文献
9.
C L Smith C M Ewing M T Mellon S E Kane T Jain R G Shorr 《Journal of biochemical and biophysical methods》1989,19(1):51-64
HydroLink materials represent a novel family of gels composed of unique polymer matrices. The applications of HydroLink to molecular biology and, specifically, to DNA technology have been carefully investigated. Our results indicate that the HydroLink matrix developed for double-stranded DNA (dsDNA) is an excellent tool for electrophoretic separations in fixed electric fields. Excellent linear resolution from 100 to 5000 base pairs is easily achieved with good resolution albeit non-linear from 6000 to 23000 base pairs. The broad range of separation in addition to increased mechanical strength of dsDNA HydroLink represents a distinct advantage over other matrices currently used in DNA electrophoretic analysis. 相似文献
10.
Cross-linking of IgE-receptor complexes by rigid bivalent antigens greater than 200 A in length triggers cellular degranulation 总被引:2,自引:0,他引:2
We have examined the effect of cross-linking IgE-receptor complexes with variable receptor-receptor distances on the transmembrane signaling that leads to degranulation of rat basophilic leukemia cells. Linear polymers of the biotin-binding protein avidin were generated with bis biotin-1,12-diamidododecane, and a dinitrophenyl-biotin conjugate was bound at each end of the polymers to form a series of rigid bivalent haptens of well-defined length. The polymers were fractionated by size with nondenaturing PAGE, electro-eluted, and tested for their ability to stimulate degranulation of rat basophilic leukemia cells sensitized with anti-DNP IgE. We found that hexamers of avidin (of length greater than or equal to 240 A) were as effective in triggering degranulation as dimers (of length approximately 80 A), while the monomeric avidin antigen (of length approximately 40 A) elicited a poorer degranulation response from the cells. The mechanism by which aggregation of cell surface receptors can initiate signal transduction is discussed in light of these results. 相似文献