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41.
The microbial quality of raw fillets of aquacultured catfish, salmon, tilapia, and trout was evaluated. A total of 272 fillets from nine local and nine Internet retail markets were tested. Mean values were 5.7 log CFU/g for total aerobic mesophiles, 6.3 log CFU/g for psychrotrophs, and 1.9 log most probable number (MPN) per gram for coliforms. Differences in these microbial levels between the two kinds of markets and among the four types of fish were not significant (P > 0.05), except that Internet trout fillets had about 0.8-log higher aerobic mesophiles than did trout fillets purchased locally. Although Escherichia coli was detected in 1.4, 1.5, and 5.9% of trout, salmon, and tilapia, respectively, no sample had > or = 1.0 log MPN/g. However, E. coli was found in 13.2% of catfish, with an average of 1.7 log MPN/g. About 27% of all fillets had Listeria spp., and a positive correlation between the prevalence of Listeria spp. and Listeria monocytogenes was observed. Internet fillets had a higher prevalence of both Listeria spp. and L. monocytogenes than did those fillets purchased locally. L. monocytogenes was present in 23.5% of catfish but in only 5.7, 10.3, and 10.6% of trout, tilapia, and salmon, respectively. Salmonella and E. coli O157 were not found in any sample. A follow-up investigation using catfish operation as a model revealed that gut waste exposed during evisceration is a potential source of coliforms and Listeria spp.  相似文献   
42.
BACKGROUND & AIMS: Combining endoscopic sclerotherapy with ligation has been proposed to hasten variceal eradication. A randomized trial was performed comparing combination ligation plus sclerotherapy with ligation alone in patients with major bleeding from esophageal varices. METHODS: Forty-one patients were randomly assigned to receive ligation or ligation plus 1 mL 1.5% tetradecyl injected just above each band. Treatment was repeated weekly until varices were eradicated. Repeat endoscopy was performed for rebleeding and every 3 months after eradication. RESULTS: No significant differences were found between combined therapy and ligation in rebleeding (29% vs. 30%), blood transfused (3.1 +/- 1.1 vs. 2.0 +/- 0.8 U), hospital days (9.3 +/- 2.1 vs. 7.5 +/- 1.2), complications (29% vs. 10%), or deaths (14% vs. 15%) during a mean follow-up period of 28 weeks. Combined therapy required significantly more sessions to achieve eradication (4.9 +/- 0.6 vs. 2.7 +/- 0.4) and greater time per treatment session (18.3 +/- 1.7 vs. 13.3 +/- 0.5 minutes). CONCLUSIONS: Combined ligation plus sclerotherapy does not reduce the number of treatment sessions required for variceal eradication as compared with ligation alone. Combined therapy lengthens the time required for treatment without improving efficacy or decreasing complications. Thus, combined ligation and sclerotherapy should not be used to treat patients with bleeding esophageal varices.  相似文献   
43.
We present a quantum algorithm which identifies with certainty a hidden subgroup of an arbitrary finite group G in only a polynomial (in log|G|) number of calls to the oracle. This is exponentially better than the best classical algorithm. However our quantum algorithm requires exponential time, as in the classical case. Our algorithm utilizes a new technique for constructing error-free algorithms for non-decision problems on quantum computers.  相似文献   
44.
Ultimate load capacity of slender injection piles in soft soils. Small diameter driven injection piles are applied as a low cost foundation element for many years. They reach extremly high slenderness and tend to buckling behaviour. Some recent damage cases show that the bearing capacity is frequently overestimated. The design codes do not give evidences for the estimation of the ultimate load capacity in detail. The purpose of this paper is to show a practical method of analysis which includes the essential input parameters of apparent cohesion intercept and pile imperfection as well as the elastoplastic properties of pile material and soil.  相似文献   
45.
Insights into structure-function relations of many proteins opens the possibility of engineering peptides to selectively interfere with a protein's activity. To facilitate the use of peptides as probes of cellular processes, we have developed caged peptides whose influence on specific proteins can be suddenly and uniformly changed by near-UV light. Two peptides are described which, on photolysis of a caging moiety, block the action of calcium-calmodulin or myosin light chain kinase (MLCK). The efficacy of theses peptides is demonstrated in vitro and in vivo by determining their effect before and after photolysis on activities of isolated enzymes and cellular functions known to depend on calcium-calmodulin and MLCK. These caged peptides each were injected into motile, polarized eosinophils, and when exposed to light promptly blocked cell locomotion in a similar manner. The results indicate that the action of calcium-calmodulin and MLCK, and by inference myosin II, are required for the ameboid locomotion of these cells. This methodology provides a powerful means for assessing the role of these and other proteins in a wide range of spatio-temporally complex functions in intact living cells.  相似文献   
46.
Previously, we have reported that neutralization of surface lymphotoxin (LT-alphabeta) in mice which expressed an LT-beta receptor-Fc fusion protein, driven by the cytomegalovirus promoter, resulted in an array of anatomic abnormalities. We now report that mice which express a tumor necrosis factor (TNF) receptor p60-Fc fusion protein (which neutralizes TNF and soluble LT-alpha3 activity) develop unique lymphoid abnormalities. Our data demonstrate that some aspects of peripheral lymphoid organ development require both surface LT-alphabeta and TNF interacting with their specific receptors. However, these related cytokines are also capable of signaling distinct developmental events. Splenic MAdCAM-1 expression, follicular dendritic cell localization and normal Peyer's patch development all require both surface LT-alphabeta and TNF activity. Marginal zone formation and splenic B cell localization primarily require surface LT-alphabeta-LT-beta receptor interactions. Primary follicle formation was dependent upon TNF receptor(s) engagement. Interestingly spleen, lymph nodes and Peyer's patches from TNF receptor p60-Fc-expressing mice all develop different abnormalities, suggesting distinct pathways of development in these lymphoid organs. Thymus development appears to be independent of these signaling pathways. These results demonstrate that TNF and LT are crucial for normal peripheral, but not central lymphoid organ development.  相似文献   
47.
A new allelic series at the underwhite gene is described. Three of the alleles in the series--uw, uwd, and Uwdbr--arose as spontaneous mutations on different genetic backgrounds at The Jackson Laboratory. We report here the visible phenotypes and dominance hierarchy of these alleles, all of which are defined by a reduction of pigmentation in both eye and coat color. Electron microscopic analysis of retinal epithelium suggests that the primary defect is in the melanosome. The degree of severity of melanosome anomalies in the retina correlates with the degree of hypopigmentation in the coat. The perturbed gene and its gene product are unknown. We show that the uw locus is genetically distinct from Myo10, a suggested candidate gene for this mutation.  相似文献   
48.
We compared reflex responses to static handgrip at 30% maximal voluntary contraction (MVC) in 10 women (mean age 24.1 +/- 1.7 yr) during two phases of their ovarian cycle: the menstrual phase (days 1-4) and the follicular phase (days 10-12). Changes in muscle sympathetic nerve activity (MSNA; microneurography) in response to static exercise were greater during the menstrual compared with follicular phase (phase effect P = 0.01). Levels of estrogen were less during the menstrual phase (75 +/- 5.5 vs. 116 +/- 9.6 pg/ml, days 1-4 vs. days 10-12; P = 0.002). Generated tension did not explain differences in MSNA responses (MVC: 29.3 +/- 1.3 vs. 28.2 +/- 1.5 kg, days 1-4 vs. days 10-12; P = 0.13). In a group of experiments with the use of 31P-NMR spectroscopy, no phase effect was observed for H+ and H2PO-4 concentrations (n = 5). During an ischemic rhythmic handgrip paradigm (20% MVC), a phase effect was not observed for MSNA or H+ or H2PO-4 concentrations, suggesting that blood flow was necessary for the expression of the cycle-related effect. The present studies suggest that, during static handgrip exercise, MSNA is increased during the menstrual compared with the follicular phase of the ovarian cycle.  相似文献   
49.
PURPOSE: To determine the toxicities, pharmacokinetics, and recommended doses of the topoisomerase I inhibitor, topotecan, in patients with varying degrees of renal excretory dysfunction. PATIENTS AND METHODS: Fourteen patients with normal renal function [creatinine clearance (CrCl) > or = 60 mL/min] and 28 patients with varying degrees of renal dysfunction were treated with topotecan 0.4 to 2.0 mg/m2/d as a 30-minute infusion for 5 consecutive days every 3 weeks. Plasma and urine samples were obtained to determine the disposition of topotecan. RESULTS: In patients with mild renal dysfunction (CrCl = 40 to 59 mL/min), dose-limiting hematologic toxicity was observed in three of eight patients receiving topotecan 1.0 mg/m2/d and in two of five patients receiving topotecan 1.5 mg/m2/d. In patients with moderate renal dysfunction (CrCl = 20 to 39 mL/min), dose-limiting hematologic toxicity was observed in three of eight patients who received topotecan 0.5 mg/m2/d, and in two of four patients receiving topotecan 1.0 mg/m2/d; these events were more frequently observed in extensively pretreated patients. Pharmacokinetic analyses showed significant correlations between CrCl and the plasma clearance of both total topotecan [Spearman's correlation coefficient (r2) = 0.65, P = .00001] and topotecan lactone (r2 = 0.65, P = .00003). Mean systemic plasma clearance of total topotecan was significantly reduced in patients with mild (P = .04) and moderate (P = .00006) renal dysfunction. There was no evidence of changes in the pharmacodynamic relationship between topotecan exposure (AUC) and myelotoxicity. CONCLUSION: Dose adjustments are required in patients with moderate, but not mild, renal impairment. For patients with moderate renal dysfunction, the recommended starting dose of topotecan is 0.75 mg/m2/d for 5 days every 3 weeks. Moreover, extensively pretreated patients need further dose reductions.  相似文献   
50.
The segmentation of MRI scans of patients with white matter lesions (WML) is difficult because the MRI characteristics of WML are similar to those of gray matter. Intensity-based statistical classification techniques misclassify some WML as gray matter and some gray matter as WML. We developed a fast elastic matching algorithm that warps a reference data set containing information about the location of the gray matter into the approximate shape of the patient's brain. The region of white matter was segmented after segmenting the cortex and deep gray matter structures. The cortex was identified by using a three-dimensional, region-growing algorithm that was constrained by anatomical, intensity gradient, and tissue class parameters. White matter and WML were then segmented without interference from gray matter by using a two-class minimum-distance classifier. Analysis of double-echo spin-echo MRI scans of 16 patients with clinically determined multiple sclerosis (MS) was carried out. The segmentation of the cortex and deep gray matter structures provided anatomical context. This was found to improve the segmentation of MS lesions by allowing correct classification of the white matter region despite the overlapping tissue class distributions of gray matter and MS lesion.  相似文献   
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