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991.
H Saitoh CA Cooke WH Burgess WC Earnshaw M Dasso 《Canadian Metallurgical Quarterly》1996,7(9):1319-1334
Ran is a small GTPase that is required for protein import, mRNA export, and the maintenance of nuclear structures. To gain a better understanding of Ran's role in the nucleus, we have sought to use Xenopus egg extracts for the purification and characterization of proteins from egg extracts bound with a high affinity to a glutathione-S-transferase-Ran fusion protein (GST-Ran). We found that GST-Ran associates specifically with at least 10 extract proteins. We determined the identifies of six Ran-interacting proteins (Rips), and found that they include RanBP2/Nup358, Nup153, Importin beta, hsc70, RCC1, and RanBP1. On the basis of peptide sequence, a seventh Rip (p88) seems to be similar but not identical to Fug1/RanGAP1, the mammalian Ran-GTPase-activating protein. Gel filtration analysis of endogenous extract proteins suggests that Importin beta acts as a primary GTP-Ran effector. Both Ran and Importin beta are coimmunoprecipitated by anti-p340RanBP2 antibodies in the presence of nonhydrolyzable GTP analogues, suggesting that Ran-Importin beta complexes interact with p340RanBP2. Two other Rips, p18 and p88, are coprecipitated with p340RanBP2 in a nucleotide-independent manner. Analysis of the Ran-GTPase pathway in Xenopus extracts allows the examination of interactions between Ran-associated proteins under conditions that resemble in vivo conditions more closely than in assays with purified components, and it thereby allows additional insights into the molecular mechanism of nuclear transport. 相似文献
992.
RJ Spina TR Miller WH Bogenhagen KB Schechtman AA Ehsani 《Canadian Metallurgical Quarterly》1996,51(3):B232-B237
The present study was designed to determine if gender affects the adaptive response to endurance exercise training of left ventricular filling dynamics in older individuals. Recently, it was shown that gender influences the cardiovascular responses to endurance exercise training in older subjects. Older men improve left ventricular systolic performance and increase maximal cardiac output in response to endurance exercise training, whereas older women do not. Twelve men (65 +/- 1 years old; mean +/- SE) and 10 women (64 +/- 1) were studied before and after 9 months of endurance exercise training. Maximal O2 uptake was determined during treadmill exercise. Left ventricular filling dynamics and ejection fraction (EF) at rest and during supine exercise were assessed by Tc-99m radionuclide ventriculography. When expressed relative to body weight, maximal O2 uptake (VO2 max) was increased by 24% (27.3 +/- 1.5 to 34.0 +/- 1.5 ml/kg/min; p < .01) in men and 27% (21.9 +/- 1.0 to 27.8 +/- 1.0 ml/kg/min; p < .01) in women in response to endurance exercise training. In men, the time-to-peak filling rate (TPFR) decreased (-19.8 +/- 6.7 ms; p < .05) during exercise at a comparable heart rate in response to training. In contrast, the change in TPFR in women (+2.7 +/- 6.0 ms) was small and insignificant. Peak filling rate (PFR) at rest and during exercise was similar before and after training in men and women. The change in left ventricular systolic reserve at a comparable heart rate from pre-to posttraining improved in men (delta EF 4 +/- 3%; p < .05), but not in women (-2 +/- 3%). The results indicate that the adaptive response of left ventricular filling dynamics to endurance exercise training is influenced by gender in older subjects. Older men show improvement in left ventricular filling dynamics, whereas older women do not. 相似文献
993.
To investigate a possible interrelationship between hypercholesterolemia and the coagulation and fibrinolytic system, the Cardiovascular Disease Risk Factor Two-Township Study in Taiwan was undertaken as a longitudinal prospective study focusing on the evolution of cardiovascular disease risk factors, with an emphasis on hemostatic factors. Hemostatic parameters measured in this study included prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, factor VIIc, factor VIIIc, antithrombin III, and plasminogen. Subjects of both sexes with hypercholesterolemia (> 6.2 mmol/L) also had significant elevations of diastolic blood pressure, plasma glucose, triglycerides, fibrinogen, and factor VIIc and reduced PT and APTT compared with subjects with lower cholesterol. The hypercholesterolemic women additionally had significant elevations of systolic blood pressure and factor VIIc. Levels of the anticoagulant factors, antithrombin III and plasminogen, were also higher in both hypercholesterolemic men and women. In men, only factor VIIIc had no statistically significant elevation. In women, only PT showed no statistical difference. Established coronary risk factors such as fibrinogen and factor VIIc showed remarkable elevations in patients of both sexes. Using Pearson correlation and multiple regression, the most significant parameter related to cholesterol level was factor VIIc. The present results show that hemostatic abnormalities do exist in patients with hypercholesterolemia, and this thrombophilic phenomenon sheds further light on the study of higher cardiovascular mortality in these subjects. 相似文献
994.
Human colostrum, the first product of lactation, has antioxidant properties and inhibits selected enzyme and bactericidal activities of human neutrophils. We examined the subsequent product of lactation, mature human milk, with respect to its antioxidant activities, its effects on neutrophil enzyme activities (myeloperoxidase, beta-glucuronidase, and lysozyme), and its effects on neutrophil bactericidal and phagocytic activities. Mature human milk displayed antioxidant characteristics similar to those of human colostrum, reducing cytochrome c and consuming H2O2. Mature milk also displayed colostrum-like characteristics in depressing neutrophil myeloperoxidase and beta-glucuronidase activities, but not in altering lysozyme activity. Neutrophil bactericidal activity against Staphylococcus aureus was depressed by both mature milk and colostrum, without dramatic effects on phagocytic activity. These data show that mature milk shares characteristics with human colostrum that may result in anti-inflammatory effects, but the magnitude of these effects is generally smaller. 相似文献
995.
996.
997.
Pharmacokinetic parameters of YH439 and its metabolites, M4, M5, and M7, were compared after iv administration of YH439 to rats (1-10 mg/kg), rabbits (1-10 mg/kg), and dogs (1-20 mg/kg) and oral administration of YH439 to rats (50-500 mg/kg) and dogs (0.5-2 g per whole body weight). After oral administration of YH439 to rats, the F values were 3.67, 1.33, and 0.859% for YH439 oral doses of 100, 300, and 500 mg/kg, respectively. However, the F value increased significantly, 21.2%, after oral administration of YH439-contained mixed micelles (10 mg as free YH439) to rats due to increased water solubility of YH439. Species differences in the pharmacokinetics of YH439 and its metabolites were found. First, M7 was detected in both plasma and urine after both iv and oral administration of YH439 to dogs, whereas it was detected neither in rats nor in rabbits, indicating that considerable amount of M7 was formed from YH439 only in dogs. Second, the AUC (or AUC0-->t) ratios of M4 to YH439 after iv administration of YH439 were 24.6-31.3, 42.2-49.2, and 2200-7640% for rats, rabbits, and dogs, respectively, indicating that formation of M4 after iv administration of YH439 was maximal in dogs. Third, the AUC (or AUC0-->t) ratios of M5 to YH439 after iv administration of YH439 were 103-127, 2.93-3.31, and 92.4-158% for rats, rabbits, and dogs, respectively, indicating that formation of M5 after iv administration of YH439 was minimal in rabbits. 相似文献
998.
999.
SE Schonfeld DS Brandes VL Freckleton RE Gillis WH Heisler RG Hunt 《Canadian Metallurgical Quarterly》1996,24(7):29-40
This article presents the results of a survey of dental auxiliaries conducted by the California Dental Association's Council on Education and Professional Relations. The survey found that a surprisingly high number of dental assistants (56 percent) and hygienists (42 percent) are considering whether to remain in the dental health care field, stated reasons for this include lack of paid benefits and little opportunity for career growth. The results also suggest, however, that if the perceived deficiencies in these areas were addressed, RDAs and RDHs might remain in the profession. 相似文献
1000.
EM van Lieshout MF Knapen WP Lange EA Steegers WH Peters 《Canadian Metallurgical Quarterly》1998,13(5):1380-1386
Glutathione S-transferases (GST) are a family of enzymes involved in the detoxification of xenobiotics. In humans, GST are divided into four different classes, alpha, mu, pi and theta, with partly overlapping substrate specificity and a tissue-specific expression pattern. We studied the cellular distribution of GST alpha and pi in a variety of human embryonic organs obtained from an extra-uterine monozygotic twin pregnancy at 8 weeks' gestational age. Tissues were fixed in 4% paraformaldehyde and embedded in paraffin. Three 4 microm thick sections were used, one for routine haematein and eosin staining, the others for immunohistochemical determination using monoclonal and polyclonal antibodies against GST alpha and pi, respectively. Both GST alpha and pi were present in hepatocytes, gastrointestinal epithelium, adrenal gland medulla, and tela chorioidea in the telencephalon. GST pi, but not alpha, was found in the epithelium of pancreatic and pulmonary glands, trachea, nephrons and urinary collecting ducts, as well as in the pia mater of the telencephalon and in developing nerve tissue in the gastrointestinal muscularis mucosae. In summary, we have demonstrated that immunoreactive protein for both GST alpha and pi is expressed in the human embryo at 8 weeks' gestational age. The early expression of GST alpha and pi in the epithelia of the urinary and digestive tracts and the respiratory system supports the importance of GST in the detoxification of potentially toxic or carcinogenic compounds. Our results suggest that the embryo itself is capable of detoxifying noxious compounds that are generated intracellularly or that cross the trophoblastic tissue. 相似文献