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881.
882.
In Saccharomyces cerevisiae, alpha-factor is internalized by receptor-mediated endocytosis and transported via vesicular intermediates to the vacuole where the pheromone is degraded. Using beta-tubulin and actin mutant strains, we showed that actin plays a direct role in receptor-mediated internalization of alpha-factor, but is not necessary for transport from the endocytic intermediates to the vacuole. beta-tubulin mutant strains showed no defect in these processes. In addition, cells lacking the actin-binding protein, Sac6p, which is the yeast fimbrin homologue, are defective for internalization of alpha-factor suggesting that actin filament bundling might be required for this step. The actin dependence of endocytosis shows some interesting similarities to endocytosis from the apical membrane in polarized mammalian cells. 相似文献
883.
G Egusa F Murakami C Ito Y Matsumoto S Kado M Okamura H Mori K Yamane H Hara M Yamakido 《Canadian Metallurgical Quarterly》1993,100(2):249-255
It has recently been reported that there exists a new 'RING-finger' protein family among the zinc-finger (Zf) proteins. Previously, we had isolated the mouse Mel-18 cDNA (mMel-18) encoding the nuclear RING-finger protein that exhibits an ability to bind to a nonspecific DNA column. Here, we have isolated and characterized the human Mel-18 cDNA (hMel-18) using the mMel-18 cDNA as a probe. The deduced hMel-18 protein contains 344 amino acids (38 kDa) with a RING-finger motif, a helix-loop-helix (HLH)-like structure and a Pro/Ser-rich region. The hMel-18 gene is conserved among vertebrates. Its mRNA is highly expressed in placenta, lung and kidney, but the level is low in liver, pancreas and skeletal muscle. Using in situ hybridization, we mapped hMel-18 to band q22 of chromosome 12. It is possible that the Mel-18/bmi-1 gene family represents a mammalian homologue of the Drosophila polycomb gene group. 相似文献
884.
885.
886.
Eighty-six children who completed immunization with the two trivalent poliovirus vaccines, live attenuated (OPV) and enhanced potency inactivated (EIPV), in one of four schedules (OPV-OPV-OPV, EIPV-EIPV-EIPV, EIPV-OPV-OPV, and EIPV-EIPV-OPV) at 1 year of age were monitored serologically over the subsequent 4 years and challenged with OPV at 5 years of age. Each of the immunization groups exhibited an initial 10- to 100-fold decline in neutralizing antibody to poliovirus types 1, 2, and 3 during the first 2 years of follow-up; thereafter antibody titers stabilized. The EIPV-EIPV-OPV group maintained the highest antibody levels throughout the observation period, including the response to OPV challenge at 5 years of age. These data suggest that immunization with OPV, EIPV, and combinations of the two vaccines confers long-term immunity. Optimal systemic immunity was associated with two or more doses of EIPV. 相似文献
887.
Follicular dendritic cell tumour of the liver is a recently recognized entity. To date, only two cases have been described, both in the pathology literature. Histologically, it resembles an inflammatory pseudotumour and immunohistochemical and ultrastructural studies are required for its diagnosis. The ultrasound, computed tomography and angiographic features of two cases of follicular dendritic cell tumour of the liver are described in detail. One of the patients had multiple recurrences of this tumour. The imaging features are very similar to those of hepatocellular carcinoma. As follicular dendritic cell tumour is considered to be of low-grade malignant potential, in contrast to the dismal prognosis for hepatocellular carcinoma, it is important to be able to accurately distinguish between the two types of tumour prior to initiating definitive therapy. 相似文献
888.
The original Smoking Consequences Questionnaire (SCQ; T. H. Brandon & T. B. Baker, 1991) measured college students' outcome expectancies for cigarette smoking. A version (SCQ-Adult) was needed for assessing expectancies in more typical, older, nicotine-dependent smokers. Two separate versions of the SCQ were developed and compared. Tests of construct validity provided greater support for the version comprising probability items over the version comprising subjective expected utility items. As expected, principal components analyses revealed a greater number of factors than the original SCQ suggesting that expectancies become more specific with smoking experience. All scales showed good reliability. Over the course of smoking cessation treatment, expectancies became less positive, especially for abstaining participants. Other validity tests also tended to be consistent with research on alcohol expectancies and with contemporary models of drug outcome expectancies. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
889.
The Republicans took control of both houses of Congress in November of 1994 for the 1st time in 42 yrs. Although the magnitude of the Clinton Administration's proposed Health Security Act may well have triggered fears of overcontrol, it is clear that the delivery of psychological care will be changed dramatically by the combined forces of federal and state health reform. R. J. Resnick, President of the American Psychological Association, has appointed the Task Force on Education and Training for Work in Organized Delivery Systems to look at how psychological health care is provided in the new and evolving systems, and to examine how current training programs prepare new psychologists to practice in and around organized health care systems. Dr. Resnick is similarly concerned about standardization of training, training in nontraditional areas of competence, and increased federal recognition and funding of training in psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
890.
Single-crystal YBa2Cu3O?δ (YBCO) has been made with some of the copper atoms in the copper-oxygen chains replaced by gold. The samples were made by a flux method. The gold concentration was determined by EDX (energy-dispersive X-ray spectroscopy) as a function of the nominal (i.e., flux) composition. Up to about 4.8% of all the copper atoms can be replaced by gold. The effect of the gold doping on the superconducting transition temperature (T c ) and the transition width (ΔT c ) were determined. 相似文献