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81.
82.
The presence of epidermal-growth-factor receptors (EGFR) and of its ligands (TGFalpha and amphiregulin) in breast-cancer tissues suggests that they play a paracrine/autocrine role in tumor growth or progression. This hypothesis was tested on 3 cell lines, S2T2, NS2T2A and NS2T2A1. These epithelial cells are derived from a normal human breast-epithelial-cell culture transformed by SV40-T Ag, are of the same clonal origin, have respectively increasing levels of EGFR, TGFalpha, amphiregulin and of thymidine-kinase activity associated with increasing tumorigenic potential in nude mice (tumor intake and tumor volume). The monoclonal antibody MAb 425, which blocks ligands interaction with EGFR, reduced by more than 90% anchorage-independent growth of the most tumorigenic cells, NS2T2A1. Another anti-EGFR MAb, 528, reduced to 25% of controls the mean tumor mass after NS2T2A1 grafting in mice. Anti-sense RNA expression of EGFR in these cells confirmed the importance of this receptor in tumor progression, since it reduced significantly the tumor volume and tumor weight of NS2T2A1 cells to 16% of those in mock-transfected control cells.  相似文献   
83.
Low-temperature (LT) induced genes of the Wcs120 family in wheat (Triticum aestivum) were mapped to specific chromosome arms using Western and Southern blot analysis on the ditelocentric series in the cultivar Chinese Spring (CS). Identified genes were located on the long arms of the homoeologous group 6 chromosomes of all 3 genomes (A, B, and D) of hexaploid wheat. Related species carrying either the A, D, or AB genomes were also examined using Southern and Western analysis with the Wcs120 probe and the WCS120 antibody. All closely related species carrying one or more of the genomes of hexaploid wheat produced a 50 kDa protein that was identified by the antibody, and a Wcs120 homoeologue was detected by Southern analysis in all species. In the absence of chromosome arm 6DL in hexaploid CS wheat no 50 kDa protein was produced and the high-intensity Wcs120 band was missing, indicating 6DL as the location of Wcs120 but suggesting silencing of the Wcs120 homoeologue in the A genome. Levels of proteins that cross-reacted with the Wcs120 antibody and degrees of cold tolerance were also investigated in the Chinese Spring/Cheyenne (CS/CNN) chromosome substitution series. CNN chromosome 5A increased the cold tolerance of CS wheat. Densitometry scanning of Western blots to determine protein levels showed that the group 5 chromosome 5A had a regulatory effect on the expression of the Wcs120 gene family located on the group 6 chromosomes of all three hexaploid wheat genomes.  相似文献   
84.
The mitochondrial uncoupling protein (UCP) in the mitochondrial inner membrane of mammalian brown adipose tissue generates heat by uncoupling oxidative phosphorylation. This process protects against cold and regulates energy balance. Manipulation of thermogenesis could be an effective strategy against obesity. Here we determine the role of UCP in the regulation of body mass by targeted inactivation of the gene encoding it. We find that UCP-deficient mice consume less oxygen after treatment with a beta3-adrenergic-receptor agonist and that they are sensitive to cold, indicating that their thermoregulation is defective. However, this deficiency caused neither hyperphagia nor obesity in mice fed on either a standard or a high-fat diet. We propose that the loss of UCP may be compensated by UCP2, a newly discovered homologue of UCP; this gene is ubiquitously expressed and is induced in the brown fat of UCP-deficient mice.  相似文献   
85.
86.
We report here that human immunodeficiency virus type 2 (HIV-2) envelope glycoprotein (gp105), but not HIV-1 gp120, can bind to CD8 molecules as well as to CD4 molecules on human T cells. This phenomenon may lead to differences in the life cycles of HIV-1 and HIV-2, and it may be related to the differences in disease manifestations of HIV-1 and HIV-2 infection, including longer survival of HIV-2-infected patients.  相似文献   
87.
To examine the relationship between society stress and peptic ulcer perforation, time-trend analysis was performed on the annual incidence of perforated peptic ulcer per 100,000 population in Hong Kong during the years 1962-85, when Hong Kong, as a developing city, went through significant socio-economic and political changes, and the trend was correlated with specially designed and validated society stress scores estimated annually during the same period. The society stress scores were derived independently by two expert panels blinded to the purpose of the study, one selecting and categorizing negative news events for Hong Kong during this period, and the other weighing the categories and scoring the impact of the news on Hong Kong. The incidence of perforation increased significantly during the years and manifested three distinct peaks, which coincided with the worst economic recession in Hong Kong, the influx of mainlander Chinese and Vietnamese boat people, and the Sino-British negotiation on the sovereignty of Hong Kong after 1997. Both linear and autoregression analysis, the latter taking into consideration point fluctuations in rates, showed that perforation rates correlated significantly with the society stress scores (r = 0.57, P < 0.002). The peak effects and the significant correlations indicate that an association exists between society stress and peptic ulcer perforation, and suggest that chronic society stress plays an important role in the aetiology of this condition, although the relatively low r value also suggests the presence of other aetiological factors.  相似文献   
88.
Immunoreactivity of sera obtained in 1996 from HIV-1-infected intravenous narcomaniacs from an epidemic focus in Gomel region, Belarus, is studied with a panel of 10-16-component synthetic peptides simulating apical epitope of surface glycoprotein gp120 V3 loop of HIV-1 variants. Comparative analysis of resultant spectra with representative immunoreactivity spectra of sera from a sampling of HIV-1-positive sera collected in 1986-1997 in different regions of the former USSR demonstrated a high homogeneity of immunoreactivity spectra of sera from Gomel region. Serotypes of HIV-1 A/C variants circulating in populations of intravenous narcomaniacs in the focus in Gomel region in 1996 and in Southern and South-Eastern Ukraine in 1995-1996 are similar. This confirms a previous conclusion about the prevalence of A/C serotype among intravenous narcomaniacs in the former USSR.  相似文献   
89.
QsopA and SopA, proteins essential for stable maintenance of low copy number plasmids and encoded on plasmid QpH1 of Coxiella burnetii and the F plasmid of Escherichia coli, respectively, are shown to be membrane associated using three independent approaches: isolation of hybrid protein A-PhoA proteins that display PhoA (bacterial alkaline phosphatase) activity indicating a periplasmic location, biochemical fractionation by flotation gradient centrifugation, and subcellular localization by immunoelectron microscopy. These data provide insight into the mechanism by which partitioning protein A spatially directs plasmids into daughter cells at bacterial division.  相似文献   
90.
Upper limb ataxia is one of the most disabling symptoms of patients with multiple sclerosis (MS). There are some clinically tested therapeutic strategies, especially with regard to cerebellar tremor. But most of the methods used for treatment of limb ataxia in physiotherapy and occupational therapy are not systematically evaluated, e.g. the effect of local ice applications, as reported by MS patients and therapists, respectively. We investigated 21 MS patients before and in several steps 1 up to 45 min after cooling the most affected forearm. We used a series of 6 tests, including parts of neurological status and activities of daily living as well. At each step skin temperature and nerve conduction velocity were recorded. All tests were documented by video for later offline analysis. Standardized evaluation was done by the investigators and separately by an independent second team, both of them using numeric scales for quality of performance. After local cooling all patients showed a positive effect, especially a reduction of intentional tremor. In most cases this effect lasted 45 min, in some patients even longer. We presume that a decrease in the proprioceptive afferent inflow-induced by cooling-may be the probable cause of this reduction of cerebellar tremor. Patients can use ice applications as a method of treating themselves when a short-time reduction of intention tremor is required, e.g. for typing, signing or self-catheterization.  相似文献   
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