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71.
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Background and Purpose

The Kvβ1.3 subunit modifies the gating and pharmacology of Kv1.5 channels in a PKC-dependent manner, decreasing channel sensitivity to bupivacaine- and quinidine-mediated blockade. Cardiac Kv1.5 channels associate with receptor for activated C kinase 1 (RACK1), the Kvβ1.3 subunit and different PKC isoforms, resulting in the formation of a functional channelosome. The aim of the present study was to investigate the effects of PKC inhibition on bupivacaine and quinidine block of Kv1.5 + Kvβ1.3 channels.

Experimental Approach

HEK293 cells were transfected with Kv1.5 + Kvβ1.3 channels, and currents were recorded using the whole-cell configuration of the patch-clamp technique. PKC inhibition was achieved by incubating the cells with either calphostin C or bisindolylmaleimide II and the effects of bupivacaine and quinidine were analysed.

Key Results

The voltage-dependent inactivation of Kv1.5 + Kvβ1.3 channels and their pharmacological behaviour after PKC inhibition with calphostin C were similar to those displayed by Kv1.5 channels alone. Indeed, the IC50 values for bupivacaine were similar in cells whose PKC was inhibited with calphostin C or bisindolylmaleimide II. Similar results were also observed in the presence of quinidine.

Conclusions and Implications

The finding that the voltage-dependence of inactivation and the pharmacology of Kv1.5 + Kvβ1.3 channels after PKC inhibition resembled that observed in Kv1.5 channels suggests that both processes are dependent on PKC-mediated phosphorylation. These results may have clinical relevance in diseases that are characterized by alterations in kinase activity.  相似文献   
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Background  

Human immunodeficiency virus (HIV) infection is very prevalent in Brazil. HIV therapy has been recently associated with coronary heart disease (CHD). Dyslipidemia is a major risk factor for CHD that is frequently described in HIV positive patients, but very few studies have been conducted in Brazilian patients evaluating their lipid profiles.  相似文献   
76.
Recurrent ulcer after successful treatment with cimetidine or antacid   总被引:5,自引:0,他引:5  
This study was designed to compare the rates of duodenal ulcer healing and recurrence after treatment with cimetidine or antacid. Patients with endoscopically documented duodenal ulcer received cimetidine, 1200 mg daily, or Mylanta II, 7 oz daily, in a randomized, double-blind trial. For the 69 patients in each group who completed the healing phase of the trial, endoscopic ulcer healing was almost identical. At 2, 4, and 6 wk, the cumulative percent healed on antacid was 33%, 64%, and 80%, and on cimetidine it was 25%, 62%, and 86%. The 114 patients with healed ulcer were observed on no therapy and underwent additional endoscopy to detect recurrences when symptomatic or at 3, 6, and 12 mo. There was no difference in the frequency of recurrences between treatments. At 3 and 6 mo, the cumulative percentages of patients with recurrence were 29% and 56% after antacid therapy and 36% and 55% after cimetidine therapy. Some patient variables were associated with delayed ulcer healing or ulcer recurrence. These included sex, pain frequency, smoking, disease duration, and acid secretion.  相似文献   
77.
Dietary fatty acids are actively incorporated into membrane lipids, and fat intake can modify the composition and the biochemical activity of cellular membranes and the pattern of plasma lipoproteins. Industrial hydrogenation of polyunsaturated oils leads to the formation of isomeric trans fatty acids which are incorporated into cellular membranes when they are present in the diet. The trans fatty acid amount present in hydrogenated oils depends on the degree of hydrogenation, being high for partially hydrogenated oils and low for highly hydrogenated oils. Hydrogenated fish oil is widely used in some countries for the production of margarine and industrial fats. This study compares the fatty acid composition of plasma, erythrocytes, subcutaneous adipose tissue, and hepatic microsomal membranes and the plasma lipoprotein profile after feeding rats with a synthetic diet containing either fish oil, partially hydrogenated fish oil, or highly hydrogenated fish oil. It is observed that the tissue content of monounsaturated fatty acids increases and that the content of polyunsaturated fatty acids decreases after an increase of the degree of hydrogenation of the dietary fat. Tissues from animals fed partially hydrogenated fish oil show significant amounts of trans fatty acids only. The plasma triacylglyceride composition and the lipoprotein profile are also altered by the degree of hydrogenation of the dietary fat. Triacylglycerides decrease after highly hydrogenated fat feeding only. Total cholesterol and low-density lipoprotein cholesterol are significantly increased after partially hydrogenated fat feeding. Although no direct evidence is presented, this effect may be attributable to the high content of trans isomers of this dietary fat which nutritionally may behave as saturated fatty acids.  相似文献   
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The purpose of this report was to evaluate scintigraphy analysis of Southern blot hybridization as a method to quantify the breakpoint cluster region (BCR) rearrangement of Philadelphia chromosome (Ph)+ chronic myelogenous leukemia (CML). Cytogenetic and molecular studies performed simultaneously on 474 bone marrow and/or blood samples from 300 patients treated with alpha-interferon-based therapy were compared. Molecular results were expressed as the percentage of rearranged BCR bands versus the total scintigraphic signal. The percentage of Ph+ metaphases was calculated on 25 metaphases. The results of molecular studies obtained on both peripheral blood and bone marrow samples were identical. The rank correlation between the BCR quantification and the percentage of Ph positivity in 465 samples was excellent (r = .78). However, of 99 samples with a normal karyotype, 24% had a BCR rearrangement. Of 86 samples with no BCR rearrangement, 13% showed a Ph chromosome. Of 49 samples with partial cytogenetic remission (Ph+ metaphases, 1% to 34%), 23% had no BCR rearrangement. In samples with a minor or no cytogenetic response (Ph+ metaphases, > 34%), BCR analysis overestimated the degree of response in 73 of 326 samples (22%). Nevertheless, survival analysis by BCR quantification level showed statistically better outcome for patients in complete or partial molecular response (P < .01). Molecular quantification of BCR was useful in monitoring the course of Ph+ CML. This method, which can be used on peripheral blood, detected residual disease not shown by cytogenetic analysis and was prognostically relevant as a measure of disease suppression.  相似文献   
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