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Biomedical subjects

R Wang

Publications and source records attributed to R Wang.

At least 703 records · Page 39Linked to original sources
PubMed1987

Alcohol and dilated cardiomyopathy: incidence and correlation with clinical outcome.

Among a group of 28 elderly veterans with dilated cardiomyopathy regularly attending an outpatient heart failure clinic, half had a history of habitual heavy drinking. It was concluded that chronic heavy drinking was the only identifiable factor responsible for the heart failure in three of these patients. Eleven other patients also had chronic heavy drinking as a possible etiological factor of their heart failure in addition to Coronary Artery Disease and/or hypertension. Less than 50% of the heavy drinkers totally abstained from alcohol after seeking medical treatment although they reduced their drinking significantly. All three patients with clear alcoholic cardiomyopathy discontinued drinking and showed marked improvement in cardiac status. The discontinuation of drinking did not appear to be associated with improvement in the remaining heavy drinkers and those patients who reported a history of moderate drinking.

Aged↗
PubMed1987

Structural alterations that differentially affect the mutagenic and antitrichomonal activities of 5-nitroimidazoles.

Two approaches have been used to develop nonmutagenic 5-nitroimidazoles. Both approaches are based on knowledge of the likely mechanisms by which this class of compounds cause mutagenicity. The first approach involved incorporating readily oxidizable gallate derivatives into the molecule. In one case, a very weakly mutagenic active antitrichomonal agent was obtained. The second approach involved incorporating a substituent at the C4 position of the ring. This generally resulted in a large reduction in mutagenicity and a lowering of antitrichomonal activity in vitro. In certain cases, however, mutagenicity was dramatically reduced while moderate antitrichomonal activity was retained. For example, 1,2-dimethyl-4-(2-hydroxyethyl)-5-nitroimidazole (5) showed good antitrichomonal activity in vitro (ED50 = 2 micrograms/kg) while possessing only 4% of the mutagenicity of metronidazole.

Animals↗
PubMed1987

The risks and benefits of clozapine versus chlorpromazine.

Clozapine is an atypical antipsychotic drug with reduced risk of unwanted neurological effects in comparison with other drugs. In this multicenter study, 151 hospitalized schizophrenic patients were randomly assigned to treatment under double-blind conditions to assess the antipsychotic efficacy and safety of clozapine versus chlorpromazine. All patients exhibited tardive dyskinesia or other extrapyramidal side effects associated with at least two prior neuroleptics. Eleven patients were dropped from treatment due to extrapyramidal symptoms while being treated with chlorpromazine; only one clozapine patient's treatment was terminated for this reason. Clozapine patients exhibited clinical improvement superior to that of chlorpromazine patients as assessed by the Brief Psychiatric Rating and Clinical Global Impression scales. These results suggest that clozapine is well tolerated and may be therapeutically superior to chlorpromazine in treating psychotic behavior. Agranulocytosis potential can be minimized by frequent white blood cell counts and removing nonresponding patients from treatment prior to the peak risk period (months 2 through 6).

Adult↗
PubMed1986

Studies on the mechanism of activation and the mutagenicity of ronidazole, a 5-nitroimidazole.

Substantial evidence implicates the obligatory nucleophilic attack by water at C4 for the elimination of the carbamate and subsequent immobilization by electrophilic attack on protein thiols. Consequently, the strong correlation between the structural requirements for protein alkylation and for mutagenicity in TA100 suggests a possible role of nucleophilic addition at C4 or at the 2-methylene carbon for the expression of mutagenicity. Further studies directed at evaluating this possibility are currently in progress.

Alkylation↗
PubMed1986

Multiple Ya subunits of glutathione S-transferase detected by monoclonal antibodies.

Monoclonal antibodies to ligandin (YaYa) and glutathione (GSH) S-transferase B (YaYc) were produced by hybridomas derived from the fusion of mouse myeloma cells and spleen cells of mice immunized with the YaYa or YaYc proteins, respectively. Enzyme-linked immunosorbent assay was used to screen for antibody-producing clones. Immunoblotting of the subunits of transferase B, ligandin, and another GSH S-transferase containing Yb subunits showed that the monoclonal antibodies produced by two anti-YaYa subclones recognized the Ya subunits of both ligandin and transferase B, but they did not bind Yc or Yb subunits. It was also revealed that antibodies produced by several anti-YaYc subclones recognized the Yc subunit, but not the Ya subunit of the antigen which was used for the immunization of the mice. However, these monoclonal antibodies did bind the Ya subunit of ligandin. These results indicate that the Ya subunits of GSH S-transferase B and of ligandin do share at least one common determinant. However, these two Ya subunits are structurally distinct as evidenced by their differences in binding by monoclonal anti-YaYc antibodies.

Animals↗
PubMed1986

An unusual case of postoperative pseudoaneurysm of the left ventricle: Doppler echocardiographic findings.

Two years and 9 months after aneurysmectomy of a true left ventricular aneurysm, a 55 year old man presented with clinical features suggestive of acute pericarditis. The echocardiogram revealed a large echo-free space outside the heart. Doppler study showed phasic flow between the echo-free space and the left ventricular cavity through a distinct interruption of the left ventricular apical wall endocardial echoes. The diagnosis of pseudoaneurysm was made and was subsequently confirmed by angiographic and operative findings. After successful repair, a repeat Doppler echocardiographic examination showed a marked reduction in the echo-free space, absence of communication with the left ventricle and no flow signal in the space.

Coronary Angiography↗
PubMed1986

Occupational exposure to chlorophenates. Renal, hepatic and other health effects.

A group of 71 chlorophenate-exposed sawmill workers were identified as part of a group undergoing an extensive health and environmental evaluation in a pulp mill. This group was compared with a group (N = 351) with no physical proximity to the area in which chlorophenates were used. Exposure was higher for those directly handling the wood and lower for those working in the area but not handling the wood. Those with chlorophenate exposure were not significantly more likely to report a history of jaundice or liver, kidney or heart disease. Moreover, the serum creatinine, bilirubin, glutamic oxaloacetic transaminase (GOT), and alkaline phosphatase values did not differ from those of the reference group. The hemoglobin level was similar in the three groups. But the peripheral blood leukocyte count was marginally lower in the exposed groups and their hematocrit was reduced, significantly so for the heavily exposed group. Urinalysis showed an increased prevalence of microscopic hematuria, especially with lower cell counts. No unequivocal explanation is available for the reduced hematocrit or the low level of hematuria.

Adult↗
PubMed1985

Immunoglobulin JH, C mu, and C gamma gene rearrangements in human B lymphocytes clonally transformed by Epstein-Barr virus.

Somatic rearrangements and deletions of immunoglobulin gene segments have been demonstrated in several types of murine B cells. In addition, rearrangements of the JH, C mu, and light chain immunoglobulin gene segments have been reported in human pre-B-cell leukemias and B-cell lymphomas. We have used recombinant DNA probes for the human JH, C mu, and C gamma immunoglobulin gene loci to analyze the genetic events associated with heavy chain gene expression in human B cells clonally transformed by Epstein-Barr virus. Southern hybridization analysis of BamHI-digested cell clone DNAs shows that these human B-cell clones often have bi-allelic JH rearrangements and that heavy chain isotype switching is associated with bichromosomal C mu and C gamma gene rearrangements. Deletions of germ line C mu and C gamma segments were observed that were sometimes bi-allelic. Overall, the observed rearrangements and deletions of heavy chain constant region genes suggest that human heavy chain class switching proceeds in a general order consistent with the proposed order of the heavy chain gene classes along chromosome 14.

B-Lymphocytes↗
PubMed1985

Risks of lung cancer, chronic bronchitis, ischaemic heart disease, and stroke in relation to type of cigarette smoked.

In a case control study of over 12 000 inpatients aged 35-74, risk of lung cancer, chronic bronchitis, and, particularly in those aged 35-54, ischaemic heart disease was positively associated with the number of manufactured cigarettes smoked daily and was negatively associated with long term giving up. Risk of stroke was not clearly related to smoking. Among manufactured cigarette smokers, lung cancer risk tended to be lowest in those who had always smoked filter cigarettes. This pattern was, however, evident only in men who additionally smoked pipes, cigars or handrolled cigarettes and in women, not being seen in men who smoked only manufactured cigarettes. Risk of lung cancer was not clearly related to time of switch to filter cigarettes. A markedly lower risk of chronic bronchitis was seen in men, but not women, who smoked filter rather than plain cigarettes. Heart disease risk did not vary by type of cigarette smoked 10 years before admission, but, compared with those who had never smoked filter cigarettes, those who had ever smoked filter cigarettes had a higher risk in men and a lower risk in younger women. Compared with the general population, markedly more controls were ex-smokers, suggesting incipient disease, whether or not smoking related, may alter smoking habits, thus affecting the interpretability of the findings. Control smokers were also relatively much more likely to report smoking plain cigarettes than expected. This comparison, not made in other studies relating risk to type of cigarette smoked, indicates that great care must be taken in verifying validity of reported smoking habits. While our findings are compatible with other evidence that risk of lung cancer and chronic bronchitis is probably reduced by switching from plain to filter cigarettes, they underline the difficulties in obtaining valid evidence from epidemiological studies.

Adult↗
PubMed1985

Warfarin versus dipyridamole-aspirin and pentoxifylline-aspirin for the prevention of prosthetic heart valve thromboembolism: a prospective randomized clinical trial.

In a prospective, randomized, parallel study, two regimens of platelet-suppressant therapy (PST)--dipyridamole-aspirin and pentoxifylline-aspirin--were compared with standard oral anticoagulation with warfarin in the prevention of prosthetic heart valve thromboembolism. In the entire group of 254 patients followed for 395.6 patient-years, the thromboembolic rate was significantly less in the warfarin group (warfarin vs dipyridamole-aspirin, p less than .005; warfarin vs pentoxifylline-aspirin, p less than .05). Subgroup analysis disclosed that, in patients with isolated mitral valve replacement, warfarin was superior to both of the PSTs with respect to the prevention of thromboembolism (warfarin vs dipyridamole-aspirin, p = .005; warfarin vs pentoxifylline-aspirin, p less than .05). Furthermore, a significant number of our patients could not tolerate the antiplatelet agents. However, in the rare situation in which repeated significant bleeding occurs despite careful adjustment of the dosage of warfarin, PST may be an acceptable alternate method of thromboembolism prophylaxis.

Adult↗