Biomedical subjects

J Duan

Publications and source records attributed to J Duan.

78 records · Page 5Linked to original sources

PubMed1990

Tobacco smoking, alcohol consumption, and risk of oral cancer: a case-control study in Beijing, People's Republic of China.

A case-control study of oral cancer was conducted in Beijing, People's Republic of China (PRC). The study was hospital-based and controls were hospital in-patients matched for age and gender with the cases. The response rates for cases and controls were 100 percent and 404 case/control pairs were interviewed. Tobacco smoking and alcohol consumption emerged as independent risk factors for oral cancer. For tobacco smoking, the association was considerably stronger for smokers of pipes than for smokers of cigarettes. For all kinds of tobacco, expressed as cigarette equivalents, the odds ratio (OR) for total pack-years smoked, among males, rose from 1.0 in never-smokers to 3.7 (95 percent confidence interval, 1.8-7.4) in the highest quintile of exposure. Similar results were found for females. The association with tobacco consumption was strong for squamous cell carcinoma but there was no trend in risk associated with tobacco for adenocarcinomas and other histologic types. So few women reported consuming alcohol that this variable could be examined only in males. Risk in the highest category of total lifetime intake of alcohol relative to that in lifetime abstainers was 2.3 (1.1-4.8) with a significant trend in risk with increasing dose (P less than 0.002). The combined effects of tobacco and alcohol appear to be approximately multiplicative in males. The attributable risk of oral cancer for tobacco among tobacco smokers was estimated as 34 percent (45 percent among males and 21 percent among females); for alcohol consumption in males the estimate was 23 percent.

Adenocarcinoma↗

PubMed1990

Dentition, oral hygiene, and risk of oral cancer: a case-control study in Beijing, People's Republic of China.

A case-control study of oral cancer was conducted in Beijing, People's Republic of China. The study was hospital-based and controls were hospital in-patients matched to the cases by age and gender. A total of 404 case/control pairs were interviewed. This paper provides data regarding oral conditions as risk factors for oral cancer, with every patient having an intact mouth examined (pre-operation among cases) using a standard examination completed by trained oral physicians. After adjustment for tobacco smoking and alcohol consumption, poor dentition--as reflected by missing teeth--emerged as a strong risk factor for oral cancer: the odds ratio (OR) for those who had lost 15-32 teeth compared to those who had lost none was 5.3 for men and 7.3 for women and the trend was significant (P less than 0.01) in both genders. Those who reported that they did not brush their teeth also had an elevated risk (OR = 6.9 for men, 2.5 for women). Compared to those who had no oral mucosal lesions on examination (OR = 1.0), persons with leukoplakia and lichen planus also showed an elevated risk of oral cancer among men and women. Denture wearing per se did not increase oral cancer risk (OR = 1.0 for men, 1.3 for women) although wearing metal dentures augmented risk (OR = 5.5 for men). These findings indicate that oral hygiene and several oral conditions are risk factors for oral cancer, independently of the known risks associated with smoking and drinking.

Adult↗

PubMed1990

Interactions between inhibition factors on microbial stability of fruit-based systems.

Measurement of metabolic CO2 by head space gas chromatography was used in the preparation of shelf-life maps of fruit-based systems. The systems analysed, all of which were peach-based, differed with respect to aw (0.995, 0.934 and 0.890), pH (3.02, 3.60 and 4.09) and benzoic acid concentration (0, 100 and 200 ppm). The test microorganism was a strain of Saccharomyces cerevisiae isolated from spoiled soft-drinks and chosen for its characteristic of multiple resistance. Three different thermal treatments were applied (54 degrees C for 15 min, 58 degrees C for 8 min, 63 degrees C for 3 min) to the systems and their effectiveness was evaluated in relation to the untreated controls. In contrast with observations for osmotolerant species, the relative preservative effectiveness on the test strain decreased with reducing aw and showed only a slight synergistic action with thermal treatment. Besides, the aw of the systems interacted synergistically with the thermal treatment effectiveness in a manner differing from that described for osmotolerant species.

Benzoates↗

PubMed1989

Relationship between oxidative phosphorylation and adenine nucleotide translocase activity of two populations of cardiac mitochondria and mechanical recovery of ischemic hearts following reperfusion.

The possible relationship of the atractyloside-sensitive adenine nucleotide translocase activity, oxidative phosphorylation, and the recovery of ventricular contractility following reperfusion of the ischemic isolated rat heart was studied. Five minutes of total global ischemia without reperfusion produced a significant depression in adenine nucleotide translocase in subsarcolemmal mitochondria (SLM), whereas a minimum of 10 min ischemia was required to observe a significant depression in interfibrillar mitochondria (IFM). Increasing durations of ischemia resulted in a progressively larger depression in translocase activity, with a maximum depression of approximately 75% seen in both populations following 20 min ischemia. In contrast, oxidative phosphorylation was totally unaffected in either mitochondrial population following up to 20 min of ischemia. We assessed whether translocase activity or oxidative phosphorylation were related to contractile recovery in hearts reperfused following various durations of ischemia. In SLM, translocase activity was further depressed following reperfusion compared with pre-reperfusion ischemic values, whereas with IFM only reperfusion following 5 min ischemia produced a further depression in translocase values. Oxidative phosphorylation rates of SLM and IFM were significantly depressed following reperfusion of ischemic hearts, although SLM exhibited a generally higher sensitivity in this regard. In reperfused hearts, an overall significant relationship was found between oxidative phosphorylation rate and adenine translocase activity as well as between translocase activity and post-reperfusion contractile recovery. These data show that ischemia can produce a significant depression in translocase activity in the absence of any change in oxidative phosphorylation. The results also suggest that the depression in mitochondrial ADP/ATP translocase and subsequent inhibition of oxidative phosphorylation in the reperfused heart may represent one of the important contributory mechanisms involved in cardiac failure and injury during acute ischemia and reperfusion.

Animals↗

PubMed1989

A rapid phosphate-induced depression of heart subsarcolemmal mitochondrial oxidative phosphorylation.

Inorganic phosphate (Pi) was added to suspensions of interfibrillar (IFM) and subsarcolemmal (SLM) mitochondria. With 20 mM Pi, significant depression in SLM oxidative phosphorylation was seen after 60 seconds exposure whereas 120 seconds was required to depress IFM, although to a lesser degree. Oxidative phosphorylation rate of SLM was significantly depressed by 1 minute incubation with 2.5-20 mM Pi, whereas IFM were unaffected. Five minute incubation with similar Pi concentrations produced equal depression in both populations. We postulate that the rapid increase in intracellular Pi may contribute to contractile failure associated with early ischemia by depressing a critical pool of ATP synthesis represented by SLM.

Animals↗

PubMed1987

Enhancement of clonidine-induced analgesia by lesions induced with spinal and intracerebroventricular administration of 5,7-dihydroxytryptamine.

The role of serotonin (5-HT) in analgesia induced by clonidine was examined by determining the effect of intraspinal (i.s.) and intracerebroventricular (i.c.v.) injections of 5,7-dihydroxytryptamine (5,7-DHT) on analgesia produced by clonidine in the tail-flick and hot plate tests. Depletion of amines was verified by high performance liquid chromatography analysis. Intraspinal injections of 5,7-DHT potentiated the action of clonidine in both tests for analgesia and caused depletion of 5-HT in the spinal cord. Intracerebroventricularly injected 5,7-DHT also increased the action of clonidine and depleted 5-HT in brain as well as in the spinal cord. In the groups given intracerebroventricular injections, there appeared to be a biphasic increase in the action of the clonidine. Significant hyperalgesia from pretreatment with neurotoxin was observed only on a limited number of occasions. The present results indicate that 5-HT mechanisms in the CNS are important mediators of the analgesic action of clonidine. Interactions between clonidine and 5-HT systems at both spinal and supraspinal sites are considered.

5,7-Dihydroxytryptamine↗