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Biomedical subjects

T Linton

Publications and source records attributed to T Linton.

6 recordsLinked to original sources

Community-living nonagenarians in northern ireland have lower plasma homocysteine but similar methylenetetrahydrofolate reductase thermolabile genotype prevalence compared to 70-89-year-old subjects.

This cross-sectional study assessed relationships between plasma homocysteine, 'thermolabile' methylenetetrahydrofolatereductase (MTHFR) genotype, B vitamin status and measures of renal function in elderly (70-89 years) and nonagenarian (90+ years) subjects, with the hypothesis that octo/nonagenarian subjects who remain healthy into old age as defined by 'Senieur' status might show reduced genetic or environmental risk factors usually associated with hyperhomocysteinaemia. Plasma homocysteine was 9.1 micromol/l (geometric mean [GM]) for all elderly subjects. Intriguingly, homocysteine was significantly lower in 90+ (GM; 8.2 micromol/l) compared to 70-89-year-old subjects (GM; 9.8 micromol/l) despite significantly lower glomerular filtration rate (GFR) and serum B12 in nonagenarian subjects and comparable MTHFR thermolabile (TT) genotype frequency, folate and B6 status to 70-89-year-olds. For all elderly subjects, the odds ratio and 95% confidence intervals for plasma homocysteine being in the highest versus lowest quartile was 4.27 (2.04-8.92) for age <90 compared >90 years, 3.4 (1.5-7.8) for serum folate <10.7 compared >10.7nmol/l, 3.0 (0.9-10.2) for creatinine >140 compared <140 umol/l and 2.1 (1.0-4.4) for male sex. This study shows that plasma homocysteine does not invariably increase with age. Compared to similarly enlisted 70-89-year-olds, apparently well, mentally alert, community-living 90+ year olds approximating 'Senieur' status, show lower homocysteine, which is unexplained by renal function, TT genotype and B vitamin status, suggesting that lower homocysteine may be associated with survival.

Age Distribution↗

Measurement of markers of tobacco smoking in patients with coronary heart disease.

591 patients with a history of coronary heart disease had one or more biochemical markers of tobacco smoking measured. 26% were self reported smokers and a further 4% were apparent 'smoking deceivers'. The urinary nicotine metabolite concentration is an excellent marker for tobacco smoking; breath CO would be a suitable alternative for busy clinics. Half the patients were subjected to regular advice on risk factor management but there was no evidence that this contributed effectively to smoking cessation. Overall smoking cessation rate was poor.

Adult↗

[Characterization of the influenza epidemic that occurred in 1988 in the Cristobál Labra health area].

A study was carried out on the influenza epidemic which broke out in the 21 804-inhabitant health area of the Cristóbal Larra Polyclinic of City of Havana Province on February 29, 1988. It was found that medical consultations for acute respiratory tract infections totalled 2046 during the 30-day epidemic; 1860 of these (90.9%) were first consultations, representing about 9% of the area population. The epidemic peak was reached 22 days after the outbreak. Higher consultation rates were of patients under 5 years, and the highest consultation coefficients were registered on Mondays. The application of the Rvachov-Baroyan model for local epidemic prognosis was not effective in the health area under study.

Adolescent↗

A comparison of the haemodynamic and hormonal effects of low and conventional dose cyclopenthiazide in normal volunteers.

In this study we compared low (125 micrograms) and conventional (500 micrograms) doses of cyclopenthiazide on the renin angiotensin system, plasma and extracellular fluid volumes and the pressor responsiveness to angiotensin II since we have previously shown that the two doses have the same antihypertensive effect but different effects on plasma renin activity. Following a two week placebo run-in period, 8 healthy male volunteers received 125 micrograms or 500 micrograms of cyclopenthiazide for 2 treatment periods of 4 weeks as part of a double blind, 2-part crossover study with treatment periods separated by a 4-week placebo washout phase. Measurements were made on two study days at the beginning and end of the active treatment periods. On the first day serum potassium, plasma renin activity and plasma angiotensin II levels were measured after a 1 h period of supine rest. Plasma and extracellular fluid volumes were also measured after appropriate equilibration times. The blood pressure responses to angiotensin II were assessed on day 2. The 500 micrograms dose of cyclopenthiazide had a greater effect than the 125 micrograms dose on plasma renin activity, serum potassium, angiotensin II levels and extracellular fluid volumes. Neither drug had any effect on plasma volume or the responsiveness to infused angiotensin II. Low dose cyclopenthiazide failed to increase angiotensin II levels, contract body fluid volumes or attenuate vascular reactivity in normotensive volunteers.

Adult↗

[Primary-care morbidity and true morbidity due to acute respiratory infections].

The present work presents the study of morbidity due to acute respiratory infections (ARI) in areas of the town of Lisa in Ciudad Habana, and Isla Juventud (Cuba), to characterize different aspects of morbidity measured by health care attendance and to measure true morbidity. About 90% of consultations for ARI were first-time consultations, while their ratio to further consultations was 5.3. True morbidity rates (TMR), obtained trough active research, ranged from 110.4 to 163.4 cases per 1000 inhabitants, considerably higher than morbidity rates measured by primary care consultations (MRPCC) in the same time period. The true morbidity index (TMI), as measured by the ratio of the two previous rates, ranged from 5 to 15. A high proportion (47.6%) of cases reported no medical care attendance. These results provide approximate estimates of true morbidity in the study area, and allow the establishment of a new control program, also improving epidemiologic surveillance within primary care activities.

Acute Disease↗