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Biomedical subjects

G Rose

Publications and source records attributed to G Rose.

At least 199 records · Page 11Linked to original sources

A temperature controller for in vitro recording chambers.

An inexpensive, electrically quiet temperature controller designed to provide biological temperatures in chambers used to maintain tissue slices for in vitro recording is described. The circuit incorporates several advantageous features: (1) an integrated circuit temperature sensor is used which produces a linear output and is immune to self-heating error; (2) a single +12-18 V, 1 A DC supply will power the unit; (3) the output regulator cannot be damaged by overheating or short-circuiting; and (4) the temperature of the preparation is displayed.

Animals↗

Weight and mortality in the Whitehall Study.

Ten-year mortality rates in men aged 40-64 years in the Whitehall Study were analysed in relation to weight and height at the initial examination. At ages 40-49 "all-causes" mortality increased with increasing body mass index; but this simple relation disappeared at older ages, where there was an increased mortality in the lowest quintile of body mass index. The "all-ages" relation was "J"-shaped, and this could not be explained by the confounding effects of blood pressure, cholesterol values, and cigarette smoking. Some, but not all, of the J shape was due to a high short-term mortality in thin men from cancers (presumably already present at examination). At younger ages mortality from coronary heart disease was positively related to body mass index, but this depended on its association with other risk factors. Mortality from causes other than cancers or coronary heart disease was highest in the lowest quintile of body mass index.

Adult↗

Incubation period of coronary heart disease.

Serum cholesterol concentrations and blood pressure were measured during 1958-64 among men aged 40-59 who took part in the Seven Countries Study. In the present study these measurements were related to the national mortality from coronary heart disease in the periods 1959-61, 1964-6, 1969-71, and 1974-6. The correlations increased with time (r = +0.86, 0.90, 0.93, and 0.96 respectively for serum cholesterol concentration and r = +0.48, 0.56, 0.57, and 0.64 for systolic blood pressure), suggesting that the "incubation period" between exposure to major coronary risk factors and the maximum effects on mortality may be 10 years or more.

Adult↗

Population study of blood pressure and associated factors in St Lucia, West Indies.

A population survey of blood pressure in St Lucia, West Indies has confirmed that high blood pressure constitutes an important public health problem. In common with other studies blood pressure was found to be significantly correlated with body weight, possibly by a primary effect on diastolic pressure. Blood pressure was also significantly correlated with casual urinary sodium/potassium and potassium/creatinine ratios in those under 45 years of age. This unexpected finding suggests that casual urinary electrolyte estimations may in some circumstances be a useful guide to intake, perhaps especially in populations with more stable intakes. An independent role of potassium in the aetiology of high blood pressure would have important public health implications.

Adolescent↗

Bias.

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Clinical Trials as Topic↗

Long-term potentiation of excitatory synaptic transmission in the rat hippocampus: the role of inhibitory processes.

1. The possibility that changes in inhibitory processes are responsible for long-term potentiation (l.t.p.) was examined using the rat hippocampal slice preparation.2. Inhibitory pathways were characterized using both extra- and intracellular recordings from the CA1 pyramidal cell layer. Stimulating electrodes were placed in either stratum radiatum or the alveus to allow orthodromic or antidromic activation of the pyramidal cells.3. Using extracellular recordings, inhibition was studied by applying paired pulses at interstimulus intervals of 20-500 msec through either the same or different stimulating electrodes, and quantifying the reduction in the population spike. An antidromic conditioning pulse was least effective in influencing the test response, while paired stimuli delivered through separate stimulators in stratum radiatum revealed the longest duration effects. Inhibition was either reduced or enhanced, depending upon the stimulation paradigm, with increasing stimulus intensity.4. With l.t.p., alterations in paired-pulse inhibition were observed corresponding to the changes in conditioning pulse amplitude. Reducing stimulus intensity to restore the initial conditioning pulse amplitude eliminated these effects.5. Using intracellular recordings, the effects of l.t.p. on inhibition were studied by examining changes in e.p.s.p.-i.p.s.p. sequences, i.p.s.p.s evoked by antidromic stimulation, and spontaneous depolarizing i.p.s.p.s observed with KCl-filled electrodes.6. Following l.t.p. enhanced e.p.s.p.s and slightly reduced, but prolonged, i.p.s.p.s were observed in response to orthodromic stimulation. Antidromically evoked, as well as spontaneous, i.p.s.p.s were unaffected.7 It is concluded that alterations in inhibitory processes are not responsible for l.t.p. in hippocampal subfield CA1. However, changes in the strength of inhibitory synapses as a consequence of long-term potentiation may modify the functional character of the hippocampal connexions.

Action Potentials↗

A randomised controlled trial of anti-smoking advice: 10-year results.

Ten-year results are reported from a randomised controlled trial of anti-smoking advice in 1445 male smokers, aged 40-59, at high risk of cardiorespiratory disease. After one year reported cigarette consumption in the intervention group (714 men) was one-quarter that of the "normal care" group (731 men); over 10 years the net reported reduction averaged 53%. The intervention group experienced less nasal obstruction, cough, dyspnoea, and loss of ventilatory function. Over 10 years their mortality from coronary heart disease was 18% lower than controls (49 and 62 deaths), and that for lung cancer was 23% lower (18 and 24 deaths). Deaths from non-lung cancers were higher in the intervention group (28 v 12 deaths). This unexpected difference was due about equally to an excess in intervention and a deficiency in normal care men, it showed no site specificity, and it was unrelated to change in smoking habit. These findings suggest that it is more likely to have been due to change than to intervention. The total number of deaths were 123 in the intervention group and 128 in normal care (95% confidence limits of difference -22% to +23%). The policy of encouraging smokers to give up the habit should not be changed.

Adult↗

Cigarettes, lung cancer, and coronary heart disease: the effects of inhalation and tar yield.

Ten-year mortality rates for lung cancer and coronary heart disease have been related to cigarette smoking habits in 17 475 male civil servants aged 40-64 and in sample of 8089 male British residents aged 35-69. Both diseases were more frequent in smokers. Lung cancer rates were higher overall for "non-inhalers", particularly in heavy smokers. Tar yield correlated with the risk of lung cancer in non-inhalers but less so in inhalers. Conversely, coronary deaths were more common among inhalers, and the effect of tar/nicotine yield (such as it was) was confined to inhalers. It appears that there are subtle interactions between the amount smoked, the tar/nicotine yield of the cigarette, and the style of smoking. Thus the effects of a change in cigarette characteristics are hard to predict, and they may be different for respiratory and cardiovascular disease.

Adult↗

Alcohol and mortality: a U-shaped curve.

In a longitudinal study of civil servants, 1422 men were classified according to their average daily alcohol intake. Over 10 years of follow-up, the mortality rate was lower in men reporting moderate alcohol intake than in either non-drinkers or heavier drinkers (greater than 34 g alcohol per day). Cardiovascular mortality was greater in non-drinkers and non-cardiovascular mortality was greater in the heavier drinkers. The heavier drinkers had higher mean blood pressures and contained a greater proportion of smokers. A multivariate analysis showed this U-shaped relationship between reported alcohol consumption and subsequent mortality to be largely independent of differences in smoking, blood pressure, plasma cholesterol, and grade of employment.

Adult↗