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Biomedical subjects

G Rose

Publications and source records attributed to G Rose.

At least 73 records · Page 4Linked to original sources
PubMed1994

Diastolic pressure as an index of salt sensitivity.

This paper analyses the association between blood pressure and sodium excretion in 3975 individuals aged 20-74 years, selected in a probability sample survey of private households carried out in Rio Grande do Sul, Brazil. Sodium and creatinine titrations were performed in casual urine samples collected at the time of BP measurements. A subsample of 611 subjects provided 24 h urine collections. The regression slopes of systolic pressure on sodium excretion increased when diastolic level was higher. At the lowest levels of diastolic pressure the slope did not differ significantly from zero. The adjusted correlation coefficient then rose progressively to a maximum of +0.41 at diastolic pressures of 95-99 mmHg. Strikingly, at diastolic pressures of > or = 100 mmHg, there was no longer any significant association between systolic pressure and sodium excretion. These results could explain some earlier contradictory findings concerning the role of salt intake in hypertension and provide estimates of expected reduction on the prevalence of hypertension in each diastolic pressure group following a reduction on salt intake of a population.

Adult↗
PubMed1994

Renovascular resistance in primary hypertension: experimental variations detected by means of Doppler ultrasound.

OBJECTIVE: To gauge the influence of renovascular resistance changes on blood flow velocity pulsatility in kidneys of hypertensive patients by means of the ultrasonic colour and pulsed-wave Doppler method, since we have previously shown in normotensive subjects that the blood flow velocity pulsatility in renal interlobar arteries varies with changes in renovascular resistance. METHODS: In six male patients with primary hypertension, renal blood flow velocity profiles were investigated by means of duplex ultrasound. Single-kidney renovascular resistance was assessed by measurements of split renal function (gamma-camera renography), renal plasma flow (steady-state para-aminohippurate clearance) and cuff blood pressure. The pulsatility index of the blood flow velocity spectrum in the renal interlobar artery and renovascular resistance were measured either at rest, during infusion of angiotensin II, or after angiotensin converting enzyme inhibition. RESULTS: A significant correlation existed between pulsatility index and renovascular resistance (r = 0.50, P < 0.002), which did not improve after correction for the blood pressure pulsatility. Changes of pulsatility index were more closely related (r = 0.64, P < 0.001) to the corresponding changes in renovascular resistance. CONCLUSIONS: With the two-dimensional image-guided colour and pulsed-wave Doppler method it is possible to assess semiquantitatively small intra-individual changes in renovascular resistance in hypertensive patients by means of pulsatility index measurements. Pharmacologically induced alterations in renovascular haemodynamics may therefore be evaluated with this technique.

Angiotensin II↗
PubMed1993

Normality, deviance and minor psychiatric morbidity in the community. A population-based approach to General Health Questionnaire data in the Health and Lifestyle Survey.

This paper investigates factors affecting the distribution of psychiatric morbidity in the community. It identifies a close relationship between mean Chronic General Health Questionnaire (CGHQ) scores in subdivisions of a large random sample of the community (the Health and Lifestyle Survey, N = 6317) and the prevalence in these groups of abnormal, above-threshold CGHQ scores. The frequency distributions of CGHQ scores in these different populations move up and down as a whole: like other physiological and behavioural attributes, these mental health outcomes in individuals are associated with characteristics of the populations in which they arise. Populations thus carry a collective responsibility for their own mental health and well-being. This implies that explanations for the differing prevalence rates of psychiatric morbidity must be sought in the characteristics of their parent populations; and control measures are unlikely to succeed if they do not involve population-wide changes.

Adolescent↗
PubMed1993

Silent cerebral embolism caused by neurologically symptomatic high-grade carotid stenosis. Event rates before and after carotid endarterectomy.

Fourteen symptomatic patients with severe extracranial internal carotid artery stenosis (> or = 70% of luminal narrowing) were monitored using long-term transcranial Doppler ultrasonography to determine the rate of clinically silent embolism of the ipsilateral middle cerebral artery. Before carotid endarterectomy (all patients being treated with intravenous heparin), 462 such events occurred during a total monitoring time of 45 h. Statistical analyses of the inter-event intervals and of the relationship between events and cardiac cycle revealed random occurrence. While the ipsilateral events were found in each subject, silent embolism of the contralateral middle cerebral artery occurred in only four patients each of whom had angiographically proven intracranial cross-flow from the symptomatic carotid territory (39 embolic events during 7 h monitoring time). The other 10 patients showed no contralateral embolism (10 h monitoring time). Five or more days (median 10 days) after surgery and cessation of intravenous anticoagulation the ipsilateral event rate had dropped to 13 in 33 h (P < 0.001) and the contralateral rate to zero. This suggests that the stenosed arterial segment is the main source of cerebral embolism detectable with ultrasound in symptomatic patients with high-grade internal carotid stenosis, and that carotid endarterectomy substantially reduces the rate of these events. Since reduction of ipsilateral stroke risk by successful endarterectomy is known to be of a similar degree in patients as those studied here, transcranially detected embolism may represent a new marker of disease activity of extracranial carotid artery stenosis.

Adult↗
PubMed1993

Effects of neurotensin and neuropeptide Y on coronary circulation and myocardial function in dogs.

This study analyzed the effects of the neuropeptides, neurotensin, and human and porcine analogue, neuropeptide Y, in anesthetized open-chest dogs. The left anterior descending coronary artery was cannulated and perfused at constant pressure via a blood reservoir. Flow to the coronary cannula was measured by an electromagnetic flowmeter, and regional segment lengths were measured by sonomicrometer crystals. Neurotensin injected into the coronary cannula resulted in a dose-dependent increase of coronary flow; neuropeptide Y resulted in a decrease of coronary flow. Because these changes in flow were not explained by systemic hemodynamic effects or alterations in regional myocardial function, they were considered to be coronary dilatation or constriction. Coronary dilatation by neurotensin was not prevented by alpha- or beta-adrenoceptor blockade but was completely abolished by indomethacin or by lowering coronary perfusion pressure to 35 mmHg when depressed systolic segment shortening indicated myocardial ischemia. Coronary constriction by neuropeptides Y persisted at coronary perfusion pressure of 35 mmHg and was only attenuated by indomethacin. We conclude that in contrast to systemic effects, coronary vasodilatation by neurotensin is mediated by a prostanoid product of cyclooxygenase. Preactivation of the prostaglandin system may explain why neurotensin lost its coronary dilator effect during myocardial ischemia. Neuropeptide Y may elicit coronary constriction in addition to mechanic reduction of coronary flow resembling severe coronary stenosis.

Animals↗
PubMed1993

RFLPs of the APOB gene: comparative study between Greeks and southern Italian peoples.

Restriction fragment length polymorphisms (RFLPs) at codons 2488 (XbaI), 3611 (MspI), and 4154 (EcoRI) of the apolipoprotein B gene were investigated in sample groups from Athens (Greece) and Calabria (southern Italy) to verify whether the distribution of the APOB gene variants in Calabria, where Greek colonization occurred in the eighth century B.C., reflects that of the present Greek population. A sample from Apulia, a southern Italian region having a history different from that of Calabria, was also analyzed. Three specific DNA regions, each containing the polymorphic site, were amplified by polymerase chain reaction on 243 samples, and the restriction data for the three groups were compared. The allelic frequencies of the samples from Apulia and Greece showed variability patterns that agree with those found in Caucasians, whereas the Calabrian sample shows remarkable peculiarities, mainly for the EcoRI RFLP. Linkage disequilibrium analyses of pairs of markers showed strong D linkage values between X-M markers, whereas the D linkage values between M-R markers were too small to be reliably estimated. Last, for both Apulians and Greeks, X-R markers showed linkage disequilibrium, whereas for Calabrians they did not. Estimates of XMR haplotypic frequencies were computed; they were found to be appreciably different between Calabrian and Greek samples, whereas the frequencies in the Apulian sample were approximately midway between those in Calabrians and Greeks.

Apolipoproteins B↗
PubMed1992

Incidence of cancers of the larynx and lung near incinerators of waste solvents and oils in Great Britain.

The Small Area Health Statistics Unit (SAHSU) is a new independent facility for the investigation of disease near industrial installations in the UK. SAHSU analysed the incidence of cancers of the larynx and lung near the incinerator of waste solvents and oils at Charnock Richard, Coppull, Lancashire (which operated between 1972 and 1980) and nine other similar incinerators in Great Britain, after reports of a cluster of cases of cancer of the larynx near the Charnock Richard site. Postcoded cancer registration data were available for 1974-84 in England and Wales and 1975-87 in Scotland. Lag periods of 5 and 10 years were used between start-up (or first registration) of the incinerators and cancer incidence. Standardised observed/expected (O/E) ratios were assessed within 3 km and 3-10 km of each site and then aggregated over all sites. Expected values were based on national rates (regionally adjusted) with and without stratification by Carstairs' index, a measure of the socioeconomic profile of areas that uses census data for enumeration districts. Data were also assessed over a range of circles up to 10 km to test for trend in O/E ratios with distance. For Charnock Richard, none of the O/E ratios within 3 km or from 3-10 km differed significantly from unity, for either cancer or lag period. In the analysis of all sites with stratification by Carstairs' index, none of these O/E ratios differed significantly from unity for the two cancers. There was no evidence of decreasing risk with distance from the sites of either cancer. We conclude that the apparent cluster of cases of cancer of the larynx reported near Charnock Richard was unlikely to be due to its former incinerator.

Cluster Analysis↗
PubMed1992

Plasma cholesterol concentration and mortality. The Whitehall Study.

UNLABELLED: OBJECTIVE--To examine the relationship between plasma cholesterol concentration and mortality from major causes of death. DESIGN: --Cohort study. SETTING--Civil service offices in London, England. PARTICIPANTS--There were 17,718 male civil servants aged 40 through 64 years at the time of study entry between 1967 and 1969. MAIN OUTCOME MEASURE--Mortality from major cause groups. RESULTS--There were 4022 deaths in the cohort over the 18 years of follow-up. Total mortality increased with cholesterol level, although mortality in the small group with very low cholesterol levels (5% of study population) was nonsignificantly higher (P greater than .5) than that of the remainder of the lowest quintile cholesterol group. Coronary heart disease mortality increased with increasing cholesterol concentration from the lowest levels (P less than .001 for trend). The cancer mortality rate in the group below the fifth centile of the cholesterol distribution was higher than in the remainder of the cohort for lung (P less than .001), pancreas (P = .05), liver (P = .09), and all smoking-related cancers (P = .02). Only for lung cancer was there a consistent inverse trend with cholesterol level (P less than .01). Rates of mortality due to non-neoplastic respiratory disease were inversely related to cholesterol level (P less than .001). Health state at the time of examination and socioeconomic position were related to cholesterol concentration--subjects in lower employment grades, with disease at baseline, with a history of recent unexplained weight loss, or who had been widowed had lower initial cholesterol levels. These associations largely accounted for the relationships between cholesterol level and noncardiovascular mortality. CONCLUSIONS--The inverse associations between plasma cholesterol concentration and mortality from certain causes of death seen in cohort studies could be because the participants with low cholesterol levels possess other characteristics that place them at an elevated risk of death.

Adult↗
PubMed1992

An improved graphical method for pattern recognition from spike trains of spontaneously active neurons.

Spontaneous activity and rhythmical oscillations are common features of large neuronal networks in mammals. Detection of repetitive spike patterns or pacemaker activity during electrophysiological recording of spontaneous action potentials from single neurons can be difficult if a "noisy" background is present. This paper describes an improved method for an online spike train analysis based on joint interval histograms (JIH, Rodiek et al. 1962). By means of higher ordered JIH the discrimination of spike patterns with repetitive bursting activity or oscillations is possible even when randomly distributed action potentials appear. Examples of simulated spike trains and those recorded from cultured hippocampal neurons are presented.

Animals↗
PubMed1992

Benzyl benzoate moist powder: investigation of acaricidal [correction of acarical] activity in cultures and reduction of dust mite allergens in carpets.

Despite advances in the understanding of dust mites, it remains difficult to control exposure to mite allergens, and it is particularly difficult to reduce mites in fitted carpets or sofas. Several chemicals have been demonstrated to kill mites or denature mite allergens, and some of these chemicals have been investigated in carpets. Benzyl benzoate (BB), which has been widely used to kill scabies mites and is known to kill mites of the genus Dermatophagoides, has been used as a method of treating carpets. The present article describes experiments in the laboratory and in houses in testing two preparations of BB, a moist powder and a foam. The moist powder is composed of two ingredients, a wetted "inert" cellulose, which is designed to act as a cleaning agent, and the active BB adsorbed onto silicates. The active powder kills 90% of mites in culture within 12 hours and 100% in 24 hours, whereas the cellulose is not acaricidal. The moist-powder preparation was highly effective at killing D. farinae and D. pteronyssinus mites in the laboratory. In carpets the moist powder, applied for 12 hours with repeated brushing, was demonstrated to reduce the concentrations of group I and group II dust mite allergens in dust recovered at 1 month. This decrease in concentration could, in part, be explained by a persistent increased recovery of dust caused by residual white powder. However, when the recovery of group II allergens was calculated as the total allergen recovered, the decrease was highly significant at 2 weeks and 4 weeks after treatment (p less than 0.001). Application of the powder to carpets for 4 hours or of the foam to sofas was less effective. After 2 months the effect on mite antigen in carpets was still present, but some increase was apparent, suggesting that repeat application after 2 or 3 months would be necessary to control mite-allergen levels.

Allergens↗
PubMed1992

Randomised controlled trial of anti-smoking advice: final (20 year) results.

STUDY OBJECTIVE: The aim was to measure experimentally the effects in middle aged men of stopping smoking. DESIGN: The study was a randomised controlled trial. SETTING AND SUBJECTS: The subjects were 1445 male smokers, initially aged 40-59 years, who were selected from the Whitehall study survey of 16,016 civil servants on the basis of a high risk of cardiorespiratory disease. MAIN RESULTS: During the next 20 years there were 620 deaths (231 from coronary heart disease), 96 cases of lung cancer, and 159 other cancers. Comparing the intervention with the normal care group, total mortality was 7% lower, fatal coronary heart disease was 13% lower, and lung cancer (deaths+registrations) was 11% lower. An excess rate for other cancers, reported previously, did not persist into the second decade of the trial. CONCLUSIONS: The results are consistent with observational studies, implying that smoking cessation by middle aged men substantially improves their changes of avoiding lung cancer or a fatal heart attack. Our estimate from the trial is that out of every 100 men who stopped smoking, between six and 10 were in consequence alive 20 years later.

Adult↗