Search PubMed⌕ Search

Biomedical subjects

A Amery

Publications and source records attributed to A Amery.

At least 37 records · Page 2Linked to original sources
PubMed1994

Is a positive association between lead exposure and blood pressure supported by animal experiments?

The possible association between low-level lead exposure and blood pressure and the causal nature of any such relationship continue to be debated. A recent meta-analysis of the human model data showed that on average a doubling of blood lead was associated with a rise in blood pressure averaging 1 mm Hg systolic and 0.6 mm Hg diastolic. The older animal studies, however, failed to show a significant pressure increase with massive lead exposure. This review therefore attempts to determine whether the more recent animal studies are supportive of a positive association between lead exposure and blood pressure elevation. Of the 21 animal studies published since 1977, one was carried out in dogs, one in pigeons, and the remainder in various rat strains. In the articles in which all the lead doses had been higher than 1 ppm, the association between blood pressure and exposure was found to be positive in seven, inconsistent in three, absent in four, and negative in one. Of the six animal experiments that employed lead doses not exceeding 1 ppm, five reported a small pressor effect. One of these five positive low-dose studies, however, failed to show a dose-effect relationship when exposure was increased from 0.1 to 1 ppm. In conclusion, most, but not all animal studies published since 1977 found a positive association between blood pressure and lead exposure. However, publication bias may have inflated the number of positive studies appearing in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Respiratory-related blood pressure variability in patients after heart transplantation.

Our objective was to study whether the variations of blood pressure synchronous with respiration depend on the simultaneous changes of heart rate. Power spectral analysis of the heart period or R-R interval, blood pressure, and respiratory activity was performed by fast Fourier transform during 30 min of supine rest in 12 patients between 16 and 23 days after orthotopic heart transplantation and in 12 age- and sex-matched normal control subjects. The components of the variations of the R-R interval and blood pressure associated with respiration [high-frequency (HF) components] were derived from the power spectra. The HF component of the power spectrum of the R-R interval was almost absent in the transplanted patients compared with the control subjects (2.9 vs. 104 ms2; P < 0.001), whereas the HF component of the power spectrum of blood pressure was not significantly different between the two groups (1.72 vs. 1.65 mmHg2 for systolic and 0.35 vs. 0.60 mmHg2 for diastolic blood pressure). Respiratory variations of both systolic and diastolic blood pressure in humans can depend only slightly on the respiratory heart rate variations.

Blood Pressure↗
PubMed1994

Bleeding peptic ulcer: an audit of conservative management.

One hundred and twenty-six of 157 consecutive patients (80%) admitted for a bleeding peptic ulcer were treated conservatively and retrospectively analysed. There were 52% duodenal, 41% gastric and 7% combined ulcers. The initial shock index (pulse/systolic blood pressure) was in excess of one in 10%. For 22% of the patients no transfusion was required but 10% had more than 6 units of blood during their hospital stay. Forty-nine per cent were on nonsteroidal anti-inflammatory drugs and 83% had at least one coexisting systemic disease. Six patients (5%) had a further haemorrhage, four of whom died. A total of 10 patients (8%) died. Five of them were related to the peptic ulcer disease but also had terminal or multiple systemic diseases precluding any surgery. Their poor short-term prognosis shows how difficult it will be to effectively reduce the mortality in this particular group of conservatively treated patients, even with the recent advent of endoscopic haemostasis, and stresses the importance of carefully identifying high risk patients in trials mounted to improve on the current mortality figures.

Adult↗
PubMed1994

The Hypertension in the Very Elderly Trial (HYVET). Rationale, methodology and comparison with previous trials.

The Hypertension in the Very Elderly Trial (HYVET) is a multicentre, open, randomised, controlled trial. The aim of this trial is to investigate the effect of active treatment on stroke incidence in hypertensive patients over the age of 80 years. Secondary end-points include total cardiovascular mortality and morbidity. Entry criteria include a sustained sitting systolic blood pressure of 160 to 219mm Hg plus a sustained sitting diastolic pressure of 95 to 109mm Hg. Also required is a standing systolic blood pressure of at least 140mm Hg. Patients must give their informed consent, and be free of congestive heart failure requiring treatment, gout, renal failure or a recent cerebral haemorrhage. Patients are to be randomised to 3 groups-(i) no treatment; (ii) treatment with a diuretic [bendroflumethiazide (bendrofluazide)]; or (iii) treatment with an angiotensin converting enzyme (ACE) inhibitor (lisinopril). Starting dosage for bendroflumethiazide and lisinopril is 2.5 mg/day. In order to achieve goal sitting systolic and diastolic blood pressures (< 150/80 mm Hg), a doubling of the dosage is allowed. Furthermore, slow release diltiazem (120 mg/day increasing to 240 mg/day if required) may be added to the medication of the actively treated groups. These drugs have been chosen as inexpensive and appropriate representatives of their therapeutic classes. 700 patients in each group (a total of 2100) will be sufficient to detect a 40% difference in cerebrovascular events between no treatment and active treatment (alpha = 0.01, 1-beta = 0.90). These numbers will also detect a difference in total mortality of 25% and in cardiovascular mortality of 35%. The pilot phase of the trial has been started with support from the British Heart Foundation. Centres which are interested in taking part should contact C.J. Bulpitt or any of the other authors.

Aged↗
PubMed1994

Hypertension caused by low-level lead exposure: myth or fact?

BACKGROUND: Several reports on the possible association between low-level lead exposure and blood pressure reflect diverging views. This meta-analysis aimed to find a common denominator in the published literature and to estimate whether a relationship exists between blood pressure and levels of lead in the blood. METHODS: Of the studies reviewed, 23 provided sufficient details to be considered. The meta-analysis included 33 groups with a total of 33 141 subjects, who had been recruited from the general population in 13 surveys and from occupational groups in 10 studies. In all but four studies the results were adjusted for age, and most studies took into account additional confounding factors. RESULTS: The association between blood pressure and blood lead was similar in both men and women. In the combined studies, a twofold increase in blood lead concentration was associated with a 1.0 mmHg rise in systolic pressure (confidence interval 0.4-1.6 mmHg; P = 0.002) and with a 0.6 mmHg increase in diastolic pressure (confidence interval 0.2-1.0 mmHg; P = 0.02). The association with systolic pressure strongly relied on the inclusion of a large study (n = 3851) in which women's blood pressure was measured at the end of pregnancy. The association with diastolic pressure was largely due to a population survey in the USA (n = 6289). There was no relationship across studies between the strength of the blood pressure-blood lead relationship and the mean blood lead concentration. CONCLUSION: The published evidence suggests that there can only be a weak positive association between blood pressure and lead exposure. Any such relationship may not be causal and is unlikely to entail any public-health implication in terms of hypertension-related complications. Nevertheless, these assumptions need to be confirmed in prospective population studies.

Blood Pressure↗
PubMed1994

Why is antihypertensive drug therapy needed in elderly patients with systolodiastolic hypertension?

OBJECTIVE: This paper presents a meta-analysis of eight outcome trials of antihypertensive drug treatment in elderly hypertensive patients, and uses the results of these trials to discuss day-to-day issues in the treatment of elderly hypertensive patients. META-ANALYSIS: In an intention-to-treat analysis, cardiovascular mortality was decreased on average by 22% (95% confidence interval -32% to -10%). This decrease was a result of reductions in both coronary and cerebrovascular mortality, by 26% (-40% to -9%) and 33% (-50% to -9%), respectively. So far, the effectiveness of antihypertensive therapy in reducing cardiovascular mortality has not been established with confidence in trials where the diastolic blood pressure at random allocation to treatment groups was below 95 mmHg or in patients above 75 years of age. IMPLICATIONS FOR DAY-TO-DAY PRACTICE: No blood pressure treatment goal has been definitively established but a reduction in systolic blood pressure to about 150 mmHg may be optimal. Extrapolation of trial results to the elderly population with systolodiastolic hypertension at large seems acceptable for a Western population, but may be premature for elderly Asians and Africans. beta-Blockers and especially diuretics are recommended as first-line drugs in elderly patients with symptomless, uncomplicated hypertension, since the effectiveness of other drugs in reducing morbidity and mortality has not yet been established. Recommendations for the treatment of symptomless patients with isolated systolic hypertension may be premature. Ongoing trials on systolic hypertension in Europe (Syst-Eur) and China (Syst-China) may provide further information.

Aged↗
PubMed1994

Early definitive operation for bleeding peptic ulcer.

Thirty-one patients operated on for bleeding peptic ulcer were reviewed. The concept was to make an early decision to operate and proceed as soon as the patient was haemodynamically stable. In addition to haemostasis, a definitive operation was performed. Seventeen general surgeons performed the operations. Twenty-four patients (77%) were operated on within the first 24 h. During the hospital stay, two deaths (6%) occurred; four patients (13%) re-bled postoperatively, all of whom had a second operation. During a mean follow-up of 45 months, 12 deaths occurred unrelated to peptic ulcer disease and one patient had recurrent bleeding. Proximal gastric vagotomy (PGV) was used in 10 of the 14 duodenal ulcers (71%) without any hospital mortality; one patient re-bled after the operation and another during the follow-up. These results support the view that early surgery achieves a low hospital mortality and a PGV achieves good results even when carried out by several general surgeons.

Adolescent↗
PubMed1994

Lack of association between the I/D polymorphism of the angiotensin-converting enzyme gene and essential hypertension in a Belgian population.

We tested the insertion/deletion (I/D) polymorphism of the ACE gene in 119 hypertensive patients and in 109 normotensive controls by means of the polymerase chain reaction (PCR). The allele and genotype frequencies of the I/D polymorphism in the ACE gene are essentially identical in both groups, regardless of age or sex. The I/D polymorphism of the ACE gene is thus not implicated in Belgian hypertensive patients.

Base Sequence↗
PubMed1994

Factors predisposing to further hemorrhage and mortality after peptic ulcer bleeding.

BACKGROUND: The mortality rate of peptic ulcer hemorrhage has remained unchanged, mainly attributable to rebleeding in an increasingly elderly population. It has been advocated that early identification of patients at high risk of rebleeding with subsequent prompt therapy may reduce the rebleeding and mortality rates. This study examines the value of clinical factors and endoscopic findings in the prediction of further hemorrhage and death. STUDY DESIGN: One hundred fifty-seven patients admitted over a two year period with bleeding from peptic ulcer were reviewed. The predictive value of individual risk factors in identifying those patients at risk of further hemorrhage or dying was determined by the chi-square test with a Yates correction. RESULTS: Nineteen patients died, 37 had further bleeding, and 31 had an early operation. Shock was the factor that best predicted further bleeding. Other significant factors were a transfusion requirement of more than four units of blood during the first 48 hours and endoscopic stigmata of recent hemorrhage. The number of coexisting illnesses per patient was strongly related to fatality rate. Other factors indicative of an increased mortality rate included steroid use, onset of bleeding during the period of hospitalization, alcohol use, further bleeding, and a need for more than four units of blood transfused during the first 48 hours. CONCLUSIONS: Shock remains the most valuable sign in predicting further bleeding and is superior to endoscopic stigmata. The close relationship between the mortality rate and coexisting illness emphasizes the fact that the most deaths result from nonpeptic ulcer disease.

Aged↗
PubMed1994

Efficacy and safety of pravastatin in hypertensive hypercholesterolaemic patients on antihypertensive drug therapy.

This double-blind, placebo-controlled, six month trial evaluated the efficacy and safety of pravastatin in hypercholesterolaemic, hypertensive patients on antihypertensive treatment, who on a standard lipid-lowering diet maintained a plasma total cholesterol level of at least 250 mg%. Fifty hypertensive patients were randomised to placebo or pravastatin treatment. Once daily dosing consisted of 10 mg pravastatin during the first month, 20 mg during the second month and 40 mg during an additional 4 months or matching placebos. Compared with placebo, pravastatin reduced (P < 0.001) the plasma level of total cholesterol, LDL-cholesterol and phospholipids during the six month study period whereas plasma HDL-cholesterol and triglycerides did not change significantly. These changes in plasma lipids were independent of age and of the nature of the concomitant antihypertensive treatment. No serious side-effects were observed and pravastatin was generally well tolerated. In conclusion, pravastatin 10-40 mg once daily reduced plasma total and LDL-cholesterol in hypercholesterolaemic, hypertensive patients, independent of age and concurrent antihypertensive drug therapy.

Adolescent↗
PubMed1994

Differences between black and white persons in blood pressure and related biological variables.

In societies with several ethnic groups the prevalence of hypertension is abnormally high in black subjects. In addition, blacks are more susceptible to the consequence of high BP. Compared with whites plasma renin is low in blacks independently of age, the level of BP and dietary sodium consumption. No abnormal mineralocorticoid level has ever been consistently reported in blacks to account for their low renin. However potassium intake, prostaglandin and kallikrein excretions are low in blacks and black/white differences exist in the distribution of the restriction fragment length polymorphism at the gene loci for renin. It is hypothesised that the low renin and the propensity of blacks to hypertension result from elevated free cytosolic calcium. Indeed several factors inducing or associated with an increased cytosolic calcium cluster in blacks, e.g. sodium pump inhibition, high intracellular sodium concentration, low plasma ionised calcium, high parathyroid hormone. Furthermore, intensive calcium mobilisation from intracellular stores in response to circulating serum agonists as observed in skin fibroblasts of blacks might be contributive should it occur in all cells including vascular smooth muscle and juxtaglomerular cells.

Black People↗
PubMed1994

Number of measurements required for the analysis of diurnal blood pressure profile.

The aim of this study was to investigate how frequent blood pressure (BP) readings need to be obtained to reproduce the diurnal BP profile without loss or distortion of information. The subjects were 97 normotensives aged 23-84 years. Noninvasive ambulatory BP readings were programmed with an interval of 7.5 minutes during the day (from 8 am to 8 pm) and at 15 minutes intervals at night. Readings were stepwise omitted from the original recordings. For each step the diurnal BP profile was modelled with five different techniques. The concordance between original and reduced recordings was quantified using the repeatability coefficient, i.e. twice the standard deviation of the differences between these recordings (expressed as a percentage of the 5th to 95th percentile range of the parameter under investigation). The concordance between original and reduced recordings tended to be better for the level of pressure than for the parameters of the diurnal profile. If the sampling frequency was two readings per hour, concordance for SBP was < 10% for the BP level, 19% for the 24h standard deviation, 12% for the nocturnal fall in BP, 23% for the amplitude of the Fourier curve and 17% for the cusum derived circadian alteration magnitude. Concordance worsened to > 25% for most parameters of the diurnal BP curve when the interval between consecutive measurements exceeded 30 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Erythrocyte cation transport systems in insulin-dependent diabetics: correlation with prorenin and albuminuria.

The relationship between erythrocyte cation transport systems, plasma prorenin and albuminuria was examined in patients with insulin-dependent diabetes mellitus (IDDM). Different measurements of erythrocyte transport systems were obtained in patients with IDDM: Na+/Li+ countertransport; Na+/K+ cotransport and Na+/K+ ATPase pump activity. In single regression analysis the erythrocyte Na+/Li+ countertransport was positively related to the plasma prorenin level. In multiple regression analysis the erythrocyte Na+/Li+ countertransport activity was independently related to plasma prorenin, albuminuria and age. Our data in patients with IDDM show that an elevated erythrocyte Na+/Li+ countertransport is accompanied by a higher plasma prorenin level and albuminuria.

Adult↗
PubMed1994

[Biopsy of occult lesions detected by mammography in a district hospital].

Most series of biopsies of mammographically identified breast lesions are performed in specialized units following mass screening and report an 11% to 36% rate of carcinoma. The results of such biopsies in a district hospital setting are analysed. Seventy-nine consecutive needle localisation biopsies were performed over a 2.5-year period by 15 surgeons and retrospectively reviewed. 13 lesions (16%) were referred by the National Breast Screening Programme. Carcinomas were found on 24 biopsies (30%): 8 were in situ and 16 were infiltrative, 5 of whom were less than 0.5 cm. Thus half of them met the criteria of "minimal" carcinoma as described by GALLAGHER. 40% of women 50 years and older and 13% of women less than 50 years had carcinoma. 6% of the lesions read on mammogram as "probably" benign and 47% of those considered as "probably" malignant were cancer. There was no significant correlation between the mammographic appearance and the occurrence of cancer but all "minimal" invasive carcinomas were associated with calcifications. Complete removal of the lesion failed in 3 cases. Localisation biopsy can be performed in a district hospital by general surgeons with a similar yield of malignancies as in specialized unit and with a high incidence of early detected cancers.

Adult↗
PubMed1994

[Risk factors of persistent or recurrent bleeding and mortality in peptic ulcer hemorrhage].

The mortality rate of peptic ulcer haemorrhage has remained unchanged, mainly attributed to rebleeding in an increasingly elderly population with more coexisting systemic diseases. The value of clinical factors and endoscopic findings in predicting in-hospital further haemorrhage and death are analysed. Over a 2-year period, 157 consecutive patients were admitted with bleeding from peptic ulcer, 19 died and 37 had further bleeding. The predictive value of each factor was determined by the chi 2 test with a Yates-correction (significant, p < 0.05). Significant predictive factors of further bleeding were shock, a transfusion requirement > 4 units during the first 48 hours and endoscopic stigmata of recent haemorrhage. The combination of these factors was not of better predictive value than shock alone. The number of coexisting illnesses per patient was strongly related to fatality rate. Other significant factors indicative of an increased mortality included steroid, onset of bleeding during a hospital stay, alcohol, further bleeding, and > 4 units transfused over the first 48 hours. Shock remains the most valuable sign in predicting further bleeding and is superior to endoscopic stigmata. The close relationship between the mortality rate and coexisting illnesses underlines the fact that the majority of deaths result from non peptic ulcer disease.

Aged↗
PubMed1994

A consistent reference frame for ambulatory blood pressure monitoring is found in different populations.

This study investigated the consistency of a reference frame for ambulatory pressure monitoring, which using various approaches was determined in two different populations. The two reference groups were 718 subjects randomly selected from the population and 895 bank employees. The reference values derived in these two groups were subsequently tested in 591 untreated hypertensive patients. The ambulatory pressures equivalent to a conventional pressure of 140 mmHg systolic and 90 mmHg diastolic were calculated by regression analysis in all subjects. In addition, in subjects who were normotensive by conventional sphygmomanometry, the mean +2 and +3 standard deviations and the 90th, 95th and 99th percentiles of the ambulatory measurements were determined. The distributions of the ambulatory measurements were similar in the two reference groups and the aforementioned parameters therefore agreed within 4 mmHg in the two populations. There was considerable overlap in the ambulatory pressures between the two reference groups and the hypertensive patients. Classification of the patients according to the means +3 standard deviations and the regression limits gave the same results because in both reference groups these boundaries approximated to each other within 1 mmHg. For the 24 h pressures in the population sample these boundaries were 140 mmHg systolic and 88 mmHg diastolic. Of the patients with systolic hypertension (> or = 160 mmHg on conventional measurement), 39% had a 24 h systolic pressure of < 140 mmHg and of those with diastolic hypertension (> or = 95 mmHg), 44% had a 24 h diastolic pressure of < 88 mmHg; if the corresponding boundaries derived in the bank employees (143/90 mmHg) were applied, these proportions were 47% and 44%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗