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Biomedical subjects

A A Ajayi

Publications and source records attributed to A A Ajayi.

At least 37 records · Page 2Linked to original sources
PubMed1996

Oral therapy with combined enalapril, prazosin and hydrochlorothiazide in the acute treatment of severe hypertension in Nigerians.

OBJECTIVE: The efficacy, safety, tolerability and speed of onset of the hypotensive action of the combination of oral enalapril (10 mg) prazosin (1 mg) and hydrochlorothiazide (50 mg) has been assessed in 12 Nigerians with severe hypertension (Diastolic BP > or = 115 mmHg). PATIENTS: The ages of the patients ranged from 30-60 years, and the serum creatinine from 52-732 mumol.l-1. The initial blood pressure was 200/130 mmHg. RESULTS: The combination significantly reduced systolic and diastolic blood pressure respectively. The hypotensive action appeared within 0.5 h and led to a fall in BP to 175/120 mmHg, and the peak action occurred at 4 h, when the BP was 138/99 mmHg, and it persisted upto 24 h (160/101 mmHg). Despite the significant fall in blood pressure, no reflex tachycardia was observed. Transient dizziness was seen in 2 patients, but otherwise all claimed improvement in clinical status and a clearer sensorium. CONCLUSION: The combination may be a useful oral treatment for the rapid control of severe hypertension in Blacks.

Administration, Oral↗
PubMed1996

A three year clinical review of the impact of angiotensin converting enzyme inhibitors on the intra hospital mortality of congestive heart failure in Nigerians.

Angiotensin converting enzymes inhibitors are now regarded as the cornerstone of congestive heart failure therapy owing to established reduction in mortality and the symptomatic amelioration following their use. Although the response to converting enzyme inhibitor therapy may be influenced by race, we have reported a trend to reduce intra hospital mortality, the correction of hyponatremia and shortened hospitalization in Nigerians treated with converting enzyme inhibitors. We have now conducted an extended retrospective study, to evaluate the trends in the use of enalapril or captopril and its impact on prognosis in Nigerian patients with heart failure alone, admitted between January 1992 to December 1994. The proportion of heart failure treated with (captopril or enalapril) increased from 37pc in 1992, to 50pc in 1993, to 65pc in 1994. The demographic variables and cause of heart disease were similar in patients treated with converting enzyme inhibitors (n = 55) and those treated conventionally (n = 36). The cumulative mortality among converting enzyme inhibitors treated patients, was (8/55, 14pc) compared to patients not treated (17/36, 48pc) x2 = 12.4; p < 0.0001. There was no sex predilection in mortality (M = 25pc, F = 28pc, mean 27pc). However, initial serum Na+,125mmol was significantly (x2 = 11.1; p < 0.001) more common in the dead patients, 25pc compared to the survivors discharged home 7.5pc. The median hospital stay was 17 days in captopril treated survivors (range two to 44 days) and 19 days (range four to 67 days) in conventionally treated patients. Thus converting enzyme inhibitor therapy may reduce intra hospital mortality in Black Africans hospitalized for congestive heart failure and shorten hospital stay, despite the epidemiologically low plasma renin in Blacks. Hyponatremia may be a poor prognostic index in heart failure in our patients, and its reversal by converting enzyme inhibitors may reflect neurohormonal inhibitor. Earlier and more wide spread use of angiotensin converting enzyme inhibitors in Nigerian and Black Africans with chronic heart failure is now clearly indicated.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Testosterone increases human platelet thromboxane A2 receptor density and aggregation responses.

BACKGROUND: The incidence of thrombotic cardiovascular disease is greater in men than in premenopausal women. Testosterone has been implicated as a significant risk factor for cardiovascular disease and for acute myocardial infarctions and strokes in young male athletes who abuse anabolic steroids. Thromboxane A2 (TXA2) is a vasoconstrictor and platelet proaggregatory agent that has been implicated in the pathogenesis of cardiovascular disease. We therefore tested the hypothesis that testosterone regulates the expression of human platelet TXA2 receptors. METHODS AND RESULTS: In a double-blind, placebo-controlled, randomized, parallel-group study, we determined the effects of testosterone cypionate 200 mg IM given twice, 2 weeks apart, or saline placebo in 16 healthy men. Platelet TXA2 receptor density (Bmax) and dissociation constant (Kd) were measured by use of the TXA2 mimetic 125I-BOP. Platelet aggregation responses to I-BOP and to thrombin and plasma testosterone concentrations were measured before treatment (pretreatment phase), at 2 and 4 weeks (active phase), and again at 8 weeks (recovery phase). Treatment with testosterone was associated with an increase in the Bmax value from 0.95 +/- 0.13 to 2.10 +/- 0.4 pmol/mg protein (n = 9), with a peak effect at 4 weeks (P = .001), returning to baseline by 8 weeks. There was no significant change in Bmax values in the saline-treated group. The Kd values were unchanged. Testosterone treatment was associated with a significant increase in the maximum platelet aggregation response to I-BOP (P < .001) at 4 weeks and returned to baseline at 8 weeks. The EC50 values were not significantly changed. Platelet TXA2 receptor density was positively correlated (r = .56, P < .001, n = 32 measurements) with pretreatment (endogenous) plasma testosterone levels (range, 215 to 883 ng/dL) but not Kd. CONCLUSIONS: Testosterone regulates the expression of platelet TXA2 receptors in humans. This may contribute to the thrombogenicity of androgenic steroids.

Adult↗
PubMed1995

Disproportionate intraventricular septal hypertrophy in Nigerians with essential hypertension.

It is not clear how frequently hypertrophic cardiomyopathy coexists with essential hypertension or whether chronic hypertension per se, induces hypertrophic cardiomyopathy (hypertensive hypertrophic cardiomyopathy). Eighty-three Nigerians with essential hypertension alone underwent M-mode and 2 dimensional echocardiographic study. Twenty per cent (17 patients) had disproportionate intraventricular septal hypertrophy (septum: posterior wall ratio > or = 1.4). These subgroup tended to be elderly, with average age of 57.7 years, and were predominantly male (70%). Two patients in this subgroup (2.4% of total) additionally had thickened posterior left ventricles and a hyperdynamic left ventricular systolic function (fractional fibre shortening of > or = 45%). This picture is consistent with "hypertensive hypertrophic cardiomyopathy". Routine echocardiography may permit the early identification and thus a closer scrutiny and follow up of essential hypertensive patients with disproportionate septal thickness. The prognostic implications of this requires long term study.

Adult↗
PubMed1995

The efficacy and tolerability of amlodipine and hydrochlorothiazide in Nigerians with essential hypertension.

The efficacy and safety of the novel calcium antagonist Amlodipine (Pfizer Laboratories, New York, New York) and hydrochlorothiazide were evaluated and compared in a randomized, single-blind, parallel group study in black Africans with essential hypertension. Twenty Nigerians with newly diagnosed mild to moderate essential hypertension were randomized to receive ascending doses of Amlodipine (5 mg and 10 mg) or hydrochlorothiazide (25 mg or 50 mg), and blood pressure and heart rate were measured at baseline and at 2, 4, and 6 weeks of therapy. Both Amlodipine and hydrochlorothiazide significantly reduced supine and erect blood pressure. Supine blood pressure on Amlodipine fell from a mean of 190/104 mm Hg to 150/79 mm Hg, and on thiazide from 180/103 mm Hg to 141/84 mm Hg. There was, however, no significant difference between both drugs in antihypertensive efficacy. Neither drug induced a reflex increase in heart rate. The fall in blood pressure on both agents was associated with an increase in plasma urea. Amlodipine induced no change in plasma potassium, but hydrochlorothiazide caused hypokalemia. Both agents were well tolerated, and Amlodipine should undergo further study in the treatment of hypertension in blacks.

Amlodipine↗
PubMed1995

Plasma lipids, lipoproteins, and apolipoproteins in Nigerian diabetes mellitus, essential hypertension, and hypertensive-diabetic patients.

Plasma lipids, lipoproteins, and apolipoproteins were assessed in three groups of Nigerians at increased risk for atherosclerotic heart disease. The three patient groups, diabetes mellitus (n = 15), essential hypertension (n = 12), and hypertensive-diabetes mellitus (n = 11), were compared with age-matched, apparently healthy controls (n = 14). In subjects with diabetes mellitus, triglyceride and its related apolipoproteins CIII and CIII:NonB were significantly higher than controls. High-density lipoprotein cholesterol (HDL-C) was significantly lower; its related ratios, total/HDL-C and low-density lipoprotein cholesterol (LDL-C)/HDL-C were significantly higher than those for controls. Subjects with hypertension and hypertensive-diabetes mellitus had significantly higher values than controls for those lipids and lipid fractions considered atherogenic (total cholesterol, LDL-C, triglyceride, and the total/HDL-C and LDL-C/HDL-C ratios) as well as apolipoproteins B, CIII, and lipoprotein particles Lp(a) and CIII:NonB. Only hypertensive-diabetes mellitus subjects had lower HDL-C levels, while hypertension patients had significantly higher apolipoprotein AI and LpAI concentrations than controls. Subjects with hypertensive-diabetes mellitus had significantly worse lipid, lipoprotein, and apolipoprotein profiles both in terms of increased atherogenic and reduced anti-atherogenic parameters compared with subjects with diabetes mellitus or hypertension only. These studies suggest that Nigerians with diabetes, hypertension, and especially both hypertension and diabetes need to be fully evaluated from a lipid and lipoprotein standpoint, and any abnormalities detected need to be taken into consideration during therapy of this group of high-risk patients.

Adult↗
PubMed1994

Acute cardiovascular effects of the concurrent administration of enalapril, prazosin or amlodipine in healthy Nigerians.

The acute circulatory effects of the combination of prazosin 1 mg, enalapril 10 mg or amlodipine 5 mg were evaluated and compared in a placebo controlled, randomised, double blind, latin-square, cross-over study in 8 normotensive healthy Nigerians. Supine and erect blood pressure were reduced by the active treatment combinations (F = 8.8, P = 0.0006, analysis of variance). In all, the onset of blood pressure fall was within 2 h, with a peak reduction at 4-6 h and persisting for at least 12 h. The combination of converting enzyme inhibitor and alpha blocker, however, caused a significantly greater hypotensive action than the other combinations (P < 0.05, analysis of variance). There was a modest reflex tachycardia in the erect position on all treatments (P = 0.008). Cardiac autonomic reflexes or left ventricular echocardiographic indices were unaffected by the drug combinations. The haemodynamic effect of enalapril plus prazosin combination, which separately cause little hypotensive effect in Africans, may reflect an important pharmacodynamic interaction between alpha 1 and angiotensin II vascular receptors. All combinations lower blood pressure and warrant further study in Nigerian hypertensives. However, the enalapril plus prazosin combination caused the greatest blood pressure fall, and caution is indicated during their concurrent use, owing to enhanced first dose hypotension.

Adult↗
PubMed1994

Possible evidence of angiotensin II and endogenous opioid modulation of novelty-induced rearing in the rat.

Rats treated with captopril (CAP, 10mg/kg i.p.) naltrexone (Nalx 0.1 mg/kg i.p) and saralasine (100 micrograms/kg i.p) displayed significantly less novelty-induced rearing (NIR) compared to saline injected animals. Naltrexone potentiated the inhibitory effect of CAP on NIR. Pretreatment with NALX did not alter SARA-induced decrease in NIR. It is suggested that the endogenous release of AII and/or opioids somehow modulate basal rearing activity.

Angiotensin II↗
PubMed1993

Spectrum of hypertensive heart disease in Nigerians: cross-sectional study of echocardiographic indices and their correlation with treadmill exercise capacity.

OBJECTIVES: The aims of this study were to provide cross-sectional data on echocardiography in Nigerians with normotension, essential hypertension and hypertensive heart failure, and to correlate the echocardiographic indices with treadmill functional capacity. METHODS: M-mode and two-dimensional echocardiography and a Bruce protocol treadmill test were undertaken in Nigerians with essential hypertension (n = 22) and hypertensive heart failure (n = 12), and in matched healthy volunteers (n = 15). RESULTS: A striking echocardiographic feature was the tendency to eccentric or asymmetric left ventricular hypertrophy in Nigerians. The septum to posterior wall ratios were 1.4 +/- 0.1 in the normotensives, 1.6 +/- 0.1 in the hypertensives and 1.5 +/- 0.1 in the heart failure group. There was a progressive increase in left ventricular mass index and a reduction in fractional fibre shortening in the hypertensive spectrum. Treadmill exercise capacity also showed a progressive fall from normotensives through hypertensives to the heart failure group. A significant positive correlation was found between fractional fibre shortening and treadmill time in the heart failure group. CONCLUSION: In Nigerians with hypertensive heart disease, there was a striking tendency for eccentric (asymmetric) rather than concentric left ventricular hypertrophy. Systolic left ventricular contractility may be predictive of treadmill exercise capacity in hypertensives.

Cardiac Output, Low↗
PubMed1993

A prospective study of chloramphenicol induced aplastic anaemia in Nigerians.

A five-year prospective study of chloramphenicol induced aplastic anaemia in Nigerians was undertaken. Five proven cases were seen, representing 45.5% of all cases of aplastic anaemia diagnosed during the period of study and 1.0 cases per year. Chloramphenicol induced aplastic anaemia is rare (only 0.002% of all new non-obstetric patients seen in the hospital during the period of study) but preventable. Restriction of the drug or its total withdrawal is recommended.

Adolescent↗
PubMed1992

The influence of captopril on intrahospital mortality and duration of hospitalization in Nigerians with congestive heart failure.

A retrospective study was undertaken to evaluate the impact of captopril on intrahospital mortality and the duration of hospitalization in Nigerians with congestive heart failure. In 1989 and 1990, the mortality rates were 13.7% and 15.2%, respectively, and it appeared to be reduced to 6.6% in 1991 after the introduction of captopril. There was a significant (p less than 0.001) increase in the proportion of patients with early discharges (less than 10 days hospitalization) following the addition of captopril to the standard antifailure regime in Nigerians.

Captopril↗
PubMed1992

A cross-sectional study of echocardiographic indices, treadmill exercise capacity and microvascular complications in Nigerian patients with hypertension associated with diabetes mellitus.

Associations between hypertension and cardiovascular complications of diabetes mellitus in Nigerians, were examined in a cross-sectional study. 20 hypertensive-diabetic patients, 16 hypertensive patients, 10 non-hypertensive diabetic patients and 10 age- and sex-matched healthy controls, underwent M-mode and cross-sectional echocardiography, and Bruce-protocol treadmill exercise performance. Left ventricular (LV) mass indices (+/- SD) were significantly higher in hypertensive patients (164 +/- 12gm-2), diabetic (158 +/- 17gm-2) and hypertensive diabetic patients (125 +/- 129gm-2) compared with normal controls (111 +/- 17gm-2) p < 0.01. However, the LV mass index in the hypertensive-diabetic patients was significantly less than in hypertensive (p < 0.05) or normotensive diabetic patients (p < 0.05). Systolic cardiac contractility measured as fractional fibre shortening, was preserved in the hypertensive patients (24 +/- 4%) compared with the healthy controls (23 +/- 4%), but was depressed in diabetic patients (19 +/- 3%) and to a greater extent in the hypertensive-diabetic patients (15 +/- 4% p < 0.01). Treadmill exercise tolerance time was reduced independently in hypertension (309 +/- 73 seconds) or diabetes (321 +/- 119 seconds), p < 0.05, but was further impaired in hypertensive-diabetic patients (289 +/- 110 seconds) p < 0.01 compared to the healthy controls (490 +/- 156 seconds). The patients with hypertension and diabetes had a greater degree of proteinuria (p < 0.001) and a higher frequency of retinopathy (p < 0.001), in comparison to those with hypertension or diabetes alone.

Blood Pressure↗
PubMed1992

The problem of follow-up of renal transplant patients in the tropics.

A 40-year-old male Nigerian with end-stage renal disease (ESRD) received a renal allograft from a live related donor, in the United Kingdom in 1986. Subsequently, in Nigeria, he developed recurrent episodes suggestive of chronic allograft rejection or allograft nephritis which necessitated hospitalisation in our establishment. He subsequently died during one such episode. The peculiar management problems and challenges posed by the patient during his recent admission in our clinical setting are discussed.

Adult↗
PubMed1991

Estimation of creatinine clearance from serum creatinine: utility of the Cockroft and Gault equation in Nigerian patients.

The predictive accuracy of the Cockroft and Gault equation in the assessment of creatinine clearance was evaluated in 30 Nigerian patients with hypertension, congestive heart failure, chronic renal failure and varying degrees of renal impairment. There was a high correlation between the measured and predicted creatinine clearance as shown by the regression equation: measured creatinine clearance = 0.84 predicted creatinine clearance +4.5 ml.min-1 (r2 = 0.74). The prediction error, reflecting the disparity between measured and calculated clearance was low at 2.0 (15.4) ml.min-1. Neither sex nor disease state or level of creatinine concentration had an important effect on the predictive value of the equation in Nigerians.

Creatinine↗