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Biomedical subjects

A A Ajayi

Publications and source records attributed to A A Ajayi.

At least 19 recordsLinked to original sources
PubMed2004

Alteration in endothelin receptor sub-type responsiveness and in the endothelin-TXA(2) mimetic U46619 interaction, in type-2 hypertensive diabetic Zucker rats.

BACKGROUND: Type-2 diabetes is characterized by endotheliopathy, which increases target organ damage and mortality. There is excessive endothelin-1 and TXA(2) production, and abnormal vascular reactivity to endothelin-1, manifested as a paradoxical hypotensive action in Zucker diabetic, but not lean rats. We examined the hypothesis that there is an alteration in the ET-A/ET-B receptor subtype sensitivity, and/or the interaction or cross-talk between ET-1 and TXA(2) in type-2 diabetes, using Zucker diabetic rats and their lean littermates. MATERIALS AND METHODS: Hemodynamic studies were performed in lean and Zucker fatty diabetic rats of both sexes. Laser doppler flowmetry was used to measure renal cortical (RCF) and medullary blood flow (MBF) responses. Dose response curves for mean arterial blood pressure (MAP), MBF and RCF in response to ET-1, U46619, acetylcholine, and L-NAME (25mg/kg) were constructed after pre-treatment of the rats with either BQ610 1mg/kg i.v. or BQ788 0.5mg/kg i.v. The effects of BQ610 and BQ788 on whole blood impedance aggregation were also assessed. RESULTS: BQ788, but not BQ610 abolished both the paradoxical hypotensive action of ET-1 in Zucker diabetic rats (n=7 each, P<0.001 ANOVA) as well as the dose-dependent rise in MBF (P<0.001 ANOVA). BQ788, but not BQ610 abolished the difference in response to ET-1 between lean and diabetic Zucker rats. U46619 caused a hypotensive action in male Zucker rats which was abolished by L-NAME 25mg/kg or indomethacin 10mg/kg i.v. The U46619 interaction with BQ788 on both MAP and MBF was significantly (P<0.03 ANOVA) different between lean and diabetic Zucker rats. BQ788, but not BQ610 attenuated both the MAP and MBF responses to acetylcholine or L-NAME P<0.02 ANOVA). However, BQ610 dose-dependently attenuated the slope of platelet aggregation in both lean and Zucker diabetic rats (P<0.02 ANOVA). CONCLUSION: ET-B receptor antagonism abolished the abnormal vascular reactivity and MBF responses to ET-1, and also normalized the vasoactive responses to the level seen in healthy lean Zucker rats. ET-1 receptor blockade influences the responses to TXA(2) receptor activation. In the systemic and renal circulation, this interaction appears to be mostly ET-B receptor mediated, whilst in platelets, ET-A receptor role may be predominant. The interaction or cross-talk between ET-1 and TXA(2) is altered in the type-2 diabetic state. Collectively, these pathophysiological changes may contribute to the vicious circle of diabetic endotheliopathy.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2004

Sex hormone regulation of systemic endothelial and renal microvascular reactivity in type-2 diabetes: studies in gonadectomized and sham-operated Zucker diabetic rats.

BACKGROUND: Male Zucker diabetic rats exhibit a more severe endotheliopathy in comparison with their female diabetic litter mates. The plasma concentrations of both thromboxanes and endothelins are elevated in diabetes, and the receptor cross-talk between TXA(2) and ET-1 receptors may be enhanced in type-2 diabetic Zucker rats. AIMS: To determine the role of the endogenous sex steroid hormones, testosterone and estradiol on the systemic and renal microvascular reactivity to ET-1, thromboxane-mimetic U46619, ET-TXA(2) receptor interaction, and the nitric oxide vasodilator system in Zucker hypertensive-diabetic rats. METHODS: Male and female Zucker rats aged 8-10 weeks were each divided into two groups. The male rats were castrated or underwent a sham operation. The female rats were spayed (bilateral ovariectomy and hysterectomy) or had a sham operation. All rats were studied 4-6 weeks after the gonadectomy or sham operations. Blood glucose and insulin as well as plasma concentrations of testosterone and estradiol were determined. Haemodynamic studies were undertaken with determination of the dose-response curve for mean arterial pressure (MAP), renal cortical flow (RCF) and renal medullary blood flow (MBF) in response to ET-1 and U46619, and the effect of interdiction of the ET-TXA(2) interaction with ET-antagonists BQ610 and BQ788. The role of endogenous NO was assessed by its response to graded acetylcholine doses and to a L-NG-nitro-arginine methyl ester (L-NAME) infusion. RESULTS: Castrated male rats had a significantly lower blood glucose concentration (295 +/- 33 mg dL(-1)) compared with their sham-controls (481 +/- 40 mg dL(-1)), P = 0.008. Mean arterial pressure tended to be lower in the castrated rats. Gonadectomy reduced the plasma testosterone and estradiol concentrations. Castration abolished the hypotensive action of U46619 compared with sham-operated male rats (P < 0.0001, anova). Conversely, the pressor action of U46619 seen in the sham-operated female rats was reversed to a profound hypotensive action in the spayed rats (P < 0.001, anova). The change in MAP after U46619 was inversely correlated to the plasma testosterone concentration (r = -0.73, P = 0.027). The paradoxical hypotensive response elicited by ET-1 in the Zucker diabetic rats of both sexes was abolished by castration only (P < 0.005, anova). Castration caused a significant (P = 0.011) augmentation of the vasodilator response to acetylcholine, while spaying caused a slight attenuation. Castration, but not spaying, resulted in significant increases in MBF after U46619 (P = 0.003, anova), ET-1 (P = 0.005, anova) and acetylcholine (P = 0.053, anova). The ET-(B) antagonist BQ788 augmented the U46619-induced rise in MAP in castrated male rats, and also abolished the U46619-induced increase in MBF (P < 0.01 anova). L-NAME (25 mg kg(-1)) increased MAP and decreased MBF in the gonadectomized and sham-operated rats, except for the castrated male Zucker rats, where it significantly increased MBF (+90 +/- 31 PU) (P = 0.0004, anova) despite the increase in MAP. CONCLUSIONS: Testosterone and estradiol regulate systemic and microvascular reactivity to TXA(2) receptor stimulation in type-2 diabetic Zucker rats. The impact of testosterone on blood glucose concentration, blood pressure, and the systemic and renal microcirculatory response to ET-1 and NO, as well as the endothelin-thromboxane receptor cross talk, is greater, and opposite to that of estradiol. The effects of testosterone withdrawal may at least in part be mediated by the ET-B receptor subtype and NO generation. Androgen blockade should be investigated further for the reversal or delay of hypertensive-diabetic endotheliopathy.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2004

Endogenous opioids, mu-opiate receptors and chloroquine-induced pruritus: a double-blind comparison of naltrexone and promethazine in patients with malaria fever who have an established history of generalized chloroquine-induced itching.

AIMS: Chloroquine induces a severe generalized pruritus, in predisposed Black African patients, during treatment of malaria fever, and also in some Caucasian patients treated for rheumatological diseases. We have previously shown that chloroquine may release endogenous opioids and/or interact with micro-opiate receptors in rats, and that both histamine and malaria parasite blood density, contribute to the itching severity in malaria fever in humans. The aim of our present study was to assess and compare the antipruritic efficacy of the micro-opiate receptor antagonist, naltrexone, and the antihistamine, promethazine, in chloroquine treated patients with malaria fever. METHODS: A double-blind, randomized, parallel group comparison of the chloroquine-induced pruritus intensity and time profile in patients with parasitologically proven malaria fever, who were pretreated with a single dose of either naltrexone 50 mg or promethazine 25 mg orally (six patients each). All patients had an established history of severe pruritus following chloroquine treatment of malaria fever. A self-assessed itching severity score was undertaken at 0, 6, 12, 24, 48 and 72 h after initial chloroquine dosing, and the areas under the pruritus-intensity time curve AUCP0-72 h was determined in each patient and correlated to the malaria parasite density in blood. RESULTS: Both naltrexone and promethazine subjectively reduced itching severity compared with prior historical experience. One patient on naltrexone and two on promethazine never experienced any itching. There was no statistically significant treatment effect, but a significant time effect (P = 0.001, F = 4.77 d.f. 5) by two-way repeated measures ANOVA. The AUCP for naltrexone was 82 +/- 25 units/h, and 57 +/- 34 units/h for promethazine [95% confidence interval for the difference being -73 to 123]. However, the malaria parasite density in the naltrexone group (740 +/- 178 microl(-1)) tended to be higher than in the promethazine group 314 +/- 69 microl(-1) (P = 0.056, 95% confidence interval for the difference being -15 to 866 microl(-1)). Correction of the AUCP for malaria parasite density (parasite pruritogenic index, AUCP. units/h/parasites/microl blood) tended to be lower with naltrexone 9.1 +/- 2.6 than with promethazine 12.2 +/- 7.0 There was a highly significant and positive correlation between the malaria parasite density and the AUCP0-72 h, on naltrexone (r2 = 0.78, P = 0.040) and promethazine (r2 = 0.93, P = 0.008). However, comparison of regressions revealed that the slope of the regression was significantly steeper with promethazine 0.48 than naltrexone 0.12 (P = 0.006, t = 4.2), with the intercepts showing a trend to a difference (P = 0.086). CONCLUSION: Naltrexone exerted an antipruritic action, at least to a similar extent to promethazine in patients with chloroquine-induced itching in malaria fever. However, the relationship between parasite density and resultant pruritus was significantly different between naltrexone and promethazine. Thus, micro-opiate receptors/and or endogenous opioids may contribute to chloroquine itching in malaria fever, in humans, in accord with animal experimental findings. Malaria parasite density in blood is a strong determinant of itching severity in patients predisposed to chloroquine-induced pruritus.

Administration, Oral↗
PubMed2003

Gender difference in vascular and platelet reactivity to thromboxane A(2)-mimetic U46619 and to endothelial dependent vasodilation in Zucker fatty (hypertensive, hyperinsulinemic) diabetic rats.

We examined the hypothesis that gender differences exist in platelet and vascular reactivity in type-2 diabetes mellitus, using Zucker fatty diabetic rats of both sexes and their lean littermates. Type-2 diabetes is characterized by excessive platelet production of TXA(2), which is thrombogenic. Testosterone up-regulates platelet TXA(2) receptors and the aggregation response to thromboxane mimetics. Conversely, estrogen increases vascular nitric oxide (NO) production and inhibits platelet aggregation. Hemodynamic studies were undertaken with the determination of dose-response curve for MAP and renal cortical blood flow (RCF) in response to U46619, angiotensin-II, phenylephrine and endothelin-1, as well as the systemic hemodynamic response to acetylcholine and L-NG nitro-arginine methylester (L-NAME). Platelet aggregation response was evaluated using whole blood impedance aggregometry. There were significant gender differences in the systemic blood pressure and RCF response to TXA(2)-mimetic U46619 and angiotensin-II (P<0.02, ANOVA) but not to phenylephrine or endothelin-1. Male rats exhibited a paradoxical hypotensive response to U46619 (-18+/-11 mmHg) compared with a peak pressor response of +6+/-1 mmHg in female rats (P<0.01, ANOVA). The male rats exhibited an attenuated systemic vasodilator response (P<0.001, ANOVA) to acetylcholine (fall in MAP in male diabetic rats being -24+/-8 mmHg, compared with a fall of -50+/-8 mmHg in females), but a greater rise in the renal cortical resistance in response to NO inhibition by L-NAME (P<0.03) compared with the female rats. Both the slope (46+/-2) and the peak magnitude of the U46619-induced whole blood platelet aggregation (13+/-1) ohms were significantly higher (P<0.01, ANOVA) in male (n=10) compared with female diabetic rats (n=8) (29+/-0.8 slope, 10.0+/-0.8 ohms, respectively). Thus, the male diabetic Zucker rats exhibited an impaired response to vasoconstrictors (U46619 and angiotensin-II) and to endothelial (NO)-mediated vasodilation. The male gender may therefore be associated with the greater prothrombotic activity and a worse impairment of endothelial reactivity in the type-2 diabetic state.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2003

Endothelin-like action of Pausinystalia yohimbe aqueous extract on vascular and renal regional hemodynamics in Sprague Dawley rats.

The bark of the African tree Pausinystalia yohimbe has been used as a food additive with aphrodisiac and penile erection enhancing properties. The effect of an aqueous extract of P. yohimbe (CCD-X) on renal circulation was assessed in order to test the hypothesis that it possesses additional effects on nitric oxide production and/or endothelin-1 (ET-1)-like actions. In vivo studies with CCD-X in Sprague Dawley rats demonstrated a dose-dependent (1-1000 ng/kg) increase in mean blood pressure (p < 0.001) and an increase in medullary blood flow (MBF) (p < 0.001). Both the pressor action and renal medullary vasodilation were blocked by endothelinA (ETA) receptor antagonist BMS182874 and endothelinB (ETB) receptor antagonist BQ788 in combination. L-Nomega-nitro-l-arginine methyl ester (L-NAME; 10 mg/kg) also inhibited the increase in MBF induced by CCD-X. In vitro studies in isolated perfused kidney and in pressurized renal microvessels confirmed the dose-dependent vasoconstrictor action of this extract. ETA receptor antagonist BQ610 and ETB receptor antagonist BQ788 separately and significantly attenuated the renal vasoconstrictor actions of the extract (p < 0.001 ANOVA). These preliminary observations indicate that, in addition to the alpha-adrenergic antagonist actions that characterize yohimbine, CCD-X possesses endothelin-like actions and affects nitric oxide (NO) production in renal circulation. These findings suggest a strong possibility of post-receptor cross-talk between alpha2-adrenoceptors and endothelin, as well as a direct effect of alpha2-adrenoceptors on renal NO production.

Animals↗
PubMed2001

The effects of enalapril-digoxin-diuretic combination therapy on nutritional and anthropometric indices in chronic congestive heart failure: preliminary findings in cardiac cachexia.

BACKGROUND: Body wasting is a clinical feature of a variety of chronic illnesses including congestive heart failure. The wasting associated with chronic congestive heart failure (cardiac cachexia) has recently been shown to portend a worse prognosis, and it is an independent predictor of mortality. The mechanisms underlying cardiac cachexia are multi-factorial, including metabolic, nutritional, neuroendocrine and immunological aberrations. There is, however, no direct evidence that current medical treatment reverses cachexia in chronic heart failure. METHODS: The effect of enalapril, digoxin and frusemide combination on clinical, biochemical and anthropometric indices were determined in eight cachectic Nigerians with chronic congestive heart failure [body mass index (BMI) 20.80+/-2.7 kg/m(2), left ventricular ejection fraction 29+/-4% and LV mass index 161+37 g/m(2)] at baseline, and again after 3 and 6 months of therapy. Ten age- and sex-matched healthy volunteers whose anthropometric data were concurrently measured served as controls. RESULTS: The anthropometric and clinical measurements were significantly (P<0.001) reduced in heart failure compared to the healthy controls. Congestive hepatomegaly significantly regressed from 161+/-20 mm to 123+/-13 mm after 6 months therapy (P<0.001 ANOVA). There was a significant increase in the sum of four skin fold thickness from 27.6+/-3.3 mm to 30.1+/-3.9 mm at 6 months (P<0.001 ANOVA) 95% confidence intervals for the difference being 1.42 to 3.4 mm. There was a significant increase in the mid-upper arm circumference (P<0.001 ANOVA) with a 95% confidence interval of 0.87-2.1 cm, and a similar trend for increased mid-thigh circumference (95% confidence limits 0.93-5.30 cm) was apparent. Plasma albumin and sodium increased significantly (P<0.05) from 30.1+/-3.8 g/l and 136+/-5.9 mmol/l to 32.9+/-2.5 g/l and 139+/-3.9 mmol/l, respectively. There was a positive and significant correlation between the treatment induced increases in plasma albumin and the increase in mid-upper arm circumference (y=0.25x+0.8, r=0.76, P=0.03 ANOVA) but not with the change in skin fold thickness. CONCLUSION: The preliminary results demonstrate increased subcutaneous fat (increased skin fold thickness), greater muscle bulk (increased mid-upper arm and thigh circumferences) together with a significant elevation in plasma albumin and the hematocrit, which reflect the anabolic state in patients treated with ACE inhibitor-digoxin-diuretic with congestive heart failure.

Adult↗
PubMed2001

Cardiac autonomic function in Blacks with congestive heart failure: vagomimetic action, alteration in sympathovagal balance, and the effect of ACE inhibition on central and peripheral vagal tone.

Cardiac autonomic dysfunction is common in heart disease with or without congestive heart failure, and can cause sudden cardiac death. However, cardiac autonomic abnormalities in non-ischemic (hypertensive) heart failure, which is prevalent in Black Africans is poorly documented. We conducted a cross-sectional study of 32 patients with congestive heart failure, mostly secondary to hypertension (aged 52 +/- 15 years, with ejection fraction of 0.38 +/- 11) and 30 age- and sex-matched healthy volunteers (aged 51 +/- 11 years, 14 males/16 females). Cardiac autonomic function was assessed by the Valsalva's maneuver, respiratory sinus arrhythmia (for cardiac vagal tone) and the pressor and chronotropic changes following forearm isometric handgrip exercise and the assumption of upright posture (tests of sympathetic function). The exercise tolerance of the cardiac patients was assessed by the distance covered during 6 min of walking. The Valsalva ratio was significantly lower in chronic heart failure, 1.10 +/- 0.08 compared to the healthy controls 1.47 +/- 0.20 (p<0.001). Specifically, the phase IV bradycardia in heart failure, was significantly attenuated to 650 +/- 121 msec compared to the value of 935 +/- 101 msec in healthy controls (p<0.001). The phase 11 Valsalva tachycardia did not differ between the patients and controls. The respiratory sinus arrhythmia was also significantly reduced in chronic heart failure (p<0.05) compared to controls. Treatment of the heart failure patients with enalapril-digoxin and diuretics by 4 weeks, resulted in a reversal of the autonomic abnormalities. The phase IV bradycardia increased significantly to 798 +/- 164 msec (p<0.01) and the Valsalva ratio to 1.35 +/- 0.25 (p<0.01) and the respiratory sinus arrhythmia increased toward normal. There was close positive correlation between the Valsalva's ratio and the 6 min self paced distance covered (r = 0.44, p = 0.03 ANOVA), and a weak inverse correlation to cardiac size and cardiothoracic ratio (r = -0.31, p = 0.09). This study demonstrates cardiac autonomic dysfunction (especially reduced vagal tone) in Black Nigerians with mainly non-ischemic congestive heart failure. The parasympathetic dysfunction significantly correlates with severity of heart failure. Current treatment reverses autonomic dysfunction to values seen in healthy age matched controls, mainly through augmentation of cardiac parasympathetic activity.

Adult↗
PubMed2000

Mechanisms of chloroquine-induced body-scratching behavior in rats: evidence of involvement of endogenous opioid peptides.

Chloroquine is commonly used in the chemotherapy of malaria fever, and as an antiinflammatory disease-modifying agent in patients with rheumatoid arthritis or systemic lupus erythematosus. Administration of chloroquine (20.0 mg/kg IP) significantly (p < 0.05) increased the frequency of body scratching in rats to 29.5+/-9 in 30 min, compared to saline control animals (6.5+/-2/30 min). Morphine, a mu-opiate receptor agonist (1.0 mg/kg IP), potentiated the chloroquine-induced rat body scratching to 40+/-6.6, while the mu-opiate receptor antagonist, naltrexone (0.25 mg/kg, IP, given 15 min prior) blocked the chloroquine induced body scratching to 4.5+/-2 (p < 0.05 ANOVA). In addition, the frequency of chloroquine (20.0 mg/kg IP)-induced body scratching was significantly reduced to 9.1+/-3 in 30 min in rats rendered tolerant to morphine (p < 0.05 ANOVA) compared to the scratching frequency of 40+/-6.6 in morphine-naive rats. These suggests an involvement of mu-opioid receptors and/or endogenous opioid peptides in chloroquine induced body scratching in rats. Promethazine, a histamine-receptor antagonist (1.0 mg/kg IP, given 15 min prior to chloroquine) and the corticosteroid, dexamethasone (1.0 mg/kg, IP, given 15 min prior) separately and significantly (p < 0.01) inhibited the chloroquine-induced scratching in rats, in a similar manner to clinical studies in malaria. Collectively, the novel results implicate opioidergic mechanisms, and confirm the efficacy of antihistamine and corticosteroids in chloroquine body scratching in rats. It also strongly suggests that the chloroquine-induced body-scratching behavior in the rat may be a useful experimental model for chloroquine-induced pruritus in humans.

Animals↗
PubMed2000

Creatinine clearance estimation from serum creatinine values: evaluation and comparison of five prediction formulae in Nigerian patients.

Predictability of creatinine clearance (CrCl) from serum creatinine would reduce the cost of renal care and obviate the need for 24-hours urine collection. Correlations have been established between serum creatinine (Scr) and 24-hour urinary creatinine clearance with derivation of various formulae. We have tested the applicability of these formulae in 34 Nigerian patients (22 males, 12 females) aged 18 to 58 years, (mean age 34.97 +/- 11.20 years) with established chronic renal failure (CRF) mean Scr level 742.26 +/- 388.15 mol/L. 32 age and sex matched healthy adults with serum creatinine values below 120 umol/l., served as controls. Serum creatinine and 24 hour CrCl levels were determined on two consecutive occasions. Creatinine clearance values were also derived from Scr using each of the established prediction formulae: Cockcrof and Gault [1] Gates [2] Hull et al [3]; Jelliffe [4]; and Mawer et al [5]. A relationship was sought between measured CrCl and the predicted values (derived) using the stated formulae. Regression equation were generated and correlation coefficient r, coefficient of determination r2, F-ration, prediction error, all defining the nature and strength of relationship were determined. We observed that good and statistically significant correlations exist between measured CrCl values and those predicated from the formulae (r ranging from 0.908 to 0.968 and r20.82 to 0.93 P = 0.000) and that a linear relationship exists in all cases. Cockcroft and Gault formula gave the highest coefficient of determination r2 = 0.94. It is concluded that the existing formulae are adequate for determining CrCl from Scr and should be frequently used in the long term follow-up of patients with Chronic Renal Failure (CRF) in our setting.

Adolescent↗
PubMed1999

Anthropometric evaluation of cachexia in chronic congestive heart failure: the role of tricuspid regurgitation.

Cardiac cachexia has recently been identified as an independent risk factor for mortality in chronic congestive heart failure. The aims of our study were to further identify the clinical or biochemical predictors or correlates of the cachexia, and to quantitate the magnitude of wasting. We undertook an anthropometric comparison of 30 patients with congestive heart failure, aged 56 (13) years, with ten age- and sex-matched healthy volunteers and 16 patients with essential hypertension. In comparison to the healthy volunteers, the heart failure patients exhibited a trend towards a lower body mass index, 21 (2.7) versus 23 (3.8) kg/m2, the 95% confidence interval for the difference being -0.54 to 5.4. However, the mid-upper arm circumference, of 24 (3.8) cm in the heart failure patients, was significantly (P<0.02) lower than the 27 (2.0) cm in the healthy volunteer group, with a 95% confidence interval for the difference being 1.18 to 4.82 cm. The triceps, mid-thigh, scapula and abdominal skinfold thicknesses were separately and significantly (P<0.05) diminished in the heart failure patients compared to the healthy controls. The sum of the four skin fold thicknesses, with a value of 68 (13) mm in the healthy volunteers, was highly significantly greater (P<0.001) than the value of 35.6 (9) mm in the heart failure patients. The 95% confidence interval for this difference was 22.7 to 41.3 mm. The patients with essential hypertension differed significantly from the heart failure patients in all of these parameters (P<0.01), but were not statistically different from the healthy controls in the anthropometric parameters. Among the heart failure patients, those with tricuspid regurgitation (n = 12) had a worse clinical, biochemical and cachexia profile compared to patients without the tricuspid regurgitation (n = 18). The values (tricuspid regurgitation versus no regurgitation) were New York Heart Association Class, 3.5 (0.65) versus 2.7 (0.75), P<0.01; ejection fraction of 34 (9) versus 43 (13)%, not significant; greater hepatomegaly of 159 (31) versus 135 (29) mm, P<0.05; more severe hypoalbuminemia, 24.5 (2.7) versus 28.5 (6.8) g/l, P<0.05; and worse hyponatremia, 128 (4) versus 133 (5) mmol/l, P<0.05. The tricuspid regurgitation group had a significantly more severe reduction in abdominal and scapula skin fold thickness (P<0.01) than that found in patients without tricuspid regurgitation. The sum of the four skin fold thicknesses was significantly lower (P<0.05) in tricuspid regurgitation, 30.9 (8) mm, than in heart failure without associated regurgitation, 38.0 (9.6). The 95% confidence interval for the difference was 0.8 to 13.4 mm. It is concluded that significant diminution of muscle bulk and subcutaneous fat occurs in chronic heart failure. Tricuspid regurgitation may be an accentuating and accelerating risk factor for cardiac cachexia, on account of a greater hypoalbuminemia and hyponatremia, which, presumably, results from the associated protein-losing enteropathy.

Anthropometry↗
PubMed1999

The lack of efficacy of topical beta-blockers, timolol and betaxolol on intraocular pressure in Nigerian healthy volunteers.

PURPOSE: The beta-adrenoceptor antagonists are commonly used drugs in ophthalmic and medical practice. While beta-blockers may show reduced antihypertensive efficacy in African patients, the effect of beta-blockers on intraocular pressure (IOP) in African healthy volunteers is less well known. METHODS: This single-masked, placebo-controlled, randomised study was conducted to investigate the response of healthy Nigerian volunteers to a single drop of the beta-adrenoceptor antagonists timolol and betaxolol. Twenty-five volunteers participated in the study; however, only 19 were able to complete the study. The concentrations of the beta-blocker used were 0.0625%, 0.125%, 0.25% and 0.5%. One eye of the volunteers was used while the other eye served as control. The baseline IOP was documented and IOP measured hourly over 6 h. Pupillary size, corneal sensitivity and visual acuity were also assessed. Cardiovascular parameters were also documented hourly (blood pressure, heart rate, pulse rate). RESULTS: Only 0.5% concentrations of both beta-adrenoceptor antagonists caused any significant IOP reduction in normal volunteers (p < 0.05). The maximal falls were -2.33 +/- 2.2 mmHg and -1.23 +/- 0.6 mmHg with timolol and betaxolol, respectively. The IOP reduction produced lasted for only 4 h, after which the IOP returned to baseline. There was also an overshoot of the IOP above the baseline values in all the volunteers (+2.0 to +2.3 mmHg). There was no significant change in the cardiovascular parameters. There was no effect on the pupillary size, visual acuity or corneal sensitivity. There was no significant change in IOP and cardiovascular parameters in the placebo group. CONCLUSIONS: Both beta-adrenoceptor antagonists caused an attenuated IOP reduction in African normal volunteers, compared with values reported in Caucasians. There was a rebound intraocular hypertensive effect demonstrated with both beta-adrenergic antagonists in blacks.

Administration, Topical↗
PubMed1998

Vasodilator therapy of hypertensive acute left ventricular failure: comparison of captopril-prazosin with hydralazine-isosorbide dinitrate.

A prospective study to evaluate and compare the cardiorespiratory effects and clinical efficacy of the Neurohormonal inhibitors (Captopril 50 mg+prazosin 1 mg only) and direct arteriolar and venular dilators (Intravenous hydralazine 30 mg+oral isosorbide dinitrate 30 mg) used as vasodilator therapy, was undertaken in a randomized, single blind study in 17 Nigerian patients with hypertensive acute left ventricular failure. Both vasodilator regimes separately and significantly reduced the systolic and diastolic blood pressures (P<0.001 ANOVA), heart rate (P<0.001 ANOVA), and the respiratory rate (P<0.05 ANOVA), the double product, but increased the peak expiratory flow rate (P<0.05 ANOVA). However, the neurohormonal antagonists, captopril and prazosin (n=9) caused a statistically significantly greater reduction in heart rate (P<0.05 ANOVA) respiratory rate (P<0.05 ANOVA) and induced a significantly greater increase in the self-paced exercise capacity, 24 h after initiation of treatment, (P<0.02) compared to the hydralazine and isosorbide dinitrate combination (n=8). Five of the nine patients on the neurohormonal antagonist therapy were ambulant at 24 h, compared to none of the eight patients receiving conventional venular and arteriolar dilators hydralazine and isosorbide dinitrate (chi2=5.84 dfi P<0.05). There was a significant inverse correlation between the systolic blood pressure heart rate product, and the distance covered during symptom limited self paced exercise capacity (r=-0.58, P=0.0146 ANOVA). One of eight patients in the hydralazine+isosorbide nitrate combination died, but there was no mortality in the captopril+prazosin group. These findings collectively suggest that captopril+prazosin combination may be a superior vasodilator therapy compared to hydralazine-isosorbide dinitrate, in hypertensive acute pulmonary oedema.

Adult↗
PubMed1998

Sudden unexpected death from cardiac causes in Nigerians: a review of 50 autopsied cases.

Fifty cases of sudden and unexpected death from cardiac causes in individuals between the ages of 28 and 80 years are reviewed; the causes and circumstances of the deaths of these individuals are defined. 70% were males and 44% of the deaths occurred in the 41-50 years age group. Death was due to hypertensive heart disease in 82% of the cases and only 18% were previously diagnosed. Acute left ventricular failure was the commonest (68%) cause of death. Only 4% of the total died of acute myocardial infarction from coronary artery disease. The causes of sudden cardiac death in a developing country such as Nigeria, appears to be different to the pattern in Western countries.

Adult↗
PubMed1998

Knowledge, attitude and practice of prednisolone prevention of chloroquine induced pruritus among Nigerian health workers.

Severe generalized pruritus is a common drawback in chloroquine therapy of malaria in black Africans. In a cross-sectional study, we evaluated the knowledge, attitude and practice of 117 Nigerian hospital workers, who historically itch to chloroquine, to the use of prednisolone to prevent chloroquine pruritus in malaria. Ninety per cent of respondents had a positive family history of chloroquine induced pruritus. Seventy-five per cent (92) of the subjects were aware of the anti-pruritic action of prednisolone, but only 43% (n = 40) have ever used it during malaria. Among the prednisolone users (n = 40), 25 (62.5%) had total prevention, 25% (n = 10) had marked pruritus attenuation, but no effect was seen in 12.5% (n = 5). The modal prednisolone dose causing inhibition of itching was 10 mg orally given once. Concurrent prednisolone increased compliance with chloroquine in 68% of all who used the combination, and there was no evidence of malaria recurrence.

Adult↗
PubMed1997

Chloroquine-induced pruritus in malaria fever: contribution of malaria parasitaemia and the effects of prednisolone, niacin, and their combination, compared with antihistamine.

AIMS: Chloroquine treatment of malaria fever, results in a generalized pruritus of unknown mechanism in up to 60% of adult Africans, by contrast pruritus is unusual in Caucasians following chloroquine use. METHODS: We conducted a double-blind, randomized, parallel group study to examine and compare the antipruritic effects of promethazine, niacin, prednisolone and their combination on pruritus induced by chloroquine, in 28 historical itching patients with parasitologically proven malaria fever. We also evaluated the role of the antecedent malaria parasite density in the severity of chloroquine pruritus intensity. RESULTS: The concurrent administration of chloroquine (2.1 g base total dose) with prednisolone caused a statistically significant reduction in the pruritus AUC (0, 72 h) (P < 0.001 ANOVA) compared with the antihistamine promethazine alone. The areas under the pruritus intensity-time curve were promethazine 105 +/- 28 (units h), niacin 76 +/- 22, prednisolone 28 +/- 24, and prednisolone and niacin 34 +/- 17 (P < 0.001 ANOVA). The 95% confidence interval for the difference in the pruritus AUC between prednisolone and promethazine was 8.4 to 145.6 units h. There was a statistically significant and positive correlation between the pruritus intensity (AUC 0, 72 h) and the malaria parasite load in the itching subjects, not receiving prednisolone (n = 9) (r = 0.73, P = 0.026 ANOVA). CONCLUSION: A single oral dose of prednisolone (10 mg) may be preferable to the antihistamine promethazine (25 mg) as an antipruritic agent for concurrent prescription with chloroquine in individuals predisposed to severe itching. Malaria parasite clearance and clinical amelioration were unaffected by any of the treatments.

Adult↗
PubMed1996

Concurrent alpha 1 adrenergic blockade and angiotensin converting enzyme inhibition in the treatment of congestive heart failure.

We tested the hypothesis that concurrent inhibition of the renin angiotensin system by enalapril (5 mg) and the sympathetic nervous system by alpha 1 adrenergic blockade (prazosin 1 mg) will be superior to enalapril alone in 17 patients with heart failure on standard therapy, in a single blind, placebo-controlled, randomized parallel group study for 4 weeks. Enalapril alone induced a significant increase in exercise time from 499 +/- 412 s to 707 +/- 608 s (P < 0.05, ANOVA), but the increase induced by the enalapril + prazosin combination was significantly greater (P < 0.025, MANOVA) from 214 +/- 271 to 1007 +/- 784 s as was the increase in creatinine clearance (P < 0.05).

Administration, Oral↗