Biomedical subjects

A K Manatunga

Publications and source records attributed to A K Manatunga.

27 records · Page 2Linked to original sources

PubMed1993

Longitudinal assessment of blood pressures in black and white children.

The prevalence of hypertension is greater for blacks than whites. Whether black children have higher blood pressure than white children is less clear. We investigated this issue through a prospective longitudinal assessment of blood pressure in 345 white children and 164 black children. Each child had his or her blood pressure measured every 6 months for 2 to 5.5 years. The means for systolic and diastolic blood pressures for each individual were calculated, and the rate of change in blood pressure over time for each subject was estimated. The mean blood pressure and the mean rate were compared between gender-specific black and white groups. For both boys and girls, the mean systolic blood pressure was 2 mm Hg higher in black children than white children (P = .0008). Boys had a higher systolic blood pressure than girls (P = .0048). The mean diastolic blood pressure was 1.5 mm Hg higher in black children than in white children (P = .0270); no significant gender difference in diastolic blood pressure was observed. Age, weight, height, and body mass index were highly correlated with blood pressure. When accounting for these variables, for girls the racial difference in systolic blood pressure remained significant, whereas the difference in diastolic blood pressure in boys and girls was no longer significant. The rate of increase in blood pressure over time was significantly greater in blacks than whites: for systolic blood pressure, P = .0002, and for diastolic blood pressure, P = .009.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1993

Medication compliance in elderly outpatients using twice-daily dosing and unit-of-use packaging.

OBJECTIVE: To determine the effect of unit-of-use drug packaging of medications on compliance among elderly outpatients treated with complex medication regimens. DESIGN: Nonblind, randomized, clinical trial. SETTING: Geriatric outreach health centers in urban public housing units for independent-living elderly people. PATIENTS: Thirty-one patients (aged > or = 60 y), each taking three or more prescribed medications. Patients were randomly assigned to one of three study groups: group 1 (n = 12), no change in dosing or packaging; group 2 (n = 10), conventional packaging with twice-daily dosing; group 3 (n = 9), unit-of-use packaging with twice-daily dosing. INTERVENTION: A unit-of-use package consisting of a two-ounce plastic cup with a snap-on lid containing all medications to be taken at the time of dosing. MAIN OUTCOME MEASURES: Medication compliance was assessed monthly for six months using tablet counts. RESULTS: Medication compliance was significantly better in group 3 (92.6 percent) using unit-of-use packaging compared with either group 1 (79 percent) or group 2 (82.6 percent) (p = 0.017). Compliance did not differ between groups 1 and 2. CONCLUSIONS: In this small study of elderly outpatients taking three or more medications, unit-of-use packaging and twice-daily dosing improved medication compliance compared with conventional packaging.

Activities of Daily Living↗

PubMed1993

Racial differences in aldosterone excretion: a longitudinal study in children.

Aldosterone production, estimated from urinary excretion of aldosterone and the plasma aldosterone level, was found in a previous cross-sectional study to be lower in black children than white children. The present study examined aldosterone excretion longitudinally to determine whether the aldosterone excretion rate changed with time and if the racial difference in aldosterone excretion persisted. Urine samples were collected every 6 months for up to 5.5 yr in 351 white and 170 black children for measurements of aldosterone, sodium (Na+), and potassium (K+) excretion. Results were expressed per mumol urinary creatinine. Mean values for excretion rates for the total longitudinal period were determined. Na+ excretion was not significantly different in the two groups, whereas K+ excretion was 18% lower in blacks than whites (P = 0.0001). Body weight and urinary Na+ and K+ excretion were significantly related to aldosterone excretion. After adjusting for these variables, the aldosterone excretion rate was 35% lower in blacks than whites (P = 0.0001), a racial difference that did not change with age. Aldosterone excretion rates showed no longitudinal trend to either increase or decrease. The physiological relevance of the lower aldosterone excretion rate in black children remains unknown.

Adolescent↗

PubMed1992

The interaction of norepinephrine excretion with blood pressure and race in children.

OBJECTIVE: The purpose of this study was to examine the relationship between urinary norepinephrine excretion and blood pressure, and to determine the influence of race on this relationship. Urinary norepinephrine was used to estimate renal and systemic sympathetic nervous system (SNS) activity. DESIGN: Fifty black and forty-nine white normotensive children aged 9-14 years had their blood pressure measured, and provided an overnight urine sample. METHODS: Urinary norepinephrine was measured by radioenzymatic assay. Excretion rates of norepinephrine were expressed per milligram urinary creatinine. RESULTS: Black children had age-adjusted mean diastolic and systolic blood pressure which was higher than in white children. For both blacks and whites, nocturnal urinary norepinephrine excretion rates were positively related to age-adjusted mean diastolic blood pressure, but not to systolic blood pressure. Norepinephrine excretion was significantly lower in black children compared with white children. CONCLUSION: These findings suggest that the higher blood pressures in black children were not causally related to greater SNS activity. The SNS may have been suppressed in black children, possibly by a greater expansion of plasma volume, alternatively, black children may have been more sensitive to the influences of the SNS than white children.

Adolescent↗

PubMed1992

Effects of flurbiprofen on renal function in patients with moderate renal insufficiency.

1. Renal function was assessed in eight patients with chronic renal insufficiency following the administration of flurbiprofen 50 mg as a single dose and after chronic administration of 50 mg four times daily for 8 and 27 days. Diet and fluid intake were controlled. 2. Inulin and creatinine clearances and urinary excretion of sodium were measured at baseline and every 20 min for at least 3 h after dosing. The time of the mean peak concentration of (S)-flurbiprofen was used to guide the analysis of the clearances. Creatinine clearance, urinary excretion of sodium, and serum sodium and potassium were also assessed for 24 h after the dose and on a daily basis. Body weight and blood pressure were measured on a daily basis. 3. Decrements in inulin and creatinine clearances were small and reversible within 3 h of an oral dose of flurbiprofen. Comparison of baseline clearances for the three study periods (first dose and at 8 and 27 days of chronic dosing) revealed a lack of chronic effect on glomerular filtration rate. 4. In contrast, flurbiprofen caused a substantial (73 to 86%) and progressive decrease in the urinary excretion of sodium that reached a nadir within 4-5 h after drug administration. However, comparison of baseline values did not differ, indicating that balance conditions had been re-established. 5. Results of 24 h assessments were in agreement with the clearance study results. Reduced urinary excretion of sodium appeared to be limited to the first few days of flurbiprofen administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Genetic influences on the urinary excretion of aldosterone in children.

Several studies have shown an inverse relation between blood pressure and plasma aldosterone levels. Since blood pressure is in part genetically regulated, we looked for evidence that genetic factors might also affect aldosterone production. The nocturnal urinary excretion rate was used to estimate aldosterone production, and electrolyte excretion rates were used to estimate sodium and potassium intakes. Studies were carried out in monozygotic (MZ) (n = 37 pairs) and dizygotic (DZ) (n = 26 pairs) twins, aged 6-17 years. Both groups of twins were white. The intraclass correlation coefficient for aldosterone excretion was 0.686 (p = 0.0001) for MZ twins, and 0.290 (p = 0.079) for DZ twins, indicating high heritability for the aldosterone excretion rate. In a second study, we looked for a racial effect on the genetic regulation of aldosterone excretion. Siblings from both black and white families (72 black siblings and 157 white siblings) were selected from an ongoing longitudinal study. Mean values for nocturnal aldosterone excretion, rates measured every 6 months over 1.5-3.5 years, were used in the analysis. The intraclass correlation coefficient for aldosterone excretion, adjusted for sodium and potassium excretion, was 0.510 (p = 0.001) for black siblings and 0.087 (p = 0.228) for white siblings, indicating a strong familial aggregation for aldosterone excretion in black children. In conclusion, studies in twins showed that regulation of urinary aldosterone excretion in children is determined partially by genetic factors. A familial component affecting the aldosterone excretion rate appears to be much stronger in blacks than in whites.

Aldosterone↗

PubMed1990

Adrenal androgen excretion during adrenarche. Relation to race and blood pressure.

We have previously shown that black children have higher blood pressures than white children. In the present study, we examined whether a possible racial difference in adrenal androgen production during adrenarche might contribute to the racial disparity in blood pressure. Adrenal androgen production was estimated from urinary excretion of adrenal androgen metabolites that showed cross-reactivity with antisera to dehydroepiandrosterone sulfate (DHEA-S). Urine samples were collected overnight in 798 children, one third of whom were black. Analyses were performed for two different age groups, less than 10 years and 10 years or more of age. In children less than 10 years of age, adrenal androgen excretion rates were 17% higher in blacks than in whites (p = 0.0099); adrenal androgen excretion rates tended to be higher in older black children as well, but differences here were not statistically significant. Adrenal androgen excretion rates were positively correlated with diastolic blood pressure in the older age group only (p = 0.014). However, when the relation of race to blood pressure was examined along with adrenal androgen excretion adjusted for age, sex, and weight, race remained an independent contributor to the level of blood pressure, suggesting that a difference in adrenal androgens could not explain the racial differences in blood pressure. In summary, black children produced more adrenal androgen, but this did not explain their higher blood pressures. In older children, where adrenal androgen excretion rates were higher, diastolic blood pressure and adrenal androgen excretion were positively related, suggesting that adrenal androgens participate in establishing the level of blood pressure in young people.

Adrenal Glands↗

PubMedDate not supplied

Modelling survival data with a cured fraction using frailty models.

Cure models have historically been utilized to analyse time-to-event data with a cured fraction. We consider the use of frailty models as an alternative approach to modelling such data. An attractive feature of the models is the allowance for heterogeneity in risk among those individuals experiencing the event of interest in addition to the incorporation of a cured component. Utilizing maximum likelihood techniques, we fit models to data concerning the recurrence of leukaemia among patients receiving autologous transplantation treatment. The analysis suggests that the gamma frailty mixture model and the compound Poisson improve on the fit of the leukaemia data as compared to the standard cure model.

Humans↗

PubMedDate not supplied

Prospective comparison of peritoneoscopic and surgical implantation of CAPD catheters.

Prospectively collected data were analyzed comparing surgically and peritoneoscopically placed peritoneal dialysis catheters in 88 patients. Peritoneoscopically placed catheters were found to survive longer than surgically placed ones. Rates of exit site infection and pericatheter leaks were found to be similar with both techniques.

Adult↗