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Biomedical subjects

C R Allen

Publications and source records attributed to C R Allen.

At least 37 records · Page 2Linked to original sources
PubMed1990

Mefloquine therapy for Plasmodium falciparum malaria in children under 5 years of age in Malawi: in vivo/in vitro efficacy and correlation of drug concentration with parasitological outcome.

The in vivo and in vitro response of Plasmodium falciparum to a single oral dose of mefloquine (25 mg/kg body weight (M25) or 15 mg/kg (M15] was studied in children under 5 years of age in Malawi. Of the children who received mefloquine, 35% vomited at least once, and 10% did not tolerate the drug because of vomiting. The therapy failure rates for the M25 group on day 7, 14, and 28 were 15%, 18%, and 42%, respectively, and these did not differ significantly from those for the M15 group (4%, 18%, and 59%). In contrast, 34 in vitro microtests (17 per group) showed schizont inhibition at less than or equal to 32 pmol mefloquine per test well. On day 7, the concentration of mefloquine in samples of blood was significantly lower in both the M25 and M15 groups for children who were parasitaemic on day 7 than in samples from those who were aparasitaemic. A positive blood smear on day 7 was strongly associated with a mefloquine concentration of less than 500 ng/ml blood on day 2 or day 7 (P less than 0.0003). Vomiting was associated with a low mefloquine concentration on day 2 but not day 7. These results suggest that mefloquine is effective against P. falciparum in Malawi but that for young children the therapy appears to be complicated by frequent vomiting.

Animals↗
PubMed1988

The spectrophotometric determination of nanomole quantities of chloride in plant tissue.

The determination of Cl- in plant tissues was investigated by FeSCN2+ spectrophotometry following SCN- displacement from Hg(SCN)2 by Cl-. The calibration curve was nonlinear, but consistent and reproducible. As little as 10 nmol Cl- could be measured. There was no obvious interference in color development by water-soluble components in plant tissues. Values obtained by this method were in close agreement with those obtained potentiometrically and by coulometric titration.

Chlorides↗
PubMed1981

Cardiovascular risk factors in Mexican Americans in Laredo, Texas. I. Prevalence of overweight and diabetes and distributions of serum lipids.

An epidemiologic survey of cardiovascular risk factors was carried out on a random sample of Mexican Americans living in two low income census tracts in Laredo, Texas. The prevalence of overweight was found to be intermediate between US national estimates and the rates recorded for Pima Indians. Similarly, the prevalence of fasting hyperglycemia was intermediate between the rates observed in a sample or predominantly Caucasian individuals and those observed in Pima Indians. Excess hyperglycemia in the Laredo Mexican American population compared to predominantly Caucasian populations does not appear to be due to a lower level of medical control of diabetes in the former. Rather, it probably reflects a true excess in the prevalence of diabetes. Serum cholesterol and triglyceride concentrations were also higher in Laredo Mexican Americans than in a Caucasian comparison population. Mexican Americans are of mixed European and native American ancestry. Native Americans have high rates of diabetes which could be on a genetic basis. The intermediate rates of hyperglycemia in Mexican Americans could thus have a genetic explanation. On the other hand, sociocultural determinants could be important since these are known to influence obesity which is a major precursor of diabetes.

Adult↗
PubMed1981

Cardiovascular risk factors in Mexican Americans in Laredo, Texas. II. Prevalence and control of hypertension.

In recent years there has been a marked improvement in the level of hypertension control nationally in both blacks and whites. Information is still lacking, however, on the level of hypertension control in Mexican Americans. The authors carried out a cardiovascular risk factor survey on a random sample of Mexican Americans living in two low income census tracts in Laredo, Texas. The percentages of hypertensive women who had been previously diagnosed, were under treatment, and were "under control" compared favorably with national figures for blacks and whites. Corresponding percentages for men indicated that their level of diagnosis, treatment and "control" still lagged behind the national figures. The prevalence of hypertension in Laredo Project participants was intermediate between those observed in national studies for blacks and whites. This finding did not clearly emerge when comparisons were based on either blood pressure distributions or prevalence of elevated diastolic pressures. These results indicate that, because of the increasing number of "controlled" hypertensives in the population, comparisons between populations and across time can no longer be based exclusively on blood pressure measurements, but must include cases of "controlled" hypertension.

Adult↗