PubMed Health⌕ Search

Biomedical subjects

F C Johnson

Publications and source records attributed to F C Johnson.

10 recordsLinked to original sources
PubMed1999

Endogenous prostaglandin formation in the field-stimulated guinea-pig vas deferens: comparison of the inhibitory effects of indomethacin and NS-398.

Prostaglandin (PG) E2 inhibited both phases of contraction produced by electrical field stimulation of the guinea-pig vas deferens. PGF2alpha and PGD2 were without effect on this preparation. Carbacyclin (a PGI2) analogue inhibited the first phase of contraction at higher concentrations, whereas U46619 (a thromboxane mimetic) potentiated both phases of contraction. As exogenous arachidonic acid inhibits both phases of contraction of the electrically field-stimulated guinea-pig vas deferens, it is likely that the arachidonic acid is converted to PGE2 in the vas deferens. Indomethacin, a non-specific inhibitor of prostaglandin H synthase (PGHS), attenuated the inhibitory actions of exogenous arachidonic acid when examined on the first phase of contraction. NS-398, a relatively specific inhibitor of PGHS-2, also prevented the inhibitory action of exogenous arachidonic acid. However, NS-398 was much less effective than indomethacin in this respect even though NS-398 and indomethacin inhibit PGHS-2 with similar potencies. Consequently, the findings suggest that exogenous arachidonic acid is converted to PGE2 in the guinea-pig vas deferens by the actions of PGHS-1 and, to a lesser extent, by PGHS-2.

Animals↗
PubMed1999

The impact of the AFDC and Food Stamp programs on child nutrition: empirical evidence from New Orleans.

This study tests the hypotheses that the participation in the Aid to Families with Dependent Children (AFDC) and Food Stamp programs has a positive impact on children's nutritional status, after controlling for other potentially important household- and individual-level characteristics. The analysis is based on the responses of a health facility survey of 246 pairs of low-income mothers and children in New Orleans. The results indicate that participation in the AFDC and Food Stamp programs is associated with increased anthropometric status of children, but the foods consumed by children in families receiving welfare benefits were of significantly lower nutritional value than foods consumed by other children. Among the study's conclusions are the following: (1) in this low-income setting, AFDC and Food Stamp benefits are associated with higher food expenditures, higher anthropometric levels, but inferior diets, and (2) female-headed households spend more on food expenditures than other households, after controlling for other individual- and household-level characteristics.

Adult↗
PubMed1994

Child anthropometry and mortality in Malawi: testing for effect modification by age and length of follow-up and confounding by socioeconomic factors.

As shown in a review of 28 studies, anthropometric measurements of preschool-aged children are consistently related to the risk of subsequent mortality in community-based studies from Asia and Africa (Pelletier 1994). Although the results are consistent at this general level, a number of important questions remain concerning the relationship. The purpose of this study is to address two of these questions using data from a similar study conducted in rural northern Malawi: 1) In relation to screening, are the anthropometry-mortality relationships affected by the child's age and the interval between measurement and death ("length of follow-up") and 2) In relation to policy implications, is the anthropometry-mortality relationship due to confounding by socioeconomic factors, especially when considering mild-to-moderate malnutrition. The results reveal that mortality prediction is significantly affected by child's age and length of follow-up, but the strength and direction of this effect modification varies across the four commonly used anthropometric indicators [weight-for-age (WA), height-for-age (HA), weight-for-height (WH) and arm circumference-for-age (ACA)]. An important result for public health practice is that there are no statistically significant differences in prediction across these four indicators when applied to young children (6-23 mo) and employing a 1-y follow-up period. As regards confounding, the results indicate that the anthropometry-mortality relationship is not due to confounding by socioeconomic factors when all grades of malnutrition are considered. When only mild-to-moderate malnutrition is considered, statistically controlling for confounders reduces most of the anthropometric predictors to nonsignificance (probability values to > 0.20), but the strength of the association (odds ratio) remains of the same order of magnitude. However, when effect modification by child's age and length of follow-up is taken into account, the effect of mild-to-moderate malnutrition (WA and WH) remains statistically significant for young children dying with 1 y of follow-up.

Age Factors↗
PubMed1993

Children's nutritional status in female-headed households in the Dominican Republic.

A national representative household survey of food consumption, income, and expenditure was conducted in the Dominican Republic in 1986 by Tufts University School of Nutrition in cooperation with USAID Office of Nutrition [1: Rogers B. L. and Swindale A. Determinants of Food Consumption in the Dominican Republic. USAID/S & T/Nutrition, Washington, DC, 1988]. Out of 1440 families surveyed 706 had children under 6 years of age. Anthropometric indicators of height and weight were collected for all 1251 children in the sample in a follow-up study conducted from December 1986 to January 1987 by Tufts with USAID/Santo Domingo Mission funding. Anthropometric measurements were converted to standard deviation scores using NCHS standards; nutritional status was thus measured by height-for-age (HAZ), weight-for-age (WAZ), and weight-for-height (WHZ). Earnings in families with children having males as heads-of-household were roughly one-third greater than in those with females as household head; total income was also greater in these families, though not significantly. More calories and protein per adult equivalent were available in male-headed families as well. In spite of this superior economic and dietary situation, there was a trend throughout the entire sample for children of female-headed households to be taller and heavier for their age than those of two parent homes; all three anthropometric measures showed differences in the same direction. In the lowest expenditure quartile, WAZ and WHZ were significantly greater for children in female-headed households than their counterparts in male-headed households (WAZ: P = 0.01, WHZ: P = 0.00).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

The antioxidant vitamins.

This article is an attempt to study the metabolic functions of vitamin C and E together. Such a study must necessarily be imcomplete owing to the extreme richness of the literature. The increasing importance of the work on free radical reactions, their toxicity and carcinogenic action, and also their relation to the metabolism of metals, particularly iron, copper, selenium, and zinc, shows a number of metabolic pathways with which both vitamins interact. It is hoped that this article will indicate future research possibilities.

Adolescent↗