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Biomedical subjects

N W Solomons

Publications and source records attributed to N W Solomons.

At least 19 recordsLinked to original sources
PubMed1992

Studies on the application of the relative-dose-response test for assessing vitamin A status in older adults.

We investigated the time course and the reproducibility of the relative-dose-response (RDR) test for assessing vitamin A status in older adults. The maximum plasma retinol response to 480 retinol equivalents (RE) of retinyl palmitate in abnormal responses was at 6 or 7 h after dosing compared with the 5-h sampling interval recommended by others for younger adults and children. With respect to reproducibility, the diagnostic concordance of two RDR tests at 7-d intervals in 14 elders was 71%. In 29% of tests, one test was abnormal and the other normal. Linear regression of the two RDR values in these 14 subjects gave a correlation coefficient of -0.08. We conclude that the procedure for the RDR should be modified when applied to persons greater than 60 y of age, and that multiple repetitions of the test are needed to provide a stable indication of vitamin A stores in an elderly individual.

Aged↗
PubMed1992

Nutrition and aging: potentials and problems for research in developing countries.

The demographic explosion of persons over 60 years of age is a reality in developed and developing countries alike. There is evidence that research on aging and nutrition in Third World countries is growing and developing. Specific research programs, and the linking of these programs in timely multicenter efforts, promise both valuable descriptive research for the benefit of national populations and comparative insights that will help us to learn more, collectively, about the intrinsic nature of the aging process itself.

Aged↗
PubMed1992

[Colonic fermentation in humans: effect of the ingestion of meat associated to milk].

The amount of breath H2 produced for 6 h following the ingestion of 240 ml of milk was used as an index of the rate of colonic fermentation of undigested lactose in 8 lactase non-persistent Guatemalan adults. Treatments in separate days included milk alone, milk with 400 g cooked beef, lactose pre-hydrolyzed milk with the same amount of beef, beef alone and fasting for 6 h. Excess excretion of H2, calculated as the mean area under the curve were 178 +/- 31 ppm h with milk alone, 50 +/- 17 with milk plus beef, -1 +/- 26 with prehydrolyzed milk (p > 0.001). Peak increments of breath H2 followed the same trend: all 8 subjects over 20 ppm with milk alone, 2 with milk plus beef and none with hydrolyzed milk, beef alone or fasting. Thus, cooked beef significantly reduces the rate of appearance of intact lactose in the large bowel of lactase deficient adults.

Adult↗
PubMed1992

Mouth-to-anus transit-time predicts the severity of fecal water loss in acute dehydrating diarrhea.

The mouth-to-anus transit time was estimated in 24 young children admitted to an outpatient rehydration unit with acute dehydrating diarrheal disease by adding an oral fecal marker (brilliant blue) to the first draught of oral rehydration solution. Transit times ranged from 30 to 242 min. There was a highly significant (logarithmic) relationship between rate of fecal output and transit time (r = 0.74; p < 0.001). Three of 24 subjects could not be rehydrated orally, were declared treatment failures, and were hospitalized for intravenous therapy. All of them had had an initial transit time of less than 50 min, and constituted three of the four subjects with this rapid rate of transit. Thus, a rapid mouth-to-anus transit time had a 100% sensitivity to predict treatment failures and a 75% predictive accuracy for a "positive" test. Although our series is small, the findings suggest that fecal markers may be useful in remote areas to assist in the early detection of diarrheal episodes that cannot be managed by oral rehydration therapy.

Acute Disease↗
PubMed1992

Lactose digestion from unmodified, low-fat and lactose-hydrolyzed yogurt in adult lactose-maldigesters.

The efficiency of carbohydrate absorption from two unmodified plain yogurts, a low-fat yogurt and a yogurt produced from lactose-hydrolyzed milk, was compared using the breath hydrogen response in 14 lactose-maldigesters. The maldigesters showed symptoms of intolerance to a standard 360 ml glass of milk containing 18 g lactose. Compared to intact milk, the breath hydrogen response to two varieties of unmodified yogurt and the lactose hydrolyzed yogurt was severely attenuated while the hydrogen response to low-fat yogurt was intermediate. Intolerance symptoms were significantly and equally reduced with all four yogurt products compared to milk. Ten lactose-digesters had a significantly greater efficiency of lactose digestion with 360 ml of milk than the 14 maldigesters; however, except for the magnitude of the maximum rise in breath H2, no inter-group differences were observed in response to unmodified yogurt. We conclude that lactose prehydrolysis adds nothing to the ability to tolerate and digest plain, full-fat yogurts, but it may be useful with low-fat or pasteurized varieties.

Adult↗
PubMed1991

Plasma response to oral beta-carotene in Guatemalan schoolchildren.

The response to oral doses of beta-carotene (0 mg, n = 10; 15 mg, n = 20; and 30 mg, n = 21) was studied in 51 Guatemalan children aged 8-15 y, with mean fasting plasma retinol concentrations of 1.72 +/- 0.38 mumol/L. Beta-carotene was delivered with a chocolate drink containing 8.4 g fat. Serial blood sampling was performed at intervals up to 48 h. Circulating retinol concentrations remained relatively constant. The maximum increases in plasma beta-carotene after the 30- and 15-mg doses for all subjects occurred at 24 h and were 0.29 and 0.23 mumol/L, respectively. Time of maximum increase for individuals varied and average maxima over the 48-h period for individuals were 0.13 and 0.26 mumol/L for the 15- and 30-mg-treatment groups, respectively. Increased plasma beta-carotene concentrations were not predicted by recent intake of dietary vitamin A, fasting plasma concentrations, or anthropometric measurements.

Administration, Oral↗
PubMed1991

Nutritional problems of developing countries.

The nutritional problems of developing countries are conditioned by poverty, near exclusive reliance on plant sources of nutrients, and high rates of infections. Common deficiency diseases include protein-energy malnutrition, nutritional anemias, vitamin A deficiency, iodine deficiency, and possibly others. Population subgroups at particularly high risk are the children and women of poor families. Control of these nutritional diseases requires systematic diagnosis of the existing situation and appropriate intervention strategies such as targeted food and specific micronutrient supplementation, food fortification, nutrition education, and reductions in infections as well as general improvements in economic conditions and social equity.

Child↗
PubMed1990

Test-retest reproducibility of the relative dose response for vitamin A status in Guatemalan adults: issues of diagnostic sensitivity.

The relative dose response (RDR) test has been used as a functional measure of whole-body stores of vitamin A in humans. We have examined the reproducibility of the RDR procedure in a population of Guatemalan adult subjects who would be expected to show a moderate prevalence of hypovitaminosis A. Fifty-one subjects were administered a standard RDR test, and the plasma samples were analyzed for retinol, tocopherol, retinol binding protein (RBP) and prealbumin (PAL). Thirty-four of the subjects underwent repeat RDR tests 7 d later. Plasma levels in fasted subjects were as follows: retinol, 1.35 +/- 0.30 mumol/L; RBP, 37.8 +/- 7.7 mg/L; PAL, 187.0 +/- 39.0 mg/L; and tocopherol, 16.6 +/- 6.2 mumol/L. RDRs ranged from -35.2% to +63.1%, with a mean of 2.6 +/- 10.4%. Overall, we observed poor within-subject reproducibility of the RDR procedure whether expressed numerically or by diagnostic classification. Moreover, in contrast to previous studies in children, we observed fewer positive RDR tests than would be expected for the population studied. Nevertheless, the mean RDR was inversely proportional to fasting retinol levels, thus confirming the validity of the biological basis of the RDR procedure in humans. Because of high intra-individual variability with this test, investigators should be cautious when using the RDR procedure in serial studies to monitor the efficacy of therapeutic interventions or subject compliance to dietary regimens.

Administration, Oral↗
PubMed1990

Test-retest reproducibility of the relative dose response for vitamin A status in Guatemalan adults: issues of diagnostic specificity.

The relative dose response (RDR) test was examined with regard to specificity and reproducibility in subjects with adequate dietary intake and normal liver reserves of vitamin A. Twelve subjects were administered an RDR test four times over 22 d, including one placebo test in which the oral dose of vitamin A was omitted. Additionally, static measures of retinol, tocopherol, retinol binding protein (RBP) and prealbumin (PAL) were taken to determine the intra- and inter-individual coefficient of variation for these blood constituents. Intra-individual coefficients of variation were as follows: retinol, 8.8%; RBP, 11.5%; PAL, 7.6%; and alpha-tocopherol, 8.8%. The mean RDR in vitamin A-replete subjects was 1.2% and ranged from approximately -25% to 11%. No differences were observed between placebo and true RDR (i.e., with vitamin A) test responses, and there was no difference among the three true RDRs over a period of 22 d. Consistent with the hypothesis upon which the RDR test is based, nascently absorbed vitamin A evidently entered a storage pool in the liver of vitamin A-replete subjects without immediate release to peripheral sites of utilization. Because the RDR test results were normal in all subjects, the procedure appears to offer high test specificity and does not falsely diagnose hypovitaminosis A. Nevertheless, the magnitude and direction of the RDR within an individual over 22 d were highly variable, and this variability may preclude the use of a single measure of the RDR to grade the relative vitamin A nutriture of an individual subject.

Administration, Oral↗
PubMed1990

Weanling diarrhea: a case report.

This case report describes a 14-month-old Guatemalan boy suffering from diarrhea and malnutrition. He had been healthy and experienced normal growth until weaning, which began at six months of age. Introduction of semisolid foods at this time was accompanied by bouts of diarrhea and a reduced growth rate. After admission to hospital at 14 months of age, he was found to have protein-energy malnutrition of the edematous type (kwashiorkor) and to be infected with Giardia lamblia. Therapy with metronidazole and a high-protein diet resulted in satisfactory weight gain and cessation of the diarrhea.

Animals↗
PubMed1990

Mineral excretion during acute, dehydrating diarrhea treated with oral rehydration therapy.

Twenty-four male Guatemalan children, aged 7 to 23 mo, suffering dehydration due to acute diarrhea were studied to assess their fecal endogenous losses of trace minerals zinc, iron, and copper while treated with oral rehydration therapy, either with standard or glycine-added solutions. Sodium and potassium excretions (from endogenous and exogenous sources) were also monitored. No statistically significant effect of glycine was observed on any of the minerals studied, although a tendency to higher output was seen with zinc. Median rates of fecal excretion of zinc, iron, and copper were 6.08, 6.33, and 1.61 micrograms/kg/h, respectively, whereas those for sodium and potassium were 11.2 and 9.7 mg/kg/h. All of the minerals' excretion showed significant linear correlations with fecal volume, r values were 0.47 (Zn), 0.64 (Fe), 0.77 (Cu), 0.98 (Na), and 0.97 (K). Mineral-mineral interactions also were evident, with such correlations in fecal excretion rates as: Zn versus Cu, r = 0.75; Zn versus Fe, r = 0.62; Fe versus Cu, r = 0.76.

Diarrhea↗
PubMed1989

Lactase and placebo in the management of the irritable bowel syndrome: a double-blind, cross-over study.

A double-blind, cross-over, therapeutic, clinical trial of the efficacy of exogenous, microbial beta-D-galactosidase to reduce the symptoms of the irritable bowel syndrome (IBS) was conducted in 12 patients whose customary diets regularly included milk. Eight of the 12 subjects (67%) proved to be lactase-nonpersistent, lactose-maldigesters when challenged with a aqueous dose of 12.5 g. The study lasted 4 months, with the first month a non-intervention, control period and the latter 3 months alternating in the sequence, treatment/placebo/treatment, or placebo/treatment/placebo. When symptoms during trial months were analyzed by the cumulative sum procedure, gastrointestinal symptoms were found to be independent of lactase treatment. We found a positive temporal association of the severity of both gastrointestinal and non-gastrointestinal symptomatology. In populations with a high prevalence of lactose deficiency, IBS symptoms appear to be independent of lactose maldigestion.

Adult↗