Search PubMed⌕ Search

Biomedical subjects

N W Solomons

Publications and source records attributed to N W Solomons.

At least 127 records · Page 7Linked to original sources
PubMed1985

Rehabilitating the severely malnourished infant and child.

The failure of public health measures to control protein-energy malnutrition means that continued therapeutic, curative programs for the rehabilitation of severely malnourished infants and children will be needed for the foreseeable future. Successful rehabilitation requires an understanding of the biology of malnutrition and of the dietary guidelines for provision of appropriate formulas. It is important to recognize that protein-energy malnutrition represents a metabolically and physiologically adapted state but that full recuperation entails compensatory weight gain for recovery of the expected weight for height and body composition. Overzealous early feeding is to be avoided; protein- and energy-rich diets must be introduced gradually and sustained to provide the nutrients necessary for rapid catch-up growth. Therapy involves a three-stage process of addressing acute problems, restoring nutrient balance, and ensuring nutritional rehabilitation. Despite intestinal changes due to malnutrition, intact milk provides a suitable protein source for formulation of recovery diets. As long as protein-energy malnutrition remains prevalent, research to improve its treatment will remain a high investigative priority.

Adaptation, Physiological↗
PubMed1985

Intestinal metabolism of a random-bonded polyglucose bulking agent in humans: in vitro and in vivo studies of hydrogen evolution.

In vivo and in vitro experiments were conducted to determine the extent of intestinal fermentation of polydextrose, a random-bonded glucose polymer proposed as a low-calorie bulking agent in weight-reducing diets. The evolution of hydrogen gas was the index of bacterial fermentation. Oral ingestion of 15 gm polydextrose by healthy volunteers produced a flat breath hydrogen response, equivalent to that of glucose, and significantly less than that of lactulose. In vitro incubation of a polydextrose solution with fecal homogenates produced 24.8% of the hydrogen production of a comparable glucose solution. When either milk or lactose-hydrolyzed milk containing 18 gm intrinsic carbohydrate was mixed with 18 gm polydextrose, a significantly greater breath hydrogen excretion was observed as compared with the respective beverages alone. There is minimal in vivo fermentation of polydextrose when consumed alone, but when mixed into foods it may produce carbohydrate malabsorption or itself be more readily fermented.

Adult↗
PubMed1984

The effect of dietary lactose on the early recovery from protein-energy malnutrition. I. Clinical and anthropometric indices.

To assess the advisability of using lactose-containing formulas in the rehabilitation of severely malnourished children, indices of clinical recovery, growth and restoration of body proteins and gastrointestinal function were measured longitudinally during the initial 45 days of hospitalization in 20 male, preschool children with kwashiorkor and marasmic-kwashiorkor. All patients received a diet based on cows' milk, but half were allocated to a formula pretreated with beta-galactosidase to hydrolyze the lactose, while the others received the untreated, intact milk. The groups were identical with respect to clinical criteria on admission. For the final 37 days of the protocol, the subjects received 4 g of protein and 150 kcal of energy per kg per day. More diarrhea was experienced by the intact lactose group during early hospitalization. Overall, recovery was satisfactory in both cohorts, and there were no differences in rates of growth, body protein repletion, restoration of energy reserves nor intestinal functions. In conclusion, the routine reduction of lactose content from a milk-based diet for severe protein-energy malnutrition offers no advantages.

Animals↗
PubMed1984

The effect of dietary lactose on the early recovery from protein-energy malnutrition. II. Indices of nutrient absorption.

Absorption of dietary energy, nitrogen, carbohydrates and calcium, and retention of nitrogen and calcium were studied in 20 children with protein-energy malnutrition of the edematous type, using metabolic balance techniques and breath H2 analysis, to assess the advisability of using lactose-containing formulas in the rehabilitation of severely malnourished children. Ten patients received for 45 days a diet formula based on cows' milk (intact milk) and 10 similar children received the same formula pretreated with beta-galactosidase to hydrolyze the lactose (hydrolyzed milk). Dietary intakes were gradually increased to reach, on the 8th day, 4 g of protein and 150 kcal/kg. There were no differences between groups with respect to absorption or retention of the index nutrients. Postprandial carbohydrate malabsorption was occasionally observed in two patients with servings of the intact milk formula, and in one with the hydrolyzed milk diet. When the nutritional quality of a diet is assessed, the amount of nutrients that are absorbed and utilized are more important than the small, incompletely absorbed fractions that do not have significant metabolic or clinical implications. Therefore, the use of milk as the protein source for recovery diets is not contraindicated in the routine treatment of PEM.

Animals↗
PubMed1984

Enzyme replacement therapy for primary adult lactase deficiency. Effective reduction of lactose malabsorption and milk intolerance by direct addition of beta-galactosidase to milk at mealtime.

The addition of microbial beta-galactosidases directly to milk at mealtime represents a potential "enzyme replacement therapy" for primary lactase deficiency. We used the hydrogen breath test as the index of incomplete carbohydrate absorption to assess the efficacy of two enzymes--one from yeast, Kluyveromyces lactis (LactAid), and the other from the fungus Aspergillus niger (Lactase N)--to assist in the hydrolysis of 18 g of lactose in 360 ml (12 oz) of whole milk when consumed by an adult lactose malabsorber. Graded amounts of Lactase N produced, at best, a 53% relative reduction in breath hydrogen excretion, whereas quantitative elimination of excess hydrogen excretion was produced by 1 and 1.5 g of LactAid. A double-blind, controlled, crossover trial was subsequently performed in 50 healthy, unselected Mexican adults, to whom 360 ml of cow's milk was presented in the three forms in a randomized order: intact milk, prehydrolyzed milk, and milk to which 1 g of LactAid was added immediately before consumption. Among the 25 subjects with incomplete carbohydrate absorption with intact milk, adding enzyme 5-min before consumption produced a 62% reduction in breath hydrogen excretion, and symptoms of intolerance were significantly reduced. The feasibility of effective enzyme replacement therapy with a beta-galactosidase from K. lactis is demonstrated.

Adult↗
PubMed1984

Chromatograph with external column evaluated for determining breath hydrogen in clinical studies.

A novel breath-hydrogen analyzer involving an external chromatographic column in the form of a cartridge packed with molecular-sieve material and dessicant is described. The instrument incorporates a sintered SnO2 solid-state sensor into the detector, which registers a change in electrical potential in response to the adsorption of reducing gases; ambient room air is drawn through an activated charcoal filter by a small, internal pump and used as the carrier gas. Once calibrated with a gas of known H2 concentration, a digital meter registers the concentration of H2 in an unknown sample of breath air. The response is linear with concentration up to 160 microL/L. The external column is both necessary and effective for screening out contaminating reducing gases. The correlation coefficient for 250 gas samples measured simultaneously with an external-cartridge instrument and with an internal column chromatography is greater than 0.99. Results by the new analyzer corresponded 100% with those by the conventional machine for detecting carbohydrate malabsorption; for diagnosing efficient carbohydrate absorption, results by the two instruments agreed for 96% of the tests.

Adsorption↗
PubMed1983

Evaluation of a rapid breath hydrogen analyzer for clinical studies of carbohydrate absorption.

A second-generation gas chromatograph for the analysis of H2 in expired air has been developed. It incorporates a solid-state detector with high sensitivity for H2 and has a small, internal pump which supplies air as the carrier gas, thus eliminating the need for a large tank of compressed gas for the carrier. A reference gas of known H2 concentration is, of course, still required. The entire system weighs 6.0 kg and is completely portable, requiring only 120 V electric current for use. The instrument has a mean intersample interval of less than 2 min, with H2 concentration registered on a digital display. The output has a track-hold feature which permits the output, in parts per million H2, to be retained by the meter so the reading can be verified. The chromatogram can also be recorded on a conventional analog strip-chart recorder. The sensitivity and precision are superior to those of a thermal conductivity H2 gas chromatograph. Moreover, the rapid response time encourages frequent calibration checks with the reference gas. This analyzer offers significant advantages over previous H2-measuring systems for breath-analysis tests used both for diagnostic clinical practice and for field studies of nutritional assessment.

Breath Tests↗
PubMed1983

Studies on the bioavailability of zinc in humans: intestinal interaction of tin and zinc.

Mineral/mineral interactions at the intestinal level are important in animal nutrition and toxicology, but only limited understanding of their extent or importance in humans has been developed. An inhibitory interaction of dietary tin on zinc retention has been recently described from human metabolic studies. We have explored the tin/zinc interaction using the change-in-plasma-zinc-concentration method with a standard dosage of 12.5 mg of zinc as zinc sulfate in 100 ml of Coca-Cola. Sn/Zn ratios of 2:1, 4:1, and 8:1, constituted by addition of 25, 50, and 100 mg of tin as stannous chloride, had no significant overall effect on zinc uptake. The 100-mg dose of tin produced noxious gastrointestinal symptoms. Addition of iron as ferrous sulfate to form ratios of Sn/Fe/Zn of 1:1:1 and 2:2:1 with the standard zinc solution and the appropriate doses of tin produced a reduction of zinc absorption not dissimilar from that seen previously with zinc and iron alone, and addition of picolinic acid did not influence the uptake of zinc from the solution with the 2:2:1 Sn/Fe/Zn ratio.

Adult↗
PubMed1983

Studies on the bioavailability of zinc in humans: mechanism of the intestinal interaction of nonheme iron and zinc.

The mechanisms of the previously described competitive zinc:iron interaction were explored in healthy human volunteers, using the increment in plasma zinc concentration after an oral dose of 25 mg of zinc as zinc sulfate as the index of zinc absorption. Ferric iron in a 2:1 Fe/Zn ratio reduced the plasma uptake of zinc, but to a significantly lesser degree than ferrous iron; addition of 1 g of ascorbic acid increased the magnitude of the inhibitory effect of ferric iron to that seen with ferrous iron. An inverse relationship between some indices of iron status in adult women, or of parenteral iron administration in a child, and the magnitude of zinc:iron interaction was observed. Saturation of the intestinal mucosa with consecutive-day doses of therapeutic iron did not influence the uptake of zinc administered alone or in the context of a 2:1 ferrous iron:zinc ratio in solution. The results are most consistent with a combination of an intraluminal competition of the two minerals and an intracellular competition at a site "distal" to the regulatory step by which iron nutriture modulates the entry of iron into the body, but "proximal" to the site at which the daily administration of therapeutic doses of iron blocked the passage of dietary iron.

Adult↗
PubMed1983

Fecal reducing substances and breath hydrogen excretion as indicators of carbohydrate malabsorption.

Data from serial determinations of fecal volume, characteristics, pH, and reducing substances, and postprandial breath hydrogen (H2) concentrations in severely malnourished children receiving milk-based recovery diets were used to evaluate the quality of the correspondence among diagnostic indices for carbohydrate malabsorption, with specific emphasis on the comparison of breath H2 excretion and fecal reducing substances. Only postprandial breath H2 results for subjects with a proven capacity to mount an H2 response to the nonabsorbable disaccharide, lactulose, were included. There was a poor correlation between the diagnostic indication provided by the breath test and fecal reducing sugars. Biological considerations about the metabolism of unabsorbed carbohydrates in relation to colonic transit time and fecal flora may explain the poor degree of correlation. The two indices should not be considered interchangeable, but should be used selectively in accordance with the clinical situation.

Breath Tests↗
PubMed1983

Performance of genetically-colorblind individuals on a rapid dark adaptation test based on the Purkinje shift.

An experiment was conducted to determine whether or not genetic colorblindness would limit performance on a rapid dark adaptation test (RDAT) which is based on the Purkinje shift in retinal sensitivity to lower wavelengths of light energy under mesopic/scotopic conditions of illumination. No differences in RDAT performance between age-equivalent colorblind and non-colorblind subjects was observed.

Adult↗
PubMed1983

Time-course of cigarette smoke contamination of clinical hydrogen breath-analysis tests.

The time-course of the contamination of exogenous hydrogen from cigarette smoke on postprandial breath hydrogen concentration was evaluated in 10 subjects, six regular smokers and four occasional smokers. Breath hydrogen values were determined by gas chromatography 10 min, 5 min, and immediately prior to smoking a filter cigarette; during smoking from a sample of exhaled air containing smoke; and 5, 10, and 15 min after extinguishing the cigarette. A three- to 137-fold increase above basal hydrogen concentrations was produced by exhaled cigarette smoke, but most subjects had re-equilibrated to baseline values within 10 to 15 min after the cigarette. If subjects undergoing clinical hydrogen breath tests cannot refrain from smoking during the duration of the test, one should allow an interval of at least 15 min from the end of smoking to the collection of a breath sample.

Adult↗
PubMed1983

Sensitivity and specificity of the hydrogen breath-analysis test for detecting malabsorption of physiological doses of lactose.

We examined the changes in sensitivity and specificity that would occur with alterations in the sample-collection schedule and (or) cutoff criterion for the increase in hydrogen concentration in breath after administration of doses of lactose in the dietary range. In a breath-analysis test to classify individuals as lactose-absorbers or lactose-malabsorbers, 41 subjects drank 360 mL of intact cow's milk, containing 18 g of lactose, and breath samples were collected and analyzed at 30-min intervals for 5 h. An increase in H2 concentration of greater than or equal to 20 microL/L above basal values at any of the 10 intervals was diagnostic of malabsorption. Increases of greater than or equal to 18 or greater than or equal to 15 microL/L were only 85% as specific in classifying the same individuals. Reduction in the number of samples tested per subject uniformly reduced the sensitivity. However, a simplified procedure suitable for field studies (in which four samples--at 0, 2, 3, and 4 h--are collected and analyzed with greater than or equal to 20 microL/L as the cutoff value) gives 80% sensitivity and 100% specificity, as compared with the 11-sample procedure.

Adult↗