Search PubMed⌕ Search

Biomedical subjects

C Garza

Publications and source records attributed to C Garza.

At least 109 records · Page 6Linked to original sources
PubMed1983

Muscle electrolytes in malnutrition syndromes of children.

Muscle electrolyte composition has been studied in 10 infants with marasmus and eight children with kwashiorkor. The presence of altered muscle salt and water concentrations was confined in the latter nutritional syndrome. The marasmic infant, with equivalent or more severe nutritional wasting than the child with kwashiorkor, maintained a more normal muscle electrolyte concentration as indicated by a number of criteria. The pathophysiology of the altered muscle composition in kwashiorkor remains unclear; however, it appears to be more specific than due just to a depletion of available fat and muscle stores. Although possible endocrine mechanisms can be postulated to explain the change in muscle chemistry, the existing evidence is inadequate. Clearly, continuing research is warranted.

Adenosine Triphosphate↗
PubMed1983

Delayed complete functional lactase sufficiency in breast-fed infants.

Colonic fermentation of unabsorbed lactose was evaluated by measuring breath hydrogen (BH2) after a regular feeding in 17 white, normal, exclusively breast-fed infants 4-5 weeks of age. Interval breath samples were collected with a specially modified face mask and analyzed by gas chromatography for H2 and CO2 concentrations. Five infants (29%) produced 20 ppm or more of H2, four of whom underwent repeated testing. Three infants stopped producing over 20 ppm of H2 as they grew older. On a repeat evaluation, one of these three infants had levels over 20 ppm when other foods were introduced into his diet. The other continued to have elevated BH2 when weaned. Stools of infants with elevated BH2 levels had no detectable glucose, and pH was over 5.5. Weight-for-age of infants with elevated BH2 was at or above the 75th percentile. BH2 levels, normalized for the amount of breast milk ingested, fell significantly with age. These results show that complete small bowel absorption of lactose from breast milk does not occur in all white, normal, term, appropriate-for-gestational-age infants in the first months of life. The absence of glucose in the stool and the normal stool pH suggest that the unabsorbed lactose that produced H2 can be degraded in the colon.

Breast Feeding↗
PubMed1983

Cortisol and its possible role in regulation of sodium and potassium in human milk.

Cortisol (F), Na, and K were measured in human milk samples taken every 4 h during 28 24-h cycles in 19 subjects. F in milk, measured by radioimmunoassay of unchromatographed extracts, demonstrated a circadian variation similar to that of plasma F and was dexamethasone-suppressible. Values ranged from 220 +/- 41 (SE) ng/dl at 2300 h to 1,214 +/- 210 at 0700 h. When milk extracts were chromatographed, a similar circadian variation was seen, and F ranged from 87 +/- 27 (SE) ng/dl at 2300 h to 784 +/- 164 at 700 h. The morning values of F exceeded previous estimates of corticosteroid binding capacity in milk, indicating the possibility of significant levels of unbound F. The subjects were divided into three groups according to time postpartum: I, 3.5-6 wk; II, 8-18 wk, and III, 20-32 wk. In milk, normalized values of F (unchromatographed) and electrolytes (x/means) were compared, with x the value at time t and means the mean value for a 24-h cycle. A significant circadian variation was seen in milk for (x/means)Na, (x/means)K, (x/means)Na/K, and x/means)F. Correlation of (x/means)F with (x/means)Na 4 h later was negative in all three groups (r = -0.36 to -0.56, P less than 0.10-0.001) as was (x/means)F vs. (x/means)Na/K (r = -0.33 to -0.61, P less than 0.10-0.001); (x/means)F vs. (x/means)K 4 h later was positive (r = 0.38 to 0.52, P less than 0.05-0.001). Dexamethasone administration caused a significant decrease in milk means Na and an increase in meansK in all five subjects (P less than 0.01). Thus, milk Na and K concentrations appeared regulated by adrenal corticosteroids.

Adolescent↗
PubMed1983

Modeling the growth pattern of premature infants.

A model for the accretion of weight of premature infants from birth to hospital discharge has been studied for goodness of fit and other qualities. The model has been fitted to data for weight of 22 infants with typical growth patterns and to a full range of standard premature growth curves. It was found that the model fitted well to the data suggesting its value as an analytic tool in studies of premature growth.

Growth↗
PubMed1982

Effects of methods of collection and storage on nutrients in human milk.

The effects of collection technique, storage container, and the duration and temperature of storage on selected nutrient concentrations in mature human milk were evaluated. Milk samples were collected during the fourth week of lactation from women 20-35 years of age by hand expression or suction. Greater volumes and fat concentrations were observed in milks collected by suction. Vitamin A, zinc, iron, copper, sodium, and protein nitrogen concentrations were not affected by storage of milk in either pyrex or polypropylene containers for up to 24 h. The storage temperature had a significant effect on protein nitrogen and ascorbic acid concentrations. These findings indicate that collection methods and storage procedures used for comparatively brief periods will affect the concentrations of selected nutrients of mature human milk. Specific recommendations are made for the collection and storage of milk.

Adult↗
PubMed1982

Effects of prematurity on the immunologic system in human milk.

A longitudinal study of the effect of prematurity on the development of several components of the immunologic system in human milk was performed. Milk was obtained during the second through the twelfth week after parturition. The mean concentrations of lactoferrin and lysozyme were greater in preterm than in term milk during each interval of lactation. The patterns of change in these components were similar for term and preterm milk. Secretory IgA was the predominant form of IgA in preterm milk. The mean concentrations of IgA were greater in preterm milk throughout the study period. Furthermore, total and secretory IgA levels in preterm milk rose linearly during the sixth through the twelfth week, whereas the concentrations of IgA did not change in term milk during that period. In most preterm mothers, secretory IgA antibodies to Escherichia coli somatic antigens increased as lactation proceeded. These increments in specific antibodies usually did not correlate with changes in total secretory IgA. In addition, leukocyte counts in preterm milk were usually lower at two weeks and higher at 12 weeks than in term milk. Thus the concentrations of certain components of the immunologic system in human milk are altered by premature delivery. A decrease in milk volume may account for some changes, whereas certain alterations may be the result of other consequences of premature delivery or less stimulation by the premature infant.

Adult↗
PubMed1982

Immunologic factors in human milk during the first year of lactation.

The effects of the duration of lactation upon lactoferrin, lysozyme, total IgA, SIgA, SIgA antibodies to Escherichia coli somatic antigens and leukocytes in human milk were investigated. Longitudinal and cross-sectional studies were performed with milk collected from women 20 to 35 years of age during te first year of lactation. Collection and storage conditions and immunologic analyses were controlled to minimize confounding variables. The concentrations of lactoferrin, total IgA, and leukocytes and the uptake of 3H-thymidine by phytohemagglutinin-stimulated lymphocytes fell during the first several weeks of lactation; afterward, the levels of lactoferrin and IgA stabilized. Approximately 90% of total IgA in human milk during the year was SIgA. Secretory IgA antibody titers to E. coli increased in some individuals studied longitudinally suggesting that the enteromammary gland pathway of SIgA antibody production was active after several weeks of lactation. Moreover, the concentrations of lysozyme, after falling to a nadir of 20 to 30 micrograms/ml at 2 to 4 weeks, rose to 200 to 300 micrograms/ml by six months and remained elevated. The immunologic system in human milk undergoes remarkable changes which may represent adaptations for the recipient infant.

Adult↗
PubMed1982

Diurnal and longitudinal variations in human milk sodium and potassium: implication for nutrition and physiology.

Human milk sodium ([Nal]) and potassium ([K)] concentrations were measured every 4 h for 24 h in 28 subjects 3.5 to 32 wk postpartum. A diurnal variation in milk Na was seen, which was reciprocal to K. Significant negative correlations between Na and K were seen in these periods: 3.5 to 6; 8 to 18, 20 to 32 wk postpartum (p less than 0.01 for each). The mean 24 h milk sodium concentrations (x(Na)) decreased between 3.5 and 18 wk postpartum (p less than 0.005 by paired t test). Changes in mean potassium (-XK) were not statistically significant. Diet apparently does not affect milk Na. Administration of a low Na diet: 10.8 +/- .9 (SD) mEq Na/day and 60 to 100 mEq K/day for 2 days did not change x(Na). But urinary Na decreased 7-fold as aldosterone increased 5-fold. No significant correlation was seen between 24 h Na excretion in urine and x(Na) in milk (n = 51). A significant positive correlation was seen between urinary K and -XK in milk (r = 0.36), p less than 0.001).

Adolescent↗
PubMed1982

Chemical maturation in growing guinea pigs.

Twenty-seven guinea pigs were analyzed chemically for total body water (TBW), fat, nitrogen (N), calcium (Ca), and sodium (Na); 26 were analyzed for potassium (K). Body weights ranged between 82 and 877 g. The data were analyzed by regression analysis. If the slope of a regression line did not differ significantly from zero (P less than 0.05), the mean and standard deviation were calculated. The slopes of the regression lines were significant for Na [meq/100 g fat-free wet weight (FFWW)] on body weight in grams, K in milliequivalents on FFWW in grams, and total body fat (TBF) (g) on body weight in grams. The means and standard deviations for the remaining constituents were in g/100 g FFWW; 76.0 +/- 2.5 for TBW and 2.52 +/- 0.28 for N, and in meq/100 g FFWW Ca 58.26 +/- 7.35 and K 6.35 +/- 0.74, and % TBF 8.57 +/- 3.44. The values for the following ratios were: K/N 2.609 +/- 0.247; K/TBW 0.087 +/- 0.011; and N/TBW 0.033 +/- 0.004 (K is in meq, N and H2O in g). The suggestion that the lower figure for TBW reported by earlier investigators compared to the present data could be the result of a systematic methodological error is discussed.

Adipose Tissue↗
PubMed1982

Comparison of measured and estimated fat-free weight, fat, potassium and nitrogen of growing guinea pigs.

Total body water (TBW), potassium (TBK), nitrogen (N), and fat were measured chemically on 27 guinea pigs ranging in weight from 82-849 g. Measured fat-free wet weight (FFWW) is the difference between body weight and fat extracted with ether. Estimated FFWW is either TBW or TBK divided by a measured or assumed concentration of either water or K in the FFWW. The coefficients of correlation between measured and estimated values of FFWW were identical, r = 0.99 with the 3 different concentration values used for K. By paired t analysis there were significant differences statistically between measured and estimated FFWW with the K "constants" 68.1 and 62.5, but no difference with the "constant" 65.5. The correlation coefficients between measured and estimated FFWW from water were r = 0.96 with the "constant" 73.2 g/100 g FFWW, and r = 0.99 with the "constant" 76.0 g/100 g FFWW. By the paired t test, measured and estimated FFWW differed significantly only with the "constant" 73.2. In the calculation of fat from K concentrations, only the value 65.5 could be used. The coefficients of correlation for measured and estimated fat were significant, although low. There was no difference correlations between N and body cell mass, body weight and measured and estimated FFWW, and between body cell mass and body weight and measured and estimated FFWW. There was statistically no difference between measured and estimated N by the paired t test.

Animals↗
PubMed1981

Total body sodium, calcium, and chloride measured chemically and by neutron activation in guinea pigs.

Body sodium (Na), calcium (Ca), and chloride (Cl) of guinea pigs weighing between 227 and 600 g were measured by total body neutron activation analysis (TBNAA) followed by chemical analysis (CA) on 12-17 animals. Paired t test was used to compare any differences in the results obtained by the two methods. There was no significant difference in the results for the three elements. The means and standard deviation for Ca (g/100 g body wt) 1.070 +/- 0.132 (TBNAA) and 1.107 +/- 0.125 (CA); for Na 0.149 +/- 0.019 (TBNAA) and 0.143 +/- 0.021 (CA); and for Cl 0.126 +/- 0.009 (TBNAA) and 0.132 +/- 0.024 (CA). Neutron activation analysis alone, in a series of 27 animals, gave means (g/100 g body wt) and standard deviation of 1.110 +/- 0.084 for Ca, 0.120 +/- 0.009 for Cl, and 0.153 +/- 0.011 for Na. TBNAA has potential usefulness, particularly in longitudinal studies in the same animal, because of its accuracy and the rapidity and ease with which the measurements can be made.

Animals↗
PubMed1979

Appropriateness of milk use in international supplementary feeding programs.

Recognition of lactose intolerance, debate over the limitedness of dietary energy and protein in specific settings, and the appreciation for the uniqueness and appropriateness of human milk during the 1st yr of life have prompted reexamination of the use of milk in international feeding programs. Substantial proportions of preschool and school-age children from expected populations are lactose intolerant. However, studies in this county indicate that lactose intolerant preschool and early school-age children can tolerate amounts of milk usually consumed. Older individuals with symptomatic responses to milk also will often have similarly mild symptomatic responses to hydrolyzed lactose milk. Appropriately controlled studies in developing countries are planned or are underway to assess milk tolerance. In feeding programs designed to provide a protein supplement, milk continues to be a very attractive option. The question of how much milk protein must be given and how often it should be provided to make a significant impact on a population's well-being depends on an evaluation of the data base describing protein intakes and needs for specific populations. These types of data for most populations are inadequate.

Adolescent↗
PubMed1978

Human protein requirements: interrelationships between energy intake and nitrogen balance in young men consuming the 1973 FAO/WHO safe level of egg protein, with added non-essential amino acids.

Our recent studies have shown that the 1973 FAO/WHO "safe level of intake" of egg protein (0.57 g/kg/day) is inadequate for maintaining protein nutritional status in young men receiving generous energy intakes. Therefore, an experiment was conducted to determine nitrogen (N) balance and the energy intake needed to support it when supplementary N, equivalent to 0.23 g of protein (N X 6.25)/kg/day from a nonessential amino acid mixture, was added to a diet containing 0.57 g of egg protein/kg/day. Four young men, 20 to 21 years old, participated in the 58- to 79-day metabolic N balance study. This group required significantly lower energy intakes to maintain N balance than a previously studied group fed only 0.57 g of egg protein under identical conditions. The energy intakes predicted to maintain N balance were approximately 10 to 15% less than the requirements estimate from body weight and N balance data. Present results, although based on a limited number of subjects, suggest that total N may be the limiting factor in short-term N balance at the 1973 FAO/WHO egg protein intake level for a significant proportion of young adult male populations. Long-term metabolic studies will be necessary before the practical significance of the observations can be determined.

Adult↗
PubMed1977

Human protein requirements: a long-term metabolic nitrogen balance study in young men to evaulate the 1973 FAO/WHO safe level of egg protein intake.

Six Caucasion male MIT students, age 19 to 23 years, were given a formula diet providing 0.59 g egg protein/kg body weight/day and energy intakes approximately 10% above their usual requirements. Four subjects continued on this diet for 81 to 89 days, but for the two the protein intake was increased after 50 and 59 days because of an excessive rise in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. The elevated serum AST and ALT activities fell to normal rapidly when these subjects received a diet providing 1.5 g protein/kg/day from skim milk powder. Body weight increased in five of the subjects. Four showed cumulative negative N balances, and all showed a net loss of total body 40K, which was significant in three. These findings indicate that the 1973 FAO/WHO "safe level" of egg protein intake of 0.57 g/kg is not sufficient for long-term maintenance of most healthy young men. Moreover, the greater N losses calculated from 40K and creatinine measurements than from the N balance data suggest an integumental N loww approximating 15 mg/kg rather than the 5 mg of the 1973 allowances.

Adult↗