Biomedical subjects

C Garza

Publications and source records attributed to C Garza.

At least 91 records · Page 5Linked to original sources

PubMed1985

Free fatty acids in the development of breast milk jaundice.

The incubation of milk, at 4 degrees C, from mothers of infants with breast milk jaundice (BMJ) is reported to result in significantly higher levels of free fatty acids (FFA) compared with milk from controls. Single milk samples collected under standard conditions were obtained from four mothers of infants with BMJ and 14 control donors matched for stage of lactation. Milk samples were analyzed for the concentrations of FFA, using thin-layer gas chromatographic techniques. In addition, serum total fatty acids were measured in mothers and infants. The concentrations of FFA increased after storage of the milk from both the jaundiced and control groups. No differences were observed in the composition of milk FFA before or after incubation, when respective values were compared between these two groups. Similarly, no differences were detected in serum total fatty acids in either infants or mothers. The observation that increased levels of FFA in milk are associated with BMJ was not confirmed.

Adult↗

PubMed1985

Absorption and tolerance of lactose in infants recovering from severe diarrhea.

Nineteen infants were challenged during their convalescence from severe diarrhea with a lactose-containing meal. Twenty-four hour intake, pre- and post-challenge breath H2 levels, clinical responses, and growth were measured at approximately biweekly intervals for 3 months beginning 1 month after hospital discharge. Ten lactose-tolerant infants were assigned randomly to receive one of two formulas similar in composition except for carbohydrates: lactose (Group L) (n = 6) and sucrose (Group S) (n = 4). Infants in Group L had greater intakes and growth rates during the initial 15 days of the study. No difference in weight for age z-scores was detected between groups at the end of the observation period. Infants in Group L had higher baseline and peak breath H2 levels indicating greater colonic carbohydrate fermentation than infants in Group S: however, breath H2 levels were not predictive of tolerance to lactose-containing meals. Carbohydrate absorption by infants in Group S appeared to exceed that of infants in Group L. Thus, colonic fermentation of malabsorbed carbohydrate may have prevented diarrhea and allowed acceptable rates of catch-up growth.

Diarrhea, Infantile↗

PubMed1985

An acoustic plethysmograph to measure total infant body volume.

An acoustic plethysmograph intended to measure the body volume of premature infants has been developed using the principle of the Helmholtz resonator, in which the resonance frequency is dependent on the volume of the resonating cavity. A prototype system was built and used to measure the volume of inanimate objects and newborn miniature pigs. Results for inanimate objects agree within 1 percent with comparable measurements by water displacement. Results of the animal body volume measurements compare favorably (within an average of 1.1 percent) with those obtained using hydrostatic weighing.

Acoustics↗

PubMed1985

Use of resonating cavity to measure body volume.

A technique to estimate the body volume of newborns has been developed using the principle of the Helmholtz resonator. The change in the resonance frequency of a small cavity after an infant is placed inside can be used to determine the body volume of the infant. A prototype system, termed an acoustic plethysmograph, was built and used to measure the volume of newborn miniature pigs. Results of the animal body volume measurements compare favorably (within an average of 1.1%) with body volumes measured by hydrostatic weighing.

Animals↗

PubMed1985

Patterns of K/N ratios with growth of guinea pig, beagle, and pig.

The influence of age on patterns of K/N ratios (mEq/g) for fat-free whole body organs and tissues was analyzed for the guinea pig, ages 1 to 80 days (82 to 849 g); for the pig, 0 to 89 days (151 to 33,650); and for the beagle, 0 to 383 days (252 to 13,065 g). Strong correlations existed between total K, total N, and fat-free wet weight (FFWW). Mean whole body K/N ratios were 2.57 +/- 0.241 for guinea pigs, 2.53 +/- 0.50 for pigs, and 1.79 +/- 0.27 for beagles. Increase in body weight of the beagle and of the components, skeletal muscle and nonmuscle (whole animal minus skeletal muscle), were divisible into two statistically significant periods: the first from 0 to 62 days, the second from 63 to 383 days. For the first period, the K/N ratio for the whole animal was 1.70 +/- 0.33, for nonmuscle was 1.61 +/- 0.34, and for skeletal muscle was 2.08 +/- 0.50; for the second period, the values were 1.93 +/- 0.22, 1.25 +/- 0.18, and 2.82 +/- 0.83, respectively. Mean K/N ratios of organs and tissues of the pig and beagle differed significantly from mean whole body K/N ratios, with the exception of liver for the beagle and miscellaneous for the pig. Patterns of K/N ratios during increases in FFWW were species-specific for total body as well as for various tissues and organs. As FFWW increased, the whole body K/N ratio did not change significantly in the guinea pig, but decreased significantly in the pig because of the decreased ratio for skeletal muscle. As FFWW of the beagle increased in the first growth period, the slope for the whole body K/N ratio did not differ statistically from zero, although the mean measured ratio increased significantly for liver and skeletal muscle. This increase was counter-balanced by a statistically significant decrease in ratios for skin and skeleton. FFWW continued to increase in the second growth period and the whole body K/N ratio increased, primarily the result of significantly increased ratios for liver and skeletal muscle.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗

PubMed1985

Comparison of hand- and electric-operated breast pumps.

Volume, fat and energy contents were measured in human milk samples collected over 2 24-h periods with either an electric or hand-operated breast pump. The energy content was significantly higher and the variance for this measurement was significantly lower in samples obtained by the electric pump. The type of pump used is an important consideration when the content of energy and other nutrients associated with the fat compartment in human milk is to be evaluated. This observation is especially pertinent to cross-study comparisons, eg studies of well- and malnourished populations.

Adult↗

PubMed1984

Longitudinal changes in milk composition of mothers delivering preterm and term infants.

The concentrations of protein nitrogen (PN), non-protein nitrogen (NPN), energy, fat, sodium (Na), calcium (Ca), phosphorus (P), magnesium (Mg), and zinc (Zn) were determined in human milk from mothers giving birth to full-term (n = 13) and preterm infants (n = 8). Milk samples were collected under controlled conditions at two-week intervals for 12 weeks postpartum. Statistically significant differences in PN, Ca, and P concentrations were detected between the milk from mothers of preterm and term infants. The mean PN concentration in the preterm milk was statistically higher than that of term milk (198 vs. 164 mg N/dl), in contrast to the lower mean Ca (220 vs. 261 mg/l) and P (125 vs. 153 mg/l) concentrations detected in the preterm milk. No other differences in mean nutrient concentration were observed between the two groups. Concentrations of PN, NPN, Na, P, and Zn decreased over time. The concentration of Mg increased slightly. The content of fat, energy, and Ca did not change.

Adult↗

PubMed1984

Human milk intake and growth in exclusively breast-fed infants.

Milk intake and growth in 45 exclusively breast-fed infants were documented during the first 4 months of life. Energy and protein intakes were substantially less than current nutrient allowances. Energy intake declined significantly from 110 +/- 24 kcal/kg/day at 1 month to 71 +/- 17 kcal/kg/day at 4 months. Protein intake decreased from 1.6 +/- 0.3 gm/kg/day at 1 month to 0.9 +/- 0.2 gm/kg/day at 4 months. Infant growth progressed satisfactorily, compared with National Center for Health Statistics standards. A reevaluation of energy and protein intakes and allowances during infancy is merited.

Adolescent↗

PubMed1984

Rapid high-temperature treatment of human milk.

Increasing interest in feeding human milk to low-birth-weight infants raises concern about microbial contamination of milk that is pooled or stored. We examined the effect of rapid high-temperature treatment on bacteria and viruses and on the nutritional and immunologic quality of pooled human milk. Growth of endogenous bacteria and infectivity of added cytomegalovirus were undetectable after heating at 72 degrees C for 15 and 5 seconds, respectively. Folic acid and vitamins B1, B2, B6, and C were not affected, whereas bile salt-stimulated lipase was inactivated by these conditions. The concentration of lactoferrin and secretory IgA, and SIgA antibody activity were not changed by heating at 72 degrees C. Lysozyme concentration and enzymatic activity were increased significantly by heat treatment, suggesting that this component may be largely sequestered in milk. Our findings suggest that rapid high-temperature treatment can reduce microbial contamination without destroying the unique nutritional and immunologic qualities of human milk.

Animals↗

PubMed1984

Studies of human milk relevant to milk banking.

Issues regarding the efficacy of feeding human milk to premature infants include the development of optimal protocols for collecting, storing, and processing human milk. Studies of the nutritional and immunologic composition of milk produced by women who delivered term or premature infants and who weaned their infants gradually from human milk have been studied to identify optimal donors. The effects of specific collection, storage, and processing conditions on the composition of mature human milk also have been evaluated. Collection, storage, and processing conditions have distinct effects on specific functional components. The caloric content of milk, the content of nutrients carried in the lipid portion of milk, and selected enzymatic activities depend on the completeness with which the breast is emptied. Storing milk in polyethylene, polypropylene, and pyrex containers influences key immunologic components in human milk as do storage temperatures. None of the nutrient compositions of milks studied matched current estimates of the nutritional needs of premature infants. Importantly, both the concentrations and the pattern of change in nutrient and immunologic contents are distinct in milks of women delivering infants at term or prematurely. Further changes are seen during the process of gradual weaning.

Female↗

PubMed1984

A long-term metabolic balance study in young men to assess the nutritional quality of an isolated soy protein and beef proteins.

To evaluate the capacity of an isolated soy protein to maintain long-term protein nutritional status in healthy young adult men, an 84-day metabolic balance experiment was conducted in eight subjects. The sole source of protein intake was provided by the isolated soy protein, given at a level of 0.8 g (N X 6.25) per kg per day. In a second and similar study, four young men received 0.8 g protein and three subjects 0.68 g protein per kg per day from beef proteins for 60 to 81 days. Body weight, nitrogen balance, blood chemistries, and body composition (whole body 40K) were monitored throughout each study. Body nitrogen balances were maintained within the range of N equilibrium in both diet groups. Body cell mass, as judged from 40K measurements, did not reveal any deterioration in protein nutritional status. These observations confirm the prediction, derived from previous short-term. N balance studies, that the nutritional quality of isolated soy protein is high and that this plant protein can serve as the sole source of essential amino acids and nitrogen for protein maintenance in adults.

Adolescent↗

PubMed1984

Effect of maternal diet and body composition on lactational performance.

Milk production, dietary intake, and body composition of 45 lactating women were monitored for 4 months postpartum to examine the interrelationships of these maternal variables. A 3-day dietary record, 24-h test-weighing for determination of milk production, 24-h milk collection, anthropometric measurements, and water displacement for estimation of body fat were performed monthly. The overall mean (SD) energy intake was 2186 (463) kcal/day. Milk production (g/day) averaged 751 (130), 725 (131), 723 (114), and 740 (128) during the 4 sequential months. Weight postpartum was 64.6 (9.1) kg and was 59.3 (10.5) kg at 4 months. Body fat determined by water displacement averaged 28 (7)% at 1 month and 26 (8)% at 4 months. Estimations of body fat from skinfold thickness ranged from 28 (5)% postpartum to 27 (5)% at 4 months. Energy balance calculations based on the energy available from the diet plus the energy derived from tissue mobilization, minus the caloric equivalent of the milk, indicated sufficient energy available for maintenance and activity needs. Thus, it appears that successful lactation is compatible with gradual weight reduction and attainable with energy intakes less than current recommendations.

Adolescent↗

PubMed1984

Daily ingestion of immunologic components in human milk during the first four months of life.

The amounts of lactoferrin, lysozyme, SIgA and SIgA antibodies to E. coli somatic antigens in human milk ingested per day and per kg per day by breast-fed infants were determined during the first four months of life. A gradual decline in the amounts of lactoferrin, SIgA, and SIgA antibodies ingested per day or per kg per day was found, whereas the quantities of lysozyme ingested by the infants rose during that period. These data suggest that the production and secretion of these immunologic factors by the mammary gland may be linked to the ontogeny of the production or catabolism of those components at mucosal tissues of the recipient infant.

Antibodies, Bacterial↗

PubMed1984

Effect of different total parenteral nutrition fuel mixes on the body composition of infant miniature pigs.

At 10 d of age miniature pigs were randomized to receive either of two total parenteral nutrition fuel mixes; oral feedings were discontinued. Both groups received 170 kcal X kg-1 X d-1 and 11 g X kg-1 X d-1 of synthetic amino acids. Nonprotein energy was supplied as glucose in group A, whereas in group B, it was divided equally between glucose and fat. Blood samples were drawn on the second and eighth postoperative days for hematologic, biochemical, and hormonal measurements. On the ninth postoperative day, total body water was determined and the animals were killed for carcass analysis. The animals tolerated the intravenous nutrition without ill effects as indicated by both clinical and biochemical parameters. Group A had significantly elevated levels of insulin and a higher insulin/glucagon ratio than group B. Cortisol levels did not differ significantly between groups. Total body fat, nitrogen, ash, K, Na, Cl, Ca, and P were similar between groups. TBW was significantly greater in group A compared with group B. Extracellular space calculated from body Cl and plasma Cl was similar between groups.

Adipose Tissue↗

PubMed1984

The metabolic response to severe head injury.

Caloric expenditure and nitrogen balance were measured in 14 steroid-treated comatose head-injured patients acutely and up to 28 days after injury. During this period patients were fed with a continuous enteral infusion of a formula containing 2 Kcal/cc and 10 gm nitrogen/liter. Indirect calorimetry was carried out for 102 patient-days. The mean resting metabolic expenditure (RME) for nonsedated nonparalyzed patients was 138% +/- 37% of that expected for an uninjured resting person of equivalent age, sex, and body surface area. Nitrogen excretion was measured for 135 patient-days. The mean excretion was 20.2 +/- 6.4 gm/day. The mean protein caloric contribution was 23.9% +/- 6.7% and was greater than 25% for six patients, compared to normal values of 10% to 15%. Despite hyperalimentation, positive nitrogen balance for any 3-day period was achieved in only seven patients, and required replacement of 161% to 240% of RME with enterally administered formula. Head-injured patients had a metabolic response similar to that reported for patients with burns of 20% to 40% of the body surface.

Adolescent↗

PubMed1983

Changes in the nutrient composition of human milk during gradual weaning.

Six lactating women were recruited at 5 to 7 months postpartum for a study of milk composition during gradual weaning. At recruitment all subjects were exclusively breast-feeding their infants. The subjects were asked to reduce the frequency or duration of breast-feeding episodes by approximately one-third each month for a period of 3 months. Milk was collected before weaning began and at 2-wk intervals for 12 wk. The concentrations of protein and Na were 142 and 220% of base-line values, respectively, at the end of this period. Changes in fat composition were difficult to interpret. A linear trend was observed through wk 10, but values for wk 12 were similar to those obtained before weaning was initiated. The concentration of Fe at wk 12 was 172% of the base-line value. The concentration of Ca did not change and that of Zn fell to 58% of the base-line value at wk 12. The significance of the changes in nutrient concentrations, their relationship to the involution of the mammary gland, and the suitability of milk from this stage of lactation for milk banking are evaluated.

Adult↗

PubMed1983

A comparison of dietary methods in nutritional studies.

Dietary intakes of 40 lactating women were measured by a 7-day record (7DR) and compared with results using a 1-day record (1DR), 3-day record (3DR), and a newly developed food frequency form. The estimated intakes of energy, protein, calcium, phosphorus, and iron were used in the comparison. The subjects ranged from 3 wk to 6 months postpartum and all were totally breast-feeding their infants at the time of the study. The 7DR was recorded by the subjects and random days were chosen to provide 1DR and 3DR. The food frequency form is a method developed to estimate nutrient intakes based on the consumption of 105 food items. Intraclass correlation coefficients used to compare methods indicated good, moderate, and poor agreement for 3DR/7DR, 1DR/7DR, and food frequency form/7DR comparisons, respectively. Regression analysis was used to assess further the agreement between 3DR and 7DR. This analysis indicated that the 3DR cannot provide good individual estimates of nutrient intakes, but can provide a reasonable estimate of the general quality of the diet. Intakes also were classified as high (greater than 1 1/3 Recommended Daily Allowance), medium (2/3 to 1 1/3 Recommended Daily Allowance), or low (less than 2/3 Recommended Daily Allowance), and Cohen's kappa was used to measure agreement between methods. None of the intakes was found to agree with the 7DR classification. Intraindividual variation was found to be greater than interindividual variation.

Diet Surveys↗

PubMed1983

Evaluation of the deuterium dilution technique against the test-weighing procedure for the determination of breast milk intake.

A noninvasive isotopic method for the determination of milk intake in breast-fed infants was evaluated against the conventional method of test-weighing. In experiment 1, 48-h breast milk intake was estimated concurrently by the test-weighing procedure and by the deuterium dilution technique. In experiment 2, the isotopic method, modified to minimize fluctuations in water flux, was evaluated against a 24-h test-weighing. In experiment 1, the mean 48-h milk intake estimated by the isotopic method (1616 +/- 353 ml) was significantly higher than that measured by the test-weighing procedure (1449 +/- 234 ml) (p less than 0.01). In experiment 2, 24-h milk intake as determined by test-weighing and deuterium dilution averaged 878.0 +/- 188.1 and 690.7 +/- 141.4 ml/day, respectively, and differed significantly (p less than 0.001). The ability of the deuterium dilution method to predict values obtained by the test-weighing procedure was unsatisfactory for individual estimations. These experiments indicate that the deuterium dilution technique is unacceptable for the determination of breast-milk intake in individuals, but may be satisfactory for a population estimation.

Body Water↗