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Biomedical subjects

D S Lewis

Publications and source records attributed to D S Lewis.

At least 37 records · Page 2Linked to original sources
PubMed1991

Programming of cholesterol metabolism by breast or formula feeding.

We tested the hypothesis that breast or formula feeding and cholesterol intake during the neonatal period influence cholesterol metabolism and arterial fatty streaks in young adult baboons. Genetic variation was controlled by randomly assigning half-sib sire progeny to a factorial dietary design. We measured serum cholesterol and lipoprotein cholesterol concentrations enzymically and cholesterol production and bile acid excretion rates isotopically. The bile cholesterol saturation index was calculated from enzymic analyses of cholesterol, bile salt and phospholipid concentrations in gallbladder bile. Breast-fed baboons had higher serum VLDL + LDL cholesterol/HDL cholesterol ratios in the early postweaning period (six months) until adulthood (7-8 years) than formula-fed baboons. In adulthood a high cholesterol diet increased bile acid excretion by approximately 40% in formula-fed baboons but did not significantly increase the bile acid excretion rate among breast-fed animals. Adult baboons breast fed as infants also had an approximately 8% lower cholesterol production rate than formula-fed animals and a 20% higher bile cholesterol saturation index. The level of cholesterol in the infant formulas influenced cholesterol metabolism in adulthood but not serum lipoprotein concentrations. As young adults, breast-fed baboons had more extensive arterial fatty streaks than formula-fed baboons. This difference could be accounted for by differences in the lipoprotein ratios. These results demonstrate that breast and formula feeding differentially modify cholesterol metabolism. This may influence the development of chronic diseases.

Adult↗
PubMed1991

Care of the diabetic patient who is NPO for a procedure.

Nursing care of the diabetic patient who is NPO for a procedure presents many challenges. Unwise treatment and care decisions may be made because of misunderstanding about the body's basal need for insulin. "Hold-the-insulin" routines are dangerous. Guidelines for management of these patients can provide the necessary information and confidence for excellent nursing care.

Blood Glucose↗
PubMed1991

Maternal weight and sire group, not caloric intake, influence adipocyte volume in infant female baboons.

We tested the hypothesis that overfeeding with a high caloric (concentrated) formula increases growth without influencing adipocyte volume in preweaning infant baboons. Female infant baboons from three sires and 25 dams were fed either 67.5 kcal (normal formula) or 94.5 kcal (concentrated formula)/100 g Similac formula. Immediately before weaning (19 wk), adipocyte volume was measured in biopsied adipose tissue from omentum, flank, and popliteal depots. From birth until weaning, infants fed the concentrated formula consumed 20% more total calories, averaged 15% more calories/kg/wk, and gained 14% more weight than normally fed infants. Adipocyte volume differed significantly among different sites (omentum greater than popliteal greater than flank) and among different sire groups. Increased caloric intake alone did not increase adipocyte volume. There was a small but significant sire by infant formula interaction on adipocyte volume. When fed the concentrated formula, progeny from one sire had larger adipocytes than normally fed infants, whereas progeny from the other two sires had smaller adipocytes or adipocytes that were comparable to infants fed normal formula. Variability in adipocyte volume at 19 wk of age was best accounted for by maternal weight and sire group (omentum R2 = 0.334, p = 0.026; flank R2 = 0.532, p = 0.01; popliteal R2 = 0.482, p = 0.01) and not by caloric intake. These results suggest that the level of triglyceride deposition into adipocytes attained during preweaning growth is determined to a greater extent by genetic and other factors rather than caloric intake.

Adipose Tissue↗
PubMed1990

Feeding influences plasma cortisol levels during preweaning life in baboons.

The effect of feeding on plasma cortisol concentrations was examined in neonate (preweaning), infant (postweaning), and adult baboons (Papio cynocephalus). Neonates were bottle fed four times daily, infants twice daily, and adults once daily. In neonates, plasma cortisol declined within 30 min after feeding. This decline in plasma cortisol was dependent on ingestion of formula and was independent of the time of feeding. During the day, cortisol fluctuations were synchronized with feeding times: peak levels occurred before feeding and trough levels occurred 30-60 min after feeding. Plasma adrenocorticotropic hormone (ACTH) declined within 30 min after feeding but returned to prefeeding levels at 60 min after feeding and did not exhibit significant variation associated with feeding times as did cortisol. The decline in plasma cortisol after feeding in neonates was delayed with increasing age. By 18 wk, the feed-related decline in plasma cortisol was delayed until 60 min after feeding compared with 30 min at age of 8 wk. After weaning, the decline in plasma cortisol after feeding was delayed until 90 min, and there was no effect of feeding in the afternoon on plasma cortisol. Finally, there was no significant decline at all in adult baboons greater than 6 yr of age. These results demonstrate plasma cortisol concentration is associated with feeding in neonates fed formula. The cortisol-feeding rhythm changes before weaning, and after weaning it begins to disappear, until it is completely absent in adults.

Adrenocorticotropic Hormone↗
PubMed1989

A quality assurance program for human immunodeficiency virus seropositivity screening of dried-blood spot specimens.

Epidemiologic projects have been implemented for using dried-blood spot (DBS) specimens routinely collected on filter paper from neonates as a seroepidemiologic resource to monitor seroprevalence of human immunodeficiency virus (HIV) among childbearing women. To ensure the quality of the data base produced from the national and other epidemiologic surveys, a quality assurance program was developed to interact with all the neonatal screening laboratories. The focus of the Centers for Disease Control's quality assurance program for HIV seropositivity testing of neonatal blood specimens is to maintain a national program to produce, certify, and provide external quality control materials as DBSs on filter paper, to monitor the filter paper matrix, to operate an external performance surveillance program, and to provide other special and consultative services. The dried-blood control and surveillance materials are certified by rigorous testing for accuracy, stability, and homogeneity. Preliminary results from the first performance evaluation of screening laboratories indicated excellent performance.

AIDS Serodiagnosis↗
PubMed1989

Influence of preweaning food intake on body composition of young adult baboons.

The hypothesis that infant overnutrition increases fat cell number and promotes obesity in the young adult primate was tested. Newborn baboons were fed similar volumes of Similac formulas with caloric densities of 40.5 (underfed, n = 8), 67.5 (normally fed, n = 12), and 94.5 (overfed, n = 12) kcal/100 g formula until 4 mo of age. Afterwards all baboons were fed the same diet until they were young adults. At 5 yr of age body composition, mean fat cell size, and total fat cell number were measured. Infant food intake did not significantly influence body composition or fat cell number in the 5-yr-old male baboons. Five-year-old female baboons, overfed as infants, had significantly greater body fat mass, percent of body mass that was fat, and mean fat cell volume compared with females that were underfed or normally fed as infants. There was no difference in total fat cell number between the obese baboons that were overfed as infants and the lean baboons that were underfed or normally fed as infants. Fat cell number was not associated with body fat content; males had more fat cells than did females. These results demonstrate that infant overnutrition in a primate species promotes obesity in young adult females by increasing primarily fat cell size and not fat cell number.

Adipose Tissue↗
PubMed1986

Effects of dietary cholesterol on adipose tissue lipoprotein lipase in the baboon.

The effects of infant diet (breast milk or formula containing 2, 30 or 60 mg/dl cholesterol) and subsequent dietary cholesterol (0.02, 1.0 or 1.7 mg/kcal) and fat (saturated or unsaturated) on heparin-releasable lipolytic activity from omental adipose tissue was estimated from 99 baboons of 5-8 years of age. This lipase activity was characterized as lipoprotein lipase based on salt inhibition and apolipoprotein C-II activation. Lipoprotein lipase activity released from adipose tissue by heparin was significantly (P less than 0.002) lower in high cholesterol-fed baboons than in those fed low cholesterol. Most of this difference was due to impaired long-term heparin release of lipoprotein lipase. Adipose tissue lipoprotein lipase increased with increasing fat cell size regardless of diet, but there was no effect of diet on adipocyte size. There were no significant effects of infant cholesterol intake nor adult saturated or unsaturated fat on lipoprotein lipase activity. Adult baboons breast fed as infants had lower adipose tissue lipoprotein lipase activity (P less than 0.07) than adults fed formula as infants.

Adipose Tissue↗
PubMed1986

Use of NMR for measurement of total body water and estimation of body fat.

A nuclear magnetic resonance (NMR) method is described for quantitatively measuring total body water (TBW) and for estimating the fat content of baboons. The hydrogen associated with water was measured as the amplitude of the free-induction decay voltage following a series of 90 degree radio frequency pulses at the Lamour frequency for hydrogen with a pulse length of 14 microseconds and a peak measuring time of 50 microseconds. TBW was calculated by multiplying the peak amplitude (volts) by the experimentally determined constant for a water standard (g water/V). This NMR method yielded TBW contents similar to those obtained in the same baboons by direct gravimetric procedures. In contrast, the widely used 3H2O-dilution method usually and variably overestimated body water. By providing an accurate measure of body water, this NMR procedure provides a rapid, noninvasive, reasonably accurate way of estimating body fat content.

Adipose Tissue↗
PubMed1986

Total body water-to-lean body mass ratio in baboons (Papio sp.) of varying adiposity.

Total body water (TBW), lean body mass (LBM), and triglyceride mass were measured in 23 5-yr-old baboons (13 females and 10 males). Male baboons weighed more, had more LBM, more TBW, and contained less triglyceride mass per unit body weight than female baboons. Among all baboons, triglyceride mass per unit body weight ranged from 2.4 to 33.5%. The ratio TBW:LBM ranged from 0.70 to 0.92, increasing (r = 0.98) with increased body triglyceride content (both percent and absolute mass) in both male and female baboons. However, the water content per unit weight of tissues free of fat cells (liver, lungs, kidneys, central nervous system, eyes, tongue) was nearly constant at 0.73 +/- 0.02. The increase in TBW:LBM is more than can be expected from the water in the increased adipose tissue mass. We conclude that TBW:LBM is not constant but is influenced by body triglyceride content in baboons.

Adipose Tissue↗
PubMed1986

Preweaning food intake influences the adiposity of young adult baboons.

The hypothesis that preweaning nutrition influences adult fat cell number and adiposity was tested in baboons. Newborn baboons were fed Similac formulas with caloric densities of 40.5 kcal (underfed), 67.5 kcal (fed normally), and 94.5 kcal (overfed) per 100 g formula. From weaning (16 wk) until necropsy at 5 yr of age all baboons were fed the same diet. At necropsy, fat cell number and fat cell size in 10 fat depots were measured. Female baboons overfed as infants had markedly greater fat depot mass, primarily because of fat cell hypertrophy, than normally fed or underfed females. Overfed male baboons had a greater fat mass in 4 of 10 depots compared with males underfed or fed normally as infants. Underfeeding did not affect body weight, nor adipose mass of either sex. The results show that infant food intake does not have a major influence on the fat cell number of young adult baboons.

Adipose Tissue↗
PubMed1985

Prolymphocytic leukemia of B cell type: rearranged immunoglobulin (Ig) genes with defective Ig production.

An unusual case of prolymphocytic leukemia of the B cell type (B-PLL) in a 79-year-old patient is reported. The clinical and cytomorphological features of the disease were typical of B-PLL, but membrane and cytoplasmic immunoglobulins (Ig) could not be demonstrated by immunofluorescence techniques; 3% to 4% of the cells were shown to have IgG kappa in the cytoplasm by a more sensitive immunoperoxidase method. The cells were unreactive with a panel of monoclonal antibodies against T cell antigens but they were positive with B cell lineage reagents: FMC4, anti-HLA-Dr determinants; FMC7, which reacts with most B-PLL; anti-B1 and anti-B4, which react with most B cell leukemias. Analysis of Ig genes at the DNA level demonstrated that both heavy-chain alleles and one kappa chain allele were rearranged, confirming that the patient's cells were of B lineage. Chromosome analysis revealed a consistent abnormality, t(17;21)(p11;p11), in all cells and, in addition, a 14q+ marker in 10% of the cells. This study highlights the value of DNA analysis techniques for the characterization of neoplastic B cells. The low rate of expression of Ig genes, despite their rearrangement, suggests that a specific transcriptional or posttranscriptional defect must exist in these cells.

Aged↗
PubMed1984

Effect of interaction of gender and energy intake on lean body mass and fat mass gain in infant baboons.

The hypothesis that energy intake influences differently the composition of mass gain during the preweaning period was tested in male and female baboons. Infant baboons were fed either a high (92 kcal/100 g formula) or a low (49 kcal/100 g formula) caloric formula from birth. Body mass, lean body mass and fat mass of each baboon were measured directly at weaning (18 weeks of age). Lean mass and fat mass gained from birth to 18 weeks was estimated by using body composition data from eight newborn baboons. Both energy intake and gender significantly influenced gain of total mass, lean mass and fat mass. There was a significant gender by diet interaction effect on the gain of fat mass. When fed the high caloric formula, males gained 145 g more lean mass than females, but the increase of fat mass was approximately the same. In contrast, on the low caloric formula, males gained 150 g more lean mass than females but 74 g less fat mass than females. These results indicate that fundamental differences in the development of lean mass and fat mass exist between male and female baboons during preweaning life.

Adipose Tissue↗
PubMed1983

Preweaning nutrition and fat development in baboons.

Using the baboon as a model, we tested the hypothesis that preweaning food intake influences the number of adipocytes at weaning. Two groups of 12 newborn baboons each were fed either a concentrated or a diluted Similac formula from birth to 18 weeks of age. Baboons fed the concentrated Similac were 38% heavier (P less than 0.01) and had 87% more fat mass (P less than 0.01) than the baboons fed diluted Similac. The mean adipocyte volume and adipocyte number were measured directly in 10 individual fat depots, and the total number of adipocytes were estimated for each baboon. The difference in fat mass was due to differences (P less than 0.01) in mean adipocyte volume, which was 0.22 nl in overfed baboons and 0.09 nl in underfed baboons. There was no significant diet effect on the estimated total number of fat cells; nor on 8 of 10 depots in which adipocyte number was directly measured. These results indicate that, in baboons, preweaning caloric intake has little or no influence on the number of fat cells at the age of weaning.

Adipose Tissue↗