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Biomedical subjects

M Garg

Publications and source records attributed to M Garg.

At least 73 records · Page 4Linked to original sources
PubMed1989

Evidence for critical-period programming of intestinal transport function: variations in the dietary ratio of polyunsaturated to saturated fatty acids alters ontogeny of the rat intestine.

2-week isocaloric modifications in the dietary ratio of polyunsaturated/saturated fatty acids (P/S) alters intestinal transport in rats. This study was undertaken to test the hypotheses that (1) the fatty acid composition of a nutritionally adequate diet in early life has lasting consequences for active and passive intestinal transport processes; and (2) early life feeding experiences with diets of varying fatty acid composition influence the intestines' ability to adaptively up- or down-regulate intestinal transport in later life. Female Sprague-Dawley rats were weaned onto S or P and were maintained on these diets for 2, 10 or 12 weeks. An in vitro uptake technique was used in which the bulk phase was vigorously stirred to reduce the effective resistance of the intestinal unstirred water layer. P decreased and S increased the uptake of glucose, and this effect was progressive from 2 to 12 weeks. Switching from a P to an S diet decreased jejunal but increased ileal uptake of glucose, whereas switching from an S to a P diet was associated with a decline in both the jejunal and the ileal uptake of glucose. The ileal uptake of galactose increased as the animals grew on either P or S. Switching from P to S resulted in a decline in ileal uptake of galactose, whereas the opposite effect was observed when switching from S to P. The effect of feeding P or S on hexose uptake was influenced by the animals' dietary history: ileal glucose and galactose uptake was lower in animals fed P at an early age (PSP) than in animals fed P for the first time in later life (SSP). Jejunal glucose and galactose uptake was also lower in animals fed S at an early age (SPS) than in those fed S for the first time in later life (PPS). The alterations in the uptake of long-chain saturated and unsaturated fatty acids and cholesterol did not progress with longer periods of feeding, and in the jejunum, lipid uptake did not change when switching from P to S or S to P. Early feeding with P (PSP vs. SSP) was associated with lower jejunal uptake of 18:3 and lower ileal uptake of 12:0, whereas previous feeding with S (SPS vs. PPS) was associated with lower ileal uptake of cholesterol. The changes in uptake of hexoses and lipids was not explained by differences in the animals' food consumption, body or intestinal weight or mucosal surface area.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Specific antibodies in colostrum of north Indian mothers with special reference to their nutritional status.

The anti-S. typhi antibody is predominantly IgA class, and the anti-polio-antibody, antimeasles antibody, anti-E. Coli enterotoxin antibody and anti-S. typhi agglutinins were found adequate in the colostrum samples of well- and under-nourished mothers. No antibody against tetanus toxin was detectable in colostrum samples from mothers of both the groups, although they have been immunized against tetanus toxoid during pregnancy, suggesting thereby that the presence of specific antibody in the mother's breast secretions is associated with the enteromammary axis, leading to the homing of B-lymphocytes which have been specifically sensitized in the gut.

Antibodies, Bacterial↗
PubMed1989

An unusual case presentation: pericardial tamponade complicating central venous catheter.

The use of central venous catheters in very low birthweight infants to provide adequate calories for growth is an integral part of the care of the high-risk neonate. The use of surgically placed Broviac catheters has been associated with infectious and mechanical complications. Recently, there has been increasing use of silastic central venous catheters inserted through a peripheral vein and advanced to the right atrium. These catheters have a reported low rate of complications. However, we report a case of a very low birthweight infant in whom a peripherally inserted silastic catheter perforated the wall of the right atrial appendage and led to fatal pericardial tamponade. This is a very rare but nearly always fatal complication. It is potentially avoidable by careful placement of the tip of the central venous catheter, so that it is not impinging on a wall of the heart. Serial venograms may be useful to reconfirm the position of the catheter.

Cardiac Tamponade↗
PubMed1989

Improved intestinal form and function in diabetic rats fed long-term with a polyunsaturated fatty acid diet.

Short-term (two weeks) feeding of isocaloric diets supplemented with polyunsaturated fatty acids (PUFA) is useful for the prevention or treatment of the enhanced uptake of glucose which occurs in rats with streptozotocin-induced diabetes, as compared with animals fed a diet supplemented with saturated fatty acids (SFA). The study was undertaken to compare the effects of long-term (seven weeks) feeding PUFA or SFA to diabetic rats. We have previously reported that diabetic animals fed PUFA had superior body weight gain, lower hemoglobin AlC values, lower plasma cholesterol and triglyceride levels, lower percentage decline in glucose (K value) following intravenous glucose tolerance testing, near-normal values of hepatic microsomal glucose-6-phosphatase activity and near-normal concentrations of 18:2(6) and 20:4(6) in liver microsomal phosphatidylcholine and phosphatidylserine. However, jejunal and ileal uptake of varying concentrations of glucose were similar in the three diet groups. Thus, the potential long-term beneficial effects of feeding diets with a high PUFA/SFA ratio probably have their explanation in metabolic effects distant to their uptake by the intestine.

Animals↗
PubMed1988

Growth failure in bronchopulmonary dysplasia: elevated metabolic rates and pulmonary mechanics.

Growth failure is a major problem in infants with bronchopulmonary dysplasia (BPD), but the cause is unknown. We studied 13 infants with BPD but without other medical problems that could contribute to growth failure at 6 months' corrected age. We measured resting oxygen consumption (Vo2), Pao2, airway resistance, specific airway conductance, and dynamic pulmonary compliance (Cdyn) by body plethysmography and growth. Growth failure was defined as height and weight less than the tenth percentile of the Babson growth curves. Vo2 in infants with growth failure and BPD was markedly elevated compared with that in control infants and infants with BPD and normal growth. Vo2 showed an inverse correlation with body weight in infants with BPD but not in control infants. Although Vo2 was inversely related to Cdyn, the total work of breathing only partially explained the increased metabolic demands of the growth failure group. We speculate that growth failure in infants with BPD is partially the result of increased metabolic demands from increased work of breathing but that other mechanisms may act to elevate the metabolic expenditure of these infants.

Airway Resistance↗
PubMed1988

Dietary effects of omega 3-fatty acids on intestinal transport function.

Animals were fed for 2 weeks on one of four isocaloric and isocholesterolic semisynthetic diets: high 18:3 omega 3, low 18:3 omega 3, high 20:5 omega 3, or low 20:5 omega 3. The weight of the intestine and the percentage of the wall consisting of mucosa was greater in high 20:5 omega 3 than in high 18:3 omega 3, and greater in low 20:5 omega 3 than in low 18:3 omega 3, although the mucosal surface area was 26% lower in high 20:5 omega 3 than high 18:3 omega 3. The jejunal uptake of 40 mM glucose and ileal uptake of 40 mM galactose was greater in high 18:3 omega 3 than in high 20:5 omega 3, jejunal uptake of fatty acid 12:0 was higher, but 18:0 was lower in high 18:3 omega 3 than in high 20:5 omega 3. The jejunal or ileal uptake of cholesterol was not affected by 20:5 omega 3. However, 20:5 omega 3 had a variable effect on the uptake of medium- and long-chain fatty acids. Alterations in the uptake of fatty acids and glucose were not explained by any difference in the animals' food consumption, body weight gain, or intestinal weight, but the reduced jejunal uptake of 40 mM glucose in rats fed the high 20:5 omega 3 diet was associated with reduced mucosal surface area. Thus, (i) varying the source of omega 3-fatty acids (vegetable, 18:3 omega 3 versus fish oil, 20:5 omega 3) altered the mucosal mass of the intestine, and (ii) the source of the dietary omega 3-fatty acid (18:3 omega 3 versus 20:5 omega 3) influenced intestinal hexose uptake, with fish oil having an anti-absorptive effect on the jejunal uptake of D-glucose.

Animals↗
PubMed1988

Growth failure in infants with bronchopulmonary dysplasia: nutrition and elevated resting metabolic expenditure.

The mechanisms underlying growth failure in infants with bronchopulmonary dysplasia are poorly understood. Thirteen infants with bronchopulmonary dysplasia at 6 months of corrected age and 12 full-term healthy control infants matched for age or size were studied. Resting oxygen consumption was measured during natural sleep, and an estimation of the resting metabolic expenditure by indirect calorimetry was performed. Growth parameters were measured, and a nutritional profile including dietary intake, stool analysis, and serum albumin, cholesterol, glucose, and prealbumin was obtained. Seven of the 13 infants with bronchopulmonary dysplasia had growth failure (defined as length and weight less than the tenth percentile of the Babson growth curves). These infants had lower birth weight, lower gestational age, and a greater number of days spent in supplemental oxygen or on mechanical ventilation. There was no statistical difference between the bronchopulmonary dysplasia-growth failure and bronchopulmonary dysplasia-normal growth infants for dietary intake or stool or serum analyses. However, serum prealbumin showed a significant linear correlation with body weight in infants with bronchopulmonary dysplasia. Resting metabolic expenditure was elevated in infants with bronchopulmonary dysplasia with growth failure and was inversely correlated with body weight in all infants with bronchopulmonary dysplasia. Thus, infants with bronchopulmonary dysplasia and growth failure have increased metabolic demands and decreased prealbumin values suggesting a relative state of protein-calorie malnutrition.

Bronchopulmonary Dysplasia↗
PubMed1988

Clinically unsuspected hypoxia during sleep and feeding in infants with bronchopulmonary dysplasia.

Infants with bronchopulmonary dysplasia have a high incidence of sudden, unexplained death in the postneonatal period; yet the cause of these deaths is unknown. It was hypothesized that infants with bronchopulmonary dysplasia, thought to be well oxygenated based on awake PaO2 values, would have clinically unsuspected arterial oxygen desaturation during sleep and that these would correlate with the severity of pulmonary function abnormalities. The infants studied were 14 with bronchopulmonary dysplasia, 15 who were preterm, had no bronchopulmonary dysplasia, but did have neonatal respiratory distress syndrome, and eight who were full term and used for control at 37 to 45 weeks postconception. Continuous noninvasive monitoring of oxygenation (arterial oxygen saturation [SaO2, pulse oximetry] and transcutaneous oxygen tension was performed during sleep, wakefulness, and feeding. Greater than 80% of each recording was free of artifact for SaO2. Preterm infants with bronchopulmonary dysplasia and respiratory distress syndrome spent greater time at SaO2 less than 90% than control infants. Most desaturations occurred during feeding and to a lesser extent during wakefulness, active sleep, and quiet sleep. Episodes of desaturation (SaO2 less than 90%) lasted 15 to 20 seconds and were not associated with apnea, bradycardia, cyanosis, or changes in transcutaneous PO2. Only infants with bronchopulmonary dysplasia showed severe desaturations (SaO2 less than 80%). Total desaturation in those infants correlated with airway resistance (body pressure plethysmography). Abnormal pneumographic findings did not predict abnormal desaturations. It was concluded that clinically unsuspected oxygen desaturation occurs frequently in preterm infants with and without bronchopulmonary dysplasia, and profound hypoxemia may be responsible for sudden unexplained deaths in these infants.

Bronchopulmonary Dysplasia↗
PubMed1988

Hypoxic arousal responses in infants with bronchopulmonary dysplasia.

Infants with bronchopulmonary dysplasia have a high incidence of sudden, unexplained death in the postneonatal period, yet the cause of these deaths is unknown. Frequent episodes of clinically unsuspected arterial oxygen desaturation have recently been described in infants with bronchopulmonary dysplasia. We hypothesized that infants with bronchopulmonary dysplasia who experience frequent episodes of hypoxia may have abnormal arousal responses to these hypoxic episodes. We studied 12 infants with bronchopulmonary dysplasia at 41.4 +/- 1.3 weeks postconceptional age. Hypoxic arousal responses were performed during quiet sleep at an inspired oxygen tension of 80 mm Hg for a maximum of three minutes or until arousal occurred. Of 12 infants, 11 (92%) aroused normally to the hypoxic challenge. However, all infants required vigorous stimulation and supplemental oxygen after the initial arousal response. Of 12 infants with bronchopulmonary dysplasia, eight (67%) experienced prolonged apnea with bradycardia, and four of 12 (33%) required brief ventilatory assistance (bag and mask) to restore normal breathing. Abnormal pneumographic findings did not predict the occurrence of these prolonged periods of apnea and bradycardia following hypoxia. We conclude that an abnormal response to hypoxia following arousal may lead to prolonged apnea and bradycardia in infants with bronchopulmonary dysplasia. We speculate that the inability to recover from this hypoxia may result in sudden death in these infants.

Arousal↗
PubMed1987

Spectrum of effects of dietary long-chain fatty acids on rat intestinal glucose and lipid uptake.

Isocaloric modification in the ratio of dietary polyunsaturated-to-saturated fatty acids influences intestinal uptake of actively and passively transported nutrients. This study was undertaken to determine which dietary fatty acid was responsible for these alterations in absorption. Adult female rats were fed isocaloric semisynthetic diets high in palmitic and stearic acids (SFA), oleic acid (OA), linoleic acid (LA), or linolenic acid (LNA). An in vitro technique was used to measure the uptake of varying concentrations of glucose as well as a series of fatty acids and cholesterol. Jejunal uptake of 40 mM glucose was highest in rats fed SFA and lowest in those fed LA; ileal glucose uptake was similar in OA, LA, and LNA, but was lowest in SFA. Jejunal uptake of medium-chain fatty acids (8:0-12:0) was higher in OA than in other diet groups; ileal uptake of medium-chain fatty acids was unaffected by diet. Jejunal and ileal uptake of 18:2 was higher in LNA than in SFA or OA; the uptake of the other long-chain saturated or unsaturated fatty acids was unchanged by diet. The ileal but not the jejunal uptake of cholesterol was increased in LA as compared with SFA or OA, and reduced in LNA as compared with LA. These transport changes were not explained by differences in the animals' food consumption, body weight gain, intestinal mass, or mucosal surface area. We postulate that these diet-induced transport alterations may be mediated via changes in brush border membrane phospholipid fatty acyl composition. Thus, intestinal transport of nutrients may be varied by isocaloric changes in the dietary content of individual fatty acids.

Animals↗
PubMed1984

Physiology of a temperature-sensitive mutant of Saccharomyces cerevisiae defective in phosphofructokinase activity.

In this paper, we describe a temperature-sensitive mutant of the yeast Saccharomyces cerevisiae (P5-9) which at a restrictive temperature (36 degrees C) shows a pleiotropic defect for transport of many different metabolites. The temperature sensitivity of the mutant is closely related to a reduction in phosphofructokinase activity. This conclusion is based on the following criteria. (i) Both the primary isolate, designated P5-9 (ts [rho-] Ino-), which is an inositol auxotroph and respiration deficient, and a purified derivative, SB4 (ts [rho+] Ino+ ), which is respiration competent and capable of growing in the absence of inositol, are temperature sensitive for growth and ethanol production in media containing glucose or fructose as the sole carbon source. (ii) The respiration-competent derivative SB4 is not temperature sensitive in media containing glycerol or glycerol-pyruvate; glucose inhibits its growth at 36 degrees C in these media. (iii) Assays of glycolytic enzymes in P5-9 and SB4 extracts, prepared from cells incubated for 1 to 2 h at 36 degrees C before harvesting, show selective reduction in phosphofructokinase activity. Analysis of tetrads derived from the cross of mutant and nonmutant haploids indicates that temperature sensitivity for growth is due to a single gene or to two closely linked genes. The biochemical analysis of spores from seven such tetrads revealed a uniform cosegregation of temperature sensitivity for growth and phosphofructokinase activity. Transport and ATP levels were drastically reduced in SB4 cells incubated at 36 degrees C for 1 to 2 h with glucose as the carbon source, but not when glycerol-pyruvate or lactate was the energy source. Therefore, depletion of energy as a result of phosphofructokinase inactivation appears to be the cause of the pleiotropic transport defect observed in the mutant.

Adenosine Triphosphatases↗
PubMed1980

An evaluation of behavioral techniques reinforced with an anorectic drug in a double-blind weight loss study.

Sixty obese outpatients participated in a double-blind comparison of diethylpropion hydrochloride and placebo in conjunction with a behavior modification program for weight reduction. Assessments of efficacy and program acceptance included total weight loss, percent of initial (baseline) weight loss, percent excess weight lost, effectiveness of overall program, and helpfulness of medication. Diethylpropion was significantly better than placebo in all five assessments. An added behavioral technique, a substantial refundable deposit of money, reduced the attrition rate of all study entrants from 50% to 10%; thus patient compliance was greatly enhanced.

Adult↗