Biomedical subjects

R J Shulman

Publications and source records attributed to R J Shulman.

81 records · Page 5Linked to original sources

PubMedDate not supplied

Total parenteral nutrition-related cholestasis in infants.

An epidemiological study was conducted to estimate the proportion of infants on total parenteral nutrition (TPN) who developed cholestasis and to identify risk factors associated with the development of this disease. Data were abstracted from medical records of 624 infants less than or equal to 30 days of age who were treated with TPN. A case of TPN-related cholestasis was defined as an infant whose serum level of direct bilirubin was greater than or equal to 1.5 mg/dl subsequent to initiation of TPN. Risk factors were assessed using multiple logistic regression analysis. Forty-six of 624 infants in the cohort (7.4%) were classified as having TPN-related cholestasis. The multivariable analysis indicated that cholestasis was associated with intracranial hemorrhage, patent ductus arteriosus, sepsis and gastrointestinal conditions that require surgery. Two distinct processes appear to have occurred: in infants who experienced patent ductus arteriosus or intracranial hemorrhage (conditions associated with hypoxia) where TPN may be the necessary trigger for the development of cholestasis, and in infants with gastrointestinal conditions requiring surgery or sepsis, where cholestasis may develop with or without parenteral infusions.

Birth Weight↗

PubMedDate not supplied

Liver composition and histology in growing infant miniature pigs given different total parenteral nutrition fuel mixes.

Although young infants are at greater risk for total parenteral nutrition (TPN)-related liver disease than adults, previous studies on the effect of the TPN energy source on the development of hepatic steatosis have been carried out in adult rats and adult humans. We studied the effect of a glucose and a glucose/fat TPN energy regimen on hepatic chemical composition and the development of steatosis in newborn miniature pigs. Twenty miniature pigs were randomized at 10 days of age to receive a TPN regimen which utilized either glucose (group A) or glucose/fat (group B) as the non-nitrogen energy source. After 8 days, blood was drawn for insulin, glucagon, SGPT, albumin, and bilirubin determinations. Samples of liver were obtained at 9 days. Plasma insulin levels were significantly higher and glucagon levels lower in group A piglets than in those in group B. Normal values were obtained for SGPT, albumin, and bilirubin, and no differences were found between groups. Chemical analysis of the livers revealed no differences between groups in the concentrations of glycogen, fat, protein, DNA, and RNA. Group A animals had significantly higher concentrations of water than group B (group A: 0.75 +/- 0.01 liter/kg; group B: 0.74 +/- 0.01; p less than 0.03). A significant correlation was found in group B between the plasma insulin/glucagon ratio and the hepatic glycogen concentration (r = 0.73, p less than 0.05). Group A animals had fat vacuoles in centrilobular hepatocytes, in contrast with group B animals who had visible fat only in Kupffer cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Use of hydrochloric acid to clear obstructed central venous catheters.

Central venous catheters are being used with increasing frequency to administer drugs, and as a result, catheter obstruction caused by precipitation of poorly soluble fluid components has become a common problem. We report our first experience using 0.1 N hydrochloric acid to restore patency to central venous catheters obstructed from insolubility-induced precipitation. Precipitation was caused by drug as well as calcium and phosphorus incompatibilities. The initial use of urokinase in two cases was unsuccessful in restoring catheter patency. In all four cases, the instillation of 0.2-1.0 ml of HCl cleared the catheters. Catheter patency usually was gained immediately. No side effects were noted. Our experience supports preliminary data (JPEN 9 (suppl):255, 1985) which suggest that 0.1 N HCl is effective in clearing insolubility-induced precipitation in central venous catheters.

Acetates↗

PubMedDate not supplied

Glutamine or glutamic acid effects on intestinal growth and disaccharidase activity in infant piglets receiving total parenteral nutrition.

This study was designed to measure the effect of free glutamine or glutamic acid supplementation on small intestinal growth and disaccharidase enzyme activity in 7-day-old miniature piglets. The piglets received one of three total parenteral nutrition solutions exclusively for 7 days. All three solutions were isonitrogenous and isocaloric, and glutamine or glutamic acid was included at physiological levels (5% of the total amino acid content) in two of the three solutions; the third (control) contained neither glutamine nor glutamic acid. No differences were seen between groups in plasma glutamine or glutamic acid concentrations. Similarly, no effect was observed on small intestinal protein or DNA content or on the specific activities of lactase, sucrase, or maltase. These data demonstrate that in the healthy miniature piglet, parenteral glutamine or glutamic acid supplemented at physiological doses does not influence small intestinal growth and development.

Animals↗

PubMedDate not supplied

Total parenteral nutrition energy composition affects small intestinal disaccharidase activity in the newborn miniature pig.

Total parenteral nutrition (TPN) decreases disaccharidase activity in the small intestine of humans and miniature piglets. The possibility, however, that specific components of TPN (eg, the energy mix) will increase disaccharidase activity has largely been unexplored. The identification of such components would be particularly useful in the treatment of premature infants with immature gastrointestinal tracts and patients with small intestinal mucosal disease associated with decreased disaccharidase activity. To determine whether the TPN energy composition affects small intestinal disaccharidase activity, 7-day-old miniature piglet littermates were randomized to receive TPN containing either glucose (group G) or glucose and fat (group G/F) as the nonnitrogen energy source(s). The TPN regimens were isonitrogenous and isoenergetic. The piglets were not allowed oral intake during the 7 days they were maintained on TPN. At 14 days of age the piglets were killed and the small intestines analyzed for weight, protein, DNA, and disaccharidase activity. Body weight was similar between groups at both the beginning and end of the study. The TPN regimen did not affect small intestinal weight of protein and DNA content. However, jejunal and ileal sucrase and ileal maltase activities (mumol/min.kg body wt +/- SD) were greater in group G than those in group G/F (28 +/- 9 vs 19 +/- 11, p = 0.04; 13 +/- 7 vs 7 +/- 4, p = 0.037; and 31 +/- 8 vs 19 +/- 10, p = 0.0088, respectively). No differences in lactase activity were noted between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Volume of blood required to obtain central venous catheter blood cultures in infants and children.

To determine how much blood must be discarded before one can obtain a reliable central venous catheter blood culture, we prospectively cultured the blood (from 96 patients) that is ordinarily discarded before obtaining blood for such a culture. We then compared the prospective culture results with those of the actual blood culture. Three sequentially drawn aliquots of blood were aspirated from the central venous catheter and cultured. The culture results of the second aliquot were comparable to those of the third (the portion usually cultured) in overall sensitivity (94.4%), specificity (94.9%), and positive predictive value (80.9%). Thus, the amount of blood that must be discarded (infants: 0.3 mL; children: 1.0 mL) before one can obtain an accurate central venous catheter culture is less than was previously thought.

Bacteremia↗

PubMedDate not supplied

Supplemental alanylglutamine, organ growth, and nitrogen metabolism in neonatal pigs fed by total parenteral nutrition.

The objective of this study was to determine whether supplemental glutamine (alanylglutamine dipeptide) is effective in preventing small intestinal mucosal atrophy associated with total parenteral nutrition and whether it affects the growth of other organs in neonatal pigs. We compared organ growth, intestinal enzyme activity, and plasma nitrogen metabolites in 4-day-old pigs randomly selected to receive total parenteral nutrition supplemented with 0 g, 2.0 g, or 4.5 g of glutamine per deciliter for a total amino acid intake of either 11 or 25 g.kg-1.d-1 for 7 days. Glutamine supplementation increased (60% to 100%) plasma concentrations of glutamine, urea nitrogen, ammonia, and both jejunal villus height and surface area, but it did not significantly affect jejunal mucosal protein and DNA masses or the relative growth of liver, kidneys, and brain. No histologic evidence of tissue toxicity was found. Supplementing large amounts of glutamine (alanylglutamine dipeptide) did not completely prevent total parenteral nutrition-associated intestinal mucosal atrophy but did improve villus morphology without affecting vital organ growth or histology.

Amino Acids↗

PubMedDate not supplied

Does the use of hydrochloric acid damage silicone rubber central venous catheters?

BACKGROUND: Hydrochloric acid (HCl) is commonly used to clear obstructions in central venous catheters (CVC). METHODS: To determine if HCl adversely affects the integrity of a CVC we infused 0.1 N HCl daily into CVC in vitro. At weekly intervals sections of the CVC were removed and examined using scanning electron microscopy. RESULTS: Over 8 weeks, no damage to the CVC was visible. CONCLUSIONS: HCl administration poses no threat to the structural integrity of a CVC.

Catheterization, Central Venous↗

PubMedDate not supplied

Central venous catheters versus peripheral veins for sampling blood levels of commonly used drugs.

BACKGROUND: Our objective was to compare the accuracy of drug levels in blood samples obtained from central venous catheters with those from peripheral blood samples taken to monitor various drug levels. METHODS: Pediatric patients with central venous catheters receiving aminoglycosides, vancomycin, or cyclosporine had central and peripheral blood samples obtained within 5 minutes of each other and analyzed simultaneously. We ascertained how well blood levels from central venous catheters compared with those from peripheral blood (the criterion standard). RESULTS: There were no clinically significant differences between central and peripheral values for amikacin, gentamicin, tobramycin, and vancomycin (both peaks and troughs). Preliminary data indicated that oral cyclosporine can be monitored via central venous catheter. In contrast, there was poor agreement between peripheral and central values when cyclosporine was administered by IV. CONCLUSIONS: Amikacin, gentamicin, tobramycin, vancomycin, and probably oral cyclosporine can be monitored accurately via central venous catheter. In contrast, IV cyclosporine should be monitored via peripheral blood.

Adolescent↗