Biomedical subjects
J Bhatia
Publications and source records attributed to J Bhatia.
Parenteral nutrition in the neonate.
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Comfort/palliative care guidelines for neonatal practice: development and implementation in an academic medical center.
OBJECTIVE: To report the multidisciplinary developmental process of a comfort care guideline for the neonatal intensive care unit (NICU) addressing palliative care measures in a tertiary academic medical center. The guideline was developed to be (1) practical, (2) family-centered, (3) respectful of the infant patient, and (4) educational. METHODS: A consensus-building process involving medical, nursing, administrative, and ancillary professional staff integral to the NICU and Obstetrics units using naturalistic inquiry. RESULTS: An approved hospital guideline was formulated and implemented over a 16-month period. It described candidates for comfort care, the locale for such care to be rendered, and the construct of essential services to the infant and family. Early reports attest to staff acceptance and it is currently incorporated into trainee education. CONCLUSION: Clinically practical guidelines, comprehensive in their scope of providing comfort care to newborns with life-limiting conditions, can be institutionally derived and locally implemented for both consistency in patient care and educational value for staff and trainees.
Riboflavin enhances photo-oxidation of amino acids under simulated clinical conditions.
In neonatal nurseries, solutions of amino acids with added vitamins may be exposed to relatively intense light from phototherapy units. Light, especially in the presence of photosensitizers such as certain vitamins, is capable of destroying amino acids. In the present study, the effect of riboflavin on amino acid concentrations in solutions exposed to light was studied. Solutions of crystalline amino acids with and without added riboflavin were infused into shielded collecting vessels for 24 hr under conditions simulating those occurring during phototherapy. Decreases in concentrations of some amino acids were observed with light exposure alone. Decreases in concentrations of methionine, proline, tryptophan, and tyrosine were significantly greater in the presence of riboflavin that in its absence. Riboflavin concentrations were also significantly reduced after light exposure. Although the losses of amino acids are probably not nutritionally significant, the photo-oxidation products are largely unknown and may be toxic.
Photosensitized oxidation of tryptophan and hepatic dysfunction in neonatal gerbils.
Hepatic dysfunction is a common metabolic complication of parenteral nutrition. Studies in animals have suggested that several amino acids, especially tryptophan, may play a role in the development of hepatic dysfunction. Further, photoirradiation of amino acids in the presence of photosensitizers, such as riboflavin, causes photooxidative changes in several amino acids. The present study was undertaken to determine the effect of tryptophan, after photoirradiation in the presence of riboflavin, on hepatic function in neonatal gerbils. Two-week-old suckling gerbils received approximately 4 mmol/kg/day of light-exposed or nonlight-exposed tryptophan or received saline intraperitoneally for 4 days. An increase in the activity of serum gamma-glutamyl transpeptidase was found in gerbils receiving both light-exposed and nonlight-exposed tryptophan compared to control. Concentrations of tryptophan were significantly higher in animals receiving saline than in the other two groups. There were no significant differences in the major tissue amino acids among the three groups of animals. Our data suggest the role of photosensitized oxidation of tryptophan in the pathogenesis of hepatic dysfunction in neonatal gerbils. It is possible that similar photooxidation occurring during infusion of parenteral amino acid solutions containing vitamins exposed to constant illumination in the newborn nursery is responsible for the observed hepatic dysfunction in parenterally fed neonates.
Two cannula method for parenteral infusion and serial blood sampling in the freely moving rat.
Materials and techniques are described for positioning and exteriorizing two chronic venous cannulas in the rat. A cannula for fluid infusion is placed in the inferior vena cava via the femoral vein and exteriorized on the tail, whereas a cannula for blood withdrawal is placed in the superior vena cava and exteriorized in the scapular region. Grooming behavior and range of motion are not impeded since the cannula used for chronic infusion is shielded by a light-weight tail cover instead of a torso harness. Application of this method can minimize numbers of rats used in total parenteral nutrition (TPN) studies as demonstrated by our feasibility study in which serum parameters of liver function were serially monitored in toxin-treated rats infused with nutrient mixtures.
In vivo biliary function in the adult rat: the effect of parenteral glucose and amino acids.
Parenteral glucose and glucose-amino acid mixtures are used in the nutritional support of infants, children, and adults when enteral feedings are precluded for any reason. During the first week of such nutritional support, the total energy intakes are generally low and glucose and electrolytes are the only nutrients provided. To assess the effects of such "hypocaloric" regimens, we determined the hepatic responses to parenteral infusions of either glucose or glucose-amino acid mixtures in rats. Further, to illustrate the magnitude of these changes in comparison to normally fed animals, we included a group of sham-operated, chow-fed rats. Bile flow, biliary bile acid output, bile osmolarity, serum bile acids, and plasma amino acids were measured in adult rats following 5 days of the respective dietary regimens. Liver histology was also assessed. Bile acid output, but not bile flow, was significantly decreased by the infusion of glucose compared to glucose-amino acid mixtures. However, in comparison to the chow-fed rats, bile acid output was significantly reduced in both groups of parenterally fed animals, whereas bile flow was significantly reduced only in the glucose-infused animals. Plasma amino acids were markedly different between the groups; concentrations of essential amino acids were greater in the glucose-amino acid infused animals than in the glucose infused animals. Nonessential gluconeogenic amino acids were significantly higher in the glucose-infused animals compared to the other groups; plasma valine was significantly lower in the glucose-infused animals reflecting the lack of protein intake. Liver histology was markedly abnormal in all of the glucose-infused animals, whereas only half the glucose-amino acid infused animals had abnormal pathology.(ABSTRACT TRUNCATED AT 250 WORDS)
Photosensitized oxidation of tryptophan: effect on liver and brain tryptophan.
Toxic products are formed when tryptophan is irradiated with light in the presence of photosensitizers such as riboflavin. In order to further investigate this phenomenon, solutions of tryptophan (48 mumol.mL-1) were irradiated with broad spectrum fluorescent light in the presence or absence of riboflavin (0.01 mg.mL-1). Solutions of riboflavin were similarly irradiated; control solutions were the respective solutions not exposed to light. Two-week-old suckling gerbils were then assigned to receiving 7 days of intraperitoneal injections of the light-exposed or non-light-exposed solutions. There were significant differences in the concentrations of tryptophan in serum, liver, and brain; activity of gamma-glutamyl transferase (GGT) as well as liver protein were also significantly different among the groups. Body and liver weights were also significantly different among the groups. In order to identify the photoproducts responsible for these changes, solutions of tryptophan that had been irradiated with light in the presence of riboflavin were then fractionated based on time of elution during high-pressure liquid chromatography and the fractions were then injected into the gerbils as before. GGT responses to one of the fractions was similar to that of the parent compound. Chromatographic studies indicated the presence of numerous photoadduct compounds of tryptophan and riboflavin after exposure to light. Both the presence of riboflavin and the exposure of the solutions to light alter brain concentrations of tryptophan in the developing gerbil indicating differing availability to the brain of this serotonin precursor. Clinical implications of the infusion of amino acids in the presence of photosensitizers and light must be considered.
The effects of light exposure on the in vitro hepatic response to an amino acid-vitamin solution.
BACKGROUND: Administration of parenteral nutrition (PN) that has been irradiated with light is associated with hepatic dysfunction in rats in vivo. Using the isolated perfused rat liver, we report the in vitro hepatic response to a light-exposed amino acid-vitamin (AAV) solution, compared with a light-protected solution. METHODS: The amino acid-vitamin solution (3 g Aminosyn and 2.5 mL MVI-12 added to buffer) was placed under a lamp in a beaker that was covered completely with foil (light-protected) or with a transparent wrap (light-exposed) for 24 hours before liver perfusion. Livers from adult male rats were isolated and perfused with buffer for 30 minutes, with the AAV solution for 60 minutes, and again with buffer for 30 minutes. RESULTS: Infusion with the AAV solution resulted in decreases in bile flow rates. Compared with light-protected groups, light-exposure was associated with significantly lower bile flow rates, significant increases in biliary concentrations of oxidized glutathione (GSSG), and significantly decreased biliary concentrations of free amino acids, including the glutathione precursors glutamate and glycine. CONCLUSIONS: Perfusion of the isolated rat liver with an AAV solution that has been irradiated with light for 24 hours results in a decrease in bile flow rates and an increase in biliary GSSG concentrations, suggesting oxidant stress. Consideration should be given to protecting solutions from light in the clinical setting.
Amino acid responses to dietary intake in the first 72 hours of life.
Plasma free amino acid concentrations were measured in cord blood and at 24, 48, and 72h of age in term infants who were either breastfed or fed a whey- or casein-predominant standard term-infant formula. There was a significant initial decrease in the concentrations of almost all amino acids compared with cord blood. Statistically significant effects of the type of feeding were observed in the concentrations of methionine, cystine, tyrosine, alanine, and p-serine; similarly, significant effects of postnatal age were noted in the concentrations of all amino acids with the exception of cystine. These data suggest that the metabolic milieu changes rapidly after delivery, influenced both by postnatal age and by type of feeding. Cord blood urea and histidine concentrations were significantly higher in female infants than in male infants; the route of delivery (cesarean section v vaginal delivery) affected only cord blood concentrations of alanine (vaginal greater than C-section). These data suggest that amino acid responses to the quality of dietary protein observed in infancy (for example, high tyrosine concentrations in response to feeding a casein-predominant formula) develop in the immediate postnatal period.
Hemidiaphragmatic paralysis as a complication of central venous catheterization in a neonate.
Central venous catheter placement has become commonplace in the care of the premature infant because of the need for long-term venous access. Although generally considered safe, there have been numerous reports of complications from the use of these catheters. We report the case of an infant in whom right hemidiaphragmatic paralysis developed after extravasation of fluid from a central venous catheter. The case emphasizes the need for continued vigilance of central venous catheter location and function.