Browsing by Author "Laws, J."

Background: Routine total parenteral nutrition (TPN) in neonatal care can result in hepatic dysfunction in 40–60% of patients, most commonly as fatty liver, but little work has been conducted on the underlying mechanisms causing hepatic dysfunction. Objective: To use a piglet model for the premature human neonate on TPN, supplemented with lipid emulsions, to investigate hepatic responses. Method: Piglets were delivered 2 days prematurely. Six control piglets were fed enterally (E), whilst twelve animals were maintained on TPN. TPN piglets received the standard TPN solution plus the lipid emulsion as either ClinOleic (C, n = 6) or Intralipid (I, n = 6). Hepatic lipid content and the fatty acid composition of liver triacylglyercol (TAG) as well as hepatic lipase (HL) activity were determined. Lipoprotein lipase (LPL) activity was measured in the liver, muscle and adipose tissue. The plasma concentrations of choline, bilirubin, TAG and non-esterified fatty acids (NEFA) were also measured. Results: Liver lipid was significantly increased in piglets on TPN and the tissue fatty acid profiles reflected the lipid emulsion. HL and LPL activities were reduced in liver but LPL increased in adipose tissue during TPN. Plasma concentrations of choline, bilirubin, TAG and NEFA were similar across the treatments. Conclusions: The results suggest fatty liver occurs in neonates receiving TPN and the source of the accumulated lipid appears to be the lipid emulsion used. The factors regulating lipase activity during TPN require further study. The piglet can be used as a model for neonatal TPN.

To study the changes in the thyroid function in diabetic rats, streptozotocin was injected i.p. in rats on a low iodine diet. They were compared with controls which were fed the same diet and injected with medium. The streptozotocin treated animals showed an intense diuresis and hyperglycemia during the 29 days after the treatment. These animals-had a normal plasma 127PBI concentration but reduced uptake of 131 1 by their thyroids and plasma concentration 24 hours after the injection of the tracer. The rats treated with streptozotocin showed an increased content of 1271 in their thyroids and an altered distribution of the percentages of radioactive iodoaminoacids, with an augmented proportion of DIT and reduced concentrations of T4 and T3 • These results suggest that the synthesis and release of thyroid hormones are reduced in the diabetic animals. This decreased thyroid function agrees with the reduced hormonal effectiveness of TSH described by other authors.