摘要:

SummaryPhototherapy results in the conversion of bilirubin to more water-soluble isomers. Six clinically used phototherapy lamps which differ in their emission spectra have been compared in their ability to produce configurational and structural isomers of bilirubin in vitro. For all of the lamps, the initial rate of configurational isomerization was highly correlated (r=0.969) with the intensity of irradiation falling within the bilirubin absorption band. The percentage of the total bilirubin converted to the configurational isomer at equilibrium was dependent upon the spectral distribution of the lamp, and was greatest (26.2 ± 1.3%) with the special blue lamp, which has a narrow spectral output centered at 445 nm. The rate of formation of the structural isomer, lumirubin, was generally dependent upon the intensity of irradiation within the bilirubin absorption band.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryA 17-year-old boy presented with growth retardation, marked hepatomegaly, and sexual infantilism. Elevated fasting serum insulin levels and a blunted hypoglycemic response to exogenous insulin (up to 0.35 unit/kg) demonstrated severe insulin resistance. Neither anti-insulin nor anti-insulin receptor antibodies were present. The molecular size of his circulating insulin and its binding to IM-9 lymphocytes was normal. Despite high circulating insulin values, both erythrocytes and cultured skin fibroblasts showed normal insulin binding capacity and affinity. Tissue responsiveness was examined by measuring the insulin-induced increase in 2-deoxyglucose uptake into fibroblasts. Although the basal glucose transport rate was slightly lower than that of controls, the insulin-induced increase was normal. However, the normal increase in thymidine incorporation in response to insulin was blunted, as were the thymidine incorporation responses to epidermal growth factor and fibroblast growth factor. These studies demonstrate the possible existence of a new form of postinsulin receptor defect as a cause of insulin resistance, but underscore the difficulty that exists in defining the exact nature of the defect in these disorders.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryA son of related Turkish parents had grossly elevated serum tyrosine concentration and excreted tyrosine and p-hydroxyphenolic acids into the urine, whereas neither succinylacetone nor succinylacetoacetate could be demonstrated. The tyrosine concentration was normalized by a proper diet. This was not followed strictly at home. During the first 2 years of life, the patient had severe undulating nystagmus that disappeared later. No skin lesions were present and there was only slight corneal clouding of the eyes. At the age of 5, the patient had attained the maturity of a 4-year-old, showing a balanced profile.Specific tyrosine aminotransferase (EC 2.6.1.5) was present in the liver; the Kmvalue for tyrosine was normal. However, the total activity was less than 10% of normal, a situation similar to that observed in fetal human liver. A younger sister of the patient also has tyrosinemia and low hepatic tyrosine aminotransferase activity.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

SummaryThis study assessed the tissue reserves of carnitine at birth in a group of neonates (n=22) of varying gestational age dying within 24 h of birth, prior to possible changes in carnitine status induced by postnatal intervention. Tissue carnitine concentration was highest in the muscle in each infant. The mean (±SD) muscle carnitine concentration of 8.4 ± 3.6 nmol/mg noncollagen protein (NCP) in very immature infants (≥1000 g birth weight) was significantly lower than the corresponding mean (±SD) values of 14.0 ± 3.2 nmol/mg NCP in larger preterm infants (1001-2500 g; P<0.01) and 19.4 ± 2.6 nmol/mg NCP in term infants (≤2501 g; P<0.001). Muscle carnitine concentration correlated positively with gestational age (r=0.832; P<0.001) and with body dimensions. Liver and heart carnitine concentrations did not correlate significantly with gestation or body dimensions. The mean (±SD) liver carnitine concentration for all the neonates as a group was 4.1 ± 1.5 nmol/mg NCP. The mean (±SD) heart carnitine concentration was 4.7 ± 1.3 nmol/mg NCP.In comparison to adult controls, tissue carnitine concentrations were markedly lower in neonates, particularly in immature newborns. These data suggest that newborn infants, especially premature babies, are born with limited tissue reserves of carnitine and are therefore at an increased risk for developing carnitine deficiency and its adverse effects in the postnatal period, particularly if maintained on carnitine-free intravenous nutrition for prolonged periods of time.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID