ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Measurement of 4-methylumbelliferylp-guanidinobenzoate (MUGB)-hydrolyzing activity in the plasma of normal controls, cystic fibrosis (CF) heterozygotes, and CF homozygotes did not support previously reported (35) differences in MUGB-hydrolyzing activity. We identified human plasma albumin as the major source of MUGB-hydrolyzing activity by comparison of our plasma results to those obtained with physiologic concentrations of commercial albumin samples. Substantiating evidence was obtained from gel filtration experiments and correlation of albumin levels in CF plasma with MUGB titers. We found essentially no proteolytic activity towards dinitrophenylprotamine sulfate associated with commercial albumin samples. It appears that the reaction between human albumin and MUGB represents a weak esterase activity, perhaps involving the acylation of a specific site(s) on the protein.Hypoalbuminemia has been documented (8) in some CF patients. Low albumin concentrations, indicated by MUGB titers < 190 nmole methylumbelliferone/ml plasma, were found in 42%.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Electron spin resonance (ESR) and the spin label method, with 5-doxyl stearic acid as a probe, were used to investigate the structure of microvillus membrane (MVM) from small intestine of adult and newborn rats. It was shown that the spin label in MVM of newborn was maintained in a more disordered environment than the spin label in adult animals. Calcium ion was used as an external stimulus to study the structural response and organization of these two membrane preparations. Ca++enhanced the order of 5-doxyl stearic acid labeled MVM from mature and immature rats in a concentration-dependent saturable process, but Ca++exerted a greater ordering effect on MVM from immature than MVM from the mature rat. Ca++binding to MVM was also a concentration-dependent, saturable process. MVM from immature rat bound significantly more Ca++in CaCl2concentration ranges from 12.5 μm to 4mM. Scatchard analysis of the binding data showed two classes of binding sites with a high affinity constant of 3.1 ± 104M-1and a low affinity constant of 9.1 ± 103M-1, with corresponding maximum binding capacities for each class site of 129.8 nmole of calcium/mg protein and 252.7 nmole calcium/mg of protein in newborn and 13-day-old MVM. Only one high affinity constant of 2.6 ± 104M-1with a corresponding maximum binding capacity of 106.4 nmole/mg of protein was observed in adult MVM. Proteolytic hydrolysis of the membranes by trypsin produced an increase in Ca++binding in adult MVM and a decrease in Ca++binding in newborn MVM. Neuraminidase and phospholipase C reduced the amount of bound Ca++in both adult and newborn MVM. These results indicate a more disordered structure of newborn MVM and a differential effect of Ca++on MVM during development.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The course of development of hypocortisolism was studied in 20 patients with autoimmune polyendocrinopathy-candidosis-ectodermal dystrophy (APECED) for 1.3–9.3 years during which time the patients underwent at least three 2-h ACTH tests (2hAT). A slow progression of the disease was evident and could be staged. The earliest indicators of incipient failure were sub-normality of the 2-h cortisol level alone or with subnormality of the 2-h increment. The increment was then abolished. A normal basal level was maintained longer. Longer forms of the ACTH tests produced normal responses even after the early stages of failure. A constantly elevated ACTH concentration and low cortisol/ACTH ratio in plasma were likewise signs of advanced hypocortisolism. Current criteria of primary hypocortisolism are thus indicators of the late stages of failure only. The presence of circulating adrenocortical antibodies is predictive of hypocortisolism. Some patients had normal 2hAT responses, but antibodies and subnormal cortisol/ACTH ratios. This may represent a state of compensatory activation of the hypothalamic-pituitary-adrenocortical axis.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The ability of rotavirus-infected cells to stimulate leukocytes to release a cytokine which enhanced the subsequent leukocyte cytotoxicity to a second set of [5lCr] labeled rotavirus-infected cells was analyzed. Human interferon increased leukocyte cytotoxicity to Simian rotavirus (SA-11)-infected target cells. Similarly, 11 of 12 supernates of SA-11-stimulated peripheral blood leukocyte cultures increased the killing of SA-11-infected cells (P< 0.005). This resulted in a calculated cytokine-dependent cellular cytotoxicity value of 9.6 ± 1.9%. Three of five of the supernates tested contained measurable levels of interferon (12–48 unit/ml). In contrast, SA-11-stimulated colostral leukocyte culture supernates neither increased leukocyte cytotoxicity nor contained measurable levels of interferon.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

In an effort to understand the temporal organization of infant physiologic and behavioral systems during social interaction with adults, spectral and cross-spectral analyses of infant heart rate and mother-father-stranger-infant behavioral data are described herein for a 3-month-old infant during face-to-face social interaction with her parents and a stranger. This infant's heart rate rhythms were stronger during social interaction with both mother and father than with a stranger. Infant behavioral rhythms were associated with (high coherence) the parents' behavioral rhythms, but not with those of the stranger. Furthermore, infant heart rate and infant behavioral rhythms showed high coherence with all three adults. Although these findings are preliminary, based on a case study and need replication, they generate intriguing hypotheses. This technique of studying the rhythmicity of infant social interaction with spectral analysis suggests that the 3-month-old infant's behavior and heart rate are synchronized during interaction with all three adults; however, the infant and adult behavioral rhythms are synchronous only with mother and father and not with an unfamiliar stranger.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Three children in two families presented in early childhood with episodes of illness associated with fasting which resembled Reye's syndrome: coma, hypoglycemia, hyperammonemia, and fatty liver. One child died with cerebral edema during an episode. Clinical studies revealed an absence of ketosis on fasting (plasma beta-hydroxybutyrate < 0.4 mmole/liter) despite elevated levels of free fatty acids (2.6–4.2 mmole/liter) which suggested that hepatic fatty acid oxidation was impaired. Urinary dicarboxylic acids were elevated during illness or fasting. Total carnitine levels were low in plasma (18–25 μmole/liter), liver (200–500 nmole/ g), and muscle (500–800 nmole/g); however, treatment with L-carnitine failed to correct the defect in ketogenesis. Studies on ketone production from fatty acid substrates by liver tissuein vitroshowed normal rates from short-chain fatty acids, but very low rates from all medium and long-chain fatty acid substrates. These results suggested that the defect was in the mid-portion of the intramitochondrial beta-oxidation pathway at the medium- chain acyl-CoA dehydrogenase step. A new assay for the electron transfer flavoprotein-linked acyl-CoA dehydrogenases was used to test this hypothesis. This assay follows the decrease in electron transfer flavoprotein fluorescence as it is reduced by acyl-CoA-acyl-CoA dehydrogenase complex. Results with octanoyl-CoA as substrate indicated that patients had less than 2.5% normal activity of medium-chain acyl-CoA dehydrogenase. The activities of short-chain and isovaleryl acyl-CoA dehydrogenases were normal; the activity of long-chain acyl-CoA dehydrogenase was one-third normal.These results define a previously unrecognized inherited metabolic disorder of fatty acid oxidation due to deficiency of medium-chain acyl-CoA dehydrogenase. The carnitine deficiency in these patients appears to be a secondary consequence of their defect in fatty acid oxidation. It is possible that other patients with “systemic carnitine deficiency,” who fail to respond to carnitine therapy, may also have defects in fatty acid oxidation similar to medium-chain acyl-CoA dehydrogenase deficiency.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

We reexamined a previously reported, highly specific increase in the relative proportion of the mitochondrial isoenzyme of asparate aminotransferase (AST) in the serum of patients with Reye's Syndrome. Using ion exchange chromatography, we measured mitochondrial, cytosolic, and total AST in serum samples from (1) 10 patients early in the course of Reye's Syndrome; (2) nine controls with normal serum AST; and (3) seven controls with other diseases causing an increase in serum AST. The mitochondrial percentage (2.8 ± 2.0%) in Reye's Syndrome was significantly lower (P< 0.05) than that of both the normal control group (6.1 ± 7.1%) and the group with increased AST (5.6 ± 4.0%). We thus failed to confirm the previous report of a specific increase in the % of mitochondrial isoenzyme in Reye's Syndrome, and conclude that the % of mitochondrial isoenzyme is not likely to be a useful marker of (or predictor for progression to) Reye's Syndrome.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

We examined the effect of phototherapy on cutaneous bilirubin using the transcutaneous bilirubinometer (TcB) in 14 white infants at a mean postnatal age of 30 h. Six infants were treated with blue light, eight with white light. An opaque patch, 2.5 cm in diameter, covered the skin and served as a source for TcB control values. Simultaneous TcB measurements were obtained from exposed and patched areas every 15 min during 4 h of phototherapy.After the start of phototherapy, TcB index obtained from patched skin did not change during the course of treatment. Data from exposed skin showed that the initial rate of TcB index fall during the first hour was significantly faster than the successive values during the next 3 h in both groups studied. During the first 2 h of therapy the TcB index decreased faster among infants treated with blue light.Correlation studies indicate that TcB measurements from exposed skin areas may not be clinically useful in predicting serum bilirubin response to phototherapy but data obtained from unexposed sites may fill this role.

ISSN:0031-3998    

出版商:OVID    

年代:1983

数据来源: OVID