摘要:

ExtractThe activities of key gluconeogenic enzymes in the livers of newborn guinea pigs were monitored as a function of time following birth either vaginally at term or prematurely by cesarian section at 62 days of gestation. The activity of hepatic glucose-6-phosphatase rose dramatically from 1.40 ± 0.26 μmol/min/g at birth to a maximum of 6.8 ± .0.9 μmol/min/g at 24 hr in prematurely delivered animals although there was little significant change in activity in full term animals. The activity of hepatic fructose-1,6− diphosphatase and mitochondrial phosphoenolpyruvate carboxykinase changed little over the first 3 days of life in either full term or premature animals. Cytosolic phosphoenolpyruvate carboxykinase, on the other hand, had low activity at birth being 0.11 ± 0.03 μmol/min/g in full term and 0.06 ± 0.04 μmol in premature animals rising to values of 0.71 ± 0.06 and 1.12 ± 0.12 μmol/min/g, respectively, at 24 hr of life. Pyruvate carboxylase activities in the premature animals remained significantly lower than those in full term animals in the first 72 hr of life. Transient hypoglycemia was evident in the prematurely delivered animals, but not in the full term animals, the blood glucose values being 82 ± 7 mg/100 ml for the full term animals and 20 ± 8 mg/100 ml for the premature infants at 2 hr of life.SpeculationPremature delivery of the newborn guinea pig leads to neonatal hypoglycemia which is due to a combination of deficient hepatic glycogen and compromised gluconeogenic enzyme activity.

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

ExtractThe purpose of this study was to determine the interrelationship of the rise and fall of 2,3-diphosphoglycerate (DPG) with the increase in adult hemoglobin and the decrease in red cell oxygen hemoglobin affinity after birth in normal lambs. It was found that the mean maximum DPG level was 26.71 ± 4.98 mol/g Hb at 7.5 ± 1.1 days. At the same time the mean P50and adult hemoglobin level was 27.0 ± 1.4 mm Hg and 31.1 ± 11.1%, respectively. In the individual lambs, the level of their maximum DPG correlated inversely with the amount of adult hemoglobin (r– 0.77,P< 0.05). Once the DPG began to decrease, there was an inverse correlation between the DPG and the adult hemoglobin present in the red cell (r= 0.68,P< 0.001). It appeared that the rise in DPG postanatally is only a compensatory mechanism until an adequate amount of adult hemoglobin is present. This fact was borne out by the second part of the study in which exchange transfusions with adult red cells were performed on five newborn lambs during the first 24 hr after birth and aborted the rise in DPG.SpeculationThe adaptation from thein uteroto the extrauterine environment requires a rapid reduction in red cell oxygen affinity. The decrease in oxygen affinity is achieved by a transitory postnatal increase in intraerythrocyte DPG.

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

ExtractStudies of a mentally retarded boy, clinically suffering from nonketotic hyperglycinemia, are reported. Using combined gas chromatography-mass spectrometry, enzyme specificity studies, and spectropolariometry D-glyceric acid in extremely elevated concentrations was demonstrated in both serum and urine (serum: 1.0–1.3 mmol/liter, urine: 33–187 mmol/liter). Hydroxypyruvic acid was not detectable in urine from this boy using a gas chromatographic method with a limit of detection of 0.3 mmol/liter. Enzyme assays of D-glyceric dehydrogenase on blood leukocytes demonstrated significantly lower activity in the patient compared with five normal children.SpeculationThe accumulation of glycine in this new metabolic defect may result from a secondary inhibition of the glycine cleavage system, an explanation that would correspond well with the current concept on the genesis of the glycine accumulation found in ketotic hyperglycinemia.

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

ExtractLiver from normal Wistar rats was grafted into the liver of homozygous Gunn rats which are deficient in UDP glucuronyl transferase (UDPGT) (bilirubin) activity. After 3 months, UDPGT activity (bilirubin) remained absent in microsomal suspensions of liver from recipient rats and no bilirubin glucuronide was detected in their bile.SpeculationWe were unable to confirm previous reports suggesting that transplantation of segments of normal rat liver into Gunn rat liver resulted in amelioration of jaundice because of UDPGT activity in the recipient liver.

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

ExtractBlood sugar and plasma free fatty acids (FFA), immunoreactive insulin (IRI), and growth hormone (GH) responses to a protein-glucose meal were determined in normal infants and those with marasmus and marasmic kwashiorkor. Among the normal subjects, fasting blood sugar (BS), peak BS and IRI, and the IRI/BS ratio tended to decrease as age increased. Peak IRI was at least 13 μU/ ml above fasting in 21 of 24 infants. Fasting GH levels were high, 38.5 ± 13.6 (SD) and 26.3 ± 14.0 ng/ml, in the two youngest groups (under 1 year) and were comparable with those of the late newborn period. They were slightly lower, 20.8 ± 22.1, in those 12.5–18.5 months of age. Suppressions of FFA and subsequent rebounds were in close temporal relation to BS and IRI peaks and lows, but not the GH levels. GH was promptly suppressed by the meal, and in most infants secondary elevations were seen.Untreated marasmic infants had normal or low BS, correspondingly normal or low IRI, markedly elevated FFA (1,821 ± 588 μEq/liter), and GH levels comparable with those of the control subjects. There was some delay in BS elevation and disappearance and poor insulin release after the meal, with only two of nine having elevations of at least 13 μU/ml. The BS elevations and IRI responses, however, were adequate to block FFA release. GH levels were poorly suppressed by the meal but some infants had further elevations, possibly in response to protein. After partial rehabilitation, fasting BS and FFA and BS elevations after the meal were normal. A slight improvement in insulin release was apparent. Fasting GH levels and responses to the meal were normal.Fasting, minimally treated children with marasmic kwashiorkor (MK) had normal or low BS, normal or low IRI, normal FFA, and probably normal GH levels. There was considerable delay in BS elevation, moderately delayed glucose disappearance, and very poor or immeasurable insulin release after the test meal; FFA and GH were poorly suppressed. After partial rehabilitation, fasting BS was

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

ExtractThe behavior of nine patients with the de Lange syndrome was studied using videotape, a recording protocol of eight standardized stimulus conditions, and a visual, digital time reference which permitted precise coding and quantitative analysis. These patients avoid or reject social interactions and physical contact, and they do not distinguish in this between a stranger and the mother or her substitute. Social interactions with the adult stranger were scored inpatients 1–7as negative for 28–56 sec/min, whereas they were positive for 16 sec/min. Statistical significance was at the level ofP< 0.01. In the case of the mother negative responses ranged from 21–45 sec/min and positive from 3–27 sec/min. The patients exhibit infrequent facial expressions of emotion, and frequently display stereotypic movements. On the other hand, vestibular stimulation or vigorous movement appeared to be an effective means of eliciting pleasurable responses. When held in arms in the vertical position only one of nine children smiled at all and the frequency for that child was 0.8/min. When the child was bounced vigorously in the same position, all smiled but one who was too large to be bounced. In the eight the frequency of smiling ranged from 0.8–3.6/min. The data obtained indicate that a specific behavioral phenotype is associated with this syndrome.SpeculationIt seems clear that there is a distinct behavioral phenotype in the de Lange syndrome. We believe that this is only one of many such patterns of behavior that characterize children with clinical syndromes. The delineation of these phenotypes should provide important evidence on somatic determinants of behavior.

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

ExtractThe basal adenylate cyclase activity of the rat heart increases with the age of the animal. By itself, 10−5M glucagon activates only adenylate cyclase activity from adult rat hearts. In contrast, 10−5M glucagon in the presence of 10−4M 5'-guanylylimidodiphosphate (GMP-PNP) clearly activates adenylate cyclase activity in the 14-day-old rat heart, with some activation being evident in hearts of 7-day-old animals. GMP-PNP, 10−4M, activates adenylate cyclase activity by itself at ages of 14 days and older, but to a far lesser degree than in combination with 10−5M glucagon. Activity elicited by NaF increases throughout the neonatal period. The ratio of NaF-stimulated activity to basal activity increases from 6.3 at 2 days to 10.0 in the adult, a change which is not statistically significant.We conclude that a cardiac receptor for glucagon is present early in neonatal period of the rat, but this receptor cannot effect activation of adenylate cyclase and an increase in heart rate, or depletion of glycogen. Even in the presence of 10−4GMP-PNP, the response to glucagon by cardiac adenylate cyclase depends on the age of the rat. In heart cells from a 7-day-old rat, the response is barely measurable but the magnitude of the response increases each week.SpeculationThis study demonstrates that GMP-PNP, an analog of GTP, facilitates the activation of adenylate cyclase by glucagon in the neonatal rat heart. It remains to be determined whether GMP-PNP facilitates glucagon binding per se or the interaction of glucagon with adenylate clyclase. The effect of the naturally occurring GTP on newborn cardiac adenylate cyclase activity is unknown.

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

摘要:

ExtractTwenty-four jaundiced neonates were studied, 12 in the treatment group and 12 in the untreated group. Patients were randomly selected to receive oral riboflavin. The mean 24-hr bilirubin decrease was determined during phototherapy. Blue light (420–470 nm) energy ranged from 6–10 μW/cm2. The observed 24-hr bilirubin decrease was compared with the expected decrease based on an energy-dose-response relationship. Riboflavin-treated infants received either 6–7 μW/cm2blue light energy or 8–10 μW/cm2(same as control group). Those infants receiving less energy than the control group (8–10 μW/cm2) had a mean 24-hr bilirubin decrease (3.05 mg/100 ml/24 hr) equal to the control group (3.09 mg/100 ml/24 hr). Those riboflavin-treated infants receiving energy equal to the control group showed a greater decline (5.2 mg/100 ml/24 hr) in their mean 24-hr bilirubin. Although effective, additionalin vivostudies are required to clarify the full effects, especially on DNA, of using photosensitizers such as riboflavin in the presence of bilirubin and blue light energy (420–470 nm).SpeculationRiboflavin may become an inportant adjunct to phototherapy for neonatal hyperbilirubinemia. As a producer of singlet oxygen it is capable of transferring enough energy to overcame the oxygen quenching effect of bilirubin in its rapid degradation.

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1976

数据来源: OVID