ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryThymidine kinase activities, virtually all soluble in rat lung, liver, and small intestine, descreased abruptly late in gestation or immediately after birth. An injection of thyroxine delayed the fetal but not the neonatal changes in liver activity. An injection of cortisol decreased hepatic and pulmonary thymidine kinase activities in both fetal and neonatal rats but had little effect on the intestinal enzyme. Premature extrauterinization led to an earlier occurrence of the quantitative changes in thymidine kinase activity usually seen at term. Birth-associated changes included a rapid transitory increase in the hepatic enzyme and the virtual loss of intestinal thymidine kinase activity.In human tissues, the soluble thymidine kinase in liver remained high between the 11th and 22nd wk of gestation whereas the particulate enzyme, the predominant form in adult liver, rose in the second half of gestation and reached adult levels at birth. In human lung, the soluble enzyme started to decrease by the 16th gestational wk, whereas the particulate thymidine kinase reached the higher adult levels late in gestation. Thymidine kinase in adult human tissues was predominantly particulate.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryPulmonary arterial infusion of prostaglandin E1(mean dose, 1 μg/kg/min) in term neonatal lambs ventilated with room air resulted in a slight fall hi pulmonary arterial pressure (P≤0.05). Infusion during ventilation with low oxygen mixtures resulted in a parallel fall in pulmonary and arterial pressures and resistances. Intrapulmonary infusion of acetylcholine (mean dose, 3.9 μg/kg/min) in lambs during ventilation with room air caused a slight fall in mean systemic arterial pressure and systemic vascular resistance. When repeated with low oxygen ventilation, infusion of acetylcholine caused a parallel fall in both pulmonary and systemic arterial pressures and resistances. Infusion of tolazoline at a mean dose of 0.21 mg/kg/min did not change pulmonary or systemic arterial pressures or resistances when the lambs were ventilated with room air or with hypoxic gas mixtures although individual animals experienced marked falls in systemic arterial pressure.Pulmonary arterial infusion of each of the three vasodilators during hypoxic ventilation resulted hi potentially adverse hemodynamic effects. This occurred despite prior ductal ligation, implying that doses effective for pulmonary vasodilatation may exceed doses without systemic effects particularly hi the acute hypoxic state.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryMetabolic observations during early stages of hyperammonemia in two infants with ornithine transcarbamylase deficiency suggest that plasma α-ketoglutarate concentration ([α-KG]) becomes subnormal before the development of hyperammonemic coma. In one case, plasma [NH4+] remained normal until 40 days of age when it rose to 57 μM. However, this hyperammonemia was preceded by a fall in plasma [α-KG] to 15 μM at 27 days of age. It was only after severe hyperammonemia was established at 50 days of age that coma supervened. In the second case, plasma [α-KG] became subnormal (14 μM) 8 days before the rise in plasma ammonium concentration [NH4+] (52 μM) and 14 days before the onset of hyperammonemic coma. In eight patients with urea cycle enzymopathies, there was a highly significant (P≤0.01) negative linear correlation between [NH4+] and [α-KG]. In patients with portal-systemic encephalopathy, there was a similar relationship between [NH4+] and [α-KG], although the absolute [α-KG] levels in these patients were normal (23 ± 4 μM) while the patients were hyperammonemic (88 ± 25 μM).

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryHyperviscosity was produced in one member of each of 7 sets of twin newborn lambs by an exchange transfusion with 500 ml maternal packed red blood cells. The remaining seven control twin lambs underwent an identical exchange with maternal whole blood. Postexchange hematocrits were 63 ± 6 and 29.0 ± 3% (mean ± S.E.), respectively (P≤0.01). Whole blood viscosity measured at 3 rpm increased from 3.2 ± 0.4 centipoise (cps) to 14.4 ±6.1 cps in the lambs made hyperviscous (P≤0.01) and remained unchanged in the control lambs (2.2 ± 0.2versus2.8 ± 0.3 cps).A 2-hr steady state glucose infusion was performed on each lamb before and after the packed cell or whole blood exchange transfusion. Mean steady state plasma glucose concentrations were significantly decreased from pre-exchange steady state glucose infusion levels in the same lambs made hyperviscous (P≤0.05), whereas steady state glucose levels increased from pre-exchange levels in the twin lambs exchanged with maternal whole blood. Mean plasma insulin and glucagon values for the hyperviscous and control lambs remained unchanged during the glucose infusion.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryPlasma volume and red cell mass of various organs in piglets aged 24 hr (n= 7) and 7 (n= 6), and 14 (n= 6) days were measured using99mTc-labeled albumin and51Cr-labeled red blood cells. Organ activities were counted in a whole-body counter. Blood volume and hematocrit were calculated. The blood volumes in μl/g varied markedly between various organs. The lowest blood volumes at 24 hr of age were found in skin (21.9 ± 5.0 μl/g), brain (33.3 ± 8.4), and skeletal muscle (35.5 ± 7.4). The highest values at this age were noted in liver (670.0 ± 89.1), lung (533.8 ± 80.7), spleen (332.0 ± 82.8), and kidney (300.6 ± 55.5). Blood volumes of about 150 μl/g were observed in heart muscle and thyroid gland and those of about 100 μl/g in thymus and gastrointestinal tract. The total blood volume was 100.2 ± 3.9 μl/g at 24 hr and remained unchanged during the first 2 wk of life. A significant decrease in relative blood volume with growth was noted in liver and lung (P≤0.01), and in skeleton (P≤0.05). The blood volume, contained in the great vessels outside the organs, increased from 29.5 ± 5.5% of total blood volume at 24 hr to 31.2 ± 5.7% at 7 days and to 38.2 ± 7.5% at 14 days of life. The total body/venous hematocrit ratio was about 0.84. Accordingly, tissue hematocrits of most organs were below the venous hematocrit. Only in spleen was the tissue/venous hematocrit ratio (TH/VH) higher than 1.0. TH/VH of brain, gastrointestinal tract, thyroid gland, and thymus approached unity. The lowest TH/VH was found in kidney (0.54 ± 0.08 at day 1). In skin, the TH/VH decreased from 0.98 ± 0.10 to 0.82 ± 0.07 during the first 2 wk of life.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID