摘要:

ExtractResponse of the ductus arteriosus and umbilical artery to changes in oxygen tension, to acetylcholine, and to sympathetic and parasympathetic blocking agents was studiedin vitroin isolated rings obtained from 22 fetal lambs of 98− to 147-day gestation.After stabilization of tension at a baseline level (0.3—0.7 g) in a Po2, environment of 35–45 mm Hg, both increase of the Po2to 550 mm Hg and decrease of the Po2to 8 mm Hg of the bathing solution produced constriction. The mean maximal tension developed by the ductus arteriosus was 3.91 g at high P0, and 3.87 g at low Po2. The increase in maximal tension developed with advancing gestation was also similar at both high and low Po2.At Po2, levels of 8–550 mm Hg, acetylcholine produced a further increase in tension, whereas bradykinin only produced an increase in tension at high PO2. Alpha and beta sympathetic blockade had no effect on the constrictor response to oxygen. Atropine relaxed the ductus arteriosus and umbilical artery at both high and low Po2levels; the degree of relaxation was related to drug concentration. Acetylcholin-esterase also relaxed the ductus arteriosus constricted by oxygen. The cholinesterase inhibitor, edrophonium, produced ductus constriction at P0, of 35–45 mm Hg with little further effect from high Po2. The constrictor effect of high or low Po2on the ductus arteriosus and umbilical artery seems to be mediated through release of acetylcholine.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractDilinoleyl lecithin (DLL), identified as a component of a crude mixture of soya bean phospholipids (SBP), was obtained in highly pure form by synthesis. The DLL was administered to 25-day pregnant rabbits in doses of 1.0 and 2.0 g/rabbit. One unit of oxytocin was administered intramuscularly 24, 48, and 49 hr after infusion, and the rabbits were observed for abortion. The abortion rate after the 1.0-g dose of DLL was 56.9 ± 6.9% and that after the 2.0-g dose was 100.0 ± 0%; the rate in controls was 2.6 ± 2.6%.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractElectrophoretic properties of glucose-6-phosphate dehydrogenase (G6PD) were studied in mother-infant pairs and in young and old erythrocytes of adults. G6PD isoenzymes of erythrocytes of newborn infants migrated at rates 3–4% faster than the corresponding isoenzymes of maternal erythrocytes. Analysis of hemolysates of young and old erythrocytes of adults revealed that G6PD of young cells also moved about 3% faster than that of old cells. In contrast, active enzyme sedimentation analysis revealed that the G6PD enzyme proteins of old and young erythrocytes of adults, of newborns, and of their mothers sedimented with essentially identical rates (S20,w = 6.8). Migration in gels of different acrylamide concentrations and velocity sedimentation analysis indicated that the G6PD of old and of young erythrocytes was in the same state of aggregation. Extensive equilibration of the hemolysates with nicotinamide-adenine dinucleotide phosphate (NADP) by filtration through Sephadex G-25 induced a clear increase in the migration rate of the G6PD of old cells of adults and of mothers at term to the rate characteristic of the enzyme of neonates and of young cells of adults. Experiments in which NADP was labeled with14C indicated that, in the process of gel nitration, the NADP content of the aged G6PD was restored. Thus the rate of migration of G6PD in acrylamide gel seems to be a function of the amount of NADP bound.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractThe activity of amino acid transport pathways in the small intestine of the 2-day-old rat was investigated. Transport was determined by measuring the uptake of 1 mM concentrations of various amino acids by intestinal segments after a 5− or 10-min incubation and it was expressed as intracellular accumulation.The neutral amino acid transport pathway was well developed with intracellular accumulation values for leucine, isoleucine, valine, methionine, tryptophan, phenylalanine, tyrosine, and alanine ranging from 3.9–5.6 mM/5 min. The intracellular accumulation of the hydroxy-containing neutral amino acids threonine (essential) and serine (nonessential) were 2.7 mM/5 min, a value significantly lower than those of the other neutral amino acids. The accumulation of histidine was also well below the level for the other neutral amino acids (1.9 mM/5 min). The basic amino acid transport pathway was also operational with accumulation values for lysine, arginine and ornithine ranging from 1.7–2.0 mM/5 min. Accumulation of the essential amino acid lysine was not statistically different from that of nonessential ornithine. Accumulation of aspartic and glutamic acid was only 0.24–0.28 mM/5 min indicating a very low activity of the acidic amino acid transport pathway. Accumulation of sarcosine and betaine was about 0.5 mM/5 min, which indicates a low activity for the imino acid-glycine pathway. The presence of 1 mM alanine significantly (P< 0.01) increased the accumulation of lysine by 28.5%, which suggests the presence of an exchange transport system.These results show that by operation of the neutral and basic amino acid transport systems, the neonatal rat can effectively absorb all the essential amino acids; however, accumulation of individual amino acids appears to be governed by structural rather than nutritional considerations.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractPrenatal diagnosis of Niemann-Pick disease was confirmed by deficiency of sphingo-myelinase activity and increase in sphingomyelin content in the liver of an affected fetus. Morphologic findings included cellular enlargement with cytoplasmic vacuolization and eccentric nuclei on light microscopy, increased deposition of phos-pholipids demonstrated by lipid histochemistry, and increased acid phosphatase activity by enzyme histochemistry.When visualized under electron microscopy, lipid cytosomes characteristic of the sphingolipid storage diseases were seen in hepatocytes, splenic cells, the endothelium and pericytes of cerebral vessels as well as in occasional neurons. Sphingolipid accumulation and morphologic findings indicate that biochemical and pathologic manifestations are well advanced in organs destined to produce the earliest clinical signs.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractSerotonin (5HT) transport and metabolism were studied in platelets from 14 trisomy-21 patients who were matched with 12 sibling and 9 non-sibling control subjects with regard to age, sex, home environment, diet and weight. Endogenous 5HT content, in nanograms per milligram platelet protein, was reduced from 446 ± 66 in the sibling controls and from 492 ± 74 in the non-sibling controls to 158 ± 16 in the Down's syndrome group, a difference of 61% and 68% respectively (P < 0.001). Initial uptake of14C-5HT measured after a 3-min incubation period was reduced 35% (P< 0.05) in the platelets from Down's syndrome patients, while the efflux of radiolabeled amine from platelets was not significantly altered in these patients. Since platelets do not synthesize 5HT, the decreased transport found may explain the lower 5HT levels in these patients. Mongols did not differ from control subjects in the activity of platelet monoamine oxidase.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID

摘要:

ExtractErythrocyte stromal lipid analysis has been performed on 26 healthy children spanning the age groups from 6 months to 14 years of age. Total lipid, lipid phosphorus and cholesterol per cell are similar in children between the ages of 6 months and 6 years. These values, in milligrams, for the 6–12 month age group are (4.42 ± 0.42) X 10-10, (0.98 ± 0.08) X 10-11and (1.22 ± 0.04) X 10-10, respectively. After 6 years of age, there is an increase toward the adult values, with children in the 10–14 year age group having values, in milligrams per cell, of: total lipid, (4.83 ± 0.32) X 10-10; lipid phosphorus, (1.15 ± 0.10) X 10-11; cholesterol, (1.26 ± 0.06) X 10-10. Changes in cell lipid content reflect primarily changes in cell size over the age period studied. In the younger age groups, the percentage of total lipid as phospholipid is lower and that as cholesterol is higher than in children over age 6 and in adults (age group 6–12 months, percentage of total lipid as phosphorus = 2.22 ± 0.05, that as cholesterol = 27.7 ± 3.0; age group 10–14 yr, percentage as phosphorus = 2.39 ±0.17, percentage as cholesterol = 26.1 ± 1.8). Phospholipid fractionation reveals a consistent level of sphingomyelin so that average values for all age groups studied range only from 23.9% to 24.4% of total phospholipid. Phosphatidyl choline is lowest in the youngest children studied (25.5% in age 6–12 months), and increases to adult levels after 6 years of age (28.8% in age group 6–10 yr; 28.2% in age group 10–14 yr). Consequently, the ratio of sphingomyelin phosphatidyl choline more closely approximates the neonatal value below 6 yr and the lower adult value after 6 yr. Fatty acids es-terified to phospholipid remain relatively constant throughout the age groups studied and do not differ markedly from adult values by the end of the first year of life.

ISSN:0031-3998    

出版商:OVID    

年代:1972

数据来源: OVID