ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Premature newborn rabbits, delivered by hysterotomy on day 27 of gestation, were tracheotomized at birth, kept in body plethysmographs, and subjected to pressure-generated ventilation at a working pressure of 25 cm H2O, 100% O2, and frequency 40/min. Thirty-seven animals received 50 μl of heterologous surfactant (phospholipid content 40 mg/ml) via the tracheal cannula before onset of artificial ventilation, eight were ventilated with a positive end-expiratory pressure (PEEP) of 6 cm H2O, and 44 served as controls. All animals were ventilated in a randomized sequence of 2-min periods with 20, 40, 60, or 80% inspiration time. After the experiment the trachea was clamped at end-inspiration and the lungs fixed by immersion in formalin. Plethysmograph recordings of tidal volume revealed that lung-thorax compliance was low in control animals, even at inspiration time 80% (mean ± S.E. = 0.17 ± 0.03 ml/cm H2O·kg). In animals treated with surfactant or PEEP, compliance was significantly improved at all ventilator settings. The highest mean compliance values, obtained at 60% inspiration time were 0.91 ± 0.07 and 0.73 ± 0.14 ml/cm H2O·kg in surfactant- and PEEP-treated animals, respectively. Compliance of surfactant-treated animals was significantly higher than that of PEEP-treated animals at inspiration time 40% (0.85 ± 0.07versus0.52 ± 0.13 ml/cm H2O·kg;P< 0.05). The relative volume of the alveolar compartment, determined morphometrically in histologic sections and expressed as the alveolar expansion index (Ia), was significantly higher in surfactant-treated animals than in controls (1.60 ± 0.12versus0.74 ± 0.06;P< 0.005), but not improved in animals ventilated with PEEP. In animals receiving surfactant, Iaincreased with the duration of the inspiration phase, from 0.99 ± 0.10 at 20% to 1.95 ± 0.22 at 80% inspiration time. There was also histologic evidence of enhanced recruitment of aerated alveoli in surfactant-treated animals ventilated with prolonged inspiration time.SpeculationThe air expansion of the premature neonatal lung can be enhanced to a significant degree by treatment with surfactant in combination with appropriate prolongation of the inspiration phase. Such a therapeutic regimen might be useful in the management of newborn infants with severe respiratory distress syndrome, requiring artificial ventilation; however, because excessive prolongation of the inspiration phase could have adverse effects on pulmonary hemodynamics and lead to hypoventilation with respiratory acidosis, the setting of the ventilator should be carefully adjusted with respect to the therapeutic response in patients with respiratory distress syndrome who are treated with supplementary surfactant.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Several membrane properties of vitamin E-deficient and normal erythrocytes were studied after incubation of these cells with hydrogen peroxide. Measurements of mean corpuscular volume, cation permeability, membrane Na+, K+ATPase activity, red cell filterability through 5 μ millipore filters, and membrane protein pattern on sodium dodecyle sulfate-gel electrophoresis revealed marked alterations before lysis. Vitamin E sufficient cells were unaffected by a similar incubation with hydrogen peroxide. We speculate that the changes in membrane function, which follow peroxidant injury, contribute to the shortened red cell survival in the vitamin E deficient state.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Human erythrocyte superoxide dismutase (SOD) was purified and specific antiserum was raised in rabbits. Enzyme preparations from adults and from newborns were shown to be indistinguishable in their immunologic and electrophoretic properties. Erythrocyte SOD was quantitated in blood specimens from adults and in cord blood specimens from neonates of different gestational ages, using both an immunologic and an activity assay. The mean values of SOD concentration and SOD activity for adults and for newborns of average size for gestational age (AGA) showed no significant difference. Adult red cells contained 28.0 ± 8.3 SOD units/mg hemoglobin (Hgb) whereas AGA neonatal red cells had 28.5 ± 8.3 SOD units/mg Hgb. Immunologic quantitation by single radial immunodiffusion revealed 0.69 ± 0.07 μg SOD/mg Hgb in adults and 0.70 ± 0.14 μg SOD/mg Hgb in the AGA neonates; however, the SOD concentrations from both small for gestational age (SGA) and large for gestational age (LGA) neonates were significantly lower than those of the AGA neonates and the adults (SGA: 0.57 ± 0.24 μg SOD/mg Hgb,P< 0.05; LGA: 0.59 ± 0.16 μg SOD/mg Hgb,P< 0.05).SpeculationThe relatively small quantitative differences in cytosolic superoxide dismutase are unlikely to account for an increased susceptibility to oxygen therapy. The possibility of a decrease in the mitochondrial superoxide dismutase isoenzyme has yet to be studied.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The immunogenic and antigenic properties of the cystic fibrosis glycopeptide and its normal counterpart were compared. BALB/c mice were immunized with either the cystic fibrosis glycopeptide or its normal counterpart and their spleen cells fused with X63NS1/1-Ag-4 (NS1) mouse myeloma cells. Four hybridization experiments (two with each glycopeptide) were performed in which different plating methods and screening assays were evaluated. Although an identical immunization procedure was used, 51 hybridoma cultures producing specific antibodies to the control glycopeptide and only 11 producing antibodies to the cystic fibrosis glycopeptide were obtained. Many of the monoclonal antibody preparations showed specificity toward the carbohydrate moiety of the glycopeptides and crossreacted immunologically with various glycoprotein preparations, whereas some were specific to the glycopeptides. The antibodies from the cloned hybridomas specific to the glycopeptide were used to compare serum fractions from controls and cystic fibrosis patients (10 samples in each group). Indistinguishable immunologic reactivity (antigenicity) between the controls and cystic fibrosis patients was demonstrated with the various monoclonal antibodies so far evaluated.SpeculationAlthough these findings indicate that the cystic fibrosis glycopeptide and its normal counterpart differed markedly in their ciliary dyskinetic activity and in their immunogenicity, they revealed both structural and antigenic similarity.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

In 23 infants and young children aged from 3 wk to 2 1/2 years, lung volume, by plethysmography, dynamic lung compliance and total pulmonary resistance with air-filled balloons and pneumotachography, have been measured in the supine and right lateral postures in order to observe any possible systematic differences in either body position. Fourteen subjects were studied under light sedation, the remaining nine under general anaesthesia before elective surgery. In the sedated group, no significant differences were found between the two positions for lung mechanics. In the anaesthetised group the only measurement that varied with position was dynamic lung compliance, being lower in the supine posture (P< 0.05). In one of the sedated infants with predominantly left sided lung disease, large position dependent changes in lung volume and lung mechanics were observed suggesting that care should be taken in interpreting lung function tests in infants with unilateral lung disease. In the anaesthetised subjects, the finding of reduced ratios of esophageal to mouth pressure change during brief airway occlusions, suggests that under these conditions pleural pressure changes were unequally distributed.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Sucrase-isomaltase (SI) was isolated by immunoprecipitation from the intestines of human fetuses of 16–20 wk of gestational age as one large polypeptide (pro-SI) with a molecular weight of 260,000. Treatment with elastase converted the pro-SI into two polypeptides of apparent molecular weights as sucrase and isomaltase from normal adult intestine (Mr140,000 and 150,000, respectively). The pro-SI had full enzymatic activity.SpeculationThe results indicate that human sucrase-isomaltase is synthesized as a single chain and that the pancreatic proteases play a significant role in the final processing of the molecule. The pro-SI is proposed to be present also in patients suffering from pancreatic insufficiency.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Continuous infusion of the short-chain fatty acid sodium octanoate into rabbits produces pathologic changes after 4 h. Principal abnormalities include microvesicular fatty accumulation in liver, and to a lesser extent in kidney, heart, and lungs. Ultrastructural changes include swelling and pleiomorphism of mitochondria in liver, and less consistently swelling of astrocytic food processes in brain, suggesting early cerebral edema. These changes are similar to the pathologic abnormalities observed in patients with Reye's syndrome.SpeculationInfusion of the short-chain fatty acid anion, octanoate, into rabbits reproduces the major clinical, biochemical, and pathologic changes observed in Reye's syndrome, and thus serves as a suitable experimental model for the human disease.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID