摘要:

ABSTRACT.A clinically adapted method for the calculation of the functional residual capacity in newborn infants has been developed. The method is based on a multiple breath nitrogen washout test, during which the ventilatory air flow and the nitrogen concentration signals are sampled by a minicomputer, which also performs the calculations. The ventilatory air flow is measured by a pneumotachometer connected to a face-out volume displacement body plethysmograph, and the nitrogen concentration by a nitrogen analyzer. The functional residual capacity volume is calculated from the sampled signals by adding the expired nitrogen volumes during each expiration, and finally dividing this sum by the initial alveolar nitrogen concentration. Before the calculations, the sampled signals are adjusted regarding nitrogen analyzer delay and plethysmograph characteristics. The method presented is designed to minimize the test equipment influence on the baby's respiration and also to inhibit the necessity of pneumotachometer compensations normally connected with washout methods. Furthermore, the calculated breath-by-breath values of end-expiratory nitrogen concentration, nitrogen volume, inspired and expired tidal volume, are stored on disk for further analysis and resimulation of the test. The method has been tested on a mechanical lung model and on washouts from healthy newborn infants. The model tests indicate that the accuracy and the reproducibility of the method are good, and the results from the infants are in good agreement with previously obtained results.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.We have studied the peripheral blood leukocytes from human infants in an assay involving the protection of neonatal mice from herpes simplex virus (HSV) infection by human antibody, interferon, and leukocytes. Recombinant DNA a-interferon (IFLrA), antibody, and Ficoll-Hypaque-purified mononuclear cells (MC) from human adults administered intraperitoneally protected neonatal mice from a lethal HSV challenge 1 day later (73.6% survival). MC obtained from human infants less than 130 days old in combination with IFLrA and antibody afforded no protection (15.2% survival;p< 0.0005 compared to survival with adults' MC). MC from infants over 130 days protected the neonatal mice (60% survival; not significantly different from survival using adult cells, but significantly (p< 0.0005) different than survival using MC from younger infants). The ontogeny of MC protection parallels the clinical development of resistance of infants to HSV infection.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.The use of a multiple gas rebreathing method for the measurement of cardiopulmonary function in mechanically ventilated neonates was evaluated. The following indices of cardiopulmonary function were assessed in 20 piglets (mean weight, 2.3 kg): 1) pulmonary capillary blood flow(Qc),2) diffusing capacity for carbon monoxide (DLco), 3) lung gas volume (FRC), 4) oxygen consumption(Vo2),and 5) volume of the pulmonary tissues and capillaries (VTPC), the latter an estimate of total lung water. During mechanical ventilation at zero end expiratory pressure, all rebreathing parameters correlated well with body weight. Additionally, a good correlation(r =0.81, slope = 0.99) between VTPC and postmortem estimate of total lung water was observed. The effect of ventilation with positive end expiratory pressure (PEEP) was then studied in 10 piglets. On increasing PEEP from zero to 15 cm H20, FRC significantly increased by 208%,Qcsignificantly decreased by 60%, and no changes in VTPC occurred. Seven piglets were then studied after induction of lung injury by oleic acid infusion. Compared with the pre-oleic acid infusion values, all the rebreathing variables decreased during ventilation without PEEP. Unlike the situation with the normal piglets, when PEEP was increased from zero to 10 cm H2O in the oleic acid-infused piglets, the values for FRC and VTPC significantly increased. Mean VTPC at 10 cm H2O was 20 ± 2 ml/kg which correlated well (r= 0.93) with the postmortem total lung water value of 19 ± 1 g/kg. Thus, multiple gas rebreathing methodology is applicable to studies using Small animals. The observation that the applicartion of PEEP in lung injury increased the accuracy of the VIPC measurement suggests that PEEP improves ventilation of injured lung segments.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.The concentration differences across the pregnant uterus of glucose, lactate, ketoacids, free fatty acids (FFA), and oxygen were determined in 21 chronically catheterized guinea pigs. Polyvinyl catheters were inserted into one of the ovarian veins and the right carotid artery around the 50th day of pregnancy. Postoperative recovery of maternal substrate concentrations in this preparation was evaluated in five animals. Elevated hemoglobin and ketoacid concentrations persisted up to the 4th day after surgery in the awake animal. In 16 animals between 54 and 62 days gestation, arterial and venous blood samples were collected between the 4th and 13th postoperative days. Arteriovenous substrate differences across the pregnant uterus (means ± SD) were as follows: glucose, 0.87 ± 0.22 mM; lactate, 0.31 ± 0.11 mM; and oxygen 4.77 ± 0.58 mM. There was no significant difference for ketoacids. In 10 animals, plasma FFA concentrations were determined. In nine animals, the arterial concentration was higher suggesting a net uptake of FFA by the pregnant uterus. Lactate production by the uterus accounted for approximately 18% of uterine glucose uptake if glucose is assumed to be the only source of uterine lactate production. The mean glucose/oxygen quotient across the uterus corrected for lactate output was 0.92 ± 0.34. It is concluded that glucose is a major metabolic substrate for the near-term uterus in the pregnant guinea pig and can account for most of the uterine oxygen consumption.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.Increased synthesis of type I collagen, leading to increased ratios of type I to type III collagen in the lungs, has been observed in the lungs of animals with experimental pulmonary fibrosis. Similar changes in collagen type ratios have been observed in lungs of humans dying of idiopathic pulmonary fibrosis and of adult respiratory distress syndrome. In this study, lung collagen type ratios were examined in infants with acute and chronic lung disease. Tissue from the right lower lobes of neonates was obtained post mortem. Specific collagen types were quantitated by solubilization of lung collagen with CNBr and fractionation of the resulting mixture of peptides by column chromatography and polyacrylamide gel electrophoresis. Ratios of type I/III collagen were calculated for each lung sample using two independent pairs of marker peptides for these determinations. In some cases the ratio of type Y to type III collagen in these same lung samples was also quantitated. We observed a significant increase in the ratio of type I/III collagen in infants with a premortem diagnosis of chronic lung disease, usually preceded by respiratory distress syndrome. We also observed two infants with large changes in collagen type ratios who might have had pulmonary fibroplasia secondary to intrauterine lung disease. These data suggest that there may be several subsets of infants with respiratory distress syndrome, each having a different prognosis.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.The mechanical properties of the newborn piglet gallbladder were evaluated in both the stimulated and unstimulated states. The pressure-volume relationships, compliance, and the estimated active tension of the gallbladder were determined in 10 newborn piglets (2–7 days of age). Agonist stimulation was achieved by administration of histamine (25 /μg/kg/h) and cholecystokinin (CCK) (60 ng/kg/h). Both histamine and CCK increased the intracholecystic pressure at the 50% resting volume from 12.4 cm H2O to 18.9 and 15.5 cm H2O, respectively. This resulted in a significant (p< 0.05) increase in the active tension. However, no significant changes were observed in the gallbladder compliance after stimulation. These findings characterize the mechanical properties of the normal neonatal gallbladder. The low magnitude of intracholecystic pressure response to agonist stimulation, when compared to adult data, may explain the occurrence of decreased neonatal choledochal bile flow.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.3-Methyladipic, 4-methylpimelic, 4-meth-ylsuberic, pimelic, and azeleic acids were identified by gas chromatography-mass spectrometry in the amniotic fluid of fetuses with propionic acidemia. These compounds were virtually undetectable in normal amniotic fluid. Concentrations much higher than those of the amniotic fluid were found in the urine of neonatal infants with propionic acidemia and methylmalonic acidemia. It appears that the accumulation of these compounds is a consequence of the accumulation of propionyl-CoA. Evidence was obtained for the presence of other methyl-branched chain dicarboxylic acids. 4-Methylpimelic acid and 4-methylsuberic acid have not previously been identified in human physiological fluids.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.To localize fetal rabbit lung β-adrenoreceptors before and after glucocorticoid treatment, light microscopic autoradiography was performed with the reversible radiolabeled β-adrenergic antagonist, [3H]dihydroalprenolol, on day 26 of gestation. Autoradiograms of adult lung and fetal myocardium were also prepared. Examination of these autoradiograms showed densely labeled airways, alveoli, and myocardium. Specific labeling, defined as that prevented by incubation with 1-propranolol (1 μM), was 90%. Analysis of grain counts in the fetus showed that airways were more densely labeled than alveoli(p< 0.001), labeling was increased by treatment(p< 0.001) and treatment increased alveolar(p <0.002) but not airway labeling. Adult lungs were much more densely labeled than fetal, and fetal myocardial labeling was not altered by treatment. Adult untreated lung showed the same pattern as fetal untreated lung with airways being more densely labeled than alveoli (p< 0.001). To validate estimates of relative β-adrenoreceptor concentration derived from autoradiograms, comparisons to determinations of β-receptor concentraion from scintillaiton counting of lung section digests and from previously performed radiologand binding studies, This increaes is not present in either airway or myocardial β-adrenreceptors and is consistent with the known maturational effect of glucocortiocoid treatment on fetal olveolar function.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

ABSTRACT.A rat model of focal segmental glomerulosclerosis (FSGS) produced by repeated injections of amino-nucleoside (AMN) of puromycin was used to evaluate the relative roles of hemodynamic alterations and AMN-induced glomerular visceral epithelial cell injury in the development of FSGS.Twenty rats received three intraperitoneal injections of AMN on days 1, 21, and 28 and developed significant proteinuria. On day 50, 14 rats (group 1) underwent selective left renal perfusion with AMN and six rats (group 2) received left renal perfusion with saline. At sacrifice on day 70 or 110, group 2 rats had similar values in left and right kidneys for glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and the amount of FSGS (13.1 ± 5.6% in left and 12.9 ± 7.8% in right). In contrast, group 1 rats manifested a significantly higher amount of FSGS in right kidneys as compared to left kidneys (3.1 ± 1.3% in left and 6.3 ± 2.0% in right, as well as significantly diminished GFR and ERPF in left as compared to right kidneys. A higher degree of FSGS was seen in kidneys with a higher GFR and ERPF. A positive correlation was observed between the mean 24-h protein excretion of the rats and the percentage of FSGS in left and right kidneys (r= 0.66,p< 0.01).

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID