摘要:

The hypothesis that the diminished motility of human milk leukocytes is due to a decrease in adherence was tested by using a collagen gel system in which leukocyte movement is less dependent on adherence. Unfractionated human milk leukocytes (HML) or fractionated peripheral blood leukocytes were placed on collagen gels in microwells and the leading edge of migration was determined by inverted phase microscopy. The mean rates of invasion of HML, blood neutrophils, and mononuclear blood leukocytes were 14, 240, and <1 μ/h, respectively (p< 0.01). We then examined the identity of motile HML by immunoperoxidase techniques using antibodies to selected cell markers. Motile HML were positive for a specific macrophage marker (cathepsin B) and a neutrophil and monocyte marker (Mac-1) but were negative for specific neutrophil (cathepsin G) or lymphocyte markers (CD3 and CD5). The directed motility of these cells was not enhanced by exposure to the chemoattractant, N-formyl-L-methionyl-L-phenylalanine, but was inhibited by a T cell lectin, phytohemagglutinin. The movement was actin dependent but was not dependent on calcium or Mac-1 surface glycoproteins. Thus, the diminished motility of milk neutrophils does not appear to be due to decreased adherence per se, and those HML that are motile are macrophages. This suggests a dichotomy for the function of HML. Neutrophils may be relegated to the lumen of the alimentary tract, whereas macrophages may penetrate into mucosal sites for host defense.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

We evaluated the feasibility of using thein vitrotransverse rat hippocampal slice as a model to study the effect of bilirubin on neuronal activity. Bilirubin in concentrations from 100 μmol/liter to 1 mmol/liter with bovine serum albumin as a stabilizer caused a significant decrease in the slope of the field excitatory postsynaptic potentials, concomitant with a significant increase in the peak latency of the population spike. These changes were partially reversible when bilirubin was removed from the incubation fluid. A partially reversible shift to the right of the presynaptic fiber volley/field excitatory postsynaptic potential relationship was interpreted as an expression of a reduction in synaptic activation. A partially reversible shift to the left of the field exitatory postsynaptic potential population spike relationship was interpreted as an expression of increased postsynaptic excitability. In conclusion thein vitrorat hippocampal slice was used successfully to study the effect of bilirubin on neuronal activity. A depressive effect of bilirubin was observed.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Cell-mediated immunity is not well characterized in very low birth weight infants, and abnormalities may represent a significant vulnerability to infection. This report describes 165 serial studies in 58 infants between 700 and 1300 g birth weight during the first 8 wk of life. Two ml of blood were drawn at 2-wk intervals to measure T cell numbers and subsets and response to phytohemagglutinin (PHA). Overall, lymphocyte proliferation to PHA averaged 17,264 cpm, significantly less than the adult control (23,566 cpm). T cell numbers and subsets were CD3 62% (adult controls 75%), CD4 45% (49%), and CD8 18.6% (27%). Values at birth were lower as all parameters increased for at least the first 4 wk of life: PHA at birth was 15,464 cpm, CD3 48%, CD4 37%, and CD8 13%. Because of the lymphocytosis of premature infants, the absolute numbers of total T cells and subsets were within the normal adult range despite less than 50% of the mono-nuclear cells at birth being T cells. A study of five infants demonstrated an average of 52% B7+ cells at birth showing that the number of B cells at birth was increased approximately 10-fold over the control number in adults. Clinical correlation showed that the increases in both the % CD8 and the absolute number of CD8+ lymphocytes after birth were correlated with both the occurrence of sepsis and the number of red cell transfusions. In summary this study assessed lymphocyte subsets in a sizeable number of very low birth weight infants serially during the first 8 wk of life including lymphocyte function using isolated mononuclear cells. It demonstrated that premature infants are different from adults controls and full term newborns in: 1) having decreased lymphocyte proliferative response to PHA, 2) having lower % CD3 and CD8, and 3) having an increased number of B cells at birth.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

To test the hypothesis that regional growth of lung parenchyma depends on regional distending pressure, left cervical phrenectomy was done in ten 2-month-old piglets. The unilateral diaphragmatic paralysis reduced mean transpulmonary pressure in the left hemithorax from 5.5 ± 1.0 (X ± SD) to 2.5 ± 1.2 cm H2O (p< 0.01,n= 5). When five of the piglets were killed 48 h later, wet lung weight, total protein content, and nucleic acid content did not differ from values in the five sham operated controls. The five remaining phrenectomized piglets were compared to their five sham-operated controls 7 days after surgery. Wet weight of the left lung was reduced by 29% (p< 0.01) and DNA content was reduced by 18% (p< 0.05). Wet weight of the right lung, contralateral to the paralyzed hemidiaphragm, was reduced by 11% (p< 0.05). At this time, body weight, bilateral transpulmonary pressure, and ratios of total protein/DNA and RNA/DNA in lung tissue did not differ from the sham-operated controls. These results suggest that regional growth of lung parenchyma by cell proliferation adjusted to changes in regional transpulmonary pressure caused by the unilateral phrenectomy.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Developmental changes in the myocardial diastolic ventricular interaction of hearts excised from 12 preterm (126 ± 0.8 SE days gestation; term = 147 days) and eight newborn (2.5 ± 0.2 SE days postnatal age) lambs were evaluatedin vitro.The excised hearts were immersed in a cold cardioplegic solution during which time compliant balloon catheters were inserted into the right and left ventricles through the pulmonary artery and aorta, respectively. The catheters were alternately connected to an infusion pump and appropriate transducers in order to obtain simultaneous biventricular pressure and volume measurements as the volume of each ventricle was varied. Computerized analysis of the pressure and volume recordings was used to determine right and left ventricular free wall compliance, ventricular septal compliance, and pressure and volume transfer functions. Ventricular septal compliance was significantly less than the free wall compliances within both groups. Ventricular septal compliance (p< 0.05) and transfer functions (p< 0.05) in the preterm were significantly lower than in the newborn. No significant differences in ventricular free wall compliances were found between or within age groups. These findings demonstrate an increase in ventricular coupling and functional interaction with development, potentially attributable to an increase in septal compliance with development.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

The predominant inflammatory cell type within the alveolar structure in bronchopulmonary dysplasia (BPD) is the alveolar macrophage (AM). AM ability to release hydrogen peroxide, a way to evaluate the cell status, was studied in nine infants who developed clinical and radiological evidence of BPD, and was compared to those from infants without lung parenchymal disorders (n= 6). AM were collected by bronchoalveolar lavage which was done after the mechanical ventilation stage in the BPD group. The experiments were performed on unstimulated AM and on AM stimulated by phorbol myristate acetate. Results revealed that the amount of hydrogen peroxide accumulated in the culture medium was significantly enhanced in the BPD group, in both experimental conditions (p< 0.01 and < 0.001, respectively). Furthermore, improvement of patients treated with glucocorticoids was closely related to a reduction of the alveolitis with a decrease of AM ability to generate hydrogen peroxide. These data indicate that AM activation is a central component of alveolitis in BPD and that extracellular production of oxidants by stimulated AM may play a critical role in the pathogenesis of the disease.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

There is a paucity of information on the significance of insulin on neonatal cerebral glucose metabolism. The effect of insulin on neonatal cerebral glucose uptake and cerebral cortical metabolic intermediates was investigated with the euglycemic hyperinsulinemic clamp in unanesthetized beagles during the first day of life. Insulin was infused at various rates to sustain an elevated steady state plasma insulin concentration in individual pups. Furthermore, blood glucose and 2-deoxyglucose levels were also maintained (“clamped”) in a steady state by infusion of glucose and 2-deoxy-[14C]-glucose. Mean (± SD) plasma insulin levels were 20 ± 12 and 2971 ± 3386 (33–14330) μU/ml in control and hyperinsulinemic pups. Blood glucose concentration was 4.43 ± 2.64 mM during basal periods and 4.54 ± 2.87 mM during the clamp period in study pups. Basal fasting glucose utilization in study pups was 43.9 ± 24 μmol/kg/min and increased to 60.9 ± 35.2 μmol/kg/min (p< 0.001) during hyperinsulinemia. Immediately after the euglycemic hyperinsulinemic clamp or fasting in control pups, the cerebral cortex was frozen to the temperature of liquid nitrogen. No differences were noted for any cerebral cortical intermediate between the two pup groups. In addition, there was no relationship between the cerebral intermediates concentration when analyzed as a function of plasma insulin levels. The uptake of cerebral 2-deoxyglucose was analyzed as a function of plasma insulin concentration (120–6900 μU/ml). Brain tissue demonstrated a positive linear relationship for 2-deoxyglucose uptake as a function of plasma insulin concentration. Although static determination of brain metabolites were not influenced by hyperinsulinemia, there was a positive effect of insulin on cerebral glucose uptake. Either directly or indirectly, insulin may increase brain glucose utilization in the newborn dog.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Glucose utilization by the placenta and individual fetal tissues was studiedin vivoin conscious pregnant rabbits at 29 days of gestation. In the fed state, the rate of glucose utilization was similar in the placenta and the gravid uterus, suggesting that the rate of fetal glucose utilization was approximately 40 nmol/min/g. A 96-h maternal fast induced a significant decrease in glucose utilization by the myoendometrium and in the glucose utilization index by fetal liver and brown adipose tissue. No modification was observed in other fetal tissues. These results indicate that glucose utilization by the placenta and the whole fetus from 96-h fasted rabbits does not decrease despite profound changes in endocrine and metabolic maternal parameters.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Pulmonary surfactant proteins SP-B and SP-C were isolated from lavage fluids of bovine lungs and recombined (lipid/proteins, 9/1, wt/wt) with dipalmitoyl phosphatidylcholine for testingin vitroand in surfactant-deficient adult rats. Using a pulsating bubble surfactometer, we found that inflation pressures of bubbles at minimum radii in these mixtures were 0.34 ± 0.05 cm H2O (± SD,n= 24) after 1 min. These values were not affected by increasing amounts of surfactant protein relative to dipalmitoyl phosphatidylcholine (DPPC). Minimum inflation pressures were similar to those of modified bovine surfactant, surfactant Tokyo Akita (TA) (0.33 ± 0.05 cm H2O,n= 7).In vivotesting was carried out in adult rats made surfactant deficient by repeated lavage and ventilated with 100% oxygen. Rats received tracheal instillations of either air, DPPC, DPPC/SP-B,C (9:1), or surfactant TA at 50 mg/kg body weight. Surfactant TA and DPPC/SP-B, SP-C mixtures resulted in similar immediate and sustained improvements in arterial oxygenation (308 ± 66 torr,n= 10 and 312 ± 101 torr,n= 6 at 30 min posttreatment) that were significantly greater than those of sham (76 ± 24 torr,n= 17) and DPPC-treated rats (64 ± 32 torr,n= 7). Rats treated with either DPPC/SP-B,C mixtures or surfactant TA showed similar postmortem static lung compliances (2.3 ± 0.8 ml/cm H2O/kg,n= 8 and 1.9 ± 0.4 ml/cm H2O/kg,n= 5, respectively) that were significantly larger than sham (1.3 ± 0.3 ml/cm H2O/kg,n= 14) and DPPC-treated rats (1.2 ± 0.2 ml/cm H2O/kg,n= 6). We conclude that simple mixtures of DPPC and SP-B,C duplicate results found with more complex mixtures of pulmonary surfactants.

ISSN:0031-3998    

出版商:OVID    

年代:1988

数据来源: OVID