摘要:

ABSTRACTSIt is not known if milk antibody protects infants from herpes simplex virus (HSV) infection. As a first step to test this hypothesis, anti-HSV antibodies were studied in human milk. Paired serum and milk samples were analyzed for anti-HSV antibodies by ELISA, Western biot analysis (WBA), neutralization (NT) plaque assay, and antibody-dependent cellular cytotoxicity (ADCC) assay. Nineteen of the 20 serum samples showed anti-HSV activity by ELISA and ADCC, and 18 showed activity by WBA and NT. We found a significant association between the immunoassays for detection of anti-HSV antibodies in sera. Fewer of the human milk samples showed anti-HSV activity: only one milk sample was positive by ELISA and one by NT assay, four by ADCC and 12 by WBA. The milk sample from the seronegative donor was also negative. We found a poor association of antibody titers in human milk and serum antibody titers using ELISA, NT, and ADCC assays. There was a significant (p = 0.022) association between serum and milk results using WBA. Among the four assays, WBA was the most sensitive for antibody detection. It will be used in an on-going prospective study to determine the role of anti-HSV antibody in the protection against HSV infections in infants. (Pediatr Res31: 591–595, 1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSPentoxifylline (PTXF) is a methylxanthine that modifies leukocyte function and inhibits cytokine release. To evaluate its effects on the cardiovascular manifestations of sepsis secondary to group B streptococci, 14 anesthetized, mechanically ventilated piglets were studied over a 240-min period. Animals were randomly assigned to a treatment group that received a PTXF bolus (20 mg/kg) followed by a continuous infusion of 5 mg/kg/h before and during group B streptococci (1 x 108colony forming units/kg/min) administration and a control group that received saline as a placebo. Comparison of the hemodynamic measurements and arterial blood gases during the first 90 min of PTXF treatment with those of the control group resulted in the following 90 min values: systemic arterial blood pressure was significantly higher in the PTXF group (89 ± 10versus56 ± 30 mm Hg; P < 0.005) as was cardiac output (0.18 ± 0.04versus0.10 ± 0.07 L/kg/min; p < 0.005). Pulmonary vascular resistance remained lower in the PTXF-treated animals (135 ± 117versus248 ± 119 mm Hg/L/min/kg; P < 0.001), and these animals were less acidotic as measured by pH (7.07 ± 0.2versus7.31 ± 0.1; p < 0.05) and base deficit (-15 ± 9versus−5 ± 2 mmol/ L;p < 0.05). Median survival time was significantly longer in the PTXF group (210versus90 min; p < 0.002). These data demonstrate that PLXF can ameliorate some of the deleterious hemodynamic manifestations of group B streptococci sepsis and result in improved survival in a young animal model. (Pediatr Res31: 596–600, 1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSWe examined the linkage of cholinergic receptors to the phosphoinositide signaling pathway to elucidate one facet of the autonomic response mechanism in fetal and adult sheep. Cholinergic stimulation with carbachol increases the production of3H-inositol mono-, bis-, and trisphosphates in a time- and concentration-dependent manner in both fetal and adult myocardium. However, the maximal stimulation of inositol polyphosphates above basal activity was much greater in fetal (120 ± 11%) than in adult (20 ± 7%) myocardium (mean ± SEM). Saturation binding analysis of myocardial muscarinic receptors using3H-N-methylscopolamine revealed significantly higher receptor concentration in fetal (240 ± 25 fmol/mg protien) than in adult (78 ± 15 fmol/mg protein) myocardium (mean ± SEM). Binding competition studies revealed a pattern of selectivity—atropine < 4-diphenylacetoxy-N-methylpiperidine methiodide < piren-zepine < (4-hydroxy-2-butynyl)-1-trimethylammonium m-chlorocarbanilate chloride < 11–2[[2-[(diethylamino)-methyl]-1-piperdinyl]acetyl]-5,11− dihydro-6H-pyrido[2, 3-b[[1, 4]benzodiazepine-6-one 116—compatible with the presence of muscarinic receptor (MR)2, MR3, and/or MR5 subtypes. Receptor subtype determination by Northern blot analysis revealed mRNA specific for the MR2 subtype in both fetal and adult myocardium, although expression was greater in fetal heart. We conclude that decreases in MR2 subtype protein and mRNA levels parallel the age-related decrease in carbachol-stimulated PLC activity. Our studies demonstrate differences between fetal and adult myocardium in the concentration of muscarinic cholinergic receptors and their linkage to a putative calcium mobilizing signaling pathway and suggest that this pathway may play a different role in the fetus than in the adult. The physiologic significance of this age-dependent change in cholinergic-linked signaling response of the myocardium is not yet known. (Pediatr Res31: 601–605, 1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSInfants who subsequently succumb to the sudden infant death syndrome (SIDS) have higher heart rates and reduced heart rate variation compared with other infants. We examined dynamic changes in cardiac interbeat intervals to explore these differences in cardiac control. Recordings of electrocardiographic activity and respiratory movement were acquired from 13 SIDS victims before their deaths. Moment-to-moment changes in R-R intervals during quiet sleep, rapid eye movement sleep, and waking were compared with values of 13 matched control infants. For each sleep-waking state, every R-R interval was plotted against the previous interval (Poincaré plots), and each change in interbeat interval was plotted against the previous change. Dispersion of interbeat intervals at different heart rates was reduced in SIDS victims, resulting in Poincaré plots markedly different from those of controls. The dispersion, sampled at the 10th and 90th percentiles of heart rates, was reduced across all sleep-waking states in SIDS victims. At high heart rates, the difference between groups disappeared after correcting for basal rate; however, the reduced range at low heart rates was independent of basal rate. SIDS victims also showed smaller beat-to-beat changes in heart rate and fewer sustained runs of consistenl heart rate changes during waking relative to controls. The differences in cardiac rate dynamics suggest altered autonomic control in infants who succumb to SIDS. We speculate that the autonomic disturbance may lead to cardiac instability or may indicate CNS alterations with the potential to affect other vital functions. (Pediatr Res31: 606–612, 1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSRespiratory training of premature infants was performed to determine whether improved respiratory muscle strength and/or endurance would result. Twenty-two premature infants were randomized into control and training groups for 2 wk, using inspiratory flow-resistive loads for training (75 cm H2O-L-1-s in wk 1 and 90 cm H2O-L-1-s in wk 2). Respiratory endurance was assessed by the time interval required for the development of a 5-torr rise in transcutaneous CO2tension during the hypoventilation induced by loaded breathing, using a moderately severe resistive load (250 cm H2O-L-1-s at 1 L-min-1). Respiratory strength was assessed by the maximum negative airway pressure generated during occluded breaths, a pressure-time integral, and an effort index. Results revealed that respiratory muscle endurance, which was not initially different between control and trained groups, increased significantly after 2 wk in the trained group by 137% (median value,p< 0.05), whereas it remained unchanged in the control group (-24%). The trained group of infants also showed a significant decrease in baseline breathing frequency between the initial and final measurements taken 2 wk apart when compared with controls (p< 0.05) and a lesser increase in inspiratory time with loading in the final measurement as compared with the initial value (p< 0.05). There was no significant difference between the control and trained groups in initial or subsequent measures of respiratory muscle strength. Inspiratory flow-resistive load training appears to improve the respiratory endurance of premature infants in whom respiratory muscle fetigue has been described to play a role in the development of respiratory failure. (Pediatr Res31: 613–618, 1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSLittle is known of the development of efficient coordination between suckle feeding and breathing in human infants. To establish baseline data, we recorded breathing and swallowing activity during bottle feeds in 23 infants at 14–48 h postnatal age. Most swallows (overall mean 68%) were organized into runs, with intervals starting at 0.6–0.8 s and slowing to 1–1.3 s after 30–40 s. The proportion of run swallows to total swallows increased significantly with age. Swallow intervals were regular (coefficient of variation = 18–38%) compared with breathing (coefficient of variation = 50%). Both breathing rate and tidal volume were significantly reduced by the onset of suckle feeding, and the pattern of respiratory airflow became markedly irregular. Mild transient desaturation was common, but was not accompanied by changes in heart rate. Swallows could occur in all phases of breathing. Overall, equal numbers of swallows were preceded by expiration and inspiration, but twice as many were followed by expiration compared with inspiration. Swallows were classified by the respiratory phases both preceding and following the swallow. Swallows occurred in all possible classifications in each of the infants studied. The incidence of the most frequent classification (inspiration-swallow-expiration), was 24% overall (individual range 5–50%). The phase relation between swallows and breaths changed frequently but showed occasional short periods of stability during which the breathing became regular and tidal volume increased. We conclude that atPediatr Res31: 619–624, 1992

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSMeconium aspiration continues to be a major cause of morbidity and mortality in newborn infants and is one of the most common indications for extracorporeal membrane oxygenation. Lab studies have suggested that meconium inactivates surfactant and displaces surfactant from the alveolar surface. A recent report has suggested a clinical role for surfactant therapy in human infants with meconium aspiration. We evaluated the effect of surfactant (Survata) lavage on a piglet model of meconium aspiration. Meconium pneumonitis was created by administration of 4 mL/kg of a 20% slurry of human meconium via endotracheal tube. Twenty-four newborn piglets were then randomly assigned to one of three groups:I) suction only (n= 7),2) saline lavage (n= 5), or3) surfactant lavage (n= 7). Five piglets were excluded from analysis due to death from pneumothorax during meconium administration (n= 3), death from pneumothorax during saline lavage (n= 1), and death from pneumothorax during surfactant lavage (n=1). The surfactant group had a statistically significant (p< 0.05) improvement in arterial to alveolar oxygen ratio gradientversusboth control groups for the first 3 h. The oxygenation index was statistically significantversusthe suction only group at 1, 3, and 4 h. Surfactant levage of meconium aspiration in piglets results in short-term improvement of oxygenation and warrants further study. (Pediatr Res31: 625–628, 1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSThe effects of a maternal protein-calorie malnutrition during gestation and lactation were analyzed on fetal and postnatal lung growth and maturation, including a surfactant fraction isolated from lung tissue. There was a considerable reduction in body weight and in wet and dry lung weight of malnorished pups. Lung protein and DNA concentrations were similar in both groups except in late gestation (lung hyperplasia) and 2 and 15 d after delovery (hypocellularity). Lung glycogen breakdown was slowed down in malnourished newborns. Surfactant material was decreased the most perinatally and the reduction was more marked than for the nonsurfactant fraction of the lung. Disaturated phosphatidylcholine, the major surface active surfactant component, was decreased the most at birth (1.70 ± 0.31 nmol/mg wet wtversus3.68 ± 0.17 nmol/mg in controls, n = 8) and on d 2 (5.04 ± 0.53 nmol/mgversus7.67 ± 0.44 nmol/mg in controls,n= 8). There was an apparent recovery in the composition of surfactant in malnourished rats 5 d after delivery, due in fact to a decrease in controls, and an actual return to normal levels 15 to 20 d after birth. Postnatal lipid supplementation with Intralipid led to partial recovery on d 10. Inositol supplementation totally reverted the effects of malnutrition on surfactant phospholipids (8.36 ± 0.94 nmol disaturated phosphatidylcholine/mg wet wt on d 2versus7.67 ± 0.44 nmol/mg in controls and 5.55 ± 0.62 nmol/mg in untreated malnourished rats,n= 10; 2.43 ± 0.32 nmol disaturated phosphatidylcholine/mg wet wt on d 10versus3.26 ± 0.32 nmol/mg in controls and 1.18 ± 0.27 nmol/mg in untreated malnourished rats,n= 8). It is concluded that protein-calorie malnutrition profoundly affects surfactant phospholipid biosynthesis in the perinatal period and that inositol may represent a useful additive to the diet of malnourished neonates for the correction of pulmonary abnormalities. (Pediatr Res31: 629–635, 1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSWe investigated the effects of pancuronium bromide pretreatment on cerebral blood flow (CBF) during bicuculline-induced seizures in anesthetized piglets. Arterial blood pressure, gases, pH, cerebral electrocortical activity, and CBF (radioactive microsphere) were monitored at baseline, 10 min after administration of pancuronium (0.3 mg/kg i.v.;n= 9) or vehicle (normal saline;n= 8), and again at 5, 15, and 60 min after bicuculline (3 mg/kg i.v.). No change in CBF from baseline was observed at 10 min after either saline or pancuronium treatment, before induction of seizures. In the saline group, CBF was 36 ± 3 m·min-1·100 g-4before bicuculline and increased to 166 ± 24 and 205 ± 35 m·min-1·100 g-1at 5 and 15 min, respectively, after bicuculline, returning toward baseline by 60 min. In the pancuronium group at 5 min after bicuculline, CBF increased from 45 ± 7 to 169 ± 26 m·min-1·100 g-1, but fell to 88 ± 17 m·min-1·100 g-1at 15 min in contrast to saline-treated piglets. Also, at 15 min of seizures, differences between groups were observed in arterial blood pressure, gases, and pH. Although these variables were in the normal range with pancuronium treatment, the saline-treated animals had increased arterial blood pressure (81 ± 6 mm Hg) and Pco2(6 ± 0.4 kPa) and decreased Po2(7 ± 0.5 kPa) and pH (6.91 ± 0.06). Electrocortical activity was abnormal during seizures in both groups. At 60 min, reversal to normal activity was observed in six of nine pancaronium-treated animalsversustwo of eight saline-treated animals. These data suggest that pancuronium limits cerebral hyperemia during prolonged seizures by attenuating increases in blood pressure as a result of elimination of skeletal muscle activity. This leads to minimal alteration of arterial Pco2, Po2, and pH during seizures. (Pediatr Res31: 636–639,1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

ABSTRACTSWe used a cranial window preparation to observe the effects of direct application of group B streptococci to the surface of the brain in the adult rat. Continuous exposure to group B streptococci at concentrations of 103and 105organisms/mL caused progressive dilation of surface (pial) cerebral arterioles that became statistically significant (p< 0.05) after 2.5 h. These results were reproduced with heat-killed organisms at the same concentration, but not with a bacteria-free filtrate of the growth medium. In separate studies, we found that infusion of alkaline cerebrospinal fluid (pH = 7.8) into the window did not reverse vasodilation, suggesting that it was not due to progressive cerebrospinal fluid acidosis. A solution of nitroblue tetrazolium infused into the window at the end of a 3-h exposure to the organism was promptly reduced, suggesting the presence of oxygen free radicals. Treatment with i.v. polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase in doses of 10 000 and 20 000 U/ kg, respectively, was itself without effect on pial arterioles, but treatment with these compounds before exposure to group B streptococci eliminated the vasodilation. These data support a role for oxygen free radicals in the pathogenesis of pial arteriolar dysfunction induced by exposure to group B streptococci. (Pediatr Res31: 640–644,1992)

ISSN:0031-3998    

出版商:OVID    

年代:1992

数据来源: OVID