摘要:

Naloxone has been shown to reverse the hemodynamic sequelae of experimental septic shock in adult animal models. Its effectiveness in the newborn has not been studied. To further investigate the efficacy of naloxone, we instrumented 18 piglets for continuous measurement of mean arterial pressure, mean pulmonary arterial pressure, central venous pressure, heart rate, left ventricular pressure, contractility, cardiac output, and O2. Oxygen consumption, systemic vascular resistance, and pulmonary vascular resistance were calculated. Following a stabilization period, group B β-hemolytic Streptococci were infused over 30 min. Following the infusion, naloxone (1 mg/kg) was given followed by a continuous infusion of 1 mg/kg/h in nine treatment animals. Nine control animals were given an equal volume of saline. Both groups developed significant increases in mean pulmonary arterial pressure followed by a return to baseline. Oxygen consumption, cardiac output, contractility and mean arterial pressure decreased in both groups. Treatment with naloxone was associated with a cessation in the fall in the mean arterial pressure and the contractility. The difference in mean arterial pressure and contractility between groups was significant. The naloxone group had significantly improved 5–h survival. We speculate that naloxone may reverse some of the hemodynamic sequelae and improve survival in newborns with septic shock.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

<0.001), lysozyme (p=0.006), and IgA (p<0.001) than those of cow's milk formula-fed infants. The concentrations of total and secretory IgA were correlated significantly (r=0.88, p<0.001) and 95% of total IgA was SIgA. The fecal concentration of specific SIgA antibodies to E. coli O antigens in FM-fed infants correlated with the concentration of these antibodies in their milk (p<0.001). However, there were no direct relationships between the milk concentrations or the infants' intakes of the other selected immune factors and the excretion of these factors in the feces. Significant relationships were noted among the immune factors in the feces, but not among the concentrations of these factors in the fortified human milk. The increased quantity of selected immune factors in the feces of very low birth weight infants fed FM may have resulted not only from passive ingestion and persistence of these factors throughout the gastrointestinal tract but also from endogenous synthesis induced by the feeding of human milk.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

It has been suggested that the lower birth weight of newborn infants of mothers who smoke is due mainly to a deficit of lean body mass (LBM). We tested this hypothesis by measuring total body potassium, thus deriving the LBM and fat mass, of newborn infants of mothers who smoked (I-SM; n — 32) or did not smoke (INSM; n=46). Mothers who smoked were significantly younger than nonsmoking ones (25.4 and 28.9 yr, respectively) and with less years of education, but were similar in other parameters examined. The 78 infants, all singleton, were studied within 1 to 3 days of birth. The I-SM had significantly reduced birth weight, length, and head circumference but there was no difference in skinfold thickness. We measured total body potassium with a whole-body counter specially made for use with infants. Mean absolute total body potassium was significantly greater in the INSM, but the concentration in relation to weight was not different. Assuming 1 kg LBM to contain 52.1 mmol potassium, the mean LBM was 3028 g in the I-NSM and 2739 in the I-SM; mean fat mass was similar in both groups. Multiple regression analysis revealed an independent negative effect of mother's smoking on birth weight and LBM. This unequal reduction in LBM indicates a complex effect of smoking, probably mediated by alterations in protein synthesis and adipocyte metabolism. It may relate to the higher morbidity rates in infants of mothers who smoke.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The ability of a serum fraction, mol wt 1000- 5000, to stimulate insulin release in vitro was studied in 123 obese and normal weight children aged 0-17 yr. The sera were fractionated by serial molecular filtration after treatment with urea. Stimulation of insulin release was determined with a bioassay using isolated rat islets in perifusion. The islet-stimulating activity was found in all obese children less than the age of 10 yr and in the majority of the obese children older than 10 yr of age. In normal weight children the activity was also found in the majority of infants, but was infrequent in older children. The serum islet-stimulating activity was positively correlated with the duration and degree of obesity and with linear growth rate. The molecular structure and origin of the insulinogenic activity in the serum is still unknown. In high-performance liquid chromatography it has the same elution characteristics as the hypothalamic insulin-glucagon liberin. The present results suggest a role for the serum islet-stimulating activity in the pathogenesis of obesity.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The response to laryngeal chemoreflex (LCR) water stimulation was compared in unanesthetized awake 4- to 10-day-old preterm and 2- to 4-wk-old term lambs before and after infusion of a β-adrenergic agonist, terbutaline, given pre- and postcarotid body denervation (CBD). Ventilation decreased more in response to LCR stimulation post-CBD in the older lambs. CBD did not change the respiratory response to LCR stimulation in the younger lambs. LCR stimulation resulted in less bradycardia post-CBD in both groups. Terbutaline significantly attenuated the LCR response in the older lambs pre-CBD but not post-CBD. LCR respiratory response was not changed in the younger lambs when terbutaline was infused, pre- or post-CBD. Compared to wakefulness, the LCR response in preterm lambs was greater in sleep not associated with arousal. If arousal occurred, LCR response during sleep did not differ from that during wakefulness. The incidence of arousal decreased markedly after CBD, suggesting that arousal is modified by the carotid bodies. It is concluded that the carotid bodies modify the reflex response to LCR stimulation in 2- to 4-wk-old lambs. During the 1st postnatal wk, preterm Iambs have a reduced carotid body function during wakefulness and, therefore, a decreased hypoxic ventilatory response and increased respiratory response to LCR stimulation. The attenuating effect of terbutaline on LCR response is partially related to mature carotid body function.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

In this study the uterine movement of oxygen, glucose, and lactate was quantitated in the awake late pregnant guinea pig. Mean uterine uptake of oxygen per kg of uterus with conceptus was 581 μmol min-1, which is comparable to the value reported for the awake near-term rabbit, but 30% higher than the value reported for the awake near-term sheep. Experiment-related anemia in some animals was associated with a reduced uterine oxygen uptake. The arteriovenous oxygen difference across the uterus correlated positively with the arterial oxygen content and the hemoglobin concentration and negatively with uteroplacental blood flow. Uterine oxygen uptake showed a positive correlation with both the arterial hemoglobin and the uteroplacental blood flow. Uterine lactate output accounted for 20% of uterine glucose uptake, assuming maternally derived glucose to be the only source for uterine lactate output. After correction for this lactate output, the uterine glucose uptake was 96.5 μmol min-1. kg-1of pregnant uterus. This value is 30% higher than in the awake near-term rabbit and more than twice as high as that in the awake near-term sheep. Nevertheless, because of the high uterine demand for substrates, this uterine glucose uptake could only cover 45% of the caloric requirements of the pregnant uterus. The late pregnant guinea pig fetus may derive as much as 55 % of its caloric uptake for fat deposition and protein accretion. Therefore, it is likely that the nonglucose uterine caloric uptake in the late pregnant guinea pig consists predominantly of fat precursors and amino acids.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

To evaluate immune responses to diphtheria and tetanus toxoids in infants we used enzyme-linked immunosorbent assays to detect total IgG and specific IgG- 1, IgG-2, IgG-3, and IgG-4 antibody. One group of infants received a newborn dose and subsequently received the usual three doses of DTP. A second group of infants received only the routine dosage at 2, 4, and 6 months of age. In sera acquired at birth, 6, and 9 months of age, there were no statistically significant differences between the two vaccine groups in IgG antibody responses to diphtheria or tetanus, or in IgG subclass tetanus-specific antibody responses. In individual children, tetanus-specific subclass responses were similar in pattern to that for total IgG tetanus antibody, i.e. each IgG subclass response appeared to be regulated by similar mechanisms in that child, but the regulation differed between children. In contrast to a prior study of pertussis immunity, maternally acquired antibody did not significantly affect immune responses to diphtheria or tetanus toxoid by 9 months of age. There was no discernible tolerance due to early tetanus or diphtheria immunization or to high levels of maternally acquired antibody.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Because mucosal glucoamylase is most active against glucose polymers less than 10 glucose units in length, longer chain polymers may not be completely absorbed by young infants. In order to investigate this possibility, the absorption and oxidation ofI3C-rich glucose, short-chain (3 to 8 glucose units in length) and long-chain (average length 43 units) glucose polymers (GP) were compared in 12 healthy, 1-month-old infants. Recovery of the GP and glucose in stool was measured by determining theI3C enrichment of stool. The oxidation of the GP was measured by tracing the increase in breath13CO2after GP were fed. Carbohydrate malabsorbed in the small bowel was assessed by measurement of breath H2, a gas formed from the fermentation of carbohydrate in the colon. Analysis of the infants' stools revealed that one infant excreted 9.7% of the dose of glucose, another 6.7% of the dose of short-chain GP, and five infants excreted 2.6 to 18.5% (mean 8.4%) of the dose of long-chain GP. The percent of the administered dose recovered in breath was similar among substrates (mean=28.7% of the dose fed). A rise in breath H2greater than 20 ppm was found in four of the 12 infants after the feeding of glucose, in five of 12 after the short-chain GP, and in six of 12 after the long-chain GP. None of the infants developed diarrhea. The results suggest that healthy young infants do not absorb long-chain GP as completely as they absorb short-chain GP. In the absence of pancreatic amylase, salivary amylase and mucosal glucoamylase are sufficient in some young infants to allow for complete digestion of long-chain GP.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Hydrophobic, small molecular weight, surfactant- associated protein of Mr=6000 (SAP-6) was isolated from bovine, canine, and human alveolar lavage and identified by silver staining after sodium dodecyl sulfate polyacrylamide gel electrophoresis gels. Lesser amounts of protein of Mr=14,000, 20,000, and 26,000 daltons also copurified with SAP-6, likely representing oligomers of the Mr=6,000 dalton protein. In the absence of sulfhydryl-reducing agents, increased amounts of the larger forms of the protein were observed. Antisera generated against bovine SAP-6 were used to further characterize the protein and distinguish it from the more abundant surfactant-associated glycoprotein of Mr=35,000 (SAP- 35) present in mammalian surfactants. Rabbit antisera generated against the bovine hydrophobic protein recognized SAP-6 and lesser amounts of the proteins of Mr=14,000, 20,000, and 26,000 daltons. The SAP-6 antisera were reactive against the hydrophobic proteins from human, bovine, and canine surfactants as assessed by immunoblot analysis after sodium dodecyl sulfate polyacrylamide gel electrophoresis. SAP-6 antisera did not detect bovine SAP-35 the abundant surfactant-associated glycoprotein, by immunoblot analysis; however, some reactivity of the anti-SAP-6 was detected against purified bovine SAP-35 by a sensitive enzyme-linked immune-adsorbant assay. Anti-SAP-6-did not react with bovine serum components either by immunoblot or by enzyme-linked immune- adsorbant assay. Monospecific antisera generated against bovine SAP-35 did not detect SAP-6 by immunoblot analysis. Immunoblot analysis of the protein in exogenous replacement surfactant preparations, Surfactant-TA and calf lung surfactant extract, utilizing anti-SAP-6 and anti-SAP-35 demonstrated that both preparations were enriched in SAP-6 and lacking in SAP-35. Surfactant-associated proteins, present in bovine lung-based replacement surfactants, are immunologically identified as SAP-6 and its oligomers.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Infants with respiratory failure are often ventilated at rates exceeding 60 breath–min–1. To obtain insight into the factors controlling the delivery and distribution of tidal volume at these ventilatory rates, we analyzed the inspiratory and expiratory pressure-flow relationships of the respiratory system and its components (lungs, endotracheal tube, and chest wall) in anesthetized, paralyzed rabbits ventilated at 60, 90, and 120 breath–min–1. Inspiratory times were 0.3,0.2, and 0.1 s. Driving pressure was maintained constant. We expressed the effect of ventilatory rate and flow direction on the pressure-flow relationships as changes in compliance, mean resistance, and inertance. We found a nonlinear pressure-flow relationship in both endotracheal tube and respiratory system. This nonlinearity could be accurately described as a function of gas flow and volume acceleration with similar coefficients for tube and respiratory system. Although the inspiratory and expiratory compliance and the mean inspiratory resistance of the lungs were lower at the higher ventilatory rates, the constant resistive behavior of the endotracheal tube and the constant elastic behavior of the chest wall caused a relatively rate-independent pressure-flow behavior of the respiratory system. The lower inspiratory resistance of the lungs was offset by the higher inspiratory resistance of the endotracheal tube, resulting in the resistance of the respiratory system being independent of the direction of gas flow. The rate-dependency of compliance and inspiratory resistance of the lungs suggests an heterogeneous distribution of inspiratory flow at rapid ventilatory rates. At these ventilatory rates, the high resistance of the respiratory system and the nonlinearity of the pressure-flow relationship decrease the tidal volume delivered to the lungs in a magnitude that can be predicted from the time course of the ventilatory pressure.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID