摘要:

Studies were performed to determine the effects of iron deficiency in the rat on neutrophil activation and on levels of neutrophil myeloperoxidase and cytochromeb. The period of time required for neutrophil activation was not significantly affected by iron deficiency, but the maximum rates of respiration attained after activation were markedly lower (60% decrease) in iron-deficient neutrophils than in control cells. The myeloperoxidase activity of neutrophils from iron-deficient rats was also markedly decreased (approximately 75%) compared with the activity of control cells; however, the concentration of cytochromebin the neutrophils was unaffected by iron deficiency.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Studies performed on iron-deficient and control rats demonstrated that oxidative energy production (phosphorylation) by mitochondria from iron-deficient red and intermediate skeletal muscles was greatly reduced with pyruvate-malate, succinate, and a-glycerophosphate as substrates. Although phosphorylation was also decreased in iron-deficient white skeletal muscle with succinate and pyruvate-malate as substrates, no change was found with a-glycerophosphate as substrate.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Lung injury was induced in young rats by a continuous infusion of hypoxanthine intravenously and breathing 100% oxygen for 48 h (group 1). Control animals were rats infused glucose and breathing 100% oxygen (group 2), rats infused hypoxanthine in room air (group 3), and untreated rats (group 4). In group 1 rats interstitial and alveolar edema was found with a tendency toward marked margination of polymorphonuclear neutrophils in small vessels (P< 0.025 compared with group 2). The main elastase inhibitor alpha,-antitrypsin (α-l-PI) was significantly elevated in group 1; 2-, 3− and 5-fold, respectively, when compared with groups 2, 3, and 4. The surfactant phopholipids from alveolar lavage were normal in all groups. The protein-rich fraction of the lavage fluid from group 1 rats inactivated, however, the surface properties of lung surfactant. Minimum surface tension in group 1 rats was 14.5 dyn/cm compared with 7.0 dyn/cm in group 2, 2.9 dyn/cm in group 3 and 3.5 dyn/cm in group 4 (P < 0.05, group 1 and 2versus4). We conclude that the combination of hypoxanthine and high levels of oxygen causes lung injury, possibly via free oxygen radicals. We discuss the possibility that these findings demonstrate a basic pathogenetic mechanism for the hypoxic-hyperoxic insult and can contribute to the understanding of pathogenesis of a variety of diseases both in pediatrics and adult medicine.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The impact of malnutrition on peptide and amino acid absorption has been studied in the immediate postweaning period. At this time peptide uptake is quantitatively more important than amino acid uptake and the vulnerability of the infant to malnutrition is great. Everted rings of rat jejunum were used to investigate the uptake of the peptide glycylsarcosine (Gly-Sar) and the amino acid L-leucine. The animals had been weaned on to isocaloric diets containing 18% or 4% protein. The rats deprived of protein at this age showed a marked growth disturbance with considerable reduction in gut length in addition to poor weight gain. Mediated influx of Gly-Sar and leucine per centimeter of jejunum was reduced in the malnourished animals: Vmax, 77 ± 7.1 (SEM) and 65 ± 3.6 compared with 85 ± 10.6 and 77 ± 4.4 nmol · min-1· cm-1., respectively. But, when expressed in relation to body weight, the maximal transport capacity showed a marked increase with malnutrition, values being 126 and 111 nmol-1, cm-1.100 g-1body weight compared with 39 and 35 nmol-1. cm-1.100 g-1body weight for Gly-Sar and leucine respectively.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

We identified isovaleryl glucuronide in the urine of patients with isovaleric acidemia by using gas chromatography-mass spectrometry (GC-MS) and by identifying the products of enzymatic hydrolysis. Conjugation of isovaleryl-CoA with glycine, by the action of glycine-N-acylase, is the main detoxification mechanism in isovaleric acidemia. The identification of isovaleryl glucuronide demonstrates a hitherto unknown, additional detoxification mechanism in patients with isovaleric acidemia. Quantitative analysis of 72 urine specimens from four patients with isovaleric acidemia shows that isovaleryl glucuronide is more likely to be excreted when the amount of urinary 3-hydroxyisovaleric acid excretion is high. This suggests that detoxification via glucuronide conjugation plays an important role when the glycine conjugation system is saturated.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

To evaluate the role of artificial feeding and natural feeding in early growth of enteric mucosa, we determined enteric mucosal mass, protein and DNA content, and disaccharidase activities in beagle puppies at birth, and after 24 h of either natural or artificial feeding. Despite similar increases in body weight over the first 24 h of life, neither mucosal mass, DNA content, nor protein content of the artificially fed animals was different from that of newborn animals. In contrast, mucosal mass of the suckled animals was 75% greater, DNA content was 56% greater, and protein content was 93% greater than that of newborn animals. The mucosal protein/DNA ratio of the suckled animals was greater than that of newborn, but not artifically fed animals. The greater DNA, protein, and protein/DNA ratio in this group suggest that the greater mucosal mass is a result of both cellular hyperplasai and hypertrophy. Sucrase specific activity of the suckled animals was less than that of the artificially fed but not the newborn animals. Other disaccharidase activities were not different among the three groups.These data extend the findings of Widdowsonet al.(25) to another species and demonstrate that this rapid enteric growth over the first day of life results only from natural feeding. They strongly suggest, therefore, that rapid early enteric growth, mediated perhaps by a factor in natural milk that stimulates enteric mucosal growth, is an important heretofore unappreciated phase of intestinal development.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

A child presented with obstructive sleep apnea (OSA) and near-fatal airway obstruction and respiratory arrest shortly after receiving chloral hydrate (CH). We, therefore, hypothesize that CH might selectively depress upper airway maintaining muscles such as the genioglossus and so predispose to airway obstruction.Genioglossus (GG) and diaphragmatic (DIA) integrated electromyograms (I EMGs) were recorded in four cats and four rabbits before and after hypnotic doses of CH ranging from 200–1000 mg/kg. Results were similar in both species. Peak GG EMG decreased within 10–20 min after CH in seven of eight animals. Average peak GG I EMGs were decreased from 100% before CH to as low as 37.0 ± 27.2% (SD) after CH (P c 0.001). Minimum GG 1 EMGs fell from 47.2 ± 27.2% of peak values before CH to as low as 16.0 ± 9.7% after CH (P < 0.01). Phasic GG I EMGs decreased from 53.8 ± 25.1% of peak control activity to as low as 20.6 ± 24.6% after CH (P < 0.05). By contrast, peak and phasic DIA I EMGs after CH were not significantly different from those before CH administration. We conclude that hypnotic doses of CH may preferentially depress GG activity as compared with DIA activity. Selective depression of airway-maintaining muscular contraction by CH may place susceptible patients at risk for life-threatening airway obstruction and may preclude the use of CH to facilitate sleep for polygraphic evaluations in patients suspected of having OSA.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Patency of the ductus arteriosus in preterm infants is mediated by vasodilating prostanoids; however, reliable methods to monitor prostanoid activity or production in preterm infants are lacking. We measured the excretion rates of major and characteristic urinary metabolites of prostacyclin (PGI2), PGE1and PGE2, 6-keto-PGF1α, and 7α-hydroxy-5,11-diketotetranorprostane-1,16-dioic acid (PGE-M), respectively. Besides these parameters which reflect total body prostanoid turnover and production, the urinary levels of PGE2and PGF2α, the primary prostaglandins, were measured as an index of renal prostanoid synthesis. There were four study groups. One contained 11 thriving preterm infants; a second, six preterm infants with respiratory distress syndrome (RDS); a third, 30 preterm infants with RDS and patent ductus arteriosus (PDA); and a fourth, nine fullterm infants. All infants with RDS required artificial ventilation. There were no significant differences in PGE-M, PGE2and PGF2αexcretion rates among the various groups; however, a significant increase of the 6-keto-PGF1αexcretion rates was observed in the groups of infants with RDS and with and without PDA (P < 0.01 and P < 0.02, respectively). Spontaneous (n = 2) or indomethacin-induced (n = 6) closure of PDA was associated with weaning from the respirator and a concomitant drop into the normal and subnormal range of the excretion rates of 6-keto-PGF1, (P < 0.01) and PGE-M (P < 0.02).

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Total body water was measured by H218O stable isotope dilution in two groups: in premature infants without complications, who were studied from 8 d of age until discharge; and in Peruvian subjects aged 6–36 mo, who were in the long-term convalescent stage of recovery from malnutrition. Results indicated that reliable total body water estimates can be obtained from sample volumes as small as 50μl of urine or plasma using a gas-isotope-ratio mass spectrometer equipped with an automated purification inlet system. Results from 21 studies in 10 Peruvian infants indicated substantially completed isotope equilibration in plasma by 2 h after the dose; total body water estimates from the 2-h samples averaged 98.7%(±4.1) of 6-h values. Samples obtained at 4-h postdose gave total body water estimates that averaged 99.0% (± 2.9) of the 6-h value, showing essentially complete equilibration and reduced variability. Total body water estimates from urine samples collected 3–5 h postdose were closely correlated with 6-h, plasma-based total body water values in both premature and older infants; however, some reduction in variability was observed when urine collection was extended to 5–7 h, at which time urine-based estimates averaged 98.8%(±2.0) and 100.7% (±3.1) of plasma-based values for prematures and older Peruvian infants, respectively. The correlation between 5–7 h urine-based estimates of total body water with plasma-based values was r = 0.96 for 30 studies in prematures and r = 0.99 for 57 studies in older Peruvian infants. Data points adhered closely to the lines of identity in both study groups. These results suggest that noninvasive urine sampling techniques can be substituted for plasma sampling in body water studies in infants.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Infusion of gastrin, G-171, at 0.4 μg/min into either the maternal or fetal venous circulation of six late gestation sheep was associated with increases in serum gastrin concentration in the infused circulation and reciprocal decreases in the serum gastrin concentration in the other circulation (contraplacental) that perfused the placenta. Pentagastrin infusion at 0.4 μg/min was associated with an increase in C-terminal specific gastrin immunoreactivity in both the infused and the contraplacental circulations. These observations suggest that biologically active fragments of gastrin, but not the intact molecule, may cross the ovine placenta. An alternative explanation for our results is that gastrin infusion into either the maternal or fetal circulation which perfuses the placenta may result in the release of an inhibitor (ie., somatostatin) into the other circulation. Of broad importance, these observations indicate that although intact polypeptide hormones may not traverse the placenta, their concentrations in maternal and fetal sera may not be as independent as previously believed. Serum gastrin half-life values in late gestation sheep fetuses, lambs, and ewes were determined to be 13.7 ± 1.9, 16.7 ± 2.6, and 15.2 ± 2.8 min, respectively. These similar values indicate that the relatively high serum gastrin concentrations observed in near-term sheep fetuses are not the result of pro-longed half-life in the fetus.

ISSN:0031-3998    

出版商:OVID    

年代:1984

数据来源: OVID