Neonatal hypoxia triggers transient apoptosis followed by neurogenesis in the rat CA1 hippocampus

Continuous generation of new neurons has been demonstrated in the adult mammalian brain, and this process was shown to be stimulated by various pathologic conditions, including cerebral ischemia. Because brain oxygen deprivation is particularly frequent in neonates and represents the primary event of asphyxia, we analyzed long-term consequences of transient hypoxia in the newborn rat. Within 24 h after birth, animals were exposed to 100% N(2) for 20 min at 36 degrees C, and temporal changes in the vulnerable CA1 hippocampus were monitored. Cell density measurements revealed delayed cell death in the pyramidal cell layer reflecting apoptosis, as shown by characteristic nuclear morphology and expression levels of Bcl-2, Bax, and caspase-3. Neuronal loss was confirmed by reduced density of neuron-specific enolase (NSE)-labeled cells, and peaked by 1 wk post insult, to reach 27% of total cells. A gradual recovery then occurred, and no significant difference in cell density could be detected between controls and hypoxic rats at postnatal d 21. Repeated injections of bromodeoxyuridine (50 mg/kg) showed that newly divided cells expressing neuronal markers increased by 225% in the germinative subventricular zone, and they tended to migrate along the posterior periventricle toward the hippocampus. Therefore, transient hypoxia in the newborn rat triggered apoptosis in the CA1 hippocampus followed by increased neurogenesis and apparent anatomical recovery, suggesting that the developing brain may have a high capacity for self-repair.     

Neonatal hypoxia or maternal diabetes delays postnatal development of liver mitochondria

The matrix adenine nucleotide pool size of rat liver mitochondria was low at birth (2.6-3.0 nmol ATP + ADP + AMP/mg mitochondrial protein). After parturition, the pool size was increased by 50-75% within 1 h, which was sufficient for full development of state 3 respiration rates. The adenine nucleotide pool size continued to increase to 100-150% of the value at birth by 2-3 h postnatal. The ATP/ADP ratio in isolated mitochondria also increased postnatally, to about double the value at birth by 3 h. There were no matrix volume changes over this postnatal period, so the increased ATP + ADP + AMP pool size and the increased ATP/ADP ratio together inferred an overall increase of about 5-fold in the matrix ATP concentration under aerobic conditions. The postnatal uptake of adenine nucleotides into mitochondria occurred at a slower rate in newborns that were hypoxic (11% 02) and in newborns of diabetic mothers (diabetes induced on day 5 of gestation by streptozotocin injection). The normal increase in matrix ATP content is responsible for the rapid stimulation of pyruvate carboxylation (an ATP-requiring matrix reaction) and this in turn contributes to the rapid postnatal onset of gluconeogenesis. The results suggest that delayed adenine nucleotide uptake into liver mitochondria may retard initiation of gluconeogenesis in newborns experiencing hypoxia, as in respiratory distress or in newborns of diabetic mothers. We speculate that this mechanism contributes to the persistent hypoglycemia that is typical of these at-risk newborns.     

Congenital pancreatic hypoplasia: a syndrome of exocrine and endocrine pancreatic insufficiency

We describe two brothers with small size at birth, early-onset insulin-dependent diabetes, and pancreatic exocrine insufficiency. In contrast to the findings in pancreatic aplasia, their serum C-peptide and glucagon levels were measurable. These findings, in concert with their clinical courses, are consistent with the diagnosis of congenital pancreatic hypoplasia.     

Wolcott-Rallison syndrome: a case with endocrine and exocrine pancreatic deficiency and pancreatic hypotrophy

Clinical analysis and genetic investigations of new cases of Wolcott-Rallison syndrome are needed to evaluate the role of the gene(s) directly or indirectly implicated in pancreas development and in the aetiology of the syndrome.     

Decline of exocrine pancreatic function in cystic fibrosis patients with pancreatic sufficiency.

Patients with cystic fibrosis and pancreatic sufficiency were investigated for evidence of progressive pancreatic disease. From a cohort of 630 patients, 20 pancreatic-sufficient patients became pancreatic insufficient after an average duration of 5.6 y (range 0.6-20.6 y) from diagnosis. Among 54 patients documented to be pancreatic sufficient by direct pancreatic stimulation test, 47 remained pancreatic sufficient and seven developed pancreatic insufficiency. The patients who ultimately developed pancreatic insufficiency were younger and had greatly reduced outputs of enzyme, fluid, and electrolytes. Those who remained pancreatic sufficient showed enzyme secretion close to or within the non-cystic fibrosis control range. Twenty of these patients underwent a second pancreatic stimulation test after an average interval of 4 y (range 1.3-6.2 y). No significant alteration in enzyme, fluid, or electrolyte output was seen in the patients who remained pancreatic sufficient, but there was further reduction in enzyme and fluid output in the patients who developed pancreatic failure. In conclusion, the majority of pancreatic-sufficient patients with pancreatic enzyme secretion within the control range showed no deterioration of function over an extended time period. However, a small number of pancreatic-sufficient patients with reduced enzyme and fluid secretion are at risk of pancreatic failure.     

Faecal chymotrypsin: a reliable index of exocrine pancreatic function.

Simultaneous measurements of duodenal and faecal chymotrypsin were made in 30 children aged 3 weeks to 14 years. Apparent chymotrypsin secretion rates measured after stimulation with pancreozymin were compared with the mean faecal chymotrypsin concentration derived from three stool specimens collected at random within 72 hours of the intraduodenal test. In the 25 children who responded to pancreozymin stimulation the mean faecal chymotrypsin concentration was significantly positively correlated with the apparent chymotrypsin secretion rate. Correlation using single specimen stools collected at random was appreciably poorer. In the five children with undetectable or only traces of chymotrypsin in the duodenum after stimulation, the mean faecal chymotrypsin concentrations were only 3-10% of the lower limit of the reference interval. In a second group of 46 children with cystic fibrosis proved by sweat tests and clinical evidence of malabsorption, the chymotrypsin concentration measured in a single stool specimen collected at random was unequivocally subnormal in each case. Faecal chymotrypsin measurement is a rapid, simple, cheap, readily repeated, non-invasive test of high specificity and sensitivity. Faecal chymotrypsin should be measured before contemplating intraduodenal tests of pancreatic function.     

Value of isoamylases in the diagnosis of exocrine pancreatic insufficiency in childhood

Pancreatic- (P) and salivary-like (S) isoenzyme concentrations were measured in 64 healthy children and 44 patients with cystic fibrosis (CF) the most frequent cause of exocrine pancreatic insufficiency in childhood. The isoamylases were determined by means of an established method, the isoelectric focusing (IEF) and by a recently described inhibitory test, the Phadebas-Isoamylase test (PIT). Serum isoamylase levels were age dependent during the first 16 months of life. In healthy infants as well as in patients with CF up to 16 months of age P type amylase concentrations were very low and of no diagnostic value whereas S type amylase was 4-fold increased in the CF-group. CF-patients older than 1 year and 4 months showed pathologically diminished P type amylase levels in 86% (IEF) or 70% (PIT) resp. Further investigations as well as clinical findings revealed a normal pancreatic function in 5 patients (= 14%) with normal P type concentrations in both tests. Thus an exocrine pancreatic insufficiency could be diagnosed by means of lowered P type amylase in all (IEF) resp. 81% (PIT) of our patients. The specificity of the tests with regard to P type amylase amounted to 1 for IEF and 0.98 for PIT.     

Neonatal hypoxia and pulmonary vasospasm: response to tolazoline.

Forty-six neonates with hypoxemia were treated with tolazoline, a pulmonary vasodilator, within the first two days of life. Eight of ten (80%) infants without apparent lung disease responded with a mean increase in PaO2 of 116 torr within one hour of beginning tolazoline infusions. One of the responding infants and two nonresponders died. Thirty-six additional infants with a variety of pulmonary disorders had severe hypoxemia which was refractory to mechanical ventilation. Twenty-one (58%) responded with a mean increase in PaO2 of 130 torr within one hour after beginning tolazoline and 13 (62%) of these survived. Fifteen patients had little or no improvement in PaO2 following tolazoline and only three (20%) of these infants survived. Responders could not be distinguished from nonresponders by clinical or laboratory features prior to therapy with tolazoline. Fourteen infants experienced complications possibly related to tolazoline.     

Effect of exocrine pancreatic function on resting energy expenditure in cystic fibrosis

AIM: To prove the hypothesis that exocrine pancreatic function determines resting energy expenditure (REE) in cystic fibrosis (CF). METHOD: Thirty-eight CF individuals, 9-34 (19.98 +/- 1.0) years, were divided into three groups: Six pancreatic sufficient patients (PS; group A), 21 pancreatic insufficient patients (PI), whose pulmonary function was comparable to that of group A (group B1) and 11 PI patients, whose pulmonary function was significantly worse than that of group A (group B2). REE was estimated by indirect calorimetry. Predicted REE was based on Schofield equations. Measured REE was expressed as % of the predicted. BMI, BMI z-scores, serum albumin, cholesterol and triglycerides levels were related to REE. Results were expressed as mean +/- standard error. RESULTS: Groups B1 and B2 had significantly higher REE% (111.7 +/- 2.75% and 119.94 +/- 3.8, respectively) as opposed to group A (98.9 +/- 3.81%; p = 0.022 and 0.035, respectively) whose REE% was similar to that predicted. REE% between group B1 and B2 was not statistically significant. In groups A, B1 and B, mean FEV1% was 86.33 +/- 10.1%, 90.24 +/- 4.39%, 44.54 +/- 3.47%, respectively, mean BMI was 25.6 +/- 2.06, 19.48 +/- 0.64 and 20.09 +/- 8.8, respectively, BMI z-scores were 0.75 +/- 0.51, -0.52 +/- 0.24 and -1.07 +/- 0.37, respectively. Significant correlation was demonstrated between REE%, BMI z-scores and cholesterol levels in group A. CONCLUSION: Clinically stable CF patients, who had comparable pulmonary function, exhibited increased REE% only in the presence of exocrine pancreatic insufficiency. REE% strongly correlated with BMI z-scores in pancreatic sufficiency. These findings support the hypothesis that pancreatic rather than pulmonary function may determine nutritional status as well as REE in CF.     

Chronic hypoxia and rat lung development: analysis by morphometry and directed microarray

It is unclear how sublethal hypoxia affects lung development. To investigate the effects of chronic hypoxia on postnatal lung remodeling, we treated neonatal rats with FIO2 of 0.12 for 10 d and analyzed lung development by morphometry and gene expression by DNA microarray. Our results showed the neonatal rats exposed to hypoxia reduced body weight by 42% and wet lung weight by 32% compared with the neonatal rats exposed to normoxia. In the neonatal rats exposed to hypoxia, the radial alveolar counts were decreased to 5.6 from 7.9 and the mean linear intercepts were increased to 56.5 mum from 38.2 mum. In DNA microarray analysis, approximately half of probed genes were unknown. Chronic hypoxia significantly regulated expression of genes that are involved in pathogenesis of pulmonary hypertension and postnatal lung remodeling. Chemokine ligand 12, jagged 2 were among those upregulated; c-kit, ephrin A1, and Hif-2alpha were among those downregulated. The altered expression of those genes was correlated with the lung development and remodeling.     

Determination of exocrine pancreatic function in childhood with the pancreozymin-secretin test]

Pancreatic function can only be determined exactly via the pancreozymin-secretin test. We conducted this test in two versions: (1) under conditions of continuous perfusion with the possibility of volume correction and (2) as a simple tubing. We compared the results of 86 tubings with the results of 87 examinations under perfusion. For that purpose all patients were classified into four groups: group a) with 46 and 10 examinations, respectively, in patients suffering from cholestasis in early infancy, group b) with 7 and 12 examinations, respectively, in older patients with liver diseases, group c) with 8 and 17 examinations, respectively, in patients suffering from cystic fibrosis or Shwachman's syndrome and group d) with 25 and 48 examinations, respectively, in children with normal pancreatic function. Both examination methods nearly identical mean values of the enzyme activities in all four patient groups. However, mean variations were found to be higher in case of tubing. Therefore the lower limits (x - 2s) of this test were defined at a lower level than those of the tests under perfusion.     

Prenatal ethanol administration: effects on IgG absorption during postnatal development in the rat intestine

The effect of feeding 1 ml of 30% ethanol to pregnant female rats during gestation on the IgG absorption has been studied in the developing intestine. Pups born to dams fed ethanol during gestation exhibited a significant decline in body weight (p < 0.01), intestinal weight (p < 0.01), and intestinal length (p < 0.05) as compared with the controls. Intestinal weight to body weight or intestinal weight to intestinal length ratios were essentially similar under these conditions. The intestinal absorption of IgG was considerably reduced in 12-day-old pups (p < 0.01) exposed to ethanol in utero as compared with the control group. A similar decrease in the binding of [(125)I]IgG to microvillus membranes was observed on days 12 and 20 under these conditions. Northern blot analysis revealed low levels of mRNA encoding IgG Fc receptor in ethanol-exposed pups as compared with the controls. These findings suggest that prenatal ethanol ingestion impairs the absorption of IgG as a consequence of the downregulation of IgG Fc receptor expression in the rat intestine.