Neurodevelopmental outcomes among extremely premature infants with linear growth restriction

OBJECTIVE

To compare neurodevelopmental outcomes in linear growth-restricted (LGR) infants born <29 weeks with and without weight gain out of proportion to linear growth.

STUDY DESIGN

We compared 2-year neurodevelopmental outcomes between infants with and without LGR and between LGR infants with and without weight gain out of proportion to linear growth. The outcomes were Bayley-III cognitive, motor, and language scores, cerebral palsy, Gross Motor Function Classification System (GMFCS) level ≥ 2, and neurodevelopmental impairment.

RESULT

In total, 1227 infants were analyzed. LGR infants were smaller and less mature at birth, had higher BMI, and had lower Bayley-III language scores (82.3 vs. 85.0, p < 0.05). Among infants with LGR, infants with high BMI had lower language scores compared with those with low-to-normal BMI (80.8 vs. 83.3, p < 0.05), and were more likely to have GMFCS level ≥2 and neurodevelopmental impairment.

CONCLUSION

Among infants with LGR, weight gain out of proportion to linear growth was associated with poorer neurodevelopmental outcomes.

Neonatal Acute Kidney Injury: A Survey of Neonatologists' and Nephrologists' Perceptions and Practice Management

BACKGROUND

Neonatal acute kidney injury (AKI) occurs in 40 to 70% of critically ill neonatal intensive care admissions. This study explored the differences in perceptions and practice variations among neonatologists and pediatric nephrologists in diagnostic criteria, management, and follow-up of neonatal AKI.

METHODS

A survey weblink was emailed to nephrologists and neonatologists in Australia, Canada, New Zealand, India, and the United States. Questions consisted of demographic and unit practices, three clinical scenarios assessing awareness of definitions of neonatal AKI, knowledge, management, and follow-up practices.

RESULTS

Many knowledge gaps among neonatologists, and to a lesser extent, pediatric nephrologists were identified. Neonatologists were less likely to use categorical definitions of neonatal AKI (p < 0.00001) or diagnose stage 1 AKI (p < 0.00001) than pediatric nephrologists. Guidelines for creatinine monitoring for nephrotoxic medications were reported by 34% (aminoglycosides) and 62% (indomethacin) of respondents. Nephrologists were more likely to consider follow-up after AKI than neonatologists (p < 0.00001). Also, 92 and 86% of neonatologists and nephrologists, respectively, reported no standardization or infrastructure for long-term renal follow-up.

CONCLUSION

Neonatal AKI is underappreciated, particularly among neonatologists. A lack of evidence on neonatal AKI contributes to this variation in response. Therefore, dissemination of current knowledge and areas for research should be the priority.

Sensitivity of the ultrasonic interferometry method (Echo-Cell) to changes of red cell aggregation: application to diabetes

The sensitivity of the ultrasonic interferometry method (Echo-Cell) to changes in red blood cell (RBC) aggregation was investigated in comparison to the Regulest erythroaggregometry known as a reference method. In experiments where different concentrations of dextrans of 40 or 70 kD molecular weights were added to normal RBCs, the Echo-Cell was proved as sensitive as erythroaggregometry. A comparative study using RBC samples from normal and diabetic subjects showed that the Echo-Cell was much more sensitive when aggregation was measured in diluted than undiluted plasma. The sensitivity of Echo-Cell measurements in diluted plasma was similar to that of erythroaggregometry. Further analysis revealed that RBC aggregation was underestimated by Echo-Cell when measurements were made in undiluted plasma containing high fibrinogen levels, implying that in that case an elevated plasma viscosity might indirectly affect the sensitivity of the Echo-Cell. The low sensitivity of the Echo-Cell to detect an abnormal RBC aggregation when suspensions were prepared in undiluted plasma, is likely related to a relatively high shear stress exerted on RBC aggregates by the suspending medium. In conclusion, the sensitivity of the Echo-Cell to detect abnormal changes in RBC aggregation can be optimized by diluting the plasma.

Bilirubin and serial auditory brainstem responses in premature infants

OBJECTIVES

To determine the usefulness of the bilirubin-albumin (B:A) molar ratio (MR) and unbound bilirubin (UB) as compared with serum total bilirubin (TB) in predicting bilirubin encephalopathy as assessed by auditory brainstem responses (ABR) in infants of 28 to 32 weeks' gestational age.

STUDY DESIGN

During a 2-year period, serial ABRs were obtained on 143 infants of 28 to 32 weeks' gestational age during the first postnatal week. Waveforms were categorized on the basis of response replicability and the presence of waves III and V. Wave V latencies were also serially analyzed when measurable for individual infants. Maturation of the ABR was defined as abnormal when the waveform category worsened and/or latency increased during the study interval. Serum albumin was analyzed at 48 to 72 hours of age in all patients. Serum TB was analyzed as clinically indicated. Aliquots of the same samples were also analyzed for UB in a subset of infants.

RESULTS

The mean peak TB concentration (10.1 +/- 1.7 mg/dL) for the 71 infants with normal ABR maturation was not significantly different from the mean peak TB (10.2 +/- 2.1 mg/dL) in the 24-hour period preceding the ABR's first showing abnormal maturation in the other 55 infants. However, in infants with UB analyzed, the mean peak UB (0.62 +/- 0.20 vs 0.40 +/- 0.15 microg/dL) was significantly higher in the infants with abnormal maturation (n = 25) than in infants with normal maturation (n = 20). The B:A MR results were equivocal. In the entire study population, there was no difference in B:A MR between infants with normal versus abnormal ABR maturation. However, in the subset of infants in whom UB was measured, although TB was not different, there was a significant difference in B:A MR. Based on receiver-operating characteristic curves, a UB level of 0.5 microg/dL was the best discriminator with a sensitivity of 70% and a specificity of 75%. The proportion of infants who had UB >0.5 microg/dL and UB </=0.5 microg/dL and who had abnormal ABR, maturation was 0.81 and 0.33, respectively, with a significant difference in the incidence of transient bilirubin encephalopathy among these 2 groups. The relative risk of abnormal ABR maturation with UB >0.5 microg/dL compared with UB </=0.05 microg/dL was 2.45 (95% confidence interval: 1.33-4.49).

CONCLUSIONS

UB is a more sensitive predictor than either serum bilirubin or B:A MR of abnormal ABR maturation, and hence transient bilirubin encephalopathy in premature newborns with hyperbilirubinemia.

Electrographic seizures in neonates correlate with poor neurodevelopmental outcome

OBJECTIVE

To quantify the number, duration, and intensity of electrographic seizures (ESz) in neonates and to compare the outcome of neonates with ESz with those who were at risk but did not have ESz recorded.

METHODS

The EEG and outcome data were reviewed from 68 infants who met at-risk criteria for neonatal seizures and underwent prolonged continuous EEG monitoring. Forty infants had ESz. The control group contained 28 infants monitored for at least 18 hours and found not to have ESz. Outcomes for both groups were evaluated using hospital and follow-up clinic records and a standardized telephone interview.

RESULTS

The etiology of ESz included asphyxia (n = 23), stroke (n = 7), and other (n = 10, intraparenchymal, subdural, and subarachnoid bleeding; meningitis; sepsis; hyponatremia; and unknown). The cumulative recorded ESz duration was 8 minutes to 30 hours. Forty-three percent of infants with ESz spent 38 minutes to 32 hours in electrographic status. Despite doses of 40 mg/kg of phenobarbital and 20 mg/kg of phenytoin, 30% of infants continued to have ESz. Ten infants with ESz and one without died from causes related to neurologic instability. The occurrence of ESz was correlated with microcephaly (p = 0.04), severe cerebral palsy (CP) (p = 0.03), and failure to thrive (p = 0. 03). In the subgroup of infants with asphyxia, those with ESz were more likely to die of neurologic causes (p = 0.02) and have microcephaly (p = 0.05) or severe CP (p = 0.04). Additionally, those with the greatest number of ESz were more likely to have these severe outcomes.

CONCLUSION

The authors' data indicate an association between the amount of electrographic seizure activity and subsequent mortality and morbidity in at-risk infants in general and in infants with perinatal asphyxia. Only with more effective treatment of neonatal electrographic seizures can their potential contribution to poor neurodevelopmental outcome, independent of degree of insult, be ascertained.

Brainstem maturation in premature infants as a function of enteral feeding type

OBJECTIVE

To determine whether brainstem maturation as measured by brainstem auditory-evoked responses (BAERs) in preterm infants is a function of dietary intake.

STUDY DESIGN

We obtained serial BAERs on infants 28 to 32 weeks' gestation at birth, cared for in the neonatal intensive care unit of a regional referral center in Upstate New York. Waveforms were analyzed for replicability and for the presence of waves III and V. Absolute and interwave latencies were measured. Baseline and follow-up BAER measurements were compared, and the rates of change were calculated. Patient charts were reviewed for type of enteral feeding during the interval between BAERs. Student's t test was used to analyze continuous variables and chi(2) analysis was used to analyze categorical variables.

RESULTS

Data from 37 study infants (17 fed breast milk and 20 fed commercial premature formula) revealed that there was no difference in absolute latencies of waves III and V at baseline; however, the rates of decrease of absolute latencies over the study interval were significantly greater in infants receiving human milk.

CONCLUSIONS

Infants fed breast milk have faster brainstem maturation, compared with infants fed formula, based on the rate of maturation of BAERs. This effect may be attributable to the constituent composition of breast milk, compared with synthetic formulas.

Early dexamethasone-attempting to prevent chronic lung disease

BACKGROUND

We previously demonstrated improved survival and early outcomes in a pilot trial of 2 doses of intravenous dexamethasone for infants with surfactant-treated respiratory distress syndrome. (1) A multicenter, randomized, double-blind trial was undertaken to confirm these results.

METHODS

Infants <30 weeks' gestation were eligible if they had respiratory distress syndrome, required mechanical ventilation at 12 to 18 hours of age, and had received at least 1 dose of exogenous surfactant. Infants were excluded if sepsis or pneumonia was suspected or if congenital heart disease or chromosomal abnormalities were present. A total of 384 infants were enrolled-189 randomized to dexamethasone (.5mg/kg birth weight at 12-18 hours of age and a second dose 12 hours later) and 195 to an equal volume of saline placebo.

RESULTS

No differences were found in the dexamethasone versus placebo groups, respectively, regarding the primary outcomes of survival (79% vs 83%), survival without oxygen at 36 weeks' corrected gestational age (CGA; both 59%), and survival without oxygen at 36 weeks' CGA and without late glucocorticoid therapy (46% vs 44%). No significant differences between the groups in estimates from Kaplan-Meier survival analyses were found for median days on oxygen (50 vs 56 days), ventilation (20 vs 27 days), days to regain birth weight (15.5 vs 14 days), or length of stay (LOS; 88 vs 89 days). Infants given early dexamethasone were less likely to receive later glucocorticoid therapy for bronchopulmonary dysplasia during their hospitalization (27% vs 35%). No clinically significant side effects were noted in the dexamethasone group, although there were transient elevations in blood glucose and blood pressure followed by a return to baseline by study day 10. Among infants who died (40 vs 33), there were no differences in the median days on oxygen, ventilation, nor LOS. However, in survivors (149 vs 162), the following were observed: median days on oxygen 37 versus 45 days, ventilation 14 versus 19 days, and LOS 79 versus 81 days, for the dexamethasone versus placebo groups, respectively.

CONCLUSIONS

This dose of early intravenous dexamethasone did not reduce the requirement for oxygen at 36 weeks' CGA and survival was not improved. However, early dexamethasone reduced the use of later prolonged dexamethasone therapy, and among survivors, reduced the median days on oxygen and ventilation. We conclude that this course of early dexamethasone probably represents a near minimum dose for instituting a prophylactic regimen against bronchopulmonary dysplasia.

Covalent binding of polyethylene glycol to the surface of red blood cells as detected and followed up by cell electrophoresis and rheological methods

Cyanuric chloride activated polyethylene glycol (PEG)-5000 was covalently coupled to murine and human red blood cells (pegylated RBC). Our purpose was to camouflage RBC receptors, which is necessary for parasite invasion, a process essential to sustain parasitemia. Cell electrophoretic mobility analysis (CEM) of pegylated RBC distinguished a new population of cells bearing characteristic CEM. Pegylation of RBC also modified their rheological properties, which were documented by evaluation of cell deformability (based on cell transit time through calibrated micropores) and cell aggregation (as measured by ultrasonic interferometry). Homologous transfusion of pegylated RBC into murine malaria-infected mice had no significant effect on the cerebral malaria death rate in Plasmodium berghei-infected mice, but it reduced the peripheral blood parasitemia by a factor 2 while in Plasmodium yoelii infected mice, the parasitemia was dramatically reduced by a factor of 4. These experiments demonstrate that transfusion of pegylated RBC may inhibit peripheral parasitemia. Cell electrophoresis appears to be a useful tool to allow in vivo detection and to investigate the fate of transfused pegylated RBC.

Morphological changes in serial auditory brain stem responses in 24 to 32 weeks' gestational age infants during the first week of life

OBJECTIVE

The purpose of this investigation was to describe and quantify the sequential morphological changes in the auditory brain stem response (ABR) during the first postnatal week of life in very premature infants < or = 32 wk gestational age. These normative data could be useful in predicting neurological outcome in infants with perinatal risk factors.

DESIGN

Sequential ABRs were recorded on a total of 135 infants on 5 out of the first 7 days of life. For analysis, data were grouped by gestational age in 2 wk intervals. In addition, a unique system was devised to categorize waveform response types in premature infants: type 1, a response with normal morphology and replicable waves III and V; type 2, a replicable response with either a wave III or wave V; type 3, a replicable response with neither a wave III or wave V; type 4, a response with no replicable waveform.

RESULTS

The frequency of detection of waves improves over the first week of life with the detectability of waves III and V being more frequent than wave I at all gestational ages. There was a gradual improvement in response types in infants > 26 wk with the greatest improvement occurring during the 28 to 29 wk gestation. ABRs were predominantly types 3 and 4 at 24 to 25 wk, type 3 at 26 to 27 wk, type 2 at 28 to 29 wk, and types 1 and 2 at 30 to 31 wk. Absolute wave latencies and interwave latencies also progressively decreased during the first postnatal week. In some infants there was a transient increase in latencies or worsening of response type on the second to third test day.

CONCLUSIONS

There is progressive improvement in frequency of detection of waves I, III, and V with increasing gestational age. Response types gradually mature over the first postnatal week, particularly in premature infants 28 to 32 wk gestational age.

Gender, menstrual cycle, oral contraceptives and red blood cell deformability in healthy adult subjects

Gender, menstrual cycle and oral contraceptives may have influence on mechanical properties of Red Blood Cell (RBC) and particularly on RBC deformability. So cell transit parameters have been assessed by filtration with the Cell Transit Analyser (CTA) for a large healthy adult population (seventy-nine males and one-hundred-fifteen females). The CTA provides the distribution of cell transit times of 5000 red blood cells, the mean transit time of the population and different percentiles such as p50, p75, p90 and p95. No effect of oral contraceptives was found. Nevertheless, influence of sex and menstrual cycle were demonstrated. A significant increase of the filtration parameters measured in the female population with respect to the male population and during menstruation, preovulation and post-ovulation periods was observed. During ovulation, the CTA parameters are comparable to the same parameters found in males.

Comparison of two strategies for surfactant prophylaxis in very premature infants: a multicenter randomized trial

INTRODUCTION

Previous trials of surfactant therapy in premature infants have demonstrated a survival advantage associated with prophylactic therapy as an immediate bolus, compared with the rescue treatment of established respiratory distress syndrome. The optimal strategy for prophylactic therapy, however, remains controversial. When administered as an endotracheal bolus immediately after delivery, surfactant mixes with the absorbing fetal lung fluid and may reach the alveoli before the onset of lung injury. This approach, however, causes a brief delay in the initiation of standard neonatal resuscitation, including positive pressure ventilation, and is associated with a risk for surfactant delivery into the right main stem bronchus or esophagus. As an alternative approach, surfactant prophylaxis may be administered in small aliquots soon after resuscitation and confirmation of endotracheal tube position. Although this strategy has substantial logistical advantages in clinical practice, its efficacy has not been established.

OBJECTIVE

The purpose of this study was to determine whether the established benefits of the immediate bolus strategy for surfactant prophylaxis could still be achieved using a postventilatory aliquot strategy after initial standard resuscitation and stabilization.

DESIGN

Multicenter randomized clinical trial with patients randomized before delivery to immediate bolus or postventilatory aliquot therapy.

PARTICIPANTS

Inborn premature infants delivered to mothers at an estimated gestational age of 24[0/7] to 28[6/7] weeks.

INTERVENTIONS

Those infants who were randomized to the immediate bolus strategy were intubated as rapidly as possible after birth, and a 3-mL intratracheal bolus of calf lung surfactant extract (Infasurf) was administered before the initiation of positive pressure ventilation. Those infants who were randomized to the postventilatory aliquot strategy received standard resuscitation measures with intubation by 5 minutes of age, if not required earlier. At 10 minutes after birth, 3 mL of surfactant was administered in 4 divided aliquots of 0.75 mL each. Patients in both groups were eligible to receive up to three additional doses of surfactant as rescue therapy in the neonatal intensive care unit, if needed.

OUTCOME MEASURES

The primary outcome variable was survival to discharge to home. Secondary variables included neonatal complications and requirement for oxygen therapy at 36 weeks' postmenstrual age.

RESULTS

Among three centers, 651 infants were enrolled and randomized before delivery. Survival to discharge to home was similar for the two strategies for surfactant therapy as prophylaxis: 76% for the immediate bolus group and 80% for the postventilatory aliquot group. In a secondary analysis, the rate of supplemental oxygen administration at 36 weeks' postmenstrual age was 18% for the immediate bolus group and 13% for the postventilatory aliquot group.

CONCLUSIONS

Survival to discharge to home was similar with immediate bolus and postventilatory aliquot strategies for surfactant prophylaxis. Because of its logistical advantages in the delivery room and its beneficial effects on prolonged oxygen requirements, we recommend the postventilatory aliquot strategy for surfactant prophylaxis of premature infants delivered before 29 weeks' gestation.

EEG background as predictor of electrographic seizures in high-risk neonates

PURPOSE

Experience with continuous EEG monitoring in 29 consecutive infants at risk of neonatal seizures demonstrated that background abnormalities on the initial EEG were strongly associated with electrographic seizures in the subsequent 18-24 h. To test this association prospectively, we examined the relationship between EEG background and the presence of electrographic seizures in the next 22 at-risk infants monitored for seizures.

METHODS

A standard EEG was recorded for each infant at risk for seizures. Based on specific criteria, the background was graded as normal; immature for age; or mildly, moderately, or severely abnormal. The EEG was then monitored continuously until no electrographic seizures were recorded for 18-24 h.

RESULTS

Findings in the retrospective group of 29 infants and the prospective group of 22 infants did not differ. For the combined 51 infants, a normal or immature initial EEG background predicted the absence of seizures in the subsequent 18-24 h with a sensitivity of 96% [confidence interval (CI) 0.88, 1.0] and specificity of 81% (CI 0.67, 0.96). Administration of antiepileptic drugs (AEDs) before the start of the EEG recording did not affect this association.

CONCLUSIONS

In 51 consecutively monitored infants at risk for neonatal seizures, a normal or immature EEG background strongly predicted the absence of electrographic seizures in the subsequent 18-24 h; background abnormalities strongly predicted the occurrence of electrographic seizures concomitantly or in the subsequent 18-24 h of recording. Screening infants at risk for neonatal seizures with a routine EEG allows identification of infants at highest risk for seizures, thus conserving resources required for continuous EEG monitoring and facilitating early intervention for seizures.

Analgesia for neonatal circumcision: a randomized controlled trial of EMLA cream versus dorsal penile nerve block

OBJECTIVE

To compare the efficacy of the dorsal penile nerve block (DPNB) with a less invasive form of local anesthesia, eutectic mixture of local anesthetic (EMLA) cream, for reduction of pain during neonatal circumcision.

DESIGN

Prospective, blinded, randomized, controlled trial.

SETTING

Tertiary referral, neonatal intensive care nursery in a university teaching hospital.

PATIENTS

Fifty infants >/=341/2 weeks postmenstrual age and stable for discharge at time of circumcision; gestational age at birth 25 to 41 weeks; birth weight 600 to 4390 g; age at study 3 to 105 days. An additional cohort of term newborns (n = 20), who were not randomized, were circumcised without anesthesia.

INTERVENTIONS

Administration of either EMLA cream (0.5 g topically 1 hour before circumcision) or 1% lidocaine (0.7-1.0 mL subcutaneously 3 minutes before circumcision).

OUTCOME MEASURES

Primary: Neonatal Infant Pain Scale (NIPS) score; secondary: heart rate, respiratory rate. All outcome measures were assessed by an individual who was blinded to the group assignment and did not perform the circumcision.

RESULTS

NIPS scores were significantly lower in the DPNB infants (2.3 +/- 1.8) compared with the EMLA infants (4.8 +/- 0.7). NIPS scores in patients circumcised without anesthesia indicated severe pain. There was a significantly greater increase in heart rate over the duration of the circumcision in the EMLA group than in the DPNB group (49 vs 9 beats per minute). Adverse effects included small hematomas at the site of injection in DPNB infants (10/23), mild erythema at 1 and/or 24 hours after circumcision in the EMLA infants (3/21), and penile edema noted 5 days after circumcision requiring removal of the circumcision bell in 1 DPNB infant.

CONCLUSIONS

DPNB provides better pain reduction during neonatal circumcision than EMLA cream. EMLA cream may provide pain reduction compared with no anesthesia during neonatal circumcision.

Casein peptide release and passage to the blood in humans during digestion of milk or yogurt

In adult humans, after milk or yogurt ingestion, many peptides derived from alpha s1-, beta- or kappa-caseins were detected in stomach, including the kappa-caseinoglycopeptide, an inhibitor of platelet aggregation. Smaller peptides derived from casein and lactoferrin were recovered from duodenum. Two long peptides, the kappa-caseinoglycopeptide and the N-terminal peptide of alpha s1-casein, were absorbed and detected in plasma. These results support the concept that food-born peptides could have physiological activities in man.

Measurement of platelet aggregation peptide inhibitors by ultrasonic interferometry

Several peptide inhibitors of thrombin- or collagen-induced platelet aggregation and of the interaction between glycoprotein Ib and von Willebrand factor were studied by a new method--ultrasonic interferometry (Echo Cell). Inhibition of aggregate formation in a concentration-dependent manner was observed. The sensitivity of the method was 3 to 40 times higher than that of classical turbidimetry.

Dextromethorphan ameliorates effects of neonatal hypoxia on brain morphology and seizure threshold in rats

Hypoxic injury to the brain is mediated in part by NMDA receptors. Therefore, NMDA receptor blockade with dextromethorphan (DM), a non-competitive channel blocker, was hypothesized to ameliorate injury even when given after the hypoxic insult. Rats were exposed to 8% oxygen for 3 h on postnatal day 7. Within 20 min of exposure, animals received 30 mg/kg i.p. DM or normal saline. Littermates maintained in room air for 3 h also received DM or saline. At 14 days of age, 7 days after exposure, cortical thickness and hippocampal area were measured. At 70-90 days of age, approximately two months after exposure, in a separate group of rats, seizure threshold using pentylenetetrazol (PTZ) and passive avoidance learning and retention were determined. There were no gross changes in cellular morphology and no evidence for cellular necrosis in any of the exposure groups. However, cortical thickness was decreased in animals exposed to hypoxia. DM administration prevented this decrease. Hippocampal area was unaffected. Seizure susceptibility in adulthood was increased in animals exposed to hypoxia in the neonatal period. DM prevented the decrease in seizure threshold. There was no difference in passive avoidance learning or retention as a function of neonatal exposure condition. Mild to moderate hypoxia, previously thought not to produce any histologic changes, causes significant short-term loss of cortical thickness and long-term decrease in seizure threshold. DM appears to ameliorate these effects even when given after the hypoxic insult. These results implicate the glutamate receptor system in the pathophysiology of hypoxia damage and suggest that treatment with a glutamate receptor blocker when neonatal asphyxia is suspected would help ameliorate the consequences of such an insult.

Screening head ultrasound to detect intraventricular hemorrhage in premature infants

OBJECTIVE

The objective of this case-control study was to develop a screening protocol using head ultrasound (HUS) to detect high-grade intraventricular hemorrhage (IVH) in very-low-birthweight infants with greater specificity than current practice, while maintaining a high degree of sensitivity.

MATERIALS AND METHODS

All infants </= 32 weeks or </= 1500 g admitted to the neonatal intensive care unit between January 1, 1991 and December 31, 1992 were studied. The 1991 cohort was analyzed to identify the factors most sensitive and specific for predicting the occurrence of a high-grade (III or IV) IVH.

RESULTS

Eighty-five percent of infants born at 28-32 weeks gestation screened by 2 weeks of age for IVH had normal HUS scans. The factors most predictive of a high-grade IVH were gestational age < 28 weeks, forceps delivery, or any of the following in the first 2 weeks of life: seizures, head circumference increasing by more than 1 cm per week, base deficit >/= 10, or cardiopulmonary resuscitation in the neonatal intensive care unit.

CONCLUSION

Infants born at 28-32 weeks with a high-grade IVH can be identified with a high degree of sensitivity using refined screening criteria, eliminating 50 % of the HUS scans currently obtained for IVH screening.

Neonatal caffeine alters passive avoidance retention in rats in an age- and gender-related manner

Chronic administration of an adenosine receptor antagonist disturbs spatial learning and memory in adult mice and neonatal caffeine exposure results in long-term behavioral and biochemical sequelae in mice and rats. We thus postulated that early treatment with caffeine would have latent effects on learning and memory as measured in a passive avoidance paradigm. Rats were not handled or received caffeine (15-20 mg/kg/day) by gavage over postnatal days 2-6. At 28 or 70-90 days of age, rats were trained to avoid an electrified grid and tested for retention 24 h, 72 h, and 7 days later. At 28 days, caffeine-exposed rats required more trials to meet criterion than did control rats, regardless of gender. There was minimal effect on retention of either neonatal treatment or gender at this age. At 70-90 days, there was no effect of either gender or treatment on learning; however, there was a significant effect of gender (P < 0.05) on retention at 24 h that was more pronounced in neonatally caffeine-treated rats (P < 0.01). At 72 h, the effect of caffeine on retention differed between male and female rats. Neonatal caffeine exposure significantly improved retention in females (P < 0.01) and significantly decreased retention in males (P < 0.05). Thus, caffeine exposure limited to the first week of life resulted in alterations in passive avoidance retention that became apparent over pubertal development. These changes were a function of the gender of the animal.

Measurement of human platelet microaggregates by a new method: ultrasonic interferometry

We have adapted the ultrasonic interferometry technique (Echo-Cell), which was initially designed to study red blood cell aggregation and agglutination, to the detection of human platelet microaggregates. The experimental parameter chosen was the slope of the signal over the first 5 minutes of sedimentation. We compared our new method with the conventional aggregometry for the measurement of aggregates after thrombin-, collagen-, and epinephrine-induced platelet activation. Under these conditions we demonstrated the particular sensibility of the present method in detecting small platelet aggregates induced in the first phase of aggregation and formed by low concentrations of agonists. Furthermore, as an illustration of this method, we showed an inhibition of the formation of thrombin-induced platelet aggregates in a concentration-dependent manner by the well known antagonist arginine-glycine-aspartic acid-serine with a median inhibitory concentration of 0.4 micromol/L, which is 30 times lower than the median inhibitory concentration found by aggregometry.

Neonatal caffeine exposure alters seizure susceptibility in rats in an age-related manner

Early developmental exposure to caffeine in rats results in decreased susceptibility to certain chemically-induced seizures in the adult. To determine whether this effect first appears in adulthood or is present during preceding developmental stages, we exposed neonatal rats to caffeine and determined seizure thresholds in animals 28, 42 and 70-90 days of age. Rats were unhandled or received either vehicle (water) or caffeine (15-20 mg/kg/day) by gavage (0.05 ml/10 g) over postnatal days 2-6. At 28, 42, or 70-90 days of age, rats were infused intravenously with picrotoxin (PIC), bicuculline (BIC), pentylenetetrazol (PTZ), caffeine (CAFF), strychnine (STR), or kainic acid (KA). Seizure thresholds for each compound were analyzed as a function of neonatal treatment, sex, and age. At 28 days, neonatally caffeine-exposed rats had a higher seizure threshold only for PTZ (P < 0.03). At 42 days, neonatally caffeine-exposed rats had higher seizure thresholds for PIC (P < 0.0007) and PTZ (P < 0.0001) than did controls. These results at 28 and 42 days are compared with previously reported data that demonstrated that in adulthood, rats neonatally exposed to caffeine have higher thresholds for seizure induction with CAFF, PTZ, and KA. Thus, early developmental exposure to caffeine results in decreases in seizure susceptibility that are agent specific and may result in a delay in the decrease in seizure threshold that occurs for many agents between late juvenile ages and adulthood.

Neonatal caffeine exposure and seizure susceptibility in adult rats

Early developmental exposure to caffeine in rats results in changes in brain excitability that persist to adulthood. The mechanism of these alterations is unknown. To identify potential neurotransmitter systems involved, we exposed neonatal rats to caffeine and determined seizure thresholds for chemoconvulsants active at different CNS receptors in the adult animal. Rats were unhandled (NH) or received by gavage (0.05 ml/10 g) either vehicle (water) or caffeine (15-20 mg/kg/day) for postnatal days 2-6. At age 70-90 days, each rat was infused intravenously (i.v.) with picrotoxin (PIC), bicuculline (BIC) [convulsants acting at the gamma-aminobutyric acid/benzodiazepine (GABA/BDZ) receptor], pentylenetetrazol [PTZ, possibly acting at both GABA/BDZ and N-methyl-D-aspartate (NMDA) receptors], caffeine (acting at adenosine receptors), strychnine (STR, acting at glycine receptors), or kainic acid (KA, acting at the NMDA receptor). Seizure thresholds were analyzed as a function of neonatal treatment and sex. Thresholds for caffeine, PTZ, PIC, and KA were increased as a function of neonatal caffeine exposure (p = 0.01, 0.02, 0.02, and 0.005, respectively). The thresholds for BIC and STR were not altered. There were also gender differences in seizure susceptibility. Thresholds for seizures produced by BIC, caffeine, PIC, and STR were higher in females (p = 0.005, 0.005, 0.001, and 0.0001, respectively), but were not different for seizures caused by PTZ. These results suggest that early developmental exposure to caffeine affects later seizure susceptibility. Moreover, some of these effects are gender specific.

Use of glucagon to treat neonatal low-output congestive heart failure after maternal labetalol therapy

Labetalol is used to treat hypertensive crisis in women with preeclampsia. Glucagon was used as a nonselective beta-adrenergic agonist to treat a preterm infant with symptomatic beta-blockade caused by maternal labetalol therapy.

Effects of neonatal exposure to caffeine on adenosine A1 receptor ontogeny using autoradiography

The ontogeny of adenosine A1 receptor density was assessed via autoradiographical analysis of [3H]cyclohexyladenosine ([3H]CHA) binding in brains of 14-31-day-old rats as a function of exposure to caffeine over postnatal days 2-6. This exposure period was analogous to the period during which human infants are administered caffeine as treatment for apnea of prematurity. [3H]CHA binding was greatest in CA1 and CA3 hippocampus in both caffeine-exposed and control rats across all ages. Within the anterior, ventral, lateral and medial regions of the thalamus of unmanipulated rats, [3H]CHA binding did not change with age. In caffeine-exposed rats, however, [3H]CHA binding increased significantly within these thalamic subregions as the rats aged. In addition, with age in both treatment groups, the molecular and granular layers of the cerebellum and the CA1 and dentate gyrus of the hippocampus displayed increasing [3H]CHA density. Furthermore, regardless of age, [3H]CHA binding was decreased in the molecular layer of neonatally caffeine-exposed animals as compared to controls. Thus, limited exposure to caffeine within the first postnatal week altered the subsequent expression of adenosine A1 receptors in most subregions of the thalamus and in the molecular layer of the cerebellum.

[Measurement of immunologic agglutination of erythrocytes by ultrasonic interferometry]

Ultrasound interferometry is a new methodology which has been developed in our laboratories in order to measure precisely and quickly the size of particles sedimenting in liquid on horizontal surface, upon gravity. Applied to red blood cells, this method evaluates the sedimentation of erythrocytes, their aggregation induced by proteins or aggregating compounds as well as their agglutination upon immune reactions. The quantitative assessment of red cell agglutination was applied to the study of blood groups and to the search for red cell antibodies. Preliminary results show that ultrasound interferometry is 1) quantitative, measuring the size of agglutinates; 2) sensitive; 3) specific; 4) fast; 5) able to detect irregular antibodies.

Neonatal caffeine exposure alters developmental sensitivity to adenosine receptor ligands

Studies were done to determine whether the apparent changes in behavioral sensitivity to adenosine receptor ligands that occur with age and with neonatal caffeine exposure were due to a change in sensitivity of the receptor for the ligand or to a more fundamental change in the receptor. Using an animal model that mimics the brain developmental period and level of caffeine exposure in human premature neonates treated with caffeine for apnea of prematurity, behavioral and neurochemical investigations were undertaken. The locomotor responses to acute challenge with caffeine (15, 30 and 60 mg/kg) and with D-phenylisopropyladenosine (D-PIA) (0.038 and 0.38 mg/kg), an adenosine receptor agonist, were measured in control and neonatally caffeine-exposed rats at 12, 15, 18, and 28 days of age. The dissociation constants (Kd) and maximal binding densities (Bmax) for agonist binding at the adenosine A1 receptor site were determined over a similar time period. Caffeine displacement of an adenosine A1 agonist was also measured to examine in vitro sensitivity to caffeine as a function of age and neonatal caffeine exposure. Our studies demonstrated that the differential responses to adenosine receptor ligands seen as a function of both age and neonatal caffeine exposure could not be overcome by merely increasing the doses of ligand administered. In addition, the results of the binding studies indicated that changes in the adenosine receptor are occurring as a function of age in different regions of the brain of control animals and that this development is influenced by neonatal caffeine exposure.

Ultrasonic interferometry: study of particle sedimentation in liquid

An ultrasonic interferometry method was designed to study sedimentation of particles in liquid. The method, based on A mode echography, measures the amplitude of ultrasonic waves reflected (echo E1) by a fixed interface I1 called "solid plate-sediment" interface formed when particles are sedimenting on a solid plate. The amplitude of the echo depends both on mechanical properties of the three media (solid plate, sediment and suspension) on the thickness of the sediment and on the presence of a second mobile interface I2 called "sediment-suspension" interface. In the first phase of sedimentation when the second interface is very close to the first, two reflected waves interfere. Then, in the second phase of sedimentation when the sediment is thick enough, the amplitude of the echo E1 depends only on the sediment and solid plate properties. The first phase will give information on the sedimentation rate of particles (SR). We have compared SR of particles determined by this method with SR measured in a cylindrical tube of the same geometry as the ultrasonic measurement cell and with theoretical values of the sedimentation rate given by theoretical models.

Neonatal exposure to therapeutic caffeine alters the ontogeny of adenosine A1 receptors in brain of rats

Caffeine is a methylxanthine, commonly used in the premature neonate to treat apnea of prematurity. It is efficacious and appears to have few short-term side effects. An animal model, designed to mimic the developmental period in brain and level and duration of exposure in humans, was used to investigate possible long-term effects of early developmental exposure to caffeine on the ontogeny of the adenosine receptor to which caffeine binds. Specific binding at the adenosine A1 receptor, in five distinct regions of the brain was determined in rats, 14-90 days old, as a function of early postnatal exposure to caffeine, over days 2-6. In cortex, cerebellum and hippocampus but not in the brain stem or hypothalamus, there was an increase in specific binding, following neonatal exposure to caffeine, compared to specific binding in control animals. Kinetic analysis of binding to the A1 site in cortical tissue suggests that this increase was due to an increased maximum binding density (Bmax); binding affinity (Kd) did not change. Thus, limited exposure to caffeine, in the early neonatal period, may result in up-regulation of the adenosine A1 receptor that persists to young adulthood in the rat.

Assessment of red blood cell aggregation with dextran by ultrasonic interferometry

Aggregation of human red blood cells (RBCs) induced by dextrans of various molecular weight has been studied by using a new ultrasonic interferometry method. This method, based on A-mode echography, allowed for the measurement of the accumulation rate of particles on a solid plate which is related to their sedimentation rate (i.e., to their mean size). The initial aggregation process, the mean and the maximum sedimentation rate of aggregates and the packing of the sedimented RBCs have been investigated. Effects of hematocrit, molecular weight of dextrans and inhibition by dextran 40 on the RBC aggregation induced by dextran of higher molecular weight have been determined by analysing variations of the aggregate size. Results obtained confirm the aggregation effect of dextrans of molecular weights equal or higher than 70,000 dalton and disaggregation effect of dextran 40,000 dalton on aggregation by dextrans of higher molecular weight.

Aging-related changes in brain metabolism are altered by early developmental exposure to diazepam

To study the long-term effects of prenatal diazepam (DZ) exposure, 31P NMR (nuclear magnetic resonance) spectra and levels of thiobarbituric acid (TBA)-reactive material were measured in the brains of rats from 3 to 26 months of age. In control rats, there were aging-related increases in levels of TBA-reactive material, decreases in intracellular pH (pHi) and alterations in phosphocreatine (PCr) utilization. Prenatal (late gestational) DZ exposure induced lasting, dose-related and age-related alterations in levels of TBA-reactive material and pHi. The results indicate that the prenatal chemical environment can influence cellular metabolism throughout the lifetime of the organism, and that the process of aging can in turn interact with the consequences of prenatal drug exposure.

Early developmental exposure to benzodiazepine ligands alters brain 31P-NMR spectra in young adult rats

Alterations in brain high energy phosphate compounds, using 31P-NMR (nuclear magnetic resonance) spectroscopy, were measured in vivo in young adult (3-4 months) rats following prenatal exposure to ligands acting specifically at benzodiazepine (BDZ) binding sites. The exposure induced a decrease in intracellular pH that indicated a predominant interaction of the drugs in utero with central-type BDZ receptor sites. Late gestational exposure to BDZ ligands also induced changes in brain phosphocreatine (PCr) utilization. Exposure to the lowest dose of DZ (1.0 mg/kg) but not the higher dose (2.5 mg/kg) induced a significant change in PCr utilization. Exposure to the central-type BDZ receptor antagonist RO15-1788 alone clearly altered PCr utilization in adult offspring, and DZ (2.5 mg/kg) when administered concurrently was not able to prevent this effect. Though exposure to a peripheral-type ligand (PK11195) had no effect by itself, it converted the effect of the high dose of DZ to that of the low dose. Together, these results indicate an interaction during development between the central and peripheral-type BDZ binding sites on organization and/or regulation of cellular energy metabolism. Normalized ATP levels were not changed by any prenatal treatment indicating adequate buffering of intracellular ATP by phosphocreatine. The dopaminergic antagonist haloperidol did not alter intracellular pH or any index of phosphate metabolism indicating a selective receptor mediated role for BDZ ligands in influences on the long term organization of intracellular phosphate metabolism.

Neonatal caffeine exposure alters adenosine receptor control of locomotor activity in the developing rat

An animal model was developed to approximate the magnitude and brain developmental period of caffeine exposure experienced by the human infant receiving caffeine for apnea of prematurity. Serum levels of caffeine of 5-15 mg/l over the 24-hour period were achieved by administering to rat pups a loading dose of 20 mg/kg p.o. on day 2, followed by 15 mg/kg p.o. on days 3-6 of life. Locomotor activity, both spontaneous and following an acute challenge with D-phenylisopropyl adenosine (an adenosine receptor agonist, 10 mumol/kg i.p.) or caffeine (an adenosine receptor antagonist, 100 mumol/kg i.p.), was measured in 12-to 28-day-old native rat pups or pups neonatally exposed to caffeine. The stimulatory effect of acute caffeine on locomotor activity was developmentally delayed in neonatally exposed pups. It is postulated that early exposure to caffeine in some way altered the development of the central adenosine receptor control over locomotor activity.

Determination of erythrocyte transit times through micropores. II-- Influence of experimental and physicochemical factors

A new red blood cell filtration system, termed the Cell Transit Time Analyzer (CTTA), has been developed in order to measure the individual transit times of a large number of cells through cylindrical micropores in special "oligopore" filters: the system operates on the electrical conductometric principle and employs special computer software to provide several measures of the resulting transit time histogram. Using this system with filters having pore diameters of 4.5 or 5.0 cm and length to diameter ratios of 3.0 to 4.7, we have evaluated the effects of several experimental factors on the flow behavior of normal and modified human RBC. Our results indicate : 1) linear PBC pressure - flow behavior over a driving pressure range of 2 to 10.5 cm H2O with zero velocity intercepts at delta P = 0, thus suggesting the Poiseuille - like nature of the flow; 2) resistance to flow or "apparent viscosities" for normal RBC which are between 3.1 to 3.9 cPoise and are independent of driving pressure and pore geometry; 3) increased flow resistance (i.e., increased transit times) for old versus young RBC and for RBC made less deformable by DNP-induced crenation or by heat treatment at 48 degrees C; 4) increased mean transit time and poorer reproducibility when using EDTA rather than heparin as the anticoagulant agent. Further, using mixtures of heat-treated and normal RBC and various percentile values of the transit time histogram. We have been able to demonstrate the presence of sub-populations of rigid cells and thus the value of measurements which allow statistical analyses of RBC populations.

Determination of erythrocyte transit times through micropores. I--Basic operational principles

To study the transit times of each red blood cell passing through cylindrical micropores and in order to evaluate sub-population of cells with regard to their deformability, we have developed a new system called the cell transit time analyser (CTTA). By using an AC voltage (100 KHz) across a special filter, we measure the electrical conductance change produced by the cells passing through the pores under a known driving pressure. This computer based device provides the distribution of transit times tau for 2000 cells in 1 minute and as a result the mean transit time [tau]. Experiments with red cells were designed to evaluate the flow behavior of both normal cells and cells whose mechanical properties were artificially altered. Cell volume was changed by use of non-isotonic media. Cell shape and cell volume were modified by varying the pH of the suspending buffer. Results of these experiments are: 1) a skew distribution of transit times towards high tau values for both control cells and artificially altered cells is observed: 2) [tau] is minimum for isotonic conditions and increases sharply for either hypotonic or hypertonic media: 3) [tau] is minimum at physiological pH and increases for either acid or alcaline changes of pH.

In vivo 31P nuclear magnetic resonance measurement of chronic changes in cerebral metabolites following neonatal intraventricular hemorrhage

The purpose of this study was to determine whether cerebral metabolic changes occur after intraventricular hemorrhage in the newborn. Five babies with bilateral grade 3 to 4 intraventricular hemorrhage were compared with 15 preterm infants without intraventricular hemorrhage. Cerebral high-energy phosphorus metabolites and intracellular pH were measured with in vivo 31P nuclear magnetic resonance spectroscopy. Spectra were collected initially within the first 2 weeks of life, and then every other week until discharged from the hospital. The phosphocreatine to inorganic phosphate ratio and the phosphocreatine to adenosine triphosphate ratio were significantly lower in the group with intraventricular hemorrhage, but differences in intracellular pH were not significant. Differences between babies with and without intraventricular hemorrhage varied with postconceptional age: in those with intraventricular hemorrhage, the phosphocreatine to adenosine triphosphate ratio was decreased at all postconceptional ages, and the phosphocreatine to inorganic phosphate ratio was lower in babies with intraventricular hemorrhage and younger than 30 weeks. Results of this study confirm the presence of chronic metabolic changes following intraventricular hemorrhage which may exacerbate neurologic damage after intraventricular hemorrhage in the newborn.

Anesthetic-induced corneal lesions in developmentally sensitive rats

Developmental critical periods for the induction of abnormalities by exposure to exogenous substances need not be confined to the early embryonic stage of organogenesis. The combination of ketamine hydrochloride and xylazine, two commonly used anesthetic agents, resulted in a corneal epithelial calcium deposition in 84% of rat pups whose exposure was limited to a single injection during the third postnatal week only. Concurrent exposure to ketamine hydrochloride, xylazine, and yohimbine, an alpha 2 adrenergic receptor antagonist, resulted in corneal lesions in only 6% of rat pups so exposed. The etiology is presently not understood but may involve interference with neurally directed corneal development. Corneal desiccation may also play a role. Altered drug metabolism, and toxic interactions resulting from a changing oxygen or light milieu are less likely etiologic mechanisms. Aspects of corneal development and mechanisms by which drugs can interact with and disturb normal maturational sequences can now be approached.

Aggregation of red blood cells studied by ultrasound backscattering

The erythrocyte aggregation phenomenon is an important factor in capillary circulation. This phenomenon can be evaluated by a number of methods (microscopic observations, viscometry, light measurements) which cannot be applied simply to in vivo measurements. In contrast, ultrasound which propagates through soft tissues allows measurement of the mechanical properties of red blood cell (RBC) suspensions which depend on the aggregation phenomenon. We devised an apparatus in order to measure in vitro the ultrasonic backscattering intensity of RBC suspensions. First, with latex particles of different sizes, the ultrasonic backscattering coefficient has been measured in order to evaluate the apparatus response. Then, the ultrasonic backscattering coefficient of different aggregated erythrocyte suspensions has been measured and correlated with the erythrocyte sedimentation rate. Finally, the size of RBC aggregates of different suspensions has been evaluated.

Brain oxidative phosphorylation following alteration in head position in preterm and term neonates

An alteration in head position, which effects cerebral blood flow, may increase the risk for intraventricular hemorrhage in the critically ill infant. The purpose of this study was to evaluate in vivo cerebral oxidative metabolism as an index of tissue oxygen delivery reflecting brain blood flow, in healthy preterm and term infants following a change in head position. Cerebral phosphoenergetics using 31 phosphorus nuclear magnetic resonance spectroscopy were measured in 10 preterm and eight term infants following three different head positions: neutral, prone, and supine. All infants were clinically stable at the time of study. The phosphocreatine to inorganic phosphate ratio, an indicator of bioenergetic reserve, was determined. The mean +/- SD for phosphocreatine to inorganic phosphate ratio in the neutral position in preterm and term infants was 1.08 +/- 0.15 and 1.12 +/- 0.21, respectively, and did not change significantly following head turning. These data suggest that any alteration in cerebral blood flow as a result of a change in head position in the healthy neonate may be compensated by physiological and biochemical regulations so that no changes in brain oxidative phosphorylation are measurable.

[Uterine and sigmoid perforations following voluntary interruption of pregnancy by aspiration. A case report (author's transl)]

A recent case of mixed uterine and colic perforations associated with generalized peritonitis is reported, the lesions developing within the context of the digestive complications of the method known as aspiration for voluntary interruption of pregnancy. The frequency, severity, and treatment of these lesions are described, urgent laparotomy being necessary to correct both abdominal digestive tract and genital lesions. Prevention of these complication technique. Coelioscopy is essential if a perforation is suspected, and must be followed by a laparotomy if its presence is confirmed.

[Acute cholecystitis without gallstones following gastrectomy. A report on two cases (author's transl)]

Two recent cases of acute cholecystitis without gallstones following gastrectomy are reported. Details of the cases are described and the rare nature of this postoperative complication emphasized. Clinical diagnosis is difficult and the cause of this complication is usually not ascertained. Cholecystectomy remain the basic treatment, of choice, but cholecystotomy or simple drainage may be the only possible therapy, and should be employed whenever necessary. Postoperative acute cholecystitis is rarely observed, is usually associated with gallstones, and occurs in patients with previously healthy gallbladders in only exceptional cases, usually following digestive tract operations (Thomoret and Bronstein, 9). The initial surgical intervention then involves the stomach, whether it be a gastrectomy or vagotomy (Champeau, Delattre, 2). Two recent cases of post-gastrectomy acute cholecystitis without gallstones led to a review of the published literature to determine the frequency of this complication, and an attempt to define its characteristics.

[Traumatic recto-vesical wounds (author's transl)]

The authors report a case of a traumatic recto-vesical wound: such cases are rare and serious. The importance of an early diagnosis, which is not usually difficult, allows quick reparative treatment by the trans vesical route associated with a colostomy higher up which is later closed.