Is mechanical ventilation associated with intraventricular hemorrhage in preterm infants?

Background

The impact of mechanical ventilation on the incidence of intraventricular hemorrhage (IVH) in very low birth weight (VLBW) infants is unknown, simply because the vast majority of these infants have been routinely intubated and mechanically ventilated. There is a growing interest in the use of early nasal continuous positive airway pressure (ENCPAP) and avoiding mechanical ventilation.

Objectives

To examine the role of mechanical ventilation since delivery room in determining severe IVH in VLBW infants in two neonatal units that follow the same strategy of respiratory management using ENCPAP.

Methods

We collected data on delivery room intubation and mechanical ventilation during the first 3 days of life in VLBW infants. Logistic regression model was constructed to test the relationship between early mechanical ventilation and the diagnosis of severe IVH after controlling for significant confounding variables, such as BW, gender, duration of mechanical ventilation, and partial pressure of CO₂ (PCO₂).

Results

Of the studied 340 VLBW, 35 infants had severe IVH; most of them received mechanical ventilation that started either in the delivery room (n = 12) or during the first (n = 10) and second (n = 3) days of life. Severe IVH was independently associated with lower BW, mechanical ventilation in the delivery room, and the cumulative duration of mechanical ventilation during the first 3 days. The adjusted odds ratio for severe IVH in infants intubated in delivery room was (OR = 2.7, CI: 1.1–6.6, P = 0.03). Severe IVH was not associated with gender, prenatal steroids, early sepsis, or patent ductus arteriosus.

Conclusions

Mechanical ventilation plays a role in predicting severe IVH. Both the time at which ventilation was initiated and the duration of ventilation are important determinants of severe IVH. Risk for severe IVH in infants who were never intubated in delivery room or during the first 3 days of life is miniscule.     

Measurement of the rate of myelination using a fluorescent analogue of ceramide

Fluorescence digital imaging microscopy was used to investigate the process of myelin formation by Schwann cells in neuronal cocultures. The uptake of the fluorescent ceramide analogue N-[5-(5,7-dimethyl BODIPY™)- 1-pentanoyl]D-erythro-sphingosine (C₅-DMB-ceramide) and its return to the plasma membrane as the corresponding fluorescent sphingomyelin and galactocerebroside analogues were measured. Through observation of this process it was possible to determine the rate of lipid synthesis in myelin internodes. The highest rate of synthesis of fluorescent sphingomyelin and galactocerebroside analogues was observed between days 3 and 7 after induction of myelination. This rate was approximately 5-fold greater than the steady-state rate of synthesis in fully myelinated internodes and 10-fold higher than the rate observed prior to myelination. The internode diameter increased during the first 3 days of myelination, but this was followed by a reduction in diameter and then an increase until the myelin sheath formation was completed. Internodes were found to be heterogeneous in terms of lipid distribution, with fluorescence intensities ranging 5-fold in myelinating cultures. Additionally, the rate of lipid transport along the internode was slow since there was a quicker increase in fluorescence intensity near the cell body of the Schwann cell than near the nodes of Ranvier. The results show that fluorescence digital imaging microscopy can be used to study the process of myelin formation and to determine the rate of formation, lipid transport, and heterogeneity of the myelin membrane. J. Neurosci. Res. 49:497–507, 1997. © 1997 Wiley-Liss, Inc.     

Cadmium pathways during gestation and lactation in control versus metallothoinein 1,2-knockout mice.

Effects of metallothionein (MT) on cadmium absorption and transfer pathways during gestation and lactation in mice were investigated. Female 129/SvJ metallothionein-knockout (MT1,2KO) and metallothionein-normal (MTN) mice received drinking water containing trace amounts of (109)CdCl(2) (0.15 ng Cd/ml; 0.074 micro Ci (109)Cd/ml). (109)Cd and MT in maternal, fetal, and pup tissues were measured on gestation days 7, 14, and 17 and lactation day 11. In dams, MT influenced both the amount of (109)Cd transferred from intestine into body (two- to three-fold higher in MT1,2KO than MTN dams) and tissue-specific (109)Cd distribution (higher liver/kidney ratio in MT1,2KO dams). Placental (109)Cd concentrations in MT1,2KO dams were three- and seven-fold higher on gestation days 14 and 17, respectively, than in MTN dams. Fetal (109)Cd levels were low in both mouse types, but at least 10-fold lower in MTN fetuses. MT had no effect on the amount of (109)Cd transferred to pups via milk; furthermore, 85-90% of total pup (109)Cd was recovered in gastrointestinal tracts of both types, despite high duodenal MT only in MTN pups. A relatively large percentage of milk-derived intestinal (109)Cd was transferred to other pup tissues in both MT1,2KO and MTN pups (14 and 10%, respectively). These results demonstrate that specific sequestration of cadmium by both maternal and neonatal intestinal tract does not require MT. Although MT decreased oral cadmium transfer from intestine to body tissues at low cadmium exposure levels, MT did not play a major role in restricting transfer of cadmium from dam to fetus via placenta and to neonate via milk.     

Age differences in risky driving

The present paper examines age differences in reported riskydriving (e.g. drinking and driving, aggressive driving, non-useof seat-belts), other risky behavior (e.g. heavy use of alcohol,use of illicit drugs) and traffic accident and violation involvement.The results are based on a national survey of 10 000 respondentsaged 16–69 who were interviewed during a telephone survey.Young drivers (16–24) were not only more likely to engagein risky driving and have higher accident and violation rates(corrected for distance traveled) but they were also more likelyto report engaging in other risky behaviors. The 20–24age group was generally more likely than the 16–19 agegroup to report risky behavior, whether driving related or not,while the 16–19 age group tended to have higher accidentand violation rates. Similar age differences were observed forboth male and females, although the age effect was more pronouncedfor males. Risky driving, the other risky behaviors and accidentand violation involvement were all positively and significantlycorrelated but the magnitude of the correlation was modest.Potential programs for promoting safer driving among youth arediscussed.     

Failure of microchromatographic measurement of fetal hemoglobin in beta zero thalassemia-hereditary persistence of fetal hemoglobin.

We report microchromatographic measurement of fetal hemoglobin (HbF) proportions in a 36-year-old African-American multigravida woman. At 34 weeks she delivered a 630-g male infant who subsequently did well. Hemoglobin electrophoresis of the hemolysate revealed nearly 100% HbF without HbA, an extremely unusual naturally occurring sample. Family studies revealed a combination of hereditary persistence of fetal hemoglobin (HPFH) and beta zero-thalassemia minor. Southern blot technique confirmed heterozygous alpha 2 thalassemia and HPFH but failed to identify the beta thalassemic lesion. The absence of HbA and the very high amounts of HbF led us to measure HbF by several methods to confirm the accuracy of microchromatography of HbF at values approaching 100%. HPLC revealed a 14% F1 suggestive of microchromatographic underestimation due to glycated HbF. We conclude that cation-exchange microchromatography and the Betke method of alkali denaturation underestimate HbF values as they approach 100% and do not recommend these procedures in this rare situation.     

The Clinical Implications of Fatty Pancreas: A Concise Review

Fatty pancreas is a newly recognized condition which is poorly investigated until today as compared to nonalcoholic fatty liver disease. It is characterized by pancreatic fat accumulation and subsequent development of pancreatic and metabolic complications. Association of fatty pancreas have been described with type 2 diabetes mellitus, acute and chronic pancreatitis and even pancreatic carcinoma. In this review article, we provide an update on clinical implications, pathogenesis, diagnosis, treatment and outcomes.     

Association of Linear Growth Impairment in Pediatric Crohn's Disease and a Known Height Locus: A Pilot Study

The etiology of growth impairment in Crohn's disease (CD) has been inadequately explained by nutritional, hormonal, and/or disease‐related factors, suggesting that genetics may be an additional contributor. The aim of this cross‐sectional study was to investigate genetic variants associated with linear growth in pediatric‐onset CD. We genotyped 951 subjects (317 CD patient–parent trios) for 64 polymorphisms within 14 CD‐susceptibility and 23 stature‐associated loci. Patient height‐for‐age Z‐score < ?1.64 was used to dichotomize probands into growth‐impaired and nongrowth‐impaired groups. The transmission disequilibrium test (TDT) was used to study association to growth impairment. There was a significant association between growth impairment in CD (height‐for‐age Z‐score < ?1.64) and a stature‐related polymorphism in the dymeclin gene DYM (rs8099594) (OR = 3.2, CI [1.57–6.51], p = 0.0007). In addition, there was nominal over‐transmission of two CD‐susceptibility alleles, 10q21.1 intergenic region (rs10761659) and ATG16L1 (rs10210302), in growth‐impaired CD children (OR = 2.36, CI [1.26–4.41] p = 0.0056 and OR = 2.45, CI [1.22–4.95] p = 0.0094, respectively). Our data indicate that genetic influences due to stature‐associated and possibly CD risk alleles may predispose CD patients to alterations in linear growth. This is the first report of a link between a stature‐associated locus and growth impairment in CD.