Steroids for intubated croup masking airway haemangioma

Recently, the beneficial role of steroids for acute laryngotracheobronchitis has been more clearly defined for both intubated and unintubated patients. However, corticosteroids also improve the clinical signs of airway haemangiomata. Two patients are described who illustrate how this can be a source of diagnostic confusion.     

Population genetics of phenylketonuria

Phenylketonuria (PKU) is an autosomal recessive disorder caused by a large number of mutations at the phenylalanine hydroxylase (PAH) locus, most of which are strongly associated with specific RFLP or VNTR haplotypes. One of the major questions remaining in PKU research is why this apparently maladaptive disorder has been maintained at a frequency of approximately 1 in 10000 among Caucasians. A growing number of studies have provided evidence that both the relatively high frequency of PKU and the strong mutation/haplotype associations might reflect the existence of multiple founding populations for PKU. Examples of putative founding populations for PKU in both Europe and Asia will be presented. Some PAH mutations are associated with multiple haplotypes, suggesting recurrence. Evidence for and against recurrence as the mechanism responsible for the association of the R408W mutation with RFLP haplotypes 1 and 2 will be discussed.     

Molecular analysis of PKU in Ireland

Classical phenylketonuria (PKU: McKusick No. 261600) is caused by mutations occurring at the phenylalanine hydroxylase (PAH) locus on chromosome 12 and has a prevalence in Ireland of 1 in 4500. We examined 304 independent alleles from 350 patients for the presence of six mutations and have characterized VNTR alleles within the minisatellite region 3' to the PAH gene in patients carrying the most prevalent mutation. R408W was the most common mutation found, with a relative frequency of 42%. All other mutations had relative frequencies of <10%. VNTR analysis showed that the R408W mutation is associated with the VNTR-8 allele in the Irish population, indicating that R408W is associated with RFLP haplotype 1. This differs from that reported from eastern Europe where R408W is associated with RFLP haplotype 2/VNTR-3; an observation which has led several groups to propose a Balto-Slavic origin for this mutation. These results support the hypothesis of a second, independent founding event for the R408W mutation on an RFLP haplotype 1 VNTR-8 chromsome background in the Irish/Celtic population.     

Prevalence of behaviour disorders in low birthweight infants

OBJECTIVE--To determine the prevalence of behaviour disorders in low birthweight infants. DESIGN--Children of birth weight < or = 2000 g born to mothers resident in Merseyside in 1980-1 assessed using the Rutter parent and teacher behaviour questionnaires and the Conner modification of the Rutter teacher questionnaire. Children attending normal schools were assessed with controls matched for age, sex, and class in school. Children attending special schools were assessed unmatched. SUBJECTS--233 matched case-control pairs attending normal primary schools and 46 unmatched children attending special schools. SETTING--Primary and special schools. MAIN OUTCOME MEASURES--Emotional, conduct, and undifferentiated behaviour disorders and hyperactivity. RESULTS--On the parental questionnaire screen, 36% of the cases and 22% of the controls had a behaviour disorder and on the teacher questionnaire the proportions were 27% and 12% respectively. Hyperactivity was significantly more common among male cases than their controls (21% v 5.0%) but differed little among female cases and controls (9% v 7%). CONCLUSIONS--Improving neonatal survival of low birthweight infants is accompanied by a higher prevalence of behaviour disorders. The long term implications for psychiatric morbidity and other adult disease must be monitored.     

Rapid prenatal diagnosis of trisomies 13, 18, 21 and sex chromosome anomalies by fluorescence in situ hybridization: a year's experience

The present paper summarizes our first 12 months' experiences of rapid prenatal diagnosis using commercially available diagnostic fluorescence in situ hybridization (FISH) probes for chromosomes X, Y, 13, 18 and 21. The data clearly demonstrate that the advantage of using FISH as an adjunct technique is the fast and reliable determination of the common fetal chromosomal aneuploidies; the results are available in less than 24 hours instead of the 7-14 days with standard techniques.     

Assessment of cardiac output in children: a comparison between the pressure recording analytical method and Doppler echocardiography.

OBJECTIVE: To assess cardiac output in pediatric patients with the pressure recording analytical method (PRAM) and the Doppler echocardiography method. PRAM derives cardiac output from beat-by-beat analysis of the arterial pressure profile (systolic and diastolic phase) in the time domain. DESIGN: A prospective observational study. SETTING: Pediatric intensive care unit at a tertiary care children's hospital. PATIENTS: Forty-eight patients between the ages of 1 month and 18 yrs. INTERVENTIONS: Femoral or radial artery catheterization and mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: Cardiac output was simultaneously estimated by Doppler echocardiography and PRAM. Cardiac output values obtained by Doppler echocardiography (2.7 +/- 1.6 L/min, range 0.92-8.20) were significantly correlated with those estimated by PRAM (2.6 +/- 1.7 L/min, range 0.89-7.48; r2 = .99, p < .01). The mean difference between the two estimates was 0.12 +/- 0.27 L x min(-1) (95% confidence interval, -0.54 to 0.77 L x min(-1)). CONCLUSIONS: In the range of ages evaluated, PRAM provides reliable estimates of cardiac output when compared with noninvasive techniques.     

Physiologic role of nitric oxide in the maintenance of uterine quiescence in nonpregnant and pregnant sheep

OBJECTIVE: This study evaluated the role of nitric oxide in the maintenance of uterine quiescence in nonpregnant and pregnant ewes. STUDY DESIGN: Sixteen ovariectomized nonpregnant and 10 pregnant (115 days' gestation) chronically instrumented ewes were studied. Uterine contractility was assessed by electromyography and intrauterine pressure recordings. Nitric oxide synthase inhibition was induced with nitro-L -arginine methyl ester or aminoguanidine (4. 5 mg/kg per hour) given during estrogen replacement with 17beta-estradiol (100 microg/d) or in late gestation. In the pregnant group we evaluated the ability of nitric oxide synthase inhibition to alter the responsiveness to oxytocin-induced uterine contractility. Blood pressure and common internal iliac artery blood flow were assessed to confirm nitric oxide synthase inhibition. In addition, the effects of the nitric oxide donor nitroglycerin and the cyclooxygenase inhibitor indomethacin were studied in nonpregnant sheep. The effect of nitric oxide in vitro on myometrial spontaneous and induced contractions was also studied. RESULTS: In nonpregnant estrogen-replaced sheep, nitric oxide synthase inhibition and nitroglycerin administration did not alter uterine contractility, despite significant changes in blood pressure. In contrast, indomethacin decreased electromyographic results to 70% of baseline after 1 hour and 47% after 2 hours. In pregnant ewes nitric oxide synthase inhibition failed to alter uterine contractility in response to oxytocin. These findings are in contrast to results of the in vitro study in which nitric oxide was shown to relax sheep myometrium. CONCLUSION: The absence of significant effects of nitric oxide synthase inhibition and nitric oxide donors on uterine contractility in vivo suggests that nitric oxide does not play a physiologic role in the regulation of uterine contractility in nonpregnant or pregnant ewes.