Effect of spinal surgery on lung function in Duchenne muscular dystrophy.

BACKGROUND: The effect on subsequent respiratory function of spinal stabilisation for scoliosis in Duchenne muscular dystrophy is unclear. In order to clarify this clinical problem, changes in the forced vital capacity of a group of children with Duchenne muscular dystrophy who had undergone spinal surgery were measured and compared with a group of children with Duchenne muscular dystrophy who had not had surgery. METHODS: In this retrospective study 17 boys with Duchenne muscular dystrophy who underwent spinal stabilisation at a mean age of 14.9 years (surgical group) were compared with 21 boys with Duchenne muscular dystrophy who had not had surgery (non-surgical group). The mean (SD) Cobb angle of the surgical group at 14.9 years was 57 (16.4) degrees, and of the non-surgical group at 15 years was 45 (29.9) degrees. Forced vital capacity expressed as percentage predicted (% FVC) was measured in total over a seven year period in the surgical group and over 6.5 years in the non-surgical group, and regression equations were calculated. Survival curves for both groups were also constructed. RESULTS: No difference was found between spinal stabilisation (surgical group) and the non-surgical group in the rate of deterioration of % FVC which was 3-5% per year. There was no difference in survival in either group. CONCLUSIONS: Spinal stabilisation in Duchenne muscular dystrophy does not alter the decline in pulmonary function, nor does it improve survival.

Are perinatal autopsy rates satisfactory?

OBJECTIVE: To determine perinatal autopsy rates and whether any maternal or obstetric factors affect consent for autopsy. DESIGN: Ascertainment of perinatal autopsy rates between 1990 and 1993 for three categories of perinatal deaths: termination of pregnancy for antenatally diagnosed anomalies; fetal deaths and still-births; and neonatal and post-neonatal deaths. A case-control study matched deaths for which consent for autopsy was refused with the next death in the same category for which consent was given. SETTING: A tertiary maternity hospital in South Australia. RESULTS: The autopsy rate for pregnancies terminated for fetal abnormalities was 92.4% (171/185) and for intrauterine death was 87.7% (264/301); the rates in these two groups were higher for registrable births (gestation > 20 weeks) than non-registrable births. The overall autopsy rate in liveborn babies was 58.8% (80/136), the neonatal autopsy rate being 59.6% (68/114). No significant differences were found with regard to gestational age at birth, maternal gravidity and parity, employment, health insurance or marital status, or, among liveborn babies, postnatal age, between the autopsy and non-autopsy groups. CONCLUSIONS: Perinatal autopsy rates are higher than rates in adults but are lower in registrable births than the recommended 75%. Consent for autopsy is the limiting factor. There is a need for a clearer definition of perinatal autopsies, and perinatal autopsy rates, to take into account non-registrable deliveries.

Relationship of smoking and albuminuria in children with insulin-dependent diabetes.

Recent evidence suggests the rise in urinary albumin excretion preceding diabetic nephropathy may represent a continuum. We therefore studied factors relating to albumin excretion rate in children with insulin-dependent diabetes. Normal overnight albumin excretion rate was determined in 690 healthy schoolchildren. The 95th centile was 7.2 micrograms min-1. Patients included 169 children with IDDM aged 12.4 +/- 3.1 years who performed 4.8 +/- 0.4 overnight collections during 15 +/- 0.5 months and were analysed cross sectionally. They were stratified accordingly to mean albumin excretion rate: normal < 7.2 micrograms min-1, borderline 7.2-20 micrograms min-1, microalbuminuria 20-200 micrograms min-1; 96/169 patients performed 6.4 +/- 0.2 overnight collections during 24 months follow-up and were analysed longitudinally. Cigarette smoking was determined by history and urine cotinine levels. Smoking correlated with albumin excretion rate, independent of age and other variables, in cross-sectional and longitudinal analysis (p < 0.003). Smoking was more prevalent in the borderline albuminuria and microalbuminuria groups (p < 0.004, p < 0.001). Mean HbA1c during follow-up and mean HbA1c since diagnosis were significantly higher in the microalbuminuric group, compared with the normal patient group. HbA1c since diagnosis, mean blood pressure, lipoprotein(a), and apolipoprotein B did not correlate with albumin excretion rate, after controlling for other variables. Our findings highlight the continuing need for strategies to prevent smoking in this age group.

The usefulness of human placental lactogen and keratin immunohistochemistry in the assessment of tissue from purported intrauterine pregnancies.

This study compared conventional light microscopy with immunohistochemistry in the histopathologic diagnosis of intrauterine pregnancy in curettings in which fetal parts and chorionic villi were absent. Hematoxylin and eosin-stained sections of the curettings, which were from 50 consecutive patients in whom incomplete abortion had been diagnosed clinically, were circulated to four pathologists who graded their diagnoses with a confidence score. Immunohistochemical examination using a standard streptavidin-biotin-peroxidase method with anti-HPL and antikeratin antisera was performed. The pathologists in the maternity hospitals achieved a high level of diagnostic confidence compared with those working in the general hospitals. However, there were erroneous diagnoses by the one pathologist in the former group and none by the latter. Critical path analysis showed that the best performing pathologist could accurately diagnose all but two of the cases that had been diagnosed with a degree of doubt by the other pathologists without recourse to immunohistochemical examination. These results suggest that immunohistochemistry may be used discriminately in uncertain cases or if relatively inexperienced pathologists are reporting.

Improved performance in a prenatal screening programme for Down's syndrome incorporating serum-free hCG subunit analyses.

A prenatal screening programme for Down's syndrome potentially detecting 76 per cent of affected pregnancies in the South Australian general population at an amniocentesis rate of 3.9 per cent was designed following analysis of mid-trimester serum samples from 57 women who carried an affected fetus. This equates to one affected pregnancy being detected for 41 chromosomal analyses performed. For the experimental series, 75.4 per cent of affected pregnancies were detected, while 4.1 per cent of control specimens produced estimated risk odds consistent with further action. A maternal risk odds of birth of a Down's syndrome fetus of 1:420 was taken as the decision value, which is the prevalence of Down's syndrome births to 35-year-old mothers in South Australia. This screening performance was achieved by investigating combinations of serum analytes not previously reported and by refining the calculation of maternal risk odds to include selective weighting of indicator analytes. Combination of the measurements of free alpha-subunits and beta-subunits of chorionic gonadotrophin, alpha-fetoprotein, unconjugated oestriol, and placental lactogen was found to be most effective in indicating Down's syndrome fetuses. In all combinations of analytes tested, replacing the measurements of free alpha-subunits and free beta-subunits of chorionic gonadotrophin with the measurement of intact chorionic gonadotropin produced a less effective screen.

Epidemiology of Down syndrome in South Australia, 1960-89.

During 1960-89 687 Down syndrome live births and 46 Down syndrome pregnancy terminations were identified in South Australia. Ascertainment was estimated to be virtually complete. The sex distribution of Down syndrome live births was found to be statistically different from the non-Down syndrome live-birth sex distribution (P less than .01). Smoothed maternal age-specific incidence was derived using both maternal age calculated to the nearest month and a discontinuous-slope regression model. The incidence of Down syndrome at birth for the study period was estimated to be 1.186 Down syndrome births/1,000 live births. Annual population incidence was shown to be correlated with trends in the maternal age distribution of confinements. If current trends in the maternal age distribution of confinements continue, the population incidence of Down syndrome in South Australia is predicted to exceed 1.5 Down syndrome births/1,000 live births during the 1990-94 quinquennium.

A maternal serum screen for trisomy 18: an extension of maternal serum screening for Down syndrome.

The feasibility of extending second-trimester maternal blood screening for Down syndrome so as to include screening for trisomy 18 was examined using stored maternal serum samples collected for neural tube-defect screening. There were 12 samples from trisomy 18 pregnancies and 390 controls. The median maternal serum concentration of alpha-fetoprotein, free alpha-subunit human chorionic gonadotrophin, free beta-subunit human chorionic gonadotrophin, intact human chorionic gonadotrophin, total estriol, unconjugated estriol, estradiol, human placental lactogen, and progesterone were lowered in those pregnancies affected by trisomy 18 when compared with unaffected pregnancies matched for racial origin, maternal age, gestational age, and sample-storage duration. At an estimated odds risk of 1:400, 83.3% of affected pregnancies were detected using an algorithm which combines the maternal age-related risk with the maternal serum concentrations of unconjugated estriol, free alpha-subunit human chorionic gonadotrophin, free beta-subunit human chorionic gonadotrophin, estradiol, and human placental lactogen. The associated false-positive rate was 2.6%. At high risk odds of 1:10, the detection rate was 58.3%, with an associated false-positive rate of 0.3%. beta-Subunit human chorionic gonadotrophin and unconjugated estriol were the most powerful discriminators. It is possible to incorporate into existing Down syndrome screening programs an algorithm for detecting trisomy 18 with high sensitivity and specificity.