Maternal serum alpha-fetoprotein screening for open neural tube defects in twin pregnancies

Data on maternal serum alpha-fetoprotein (AFP) levels at 13-24 weeks' gestation in 46 twin pregnancies with open neural tube defects (22 with anencephaly, 24 with open spina bifida) and 169 unaffected twins were used to estimate the detection and false-positive rates associated with different cut-off levels. Using the conventional cut-off level of 2.5 multiples of the median (MoM) for unaffected singleton pregnancies of the same gestation and laboratory, the detection rate in twins was 99 per cent for anencephaly and 89 per cent for open spina bifida, with a false-positive rate of 30 per cent. Using a 5.0 MoM cut-off level to maintain a similar false-positive rate to that found among singleton pregnancies at 16-18 weeks' gestation (about 3 per cent), the detection rate was 83 per cent for anencephaly and 39 per cent for open spina bifida. Estimates are provided of the odds of having an affected twin pregnancy given a positive AFP result as well as the odds for individual women with a raised AFP level.

The effect of consanguinity on the reproductive wastage in the Turkish population

Analysis of data from 56,664 marriages in Turkey studied from 1970 to 1988 showed an overall rate of consanguineous marriages, of 21.25%, and increases in the rates of abortions, stillbirths, prenatal losses and neonatal deaths.

Consanguineous marriages in the Turkish population

This study of 55,175 marriages in Turkey, conducted from 1970 to 1987, showed an overall rate of consanguineous marriage of 21.21% (mostly first-cousin liaisons) and an inbreeding coefficient of 0.0064532. However, considerable differences between areas are apparent.

Evaluation and clinical application of a two-site immunoradiometric assay for alpha-1-foetoprotein using readily available reagents

The development and evaluation in routine clinical practice of a simple, rapid, high-throughput, immunoradiometric assay (IRMA) for alpha-foetoprotein (AFP) in serum and amniotic fluid is described. The assay uses readily available reagents; a radioiodinated mouse monoclonal antibody produced by the authors and the immunoglobulin G (IgG) fraction of a polyclonal sheep anti-human-AFP serum covalently linked to Sepharose CL-4B. Both antibodies are distributed by the Scottish Antibody Production Unit (Law Hospital, Carluke). The results of an extensive comparative trial between the IRMA and a radioimmunoassay (RIA) are presented. A high-dose 'hook' effect is not a problem in this system. Quantitative recovery was obtained, independent of the assay diluent. The IRMA has high sensitivity and a wide working range. Improved assay precision allowed a clinically significant change in the intervention limits.

Alternate form reliability and concurrent validity of the PPVT-R for referred rehabilitation agency adults

This study investigated the relationships among the Peabody Picture Vocabulary Test-Revised (PPVT-R) alternate forms and, also, the relationship of each PPVT-R form with the Wechsler Adult Intelligence Scale-Revised (WAIS-R) for a referred sample of 60 adult clients of the California State Department of Rehabilitation. Clients ranged in age from 18-3 to 37-7 (M = 25-7, SD = 5-9). PPVT-R alternate forms r = .88 was significant at p less than .001. Correlations with the WAIS-R VIQ were .82 for L, .78 for M; with PIQ, .46 for L, .38 for M; with FSIQ, .77 for L, .67 for M. All correlations with both forms of the PPVT-R were significant. PPVT-R mean scores did underestimate significantly all WAIS-R mean scores. Implications are discussed.