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Biomedical subjects

M Macintosh

Publications and source records attributed to M Macintosh.

8 recordsLinked to original sources
PubMed1998

Variation in biochemical screening for Down's syndrome in the United Kingdom.

A questionnaire survey was undertaken of all 73 laboratories performing Down's syndrome screening in 1995. An estimated 352,000 tests were performed representing 47% of maternities. Three-quarters of these tests have ultrasound dating information at the time of testing. The majority of laboratories (70%) commenced screening at 15 weeks of gestation or later, and there was considerable variation in the upper limit of screening (17 to 24 weeks). Eighty-six percent of laboratories screened all women regardless of age. The reported Down's syndrome risk was based on term in 85% of laboratories. There was an inconsistent approach to determining and reporting high risk for trisomy 18 (Edwards' syndrome): 5% reported risks on report forms and 42% notified the clinicians if the risk was considered to be raised.

Age Factors↗
PubMed1993

Low levels of amniotic fluid placental alkaline phosphatase in Down's syndrome.

OBJECTIVE: To investigate amniotic fluid placental alkaline phosphatase (PLAP) levels in normal and trisomy 21 pregnancies. DESIGN: Cross sectional study. SETTING: A tertiary referral prenatal diagnostic service. SUBJECTS: Three hundred and eleven women with singleton pregnancies of normal karyotype between 10 and 23 weeks gestation and 31 women with pregnancies associated with trisomy 21 Down's syndrome. OUTCOME MEASURES: PLAP levels were measured by immunoradiometric assay in amniotic fluid obtained by amniocentesis. RESULTS: Amniotic fluid PLAP was detectable from 12 weeks gestation and the median value rose to a peak of 4.57 iu/l at 18 weeks. Pregnancies associated with Down's syndrome had significantly lower levels with a median multiple of median (MoM) of 0.638, (U = 3374, P = 0.0016, 95% CI = 0.50, 0.89). For the 20 women with trisomy 21 pregnancies detected at 16 to 18 weeks, the median MoM was 0.482, (U = 3694, P = 0.0011, 95% CI = 0.37, 0.85). CONCLUSION: These data demonstrates that PLAP levels are reduced in the amniotic fluid of women carrying a fetus with trisomy 21.

Alkaline Phosphatase↗
PubMed1992

Biochemical composition of amniotic fluid and extraembryonic coelomic fluid in the first trimester of pregnancy.

OBJECTIVE: To determine the biochemical composition of amniotic fluid and extraembryonic coelomic fluid between 8 and 12 weeks gestation. DESIGN: Prospective observational study. SUBJECTS: 40 women with a normal pregnancy between 7 and 12 weeks gestation having termination of pregnancy. INTERVENTIONS: Before termination the women had a transvaginal ultrasound guided amniocentesis. Pure samples of amniotic fluid and extraembryonic coelomic fluid were obtained from each woman and standard biochemical variables were measured in each fluid sample immediately after collection. RESULTS: Levels of sodium, potassium and bicarbonate were significantly higher in amniotic fluid whilst chloride, urea, bilirubin, protein, albumin, glucose, creatinine, calcium and phosphate were present in higher concentrations in extraembryonic coelomic fluid. All differences in concentration were significant (P less than 0.05; unpaired t-test). No relation was demonstrated between electrolyte concentrations in amniotic fluid or coelomic fluid and stage of gestation. CONCLUSIONS: Amniotic fluid and extraembryonic coelomic fluid have a widely differing biochemical composition. The biological significance of these differences remains unexplained.

Amnion↗