Screening for Down's syndrome.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to J Slack.
Explore the source record for details and available documents.
A prerequisite to an informed decision to undergo any screening or diagnostic test is knowledge about such a test. This study describes the development of a self-administered questionnaire to measure knowledge of prenatal tests, for use in studies concerning the uptake of these tests. Both the reliability (internal and test-retest) and predictive validity are evaluated. Validity is assessed in two studies: first, comparison is made between three criterion groups (two with experience of pregnancy, one without); and second, scores on the questionnaire are compared before and after women have been provided with information about possible tests. The results show this to be both a reliable and valid measure of knowledge about prenatal tests. The results also highlight aspects of knowledge that are lacking. For example, a sizeable minority of women were uncertain or incorrect in identifying which tests they had undergone in a recent pregnancy.
A study of 20 Jewish and four non-Jewish kindreds transmitting factor XI deficiency (164 individuals) confirmed inheritance to be autosomal with severe deficiency in homozygotes (mean factor XI level 3.8 u/dl, SD 2.91) and partial deficiency in heterozygotes (mean factor XI level 57 u/dl, SD 10.42; normal mean factor XI level 96 u/dl, SD 11.6). The probability of an individual being heterozygous can be predicted from the factor XI level using a graph derived from this data. The accuracy is increased by including the prior probability derived from the pedigree. A high frequency of heterozygote to heterozygote mating was observed in the Jewish families consistent with an estimated gene frequency of 13.4% in this racial group. The relationship between factor XI level and bleeding tendency is poor; a third of heterozygotes had bled excessively after surgery, including six with factor XI levels above 50 u/dl, showing this condition to have clear signs of expression in heterozygotes. The lower limit of the normal range (2 SDs from the mean) was found to be 72 u/dl.
Explore the source record for details and available documents.
The direct and indirect costs and benefits of expanding the existing screening programme for Down's syndrome by using maternal age and serum alpha fetoprotein concentrations have been calculated using an ascertainment of Down's syndrome pregnancies from the North East Thames Regions in 1982. In addition, a possible approach to evaluating the total costs and benefits to the families concerned is presented. If the uptake of the proposed screening programme is maximal, the replacement rate is zero and a discount rate of 5% is used, the benefit cost ratio is 23.6. If the uptake of the programme is 50%, the replacement rate is 100% and a discount rate of 7% is used, the benefit cost ratio is 12.2. The proposed screening programme, based upon a risk of Down's syndrome of at least 1 in 220 using maternal age and serum alpha fetoprotein is both equitable for families at risk and of economic benefit to both families and society.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The suggested strategies for a screening programme for Down's syndrome by maternal serum alpha fetoprotein concentration were examined and tested on the experience of the North East Thames Regional. Screening by maternal serum alpha fetoprotein concentration may be used to identify pregnancies at increased risk, but this is useful only in women aged over 32 whose collective risk is greater than one in 200. The absolute probability of carrying babies with Down's syndrome for individuals in this high risk group can then be calculated and used to decide whether further diagnosis by amniocentesis is desired.
A mortality study was performed to determine death rates from coronary and cerebrovascular pathology in 180 patients with gout and their families. Lipid profiles were also analysed. Neither male nor female gout patients after presentation to hospital nor their male or female first-degree relatives were found to have an increased risk of dying from coronary artery or cerebrovascular disease. Families of hyperlipidaemic gout patients had a slightly increased incidence among males of death from coronary artery disease, a finding which may reflect the hypercholesterolaemia found among these relatives. It could have influenced the vascular mortality rate in families of hyperlipidaemic gout patients without any relationship to the diagnosis of gout itself.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A family study was performed to determine whether the hypertriglyceridaemia associated with gout is present in families of gout patients or due to the life style of the patient himself. The study revealed the expected hypertriglyceridaemia in gout patients; this was reflected by elevated serum levels of prebetalipoproteins and with reduction in the proportion of beta-lipoprotein. None of these abnormalities were seen in the first-degree relatives. Furthermore, the proportion of high-density lipoproteins was not significantly raised in gout patients.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The biosynthesis and efflux of sterols from cells into the medium were investigated in skin fibroblasts from a control, a patient with obligate heterozygous familial hypercholesterolaemia and a patient with the homozygous condition. The behaviour of the cells was studied in two lipid free media (lipoprotein deficient and delipidated serum), with and without the addition of low density lipoproteins (LDL) in order to find experimental conditions which showed maximum differences between the three cell lines. Incorporation of [14C]acetate into sterols in the presence (repression) and absence (induction) of LDL was similar in the normal and heterozygous cells, whereas the homozygous cells showed reduced repression and increased induction. In all three cell lines induction of sterol synthesis was greater with delipidated than lipoprotein deficient serum. The efflux of sterols in both the presence and absence of LDL did not differ between the three cell lines, but it was greater when LDL was added to the medium and when delipidated serum was used. Sterol biosynthesis and efflux from the cells of the heterozygote did not differ significantly from those of the control.
Explore the source record for details and available documents.
Explore the source record for details and available documents.