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Biomedical subjects

A Tyler

Publications and source records attributed to A Tyler.

At least 19 recordsLinked to original sources
PubMed1997

Clinical experience with Tc-99m nofetumomab merpentan (Verluma) radioimmunoscintigraphy.

Tc-99m nofetumomab merpentan (Verluma), consisting of a Fab fragment of the pancarcinoma murine antibody NR-LU-10, has been previously evaluated as a diagnostic imaging agent in staging patients with lung cancer. The authors have taken advantage of the pancarcinoma reactivity of this antibody to select patients with a variety of carcinomas for radioimmunotherapy trials. These have included gastrointestinal, breast, ovary, pancreas, kidney, cervix, and bladder carcinoma. This article documents the range of tumor types and locations that can be identified by gamma camera imaging with this radioimmunoconjugate. Tumor was positively identified in 92% of 107 patients studied. In 15 patients, the images led to suspicion of previously unknown disease. The authors conclude that this radioimmunoconjugate is useful in assessing patients with advanced disease. Additional studies may be warranted to explore further the potential benefit of this diagnostic imaging agent in evaluating the extent of disease in patients with a variety of carcinomas.

Antibodies, Monoclonal↗
PubMed1993

Molecular analysis and clinical correlations of the Huntington's disease mutation.

The genetic mutation underlying Huntington's disease (HD) has been identified as an expansion and instability of a specific CAG repeat sequence in a gene (IT15) on chromosome 4. We have investigated the relation of the phenotype of HD to this molecular defect and assessed the feasibility of HD mutation analysis in diagnosis and prediction. Analysis of DNA from 449 HD patients (351 familial and 98 apparently isolated cases) revealed the mutation in more than 95% of patients from both groups. No molecular difference was found between patients presenting with psychiatric symptoms and those in whom chorea or other motor defects were the principal features; additionally, there was a wide range of age at onset for any specific repeat number, though the small group with juvenile onset and presenting with rigidity showed the largest expansions. The findings suggest that molecular analysis will be an accurate and specific diagnostic test for HD and valuable in presymptomatic detection in individuals at risk. However, such testing will require considerable caution to avoid serious difficulties; the well-established guidelines developed for the use of linked markers in relation to the prediction of HD should continue to be followed, though they will require reassessment in relation to use in diagnosis.

Adult↗
PubMed1993

Huntington's disease: predictive testing and the molecular genetics laboratory.

We describe the laboratory-related aspects of a series of 40 completed presymptomatic tests for Huntington's disease, using linked DNA markers. Pedigree structure and marker heterozygosity are shown to be important factors, both in the number of laboratory analyses required to give an informative situation and the residual uncertainty of the final estimate. Specific problems encountered by the testing laboratory are described, with possible ways of avoiding them, and the close links required between laboratory and clinical staff are emphasised.

Adult↗
PubMed1992

Presymptomatic testing for Huntington's disease in the United Kingdom. The United Kingdom Huntington's Disease Prediction Consortium.

OBJECTIVE: To evaluate the United Kingdom Huntington's disease presymptomatic testing programme. DESIGN: Postal questionnaire survey to collect data on all tests performed by clinical genetics centres between 1987 and 1990. SETTING: Genetic centres providing presymptomatic testing in the United Kingdom. SUBJECTS: 248 subjects at risk of Huntington's disease who had presymptomatic testing at their request. MAIN OUTCOME MEASURES: Sex, age, prior risk, and risk after testing. RESULTS: The risk of carrying the Huntington disease gene was reduced for 151 (61%) of the applicants and raised for 97 (39%). 158 (64%) of the subjects were female and 90 (36%) male. The median age at which the results were given was 32.5 years. CONCLUSIONS: The demand for testing was lower than expected and may have reached its peak in 1990. The excess of low risk results was not fully explained by the age effect. All the genetics centres concerned have agreed a common service protocol which requires extensive pre-test counselling and post-test follow up. The worth of the procedure remains to be decided. The availability of a large body of pooled data from all the United Kingdom testing centres, which individually are likely to have only a few results, will form a valuable resource for monitoring the long term psychosocial impact of testing.

Adolescent↗
PubMed1992

Presymptomatic testing for Huntington's disease in Wales 1987-90.

Between 1987 and 1990 a large series of at-risk individuals has been referred to our Huntington's disease (HD) presymptomatic testing programme. A detailed protocol for assessment and counselling has been followed. Out of 238 serious inquiries, 36% were potentially suitable for the testing programme, but 19% chose not to continue. Reasons for exclusion included the presence of clinical features of HD and being under the age of 18 years. Out of 40 final results given to 38 individuals, 23 indicated a lowered risk, 11 an increased risk, while five results were uninformative, two of these becoming informative on repeat testing. This series contained more women than men, and was disproportionately from the higher socio-economic groups. Motives for requesting a test principally related to child-bearing, informing existing children, and planning for the future. No significant psychiatric symptoms have been reported in the short term, but difficult counselling problems were presented by the high proportion of applicants who already showed clinical signs of HD. It is concluded that a detailed counselling protocol is essential in testing for HD, as many applicants are ill-prepared; this will assume even greater importance when the HD gene is identified and a test for specific mutations is available. The experience of presymptomatic testing for HD provides important general lessons which are likely to be applicable to other inherited neurological and psychiatric disorders.

Adaptation, Psychological↗
PubMed1990

Use of derivational morphology during reading.

This study examines contrasting predictions made by models of the lexicon in which stem morphemes play a central accessing role versus models in which stem morphemes play no particular role. Models which assign an independent role to morphemes predict that derivationally suffixed words have both inhibitive and facilitative effects on the reading process. A reading comprehension task was administered to good and poor high-school-age readers to assess their use of both the lexical-semantic and syntactic information provided by morphemes in derivationally suffixed target words. The subjects appeared to use the stem morpheme of a derivationally suffixed word to establish overall sentence meaning but often did not use the syntactic information contained in the derivational suffix. The failure to use syntactic information in the suffix was significantly greater for lower-ability readers than for those reading at or above grade level. The results offer support for morphologically organized models of the lexicon.

Concept Formation↗
PubMed1990

National symposium on problems of presymptomatic testing for Huntington's disease, Cardiff.

Presymptomatic testing for Huntington's disease has given rise to several ethical problems relating to such issues as confidentiality, the privacy of the individual, the testing of minors and informed consent in connection with blood sample donation. A multidisciplinary conference of staff from genetic centres involved with presymptomatic testing was organised in Cardiff to discuss these and other problems. Recommendations on good practice are described under four headings: pre- and post-test counselling; confidentiality in relation to test results; collection and storage of DNA, and criteria for testing.

Confidentiality↗
PubMed1990

Exclusion testing in pregnancy for Huntington's disease.

The results of DNA analysis are presented for a series of 90 couples, with one partner at 50% risk for Huntington's disease (HD), who were referred for exclusion testing in pregnancy over a three year period. Thirty-seven couples were studied in detail. The aims of the study were to evaluate attitudes towards prenatal testing, before pregnancy and afterwards, and the effectiveness of our counseling and methods of organising the service. Problems which could arise in relation to presymptomatic testing are documented. It is concluded that exclusion testing is a valuable form of prediction for some couples, particularly where family structure does not permit prediction for the person at risk. The need for intensive counselling was highlighted by the difficulties experienced by many couples in understanding how the test worked. Particular ethical and organisational problems may arise which require careful consideration beforehand and some recommendations are made. The proportion of couples who will continue to request exclusion testing as pre-symptomatic testing becomes more widely applicable remains unknown.

Adult↗
PubMed1989

Problems in genetic prediction for Huntington's disease.

Experience with nearly 300 applicants for predictive testing for Huntington's disease has shown that apart from the expected problems such as those related to third-party interests and the effects of an adverse test result, there were several less foreseen difficulties. These included the finding that some applicants were already clinically affected, requests for testing of minors, unintentional risk alteration for relatives, and the use of research samples for service purposes. More of the problems involved clinical and counselling aspects rather than laboratory procedures.

Adolescent↗
PubMed1988

Population studies of Huntington's disease in Wales.

Long-term surveillance of Huntington's disease families living in South Wales has been undertaken since 1973. We report the updated data on prevalence and births in 101 kindreds. The trend in the births at risk of Huntington's disease has been compared with a control population in North Wales.

Cross-Sectional Studies↗
PubMed1987

Exclusion testing for Huntington's disease in pregnancy with a closely linked DNA marker.

55 couples where one partner was at 50% risk of Huntington's disease (HD) were investigated with a DNA probe closely linked to HD, with a view to exclusion testing in a future pregnancy. In 3 of 9 pregnancies so far, HD was excluded in the absence of recombination. In 3 the risk was raised to around 50%, and in 2 exclusion tests were uninformative. The remaining couple changed their minds about termination of the pregnancy and the test was therefore judged inappropriate.

Chorionic Villi↗