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P A Boyd

Publications and source records attributed to P A Boyd.

At least 19 recordsLinked to original sources
PubMed1999

Attitudes toward colon cancer gene testing: survey of relatives of colon cancer patients.

OBJECTIVES: Various studies have identified psychosocial factors that may influence attitudes toward colon cancer gene testing. Whereas family history of colon cancer has been associated with interest in gene testing, this has not been examined extensively. We hypothesized that the strength of family history of colon cancer is associated with risk perception and willingness to undergo gene testing. MATERIALS AND METHODS: We evaluated attitudes toward colon cancer gene testing among persons who had at least one first-degree relative with colon cancer. A total of 2680 at-risk relatives in 863 kindreds were identified and mailed an extensive survey regarding sociodemographic variables, family history, health behaviors and knowledge, and willingness to take a colon cancer gene test. A total of 56.6% of persons completed and returned surveys. We conducted a brief telephone survey of a random sample of 200 persons who did not respond to the mail survey. RESULTS: The combined study sample of 1373 people was 42% male, had a mean age of 55 +/- 15 years, was 96% white, and had moderate-to-high SES. A total of 77.4% were very likely to take the gene test, and 92.4% were somewhat or very likely to take the gene test. A total of 78% of the sample perceived a higher colon cancer risk, although patterns of risk perception and worry differed significantly between mail survey and telephone survey respondents. More of the telephone survey respondents were also somewhat unlikely or very unlikely to take the gene test compared to the mail survey respondents (13.7% versus 6.9%). In the combined sample, concern about developing colon cancer and risk perception increased with number of relatives with colon cancer (P < 0.0001). Eight percent expressed no concern about developing colon cancer; 4.8% felt their chance of developing colon cancer was lower than others of the same age, sex, and race; and 3.3% felt that they were very unlikely to develop colon cancer in their lifetime. However, there was strong interest in gene testing regardless of the number of affected relatives, and persons with more affected relatives were generally willing to pay more for the gene test (up to $1000). CONCLUSIONS: The strength of family history of colon cancer is associated with risk perception but not with willingness to undergo gene testing.

Aged↗
PubMed1998

6-year experience of prenatal diagnosis in an unselected population in Oxford, UK.

BACKGROUND: The benefits and harm associated with prenatal diagnosis are open to debate. We give a 6-year overview of the experience of one prenatal-diagnosis unit using a defined, unselected population. METHODS: All congenital malformations suspected prenatally and all congenital malformations, including chromosome anomalies, confirmed at birth were identified from the local Congenital Malformation Register. All fetuses or infants of women booked for delivery at the Oxford Women's Centre who had an OX postcode and date of delivery between 1991 and 1996 were eligible for the study. FINDINGS: 725 (2%) of 33,376 babies, were judged abnormal at delivery. 396 (55%) malformed fetuses and infants had been correctly identified prenatally. 174 fetuses had a suspected abnormality identified on scan and subsequently proved to be normal. 160 (92%) of these false-positive results were attributable to the reporting of so called ultrasound soft markers. Accuracy of ultrasound diagnosis was good for structural malformations. Ultrasound soft markers were responsible for a 4% increase in detection of malformations (from 51% to 55%) and a 12-fold increase in false-positive rate (one in 2332 to one in 188). 171 pregnancies (43% of prenatally diagnosed malformed babies) were terminated because of suspected abnormality. Suspicion of abnormality in these cases was first aroused after ultrasound scan in 136 (79%); chromosome analysis because of advanced maternal age, family history, or higher risk in biochemical screening test in 25 (15%); and molecular analysis of single gene defect because of family history in ten (6%). There was a 20% reduction in prevalence of conditions compatible with survival beyond the neonatal period because of termination of such pregnancies. INTERPRETATION: More than half of all malformed fetuses can be identified prenatally in routine practice, mostly following initial suspicion from ultrasound examination. Ultrasound soft markers lead to a small increase in detection of malformations but a large increase in false positives. Further research on the impact, including psychological, and value of markers is required to determine whether the benefits of reporting them exceeds the harm. Because methods and techniques continually change, ongoing surveillance of prenatal diagnostic services is vital.

Adult↗
PubMed1998

Outcome of prenatally diagnosed anterior abdominal wall defects.

One hundred consecutive cases of confirmed anterior abdominal wall defect, identified prenatally in the Oxford Prenatal Diagnosis Unit over 11 years, were studied. Fifty nine per cent of cases were suspected omphaloceles and 41% suspected gastroschisis. Fifty four per cent of omphaloceles were accompanied by other defects compared with 5% of those with gastroschisis. Overall, 29% of fetuses with omphalocele had an abnormal karyotype, and of those with another abnormality identified on scan (excluding four cases with no karyotype performed), 54% had an abnormal karyotype. Of the 27 cases with suspected isolated omphalocele, 14 were live born, all of whom have survived. If the 11 whose parents opted for termination of pregnancy are excluded, survival to birth was 88%. Six of the suspected isolated omphaloceles have Beckwith Wiedemann syndrome (BWS). Eight (57%) of the live born babies with omphaloceles had major problems up to the age of 2, but only one (7%) has long term major problems. This child has BWS and is deaf. Of the 39 cases of suspected isolated gastroschisis, 33 (85%) pregnancies resulted in live birth and one in neonatal death after surgery. Survival rate (excluding terminated pregnancies) was 97%. Gastroschisis was associated with a younger maternal age than omphalocele (p < 0.001) and lower birthweight centile (p < 0.01). Fifteen per cent of the gastroschisis babies had major problems up to the age of 2 years and 12% long term developmental problems. Ninety three per cent of the omphalocele babies and 88% of those who had gastroschisis have no long term problems. Over the study period there have been major changes in scanning equipment and expertise. Since 1991 no woman with a suspected isolated lesion has opted for termination of pregnancy.

Abnormalities, Multiple↗
PubMed1998

Prenatal sonographic diagnosis of skeletal dysplasias--a report of the diagnostic and prognostic accuracy in 35 cases.

Sonographic assessment of the skeleton is a routine part of fetal anomaly scanning. We report a series of 35 cases seen during a 7-year interval in which a skeletal dysplasia was suspected prenatally. In seven (20 per cent) of the 35 cases, a specific diagnosis could not be made either pre- or postnatally. Follow-up was incomplete in one case. In 32 (91 per cent) of the 35 cases, prenatal sonographic examination correctly predicted the prognosis, although in only 11 (31 per cent) of the 35 cases was the suggested prenatal diagnosis proven to be correct. The difficulty of making an accurate prenatal sonographic diagnosis in fetuses with suspected skeletal dysplasias throughout gestation, especially in the third trimester, and the importance of comprehensive multidisciplinary postnatal assessment in these cases are emphasized.

Abortion, Induced↗
PubMed1997

Clinical and genetic heterogeneity in Meckel syndrome.

Meckel syndrome (MKS) is a lethal malformation syndrome characterised by posterior meningoencephalocele, polycystic kidneys, fibrotic changes of the liver, and polydactyly. We have previously shown a linkage to chromosome 17q in 17 Finnish Meckel families. In this study we have analysed one Italian, one Austrian (of Turkish origin) and three British MKS families (Caucasian, Pakistani, and Bangladeshi families) for linkage to the MKS locus on chromosome 17q22-q24. We did not observe co-segregation of the disease and marker haplotypes in the Austrian family or in the three British families, of which two represented classical MKS and one a slightly atypical MKS phenotype with longer survival of the patient. In the Italian family the affected and non-affected children did not share the same maternal chromosome and thus this family could represent the same allelic disease as the Finnish MKS families. These results suggest locus heterogeneity in Meckel syndrome--a feature previously suspected based on the highly variable clinical phenotype.

Abnormalities, Multiple↗
PubMed1996

Hydrogen peroxide and sequence-specific DNA damage in human cells.

Exposure of HeLa cells in monolayer culture to increasing concentrations of exogenously added H2O2 causes damage to cellular DNA. When the DNA is subsequently isolated from the non-apoptotic cells remaining in such cultures, evidence was obtained to suggest that the DNA damage elicited in intact cells was non-random and that certain nucleotide sequences associated with, or related to, the genes for heat shock protein 60 and catalase were more susceptible to damage than others. In contrast, these particular sequences were not specifically susceptible to damage when naked human DNA was exposed directly to H2O2 in vitro. On an overall comparative basis, sequences in the genes encoding catalase, alpha-1 antitrypsin and beta-actin appear more vulnerable to H2O2 in vivo, than sequences in H-ras and the P53 gene which seem surprisingly resistant.

Actins↗
PubMed1996

Genetic testing for cancer in children. Short-term psychological effect.

OBJECTIVE: To study the psychological effect of genetic testing in children. DESIGN: We evaluated the psychological effect of predictive genetic testing through surveys of children at risk for familial adenomatous polyposis. Their psychological state was assessed before testing and 3 months later. SETTING: A research clinic. PARTICIPANTS: A volunteer sample of 41 children, aged 6 to 16 years, and their parents. MAIN OUTCOME MEASURES: Self-report inventories of depression, anxiety, behavior problems, and competence. RESULTS: Nineteen children were found to have a gene mutation (mutation-positive) and 22 did not (mutation-negative). Their depression, anxiety, and behavior problem and competence scores remained in the normal range after testing. Also, parents' depression scores remained within normal limits at follow-up. There were subclinical changes, however. Mutation-positive children with affected mothers had significantly higher depression scores at follow-up. Also, regardless of test results, children with affected mothers had significantly increased anxiety scores after testing. In families with mutation-positive and mutation-negative children, familial adenomatous polyposis-unaffected parents experienced significantly increased depressive symptoms at follow-up. CONCLUSIONS: Predictive testing of children at risk for familial adenomatous polyposis did not lead to clinically significant psychological symptoms in tested children or their parents. However, it is premature to conclude that long-term follow-up will be equally favorable. Additional study will be needed to determine the families' understanding of the genetic information and the effect of the information on familial relationships.

Adenomatous Polyposis Coli↗
PubMed1996

Human heat shock protein gene polymorphisms and sudden infant death syndrome.

Comparison of the frequency of occurrence of restriction fragment length polymorphisms in control human DNAs and DNAs from infants dying from sudden infant death syndrome has indicated no significant difference in the case of restriction fragment length polymorphisms associated with the heat shock protein genes hsp70 and hsp90. A highly significant difference was detected, however, in the case of the specific restriction fragment length polymorphisms detected by an hsp60 gene probe in MspI digests.

Chaperonin 60↗
PubMed1996

Antenatal diagnosis of cystic hygroma or nuchal pad--report of 92 cases with follow up of survivors.

Information on the outcome of pregnancy was collected on 92 fetuses with cystic hygroma or nuchal pad, identified prenatally. Forty three (47% of the total) were associated with abnormal karyotype. Twenty five (27%) had normal karyotype but an additional abnormality was identified on ultrasound scan. There were 10 liveborn babies in this group of whom seven had significant problems postnatally. In twenty four (26%) cases the cystic hygroma or nuchal pad was an isolated finding. Seventeen (89% of those in which the pregnancy was electively continued) were liveborn and reported to be normal. Those with a normal karyotype, no other anomaly identified on antenatal scan, and smaller non-septate lesions have a good prognosis.

Adult↗
PubMed1996

Omphalocele and pericardial effusion: possible sonographic markers for the pentalogy of Cantrell or its variants.

BACKGROUND: The pentalogy of Cantrell consists of defects involving the diaphragm, abdominal wall, pericardium heart, and lower sternum. CASES: We report three cases of the pentalogy of Cantrell (variant form), involving an omphalocele complicated by an anterior diaphragmatic hernia. In two cases, a pericardial effusion was noted at antenatal scanning; the case without a pericardial effusion had an intact diaphragmatic pericardium at surgical repair. CONCLUSION: The presence of a pericardial effusion in association with an omphalocele should prompt a detailed search for other features of the pentalogy of Cantrell or its variants.

Abdominal Muscles↗
PubMed1995

Using decision analysis to compare policies for antenatal screening for Down's syndrome.

OBJECTIVE: To compare different screening policies for Down's syndrome across a broad range of outcomes, using decision analysis, with particular reference to the role of maternal serum testing. DESIGN: A decision tree was used to combine data from local sources and the medical literature to predict the likely frequency of several outcomes. Sensitivity analyses were used to test the robustness of the conclusions drawn. SETTING: Oxfordshire Health Authority. MAIN OUTCOME MEASURES: Live births with and without Down's syndrome; miscarriages with Down's syndrome; cases of Down's syndrome detected antenatally; amniocenteses performed (and associated miscarriages); direct NHS screening costs; number of women offered screening. RESULTS: Screening policies for Down's syndrome that include serum testing can produce better population outcomes than programmes that do not. Each option for screening for Down's syndrome that we considered had significant drawbacks. In Oxfordshire, offering serum testing to women of all ages would prevent the birth of approximately one more baby with Down's syndrome per year than would a policy of screening for women aged 30 years or more. The cost of preventing this one extra Down's birth would be one or two normal babies lost after amniocentesis, 4500 blood tests for young women (with the associated anxiety and counselling), approximately 200 false positive serum test results and amniocenteses (with the associated anxiety and distress), and 90,000 pounds for the extra tests, counselling, and amniocenteses. Opinions are divided as to which policy is the better option for the population. CONCLUSIONS: Decision analysis is a useful tool for determining the likely consequences of different policy options across a broad range of outcomes. This focuses debate and decision making on outcomes of care, which in turn makes it clear that the choice of screening programme for Down's syndrome depends on the relative importance ascribed to the different outcomes. If individuals' values vary widely it may be impossible to find one screening policy that meets the needs of all pregnant women.

Adult↗
PubMed1995

Unilateral injury of posterior parietal cortex and spatial learning in hooded rats.

The influences of bilateral or unilateral injuries within the posterior parietal cortex (PPC) upon spatial learning in a water maze were examined in three experiments. Place-learning and response-learning were investigated in a four-alley 'Greek-cross' shaped water maze with extra-maze visual cues available. No differences were detected on any of several measures sensitive to learning between the lesion groups on the place-learning task. Microanalysis of behavior within trials revealed that animals with either bilateral or right unilateral PPC injuries committed significantly more total errors, initial alley entrance ('reference memory') errors, and re-entry ('working memory') errors in the response-learning paradigm than did either the control or left PPC-injured rats. No differences were detected between the latter two groups on these measures. Unilateral lesions resulted in asymmetrical placing responses ipsilateral to the injury 10 days after surgery whereas bilateral injuries resulted in asymmetrical placing with mixed directionality. The acquisition of the response-learning problem in the absence of visual cues was studied on animals prepared with unilateral lesions and housed post-operatively either in isolation or in a 'complex environment.' In the absence of visual cues both right and left PPC-injured rats committed more errors than sham controls, and differential post-surgical housing did not attenuate these impairments. These same animals were trained on the landmark navigation task. Although no differences appeared between the lesion groups, a generalized but transient facilitation of learning was observed in animals housed in the 'complex' environment. Unilateral injuries placed in sham controls failed to disturb retention of the landmark navigation strategy. Because none of the PPC-injured animals were deficient in the landmark task, a result which is contrary to observations in other laboratories, the influence of post-surgical recovery interval upon acquisition of the landmark navigation strategy was explored. Animals were prepared with right PPC injuries and trained following either a 5 or 35 day recovery interval. Only those animals limited to the short recovery interval proved to have a spatial deficit in the landmark task. It is concluded that injuries in the PPC of either hemisphere disturb egocentric spatial functions. However, animals with left PPC injuries are able to compensate by using allocentric visual cues if they are available. It is due to the special role played by the right PPC in complex visuospatial functions that animals with this injury are unable to compensate.

Animals↗
PubMed1995

Maternal 3;13 chromosome insertion, with severe pre-eclampsia.

A previously healthy young primigravida suffered very severe pre-eclampsia and was delivered at 32 weeks gestation. The baby was growth retarded with dysmorphic features, and died aged 4 days. Chromosome analysis of the baby revealed partial trisomy 13 resulting from recombination within a maternal insertion of part of 13q into 3p. To date, the maternal insertion has been identified in a further three members of the family and may have contributed to a number of spontaneous abortions, stillbirths and neonatal deaths in other family members. The various possibilities for recombination and malsegregation are discussed. An association between pre-eclampsia and trisomy 13 has been reported previously. To our knowledge this present paper constitutes the first report of partial trisomy for 13q occurring with pre-eclampsia.

Adult↗
PubMed1995

Gene tests and counseling for colorectal cancer risk: lessons from familial polyposis.

Familial adenomatous polyposis (FAP) is a well-defined, inherited colorectal cancer syndrome due to mutations in the APC gene. Genetic counseling and predictive gene tests for FAP will likely be incorporated as a first step in risk assessment for this condition. Our experience with predictive gene testing for FAP sheds important light on the impact of such tests for families at risk for FAP or colorectal cancer. We counseled and tested 47 adults and 36 minors at risk for FAP. Gene test results changed the risk of FAP for a given individual from a priori 50% to essentially zero or 100%. These individuals and their family members were interviewed before and after disclosures of APC gene test results to examine issues related to patients' knowledge about FAP, risk perception, reasons for seeking gene testing, and anticipated meaning of the results. We found that the gene test is imbued with meaning beyond determination of gene status in families who choose gene testing. The at-risk patient has preformed, well-entrenched conceptions of what having FAP or colorectal cancer entails, and family relationships and identity may be strongly linked with disease or gene status. We have found that genetic testing of minors requires additional counseling considerations and effort to ensure their understanding of FAP and the gene test. Importantly, their understanding of the clinical and social meaning of the gene test result must be elicited. For all patients, the value of counseling includes reduction of uncertainty and adjustment of misperceptions. Genetic counseling guidelines for this emerging clinical service are presented.

Adenomatous Polyposis Coli↗