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Biomedical subjects

G A Chase

Publications and source records attributed to G A Chase.

At least 37 records · Page 2Linked to original sources
PubMed1996

Educating patients about cystic fibrosis carrier screening in a primary care setting.

OBJECTIVE: To assess the effectiveness of education about cystic fibrosis carrier screening in a primary care setting. DESIGN: Participants were asked to read a brochure, and were offered cystic fibrosis carrier screening. They were assessed for knowledge after reading the brochure and again after having an opportunity to ask questions and reread the brochure at home, at which time consent for testing was obtained. SETTING: Two sites of a health maintenance organization in the Baltimore, Md, area. PARTICIPANTS: Enrollees in a health maintenance organization aged 18 to 44 years. Of 608 enrollees approached, 477 completed an initial knowledge questionnaire, and 143 consented to testing. MAIN OUTCOME MEASURE: Change in knowledge score. RESULTS: Knowledge scores improved from a mean of 69% correct initially to 75% at the time of consent (P < 0.1, Student's paired t test). When participants were stratified by educational attainment, significant improvement was observed only for participants with no more than a high school education. However, their final knowledge score was significantly lower than that of college graduates. CONCLUSIONS: For people with more formal education, printed materials augmented by a chance to ask questions may be sufficient to ensure informed consent. For less well-educated persons, additional education may be necessary to ensure understanding of difficult concepts.

Adolescent↗
PubMed1995

In vivo D2 dopamine receptor density in psychotic and nonpsychotic patients with bipolar disorder.

BACKGROUND: A prior positron emission tomographic study from The Johns Hopkins University, Baltimore, Md, using N-methylspiperone labeled with carbon 11 reported elevated basal ganglia D2 dopamine receptor density (Bmax) values in neuroleptic-naive schizophrenic patients compared with controls. We have now extended these studies to include patients with bipolar disorder. METHODS: Patients with bipolar disorder (n = 14) either had never received neuroleptic medication or had been neuroleptic-free for more than 6 months, and they met DSM-III criteria for currently symptomatic affective disorder. Patients with bipolar disorder were compared with matched schizophrenic patients and normal controls. All received two positron emission tomographic scans, the second of which was preceded by oral administration of haloperidol lactate, to permit the calculation of D2 dopamine receptor Bmax. RESULTS: Diagnostic groups differed in Bmax by analysis of variance (P < .0001); post hoc tests showed higher Bmax values for psychotic patients with bipolar disorder and schizophrenic patients compared with normal controls and for schizophrenic patients and psychotic patients with bipolar disorder compared with nonpsychotic patients with bipolar disorder. Among patients with bipolar disorder, Bmax values correlated significantly with the severity of psychotic symptoms (r = .63) on the Present State Examination but not with the severity of nonpsychotic mood symptoms. CONCLUSIONS: We conclude that, like schizophrenic patients, patients with psychotic bipolar disorder have elevations of D2 dopamine receptor Bmax values and that such elevations in affective disorder are more closely associated with the presence of psychosis than with mood abnormality. Elevations in dopamine receptor values thus may occur in psychiatric states that are characterized by psychotic symptoms rather than being specific to schizophrenia.

Adult↗
PubMed1995

Use of exact and adjusted liability scores to detect genes affecting common traits.

We used the Haseman-Elston sib-pair test to screen for linkage of markers to genes for disease susceptibility in the simulated data as given in Problem 2 of GAW9. We applied the analysis to the underlying quantitative liability trait (Q1), other covariates of Q1 (Q2-Q4), and the dichotomous affection status trait. In addition, we analyzed the residual Q1 after adjusting for the covariates. Using the sib-pair linkage test, we identified a large region of chromosome 5 affecting the residual value of Q1, a region of chromosome 2 affecting Q3, and a region of chromosome 1 possibly affecting Q2. The analysis of the dichotomous traits did not reveal any regions to be significant. This is likely to be due to lack of information since the families were not selected through affected probands.

Analysis of Variance↗
PubMed1995

Should echocardiography be performed to assess effects of antihypertensive therapy? Test-retest reliability of echocardiography for measurement of left ventricular mass and function.

OBJECTIVES: The purpose of this study was to determine the test-retest stability of echocardiography for the measurement of left ventricular mass and function in patients with hypertension. BACKGROUND: Determination of changes in left ventricular mass may be impaired by study variability. The amount by which variables of mass and left ventricular function must change in an individual patient to exceed temporal variability has not been determined in a multicenter trial. METHODS: Ninety-six patients with hypertension had two-dimensional targeted, M-mode Doppler echocardiography repeated at 6 +/- 8 days by the same technician utilizing the same machine. Left ventricular mass and variables of systolic and diastolic function were measured. Test-retest reliability and the width of the 95% confidence intervals of variable change, as well as the contributions of age, study quality and body size to measurement reliability, were determined. RESULTS: Despite excellent reliability (intraclass coefficient of correlation 0.86), the 95% confidence interval width of a single replicate measurement of left ventricular mass was 59g, exceeding usual decreases in mass during treatment. Study quality, which was dependent on age and weight, influenced test reliability. Although the confidence interval width for ejection fraction was narrow (5 U), those for peak early (E) and late (A) diastolic velocities were wide, resulting in a confidence interval width for the E/A ratio of 1.5. CONCLUSIONS: The temporal variability, particularly in obese or elderly patients, or both, of echocardiography for measurement of left ventricular mass precludes its use to measure changes in mass of the magnitude likely to occur with therapy. Measurement stability is affected by study quality, and age and body weight both influence study quality. Although ejection fraction shows little temporal variability, the large width of the confidence interval of the Doppler E/A ratio impairs its use to serially measure diastolic function.

Age Factors↗
PubMed1995

Executive function in children with Tourette syndrome and/or attention deficit hyperactivity disorder.

Tourette Syndrome (TS) in children is associated with various neurobehavioral disorders including attention deficit hyperactivity disorder (ADHD). Children with TS and ADHD show some difficulties with neuropsychological tasks, but we do not know if children with TS alone have neuropsychological deficits. To assess specific cognitive differences among children with TS and/or ADHD, we administered a battery of neuropsychological tests, including 10 tasks related to executive function (EF), to 10 children with TS-only, 48 with ADHD-only, and 32 with TS + ADHD. Children in all groups could not efficiently produce output on a timed continuous performance task [Test of Variables of Attention (TOVA) mean reaction time and reaction time variability]. Children with TS-only appeared to have fewer EF impairments and significantly higher perceptual organization scores than children with TS + ADHD or ADHD-only. These findings suggest that deficiencies in choice reaction time and consistency of timed responses are common to all three groups, but children with TS-only have relatively less EF impairment than children with TS + ADHD or ADHD-only.

Adolescent↗
PubMed1995

Treatment with thyrotropin-releasing hormone (TRH) in patients with traumatic spinal cord injuries.

Numerous preclinical studies have demonstrated that posttraumatic treatment of spinal cord injury (SCI) with thyrotropin-releasing hormone (TRH) or TRH analogs improves long-term behavioral recovery. The purpose of the present study is to provide preliminary data regarding the safety and potential efficacy of TRH in patients with acute SCI. A total of 20 patients with SCI were classified by clinical examination into complete and incomplete injury groups within 12 h of trauma and randomly assigned in double-blinded fashion to treatment with either TRH (0.2 mg/kg intravenous bolus followed by 0.2 mg/kg/h infusion over 6 h) or vehicle (equal volume physiological saline) placebo. A variety of physiological variables were followed during treatment. Clinical examination included motor and sensory testing, as well as assigning a Sunnybrook score based upon level of function. Patients were examined at 24 h, 72 h, 1 week, 1 month, 4 months, and 12 months after injury. TRH infusions were well tolerated. There appeared to be no discernible treatment effect in patients with complete injuries although data were available from only six such patients at 4 months. For the incomplete injury group, a total of 6 treated and 5 placebo patients had 4-month evaluations. TRH treatment was associated with significantly higher motor, sensory, and Sunnybrook scores than placebo treatment. Because of patients lost to subsequent follow-up, 12-month data were not highly informative. These observations must be interpreted with considerable caution because of the small patient numbers, but together with extensive animal studies they support the need for a larger multicenter clinical trial of TRH.

Adult↗
PubMed1995

Trial of d-alpha-tocopherol in Huntington's disease.

OBJECTIVE: Evidence suggests that the neuropathology of Huntington's disease, a neuropsychiatric disorder due to a mutation on chromosome 4, results from excessive activation of glutamate-gated ion channels, which kills neurons by oxidative stress. Therefore, the authors hypothesized that alpha-tocopherol, which reduces oxyradical damage to cell membranes, might slow the course of Huntington's disease. METHOD: A prospective, double-blind; placebo-controlled study of high-dose d-alpha-tocopherol treatment was carried out with a cohort of 73 patients with Huntington's disease who were randomly assigned to either d-alpha-tocopherol or placebo. Patients were monitored for changes in neurologic and neuropsychologic symptoms. RESULTS: Treatment with d-alpha-tocopherol had no effect on neurologic and neuropsychiatric symptoms in the treatment group overall. However, post hoc analysis revealed a significant selective therapeutic effect on neurologic symptoms for patients early in the course of the disorder. CONCLUSIONS: Antioxidant therapy may slow the rate of motor decline early in the course of Huntington's disease.

Antioxidants↗
PubMed1994

Molecular-neurobehavioral associations in females with the fragile X full mutation.

In this study, young females with the fragile X [fra(X)] full mutation (fM) were assessed using quantitative measures of mutation amplification size (Amp) as well as the ratio of active normal X chromosome to total normal X chromosome (activation ratio-AR). Neurobehavioral assessments of females with the fM were performed and included specific and general measures of cognitive and behavioral/developmental functioning. To investigate molecular-behavioral associations, Amp and AR were used as independent variables, while cognitive and behavioral scores were used as dependent variables. Significant correlations were observed between both molecular variables (Amp and AR) and measures of cognitive functioning, with AR showing the most consistent and robust correlations. As AR increased, overall IQ and specific subtest and area scores from the cognitive tests increased. Conversely, as Amp increased, the overall IQ and specific subtest and area cognitive scores decreased. No significant associations were observed between AR or Amp and measures of behavior or development. The molecular-cognitive associations were generally consistent with the cognitive profile previously described in studies comparing females with fra(X) to age-matched controls. Amp and AR were not associated with one another, nor were they associated with the same cluster of cognitive measures. Though this report does not conclusively show that AR and Amp can be used to clinically assess the risk of a female with the fM for cognitive disability, the evidence presented does suggest that these molecular variables, especially AR, reflect important underlying genetic factors contributing to the fra(X) phenotype.

Adolescent↗
PubMed1994

Attitudes of physicians and genetics professionals toward cystic fibrosis carrier screening.

With the identification of the cystic fibrosis (CF) gene and its major mutations in 1989, there has been considerable debate among health professionals as to whether population-based carrier testing should be instituted. This paper presents the results of a survey to determine the attitudes of physicians and genetics professionals toward CF carrier testing. Factors associated with differences in attitudes also were examined. A questionnaire was mailed to primary care physicians and psychiatrists in 10 states who graduated from medical school between 1950 and 1985. For comparison, medical geneticists and genetic counselors in the same states also received the questionnaire. A total of 1,140 primary care physicians and psychiatrists (64.8%) and 280 medical geneticists and genetic counselors (79.1%) responded. Although 92% of respondents believed that a couple should be tested after asking about a test that detected 80% of carriers, only 43.9% of respondents believed such a test should be offered routinely. Those specialists most likely to have been involved in genetic services were most opposed to routine screening. The most important reason reported for opposition to routine screening was the consequences of an 80% detection rate. When presented with a hypothetical "error-free" test, 75.9% of respondents favored routine testing. Our findings suggest that there was little support for routinely offering the CF carrier test available at the time of this study among the physicians and professionals most involved in the provision of genetic services.

Attitude of Health Personnel↗
PubMed1994

Personality characteristics of the parents of autistic individuals.

Personality characteristics of 87 parents of autistic probands and 38 parents of Down's syndrome probands were examined using a standardized personality interview. Using best-estimate ratings derived from subject and informant interviews, parents of autistic individuals were rated significantly higher than controls on three characteristics: aloof, untactful and undemonstrative. When ratings were based on interviews with subjects only, parents of autistic probands were rated as significantly more aloof, untactful and unresponsive. There were no significant differences between parent groups on ratings based on informant interviews only. The implications of these findings for future family studies of autism are discussed.

Adolescent↗
PubMed1994

Influence of clinical subtype, sex, and lineality on age at onset of major affective disorder in a family sample.

OBJECTIVE: The authors analyzed data from a family sample ascertained for a genetic linkage study of bipolar disorder to address the following questions: Do the major clinical subtypes of familial affective disorder have distinct distributions of age at onset? What factors other than clinical subtype affect these distributions? After controlling for these factors, do the differences in age at onset persist among the subtypes? METHODS: Eighty-two families were ascertained through a treated proband with bipolar disorder who had a family history of two or more affected siblings or one affected sibling and one affected parent. After participating in an interview conducted by a psychiatrist using the Schedule for Affective Disorders and Schizophrenia--Lifetime Version, 274 probands and their first-degree relatives were diagnosed as having bipolar I, bipolar II, or recurrent unipolar disorder according to Research Diagnostic Criteria. Age at first major affective episode and other clinical data were collected. RESULTS: Onset age distributions were similar for bipolar I and bipolar II disorder but significantly different for recurrent unipolar disorder. This finding persisted after adjustment for a significantly earlier onset among females. Subjects with affective disorder in both parental lines (bilineal) also experienced a significantly earlier onset. Substance abuse, physical illness, and sex of the affected parent had no significant impact on onset age. CONCLUSIONS: Although differences in age at onset may reflect several factors, these results provide indirect support for the view that bipolar I and bipolar II disorders are genetically related phenotypes and suggest that bilineal families may be more complex than previously assumed.

Adolescent↗
PubMed1994

Decreased regional cortical gray matter volume in schizophrenia.

OBJECTIVE: The authors hypothesized that cortical gray matter volume reduction in schizophrenia is greatest in the heteromodal association cortex. This area comprises a highly integrated, reciprocally interconnected system that coordinates higher order cortical functions. METHOD: Total brain and regional gray matter volumes were calculated in 46 schizophrenic patients and 60 age and sex-matched comparison subjects by using magnetic resonance images. Disease specificity was examined by assessing 27 patients with bipolar disorder. Approximations to the dorsolateral prefrontal cortex, inferior parietal lobule, and superior temporal gyrus were selected as regions of interest for the heteromodal association cortex. Occipital and sensorimotor areas were used as comparison regions to test the hypothesis for regional specificity. RESULTS: Gray matter volume was reduced in schizophrenic patients in index regions even after covariance for overall brain volume, sex, and age. Bipolar disorder patients did not exhibit heteromodal gray matter reduction. Comparison regions did not differ among the three groups. Global gray matter volume was not different among groups after covariance for global brain volume. Comprehensive individual region post hoc analysis found no additional gray matter differences. CONCLUSIONS: These findings support the theory of disproportionate reduction of gray matter volume in the heteromodal association cortex specific to schizophrenia.

Adult↗
PubMed1994

Offering cystic fibrosis carrier screening to an HMO population: factors associated with utilization.

We offered cystic fibrosis (CF) carrier testing to reproductive-age enrollees in an HMO, in order to determine factors associated with test utilization in a primarily nonpregnant population. Male and female enrollees either were mailed an invitation to have the test after attending an educational session (N = 2,713) or were approached in waiting rooms at the HMO sites and given the opportunity to have the test without making an additional visit (N = 608). Uptake was considerably higher when testing could be obtained without making an additional visit (23.5%) than when attendance at an educational session was required as a prerequisite for having the test (3.7%). Utilization was higher among respondents who were planning children. Caucasians, and those with higher educational attainment. Among respondents planning to have children, individuals with higher tolerance for test uncertainty, lower fear of stigma, and higher perceived risk of being a carrier were significantly more likely to have the test. Testing decisions were not associated with the perceived burden of a child with CF or with the likelihood of aborting for CF. Although utilization of CF carrier testing is relatively low among nonpregnant individuals, uptake is significantly higher when testing can be obtained with minimal effort. Factors associated with the decision to be tested had more to do with implications of being a carrier per se than with the concerns of having a child with CF.

Adolescent↗
PubMed1993

Incorporation of genetics in primary care practice. Will physicians do the counseling and will they be directive?

OBJECTIVE: To determine, by response to a scenario, how willing primary care physicians would be to counsel a couple about prenatal diagnosis of cystic fibrosis and how directive they would be about whether the couple should undergo prenatal diagnosis and whether the couple should terminate the pregnancy if the fetus is affected. DESIGN: Survey of a random sample of primary care physicians, psychiatrists, and genetics professionals in 10 geographically representative states. RESPONDENTS: Sixty-five percent (N = 1140) of 1759 obstetricians, pediatricians, internists, family practitioners, and psychiatrists, and 79% (N = 280) of medical geneticists and genetic counselors. OUTCOMES AND RESULTS: Respondents were evenly divided on whether they would counsel about prenatal diagnosis or refer to a genetic counselor (49.4% and 50.6%, respectively). Those who indicated that they would counsel were likely to have greater knowledge about genetics, greater confidence in communicating about genetics, and higher tolerance for ambiguity and were more likely to have completed their medical training since 1971 and to practice in a rural area. Forty-four percent of physicians would give an opinion about prenatal diagnosis. Men would be more likely to give an opinion than women (P < .005). Only 9.6% of respondents would give an opinion regarding abortion. These respondents were more likely to come from specialties with less exposure to genetics and to value attendance at religious services. Primary care physicians were more likely to give their opinions about prenatal diagnosis and abortion than genetics professionals. CONCLUSIONS: To the extent that attitudes are reflected in practice, genetic counseling may be more directive when provided by primary care physicians than by genetics professionals, unless primary care physicians' growing involvement in genetics changes their attitudes.

Abortion, Eugenic↗
PubMed1993

The impact of some parameters on linkage analysis of Alzheimer's disease.

The two-point lod score linkage analysis of familial Alzheimer's disease is sensitive to the parameters of age-dependent penetrance rate, phenocopy rate, heterogeneity, and marker gene frequency. If unsuitable parameters are used, it may lead to false negative evidence against linkage. However, it is clear that, in some cases, it may lead to false positive evidence of linkage.

Adult↗
PubMed1993

Quantitative D2 dopamine receptor PET and structural MRI changes in late-onset schizophrenia.

Late-onset schizophrenia (LOS) is likely a syndrome of diverse etiology. In a series of related studies, we compared LOS patients with normal controls, elderly patients with early-onset schizophrenia (EOS), and Alzheimer's disease patients, using magnetic resonance imaging (MRI) and neuroreceptor positron emission tomography measures, which had previously been reported to be abnormal in EOS. EOS and LOS patients showed similar MRI changes. LOS drug-naive patients had elevated Bmax (receptor density) values for dopamine D2 receptors compared with age and gender norms, a phenomenon previously reported by our group in young schizophrenia patients.

Aged↗
PubMed1993

Physicians' knowledge of genetics and genetic tests.

PURPOSE: To assess primary care physicians' and psychiatrists' knowledge of genetics and genetic tests and the factors associated with differences in these physicians' knowledge. METHOD: Questionnaires were mailed in 1991 to 1,795 primary care physicians (family physicians, internists, pediatricians, obstetrician-gynecologists) and psychiatrists who had graduated from medical school between 1950 and 1985 (67.6% of the sample had graduated after 1970) and who were members of professional societies. The questions elicited demographic and practice characteristics as well as knowledge of genetics concepts and facts and awareness of the availability of genetic tests. To validate the questionnaire, 360 medical geneticists and genetic counselors received questionnaires. Statistical analysis involved arc-sine function transformation, t-tests, analyses of variance, F-tests, Tukey's HSD, and stepwise multiple regression. RESULTS: A total of 1,140 (64.8%) of the non-geneticist physicians responded. They correctly answered an average of 73.9%, SD, 13.9%, of the knowledge items, compared with 94.6%, SD, 4.2%, for the genetics professionals (p < .001). The most significant predictors of knowledge were recency of graduation from medical school and practicing in primary care specialties in which exposure to genetics problems is likely. Other significant predictors (from most to least important) were graduation from a U.S. medical school, willingness to adopt a new predictive test before it becomes standard practice, not using pharmaceutical companies as a source of information about new medical practices, and taking a required genetics course in medical school. CONCLUSIONS: The results suggest that knowledge of genetics and genetic tests is increasing among physicians, particularly among more recent graduates and physicians who are exposed to genetics problems in their practices, but deficiencies remain. Although a medical school course in genetics may improve knowledge, it is not sufficient. Greater emphasis is needed at all levels of medical education to reduce the chance of physician error as more genetic tests become available.

Analysis of Variance↗