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Biomedical subjects

M Bloch

Publications and source records attributed to M Bloch.

At least 19 recordsLinked to original sources
PubMed1992

The psychological consequences of predictive testing for Huntington's disease. Canadian Collaborative Study of Predictive Testing.

BACKGROUND: Advances in molecular genetics have led to the development of tests that can predict the risk of inheriting the genes for several adult-onset diseases. However, the psychological consequences of such testing are not well understood. METHODS: The 135 participants in the Canadian program of genetic testing to predict the risk of Huntington's disease were followed prospectively in three groups according to their test results: the increased-risk group (37 participants), the decreased-risk group (58 participants), and the group with no change in risk (the no-change group) (40 participants). All the participants received counseling before and after testing. Standard measures of psychological distress (the General Severity Index of the Symptom Check List 90-R), depression (the Beck Depression Inventory), and well-being (the General Well-Being Scale) were administered before genetic testing and again at intervals of 7 to 10 days, 6 months, and 12 months after the participants received their test results. RESULTS: At each follow-up assessment, the decreased-risk group had lower scores for distress than before testing (P < 0.001). The increased-risk group showed no significant change from base line on any follow-up measure, but over the year of study there were small linear declines (P < 0.023) for distress and depression. The no-change group had scores lower than at base line on the index of general well-being at each follow-up (P < or = 0.045). At the 12-month follow-up, both the increased-risk group and the decreased-risk group had lower scores for depression and higher scores for well-being than the no-change group (P < or = 0.049). CONCLUSIONS: Predictive testing for Huntington's disease has potential benefits for the psychological health of persons who receive results that indicate either an increase or a decrease in the risk of inheriting the gene for the disease.

Adult↗
PubMed1992

Predictive testing for Huntington disease in Canada: the experience of those receiving an increased risk.

Predictive testing for Huntington disease (HD) has been offered in some parts of Canada for nearly 5 years. Candidates who were expected to have a significant likelihood for psychological problems were those who received an increased risk for developing HD. Sixty-six persons have now received such an increased risk result. In this manuscript we describe in detail the experience of 4 such persons who were chosen to illustrate recurrent and common themes which have emerged during counselling, and to highlight the strategies of coping with this information. Themes include difficulties communicating about HD, defensive postures adopted in preparing for testing, ramifications of testing for the whole family, and the impact of being at high risk on the candidates' perception of the future. One candidate has had testing postponed due to active suicidal risk. Only a few candidates have expressed regret at taking the test and no person receiving an increased risk result has made a suicide attempt or required hospitalization. After receiving results, symptoms of depression and anxiety are most common in the first 2 months, but over 1 year, candidates, in general, have less depression but live with a heightened perception of the present. The potential risk of premature diagnosis of HD in an individual with an increased risk results is highlighted. The significant ramifications of testing for the relative are shown. The importance of communication as a means of establishing a social support network, as well as the hazards of open communication, are discussed. Longitudinal evaluation will provide much needed data on the long-term effects of living at increased risk for HD.

Adult↗
PubMed1992

Predictive testing for Huntington disease in Canada: adverse effects and unexpected results in those receiving a decreased risk.

By January 1, 1991, a total of 388 persons had enrolled in the Canadian collaborative study of predictive testing for Huntington disease (HD). Of these participants, 105 persons have been given a decreased risk result. Contrary to expectations, approximately 10% of persons with a decreased risk result have had psychological difficulties coping with their new status. Here, we describe the individual responses of 6 such persons and experimental themes emerging after following these persons for up to 2 years. Individuals who are more likely to suffer an adverse reaction to a decreased risk result include those persons who have made irreversible decisions based on the belief they would develop HD or those who had unrealistic overoptimistic expectations of the positive effects of a decreased risk result. In contrast to those receiving an increased risk result, the most vulnerable time for persons receiving a decreased risk result is between 2 and 12 months after learning the outcome. The need for assessment and counselling of participants in predictive testing programs, even when there is a decreased risk result, is emphasized.

Adult↗
PubMed1992

Hypouricemic effect of zuclopenthixol: a potential marker of drug compliance?

Twelve newly-admitted psychotic patients were treated with clinical doses of zuclopenthixol (ZPT). Plasma uric acid (PUA) was measured before and during treatment. ZPT reduced PUA in all the patients by an average of 29.6% (P < 0.0001). PUA levels during treatment correlated with those obtained before treatment (R = 0.871, P < 0.0002). PUA returned to initial levels on discontinuation of treatment. Uric acid excretion increased during treatment. It is concluded that ZPT is a potent uricosuric agent, capable of producing persistent hypouricemia while administered. Such hypouricemia might be a useful indicator of drug compliance.

Adult↗
PubMed1991

Correlates of diurnal sleep patterns in infants of adolescent and adult single mothers.

Sleep behavior has been related to both child and environmental factors, but the relative importance of these factors is not yet clear. This study was an examination of the relation of diurnal sleep patterns to perinatal risk, infant temperament, home environment, parenting stress, emotional support, and social class. Twenty-three adolescent and 23 single adult mothers and infants were assessed in the home at 4 and 12 months. Percent sleep during the night was most strongly related to parenting stress and variability of night sleep to emotional support. Emotional support mediated effects of stress at 4 months. Results support the value of clinical assessment of sleep behavior.

Adaptation, Psychological↗
PubMed1991

Inhibition of immune complex-induced enteropathy by three different platelet-activating factor receptor antagonists.

We previously showed that intravenous injection of rat anti-BSA-BSA complexes (IC) prepared in 5x antigen excess rapidly induced a striate pattern of serosal (to mucosal) hemorrhage and vascular congestion throughout the small intestine of the Sprague-Dawley rat. In this study, we tested the effect of three different platelet-activating factor (PAF) receptor antagonists on the development of lesions. L-652,731, a synthetic derivative of kadsurenone (at doses of 1.3-2.7 mg/kg), SRI 63-675, a substituted quinolinium compound (6.7-15 mg/kg), and WEB 2086, a thienotriazolodiazepine (5-25 mg/kg) were each capable of completely or partially inhibiting IC-induced enteropathy in the majority of animals tested. Pretreatment with WEB 2086 prevented IC-induced hemoconcentration but not neutropenia. The antagonists did not lower the level of blood complement nor interfere with the fall in complement induced by administration of IC. The ability of PAF receptor antagonists to completely or partially inhibit IC-induced small intestinal lesions suggests that endogenous PAF is a major mediator of IC-induced enteropathy.

Animals↗
PubMed1990

The use of older donor livers for hepatic transplantation.

The function and outcome of liver grafts from "older" donors (more than 50 years old) were compared with grafts from younger donors (less than 50 years old). Of 184 consecutive liver transplants, 23 grafts were from older donors (50.2-65.3 years, mean 54.3 years). The liver preservation period was short, averaging less than 4 hr with the maximum under 8 hr for the older grafts. The majority of livers were preserved with Collins' solution. All transplants were performed using consistent methods that had proved to be successful over time. The medical status of the patients who received the older and younger grafts was similar but a higher percentage of older grafts were transplanted into ABO blood group--incompatible recipients. Graft function--as determined by peak aminotransferase levels, duration of prolonged prothrombin time, retransplantation rate within 30 days and incidence of primary nonfunction--was not significantly different in older versus younger grafts. Actual 30-day graft survival was 86.9% in the older grafts and 85.1% in the younger grafts. Actuarial 1-year graft and patient survival rates were 65.0% and 71.4%, respectively, in recipients of older grafts and 68.8% and 75.6%, respectively, in recipients of younger grafts. It is concluded that donor livers older than 50 years can be transplanted with the same success as younger livers provided that other generally accepted donor criteria are satisfied and the preservation period is short. The upper age limit for liver donation is not yet known.

Age Factors↗
PubMed1990

Ethical and legal dilemmas arising during predictive testing for adult-onset disease: the experience of Huntington disease.

The goal of predictive testing is to modify the risk for currently healthy individuals to develop a genetic disease in the future. Such testing using polymorphic DNA markers has had major application in Huntington disease. The Canadian Collaborative Study of Predictive Testing for Huntington Disease has been guided by major principles of medical ethics, including autonomy, beneficence, confidentiality, and justice. Numerous ethical and legal dilemmas have arisen in this program, challenging these principles and occasionally casting them into conflict. The present report describes these dilemmas and offers our approach to resolving them. These issues will have relevance to predictive-testing programs for other adult-onset disorders.

Abortion, Eugenic↗
PubMed1990

Opinion: predictive testing for Huntington disease in childhood: challenges and implications.

Predictive testing for HD strongly highlights the need for autonomy and the need for each individual to decide about his or her willingness-or unwillingness-to obtain genetic information predictive of the future outcome. In respect of this principle, testing for minors should not be offered at the request of a third party, and prenatal testing which would result in the birth of a child at increased risk for HD should, where possible, be avoided. If we accede to the wishes of the parents for their children to be tested, we will have broken the primary principles of confidentiality, privacy, and individual justice that are owed to those children. This could be the thin edge of a wedge which could result in adoption agencies, educational institutions, insurance companies, and other third parties demanding genetic testing for another individual. Despite years of careful planning, predictive testing for HD is turning out to be more complex and challenging than ever expected. We need a great deal of care and concern in developing our response to this challenge. Careful long-term assessment and documentation of the impact of such testing is needed, so that the appropriate guidelines can be developed, guidelines which both protect families with HD and at the same time give individuals the opportunity to participate in predictive testing programs.

Adoption↗
PubMed1989

Predictive testing for Huntington disease: I. Description of a pilot project in British Columbia.

The discovery of DNA markers linked to the gene causing Huntington disease (HD) has allowed the development of predictive testing programs for persons at-risk. A pilot program was established in British Columbia in November 1986. Ninety-five persons are currently enrolled. The major objective of this project is to introduce and evaluate a protocol for the delivery of test results to persons at-risk for HD. The criteria for entry and details of the psychosocial assessment before and after receiving a modified risk are presented. The guidelines that are developed from this project will have major applications for predictive testing programs for other late onset autosomal dominant disorders.

British Columbia↗
PubMed1989

Predictive testing for Huntington disease: II. Demographic characteristics, life-style patterns, attitudes, and psychosocial assessments of the first fifty-one test candidates.

Predictive testing was offered to individuals at-risk for Huntington disease living within a 100-mile radius of Vancouver, BC. Ninety-five at-risk individuals, representing approximately 12.6% of eligible candidates in this area, have enrolled in its first 16 months. This paper reports on the psychosocial characteristics of the first 51 at-risk individuals to complete the initial assessment. Two-thirds of the candidates are female with a mean age 39.3 years. They derive from higher socioeconomic backgrounds. Reasons for taking the test included planning for the future, concern for their children, and reducing uncertainty. Only 29.4% of candidates would both desire prenatal testing and terminate a high-risk pregnancy. Results on the SCL 90(R), General Well-Being, and other scales indicate that the candidates' mental health is representative of the population, but as a group, they are more resourceful. The tests identified individuals who needed further assessment on the basis of previous and current psychiatric functioning and social support. No candidate was a high immediate suicidal risk. The process of personal assessment has had beneficial effects on personal growth. The self-selection of a healthy group of candidates emphasizes the need for continued assessment and support as possibly less healthy candidates register for predictive testing programs in the future.

Adaptation, Psychological↗
PubMed1989

Effect of fish-fat or beef-fat supplemented diet on immune complex-induced enteropathy in the rat.

In contrast to animals on a beef fat-supplemented diet (BFD), animals maintained on a fish fat-supplemented diet (FFD) incorporate increased amounts of eicosapentaenoic acid (EPA) into membrane phospholipids. Generation of lipid mediators from such tissues favors the formation of compounds with less pro-inflammatory activity than are derived from tissues poor in EPA. Nevertheless, the FFD has not had a uniformly beneficial effect on animal models of inflammatory diseases. We previously showed that intravenous injection of rat anti-BSA-BSA complexes (IC) prepared in 5x antigen excess rapidly induced a striate pattern of serosal (to mucosal) hemorrhage and vascular congestion throughout the small intestine. In this study, we tested the effect of a BFD and FFD on immune complex-induced enteropathy. After six (Expt. 1) or eight weeks (Expt. 2) on the diet, rats were injected with IC and the severity of serosal hyperemia in the small intestine was scored. In some FFD, no lesions were seen under conditions which elicited moderate to severe lesions in BFD rats. In Expt. 1 involving 22 rats and in Expt. 2 involving 28 rats, those on the FFD had a significantly lower composite lesional score compared to those on the BFD, p less than 0.005 and p less than 0.005, respectively. These results indicate that the FFD had a beneficial effect on IC-induced enteropathy. It is suggested that this effect of the FFD may be mediated primarily by a reduction in availability of platelet-activating factor.

Animals↗
PubMed1989

Social system responses to Huntington disease.

Huntington disease (HD) is an adultonset, genetic disorder with major psychosocial implications. Although many of the psychiatric symptoms of the disorder have been attributed to the HD gene, systems factors may also account for the disorder's manifestations. Three illustrative issues--patient preselection, the denial of symptom onset, and suicide induction--are discussed from the vantage point of family systems thinking. Recently developed capacity for presymptomatic testing of HD despite the current absence of treatment or cure makes it likely that family therapists increasingly will be involved in clinical work with individuals and families in which HD occurs.

Adaptation, Psychological↗
PubMed1989

Different options for prenatal testing for Huntington's disease using DNA probes.

The discovery of DNA markers closely linked to the gene for Huntington's disease (HD) has allowed development of predictive and prenatal testing programmes for HD. This report describes four different approaches to prenatal testing for HD which have arisen during a pilot predictive and prenatal testing program in British Columbia, Canada. In the first approach (exclusion testing), the at risk parent cannot or prefers not to learn of his/her HD status. Two other approaches involve definitive testing of a fetus when a parent is determined to be at increased risk to have inherited the HD gene or is affected with Huntington's disease. The fourth approach is a stepwise combination of the above two methods which we refer to as 'exclusion-definitive' testing. These different approaches introduce a variety of challenging counselling and ethical issues. The role of each approach to prenatal testing in the management of Huntington's disease awaits the results of this and other predictive and prenatal testing programmes.

Adult↗
PubMed1989

Pediatric organ donor maintenance: pathophysiologic derangements and nursing requirements.

A retrospective chart review was conducted of 26 organ donors to determine hemodynamic and metabolic derangements encountered and nursing requirements for donor organ maintenance. There were 15 boys and 11 girls with a mean age 6.57 +/- 5.46 years. Mean donor maintenance time was 10.5 +/- 6.7 hours. Cardiorespiratory derangements included hypotension in 16, hypertension in 6, arrhythmias in 17 (premature ventricular contraction in 4, bradycardia in 8, paroxysmal atrial tachycardia in 3, and ventricular tachycardia in 2), asystolic events in 5, pulmonary insufficiency in 6, anemia in 8, and thrombocytopenia in 8. Metabolic and hormonal derangements included hyperglycemia in 18, hypokalemia in 20, hyperkalemia in 4, hyponatremia in 3, hypernatremia in 17, metabolic acidosis in 10, and diabetes insipidus in 15. Hypothermia (temperature 33.3 degrees +/- 0.4 degrees C, mean +/- SD) occurred in 14 donors. The mean physiologic Stability Index score was 22.2 +/- 4.7 and mean Therapeutic Intervention Score was 46.7 +/- 5.8. Total number of nursing hours spent in donor maintenance was 424.5 hours. Therapies offered included diuretics in 10, sodium bicarbonate in 8, antibiotics in 6, insulin in 12, pitressin in 13, verapamil in 3, isoproterenol in 3, dopamine in 17, and intravenous potassium boluses in 14. Of the potential 26 donors, 46 kidneys, 8 hearts, 14 livers, 3 pancreas, and 9 corneas were retrieved in transplantable condition. With appropriate donor maintenance, organs suitable for transplantation can be retrieved despite significant pathophysiologic derangements. Physicians intending to provide donor support should be comfortable with invasive monitoring and cardiorespiratory support and be prepared to provide a nurse to patient ratio of 2:1 at the bedside.

Adolescent↗