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Biomedical subjects

R Roberts

Publications and source records attributed to R Roberts.

At least 631 records · Page 35Linked to original sources
PubMed1970

Extraretinal light perception in the sparrow. 3. The eyes do not participate in photoperiodic photoreception.

Photoperiodic control of testis growth in Passer domesticus (house sparrow) is mediated entirely by extraretinal photoreceptors in the brain. The eyes do not participate in photoperiodically significant photoreception. Removal of the pineal organ does not affect either the response to light or, to a first approximation, the process of recrudescence. The intensity of light reaching the retina and that reaching the extraretinal photoreceptor were varied independently. This technique will make it possible to study brain photoreception in species of birds that will not tolerate blinding. Extreme caution is necessary in the interpretation of brain lesion experiments in which reproductive function is modified, since photoreception by brain receptors of unknown anatomical location affects testicular state.

Animals↗
PubMedDate not supplied

The use of intravenous nitroglycerin in cardiovascular disease.

The development of an intravenous form of nitroglycerin has further enhanced the role of nitrates in the therapy of cardiovascular disorders. This new preparation permits prompt initiation of therapy and rapid attainment of high systemic levels; because of its short half-life, rapid dose titration is both feasible and safe. The antianginal effects of intravenous nitroglycerin are useful in the treatment of coronary vasospasm and unstable angina pectoris. Its hemodynamic effects are of benefit in the therapy of congestive heart failure and in the control of peri-operative hypertension. Recent data suggest that, with appropriate monitoring, intravenous nitroglycerin can be safely administered to patients with evolving myocardial infarction to reduce the extent of myocardial damage.

Angina Pectoris, Variant↗
PubMedDate not supplied

Evaluation of myocardial infarction with enzymatic indices.

The severity of myocardial damage appears to be a common denominator contributing to electrophysiologic derangements, impaired ventricular function, and prognosis after myocardial infarction. Physiologically based models of processes affecting appearance and disappearance of CPK from the circulation may improve predictions and estimates of infarct size. Elevation of serum MB CPK isoenzyme activity appears to be a highly sensitive and specific indicator of myocardial injury. Despite the limitations discussed, recently developed enzymatic methods for detection, projection, and quantification of infarct dize have demonstrated that the extent of myocardial injury may be limited in selected patients by appropriate therapeutic measures. Further investigation may help to define the intervals between the onset of infarction and implementation of therapeutic maneuvers during which myocardial protection is possible, and may help to identify and differentiate inter ventions which salvage myocardium, those which improve cardiac performance without altering infarct size, and those which augment cardiac injury despite improving hemodynamics. Thus, in conjunction with electrophysiologic, radioisotopic, and hemodynamic techniques, enzymatic estimates and projection of infarct size should facilitate increased understanding of factors influencing the evolution of infarction and hasten development of effective therapeutic interventions designed to reduce myocardial damage.

Adsorption↗
PubMedDate not supplied

Wheelchair karate.

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Aged↗
PubMedDate not supplied

Poor adherence to placebo or amiodarone therapy predicts mortality: results from the CAMIAT study. Canadian Amiodarone Myocardial Infarction Arrhythmia Trial.

OBJECTIVE: This study examined the relationship between adherence, mortality, and psychosocial factors. METHODS: Subjects were 1141 patients participating in the Canadian Amiodarone Myocardial Infarction Arrhythmia Trial. Poor adherence to study medication (amiodarone or placebo), measured by pill count over 2 years, was defined as the lower 20th percentile of the pill count distribution. Predictors of adherence were also studied and included demographic and cardiac variables and, in a subset of participants (N = 671), measures of depression, distress, hostility, and social support. RESULTS: In survival analysis controlling for cardiac and demographic variables, poor adherence in the placebo and amiodarone groups was associated with an increased risk of sudden cardiac death (relative risk (RR) = 2.11, 95% confidence interval (CI) = 1.03-4.56, p < .05; and RR = 3.15, 95% CI = 1.34-7.44, p < .01, respectively), total cardiac mortality (RR = 2.04, 95% CI = 1.12-3.72, p < .02; and RR = 2.49, 95% CI = 1.32-4.72, p < .01, respectively), and all-cause mortality (RR = 2.25, 95% CI = 1.27-3.97, p < .001; and RR = 2.34, 95% CI = 1.32-4.17, p < .004, respectively). Logistic regression analysis identified two predictors of poor adherence to placebo: age > 70 years (odds ratio = 2.18, 95% CI = 1.11-4.29, p < .03) and social activities in the month before the index heart attack (odds ratio = 1.02, 95% CI = 1.00-1.04, p < .05). CONCLUSIONS: Poor adherence is associated with a greater risk of mortality. The relationship between adherence and social activities suggests a higher motivation to adhere to treatment in individuals more engaged in enjoyable activities.

Aged↗
PubMedDate not supplied

Depression and risk of sudden cardiac death after acute myocardial infarction: testing for the confounding effects of fatigue.

OBJECTIVES: This study examined the impact of depressive symptoms and social support on 2-year sudden cardiac death (SCD) risk, controlling for fatigue symptoms. METHODS: Myocardial infarction (MI) patients (N = 671) participating in the Canadian Amiodarone Myocardial Infarction Arrhythmia Trial completed measures of depression, hostility, and social support. RESULTS: After controlling for significant biological predictors, psychosocial predictors of increased SCD risk in the survival analysis were greater social network contacts (RR = 1.04; 95% CI = 1.01-1.06; p < .007), lower social participation (RR = 0.98; 95% CI = 0.96-1.00; p < .05), and, in placebo-treated patients, elevated depressive symptoms (RR = 2.45; 95% CI = 1.14-5.35; p < .02). Fatigue was associated with SCD (RR = 1.31; 95% CI = 1.11-1.53; p < .001), and, when included in the model, diminished the influence of depression (RR = 1.73; 95% CI = 0.75-3.98; p = .20). When the cognitive-affective depressive symptoms were examined separately from somatic symptoms, there was a trend for an association between cognitive-affective symptoms and SCD in placebo-treated patients after controlling for fatigue (RR = 1.09; 95% CI = 0.99-1.19, p < .06). CONCLUSIONS: Symptoms of depression and fatigue overlap in patients with MI. The trend for the cognitive-affective symptoms of depression to be associated with SCD risk, even after controlling for dyspnea/fatigue, suggests that the association between depression and mortality after AMI cannot be entirely explained as a confound of cardiac-related fatigue. The independent contribution of social participation suggests a role of both depressive symptomatology and social factors in influencing mortality risk after MI.

Activities of Daily Living↗
PubMedDate not supplied

Spinal cord swelling as a myelographic indicator of prognosis: a retrospective study in dogs with intervertebral disc disease and loss of deep pain perception.

The association of myelographic spinal cord swelling with neurological outcome was examined in 46 dogs with intervertebral disc disease and absence of deep pain perception (DPP). Spinal cord swelling was measured by calculating a ratio of the length of the loss of the myelographic dye column to the length of the second lumbar vertebra (L2). A positive neurological outcome was defined as return of voluntary motor function. A cut-off value for swelling:L2 of 5.0 was established by the creation of a receiver operator characteristic curve. Using a swelling:L2 ratio of 5.0 as a cutoff for indication of neurological recovery yielded a sensitivity of 74% and a specificity of 61%. Overall neurological recovery rate was 43%. Dogs with spinal cord swelling:L2 ratios less than 5.0 had a recovery rate of 61%, whereas dogs with a ratio greater than or equal to 5.0 had a recovery rate of 26%. Evaluation of these data by chi square analysis confirmed that a ratio less than 5.0 was associated with a positive outcome, and a ratio greater than or equal to 5.0 was associated with a negative outcome, (P < .05). Although other factors, such as duration of neurological signs, affect neurological outcome in dogs with no DPP, evaluation of myelographic spinal cord swelling can assist in establishing a prognosis.

Animals↗
PubMedDate not supplied

Localization of a gene responsible for arrhythmogenic right ventricular dysplasia to chromosome 3p23.

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD), a familial cardiomyopathy occurring with a prevalence of 1 in 5000, is characterized by replacement of myocytes with fatty and fibrous tissue. Clinical manifestations include structural and functional abnormalities of the right ventricle and arrhythmias, leading to a sudden death rate of 2.5% per year. Four loci have been mapped, but no gene has been identified as yet. METHODS AND RESULTS: We identified a large family of >200 members with ARVD segregating as an autosomal dominant trait affecting 10 living individuals. The diagnosis of ARVD was based on international diagnostic criteria including history, physical examination, ECG, echocardiogram, right ventricular angiogram, endomyocardial biopsy, and 24-hour ambulatory ECG. Blood was collected for DNA from 149 family members. Analysis of 257 polymorphic microsatellite markers by genetic linkage excluded previously known loci for ARVD and identified a novel locus at 3p23. Analysis of an additional 20 markers further defined the region. A peak logarithm of the odds score of 6.91 was obtained with marker D3S3613 at theta=0% recombination. Haplotype analysis identified a shared region between markers D3S3610 and D3S3659 of 9. 3 cM. CONCLUSIONS: A novel locus for ARVD has been mapped to 3p23 and the region narrowed to 9.3 cM. Identification of the gene will allow genetic screening and a specific diagnosis for a disease with protean nonspecific findings. It should also provide insight fundamental to understanding cardiac chamber-specific gene expression and/or the mechanism of myocyte apoptosis observed in this disease.

Adult↗
PubMedDate not supplied

Sexual assault on men.

Epidemiological data in 13 cases of sexual assault on men who attended a sexual assault referral centre are presented. All the assailants were male. The sexual orientation of the victims was predominantly heterosexual (7 of 13), 3 considered themselves to be homosexual and 3 were confused about their sexual orientation. The average age at the time of assault was 21.6 years. The most common form of assault was anal intercourse which occurred in 8 cases, followed by forced oral penetration which occurred in 6 cases. The proportion of known:unknown assailants (8:5) shows similar characteristics to those seen in female rape, use of weapons and multiple assailants were more common in assault on men. Seven men (54%) developed psychological problems following assault, and this was their main reason for presentation to the centre.

Adolescent↗