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Biomedical subjects

S Vida

Publications and source records attributed to S Vida.

17 recordsLinked to original sources
PubMed1997

Accurate confidence intervals for measures of test performance.

The use of confidence intervals to estimate population parameters is briefly reviewed. Exact binomial confidence intervals can be calculated through the use of tables or statistical software packages. As an alternative, a microcomputer program to calculate sensitivity and specificity, point estimates and binomial confidence intervals for false-negative and -positive rate, positive and negative predictive power, prevalence of cases and non-cases, correct classification rate, and misclassification rate has also been developed. Characteristics of the computer program, 'AccuCon', which is available from the authors, are described.

Confidence Intervals↗
PubMed1994

An update on elder abuse and neglect.

Abuse and neglect of the elderly represent an important social problem in Canada. Forms of elder abuse and neglect include physical, psychological and material abuse; neglect, both intentional and unintentional; and violation of legal rights. The definitions, signs, and symptoms of elder abuse and neglect are discussed, as are estimates of incidence and prevalence, and descriptions of possible risk factors. The evolution of legislation regarding the reporting of elder abuse and neglect is reviewed, as are relevant areas of common law, the Civil Code, and the Criminal Code. This is followed by an overview of practical considerations in clinical management, and finally by recommendations for further research.

Aged↗
PubMed1993

A computer program for non-parametric receiver operating characteristic analysis.

Sensitivity and specificity are key measures of the performance of a given test in detecting a given disorder. For tests yielding numerical scores, sensitivity and specificity usually vary inversely over the range of theoretically possible cutoff scores, complicating the task of quantifying and comparing the diagnostic accuracy of tests. Receiver Operating Characteristic analysis (ROC) approaches this problem by plotting the curve of sensitivity versus 1-specificity for all possible cutoff scores of the test. The area under the ROC curve (AUC) can be used to describe the diagnostic accuracy of the test. Parametric and non-parametric methods exist that allow the calculation of the AUC and the comparison of tests. A disadvantage of parametric formulations is the assumption of a normal or Gaussian distribution of test scores. The present article presents a computer program that utilizes non-parametric formulations that do not require the normal distribution of test scores. The program calculates the sensitivity and specificity of a test at all possible cutoff scores, plots the ROC curve, calculates the AUC, its standard error and 95% confidence limits, and allows the comparison of tests on independent and correlated samples.

Confidence Intervals↗
PubMed1991

Behaviour problems of the mentally retarded.

The behaviour profiles of 176 mentally retarded individuals from two reception centres and nine group homes were assessed. The correlations between behaviour and age, sex, degree of mental retardation, etiology of mental retardation and medical diagnosis were assessed using the Revised Child Behaviour Profile. The severity of behaviour disturbance did not vary with age or medical diagnosis. The moderately retarded subjects presented with more severe behaviour problems, such as aggression, than the severely mentally retarded subjects. The variable most predictive of behavioural problems was etiology of the disorder. Individuals with Down's syndrome had significantly fewer behaviour disturbances and those with autism and pervasive developmental disorder had significantly more behaviour disturbances than other subjects. A psychiatric disorder was found in 10.2% of the sample. The implications of these findings are discussed with respect to public policy.

Activities of Daily Living↗
PubMed1989

DSM-III-R and the phenomenology of childhood bereavement: a review.

The literature on the phenomenology of childhood bereavement is reviewed. Several authors, particularly in the psychoanalytic literature, have suggested or supported the concept of "absence of grief" in children, based on the postulate that children are unable to tolerate the intense affects of mourning. More recently, systematic studies of nonclinical samples of bereaved children have found "absence of grief" to be uncommon, with most children in fact showing features such as sadness, crying, irritability, and a wide variety of other affective and behavioural symptoms. There does not appear to be a coherent syndrome of childhood bereavement, although tentative associations have been found between some phenomenological features and various child-related, family-related, societal, and circumstantial factors. The level of overall psychological adjustment after parental loss is both variable and controversial. Several tentative predictors of adverse reactions have been described. The possible place of childhood bereavement in current nosology is discussed. Preliminary evidence suggests that the phenomenology of childhood bereavement differs considerably from the DSM-III-R description of "uncomplicated bereavement." Recent evidence suggests that the DSM-III-R concept of uncomplicated bereavement needs to be expanded to include many of the affective and behavioural features of childhood bereavement, although confirmatory controlled research is required. Suggestions for improvement of research designs are made.

Adaptation, Psychological↗
PubMed1989

Canadian collaborative study of tetrahydroaminoacridine (THA) and lecithin treatment of Alzheimer's disease: effect on mood.

Several lines of evidence have implicated acetylcholine (ACh) as one of the neurotransmitters found to be decreased in Alzheimer's disease (AD). Various methods of cholinergic augmentation have been attempted, with mixed results. Tetrahydroaminoacridine (THA), an acetylcholinesterase inhibitor, is currently being investigated at the McGill Centre for Studies in Aging. Preliminary uncontrolled data from a 10-week clinical trial of THA and lecithin, reported elsewhere, suggest a clinically modest but statistically significant beneficial effect on cognition, although problems exist with side effects, particularly gastrointestinal. Since the suggestion by Janowsky in 1972 that cholinergic neurotransmission may exert an inhibitory or depressant effect on mood, the evidence accumulated in the literature has been inconclusive. We undertook to assess several potential pretreatment correlates of depressive symptoms in AD and to monitor the course of these symptoms during the 10 week treatment period, using the Geriatric Depression Scale (GDS) of Brink and Yesavage. Pretreatment GDS scores were found to correlate with degree of overall disability and dementia as measured by the Rapid Disability Rating Scale (RDRS) and the Mini Mental State Examination (MMS), respectively. GDS scores over the treatment period did not change to a statistically significant degree. The meaning of these results is discussed, particularly with reference to the difficulty of diagnosis and measurement of depression in the setting of dementia.

Aged↗
PubMed1982

Met-enkephalin inhibits mineralocorticoid production in isolated human aldosteronoma cells.

In vitro application of the morphinomimetic met-enkephalin resulted in inhibition of mineralocorticoid production by aldosterone-producing adenomas. Aldosterone, deoxycorticosterone, and corticosterone production by adrenocortical cells isolated from aldosteronomas has been studied under basal conditions and after stimulation with ACTH-(1-24). The blocking effect of met-enkephalin on the rate of aldosterone, deoxycorticosterone, and corticosterone release was significant at a concentration as low as 10(-11) M (P less than 0.001, P less than 0.01, and P less than 0.001, respectively). Dose-dependent inhibition of steroid biosynthesis became more apparent with increasing amounts of met-enkephalin in the incubation medium (10(-11)-10(-5) M); at a concentration of 10(-5) M, met-enkephalin decreased the production of aldosterone by 45%, that of deoxycorticosterone by 51%, and that of corticosterone by 44%. Increased steroid biosynthesis stimulated by ACTH-(1-24) was also significantly blocked by met-enkephalin. In a concentration of 10(-5) M, met-enkephalin produced significant decreases in aldosterone (P less than 0.001), deoxycorticosterone (P less than 0.05), and corticosterone (P less than 0.001) production compared to the peak values obtained after stimulation with 0.85 X 10(-10) M ACTH-(1-24). These data allow us to conclude that the inhibitory effect of met-enkephalin on mineralocorticoid production exerted at the level of the adrenals might be complementary to the factor(s) thought to be involved in the regulation of adrenal steroid production, playing a role similar to that of the biogenic amines originating in the adrenal medulla and regulating the adrenal cortex by a peripheral neurohumoral paracrine mechanism.

Adenoma↗
PubMed1980

[Structure of adrenal glands removed for hyperandrogenism and their hormone production in tissue culture].

Authors studied the surgically removed adrenals of a 16 year old girl with hyperandrogenism in tissue culture. The majority of cells in the initial culture was similar to the cells of the normal human adrenal. In the 6 weeks tissue culture the morphology of the cells has shown an alteration. The majority of them contained a small number of lipid droplets, abundant quantity of lysosomes and autophage vacuole. At this period in the media the progesterone level appeared to be elevated. Two months later in the tissue culture numerous transformed cells could be seen and the progesterone level of the media was low. It is believed that alteration of the biosynthesis of progesterone may have a role in the increased production of testosterone and in virilization.

Adolescent↗
PubMed1979

Corticosteroidogenesis by isolated human adrenal cells: effect of serotonin and serotonin antagonists.

The direct effect of serotonin and antiserotonin agents on adrenal steroid biosynthesis was studied in isolated adrenal cells derived from patients with Cushing's syndrome. The results indicate that serotonin increases corticosterone production, while the serotonin antagonists cyproheptadine and methysergide depress adrenal steroid - particularly cortisol and aldosterone - biosynthesis.

Adrenal Cortex↗
PubMedDate not supplied

Depression in Alzheimer's disease: receiver operating characteristic analysis of the Cornell Scale for Depression in Dementia and the Hamilton Depression Scale.

This study compares the performance of the Cornell Scale for Depression in Dementia (CSDD) and the Hamilton Depression Scale (HDS) in detecting Research Diagnostic Criteria (RDC) major depression in subjects with mild-to-moderate Alzheimer's disease (AD). Thirty-four subjects with this diagnosis and their caregivers were interviewed. The senior author conducted a diagnostic interview to determine RDC diagnosis. An investigator, blind to diagnosis, obtained demographic information and administered the Mini Mental State Examination, Global Deterioration Scale, CSDD and HDS. For each depression scale, the correlation with the RDC diagnosis of major depression was calculated, as were the sensitivity and specificity at various cutoff scores. Nonparametric receiver operating characteristic analysis was used to compare the performance of the two scales. The area under the receiver operating characteristic curve was .91 for the CSDD and .87 for the HDS. This differed from chance to a highly significant degree for both the CSDD and the HDS but the difference between the two scales was not statistically significant. Although the precision of the present study is limited by the small sample size, a cutpoint of 7 provided reasonable performance for both the CSDD and the HDS, yielding a sensitivity of .90 for both scales and a specificity of .75 for the CSDD and 0.63 for the HDS. Although the CSDD and the HDS are rating scales rather than diagnostic instruments, receiver operating characteristic analysis indicates that both demonstrate statistically significant discriminating ability for RDC major depression in mild to moderate, probable AD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Prevalence of depression in Alzheimer's disease and validity of Research Diagnostic Criteria.

This study was undertaken to estimate the point-prevalence of Research Diagnostic Criteria (RDC) depressive syndromes in Alzheimer's disease (AD) and to evaluate the validity of existing and potential alternative diagnostic criteria for major depression in the presence of probable AD. Twenty-six subjects with probable AD of mild to moderate severity and their caregivers were interviewed to estimate the prevalence of RDC depressive syndromes. For the evaluation of the validity of RDC for major depression, an additional 8 probable-AD subjects with suspected depression were added to the sample. Sensitivity, specificity, and correlation with diagnosis of RDC major depression were calculated for each diagnostic criterion, and existing major depressive criteria were compared to potential alternative criteria currently used for RDC minor depression. Of the subjects in our prevalence sample, 15.4% were found to have major depression; 23.1%, minor depression; and 11.5%, intermittent depression. In our validation sample, two criteria for major depression, self-reproach/guilt and thinking/concentration difficulty, were weakly associated with the final diagnosis of major depression because of poor sensitivity or specificity. In contrast, three possible alternative criteria were significantly associated with the diagnosis of major depression and showed high sensitivity and specificity. These included nonverbal manifestations of depression, irritability/complaining, and demandingness/dependency. We conclude that RDC depressive syndromes are common in probable AD of mild to moderate severity. In the presence of AD, the validity of some existing major depressive criteria may be limited in comparison to several potential alternative criteria because of relatively poor sensitivity and/or specificity.

Adult↗