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Biomedical subjects

W Hall

Publications and source records attributed to W Hall.

At least 199 records · Page 11Linked to original sources
PubMed1991

Depression sub-typing: unitary, binary or arbitrary?

The strongest statistical support for the binary view of depression has been provided by factor (principal components) analytic studies which delineate a bipolar factor with features interpreted as reflecting "endogenous depression" and "neurotic depression" at opposing poles. We review the seminal studies to suggest instead that the bipolar factor has generally polarised depression and anxiety, and that no such entity or symptom complex of "neurotic depression" has been isolated. Instead "neurotic depression" has been defined principally by features of anxiety and personality style. We argue that the suggested entity is, in fact, a pseudo-entity, being no more than a residual group of non-depressive features without any significant intrinsic depressive characteristics. We support our interpretation by showing comparable solutions in published studies of depressives alone, contrasted with separate analyses of anxious and depressed patients. We also report two studies in which the "neurotic depressive" pole is made to appear and disappear by the inclusion and exclusion of anxiety items. As factor analytic studies have defined the "residual" pole so variably, we argue that some features held to distinguish neurotic depression are of no utility and that such a diagnosis is meaningless. We suggest that the clinician should not proceed (after excluding endogenous depression) to conclude that the default option is necessarily an entity "neurotic depression" and that instead a heterogeneous group of options (e.g. anxiety, personality disorder) require review. If the "neurotic depressive" type of the multivariate analytic studies is a pseudo-entity, then a modified unitary view of depression may be valid.

Adult↗
PubMed1990

Pathogenesis of a phleboviral infection (Punta Toro virus) in golden Syrian hamsters.

The hamster, Mesocricetus auratus, was examined as a possible model for investigating the poorly defined pathogenesis of the family Bunyaviridae, genus Phlebovirus. Punta Toro virus (PTV) isolates from Eastern Panama were highly virulent for two outbred and five inbred hamster strains, while isolates from western Panama were of low virulence. The Adames strain (eastern Panama) of PTV (LD50 approximately 1 PFU, sc) caused an acute fatal disease (average survival time, 3.8 days) in 10-week-old Lak: LVG (SYR) hamsters. Severe necrosis of the liver, spleen, and small intestine was associated with extensive expression of viral antigen in these organs. The Balliet strain (western Panama) of PTV (LD50 greater than 6 log10 PFU, subcutaneously) caused a mild hepatocellular infection with peak viral liver titers of 3-4 log10 PFU/g compared to 8-9 log10 PFU/g for the Adames strain. We observed histological lesions in the red pulp of the spleen or the lamina propria of the small intestine with the Adames strain. Lesions in the hamsters had characteristics of disseminated intravascular coagulation (DIC). The PTV-hamster model shares similarities to Rift Valley fever (phleboviral disease), which causes fatal disease in man and domesticated ruminants.

Animals↗
PubMed1990

Drug use, injecting practices and sexual behaviour of opioid users in Sydney, Australia.

This paper examines drug use, injection practices, and sexual behaviour in a sample of 100 opioid users, both in and out of current opiate treatment. Approximately three-quarters of subjects reported that they had used more than one illicit substance in the month prior to being interviewed. Needle sharing was common, with 29% of subjects having used a needle in the past month after it had been used by someone else, and 25% having passed on a needle after they had used it. The level of condom use was low, with 66.7% of subjects never having used a condom with their regular partner in the month prior to interview, and 20.7% of subjects who had engaged in sex with a casual partner during this period not having used a condom. Variables which were predictive of HIV risk-taking behaviour in relation to needle use were poly-drug use, not being in current treatment, and level of heroin use. Only age was predictive of risky sexual behaviour, with younger subjects being associated with more risk-taking behaviour. It was concluded that while opiate treatment was associated with lower levels of risky injecting practices, there was no association between treatment and safer sexual practices. Given the importance of sexual transmission of HIV more attention needs to be given to the sexual risk-taking behaviour of intravenous drug users.

Adult↗
PubMed1990

The drug market position of cocaine among young adults in Sydney.

A study was undertaken to explore the 'market position' of cocaine among young adults in Sydney, Australia. The intention was to estimate how likely Australia is to experience an epidemic of cocaine use if the availability of the drug was to increase. A sample of 499 young adults in which illicit drug users were overrepresented were surveyed. The results suggested that there was not a large untapped market for cocaine. In terms of risk and attraction, cocaine was perceived to be more like the traditional 'hard drugs' of heroin, stimulants and hallucinogens than the traditional 'soft drugs' of alcohol and marijuana. Only 5% of the sample were prepared to try cocaine if offered it by a close friend.

Adolescent↗
PubMed1990

On doing the "impossible": inferring that a putative causal relationship does not exist.

A simple heuristic is proposed for drawing a warranted inference that a causal relationship does not exist between two events. It is illustrated by a study of the putative indirect causal relationship between Autistic Disorder and the Fragile X syndrome. This study was designed to ensure that a failure to find such a relationship provided good reasons for concluding that it was unlikely there was a relationship between Autistic Disorder and the Fragile X syndrome.

Autistic Disorder↗
PubMed1989

Autism is not associated with the fragile X syndrome.

We provided a controlled test of the hypothesis that individuals with the Martin-Bell or Fragile X [fra(x)] syndrome are more autistic than mentally retarded control individuals. A sample of fra(x) individuals was obtained from the register of a clinical genetics unit and compared with mentally retarded control individuals selected from an assessment centre who were individually matched for age, sex, and IQ. A comparison of 45 pairs of fra(x) cases and control individuals on the DSM-III (R) criteria for autism and two standardized "instruments" for the assessment of autism (ABC and ADC) failed to find a higher prevalence of autism among fra(x) individuals. There was no statistically significant difference between fra(x) individuals and control individuals, and the mean differences on both the ABC and ADC scales were in the direction contrary to the hypothesis. An analysis of the study's statistical power suggested that it is unlikely the investigation failed to detect a large to medium difference between fra(x) individuals and control individuals in autistic behaviour. Subsidiary analyses of case-control differences showed that two autistic-like behaviours occurred at a higher rate among fra(x) individuals than other mentally retarded children, namely, gaze avoidance and hand flapping. These abnormalities may have misled clinicians into thinking that autism and fra(x) are associated.

Adolescent↗
PubMed1989

Barbara Snell Dohrenwend memorial lecture. The impact of AIDS on a gay community: changes in sexual behavior, substance use, and mental health.

This report describes progress made to date on a study of the impact of the AIDS epidemic on the gay community of New York City. Using a model of the life stress process described by Barbara Dohrenwend and her colleagues, the AIDS epidemic was conceptualized as a community stressor resulting in two key stress-inducing events: death of loved ones due to AIDS and potential illness and death of oneself due to infection with human immunodeficiency virus (HIV). It was hypothesized that these stressors would be significantly related to three domains of health outcomes: sexual behavior, drug and alcohol use, and psychological distress. Descriptive trends over time are provided for both the health outcome variables and the stressor variables. Cross-sectional analyses for 3 years of data provide evidence in support of the main hypothesis. The implications of these findings are discussed from the standpoints of methodology, public health, and the psychology of stress processes in community settings.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Comparison of protective immunity and inflammatory responses of pigs following immunization with different Actinobacillus pleuropneumoniae preparations with and without adjuvants.

Three experiments were performed to evaluate the inflammatory response, the antibody response and protection from experimental challenge of various Actinobacillus pleuropneumoniae serotype 5 (Ap5) vaccines in swine. In the first experiment, subcutaneous injections of either a water-in-oil (W/O) emulsion or Freund's complete adjuvant (FCA) caused lesions at the site of injection, while intraperitoneal injection of the W/O emulsion caused no lesions. In the second experiment, intraperitoneal (IP) injection of a W/O emulsion containing unwashed Ap5 cells (6-h culture) and/or supernates from a 24-h culture resulted in severe peritoneal lesions, while W/O emulsion containing PBS-washed Ap5 cells resulted in minimal peritoneal lesions. Ap5 alone or W/O alone failed to cause peritoneal lesions. The third experiment compared the antibody response and protection from challenge of pigs immunized with either 6-h PBS-washed Ap5 cells emulsified in oil - IP, 6-hour Ap5 cells adjuvanted with dimethyl diodacyl ammonium bromide - IP, Ap5 antigen alone - IP, a commercial vaccine - subcutaneously or saline - IP. All groups, except the saline-treated group, responded with high antibody titers to Ap5 2 weeks following vaccination; however, titers from the W/O plus antigen group were significantly higher than the three other groups (P less than 0.05). Following intranasal challenge with Ap5, all animals responded with increased antibody titers. All pigs were euthanized 10 days after challenge and evaluated for pneumonia and the lungs cultured for bacteria. The lungs of all pigs, excepting the W/O plus antigen group, contained pneumonic lesions and A. pleuropneumoniae was cultured from these lesions. These results, along with results from other groups, suggest that intraperitoneal immunization using oil-adjuvanted vaccine may be an effective method for protecting pigs from pneumonia due to A. pleuropneumoniae. Its efficacy may be due to stimulation of local respiratory mucosal immunity.

Actinobacillus↗
PubMed1989

The logic of a controversy: the case of Agent Orange in Australia.

Since 1979 the Vietnam Veterans' Association of Australia (VVAA) has claimed that exposure to the herbicide Agent Orange in Vietnam has adversely affected the health of Vietnam veterans and their families. A campaign for government recognition of diseases and disabilities caused by herbicide exposure led in 1983 to the appointment of the Evatt Royal Commission which, after a 2-year inquiry, comprehensively rejected the VVAA's claim. The Evatt Commission's findings have not been accepted by the VVAA and the claim continues to be defended, albeit in a highly qualified form. This controversy exemplifies the way in which a claim can attract public support, and persist despite rejections by Committees of Inquiry. An understanding of the reasons for the persistence of controversy requires an understanding of the logic of rejecting causal claims, the psychology of everyday inductive reasoning, and the interaction between politics and science.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1989

Ichthyosis, deafness, and Hirschsprung's disease.

An infant with congenital ichthyosis and deafness developed Hirschsprung's disease. No evidence of keratitis was present. No previous cases of ichthyosis have been associated with aganglionic megacolon. Although no corneal changes were observed, we believe that the clinical features of ichthyosis and deafness suggest the diagnosis of KID (keratitis, ichthyosis, deafness) syndrome. Whether corneal changes would have occurred is unknown, since the infant died of malnutrition and infectious complications.

Deafness↗
PubMed1989

Life events, life difficulties and confiding relationships in the depressed elderly.

A total of 101 elderly depressed patients and 85 community residents (matched for age and sex) were interviewed about life events, difficulties, and confiding relationships. Significantly more of the depressed sample reported at least one severe event in the three months before the onset of their illness. Lack of a good confiding relationship was associated with depression in men but not in women. In this relatively affluent Australian sample, life difficulties were rare and, probably as a result, were not significantly associated with depression.

Aged↗
PubMed1989

The limitations of multivariate statistical methods in the mensuration of human misery.

Multivariate statistical methods have been widely used in the analysis of the multiple symptom data which are routinely collected in psychiatric research on the classification of depressive illnesses. The most commonly used methods, those of factor analysis and discriminant function analysis, were introduced into research on the classification of depressive illness with unreasonably high expectations about what they could achieve. The failure to realize these expectations has produced scepticism in some quarters about the usefulness of multivariate methods in psychiatric research. When evaluated more circumspectly, multivariate statistical methods have made a contribution to our understanding of depressive illnesses, and they will continue to do so, if they are used with more reasonable expectations.

Analysis of Variance↗
PubMed1989

Behaviour completion mechanisms, anxiety and agoraphobia.

Little attention has been paid to the situations which provoke the initial attack of anxiety in agoraphobia. According to the behaviour completion hypothesis many normal subjects experience increased tension in such situations when there is a delay in the completion of a behaviour. One hundred and eight medical students completed a questionnaire designed to investigate this hypothesis. They reported experiencing increased tension or anxiety significantly more frequently in situations provoking agoraphobia when the situations contained a component of delay, as compared to such situations without this component, or to situations not commonly provoking agoraphobia. It is proposed that tension, anxiety and panic form a continuum of increasing levels of arousal, but are associated with different cognitions. It is further proposed that the arousal level of agoraphobics is sensitized, so that delay which provokes mild increases of arousal in the healthy, provokes high arousal in agoraphobics. This finding supports the hypothesis that delay in behaviour completion is a mechanism in the generation of tension and anxiety.

Adult↗
PubMed1988

'Repetition strain injury': an Australian epidemic of upper limb pain.

An analysis is provided of a recent Australian epidemic of an upper limb regional pain syndrome known as 'repetition strain injury' (RSI). 'RSI' was originally attributed to occupational over-use of the upper limb and biomechanical and ergonomic solutions were sought. More sceptical commentators argued that 'RSI' was an epidemic form of hysteria. More recently, a consensus has emerged that the epidemic is attributable to a combination of factors: a change in the perception of endemic symptoms of upper limb pain; the iatrogenic effects of the term 'RSI' and the methods used to manage it; and complications of the medico-legal process in which many sufferers became entangled.

Arm Injuries↗
PubMed1987

A simplified logic of causal inference.

This paper provides a simplified method for evaluating the evidence in favour of a causal claim. It analyses the evidence bearing upon such a claim in terms of two questions: Do the putative cause and effect covary, and can alternative non-causal explanations of the relationship be ruled out? The different research designs for assessing covariation are outlined, as are the ways in which these designs permit a researcher to decide between alternative explanations of the relationship.

Depressive Disorder↗
PubMed1987

Can localised brain impairment be simulated on neuropsychological test profiles?

We asked 28 registered nurses with varying degrees of experience in working with neurological and neurosurgical patients to fake results on 10 neuropsychological tests in such a way as to be congruent with a history of trauma to the left fronto-temporal cortex. We compared these data to those obtained from 21 patients who had been referred with verified cerebral injury and who had a diagnosis of left fronto-temporal dysfunction. The overall hit rate of classification for the two groups was 85.7% and 89.8%, depending on the way in which test scores were combined. Results showed that a knowledgeable group of informed fakers had great difficulty reproducing the test performance of individuals with left fronto-temporal impairment.

Adult↗