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Biomedical subjects

I Schweitzer

Publications and source records attributed to I Schweitzer.

At least 55 records · Page 3Linked to original sources
PubMed1996

Clinical and magnetic resonance imaging correlates of hypothalamic-pituitary-adrenal axis function in depression and Alzheimer's disease.

BACKGROUND: An age-related dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is well recognised in animals, but still remains controversial in humans. There is increasing interest that raised corticosteroid levels, due to activation of the HPA axis, may cause both depressive symptoms and cognitive impairments. Steroid effects on cognition may be via the hippocampus, a major site of corticosteroid action and an important structure involved in learning and memory. METHOD: To investigate this further, we examined the relationship between the dexamethasone suppression test, cognitive function, depressive symptoms and hippocampal atrophy on magnetic resonance imaging (MRI) in 32 normal controls, 49 subjects with NINCDS/ADRDA Alzheimer's disease and 51 patients with DSM-III-R Major Depression. RESULTS: Controlling for differences in dexamethasone concentrations, post-dexamethasone cortisol levels were related to advancing age in controls and depressed subjects. However, among subjects with Alzheimer's disease, post-dexamethasone cortisol levels were independently associated with both minor depressive symptoms and hippocampal atrophy on MRI. CONCLUSION: An association between advancing age and increased HPA axis dysregulation is supported for controls and depressed subjects. In Alzheimer's disease, HPA axis changes were associated with depressive symptoms and hippocampal atrophy. Longitudinal studies are now needed to determine the causal direction of these associations.

Aged↗
PubMed1996

A prospective study of aggression among psychiatric patients in rehabilitation wards.

OBJECTIVE: The aim of the study was to determine, among patients in rehabilitation wards, the prevalence and nature of aggressive behaviour and the relationship between aggressive behaviour and patient characteristics and ward factors. METHOD: The aggressive behaviour of all 220 inpatients within the rehabilitation program of a large psychiatric hospital in Victoria was assessed using the Staff Observation Aggression Scale. RESULTS: Physical assaults occurred at a rate of 97.6 per 100 patients per year. About 40% of all incidents appeared to be unprovoked. Most physical incidents involved use of body parts and use of a weapon was uncommon. Aggression was most often directed at a staff member. Serious injury was rare. Aggressive behaviour was correlated with gender and duration of admission for the whole sample; however, there were different correlates of aggressive behaviour for different ward populations and different types of aggression. As for ward variables, time of day but not patient/staffing level was associated with aggressive behaviour. CONCLUSIONS: There was a high rate of aggressive behaviour among patients in rehabilitation wards; this should be taken into consideration in the planning of their community placement. The findings also caution against aggregating different ward populations and types of aggressive behaviour for research.

Adult↗
PubMed1995

Risk factors for recurrent emergency department visits for asthma.

BACKGROUND: Patients presenting with asthma to emergency departments have lost control of their disease, have significant airways obstruction, and frequently require admission to hospital. Although even one visit is not desirable, there is a more disturbing subgroup who repeatedly visit the emergency department. METHODS: To investigate the reasons for multiple emergency visits, a questionnaire was given to 448 consecutive patients presenting to the two largest adult emergency departments in Ottawa, Canada between November 1989 and April 1991. Within this cohort, those who had made at least three visits in the past year were compared with controls (only one visit in the past year). RESULTS: Although inhaled corticosteroid use increased with multiple visits (indicating increased asthma severity), only 60% of those visiting at least three times in the past year were taking inhaled corticosteroids. Chronic undermedication relative to disease severity was apparent among the cases. The number of visits was associated with nocturnal asthma on a regular basis, work and school absenteeism, frequent visits to their regular physician, and frequent admissions to hospital. Visits were not related to psychological health, environmental allergens/irritants, or lack of perceived asthma severity. CONCLUSIONS: The recommendations of current asthma guidelines are not reaching these patients. The issue of translating guidelines from paper to practice must be addressed before highly effective medications can have an important impact on the frequency of emergency department visits.

Adrenal Cortex Hormones↗
PubMed1995

Improved engraftment of human spleen cells in NOD/LtSz-scid/scid mice as compared with C.B-17-scid/scid mice.

T and B lymphocyte-deficient mice homozygous for the severe combined immunodeficiency (SCID) mutation can be immunologically engrafted with human lymphocytes. However, low levels of human peripheral blood mononuclear cell engraftment are commonly observed, impeding full use of this model. We now demonstrate that strain background in mice homozygous for the scid mutation is a strong determinant of levels of human lymphocyte engraftment. NOD/LtSz-scid/scid mice support higher levels of engraftment of both human spleen and peripheral blood mononuclear cells than do C.B-17-scid/scid mice. We observed, using human spleen cell injected scid mice, 1), high levels of engraftment of the host peripheral lymphoid tissues with human CD45+ (leukocytes), CD3+ (T cells), CD4+ (helper/inducer), and CD8+ (suppressor/cytotoxic) lymphoid cells for up to 24 weeks in NOD/LtSz-scid/scid mice; 2), migration of high numbers of human lymphocytes to peripheral lymphoid and nonlymphoid organs in NOD/LtSz-scid/scid, but not in C.B-17-scid/scid mice; 3), higher levels of serum immunoglobulin of human origin in NOD/LtSz-scid/scid mice than in C.B-17-scid/scid mice; 4), histological lesions characteristic of human anti-mouse xenoreactivity in NOD/LtSz-scid/scid mice; and 5), human origin antibodies against filarial antigens after engraftment with native human spleen cells. The use of NOD/LtSz-scid/scid mice as recipients to achieve significantly enhanced human lymphopoietic cell engraftment will now enable human immunity to be more easily studied in animal models.

Animals↗
PubMed1994

Cortisol suppression by dexamethasone in the healthy elderly: effects of age, dexamethasone levels, and cognitive function.

The effects of age, cognitive function (measured by Cambridge cognitive examination (CAM-COG) score); and dexamethasone (DEX) levels on the dexamethasone suppression test were studied in 33 healthy older subjects (age 51-96). Three subjects (9.1%) were nonsuppressors and were older and had lower CAMCOG scores than the 30 suppressors. Significant correlations were observed between natural log-transformed postdexamethasone cortisol (LNCOR) levels and age (r = 0.40) and CAMCOG score (r = -0.45). Multiple regression analysis was used to investigate the relationship between LNCOR, age, DEX levels, and CAMCOG score. Age and DEX combined explained 41% of the variance in LNCOR values, whereas CAMCOG score and DEX levels explained 44% variance. As age and CAMCOG were highly correlated (r = -0.72), both together did not significantly improve the fit of regression equation (47% variance explained). These findings suggest an association between advancing age, impaired glucocorticoid feedback, and cognitive dysfunction in healthy human subjects. Although any causal connection remains to be demonstrated, results would be consistent with the "glucocorticoid cascade" hypothesis of human aging.

Aged↗
PubMed1994

The differentiation of depression from dementia by temporal lobe magnetic resonance imaging.

Temporal lobe Magnetic Resonance Imaging (MRI) was performed in 43 patients with NINCDS/ADRDA Alzheimer's disease (AD) (33 probable, 7 possible, 3 definite) and 32 subjects with DSM-III-R Major Depression (DEP) matched for age, sex and level of education. Hippocampus (anterior and posterior, right and left), amygdala, entorhinal cortex, parahippocampal gyrus and cerebral cortex were rated for atrophy on a 4-point scale. Good discrimination between groups could be achieved using a cut-off of 2 or more on anterior hippocampal atrophy rating (sensitivity 93%; specificity 84%; 89% cases correctly grouped overall). Even among a subgroup of 9 mild AD subjects and 10 cognitively impaired DEP subjects (matched on mini-mental state score), the same cut-off correctly grouped 84% (16/19) cases. Hippocampal atrophy increased with age in both AD and DEP subjects leading to a reduction in specificity (but not sensitivity) for those aged over 75. Within the AD group a significant correlation was observed between length of history and atrophy of the entorhinal cortex (r = 0.39, P = 0.009). We conclude that temporal lobe atrophy on MRI can provide good discrimination between AD and DEP subjects, including those DEP patients with cognitive impairment apparent on screening tests of cognitive function.

Aged↗
PubMed1994

Volumetric and visual assessment of the mesial temporal structures in Alzheimer's disease.

BACKGROUND: Alzheimer's disease is the commonest cause of dementia. Clinical diagnosis of Alzheimer's disease may be difficult. Magnetic resonance imaging has a role to play in diagnosis. AIM: To assess whether volumetric and/or visual assessment of the mesial temporal structures is useful in separating patients with Alzheimer's disease from age matched controls. METHODS: Twenty-four patients with Alzheimer's disease diagnosed by NINCDS/ADRDA criteria and 15 age matched controls were studied with magnetic resonance imaging (MRI) and volumetric techniques. Segmented volumes of the mesial temporal structures were assessed visually and volumetrically. RESULTS: Volumetric analysis demonstrated significant (p < .001) differences between the two groups, but showed overlap in individual cases. Discriminant function analysis predicted correct group membership (patient or control) in 85% of cases. Visual assessment alone demonstrated a sensitivity of 92% and a specificity of 93% in distinguishing the Alzheimer patients from controls. CONCLUSION: Volumetric and visual assessment of the mesial temporal structures is useful in separating Alzheimer patients from controls. Overlap is present in individual cases. Visual assessment was as useful in separating the two groups as the volumetric analysis.

Aged↗
PubMed1994

The function of the hypothalamic-pituitary-adrenal axis in Alzheimer's disease. Response to insulin hypoglycaemia.

BACKGROUND: To investigate an association between HPA axis dysfunction, depression and cognitive impairment, we assessed subjects with mild Alzheimer's disease (AD). METHOD: Sixteen non-depressed subjects with AD according to NINCDS/ADRDA criteria and 18 normal controls underwent the insulin hypoglycaemia (IH) test and the dexamethasone suppression test (DST). RESULTS: The AD subjects showed a blunted response of adrenocorticotrophic hormone (ACTH) to IH compared with controls (P = 0.019). ACTH response (area under curve) correlated with a score for cognitive ability (CAMCOG) (r = 0.64, P < 0.01). AD subjects had a shorter time to peak cortisol level than controls (P = 0.004), although total cortisol response was normal. CONCLUSIONS: The AD subjects show evidence of adrenal hyper-responsiveness and normal immediate (rate-sensitive) glucocorticoid feedback. An association between HPA axis dysfunction and organic brain pathology in AD subjects may be mediated by cell loss in the hippocampus.

Adrenocorticotropic Hormone↗
PubMed1993

Preoperative prediction of pulmonary complications following thoracic surgery.

The ability of preoperative quality-of-life and physiologic variables to predict postoperative complications was tested in 117 consecutive patients undergoing thoracotomy for possible or definite lung cancer. Preoperatively, quality of life was globally assessed by the QLI and Sickness Impact Profile. Dyspnea was assessed by the Clinical Dyspnea Index and a modified Pneumoconiosis Research Unit question. Spirometry and maximal exercise testing were carried out in 115 and 46 subjects, respectively. Thirty-seven percent experienced at least one respiratory complication (eg, pneumonia, atelectasis prompting bronchoscopy, pulmonary embolism). Twofold or greater increases in respiratory complications were associated with current smoking (p < 0.05), cancer as the final pathologic condition (p < 0.10), at least moderate dyspnea (p < 0.10), FEV 1 < 60 percent of predicted (p < 0.05), ventilatory reserve < 25 L (p < 0.05), and VO2max < 1.25 L (p < 0.05). Twofold increases in the incidence of any complication (respiratory, cardiac, etc) were associated with age > or = 75 years (p < 0.05) and cancer as the final pathologic condition (p < 0.05). We conclude that simple historic information (age, smoking status, cancer status, dyspnea) indicates the risk of postoperative morbidity. General quality-of-life measures were not good predictors of morbidity. Our findings corroborate the few studies supporting the value of VO2max and suggest that the usefulness of the ventilatory reserve deserves further attention.

Activities of Daily Living↗
PubMed1992

Does forced air heating exacerbate asthma?

Asthma morbidity increases in the Canadian autumn coincident with the beginning of home heating. To test the hypothesis that forced air heating exacerbates asthma, 51 subjects were randomly assigned to one of two groups: the intervention (off1-on2) group was instructed to keep their home forced air heating off from September 9 to 17 and then to set the thermostat to 22 degrees C from 8 PM to 8 AM between September 18 and 25. The concurrent control (off1-off2) group was instructed to keep their forced air heating off during the entire study period. Forty-eight of the 51 subjects randomized recorded morning peak flows, asthma symptoms, and bronchodilator use during the study period. For the intervention group, results before compared with during home heating, respectively, were as follows: mean nocturnal awakenings 0.36 versus 0.36; any breathing difficulties an awakening 82% versus 73%; mean morning peak flows 406 lpm versus 409 lpm, a difference of 3.3% +/- 6.7% (SEM), p = 0.6. There was a 95% probability that the true change in peak flows with forced air was less than 2%. For the control group, the comparable results were as follows: mean nocturnal awakening 0.40 versus 0.47; breathing difficulties on awakening 40% versus 47%; mean morning peak flows 400 lpm versus 399 lpm (p = 0.9). The commencement of forced air heating did not exacerbate asthma in this clinical population and is therefore unlikely to be an important problem for most people suffering from asthma.

Adolescent↗
PubMed1992

Asthma management preceding an emergency department visit.

BACKGROUND: The burden of illness from asthma in North America has not decreased despite advancements in understanding disease pathogenesis and improved pharmacotherapeutics. This study examined the adequacy of preventive measures applied to asthma. METHODS: Using a standardized self-administered questionnaire, 111 consecutive patients presenting to the emergency department because of asthma were surveyed about their "usual" level of disability from asthma, usual medications, self-management plans to deal with an asthma attack, and environmental control measures. RESULTS: Twenty-five percent of subjects suffered sleep disturbance more than 15 days per month, had work/school attendance affected more than 14 days per year, and previously visited an emergency department twice in the past year. Thirty-seven percent had no effective plans to deal with an attack and another 32% had plans that were never discussed with a physician. Although 78% reported that cigarette smoke aggravated their asthma, one third of these were exposed at home. CONCLUSIONS: For a significant proportion of adults requiring emergency health services for asthma, preexisting management was poor by current standards. We recommend that patients be screened by emergency physicians and those with identifiable inadequacies in usual care be referred to physicians with expertise in asthma management.

Adult↗
PubMed1992

Chronic cough responsive to ibuprofen.

A 57-year-old woman believed that ibuprofen, prescribed for back pain, improved her idiopathic chronic cough that had been resistant to inhaled and oral corticosteroids. To confirm this observation, we performed an n-of-1 clinical trial with four treatment periods, each separated by a 4-day washout. Ibuprofen 1800 mg/day for 6 days or placebo was randomly allocated in a double-blind fashion with a block size of 4. The number of coughs during the first 30 minutes after awakening were counted daily throughout the study using a tape recorder. Sixty-two coughs/hour occurred while taking ibuprofen, compared with 164 with placebo. We conclude that ibuprofen may be effective in idiopathic chronic cough, and suggest that prostaglandins may be pathogenic factors in some patients.

Chronic Disease↗
PubMed1991

Plasma cortisol and 11-deoxycortisol activity in depressed patients and normal volunteers.

Plasma cortisol and 11-deoxycortisol were measured in 30 depressed patients and 110 normal volunteers before and after a 1.0 mg dexamethasone suppression test (DST). Post-dexamethasone plasma cortisol, 11-deoxycortisol and the cortisol/11-deoxycortisol ratio were significantly higher in the depressives compared to the controls, even when age and sex were taken into account. Pre-dexamethasone plasma cortisol, post-dexamethasone cortisol, 11-deoxycortisol and their ratio were significantly higher in the cortisol nonsuppressors than in the suppressors. The measurement of post-dexamethasone 11-deoxycortisol and the ratio did not differentiate between endogenous and reactive depression. Using the normative data, we explored several methods for determining a criterion value to define abnormal post-dexamethasone plasma 11-deoxycortisol and the cortisol/11-deoxycortisol ratio in depressed patients. All showed poor sensitivity and a low positive predictive value for depression. The measurement of 11-deoxycortisol thus does not enhance the clinical utility of the DST.

Adult↗
PubMed1990

Dexamethasone kinetics in depressed patients before and after clinical response.

Dexamethasone pharmacokinetics were measured in 19 depressed patients, 10 dexamethasone suppression test (DST) nonsuppressors and nine suppressors, following a 1 mg oral dose in tablet form at 2300 h. Median dexamethasone concentrations were significantly lower in the nonsuppressors from 3-16 hr post-administration. Nonsuppressors had a significantly lower area under the curve than suppressors, and plasma clearance was significantly faster in the nonsuppressors than in the suppressors. Eleven patients, six nonsuppressors and five suppressors, agreed to a repeat DST after clinical improvement when all six nonsuppressors had normal DST responses. There were no significant differences between the median dexamethasone concentrations, or any of the pharmacokinetic parameters measured, of the "normalising" nonsuppressors and the suppressors. Dexamethasone kinetics were altered in depressed nonsuppressors but became normal with remission of depressive symptoms and normalisation of the DST response.

Adult↗
PubMed1990

The dexamethasone suppression test in anorexia nervosa. The influence of weight, depression, adrenocorticotrophic hormone and dexamethasone.

When 20 female anorexic in-patients were investigated with weekly DSTs, 10 had an abnormal result at initial testing. There was no identifiable relationship between severity of weight loss and DST status; % ideal body weight was no different between suppressors and non-suppressors. There was no consistent relationship between normalisation of the DST response and weight gain. Depressive symptoms were common, with half the patients scoring 20 or more on the HRSD. Plasma ACTH concentrations before and after the DST were normal. There was a significant negative correlation between plasma dexamethasone concentrations and pre- and post-dexamethasone plasma cortisol concentrations.

Adrenocorticotropic Hormone↗
PubMed1990

Genital self-amputation and the Klingsor syndrome.

Two psychotic individuals, who performed acts of genital self-amputation, are presented. One of the patients had self-mutilated with the intention of suicide and had also in the past amputated his hand. Psychotic patients with delusions (often religious), sexual conflict associated with guilt, past suicide attempts or other self-destructive behaviour and depression, severe childhood deprivation, and major premorbid personality disorder, are the group at risk for genital self-amputation. It has been proposed that the eponym, the "Klingsor" syndrome, be applied only to acts of genital self-mutation, involving religious delusions. The author suggests that this syndrome should be expanded to include all cases of genital self-mutation resulting from a psychotic illness.

Abdominal Injuries↗