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Biomedical subjects

J P Michel

Publications and source records attributed to J P Michel.

At least 19 recordsLinked to original sources
PubMed2002

[Depression among the elderly in Switzerland].

Data for this analysis came from a cross-sectional study on dementia, depression, and disability conducted in Zurich and Geneva in 1995/96. The random sample stratified by age and gender consisted of 921 subjects aged 65 and more. Based on the Canberra Interview for the Elderly, depression was assessed by means of psychogeriatric assessment scales (PAS) according to DSM-III-R criteria. The number of depressive symptoms (NDS) and the prevalence rate of depression (PRD) were computed for the whole sample as well as according to age and gender. To evaluate the independent effects of age as well as gender with regard to the risk of being depressed, multivariate analyses were conducted. On average, 13% of females vs 8% of males reported having at least one depressive symptom. The PAS yielded 298 (41.8%) subjects without depressive symptoms, 341 (50.2%) with 1-3 symptoms, and 60 (8.0%) with four or more. The average NDS was 1.27 (95% CI 1.16-1.39). For females, NDS values statistically significantly higher than those for males were calculated (1.53, 95% CI 1.35-1.70 vs 1.05, 95% CI 0.90-1.20). The NDS increased significantly with age. Subjects with low education levels and being divorced or widowed had statistically significantly higher NDS values than highly educated, married, or single persons. There were strong positive associations between NDS, dementia, and activities of daily living. Multivariate regression analysis revealed gender - however, not age - as a strong risk factor for NDS. Overall PRD amounted to 8.0% (95% CI 5.7-10.2%). Females had statistically significantly higher PRD values than males (10.4%, 95% CI 7.0-13.9% vs 3.9, 95% CI 2.0-5.9%). The PRD increased substantially with age. After adjustment for other risk factors, multivariate logistic regression analysis confirmed the positive statistically significant association between age, gender, and depression.

Activities of Daily Living↗
PubMed2001

Structural determination of zinc dithiophosphates in lubricating oils by gas chromatography-mass spectrometry with electron impact and electron-capture negative ion chemical ionization.

Pentafluorobenzyl ester derivatives were used to identify zinc dialkyldithiophosphates and diaryldithiophosphates antiwear engine oil additives by GC-electron impact ionization (EI) MS and GC-electron-capture negative ion chemical ionization (ECNCI) MS analysis. GC-EI-MS of the dialkyldithiophosphate-pentafluorobenzyl derivatives afforded characteristic fragment ions corresponding to the cleavage of one and two alkyl radicals. In most cases, information was only obtained on one alkyl chain. Additional and complete information was obtained with retention time indices using synthetic derivatives and with GC-ECNCI-MS analysis. ECNCI afforded characteristic dithiophosphate anions which allowed the determination of the total number of carbon atoms in the alkyl radicals. The diastereoisomer mixtures of 2-hydroxy-sec.-alkyl radicals were completely separated on GC analysis.

Gas Chromatography-Mass Spectrometry↗
PubMed2001

[Dementia, depression and activity of daily living as risk factors for falls in elderly patients].

OBJECTIVES: Falls among elderly are a well-recognised public health problem. The purpose of the present study was to explore the relation between dementia, number of depressive symptoms, activities of daily living, setting, and risk of falling. METHODS: Data for the analysis came from a cross-sectional study about dementia, depression, and disabilities, carried out 1995/96 in Zurich and Geneva. The random sample stratified, by age and gender consisted of 921 subjects aged 65 and more. The interview was conducted by means of the Canberra interview for the Elderly, extended by short questionnaire. The subject was classified as a faller if the subject and/or the informant had reported a fall within the last 12 months prior to the interview. Logistic-regression analysis was used to determine the independent impact of dementia, depressive symptoms, and ADL-score on risk of falling. RESULTS: The stepwise logistic regression analysis has revealed a statistically significant association between dementia (OR 2.14, 95% CI 1.15-3.96), two resp. three depressive symptoms (OR 1.64, 95% CI 1.04-2.60) as well as four or more depressive symptoms (OR 2.64, 95% CI 1.39-5.02) and the risk of falling. There was no statistically significant relationship between studied risk factors and the risk of being one-time faller. However, we found a strong positive association between dementia (OR 3.92, 95% CI 1.75-8.79), four or more depressive symptoms (OR 3.90, 95% CI 1.55-9.83) and the risk of being recurrent faller. Moreover, residents of nursing homes (OR 8.50, 95% CI 2.18-33.22) and elderly aged 85 or more (OR 2.29, 95% CI 1.08-4.87) were under statistically significant higher risk of sustaining recurrent falls. CONCLUSIONS: The results of the present study confirm that dementia and depression substantially increase the risk of falling.

Accidental Falls↗
PubMed2001

Economic considerations of Alzheimer's disease and related disorders.

Economic analyses of geriatric syndromes are seldom performed. However, demographic and epidemiological imperatives have led to significant interest in the evaluation of AD-related costs. Over 300 papers devoted to economic considerations of Alzheimer's disease have been published in peer-reviewed journals, within the last five years. In these papers, the chosen perspective (costs to society or to specific payers) is important. Analytical methods are still evolving and remain complex. Unresolved methodological issues will need to be addressed to further our understanding of long-term economic consequences. At present, it is clear that diagnostic and drug costs are low compared to the major cost of institutionalization. Thus, directing efforts at early diagnosis and delaying nursing home placement are two key cost-containment interventions. In this respect, the need to support informal care should not be underestimated.

Aged↗
PubMed2001

Brain energy metabolism in Alzheimer's disease: 99mTc-HMPAO SPECT imaging during verbal fluency and role of astrocytes in the cellular mechanism of 99mTc-HMPAO retention.

The central hypothesis of the study which has been carried out as part of the NRP38 program, is that perturbations of brain energy metabolism are critically involved in the neurodegeneration occurring in Alzheimer's disease (AD) and that they may correlate with early cognitive dysfunctioning. In the present multidisciplinary study we set out to monitor brain energy metabolism using FDG-PET and HMPAO-SPECT imaging in a cohort of individuals over 65 years of age, drawn from the general population. HMPAO-SPECT imaging, which is a simpler and more widely accessible imaging procedure than FDG-PET, was performed under basal conditions and during the performance of a cognitive task (verbal fluency test). Three groups were studied. Two groups (groups I and II) included individuals age 65 or more, with no cognitive impairment and carrying an APOE4 positive or APOE4 negative phenotype, respectively; a third group (group III) included patients with clinical signs of AD. Each subject entering the study underwent an FDG-PET, an HMPAO-SPECT and an extensive battery of neuropsychological tests which assess various aspects of cognitive functioning, with a strong emphasis on working memory, divided attention and executive functions. A total of 101 participants were submitted to brain imaging and neuropsychological testing. Among these, 60 participants received the same set of imaging and neuropsychological tasks 24-36 months after the first set (phase II). In this article, we present a preliminary analysis performed on ten subjects from groups I and II and nine subjects from group III: activation (verbal fluency task) induced a specific pattern of increase in HMPAO retention (including BA 9/10, BA 18 bilaterally and right BA 17). In contrast to controls, in nine AD subjects no significant differences in HMPAO retention were observed when comparing activation and basal conditions. The cellular and molecular mechanisms that underlie the retention of HMPAO, the tracer used for single photon emission computed tomography (SPECT) imaging, has been studied in vitro in purified preparations of neurons and astrocytes with the aim of investigating the contribution of different cell types to hexamethyl-propyleneamineoxime labeled with technetium-99m (99mTc-HMPAO) retention in vitro. Results show that 99mTc-HMPAO retention predominates in astrocytes over neurons by a factor of approximately 2.5. Diethyl maleate, ethacrynic acid and buthionine sulfoximine, three agents which significantly reduce glutathione levels, also decreased 99mTc-HMPAO retention in both astrocytes and in neurons. Decrease did not always correlate with glutathione levels however, thus suggesting that other factors could be involved. The data presented indicate that astrocytes might constitute a prominent site of 99mTc-HMPAO retention and most likely contribute significantly to the SPECT signal. In addition, they also suggest that specific alterations in glial cell metabolism could explain flow-independent changes in 99mTc-HMPAO retention in the brain as observed by SPECT in certain pathologies (including Alzheimer's disease). In particular, these observations suggest a key role of astrocytes in the signal detected with the imaging procedure, which is altered in the Alzheimer's cohort subjected to the verbal fluency activation task.

Aged↗
PubMed2001

Cause of death in older patients with anatomo-pathological evidence of chronic bronchitis or emphysema: a case-control study based on autopsy findings.

OBJECTIVES: To determine the most frequent causes of death of hospitalized older patients based on anatomo-pathological evidence and to compare the relative frequency of fatal events between patients with and without evidence of either chronic bronchitis (CB) or emphysema (E). DESIGN: Retrospective, case-control study based on a computerized database including anatomo-pathological data of patients deceased and autopsied over a 25-year period. SETTING: Two geriatric hospitals in Geneva. PARTICIPANTS: Not applicable. MEASUREMENTS: Autopsy records for cause(s) of death in patients with CB or E. RESULTS: 3,685 patients deceased in our institution (1,540 men; 2,145 women) were autopsied between 1972 and 1996; mean age at death was 81.5 +/- 8.0 years. Anatomo-pathological evidence of CB or E was found in 983 patients (26.6% of total); 262 (7.2%) had predominantly CB, and 456 (12.3%) predominantly E. Pneumonia was the most frequent cause of death in all patients (21.8%). Myocardial infarction (MI) (17.6% vs 14%), and respiratory failure (5.1% vs 1.5%) occurred more frequently in subjects with CB and/or E than in controls. Fatal pulmonary embolism (PE) was more frequent in patients with E (18.4%) than in patients with CB (10.7%; odds ratio ( OR) = 1.89, P =.008), or in controls (12.7%; OR = 1.56, P =.0008). CONCLUSION: Anatomo-pathological evidence of CB or E is highly prevalent in older patients, suggesting that CB and E are clinically underdiagnosed in this age group. Fatal MI occurred significantly more frequently in older patients with E or CB than in controls. Furthermore, patients with E were at significantly higher risk of fatal PE than patients with CB or controls.

Age Distribution↗
PubMed2001

Total body mass, fat mass, fat-free mass, and skeletal muscle in older people: cross-sectional differences in 60-year-old persons.

OBJECTIVES: To evaluate body composition parameters, including fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), relative skeletal muscle mass (RSM) index, body cell mass (BCM), BCM index, total body potassium (TBK), fat mass, percentage fat mass (FM), and their differences between age groups and to evaluate the frequency of sarcopenia in healthy older subjects DESIGN: Cross-sectional, nonrandomized study. SETTING: Outpatient clinic. PARTICIPANTS: Ninety-one healthy men and 100 healthy women age 60 and older. MEASUREMENTS: FFM, ASMM, FM, and percentage fat mass by whole-body dual-energy x-ray absorptiometry; TBK, BCM, and TBK/FFM ratio by whole body potassium-40 counter. RESULTS: All lean body mass parameters were significantly (P <.05) lower in subjects age 80 and older than in those age 70 to 79, except ASMM in women. Mean FFM was 4.2 kg (7.3%) lower in men age 80 and older than in those younger than 70 and 2.9 kg (6.8%) lower in women age 80 and older than in those younger than 70. The skeletal muscle mass, reflected by ASMM, decreased more than FFM. This suggests that nonskeletal muscle mass is proportionally preserved during aging. Forty-five percent of men and 30% of women were sarcopenic by definition of BCM index and 11.0% of men and women by definition of RSM index. CONCLUSIONS: Significant age-related differences exist in body composition of older men and women between age 60 and 95. The greater decrease in TBK and BCM than the decrease in FFM and skeletal muscle mass suggests changing composition of FFM with age. Lack of agreement between two independent sarcopenia indexes suggests that further refinement in the definition of a sarcopenia index is necessary.

Absorptiometry, Photon↗
PubMed2001

Diagostic value of respiratory impedance measurements in elderly subjects.

Obstructive lung disease (OLD) is highly prevalent in elderly subjects but markedly under-diagnosed. Indeed, only 40-50% of hospitalized elderly patients are able to adequately perform spirometric tests. This study aimed to evaluate, in an acute-care geriatric hospital, the diagnostic value of measuring airway impedance (Zrs) by the forced oscillation technique (FOT) for: (1) identifying OLD and (2) identifying responders vs. non-responders to bronchodilators. Sixty-seven patients (aged 82+/-8 years) underwent consecutive measurement of Zrs and forced expiratory volumes before and after bronchodilators. Zrs was measured by FOT at frequencies of 4-30 Hz. Correlations, ROC curves and logistic regression models were established to determine the sensitivity (Se) and specificity (Sp) of Zrs in identifying OLD. Significant correlations were found between spirometric and Zrs measurements. The Zrs parameters yielding the best Se and Sp for detecting OLD were: Fn (resonant frequency; Se: 76%; Sp: 78%) and R0 (resistance extrapolated for a frequency of 0: Se: 76%; Sp: 74%). Using the logistic regression models, 76% of the patients were correctly classified as having OLD or not. Zrs was however not contributive in identifying responders to bronchodilators. Zrs measurements by FOT are contributive to the diagnosis of OLD in elderly hospitalized patients.

Aged↗
PubMed2001

Does the mini nutritional assessment predict hospitalization outcomes in older people?

BACKGROUND: the Mini Nutritional Assessment is a validated clinical tool for the assessment of nutritional status in older people. Moderate to severe malnutrition is common in elderly patients in hospital and is associated with a poor outcome. OBJECTIVES: to determine whether the Mini Nutritional Assessment can predict the outcome of hospital stay in older individuals. SETTING: a tertiary-care geriatric hospital. METHODS: we evaluated nutritional status using the Mini Nutritional Assessment in 1319 patients (mean age 84.2, 70% women) admitted between February 1996 and January 1998; 1145 complete assessments were available for analysis. The assessment was carried out on admission and studied in relation to length of stay and in-hospital mortality for all patients, and discharge to a nursing home for those living at home before admission. RESULTS: Mini Nutritional Assessment scores averaged 19.9+/-3.8 (mean+/-SD) with a range of 8.0-27.5, and a median of 20.5. A score below 17, corresponding to malnutrition, was associated with an almost threefold increase in mortality and in the rate of discharge to a nursing home; this contrasted with a score above 24, which indicates satisfactory nutritional status (11.3% vs 3.7%; P<0.01 and 20.3% vs 7.7%; P<0.001, respectively). Length of stay was longer in the low scoring group (42.0 days vs 30.5 days; P<0.0002). CONCLUSION: Poor nutritional status as measured by the Mini Nutritional Assessment was associated with increased in-hospital mortality, a higher rate of discharge to nursing homes and a longer length of stay.

Activities of Daily Living↗
PubMed2001

[Acute community acquired pneumopathy caused by Nocardia asteroides in a 93-year-old female patient].

BACKGROUND: Lower respiratory tract infection (LRTI) by Nocardia species is most often considered as an opportunistic infection occurring mainly in middle-aged adults. CASE REPORT: A 93-year old woman without any significant comorbidity other than a mild asthma, presenting with a non-resolving pneumonia, was successfully treated for a community-acquired LRTI by Nocardia asteroides. DISCUSSION: LRTI by Nocardia asteroides is a rare occurrence. Although more frequent in immuno-compromised patients (50 to 85% of cases reported), Nocardia asteroides infection also occurs in immuno-competent individuals. Very few reports describe LRTI infection by Nocardia sp. in the very old, and almost exclusively in patients with major co-morbidities or variable degrees of immuno-suppression.

Acute Disease↗
PubMed2000

[Collaboration between the geriatrician and the surgeon: a major contribution for the aged patient in rehabilitation].

BACKGROUND: Subtrochanteric fractures are complex fractures requiring prudent reeducation. In elderly patients who also have other illnesses, reeducation of walking may be quite difficult. CASE REPORT: An 89-year-old woman was referred for physical therapy after osteosynthesis of a comminutive subtrochanteric fracture. Weight bearing was contraindicated for 3 months due to her "incapacity to perform reeducation exercises". The patient also had several serious co-morbidities which had to be integrated into the reeducation program. DISCUSSION: In cases of complex fractures, reeducation must take into account other comorbid conditions. Outcome can be favorable, but requires a well organized interdisciplinary approach associating the geriatrics and the orthopedics teams.

Aged↗
PubMed2000

Sleep disordered breathing in the elderly.

Sleep disordered breathing (SDB), i.e., obstructive, central or mixed sleep apneas, has been recognized as a common occurrence in the elderly. Aging is per se associated with a decrease in the quality of sleep; SDB may further disrupt the sleep architecture in older subjects. The prevalence of obstructive sleep apnea (OSA) increases with aging; available studies report prevalence rates of 11-62%. Furthermore, OSA has been associated with increased mortality in older adults. Central apneas and periodic breathing occur with increased frequency either in subjects with neurological disorders such as infarction, tumor, sequelae of infection, diffuse encephalopathies, or in chronic heart failure. Patients with cerebrovascular disease (stroke, or transient ischemic attacks) have a markedly high prevalence of SDB, mainly OSA. In these patients, SDB is associated with a poorer functional prognosis at 3 and 12 months after the acute event, and a higher mortality. The clinical impact of SDB on cognitive function appears to be modest in patients without dementia, although there is a moderate increase in daytime sleepiness. In Alzheimer's disease (AD) however, SDB occurs more frequently than in non-demented older subjects, and its severity is correlated with the degree of cognitive impairment. The hypothesis of a causal relationship between AD and SDB remains a subject of controversy. The possibility of SDB should be considered in the elderly in the differential diagnosis of "reversible dementias", increased daytime sleepiness, or unexplained right-sided heart failure.

Aged↗
PubMed2000

Clinical validity of Braak neuropathological staging in the oldest-old.

Several studies have demonstrated a good correlation between clinical severity and Braak's neuropathological staging in Alzheimer's disease (AD). However, nonagenarians and centenarians display a different pattern of cortical vulnerability to the neurodegenerative process compared to younger elderly, and it is not known whether correlations between clinical severity and neuropathological stages remain valid in this age group. To address this issue we compared Clinical Dementia Rating scale (CDR) scores and Braak stages in 116 patients over 90 years of age with either no cognitive impairment or very mild to severe AD. There is a strong positive correlation between CDR scores and Braak staging (Spearman coefficient = 0.66; P < 0.01). However, neuropathological staging does not distinguish cases with normal cognition (CDR 0) from those with mild cognitive changes (CDR 0.5). Unlike younger cohorts, Braak stages I and II are frequently associated with questionable dementia in this age group. Braak stage III overlaps with all CDR levels and correlates poorly with cognitive function. Braak stages IV or greater are consistently associated with at least mild dementia. Consistent with our previous neuropathological analyses of nonagenarians and centenarians, the present data suggest that the substantial involvement of the hippocampus which characterizes Braak stage IV is a key step in the development of overt clinical signs of dementia in the oldest-old. Moreover, they indicate that Braak staging represents a broad concept of the evolution of neurofibrillary tangles rather than a precise hierarchical model associated with a stepwise deterioration of cognitive abilities near the upper limit of life.

Aged↗
PubMed2000

Neural substrates of spatial and temporal disorientation in Alzheimer's disease.

To examine the neuroanatomical correlates of spatial and temporal disorientation in Alzheimer's disease (AD), we performed an anterograde clinicopathological study of 29 patients with clinically and neuropathologically confirmed AD. Spatial and temporal disorientation was assessed using the locational orientation subtests of the Mini Mental State Examination and the Benton's test for temporal orientation. Quantitative analysis of neurofibrillary tangles and senile plaques were performed in the CA1 field of the hippocampus, layers II and V of the entorhinal cortex, and layers II-III and V-VI of areas 9, 7, 39, 19, 37, 20 and 23 in the right hemisphere. Forward stepwise logistic regression was used to assess the relationship between lesion densities and the presence of either spatial or temporal disorientation; severity scores and brain weight were included as covariants. A statistically significant relationship was found between neurofibrillary tangle densities in Brodmann's areas 7, 23 and the CA1 field of hippocampus and both spatial and temporal disorientation. Senile plaque counts did not correlate with any of the neuropsychological parameters. Both temporal and spatial disorientation in AD are related to the degeneration of the same pathways linking the hippocampus with the superior parietal and posterior cingulate cortex in the right hemisphere. These observations are discussed with respect to the notion of global corticocortical disconnection in AD.

Aged↗