Reconstruction of the history of anthropogenic CO(2) concentrations in the ocean.

The release of fossil fuel CO(2) to the atmosphere by human activity has been implicated as the predominant cause of recent global climate change. The ocean plays a crucial role in mitigating the effects of this perturbation to the climate system, sequestering 20 to 35 per cent of anthropogenic CO(2) emissions. Although much progress has been made in recent years in understanding and quantifying this sink, considerable uncertainties remain as to the distribution of anthropogenic CO(2) in the ocean, its rate of uptake over the industrial era, and the relative roles of the ocean and terrestrial biosphere in anthropogenic CO(2) sequestration. Here we address these questions by presenting an observationally based reconstruction of the spatially resolved, time-dependent history of anthropogenic carbon in the ocean over the industrial era. Our approach is based on the recognition that the transport of tracers in the ocean can be described by a Green's function, which we estimate from tracer data using a maximum entropy deconvolution technique. Our results indicate that ocean uptake of anthropogenic CO(2) has increased sharply since the 1950s, with a small decline in the rate of increase in the last few decades. We estimate the inventory and uptake rate of anthropogenic CO(2) in 2008 at 140 +/- 25 Pg C and 2.3 +/- 0.6 Pg C yr(-1), respectively. We find that the Southern Ocean is the primary conduit by which this CO(2) enters the ocean (contributing over 40 per cent of the anthropogenic CO(2) inventory in the ocean in 2008). Our results also suggest that the terrestrial biosphere was a source of CO(2) until the 1940s, subsequently turning into a sink. Taken over the entire industrial period, and accounting for uncertainties, we estimate that the terrestrial biosphere has been anywhere from neutral to a net source of CO(2), contributing up to half as much CO(2) as has been taken up by the ocean over the same period.

Radiocarbon constraints on the glacial ocean circulation and its impact on atmospheric CO2.

While the ocean's large-scale overturning circulation is thought to have been significantly different under the climatic conditions of the Last Glacial Maximum (LGM), the exact nature of the glacial circulation and its implications for global carbon cycling continue to be debated. Here we use a global array of ocean-atmosphere radiocarbon disequilibrium estimates to demonstrate a ∼689±53 14C-yr increase in the average residence time of carbon in the deep ocean at the LGM. A predominantly southern-sourced abyssal overturning limb that was more isolated from its shallower northern counterparts is interpreted to have extended from the Southern Ocean, producing a widespread radiocarbon age maximum at mid-depths and depriving the deep ocean of a fast escape route for accumulating respired carbon. While the exact magnitude of the resulting carbon cycle impacts remains to be confirmed, the radiocarbon data suggest an increase in the efficiency of the biological carbon pump that could have accounted for as much as half of the glacial-interglacial CO2 change.

Use of medications with anticholinergic effect predicts clinical severity of delirium symptoms in older medical inpatients.

BACKGROUND: Use of anticholinergic (ACH) medications is a biologically plausible and potentially modifiable risk factor of delirium, but research findings are conflicting regarding its association with delirium. OBJECTIVES: To evaluate the longitudinal association between use of ACH medications and severity of delirium symptoms and to determine whether this association is modified by the presence of dementia. PATIENTS AND METHODS: A total of 278 medical inpatients 65 years and older with diagnosed incident or prevalent delirium were followed up with repeated assessments using the Delirium Index for up to 3 weeks. Exposure to ACH and other medications was measured daily. The association between change in medication exposure in the 24 hours preceding a Delirium Index assessment was assessed using a mixed linear regression model. RESULTS: During follow-up (mean +/- SD, 12.3 +/- 7.0 days), 47 medications with potential ACH effect were used in the population (mean, 1.4 medications per patient per day). Increase in delirium severity was significantly associated with several measures of ACH medication exposure on the previous day, adjusting for dementia, baseline delirium severity, length of follow-up, and number of non-ACH medications taken. Dementia did not modify the association between ACH medication use and delirium severity. CONCLUSION: Exposure to ACH medications is independently and specifically associated with a subsequent increase in delirium symptom severity in elderly medical inpatients with diagnosed delirium.

Comparative ethics and geriatric psychiatry: looking at motivations.

In the broadest sense, medicine is a biologic-anthropologic model. The latest data on epidemiology and biology confirm earlier apprehensions about life expectancy, number of elderly, and the impact of mental impairment. The author wishes to reflect rather on anthropology by comparing the American and French cultures faced with the ethical dilemmas of aging and end-of-life issues. On this perilous frontier of biomedical ethics, the author suggests that the right to be treated as a person is an effective source of motivation for physicians to respect the dignity of geriatric patients in the context of high-technology medicine.

Chronic subdural hematoma in the elderly: a case report.

A previously healthy 82-year-old male presented with depressive and paranoid symptoms of 3 months' duration. Physical examination and cognitive functions were normal. Poor response to treatment and continuing weight loss lead to medical investigations that ultimately showed a large, left frontoparietal, chronic subdural hematoma. Following drainage, the patient showed some improvement in paranoid features but still required pharmacologic treatment for depression. The psychiatric features of chronic subdural hematoma as well as the management of this neurologic condition in the elderly patient are reviewed and discussed.

Delirium: prevention, treatment, and outcome studies.

The purpose of this paper was to contribute to a new conceptual understanding of delirium by reviewing evidence related to its prevention, treatment, and outcome. The review process involved a systematic search of the literature on each topic, assessment of the validity of the studies retrieved, and examination of their results. The literature search identified 10 studies on prevention, 13 studies on treatment, and 15 studies on outcome. Most studies had methodological limitations. Abroad spectrum of interventions appeared to be modestly effective in preventing delirium in young and old surgical patients but not elderly medical patients; systematic detection and intervention programs and special nursing care appeared to add large benefits to traditional medical care in young and old surgical patients and modest benefits in elderly medical patients; haloperidol, chlorpromazine, and mianserin appeared to be useful in controlling the symptoms of delirium in both surgical and medical patients; and good levels of premorbid function seemed to be related to better outcomes. Although the above findings do not contribute to a new conceptual understanding of delirium, they do suggest directions for further research on the treatment of delirium.

[Multiple intracranial aneurysms associated with primary hyperaldosteronism]. / Anévrysmes intracrâniens multiples associés à un hyperaldostéronisme primaire.

Multiple intracranial aneurysms have been reported in association with polycystic disease of the kidney, brain tumor, pituitary adenoma and coarctation of the aorta. We report the association of multiple aneurysms with primary hyperaldosteronism due to bilateral adrenal hyperplasia in an 18 year old left-handed man who presented with subarachnoid hemorrhage and arterial hypertension. We report the excellent outcome of this patient in spite of a difficult and surgical management. Ligation of all three intracranial aneurysms was performed after an extra-intracranial arterial bypass was done as a protective measure.

[Psychogeriatrics in the year 2000: a medical and ethical challenge for society in Quebec]. / La psychogériatrie des années 2000: un défi médical et éthique pour la société québécoise.

During the past fifteen years, remarkable developments have occurred in Psychogeriatrics. Major advances have taken place in the biology of aging and the care of the elderly. Because of the demographic expansion of the geriatric population, psychiatrists and family physicians need to be familiar with the specific interventions which are available to tract the psychiatric problems of the elderly. Economic concerns should not distract attention from fundamental ethics issues connected with Psychogeriatrics. The intrinsic dignity of every human being must be recognized especially in the case of more vulnerable elderly patients. Such a conviction could prove essential as medicine and ethics face the new challenges that Psychogeriatrics will bring to Quebec int the next decades.

Post-stroke depression: a critical review of the literature.

Because of its physical, psychological, interpersonal and financial repercussions, post-stroke depression is a sensitive issue facing patients, clinicians and society as a whole. The author highlights some difficulties with respect to research methodology, definition, etiology and treatment as reported in the recent scientific literature. Although this review challenges some notions about etiology and rates of post-stroke depression, suggestions are outlined to help prevent, recognize and treat this disorder, the incidence of which is expected to increase because of the demographic trend of our population towards aging.

Complex visual hallucinations in macular degeneration.

A previously healthy elderly patient with a recent onset of macular degeneration presented for evaluation of elaborate complex visual hallucinations. The patient's psychiatric evaluation and level of cognitive functioning were normal. A diagnosis of organic hallucinosis secondary to macular degeneration was made, and the hallucinations ceased with increased sensory stimulation in the hospital. Numerous diagnoses were considered and are discussed, including Charles Bonnet hallucinations and peduncular hallucinosis.

Obsessive disorder with self-mutilation: a subgroup responsive to pharmacotherapy.

Obsessive-compulsive disorder (OCD) can be considered a complex entity with possibly different subgroups responsive to specific treatment. This article presents two cases of OCD with self-mutilation, successfully treated with serotonergic antidepressants. The authors discuss a sub-group of OCD patients whose rituals present as self-destructive behavior and are responsive to pharmacotherapy.

Prognosis of delirium in elderly hospital patients.

OBJECTIVE: To determine the prognosis of delirium in elderly patients. DATA SOURCES: MEDLINE was searched for relevant articles published from January 1980 to March 1992. The bibliographies of identified articles were searched for additional references. STUDY SELECTION: Eight reports (involving 573 patients with delirium) met the following inclusion criteria: original research, published in English or French, prospective study design, diagnosis based on acute deterioration in mental state, sample of at least 20 patients, patients aged 60 years or over and follow-up of at least 1 week. The validity of the studies was independently assessed according to the criteria for prognostic studies established by McMaster University, Hamilton, Ont. No study met all the criteria. DATA EXTRACTION: Information about the patient sample, length of follow-up and results was systematically abstracted from each report and tabulated. DATA SYNTHESIS: A meta-analysis of the outcomes indicated that elderly patients with delirium had a mean length of stay of 20.7 days. One month after admission 46.5% were in institutions, and 14.2% had died; only 54.9% had improved mentally. Six months after admission 43.2% were in institutions. Compared with unmatched control subjects they had longer hospital stays, higher mortality rates at 1 month and higher rates of institutional care at 1 and 6 months. The presence of severe physical illness or dementia may have been related to some outcomes. CONCLUSIONS: Delirium in the elderly appears to have a poor prognosis. However, this finding may have been confounded by the presence of concomitant dementia or severe physical illness. Future studies must pay attention to methods and design, particularly the composition of study populations and the control of extraneous prognostic factors.

Valproic acid and panic disorder.

Valproic acid (VA), an anticonvulsant which increases GABAergic transmission was given to patients suffering from recurrent panic attacks. Ten consecutive outpatients were included in this study. After a seven day placebo washout period, patients were given a dose of 500 mg/day, which was gradually increased to a maximum of 2250 mg/day. A significant improvement was found in the symptomatology of patients as measured on the Clinical Global Impression Scale for panic severity (p less than 0.001), the Hamilton Psychiatric Rating Scale for Anxiety (p less than 0.001) and the panic factor of the SCL-90 (p less than 0.05). These findings support the hypothesis that VA is useful in the treatment of panic disorders. Further research should be carried out to assess its efficacy and safety.

Effectiveness of interventions to prevent delirium in hospitalized patients: a systematic review.

OBJECTIVE: To determine the effectiveness of interventions to prevent delirium in hospitalized patients. DATA SOURCES: Two databases, MEDLINE and CINAHL, were searched for relevant articles published from January 1966 to May 1995 and from January 1982 to May 1995 respectively. The bibliographies of identified articles were searched for additional references. STUDY SELECTION: Ten articles met the following three inclusion criteria: (a) original research article, (b) published in English or French and (c) controlled trial (nonrandomized or randomized) of an intervention to prevent delirium in hospitalized patients. The validity of the studies was independently assessed according to the criteria for intervention studies proposed by the Evidence-Based medicine Working Group. DATA EXTRACTION: Information about study design, patient population, sample size, diagnostic criteria, interventions and results was systematically abstracted from each report. Absolute risk reduction (ARR) for delirium was calculated for each study. DATA SYNTHESIS: Eight trials involved surgical patients and two involved elderly medical patients; most of the studies had serious methodological limitations. Among the surgical patients the ARRs ranged from -13% to 81% and were not related to the type or timing of the intervention, or to the personnel involved. Among the elderly medical patients the ARRs ranged from -3% to 3%. CONCLUSION: Interventions to prevent delirium among surgical patients may be modestly effective, but further trials are necessary.

Reliability and validity of a new measure of severity of delirium.

The objective of this study was to assess the psychometric properties of a new instrument, the Delirium Index (DI), to measure changes in the severity of the symptoms of delirium among patients previously diagnosed with delirium. Subjects were medical inpatients aged 65 and over diagnosed with delirium by the Confusion Assessment Method. Interrater reliability of the DI was .78 between research assistants (concordance coefficient) and was .88 between research assistants and geriatric psychiatrists. Criterion validity, assessed by the correlation between DI and Delirium Rating Scale scores (Spearman's correlation coefficient, r), was .84. Construct validity was assessed using correlations of the DI with two measures of current function for convergent validity (r = -.60, -.70) and two measures of function before admission for discriminant validity (r = .26,-.42). We conclude that the DI has acceptable levels of interrater reliability, criterion validity, and construct validity.

Clinical case discussion: the elderly patient with psychosis.

OBJECTIVE: To present a clinical case of an elderly person with psychosis and to discuss associated diagnostic and treatment issues. METHODS: A case from 1 of the authors' clinical practices was presented in English and French to several groups of Canadian psychiatrists attending a teaching day on psychosis. Three geriatric psychiatrists acted as facilitators, soliciting the clinical experiences of the participants in the discussion. The authors integrated clinical content from these sessions with results of a Medline search on psychosis in elderly persons. RESULTS: The assessment of elderly patients with psychosis is more often than in younger patients by overlying organicity, including delirium due to illness or medication use, dementia, or sensory deficits. Treatment might further worsen cognitive, affective, and functional impairment through adverse effects such as extrapyramidal symptoms (leading to decreased mobility and general functioning), anticholinergic effects (predisposing to delirium), and hypotension (predisposing to falls). Newer antipsychotics with less hazardous side effect profiles have an increasing role, but they must be coupled with psychosocial support to maximize the patient's independent functioning and quality of life after discharge. CONCLUSIONS: Assessment and treatment of the elderly person with psychosis must consider a wide variety of biopsychosocial variables, seeking to minimize further treatment-related deterioration. Controlled studies of antipsychotics in elderly people must be conducted in a variety of diagnostic situations that reflect their actual use in the community, and information must be propagated effectively among general psychiatrists, family physicians, and geriatric psychiatrists. The role of nonpharmacologic interventions in elderly persons with psychosis is even less well understood and deservers further study.

Psychosocial risk factors in poststroke depression: a systematic review.

OBJECTIVE: To review systematically the psychosocial risk factors for poststroke depression. METHODS: Medline was searched using the key words "poststroke depression" (PSD) for the period January 1, 1966, to June 30, 2000; using the key words "cerebrovascular disease" and "depression" it was searched from June 1, 1996, to June 30, 2000. Corollary articles were obtained from the bibliographies. Inclusion criteria were as follows: original research in French or English; prospective, case-control or cross-sectional study design; assessment of PSD in the first 6 months following the stroke; an acceptable definition of depression; an acceptable definition of stroke; and at least one psychosocial risk factor. Interrater reliability was tested for the selection and quality of the articles. A qualitative risk factor analysis was conducted. RESULTS: The risk factors most consistently associated with PSD are a past history of depression, past personal psychiatric history, dysphasia, functional impairments, living alone, and poststroke social isolation. Risk factors not associated with PSD are dementia and cognitive impairment. Controversial risk factors are age, socioeconomic status (SES), prior social distress, dependency in regard to activities of daily living (ADL), and sex. CONCLUSIONS: Over approximately 30 years, some 25 qualitative studies have addressed psychosocial risk factors for PSD. Further studies should aim for quantitative analysis. The results suggest that identifying psychiatric history and preventing social deterioration and impairment should be part of multidisciplinary efforts to care for poststroke patients.

Tracking cognitive decline in Alzheimer's disease using the mini-mental state examination: a meta-analysis.

OBJECTIVES: To estimate the annual rate of change scores (ARC) on the Mini-Mental State Examination (MMSE) in Alzheimer's disease (AD) and to identify study or population characteristics that may affect the ARC estimation. METHODS: MEDLINE was searched for articles published from January 1981 to November 1997 using the following keywords: AD and longitudinal study or prognosis or cognitive decline. The bibliographies of review articles and relevant papers were searched for additional references. All retrieved articles were screened to meet the following inclusion criteria: (a) original study; (b) addressed cognitive decline or prognosis or course of AD; (c) published in English; (d) study population included AD patients with ascertainable sample size; (e) used either clinical or pathological diagnostic criteria; (f) longitudinal study design; and (g) used the MMSE as one of the outcome measures. Data were systematically abstracted from the included studies, and a random effects regression model was employed to synthesize relevant data across studies and to evaluate the effects of study methodology on ARC estimation and its effect size. RESULTS: Of the 439 studies screened, 43 met all the inclusion criteria. After 6 studies with inadequate or overlapping data were excluded, 37 studies involving 3,492 AD patients followed over an average of 2 years were included in the meta-analysis. The pooled estimate of ARC was 3.3 (95% confidence interval [CI]: 2.9-3.7). The observed variability in ARC across studies could not be explained with the covariates we studied, whereas part of the variability in the effect size of ARC could be explained by the minimum MMSE score at entry and number of assessments. CONCLUSIONS: A pooled average estimate of ARC in AD patients was 3.3 points (95% CI: 2.9-3.7) on the MMSE. Significant heterogeneity of ARC estimates existed across the studies and cannot be explained by the study or population characteristics investigated. Effect size of ARC was related to the initial MMSE score of the study population and the number of assessments.

Summer and winter patterns of seasonality in Chinese college students: a replication.

The goal of this study is to replicate an earlier epidemiological finding of seasonal changes in mood and behavior among Chinese medical students using an independent study population. Three hundred nineteen college students were surveyed with a Chinese version of the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Beck Depression Inventory (BDI) in Jining, China, during March of 1996. The frequency of seasonal patterns and prevalence rates of seasonal affective disorder (SAD) were estimated and compared with data from the medical student survey conducted in the same city. The mean Global Seasonality Score (GSS) of this college student sample was 9.9 +/- 4.9; 84% of the subjects reported some problems with the changing seasons. Summer difficulties were more prevalent than winter difficulties by a ratio of 1.9 to 1 (38.9% v 20.1%). The estimated rates of summer SAD and subsyndromal-SAD (s-SAD) were 7.5% and 11.9%, respectively, as compared with the corresponding winter figures of 5.6% and 6.3%. In addition, the prevalence estimates of winter pattern or winter SADs were higher in males than in females, but the corresponding summer figures showed no gender difference. Compared with the data from the medical student survey, this college student sample had a higher GSS (P < .01) but comparable summer to winter and female to male ratios for the prevalence of SADs (P > .05). These results replicate our previous findings that seasonal problems are common in China, but the predominant problems are summer difficulties rather than winter difficulties, and there is no female preponderance in the prevalence estimates of such problems. Both findings stand in contrast to most Western studies but are consistent with the only other published study performed in the Orient.