Hippocampal volume measurement in older adults with bipolar disorder.

OBJECTIVE: Decreased hippocampal volumes have been noted in unipolar depressed subjects, especially in elderly patients and those with cognitive impairment. Initial studies of mixed-aged bipolar subjects and controls have had conflicting findings, with most noting no difference; however this region has not been examined in older bipolar subjects. METHODS: The authors examined the hippocampal volumes of 36 older bipolar subjects (mean age: 58 years) and 29 older normal-comparison (NC) subjects (mean age: 61), using logistic-regression analyses to control for age and gender. Differences between late- and early-onset (before age 45) bipolar subjects were also examined. RESULTS: The left hippocampus was noted to be enlarged in older bipolar subjects, compared with the older NC group (sex and age controlled). No differences were noted in hippocampal volumes by age at onset nor number of previous episodes. The increase in hippocampal volume may be associated with the use of lithium, but not valproic acid. CONCLUSIONS: Left-hippocampal volume is increased in older bipolar subjects compared with NC subjects. The differences were not explained by age at onset, current mood state, or cognitive status, but may be associated with exposure to lithium. This finding would support previous observations about the neural-plasticity effect of lithium.     

Medical comorbidity in a bipolar outpatient clinical population.

The presence of medical illnesses among inpatients with bipolar disorder is known to complicate treatment and lengthen hospital stay. However, except for a few specific diseases, little is known about prevalence of medical illnesses in bipolar outpatients and the effect it may have on treatment. The authors sought to assess the presence of medical illnesses in a large outpatient clinical sample of bipolar patients, and the effect that medical illnesses may have on the clinical assessment and treatment of the underlying bipolar disorder. Using the Duke University Medical Center clinical database, the authors categorized the medical diagnoses of 1379 patients who were treated with bipolar disorder from 2001 to 2002 through outpatient psychiatric clinics. The prevalence of medical comorbidities was examined, as well as the effect their presence had on the clinician's assessment of disease severity and time to improvement. As expected, medical comorbidities increased with age. The most common systemic illnesses in bipolar outpatients were Endocrine and Metabolic Diseases (13.6% of the sample), Diseases of the Circulatory System (13.0%), and Diseases of the Nervous System and Sense Organs (10.7%). Significant specific diseases included cardiovascular diseases/hypertension (10.7%), COPD/asthma (6.1%), diabetes (4.3%), HIV infection (2.8%), and hepatitis C infection (1.9%). Clinicians assessed greater severity of illness in patients with increasing numbers of comorbid conditions; however, the time to recovery was not significantly effected by the presence of medical comorbidity. In conclusion, comorbid medical illnesses are common in bipolar outpatients, increasing with age. HIV rates may be increased relative to population norms. Their presence compounds the severity of the illness at time of presentation.     

The relation of free plasma tryptophan to anger, hostility, and aggression in a nonpatient sample of adult men and women

Background: Dysregulation of central nervous system serotonergic (5-HT) activity is implicated in behavioral states and psychological traits associated with depression and aggression, with some studies suggesting possible gender-related differences.Purpose: This study examined the relation of free plasma tryptophan (TRP) to aggression and depression in a sample of 138 nonsmoking adults recruited from the general community. It was hypothesized that TRP would be associated with anger, hostility, and aggression.Methods: To minimize effects of diurnal variation and menstrual cycle, fasting blood samples were collected in the morning, and, for women, during the follicular phase of the menstrual cycle. Participants were administered questionnaires following blood draw. Plasma TRP was determined by high performance liquid chromatography.Results: In women, but not men, higher levels of TRP were associated with trait hostility, propensity for anger, a tendency to express anger outwardly, and an antagonistic interpersonal style. For men and women, greater severity of depressive symptoms, anger, and the verbal expression of anger were associated with higher TRP. These associations were independent of age, body mass index, fasting albumin, and race and ethnicity.Conclusions: These data suggest that in women, but not men, higher plasma levels of TRP, the precursor to 5-HT, are associated with anger-hostility-aggression and that these associations are independent of various potential confounds. Implications of these observations to studies employing acute TRP depletion studies are discussed. This study was supported by grant HL56105 and HL67459 to the first author. The authors wish to thank Wilma Young, Donetta Miller, Andrew Wieman, Audra de Ridder and Donna Biracree for their assistance in data collection. We also thank Stephen Boyle, PhD for his comments and suggestions on previous drafts of this article.     

Variations in atmospheric CO2 growth rates coupled with tropical temperature

Previous studies have highlighted the occurrence and intensity of El Niño–Southern Oscillation as important drivers of the interannual variability of the atmospheric CO₂ growth rate, but the underlying biogeophysical mechanisms governing such connections remain unclear. Here we show a strong and persistent coupling (r² ≈ 0.50) between interannual variations of the CO₂ growth rate and tropical land–surface air temperature during 1959 to 2011, with a 1 °C tropical temperature anomaly leading to a 3.5 ± 0.6 Petagrams of carbon per year (PgC/y) CO₂ growth-rate anomaly on average. Analysis of simulation results from Dynamic Global Vegetation Models suggests that this temperature–CO₂ coupling is contributed mainly by the additive responses of heterotrophic respiration (Rh) and net primary production (NPP) to temperature variations in tropical ecosystems. However, we find a weaker and less consistent (r² ≈ 0.25) interannual coupling between CO₂ growth rate and tropical land precipitation than diagnosed from the Dynamic Global Vegetation Models, likely resulting from the subtractive responses of tropical Rh and NPP to precipitation anomalies that partly offset each other in the net ecosystem exchange (i.e., net ecosystem exchange ≈ Rh − NPP). Variations in other climate variables (e.g., large-scale cloudiness) and natural disturbances (e.g., volcanic eruptions) may induce transient reductions in the temperature–CO₂ coupling, but the relationship is robust during the past 50 y and shows full recovery within a few years after any such major variability event. Therefore, it provides an important diagnostic tool for improved understanding of the contemporary and future global carbon cycle.     

Neuropathological correlate of the “concentric target sign” in MRI of HIV‐associated cerebral toxoplasmosis

Cerebral toxoplasmosis is a frequent cause of focal brain lesions in the setting of immunodeficiency states, particularly acquired immune deficiency syndrome (AIDS), and magnetic resonance imaging (MRI) is an important diagnostic modality to differentiate toxoplasmosis from tuberculoma, and primary central nervous system lymphoma with diverse therapeutic implications. Several imaging patterns have been described in cerebral toxoplasmosis. The “concentric target sign” is a recently described MRI sign on T2‐weighted imaging of cerebral toxoplasmosis that has concentric alternating zones of hypo‐ and hyperintensities. It is believed to be more specific than the well‐known “eccentric target sign” in the diagnosis of cerebral toxoplasmosis and hence more useful in differentiation from other focal brain lesions in the context of AIDS. The concentric target sign, seen in deep parenchymal lesions, is distinct from the surface‐based cortical “eccentric” target sign. The histopathological correlate of the latter has been recently described, but that of the concentric target sign is not known. In this study we describe the neuropathological correlate of this concentric target sign from the postmortem of a 40‐year‐old man with AIDS‐associated cerebral toxoplasmosis. The concentric alternating zones of hypo/hyper/iso/intensities corresponded to zones of hemorrhage/fibrin‐rich necrosis with edema/coagulative compact necrosis/inflammation with foamy histiocytes admixed with hemorrhage forming the outermost zone, respectively. The exclusive specificity of this sign in cerebral toxoplasmosis remains to be further elucidated. J. Magn. Reson. Imaging 2013;38:488–495. © 2013 Wiley Periodicals, Inc.     

Evidence for a significant urbanization effect on climate in China

China has experienced rapid urbanization and dramatic economic growth since its reform process started in late 1978. In this article, we present evidence for a significant urbanization effect on climate based on analysis of impacts of land-use changes on surface temperature in southeast China, where rapid urbanization has occurred. Our estimated warming of mean surface temperature of 0.05 degrees C per decade attributable to urbanization is much larger than previous estimates for other periods and locations. The spatial pattern and magnitude of our estimate are consistent with those of urbanization characterized by changes in the percentage of urban population and in satellite-measured greenness.     

Age of first onset of bipolar disorder: Demographic,family history,and psychosocial correlates

The literature suggests that bipolar elders with early and late onset of the disorder present with different demographic, family history, and psychosocial profiles, which are less well characterized than those for elderly unipolar patients. In this cross-sectional clinical survey, we assessed subjects (n = 74) from the NIMH Clinical Research Center for the Study of Depression in Later Life at Duke University who had a consensus diagnosis of bipolar depression; the primary assessment instrument was the Duke Depression Evaluation Schedule. We found that bipolar subjects with later age of onset reported less family history of psychiatric problems, more comorbid vascular disease, and more instrumental and subjective social support. Stressful life events were more frequent among bipolar subjects with earlier age of depressive symptom onset. This study suggests that early-onset disorder may be characterized by a psychosocial component, whereas organic factors may be particularly important to late-onset bipolar disorder. Depression and Anxiety 7:76–82, 1998. © 1998 Wiley-Liss, Inc.     

Perspectives on depression, mild cognitive impairment, and cognitive decline

CONTEXT: The public health implications of depression and cognitive impairment in late life are enormous. Cognitive impairment and late-life depression are associated with increased risk for subsequent dementia; however, investigations of these phenomena appear to be proceeding along separate tracks. OBJECTIVES AND DATA SOURCE: The National Institute of Mental Health organized the conference "Perspectives on Depression, Mild Cognitive Impairment, and Cognitive Decline" to consider how the varied perspectives might be better integrated to examine the associations among depression, mild cognitive impairment, and cognitive decline and to illuminate the common or distinct mechanisms involved in these associations. DATA SYNTHESIS: The following 2 broad questions were addressed: (1) What gaps in our knowledge have the greatest public health significance? (2) Can we more efficiently use our research dollars and participant resources to fill these gaps? Meeting participants included grantees from the National Institute of Mental Health and the National Institute on Aging and program staff from the National Institute of Mental Health, the National Institute on Aging, and the National Institute of Neurological Disorders and Stroke. CONCLUSIONS: One of the most important recommendations to emerge from the meeting discussions is for increased collaboration among clinical and epidemiological investigators whose work focuses in the area of depression with those working primarily in the area of memory disorders. Directions for future research were identified.