Leisure activities, caregiving demands and catecholamine levels in dementia caregivers

This study examined whether satisfaction from leisure activities moderates the relationship between caregiving demands (i.e., hours per day spent caring for a spouse with dementia) and resting levels of the catecholamines norepinephrine (NE) and epinephrine (EPI). Spousal caregivers (n = 107; mean age = 73.95 ± 8.12 years) were assessed in home for plasma levels of NE and EPI, amount of care provided, and leisure satisfaction. Regression was used to determine whether leisure satisfaction moderated the relationship between hours providing care per day and catecholamine levels. A significant interaction was found between hours caregiving and leisure satisfaction for NE, but not for EPI. Post hoc regressions were conducted for both NE and EPI. At low leisure satisfaction, time spent caring for a spouse was positively associated with plasma NE (β = 0.41; p = 0.005) and EPI (β = 0.44; p = 0.003). In contrast, at high levels of satisfaction, time caregiving was not significantly associated with plasma NE (β = -0.08; p = 0.57) or EPI (β = 0.23; p = 0.12). These findings suggest that leisure satisfaction may protect caregivers from increases in catecholamines, which have been implicated in cardiovascular risk. Further support for these findings may impact psychological treatments for distressed caregivers.

Dopaminergic modulation of the human reward system: a placebo-controlled dopamine depletion fMRI study

Reward related behaviour is linked to dopaminergic neurotransmission. Our aim was to gain insight into dopaminergic involvement in the human reward system. Combining functional magnetic resonance imaging with dopaminergic depletion by α-methylparatyrosine we measured dopamine-related brain activity in 10 healthy volunteers. In addition to blood-oxygen-level-dependent (BOLD) contrast we assessed the effect of dopaminergic depletion on prolactin response, peripheral markers for dopamine and norepinephrine. In the placebo condition we found increased activation in the left caudate and left cingulate gyrus during anticipation of reward. In the α-methylparatyrosine condition there was no significant brain activation during anticipation of reward or loss. In α-methylparatyrosine, anticipation of reward vs. loss increased activation in the right insula, left frontal, right parietal cortices and right cingulate gyrus. Comparing placebo versus α-methylparatyrosine showed increased activation in the left cingulate gyrus during anticipation of reward and the left medial frontal gyrus during anticipation of loss. α-methylparatyrosine reduced levels of dopamine in urine and homovanillic acid in plasma and increased prolactin. No significant effect of α-methylparatyrosine was found on norepinephrine markers. Our findings implicate distinct patterns of BOLD underlying reward processing following dopamine depletion, suggesting a role of dopaminergic neurotransmission for anticipation of monetary reward.

Depletion of murine intestinal microbiota: effects on gut mucosa and epithelial gene expression

Background Inappropriate cross talk between mammals and their gut microbiota may trigger intestinal inflammation and drive extra-intestinal immune-mediated diseases. Epithelial cells constitute the interface between gut microbiota and host tissue, and may regulate host responses to commensal enteric bacteria. Gnotobiotic animals represent a powerful approach to study bacterial-host interaction but are not readily accessible to the wide scientific community. We aimed at refining a protocol that in a robust manner would deplete the cultivable intestinal microbiota of conventionally raised mice and that would prove to have significant biologic validity. Methodology/Principal Findings Previously published protocols for depleting mice of their intestinal microbiota by administering broad-spectrum antibiotics in drinking water were difficult to reproduce. We show that twice daily delivery of antibiotics by gavage depleted mice of their cultivable fecal microbiota and reduced the fecal bacterial DNA load by 400 fold while ensuring the animals' health. Mice subjected to the protocol for 17 days displayed enlarged ceca, reduced Peyer's patches and small spleens. Antibiotic treatment significantly reduced the expression of antimicrobial factors to a level similar to that of germ-free mice and altered the expression of 517 genes in total in the colonic epithelium. Genes involved in cell cycle were significantly altered concomitant with reduced epithelial proliferative activity in situ assessed by Ki-67 expression, suggesting that commensal microbiota drives cellular proliferation in colonic epithelium. Conclusion We present a robust protocol for depleting conventionally raised mice of their cultivatable intestinal microbiota with antibiotics by gavage and show that the biological effect of this depletion phenocopies physiological characteristics of germ-free mice.

Serotonin transporter genotype differentially modulates neural responses to emotional words following tryptophan depletion in patients recovered from depression and healthy volunteers

Previous studies have suggested that polymorphism in the serotonin transporter gene (5-HTTLPR) influences responses to serotonergic manipulation, with opposite effects in patients recovered from depression (rMDD) and controls. Here we sought to clarify the neurocognitive mechanisms underpinning these surprising results. Twenty controls and 23 rMDD subjects completed the study; functional magnetic resonance imaging (fMRI) and genotype data were available for 17 rMDD subjects and 16 controls. Following tryptophan or sham depletion, subjects performed an emotional-processing task during fMRI. Although no genotype effects on mood were identified, significant genotype(∗)diagnosis(∗)depletion interactions were observed in the hippocampus and subgenual cingulate in response to emotionally valenced words. In both regions, tryptophan depletion increased responses to negative words, relative to positive words, in high-expression controls, previously identified as being at low-risk for mood change following this procedure. By contrast, in higher-risk low-expression controls and high-expression rMDD subjects, tryptophan depletion had the opposite effect. Increased neural responses to negative words following tryptophan depletion may reflect an adaptive mechanism promoting resilience to mood change following perturbation of the serotonin system, which is reversed in sub-groups vulnerable to developing depressive symptoms. However, this interpretation is complicated by our failure to replicate previous findings of increased negative mood following tryptophan depletion.

Mindfulness meditation counteracts self-control depletion

Mindfulness meditation describes a set of different mental techniques to train attention and awareness. Trait mindfulness and extended mindfulness interventions can benefit self-control. The present study investigated the short-term consequences of mindfulness meditation under conditions of limited self-control resources. Specifically, we hypothesized that a brief period of mindfulness meditation would counteract the deleterious effect that the exertion of self-control has on subsequent self-control performance. Participants who had been depleted of self-control resources by an emotion suppression task showed decrements in self-control performance as compared to participants who had not suppressed emotions. However, participants who had meditated after emotion suppression performed equally well on the subsequent self-control task as participants who had not exerted self-control previously. This finding suggests that a brief period of mindfulness meditation may serve as a quick and efficient strategy to foster self-control under conditions of low resources.

Prevalence of vitamin B12 depletion and deficiency in Liechtenstein

OBJECTIVE: Data about vitamin B12 (B12) deficiency in the general population are scarce. The present study was performed to determine the prevalence of B12 deficiency in the general population of the Principality of Liechtenstein, as well as to identify sub-populations potentially at high risk. DESIGN: Retrospective study. SETTING: Ambulatory setting, population of the Principality of Liechtenstein. SUBJECTS: Seven thousand four hundred and twenty-four patients seeking medical attention whose serum samples were referred for routine work-up in an ambulatory setting were consecutively enrolled. Serum total B12 was determined in all patients in this cohort. In addition, for a subgroup of 1328 patients, serum holotranscobalamin was also measured. Prevalence of B12 deficiency was calculated. Further, multivariate logistical regression models were applied to identify covariates independently associated with B12 deficiency and depletion. RESULTS: Nearly 8 % of the general population was suffering from either B12 depletion or deficiency. The ratio between B12 depletion and deficiency was 2:1 for all age ranges. Pathological changes were detected predominantly in older people. Female gender was a significant predictor of B12 depletion. In the cohort, nearly 40 % exhibited either depletion or deficiency of B12. CONCLUSIONS: B12 depletion and deficiency are common in Liechtenstein, a Central European country. The measurement of biochemical markers represents a cost-efficient and valid assessment of the B12 state. When a deficiency of B12 is diagnosed at an early stage, many cases can be treated or prevented, with beneficial effects on individual outcomes and subsequent potential reductions in health-care costs.

Glucagon, catecholamine and pancreatic polypeptide secretion in type I diabetic recipients of pancreas allografts

Successful pancreas transplantation in type I diabetic patients restores normal fasting glucose levels and biphasic insulin responses to glucose. However, virtually no data from pancreas recipients are available relative to other islet hormonal responses or hormonal counterregulation of hypoglycemia. Consequently, glucose, glucagon, catecholamine, and pancreatic polypeptide responses to insulin-induced hypoglycemia and to stimulation with arginine and secretin were examined in 38 diabetic pancreas recipients, 54 type I diabetic nonrecipients, and 26 nondiabetic normal control subjects. Glucose recovery after insulin-induced hypoglycemia in pancreas recipients was significantly improved. Basal glucagon levels were significantly higher in recipients compared with nonrecipients and normal subjects. Glucagon responses to insulin-induced hypoglycemia were significantly greater in the pancreas recipients compared with nonrecipients and similar to that observed in control subjects. Glucagon responses to intravenous arginine were significantly greater in pancreas recipients than that observed in both the nonrecipients and normal subjects. No differences were observed in epinephrine responses during insulin-induced hypoglycemia. No differences in pancreatic polypeptide responses to hypoglycemia were observed when comparing the recipient and nonrecipient groups, both of which were less than that observed in the control subjects. Our data demonstrate significant improvement in glucose recovery after hypoglycemia which was associated with improved glucagon secretion in type I diabetic recipients of pancreas transplantation.

Rituximab immunotherapy in pemphigus: therapeutic effects beyond B-cell depletion

The anti-CD20 mAb rituximab, first approved for use in B-cell malignancies, is increasingly used to treat a variety of autoimmune diseases. Two studies in this issue investigate the effects of rituximab in pemphigus. Rituximab induces not only a depletion of all B cells and a decline of antidesmoglein autoantibodies but also a decrease in desmoglein-specific T cells. Furthermore, B-cell populations recovered after treatment were modified. These novel aspects may contribute to the clinical responses observed in patients.

Class-switzched B cells display response to therapeutic B-cell depletion in rheumatoid arthritis

Introduction Reconstitution of peripheral blood (PB) B cells after therapeutic depletion with the chimeric anti-CD20 antibody rituximab (RTX) mimics lymphatic ontogeny. In this situation, the repletion kinetics and migratory properties of distinct developmental B-cell stages and their correlation to disease activity might facilitate our understanding of innate and adaptive B-cell functions in rheumatoid arthritis (RA). Methods Thirty-five 'RTX-naïve' RA patients with active arthritis were treated after failure of tumour necrosis factor blockade in an open-label study with two infusions of 1,000 mg RTX. Prednisone dose was tapered according to clinical improvement from a median of 10 mg at baseline to 5 mg at 9 and 12 months. Conventional disease-modifying antirheumatic drugs were kept stable. Subsets of CD19+ B cells were assessed by flow cytometry according to their IgD and CD27 surface expression. Their absolute number and relative frequency in PB were followed every 3 months and were determined in parallel in synovial tissue (n = 3) or synovial fluid (n = 3) in the case of florid arthritis. Results Six of 35 patients fulfilled the European League Against Rheumatism criteria for moderate clinical response, and 19 others for good clinical response. All PB B-cell fractions decreased significantly in number (P < 0.001) after the first infusion. Disease activity developed independently of the total B-cell number. B-cell repopulation was dominated in quantity by CD27-IgD+ 'naïve' B cells. The low number of CD27+IgD- class-switched memory B cells (MemB) in the blood, together with sustained reduction of rheumatoid factor serum concentrations, correlated with good clinical response. Class-switched MemB were found accumulated in flaring joints. Conclusions The present data support the hypothesis that control of adaptive immune processes involving germinal centre-derived, antigen, and T-cell-dependently matured B cells is essential for successful RTX treatment.