GABA metabolism and its role in gamma-band oscillatory activity during auditory processing: An MRS and EEG study.

Gamma-aminobutyric acid (GABA) and glutamate are believed to have inhibitory and exhibitory neuromodulatory effects that regulate the brain's response to sensory perception. Furthermore, frequency-specific synchronization of neuronal excitability within the gamma band (30-80 Hz) is attributable to a homeostatic balance between excitation and inhibition. However, our understanding of the physiological mechanism underlying gamma rhythms is based on animal models. Investigations of the relationship between GABA concentrations, glutamate concentrations, and gamma band activity in humans were mostly restricted to the visual cortex and are conflicting. Here, we performed a multimodal imaging study combining magnetic resonance spectroscopy (MRS) with electroencephalography (EEG) in the auditory cortex. In 14 healthy subjects, we investigated the impact of individual differences in GABA and glutamate concentration on gamma band response (GBR) following auditory stimulus presentation. We explored the effects of bulk GABA on the GBR across frequency (30-200 Hz) and time (-200 to 600 ms) and found no significant relationship. Furthermore, no correlations were found between gamma peak frequency or power measures and metabolite concentrations (GABA, glutamate, and GABA/glutamate ratio). These findings suggest that, according to MRS measurements, and given the auditory stimuli used in this study, GABA and glutamate concentrations are unlikely to play a significant role in the inhibitory and excitatory drive in the generation of gamma band activity in the auditory cortex. Hum Brain Mapp 38:3975-3987, 2017. © 2017 Wiley Periodicals, Inc.

[Iron substitution in outpatients in Switzerland: Increase of costs associated with intravenous administration]. / Ambulante Eisensubstitution in der Schweiz - Kostensteigerung infolge venöser Applikation.

Iron anaemia and iron-deficient erythropoiesis are treated with oral iron supplements. For chronic haemodialysis or in the case of therapy failure or intolerance to oral iron therapy, intravenous supplements are administered. The costs of iron supplements borne by statutory health care insurance had strongly increased during the observation period from 2006 to 2010. Based on the invoice data of a large health insurance company with a market share of around 18 %, prescription data of iron preparations and laboratory tests were analysed and extrapolated to the Swiss population. During the 5-year observation period, costs of intravenous iron substitution increased by 16.5 m EUR (340.3 %) and the number of individuals treated by 243.5 %. A sharp rise was observed in women of menstruating age, which was mainly due to prescriptions issued by primary care physicians. More than 8 % of intravenous iron substitutions were administered without prior laboratory analysis,and must therefore be regarded as off-label use. A cost-benefit analysis is needed to demonstrate the additional value of intravenous over oral iron supplementation, and intravenous iron supplementation should be administered only to patients with proven iron deficiency.

A shift from oral to intravenous iron supplementation therapy is observed over time in a large swiss cohort of patients with inflammatory bowel disease.

BACKGROUND: In 2007, leading international experts in the field of inflammatory bowel disease (IBD) recommended intravenous (IV) iron supplements over oral (PO) ones because of superior effectiveness and better tolerance. We aimed to determine the percentage of patients with IBD undergoing iron therapy and to assess the dynamics of iron prescription habits (IV versus PO). METHODS: We analyzed anonymized data on patients with Crohn's disease and ulcerative colitis extracted from the Helsana database. Helsana is a Swiss health insurance company providing coverage for 18% of the Swiss population (1.2 million individuals). RESULTS: In total, 629 patients with Crohn's disease (61% female) and 398 patients with ulcerative colitis (57% female) were identified; mean observation time was 31.8 months for Crohn's disease and 31.0 months for ulcerative colitis patients. Of all patients with IBD, 27.1% were prescribed iron (21.1% in males; 31.1% in females). Patients treated with steroids, immunomodulators, and/or anti-tumor necrosis factor drugs were more frequently treated with iron supplements when compared with those not treated with any medications (35.0% versus 20.9%, odds ratio, 1.94; P < 0.001). The frequency of IV iron prescriptions increased significantly from 2006 to 2009 for both genders (males: from 2.6% to 10.1%, odds ratio = 3.84, P < 0.001; females: from 5.3% to 12.1%, odds ratio = 2.26, P = 0.002), whereas the percentage of PO iron prescriptions did not change. CONCLUSIONS: Twenty-seven percent of patients with IBD were treated with iron supplements. Iron supplements administered IV were prescribed more frequently over time. These prescription habits are consistent with the implementation of guidelines on the management of iron deficiency in IBD.