The double-blind sham-controlled study of high-frequency rTMS (20 Hz) for negative symptoms in schizophrenia: negative results

The high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) over the prefrontal cortex is a promising method for the treatment of negative symptoms of schizophrenia. Using double-blind sham-controlled parallel design, we evaluated the effect of HF-rTMS over the left dorsolateral prefrontal cortex (DLPFC) on negative symptoms in patients with schizophrenia. Sixteen schizophrenia patients with predominantly negative symptoms on stable antipsychotic medication were treated with 20 Hz rTMS (90% of motor threshold, 2000 stimuli per session) over ten days within 2 weeks with six weeks follow-up. The effect was assessed using PANSS, CGI, MADRS and neuropsychological tests. We failed to find any significant effect of active rTMS. Sham rTMS showed a trend for improvement over time on positive and negative subscales of PANSS and MADRS. Between-group comparisons failed to reveal any significant differences on any rating scales except a positive subscale of PANSS after 8 weeks. Results from our study did not confirm that HF-rTMS over the left DLPCF affects the negative symptoms of schizophrenia and alternative rTMS approaches are discussed.     

Ectopic over-expression of the maize beta-glucosidase Zm-p60.1 perturbs cytokinin homeostasis in transgenic tobacco

The activity of the phytohormone cytokinin depends on a complex interplay of factors such as its metabolism, transport, stability, and cellular/tissue localization. O-glucosides of zeatin-type cytokinins are postulated to be storage and/or transport forms, and are readily deglucosylated. Transgenic tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) plants were constructed over-expressing Zm-p60.1, a maize beta-glucosidase capable of releasing active cytokinins from O- and N3-glucosides, to analyse its potential to perturb zeatin metabolism in planta. Zm-p60.1 in chloroplasts isolated from transgenic leaves has an apparent K(m) more than 10-fold lower than the purified enzyme in vitro. Adult transgenic plants grown in the absence of exogenous zeatin were morphologically indistinguishable from the wild type although differences in phytohormone levels were observed. When grown on medium containing zeatin, inhibition of root elongation was apparent in all seedlings 14 d after sowing (DAS). Between 14 and 21 DAS, the transgenic seedlings accumulated fresh weight leading later (28-32 DAS) to ectopic growths at the base of the hypocotyl. The development of ectopic structures correlated with the presence of the enzyme as demonstrated by histochemical staining. Cytokinin quantification showed that transgenic seedlings grown on medium containing zeatin accumulate active metabolites like zeatin riboside and zeatin riboside phosphate and this might lead to the observed changes. The presence of the enzyme around the base of the hypocotyl and later, in the ectopic structures themselves, suggests that the development of these structures is due to the perturbance in zeatin metabolism caused by the ectopic presence of Zm-p60.1.     

Neurosteroid modulation of N-methyl-D-aspartate receptors: molecular mechanism and behavioral effects

Glutamate is the main neurotransmitter released at synapses in the central nervous system of vertebrates. Its excitatory role is mediated through activation of specific glutamatergic ionotropic receptors, among which the N-methyl-d-aspartate (NMDA) receptor subtype has attracted considerable attention in recent years. Substantial progress has been made in elucidating the roles these receptors play under physiological and pathological conditions and in our understanding of the functional, structural, and pharmacological properties of NMDA receptors. Many pharmacological compounds have been identified that affect the activity of NMDA receptors, including neurosteroids. This review summarizes our knowledge about molecular mechanisms underlying the neurosteroid action at NMDA receptors as well as about the action of neurosteroids in animal models of human diseases.     

Spatial patterns and intraspecific diversity of the glacial relict legume species <Emphasis Type="Italic">Vavilovia formosa</Emphasis> (Stev.) Fed. in Eurasia

Vavilovia formosa is one of five genera in tribe Fabeae, (Fabaceae, Leguminosae) with close phylogenetic relationships to Pisum. It grows in subalpine and alpine levels in Armenia, Azerbaijan, Georgia, Iran, Iraq, Lebanon, Russia and Turkey and is recognized as an endangered and protected plant. This study was conducted to reveal its intraspecific variability, as well as to predict the past, extant and future species distribution range. We analysed 51 accessions with common phylogenetic markers (trnF-trnL, trnS-trnG, matK, rbcL, psbA-trnH and ITS). These represent in total up to 2551 bp of chloroplast and 664 bp of nuclear sequences per sample. Two populations from Turkey and Armenia were analysed for genetic diversity by AFLP. Leaf morphometry was conducted on 1457 leaflets from 43 specimens. Extracted bioclimatic parameters were used for niche-modelling approach. Analysis of cpDNA revealed two haplotypes, 12 samples from Armenia, Daghestan, Nakhichevan and Iran belonged to H1 group, while 39 samples of all Turkish and part of Armenian were in H2 group. The mean intrapopulation diversity based on AFLP was low (H _E = 0.088) indicating limited outcrossing rate. A significantly positive correlation between geographical latitude and leaf area (\(\rho\) = 0.527, p < 0.05) was found. Niche modelling has shown temporal variation of predicted occurrence across the projected time periods. Vavilovia formosa has suffered a range reduction following climate warming after last glacial maximum, which classify this species as cold-adapted among the Fabeae species as well as a glacial relict.     

Application of size-exclusion chromatography-inductively coupled plasma mass spectrometry for fractionation of element species in seeds of legumes

Fractionation of soluble species of P, Mn, Fe, Co, Ni, Cu, Zn, Se and Mo in pea and lentil seeds was made by on-line hyphenation of size-exclusion chromatography (SEC) and inductively coupled plasma mass spectrometry. Seed samples were extracted with 0.02 mol l(-1) Tris-HCl buffer solution, pH 7.5. SEC was performed on Superdex 75 and Superdex Peptide columns (300 x 10 mm) with the same buffer solution as the mobile phase. Monitoring of oxide ion 47(PO)+ was used for detection of phosphorus compounds. Other elements were detected as ions of 55Mn, 57Fe, 59Co, 62Ni, 65Cu, 66Zn, 82Se and 95Mo nuclides. Elements in individual elution zones were quantified using external calibration. Complete chromatographic recoveries of elements were found in cases of phosphorus, nickel and copper. Substantial parts of manganese and zinc, as well as traces of cobalt, selenium and molybdenum are retained on the column. Injection of EDTA solution removes these elements from the column. Chromatographic profiles of pea and lentil samples are very similar for all elements except Mo. Main element species in the high-molecular-mass region (approx. 190,000 rel. mol. mass unit) were detected in case of Fe. Low-molecular-mass species (<2000 rel. mol. mass unit) as major element forms are typical for Cu and Zn.     

Remote controlled equipment for multiple blood withdrawal in gravitational physiology experiments

Electro-mechanical equipment for multiple blood withdrawal from small experimental animals applied to a centrifuge with maximal 6g gravitational overloading has been developed and tested. The equipment consists of a transmitter and receiver equipped by microcomputers. Active rotor stepping motors are driving four pairs of syringes. It is also possible to measure the instantaneous gravitational force using an accelerometric transducer. This telemetrically regulated blood sampling allows studying selective effects of hypergravity during centrifugation. It can be also used for study of microgravity effects in the animal organism during space flights for the understanding of the mechanism of the changes of the activity of neuroendocrine system and metabolic processes.