Thalamocortical Projections Are Significantly Impaired in the R6/2 Mouse Model of Huntington's Disease.

As Huntington's disease (HD) progresses, there is a significant loss of neurons in the striatum in addition to a distinct thinning of the cerebral cortex. Despite an early presence of sensorimotor deficits in patients with HD, electrophysiological studies designed to assess the integrity of thalamocortical circuits are sparse. Using the R6/2 mouse model of HD, we provide evidence of reduced connectivity between thalamic cells and their targeted cortical regions. Whole-cell patch clamp recordings from ventral anterolateral nucleus (VAL; motor) and ventral posteromedial nucleus (VPM; somatosensory) thalamic neurons in ex vivo brain slices of R6/2 and wild-type (WT) mice revealed that cells in both thalamic nuclei of R6/2 mice exhibited significant differences in passive and active cell membrane properties (smaller cell membrane capacitances, faster decay time constants and increased input resistances) compared with WT cells. Although only cells in the VPM of symptomatic R6/2 mice had more depolarized resting membrane potentials compared with WTs, cells in both nuclei displayed increased excitability in symptomatic, but not presymptomatic, R6/2 mice. Optical activation of VAL and VPM terminals elicited smaller magnitude current responses in cortical pyramidal neurons (CPNs) in both motor cortex (M1CTX) and somatosensory barrel cortex (BCTX) of symptomatic R6/2 mice compared with CPNs in WT mice. Furthermore, we observed a decrease in the frequency of thalamocortical excitatory quantal events in R6/2 BCTX CPNs, with no genotype-dependent differences in AMPA:NMDA response amplitude ratios. These data suggest there is a decrease in the transmission of thalamocortical information that is likely because of impaired neurotransmitter release.

Mechanisms of Non-coenzyme Action of Thiamine: Protein Targets and Medical Significance.

Thiamine (vitamin B1) is a precursor of the well-known coenzyme of central metabolic pathways thiamine diphosphate (ThDP). Highly intense glucose oxidation in the brain requires ThDP-dependent enzymes, which determines the critical significance of thiamine for neuronal functions. However, thiamine can also act through the non-coenzyme mechanisms. The well-known facilitation of acetylcholinergic neurotransmission upon the thiamine and acetylcholine co-release into the synaptic cleft has been supported by the discovery of thiamine triphosphate (ThTP)-dependent phosphorylation of the acetylcholine receptor-associated protein rapsyn, and thiamine interaction with the TAS2R1 receptor, resulting in the activation of synaptic ion currents. The non-coenzyme regulatory binding of thiamine compounds has been demonstrated for the transcriptional regulator p53, poly(ADP-ribose) polymerase, prion protein PRNP, and a number of key metabolic enzymes that do not use ThDP as a coenzyme. The accumulated data indicate that the molecular mechanisms of the neurotropic action of thiamine are far broader than it has been originally believed, and closely linked to the metabolism of thiamine and its derivatives in animals. The significance of this topic has been illustrated by the recently established competition between thiamine and the antidiabetic drug metformin for common transporters, which can be the reason for the thiamine deficiency underlying metformin side effects. Here, we also discuss the medical implications of the research on thiamine, including the role of thiaminases in thiamine reutilization and biosynthesis of thiamine antagonists; molecular mechanisms of action of natural and synthetic thiamine antagonists, and biotransformation of pharmacological forms of thiamine. Given the wide medical application of thiamine and its synthetic forms, these aspects are of high importance for medicine and pharmacology, including the therapy of neurodegenerative diseases.

Serum Concentrations of Vascular Endothelial Growth Factor, Stromal Cell-Derived Factor, Nitric Oxide and Endothelial DNA Proliferation in Development of Microvascular Pathology in Acute African Swine Fever.

There is significant evidence that pathology of the microcirculation occurs in African swine fever (ASF); however, the mechanisms by which it develops are largely unknown. In the present experimental infection study, we show that an increase in vascular permeability in the initial stages of acute ASF is dependent on viraemia and elevation of the concentration of serum nitric oxide (NO). Macrophages activated by ASF virus (ASFV) are stimulated to produce NO and simultaneously to sensitize the endothelial cells through the action of vascular endothelial growth factor Β (VEGFΒ), which is followed by an increase in VEGF-mediated endothelial permeability. In the later stages of disease, the endothelial cells undergo DNA proliferation, which may additionally provoke capillary leakage, point haemorrhages and migration of blood cells into tissues. The possible mechanism of a shift in the cell cycle from the G1 to S and G2 stages could be a direct effect of ASFV. The terminal stages of disease are characterized by triggering of compensatory mechanisms such as stimulation of the synthesis of stromal cell-derived factor-1.

Analysis of Free Amino Acids in Mammalian Brain Extracts.

An optimized method for analysis of free amino acids using a modified lithium-citrate buffer system with a Hitachi L-8800 amino acid analyzer is described. It demonstrates clear advantages over the sodium-citrate buffer system commonly used for the analysis of protein hydrolysates. A sample pretreatment technique for amino acid analysis of brain extracts is also discussed. The focus has been placed on the possibility of quantitative determination of the reduced form of glutathione (GSH) with simultaneous analysis of all other amino acids in brain extracts. The method was validated and calibration coefficient (KGSH) was determined. Examples of chromatographic separation of free amino acids in extracts derived from different parts of the brain are presented.

Thiamine Induces Long-Term Changes in Amino Acid Profiles and Activities of 2-Oxoglutarate and 2-Oxoadipate Dehydrogenases in Rat Brain.

Molecular mechanisms of long-term changes in brain metabolism after thiamine administration (single i.p. injection, 400 mg/kg) were investigated. Protocols for discrimination of the activities of the thiamine diphosphate (ThDP)-dependent 2-oxoglutarate and 2-oxoadipate dehydrogenases were developed to characterize specific regulation of the multienzyme complexes of the 2-oxoglutarate (OGDHC) and 2-oxoadipate (OADHC) dehydrogenases by thiamine. The thiamine-induced changes depended on the brain-region-specific expression of the ThDP-dependent dehydrogenases. In the cerebral cortex, the original levels of OGDHC and OADHC were relatively high and not increased by thiamine, whereas in the cerebellum thiamine upregulated the OGDHC and OADHC activities, whose original levels were relatively low. The effects of thiamine on each of the complexes were different and associated with metabolic rearrangements, which included (i) the brain-region-specific alterations of glutamine synthase and/or glutamate dehydrogenase and NADP+-dependent malic enzyme, (ii) the brain-region-specific changes of the amino acid profiles, and (iii) decreased levels of a number of amino acids in blood plasma. Along with the assays of enzymatic activities and average levels of amino acids in the blood and brain, the thiamine-induced metabolic rearrangements were assessed by analysis of correlations between the levels of amino acids. The set and parameters of the correlations were tissue-specific, and their responses to the thiamine treatment provided additional information on metabolic changes, compared to that gained from the average levels of amino acids. Taken together, the data suggest that thiamine decreases catabolism of amino acids by means of a complex and long-term regulation of metabolic flux through the tricarboxylic acid cycle, which includes coupled changes in activities of the ThDP-dependent dehydrogenases of 2-oxoglutarate and 2-oxoadipate and adjacent enzymes.

Cellular thiamine status is coupled to function of mitochondrial 2-oxoglutarate dehydrogenase.

Decreased thiamine and reduced activity of thiamine diphosphate (ThDP)-dependent 2-oxoglutarate dehydrogenase (OGDH) cause neurodegeneration. We hypothesized on concerted cell-specific regulation of the thiamine metabolism and ThDP-dependent reactions. We identified a smaller thiamine pool, a lower expression of the mitochondrial ThDP transporter, and a higher expression of OGDH in rat astrocytes versus neuroblastoma N2A. According to the data, the astrocytic OGDH may be up-regulated by an increase in intracellular ThDP, while the neuroblastomal OGDH functions at full ThDP saturation. Indeed, in rat astrocytes and brain cortex, OGDH inhibition by succinyl phosphonate (SP) enlarged the pool of thiamine compounds. Increased ThDP level in response to the OGDH inhibition presumably up-regulated the enzyme to compensate for a decrease in reducing power which occurred in SP-treated astrocytes. Under the same SP treatment of N2A cells, their thiamine pool and reducing power were unchanged, although SP action was evident from accumulation of glutamate. The presented data indicate that functional interplay between OGDH, other proteins of the tricarbocylic acid cycle and proteins of thiamine metabolism is an important determinant of physiology-specific networks and their homeostatic mechanisms.

Endoscopic ultrasonography for intra-abdominal textiloma.

INTRODUCTION: The term textiloma is used to describe foreign body (swab) forgotten during surgery. We don't know any case of the description of endoscopic ultrasonography (EUS) for intra-abdominal textiloma. OBJECTIVES: To determine the EUS capabilities in the topical diagnosis of intra-abdominal textiloma. MATERIALS AND METHODS: Patient, female, 57-year-old was admitted to our hospital with post-operative hernia. 10 months before the patient underwent surgery (laparotomy, splenectomy) in another hospital. For ethical reasons, we do not name that hospital. Intra-abdominal lesion has been accidentally revealed by computed tomography during the pre-operative examination prior to hernioplasty. Ultrasound unclear detected hyperechoic lesion with a dense acoustic shadow. The patient was sent to the EUS to clarify the diagnosis and to determine the topography of the lesion, fine-needle aspiration - if required. RESULTS: EUS revealed a hyperechoic corrugated border of the lesion with a dense acoustic shadow - between the gastric wall and the lower surface of the liver. Taking into account preceding surgery EUS suspected textiloma. The patient underwent hernioplasty and revision of the abdominal cavity. Textiloma has been revealed between the stomach and liver. CONCLUSION: EUS correctly diagnosed textiloma and accurately determined its location.

Classic and alternative complement cascades in post-traumatic stress disorder.

Hemolytic activity of classic and alternative complement cascades and blood concentrations of TNF-α, IL-1ß, and IL-6 were measured in patients with post-traumatic stress disorder. The results attest to hyperactivity of the classic complement cascade associated with elevated content of proinflammatory cytokines and hypoactivation of the alternative complement cascade in patients with post-traumatic stress disorder in comparison with healthy individuals.

Classical pathway complement activity in Familial Mediterranean fever.

OBJECTIVES: The present study emphasizes the important role of the immune reactions in the pathogenesis of Familial Mediterranean fever. In the present study, the total hemolytic activity of the complement and the activities of individual complement components, C1, C2, C3, and C4, were determined in the blood serum of 32 patients with FMF and 28 healthy subjects. DESIGN AND METHODS: Hemolytic assay was applied, measuring THAC and individual complement components' activities. The patients were divided into 3 groups upon the regularity of colchicine therapy: patients receiving regular, irregular and not receiving colchicine treatment for at least 1 year. RESULTS: No significant changes in the hemolytic activities of the C1, C2, C3, and C4 complement components were found between the healthy subjects and those FMF patients, who were receiving regular colchicine treatment. CONCLUSIONS: Our data obtained have raised a number of important questions relevant to FMF pathogenesis and once again confirms the efficiency of regular colchicine treatment.