GABAA receptor associated protein (GABARAP) modulates TRPV1 expression and channel function and desensitization.

Transient receptor potential vanilloid (TRPV1) transduces noxious chemical and physical stimuli in high-threshold nociceptors. The pivotal role of TRPV1 in the physiopathology of pain transduction has thrust the identification and characterization of interacting partners that modulate its cellular function. Here, we report that TRPV1 associates with gamma-amino butyric acid A-type (GABA(A)) receptor associated protein (GABARAP) in HEK293 cells and in neurons from dorsal root ganglia coexpressing both proteins. At variance with controls, GABARAP augmented TRPV1 expression in cotransfected cells and stimulated surface receptor clustering. Functionally, GABARAP expression attenuated voltage and capsaicin sensitivity of TRPV1 in the presence of extracellular calcium. Furthermore, the presence of the anchor protein GABARAP notably lengthened the kinetics of vanilloid-induced tachyphylaxia. Notably, the presence of GABARAP selectively increased the interaction of tubulin with the C-terminal domain of TRPV1. Disruption of tubulin cytoskeleton with nocodazole reduced capsaicin-evoked currents in cells expressing TRPV1 and GABARAP, without affecting the kinetics of vanilloid-induced desensitization. Taken together, these findings indicate that GABARAP is an important component of the TRPV1 signaling complex that contributes to increase the channel expression, to traffic and cluster it on the plasma membrane, and to modulate its functional activity at the level of channel gating and desensitization.

Polycaprolactone/gelatin-based scaffolds with tailored performance: in vitro and in vivo validation.

Nanofibrous scaffolds composed of polycaprolactone (PCL) and gelatin (Ge) were obtained through a hydrolytic assisted electrospinning process. The PCL-to-Ge proportion (100/0 to 20/80), as well as the dissolution time (24, 48, 72, 96, 120 h) into a 1:1 formic/acetic acid solvent before electrospinning were modified to obtain the different samples. A strong influence of these factors on the physicochemical properties of the scaffolds was observed. Higher Ge percentage reduced crystallinity, allowed a uniform morphology and increased water contact angle. The increase in the dissolution time considerably reduced the molar mass and, subsequently, fibre diameter and crystallinity were affected. During in vitro biocompatibility tests, higher cell adhesion and proliferation were found for the 60/40, 50/50 and 40/60 PCL/Ge compositions that was corroborated by MTT assay, fluorescence and microscopy. A weakened structure, more labile to the in vitro degradation in physiologic conditions was found for these compositions with higher dissolution times (72 and 96 h). Particularly, the 40/60 PCL/Ge scaffolds revealed an interesting progressive degradation behaviour as a function of the dissolution time. Moreover, these scaffolds were non-inflammatory, as revealed by the pyrogen test and after the 15-day subcutaneous in vivo implantation in mice. Finally, a reduction of the scar tissue area after infarction was found for the 40/60 PCL/Ge scaffolds electrospun after 72 h implanted in rat hearts. These results are especially interesting and represent a feasible way to avoid undesired inflammatory reactions during the scaffold assimilation.

Primary rhabdomyosarcoma of the thyroid in an adult with auricular thrombosis.

INTRODUCTION: Rhabdomyoscarcoma (RMS) is the most common soft-part tumour in children, however, it is infrequent in adults. Thyroid involvement is exceptional and only four cases have been reported: two primary RMS in children and another two cases in young adults with RMS metastasis to the thyroid. We report the first case in the literature of a primary adult RMS with thyroid involvement and superior vena cava syndrome. CASE PRESENTATION: A 67-year-old male was admitted for an oedema of the arm extending to the laterocervical region. Computed tomography showed a 6cm mass in the hemithyroid with venous thrombosis to the auricle. Fine-needle aspiration was compatible with Bethesda category III. Surgery revealed a stone-hard consistency thyroid. An intraoperative biopsy showed an undifferentiated neoplasia, and no additional surgical intervention was undertaken. The patient died 48hours later. Definitive histology showed a RMS. DISCUSSION: Venous thrombosis due to a thyroid tumour is infrequent. The scarce information in the literature recommends that thyroid carcinomas with auricular thrombosis be resected as soon as they are diagnosed. However, in cases of anaplastic or poorly differentiated carcinomas is controversial. Had there been a preoperative diagnosis in the histology in our case, surgery would not have been indicated.

Solubility Enhancement of a Poorly Water Soluble Drug by Forming Solid Dispersions using Mechanochemical Activation.

Mechanochemical activation is a practical cogrinding operation used to obtain a solid dispersion of a poorly water soluble drug through changes in the solid state molecular aggregation of drug-carrier mixtures and the formation of noncovalent interactions (hydrogen bonds) between two crystalline solids such as a soluble carrier, lactose, and a poorly soluble drug, indomethacin, in order to improve its solubility and dissolution rate. Samples of indomethacin and a physical mixture with a weight ratio of 1:1 of indomethacin and lactose were ground using a high speed vibrating ball mill. Particle size was determined by electron microscopy, the reduction of crystallinity was determined by calorimetry and transmission electron microscopy, infrared spectroscopy was used to find evidence of any interactions between the drug and the carrier and the determination of apparent solubility allowed for the corroboration of changes in solubility. Before grinding, scanning electron microscopy showed the drug and lactose to have an average particle size of around 50 and 30 µm, respectively. After high speed grinding, indomethacin and the mixture had a reduced average particle size of around 5 and 2 µm, respectively, showing a morphological change. The ground mixture produced a solid dispersion that had a loss of crystallinity that reached 81% after 30 min of grinding while the drug solubility of indomethacin within the solid dispersion increased by 2.76 fold as compared to the pure drug. Drug activation due to hydrogen bonds between the carboxylic group of the drug and the hydroxyl group of lactose as well as the decrease in crystallinity of the solid dispersion and the reduction of the particle size led to a better water solubility of indomethacin.

Low-frequency white noise generators for biomedical systems.

There is a need for electronic noise sources for investigation of biological and medical research equipment. Such sources need to provide a "white noise" output with a frequency spectrum flat from one to one hundred Hertz. The present paper describes two designs of such sources. The spectra are measured and compared. One course is the reverse-biased junction of a transistor base-emitter junction operating in the avalanche mode. The second source is a MOS IC pseudo-random digital signal. In both cases, the spectra are presented. The choice between the two sources depends upon the application. For most applications, either source is shown to be satisfactory.

[Study of anti-loxosceles serum action on hemolytic and ulcero-necrotic cutaneous effects of Loxosceles laeta venom]. / Estudio de la acción del suero antiloxoscélico sobre los efectos hemolíticos y ulcero-necróticos cutáneos producidos por el veneno de la araña Loxosceles laeta.

The action of an anti-loxosceles serum on in vitro human red blood cell hemolysis and on the development of ulcero-necrotic lesions in rabbit skin, induced by loxosceles laeta venom, was studied. An 81 +/- 3% hemolysis was obtained after 72 h incubation of a 2.5% Rh+ red blood cell solution with the equivalent of one Loxosceles laeta venom gland. This parameter was not modified adding anti-loxosceles serum before, along with or after the venom (79.7 +/- 0.8, 77.3 +/- 2.1 and 80.7 +/- 0.7% respectively). After the intradermic injection of a minimal necrotizing venom dose in rabbits, a skin necrotic lesion appeared. This lesion did not appear if anti-loxosceles serum was injected together with the venom; if the serum was injected one hour after the venom, the resulting skin lesion was inflammatory but not necrotic. It is concluded that anti-loxosceles serum does not inhibit loxosceles venom induced hemolysis and causes a time dependent inhibition on skin necrotic lesions.

[Typhoid fever in children: association with blood phenotypes ABO, Rh and MNSs]. / Fiebre tifoidea en el niño: asociaciones de los fenotipos sanguineos ABO, Rh y MNSs.

The hypothesis that blood phenotype B is associated to typhoid fever either directly or interacting with other phenotypes of the Rh or MNSs blood systems was tested. 256 children from the Northern Area of Santiago (Chile) with bacteriologically confirmed typhoid fever and 329 afebrile controls matched by age and gender from the same population, were studied. Association was found between phenotype RH3 and protection against disease for the whole group (OR = 0.67; p < 0.042) and for males (OR = 0.05; p = 0.014) although the gender-RH3 interaction was at the limit of significance. RH8 and Ss phenotypes were associated to increased susceptibility (OR = 1.83; p < 0.034 and OR = 1.56; p = 0.01, respectively). Controlling RH3 and Ss phenotypes by B, increased their effects (OR = 0.26; p = 0.04 and OR = 3.42; p = 0.026, respectively), but interactions did not reach statistical significance. These results show a susceptibility cline whose implications and applicability deserve further studies. A high proportion of S. paratyphi B (23.8%) appeared in this series, which may imply sample heterogeneity. The meaning of these findings need further epidemiological and genetic studies.