Isolated Schwannoma of the Olfactory Groove: A Case Report

Introduction Schwannoma of the olfactory groove is an extremely rare tumor that can share a differential diagnosis with meningioma or neuroblastoma. Objectives The authors present a case of giant schwannoma involving the anterior cranial fossa and ethmoid sinuses. Case Report The patient presented with a 30-month history of left nasal obstruction, anosmia, and sporadic ipsilateral bleeding. Computed tomography of the paranasal sinuses revealed expansive lesion on the left nasal cavity extending to nasopharynx up to ethmoid and sphenoid sinuses bilaterally with intraorbital and parasellar extension to the skull base. Magnetic resonance imaging scan confirmed the expansive tumor without dural penetration. Biopsy revealed no evidence of malignancy and probable neural cell. Bifrontal craniotomy was performed combined with lateral rhinotomy (Weber-Ferguson approach), and the lesion was totally removed. The tumor measured 8.0 4.3 3.7 cm and microscopically appeared as a schwannoma composed of interwoven bundles of elongated cells (Antoni A regions)mixed with less cellular regions (Antoni B). Immunohistochemical study stained intensively for vimentin and S-100. Conclusion Schwannomas of the olfactory groove are extremely rare, and the findings of origin of this tumor is still uncertain but recent studies point most probably to the meningeal branches of trigeminal nerve or anterior ethmoidal nerves. .

The role of the uncoupling protein 1 (UCP1) on the development of obesity and type 2 diabetes mellitus / Papel da proteína desacopladora 1 (UCP1) no desenvolvimento da obesidade e do diabetes melito tipo 2

It is well established that genetic factors play an important role in the development of both type 2 diabetes mellitus (DM2) and obesity, and that genetically susceptible subjects can develop these metabolic diseases after being exposed to environmental risk factors. Therefore, great efforts have been made to identify genes associated with DM2 and/or obesity. Uncoupling protein 1 (UCP1) is mainly expressed in brown adipose tissue, and acts in thermogenesis, regulation of energy expenditure, and protection against oxidative stress. All these mechanisms are associated with the pathogenesis of DM2 and obesity. Hence, UCP1 is a candidate gene for the development of these disorders. Indeed, several studies have reported that polymorphisms -3826A/G, -1766A/G and -112A/C in the promoter region, Ala64Thr in exon 2 and Met299Leu in exon 5 of UCP1 gene are possibly associated with obesity and/or DM2. However, results are still controversial in different populations. Thus, the aim of this study was to review the role of UCP1 in the development of these metabolic diseases.

Está bem estabelecido que fatores genéticos têm papel importante no desenvolvimento do diabetes melito tipo 2 (DM2) e obesidade e que indivíduos suscetíveis geneticamente podem desenvolver essas doenças metabólicas após exposição a fatores de risco ambientais. Assim, grandes esforços têm sido feitos para a identificação de genes associados ao DM2 e/ou à obesidade. A proteína desacopladora 1 (UCP1) é principalmente expressa no tecido adiposo marrom e atua na termogênese, regulação do gasto energético e proteção contra o estresse oxidativo, mecanismos associados tanto à patogênese do DM2 como à obesidade. Portanto, UCP1 é um gene candidato para o desenvolvimento dessas doenças. De fato, diversos estudos relataram que os polimorfismos -3826A/G, -1766A/G e -112A/C na região promotora, Ala64Thr no éxon 2 e Met299Leu no éxon 5 do gene UCP1 estão possivelmente associados à obesidade e/ou ao DM2. Entretanto, os resultados são ainda controversos em diferentes populações. Então, o objetivo deste estudo foi revisar o papel da UCP1 no desenvolvimento dessas doenças metabólicas.

Ion channelopathies in endocrinology: recent genetic findings and pathophysiological insights / Canalopatias em endocrinologia: achados genéticos recentes e fisiopatologia

Ion channels serve diverse cellular functions, mainly in cell signal transduction. In endocrine cells, these channels play a major role in hormonal secretion, Ca2+-mediated cell signaling, transepithelial transport, cell motility and growth, volume regulation and cellular ionic content and acidification of lysosomal compartments. Ion channel dysfunction can cause endocrine disorders or endocrine-related manifestations, such as pseudohypoaldosteronism type 1, Liddle syndrome, Bartter syndrome, persistent hyperinsulinemic hypoglycemia of infancy, neonatal diabetes mellitus, cystic fibrosis, Dent's disease, hypomagnesemia with secondary hipocalcemia, nephrogenic diabetes insipidus and, the most recently genetically identified channelopathy, thyrotoxic hypokalemic periodic paralysis. This review briefly recapitulates the membrane action potential in endocrine cells and offers a short overview of known endocrine channelopathies with focus on recent progress regarding the pathophysiological mechanisms and functional genetic defects.

Canais iônicos auxiliam diferentes funções celulares, principalmente na transdução de sinal. Nas células endócrinas, esses canais têm funções importantes na secreção hormonal, sinalização do Ca2+, transporte transepitelial, regulação da motilidade, volume e conteúdo iônico celular e da acidificação do compartimento lisossomal (pH). Como esperado, as alterações nos canais iônicos podem causar distúrbios endocrinológicos, como pseudo-hipoaldosteronismo tipo 1, síndrome de Liddle, síndrome de Bartter, hipoglicemia hiperinsulinêmica da infância, diabetes melito neonatal, fibrose cística, doença de Dent, hipomagnesemia com hipocalcemia secundária, diabetes insípido nefrogênico e paralisia periódica tirotóxica hipocalêmica. Este artigo propõe uma breve revisão das canalopatias endócrinas conhecidas, com foco particular nos recentes progressos no conhecimento dos mecanismos fisiopatológicos adquirido a partir das alterações funcionais encontradas.

Effects of Mixed Herbal Extracts from Parched Puerariae Radix, Gingered Magnoliae Cortex, Glycyrrhizae Radix and Euphorbiae Radix (KIOM-79) on Cardiac Ion Channels and Action Potentials

KIOM-79, a mixture of ethanol extracts from four herbs (parched Puerariae radix, gingered Magnoliae cortex, Glycyrrhizae radix and Euphorbiae radix), has been developed for the potential therapeutic application to diabetic symptoms. Because screening of unexpected cardiac arrhythmia is compulsory for the new drug development, we investigated the effects of KIOM-79 on the action potential (AP) and various ion channel currents in cardiac myocytes. KIOM-79 decreased the upstroke velocity (Vmax) and plateau potential while slightly increased the duration of action potential (APD). Consistent with the decreased Vmax and plateau potential, the peak amplitude of Na+ current (INa) and Ca2+ current (ICa,L) were decreased by KIOM-79. KIOM-79 showed dual effects on hERG K+ current; increase of depolarization phase current (Idepol) and decreased tail current at repolarization phase (Itail). The increase of APD was suspected due to the decreased Itail. In computer simulation, the change of cardiac action potential could be well simulated based on the effects of KIOM-79 on various membrane currents. As a whole, the influence of KIOM-79 on cardiac ion channels are minor at concentrations effective for the diabetic models (0.1-10 microg/mL). The results suggest safety in terms of the risk of cardiac arrhythmia. Also, our study demonstrates the usefulness of the cardiac computer simulation in screening drug-induced long-QT syndrome.

Effects of Mixed Herbal Extracts from Parched Puerariae Radix, Gingered Magnoliae Cortex, Glycyrrhizae Radix and Euphorbiae Radix (KIOM-79) on Cardiac Ion Channels and Action Potentials

KIOM-79, a mixture of ethanol extracts from four herbs (parched Puerariae radix, gingered Magnoliae cortex, Glycyrrhizae radix and Euphorbiae radix), has been developed for the potential therapeutic application to diabetic symptoms. Because screening of unexpected cardiac arrhythmia is compulsory for the new drug development, we investigated the effects of KIOM-79 on the action potential (AP) and various ion channel currents in cardiac myocytes. KIOM-79 decreased the upstroke velocity (Vmax) and plateau potential while slightly increased the duration of action potential (APD). Consistent with the decreased Vmax and plateau potential, the peak amplitude of Na+ current (INa) and Ca2+ current (ICa,L) were decreased by KIOM-79. KIOM-79 showed dual effects on hERG K+ current; increase of depolarization phase current (Idepol) and decreased tail current at repolarization phase (Itail). The increase of APD was suspected due to the decreased Itail. In computer simulation, the change of cardiac action potential could be well simulated based on the effects of KIOM-79 on various membrane currents. As a whole, the influence of KIOM-79 on cardiac ion channels are minor at concentrations effective for the diabetic models (0.1-10 microg/mL). The results suggest safety in terms of the risk of cardiac arrhythmia. Also, our study demonstrates the usefulness of the cardiac computer simulation in screening drug-induced long-QT syndrome.

Study of P. falciparum-infected erythrocytes and induced anisotropies under optical and fluid forces.

BACKGROUND & OBJECTIVES: The effect of P. falciparum on erythrocytes has been studied for a long time at the population level but actual studies at the single cell level remain largely unexplored. The aim of this study was to address the host-parasite relationship at the single cell level under two different kinds of forces, an optical force and a fluid force. The questions addressed were about the basic host-parasite interactions, but our findings have larger implications in diverse fields of parasite biology. METHODS: Erythrocytes were monitored under optical forces (using optical tweezers) and fluid forces (using microfluidic chambers) and dynamical images were captured in real-time video clips. These videos were then split into their respective frames so as to yield temporal information and various parameters pertaining to membrane structure, ionic imbalance and interaction with different forces were studied. RESULTS: The results of this study mainly bring to fore the inherent differences between infected and normal cell populations at the single cell level under various external forces. We probed three different criteria folding times, rotation speeds and rolling frequency to show inherent difference in various cell populations and also the dependence of the above to the cycle of the parasite. INTERPRETATION & CONCLUSION: This study portrays the importance of single cell observations pertaining to the host-parasite relationship. It shows the effect the malarial parasite has on erythrocytes and how the intrinsic property of the infected and its neighbouring uninfected cells change as compared to normal erythrocytes. There are thus implications in the fields of cytoadherence, parasite invasions and host immune evasion.

Arritmias e genética / Arrhythmias and genetics

Os recentes avanços na área de genética em arritmias têm possibilitado a descoberta de novas síndromes clínicas em pacientes sem cardiopatia estrutural aparente. Uma das principais causas tem sido o desequilíbrio das correntes iônicas gerado a partir de defeitos genéticos, polimorfismos, intervenções terapêuticas ou anormalidades estruturais, que podem ocasionar vários fenótipos arritmogênicos, como arritmias cardíacas, síncope e morte súbita. Os estudos genéticos estão na sua curva de aprendizado e a lista de arritmias cardíacas e seus aspectos genéticos ainda está longe de ser concluída. Discutiremos neste capítulo as principais doenças do ritmo cardíaco que, até o momento, apresentam implicações com aspectos genéticos

Canales de iones / Ions channels

Los canales de iones son glucoproteínas estructurales de la membrana celular que participan en la función, sobre todo de células excitables, para generar el potencial de acción y además ayudan a mantener el equilibrio de iones y de agua en los espacios intra y extracelulares. En la presente revisión se mencionan, entre otros aspectos, su estructura, los principios básicos de su función y algunas de las enfermedades hereditarias que ocurren habitualmente por una formación anormal de estas estructuras. La habilidad que tenemos de pensar y movernos depende de los cambios de voltaje iniciados por la movilización de iones, lo cual regula la función nerviosa y muscular. Por mucho tiempo se ha sabido que estos canales son blanco de manipulación por varios fármacos aplicados, sobre todo, a nivel de la clínica cardiovascular; otros medicamentos, usados ampliamente en forma secundaria, también pueden alterar la función de los canales induciendo efectos colaterales que pueden ser graves. Todos estos aspectos y algunos otros se mencionan en la presente revisión

Enfermedades de los canales ionicos / Ionic-channel diseases

Este trabajo clasifica diversas enfermedades causadas por un anormal funcionamento en los canales iónicos activados por voltaje o neurotransmisores. Numerosos procesos fisiológicos dependen del normal funcionamiento de canales iónicos, funciones que son más aparentes en los epitelios absortivos y secretorios y en los tejidos excitables como nervio y músculo. Los estudios que combinan los registros electrofisiológicos con la biologia molecular han aclarado la estructura de las proteínas constituyentes de los canales iónicos y la expresión de los mismos. Estos estudios han revelado diversas estructuras responsables de los procesos de permeación, selectividad, activación, inactivación y bloqueo de los canales iónicos. Por medio de estos estudios los canales anormales y sus efectos moleculares pueden ser identificados. Los recientes avances en esta área permiten una clasificación más racional para las enfermedades de los canales iónicos y los resultados podrían ser útiles para su tratamiento en el futuro.

Diameter of the mammalian porin channel in open and "closed" states: direct measurement at the single channel level in planar lipid bilayer

Porin isolated from bovine skeletal muscle was reconstituted in planar lipid bilayers under voltage clamp conditions. A set of non-electrolytes were used as molecular probes for determining the pore diameter. The maximal diameter of the open channel was estimated to be 3.02 + 0.26 nm. As observed for other porin channels, a large transmembrane potential drove the channel into a "closed" state. The channel transition to the low conductance (closed) state was followed by a decrease in the maximal diameter of the channel to 2.4 +- 0.08 nm.

Hurst analysis in the study of ion channel kinetics

Ion channels are protein molecules which can assume distinct open and closed conformational states. The transitions between these states can be controlled by the electrical field, ions and/or drugs. Records of unitary current events show that short open-time intervals are frequently adjacent to much longer closed-time intervals, and vice-versa, suggesting that the kinetic process has memory, i.e., the intervals are correlated in time. here the rescaled range analysis (R/S Hurst analysis) is proposed as a method to test for correlation. Simulations were performed with a two-state Markovian model, which has no memory. The calculated Hurst coefficients (H) presented a mean + or - SD value of 0.493 + or - 0.025 (N = 100). For the Ca2+ -activated K+ channels of Leydig cells, H wass equal to 0.75, statistically different (1 percent level) from that calculated for the memoryless proces. Randomly shuffling the experimental data resulted in an H = 0.55, not significantly different (1 percent level) from that found for the two-state Markovian model. For a linear three-state Markovian model, H was equal to 0.548 + or - 0.017 (N = 15), agin not significantly different (1 percent level) from that of the memoryless proces. Although the tree-state Markovian model adequately describes the open-and closed-time distributions, it does not account for the correlation found in this Ca2+ -activatedK+ channel. Our results ilustrate the efficacy of the R/S analysis in determining whether successive opening and closing events are correlated in time and can be of help in deciding which odel should be used to describe the kinetics of ion channels

Canales para iones en las membranas celulares: algunos aspectos de interés clínico / Ionic channels in cellular membranes: somo aspects of clinical relevance

En el presente artículo se revisan brevemente las principales características de los canales para iones en las membranas celulares, su participación en diversos eventos fisiológicos y fisiopatológicos y se muestran ciertos aspectos de importancia clínica derivados de su estudio

Canales iónicos en células no excitables / Ion channels in non excitable cells

Several distinct types of voltage-gated and second-messenger-operated K+, Ca2+, Na+ and Cl- channels exist in electrically non excitable cells such as those of the hematopoietic lineage. In these cells ion channels mediate cellular functions involving intraceiiuiar biochemical responses, rather than rapid electrical signaling. The presence of the channels is required for several basic functions, such as activation, secretion of lymphokines, mitogenesis, the regulation of cell volume and the mechanisms of resistance to chemotherapeutic agents. Here IN we review the patch-clamp method for studying many characteristics of these ionic channels, particularly in blood cells.

Modulation of baroreceptor activity by ionic and paracrine mechanisms: an overview

1. The primary mechanism of activation of baroreceptors is mechanical deformation during vascular stretch. In addition, baroreceptor activity is modulated by ionic mechanisms and by neurohumoral and paracrine factors that act directly on the nerve endings. 2. Ionic mechanisms play a major role in causing baroreceptor activity to decline during a sustained increase in arterial pressure (adaptation) and in the suppression of activity that occurs after pressure returns to basal levels (post-excitatory depression). Activation of a 4-aminopyridine-sensitive K+ channel contributes to adaptation, whereas activation of an electrogenic sodium pump is responsible for post-excitatory depression. 3. Factors released from vascular endothelium exert powerful effects on baroreceptor sensitivity. Prostacyclin increases baroreceptor sensitivity and contributes to baroreceptor activation during vascular stretch. Nitric oxide, endothelin and oxygen-derived free radicals suppress baroreceptor activity particularly at high levels of arterial pressure. The sympathetic neurotransmitter norepinephrine modulates baroreceptor activity: a) indirectly through its vasoconstrictor action, b) directly by binding to alpha-adrenergic receptors on the nerve endings, and c)through release of a cyclooxygenase metabolite, possibly prostacyclin, from endothelium. 4. Endothelial dysfunction contributes to baroreceptor impairment in atherosclerosis and in chronic hypertension. Loss of the excitatory influence of prostacyclin and increased formation of free radicals and possibly endothelin contribute to the baroreceptor dysfunction. Platelets aggregating at sites of endothelial damage in the carotid sinus release a stable diffusible factor that impairs baroreceptor sensitivity. 5. Therapeutic interventions may alter baroreceptor sensitivity through paracrine mechanisms. Treatment of hypertension or atherosclerosis may improve baroreceptor sensitivity by restoring endothelial function. Antiplatelet agents may enhance baroreceptor sensitivity. Antidepressant agents may decrease baroreceptor sensitivity by inhibiting prostacyclin and/or stimulating nitric oxide formation, which may contribute to dysregulation of the circulation in patients treated for depression.