Cuban Epidemic Neuropathy: Insights into the Toxic-Nutritional Hypothesis through International Collaboration.

From 1991 to 1993, an epidemic of optic and peripheral neuropathy-the largest of the century-broke out in Cuba, affecting more than 50,000 people. Initially the main clinical features were decreased visual acuity, central and cecocentral scotomas, impaired color vision and absence of the papillomacular bundle. Later, peripheral and mixed optic-peripheral forms began to appear. Due to the magnitude of the epidemic, the Cuban government requested help from the international community at the 46th World Health Assembly in 1993. PAHO and WHO immediately responded by sending a mission of international experts. Several hypotheses regarding the pathogenesis of Cuban epidemic neuropathy were put forward including: toxic, nutritional, genetic and infectious. The authors refer to extensive studies by researchers sponsored by the Cuban government and PAHO/WHO, joined by scientists from several other countries, including the USA. This paper describes their multidisciplinary work, particularly devoted to investigating the hypothesis of a primary toxic-nutritional cause of the epidemic. Clinical aspects, such as case definition and clinical description, were vital issues from the start. Cuban physicians who first examined patients received a clear impression of its toxic-nutritional origin, later confirmed by international experts. Research then focused on the mechanisms contributing to damage under the toxic-nutritional hypothesis. These included injuries to the mitochondrial oxidative phosphorylation pathway, nutritional deficiencies, excitotoxicity, formate toxicity and dysfunction of the blood-brain barrier. It was expected that the results of such international collaboration into this major health problem would also shed more light on mechanisms underlying other nutritional or tropical myeloneuropathies. KEYWORDS Optic neuritis, optic neuropathy, peripheral neuropathy, neurotoxicity syndromes, disease outbreaks, international cooperation, Cuba Erratum: Page 30, first complete paragraph, line 7, "Two models were developed independently by Cuban researchers" should read "Two models were developed independently by AAS and AGQ."

Fluoxetine Treatment in Rats Increases the Rate of Taurine Transport in Mononuclear Cells.

Fluoxetine, a selective serotonin reuptake inhibitor antidepressant, modulates the mitogen-induced proliferation of lymphocytes. Lymphocytes contain taurine and express taurine transporter (TauT). Among the effects of taurine on lymphocytes are protection against oxidants and regulation of the inflammatory aspects of the immune response. Our aim was to determine the influence of fluoxetine treatment on taurine transport, and to determine the presence of TauT in the mononuclear cells of rats. METHODS: Male adult Sprague-Dawley rats were treated with fluoxetine 10 mg/kg i.p. for 1, 2, and 3 weeks. The cells were obtained by density gradients. [3H]Taurine was used for transport assays. Amino acid levels were determined by high-performance liquid chromatography. Immunolabeling of CD4+, CD8+, and TauT was performed. The mRNA of TauT was evaluated by RT-PCR. Controls were included for each protocol. RESULTS: The transport of taurine, after 1 week of treatment, was significantly augmented compared to controls. The affinity significantly increased at 1 and 2 weeks. While the percentage of CD4+ cells decreased and that of CD8+ cells increased, the percentage of TauT in CD4+ and CD8+ cells was not affected. Reduction of levels of aspartic acid, glutamic acid, threonine, alanine, glycine, and arginine occurred at 1 and 2 weeks. The taurine concentration significantly decreased after 2 and 3 weeks of treatment. The estimation of mRNA of TauT was not different. CONCLUSION: Taurine transport increases with fluoxetine treatment, and so this could be related to an immunomodulatory role of fluoxetine through TauT. Inhibition of serotonin reuptake might be involved in the regulation of taurine transport in mononuclear cells.

Role of 5-HT2 and 5-HT7 Serotonin Receptors, and Protein Kinases C and A on Taurine Transport in Lymphocytes of Rats Treated with Fluoxetine.

Fluoxetine, an antidepressant and selective serotonin reuptake inhibitor, modulates immune cells in vitro. The present study investigates the influence of pharmacological agents which acts as agonist and antagonist of serotonin receptors ex vivo over taurine transport in lymphocytes of rats treated with fluoxetine by one week. The treatment with fluoxetine increase taurine transport and the incubation with the agonist of 5-HT2 receptor, 1-(2,5-dimethoxy-4-iodophenyl)-​2-aminopropane (DOI) counteract this effect, and ketanserin provoked no change in fluoxetine effect. While the agonist of 5-HT7 receptor, 4-[2-(methylthio)phenyl]-N-(1,2,3,4-tetrahydro-1-naphth alenyl)-1-piperazinehexanamide hydrochloride (LP44) had no significant effects, however the differences between Control and Fluoxetine groups were not observed, the antagonist (R)-3-[2-[2-(4-methylpiperidin-1-yl)ethyl]pyrrolidine-1-sulfonyl]phenol hydrochloride (SB269970) had no differences. Preincubation of cells with the diacylglycerol analogue, 1-oleoyl-2-acetyl-sn-glycerol (OAG) caused inhibition of fluoxetine treatment effect but this not occurred in presence of the PKC inhibitor, 1-O-hexadecyl-2-O-methyl-rac-glycerol (AMG-C16). Forskolin counteracted the effect of fluoxetine on taurine transport, since at the concentrations used, the rate of taurine transport in Fluoxetine group, returned to Control rate. No significant differences were observed with the PKA inhibitor. Although it is not possible to attribute a definitive role of 5-HT2 receptors in fluoxetine effect on taurine transport, its signaling might affect the function of it. Participation of PKC and PKA have an apparently relevant role in lymphocyte taurine transport.

Effect of Extracellular Zinc Chelator on Rat Retinal Ganglion Cell Number, and Taurine and Zinc Transporters in These Cells / Efecto de un quelante de zinc extracelular sobre el número de células ganglionares en retina de rata, y transportadores de taurina y de zinc en estas células

RESUMEN La deficiencia de zinc en humanos produce disminución de antioxidantes, asociados a taurina, en la retina y se relaciona con adaptación anormal a la oscuridad, cataratas, ceguera y degeneración macular. Existe escasa evidencia acerca del efecto del zinc sobre el sistema de taurina en retina de mamíferos, por lo cual estudiamos el efecto del zinc sobre el transportador de taurina (TAUT) y los transportadores de zinc (ZnT-1 y 3) usando el quelante de zinc extracelular, ácido dietileno-triamino-penta-acético (DTPA), mediante inmunocitoquímica e inmunohistoquímica fluorescentes en células ganglionares (CG) y en las capas de la retina de ratas. Tres días después de la administración de DTPA (10μM) se utilizaron anticuerpos primarios y secundarios conjugados con rodamina o fluoresceína-5-isotiocianato (FITC) según fuera el caso. Para el marcaje inmunocitoquímico se contaron trescientas células por condición y la intensidad de fluorescencia se midió como densidad óptica integrada (DOI) en cuatro áreas por cada capa del tejido. El DTPA produjo una disminución en un 32 % y 29 % de las CG del total de células marcadas con los anticuerpos contra glicoproteína Thy 1.1 y γ-sinucleína, respectivamente. También produjo una disminución significativa de la distribución de TAUT en un 27 y 28 % respecto a los controles. DTPA disminuyó la localización de ZnT-1 y ZnT-3 en las capas de retina (células ganglionares, CCG y en las plexiformes externa e interna, CPE y CPI). El estudio de estos transportadores en la retina resulta relevante para entender las interacciones de taurina y de zinc en esta estructura.

ABSTRACT Zinc deficiency in humans causes decreased antioxidants in the retina and is related with abnormal darkness adaptation, cataracts, blindness, and macular degeneration. There is little information about the effects of zinc on the taurine system in mammalian retinal cells. Therefore, we studied the effect of zinc on the taurine transporter (TAUT) and zinc transporters (ZnT-1 and 3) using the extracellular zinc chelator, diethylenetriaminepentaacetic acid (DTPA) by fluorescence immunocytochemistry and immunohistochemistry in the ganglion cells (CG) and cell layers of the retina of rats. Three days after administration ofDTPA (10μM) primary antibodies and secondary antibodies conjugated with rhodamine or fluorescein isothiocyanate (FITC) were used as required. For immunocytochemical labeling approximately three hundred cells per condition were counted. For immunohistochemical labeling, the fluorescence intensity was measured as integrated optical density (DOI) in four areas for each layer of tissue. DTPA produced a decrease of 32 % and 29 % in GC of the total cells labeled with antibody against glycoprotein Thy 1.1 and γ-synuclein, respectively. It also produced a significant decrease in TAUT localization in 27 and 28 % compared to controls. DTPA produced a decrease in the localization of ZnT-1 and ZnT-3 in the retina layers (ganglion cells, GCC and the outer and inner plexiform, CEP and CIP). The study of these molecules in the retina is relevant to understanding the interactions of taurine and zinc in this structure.

Zinc and zinc chelators modify taurine transport in rat retinal cells.

Zinc regulates Na(+)/Cl(-)-dependent transporters, similar to taurine one, such as those for dopamine, serotonin and norepinephrine. This study examined the ex vivo effect of zinc (ZnSO4), N,N,N,N-tetraquis-(2-piridilmetil)etilendiamino (TPEN) and diethylenetriaminepenta-acetic acid (DTPA), intracellular and extracellular zinc chelators, respectively, on rat retina [(3)H]taurine transport. Isolated cells were incubated in Locke solution with 100 nM of [(3)H]taurine for 25 s. Different concentrations of ZnSO4 (0.5-200 µM) were used. Low concentrations of ZnSO4 (30 and 40 µM) increased the transport, while higher concentrations (100, 150 and 200 µM) decreased it. Various concentrations of TPEN (1-200 µM) were added. Intermediate concentrations of TPEN (10-60 µM) significantly decreased [(3)H]taurine transport. The presence of TPEN, 20 µM, plus ZnSO4 reversed the effect of TPEN alone. Several concentrations of DTPA (1-500 µM) were also investigated. Reduction of transport took place at high concentrations of the chelator (100, 250 and 500 µM). DTPA, 500 µM, plus ZnSO4, did not modify the effect of it. These results indicate that zinc modulates taurine transport in a concentration-dependent manner, directly acting on the transporter or by forming taurine-zinc complexes in cell membranes.

5-HT7 receptors and tryptophan hydroxylase in lymphocytes of rats: mitogen activation, physical restraint or treatment with reserpine.

OBJECTIVES: Serotonin (5-HT)7 receptors in lymphocytes play a relevant role as modulators of T cell functions and might be modified by stress protocols. The aims of this work were to evaluate: (i) the presence of 5-HT7 receptors in specific lymphocyte populations, (ii) the probable modifications of them by inflammatory stress with mitogen and (iii) the effects of physical and pharmacological stress. METHODS: Blood lymphocytes were isolated by density gradients and differential adhesion to plastic. Concanavalin A (Con A) was systemically administered (500 µg/kg) or added to lymphocyte cultures (2.5 µg/ml, final volume 200 µl). Physical restraint was performed in Plexiglass boxes for 5 h per day for 5 days. Reserpine administration was 2.5 mg/kg for 3 days. Immunocytochemical labeling of CD4+, CD8+ and 5-HT7 receptors, and also tryptophan hydroxylase cells was performed. mRNA of 5-HT7 receptors was evaluated by RT-PCR. Controls were included for each protocol. RESULTS: Con A treatment or culture exposure increased the number of lymphocytes expressing 5-HT7 receptors or tryptophan hydroxylase, as compared to absence of the mitogen. Receptors were present in 12-16% of total rat lymphocytes, in ∼10% of CD4+ and in ∼5% of CD8+ cells from control rats. CD4+ decreased, and CD8+ and 5-HT7 cells increased after physical restraint. Reserpine treatment elevated CD8+ and 5-HT7 cells. Con A and physical restraint, but not reserpine treatment, significantly augmented 5-HT7 receptor mRNA in lymphocytes. CONCLUSIONS: Rat lymphocytes, expressing tryptophan hydroxylase, could synthesize 5-HT, functioning as a direct autocrine modulator. The modifications of CD4+, CD8+ and 5-HT7 receptors in lymphocytes by three stress protocols could have an impact on immune responses. In addition, the differential distribution of 5-HT7 receptors indicates potential specific physiopathological roles.

Serotonin transporter in lymphocytes of rats exposed to physical restraint stress.

OBJECTIVES: Glucocorticoids and stress cause transcriptional and functional changes on the serotonin transporter (SERT) in the central nervous system. Stress can produce specific modifications of SERT in lymphocytes, which could be associated with alterations in immune response. The aim of this study was to evaluate the effect of a physical restraint stress protocol on (1) rat lymphocyte proliferation in the presence of the selective serotonin reuptake inhibitor fluoxetine and (2) SERT kinetic parameters, i.e. binding capacity (Bmax), affinity (Kd) and Hill coefficient (nH). METHODS: Male adult Sprague-Dawley rats were placed in Plexiglass boxes (5 h daily for 5 days), and blood was obtained by cardiac puncture on day 6. Serum corticosterone was quantitated by an immunoenzymatic assay. Lymphocytes were isolated by density gradients and adhesion to plastic, of which there was sufficient material for further experiments, then cultured with or without the mitogen concanavalin A (Con A, 2 µg/ml) and fluoxetine (1-50 µM). Cell proliferation was measured with tetrazolium salts, and [(3)H]paroxetine was used as a SERT-specific ligand for binding assays. RESULTS: Restraint produced a significant increase in serum corticosterone of stressed rats. The proliferative response to Con A was similar in the controls and stressed animals. Fluoxetine reduced cell proliferation with and without Con A. Restraint diminished the inhibitory effect of fluoxetine on proliferation. Restraint also increased Bmax and Kd, but decreased nH. Treatment of rats with actinomycin D, a transcription inhibitor, reduced Bmax in stressed animals. CONCLUSIONS: Restraint stress modulated the effect of fluoxetine on cell proliferation, probably through the modification of the presence and the function of SERT.

Neurites outgrowth and amino acids levels in goldfish retina under hypo-osmotic or hyper-osmotic conditions.

Amino acids are known to play relevant roles as osmolytes in various tissues, including the retina. Taurine is one of these active molecules. In addition, taurine stimulates outgrowth from the goldfish retina by mechanisms that include extracellular matrix, calcium fluxes and protein phosphorylation. The present report aims to explore the effect of medium osmolarity on goldfish retinal outgrowth and the possible modifications produced by changing eye osmolarity on amino acid levels in the retina. Goldfish retinal explants were obtained 10 days after crush of the optic nerve and cultured under iso-, hypo- or hyper-osmotic conditions. Hypo-osmotic medium was prepared by diluting the solutions 10% twice, preserving fetal calf serum concentration. Hyper-osmotic medium was done by adding 50 or 100 mM urea or mannitol. Evaluation of length and density of neurites was performed 5 days after plating. Outgrowth was reduced in hypo- and in hyper-osmotic conditions. Taurine, 4 mM, increased length and density of neurites in iso-osmotic, and produced stimulatory effects under both hyper-osmotic conditions. The in vivo modification of osmolarity by intraocular injection of water or 100 mM urea modified levels of free amino acids in the retina. Taurine and aspartate retinal levels increased in a time-dependent manner after hypo- and hyper-osmotic solution injections. Serine, threonine, arginine, γ-aminobutyric acid, alanine and tyrosine were elevated in hyper-osmotic conditions. Outgrowth in vitro, after in vivo osmolarity changes, was higher in the absence of taurine, but did not increase in the presence of the amino acid. The fact that certain outgrowth took place in these conditions support that the impairment was not due to tissue damage. Rather, the effects might be related to the cascade of kinase events described during osmolarity variations. The time course under these conditions produced adjustments in ganglion cells probably related to taurine transporter, and phosphorylation of specific proteins.

Efecto de la restricción física: sobre el papel de los receptores 5-HT1A en la proliferación linfocitaria / Effect of phisical restraints: the role of the 5-HT1A in lymphocyte proliferation

El estrés afecta el sistema inmunológico, sin embargo, no hay reportes sobre receptores de serotonina en linfocitos. Se estudiaron los receptores 5-HT1A y la proliferación linfocitaria de ratas macho adultas luego de restricción física. Fueron colocadas en cajas de Plexiglass durante 5 horas diarias por 1, 3 ó 5 días. Se extrajo sangre cardíaca, se aislaron los linfocitos por gradiente de densidades y adhesión al plástico; se cultivaron con el agonista 8-hidroxi-di-n-propil-aminotetralina(8-OH-DPAT) ó el antagonista N-(2-(4-(2-metoxifenil)-1-piperazinetil)-N-(2-piridinil) ciclohexanocarboxamida (WAY-100635) de los receptores 5-HT1A y del mitógeno concanavalina A. La proliferación se midió con sales de tetrazolio. La 8-OH-DPAT no afectó la proliferación. El WAY-100635 disminuyó la proliferación. La restricción física aumentó la sensibilidad al efecto del WAY-100635, lo cual podría deberse a cambios en la expresión o a una modulación funcional de los receptores por efecto del estrés, como se ha reportado previamente en cerebro de rata.

Stress affects the immune system, however, little is known about the effects on specific modifications of lymphocytes serotonin receptors. The effects of restraint stress on the role of 5-HT1A receptors in lymphocyte proliferation were evaluated in male adult rats. They were placed in Plexiglass boxes, during 5 daily hours for 1, 3 or 5 consecutive days. Next day a blood sample was obtained by cardiac punction. Lymphocytes were isolated by density gradient and adhesionto plastic. They were cultured with agonist 8-hydroxy-di-n-propyl-aminotetralin (8-OH-DPAT) or antagonist N-(2-(4-(2-methoxyphenyl)-1-piperazinyl) ethyl)-N-(2-pyridiyl) cyclohexanecarboxamide (WAY-100635) of 5-HT1A receptors and the mitogen concanavalin A. Proliferation was measured by tetrazolium salts. 8-OH-DPAT did not modify cell proliferation; WAY-100635 diminished it. Restraint stress increased the susceptibility to effect of WAY-100635. These results suggest changes in the expression or functional modulation of 5-HT1A receptors in lymphocytes by stress, similar to previous reports on serotonergic system in rat brain.

Ácidos grasos omega-3 como coadyuvantes del tratamiento antidepresivo y sus efectos sobre el factor neurotrófico derivado del cerebro en suero y en células mononucleares / Omega-3 fatty acids as adjunctive of antidpressant therapy and its effects on brain-derived neurotrophic factor in serum, monocytes and lymphocytes

El estrés disminuye el factor neurotrófico derivado del cerebro (BDNF) en el hipocampo; los antidepresivos y los ácidos grasos omega-3 podrían aumentarlo. En pacientes con depresión mayor, investigamos la respuesta clínica a un antidepresivo solo o con ácido eicosapentanoico (EPA), y su influencia sobre los niveles de BDNF. Veinte pacientes se diagnósticaron según el DSM-IV-TR; evaluamos la respuesta con la Escala de Hamilton para Depresión (HAM-D). Los controles fueron 15 sujetos sanos. Los pacientes se distribuyeron en 2 grupos: uno recibió fluoxetina 20 mg/día y EPA 3.000 mg/día, y otro con fuoxetina 20 mg/día y placebo, durante 8 semanas. Se tomaron muestras de sangre en las semanas 0 y 8 para obtener suero, sin anticuoagulante, para medir los niveles de BDNF, y para aislamiento de células mononucleares, con heparina, para la localización inmunocitoquímica de BDNF. Diez pacientes no continuaron por diferentes causas. De los 10 restantes, 5 recibieron EPA y 5, placebo. El BDNF sérico disminuyó despúes de tratamiento en ambos grupos, más evidente en el grupo con EPA en el análisis pareado. El porcentaje de células mononucleares que expresaron BDNF fue inferior en los pacientes y aumentó después de los tratamientos. Por otra parte, las células con BDNF, las cuales estaban bajas en los deprimidos, aumentaron después de los tratamientos, lo que indica que en estás, el papel del tratamiento, especialmente con la combinación del antidepresivo y el ácido en cuestión, las modificaciones en el BDNF son más evidentes. A pesar de la limitante que constituye la inclusión de los sujetos diagnósticados, más la permanencia de los incluidos, los resultados significativos señalan un efecto beneficiosos del uso de EPA en la depresión mayor

Stress is associated with a decreased expression of brainderived neurotrophic factor (BDNF) in the hippocampus. Antidepressants and omega-3 fatty acids might increase circulating BDNF. This research was done to evaluate, in major depression patients, the possible differences in clinical response to an antidepressant alone or in combination with eicosapentaenoic acid (EPA), and their influence on BDNF levels. Nineteen patients were diagnosed according to DSM-IV-TR criteria; severity and response was evaluated by Hamilton Depression Rating Scale (HAM-D). Control group was composed of 15 healthy subjects. Patients were randomized on a double-blind bassis in two groups: one recived fluoxetine 20 mg/day and EPA 3,000 mg/day, and the other one fluoxetine 20 mg/day an placebo, during 8 weeks. Blood samples were taken for obtaining serum and for isolating monocytes and lymphocytes at weeks 0 and 8. Ten patients dropped out for different causes. Of the remaining 9 subjetcs, 4 recived EPA and 5 got placebo. The percentage of mononuclear cells expressing BDNF was lower in patients, and it was significantly increased after the treatments. EPA seems to augment the clinical response. In depressed, after treatment, there was a lower content of serum BDNF. Moreover, mononuclear cells with BDNF, which were lower in this group of depressed, increased after the treatments, indicating that in cells the modulation of BDNF by antidepressants is more evident

Effects of zinc ex vivo on taurine uptake in goldfish retinal cells.

BACKGROUND: Taurine and zinc exert neurotrophic effects in the central nervous system. Current studies demonstrate that Na+/Cl- dependent neurotransmitter transporters, similar to that of taurine, are modulated by micromolar concentrations of zinc. This study examined the effect of zinc sulfate ex vivo on [3H]taurine transport in goldfish retina. METHODS: Isolated cells were incubated in Ringer with zinc (0.1-100 microM). Taurine transport was done with 50 nM [3H]taurine or by isotopic dilution with taurine (0.001-1 mM) and 50 nM [3H]taurine. RESULTS: Zinc reduced the capacity of taurine transport without changes in affinity, and caused a noncompetitive inhibition of high affinity taurine transport, with an EC50= 0.072 microM. The mechanism by which zinc affects taurine transport is unknown at the present. CONCLUSIONS: There may be a binding site of zinc in the transporter that affects union or translocation of taurine, or possibly the formation of taurine-zinc complexes, rather than free zinc, could affect the operation of the transporter.

Taurine and proliferation of lymphocytes in physically restrained rats.

BACKGROUND: Taurine is present in lymphocytes and seems to modulate certain immune cell functions. Among the effects of taurine on these cells are protection against antioxidants and regulation of inflammatory aspects of the immune response. Stress affects antigen presentation, traffic and proliferation of leukocytes, as well as antibody and cytokine secretion. The purposes of this study were to explore the possible direct effects of taurine concentrations on lymphoproliferation and interleukins levels in control and in physical restrained rats. METHODS: Lymphocytes of male Sprague-Dawley rats, stressed by physical restrain and controls (5 h per day for 5 days) were isolated from blood by Histopaque (1077 g/l) and differential adhesion to plastic, and then cultured (72 h) in the presence of different concentrations of taurine (0.5-50 mM), beta-alanine (0.5-50 mM), or both, without or with the T cells mitogen, concanavalin A. Plasma and lymphocytes levels of pro-inflammatory interleukin-1beta and anti-inflammatory interleukin-10 were respectively measured by Pierce Endogen rat ELISA Kits. Taurine in plasma and in lymphocytes were determined by HPLC. RESULTS: Lymphoproliferation of resting cells significantly decreased in the presence of 3 and 6 mM taurine and increased up to control level at 12 mM taurine. In concanavalin A-activated lymphocytes, the effect of taurine was greater. beta-alanine increased lymphoproliferation in a bell shaped dose-dependent manner and decreased it in activated lymphocytes but in a lower magnitude. In combination, beta-alanine impaired the effect of taurine at 3 and 6 mM. After restriction, no change in lymphoproliferation was observed at different concentrations of the amino acids without or with concanavalin A, although pro-inflammatory interleukin and taurine in plasma and in lymphocytes significantly increased. CONCLUSIONS: Taurine affects lymphoproliferation in control rats, following a dose-dependent manner, an effect that might involve its transport into the cells. Elevation of interleukin-1beta produced in stressed rats by physical restrain could seriously affect the immune balance, whereas taurine increase might be protective. These results suggest that taurine and taurine transport play a role in lymphoproliferation. In addition, modifications of taurine system in lymphocytes take place during restriction stress.

Validez de la versión venezolana del cuestionario de trastornos del estado de ánimo (MDQ) para detectar al trastorno bipolar tipo II en pacientes con depresión mayor / Validation of the spanish version of the mood disorder questionnaire to detect bipolar disorder type II in patients with major depression disorder

El Cuestionario de Trastornos del Estado de Ánimo (MDQ) ha sido validado en varios países para pesquisar al trastorno bipolar tipo II (TB II). Por esta razón los autores nos propusimos determinar la validez de criterio del MDQ -versión venezolana- en pacientes con el diagnóstico previo de trastorno depresivo mayor, episodio único o recurrente. Mediante un estudio realizado en dos etapas, fueron evaluados 199 pacientes provenientes de la Consulta Externa de Psiquiatría del Hospital Vargas de Caracas, Venezuela. Inicialmente fueron sometidos a una evaluación diagnóstica guiada por la Entrevista Clínica Estructurada para los Trastornos del Eje I del DSM-IV (SCID-I) y, posteriormente, se les pidió que contestaran el MDQ con un punto de corte 7/13. El protocolo fue aprobado por el comité de ética de la institución. La mayoría de los pacientes pertenecían al sexo femenino (78,4%). La edad media de las mujeres fue de 43,94 años (DE = 12,06) y la de los hombres fue de 43,60 años (DE = 14,19). La frecuencia de falsos unipolares fue de 28,1% (23,6% trastorno bipolar tipo I y 4,5 por ciento TB II). Al asociar los resultados obtenidos mediante la SCID-I y el MDQ, se encontró una sensibilidad de 100% (95% IC: 0,66-1,00) y una especificidad de 61,1% (95% IC: 0,53-0,68) para el diagnóstico de TB II. Sobre la base de los índices de validez obtenidos, los autores concluimos que el MDQ, con un punto de corte 7/13, es un instrumento válido para detectar al TB II en una consulta de psiquiatría general venezolana.

The Mood Disorder Questionnaire (MDQ) is an inventory used to detect bipolar disorder type II (BD II) and it has been validated in several countries, other than Venezuela. For this reason, the authors tried to determine the criterion validity of the Venezuelan version of the MDQ in Venezuelan patients. The study was carried out in two stages at the Psychiatric Department of the Hospital Vargas of Caracas, Venezuela, which is a general teaching hospital. A group of 199 adult outpatients, who had been previously diagnosed as suffering from major depression disorder -single episode or recurrent- were evaluated. Initially, they were diagnosed using the Structured Clinical Interview for DSM-IV for Axis I Disorders (SCID-I). Afterwards, they were asked to answer the MDQ using a cut-off point 7/13. The protocol was approved by the institutional review board of the Hospital Vargas of Caracas. A total of 78.4% of the subjects were female. The mean age was 43.60 years for males (SD = 14.19) and 43.94 years for females (SD = 12.06). The frequency of false unipolar patients was 28.1% (23.6% bipolar disorder type I and 4.5% BD II). While comparing the results of the SCID-I and the MDQ, a sensibility of 100.0% (95% CI: 0.66-1.00) and a specificity of 61.1% (95% CI: 0.53-0.68) were found for the diagnosis of BD II. According to our results, the MDQ with a cut-off point 7/13 is a valid instrument to detect the bipolar disorder type II in Venezuelan depressed outpatients.

Fluoxetine treatment to rats modifies serotonin transporter and cAMP in lymphocytes, CD4+ and CD8+ subpopulations and interleukins 2 and 4.

Several lines of evidences indicate that antidepressants produce various immunomodulatory effects. Fluoxetine, an antidepressant and selective serotonin reuptake inhibitor, modulates immune cells in vitro. To explore the in vivo influence of fluoxetine on lymphocytes, male Sprague-Dawley rats were treated daily, 10 mg/kg, or with saline solution for 1, 2 and 3 weeks. The presence of serotonin transporter in CD3+, CD4+ and CD8+ subpopulations of T lymphocytes was determined by immunofluorescence. Serotonin transporter was also labeled with [(3)H]paroxetine, specific binding defined with imipramine. Plasma levels of pro-inflammatory interleukin 2 (IL-2), and anti-inflammatory interleukin 4 (IL-4), were measured by ELISA; and cAMP concentration by radioimmunoassay. Fluoxetine significantly increased the number of lymphocytes expressing serotonin transporter and elevated the binding of [(3)H]paroxetine. The percentage of CD4+ cells decreased, that of CD8+ increased, and CD3+ did not change. The ratio CD4+/CD8+ was significantly lowered. Fluoxetine administration elevated the levels of IL-4 at 1, 2 and 3 weeks; and of IL-2, at 2 and 3 weeks. IL-4/IL-2 ratio was significantly increased in fluoxetine group respecting the controls and was similar during the 3 weeks of treatment. Fluoxetine produced a significant decrease in cAMP concentrations in lymphocytes, probably by secondary activation of serotonin receptors. Treatment with fluoxetine modified immune parameters in plasma and lymphocytes of rats, which might be relevant for its systemic therapeutic action as an antidepressant.

Taurine transporter in lymphocytes of patients with major depression treated with venlafaxine plus psychotherapy.

The taurine transporter and taurine are present in lymphocytes, where taurine functions as an antioxidant and an anti-inflammatory agent. Taurine levels are elevated in lymphocytes of subjects with major depression, but returns to control levels after treatment with the antidepressant mirtazapine. Patients (40) were diagnosed using the Diagnostic and Statistical Manual IV of the American Psychiatric Association, and the severity of their condition was determined by the Hamilton Scale of Depression. One group of patients was treated with venlafaxine and the other with venlafaxine plus Neuro-Linguistic Programming. Lymphocytes were isolated from the peripheral blood by Ficoll/Hypaque. The coexistence of the taurine transporter with a subpopulation of CD4+ and CD8+ lymphocytes was measured by immunofluorescence. The levels of the pro-inflammatory, IL-2, and the anti-inflammatory, IL-4, cytokines were determined by ELISA while plasma amino acid levels were determined by HPLC. The percentage of CD4+ cells significantly decreased after both treatments, whereas the levels of CD8+ cells remained unchanged. The taurine transporter of CD4+ and CD8+ cells decreased after integrate treatment. No differences were found in the levels of IL-2 while IL-4 levels increased after integrate treatment. The observed effects of treatment on the taurine transporter and IL-4 content might modify lymphocyte activity during depression.

Effect of medium osmolarity and taurine on neuritic outgrowth from goldfish retinal explants.

Taurine stimulates outgrowth of goldfish retinal explants in a concentration- and time-dependent manner, an effect related to calcium movement and protein phosphorylation. Since taurine is an osmoregulator in the central nervous system, and osmolality might influence regeneration, the purpose of this work was to evaluate the possible effect of hypo-osmolality on basal outgrowth and on the trophic action of the amino acid. Accordingly, goldfish retinal explants obtained after crushing the optic nerve were cultured in iso- and hypo-osmotic medium, the latter achieved by diluting the medium 10% 24 and 72 h after plating. The length and density of the neurites, measured after 5 days in culture, were significantly lower in the hypo- than in the iso-osmotic medium. Taurine stimulated the outgrowth under both conditions, but the percentage of increase was greater in iso-osmotic medium. Taurine concentration, determined by HPLC, did not significantly change in explants. Co-administration of beta-alanine and taurine impaired the trophic effect of taurine to a greater extent in the iso- than in hypo-osmotic medium, indicating a possible differential interaction with the taurine transporter which could be altered by osmotic stress. The exact mechanism of outgrowth regulation by hypotonicity requires further clarification, taking into considering possible modification of the taurine transporter.

Localization of taurine transporter, taurine, and zinc in goldfish retina.

Taurine and zinc interact during structural and functional development of the rat retina and during the process of regeneration of retinal fragments from goldfish. These observations formed the basis for evaluating the regional correlation between the localization of the taurine transporter, taurine content and labile zinc content in goldfish retina. In the retina, the taurine transporter is expressed in photoreceptors, the outer plexiform layer, the inner nuclear layer and the ganglion cell layer. Taurine was detected in photoreceptors, the outer and inner nuclear layers, the outer plexiform layer and the ganglion cell layer. A large amount of labile zinc was detected in photoreceptors and to a lesser extent in ganglion cells. The taurine transporter, taurine and zinc coexist in photoreceptors and the ganglion cell layer. Their co-localization in photoreceptors may be related to the neuro-protective role of taurine and zinc in this layer. By contrast, their co-existence in ganglion cells may be related to their involvement in cell differentiation, development, and regeneration. This reveals the importance of taurine and zinc in maintaining normal cellular function in these particular layers of the retina.

Effect of folic acid combined with fluoxetine in patients with major depression on plasma homocysteine and vitamin B12, and serotonin levels in lymphocytes.

OBJECTIVE(S): Folic acid, a micronutrient supporting the natural defense system, may elevate antidepressant responses, although the lymphocyte serotonergic system has not been explored in folate-supplemented depressed patients. METHODS: Twenty-seven patients were randomly assigned to groups receiving fluoxetine (20 mg) and folic acid (10 mg/day) or fluoxetine and placebo for 6 weeks. Clinical outcome was assessed according to the Hamilton Depression Rating Scale (HDRS) at the beginning, during and at the end of treatment. Blood samples were taken, plasma was separated, and lymphocytes were obtained by density gradient centrifugation with Ficoll/Hypaque and differential adhesion to plastic dishes. Fifteen healthy subjects served as controls. Plasma folate, homocysteine and vitamin B12, and serotonin concentration in lymphocytes were determined by HPLC. The HDRS score was significantly lower in patients receiving fluoxetine and folic acid compared with those receiving fluoxetine and placebo after 6 weeks of treatment (7.43 +/- 1.65 vs. 11.43 +/- 1.31, respectively; p = 0.04). Plasma homocysteine statistically significant decreased after folic acid (p = 0.02), but no significant changes were observed in vitamin B12. RESULTS: Serotonin was significantly reduced after fluoxetine either with folate (p = 0.03) or placebo (p = 0.01) probably by the effect of transporter blockade. 5-Hydroxyindoleacetic acid was lower in lymphocytes of patients receiving folate (p = 0.04), indicating a reduced turnover rate, thus accumulating serotonin in the cells. A significant negative correlation was noted between homocysteine and folate. No significant correlations were present among biochemical parameters and depression severity. CONCLUSION: Modifications due to treatment with fluoxetine and folic acid may alter lymphocyte function in depression probably indirectly by reducing homocysteine levels and directly on lymphocytes by modifying the serotonergic system.

Serotonin transporter is differentially localized in subpopulations of lymphocytes of major depression patients. Effect of fluoxetine on proliferation.

Modifications of lymphocyte serotonergic system have been described in major depression. The aim of this study was to determine new possible changes of this system in depression. Twenty eight patients, free of drugs, diagnosed with major depression disorder by Structured Clinical Interview for Disorders of Axis I, without medical illnesses, written consent, approved by Ethical Committees were included. Controls were 30 healthy subjects without family history of psychiatric disease. Blood monocytes were isolated with Ficoll/Hypaque, and lymphocytes by differential adhesion to plastic. Serotonin and 5-hydroxyindoleacetic acid determined by HPLC. Monocytes had higher serotonin concentrations than lymphocytes, and serotonin/5-hydroxyindoleacetic acid was lower in patients. Basal proliferation was elevated in depressed and not increased by Concanavalin A. Fluoxetine reduced basal proliferation more efficiently in patients, indicating activation of lymphocytes in depression. The number of cells expressing serotonin transporter was reduced in depressed. There were no differences in CD4+ (approximately 50%) or CD8+ (approximately 25%) lymphocytes between the groups, although CD8+ were lower in depressed, and greater number of them co-localized serotonin transporter than CD4+, which could be crucial for function in relation to serotonin and its receptors in immune cells. Lymphocytes were activated in this group of patients and fluoxetine reduced proliferation, probably being relevant for the psychopharmacological treatment of depression.

Síntesis de serotonina y presencia de hidroxilasa de triptófano en linfocitos de pacientes con depresión mayor tratados con fluoxetina y ácido fólico / Synthesis of serotonin and tryptophan hydroxylase in lymphocytes from patients with major depression treated with fluoxetine and folic acid

El ácido fólico ha sido utilizado como coadyuvante antidepresivo, y se han reportado bajos niveles séricos en deprimidos. Debido al papel del ácido fólico y a la relevancia del sistema serotonérgico linfocitario en la depresión, el objetivo de este estudio es determinar la capacidad de producción de serotonina y la presencia de la hidroxilasa del triptófano en linfocitos de pacientes deprimidos tratados con fluoxetina y ácido fólico. Los pacientes fueron diagnosticados con los criterios del Manual Diagnóstico y Estadístico de la Asociación Psiquiátrica Americana, la intensidad del episodio depresivo se determinó mediante la Escala de Hamilton para Depresión. Veintisiete pacientes (21-58 años) fueron seleccionados, no presentaban otra patología ni riesgo suicida. Se distribuyeron en forma aleatoria en dos grupos experimentales, unos (14) recibieron fluoxetina, 20 mg/d, más ácido fólico, 10 mg/d y otros (13) fluoxetina más placebo. El grupo control fue constituido por 15 sujetos aparentemente sanos (26-49 años). Se tomaron muestras de sangre al principio y después de seis semanas. Diez pacientes de cada grupo experimental culminaron el estudio. La homocisteína plasmática disminuyó con la administración de ácido fólico. Los linfocitos fueron aislados por gradientes de densidades con Ficoll/Hypaque y adhesión diferencial al plástico. Las concentraciones de serotonina en linfocitos se determinaron por cromatografía líquida de alta resolución con detector electroquímico y no difirieron entre los dos grupos ni en relación al control, pero fueron bajas en los que recibieron el tratamiento. La síntesis de serotonina a partir de triptófano fue menor en los pacientes en relación a controles, y disminuyó después de los dos tratamientos. El número de linfocitos con la enzima fue menor en los pacientes y decreció después del ácido fólico.