Syphilis, human immunodeficiency virus, herpes genital and hepatitis B in a women's prison in Cochabamba, Bolivia: prevalence and risk factors.

OBJECTIVE: To determine the prevalence and factors associated with syphilis, human immunodeficiency virus (HIV), hepatitis B (HBV) and herpes type 2 (HSV2) among women in the prison of San Sebastian in Cochabamba (Bolivia). MATERIAL AND METHODS: We carried out a cross-sectional study including a standardized questionnaire to assess socio-demographics characteristics and risk factors (sexual practices and exposure to blood); and serological tests for syphilis, HSV2, VIH, and HBV. We performed bivariate and multivariate analyses to test the associations between variables of interest and infections. RESULTS: A total of 219 out of 220 prisoners (99.5%) participated in the study. For syphilis, 12.8% of participants had both reactive tests (RPR+/TPPA+). The prevalence of HSV2 and VIH was 62.6% and 1.4%, respectively. Anti-HBc, indicating a resolved or chronic HBV, was positive in 11.9% of participants and 0.5% had active HBV (HBsAg positive). A low level of education was associated with syphilis, HSV2 and HBV. Having occasional sexual partners was associated with syphilis and HSV2. Being over 36 years old and having more than 3 children were associated with HBV. The number of sexual partners, history of prostitution and rape, having sexual intercourses in prison and detention time were not associated with any of these infections. DISCUSSION: The prevalence of syphilis, HIV, HSV2 and HBV was higher in this vulnerable female population than in the general population in Bolivia. Control measures in detention are needed to limit the spread of these infections both in prisons and in the community.

Oral myeloid cells uptake allergoids coupled to mannan driving Th1/Treg responses upon sublingual delivery in mice.

BACKGROUND: Polymerized allergoids coupled to nonoxidized mannan (PM-allergoids) may represent novel vaccines targeting dendritic cells (DCs). PM-allergoids are better captured by DCs than native allergens and favor Th1/Treg cell responses upon subcutaneous injection. Herein we have studied in mice the in vivo immunogenicity of PM-allergoids administered sublingually in comparison with native allergens. METHODS: Three immunization protocols (4-8 weeks long) were used in Balb/c mice. Serum antibody levels were tested by ELISA. Cell responses (proliferation, cytokines, and Tregs) were assayed by flow cytometry in spleen and lymph nodes (LNs). Allergen uptake was measured by flow cytometry in myeloid sublingual cells. RESULTS: A quick antibody response and higher IgG2a/IgE ratio were observed with PM-allergoids. Moreover, stronger specific proliferative responses were seen in both submandibular LNs and spleen cells assayed in vitro. This was accompanied by a higher IFNγ/IL-4 ratio with a quick IL-10 production by submandibular LN cells. An increase in CD4+ CD25high FOXP3+ Treg cells was detected in LNs and spleen of mice treated with PM-allergoids. These allergoids were better captured than native allergens by antigen-presenting (CD45+ MHC-II+ ) cells obtained from the sublingual mucosa, including DCs (CD11b+ ) and macrophages (CD64+ ). Importantly, all the differential effects induced by PM-allergoids were abolished when using oxidized instead of nonoxidized PM-allergoids. CONCLUSION: Our results demonstrate for the first time that PM-allergoids administered through the sublingual route promote the generation of Th1 and FOXP3+ Treg cells in a greater extent than native allergens by mechanisms that might well involve their better uptake by oral antigen-presenting cells.

Rapid diagnostic testing to improve access to screening for syphilis in prison.

OBJECTIVES: To assess the accuracy of on-site rapid treponemal test for syphilis diagnosis in women deprived of liberty in Bolivia. MATERIAL AND METHODS: Serological tests for syphilis were performed on 219 women deprived of liberty from the San Sebastián prison in Cochabamba, Bolivia. Syphilis was diagnosed using RPR (bioMérieux) and TPPA (Fujirebio) serological tests, and the results were compared to on-site rapid treponemal test (Alere DetermineTM Syphilis TP) in whole blood. Diagnostic performance of two FTA tests were also compared (bioMérieux and Biocientífica). RESULTS: All participants (28) with RPR+/TPPA+ had the rapid syphilis test positive (sensitivity 100%). Eleven participants had rapid syphilis test positive without RPR and TPPA both positive; nevertheless 7 of them had RPR or TPPA positive. Of 33 participants with FTA-bioMérieux positive, 22 (66.6%) had FTA-Biocientífica positive. DISCUSSION: The rapid syphilis test Determine shows excellent performance as a screening tool among women deprived of liberty affected by high prevalence of syphilis. This test is particularly indicated when there are barriers for access to conventional serological tests. It is inexpensive, easy to use and does not require electricity and laboratory infrastructure. The FTA test performed with reagents from Biocientífica had a suboptimal sensitivity.

Sífilis, virus de la inmunodeficiencia humana, herpes tipo 2 y hepatitis B en una prisión de mujeres en Cochabamba, Bolivia: prevalencia y factores de riesgo / Syphilis, human immunodeficiency virus, herpes genital and hepatitis B in a women's prison in Cochabamba, Bolivia: prevalence and risk factors

Objetivo: Determinar la prevalencia y los factores asociados a la infección por sífilis, virus de la inmunodeficiencia humana (VIH), virus de hepatitis B (VHB) y virus herpes tipo 2 (HSV2) en las mujeres privadas de libertad (MPL) en la prisión de San Sebastián en Cochabamba (Bolivia). Material y método: Se realizó un estudio transversal. Mediante un cuestionario estandarizado se registraron las características sociodemográficas, las prácticas sexuales y la existencia de exposición a la sangre. Se realizaron pruebas serológicas para sífilis, HSV2, VIH y VHB. Para conocer la asociación entre las variables de interés y las enfermedades, se llevaron a cabo análisis bi y multivariantes. Resultados: Participaron 219 de 220 MPL (99,5%). La prevalencia de sífilis (RPR+/TPPA+), HSV2, VIH y VHB crónico (ABsAg+) fue de 12,8%, 62,6%, 1,4% y 0,5%, respectivamente. La sífilis y el HSV2 se asociaron con un bajo nivel de educación y con el hecho de tener parejas sexuales ocasionales. El VHB se asoció con un bajo nivel de educación, la edad y el hecho de tener más de tres hijos. Estas infecciones no se asociaron con el número de parejas sexuales, los antecedentes de prostitución o violación, las relaciones sexuales en prisión y la duración de la pena privativa de libertad. Discusión: La prevalencia de las enfermedades investigadas (sífilis, VIH, HSV2 y VHB) es más elevada en la población penitenciaria femenina que en la población general de Bolivia. Es necesario implementar medidas de control en la prisión para limitar la propagación de estas infecciones, tanto en prisiones como en la comunidad

Objective: To determine the prevalence and factors associated with syphilis, human immunodeficiency virus (HIV), hepatitis B (HBV) and herpes type 2 (HSV2) among women in the prison of San Sebastian in Cochabamba (Bolivia). Material and methods: We carried out a cross-sectional study including a standardized questionnaire to assess socio-demographics characteristics and risk factors (sexual practices and exposure to blood); and serological tests for syphilis, HSV2, VIH, and HBV. We performed bivariate and multivariate analyses to test the associations between variables of interest and infections. Results: A total of 219 out of 220 prisoners (99.5%) participated in the study. For syphilis, 12.8% of participants had both reactive tests (RPR+/TPPA+). The prevalence of HSV2 and VIH was 62.6% and 1.4%, respectively. Anti-HBc, indicating a resolved or chronic HBV, was positive in 11.9% of participants and 0.5% had active HBV (HBsAg positive). A low level of education was associated with syphilis, HSV2 and HBV. Having occasional sexual partners was associated with syphilis and HSV2. Being over 36 years old and having more than 3 children were associated with HBV. The number of sexual partners, history of prostitution and rape, having sexual intercourses in prison and detention time were not associated with any of these infections. Discussion: The prevalence of syphilis, HIV, HSV2 and HBV was higher in this vulnerable female population than in the general population in Bolivia. Control measures in detention are needed to limit the spread of these infections both in prisons and in the community

Levantar las barreras al diagnóstico de la sífilis en las cárceles gracias a una prueba diagnóstica rápida / Rapid diagnostic testing to improve access to screening for syphilis in prison

Objetivos: Evaluar una prueba treponémica rápida in situ para el diagnóstico de la sífilis en mujeres privadas de libertad en Bolivia. Material y métodos: Se realizaron pruebas serológicas para la sífilis a 219 mujeres privadas de libertad (MPL) de la cárcel San Sebastián de Cochabamba, Bolivia. Esta enfermedad fue diagnosticada utilizando como referencia las pruebas serológicas reagina plasmática rápida (RPR, rapid plasma reagin, bioMérieux S.A.) y el ensayo de aglutinación de partículas de Treponema pallidum (TPPA, Treponema pallidum particle assay, Serodia(R) Fujirebio Inc.). Los resultados fueron comparados con la prueba rápida Alere DetermineTM Syphilis TP (PRADS) en sangre total. Se compararon también dos pruebas de anticuerpos treponémicos fluorescentes (FTA, fluorescent treponemal antibody) de marcas diferentes (bioMérieux y Biocientífica). Resultados: Las 28 mujeres privadas de libertad con RPR+/TPPA+ tenían la PRADS positiva (con una sensibilidad del 100%). Once participantes tenían la PRADS positiva sin RPR y TPPA, ambos reactivos; sin embargo, siete de ellos tenían la RPR o TPPA reactivo. De las 33 participantes con FTA-bioMérieux reactivo, 22 (el 66,6%) tenían el FTA-Biocientífica reactivo. Discusión: La PRADS muestra un excelente desempeño como prueba de despistaje en una población de mujeres privadas de libertad afectada por una alta prevalencia de sífilis. Esta herramienta está particularmente indicada cuando existen en las cárceles barreras de acceso a las pruebas serológicas convencionales. Es de bajo costo, de fácil uso y no necesita electricidad ni una infraestructura de laboratorio. La prueba treponémica FTA realizada con los reactivos Biocientífica tiene una sensibilidad subóptima

Objectives: To assess the accuracy of on-site rapid treponemal test for syphilis diagnosis in women deprived of liberty in Bolivia. Material and methods: Serological tests for syphilis were performed on 219 women deprived of liberty from the San Sebastián prison in Cochabamba, Bolivia. Syphilis was diagnosed using RPR (bioMérieux) and TPPA (Fujirebio) serological tests, and the results were compared to on-site rapid treponemal test (Alere DetermineTM Syphilis TP) in whole blood. Diagnostic performance of two FTA tests were also compared (bioMérieux and Biocientífica). Results: All participants (28) with RPR+/TPPA+ had the rapid syphilis test positive (sensitivity 100%). Eleven participants had rapid syphilis test positive without RPR and TPPA both positive; nevertheless 7 of them had RPR or TPPA positive. Of 33 participants with FTA-bioMérieux positive, 22 (66.6%) had FTA-Biocientífica positive. Discussion: The rapid syphilis test Determine shows excellent performance as a screening tool among women deprived of liberty affected by high prevalence of syphilis. This test is particularly indicated when there are barriers for access to conventional serological tests. It is inexpensive, easy to use and does not require electricity and laboratory infrastructure. The FTA test performed with reagents from Biocientífica had a suboptimal sensitivity

MV140, a sublingual polyvalent bacterial preparation to treat recurrent urinary tract infections, licenses human dendritic cells for generating Th1, Th17, and IL-10 responses via Syk and MyD88.

Recurrent urinary tract infections (RUTIs) are one of the most common bacterial infectious diseases, especially in women. Antibiotics remain the mainstay of treatment, but their overuse is associated with antibiotic-resistant infections and deleterious effects in the microbiota. Therefore, alternative approaches are fully demanded. Sublingual immunization with MV140 (Uromune), a polyvalent bacterial preparation (PBP) of whole heat-inactivated bacteria, demonstrated clinical efficacy for the treatment of RUTIs, but the involved immunological mechanisms remain unknown. Herein, we demonstrated that MV140 endorses human dendritic cells (DCs) with the capacity to generate Th1/Th17 and IL-10-producing T cells by mechanisms depending on spleen tyrosine kinase (Syk)- and myeloid differentiation primary response gene 88 (MyD88)-mediated pathways. MV140-induced activation of nuclear factor κB (NF-κB) and p38 in human DCs is essential for the generated Th1/Th17 and IL-10 immune responses whereas c-Jun N-terminal Kinase (JNK) and extracellular-signal regulated kinase (ERK) contribute to Th1 and IL-10 responses, respectively. Sublingual immunization of BALB/c mice with MV140 also induces potent systemic Th1/Th17 and IL-10 responses in vivo. We uncover immunological mechanisms underlying the way of action of MV140, which might well also contribute to understand the rational use of specific PBPs in other clinical conditions with potential high risk of recurrent infections.

Demencia rápidamente progresiva en un varón de 81 años / Rapidly progressive dementia in an 81 year-old man

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Anestesia para sustitución valvular en el segundo trimestre del embarazo / Anaestheia for valve replacement in the second trimester of pregnancy

La cirugía cardíaca en la mujer embarazada puede plantear diversos problemasanestésicos, ya que tanto la madre como, fundamentalmente, el feto tienen riesgo de elevadamorbimortalidad. En ese contexto, la circulación extracorpórea es el momento más complejodebido a los riesgos de hipoxia fetal que conlleva. La ausencia, por motivos éticos, de estudiosprospectivos que avalen pautas de manejo intraoperatorias universalmente aceptadas hacenque los clínicos que nos enfrentamos a estas pacientes nos apoyemos en bibliografía basada encasos clínicos. Asimismo, estos procedimientos requieren que el trabajo en equipo sea sobresa-liente. Presentamos el caso de una mujer embarazada de 19 semanas que requirió un recambiovalvular mitral, el cual se desarrolló con éxito y permitió culminar su gravidez sin complicacio-nes ni para la madre ni para su hijo. Detallamos también las referencias publicadas en las quebasamos nuestro proceder (AU)

Cardiac surgery in the pregnant woman gives rise to several anesthetic challenges,as the mother, but mainly the fetus, have a risk of high morbidity and mortality. In this context,the cardiopulmonary bypass is the most complex period, owing to the risks of fetal hypoxiait entails. Due to the absence, for ethical reasons, of prospective trials that provide genera-lly accepted guidelines in intraoperative management, it means that physicians have to workbased on case reports in the literature. These procedures also require team coordination tobe successful. The case is presented of a 19 weeks pregnant woman, who required a mitralvalve replacement, which was achieved with success, and enabled her to complete her preg-nancy without complications. Details are provided on the published references on which ourmanagement was based (AU)

[Anaestheia for valve replacement in the second trimester of pregnancy]. / Anestesia para sustitución valvular en el segundo trimestre del embarazo.

Cardiac surgery in the pregnant woman gives rise to several anesthetic challenges, as the mother, but mainly the fetus, have a risk of high morbidity and mortality. In this context, the cardiopulmonary bypass is the most complex period, owing to the risks of fetal hypoxia it entails. Due to the absence, for ethical reasons, of prospective trials that provide generally accepted guidelines in intraoperative management, it means that physicians have to work based on case reports in the literature. These procedures also require team coordination to be successful. The case is presented of a 19 weeks pregnant woman, who required a mitral valve replacement, which was achieved with success, and enabled her to complete her pregnancy without complications. Details are provided on the published references on which our management was based.

Mesoporous silicon microparticles enhance MHC class I cross-antigen presentation by human dendritic cells.

The mesoporous silicon microparticles (MSMPs) are excellent vehicles for releasing molecules inside the cell. The aim of this work was to use MSMPs to deliver viral specific MHC class I restricted epitopes into human antigen presenting cells (monocyte derived dendritic cells, MDDCs) to facilitate their capture, processing, and presentation to CD8+ (cytotoxic) T lymphocytes. We show for the first time that MSMPs vehiculation of antigenic peptides enhances their MHC class I presentation by human MDDCs to CD8 T lymphocytes.

Dissimilar expression of multidrug resistance mdr1 and bcrp by the replication of hepatitis C virus: role of the nonstructural 5A protein.

Multidrug resistance associated with the overexpression of ATP-dependent binding cassette (ABC) proteins is widely accepted as an important cause of treatment failure in patients with neoplastic or infectious diseases. Some of them play also a pivotal role in detoxification processes. Herein, we investigated the effect of hepatitis C virus (HCV) replication and nonstructural 5A (NS5A) protein on the expression and functional activity of two ABC transport proteins: MDR1 and BCRP. RT-quantitative real-time polymerase chain reaction (qPCR) was carried out for mdr1 and bcrp mRNAs in both Huh7 cells expressing NS5A and Huh7.5 cells containing either full-length- or subgenomic-HCV replicon systems. The functional activity of these pumps was studied by performing a dye efflux assay with DiOC2 and Rhodamine 123. A dose-dependent down-regulation of mdr1 expression was documented in Huh7 cells expressing the NS5A protein, as well as in both replicon systems. In contrast, a significant increase of bcrp expression in both systems was recorded, which were in full agreement with the dye efflux assay results. These results warrant further in vivo studies in HCV patients with cholestasis and/or patients that are refractive to the pharmacotherapy due to the activity of these pumps.

[In vivo antiplasmodial activity of Mycale laxissima and Clathria echinata sponges]. / Actividad antiplasmodial in vivo de las esponjas Mycale laxissima y Clathria echinata.

INTRODUCTION: the search of new antimalarial compounds comprises, among its challenges, the development of therapeutic alternatives for cerebral malaria; due to the high mortality and neurological deficiencies that persist after treatment with recommended drugs. OBJECTIVES: to evaluate the activity of organic fractions of Mycale laxissima and Clathria echinata in the cerebral malaria model of infection of C57BL/6 mice with Plasmodium berghei ANKA. METHODS: preparative fractions of both species were obtained by reverse-phase flash chromatography. In order to detect the presence of saponins, triterpenods/steroids and alkaloids, a qualitative chemical analysis was performed. The schyzontocidal effect of the extracts was determined by the suppression test at the beginning of the infection. Survival, neurological symptoms and body weight changes were evaluated in subsequent days. RESULTS: the organic fractions of Mycale laxissima at 200 mg/kg and Clathria echinata at 100 mg/kg showed neither substantial reductions of body weights, nor deaths of animals until day 4; but caused significant reductions of median parasitemia of 45 % and 53 % respectively. The fraction of Mycale laxissima at 200 mg/kg caused a significant increase in the median survival time up to day 20, whereas animals treated with Clathria echinata at 100 mg/kg presented a survival of 16 days. Both increases the survival time 7 days. Neurological alterations were not observed in the groups treated with organic fractions when compared to the control group. This survival extension was similar to the effect of administration of 7.5 mg/kg of chloroquine. CONCLUSIONS: the organic fractions of Mycale laxissima and Clathria echinata exhibited promising antimalarial activities in the infection model of C57BL/6 mice with Plasmodium berghei ANKA. This indicates that their active chemical constituents should be studied.

[Increase of analytical sensitivity of FasciDIG system for the diagnosis of Fasciola hepatica]. / Incremento de la sensibilidad analítica del sistema FasciDIG para el diagnóstico de Fasciola hepatica.

INTRODUCTION: fasciolosis is an endemic disease in cattle in Cuba and there is an increase in the number of reported human cases in recent years. The coproparasitological diagnosis of fasciolosis has low sensitivity and is hard-working; for that reason, it is important to use immunoenzymatic methods mainly those that can detect this parasite antigens in the feces. A system for antigen detection called FasciDIG, with a reported sensitivity of 10 ng/mL has been developed in "Pedro Kouri" Institute of Tropical Medicine. OBJECTIVE: to increase the sensitivity of FasciDIG through some modifications to this diagnostic method. METHODS: two foul dilutions (concentrations of antigen 1 000 ng/mL- 1.95ng/mL in H20 Tween-20) were evaluated in a simulated system using FasciDIG and modified FasciDIG. The FasciDiG was modified using the secondary antibody obtained from rabbit against excretory-secretory antigens of Fasciola hepatica combined with biotin and then adding commercial conjugated extravidine peroxidase. Feces were collected from the rectum of 96 animals for slaughter and were evaluated by both methods, FasciDig and modified FasciDig. Kappa index was calculated between both assays. RESULTS: the detection limit for the FasciDIG was 3.9 ng/mL whereas the modified FasciDIG detected up to 1.95 ng/mL. The agreement index calculated between the two tests was 0.6238 corresponding to an index of substantive or good agreement. CONCLUSIONS: the modified method is more sensitive than FasciDIG and it can supplement the diagnosis of fasciolosis. The number of analyzed samples should be increased and the sensitivity and specificity should also be determined using the serial conic-cup sedimentation technique as the gold standard.

Mioma vaginal: reporte de un caso / Vaginal myoma: case report

Presentar un caso de mioma vaginal en una mujer de 52 años. Paciente asintomática, que acude a la consulta para control ginecológico. Se detecta una lesión en cara posterior de vaginal, sobre elevada e hiperpigmentada de aproximadamente 1 cm de diámetro, la cual fue extirpada con asa diatérmica; se envió el material para estudio histopatológico y el resultado fue leiomioma en vagina con hiperpigmentación melánica en la capa basal del epitelio. La paciente evolucionó bien

Vaginal myomas are very rare, generally asymptomatics, but could be presented with diverse symptoms regarding their localization and do not differ from their uterine counterparts. We present a clinic case of a 52 years old woman, asymptomatic, in whom a 1 cm sobreelevated, hyperpigmentated lesion was found on the posterior vaginal wall, which was removed with diathermical loop excision. Her pathological result was vaginal leiomyoma with melanical hyperpigmentation of the basal layer of the epithelium. We also present a literature revision

The effect of dentine-bonding agents on substance P release in human dental pulp.

AIM: To quantify the effect of dentine-bonding agents on Substance P (SP) release in healthy human dental pulp tissue. METHODOLOGY: Forty pulp samples were obtained from healthy pre-molars where extraction was indicated for orthodontic reasons. In thirty of these pre-molars, a standardized Class V cavity preparation was performed, and teeth were divided equally into three groups: (i) Unetched-cavity control group: Class V cavities only; (ii) Experimental Group I: 'One-step' self-etch bonding agent was placed in the cavity; and (iii) Experimental Group II: 'Two-step' total-etch bonding agent was placed in the cavity. The remaining ten healthy pre-molars where extracted without treatment and served as an intact-teeth control group. SP was measured by radioimmunoassay. RESULTS: Greater SP release was found in the 'one-step' bonding agent group, followed by the 'two-step' bonding agent group and the unetched-cavity control group. The lower SP values were for the intact-teeth control group. anova showed statistically significant differences between groups (P = 0.0001). Tukey HSD post hoc tests showed statistically significant differences in SP release between the intact-teeth control group and the three other groups (P < 0.01) and between the unetched-cavity control group and the 'one-step' bonding agent group (P < 0.05). No significant difference was found between the 'two-step' bonding agent and the unetched-cavity control group. CONCLUSION: Dentine-bonding agents placed over Class V cavity preparations increased SP release. One-step dentine-bonding agents increased SP release most.

Expression of insulin-like growth factor-1 and proliferating cell nuclear antigen in human pulp cells of teeth with complete and incomplete root development.

AIM: To quantify the expression of insulin-like growth factor-1 (IGF-1) and proliferating cell nuclear antigen (PCNA) in human pulp cells of teeth with complete or incomplete root development, to support the specific role of IGF-1 in cell proliferation during tooth development and pulp reparative processes. METHODOLOGY: Twenty six pulp samples were obtained from freshly extracted human third molars, equally divided in two groups according to root development stage (complete or incomplete root development). All samples were processed and immunostained to determine the expression of IGF-1 and PCNA in pulp cells. Sections were observed with a light microscope at 80x and morphometric analyses were performed to calculate the area of PCNA and IGF-1 immunostaining using digital image software. Mann-Whitney's test was used to determine statistically significant differences between groups (P < 0.05) for each peptide and the co-expression of both. RESULTS: Expression of IGF-1 and PCNA was observed in all human pulp samples with a statistically significant higher expression in cells of pulps having complete root development (P = 0.0009). CONCLUSION: Insulin-like growth factor-1 and PCNA are expressed in human pulp cells, with a significant greater expression in pulp cells of teeth having complete root development.

Two simultaneous hepatitis B virus epidemics among injecting drug users and men who have sex with men in Buenos Aires, Argentina: characterization of the first D/A recombinant from the American continent.

Previous studies have revealed that hepatitis B virus (HBV)/D and HBV/F predominate among blood donors from Buenos Aires, Argentina. In the present study, blood samples from two high-risk groups were analysed: 160 corresponding to street- and hospital-recruited injecting drug users [81.2% showing the 'anti-hepatitis B core antigen (anti-HBc) only' serological pattern] and 20 to hepatitis B surface antigen (HBsAg)(+)/anti-HBc(+) men who have sex with men. HBV genotypes were assigned by polymerase chain reaction amplification followed by restriction fragment length polymorphism and confirmed by nucleotide sequencing of two different coding regions. HBV DNA was detected in 27 injecting drug users (16.9%, occult infection prevalence: 7.7%), and 14 men who have sex with men (70%). HBV/A prevailed among injecting drug users (81.8%) while HBV/F was predominant among men who have sex with men (57.1%). The high predominance of HBV/A among injecting drug users is in sharp contrast to its low prevalence among blood donors (P = 0.0006) and men who have sex with men (P = 0.0137). Interestingly, all HBV/A S gene sequences obtained from street-recruited injecting drug users encoded the rare serotype ayw1 and failed to cluster within any of the known A subgenotypes. Moreover, one of the HBV strains from a hospital-recruited injecting drug user was fully sequenced and found to be the first completely characterized D/A recombinant genome from the American continent. Data suggest that two simultaneous and independent HBV epidemics took place in Buenos Aires: one spreading among injecting drug users and another one sexually transmitted among the homosexual and heterosexual population.

Analysis of behavior-related excitatory inputs to a central pacemaker nucleus in a weakly electric fish.

Gymnotid electric fish explore their environment and communicate with conspecifics by means of rhythmic electric organ discharges. The neural command for each electric organ discharge arises from activity of a medullary pacemaker nucleus composed of two neuronal types: pacemaker and relay cells. During different behaviors as in courtship, exploration and agonistic interactions, these species display specific electric organ discharge frequency and/or waveform modulations. The neural bases of these modulations have been explained in terms of segregation of inputs to pacemaker or relay cells, as well as differential activation of the glutamate receptors of these cells. One of the most conspicuous electric organ discharge frequency modulations in Gymnotus carapo results from the activation of Mauthner cells, a pair of reticulospinal neurons that are involved in the organization of sensory-evoked escape responses in teleost fish. The activation of Mauthner cells in these animals produces a prolonged increase in electric organ discharge rate, whose neural mechanisms involves the activation of both N-methyl-D-aspartate (NMDA) and metabotropic glutamatergic receptors of pacemaker cells. Here we provide evidence which indicates that pacemaker cells are the only cellular target of the synaptic inputs responsible for the Mauthner cell initiated electric organ discharge modulation at the medullary pacemaker nucleus. Additionally, although pacemaker cells express both NMDA and non-NMDA ionotropic receptors, we found that non-NMDA receptors are not involved in this synaptic action which suggests that NMDA and non-NMDA receptor subtypes are not co-localized at the subsynaptic membrane. NMDA receptor activation of pacemaker cells seems to be an efficient neural strategy to produce long-lasting enhancements of the fish sampling capability during Mauthner cell-initiated motor behaviors.