Malathion Affects Spermatogenic Proliferation in Mouse / Malathion Afecta la Proliferación Espermatogénica del Ratón

The restriction of the mechanisms of cell proliferation in murine seminiferous epithelium, in terms of induction of programmed cell death until recently has not been fully analyzed. The aim of this work was to assess the effect of Malathion (MP) on testicular morphology and function in mouse spermatogenesis. For the experiments, male albino mice of strain NMRI-IVIC, weighing between 30-40 g were used, and divided into control and experimental groups of 5 each. The animals of the experimental groups were injected with a single dose of MP: 241mg/kg weight (1/12 LD 50 ) resuspended in 0.9% saline, intraperitoneally. Animals were sacrificed at 8.3, 16.6 and 33.2 days post-injection (first, second and third spermatogenic cycles). Testicular samples were obtained for light microscopy (LM), transmission electron microscopy procedures, and to detect apoptosis and p53 antigen by immunohistochemical methods. Blood was collected to quantify testosterone and plasmatic cholinesterase activity. From 8.3 days, Sertoli cell vacuolization, karyolisis of pachytene spermatocytes and Leydig cells and a decreased in average of the diameter of seminiferous tubules was observed. No damage to inter-Sertoli cells junctions was detected. Percentage of seminiferous tubules showing germ cells apoptosis was increased from 8.3 days, plasmatic acetylcholinesterase activity was reduced in the group treated only 24 hours after administration of MP. Serum testosterone levels were low in treated animals at 16. 6 and 33.2 days. p53 was mostly expressed in pachytene spermatocytes from 8d. The findings of this study indicate that MP alters the testicular function affecting the DNA and interfering with spermatogenesis as well as steroidogenesis.

La restricción de los mecanismos de proliferación celular en epitelio seminífero murino, en términos de inducción de muerte celular programada hasta hace poco no había sido completamente analizada.El objetivo de este trabajo fue evaluar el efecto de malathion (MP) sobre la morfología y la función testicular del ratón.Ratones macho albinos de la cepa NMRI-IVIC, con pesos entre 30-40 g fueron utilizados, se dividieron en grupos control y experimental. Los grupos experimentales fueron inyectados por vía intraperitoneal con una dosis única deMP:241mg/kg de peso (1/12 DL50) resuspendido en 0,9% de solución salina.Los animales fueron sacrificados en el día 8,3, 16,6 y 33,2 después de la inyección (primer, segundo y tercer ciclos de la espermatogénesis).Se obtuvieron muestras de testículo para estudio en microscopía de luz (ML), microscopía electrónica de transmisión, para la detección de apoptosis y el antígeno p53 (proliferación celular), por métodos inmunohistoquímicos.Se recogió sangre para cuantificar la testosterona y la actividad plasmática de colinesterasa.Desde el día 8,3 día se observó vacuolización de células de Sertoli, cariolisis de espermatocitos en paquiteno y células de Leydig, y una disminución en el promedio del diámetro de los túbulos seminíferos. No se detectó daño en las uniones entre células de Sertoli. El porcentaje de túbulos seminíferos que mostraban células germinales en apoptosis se incrementó a los 8,3 días, laactividad de la acetilcolinesterasa plasmática se redujo en el grupo tratado sólo 24 horas después de la administración de MP.Los niveles séricos de testosterona disminuyeron en los animales tratados a los 16,6 y 33,2 días.P53 se expresó sobre todo en los espermatocitos en paquiteno desde los 8,3 días.Los resultados de este estudio indican que MP altera la función testicular, afecta al ADN e interfiere con la espermatogénesis, así como con la esteroidogénesis.

Interferon gamma-signature transcript profiling and IL-23 upregulation in response to Helicobacter pylori infection.

Helicobacter pylori infection is the major cause of gastroduodenal pathologies including gastric cancer. The long persistence of bacteria and the type of immune and inflammatory response determine the clinical issue. In this study, the global gene expression profile after 6 and 12 months of H. pylori infection was investigated in the mouse stomach, using the Affymetrix GeneChip Mouse Expression Array A430. Genes related to the inflammatory and immune responses were focused. Levels of selected transcripts were confirmed by reverse transcription polymerase chain reaction. Twenty- five and nineteen percent of the differentially expressed genes observed at 6 and 12 months post-infection respectively, were related to immune response. They are characterized by an interferon (IFN)gamma-dependent expression associated to a T helper 1 (Th1) polarised response. In-depth analysis revealed that an up-regulation of IL-23p19, took place in the stomach of H. pylori infected-mice. Strong IL-23p19 levels were also confirmed in gastric biopsies from H. pylori-infected patients with chronic gastritis, as compared to healthy subjects. Our microarray analysis revealed also, a high decrease of H+K+-ATPase transcripts in the presence of the H. pylori infection. Association of gastric Th1 immune response with hypochlorhydria through the down-regulation of H+K+-ATPase contributes to the genesis of lesions upon the H. pylori infection. Our data highlight that the up-regulation of IL-23 and of many IFNgamma signature transcripts occur early on during the host response to H. pylori, and suggest that this type of immune response may promote the severity of the induced gastric lesions.

Human gastric epithelium produces IL-4 and IL-4delta2 isoform only upon Helicobacter pylori infection.

Recent evidence suggests that interleukin-4 (IL-4) is related to mucosal tolerance by which an injurious immune response is prevented, suppressed or shifted to a non-injurious response. We investigated the expression of IL-4 and its splice variant isoform IL-4delta2 in gastric epithelial cells of healthy subjects and gastritis patients infected with Helicobacter pylori (H. pylori) with or without the cag pathogenicity island (cag-PAI). IL-4 and IL-4delta2 mRNAs were evaluated in microdissected gastric epithelium and in AGS cell lines co-cultured with H. pylori B128 or SS1 strains. IL-4 mRNA was consistently detected in microdissected gastric epithelial cells from healthy subjects. The IL-4 mRNA expression was low in H. pylori?infected patients, and markedly reduced in cag-PAI-positive ones. IL-4delta2 mRNA was expressed on gastric epithelium of H. pylori-infected patients, but not in healthy subjects. The IL-4delta2 expression was lower in cag-PAI-positive than in cag-PAI-negative H. pylori infected patients. AGS cells also produced IL-4 mRNA upon SS1 strain stimulation, whereas IL-4delta2 mRNA expression was detected in AGS co-cultured with either SS1 or B128 strains. An inverse correlation was documented between IL-4 and IL-4delta2 mRNA expression by microdissected gastric epithelial cells and the score of gastritis. IL-4, but not IL-4delta2, is expressed by gastric epithelium of healthy subjects, whereas IL-4delta2 and lesser IL-4 mRNA are detectable in the gastric epithelium of H. pylori-infected patients. Data suggest that gastric epithelial cells might regulate the balance between tolerance and immune response by the fine tuning of IL-4 and IL-4delta2 expression.

Prevalencia de amebiasis extraintestinal en el estado Bolívar, Venezuela: durante el período 1996-2001 / Extraintestinal amebiasis prevalence in Bolívar state, Venezuela, from 1996-2001

La Amebiasis Extraintestinal es una presentación de la forma intestinal que implica complicaciones severas. El objetivo de este estudio fue determinar la prevalencia de la amebiasis extraintetinal en el estado Bolívar. Se realizó un estudio descriptivo-retrospectivo de los casos de amebiasis extraintestinal del estado durante el período 1996-2001. La única forma de amebiasis extraintestinal encontrada fue el absceso hepático amebiano (6 casos), con una prevalencia de 7,1/1.000 pacientes hospitalizados con amebiasis. El sexo que predominó fue el masculino (4:2). La edad osciló entre 36 y 73 años. Las manifestaciones clínicas presentadas fueron; fiebre, dolor abdominal, hiporexia y hepatomegalia. Se evidenció anemia (n=6), neutrofilia (n=4) y elevación de las aminotransferasas. El diagnóstico se realizó mediante e ecosografía, tomografía y demostración de anticuerpos específicos para E.histolytica. Para el tratamiento se utilizó metronidazol en todos los casos, asociándose con otro antibiótico en 4 pacientes. La amebiasis extraintestinal es poco frecuente en los principales hospitales del estado Bolívar y el absceso hepático amebiano constituye la única forma de presentación.

[In vitro antifungal susceptibility of dematiaceous filamentous fungi using the E-test]. / Sensibilidad in vitro de hongos dematiáceos a los antifúngicos utilizando E-test.

The usefulness of the E-test((R) )has been studied to determine the in vitro susceptibility of 52 isolates of 17 species to five antifungal drugs: amphotericin B, 5-flucytosine, ketoconazole, itraconazole and fluconazole. Minimal inhibitory concentrations were determined following the manufacturers' instructions, except in the preparation of the inoculum. In this case a spectrophotometric method was used to obtain 1-5 ' 10(6) CFU/ml. Two different culture media were included: casitone-agar and RPMI 1640 agar. Most isolates showed clear growth in both media after 96 h of incubation at 37 degrees C. The species showed low MIC concentrations to ketoconazole and itraconazole. Only 55.8% of isolates showed MICs

Sensibilidad in vitro de hongos dematiáceos a los antifúngicos utilizando E-test® / Antifungal susceptibility of dematiaceous filamentous fungi using the E-test®

Se ha determinado la concentración mínima inhibitoria (CMI) mediante E-test® en 52 aislamientos de hongos filamentosos dematiáceos pertenecientes a 17 especies. Se han utilizado los cinco antifúngicos sistémicos disponibles comercialmente: amfotericina B, 5-fluorocitosina, ketoconazol, fluconazol e itraconazol. Se ha utilizado el método recomendado por los fabricantes, con la excepción de la preparación del inóculo, que para que fuera más preciso se ha estandarizado por espectrofotometría hasta obtener 1 a 5x 106 UC/ml. Todas las cepas fueron sembradas simultáneamente en dos medios de cultivo: agar casitona y agar RPMI 1640. El crecimiento de casi todos los aislamientos fue evidente a partir de las 96 horas de incubación. El 55,8 por ciento de las cepas presentaron una CMI £2 mg/l para la amfotericina B y el 98 por ciento una CMI de 32 mg/l para la 5-fluorocitosina. Todas las especies mostraron valores bajos de CMI para el itraconazol y el ketoconazol, con una media geométrica de 0,19 y 0,26 mg/l, respectivamente. Excepto una cepa, con CMI de 8 mg/l, el resto presentaron valores ñ256 mg/l para el fluconazol. No se encontraron diferencias en los valores de las CMI para ambos medios de cultivo y la reproducibilidad fue del 100 por ciento; no obstante, la lectura de las CMI resultó más fácil con el agar casitona debido a un mejor contraste de la elipse de inhibición. Estos resultados ugieren que el itraconazol y el ketoconazol podrían ser los antifúngicos de primera elección en el tratamiento de las infecciones producidas por las especies evaluadas. Se considera que el E-test® es una prueba adecuada para determinar la sensibilidad in vitro a los antifúngicos en hongos filamentosos dematiáceos (AU)

[In vitro susceptibility of dematiaceous fungi to ten antifungal drugs using an agar diffusion test]. / Sensibilidad de hongos miceliares dematiaceos a diez antifúngicos empleando un método de difusión en agar.

We assessed the usefulness of an agar diffusion method, NeoSensitabs, to determine in vitro sensitivity of 52 isolates of dematiaceous filamentous fungi against ten antifungal agents: amphotericin B, 5-fluorocytosine, ketoconazole, fluconazole, itraconazole, terbinafine, bifonazole, miconazole, clotrimazole, and griseofulvin. For the preparation of the inoculum, a spectrophotometric method including both Shadomy and Casitone agar (CAS) culture media was used. Dematiaceous filamentous fungi were sensitive to itraconazole, terbinafine and bifonazole. Ketoconazole (90.4%), miconazole (71%), and clotrimazole (46%) showed a variable susceptibility pattern. Most species were resistant to griseofulvin and fluconazole (96%). All isolates were resistant to 5-fluorocytosine. Sixty-three percent of strains were susceptible to amphotericin B and 28.8% resistant. Inhibition zones in the antifungal susceptibility testing did not vary according to culture medium, although fungal growth was better in CAS. Variations in antifungal sensitivity in Exophiala spinifera and Fonsecaea pedrosoi spp. would justify an in vitro susceptibility study when indicating antifungal therapy. These results show that NeoSensitabs agar diffusion method is simple, rapid, and low-cost and can be available to many clinical laboratories for the study of in vitro sensitivity of dematiceous moulds.

Pathogenicity of Hansenula anomala in model of immunocompromised mice.

Systemic infections caused by opportunistic fungi have shown an increased frequency in the past 10 years, particularly in immunocompromised patients. Hansenula anomala is an ascosporogenous yeast of the Ascomycetes class found in the skin, throat, and digestive tract transient normal flora. This study was conducted to compare the pathogenicity of H. anomala and Candida albicans in a model of immunocompromised mice. Thirty-eight Swiss mice were divided into two groups as follows: 30 animals received an intraperitoneal (i.p.) injection of cyclophosphamide (200 mg/kg) four days before the induction of infection with H. anomala (1 x 10(6) yeasts/mL), and 8 animals received 100 mg/kg of cyclophosphamide at 3-day intervals during 3 weeks before inoculation of 1 x 10(7) yeasts/mL. All animals were treated with amoxicillin/clavulanic acid (40 mg/kg) four days before induction of infection. A group of mice inoculated with C. albicans (ATCC 64548) served as control. Tissue samples from the lung, spleen, liver, and kidney for histological and mycologic studies were obtained at necropsy. In each animal, the number of viable yeasts per gram of kidney was determined. The organs most frequently infected by H. anomala were the kidneys and the liver (20%), and the lung (10%). However, in conditions of sustained immunosuppression, H. anomala was found in 65.5% of the organs examined. It is concluded that in an experimental model of immunocompromised mice, the pathogenicity of H. anomala was low.

[Spectophotometric method for preparing the inocula of dematiaceous fungi.]. / Método espectrofotométrico en la preparación del inóculo de hongos dematiáceos.

The aim of this study was to adapt a spectrophotometric method for preparing the inocula of dematiaceous fungi used for in vitro susceptibility tests. Fifty-two isolates of 17 different species of dematiaceous fungi were used for this purpose. Homogeneous suspensions of conidia and hyphae of these isolates were obtained and adjusted for reading at 530 and 550 nm at 40% and 50% of transmittance. The suspensions were standardised to 1-5 x 10 e6 CFU/ml. Quality controls of the inocula were done by quantitative cultures on agar-Sabouraud plates. The inocula obtained by spectrophotometry showed little variability within all the isolates. This method can be useful for in vitro antifungal evaluation of dematiaceous fungi.

Predominance of gram-positive microorganisms as a cause of septicemia in patients with hematological malignancies.

OBJECTIVE: To ascertain the etiology and outcome of episodes of bacteremia and fungemia over a three-year period (1990-1992) in patients with hematological malignancies. DESIGN: Retrospective study. SETTING: Hematology service of a 1,500-bed Spanish university hospital. RESULTS: Of a total of 178 episodes of significant bacteremia or fungemia in 101 patients, 53% affected patients with acute leukemia. Gram-positive microorganisms were found to be the cause in 70% of the monomicrobial episodes. The most frequently isolated microorganism was coagulase-negative Staphylococcus (35%), followed by Staphylococcus aureus (11%). Most blood-stream infections occurred during an episode of neutropenia (59%). A total of 34 patients died during hospitalization; in 14, infection was the cause of death. CONCLUSIONS: A marked increase in the incidence of bacteremias caused by gram-positive microorganisms has been observed in our hospital over the last 10 years, especially in patients with hematological malignancies. The mortality due to bacteremia is similar to that found by other authors in series of bacteremia in hematological patients, and we have not found significant differences in the mortality due to bacteremia between neutropenic and non-neutropenic patients (Infect Control Hosp Epidemiol 1994;15:101-104).

[Trends in health services research in Mexico, 1984-1991]. / Tendencias de investigación en servicios de salud en México, 1984-1991.

Health services research is a basic tool for the development of the National Health System. This paper presents the results of a national survey on research projects carried out in Mexican health institutions, as well as in universities and research centers, from 1984 to 1991.

In vivo and in vitro cell-mediated responses in coccidioidomycosis. I. Immumologic responses of persons with primary, asymptomatic infections.

Chest roentgenograms of 58 children who were skin test positive to coccidioidin and resided in an area endemic for coccidioidomycosis revealed that 34 per cent had roentgenographic evidence of an inflammatory process, 14 per cent showed calcific densities, and 52 per cent showed no evidence of infection. The in vitro lymphocyte responses of children who had evidence of an inflammatory process (Group I) were compared with those of children who had calcific densities (Group II); those of children who were coccidioidin skin test negative and had normal chest roentgenograms (Group III); and those of patients who had active coccidioidomycosis (Group IV). The mean lymphocyte transformation responses (expressed as cpm times 10-(4)) of Groups I, II, III, and IV to a coccidioides antigen were 16.8, 19.5, 4.2, and 7.0, respectively. The mean migration inhibitory factor responses of these groups were 22.4, 20.0, 1.2, and 4.0 per cent, respectively. Thus, the over-all responses of children in Groups I and II were comparable to each other, whereas the responses of patients in Group IV were depressed to the extent that they were indistinguishable from those of coccidioidin skin test-negative donors in Group III. Follow-up chest roentgenograms taken 3 months after the immunologic assays were performed revealed that the one subject in Group I who had been nonresponsive in the lymphocyte assays had now stabilized his infection, as evidenced by calcifications. In contrast, the 2 subjects in Group I who had yet to stabilize their infection had exhibited strong in vitro lymphocyte responses. These findings suggest that primary, asymptomatic coccidioidomycosis is not associated with an immunologically nonresponsive state. However, patients with active, progressive coccidioidomycosis do have a depressed immunologic response to coccidioides antigens.