Evolución alejada en portadores asintomáticos HBsAg (PA-HBsAg) en un area de baja prevalencia de hepatocarcinoma. / [Long-term course in asymptomatic carriers of HBsAg in an area of low prevalence of hepatocarcinoma]

Data provided by 51 voluntary blood donors identified as asymptomatic HBsAg carriers five to ten years (mean = 7.5 years) before their inclusion in the study are analysed towards their long-term evolution. HBsAg clearance was estimated 2.5

yearly and 83.9

of those remaining positive showed the classical non-replicative serological pattern; another 12.9

were negative for both HBeAg-Anti HBe (seroconversion window?), one of them presenting raised ASAT-ALAT levels and enhanced histological activity (lobular chronic hepatitis). Neither alpha-fetoprotein seric levels (RIA) nor liver ultrasonography demonstrated hepatocellular carcinoma suspicion signs in 35 HBsAg positive cases to this methods; ASAT-ALAT levels raised over two fold the normal superior limit in only 11.4

, and neither aggressive chronic liver disease nor hepatocyte dysplasia was showed in 17 biopsied cases (70.6

normal; 23.6

chronic reactive or chronic persistent hepatitis; 5.8

chronic lobular hepatitis). One out of five patients biopsied with a seven years interval showed histologic worsening.

Evolución alejada en portadoras asintomáticos HBsAg(PA-HBsAg) en un área de baja prevalencia de hepatocarcinoma

Data provided by 51 voluntaru blood donnors identified as asymptomatic HBsAg carriers five to ten years (x = 7.5 years) before their inclusion in the study are analysed towards their long-term evolution. HBsAg clearance was estimated 2.5% yearly and 83.9% of those remaining positive showed the classical non-replicative serological pattern,; another 12.9% were negative for both HBeAg - Anti HBe (serovonversion window?), one of them presenting raised ASATALAT levels and enhanced histological activity (lobular chronic hepatitis). Neither alpha-fetoprotein seric levels (RIA) nor liver ultrasonography demonstrated hepato cellular carcinoma suspicion signs in 35 HBsAg positive cases to this methods; ASAT-ALAT levels raised over two fold the normal superior limit ion only 11.4%, and neither agressive chronic liver disease nor hepatocyte dissplasia was showed in 17 biopsed cases (70.6% normal; 23.6% chronic reactive or chronic persistent hepatitis; 5.8% chronic liobular hepatitis). One out of five patients biopsed with a seven years interval showed histologic worsening (AU)

Factores que influyen en el desenquistamiento in vitro de Cryptosporidium sp / Factors affecting the in vitro excystation of Cryptosporidium sp

Para evaluar la viabilidad de los ooquistes de Cryptosporidium sp se desarrolló y optimizó una técnica de desenquistamiento in vitro. Los ooquistes de Cryptosporidium sp se obtuvieron de una muestra de materia fecal de un niño con cryptosporidiosis sintomática. La muestra fue procesada por la técnica de gradiente discontinuo de sacarosa hasta obtener una suspensión de ooquistes purificados y concentrados (OPC). Los ooquistes se cuantificaron en cámara de Neubauer y preservaron en PBS pH 7, 2 a 4ºC. Los dos protocolos ensayados a partir de alícuotas de 100Al de OPC con 178.000 ooquistes/mm3 fueron: I. Tratamiento con bilis 1 por ciento y bicarbonato de sodio al 0,44 por ciento a 37ºC durante 24 horas. II Tratamiento con bilis 1 por ciento con pH 6

Relación entre el gradiente discontinuo de sacarosa y la viabilidad de ooquistes de Cryptosporidium sp / Relationship between discontinuous sucrose gradient and viability of Cryptosporidium sp. oocysts

Cryptosporidium sp. causes self-limiting gastroenteritis in immunocompetent individuals and can produce a life-threatening chronic diarrhea in immunodeficient patients. In order to obtain populations of selectively infective oocysts for inoculation in biological experiments, we developed an operational protocol for the enrichment of viable oocysts from crude fecal material. Using either fresh or formaldehyde-fixed feces as sources of viable and nonviable oocysts, respectively, we fractionated the samples on parallel discontinuous sucrose gradients and evaluated oocyst viability at different banding densities by an in vitro excystation assay. The formaldehyde-inactivated fecal samples formed no bands after centrifugation and 91.66 of the oocysts became concentrated in the pellet. Fresh fecal samples formed three bands at densities 1.062, 1.092, and 1.121, in addition to a sediment. Here the viability of the gradient-sedimented oocysts was 92.3 overall, and of those in the second band 100. Modifications in oocyst permeability thus seems to alter their sedimentation characteristics so that consequent distribution on sucrose gradients can be correlated with oocyst viability. Discontinuous sucrose density gradient sedimentation would thus constitute a simple and rapid mean to obtain viable oocysts for use in biological models both in vivo and in vitro.(AU)

Asma y toxocarosis encubierta. / [Asthma and covert toxocariasis]

The relationship between asthma and covert toxocariasis was studied in 38 patients with asthma and 44 control individuals (without asthma). Inclusion/exclusion criteria were determined. An ELISA test based on the detection of Anti-Toxocara canis (E/S antigen) serum immunoglobulin G (Ig G) and E (Ig E) was determined in both groups. Ordinary allergens and E/S antigen of T. canis injections were used to evaluate cutaneous reactivity. The seroprevalence in patients with asthma was 68.42

, and in the control individuals was 13.63

. This difference was significant. The percentage of asthmatic patients with two antitoxocara antibodies was 26.31

and 4.54

in control individuals. All asthmatic patients with antitoxocara IgE had cutaneous reactivity to Ag E/S. We conclude that the asthmatic patients with IgE and IgG antitoxocara suffer a covert toxocarosis.

Técnicas de purificación y ruptura de quistes de Giardia spp. / [Purification and breaking techniques for cysts of Giardia spp]

The purpose of this study was to optimize and evaluate the purification techniques, isolation and breaking of cysts of Giardia spp from fecal samples to isolate DNA. Filtrated fecal samples were tested in 3 purification techniques: Telleman solution, sucrose and Telleman plus sucrose. The sucrose solution let us to isolate the cysts with less detritus. The cleaned cysts were splited in 3 techniques to test the breaking: osmotic shock and heat, chemistry degradation and thermic shock, enzymatic action and mechanic effect. Only the last method was successful and showed bands in agarose gel. The result of this study shows a routine and common method which could be used in the previous steps to the PCR technique for the genotypification of these parasites.

Hepatitis no A-no B: significación epidemiológica en hepatitis viral aguda y hepatitis crónica activa de consulta hepatológica. / [Hepatitis non-A, non-B: epidemiological significance in acute viral hepatitis and chronic active hepatitis of hepatological consultation]

157 acute viral hepatitis and 60 chronic active ones have been analyzed focusing on NANB etiology. HAV was implicated in 36.3

of the hole acute viral hepatitis sample, HBV in 29.3

, and HNANBV was presumed as etiology in 31.2

, 5 patients (3.2

) had acute infection by HAV, on previous one by HBV, except for Epstein-Barr virus, no other test for viruses were determined (CMV, HSV, etc.). Male/female ratio was 1.4:1, 1.9:1, and 1.4:1 for HAV, HBV and HNANBV acute hepatitis respectively; HAV was the main etiology in the 0-9 age group (72.2

) although it only represents 11.5

of the sample; small occurrence of HAV hepatitis were found in patients over 40 (8.8

); HBV was clearly prevalent in patients over 50 (65.2

); the highest concentration of NANB etiology was found between 20-39 years old, but it was represented in all age-groups. Out of 49 NANB acute hepatitis, 12.2

had related transfusional antecedents, 12.2

belonged to health care worker group, and 4.1

had a close family NANB hepatitis contact; 71.5

had no reported antecedent. Viral source was presumably implicated in 75.0

of chronic active hepatitis, 25.0

attributable to HNANBV. Results seem not feasible to transfer to general population due to the facts that most patients were of specialized consult, and pediatric assistance is unusual to the authors practice.

Prevalencia de infección por virus B en odontólogos del Distrito I de la provincia de Bs. As. / [Prevalence of hepatitis B virus infection in dentists of District I of the province of Buenos Aires]

Two samples were analyzed; first survey carried out by 250 odontologists chosen out of total number of 1,500 dentists belonging to District I Province of Buenos Aires; the other, by 31 students out of the 180 who attended the last course at the School of Odontology in the National University of La Plata. Through the determination of anti-HBc by enzyme-immuno test, a prevalence of infection due to HBV of 9.6

was found in the odontologists sample. The prevalence is meaningfully higher than of the general population (5.8), therefore it is demonstrated for the first time in our medium that these professionals constitute a high-risk population. The prevalence found by the students (6.4) was not meaningfully different from that of the general population. The prevalence of an i-HBc found in each of the services taken into account was directly proportional to the number of patients daily assisted. The prevention and sterilization measures for HBV were proved to be unsuitable. No association between a certain HLA pattern and the different serological images, was found.

Antigenos HLA donantes de sangre portadores cronicos asintomaticos del antigeno de superfice (HBsAg) de la hepatitis viral tipo B. / HLA antigens in blood donors asymptomatic chronic carriers of hepatitis type B surface antigen (HBsAg)

La relacion entre los antigenos de histocompatibilidad del sistema HLA y la incidencia de positividad para el antigeno de superficie del virus de la hepatitis tipo B (HBsAg) ha sido estudiada por diversos investigadores en 3 grupos principales de individuos: a) pacientes con hepatitis cronica activa; b) pacientes con insuficiencia renal cronica, y c) portadores cronicos asintomaticos del HBsAg. Nuestro estudio se efectuo en 37 portadores cronicos asintomaticos del HBsAg, todos ellos donantes de sangre, en su mayoria hombres, en los cuales la presencia de HBsAg fue confirmado por radioinmunoensayo durante un ano como minino.Se utilizaron como grupo control normal, 257 personas de ambos sexos, blancos, sin relacion de parentesco. Se calculo el riesgo relativo que posee un individuo de ser portador de HBsAg segun la presencia de un determinado antigeno de histocompatibilidad. Se estudiaron 13 antigenos del locus A, 15 del locus B y 4 del locus C. Se encontro un aumento estadisticamente significativo en la frecuencia de los antigenos del locus B, el B 15 y el Bw21. Si se multiplica el valor p obtenido por el numero de antigenos estudiados (32), para obtener el valor corregido, solo la presencia aumentada del alelo Bw21 conserva su significado estadistico (p corrigido = 0,03). Aumentos en las frecuencias de los antigenos B15 y Bw21 han sido senalados tambien por otros autores

Prevalencia de infección por virus B en odontologos del Distrito I de la Provincia de Buenos Aires

Se analizaron dos muestras, la primera de 250 odontólogos extaidos de un universo compuesto por 1500 dentistas del Distrito 1 de la Provincia de Buenos Aires y otra de 31 estudiantes, tomados de los 180 que cursaron el último año de la carrera de Odontología dela U.N.L.P. En la muestra de odontólogos se halló, mediante la determinación de anti HBc por enzimo-inmuno-ensayo (E.L.I.S.A.), una prevalencia de infeccion por HBV de 9.6%. Esta prevalencia es significativamente superior a la de la población general (5.8%), con lo cual se demuestra por primera vez en nuestro medio, que estos profesionales constituyen también población de alto riesgo. La prevalencia hallada en los estudiantes (6.4%) no fue significativamente diferente a la de la población general. La prevalencia de anti HBc hallada en cada uno de los servicios considerados, se correlacionó en forma directamente proporcional con el número de pacientes asistidos diariamente. Se constató que las medidas de prevención y esterilización para el HBV eran inadecuadas. No se comprobó ninguna asociación entre determinado patrón de HLA y los distintos perfiles serológicos (AU)

Hepatitis no A - no B: significación epidemiológica en hepatitis viral aguda y hepatitis crónica activa de consulta hepatológica / Hepatitis non-A, non-B: epidemiological significance in acute viral hepatitis and chronic active hepatitis of hepatological consultation

1- La hepatitis aguda NANB representa en nuestro medio 31.2% de las hepatitis virales agudas; si bien estos porcentajes no son directamente transpolables a la población general, el especialista gastroenterólogo o hepatólogo, debe esperar que casi 1 de cada 3 pacientes de su consulta presente una hepatopatía con multitud de aspectos aun desconocidos, etiológicos, evolutivos, vinculación con el cáncer hepático, etc. 2- El predominio de la hepatitis aguda a HAV es neto en la infancia (0-9 años: 72.2%) y excepcional después de los 40 años, mientras que el HBV es etiología predominante por encima de los 50; los NANBV se presentan en todas las edades, con 77,6% de los casos entre 20-49. 3- Al no incluirse casos sub-clínicos post-transfusionales, generalmente provenientes de estudios de seguimiento, el porcentaje de forma agudas NANB presuntamente esporádicas es elevado (71.5%), aunque no debiera descartarse la posibilidad de acción en nuestro medio de formas de transmisión no-parenteral. 4- 25% de nuestra serie de hapatitis crónicas activas, es atribuido por exclusión a la etiología NANB, englobando posiblemente a otras causas aun no conocidas. 5- Estos aspectos epidemiológicos, así como otros clínico-evolutivos, variarán seguramente en los próximos años gracias a los esfuerzos realizados por investigadores de todo el mundo en la identificación etiológica y la puesta a punto de marcadores serológicos específicos de los hoy denominados virus de la hepatiti No A- No B (AU)

Aislamiento y caracterización de coliformes injuriados provenientes de la red de distribución de agua de bebida de La Plata, Argentina / Isolation and characterization of injured coliforms from the drinking water distribution network of La Plata, Argentina

We screened the La Plata drinking water distribution network for fecal and total coliform bacterial indicator by purification procedures, cultivating 66 membrane-filtered samples from the two networks on m-T7 agar. Subterranean and river-derived water yielded 13 and 18 confirmed gram-negative bacillus isolates, with 54 and 72 representing total coliforms, respectively. Those from the former source were Klebsiella oxytoca, Enterobacter agglomerans, and Enterobacter aerogenes and from the latter Klebsiella oxytoca, Enterobacter agglomerans, and Enterobacter cloacae, genomic group 3. Since 58 of the samples were positive using m-T7 medium it is suggested that the inclusion in standard quality control protocols should be implemented.(AU)

Aislamiento y caracterización de coliformes injuriados provenientes de la red de distribución de agua de bebida de La Plata, Argentina. / [Isolation and characterization of injured coliforms from the drinking water distribution network of La Plata, Argentina]

We screened the La Plata drinking water distribution network for fecal and total coliform bacterial indicator by purification procedures, cultivating 66 membrane-filtered samples from the two networks on m-T7 agar. Subterranean and river-derived water yielded 13 and 18 confirmed gram-negative bacillus isolates, with 54

and 72

representing total coliforms, respectively. Those from the former source were Klebsiella oxytoca, Enterobacter agglomerans, and Enterobacter aerogenes and from the latter Klebsiella oxytoca, Enterobacter agglomerans, and Enterobacter cloacae, genomic group 3. Since 58

of the samples were positive using m-T7 medium it is suggested that the inclusion in standard quality control protocols should be implemented.

Conjuntivitis folicular debida a Chlamydia trachomatis. / [Follicular conjunctivitis due to Chlamydia trachomatis]

During two years (1997-1999) an investigation of possible infections of chlamydial etiology in outpatients with follicular conjunctivitis was carried out, through the use of specific assays. Fifty-seven selected patients with presumptive inclusion conjunctivitis were diagnosed by means of ophthalmoscopic examination and bilateral tarsal-conjunctiva swabbing for microorganisms. The possible presence of Chlamydia trachomatis was tested by immunofluorescence microscopy and isolation in cell culture of McCoy line. Of the 57 conjunctivitis patients screened, 37 (65

) proved to be positive by cell culture (CC) and 27 (47

) by direct immunofluorescence (IFD). A good agreement between the two assays was observed, where the CC was more sensitive than IFD. Of these 37 patients with chlamydial conjunctivitis, 23 (62

) were women, with over one-third of them ranging in age from 45 to 65 years. Their clinical records revealed an evolution period of 1 to 12 months. Eighteen (78

) of these women reported previous genital pathology, while 4 (29

) of the 14 men had a history of urethritis by Chlamydia trachomatis. A high frequency of follicular conjunctivitis by Chlamydia (65

) in the screened patients was observed, without any evidence of urogenital signs and symptoms at the moment of the study.

Significación epidemiológica, valoración clínico-morfológica y comportamiento de factores patogenéticos, en portadores crónicos asintomáticos del HBsAg en el área de La Plata. Estudio en donantes voluntarios de sangre. / [Epidemiological significance, clinico-morphological evaluation and behavior of pathogenetic factors, in asymptomatic chronic carriers of the HBsAg in the La Plata area. Study in voluntary blood donors]

Seric positivity for HBsAg (CIED) investigated on 100.000 volunteer blood donors of La Plata city was 0.239

. Humoral findings on 40 cases only revealed TGO-TGP seric levels over twice the normal in 15 and 10

respectively. On 27 biopsied patients, chronic active hepatitis in one case and chronic persistent hepatitis in another one were found. Non-specific chronic inflammatory changes were seen in 18.5

. Correlation between TGO-TGP levels and histologic damage was generally proved. HBeAg seric positivity in 3/29 cases (10.3

) was accompanied of both raised TGO-TGP levels and some kind of chronic inflammatory change. Statistic high risk was determined for both O-Rh negative blood group and HLA-Bw21 individuals. Diminished cutaneous PPD reactivity without significative alteration of linfocite population was established.