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We describe the life cycle of the bucephalid Prosorhynchoides carvajali from the intertidal rocky zone of central Chile. To elucidate the life cycle of this digenean, two mytilid bivalves, Semimytilus algosus and Perumytilus purpuratus, and ten intertidal fish species belonging to the families Blenniidae, Tripterygiidae, Labrisomidae, Kyphosidae and Gobiesocidae were analysed for natural infections. In addition, experimental infections of fish were undertaken and molecular analyses were performed of several developmental stages of the digeneans in various host species. Experimental infections of fish were made from infected mytilids to determine which fish species were suitable for the metacercarial stage of Prosorhynchoides. We also determined the abundance and prevalence of metacercariae in natural infections in fish and found that they were lower than in the experimental infections. A molecular analysis showed that sporocysts from S. algosus were identical to metacercariae from five fish species and P. carvajali adults. Sporocysts isolated from P. purpuratus were similar to metacercaria found in one fish species only (G. laevifrons) but were different from P. carvajali, with 1.9-2.0% genetic divergence. Therefore, the complete life cycle of P. carvajali consists of the mytilid species S. algosus as the first intermediate host, at least five intertidal fish species as second intermediate hosts (Scartichthys viridis, Auchenionchus microcirrhis, Hypsoblennius sordidus, Helcogrammoides chilensis and Gobiesox marmoratus), two carnivorous fish as definitive hosts (Auchenionchus microcirrhis and A. variolosus) and one occasional definitive host (Syciases sanguineus). This is the second description of a life cycle of a marine digenean from Chile.

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The aims of the present study were to compare, using multivariate analyses, the degree of similarity of the endoparasite fauna of five fish species belonging to the order Gadiformes: Merluccius gayi, Merluccius australis, Macruronus magellanicus (Gadoidei) and Micromesistius australis and Nezumia pulchella (Macrouroidei), from the southern and central Chilean coast, and to evaluate whether the composition of the endoparasite fauna was determined by phylogenetic or ecological relationships. We employed our database of Merluccius australis, M. magellanicus and Micromesistius australis, which was complemented with published information for M. magellanicus, Merluccius australis, Micromesistius australis, M. gayi and N. pulchella. A higher number of endoparasite species was recorded for Merluccius australis, Micromesistius australis and M. magellanicus, namely Anisakis sp. and Hepatoxylon trichiuri, which is the most prevalent parasite among these hosts. Aporocotyle wilhelmi and Hysterothylacium sp. were detected only in M. gayi, whereas Lepidapedon sp. was found exclusively in N. pulchella. These results suggest that fish ecology rather than host phylogeny was the most important factor for the determination of similarity in parasite composition. This result could be explained by the similar trophic patterns of hosts and by the predominance of generalist larval species among these fish parasite communities.

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Two species of Proctoeces Odhner, 1911 have been described in marine organisms from Chile: P. humboldti George-Nascimento & Quiroga (1983), parasitizing the gonads of keyhole limpets (Fissurella spp.), and P. chilensis Oliva (1984), an intestinal parasite of Sicyases sanguineus (Teleostei); both species were subsequently considered as P. lintoni Siddiqi & Cable (1960). To assist in the resolution of the taxonomic identification of Proctoeces species in marine organisms from Chile, phylogenetic studies using DNA sequences from the V4 region of the SSU rRNA gene were performed. Several specimens of P. lintoni were isolated from keyhole limpets (Fissurella spp.) and clingfish (S. sanguineus) from Bahia San Jorge (23°40'S) and Bahia Concepción (36°50'S). Phylogenetic analyses were conducted using three different approaches: a neighbour-joining (NJ), a maximum likelihood (ML) and Bayesian inference (BI). The phylogenetic analysis confirms that specimens of Proctoeces obtained from keyhole limpets and those specimens from the clingfish are in fact the same species. We prefer to consider our specimens as Proctoeces cf. lintoni, as the morphology of Proctoeces appears to be of doubtful value and genetic information about P. lintoni Siddiqi & Cable (1960) is not available. In addition, our results strongly suggest that there are at least three species in this genus.

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Three different hybridoma clones secreting anti-HBsAg antibody were constructed by fusing cells of mouse myeloma line Ag8-X63 with splenocytes from BALB/c mice immunized with recombinant HBsAg and natural HBV. The monoclonal antibodies obtained were characterized immunologically, and two were used to develop UMELISA for detection of HBsAg. This monoclonal assay enabled the detection of 0.1 UPE/mL with reference to the standard of the Paul Ehrlich Institute (Frankfurt, Germany). The assay compared well with a commercially available kit (UMELISA HBsAg) and was used for detection of HBsAg in blood donors.

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The follow-up of HBV markers in selected high infection risk populations, in patients from the hemodialysis and peritoneal dialysis services was used to assess the effectiveness of a special vaccination program. Viral infection markers were studied in prevalence cross sections of the whole population of patients, and also by recording the reports of clinical cases of hepatitis B occurred during that period in those groups of patients. The prevention program consisted of the vaccination of all patients negative to the viral markers and the indication of vaccination for the new cases during the period of the kidney disease, just before the start of the treatment at the hemodialysis unit; besides all the persons susceptible to infection that had already been included in the program, regardless of the stage of the disease. The results show the benefit of the vaccination in these patients, but it is more effective in the period before the treatment with dialysis where there is a lower possibility of being exposed to the virus and the immune system is still competent. Once the program was established, after a follow up o 6 years, there have been no reports of new cases of hepatitis B and the incidence of the disease has been declining.

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OBJECTIVE: To compare the effects of tibolone, estriol and conventional hormone replacement therapy (HRT) on mammographic parenchymal density in postmenopausal women. DESIGN AND SETTING: This was a non-randomised, prospective, longitudinal, comparative study conducted at two specialist outpatient clinics in Chile. PATIENTS AND PARTICIPANTS: 210 non-obese, postmenopausal women aged <65 years with a normal mammogram at baseline. METHODS: Participants received one of seven oral HRT regimens for 1 year. Treatments (daily doses) were: (i) estradiol 2mg; (ii) estradiol 2mg plus sequential medroxyprogesterone acetate (MPA) 5mg for 10 to 16 days/cycle; (iii) estradiol 2mg plus continuous MPA 2.5mg; (iv) combined equine estrogens (CEE) 0.625mg; (v) CEE 0.625mg plus sequential MPA 5mg; (vi) estriol 2mg; or (vii) tibolone 2.5mg. In addition, an age-matched group of 30 untreated control individuals was studied. RESULTS: Increased mammographic density occurred in 67, 57, 30, 43 and 27% of patients receiving regimens (i) to (v), respectively. No patients receiving tibolone or estriol experienced increases (both p < 0.05 vs conventional HRT). Overall, 67 of 210 treated patients [31.9%; 95% confidence interval (CI) 25.7%, 38.6%] experienced increases, compared with one of 30 controls (3.3%; 95% CI 0%, 17.2%). CONCLUSIONS: Neither the tissue-specific agent tibolone nor the short-acting estrogen estriol induced any breast density increase. Increased breast density was more frequent with regimens containing estradiol than CEE, and with unopposed rather than opposed regimens. Tibolone (or estriol, if suitable) may be a preferable HRT for women in whom this is a concern.

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The study evaluated the clinical efficacy substitutive hormonotherapy regime in a group of 40 postmenopausal, women with moderate to severe symptomatology and negative progesterone challenge test. Each cycle consisted in the administration of 15 micrograms of ethinyl estradiol during 21 days, plus 10 mg medroxyprogesterone acetate (MPA) the last 10 days. Each patient received four cycles of therapy with 10 days of interval between them. The global clinical response was evaluated as favorable (excellent and good responses) in 97.5% of the patients. All the patients showed an improvement of the vaginal trophism (colpocytology). The great majority of the women experimented cyclical bleeding as consequence of the treatment. The post-therapeutic bleeding (Withdrawal) was the predominant bleeding pattern. This fact suggests that the 10 mg of MPA added daily during 10 days could allow a suitable opposition to the estrogenic proliferative effect inducing an adequate secretory response and the subsequent endometrial desquamation.

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Se analizan 2.000 mamografias realizadas en nuestro centro, durante un periodo de dos anos. Las pacientes fueron referidas por diversos medicos, en su mayoria por sospecha de patologia mamaria y las restantes como control o pesquisa. Ademas del estudio mamografico, a todas las pacientes se les realizo una anamnesis dirigida consignando factores de riesgo y un examen fisico acucioso de sus mamas.Se analiza el valor de los distintos signos radiologicos que fundamentaron el diagnostico de cancer mamario, (imagem espiculada, microcalcificaciones patologicas), su correlacion con los antecedentes clinicos y los informes histologicos. Se calcula el valor predictivo y sensibilidad para estos signos.Frente a la presencia de signos radiologicos directos, la histologia confirmo el diagnostico de malignidad en el 95,4%; y basado en signos indirectos, la histologia informo cancer en el 25,8%.En 25 pacientes se pesquiso un cancer minimo, y de estos 17 ocurrieron en mujeres entre 35 y 55 anos correspondiente al 68% del total de canceres minimos. El cancer minimo correspondio al 15,4% del total de canceres diagnosticados en nuestra serie, cifra que concuerda con resultados de experiencias estranjeras

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