The Negro River (Ancash-Peru): A unique case of water pollution, three environmental scenarios and an unresolved issue.

This paper is focused on the hydrogeochemical characterization of the Negro River along its course, as well as in the proposal of a functioning model for the contamination processes in order to establish potential cause-effect relationships between water quality, geology (ARD), mining activities (AMD) and the tectonic framework as transmission vector of acidity, metals and sulphates. The scenario shows a heavily-contaminated river compared to the unaffected regional background. By graphical and statistical treatments of physico-chemical data of Negro River and the unaffected values of regional background and other AMD/ARD representative rivers' it is possible to conclude that Antamina Mine, is not the cause of the Negro River contamination, without the need of isotopic tracers, but just through the inexistent concentrations of Cu, Bi and Mo found in the waters. In the proposed contamination model, climatic factors (glacial retreat) activate geological (ARD) processes. The tectonic scenario (faults) intervenes as a transport medium of the contamination flux from the sulphide oxidation surface in upper altitudes until the spring in lower altitudes. At the end, it is concluded that this contamination comes from the recent glacial retreat in areas near the Cordillera Blanca that has left massive amounts of sulphide materials exposed to weathering conditions, oxidizing naturally (ARD processes) and finally contributing to the contamination of the Negro River through faults. In this case, we would face an ARD process in the strict sense, which is the direct oxidation of sulphides outcropping in the upper part of the mountain with the generation of sulphates, the release of hydrogen ions and the consequent generation of acid and the dissolution of the metals. This ARD process would come from the glacial retreat, which, through the faults, transports contaminated water until the spring.

Caracterización citofluorométrica de dos anticuerpos monoclonales específicos de epítopos polimórficos de moléculas HLA de clase I: 30.13.38 (anti-A2, A68, A69) y 29.30.6 (Anti-Bw6) / Cytofluorometric characterisation of two monoclonal antibodies recognising polymorphic epitopes of HLA class I molecules: 30.13.38 (anti-A*02, A*68 and A*69) and 29.30.6 (anti-Bw6)

Hemos caracterizado mediante citometría de flujo los anticuerpos monoclonales frente a moléculas HLA de clase I 30.13.38 y 29.30.6. Nuestros datos previos sobre su reactividad, obtenidos mediante citotoxicidad dependiente de complemento, indicaban que estos anticuerpos eran específicos de HLA-A2+A28, y del epítopo Bw6 portado por algunas moléculas HLA-B, respectivamente. Los experimentos de citometría de flujo mostraron que 30.13.38 reacciona con todos los alelos A*02, A*68 y A*69 disponibles en nuestro laboratorio: A*0201, *0204, *0205, *0207, *0211, *6801, *6802, and *6901. De acuerdo con estos datos, el epítopo diana más probable de 30.13.38 es TTKH (142-145). Por otra parte, el anticuerpo 29.30.6 tiñó con alta intensidad todas las células que expresan alelos con la secuencia asociada a Bw6 ESLRNLRG (76-83). Además, 29.30.6 reconoció con menor afinidad las variantes de esa secuencia que aparecen en B*7301 (VGLRNLRG), B*4601 (VSLRNLRG) y múltiples alelos HLA-C. No obstante, la afinidad de la interacción con estas variantes está por debajo o cerca del umbral de sensibilidad de la tipificación serológica (AU)

Temporal variation of RAPD-PCR phenotype composition of the grain aphid Sitobion avenae (Hemiptera: Aphididae) on wheat: the role of hydroxamic acids.

Hydroxamic acids (Hx) contained in wheat are active mutagens which play an important role in the defence of the plant against aphids. Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) dominant markers were used to assess genetic variability in the aphid Sitobion avenae (Fabricius) in relation to hydroxamic acid levels in their host-plants. Colonies of aphids belonging to a single RAPD-PCR profile were grown on different host-plants differing in their Hx content under greenhouse conditions. The RAPD-PCR phenotypic pattern showed the appearance of two new RAPD-PCR variants after four to five generations of exposure to wheat cv. Chagual (high Hx levels), one after exposure to wheat cv. Huayún (low Hx levels), and none after exposure to oat (lacking Hx). Differential appearance of new RAPD-PCR aphid phenotypes also occurred on field-grown wheat. While the overall phenotypic 'richness' diminished during the season, the number of RAPD-PCR phenotypes decreased on cv. Huayún and increased on cv. Chagual. The preferential appearance in the field and in the greenhouse of new RAPD-PCR phenotypes of S. avenae on cv. Chagual is discussed on the basis of mutagenesis induced by hydroxamic acids and by the products of their transformation within the aphid. Aphid abundance is interpreted in terms of antixenosis and antibiosis by hydroxamic acids. The appearance on cv. Chagual of phenotypes first detected on cv. Huayún was accounted for by intercrop migrations.

Púrpura hipergammaglobulinémica asociada con cirrosis por hepatitis crónica por virus C / Hypergammaglobulinemic purpura associated with chronic hepatitis C and cirrhosis

Se presenta un paciente de 60 años, argentino, con antecedentes de púrpura hipergammaglobulinémica, afectando miembros inferiores y abdomen, desde hace 19 años, con vasculitis leucocitoclástica, factor reumatoideo positivo y crioglobulinemia, asociada con cirrosis por hepatitis crónica por virus C. Es posible que pacientes diagnosticados como púrpura crioglobulinémica estén afectados de hipergammaglobulinas séricas y ambas púrpuras representen una misma enfermedad

Púrpura hipergammaglobulinémica asociada con cirrosis por hepatitis crónica por virus C / Hypergammaglobulinemic purpura associated with chronic hepatitis C and cirrhosis

Se presenta un paciente de 60 años, argentino, con antecedentes de púrpura hipergammaglobulinémica, afectando miembros inferiores y abdomen, desde hace 19 años, con vasculitis leucocitoclástica, factor reumatoideo positivo y crioglobulinemia, asociada con cirrosis por hepatitis crónica por virus C. Es posible que pacientes diagnosticados como púrpura crioglobulinémica estén afectados de hipergammaglobulinas séricas y ambas púrpuras representen una misma enfermedad (AU)

Diagnosis of intestinal amebiasis using salivary IgA antibody detection.

This investigation sought to determine whether detection of salivary IgA antibodies to Entamoeba histolytica could identify intestinal amebic infections among 223 school children. Four groups of children were identified through coproparasitoscopic examination: E. histolytica as other parasites only (20%); and parasite-free (25%). The diagnostic accuracy of salivary IgA antibodies to an E. histolytica membrane extract was 91.5% (sensitivity, 85%; specificity, 98%), maintaining high predictive value at different prevalences. Also, a positive correlation (r = .753, P less than .001) was observed between fecal E. histolytica membrane antigen levels and salivary IgA antibody activity. Measurement of IgA antibodies in saliva may be useful in diagnosing intestinal infections with E. histolytica within a wide range of prevalences. Moreover, sampling of saliva may be a useful non invasive test for immunoepidemiologic surveys.

Evaluation of the ELISA test for detection of Entamoeba histolytica in feces.

The clinical utility of an ELISA test with monoclonal antibodies to detect antigen of Entamoeba histolytica in feces was evaluated in 150 patients with gastrointestinal symptoms. Each subject was examined by rectosigmoidoscopy with rectal smear and/or a triple stool search for ova-bacteria-parasite (OBP); in addition, one stool sample was collected for the ELISA test. All the tests were independent and double blind. E. histolytica was detected by OBP and/or rectosigmoidoscopy in 66 patients; 61 patients had other parasites; and in 23, no parasites were identified. Of all patients, 116 were positive for the ELISA test. Of these, E. histolytica was identified in 52. In 47, other parasites were identified and in 17, no parasites were found. The ELISA test with a monoclonal antibody against E. histolytica antigen showed higher sensitivity than the standard diagnostic methods: the ability to detect the presence of E. histolytica antigen regardless of the destruction of the parasite or of the error due to misidentification of the parasite resulting from faulty preparation of the samples.

An Entamoeba histolytica antigen devoid of enzymatic activity, but endowed with immunogenic and protective properties.

One of the most relevant features of Entamoeba histolytica extracts is their great enzymatic activity. The consequence of this peculiarity is that these extracts digest not only extrinsic proteins but also those within the parasite, causing instability during extract preparation which makes their characterization more difficult and hinders their use in immunoprophylaxis. This report presents evidence which indicates that treatment of E. histolytica extracts with a pH2 acid shock for 30 min at 37 degrees C irreversibly, as shown through its reactivity with polyclonal E. histolytica antisera and through its capacity to induce antibody formation and to protect against intrahepatic challenge with E. histolytica. Among the foremost activities in the field of immunoparasitology are the identification, isolation, purification and characterization of parasite antigens, particularly because of their potential use in immunoprophylaxis. Given the world wide distribution of amebiasis, particularly in undeveloped countries, various researchers have given special importance to the antigenic characterization of the causal agent, Entamoeba histolytica, and to its ability to induce protective immunity in several animal models. Initial studies demonstrated that the parasite produces a variety of proteolytic enzymes which play an important role in the immune response and pathogenesis of the infected host. Additionally, these enzymes cause autodegradation of the amebic extracts, their use in immunoprophylaxis, since proteins germane in inducing protection could be degraded. Even though enzymatic activity may be abolished through specific inhibitors, these are very toxic and therefore not adequate for biological material to be tried on humans.(ABSTRACT TRUNCATED AT 250 WORDS)