Antigen incorporation on Cryptosporidium parvum oocyst walls

Cryptosporidium parvum oocysts are the infective stages responsible for transmission and survival of the organism in the environment. In the present work we show that the oocyst wall, far from being a static structure, is able to incorporate antigens by a mechanism involving vesicle fusion with the wall, and the incorporation of the antigen to the outer oocyst wall. Using immunoelectron microscopy we show that the antigen recognized by a monoclonal antibody used for diagnosis of cryptosporidiosis (Merifluor®, Meridian Diagnostic Inc.) could be found associated with vesicles in the space between the sporozoites and the oocysts wall, and incorporated to the outer oocyst wall by an unknown mechanism.

Análisis de supervivencia post-trasplante hepático por Cirrosis post-hepatitis C en pacientes coinfectados VIH/VHC, en comparación con monoinfectados por VHC.

La TARGA (terapia antirretroviral de gran activitat) ha camviat el pronóstic dels pacients infectats pel VIH. Actualment la cirrosi per VHC y el hepatocarcinoma son les principales causes de mort. El trasplantament hepátic (TH) es una indicació recent en aquests pacients. Objectius: Comparar la supervivència post-TH en pacients coinfectats VHC/VIH front a monoinfectats VHC. Conclusions: Els resultats preliminars en el nostre centre son inferiors en pacients coinfectats en comparació amb els controls, que podría ser degut a contraindicacions para el tractament antiviral i a una menor eficacia del mateix.

Hepatitis C prevalence and risk factors in hemodialysis patients in Central Brazil: a survey by polymerase chain reaction and serological methods

An hemodialysis population in Central Brazil was screened by polymerase chain reaction (PCR) and serological methods to assess the prevalence of hepatitis C virus (HCV) infection and to investigate associated risk factors. All hemodialysis patients (n=428) were interviewed in eight dialysis units in Goiânia city. Blood samples were collected and serum samples screened for anti-HCV antibodies by an enzyme-linked immunosorbent assay (ELISA). Positive samples were retested for confirmation with a line immunoassay (LIA). All samples were also tested for HCV RNA by the PCR. An overall prevalence of 46.7% (CI 95%: 42-51.5) was found, ranging from 20.7% (CI 95%: 8.8-38.1) to 90.4% (CI 95%: 79.9-96.4) depending on the dialysis unit. Of the 428 patients, 185 were found to be seropositive by ELISA, and 167 were confirmed positive by LIA, resulting in an anti-HCV prevalence of 39%. A total of 131 patients were HCV RNA-positive. HCV viremia was present in 63.5% of the anti-HCV-positive patients and in 10.3% of the anti-HCV-negative patients. Univariate analysis of risk factors showed that the number of previous blood transfusions, transfusion of blood before mandatory screening for anti-HCV, length of time on hemodialysis, and treatment in multiple units were associated with HCV positivity. However, multivariate analysis revealed that blood transfusion before screening for anti-HCV and length of time on hemodialysis were significantly associated with HCV infection in this population. These data suggest that nosocomial transmission may play a role in the spread of HCV in the dialysis units studied. In addition to anti-HCV screening, HCV RNA detection is necessary for the diagnosis of HCV infection in hemodialysis patients.

A New Approach for Bounding Awards in Bankruptcy Problems

The solution for the ‘Contested Garment Problem’, proposed in the Babylonic Talmud, suggests that each agent should receive at least some part of the resources whenever the demand overcomes the available amount. In this context, we propose a new method to define lower bounds on awards, an idea that has underlied the theoretical analysis of bankruptcy problems from its beginning (O’Neill, 1982) to present day (Dominguez and Thomson, 2006). Specifically, starting from the fact that a society establishes its own set of ‘Commonly Accepted Equity Principles’, our proposal ensures to each agent the smallest amount she gets according to all the admissible rules. As in general this new bound will not exhaust the estate, we analyze its recursive application for different sets of equity principles. Keywords: Bankruptcy problems, Bankruptcy rules, Lower bounds, Recursive process

Interleukin-4 production in BALB/c mice immunized with Anisakis simplex

We investigated the interleukin (IL-4) levels in BALB/c mice immunized with Anisakis extract in single or multiple doses and in mice orally infected with a larva. From animals immunized maximum responses were obtained with the multiple doses with an only IL-4 peak. Conversely, in the mice inoculated with a larva per os, the IL-4 levels showed two peaks of different rates.

In Vitro and in Vivo Assays of 3,5-Disubstituted-Tetrahydro-2H-1,3,5-Thiadiazin-2-Thione Derivatives against Trypanosoma cruzi

Cytotoxicity assays of 24 new 3,5-disubstituted-tetrahydro-2H-1,3,5-thiadiazin-2-thione derivatives were performed. The 17 compounds with higher anti-epimastigote activity and lower cytotoxicity were, thereafter, screened against amastigote of Trypanosoma cruzi. Out of these 17 derivatives S-2d was selected to be assayed in vivo, because of its remarkable trypanocidal properties. To determine toxicity against J774 macrophages, a method based on quantification of cell damage, after 24 h, was used. Cell respiration, an indicator of cell viability, was assessed by the reduction of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] to formazan. Anti-amastigote activity was estimated after 48 h by microscopic counts of May Grünwald-Giemsa-stained monolayers. Nifurtimox and benznidazole were used as reference drugs. For the in vivo experiences, mice were infected with 10(4) blood trypomastigotes and then treated during 15 days with S-2d or nifurtimox by oral route. All of the compounds were highly toxic at 100 µg/ml for macrophages and a few of them maintained this cytotoxicity even at 10 µg/ml. Of the derivatives assayed against amastigotes 3k and S-2d showed an interesting activity, that was held even at 1µg/ml. It is demonstrated that the high anti-epimastigote activity previously reported is mainly due to the non-specific toxicity of these compounds. In vivo assays assessed a reduction of parasitemia after administration of S-2d to infected mice.

Estudio comparativo de los valores de difusión por RM de las radiaciones ópticas en pacientes diagnosticados de síndrome clínico aislado con pacientes controles.

Diversos estudis han demostrat que, en pacients amb esclerosi múltiple, existeixen alteracions als paràmetres de difusió mesurats amb Resonància Magnètica als tractes de substància blanca que es mostren aparentment normals en les seqüències convencionals. Amb l’objectiu de demostrar si aquestes alteracions apareixen precoçment en la fase de síndrome clínic aïllada, es van analitzar una sèrie d’estudis de Resonància Magnètica cerebral amb seqüències potenciades en difusió i tractografia de les radiacions òptiques, de pacients amb el diagnòstic de síndrome clínic aïllada i pacients controls, mesurant en tots ells els valors dels paràmetres principals de difusió: coeficient de difusió aparent y fracció d’anisotropia. Amb aquestes exploracions no es van demostrar alteracions als paràmetres de difusió en fases tan precoces de la malaltia als pacients casos davant els controls.

Protocolo diagnóstico y seguimiento de la prevalencia e incidencia del virus del papiloma humano (vph) y las anormalidades citológicas de la mucosa anal de hombres que tienen sexo con hombres (hsh) e infección por el virus de la inmunodeficiencia humana (vih).

La citologia anal és un mètode sensible en el despistatge de la neoplàsia de canal anal i similar a la biòpsia dirigida mitjançant rectoscopi i tinció amb àcid acètic al 5%, sobretot en lesions d’alt grau de malignitat; a més de ser una prova adequada en el seguiment d’aquestes lesions. Els pacients VIH homes que tenen sexe amb altres homes tenen major incidència i prevalència de virus papiloma humà i major nombre d’anormalitats en la mucosa del canal anal que els VIH negatius.

Comparison of a Recombinant-antigen Enzyme Immunoassay with Treponema pallidum Hemagglutination Test for Serological Confirmation of Syphilis

A recombinant-antigen enzyme immunoassay (EIA), BioSCREEN TM anti-Treponema pallidum, was compared favorably with the T. pallidum hemagglutination test, in the detection of specific antibodies in different groups of sera from patients with primary (n = 38), secondary (n = 10), early latent (n = 28) and congenital syphilis (n = 2), patients with leptospirosis ( n= 8), infectious mononucleosis (n = 7), hepatitis (n = 9), diabetes mellitus (n = 11), rheumatoid arthritis (n = 13), leprosy (n = 11), tuberculosis (n = 9), HIV/Aids ( n= 12), systemic lupus erythematosus (n = 4), rheumatic fever (n = 3), old-persons (n = 9), pregnant women (n = 29) and blood donors (n = 164). The coincidence between them was 95.1%. The sensitivity and specificity of the EIA were 93.3% and 95.5%, respectively. Fifteen serum specimens belonging to old-persons, pregnant women, blood donors, and patients with human leptospirosis, hepatitis, diabetes mellitus, tuberculosis and rheumatic fever gave false-positive results by Venereal Disease Research Laboratory and/or Rapid Plasma Reagin. The EIA can be used as alternative method for the serological confirmation of syphilis.

IgM-Immunofluorescence Test as a Diagnostic Tool for Epidemiologic Studies of Schistosomiasis in Low Endemic Areas

The high sensitivity and the ability to diagnose schistosomiasis in a very early phase after infection have indicated the detection of IgM antibodies to Schistosoma mansoni gut antigens by the immunofluorescence test (IgM-IFT) as a useful serological test for epidemiological studies in low endemic areas. When applied in a follow-up study for two years, higher rates of seroconversion from IFT negative to positive were observed during the summer months, suggesting seasonal transmission of schistosomiasis in the rural area of the municipality of Itariri (São Paulo, Brazil). In each survey, blood samples from about 600 schoolchildren were collected on filter paper and submitted to IgM-IFT. When the blood samples were classified for the IgM antibody levels, according to the intensity of fluorescent reaction observed at fluorescence microscopy, and correlated to the egg counts in the Kato-Katz positive patients, no association was observed. This observation might suggest that the intensity of fluorescence observed in the IgM-IFT, as an indicator of IgM antibody levels, could not be an useful seroepidemiological marker for classifying areas of low endemicity according to degrees of infection.

In Vitro and in Vivo Anti-Trypanosoma cruzi Activity of a Novel Nitro-derivative

Nitroarylidenemalononitriles and their cyanoacetamide derivatives with remarkable anti-epimastigote properties, were synthesized attempting to obtain new 3,5-diamino-4-(5'-nitroarylidene)-4H-thiadiazine 1,1-dioxide derivatives, which in previous reports had shown anti-Trypanosoma cruzi activity. Tests to evaluate the cytotoxicity of compounds were performed on J774 macrophages. 5-nitro-2-thienyl-malononitrile (5NO2TM), was the only product which maintained a high anti-epimastigote activity at concentrations in which it was no longer cytotoxic, thus it was assayed against intracellular amastigotes. Its anti-amastigote activity was similar to that of nifurtimox. Afterwards in vivo toxicity and anti-chagasic activity were determined. A reduction in parasitemia was observed.

Assessment of Therapeutic Response of Plasmodium vivax and Plasmodium falciparum to Chloroquine in a Malaria Transmission Free Area in Colombia

In order to determine the frequency of therapeutic failures to chloroquine (CQ) in patients with malaria due to either Plasmodium falciparum or P. vivax, and to explore the usefulness of a malaria-free city as a sentinel site to monitor the emergence of drug resistance, 53 patients (44 infected with P. vivax and 9 with P. falciparum) were evaluated at the Laboratory of Parasitology, Universidad del Valle in Cali, Colombia. Patients received 25 mg/kg of CQ divided in three doses over 48 h; they were followed during 28 days according to WHO/PAHO protocols. While therapeutic failures to CQ in the P. vivax group were not detected, the proportion of therapeutic failures in the P. falciparum group was high (78%) and consistent with the reports from endemic areas in Colombia. The diverse origin of cases presenting therapeutic failure confirmed that P. falciparum resistant to CQ is widespread in Colombia, and further supports the change in the national antimalarial drug scheme. Monitoring of drug resistance in malaria free areas would be useful to identify sites requiring efficacy evaluation, and in some situations could be the most appropriate alternative to collect information from endemic areas where therapeutic efficacy studies are not feasible.

Ultrastructure of Proechinophthirus zumpti (Anoplura, Echinophthiriidae) by scanning electron microscopy

The ultrastructure of Proechinophthirus zumpti Werneck, 1955, mainly the external chorionic features of the egg, is described through electronic microscopy techniques. This species was first cited in Argentina, infesting Arctocephalus australis (Zimmermann, 1873). The morphological adaptations of adults and nymphs are described in both species of Proechinophthirus parasitic on Otariidae: P. fluctus (Ferris, 1916) and P. zumpti.

Supervivencia y factores pronósticos en una serie de 317 pacientes con esclerodermia

La esclerosis sistèmica és una malaltia del teixit conectiu que té una gran variabilitat a la seva expressió y evolució clíniques. El càlcul de la supervivència dels malalts no ofereix resultats uniformes als diferents estudis realitzats. En aquest treball estudiem la supervivència i factors de risc associats al pronòstic a 317 pacients espanyols amb ES controlats en un únic hospital universitari. Tal i com mostra aquest estudi la supervivència a l´esclerodermia ha aumentat a la última dècada, essent la principal causa de mort a l´actualitat l´afecció pulmonar. Segons aquest treball, són factors de risc associats a una major mortalitat: l´afecció pulmonar, la forma difusa, la crisis renal esclerodèrmica i l´edat superior als 60 anys al moment del inici de la malaltia.

Effects of chloroquine and sulfadoxine/pyrimethamine on gametocytes in patients with uncomplicated Plasmodium falciparum malaria in Colombia

The effect of antimalarials on gametocytes can influence transmission and the spread of drug resistance. In order to further understand this relationship, we determined the proportion of gametocyte carriers over time post-treatment in patients with uncomplicated Plasmodium falciparum malaria who were treated with either chloroquine (CQ) or sulfadoxine/pyrimethamine (SP). The overall proportion of gametocyte carriers was high (85%) and not statistically significantly different between the CQ and SP treatment groups. However, an increased risk of carrying gametocytes on day 14 of follow up (1.26 95% CI 1.10-1.45) was found among patients having therapeutic failure to CQ compared with patients having an adequate therapeutic response. This finding confirms and extends reports of increased risk of gametocytaemia among CQ resistant P. falciparum.