Incidencia de hipotiroidismo congénito y fenilcetonuria en una población de recién nacidos vivos de un hospital perinatológico del Gobierno de la Ciudad de Buenos Aires. Años 2000-2004 / Incidence of congenital hypothyroidism and phenylketonurias in a population of alive newborn of a Perinatal Hospital of the Buenos Aires city. 2000-2004

A partir del primero de diciembre del año 2000 se ha implementado la pesquisa universal del hipotiroidismo congenito y fenilcetonuria en los niños nacidos en el Hospital Materno Infantil "Ramón Sardá". Objetivo: Determinar la incidencia de hipotiroidismo congénito y fenilcetonuria en la población de recién nacidos vivos del Hospital Materno Infantil "Ramón Sardá" durante el período 1 de diciembre de 2000 hasta 1 de diciembre de 2004. Material y métodos: Se procedió a la toma de muestra de sangre del recién nacido de término entre las 48 hs y 72 hs posteriores al nacimiento por punción de talón con la tarjeta de Guthrie. Resultados: Desde el 1 de diciembre del 2000 hasta el 1 de diciembre de 2004 se estudiaron 26.219 recién nacidos detectándose: 13 hipotiroidismos congénitos, y una hiperfenilalaninemia persistente (fenilcetonuria o PKU). También se detectaron tres hiperfenilalaninemias transitorias que requirieron tratamiento durante corto tiempo. Los niños a los cuales se les detectó alguna de estas enfermedades inaparentes al nacer fueron tratados tempranamente en el Hospital de Pediatría "Prof. Dr. Juan P. Garrahan". Conclusión: De esta forma se está dando cumplimiento a la Ley Nº 534 sancionada el 30 del año 2000 del Gobierno de la Ciudad Autónoma de Buenos Aires que establece la obligatoriedad de la pesquisa de estas enfermedades en todos los establecimientos públicos, de la seguridad social y privados en el ámbito de la Ciudad de Buenos Aires.

Incidencia de hipotiroidismo congénito y fenilcetonuria en una población de recién nacidos vivos de un hospital perinatológico del Gobierno de la Ciudad de Buenos Aires. Años 2000-2004 / Incidence of congenital hypothyroidism and phenylketonurias in a population of alive newborn of a Perinatal Hospital of the Buenos Aires city. 2000-2004

A partir del primero de diciembre del año 2000 se ha implementado la pesquisa universal del hipotiroidismo congenito y fenilcetonuria en los niños nacidos en el Hospital Materno Infantil "Ramón Sardá". Objetivo: Determinar la incidencia de hipotiroidismo congénito y fenilcetonuria en la población de recién nacidos vivos del Hospital Materno Infantil "Ramón Sardá" durante el período 1 de diciembre de 2000 hasta 1 de diciembre de 2004. Material y métodos: Se procedió a la toma de muestra de sangre del recién nacido de término entre las 48 hs y 72 hs posteriores al nacimiento por punción de talón con la tarjeta de Guthrie. Resultados: Desde el 1 de diciembre del 2000 hasta el 1 de diciembre de 2004 se estudiaron 26.219 recién nacidos detectándose: 13 hipotiroidismos congénitos, y una hiperfenilalaninemia persistente (fenilcetonuria o PKU). También se detectaron tres hiperfenilalaninemias transitorias que requirieron tratamiento durante corto tiempo. Los niños a los cuales se les detectó alguna de estas enfermedades inaparentes al nacer fueron tratados tempranamente en el Hospital de Pediatría "Prof. Dr. Juan P. Garrahan". Conclusión: De esta forma se está dando cumplimiento a la Ley Nº 534 sancionada el 30 del año 2000 del Gobierno de la Ciudad Autónoma de Buenos Aires que establece la obligatoriedad de la pesquisa de estas enfermedades en todos los establecimientos públicos, de la seguridad social y privados en el ámbito de la Ciudad

Participation of the Dengue virus in the fibrinolytic process.

To date, the phatophysiology of hemorrhagic dengue is still unknown and hypotheses which aim to explain the unfortunate cases of the disease (hemorrhagic fever/shock syndrome) are based on epidemiological data and favor the notion of the participation of heterotypic non-neutralizing antibodies during the course of secondary infection (immunologic status of the host). However, cases of hemorrhagic dengue have been reported during the course of primary infections. We propose that the dengue virus, specifically the envelope glycoprotein can participate directly in the installation of the hemorrhagic phenomenon by means of the binding and activation of plasminogen (PLG) as condition previous to the development of the fibrinolytic process. Based on this hypothesis, we evaluated the biological activity of some viral isolates proceeding from hemorrhagic and from dengue fever cases in an in vitro model of fibrinolysis. Dengue isolates were capable of activating PLG. The plasmin generated specifically degraded the fibrin/fibrinogen molecule. This catalytic process can be prevented by the presence of the specific plasmin inhibitor, alpha-2-antiplasmin, for virus isolates from dengue fever, but not for isolates associated with dengue hemorrhagic disease, favoring the exacerbation of the fibrinolytic activity. This new approach allows us to suggest the importance of viral factors in the dengue hemorrhagic fever.

Phylogenetic comparison of the DEN-2 Mexican isolate with other flaviviruses.

Recent attention has focused on the geographic variation of dengue viruses, since major epidemies may follow introduction of a new virus strain into susceptible populations. We cloned and sequenced a very interesting Mexican isolate (200787/1983) which is antigenically unique by signature analysis with respect to all other dengue-2 topotype viruses. This strain is also unique in biological behavior (neurotropism) and is of epidemiological significance in Mexico. The dengue-2 Mexican isolate sequence information was compared with that of other flaviviruses, analyzing the branching structure of the phylogenetic tree reconstructed from the E gene amino acid sequences. The E glycoprotein, is target for neutralizing antibodies and T-cell responses, and defines the tropism and virulence of flaviviruses. In the phylogram, our strain was located in the position of greatest dissimilarity within serotype-2. Also, frequency analysis of amino acids revealed a very different signature pattern from that found in viral serotype-2.

Antiviral effect of flavonoids on the dengue virus.

In the present study we analysed the possible antiviral effect on dengue viruses of different flavonoids extracted and identified at the Chemistry Institute, UNAM, from the Mexican plants Tephrosia madrensis, Tephrosia viridiflora and Tephrosia crassifolia. The flavonoids glabranine and 7-O-methyl-glabranine presented 70% inhibition on the dengue virus at a concentration of 25 microM, while methyl-hildgardtol A, hildgardtol A and elongatine had no effect on viral growth. Our results show that glabranine and 7-O-methyl-glabranine isolated from Tephrosia s.p. exert a dose-dependent inhibitory effect in vitro on the dengue virus.

Experimental amebiasis: molecular weight analysis of Entamoeba histolytica antigens recognized by IgG antibodies.

The reactivity of sera from experimentally infected animal was studied from 5-60 days postinoculation to determine which of the E. histolytica antigens are recognized frequently to infection. Crude extract of E. histolytica trophozoites was used and sera were examined by immunoelectrotransference assay. It was observed that sera recognized polypeptide with 70 kDa molecular mass after 15 days postinoculation onward and later 14 to 24 polypeptide with molecular weight of 110-22 kDa were recognized. All the amebic antigens (polypeptides) could be recognized by sera till 60 days postinoculated animals. Significance of expression of different amebic polypeptides in terms of pathogenesis needs further investigations.

A single nucleotide change in the E protein gene of dengue virus 2 Mexican strain affects neurovirulence in mice.

Eleven clones of dengue virus 2 Mexican strain were selected by the size of their lytic plaques. Nucleotide sequences of the clones producing large plaques (D2ML2, D2ML3 and D2ML4) revealed 11 mutations, 10 of which were silent. The substitution at nucleotide 1168 (G-->C) generates one amino acid difference at residue 390 (Asp-->His) of the envelope protein (E). These clones showed high virulence in suckling mice when inoculated intracerebrally (> or = 70% mortality). However, the clones which showed small lytic plaques (D2MS1, D2MS2 and D2MS4) displayed a substitution from Asp-->Asn at the same position and had attenuated virulence. Based on these data, we suggest that substitution of Asp-->His at residue 390 perhaps affects a functionally important structural element that could be a determinant of dengue neurovirulence. This substitution falls in domain III of the E protein, which plays an important role in viral binding; therefore, we propose that the substitution affects virulence and cellular tropism.

Detection of dengue viral RNA by microplate hybridization.

Dengue virus infection is a major public health problem throughout tropical countries. In endemic areas, dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) are common complications resulting in death. However, serological confirmation of dengue-related illness is often complicated and time-consuming. Detection of dengue viruses in clinical or field samples usually depends on virus isolation in susceptible cell lines or in mosquitoes, followed by viral protein identification using polyclonal or monoclonal antibodies. The increasing incidence of dengue virus infections has prompted increased efforts to develop rapid and reliable diagnostic techniques. A simple microplate hybridization method was developed for identification of viral RNA. Microplate hybridization is simpler than enzyme-linked immunosorbent assay and has several advantages over the conventional dot-blot hybridization method: (1) radioisotopes are not necessary; (2) synthetic oligonucleotide for the probe is not needed; (3) the time required for washing of the solid phase is greatly reduced; and (4) baking is eliminated. The results show that this procedure is sensitive, rapid and easy to perform.

Modifications of the immune response induced by Histoplasma capsulatum products.

To understand the host-parasite relationship in histoplasmosis, mice were inoculated with histoplasmin (HP), the filtrate of aged cultures of Histoplasma capsulatum, and the immune response of these mice towards sheep red blood cells (SRBC) and to trinitrophenyl hapten was studied. The filtrate abrogated completely the primary antibody response to both antigens as measured by the number of spleen hemolytic plaque forming cells when HP was administered at doses greater than 200 micrograms two days before the antigen. Suppression was elicited by HP when it was injected either intravenously, intraperitoneally, or subcutaneously. Inoculation with HP and antigen on the same day did not result in suppression. The secondary antibody response was not modified at any dose. Variation of the response with time was determined by counting the number of rosette forming cells (RFC) to SRBC every two days for a total of 21 days. Antibody-mediated RFC ('B' rosettes) were depressed throughout the experiment, while the number of non 'B', presumably T, RFC did not vary from control values. In animals inoculated with HP alone, high number of RFC were detected on day 11 after HP inoculation, suggesting that HP may have polyclonal activation effects. These results support the possibility that H. capsulatum evades the immune defenses by induction of a suppressive phenomenon in which the afferent limb of the immune response is not involved. This effect appeared to be induced directly by a product of the fungus, instead of by factors generated during the immune response to this microorganism.

Immunomodulation by Histoplasma capsulatum products; polyclonal activation and mitogenic effects.

The presence of reactive spleen cells to sheep red blood cells (SRBC) in nonimmunized BALB/c mice injected with histoplasmin, the culture filtrate of Histoplasma capsulatum, was monitored for 21 days following inoculation. Polyclonal activation, as evidenced by a sharp increase in the number of anti-SRBC rosette-forming cells (RFC), as well as an enhanced response to heterologous non-cross-reactive erythrocytes from other species, was found in the spleens of these rodents on Days 11 to 13. Elimination of B-cell-derived RFC by the addition of complement indicated that the erythrocyte-binding cells consisted of both T- and B-lymphocytes. An immunosuppressive effect was detected if histoplasmin was injected 2 days before the antigen (SRBC), but could be reversed by injecting the filtrate 30 min prior to the antigen, as is found with polyclonal activators displaying immunosuppressive activity. Histoplasmin also had a mitogenic effect on lymphocyte obtained from the spleen, bone marrow, and thymus similar in magnitude to that produced by lipopolysaccharide (LPS) and concanaval in A. The biological significance of these findings is discussed.