Animal welfare evaluation at slaughterhouses for pigs at the "Eje Cafetero" region in Colombia.

Within the insensitization by electronarcosis and the bleeding processes performed at the pig's slaughterhouses, there are some factors that hinder the achievement of an adequate slaughter of these animals, being this a critical phase in which animal welfare must be guaranteed; the objective of this study was to evaluate and compare the efficiency of insensitization by electronarcosis and two types of bleeding direction (horizontal and vertical). Dependent variables were measured as indicators of animal welfare (absence of the corneal reflex, absence of reflex of sensitivity to painful stimuli, attempts to reinstatement or posture recovery and vocalization), after the stunning and bleeding process, in four slaughterhouses of national category in "Eje Cafetero", Colombia. The methodological approach included the binomial distribution, descriptive statistics, hypothesis testing and statistical significance. The results show that the efficiency of the insensitization procedures and type of bleeding direction depends on multiple aspects, including the tranquility of the animals during their handling, the correct position of the insensitization clamps, the amperage used and the time between insensitization and bleeding. In this way, the analysis of possible preventive and/or corrective measures includes: Continuous training and supervision of the personnel in charge of carrying out the procedures, the need to immobilize pigs prior to their insensitization process, the continuous monitoring of process variables and the appropriate vascular cutting that ensures animal's death prior to their entrance into the scalding machine.

La caries dental y los factores relacionados en una población de adultos de la ciudad de la rioja, Argentina / The dental caries and related factors in adult population of the city of rioja, Argentina

La caries dental es un proceso patológico post-eruptivo, localizado, externo, involucra un reblandecimiento de los tejidos duros del diente procediendo a la formación de una cavidad1. Se determinó la presencia de caries dental, su relación con factores patológicos y preventivos en adultos de La Rioja, Argentina. A partir de 183 adultos de 25 a 35 años de edad se estudiaron los dientes con caries, obturaciones, perdidos e índice CPOD y se registraron en una ficha dental. Por cada adulto se obtuvo una historia clínica. El 77% de los adultos presentó un promedio de 3,73±4,28 caries, 4,75±4,61 obturaciones, 1,91±2,92 perdidos e índice CPOD 10,39±5,90. El CPOD para el género femenino fue mayor que para el masculino (p=0,042). La caries se relacionó con bajo nivel de educación (p=0,0001), ingreso económico (p=0,0086), cepillado dental diario (p=0,0340), cepillado nocturno (p=0,0018), con consulta prevalente por dolor (p<0,0001), falta de visita bucal anual (p=0,0003) y de obra social (p=0,0064). La caries dental es una enfermedad presente en la población adulta se asocia con bajo nivel de educación, económico y preventivo dental. Necesita del abordaje económico cultural integrado de la sociedad para mejorar la salud bucal del adulto y asegurar su calidad de vida en su senectud.

The dental caries is defined a post eruptive pathological process of external origin located tooth involves softening of the hard tissues of the tooth proceeding consequently to the formation of a tooth cavity1. The presence of dental caries was determined, its relationship with pathological and preventive factors in adults of La Rioja, Argentina. From 183 adults from 25-35 years of age, were studied decayed, fillings, missing teeth and index DMFT and recorded on a dental chart. For each adult, a clinic history was obtained. The 77% of adults had a mean of 3,73 ±4,28 caries, 4,75 ±4,61 filling, 1,91 ±2,92 missing and DMFT 10,39 ±5,90. The DMFT was higher for the female gender than for males (p=0,042). Caries was associated with low level of education (p=0,0001), low income (p=0,0086) lack tooth daily brushing (p<0,0340), lack of night brushing (p=0,018), check only for pain (p< 0,0001), lack of annual dental visit (p=0,0003) and absence of coverage social (p=0,0064). Dental caries is a disease present in the population of adults, is associated with low level education, economic and lack of prevention dental. Requires a socio cultural economic work of society to improve the oral health of adults and ensure their senescence.

Automation on the generation of genome-scale metabolic models.

Nowadays, the reconstruction of genome-scale metabolic models is a nonautomatized and interactive process based on decision making. This lengthy process usually requires a full year of one person's work in order to satisfactory collect, analyze, and validate the list of all metabolic reactions present in a specific organism. In order to write this list, one manually has to go through a huge amount of genomic, metabolomic, and physiological information. Currently, there is no optimal algorithm that allows one to automatically go through all this information and generate the models taking into account probabilistic criteria of unicity and completeness that a biologist would consider. This work presents the automation of a methodology for the reconstruction of genome-scale metabolic models for any organism. The methodology that follows is the automatized version of the steps implemented manually for the reconstruction of the genome-scale metabolic model of a photosynthetic organism, Synechocystis sp. PCC6803. The steps for the reconstruction are implemented in a computational platform (COPABI) that generates the models from the probabilistic algorithms that have been developed. For validation of the developed algorithm robustness, the metabolic models of several organisms generated by the platform have been studied together with published models that have been manually curated. Network properties of the models, like connectivity and average shortest mean path of the different models, have been compared and analyzed.

Reproductive Response of Ewes Fed with Taiwan Grass Hay (Pennisetum purpureum Schum.) Supplemented with Duckweed (Lemna sp. and Spirodela sp.).

The effect of duckweed (DW) supplementation was evaluated on dry matter intake (DMI), presence and duration of estrus, percentage of ewes repeating estrus and pregnancy rate, as well as the concentration of progesterone (P4) in multiparous crossbred ewes from Pelibuey, Dorper, and Katahdin breeds, fed with Taiwan grass hay (TWH). Eighteen ewes with 39.7±4 kg mean body weight, kept in individual pens, were randomly assigned to one of the following treatments: T1: TWH, T2: TWH plus 200 g DW, T3: TWH plus 300 g DW. The ewes were synchronized with 40 mg fluorogestone acetate (FGA) and 400 UI equine chorionic gonadotropin (eCG). Data were analyzed as a completely randomized design using the GLM procedure. DW supplementation had no effect on dry matter intake (p>0.05); however, a slight decrease of TWH intake was observed as DW supplementation increased. No differences (p>0.05) were found in the beginning of estrus, percentage of ewes presenting it, its duration, or pregnancy rate. There were no differences (p>0.05) on P4 concentration among treatments, or treatmentxperiod interaction (p>0.05). However the period was significant (p<0.01), since the P4 levels increased as time increased after the removal of the FGA device and eCG application.

Distribución espacial de Anopheles pseudopunctipennis en las Yungas de Salta, Argentina / Spatial distribution of Anopheles pseudopunctipennis in the Yungas de Salta rainforest, Argentina

OBJETIVO: Comparar la abundancia de Anopheles pseudopunctipennis, y otros anofelinos, en tres zonas silvestres y modificadas por el hombre, a fin de verificar en qué medida tales diferencias ambientales afectan la distribución espacial de estos mosquitos. MÉTODOS: Se realizaron muestreos mensuales (diciembre de 2001 a diciembre de 2002), con trampas de luz CDC con CO2, en cada sitio de muestreo (selva, borde de selva y peridomicilio). En el peridomicilio, además, dos operadores aspiraron mosquitos posados sobre las paredes. Se estimaron índices de diversidad y abundancia de especies, y se intentó caracterizar a los ambientes estudiados mediante ANOVA, cálculo de cosenos y análisis de agrupamientos. RESULTADOS: Anopheles pseudopunctipennis fue la especie más abundante. Se colectaron también An. argyritarsis, An. nuneztovari, An. rangeli y An. strodei. Excepto An. nuneztovari que no se capturó en el peridomicilio, las demás se colectaron en los tres ambientes. No hubo diferencias en los índices de diversidad, ni tampoco entre los ambientes estudiados; sin embargo, el análisis de agrupamiento separó el borde de la selva, donde todas las especies fueron más abundantes en general. CONCLUSIONES: El borde de la selva fue el ambiente que presentó la mayor abundancia, representando, además del peridomicilio, un ambiente de alto riesgo para la transmisión del paludismo.

Calculating rabies virus neutralizing antibodies titres by flow cytometry.

The determination of the rabies neutralizing antibody (VNA) response after immunization against rabies is an acceptable index of the efficacy of a vaccine and a successful treatment. Several tests have been developed in attempt to improve the assessment of VNA, from mice inoculation to cell-culture fluorescence inhibition tests. All of them, however, present special difficulties in terms of reading or accuracy. The present study describes a neutralization test performed in cell-culture appraised by flow cytometry (FC). Serial dilutions of the serum samples were mixed in vitro with rabies virus before the addition of BHK-21 cells. After 24h-incubation, cells were released by trypsin treatment, fixed and permeabilized with a p-formaldehyde solution and stained with a rabies virus nucleocapsid protein-specific antibody conjugate. The percentage of virus infection inhibition caused by specific antibodies present in the serum were evaluated in a Beckton Dickinson FACSCalibur flow cytometer. A correlation curve between the IU/ml content and the percentage of infective inhibition was built with a reference serum and the VNA titers of serum samples were obtained by extrapolation. Titers obtained by FC and standard test showed an effective pairing results (p < 0.01), with a correlation coefficient (r) = 0.7. These results permit to envisage the FC as a suitable technique to evaluate VNA in sera from immunized animals and likely in human serum samples. Nevertheless, new studies comparing FC to gold-standard techniques are required for determining the FC values of Sensibility and Specificity.

Calculating rabies virus neutralizing antibodies titres by flow cytometry

The determination of the rabies neutralizing antibody (VNA) response after immunization against rabies is an acceptable index of the efficacy of a vaccine and a successful treatment. Several tests have been developed in attempt to improve the assessment of VNA, from mice inoculation to cell-culture fluorescence inhibition tests. All of them, however, present special difficulties in terms of reading or accuracy. The present study describes a neutralization test performed in cell-culture appraised by flow cytometry (FC). Serial dilutions of the serum samples were mixed in vitro with rabies virus before the addition of BHK-21 cells. After 24h-incubation, cells were released by trypsin treatment, fixed and permeabilized with a p-formaldehyde solution and stained with a rabies virus nucleocapsid protein-specific antibody conjugate. The percentage of virus infection inhibition caused by specific antibodies present in the serum were evaluated in a Beckton & Dickinson FACSCalibur® flow cytometer. A correlation curve between the IU/ml content and the percentage of infective inhibition was built with a reference serum and the VNA titers of serum samples were obtained by extrapolation. Titers obtained by FC and standard test showed an effective pairing results (p < 0.01), with a correlation coefficient (r) = 0.7. These results permit to envisage the FC as a suitable technique to evaluate VNA in sera from immunized animals and likely in human serum samples. Nevertheless, new studies comparing FC to gold-standard techniques are required for determining the FC values of Sensibility and Specificity

Fluidized bed design parameters affecting novel lactic Acid downstream processing.

Lactic acid purification was directly done from fermentation utilizing a fluidized bed column refilled with a strong anionic exchange resin. The purpose of this work was to study the influence of two important design parameters, bed-diameter (D) and bed-height (H), in the lactic acid binding and elution capacity of the matrix. By changing the settled bed height from 2.5 to 5 cm for each diameter of column analyzed it was possible to obtain an 50% increase in the binding capacity of the resin in all experiments. This fact was attributed to a higher contact time between the culture broth and the anionic resin produced by the increase of back mixing and lactic acid residence time.

Evaluation of antibodies against a rubella virus neutralizing domain for determination of immune status.

The protective immune responses against rubella virus (RV) are related to its neutralizing epitopes, an issue that is important to consider when assessing the immune status of patients with remote infection. In the present paper, we compare the antibodies detected by a synthetic-peptide-based enzyme immunoassay (EIA) with antibodies detected by the traditional technique of hemagglutination inhibition (HIA) in patients with remote RV infection. The synthetic peptide used as an antigen (SP15) represents a neutralizing epitope that corresponds to amino acids 208 to 239 of the E1 glycoprotein. The SP15-EIA was developed, all variables that affected the assay were standardized, and the test was validated using reference sera. Serum samples (n = 129) from patients with remote RV infection were tested by HIA and SP15-EIA. Discrepant sera were assayed by MEIA (IMX/Abbot). The comparison between HIA and SP15-EIA, taking HIA as the standard methodology for determining immune status, showed that SP15-EIA is very specific and sensitive for detecting protecting antibodies (specificity, 100%; sensitivity, 98.20%). This study demonstrates that antibodies against the neutralizing domain represented by SP15 would be important in the memory response after natural infection and may be a good tool in the determination of the true immune status of patients with remote infection with regard to RV.

Neutralizing monoclonal antibody to the E1 glycoprotein epitope of rubella virus mediates virus arrest in VERO cells.

The best-known mechanism of action of antibody-mediated virus neutralization is to impede the entrance of viruses to host cells, as determined by neutralization assays. Antibodies may also inhibit the exit of rubella virus (RV) from infected host cells; in this case, the interaction of the antibodies with their domains must occur on the plasma membrane, because antibodies cannot enter the cells. In the present study, we were able to block temporally the exit of virions from RV-infected cells by the binding of monoclonal antibody (mAb) H3 to their surface. The objective was accomplished in three steps: first, we determined the duration of the viral replication cycle; then we established the kinetics of the presence of the domains defined by our mAbs in the cytoplasm of RV-infected VERO cells; and, finally, we assessed the release of viral particles to the supernatant of infected VERO cells in the presence or absence of mAbs or positive and negative mice sera. RV-specific mice sera and mAb H3, which binds to the amino acid sequence 208-239 of the RV-E1 glycoprotein, were able to delay for 24 hours the release of virions from infected cultures, suggesting that the reaction of mAb H3 with its epitope may arrest any change necessary for the assembly and/or release of virions. In conclusion, the neutralizing domain recognized by mAb induces antibodies that can block the viral replication by several mechanisms of action, such as the obstruction of virus entry into cells and the delay of viral release. All of these mechanisms are intimately involved in the critical virus-host cell interactions that allow self-limitation of the infection.

Continuous production of L(+)-lactic acid by Lactobacillus casei in two-stage systems.

A two-stage two-stream chemostat system and a two-stage two-stream immobilized upflow packed-bed reactor system were used for the study of lactic acid production by Lactobacillus casei subsp casei. A mixing ratio of D12/D2 = 0.5 (D = dilution rate) resulted in optimum production, making it possible to generate continuously a broth with high lactic acid concentration (48 g l-1) and with a lowered overall content of initial yeast extract (5 g l-1), half the concentration supplied in the one-step process. In the two-stage chemostat system, with the first stage at pH 5.5 and 37 degrees C and a second stage at pH 6.0, a temperature change from 40 degrees C to 45 degrees C in the second stage resulted in a 100% substrate consumption at an overall dilution rate of 0.05 h-1. To increase the cell mass in the system, an adhesive strain of L. casei was used to inoculate two packed-bed reactors, which operated with two mixed feedstock streams at the optimal conditions found above. Lactic acid fermentation started after a lag period of cell growth over foam glass particles. No significant amount of free cells, compared with those adhering to the glass foam, was observed during continuous lactic acid production. The extreme values, 57.5 g l-1 for lactic acid concentration and 9.72 g l-1 h-1 for the volumetric productivity, in upflow packed-bed reactors were higher than those obtained for free cells (48 g l-1 and 2.42 g l-1 h-1) respectively and the highest overall L(+)-lactic acid purity (96.8%) was obtained in the two-chemostat system as compared with the immobilized-cell reactors (93%).

[Presence of Mycoplasma in laboratory cell cultures from Cordoba, Argentina]. / Presencia de micoplasmas en cultivos celulares en laboratorios de la ciudad de Córdoba, Argentina.

In this paper we determined the prevalence of mycoplasma contamination in 17 cell lines. Eighty per cent of the laboratories that currently use cell culture techniques participated in this study. Hoechst 33258 dye was used to detect mycoplasma contamination. The relationship between culture maintenance conditions and the presence of mycoplasma were analyzed, considering the use of antibiotics in the culture media, fetal calf serum (FCS) quality, culture media processing, use of disponsable labware, type of laminar flow cabinet, quantity of operators, and cell culture system. Thirty-five per cent of the analyzed cell lines showed mycoplasma contamination. Those lines belonged to 2 of the 8 surveyed laboratories. When confronting the working conditions versus mycoplasma contamination, 66% of the laboratories that employ non-certified FCS or reuse their labware, show mycoplasma contamination. Mycoplasma presence was found in 50% of the laboratories that use closed culture system, or more than one operator. Laboratories that process their culture media or that include antibiotic in the growing media, show a 40% contamination. The results obtained help to establish working conditions necessary to avoid introducing or spreading the microorganism.

Presencia de micoplasmas en cultivos celulares en laboratorios de la ciudad de Córdoba, Argentina / Mycoplasma presence in cell cultures in laboratories of Cordoba, Argentina

En este trabajo se determinó la presencia de micoplasmas en 17 líneas celulares continuas, provenientes de 8 laboratorios de cultivos celulares que corresponden al 80 por ciento de los que utilizan cultivos celulares en la ciudad de Córdoba. La contaminación fue determinada con el reactivo fluorescente Hoechst 33258. Se analizó la relación entre las condiciones de trabajo de cada laboratorio con la contaminación de sus líneas celulares. Las variables de trabajo estudiadas fueron: uso de antibióticos, calidad del suero fetal bovino (SFB), procesamiento del medio de cultivo, uso de materiales descartables, tipo de cabina de flujo laminar, sistema de crecimiento de cultivo y número de operadores. El índice de contaminación por micoplasmas fue 35 por ciento. De los laboratorios evaluados, sólo dos presentaron contaminación. Al evaluar las condiciones de trabajo en cada laboratorio y relacionarlas con la contaminación por micoplasmas, surgió 66 por ciento de infección entre los laboratorios que utilizaban SFB no certificados o reutilizaban el material de laboratorio; 50 por ciento, entre los laboratorios que contaban con sistemas cerrados de crecimiento celular o con un número de operadores mayor a uno; y 40 por ciento en aquéllos que incluían el procesamiento de los medios de cultivo (filtración o dilución) o utilizaban antibióticos en el medio de crecimiento. Los resultados obtenidos de este análisis contribuyen a sugerir condiciones de trabajo que tiendan a disminuir el riesgo de contaminación

Presencia de micoplasmas en cultivos celulares en laboratorios de la ciudad de Córdoba, Argentina / Mycoplasma presence in cell cultures in laboratories of Cordoba, Argentina

En este trabajo se determinó la presencia de micoplasmas en 17 líneas celulares continuas, provenientes de 8 laboratorios de cultivos celulares que corresponden al 80 por ciento de los que utilizan cultivos celulares en la ciudad de Córdoba. La contaminación fue determinada con el reactivo fluorescente Hoechst 33258. Se analizó la relación entre las condiciones de trabajo de cada laboratorio con la contaminación de sus líneas celulares. Las variables de trabajo estudiadas fueron: uso de antibióticos, calidad del suero fetal bovino (SFB), procesamiento del medio de cultivo, uso de materiales descartables, tipo de cabina de flujo laminar, sistema de crecimiento de cultivo y número de operadores. El índice de contaminación por micoplasmas fue 35 por ciento. De los laboratorios evaluados, sólo dos presentaron contaminación. Al evaluar las condiciones de trabajo en cada laboratorio y relacionarlas con la contaminación por micoplasmas, surgió 66 por ciento de infección entre los laboratorios que utilizaban SFB no certificados o reutilizaban el material de laboratorio; 50 por ciento, entre los laboratorios que contaban con sistemas cerrados de crecimiento celular o con un número de operadores mayor a uno; y 40 por ciento en aquéllos que incluían el procesamiento de los medios de cultivo (filtración o dilución) o utilizaban antibióticos en el medio de crecimiento. Los resultados obtenidos de este análisis contribuyen a sugerir condiciones de trabajo que tiendan a disminuir el riesgo de contaminación (AU)

Presence of a neutralizing domain in isolates of rubella virus in Cordoba, Argentina.

We studied the presence of a neutralizing epitope of rubella virus (RV) in locally circulating strains in Cordoba, Argentina, using binding by the monoclonal antibody (MAb) H3. This epitope is contained in a sequence of the E1 glycoprotein (E1208-239) represented by the synthetic peptide SP15. H3 MAb showed specific binding to SP15 by enzyme-linked immunosorbent assay (ELISA). One wild-type postnatal isolate, four clones derived from this isolate, and one congenital isolate were reactive with H3 by ELISA. These results suggest that the region of RV represented by SP15 is a domain present in locally circulating strains.

Detección de anticuerpos para rubéola en muestras de sangre recolectadas por filtro / Detection of rubella virus antibodies in whole blood collected on filter paper

El síndrome de rubéola congénita (CRS) puede ser fácilmente evitado si las mujeres en edad gestacional conocen su estado inmune y, en caso de ser seronegativas, reciben la vacunación previa al embarazo. Con el objetivo de determinar el estado inmune de grandes poblaciones se adoptó un método sencillo para la recolección y el almacenamiento de las muestras de sangre. A un total de 100 pacientes se les extrajo suero y sangre que fue absorbida en un círculo de papel de filtro, que capta aproximadamente 0,1 ml de suero. Fueron analizados los títulos de anticuerpos inhibidores de la hemaglutinación (TIH). En las muestras de papel, luego de ser almacenada en bolsas plásticas a 25 grados centígrados durante 7, 14, 21, 30, 60 y 100 días, con respecto a los sueros de cada paciente. De las muestras de sangre obtenidas en el papel de filtro a los 30 días de realizada la extracción, el 72 o/o tuvo el mismo TIH y el resto poseía una dilución de diferencia en relación con los sueros correspondientes. De las muestras ensayadas a los 60 días de extracción un 59 o/o tuvo el mismo TIH y el 41 o/o una dilución de diferencia. A los 100 días de extracción, el 51 o/o de las muestras tuvieron el mismo TIH, el 38 o/o una dilución de diferencia y el 11 o/o tuvieon 1 o más de una dilución de diferencia. En conclusión, los resultados de ese estudio mostraron que las muestras de sangre recolectadas sobre papel de filtro pueden ser usadas para la detección de anticuerpos antivirus rubéola determinados por IHA dentro de los 30 días post-obtención con una sensibilidad y especificidad del 100 o/o. Esta muestra en papel es estable a temperatura ambiente, sin ninguna restricción de aire o esterilización especial

Detección de anticuerpos para rubéola en muestras de sangre recolectadas por filtro / Detection of rubella virus antibodies in whole blood collected on filter paper

El síndrome de rubéola congénita (CRS) puede ser fácilmente evitado si las mujeres en edad gestacional conocen su estado inmune y, en caso de ser seronegativas, reciben la vacunación previa al embarazo. Con el objetivo de determinar el estado inmune de grandes poblaciones se adoptó un método sencillo para la recolección y el almacenamiento de las muestras de sangre. A un total de 100 pacientes se les extrajo suero y sangre que fue absorbida en un círculo de papel de filtro, que capta aproximadamente 0,1 ml de suero. Fueron analizados los títulos de anticuerpos inhibidores de la hemaglutinación (TIH). En las muestras de papel, luego de ser almacenada en bolsas plásticas a 25 grados centígrados durante 7, 14, 21, 30, 60 y 100 días, con respecto a los sueros de cada paciente. De las muestras de sangre obtenidas en el papel de filtro a los 30 días de realizada la extracción, el 72 o/o tuvo el mismo TIH y el resto poseía una dilución de diferencia en relación con los sueros correspondientes. De las muestras ensayadas a los 60 días de extracción un 59 o/o tuvo el mismo TIH y el 41 o/o una dilución de diferencia. A los 100 días de extracción, el 51 o/o de las muestras tuvieron el mismo TIH, el 38 o/o una dilución de diferencia y el 11 o/o tuvieon 1 o más de una dilución de diferencia. En conclusión, los resultados de ese estudio mostraron que las muestras de sangre recolectadas sobre papel de filtro pueden ser usadas para la detección de anticuerpos antivirus rubéola determinados por IHA dentro de los 30 días post-obtención con una sensibilidad y especificidad del 100 o/o. Esta muestra en papel es estable a temperatura ambiente, sin ninguna restricción de aire o esterilización especial (AU)

[Detection of rubella antibodies in blood samples collected on filter paper]. / Detección de anticuerpos para rubéola en muestras de sangre recolectadas en papel de filtro.

Congenital rubella syndrome (CRS) could be prevented if young women knew their immune status before pregnancy, contributing in this way to decrease the birth morbidity rate due to CRS among the children. Our objective was to optimize the detection of rubella virus-antibodies by HAI, using an easier and safer method to collect samples of big populations. One hundred specimens, obtained from patients in a pediatric hospital and pregnant women in an institute of Virology were used for this work. Venous blood was drawn and collected in a test tube, and few drops were spotted onto filter paper circles. These samples were kept in envelopes and stored at room temperature until analysis. Seventy two percent of dried blood samples had titers identical to those of the corresponding serum samples, and 28% dried blood samples showed 1 dilution of difference. Storage of dried blood at room temperature for 30 days did not affect the HAI titers. Up to 60 days post attainment, 59% dried blood samples had identical titers to those of the corresponding serum samples, and 41% dried blood samples showed one dilution of difference. At 100 days of storage 51% dried blood samples had identical titers to those of the corresponding serum samples, 38% dried blood samples showed 1 dilution of difference and 11% and more than 1 dilution of difference. In conclusion, dried blood on filter paper is an easier method to transport and store blood samples for the determination of rubella virus immunity, for as long as 30 days. It could be used for large-scale epidemiological studies. The sensitivity and specificity of HAI performed on dried blood samples was 100%. Only 0.25 ml of whole blood is needed and the samples are stable at room temperature, without air or sterile conditioning. The proposed methodology is a practical approach to collect, transport and store blood samples. Moreover the blood dried on paper spots can be placed in a plastic bag and mailed to a reference laboratory. This is an appropriate alternative method for serological screenings in developing countries.

[Isolation of Chlamydia trachomatis and immune response in different populations]. / Aislamiento de Chlamydia trachomatis y respuesta inmune en diferentes poblaciones.

We studied the presence of C. trachomatis-specific IgG and IgM in adults and newborns, respectively, and attempted isolation of the bacteria in cell culture. The determination of antibodies was carried out by an IFA on C. trachomatis infected (L2 434/Bu serotype) McCoy cells, cultured in 24-well plastic plates. We found C. trachomatis-specific IgG in 27% of women with clinical symptoms, in 40% of women being attended for periodic gynecological control, in 60% of infertile women and in 10% of pregnant women. A proportion comparison test revealed the presence of specific IgG as highly significative for the group of infertile women as compared to the group of pregnant women (p < 0.0001). We divided the patients into four groups, in relation to the results of the tests for specific IgG and C. trachomatis isolation. Seven out of 10 had positive isolation and negative IFA, 5 out of 8 had positive isolation and negative IFA. Twenty five out of 28 pregnant women had negative isolation and positive IFA, finally, 63 out of 76 had both tests negative. Statistical analysis using the McNemar proportion-comparison test suggests that IgG's presence is highly significant in pregnant women with respect to other groups (p < 0.001). Our results suggest that the demonstration of IgG is not enough for diagnostic purposes, except in infertile women with a previous history of infection with C. trachomatis. We isolated C. trachomatis in 20% of the newborns tested and 10% were also positive for IgM IFA. The diagnosis was improved by combining both techniques. These results show the importance of the detection of C. trachomatis in youngsters to avoid infertility and in pregnant women to prevent newborn infections and the possibility of premature births and low weight babies.

[The biomass in upflow anaerobic filters]. / El contenido biológico de filtros anaeróbicos de flujo ascendente.

A cylindrical upflow filter packed with non-reticulated polyurethane foam, seeded with anaerobic sewage sludge and geared to biological treatment of dairy industrial wastewater, was used to determine the biomass content of the biofilm and suspended flora. This microflora is responsible for the conversion to methane and carbon dioxide of most of organic matter in wastewater. The methanogenic process reduces the COD of liquid wastes in more than 83% when operate at organic loading rate of 6 Kg COD/m3/d. Sequential sampling showed that biomass could be determined by measurement of volatile solids of each filter section. Those solids are related to filter geometry an produce accumulation of flocs (0.7g/l) in the bottom zone corresponding to liquid inlet.