The elucidation of the life cycle of Saccocoelioides nanii Szidat, 1954 (Digenea: Haploporidae) using molecular techniques.

In South America, the knowledge of trematode diversity parasitizing freshwater fishes is still scarce, as less than 5% of the freshwater fish fauna has been examined for parasites. A similar situation applies to studies on digenean life cycles, which have become increasingly rare. Among the digenean families parasitizing freshwater fishes in the region, Haploporidae is considered the richest in species diversity. However, information about the developmental stages of haploporid life cycles remains fragmentary. Particularly, in Argentina, nine cercariae attributed to the family Haploporidae have been described using morphological analysis, and only two life cycles of this family have been completely elucidated. In this study a new type of cercaria, morphologically assigned to the family Haploporidae and collected from the snail Heleobia parchappii (Cochliopidae) in Los Padres shallow lake, Buenos Aires province, was identified using morphological and molecular techniques. The molecular analysis, based on 28S and ITS2 sequences, revealed that the cercariae were 100% identical to adult specimens of Saccocoelioides nanii (Haploporidae) parasitizing the fish Prochilodus lineatus (Prochilodontidae) from Los Talas, Buenos Aires province. Our results not only provide information about the life cycle of S.nanii but also show that a molecular and morphological approach can be extremely useful in identifying the developmental stages of digeneans and elucidating their life cycles.

Interobserver agreement on the echocardiographic parameters that estimate right ventricular systolic function in the early postoperative period of cardiac surgery. / Acuerdo interobservador de los parámetros ecocardiográficos que estiman la función sistólica del ventrículo derecho en el postoperatorio temprano de cirugía cardiaca.

PRIMARY OBJECTIVE: To know the variability of transthoracic echocardiographic parameters that assess right ventricular systolic function by analyzing interobserver agreement in the early postoperative period of cardiovascular surgery. SECONDARY OBJECTIVE: To assess the feasibility of these echocardiographic measurements. DESIGN: A cross-sectional study, double-blind pilot study was carried out from May 2011 to February 2013. SETTING: Cardiovascular postoperative critical care at the National Institute of Cardiology "Ignacio Chávez", Mexico City, Mexico. PATIENTS: Consecutive, non-probabilistic sampling. Fifty-six patients were studied in the postoperative period of cardiac surgery. INTERVENTION: The first echocardiographic parameters were obtained between 6-8hours after cardiac surgery, followed by blinded second measurements. MAIN VARIABLES: Tricuspid annular plane systolic excursion (TAPSE), tricuspid annular peak systolic velocity on tissue Doppler imaging (VSPAT), diameters and right ventricular outflow area, tract fractional shortening. The agreement was analyzed by the Bland-Altman method, and its magnitude was assessed by the intraclass correlation coefficient (95% confidence interval). RESULTS: Both observers evaluated TAPSE and VSPAT in 48 patients (92%). The average TAPSE was 11.68±4.53mm (range 4-27mm). Right ventricular systolic dysfunction was observed in 41 cases (85%) and normal TAPSE in 7 patients (15%). The average difference and its limits according to TAPSE were -0.917±2.95 (-6.821, 4.988), with a magnitude of 0.725 (0.552, 0.837); the tricuspid annular peak systolic velocity on tissue Doppler imaging was -0.001±0.015 (-0.031, 0.030), and its magnitude 0.825 (0.708, 0.898), respectively. CONCLUSIONS: VSPAT and TAPSE were estimated by both observers in 92% of the patients, these parameters exhibiting the lowest interobserver variability.

BRF1, a subunit of RNA polymerase III transcription factor TFIIIB, is essential for cell growth of Trypanosoma brucei.

RNA polymerase III (Pol III) synthesizes small RNA molecules that are essential for cell viability. Accurate initiation of transcription by Pol III requires general transcription factor TFIIIB, which is composed of three subunits: TFIIB-related factor BRF1, TATA-binding protein and BDP1. Here we report the molecular characterization of BRF1 in Trypanosoma brucei (TbBRF1), a parasitic protozoa that shows distinctive transcription characteristics. In silico analysis allowed the detection in TbBRF1 of the three conserved domains located in the N-terminal region of all BRF1 orthologues, namely a zinc ribbon motif and two cyclin repeats. Homology modelling suggested that, similarly to other BRF1 and TFIIB proteins, the TbBRF1 cyclin repeats show the characteristic structure of five α-helices per repeat, connected by a short random-coiled linker. As expected for a transcription factor, TbBRF1 was localized in the nucleus. Knock-down of TbBRF1 by RNA interference (RNAi) showed that this protein is essential for the viability of procyclic forms of T. brucei, since ablation of TbBRF1 led to growth arrest of the parasites. Nuclear run-on and quantitative real-time PCR analyses demonstrated that transcription of all the Pol III-dependent genes analysed was reduced, at different levels, after RNAi induction.

Quantitative distribution of Salmonella spp. and Escherichia coli on beef carcasses and raw beef at retail establishments.

Salmonella is a foodborne pathogen that commonly inhabits the gastrointestinal tract of a healthy feedlot cattle and can be transferred to the carcass surface during hide removal and evisceration procedures. Numerous investigations on Salmonella prevalence throughout different stages of the beef chain have been conducted. In contrast, limited studies are available on quantitative determinations of Salmonella at different steps in raw meat production. Quantitative data, particularly for pathogenic bacteria such as Salmonella are important for quantitative risk assessment. Salmonella spp. and Escherichia coli populations were enumerated on beef carcass samples collected at abattoirs and also in beef chunks and ground beef samples collected from butcher's shops at retail in Jalisco State, Mexico. Sponge samples from beef carcass sides (n=142) were collected immediately after final water wash and before chilling at three non-federally inspected abattoirs following USDA-FSIS sampling protocols. Beef chunks (n=84) and ground beef (n=65) samples were obtained from 86 butcher's shops. Salmonella enumeration was conducted by the Most Probable Number method and E. coli counts were determined using Petrifilm plates. Salmonella was isolated from 18% of beef carcasses, 39% of beef chunks and 71% of ground beef samples. Salmonella mean counts were 1.3±0.9 Log MPN/300 cm(2) on beef carcasses, 1.9±0.9 and 2.3±1.1 Log MPN/25 g in beef chunks and ground beef samples, respectively. Twenty-six Salmonella serotypes and 11 serogroups were identified among 432 isolates recovered. Salmonella typhimurium (14%), Salmonella sinstorf (12%) and S. Group E1 monophasic (10%) were the most frequent. Escherichia coli was present on 97, 84 and 100% of beef carcasses, beef chunks and ground beef samples, respectively. Escherichia coli mean counts were 3.2±0.7 Log CFU/300 cm(2), 3.9±1.1 and 4.5±1.2 Log CFU/25 g on beef carcasses, beef chunks and ground beef, respectively. Salmonella prevalence and mean counts found in raw beef were higher than previously reported in studies from other countries. The data collected in this study show a trend in the prevalence of Salmonella to be higher as meat processing is extended at retail. This, together with the diversity of serotypes found, indicates that raw meat is exposed to multiple contamination sources during slaughter and retail processing and highlights the necessity to implement Sanitation Standard Operating Procedures for those establishments. Finally, this study provides quantitative information for future risk assessments associated with the risk of human salmonellosis.

Pulmonary hypertension due to acute respiratory distress syndrome

Our aims were to describe the prevalence of pulmonary hypertension in patients with acute respiratory distress syndrome (ARDS), to characterize their hemodynamic cardiopulmonary profiles, and to correlate these parameters with outcome. All consecutive patients over 16 years of age who were in the intensive care unit with a diagnosis of ARDS and an in situ pulmonary artery catheter for hemodynamic monitoring were studied. Pulmonary hypertension was diagnosed when the mean pulmonary artery pressure was >25 mmHg at rest with a pulmonary artery occlusion pressure or left atrial pressure <15 mmHg. During the study period, 30 of 402 critically ill patients (7.46%) who were admitted to the ICU fulfilled the criteria for ARDS. Of the 30 patients with ARDS, 14 met the criteria for pulmonary hypertension, a prevalence of 46.6% (95% CI; 28-66%). The most common cause of ARDS was pneumonia (56.3%). The overall mortality was 36.6% and was similar in patients with and without pulmonary hypertension. Differences in patients' hemodynamic profiles were influenced by the presence of pulmonary hypertension. The levels of positive end-expiratory pressure and peak pressure were higher in patients with pulmonary hypertension, and the PaCO2 was higher in those who died. The level of airway pressure seemed to influence the onset of pulmonary hypertension. Survival was determined by the severity of organ failure at admission to the intensive care unit.

Pulmonary hypertension due to acute respiratory distress syndrome.

Our aims were to describe the prevalence of pulmonary hypertension in patients with acute respiratory distress syndrome (ARDS), to characterize their hemodynamic cardiopulmonary profiles, and to correlate these parameters with outcome. All consecutive patients over 16 years of age who were in the intensive care unit with a diagnosis of ARDS and an in situ pulmonary artery catheter for hemodynamic monitoring were studied. Pulmonary hypertension was diagnosed when the mean pulmonary artery pressure was >25 mmHg at rest with a pulmonary artery occlusion pressure or left atrial pressure <15 mmHg. During the study period, 30 of 402 critically ill patients (7.46%) who were admitted to the ICU fulfilled the criteria for ARDS. Of the 30 patients with ARDS, 14 met the criteria for pulmonary hypertension, a prevalence of 46.6% (95% CI; 28-66%). The most common cause of ARDS was pneumonia (56.3%). The overall mortality was 36.6% and was similar in patients with and without pulmonary hypertension. Differences in patients' hemodynamic profiles were influenced by the presence of pulmonary hypertension. The levels of positive end-expiratory pressure and peak pressure were higher in patients with pulmonary hypertension, and the PaCO2 was higher in those who died. The level of airway pressure seemed to influence the onset of pulmonary hypertension. Survival was determined by the severity of organ failure at admission to the intensive care unit.

Incidence of Salmonella, Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcal enterotoxin in two types of Mexican fresh cheeses.

Handcrafted fresh cheeses are popular among consumers in Mexico. However, unsafe raw materials and inadequate food safety practices during cheese manufacture and preservation make them a potential public health risk. The incidence of Salmonella, Listeria, Escherichia coli O157:H7, and staphylococcal enterotoxin was analyzed in two types of fresh cheese (panela and adobera) commonly marketed in Mexico. A total of 200 samples, 100 panela and 100 adobera, were acquired from 100 wholesale milk product distributors who supply small retailers in the Guadalajara metropolitan area, Jalisco State, Mexico. Pathogens were identified using culture and immunoassay (miniVidas) methods. The presence of staphylococcal enterotoxin was determined by an immunoassay method. Of the 200 analyzed samples, 92 were positive for at least one of the pathogens. The incidence in the panela samples was 56%: 34% Salmonella, 16% E. coli O157:H7, and 6% L. monocytogenes. In the adobera samples, incidence was 36%: 20% Salmonella, 4% E. coli O157:H7, and 12% L. monocytogenes. Staphylococcal enterotoxin was not detected in any of the 200 samples. Choice of technique had no effect on detection of pathogen incidence, although the immunoassay method identified more Salmonella serotypes than the culture method. Handcrafted panela and adobera fresh cheeses in Mexico frequently contain pathogenic bacteria and therefore pose a public health risk.

Niveles séricos del antígeno prostático específico (PSA) dentro de la campaña de prevención del cáncer de próstata / Serum levels of the prostate-specific antigen (PSA) in the prostate cancer prevention campaign

La determinación del antígeno prostático específico (PSA) forma parte del diagnóstico del cáncer de próstata. Como en condiciones patológicas sus niveles aumentan, es considerado marcador tumoral útil de diagnóstico de cáncer de próstata en forma precoz. Determinamos los niveles séricos de PSA, dentro de la campaña “Semana de la Próstata” organizado por la Cátedra de Urología del Hospital de Clínicas en Octubre 2007. De los 89 pacientes, el 86,5% presentó niveles de PSA entre 0 y 4ng/ml, 10,1% entre 4 y 10 ng/ml y el 3,4% entre 10 y 40 ng/ml respectivamente. Se realizó una distribución por edad y se determinaron las medias de los valores de PSA en los mismos. El 12,4% del grupo E1 (41 a 50 años) con 0,5ng/ml de PSA, el 52,8% del grupo E2 (51 a 60 años) con 7,4ng/ml de PSA, el 28,1% del grupo E3 (61 a 70 años) con 5,2ng/ml de PSA y el 6,7% del grupo E4 (71 a 80 años) con 1,5 ng/ml de PSA. Hallándose valores más elevados de PSA en el grupo E2 y E3, no así en el grupo E4. En relación al tacto rectal (TR) y los valores del PSA, el 31,5%(28) presentaron TR normal con un valor medio de PSA de 3,4. Mientras que el 65,1% (58) presentaban TR patológico con valores medios de PSA de 7,17 en 55 pacientes y sólo 3 pacientes con TR patológico presentaron niveles de PSA por debajo de 2,5 ng/ml. El TR resultó ser la variable con mayor poder de discriminación, con respecto al resultado de PSA en estos pacientes.

The determination of prostate-specific antigen (PSA) is part of the diagnosis of prostate cancer.It is considered an useful tumor marker for early diagnosis of porostate cancer because in pathological conditions its levels increase.Serum levels of PSA were determined within the campaign "Prostate Week" organized by the Department of Urology of the Hospital de Clínicas in October 2007.;Of the 89 patients, 86.5% had PSA levels between 0 and 4 ng/ml, 10.1% between 4 and 10 ng/ml and 3.4% between 10 and 40 ng/ml respectively. An age distribution was made and the mean of PSA values were determined in each group. Twelve point four percent of group E1 (41 to 50 years) had 0.5 ng/ml of PSA, 52.8% of group E2 (51 to 60 years) 7.4 ng/ml PSA, 28.1% of E3 group (61 to 70 years) 5.2 ng/ ml of PSA and 6.7% of the E4 group (71 to 80 years) had 1.5 ng/ml of PSA.The highest values of PSA were found in E2 and E3 groups, but not in the E4 group. In relation to digital rectal examination (DRE) and PSA values, 31.5% (28) showed normal DRE with a mean value of PSA of 3.4 while 65.1% (58) had pathological DRE with mean values of PSA of 7.17 in 55 patients and only 3 patients had pathological TR with PSA levels below 2.5 ng/ml. The DRE was the variable with the greatest ability to discriminate in relation to the results of PSA in these patients.

Improved method for in vitro secondary amastigogenesis of Trypanosoma cruzi: morphometrical and molecular analysis of intermediate developmental forms.

Trypanosoma cruzi undergoes a biphasic life cycle that consists of four alternate developmental stages. In vitro conditions to obtain a synchronic transformation and efficient rates of pure intermediate forms (IFs), which are indispensable for further biochemical, biological, and molecular studies, have not been reported. In the present study, we established an improved method to obtain IFs from secondary amastigogenesis. During the transformation kinetics, we observed progressive decreases in the size of the parasite body, undulating membrane and flagellum that were concomitant with nucleus remodeling and kinetoplast displacement. In addition, a gradual reduction in parasite movement and acquisition of the amastigote-specific Ssp4 antigen were observed. Therefore, our results showed that the in vitro conditions used obtained large quantities of highly synchronous and pure IFs that were clearly distinguished by morphometrical and molecular analyses. Obtaining these IFs represents the first step towards an understanding of the molecular mechanisms involved in amastigogenesis.

Relación entre los niveles de ácido fólico, vitamina B12 y homocisteína materna y los defectos de tubo neural y labio hendido / Relation between levels of folic acid, vitamin B12 and maternal homocysteine with neural tube defects and cleft lip

El objetivo del trabajo fue determinar la asociación entre los niveles de ácido fólico, vitamina B (Vit B12) y homocisteína (Hci) maternos, con defectos del tubo neural (DTN) y labio hendido (LH) con y sin paladar hendido (c/s PH). Se realizó un estudio tipo casos y controles. Casos, con diagnóstico de DTN y LH c/s PH (n=36) y cuatro controles hospitalarios por caso (n=141). Se incluyeron recién nacidos (RN) y lactantes hasta 12 meses de edad. Las variables de pareamiento fueron: edad del RN o lactante, etnia y hospital. Un 23 por ciento de etnia Tarahumara y 77 por ciento mestizos. Se determinó ácido fólico intraeritrocitario (AFI), plasmático (AFP) y Vit B12 por radioinmunoensayo, la Hci por inmunoensayo de fluorescencia polarizada. Se consideró deficiencia si el AFI fue <160 ng/mL, AFP <3.5 ng/ mL y la Vit B12 <200 pg/mL e hiperhomocisteinemia, si Hci >15 J.mol/L. El análisis estadístico se realizó a través de regresión logística condicionada. Se identificó deficiencia de AFI en el 22 por ciento de las mujeres cuyos recién nacidos o lactantes presentaron algún tipo de defecto congénito y en el 12 por ciento de los controles. La relación entre AFI y DTN, LH c/s PH ajustada por edad materna, exposición a plaguicidas y zona de residencia fue RM 2,96 (IC 95 por ciento 0,92-9,46). No se encontraron diferencias en los niveles de Hci ni de Vit B12. Conclusiones: Nuestros resultados sugieren que RN cuyas madres cursan con una deficiencia de AFI tienen mayor riesgo de presentar DTN y LH c/s PH.

Objective: To determine the association between maternal folate deficiency, neural tube defects (NTDs), and cleft lip, with and without cleft palate (CL/P). Material and methods: A case/control study was conducted. The cases included subjects with diagnoses of NTD and CL/P (n=36) and four hospital controls per case (n=141); the study included newborns (NBs) and nursing babies up to 12monthsof age. The parameter variables were the following: the age of the NB or nursing baby, the ethnic group, and the hospital of origin. The Tarahumara ethnic group made up 23 percent of the cases, while 77 percent were mestizos. The red cell folate (RCF), the plasma folie acid (PFA), and the vitamin B12 levels were determined by radioimmunoassay and the homocysteine levels by polarized fluorescence immunoassay. A deficiency was considered to be present if the RCF were <160 ng/mL, the PFA <3.5 ng/mL and the vitamin B <200 pg/ mL; hyperhomocysteinemia was defined as HC >15 J,mol/L. The statistical analysis was carried out through of conditional logistic regression. Results: An RCF deficiency was identified in 22 percent of the women whose newborn or nursing babies presented with some type of congenital defect and in 12 percent of the controls. The correlation adjusted by maternal age, exposure to pesticides and zone of residence was OR 2.96 (CI 95 percent 0.92-9.46). There was no difference in vitamin B12 or homocysteine levels between groups. Conclusions: Our results suggest that newborns whose mothers present with an RCF deficiency have an increased risk of displaying NTD and CL/P.

Isolation of Arcobacter spp. from retail meats and cytotoxic effects of isolates against vero cells.

A survey of Arcobacter spp. was conducted over a 12-month period in Guadalajara, Mexico. A total of 135 samples (45 lean ground beef samples, 45 lean ground pork samples, and 45 chicken samples, including drumsticks, gizzards, and ground or chopped breast) were collected from local butcheries. The samples were enriched in Johnson-Murano enrichment medium and then streaked onto Johnson-Murano agar plates. Typical colonies were subjected to microscopic and biochemical identification followed by polymerase chain reaction confirmation of the genus Arcobacter. All isolates confirmed to be Arcobacter isolates were then inoculated into Eagle's minimum essential medium to determine their cytotoxicity against Vero cells. Arcobacter spp. were detected in 28.8, 51.1, and 40.0% of beef, pork, and chicken samples, respectively. From these samples, 101 isolates were confirmed to be Arcobacter spp. by polymerase chain reaction. Overall, the species most frequently identified was A. butzleri, followed by A. skirrowii. A. cryaerophilus was isolated only from pork meat. Ninety-five (95%) of the Arcobacter isolates produced a virulence mechanism against Vero cells, and 38 of them induced cell elongation, indicating enterotoxin production. Eighteen isolates produced the formation of vacuoles, and 39 produced both vacuolization and elongation. The vacuolization effect may be related to a vacuolizing toxin. The production of a vacuolizing toxin by Arcobacter spp. has not previously been reported. Results obtained in this study indicate that Arcobacter spp. may show cytotoxic effects other than the recognized enterotoxin production.

[Development of a canine model of chronic progressive right ventricular hypertension]. / Desarrollo de un modelo canino de hipertensión ventricular derecha crónica progresiva.

INTRODUCTION: Several animal models of right ventricle hypertension (RVH) have been produced through pulmonary artery banding with linen, tygon or teflon. Nevertheless few devices attempting a progressive, step by step graduated chronic development of RVH have been reported. The present study describes the results in our animal model of chronic RVH. MATERIAL AND METHODS: We designed a software programmed to obtain hemodynamic data and installed a small occlusive hydraulic device (OHD) at the pulmonary artery trunk producing a raise in the right ventricular systolic pressure (RVSP); this pressure can be modified externally through the OHD. We studied 12 healthy mongrel dogs (18 to 28 kg of weight) in the course of 6 months. Hemodynamic measurements were performed at different RVSP at two months intervals; (Baseline, 40 mmHg and 60 mmHg). RESULTS: The software was useful to analyze several hemodynamic variables at each RVSP. At 60 mmHg, the end diastolic pressure of the right ventricle (RVEDP) increased from 4.2 +/- 0.4 mmHg to 13.2 +/- 1.1 mmHg, p < 0.000, accompanied with a fall in cardiac output adjusted to the dogs weight from 0.16 +/- 0.03 L/min/kg to 0.09 +/- 0.01 L/min/kg, p > 0.000. Also an increase of the end diastolic pressure of the left ventricle (LVEDP) from 7.4 +/- 0.8 mmHg to 16.3 +/- 2.8 mmHg, p < 0.000, was observed. RVSP was maintained in chronic condition and the intraclass correlation coefficient was 0.83, P < 0.005. CONCLUSIONS: Right ventricular chronic hypertension is created. The device is useful and reliable to maintain chronic increments of RVSP. The software permits a versatile analysis.