Peabody Picture Vocabulary Test-III: Normative data for Spanish-speaking pediatric population.

OBJECTIVE: To generate normative data for the Peabody Picture Vocabulary Test-III (PPVT-III) in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Honduras, Guatemala, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the PPVT-III as part of a larger neuropsychological battery. PPVT-III scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models showed main effects for age in all countries, such that scores increased linearly as a function of age. In addition, age2 had a significant effect in all countries, except Guatemala and Paraguay. Models showed that children whose parent(s) had a MLPE >12 years obtained higher scores compared to children whose parent(s) had a MLPE ≤12 years in all countries, except for Cuba, Peru, and Puerto Rico. Sex affected scores for Chile, Ecuador, Guatemala, Mexico, and Spain. CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate interpretation of the PPVT-III when used in pediatric populations.

Phenol determination by an amperométrico biosensor based on lyophilized mushroom (Agaricus bisporus) tissue.

A simple and inexpensive biosensor based on lyophilized mushroom tissue (Agaricus bisporus) was developed for amperometric determination of phenol. This fungi tissue contains tyrosinase (EC 1.14.18.1) enzyme that catalysis two sequential oxidation reactions with phenolic substrates. Both reactions involve molecular oxygen; therefore, the commercial Clark-type oxygen electrode was selected as a transducer. The lyophilized biocomponent was tested in two different forms: cubes (at two positions in the biosensor system) or powder. In characterization studies of the biosensor, some parameters such as time reaction, linear range and repeatability were investigated. For the best biosensor configuration, a linear response was observed from 0.1 to 10.0mg L(-1) phenol; variation coefficient and standard deviation were calculated as 0.02% and +/- 0.11mg L(-1), respectively.

Development of an amperometric biosensor for phenol detection.

With the aim of searching for an in situ method for monitoring phenol, Agaricus bisporus tissue with tyrosine activity was used as a biocomponent and an oxygen electrode used as a transducer to develop a biosensor. The experimental methodology investigated the relation between dissolved oxygen and phenol concentration using a standard solution. Biosensor calibration was evaluated by studying reaction time and tissue amount necessary to promote a reliable response and to minimize errors. The influence of air saturation of the sample and washing of the electrode was also investigated. Results showed that 5 g of mushroom tissue with a 1 min reaction time promoted the best biosensor response within a phenol concentration range of 5-10 ppm. Washing of the electrode did not change the performance of the analysis; however, initial air saturation caused less variation amongst the samples.

Agaricus bisporus as a source of tyrosinase for phenol detection for future biosensor development.

Phenols are toxic compounds that are present in several industrial wastewaters, so their quantification has great environmental importance. In order to permit an analytical methodology for in situ monitoring, this work aims to study the application of Agaricus bisporus tissue as a source of tyrosinase and the optimum reaction conditions for the development of a phenol biosensor. Such an enzyme is a polyphenol oxidase that transforms many different phenolic compounds into quinones. Experiments with fungi tissue were performed to evaluate different sizes of tissue (0.5, 1.0 and 1.5 cm), different temperatures (23.5 degrees C to 60 degrees C), and different pH values (6, 7 and 8) to quantify analytically phenol content. Amongst the tested conditions, those that had presented larger efficiency in phenol oxidation were attained with the fungal tissue size of 1 cm, at pH 8.0, in the temperature range from 35 degrees C to 45 degrees C.

First-trimester pregnancy loss and active Chlamydia trachomatis infection: correlation and ultrastructural evidence.

The incidence of Chlamydia trachomatis (Ct) infection and the possible correlation between couples presenting with first-trimester spontaneous abortions and active Ct infection was assessed. Additionally, the ability of Ct to infect zona-free hamster oocytes was explored by incubating the oocytes with spermatozoa from infected patients. A total of 961 women and 750 men consulting our reproductive medicine centre were screened for Ct using direct immunofluorescence. The general incidence of Ct infection was 9.4% in females (90 of 961) and 13.9% in males (104 of 750). In women with spontaneous abortions the incidence of Ct was 21.0% (14 of 66) compared with 8.9% (23 of 59) for women without spontaneous abortions and term pregnancies (chi-square, P < 0.05). When both partners of the couples were considered (one or both partners infected), the incidence rose to 68.8% (22 of 32) (chi-square, P < 0.001). In vitro studies using electron microscopy demonstrated the presence of Ct on the surface of and inside the oocyte. These results indicate a correlation between an active Ct infection and spontaneous abortion. Electron microscopy studies suggested the possibility of direct oocyte infection by Ct. Two models are proposed for the pathogenesis of Ct-related early abortions: (i) direct zygote infection, and (ii) immune response to heat shock proteins expressed by the zygote and triggered by previous Ct infections.

Chlamydia trachomatis infection in male partners of infertile couples: incidence and sperm function.

Chlamydia trachomatis infection is one of the most common sexually transmitted diseases. Its effect on male fertility, however, is still controversial. In this study, 284 male partners of infertile couples consulting the Center of Studies in Reproductive Biology (CEBRE) were analyzed. The incidence of C. trachomatis infection among male partners of infertile couples was 38.6%. There were no significant differences between infected and noninfected infertile men in any of the sperm parameters assessed (sperm concentration, motility and morphology). The results of the three bioassays developed to evaluate sperm physiology, namely spermatozoa-zona pellucida binding, acrosome reaction stimulated with human follicular fluid and zona-free hamster oocyte penetration, showed no differences between infected and noninfected men. Electron microscopy studies suggest that spermatozoa are active agents in the dissemination of the chlamydial infection; they could be acting as 'vehicles' for the pathogens. These, and other results, suggest that the possible effect of C. trachomatis on male fertility is not due to alterations in sperm 'quality' or function, but rather to the transmission of the disease to female partners, causing inflammatory processes and promoting the generation of antisperm antibodies.

Sperm interaction with human oviductal cells in vitro.

In this article we describe the in-vitro interaction between human spermatozoa and oviductal epithelial cell monolayers. Freshly obtained spermatozoa were added to culture dishes containing human oviductal cells (co-culture), culture medium (control) or culture medium which had previously been used for culture of oviductal cells (conditioned medium). At 0, 5, 24, and 48 h of incubation the percentage of motile spermatozoa was determined and their motion characteristics analysed. Aliquots were taken to determine the percentage of acrosome-reacted spermatozoa. The spermatozoa were motile for a longer period in the presence of oviductal cells (54 +/- 9% co-culture versus 18 +/- 3% control, at 48 h) and the kinetics of the acrosome reaction exhibited a different pattern. In the control the percentage of reacted spermatozoa increased progressively throughout incubation. In co-culture, there was an increase only at 5 h; thereafter, the percentage of acrosome reactions did not change. Spermatozoa incubated in conditioned medium exhibited a behaviour halfway between the control and the co-culture. The pattern of sperm movement was not different in any of the experimental conditions. Although there was no binding between spermatozoa and oviductal epithelial cells, the frequency of the ciliary beat increased after spermatozoa were added to the oviductal cell monolayers. These results suggest that incubation with oviductal cells increases sperm survival, stabilizes the acrosome, and modifies the frequency of ciliary beat.

Inhibition of the acrosome reaction by trypsin inhibitors and prevention of penetration of spermatozoa through the human zona pellucida.

In this study we evaluated the effect of several trypsin inhibitors (p-aminobenzamidine: pAB; N-alpha-p-tosyl-L-lysine-chloromethyl-ketone: TLCK and p-nitrophenyl-p'-guanidino-benzoate: NPGM) on sperm binding and penetration of the human zona pellucida. Motile spermatozoa, selected by a two-step Percoll gradient, were incubated at 1 x 10(7) cells ml-1 at 37 degrees C and in 5% CO2 for 4.5 h. This was followed by the addition of 1 mmol pAB l-1 or phosphate-buffered saline (control) for 30 min. Three to four non-viable human oocytes were then added to each sperm suspension and incubated for 3 h. The numbers of spermatozoa bound to the human zona pellucida and in the perivitelline space were determined by phase contrast microscopy. The results showed that pAB significantly inhibited zona penetration by spermatozoa (56 +/- 8% oocytes penetrated, control versus 0 +/- 0% oocytes penetrated, pAB, mean +/- SEM), without modifying spermatozoa-zona pellucida binding. The inhibition of zona penetration was due to a block of the acrosome reaction normally induced by the human zona pellucida. In separate experiments, sperm suspensions pretreated with 1 mmol pAB l-1 or 10 mumol NPGB l-1 exhibited a marked decrease in the percentage of acrosome reactions on the zona surface (85 +/- 4% and 76 +/- 3% inhibition, respectively). In addition, the inhibitors prevented the acrosome reaction induced by human follicular fluid (percentage of acrosome-reacted spermatozoa: control 8 +/- 2; follicular fluid 25 +/- 3; pAB 6 +/- 2; NPGB 8 +/- 1; TLCK 12 +/- 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between sperm concentration and the rate of fertilization in vitro of golden hamster eggs

El éxito de la fecundación depende de una interacción gamética adecuada. La evidencia disponible sugiere que el espermatozoide atravesará la zona pelúcida sólo cuando se asocia con ella en foram oblicua a través de sus bordes dorsal/ventral y anterior. Esta asociación es mediada por receptores espermáticos presentes en el borde externo de la zona pelúcida. La eficiencia de la penetración espermática podría estar asociada con la posibilidad que el espermatozoide pueda establecer ese tipo de asociación. Esta hipótese de trabajo se ensayó con un estudio realizado in vitro en el cual ovocitos de hamster con zona pelúcida se inseminaron con espermatozoides capacitados a concentraciones de 1.000, 24.111 y 48.000 espermatozoides/µl. Los resultados mostraron que al aumentar la concentración espermática, la tasa de fecundación bajó de un 97.7%, con la concentración espermática más baja, a un 63% con la concentración más alta. De la misma manera se observó que el promedio de 2,77 cuando se usó la concentració más alta. En ambos casos las diferencias fueron estadísticamente significativas (P < 0.001). Las observaciones con el microscopio electrónico de barrido mostraron que al usar concentraciones bajas de espermatozoides, éstos se asociaban con la zona pelúcida por sus bordes dorsa/ventral y anterior. Al usar concentraciones altas de espermatozoides, éstos se asociaban a través de su borde anterior. En el primer caso la asociación resultaba en una penetración exitosa, en cambio en el segundo caso, muchos espermatozoides eran incapaces de cruzar la zona

Relationship between sperm concentration and the rate of fertilization in vitro of golden hamster eggs

El éxito de la fecundación depende de una interacción gamética adecuada. La evidencia disponible sugiere que el espermatozoide atravesará la zona pelúcida sólo cuando se asocia con ella en foram oblicua a través de sus bordes dorsal/ventral y anterior. Esta asociación es mediada por receptores espermáticos presentes en el borde externo de la zona pelúcida. La eficiencia de la penetración espermática podría estar asociada con la posibilidad que el espermatozoide pueda establecer ese tipo de asociación. Esta hipótese de trabajo se ensayó con un estudio realizado in vitro en el cual ovocitos de hamster con zona pelúcida se inseminaron con espermatozoides capacitados a concentraciones de 1.000, 24.111 y 48.000 espermatozoides/Al. Los resultados mostraron que al aumentar la concentración espermática, la tasa de fecundación bajó de un 97.7%, con la concentración espermática más baja, a un 63% con la concentración más alta. De la misma manera se observó que el promedio de 2,77 cuando se usó la concentració más alta. En ambos casos las diferencias fueron estadísticamente significativas (P < 0.001). Las observaciones con el microscopio electrónico de barrido mostraron que al usar concentraciones bajas de espermatozoides, éstos se asociaban con la zona pelúcida por sus bordes dorsa/ventral y anterior. Al usar concentraciones altas de espermatozoides, éstos se asociaban a través de su borde anterior. En el primer caso la asociación resultaba en una penetración exitosa, en cambio en el segundo caso, muchos espermatozoides eran incapaces de cruzar la zona (AU)