First serological and molecular detection of Toxoplasma gondii in guinea pigs (Cavia porcellus) used for human consumption in Nariño, Colombia, South America.

Consumption of undercooked meat is one of the main transmission routes for Toxoplasma gondii worldwide. In the South American Andes, the guinea pig (Cavia porcellus) is a domestic rodent representing one of the main sources of animal proteins for indigenous communities. Although T. gondii infects a wide range of rodents worldwide, the natural impact of the infection on guinea pig populations is still unknown. Our study conducted in guinea pigs that were bred in traditional systems located in the village of José María Hernández (Nariño, Colombia) revealed the presence of T. gondii antibodies in 33.3% (23 out of 69) guinea pigs evaluated, with a cut-off point of 25 for the modified direct agglutination test. Conventional PCR detection of the T. gondii-specific RE fragment (529 bp) in 207 collected tissues demonstrated the presence of T. gondii DNA in several organs, including the brain (16/69), muscle (12/69), and heart (4/69), with an overall molecular detection frequency of 27.5% (19 out of 69 guinea pigs). This is the first report of natural infection of guinea pigs with T. gondii, demonstrating their potential epidemiological role in transmitting the infection to autochthonous populations.

Mechanistic and biological characterisation of novel N5-substituted paullones targeting the biosynthesis of trypanothione in Leishmania.

Trypanothione synthetase (TryS) produces N1,N8-bis(glutathionyl)spermidine (or trypanothione) at the expense of ATP. Trypanothione is a metabolite unique and essential for survival and drug-resistance of trypanosomatid parasites. In this study, we report the mechanistic and biological characterisation of optimised N5-substituted paullone analogues with anti-TryS activity. Several of the new derivatives retained submicromolar IC50 against leishmanial TryS. The binding mode to TryS of the most potent paullones has been revealed by means of kinetic, biophysical and molecular modelling approaches. A subset of analogues showed an improved potency (EC50 0.5-10 µM) and selectivity (20-35) against the clinically relevant stage of Leishmania braziliensis (mucocutaneous leishmaniasis) and L. infantum (visceral leishmaniasis). For a selected derivative, the mode of action involved intracellular depletion of trypanothione. Our findings shed light on the molecular interaction of TryS with rationally designed inhibitors and disclose a new set of compounds with on-target activity against different Leishmania species.

Myofibrillar protein synthesis and muscle hypertrophy individualized responses to systematically changing resistance training variables in trained young men.

The manipulation of resistance training (RT) variables is used among athletes, recreational exercisers, and compromised populations (e.g., elderly) attempting to potentiate muscle hypertrophy. However, it is unknown whether an individual's inherent predisposition dictates the RT-induced muscle hypertrophic response. Resistance-trained young [26 (3) y] men (n = 20) performed 8 wk unilateral RT (2 times/wk), with 1 leg randomly assigned to a standard progressive RT [control (CON)] and the contralateral leg to a variable RT (VAR; modulating exercise load, volume, contraction type, and interset rest interval). The VAR leg completed all 4 RT variations every 2 wk. Bilateral vastus lateralis cross-sectional area (CSA) was measured, pre- and post-RT and acute integrated myofibrillar protein synthesis (MyoPS) rates were assessed at rest and over 48 h following the final RT session. Muscle CSA increase was similar between CON and VAR (P > 0.05), despite higher total training volume (TTV) in VAR (P < 0.05). The 0-48-h integrated MyoPS increase postexercise was slightly greater for VAR than CON (P < 0.05). All participants were considered "responders" to RT, although none benefited to a greater extent from a specific protocol. Between-subjects variability (MyoPS, 3.30%; CSA, 37.8%) was 40-fold greater than the intrasubject (between legs) variability (MyoPS, 0.08%; CSA, 0.9%). The higher TTV and greater MyoPS response in VAR did not translate to a greater muscle hypertrophic response. Manipulating common RT variables elicited similar muscle hypertrophy than a standard progressive RT program in trained young men. Intrinsic individual factors are key determinants of the MyoPS and change in muscle CSA compared with extrinsic manipulation of common RT variables.NEW & NOTEWORTHY Systematically manipulating resistance training (RT) variables during RT augments the stimulation of myofibrillar protein synthesis (MyoPS) and training volume but fails to potentiate muscle hypertrophy compared with a standard progressive RT. Any modest further MyoPS increase and higher training volumes do not reflect in a greater hypertrophic response. Between-subject variability was 40-fold greater than the variability promoted by extrinsic manipulation of RT variables, indicating that individual intrinsic factors are stronger determinants of the hypertrophic response.

Trypanothione synthetase confers growth, survival advantage and resistance to anti-protozoal drugs in Trypanosoma cruzi.

BACKGROUND: Chagas cardiomyopathy, caused by Trypanosoma cruzi infection, continues to be a neglected illness, and has a major impact on global health. The parasite undergoes several stages of morphological and biochemical changes during its life cycle, and utilizes an elaborated antioxidant network to overcome the oxidants barrier and establish infection in vector and mammalian hosts. Trypanothione synthetase (TryS) catalyzes the biosynthesis of glutathione-spermidine adduct trypanothione (T(SH)2) that is the principal intracellular thiol-redox metabolite in trypanosomatids. METHODS AND RESULTS: We utilized genetic overexpression (TryShi) and pharmacological inhibition approaches to examine the role of TryS in T. cruzi proliferation, tolerance to oxidative stress and resistance to anti-protozoal drugs. Our data showed the expression and activity of TryS was increased in all morphological stages of TryShi (vs. control) parasites. In comparison to controls, the TryShi epimastigotes (insect stage) recorded shorter doubling time, and both epimastigotes and infective trypomastigotes of TryShi exhibited 36-71% higher resistance to H2O2 (50-1000 µM) and heavy metal (1-500 µM) toxicity. Treatment with TryS inhibitors (5-30 µM) abolished the proliferation and survival advantages against H2O2 pressure in a dose-dependent manner in both TryShi and control parasites. Further, epimastigote and trypomastigote forms of TryShi (vs. control) T. cruzi tolerated higher doses of benznidazole and nifurtimox, the drugs currently administered for acute Chagas disease treatment. CONCLUSIONS: TryS is essential for proliferation and survival of T. cruzi under normal and oxidant stress conditions, and provides an advantage to the parasite to develop resistance against currently used anti-trypanosomal drugs. TryS indispensability has been chemically validated with inhibitors that may be useful for drug combination therapy against Chagas disease.

Role of Rats ( Rattus norvegicus) in the Epidemiology of Toxoplasma gondii Infection in Grenada, West Indies.

Rodents are known to be reservoir hosts of Toxoplasma gondii infection for other animals, such as cats and pigs. From February to July 2017, 167 rats ( Rattus norvegicus) were trapped in Grenada, and serum, heart, skeletal muscle, and brain were examined for T. gondii infection by serological examination (modified agglutination test, 1:25) for T. gondii antibodies and for viable parasites by bioassay in mice. Samples of heart, skeletal muscle, and brain of all rats were bioassayed in Swiss Webster (SW) outbred albino mice and interferon gamma gene knockout (KO) mice. Toxoplasma gondii was isolated from heart and brain from 1 rat; this was the only seropositive rat. The T. gondii strain was avirulent for SW mice but killed KO mice. Tissue cysts were detected in the brains of SW mice, and tachyzoites were detected in the lungs of KO mice that died of acute toxoplasmosis. The strain was propagated in cell culture, and DNA derived from cell-cultured tachyzoites was genotyped using the 10 PCR restriction fragment length polymorphisms (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). The strain was a clonal Type III (ToxoDB genotype no. 2) strain. Although the prevalence of T. gondii in humans and animals in Grenada is high, rats seem to have little importance in the transmission of T. gondii on this island.

Experimental Neospora caninum infection in chickens (Gallus gallus domesticus) with oocysts and tachyzoites of two recent isolates reveals resistance to infection.

The importance of birds in the biological cycle of Neospora caninum is not clear. We report unsuccessful Neospora infection in chickens (Gallus gallus domesticus) using two isolates of N. caninum. In experiment #1, 30 White Leghorn chickens were orally inoculated with viable N. caninum oocysts (NC-SP1 isolate, 200 oocysts per bird) via the crop at 21days of age. Groups of three birds were euthanised at intervals of 7days (a total of 9weeks) and one group was challenged with the same oocyst dose at 37daysp.i. and observed for 11weeks. Blood samples were collected weekly, and sera were tested using IFAT. Chicken tissues were collected for PCR, quantitative PCR and immunohistochemistry. Two dogs approximately 45days of age were fed with tissues from chickens euthanised at 138 and 159daysp.i. The results indicated that the chickens were resistant to neosporosis as revealed by failure to seroconvert, to detect parasite DNA or N. caninum antigen by immunohistochemistry in inoculated bird tissues, and by no oocyst excretion by the dogs fed avian tissues. Similar results were obtained in experiment #2, in which 34 1-week-old chickens were each s.c. inoculated with 100,000 tachyzoites of the NcWTDMn1 isolate of N. caninum. The chickens were euthanised on days 7, 15, 22, 28, 36 and 60p.i. At necropsy, all tissues and serum from each bird were collected. All chickens remained asymptomatic, and N. caninum antigen was not detected by immunohistochemistry. Seven chickens euthanised at day 60p.i. demonstrated low (1:25 dilution) levels of antibodies by using the Neospora agglutination test. Two 12-week-old dogs fed tissues pooled from 10 inoculated chickens euthanised at day 60p.i. did not excrete N. caninum oocysts. This investigation indicates that chickens are resistant to experimental infection by N. caninum.

Isolation and RFLP Genotyping of Toxoplasma gondii in Free-Range Chickens (Gallus domesticus) in Grenada, West Indies, Revealed Widespread and Dominance of Clonal Type III Parasites.

The objectives of the present cross-sectional study were to isolate and genotype Toxoplasma gondii in free-range chickens from Grenada, West Indies. Using the modified agglutination test, antibodies to T. gondii were found in 39 (26.9%) of 145 free-range chickens with titers of 25 in 7 chickens, 50 in 6 chickens, 100 in 2 chickens, and 200 or higher in 24 chickens. The hearts of the 39 seropositive chickens were bioassayed in mice; viable T. gondii was isolated from 20 and further propagated in cell culture. Genotyping of T. gondii DNA extracted from cell-cultured tachyzoites using the 10 PCR-restriction fragment length polymorphism (RFLP) markers SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed 4 genotypes, including ToxoDB PCR-RFLP no. 2 (Type III), no. 7, no. 13, and no. 259 (new). These results indicated that T. gondii population genetics in free-range chickens seems to be moderately diverse with ToxoDB no. 2 (Type III) as the most frequent (15/20 = 75%) compared to other genotypes in Grenada.

Effectiveness of egg yolk immunoglobulin against the intracellular salmonid pathogen Piscirickettsia salmonis.

AIMS: To produce and characterize egg yolk immunoglobulin (IgY) against the fish intracellular pathogen Piscirickettsia salmonis as well as to evaluate the antibacterial activity of IgY in vitro and the availability in the serum of fish immunized orally. METHODS AND RESULTS: Specific IgY was produced by immunizing hens with P. salmonis proteins. The IgY was obtained from egg yolks using the ammonium sulphate precipitation method and it was characterized by SDS-PAGE, Western-blot and ELISA, demonstrating that anti-P. salmonis IgY strongly reacted specifically against P. salmonis proteins. In an in vitro neutralization assay, IgY inhibited the growth of P. salmonis in liquid medium at concentrations ranging from 128 to 256 µg ml(-1) in a dose-dependent manner. Interestingly, IgY against P. salmonis also generates a strong protective effect on the infection of P. salmonis in salmon head kidney-1 cells. In addition, the bacteriostatic function of IgY appears to result possibly from agglutination by the interaction of IgY with surface components of the pathogen. Finally, to confirm this IgY as an alternative for salmonid treatment, Atlantic salmon (Salmo salar) specimens were orally inoculated with IgY. The analysis of the sera demonstrates that IgY was effectively transported by fish intestine and that this immunoglobulins maintains its properties and recognizes several proteins of P. salmonis up to 12 h after inoculation of IgY against P. salmonis. CONCLUSIONS: Specific IgY effectively inhibited the growth of P. salmonis and this immunoglobulin can be released in the Atlantic salmon sera when administered orally to fish. SIGNIFICANCE AND IMPACT OF THE STUDY: We propose that this specific IgY against this fastidious micro-organism could be a useful strategy for the treatment of piscirickettsiosis.

Isolation and RFLP genotyping of Toxoplasma gondii from the mongoose (Herpestes auropunctatus) in Grenada, West Indies.

Little is known of the genetic diversity and epidemiology of Toxoplasma gondii infection in wildlife in Caribbean Islands. The prevalence and genetic diversity of T. gondii in mongooses (Herpestes auropunctatus) was investigated. During 2011 and 2012, 91 mongooses were trapped in different parts of Grenada, bled, euthanized, and examined at necropsy. Antibodies to T. gondii were found in 27 mongooses tested by the modified agglutination test (cut-off titer 25). Muscles (heart, tongue, neck) of 25 of the seropositive mongooses were bioassayed for T. gondii infection in mice. Viable T. gondii was isolated by bioassay in mice from four mongooses with MAT titers of 1:50 in two, 1:200 for one, and 1:400 for one mongoose. The four T. gondii isolates were further propagated in cell culture. Strain typing of T. gondii DNA extracted from cell-cultured tachyzoites using the 10 PCR-restriction fragment length polymorphism (RFLP) markers SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed one isolate belongs to the Type III (ToxoDB #2) lineage, two to ToxoDB#7 lineage, and one to the ToxoDB #216 lineage. This is the first report of T. gondii isolation and genotyping in H. auropunctatus worldwide.

Schwannoma cervical de la cadena del simpático / Cervical schwannoma of the sympathetic chain

Los schwannomas de la cadena cervical del simpático (SC) son tumores benignos e infrecuentes, que se presentan como una masa cervical unilateral de lento crecimiento, y cuyo diagnóstico preoperatorio definitivo suele ser difícil. A pesar de las pruebas disponibles (TAC, RM, eco y angiografía), solo se obtiene en el momento de la cirugía. El tratamiento de elección es la cirugía, y rara vez se produce recidiva o malignización, aunque sí puede variar hastapresentarse el síndrome de Horner…

Schwannomas of the sympatic cervical chain are infrequent and benign tumors, presented as unilateral cervical mass of slow growth, and whose definitive preoperative diagnosis usually is difficult, in spite of the available tests (CAT, MR, ecography and angiography), obtaining it at the moment of the surgery. Surgical extirpation constitutes the election treatment, being rare the tumor recidive and the malignization, not so the Horner syndrome…

[Placental villous lesions in HIV-1 infection treated with zidovudine]. / Lesiones de la vellosidad placentaria en pacientes con infección por VIH-1 tratadas con zidovudina.

BACKGROUND: HIV-1 reaches the placenta through the maternal-fetal transmission from an infected uterus. This virus has cytolytic capabilities. The placenta in its maturation process has regressive or degenerative changes within certain limits, are considered normal. However, factors such as virus and antiretrovirals, can increase the proportion of these lesions. OBJECTIVE: To evaluate morphological changes in placental villi of pregnant women infected with HIV-1 treated with AZT. MATERIAL AND METHODS: descriptive, prospective, comparative, with non-probability sampling of observations in villi as units of analysis of the placentas from the group of patients with HIV-1 infection and zidovudine regimen and of the control group of four placentas from HIV negative patients. Both groups in the last trimester of pregnancy. H-E staining was used in 25 films from five placental regions of the study group and four from the control group, using a protocol of 6 variables identifying syncytial knots, fibrinoid changes, villous edema, stromal fibrosis, calcification and villous immaturity. Observations were analyzed using ANOVA as a 2 x 5 factorial arrangement with 4 replications subsampling and split plot design and Tukey test. RESULTS: Chorionic villi showed percentages of alterations that exceed the normal range. It showed significant differences (p<0.05) between the placentas exposed to HIV-1 and AZT and normal placentas in relation to the percentage of villi affected by 5 variables, except fibrosis. CONCLUSIONS: The lesions may be increasing the vertical transmission of HIV-1. We also found evidence that the placenta is not in the best conditions for the transfer of gases, nutrients and metabolites, which could promote a decrease in birth weight and placental weight.

Evidence for eosinophil recruitment, leukotriene B4 production and mast cell hyperplasia following Toxocara canis infection in rats.

It is well known that eosinophilia is a key pathogenetic component of toxocariasis. The objective of the present study was to determine if there is an association between peritoneal and blood eosinophil influx, mast cell hyperplasia and leukotriene B(4) (LTB(4)) production after Toxocara canis infection. Oral inoculation of 56-day-old Wistar rats (N = 5-7 per group) with 1000 embryonated eggs containing third-stage (L3) T. canis larvae led to a robust accumulation of total leukocytes in blood beginning on day 3 and peaking on day 18, mainly characterized by eosinophils and accompanied by higher serum LTB(4) levels. At that time, we also noted increased eosinophil numbers in the peritoneal cavity. In addition, we observed increased peritoneal mast cell number in the peritoneal cavity, which correlated with the time course of eosinophilia during toxocariasis. We also demonstrated that mast cell hyperplasia in the intestines and lungs began soon after the T. canis larvae migrated to these compartments, reaching maximal levels on day 24, which correlated with the complete elimination of the parasite. Therefore, mast cells appear to be involved in peritoneal and blood eosinophil infiltration through an LTB(4)-dependent mechanism following T. canis infection in rats. Our data also demonstrate a tight association between larval migratory stages and intestinal and pulmonary mast cell hyperplasia in the toxocariasis model.

Evidence for eosinophil recruitment, leukotriene B4 production and mast cell hyperplasia following Toxocara canis infection in rats

It is well known that eosinophilia is a key pathogenetic component of toxocariasis. The objective of the present study was to determine if there is an association between peritoneal and blood eosinophil influx, mast cell hyperplasia and leukotriene B4 (LTB4) production after Toxocara canis infection. Oral inoculation of 56-day-old Wistar rats (N = 5-7 per group) with 1000 embryonated eggs containing third-stage (L3) T. canis larvae led to a robust accumulation of total leukocytes in blood beginning on day 3 and peaking on day 18, mainly characterized by eosinophils and accompanied by higher serum LTB4 levels. At that time, we also noted increased eosinophil numbers in the peritoneal cavity. In addition, we observed increased peritoneal mast cell number in the peritoneal cavity, which correlated with the time course of eosinophilia during toxocariasis. We also demonstrated that mast cell hyperplasia in the intestines and lungs began soon after the T. canis larvae migrated to these compartments, reaching maximal levels on day 24, which correlated with the complete elimination of the parasite. Therefore, mast cells appear to be involved in peritoneal and blood eosinophil infiltration through an LTB4-dependent mechanism following T. canis infection in rats. Our data also demonstrate a tight association between larval migratory stages and intestinal and pulmonary mast cell hyperplasia in the toxocariasis model.

Evaluación de percepción de conocimientos y destrezas de alumnos de medicina en traumatología y ortopedia / Evaluation of students perception of knowledge and skills in orthopedics

Objectives: To evaluate student’s opinion about the knowledge and skills acquired during their graduate training. To evaluate the level of completion of the minimal required objectives assessed by the Medical National Exam (EUNACOM). Materials and Methods: Prospective research. descriptive and transversal. 152 final year medical students, from 3 different Universities (U1, U2 and U3), answered an anonymous and voluntary questionnaire. Inclusion criteria: Final year medical students who had completed their orthopedics rotation. The questionnaire evaluated 4 areas of knowledge and skills. General clinical conditions; emergency consultations; laboratory and radiologic exam interpretations; and clinical procedures. On each areas, the student, could consider themselves well prepared or unprepared. University programs were analyzed and evaluated, according to the completion of the objectives indicated by EUNACOM. Results: Percentage of students who considered themselves well prepared versus unprepared (WP vs UP): general clinical conditions: WP = 63.15 percent vs UP = 36.85 percent; emergency consultations: WP = 61.05 percent vs UP = 38.95 percent; interpretations of laboratory and radiologic exams: WP = 63.66 percent vs UP = 36.34percent; clinical procedures: WP = 21.50 percent vs UP = 78.05 percent. Regarding the University programs, a maximum potential score of 185 points was possible, U1 obtained 68 points; U2, 74 points and U3, 131 points. Conclusion: A high percentage of students feel they don’t have the knowledge and skills required in Orthopedics. Programs accomplish only partially the orthopaedic objectives assessed by EUNACOM.

Objetivos: Evaluar la opinión de los alumnos sobre los conocimientos y destrezas adquiridas en ortopedia y traumatología durante su formación de pregrado. Evaluar si los programas universitarios de pregrado cumplen con los perfiles del Examen Único Nacional de Conocimientos en Medicina (EUNACOM). Material y Métodos: Estudio prospectivo, descriptivo transversal. Se encuestaron en forma anónima y voluntaria a 152 internos de séptimo año de medicina de tres universidades de la Región Metropolitana (U1, U2 y U3). Criterios de inclusión: Internos de medicina de séptimo año con rotaciones completas en ortopedia y traumatología. La encuesta evalúa cuatro áreas de conocimientos y destrezas: patologías clínicas generales, patología de urgencia, interpretaciones de exámenes de laboratorio e imagenología y realización de procedimientos. En cada área el alumno puede considerarse bien preparado o mal preparado. Se realizó un análisis y revisión comparativa de los programas universitarios, asignándoles un puntaje de acuerdo a los perfiles descritos por el EUNACOM. Resultados: Porcentaje de alumnos que se consideraron bien preparados versus mal preparados (BP vs MP): patologías clínicas generales: BP 63,15 por ciento vs MP 36,85 por ciento; patología de urgencia: BP 61,05 por ciento vs MP 38,95 por ciento; interpretación de exámenes de laboratorio e imagenología: BP 63,66 por ciento vs MP 36,34 por ciento; realización de procedimientos: BP 21,50 por ciento vs MP 78,05 por ciento. Respecto a los programas universitarios de un total posible de 186puntos, U1 obtuvo 68, U2 74 y U3 131. Conclusiones: Un alto porcentaje de los alumnos de pregrado no se siente bien preparado en Ortopedia y Traumatología. Los programas sólo cumplen parcialmente con los perfiles EUNACOM.

Presencia de alteraciones histopatológicas en vellosidades placentarias normales en Maracay (Venezuela) / The presence of hystopathological alterations in normal placental villi in Maracay, Venezuela

Objetivo: determinar la proporción de las alteraciones histopatológicas en las vellosidades y en el espacio intervelloso obtenida de cuatro placentas normales del último trimestre del embarazo. Metodología: por medio de la microscopía de luz y la tinción de hematoxilina y eosina (H&E) se identificaron, en 25 láminas de 5 regiones de la placenta, 6 variables cuantitativas (p.ej. inmadurez vellosa, nódulos sincitiales, cambios fibrinoides, edema velloso, fibrosis estromal y calcificación) y 9 variables cualitativas (p.ej. depósitos de fibrina, trombosis intervellosa, infartos, trombosis vascular, cambios en la pared del vaso, calcificación intraluminal, congestión vascular,inflamaciónyhemorragia).Los resultados de las variables cuantitativas se analizaron utilizando el Análisis de Varianza (ANAVAR) de 2 vías con submuestreo y el test de Tukey. En contraste, para las variables cualitativas se aplicó la prueba de Kruskal Wallis y se estimó el porcentaje de positividad según las regiones. Dichos análisis se realizaron por medio del software Statistix® 8.0 y SAS® 9.0 para Windows®. Resultados: no se presentaron diferencias significativas (p<0,05) entre las placentas más no entre las regiones. Del mismo modo, no se observó trombosis vascular, daño de la pared de lvaso,congestión vascular, calcificación intraluminal, inflamación ni hemorragia. Conclusión: las vellosidades analizadas se mostraron homogéneas dentro de cada placenta pero no entre las mismas, indicando una variabilidad que etiológicamente podría explicarse por factores genéticosyambientalesdecuyainteracciónresultarían las diferencias individuales para cada placenta.

Objective: determining the percentage of histopathological changes in chorionic villi and intervillous space in four placentas obtained from normal women’s pregnancies at term. Methodology: six quantitative variables (i.e. immaturity, syncytial knots, fibrinoid change, oedema, fibrosis and calcification) and nine qualitative variables (i.e. fibrin deposition, intervillous fibrin, infarction, thrombosis, changes in vessel walls, intraluminal calcification, vascular congestion, inflammation and haemorrhage) were indentified on 25 slides covering 5 placental regions using light microscopy and H&E staining. Quantitative variable results were analysed using two-way variance analysis with sub-sampling and Tukey’s test; qualitative variables (the percentage of positive regions) were analysed by Kruskal-Wallis test. The software used was Statistix® 8.0 and SAS® 9.0 for Windows®. Results: there were significant differences (p<0.05) between placenta (but not between regions) regarding syncytial knots, fibrinoid change, oedema, fibrosis and calcification. Vascular thrombosis, damage to vessel walls, vascular congestion, intraluminal calcification, inflammation and/or haemorrhage were not observed. Conclusion: the population of villi analysed was homogeneous in each placenta but not amongst them, thereby indicating variability which could be etiologically explained by genetic and environmental factors whose interaction may have resulted in the individual differences observed for each placenta.

A crucial role for TNF-alpha in mediating neutrophil influx induced by endogenously generated or exogenous chemokines, KC/CXCL1 and LIX/CXCL5.

BACKGROUND AND PURPOSE: Chemokines orchestrate neutrophil recruitment to inflammatory foci. In the present study, we evaluated the participation of three chemokines, KC/CXCL1, MIP-2/CXCL2 and LIX/CXCL5, which are ligands for chemokine receptor 2 (CXCR2), in mediating neutrophil recruitment in immune inflammation induced by antigen in immunized mice. EXPERIMENTAL APPROACH: Neutrophil recruitment was assessed in immunized mice challenged with methylated bovine serum albumin, KC/CXCL1, LIX/CXCL5 or tumour necrosis factor (TNF)-alpha. Cytokine and chemokine levels were determined in peritoneal exudates and in supernatants of macrophages and mast cells by elisa. CXCR2 and intercellular adhesion molecule 1 (ICAM-1) expression was determined using immunohistochemistry and confocal microscopy. KEY RESULTS: Antigen challenge induced dose- and time-dependent neutrophil recruitment and production of KC/CXCL1, LIX/CXCL5 and TNF-alpha, but not MIP-2/CXCL2, in peritoneal exudates. Neutrophil recruitment was inhibited by treatment with reparixin (CXCR1/2 antagonist), anti-KC/CXCL1, anti-LIX/CXCL5 or anti-TNF-alpha antibodies and in tumour necrosis factor receptor 1-deficient mice. Intraperitoneal injection of KC/CXCL1 and LIX/CXCL5 induced dose- and time-dependent neutrophil recruitment and TNF-alpha production, which were inhibited by reparixin or anti-TNF-alpha treatment. Macrophages and mast cells expressed CXCR2 receptors. Increased macrophage numbers enhanced, while cromolyn sodium (mast cell stabilizer) diminished, LIX/CXCL5-induced neutrophil recruitment. Macrophages and mast cells from immunized mice produced TNF-alpha upon LIX/CXCL5 stimulation. Methylated bovine serum albumin induced expression of ICAM-1 on mesenteric vascular endothelium, which was inhibited by anti-TNF-alpha or anti-LIX/CXCL5. CONCLUSION AND IMPLICATIONS: Following antigen challenge, CXCR2 ligands are produced and act on macrophages and mast cells triggering the production of TNF-alpha, which synergistically contribute to neutrophil recruitment through induction of the expression of ICAM-1.

Cambios degenerativos coriónicos asociados a malformaciones fetales del tubo neural durante el tercer trimestre del embarazo / Chorionic degenerative changes associated to fetal neural tube malformations during the third trimester of pregnancy

Evaluar las características de las vellosidades placentarias, sus vasos y espacio intervelloso. Estudio descriptivo, observacional, cualitativo-cuantitativo, retrospectivo, con muestreo no probabilístico de 6 placentas asociadas con malformación del tubo neural, analizadas mediante miscrocopia de luz comparadas en igual número de placentas no asociadas a malformación del tubo neural que sirvieron como controles. Los resultados se analizaron con la prueba de tendencia para datos correlacionados de respuesta dicotómica. Laboratorio de Microscopia Electrónica, CIADANA, Facultad de Ciencias de la Salud, Maracay. Se observaron nódulos sincitiales, cambios fibrinoides, necrosis trofoblástica, edema, fibrosis estromal, trombosis, inflamación de la pared del vaso, un número de vasos de 4 a 6 por sección de vellosidad, calcificación intraluminal, daño de la pared del vaso, trombosis intervellosa y presencia mínima de células inflamatorias en las vellosidades observadas. Hubo diferencias significativas con respecto a edema y necrosis trofoblástica entre ambos grupos. En el grupo de estudio una mayor proporción de edema y necrosis trofoblástica provocarían la eliminación de vellosidades cuyas placentas están con deficienca placentaria indicando que aquellos cambios o agentes causales de la malformación fetal también estarían provocando anomalías en el desarrollo placentario.

Cambios ultraestructurales del trofoblasto en los casos de hipoxia durante la preeclampsia / Ultraestructural changes of trophoblast in hipoxic cases during

Examinar la ultraestructura del sincitiotrofoblasto en placentas de embarazadas complicadas con preeclampsia con especial referencia al efecto de la hipoxia sobre la estructura fina del tejido. Diez placentas, a término, afectadas por preeclampsia, fueron tomadas inmediatamente después del parto por cesárea y de cada una de ellas tres biopsias de la superficie maternal se disecaron en sala de parto, en especímenes de 2 a 5 mm, y se fijaron por inmersión en glutaraldehido al 4 por ciento, pH 7,4,a 4 ºC. Posteriormente se dividieron en fragmentos de 1 mm y sumergidos en solución fresca fijadora por períodos variables de 2 a 72 horas seguidas por una fijación secundaria en tetraóxido de osmio al 1 por ciento en buffer fosfato 0,1 M durante 1 hora. Las muestras se procesaron siguiendo los procedimientos convencionales de a microscopia electrónica de transmisión para su observación. Laboratorio de microscopia electrónica del Ciadana, Facultad de Ciencias de la Salud, Maracay. Los hallazgos revelan proyecciones de la membrana plasmática del sincitio de diversas formas, que simulan desprenderse de la superficie. La membrana basal del sincitio se mostró engrosada. Mitocondrias en diversos grados de degeneración presentaron partículas electron densas en la matriz mitocondrial. Regiones apicales del citoplasma sincitial parecen desprenderse hacia el espacio intervelloso. Numerosas vacuolas intracitoplasmáticas y ampliaciones de las cisternas del retículo endoplásmico rugoso se destacan en el citoplasma. Interrupciones de la membrana sincitial y regiones citoplásmicas sin membrana plasmática se notaron. Fragmentos del sincitio desprendidos de la superficie del mismo sugieren ser los corpúsculos que dañan los endotelios de la unidad materna – feto – placentaria constituyendo uno de los estímulos para l mantenimiento de a patogénesis de a preeclampsia.

Presence of oxytocin receptors in the gonadotrophin-releasing hormone (GnRH) neurones in female rats: a possible direct action of oxytocin on GnRH neurones.

Gonadotrophin-releasing hormone (GnRH) neurones constitute the final output pathway of a neuronal network that controls the preovulatory luteinising hormone (LH) surge and ovulation. Throughout the reproductive cycle, several neurotransmitters stimulate and inhibit the activity of GnRH neurones, including oxytocin. The central administration of oxytocin antiserum abolishes the pro-oestrous LH surge whereas oxytocin stimulates GnRH secretion from hypothalamic explants suggesting an oxytocin central action. Within the GnRH neuronal population in the rat, GnRH cells in the medial preoptic area (MPOA) are activated at the time of the LH surge. Thus, we hypothesised that GnRH neurones in the MPOA may express oxytocin receptors, and that oxytocin neurones in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) may be differentially activated during the oestrous cycle. Oxytocin receptors mRNA was detected in the MPOA using reverse transcription-polymerase chain reaction. In animals in either metoestrus or pro-oestrus, double-label immunofluorescence indicated that approximately 10% of GnRH neurones in the MPOA coexpressed oxytocin receptors and that a few oxytocin fibres are located in the vicinity of these GnRH neurones. However, other neurones positive for the oxytocin receptors were found near GnRH neurones. At both oestrous stages, double-label immunofluorescence revealed that approximately 30% of oxytocin neurones in the SON were Fos-positive whereas oxytocin neurones in the PVN were consistently Fos-negative. Together, these data suggest that oxytocin may directly control neuronal activity in a subpopulation of GnRH neurones. Moreover, both oxytocin neuronal activity and the oxytocin receptor expression on GnRH cells are not influenced by oestrogen.