Estudio del polimorfismo genético de las células de la médula ósea y del sistema nervioso central de ratas mediante la técnica de RAPD / Study of genetic polymorphism of the bone marrow and the central nervous system of rats cells by RAPD technique

Los modelos experimentales en rata han sido de gran utilidad en las evaluaciones terapéuticas o de reemplazo de células en enfermedades neurodegenerativas. Se ha comprobado que las células de la médula ósea (CMO) de ratas pueden diferenciarse en células que no forman parte de sus linajes normales. Hay evidencias de estos procesos de trans-diferenciación, pero aún no se conocen los mecanismos moleculares que activan estos procesos. El propósito de nuestro trabajo fue estudiar el polimorfismo genético del ADN de los tipos celulares que conforman las CMO y las células del sistema nervioso central (SNC), estríatales y de la corteza de ratas mediante la técnica de RAPD. Las CMO, las células mononucleares (CMMO), las células estromales (CEMO) y las del SNC fueron obtenidas de ratas, y su ADN genómico fue purificado y amplificado mediante la técnica de RAPD, utilizando 15 cebadores al azar. Se construyó un dendograma de las bandas de amplificación generadas utilizando el método de UPGMA. Las células estudiadas según el análisis del RAPD quedaron en 2 grupos bien definidos, pudiéndose diferenciar las CEMO del resto de las células estudiadas. Los cebadores OPA-6, 7 y 12, mostraron el polimorfismo genético de los linajes de células estudiadas. Mediante la técnica de RAPD se demostró la variabilidad genética entre las CEMO y las CMMO, células estriadas y de corteza que mostraron una homogeneidad genética, proponiéndose marcadores específicos de RAPD para cada grupo de células. Este es el primer estudio del polimorfismo genético de las CMO y del SNC de ratas.

Experimental models have been of grate usefulness in the therapeutic or replacement cells in neurodegenerative diseases. It has been demonstrated that bone marrow cells (BMC), can be difefferentiated in cells that do not form part of their normal lineage. There is evidence of these trans-differentiation processes in these cells, but nevertheless, molecular mechanisms that activate these differentiation process still not known. The purpose of our work was to study the genetic polymorphism of those cellular types; that conform the rat bone marrow cells (BMC) as well as those of the central nervous system (CNS), striatum cells and cortex ones, trough RAPD technique. BM, mononuclear cells (BMMC), estromal cells (BMSC) and the CNS cells were obtained from rats and genomic ADN was purified and amplified through RAPD technique, using 15 random primers. A dendogram was constructed according to UPGMA method of the amplifying RAPD bands. Studied cells as- according to the RAPD analysis- were grouped into 2 well- defined groups, as CEMO coud be differentiated from the rest of studied cells. OPA-6, 7 and 12 primers showed the genetic polymorphism of the studied lineages cells. Also will be proposed specific RAPD genetic markers. Through RAPD technique permitted the genetic variability was demonstrated betwen BMEC and BMMC of striated cells and of cortex, which demonstratd a genetic homogeneity through RAPD technique so specific genetic markers of RAPD were thus propose for each group of cells. These constitute the first study on genetic polymorphism of BMC and CNS.

Comparison of 16S rDNA-PCR amplification and culture of cerebrospinal fluid for diagnosis of bacterial meningitis

Early and accurate diagnosis of bacterial meningitis is of critical concern. Optimum and rapid laboratory facilities are not routinely available for detecting the etiologic agents of meningitis. The objective of this study was to compare polymerase chain reaction [PCR] assay with culture for detection of bacteria in central nervous system [CNS] samples from patients suspected to have meningitis. One-hundred CSF samples were obtained and divided into two parts. One part of samples was used for standard bacterial culture and gram staining. The remaining was used for DNA extraction. PCR assay was performed with universal primers for 16S rDNA gene of bacteria. Performance characteristics of the test were determined. The PCR method was able to detect bacteria in all 36 culture-positive and in 38 of 64 culture-negative cases showing sensitivity and specificity of 100% and 40.6% respectively. Positive predictive value was 48.6% and negative predictive value 100%, however, Kappa coefficient showed the correlation of the 2 methods to be at 0.33. There are advantages and disadvantages in performance characteristics of the conventional CSF culture and universal CSF 16S rDNA PCR. Therefore, it is recommended to use both methods in clinical practice, particularly in suspicious contaminated samples, with presumable presence of fastidious or slow growing bacteria because of antibiotic consumption

Compromiso neurológico por Mycoplasma pneumoniae en niños: Experiencia del Hospital Nacional Cayetano Heredia / Neurological disorders by Mycoplasma pneumoniae in Children: The experience of Hospital Nacional Cayetano Heredia

Introducción: Las complicaciones neurológicas por Mycoplasma pneumoniae han sido descritas desde hace más de 50 años. Este microorganismo puede causar entre 5 y 10 por ciento del total de infecciones del sistema nervioso central. En Perú, esta enfermedad es subdiagnosticada debido a la falta de sospecha clínica.Objetivos: Describir las características clínicas y de laboratorio de los pacientes con afección del sistema nervioso central por M. pneumoniae, diagnosticados en el Hospital Nacional Cayetano Heredia. Material y métodos: Se revisó la base de datos de la Unidad de Neurología Pediátrica y el libro de egresos del Departamento de Pediatría del Hospital Nacional Cayetano Heredia. Se incluyó a todos los pacientes con compromiso neurológico por M. pneumoniae. Se recopilaron datos clínicos y epidemiológicos. Resultados: Se identificaron 8 pacientes. Tres presentaron mielitis, cuatro presentaron encefalitis y una niña tuvo encefalitis y mielitis. El diagnóstico se estableció por serología IgM. Los pacientes con encefalitis tuvieron frecuentes secuelas neurológicas. En el grupo de mielitis, excepto una niña con localización cervical, todos evolucionaron favorablemente. Los niños con encefalitis fueron más sintomáticos, llegando al estado de coma con necesidad de soporte ventilatorio y crisis epilépticas de difícil control. Conclusiones: Las infecciones del sistema nervioso central por M. pneumoniae existen en nuestro medio y son poco diagnosticadas. Deben formar parte del enfoque diagnóstico de cualquier paciente con afección aguda y subaguda del sistema nervioso central para detectarla precozmente y evaluar opciones terapéuticas.

Introduction: Neurological complications of Mycoplasma pneumoniae have been described for more than 50 years. This microorganism can cause between 5 and 10 per cent of the infections of Central Nervous System. In Peru, this disease is subdiagnosed due to lack of clinical suspicion. Objectives: To describe the clinic and laboratorial characteristics of patients with M. pneumoniae CNS commitment, diagnosed in the Cayetano Heredia National Hospital. Material and methods: The Database of the Unit of Neuropediatrics and the Register of Discharges from the HNCH were reviewed. We include all the patients with neurological commitment by M. pneumoniae. The clinical and epidemiologic data were compiled.Results: There were 8 patients identified. Three children underwent myelitis, four had encephalitis and one girl presented encephalitis and myelitis. The diagnosis was stablished by positive IgM serology. The patients with encephalitis had high percentage of neurological sequelaes. In the myelitis group, except a girl with cervical location, all evolved favorably. Children with encephalitis were much more symptomatic, arriving at the state of coma with ventilatory support requirement and difficult-to-control seizures. Conclusions: Central nervous system infections due to M. pneumoniae do exist in our own environment but are infrequently diagnosed. They should be suspected upon in any patient with acute or subacute infection of the central nervous system to afford early diagnosis and treatment.

Neuroaspergillosis in an immunocompetent patient.

Aspergillosis of the central nervous system (CNS) is an uncommon infection, mainly occurring in immunocompromised patients. We report a case of neuroaspergillosis caused by Aspergillus flavus in an immunocompetent patient presenting as a space-occupying lesion of the CNS. The patient was responding favorably to voriconazole at the time of this report.

Papel de la Toxina Shiga en el sindrome urémico hemolítico / Role of the Shiga toxin in the hemolytic uremic syndrome

In the last years, infection associated with Shiga toxin-producing Escherichia coli (STEC) and subsequent Hemolitic-Uremic Syndrome (HUS) became relevant as a public health since it was considered as one of the most important emergent patogen present in the food contaminated by cattle feces. STEC infection may be asymptomatic or begins with a watery diarrhea that may or may not progress to bloody diarrhea (hemorrhagic colitis) and HUS. In Argentina, HUS is the most common pediatric cause of acute renal insufficiency and the second cause of chronic renal failure. Up to now, STEC infection lacks of known effective treatment strategies that diminish risk of progression to HUS. The mechanisms by which Shiga toxin (Stx) induce HUS may help to find strategies to prevent or ameliorate HUS. In this article, recent progress that has contributed to understanding the disease pathogenesis of STEC is reviewed. New strategies to prevent further uptake of Shiga from the gut, either during the diarrheal phase or once HUS has developed are discussed.

Neurobrucellosis

Brucellosis, which is endemic in Saudi Arabia, can present as a disease with multisystem involvement. Occasionally the organisms invade the central nervous system producing varied neurological manifestations. Often the clinical diagnosis of neurobrucellosis is not straight forward and is obscure. Certain criteria have to be fulfilled for the definitive diagnosis of neurobrucellosis. We report 2 cases of neurobrucellosis which were encountered for the first time during the past 10 years at this hospital

Candidiasis urinaria y cerebral en un neonato con malformación urinaria bilateral congénita: hallazgos ultrasonográficos / Neonatal brain and urinary candidal infection: US findings

El pronóstico de este trabajo es describir los hallazgos ecográficos y demostrar la utilidad del ultrasonido en el diagnóstico precoz de la candidiasis urinaria y cerebral, por lo que realizamos ecografía prenatal de una paciente en la que se diagnosticó la presencia de un feto con uronefrosis bilateral congénita y ecografías tempranas al neonato pretérmino. La detección por US de la presencia de bolas fúngicas dentro de la vía excretora previamente dilatada fue determinante para realizar el cateterismo de ambos uréteres por medio del cual se obtuvo material para cultivo y sirvió para derivación urinaria. Concluimos que el US es el mejor método de diagnóstico por imágenes para ser utilizado en los neonatos prematuros de bajo peso y de alto riesgo