Registro de emisiones otoacústicas transientes basado en microcontroladores de alto rendimiento / Transient Otoacoustic Emissions Register based on High Performance Microcontrollers

La hipoacusia tiene una incidencia notable entre los recién nacidos. Una intervención temprana durante el período de maduración auditiva permite minimizar los efectos en el desarrollo intelectual del infante. Se propone el desarrollo de un Registrador de Emisiones Otoacústicas Transientes como parte de un sistema de cribado neonatal basado en microcontroladores de alto rendimiento. La prueba consiste en aplicar periódicamente un estímulo tipo chasquido para obtener la respuesta coclear. Se promedian las señales adquiridas y se aplica la Transformada Rápida de Fourier. El espectro obtenido es dividido en bandas de media octava para analizar la correlación y la relación señal-ruido. Si estos parámetros son mayores que los umbrales de referencia en la mayoría de las bandas, se considera al paciente apto para el desarrollo normal. El firmware fue implementado sobre el procesador STM32F405 y evaluado con el simulador Baby Isao; obteniéndose una sensibilidad del 87.5 por ciento y una especificidad del 93.75 por ciento(AU)

Hearing loss is highly incident among newborns. Early intervention during the period of auditory maturation allows adequate levels of intellectual development to be achieved. The development of a Transient Otoacoustic Emissions Recorder is proposed as part of a neonatal screening system based on high-performance microcontrollers. The test consists of periodically applying a click stimulus to obtain the cochlear response. The acquired signals are averaged and the Fast Fourier Transform is applied. The spectrum obtained is divided into half-octave bands to assess the correlation as well as the signal-noise ratio. If these parameters are greater than the reference thresholds in most of the bands, the patient is considered suitable for normal cognitive development. The firmware was implemented on the STM32F405 processor and evaluated with the Baby Isao simulator; obtaining a sensitivity of 87.5 percent and a specificity of 93.75 percent(AU)

Arteritis de Takayasu / Takayasu's arteritis

Presentamos el caso de una paciente de 28 años quien consulta a nuestra clínica por pérdida bilateral y crónica de la visión y episodios de síncope de reciente aparición. No tenía historia de síntomas sistémicos o debidos a disminución del flujo sanguíneo en las extremidades. Durante la hospitalización se encuentra déficit de pulso en las extremidades superiores. La arteriografía muestra estenosis severa de ambas arterias subclavias, carótidas comunes y la arteria vertebral derecha. Se hizo un diagnóstico de arteritis de Takayasu. Se presenta una revisión corta de la patología (Acta Med Colomb 2011; 36: 93-97).

We describe the case of a 28-year-old woman who presented to our clinic with a history of chronic bilateral visual loss and recent episodes of syncope. She did not have a history of systemic symptoms or manifestations of reduced blood flow in her limbs. During her hospital stay, deficient pulses were discovered in both arms. Once hospitalized the physician discloses a pulse deficit in both arms. Angiographic studies showed severe bilateral stenosis of the subclavian and carotid arteries and of the right vertebral artery. The diagnosis of Takayasu's arteritis was confirmed. A brief review of this disease is presented in this paper (Acta Med Colomb 2011; 36: 93-97).

Enterotoxins, colonization factors, serotypes and antimicrobial resistance of enterotoxigenic Escherichia coli (ETEC) strains isolated from hospitalized children with diarrhea in Bolivia

Enterotoxigenic Escherichia coli (ETEC) is recognized as the main cause of bacterial diarrhoea among children in Asia, Africa and Latin America but less investigated in Bolivia. OBJECTIVE: To determine the relation between enterotoxins, CFs and serotypes as well as the antimicrobial resistance patterns in a set of ETEC isolates collected from hospitalized children with acute diarrhea. In the present study we characterized 43 ETEC strains isolated from 2002 to 2006 from hospitalized children (0-5 years) with acute diarrhea in Bolivia. The strains were analyzed for heat-labile (LT) and heat-stable (ST) enterotoxins and colonization factor (CF) profiles, as well as for serogroups and antimicrobial resistance using phenotypic (ELISA, dot blot, slide agglutination and disc diffusion) and genotypic (Multiplex PCR) methods. Among the ETEC isolates tested, 30 were positive for LT, 3 for STh and 10 for LT/STh. Sixty-five percent (28/43) of the strains expressed one or more CF. The most common CFs were CS17 (n = 8) and CFA/I (n = 8). The phenotypical and genotypical results for toxins and CFs were congruent except for CS21 that was amplified in 10 of the strains by multiplex PCR, but CS21 pili was only detected phenotypically in four of these strains. The ETEC strains had diverse O and H antigens and the most common types were O8:H9 LT CS17 (n = 6; 14 percent) and O78:HNM LT-ST CFA/I (n = 4; 9 percent). The analysis of antibiotic resistance showed that 67 percent (n = 29/43) of the strains were resistant to one or several of the antimicrobial agents tested. Presence of CFs was associated with antibiotic resistance. CONCLUSION: The most common toxin profile was LT 70 percent, LT/STh 23 percent and STh 7 percent. High antimicrobial resistance to ampicillin among serogroups O6, O8 and O78 were the most common.

Estudo dos fatores de virulência das E. Coli isoladas de pacientes com bacteriemia / Study of virulence factors in E. Coli isolated from bacteriemia patients

A prevalência dos fatores de virulência fímbria tipo 1 (tipo 1+), fímbria P (FP+), fímbria F 165 (F165+), a hemolisina (Hly+), antígeno K 1 (K1+) e a resistência à ação bactericida do soro (ABS+), foi pesquisado em 90 cepas de E. coli, isoladas de pacientes com bacteriemia. Quarenta pacientes não apresentaram doença de base (SDB) e os 50 restantes foram subdivididos em recém-nascidos (10), com patologias do trato urinário (15), com doença hematológica (19) e 6 com SIDA (Síndrome da Imundeficiência Adquirida). Nenhum dos fatores associou-se com o quadro clínico, em nenhum dos grupos de pacientes. Foi detectado um fenótipo FP+ Hly+ e houve dependência entre a expressão desta fímbria e a produção da hemolisina. Cinquenta por cento (50) das cepas expressaram duas fímbrias: FP+ tipo 1, FP+ F165+ ou tipo 1+ F165+. O sorogrupo O6 foi o mais prevalente e os sorotipos uropatogênicos O1, O2, O4, O6, O7, O18, e O75, foram detectados em 43,2 por cento

Characterization of necrotizing Escherichia coli strains isolated from diarrheic children in Brazil

Durante estudos epidemiológicos de casos de diarréia em crianças de duas regiöes do Brasil, 17 cepas de E.coli foram isoladas cujos sobrenadantes induziram alteraçöes morfológicas em células Vero semelhantes aquelas induzidas pelo fator citotóxico e necrotizante (CNF). Uma vez que tem sido descrito que CNF näo é detectado no sobrenadante de culturas este estudo foi desenvolvido para melhor caracterizar estas cepas. Todas as amostras foram analisadas quanto à presença de CNF nos sobrenadantes e nos extratos sonicados; atividade necrotizante; produçäo de hemolisina; hemaglutinaçäo manose-resistente; hidrofobicidade superficial; e sorogrupo. Os resultados mostraram que todas as cepas säo capazes de causar necrose em pele de coelho e induzir alteraçöes típicas de CNF1, as quais foram observadas tanto nos extratos sonicados quanto nos sobrenadantes das culturas. Produçäo de hemolisina e hidrofobicidade superficial foi encontrada em respectivamente 76 por cento e 54 por cento das cepas analisadas. Os resultados das hemaglutinaçöes com 6 espécies de eritrócitos mostrou que todas as cepas pertenciam aos tipos III ou IVa de MRHA. A análise dos sorogrupos mostrou que a maioria das cepas (14/17) pertenciam ao sorogrupo O6, duas cepas eram O14 e uma pertencia ao sorogrupo O4. Em conclusäo, demostrou-se que cepas de NTEC podem ser isoladas de fezes de crianças com diarréia no Brasil. Estas cepas produzem CNF1 que podem ser detectado tanto nos sobrenadantes como nos extratos celulares e possuem características muito semelhantes às cepas NTEC isoladas na Europa

A simple and economic slide micro-immunoenzymatic (Micro-SIA) test for epidemiological studies of toxoplasmosis

A slide micro-immunoenzymatic assay (micro-SIA) to detectantibodies to non-particulate Toxoplasma gondii antigens is described. This assay allows the diagnosis of toxoplasmosis infection in about 1 hr. Twenty-four determinations can be performed per slide. Five hundred ng of antigen and 5 or 10 µl drop of each reactive are necessary per well. The clear contrast of colours obtained for negative and positive sera after the test is finished, allows direct discrimination of the results. However, it is possible to quantify the results of the reaction using a minireader. Sera dilution cutoff value, determined as themost frequent titre for the general population, is 1:100. The toxoplasma micro-SIA correlates well with indirect immunofluorescence (IIF), its sensitivity is atleast three times as much as IIF. The test has an intra and inter assay variation coefficient of 5.46 per cent and of 6.24 per cent respectively. Sera obtained at random from argentinian people were analyzed and a 56 per cent of infection was found. The main features of the Toxoplasma micro-SIA are its simplicity, sensitivity, reproducibility, and the virtual absence of background making it very suitable for screening tests

Toxoplasma gondii: a rapid method for the isolation of pure tachyzoites: preliminary characterization of its genome

A rapid and simple technique for the purification of Toxoplasma gondii tachyzoites was developed. Highly purified parasites were obtained from the peritoneal exudates of infected mice by means of two consecutive discontinous sucrose gradients run at low speed (10,000xg, 30 min). Parasites obtained by this method conserved its biological activity. Hybridizations tudies with DNA from healthy mice and from purified tachyzoites preparations demonstrated that Toxoplasma gondii tachyzoites DNA could be obtained with better than 90 per cents purity. Preliminary studies with DNA endonucleases showed the presence in the tachyzoites genome of highly repetitives sequences

Producción experimental de un tipo de ascitis irreversible / Experimental production of an irreversible type of ascitis

Mediante la constricción parcial de la vena cava inferior intratorácica, se indujo un tipo de ascitis en el perro. Se obtuvo en un corto lapso una ascitis persistente, con edema distal, con baja mortalidad postoperatoria y sin repercusión evidente sobre la funcionalidad renal, pero con grave efecto sobre el estado nutricional