Detection of Exudates and Microaneurysms in the Retina by Segmentation in Fundus Images / Detección de Exudados y Microaneurismas en la Retina por Segmentación en Imágenes de Fondo

ABSTRACT This article proposes two methodologies for the detection of lesions in the retina, which may indicate the presence of diabetic retinopathy (DR). Through the use of digital image processing techniques, it is possible to isolate the pixels that correspond to a lesion of RD, to achieve segmenting microaneurysms, the edges of the objects contained in the image are highlighted in order to detect the contours of the objects to select by size those that meet an area of 15 to 25 pixels in the case of 512x512 images and identify the objects as possible microaneurysms, while for the detection of exudates the green channel is selected to contrast the luminous objects in the retinography and from the conversion to gray scale, a histogram is graphed to identify the ideal threshold for the segmentation of the pixels that belong to the exudates at the end of the optical disk previously identified by a specialist. A confusion matrix supervised by an ophthalmologist was created to quantify the results obtained by the two methodologies, obtaining a specificity of 0.94 and a sensitivity of 0.97, values that are outstanding to proceed with the classification stage.

RESUMEN Este artículo propone dos metodologías para la detección de lesiones en la retina, que pueden significar la presencia de retinopatía diabética (RD). Mediante el uso de técnicas de procesamiento de imágenes digitales se logra aislar los pixeles que corresponden a una lesión propia de RD, para lograr segmentar microaneurismas se resaltan los bordes de los objetos contenido en la imagen con la finalidad de detectar los contornos de los objetos para seleccionar por tamaño los que cumplan con un área de 15 a 25 pixeles en el caso de imágenes de 512x512 y se identifiquen los objetos como posibles microaneurismas, mientras que para la detección de exudados se selecciona el canal verde para contrastar los objetos luminosos en la retinografía y a partir de la conversión a escala de grises se grafica un histograma para identificar el umbral idóneo para la segmentación de los pixeles que pertenecen a los exudados al final eliminar el disco óptico previamente identificado por un especialista. Se creó una matriz de confusión supervisada por un oftalmólogo para cuantificar los resultados obtenidos por las dos metodologías obteniendo una especificidad del 0.94 y una sensibilidad del 0.97, unos valores que son sobresalientes para proceder con la etapa de clasificación.

Relation of cerebrospinal fluid/plasma HIV-RNA discordance with neurocognitive impairment.

Neurological involvement is common in patients infected with HIV. The effectiveness of antiretroviral drugs in lowering the levels of HIV-RNA in cerebrospinal fluid (CSF) is limited by their inability to cross the blood–brain barrier. Discordance in CSF/plasma HIV-RNA levels may have a bearing on the progression of neurological disease in these patients. We report a woman with subacute neurocognitive impairment and abnormal findings on brain MRI, in whom there was a discordance between CSF/plasma HIV-RNA levels. The patient improved after a change in her highly active antiretroviral therapy (HAART) regimen. We also reviewed the available literature on the subject and found seven articles describing 27 patients. Natl Med J India 2015;28:228–32

Utilization of molasses and sugar cane bagasse for production of fungal invertase in solid state fermentation using Aspergillus niger GH1

Agro-industrial wastes have been used as substrate-support in solid state fermentation for enzyme production. Molasses and sugarcane bagasse are by-products of sugar industry and can be employed as substrates for invertase production. Invertase is an important enzyme for sweeteners development. In this study, a xerophilic fungus Aspergillus niger GH1 isolated of the Mexican semi-desert, previously reported as an invertase over-producer strain was used. Molasses from Mexico and Cuba were chemically analyzed (total and reducer sugars, nitrogen and phosphorous contents); the last one was selected based on chemical composition. Fermentations were performed using virgin and hydrolyzate bagasse (treatment with concentrated sulfuric acid). Results indicated that, the enzymatic yield (5231 U/L) is higher than those reported by other A. niger strains under solid state fermentation, using hydrolyzate bagasse. The acid hydrolysis promotes availability of fermentable sugars. In addition, maximum invertase activity was detected at 24 h using low substrate concentration, which may reduce production costs. This study presents an alternative method for invertase production using a xerophilic fungus isolated from Mexican semi-desert and inexpensive substrates (molasses and sugarcane bagasse).

Cryptococcoma of the brain in an immunocompetent man.

Cryptococcosis is a common opportunistic systemic disease in immunocompromised patients. Pulmonary or brain cryptococcosis is the most common clinical presentation. Immunocompetent patients can also be affected, especially in tropical and subtropical zones where the life cycle of the causal agent, Cryptococcus gattii, is completed. We present a previously healthy man with progressive intracranial hypertension and a right paraventricular mass on CT scan and MRI. Cryptococcus gattii yeasts were isolated from the cerebrospinal fluid. A ventriculoperitoneal shunt was placed and the patient was treated with amphotericin B, fluconazole and dexamethasone. The patient died due to severe intracranial hypertension.

Gastric emptying rates in idiopathic dyspepsia with and without hunger pain

It has been previously observed that in dyspeptic patients with hunger pain, that is, with pain suggestive of the presence of peptic ulcer, only 12% had an endoscopically demonstrated ulcer, the remaining 88% showing absence of important macroscopically detectable lesions (idiopathic dyspepsia). In order to investigate the possibility of a relationship between hunger pain and some alteration in gastroduodenal motility, the gastric emptying rates of patients presenting idiopathic dyspepsia with and without hunger pain were compared with those of normal control subjects. The study was conducted in 40 patients presenting idiopathic dyspepsia, 20 with and 20 without hunger pain, and 30 voluntary apparently normal control subjects. The patients and the controls ingested, with a standard breakfast, a gelatine capsule containing 10 radioopaque polyurethane markers, and the gastric emptying of the markers was evaluated taking 3 x-ray films of the abdomen at 1.5, 3.0 and 4.5 hours after the breakfast. The gastric emptying rates of the markers were significantly higher in the patients with hunger pain, and significantly lower in the patients without hunger pain, than in the normal control subjects. In idiopathic dyspepsia with and without hunger pain there are, respectively, abnormally increased and abnormally decreased gastric emptying rates of undigestible solid markers. Our findings could help to better understand the pathogenesis of those different types of dyspepsia and, consequently, to improve their treatment.

Doble camara de salida de ventriculo derecho con comunicacion interventricular restrictiva. / Double outlet right ventricle with restricted ventricular communication

Se informan dos casos con doble camara de salida, del ventriculo derecho y comunicacion interventricular subaortica restrictiva. Ambos tenian situs solitus y concordancia atrioventricular. No existian otros defectos asociados. En los dos casos el diagnostico se establecio por cateterismo y angiocardiografia; en el segundo fue comprobado por estudio anatomico. Como dado de ayuda diagnostica se menciona la sobrecarga de las cavidades izquierdas en el electrocardiograma, los datos radiologicos de crecimiento del atrio y ventriculo izquierdos asociados a hipertension venocapilar pulmonar, el gradiente de presion existente entre los dos ventriculos, cuantificado por medio del cateterismo cardiaco,asi como los hallazgos angiocardiograficos.En uno de los casos existia discontinuidad mitroaortica. En el segundo con comprobacion anatomica, se observo doble infundibulo, siendo que el que correspondia al ventriculo izquierdo era el responsable de la comunicacion interventricular restrictiva. Se concluye que las dobles camaras de salida del ventriculo derecho con comunicacion interventricular restrictiva tienen caracteristicas clinicas, hemodinamicas y angiocardiograficas que ameritan un diagnostico preciso en funcion de un tratamiento quirurgico adecuado