RESUMEN
BACKGROUND: Quite often subjects affected by chronic hepatitis C virus infection have no clinical signs of liver disease and serum aminotransferase values never go beyond the upper limit of normal. Yet these subjects, defined "asymptomatic HCV carriers", often have active viral replication and various degrees of histological damage. AIMS: To verify, in a population of antibody to hepatitis C virus carriers, if normal serum aminotransferase values in hepatitis C virus-RNA positive differed considerably from those in hepatitis C virus-RNA negative subjects. SUBJECTS/METHODS: We followed 24 anti-hepatitis C virus-positive subjects (15 hepatitis C virus-RNA positive and 9 negative) by measuring alanine and aspartate aminotransferase levels at 3-month intervals for a median of 40 months (range 6-77). RESULTS: Determinations resulted repeatedly and rigorously within the normal range in all participants. Alanine aminotransferase values were higher in hepatitis C virus-RNA positives than in negatives (mean +/- SD: 0.609+/-0.172 vs 0.434+/-0.153 times the upper limit of normal; pAsunto(s)
Hepatitis C Crónica/sangre
, Transaminasas/sangre
, Carga Viral
, Adulto
, Anciano
, Alanina Transaminasa/sangre
, Aspartato Aminotransferasas/sangre
, Portador Sano/sangre
, Portador Sano/diagnóstico
, Femenino
, Hepacivirus/aislamiento & purificación
, Anticuerpos contra la Hepatitis C/sangre
, Hepatitis C Crónica/diagnóstico
, Humanos
, Masculino
, Persona de Mediana Edad
, ARN Viral/sangre
RESUMEN
The maximum number of nucleoli was counted in interphase nuclei of Posidonia oceanica, and a restriction pattern of nuclear rDNA was obtained after digestion with four restriction endonucleases and Southern hybridization. P. oceanica has only one type of ribosomal gene whose size was estimated to be 18.5 kbp long. The nucleotide sequence of the entire ITS region was also determined by direct sequencing of PCR amplified DNA fragments. The sequence of the ITS region was aligned with those of homologous regions of other monocots available in literature, and phylogenetic trees were obtained.
Asunto(s)
Nucléolo Celular/genética , ADN de Plantas/genética , ADN Ribosómico/genética , Filogenia , Plantas/genética , Secuencia de Bases , ADN de Plantas/química , ADN Ribosómico/química , Evolución Molecular , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , ARN de Planta/genética , ARN Ribosómico/genética , ARN Ribosómico 5.8S/genética , Mapeo Restrictivo , Alineación de Secuencia , Homología de Secuencia de Ácido NucleicoRESUMEN
The aim of this study was to evaluate the blood lead levels in a sample of Bologna's population, 12 years after the previous screening campaign carried out in 1984. The investigated sample was divided, as in 1984, by age, sex, occupational exposure and selected life style factors. The blood lead levels presented a sharp reduction in comparison with the values observed in the previous study. In 1996, the 50 degrees, 90 degrees and 98 degrees percentile of blood lead were 50 micrograms/l, 90 micrograms/l and 140 micrograms/l whereas in 1984 they were 129 micrograms/l, 242 micrograms/l and 329 micrograms/l, respectively. Possibly, this result is related to a lower level of environmental lead pollution as a result of the increasing use of unleaded gasoline in new cars.
Asunto(s)
Exposición a Riesgos Ambientales , Plomo/sangre , Adolescente , Adulto , Anciano , Consumo de Bebidas Alcohólicas/epidemiología , Niño , Preescolar , Monitoreo del Ambiente , Monitoreo Epidemiológico , Femenino , Gasolina , Humanos , Italia/epidemiología , Plomo/efectos adversos , Intoxicación por Plomo/epidemiología , Estilo de Vida , Masculino , Tamizaje Masivo , Persona de Mediana Edad , Morbilidad/tendencias , Programas Nacionales de Salud , Prevalencia , Factores de Riesgo , Muestreo , Fumar/epidemiología , Población Urbana , Emisiones de Vehículos , VinoRESUMEN
The study of the fine-scale structure of biological tissues is crucial for diagnosing a wide number of different diseases. In X-ray images, fine structures usually induce a correlation among image gray levels and are commonly perceived as textures. In this paper, we report on a Computer Vision approach to the characterization of biological tissues as imaged by standard X-ray techniques. In particular, using features derived from co-occurrence matrices, we have assessed spatial gray-level dependence of bone tissue and lung parenchyma images. A hybrid neural network was adopted to distinguish pathological tissues from normal ones and to classify different pathologies.
Asunto(s)
Intensificación de Imagen Radiográfica/métodos , Enfermedades Óseas/diagnóstico por imagen , Huesos/diagnóstico por imagen , Diagnóstico Diferencial , Humanos , Articulación de la Rodilla/diagnóstico por imagen , Pulmón/diagnóstico por imagen , Enfermedades Pulmonares/diagnóstico por imagen , Redes Neurales de la Computación , Distribución Normal , Probabilidad , Sensibilidad y EspecificidadRESUMEN
Image reference databases (IRDBs) are a recurrent research topic in medical imaging. Most IRDBs are designed to help experienced physicians in diagnostic tasks and require that users have prior extensive knowledge of the field for their use to be fruitful. Therefore, the educational potential of such image collections cannot be exploited thoroughly. In this paper we propose an image-indexing method to extend the functionalities of an existing medical IRDB and allow for its use in educational applications, as well as in computer-assisted diagnosis. Our method, based on the Kahrunen-Leève transform, has been used to develop a content-based search engine for tomographic image databases on which we are presently experimenting and which we aim to integrate into a working radiological IRDB installed at the University of Florence. Results achieved in our preliminary tests are also reported.
Asunto(s)
Procesamiento de Imagen Asistido por Computador , Almacenamiento y Recuperación de la Información , Integración de Sistemas , Encéfalo/anatomía & histología , Gráficos por Computador , Humanos , Imagen por Resonancia Magnética , Multimedia , Diseño de Software , Telemedicina , Interfaz Usuario-ComputadorRESUMEN
The real utility of high resolution computed tomography (HRCT) for early detection of lung involvement was investigated in eighteen patients affected with systemic sclerosis (SSc). The results obtained from HRCT have been compared with traditional (chest radiographs, pulmonary function tests (PFT)) and nontraditional (ventilation and perfusion scintiscan) modalities of lung investigation. A significant statistical correlation (p < 0.001) between HRCT scans and chest radiographs was observed. Moreover, HRCT was more sensitive in the detection of early pulmonary interstitial involvement and more accurate in the assessment of interstitial fibrosis in cases with severe lung involvement. A statistical correlation (P < 0.001) between HRCT and the modalities of investigation of alveolo-capillary membrane--as PFT and ventilation scintiscan--was also observed. These results indicate that in SSc HRCT may be a useful technique for assessing early pulmonary involvement and for complementing other methodologies of investigation of lung function.
Asunto(s)
Pulmón/diagnóstico por imagen , Esclerodermia Sistémica/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adulto , Aerosoles , Anciano , Femenino , Humanos , Microesferas , Persona de Mediana Edad , Perfusión , Radiografía Torácica , Cintigrafía , Respiración , Pruebas de Función Respiratoria , Esclerodermia Sistémica/diagnóstico , Pentetato de Tecnecio Tc 99mRESUMEN
Spin echo multiecho sequences are not frequently used in clinical practice, because they allow the observation of one single slice, imaged at different echo times, for each acquisition. To limit examination time, multislice sequences that include only images derived from one or two echoes are usually acquired. Nevertheless, the strong T2 dependence of multiecho sequences can be used effectively to enhance the contrast between tissues with different T2 and to gather useful diagnostic information. Artificial neural networks can offer new interesting facilities to the radiologist. In fact, the learning capabilities of neural networks allow them to extract the prototypical behavior of a system from a set of examples. After learning, artificial neural networks can emulate the system behavior even in the presence of new inputs, as far as these are not too different from those included in the training set. A conveniently trained neural network can synthesize a multiecho sequence for each slice of a multislice sequence, requiring only two images for each slice to achieve reliable results. When compared with a true multiecho sequence, the images generated by the network preserve the contrast characteristics of the original ones and have a better signal-to-noise (SNR) ratio. In this paper we report the results achieved by using a neural network to reconstruct synthetic spin echo multiecho images of the brain.
Asunto(s)
Imagen por Resonancia Magnética , Redes Neurales de la Computación , Procesamiento de Imagen Asistido por ComputadorRESUMEN
The authors describe an original technique to calculate the coordinates for CT-guided stereotactic biopsies of brain lesions. On the basis of simple trigonometric formulas it is possible to get an accuracy of +/- 1 mm. By means of the standard software of a high precision CT and with a CT-compatible stereotactic apparatus the x, y, and z coordinates are obtained in a quick and reliable way. A further development of the trigonometric approach to the stereotactic calculations is the "double target technique". It allows to preset the path of the biopsy-device through a selected point, to reach the final target: in this way a valuable reduction of the surgical risk is afforded especially in critical areas of the brain (brain stem, pineal region etc.).
Asunto(s)
Neoplasias Encefálicas/patología , Encéfalo/patología , Técnicas Estereotáxicas , Tomografía Computarizada por Rayos X , Biopsia , Tronco Encefálico/patología , Gráficos por Computador , Humanos , Riesgo , Técnicas Estereotáxicas/instrumentaciónRESUMEN
Magnetic resonance imaging is a new completely non-invasive diagnostic technique now available even for heart studies. Due to the long time of this examination the main goal for the application to the cardiovascular diagnosis is to obtain the major number of information in a reasonable time for the patient. On the basis of our initial experience with this technique we propose a method suitable for the morphological, functional and tissular characterization in cardiovascular diagnosis.
Asunto(s)
Cardiopatías/diagnóstico , Espectroscopía de Resonancia Magnética , Aorta/anatomía & histología , Atrios Cardíacos/fisiopatología , Ventrículos Cardíacos/fisiopatología , Humanos , Contracción MiocárdicaRESUMEN
Magnetic resonance evaluation of 28 cases of pituitary adenomas has shown remarkable accuracy. Compared with HR-CT, MR gives comparable results in tumour identification. MR better demonstrates the suprasellar extension of macroadenomas and their relationship to the visual pathway and is more effective in showing direct and indirect signs of microadenomas. HR-CT however better recognized bone abnormalities of the sella turcica, due to adenomas. A typical increased signal intensity has been demonstrated in most of the adenomas studied.