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Biomedical subjects

R De Dominicis

Publications and source records attributed to R De Dominicis.

At least 19 recordsLinked to original sources
PubMed2000

Subjects positive for hepatitis C virus RNA with normal aminotransferase levels, a "trompe l'oeil" clinical picture?

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; p<O.001). Aspartate aminotransferase values in both groups reflected the same consistent difference (mean +/- SD: 0.652+/-0.170 vs 0.528+/-0.151 times the upper limit of normal, p<0.001). CONCLUSIONS: Our findings demonstrate that biochemical activity exists in asymptomatic hepatitis C virus-RNA-positive carriers, but it is so slight that serum aminotransferase levels do not go beyond the upper limit of normal. With the prevailing range of normality, serum aminotransferase determination is a helpful but not reliable marker of disease activity in chronic hepatitis C virus infection. The normal range for aminotransferases needs to be redefined in order to set up a more accurate diagnostic profile of subjects with chronic hepatitis C virus infection.

Adult↗
PubMed1998

[Trends in blood lead levels in the population of the city of Bologna].

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.

Adolescent↗
PubMed1997

Tissue characterization from X-ray images.

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.

Bone Diseases↗
PubMed1992

High resolution computed tomography in systemic sclerosis. Real diagnostic utilities in the assessment of pulmonary involvement and comparison with other modalities of lung investigation.

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.

Adult↗
PubMed1992

Neural network synthesis of spin echo multiecho sequences.

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.

Image Processing, Computer-Assisted↗
PubMed1986

[Methods for studying the heart with magnetic resonance].

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.

Aorta↗
PubMed1985

[Magnetic resonance and computerized tomography in the study of hypophyseal adenomas. Comparative results].

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.

Adenoma↗