High resolution computed tomography (HRCT) of pulmonary infections in AIDS patients.
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AIDS-Related Opportunistic Infections↗
Biomedical subjects
G Guidi
Publications and source records attributed to G Guidi.
Serum melatonin in multiple myeloma: natural brake or epiphenomenon?
Melatonin (MEL), the main hormone produced by the pineal gland, seems to exert antineoplastic activity both in vitro and in vivo. Moreover, several studies reported increased melatonin blood levels in cancer patients. Plasma melatonin concentrations were determined in 46 patients with multiple myeloma and in 31 age matched healthy subjects (57.8 +/- 6.9 versus 55.2 +/- 8.9 years). Venous blood was drawn between 7.30 and 9.30 a.m. and melatonin was assayed using a commercially available radioimmunoassay. The data were analysed by Student's t test and results reported as mean values +/- standard deviation. The patients with multiple myeloma showed significantly higher mean melatonin serum levels than healthy subjects (21.6 +/- 13.5 versus 12.1 +/- 4.8 pg/ml; p < 0.001). This behaviour could actually represent a phenomenon secondary to an altered endocrine-metabolic balance caused by an increased demand of the developing tumor. On the other hand, the increased melatonin secretion might be considered as a compensatory mechanism due to its antimitotic action and therefore as an effort to secrete substances capable of regulating neoplastic growth.
Adult↗
[High resolution computerized tomography: dose evaluation with an anthropomorphic phantom].
High resolution Computed Tomography (HRCT), a technique for pulmonary parenchyma studies, has been for a long time performed with only few scans with a large interval in between: the reasons were the supposed increase in the dose to the patient after kVp and mAs increase, which is necessary to reduce background noise, and the characteristic distribution of most diffuse lung diseases. Of late, HRCT skin dose has been demonstrated to be markedly lower than that of conventional CT (8/10 mm contiguous slices). To evaluate organ doses to patients during HRCT, we compared conventional CT (10 mm slices), HRCT (1.5 mm slices) and chest X-ray doses, as measured on an anthropomorphous phantom. We tested several scan protocols, with different kVp and mAs values to simulate various clinical situations for the two techniques, always with both slice thickness values and both contiguous and non-contiguous (10 mm gap) slices for HRCT scans. Doses were substantially similar for the two methods with contiguous slices in every protocol. "Clinical" HRCT dose (non-contiguous slices with 10 mm gap) is much lower than that of conventional CT--i.e., about 13% of conventional CT dose. On the other hand, HRCT dose is still two orders of quantity higher than that of standard radiography. To conclude, the importance of HRCT in pulmonary parenchyma studies is confirmed.
Models, Biological↗