Biomedical subjects
Publications and source records attributed to M Rossi.
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The authors have evaluated 22 patients with renal pelvis tumour (RPT) by means of excretory urography and ultrasonography. Six patients also underwent arteriography. The value of the three investigations in the diagnosis of the lesion, the nature, the pyelic origin and the extension are presented. It is concluded that urography remains the method of choice for the evaluation of RPT while ultrasonography may be considered complementary to urography in cases of non-functioning kidney, when the urographic filling device defect is uncertain and in the differentiation between the pyelic or parenchymal origin of the tumour.
Hypotheses about the interactions of effectors with conformations of allosteric enzymes having co-operative kinetics can be tested simply and exactly without knowledge of the nature of the intersubunit co-operativity by using a linkage approach to the analysis of steady-state kinetics. Applying this approach to competition for substrate sites in the allosteric enzyme donkey spleen dCMP aminohydrolase, we show that the kinetics are consistent with the hypothesis that the substrate dCMP and the competitor dAMP, as well as the allosteric activator dCTP, bind exclusively to the same conformation of the enzyme subunits. The linkage test can be applied in the presence of other effectors without knowledge of how these interact with the enzyme. Our tests showed that dCMP and DAMP are still bound exclusively to this same conformation in the presence of the product dUMP or of the allosteric inhibitor dTTP. We give evidence that dUMP binds to the same conformation as dCMP, but that it is also bound to other conformation(s). The advantages of the linkage approach, and some general problems in steady-state kinetics of allosteric enzymes, are discussed.
Is well-known the haemolitic action that A-vitamine exerts on the erythrocytes. With our study we have submitted the erythrocytes, of forty normal subjects, to incubation to 37 degrees C and to constant traumatic action with and without A-vitamine. After we have dosed the haemoglobin and potassium in the plasma to various times of incubation and traumatic action. The results demonstrate that this vitamine determines an increase of the fragility of the erythrocytes beyond the 100% after 120 minutes, while protects the membrane of erythrocytes to the release of potassium.
In order to define the sensitivity and specificity of ultrasonography (US) in the diagnosis of hydronephrosis, 125 patients with normal renal function were examined after urography using high-resolution real-time scanning. The overall diagnostic accuracy of US in detecting hydronephrosis was 85.2%, with a specificity of 84.4% and a sensitivity of 89.9%. It is concluded that US may be considered the screening test of choice for the diagnosis of hydronephrosis. However, urography is still required for the evaluation of renal function, site, and nature of the obstruction when US shows a dilated collecting system and in the patient with a normal US but renal colic.
The crystal and molecular structure of metyrapone, a powerful inhibitor of certain cytochromes P-450, is described. Cytochrome P-450 enzymes are involved in metabolic processes, including those activating insecticides, drugs, and carcinogens. Metyrapone inhibits both the adrenal cytochrome P-450 catalyzing 11-beta-hydroxylation in steroid biosynthesis and most microsomal cytochromes P-450 induced by phenobarbital pretreatment. Crystal data are as follows: a = 11.828 (1), b = 6.268 (6), c = 18.269 (3) A, beta = 115.27 (1) degree, V = 1224.9 (3) A3, space group P21/c, dcalcd = 1.227 g cm-3, Z = 4. No intermolecular interactions are apparent in the solid state other than van der Waals forces. The torsion angle about the C(7)-C(10) bond to which the two 3-pyridyl groups are attached is 59.4 (1) degree. The three negatively charged heteroatoms form a triangle; the nitrogen atoms are anti to the exocyclic oxygen and are 4.347 (1) A apart. The N5-O11 distance is 5.850 (1) A; the N14-O11 intramolecular distance is 4.750 (1) A. The "twisted butterfly" conformation found for metyrapone is found in other molecules that are substrates and inducers of the specific cytochrome P-450 inhibited by metyrapone. The availability of nucleophilic functional groups is a feature common to most directly acting inhibitors of cytochrome P-450 enzymes and is manifested in metyrapone by the presence of the basic nitrogens. These factors may be necessary for interaction with the protein.
M-mode echocardiographic peripheral venous contrast studies of 23 patients with complex forms of univentricular heart were compared with cineangiocardiographic findings obtained in traditional and axial projections. The morphology of the main ventricular chamber (left type 16, right 6, indeterminate 1), of the rudimentary chamber (16 anterior and four posterior), the type and modalities of atrioventricular connections (common AV valve 6, two AV valves 13, absent left connection 4), the connections and the interrelationships of the great arteries as well as the degree of obstruction of the outlet portions were analysed by both methods. M-mode echocardiography did not provide valuable information about atrioventricular valve morphology: in three cases discordant results were found. Contrast studies improved the diagnostic capabilities and allowed identification of double inlet connection in 10 out of 11 patients and of single inlet in four out of five patients respectively.
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The authors evaluated the results of 24 percutaneous nephrostomies. Pelvic neoplasms involving ureters were the most frequent indications to the procedure (71% of the cases). In all patients the placement of a catheter was possible. The authors describe the techniques performed and evaluate their advantages and limits. The problems related to the use of nephrostomy in patients with widespread neoplasms and severely ill are discussed. The most frequent drawback was catheter dislodgement (25% of the cases). No serious complications occur. Percutaneous nephrostomy is a temporary or permanent form of urinary diversion in obstructive nephropathies, alternative to surgical nephrostomy.
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The clinical, radiological and pathological findings, natural history and response to treatment are investigated in 3 patients. They represent the only examples of W.G. who were seen over a 15 year period at our University Hospital and are characteristic of generalize and limited form. The role of immune complexes in the pathogenesis of W.G. and diagnostic importance of pulmonary radiological pattern are described.
The results of an epidemiological study using the case-control method on 150 oesophageal cancer cases, observed at the IIIrd Surgical Department in Padua and on 150 controls are presented. The results show that alcohol an maize flour (corn meal) are two aetiopathogenetic factors of verified statistical significance in oesophageal carcinoma in the Veneto population. This confirms other studies among populations with a high risk of oesophageal cancer.