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Biomedical subjects

M Zanetti

Publications and source records attributed to M Zanetti.

At least 235 records · Page 13Linked to original sources
PubMed1980

Passive Heymann's nephritis as a model of immune glomerulonephritis mediated by antibodies to immunoglobulins.

The autologous phase of passive Heymann's nephritis (PHN) induced in rats by a single injection of rabbit IgG anti-FxlA has been investigated. Tolerance to normal rabbit IgG prior to induction of PHN abolished or strongly diminished the glomerular deposition of the host's IgG during the early autologous phase and prevented the development of proteinuria. Neonatal thymectomy significantly decreased the anti-rabbit IgG response but did not prevent the development and the progression of glomerulopathy. Passive transfer of rat or sheep anti-rabbit IgG hyperimmune serum during the heterologous phase resulted in an earlier accumulation of the injected IgG along the glomerular capillary walls (GCW). These results demonstrate the importance of the host's humoral immune response to the injected rabbit IgG anti-FxlA antibody in the progression and in the maintenance of glomerular immune lesions.

Animals↗
PubMed1979

Enzymatic properties of the Ca2+-binding glycoprotein isolated from preosseous cartilage.

The Ca2+-binding glycoprotein isolated from preosseous cartilage shows also alkaline phosphatase activity. The purification procedure indicates that the enzyme is inhibited in crude extract and conceivably in the intact tissue; the activity may be controlled by the proteoglycans present in the matrix. Other substrates are hydrolyzed by the purified enzyme in addition to p-nitrophenylphosphate; the highest specific activity was measured with ATP and pyrophosphate (PPi) at pH 7.5 and 9.0 Mg2+ induces an activation of ATP and PPi hydrolysis; Ca2+ activates hydrolysis of ATP but inhibits that of PPi. The glycoprotein shows also transphosphorylase activity, L-serine being the best phosphate acceptor. The release or transfer of Pi catalyzed by the glycoprotein can be an important step in calcium phosphate precipitation.

Alkaline Phosphatase↗
PubMed1978

Antibody-coated bacteria in the urinary sediment of rats with experimental pyelonephritis.

The appearance of antibody-coated bacteria in urinary sediment has been evaluated in rats with experimental pyelonephritis. At day 7 after induction of pyelonephritis, 9 out of 11 rats demonstrated antibody-coated bacteria in the urinary sediment. The other 2 rats never had a positive urinary sediment. Following removal of the pyelonephritic kidneys, antibody-coated bacteria disappeared in 7 of 9 previously positive rats. In the 2 rats which continued to show antibody-coated bacteria, the infecting organisms were found in the remaining kidney. The 2 rats which never developed antibody-coated bacteria in urinary sediment had a higher then normal serum antibody titer, and 1 rat with antibody-coated bacteria showed a normal serum antibody titer. It is concluded that although the search for antibody-coated bacteria in urinary sediment is a very useful technique, its negativity does not exclude upper urinary tract involvement; in the case of renal parenchymal infection, immunity is not the same at the systemic and the local site.

Animals↗
PubMedDate not supplied

Triangular fibrocartilage and intercarpal ligaments of the wrist: does MR arthrography improve standard MRI?

The objective of this study was to assess the value of adding MR arthrography to standard MRI for patients with chronic wrist disorders. Thirty consecutive patients (age range, 19-73 years; mean, 36.2 years) were included in the investigation. The images were evaluated blindly and separately by two radiologists with regard to lesions of the scapholunate (SL) and lunotriquetral (LT) ligaments and the triangular fibrocartilage (TFC). Conventional two- or three-compartment arthrography was used as the standard of reference. For TFC lesions, standard MR images had a sensitivity of 92.3% (reader 1) and 84.6% (reader 2) and a specificity of 41.2% (reader 1) and 52.9% (reader 2). For MR arthrography, sensitivity was 84.6% (reader 1) and 84.6% (reader 2) and specificity was 88.2% (reader 1) and 100% (reader 2). For SL ligament tears, standard MRI had a sensitivity of 33.3% (reader 1) and 11.1% (reader 2) and a specificity of 47.6% (reader 1) and 57.1% (reader 2). For MR arthrography, sensitivity was 66.7% (reader 1) and 55.6% (reader 2) and specificity was 52.4% (reader 1) and 81.0% (reader 2). For LT ligament tears, standard MRI had a sensitivity of 28.6% (reader 1) and 35.7% (reader 2) and a specificity of 93.8% (reader 1) and 81.3% (reader 2). For MR arthrography, sensitivity was 35.7% (reader 1) and 23.1% (reader 2) and specificity was 93.8% (reader 1) and 94.1% (reader 2). In conclusion, the diagnostic performance of MRI in suspected lesions of the TFC and the SL and LT ligaments is improved by adding MR arthrography to the standard examination.

Adult↗
PubMedDate not supplied

MRI of the foot and ankle: diagnostic performance and patient acceptance of a dedicated low field MR scanner.

The objective of this study was to compare image quality and patient acceptance of a dedicated .2-T MR system and a 1.0-T whole body system. Forty-one consecutive patients referred for MRI of the foot or ankle were prospectively examined with a dedicated .2-T low field system and a 1.0-T whole body system. Images were evaluated qualitatively by two observers and quantitatively using signal-difference-to-noise ratios. The patients were interviewed with respect to positioning, examination time, noise, claustrophobia, confidence in the diagnosis, and willingness to repeat the examination, using a questionnaire. The qualitative score was significantly higher for the 1.0-T system (2.6 vs 2.2 for reader 1 [P = .008] and 2.6 vs 1.7 for reader 2 [P < .0001]), respectively). The signal-difference-to-noise ratios were also superior for the 1.0-T MR system (2.96 vs .88, P < .0001). However, 96% of the lesions visualized at 1.0 T were also detected with the low field system. Patient acceptance was significantly better for the 1.0-T MR scanner (48.6 vs 43.9, P = .007). Image quality of the dedicated low field system was inferior to the 1.0-T system using objective parameters, and patients did not prefer the low field system. Although only 4% of lesions were missed in this series, the low field MR system can only be recommended when funding is limited and the available space is limited.

Adult↗