Search PubMed⌕ Search

Biomedical subjects

M Visconti

Publications and source records attributed to M Visconti.

14 recordsLinked to original sources
PubMed1979

[Multielectronic computerized EMG: technical notes on the recording and parallel off-line elaboration].

A Multielectrodic EMG analysis program is developing. The purpose is to get as short as possible the main EMG parameters (amplitude, duration, frequency) of most motor units, and to reach an estimation of the anatomical extent of single units. According to the muscle extent a variable number of electrodes are inserted crosswise the fibers. EMG signals are simultaneously recorded on a multichannel AMPEX FR1300 and then off-line processed by a 21MX HP minicomputer connected with a 5Mbytes disc drive. Some technical problems had to be solved:channel amplification adjustment to avoid any difference among preamplifiers calibration and filtering, severe hum filtering of main power that is specially strong in nultielectrodic recording systems, the need of sampling at the same Nyquist time the signals of different channels. The computer is instructed to identify the "sinchronous" units i.e. the motor units recorded from more than one channel. These motor units are detected, counted and deleted from all the channels, except the one where they show the maximum amplitude. The percentage of these sinchronous units depends upon the interelectrodic distance and their anatomical area, thus it can support an evaluation of motor unit anatomical spread.

Computers↗
PubMed1978

Quantitative determination of propildazine in rat plasma by gas-liquid chromatography.

A gas-liquid chromatographic method for the evaluation of the new anti-hypertensive drug propildazine (ISF 2123) in rat plasma is described. The procedure involves separation of the drug from plasma by cation-exchange chromatography, subsequent acylation of the dried eluate with heptafluorobutyric anhydride and quantitation with electron-capture detection. Propildazine can be determined in concentrations down to ca. 0.4 microgram/ml.

Animals↗
PubMed1975

[Frequency of antigen associated to hepatitis due to virus B (HBAg) and of antibody (HBAc) in healthy subjects and during of course of acute and chronic hepatitis. Radioimmunologic study].

Among the several methods employed for the detection of hepatitis B antigen (HBAg) and hepatitis B antibody (HBAb), radioimmunoassay is considered to be the most sensitive and specific. This paper describes a radioimmunoprecipitation test (RIP) for HBAg and HBAb standardized in our laboratory; it consists of a double-antibody precipitation test in a micro-titer system employing 125I-labeled HBAg. The test is compared with double immunodiffusion (ID) and with counterimmunoelectrophoresis (CEP) in the detection of HBAg and HBAb in healthy persons and in patients with acute and chronic liver disease. RIP is 20,000 times more sensitive than ID and 2,500 times than CEP when HBAg is tested, and 40,000 times more sensitive than ID and 10,000 times than CEP for the antibody detection. Moreover the method is reproducible and specific for HBAg and HBAb. With this test the frequency of HBAg in healthy persons was 0% in subjects without any known contact with antigenic material, 0.80% in hospital personnel and 1.17% in high risk personnel (laboratory technicians, blood products workers, ecc.). In acute viral hepatitis the frequency of HBAg was 90% at the admittance to the hospital and 70% at the dimission, while CEP detected a frequency of 85% and 20% respectively. In chronic liver disease the frequency of HBAg with the RIP method was 83.3% in chronic persistent hepatitis, 42.8% in chronic aggressive hepatitis, 23% in cryptogenic cirrhosis and 16.6% in alcoholic cirrhosis. The frequency of HBAb detected with RIP was 4.50% in subjects without any known contact with antigenic material, 6.45% in hospital personnel, 0.41% in high risk personnel, 20% in acute viral hepatitis at the admittance to the hospital and 50% at the discharge, 25% in chronic persistent hepatitis, 14.2% in chronic aggressive hepatitis, 15.3% in cryptogenic cirrhosis and 50% in alcoholic cirrhosis. The high frequency of antibody in healthy persons with no history of hepatitis or parenteral exposure to blood transfusion suggests a widespread diffusion of hepatitis B infection and the possibility of a nonparenteral route transmission. The frequency of HBAg and HBAb in chronic liver disease as detected by a very sensitive method rises the question of a possible role of hepatitis B virus in the pathogenesis of the disease.

Acute Disease↗