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Biomedical subjects

A Benassi

Publications and source records attributed to A Benassi.

At least 55 records · Page 3Linked to original sources
PubMed1983

Different degrees of atherosclerosis detected by backscattered ultrasound: an in vitro study on fixed human aortic walls.

The aim of the study was to establish whether ultrasonic backscattered signals may characterize the atherosclerotic process, providing a quantitative assessment of severity. Measurements on aortic specimens were made in vitro by a transducer acting as transmitter and receiver. Two different indices were measured, one based on peak amplitude value (Vmax) and the other on fast Fourier transform (FFT) analysis of ultrasonic reflected signal (IBI). Two hundred fixed aortic wall specimens (50 normal, 50 fatty streaks, 50 fibrofatty, and 50 calcific) were first characterized ultrasonically and then pathologically, both macroscopically (before ultrasonic study) and histologically (after it). Differentiation of normal, fibrofatty and calcific specimens was achieved using Vmax. Values obtained in fatty streaks overlapped with normal wall but significantly differed from values of fibrofatty and calcific subsets. The results with IBI were similar except that the difference between normal and fibrofatty specimens was not statistically significant. Such changes in acoustic behavior of atherosclerotic walls could be due to increased deposition of highly echogenic biological materials, such as collagen, cholesterol crystals (in fibrofatty specimens), and calcium salts (in calcific ones). Therefore, backscattered signals appear to provide in vitro simple parameters indicative of changes in the arterial wall structure due to the atherosclerotic process.

Aorta↗
PubMed1983

[Technical variations in abdominal heterotransplants of the heart].

The Authors describe the innovations by them introduced in a series of 15 experiments of abdominal heart heterotopic transplantation done in the Institute of Veterinary Physiology and Biochemistry University of Milano. Particularly they recommend the use of cardioplegia and the prolene as suture's material to reduce the ischemic time. Also they signal the importance of a new position of the transplanted heart with the apex looking at the head of the recipient. They think this position should be the best to preserve the anatomical connections between the great vessels of the guest heart.

Animals↗
PubMed1980

a new fiber-optic liquid crystal catheter for oxygen saturation and blood flow measurements in the coronary sinus.

A new catheter for oxygen saturation and thermodilution measurements in the coronary sinus is described. The distinctive feature of this catheter is a new cholesteric liquid crystal (CLC) temperature sensor. Described in brief are the constructive and performance characteristics of the sensor, which permits temperature measurement by means of luminous pulses transmitted through optical fibres. The advantages of this solution are pointed out in terms of patient safety and instrumental integration of the thermodilution and oxygen saturation measurements both achieved through reflection photometry via optical fibres. Two possible configurations of the new catheter, with a double or a single optical connector, are illustrated and the instruments designed to be used with each catheter, are also described. Preliminary animal experiments on the application of the new catheter for the study of the coronary circulation are finally reported.

Animals↗
PubMed1980

[Low reliability of ECG monitoring in CCU for detection of ischemic episodes (author's transl)].

In 10 patients with frequent anginal attacks admitted to CCU, 2-lead ECG Holter monitoring (H-M) was performed for a total of 10 days. The number of ischemic episodes detected by retrospective analysis of H-M was compared with the number detected on the basis of symptoms and continuous visual ECG monitoring in CCU (CCU-M) by highly trained staff. A total of 157 episodes was identified by H-M [82 ST elevation (ST), 15 ST depression (ST) and 60 t wave changes]. Only 15 of these episodes were detected by CCU-M (13 ST, 1 ST and 1 T wave changes) of which 12 were symptomatic. When 6 H-M ECGs were simultaneously displayed on an oscilloscope in real-time (as in CCU-M), one of the Authors was able to detect only 36% of the episodes, whereas the frequency reached 80% when the analysis was limited to one tape at the time. The results show the low reliability of the CCU-M in detecting ischemic attacks; this appears mainly related to the display of multiple tracings.

Angina Pectoris↗
PubMed1977

[The quantitative cineangiography. Part II. Computerized analysis of the left ventricular volumes in man (author's transl)].

The values of left ventricular volumes (EDV and ESV) were determined in 35 patients with various heart diseases by computerized reading technique utilizying both the area-length and the slice methods. The data thus obtained were compared both with those derived manually and with those obtained following injection of 113mIn into the left ventricle and monitoring by external counting the dilution curve. Good agreement among the data obtained by the various methods was found. It appears, then, in the clinical practice, the computerized method has definite advantages over the others since it allows quick determination of the data and therefore examination of multiple frames.

Adolescent↗
PubMed1977

[Quantitative cineangiography. Part I. Computerized volumetry of ventricular models (author's transl)].

A computerized system for cineangiograms analysis is described. Each selected frame is displayed by a TV camera on a TV monitor, allowing the physician to draw the left ventricular contour using a light-pen. The coordinates of selected points are sent to a small size digital computer to be processed. The processing techniques are outlined, while particular evidence is given to the operating procedure. Left ventricular volume is evaluated using both area-length and slice methods. Results obtained on models yield an estimation of the accuracy of the volume measurements.

Angiocardiography↗
PubMedDate not supplied

In vivo radiofrequency ultrasound analysis of normal human heart structures.

Twenty young subjects were studied with a microprocessor system for quantitative analysis of backscattered radiofrequency (RF) signals from normal heart structures. This system allows an "on line" quantitative evaluation of the amplitude of the RF "native" signal, before the chain of processing and display, with the acquisition gate displayed on a conventional M-mode machine. Septum, posterior wall, and anterior mitral leaflet were analyzed. The gate length was kept at 3 microseconds (2.35 mm) for the ventricular walls (excluding endo- and epicardial reflections), and at 1 microsecond (0.8 mm) for the mitral valve. Integrated backscatter index (IBI) was calculated as the time integral of [u(t)[, where u(t) = i(t) X s(t); is the time sequence of backscattered echoes and s(t) is the time gate delimiting the thickness of the insonated tissue. The IBI was expressed in percent, normalized for the pericardial interface (the strongest reflection was assumed to be 100%). The percent IBI for the septum was found to be 22 +/- 4%; for the posterior wall it was 17 +/- 3%; for the anterior mitral leaflet it was 5 +/- 2%. A second reading of the same structures was performed by the previous observer and by a new one. Good intraobserver (r = 0.92) and interobserver (r = 0.88) correlations were obtained. In conclusion, a regional variation in echo amplitude from different heart structures can be observed in man. This set of values can be used as normal values for future studies in pathologic conditions.

Adult↗
PubMedDate not supplied

[Validation of PM10 and PM2.5 personal samplers: comparison between PEM and CEN-ARPAV selectors].

In order to validate specific personal selectors for the collection of fine particles, 65 double measurements of PM10 and PM2.5 were carried out at the same collection site; thus allowing a comparison between two different methods of sampling. The first method was that normally used by ARPAV in order to sample the above-mentioned granulometric fractions in outdoor environment. The second method was chosen by us for personal sampling (PEM working at 2 l/min and at 4 l/min). In both cases the filters gravimetric analysis conformed to the expectations of D.M. 60 of 2/4/2002. The comparison between the two methods showed a good correlation in both the granulometric fractions: correlation coefficients r for the PM2.5 are equal to 0.96 and 0.99 for the PEM working at 2 l/min and at 4 l/min respectively; r for the PM10 are equal to 0.98 and 0.99 for the PEM working at 2 l/min and at 4 l/min respectively. The analysis of results in terms of fine particles concentration and difference between methods against their mean, shows a slight overestimate of the particles concentration with PEM working at 2 l/min, compared to those working at 4 l/min. Nevertheless, considering the good results obtained even with a flow of 2 l/min, we believe that using PEM working at 2 l/min to monitoring 24 hours-personal exposure assures an improved capacity in the battery-operated pumps.

Air Pollutants↗