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Biomedical subjects

A Perissinotto

Publications and source records attributed to A Perissinotto.

11 recordsLinked to original sources
PubMed1992

External callus development on ultrasound and its mechanical correlation.

The authors compare the variations in the ultrasonographic and radiographic images with the strain gage values in long bone fractures treated by external fixation. The three test parameters were applied during the entire healing process of 239 fractures. There is a direct correlation between ultrasonographic changes and the calcification of the periosteal callus; there is also a correlation between the morphologic development visible on ultrasound and the stage of the callus. The strain gage values recorded were consistent with these variations.

Biomechanical Phenomena↗
PubMed1991

Coronary hemodynamics and myocardial metabolism in patients with syndrome X: response to pacing stress.

Coronary hemodynamics, myocardial metabolism and left ventricular function at rest and after incremental atrial pacing were evaluated in 12 patients with stress-induced angina and ST segment depression, angiographically normal coronary arteries and no evidence of spasm, generally labeled as syndrome X, and in 10 normal subjects. At baseline study, great cardiac vein flow was comparable in patients and control subjects. During pacing, an equivalent rate-pressure product was reached in the two groups, but the slope of the relation between rate-pressure product and great cardiac vein flow was significantly less steep in patients than in normal subjects (0.0027 vs. 0.0054 ml/mm Hg.beat, p less than 0.001). Nevertheless, the left ventricular ejection fraction was comparable in both groups at rest (66 +/- 6% vs. 71 +/- 7%, p = NS) and during pacing (71 +/- 7% vs. 66 +/- 5%, p = NS). At baseline study, myocardial glucose extraction was more efficient in patients with syndrome X (p less than 0.05), but net myocardial exchange of pyruvate and alanine was, respectively, smaller and greater than in control subjects. Lactate was extracted to a similar extent in the two groups and in no instance was net lactate release observed during pacing or recovery. During pacing and recovery, patients with syndrome X showed net pyruvate release, unlike the control subjects in whom net pyruvate exchange was positive. In addition, patients with syndrome X continued to show net myocardial extraction of alanine during spacing and recovery, whereas normal subjects produced alanine throughout the study. Myocardial carbohydrate oxidation increased significantly during maximal pacing in normal subjects but not in patients, in whom it always remained below (p less than 0.01) the concurrent rate of myocardial uptake of carbohydrate equivalents (glucose, lactate, pyruvate, alanine). Myocardial energy expenditure was significantly lower in patients than in control subjects at maximal rate-pressure product levels (p less than 0.01). The metabolic pattern in patients with syndrome X therefore is not consistent with classic ischemia, although differences in the net exchange of circulating substrates (glucose, pyruvate, alanine) can be demonstrated. Thus, in patients with syndrome X, the symptoms, electrocardiographic signs and impairment in the increase in great cardiac vein flow during pacing coexist with preserved global and regional left ventricular function and myocardial energy efficiency.

Angina Pectoris↗
PubMed1990

Natural course of treated pulmonary embolism. Evaluation by perfusion lung scintigraphy, gas exchange, and chest roentgenogram.

Perfusion lung scintigrams, pulmonary gas exchange data, and chest roentgenograms were obtained in 33 patients during acute embolism and over the following six months in order to assess their clinical usefulness in monitoring the effect of therapy. To this purpose, the measurement of pulmonary gas exchange and the presence of chest x-ray findings were compared with perfusion lung scintigraphic abnormalities both at diagnosis and after 7, 30, and 180 days during treatment. More than 50 percent of the pulmonary arterial tree was obstructed at diagnosis, and a large part of perfusion recovery was complete within the first month. All of the gas exchange parameters were abnormal at diagnosis, and the rate of their improvement was related to that of perfusion recovery. Interestingly, PaO2st (ie, PaO2 corrected for hyperventilation) and VE tended to return to normal during the first month as a consequence of the progressive recovery of perfusion, whereas oxygen and carbon dioxide gradients and physiologic dead space showed the persistence of some abnormalities six months after diagnosis. Significant correlations were observed between the number of ULSs evaluated on the perfusion lung scintigram (and considered an index of the severity of pulmonary embolization) and all of the gas exchange parameters at diagnosis (correlation coefficients averaged from 0.41 to 0.73) and after 7 and 30 days. The enlargement of the right descending pulmonary artery and particularly the "sausage" sign and the Westermark sign were significantly associated with a higher degree of gas exchange impairment and with a more severe embolization. In conclusion, this study demonstrates that perfusion lung scintigraphy has a primary role in monitoring the recovery of patients with pulmonary embolism under treatment. Moreover, the chest roentgenogram may help in this purpose. A second major result is that the simple measurement of some gas exchange parameters may allow the assessment of functional recovery of these patients, thus giving additional information about the effect of therapy.

Carbon Dioxide↗
PubMed1986

Ultrasonography in the evaluation of osteogenesis in fractures treated with Hoffmann external fixation.

The possibilities of ultrasonography demonstrating periosteal callus and osteogenesis at the fracture focus are described. Illustrative cases are presented and the advantages of this technique are discussed. It is emphasized that ultrasonography is a noninvasive technique that may be repeated as often as is necessary. It provides images of appositional periosteal callus much earlier than radiography, thus facilitating early evaluation of the treatment employed.

Femoral Fractures↗
PubMed1985

The effect of portocaval shunt on hepatic glycogen stores during fasting.

The effect of a prolonged fast was studied in surgically portocaval shunted (PCS) rats. This shunt excludes the liver from the direct effect of pancreatic and enteric hormones, thus facilitating the study of the biochemical and metabolic effects of these hormones. In portocaval shunted rats, liver glycogen was lower than that of control rats, and remained unaffected during fasting. No remarkable difference was observed in blood glucose, plasma and liver free fatty acids and blood ketone bodies. Among blood nitrogen compounds, total protein, alanine and urea did not show any significant variation, while, in PCS rats, the initial low levels of creatinine resulted in an increase after fast. Skeletal muscle protein decreased only slightly in control rats, while their loss was remarkable in PCS rats. The possibility of a differential activation of gluconeogenesis and glycogenolysis in control and PCS rats is discussed.

Animals↗
PubMed1985

"Interpotential" mounting in monolateral Hoffmann fixation.

The authors carried out an experimental study to quantify the stability of monolateral fixation devices of the Hoffmann type. The technical tests indicated that changes were needed in the geometry of the devices; these were achieved by designing a junction piece which enables the transfixion pins and the smooth stabilization rod to remain in the same plane, while leaving the rest of the instrumentation unchanged. The use of this component makes the fixation device more stable and lighter than the classic monolateral devices commonly used. It also prevents the separation and rotation of the fragments that can occur when rods not in the same plane are subjected to compression.

Biomechanical Phenomena↗
PubMedDate not supplied

Cemented hip prostheses: modular screw system.

The long-term results of 21 patients treated with modular screw cementless hip prostheses are reported. An examination of periprosthetic osteogenesis and function evaluated by gait analysis revealed good incorporation of the prosthesis and good clinical results in all of the cases studied.

Bone Cements↗