Search PubMed⌕ Search

Biomedical subjects

E Giovannini

Publications and source records attributed to E Giovannini.

At least 55 records · Page 3Linked to original sources
PubMed1988

[Doppler echocardiography in assessing mechanical and biological heart valve prostheses].

The study was performed to assess Doppler echocardiographic features of mitral and aortic prosthetic valves of different types with both normal and abnormal function. Two hundred and twenty-three patients with 250 prostheses were studied. Two hundred eight valves (111 mitral, 95 aortic and 2 tricuspid) were considered to be functioning normally after clinical examination, phonocardiography and M-mode and 2D echocardiography. This group enabled us to define normal Doppler echocardiographic findings for different types of prosthesis. In mitral position, peak (p) and mean (m) gradients were lower for disc prostheses and higher for ball and biological prosthetic valves; values of effective orifice area (A), calculated by pressure half-time method, were lower for biological and ball prostheses and higher in disc valves. Results were as follows: St. Jude (p 10.6 mmHg, m 3.9 mmHg, A 2.7 cm2), Duromedics (p 10.6, m 4.3, A 2.8), Björk-Shiley (p 10.4, m 4, A 2.3), Omniscience (p 14.2, m 6.2, A 2.1), Starr-Edwards (p 15.9, m 5.4, A 2.1), Hancock (p 14.7, m 6, A 2), Carpentier (p 13.2, m 5.4, A 1.9). Mild regurgitation, considered "physiological", was found in 2/8 Carpentier valves and in 3/34 St. Jude prostheses. In aortic valves lower peak gradients were found in Lillehei (18.3 mmHg), St. Jude (23.8 mmHg), Björk-Shiley (26 mmHg), Duromedics (27 mmHg) and higher values in Starr-Edwards (30.2 mmHg), Hancock (30 mmHg) and Omniscience (35.5 mmHg) prostheses. Mild regurgitation, considered "physiological", was found in 17% of Omniscience valves, 21% of Hancock, 33% of Duromedics, 45% of St. Jude, 60% of Björk-Shiley prostheses. Hancock mitral valves implanted for over 7 years had a mean gradient higher than valves with a shorter period of implantation (7.6 vs 4.85 mmHg, p less than 0.1), whereas the effective orifice area was similar. Hancock aortic valves implanted for over 7 years had a peak gradient slightly higher than the other group (implantation less than 7 years previously), but the difference was not statistically significant. Forty-two valves (19 aortic and 23 mitral) were considered to be malfunctioning. Regurgitation Doppler signals of malfunctioning valves appeared different from those of "physiological" reverse flow; in the former cases forward gradient was higher than normal prostheses. In stenotic aortic prostheses, peak systolic gradient was greatly increased; in stenotic mitral prostheses, a very significant increase in mean gradient and a great decrease in effective orifice area were found. In 14 patients who underwent surgical re-operation and in the patient who died before operation, Doppler echocardiographic findings were confirmed.(ABSTRACT TRUNCATED AT 400 WORDS)

Aortic Valve↗
PubMed1987

Purification and characterization of two forms of glyoxalase II from the liver and brain of Wistar rats.

Glyoxalase II (S-(2-hydroxyacyl)glutathione hydrolase, EC 3.1.2.6) was purified to homogeneity and separated into two forms (alpha, pI = 8.0; beta, pI = 7.4) from both liver and brain of wistar rats by column isoelectric focusing. These forms were also found to have different electrophoretic mobilities. No significant differences were found between the alpha and beta forms from either source in the relative molecular mass (about 24,000) or in Km values using three substrates. The temperature-inactivation profiles were also similar, the two forms being stable up to 50 degrees C. Chemical modification studies with phenylglyoxal suggest that these enzyme forms probably contain arginine residues near the active site. Inactivation of alpha and beta forms by diethylpyrocarbonate and by photooxidation with methylene blue, and protection by S-D-mandeloylglutathione, a slowly reacting substrate, suggest the presence of histidine at the active site. The alpha and beta forms show different half-life values in inactivation by histidine reagents, which may be due to a difference in the active-site structures of these enzymes. The results probably indicate distinct structures (sequences) for alpha and beta forms.

Animals↗
PubMed1987

A comparative study on glyoxalase II from vertebrata.

S-2-hydroxyacylglutathione hydrolase (glyoxalase II) from the liver of animals belonging to the various vertebrate classes (Oryctolagus cuniculus, Gallus gallus, Python molurus, Rana esculenta, Esox lucius) have been purified from 100,000 g supernatants of liver homogenates, using acetone fractionation and affinity chromatography. Subsequent comparative studies were concerned with some molecular and kinetic properties. Isoelectric focusing gave evidence for a single form of liver glyoxalase II in O. cuniculus, P. molurus and E. lucius, while the enzyme from G. gallus and R. esculenta showed respectively two and three forms with different pI values. All studied enzymes are basic proteins. The relative molecular mass values range from 18,000 to 23,000. The various glyoxalases II do not display markedly different Kn or Ki values. Their stability behavior at different temperatures is also quite similar.

Animals↗
PubMed1985

Alkaline phosphatase in Hirudo medicinalis L.: partial purification and study of certain molecular and catalytic properties.

The authors carried out extraction and purification of an alkaline phosphatase (AP) from Hirudo medicinalis and studied certain characteristics of the enzyme. After homogenizing specimens of H. medicinalis and centrifuging the homogenate at 70,000 g, the enzyme, likely membrane-bound, was obtained in a soluble form by treating the sediment with n-butanol. It was then purified by acetone fractionation and Sephadex G-200 chromatography. A fairly good purification degree was achieved; the enzyme appears to be in a single form and displays a molecular weight of about 268,000. The optimum pH (9.5) is lower than the ones generally observed as regards APs from both Invertebrata and Mammalia. The studied AP displays a strong substrate inhibition, similar to that concerning Metazoa at a higher evolutionary level (Mollusca, Echinodermata). On the contrary, the enzyme-substrate affinity, as shown by Km value (2.447 mM), is lower than as regards APs from more advanced organisms (Echinodermata, Mammalia).

Alkaline Phosphatase↗
PubMed1984

Purification and characterization of four different alkaline phosphatases from Spirographis spallanzanii.

Alkaline phosphatases (APs) present in Spirographis spallanzanii were extracted by water homogenization of butanol treatment. The enzymes solubilized as above were purified by acetone fractionation and then by DEAE-cellulose and Sephadex G-200 chromatography; separation of four AP forms was achieved, which were characterized by studying their molecular and catalytic properties. The various APs differ in molecular weight, electrophoretic mobility, optimum pH, but show similar Km values and substrate inhibition pattern. Kinetic studies carried out with several inhibitors show, in particular, the existence in these APs of a second binding site and suggest a possible role for them in the metabolism of phosphoric esters of the sugars.

Alkaline Phosphatase↗
PubMed1984

[Radioimmunoassay of high specificity for vincristine].

The authors set up a simple and fairly rapid radioimmunoassay for vincristine, that shows a good sensitivity, precision and specificity. In particular, the higher specificity in comparison with other similar dosage techniques is likely due to the marked specificity of the used anti-vincristine serum, which displays a low interference even by molecules with a vincristine-like structure. Therefore, the suggested radioimmunoassay technique seems quite suitable for studying vincristine pharmacokinetics and for monitoring blood levels of this alkaloid in treated patients.

Evaluation Studies as Topic↗
PubMed1984

Purification of S-2-hydroxyacylglutathione hydrolase (Glyoxalase II) from calf brain.

S-2-Hydroxyacylglutathione hydrolase (Glyoxalase II) from calf brain has been purified 8333-times compared to 65,000 g supernatant of brain homogenate. The purification procedure employs Affi-Gel blue and preparative isoelectric focussing and offers a suitable method for the preparation of highly purified enzyme. Calf brain Glyoxalase II is a basic protein with a pl of 7.63 determined by isoelectric focusing. An evaluation of the relative molecular mass by gel filtration gave a value of about 23,000. During the purification procedure a constant Km value of about 0.325 mM was observed. A turnover number of 16,100 min-1 was calculated for the purified enzyme.

Animals↗
PubMed1983

[Clinical aspects and diagnostic criteria in non-obstructive symmetric hypertrophic myocardiopathy].

We describe the clinical data, the standard and Holter electrocardiographic observations, the carotid pulse tracings, the M-mode and B-mode echocardiographic findings and the left ventriculographic aspects of 21 patients with non-obstructive symmetric hypertrophic cardiomyopathy (NOSHCM). NOSHCM was diagnosed when there was echocardiographic and/or left ventriculographic evidence of septal and posterior wall hypertrophy without signs of left ventricular outflow destruction (LVOTO). Compared to the asymmetric hypertrophic obstructive cardiomyopathy (AHOCM), NOSHCM reveals reduced excursion of the posterior wall of the left ventricle, whereas patients with AHOCM have more frequently systolic murmurs and carotid pulse changes suggestive of LVOTO. Proper classification and treatment of NOSHCM are discussed.

Adult↗
PubMed1983

Activity changes of glyoxalases I-II and glutathione reductase in regenerating rat liver.

In regenerating rat liver Glyoxalase I activity shows a significant increase 24-48 hrs after partial hepatectomy. Glyoxalase II activity is significantly increased at 16, 48, and 72 hrs, and shows a transient decrease at 24 hrs after surgery. It is likely that the observed changes in Glyoxalases I and II activities during hepatic regeneration are correlated with the different roles of these enzymes. Glutathione reductase activity, significantly reduced within 8-72 hrs after surgery, does not show any correlation with Glyoxalases. These studied enzyme activities do not display significant changes in the sham-operated animals.

Animals↗
PubMed1982

Partial purification and characterization of an alkaline phosphatase in Helix nemoralis and in Octopus vulgaris.

1. Alkaline phosphatase (AP) present in the liver of Helix nemoralis and of Octopus vulgaris; enzyme was purified by homogenization, ultracentrifugation, n-butanol treatment, acetone fractionation and Sephadex G-200 chromatography. 2. The two enzymes show a similar enzyme-substrate affinity, but differ in several properties (molecular weight, electrophoretic mobility, optimum pH, substrate inhibition); a possible correlation of them with different evolutionary adaptations is suggested. 3. Possible roles of AP in Mollusca are discussed.

Alkaline Phosphatase↗
PubMed1981

[Cardiac echinococcosis. Two-dimensional echocardiographic diagnosis (author's transl)].

A case of cardiac echinococcosis is reported on a 7 year old girl, whose clinical presenting picture was an embolism of the lower limbs. M-mode echocardiography didn't reveal pathological data, whereas two-dimensional (2D) examination in apical position (four-chamber view) diagnosed a cystic structure in the left ventricular free wall. Cardiac surgery confirmed the echocardiographic findings. The necessity to perform all the 2-D sections when there is a clinical suspicion, the possibility to avoid cardiac catheterization and the use of 2-D echocardiography as a screening test in the exposed subjects are emphasized.

Child↗