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Biomedical subjects

A Benedetti

Publications and source records attributed to A Benedetti.

At least 199 records · Page 11Linked to original sources
PubMed1984

Spontaneous intracerebral hematomas: a new proposal about the usefulness and limits of surgical treatment.

We analyzed the volume of 132 spontaneous supratentorial intracerebral hematomas calculated with computed tomographic (CT) scans and related it to the clinical condition of the patients on admission and to the outcome at their discharge from the hospital (1 to 3 months after the ictus). Fifty patients were operated on, and 82 received only medical treatment. In evaluating outcome, we were more interested in survival than its quality. The main problem is the evaluation and treatment of the many patients who are comatose upon admission (about half of the patients). We concluded that surgical treatment by evacuation of the hematoma increases the percentage of survival of comatose patients with a hematoma volume between 26 and 85 ml.

Cerebral Hemorrhage↗
PubMed1984

Loss of lipid peroxidation as a histochemical marker for preneoplastic hepatocellular foci of rats.

Since it is known that tumor cell membranes have lost the capacity to undergo lipid peroxidation, it seemed of interest to investigate whether the loss of susceptibility to lipid peroxidation represents a tumoral marker appearing in preneoplastic cells together with the other known tumoral markers. A histochemical technique was developed to detect lipid peroxidation in individual cells of liver sections exposed to effective prooxidants. The technique was based on the detection of protein-bound aldehydes (alkenals) with the use of the Schiff's reagent. The latter reagent can also detect carbonyl function present in acyl residues of peroxidized phospholipids of cellular membranes. Liver preneoplastic foci were obtained in rats by the i.p. administration of diethylnitrosamine and of 2-acetylaminofluorene in the diet. Frozen sections of the liver, incubated in the presence of reduced nicotinamide adenine dinucleotide phosphate:iron revealed the presence of areas in which lipid peroxidation had not been induced (Schiff-negative areas). These areas corresponded strictly, in serial sections, to areas that were strongly positive to gamma-glutamyltranspeptidase.

2-Acetylaminofluorene↗
PubMed1984

On the mechanisms of the inhibition of calcium sequestering activity of liver microsomes in bromotrichloromethane intoxication.

The mechanisms by which the in vivo intoxication with BrCCl3 inhibits the calcium sequestration activity of liver microsomes were studied. The initial rate of Ca2+ transport is inhibited by nearly 50% in the intoxicated rats as compared to the controls; this indicates that the active transport of Ca2+ is markedly affected by the intoxication. The microsomal ATPase activities both in the presence and in the absence of Ca2+ were not decreased at all in the intoxicated animals. However, the Ca2+-dependent extra ATP-hydrolysis shows a different kinetics in the BrCCl3-poisoned rats with respect to the controls. The release of Ca2+ from Ca2+-loaded liver microsomes is higher in the intoxicated animals. It seems therefore that the increased permeability of the membrane to Ca2+ contributes to some extent to the haloalkane-induced inhibition of the calcium sequestration activity of liver microsomes.

Adenosine Triphosphate↗
PubMed1984

[Stereotaxic irradiation with a linear accelerator].

At least two fundamental requirements must subsist for every stereotaxic radiotherapy treatment: 1) a capacity to administer extremely high doses of radiation to small areas which have been precisely defined in three dimensions; 2) the presence of a steep gradient between adjacent isodose curves so that damage to the tissues close to the target may be reduced to the minimum. The authors have built a special stereotaxic device for the fixing of the head of the patient (together with the chosen intracranial target), once the indispensable neuroradiological evaluations and bioptic controls have been effected, at the isocenter of a linear accelerator (Varian Clinac 4). Once the dimensions of the collimator have been chosen in accordance with the volume and the three dimensional conformation of the target and the dose to be administered has been decided upon in accordance with the histological nature of the lesion, both the linear accelerator and the patient are rotated about the isocenter of the therapy unit. It this way it is possible to reach extremely high dosages with very steep isodose gradients, centered exclusively upon the target ("gamma knife"). The procedure employed is described in full. The dosimetric evaluations which preceded the use of the set-up in clinical practice are illustrated as well. The advantages that this technique offers when compared with interstitial brachytherapy and/or Leksell's radiosurgical procedures are stressed. The described procedure, which is entirely bloodless and thus applicable also to high vascularized lesions, has so far been used in a limited series of cases.

Brain Diseases↗
PubMed1983

[Evaluation of platelet function and coagulation in deafness and sudden vestibular disorders].

Thirty-five patients affected by acute vestibular dysfunction (A.V.D.) and/or sudden deafness (S.D.) were studied. Twenty-seven of them presented, as major component of the clinical disorder, a vestibular dysfunction, eight a sudden deafness. The control group was matched for sex, age, smoking habit and family history of diabetes and myocardial infarction. In all the subjects the following tests were carried out: platelet aggregation (Born's method), PF3 (Spaet and Cintron), PF4 and BTg (RIA), aPTT, AT III, cholesterol and triglycerides. The results indicate in the patients group increase of P.A.: SAV = 27 vs 43% (p = 0.03) at 1.2 X 10(-6) M ADP, a larger availability of PF3 in PPP and PRP, increase of PF4: 7.2 vs 17.2 (p = 0.01) and BTg: 32.4 vs 49.1 (p = 0.009). The data indicate in A.V.D. and S.D. a platelet hyperactivity; if so, an antiplatelet therapy may be reasonable.

Adult↗
PubMed1983

Aneurysm of azygos anterior cerebral artery.

A case of an aneurysm of an azygos anterior cerebral artery operated on successfully is reported. The embryo-genetic features of this rare vascular malformation and the diagnostic and surgical problems are discussed.

Cerebral Angiography↗
PubMed1983

Cognitive outcome and early indices of severity of head injury.

Neuropsychological outcome of 100 patients with severe head injuries is correlated with their clinical condition on admission. The aim of this paper is to estimate the reliability of several early indices of brain damage severity in formulating a prognosis. Both the Glasgow Coma Scale and the neurological syndrome involved appeared to be highly reliable in this respect. The duration of coma and of posttraumatic amnesia was not as significant. Since these two parameters were assessed when reviewing the cases, they have to be considered only as retrospective judgments. The findings emphasized the importance of reflex ocular motility and the value of recording electroencephalographic (EEG) activity, particularly EEG sleep patterns. The relationship between rapid eye movement sleep impairment and cognitive defects was highly significant. Analysis of surgical observations demonstrated that purely compressive expanding lesions were not as harmful as parenchymal damage. Of paramount importance was the time lapse between injury and surgery, since secondary lesions may develop and affect cerebral areas that are involved both in sleep organization and in memory functions.

Brain Injuries↗
PubMed1982

Detection of carbonyl functions in phospholipids of liver microsomes in CCl4- and BrCCl3-poisoned rats.

Since the peroxidative cleavage of unsaturated fatty acids can result in either the release of carbonyl compounds or the formation of carbonyl functions in the acyl residues, evidence for the presence of carbonyl groups in liver microsomal phospholipids was searched for in in vivo conditions (CCl4 and BrCCl3 intoxications) in which peroxidation of lipids of hepatic endoplasmic reticulum had been previously demonstrated. The spectrophotometric examination of 2,4-dinitrophenylhydrazine-treated phospholipids of liver microsomes from the intoxicated animals showed absorption spectra similar to those observed for the dinitrophenylhydrazones of various carbonyls. Similar spectra, although magnified from a quantitative point of view, were also observed with 2,4-dinitrophenylhydrazine-treated phospholipids of liver microsomes peroxidized in the NADPH-Fe-dependent system. A time-course study of microsomal lipid peroxidation showed that the amount of 2,4-dinitrophenylhydrazine-reacting groups (carbonyl functions) in phospholipids of liver microsomes increases with the incubation time and is correlated to the amount of malonic dialdehyde formed in the incubation mixture. The kinetics of the production of 4-hydroxynonenal was somewhat similar to that of malonic dialdehyde formation. In both the in vivo conditions (CCl4 and BrCCl3 intoxications) the amount of carbonyl functions in microsomal phospholipids, which was higher in the BrCCl3-intoxicated animals as compared to the CCl4-poisoned ones, was close to that found in the vitro condition in which lipid peroxidation is induced by 6 microM Fe2+. The possible pathological significance of formation of carbonyl functions in membrane phospholipids is discussed.

Animals↗
PubMed1982

Evidence for aldehydes bound to liver microsomal protein following CCl4 or BrCCl3 poisoning.

Since it has been demonstrated in previous studies that peroxidation of liver microsomal lipids leads to the production of aldehydes provided with cytopathological activities--namely 4-hydroxyalkenals--evidence was searched for aldehydes bound to microsomal protein in in vivo conditions (CCl4 and BrCCl3 intoxications) in which peroxidation of lipids of hepatic endoplasmic reticulum had been demonstrated previously. The spectrophotometric analysis of 2,4-dinitrophenylhydrazine-treated non-lipoidal residues of liver microsomes from the intoxicated rats shows absorption spectra similar to those observed for the dinitrophenylhydrazones formed in the reaction of alkenals with -SH groups of proteins or low molecular weight thiols. Similar spectra, although magnified from a quantitative point of view, were obtained either with liver microsomes allowed to react with synthetic 4-hydroxynonenal or with liver microsomes peroxidized in the NADPH-Fe-dependent system. A time-course study of microsomal lipid peroxidation shows that the amount of 2,4-dinitrophenylhydrazine-reacting groups in the non-lipoidal residue of liver microsomes increases with the incubation time and is correlated to the amount of thiobarbituric acid-reacting products formed in the incubation mixture. In both the in vivo conditions (CCl4 and BrCCl3 intoxications) the amount of 2,4-dinitrophenylhydrazine-reacting groups in the non-lipoidal residue of liver microsomes increases from 15 min up to 2 h after poisoning and is higher, in every instance, in the BrCCl3-intoxicated animals compared to the CCl4-poisoned ones. Experiments carried out to ascertain the reliability of the spectrophotometric detection of protein-bound alkenals showed that in the in vitro system in which liver microsomes are allowed to react with 4-hydroxynonenal there is a good agreement between the binding value that can be calculated from the absorption spectrum and the binding value obtained by using labelled 4-hydroxynonenal.

Aldehydes↗
PubMed1982

[Endosteal hyperostosis with dominant transmission. Description of 8 cases in 3 generations of the same nuclear family].

The authors report on 8 patients with the dominant type of endosteal hyperostosis (Worth's disease), found in the same kindred over 3 generations. Three were males, five females, from 5 to 49 years of age. Major radiographic features were an increased density of bones of the skull and spine, with thickening of the diaphyseal cortex of tubular bones, without any change in remodeling. Seven patients were almost asymptomatic. A decompressive craniotomy had been performed in one, who showed a compression of the 2nd, 5th and 8th cranial nerves. Blood alkaline phosphatase was normal. The bone density increases with age, but in spite of this the clinical course if milder than in recessive type of generalized cortical hyperostosis (Van Buchem's disease, as reported in the 35 cases of endosteal hyperostosis (dominant type) previously described.

Adolescent↗
PubMed1981

[Mechanism of action of carbonyl compounds (4-hydroxyalkenals) derived from the peroxidation of hepatic microsomal lipids].

When carbonyl compounds released during the NADPH-Fe dependent peroxidation of liver microsomal lipids and identified as 4-hydroxyalkenals (almost entirely 4-hydroxynonenal) are incubated with liver microsomes, a substantial amount of these products can be recovered bound to the microsomal protein, by allowing the microsomal protein to react with 2,4-dinitrophenyl-hydrazine. Concomitantly with the binding a decrease in the "exposed" and total -SH groups is stechiometrically accounted for by the amount of carbonyl compounds bound to the microsomal protein. Still in concomitance with the binding, the G-6-Pase activity of the microsomes markedly decreased. Therefore a mechanism similar to that described (12) for the binding of 4-hydroxyalkenals to -SH groups of protein and enzymes can be postulated.

Aldehydes↗
PubMed1981

[Cytotoxic effects of carbonyl compounds (4-hydroxyalkenals) derived from peroxidation of hepatic microsomal lipids on isolated hepatocytes].

Carbonyl compounds released during the NADPH-Fe dependent lipid peroxidation and identified as 4-hydroxyalkenals (almost entirely as 4-hydroxynonenal), when incubated with isolated hepatocytes, produce loss of viability in 95% of the cells, as measured by the trypan blue exclusion test. They also produce an almost complete permeabilization of the plasma-membrane, as measured by the test of the permeability to NADH. concomitantly with the permeabilization of the plasma-membrane, a marked release of enzymes (lactate dehydrogenase and glutamate-pyruvate transaminase) from the hepatocytes occurs. These and other activities of the above mentioned carbonyl compounds suggest the possibility that these products represent some of the effective mediators of the liver injury produced by those toxins, such as CCL4, which promote the peroxidation of membrane lipids.

Alanine Transaminase↗