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Biomedical subjects

G Donati

Publications and source records attributed to G Donati.

At least 91 records · Page 5Linked to original sources
PubMed1995

Nitric oxide controls arteriolar tone in the retina of the miniature pig.

PURPOSE: Experimental evidence indicates that the retinal microcirculation is mainly controlled by factors released from the tissue surrounding the arterioles. This study explores whether nitric oxide (NO), a possible factor, is released in the retina and controls the arteriolar tone. METHODS: Using a NO microprobe, the authors measured [NO] in the preretinal vitreous of miniature pigs as a function of distance from the retinal surface. Additionally, the NO-synthase inhibitor nitro-L-arginine was pressure injected. Finally, the retinal pool size of arginine and its biosynthesis from 14C(U)-glucose were biochemically assessed on retinal tissue and acutely isolated Müller cells. RESULTS: At the retinal surface, [NO] measured 6 to 9 microM, and, in the vitreous, it fell to zero approximately 180 microns away from the retina. Therefore, NO is degraded faster in the vitreous (65 to 80 microM.minute-1) than in aqueous solution. Light flicker stimulation of the dark-adapted retina induced a reversible increase of [NO] (approximately 1.6 microM). Preretinal juxta-arteriolar microinjections of nitro-L-arginine (0.6 mM) induced a segmental and reversible arteriolar vasoconstriction of 45%; in contrast, intravenous infusion of nitro-L-arginine had no measurable effect on arteriolar diameter. The retinal pool size of arginine was small (< or = 200 microM), but there was an important rate of arginine biosynthesis in Müller cells. CONCLUSIONS: These results strongly suggest that cells in the retina, other than endothelial cells, produce and release NO, which in turn controls the basal dilating arteriolar tone in the inner retina.

Animals↗
PubMed1994

[The role of nitric oxide in retinal vasomotor regulation].

Nitric oxide (NO) is one of the most important messenger molecules dilating blood vessels in response to neurotransmitters and serving itself as a neurotransmitter in the brain. We explored its role in the retinal vascular regulation using a sensitive and specific NO microsensor and local perivascular microinjections of NO-synthase inhibitor (nitro-L-arginine in the intact eye of anesthetized miniature pigs. Our findings suggest that NO release is involved in the regulation of basal vascular tone in the inner retina. In contrast hypercapnia and hypoxia induce vasodilatation in an NO independent mechanism.

Animals↗
PubMed1993

[A clinical study to determine the optimal dosage of ST-679 in the treatment of rheumatic diseases].

A study was performed with 60 patients, affected by acute phase rheumatological pathology, in order to determine the optimum posology of ST-679 administered orally. The 60 patients were divided into 4 groups: 3 treated with ST-679 at different dosages (group 1 = 600 mg/die; group 2 = 1200 mg/die; group 3 = 1800 mg/die) and one with placebo (group 4 = 600 mg/die). The highest dosage employed (1800 mg/die) performs an excellent therapeutical activity which is equivalent to that at the 1200 mg in reducing pain symptomatology, but on the average less tolerated. The 600 mg dosage was less efficacious with respect to the two higher doses.

Acute Disease↗
PubMed1993

[An evaluation of the therapeutic activity and tolerance of ST-679 in patients with osteoarthritis at different sites. A controlled double-blind study vs tolmetin].

A multicentered study was carried out, under double-blind conditions, on 160 elderly patients afflicted with differently localized symptomatic osteoarthritis, for the purpose of evaluating the therapeutical efficacy and tolerability of ST-679 (per-os at a dose of 1200 mg pro die in 80 patients) and to compare them with those of tolmetin (per os at a dose of 1200 mg pro die in 80 patients). It was demonstrated that ST-679 was significantly active on all of the clinical parameters of the illness already recorded after a month of treatment. ST-679 was always excellently tolerated as shown by the scarce incidence of adverse reactions. Results of laboratory tests, of tests for hidden blood in the feces and of a gastroduodenoscopy confirmed the excellent biological and gastric tolerability of ST-679. ST-679 demonstrated, moreover, a significantly better tolerability with respect to tolmetin.

Administration, Oral↗
PubMed1989

[Myocardial perfusion in coronary disease: thallium-201 planar scintigraphy].

This research evaluated the diagnostic and analytic effectiveness of 201-thallium imaging in a group of patients with coronary artery disease, each one of them with different localization, extent and number of coronary vessel obstructions. The thallium-201 imaging was performed immediately after ergometric test and repeated 4 hours later. In a large percentage of patients thallium-201 imaging of reversible and irreversible perfusion defects have been found; thallium-201 scintigraphy showed a greater sensitivity than exercise ECG. With particular evidence 201-Tl imaging showed perfusion defects in a high percentage of patients with obstruction of one and two coronary vessels; in these patients, in the former especially, the results of exercise ECGs showed a lower sensitivity. Both thallium-201 and exercise ECG had a similar sensitivity in patients with obstruction of three coronary vessels. In patients with obstruction of one or two vessels, thallium-201 imaging clearly showed a regional hypoperfusion corresponding to the specific perfusion coronary vessels, while exercise ECG gave aspecific topographic results. Irreversible perfusion defects resulted corresponding to the myocardial segments that were infarcted, but were also observed in patients without previous myocardial infarction.

Adult↗
PubMed1988

Extensive atrazine pollution of drinking water in the Lombardia region and related public health aspects.

Introduced in 1957, atrazine is a herbicide used worldwide, mainly in corn cultivation areas for weed control. It is only slightly volatile, is highly soluble in water, and is moderately persistent in topsoil, where it is strongly absorbed to organic carbon. Because of these properties, atrazine can leach to ground water and persist for a long time. This work presents the results obtained so far from an investigation initiated because of an emergency situation in the Lombardia Region of Italy caused by the occurrence of levels of atrazine in drinking water exceeding those established by the European Economic Community and Italian regulations. Water samples from almost 3000 wells were analyzed in different laboratories of the Lombardia Region. Atrazine contamination occurred in a significant number of the wells examined. Examination of the analytical data overall leads to the conclusion that the agricultural use of atrazine in the Lombardia Region is a serious source of ground water contamination. In some areas other factors may be responsible for the contamination of ground water (for instance, industrial activities and/or uncontrolled waste discharges). Geological and hydrological characteristics may play an important role in ground water contamination. Purification systems containing active charcoal seem to be highly efficient in removing atrazine from contaminated water.

Atrazine↗
PubMed1987

Human immunodeficiency virus (HIV) seropositivity in intravenous (i.v.) drug abusers in three cities of Italy: possible natural history of HIV infection in i.v. drug addicts in Italy.

The prevalence of human immunodeficiency virus (HIV) antibodies and the symptoms induced [persistent generalized lymphadenopathy (PGL), AIDS-related complex (ARC), acquired immunodeficiency syndrome (AIDS)] was evaluated in several groups of intravenous (IV) drug abusers in three large Italian cities (Milan, Bologna, and Rome). The earliest evidence of seropositivity in sera collected from patients with acute viral hepatitis dates back to 1979 in Milan and to 1981 in Bologna with peaks in 1983 in both cities. In two groups of IV drug addicts on methadone-maintenance treatment at assistance centers, the prevalence of seropositivity differed sharply between Rome (33.3%) and Milan (69.3%) in 1985. Rates of seroconversion were also found to be higher in Milan than in Bologna and Rome. When a population of IV drug abusers voluntarily attending centers for surveillance of AIDS and/or ARC were investigated, high levels (range 55.2-81.5%) of seropositivity were found in the three cities. ARC prevalence among seropositives was very high (range 48.1-64.2% in 1985) in the three cities. The evolution rate to AIDS in Milan was higher among those attending a center for AIDS surveillance (7.4%) than among those attending an assistance center for methadone treatment (0.9%). These data are compatible with the hypothesis that virus infection among IV drug abusers originated in and then spread widely in Northern Italy (Milan first and then Bologna). Both the first appearance and subsequent spread of virus infection are in keeping with the reported occurrence of AIDS cases in the corresponding three regions of Milan, Bologna, and Rome.

AIDS-Related Complex↗
PubMed1987

Treatment of hemodialysis-related porphyria cutanea tarda with small repeated phlebotomies.

Phlebotomy is generally thought to be contraindicated in porphyria cutanea tarda (PTC) associated with hemodialysis for the anemia which is often present in uremic patients. We report a patient with a severe form of hemodialysis-related PTC and biochemical parameters suggestive of iron overload in whom treatment with small repeated phlebotomies was well tolerated without any significant worsening of the anemia and gave marked biochemical improvement and complete clinical remission.

Aged↗
PubMed1979

A computerized cancer patient information system.

The purpose of this study was to realize a computer system for cancer data automatic processing. A clinical research in oncological practice is usually time consuming and often not reliable or deceiving because of a number of various errors. Until now, only a few information systems have been specifically designed for cancer data processing, and these have a limited capacity of autonomous data elaboration. Our system, based on an original computer program, can compile, store and process essential data on cancer diseases, with a high degree of reliability and high speed of elaboration. Input and output of this system are simplified and user oriented, without limitations for the subject at study on clinical research, and no particular training of the physicians involved is necessary.

Computers↗
PubMed1974

[Reliability of N.M.R. employed in evaluating refrigerating mixtures organic solvents R 22 (Author's transl)].

In a previous work the existence of an hydrogen bond between the difluoromonochloromethane (R 22) and the diethylesters of alpha-omega dicarboxylic acids was pointed out. In the present paper, the influence on absorption of substituents for the hydrogen of the CH2 has been studied in a single compound (diethylmalonate). The results show that electron acceptor substituents obstruct the forming of the hydrogen bond while electron donor substituents improve it.

Electron Transport↗