Biomedical subjects

M Scarpa

Publications and source records attributed to M Scarpa.

98 records · Page 6Linked to original sources

PubMed1984

Generation of superoxide ion in human red blood cell lysates.

The generation of superoxide ion in human red blood cell lysates was investigated by an experimental method employing Cu,Zn superoxide dismutase as O2- scavenger and EPR to probe the oxidation state of the enzyme. The average value of the O2- flux in the erythrocytes of 8 normal individuals was (2.02 +/- 0.97) X 10(-8) M S-1. A progressive saturation of the rate of O2- production was found increasing PO2, KM = 1.04 X 10(-4) M, while the autoxidation of oxyhemoglobin did not contribute significantly to the measured O2- production.

Adult↗

PubMed1984

An NMR study of the oxidation state of Cu,Zn superoxide dismutase in human red blood cells.

The oxidation state of Cu,Zn superoxide dismutase was investigated by 19F-NMR spectroscopy in intact red blood cells and in their lysates. The superoxide dismutase concentration was determined in the red cells both by activity and by F- nuclear relaxation rate measurements and the results obtained showed that the high relaxation rate of F- in erythrocytes is mainly due to the presence of superoxide dismutase. The relaxation rate of F- was unaffected or slightly increased by the addition of a superoxide ion generating system to the cells or to their lysates so indicating that superoxide dismutase is fundamentally in steady state. The results are discussed in terms of the possible reactions of the enzyme in erythrocytes.

Erythrocytes↗

PubMed1983

Superoxide ion as active intermediate in the autoxidation of ascorbate by molecular oxygen. Effect of superoxide dismutase.

The oxidation of ascorbic acid by molecular oxygen was investigated by optical and magnetic resonance methods in the presence and in the absence of copper and iron complexes. The results show that one superoxide ion is generated for each oxidized molecule of ascorbate. The effect of addition of Cu,Zn superoxide dismutase, which at concentrations higher than 10(-7) M halves the oxidation rate, is discussed and a reaction mechanism is proposed. An upper limit for the kinetic rate constant of the reaction between the ascorbate radical and the superoxide ion is reported.

Animals↗

PubMedDate not supplied

NMR method for superoxide dismutase assay in brain and liver homogenates.

A method for copper- and manganese-containing superoxide dismutase (Cu- and MnSOD) assay in tissue homogenates such as liver and brain, based on the measurement of the longitudinal nuclear relaxation time (T1) of F-, has been developed as a preliminary approach to in vivo measurement of these enzymes. The relaxation rate of F-, which increases linearly with the SOD concentration, also depends on the oxidation state of the metal ion present in the active site of the enzyme. The relaxivity values of the oxidized, reduced and turnovering CuSOD were found to be 9.6 x 10(6), much less than 1 x 10(2) and 5.2 x 10(6) M-1 s-1, respectively, while for MnSOD the corresponding values were 2.9 x 10(6), 4.2 x 10(6) and 3.6 x 10(6) M-1 s-1, respectively. These high relaxivity values allow the detection of SODs in brain and liver homogenates where, under aerobic conditions, these enzymes appear in the steady-state. The contribution of the two types of SOD to the F- relaxation rate in the homogenates was measured by addition of either diethyldithiocarbamate or cyanide, both of which selectively inhibit the CuSOD. The comparison between NMR and activity data confirmed the possibility of carrying out accurate and precise measurements of SODs in homogenates by NMR.

Animals↗

PubMedDate not supplied

[Lombardy regional project: prevention of occupational tumors].

In Lombardy, the regional project "Prevention of occupational cancers" is ongoing. The main objectives of this project are to identify work environments in which there might be a possible exposure to carcinogenic substances and to elaborate preventive measures. A casual sample of 250 working settings representing the different economic activities has been selected and evaluated. The 10% of the examined workplaces showed a possible exposure to chemical carcinogens. The most common carcinogens were trichloroethylene, preparation of plastics materials containing acrylonitrile-butadiene-stirene, formaldehyde, wood dust, hexavalent chromium, silica and polycyclic aromatic hydrocarbons. Galvanic industries, Bitumen production and placing companies and Plastics processing plants will be studied for environmental and biological monitoring and for the development of preventive measures.

Humans↗

PubMedDate not supplied

13C-octanoic acid breath test in functional and organic disease: critical review of literature.

The 13C-octanoic acid breath test is considered a useful tool to measure gastric emptying both in physiological and pathological conditions. Many studies have concerned functional dyspepsia. Recently, breath test has been used in predicting a delayed gastric emptying in subsets of dyspeptic symptoms. In detail only postprandial fullness and vomiting are resulted significantly correlated with delayed solid emptying. Besides in the patients with dyspepsia and irritable bowel syndrome associated, intestinal disturbances did not seem to contribute to delay gastric emptying. In diabetic patients octanoate test has confirmed the percentages of delayed emptying obtained by means of scintigraphy. In other organic states (celiac disease, cirrhosis, renal failure, neurological disease, etc) most of reports have proved a delayed emptying of solids. In GERD and ulcer disease gastric function is resulted normal, being accelerated in distal gastrectomy and in hyperemesis gravidarum. From pathophysiological point of view Helicobacter pylori, extrinsic autonomic neuropathy (apart from diabetes) and autoimmunity do not seem to relate with gastric emptying, both in functional and organic disease.

Breath Tests↗

PubMedDate not supplied

Pseudotumor cerebri: clinical features and evolution.

Risk factors, neurological, neuroradiological and ophthalmological features of 13 cases of acute pseudotumor cerebri were studied. After a 53-month period of mean follow-up, ophthalmological complications were taken into consideration: one patient (8%) showed unilateral optic atrophy with complete loss of vision, another subject complained of visual field constriction, and a third one of transient horizontal diplopia. Papilledema, which was present in 100% of the patients in the acute phase, persisted in 62%.

Adolescent↗

PubMedDate not supplied

[Risk factors and short-term prognosis in ischemic and hemorrhagic attacks: review of 503 patients admitted to the Neurologic Clinic of Modena].

Cerebrovascular risk factors, characteristics of the lesion (ischaemia or haemorrhage in the carotid or vertebro-basilar area) and mortality in the acute phase were studied in 503 patients admitted for first stroke. Seventy-five per cent of the patients had an ischaemic lesion and 25% a hemorrhagic one. Most of the ischaemic lesions occurred in patients aged 71-80 years, while haemorrhagic strokes hit subjects aged 61-70 years. Hypertension favors haemorrhage and heart disease and the older age favors ischaemia. Coma at onset negatively influences prognosis; mortality is more frequent among older patients, subjects in coma or with haemorrhagic lesions. Twelve per cent of the patients died in the first three weeks post-onset.

Adolescent↗