Biomedical subjects

R Budini

Publications and source records attributed to R Budini.

9 recordsLinked to original sources

PubMed1999

Chemiluminescent determination of xanthine oxidase activity in milk.

A chemiluminescent method for determining xanthine oxidase (XOD) activity was developed and applied to the assay of milk enzyme activity using a photomultiplier luminometer. Various kinds of milk and cream samples were analysed for XOD content. In pasteurized milk, XOD activity depended on the fat content and in UHT milk it disappeared owing to the heat treatment. Milk sample preparation was very simple, requiring only homogenization at 40 degrees C followed by a 1:10 dilution with UHT ('XOD-free') milk. The assay was carried out at 25 degrees C. The response obtained from XOD standard solutions in milk was linear from 0.1 to 500 enzyme units (U) l-1, but for the actual milk samples values ranged only from 1 to 135 U l-1. The detection limit at 2 SD was 0.1 U l-1 in milk, while in buffer it was 100 times lower. The intra-assay and interassay CV for XOD activity in milk were 6-12%.

Animals↗

PubMed1991

Methodological problems of direct bioluminescent ADP assay in platelets and erythrocytes.

We have developed a method for ADP bioluminescent measurement in platelets and erythrocytes which complements our previous method for ATP assay. When the different parameters of the system under investigation are taken into account, a linea range between 10(-9) and 10(-7) g/ml can be obtained without incubation or troublesome extraction. This makes the method easy and useful for identifying any disease-induced alterations in ATP and/or ADP levels in these blood cells. The data obtained correlate well with those of a bioluminescent method requiring extraction with ethanol/EDTA and incubation, giving the reference intervals of 3.5-5.5 mumol/10(11) PLT for ATP determination and 1.9-3.7 mumol/10(11) PLT for ADP determination in platelets, and 3.2-3.8 mumol/g Hgb for ATP determination and 0.56-0.73 mumol/g Hgb for ADP in erythrocytes. This assay was applied to quality control on blood bags in transfusion centers and proved to be a rapid and reliable method for testing the viability of stored blood cells.

Adenosine Diphosphate↗

PubMed1987

External GSSG enhances intracellular glutathione level in isolated cardiac myocytes.

The addition of external GSSG at concentrations in the range 50-500 microM produces in isolated adult rat heart myocytes an increase of GSH level and only a slight increase of GSSG level. On the contrary, external GSH at the above same indicated concentrations did not change the cell glutathione pool. The pretreatment of the cells with diethylamaleate depleted the myocytes of glutathione and enhanced the GSSG-induced replenishment effect on GSH level. On the contrary, the addition of GSH did not increase the concentration of cell glutathione. The level of cell GSH in diethylmaleate-treated myocytes was not increased after 30 min of incubation with cysteine, or acetylcysteine. The GSSG induced-stimulation on GSH level was not inhibited by buthionine sulfoximine, an inhibitor of glutathione synthesis. On the contrary, this stimulatory effect was inhibited by N, N-bis(2-chloroethyl)-N-nitrosourea, an inhibitor of glutathione reductase, or partially, by the remotion of glucose from the incubation medium. These results support the idea that the isolated adult rat heart myocytes are able to utilize external GSSG in order to increase the intracellular glutathione pool, probably through the reduction of the imported GSSG to GSH.

Acetylcysteine↗

PubMed1985

Involvement of superoxide radicals on adrenochrome formation stimulated by arachidonic acid in bovine heart sarcolemmal vesicles.

Highly purified sarcolemmal membranes prepared from bovine heart muscle produced superoxide radicals, especially when incubated with NADPH or NADH, as revealed by the oxidation of adrenaline to adrenochrome. The reaction was inhibited by superoxide dismutase or by heat denaturation of the sarcolemmal vesicles. Less evident was the inhibitory effect shown by catalase, while mannitol, deferoxamine or dicumarol were uneffective. The formation of adrenochrome was an oxygen-dependent reaction with a Km for adrenaline of 8-10 microM. Moreover, the reaction was inhibited by preincubating the sarcolemmal membranes with propranolol, while the alpha-antagonist phentolamine was without effect. Adrenaline oxidation was unaffected by the presence of exogenous linolenic acid or methylarachidonic acid, while arachidonic acid, with a Km for this reaction of 175 microM, showed a marked stimulatory effect. This activation was suppressed by superoxide dismutase, catalase and NaCN, while mannitol was without effect. Moreover, the reaction was blocked by the cyclooxygenase inhibitor indomethacin, differently from the lipooxygenase inhibitor nordihydroguaiaretic acid. Also, the incubation of the sarcolemmal vesicles with phospholipase A2 and calcium produced a stimulation of adrenochrome formation which was partially suppressed by albumin. In the experiments using arachidonic acid or phospholipase A2, the addition of indomethacin blocked the adrenaline oxidation. These results indicate that arachidonic acid accentuated the heart sarcolemmal adrenochrome formation presumably by participating in the cyclooxygenase reaction.

Adrenochrome↗

PubMed1981