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Biomedical subjects

G Federici

Publications and source records attributed to G Federici.

At least 127 records · Page 7Linked to original sources
PubMed1988

Acidic glutathione transferase from human heart. Characterization and N-terminal sequence determination.

The anionic glutathione transferase of human heart has been purified to homogeneity by using DEAE-cellulose, affinity chromatography, and FPLC. The enzyme has an isoelectric point at pH 4.75 and has an electrophoretic mobility on SDS-PAGE identical to placental transferase pi, indicating that the heart enzyme is formed by two similar subunits of 23,000 Mr. Upon isoelectric focusing on ampholine PAG plates the enzyme recovered from FPLC gave two bands of activity at pH 4.75 and 4.9 which were reduced to essentially a single band at pH 4.75 after incubation with dithiothreitol. In the immunodiffusion experiment, the heart enzyme gave a positive precipitin line with the antibodies against transferase pi but not with antibodies prepared against the "basic" transferase of human skin or against the "near-neutral" transferase of human uterus. The substrate specificities, the sensitivities to characteristic inhibitors, the amino acid composition, together with the immunological studies, strongly indicate that the anionic enzyme of human heart is closely related to the transferase pi of human placenta. The N-terminal amino acid sequence of the first 48 residues was determined and compared with the N-terminal region of other reported human glutathione transferase sequences. The heart enzyme differs from the placental enzyme in a single residue (Trp instead of Arg in the 28th position) further supporting their similarity.

Amino Acid Sequence↗
PubMed1988

Elevation of glutathione transferase activity in human lung tumor.

Glutathione transferase activity in the cytosolic fractions of human lung tumors was found to be significantly higher than that present in the corresponding non-tumor cytosolic fractions. The relative activities of 'cationic', 'near-neutral' and 'acidic' glutathione transferases of both tumor and non-tumor cytosols were estimated after isoelectric focusing. More than 90% of activity in both tumor and non-tumor cytosols was found to be associated with the 'acidic' (pI 4.6) activity peak. In the chromatogram of tumor tissues the activity associated with the 'acidic' peak was found to be increased in comparison with non-tumor tissues. When the protein fractions associated with the 'acidic' peak of both tumor and non-tumor tissues were tested against the antibodies raised against human placenta transferase (transferase pi) a continuous precipitin line was obtained. An increased amount of immunoreactive glutathione transferase was also found in tumor cytosols as compared with non-tumor cytosols. Thus, our studies indicate that the predominant glutathione transferase of human lung appears to be electrophoretically and immunologically very similar or identical to transferase pi and that the elevation of transferase activity measured in the lung tumor cytosols was mainly due to increased quantity of this isoenzyme.

Adult↗
PubMed1987

A study on the in vitro interaction between tyrosinase and glutathione S-transferase.

The actions of glutathione S-transferase and tyrosinase on the in vitro production of glutathionyl-3,4-dihydroxyphenylalanine and the dopachrome level in the presence of GSH and L-3,4-dihydroxyphenylalanine were studied. No clear evidence of complementarity between tyrosinase and glutathione S-transferase was observed; on the contrary, in the presence of glutathione S-transferase the glutathionyl-3,4-dihydroxyphenylalanine yield was lower than with tyrosinase only, as measured by HPLC. It is concluded that the spontaneous conjugation of GSH with dopaquinone should probably be high enough to scavenge the toxic quinone and to produce precursors for phaeomelanogenesis.

Animals↗
PubMed1987

Increased neuropeptide Y-immunoreactive innervation of aganglionic bowel in Hirschsprung's disease.

The pathophysiology of Hirschsprung's disease has not been fully elucidated but is known to have a neurogenic basis. In recent years, new neural proteins and peptides have been discovered and our aim in this study was to use immunocytochemistry to investigate their involvement in the neuronal abnormalities associated with this condition. Large bowel samples from 9 children undergoing surgery for Hirschsprung's disease were compared with those taken from 8 children with other gastrointestinal diseases but no aganglionosis. Immunocytochemistry was carried out using antibodies to a wide range of neuron specific proteins and peptides. Examination of sections immunostained for the general neuronal markers, protein gene product 9.5, neuron specific enolase and neurofilament triplet proteins, allowed rapid identification of aganglionic segments. Nerves containing vasoactive intestinal polypeptide/peptide histidine methionine (VIP/PHM), galanin, substance P, somatostatin, met-enkephalin or calcitonin gene-related peptide (CGRP) showed a marked reduction in all layers of the aganglionic bowel. However, scattered VIP/PHM immunoreactive fibres were also found in the hypertrophied nerve bundles. In contrast with these reduced peptide-containing nerves, fibres displaying NPY immunoreactivity showed a marked increase in all aganglionic segments, particularly in the circular muscle where few are found normally. Our findings shed further light on the neurobiology of aganglionic bowel and suggest that immunostaining of neural proteins and the peptide NPY can aid rapid histopathological diagnosis of congenital aganglionosis.

Child, Preschool↗
PubMed1987

Glutathione transferase activity during Bufo bufo development.

High levels of glutathione transferase activity were measured during the development of the embryos of Bufo bufo including unfertilized eggs. After stage 4 glutathione transferase activity gradually decreased until stage 25 when the minimum was reached. No change in the number of isozymes was noted during development according to isoelectric focusing analysis performed on the cytosolic fractions of selected stages.

Animals↗
PubMed1987

Selenium level and glutathione-dependent enzyme activities in normal and neoplastic human lung tissues.

Selenium, glutathione peroxidase, glutathione reductase and glyoxalase I have been measured in normal and neoplastic human adult lung tissues. Interindividual variations of enzyme activities and selenium content in both tumour and non-tumour tissues were considerable. From the measurements of glutathione peroxidase activity with both hydrogen peroxide and cumene hydroperoxide it was deduced that human tumour and non-tumour lung tissues are devoid of the selenium-independent enzyme. In general, a significant increase in the activity of glutathione peroxidase and glutathione reductase was found in tumour. Glyoxalase I in tumour was as high as in non-tumour samples. Mean selenium concentration tended to be higher in tumour than in non-tumour specimens. When a comparison was made between normal and neoplastic tissue of the same individual, glutathione peroxidase, activity was found to be higher in tumour in 19 cases out of 24 and glutathione reductase in 17 out of 22. In 15 cases out of 18 the selenium levels were found to be higher in tumour. It was concluded that changes in the factors involved in anti-oxidative protection actually occur in human lung tumour tissues.

Adenocarcinoma↗
PubMed1987

Alteration of glutathione transferase isoenzyme concentrations in human renal carcinoma.

Glutathione transferase (GST) activity in the cytosolic fractions of four renal cortex tumors was found to be lower (1.85-3.4 times) than that present in the corresponding non-tumor cytosolic fractions. Glutathione transferase of both tumor and non-tumor kidney was purified by affinity chromatography and separated into five peaks at pH 4.7, 8.0, 8.4, 8.7 and 9.0 by isoelectric focusing. In the chromatogram of tumor tissues, the activity associated with the 'acidic' peak increased significantly, whereas the activities associated with 'basic' peaks all decreased in comparison with the corresponding peaks of non-tumor tissues. The acidic GST of human kidney is immunologically identical to GST pi, confirming that it is a good marker for human tumors.

Aged↗
PubMed1987

Cysteamine oxygenase: possible involvement of superoxide ion in the catalytic mechanism.

The reaction catalyzed by cysteamine oxygenase on cysteamine in the presence of phenazine methosulphate as cofactor like compound is inhibited by nitroblue tetrazolium, a scavenger of superoxide ions. The reaction is not inhibited by superoxide dismutase and allyl alcohol and it is not activated by superoxide ions produced in solution. Nitroblue tetrazolium is reduced by cysteamine or mercaptoethanol and phenazine methosulphate. This reaction is completely inhibited by superoxide dismutase. In the presence of cysteamine oxygenase the reduction with mercaptoethanol is greatly enhanced and it is only partially inhibited by superoxide dismutase. According to these data a reaction mechanism is proposed in which superoxide ions and thiyl radicals are produced at the active site during catalysis.

1-Propanol↗
PubMed1987

Nizatidine in the short-term treatment of duodenal ulcer--an Italian Multicenter Study.

One hundred and seventy three patients suffering from duodenal ulcer, were selected for a double-blind, controlled and randomized parallel multicenter study, with interval endoscopic examinations. This study was undertaken to compare the efficacy and safety of nizatidine administered at a single dose (300 mg "nocte") versus ranitidine (300 mg "nocte") in the treatment of acute duodenal ulcer. One hundred and sixty five patients were found to meet every admission criterion and completed the study (86 on nizatidine and 79 on ranitidine). On admission to the study, both groups were seen to have been correctly selected and epidemiologically well-distributed as to history of duodenal ulcer, previous treatments and pre-study symptoms. The ulcer was considered healed when complete re-epithelialization had occurred in areas of ulcerated mucosa. Healing rates of duodenal ulcer proved to be globally similar in the two groups, both in the 4th week (nizatidine, 78%; ranitidine, 78%) and in the 8th week (nizatidine, 91%; ranitidine, 95%). After four weeks of treatment, 67% of the patients treated with nizatidine no longer had any symptoms, while 87% patients no longer suffered from day pain, and 91% had no nocturnal pain. As a result, intake of antacids quickly decreased during the first four weeks. A similar response was observed in the group receiving ranitidine. After administration at a single dose of 300 mg in the evening, nizatidine proved to be at least as effective and safe as 300 mg of ranitidine administered in the same way, with respect both to ulcer healing and symptom response.

Adult↗
PubMed1987

[Total lactate dehydrogenase content and its isoenzymes in a human platelet subpopulation].

The morphological and functional variability of the platelets is on the way of the study. The morphological platelet transformations corresponding to functional attitudes, need of energetic pattern given by the content, in platelets, of enzymatic patrimony. The results show that the lactic-dehydrogenase and isoenzymes, content in the three studied platelet subpopulations, is different. These significant data, probably show that the platelet subpopulations have a different content in total LDH while show no modification in LDH isoenzymes as show in various functional and energetic different specific point in time.

Adult↗
PubMed1987

The long-term treatment of peptic ulcer after a bleeding episode.

We have studied 51 consecutive patients bleeding from peptic ulcer which was duodenal (D.U.) in 30, gastric in 17 (G.U.), anastomotic in 3 (Billroth 2), and oesophageal in 1 of them. One patient with G.U. was sent for surgery and 2 patients with D.U. died early; the others recovered through medical treatment and the ulcer healed after 6-8 weeks of treatment with ranitidine in 46 out of 48 patients. Subsequently, all the healed patients have been treated with ranitidine (150 mg at bedtime) for 6 months; by this time a new endoscopy showed an erosive antral gastritis in 2 patients with G.U. and 2 recurrences of D.U. Then the patients and their family doctors were invited to choose between the interruption of the treatment and its prolongation. 8 patients with previous G.U. preferred to stop treatment, and up to 1-2 years they did not show any recurrence; the remaining 5 patients carried on the maintenance treatment, and up to one year one of them showed an erosive antral gastritis. 15 patients with previous D.U. stopped the treatment and 5 of them after 1-24 months presented a recurrence with a new haemorrhage; 8 patients chose to continue the treatment and none of them for 6-24 months had recurrence. The limited number of the patients obviously does not allow a sound conclusion, but a trend is clearly seen which favours a prolonged maintenance treatment in patients with D.U. which has bled.

Aged↗
PubMed1986

The transamination of L-cystathionine, L-cystine and related compounds by a bovine kidney transaminase.

An enzyme which actively transaminates L-cystathionine, L-cystine, L-lanthionine and S-aminoethyl-L-cysteine has been purified from bovine kidney. The transaminase appears to be pure up to 90% and probably consists of two subunits of similar molecular mass of about 47 kDa. The enzymatic products arising from the transamination of L-cystathionine and related compounds spontaneously cyclize into ketiminic structures, which are the immediate precursors of unusual imino acids recovered in biological materials. The specificity towards other amino acid and oxo acid acceptors is similar to the specificity exhibited by rat kidney glutamine transaminase. This suggests that the sulfur amino acid transaminations that have been described could be performed by the bovine kidney glutamine transaminase.

Alanine↗
PubMed1986

Alkaline hydrolysis of N-ethylmaleimide allows a rapid assay of glutathione disulfide in biological samples.

The estimation of glutathione disulfide (GSSG) is based on the NADPH-dependent glutathione reductase reaction. A new method has been developed to eliminate the inactivating effect of N-ethylmaleimide (NEM), added to prevent glutathione oxidation, on glutathione reductase. This method takes advantage of instability of NEM in alkaline solutions. The product of NEM hydrolysis, N-ethylmaleamic acid, obtained under accurate pH-controlled conditions, is compatible with a good activity of glutathione reductase which allows total recovery and measurement of GSSG. The method, applied to estimation of GSSG content in human erythrocytes and rat liver, gives results in optimum agreement with values reported in literature. Because of its simple performance and rapidity, the procedure can be considered an improved method in removing NEM and is particularly advantageous when a large number of biological samples must be treated and estimated.

Animals↗
PubMed1986

Glutathione peroxidases and glutathione reductase activities during Bufo bufo development.

Glutathione peroxidases and glutathione reductase activities are expressed from the early stage of Bufo bufo development. Selenium-dependent and selenium-independent glutathione peroxidase activities fluctuated independently. The activity of selenium-independent was found to be higher than that of selenium-dependent glutathione peroxidase through all stages of development. Glutathione reductase activity, after a slight fall from stage 4 to stage 7, constantly increased up to stage 25.

Animals↗
PubMed1986

Selenium independent glutathione peroxidase activity associated with cationic forms of glutathione transferase in human heart.

Glutathione peroxidase activity with both hydrogen peroxide and cumene hydroperoxide was measured in the cytosolic fractions prepared from five human hearts obtained from post-mortem victims. In all the samples the activity with cumene hydroperoxide was higher than that obtained with hydrogen peroxide, suggesting that the selenium-independent glutathione peroxidase could also be present in this tissue. To determine its presence in heart tissue we fractionated the cardiac cytosol fraction on a column of Sephadex G-100 and measured glutathione peroxidase activity with both the substrates. Glutathione transferase activity was measured with 1-chloro-2,4-dinitrobenzene in the fractionated cytosol. The results indicated that a selenium-independent glutathione peroxidase activity was present (about 30% of total activity). Fractionation of the cytosol by gel filtration showed that peroxidase activity co-eluted with glutathione transferase activity. Subsequently the fractions containing glutathione transferase and selenium-independent glutathione peroxidase activity obtained from gel filtration experiments were passed through an affinity column and analyzed by isoelectric focusing. It was found that the selenium-independent glutathione peroxidase copurified with three isoenzymes of glutathione transferase which had a pI of 9.2, 8.9 and 8.6 respectively. In contrast the acidic isoenzymes of glutathione transferase lacked peroxidase activity. It is suggested that the selenium-independent glutathione peroxidase may play an important role in neutralizing oxygen toxicity in heart when the selenium-dependent glutathione peroxidase activity is impaired.

Chromatography, Affinity↗
PubMed1986

Prevention of relapse with various antiulcer drugs.

The relative value of maintenance therapy with cimetidine, ranitidine, pirenzepine, and antacids only (when used for symptomatic relief) has been evaluated in 205 patients with a subsequent follow-up period of 2 years. The patients had a completely healed duodenal ulcer after 8 weeks of treatment and were then randomly allocated to four groups, which were as follows: group 1: 60 patients treated with 400 mg cimetidine at night; group 2: 55 patients treated with 150 mg ranitidine at night; group 3: 50 patients treated with 50 mg pirenzepine at night; and group 4: 40 patients treated only with antacids as needed for symptomatic relief. Endoscopy was repeated after 6, 12, 18, and 24 months of treatment, and whenever symptoms suggested recurrence. Although the number of dropouts was high (27 in group 1, 20 in group 2, 18 in group 3 and 12 in group 4), statistical analysis by the life-table method showed that cimetidine, ranitidine, and pirenzepine had similar therapeutic value. After 1 and 2 years the relapse rate of duodenal ulcer was 17.5% and 43.6% respectively, for cimetidine, 21% and 69.3% for ranitidine, 21.7 and 50.2% for pirenzepine, and 49.8% and 77.7% for antacids. The incidence of erosions was lower in those groups with the higher ulcer relapse rate, a point discussed in the present study.

Adult↗
PubMed1986

Antioxidant systems in tumour cells: the levels of antioxidant enzymes, ferritin, and total iron in a human hepatoma cell line.

The human hepatoma cell line Hep 3B, which has the hepatitis B virus genome, shows over 80% decrease of copper/zinc superoxide dismutase activity, over 90% decrease of manganese superoxide dismutase activity, over 70% decrease of catalase activity, absence of glutathione peroxidase and glutathione S-transferase activities, over 270-fold increase of ferritin content and 25-fold increase of total iron compared to normal autopsy liver. These conditions of low antioxidant enzyme activities and iron overload are those which support the accumulation of oxygen free-radicals and DNA damage commonly considered to be carcinogenic mechanisms.

Animals↗