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Biomedical subjects

G Ricci

Publications and source records attributed to G Ricci.

At least 253 records · Page 14Linked to original sources
PubMed1988

Purification and characterization of a ketimine-reducing enzyme.

An NAD(P)H-dependent reductase able to reduce a new class of cyclic unsaturated compounds named ketimines has been detected and purified 2500-fold from pig kidney. Some molecular and kinetic properties of this enzyme have been determined. The enzymatic reduction proceeds with a classical ping-pong mechanism and some results suggest that the true substrate has the ketiminic structure and is in equilibrium with the enaminic and keto-open forms. As previously described, ketimines arise from the deamination of a number of sulfur-containing amino acids, i.e. L-cystathionine, L-lanthionine and S-aminoethyl-L-cysteine, catalyzed by a widespread mammalian transaminase. The enzymatic reduction products of ketimines have been identified as cyclothionine, 1,4-thiomorpholine 3,5-dicarboxylic acid and 1,4-thiomorpholine 3-carboxylic acid. Some of these compounds have been detected in mammals, thus suggesting a possible role of this enzyme in their biosynthesis.

Amino Acids, Sulfur↗
PubMed1988

Serum thiocyanate levels as an objective measure of smoking habits in epidemiological studies.

The relationship between smoking habits and plasma thiocyanate levels has been evaluated in four adult samples of the general population containing men and women aged 20-84 and in a sample of 11-year-old non-smoking children of both sexes, for a total of 7577 individuals. Mean levels of plasma thiocyanate was found be approximately 20 mumol/l in children, 30 mumol/l in non-smoking adults and increasingly higher in smoking adults. The slopes of the regression equations of thiocyanate on cigarettes smoked per day range from 3.041 to 5.740, with correlation coefficients of from 0.638 to 0.809. In another occupational sample of 2802 men aged 46 to 65, where the correlation coefficient (between cigarette consumption and thiocyanate) was only 0.49, plasma thiocyanate was a better predictor of 4 year fatal events than cigarette consumption, 4 other covariates being considered in the same multivariate model.

Adult↗
PubMed1988

Life-threatening hyponatremia caused by vinblastine.

Some days after the administration of a third bolus of ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) a patient affected by immunoblastic lymphoma underwent a neurotoxic crisis. The episode lasted 1 week and was followed by a dramatic fall in plasma sodium (104 mEq I-1), associated with a proportionally lesser decrease in plasma chloride and phosphate. Despite the lowest plasma osmolality, detectable levels of circulating ADH were present. After 36 h the hyponatremic episode improved after the infusion of hypertonic sodium chloride. Nevertheless the patient lapsed into a hypotonic coma. The urinary concentrations of the main tubular enzymes (gamma-glutamyltranspeptidase, N-acetyl-glucosaminidase, alpha-glucosidase) proved very high and successively decreased slowly. The most likely cause of such hyponatremic episode is vinblastine. The drug acted through: (a) an already known inappropriate release of ADH, and (b) a hitherto unreported tubular lesion, which impaired the reabsorption of sodium and other coupled solutes.

Adult↗
PubMed1988

Different kalemia in abdominal trauma.

Unlike previous reports, in 123 patients with abdominal injury or surgery significant and persistent hypokalemia was observed only after traumatic or surgical injuries of the liver. On the contrary, in all other extrahepatic abdominal trauma or operations kalemia was normal. This discrepancy may be related to the much greater abundance, in comparison with other abdominal organs, of adrenergic endings present in the liver. Trauma to or surgery of the liver stimulates such fibers, which locally release proportionally large amounts of norepinephrine. The consequent stimulation of beta-adrenergic receptors enhances the transfer of potassium from the blood into the cells, even if the affinity of norepinephrine for such receptors is less than that of epinephrine. The frequent finding of kaliuria at the upper normal levels may suggest an accessory role of aldosterone in causing and maintaining this hypokalemia.

Abdominal Injuries↗
PubMed1988

Effects of exercise on haematologic parameters, serum iron, serum ferritin, red cell 2,3-diphosphoglycerate and creatine contents, and serum erythropoietin in long-distance runners during basal training.

We studied 18 well-trained male long-distance runners during the basal training. Haematologic parameters, serum iron and ferritin, red cell 2,3-diphosphoglycerate (2,3-DPG) and creatine contents, serum erythropoietin were investigated before and after the daily training and were compared with a group of healthy untrained controls. Red blood cell parameters did not change with the training, even though they were significantly lower than in controls. However, a true anaemic state cannot be suggested because the haemoglobin values fell into the lower limit of the normal range, even before the exercise. A slight but significant increase of neutrophils was found after the exercise, while no alteration of platelet count was observed. Serum iron and ferritin ranged normally. No increase of red cell 2,3-DPG was observed after the exercise, but it was significantly higher than in controls. After the exercise red creatinine was slightly increased. The athletes' erythropoietin was higher than that of controls, and showed a further increase after the training.

2,3-Diphosphoglycerate↗
PubMed1988

A long-term study on the use of evening primrose oil (Efamol) in atopic children.

The effect of essential fatty acids on atopic eczema is controversial. Some workers have reported that patients with atopic eczema improved following oral treatment with evening primrose oil (an oil with a high concentration of gamma-linolenic acid), but others have disputed this. This study was designed to look at the effect of evening primrose oil as a long-term oral supplementation for children with atopic eczema. Treated children dramatically improved their clinical condition after 4 weeks of therapy, and this improvement was maintained during the whole period of treatment (20 weeks). At the same time, modifications in plasma, neutrophil and lymphocyte fatty acid composition were detected.

Child, Preschool↗
PubMed1988

Evening primrose oil (Efamol) in the treatment of children with atopic eczema.

It has been reported that essential fatty acid levels may be low and that there may be reduced levels of delta-6-desaturase metabolites of linoleic acid in patients with atopic eczema. Good therapeutic results have been reported on the use of evening primrose oil (Efamol) in adults but not in children. Efamol contains gamma-linolenic acid, the delta-6-desaturase metabolite of linoleic acid. The authors have studied 24 children with atopic eczema: 12 of them were treated with a higher dose of evening primrose oil than in previous studies and 12 with placebo olive oil. The clinical status and plasma, neutrophil and lymphocyte fatty acid composition in these children have been evaluated. After 4 weeks the eczema of essential fatty acid-treated children significantly improved in comparison with that of placebo-treated children (p less than 0.01). There were significant changes in plasma fatty acid composition between the basal values and the end of active treatment, and between the placebo and actively treated children. Neutrophil and lymphocyte fatty acid composition did not seem to be related to disease activity.

Child, Preschool↗
PubMed1988

Creatine and membrane sialic acid contents of erythrocytes in patients with heart valve prostheses.

The red cell damage induced by heart valve prostheses was investigated in 2 groups of patients with different heart valve replacements (mechanical or biological devices) by the determination of the creatine and membrane sialic acid contents in the erythrocytes. Red cell creatine did not increase, whereas sialic acid was lowered in both groups of patients, when compared with healthy controls. These findings were briefly discussed.

Creatine↗
PubMed1988

Outpatient hysteroscopy in the diagnosis of neoplastic and preneoplastic lesions of the endometrium.

The results of a study performed on a case series of 250 women treated in our out-patient department for abnormal uterine bleeding are reported. Half of these patients (125) were 45 years of age or over and therefore at risk of adenocarcinoma or endometrial hyperplasia while the other half were under 45 years of age. All the patients were submitted to hysteroscopic examination as out-patients (no important side-effects occurred), together with cytologic and/or histological examination of the endometrium. This procedure revealed no disease in 59 cases (23.6%) and the presence of one or more benign conditions in 188 patients (75.2%) (inflammation, polyposis, myomatosis, endocervical or uterine adenomiosis, endometrial hyperplasias, dysfunctional patterns, intrauterine foreign bodies). Endometrial adenocarcinoma was diagnosed in 3 patients (1.2%). The discovery of 3 cases (1.2%) of adenocarcinomas and 62 cases (24.8%) of endometrial hyperplasias (58 simple glandular hyperplasia, 3 cystic-glandular hyperplasias and 1 polypoid hyperplasia) emphasive the reliability of hysteroscopy in the diagnosis of endometrial neoplasias and their precursors.

Ambulatory Care↗
PubMed1987

[Excess mineralocorticoid syndrome secondary to nasal sprays containing 9 alpha-fluoroprednisolone].

Two patients with signs of hypermineralcorticism and suppressed plasma aldosterone levels are reported. For both patients the use of a nasal spray containing 9 alpha-fluoroprednisolone had been ascertained, the withdrawal of which was followed by the normalization of the clinical picture as well as by the normal reactivity of the renin-aldosterone system. The endocrine studies excluded the presence of enzymatic defects or the hypersecretion of minor mineralocorticoids. The tests with angiotensin II and ACTH did not result in an increase in aldosterone, which instead increased in a significant way after metoclopramide, even with still suppressed basal values. Since the PRA was normal at the time of the metoclopramide test, a persisting inhibition of the factors directly controlling aldosterone secretion by 9 alpha-fluoroprednisolone could be possibly envisaged. An interesting findings was the onset of severe hypokalemia, conditioning rhabdomyolysis with myoglobinuria in patient 1, after a treatment of few weeks only. Since the factitious use of mineral corticoids is not taken into account, the need of an accurate collection of case history in the differential diagnosis of hyporeninemic hypoaldosteronism with hypokalemia is stressed.

Aldosterone↗
PubMed1987

Ketimine rings: useful detectors of enzymatic activities in solution and on polyacrylamide gel. Detection of L-amino acid oxidase, glutamine transaminase, pantetheinase, and acylase I.

A simple procedure has been developed for the detection of L-amino acid oxidase, glutamine transaminase, pantetheinase, and acylase I in solution and on polyacrylamide gels. The method is based on the strong absorbance at 296 nm of some ketimine rings which can be directly produced by the enzymatic reaction or formed by the reaction of the enzymatic product with 3-bromopyruvate. The procedure allows one to visualize up to about 1-10 mU of enzyme.

Amidohydrolases↗
PubMed1987

Hexahydro-1,4-thiazepine-3,5-dicarboxylic acid and thiomorpholine-3,5-dicarboxylic acid are present in normal human urine.

Hexahydro-1,4-thiazepine-3,5-dicarboxylic acid and thiomorpholine-3,5-dicarboxylic acid, simply referred to as cyclothionine and TMDA, respectively, are two cyclic sulfur-containing imino acids detected in bovine brain. Human urine has been investigated to establish the occurrence of these imino acids as common constituents under normal conditions. The morning urine of healthy subjects has been analyzed for enrichment of these compounds by using an ion-exchange procedure. Gas/liquid chromatography of the final extracts revealed the presence of peaks coeluting with authentic cyclothionine and TMDA. The latter compound eluted very close to an unknown sulfur-containing compound. A resolved peak of TMDA has been obtained by high-performance liquid chromatography of the final extracts derivatized with phenylisothiocyanate. Selected ion monitoring with multiple-ion detection applied to the compounds separated by gas chromatography revealed the presence of the respective molecular ions and of the decarboxylated fragments, thus confirming the identification of cyclothionine and TMDA in human urine.

Adult↗
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↗