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Biomedical subjects

G Ricci

Publications and source records attributed to G Ricci.

At least 235 records · Page 13Linked to original sources
PubMed1990

Detection of cystathionine ketimine in bovine cerebellum.

A new sulfur-containing cyclic imino acid, cystathionine ketimine, has been detected in bovine cerebellum by gas chromatography, gas chromatography-mass spectrometry, and high pressure liquid chromatography procedures. Gas chromatography and gas-mass analyses are based on derivatization of endogenous cystathionine ketimine with diazomethane after a simple enrichment procedure. The high pressure liquid chromatography procedure takes advantage of the selective absorbance at 380 nm of the phenyl isothiocyanate-ketimine interaction product. The concentration of this new sulfur imino acid found in a pool of four bovine cerebella is approximately 0.5 nmol/g.

Animals↗
PubMed1990

Atopic background of a recurrent papular eruption of childhood (frictional lichenoid eruption).

Thirty-five children affected by a recurrent summer and spring papular eruption on the elbows, knees, and backs of the hands were examined retrospectively in order to evaluate the frequency of atopy. It was found that 45.7% were suffering from atopic diseases (atopic eczema, allergic rhinitis, asthma). This high proportion confirms the fact that an underlying atopy may predispose to the occurrence of this dermatosis.

Child↗
PubMed1990

Papular and papulovesicular acrolocated eruptions and viral infections.

Twenty-six children with a symmetric papular or papulovesicular acrolocated eruption were studied to evaluate a possible link with viral infection. A history of a recent immunization was present in four patients, two of whom had a polio vaccine virus isolated from their stool samples. There was serologic evidence of a recent Epstein-Barr virus infection in one patient, adenovirus infection in another, a concurrent Epstein-Barr virus and adenovirus infection in a third, and cytomegalovirus infection in a fourth. Viral cultures were positive in two patients for adenovirus and in two others for rotavirus. Although some of the virologic findings could have been coincidental, this study confirms that multiple viral infections can be related to most papular and papulovesicular acrolocated eruptions of childhood. Virologic investigations in the earlier phases of the eruption are recommended to identify the etiologic factors of these lesions.

Adenoviridae Infections↗
PubMed1990

Serum lipoprotein pattern variations in dementia and ischemic stroke.

Blood levels of triglycerides, total cholesterol, isolated lipoprotein fractions (VLDL-LDL- and HDL-cholesterol) and apoproteins (Apo-A1 and Apo-B) were examined in multi-infarct dementia, senile dementia of the Alzheimer type, ischemic stroke associated with carotid atherosclerosis and in control subjects. Forty patients divided into 10 consecutive patients for each group were studied. Alzheimer patients showed mean total cholesterol and Apo-B values significantly higher than control subjects. Apo-B was significantly higher in stroke patients than in controls. The mean lowest HDL-cholesterol (HDL-c) value was observed in stroke patients. No significant differences in mean HDL-c levels were found between patients with multi-infarct and Alzheimer dementia.

Aged↗
PubMed1989

Identification of 1,4-thiomorpholine-3-carboxylic acid (TMA) in normal human urine.

The sulfur-containing cyclic imino acid 1,4-thiomorpholine-3-carboxylic acid (TMA) has been identified in normal human urine. After the enrichment procedure with ion-exchange chromatography, the urine extracts were reacted with diazomethane. Gas-liquid chromatography revealed the presence of two peaks with the same retention times exhibited by authentic TMA after the same derivatization. The two compounds have been identified by mass-spectrometry as the monomethylated and dimethylated derivatives of TMA. This result represents the first indication of the occurrence of TMA in a mammalian sample.

Gas Chromatography-Mass Spectrometry↗
PubMed1989

Nonequivalence of the two subunits of horse erythrocyte glutathione transferase in their reaction with sulfhydryl reagents.

Glutathione transferase (EC 2.5.1.18) from horse erythrocytes has been purified and some molecular and kinetic properties have been investigated. It appears to be a dimeric protein composed of subunits of about 23 kDa, indistinguishable either in sodium dodecyl sulfate or in urea electrophoresis. Amino acid composition, substrate specificities, sensitivity to inhibitors, CD spectra, and immunological studies provide evidence that the horse enzyme is related to the pi class transferases. This enzyme has only two reactive thiol groups/dimer whose integrity appears to be essential for the activity. A peculiar feature of these protein thiol groups is that they react nonidentically with a number of thiol blocking reagents, i.e. iodacetamide, bromopyruvate, N-ethylmaleimide, and 1-chloro-2,4-dinitrobenzene. Also many disulfides react with one thiol group 5- to 10-fold more rapidly than with the other. The two mixed disulfides so formed also have different rates of reactivation by dithiothreitol. All the structural and kinetic data reported in this paper indicate a nonsymmetrical association of two identical subunits, or alternatively heterodimeric structure with subunits of very similar charge and size.

Amino Acids↗
PubMed1989

Electrophoretic and immunological analysis of glutathione transferase isoenzymes of human kidney carcinoma.

By sequential use of GSH-affinity chromatography and chromatofocusing, the isoenzymes of glutathione transferase from tumor and non-tumor kidney tissues have been purified and their properties compared. On the basis of electrophoretic mobilities on SDS/polyacrylamide gel, substrate specificities toward the diagnostic substrates cumene hydroperoxide and ethacrynic acid and immunoreactivity with antisera raised against alpha, mu and pi class glutathione transferases, it was found that most of the isoenzymes purified from both tumor and non-tumor kidney can be identified as members of either alpha or pi classes. All the samples investigated lacked mu class glutathione transferase. In addition, we could identify in tumor samples two transferases GST-7.6 and GST-5.8/5.9 which on the basis of immunological properties cannot be related to any of the members of the three major classes of glutathione transferases. The latter do not appear to have corresponding forms in non-tumor tissues. It was suggested that specific transferases can be selectively expressed by tumor kidney carcinoma.

Carcinoma, Renal Cell↗
PubMed1989

Detection of 2H-1,4-thiazine-5,6-dihydro-3,5-dicarboxylic acid (lanthionine ketimine) in the bovine brain by a fluorometric assay.

A new sulfur imino acid, 2H-1,4-thiazine-5,6-dihydro-3,5-dicarboxylic acid (lanthionine ketimine), has been detected in the bovine brain by means of fluorometric and HPLC procedures. The fluorometric assay is based on the fluorescent property of the copper-ketimine interaction product at pH 11.5. Other ketimines do not fluoresce in these conditions. The fluorophore exhibits an excitation maximum at 353 nm and an emission at 462 nm and is stable for at least 24 h. In the test conditions the fluorescence is proportional to the ketimine concentration from 1 to 200 microM. Detection of endogenous lanthionine ketimine has been performed after a simple enrichment procedure (brain deproteinization and extraction with diethyl ether) which minimizes degradative by-reactions of the unstable ketimine. The concentration of this new sulfur imino acid in the brain ranges from 0.5 to 1 nmol/g in three different samples. Identification and quantitations were confirmed by an HPLC procedure which takes advantage of the selective absorption at 380 nm of the phenylisothiocyanate-ketimine adduct. The identification of lanthionine ketimine in nervous tissues may have important metabolic and physiological implications.

Amino Acids, Sulfur↗
PubMed1989

High density lipoprotein cholesterol distribution and predictive power in some Italian populations studies.

Nine Italian population samples, for a total of 12,365 males and 8,043 females aged 11 to 84, were examined. The age and sex distribution of HDL-cholesterol levels were calculated for studying its relationship with major cardiovascular risk factors, and for estimating its predictive power on coronary events and on all causes of mortality. Mean values of HDL-cholesterol in the pool of the samples ranged, according to different age groups, from 46.4 to 56.8 mg/dl in males and from 53.7 to 55.8 mg/dl in females. The linear correlation coefficients between HDL-cholesterol and 10 risk factors did not show high levels except those with triglycerides in men aged 20-34 (-0.33) and 35-64 (-0.34). Using the multiple linear regression model the levels of HDL-cholesterol were estimated as a function of the 10 risk factors solving 4 equations (for males, females and for two age groups, 20-34 and 35-64). The factors showing significant coefficients were body mass index (negative), triglycerides (negative), cigarette smoking (negative), alcohol consumption (positive), physical activity (positive), and non-HDL-cholesterol (negative). The Cox model was used for the prediction of coronary death and all causes of death and the logistic function for the prediction of coronary incidence in two of the studies on men aged 46-65 (6 year follow-up) and aged 60-79 (5 year follow-up), and including 5 other factors as possible confounders. Only the univariate prediction of coronary deaths in one study (men aged 46-65) provided a significant coefficient for HDL-cholesterol (t = -2.7624).

Adolescent↗
PubMed1989

Inter and intra-observer variation in ultrasonographic detection of gallstones: the Multicenter Italian study on epidemiology of cholelithiasis (M.I.COL.).

Inter and intra-observer agreement in classifying the presence of gallstones by ultrasonographic images according to established criteria was studied. A film recording of 50 routine ultrasonographic examinations of the gallbladder was read by each of the 46 observers who participated in the Multicenter Italian Study on Epidemiology of Cholelithiasis (M.I.COL.). The overall Kappa score for inter-observer agreement was 0.649, while intra-observer agreement was "good" or "excellent" (Kappa scores greater than 0.60) in 75% of the observers. No statistical difference for inter-observer agreement between "novices" and "expert" echographers was found in the overall Kappa statistic or in category-specific Kappa scores (gallstone, no gallstone, doubtful and inconclusive examinations) The present study suggests that the development of explicit criteria by a group of trained echographers does not eliminate inter- and intra-observer disagreement in categorizing subjects for gallbladder stones.

Cholelithiasis↗
PubMed1989

Immunological parameters in Darier's disease.

Patients with Darier's disease have frequently been observed to develop severe bacterial and viral infections. Previous studies have indicated some derangement in the immune system, even though no consistent or specific abnormality has yet been demonstrated. We performed the results of immunologic studies in 10 patients with Darier's disease. In each patient humoral immunity and cell-mediated immunity (in vivo and in vitro) were evaluated and leukocyte chemotactic function was assayed. Humoral immunity was normal; as regards clusters of differentiation (CD), a slight increase in CD4 lymphocyte subpopulations was observed in 7 patients and of CD4/CD8 ratio in 1 case. The lymphocyte responses to phytohemagglutinin and concanavalin A were normal, whereas the response to pokeweed mitogen was decreased slightly, but not significantly. Normal random and chemotactic mobility was found in all the patients except one. The data obtained do not show important immunological alterations. Our patients did not have a high propensity to develop severe infections and this may explain the absence of significant immunological derangement. Our data confirm that no immunological derangement is associated with Darier's disease.

Adult↗
PubMed1989

Photooxidation of hypotaurine to taurine in the presence of flavins.

Irradiation of organic sulfinates such as hypotaurine and cysteine sulfinic acid in the presence of catalytic amounts of flavins led to the oxidation of its sulfinic groups (-SO2H) to the corresponding sulfonates. The process of hypotaurine oxidation in the presence of riboflavin, followed by absorbance decrease at 220 nm and by ion-exchange chromatography, showed a pseudo-first-order kinetics at pH 6.0. The k value depended linearly on flavin concentrations. The reaction rate was higher at acidic pH. Although the reaction rate was not affected by the addition of superoxide dismutase or catalase, superoxide ions were supposed to be by-products of the reaction. The effectiveness of allyl alcohol as a scavenger pointed to a free-radical mechanism of the reaction. We propose a new reaction mechanism involving sulfinic radicals on this photochemical reaction.

Amino Acids↗
PubMed1989

[Submaxillary gland excisions: a retrospective investigation].

Swellings of the submaxillary region are very frequent in otorhinolaryngology clinical practice. The authors of this study analyzed 106 cases of submaxillary gland excision under their observation, emphasizing their epidemiological, clinical and anatomopathological aspects which could be useful during the diagnostic and therapeutic phase of the submaxillary gland affections. They also made a comparison with the data already published on the same subject.

Adult↗
PubMed1988

Bovine brain ketimine reductase.

We report the purification from bovine brain of an NAD(P)H-dependent reductase which actively reduces a new class of cyclic unsaturated compounds, named ketimines. Ketimines arise from the transamination of some sulphur-containing amino acids, such as L-cystathionine, S-aminoethyl-L-cysteine and L-lanthionine. The enzyme also reduces delta 1-piperidine 2-carboxylate, the carbon analog of aminoethylcysteine ketimine. Some kinetic and molecular properties of this enzyme have been determined. Subcellular localization and regional brain distribution have also been studied. The ketimine reductase activity was found to be associated with the soluble fraction, and was located prevalently in the cerebellum and cerebral cortices. Cyclothionine and 1,4-thiomorpholine-3,5-dicarboxylic acid, the enzymatic reduction products of cystathionine ketimine and lanthionine ketimine, respectively, have been detected in bovine brain, thus suggesting a role of this enzyme in their biosynthesis.

Animals↗