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Biomedical subjects

V Carbone

Publications and source records attributed to V Carbone.

At least 37 records · Page 2Linked to original sources
PubMed2000

The mutation associated with Hb Peterborough [beta111(G13)Val-->Phe] originated from Southern Italy.

Hb Peterborough [beta111(G13)Val-->Phe], an unstable hemoglobin variant with low oxygen affinity, was first described in two patients of Italian origin. This paper reports the first observation of this variant in Campania, Southern Italy, in two unrelated patients suffering from mild anemia. The variant was separated from Hb A by cation exchange chromatography on a high performance liquid chromatographic system with an automated procedure that might be useful for diagnostic purposes. The amino acid replacement, Val-Phe at [beta111, was assessed by tandem electrospray mass spectrometry analysis, and the corresponding DNA mutation was established as G-->T at the first position of codon 111 (GTC-TTC) by polymerase chain reaction amplification techniques. A family study showed that the two original carriers of Hb Peterborough were members of the same family as the proband examined in this study. This finding, and the presence of a second unrelated family carrying Hb Peterborough in Campania, strongly suggests that the DNA mutation associated with this variant originated in Southern Italy.

Adult↗
PubMed1999

Ornithine and glutamate decarboxylases catalyse an oxidative deamination of their alpha-methyl substrates.

Ornithine decarboxylase (ODC) from Lactobacillus 30a catalyses the cleavage of alpha-methylornithine into ammonia and 2-methyl-1-pyrroline; glutamate decarboxylase (GAD) from Escherichia coli catalyses the cleavage of alpha-methylglutamate into ammonia and laevulinic acid. In our analyses, 2-methyl-1-pyrroline and laevulinic acid were identified by HPLC and mass spectroscopic analysis, and ammonia was identified by means of glutamate dehydrogenase. Molecular oxygen was consumed during these reactions in a 1:2 molar ratio with respect to the products. The catalytic efficiencies (k(cat)/K(m)) of the reactions catalysed by ODC and GAD were determined as 12500 and 9163 M(-1).min(-1) respectively. When the reactions were performed under anaerobic conditions, no ammonia, 2-methyl-1-pyrroline or laevulinic acid was produced to a significant extent. The formation of ammonia and O(2) consumption (in a 1:2 molar ratio with respect to ammonia) were also detected during the reaction of ODC and GAD with putrescine and gamma-aminobutyrate respectively. Taken together, these findings clearly indicate that ODC and GAD catalyse an oxidative deamination of their decarboxylation products, a reaction similar to that catalysed by dopa decarboxylase (DDC) with alpha-methyldopa [Bertoldi, Dominici, Moore, Maras and Borri Voltattorni (1998) Biochemistry 37, 6552-6561]. Furthermore, this reaction was accompanied by a decarboxylation-dependent transamination occurring for GAD, DDC and ODC with a frequency of approx. 0.24%, 1% and 9% respectively compared with that of oxidative deamination.

Ammonia↗
PubMed1999

Photopolarimetric characterization of the transition between two turbulent states in a nematic liquid crystal film.

This work was aimed at the photopolarimetric characterization of the transition between two dynamic scattering modes that take place in a planarly aligned nematic liquid crystal sample, under the effect of an external low-frequency electric field. The time evolution of the degree of polarization and the behavior of the radiation entropy of the transmitted light allow us to interpret the transition between two turbulent states, or dynamic scattering modes, as a decay from a two-dimensional (2D) to a (3D) turbulence.

Journal Article↗
PubMed1999

Hb Rainier [beta145(HC2)Tyr-->Cys] in Italy. Characterization of the amino acid substitution and the DNA mutation.

A high oxygen affinity hemoglobin variant was identified in a 53-year-old male patient from Napoli (Italy), suffering from pulmonary thromboembolism and polycythemia. A detailed structural characterization of the variant hemoglobin was carried out, both at the protein and DNA levels, by a combination of DNA sequencing and allele-specific amplification techniques with mass spectrometric procedures. The amino acid substitution was found to be Tyr-->Cys, and the corresponding DNA mutation was identified as A-->G at the second position of codon 145 of the beta chain. These variations indicated the presence of Hb Rainier. Haplotype analysis of DNA polymorphisms showed that the beta-globin gene from Hb Rainier was associated with haplotype II. Moreover, structural analyses provided direct identification of an intramolecular disulphide bridge joining the newly inserted beta145Cys with beta93Cys. This is the first report of the occurrence of Hb Rainier in Italy.

Adolescent↗
PubMed1998

Lipocalins of boar salivary glands binding odours and pheromones.

Large amounts of an odorant-binding protein have been isolated from submaxillary glands of mature male pig. This polypeptide molecule is sex-specific, being absent in females. On electrophoretic gels under denaturing conditions it migrated as a broad band with an apparent molecular mass of around 20 kDa. Electrospray mass spectrometry revealed the presence of three main components, whose mass differences are not interpretable as result of any common post-translational modifications, indicating the presence of distinct polypeptide chains. N-terminal Edman degradation yielded a single sequence of 29 amino acids. It includes the lipocalin signature (-G-X-W-) and shows clear homology with a subclass of odorant-binding proteins present in mouse saliva, nasal mucus and urine. The purified protein still retained small ligands tightly bound; among them 5alpha-androst-16-en-3-one and 5alpha-androst-16-en-3alpha-ol, both known sex pheromones for the pig, were identified. The protein also binds 2-isobutyl-3-methoxypyrazine, a good ligand for most odorant-binding proteins, with a dissociation constant of 5 microM.

Amino Acid Sequence↗
PubMed1998

Palomar project: predicting school renouncing dropouts, using the artificial neural networks as a support for educational policy decisions.

The "Palomar" project confronts two problem situations that are partly independent and partly connected to the Italian schooling system: unstable participation in school such as drop out and educational guidance. Our concern is that of a set of phenomena which consists of ceasing compulsory education, repetition of a year at school, school "drop outs", irregular compulsory attendance and delays in the course of studies. The "Palomar" project is designed to offer educators and administrators who want to effectively intervene with these complex problems to furnish school guidance services as an instrument able to: 1. Predict: creating a system able to predict in advance (not in a "cause-effect" way but as an approximation): a) which students are at "risk" for school destabilization or failure; b) what are the prototypical characteristics of these students; c) which students among those studied are more likely to "destabilize" or fail in school; in which course of study does each student have the greatest chance of success; d) which, among the variables studied and appropriately weighted for each student, will predict the successful grade, analyzed for each possible course of studies. 2. Optimize: selecting and focusing on a student on the basis of the information given. It is possible: a) to point out which personal factors (relational, familial, student, disciplinary, economical) need to be reinforced in order to improve the school performances of each selected student, both to prevent or limit "dropping out" desertion or failure and to raise the performances in the chosen school course as much as possible; b) on the basis of what was mentioned above, to simulate the possible support measures to increase the efficacy of the considered intervention; c) to choose for each student the appropriate intervention strategy capable of obtaining the maximum result and the maximum efficacy in the given conditions. 3. Verify: when the strategy of intervention has been decided and we proceed with its implementation, it is possible to periodically verify ("follow-up"), through subsequent administration of the form, the outcome variations elapsed in the prediction of school success or failure. This makes it possible to verify in itinere the efficacy of the interventions carried out and, if necessary, to create variations and adjustments. 4. Produce scenarios: the application field of the Prediction System with Artificial Neural Networks can also be one of a group of students, of one or more organized units (for example a class, a school, or a group of schools). In this case the Prediction System ANN using the program SCHEMA (Buscema, 1996b) is able to: a) determine intervention strategies in order to optimize and to produce the maximum results of a group of students as the one of a class; b) optimize the formative route of a whole institute in order to prevent or limit the need for school guidance.

Adolescent↗
PubMed1997

Effect of low density lipoprotein fatty acid composition on copper-induced peroxidation: 1H-nuclear magnetic resonance analysis.

Oxidation of low density lipoprotein (LDL) has been implicated in atherogenesis. An increased content of oleic acid in LDL and the substitution of monounsaturated for polyunsaturated fatty acids in the diet reduce LDL oxidation. With 1H-NMR analysis, all LDL modifications, including the production of copper-induced aldehyde products, can be evaluated simultaneously. The aim of the present study was to investigate whether the fatty acid composition of LDL affected the NMR evaluation of aldehyde compounds. The LDL of the samples utilized were rich in oleic fatty acid (26.9%). After 48 h of exposure to copper sulfate, the mean production of malonyldialdehyde (MDA) by LDL was 31.2 nmol/mg of protein. Moreover, in the present study NMR did not reveal large amounts of peroxidative compounds since the nanomolar amounts of MDA produced after exposure to copper sulfate could not be detected. This study also demonstrated that the fatty acid composition (i.e. the oleic:linoleic acid ratio) must be taken into account in the evaluation of LDL peroxidation by NMR. In particular, a high concentration of oleic acid may limit the formation of large amounts of peroxidative compounds generated after exposure to the oxidant copper sulfate.

Adult↗
PubMed1997

In vitro reactivity of the antineoplastic drug carmustin and acrolein with model peptides.

The in vitro interaction of the antineoplastic drug 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) and acrolein with model peptides has been investigated in order to provide a detailed description of their electrophilic reactivity towards biological macromolecules. Following incubation with these substances, the modified species were separated by HPLC and identified by fast atom bombardment mass spectrometry, whereas the reactive amino acids within the peptide structure were assigned by tandem mass spectrometry. Incubation with BCNU led essentially to the formation of an N-terminal carbamoyl derivative that slowly decomposed to form three isomeric structures and a very minor ethylated adduct. Alkylation with acrolein gave rise to a mixture of different adducts due to the reaction of both the double bond and the carbonyl group. Two species containing intramolecular cross-links were also observed. These results constitute the prerequisite for in vitro and in vivo studies on the modification of haemoglobin in patients following treatment with antineoplastic drugs.

Acrolein↗
PubMed1997

Enhancement of calcyclin gene RNA expression in squamous cell carcinoma of the oral mucosa, but not in benign lesions.

Oral cancer is a neoplasm with some known causes. Proliferation genes are significant among its few pathogenetic and prognostic factors. Calcyclin is a cell-cycle-related gene, the function of which is still unclear. Its expression and that of Haras and histone-H3 have been investigated in an assessment of their pathogenetic role in squamous cell carcinoma. RNA extracted from the pathological and normal mucosa of patients with squamous cell carcinoma (SCC) and benign lesions was reverse transcribed and amplified by the polymerase chain reaction (PCR). The expression of all three genes in the pathological mucosa was enhanced in SCC only. This suggests that they may be involved in its pathogenesis and provides another parameter for the differentiation of malignant and benign lesions.

Adult↗
PubMed1997

Compound heterozygosity for Hb Lepore-Boston and Hb Neapolis (Dhonburi) [beta 126(H4)Val-->Gly] in a patient from Naples, Italy.

The simultaneous presence of two hemoglobin variants has been detected in a 14-month-old patient affected by thalassemia intermedia. The two variants were characterized by a combination of allele-specific amplification methods and mass spectrometric procedures carried out on isolated globins. These were identified as Hb Lepore-Boston and Hb Neapolis (also known as Hb Dhonburi) or beta 126 (H4)Val-->Gly. Hb Lepore-Boston is the most common hybrid variant detected in Campania and several cases of Hb Neapolis which causes a mild hypochromic microcytic anemia have been identified in this region in the last few years. This is the first report of a double heterozygosity involving Hb Lepore-Boston and Hb Neapolis.

Follow-Up Studies↗
PubMed1997

[Rokitamycin in odontostomatology. Controlled study of doses].

BACKGROUND: Rokitamycin is a semisynthetic macrolide with a lactonic ring with 16 atoms, showing anti-bacterial action at concentrations near to MIC. A controlled clinical study is carried out, in parallel groups, whose aim was to assess the therapeutic action and safety of two dosage schemes of rokitamycin, in the short term treatment (5 days) of acute infective processes of odontostomatological origin. METHODS: Twenty patients (14 males, 6 females) were recruited for the trial, suffering from alveolitis, abscess, phlegmon, sialadenitis and suppurating cysts. The patients were divided in a randomized fashion into two groups: 10 patients were treated orally with 800 mg/day and 10 with 1200 mg/day. Rokitamycin was supplied in 400 mg tablets. RESULTS: The 5 days of treatment with rokitamycin determined the complete resolution of the infective process, with eradication of the germs originally isolated, all belonging to the Streptococcus genus. Clinical efficacy was evident by the third day of treatment, with a prompt improvement of symptoms (functional limitation, pain, tumefaction) and the return of body temperature to within normal limits, in a totally superimposable fashion between the two groups. Safety was excellent with both doses, with no side effects observed. CONCLUSIONS: The results of the study show that treatment with rokitamycin in the short term, at the usual dosage of 800 mg/day, is a valid therapeutic scheme in infective processes in odontostomatology.

Adolescent↗
PubMed1996

Structural characterization by mass spectrometry of hemoglobin adducts formed after in vivo exposure to methyl bromide.

A mass spectrometric procedure is described for the structural study of the adducts formed in human hemoglobin by in vitro exposure of erythrocytes to the alkylating agent methyl bromide using different protein to reagent ratios. Peptide mapping by HPLC and tandem mass spectrometry allowed location of methylated amino acids within the protein sequence. A prominent reactivity of several nucleophilic side chains in human hemoglobin subunits was observed, which was modulated by the concentration of the alkylating agent. Cysteine residues, the main reactive sites, were fully methylated in hemoglobin exposed to a 10-fold excess of methyl bromide, differently from other residues, including histidines, showing a heterogeneous pattern of methylation that was largely directed by their environment. No evidence of methylation was found at the heme proximal histidines beta92 and alpha87. A more selective methylation was obtained when the ratio methyl bromide: hemoglobin was lowered to about 1:1. In this last case only specific residues were reactive. Among them, the N-terminal amino group of both alpha- and beta-globins, cysteine 104 in the alpha-chain and cysteine 93 (not cysteine 112) in the beta-chain, indicating a different accessibility to reaction of the sulfhydryl groups on the protein chain. Thus hemoglobin side chains are selectively modified and the degree of modification at each site is a function of the position of the single amino acid residue within the protein quaternary structure, raising the possibility that alterations of structure and functional properties of human hemoglobin following exposure to alkylating agents may be mediated through such covalent protein modifications. The results obtained demonstrate the usefulness of the analytical approach for the characterization of hemoglobin adducts with methyl bromide or similar compounds, which can constitute the basis for biomonitoring of human exposure.

Alkylation↗
PubMed1995

Mass spectrometric analysis of haemoglobin adducts formed by methyl bromide in vitro.

An analytical procedure is described for the identification of the adducts formed by interaction of methyl bromide and haemoglobin. The reaction products of in vitro incubation of haemoglobin with methyl bromide have been characterised by electrospray mass spectrometry and gas chromatography-mass spectrometry. A prominent reactivity of several potential nucleophilic sites of haemoglobin was observed. Analogous results were recorded on blood samples of workers exposed to methyl bromide. The results obtained represent the basis for the complete structural characterisation of the modified haemoglobin and demonstrate the usefulness of the proposed analytical approach for the evaluation of alkylation degree and the identification of modified amino acids in proteins.

Alkylation↗
PubMed1995

Oxidative structural modifications of low density lipoprotein in homozygous familial hypercholesterolemia.

Patients with homozygous familial hypercholesterolemia (FH), as a result of the increased levels and prolonged residence time of low density lipoprotein (LDL) in plasma, have a strong tendency toward accumulation of LDL-cholesterol in the arterial wall, causing premature atherosclerosis. This phenomenon may enhance per se the physiological degradation of both protein and lipid component of LDL, which be more susceptible to oxidative damage induced by oxygen radicals. It is well known that LDL may undergo oxidative modification before being taken up by macrophages which are then transformed into foam cells. It has been suggested that platelet-activating factor (PAF) may play an important role in atherogenesis and PAF catabolism is known to be mediated by serum acetylhydrolase, an enzyme that is normally associated with LDL. Thus, the present study was designed to investigate the structural properties of LDL, including acetylhydrolase activity, in homozygous FH as compared to normolipidemic subjects before and after xanthine/xanthine oxidase-mediated oxidation. We studied 8 homozygous FH patients matched with 8 normolipidemic volunteers. Lipids of LDL fraction were extracted and verified by thin layer chromatography (TLC) analysis. Fatty acids were methylated and injected into a gas chromatograph/mass spectrometer. Vitamin E in LDL was determined by high performance liquid chromatography (HPLC). As an index of susceptibility of LDL to oxidative modifications, the formation of lipid-conjugated dienes was continuously monitored at 234 nm. Lipid peroxidation was also evaluated from the amount of both lipid peroxides (LPO) and malonyldialdehyde (MDA) content. Apolipoprotein (apo) B-100 on LDL was carried on polyacrylamide and agarose gel electrophoresis. In the homozygous FH patients, the relative content of cholesteryl ester was slightly increased. Interestingly, the relative amount of arachidonic acid (20:4) was constantly increased in each lipid fraction in homozygous FH patients. The amount of vitamin E was not significantly different in the patient group from that in the control group. However, LDL from patients carried lower levels of vitamin E (nmol/mg LDL) than controls (2.7 +/- 0.4 vs. 2.9 +/- 0.3 P = NS). The results shows that lag time (min) was decreased (82 +/- 19 vs. 111 +/- 21; P < 0.05) and the maximal rate of diene production and total diene production was increased in homozygous FH patients. Mean levels of MDA were similar in both groups before oxidation, but levels after initiation of oxidation were significantly higher in the patient group. In contrast, mean levels of LPO were already higher in patients before oxidation (58 vs. 27 nmol/mg of protein; P < 0.05), and after initiation of oxidation were also significantly higher at each time points. When oxidized LDL was run on a polyacrylamide gel, an extensive apo B-100 fragmentation replaced by lower molecular mass fragments ranging from 45,000 to 205,000 m.wt., was observed only in LDL from homozygotes. Relative LDL agarose gel mobility shows that LDL from patients migrated higher than LDL of controls. Finally acetylhydrolase activity associated with LDL in patients was significantly reduced as compared to controls. Thus, in homozygous FH patients, LDL appeared more susceptible to oxidation in vitro; the indices for LDL oxidizability were all significantly different from those of controls. This phenomenon might be due to prolonged residence time of LDL in these patients, as suggested from high basal LPO levels and lower vitamin E levels carried by LDL. This hypothesis may explain together with the high content of arachidonic acid, the enhanced susceptibility of LDL from homozygous FH patients to oxidative damage.

Apolipoprotein B-100↗
PubMed1995

Heparin and dialyzer membranes during hemodialysis: a literature review.

When patients with end stage renal disease (ESRD) are hemodialyzed, the thrombosis/hemorrhage dilemma occurs. The goal is to give enough, but not too much anticoagulant during the dialysis procedure. Heparin is the anticoagulant most widely used to prevent clotting while blood is in the dialysis circuit. This article discusses the relationship among blood, heparin and dialyzer membranes during the hemodialysis procedure. The information presented will help nephrology nurses recognize the necessity to reevaluate heparin prescriptions each time dialyzer changes are made or the medical conditions of patients change.

Heparin↗