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Biomedical subjects

M Valerio

Publications and source records attributed to M Valerio.

At least 19 recordsLinked to original sources
PubMed2005

Metabolic profiling by 13C-NMR spectroscopy: [1,2-13C2]glucose reveals a heterogeneous metabolism in human leukemia T cells.

Metabolic profiling is defined as the simultaneous assessment of substrate fluxes within and among the different pathways of metabolite synthesis and energy production under various physiological conditions. The use of stable-isotope tracers and the analysis of the distribution of labeled carbons in various intermediates, by both mass spectrometry and NMR spectroscopy, allow the role of several metabolic processes in cell growth and death to be defined. In the present paper we describe the metabolic profiling of Jurkat cells by isotopomer analysis using (13)C-NMR spectroscopy and [1,2-(13)C(2)]glucose as the stable-isotope tracer. The isotopomer analysis of the lactate, alanine, glutamate, proline, serine, glycine, malate and ribose-5-phosphate moiety of nucleotides has allowed original integrated information regarding the pentose phosphate pathway, TCA cycle, and amino acid metabolism in proliferating human leukemia T cells to be obtained. In particular, the contribution of the glucose-6-phosphate dehydrogenase and transketolase activities to phosphoribosyl-pyrophosphate synthesis was evaluated directly by the determination of isotopomers of the [1'-(13)C], [4',5'-(13)C(2)]ribosyl moiety of nucleotides. Furthermore, the relative contribution of the glycolysis and pentose cycle to lactate production was estimated via analysis of lactate isotopomers. Interestingly, pyruvate carboxylase and pyruvate dehydrogenase flux ratios measured by glutamate isotopomers and the production of isotopomers of several metabolites showed that the metabolic processes described could not take place simultaneously in the same macrocompartments (cells). Results revealed a heterogeneous metabolism in an asynchronous cell population that may be interpreted on the basis of different metabolic phenotypes of subpopulations in relation to different cell cycle phases.

Carbon Isotopes↗
PubMed1999

The management of shock and local injury in traumatic rhabdomyolysis.

Rhabdomyolysis (literally "striped muscle dissolution") is a biological and clinical condition that takes to plasmatic release of myoglobin, muscle enzymes and electrolytes, relates to the lysis of stripped muscle fibers. Rhabdomyolysis presents the clinician with two distinct problems: local injury and the systemic effects directly related to that injury. Locally, muscle, vessel and nerve compression are the primary issues. Systemic concerns relate to depleted intravascular volume, electrolyte imbalances and renal injury from myoglobin. Preventing the systemic and renal complications of the crush syndrome requires very early and vigorous treatment to sustain the circulation, preferably started at the site of the catastrophe. During the extrication of an injured person from a collapsed building, wrecked automobile, or other site, isotonic saline solution should be infused at the rate of 1.5 liters per hour as soon one of the trapped person's limbs has been freed. Some authors suggest to do a preventive fasciotomy in any suspicious case of compartmental syndrome, when the patient has severe muscular pain of the muscular cavity, tense swelling, hypoesthesia or anesthesia of the muscular cavity, pain at the passive mobilization of the limb. On the other hand other surgeons suggest doing a fasciotomy only in selected group of patients. Therefore, the traumatic rhabdomyolysis has few diagnostically problems. On the other hand, their treatment is complex and must have a multidisciplinary approach. So the rhabdomyolysis actually remain a severe disease with high mortality caused principally by visceral lesions related to sepsis.

Humans↗
PubMed1997

The use of television in 2- to 8-year-old children and the attitude of parents about such use.

BACKGROUND: It has been recognized that uncontrolled use of television (TV) in childhood is potentially harmful. Few data about family habits regarding TV use are available. OBJECTIVE: To evaluate the quantitative-qualitative TV viewing habits of children and the relationship between the attitudes of parents about TV programs and TV use by their children. DESIGN: Descriptive study. SETTING: General pediatric community. PARTICIPANTS: A convenience sample. All the parents of the children attending the nursery school, kindergarten, and the first 2 years of elementary school in a neighborhood of Padova, a city in northern Italy. The parents of 156 children (95%) responded. RESULTS: Nine percent of the children viewed TV for more than 3 hours per day, and 50% of the children viewed TV for 1 to 3 hours per day. A range of TV programs were viewed. Parents were involved in the TV use of their children; the most frequent way was by prohibiting some programs. The attitudinal profiles of the parents about the contents and the value of TV messages were notably associated with different kinds of TV use. A high score (ie, an optimistic judgment) on the attitudinal profile about the contents of TV programs was significantly associated with greater quantitative (P < .04), uncritical exposure (P < .05) of children to TV messages. A high score (ie, severe judgment) on the attitudinal profile regarding the values of TV programs was associated with qualitatively better exposure to TV (P < .05) and greater selectivity of programs watched (P < .05). In the parents, a critical attitude seemed to have a direct relationship with a higher social and educational level. CONCLUSIONS: This pilot study suggests that the attitude of parents about TV may influence the TV viewing habits of children. A broader study that accounts for this factor and other factors that influence TV use is necessary to better understand the reasons for the excessive exposure of children to TV.

Adult↗
PubMed1994

Deactivation of F0F1 ATPase in intact plant mitochondria. Effect of pH and inhibitors.

By using a method especially adapted to intact (pea leaf) mitochondria, we studied the regulation of the F0F1 ATPase by the electrochemical proton gradient (delta mu H+) and by the matricial pH. The kinetics of decay of the ATP hydrolase activity was studied immediately after the collapse of the electrochemical proton gradient by an uncoupler. At pH 7.5, three inhibitors of the ATPase (venturicidin, tri-n-butyl tin and aurovertin), used at non-saturating concentrations, inhibited ATP hydrolysis to the same extent throughout the decay. This showed that the activity was totally controlled by the ATPase during all the decay and rules out any involvement of the phosphate or nucleotide carriers. This interpretation was confirmed by the fact that carboxyatractyloside, an inhibitor of the ATP/ADP antiporter, had a strong effect only on the initial rate of ATP hydrolysis, but not on the rate measured after some tens of seconds of decay. Oligomycin, at variance with the other ATPase inhibitors, interfered with the deactivation process, suggesting that its effect depends on the conformational state of the enzyme. Between pH 6.5 and 7.5, the hydrolase activity rose continuously and was still kinetically controlled by the ATPase. At higher pH value, the activity slightly decreased and appeared limited by at least one of the carriers. The activity of the ATPase itself, free of any transport process, seemed to increase monotonously with pH from 6.5 to 8. The electrochemical proton gradient is required to maintain the ATPase active, whereas no effect can be observed on transport processes. Matricial pH, while modulating the apparent catalytic turnover, has no marked effect on the rate of deactivation. These results, obtained with intact mitochondria, extend previous observations on the isolated enzyme and question the binding of IF1 as a rate-limiting step for ATPase deactivation.

Adenosine Triphosphate↗
PubMed1993

Catalytic and activating protons follow different pathways in the H(+)-ATPase of potato tuber mitochondria.

The effect of some F0F1 inhibitors on the activation of the H(+)-ATPase by the electrochemical proton gradient was investigated in mitochondria extracted from potato tubers. Transient activated state of the ATPase was revealed by addition of ATP and of the detergent lauryldimethylamine oxide (LDAO) to energized mitochondria. Venturicidin, tri-n-butyltin and aurovertin at high concentrations did not affect the process of delta mu H(+)-activation, whereas oligomycin fully blocked it. The results support the idea of separate pathways or binding sites for catalytic and activating protons.

Aurovertins↗
PubMed1993

The electrochemical-proton-gradient-activated states of F0F1 ATPase in plant mitochondria as revealed by detergents.

ATP hydrolysis, triggered by the addition of polyoxyethylene-9-lauryl ether (Lubrol) or lauryldimethylamine oxide (LDAO) to energized plant mitochondria was studied in some details. The membrane disruption was quasi-instantaneous (2-3 s) with both detergents, as shown by the decrease of turbidity and the stopping of respiration. In pea leaf mitochondria, Lubrol triggered ATP hydrolysis in almost the same way as valinomycin plus nigericin, except that the activity was slightly stimulated and became insensitive to carboxyatractyloside. This allowed investigations of ATP hydrolysis without any interference of the ATP/ADP antiporter or the phosphate carrier. Lubrol did not prevent the ATPase from deactivating in pea leaf mitochondria, and did not trigger any ATP hydrolysis in potato tuber mitochondria. At variance with Lubrol, LDAO changed the properties of the F0F1 ATPase. It made the enzyme oligomycin insensitive and froze it in an activated state. The activity was also 5-8-times stimulated in pea leaf mitochondria. Moreover, LDAO revealed an important ATP hydrolase activity when added to energized potato tuber mitochondria. Despite the specific effect of LDAO, the activity triggered by this detergent strongly depended on the energized state of the organelles before detergent addition. From this study, it is concluded that the electrochemical proton gradient is completely necessary to activate the F0F1-ATPase in intact plant mitochondria, as known in chloroplasts and suggested by some reports in animal mitochondria. Moreover, it is suggested that the main difference between the enzymes of pea leaf and potato tuber mitochondria is their rate of deactivation after the collapse of the transmembrane electrochemical potential difference. Finally, when properly used, detergents appear to be a powerful tool to probe the state of the ATPase in intact mitochondria, and maybe in more integrated systems.

Adenosine Triphosphate↗
PubMed1993

Tissue specificity of the regulation of ATP hydrolysis by isolated plant mitochondria.

Pea leaf mitochondria had a high ATP hydrolase activity following the collapse of the membrane potential by addition of valinomycin in state 4. In mitochondria isolated from potato tubers such ATP hydrolase activity was not observed. Pea leaf mitochondria also had a delta pH, in contrast to what was previously found for potato tuber mitochondria. This delta pH could, however, not explain the different results on ATP hydrolysis since this activity was also observed in the presence of nigericin. The results suggest a tissue-specific regulation of ATP hydrolysis in resting organs (potato tubers) as compared to active organs (leaves).

Adenosine Triphosphate↗
PubMed1993

Methylmethacrylate monomer and fat content in shed blood after total joint arthroplasty.

Twenty-five patients were prospectively evaluated to quantify levels of methylmethacrylate monomer and fat in systemic blood and in shed blood after total joint arthroplasty. Levels of methylmethacrylate monomer in systemic blood were measured at intervals after insertion of the prosthesis. Levels of methylmethacrylate monomer in shed blood were measured at intervals after insertion of the drain. Levels of fat in systemic blood were measured preoperatively and 30 minutes after insertion of the prosthesis. Levels of fat in shed blood were measured 60 minutes after insertion of the drain. No significant fat or methylmethacrylate monomer was noted in systemic blood. Levels of methylmethacrylate monomer in shed blood were highest five minutes after insertion of the drain. Levels of methylmethacrylate monomer in shed blood collected from the hip were significantly lower than levels in shed blood from the knee. Levels of shed blood from the hip and knee were undetectable six hours after insertion of the drain. Shed blood from the hips and knees contained fat particles of three diameters: fat particles less than 9 microns, 9-40 microns, and greater than 40 microns. The diameter of most of the fat particles in the shed blood was less than 9 microns. Fat particles less than 40 microns in diameter will not be removed by microaggregate screen filters 40 microns in diameter.

Blood Loss, Surgical↗
PubMed1992

An attempt to discriminate catalytic and regulatory proton binding sites in membrane-bound, thiol-reduced chloroplast ATPase.

The question of the possible identity of catalytic and regulatory proton pathways in the chloroplast FoF1 ATPase has been studied using different energy-transfer inhibitors. Venturicidin, a reversible inhibitor of Fo, affects neither the delta mu H(+)-dependent thiol reduction of the membrane-bound chloroplast ATPase nor its ability to be activated by the proton gradient. It seems therefore to block only the proton flow required by the catalytic function of the enzymes. Venturicidin, however, also slows down the deactivation of the thiol-reduced ATPases during uncoupled ATP hydrolysis, following a delta mu H+ activation, but phloridzin, a reversible F1 inhibitor, has the same effect. Tentoxin, an irreversible F1 inhibitor, decreases the rate of ATP hydrolysis but does not affect the rate of deactivation. These findings suggest that catalytic and regulatory H(+)-binding sites are different. No distinction can be made, if any, between protons involved in unmasking the thiol-sensitive groups of F1 and in activating the enzyme. The effect of venturicidin and phloridzin on the deactivation is consistent with an inhibitory effect of newly formed--by ATP hydrolysis--ADP molecules, which might affect the enzyme without passing through the medium. Phosphate at millimolar concentration has an effect similar to low concentrations of phloridzin and venturicidin, probably by a simple back-reaction effect.

Adenosine Triphosphate↗
PubMed1982

Spontaneous paramyxoviral encephalitis in nonhuman primates (Macaca mulatta and M. nemestrina).

Two female rhesus macaques (Macaca mulatta) and one female pigtailed macaque (M. nemestrina) developed acute neurological signs including ataxia, muscular incoordination, and seizures. Light microscopy showed Cowdry Type A intranuclear inclusion bodies in astrocytes and neurons of the cerebral cortex and Purkinje's cells of the cerebellum. Many cells also had intracytoplasmic inclusion bodies. Electron microscopy identified paramyxoviral nucleocapsids in the intranuclear and intracytoplasmic inclusions in two monkeys. We believe these monkeys had measles encephalitis because measles virus is the only paramyxovirus known to cause inclusion bodies in macaques and because the lesions in these monkeys resembled measles encephalitis in man.

Animals↗
PubMed1980

Herpesvirus saimiri-induced malignant lymphoma in inbred strain III/J rabbits (Oryctolagus cuniculus).

Four young strain III/J rabbits of both sexes were inoculated with a single dose of prototype partially purified Herpesvirus saimiri (HVS) via IV and IM routes. All inoculated animals had enlarged lymph nodes, and significant levels of antibodies to HVS early, late, and membrane antigens were detectable during the infection. The animals died or were killed and HVS was isolated from the peripheral blood mononuclear cells and the various lymph nodes but not from the kidney. Microscopic examination showed that these animals had poorly differentiated lymphomas. The response of mononuclear cells to PHA from peripheral blood of infected animals showed depressed cell mediated immune responses. Humoral and cellular immunity responses during tumorigenesis were comparable to those reported in nonhuman primates with HVS-induced tumors. Thus, the inbred strain III/J appears to be an inexpensive suitable model for studies of oncogenic herpesvirus-induced cancers.

Animals↗
PubMed1980

Morphological, growth, and chromosomal changes in bovine pancreatic duct epithelial cells exposed to N-methyl-N'-nitro-N-nitrosoguanidine.

Epithelial cells cultured from bovine pancreatic ducts were given a single treatment of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Multinucleated cells and giant cells were observed more frequently in carcinogen-treated cultures than in controls. The MNNG-treated cultures also contained a sizeable population of small, dense cells that were not observed in control cultures. At the concentration of 1.0 microgram/ml, MNNG caused an initial depression in the growth rate of the cells followed by growth stimulation for several weeks. The MNNG produced chromosomal damage in the cells as indicated by the observation that a substantial proportion of carcinogen-treated cells were heteroploid and contained a high frequency of metacentric and submetacentric chromosomes and a dicentric marker chromosome. The MNNG treated and control cultures did not acquire the ability to grow in soft agar or to produce tumors after transplantation into athymic, nude mice.

Agar↗