Visceral pain: pathophysiology and clinical aspects.
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Humans↗
Biomedical subjects
M Maresca
Publications and source records attributed to M Maresca.
Hydroxyapatite formation in the presence of proteoglycans of reduced sulfate content: studies in the brachymorphic mouse.
Proteoglycans from the brachymorphic (bm/bm) mouse have a reduced sulfate content due to the impaired activity of adenosine phosphosulfate phosphokinase in these animals. X-ray diffraction and infrared analyses of the mineral from the calcified cartilage of the bm/bm mice demonstrate the presence of significantly larger and more perfect hydroxyapatite crystals of lower carbonate to phosphate content than crystals found in the control animals. No differences were seen in the mineral content, crystallite size, CO3:PO4 ratio, or infrared splitting factors measured in the diaphyseal bone from these animals. Electron microscopic examination similarly shows larger, more disorganized crystals in the bm/bm animals' calcified cartilage as contrasted with controls. In vitro, proteoglycan aggregates from these dwarf mice are shown in a collagen gel-growth system to be less effective inhibitors of hydroxyapatite formation and growth than similarly size sulfated proteoglycans from age-matched control animals. The proteoglycans from the control mice were comparable in inhibitory ability to proteoglycan aggregates extracted from fetal bovine epiphyses. The in vitro and in vivo mineral parameters suggest the importance of sulfate for the interaction between proteoglycans and mineral in growth plate calcification.
Animals↗
Antiplatelet effect of 2-(diethylamino)-7-hydroxychromone.
In this study the in vitro influence of 2-(diethylamino)-7-hydroxychromone (RC39II) on platelet aggregating responses, thromboxane A2 (TxA2) production, release reaction and intraplatelet cyclic AMP (cAMP) content has been investigated. The drug exerts a dose-dependent inhibitory effect on aggregating response to arachidonic acid, U46619, thrombin, collagen and calcium ionophore A23187. Inhibiting concentrations of RC39II also prevent platelet release reaction and TxA2 formation. RC39II potentiates platelet cAMP accumulation by Iloprost. Several studies, carried out on soluble cAMP phosphodiesterase (PDE) have shown that the drug inhibits phosphodiesterase in a dose-dependent manner. No effect was shown on adenylate cyclase activity from platelet membranes.
Blood Platelets↗
Oxidative metabolism of human platelets.
The reducing capacity toward cytochrome c present in human resting platelets increases upon platelet stimulation, and is partially inhibited by superoxide dismutase. This activity therefore represents the generation of superoxide anion. In order to evaluate hydrogen peroxide formation a quantitative assay by mean of dichlorofluorescin (DCFH) has been set up. The DCFH, trapped inside the cell, is oxidized by hydrogen peroxide to the fluorescent compound DCF. Basal DCF increases during activation of platelets by agonists. Arachidonic acid, calcium ionophore A23187 and to a lesser extent PMA and thrombin are the most effective. N-ethylmaleimide induces a dose-dependent DCFH oxidation and potentiates the effect of agonists. NAD(P)H--cytochrome c reductase enzyme, which catalyzes superoxide anion production, is present in platelets at high specific activity, as well as those enzymes who protect the cells from oxygen reactive species.
Blood Platelets↗
Concentration-dependent effects of dentin phosphophoryn in the regulation of in vitro hydroxyapatite formation and growth.
The effect of dentin phosphophoryn on hydroxyapatite formation and growth was studied in an in vitro gelatin gel diffusion system. Phosphophoryn, in low concentrations (0.010-1 microgram/ml) promoted de novo hydroxyapatite formation; at a higher concentration (100 micrograms/ml) in the same system, the dentin matrix protein inhibited hydroxyapatite growth. Similar inhibition of hydroxyapatite growth was seen in solution. The intact phosphophoryn was not essential for either inhibition of seeded growth or promotion of mineralization, since the formic acid degraded protein was comparably effective. Transmission electron microscopy of the precipitates formed at 7 days showed no significant differences in crystallite size distribution in the presence and absence of phosphophoryn. However there was a dose-dependent decrease in the number of mineral clusters formed in the presence of increasing amounts of phosphophoryn, suggesting inhibition of secondary nucleation. These data provide support for the postulated 'multifunctional' role of the dentin phosphoprotein in the mineralization process.
Animals↗
Platelets of patients affected with essential thrombocythemia are abnormal in plasma membrane and adenine nucleotide content.
The adenine nucleotides present in distinct cellular compartments of platelets of 27 patients affected with essential thrombocythemia have been measured. In order to quantify granule-bound nucleotides and adenylic cytoplasmic pool, platelets have been stimulated with thrombin or treated with increasing digitonin concentrations, respectively. Among patients, we have identified two groups: 12 patients (Group 1) had normal platelet level of ATP and ADP both in dense granules as well as in cytoplasmic pool. The other patients (Group 2) had granule ATP and ADP significantly lower and ATP/ADP ratio significantly higher than controls. In these patients an increase in hypoxanthine level, derived from metabolic ATP degradation occurring during stimulation, was observed. In addition, in the latter patients an increased resistance of plasma membrane to digitonin was shown, suggesting that membrane fluidity should be reduced owing to a modified cholesterol/phospholipid ratio.
Adenine Nucleotides↗
Inhibition of the glycolytic pathway by methylglyoxal in human platelets.
The incubation of human platelets with methylglyoxal and glucose produces a rapid transformation of the ketoaldehyde to D-lactate by the glyoxalase system and a partial reduction in GSH. Glucose utilization is affected at the level of the glycolytic pathway. No effect of the ketoaldehyde on glycogenolysis and glucose oxidation through the hexose monophosphate shunt was demonstrated. Phosphofructokinase, fructose 1,6 diphosphate (F1, 6DP) aldolase, glyceraldehyde 3-phosphate dehydrogenase and 3-phosphoglycerate mutase were mostly inhibited by methylglyoxal. A decrease in lactate and pyruvate formation and an accumulation of some glycolytic intermediates (fructose 1,6 diphosphate, dihydroxyacetone phosphate, 3-phosphoglycerate) was observed. Moreover methylglyoxal induced a fall in the metabolic ATP concentration. Since methylglyoxal is an intermediate of the glycolytic bypass system from dihydroxyacetone phosphate to D-lactate, it may be assumed that ketoaldehyde exerts a regulating effect on triose metabolism.
Adenine Nucleotides↗
The effects of noncollagenous matrix proteins on hydroxyapatite formation and proliferation in a collagen gel system.
The effects of several noncollagenous matrix proteins on hydroxyapatite formation and growth were studied in a dynamic collagen gel system. In this system growth plate proteoglycan aggregates at concentrations of 1-10 micrograms/ml were effective inhibitors, desulfated aggregates from brachymorphic mice were less effective. Phosphophoryn at 1-100 micrograms/ml had no effect on formation; 60-120 micrograms/ml retarded mineral growth. Type X collagen at concentrations of 50-300 micrograms/ml had no effect on formation or growth.
Calcification, Physiologic↗
Alkaline extraction and reverse-phase high-performance liquid chromatography of adenine and pyridine nucleotides in human platelets.
The levels of adenine (ATP, ADP, AMP) and pyridine (NAD, NADH) nucleotides in human platelets have been measured by a simple and reproducible method. A rapid alkaline extraction allows a complete recovery of the compounds concerned. The metabolic ATP and ADP in the cytosolic fraction, the amount released upon thrombin stimulation, and the ADP bound to F-actin have also been evaluated. Analysis was performed by reverse-phase, isocratic high-performance liquid chromatography on a 5-microns Lichrosorb RP-18 column with uv detection at 254 nm.
Adenine Nucleotides↗
Platelet glucose metabolism in type I diabetic subjects.
In a group of 35 type I diabetics, platelet glycolytic and glycogenolytic flux have been measured. In type I diabetic platelets glucose uptake was significantly reduced. The quite normal lactate production was obtained by a faster utilization of stored glycogen in these patients. Specific activity of glycolytic enzymes was normal, in particular the levels and kinetic properties of soluble and membrane bound hexokinase. The rate of glucose flux through the hexose monophosphate shunt, measured either in resting or in arachidonic acid-stimulated platelets, was normal in diabetics. Kinetics of glucose transport across plasma membrane have also been determined. Km was significantly increased in diabetic patients. No changes was shown in Vmax. Modifications present in membrane organization of patients could involve glucose transport protein.
Adult↗
Lateralisation of pain in cluster headache.
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Adolescent↗
[Trigeminal neuralgia due to ill-fitting dentures].
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Aged↗
Effect of diabetes mellitus on selected acid hydrolase activities in human platelets.
Platelets were isolated from blood donated by 57 diabetic subjects, 41 insulin-dependent and 16 non insulin-dependent, ranging in age from 19 to 78 years, and by 54 healthy non-diabetic subjects ranging from 19 to 63 years of age. The platelets were ruptured by sonication and resultant preparations assayed for their levels of activity of seven acid glycohydrolases. Platelets from diabetic subjects contained only 50% of the alpha-L-fucosidase activity and about 60% of the acid phosphatase, beta-D-galactosidase, and beta-D-glucosidase activities of platelets from non-diabetic individuals; the differences were statistically significant. N-acetyl-beta-D-glucosaminidase activity in platelets from diabetic subjects was reduced by about 15% from normal levels while beta-D-glucuronidase and alpha-D-mannosidase activities were similar to those from non-diabetic individuals. A comparison of the data from older insulin-dependent diabetic and normal subjects with a similar age distribution yielded identical results for the two groups in all enzymes tested except fucosidase. Platelets of non insulin-dependent diabetics and those from non-diabetic subjects of a similar age distribution appear to possess similar levels of these acid hydrolases. There was no difference in levels of these platelet acid hydrolases between males and females in either the diabetic or non-diabetic group. Within the diabetic group, there was no difference in these platelet acid hydrolase activities between subjects with retinopathy and without retinopathy. There was no correlation of the enzyme activity levels of platelets from diabetic subjects with concentration of glycosylated haemoglobin, serum triglycerides or serum cholesterol.
Acid Phosphatase↗
Clinical approach to visceral sensation.
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Humans↗
Lysosomal enzymes in human platelets.
In human freshly prepared platelets the following lysosomal enzymes were studied: alpha-mannosidase, alpha-fucosidase, beta-galactosidase, beta-glucosidase, beta-glucuronidase, beta-N-acetylglucosaminidase and acid phosphatase. For each of the examined enzymes the conditions providing maximal activity (pH, buffer), kinetic parameters (saturating substrate concentration and Km) as well as heat stability were established. On the basis of these parameters it is suggested that many of the serum glycohydrolases may be platelet derived.
Acid Phosphatase↗
Lactate overproduction in platelets of subjects affected with myeloproliferative disorders.
In platelets of patients affected with myeloproliferative disorders, glycolytic and glycogenolytic flux have been examined. Results of studies on glucose uptake, glycogen breakdown and lactate formation have been reported. No difference in glucose uptake between controls and patients was observed, but in patients a higher lactate formation was always noted in the presence or absence of exogenous glucose, in correlation with a higher glycogen breakdown rate. Results could be explained by modified regulation mechanisms on glycogen phosphorylase.
Adult↗
Some aspects of platelet glucose metabolism in thrombocytosis due to myeloproliferative disorders.
Some aspects of the glucose metabolism were investigated in platelets of 11 healthy donors and 11 patients suffering from thrombocytosis due to myeloproliferative disorders. Out of all the glycolytic compounds measured in resting platelets, dihydroxyacetonephosphate and fructose 1,6 bisphosphate were significantly higher in cells of subjects with thrombocytosis. No difference was observed in the basic net flux of glucose through the hexose monophosphate shunt. Addition of arachidonic acid to platelets of patients with thrombocytosis had a very poor effect in stimulation of the hexose monophosphate shunt, whereas high values of activation were obtained in control platelets. Lactate production determined by collagen was found significantly higher in all patients. These data observed in platelets of patients could be explained by a decreased pool of metabolic adenine nucleotides.
Adult↗
Platelet membrane fatty acids in thrombocytosis due to myeloproliferative disorders.
The fatty acid composition of platelet membranes has been analysed in patients with thrombocytosis due to myeloproliferative disorders, who had not taken any drugs. A significant increase in palmitic and oleic acid, together with a decrease in stearic, linoleic and arachidonic acids was observed. The fatty acid pattern of platelet membranes was also analysed in patients during treatment with ASA (acetylsalicylic acid). ASA ingestion completely normalizes the platelet content of palmitic acid and partially that of stearic and arachidonic acid, whereas it has no effect on the level of linoleic acid and raises that of oleic acid. The altered pattern of fatty acids observed in patients may interfere with platelet function by decreasing membrane fluidity. Treatment of patients with ASA seems to act on platelet membranes by partially normalizing the fatty acid composition.
Adult↗