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Biomedical subjects

L Marzio

Publications and source records attributed to L Marzio.

At least 55 records · Page 3Linked to original sources
PubMed1994

Coccoid Helicobacter pylori not culturable in vitro reverts in mice.

An experimental rodent model was used to demonstrate the viability of the coccoid form of Helicobacter pylori. Concentrated suspensions were prepared for the two different morphologies: at 2 days incubation for the bacillary forms and at 20 days incubation for the "dormant" forms. The strains used for incubation were two fresh isolates from humans with duodenal ulceration, and two collection strains. Five hundred microliters of culture (OD550 = 5 Mc Farland) of Helicobacter pylori with bacillary (2-5 x 10(9) CFU/ml) and coccoid (0 CFU/ml) morphology were inoculated intragastrically in BALB/c mice. The gastric mucosa of the mice was colonized by Helicobacter pylori with the administration of fresh bacillary and coccoid cultures and not with the established cultures. Helicobacter pylori was isolated at 1 week after inoculation with the administration of fresh bacillary cultures, while fresh coccoid Helicobacter pylori was recovered in mice stomachs after 2 weeks of inoculation. After colonization, histopathologic changes occurred after 1 month from inoculation; all colonized mice showed a systemic antibody response to Helicobacter pylori. These results support the thesis of the viability of coccoid Helicobacter pylori non-culturable in vitro and confirm that concentrated bacterial suspensions are able to colonize and to produce gastric alterations in this suitable animal model.

Administration, Oral↗
PubMed1994

H2-receptor antagonists are scavengers of oxygen radicals.

Potential oxygen radical scavenging properties of the H2-receptor antagonists cimetidine, ranitidine and famotidine were investigated. These drugs, although ineffective against superoxide anion and hydrogen peroxide, can scavenge hydroxyl radical (OH.) with a very high rate constant, which is about tenfold higher than that of the specific scavenger mannitol for famotidine (1.7 x 10(10) mol-1 s-1) and cimetidine (1.6 x 10(10) mol-1 s-1), ranitidine displaying a rate constant of 7.5 x 10(9) mol-1 s-1. These OH. savenging effects are significant beginning from 10, 28 and 100 mumol l-1 concentration for famotidine, cimetidine and ranitidine, respectively, thus suggesting that the drugs may effectively act as OH. scavengers in vivo especially in the gastric lumen. Only cimetidine can apparently bind and inactivate iron, which further emphasizes its antioxidant capacity. Moreover, all drugs, even at 10 mumol l-1 concentration, show powerful scavenging effects on hypochlorous acid and monochloramine, which are cytotoxic oxidants arising from inflammatory cells, such as neutrophils. These data suggest that some therapeutical effects of H2-receptor antagonists in peptic ulcer may also be related to their antiradical-antioxidant capacity, and that these drugs could potentially be used in other disease entities characterized by free radical-mediated oxidative stress in vivo.

Chloramines↗
PubMed1993

Hypoxia-induced coronary flow changes in the perfused rat heart: effects of high L-carnitine concentrations.

1. Hemodynamic effects of physiological (0.04 and 0.07 mM) and high (8, 15 and 25 mM) L-carnitine (LC) concentrations were tested on the normally oxygenated and hypoxic perfused rat heart. 2. No effect was detected on aerobic hearts, whereas a dose-dependent rise in coronary flow (CF) during both the hyperemic and constrictive phases was observed in hypoxic hearts with 8, 15 and 25 mM LC. This action was apparently unrelated to a resting tension (RT) improvement, which was observed only with 25 mM LC. 3. When 11 mM glucose was replaced by 11 mM mannitol in the perfusion buffer, LC effects on the hyperemic phase were abolished; however, 25 mM LC resulted in CF-values still significantly higher than those detected without the drug, though RT was similar in these glucose-free groups. 4. It may be concluded that LC is ineffective on the perfused rat heart in aerobic conditions, whereas high LC concentrations can enhance CF only during hypoxia, these effects being independent of heart function improvements and partly unrelated to glucose presence.

Aerobiosis↗
PubMed1993

[Efficacy and tolerability of cisapride in a new formula of 10 mg effervescent capsules for the treatment of functional dyspepsia].

The efficacy and tolerability of Cisapride effervescent granules and a metoclopramide-dimethicone combination were compared double-blind in two comparable groups of 15 patients each with dyspepsia. All patients received three sachets daily of either drug for 6 consecutive weeks. As for efficacy, Cisapride effervescent granules was found to reduce 85% (11/13) of symptoms to a statistically significant extent, as against 42% (5/12) in the reference group. Statistical analysis showed Cisapride effervescent granules to be more effective than the reference drug for 6 out of 11 evaluable symptoms. Mean global improvement was 86% for Cisapride effervescent granules vs 41% for the reference combination. Final judgment by the physician was more favorable for Cisapride effervescent granules than for the reference drug (p < 0.0001). Treatment withdrawal was never necessary and no significant changes of laboratory values were observed. No statistically significant difference between the two treatments as to tolerability was observed. In conclusion, Cisapride effervescent granules was found to have a better risk/benefit ratio than the reference combination.

Adult↗
PubMed1993

[A new granular effervescent 10-mg formulation of cisapride in the treatment of gastroesophageal reflux].

The efficacy and tolerability of Cisapride effervescent granules for treatment of gastroesophageal reflux disease were compared to a metoclopramide-dimeticone combination. The double-blind study was performed in two groups of 10 patients each who received 3 sachets daily of either drug for 8 weeks. Cisapride effervescent granules induced a statistically significant improvement of 75% of symptoms (6/8) while this improvement was obtained with the reference drug for only 60% (3/5). Statistical evaluation showed Cisapride effervescent granules to be more effective than the reference drug for 2 of 5 evaluable symptoms; mean global improvement amounted to 83 vs 58%. Final physician opinion was more favorable to Cisapride effervescent granules than to the reference drug (p < 0.005). Treatment did not have to be withdrawn nor were clinically significant changes of laboratory values observed. Both drugs were found to be well tolerated without differences between the two groups. Three patients treated with Cisapride effervescent granules complained of short-lasting mild abdominal discomfort the relations of which to the drug was doubtful, and which subsided spontaneously without need to withdraw treatment or to apply other types of therapy.

Adult↗
PubMed1992

Heparin: does it act as an antioxidant in vivo?

Previous studies have shown that heparin antagonizes oxygen radical-mediated injury to endothelial cells, suggesting an antioxidant role of the drug. In the present investigation, the hypothesis that heparin exerts direct antioxidant effects was tested in several experimental models. We have found that 1, 3, 5, 10, 20, 40 and 80 U/mL of heparin do not scavenge superoxide anion, hydrogen peroxide, hydroxyl radical or the stable free radical 1,1-diphenyl-2-pycrylhydrazyl. Moreover, the drug is ineffective towards iron-driven linolenic acid peroxidation, autooxidation of brain homogenate and linolenic acid peroxidation mediated by human internal mammary artery homogenate. Specific studies on the potential iron-binding-inactivating capacity of heparin prove the drug to be totally ineffective. Finally, the loss of protein sulphydryls from human plasma induced by hypoxanthine-xanthine oxidase-generated oxygen radicals is not prevented by heparin. In conclusion, heparin, even at concentrations far higher than those usually used therapeutically, has no direct antioxidant properties. Thus, other mechanisms not strictly antioxidant-type must be involved in heparin-mediated cell protection against toxic oxygen metabolites.

Animals↗
PubMed1992

Gallbladder hypokinesia and normal gastric emptying of liquids in patients with dyspeptic symptoms. A double-blind placebo-controlled clinical trial with cisapride.

Gastric and gallbladder emptying after a standard liquid meal were studied in 65 patients with early satiety, bloating, pain at the right hypochondrium or the epigastrium, nausea, and occasionally vomiting. Fifty normal subjects were studied as a control group. Gastric and gallbladder emptying were evaluated by means of real-time ultrasonography (RUS). Serial RUS scans were made after a 12-hr fast and every 15 min after a standard meal for 2 hr. Patients were considered to have delayed gastric emptying or hypokinetic gallbladder when gastric diameters and gallbladder volume evaluated 45 min after meal were 2 SD above the corresponding mean values of the normal subject group. Fifteen patients (23%) were found with delayed gastric emptying and 20 (30.7%) a reduced gallbladder emptying. None of our patients showed delayed gastric emptying and hypokinetic gallbladder simultaneously. The 20 patients with reduced gallbladder emptying were included in a double-blind randomized, placebo controlled, change-over study with cisapride (10 mg three times a day) for 30 days. Cisapride treatment reversed the gallbladder hypomotility within the normal range while placebo did not change the response to meal. Symptom score improved significantly after cisapride and placebo. It is concluded that in dyspeptic patients with reduced gallbladder response to a meal cisapride may be of help in improving the kinetic abnormality. Dyspeptic symptoms, however, do not seem to be corrected with the described gallbladder motor abnormality.

Adult↗
PubMed1992

Role of oral cholecystography, real-time ultrasound, and CT in evaluation of gallstones and gallbladder function.

The capacity of oral cholecystography (OCG), real-time ultrasound (RUS), and computed tomography (CT) to detect gallstones and to analyze their size, number, and composition was tested preoperatively in 37 patients undergoing elective cholecystectomy. Gallbladder response to a standard meal was also evaluated by OCG and RUS. Gallstones were analyzed chemically for calcium, cholesterol, and bilirubin content. The results show that RUS is the most valuable test for detecting gallstones and is similar to OCG in measuring their size and number, whereas CT underestimates the stone size. Gallbladder function in terms of contractibility can be evaluated by RUS and OCG, but RUS provides useful information even if the gallbladder is not opacified at OCG. CT is more accurate than OCG in detecting the presence of calcium, and CT attenuation numbers are positively correlated with calcium content of the stone (r = 0.87, p less than 0.01).

Cholecystography↗
PubMed1992

Distribution of mast cells in intestinal muscle of nematode-sensitized rats.

We examined the distribution and functional integrity of mast cells in intestinal longitudinal muscle in rats sensitized by two previous infections with Trichinella spiralis. A segment of jejunum was excluded from the gut before infection, and the remainder of the gut was anastomosed. Few mast cells were seen in muscle of noninfected control rats except in the region of the jejunal anastomosis. In rats sensitized by T. spiralis infection, mast cells were increased in number in the jejunum and the number of mast cells followed an aboral gradient down the entire length of the gut in continuity. In addition, mast cells were present in muscle of the excluded segment of sensitized rats. All mast cells were stained red with safranin. Functional integrity was assessed by the ability of mast cells to induce contraction after degranulation by antigen. In muscle from sensitized rats, contraction was induced in each region after exposure to T. spiralis antigen but not Nippostrongylus brasiliensis antigen. Contraction was inhibited by the mast cell stabilizer doxantrazole and the 5-hydroxytryptamine (5-HT) antagonist cyproheptadine. When antigen-induced contraction was expressed as a percentage of the maximum response of the tissue to exogenous 5-HT, the magnitude of contraction decreased along an aboral gradient down the intestine and correlated well (r2 = 0.878) with mast cell numbers. These results suggest that the increase in connective tissue mast cells in gut muscle after T. spiralis infection involves both local and systemic mechanisms.

Animals↗
PubMed1992

Circadian variations in antioxidant defences and lipid peroxidation in the rat heart.

Circadian variations in antioxidant defences and lipid peroxidation were investigated in 12 rat hearts perfused during light (i.e., at 08.00, n = 6) and dark cycle (i.e., at 19.00, n = 6). Higher levels of non proteic thiol compounds (P < 0.01), glutathione transferase activity (P < 0.05) and lipid peroxidation (P < 0.01) were detected in evening-excised hearts, associated with a lower (P < 0.05) selenium-dependent glutathione peroxidase activity; superoxide dismutase and glutathione reductase activities, as well as vitamin E content, were similar in the two groups. Moreover, a greater release of thiobarbituric acid reactive substances (P < 0.01) and proteins (P < 0.05) was detected in the myocardial effluent of another group of 5 evening-excised hearts perfused with Krebs-Henseleit buffer containing 30 microM cumene hydroperoxide, as compared to 5 light-cycle hearts. In conclusion, a higher oxidative stress seems to be operative in the rat heart during early stages of the dark phase, in spite of the increase level of non proteic thiol compounds (namely, glutathione). An imbalance of antioxidant defences, and/or higher radical generation and unsaturation degree of biomembranes lipids, may be hypothesized to favour myocardial oxidative stress at the beginning of the motor activity phase in rats.

Animals↗
PubMed1992

Effects of high fat-, cholesterol-enriched diet on the antioxidant defence mechanisms in the rabbit heart.

In 7 rabbits fed on hyperlipidic diet (0.5% cholesterol, 5% peanut oil and 5% lard) for 4 weeks, the ventricular myocardium was tested for antioxidant defences and thiobarbituric acid reactive substances. Seven age-matched rabbits served as controls. The hearts were previously subjected to 45 min Langendorff perfusion to study coronary flow, developed tension and resting tension; coronary effluent values of CPK activity, pH and UV absorbance at 250 nm (i.e., low molecular weight ATP catabolites) were also investigated. After 4 weeks of diet, a significant rise of plasma cholesterol (P < 0.0001) and triglycerides (P < 0.0001) was observed. Total superoxide dismutase, catalase and glutathione transferase activities underwent a significant increase (P < 0.05) in the hyperlipidemic animals. On the contrary, a depression of glutathione reductase (P < 0.01) and selenium-dependent glutathione peroxidase (P < 0.01) activities, associated with decreased levels of non proteic thiol compounds (P < 0.01), was assessed. The selenium-independent glutathione peroxidase activity was not detectable in both groups. Thiobarbituric acid reactive substances levels were significantly increased in the hyperlipidemic rabbit myocardium (P < 0.01). Even though heart hemodynamics, CPK release and perfusate pH did not differ in control and experimental animals, higher 250 nm absorbance values (P < 0.05) were detected in the myocardial effluent of hyperlipidemic rabbits. In conclusion, high fat-, cholesterol-enriched diet induces an imbalance in the rabbit heart antioxidant defences, some of which are increased, whereas others are depressed, eventually resulting in enhanced myocardial lipid peroxidation. These biochemical changes are associated with higher perfusate values of UV absorbance at 250 nm, but not with significant CPK leakage or myocardial hemodynamics derangement.

Adenosine Triphosphate↗
PubMed1992

Octylonium bromide in the treatment of the irritable bowel syndrome: a clinical-functional study.

We investigated the effect of octylonium bromide on a number of symptoms and functional aspects of the irritable bowel syndrome. Seventy-two patients complaining mainly of abdominal pain were studied in a double-blind trial (octylonium bromide 40 mg tid for 4 weeks or placebo). Clinical parameters were: abdominal pain, bloating and bowel frequency. Sigmoid manometry with simultaneous recording of the thresholds for distension and/or pain upon graded inflation of an endoluminal balloon was performed before and at the end of treatment. In contrast to placebo, octylonium bromide significantly reduced pain and bloating, and significantly increased (p < 0.02) the pain threshold throughout the treatment period. However, comparison with the placebo group failed to show any relevant differences. Neither treatment influenced the frequency of bowel movement. Sigmoid motility during distension was significantly reduced after octylonium bromide (p < 0.05), but it did not change after placebo. In conclusion, octylonium bromide is capable of reducing symptoms and motor reactivity of the sigmoid in patients with irritable bowel syndrome.

Abdominal Pain↗
PubMed1991

Enhanced clearing of Helicobacter pylori after omeprazole plus roxithromycin treatment.

The in vitro antibacterial activity of omeprazole against eight strains of Helicobacter pylori was evaluated. Minimum inhibitory concentration (MIC) values were 32 micrograms/ml and 64 micrograms/ml (MIC50 and MIC90 respectively). We performed a randomized single blind study comparing the efficacy of omeprazole alone (for 4 weeks) or combined with roxithromycin (for 2 weeks) in the treatment of duodenal ulcer and chronic active gastritis associated with H. pylori infection, H. pylori was eradicated in 75% of patients treated with omeprazole alone whereas the patients treated with the combination of these drugs were completely free from H. pylori at the end of the therapy.

Drug Combinations↗
PubMed1991

Aortic glutathione-related antioxidant defences in rabbits subjected to suprarenal aortic coarctation hypertension.

In seven rabbits subjected to suprarenal aortic coarctation hypertension, the segments above and below the coarctation were tested for the antioxidant defences (i.e. acid-soluble thiol compounds, selenium-dependent and selenium-independent glutathione peroxidase, glutathione reductase, glutathione transferase) and thiobarbituric acid-reactive substances. Seven sham-operated rabbits served as controls. Systolic blood pressure proximal to the ligature increased significantly with respect to pre-operative values after 16 days (117 +/- 8.3 vs 71.7 +/- 5.2 mmHg, P less than 0.05), while pressure distal to the ligature remained normotensive. Higher values of acid-soluble thiol compounds, thiobarbituric acid-reactive substances and increased activities of selenium-dependent glutathione peroxidase, glutathione reductase and glutathione transferase were assayed in the suprarenal with respect to the subrenal segment in both groups. However, the values of the upper segments were more elevated in the experimental group than in controls, but no differences were observed in the lower segments. Glutathione peroxidase activity assayed with cumene hydroperoxide was higher than the activity assayed with hydrogen peroxide in the hypertensive segments, but no differences were detected in the substenotic and control segments. Furthermore, an isoenzymatic form of glutathione transferase, analogous to rat 8-8 glutathione transferase isoenzyme, was detected by immunodiffusion in the hypertensive aorta. The following conclusions may be drawn: (1) a biochemical gradient in glutathione-related enzymes, acid-soluble thiol compounds and thiobarbituric acid-reactive substances between the proximal and distal aorta seems to exist in control rabbits; (2) suprarenal aortic coarctation induces a significant increase in glutathione-related antioxidant defences and thiobarbituric acid-reactive substances of the hypertensive aortic wall.

Animals↗
PubMed1991

Regional distribution of glutathione-related antioxidant defences in the normal rabbit aorta.

In 6 normal rabbits, the aortic arch, the descending thoracic and the abdominal aorta were tested for non proteic thiol compounds, selenium-dependent and selenium-independent glutatione peroxidase, glutatione reductase, glutatione transferase and thiobarbituric acid reactive substances. The aortic arch showed the greatest content of non proteic thiol compounds and thiobarbituric acid reactive substances, associated to the highest activities of glutathione-related enzymes. However, not significant differences were detectable between aortic arch and descending thoracic aorta, except for the glutathione transferase activity (0.395 +/- 0.031 vs 0.330 +/- 0.053 U/mg protein, p less than 0.05). Furthermore, both aortic arch and descending thoracic aorta showed significantly higher values of non proteic thiol compounds (46.05 +/- 10.15% and 33 +/- 13.5%, p less than 0.05), selenium-dependent glutathione peroxidase activity (70.35 +/- 26% and 54.3 +/- 9.5%, p less than 0.05), glutathione reductase activity (25.4 +/- 7% and 18.4 +/- 4.5%, p less than 0.05) and thiobarbituric acid reactive substances (65.8 +/- 18% and 47.2 +/- 17%, p less than 0.05) with respect to the abdominal aorta. The selenium-independent glutathione peroxidase activity was not detectable. In conclusion, a biochemical gradient in glutathione-related antioxidant defences and thiobarbituric acid reactive substances proceeding from the proximal to the distal segments seems to exist in the normal rabbit aorta. These results could contribute to explain the non homogeneous distribution of experimental atherosclerosis in the rabbit aorta.

Animals↗