Effects of a bicarbonate-alkaline mineral water on digestive motility in experimental models of functional and inflammatory gastrointestinal disorders.

This study investigates the effects of Uliveto, a bicarbonate-alkaline mineral water, in experimental models of diarrhea, constipation and colitis. Rats were allowed to drink Uliveto or oligomineral water (control) for 30 days. Diarrhea and constipation were evoked by 16,16-dimethyl-prostaglandin E(2) (dmPGE(2)) or loperamide, respectively. Colitis was induced by 2,4-dinitrobenzenesulfonic acid (DNBS) or acetic acid. Gastric emptying, small-intestinal and colonic transit were evaluated. dmPGE(2)-induced diarrhea reduced gastric emptying and increased small-intestinal and colonic transit. In this setting, Uliveto water enhanced gastric emptying, and this effect was prevented by L-365,260 (gastrin receptor antagonist). Loperamide-induced constipation reduced gastric emptying, small-intestinal and colonic transit, and these effects were prevented by Uliveto water. L-365,260 counteracted the effects of Uliveto on gastric emptying, while alosetron (serotonin 5-HT(3) receptor antagonist) blunted the effect of Uliveto on colonic transit. Gastric emptying, small-intestinal and colonic transit were reduced in DNBS-induced colitis, and Uliveto water enhanced gastric emptying and normalized small-intestinal and colonic transit. Gastric emptying, small-intestinal and colonic transit were also reduced in acetic acid-induced colitis, and Uliveto increased both gastric emptying and small-intestinal transit. In conclusion, Uliveto water exerts beneficial effects on gastrointestinal motility in the presence of bowel motor dysfunctions. The effects of Uliveto water on gastric emptying depend on gastrin-mediated mechanisms, whereas the activation of serotonergic pathways accounts for the modulation of colonic functions.

In vitro studies on gemcitabine combinations with other antiblastics.

The use of gemcitabine in combination with chemotherapeutic agents, including cisplatin, pemetrexed and taxanes, is characterized by the enhancement of their anticancer activity. The analysis of the underlying pharmacodynamics has revealed that modulation of nucleotide pools, drug metabolism, and cellular DNA repair capability are the most common factors to explain the additive to synergistic interaction between gemcitabine and anticancer agents in several human cancers in vitro and in vivo.

Relationship between 5-fluorouracil disposition, toxicity and dihydropyrimidine dehydrogenase activity in cancer patients.

BACKGROUND: Previous work demonstrated that 5-fluorouracil (5-FU) metabolism is a critical factor for treatment tolerability. In order to study the predictivity of pharmacokinetics with respect to the occurrence of 5-FU toxicity, this study investigates the relationship between the pharmacokinetics of 5-FU and its metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU), dihydropyrimidine dehydrogenase (DPD) activity in peripheral blood mononuclear cells (PBMNC) and treatment tolerability. PATIENTS AND METHODS: Pharmacokinetics and metabolism of 5-FU and activity of DPD in PBMNC were examined in 110 colorectal cancer patients given adjuvant 5-FU 370 mg/m2 plus L-folinic acid 100 mg/m2 for five days every four weeks. Drug levels were examined by HPLC. while toxicities were graded according to WHO criteria. RESULTS: DPD activity in patients with mild toxicities (WHO grade < or = 1) was 197.22 < or = 11.34 pmol of 5-FDHU/min/ mg of protein, while in five patients with grade 3-4 gastrointestinal toxicity, DPD ranged from low to normal values (range 31.12-182.37 pmol/min/mg of protein). In these patients. 5-FU clearance (CL) was lower (range 14.12-25.17 l/h/m2), and the area under the curve (AUC) was higher (range 14.70-26.20 h x microg/ml) than those observed in 84 patients with mild toxicities (CL, 56.30 +/- 3.60 l/h/M2; AUC, 7.91 +/- 0.44 h x microg/ml). The severity of adverse events was associated with increased 5-FU/5-FDHU AUC ratio and reduced 5-FU CL, while 5-FU and 5-FDHU pharmacokinetics were not related to DPD activity. CONCLUSION: This study shows that DPD activity in PBMNC is unrelated to 5-FU/5-FDHU disposition and patients with severe toxicity display marked pharmacokinetic alterations while a reduction of DPD activity may not occur.

Comparative pharmacokinetic analysis of 5-fluorouracil and its major metabolite 5-fluoro-5,6-dihydrouracil after conventional and reduced test dose in cancer patients.

The aim of this study was to investigate the clinical pharmacokinetics of 5-fluorouracil (5-FU) and its major metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU) in 20 colorectal cancer patients given two dose levels of 5-FU, 250 and 370 mg/m2, administered by i.v. bolus. A reverse-phase high-performance liquid chromatographic method was used for the simultaneous assay of 5-FU and 5-FDHU in plasma samples obtained at baseline and at multiple time points from 5 min to 4 h after 5-FU bolus as well as to assess the activity of dihydropyrimidine dehydrogenase (DPD) in peripheral blood mononuclear cells (PBMCs) before 5-FU dosing. Plasma pharmacokinetic parameters of patients given 250 mg/m2 5-FU were significantly different from those receiving 370 mg/m2; main differences were observed in the trapezoidal areas under the plasma levels-versus-time curve from to to the last measurable concentration (area under the curve, 3.77+/-0.21 versus 13.61+/-2.3 h x microg/ml), peak plasma concentration (Cmax, 18.15+/-1.35 versus 48.41+/-7.69 microg/ml), and total body clearance (CL(TB), 54.64+/-3.54 versus 25.43+/-2.3 l/h/m2). Significant differences were also observed in the main pharmacokinetic parameters of 5-FDHU after 250 and 370 mg/m2 5-FU including the area under the curve from to to 4 h (5.39+/-0.32 versus 8.75+/-1.24 h x microg/ml), Cmax (3.60+/-0.16 versus 5.26+/-0.55 microg/ml) and time to Cmax (Tmax, 0.45+/-0.03 versus 0.69+/-0.06 h). The mean DPD activity in PBMCs in this group of patients was 205.7+/-36.4 pmol of 5-FDHU/min/mg of protein and was within the normal range; however, no significant correlations were found between 5-FU or 5-FDHU pharmacokinetic parameters at two dose levels and DPD activity of PBMCs. The results of the present study provide the first detailed comparison of the distribution of 5-FU and its major metabolite 5-FDHU at the therapeutic level as well as at reduced test dose levels to obtain pharmacokinetic data to be used as reference values for the identification of patients at risk of major 5-FU toxicity due to impaired metabolism to 5-FDHU.

Infusions of fluorouracil and leucovorin: effects of the timing and semi-intermittency of drug delivery.

Preclinical and clinical studies have demonstrated that the circadian modulation of 5-FU delivery may reduce toxicities and improve antitumor activity. However, the relative importance of the timing of 5-FU delivery has not been clinically addressed. The aims of this study were to determine the toxicities, the maximum tolerable doses and the activity of a regimen with 5-fluorouracil (5-FU) and leucovorin (LV) administered as a 14-day continuous infusion according to a flat or three different chronomodulated rhythms in patients with metastatic gastrointestinal carcinomas. A total of 113 patients entered the study and their characteristics were comparable among the four groups. Toxicities included mainly stomatitis and diarrhea, and a reduced toxicity was observed in all the three chronogroups that allowed the delivery of higher dose intensities. Response rates were not significantly different among the four groups. These results suggest that a reduction in 5-FU+LV toxicity and an increase in 5-FU dose intensity can be obtained by a nonsinusoidally circadian modulated infusion. However, the reduction in toxicity observed seems to be dependent mainly on the quasi-intermittency and not on the timing of 5-FU+LV delivery.

Periodontal tissue disposition of azithromycin in patients affected by chronic inflammatory periodontal diseases.

BACKGROUND: The recognition that periodontal diseases are associated with specific pathogens has led to interest in the use of antibacterial drugs for inhibition of these microorganisms. On these bases, the present study was aimed at evaluating the tissue distribution of the new macrolide antibiotic azithromycin in patients subjected to oral surgery for chronic inflammatory diseases of both marginal and periapical periodontium. METHODS: Thirty-two patients were treated with azithromycin 500 mg/day orally for 3 consecutive days, and drug concentrations in plasma, saliva, normal gingiva, and pathological periodontal tissues were evaluated. For this purpose, samples of blood, saliva, normal gingiva, granulation tissue, and radicular granuloma or cyst wall (from dentigerous cyst) were collected during oral surgery or 0.5, 2.5, 4.5, and 6.5 days after the end of pharmacological treatment; then, azithromycin levels were measured by a microbiological plate assay, using Micrococcus luteus NCTC 8440 as the indicator organism. RESULTS: The concentrations of azithromycin in plasma, saliva, normal gingiva, and pathological tissues reached the highest values 12 hours after the last dose (0.37+/-0.05 mg/l, 2.12+/-0.30 mg/l, 6.30+/-0.68 mg/kg, and 11.60+/-1.50 mg/kg, respectively) and then declined gradually. Consistent levels of the drug in normal gingiva and pathological tissues could be detected, however, up to 6.5 days, indicating that azithromycin was retained in target tissues for a long time after the end of treatment. Moreover, azithromycin levels in both normal gingiva and pathological tissues exceeded the minimum inhibitory concentrations of most pathogens involved in the pathophysiology of chronic inflammatory periodontal diseases. Notably, azithromycin levels in pathological tissues were significantly higher than those in normal gingiva 0.5, 2.5, and 4.5 days after the last dose. CONCLUSIONS: The present results indicate a marked penetration of azithromycin into both normal and pathological periodontal tissues, suggesting that azithromycin represents a promising option in both adjunctive and prophylactic treatments of chronic inflammatory periodontal diseases.

Carbogen and nicotinamide combined with unconventional radiotherapy in glioblastoma multiforme: a new modality treatment.

PURPOSE: A new radiotherapy schedule to treat glioblastoma multiforme after surgery, combining nicotinamide and carbogen. METHODS AND MATERIALS: We analyzed 36 patients with glioblastoma multiforme treated after surgery with radiotherapy, Nicotinamide and Carbogen as follows: 7 patients were treated with accelerated fractionation: two fractions/day, 1.5 cGy/fraction, 6 h interval, 5 days/week, total dose 60 Gy in 4 weeks; 8 patients were treated with the same irradiation scheduling plus Nicotinamide at the dose of 4 g and 2 g in capsules, respectively, 1 h before the first and the second irradiation fraction; 21 patients were treated with accelerated radiotherapy, Nicotinamide, and Carbogen (inhaled 10 min before radiotherapy and during the whole course of irradiation). On the basis of surgical removal our patients were subdivided in three groups: totally resected, with residual tumor <50%, or >50%. Radiotherapy with accelerated fractionation was completed in the scheduled time without side effects on the whole group of patients and Carbogen inhalation did not cause significant change of cardiopulmonar parameters. The toxicity observed was predominant in the gastrointestinal tract and was related to Nicotinamide. RESULTS: The median survival time (M.S.T.) was 10 months, as reported by others authors with conventional treatment, but in patients without surgical residual tumor and submitted to the complete treatment schedule, the survival at 35 months was around 25%. CONCLUSIONS: We conclude that this method is feasible with acceptable toxicity; analyzing the survival curves appears to be a trend towards an improvement in survival in the subgroup of patients with gross total removal treated with the combination of Carbogen, Nicotinamide, and accelerated fractionation.

Protective action of omeprazole against gastric mucosal injury induced by hemorrhagic shock in rats.

The efficacy of omeprazole in preventing gastric mucosal injury induced by hemorrhagic shock in rats and the putative mechanisms involved in this effect were investigated in the present study. Omeprazole did not affect mean arterial blood pressure under both basal conditions and induction of hemorrhagic shock, but it evoked a marked increase in Alcian blue recovery from gastric preepithelial mucus. The morphometric analysis of histological sections revealed that omeprazole caused a significant reduction of hemorrhagic shock-induced damage of gastric mucosa. Ranitidine, used as the reference drug, failed to affect mean arterial blood pressure, Alcian blue recovery from gastric mucus, or hemorrhagic shock-induced damage of gastric mucosa. Both omeprazole and ranitidine exerted a significant inhibition of gastric acid output from anesthetized pylorus-ligated rats. Overall, the present results indicate that omeprazole is effective in protecting gastric mucosa from necrotic damage induced by hemorrhagic shock and suggest that an enhancement of gastric mucus secretion contributes to this protective action.

Macrolide antibiotics as antiinflammatory agents: roxithromycin in an unexpected role.

The antiinflammatory activity of a new 14-membered macrolide antibiotic, roxithromycin, was evaluated in various rat models including carrageenan- and poly-L-arginine-induced hind-paw oedema, croton oil inflamed ear assay and polyester sponge granuloma. When administered orally to animals, roxithromycin displayed an atypical profile in the assays utilized, including: (1) marked antioedema activity similar to that of indomethacin in poly-L-arginine assay, (2) significant inhibition of lambda-carrageenan hind-paw oedema and croton-oil-induced inflammation in the ear, although indomethacin was more effective, and (3) failure to reduce the development of granuloma induced by implanted polyester sponges, while indomethacin significantly reduced the chronic inflammatory reaction. Based on these results, it is concluded that roxithromycin is active in reducing the acute inflammatory reaction in rat models through mechanisms different from conventional nonsteroidal antiinflammatory agents such as indomethacin. Therefore, roxithromycin may have a favorable impact on skin inflammatory reactions accompanying microbial infections.