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Irinotecan is a topoisomerase-I (Top-I) inhibitor used for the treatment of colorectal cancer. DNA demethylating agents, including 5-azacytidine (5-aza), display synergistic antitumor activity with several chemotherapy drugs. 5-Aza may enhance irinotecan cytotoxicity by at least one of the following mechanisms: (a) Top-I promoter demethylation, (b) activation of genes involved in Top-I transcriptional regulation (p16 or Sp1), and (c) modulation of the cell cycle and apoptosis after DNA damage. The growth-inhibitory effects of SN38, the active metabolite of irinotecan, 5-aza, and their combinations, were studied in four colorectal cancer cell lines. The effects of treatments on cell cycle were analyzed by flow cytometry, and apoptosis was measured by fluorescence microscopy. Top-I, Sp1, and p53 expression modulated by 5-aza were measured by real-time PCR. Methylation of Top-I, p16, 14-3-3σ, and hMLH1 promoters before and after 5-aza treatment were measured by MethyLight PCR and DNA bisulfite sequencing. Low-dose 5-aza significantly enhanced the apoptotic effect of irinotecan in all colorectal cancer cells, whereas a synergistic cytotoxic effect was observed only in p53-mutated cells (HT29, SW620, and WiDr). This synergistic effect was significantly correlated with Top-I up-regulation by 5-aza, and coupled to p16 demethylation and Sp1 up-regulation. p16 demethylation was also associated with enhanced cell cycle arrest after irinotecan treatment. In contrast, 5-aza down-regulated Top-I expression in the p53 wild-type LS174T cells in a p53-dependent manner, thereby reducing SN38 cytotoxicity. In conclusion, 5-aza modulates Top-I expression by several mechanisms involving Sp1, p16, and p53. If confirmed in other models, these results suggest that p16 and p53 status affects the 5-aza–irinotecan interaction. [Mol Cancer Ther 2009;8(7):1964–73]

Supplementary Fig. S1 from Epigenetic mechanisms of irinotecan sensitivity in colorectal cancer cell lines

In the past 20 years, an increased discrepancy between new available antibacterials and the emergence of multidrug-resistant strains has been observed. This condition concerns physicians involved in the treatment of central nervous system (CNS) infections, for which clinical and microbiological success depends on the rapid achievement of bactericidal concentrations. In order to accomplish this aim, the choice of drugs is based on their disposition toward the cerebrospinal fluid (CSF), which is influenced by the physicochemical characteristics of antibacterials. A reduced distribution into CSF has been documented for beta-lactams, especially cephalosporins and carbapenems, on the basis of their hydrophilic nature. However, they represent a cornerstone of the majority of combined therapeutic schemes for their ability to achieve bactericidal concentrations, especially in the presence of inflamed meninges. The good tolerability of beta-lactams makes possible high daily dose intensities, which may be associated with increased probability of cure. Furthermore, the adoption of continuous infusion seems to be a fruitful option. Fluoroquinolones, namely moxifloxacin, and antituberculosis drugs, together with the agents such as linezolid, reach the highest CSF/plasma concentration ratio, which is greater than 0.8, and for most of these drugs it is near 1. For all drugs that are currently used for the treatment of CNS infections, the evaluation of pharmacokinetic/pharmacodynamic parameters, on the basis of dosing regimens and their time-dependent or concentration-dependent pattern of bacterial killing, remains an important aspect of clinical investigation and medical practice.

The authors evaluated the influence of 5-fluorouracil (5-FU) on treatment tolerability in 81 colorectal cancer patients given adjuvant 5-FU intravenously plus folinic acid for 6 cycles. The pharmacokinetics of 5-FU and its inactive metabolite 5-fluoro-5,6-dihydrouracil (5-FDHU) were measured on days 1 and 5 of the first chemotherapy cycle, 5 and 45 minutes after bolus administration. 5-FU clearance was significantly lower on day 5 (62.64 ± 20.16 L/h/m(2)) than on day 1 (74.83 ± 31.61 L/h/m(2)). The lower 5-FU clearance values also predicted the side effects during the entire course of chemotherapy. In particular, patients with low clearance values on day 1 had a further reduction in this parameter on day 5, associated with severe toxicities. In conclusion, 5-FU alters its clearance, which could be partly due to a reduction in 5-FDHU biotransformation. These findings have safety implications for poor metabolizers whose drug clearance may fall below the threshold during repeated treatment cycles.

Aims: To demonstrate the synergistic antiproliferative and proapoptotic activity of irinotecan and axitinib in vitro and the improvement of the in vivo effects on angiogenesis and pancreatic cancer. Methods: Proliferation and apoptotic assays were performed on human dermal microvascular endothelial cells and pancreas cancer (MIAPaCa-2, Capan-1) cell lines exposed to SN-38, the active metabolite of irinotecan, axitinib, or their simultaneous combination for 72 hours. ERK1/2 and Akt phosphorylation, the vascular endothelial growth factor (VEGF), VEGF receptor-2, and thrombospondin-1 (TSP-1) concentration were measured by ELISAs. ATP7A and ABCG2 gene expression was performed with real-time polymerase chain reaction and SN-38 intracellular concentrations were measured by high-performance liquid chromatography. Capan-1 xenografts in nude mice were treated with irinotecan and axitinib alone or in simultaneous combination. Results: A strong synergistic effect on antiproliferative and proapoptotic activity was found with the axitinib/SN-38 combination on endothelial and cancer cells. ERK1/2 and Akt phosphorylation were significantly inhibited by lower concentrations of the combined drugs in all the cell lines. Axitinib and SN-38 combined treatment greatly inhibited the expression of the ATP7A and ABCG2 genes in endothelial and cancer cells, increasing the SN-38 intracellular concentration. Moreover, TSP-1 secretion was increased in cells treated with both drugs, whereas VEGFR-2 levels significantly decreased. In vivo administration of the simultaneous combination determined an almost complete regression of tumors and tumor neovascularization. Conclusions: In vitro results show the highly synergistic properties of simultaneous combination of irinotecan and axitinib on endothelial and pancreas cancer cells, suggesting a possible translation of this schedule into the clinics.

This study investigated the expression of A(1) and A(2A) receptors in the rat colonic neuromuscular compartment, and characterized their roles in the control of motility during inflammation. Colitis was induced by 2,4-dinitrobenzenesulfonic acid. A(1), A(2A) receptors, and ecto-5'-nucleotidase (CD73, adenosine producing enzyme) mRNA expression was examined by RT-PCR. The effects of DPCPX (A(1) receptor antagonist), CCPA (A(1) receptor agonist), 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (A(2A) receptor antagonist), 4-[2-[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (A(2A) receptor agonist), AOPCP (CD73 inhibitor) were tested on electrically or carbachol-evoked contractions in colonic longitudinal muscle preparations. In normal colon, RT-PCR revealed the presence of A(1) receptors, A(2A) receptors and CD73, and an increased expression of A(2A) receptors and CD73 was detected in inflamed tissues. In normal colon, DPCPX or 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol enhanced electrically-induced contractions, while in inflamed preparations the effect of DPCPX no longer occurred. In normal colon, CCPA or 4-[2-[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl] benzenepropanoic acid hydrochloride decreased electrically-induced contractions. Under inflammation, 4-[2-[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl] benzenepropanoic acid hydrochloride reduced electrically evoked contractions with higher efficacy, while the inhibition by CCPA remained unchanged. A(1) and A(2A) receptor ligands did not affect carbachol-induced contractions. AOPCP enhanced electrically-induced contractions and prevented the contractile effects of 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol, without interfering with DPCPX, both in normal and inflamed colons. These results indicate that, in normal colon, both A(1) and A(2A) receptors contribute to the inhibitory control of motor functions at neuronal level. Under bowel inflammation, A(1) receptor loses its modulating actions, while the recruitment of A(2A) receptor by CD73-dependent endogenous adenosine drives an enhanced inhibitory control of colonic neuromotility.

A 37-year-old female, who had a neuroendocrine pancreatic neoplasm, underwent duodeno-cephalo-pancreatectomy. In the 2 years following surgery, she had normal levels of serum chromogranin A (CgA), gastrin and other tumor markers. About 3 years after surgery, owing to the onset of reflux-like dyspeptic symptoms, the patient started treatment with the PPI esomeprazole. During PPI treatment, the patient's serum CgA level rose to more than three times the upper limit of normal, although her gastrin levels remained in the normal range. These findings were interpreted as being suggestive of neuroendocrine tumor relapse.Thoraco-abdominal CT, In¹¹¹-octreotide total body scan, CT of sella turcica, Tc(99m)-sestamibi neck scan, mutational analysis of chromosome 11q13 (site of multiple endocrine neoplasia type 1 [MEN1] gene). Discontinuation of, and rechallenge with, esomeprazole.Esomeprazole-induced hyperchromograninemia in the absence of elevated levels of fasting serum gastrin.Discontinuation of acid-suppressive treatment and continuation of oncologic follow-up.

Linezolid is the first oxazolidinone agent introduced into clinical practice for use against Gram-positive bacteria that are resistant to beta-lactams and glycopeptides, including methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). An optimal antibacterial effect is achieved when plasma drug concentrations are above the minimum inhibitory concentration (MIC) [T>MIC] for the entire length of treatment and the ratio between the area under the plasma concentration-time curve (AUC) and the MIC (AUC/MIC) is greater than 100, as is most commonly obtained with administration of the standard dosage of linezolid 600 mg twice daily. A wide tissue distribution, including the CNS and respiratory tract, nearly linear pharmacokinetics and good tolerability are additional characteristics of linezolid. However, variability in the drug pharmacokinetics associated with clinical conditions (e.g. sepsis, burn injuries, end-stage renal disease, cystic fibrosis), haemodialysis and/or young age may lower the T>MIC and the AUC/MIC ratio, thus impairing both antibacterial activity and prevention of mutants. In most cases, changes in the dosage or in the schedule of administration (e.g. an additional [third] daily dose) may improve the effectiveness of linezolid. It is worth noting that linezolid could affect its own metabolism as a result of protein synthesis inhibition in mitochondria, and this could lead to high plasma concentrations and an increased risk of non-negligible toxicities. The latter may be reported during long-term administration of linezolid or in the presence of some pathological conditions (e.g. renal disease or kidney transplantation) associated with high plasma drug concentrations. Therefore, treatment optimization should be considered a requirement for more effective and tolerable use of the drug, particularly in special populations.

Aim: To evaluate the efficacy and safety of the augmentation of clozapine with aripiprazole in patients with treatment-resistant schizoaffective and psychotic bipolar disorders in a retrospective manner. Pharmacodynamic and pharmacokinetic interactions between the two drugs were also investigated. Patients: Three men and 4 women (median age 36 and 40 years, respectively) who had mean scores at BPRS and CGI-Severity of 59.1±12.0 and 5.4±0.5, respectively, were treated with clozapine (mean dose 292.9±220.7 mg/day). Patients received an adjunctive treatment with aripiprazole (mean dose 6.8 ± 3.7 mg/day). Clozapine, norclozapine and aripiprazole plasma levels were measured by means of a high performance liquid chromatograpy with UV detection. Results: Total scores at BPRS decreased significantly (from 59.1±12.0 to 51.1±15.6, p=0.007) after aripirazole augmentation. In particular, the factors “thought disorder” (from 10.4±4.4 to 9.0±4.5, p=.047) and “anergia” (from 10.0±2.7 to 8.0±2.4, p=.018) significantly improved. Concomitant administration of aripiprazole and clozapine did not result in an increase in side effects over the period of treatment. Dose-normalized plasma levels of both clozapine and norclozapine and the clozapine/norclozapine metabolic ratio in all patients did not vary as well. Conclusion: The augmentation of clozapine with aripirazole was safe and effective in severe psychotic schizoaffective and bipolar disorders which failed to respond to atypical antipsychotics. A possible pharmacokinetic interaction between clozapine and aripiprazole does not account for the improved clinical benefit obtained after aripiprazole augmentation.

Since the discovery of two cyclooxygenase isoforms (COX-1, COX-2), efforts have been made to characterize the roles played by these enzymes in the regulation of physiological functions, as well as to explore their involvement in the pathophysiology of inflammatory disorders. In the digestive tract, the majority of evidence has been obtained at mucosal level, where both isoforms regulate various functions, and contribute to the development of inflammatory and neoplastic disorders. The role of COX isoforms in the gut neuromuscular compartment, where their expression has been detected in different species, is still unclear. However, the characterization of actions exerted by COX-derived prostanoids on gut motility has been under investigation for many years, and it is becoming increasingly appreciated that these mediators subserve complex regulatory patterns of COX on digestive motility. More recently, several studies have strengthened the concept that both COX-1 and COX-2 are involved in the modulation of gastrointestinal neuromuscular activity under normal conditions, and that changes in their regulatory activities occur in the presence of various digestive disorders, including inflammatory bowel diseases and postoperative ileus. Despite a large body of preclinical evidence, studies aimed at translating these findings into clinically relevant applications are needed, in an attempt to identify novel therapeutic approaches for treatment of gut disorders associated with motility alterations. This review illustrates and discusses current knowledge of the roles played by COX pathways in the regulation of gastrointestinal neuromuscular functions, both under normal conditions and in the presence of gut disorders.

Metronomic chemotherapy (the frequent, long term, low dose administration of chemotherapeutic drugs) is a promising therapy because it enhances the anti-endothelial activity of conventional chemotherapeutics, but with lower or no toxic effects compared to maximum tolerated dose administration. The aims of the present study were to compare, in vitro and in vivo, the antiangiogenic and antitumor activities of metronomic irinotecan (CPT-11), oxaliplatin (L-OHP) and 5-fluorouracil (5-FU) in colorectal cancer and to investigate the metronomic combination of these drugs. In vitro cell proliferation, combination studies and vascular endothelial growth factor (VEGF) secretion analyses were performed on endothelial (HMVEC-d) and colorectal cancer (HT-29) cells exposed for 144 h to metronomic concentrations of SN-38, the active metabolite of CPT-11, L-OHP and 5-FU. HT-29 human colorectal cancer xenograft model was used and tumour growth, microvessel density and VEGF quantification were performed in tumours after the administration of metronomic CPT-11, L-OHP, 5-FU and their simultaneous combination. Low concentrations of SN-38, but not 5-FU and L-OHP, preferentially inhibited endothelial cell proliferation. Simultaneous and continuous exposure of HT-29 and HMVEC-d cells to low concentrations SN-38+L-OHP+5-FU for 144 h showed a strong antagonism and an unfavorable dose-reduction index. Moreover, the ternary combination resulted in a significant increase of VEGF secretion in HT-29 cancer cells. In a xenograft model metronomic CPT-11, but not 5-FU and L-OHP, significantly inhibits HT-29 tumor growth and microvessel density in the absence of toxicity. On the contrary, metronomic 5-FU+L-OHP+CPT-11 therapy did not affect the microvascular count. The metronomic concept might not universally apply to every cytotoxic drug in colorectal cancer and metronomic combination regimens should be used with caution.

Purpose: The aims of the present study were to evaluate the clinical activity and the pharmacodynamic profile of the novel schedule of a single i.v. standard dose of cyclophosphamide (CTX) immediately followed by an oral metronomic CTX regimen with celecoxib (CXB) and dexamethasone (DEX) in advanced hormone-refractory prostate cancer patients. Experimental Design: Twenty-eight patients (68% docetaxel-resistant) received 500 mg/m2 CTX i.v. bolus on day 1 and, from day 2, 50 mg/day CTX p.o. plus 200 mg/twice a day CXB p.o. and 1 mg/day DEX p.o. until disease progression. Plasma vascular endothelial growth factor (VEGF) and thrombospondin-1 were detected by ELISA, and real-time reverse transcription-PCR of VEGF and thrombospondin-1 gene expression on peripheral blood mononuclear cell and of VE-cadherin (VE-C) in blood samples was done. Results: A confirmed prostate-specific antigen decrease of ≥50% from baseline was observed in 9 of 28 patients (32%). Median progression-free survival and overall survival were 3 months (95% confidence interval, 2.2-4.2 months) and 21 months (95% confidence interval, 12.4-29.4 months), respectively. Toxicity was mild and no grade 3 to 4 toxicities occurred. A significant relationship was found between plasma VEGF and prostate-specific antigen values (r = 0.4223; P < 0.001). VEGF levels significantly increased in nonresponders, whereas the responder patients maintained significantly lower levels of VE-C gene expression after the beginning of the treatment if compared with nonresponder ones. Conclusion: Metronomic CTX plus CXB and DEX showed favorable toxicity and activity profile in patients. VE-C gene expression and VEGF levels represent potentially useful pharmacodynamic markers for the clinical response.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Generic medicinal products are ‘copies’ of patented drugs and can be marketed at low cost following patent expiration of the brand-name preparations. • Although the development of generic medicinal products is regulated by specific guidelines, a number of issues and concerns continue to undermine the confidence of physicians and patients in generic drugs. WHAT THIS STUDY ADDS • The present findings open interesting perspectives for the discussion of the quality of generic drugs in the postmarketing setting. • In particular, our trial shows that postmarketing evaluation of bioequivalence between branded amoxicillin and its generic copies might result in lack of interchangeability. AIMS There are concerns about the quality of generic drugs in the postmarketing setting. The aim was to establish whether two generic formulations of amoxicillin, available on the Italian market, fulfil the criteria for clinical pharmacokinetic bioequivalence vs. the branded drug. METHODS Two generic amoxicillin products (generic A and B) were selected among four fast-release tablet formulations available on the Italian market. Twenty-four healthy adult volunteers of either sex participated to a single-dose, randomized, three-treatment, crossover, single-blind bioequivalence study designed to compare generic A and B with branded amoxicillin. Plasma samples were collected at preset times for 24 h after dosing, and assayed for amoxicillin levels by high-performance liquid chromatography. RESULTS Ninety percent confidence intervals of AUC ratios were 0.8238, 1.0502 (ratio 0.9302) and 0.8116, 1.1007 (ratio 0.9452) for generic A and B vs. branded amoxicillin, respectively. Ninety percent confidence intervals of Cmax ratios were 0.7921, 1.0134 (ratio 0.8960) and 0.8246, 1.1199 (ratio 0.9610) for generic A and B vs. branded amoxicillin, respectively. The mean pharmacokinetic profiles showed that the AUC value of branded amoxicillin was 8.5 and 5.4% greater than that estimated for generic A and B, respectively. Few adverse events were recorded; these were not serious and occurred without apparent relationship to any specific amoxicillin formulation. CONCLUSIONS These results indicate that one of the two marketed amoxicillin generics analysed in the present study is not bioequivalent to the brand leader product for Cmax on the basis of single-dose pharmacokinetic assessment.

Endometriosis is a chronic, multifactorial, polygenic gynecological disease. Endometrium has a high angiogenic potential and endometriotic lesions involve large areas with a rich blood supply. Angiogenesis is controlled by numerous inducers, including the vascular endothelial growth factor (VEGF) family. Endometrium undergoes cyclical growth and regression during the menstrual cycle, which depends on ovarian steroid levels and is a rich source of angiogenic growth factors, including VEGF-A. The VEGF-A gene is located on chromosome 6p21.3 and it is highly polymorphic with more than 20 different variants. This article critically reviews the published data concerning the relationships between some of the VEGF-A single nucleotide polymorphisms and the risk, pathogenesis and stage of endometriosis. Contrasting results have been published in the literature - probably due to the different ethnic background and the number of patients enrolled in clinical trials. However, the increasing interest in the use of antiangiogenic drugs (eg anti-VEGF-A drugs) in the therapy of endometriosis may suggest carrying out further genetic and pharmacogenetic studies of this disease because the stratification of patients at risk of endometriosis can lead to early diagnosis and optimal treatment choice.

A number of pyrazolo[3,4-d]pyrimidin-4-ones bearing either alkyl or arylalkyl substituents in position 2 of the nucleus were synthesized and tested for their ability to inhibit adenosine deaminase (ADA) from bovine spleen. The 2-arylalkyl derivatives exhibited excellent inhibitory activity, showing Ki values in the nanomolar/subnanomolar range. The most active compound, 1-(4-((4-oxo-4,5-dihydropyrazolo[3,4-d]pyrimidin-2-yl)methyl)phenyl)-3-(4-(trifluoromethyl)phenyl)urea, 14d, was tested in rats with colitis induced by 2,4-dinitrobenzenesulfonic acid to assess its efficacy to attenuate bowel inflammation. The treatment with 14d induced a significant amelioration of both systemic and intestinal inflammatory alterations in animals with experimental colitis. Docking simulations of the synthesized compounds into the ADA catalytic site were also performed to rationalize the structure−activity relationships observed and to highlight the key pharmacophoric elements of these products, thus prospectively guiding the design of novel ADA inhibitors.

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed drugs due to their high efficacy in the treatment of pain, fever, inflammation and rheumatic disorders. However, their use is associated with the occurrence of adverse effects at the level of digestive tract, ranging from dyspeptic symptoms, gastrointestinal erosions and peptic ulcers to more serious complications, such as overt bleeding or perforation. To overcome problems related to NSAID-induced digestive toxicity, different therapeutic strategies can presently be considered, including the co-administration of drugs endowed with protective activity on the upper gastrointestinal tract, such as the proton pump inhibitors, or the prescription of coxibs, which have been clinically developed as anti-inflammatory/analgesic drugs characterized by reduced damaging activity on gastrointestinal mucosa. The availability of different treatment options, to reduce the risk of NSAID-induced adverse digestive effects, has fostered intensive preclinical and clinical research aimed at addressing a number of unresolved issues and to establish rational criteria for an appropriate use of coxibs in the medical practice. Particular attention is being paid to the management of patients with high degrees of digestive risk, resulting by concomitant treatment with low-dose aspirin for anti-thrombotic prophylaxis or ongoing symptomatic gastroduodenal ulcers. The present review discusses the most relevant lines of evidence concerning the position of coxibs in the therapeutic strategies for gastrointestinal protection in patients who require NSAID therapy and hold different levels of risk of developing adverse effects at the level of digestive tract.

Background : There is ongoing debate about the safety of selective serotonin reuptake inhibitors (SSRIs) and other serotonergic/noradrenergic antidepressants when used during pregnancy. Objective : This article reviews the available literature on the main safety concerns associated with the use of SSRIs and other serotonergic/noradrenergic antidepressants (serotonin—norepinephrine reuptake inhibitors, norepinephrine reuptake inhibitors, noradrenergic and specific serotonergic antidepressants) during pregnancy. Methods : English-language reports of analytical and descriptive studies, including case reports, case series, and meta-analyses, were identified through searches of MEDLINE, EMBASE, and PsycINFO (1966–April 2009). The search terms were fluoxetine, paroxetine, sertraline, Citalopram, escitalopram, fluvoxamine, venlafaxine, mirtazapine, reboxetine, duloxetine, SSRI, SNRI, NaSSA , and NRI in association with depression, pregnancy, prenatal exposure, miscarriage, spontaneous abortion, malformation, in utero exposure , and neonatal complications . Results : Paroxetine has been associated with significant risks of major malformation, particularly cardiac defects, when used during pregnancy. Significant associations between maternal exposure to SSRIs and both persistent pulmonary hypertension of the newborn and a self-limiting neonatal behavioral syndrome have been reported in a number of recent original studies and meta-analyses. Some studies have suggested a relationship between the use of SSRIs or other serotonergic/noradrenergic antidepressants and the occurrence of miscarriage, although these studies had methodologic limitations that affected the strength of the data. Evidence for a possible association between in utero exposure to SSRIs or other serotonergic/noradrenergic antidepressants and alterations in neurobehavioral development, bleeding, and QTc-interval prolongation is currently weak. Conclusion : The available evidence suggests that SSRIs and other serotonergic/noradrenergic antide-pressants should be used with caution during pregnancy, with careful follow-up of infants exposed to these agents in utero.

Irinotecan is a topoisomerase-I (Top-I) inhibitor used for the treatment of colorectal cancer. DNA demethylating agents, including 5-azacytidine (5-aza), display synergistic antitumor activity with several chemotherapy drugs. 5-Aza may enhance irinotecan cytotoxicity by at least one of the following mechanisms: (a) Top-I promoter demethylation, (b) activation of genes involved in Top-I transcriptional regulation (p16 or Sp1), and (c) modulation of the cell cycle and apoptosis after DNA damage. The growth-inhibitory effects of SN38, the active metabolite of irinotecan, 5-aza, and their combinations, were studied in four colorectal cancer cell lines. The effects of treatments on cell cycle were analyzed by flow cytometry, and apoptosis was measured by fluorescence microscopy. Top-I, Sp1, and p53 expression modulated by 5-aza were measured by real-time PCR. Methylation of Top-I, p16, 14-3-3σ, and hMLH1 promoters before and after 5-aza treatment were measured by MethyLight PCR and DNA bisulfite sequencing. Low-dose 5-aza significantly enhanced the apoptotic effect of irinotecan in all colorectal cancer cells, whereas a synergistic cytotoxic effect was observed only in p53-mutated cells (HT29, SW620, and WiDr). This synergistic effect was significantly correlated with Top-I up-regulation by 5-aza, and coupled to p16 demethylation and Sp1 up-regulation. p16 demethylation was also associated with enhanced cell cycle arrest after irinotecan treatment. In contrast, 5-aza down-regulated Top-I expression in the p53 wild-type LS174T cells in a p53-dependent manner, thereby reducing SN38 cytotoxicity. In conclusion, 5-aza modulates Top-I expression by several mechanisms involving Sp1, p16, and p53. If confirmed in other models, these results suggest that p16 and p53 status affects the 5-aza–irinotecan interaction. [Mol Cancer Ther 2009;8(7):1964–73]

Objective: To report and discuss a case of rhabdomyolysis in an elderly patient with neuropathic pain who was treated with gabapentin. Case Summary: An 85-year-old diabetic woman was hospitalized for severe pain in her lower limbs and difficulty in walking, compromising her daily activities. On admission, the woman's laboratory parameters, including creatine kinase (CK) and myoglobin, were in the normal range. Neurologic evaluation suggested a diagnosis of diabetic neuropathic pain, and therapy with gabapentin 150 mg 3 times daily was started. On the same day, the patient developed psychomotor agitation and gastric pain, which were treated with haloperidol 10 mg and lansoprazole 30 mg, respectively. In the following hours, the severity of muscular pain increased and the patient developed myopathy with acute renal failure (CK 459 U/L, myoglobin 11 437 ng/mL, creatinine 4.59 mg/dL), which worsened progressively during the next 2 days (CK 3095 U/L, myoglobin 17 000 mg/dL, creatinine 4.77 mg/dL) despite discontinuation of haloperidol and lansoprazole. No signs of trauma or edema, suggesting possible compartmental or crush syndrome, were detected. Gabapentin was then withdrawn and the patient's condition rapidly improved. Complete recovery followed in about 10 days. Discussion: Severe myopathy is an unexpected adverse reaction to gabapentin therapy. In this patient, a possible contribution of haloperidol or lansoprazole to the adverse event cannot be excluded. However, worsening of the clinical picture despite discontinuation of these drugs, together with rapid improvement observed after withdrawal of gabapentin, strongly suggest a causative role of gabapentin. According to the Naranjo probability scale, gabapentin was the probable cause of myopathy in this patient. The mechanism by which gabapentin may induce myopathy is unknown. The early onset of the syndrome after initiation of treatment with gabapentin in therapeutic doses is compatible with the picture of an idiosyncratic adverse response. Conclusions: Pathogenetic and clinical investigations are required to explore what mechanisms account for gabapentin-related muscular alterations at the time of onset, including electromyographic recordings as well as muscle and nerve histopathologic examinations. Until more information is available, clinicians should consider the possibility of discontinuing gabapentin treatment in patients showing muscular pain and signs of myopathy.

Cholecystokinin and related peptides are involved in the control of intestinal motility and cholecystokinin receptor ligands might represent new pharmacological tools for the treatment of symptoms associated with functional bowel disorders. However, the respective roles played by cholecystokinin receptor subtypes and the mechanisms underlying these regulatory actions remain undetermined. This study was designed to examine the influence of cholecystokinin receptor subtypes on the motor activity of guinea-pig distal colon. The effects of drugs acting on CCK1 and CCK2 receptors were assessed in vitro on the contractile activity of longitudinal smooth muscle, both under basal conditions and in the presence of transmural electrical stimulation or KCl-induced contractions. The application of cholecystokinin octapeptide sulphate (cholecystokinin-8S) to colonic preparations induced concentration-dependent contractions which were prevented by devazepide (CCK1 receptor antagonist), enhanced by GV150013 (CCK2 receptor antagonist) or N(omega)-nitro-L-arginine methylester (L-NAME, nitric oxide synthase inhibitor), and unaffected by tetrodotoxin. The application of gastrin-17 to colonic preparations resulted in relaxant responses which were insensitive to devazepide, and prevented by GV150013, L-NAME or tetrodotoxin. L-NAME, N(omega)-propyl-L-arginine (NPA, neuronal nitric oxide synthase inhibitor) or GV150013 enhanced electrically evoked contractile responses, whereas devazepide did not. When tested in the presence of L-NAME or NPA the enhancing effect of GV150013 on electrically induced contractions no longer occurred. In the presence of KCl-induced pre-contractions, cholecystokinin-8S or gastrin-17 evoked concentration-dependent relaxations, which were unaffected by devazepide and were counteracted by GV150013, L-NAME, NPA or tetrodotoxin. In conclusion, the present results indicate that, at level of distal colon, CCK1 receptors mediate direct contractile effects on smooth muscle, whereas CCK2 receptors on enteric neurons mediate relaxant responses via nitric oxide release.

Purpose: Standard treatments have modest effect against pancreatic cancer, and current research focuses on agents targeting molecular pathways involved in tumor growth and angiogenesis. This study investigated the interactions between ZD6474, an inhibitor of tyrosine kinase activities of vascular endothelial growth factor receptor-2 and epidermal growth factor receptor (EGFR), gemcitabine, and ionizing radiation in human pancreatic cancer cells and analyzed the molecular mechanisms underlying this combination.Experimental Design: ZD6474, ionizing radiation, and gemcitabine, alone or in combination, were given in vitro to MIA PaCa-2, PANC-1, and Capan-1 cells and in vivo to MIA PaCa-2 tumor xenografts. The effects of treatments were studied by the evaluation of cytotoxicity, apoptosis, cell cycle, EGFR and Akt phosphorylation, modulation of gene expression of enzymes related to gemcitabine activity (deoxycytidine kinase and ribonucleotide reductase), as well as vascular endothelial growth factor immunohistochemistry and microvessel count.Results: In vitro, ZD6474 dose dependently inhibited cell growth, induced apoptosis, and synergistically enhanced the cytotoxic activity of gemcitabine and ionizing radiation. Moreover, ZD6474 inhibited phosphorylation of EGFR and Akt and triggered cell apoptosis. PCR analysis showed that ZD6474 increased the ratio between gene expression of deoxycytidine kinase and ribonucleotide reductase. In vivo, ZD6474 showed significant antitumor activity alone and in combination with radiotherapy and gemcitabine, and the combination of all three modalities enhanced MIA PaCA-2 tumor growth inhibition compared with gemcitabine alone.Conclusions: ZD6474 decreases EGFR and Akt phosphorylation, enhances apoptosis, favorably modulates gene expression in cancer cells, and acts synergistically with gemcitabine and radiotherapy to inhibit tumor growth. These findings support the investigation of this combination in the clinical setting.

Background and Objectives Dihydropyrimidine dehydrogenase (DPD) plays a key role in the catabolism of 5-fluorouracil (5-FU) to 5-fluoro-5,6-dihydrouracil (5-FDHU), and as such, an impairment of DPD has been recognized as an important factor for altered 5-FU and 5-FDHU pharmacokinetics, predisposing patients to the development of severe 5-FU-associated toxicity. Our objectives were to avoid severe 5-FU toxicities in patients with greatly impaired 5-FU and 5-FDHU pharmacokinetics after the administration of a reduced test dose of 5-FU and to investigate possible 5-FU or 5-FDHU pharmacokinetic parameters of the test dose related to the most common drug toxicities that affect patients after the first cycle of 5-FU chemotherapy. Methods Pharmacokinetics of 5-FU/5-FDHU and DPD activity in peripheral blood mononuclear cells (PBMCs) were examined in 188 gastrointestinal cancer patients given a test dose of 5-FU, 250 mg/m2, 2 weeks before starting the planned 5-FU treatment of 370 mg/m2 plus L-folinic acid, 100 mg/m2, for 5 days every 4 weeks. Drug levels were examined by HPLC, and toxicities were graded according to World Health Organization criteria. Results The 5-FU test dose was well tolerated in all patients. Of 188 patients, 3 (1.6%) had marked alterations of 5-FU/5-FDHU pharmacokinetics (ie, 5-FU half-life [t½β] >5 hours, 5-FU total body clearance [CLTB]

Purpose: Recent clinical studies have demonstrated a reduction of irinotecan (CPT-11) gastrointestinal toxicities when the CPT-11 is administered in combination with thalidomide in patients with diagnosis of colorectal cancer. The main purpose of this study was to investigate possible interactions between CPT-11 pharmacokinetics and thalidomide to explain the previously described gastrointestinal toxicity reduction. Methods: In our clinical trial, advanced cancer patients were treated with CPT-11 on a dose of 350 mg/m2 at day 1 every 3 weeks. Only at the first cycle, CPT-11 was administered in association with thalidomide on a dose of 400 mg/day given from day 1 to day 14. From the second cycle, the treatment was continued with irinotecan alone at the same dose. Pharmacokinetics analysis of irinotecan and its metabolites, SN-38 and SN-38-glucuronide, were performed at the first and second cycle. Results: A total of 19 patients entered the study. The pharmacokinetic analysis were performed on 16 patients. Pharmacokinetic data suggested a decreased metabolism of irinotecan into SN-38 and SN-38-glucuronide when it was administered with thalidomide. Indeed, area under the time–concentration curve (AUC) of SN-38 was significantly lower at the first cycle than the second cycle (0.99±0.45 h×μg/ml vs 1.34±0.65, respectively, P=0.027) whereas AUC of irinotecan and SN-38-glucuronide were higher at first cycle than second cycle (34.53±11.38 h×µg/ml vs. 28.42±12.23 h×µg/ml, P=0.064 and 2.39±1.21 h(μg/ml vs. 1.86±1.11 h×μg/ml, P=0.018, respectively). Conclusions: Our study demonstrates a significant decreased metabolism of CPT-11 into the active metabolite SN-38 when CPT-11 is administered in association with thalidomide. These observations strongly suggest an interaction of thalidomide with CPT-11 metabolism and, at least in part, it might explain the previously described improvement in tolerability.

The efficacy and safety of basiliximab, in combination with different maintenance regimens, are extensively addressed in the available literature. Basiliximab reduces the incidence of acute rejection, allows a safe reduction of steroid dosage, and is associated with economic savings, although there is substantially no proof that basiliximab prolongs either patient or graft survival. Initial basiliximab administration entails a low-risk and is associated with fewer adverse events than T cell depleting agents. However, life-threatening reactions were reported following re-exposure to basiliximab in recipients who lost graft function early after transplantation and, therefore, discontinued all immunosuppressive agents.

This study investigated the effect of acute liver damage on the inactivation of 5-fluorouracil (5-FU) to its main catabolite 5-fluoro-5,6-dihydrouracil (5-FUH2) in mice. Plasma pharmacokinetics of 5-FU and 5-FUH2 in mice receiving 5-FU (10, 30, and 90 mg/kg) were compared to those in mice pretreated with carbon tetrachloride and receiving the same 5-FU doses. Carbon tetrachloride-induced hepatic damage was histopathologically examined under light microscopy and serum transaminases and dihydropyrimidine dehydrogenase activities were also measured. Liver histopathology and elevated aminotransferase activity levels confirmed the presence of liver damage. 5-FU C(max) and AUC both increased up to 71% in mice with liver damage. This was reflected by decreased 5-FUH2 production, since 5-FUH2 C(max) and AUC levels decreased up to 47% and 61%, respectively. Metabolic ratios between 5-FUH2 and 5-FU AUCs were considerably decreased as well, further suggesting that liver damage caused a reduction in 5-FU catabolism. DPD activity was not altered in damaged livers. The present results indicate that 5-FU disposition in mice could be profoundly altered in the presence of severe liver impairment, potentially leading to enhanced anabolic activation of 5-FU. This effect seems to be ascribed to a reduction of viable hepatocytes, rather than to an inactivation of DPD activity.

The association omeprazole/clarithromycin is of current wide use in the treatment of Helicobacter pylori associated gastroduodenal ulcer. This combination may result in increased levels of omeprazole with potential interactions with commonly associated drugs. Kinetic/metabolic changes occurring after omeprazole/clarithromycin were compared to those occurring after pantoprazole/clarithromycin in healthy volunteers. Eight healthy volunteers, all males, age 25-34 years, all EM for CYP2C19, participated in a randomized, double blind crossover study in two periods of 7 days, separated by a 14-day washout. In each treatment period, subjects took either omeprazole 20mg b.i.d. together with clarithromycin 500 mg b.i.d., or pantoprazole 40 mg b.i.d. with the same dose of the antibiotic. The pharmacokinetic parameters of omeprazole and pantoprazole were compared to those after intake of both agents alone. Kinetics of unchanged clarithromycin was evaluated at the end of the two periods. The mean value of the area under the plasma concentration versus time curve (AUC) of unchanged omeprazole increased almost two-fold after concomitant administration of clarithromycin; the average 5-OH-omeprazole AUC was instead significantly reduced by 42%. Omeprazole clearance and volume of distribution were reduced significantly by 75 and 56%, respectively, after administration of the drug with clarithromicyn. No significant changes of the kinetic of pantoprazole and metabolites were observed. Kinetics of clarithromycin did not differ after the two associated treatments. The administration of clarithromycin with two different proton pump inhibitors indicates that the antibiotic can markedly increase omeprazole, not pantoprazole, levels. This observation may result in a better therapeutic response to omeprazole, but it may also potentially affect either the metabolism of CYP3A4 substrates or interfere with the absorption of drugs requiring an intact gastric digestion system.

Drug therapeutic failure (DTF) could be considered as an adverse drug reaction in which the expected drug effects do not occur following a prescribed pharmacological treatment, including any clinical event that could be related to a low prescribed dose or lack of compliance. DTFs are responsible for increasing disease length, hospitalisation time and social costs, with the worsening of patient quality of life. The aims of the present study are: (1) to estimate the frequency of DTFs among cases of adverse drug events referred to the emergency department; (2) to identify drug classes implicated in DTFs; (3) to analyse the putative causes underlying DTFs. Data presented in this paper were obtained from the Pronto Soccorso and Adverse Drug Events (PSADE) study carried out to analyse drug-related emergency department admissions in several Italian hospitals. Patients, admitted to the emergency department throughout two periods of 10 days each, were interviewed to gain information on their medical status and drug intake during the last two weeks. The present study analysed the patient questionnaires collected in the emergency department of Pisa University Hospital. Among 123 recorded cases of adverse drug event, 41 cases (19:22 male:female ratio; age range: 17-98 years, median age: 75 years) were identified as suspect DTF, resulting in a frequency of 33.33%. A statistical analysis was performed to evaluate the influence of two variables, class of patient age and number of drugs assumed, on DTFs. In accordance with the present findings, showing that the number of drugs assumed by a patient may increase the risk of DTF more than advanced age (odds ratio: 1.371, P0.02; 1.295, P0.03, respectively), the prescription of pharmacological combinations might be proposed as a main risk factor for DTF occurrence. In conclusion, our results suggest that DTFs represent an important cause of emergency department admission, particularly in elderly subjects treated with pharmacological associations.

Serotonin reuptake is mediated by a transporter protein (SERT), and its dysfunctions can alter serotonergic transmission. The present study examines the binding profile of platelet SERT in healthy volunteers as well as in patients with diarrhea-predominant irritable bowel syndrome (D-IBS), both before and after treatment with the 5-HT(3) receptor antagonist alosetron.Binding of [(3)H]paroxetine to SERT was assayed in platelet membranes collected from D-IBS patients (12 women, age 21-73 yr) and healthy volunteers (12 women, age 24-68 yr). Both maximal binding capacity (B(max)) and dissociation constant (K(d)) were estimated. In D-IBS patients, binding parameters and symptom severity score were evaluated at baseline and after treatment with alosetron (1 mg b.i.d. for 8 wk).At baseline, B(max) and K(d) values of [(3)H]paroxetine binding were respectively lower and higher in D-IBS patients than in healthy volunteers (B(max): 518.7 +/- 155.9 vs 1151.9 +/- 187.4 fmol/mg, p0.001; K(d): 0.19 +/- 0.05 vs 0.06 +/- 0.02 nmol/L, p0.001). Symptom severity score in D-IBS patients (50.9 +/- 18.8) was negatively correlated with B(max) (r = -0.964; p0.001) but not K(d) values (r = -0.164; p = 0.609). After treatment with alosetron, symptom severity score decreased significantly (14.4 +/- 3.7; p0.001), whereas B(max) (522.7 +/- 39.7 fmol/mg) and K(d) values (0.17 +/- 0.07 nmol/L) did not change.The present results indicate that SERT expressed on platelet membranes of D-IBS patients is characterized by low density and binding affinity and suggest a possible correlation between the reduced capacity of serotonin reuptake and the severity of D-IBS symptoms.

Invasive mycoses are associated with a high mortality rate, and their incidence is increased in immunologically deficient patients. From a diagnostic and therapeutic perspective, these infections represent a significant challenge to medicine. In addition to new antifungal agents, drug combinations are an important therapeutic resource, which might be exploited clinically, owing to the multiplicity of fungal targets against which currently available agents are active. In this review, we examine the experimental data regarding the combination of conventional antifungal agents with cytokines, antibacterial agents, calcineurin inhibitors and drugs under development characterized by novel mechanisms of action.

This study investigates the influence of intestinal inflammation on: (1) the control of intestinal neurotransmission and motility by prejunctional α2-adrenoceptors and (2) the expression of intestinal α2-adrenoceptors. Experimental colitis was induced by intrarectal administration of 2,4-dinitrobenzenesulphonic acid (DNBS) to rats. UK-14,304 inhibited atropine-sensitive electrically evoked contractions of ileal and colonic longitudinal muscle preparations. UK-14,304 acted with similar potency, but higher efficacy, on tissues from DNBS-treated animals; its effects were antagonized with greater potency by phentolamine than rauwolscine. Electrically induced [3H]noradrenaline release from ileal preparations was reduced in the presence of colitis. Tritium outflow was decreased by UK-14,304 and stimulated by rauwolscine or phentolamine: these effects were enhanced in preparations from animals with colitis. Reverse transcription–polymerase chain reaction and Western blot assay demonstrated the protein expression of α2A-adrenoceptors in mucosal and muscular tissues isolated from ileum and colon. The induction of colitis increased α2A-adrenoceptor expression in both ileal and colonic muscular layers, without concomitant changes in mucosal tissues. Induction of colitis reduced gastrointestinal propulsion of a charcoal suspension in vivo. In this setting, the gastrointestinal transit was inhibited by intraperitoneal (i.p.) UK-14,304 and stimulated by i.p. rauwolscine. After pretreatment with guanethidine, the stimulant action of rauwolscine no longer occurred, and UK-14,304 exerted a more prominent inhibitory effect that was antagonized by rauwolscine. The present results indicate that, in the presence of intestinal inflammation, prejunctional α2-adrenoceptors contribute to an enhanced inhibitory control of cholinergic and noradrenergic transmission both at inflamed and noninflamed distant sites. Evidence was obtained that such modulatory actions depend on an increased expression of α2A-adrenoceptors within the enteric nervous system. Keywords: α2-Adrenoceptors, acetylcholine, noradrenaline, enteric nervous system, intestinal motility, intestinal inflammation Introduction The gastrointestinal tract is extensively innervated by extrinsic noradrenergic neurons, whose projections end in close proximity to several cellular targets (i.e. epithelial cells, neurons, blood vessels). Locally, through their interaction with α2-adrenoceptors, endogenous catecholamines modulate a variety of digestive functions, including secretions and motility (Del Tacca et al., 1982; De Ponti et al., 1996; Liu & Coupar, 1997), gastro-colonic sensation (Malcom et al., 2000), and epithelial cell proliferation (Schaak et al., 2000). Both sympathetic and cholinergic axon terminals of the enteric nervous system are equipped with prejunctional α2-adrenoceptors, the activation of which inhibits noradrenaline and acetylcholine release, respectively (Blandizzi et al., 1993; Funk et al., 1995; Colucci et al., 1998). Inflammatory diseases of the human gut (e.g. inflammatory bowel disease, coeliac disease, infectious gastroenteritis) are commonly associated with alterations of enteric functions, including increased secretion and motor abnormalities, which are thought to contribute to the generation of digestive symptoms (Collins, 1996, Giaroni et al., 1999; Sharkey & Kroese, 2001). For this reason, there is currently great interest in understanding the pathophysiological changes occurring in the enteric nervous system as a consequence of intestinal inflammation (Sharkey & Kroese, 2001). Such alterations occur throughout the gut, at both inflamed and noninflamed sites, and they depend, at least in part, on mutual interactions between enteric nerves and the digestive immune system (Collins, 1996). The role played by adrenoceptors in intestinal inflammation remains poorly understood. Experimental colitis in rats was associated with downregulation of β3-adrenoceptors in colonic circular smooth muscle (Zhao et al., 2001). An increased density of α2-adrenergic binding sites was detected in cell membrane preparations obtained from jejunal tissues of guinea-pigs with small bowel inflammation (Martinolle et al., 1993). However, data on the possible influence exerted by prejunctional α2-adrenoceptors on enteric neurotransmission and digestive motility in the presence of intestinal inflammation are lacking. Accordingly, the present study was designed to assess the influence of experimentally induced intestinal inflammation on: (1) the control of enteric neurotransmission and intestinal motility by prejunctional α2-adrenoceptors and (2) the expression pattern of intestinal α2-adrenoceptors.

In mammalian cells, the process of malignant transformation is characterized by the loss or down-regulation of tumor-suppressor genes and/or the mutation or overexpression of proto-oncogenes, whose products promote dysregulated proliferation of cells and extend their life span. Deregulation in intracellular transduction pathways generates mitogenic signals that promote abnormal cell growth and the acquisition of an undifferentiated phenotype. Genetic abnormalities in cancer have been widely studied to identify those factors predictive of tumor progression, survival, and response to chemotherapeutic agents. Pharmacogenetics has been founded as a science to examine the genetic basis of interindividual variation in drug metabolism, drug targets, and transporters, which result in differences in the efficacy and safety of many therapeutic agents. The traditional pharmacogenetic approach relies on studying sequence variations in candidate genes suspected of affecting drug response. However, these studies have yielded contradictory results because of the small number of molecular determinants of drug response examined, and in several cases this approach was revealed to be reductionistic. This limitation is now being overcome by the use of novel techniques, i.e., high-density DNA and protein arrays, which allow genome- and proteome-wide tumor profiling. Pharmacogenomics represents the natural evolution of pharmacogenetics since it addresses, on a genome-wide basis, the effect of the sum of genetic variants on drug responses of individuals. Development of pharmacogenomics as a new field has accelerated the progress in drug discovery by the identification of novel therapeutic targets by expression profiling at the genomic or proteomic levels. In addition to this, pharmacogenetics and pharmacogenomics provide an important opportunity to select patients who may benefit from the administration of specific agents that best match the genetic profile of the disease, thus allowing maximum activity.

Objectives: The administration of antibacterial agents should be optimized on the basis of their distribution to enhance drug exposure and obtain bacterial eradication. This study examines the pharmacokinetics of azithromycin in plasma, lung tissue and bronchial washing in patients after oral administration of 500 mg versus 1000 mg once daily for 3 days. Patients and methods: Samples of plasma, lung tissue and bronchial washing were obtained from a cohort of 48 patients during open-chest surgery for lung resection up to 204 h after the last drug dose, and assayed for antibiotic concentrations. Results: Azithromycin was widely distributed within the lower respiratory tract and sustained levels of the drug were detectable at the last sampling time in lung tissue. Doubling the dose of the antibiotic resulted in a proportional increase in lung area under the curve (AUC, 1245.4 versus 2514.2 h × mg/kg) and peak tissue concentration (C max , 8.93 ± 2.05 versus 18.6 ± 2.20 mg/kg). The pharmacodynamic parameter AUC/MIC for susceptible and intermediate strains of Strepto- coccus pneumoniae (MICs 0.5 and 2 mg/L, respectively) increased after administration of the 1000 mg schedule compared with 500 mg (AUC/MIC 0.5 2414 versus 1144 and AUC/MIC 2 2112 versus 814.1 h × mg/kg, respectively) in pulmonary tissue. Conclusions: Lung exposure to azithromycin is increased proportionally by doubling the dose, which results in a predictable pharmacokinetic behaviour of the drug in the lower respiratory tract.

) model.Finally, the influence of paclitaxel and Cremophor EL on epirubicin metabolism bywhole blood was examined.Results An increase in epirubicinol plasma concentrations occurred after the start ofthe paclitaxel infusion, resulting in a significant increase in the area under the plasmaconcentration-time curve (AUC) of epirubicinol (+0.5

Background The anticancer drug irinotecan induces cholinergic side effects that are currently ascribed to the blockade of acetylcholinesterase. This study investigated (1) the pattern of acetylcholinesterase activity in patients receiving treatment with irinotecan and (2) the relationship between acetylcholinesterase activity and plasma concentrations of irinotecan, 7-ethyl-10-hydroxycamptothecin (SN-38), and SN-38 glucuronide (SN-38G). Methods Twenty-five patients with advanced colorectal cancer were treated with 250 mg/m2 irinotecan administered by intravenous infusion for 60 minutes. Blood samples were collected before drug infusion and at 15 minutes and 45 minutes after the start of drug infusion. Blood acetylcholinesterase activity was determined by a colorimetric enzymatic assay, and irinotecan, SN-38, and SN-38G concentrations were determined in plasma by HPLC. The in vitro effects of irinotecan and other drugs on human acetylcholinesterase were also assessed. Results Compared with basal values, the activity of acetylcholinesterase in blood specimens collected during irinotecan infusion at 15 minutes (−0.76%) and at 45 minutes (−1.50%) showed no changes. No relationships were established between the activity of blood acetylcholinesterase at 15 or 45 minutes and plasma concentrations of irinotecan, SN-38, or SN-38G measured at the same time points. In vitro, the activity of acetylcholinesterase was inhibited by 100-μmol/L irinotecan (−24.8%) and markedly reduced by 1-μmol/L physostigmine (−86.7%), whereas neither SN-38 nor camptothecin had an effect. Conclusions Although the use of erythrocyte acetylcholinesterase as a surrogate marker of acetylcholinesterase activity in the nervous system has not been firmly established, our findings do not support the hypothesis that the toxic cholinergic syndrome associated with irinotecan treatment depends on acetylcholinesterase blockade. Clinical Pharmacology & Therapeutics (2002) 71, 263–271; doi: 10.1067/mcp.2002.121909

The increased incidence of invasive mycoses and the emerging problem of antifungal drug resistance has prompted investigations of the underlying molecular mechanisms, particularly for the azole compounds central to current therapy. The target site for the azoles is the ERG11 gene product, the cytochrome P450 lanosterol 14alpha-demethylase, which is part of the ergosterol biosynthetic pathway. The resulting ergosterol depletion renders fungal cells vulnerable to further membrane damage. Development of azole resistance in fungi may occur through increased levels of the cellular target, upregulation of genes controlling drug efflux, alterations in sterol synthesis and decreased affinity of azoles for the cellular target. Here, we review the adaptative changes in fungi, in particular Candida albicans, in response to inhibitors of ergosterol biosynthesis. The molecular mechanisms of azole resistance might help in devising more effective antifungal therapies.

This study investigates the mechanisms that account for the adverse cardiovascular effects of the antitumor drug irinotecan. The activities of irinotecan, its active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38), and camptothecin were assayed in urethane-anesthetized rats to determine their effects on heart rate and blood pressure. In vitro experiments were performed to assess the effects of test drugs on acetylcholinesterase activity. Intravenous irinotecan (10 micromol/kg) decreased heart rate and blood pressure, but SN-38, camptothecin, or intracerebroventricular irinotecan had no effect. The bradycardic and hypotensive responses induced by irinotecan were abolished by bilateral vagotomy or atropine. Physostigmine caused a transient bradycardia, followed by a tachycardic response, and promoted a marked increment of blood pressure. Vagotomy or atropine prevented the bradycardic action of physostigmine, whereas the tachycardic and hypertensive responses were sensitive to atropine, but not to vagotomy. Five minutes after irinotecan administration (10 micromol/kg i.v.), its concentration in plasma and atrial tissue accounted for 2.29 +/- 0.19 micromol/L and 1.08 +/- 0.16 micromol/kg, respectively. The in vitro activity of human erythrocyte acetylcholinesterase was significantly inhibited by irinotecan (-21.5% at 100 microM) or physostigmine (-84.8% at 1 microM), whereas SN-38 or camptothecin had no effect. Rat atrial acetylcholinesterase was also significantly inhibited in vitro by irinotecan (-16.9% at 100 microM). The present results indicate that irinotecan exerts depressant effects on both heart rate and arterial blood pressure. A direct activation of cholinergic receptors or an interaction with central nervous sites does not appear to account for these inhibitory actions, whereas a blockade of acetylcholinesterase seems to occur at concentrations of irinotecan that may not be relevant in clinical settings.

The evaluation of mucosal damage in experimental models of gastric injury is commonly based on macroscopic detection of gross lesions and/or histological examination of tissue samples and is limited by the subjectivity of the examiner and by the paucity of nonrepresentative samples. This study proposes a novel method for the histomorphometric analysis of gastric damage, based on the examination of seriate parallel strips taken from whole rat stomachs. Strips were cut perpendicular to the lesser curvature, placed on a glass slide, with the side of each strip distal to the pylorus upward, and processed for routine histology. Sections were then observed by light microscopy: the length of damaged mucosa divided by the total length of mucosa, measured on a micrometric scale and expressed in percentage values, was indicated as the lesion index. Furthermore, to evaluate the severity of the damage, three types of lesions were discriminated depending on their depth: type I, lysis of luminal cells; type II, damage involving the cells lying on both surface mucosa and gastric pits; and type III, damage involving the lower part of the lamina propria with injury of glands associated with detachment of whole mucosal layers. Three models of acute gastric damage (ethanol, hemorrhagic shock, and indomethacin) were examined and treatment was also carried out with the antiulcer drugs omeprazole, ranitidine, and misoprostol, to show the advantages of this histomorphometric approach. The results indicate that this method allows an accurate quantitative analysis of gastric damage, and the effects of different antiulcer drugs can be better discriminated.

The use of immunosuppressive agents in the treatment of transplant rejection and autoimmune disorders is gaining momentum, with significant improvements of both graft and patient survival. The individual response to drugs, however, is variable and unexpected toxicity, or impaired activity might be seen, as a result of molecular determinants that eventually dictate how the individual will respond to immunosuppressive agents. This review addresses a number of issues related to pharmacogenetics, and discusses how this approach might be used to improve the clinical efficacy and tolerability of therapeutic options for the management of organ transplantation and autoimmune disorders in the next decade.

1. The present study investigates whether presynaptic histamine receptors regulate noradrenaline release from intestinal sympathetic nerves. The experiments were performed on longitudinal muscle-myenteric plexus preparations of guinea-pig ileum, preincubated with [(3)H]-noradrenaline. 2. In the presence of rauwolscine, electrically-induced [(3)H]-noradrenaline release was inhibited by histamine or R-alpha-methylhistamine, whereas it was unaffected by pyridylethylamine, impromidine, pyrilamine, cimetidine, thioperamide or clobenpropit. The inhibitory effects of histamine or R-alpha-methylhistamine were antagonized by thioperamide or clobenpropit, but not by pyrilamine or cimetidine. In the absence of rauwolscine, none of these drugs modified the release of [(3)H]-noradrenaline. 3. The modulatory action of histamine was attenuated by pertussis toxin and abolished by N-ethylmaleimide. Tetraethylammonium or 4-aminopyridine enhanced the evoked tritium outflow and counteracted the inhibitory effect of histamine. However, the blocking effects of tetraethylammonium and 4-aminopyridine were no longer evident when their enhancing actions were compensated by reduction of Ca(2+) concentration in the superfusion medium. 4. Histamine-induced inhibition of tritium output was enhanced by omega-conotoxin or low Ca(2+) concentration, whereas it was not modified by nifedipine, forskolin, rolipram, phorbol myristate acetate, H7 or lavendustin A. 5. The present results indicate that presynaptic H(3) receptors, located on sympathetic nerve endings, mediate an inhibitory control on intestinal noradrenergic neurotransmission. It is suggested that these receptors are coupled to G(i)/G(o) proteins which modulate the activity of N-type Ca(2+) channels through a direct link, thus reducing the availability of extracellular Ca(2+) at the level of noradrenergic nerve terminals.

The present study investigated (1) the pharmacological profile of cholecystokinin (CCK) receptor subtypes involved in the regulation of gastric pepsinogen secretion, (2) the influence of gastric acidity on peptic responses induced by CCK-8-sulfate (CCK-8S) or gastrin-I; and (3) the mechanisms accounting for the effects of CCK-like peptides on pepsinogen secretion. In anaesthetized rats, i.v. injection of CCK-8S or gastrin-I increased both pepsinogen and acid secretion. The pepsigogue effect of CCK-8S was higher than that of gastrin-I, whereas acid hypersecretion after CCK-8S was lower than that induced by gastrin-I. Peptic output following CCK-8S was partly blocked by i.v. injection of the CCK1 receptor antagonist, devazepide (-75.3%), or the CCK2 receptor antagonist, L-365,260 [3R(+)-N-(2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepine-3 yl)-N'-(3-methyl-phenyl)urea; -27.9%], but was fully prevented by combined administration of devazepide and L-365,260. The gastric acid hypersecretory effect of CCK-8S was enhanced by devazepide (+84.5%) and blocked by L-365,260. In contrast, the gastric secretory actions of gastrin-I were insensitive to devazepide, but abolished by L-365,260. Excitatory effects of CCK-8S and gastrin-I were not modified by vagotomy or atropine, whereas cimetidine or alpha-fluoromethylhistidine (irreversible blocker of histidine decarboxylase) partly prevented acid hypersecretion induced by both peptides without affecting their pepsigogue effects. After pretreatment with omeprazole, both CCK-8S and gastrin-I failed to stimulate acid secretion, while they increased pepsinogen output. In rats with gastric perfusion of acid solutions, CCK-8S or gastrin-I increased peptic output in a pH-independent manner either with or without pretreatment with omeprazole. Ablation of capsaicin-sensitive sensory nerves as well as application of lidocaine to the gastric mucosa failed to modify the excitatory effects of CCK-8S or gastrin-I on pepsinogen and acid secretion. Blockade of the nitric oxide (NO) synthase pathway by N(G)-nitro-L-arginine-methyl ester prevented the pepsigogue actions of both CCK-8S and gastrin-I (-61.8% and -71.7%, respectively), without affecting the concomitant increase in acid output. In addition, both these peptides significantly increased the release of NO breakdown products into the gastric lumen. The present results suggest that: (1) both CCK1 and CCK2 receptors mediate the peptic secretory responses induced by CCK-like peptides; (2) the excitatory inputs of CCK-8S and gastrin-I to chief cells are not driven through acid-dependent mechanisms or capsaicin-sensitive afferent sensory nerves; and (3) under in vivo conditions, the stimulant actions of CCK-like peptides on pepsinogen secretion are mediated, at least in part, by an increase in NO generation.

The gastric mucosal distribution of azithromycin, the prototype of a new class of macrolide antibiotics named azalides, was studied in patients with duodenal ulcer and Helicobacter pylori-related gastritis. The time course of ulcer healing, H. pylori infection, and gastritis activity was also evaluated. Twenty patients (median age 50 years) received the following treatment for 1 month: three cycles of azithromycin (500 mg/day for 3 consecutive days) on days 1-3, 11-13 and 21-23 plus omeprazole (40 mg/day) for 30 consecutive days. Endoscopic biopsy specimens of gastric mucosa and blood samples were collected on days 0, 4, 7, 10, 20 and 30. An additional follow-up endoscopy was carried out on day 60. H. pylori infection was determined by both histology and rapid urease test. Azithromycin concentrations in both plasma and gastric mucosa were measured by a microbiological plate assay, using Micrococcus luteus NCTC 8440 as the reference organism. Azithromycin concentrations in plasma ranged between 0.17 mg/L (95% CI: 0.08-0.26; n = 5) and 0.32 mg/L (95% CI: 0.21-0.43; n = 5) throughout the treatment period. In addition, azithromycin concentrations in gastric mucosa were significantly higher than plasma concentrations at all times examined and ranged from 18.5 mg/kg (95% CI: 15-20; n = 20) to 24.6 mg/kg (95% CI: 16.8-32.4; n = 5), Indicating that the drug was highly retained in the target tissue. Accordingly, the ratio of azithromycin mucosal level to plasma concentration varied between 77.9 (95% CI: 56.5-99.3; n = 5) and 112.7 (95% CI: 100.2-125.2; n = 5). At the end of treatment (day 30) H. pylori was no longer detected in 16 of 20 patients (80%), and this finding was consistent with a marked decrease in the grading of gastritis activity. At the follow-up endoscopy (day 60) the infection was eradicated in only four patients (20%). These data indicate a favourable distribution of azithromycin into gastric mucosa of patients with H. pylori infection and suggest that this new macrolide antibiotic represents a valuable option for treatment regimens against H. pylori. However, the low eradication rate achieved with azithromycin plus omeprazole is a source of concern and requires further investigation.

4-Methylpyrazole (4-MP), a specific inhibitor ofalcohol dehydrogenase, exerts gastroprotection ofunusually long duration in rats. We tested thehypothesis that pretreatment with 4-MP might protect the human gastric mucosa against alcohol-inducedacute injury. Fourteen healthy volunteers receivedpretreatment with either 4-MP, 15 mg/kg body weightdissolved in 50 ml of orange juice, or placebo and 2 hr later 100 ml of 40% ethanol. The endoscopicappearance of the gastric mucosa was evaluated andscored (scale 0-5) and mucosal biopsies were obtainedjust before pretreatment and 30 min after ethanol for histologic examination and prostaglandinE2 measurement. In the 4-MP group the meanendoscopic injury score was significantly lower thanthat in placebo group, in both the body and the antrum.Histologically, 4-MP significantly reduced disruption ofsurface epithelium and completely prevented the deephemorrhagic mucosal lesions. In the 4-MP group nochanges in gastric mucosal PGE2 levels weredetected. In rats, 4-MP did not inhibit gastric acid output,whereas it markedly increased the adherent gastric mucusevaluated by the alcian blue recovery method. When lipidperoxidation was induced by carbon tetrachloride in hepatic microsomes, 4-MP caused significantinhibition of malondialdehyde generation. We concludethat 4-MP provides significant protection of the humanstomach against alcohol-induced acute mucosal injury. 4-MP, besides inhibiting the conversionof alcohol to acetaldehyde, might protect the gastricmucosa by increasing adherent gastric mucus and byscavenging free radicals.

The tissue penetration of azithromycin, the prototype of a new class of macrolide antibiotics named azalides, was studied in patients undergoing surgery for third-molar removal. Drug concentrations in plasma, saliva, and periodontal tissues were evaluated in 28 patients treated with azithromycin 500 mg/day per os for 3 consecutive days. Samples of blood, saliva, gingiva, and alveolar bone were collected during oral surgery, 12 hours, and 2.5, 4.5, and 6.5 days after the last dosing, and the azithromycin concentration was measured microbiologically by using Micrococcus luteus NCTC 8440 as the reference organism. The highest concentrations of azithromycin were observed 12 hours after the last dose in plasma, saliva, gingiva, and bone (0.33 +/- 0.04 mg/l, 2.14 +/- 0.30 mg/l, 6.47 +/- 0.57 mg/kg, and 1.86 +/- 0.15 mg/kg, respectively) and then declined gradually. However, consistent levels of the drug in saliva and periodontal tissues could be detected up to 6.5 days, indicating that azithromycin was retained in target tissues and fluids for a long time after the end of treatment. Among the samples examined, the highest concentration of azithromycin was found in the gingiva at each time studied. Moreover, the ratios of salivary or periodontal tissue levels versus plasma concentrations remained nearly unmodified from 12 hours up to 6.5 days. Overall, these results indicate a favorable disposition of azithromycin into saliva and periodontal tissues and suggest that this macrolide antibiotic represents a valuable option in the pharmacologic treatment of odontogenic infections.

Mario Del Tacca,1,2 Giuseppe Pasqualetti,3 Giovanni Gori,1 Pasquale Pepe,1 Antonello Di Paolo,2 Marianna Lastella,2 Ferdinando De Negri,1 Corrado Blandizzi2 1Clinical Pharmacology Centre for Drug Experimentation, Pisa University Hospital, 2Department of Clinical and Experimental Medicine, 3Geriatrics Unit, University of Pisa, Pisa, Italy Purpose: The primary aim of the present study was to assess the pharmacokinetic bioequivalence between a generic formulation of meloxicam 15 mg tablets (Meloxicam Hexal) and its respective brand product (Mobic), in order to verify whether the generic product conforms to the regulatory standards of bioequivalence in the postmarketing setting. As a secondary exploratory aim, the pharmacodynamic effects of the two formulations were also evaluated by means of rating scales following hyperalgesia induced by cutaneous freeze injury. Subjects and methods: A single 15 mg dose of generic or branded meloxicam tablets was administered to 24 healthy male volunteers in a crossover fashion. Plasma samples, collected for 24 hours after dosing, were assayed for meloxicam concentration by a validated high-performance liquid chromatography method. Results: The analysis of pharmacokinetic parameters did not show any significant difference between the two meloxicam formulations: the 90% confidence intervals fell within the acceptance range of 80%–125% (0.84–1.16 for area under the curve [0–24], and 0.89–1.23 for peak concentration). No difference in the pharmacodynamic end point was observed between the two groups. Conclusion: The pharmacokinetic profiles of the two meloxicam formulations confirm the regulatory criteria for bioequivalence; pharmacodynamic data indicate a similar antihyperalgesic effect. The two formulations can be used interchangeably in the clinical setting. Keywords: meloxicam, pharmacokinetics, healthy volunteers, generic drug, bioequivalence, postmarketing A Letter to the Editor has been received and published for this article.

The pharmacokinetic properties of nicotinamide and its tolerance were studied in seven patients affected by glioblastoma multiforme and treated with two fractions per day of radiation therapy. Nicotinamide was given orally at two daily doses of 4 g and then 2 g separated by a 6-h-interval. The treatment was well tolerated in almost all patients and had no effect on blood pressure, cardiac rhythm or body temperature. Pharmacokinetic analysis showed peak plasma levels (Cmax) above 100 mg/l 45 minutes after the administration of both doses. This was followed by a biexponential decay of plasma concentrations with a thermal half life of 9.4 h. Tumours were irradiated 1 hour after each drug dose to match with drug Cmax in plasma, and although it is too early to evaluate the tumour response, the drug levels achieved should be sufficient to improve radiation therapy.

Azithromycin concentrations in the tonsils of 56 pediatric patients, treated with 10 or 20 mg of the drug per kg of body weight for 3 days, were compared. Azithromycin levels in plasma and tonsil samples were determined up to 8.5 days after the last dose. The 20-mg/kg regimen resulted in an improved tonsillar distribution of azithromycin, suggesting the achievement of enhanced therapeutic concentrations at infective sites of the upper respiratory tract.

Drug development is a complex process that includes drug discovery/product development, pre-clinical research (in vitro/in vivo) and clinical trials. The new chemical entities, which show promising pharmacodynamic activity in in vitro experiments on particular biological targets, thought to play critical pathophysiological roles in specific diseases, emerge from the process of drug discovery and are candidates to undergo safety and toxicity tests, as well as pharmacokinetic and metabolism evaluations in in vivo preclinical models. Moreover, pre-clinical investigations are focused on determining the dose and administration schedule to be used in the first human clinical trial (first-in-man or first human dosing). Clinical drug development is currently arranged into four phases, with phase I traditionally representing the very early stage of drug development in humans. Phase I is conducted to establish safety and tolerability, to evaluate pharmacokinetics and to obtain preliminary data on pharmacodynamics. Phase I begins with the first administration of a new compound in humans (Pocock, 1983). Based on differences in the experimental design, various types of phase I trials can be distinguished: (1) Single ascending dose studies, in which small groups of subjects receive a single dose of the test drug, afterward they are observed and examined for a given period of time. If subjects do not experience any remarkable adverse effect, and pharmacokinetic data are roughly consistent with pre-specified safety values, the dose is escalated up, and a new group of subjects is then given a higher dose (Buoen et al., 2005). This stepping-up dose is continued until the pre-calculated pharmacokinetic safety levels are achieved, or intolerable side effects occur, indicating the point at which the drug appears to have reached the maximum tolerated dose (Friedman et al., 1996). The first dose to be tested in phase I is estimated as a fraction of the so called “no adverse effect dose”, which is the highest dose found not to harm animals under appropriate toxicity/safety testing. (2) Multiple ascending dose studies, characterized by an experimental design similar to single ascending dose studies, with the exception that, at each step, a small group of subjects undergoes repeated administration of the same dose of the test drug. Such studies can be conducted to better understand the pharmacokinetics and pharmacodynamics of the new drug at the steady state. (3) Short trials, designed to investigate variations in the absorption of the new drug following its oral administration in the presence of food.