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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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Linezolid is effective against methicillin-resistant Staphylococcus aureus, which may cause central nervous system (CNS) infections, but drug concentrations in plasma are characterized by a large inter-patient variability. Therefore, the present study was aimed at evaluating linezolid pharmacokinetics in plasma and cerebrospinal fluid (CSF) in 7 patients with external ventricular drainage, who received linezolid 600 mg twice daily as 1-h intravenous infusion to prevent CNS infections.Plasma and CSF linezolid concentrations were measured by high-performance liquid chromatography (HPLC) after the 1(st) and 5(th) dose, and pharmacokinetics were evaluated by non-compartmental analysis.Values of the CSF area under the time/concentration curve (AUC) (range 18.2-85.5 and 19.6-160.5 h × mg/l at the 1st and 5th dose, respectively) were lower than those calculated in plasma (range 27.6-224.0 and 27.5-166.1 h × mg/l, respectively). For minimum inhibitory concentration (MIC) = 1 mg/l, CSF AUC/MIC values were nearly equal to or greater than 100 only in 2 subjects after the 1st and 5th dose, whereas mean time above the MIC (TMIC) values were higher than 75% in only 3 patients. Similar results were obtained when pharmacokinetic/pharmacodynamic parameters were evaluated in plasma.The present results suggest that changes in linezolid doses and measurement of drug concentrations should be considered as useful strategies to optimize treatment in some patients.

CYTOTOXIC immunosuppressive agents have a longstanding important role in pharmacological immunosuppression. Azathioprine was among the first immunosuppressive drugs used in organ transplantation, and further development in this field was landmarked by the introduction of ALKYLATING AGENTS (i.e., cyclophosphamide) and ANTIMETABOLITES (i.e., fludarabine, METHOTREXATE and mycophenolic acid) in therapeutic regimens for the prevention of graft rejection (see chapter C12) and the treatment of AUTOIMMUNE DISEASES (see chapter C15) because of their well-documented lymphocytolytic effect.

Introduction Lung cancer is one of the most lethal tumors and, although standard chemotherapy produces clinical response, there has been little improvement in prognosis. Therefore, research effort has focused on target-specific agents, such as sorafenib, which blocks both the RAF/MEK/ERK signalling pathways and receptors involved in neovascularization and tumor progression, including VEGFR-2 and c-Kit. We investigated whether sorafenib would be synergistic with gemcitabine against NSCLC cell lines. Materials and methods Human lung cancer cells A549, CALU-1, CALU-6, H23 and HCC 827 were treated with sorafenib and gemcitabine, alone or in combination, and the cytotoxicity was assessed with CellTiter 96 Non-radioactive cell proliferation kit. Cell cycle and apoptosis were investigated with flow cytometry and fluorescence microscopy, respectively. Moreover, the effects of drugs on Akt (S473), c-Kit (Y823) and ERK (pTpY185/187) phosphorylation were studied with ELISA. Finally, quantitative PCR analysis was performed to assess whether sorafenib and gemcitabine modulated the expression of genes related to drug activity. Results Gemcitabine and sorafenib synergistically interacted on the inhibition of cell proliferation, and assessment of apoptosis demonstrated that drug associations increased the apoptotic index. Sorafenib reduced c-Kit and ERK activation and gemcitabine inhibited Akt phosphorylation. Moreover quantitative PCR showed that sorafenib modulated the expression of targets related to gemcitabine activity, while gemcitabine induced the expression of RKIP. Conclusions These data demonstrate that sorafenib and gemcitabine synergistically interact against NSCLC cells, through suppression of Akt, c-Kit and ERK phosphorylation, induction of apoptosis and modulation of dCK, RRM1, RRM2 and RKIP gene expression. The association between traditional cytotoxic agents with new target-specific agents, such as sorafenib, is a challenge for both clinical and preclinical future investigations in lung cancer treatments.

Daptomycin and linezolid, recently introduced to treat severe Gram-positive infections, are effective against multidrug-resistant Gram-positive microorganisms such as methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, and vancomycin-resistant Enterococci bacteria that are less sensitive or frankly resistant, including methicillin-resistant S. aureus. However, alteration of their plasma profile has been described in some patients and this may be associated with toxicities or selection of resistant strains. The measurement of plasma concentrations of both drugs may allow the identification of those subjects at major risk of adverse events. Therefore, a rapid and sensitive high-performance liquid chromatography method for the analysis of daptomycin and linezolid was developed and applied in clinical settings. Drugs were extracted from plasma by adding methanol and, after centrifugation, clear supernatants were injected into the high-performance liquid chromatography system. Isocratic elution (1.5 mL/min) was performed using a mobile phase consisting of ammonium phosphate buffer 40 mM, pH 4.0, acetonitrile (70:30, vol/vol) through a BDS C8 Hypersil stationary phase (250 x 4.6 mm, 5 mum); ultraviolet detection was used at 214 nm. Linezolid and daptomycin eluted within 20 minutes from the injection, and mean recoveries ranged between 95.4% and 112.1%, respectively. The method was linear (coefficient of linearity, 0.998-0.999) over the full range of concentrations assayed, from 0.78125 mg/L (limit of quantitation) to 100 mg/L for both drugs. The Sy.x values were equal to 0.25 +/- 0.10 and 0.29 +/- 0.18 mg/L for daptomycin and linezolid, respectively. Precision values were lower than 20% over the entire range of calibration standard, and accuracy was within the range of 80% to 120% for all concentrations. The present method proved to be sensitive and specific to measure daptomycin and linezolid plasma concentrations in patients affected by severe Gram-positive infections, allowing therapeutic drug monitoring in those patients at major risk of severe adverse events.

Purpose: Oxaliplatin effect in the treatment of colorectal cancer is improved upon combination with thymidylate synthase (TS) inhibitors. Pemetrexed is polyglutamated by the folylpolyglutamate synthase (FPGS) and blocks folate metabolism and DNA synthesis by inhibiting TS, dihydrofolate reductase (DHFR) and glycinamide ribonucleotide formyltransferase (GARFT). The present study evaluates the pharmacological interaction between oxaliplatin and pemetrexed in colorectal cancer cells. Methods: Human HT29, WiDr, SW620 and LS174T cells were treated with oxaliplatin and pemetrexed. Drug interaction was studied using the combination index method, while cell cycle was investigated with flow cytometry. The effects of drugs on Akt phosphorylation and apoptosis were studied with ELISA and fluorescence microscopy, respectively. RT-PCR analysis was performed to assess whether drugs modulated the expression of pemetrexed targets and of genes involved in DNA repair (ERCC1 and ERCC2). Finally, platinum–DNA adduct levels were detected by ultra-sensitive multi-collector inductively coupled plasma mass spectrometry (ICP-MS). Results: A dose-dependent inhibition of cell growth was observed after drug exposure, while a synergistic interaction was detected preferentially with sequential combinations. Oxaliplatin enhanced cellular population in the S-phase. Drug combinations increased apoptotic indices with respect to single agents, and both drugs inhibited Akt phosphorylation. RT-PCR analysis showed a correlation between the FPGS/(TS × DHFR × GARFT) ratio and pemetrexed sensitivity, as well as a downregulation of ERCC1, ERCC2, TS, DHFR and GARFT after drug exposure. In addition, pretreatment with pemetrexed resulted in an increase of oxaliplatin–DNA adducts. Conclusion: These data demonstrate that oxaliplatin and pemetrexed synergistically interact against colon cancer cells, through modulation of cell cycle, inhibition of Akt phosphorylation, induction of apoptosis and modulation of gene expression.

Gemcitabine (2',2'-difluorodeoxycytidine) (GEM) is one of the most actively investigated drugs in ovarian cancer. Many molecular mechanisms have been proposed to be involved in GEM sensitivity/resistance including the equilibrative nucleoside transporter-1 (hENT1), the concentrative nucleoside transporter-1 (hCNT1), and deoxycytidine kinase (dCK). The expression of the ribonucleotide reductase regulatory subunits M1 (RRM1) and M2 (RRM2), and the catabolic enzymes 5'nucleotidase (5'NT), and cytidine deaminase (CDA) play also an important role. The aim of the study is to investigate the potential clinical role of hENT1, hCNT1, dCK, RRM1, RRM2, CDA, and 5'NT in a single institutional series of 25 primary ovarian carcinomas.The expression levels of the target genes were assayed by means of real-time quantitative PCR. The clinical role of the expression levels of each parameter was analyzed by Kaplan and Meier method and the Cox's proportional hazards model.hENT1, hCNT1, dCK, CDA, 5'NT, RRM1, and RRM2 gene expression was documented in all samples; undifferentiated and clear cell carcinoma exhibited higher levels of hENT1, dCK, 5'NT, and RRM1 compared to serous ovarian tumors. As of May 2009, the median follow-up was 32 months (range 10-80), and death of disease were observed in 17 cases (68.0%). A statistically significant direct association of RRM2 expression levels and the relative risk of death was observed (Chi (2) = 8.18, P = 0.0043). Moreover, cases with high RRM2 expression had a shorter OS (median OS = 19 months) than cases with low RRM2 levels (median OS = 36 months) (P = 0.0506).We first reported that the most relevant genes involved in gemcitabine metabolism are expressed in ovarian carcinoma, and might be associated with more aggressive histotypes. The assessment of the expression levels of RRM2 as marker of clinical outcome deserves further investigation in a larger series of ovarian cancer patients.

The main goal of early phase trials is to gain knowledge about the clinical suitability of novel compounds, without pursuing specific therapeutic purposes. Healthy volunteers usually represent the ideal model for conducting phase I clinical trials, in order to investigate pharmacokinetics and pharmacodynamics as well as to document safety and tolerability without interference by concomitant pathological conditions. The increasing cost of novel drug development, in conjunction with ethical considerations, has fostered a new procedure for first-in-man trials, designated as "phase 0," which is conducted very early on a limited number of healthy volunteers who are exposed to low drug levels. The present review discusses issues concerning the enrollment of healthy volunteers in the early phase of drug development from different points of view, with some focus on the Italian experience. From the ethical standpoint, much discussion revolves around payments to healthy volunteers. Most authors agree that an adequate remuneration must be provided to healthy subjects, while avoiding coercion and excessive psychological pressure. Pending the lack of international and national guidelines, our center for clinical drug experimentation has implemented an operative procedure to estimate payments for healthy volunteers based on specific items, including restriction, time spent, discomfort, and risk. Other unresolved issues about the recruitment of healthy volunteers are represented by the lack of international consensus on the definition of healthy status and the need for guidelines about advertisement on clinical trials addressed to potential participants.

Background: Current treatments have a modest impact on survival of pancreatic cancer patients and this study investigates the interaction between sorafenib and gemcitabine and the molecular pharmacodynamics of this combination. Methods: The pancreatic cancer cells were treated with sorafenib and gemcitabine, alone or in combination. The effects of treatments were evaluated on cell proliferation, cell cycle, apoptosis, phosphorylation of Akt, c-Kit, ERK and VEGFR2, and expression of genes related to drug activity. Results: Gemcitabine and sorafenib synergistically interacted on the inhibition of cell proliferation, and assessment of apoptosis demonstrated that drug associations increased the apoptotic index. Sorafenib reduced c-Kit, ERK and VEGFR2 activation and on the other hand, gemcitabine inhibited Akt phosphorylation. Moreover, quantitative PCR showed that sorafenib modulated the expression of genes related to gemcitabine activity, while gemcitabine induced the expression of RKIP. Conclusion: These data demonstrate that gemcitabine and sorafenib combination displays a synergistic effect in pancreatic cancer cells.

Recent data reported an association between VEGF-A genotype of tumors and median overall survival as well as grade 3 or 4 hypertension when using bevacizumab in metastatic breast cancer. In the present case we report a discordant VEGF-A genotype between tumor and normal tissue in a patient with a responsive hepatic lesion of chemoresistant breast cancer treated with bevacizumab and paclitaxel. Moreover, we show that, despite the very low VEGF-A protein expression, the neoplastic lesion was well vascularized and responded to bevacizumab therapy. The discordance of VEGF-A polymorphisms in tumor and germline DNA may suggest the importance of obtaining both information in order to predict a superior overall survival or a lower risk of hypertension in patients treated with taxanes and bevacizumab.

Aims: ABCB1 is a transmembrane transporter that is expressed in excretory organs (kidneys and liver), in intestine mucosa and on the blood–brain barrier. Because of the particular distribution of the protein, the activity of ABCB1 may significantly affect drug pharmacokinetics during absorption and distribution. Of note, several SNPs of ABCB1 are known and many of them affect transporter activity and/or expression. In this view, changes in the pharmacokinetics of drugs that are ABCB1 substrates could be clinically relevant and the evaluation of ABCB1 SNPs should deserve particular attention. Therefore, the aim of the present study was to investigate the possible association between ABCB1 polymorphisms and clozapine plasma levels in psychotic patients. Materials & methods: c.1236C>T (exon 12), c.2677G>T (exon 21) and c.3435C>T (exon 26) SNPs of ABCB1 were evaluated by PCR techniques, while plasma levels of clozapine and norclozapine were measured by HPLC in 40 men (aged, 47.6 ± 16.6 years, median: 42 years) and 20 women (aged 40.7 ± 11.4 years, median: 38 years) 1 month after the start of clozapine administration. Results: A total of three SNPs were in Hardy–Weinberg equilibrium, with a calculated frequency of the wild-type alleles of 0.54, 0.55 and 0.45 for SNPs on exons 12, 21 and 26, respectively. Patients with c.3435CC or c.2677GG genotypes had significantly lower dose-normalized clozapine levels than those who were heterozygous or TT carriers. More interestingly, c.3435CC patients (15 subjects) needed significantly higher daily doses of clozapine (246 ± 142 mg/day) compared with the remaining 24 CT and 21 TT patients (140 ± 90 mg/day) in order to achieve the same clinical benefit. Conclusion: c.3435CC patients require higher clozapine doses to achieve the same plasma concentrations as CT or TT patients, and ABCB1 genotyping should be considered as a novel strategy that should improve drug use.

5-Fluorouracil (5-FU) is a cornerstone in the treatment of many cancers, including colorectal, head and neck, stomach, and breast carcinomas. Recently, 5-FU oral prodrugs, such as capecitabine, have been successfully introduced in cancer therapy, and their clinical use is rapidly and constantly growing. The approach to the prediction of severe toxicities due to 5-FU (and its oral prodrugs) has been matter of debate for many years and still remains a hot topic in oncology. The efforts in this field are almost entirely focused on the analysis of dihydropyrimidine dehydrogenase (DPD) gene mutations and of peripheral blood mononuclear cell (PBMC) DPD activity. For these reasons, in this letter we would like to suggest a novel, rational diagnostic algorithm that, integrating the analysis already available, is centred on the use of 5-FU and 5-fluoro-5,6-dihydrouracil (5-FDHU) pharmacokinetics as a tool to prevent severe and life-threatening 5-FU toxicities in patients with impaired 5-FU metabolism. DPD plays a pivotal role in the metabolism of 5-FU [1] and, as such, a deficiency of DPD has been recognized as an important risk factor, predisposing patients to the development of severe toxicity. Numerous genetic [2, 3] and phenotypic (i.e. DPD activity, breath test or plasma dihydrouracil/uracil ratio) [4–6] approaches have been proposed to prevent life-threatening toxicities, and, in our opinion, the time has come to develop an integrated approach to this clinically relevant issue. The screening of DPYD mutations [3] and of peripheral blood mononuclear cell DPD activity [7] in patient candidates for 5-FU treatment has been proposed as a routine approach to identify severely reduced DPD activity. However, both the genotype and phenotype options have some advantages but also limitations, as comprehensively pointed out by Ezzeldin and Diasio [8]. In order to identify all patients with impaired 5-FU clearance, no matter which type of DPYD mutations or DPD activity in PBMC compartment they have, in the last decade some authors have suggested a phenotypic approach of screening, looking at the systemic 5-FU catabolism and measuring the pharmacokinetic parameters of the parental drug and of its principal metabolite 5-FDHU [9–11]. As an example, our group has recently proposed the administration of a 5-FU test dose in patient candidates for 5-FU chemotherapy to calculate the pharmacokinetic parameters, such as 5-FU clearance and t1/2β or 5-FDHU Cmax, Tmax and t1/2β, that could be profoundly altered in the presence of an impaired systemic clearance [12]. Indeed, our study revealed markedly impaired 5-FU and 5-FDHU kinetics in some patients, as previously shown for patients with severe toxicities in other published studies [13], suggesting a possible profound alteration of 5-FU metabolism; owing to the detection of this abnormality, these subjects were not given a potentially life-threatening standard dose of 5-FU. Moreover, based on our experimental data, statistically significant relationships have been demonstrated between 5-FDHU pharmacokinetic parameters and moderate to severe degrees of three major dose-limiting toxicities related to 5-FU treatments (stomatitis, diarrhoea and neutropenia) after the first cycle of 5-FU standard therapy. In particular, a prolonged 5-FDHU t1/2β and a 5-FDHU Tmax higher than the median value of our population (30 min) could help identify patients at risk of developing moderate to severe neutropenia or diarrhoea [12]. The 5-FU test dose can be easily performed in a hospital setting with a clinical pharmacology unit such as those usually present in medium- or large-sized university hospitals of Western countries. In particular, an organized regional network among major clinical oncology units may allow screening patients within 2–3 days. The analysis can be available in a few days and the patients can be ready to start the 5-FU therapy at standard or reduced dose in the following week when 5-FU and 5-FDHU kinetic parameters are available. Based on this clinical experience, we detail the principles that should guide the decision-making process regarding the prevention of 5-FU severe toxicity and propose a diagnostic algorithm (Figure 1) in order to screen candidate patients to fluoropyrimidine therapy. In the suggested diagnostic algorithm (Figure 1), the predictive 5-FU test dose could be regarded as a triage test, allowing detection of the fraction of patients with normal, impaired or absent fluoropyrimidine metabolism. Other analyses, such as DPD genotyping or even DPD PBMC activity, could be used later as add-on tests and, limited to the still undiagnosed subgroup, to detect those degrees of enzyme activity impairment suitable for possible reduction of 5-FU dose or different treatments. Overall, the published data strongly suggest the use of a diagnostic algorithm based on the sequential application of a 5-FU pharmacokinetic test followed by DPD genotyping and activity in order to make a highly probable diagnosis of altered 5-FU metabolism. Moreover, the application of this model could result in a consistent reduction of costs and morbidity, by limiting genotyping and PBMC DPD activity analysis to only selected subgroups of patients. Figure 1 Suggested diagnostic flow chart for the detection of patients with impaired fluoropyrimidine metabolism. 5-FU, 5-fluorouracil; 5-FDHU, 5-fluoro-5,6-dihydrouracil; DPD, dihydropyrimidine dehydrogenase; PBMC, peripheral blood mononuclear cell; PK, pharmacokinetics; ... In conclusion, the published clinical experience suggests that an integrated approach based on pharmacokinetic analysis combined with DPD genotyping and/or phenotyping seems to be a safer strategy for optimizing the administration of 5-FU and its oral prodrugs, which remain major drugs used extensively in clinical oncology.

The wide distribution of ATP and adenosine receptors as well as enzymes for purine metabolism in different gut regions suggests a complex role for these mediators in the regulation of gastrointestinal functions. Studies in rodents have shown a significant involvement of adenosine in the control of intestinal secretion, motility and sensation, via activation of A1, A2A, A2B or A3 purinergic receptors, as well as the participation of ATP in the regulation of enteric functions, through the recruitment of P2X and P2Y receptors. Increasing interest is being focused on the involvement of ATP and adenosine in the pathophysiology of intestinal disorders, with particular regard for inflammatory bowel diseases (IBDs), intestinal ischemia, post-operative ileus and related dysfunctions, such as gut dysmotility, diarrhoea and abdominal discomfort/pain. Current knowledge suggests that adenosine contributes to the modulation of enteric immune and inflammatory responses, leading to anti-inflammatory actions. There is evidence supporting a role of adenosine in the alterations of enteric motor and secretory activity associated with bowel inflammation. In particular, several studies have highlighted the importance of adenosine in diarrhoea, since this nucleoside participates actively in the cross-talk between immune and epithelial cells in the presence of diarrhoeogenic stimuli. In addition, adenosine exerts complex regulatory actions on pain transmission at peripheral and spinal sites. The present review illustrates current information on the role played by adenosine in the regulation of enteric functions, under normal or pathological conditions, and discusses pharmacological interventions on adenosine pathways as novel therapeutic options for the management of gut disorders and related abdominal symptoms.

Irinotecan (CPT-11) significantly improves the efficacy of colorectal cancer treatment, demonstrating a superior efficacy with respect to leucovorin-modulated 5-fluorouracil (5-FU), also in fluoropyrimidine-resistant neoplasms. Preclinical studies demonstrated the inhibition of topoisomerase I by CPT-11 active metabolite 7-ethyl-10- hydroxycamptothecin (SN-38), and the possible synergistic interaction with other drugs effective against colorectal cancer, including 5-FU and oxaliplatin. Because of the occurrence of toxicities due to the large interpatient variability in drug metabolism, irinotecan is a candidate for therapeutic drug monitoring and pharmacokinetic optimisation. New schedules of drug administration (i.e. prolonged infusion) have led to improved cytotoxic effect of irinotecan, which resulted in improved overall survival and time to relapse together with reduced toxicity in comparison with 5-FU-based regimens. Furthermore, the analysis of the conversion of irinotecan into SN-38 by carboxylesterase, the detoxification of irinotecan and SN-38 by CYP3A4 and UDP-glucuronosyl transferases, and the activity of excretory systems (i.e., cMOAT, P-gp and MRP) seems able to predict the interindividual variability in pharmacokinetics and pharmacodynamics, being possible to predict untolerable toxicities. Finally, pharmacogenetics may elucidate drug interaction and gene expression modulation by irinotecan, while pharmacokinetic/pharmacodynamic models represent a valuable approach to further define the pharmacologic profile of irinotecan and improve its therapeutic index.

Nonsteroidal anti-inflammatory drugs delay gastric ulcer healing, and the ability of proton pump inhibitors to counteract this detrimental effect is debated. This study evaluates the effects of pantoprazole on experimental gastric ulcer healing in the presence of indomethacin. Rats with acetic-acid-induced gastric ulcers were orally treated for 3 or 7 days with pantoprazole (15 micromol/kg/day) or famotidine (20 micromol/kg/day), alone or in combination with indomethacin (3 micromol/kg/day). Ulcerated tissues were processed to assess ulcer area, malondialdehyde, proliferating cell nuclear antigen (PCNA) and cleaved caspase-3. Experiments on pylorus-ligated rats indicated that pantoprazole and famotidine were employed at equivalent inhibitory doses on gastric acid secretion (-67.9% and -64.5%, respectively). Indomethacin delayed ulcer healing both at days 3 and 7 (+22 and +35 mm(2) vs control ulcer, respectively). At day 3, pantoprazole was more effective than famotidine in promoting ulcer healing in indomethacin-treated animals (-53.6 and -31.6 mm(2) vs indomethacin, respectively). Malondialdehyde levels and caspase-3 activation in ulcers were increased by indomethacin (+79% and +3.7 folds vs control ulcer, respectively), and these effects were counteracted by pantoprazole (-77.9% and -3.5 folds vs indomethacin, respectively), but not famotidine. Increments of ulcer PCNA expression (+2.5 folds vs normal) were enhanced further by pantoprazole or famotidine, alone or in combination with indomethacin (+8.6 and +10.3 folds vs normal, respectively). Similar results were obtained after 7-day treatments of ulcerated animals with test drugs. It is concluded that, along with acid suppression, pantoprazole exerts acid-independent effects on ulcer healing, which can be ascribed to a decrease in tissue oxidation and apoptosis.

A key focus of research on pancreatic ductal adenocarcinoma (PDAC) is identifying new techniques to tailor gemcitabine and 5-fluorouracil treatments. Availability of tumor tissue is critical for the accurate assessment of gene expression, and laser microdissection (LMD) and primary cell cultures may be useful tools to separate tumor cells from the stromal reaction. The aim of this study was (1) to address the genetic profile relevant to drug activity and (2) to evaluate differences between microdissected and non-microdissected tumors, normal tissues, and primary cell cultures. Quantitative PCR of seven key genes was performed on mRNA from 113 microdissected and 28 non-microdissected tumors, a pool of normal tissues and four established primary cell lines. Protein expression was evaluated by western blot and immunocytochemistry and cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. LMD allowed the analysis of 110 samples and revealed significant differences in mRNA levels between microdissected tumors and normal tissues, as well as between non-microdissected and microdissected tumors from the same patients. In contrast, primary cell lines showed similar expression profiles with respect to their respective microdissected tumors. In particular, expression levels of human equilibrative nucleoside transporter-1 and thymydilate synthase were significantly related to gemcitabine and 5-fluorouracil cytotoxicity. We conclude that LMD is a reliable technique for mRNA extraction, and allows detection of significant differences in the expression of specific target genes when compared to non-microdissected specimens and normal tissues. Moreover, expression levels in microdissected tumors are similar to those observed in primary tumor cell cultures, both at mRNA and protein level, and are related to drug chemosensitivity. The use of these ex vivo techniques for molecular analysis of tumors therefore appears to be of some value in implementing the clinical management of PDAC.

NSAIDs are widely prescribed for the treatment of pain, inflammation and rheumatic disorders, but their use is associated with adverse gastrointestinal effects, ranging from dyspeptic symptoms and peptic ulcers to more serious complications. Elderly patients are at high risk of experiencing NSAID-induced gastrointestinal tract injury and should be considered candidates for prophylactic pharmacological therapy. In studies conducted in adult patients, proton pump inhibitors (PPIs) such as esomeprazole have been shown to prevent or reduce NSAID-induced gastrointestinal injury. The beneficial effects of esomeprazole can be ascribed largely to its ability to maintain sustained inhibition of gastric acid secretion, although there is evidence to suggest that pharmacodynamic properties unrelated to acid inhibition may also contribute to the gastroprotective effects of this agent. Although there are limited data on the use of esomeprazole specifically in elderly patient populations, studies of patients at high risk of NSAID-induced gastrointestinal toxicity because of advanced age indicate that this PPI is both effective and well tolerated when administered in conjunction with NSAIDs. Thus, esomeprazole can be regarded as a useful option for prophylactic therapy in elderly patients receiving long-term NSAID therapy.

Serotonin transporter (SERT) mediates the intracellular reuptake of released serotonin, thus regulating its biological functions. Abnormalities in serotonin reuptake can alter enteric serotonergic signalling, leading to sensory, motor and secretory gut dysfunctions, which contribute to the pathophysiology of irritable bowel syndrome (IBS). This relationship has fostered the use of selective serotonin reuptake inhibitors (SSRIs) in the treatment of IBS. Current data on the efficacy of SSRIs in IBS, association of the SERT gene promoter polymorphism 5-HTTLPR with IBS and the expression pattern of SERT in the intestinal mucosa of IBS patients are conflicting. Recent molecular studies have raised critical questions about multiple SERT mRNA transcripts in the human gut, the role of polymorphic SERT promoter in the regulation of enteric SERT expression and the ability of 5-HTTLPR to affect human SERT gene transcription. The present review highlights recent advances in SERT genetics, discusses their implications for potential therapeutic applications of SSRIs in IBS and presents original suggestions for future investigations.