Synthesis and in vitro pharmacological evaluation of a new series of 5-HT1A 5-HT2A and 5-HT2C receptor ligands containing a norbornene nucleus.

A series of 4-substituted piperazine derivatives bearing a norbornene nucleus have been prepared and their affinity for serotonin 5-HT1A, 5-HT2A and 5-HT2C receptors has been evaluated. Compounds showing the highest affinity have been selected and evaluated on dopaminergic (D1 and D2) and adrenergic (alpha1 and alpha2) receptors. The combination of structural elements (heterocyclic nucleus, oxyalkyl chain and 4-substituted piperazine) known to be critical in order to have affinity on serotonin receptors and the proper selection of substituents led to compounds with higher receptor specificity and affinity. In binding studies, several molecules showed affinity in nanomolar range towards 5-HT1A, 5-HT2A and 5-HT2C receptors and moderate to no affinity for other relevant receptors (D1, D2, alpha1 and alpha2). Compound 2q 4-[2-[4-(3,4-dichlorophenyl)piperazin-1-yl]ethoxy]-4-aza-tricyclo[5.2.1.02,6]dec-8-ene-3,5-dione (Ki = 1.13 nM), was the most active and selective derivative for the 5-HT2C receptor with respect to other serotonin, dopaminergic and adrenergic receptors. Moreover, compound 3p showed mixed 5-HT2A/5-HT2C activity with affinity values in nanomolar range.

Retinopathy induced by drugs and herbal medicines.

Retina is the part of the eye suffering most damage from drugs. It is made up of a thin nervous membrane that covers the eye-ball internally, within the thickness of which three types of cells are ordered. In this paper we describe the drugs that are responsible for retinal side effects. Most commonly recognized drugs-induced retinopathy have a particular affinity for the retinal pigmented epithelium: antimalarials (quinine, hydroxychloroquine, mefloquine), phenothiazines, indomethacin, ethambutol, and desferrioxamine. Attention is especially focused on drugs more recently suspected of adverse reactions in the retina: vigabatrin, gabapentin, sildenafil, tamoxifen, isotretinoin, interferon, and omeprazole. Moreover, we referred some reports of retinopathy by herbal medicines and nutritional supplements (canthaxanthine, Gingko biloba L. and Glycyrrhiza glabra L.) This review is based on data published in scientific journals indexed by the PubMed and Medline databases. The last search of the literature was conducted in April 2008.

Synthesis of 6beta-D-glucosyl and 6-nitroxy (-)-galanthamine derivatives as acetylcholinesterase inhibitors.

Galanthamine is an alkaloid approved for the treatment of Alzheimer's disease. In this paper the syntheses and the anticholinesterase activities of new glucosyl and nitroxy derivatives substituted on position 6 are reported. Compounds 2, 3 and 5 presented a percentage of inhibition of 35.22%, 47.48% and 67.89% respectively.

Protective effect of silymarin on oxidative stress in rat brain.

Brain is susceptible to oxidative stress and it is associated with age-related brain dysfunction. Previously, we have pointed out a dramatic decrease of glutathione levels in the rat brain after acetaminophen (APAP) oral administration overdose. Silymarin (SM) is a mixture of bioactive flavonolignans isolated from Silybum marianum (L.) Gaertn., employed usually in the treatment of alcoholic liver disease and as anti-hepatotoxic agent in humans. In this study, we have evaluated the effect of SM on enzymatic and non enzymatic antioxidant defensive systems in rat brain after APAP-induced damage. Male albino Wistar rats were treated with SM (200 mg/kg/die orally) for three days, or with APAP single oral administration (3 g/kg) or with SM (200 mg/kg/die orally) for 3 days and APAP single oral administration (3 g/kg) at third day. Successively the following parameters were measured: reduced and oxidized glutathione (GSH and GSSG), ascorbic acid (AA), enzymatic activity variations of superoxide dismutase (SOD) and malondialdehyde levels (MDA). Our results showed a significant decrease of GSH levels, AA levels and SOD activity and an increase of MDA and GSSG levels after APAP administration. After SM administration GSH and AA significantly increase and SOD activity was significantly enhanced. In the SM+APAP group, GSH values significantly increase and the others parameters remained unchanged respect to control values. These results suggest that SM may to protect the SNC by oxidative damage for its ability to prevent lipid peroxidation and replenishing the GSH levels.

Chemotherapy-induced myelosuppression by vinorelbine: a comparison between different dose schedules by simulation.

A pharmacokinetic-pharmacodynamic (PK-PD) model was developed to simulate the plasma profile and the toxicity of vinorelbine after multiple oral dose treatment to humans. The PK drug profile was described by a three-compartment open model linked to a PD model aimed to describe the drug toxicity on the circulating neutrophils. Different dose schedules were simulated holding the total administered dose constant (100 mg p.o. during two weeks): 7.7 mg daily (13 doses), 20 mg every 3 days (5 doses) and 33.3 mg every 6 days (3 doses). The lowest values of the circulating neutrophils were observed after 18 days from the start of the treatment and at nadir the fraction of the circulating neutrophils were 0.733, 0.703 and 0.681 after the three doses in decreasing order. These differences were not clinically significant, however the drug bioavailability, which was fixed to 0.35 in the simulation, might be highly variable among subjects contributing to a large extent to the observed variability in drug toxicity.

Toxicological aspects of perinatal analgesia.

Perinatal exposure to analgesics and anesthetics is responsible of acute effects which are relatively easy to detect and, accordingly, a large number of clinical and experimental observations has been gathered. On the contrary, the possible long term consequences of perinatal administration of these drugs have recently become the object of great interest. It is possible, infact, that perinatal exposure to neurotropic agents may lead to long term neuropsychopharmacological effects that outlast the effective presence of the drug in the newborn. The conceptual framework of this hypothesis is provided by the modern concept of neuroplasticity, according to which early life experiences that serve to set the operating characteristics of the brain may represent the target of pharmacologically-induced chan-ges. Clinical studies have already provided evidence of the association between labour analgesia and the development of maladaptive behaviour in adult life, while experimental studies suggest that maternal care can actively program differences in gene expression through stable effects on the epigenome. Although they require to be confirmed by further studies possibly performed on wider cohorts, these results suggest caution in the use of obstetric pain relief methods that permit substantial passage of drugs through the placenta.

Pharmacokinetics of mitomycin C after resection of peritoneal carcinomatosis and intraperitoneal chemohyperthermic perfusion.

Over the last few years surgery on patients with abdominal malignancies has become more aggressive but the majority of patients present locoregional recurrence as peritoneal dissemination. Cytoreductive surgery followed by intraperitoneal chemohyperthermic perfusion (ICHP) has been described for treatment and prevention of locoregional cancer spread from various origins. This paper reports our study of the pharmacokinetics of mitomycin C (MMC) administered by intraperitoneal chemohyperthermic perfusion (ICHP) in patients with peritoneal carcinomatosis. 28 patients received MMC 20 mg/m2 intraperitoneally as a perfusion over 60 min. MMC was determined in perfusate, plasma and urine samples with a UV-HPLC method. A compartmental model was used to fit the drug concentrations in plasma and perfusate. Our results showed a mean maximum plasma concentration (Cmax) of 0.14 +/- 0.086 microg/ml with a peak time (Tmax) of 48..7 +/- 5.61 min. The mean area under the curve (AUC) and terminal half-life (t1/2) were 15.8 +/- 9.8 mg x min/L and 83.7 +/- 31.74 min respectively. Clearance (CL) was estimated by fitting the data by a compartmental model and the mean value was 72 +/- 66 L/h. The percent of the dose absorbed was very variable and ranged between 14 and 57% (mean 37 +/- 14%). The mean percentage of dose recovered unchanged in the urine during 24 hours was 7.21 +/- 3.73%. We conclude that ICHP in patients with peritoneal surface malignancies seems to have clinical value since it gives high peritoneal and tumor MMC concentrations with limited systemic exposure and toxicity.

A novel biweekly multidrug regimen of gemcitabine, oxaliplatin, 5-fluorouracil (5-FU), and folinic acid (FA) in pretreated patients with advanced colorectal carcinoma.

Previous results suggest that GEM affects 5-fluorouracil (5-FU) metabolism and pharmacokinetics in cancer patients, while combined with oxaliplatin, levo-folinic acid, and 5-FU (GOLF regimen), at doses achievable in cancer patients, determines high cytotoxic and proapoptotic antitumour activity in colon cancer cells in vitro. On these bases we designed a phase I-II clinical trial testing the GOLF regimen in patients with metastatic colorectal carcinoma, who had received at least a prior line of chemotherapy. In total, 29 patients (20 males and nine females) enrolled in the study received every 2 weeks, gemcitabine (patients #1-3 received 600 mg m(-2); patients # 4-6 received 850 mg m(-2); while patients # 7-29 received 1000 mg m(-2)) on the day 1, levo-folinic acid (100 mg m(-2)) on the days 1 and 2; 5-fluorouracil (400 mg m(-2)) in bolus injection, followed by a 22-h continuous infusion (800 mg m(-2)) on the days 1 and 2, and oxaliplatin (85 mg m(-2)), 6 h after the 5-FU bolus on day 2. The most frequent side effect was grade I-II haematological toxicity. In total, 28 patients were evaluable for response: three achieved a complete response, nine a partial response, 10 had a stable disease, and six progressed. The average time to progression and overall survival of the patients was, respectively, 7.26 and 22 months. Our GOLF combination is well tolerated and seems promising for the treatment of advanced colorectal cancer.

Tumour-associated antigen (TAA)-specific cytotoxic T cell (CTL) response in vitro and in a mouse model, induced by TAA-plasmids delivered by influenza virosomes.

We investigated influenza virosomes as a TAA-gene delivery system for use in TAA-directed anti-cancer vaccine therapy. An engineered plasmid (GC90) expressing the parathyroid hormone-related peptide (PTH-rP), a protein secreted by prostate and lung carcinoma cells, was included in influenza virosomes (GC90V). The ability of GC90V to elicit a PTH-rP-specific cytotoxic T cell (CTL) response was demonstrated in BALB/c mice immunised with intranasal (i.n.) GC90V+/-adjuvant subcutaneous (s.c.) interleukin-2 (IL-2). A PTH-rP-specific CTL response with antitumour activity was also demonstrated in human peripheral blood mononuclear cells (PBMC) stimulated in vitro with GC90V infected autologous dendritic cells (DC). These results provide a rationale for investigating GC90V in clinical trials of anticancer vaccine therapy.

In vitro generation of cytotoxic T lymphocytes against HLA-A2.1-restricted peptides derived from human thymidylate synthase.

5-Fluorouracil (5-FU) is a pyrimidine antimetabolite active against colorectal carcinoma and other malignancies of the digestive tract. Over-expression or mutation of thymidylate synthase (TS), the target enzyme of the 5-FU metabolite, 5-fluorodeoxyuridine monophosphate, is strictly correlated with cancer cell resistance to 5-FU. On this basis we investigated whether TS is a potential target for active specific immunotherapy of human colon carcinoma, which acquires resistance to 5-FU. Three TS-derived epitope peptides which fit defined amino acid consensus motifs for HLA-A2.1 binding were synthesized and investigated for their ability to induce human TS-specific cytotoxic T cell (CTL) responses in vitro. CTL lines specific for each peptide were established by stimulating peripheral blood mononuclear cells (PBMC) from an HLA-A2.1+ healthy donor with autologous dendritic cells loaded with TS peptide. Specific CTL lines showed HLA-A2.1-restricted cytotoxicity in vitro to HLA-A2.1+ target cells pulsed with the specific TS peptide and to HLA-class I matching colon carcinoma target cells over-expressing TS enzyme after exposure to 5-FU. Recognition by CTL lines suggests that these TS peptides may be potential candidates for use in a peptide-based vaccine against 5-FU resistant colon carcinoma.

High affinity central benzodiazepine receptor ligands: synthesis and structure-activity relationship studies of a new series of pyrazolo[4,3-c]quinolin-3-ones.

A large series of 2-aryl(heteroaryl)-2,5-dihydropyrazolo[4,3-c]quinolin- 3-(3H)-ones, carrying appropriate substituents at the quinoline and N2-phenyl rings, were prepared and tested as central benzodiazepine receptor ligands. Results from structure-affinity relationship studies were in full agreement with previously proposed pharmacophore models and, in addition, quantitative structure-activity analysis gave further significant insight into the main molecular determinants of high benzodiazepine receptor affinity. The intrinsic activity of some active ligands was also determined and preliminary discussed.

Chelating agents as potential antitumorals: alpha-(N)-heterocyclic hydrazones and bis-alpha-(N)-heterocyclic hydrazones.

A number of pyruvic acid and methylpyruvate alpha-(N)-heterocyclic hydrazones has been synthesized. Bis-heterocyclic hydrazones were obtained from reaction with pyruvic carboxaldehyde. Some complexes of Ni(II) were prepared and characterized as neutral complexes. All these compounds have been evaluated for cytotoxicity against P388 and HL-60 leukemia.