Toxin pharmacology of the large-conductance Ca2+-activated K+ channel in the apical membrane of rabbit proximal convoluted tubule in primary culture

The patch-clamp technique was used to study the toxin pharmacology of the large-conductance Ca²⁺-activated K⁺ channel (BKCa) present in the apical membrane of rabbit proximal convoluted tubules (PCT) in primary culture. Experiments were performed with the inside-out configuration. This channel was very selective for K⁺ against Na⁺ and had a conductance of 180 pS with 140 mmol/l in the pipette and the bath. The action of toxins was studied on the extracellular side of the channel by using the pipette perfusion technique. Experimental conditions were 140 mmol/l KCl in the pipette and 140 mmol/l Nad in the bath. Pipette potential was maintained at 0 mV. Perfusion of crude venom from Leiurus quinquestriatus hebraeus inhibited reversibly the open probability (P _o) in a concentration-dependent fashion (IC₅₀=0.8 mg/l; n=3). The following synthetic or purified toxins were tested: synthetic charybdotoxin (ChTX) IC₅₀=7.3×10^–9 M (n=5); iberiotoxin (IbTX) IC₅₀=5.5×10^–7 mol/l (n=3); and kaliotoxin (KTX) IC₅₀=4.8×10^–7 mol/l (n=3). The suppression of the six first N-terminal amino-acids slightly reduced the affinity of ChTX (IC₅₀=1.2×10^–8 mol/l, n=4). Neither Dendroaspis polylepis venom nor purified dendrotoxin modified P _o even at high concentrations (20 mg/l and 10^–6 mol/l respectively). Apamin, which blocked the small-conductance K⁺ channel in cultured PCT, did not act on BKCa. These results indicate that ChTX is the most efficient known toxin against the epithelial BKCa in primary cultures of PCT. In spite of there being considerable homology of sequence between ChTX, IbTX and KTX, ChTX was about 100 times more effective than the others. Truncated ChTX kept a high affinity for this channel and could be used to obtain a labelled probe.     

Influence of dietary soy isoflavones on the accessory sex organs of the Wistar rat.

We evaluated the effects of three rodent diets differing in soybean meal content on the response of the seminal vesicles, prostate and bulbocavernosus/levator ani (BC/LA) muscle to androgens and anti-androgenic compounds in the Hershberger assay. The diets tested were (1) L5, a semi-synthetic phytoestrogen-free diet, (2) DO4, 8.5% (w/w) vegetable protein and (3) DO3, 22.5% (w/w) vegetable protein. We determined the effects of dietary soy isoflavones after ten days of exposure and in animals fed L5 and DO3 diets throughout their lifetime (including the period of treatment with androgenic or anti-androgenic compounds). After ten days of exposure, we observed no effect of diet on the accessory sex organs of male Wistar rats. In contrast, diet affected the androgenic response to testosterone propionate in seminal vesicles and prostate. Seminal vesicles were the most sensitive organs. Vinclozolin caused a dose-dependent decrease in the relative weights of seminal vesicles, prostate and BC/LA regardless of diet. As vegetable proteins may contain high proportions of genistein and daidzein, two well-known oestrogenic endocrine disrupters that may alter the results of reproductive studies, we recommend the use of a standardised open-formula diet without soy isoflavones, such as L5, if the Hershberger assay is to be performed.     

Prevalence and burden of bipolar disorders in European countries.

A literature search, supplemented by an expert survey and selected reanalyses of existing data from epidemiological studies was performed to determine the prevalence and associated burden of bipolar I and II disorder in EU countries. Only studies using established diagnostic instruments based on DSM-III-R or DSM-IV, or ICD-10 criteria were considered. Fourteen studies from a total of 10 countries were identified. The majority of studies reported 12-month estimates of approximately 1% (range 0.5-1.1%), with little evidence of a gender difference. The cumulative lifetime incidence (two prospective-longitudinal studies) is slightly higher (1.5-2%); and when the wider range of bipolar spectrum disorders is considered estimates increased to approximately 6%. Few studies have reported separate estimates for bipolar I and II disorders. Age of first onset of bipolar disorder is most frequently reported in late adolescence and early adulthood. A high degree of concurrent and sequential comorbidity with other mental disorders and physical illnesses is common. Most studies suggest equally high or even higher levels of impairments and disabilities of bipolar disorders as compared to major depression and schizophrenia. Few data are available on treatment and health care utilization.     

Hepatic arterial oxaliplatin infusion plus intravenous chemotherapy in colorectal cancer with inoperable hepatic metastases: a trial of the gastrointestinal group of the Federation Nationale des Centres de Lutte Contre le Cancer.

PURPOSE: Isolated hepatic metastases of colorectal cancer constitute a frequent and serious therapeutic problem that has led to the evaluation of hepatic arterial infusion (HAI) of different drugs. Oxaliplatin combined with fluorouracil (FU) and leucovorin is effective in the treatment of colorectal cancer. In this context, a phase II study was conducted to evaluate concomitant administration of oxaliplatin by HAI and intravenous (IV) FU plus leucovorin according to the LV5FU2 protocol (leucovorin 200 mg/m(2), FU 400 mg/m(2) IV bolus, FU 600 mg/m(2) 22-hour continuous infusion on days 1 and 2 every 2 weeks). PATIENTS AND METHODS: Patients had metastatic colorectal cancer that was restricted to the liver and inoperable. The patients were not to have previously received oxaliplatin. After surgical insertion of a catheter in the hepatic artery, patients were treated with oxaliplatin 100 mg/m(2) HAI combined with FU + leucovorin IV according to the LV5FU2 protocol. Treatment was continued until disease progression or toxicity. Response was evaluated every 2 months. RESULTS: Twenty-eight patients were included, and 26 patients were treated. Two hundred courses of therapy were administered, and the median number of courses received was eight courses (range, zero to 20 courses). The most frequent toxicity consisted of neutropenia. The main toxicity related to HAI was pain. The intent-to-treat objective response rate was 64% (95% CI, 44% to 81%; 18 of 28 patients). With a median follow-up of 23 months, the median overall and disease-free survival times were 27 and 27 months, respectively. CONCLUSION: The combination of oxaliplatin HAI and FU + leucovorin according to the LV5FU2 protocol is feasible and effective in patients presenting with isolated hepatic metastases of colorectal cancer.     

Phase I combining a P-glycoprotein inhibitor, MS209, in combination with docetaxel in patients with advanced malignancies.

PURPOSE: The purpose of this study was to investigate the safety and tolerability of MS209, a potent inhibitor of P-glycoprotein, when given in combination with docetaxel and to determine whether MS209 affects docetaxel pharmacokinetics. EXPERIMENTAL DESIGN: Patients with advanced solid malignancies were eligible for this phase I trial. Docetaxel as 1-hour infusion was given alone during the first cycle. MS209 was introduced as of cycle 2 and given orally 30 minutes after docetaxel infusion. The dose escalation scheme followed a modified Fibonacci model with six steps (docetaxel, 60-100 mg/m2 and MS209, 300-1,200 mg per body). RESULTS: A total of 30 patients were treated at five dose levels. Dose-limiting toxicities were febrile neutropenia, infection, stomatitis, dysphagia, and fatigue. The maximum tolerated dose was reached at level 5 (docetaxel, 80-MS: 1,200). Pharmacokinetic analysis failed to show a strong pharmacokinetic interaction between the two compounds, but at the highest dose levels, there is a trend to an increase of docetaxel AUC when this agent is given in combination with MS209. CONCLUSION: MS209 can be given in combination with docetaxel, with limited effect on docetaxel toxicity or pharmacokinetics.     

Total soluble HLA class I and soluble HLA-G in multiple myeloma and monoclonal gammopathy of undetermined significance.

Serum beta2-microglobulin, the light chain of the HLA class I molecular complex, remains one of the best survival prognostic factors in multiple myeloma, but other HLA class I molecules might be of interest in monoclonal gammopathies. In this study, we evaluate total soluble HLA class I (HLA-Is) and soluble HLA-G (HLA-Gs) in 103 patients with newly diagnosed multiple myeloma, 30 patients with monoclonal gammopathy of undetermined significance (MGUS), and 30 healthy subjects, studying their prognostic value in multiple myeloma. In multiple myeloma patients, HLA-Is and HLA-Gs median values were 0.8 microg/mL and 28 ng/mL, respectively. Median HLA-Is concentration was higher in stage II and III multiple myeloma patients than in stage I multiple myeloma, MGUS, and control patients. Median HLA-Gs was significantly lower in healthy controls than in MGUS and multiple myeloma patients. A high level of HLA-Is (> or =2.1 microg/mL) was predictive of short survival (P = 0.017). For each given level of beta2-microglobulin, the relative risk of death was higher for patients with HLA-Is > or = 2.1 microg/mL than in patients with a lower level (P = 0.047). HLA-Gs, a marker of monoclonal gammopathy, was of no prognostic value, but the addition of HLA-Is to beta2-microglobulin produced an efficient prognostic score (P < 0.0001). HLA-Is is a new marker of multiple myeloma tumor load and provides additional survival prognostic information to beta2-microglobulin.     

Novel 2(3H)-Benzothiazolones as Highly Potent and Selective Sigma-1 Receptor Ligands

In an effort to produce a new pharmacological probe with high affinity and selectivity for the sigma-1 receptor, we have synthesized a series of original 2(3H)-benzothiazolones utilizing compound 4 [3-(1-piperidinoethyl)-6-propylbenzothiazolin-2-one] as a lead. Receptor binding affinities were determined at sigma-1 and sigma-2 receptors. The best ligand (9, sigma-1 K_i = 0.56 nM, selectivity ratio >1000) was obtained with an azepine side-chain. When tested on a wide battery of receptors, including 5HT_2A(h), 5HT₃(h), α₁, α ₂, β₁, β₂, H₁, H₂, opioids, D₁(h), D₂(h), 5HT uptake, and DOPA uptake, compound 9 showed submicromolar affinity only for α₂ (K_i = 205 nM) and H₁ (K_i = 311 nM).     

Consequences of xenoestrogen exposure on male reproductive function in spottail shiners (Notropis hudsonius).

There is limited information on the physiological consequences associated with exposure to xenoestrogens under field conditions. The objectives of this study were to determine the presence of estrogenic chemicals in the St. Lawrence River and their effects on male reproduction in the spottail shiner (Notropis hudsonius). Hepatic vitellogenin (VTG) mRNA levels in immature shiners indicate extensive estrogenic contamination spanning almost 50 km both upstream and downstream from the island of Montreal. Stages of spermatogenesis were assessed in fish captured at sites having varying levels of estrogenic contamination. In control fish, 95% had testis of either stage IV (50%) or stage V (45%) of spermatogenesis. At Ile Dorval, where VTG mRNA levels are moderate, fish had testes of stage III (38%) and IV (45%) and only 15% of fish were at spermatogenic stage V. In contrast, at Ilet Vert and Ile Beauregard, located in the sewage effluent plume from the City of Montreal and where hepatic VTG mRNA levels are high in fish, none of the fish were at stage V and 8% of fish at Ilet Vert were at stage II of development. Sperm concentration and various motility parameters were significantly lower in shiners from Ilet Vert as compared with those from Iles de la Paix (reference). Histological analyses of testes revealed that more than one-third of the fish captured at sites with the highest estrogenic contamination displayed intersex, a condition in which ovarian follicles were developing within the testis. These data indicate that there is significant estrogenic contamination in the St. Lawrence River that is associated with impaired reproductive function in male fish.