The bulky N6 substituent of cabergoline is responsible for agonism of this drug at 5-hydroxytryptamine 5-HT2A and 5-HT2B receptors and thus is a determinant of valvular heart disease

Fibrotic valvular heart disease (VHD) has been observed in patients with Parkinson's disease treated with dopamine receptor agonists such as pergolide and cabergoline. 5-Hydroxytryptamine(2B) receptor (5-HT(2B)R) agonism is the most likely cause, but other 5-HT receptors may also play a role in VHD. We aimed at characterizing the molecular fragment of cabergoline responsible for agonism at 5-HT(2B)R and 5-HT(2A)R. Cabergoline with an allyl substituent at N(6) behaved as a potent 5-HT(2B)R full agonist in relaxation of porcine pulmonary arteries and as a weaker 5-HT(2A)R partial agonist in contraction of coronary arteries. The same was true for cabergoline derivatives with cyclopropylmethyl, propyl, or ethyl at N(6). However, agonism was converted into antagonism, when the N(6) substituent was methyl. 6-Methylcabergoline retained agonism compared with cabergoline at human dopamine D(2LONG) and human dopamine D(2SHORT) receptors as determined by guanosine 5'-O-(3-[(35)S]thio)triphosphate binding. In porcine aortic valve cusps, 5-HT-induced contractions were inhibited by ketanserin (5-HT(2A/2C)R antagonist) but not by N-(1-methyl-1H-5-indolyl)-N'-(3-methyl-5-isothiazolyl)urea (SB204741) (5-HT(2B)R antagonist). In porcine valvular interstitial cells, cabergoline-induced activation of extracellular signal-regulated kinase (ERK) 1/2, an initiator of cellular proliferation and activity, was blocked by (R)-(+)-4-(1-hydroxy-1-(2,3-dimethoxyphenyl)methy1)-N-2-(4-fluorophenylethyl)piperidine (MDL100907) (5-HT(2A)R antagonist) and N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)-1,1'-biphenyl-4-carboxamide (GR127935) (5-HT(1B)R antagonist), whereas the stimulatory effect on [(3)H]proline and [(3)H]glucosamine incorporations (indices of extracellular matrix collagen and glycosaminoglycan) was blocked by MDL100907. We conclude that the bulky N(6) substituent of cabergoline is responsible for 5-HT(2A)R and 5-HT(2B)R agonism. The increased ERK1/2 phosphorylation and production of extracellular matrix by cabergoline are mediated by 5-HT(2A)Rs. However, the moderate potency of cabergoline at native 5-HT(2A)Rs suggests that these are not the preferential target in VHD in vivo.     

Possible role of MDR1 two-locus genotypes for young-age onset ulcerative colitis but not Crohn’s disease

Background The role of the single nucleotide polymorphisms (SNPs) on positions 2677G>T/A and 3435C>T of the multi-drug-resistance gene 1 (MDR1) in inflammatory bowel disease (IBD) remains unclear. Aims To further elucidate the potential impact of MDR1 two-locus genotypes on susceptibility to IBD and disease behaviour. Patients and methods Three hundred eighty-eight German IBD patients [244 with Crohn’s disease (CD), 144 with ulcerative colitis (UC)] and 1,005 German healthy controls were genotyped for the two MDR1 SNPs on positions 2677G>T/A and 3435C>T. Genotype–phenotype analysis was performed with respect to disease susceptibility stratified by age at diagnosis as well as disease localisation and behaviour. Results Genotype distribution did not differ between all UC or CD patients and controls. Between UC and CD patients, however, we observed a trend of different distribution of the combined genotypes derived from SNPs 2677 and 3435 (χ² = 15.997, df = 8, p = 0.054). In subgroup analysis, genotype frequencies between UC patients with early onset of disease and controls showed significant difference for combined positions 2677 and 3435 (χ² = 16.054, df = 8, p = 0.034 for age at diagnosis ≥25, lower quartile). Herein the rare genotype 2677GG/3435TT was more frequently observed (odds ratio = 7.0, 95% confidence interval 2.5 – 19.7). In this group severe course of disease behaviour depended on the combined MDR1 SNPs (χ² = 16.101, df = 6, p = 0.017 for age at diagnosis ≥25). No association of MDR1 genotypes with disease subgroups in CD was observed. Conclusions While overall genotype distribution did not differ, combined MDR1 genotypes derived from positions 2677 and 3435 are possibly associated with young age onset of UC and severe course of disease in this patient group.     

Effects of iodoproxyfan,a potent and selective histamine H3 receptor antagonist,onα 2 and 5-HT3 receptors

We determined the affinity and/or potency of the novel H₃ receptor antagonist iodoproxyfan at ₂ and 5-HT₃ receptors. Iodoproxyfan and rauwolscine (a reference ₂ ligand) (i) monophasically displaced³H-rauwolscine binding to rat brain cortex membranes (pK_i 6.79 and 8.59); (ii) facilitated the electrically evoked tritium overflow from superfused mouse brain cortex slices preincubated with³H-noradrenaline (pEC₅₀ 6.46 and 7.91) and (iii) produced rightward shifts of the concentration-response curve (CRC) of (unlabelled) noradrenaline for its inhibitory effect on the evoked overflow (pA₂ 6.65 and 7.88). In the guinea-pig ileum, iodoproxyfan 6.3µmol/l failed to evoke a contraction by itself but depressed the maximum of the CRC of 5-hydroxytryptamine (pD₂ 5.24). Tropisetron (a reference 5-HT₃ antagonist) produced rightward shifts of the CRC of 5-hydroxytryptamine (pA₂ 7.84). In conclusion, the affinity/potency of iodoproxyfan at H₃ receptors (range 8.3-9.7 [1]) exceeds that at ₂ receptors by at least 1.5 log units and that at 5-HT₃ receptors by at least 3 log units.     

雷公藤红素对IL-1和IL-2活性及PGE2释放的抑制作用

雷公藤红素0.1～1.0μg/ml在试管内能降低LPS诱导的小鼠腹腔巨噬细胞外和细胞内白细胞介素-1(IL-1)的活性,也能抑制ConA诱导的小鼠脾细胞产生白细胞介素-2(IL-2).动态观察表明,雷公藤红素经预处理8h和3h后已能分别抑制IL-1和IL-2的产生。此外,雷公藤红素能降低A23187刺激家兔滑膜细胞释放前列腺素E₂(PGE₂)。     

Lisuride, a dopamine receptor agonist with 5-HT2B receptor antagonist properties: absence of cardiac valvulopathy adverse drug reaction reports supports the concept of a crucial role for 5-HT2B receptor agonism in cardiac valvular fibrosis

OBJECTIVES: The high incidence of fibrotic cardiac valvulopathies reported in association with the 8beta-ergoline dopamine (DA) agonist, pergolide, and also case reports for cabergoline and bromocriptine have made it necessary to review the theoretical basis and actual findings in the case of another DA agonist, the 8alpha-ergoline lisuride (used since the 1970s for migraine prophylaxis as well as since the 1980s for its prolactin-lowering and anti-Parkinson activity). METHODS: We have reviewed the pharmacology of lisuride in relation to other DA agonists, and we have performed a throughout literature search as well as a search of our own and other adverse drug reaction databases for a possible relationship of lisuride with cardiac valvulopathy or for any reports of fibrosis in other locations. RESULTS: Our review of the pharmacology and the literature strongly suggests that drug-induced cardiac valvulopathies are always related to a stimulatory drug effect on trophic 5-HT(2B) receptors. As lisuride is devoid of such an effect, but on the contrary is an extremely potent 5-HT(2B) antagonist, an association of lisuride therapy with cardiac valvulopathies seems to be highly unlikely. In agreement with this hypothesis, not a single report of a cardiac valvulopathy associated with lisuride therapy has been identified in any database so far.Furthermore, against a background of an estimated 360,000 patient years, we have found only a very small number of cases of any other form of fibrosis (1x retroperitoneal, 2x pleural, 2x pulmonary, 1x interstitial pulmonary changes), in part combined with other risk factors and confounding variables. This closely matches 4 reports available from WHO (1x retroperitoneal, 3x pleural fibrosis). In addition, only 5 other possibly related conditions (3x pleural effusion, 1x pleuritis, 1x pericarditis) were identified in the lisuride adverse drug reaction database of Schering, Berlin. CONCLUSIONS: No link has been found between lisuride use and fibrotic cardiac valvulopathy, in agreement with the 5-HT(2B) receptor antagonist effect of this drug. The very low incidence of spontaneous reports of any other fibrosis could be even compatible with an association by chance in the population exposed to lisuride. Although close monitoring for this kind of side effects is still to be recommended in the therapy with lisuride, our data do not support the concept of a class effect suggesting that all ergot-derived drugs and especially DA receptor agonists with some chemical similarity to the ergot structure will cause or facilitate cardiac valvulopathies as observed with pergolide.     

Randomized phase II trial of gemcitabine and either day 1 or day 8 carboplatin for advanced non‐small‐cell lung cancer: Is thrombocytopenia predictable?

Aim:   Two 21-day gemcitabine–carboplatin schedules were evaluated in patients with advanced non-small cell lung cancer in order to assess the effect of timing of the carboplatin dose on toxicity and efficacy.
Methods:   Patients were randomized to gemcitabine (1000 mg/m² on days 1 and 8 of a 21-day cycle) and carboplatin (AUC 5, on day 1) (Carbo d1 arm) or the same gemcitabine schedule with carboplatin given on day 8 (Carbo d8 arm). Twenty patients with Stage IIIB or IV non-small-cell lung cancer were enrolled in each arm.
Results:   The achieved dose intensities of both gemcitabine and carboplatin were significantly higher in the Carbo d1 arm. The total rates of grade 3 or 4 hematological and non-hematological toxicities (any toxicity, any cycle) were 80% and 65%, respectively, with no significant differences between the two arms. Nine patients in the Carbo d1 arm, but only one patient in the Carbo d8 arm, required a platelet transfusion. There were 10 partial responses (four Carbo d1 arm, six Carbo d8 arm), giving an overall response rate of 25% (95% CI 13–41%).
Conclusion:   Administration of carboplatin on day 8 of this regimen confers no clear advantage compared with day 1 carboplatin, with similar toxicity but lower dose intensity. A formula for the prediction of thrombocytopenia is proposed.     

Increased frequency of congenital chromosomal aberrations in female partners of couples undergoing intracytoplasmic sperm injection

We evaluated the frequency of congenital chromosomal aberrations in a sample of 305 couples included in an intracytoplasmic sperm injection (ICSI) programme. Twenty individuals (3.3%) with congenital chromosomal abnormalities could be identified. The following types of abnormalities were observed: reciprocal translocations (n = 7), Robertsonian translocations (n = 3), inversions (n = 3), other structural aberrations (n = 4) and sex chromosome aberrations (n = 3). The rate of chromosomally abnormal males (10/305, 3.3%) lay within the expected range for patients with reduced semen quality. Surprisingly, 50% (10/20) of all abnormal karyotypes were contributed by the female partner of ICSI patients. These data confirm the higher incidence of chromosomal aberrations in infertile populations as compared with the baseline population risk. Additionally, the data imply that in some cases of male factor infertility a hidden female chromosomal factor may be present, which cannot be identified by standard clinical evaluation. In conclusion, we recommend chromosomal analysis in both partners of couples undergoing ICSI treatment.      

In vitro and in vivo antifungal activities of the eight steroid saponins from Tribulus terrestris L. with potent activity against fluconazole-resistant fungal pathogens

Antifungal activity of natural products is being studied widely. Saponins are known to be antifungal and antibacterial. We have isolated eight steroid saponins from Tribulus terrestris L. , namely TTS-8, TTS-9, TTS-10, TTS-11, TTS-12, TTS-13, TTS-14 and TTS-15. TTS-12 and TTS-15 were identified as tigogenin-3-O-β-D-xylopyranosyl（1→ 2）-[-β-D-xylopyranosyl（ 1 → 3 ） 3-β- D-glucopyranosyl （ 1 → 4 ）- 1- α-L-rhamnopyranosyl （ 1 → 2 ） 3-β-D-galactopyranoside and tigogenin-3-O-β-D-glucopyranpyranosyl（1→2）-[-β-D-xylopyranosyl（1→ 3）3-β-D-glucopyranosyl（1→4）-β-D-galactopyranoside, respectively. The in vitro antifungal activities of the eight saponins against six fluconazole-resistant yeasts, Candida albicans, Candida glabrata, Candida para psilosis , Candida tropicalis , Candida krusei , and Cryptococcus neo f ormans were studied using microbroth dilution assay. The results showed that TTS-12 and TTS-15 were very effective against several pathogenic candidal species and C. neoformans in vitro. It is noteworthy that TTS-12 and TTS-15 were very active against fluconazole-resistant C. albicans （MIC80 = 4.4, 9.4 mg/ml）, C. neoformans （MIC80 =10.7, 18.7 mg/ml） and inherently resistant C. krusei （MIC80 =8.8, 18.4 mg/ml）. So in vivo activity of TTS-12 in a vaginal infection model with fluconazole-resistant C. albicans was studied in particular. Our studies revealed TTS-12 also showed in vivo activities against fluconazole-resistant yeasts. In conclusion, steroid saponins TTS-12 and TTS-15 from Tribulus terrestris L. have significant in vitro antifungal activity against fluconazole-resistant fungi, especially TTS-12 also showed in vivo activity against fluconazole-resistant C. albicans.