Phase 3 trial of three thalidomide-containing regimens in patients with newly diagnosed multiple myeloma not transplant-eligible.

The introduction of agents such as thalidomide, lenalidomide, and bortezomib has changed the management of patients with multiple myeloma who are not eligible for autologous transplantation, many of whom are elderly. We sought to compare three thalidomide-based oral regimens among such patients in Latin America. We randomized patients with newly diagnosed multiple myeloma with measurable disease to one of the following regimens: melphalan, prednisone, and thalidomide (MPT); cyclophosphamide, thalidomide, and dexamethasone (CTD); and thalidomide and dexamethasone (TD). The TD arm was closed prematurely and was analyzed only descriptively. The primary endpoint was the overall response rate (ORR), whereas progression-free survival (PFS) and overall survival (OS) were secondary endpoints. The accrual rate was slower than expected, and the study was terminated after 82 patients had been randomized. The ORRs were 67.9 % with MPT, 89.7 % with CTD, and 68.7 % with TD (p = 0.056 for the comparison between MPT and CTD). The median PFS was 24.1 months for MPT, 25.9 months for CTD, and 21.5 months for TD. There were no statistically significant differences in PFS or OS between MPT and CTD. In an unplanned logistic regression analysis, ORR was significantly associated with treatment with CTD (p = 0.046) and with performance status of 0 or 1 (p = 0.035). Based on the current results, no definitive recommendations can be made regarding the comparative merit of the regimens tested. Nevertheless and until the results of further studies become available, we recommend either CTD or MPT as suitable frontline regimens for patients with multiple myeloma who are not candidates to transplantation in settings where lenalidomide and bortezomib are not available.

Molecular analysis and conventional cytology: association between HPV and bacterial vaginosis in the cervical abnormalities of a Brazilian population.

We investigated the association between bacterial vaginosis (BV) and human papillomavirus (HPV) infection in Papanicolaou smears in a Brazilian population. Cross-sectional analysis was performed on 673 samples collected from women attending public health centers in Olinda (PE, Brazil) by conventional cytology methodology and molecular analysis, PCR tests (GP5+/6+ and MY09/11). Cytological abnormalities, BV, and HPV-DNA were detected in 23 (3.4%) samples, 189 samples (28.1%), and 210 samples (31.2%), respectively. GP5+/6+ primers resulted in higher detection performance than MY09/11 primers, with 81% concordance between both primers (P < 0.0001). The occurrence of HPV-DNA and BV had ORs of 8.59 (P < 0.0001) and 2.91 (P = 0.0089) for abnormal cytology, respectively, whereas the concomitant presence of both infections showed an OR equal to 3.82 (P = 0.0054). Therefore, we observed an association between abnormal cervical cytology and HPV infection, BV, or both HPV infection and BV. These results highlight the necessity of monitoring patients presenting not only HPV, but also BV, as risk factors for cervical lesion development.

P2x-purinoceptors of myenteric neurones from the guinea-pig ileum and their unusual pharmacological properties.

1. Whole-cell and outside-out patch clamp recordings were used to characterize the physiological and pharmacological properties of the P2x-purinoceptors of myenteric neurones from the guinea-pig ileum. 2. Adenosine 5'-triphosphate (ATP) and analogues (1-3000 microM) evoked a rapid inward current in > 90% of all recorded neurones. The reversal potential of this current was dependent on the extracellular sodium concentration, at +14 +/- 1.9, 0 +/- 1.6 and -12 +/- 1 mV for 166, 83 and 42 mM of sodium, respectively. The fast activation and inactivation of this current occurred even when guanosine 5'-triphosphate (GTP) was omitted from the pipette solution or substituted with an equimolar concentration of guanosine 5'-o-[2-thiotriphosphate] (GTP-gamma-S). Single channel currents were observed when these outside-out membrane patches were exposed to ATP (10-30 microM). These channels have a unitary conductance of about 17 picosiemens. 3. The rank-order of potency of the agonists used to induce the whole-cell currents was: ATP-gamma-S = ATP = 2-methylthio-ATP (2-Me-S-ATP) > > alpha, beta-methylene ATP = beta, gamma-methylene ATP; adenosine and uridine 5'-triphosphate (UTP) (up to 1 mM) were inactive. 4. Pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) (1-30 microM) antagonized the effects of ATP (1 mM) with an IC50 of 4 microM. alpha, beta-Methylene ATP (100 microM) did not affect the ATP (30 microM)-induced current. Cibacron Blue 3GA increased the ATP activated cationic current whereas Basilen Blue E-3G had a very weak antagonistic effect (IC50 > or = 3 mM). Suramin potentiated the currents induced by ATP through a mechanism that was independent of its inhibitory effect on ectonucleotidase activity, as suramin also potentiated the effect of alpha, beta-methylene ATP (an ATP analogue that is resistant to nucleotidases). 5. In conclusion, the myenteric P2x-purinoceptor shares some properties with other purinoceptors in particular with the P2x4- and P2x6-purinoceptors. This receptor has also some unusual pharmacological properties suggesting that myenteric neurones express a novel subtype of P2x-purinoceptors. The properties of this receptor, however, might be a result of the combination of two or more of the homomeric purinoceptors so far characterized.

Melatonin modulates cholinergic transmission by blocking nicotinic channels in the guinea-pig submucous plexus.

Melatonin, a hormone produced and released by the pineal gland is also synthesized by cells of the gastrointestinal wall, where it might be a local regulator of gut functions. In this study, we investigated the possible role of melatonin as a modulator of the enteric nervous system. Intracellular recordings were made in neurons of the submucosal plexus from the guinea-pig ileum to measure the melatonin effects on their electrophysiological properties. Melatonin did not alter the membrane potential, the membrane resistance and the noradrenergic inhibitory postsynaptic potentials. However, melatonin (30-3000 microM) reversibly decreased the amplitude of nicotinic excitatory postynaptic potentials (EPSPs) in a concentration-dependent manner (IC50 = 247 microM). These actions of melatonin were not modified by the presence of idazoxan and atropine indicating that they are not mediated by endogenous release of acetylcholine, noradrenaline, or by direct activation of alpha 2-adrenoceptors or muscarinic receptors. The superfusion of melatonin also blocked the nicotinic depolarizations induced by locally applied acetylcholine, indicating that at least part of its effects are postsynaptic. In voltage-clamp experiments, using the whole-cell configuration, melatonin also inhibited the nicotinic inward currents induced by acetylcholine (IACh) in a concentration-dependent manner (IC50 = 257 microM). Melatonin decreased the maximal IACh but did not affect the potency of acetylcholine to induce this current, indicating a noncompetitive antagonism. This effect was voltage-dependent. Our observations indicate that melatonin inhibits the fast EPSPs by directly and specifically blocking the nicotinic channels. The relative high concentrations of melatonin required to produce such an effect rules this out as one of its humoral actions. Such an effect, however, might be of physiological significance close to the cells that release melatonin in the gastrointestinal wall or in other organs.

Cellular mechanisms underlying adenosine actions on cholinergic transmission in enteric neurons.

Whole cell recordings were used to investigate the effects of adenosine and several of its analogues on voltage-activated calcium currents (VACC) of myenteric and submucosal neurons. Electrophysiological and pharmacological properties of the soma VACC recorded in myenteric neurons indicate that they are carried through N-type calcium channels, similar to those of the submucosal neurons and to those of the calcium conductance that mediates acetylcholine release at the submucosal ganglia. Adenosinergic compounds inhibited, in a concentration-response and in a voltage-dependent manner, VACC in neurons from both enteric plexuses. The pharmacological profile of the receptors that mediate this effect was similar to that of the receptors involved in presynaptic inhibition in enteric neurons and likely of the A1 subtype. The effects of 2-chloroadenosine (CADO) on VACC were prevented by pretreatment with pertussis toxin (PTX), became irreversible with guanosine 5'-O-(3-thiotriphosphate) (inside the pipette), and were abolished with N-ethylmaleimide (NEM; known to uncouple receptors from G protein complexes). Intracellular recordings were used to further evaluate presynaptic effects of adenosine at the submucosal plexus. Adenosinergic compounds reduced the amplitude of fast excitatory postsynaptic potentials (EPSPs) by acting at nerve terminals. This effect was insensitive to PTX and staurosporine (a protein kinase inhibitor) but was abolished by NEM. CADO effects on EPSPs were not reversed by increasing the extracellular calcium concentration. In conclusion, activation of A1 adenosine receptors inhibits VACC via PTX-sensitive G proteins in myenteric and submucosal neurons. Reduction of cholinergic transmission also involves A1 adenosine receptors and appears to involve the activation of PTX-insensitive G proteins.