Pharmacokinetics, efficacy and safety of daclatasvir plus asunaprevir in dialysis patients with chronic hepatitis C: pilot study

The aim of this study was to evaluate the pharmacokinetic profile of daclatasvir (DCV) and asunaprevir (ASV) dual therapy in haemodialysis patients infected with hepatitis C virus (HCV). Eighteen haemodialysis patients and 54 patients with normal renal function were treated with DCV and ASV dual therapy for 24 weeks. We evaluated the pharmacokinetic profiles of DCV and ASV and examined the rate of sustained virological response 12 weeks after the end of treatment (SVR₁₂ ) and incidence of adverse events during treatment of haemodialysis patients infected with chronic HCV genotype 1 infection. To adjust for potential differences in baseline characteristics between haemodialysis patients and patients with normal renal function, we used propensity scores case-control matching methods. Area under the plasma concentration time curve from 0 to 6 h (AUC_{0-6 h} ) of DCV was slightly lower in haemodialysis patients than in patients with normal renal function (P > 0.6). AUC_{0-6 h} of ASV was significantly lower in haemodialysis patients (P = 0.012). SVR₁₂ rates were 100% (18/18) for haemodialysis and 96.2% (52/54) for patients with normal renal function. Changes in mean log₁₀ HCV RNA levels and viral response were higher in haemodialysis patients compared to patients with normal renal function. No discontinuations due to adverse events occurred. In conclusion, DCV and ASV dual therapy for HCV infection is effective and safe with similar results in haemodialysis patients compared to patients with normal renal function.

[Changes in platelet adenylyl cyclase system in alcoholics]

Platelet GTP binding protein (G protein) in 25 alcoholics with a first-degree alcoholic relative (family history positive alcoholic; FHP), in 25 alcoholics without alcoholic relatives (family history negative alcoholic; FHN) and in 25 controls without alcoholic relatives was investigated to determine whether this protein is a trait marker for alcoholism. The alcoholic subjects met DSM III-R criteria for alcohol dependence and had been abstinent from alcohol for at least one year. Lowered platelet guanine nucleotide (GppNHp)-stimulated adenylyl cyclase (AC) activity and reduced sensitivity of AC to ethanol were recognized in FHP but not in FHN. Remarkable reduction in ethanol enhancement of functional photoaffinity GTP (azidoanilido GTP; AAGTP) binding to Gs alpha and Gi alpha in platelet membrane was observed in FHP but not in FHN. A quantitative reduction in Gs alpha and GsH alpha (high molecular weight Gs alpha) levels as assessed by immunoblotting was seen in platelet membrane from FHP but not from FHN. These results indicate that the characteristic of platelet G protein may be used as a trait marker for alcoholism.

Antidepressants directly influence in situ binding of guanine nucleotide in synaptic membrane

The present study examined the in vitro effects of antidepressants on functional photoaffinity labeling of GTP binding protein. Saturation binding studies were performed by incubating membranes with increasing concentrations of [32P]-AAGTP, followed by UV irradiation and SDS-PAGE. The specifically bound isotherms for each of the G proteins studied showed characteristics of a one site model. Scatchard analysis revealed increases in the Bmax and Kd of AAGTP binding for each of the G proteins (especially stimulatory G proteins) with the addition of antidepressants such as amitriptyline, clomipramine, desipramine and mianserin but not with monoamine oxidase inhibitor, antipsychotics and axiolytics. These results suggested that drugs having antidepressive properties may directly affect G protein, especially Gs protein.

Alterations of guanine nucleotide-binding proteins in post-mortem human brain in alcoholics

Qualitative and quantitative alterations of G proteins in membrane preparations from parietal and temporal cortex regions in post-mortem brains obtained from alcoholics and controls matched with respect to age and post-mortem delay were investigated by Western-blotting with polyclonal antibodies against specific G protein subunits and functional photoaffinity GTP binding. Quantitative immunoblotting showed that only Gs alpha (52 kDa species) in temporal cortex was significantly decreased (30%, P < 0.05) in alcoholics compared with controls. Moreover, ethanol-stimulated photoaffinity GTP labeling of Gs alpha and Gi/o alpha was decreased in alcoholics in both cortex regions. These results suggest that disturbances of G protein-mediated signal transduction may be involved in the pathophysiology of alcoholics.

[Effects of ethanol on GTP-binding protein function in human brain cortex]

The effect of ethanol "in vitro" on GTP-binding protein in postmortem human brain cortex membranes was analyzed using by photoaffinity hydrolysis resistant GTP analog (azidoanilido GTP, AAGTP). AAGTP identified stimulatory GTP binding protein [Gs alpha (42 KDa)] and inhibitory GTP binding protein [Gi alpha (40 KDa)] in human brain cortex membranes. Ethanol augmented the amount of AAGTP binding to both Gs alpha and Gi alpha in human temporal and parietal cortex membranes. These results show that ethanol "in vitro" elevates not only Gs functions but also Gi functions in postmortem human brain cortex.

[Platelet adenylate cyclase activity in alcoholics]

Platelet adenylate cyclase (AC) activity in the long-term abstinent alcoholics, who maintained abstinence from alcohol for at least one year was examined. Guanine nucleotide [Gpp(NH)p] stimulated AC activity was not changed in platelet membrane from long-term abstinent alcoholics. However, the extent of AC activity induced by 250 mM ethanol in vitro, in the presence of 1 microM Gpp(NH)p, was significantly reduced in platelet membrane from long-term abstinent alcoholics. These results suggest that platelet AC activity may be a biological marker for alcoholics.

[Lymphocyte adenylate cyclase activity in alcoholics]

Lymphocyte adenylate cyclase (AC) activity in alcoholics was examined. Gpp(NH)p-stimulated AC activity was not altered in lymphocyte membranes from alcoholics in acute withdrawal state. In the case of long-term abstinent alcoholics, who maintained abstinence from alcohol for at least one year, lymphocyte Gpp(NH)p-stimulated AC activity was slightly reduced but not significantly. However, the extent of AC activity induced by 250 mM ethanol in vitro, in the presence of Gpp(NH)p, was significantly reduced in lymphocyte membrane from long-term abstinent alcoholics. These results indicate that lymphocyte AC activity is a biological marker for alcoholics.