P-Glycoprotein-Mediated Transport of Itraconazole across the Blood-Brain Barrier

The mechanism for the accumulation of itraconazole (ITZ) in its elimination from the brain was studied in rats and mice. The concentration of ITZ in liver tissue declined in parallel with the plasma ITZ concentration until 24 h after intravenous injection of the drug (half-life, 5 h); however, the ITZ in brain tissue rapidly disappeared (half-life, 0.4 h). The time profiles of the brain/plasma ITZ concentration ratio (K_p value) showed a marked overshooting, and the K_p value increased with increasing dose; these phenomena were not observed in the liver tissue. This finding indicates the occurrence of a nonlinear efflux of ITZ from the brain to the blood. Moreover, based on a pharmacokinetic model which hypothesized processes for both nonlinear and linear effluxes of ITZ from the brain to the blood, we found that the efflux rate constant in the saturable process was approximately sevenfold larger than that in the nonsaturable process. The K_p value for the brain tissue was significantly increased in the presence of ketoconazole or verapamil. The brain K_p value for mdr1a knockout mice was also significantly increased compared with that of control mice. Moreover, the uptake of vincristine or vinblastine, both of which are substrates of the P glycoprotein (P-gp), into mouse brain capillary endothelial cells was also significantly increased by ITZ or verapamil. In conclusion, P-gp in the brain capillary endothelial cells participates in a process of active efflux of ITZ from the brain to the blood at the blood-brain barrier, and ITZ can be an inhibitor of various substrates of P-gp.     

Preponderance of hepatitis B virus genotype B contributes to a better prognosis of chronic HBV infection in Okinawa,Japan

The present study was designed to examine the distribution of hepatitis B virus (HBV) genotypes among patients at various stages of chronic liver disease type B in Okinawa Prefecture, Japan, where the prevalence of hepatitis B surface antigen is the highest in Japan despite the lowest mortality rate from primary liver cancer. Serum samples from 227 HBV carriers were determined for HBV genotype by polymerase chain reaction (PCR)-restriction fragment length polymorphism. Five of 227 sera were negative for HBV DNA by nested PCR and were excluded from the genotype analysis. Genotype B was predominant in asymptomatic carriers (45/67, 67%), whereas genotype C was predominant in chronic liver disease: 49% (50/103) in patients with chronic hepatitis, 63% (20/32) in patients with cirrhosis, and 60% (12/20) in patients with hepatocellular carcinoma. The distribution of genotype B decreased with increasing liver disease severity. However, this tendency was seen among patients aged less than 50 years old, whereas the prevalence of genotype B was similar among carriers with various liver diseases who were older than age 50. In conclusion, HBV genotype B was prevalent and less frequent among patients with advanced liver disease, particularly in patients aged less than 50 years. These findings suggest that the preponderance of genotype B is responsible for the low mortality rate of primary liver cancer associated with HBV seen in Okinawa Prefecture, despite having the highest HBV carrier rate in Japanese.     

Potential role of high molecular weight hyaluronan in the anti-Candida activity of human oral epithelial cells.

Candida albicans is both a commensal and a pathogen in the oral mucosa. Previous studies have indicated that epithelial cell-associated carbohydrate moiety can inhibit C. albicans growth. In the present study, the mechanisms by which epithelial cells inhibit Candida growth were studied by examining the effect of hyaluronan (HA). A coculture of C. albicans and KB cells or COS-7 cells inhibited in vitro growth of the fungus by 50-87% at an effector-to-target (E:T) ratio of 80:1. Removing extracellular HA by hyaluronidase caused a significant decrease in the anti-Candida activity of the cells. In addition anti-Candida activity was observed at 1 micro g/ml HA (2000 kDa). The antifungal activity of extracellular HA was further studied by transiently transfecting COS-7 cells with human HSA1, HSA2, or HSA3 in order to produce high levels of extracellular HA. All of the transfectants inhibited C. albicans growth in vitro by 51-65% compared to 38% inhibition by the vector control (P<0.05). These results suggest that the anti-Candida activity of epithelial-cells is mediated by extracellular HA.     

Production of dengue 2 envelope domain III in plant using TMV-based vector system

The envelope protein of dengue virus is the major protein involved in host cell receptor binding for viral entry and induction of immunity. A gene fragment encoding domain III of the dengue 2 envelope protein (D2EIII, amino acids 298-400) was successfully expressed in Nicotinana benthamiana plant using a tobacco mosaic virus (TMV)-based transient expression system. The N-terminal 5' untranslated region-omega sequence located upstream of D2EIII increased protein production in infected plant tissues. The recombinant protein was reactive with anti-D2EIII polyclonal and anti-His tag antibodies. The intramuscular immunization of mice with D2EIII induced the production of the anti-dengue virus antibody. The induced antibody demonstrated neutralizing activity against dengue type 2 virus. The result indicates that the TMV expression system produces the dengue virus antigen in plant, which possesses appropriate antigenicity and immunogenicity.     

Alanine aminotransferase (ALT) levels in a normal population and interferon therapy in chronic hepatitis C patients with normal ALT

BACKGROUND/AIMS: The aims of this study were to determine the distribution of serum alanine aminotransferase levels in a normal population and to clarify whether interferon treatment is justified in HCV-infected patients with persistently normal alanine aminotransferase levels. METHODOLOGY: The distribution of alanine aminotransferase levels was examined among 949 normal subjects who were negative for hepatitis viruses, denied regular alcohol use. Nineteen patients with chronic hepatitis C and persistently normal alanine aminotransferase levels were treated with alpha interferon (six or ten million units thrice weekly for six months). RESULTS: Peaks of alanine aminotransferase distribution among the normal subjects were seen at 16-20 IU/L and 11-15 IU/L in males and females, respectively. Fourteen of the 19 patients who received interferon treatment had favorable factors of response to interferon (eight with low pretreatment virus load, four with HCV genotype 2 and two with both). A sustained virological response was achieved in eight (57%) of 14, and alanine aminotransferase levels decreased significantly to within the normal range after interferon treatment in six of eight. CONCLUSIONS: Patients with chronic hepatitis C and persistently normal alanine aminotransferase levels should be treated with high doses of interferon if they have favorable factors of response to interferon treatment.     

Liver disease in hepatitis C virus carriers identified at blood donation and their outcomes with or without interferon treatment: Study on 1019 carriers followed for 5–10 years

Aim: To portray liver disease and project outcomes in carriers of hepatitis C virus (HCV) in the general population. Methods: Liver disease was evaluated in 1019 individuals who were found with HCV infection at blood donation, and they were followed for 5-10 years with or without receiving interferon (IFN). Results: At baseline, chronic hepatitis was detected in 529 (51.9%) HCV carriers and more frequently in men than in women (62.6% [299/478]vs 42.5% [230/541], P < 0.01); cirrhosis was diagnosed in five (0.5% [three men included]) and hepatocellular carcinoma (HCC) in one (0.1% [man]). Of the carriers who were followed for 5 years or longer, loss of HCV-RNA from serum was achieved in 61 (31.0%) of the 197 treated with interferon (IFN) and only one of the 211 (0.5%) without IFN (P < 0.0001). HCC developed in 14 carriers including six ofthe 211 (2.8%) without IFN and eight of the 197 (4.1%) with IFN (six non-responders included). Follow ups of the 949 carriers identified age (P < 0.002), male gender (P < 0.01) and cirrhosis at the baseline (P < 0.0001) as factors contributing to the development of HCC. Cumulative incidence rates of HCC during 10 years among carriers found with chronic hepatitis increased in parallel with the age at the baseline. Conclusion: Identification of HCV carriers in the general population and treating those indicated with IFN would help decrease the development of HCC and lift its medical, as well as economic, burdens off society.     

Rate-dependent anisotropic conduction property in the epicardial border zone of canine myocardial infarcts and its modification by moricizine

Summary We evaluated anisotropic conduction properties, different conduction velocities depending on fiber orientation, in normal and infarcted myocardium and the effects of moricizine on anisotropic conduction. Various cycle lengths of stimulation were applied to 15 mongrel dogs, and epicardial mapping was performed using a 96-channel mapping electrode. Moricizine was then administered to seven dogs and the same procedure was performed. Conduction velocities were calculated from these maps. Programmed electrical stimulations were performed before and after moricizine administration to induce ventricular arrhythmias. Before moricizine administration, a rate-dependent decrease in longitudinal conduction velocity was observed in the infarcted zone. Moricizine suppressed longitudinal conduction in the normal zone significantly at 300 msec pacing, but not at slower rates. Moricizine at a dose of 4 mg/kg, on the other hand, suppressed longitudinal conduction in the infarcted zone significantly at all pacing cycle lengths. The effect of moricizine on transverse conduction was inconsistent. In three dogs, sustained ventricular tachycardia (VT) was induced either before or after moricizine administration. The mean cycle length of sustained VT was prolonged from 202 msec to 291 msec after 4 mg/kg of moricizine. Thus, the changes in cycle length of ventricular tachycardia observed were most likely the result of slowing of conduction velocity, especially in the longitudinal direction, in the infarcted myocardium. We conclude that the electrophysiologic nature of the subacute ischemic model was modified by moricizine, leading to depression of the conduction velocity of longitudinal conduction and the inducibility of ventircular arrhythmias.     

Intraventricular dyssynchrony may play a role in the development of mitral regurgitation in dilated cardiomyopathy

BACKGROUND: The development of functional mitral regurgitation (MR) in dilated cardiomyopathy (DCM) has been attributed to altered left ventricular (LV) geometry and annular dilatation. We propose the hypothesis that intraventricular dyssynchrony may play a role in the development of MR in DCM. METHODS AND RESULTS: Tissue Doppler echocardiography was performed in 32 DCM patients to assess the time from the onset of the QRS complex to the peak systolic myocardial strain (Ts) at 2 segments adjacent to the anterolateral and posteromedial papillary muscles from a short axis view. The time difference corrected by the RR interval (DeltaTs/ radicalRR) was used to evaluate dyssynchrony of these segments. There was no difference in the QRS duration (103 +/- 29 ms versus 95 +/- 22 ms, P = .38) or the presence of left bundle branch block (39% versus 14 %, P = .25) between 18 patients with MR and 14 patients without MR. However, DeltaTs/ radicalRR was significantly increased in the patients with MR, compared with those without MR (104 +/- 67 ms versus 5 +/- 16 ms, P < .0001). Stepwise multiple regression analysis showed that DeltaTs/ radicalRR was independent contributing factor of MR. CONCLUSION: Dyssynchrony of myocardial segments adjacent to the papillary muscles may disturb synchronized closure of the mitral leaflets and cause MR in DCM.     

Deaths within 12 months after (125)I implantation for brachytherapy of prostate cancer: an investigation of radiation safety issues in Japan (2003-2010)

PurposeThe International Commission on Radiological Protection recommends removing the prostate before cremation if death occurs within 12 months after ¹²⁵I brachytherapy. However, the incidence of death within this time frame has not been robustly investigated in any country. The purpose this study was to investigate the incidence and cause of death and actions taken when death has occurred within 12 months after ¹²⁵I brachytherapy for prostate cancer in Japan.Methods and MaterialsData were extracted from the Japan Radioisotope Association database to investigate the total number of implantation cases, number of early deaths after implantation, cause of death, and postmortem actions between September 2003 and the end of June 2010 in Japan. Early death was defined as occurring within 12 months after ¹²⁵I brachytherapy for prostate cancer.ResultsDuring the study period, 15,427 patients underwent ¹²⁵I brachytherapy and 43 (0.28%) died within 12 months after implantation. For 37 of the 43 patients (86%), the brachytherapy source was retrieved together with the prostate gland at autopsy; however, autopsy could not be performed in six (14%) of the deceased patients. The largest proportion of early deaths was because of cerebrovascular or cardiovascular disease (17/43, 40%), followed by malignant tumor (15/43, 35%), and respiratory disease or infection (7/43, 16%).ConclusionsThe incidence of early deaths within 12 months after ¹²⁵I brachytherapy in Japan was 0.28%. In almost all cases, the brachytherapy sources were removed in the intact prostate before the body was cremated and stored appropriately.