Pharmacokinetic and pharmacodynamic simulation for the quantitative risk assessment of linezolid-associated thrombocytopenia.

WHAT IS KNOWN AND OBJECTIVE: Linezolid (LZD) may cause thrombocytopenia, which can result in discontinuation of treatment. In this study, the blood LZD trough concentration was estimated based on population pharmacokinetic (PK) parameters derived from two previously published models in the Japanese population to determine the rate of achieving the target trough value when the risk of thrombocytopenia is low and to clarify its relationship with the onset of thrombocytopenia. METHODS: This study included adult patients hospitalized at Shimane University Hospital, who received LZD treatment for at least 4 days from January 2010 to December 2017. Patients whose platelet count fell below 70% before LZD administration were categorized as the thrombocytopenic group. Patient PK parameters were calculated based on the population PK models described by Matsumoto et al. and Sasaki et al., and these parameters were designated A and B, respectively. Based on these parameters, the rate of achieving an LZD trough concentration of less than 8 µg/ml, which is the safety target achievement rate, was calculated using a random simulation for each patient. We further analysed the association between the incidence of thrombocytopenia and patient factors, including safety target achievement rate, through univariate, multivariate, and receiver operating characteristic (ROC) analyses. RESULTS AND DISCUSSION: Patients (n = 77) aged 72 ± 11 years and weighing 56.7 ± 10.9 kg, with a creatinine clearance (CLcr ) of 60.5 ± 47.2 ml/min and a cirrhosis prevalence of 9.1%, were analysed. All patients received LZD at a dose of 600 mg twice daily for a total of 10.9 ± 8.9 days. Univariate analyses revealed significant differences (p < 0.05) in the duration of LZD therapy, serum creatinine, creatinine clearance, LZD clearance, and the safety target achievement rate for parameters A and B between the thrombocytopenic and non-thrombocytopenic groups. A multivariate analysis of these factors stratified with the cutoff values obtained by ROC analysis revealed that the duration of LZD therapy and the safety target achievement rates for parameters A and B were significant factors (odds ratios for duration of LZD therapy: 7.436 [95% confidence interval (CI): 1.918-28.831] and 4.712 [95% CI: 1.567-14.163]; odds ratio for safety target achievement rate: 0.060 [95% CI: 0.016-0.232] and 0.167 [95% CI: 0.056-0.498] for parameters A and B, respectively). When the safety target achievement rates for patients treated with LZD were compared between the thrombocytopenic and non-thrombocytopenic groups, the safety target achievement rate was higher in the non-thrombocytopenic group in both the patients treated with LZD for less than 10 days and those for 10 days or more. Therefore, the safety target achievement rate estimated by the PK/PD simulation may represent to be an important index for risk assessment of LZD-induced thrombocytopenia. WHAT IS NEW AND CONCLUSION: The risk of LZD-induced thrombocytopenia, which increased with the duration of LZD therapy, may be predicted using the safety target achievement rate obtained by the blood concentration simulation.

Effect of Timing of Proton Pump Inhibitor Administration on Acid Suppression.

BACKGROUND: Esomeprazole has been reported to show a strong acid suppression following preprandial as compared to postprandial administration, though no known study has compared the acid suppressing effects of other proton pump inhibitors between those administrations. The aim of this study was to compare intragastric pH levels following pre- and postprandial administrations of rabeprazole and esomeprazole. METHODS: In 15 Helicobacter pylori-negative healthy volunteers, we measured intragastric pH after 7 days of pre- and postprandial administrations of rabeprazole (10 mg) or esomeprazole (20 mg) using a 5-way crossover design. RESULTS: Preprandial administration of esomeprazole showed stronger acid suppression than postprandial administration. The values for percent time at pH >4.0 over a 24-hour period increased from 45.3% with postprandial administration of esomeprazole to 54.4% with preprandial administration, while the percent time at pH >4.0 during daytime was increased to a greater extent from 51.4 to 66.5% with preprandial administration (p = 0.05). On the other hand, the acid suppressing effect of rabeprazole was not influenced by the timing of administration. CONCLUSIONS: The acid suppressing effect of esomeprazole is influenced by administration timing. In contrast, the acid suppressing effect of rabeprazole is not augmented by preprandial administration.

Evaluation of a pharmacokineticpharmacodynamic approach using software to optimize the carbapenem antibiotic regimen.

OBJECTIVE: Meropenem (MEPM) and doripenem (DRPM), whose antipseudomonal activity is more potent than that of other carbapenem antimicrobials, were used in the study. Monte Carlo simulation of drug concentrations was performed to develop an administration plan for MEPM and DRPM that takes into account the pharmacokinetics (PK)-pharmacodynamics (PD) of MEPM and DRPM and the renal function of each patient. Drug administration plans were proactively applied to patients with pneumonia to determine the usefulness of the method by assessing treatment efficacy and safety. METHODS: Patients with healthcareassociated pneumonia and an indication for MEPM or DRPM chemotherapy underwent drug administration in accordance with the MEPM and DRPM treatment plan developed by the PK-PD software applications. The primary efficacy endpoints were the clinical and bacteriological efficacy of the drugs agains pneumonia. The safety of the antimicrobials was assessed based on abnormal laboratory findings and the seizure disorders in accordance with the criteria for safety evaluation of antimicrobial agents. RESULTS: This study examined 12 and 11 patients in the MEPM and DRPM group, respectively; however, 3 DRPM patients were excluded due to the administration of anti-methicillin-resistant Staphylococcus aureus drugs after the initiation of DRPM treatment. MEPM and DRPM drug administration was determined to be safe and effective in all patients. CONCLUSIONS: The present results suggest that the Monte Carlo simulation-based PK-PD software is an effective tool for planning individualized antimicrobial chemotherapy with carbapenem in accordance with the PK-PD theory of antimicrobials. It is also possible to propose safe and effective drug administration plans for patients with healthcare-associated pneumonia.

Nephrotoxicity induced by piperacillin­tazobactam in late elderly Japanese patients with nursing and healthcare associated pneumonia.

This study aimed to clarify the efficacy, safety, and pharmacokinetics of piperacillin­tazobactam (PIPC­ TAZ) in late elderly Japanese patients. This is the first antimicrobial pilot study in late elderly patients with nursing and healthcare associated pneumonia. After PIPC­TAZ administration, PIPC concentrations in plasma were measured chromatographically and the pharmacokinetic parameters were estimated. Efficacy, safety, and bacteriological evaluations were also carried out. The mean age was 85.0 years old and most of the patients were late elderly. Chest X-rays, body temperature, white blood cell count, and C reactive protein all improved significantly, and a high efficacy ratio of 90.9% was observed. Serious nephrotoxicity was observed in 4 cases (18.2%) after administration of PIPC­TAZ. Creatinine clearance (meanS.D.) measured before PIPC­TAZ therapy was significantly lower in the nephrotoxicity group (32.54.4 mL/min) than in the non-nephrotoxicity group (46.116.7 mL/min), although the ages were not different between the 2 groups. In the pharmacokinetic parameters for PIPC, total clearance was slightly lower in the nephrotoxicity group than in the non-nephrotoxicity group. However, no significant difference was observed in plasma PIPC levels between the 2 groups. In patients with renal impairment, especially with a creatinine clearance of <40 mL/ min, renal impairment was found to be an influencing factor for severe nephrotoxicity following PIPC­TAZ administration. In conclusion, the results suggest that physicians should pay close attention in order to avoid possible toxicity, and that deliberate administration planning and careful follow-up are required in late elderly patients with comprised organ dysfunction.

Evaluation of the efficacy and safety of biapenem against pneumonia in the elderly and a study on its pharmacokinetics.

Although biapenem is used in the treatment of pneumonia, the clinical data on elderly patients are yet insufficient. Therefore, the purpose of this study was evaluating the efficacy and safety of biapenem against pneumonia in the elderly and its pharmacokinetics. The subjects were patients 65 years of age or older with pneumonia. Biapenem (300 mg) was administered once to three times per day. For some cases, the drug concentrations in plasma were measured chronologically. The clinical efficacy was evaluated in reference to the improvement in subjective symptoms and objective opinion. The primary outcome was efficacy rate at the end of treatment. Biapenem was effective in 17 of 20 subject cases (85.0 %). Regarding safety, although 4 cases experienced hepatic dysfunction and 1 case had nausea, these effects were not severe in all cases and administration was continued. There was no deterioration of renal function associated with biapenem. In 13 cases in which the trough value of biapenem was measured, there were no unacceptable side effects and the trough values were generally low. It is believed that biapenem (300 mg once to three times a day), even when taken by elderly people, does not accumulate and that the dosage is safe and appropriate. The changes in the predicted concentrations calculated with the pharmacokinetic-pharmacodynamic (PK-PD) software, which is based on previously reported population pharmacokinetic parameters, and those in the measured concentrations approximately matched. It is useful to plan biapenem administration using the PK-PD software when performing antibiotic chemical treatment.

Comparison of hemagglutination inhibition assay and enzyme immunoassay for determination of mumps and rubella immune status in health care personnel.

BACKGROUND: Screening tests are available to determine immunity to vaccine-preventable diseases, such as mumps and rubella. We aimed to define better assay for detecting immune status of health care personnel to vaccine-preventable diseases. METHODS: Mumps and rubella antibodies of health care personnel at Shimane University Hospital were examined by hemagglutination inhibition assay (HI), comparing with those by enzyme immunoassay (EIA). RESULTS: A total of 910 sera from health care personnel were tested. There was poor correlation between HI and EIA in detecting mumps antibodies with correlation coefficient values (r) = 0.190 (P < 0.001), but in rubella antibodies HI and EIA were relatively well correlated (r = 0.930, P < 0.001). Seropositivity rate of HI versus EIA was found to be 65.7 versus 93.2, and 89.5 versus 86.5% for mumps and rubella, respectively. As compared with EIA, HI identified sixfold larger seronegative subjects in mumps. Moreover, in mumps, 88.8% of seronegative subjects detected by HI were seropositive by EIA, while 3.7% of seropositive subjects detected by HI were seronegative by EIA. In rubella, 2.1% of seronegative subjects detected by HI were seropositive by EIA, and 1.7% of seropositive by HI was seronegative by EIA. CONCLUSION: Considerable difference between HI and EIA in determining immune status of health care personnel to mumps and rubella suggests beneficial use of EIA for the identification of accurate susceptible personnel who subsequently undergo an effective vaccination programs. Seroprevalence survey of health care personnel by using appropriate assay is essential for prevention and infection control strategies in health care settings.

Long-term stability of over-the-counter cuffless blood pressure monitors: a proposal.

Blood pressure is an important cardiovascular parameter. Currently, the cuff-based sphygmomanometer is a popular, reliable, measurement method, but blood pressure monitors without cuffs have become popular and are now available without a prescription. Blood pressure monitors must be approved by regulatory authorities. Current cuffless blood pressure (CL-BP) monitors are not suitable for at-home management and prevention of hypertension. This paper proposes simple criteria for over-the-counter CL-BP monitoring. First, the history of the sphygmomanometer and current standard blood pressure protocol are reviewed. The main components of CL-BP monitoring are accuracy during the resting condition, accuracy during dynamic blood pressure changes, and long-term stability. In this proposal we recommend intermittent measurement to ensure that active measurement accuracy mirrors resting condition accuracy. A new experimental protocol is proposed to maintain long-term stability. A medically approved automated sphygmomanometer was used as the standard device in this study. The long-term accuracy of the test device is based on the definition of propagation error, i.e., for an oscillometric automated sphygmomanometer (5 ± 8 mmHg) ± the error for the test device static accuracy (-0.12 ± 5.49 mmHg for systolic blood pressure and - 1.17 ± 5.06 mmHg for diastolic blood pressure). Thus, the long-term stabilities were - 3.38 ± 7.1 mmHg and - 1.38 ± 5.4 mmHg, which satisfied propagation error. Further research and discussion are necessary to create standards for use by manufacturers; such standards should be readily evaluated and ensure high-quality evidence. Supplementary information: The online version contains supplementary material available at 10.1007/s12553-023-00726-6.

[Usefulness of phage ORF typing, a rapid genotyping method as a molecular and epidemiological method for detecting methicillin resistant Staphylococcus aureus].

Surveillance is very important for preventing the nosocomial spread of methicillin-resistant Staphylococcus aureus (MRSA), and the pulsed-field gel electrophoresis (PFGE) method has long been used to identify the infection source and route as a molecular and epidemiological genotyping method. However, the use of the method in routine clinical laboratory measurements is difficult due to its complicated procedures. Since a molecular and epidemiological genotyping kit based on the POT (Phage Open-reading Frames Typing) method has been developed, we examined 192 MRSA isolates newly detected from inpatients in our hospital in 2010 in order to investigate the usefulness of POT for surveying outbreaks of MRSA. Among the 192 isolates 118 were suspected of nosocomial spread by the previous method, which defined a MRSA detection at more than 48 hours after admission as a nosocomial spread. The POT method was introduced at our laboratory in 2010, and we were able to recognize 38 patients as having strongly suspected nosocomial MRSA infection with the POT method taking into consideration the infection situation, such as places (wards and transfer) and time (date of admission and date of collected samples). Our Infection Control Division was confidently able to demonstrate the current condition of the nosocomial spread by providing the results to the clinical staff, who were also able to practice infection control confidently. We concluded that the POT method was very useful and convenient for investigating MRSA isolates and evaluating collected data because no particular analysis other than the digitizing electrophoretic pattern method was necessary.

[Assessment of Renal Function and Simulation Using Serum Cystatin-C in an Elderly Patient with Uncontrollable Plasma Vancomycin Levels Due to Muscular Dystrophy: A Case Report].

Herein, we describe a case of an elderly patient with muscular dystrophy for whom control of the plasma vancomycin (VCM) concentration proved difficult when he developed a catheter-related bloodstream infection. The pharmacist initially carried out therapeutic drug monitoring using an estimate of the creatinine clearance (CLcr) level, which was based on the serum creatinine (SCr) and serum cystatin-C (CysC) levels, but was ultimately unable to control the plasma VCM concentration. Therefore, the plasma VCM concentration was predicted ex post facto using population pharmacokinetic parameters as a covariate; that is, directly including the glomerular filtration rate (GFRCysC) estimated from the CysC level, which is not affected by the muscle mass. As a result, the estimated VCM concentration was closer to the actual concentration than that predicted using CLcr. Furthermore, the results of examining the predictive accuracy according to the assessment of renal function at the time of initial VCM administration suggested that estimation of the trough concentration using GFRCysC might be useful in elderly patients with muscular dystrophy.

Pharmacokinetics of edoxaban in EGFR-mutated non-small cell lung cancer patients with venous thromboembolism.

BACKGROUND: The risk of venous thromboembolism (VTE) is increased 7-fold in patients with cancer than in those without. Low-molecular-weight heparin is the standard treatment for cancer-associated VTE. Direct oral anticoagulants (DOACs) are not inferior to low-molecular-weight heparin with respect to the general outcome of recurrent VTE. Warfarin is associated with a risk of bleeding when used in combination with gefitinib or erlotinib which are epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs). It is unclear, however, whether combination treatments with EGFR-TKIs and DOACs pose the same risk. We aimed to identify anticancer drugs and anticoagulants that can be used safely in combination, as accompanying research to an observational study on VTE incidence rates in lung cancer patients (Rising-VTE/NEJ037 study). METHODS: Twelve patients receiving EFGR-TKI monotherapy and VTE treatment were enrolled. Blood samples were collected in time series after the first dose of edoxaban, and further samples were collected within 8-15 days after administering EGFR-TKIs. The pharmacokinetics (PK) of edoxaban were analyzed using a non-compartmental model. RESULTS: Edoxaban concentrations (30 mg once daily) were measured in eight patients. PK analyses showed no significant differences before and after co-administration of EGFR-TKIs (gefitinib, erlotinib, and afatinib). CONCLUSIONS: Our findings indicate that the PK of edoxaban was not considerably affected by co-administration of EGFR-TKIs (gefitinib, erlotinib, and afatinib).

Population Pharmacokinetic Modeling and Pharmacodynamic Target Attainment Simulation of Piperacillin/Tazobactam for Dosing Optimization in Late Elderly Patients with Pneumonia.

The aim of this study was to develop a population pharmacokinetic model for piperacillin (PIPC)/tazobactam (TAZ) in late elderly patients with pneumonia and to optimize the administration planning by applying pharmacokinetic/pharmacodynamic (PK/PD) criteria. PIPC/TAZ (total dose of 2.25 or 4.5 g) was infused intravenously three times daily to Japanese patients over 75 years old. The plasma concentrations of PIPC and TAZ were determined using high-performance liquid chromatography and modeled using the NONMEM program. PK/PD analysis with a random simulation was conducted using the final population PK model to estimate the probability of target attainment (PTA) profiles for various PIPC/TAZ-regimen-minimum-inhibitory-concentration (MIC) combinations. The PTAs for PIPC and TAZ were determined as the fraction that achieved at least 50% free time > MIC and area under the free-plasma-concentration-time curve over 24 h ≥ 96 µg h/mL, respectively. A total of 18 cases, the mean age of which was 86.5 ± 6.0 (75-101) years, were investigated. The plasma-concentration-time profiles of PIPC and TAZ were characterized by a two-compartment model. The parameter estimates for the final model, namely the total clearance, central distribution volume, peripheral distribution volume, and intercompartmental clearance, were 4.58 + 0.061 × (CLcr - 37.4) L/h, 5.39 L, 6.96 L, and 20.7 L/h for PIPC, and 5.00 + 0.059 × (CLcr - 37.4) L/h, 6.29 L, 7.73 L, and 24.0 L/h for TAZ, respectively, where CLcr is the creatinine clearance. PK/PD analysis using the final model showed that in drug-resistant strains with a MIC > 8 µg/mL, 4.5 g of PIPC/TAZ every 6 h was required, even for the patients with a CLcr of 50-60 mL/min. The population PK model developed in this study, together with MIC value, can be useful for optimizing the PIPC/TAZ dosage in the over-75-year-old patients, when they are administered PIPC/TAZ. Therefore, the findings of present study may contribute to improving the efficacy and safety of the administration of PIPC/TAZ therapy in late elderly patients with pneumonia.

[Pharmaceutical analysis and clinical efficacy of Kampo medicine, maoto, extract suppository against pediatric febrile symptoms].

A traditional Chinese herbal medicine, Kampo medicine, maoto, has been widely used in the treatment of febrile symptoms caused by viral infection. This herbal extract granule for oral use, however, is not well accepted by infants or young children due to its unpleasant taste and odor. Therefore, we prepared Kampo medicine, maoto, suppository and investigated the pharmaceutical and clinical efficacy of the suppository. Kampo medicine, maoto, granules were micro-pulverized and homogeneously dispersed into Hosco-H15 to prepare suppositories containing 0.25 to 1.0 g herbal extract by the conventional fusion method. Content of l-ephedrine, an index compound of Kampo medicine, maoto, in the extract granules and suppositories was determined by using a high performance liquid chromatographic method. Physicochemical experiments revealed that the suppository containing 0.5 g herbal extract had the most suitable melting point of 34 degrees C. Contents of l-ephedrine in the suppository were constant, 93-96% of those in the same amount of the extract granules in different three lots. Upper and lower portions of the suppository had the same content of l-ephedrine. The suppository maintained more than 95% of l-ephedrine content through 6 months at 4 degrees C, room temperature and 40 degrees C, although maldistribution of the extract constituent was observed after storage at 40 degrees C. The suppository was administered to 21 pediatric febrile patients at a dose of 1/3 to 2 full pieces depending on their body weight and physical status. Significant reduction (p<0.001) of body temperature from 39.5 to 37.5 degrees C without serious adverse effects was observed in 17 patients who were monitored the clinical effects on the febrile symptoms. In conclusion, Kampo medicine, maoto, suppository was found to satisfy the physicochemical quality and quantity standards as well as to be clinically applicable to neonates, infants and children with viral febrile symptoms without any adverse effects.

Molecular Mechanism of Matrine from Sophora alopecuroides in the Reversing Effect of Multi-Anticancer Drug Resistance in K562/ADR Cells.

Multidrug resistance is the main obstacle to current chemotherapies. In this study, we evaluated the reversing effect of matrine, the principal alkaloid derived from Sophora alopecuroides, on chemoresistant leukemia K562/ADR cells. Matrine in a range of the nontoxic concentration was employed in the whole study. IC50s of cancer medicines were tested using WST-8 assay. Drug export and apoptotic rates were examined using flow cytometry. The mRNA and protein expressions were quantified by quantitative real-time PCR and western blotting, respectively. Our data indicated that matrine had potent reversal properties augmenting cytotoxicity of cancer medicines on K562/ADR cells as well as apoptotic rates induced by doxorubicin. Moreover, matrine inhibited drug-exporting activity and expression of ATP-binding cassette subfamily B member 1 (ABCB1) on both mRNA and protein levels. That might result from inhibited NF-kappa B activation, which also led to restored intrinsic apoptosis. These findings suggest that matrine in the nontoxic concentration can suppress ABCB1 drug transport and facilitate the intrinsic apoptosis pathway through the inhibiting effect on NF-kappa B and has the potential to become an efficient sensitizer for anticancer drug resistance.

Japanese antimicrobial consumption surveillance: First report on oral and parenteral antimicrobial consumption in Japan (2009-2013).

No reliable national antimicrobial consumption data have been available in Japan. The Japanese antimicrobial consumption surveillance (JACS) project started to collect data nationwide on antimicrobial consumption. This paper provides the first sales data from the JACS project on oral and parenteral antimicrobial consumption in Japan as well as the trends for the years from 2009 to 2013. The population-weighted total consumption was expressed as defined daily doses (DDDs) per 1000 inhabitants per day (DID). The value of DID increased from 14.7 in 2009 to 15.8 in 2013. Notably, oral antimicrobials accounted for 92.6% (mean of 2009, 2011 and 2013) of total consumption. Oral third-generation cephalosporins, macrolides and fluoroquinolones accounted for 77.1% (mean of 2009, 2011 and 2013) of oral consumption. Consumption of antimicrobials has increased during the years 2009 and 2013 regardless of the dosage form. This is the first report regarding the population-weighted consumption of oral and parenteral antimicrobials in Japan during the years 2009 and 2013. These results provide useful information for combating the menace of antimicrobial resistance in Japan.

[Effects of Chinese herbal medicines on intestinal drug absorption].

Sho-saiko-to (Xiao-Chai-Hu-Tang), one of the major traditional Chinese medicines, has been frequently prescribed with other synthetic or biotechnological drugs for the treatment of various acute or chronic diseases in Japan, and thus it is important to understand the interactions between Sho-saiko-to and coadministered drugs. This paper reviews the effects of Sho-saiko-to on the pharmacokinetics and pharmacodynamics of concomitant drugs in the gastrointestinal tract. Sho-saiko-to slightly hastens the gastrointestinal absorption of the sulfonylurea compound tolbutamide. Furthermore, it is considered that the increase in the gastrointestinal absorption rate by Sho-saiko-to may potentiate the hypoglycemic effects of tolbutamide in the early period after oral administration. Sho-saiko-to can facilitate the epithelial membrane permeability of tolbutamide at an early phase across the rat jejunum in situ and Caco-2 cell monolayers. It is also suggested that Sho-saiko-to enhances the energy-dependent transport of tolbutamide and has an inhibitory effect on the passive paracellular transport of tolbutamide in Caco-2 cells. This result might be related to the accelerated in vivo absorption rate of tolbutamide by concomitant dosing with Sho-saiko-to in rats. In addition, Sho-saiko-to has inhibitory effects on the efflux pump mediated by MDR1, and it appears that the crude constituents in Glycyrrhizae radix, glycyrrhizic acid and liquiritin, contribute to MDR1 suppression.

Transepithelial permeation of tolbutamide across the human intestinal cell line, Caco-2.

Sulfonylurea hypoglycemic agents have interindividual variability in the gastrointestinal absorption rate. However, the absorption mechanism at the intestinal epithelium has not yet been clarified. To elucidate contribution of the specific mechanism for transepithelial transport of sulfonylureas, the apical-to-basolateral and basolateral-to-apical transport studies of tolbutamide were carried out using Caco-2 cell monolayers cultured on the polycarbonate membrane. The transported amounts of the substrate were measured by HPLC to estimate the apparent permeability coefficients (P(app)). In the apical-to-basolateral flux, the transport activity of tolbutamide was facilitated when the pH of the apical medium was more acidic than the basolateral one. ATP-depletion decreased the P(app) of tolbutamide. The kinetic analysis of the permeation rate indicated that the saturable process largely contributed to the tolbutamide flux. The P(app) of tolbutamide was lowered by an ionophore and monocarboxylic acids, while dicarboxylic acids and the inhibitor for the anion exchanger had no effect. In addition, mutual inhibition with benzoic acid was observed in transepithelial transport of tolbutamide. On the other hand, the permeation rate of tolbutamide from the basolateral to apical side was concentration-independent and neither affected by metabolic inhibitors, probenecid nor inhibitors for P-glycoprotein. In conclusion, these results suggest that apical-to-basolateral transport of tolbutamide across the Caco-2 cell monolayers is mediated by the pH-dependent specific system, presumably shared with other organic anions such as benzoic acid.

Bcl-2 family inhibition sensitizes human prostate cancer cells to docetaxel and promotes unexpected apoptosis under caspase-9 inhibition.

Docetaxel (DTX) is a useful chemotherapeutic drug for the treatment of hormone-refractory prostate cancer. However, emergence of DTX resistance has been a therapeutic hurdle. In this study, we investigated the effect of combining DTX with Bcl-2 family inhibitors using human prostate cancer cell lines (PC3, LNCaP, and DU145 cells). PC3 cells were less sensitive to DTX than were the other two cell lines. In contrast to ABT-199, which inhibits Bcl-2 and Bcl-w, both ABT-263 and ABT-737, which inhibit Bcl-2, Bcl-xL, and Bcl-w, significantly augmented the antitumor effect of DTX on PC3 cells. ABT-263 also enhanced the antitumor effect of DTX on a DTX-resistant PC3 variant cell line. The antitumor effect of ABT-263 was due mainly to its inhibitory effect on Bcl-xL. In a xenograft mouse model, DTX and ABT-737 combination therapy significantly inhibited PC3 tumor growth. Interestingly, although ABT-263 activated caspase-9 in PC3 cells, inhibition of caspase-9 unexpectedly promoted ABT-263-induced apoptosis in a caspase-8-dependent manner. This augmented apoptosis was also observed in LNCaP cells. These findings indicate that Bcl-xL inhibition can sensitize DTX-resistant prostate cancer cells to DTX, and they reveal a unique apoptotic pathway in which antagonism of Bcl-2 family members in caspase-9-inhibited prostate cancer cells triggers caspase-8-dependent apoptosis.

Comparative analysis of a complement fixation assay and enzyme immunoassay to determine the seroprevalence of measles and varicella in a survey of healthcare workers.

OBJECTIVE: Seroprevalence surveys of healthcare workers for vaccine-preventable diseases, including measles and varicella, are essential for disease prevention and infection control programmes. The purpose of this study was to compare the complement fixation (CF) assay and an enzyme immunoassay (EIA) to determine the prevalence of immunoglobulin G antibodies directed against measles and varicella viruses in healthcare workers. METHODS: Antimeasles and antivaricella antibody titres were measured simultaneously in serum samples from healthcare workers employed at a Japanese university hospital, using the CF assay and an EIA. RESULTS: Serum samples were obtained from 898 healthcare workers. Seropositivity rates determined using the CF assay and EIA were 67.8% versus 94.0%, respectively, for measles, and 83.2% versus 97.6% for varicella. Compared with EIA, a nine- and 22-fold higher number of seronegative subjects was identified by the CF assay for measles and varicella, respectively. CONCLUSION: Differences between the CF assay and EIA in detecting seronegative or seropositive healthcare workers for measles and varicella suggest that undertaking a seroprevalence survey using an EIA, rather than a CF assay, would more accurately determine susceptibility to vaccine-preventable diseases, in healthcare settings.

Topical dexamethasone-cyclodextrin microparticle eye drops for diabetic macular edema.

PURPOSE: To test the safety and efficacy of topical 1.5% dexamethasone aqueous eye drops with cyclodextrin microparticles for diabetic macular edema (DME). METHODS: Nineteen eyes of 19 consecutive patients with DME were administered dexamethasone-cyclodextrin eye drops three or six times a day for 4 weeks and then observed for 4 weeks without treatment. Visual acuity, intraocular pressure, and spectral domain optical coherent tomography-measured central macular thickness recordings at weeks 0 (baseline), 4, and 8. These parameters were compared using Bonferroni-corrected paired t-tests. RESULTS: At weeks 0, 4, and 8, logMAR visual acuity (mean ± SD) was 0.52 ± 0.41, 0.37 ± 0.40 (P = 0.0025 vs. baseline), and 0.45 ± 0.41, respectively; central macular thickness (µm) was 512 ± 164, 399 ± 154 (P = 0.0016 vs. baseline), and 488 ± 172 (P = 0.0116 versus week 4), respectively; and intraocular pressure (mm Hg) was 15.2 ± 3.1, 17.4 ± 4.2 (P = 0.0015 vs. baseline) and 15.8 ± 4.0, respectively. At week 4, in 12 (63%) of 19 eyes, central macular thickness had decreased more than 10%, and the mean change was -20% (-65% to +10%). In 14 of 19 eyes (74%) visual acuity (logMAR) had improved more than 0.1 at week 4. No subjects showed severe adverse effects related to the eye drops. CONCLUSIONS: Based on this short pilot study, topical dexamethasone-cyclodextrin eye drops are well tolerated, decrease central macular thickness, and improve visual acuity in DME. The results encourage comparative studies between dexamethasone cyclodextrin microparticle eye drops and other treatments for DME. (http://www.umin.ac.jp/ctr number, UMIN000001790.).

Change in tolbutamide permeability in rat jejunum and Caco-2 cells by Sho-saiko-to (Xiao Chai Hu Tang), a Chinese traditional medicine.

OBJECTIVES: This study was designed to investigate the effects of Sho-saiko-to (Xiao Chai Hu Tang), a Chinese traditional medicine, on the membrane permeability of tolbutamide in the intestinal tract. We carried out an in-situ loop study with rat jejunum and a transport study with Caco-2 cell monolayers. METHODS: In the in-situ loop study, absorption clearance of tolbutamide was estimated from the drug concentrations in the loop and plasma. The apical-to-basolateral and basolateral-to-apical transport of tolbutamide and d-mannitol, a paracellular transport marker, was assessed using Caco-2 cell monolayers cultured on a polycarbonate membrane. KEY FINDINGS: The absorption clearance of tolbutamide was enhanced by a concomitant dose of Sho-saiko-to over 10 min in the rat in-situ loop. Sho-saiko-to increased the apical-to-basolateral transport of tolbutamide, whereas the basolateral-to-apical transport of this drug was reduced by Sho-saiko-to. On the other hand, in both directions the P(app) of d-mannitol was reduced by the presence of Sho-saiko-to. Furthermore, the apical-to-basolateral transport of tolbutamide in ATP-depleted Caco-2 cells was diminished by Sho-saiko-to. These findings suggest that Sho-saiko-to can facilitate the epithelial membrane permeability of tolbutamide across the rat jejunum in-situ and Caco-2 cell monolayers. Since Sho-saiko-to suppressed the passive transport of tolbutamide from the apical-to-basolateral side, enhanced permeability may be related to effects of Sho-saiko-to on the energy-dependent transport of tolbutamide in the intestine. CONCLUSIONS: Our findings suggest that Sho-saiko-to might facilitate the energy-dependent transport of tolbutamide across the rat jejunum in-situ and Caco-2 cell monolayers.