Preparation and antibacterial evaluation of silver-doped zirconia for enhanced dental restoration performance.

Because of its superior strength, esthetic properties, and excellent biocompatibility, zirconia is preferred for dental prosthetic such as crowns and bridges. However, zirconia crowns and bridges are susceptible to secondary caries owing to margin leakage. Silver is a well-known antibacterial agent, making it a desirable additive to zirconia crowns and bridges for secondary caries prevention. This study focuses on imparting zirconia composite with antibacterial properties to enhance its protective capacity in dental restorations. We used the sol-gel method to dope Ag into zirconia. Silver-doped zirconia powders were prepared at Zr:Ag molar ratios of 100:0,100:0.1, 100:0.5, 100:1, 100:3, and 100:5 (respective samples denoted as Ag-0, Ag-0.1, Ag-0.5, Ag-1, Ag-3, and Ag-5) and were subjected to firing at various temperatures (400 °C-1000 °C). We performed x-ray diffraction to investigate the crystal phase of these powders and x-ray fluorescence and field emission scanning electron microscopy to analyze their elemental composition and surface morphology, respectively. Moreover, we performed spectrophotometry to determine theL*a*b* color values, conducted dissolution tests, and quantified the Ag content through inductively coupled plasma optical emission spectroscopy. In addition, we studied the antibacterial activity of the samples. Analyses of the samples fired at ⩽600 °C revealed a predominantly white to grayish-white coloration and a tetragonal crystal phase. Firing at ⩾700 °C resulted in gray or dark gray coloration and a monoclinic crystal phase. The Ag content decreased after firing at 900 °C or 1000 °C. Ag-0.5 and above exhibited antibacterial activity against bothEscherichia coliandStaphylococcus aureus. Therefore, the minimum effective silver-doped zirconia sample was found to be Ag-0.5. This study allows the exploration of the antimicrobial potential of silver-doped zirconia materials in dental applications such as prosthdontical lining materials, promoting the development of innovative restorations with protective capacity against secondary caries.

Adsorption of oral antibacterial agents on zirconia surfaces with different crystal systems.

Zirconia ceramics are widely used as dental prosthetics owing to their high biocompatibility, excellent mechanical strength, and aesthetic properties similar to color tones of natural teeth. However, there exists a growing demand for the facile attachment of antibacterial properties in long-term dental restoration. Thus, in this study, we evaluated the adsorption ability of cetylpyridinium chloride (CPC) and benzalkonium chloride (BKC)-quaternary amines widely used as antibacterial substances in commercial toothpaste and other oral care products-onto zirconia surfaces with tetragonal and monoclinic crystal structures. Although tetragonal zirconia has been widely used in dental prosthetic materials such as crowns etc., monoclinic zirconia has also been used under oral conditions because of long-term implantation. When antibacterial molecule loading on zirconia powders under simulated oral conditions, it was revealed that monoclinic zirconia adsorbed approximately five times more CPC and BKC per unit area compared with that of tetragonal zirconia. Moreover, in tetragonal zirconia, the adsorption amounts of both CPC and BKC increased slightly with growing Y2O3 content as a stabilizer. This phenomenon was attributable to the formation of complexes between rare earth elements (REE) such as Y2O3 in zirconia and quaternary amines such as CPC and BKC. In this study, the antibacterial molecular adsorption ability of dental zirconia was observed, and new advantages of zirconia in dental applications were discovered.

Naldemedine-induced perforation of a diverticulum in the sigmoid colon of a patient with opioid-related constipation: a case report.

BACKGROUND: Naldemedine is an orally available peripherally acting µ-opioid receptor antagonist approved to treat opioid-induced constipation (OIC). It is contraindicated for patients with known or suspected gastrointestinal obstruction to protect against naldemedine-induced perforation. Here, we report a clinical case of suspected perforation of a diverticulum in the sigmoid colon associated with naldemedine. CASE PRESENTATION: The patient was a 65-year-old man with a history of oral cancer who had been prescribed oxycodone (20 mg/day) for cancer pain. On day 0, the patient started naldemedine 0.2 mg once daily before bedtime for OIC. The dose of oxycodone was increased for pain control up to 60 mg/day. On day 35 of naldemedine treatment, the patient developed fever and abdominal pain, and his frequency of defecation had decreased. Initial laboratory results showed a C-reactive protein (CRP) level of 28.5 mg/dL and white blood cell (WBC) count of 13,500/µL. On day 37, the patient still had tenderness in his lower abdomen. Abdominal computed tomography revealed free air in the abdominal cavity suggesting an intestinal perforation. A Hartmann procedure was performed. Histopathological findings showed numerous diverticula in the sigmoid colon, some of which were perforated. CONCLUSIONS: These results suggest that the effects of OIC may have compressed the intestinal tract, which was followed by naldemedine-activation of peristalsis, which led to the onset of intestinal perforation. In patients with pre-existing diverticular disease, we should monitor for increased WBC counts and CRP levels after the initiation of treatment with naldemedine, and consider performing appropriate tests early in the event of abdominal complaints.

Relevance of plasma lenvatinib concentrations and endogenous urinary cytochrome P450 3A activity biomarkers in clinical practice.

Lenvatinib (LEN), a multitarget tyrosine kinase inhibitor used in various cancer treatments, is mainly metabolized by cytochrome P450 3A (CYP3A) enzymes. The importance of therapeutic drug monitoring (TDM) in patients administered LEN has been proposed. Although some biomarkers of endogenous CYP3A activity have been reported, their utility in dosage adjustments has not been well evaluated. This study investigated the correlation between plasma LEN concentrations and endogenous urinary CYP3A biomarkers in clinical practice. Concentrations of plasma LEN (N = 225) and CYP3A biomarkers (cortisol, 6ß-hydroxycortisol, deoxycholic acid, and 1ß-hydroxydeoxycholic acid) in urine (N = 214) from 20 patients (hepatocellular carcinoma, N = 6; thyroid cancer, N = 3; endometrial cancer, N = 8; and renal cell carcinoma, N = 3) collected for consultation for up to 1 year were evaluated using liquid chromatography-tandem mass spectrometry. Moreover, plasma trough LEN concentrations were predicted using a three-compartment model with linear elimination for outpatients administered LEN before sample collection. Moderate correlations were observed between the quantified actual concentrations and the predicted trough concentrations of LEN, whereas there was no correlation with endogenous urinary CYP3A biomarkers. The utility of endogenous urinary CYP3A biomarkers could not be determined. However, TDM for outpatients administered orally available medicines may be predicted using a nonlinear mixed effect model (NONMEM). This study investigated the utility of endogenous urinary CYP3A biomarkers for personalized medicine and NONMEM for predicting plasma trough drug concentrations. These findings will provide important information for further clinical investigation and detailed TDM.

Case report of QT interval prolongation induced by anamorelin in an obese patient with non-small cell lung cancer.

BACKGROUND: Anamorelin, a drug to treat cancer cachexia, binds to ghrelin receptors and improves body weight and appetite. In clinical trials in Japan, patients experienced a 10.7% frequency of stimulant conduction system depression as a severe side effect. Although rare, anamorelin sometimes causes fatal arrhythmias. Because patients with cancer cachexia are often underweight, data on the safety of anamorelin in obese patients are lacking. We report a case of QT interval prolongation after anamorelin administration to an obese patient with non-small cell lung cancer. CASE PRESENTATION: A female patient with a body mass index of 30 kg/m2 underwent immunotherapy for lung adenocarcinoma. She presented with severe weight loss, anorexia, and fatigue. She had no history of heart disease. On day 12, after administration of anamorelin 100 mg once daily, the patient developed nausea, diarrhea, and anorexia, which were considered cancer immunotherapy-induced immune-related adverse events, and she was admitted to the hospital. An electrocardiogram (ECG) on admission showed a QTc interval of 502 ms. On admission, her hepatic function was Child-Pugh class B, and anamorelin was discontinued the next day. On day 3 after anamorelin discontinuation, the QTc interval was prolonged by up to 557 ms, then decreased to 490 ms on day 6, and improved to 450 ms on day 16. Re-administration of anamorelin was avoided. CONCLUSIONS: When administering anamorelin to obese patients, we should be aware of the potential for stimulatory conduction system depression, as in underweight patients. Therefore, we should monitor patients by ECG from the early stages of anamorelin administration. Anamorelin is lipophilic, and its volume of distribution is increased in obese patients. Consequently, obese patients may continue to have QT interval prolongation after discontinuation of anamorelin, requiring long-term side-effect monitoring.

Plasma Venetoclax Concentrations in Patients with Acute Myeloid Leukemia Treated with CYP3A4 Inhibitors.

Venetoclax (VEN) is used in patients with acute myeloid leukemia (AML) and is primarily metabolized by CYP3A4, a major drug-metabolizing enzyme. Patients with AML simultaneously administered VEN and CYP3A4 inhibitors require a more appropriate management of drug-drug interactions (DDIs). Here, we report two cases of patients with AML (54-year-old man and 22-year-old woman) administrated VEN and CYP3A4 inhibitors, such as posaconazole, cyclosporine, or danazol. In the first case, we evaluated the appropriateness of timing for adjusting VEN dosage subsequent to the cessation of posaconazole. Consequently, modifying the VEN dosage in conjunction with the cessation of Posaconazole simultaneously may result in elevated plasma VEN levels. In the second case, plasma VEN concentrations were markedly elevated when co-administered with several CYP3A4 inhibitors. Additionally, in vitro assays were conducted for reverse translational studies to analyze CYP3A4 inhibition. CYP3A4 inhibition by combinatorial administration of cyclosporine A and danazol was demonstrated in vitro, which potentially explains the increasing plasma VEN concentrations observed in clinical settings. Although the acquisition of therapeutic effects is a major priority for patients, frequent therapeutic drug monitoring and dosage adjustments considering DDIs would be important factors in chemotherapy.

Association of the modified Glasgow prognostic score and prognostic nutritional index with duration of oral anamorelin administration in patients with cancer cachexia: a retrospective cohort study.

BACKGROUND: The modified Glasgow Prognostic Score (mGPS) and Prognostic Nutritional Index (PNI) are indicators of nutritional status in cancer patients; however, the effects of baseline mGPS and PNI on the duration of administration of the ghrelin receptor agonist anamorelin, which is used to treat cachexia in patients with cancer, are unclear. This study aimed to clarify the association of mGPS and PNI with the duration of oral anamorelin administration for patients who did not have beneficial effects from anamorelin. METHODS: The attending physician determined the duration of oral anamorelin administration based on discontinuation due to cancer progression, poor efficacy, adverse events, or death. RESULTS: The 12-week continuation rate of oral anamorelin was 30.4%. Univariate analysis revealed that an Eastern Cooperative Oncology Group performance status (ECOG-PS) of ≥2 (P < .001), concurrent chemotherapy (P = .002), albumin level (P = .005), C-reactive protein level (P = .013), and a mGPS of 2 (P = .014) were statistically significant predictors of the 12-week continuation rate of oral anamorelin. In the multivariate analysis, a mGPS of 2 remained a significant risk factor, and the ECOG-PS and concurrent chemotherapy had no effect on the association between the mGPS and 12-week continuation rate of oral anamorelin. CONCLUSION: Patients with a mGPS of 2, compared with mGPS of 0 or 1, are less likely to maintain oral anamorelin therapy, regardless of the ECOG-PS or concurrent chemotherapy. Therefore, it is necessary to consider initiating anamorelin administration at mGPS 0 or 1.

Eichner classification based on panoramic X-ray images using deep learning: A pilot study.

BACKGROUND: Research using panoramic X-ray images using deep learning has been progressing in recent years. There is a need to propose methods that can classify and predict from image information. OBJECTIVE: In this study, Eichner classification was performed on image processing based on panoramic X-ray images. The Eichner classification was based on the remaining teeth, with the aim of making partial dentures. This classification was based on the condition that the occlusal position was supported by the remaining teeth in the upper and lower jaws. METHODS: Classification models were constructed using two convolutional neural network methods: the sequential and VGG19 models. The accuracy was compared with the accuracy of Eichner classification using the sequential and VGG19 models. RESULTS: Both accuracies were greater than 81%, and they had sufficient functions for the Eichner classification. CONCLUSION: We were able to build a highly accurate prediction model using deep learning scratch sequential model and VGG19. This predictive model will become part of the basic considerations for future AI research in dentistry.

Development of a simultaneous LC-MS/MS analytical method for plasma: 16 antipsychotics approved in Japan and 4 drug metabolites.

The increased risk of adverse drug reactions due to the concomitant use of antipsychotics is problematic in the treatment of schizophrenia. Therefore, the simultaneous analysis of their plasma concentrations is required. In this study, we developed a simultaneous liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for analyzing plasma antipsychotics approved in Japan for therapeutic drug monitoring (TDM) applications. First, we counted the prescriptions for 16 antipsychotics and concomitant drugs used at the Tohoku University Hospital. LC-MS/MS was used for the simultaneous analysis of 16 antipsychotics and four drug metabolites. This analysis was conducted using a combination of selected reaction monitoring mode and reversed-phase chromatography. Following the examination of the MS/MS and LC conditions, an analytical method validation test was conducted. The developed method was used to analyze plasma antipsychotic levels in patients with schizophrenia. One-third of the patients received treatment with multiple antipsychotics. Under LC-MS/MS conditions, LC separation was performed using a combination of a C18 column and ammonium formate-based mobile phases with a gradient flow. The calibration curves were optimized by adjusting the ion abundance, and 11 compounds met the criteria for intra- and inter-day reproducibility tests. Some stability test results did not meet these criteria; therefore, further investigation is required. The developed method permitted the measurement of all the plasma parameters, including concentrations above the therapeutic range. Therefore, this method may be useful in the daily TDM practice of antipsychotics.

The Use of an Antioxidant Enables Accurate Evaluation of the Interaction of Curcumin on Organic Anion-Transporting Polypeptides 4C1 by Preventing Auto-Oxidation.

Flavonoids have garnered attention because of their beneficial bioactivities. However, some flavonoids reportedly interact with drugs via transporters and may induce adverse drug reactions. This study investigated the effects of food ingredients on organic anion-transporting polypeptide (OATP) 4C1, which handles uremic toxins and some drugs, to understand the safety profile of food ingredients in renal drug excretion. Twenty-eight food ingredients, including flavonoids, were screened. We used ascorbic acid (AA) to prevent curcumin oxidative degradation in our method. Twelve compounds, including apigenin, daidzein, fisetin, genistein, isorhamnetin, kaempferol, luteolin, morin, quercetin, curcumin, resveratrol, and ellagic acid, altered OATP4C1-mediated transport. Kaempferol and curcumin strongly inhibited OATP4C1, and the Ki values of kaempferol (AA(-)), curcumin (AA(-)), and curcumin (AA(+)) were 25.1, 52.2, and 23.5 µM, respectively. The kinetic analysis revealed that these compounds affected OATP4C1 transport in a competitive manner. Antioxidant supplementation was determined to benefit transporter interaction studies investigating the effects of curcumin because the concentration-dependent curve evidently shifted in the presence of AA. In this study, we elucidated the food-drug interaction via OATP4C1 and indicated the utility of antioxidant usage. Our findings will provide essential information regarding food-drug interactions for both clinical practice and the commercial development of supplements.

Mechanochemical synthesis of cerium chlorapatite from a mixture of cerium chloride heptahydrate, dicalcium phosphate dihydrate, and calcium hydroxide for biomedical application.

BACKGROUND: Cerium ions promote osteoclastogenesis and activate bone metabolism, while cerium oxide nanoparticles exhibit potent anti-inflammatory properties, making them promising for biomedical applications. OBJECTIVE: The purpose of this study was to develop and evaluate a synthesis method for sustained-release cerium-ion bioceramics containing apatite. Substituted apatite was found to be an effective biomaterial. METHODS: Cerium-containing chlorapatite was synthesized using a mechanochemical method employing dicalcium phosphate, cerium chloride heptahydrate, and calcium hydroxide as raw materials. The synthesized samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy. RESULTS: Cerium chlorapatite was successfully synthesized in the 10.1% and 20.1% samples. However, at Ce concentrations higher than 30.2%, the samples consisted of three or more phases, indicating the instability of a single phase. CONCLUSION: The method used in this study was found to be more efficient and cost-effective than the precipitation method for producing substituted apatite and calcium phosphate-based biomaterials. This research contributes to the development of sustained-release cerium-ion bioceramics with potential applications in the field of biomedicine.

Global Proteomics for Identifying the Alteration Pathway of Niemann-Pick Disease Type C Using Hepatic Cell Models.

Niemann-Pick disease type C (NPC) is an autosomal recessive disorder with progressive neurodegeneration. Although the causative genes were previously identified, NPC has unclear pathophysiological aspects, and patients with NPC present various symptoms and onset ages. However, various novel biomarkers and metabolic alterations have been investigated; at present, few comprehensive proteomic alterations have been reported in relation to NPC. In this study, we aimed to elucidate proteomic alterations in NPC and perform a global proteomics analysis for NPC model cells. First, we developed two NPC cell models by knocking out NPC1 using CRISPR/Cas9 (KO1 and KO2). Second, we performed a label-free (LF) global proteomics analysis. Using the LF approach, more than 300 proteins, defined as differentially expressed proteins (DEPs), changed in the KO1 and/or KO2 cells, while the two models shared 35 DEPs. As a bioinformatics analysis, the construction of a protein-protein interaction (PPI) network and an enrichment analysis showed that common characteristic pathways such as ferroptosis and mitophagy were identified in the two model cells. There are few reports of the involvement of NPC in ferroptosis, and this study presents ferroptosis as an altered pathway in NPC. On the other hand, many other pathways and DEPs were previously suggested to be associated with NPC, supporting the link between the proteome analyzed here and NPC. Therapeutic research based on these results is expected in the future.

High throughput LC/ESI-MS/MS method for simultaneous analysis of 20 oral molecular-targeted anticancer drugs and the active metabolite of sunitinib in human plasma.

Many types of oral molecular-targeted anticancer drugs are clinically used in cancer genomic medicine. Combinations of multiple molecular-targeted anticancer drugs are also being investigated, expecting to prolong the survival of patients with cancer. Therapeutic drug monitoring of oral molecular-targeted drugs is important to ensure efficacy and safety. A liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has been used for simultaneous determination of these drugs in human plasma. However, the sensitivity of mass spectrometers and differences in the therapeutic range of drugs have rendered the development of simultaneous LC/ESI-MS/MS methods difficult. In this study, a simultaneous quantitative method for 20 oral molecular-targeted anticancer drugs and the active metabolite of sunitinib was developed based on the results of linear range shifts of the calibration curves using four ion abundance adjustment techniques (collision energy defects, in-source collision-induced dissociation, secondary product ion selected reaction monitoring, and isotopologue selected reaction monitoring). The saturation of the detector for the seven analytes was resolved by incorporating optimal ion abundance adjustment techniques. Furthermore, the reproducibility of this method was confirmed in validation tests, and plasma from patients was measured by this method to demonstrate its usefulness in actual clinical practice. This analytical method is expected to make a substantial contribution to the promotion of personalized medicine in the future.

The prevalence of end-of-life chemotherapy and targeted therapy in Japan, assessed using a health claims database.

PURPOSE: This study aimed to investigate the current status of end-of-life chemotherapy and targeted therapy and explore the aggressiveness of end-of-life care in Japan using the DeSC database, a large administrative claims database. METHODS: We identified fatal cases of at least one cancer-related diagnosis between April 2015 and November 2020. Patients prescribed at least one anticancer drug were analyzed, and chemotherapy regimens were categorized based on the combination of concomitant anticancer drugs prescribed. RESULTS: Among 1,095,713 individuals enrolled in the National Health Insurance database, 7,300 deaths with cancer-related diagnosis were identified. Of these, 4,010 cases were identified in which at least one anticancer drug was prescribed, and 11.6% of 7,300 death had been prescribed anticancer drugs in their last 30 days of life. The most commonly used regimen was S-1 (tegafur, gimeracil, and oteracil potassium combination) monotherapy, followed by nivolumab monotherapy and nab-paclitaxel plus gemcitabine. Immune checkpoint inhibitor monotherapy was more likely prescribed to patients whose last chemotherapy dose was in the last 30 days of life (p = 0.0066, chi-squared test). CONCLUSIONS: This study provides insights into the current status of end-of-life chemotherapy and targeted therapy in Japan, using a large administrative claims database. The results of this study will inform future research on end-of-life chemotherapy and targeted therapy, and help develop strategies to improve the quality of life of patients with advanced cancer.

Therapeutic Drug Monitoring of Blood Sirolimus and Tacrolimus Concentrations for Polypharmacy Management in a Lymphangioleiomyomatosis Patient Taking Two Cytochrome P450 3A Inhibitors.

Patients with lymphangioleiomyomatosis (LAM) and lung transplantations are treated with multiple drugs, such as tacrolimus, mycophenolate mofetil, prednisolone, and itraconazole, for long-term suppression of rejection response and prevention of infection. Additional drugs are required when lung transplant recipients develop graft complications. Therefore, managing polypharmacy is critical because of drug-drug interactions caused by various factors, including drug-metabolizing enzymes such as cytochrome P450 3A (CYP3A). The patient was a 48-year-old woman (height 144.9 cm and weight 38.4 kg) who underwent lung transplantation for LAM. Mycophenolate mofetil, tacrolimus (target blood concentration, 4.0-8.0 ng/mL), and prednisolone were administered for immunosuppression, and itraconazole and clarithromycin were administered to manage graft infection. The patient developed unilateral lymphedema, predominantly in the left leg; therefore, sirolimus was initiated with a target blood concentration of 3.0-5.0 ng/mL. In addition to 1.0 mg/day of sirolimus, tacrolimus (0.3 mg/day), itraconazole (100 mg/day), and clarithromycin (800 mg/day) were added. Blood sirolimus concentrations ranged from 18.8 to 36.9 ng/mL on days 6 to 9; thus, treatment with sirolimus was stopped because of over-target blood concentrations. Blood concentrations of sirolimus and tacrolimus were successfully managed without adverse events using therapeutic drug monitoring (TDM) and azole anti-fungal substitution of azithromycin instead of clarithromycin although sirolimus concentration was relatively lower compared to the target range. Thereby, frequent TDM, management of polypharmacy that influences CYP3A activity, and possibly CYP3A genotyping should be appropriately conducted for personalized medicine.

Development of a Simultaneous Liquid Chromatography-Tandem Mass Spectrometry Analytical Method for Urinary Endogenous Substrates and Metabolites for Predicting Cytochrome P450 3A4 Activity.

CYP3A4, which contributes to the metabolism of more than 30% of clinically used drugs, exhibits high variation in its activity; therefore, predicting CYP3A4 activity before drug treatment is vital for determining the optimal dosage for each patient. We aimed to develop and validate an LC-tandem mass spectrometry (LC-MS/MS) method that simultaneously measures the levels of CYP3A4 activity-related predictive biomarkers (6ß-hydroxycortisol (6ß-OHC), cortisol (C), 1ß-hydroxydeoxycholic acid (1ß-OHDCA), and deoxycholic acid (DCA)). Chromatographic separation was achieved using a YMC-Triart C18 column and a gradient flow of the mobile phase comprising deionized water/25% ammonia solution (100 : 0.1, v/v) and methanol/acetonitrile/25% ammonia solution (50 : 50 : 0.1, v/v/v). Selective reaction monitoring in the negative-ion mode was used for MS/MS, and run times of 33 min were used. All analytes showed high linearity in the range of 3-3000 ng/mL. Additionally, their concentrations in urine samples derived from volunteers were analyzed via treatment with deconjugation enzymes, ignoring inter-individual differences in the variation of other enzymatic activities. Our method satisfied the analytical validation criteria under clinical conditions. Moreover, the concentrations of each analyte were quantified within the range of calibration curves for all urine samples. The conjugated forms of each analyte were hydrolyzed to accurately examine CYP3A4 activity. Non-invasive urine sampling employed herein is an effective alternative to invasive plasma sampling. The analytically validated simultaneous quantification method developed in this study can be used to predict CYP3A4 activity in precision medicine and investigate the potential clinical applications of CYP3A4 biomarkers (6ß-OHC/C and 1ß-OHDCA/DCA ratios).

Development of a Highly Sensitive and Rapid Liquid Chromatography-Tandem Mass Spectrometric Method Using a Basic Mobile Phase Additive to Determine the Characteristics of the Urinary Metabolites for Niemann-Pick Disease Type C.

As Niemann-Pick disease type C (NPC) is difficult to diagnose owing to its various clinical symptoms; biomarker tests have been developed. Previously, we revealed urinary sulfated cholesterol metabolites as noninvasive biomarkers for NPC. However, LC/tandem mass spectrometry (LC/MS/MS) requires long separation time and large urine volumes. Recently, a basic mobile phase was reported to increase the MS intensity. Thus, we developed a highly sensitive and rapid LC/MS/MS method for analyzing urinary cholesterol metabolites using a basic mobile phase additive. 3ß-Sulfooxy-7ß-N-acetylglucosaminyl-5-cholenic acid, its glycine and taurine conjugates, 3ß-sulfooxy-7ß-hydroxy-5-cholenic acid, and 7-oxo form were measured, with selected reaction monitoring in negative ion mode. Oasis HLB and L-column 3 were used for column-switching LC/MS/MS and urine diluted 10-fold was employed as the sample. After trapping, gradient separation was performed using solutions containing 1% (v/v) ammonium solution. On average, a 16-fold increase in peak areas was observed compared to that obtained at pH 5.5 with the mobile phases. Although the previous method needed 60 min for separation from interference peaks, we succeeded to separate them in 7 min with optimized LC condition. Further, all compounds showed good linearity from 0.3-1000 ng/mL, with satisfactory intra- and inter-day reproducibility. The developed method was applied to the urinalysis of healthy participants and NPC patients. Overall, the concentrations of metabolites correlated with those obtained using the previous method. Therefore, we succeeded to increasing MS intensity and shorten LC running time; and the method is useful for the noninvasive diagnostic screening of patients with NPC.

Bile Acid-Drug Interaction via Organic Anion-Transporting Polypeptide 4C1 Is a Potential Mechanism of Altered Pharmacokinetics of Renally Excreted Drugs.

Patients with liver diseases not only experience the adverse effects of liver-metabolized drugs, but also the unexpected adverse effects of renally excreted drugs. Bile acids alter the expression of renal drug transporters, however, the direct effects of bile acids on drug transport remain unknown. Renal drug transporter organic anion-transporting polypeptide 4C1 (OATP4C1) was reported to be inhibited by chenodeoxycholic acid. Therefore, we predicted that the inhibition of OATP4C1-mediated transport by bile acids might be a potential mechanism for the altered pharmacokinetics of renally excreted drugs. We screened 45 types of bile acids and calculated the IC50, Ki values, and bile acid−drug interaction (BDI) indices of bile acids whose inhibitory effect on OATP4C1 was >50%. From the screening results, lithocholic acid (LCA), glycine-conjugated lithocholic acid (GLCA), and taurine-conjugated lithocholic acid (TLCA) were newly identified as inhibitors of OATP4C1. Since the BDI index of LCA was 0.278, LCA is likely to inhibit OATP4C1-mediated transport in clinical settings. Our findings suggest that dose adjustment of renally excreted drugs may be required in patients with renal failure as well as in patients with hepatic failure. We believe that our findings provide essential information for drug development and safe drug treatment in clinics.

Evaluation of a Capillary Microsampling Device for Analyzing Plasma Lenvatinib Concentration in Patients With Hepatocellular Carcinoma.

BACKGROUND: The anticancer drug, Lenvima (lenvatinib), has severe side effects. Therapeutic drug monitoring helps ensure its efficacy and safety. Regular and optimally timed blood sampling is tough, especially when lenvatinib is self-medicated. Microsampling using the easy to handle Microsampling Wing (MSW) may help circumvent this problem. However, current lenvatinib detection methods are not sensitive enough to detect its concentrations in microsamples (<50-250 µL). Thus, the aim of this study was 2-fold (1) develop an analytic method to estimate plasma lenvatinib concentrations in microsamples and (2) verify whether this method works on micro (5.6 µL) blood plasma samples obtained clinically through MSW from patients with unresectable hepatocellular carcinoma (HCC). METHODS: A simple, highly sensitive, and specific liquid chromatography-electrospray ionization tandem mass spectrometry method was developed. Using this novel protocol, the trough blood plasma concentration of lenvatinib was measured for both blood sampled conventionally and that using MSW. Thirty-five venous whole blood samples were obtained from 11 patients with HCC. Furthermore, the stability of lenvatinib in MSW samples during storage was evaluated. RESULTS: The mean plasma lenvatinib concentration estimates were not significantly different between the MSW and conventional venous blood samples. CV for interday and intraday assays was low. Up to day 5, the lenvatinib concentration in the MSW samples was 85%-115% of the initial day concentration (when stored at 25°C or 4°C). The interference of endogenous matrix components in the human plasma was low. CONCLUSIONS: These results indicate that the novel mass spectrometry protocol accurately measures lenvatinib in human plasma and is reproducible. Thus, MSW could be a useful microsampling device for lenvatinib therapeutic drug monitoring in patients with HCC when used in combination with this novel liquid chromatography-electrospray ionization tandem mass spectrometry detection method.

Metabolic Alteration Analysis of Steroid Hormones in Niemann-Pick Disease Type C Model Cell Using Liquid Chromatography/Tandem Mass Spectrometry.

Niemann-Pick disease type C (NPC) is an autosomal recessive disease caused by a functional deficiency of cholesterol-transporting proteins in lysosomes, and exhibits various clinical symptoms. Since mitochondrial dysfunction in NPC has recently been reported, cholesterol catabolism to steroid hormones may consequently be impaired. In this study, we developed a comprehensive steroid hormone analysis method using liquid chromatography/tandem mass spectrometry (LC-MS/MS) and applied it to analyze changes in steroid hormone concentrations in NPC model cells. We investigated the analytical conditions for simultaneous LC-MS/MS analysis, which could be readily separated from each other and showed good reproducibility. The NPC phenotype was verified as an NPC model with mitochondrial abnormalities using filipin staining and organelle morphology observations. Steroid hormones in the cell suspension and cell culture medium were also analyzed. Steroid hormone analysis indicated that the levels of six steroid hormones were significantly decreased in the NPC model cell and culture medium compared to those in the wild-type cell and culture medium. These results indicate that some steroid hormones change during NPC pathophysiology and this change is accompanied by mitochondrial abnormalities.