Preferential meropenem absorption activated by 1α,25-dihydroxyvitamin D3 and shared with foscarnet, a phosphate transporter substrate, in the rat ileum.

Meropenem (MEPM) is used for the treatment of serious infectious diseases solely as. INJECTABLE: Therefore, the development of an oral formulation would expand its clinical utility. To this end, an exact understanding of the absorption characteristics of MEPM is essential. In this study, MEPM absorption in the rat small intestine was investigated using an in situ loop technique and an in vitro diffusion chamber method. The disappearance ratios of MEPM (0.1 mM) were in the order of ileum > duodenum > jejunum. The extensive MEPM disappearance in the ileum was significantly reduced in the presence of foscarnet, a Na+-dependent phosphate transporter (NaPi-T) substrate, whereas glycylsarcosine, thiamine, taurocholic acid, and biapenem had no effects. The mucosal-to-serosal (M-to-S) permeation of MEPM across the rat ileal segments was very small under normal experimental conditions. However, on addition of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) to the experimental medium, the M-to-S permeation of MEPM markedly increased, showing a more than 7-fold greater apparent permeation coefficient. The present results suggest that MEPM is preferentially absorbed in the rat ileum, sharing with foscarnet, and that 1,25(OH)2D3 potentially activates the absorption of MEPM there. A likely candidate for involvement in MEPM absorption was NaPi-T or a related transporter.

Synthesis of (22R)-, (22S)-22-Fluoro-, and 22,22-Difluoro-25-hydroxyvitamin D3 and Effects of Side-Chain Fluorination on Biological Activity and CYP24A1-Dependent Metabolism.

Three novel analogues of C22-fluoro-25-hydroxyvitamin D3 (5-7) were synthesized and evaluated to investigate the effects of side-chain fluorination on biological activity and metabolism of vitamin D. These novel analogues were constructed by convergent synthesis applying the Wittig-Horner coupling reaction between CD-ring ketones (41,42,44) and A-ring phosphine oxide (11). The introduction of C22-fluoro units was achieved by stereoselective deoxy-fluorination for synthesizing 5 and 6 or two-step cationic fluorination for 7. The absolute configuration of the C22-fluoro-8-oxo-CD-ring (39) was confirmed by X-ray crystallographic structure determination. The basic biological activity of the side-chain fluorinated analogues, including compounds (5-7), was evaluated. Generally, osteocalcin promoter transactivation activity decreased in the order of C24-fluoro, C23-fluoro, and C22-fluoro analogues. In addition, the metabolic stability of C22-fluoro-25-hydroxyvitamin D3 (5-7) against hCYP24A1 metabolism was also evaluated. 22,22-Difluoro-25(OH)D3 (7) was more stable against hCYP24A1 metabolism compared with its non-fluorinated counterpart 25-hydroxyvitamin D3 (1), but fluorination at the C22 position had little effect on the metabolic stability compared with C24- and C23-fluoro analogues. Our research clarified that side-chain fluorination in vitamin D markedly changes CYP24A1 metabolic stability depending on the fluorinating position.

Synthesis of New 26,27-Difluoro- and 26,26,27,27-Tetrafluoro-25-hydroxyvitamin D3: Effects of Terminal Fluorine Atoms on Biological Activity and Half-life.

As an extension of our research on providing a chemical library of side-chain fluorinated vitamin D3 analogues, we newly designed and synthesized 26,27-difluoro-25-hydroxyvitamin D3 (1) and 26,26,27,27-tetrafluoro-25-hydroxyvitamin D3 (2) using a convergent method applying the Wittig-Horner coupling reaction between CD-ring ketones (13, 14) and A-ring phosphine oxide (5). The basic biological activities of analogues, 1, 2, and 26,26,26,27,27,27-hexafluoro-25-hydroxyvitamin D3 [HF-25(OH)D3] were examined. Although the tetrafluorinated new compound 2 exhibited higher binding affinity for vitamin D receptor (VDR) and resistance to CYP24A1-dependent metabolism compared with the difluorinated 1 and its non-fluorinated counterpart 25-hydroxyvitamin D3 [25(OH)D3], HF-25(OH)D3 showed the highest activity among these compounds. Osteocalcin promoter transactivation activity of these fluorinated analogues was tested, and it decreased in the order of HF-25(OH)D3, 2, 1, and 25(OH)D3 in which HF-25(OH)D3 showed 19-times greater activity than the natural 25(OH)D3.

Development of a magnetic nanoparticle-based method for concentrating SARS-CoV-2 in wastewater.

Several virus concentration methods have been developed to increase the detection sensitivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater, as part of applying wastewater-based epidemiology. Polyethylene glycol (PEG) precipitation method, a method widely used for concentrating viruses in wastewater, has some limitations, such as long processing time. In this study, Pegcision, a PEG-based method using magnetic nanoparticles (MNPs), was applied to detect SARS-CoV-2 in wastewater, with several modifications to increase its sensitivity and throughput. An enveloped virus surrogate, Pseudomonas phage φ6, and a non-enveloped virus surrogate, coliphage MS2, were seeded into wastewater samples and quantified using reverse transcription-quantitative polymerase chain reaction to assess the recovery performance of the Pegcision. Neither increasing MNP concentration nor reducing the reaction time to 10 min affected the recovery, while adding polyacrylic acid as a polyanion improved the detection sensitivity. The performance of the Pegcision was further compared to that of the PEG precipitation method based on the detection of SARS-CoV-2 and surrogate viruses, including indigenous pepper mild mottle virus (PMMoV), in wastewater samples (n = 27). The Pegcision showed recovery of 14.1 ± 6.3 % and 1.4 ± 1.0 % for φ6 and MS2, respectively, while the PEG precipitation method showed recovery of 20.4 ± 20.2 % and 18.4 ± 21.9 % (n = 27 each). Additionally, comparable PMMoV concentrations were observed between the Pegcision (7.9 ± 0.3 log copies/L) and PEG precipitation methods (8.0 ± 0.2 log copies/L) (P > 0.05) (n = 27). SARS-CoV-2 RNA was successfully detected in 11 (41 %) each of 27 wastewater samples using the Pegcision and PEG precipitation methods. The Pegcision showed comparable performance with the PEG precipitation method for SARS-CoV-2 RNA concentration, suggesting its applicability as a virus concentration method.

Inhibitory effects of indoxyl sulfate and creatinine on the renal transport of meropenem and biapenem in rats.

Carbapenem antibiotics are excreted preferentially in the urine after intravenous administration, with organic anion transporters (OATs) known to be involved in the renal tubular secretion of carbapenem antibiotics. Various uremic toxins (UTs) accumulate in the blood of patients with end-stage renal failure, and some UTs such as indoxyl sulfate (IS) and creatinine (Cr) are excreted in the urine via OATs. However, information about the possible interactions between these UTs and carbapenems in the renal secretion remains limited. In this study, we investigated the effects of IS and Cr on the renal transport of anionic meropenem and zwitterionic biapenem by using rat renal cortical slices. The uptake of meropenem and biapenem in the renal cortical slices was significantly decreased in the presence of 0.1 mM IS or 1 mM Cr. When biapenem and Cr were co-administered to rats intravenously, biapenem clearance from the plasma was clearly retarded, reflecting the current in vitro results. However, IS and Cr exerted no inhibitory effect on the uptake of metformin, a substrate of renal organic cation transporter (OCT) 2, in the renal cortical slices. Thus, our findings indicate that IS and Cr interfere with the renal secretion of carbapenem antibiotics by preferentially inhibiting OATs.

Downregulated expression of organic anion transporting polypeptide (Oatp) 2b1 in the small intestine of rats with acute kidney injury.

The expression of transporters on the apical and basal membranes of renal tubular cells is modulated under acute kidney injury (AKI). However, little is known about alterations in non-renal transporters in the tissues other than the kidney under AKI situation. This study aimed to assess the modulation of organic anion transporting polypeptide (Oatp) 1a2 and Oatp2b1 expression/function in the small intestine of rats with drug-induced AKI. AKI was induced by intraperitoneal administration of cisplatin at a dose of 5 mg/kg. On day 3 after cisplatin administration, morphological changes in the small intestine, Oatp1a2 and Oatp2b1 expression, and absorption of pravastatin and theophylline were evaluated. Non-negligible atrophy was observed in the jejunum and ileum of the AKI rats. However, the absorption of theophylline was not affected. While intestinal Oatp2b1 expression was markedly decreased in the AKI rats, no alteration was observed in Oatp1a2 expression. The plasma levels of pravastatin after intraluminal administration declined significantly in the AKI rats. However, no such decline was observed after intravenous administration. This study suggested that the responses of intestinal Oatps to experimentally induced AKI was not unidirectional and that pravastatin absorption was governed more potently by Oatp2b1 than by Oatp1a2 in the rat intestine.

Downregulated expression of intestinal P-glycoprotein in rats with cisplatin-induced acute kidney injury causes amplification of its transport capacity to maintain "gatekeeper" function.

The expression of transporters on the apical and basal membranes of renal proximal tubular cells are down- or upregulated to various extents under cisplatin (CDDP)-induced acute kidney injury (AKI). However, little is known about the changes in transporters in tissues other than the kidney under CDDP-induced AKI. This study aimed to investigate the modulation of the expression/function of intestinal efflux transporters, P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp), in CDDP-induced AKI rats. On day 3 after the intraperitoneal administration of CDDP (5 mg/kg) to rats, the expression levels of P-gp and Bcrp were compared with those of normal rats. Further, the absorption of three P-gp substrates (6α-methylprednisolone, rhodamine 123, and gatifloxacin) was evaluated in both groups using conventional loop techniques. In the CDDP-induced AKI rats, P-gp expression in the ileum was markedly decreased to approximately 38% of that in the normal rats. However, no significant changes in Bcrp expression were observed in the AKI rats. In contrast with the reduction in P-gp expression in the AKI rats, the absorption of the three P-gp substrates remained almost the same or decreased in the AKI group. The addition of verapamil (a potent P-gp inhibitor) increased the absorption of the three P-gp substrates to the values obtained from the normal rats. In conclusion, our results suggested that P-gp expression is downregulated in rats with CDDP-induced AKI but that P-gp maintains its potency as a "gatekeeper" against the absorption of xenobiotics by amplifying its individual transport capacity under these conditions.

[Investigation of Leftover Hyperphosphatemia Drugs in Hemodialysis Outpatients].

Currently, various hyperphosphatemia drugs are administered orally to hemodialysis patients in order to lower serum phosphorus levels. However, it is known that medication adherence is poor, possibly due to greater pill burden taken each time and their complicated schedules. Therefore, large amounts of unused hyperphosphatemia drugs are likely to be leftover. The increase in leftover prescribed drugs leads to the unnecessary elevation of medical care costs. To date, however, the available information on leftover hyperphosphatemia drugs in hemodialysis outpatients is limited. In this study, we performed an interview survey of medication adherence to hyperphosphatemia drugs among 60 hemodialysis outpatients and evaluated the cost of the leftover drugs. Thirty-four patients showed good adherence. On the other hand, 19 patients self-adjusted to take hyperphosphatemia drugs according to their daily diet. When assessing the serum phosphorus levels for these patients over the past year, the values often exceeded the targeted range (3.5-6.0 mg/mL). Furthermore, 35 patients kept hyperphosphatemia drugs at their home. When estimating the cost derived from leftover drugs using the bootstrap method, main distribution of drug cost was shown to be in the range of 2000 to 2500 yen. This drug cost seemed to in part reflect preparation for an emergency. A serious problem was that 14 patients had previous experience in discarding hyperphosphatemia drugs. This study suggested that more appropriate pharmaceutical care according to each patient's situation is essential in improving phosphorus control in hemodialysis outpatients and in reducing the waste of medical resources.

Influence of Constant Torque Stretching at Different Stretching Intensities on Flexibility and Mechanical Properties of Plantar Flexors.

ABSTRACT: Oba, K, Samukawa, M, Nakamura, K, Mikami, K, Suzumori, Y, Ishida, Y, Keeler, N, Saitoh, H, Yamanaka, M, and Tohyama, H. Influence of constant torque stretching at different stretching intensities on flexibility and mechanical properties of plantar flexors. J Strength Cond Res 35(3): 709-714, 2021-The purpose of this study was to examine the effects of constant torque stretching (CTS) at different stretching intensities on the maximal range of motion (ROM) and muscle-tendon unit (MTU) stiffness of plantar flexors. Fourteen healthy men performed 4 trials of differing stretch intensities: no stretching (control), 50, 75, and 100%. Stretch intensity was defined as maximum passive resistive torque predetermined at a familiarization trial. Each stretch trial consisted of 5 sets of 60-second CTS at the designated stretch intensity. Both maximal ROM and passive resistive torque were assessed during passive dorsiflexion, and MTU stiffness was calculated using the torque-angle curves measured before and after CTS. There were no significant differences in maximal ROM or MTU stiffness at the baseline condition. After the intervention, significantly greater maximal ROM and significantly lower MTU stiffness were observed in the 100% CTS condition than the control condition, whereas there were no significant differences between the submaximal intensity condition (i.e., 50 or 75% intensity) and the control condition. Therefore, our findings suggest that maximal intensity stretching is the most effective approach for improving both flexibility and MTU stiffness with CTS.

[Factors Resulting Correlation and Differences in Renal Function Evaluation Index Using the Serum Cystatin C and Creatinine as Measured by an Enzymatic Method].

We previously reported the association of the estimated glomerular filtration rate (eGFRcreat) calculated from the serum creatinine level (S-Cr) measured using the Jaffe method with the GFR (eGFRcys) estimated from the serum cystatin C level (CysC). However, few studies have compared the eGFRcreat using the enzymatic method with the eGFRcys. It is unclear whether there are differences in the results of renal function assessment. The purpose of this study was to compare the eGFRcreat calculated from the S-Cr with the eGFRcys calculated from the CysC in patients in whom the S-Cr and CysC were simultaneously measured using the enzymatic method, examine the correlations of respective parameters, and clarify physiological factors involved in differences among the parameters. The subjects were 1334 patients treated in 5 institutions. The mean values and correlation coefficient were statistically analyzed using Student's t-test and Pearson's test, respectively. Influential factors between formulae were analyzed using multiple regression analysis. The mean eGFRcreat was 67.0 mL/min/1.73 m2, being significantly higher than the mean eGFRcys (63.2). Multiple regression analysis showed that factors influencing differences in the S-Cr and CysC included the sex, age, serum albumin, and blood urea nitrogen BUN/S-Cr. Furthermore, factors involved in the overestimation of the eGFRcreat in comparison with the eGFRcys included the serum albumin and BUN/S-Cr. The differences between the eGFRcreat calculated from the S-Cr and eGFRcys were less marked than when adopting the Jaffe method in our previous study. However, the eGFRcreat were higher than the eGFRcys in patients with malnutrition or dehydration.

Oncogenic Ras mutant causes the hyperactivation of NF-κB via acceleration of its transcriptional activation.

It is well established that nuclear factor κB (NF-κB) acts as one of the most important transcription factors for tumor initiation and progression, as it both protects cells from apoptotic/necrotic signals and accelerates angiogenesis and tumor metastasis, which is mediated via the expression of target genes. However, it has not yet been clarified how oncogenic signals accelerate the activation of NF-κB. In the current study, we utilized untransformed NIH-3T3 cells stably harboring a κB-driven luciferase gene to show that an oncogenic mutant of Ras GTPase augmented TNFα-induced NF-κB activation. Notably, enforced expression of cyclin-dependent kinase inhibitors, such as p27Kip1 and p21Cip1 , effectively canceled the accelerated activation of NF-κB, suggesting that oncogenic Ras-induced cell cycle progression is essential for the hyperactivation of NF-κB. Furthermore, we found that Ras (G12V) augmented the transcriptional activation of NF-κB, and this activation required the p38 MAP kinase. We observed that a downstream kinase of p38 MAP kinase, MSK1, was activated by Ras (G12V) and catalyzed the phosphorylation of p65/RelA at Ser-276, which is critical for its transcriptional activation. Significantly, phosphorylation of the p65/RelA subunit at Ser-276 was elevated in patient samples of colorectal cancer harboring oncogenic mutations of the K-Ras gene, and the expression levels of NF-κB target genes were drastically enhanced in several cancer tissues. These observations strongly suggest that oncogenic signal-induced acceleration of NF-κB activation is caused by activation of the p38 MAP kinase-MSK1 signaling axis and by cell cycle progression in cancer cells.

Forefoot and hindfoot kinematics in subjects with medial tibial stress syndrome during walking and running.

Excessive foot pronation during static standing, walking and running has been reported as a contributing factor for the development of medial tibial stress syndrome (MTSS). The motion of foot pronation consists of hindfoot and forefoot motion. However, no previous studies have investigated forefoot and hindfoot kinematics during walking and running in subjects with MTSS. The current study sought to compare hindfoot and forefoot kinematics between subjects with and without MTSS while walking and running. Eleven subjects with MTSS and 11 healthy controls (each group containing 10 males and one female) participated in the current study. Segment angles of the hindfoot and forefoot during walking and running barefoot on a treadmill were recorded using three-dimensional kinematic analysis. An independent t-test was used to compare kinematic data between groups. Subjects with MTSS exhibited significantly greater hindfoot eversion and abduction (p < 0.05) during walking and running than subjects without MTSS, significantly greater forefoot eversion and abduction (p < 0.05) during walking, and significantly greater forefoot abduction during running (p < 0.05). Hindfoot and forefoot kinematics during walking and running were significantly different between subjects with and without MTSS. For prevention and rehabilitation of MTSS, it may be important to focus on not only hindfoot but also forefoot kinematics during both running and walking. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Vitamin D derivatives inhibit hepatitis C virus production through the suppression of apolipoprotein.

Supplementation with vitamin D (VD) has been reported to improve the efficacy of interferon-based therapy for chronic hepatitis C. We found that 25-hydroxyvitamin D3 (25-(OH)D3), one of the metabolites of VD, has antiviral effects by inhibiting the infectious virus production of the hepatitis C virus (HCV). In this study, to clarify the underlying mechanisms of the anti-HCV effects, we searched VD derivatives that have anti-HCV effects and identified the common target molecule in the HCV life cycle by using an HCV cell culture system. After infection of Huh-7.5.1 cells with cell culture-generated HCV, VD derivatives were added to culture media, and the propagation of HCV was assessed by measuring the HCV core antigen levels in culture media and cell lysates. To determine the step in the HCV life cycle affected by these compounds, the single-cycle virus production assay was used with a CD81-negative cell line. Of the 14 structural derivatives of VD, an anti-HCV effect was detected in 9 compounds. Cell viability was not affected by these effective compounds. The 2 representative VD derivatives inhibited the infectious virus production in the single-cycle virus production assay. Treatment with these compounds and 25-(OH)D3 suppressed the expression of apolipoprotein A1 and C3, which are known to be involved in infectious virus production of HCV, and the knockdown of these apolipoproteins reduced infectious virus production. In conclusion, we identified several compounds with anti-HCV activity by screening VD derivatives. These compounds reduce the infectious virus production of HCV by suppressing the expression of apolipoproteins in host cells.

[The Usefulness of a Pamphlet for Preventing Exposure to Antineoplastic Agents at Cancer Patients' Homes and an Awareness Survey for Pharmacists about Providing Information to Cancer Patients about Exposure to Antineoplastic Agents].

As the number of patients undergoing outpatient chemotherapy has increased, there is concern that cancer patients' family members are unknowingly exposed to antineoplastic agents at home through cancer patients' excrement or other secreted materials. In this study, we created a pamphlet that introduces several methods to prevent exposure to antineoplastic agents at home and conducted a questionnaire survey to assess the usefulness of the pamphlet. The results indicated that more than 90% of patients believed that the pamphlet was "useful" or "very useful" for ensuring safety with respect to antineoplastic agents at home. Further, most patients responded that the pamphlet decreased their anxieties about their disease and/or treatment. In order to examine pharmacists' involvement in providing information to cancer patients about exposure to antineoplastic agents, we conducted another questionnaire survey, with pharmacists working at Sapporo-Higashi Tokushukai Hospital and Sapporo Tokushukai Hospital. The results indicated that 41 out of 46 pharmacists practiced medication counseling; however, 39 pharmacists did not provide patients with instructions on ways to prevent exposure to antineoplastic agents at home. Their primary reason was a lack of adequate information to do so. Accordingly, the pamphlet prepared in our study would be an effective way to provide guidance for preventing exposure to antineoplastic agents at home.

Strategies and limitations associated with in vitro characterization of vitamin D receptor activators.

In vitro cell-based assays are common screening tools used for the identification of new VDR ligands. For 25-hydroxyvitamin D3 [25(OH)D3] and 1α-hydroxyvitamin D3 [1α(OH)D3], protein expressions of CYP2R1 and CYP27B1, respectively, that form the active 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] ligand were detected in human embryonic kidney (HEK293) cells expressing the GAL4-hVDR, the human brain microvessel endothelial (hCMEC/D3) and adenocarcinoma colonic (Caco-2) cells. The impact of bioactivation enzymes was shown upon the addition of ketoconazole (10 µM KTZ), a pan-CYP inhibitor, which reduced the apparent potency of 25(OH)D3 and increased the EC50 from 272 to 608 nM in HEK293 cells. EIA assays verified that 1,25(OH)2D3 was formed and contributed to VDR activity independently of its precursors. In hCMEC/D3 cells where enzyme protein levels were lowest, changes in MDR1/P-gp expression with KTZ were minimal. In Caco-2 cells, the induction of TRPV6 (calcium channel), CYP24A1, CYP3A4, OATP1A2 and MDR1 mRNA expression was 1,25(OH)2D3 > 1α(OH)D3 > 25(OH)D3, with the magnitude of change being blunted by KTZ. Upon inclusion of KTZ in the cell-based assays, high transcriptional activities were observed for synthetic VDR activators from Teijin Pharma. Cyclopentanone derivatives: TPD-003, TPD-005, TPD-006, TPD-008 and TPD-009 (EC50s 0.06 to 67 nM, unchanged with KTZ) were found more potent over straight chain and lactone derivatives (antagonists). Most TPD compounds activated OATP1A2, CYP24A1, CYP3A4, and MDR1 (28-67%) and TRPV6 transcriptionally in Caco-2 cells. The results identified that cell-based assays with added KTZ could accurately identify new VDR activators, although these may be hypercalcemic with strong TRPV6 inducing properties.

Investigation on the Interactions between Various Drugs and Aojiru (Green Juice) Using a Simple Centrifugation Method.

The objective of this study was to evaluate the interactions between various drugs and aojiru (green juice), a popular health food in Japan, using a simple centrifugation method. The mixture of drug solution and aojiru suspension was gently shaken and centrifuged. The drug concentration in the supernatant fluid was then determined by HPLC. The concentration of rhodamine 123 (Rho-123), a model compound, in the supernatant fluid significantly decreased after mixing with aojiru, indicating extensive binding of Rho-123 to the insoluble components of aojiru. When administered into rat small intestinal loops together with aojiru, the plasma Rho-123 concentrations became much smaller than those when administered alone. This result strongly suggested that a strong interaction observed in vitro was well reflected in modulated absorption. Among seven drugs tested, chlorpromazine and imipramine exerted binding properties to aojiru similar to or greater than Rho-123. As a small part of both Rho-123 and imipramine was released when the aojiru precipitate was resuspended, their binding to aojiru was considered to be tight. The binding of diltiazem, fexofenadine, glibenclamide, metformin, and norfloxacin to aojiru was much weaker or almost negligible compared with that of chlorpromazine and imipramine. The present results suggest that aojiru can decrease the intestinal absorption of some clinically relevant drugs through tight binding in the small intestine and that the present centrifugation method is useful for predicting in vivo interactions between drugs and aojiru.

Correlations between Plasma Levels of Anionic Uremic Toxins and Clinical Parameters in Hemodialysis Patients.

When the kidney is seriously impaired, various uremic toxins (UTs) accumulate in the body, often exerting unfavorable effects on physiological functions and drug pharmacokinetics. To prevent this, it is important to determine plasma UT levels accurately in chronic kidney disease patients. Although attempts to predict plasma UT levels using biomarkers have been made, the correlation between UT levels and the markers is not yet fully understood. In this study, we assessed the correlations among plasma levels of indoxyl sulfate (IS), indoleacetic acid (IA), and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF) in 20 hemodialysis patients and evaluated the relationship between the plasma levels of UTs and clinical parameters, such as serum creatinine (Scr), blood urea nitrogen, and estimated glomerular filtration rate (eGFR), with special focus on IS. There were no correlations among the plasma levels of the three UTs before and immediately after hemodialysis. However, a significant correlation was observed between plasma IS levels and Scr before hemodialysis (r=0.643, p=0.002), with the correlation becoming much stronger when using the data obtained immediately after hemodialysis (r=0.744, p<0.001). Further, plasma IS levels showed a significant negative correlation with eGFR (r=-0.558, p=0.011). However, no correlations were observed for IA or CMPF. The results obtained from this study suggest that plasma IS levels can be predicted from Scr values, although the precise mechanism behind the correlation remains to be clarified.

Vitamin D Analogs with Nitrogen Atom at C2 Substitution and Effect on Bone Formation.

The Arg274 residue of the ligand binding domain of human vitamin D receptor (hVDR) is important for 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) binding as a specific ligand through forming a hydrogen bond with the 1α-OH group of the active vitamin D3, 1α,25(OH)2D3. An additional pincer-type hydrogen bond formation with Arg274 from a 2α-substituent of a synthetic 1α,25(OH)2D3 analog would enhance the binding affinity and biological activity. A series of 2α-[2-(heteroaryl)ethyl]-, 2α-(4-cyanobutyl)-, 2α-(ω-cyanoalkoxy)-, and 2ß-(3-cyanopropoxy)-1α,25(OH)2D3 were designed and synthesized based on our original hVDR super agonists of 2α-(3-hydroxypropyl)- and 2α-(3-hydroxypropoxy)-1α,25(OH)2D3. Their potential biological activities, i.e., hVDR binding affinity, transactivation activity in HOS cells, and therapeutic effect on enhancing the bone mineral density of OVX rats, were studied.

[Plasma concentrations of anionic uremic toxins in hemodialysis patients and their effects on protein binding of pravastatin].

Uremic toxins (UTs) accumulate in the body of hemodialysis patients. UTs often exert unfavorable effects on patients and cause significant interactions with clinically relevant drugs. In this study, we assayed plasma concentrations of three typical anionic UTs, indoxyl sulfate (IS), 3-indoleacetic acid (IA), and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF), in 20 hemodialysis patients and 5 healthy volunteers. Moreover, the effects of these anionic UTs on the binding of pravastatin to human serum albumin (HSA) were also evaluated. CMPF concentrations in the plasma of patients were unchanged before and after dialysis (63.0 ± 6.3 µM and 65.1 ± 6.7 µM, respectively), and these values were about 5-fold greater compared with those in healthy volunteers. Although dialysis decreased the plasma IS concentration from 157.9 ± 19.9 µM to 103.8 ± 13.3 µM, the value after hemodialysis was still ca. 27-fold greater than that in healthy volunteers. IA concentrations before and after hemodialysis were almost identical to those in healthy volunteers. There were no significant differences in the plasma concentrations of the three anionic UTs between male and female patients. The magnitude of protein binding was in the order CMPF>IS>IA, indicating that hemodialysis clearance of these anionic UTs was dependent on their protein binding capacities. The ability of IS to reduce pravastatin binding to HSA was much greater than that of CMPF. The present results suggest that statins bind to site II on HSA, and that their binding is modulated by IS when elevated in hemodialysis patients.