Pentafluorosulfanyl-substituted biaryl derivatives as MATE-type transporter inhibitors targeting drug-resistant bacteria.

Multidrug and toxin extrusion (MATE) inhibitors improve the antimicrobial susceptibility of drug-resistant bacteria by preventing the efflux of administered antibiotics. In this study, we optimized the chemical structure of a previously identified bacterial-selective MATE inhibitor 1 (EC50 > 30 µM) to improve its activity further. Compound 1 was divided into three fragments (aromatic part, linker part, and guanidine part), and each part was individually optimized. Compound 31 (EC50 = 1.8 µM), a novel pentafluorosulfanyl-containing molecule synthesized following optimized parts, showed antimicrobial activity against MATE-expressing strains at concentrations lower than conventional inhibitor 1 when co-administrated with norfloxacin. Furthermore, 31 was not cytotoxic at effective concentrations. This suggests that compound 31 can be a promising candidate for combating bacterial infections, particularly those resistant to conventional antibiotics by MATE expression.

Fluorophenylalkyl-substituted cyanoguanidine derivatives as bacteria-selective MATE transporter inhibitors for the treatment of antibiotic-resistant infections.

Drug efflux pump inhibitors for the multidrug resistance protein HmrM, a member of the multidrug and toxin extrusion (MATE) family of transporters, were investigated to increase the drug susceptibility of multidrug-resistant bacteria and restore the antimicrobial effect of fluoroquinolones, such as norfloxacin. The lead inhibitor, prepared from the known hMATE1 inhibitor cimetidine, reduced the norfloxacin resistance of HmrM-expressing strains by 92% at non-cytotoxic concentrations in human cells, and multidrug resistance protein MdtK-expressing strains by 86%. These results indicated that the inhibitor is a lead candidate for the development of drugs with a novel mechanism of action against infections caused by multidrug-resistant bacteria that act synergistically with antimicrobial drugs.

Differences in occupational stress by smoking intensity and gender in cross-sectional study of 59 355 Japanese employees using the Brief Job Stress Questionnaire (BJSQ): the Niigata Wellness Study.

OBJECTIVES: It has been hypothesised that smoking intensity may be related to occupational stress. This study aimed to investigate whether stress, including problems with superiors or co-workers, is a driver of smoking. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: 59 355 employees (34 865 men and 24 490 women) across multiple occupations who completed a self-reported questionnaire-based occupational stress survey between April 2016 and March 2017 in Niigata Prefecture. MAIN OUTCOME MEASURES: Stress scores for the Brief Job Stress Questionnaire subscales summed up after assigning high points for high stress and converted to Z-scores based on the mean of all participants. Heavy smokers (HS) smoked ≥15 cigarettes/day and light smokers (LS) smoked <15 cigarettes/day and were compared with non-smokers (NS) by gender. RESULTS: The main subscale items that were significantly associated with smoking status in both genders included 'physical burden', 'irritation' and 'physical symptoms'. In the analysis that included smoking intensity, the stress score for 'co-workers' support' was significantly lower for LS men than NS men (NS 0.091±0.98, LS -0.027±1.00, HS 0.033±0.99), and was significantly higher for HS women than NS women (NS -0.091±1.00, LS -0.080±1.05, HS 0.079±1.03). However, the stress score for 'co-workers' support' was low among LS women aged ≤39 years in the manufacturing industry. CONCLUSIONS: It was speculated that LS men and some LS women gained 'co-workers' support' using smoking as a communication tool while reducing the degree of smoking. The existence of such 'social smokers' suggested that to promote smoking cessation, measures are essential to improve the communication between workers in addition to implementing smoking restrictions in the workplace.

Importance of the Azole Moiety of Cimetidine Derivatives for the Inhibition of Human Multidrug and Toxin Extrusion Transporter 1 (hMATE1).

Herein, we describe the design and synthesis of cimetidine analogs, as well as their inhibitory activity toward the human multidrug and toxin extrusion transporter 1 (hMATE1), which is related to nephrotoxicity of drugs. Cimetidine is the histamine H2-receptor antagonist, but also inhibits hMATE1, which is known to cause renal impairment. We designed and synthesized cimetidine analogs to evaluate hMATE1 inhibitory activity to reveal whether the analogs could reduce the inhibition of hMATE1. The results showed that all analogs with an unsubstituted guanidino group exhibited hMATE1 inhibitory activity. On the other hand, there was a clear difference in the hMATE1 inhibitory activity for the other compounds. That is, compounds with a methylimidazole ring exhibited hMATE1 inhibition, while compounds with a phenyl ring did not. The results suggest that the ability to form hydrogen bonds at the azole moiety is strongly involved in the hMATE1 inhibition.

Involvement of Human Multidrug and Toxic Compound Extrusion (MATE) Transporters in Testosterone Transport.

Multidrug and toxic compound extrusion (MATE) transporters are primarily expressed in the kidneys and liver, where they contribute to the excretion of organic cations. Our previous study suggested that pig MATE2 (class III) participates in testosterone secretion from Leydig cells. In humans, it is unclear which MATE class is involved in testosterone transport. In this study, we aimed to clarify whether human MATE1 (hMATE1) or human MATE2K (hMATE2K) mediates testosterone transport. To confirm that testosterone inhibits transporter-mediated tetraethylammonium (TEA) uptake, a cis-inhibition assay was performed using cells that stably expressed hMATE1 or hMATE2K. Docking simulations were performed to characterize differences in the binding of hMATE1 and hMATE2K to testosterone. Transport experiments in LLC-PK1 cells that stably expressed hMATE1 were used to test whether hMATE1 mediates testosterone transport. We detected differences between the amino acid sequences of the substrate-binding sites of hMATE1 and hMATE2K that could potentially be involved in testosterone binding. Testosterone and estradiol inhibited TEA uptake mediated by hMATE1 but not that mediated by hMATE2K. Transport experiments in LLC-PK1 cells indicated that testosterone might be transported via hMATE1. This study suggested that hMATE1, but not hMATE2K, is involved in human testosterone transport.

Left ventricular free wall perforation by a right ventricular pacemaker lead: a case report.

BACKGROUND: Lead perforation is one of the major complications of pacemaker implantation, but cases of right ventricular (RV) lead perforation through the septum and left ventricle are rarely reported. We described a rare case of left ventricular (LV) free wall perforation by an RV lead and the management of this complication. CASE SUMMARY: An 84-year-old man was admitted with a dual-chamber pacemaker due to pacing failure caused by an RV lead fracture. New lead implantation was performed on the next day, but pacing failure occurred again on the second post-operative day (POD). We found the lead perforation on the fluoroscopy during temporary pacemaker insertion. Computed tomography scan and transthoracic echocardiogram showed that the added lead perforated through both the septum and LV free wall. A new lead was inserted on the fourth POD, and an off-pump open chest surgery for extraction of the penetrating lead was performed uneventfully on the 20th POD. DISCUSSION: We considered that some features of the lead (SelectSecure 3830-69, Medtronic) may be related to this complication, as the lead was very thin, had a non-retractable bare screw and was inserted with a dedicated delivery catheter. We have to be careful when performing implantation of this kind of lead to avoid such a rare complication.

Honeycomb-like structure in spontaneous recanalized coronary thrombus demonstrated by serial angiograms: a case report.

BACKGROUND: The honeycomb-like structure (HLS) is a rare cause of myocardial ischaemia characterized by multiple communicating channels divided by thin septa. The aetiology of this specific structure remains speculative. CASE SUMMARY: A 55-year-old man was admitted due to worsening effort angina during the previous 2 months. Diagnostic coronary angiography revealed occlusion of the distal right coronary artery (RCA) with good collateral flow from the left coronary artery. We considered this lesion as a recent total occlusion, and planned a percutaneous coronary intervention (PCI). At the time of PCI, 7 days after admission, an angiogram showed a spontaneous recanalization of the occlusive RCA. Intravascular ultrasound (IVUS) depicted a HLS at the recanalized lesion, including atherosclerotic stenosis. We managed these lesions with drug-eluting stents. DISCUSSION: A recanalized thrombus may manifest as a HLS. In this case, the patient suffered from worsening effort angina during the previous 2 months, we confirmed a spontaneous recanalization of the occluded coronary lesion by serial angiographic images, and observed HLS adjacent to the atherosclerotic attenuated plaque by using high-resolution IVUS. Recanalized organizing thrombus is considered an entity of HLS. However, all previous studies on the HLS in vivo have detected the structure in an already recanalized state. Therefore, the aetiology remained speculative and evidence has been indirect. This present case demonstrates that recanalized atherosclerotic thrombosis might be one of the causes of HLS.

Applicability of quantitative flow ratio for rapid evaluation of intermediate coronary stenosis: comparison with instantaneous wave-free ratio in clinical practice.

Quantitative flow ratio (QFR) is an image-based fractional flow reserve (FFR) computed by three-dimensional quantitative coronary angiography and estimated flow velocity. Several studies have reported that QFR was rapidly computed within approximately 5 min and had a good diagnostic performance as compared with FFR. However, studies comparing QFR with instantaneous wave-free ratio (iFR) as an index with a prognostic value comparable to that of FFR are limited. Thus, we investigated the applicability of QFR with respect to iFR, both being easy-to-measure indices not requiring pharmacological hyperaemic induction. We computed QFR in prospectively enrolled 150 coronary lesions (including 50 lesions for onsite QFR analysis) in consecutive patients with intermediate stenosis evaluated by iFR. The correlation and diagnostic performance of QFR were compared using iFR as a reference. The mean QFR and iFR were 0.81 ± 0.12 and 0.89 ± 0.11, respectively. QFR and iFR exhibited a good correlation in all subjects (R = 0.70, p < 0.0001) and the onsite-analysed vessels (R = 0.74, p < 0.0001). In the receiver-operating characteristics analysis, the area under the curve of QFR predicting iFR ≤ 0.89 was 0.91. Applying the cut-off value of QFR ≤ 0.80 and iFR ≤ 0.89, the sensitivity, specificity, positive and negative predictive values were 85%, 83%, 72%, and 91%, respectively, in all subjects, and 82%, 82%, 78%, and 85%, respectively, in the onsite-analysed vessels. QFR including onsite analysis demonstrated a good correlation with iFR and a diagnostic performance comparable to that of iFR in consecutive patients with intermediate coronary stenosis, suggesting its potential as a rapidly derived index for evaluating myocardial ischaemia in clinical settings.

Clinical Factors Relevant to the Recurrence of Atrial Tachyarrhythmia after Extensive Defragmentation Followed by Thoracic Vein Isolation.

INTRODUCTION: The efficacy of thoracic vein isolation (TVI), an approach to trigger atrial fibrillation (AF), for the management of AF has been established. Our goal was to identify the predictors for late recurrence of atrial tachyarrhythmias (ATAs), for which the patients and procedural and/or echocardiographic parameters were retrospectively analyzed. Although substrate modification in the atrium for the treatment of AF ablation remains controversial, the background associated with the outcome has not been fully investigated. We retrospectively studied 33 patients with paroxysmal AF and 21 with persistent AF undergoing defragmentation followed by TVI. We evaluated the late/early recurrences, defined as ATA at 3 months after/within the single procedure. METHODS AND RESULTS: During a median follow-up period of 22 (11-37) months, 28 patients (52%) experienced a late recurrence. There was a higher incidence of late recurrences in the patients with disease durations of ≥12.4 months, which was the optimal cut-off point measured in the receiver operating characteristic curve analysis, or in those with left atrial diameter >50 mm or with earlier recurrences than the others (19% versus 72%, p=0.01; 0% versus 37%, p=0.02; or 13% versus 53%, p<0.0001 by the log-rank test, respectively). Moreover, there was a trend toward a higher atrial tachycardia (AT)-free rate in the patients with AF termination during the procedure (75% versus 54%, p=0.07 by the log-rank test). A multivariate analysis based on the Cox proportional hazard model showed that disease duration ≥12.4 months or early recurrence was highly associated with the outcomes (HR 3.72, 95%CI 1.42-12.79, p<0.006; HR 4.80, 95%CI 2.24-10.56, p<0.0001). CONCLUSION: The AF duration and early ATA recurrence are the peri-procedural factors significantly relevant to the outcome after extensive defragmentation followed by TVI.

Occurrence of Potentially Lethal Arrhythmia due to Sudden Exposure of an Overt Accessory Pathway 8 Years After Catheter Ablation of a Concealed Accessory Pathway.

Although the efficacy of catheter ablation of the accessory pathway (AP) has been established, there are subgroups of APs with an intermittent conduction property, which is sometimes difficult to diagnose accurately. A 57-year-old man with a history of catheter ablation was referred to our clinic due to frequent faintness. He had undergone concealed AP ablation 8 years previously and bilateral circumferential pulmonary vein isolation (CPVI) 6 years previously. During regular electrocardiogram monitoring, it was suggested that irregular wide QRS tachycardia, which was considered to be atrial fibrillation with antegrade AP conduction, was the cause of the present symptoms. In the present electrophysiological study, we noticed a residual antegrade AP in the left lateral wall that was not observed during the previous session. We achieved abolition of overt accessory conduction, bilateral CPVI, and superior vena cava isolation with several radiofrequency applications without any recurrence. We also confirmed the absence of dormant conduction in the AP and the left atrium-PV connection with 20 mg adenosine triphosphate. This case demonstrated the possibility of sudden exposure of overt AP conduction late after catheter ablation of the concealed AP and the importance of confirming the absence of dormant conduction by means of adenosine triphosphate, which has the potential benefit of revealing latent AP conduction.

MFSD2B is a sphingosine 1-phosphate transporter in erythroid cells.

Sphingosine 1-phosphate (S1P) is an intercellular signaling molecule present in blood. Erythrocytes have a central role in maintaining the S1P concentration in the blood stream. We previously demonstrated that S1P is exported from erythrocytes by a glyburide-sensitive S1P transporter. However, the gene encoding the S1P transporter in erythrocytes is unknown. In this study, we found that the mouse erythroid cell line, MEDEP-E14, has S1P export activity and exhibits properties that are consistent with those of erythrocytes. Using microarray analysis of MEDEP-E14 cells and its parental cell line, E14TG2a, we identified several candidate genes for S1P export activity. Of those genes, only one gene, Mfsd2b, showed S1P transport activity. The properties of S1P release by MFSD2B were similar to those in erythrocytes. Moreover, knockout of MFSD2B in MEDEP-E14 cells decreased S1P export from the cells. These results strongly suggest that MFSD2B is a novel S1P transporter in erythroid cells.

Cause of the "power-on reset" phenomenon other than electric magnetic interference in a patient with a pacemaker.

A 67-year old male with a dual-chamber pacemaker visited for a regular check-up. An unfamiliar message emerged on the display just after placing the programmer wand. We could recognize that the pacemaker had already been in the safe back-up mode of DDI, and the programmer prompted a re-initialization request. We are so surprised because there was no indication of device malfunction the day before in daily monitoring and a 12-lead electrocardiogram revealed normally working in the DDD mode just before checking the device. The pacemaker was immediately re-programmed to the former setting. This phenomenon has not recurred for 12 months.

Successful elimination of premature ventricular contractions by ablation of origin and preferential pathway.

However, the common strategy for eliminating premature ventricular contractions (PVCs) is to explore the exit site and ablate, which may be difficult in some cases. The origin and the preferential pathway, an insulated pathway connected to the exit, may also become targets for eliminating PVCs.

Involvement of the Multidrug and Toxic Compound Extrusion Transporter in Testosterone Release from Cultured Pig Leydig Cells.

Testosterone is considered to be released from Leydig cells via passive diffusion because of its hydrophobicity; however, the exact mechanism underlying testosterone secretion and the transporter involved are both unknown. Multidrug and toxic compound extrusion (MATE) transporters are predominantly found in the kidneys and liver and are thought to function in the elimination of metabolic organic cations during the final step of excretion in the kidney. In contrast, mMATE2 has been shown to be predominantly expressed in testicular Leydig cells. Although the physiological function of mMATE2 in Leydig cells is unknown, we hypothesized that mMATE2 acts as a testosterone exporter and is responsible for the secretion of testosterone from Leydig cells. Therefore, in the present study, we investigated the involvement of the MATE transporter in testosterone secretion from pig Leydig cells. Immunohistochemical analysis with anti-pig MATE2 antiserum indicated that the MATE transporter is present in pig Leydig cells. Additionally, treatment with the MATE inhibitors cimetidine and pyrimethamine reduced the testosterone secretion from pig Leydig cells but increased the intracellular testosterone levels. Estradiol release and intracellular estradiol level induced by human chorionic gonadotropin (hCG) further increased with cimetidine treatment. These results indicated that testosterone produced by hCG treatment is secreted from Leydig cells via the MATE transporter; however, in the presence of cimetidine or pyrimethamine, this MATE transporter-mediated secretion was inhibited, resulting in increased intracellular testosterone levels and estradiol production in Leydig cells. Thus, the MATE transporter may be responsible for testosterone secretion from Leydig cells.

Applicability of 3-Dimensional Quantitative Coronary Angiography-Derived Computed Fractional Flow Reserve for Intermediate Coronary Stenosis.

BACKGROUND: Quantitative flow ratio (QFR) is a newly developed image-based index for estimating fractional flow reserve (FFR).Methods and Results:We analyzed 151 coronary arteries with intermediate stenosis in 142 patients undergoing wire-based FFR measurement using dedicated software. Predefined contrast flow QFR, which was derived from 3-dimensional quantitative coronary angiography (3-D QCA) withThrombolysis in Myocardial Infarction (TIMI) frame counts, was compared with FFR as a reference. QFR had good correlation (r=0.80, P<0.0001) and agreement (mean difference: 0.01±0.05) with FFR. After applying the FFR cut-off ≤0.8, the overall accuracy rate of QFR ≤0.8 was 88.0%. On receiver operating characteristics analysis, the area under the curve was 0.93 for QFR. In contrast, 3-D QCA-derived anatomical indices had insufficient correlation with FFR and diagnostic performance compared with QFR. CONCLUSIONS: QFR had good correlation and agreement with FFR and high diagnostic performance in the evaluation of intermediate coronary stenosis, suggesting that QFR may be an alternative tool for estimating myocardial ischemia.

Interesting electrophysiological findings in a patient with coexistence of atrial tachycardia originating from coronary sinus and slow-fast atrioventricular nodal reentrant tachycardia.

Slow-fast atrioventricular nodal tachycardia (AVNRT) has various electrophysiological aspects due to atrioventricular (AV) nodal physiology. In addition, concomitantly another form of arrhythmia with AVNRT, especially atrial tachycardia (AT), was an infrequent arrhythmia. A 38-year-old female with narrow QRS tachycardia underwent electrophysiological study due to frequent faintness. The electrophysiological study disclosed the coexistence of AT originating from coronary sinus (CS) with slow-fast AVNRT. We easily diagnosed AT originating from CS and terminated with several radiofrequency ablations (RFA) around CS. The diagnosis of slow-fast AVNRT, however, was somewhat difficult due to the following findings: (1) small amount of adenosine triphosphate (ATP) could terminate slow-fast AVNRT reproducibly; (2) we could provoke slow-fast AVNRT only by RV pacing with isoproterenol infusion. With other electrophysiological findings, we diagnosed slow-fast AVNRT. Radiofrequency energy was delivered initially in the posteroseptal region, followed by inside CS, and finally in the middle septal region, which completed the slow pathway ablation. After the procedure, we could never provoke these arrhythmias. .

Focal right atrial tachycardia with three foci in a patient with polymyositis.

Cardiac involvement secondary to polymyositis is not infrequent. In addition, it sometimes presents various forms of arrhythmia, including atrial tachycardia (AT). A 72-year-old female who had 5-years history of polymyositis was referred to our clinic with symptomatic supraventricular tachycardia with 2:1 atrioventricular conduction. Electrophysiological study revealed a total of three focal AT in right atrium with the origin of the basal right atrial appendage (AT1), coronary sinus ostium (AT2), and low lateral right atrium (AT3), respectively. Endocardial bipolar voltage mapping showed low voltage area in the limited area, partially overlapping with the focus of AT3. We finally terminated AT2 targeting an early fractionated potential and AT3 at early activation site with a support of flexibly-bended deflectable sheath while accidentally eliminating AT3 with the bumping of a catheter. With the additional applications, we completely eliminated all AT. AT were never provoked by any inductions with isoproterenol infusion. .

Successful angioplasty with intravascular ultrasound and optical frequency domain imaging guidance for tandem intramural hematoma caused by coronary artery spasm.

A 39-year-old woman with no coronary risk factors was admitted due to repetitive morning chest pain. Coronary angiography revealed subtotal occlusion of the distal obtuse marginal branch that was not recanalized by intracoronary nitroglycerin administration. Intravascular ultrasound and optical frequency domain imaging showed tandem intramural hematomas in the culprit vessel. We performed cutting balloon angioplasty successfully with dual intracoronary imaging modality guidance. The 4-month follow-up angiography revealed favorable vascular healing and the provocation test induced multiple spasms, including in the culprit vessel, by intracoronary acetylcholine administration. .

Fluorescence-based rapid measurement of sphingosine-1-phosphate transport activity in erythrocytes.

Sphingosine-1-phosphate (S1P) is present in the blood plasma and acts as a pivotal intercellular signal transmitter in the immune system by recruiting lymphocytes from the thymus and secondary lymphoid tissues. The plasma S1P concentration is maintained by the supply of S1P from erythrocytes. Previously, we showed that S1P release from erythrocytes is mediated by an ATP-dependent transporter. In this study, we attempted to establish a rapid and reliable method for measuring the S1P transport activity in erythrocytes by using a fluorescent S1P analog, 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD)-labeled S1P. NBD-S1P was released from erythrocytes in a time-dependent manner. The NBD-S1P release was reduced after exposure to glyburide, which is an inhibitor of the S1P transporter in erythrocytes. Moreover, the release of NBD-S1P and S1P from erythrocytes was competitively inhibited by intracellular S1P and NBD-S1P, respectively. These results showed that the erythrocyte S1P transporter exports NBD-S1P. We optimized the sample-preparation conditions and lipid extraction to increase the sensitivity of the assay. Furthermore, we successfully measured NBD-S1P release without lipid extraction by decreasing the concentration of BSA in the assay buffer to 0.1%. This method will be useful for the high-throughput screening of S1P transporter inhibitors using conventional fluorometers.