Influence of Different Undercut Depths of Clasp Fabricated by Selective Laser Melting on Retentive Force.

INTRODUCTION: The purpose of this study was to investigate the influence of undercut depths on abutment teeth regarding the retentive force of clasps fabricated through selective laser melting (SLM), and to compare them with conventional cast clasps. METHODS: Akers clasps made of cobalt chromium alloy were fabricated using the SLM method (SLM), and the retentive forces were compared with clasps made with the conventional cast method (Cast). Three undercut amounts (0.25 mm, 0.15 mm, and 0 mm) were applied on the abutment tooth. The specimens were subjected to 10,000 repetitive insertion/removal cycles. RESULTS: SLM-0.15 showed slightly lower initial retentive force than the Cast specimens, it remained within an acceptable range. During insertion/removal test, the SLM-0.15 specimen showed a significant difference between the initial retentive force and the retentive force after 5,000 cycles, indicating that SLM-0.15 was the least likely to change in retentive force within the parameters established in this study. The inner clasp surface on the SLM groups had higher surface roughness before testing compared to the Cast specimen. CONCLUSIONS: Akers clasps fabricated by SLM demonstrated optimal initial retentive forces with smaller undercuts than conventional Cast clasps, and the retentive forces changed less with repetitive insertion/removal.

Broad-spectrum antibiotic prescriptions are discontinued unevenly throughout the week.

In order to investigate prescribing patterns of in-hospital broad-spectrum antibiotics (antimeticillin-resistant Staphylococcus aureus drugs, carbapenems and piperacillin/tazobactam), data on the distribution of antibiotic initiation and discontinuation throughout the week were analysed at Osaka University Hospital, Japan. No significant differences in the number of initiations were found between weekdays. However, broad-spectrum antibiotics were disproportionately discontinued on Tuesdays or on the second day after a holiday. This study suggests that broad-spectrum antibiotics tend to be continued over weekends or holidays and discontinued thereafter; this is likely to be due to behavioural factors beyond medical indications, and needs to be addressed in future antimicrobial stewardship initiatives.

Hospital-by-hospital carbapenem use in Japan: a nationwide ecological study.

BACKGROUND: The Japanese healthcare system has been based on universal health coverage since 1961. Nationwide antimicrobial use on a hospital-by-hospital basis has not previously been recorded. OBJECTIVES: To determine the nationwide distribution of carbapenem use on a hospital-by-hospital basis and to build predictive models using available hospital data from Japan. METHODS: An ecological study was conducted using open data released from the Government of Japan. The distribution of days of therapy with carbapenem (per 1000 patient-days) was analysed and predictive models built. The top 1% heavy users by crude distribution and observed-per-predicted ratio distribution were listed and compared. The analysis was conducted in three subcategories stratified by hospital characteristics (tertiary, secondary acute care, and fee-for-service) and among patients in two age groups (16-65 and >65 years). FINDINGS: The median days of therapy in the group aged 16-65 years were 7.24 for tertiary hospitals, 3.28 for secondary acute care hospitals, and 1.42 for fee-for-service hospitals. The median days of therapy of the group aged >65 years were 17.28 for tertiary hospitals, 14.43 for secondary acute care hospitals, and 8.21 for fee-for-service hospitals. For multivariable linear regression analyses, each model selected a different combination of covariates from the potential predictors based on hospital characteristics. CONCLUSION: Because a single predictive model was not appropriate for all hospitals, tailored models are needed to identify hospitals that are heavy users of carbapenem. These findings may serve as a reference to support further research on antibiotic use in healthcare and aid future policies.

Trends in incidence and mortality of tuberculosis in Japan: a population-based study, 1997-2016.

Japan is still a medium-burden tuberculosis (TB) country. We aimed to examine trends in newly notified active TB incidence and TB-related mortality in the last two decades in Japan. This is a population-based study using Japanese Vital Statistics and Japan Tuberculosis Surveillance from 1997 to 2016. We determined active TB incidence and mortality rates (per 100 000 population) by sex, age and disease categories. Joinpoint regression was applied to calculate the annual percentage change (APC) in age-adjusted mortality rates and to identify the years showing significant trend changes. Crude and age-adjusted incidence rates reduced from 33.9 to 13.9 and 37.3 to 11.3 per 100 000 population, respectively. Also, crude and age-adjusted mortality rates reduced from 2.2 to 1.5 and 2.8 to 1.0 per 100 000 population, respectively. Average APC in the incidence and mortality rates showed significant decline both in men (-6.2% and -5.4%, respectively) and women (-5.7% and -4.6%, respectively). Age-specific analysis demonstrated decreases in incidence and mortality rates for every age category, except for the incidence trend in the younger population. Although trends in active TB incidence and mortality rates in Japan have favourably decreased, the rate of decline is far from achieving TB elimination by 2035.

Prevalence of, and risk factors for, carriage of carbapenem-resistant Enterobacteriaceae among hospitalized patients in Japan.

BACKGROUND: The prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has been reported to be lower in Japan than in many other countries. However, extensive surveillance for CRE carriage has not been performed in Japan. AIM: To investigate the prevalence of CRE carriage in Japan among convalescent patients considered to be at high risk of being CRE carriers using an improved selective culture medium. METHODS: A cross-sectional survey was conducted in 22 acute care hospitals (ACHs) and 21 long-term care hospitals (LTCHs) in northern Osaka from December 2015 to January 2016. Patients who used incontinence aids, an enteral feeding tube or a urinary catheter were enrolled. Faecal specimens were examined using the newly developed M-ECC for imipenemase (IMP)-producing CRE, which is the most prevalent form of CRE in Japan. The positive isolates were analysed by polymerase chain reaction and sequencing. Risk factors associated with carriage were analysed by logistic regression. FINDINGS: Among 1507 patients, 184 (12.2%) carried CRE. The percentage of positive patients was significantly higher in LTCHs (14.9%) than in ACHs (3.6%) (P<0.001). Risk factors for CRE carriage were longer hospital stay [odds ratio (OR) 2.59; 95% confidence interval (CI) 1.87-3.60], enteral feeding (OR 3.03, 95% CI 2.08-4.42) and antibiotic exposure (OR 2.00, 95% CI 1.40-2.87). Among the 233 CRE isolates identified, 223 were IMP producers; the remaining isolates did not produce carbapenemase. CONCLUSIONS: This is the first Japanese report to demonstrate the significant spread of CRE in both ACHs and LTCHs using an improved selective medium. A coordinated regional approach may help to prevent further spread.

Examination of factors that delay the elution of acetaminophen from over-the-counter drugs.

The information on the stability of medications is important to secure their quality. There is, however, little information about the stability of medications which assume to be kept by patients and customers. We previously showed that a delay in drug release occurs in some over-the-counter (OTC) drugs following storage in a high temperature, high humidity environment. In this study we prepared model tablet formulations containing an active ingredient and excipients to investigate the cause of this delayed release. The results reveal that delayed release occurs in preparations compounded with acetaminophen (AA) as the active ingredient and erythritol (ET) and crospovidone (CP) as excipients. In addition, ET deliquesces in a high humidity environment, then incorporates other particles during room temperature storage to form an aggregate. SEM observations and micropore distribution measurements conducted on OTC tablets that exhibit delayed release revealed that the number of intraparticle pores decreased after storage under high temperature, high humidity conditions. Thus, the delayed release by these pharmaceutical product formulations may be due to a change in the micropore structure both on the surface and within the particles, thereby decreasing the solvent infiltration pathways leading to the interior of the preparation.

Pre-emptive contact precautions for intubated patients reduced healthcare-associated meticillin-resistant Staphylococcus aureus transmission and infection in an intensive care unit.

Healthcare-associated infection by meticillin-resistant Staphylococcus aureus (MRSA) is still a great concern in an intensive care unit (ICU). Our surveillance data in the ICU revealed that intubated patients were at eight times higher risk of acquiring MRSA than non-intubated patients, so we hypothesised that pre-emptive contact precautions for all intubated patients would prevent healthcare-associated infection by MRSA in the ICU. Patients staying in our ICU for >2 days were included in this study. The study period was divided into two periods. During 2004 (1st period), contact precautions were performed only for patients with MRSA. During 2005-2007 (2nd period), contact precautions were applied to all intubated patients regardless of MRSA infection status. Patients were defined as MRSA-positive on admission when MRSA was detected by surveillance or clinical culture on enrolment. Other MRSA-positive results were defined as healthcare-associated MRSA (HA-MRSA) transmission. HA-MRSA infection was diagnosed according to the National Nosocomial Infections Surveillance Manual. The 1st period comprised 415 patients, and the 2nd period comprised 1280 patients. In intubated patients, HA-MRSA infection rate decreased significantly in the 2nd period (1st period 12.2%, 2nd period 5.6%; P=0.015). HA-MRSA infection of all patients decreased from 3.6 to 2.3 incidents per 1000 patient-days (P<0.05), despite a significant increase in the rate of patients MRSA positive on admission in the 2nd period (1st period 2.9%; 2nd period 6.1%). Pre-emptive contact precautions for intubated patients would be helpful in reducing HA-MRSA infection in ICU.

Effects of kaempferol on the mechanisms of drug resistance in the human glioblastoma cell line T98G.

Food contains components that may either increase or decrease the bioavailability of a drug. In particular, it is known that grapefruit juice and St. John's Wort induce drug interactions via an effect on the drug-metabolizing enzyme cytochrome P450 (CYP). However, interactions with membrane transporters, such as P-glycoprotein and multidrug resistance-related protein (MRP), may also influence drug bioavailability. The objective of the present study was to investigate the effects of kaempferol, a flavonoid present in food, on the cytotoxicity of anticancer drugs and the mechanisms of drug resistance in the human glioblastoma cell line T98G. Acute exposure to kaempferol inhibited the efflux of calcein, a substrate of MRP; however, chronic exposure caused no apparent effect on calcein efflux. The cytotoxicity of doxorubicin was not influenced by chronic exposure of cells to kaempferol, although that of cisplatin was significantly reduced. Multidrug resistance is often associated with increased levels of MRP1, glutathione S-transferase (GST) and activity by chronic exposure to kaempferol, although MRP2 protein levels are decreased. Accordingly, we hypothesized that the cytotoxicity of anticancer drugs that conjugate with glutathione and the substrate of MRPs may be influenced by long-term intake of drugs such as kaempferol, which are substrates of MRPs and GST.

Effectiveness of mechanochemical treatment with cyclodextrins on increasing solubility of glimepiride.

We investigated the enhancement of the solubility of glimepiride (GLM), a poorly water soluble anti-diabetes drug, by cogrinding it with various cyclodextrins (CDs) using a ball mill. The phase solubility profiles of GLM with beta-CD and its derivatives were classified as A(L)-type, indicating the formation of a 1 : 1 stoichiometric water-soluble complex. When GLM crystals were coground with beta-CD using a ball mill for 48 h, the aqueous solubility of GLM increased to approximately 250 microg/mL. The powder X-ray diffraction pattern showed that the peak intensity of crystalline GLM decreased after cogrinding. Endothermic peaks of around 208 degrees C, which were assigned to the fusion of GLM crystals, disappeared in the DSC measurement of the ground mixture. After cogrinding, two sharp peaks assigned to sulfonylurea and benzoyl carbonyl stretching bands varied to broaden the peak to around 1700 cm(-1) in the C=O stretching region. These results suggested the formation of a complex between GLM and beta-CD during cogrinding.

Construction of a model cell line for the assay of MDR1 (multi drug resistance gene-1) substrates/inhibitors using HeLa cells.

Cancer cells often become resistant to chemotherapy, and induction of the ABC transporter Multi-drug Resistance gene-1 (MDR1) is a major cause. We established a tool for high-throughput screening of substrates and inhibitors of MDR1, using transformed HeLa cells that over-express MDR1. The cDNA for human MDR1 was subcloned into the eukaryotic expression vector pBK-CMV to produce an MDR1 expression vector, pBK-CMV/MDR1. HeLa cells were transfected with pBK-CMV/MDR1 or the empty vector pBK-CMV. Transfection of the vector sequence for MDR1 and its expression were evaluated by genomic PCR and western blotting, respectively. The efficiency of the MDR1 transporter for pumping a substrate out of the transformed cells was evaluated using rhodamine123 (R-123), a mitochondrial dye that is also an MDR1 substrate. After treatment of the MDR1-expressing HeLa cells with MDR1 substrate vinblastin or inhibitors cyclosporin A and verapamil, the amount of R-123 retained in the cells was increased to 2 to 2.3 times the level in untreated MDR1-expressing HeLa cells. The transfection of empty pBK-CMV had no effect on the R-123 retention in HeLa cells, regardless of drug treatment. In conclusion, we have established a model human carcinoma cell line that expresses functional MDR1 and can be used to screen for substrates and inhibitors of MDR1.

Improvement of solubility of C70 by complexation with cyclomaltononaose (delta-cyclodextrin).

We investigated the solubilizing effects of cyclomaltononaose (delta-CD), a cyclic oligosaccharide composed of nine alpha-1,4-linked D-glucose units, on C70 by using the ball-milling method based on a solid-solid mechanochemical reaction. The complex between C70 and delta-CD was characterized by UV-VIS spectrometry and fast atom bombardment mass spectrometry (FAB-MS). Coloration of the C70/delta-CD system was red-brown in aqueous solution, and the UV-VIS spectrum was in agreement with that of C70 in hexane solution. The FAB-MS spectrum of the C70/delta-CD system showed a negative ion peak corresponding to the molecular weight of a complex between two delta-CD and one C70. These findings suggest that the solubilization of C70 in water was due to complex formation of C70 with delta-CD, and the stoichiometric ratio of this complex was 1: 2 (C70: delta-CD).

Intranuclear paracrystals observed in striated muscle specific LIM protein-deficient mouse cardiomyocytes.

A paracrystalline structure was observed within left ventricular cardiomyocyte nuclei of MLP(-/-) mice. The paracrystal possessed cross lines, approximately 8.0 micro m long and 0.3 micro m wide, with a slender spindle shape and a periodicity of 13 nm. Paracrystals were best observed along the longitudinal orientation of myofibrils and were detected in less than 10% of the nuclei observed. One dimension of the protein unit forming the paracrystal was 8.5 nm long. The electron density of the paracrystal appeared to be slightly higher than that of heterochromatin, suggesting that RNA-associated proteins are constituents of the paracrystal. This is the first report of intranuclear paracrystals in cardiomyocytes, which appear to be unique to MLP(-/-) mice.

Effects of macrolides on pneumolysin of macrolide-resistant Streptococcus pneumoniae.

To clarify the discrepancy between increasing resistance and conservative clinical effects of macrolides on macrolide-resistant Streptococcus pneumoniae, the authors evaluated the effects of sub-minimum inhibitory concentrations of macrolides on pneumolysin. In vitro, S. pneumoniae was incubated with 1, 2 and 4 microg.mL(-1) of clarithromycin (CLR) and azithromycin (AZM) for 8 h. Western blot analysis and haemolytic assay were performed to examine the production and activities of pneumolysin. In vivo, mice were infected with S. pneumoniae intra-nasally and treated with CLR (40 or 200 mg.kg(-1) twice daily) or AZM (40 or 200 mg.kg(-1) once daily) orally for 7 days. After 72 h post-infection, western blot analysis was performed to examine pneumolysin production in lungs. Survival rates were observed for 10 days. In vitro, every concentration of macrolide inhibited pneumolysin production more than the control. CLR (2 and 4 microg.mL(-1)) and AZM (4 microg.mL(-1)) reduced the pneumolysin activities more than the control. In vivo, macrolides (200 mg.kg(-1)) reduced pneumolysin in murine lungs more than the control. CLR (40 and 200 mg.kg(-1)) and AZM (200 mg.kg(-1)) improved the survival rates more than the control. The study results show that sub-minimum inhibitory concentrations of macrolides reduced pneumolysin. This might be related to the effectiveness of macrolides against pneumonia caused by high-level macrolide-resistant Streptococcus pneumoniae. Further investigations are necessary to evaluate the effects of macrolides on macrolide-resistant Streptococcus pneumoniae.

Immunokinetics in severe pneumonia due to influenza virus and bacteria coinfection in mice.

Coinfections of bacteria and influenza are a major cause of excessive mortality during influenza epidemics. However, the mechanism of the synergy between influenza virus and bacteria are poorly understood. In this study, mice were inoculated with influenza virus, followed 2 days later by inoculation with Streptococcus pneumoniae. The kinetics of viral titres, bacterial numbers and the immune response (cytokine and chemokine production) were also analysed. Short-term survival correlated with pathological changes in the lungs of infected mice. Influenza virus or S. pneumoniae infection alone induced moderate pneumonia; however, severe bronchopneumonia with massive haemorrhage in coinfected mice, which caused death of these mice approximately 2 days after inoculation with S. pneumoniae, was noted. Intrapulmonary levels of inflammatory cytokines/chemokines, type-1 T-helper cell cytokines and Toll-like receptors, and the related mitogen-activated protein kinase signalling molecules (phosphorylated extracellular signal-regulated kinase -1 and - 2, p38 and c-Jun N-terminal kinase), were increased in coinfected mice. These results suggest that immune mediators, including cytokines and chemokines, through Toll-like receptors/mitogen-activated protein kinase pathways, play important roles in the pathology of coinfection caused by influenza virus and Streptococcus pneumoniae.

Acute infection with influenza virus enhances susceptibility to fatal pneumonia following Streptococcus pneumoniae infection in mice with chronic pulmonary colonization with Pseudomonas aeruginosa.

We established a mouse model in which fatal pneumonia was induced by pneumococcal superinfection following influenza virus infection in chronic Pseudomonas aeruginosa infected mice. In this mouse model, influenza virus infection caused a significant increase in inflammatory cells, cytokines and severe tissue damage in the lungs of these P. aeruginosa infected mice, before pneumococcal infection. Intrapulmonary virus titres were significantly increased in mice with chronic P. aeruginosa infection, compared with control mice. Neutrophil function analysis showed significant reduction of myeloperoxidase (MPO) activity and lysozyme secretion by influenza virus infection in these mice. Our results suggest that influenza virus infection may play an important role in inducing pneumococcal pneumonia in chronic P. aeruginosa infected mice. Our results suggested that our mouse model is useful for investigating the pathogenesis of influenza virus infection in patients with chronic lung infection.

Virulence of metallo-beta-lactamase-producing Pseudomonas aeruginosa in vitro and in vivo.

We evaluated the virulence of Pseudomonas aeruginosa carrying bla(IMP), a metallo-beta-lactamase gene, and the efficacy of ceftazidime, imipenem-cilastatin, and ciprofloxacin in the endogenous bacteremia model. The presence of bla(IMP) did not practically change the virulence of the parent strain, and ciprofloxacin was effective against infection with P. aeruginosa carrying bla(IMP).

Long-term efficacy and safety of clarithromycin treatment in patients with diffuse panbronchiolitis.

Diffuse panbronchiolitis (DPB) can now be cured with long-term erythromycin treatment. Our group conducted a prospective open trial of long-term treatment with a macrolide antibiotic, clarithromycin. We studied ten patients who were treated for 4 years with oral clarithromycin (200 mg once a day). Pulmonary function test, blood gas analysis, comprehensive improvement score, and bacterial culture of sputum were examined at 3, 6, 12 months, and at 2, 3, 4 years after the initiation of the therapy. Pulmonary function improved in most of the patients within 6 months: the forced expiratory volume in one second showed a maximal increase from a mean (SE) value of 1.74 (0.12) l at baseline to 2.31 (0.22) l at 6 months (P < 0.01) and the volume (l) of forced vital capacity also showed a maximal increase within 6 months. The partial pressure of arterial oxygen at rest significantly increased at 3-6 months. The comprehensive improvement score also reached maximum within 6 months in nine of the patients. The majority of patients have developed sputum culture in which bacteria were negative within 6 months after the therapy. All of the patients maintained a stable condition with continued therapy, and no side effects of clarithromycin were observed during the study. This prospective study demonstrated that 6-month treatment with clarithromycin might be necessary to improve the clinical conditions of patients with DPB and the drug could be safely used for a long term.

Detection of Legionella DNA by PCR of whole-blood samples in a mouse model.

A detection system for Legionella DNA in blood samples based on the PCR was developed and evaluated in A/J mice with experimentally induced Legionella pneumonia. Primers were designed to amplify a 106 bp DNA fragment of the 16S rRNA gene specific to Legionella species. The PCR system could detect clinically relevant Legionella species including Legionella pneumophila, Legionella micdadei, Legionella bozemanae, Legionella dumoffii, Legionella longbeachae, Legionella gormanii and Legionella jordanis. The sensitivity of the PCR system was 20 fg extracted DNA. In the mouse model, the blood PCR was compared with results obtained by PCR on bronchoalveolar lavage fluid (BALF) samples, cultures of blood and BALF and detection of Legionella urinary antigen. Blood PCR was positive until 8 days after infection, while BALF PCR became negative on day 4. These results indicate that PCR using blood samples may be a useful, convenient and non-invasive method for the diagnosis of Legionella pneumonia.

Interaction of iodine with 2-hydroxypropyl-alpha-cyclodextrin and its bactericidal activity.

To obtain an effective iodine solution, the use of 2-hydroxypropyl-alpha-cyclodextrin (2-HP-alpha-CD) as solubilizer was examined in comparison with alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), potassium iodide (KI), and polyvinylpyrrolidone (PVP). The stability constants for inclusion of iodine with cyclodextrin and KI were ascertained by the solubility method. The apparent stability constants increased in the following order: KI < beta-CD < alpha-CD < 2-HP-alpha-CD. This order was nearly in accordance with that of the stabilization ability. The largest volatile depression effect was exhibited by 2HP-alpha-CD. The measurement of the minimum inhibitory concentration (MC) using Escherichia coli NIH-J-2 and Staphylococcus aureus FDA209P suggested that the bactericidal activity of the iodine/2-HP-alpha-CD system was the same as that of the iodine/alpha-CD, iodine/beta-CD, and iodine/PVP systems. The present results suggest that the combination of 2-HP-alpha-CD and iodine is useful for a stable and effective iodine solution.