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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

High concentrations of beta-chemokines in BAL fluid of patients with diffuse panbronchiolitis.

BACKGROUND: T cells are important cellular components of bronchial inflammation in diffuse panbronchiolitis (DPB). beta-Chemokines such as RANTES (regulated on activation, normal T-cell expressed and secreted) and macrophage inflammatory peptide (MIP)-1alpha are closely related to the migration of inflammatory cells into the lung. In this study, we investigate the contribution of beta-chemokines to the accumulation of T cells in the lungs of patients with DPB. PATIENTS AND METHODS: We determined the levels of beta-chemokines in BAL fluid (BALF) and the correlation between these levels and T-cell subsets in BALF of 23 patients with DPB and 16 healthy subjects by sandwich enzyme-linked immunosorbent assay and flow cytometry. RESULTS: Percentages of CD3+ human leukocyte antigen (HLA)-DR+, CD8+, and CD8+HLA-DR+ cells in BALF of patients were significantly higher than in the control BALF. The absolute number of CD8+HLA-DR+ cells was also higher in BALF of patients than in the control BALF (p < 0.0001). Phenotypic analysis of CD4+ cells in BALF showed a similar percentage of CD4+CD45RA+ cells and CD4+CD29+ cells in patients and normal subjects. The concentrations of RANTES and MIP-1alpha in BALF of patients with DPB were significantly higher than in BALF of normal subjects (p < 0.05). In addition, there was a significant correlation between the absolute number or percentage of CD8+HLA-DR+ cells and MIP-1alpha concentration in BALF. CONCLUSIONS: Our results suggest that the interaction between activated CD8+ T cells and MIP-1alpha may contribute to the pathogenesis of DPB.

Elevated levels of soluble adhesion molecules in sera and BAL fluid of individuals infected with human T-cell lymphotropic virus type 1.

STUDY OBJECTIVE: T-lymphocytic alveolitis and increased levels of interleukin-2 receptor-alpha (CD25)-bearing T cells in the BAL fluid (BALF) of human T-cell lymphotropic virus type 1 (HTLV-1) carriers have been reported. Several chemokines and adhesion molecules may contribute to the accumulation of T lymphocytes in the lungs of HTLV-1 carriers. To clarify the correlation between adhesion molecules and HTLV-1-associated pulmonary disorders, we compared the distribution of T-lymphocyte subsets and soluble adhesion molecules, including soluble intercellular adhesion molecule (sICAM)-1, soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble L-selectin (sL-selectin), soluble E-selectin (sE-selectin), and soluble P-selectin (sP-selectin), in BALF and peripheral blood, between HTLV-1 carriers and noninfected healthy subjects. DESIGN: Flow cytometric analysis with monoclonal antibodies to cell-surface antigens was used to identify T-lymphocyte subsets in BALF samples from HTLV-1 carriers (n = 13) and noninfected healthy control subjects (n = 10). The levels of various soluble adhesion molecules in serum and in BALF were estimated by enzyme-linked immunosorbent assay. RESULTS: Higher percentages of CD3+ cells, CD3-expressing human leukocyte antigen-DR antigen, and CD3+CD25+ cells were detected in the BALF of HTLV-1 carriers than in that of noninfected control subjects. The concentrations of sICAM-1, sVCAM-1, sL-selectin, SE- selectin, and sP-selectin in the sera of patients were significantly higher than those in noninfected healthy control subjects. The concentration of sICAM-1 in the BALF of patients was significantly higher than that in noninfected healthy control subjects, and the concentration of sICAM-1 correlated well with the percentage of CD3+CD25+ cells. CONCLUSION: The concentrations of adhesion molecules in the sera of and sICAM-1 in the BALF of HTLV-1 carriers were significantly higher than those in noninfected individuals, and the concentration of sICAM-1 correlated well with the percentage of CD3+CD25+ cells in BALF. Our results suggest a possible interaction between activated T cells bearing CD25 and soluble adhesion molecules, especially sICAM-1, which may contribute to the pulmonary involvement in HTLV-1 carriers.

Effect of clearance of bacteria from the blood on the development of systemic bacteraemia in mice.

Clearance of various bacteria isolated from portal and systemic blood of mice was evaluated and compared. All portal blood strains, including Escherichia coli and enterococci were eliminated more rapidly from the circulation than were strains isolated from systemic blood, including Pseudomonas aeruginosa. With mannose-type lectin, mannose or fucose residues that mediated lectinophagocytosis were detected on the surfaces of most portal strains by agglutination tests. Blood clearance of Esch. coli H21 was inhibited by prior injection of mannose into mice, suggesting that the clearance of this strain was mediated by mannose-type lectin on the surface of tissue macrophages. However, no inhibition of clearance of any other strains was observed by the injection of mannose, galactose, or fucose into mice, nor by pre-incubation of bacteria with mannose. Blood clearance of some portal strains was significantly faster in CBA/J mice than in CBA/N mice with B cell immune deficiency, indicating that immunoglobulin was involved in their clearance. Among portal strains only enterococci showed high cell-surface hydrophobicity. These data suggest that initial bacteria blood clearance may be critical in determining whether latent portal bacteraemia progresses to systemic bacteraemia and that the rapid clearance of most strains is multifactorial.

Mortality rates amongst mice with endogenous septicaemia caused by Pseudomonas aeruginosa isolates from various clinical sources.

Mice that had been treated with cyclophosphamide and ampicillin were fed with Pseudomonas aeruginosa. These procedures induced an endogenous septicaemia under conditions mimicking the pathophysiology of the disease in man. This model was used to compare the mortality rates in mice infected with P. aeruginosa isolates from various clinical sources. Mortality rates in mice given isolates from blood cultures had a broad range (0-100%), but the mean rate was significantly higher than with isolates from other infection sites. Moreover, blood isolates persisted in the intestines of mice after oral inoculation, whereas most isolates from other sources were gradually eliminated. Most P. aeruginosa isolates from blood culture produced significantly higher levels of exotoxin A and total proteases than isolates from other infection sites. Amongst the blood isolates, all but one of the lethal strains produced large quantities of exotoxin A or total proteases or both. Taken together, the results suggest that the ability of P. aeruginosa to adhere to the intestinal tract and to produce high levels of exo-enzymes may contribute to the development of fatal septicaemia.

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.

Antimicrobial activity of superoxidized water.

We tested the antimicrobial activity of superoxidized water against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, Escherichia coli, Pseudomonas aeruginosa and Burkholderia cepacia. The number of bacteria was reduced below detection limit following incubation in superoxidized water for 10 s. The bactericidal activity of superoxidized water was similar to that of 80% ethanol, but superior to that of 0.1% chlorhexidine and 0.02% povidone iodine. We conclude that superoxidized water is a low cost but powerful disinfectant.

Infections caused by multiple strains of methicillin-resistant Staphylococcus aureus--a pressing epidemiological issue.

The genotype of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from several foci in the same patient was studied to identify the rate of infections caused by multiple MRSA strains during hospitalization. Twenty-one patients with MRSA bacteraemia and other specimens diagnosed between 1990-1994 were studied. Clinical data were retrospectively collected from the medical records. Genotyping of 113 MRSA isolates was performed by pulsed-field gel electrophoresis (PFGE), using the Gene Navigator System. More than one type of MRSA was detected from different foci in eight of 21 (38%) patients, and three types were identified in a single patient. Our results indicate that epidemiological investigations must be conducted carefully, especially in immunocompromised hosts with MRSA bacteraemia, as the probability of infection with multiple strains among these patients is relatively high.

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.

Amphotericin B-induced resistance to Pseudomonas aeruginosa infection in mice.

We evaluated the effects of amphotericin B (AmB) against Pseudomonas aeruginosa (P. aeruginosa) infection in mice. Pretreatment with 2 mg/kg of AmB 24 hours before infection significantly increased the survival rates of mice intraperitoneally infected with either P. aeruginosa or Escherichia coli. To evaluate the mechanism of this AmB-induced resistance to infection, we conducted a number of experiments. Peritoneal macrophages exposed in vitro to AmB showed superior bactericidal activity compared to that of control macrophages. Interleukin-1 production by peritoneal macrophages from mice pretreated with 2 mg/kg of AmB was significantly higher than that in control mice. Serum tumor necrosis factor level after intravenous injection of P. aeruginosa was also higher in mice pretreated with 2 mg/kg of AmB than in control mice. These data indicate that AmB induces resistance to P. aeruginosa in mice. Furthermore AmB-induced activation of peritoneal macrophages and their production of interleukin-1 and tumor necrosis factor appeared to play important roles in this phenomenon.