Pigmentation level of human iPSC-derived RPE does not indicate a specific gene expression profile.

Retinal pigment epithelium (RPE) cells show heterogeneous levels of pigmentation when cultured in vitro. To know whether their color in appearance is correlated with the function of the RPE, we analyzed the color intensities of human-induced pluripotent stem cell-derived RPE cells (iPSC-RPE) together with the gene expression profile at the single-cell level. For this purpose, we utilized our recent invention, Automated Live imaging and cell Picking System (ALPS), which enabled photographing each cell before RNA-sequencing analysis to profile the gene expression of each cell. While our iPSC-RPE were categorized into four clusters by gene expression, the color intensity of iPSC-RPE did not project any specific gene expression profiles. We reasoned this by less correlation between the actual color and the gene expressions that directly define the level of pigmentation, from which we hypothesized the color of RPE cells may be a temporal condition not strongly indicating the functional characteristics of the RPE.

The backs of our eyes are lined with retinal pigment epithelial cells (or RPE cells for short). These cells provide nutrition to surrounding cells and contain a pigment called melanin that absorbs excess light that might interfere with vision. By doing so, they support the cells that receive light to enable vision. However, with age, RPE cells can become damaged and less able to support other cells. This can lead to a disease called age-related macular degeneration, which can cause blindness. One potential way to treat this disease is to transplant healthy RPE cells into eyes that have lost them. These healthy cells can be grown in the laboratory from human pluripotent stem cells, which have the capacity to turn into various specialist cells. Stem cell-derived RPE cells growing in a dish contain varying amounts of melanin, resulting in some being darker than others. This raised the question of whether pigment levels affect the function of RPE cells. However, it was difficult to compare single cells containing various amounts of pigment as most previous studies only analyzed large numbers of RPE cells mixed together. Nakai-Futatsugi et al. overcame this hurdle using a technique called Automated Live imaging and cell Picking System (also known as ALPS). More than 2300 stem cell-derived RPE cells were photographed individually and the color of each cell was recorded. The gene expression of each cell was then measured to investigate whether certain genes being switched on or off affects pigment levels and cell function. Analysis did not find a consistent pattern of gene expression underlying the pigmentation of RPE cells. Even gene expression related to the production of melanin was only slightly linked to the color of the cells. These findings suggests that the RPE cell color fluctuates and is not primarily determined by which genes are switched on or off. Future experiments are required to determine whether the findings are the same for RPE cells grown naturally in the eyes and whether different pigment levels affect their capacity to protect the rest of the eye.

DSP-0509, a systemically available TLR7 agonist, exhibits combination effect with immune checkpoint blockade by activating anti-tumor immune effects.

TLR7 is an innate immune receptor that recognizes single-stranded RNAs, and its activation leads to anti-tumor immune effects. Although it is the only approved TLR7 agonist in cancer therapy, imiquimod is allowed to be administered with topical formulation. Thus, systemic administrative TLR7 agonist is expected in terms of expanding applicable cancer types. Here, we demonstrated the identification and characterization of DSP-0509 as a novel small-molecule TLR7 agonist. DSP-0509 is designed to have unique physicochemical features that could be administered systemically with a short half-life. DSP-0509 activated bone marrow-derived dendritic cells (BMDCs) and induced inflammatory cytokines including type I interferons. In the LM8 tumor-bearing mouse model, DSP-0509 reduced tumor growth not only in subcutaneous primary lesions but also in lung metastatic lesions. DSP-0509 inhibited tumor growth in several syngeneic tumor-bearing mouse models. We found that the CD8+ T cell infiltration of tumor before treatment tended to be positively correlated with anti-tumor efficacy in several mouse tumor models. The combination of DSP-0509 with anti-PD-1 antibody significantly enhanced the tumor growth inhibition compared to each monotherapy in CT26 model mice. In addition, the effector memory T cells were expanded in both the peripheral blood and tumor, and rejection of tumor re-challenge occurred in the combination group. Moreover, synergistic anti-tumor efficacy and effector memory T cell upregulation were also observed for the combination with anti-CTLA-4 antibody. The analysis of the tumor-immune microenvironment by using the nCounter assay revealed that the combination of DSP-0509 with anti-PD-1 antibody enhanced infiltration by multiple immune cells including cytotoxic T cells. In addition, the T cell function pathway and antigen presentation pathway were activated in the combination group. We confirmed that DSP-0509 enhanced the anti-tumor immune effects of anti-PD-1 antibody by inducing type I interferons via activation of dendritic cells and even CTLs. In conclusion, we expect that DSP-0509, a new TLR7 agonist that synergistically induces anti-tumor effector memory T cells with immune checkpoint blockers (ICBs) and can be administered systemically, will be used in the treatment of multiple cancers.

Detection and discrimination of multiple strains of Zika virus by reverse transcription-loop-mediated isothermal amplification.

BACKGROUND: Monitoring both invasion of Zika virus disease into free countries and circulation in endemic countries is essential to avoid a global pandemic. However, the difficulty lies in detecting Zika virus due to the large variety of mutations in its genomic sequence. To develop a rapid and simple method with high accuracy, reverse transcription-loop-mediated isothermal amplification (RT-LAMP) was adopted for the detection of Zika virus strains derived from several countries. RESULTS: Common primers for RT-LAMP were designed based on the genomic sequences of two standard Zika strains: African lineage, MR-766, and Asian lineage, PRVABC59. RT-LAMP reactions using a screened primer set, targeting the NS3 region, detected both Zika virus strains. The minimum detectable quantity was 3 × 10-2 ng of virus RNA. Measurable lag of reaction times among strains was observed. The RT-LAMP method amplified the target virus sequence from the urine and serum of a patient with a travel history in the Caribbean Islands and also provided a prediction about which lineage of Zika virus strain was present. CONCLUSIONS: The RT-LAMP method using a well-optimized primer set demonstrated high specificity and sensitivity for the detection of Zika virus strains with a variety in genomic RNA sequences. In combination with the simplicity of LAMP reaction in isothermal conditions, the optimized primer set established in this study may facilitate rapid and accurate diagnosis of Zika fever patients with virus strain information.

Seroprevalence and associated factors of Toxoplasma gondii among HIV-infected patients in Tokyo: A cross sectional study.

HIV infection, in particular in patients with developing AIDS, carries a risk of causing toxoplasmosis with encephalitis, which is mostly caused by a form (bradyzoite) of the protozoan parasite Toxoplasma gondii. HIV/AIDS in Japan has been recognized as a serious health issue in recent years. In this study, to elucidate T. gondii seroprevalence in HIV-positive patients in Japan and associated characteristics with Toxoplasma parasite infection, the titer of T. gondii IgG (Tg-IgG) was measured in 399 HIV-positive patients who visited a hospital in Tokyo, Japan, between 2015 and 2017. A questionnaire survey was also conducted to investigate associations between lifestyle and customs. As a result, the overall prevalence of Tg-IgG-positive serum was 8.27% (33 cases of 399). All the cases positive for Tg-IgG were confirmed using the Sabin-Feldman dye test; the titers between each examination correlated robustly (p < 0.001, r = 0.6). A correlation between Toxoplasma infection rate and age was determined (p < 0.001), whereas there was no significant correlation with lifestyle customs such as consuming undercooked meat or owning a cat. An association between Toxoplasma infection and experience of dwelling in the Hokkaido area, the northern part of Japan, was observed (p = 0.001). These results suggested that the proportion of those who were previously exposed to Toxoplasma parasites in the HIV-positive population has been maintained at a similar level as that of the HIV-negative population in Japan, providing clear information about the potential risk of toxoplasmic encephalitis.

Metastatic infection during Staphylococcus aureus bacteremia.

Staphylococcus aureus causes various infections, including skin and soft tissue infections and pneumonia via both, community-associated and nosocomial infection. These infectious diseases can lead to bacteremia, and may subsequently result in metastatic infections in several cases. Metastatic infections are critical complications in patients with S. aureus bacteremia, since the optimal duration of the antimicrobial treatment differs in patients with and without metastatic infection. Notably, two weeks of antimicrobial treatment is recommended in case of uncomplicated S. aureus bacteremia, whereas in patients with S. aureus bacteremia-associated endocarditis or vertebral osteomyelitis, six weeks of antimicrobial administration is vital. In addition, misdiagnosis or insufficient treatment in metastatic infection is associated with poor prognosis, functional disability, and relapse. Although echocardiography is recommended to examine endocarditis in the patients with S. aureus bacteremia, it remains unclear which patients should undergo additional examinations, such as CT and MRI, to detect the presence of other metastatic infections. Clinical studies have revealed that permanent foreign body and persistent bacteremia are predictive factors for metastatic infections, and experimental studies have demonstrated that the virulence factors of S. aureus, such as fnbA and clfA, are associated with endocarditis; however, these factors are not proven to increase the risk of metastatic infections. In this review, we assessed the incidence, predictive factors, diagnosis, and treatment for metastatic infections during S. aureus bacteremia.

Age-Associated Theophylline Metabolic Activity Corresponds to the Ratio of 1,3-Dimethyluric Acid to Theophylline in Mice.

Age is known as one of influencing factor for theophylline (TP)-metabolizing capacity. In a previous our study, the ratio of TP and its major metabolite 1,3-dimethyluric acid (DMU) in serum (DMU/TP) is a useful index to estimate TP-metabolizing capacity, and this value markedly increased by influencing factor, such as the history of smoking. However, it is unknown whether DMU/TP values in serum reflect age-associated changes of TP-metabolizing capacity. In this study, the effect of age on the DMU/TP values in serum were investigated using mice of different age due to the limited blood sampling in human. The concentrations of TP and its metabolites in mouse serum were simultaneously measured using HPLC. As observed in human serum, serum TP concentrations were closely correlated with DMU concentration in mice, which indicates that the DMU/TP ratio is a good indicator of TP metabolic ability in mice. When TP was administered subcutaneously in 2-28-week-old mice, age-associated changes in the DMU/TP ratio in mice were observed. In conclusion, age-associated changes in TP-metabolizing capacity can be estimated by the DMU/TP ratio in serum.

Seroprevalence of Toxoplasma gondii in wild sika deer in Japan.

Toxoplasmosis is a food-borne infection that is widespread around the world, causing congenital disorders and opportunistic infections. Ingestion of undercooked meat is one of the risk factors for infection with the causative agent, Toxoplasma gondii. Japanese people occasionally eat rare meat as a traditional cuisine style called "Sashimi". A rapid increase in venison consumption in Japan has occurred mainly due to enhanced population control of wild Japanese deer (Cervus nippon) in recent decades. In particular, Yezo-sika deer (C. n. yesoensis) in Hokkaido (the northernmost and largest prefecture in Japan) is frequently supplied to markets as branded game/bushmeat. To study the possible burden of Toxoplasma gondii among wild Yezo-sika deer, plasma samples of Yezo-sika deer hunted during two seasons, 2010-2012, in Eastern Hokkaido were investigated. A total 80 samples were examined using the Sabin-Feldman dye test, which is highly specific and sensitive for identifying the development and persistence of antibodies after primary Toxoplasma infection, demonstrating that 38 cases (47.5%) were seropositive (cut-off titer <1:16). Antibody prevalence of T. gondii in female deer was higher than in males. Adult deer aged 3 years or over showed higher seroprevalence compared with younger animals. The overall seroprevalence fluctuated significantly according to the season when the deer were hunted. These results indicated widespread infection of T. gondii among Japanese wild Yezo-sika deer, suggesting that both appropriate handling and treatment of bushmeat are required to prevent food-borne toxoplasmosis in Japan.

Surveillance on susceptibility of strains isolated from pediatric infections.

During the period from January to December 2015, 104 Streptococcus pneumoniae strains, 129 Haemophilus influenzae strains and 54 Moraxella catarrhalis strains isolated from clinical specimens of pediatric infections in the national 16 institutions, studied susceptibilities of total 28 antibiotics, the capsular serotype for S. pneumoniae, the capsular b type and ß-lactamase production capability for H. influenzae, and the ß-lactamase production capability for M. catarrhalis were measured. In S. pneumoniae, the results showed that 68 strains (65.4%) were PSSP, 32 (30.8%) were PISP, and 4 (3.8%) were PRSP. The susceptibilities of TBPM and GRNX among oral antibiotics, and PAPM among injectable antibiotics demonstrated the lowest value with MIC90 ≤ 0.06 µg/mL. The most frequent distribution of S. pneumoniae serotypes was seen in 15B, followed by 19A, and 35B. Serotype strains contained in 13-valent pneumococcal conjugate vaccine (PCV13) were 19 strains (18.3%). In H. influenzae, the results showed that BLNAS accounted for 40 strains (31.0%), BLNAI for 28 strains (21.7%), BLNAR for 47 strains (36.4%), ß-lactamase producing for 14 strains (10.8%). The susceptibilities of quinolones demonstrated the lowest outcome among oral antibiotics with MIC90 ≤ 0.06 µg/mL, and CTRX and TAZ/PIPC (TAZ4 fixed) among injectable antibiotics with MIC of 0.25 µg/mL. There was no detection of capsular type b strains. In M. catarrhalis, all the isolates were ß-lactamase producing strains. The susceptibilities of TBPM, CPFX, TFLX and GRNX among oral antibiotics, and TAZ/PIPC (TAZ4 fixed), PAPM, MEPM and DRPM among injectable antibiotics demonstrated the lowest outcome with MIC of ≤0.06 µg/mL.

Detection of bacterial DNA from central venous catheter removed from patients by next generation sequencing: a preliminary clinical study.

BACKGROUND: Catheter-related infection (CRI) is one of the serious challenges in clinical practice. This preliminary clinical study aimed to examine whether next-generation sequencing (NGS) targeting 16S rDNA, which was PCR-amplified directly from the tip of a central venous catheter (CVC), can be used to identify causative pathogens in CRI, compared to the culture method. METHODS: Hospitalized patients, from whom a CVC had just been removed, were prospectively enrolled and divided into the CRI-suspected and routine removal groups. DNA was extracted from the sonication fluid of CVC specimens derived from patients. For analysis of bacterial composition by NGS, the V3-V4 fragments of bacterial 16S rDNA were PCR-amplified, followed by index PCR and paired-end sequencing on an Illumina MiSeq device. Conventional culture methods were also performed in the CRI-suspected group. RESULTS: Of CVCs collected from the 156 enrolled patients (114 men; mean age 65.6 years), a total of 14 specimens [nine out of 31 patients suspected with CRI and five out of 125 patients without infection symptoms (routine removal group)] were PCR-positive. In five patients with definite CRI, Staphylococcus was the most frequently detected genus by NGS (4/5 specimens), although no pathogens were detected by NGS in the one remaining specimen. The genera identified by NGS were consistent with those from conventional culture tests. There was high agreement between NGS and the culture method in the CRI-suspected group, with sensitivity and specificity values of 80.0% and 76.9%, respectively; meanwhile, the false-positive rate of NGS was as low as 4.0% in the routine removal group. Moreover, several genera, besides the genus identified by culture test, were detected in each patient with definite CRI and surgical site infection (SSI). Additionally, in one patient with SSI, Enterococcaceae were detected not only by NGS but also by abdominal abscess drainage culture. CONCLUSIONS: NGS targeting 16S rDNA was able to analyze the bacterial composition of CVC specimens and detect causative pathogens in patients with CRI and was therefore suggested as a promising diagnostic tool for CRI.

Automated adherent cell elimination by a high-speed laser mediated by a light-responsive polymer.

Conventional cell handling and sorting methods require manual labor, which decreases both cell quality and quantity. To purify adherent cultured cells, cell purification technologies that are high throughput without dissociation and can be utilized in an on-demand manner are expected. Here, we developed a Laser-induced, Light-responsive-polymer-Activated, Cell Killing (LiLACK) system that enables high-speed and on-demand adherent cell sectioning and purification. This system employs a visible laser beam, which does not kill cells directly, but induces local heat production through the trans-cis-trans photo-isomerization of azobenzene moieties. Using this system in each passage for sectioning, human induced pluripotent stem cells (hiPSCs) maintained their pluripotency and self-renewal during long-term culture. Furthermore, combined with deep machine-learning analysis on fluorescent and phase contrast images, a label-free and automatic cell processing system has been developed by eliminating unwanted spontaneously differentiated cells in undifferentiated hiPSC culture conditions.

Broad impact of extracellular DNA on biofilm formation by clinically isolated Methicillin-resistant and -sensitive strains of Staphylococcus aureus.

Staphylococcus aureus is a major causative agent for biofilm-associated infections. Inside biofilms, S. aureus cells are embedded in an extracellular matrix (ECM) composed of polysaccharide-intercellular adhesins (PIA), proteins, and/or extracellular DNA (eDNA). However, the importance of each component and the relationship among them in biofilms of diverse strains are largely unclear. Here, we characterised biofilms formed by 47 S. aureus clinical isolates. In most (42/47) of the strains, biofilm formation was augmented by glucose supplementation. Sodium chloride (NaCl)-triggered biofilm formation was more prevalent in methicillin-sensitive S. aureus (15/24) than in methicillin-resistant strain (1/23). DNase I most effectively inhibited and disrupted massive biofilms, and Proteinase K was also effective. Anti-biofilm effects of Dispersin B, which cleaves PIA, were restricted to PIA-dependent biofilms formed by specific strains and showed significant negative correlations with those of Proteinase K, suggesting independent roles of PIA and proteins in each biofilm. ECM profiling demonstrated that eDNA was present in all strains, although its level differed among strains and culture conditions. These results indicate that eDNA is the most common component in S. aureus biofilms, whereas PIA is important for a small number of isolates. Therefore, eDNA can be a primary target for developing eradication strategies against S. aureus biofilms.

Severe Thrombocytopenia During Dolutegravir-containing Antiretroviral Therapy.

A 56-year-old Japanese man diagnosed with acquired immunodeficiency syndrome, Pneumocystis jirovecii pneumonia and cytomegalovirus infection presented with thrombocytopenia after starting antiretroviral therapy, which included dolutegravir (DTG). Although good control of the human immunodeficiency virus and cytomegalovirus infections was achieved, the patient's thrombocytopenia persisted. The patient's platelet count decreased to ≤50,000/µL even after the cessation of valganciclovir, which can cause bone marrow suppression. At five months after starting antiretroviral therapy, DTG was replaced by ritonavir-boosted darunavir. Soon after, his platelet count improved and was maintained at a level of >100,000/µL. This is the first reported case of severe thrombocytopenia during DTG-containing antiretroviral therapy.

Helicobacter cinaedi bacteremia with cellulitis in a living-donor kidney transplant recipient identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry: a case report.

BACKGROUND: Helicobacter cinaedi causes bacteremia and cellulitis, mainly in immunocompromised patients. We report a rare case of H. cinaedi bacteremia with cellulitis in a living-donor kidney transplant recipient identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). A 54-year-old Asian man with IgA nephropathy underwent living-donor kidney transplantation 14 years previously. He was admitted to our hospital for evaluation of fever and multifocal cellulitis. H. cinaedi was isolated and identified from the patient's blood using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and gyrase subunit B-targeted polymerase chain reaction assays. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry has proven over the years to be a rapid and accurate universal method for the identification of microorganisms. CONCLUSIONS: The combined use of these detection methods enabled the appropriate administration of 6 weeks of antibiotic therapy. The patient recovered completely, with no recurrence.

Associations of HIV testing and late diagnosis at a Japanese university hospital.

OBJECTIVES: This study was conducted to clarify the rate of late diagnosis of HIV infection and to identify relationships between the reasons for HIV testing and a late diagnosis. METHODS: This retrospective cohort study was conducted among HIV-positive patients at the Jikei University Hospital between 2001 and 2014. Patient characteristics from medical records, including age, sex, sexuality, the reason for HIV testing and the number of CD4-positive lymphocytes at HIV diagnosis, were assessed. RESULTS: A total of 459 patients (men, n=437; 95.2%) were included in this study and the median age at HIV diagnosis was 36 years (range, 18-71 years). Late (CD4 cell count <350/mm3) and very late (CD4 cell count <200/mm3) diagnoses were observed in 61.4% (282/459) and 36.6% (168/459) of patients, respectively. The most common reason for HIV diagnosis was voluntary testing (38.6%, 177/459 patients), followed by AIDS-defining illness (18.3%, 84/459 patients). Multivariate analysis revealed a significant association of voluntary HIV testing with non-late and non-very-late diagnoses and there was a high proportion of AIDS-defining illness in the late and very late diagnosis groups compared with other groups. Men who have sex with men was a relative factor for non-late diagnosis, whereas nonspecific abnormal blood test results, such as hypergammaglobulinemia and thrombocytopenia, were risk factors for very late diagnosis. CONCLUSIONS: Voluntary HIV testing should be encouraged and physicians should screen all patients who have symptoms or signs and particularly hypergammaglobulinemia and thrombocytopenia, that may nonspecifically indicate HIV infection.

Associations of HIV testing and late diagnosis at a Japanese university hospital

OBJECTIVES: This study was conducted to clarify the rate of late diagnosis of HIV infection and to identify relationships between the reasons for HIV testing and a late diagnosis. METHODS: This retrospective cohort study was conducted among HIV-positive patients at the Jikei University Hospital between 2001 and 2014. Patient characteristics from medical records, including age, sex, sexuality, the reason for HIV testing and the number of CD4-positive lymphocytes at HIV diagnosis, were assessed. RESULTS: A total of 459 patients (men, n=437; 95.2%) were included in this study and the median age at HIV diagnosis was 36 years (range, 18-71 years). Late (CD4 cell count <350/mm3) and very late (CD4 cell count <200/mm3) diagnoses were observed in 61.4% (282/459) and 36.6% (168/459) of patients, respectively. The most common reason for HIV diagnosis was voluntary testing (38.6%, 177/459 patients), followed by AIDS-defining illness (18.3%, 84/459 patients). Multivariate analysis revealed a significant association of voluntary HIV testing with non-late and non-very-late diagnoses and there was a high proportion of AIDS-defining illness in the late and very late diagnosis groups compared with other groups. Men who have sex with men was a relative factor for non-late diagnosis, whereas nonspecific abnormal blood test results, such as hypergammaglobulinemia and thrombocytopenia, were risk factors for very late diagnosis. CONCLUSIONS: Voluntary HIV testing should be encouraged and physicians should screen all patients who have symptoms or signs and particularly hypergammaglobulinemia and thrombocytopenia, that may nonspecifically indicate HIV infection.

Pharmacokinetics and brain penetration of carbapenems in mice.

An adverse effect associated with the administration of carbapenems is central nervous system (CNS) toxicity, with higher brain concentrations of carbapenems being linked to an increased risk of seizures. However, the pharmacokinetics and brain penetration of carbapenems have not yet been examined. Thus, the aim of this in vivo investigation was to determine the pharmacokinetics and brain penetration of carbapenems in mice. Blood samples and brain tissue samples were obtained 10, 20, 30, 60, and 120 min after the subcutaneous administration of carbapenems (91 mg/kg). We obtained the following values for the pharmacokinetic parameters of carbapenems in mice: 1.20-1.71 L/h/kg for CLtotal/F, 1.41-2.03 h(-1) for Ke, 0.34-0.51 h for T1/2, 0.66-0.95 L/kg for Vss/F, 0.49-0.73 h for MRT, 83.46-110.58 µg/mL for Cmax, plasma, and 0.28-0.83 µg/g for Cmax, brain tissue. The AUC0-∞ of the carbapenems tested in plasma were in the following order: doripenem > meropenem > biapenem > imipenem, and in brain tissue were: imipenem > doripenem > meropenem > biapenem. The degrees of brain tissue penetration, defined as the AUC0-∞, brain tissue/fAUC0-∞, plasma ratio, were 0.016 for imipenem, 0.004 for meropenem, 0.002 for biapenem, and 0.008 for doripenem. The results of the present study demonstrated that, of the carbapenems examined, imipenem penetrated brain tissue to the greatest extent.

Pharmacokinetics and skin-tissue penetration of daptomycin in rats.

BACKGROUND: Daptomycin is recommended for complicated skin and skin-structure infections. However, information on the penetration of daptomycin into skin is limited. Therefore, the aim of this in vivo investigation was to determine the pharmacokinetics and skin penetration of daptomycin in rats. MATERIALS AND METHODS: Concentrations of daptomycin were determined by high-performance liquid chromatography. A noncompartmental pharmacokinetic analysis was conducted to estimate the rate and extent of daptomycin penetration from the systemic circulation into skin tissue. Since protein binding of daptomycin in rat serum was 89.3%, the free maximum concentration (Cmax) and free area under the curve from time 0 to infinity (AUC0-∞) for plasma were calculated as follows: fCmax, plasma = (1 - 0.893) × Cmax, plasma, fAUC0-∞, plasma = (1 - 0.893) × AUC0-∞, plasma. RESULTS: The following values (mean ± standard deviation) were obtained: 0.06±0 L/h/kg for total clearance (CLtotal), 0.44±0.06 hours for elimination-rate constant, 1.58±0.23 hours for half-life, 0.14±0.02 L/kg for steady-state volume distribution, and 2.28±0.33 hours for mean residence time. Time to Cmax was 3.0 hours for plasma and skin tissue. Cmax and AUC0-∞ for plasma were 175.8±5.1 µg/mL and 811.8±31.9 µg × h/mL, respectively. Cmax and AUC0-∞ for skin tissue were 19.1±1.7 µg/mL and 113.9±21.8 µg × h/mL, respectively. Furthermore, fCmax and fAUC0-∞ for plasma were 18.8 µg/mL and 86.9 µg × h/mL, respectively. The degrees of skin-tissue penetration, defined as the Cmax, skin tissue/fCmax, plasma ratio and AUC0-∞, skin tissue/fAUC0-∞, plasma ratio, were 1.0 and 1.3, respectively. CONCLUSION: Daptomycin exhibited good penetration into skin tissue, supporting its use for the treatment of complicated skin and skin-structure infections. However, further studies are needed in infected patients in order to investigate the relationship between the antimicrobial efficacy of daptomycin and its drug concentrations in skin tissues.

DSR-71167, a novel mineralocorticoid receptor antagonist with carbonic anhydrase inhibitory activity, separates urinary sodium excretion and serum potassium elevation in rats.

Mineralocorticoid receptor (MR) antagonists, such as spironolactone (SPI) and eplerenone (EPL), are useful for treating hypertension and heart failure. However, these two agents have the serious side effect of hyperkalemia. We hypothesized that adding the ability to inhibit carbonic anhydrase (CA) would reduce the risk of hyperkalemia associated with MR antagonists. We investigated the profiles of DSR-71167 [2-([(2,2-difluoroethyl)amino]methyl)-2'-fluoro-N-(3-methoxy-4-sulfamoylphenyl)biphenyl-4-carboxamide hydrochloride; an MR antagonist with weak CA inhibitory activity] with regard to antimineralocorticoid actions by examining relationships between the urinary excretion of sodium (index of antimineralocorticoid action) in deoxycorticosterone acetate-treated rats and elevation of serum levels of potassium in potassium-loaded rats compared with a DSR-71167 derivative without CA inhibition (2-(hydroxymethyl)-N-[4-(methylsulfonyl)phenyl]-2'-(trifluoromethyl)biphenyl-4-carboxamide), SPI, and EPL. DSR-71167 dose-dependently increased urinary excretion of sodium in deoxycorticosterone acetate-treated rats without elevating serum levels of potassium in potassium-loaded rats. 2-(Hydroxymethyl)-N-[4-(methylsulfonyl)phenyl]-2'-(trifluoromethyl)biphenyl-4-carboxamide, SPI, and EPL elevated serum levels of potassium significantly in potassium-loaded rats at doses that increased MR inhibitory activity. We confirmed that DSR-71167 significantly increases urinary bicarbonate and decreases blood bicarbonate, as pharmacodynamic markers of CA inhibition, in intact rats. Chronic DSR-71167 administration showed antihypertensive effects in high salt-loaded Dahl hypertensive rats. These results demonstrate that DSR-71167 is a novel type of MR antagonist, with CA inhibitory activity, which is expected to become a safer MR antagonist with a low potential risk for hyperkalemia.

Pharmacokinetics and dosing estimation of meropenem in Japanese patients receiving continuous venovenous hemodialysis.

The pharmacokinetics of meropenem have not yet been examined in Japanese patients receiving Continuous venovenous hemodialysis (CVVHD). The aim of this clinical investigation was to determine the pharmacokinetic parameters of meropenem in critically ill patients receiving CVVHD in order to estimate dosing regimens for the patient population in Japan. The values of pharmacokinetic parameters were 17.5 ± 5.6 l for V1, 1.27 ± 0.38 h(-1) for K12, 0.71 ± 0.40 h(-1) for K21 and 0.17 ± 0.02 h(-1) for K10. Based on these mean parameters (V1, K12, K21 and K10), time above MIC (T > MIC) values were estimated at different MICs using various meropenem regimens. For bacteria with a meropenem MIC of ≤ 2 µg/ml, a dosing regimen of 0.25 g every 24 h achieved more than 40% T > MIC. For a MIC of 4 µg/ml, all the regimens tested, except for 0.25 g every 24 h, achieved more than 40% T > MIC. For a MIC of 16 µg/ml, dosing regimens of 0.5 g every 8 h, 1 g every 12 h, and 1 g every 8 h achieved 40% T > MIC, reaching the pharmacokinetic-pharmacodynamic target range. This is the first study to examine the pharmacokinetics of meropenem under a CVVHD setting in Japan. The pharmacokinetic-pharmacodynamic profile of dosing regimens tested in this study will assist in selecting the appropriate meropenem regimens for patients receiving CVVHD.

Correlations between extent of X-ray infiltration and levels of serum C-reactive protein in adult non-severe community-acquired pneumonia.

Pneumonia cases can vary in both severity and chest X-ray findings. Elevated C-reactive protein (CRP) levels may be an indicator of disease severity. We retrospectively evaluated factors correlated with the extent of chest X-ray infiltration both in community-acquired pneumonia (CAP) and a subgroup of cases with pneumococcal pneumonia. In a clinical study that evaluated the efficacy of sitafloxacin, 137 patients with CAP had been previously enrolled. In our study, 75 patients with pneumococcal pneumonia were identified among these 137 CAP patients. The extent of chest X-ray infiltration was scored and correlations with age, sex, body temperature, white blood cell (WBC) count, and CRP levels were analyzed using multivariate analysis with logistic regression. Significant correlations were observed between the extent of chest X-ray infiltration and CRP levels in both CAP and pneumococcal pneumonia. Our data indicates that CRP is a valuable and informative resource that could reflect the severity of pneumonia in cases of both CAP and pneumococcal pneumonia.