Risk factors and treatment strategies for cholecystitis after metallic stent placement for malignant biliary obstruction: a multicenter retrospective study.

BACKGROUND AND AIMS: Cholecystitis can occur after self-expandable metallic stent (SEMS) placement for malignant biliary obstruction (MBO), but the best treatment option for cholecystitis has not been determined. Here, we aimed to identify the risk factors of cholecystitis after SEMS placement and determine the best treatment option. METHODS: Incidence, treatments, and predictive factors of cholecystitis were retrospectively evaluated in 1084 patients with distal MBO (DMBO) and 353 patients with hilar MBO (HMBO) who underwent SEMS placement at 12 institutions from January 2012 to March 2021. RESULTS: Cholecystitis occurred in 7.5% of patients with DMBO and 5.9% of patients with HMBO. The recurrence rate was significantly lower (P = .043) and the recurrence-free period significantly longer (P = .039) in endoscopic procedures than in percutaneous procedures for cholecystitis treatment. EUS-guided gallbladder drainage (EUS-GBD) was better in terms of technical success, procedure time, and recurrence-free period than endoscopic transpapillary gallbladder drainage. Obstruction across the cystic duct orifice by tumor (P = .015) and by stent (P = .037) were independent risk factors for cholecystitis in DMBO. Cases with multiple SEMS placements (odds ratio [OR], 11; 95% confidence interval [CI], 0.68-190; P = .091) and with gallbladder stones (OR, 2.3; 95% CI ,0.92-5.6; P = .075) had a higher risk for cholecystitis in HMBO. CONCLUSIONS: The incidences of cholecystitis after SEMS placement for DMBO and HMBO were similar. EUS-GBD is the optimal treatment option for patients with cholecystitis after SEMS placement for MBO.

Involvement of gap junctions in the increased contraction of bovine oviducts at pre-ovulation observed in vitro.

In brief: Spontaneous contraction of oviductal smooth muscle is essential for gamete transport to the fertilization site in mammals. This study sheds light on the mechanism of elevated contraction amplitude in the bovine oviductal isthmus just before ovulation. Abstract: Rhythmic contraction of the oviducts is essential for transporting gametes and embryos at peri-ovulation; however, its regulatory mechanism during the estrous cycle is unclear. Meanwhile, it is reported that ion currents regulate muscle contraction. Our study aimed to clarify the involvement of ion channels and gap junctions in regulating oviductal motility during the estrous cycle in cattle. The isthmic sections of bovine oviducts collected just after ovulation (0-4 days after ovulation), at the mid-late luteal stage (10-17 days), and at the follicular stage (1-3 days before ovulation) were used in the experiments. The frequency and amplitude of contraction of the oviductal strips in the longitudinal direction were examined using the Magnus system. The frequency was not different among the estrous stages. Conversely, the amplitude was significantly higher at the follicular stage. The blockers of voltage-dependent calcium channels, both IP3 receptor and ryanodine receptors, chloride channel, and gap junction reduced the amplitude. Additionally, mRNA and protein expression of GJA1, a component of the gap junction, in the smooth muscle tissues of the oviductal isthmus were significantly higher in the follicular stage. In addition, estradiol-17ß (E2; 1.0 ng/mL) significantly increased GJA1 mRNA expression in cultured smooth muscle tissues after 24 h and GJA1 protein expression in cultured smooth muscle cells after 48 h. These results suggest that local levels of E2 in the oviductal isthmus ipsilateral to an ovary with a dominant follicle support the increased contraction amplitude of bovine ipsilateral oviducts by elevating the gap junction expression.

Cysts or necrotic components in pancreatic ductal adenocarcinoma is associated with the risk of EUS-FNA/B complications including needle tract seeding.

BACKGROUND: EUS-FNA/B for pancreatic ductal adenocarcinoma (PDAC) is generally considered to be safe; however, while the incidence is low, there are occurrences of complications. Among these complications, there are serious ones like needle tract seeding (NTS), and it is not known than which types of tumors have the risks of EUS-FNA/B complications. This study aimed to evaluate the risk of EUS-FNA/B complications in patients with PDAC, focusing on morphological features. METHODS: Overall, 442 patients who underwent EUS-FNA/B for solid pancreatic masses between January 2018 and May 2022 in four institutions were retrospectively surveyed. Finally, 361 patients histopathologically diagnosed with PDAC were analyzed. Among these patients, 79 tumors with cysts or necrotic components were compared with 282 tumors without cysts or necrotic components. The incidence and risk of EUS-FNA/B complications including NTS were evaluated. RESULTS: There were 9 (2.4 %) of total EUS-FNA/B complications and 3 (0.8 %) of NTS. The incidence of total complication rate and NTS in tumors with cysts or necrotic components were significantly higher than in those without cysts or necrotic components (total complication 6.3 % vs. 1.4 %, p = 0.026, NTS 3.7 % vs. 0 %, p = 0.01). The transgastric route of puncture (OR: 93.3, 95 % CI: 3.81-2284.23) and the existence of cysts or necrotic components (OR: 7.3, 95 % CI: 1.47-36.19) were risk factors for EUS-FNA/B complications identified by the multivariate analysis. CONCLUSIONS: We should pay attention to the risks of EUS-FNA/B complications, including NTS, when the tumor has cysts or necrotic components.

The efficacy of non-anesthesiologist-administered propofol sedation with a target-controlled infusion system during double-balloon endoscopic retrograde cholangiopancreatography.

BACKGROUND: The sedation method used during double-balloon endoscopic retrograde cholangiopancreatography (DB-ERCP) differs among countries and/or facilities, and there is no established method. This study aimed to evaluate the efficacy of non-anesthesiologist-administered propofol (NAAP) sedation using a target-controlled infusion (TCI) system during DB-ERCP. METHODS: This retrospective study was conducted between May 2017 and December 2020 at an academic center. One hundred and fifty-six consecutive patients who underwent DB-ERCP were sedated by gastroenterologists using diazepam (n = 77) or propofol with a TCI system (n = 79), depending on the period. The primary endpoint was a comparison of poor sedation rates between the two groups. Poor sedation was defined as a condition requiring the use of other sedative agents or discontinuation of the procedure. Secondary endpoints were sedation-related adverse events and risk factors for poor sedation. RESULTS: Poor sedation occurred significantly more often in the diazepam sedation group (diazepam sedation, n = 12 [16%] vs. propofol sedation, n = 1 [1%]; P = 0.001). Vigorous body movements (3 or 4) (diazepam sedation, n = 40 [52%] vs. propofol sedation, n = 28 [35%]; P = 0.038) and hypoxemia (< 85%) (diazepam sedation, n = 7 [9%] vs. propofol sedation, n = 1 [1%]; P = 0.027) occurred significantly more often in the diazepam sedation group. In the multivariate analysis, age < 70 years old (OR, 10.26; 95% CI, 1.57-66.98; P = 0.015), BMI ≥ 25 kg/m2 (OR, 11.96; 95% CI, 1.67-85.69; P = 0.014), and propofol sedation (OR, 0.06; 95% CI, 0.01-0.58; P = 0.015) were associated factors for poor sedation. CONCLUSIONS: NAAP sedation with the TCI system during DB-ERCP was safer and more effective than diazepam sedation.

Application of convolutional neural networks for evaluating the depth of invasion of early gastric cancer based on endoscopic images.

BACKGROUND AND AIM: Recently, artificial intelligence (AI) has been used in endoscopic examination and is expected to help in endoscopic diagnosis. We evaluated the feasibility of AI using convolutional neural network (CNN) systems for evaluating the depth of invasion of early gastric cancer (EGC), based on endoscopic images. METHODS: This study used a deep CNN model, ResNet152. From patients who underwent treatment for EGC at our hospital between January 2012 and December 2016, we selected 100 consecutive patients with mucosal (M) cancers and 100 consecutive patients with cancers invading the submucosa (SM cancers). A total of 3508 non-magnifying endoscopic images of EGCs, including white-light imaging, linked color imaging, blue laser imaging-bright, and indigo-carmine dye contrast imaging, were included in this study. A total of 2288 images from 132 patients served as the development dataset, and 1220 images from 68 patients served as the testing dataset. Invasion depth was evaluated for each image and lesion. The majority vote was applied to lesion-based evaluation. RESULTS: The sensitivity, specificity, and accuracy for diagnosing M cancer were 84.9% (95% confidence interval [CI] 82.3%-87.5%), 70.7% (95% CI 66.8%-74.6%), and 78.9% (95% CI 76.6%-81.2%), respectively, for image-based evaluation, and 85.3% (95% CI 73.4%-97.2%), 82.4% (95% CI 69.5%-95.2%), and 83.8% (95% CI 75.1%-92.6%), respectively, for lesion-based evaluation. CONCLUSIONS: The application of AI using CNN to evaluate the depth of invasion of EGCs based on endoscopic images is feasible, and it is worth investing more effort to put this new technology into practical use.

Double guidewire technique stabilization procedure for endoscopic ultrasound-guided hepaticogastrostomy involving modifying the guidewire angle at the insertion site.

BACKGROUND AND AIMS: Endoscopic ultrasonography-guided hepaticogastrostomy (EUS-HGS) is often performed using a single guidewire (SGW), but the efficacy of the double guidewire (DGW) technique during endoscopic ultrasonography-guided biliary drainage has been reported. We evaluated the efficacy of the DGW technique for EUS-HGS, focusing on the guidewire angle at the insertion site. METHODS: This retrospective cohort study included consecutive patients who underwent EUS-HGS between April 2012 and March 2021. We measured the guidewire angle at the insertion site using still fluoroscopic imaging. We compared the clinical outcomes of EUS-HGS with the DGW and SGW techniques. The factors associated with successful cannula insertion, need for additional fistula dilation and adverse event rate were assessed by a logistic regression multivariable analysis. RESULTS: The DGW group showed higher technical (p = 0.020) and clinical success rates (p = 0.016) than the SGW group, which showed more adverse events (p = 0.017) than the DGW group. Successful cannula insertion was associated with a guidewire angle > 137° and an uneven double-lumen cannula. The DGW technique made the guidewire angle obtuse at the insertion site (p < 0.0001). A guidewire angle ≤ 137° (OR, 35.6; 95% CI, 1.70-744; p = 0.0045) and intrahepatic bile duct diameter of the puncture site ≤ 3.0 mm (OR, 14.4; 95% CI, 1.37-152; p = 0.0056) were risk factors for needing additional fistula dilation in a multivariate analysis, and additional dilation was a significant predictive factor for adverse events (OR, 8.3; 95% CI, 0.9-77; p = 0.026). CONCLUSIONS: The DGW technique can modify the guidewire angle at the insertion site and facilitate stent deployment with few adverse events.

Propofol sedation with a target-controlled infusion pump in elderly patients undergoing ERCP.

BACKGROUND AND AIMS: Advanced age is an important risk factor for adverse events (AEs) during propofol sedation for endoscopic procedures. This study aimed to evaluate the safety and efficacy of nonanesthesiologist-administered propofol (NAAP) sedation with a target-controlled infusion (TCI) system in elderly patients during ERCP. METHODS: This study retrospectively analyzed 482 patients who underwent ERCP under propofol sedation with a TCI system at Iwakuni Medical Center between January 2014 and October 2016. Patients were divided into 3 groups according to their age: group A, <70 years (n = 130); group B, ≥70 and <85 years (n = 224); and group C, ≥85 years (n = 125). We compared the propofol dose and AEs during ERCP. RESULTS: The median total infusion dose and minimum and maximum target blood concentrations of propofol were 336 mg, 2.2 µg/mL, and 2.2 µg/mL in group A; 184 mg, 1.0 µg/mL, and 1.4 µg/mL in group B; and 99 mg, .6 µg/mL, and 1.0 µg/mL in group C, respectively, with older groups requiring a lower dose (P < .0001). Hypotension was observed in 23 patients (4.8%), with no significant difference between groups (group A, 2.3%; group B, 6.3%; group C, 4.8%; P = .24). Hypoxemia was observed in 16 patients (3.3%), with no significant difference between groups (group A, 3.1%; group B, 4.9%; group C, .8%; P = .17). All AEs were immediately resolved, and no procedures were aborted. CONCLUSIONS: NAAP sedation with a TCI system during ERCP may be acceptable in elderly patients with a lower dose of propofol than that used in younger patients.

Impact of cognitive function on oral perception in independently living older people.

OBJECTIVES: Oral tactile perception is important for better mastication, appetite, and enjoyment of food. However, previous investigations have not utilized comprehensible variables thought to have negative effect on oral perception, including aging, denture wearing, and cognitive function. The aim of this study was to elucidate the impact of cognitive function on oral perception in independently living older individuals. MATERIALS AND METHODS: The study sample was comprised of 987 participants (466 males, 521 females; age 69-71 years). Oral examinations, assessments of cognitive function in preclinical level by Montreal Cognitive Assessment (MoCA)-J, and determination of oral stereognostic ability as an indicator of oral perception were performed. Related variables were selected by univariate analyses; then, multivariate logistic regression model analysis was conducted. RESULTS: Univariate analyses revealed that number of teeth, removable dentures usage, and cognitive function respectively had a significant relationship with stereognostic score. Next, the subjects were classified into good and poor perception groups (lowest 17.4%) according to oral stereognostic ability. Logistic regression analysis revealed that lower cognitive function was significantly associated with poor oral perception (OR = 0.934, p = 0.017) after controlling for other variables. CONCLUSIONS: Cognitive decline even in preclinical stage was associated with reduced oral perception after controlling for gender, tooth number and denture use in independent living older people. CLINICAL RELEVANCE: This study suggested that preclinical level of change in cognitive function affected oral perception. Dental practitioners and caregivers may need to pay attention to reduced oral perception among older people even if they do not have trouble in daily life.

Streptococcus pyogenes Endopeptidase O Contributes to Evasion from Complement-mediated Bacteriolysis via Binding to Human Complement Factor C1q.

Streptococcus pyogenes secretes various virulence factors for evasion from complement-mediated bacteriolysis. However, full understanding of the molecules possessed by this organism that interact with complement C1q, an initiator of the classical complement pathway, remains elusive. In this study, we identified an endopeptidase of S. pyogenes, PepO, as an interacting molecule, and investigated its effects on complement immunity and pathogenesis. Enzyme-linked immunosorbent assay and surface plasmon resonance analysis findings revealed that S. pyogenes recombinant PepO bound to human C1q in a concentration-dependent manner under physiological conditions. Sites of inflammation are known to have decreased pH levels, thus the effects of PepO on bacterial evasion from complement immunity was analyzed in a low pH condition. Notably, under low pH conditions, PepO exhibited a higher affinity for C1q as compared with IgG, and PepO inhibited the binding of IgG to C1q. In addition, pepO deletion rendered S. pyogenes more susceptible to the bacteriocidal activity of human serum. Also, observations of the morphological features of the pepO mutant strain (ΔpepO) showed damaged irregular surfaces as compared with the wild-type strain (WT). WT-infected tissues exhibited greater severity and lower complement activity as compared with those infected by ΔpepO in a mouse skin infection model. Furthermore, WT infection resulted in a larger accumulation of C1q than that with ΔpepO. Our results suggest that interaction of S. pyogenes PepO with C1q interferes with the complement pathway, which enables S. pyogenes to evade complement-mediated bacteriolysis under acidic conditions, such as seen in inflammatory sites.

Association of handgrip strength with various oral functions in 82- to 84-year-old community-dwelling Japanese.

OBJECTIVE: The purpose of this study was to elucidate the associations between muscle strength and several oral functions in a large cohort of community-dwelling, 82- to 84-year-old community-dwelling Japanese people. BACKGROUND DATA DISCUSSING THE PRESENT STATUS OF THE FIELD: Several studies have examined the relationships between physical performance and oral functions. However, no studies have investigated the associations of muscle strength with various objectively evaluated oral functional parameters in a large cohort of very old adults. MATERIALS AND METHODS: This study included 809 community-dwelling Japanese people (407 men and 402 women) aged 82-84 years. The oral functions examined were the maximal occlusal force, masticatory performance, stimulated salivary flow rate, repetitive saliva-swallowing test (RSST) score, tongue pressure and mouth-opening distance. Handgrip strength was measured, and its correlations with oral functions were assessed. Multiple linear and logistic regression analyses were performed to investigate the relationships between oral functions and handgrip strength. RESULTS: Multivariate analysis revealed that handgrip strength was correlated with not only the maximal occlusal force, masticatory performance and tongue pressure but also the RSST score and mouth-opening distance after adjustment for sex, number of teeth, use of removable denture, periodontal condition, instrumental activities of daily living, body mass index. When we examine the elderly people whose handgrip strength is declining, we should predict that their various oral functions may be declining. CONCLUSION: Handgrip strength was related to various oral functions after adjustment for the number of teeth in this population of community-dwelling 82- to 84-year-old Japanese.

Increased neutrophil extracellular trap-mediated Staphylococcus aureus clearance through inhibition of nuclease activity by clindamycin and immunoglobulin.

The Gram-positive human pathogen Staphylococcus aureus causes a variety of human diseases such as skin infections, pneumonia, and endocarditis. The micrococcal nuclease Nuc1 is one of the major S. aureus virulence factors and allows the bacterium to avoid neutrophil extracellular trap (NET)-mediated killing. We found that addition of the protein synthesis inhibitor clindamycin to S. aureus LAC cultures decreased nuc1 transcription and subsequently blunted nuclease activity in a molecular beacon-based fluorescence assay. We also observed reduced NET degradation through Nuc1 inhibition translating into increased NET-mediated clearance. Similarly, pooled human immunoglobulin specifically inhibited nuclease activity in a concentration-dependent manner. Inhibition of nuclease activity by clindamycin and immunoglobulin enhanced S. aureus clearance and should be considered in the treatment of S. aureus infections.

Cysteine proteinase from Streptococcus pyogenes enables evasion of innate immunity via degradation of complement factors.

Streptococcus pyogenes is an important human pathogen that causes invasive diseases such as necrotizing fasciitis, sepsis, and streptococcal toxic shock syndrome. We investigated the function of a major cysteine protease from S. pyogenes that affects the amount of C1-esterase inhibitor (C1-INH) and other complement factors and aimed to elucidate the mechanism involved in occurrence of streptococcal toxic shock syndrome from the aspect of the complement system. First, we revealed that culture supernatant of a given S. pyogenes strain and recombinant SpeB degraded the C1-INH. Then, we determined the N-terminal sequence of the C1-INH fragment degraded by recombinant SpeB. Interestingly, the region containing one of the identified cleavage sites is not present in patients with C1-INH deficiency. Scanning electron microscopy of the speB mutant incubated in human serum showed the abnormal superficial architecture and irregular oval structure. Furthermore, unlike the wild-type strain, that mutant strain showed lower survival capacity than normal as compared with heat-inactivated serum, whereas it had a significantly higher survival rate in serum without the C1-INH than in normal serum. Also, SpeB degraded multiple complement factors and the membrane attack complex. Flow cytometric analyses revealed deposition of C9, one of the components of membrane the attack complex, in greater amounts on the surface of the speB mutant, whereas lower amounts of C9 were bound to the wild-type strain surface. These results suggest that SpeB can interrupt the human complement system via degrading the C1-INH, thus enabling S. pyogenes to evade eradication in a hostile environment.

Investigation of oral opportunistic pathogens in independent living elderly Japanese.

OBJECTIVE: Pneumonia is reported to be associated with high morbidity in elderly and compromised individuals, with poor oral health demonstrated to be a significant risk factor for pneumonia. Several opportunistic pathogens, such as Streptococcus pneumoniae, Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus, have been detected in patients with pneumonia. We investigated the prevalence of opportunistic pathogens in the oral cavity of healthy independent living Japanese elderly subjects and analysed factors related to harbouring those pathogens. MATERIALS AND METHODS: We studied 265 subjects, each of whom received a dental examination, during which specimens were collected with a tongue swab and examined for the presence of 10 oral opportunistic pathogens using single or multiple selective media. Furthermore, the presence of occult blood in saliva was examined using test paper strips. RESULTS: Oral opportunistic pathogens were detected in 13.6% of the subjects. Those positive for occult blood in saliva had a significantly higher rate of harbouring the pathogens (p < 0.05). In addition, age was a significant factor for the presence of pathogenic microbes in the oral cavity (p = 0.033). CONCLUSION: Positive findings of occult blood in saliva and older age are suggested to be significant factors for harbouring opportunistic pathogens in the oral cavity.

Clinically acceptable restorations may be a hotbed for cariogenic microbes.

OBJECTIVE: The aim of this study was to investigate the cross-sectional association of dental restorations with salivary cariogenic pathogens among the elderly to establish effective parameters of caries risk for this population. MATERIALS AND METHODS: Stimulated whole saliva was collected from 289 community-dwelling older adults (66.2 ± 3.9 years old) who had 20 or more teeth. Salivary levels of three cariogenic bacteria (Streptococcus mutans, Streptococcus sobrinus and lactobacilli) were estimated using quantitative polymerase chain reaction (real-time PCR) method. RESULTS: The mean number of residual teeth was 26.4, and restored teeth with crowns, inlays and composite resin were 7.35, 3.88 and 0.68, respectively. The number of crowns correlated positively with salivary S. mutans, S. sobrinus and lactobacilli. Multiple linear regression analyses showed that the number of restored teeth with crowns was independently associated with salivary S. mutans, S. sobrinus and lactobacilli after controlling for age, gender, number of residual teeth and salivary flow rate. Salivary flow rate was independently associated with salivary S. mutans and lactobacilli. CONCLUSION: The number of crowns had an association with salivary levels of cariogenic bacteria, suggesting that this parameter may be a caries risk indicator for the elderly population.

Endoscopic removal of proximally migrated stents using a double-balloon enteroscope in patients with bowel reconstruction (with video).

Endoscopic migrated stent removal using a balloon-assisted enteroscope is technically difficult in patients with bowel reconstruction. We report the treatment outcomes and endoscopic removal methods for migrated stents using a double-balloon enteroscope (DBE). We retrospectively studied 12 patients with stent migration into the main pancreatic duct (MPD) or bile duct who underwent bowel reconstruction between January 2012 and June 2020. The successful removal rates in the MPD (n = 3) and the bile duct (n = 9) were 66.7% (2/3) and 88.9% (8/9), respectively. The removal techniques included the indirect method (n = 3), the direct method (n = 4), and a combination of indirect and direct methods (n = 3). The removal devices included an extraction balloon catheter (n = 7), basket catheter (n = 5), biopsy forceps (n = 3), and snare (n = 2). Stent removal using a DBE was feasible and useful as the first treatment for patients with bowel reconstruction. The choice of the direct and/or indirect method according to the situation of the migrated stent is important.

Bilateral verses bilateral with tri-segmental endoscopic drainage using metal stents for high-grade malignant hilar biliary obstructions: A multicenter, randomized controlled trial: BRAVE study (BRAVE study).

INTRODUCTION: Bilateral endoscopic drainage with self-expanding metallic stent (SEMS) can be used to manage hilar malignant biliary obstruction (HMBO) more effectively in comparison to unilateral drainage. An increased drainage area is predicted to prolong stent patency and patient survival. However, few reports have described the utility of trisegmental drainage and the benefits of using trisegmental drainage remain unknown. Thus, we launched a randomized clinical trial (RCT) to compare the clinical outcomes between bilateral and trisegmental drainage using SEMSs in patients with high-grade HMBO. METHODS AND ANALYSIS: This study was conducted as a multicenter randomized control trial (RCT) in 8 high-volume medical centers in Japan, and will prove the non-inferiority of bilateral drainage to trisegmental drainage. Patients with unresectable HMBO with Bismuth type IIIa or IV who pass the inclusion and exclusion criteria will be randomized to receive bilateral or trisegmental drainage at a 1:1 ratio. At each center, the on-site study investigators will obtain informed consent from the candidates, and will use an electronic data capture system (REDCap) to input necessary information, and register candidates with the registration secretariat. The primary endpoint is the rate of non-recurrent biliary obstruction (RBO) at 180 days after SEMSs placement. A -10% non-inferiority margin is assumed in the statistical analysis of the primary endpoint. Secondary endpoints include the rate of technical and clinical success, time to recurrent biliary obstruction (TRBO), causes of RBO, procedure-related adverse events (AEs), procedure time, TRBO with or without endoscopic sphincterotomy, overall survival, and the technical and clinical success rates at reintervention. DISCUSSION: If the non-inferiority of bilateral drainage is demonstrated, it is predicted that the procedure time will be shortened and the medical cost will be reduced, which will be beneficial to the patient and the medical economy. TRIAL REGISTRATION: Registered in Japan Registry of Clinical Trial-Registration (trial number. jRCTs062220038). This version number 1. Protocol dated Jun 23, 2022.

Biofilm formation or internalization into epithelial cells enable Streptococcus pyogenes to evade antibiotic eradication in patients with pharyngitis.

Streptococcus pyogenes is the bacterium most frequently isolated from patients with pharyngitis. Although various antibiotics including penicillin are effective, antibiotic treatment failure in cases of streptococcal pharyngitis have been reported. Herein, we investigated mechanisms associated with recurrent streptococcal pharyngitis. Clinically isolated S. pyogenes strains showed serotype-specific features, with emm12 strains most frequently detected and emm6 strains more likely to produce biofilm. The architectures of formed biofilms were observed using a fluorescence microscope with Live/Dead staining. Furthermore, various cationic antimicrobial peptides were tested to evaluate their inhibitory activities toward biofilms formed by S. pyogenes. After treatments with high concentrations of antibiotics, S. pyogenes survived in biofilm even when dead bacterial cells covered the surface. Other findings demonstrated that some antimicrobial peptides have inhibitory effects on forming and formed biofilm. Moreover, emm4, emm6, and emm75 strains showed significantly higher levels of invasion capacity into Detroit 562 cells than strains with other genotypes. Additionally, more than half of the strains temporarily escaped killing by penicillin alone by internalization into epithelial cells, even when the antibiotic concentration used was greater than the 10-fold minimum inhibitory concentration (MIC) for planktonic S. pyogenes. Also, combined administrations of multiple antibiotics were more effective to eradicate strains more likely to be internalized. Finally, flow cytometric analyses demonstrated that emm12 strains with higher invasive capabilities expressed PrtF1 protein on the bacterial surface. These findings suggest that S. pyogenes isolated from patients with recurrent streptococcal pharyngitis have emm type-specific features that allow escape from eradication by antibiotics.

Subjective values of different age groups in Japan regarding treatment for missing molars.

OBJECTIVE: To determine how patients and dentists in Japan value the outcomes of different treatment options for missing molars. MATERIALS AND METHODS: Elderly removable-denture wearers and dentate persons (senior group), preclinical dental students (young group), and prosthodontists were presented with five possible treatment options for missing lower bilateral first and second molars. The participants indicated on a visual analogue scale how they would value the treatment (utility value: UV), if they had received each of the treatments. Two-way repeated measures anova was used for statistical analyses. RESULTS: The UV for the shortened dental arch (SDA) without replacement was the lowest in every group. The young group rated the value of cantilever fixed partial dentures (FPD) and implants significantly higher than removable partial dentures (RPD), while the senior group rated the value of FPD and RPD significantly higher than implants. Those having experience with removable dentures were likely to place a higher value on the acrylic RPD. The prosthodontists rated the value of implants significantly higher than any other options. CONCLUSIONS: The participants in every group placed the lowest value on the outcome from the SDA in Japan. The denture wearers preferred the RPD, while prosthodontists preferred implants.

Nrc of Streptococcus pneumoniae suppresses capsule expression and enhances anti-phagocytosis.

Streptococcus pneumoniae is a major pathogen of community-acquired pneumonia and one of its major virulence factors is pneumolysin, which functions as a cholesterol-dependent cytolytic pore-forming toxin. In this study, we identified the ply-like gene spd0729 in a BLAST search. Unexpectedly, hemolytic and cytotoxic assays showed no significant differences between a Deltaspd0729 mutant strain and the wild-type strain, whereas the mutant strain exhibited weaker anti-phagocytic activity in human peripheral blood. In addition, real-time RT-PCR analysis revealed that four capsular biosynthesis genes in the mutant strain had expressions 7- to 432-fold greater than those of the wild type, while an enzyme-linked immunoassay showed a mean 3-fold greater amount of total capsular polysaccharide in the mutant strain. These results suggest that Spd0729 is not a cytolysin, though it plays crucial roles in anti-phagocytosis and regulation of capsule expression. Thus, we named Spd0729 as a negative regulator of capsular polysaccharide synthesis (Nrc).

Composition of salivary microbiota in elderly subjects.

Frailty is gaining attention worldwide with the aging of society. Despite the potential lethality and multiple signs and symptoms in affected individuals, preclinical detection of early manifestations leading to frailty syndrome have not been established. We speculated that the composition of the oral microbiota is associated with general frailty, as well as a relationship between gut microbiota and general health condition. In the present study, we investigated the salivary microbiota composition in samples from healthy and frail elderly individuals using 16S rRNA sequencing analysis for characterization. We found a significant difference in diversity between elderly individuals living in a nursing home (EN) and healthy control (HC) subjects, as well as in the microbiota composition at the phyla level. A supervised orthogonal partial least squared discriminant analysis (OPLS-DA) revealed a significant difference in clear classification trend between the EN and HC groups, with all observations falling within the Hotellings T2 (0.95) ellipse, with model fitness parameters of R 2(cum) = 0.937 and Q 2(cum) = 0.888, respectively. In addition, the score plots by unsupervised principal component analysis (PCA) showed a clear classification trend in both groups. Our findings suggest that general frailty is associated with oral microbiota composition and formation.