Total knee arthroplasty and periprosthetic distal femoral fracture: looking beyond the osteoporosis to previous osteoporotic fracture.

Osteoporosis increases the risk of periprosthetic distal femoral fractures after TKA, especially in patients with a history of osteoporotic fractures. Therefore, careful assessment and proper treatment of osteoporosis need and the importance of taking osteoporotic medication needs to be recognized by the patients following primary TKA. PURPOSE: Osteoporosis is a risk factor for fractures, including those of the hip, vertebrae, and distal radius; however, the association between osteoporosis and periprosthetic fractures after total knee arthroplasty (TKA) has not been much investigated. Therefore, we aimed to investigate the association of the presence of systemic osteoporosis with periprosthetic fractures after TKA. METHODS: This study included 34 patients with periprosthetic fractures following primary TKA and 106 controls matched for age and sex. Bone mineral density was evaluated at the femoral neck, total hip, and lumbar spine using dual X-ray absorptiometry. Medical records were reviewed for age; sex; body mass index; smoking; rheumatoid arthritis, endocrine diseases, and cardiovascular diseases; history of glucocorticoid use; medication for osteoporosis; and history of previous osteoporotic fracture. In addition, anterior femoral notching after TKA was evaluated. Univariable and multivariable logistic regression analysis were used to determine factors associated with periprosthetic fracture. RESULTS: The prevalence of osteoporosis in the fracture group was higher than that in the control group (61.8% vs. 40.6%, p=0.045). The rate of medication for osteoporosis was significantly low in the fracture group (47.6 % vs 76.7%, p=0.026). History of previous osteoporotic fracture (odds ratio [OR], 9.1; p=0.015) and osteoporosis (OR, 3.6; p=0.013) were significant risk factors for periprosthetic fractures after TKA. Medication for osteoporosis could decrease the risk of periprosthetic fracture (OR 0.3; p=0.020). CONCLUSION: Osteoporosis is a major risk factor for periprosthetic distal femoral fractures after TKA. Therefore, careful assessment and proper treatment of osteoporosis need and the importance of taking osteoporotic medication needs to be recognized to the patients following primary TKA, especially in patients with a history of osteoporotic fracture. LEVEL OF EVIDENCE: Prognostic study, level III.

ESMO Expert Consensus Statements on Cancer Survivorship: promoting high-quality survivorship care and research in Europe.

BACKGROUND: The increased number of cancer survivors and the recognition of physical and psychosocial challenges, present from cancer diagnosis through active treatment and beyond, led to the discipline of cancer survivorship. DESIGN AND METHODS: Herein, we reflected on the different components of survivorship care, existing models and priorities, in order to facilitate the promotion of high-quality European survivorship care and research. RESULTS: We identified five main components of survivorship care: (i) physical effects of cancer and chronic medical conditions; (ii) psychological effects of cancer; (iii) social, work and financial effects of cancer; (iv) surveillance for recurrences and second cancers; and (v) cancer prevention and overall health and well-being promotion. Survivorship care can be delivered by structured care models including but not limited to shared models integrating primary care and oncology services. The choice of the care model to be implemented has to be adapted to local realities. High-quality care should be expedited by the generation of: (i) focused and shared European recommendations, (ii) creation of tools to facilitate implementation of coordinated care and (iii) survivorship educational programs for health care teams and patients. The research agenda should be defined with the participation of health care providers, researchers, policy makers, patients and caregivers. The following patient-centered survivorship research areas were highlighted: (i) generation of a big data platform to collect long-term real-world data in survivors and healthy controls to (a) understand the resources, needs and preferences of patients with cancer, and (b) understand biological determinants of survivorship issues, and (ii) develop innovative effective interventions focused on the main components of survivorship care. CONCLUSIONS: The European Society for Medical Oncology (ESMO) can actively contribute in the efforts of the oncology community toward (a) promoting the development of high-quality survivorship care programs, (b) providing educational material and (c) aiding groundbreaking research by reflecting on priorities and by supporting research networking.

Betulinic acid inhibits high-fat diet-induced obesity and improves energy balance by activating AMPK.

BACKGROUND AND AIM: Metabolic syndromes are prevalent worldwide and result in various complications including obesity, cardiovascular disease and type II diabetes. Betulinic acid (BA) is a naturally occurring triterpenoid that has anti-inflammatory properties. We hypothesized that treatment with BA may result in decreased body weight gain, adiposity and hepatic steatosis in a diet-induced mouse model of obesity. METHODS AND RESULTS: Mice fed a high-fat diet and treated with BA showed less weight gain and tissue adiposity without any change in calorie intake. Gene expression profiling of mouse tissues and cell lines revealed that BA treatment increased expression of lipid oxidative genes and decreased that of lipogenesis-related genes. This modulation was mediated by increased AMP-activated protein kinase (AMPK) phosphorylation, which facilitates energy expenditure, lipid oxidation and thermogenic capacity and exerts protective effects against obesity and nonalcoholic fatty liver disease. Overall, BA markedly inhibited the development of obesity and nonalcoholic fatty liver disease in mice fed a high-fat diet, and AMPK activation in various tissues and enhanced thermogenesis are two possible mechanisms underlying the antiobesity and antisteatogenic effects of BA. CONCLUSIONS: The current findings suggest that treatment with BA is a potential dietary strategy for preventing obesity and nonalcoholic fatty liver disease.

Grading system for migrated lumbar disc herniation on sagittal magnetic resonance imaging: an agreement study.

PURPOSE: Migrated lumbar disc herniations (LDHs) in the sagittal plane are common. Disc migration grading can be applied as a useful measurement tool in the diagnosis, treatment, and outcome evaluation of migrated LDH. No study has evaluated the reliability of migrated LDH grading. We evaluated the reliability and functionality of the current magnetic resonance imaging (MRI) grading system for migrated LDH. METHODS: We assessed a six-level grading system developed based on sagittal MRI and graded according to the direction (rostral and caudal) and degree (low, high, and very high) of disc migration. One-hundred and one migrated LDHs treated with minimally invasive endoscopic discectomy were analyzed independently by two experienced radiologists. Intraobserver and interobserver agreements were assessed by kappa statistics. RESULTS: The most common migrated LDH grade was grade 4 (30.94%; caudal, low-grade migration). Rostral and caudal migrations were more common in the upper and lower lumbar levels, respectively. Interobserver agreement in the grading of migrated LDH was good at both the first (kappa = 0.737) and second assessment (kappa = 0.657). The intraobserver agreement for reader 1 was very good (kappa = 0.827) and for reader 2 was good (kappa = 0.620). CONCLUSIONS: The current grading system for migrated LDH was found to be reliable and functional with good interobserver and intraobserver agreement. It may be useful in the interpretation of disc migration patterns and outcomes of various minimally invasive surgical procedures.

Quantum Transition Properties of Quasi Two Dimensional and Electron-Phonon Interacting System in ZnO and CdS.

We investigated theoretically the quantum optical transition properties of quasi 2-Dimensional Landau splitting system, in ZnO and CdS. We apply the Quantum Transport theory (QTR) to the system in the confinement of electrons by square well confinement potential. We use the projected Liouville equation method with Equilibrium Average Projection Scheme (EAPS). In order to analyze the quantum transition, we compare the temperature and the magnetic field dependencies of the QTLW and the QTLS on two transition processes, namely, the phonon emission transition process and the phonon absorption transition process.

Non-Brownian diffusion in lipid membranes: Experiments and simulations.

The dynamics of constituents and the surface response of cellular membranes-also in connection to the binding of various particles and macromolecules to the membrane-are still a matter of controversy in the membrane biophysics community, particularly with respect to crowded membranes of living biological cells. We here put into perspective recent single particle tracking experiments in the plasma membranes of living cells and supercomputing studies of lipid bilayer model membranes with and without protein crowding. Special emphasis is put on the observation of anomalous, non-Brownian diffusion of both lipid molecules and proteins embedded in the lipid bilayer. While single component, pure lipid bilayers in simulations exhibit only transient anomalous diffusion of lipid molecules on nanosecond time scales, the persistence of anomalous diffusion becomes significantly longer ranged on the addition of disorder-through the addition of cholesterol or proteins-and on passing of the membrane lipids to the gel phase. Concurrently, experiments demonstrate the anomalous diffusion of membrane embedded proteins up to macroscopic time scales in the minute time range. Particular emphasis will be put on the physical character of the anomalous diffusion, in particular, the occurrence of ageing observed in the experiments-the effective diffusivity of the measured particles is a decreasing function of time. Moreover, we present results for the time dependent local scaling exponent of the mean squared displacement of the monitored particles. Recent results finding deviations from the commonly assumed Gaussian diffusion patterns in protein crowded membranes are reported. The properties of the displacement autocorrelation function of the lipid molecules are discussed in the light of their appropriate physical anomalous diffusion models, both for non-crowded and crowded membranes. In the last part of this review we address the upcoming field of membrane distortion by elongated membrane-binding particles. We discuss how membrane compartmentalisation and the particle-membrane binding energy may impact the dynamics and response of lipid membranes. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.

Control of interior surface materials for speech privacy in high-speed train cabins.

The effect of interior materials with various absorption coefficients on speech privacy was investigated in a 1:10 scale model of one high-speed train cabin geometry. The speech transmission index (STI) and privacy distance (rP ) were measured in the train cabin to quantify speech privacy. Measurement cases were selected for the ceiling, sidewall, and front and back walls and were classified as high-, medium- and low-absorption coefficient cases. Interior materials with high absorption coefficients yielded a low rP , and the ceiling had the largest impact on both the STI and rP among the interior elements. Combinations of the three cases were measured, and the maximum reduction in rP by the absorptive surfaces was 2.4 m, which exceeds the space between two rows of chairs in the high-speed train. Additionally, the contribution of the interior elements to speech privacy was analyzed using recorded impulse responses and a multiple regression model for rP using the equivalent absorption area. The analysis confirmed that the ceiling was the most important interior element for improving speech privacy. These results can be used to find the relative decrease in rP in the acoustic design of interior materials to improve speech privacy in train cabins.

Referred symptom from myofascial pain syndrome: One of the most important causes of sensory disturbance in breast cancer patients using taxanes.

The aim of this retrospective study was to evaluate common causes of upper extremity sensory disturbance in breast cancer patients. Breast cancer patients who received surgery and taxane chemotherapy (CTx) with upper extremity sensory disturbance that began after CTx were included. With comprehensive clinical history, physical examination and electrodiagnostic results, diagnosis for each patient was made. Fifty-two patients were included: 23 (44.2%) were diagnosed with chemotherapy-induced peripheral neuropathy (CIPN), 7 (13.5%) with myofascial pain syndrome (MPS), six (11.5%) with carpal tunnel syndrome (CTS), four (7.7%) with CIPN and MPS, and three (5.8%) with CIPN and CTS. CIPN was more correlated with sensory symptoms at upper and lower extremities, a shorter time from CTx start, and adriamycin and cytoxan (AC) plus paclitaxel, than with AC plus docetaxel and fluorouracil, epirubicin and cyclophosphamide plus taxanes. MPS was correlated with longer duration of CTx and use of hormone therapy. CTS was correlated with wrist trauma history. Patients with CIPN showed similar degrees of pain even after 3 months of treatment, in comparison to the patients with MPS and CTS. When breast cancer patients complain of upper extremity sensory disturbance, various causes, especially referred symptom from MPS, should be considered for effective treatment.

Association of high-dose postoperative opioids with recurrence risk in esophageal squamous cell carcinoma: reinterpreting ERAS protocols for long-term oncologic surgery outcomes.

Esophageal squamous cell carcinoma (ESCC) is associated with a poor prognosis and high postoperative recurrence rate. Although postoperative opioid use has been associated with cancer recurrence, its relevance in ESCC has not been determined. Therefore, this study investigated whether high-dose postoperative opioid use was associated with recurrence risk in patients with ESCC. For this retrospective analysis, the medical records of patients who were diagnosed with ESCC and who underwent surgery between January 2006 and December 2010 in the National Cancer Center, Korea were evaluated. Total opioid administration over a 10-day period, from during surgery to postoperative day 9, was calculated. A cutoff value was determined using receiver operating characteristic curve analysis, and patients were classified into the high-use and low-use groups. The primary and secondary outcomes of the study were freedom from recurrence and overall survival, respectively. After propensity score matching, the effect of opioid use on freedom from recurrence and overall survival was evaluated using the Kaplan-Meier method. The final analysis set included 258 patients. The cumulative opioid dose cutoff point was 1783.5 mg of oral morphine. High-dose postoperative opioid use was a significant factor affecting recurrence (Hazard ratio [HR], 2.162; 95% confidence interval [CI], 1.583-2.954; P < 0.0001). In contrast, postoperative opioid use was not associated with death (HR, 1.274; 95% CI, 0.922-1.761; P = 0.1422). In patients with ESCC, compared with low-dose opioid use, high-dose intraoperative and postoperative opioid use was significantly associated with an increased risk of recurrence. However, opioid dosage did not affect overall survival.

Robot-assisted laparoscopic adenomyomectomy of adenomyotic nodule implanted in the uterine endometrium manifesting as endometrial cancer: a case report and literature review.

Thickened uterine endometrium with abnormal uterine bleeding highly suggests endometrial hyperplasia or endometrial carcinoma. A case of 35-year-old nulliparous woman came to our department with endometrial mass manifesting as endometrial cancer. Transrectal ultrasonography and magnetic resonance imaging (MRI) showed an 8x6 cm multicystic, ill-defined mass compacted at the uterine endometrium, the anterior wall of the uterus, and 3x3 cm heterogenous mass at the left adnexa. The edometrial mass showed multiple septations with enhancement and low-signal intensity on T2-weighted images. After endometrial biopsy was done and simple hyperplasia without atypia was observed at the histopathologic finding, the patient underwent robot-assisted laparoscopy and diagnosed as adenomyoma at the frozen pathology. After adenomyomectomy, permanent pathologic analysis revealed the same result and she recovered without any complications and responded well to gonadotropin-releasing hormone (GnRH) agonist therapy.

Activities of daily living and oral hygiene status of older Korean patients in a long-term care facility.

OBJECTIVES: This study investigated the relationship between oral hygiene conditions, activities of daily living (ADL) and cognitive ability in older Korean patients in long-term care facilities. METHODS: Ninety older persons (65+) were randomly sampled from a possible 112 residents in a single facility. They participated in a 2-month-long survey. The Korean Modified Barthel Index was used to measure the ADL, and cognitive ability was measured using the Mini-Mental State Examination, Korean version. Oral hygiene status was measured using the Simplified Oral Hygiene Index and the Tongue Coating Index (TCI). RESULTS: Older participants with complete dependence manifested significantly poorer oral hygiene (P < 0.05). Scores on the TCI were significantly higher in participants who were dentulous with partial dependence (P < 0.05). A multiple regression analysis showed that dependence and being dentulous significantly predicted poorer oral hygiene (P < 0.05). CONCLUSIONS: This study suggests that older participants with complete dependence had poor oral hygiene on tooth surfaces, while participants with partial dependence had poor tongue hygiene. In addition, dentulous older participants had poorer tongue hygiene than edentulous ones. This indicates the need to assess tooth status and provide oral care services via ADL in long-term care facilities.

Characterization and complete genome sequence analysis of two Myoviral bacteriophages infecting clinical carbapenem-resistant Acinetobacter baumannii isolates.

AIMS: The aim of this study was to characterize phenotypical properties, to analyse whole genomes of novel Acinetobacter baumannii phages infecting carbapenem-resistant Ac. baumannii (CRAB) and to evaluate their potential as antimicrobial alternatives to control Ac. baumannii in clinical settings. METHODS AND RESULTS: The Ac. baumannii phages, Βϕ-R1215 and Βϕ-R2315, were isolated from sewage samples. These phages were characterized by transmission electron microscopy, host spectrum, the thermal/pH stability test, the bacterial lysis assay and the whole genome analysis. Both phages lysed 21 of 45 CRAB hosts, and showed high stability at various pH (pH 4-10) and temperature (25-60°C), and were strongly active against host bacteria in vitro. The genomes of Βϕ-R1215 and Βϕ-R2315 are linear double-strands of DNA with 44·866 and 44·846 bp respectively. These two genomes revealed high similarity at the DNA level, but the organization and direction of open reading frames were different. CONCLUSIONS: The Ac. baumannii phages, Βϕ-R1215 and Βϕ-R2315, are novel lytic phages lysing CRAB strains which were isolated from respiratory samples of patients. SIGNIFICANCE AND IMPACT OF THE STUDY: In vitro and in silico data showed that these novel Ac. baumannii phages, Βϕ-R1215 and Βϕ-R2315, have potential as antimicrobial alternatives to control CRAB in healthcare settings.

Three-dimensional isotropic fast spin-echo MR lymphangiography of T1-weighted and intermediate-weighted pulse sequences in patients with lymphoedema.

AIM: To evaluate the feasibility of magnetic resonance (MR) lymphangiography acquired using three-dimensional (3D) isotropic T1-weighted fast spin-echo (FSE) and 3D isotropic intermediate-weighted FSE sequences, as the new method of MR lymphangiography, and to compare the results of these two methods in patients with lymphoedema. MATERIALS AND METHODS: Thirty-three extremities of 27 patients with primary or secondary lymphoedema and who had undergone radionuclide lymphoscintigraphy and MR lymphangiography with 3D isotropic T1-weighted FSE and 3D isotropic intermediate-weighted FSE were included in the study. The results of both imaging techniques were independently reviewed by two readers in consensus who rated the lymphatic drainage pattern, the quality of the depiction of lymphatic vessels and lymph nodes, and the level of lymph vessel enhancement. The assessment scores of each imaging sequence were compared using the Wilcoxon signed-rank test. The results were expressed as means with standard deviations. RESULTS: More lymphatic vessels were visualised on T1-weighted FSE than on intermediate-weighted FSE (p<0.001). As more lymphatic vessels were detected on T1-weighted FSE, the per-extremity grade of the lymphatic drainage pattern was higher (p=0.046) and the visible levels of lymph-vessel enhancement were also significantly higher (p=0.004) on the T1-weighted FSE sequence, whereas the conspicuity of lymph nodes was superior on intermediate-weighted FSE (p=0.004). CONCLUSION: MR lymphangiography using the 3D FSE pulse sequence is a feasible and noticeable new technique of MR lymphangiography. Between the two applicable protocols used, T1-weighted FSE provided better information regarding lymphatic vessels and their drainage, whereas intermediate-weighted FSE has the advantage of depicting lymph nodes in lymphoedematous extremities.

Inflammatory Bowel Disease Patients' Participation, Attitude and Preferences Toward Exercise.

The purpose of the study was to investigate the level of exercise participation in patients with inflammatory bowel disease (IBD) and to investigate their intention, attitude and preference toward exercise. The data of 158 IBD patients that participated in a self-administered survey at Severance Hospital between March 2013 and November 2013 were included in this cross sectional and descriptive analysis. Questionnaires included 3 sections to determine the IBD patient's current exercise participation, attitude toward exercise, and exercise preferences. This study investigated IBD patients both collectively, and according to their specific disease: Crohn's disease (CD) (n=62), Ulcerative colitis (UC) (n=73) and intestinal Behçet's disease (BD) (n=23). IBD patients currently participate in 103 min/week of exercise including mild, moderate and strenuous intensity, with BD patients being the least active, followed by CD, and UC being most active. The majority of IBD patients found exercise to be pleasant (57.7%), beneficial (80.5%), sensible (71.8%), uplifting (61%) and good (70.5%), and 44.4% found exercise to be enjoyable. This study shows the IBD patients' participation, attitude and preferences toward exercise and provides much needed information for the development of evidence based exercise programs that are specific to IBD.

Simultaneous determination of water-soluble whitening ingredients and adenosine in different cosmetic formulations by high-performance liquid chromatography coupled with photodiode array detection.

OBJECTIVE: The Korean Cosmetic Act regulates the use of functional cosmetics) by the law. Four functional cosmetic groups, whitening, anti-wrinkle, UV protection and combination of whitening and anti-wrinkle, were categorized according to the Korean Cosmetic Act and Functional Cosmetics Codex. In this study, high-performance liquid chromatography (HPLC) coupled with photodiode array detection (DAD) was employed for the simultaneous detection of arbutin (and its decomposition product, hydroquinone), niacinamide, ascorbyl glucoside, ethyl ascorbyl ether and adenosine in functional cosmetic products such as creams, emulsions and lotions. METHODS: Separation by HPLC-DAD was conducted using a C18 column with a gradient elution of 5 mm KH2PO4 buffer (containing 0.1% phosphoric acid) and methanol (containing 0.1% phosphoric acid). The wavelengths for the detection of arbutin, hydroquinone, niacinamide, adenosine, ascorbyl glucoside and ethyl ascorbyl ether were 283, 289, 261, 257, 238 and 245 nm, respectively. RESULTS: This method exhibited good linearity (R(2) ≥ 0.999), precision (expressed as relative standard deviation (RSD) < 2%) and mean recoveries (89.42-104.89%). The results obtained by monitoring 100 market samples showed that the detected levels of the tested materials are within the acceptable authorized concentration. CONCLUSION: The method developed herein is simple and can be used for market survey and quality control of functional cosmetics.

The siRNA cocktail targeting interleukin 10 receptor and transforming growth factor-ß receptor on dendritic cells potentiates tumour antigen-specific CD8(+) T cell immunity.

Dendritic cells (DCs) are promising therapeutic agents in the field of cancer immunotherapy due to their intrinsic immune-priming capacity. The potency of DCs, however, is readily attenuated immediately after their administration in patients as tumours and various immune cells, including DCs, produce various immunosuppressive factors such as interleukin (IL)-10 and transforming growth factor (TGF)-ß that hamper the function of DCs. In this study, we used small interfering RNA (siRNA) to silence the expression of endogenous molecules in DCs, which can sense immunosuppressive factors. Among the siRNAs targeting various immunosuppressive molecules, we observed that DCs transfected with siRNA targeting IL-10 receptor alpha (siIL-10RA) initiated the strongest antigen-specific CD8(+) T cell immune responses. The potency of siIL-10RA was enhanced further by combining it with siRNA targeting TGF-ß receptor (siTGF-ßR), which was the next best option during the screening of this study, or the previously selected immunoadjuvant siRNA targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN) or Bcl-2-like protein 11 (BIM). In the midst of sorting out the siRNA cocktails, the cocktail of siIL-10RA and siTGF-ßR generated the strongest antigen-specific CD8(+) T cell immunity. Concordantly, the knock-down of both IL-10RA and TGF-ßR in DCs induced the strongest anti-tumour effects in the TC-1 P0 tumour model, a cervical cancer model expressing the human papillomavirus (HPV)-16 E7 antigen, and even in the immune-resistant TC-1 (P3) tumour model that secretes more IL-10 and TGF-ß than the parental tumour cells (TC-1 P0). These results provide the groundwork for future clinical development of the siRNA cocktail-mediated strategy by co-targeting immunosuppressive molecules to enhance the potency of DC-based vaccines.

The flavone eupatilin inhibits eotaxin expression in an NF-κB-dependent and STAT6-independent manner.

The CC chemokine eotaxin contributes to epithelium-induced inflammation in airway diseases such as asthma. Eupatilin (5,7-dihydroxy-3',4',6'-trimethoxyflavone), a bioactive component of Artemisia asiatica Nakai (Asteraceae), is reported to inhibit the adhesion of eosinophils to bronchial epithelial cells. However, little is known about the molecular mechanism of eupatilin-induced attenuation of bronchial epithelium-induced inflammation. In this study, we investigated the effect of eupatilin on expression of eotaxin-1 (CCL11), a potent chemoattractant for eosinophils. Eupatilin significantly inhibited eotaxin expression in bronchial epithelial cells stimulated with TNF-α, while NF-κB and IκBα kinase (IKK) activities declined concurrently. Eupatilin also inhibited mitogen-activated protein kinase (MAPK) activity; however, all of these anti-inflammatory activities were reversed by MAPK overexpression. In contrast, eupatilin did not affect the signal transducer and activator of transcription 6 (STAT6) signalling in bronchial epithelial cells stimulated with IL-4. Furthermore, eupatilin significantly attenuated TNF-α-induced eosinophil migration. These results suggest that the eupatilin inhibits the signalling of MAPK, IKK, NF-κB and eotaxin-1 in bronchial epithelial cells, leading to inhibition of eosinophil migration.

Identification of anti-biofilm components in Withania somnifera and their effect on virulence of Streptococcus mutans biofilms.

AIMS: The aim of this study was to identify components of the Withania somnifera that could show anti-virulence activity against Streptococcus mutans biofilms. METHODS AND RESULTS: The anti-acidogenic activity of fractions separated from W. somnifera was compared, and then the most active anti-acidogenic fraction was chemically characterized using gas chromatography-mass spectroscopy. The effect of the identified components on the acidogenicity, aciduricity and extracellular polymeric substances (EPS) formation of S. mutans UA159 biofilms was evaluated. The change in accumulation and acidogenicity of S. mutans UA159 biofilms by periodic treatments (10 min per treatment) with the identified components was also investigated. Of the fractions, n-hexane fraction showed the strongest anti-acidogenic activity and was mainly composed of palmitic, linoleic and oleic acids. Of the identified components, linoleic and oleic acids strongly affected the acid production rate, F-ATPase activity and EPS formation of the biofilms. Periodic treatment with linoleic and oleic acids during biofilm formation also inhibited the biofilm accumulation and acid production rate of the biofilms without killing the biofilm bacteria. CONCLUSIONS: These results suggest that linoleic and oleic acids may be effective agents for restraining virulence of S. mutans biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY: Linoleic and oleic acids may be promising agents for controlling virulence of cariogenic biofilms and subsequent dental caries formation.

Overexpression of succinyl-CoA synthase for poly (3-hydroxybutyrate-co-3-hydroxyvalerate) production in engineered Escherichia coli BL21(DE3).

AIM: This study aims to increase the 3-hydroxyvalerate (3HV) fraction in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB-co-HV)] using succinyl-CoA synthase. METHODS AND RESULTS: Escherichia coli YH090, a polyhydroxyalkonate (PHA)-producing strain, was further engineered for overexpression of succinyl-CoA synthase genes (sucCD), and examined for P(HB-co-HV) copolymer production in the presence of various precursor molecules using mixture analysis. Glycerol, succinate and propionate were screened as important factors for controlling intracellular PHA accumulation and monomer composition. Glycerol concentrations exerted the greatest influence on the overall biomass concentration and the intracellular PHA content, while propionate concentrations in the presence of succinate influenced the 3HV content of the copolymer. Mixture analysis also demonstrated that the engineered strain has the capacity to accumulate up to 80% of its cell dry weight (CDW) as PHA with a variable fraction of 3HV monomer (maximum of 72 wt %) depending on the controlled conditions. CONCLUSIONS: Propionate is the principal precursor for 3HV monomer in P(HB-co-HV) biopolymer and its utilization requires conversion to propionyl-CoA. Engineered E. coli YHY99, overexpressing sucCD genes, leads to an increase of the succinyl-CoA pool, which enhances the conversion rate of propionate by providing a CoA supply to other acyltransferase enzymes that have a role in propionate utilization. SIGNIFICANCE AND IMPACT OF THE STUDY: Engineered E. coli YHY99 was able to utilize propionate with a 4·5-fold increase in rate, as compared to the control strain, and resulted in the synthesis of a copolymer with high 3HV monomer content.

Effect of brief cetylpyridinium chloride treatments during early and mature cariogenic biofilm formation.

OBJECTIVES: The aim of this study was to investigate the antibiofilm activity of brief cetylpyridinium chloride (CPC) treatments during early and mature Streptococcus mutans biofilm formation. METHODS: Streptococcus mutans biofilms were formed on saliva-coated hydroxyapatite disks. The biofilms were treated with CPC twice daily (1 min/treatment) from 0 to 50 h or from 48 to 98 h. Acidogenicity, dry weight, viability, and water-insoluble extracellular polysaccharides of the biofilms were analyzed. Confocal laser scanning microscopy (CLSM) images were obtained to confirm the antibiofilm activity during mature biofilm formation and to evaluate the relationship between treatment time and the antibiofilm activity. RESULTS: CPC showed complete antibiofilm activity during early biofilm formation at 0.025% to 0.1%. During mature biofilm formation, CPC inhibited dry weight, viability, and acidogenicity at 0.075% and 0.1%. CLSM images showed an increase in dead cells at 0.075% and 0.1% CPC. The antibiofilm activity during mature biofilm formation increased as the concentration of CPC increased. Images from the CLSM study also showed that antibiofilm activity increased as treatment time increased. CONCLUSION: Our findings suggest that brief CPC treatments have strong anti-S. mutans biofilm activity. The antibiofilm activity was dependent on the stage of biofilm formation, CPC concentration, and treatment time.