Prophylactic intravenous tranexamic acid and thromboembolism in non-cardiac surgery: a systematic review, meta-analysis and trial sequential analysis.

Tranexamic acid is an antifibrinolytic drug that is widely used during surgery, but there are concerns about its thromboembolic effects. We aimed to investigate the effect of prophylactic intravenous tranexamic acid on thromboembolic outcomes in patients undergoing non-cardiac surgery. The MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials were searched. Randomised controlled trials comparing intravenous tranexamic acid with placebo or no treatment in patients undergoing non-cardiac surgery were included. The primary outcome was a composite of peri-operative cardiovascular thromboembolic events, defined as any deep vein thrombosis, pulmonary embolism, myocardial ischaemia/infarction or cerebral ischaemia/infarction. A total of 191 randomised controlled trials (40,621 patients) were included in the review. The primary outcome occurred in 4.5% of patients receiving intravenous tranexamic acid compared with 4.9% of patients in the control group. Our analysis showed that there was no difference between groups for composite cardiovascular thromboembolic events (risk ratio 1.02, 95%CI 0.94-1.11, p = 0.65, I2 0%, n = 37,512). This finding remained robust when sensitivity analysis was performed with continuity correction and in studies with a low risk of bias. However, in trial sequential analysis, our meta-analysis only achieved 64.6% of the required information size. There was no association between intravenous tranexamic acid and seizure rate or mortality rate within 30 days. Intravenous tranexamic acid was associated with a reduced blood transfusion rate compared with control (9.9% vs. 19.4%, risk ratio 0.46, 95%CI 0.41-0.51, p < 0.0001). It was encouraging to see the evidence that the administration of intravenous tranexamic in patients undergoing non-cardiac surgery was not associated with an increased risk of thromboembolic outcomes. However, our trial sequential analysis demonstrated that currently available evidence is not yet sufficient to reach a firm conclusion.

Single-incision robotic colorectal surgery with the da Vinci SP® surgical system: initial results of 50 cases.

PURPOSE: The da Vinci SP® (dVSP) surgical system (Intuitive Surgical, Sunnyvale, CA, USA), a robotic platform designed for single-incision surgery, overcame the need for multiple ports in traditional robotic surgery and issues including triangulation and retraction in single-incision laparoscopic surgery. However, previous studies only included case reports or series with small sample sizes. The aim of this study was to assess the safety and performance of the dVSP surgical system and its instruments and accessories for colorectal procedures. METHODS: The medical records of patients who had surgery with the dVSP from March 2019 to September 2021 at Ewha Womans University Seoul Hospital were investigated. The pathologic and follow-up data of patients who had malignant tumors were analyzed separately to evaluate oncological safety. RESULTS: Fifty patients (26 male and 24 female) with a median age of 59 years (interquartile range 52.5-63.0 years) were enrolled. The procedures included low anterior resection with total mesorectal excision (n = 16), sigmoid colectomy with complete mesocolic excision and central vessel ligation (CME + CVL) (n = 14), right colectomy with CME + CVL (n = 9), left colectomy with CME + CVL (n = 4), right colectomy (n = 6), and sigmoid colectomy (n = 1). Operative time significantly decreased after 25 cases (early phase vs. late phase; operative time 295.0 min vs. 250.0 min, p = 0.015; docking time 16.0 min vs. 12.0 min, p = 0.001; console time 212.0 min vs. 190.0 min, p = 0.019). Planned procedures were successfully completed in all patients. Postoperative outcomes were acceptable with only six cases of mild adverse events through a 3-month follow-up. No local recurrence and only one case of systemic recurrence occurred within 1 year postoperatively. CONCLUSIONS: This study demonstrated the surgical and oncological safety and feasibility of dVSP, which may be a novel surgical platform for colorectal surgery.

Surgical management of pelvic organ prolapse.

Despite pelvic organ prolapse being a universal problem experienced in nearly 50% of parous women, the surgical management of vaginal prolapse remains an enigma to many, with wide variation in the rates and types of intervention performed. As part of the 6th International Consultation on Incontinence (ICI) our committee, charged with producing an evidence-based report on the surgical management of prolapse, produced a pathway for the surgical management of prolapse. The 2017 ICI surgical management of prolapse evidence-based pathway will be presented and summarized. Weaknesses of the data and pathway will be discussed and avenues for future research proposed.

Col2-Cre and tamoxifen-inducible Col2-CreER target different cell populations in the knee joint.

OBJECTIVE: Collagen type 2 (Col2)-Cre or tamoxifen-inducible Col2-CreER transgenic mouse lines have been used for studies to explore the cellular and molecular pathogenesis of osteoarthritis (OA). The purpose of this study is to investigate whether the targeted cells are the same or different in the two mouse lines. METHODS: We crossed tamoxifen inducible Col2-CreER and Col2-Cre mice with Rosa tdTomato reporter mice and analyzed the labeling patterns at different time points. RESULTS: In the Col2-CreER mice, 90.8 [95% confidence interval (CI) (88.3, 93.2)] and 82.8 (77.4, 88.3) % of the articular surface cells are Tomato positive when tamoxifen was administered at 2 and 2.5 weeks of age and strong activity was observed even 4.5 months after injection. However, 46.0 (32.8, 59.1) and 22.2 (11.7, 32.6) % of the surface cells were Tomato positive when tamoxifen was administered at 3 and 4 weeks of age, respectively. Little to no Tomato activity in the articular surface cells was observed when tamoxifen was administered at 8 weeks of age. At any stage of tamoxifen injection, the Tomato activity was detected in growth plate and epiphyseal bone in addition to articular chondrocytes, but little in endosteum and not in the synovium and ligament. In contrast, the targeted tissues in the Col2-Cre mouse line were articular cartilage, growth plate, meniscus, endosteum, ligament, bone and synovium. CONCLUSIONS: This study demonstrates that the pattern of targeted cells in the inducible Col2-CreER mice are partially overlapping with but different from that of targeted cells in Col2-Cre mice and the pattern varies dependent on when tamoxifen is administered.

Smoking status and its relationship with depression among the elderly population in Malaysia: Findings from the National Health and Morbidity Survey 2018.

INTRODUCTION: Literature exploring smoking status and its association with depression among the elderly population using nationwide data in Malaysia is limited. Hence, a nationwide survey to determine the prevalence of smoking and depression among the elderly (aged ≥60 years) population was undertaken. METHODS: This secondary dataset analysis used data from the National Health and Morbidity Survey (NHMS) 2018. Data from 3914 participants were collected on elderly health in the Malaysian population. Sociodemographic characteristics were recorded. Smoking status was grouped as current smokers, former smokers, and non-smokers. A validated Malay language version of the Geriatric Depression Scale (M-GDS-14) was used to screen for depression among the elderly. RESULTS: There was a significant association between smoking status with location, gender, employment status, marital status, ethnicity, education level, income, and depression. Current smokers are significantly higher in rural than urban areas. Among depressed participants, 65.7%, 17.1% and 17.2% were non-smokers, former smokers and current smokers, respectively. Multiple logistic regression showed that single (unmarried/separated/ divorced/widowed) participants were more likely to be depressed compared to married participants (AOR=1.68; 95% CI: 1.16-2.43). Whilst unemployed participants were more likely to be depressed than those who were employed (AOR=1.72; 95% CI: 1.22-2.44). Other Bumiputras were more likely to have depression compared to Malay, Chinese and Indian participants. Participants without formal education were more likely to be depressed compared to those having tertiary education. These participants have a 2-fold increased risk of depression (AOR=2.13; 95% CI: 1.02-4.45). Participants whose monthly salaries were <2000 MYR (AOR=3.67; 95% CI: 1.84-7.31) and 1000-1999 MYR (AOR=2.71; 95% CI: 1.23-5.94) were more likely to have depression compared with those who had received ≥3000 MYR. Ever smokers were more likely to be depressed than non-smokers (AOR=1.68; 95% CI: 1.23-2.29). CONCLUSIONS: Elderly Malaysians are indeed at risk of developing depression particularly if they had ever smoked. Public health awareness and campaigning are pertinent to disseminate these outcomes in order to spread the awareness associated with smoking-related depression.

Singapore Clinical Practice Guidelines For Sarcopenia: Screening, Diagnosis, Management and Prevention.

OBJECTIVES: To present the local evidence and final recommendations of the Clinical Practice Guidelines workgroup convened by the Chapter of Geriatricians and the Society for Geriatric Medicine Singapore. The aim is to develop contextualized evidence-based recommendations that facilitate adoption of the Asian Working Group for Sarcopenia (AWGS) 2019 consensus into current practice in Singapore. METHODS: The workgroup drew upon the AWGS'2019 consensus, updated literature review of Singapore studies till 31 Dec 2020, and evidence from recent systematic reviews. From 40 local studies included for data extraction, we constructed evidence tables organized as: definition and epidemiology; diagnosis and evaluation; and treatment and intervention. Twenty recommendations - case-finding, diagnosis, treatment, prevention, research - were developed, and graded for strength and quality using the GRADE approach. Consensus from an expert panel(N=23) was achieved after two rounds of the modified Delphi process. RESULTS: The local prevalence of sarcopenia among community-dwelling older adults ranged from 13.6% to 25%. Most studies adopted the AWGS'2019 and AWGS'2014 criteria. Reported case finding tools include SARC-F, calf circumference (CC) and SARC-CalF. Gender-specific AWGS cut-offs for appendicular skeletal mass were used to define low muscle mass. Different protocols and dynamometers were used to assess handgrip strength, whilst gait speed and 5-times chair stand were commonly used to assess physical performance. RECOMMENDATIONS: We conditionally recommend a case-finding approach in at-risk older adults using validated case-finding tools. Screen-positive individuals should be assessed for 'possible sarcopenia' and underlying causes. For diagnosis, we conditionally recommend using the AWGS'2019 algorithm, and dual-energy X-ray absorptiometry when necessary to determine low lean mass for a confirmatory diagnosis of sarcopenia. For treatment, we strongly recommend resistance-based exercises and conditionally recommend a quality protein-rich diet/protein supplementation, with Vitamin D supplementation for insufficiency (<30 micrograms/L). For prevention, we recommend regular resistance-based physical activity and adequate protein intake (≥1.0g/kg bodyweight). We encourage more research to address local evidence gaps.

Stress hyperglycaemia is associated with poor functional outcomes in patients with acute ischaemic stroke after intravenous thrombolysis.

BACKGROUND: Transient hyperglycaemia in the context of illness with or without known diabetes has been termed as 'stress hyperglycaemia'. Stress hyperglycaemia can result in poor functional outcomes in patients with acute ischaemic stroke (AIS) who underwent mechanical thrombectomy. We investigated the association between stress hyperglycaemia and clinical outcomes in AIS patients undergoing intravenous thrombolysis (IVT). METHODS: We examined 666 consecutive patients with AIS who underwent IVT from 2006 to 2018. All patients had a glycated haemoglobin level (HbA1c) and fasting venous blood glucose measured within 24 h of admission. Stress hyperglycaemia ratio (SHR) was defined as the ratio of the fasting glucose to the HbA1c. Univariate and multivariate analyses were employed to identify predictors of poor functional outcomes (modified Rankin Scale 3-6 at 3 months) after IVT. RESULTS: Three-hundred and sixty-one patients (54.2%) had good functional outcomes. These patients tended to be younger (60.7 ± 12.7 vs. 70 ± 14.4 years, P < 0.001), male (70.7% vs. 51.5%, P < 0.001), had lower prevalence of atrial fibrillation (13.0% vs. 20.7%, P = 0.008) and lower SHR (0.88 ± 0.20 vs. 0.99 ± 26, P < 0.001). Patients with high SHR (≥0.97) were slightly older than those with low SHR (<0.97) and were more likely to have diabetes mellitus. On multivariate analysis, higher SHR was independently associated with poor functional outcomes (adjusted odds ratio 3.85, 95% confidence interval 1.59-9.09, P = 0.003). CONCLUSION: SHR appears to be an important predictor of functional outcomes in patients with AIS undergoing IVT. This may have important implications on the role of glycaemic control in the acute management of ischaemic stroke.

Development, Validation and Field Evaluation of the Singapore Longitudinal Ageing Study (SLAS) Risk Index for Prediction of Mild Cognitive Impairment and Dementia.

BACKGROUND: Mild cognitive impairment (MCI) is a critical pre-dementia target for preventive interventions. There are few brief screening tools based on self-reported personal lifestyle and health-related information for predicting MCI that have been validated for their generalizability and utility in primary care and community settings. OBJECTIVE: To develop and validate a MCI risk prediction index, and evaluate its field application in a pilot community intervention trial project. DESIGN: Two independent population-based cohorts in the Singapore Longitudinal Ageing Study (SLAS). We used SLAS1 as a development cohort to construct the risk assessment instrument, and SLA2 as a validation cohort to verify its generalizability. SETTING: community-based screening and lifestyle intervention Participants: (1) SLAS1 cognitively normal (CN) aged ≥55 years with average 3 years (N=1601); (2) SLAS2 cohort (N=3051) with average 4 years of follow up. (3) 437 participants in a pilot community intervention project. MEASUREMENTS: The risk index indicators included age, female sex, years of schooling, hearing loss, depression, life satisfaction, number of cardio-metabolic risk factors (wide waist circumference, pre-diabetes or diabetes, hypertension, dyslipidemia). Weighted summed scores predicted probabilities of MCI or dementia. A self-administered questionnaire field version of the risk index was deployed in the pilot community project and evaluated using pre-intervention baseline cognitive function of participants. RESULTS: Risk scores were associated with increasing probabilities of progression to MCI-or-dementia in the development cohort (AUC=0.73) and with increased prevalence and incidence of MCI-or-dementia in the validation cohort (AUC=0.74). The field questionnaire risk index identified high risk individuals with strong correlation with RBANS cognitive scores in the community program (p<0.001). CONCLUSIONS: The SLAS risk index is accurate and replicable in predicting MCI, and is applicable in community interventions for dementia prevention.

Risk Factors of Progression to Frailty: Findings from the Singapore Longitudinal Ageing Study.

OBJECTIVES: To investigate risk factors of incident physical frailty. DESIGN: A population-based observational longitudinal study. SETTING: Community-dwelling elderly with age 55 years and above recruited from 2009 through 2011 in the second wave Singapore Longitudinal Ageing Study-2 (SLAS-2) were followed up 3-5 years later. PARTICIPANTS: A total of 1297 participants, mean age of 65.6 ±0.19, who were free of physical frailty. MEASUREMENTS: Incident frailty defined by three or more criteria of the physical phenotype used in the Cardiovascular Health Study was determined at follow-up. Potential risk factors assessed at baseline included demographic, socioeconomic, medical, psychological factors, and biochemical markers. RESULTS: A total of 204 (15.7%) participants, including 81 (10.87%) of the robust and 123 (22.28%) of the prefrail transited to frailty at follow-up. Age, no education, MMSE score, diabetes, prediabetes and diabetes, arthritis, ≥5 medications, fair and poor self-rated health, moderate to high nutritional risk (NSI ≥3), Hb (g/dL), CRP (mg/L), low B12, low folate, albumin (g/L), low total cholesterol, adjusted for sex, age and education, were significantly associated (p<0.05) with incident frailty. In stepwise selection models, age (year) (OR=1.07, 95%CI=1.03-1.10, p<0.001), albumin (g/L) (OR=0.85, 95%CI=0.77-0.94, p=0.002), MMSE score (OR=0.88, 95%CI=0.78-0.98, p=0.02), low folate (OR=3.72, 95%CI=1.17-11.86, p=0.03, and previous hospitalization (OR=2.26, 95%CI=1.01-5.04,p=0.05) were significantly associated with incident frailty. CONCLUSIONS: The study revealed multiple modifiable risk factors, especially related to poor nutrition, for which preventive measures and early management could potentially halt or delay the development of frailty.

The Changing Profile of Patients in a Geriatric Medicine Led Memory Clinic over 12 Years.

OBJECTIVES: Memory clinics play an important role in enabling early dementia diagnosis and intervention. Few studies have investigated the changing patient profiles at memory clinics over time. We studied the trend of patient characteristics in a geriatric medicine-led memory clinic over 12 years to improve services and care to meet their needs. SETTING AND PARTICIPANTS: Data from 2340 first-visit patients seen at a memory clinic from 2005-2017 were extracted from a registered database and analysed. DESIGN: ANOVA, Pearson chi-square and non-parametric tests were used to describe and compare between patients with dementia (PWD) and patients with no dementia (PND). MEASUREMENTS: Data included diagnoses of dementia and mild cognitive impairment, age, education, MMSE scores and comorbidities. RESULTS: Patients averaged 77.2 ± 8.3 years of age with mean MMSE score of 16.2 ± 6.7. Those diagnosed with dementia were older (78.3 ± 7.9 years) and almost half (48.4%) had moderate or moderately severe dementia (FAST 5-6). Over time, there was a growing proportion of patients with mild cognitive impairment (MCI) and mild Alzheimer's dementia. Many PWD had co-morbidities of hypertension (65.9%), hyperlipidemia (55.1%), diabetes (33.5%) and 28.4% were frail. CONCLUSIONS: The findings call for services to better diagnose and manage patients at the earlier stages of cognitive impairment and provide holistic interventions for those with frailty and other co-morbidities. The continued rise in number of patients presenting to memory clinics provides impetus to expedite integration of tertiary-based memory clinics with primary and community care providers to better support PWD and their families.

A validation of dynamic causal modelling for 7T fMRI.

BACKGROUND: There is growing interest in ultra-high field magnetic resonance imaging (MRI) in cognitive and clinical neuroscience studies. However, the benefits offered by higher field strength have not been evaluated in terms of effective connectivity and dynamic causal modelling (DCM). NEW METHOD: In this study, we address the validity of DCM for 7T functional MRI data at two levels. First, we evaluate the predictive validity of DCM estimates based upon 3T and 7T in terms of reproducibility. Second, we assess improvements in the efficiency of DCM estimates at 7T, in terms of the entropy of the posterior distribution over model parameters (i.e., information gain). RESULTS: Using empirical data recorded during fist-closing movements with 3T and 7T fMRI, we found a high reproducibility of average connectivity and condition-specific changes in connectivity - as quantified by the intra-class correlation coefficient (ICC = 0.862 and 0.936, respectively). Furthermore, we found that the posterior entropy of 7T parameter estimates was substantially less than that of 3T parameter estimates; suggesting the 7T data are more informative - and furnish more efficient estimates. COMPARED WITH EXISTING METHODS: In the framework of DCM, we treated field-dependent parameters for the BOLD signal model as free parameters, to accommodate fMRI data at 3T and 7T. In addition, we made the resting blood volume fraction a free parameter, because different brain regions can differ in their vascularization. CONCLUSIONS: In this paper, we showed DCM enables one to infer changes in effective connectivity from 7T data reliably and efficiently.

A pilot study on the Chinese Minnesota Multiphasic Personality Inventory-2 in detecting feigned mental disorders: Simulators classified by using the Structured Interview of Reported Symptoms.

The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) is often used in forensic psychological/psychiatric assessment. This was a pilot study on the utility of the Chinese MMPI-2 in detecting feigned mental disorders. The sample consisted of 194 university students who were either simulators (informed or uninformed) or controls. All the participants were administered the Chinese MMPI-2 and the Structured Interview of Reported Symptoms-2 (SIRS-2). The results of the SIRS-2 were utilized to classify the participants into the feigning or control groups. The effectiveness of eight detection indices was investigated by using item analysis, multivariate analysis of covariance (MANCOVA), and receiver operating characteristic (ROC) analysis. Results indicated that informed-simulating participants with prior knowledge of mental disorders did not perform better in avoiding feigning detection than uninformed-simulating participants. In addition, the eight detection indices of the Chinese MMPI-2 were effective in discriminating participants in the feigning and control groups, and the best cut-off scores of three of the indices were higher than those obtained from the studies using the English MMPI-2. Thus, in this sample of university students, the utility of the Chinese MMPI-2 in detecting feigned mental disorders was tentatively supported, and the Chinese Infrequency Scale (ICH), a scale developed specifically for the Chinese MMPI-2, was also supported as a valid scale for validity checking.

The essential role of H2O2 in the regulation of intracellular Ca2+ by epidermal growth factor in rat-2 fibroblasts.

We have investigated a new mechanism by which epidermal growth factor (EGF) increases intracellular Ca(2+) ([Ca(2+)](i)) in Rat-2 fibroblasts. EGF induced a transient increase of [Ca(2+)](i), and sustained Ca(2+) increase disappeared in the absence of extracellular Ca(2+). However, EGF had no effect on the formation of inositol phosphates. Expression of N17Rac or scrape-loading of C3 transferase blocked the elevation of [Ca(2+)](i) by EGF, but not by lysophosphatidic acid (LPA). EGF increased intracellular H(2)O(2), with a maximal increase at 5 min, which was blocked by catalase, scrape-loading of C3 transferase, or expression of N17Rac. H(2)O(2) scavengers, catalase and N-acetyl-L-cysteine, also blocked the Ca(2+) response to EGF, but not to LPA. In the presence of EGTA, preincubation with EGF completely inhibited subsequent Ca(2+) response to extracellular H(2)O(2) and vice versa. Incubation with EGF or phosphatidic acid abolished subsequent elevation of [Ca(2+)](i) by phosphatidic acid or EGF, respectively. Furthermore, preincubation with LPA inhibited the subsequent Ca(2+) response to EGF, but not vice versa. These results suggested that intracellular H(2)O(2) regulated by Rac and RhoA, but not inositol phosphates, was responsible for the EGF-stimulated elevation of [Ca(2+)](i). It was also suggested that EGF cross talked with LPA in the regulation of [Ca(2+)](i) by producing intracellular H(2)O(2).

Phenotype and function of nasal dendritic cells.

Intranasal (i.n.) vaccination generates immunity across local, regional, and distant sites. However, nasal dendritic cells (DCs), pivotal for the induction of i.n. vaccine-induced immune responses, have not been studied in detail. Here, by using a variety of parameters, we define nasal DCs in mice and humans. Distinct subsets of "classical" DCs, dependent on the transcription factor zbtb46 were identified in the murine nose. The murine nasal DCs were Fms-related tyrosine 3 kinase ligand responsive and displayed unique phenotypic and functional characteristics, including the ability to present antigen, induce an allogeneic T-cell response, and migrate in response to lipopolysaccharide or live bacterial pathogens. Importantly, in a cohort of human volunteers, BDCA-1(+) DCs were observed to be the dominant nasal DC population at steady state. During chronic inflammation, the frequency of both BDCA-1(+) and BDCA-3(hi) DCs was reduced in the nasal tissue, associating the loss of these immune sentinels with chronic nasal inflammation. The present study is the first detailed description of the phenotypic, ontogenetic, and functional properties of nasal DCs, and will inform the design of preventative immunization strategies as well as therapeutic modalities against chronic rhinosinusitis.

Solution structure of an antimicrobial peptide buforin II.

The structure of 21-residue antimicrobial peptide buforin II has been determined by using NMR spectroscopy and restrained molecular dynamics. Buforin II adopts a flexible random structure in H2O. In trifluoroethanol (TFE)/H2O (1:1, v/v) mixture, however, buforin II assumes a regular alpha-helix between residues Val12 and Arg20 and a distorted helical structure between residues Gly7 and Pro11. The model structure obtained shows an amphipathic character in the region from Arg5 to the C-terminus, Lys21. Like other known cationic antimicrobial peptides, the amphipathic structure might be the key factor for antimicrobial activity of buforin II.

One micrometer resolution NMR microscopy.

We obtained a magnetic resonance image of 1 microm resolution and 75 microm(3) voxel volume for a phantom filled with hydrocarbon oil within an hour at 14.1 T. For this work, a specially designed probe with a high sensitivity RF coil and gradient coils generating over 1000 G/cm was built. The optimal pulse sequence was analyzed in consideration of the bandwidth, diffusion coefficients, and T(1) and T(2) relaxations of the medium. The system was applied to the in vivo imaging of a geranium leaf stem to get the images of 2 microm resolution and 200 microm(3) voxel volume.

Aging affects two modes of nanoleakage expression in bonded dentin.

Water sorption into resin-dentin interfaces precedes hydrolytic degradation. We hypothesized that these processes are morphologically manifested by the uptake of ammoniacal silver nitrate, which is thought to trace hydrophilic domains and water-filled channels within matrices. Water sorption is thought to be nonuniform and can be traced by the use of silver nitrate. Human teeth bonded with an experimental filled-adhesive were aged in artificial saliva (experimental) or non-aqueous mineral oil (control). Specimens retrieved for up to a 12-month period were immersed in 50 wt% ammoniacal silver nitrate and examined by transmission electron microscopy for identification of the changes in their silver uptake. Reticular silver deposits initially identified within the bulk of hybrid layers in the experimental group were gradually reduced over time, but were subsequently replaced by similar deposits that were located along the hybrid layer-adhesive interface. Silver uptake in water-binding domains of the adhesive layers increased with aging, resulting in water tree formation. These water-filled channels may act as potential sites for hydrolytic degradation of resin-dentin bonds.

Structural characterization of beta-D-(1 --> 3, 1 --> 6)-linked glucans using NMR spectroscopy.

Nondestructive structural analysis of a series of beta-D-(1 --> 3, 1 --> 6)-linked glucans (laminaran, curdlan, yeast glucan, scleroglucan, etc.) was performed using two-dimensional NMR spectroscopy. The relative ratios of H-1 at different AGUs provided the information about DPn and DB. The alpha-, and beta-anomeric protons on reducing terminals were assigned at 5.02 to approximately 5.03 ppm (J 3.6 to approximately 3.7 Hz), and 4.42 to approximately 4.43 ppm (J 7.6 to approximately 7.9 Hz), respectively, whereas the H-1 protons of internal AGUs and beta-(1 --> 6)-branched AGUs appeared at 4.56 to approximately 4.59 ppm (J 7.6 to approximately 7.8 Hz), and 4.26 to approximately 4.28 ppm (J 7.6 to approximately 10.6 Hz), respectively, in a mixed solvent of 6:1 Me2SO-d6-D2O at 80 degrees C. In the solvent, the OH peaks were eliminated from the spectra allowing the H-1 protons to appear clearly. In addition, the nonreducing terminal H-1 and H-1 at the AGU next to reducing terminal could be assigned at 4.45 to approximately 4.46 ppm (J 7.8 to approximately 7.9 Hz), and 4.51 to approximately 4.53 ppm (J 7.8 Hz), respectively. The DPn of the laminaran was 33 (polydispersity 1.12) and the DB was 0.07. The number of glucosyl units in the side chain of laminaran is more than one. The DPn and DB of the water-insoluble yeast glucan were 228 and 0.003, respectively. However the DPn of water soluble yeast glucan phosphate and curdlan was changed upon the number of freeze-drying processes and the content of water in the mixed solvent, respectively. And the DB of those were calculated as 0.02 and 0, respectively. The DB of scleroglucan was precisely calculated as 0.33, compared with the previously reported data. The H-1s at different AGUs of the various beta-D-(1 --> 3, 1 --> 6)-linked glucans having different DB can be exactly assigned by their chemical shifts in the mixed solvent system. This NMR analysis can be effectively used to determine the DP and DB of polysaccharides in a simple and non-destructive manner.