The hindbrain and cortico-reticular pathway in adolescent idiopathic scoliosis

AIM

To characterise the corticoreticular pathway (CRP) in a case-control cohort of adolescent idiopathic scoliosis (AIS) patients using high-resolution slice-accelerated readout-segmented echo-planar diffusion tensor imaging (DTI) to enhance the discrimination of small brainstem nuclei in comparison to automated whole-brain volumetry and tractography and their clinical correlates.

MATERIALS AND METHODS

Thirty-four participants (16 AIS patients, 18 healthy controls) underwent clinical and orthopaedic assessments and brain magnetic resonance imaging (MRI) on a 3 T MRI machine. Automated whole-brain volume-based morphometry, tract-based spatial statistics analysis, and manual CRP tractography by two independent raters were performed. Intra-rater and inter-rater agreement of DTI metrics from CRP tractography were assessed by intraclass correlation coefficient. Normalised structural brain volumes and DTI metrics were compared between groups using Student's t-tests. Linear correlation analysis between imaging parameters and clinical scores was also performed.

RESULTS

AIS patients demonstrated a significantly larger pons volume compared to controls (p=0.006). Significant inter-side CRP differences in mean (p=0.02) and axial diffusivity (p=0.01) were found in patients only. Asymmetry in CRP fractional anisotropy significantly correlated with the Cobb angle (p=0.03).

CONCLUSION

Relative pontine hypertrophy and asymmetry in CRP DTI metrics suggest central supranuclear inter-hemispheric imbalance in AIS, and support the role of the CRP in axial muscle tone. Longitudinal evaluation of CRP DTI metrics in the prediction of AIS progression may be clinically relevant.

Reporting of coronary artery calcification on chest CT studies in patients with interstitial lung disease

AIM

To evaluate the prevalence of coronary artery calcification (CAC) on non-contrast computed tomography (CT) of the thorax in patients with interstitial lung disease (ILD), assess consistency of CAC reporting and assess incidence of subsequent cardiac events.

MATERIALS AND METHODS

Patients with known interstitial lung disease who underwent a CT thorax over a 2-year period were retrospectively reviewed. Presence of CAC was assessed using a visual scale for CAC reporting and graded as mild, moderate, or severe by two cardiothoracic radiologists. CT reports were reviewed to determine if presence of CAC had been described. Electronic medical records were reviewed for any subsequent cardiothoracic events from the date of the CT thorax to present.

RESULTS

254 patients were included in the analysis (54.7% men; mean age 59.9 yo). 43.7% had CAC on their CT thorax; however, in 87.3% of those, reports did not comment on its presence. 8 patients had cardiac events; 7 of them had CAC on CT although only in 1 case this was reported. Global CAC and LAD CAC Patients with cardiac events had a significantly higher global CAC (p=0.016) and LAD CAC (p=0.048) when compared to patients without.

CONCLUSION

We demonstrated a high prevalence of CAC in ILD patients and its significant association with adverse cardiac events. Unfortunately, CAC on CT thorax is still largely unreported. As per recent BSCI/BSCCT and BSTI guidelines, reporting of CAC should become part of routine practice, as may prompt prevention and impact on patients outcome.

[Observation on the efficacy of different targets low-frequency repetitive transcranial magnetic stimulation for the treatment of tremor-dominant subtypes of Parkinson's disease]

Objective: To analyze the efficacy of different targets low-frequency repetitive transcranial magnetic stimulation (rTMS) for the treatment of tremor Parkinson's disease(PD). Method: A total of 82 patients with primary PD who were admitted to the Department of Neurology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from April 1, 2020 to March 31, 2021 were prospectively collected. According to the clinical characteristics of major movement disorders, 82 patients with tremor type (TD) were selected to enroll.The patients were randomly divided into 3 groups at a 1∶1∶1 ratio according to the randomized coding sequence of the trial: the primary motor cortex (M1) group with 26 cases, the cerebellum group with 26 cases and the dual-site (M1, cerebellum) group with 30 cases. All patients were treated with 1 Hz low-frequency stimulation of the corresponding target once a day for 5 days a week for 2 weeks, a total of 10 times; The dosage remained unchanged during the treatment for all groups. Before and after 2 weeks' treatment, the patients were assessed with the Unified PD Rating Scale (UPDRS) and PD Quality of Life Questionnaire-39 (PDQ-39) without medication. Cortical excitability, namely transcranial magnetic stimulation motor evoked potential (TMS-MEP), [including resting motor threshold (rMT) and active motor threshold (aMT) examinations], timed up and go (TUG) and electromyographic tremor were conducted. Result: There were 82 patients, 39 males and 43 females, with an average age of (67±8) years. Before the treatment, there was no statistically significant difference in the evaluation indicators among the three groups (all P>0.05). After the treatment, the differences of the UPDRS-Ⅲ score [(38.9±2.5) vs (29.2±3.6) ], UPDRS tremor score [(23.7±2.1) vs (14.6±3.1) ], TUG time [(44.8±3.1) s vs (33.7±4.1) s], tremor amplitude [(480±126) μV vs (276±94) μV], PDQ-39 score [(51±13) vs (45±13) ], rMT [(36±17)% vs (43±13)%], and aMT [(26±16)% vs (31±12)%] were statistically significant (all P<0.01) from those before the treatment. There was no statistical difference in the above factors between the M1 group and cerebellum group (all P>0.05). There was no statistically significant difference in tremor peak frequency among the three groups before and after the treatment (all P>0.05). Conclusions: Dual-site low-frequency rTMS can improve PD tremor, while M1 or cerebellar low-frequency rTMS does not significantly improve PD tremor. Its mechanism may be to improve PD tremor symptoms by regulating cortical excitability.

Focalizing regions of biomarker relevance facilitates biomarker prediction on histopathological images

Image-based AI has thrived as a potentially revolutionary tool for predicting molecular biomarker statuses, which aids in categorizing patients for appropriate medical treatments. However, many methods using hematoxylin and eosin-stained (H&E) whole-slide images (WSIs) have been found to be inefficient because of the presence of numerous uninformative or irrelevant image patches. In this study, we introduced the region of biomarker relevance (ROB) concept to identify the morphological areas most closely associated with biomarkers for accurate status prediction. We actualized this concept within a framework called saliency ROB search (SRS) to enable efficient and effective predictions. By evaluating various lung adenocarcinoma (LUAD) biomarkers, we showcased the superior performance of SRS compared to current state-of-the-art AI approaches. These findings suggest that AI tools, built on the ROB concept, can achieve enhanced molecular biomarker prediction accuracy from pathological images.

[Synchronization isolation method for multiple types of cells from mouse liver]

Objective: To explore a simple and feasible method for the isolation and purification of hepatocytes, hepatic stellate cells (HSC), and lymphocytes from mice. Methods: The cell suspension was obtained from male C57bl/6 mice by hepatic perfusion through the portal vein digestion method and then isolated and purified by discontinuous Percoll gradient centrifugation. Trypan blue exclusion was used to determine cell viability. Glycogen staining, cytokeratin 18, and transmission electron microscopy were used to identify hepatic cells. Immunofluorescence was used to detect α-smooth muscle actin combined with desmin in HSCs. Flow cytometry was used to analyze lymphocyte subsets in the liver. Results: After isolation and purification, about 2.7×10(7) hepatocytes, 5.7×10(5) HSCS, and 4.6×106 hepatic mononuclear cells were obtained from the liver of mice with a body weight of about 22g. The cell survival rate in each group was > 95%. Hepatocytes were apparent in glycogen deposited purple-red granules and cytokeratin 18. Electron microscopy showed that there were abundant organelles in hepatocytes and tight junctions between cells. HSC had expressed α-smooth muscle actin and desmin. Flow cytometry showed hepatic mononuclear cells, including lymphocyte subsets such as CD4, CD8, NKs, and NKTs. Conclusion: The hepatic perfusion through the portal vein digestion method can isolate multiple primary cells from the liver of mice at once and has the features of simplicity and efficiency.

1332 PREVALENCE AND OUTCOMES OF FRAILTY IN OLDER PEOPLE WITH UNPLANNED HOSPITAL ADMISSIONS: SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Guidelines recommend screening for frailty in all hospitalised older adults to inform care, based mainly on studies in outpatient and speciality-specific settings. However, most hospital bed-days in older people are for acute, non-elective admissions to general medicine, for which the prevalence and prognostic value of frailty might differ. Therefore, we undertook a systematic review of frailty prevalence and outcomes in older people with unplanned hospital admissions.

Methods

We searched MEDLINE, EMBASE and CINAHL up to 30/04/2021 for observational studies using validated frailty measures in unplanned adult hospital-wide or general medicine admissions. We related frailty prevalence to measurement tool, setting and risk of bias (RoB). Relative risks (RR) for mortality, length of stay (LOS), discharge destination and readmission were pooled using random-effects models where appropriate, and area-under-the-ROC-curves calculated. Heterogeneity was explored with meta-regression. Dose-response effects were assessed with the Cochran-Armitage test.

Results

Among 38 cohorts (median/SD age=80/5 years; n=37,733,147 admissions), the median prevalence of moderate-severe frailty was 40.5% (IQR=33.2-53.2; low-moderate RoB=23/38), with considerable heterogeneity (PQ&lt;0.001) apparently unrelated to measure, setting or RoB. Nevertheless, frailty still predicted mortality (RR range=1.08-16.06), long LOS (range=1.35-3.04) and discharge destination (range=1.97-3.45) in all studies with more severe frailty associated with worse outcomes, although associations with 30-day readmission were conflicting (range=0.52-1.64). Studies reporting lower frailty prevalence showed stronger associations between frailty and mortality (beta=-0.009, P=0.03, R=49.6%), with the most consistent (PQ=0.11) associations found in studies using prospective measures (pooled RR=2.57, 95%CI=2.30-2.88) and little attenuation after adjustment for age, sex and comorbidity. Ordinal cut-points appeared to provide superior discrimination to dichotomous thresholds.

Conclusions

Frailty is common in older patients with acute, non-elective hospital admissions and remains an independent predictor of mortality, LOS and discharge home in the acute setting, justifying more widespread implementation of screening using prospective tools and consideration of the degree of frailty in guidance.

Age-related changes in lumbar bone mineral density measured using quantitative computed tomography in healthy female cynomolgus monkeys

Background

Cynomolgus monkeys are widely used in studies related to osteoporosis, and there is no evidence of age-related changes in volumetric bone mineral density (vBMD) measured using quantitative computed tomography (QCT) in nonhuman primates. This study aimed to describe changes in the characteristics of lumbar vBMD with age, to analyze the relationship between lumbar vBMD and body composition, and to investigate the precision of QCT measurements in healthy female cynomolgus monkeys.

Methods

Age-related changes in lumbar vBMD were described using cubic regression models, and the accumulated bone loss rates (ABLR) of the lumbar spine were calculated. Spearman rank correlation and ridge regression analysis were used to investigate the relationship of the average lumbar vBMD and body components. Thirty animals were selected to analyze the short-term in vivo precision of the QCT measurements. The precision was expressed as the root-mean-square coefficient of variation (RMS-CV%) or root-mean-square standard deviation (RMS-SD).

Results

A total of 72 healthy female cynomolgus monkeys, aged 1-25 years, were included in this study. The average lumbar vBMD of female cynomolgus monkeys increased with age until the age of 10 years, around which it reached peak bone mass, with a relatively marked decline after the age of 13 years. The ABLRs of female cynomolgus monkeys in the premenopausal (13-19 years) and postmenopausal age groups (20-25 years) were -4.9% and -21.2%, respectively. Ridge regression analysis showed that age and subcutaneous adipose tissue (SAT) contributed positively to the average lumbar vBMD in animals aged ≤10 years, whereas in animals aged >10 years, age contributed negatively to lumbar vBMD. The RMS-CV% (RMS-SD) of the lumbar vBMD measured using QCT ranged from 0.47% to 1.60% (1.91-6.31 mg/cm³).

Conclusions

Age-related changes in lumbar vBMD measured using QCT in healthy female monkeys showed similar trends to those in humans. Age and SAT may affect the lumbar vBMD in female cynomolgus monkeys. QCT revealed good precision in measuring the lumbar vBMD in female cynomolgus monkeys.

Erratum: Author Correction: Advancing COVID-19 diagnosis with privacy-preserving collaboration in artificial intelligence

[This corrects the article DOI: 10.1038/s42256-021-00421-z.].

Transcriptomic Mapping of Human Parotid Gland at Single-Cell Resolution

As the largest salivary gland in oral cavity, the parotid gland plays an important role in initial digesting and lubricating food. The abnormal secretory function of the parotid gland can lead to dental caries and oral mucosal inflammation. In recent years, single-cell RNA sequencing (scRNA-seq) has been used to explore the heterogeneity and diversity of cells in various organs and tissues. However, the transcription profile of the human parotid gland at single-cell resolution has not been reported yet. In this study, we constructed the cell atlas of human parotid gland using the 10× Genomics platform. Characteristic gene analysis identified the biological functions of serous acinar cell populations in secreting digestive enzymes and antibacterial proteins. We revealed the specificity and similarity of the parotid gland compared to other digestive glands through comparative analyses of other published scRNA-seq data sets. We also identified the cell-specific expression of hub genes for Sjögren syndrome in the human parotid gland by integrating the results of genome-wide association studies and bulk RNA-seq, which highlighted the importance of immune cell dysfunction in parotid Sjögren syndrome pathogenesis.

[The clinical efficacy of the stratification medical treatment based on the risk estimation of motor complications in Parkinson's disease]

Objectives: To evaluate the clinical efficacy of the stratification medical treatment based on the motor complications risk estimation in improving the quality of life, motor symptoms and delaying the motor complications in Parkinson's patients. Methods: Outpatients and inpatients from Xinhua Hospital, Shanghai Jiao Tong University, were recruited between November 2019 and June 2020. The participants were all clinically diagnosed with PD and treated with anti-PD medications, but had no history of motor complications, with the 8-item Parkinson's disease questionnaire summary index (PDQ-8 SI)>18.59. At baseline, the demographic characteristics, PD medical history, levodopa dosage (LD) and levodopa equivalent dosage (LED) were collected, and the evaluation of PDQ-8, Unified Parkinson's disease rating scale (UPDRS)-Ⅱ and Ⅲ, Hoehn and Yahr (H&Y) grade, Hamilton anxiety scale-14 (HAMA-14), Hamilton depression scale-24 (HAMD-24), mini-mental state examination (MMSE), Pittsburgh sleep quality index (PSQI), and Epworth sleepiness scale (ESS) tools was accomplished in all participants. Meanwhile, a Parkinson's disease risk estimation scale for motor complications was used to assess patients' risk of motor complications, and thus the medication was stratified in PD patients accordingly. During the 6-month and 12-month follow-ups, the evaluation of the above-mentioned parameters was repeated in all participants. At the 3-month and 9-month follow-ups, the information of anti-PD medications, the occurrence of motor complications (motor fluctuations and dyskinesia) and adverse drug reactions were recorded, and PDQ-8 was also evaluated. Results: Two hundred and fifty-one patients completed the 1-year follow-up, with 135 males and 116 females. At baseline, the median age of the patients was 66 (60, 71) years and the median PDQ-8 SI was 31.2 (21.9, 40.6). Additionally, 15.9% (40/251) of the patients were at high risk of motor fluctuation, and 7.2% (18/251) were at high risk of dyskinesia. There were significant differences in the age of onset, disease duration, PD treatment duration, the scores of UPDRS-Ⅱ and Ⅲ, H&Y Grade, and PDQ-8 SI among PD patients of different risk groups (all P<0.05). In the 12th month, the median of PDQ-8 SI, Δ PDQ-8 SI and Δ UPDRS-Ⅲ was 12.5 (9.4, 18.8), -15.6 (-21.9, -9.4) and -9(-16, -4), respectively, which was statistically different from that of baseline (all P<0.05). The change of UPDRS-Ⅱ scores in the group with high risk of motor fluctuation was statistically different from that in the groups with low and moderate risk (P<0.05). The changes of PSQI score, LD and LED in the group with high risk of dyskinesia was statistically different from those in the groups with low and moderate risk (all P<0.05). During the follow-up, the incidence of motor fluctuation and dyskinesia was 9.56% (24/251) and 5.97% (15/251), respectively. Conclusion: The stratification medical treatment might have a positive intervention effect on promoting a better quality of life, improving motor symptoms and delaying motor complications in PD patients.

Electroclinical and Multimodality Neuroimaging Characteristics and Predictors of Post-Surgical Outcome in Focal Cortical Dysplasia Type IIIa

Focal cortical dysplasia (FCD) type IIIa is an easily ignored cause of intractable temporal lobe epilepsy. This study aimed to analyze the clinical, electrophysiological, and imaging characteristics in FCD type IIIa and to search for predictors associated with postoperative outcome in order to identify potential candidates for epilepsy surgery. We performed a retrospective review including sixty-six patients with FCD type IIIa who underwent resection for drug-resistant epilepsy. We evaluated the clinical, electrophysiological, and neuroimaging features for potential association with seizure outcome. Univariate and multivariate analyses were conducted to explore their predictive role on the seizure outcome. We demonstrated that thirty-nine (59.1%) patients had seizure freedom outcomes (Engel class Ia) with a median postsurgical follow-up lasting 29.5 months. By univariate analysis, duration of epilepsy (less than 12 years) (p = 0.044), absence of contralateral insular lobe hypometabolism on PET/MRI (p_Log-rank = 0.025), and complete resection of epileptogenic area (p_Log-rank = 0.004) were associated with seizure outcome. The incomplete resection of the epileptogenic area (hazard ratio = 2.977, 95% CI 1.218–7.277, p = 0.017) was the only independent predictor for seizure recurrence after surgery by multivariate analysis. The results of past history, semiology, electrophysiological, and MRI were not associated with seizure outcomes. Carefully included patients with FCD type IIIa through a comprehensive evaluation of their clinical, electrophysiological, and neuroimaging characteristics can be good candidates for resection. Several preoperative factors appear to be predictive of the postoperative outcome and may help in optimizing the selection of ideal candidates to benefit from epilepsy surgery.

Localizing Epileptic Foci Before Surgery in Patients With MRI-Negative Refractory Epilepsy Using Statistical Parameter Mapping and Three-Dimensional Stereotactic Surface Projection Based on 18F-FDG PET

Patients with refractory epilepsy are not only free of seizures after resecting epileptic foci, but also experience significantly improved quality of life. Fluorine-18-fluorodeoxyglucose positron-emission tomography (18F-FDG PET) is a promising avenue for detecting epileptic foci in patients with magnetic resonance imaging (MRI)-negative refractory epilepsy. However, the detection of epileptic foci by visual assessment based on 18F-FDG PET is often complicated by a variety of factors in clinical practice. Easy imaging methods based on 18F-FDG PET images, such as statistical parameter mapping (SPM) and three-dimensional stereotactic surface projection (3D-SSP), can objectively detect epileptic foci. In this study, the regions of surgical resection of patients with over 1 year follow-up and no seizures were defined as standard epileptic foci. We retrospectively analyzed the sensitivity of visual assessment, SPM and 3D-SSP based on 18F-FDG PET to detect epileptic foci in MRI-negative refractory epilepsy patients and obtained the sensitivities of visual assessment, SPM and 3D-SSP are 57, 70 and 60% respectively. Visual assessment combined with SPM or 3D-SSP can improve the sensitivity of detecting epileptic foci. The sensitivity was highest when the three methods were combined, but decreased consistency, in localizing epileptic foci. We conclude that SPM and 3D-SSP can be used as objective methods to detect epileptic foci before surgery in patients with MRI-negative refractory epilepsy. Visual assessment is the preferred method for PET image analysis in MRI-negative refractory epilepsy. When the visual assessment is inconsistent with the patient's electroclinical information, SPM or 3D-SSP was further selected to assess the epileptic foci. If the combination of the two methods still fails to accurately locate the epileptic foci, comprehensive evaluation can be performed by combining the three methods.

Advancing COVID-19 diagnosis with privacy-preserving collaboration in artificial intelligence

Artificial intelligence provides a promising solution for streamlining COVID-19 diagnoses; however, concerns surrounding security and trustworthiness impede the collection of large-scale representative medical data, posing a considerable challenge for training a well-generalized model in clinical practices. To address this, we launch the Unified CT-COVID AI Diagnostic Initiative (UCADI), where the artificial intelligence (AI) model can be distributedly trained and independently executed at each host institution under a federated learning framework without data sharing. Here we show that our federated learning framework model considerably outperformed all of the local models (with a test sensitivity/specificity of 0.973/0.951 in China and 0.730/0.942 in the United Kingdom), achieving comparable performance with a panel of professional radiologists. We further evaluated the model on the hold-out (collected from another two hospitals without the federated learning framework) and heterogeneous (acquired with contrast materials) data, provided visual explanations for decisions made by the model, and analysed the trade-offs between the model performance and the communication costs in the federated training process. Our study is based on 9,573 chest computed tomography scans from 3,336 patients collected from 23 hospitals located in China and the United Kingdom. Collectively, our work advanced the prospects of utilizing federated learning for privacy-preserving AI in digital health.

Advancing COVID-19 Diagnosis with Privacy-Preserving Collaboration in Artificial Intelligence

Artificial intelligence (AI) provides a promising substitution for streamlining COVID-19 diagnoses. However, concerns surrounding security and trustworthiness impede the collection of large-scale representative medical data, posing a considerable challenge for training a well-generalised model in clinical practices. To address this, we launch the Unified CT-COVID AI Diagnostic Initiative (UCADI), where the AI model can be distributedly trained and independently executed at each host institution under a federated learning framework (FL) without data sharing. Here we show that our FL model outperformed all the local models by a large yield (test sensitivity /specificity in China: 0.973/0.951, in the UK: 0.730/0.942), achieving comparable performance with a panel of professional radiologists. We further evaluated the model on the hold-out (collected from another two hospitals leaving out the FL) and heterogeneous (acquired with contrast materials) data, provided visual explanations for decisions made by the model, and analysed the trade-offs between the model performance and the communication costs in the federated training process. Our study is based on 9,573 chest computed tomography scans (CTs) from 3,336 patients collected from 23 hospitals located in China and the UK. Collectively, our work advanced the prospects of utilising federated learning for privacy-preserving AI in digital health.

Positron Emission Tomography Imaging of the Endocannabinoid System: Opportunities and Challenges in Radiotracer Development

The endocannabinoid system (ECS) is involved in a wide range of biological functions and comprises cannabinoid receptors and enzymes responsible for endocannabinoid synthesis and degradation. Over the past 2 decades, significant advances toward developing drugs and positron emission tomography (PET) tracers targeting different components of the ECS have been made. Herein, we summarized the recent development of PET tracers for imaging cannabinoid receptors 1 (CB1R) and 2 (CB2R) as well as the key enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), particularly focusing on PET neuroimaging applications. State-of-the-art PET tracers for the ECS will be reviewed including their chemical design, pharmacological properties, radiolabeling, as well as preclinical and human PET imaging. In addition, this review addresses the current challenges for ECS PET biomarker development and highlights the important role of PET ligands to study disease pathophysiology as well as to facilitate drug discovery.

Synthesis and preliminary evaluation of a novel positron emission tomography (PET) ligand for imaging fatty acid amide hydrolase (FAAH)

Fatty acid amide hydrolase (FAAH) exerts its main function in the catabolism of the endogenous chemical messenger anandamide (AEA), thus modulating the endocannabinoid (eCB) pathway. Inhibition of FAAH may serve as an effective strategy to relieve anxiety and possibly other central nervous system (CNS)-related disorders. Positron emission tomography (PET) would facilitate us to better understand the relationship between FAAH in certain disease conditions, and accelerate clinical translation of FAAH inhibitors by providing in vivo quantitative information. So far, most PET tracers show irreversible binding patterns with FAAH, which would result in complicated quantitative processes. Herein, we have identified a new FAAH inhibitor (1-((1-methyl-1H-indol-2-yl)methyl)piperidin-4-yl)(oxazol-2-yl)methanone (8) which inhibits the hydrolysis of AEA in the brain with high potency (IC₅₀ value 11 nM at a substrate concentration of 0.5 µM), and without showing time-dependency. The PET tracer [¹¹C]8 (also called [¹¹C]FAAH-1906) was successfully radiolabeled with [¹¹C]MeI in 17 ± 6% decay-corrected radiochemical yield (n = 7) with >74.0 GBq/μmol (2 Ci/μmol) molar activity and >99% radiochemical purity. Ex vivo biodistribution and blocking studies of [¹¹C]8 in normal mice were also conducted, indicating good brain penetration, high brain target selectivity, and modest to excellent target selectivity in peripheral tissues. Thus, [¹¹C]8 is a potentially useful PET ligand with enzyme inhibitory and target binding properties consistent with a reversible mode of action.

Bioremediation of PAH-contaminated shooting range soil using integrated approaches

Serious contamination of polycyclic aromatic hydrocarbons (PAHs) occurs at outdoor shooting ranges due to the accumulation of clay target fragments containing coal tar or petroleum pitch. These contaminated sites are characterized with high-molecular-weight PAHs that are low in bioavailability and recalcitrant to bioremediation. We evaluated the effectiveness of different remediation strategies, used individually or in combinations, to decontaminate PAHs in a shooting range soil. The treatments included vegetation with bermudagrass [Cynodon dactylon (L.) Pers] or switchgrass [Panicum virgatum]), bioaugmentation of Mycobacterium vanbaalenii PYR-1, and addition of surfactants (Brij-35, rhamnolipid biosurfactant, or Brij-35/sodium dodecyl sulfate mixture). The initial total PAH concentration in the shooting range soil was 373 mg/kg and consisted of primarily high-molecular-weight PAHs (84%). Planting of bermudagrass and switchgrass resulted in 36% and 27% ∑₁₆PAH reduction compared to the non-vegetated control, respectively. Bermudagrass enhanced soil dehydrogenase activity and both vegetation treatments also increased polyphenol oxidase activity. Bioaugmentation of M. vanbaalenii PYR-1 had a significant effect only on the dissipation of high-molecular-weight PAHs, leading to a 15% decrease (∑₁₀PAH) compared to the control. In the non-vegetated soil, Brij-35/sodium dodecyl sulfate mixture increased PAH degradation compared to the no surfactant control. The increased PAH biodegradation in the vegetated and bioaugmented treatments improved lettuce [Lactuca sativa] seed germination, suggesting reduced toxicity in the treated soils. Phytoremediation using bermudagrass or switchgrass with bioaugmentation of M. vanbaalenii PYR-1 was an effective in situ remediation option for shooting range soils with heavy PAH contamination.

A collaborative online AI engine for CT-based COVID-19 diagnosis

Artificial intelligence can potentially provide a substantial role in streamlining chest computed tomography (CT) diagnosis of COVID-19 patients. However, several critical hurdles have impeded the development of robust AI model, which include deficiency, isolation, and heterogeneity of CT data generated from diverse institutions. These bring about lack of generalization of AI model and therefore prevent it from applications in clinical practices. To overcome this, we proposed a federated learning-based Unified CT-COVID AI Diagnostic Initiative (UCADI, http://www.ai-ct-covid.team/), a decentralized architecture where the AI model is distributed to and executed at each host institution with the data sources or client ends for training and inferencing without sharing individual patient data. Specifically, we firstly developed an initial AI CT model based on data collected from three Tongji hospitals in Wuhan. After model evaluation, we found that the initial model can identify COVID from Tongji CT test data at near radiologist-level (97.5% sensitivity) but performed worse when it was tested on COVID cases from Wuhan Union Hospital (72% sensitivity), indicating a lack of model generalization. Next, we used the publicly available UCADI framework to build a federated model which integrated COVID CT cases from the Tongji hospitals and Wuhan Union hospital (WU) without transferring the WU data. The federated model not only performed similarly on Tongji test data but improved the detection sensitivity (98%) on WU test cases. The UCADI framework will allow participants worldwide to use and contribute to the model, to deliver a real-world, globally built and validated clinic CT-COVID AI tool. This effort directly supports the United Nations Sustainable Development Goals' number 3, Good Health and Well-Being, and allows sharing and transferring of knowledge to fight this devastating disease around the world.

Soil bacterial community dynamics following surfactant addition and bioaugmentation in pyrene-contaminated soils

Because of their toxic properties, polycyclic aromatic hydrocarbons (PAHs) are designated as priority pollutants. The low solubility and strong sorption of PAHs in soil often limits bioremediation. To increase PAH bioavailability and enhance microbial degradation, surfactants are often added to contaminated soils. However, the effects of surfactants on the PAH degradation capacities of soil microbes are generally neglected. In this study, 16S rRNA gene high-throughput sequencing was used to evaluate changes in the soil microbial community after the application of rhamnolipid biosurfactant or Brij-35 surfactant and Mycobacterium vanbaalenii PYR-1 bioaugmentation over a 50-d mineralization study in two soils contaminated with pyrene at 10 mg kg^-1. The introduction of pyrene in both soils resulted in an increase in Firmicutes and a decrease in microbial richness and Shannon diversity index. Amendment of rhamnolipid at 1,400 μg g^-1 to the native clay soil resulted in a decrease in Bacillus from 48% to 2%, which was accompanied with an increase in Mycoplana that accounted for 67% of the total genera relative abundance. Phylogenetic investigation of communities by reconstruction of unobserved states was used to predict the activity of functional genes involved in the PAH degradation KEGG pathway and determined that M. vanbaalenii PYR-1 bioaugmentation resulted in an increased number of functional genes utilized in PAH biodegradation. Results of this study provide a better understanding of the soil microbial dynamics in response to surfactant amendments in addition to bioaugmentation of a PAH-degrading microbe. This knowledge contributes to successful and efficient surfactant-enhanced bioremediation of PAH-contaminated soils.

Irradiation-Dependent Helium Gas Bubble Superlattice in Tungsten

The implantation of noble gas atoms into metals at high gas concentrations can lead to the self-organization of nanobubbles into superlattices with symmetry similar to the metal host matrix. Here, we examine the influence of implantation parameters on the formation and structure of helium gas bubble superlattices within a tungsten host matrix to uncover mechanistic insight into the formation process. The determination of the size and symmetry of the gas bubbles was performed using a combination of small angle x-ray scattering and transmission electron microscopy. The former was demonstrated to be particularly useful in determining size and structure of the gas bubble superlattice as a function of irradiation conditions. Prior to the formation of a superlattice, we observe a persistent substructure characterized by inter-bubble spacings similar to those observable when the gas bubble superlattice has formed with very large ordering parameters. As the implantation fluence increases, the inter-bubble ordering parameter decreases, indicating improved ordering, until a superlattice is formed. Multiple implantation-specific differences were observed, including a temperature-dependent superlattice parameter that increases with increasing temperature and a flux-dependent superlattice parameter that decreases with increasing flux. The trends quantified here are in excellent agreement with our recent theoretical predictions for gas bubble superlattice formation and highlight that superlattice formation is strongly dependent on the diffusion of vacancy and implanted He atoms.

Abstract P6-17-39: BAT8001, a potent anti-HER2 antibody-drug conjugate with a novel stable linker for the treatment of HER2-positive breast cancer

Overexpression of HER2 occurs in approximately 20% of breast cancers and is associated with shortened survival. Trastuzumab emtansine (T-DM1), an anti-HER2 ADC, has shown efficacy in HER2-positive breast cancer patients and was approved by the FDA and EMA for advanced HER2-positive breast cancer. However T-DM1 causes grade 3 and 4 thrombocytopenia in up to 14.5% of patients as its major toxicity. The thrombocytopenia is likely caused by one of T-DM1's catabolites and payload, DM1, indicating T-DM1's linker can be cleaved. Here we adopted a novel noncleavable linker and created an anti-HER2 ADC, BAT8001, which is expected be efficacious in HER2-positive breast cancer and have a better side effect profile relative to T-DM1 due to the stability of BAT8001's noncleavable linker. BAT8001 is internalized in HER2-positive cancer cells. It inhibits proliferation of HER2-positive tumor cells with IC50s of ˜0.1 nM, similar to the potency of T-DM1. BAT8001 also induces apoptosis in HER2-positive cancer cells. In both cell-line and patient-derived mouse xenograft (PDX) models, BAT8001 demonstrates strong inhibition activity on tumor growth. For example, in a cell-line model of breast cancer (BT474), BAT8001 demonstrates potent activity with complete responses in all animals tested at the 15mg/kg dose level. Pharmacokinetics studies in monkey reveals BAT8001 has similar Cmax, AUC, and t1/2 as T-DM1. The major catabolite of BAT8001 is the Cys-linker-payload containing product. No free payload is observed. This compares favorably with T-DM1 where free DM1, T-DM1's payload, is one of the major catabolites. In a multiple dose toxicity study, BAT8001 had a NOAEL of 15 mg/kg versus 10 mg/kg for T-DM1. BAT8001 exhibits similar potency to T-DM1 on inhibiting HER2-positive cell proliferation and tumor growth, yet demonstrates better multiple dose toxicity than T-DM1. The improved toxicity profile of BAT8001 suggests that the novel noncleavable linker utilized in BAT8001 is more stable than the linker utilized in T-DM1. BAT8001 is very efficacious in cell-line xenograft models of breast cancer. The preclinical profile of BAT8001 warrants further development for the treatment of breast cancer and other HER2-positive cancers.

Citation Format: Tang W, Deng X, Ou Z, Gan J, Dong Q, Tan B, Lu L, Chen B, Bao C, Li S, Thomas B, Yu J-C. BAT8001, a potent anti-HER2 antibody-drug conjugate with a novel stable linker for the treatment of HER2-positive breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-39.

Influence of rhamnolipid biosurfactant and Brij-35 synthetic surfactant on 14C-Pyrene mineralization in soil

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in soil and are considered priority pollutants due to their carcinogenicity. Bioremediation of PAH-contaminated soils is often limited by the low solubility and strong sorption of PAHs in soil. Synthetic surfactants and biosurfactants have been used to enhance the bioavailability of PAHs and to accelerate microbial degradation. However, few studies have compared synthetic and biosurfactants in their efficiency in promoting PAH biodegradation in either native or bioaugmented soils. In this study, we evaluated mineralization of ¹⁴C-pyrene in soils with or without the augmentation of Mycobacterium vanbaalenii PYR-1, and characterized the effect of Brij-35 (synthetic) and rhamnolipid biosurfactant at different amendment rates. Treatment of rhamnolipid biosurfactant at 140 or 1400 μg surfactant g-dry soil^-1 rates resulted in a significantly longer lag period in ¹⁴C-pyrene mineralization in both native and bioaugmented soils. In contrast, amendment of Brij-35 generally increased ¹⁴C-pyrene degradation, and the greatest enhancement occurred at 21.6 or 216 μg surfactant g-dry soil^-1 rates, which may be attributed to increased bioavailability. Brij-35 and rhamnolipid biosurfactant were found to be non-toxic to M. vanbaalenii PYR-1 at 10X CMC, thus indicating rhamnolipid biosurfactant likely served as a preferential carbon source to the degrading bacteria in place of ¹⁴C-pyrene, leading to delayed and inhibited ¹⁴C-pyrene degradation. Mineralization of ¹⁴C-pyrene by M. vanbaalenii PYR-1 was rapid in the unamended soils, and up to 60% of pyrene was mineralized to ¹⁴CO₂ after 10 d in the unamended or Brij-35 surfactant-amended soils. Findings of this study suggest that application of surfactants may not always lead to enhanced PAH biodegradation or removal. If the surfactant is preferentially used as an easier carbon substrate than PAHs for soil microorganisms, it may actually inhibit PAH biodegradation. Selection of surfactant types is therefore crucial for the effectiveness of surfactant-aided bioremediation of PAH-contaminated soils.

Effect of Nd:YAG Laser Irradiation Pretreatment on the Long-Term Bond Strength of Etch-and-Rinse Adhesive to Dentin

PURPOSE

To investigate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation pretreatment on the long-term bond strength of an etch-and-rinse adhesive to dentin.

METHODS

Fifty molars were sectioned parallel to the occlusal plane and randomly divided into two groups (n=25 per group): control group (no treatment) and laser group (dentin surfaces were treated with Nd:YAG laser at a setting of 100 mJ/10 Hz). Afterward, resin was bonded to the dentin surface using a two-step etch-and-rinse adhesive (Adper SingleBond 2), and then 150 beams of each group were produced. Each group was divided into three subgroups (n=50 each group): 24 hours of water storage, thermocycling, and NaOCl storage. The microtensile bond strength (MTBS), failure modes, nanoleakage expression, and Masson's trichrome staining were evaluated. An additional 20 molars were sectioned to obtain 2-mm-thick flat dentin slices. These slices were randomly divided into control and laser-treated groups as mentioned previously. Then slices of each group were examined by scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and the Knoop hardness test.

RESULTS

The results of ATR-FTIR and Masson's trichrome verified that laser irradiation partly removed collagen fibers from the dentin surface; however, no significant difference was found in the Knoop hardness (p>0.05). The XRD result showed similar crystalline structure regardless of laser pretreatment. There is no significant difference in short-term MTBS between control and laser-treated groups (p>0.05); however, long-term MTBS differed between the groups (p>0.05). Furthermore, the laser-treated group showed less silver deposition than the control group after aging (p<0.05).

CONCLUSION

Pretreatment by Nd:YAG laser irradiation appeared to have a positive effect on the adhesive-dentin bonding in vitro test, and the bonding effectiveness could be preserved after aging.

Stable actively Q-switched single-frequency fiber laser at 1.5 μm based on self-injecting polarization modulation

A new technique for the realization of a stable Q-switched operation in a single-frequency fiber laser based on self-injecting polarization modulation is demonstrated, for the first time to the best of our knowledge. A piezoelectric fiber stretcher was utilized to introduce periodic stress-induced polarization changes. Then the modulation of polarization state transformed into Q switching by virtue of a designed distributed Bragg reflector (DBR) resonant cavity with polarizations loss anisotropy. Finally, a stable actively Q-switched single-frequency fiber laser at 1.5 μm with Gaussian-shape pulse output was achieved. We experimentally found that, the repetition frequency (several hundred kHz) coincided with the working frequency of the polarization modulation, and the pulse width (several hundred ns) reduced with the increasing of the modulating frequency, the modulating amplitude, as well as the pump power. This stable Q-switched single-frequency fiber laser is promising for applications in optical time-domain reflectometry, coherent Doppler wind radar, and optical coherent detection. More importantly, this novel Q-switched technology may be applicable to other DBR single-frequency fiber lasers.

GSK2878175, a pan-genotypic non-nucleoside NS5B polymerase inhibitor, in healthy and treatment-naïve chronic hepatitis C subjects

GSK2878175 is a potent, pan-genotypic, non-nucleoside, nonstructural protein 5B palm polymerase inhibitor being developed for the treatment of chronic hepatitis C (CHC). A first-in-human, randomized, placebo-controlled, dose escalation study, evaluated the safety and pharmacokinetics of GSK2878175 administered as single and repeat oral doses (once daily for 14 days) to healthy volunteers. A separate proof-of-concept, placebo-controlled, repeat dose (once daily for 2 days) study evaluated the safety, pharmacokinetics and antiviral activity of GSK2878175 monotherapy in treatment-naïve, noncirrhotic, subjects with hepatitis C virus (HCV) genotype 1 [1a and 1b], 2, or 3. No deaths or SAEs were reported in either study, and treatment was well-tolerated. Across all the HCV genotypes, GSK2878175 monotherapy at doses of 10, 30 or 60 mg once daily for 2 days produced a statistically significant multilog reduction (P<.001) in plasma HCV RNA log₁₀ IU/mL from Baseline to 24, 48 and 72 hours after the first dose of GSK2878175 compared to placebo. The reduction in HCV RNA was sustained for a prolonged period across all of the active treatment groups, consistent with the long apparent half-life of GSK2878175 that was observed (mean t_1/2 range: 60-63 hours in the CHC subjects). In summary, GSK2878175, when administered to healthy subjects and subjects with CHC, did not reveal any safety concerns that would limit or preclude further clinical development. GSK2878175 monotherapy across a wide dose range produced substantial reduction in HCV RNA, irrespective of HCV genotype. The results from these studies support further evaluation of GSK2878175-based regimens.

Interface phenomena in magnetron sputtered Cu2O/ZnO heterostructures

The interface between ZnO and Cu₂O has been predicted to be a good candidate for use in thin film solar cells. However, the high predicted conversion efficiency has yet to be fully realized experimentally. To explore the underlying causes of this we investigate the interface between ZnO and Cu₂O in magnetron sputtered samples. Two different sample geometries were made: In the first set thin layers of ZnO were deposited on Cu₂O (type A), while in the second set the order was reversed (type B). Using x-ray photoelectron spectroscopy (XPS), an intermediate CuO layer was identified regardless of the order in which the Cu₂O and ZnO layers were deposited. The presence of a CuO layer was supported by transmission electron microscopy (TEM) results. Changes in the electron hole screening conditions were observed in CuO near the interface with ZnO, manifested as changes in the relative peak-to-satellite ratio and the degree of asymmetric broadness in the Cu 2p peak. The suppression of the Cu 2p satellite characteristic of CuO may cause the CuO presence to be overlooked and cause errors in determinations of valence band offsets (VBOs). For the type A samples, we compare four different approaches to XPS-based determination of VBO and find that the most reliable results are obtained when the thin CuO layer and the altered screening conditions at the interface were taken into account. The VBOs were found to range between 2.5 eV and 2.8 eV. For the B type samples a reduction of the Cu 2p-LMM Auger parameter was found as compared to bulk Cu₂O, indicative of quantum confinement in the Cu₂O overlayer.

[Effect of a nano hydroxyapatite desensitizing paste application on dentin bond strength of three self-etch adhesive systems]

Objective: To evaluate a nano-hydroxyapatite (nano-HA) desensitizing paste application on the bond strength of three self-etch adhesives. Methods: Three dentin specimens of about 1 mm thick were cut from two teeth. Scanning electron microscope (SEM) was used to evaluate the dentin surfaces without treatment, after citric acid treatment and after nano-HA treatment. Thirty-six intact third molars extracted for surgical reasons were cut to remove the occlusal enamel with isomet, and then were etched with 1% citric acid for 20 s to simulate the sensitive dentin and divided into two groups randomly using a table of random numbers (n=18): the control group (no treatment) and the HA treated group (with nano-HA paste treatment). Each group was divided into three subgroups randomly using a table of random numbers (n=6). Subgroup A, B and C was bonded with G-Bond, Clearfil S(3) Bond and FL-Bond Ⅱ according to the manufacture's instruction separately. At 24 h after bonding procedure, and after water storage for 6 months, microtensile bond strength of the specimens was tested and the failure mode was analyzed. Results: SEM obeservation showed that citric acid could open the dentin tubules to set up the sensitive dentin model, and the nano-HA could occlude the dentin tubules effectively. For subgroup A, bonding strength of specimens treated with nano-HA ([41.14±8.91] MPa) was significantly high than that of the control group ([34.27±6.16] MPa) at 24 h after bonding procedure (P<0.05). However, after 6 month water ageing, the bonding strength of the control group and the HA treated group showed no significant difference (P>0.05). For subgroup B, specimens with nano-HA application showed lower bonding strength ([30.87±6.41] MPa) than that of the control group ([36.73±5.82] MPa) at 24 h after bonding procedure (P<0.05), and after 6 month water ageing, the bond strength of nano-HA application ([25.73±6.99] MPa) was also lower than that of the control group ([32.33±5.08] MPa) (P<0.05). For subgroup C, the bond strength of the control group and the HA treated group have no significant difference either before or after 6 month water ageing (P>0.05). Failure mode analysis showed that more than half of the samples in all groups were adhesive failure. Conclusions: Nano-HA treatment decreased the bond strength of subgroup B, while had no adverse effect on subgroup A and subgroup C.

[Perioperative management and surgical treatment of neurosurgical critical patients with thrombocytopenia]

OBJECTIVE

To study the perioperative management and surgical treatment of patients with neurosurgical critical diseases and thrombocytopenia.

METHODS

Eleven patients with the diagnosis of neurosurgical critical diseases and thrombocytopenia who received surgical treatment in Department of Neurosurgery, Peking Union Medical College Hospital from 2010 to 2015 were reviewed retrospectively. All eleven patients received platelet transfusions preoperatively. The safety and efficacy of surgical treatment were analyzed by GOS score at 6 months after operations.

RESULTS

Platelet counts of six patients who received minimally invasive surgery reached 80×10(9) /L by platelet transfusions preoperatively. Platelet counts of five patients who received Craniotomy and ventriculoperitoneal shunt reached 100×10(9) /L by platelet transfusions preoperatively. Eight patients received platelet transfusions postoperatively according to a low platelet count 24 hours after operations. Two patients died after surgery and one died after discharge. All other eight survival patients got well recovery with an average GOS score of 4.5 at six months after operations.

CONCLUSIONS

Patients with neurosurgical critical diseases and thrombocytopenia could receive surgical treatment in collaboration with relative departments.

PTPRO represses ERBB2-driven breast oncogenesis by dephosphorylation and endosomal internalization of ERBB2

The plasma membrane-associated tyrosine phosphatase PTPRO is frequently transcriptionally repressed in cancers and signifies poor prognosis of breast cancer patients. In this study, deletion of Ptpro in MMTV-Erbb2 transgenic mice dramatically shortened the mammary tumor latency and accelerated tumor growth due to loss of Ptpro within the breast cancer cells but not in surrounding tissue as confirmed by hetero-transplantation studies. Both in vitro and in vivo data demonstrated that the phosphatase activity was required for the inactivation of ERBB2 and its downstream signaling. PTPRO regulated the phosphorylation status of ERBB2 at Y1248. Co-immunoprecipitation and proximity ligation assay (Duolink) indicated that PTPRO directly physically interacted with ERBB2. Moreover, PTPRO phosphatase activity shortened the half-life of ERBB2 by increasing endocytotic degradation. PTPRO reexpression by demethylation treatment using 5-azacytidine reduced the proliferation and colony formation potential in ERBB2-positive breast cancer cells. Taken together, PTPRO inhibited ERBB2-driven breast cancer through dephosphorylation leading to dual effects of ERBB2 signaling suppression and endosomal internalization of ERBB2, Therefore, reexpression of PTPRO may be a potential therapy for ERBB2-overexpressing breast cancer.

Abnormal white matter structural connectivity in treatment-naïve young adults with borderline personality disorder

OBJECTIVE

The pathogenesis of borderline personality disorder (BPD) is not well understood. We examined the microstructure of white matter in patients with BPD.

METHOD

Treatment-naïve young adult with BPD (N = 30) and young-adult healthy controls (HCs; N = 31) were subjected diffusion tensor imaging (DTI). Microstructural parameters were analyzed via tract-based spatial statistics (TBSS) and post hoc tractography.

RESULTS

TBSS analysis revealed that, relative to the HC group, the BPD group had significantly lower fractional anisotropy (FA) values in the genu and body of the corpus callosum (CC), right superior corona radiate, right anterior corona radiate, as well as higher radial diffusivity (RD) in the left anterior thalamic radiation. Tractography showed that FA values of fiber bundles passing through the fornix were significantly reduced in BPD group relative to HCs. No significant correlations were observed between clinical symptom and DTI indices in BPD group (FDR corrected).

CONCLUSION

Focal microstructural alterations were found in BPD group, mainly in the limbic system and CC. The present findings support the fronto-limbic disconnectivity hypothesis and suggest that abnormal maturation of white matter structures may play an important role in mechanism of BPD.

Comparison of pollutant concentrations from weekly discrete versus composite samples for residential dry-weather runoff

As urbanization has increased, so has degradation of urban streams. Urban water quality monitoring has focused on storm runoff sampling, but in arid climates, dry-weather runoff is a significant contributor of pollutants to aquatic systems. The majority of dry-weather runoff studies sample a small window of the entire dry-season. For this study constituent concentrations were compared using two sampling protocols. The first protocol repeatedly collected samples on the same day of the week at the same time of day. The second protocol collected samples during two week-long intensive sampling events consisting of sample collection every hour for 24 h for seven consecutive days. The two protocols were compared to determine if sampling at the same time of the week was representative of the entire week. For nitrate, total phosphorous, fipronil, permethrin, total organic carbon, and total suspended solids, sampling at the same time was not representative of the weekly mean; however, variability was observed between sites and constituents. For those constituent concentrations with significant differences seen between the two protocols, load adjustment factors (LAF) were determined, using a ratio of treatment means, and employed to adjust dry-season load estimates. Future work should include determining if LAF values can be used at similar sites excluded from the study or for similar constituents from the current sampling sites.

[Effects of exogenous enzymes on the degradation of adhesive-dentin interfaces]

OBJECTIVE

To compare the effects of exogenous enzymes on the degradation of adhesive-dentin interface.

METHODS

Forty molars were sectioned to expose the middle-coronal dentin surface and randomly divided into two adhesive systems: an etch-and-rinse adhesive Adper Single Bond 2 and a self-etching adhesive G-Bond. After composite building up, the specimens were then randomly assigned to four groups(n=5 for each group)as follows: group 1, 24 h of water storage(the control group); group 2, six months of water storage; group 3, twelve weeks storage in artificial saliva containing clostridium histolyticum collagenase; group 4, twelve weeks storage in artificial saliva containing cholesterolesterase. The microtensile bond strengths(MTBS)were then tested. The failure modes and nanoleakage were analyzed.

RESULTS

After aging treatments, the three aging groups showed significantly lower MTBS compared with the control group in both adhesive systems(P<0.05). For etch-and-rinse adhesive Adper Single Bond 2, the MTBS of group 3([19.6±3.5]MPa)was lower than that of group 2([23.4±4.2]MPa)and group 4([24.2±4.2]MPa)(P<0.05). For self-etching adhesive G-Bond, there was no difference on MTBS among different aging groups(P>0.05). SEM observation showed that, compared with the control group, water storage(group 2)and the exogenous enzymes(group 3 and 4)increased the nanoleakage expression(silver deposition)of both adhesive systems. Adhesive failure was the predominant fracture modes in all groups.

CONCLUSIONS

Storage in artificial saliva containing clostridium histolyticum collagenase or cholesterol esterase could be used to accelerate the degradation process of adhesive-dentine interface.

Integration of Physiologically-Based Pharmacokinetic Modeling into Early Clinical Development: An Investigation of the Pharmacokinetic Nonlinearity

BMS-911543, a promising anticancer agent, exhibited time-dependent and dose-dependent nonlinear pharmacokinetics (PKs) in its first-in-human (FIH) study. Initial physiologically based pharmacokinetic (PBPK) modeling efforts using CYP1A2-mediated clearance kinetics were unsuccessful; however, further model analysis revealed that CYP1A2 time-dependent inhibition (TDI) and perhaps other factors could be keys to the nonlinearity. Subsequent experiments in human liver microsomes showed that the compound was a time-dependent inhibitor of CYP1A2 and were used to determine the enzyme inactivation parameter values. In addition, a rat tissue distribution study was conducted and human plasma samples were profiled to support the refinement of the PBPK model. It was concluded that the interplay between four BMS-911543 properties, namely, low solubility, saturation of the metabolizing enzyme CYP1A2, CYP1A2 TDI, and CYP1A2 induction likely resulted in the time-dependent and dose-dependent nonlinear PKs. The methodology of PBPK model-guided unmasking of compound properties can serve as a general practice for mechanistic understanding of a new compound's disposition.

Health and production traits in bovine are associated with single nucleotide polymorphisms in the NOD2 gene

The NOD2 gene plays a fundamental role in initiating the inflammatory and subsequent immune response. NOD2 was previously identified as a susceptibility locus for inflammatory bowel diseases in humans. In this study, we detected 2 mutations in exon 12 (A→T, G→A) among 5 cattle breeds (N = 315) and analyzed their associations with production traits and genetic resistance against bovine mastitis in Chinese Holstein and Chinese Simmental breeds (N = 218). The transitions (A→T) at position 114 bp were associated with somatic cell score (P < 0.01). The G→A at position 1594 bp plays a critical role in increasing 305-day milk yields. In Chinese Holstein and Chinese Simmental breeds, the BB genotype may contribute to disease susceptibility. Compared to all genotypic combinations, the A, B, and FF genotypes are beneficial not only for reducing somatic cell score but also for increasing production.