Node-Aligned Graph-to-Graph: Elevating Template-free Deep Learning Approaches in Single-Step Retrosynthesis

Single-step retrosynthesis in organic chemistry increasingly benefits from deep learning (DL) techniques in computer-aided synthesis design. While template-free DL models are flexible and promising for retrosynthesis prediction, they often ignore vital 2D molecular information and struggle with atom alignment for node generation, resulting in lower performance compared to the template-based and semi-template-based methods. To address these issues, we introduce node-aligned graph-to-graph (NAG2G), a transformer-based template-free DL model. NAG2G combines 2D molecular graphs and 3D conformations to retain comprehensive molecular details and incorporates product-reactant atom mapping through node alignment, which determines the order of the node-by-node graph outputs process in an autoregressive manner. Through rigorous benchmarking and detailed case studies, we have demonstrated that NAG2G stands out with its remarkable predictive accuracy on the expansive data sets of USPTO-50k and USPTO-FULL. Moreover, the model's practical utility is underscored by its successful prediction of synthesis pathways for multiple drug candidate molecules. This proves not only NAG2G's robustness but also its potential to revolutionize the prediction of complex chemical synthesis processes for future synthetic route design tasks.

Feasibility and safety of specimen extraction via an enlarged (U-Plus) skin bridge loop ileostomy: a single-center retrospective comparative study

Objective

To investigate the feasibility and safety of specimen extraction via an enlarged (U-Plus) skin bridge loop ileostomy.

Methods

A retrospective analysis of 95 patients with rectal cancer who underwent laparoscopic low anterior rectal resection and skin bridge loop ileostomy between August 2018 and August 2022, including 44 patients with specimen extraction via an enlarged (U-Plus) skin bridge loop ileostomy (experimental group) and 51 patients with specimen extraction via an abdominal incision (control group). Following the application of propensity score matching (PSM), 34 pairs of data were successfully matched. Subsequently, a comparative analysis was conducted on the clinical data of the two groups.

Results

The experimental group exhibited significantly better outcomes than the control group in various aspects. Specifically, the experimental group had lower values for average operative time (P < 0.001), estimated blood loss (P < 0.001), median length of visible incision after surgery (P < 0.001), median VAS pain score on the first day after surgery (P = 0.015), and average postoperative hospitalization (P = 0.001). There was no statistical significance observed in the incidence of stoma-related complications in both groups (P > 0.05). Within each group, the stoma-QOL scores before stoma closure surgery were significantly higher than those at one month and two months after the surgery, with statistical significance (P < 0.05).

Conclusion

Specimen extraction via a U-Plus skin bridge loop ileostomy is a safe and feasible method that shortens operation time and postoperative visual incision length, decreases estimated blood loss, and reduces patient postoperative pain compared with specimen extraction via an abdominal incision.

[Radiomics-based prediction of microsatellite instability in stage Ⅱ and Ⅲ rectal cancer patients based on T2WI MRI and diffusion-weighted imaging]

Objective: To examine the radiomics model based on high-resolution T2WI and diffusion weighted imaging (DWI) in predicting microsatellite stability in patients with stage Ⅱ and Ⅲ rectal cancer. Methods: From February 2016 to October 2020, 175 patients with stage Ⅱ and Ⅲ rectal cancer who met the inclusion criteria were retrospectively collected. There were 119 males and 56 females, aged (63.9±9.4) years (range: 37 to 85 years), including 152 patients with microsatellite stability and 23 patients with microsatellite instability. All patients were randomly divided into the training group (n=123) and the validation group (n=52) with a ratio of 7∶3. The region of interest was labeled on the T2WI and DWI images of each patient using the ITK-SNAP software, and PyRadiomics was used to extract seven kinds of radiomics features. After removing redundant features and normalizing features, the least absolute shrinkage and selection operation were used for feature selection. One clinical model, three radiomics models and one clinical-radiomics model were constructed in the training group based on a support vector machine. The area under receiver operating characteristic curve (AUC), sensitivity, specificity, and accuracy were used to evaluate the performance of the models in the verification group. Results: Three clinical features (age, degree of tumor differentiation, and distance from the lower edge of the tumor to the anal edge) and six radiomics features (two DWI-related features and four T2WI-related features) most related to microsatellite status of rectal cancer patients were selected. The AUC of the clinical-radiomics model in the training group was 0.95. In the validation group, the AUC was 0.81, better than the clinical model (0.68, Z=0.71, P=0.04), and equivalent to the T2WI+DWI model (0.82, Z=0.21, P=0.83). Conclusions: Radiomic features based on preoperative T2WI and DWI were related to microsatellite stability in patients with stage Ⅱ and Ⅲ rectal cancer and showed a high classification efficiency. The model based on the features provided a noninvasive and convenient tool for preoperative determination of microsatellite stability in rectal cancer patients.

Application of laparoscopic modified Bacon operation in patients with low rectal cancer and analysis of the changes in anal function: A retrospective single-center study

Purpose

To investigate the value of modified Bacon operation in patients with low rectal cancer.

Methods

Retrospective analysis of 60 patients treated with laparoscopic surgery for low rectal cancer in the Department of Colorectal and Anal Surgery, Jingzhou Hospital affiliated to Yangtze University, from 2019 to 2022, divided into observation and control groups based on the method of the operation (laparoscopic modified Bacon operation group and laparoscopic Dixon operation with prophylactic ileostomy group). We compared the variations between the two groups.

Results

The length of the abdominal surgical incision was shorter in the observation group than in the control group(P<0.05). In the observation group, the length of hospital stay after the first operation was shorter(P<0.05), the both operations time and the second intraoperative bleeding were less(P<0.05), the DET score at one week after the first operation and the VAS after both operations were fewer than in the control group(P<0.05), the postoperative rate of ischemic necrosis of the exposed bowel was higher(P<0.05), and the anal function was poorer in the short term after the second operation compared with the control group(P<0.05), but there was no significant difference between the anal function at 6 months after the second operation compared with the control group(P>0.05).12 months after the second operation, the anal function has recovered to the preoperative level in the observation group(P>0.05).

Conclusion

The laparoscopic modified Bacon operation has smaller abdominal wounds, which reduces postoperative pain; it does not require the use of staplers, which reduces the patient's financial burden; no postoperative anastomotic leakage occurs, and a more satisfactory anal function can be obtained.

Increased Dietary Niacin Intake Improves Muscle Strength, Quality, and Glucose Homeostasis in Adults over 40 Years of Age

BACKGROUND AND AIMS

Age-related loss of skeletal muscle mass and strength begins at 40 years of age, and limited evidence suggests that niacin supplementation increases levels of nicotinamide adenine dinucleotide in mouse muscle tissue. In addition, skeletal muscle has a key role in the body's processing of glucose. Therefore, this study aimed to investigate the relationship between dietary niacin and skeletal muscle mass, strength, and glucose homeostasis in people aged 40 years and older.

METHODS

This study was an American population-based cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES). Considering that some outcomes are only measured in specific survey cycles and subsamples, we established three data sets: a grip strength dataset (2011-2014, n=3772), a body mass components dataset (2011-2018, n=3279), and a glucose homeostasis dataset (1999-2018, n=9189). Dietary niacin and covariates were measured in all survey cycles. Linear regression or logistic regression models that adjusted for several main covariates, such as physical activity and diet, was used to evaluate the relationship between dietary niacin and grip strength, total lean mass, appendicular lean mass, total fat, trunk fat, total bone mineral content, homeostasis model assessment of insulin resistance (HOMA-IR), fasting blood glycose, fasting insulin and sarcopenia risk. Subgroup analyses, a trend test, an interaction test, and a restricted cubic spline were used for further exploration.

RESULTS

Higher dietary niacin intake was significantly correlated with higher grip strength (β 0.275, 95% confidence intervals [CI] 0.192-0.357), higher total lean mass (β 0.060, 95% CI 0.045-0.074), higher appendicular lean mass (β 0.025, 95% CI 0.018-0.033), and higher total bone mineral content (β 0.005, 95% CI 0.004-0.007). By contrast, higher dietary niacin intake was significantly associated with lower total fat (β -0.061, 95% CI -0.076 to -0.046), lower trunk fat (β -0.041, 95% CI -0.050 to -0.032) and lower sarcopenia risk (OR 0.460, 95% CI 0.233 to 0.907). In addition, dietary niacin significantly reduced HOMA-IR, fasting blood glucose (in participants without diabetes), and fasting insulin (p <0.05).

CONCLUSION

Niacin is associated with improved body composition (characterized by increased muscle mass and decreased fat content) and improved glucose homeostasis in dietary doses. Dietary niacin supplementation is a feasible way to alleviate age-related muscular loss.

Late-Night Overeating and All-Cause and Cardiovascular Disease Mortality in Adults Aged ≥ 50: A Cohort Study

BACKGROUND

Late-night overeating (LNOE) is closely associated with many health risk factors, but whether LNOE can increase the risk of death remains unknown. Thus, the prospective cohort study aimed to investigate the relationship between LNOE and mortality using data from the National Health and Nutrition Examination Survey.

METHODS

11,893 participants aged 50 years and older were included in the study. Dietary information was obtained through 24-h dietary recall interviews. Cox regression, subgroup, sensitivity, and restricted cubic spline analyses were used to assess the association between LNOE and mortality.

RESULTS

During a median follow-up of 8.3 years, 2,498 deaths occurred. After adjusting for major confounders, compared to the non-late-night eating (NLNE) group, the LNOE group was associated with higher risks of all-cause (HR = 1.47, 95% CI = 1.06-2.04) and cardiovascular disease (CVD) mortality (HR = 2.02, 95% CI = 1.13-3.60). No significant association was found between late-night eating (LNE) and mortality. Subgroup analyses showed that the LNOE group had a greater risk of all-cause and CVD mortality in participants older than 70 years, with alcohol consumption and hypertension and demonstrated an increased risk of all-cause mortality in males and higher CVD mortality in females.

CONCLUSION

The habit of LNOE was an independent risk factor for all-cause and CVD mortality in US adults aged 50 years and older, which was also influenced by age, sex, alcohol consumption, and hypertension.

Increased mitophagy protects cochlear hair cells from aminoglycoside-induced damage

Aminoglycosides exhibit ototoxicity by damaging mitochondria, which in turn generate reactive oxygen species that induce hair cell death and subsequent hearing loss. It is well known that damaged mitochondria are degraded by mitophagy, an important mitochondrial quality control system that maintains mitochondrial homeostasis and ensures cell survival. However, it is unclear whether dysregulation of mitophagy contributes to aminoglycoside-induced hair cell injury. In the current study, we found that PINK1-PRKN-mediated mitophagy was impaired in neomycin-treated hair cells. Our data suggested that mitochondrial recruitment of PRKN and phagophore recognition of damaged mitochondria during mitophagy were blocked following neomycin treatment. In addition, the degradation of damaged mitochondria by lysosomes was significantly decreased as indicated by the mitophagic flux reporter mt-mKeima. Moreover, we demonstrated that neomycin disrupted mitophagy through transcriptional inhibition of Pink1 expression, the key initiator of mitophagy. Moreover, we found that neomycin impaired mitophagy by inducing ATF3 expression. Importantly, treatment with a mitophagy activator could rescue neomycin-treated hair cells by increasing mitophagy, indicating that genetic modulation or drug intervention in mitophagy may have therapeutic potential for aminoglycoside-induced hearing loss.Abbreviations: AAV: adeno-associated virus; ABR: auditory brainstem response; ATF3: activating transcription factor 3; ATOH1/MATH1: atonal bHLH transcription factor 1; BafA1: bafilomycin A₁; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; COX4I1/COXIV: cytochrome c oxidase subunit 4I1; CTBP2/RIBEYE: C-terminal binding protein 2; DFP: deferiprone; EGFP: enhanced green fluorescent protein; FOXO3: forkhead box O3; GRIA2/GLUR2: glutamate receptor, ionotropic, AMPA2 (alpha 2); HC: hair cell; HSPD1/HSP60: heat shock protein 1 (chaperonin); IHC: inner hair cell; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MYO7A: myosin VIIA; OPTN: optineurin; OMM: outer mitochondrial membrane; PRKN: parkin RBR E3 ubiquitin protein ligase; PINK1: PTEN induced putative kinase 1; RT-qPCR: real-time quantitative polymerase chain reaction; TOMM20/TOM20: translocase of outer mitochondrial membrane 20; TUNEL: Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling; USP30: ubiquitin specific peptidase 30; XBP1: X-box binding protein 1.

Learning Curve for Flow Diversion of Posterior Circulation Aneurysms: A Long-Term International Multicenter Cohort Study

BACKGROUND AND PURPOSE

Flow diversion has gradually become a standard treatment for intracranial aneurysms of the anterior circulation. Recently, the off-label use of the flow diverters to treat posterior circulation aneurysms has also increased despite initial concerns of rupture and the suboptimal results. This study aimed to explore the change in complication rates and treatment outcomes across time for posterior circulation aneurysms treated using flow diversion and to further evaluate the mechanisms and variables that could potentially explain the change and outcomes.

MATERIALS AND METHODS

A retrospective review using a standardized data set at multiple international academic institutions was performed to identify patients with ruptured and unruptured posterior circulation aneurysms treated with flow diversion during a decade spanning January 2011 to January 2020. This period was then categorized into 4 intervals.

RESULTS

A total of 378 procedures were performed during the study period. Across time, there was an increasing tendency to treat more vertebral artery and fewer large vertebrobasilar aneurysms (P = .05). Moreover, interventionalists have been increasingly using fewer overlapping flow diverters per aneurysm (P = .07). There was a trend toward a decrease in the rate of thromboembolic complications from 15.8% in 2011-13 to 8.9% in 2018-19 (P = .34).

CONCLUSIONS

This multicenter experience revealed a trend toward treating fewer basilar aneurysms, smaller aneurysms, and increased usage of a single flow diverter, leading to a decrease in the rate of thromboembolic and hemorrhagic complications.

[Diagnostic value of platelet associated biomarkers in chronic periprosthetic joint infection]

Objective: To evaluate the diagnostic value of platelet count(PC),PC to mean platelet volume(MPV) ratio(PC/MPV) and plateletcrit(PCT) in chronic periprosthetic joint infection(PJI). Method: The medical records of 159 patients who underwent hip or knee revisions at Department of Joint Surgery,Affiliated Hospital of Qingdao University from August 2013 to June 2019 were retrospectively reviewed. There were 51 patients(26 knees and 25 hips) in the PJI group,which included 28 males and 23 females,aged (68.0±11.8)years (range:32 to 84 years)with a body mass index(BMI)of (26.1±3.6) kg/m².There were 116 patients(19 knees and 97 hips) in the aseptic loosening(AL) group,including 67 males and 49 females,aged (70.3±8.9)years(range:49 to 89 years)with a BMI of (25.0±3.6)kg/m².The plasma C-reactive protein(CRP),erythrocyte sedimentation rate(ESR),PC,MPV,PC/MPV and PCT levels of the two groups were recorded and analyzed. Receiver operating characteristic curve was used to calculate the sensitivity and specificity of each biomarker,expect for MPV,and the diagnostic value of each biomarker was compared according to the area under the curve(AUC).Independent-sample t test or Mann-Whitney U test were used for comparison between groups. Result: Compared with AL group,AJI group had significantly higher levels of CRP,ESR,PC,PC/MPV and PCT(all P<0.05),but lower level of MPV (P<0.05).The AUCs for CRP,ESR,PC,PC/MPV and PCT were 0.820, 0.829, 0.689, 0.668 and 0.676,respectively. Based on the Youden index,the optimal predictive cutoff for CRP was 11.12 mg/L,with a sensitivity of 74.4% and a specificity of 87.1%.The optimal predictive cutoff for ESR was 17.60 mm/1 h,with a sensitivity of 81.4% and a specificity of 75.3%.The optimal predictive cutoff for PC was 243.00×109/L,with a sensitivity of 60.6% and a specificity of 71.8%.The optimal predictive cutoff for PC/MPV was 24.95,the sensitivity was 58.1% and the specificity was 74.1%.And the optimal predictive cutoff for PCT was 0.24%,with a sensitivity of 69.8% and a specificity of 63.5%. Conclusion: PC,PC to MPV ratio and PCT were of limited value to diagnose PJI.

Risk factors of perioperative complications and transfusion following total hip arthroplasty in systemic lupus erythematosus patients

BACKGROUND

In recent years, hip arthroplasty rates in systemic lupus erythematosus (SLE) patients have been increasing rapidly. Although patients with SLE generally show beneficial or desirable functional outcomes following total hip arthroplasty (THA), it has been reported that SLE patients after THA have increased risk of postoperative complications, especially during the period of hospitalization.

OBJECTIVES

In the present study, we aimed to identify possible factors associated with complications or transfusion of THA in SLE patients during hospitalization.

METHODS

The present study was a retrospective study conducted in Peking Union Medical College Hospital. Data were collected from medical records of patients who underwent THA from January 2012 to June 2018. The primary outcome variable was perioperative complications, which was defined as having one or more of the following conditions: high fever, infection, impaired wound healing, venous thrombosis of the lower extremities, hematoma, arrhythmia, implant complications. The secondary outcome was perioperative transfusion.

RESULTS

During January 2012 to June 2018, 100 patients had taken the surgery of THA. After multivariate analysis, independent risk factors for perioperative complications were: age ≥ 45 years (p = 0.001), SLE with other connective tissue diseases (p = 0.029), high temperature (p = 0.030), positive anti-dsDNA antibody (p = 0.043), and Systemic Lupus International Collaborative Clinics/American College of Rheumatology (SLICC/ACR) Damage Index ≥ 3 (p = 0.008). Independent risk factors for perioperative transfusion were bilateral THA (p = 0.029), low hemoglobin (p = 0.021) and abnormal renal function (p = 0.021).

CONCLUSION

For SLE patients following THA, age > 45 years, SLE with other connective tissue disease, high temperature, positive anti-dsDNA antibody and SLICC/ACR Damage Index ≥ 3 were the risk factors of complications during hospitalization and bilateral THA, low hemoglobin and abnormal renal function were the risk factors of transfusion.

All-optical inhibitory dynamics in photonic neuron based on polarization mode competition in a VCSEL with an embedded saturable absorber

An all-optical spike inhibition scheme based on polarization-mode competition (PMC) in a vertical-cavity surface-emitting laser (VCSEL) with an embedded saturable absorber is proposed and investigated numerically. The inhibitory dynamics is characterized by spike amplitude and first-spike latency (FSL) for the first time, to the best of our knowledge. The effects of time differences between inhibitory and excitatory inputs, inputs strengths, bias current, as well as noise on the spike amplitude and FSL are examined. The results show that a spike can be triggered in the y-polarization mode by excitatory input and can be inhibited in the presence of inhibitory input due to PMC.

[Effect of attenuated expression of neuraminidase 3 via RNA interference on the proliferation and apoptosis of osteosarcoma MG-63 cells]

Objective

To investigate the effect of attenuated expression of neuraminidase 3 (NEU3) via RNA interference on the proliferation and apoptosis in human osteosarcoma MG-63 cells.

Methods

MG-63 cells were immunostained to observe the expression of NEU3. The cells were then divided into 5 groups: MG-63 cells in normal control group (group A) were not treated; MG-63 cells in 30, 50, and 100 nmol/L NEU3 RNA interference groups (groups B, C, and D) were transfected with 30, 50, and 100 nmol/L of NEU3 small interfering RNA (siRNA); negative control group (group E), MG-63 cells were transfected with different species negative siRNA (actin siRNA of mice, 50 nmol/L). The expression level of NEU3 mRNA was measured with real-time fluorescence quantitative PCR (qPCR). The proliferation of the cells was measured by cell counting kit 8 (CCK-8). The cell apoptosis rate was detected by flowcytometry (FCM). The expressions of cell apoptosis related proteins (Ras and Bcl-2) were detected by Western blot assay.

Results

NEU3 expressed in the cytoplasm of MG-63 cells under fluorescence microscope. The qPCR results showed that NEU3 mRNA levels were significantly lower in groups B, C, D than that in groups A and E ( P<0.05) after 24 hours of transfection; meanwhile, with the increase of siRNA concentration, NEU3 mRNA levels were significantly decreased ( P<0.05). The CCK-8 results showed that with the increase of siRNA concentration, the survival rate of MG-63 cells was significantly suppressed ( P<0.05) and the apoptosis rate of MG-63 cells was significantly accelerated ( P<0.05) after 48 hours of transfection. FCM results showed that after 24 hours of transfection, the number of live MG-63 cells decreased as that of the dead cells increased in groups B, C, D, and showing significant differences between 3 groups ( P<0.05). While the apoptosis rate in groups B, C, and D showed significant difference when compared with that of group A ( P<0.05); and when compared with group E, the apoptosis rate in groups C and D were significantly reduced ( P<0.05), but there was no significant difference between groups B and E ( P>0.05). The results of Western bolt assay showed that the protein levels of Ras and Bcl-2 in groups B and C were not significantly different from groups A and E ( P>0.05), while the protein levels of Ras and Bcl-2 were significantly decreased in group D ( P<0.05).

Conclusion

Attenuated expression of NEU3 could inhibit the survival of MG-63 cells and accelerate its apoptosis. The results suggest that NEU3 could be a possible target for treating osteosarcoma.

A Novel Rodent Orthotopic Forelimb Transplantation Model That Allows for Reliable Assessment of Functional Recovery Resulting From Nerve Regeneration

Improved nerve regeneration and functional outcomes would greatly enhance the utility of vascularized composite allotransplantation (VCA) such as hand and upper extremity transplantation. However, research aimed at achieving this goal has been limited by the lack of a functional VCA animal model. We have developed a novel rat midhumeral forelimb transplant model that allows for the characterization of upper extremity functional recovery following transplantation. At the final end point of 12 weeks, we found that animals with forelimb transplantation including median, ulnar and radial nerve coaptation demonstrated significantly improved grip strength and forelimb function as compared to forelimb transplantation without nerve approximation (grip strength: 1.71N ± 0.57 vs. no appreciable recovery; IBB scale: 2.6 ± 0.7? vs. 0.8 ± 0.40; p = 0.0005), and similar recovery to nerve transection-and-repair only (grip strength: 1.71N ± 0.57 vs. 2.03 ± 0.42.6; IBB scale: 2.6 ± 0.7 vs. 2.8 ± 0.8; p = ns). Moreover, all forelimb transplant animals with nerve coaptation displayed robust axonal regeneration with myelination and reduced flexor muscle atrophy when compared to forelimb transplant animals without nerve coaptation. In conclusion, this is the first VCA small-animal model that allows for reliable and reproducible measurement of behavioral functional recovery in addition to histologic evaluation of nerve regeneration and graft reinnervation.

Reconstructing the normal velocities of acoustic sources in noisy environments using a rigid microphone array

An acoustic source identification technique with single layer pressure measurement is presented to reconstruct normal velocities of target sources in noisy environments. The theory for this reconstruction is developed from the inverse patch transfer functions method which is supposed to combine measurements of pressure and velocity on a surface surrounding the source. The rigid microphone array is called an acoustic mask, which is designed to obtain pressure on the Neumann boundary condition and realized by microphones flush mounted on the aluminum plate. The validity of the proposed method is demonstrated by giving the normal velocities of two baffled loudspeakers in a noisy environment in the simulation and experiment. Another experiment of a clamped steel plate is further presented to illustrate the ability of the acoustic mask to obtain the partial velocity field of interest without reconstruction of the whole source surface velocity. The accuracy of this technique is demonstrated by comparison with the accelerometer method.

Similar enhancement of BK(Ca) channel function despite different aerobic exercise frequency in aging cerebrovascular myocytes

Aerobic exercise showed beneficial influence on cardiovascular systems in aging, and mechanisms underlying vascular adaption remain unclear. Large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels play critical roles in regulating cellular excitability and vascular tone. This study determined the effects of aerobic exercise on aging-associated functional changes in BK(Ca) channels in cerebrovascular myocytes, Male Wistar rats aged 20-22 months were randomly assigned to sedentary (O-SED), low training frequency (O-EXL), and high training frequency group (O-EXH). Young rats were used as control. Compared to young rats, whole-cell BK(Ca) current was decreased, and amplitude of spontaneous transient outward currents were reduced. The open probability and Ca(2+)/voltage sensitivity of single BK(Ca) channel were declined in O-SED, accompanied with a reduction of tamoxifen-induced BK(Ca) activation; the mean open time of BK(Ca) channels was shortened whereas close time was prolonged. Aerobic exercise training markedly alleviated the aging-associated decline independent of training frequency. Exercise three times rather than five times weekly may be a time and cost-saving training volume required to offer beneficial effects to offset the functional declines of BK(Ca) during aging.

Metal-insulator transition in the quasi-one-dimensional transport of fractional quantum Hall states

We investigate edge state transmission in quantum point contacts (QPCs) in the fractional quantum-Hall regime, finding behavior reminiscent of a metal-insulator transition. The transition is suggested by an unusual behavior of the differential conductance in the fractional-quantum-Hall regime, and by the presence of a fixed point and universal scaling in the temperature dependence of the linear conductance. Noting that the 0.7 feature evolves continuously into a last fractional plateau at high magnetic fields, we suggest that this still unresolved feature may itself be viewed as a manifestation of a local, microscopic, metal-insulator transition.

Sensory processing differences and urinary incontinence in school-aged children

OBJECTIVE

Urinary Incontinence (UI) is a common problem among school-aged children (5-11 years). Symptoms such as urgency, diminished awareness of wetting, or apparent apathy may represent differences in sensory processing (SP). This study aims to describe the SP abilities of incontinent school-aged children with typical development to determine if they differ from established norms for continent children.

MATERIALS AND METHODS

The SP abilities of 209 school-aged children with UI were evaluated using the short sensory profile (SSP), a judgment-based caregiver questionnaire, then compared with established norms using descriptive and inferential statistics.

RESULTS

Forty-four percent of children showed significant differences in global SP with the greatest differences noted in tactile sensitivity. Higher section subscores were also noted in "seeks sensation/under responsive" and "auditory sensitivity". Children with dysfunctional voiding (DV) were more likely to show global differences (p = 0.015), differences in "seeks sensation" (p = 0.006), and auditory sensitivity (p = 0.041). The odds for low tactile sensitivity scores were five times greater for children with UI and DV (p = 0.006).

CONCLUSION

These results suggest that differences in SP may be found among typical school aged children with UI. Continued research is indicated to understand the significance of the study results.

Modeling transient sound propagation over an absorbing plane by a half-space interpolated time-domain equivalent source method

A half-space interpolated time-domain equivalent source method (ITDESM) is proposed to model the transient sound propagation over an absorbing plane. In this approach, a closed-form transient half-space Green's function (i.e., the impulse response function in three-dimensional space) for a pure absorbing infinite plane is introduced to develop the half-space ITDESM formulation. Instead of the free transient Green's function employed in the conventional ITDESM, such Green's function contains the reflection effect of the absorbing plane. As a numerical example, reconstructing the transient pressure fields from two monopole sources is depicted, where both monopoles are located in front of an infinite plane with absorbing impedance. Simulation results indicate that the half-space ITDESM can reconstruct the half-space transient sound fields in both the space and time domains very well. The proposed method is also investigated by taking into account the measurement noise in the reconstruction process. An experiment of an impacted steel plate above a glass wool board is presented to illustrate the validity of the proposed method under actual conditions.

On the zero-bias anomaly and Kondo physics in quantum point contacts near pinch-off

We investigate the linear and non-linear conductance of quantum point contacts (QPCs), in the region near pinch-off where Kondo physics has previously been connected to the appearance of the 0.7 feature. In studies of seven different QPCs, fabricated in the same high-mobility GaAs/AlGaAs heterojunction, the linear conductance is widely found to show the presence of the 0.7 feature. The differential conductance, on the other hand, does not generally exhibit the zero-bias anomaly (ZBA) that has been proposed to indicate the Kondo effect. Indeed, even in the small subset of QPCs found to exhibit such an anomaly, the linear conductance does not always follow the universal temperature-dependent scaling behavior expected for the Kondo effect. Taken collectively, our observations demonstrate that, unlike the 0.7 feature, the ZBA is not a generic feature of low-temperature QPC conduction. We furthermore conclude that the mere observation of the ZBA alone is insufficient evidence for concluding that Kondo physics is active. While we do not rule out the possibility that the Kondo effect may occur in QPCs, our results appear to indicate that its observation requires a very strict set of conditions to be satisfied. This should be contrasted with the case of the 0.7 feature, which has been apparent since the earliest experimental investigations of QPC transport.

Hierarchical Bayesian modeling of heterogeneous variances in average daily weight gain of commercial feedlot cattle

Variability in ADG of feedlot cattle can affect profits, thus making overall returns more unstable. Hence, knowledge of the factors that contribute to heterogeneity of variances in animal performance can help feedlot managers evaluate risks and minimize profit volatility when making managerial and economic decisions in commercial feedlots. The objectives of the present study were to evaluate heteroskedasticity, defined as heterogeneity of variances, in ADG of cohorts of commercial feedlot cattle, and to identify cattle demographic factors at feedlot arrival as potential sources of variance heterogeneity, accounting for cohort- and feedlot-level information in the data structure. An operational dataset compiled from 24,050 cohorts from 25 U. S. commercial feedlots in 2005 and 2006 was used for this study. Inference was based on a hierarchical Bayesian model implemented with Markov chain Monte Carlo, whereby cohorts were modeled at the residual level and feedlot-year clusters were modeled as random effects. Forward model selection based on deviance information criteria was used to screen potentially important explanatory variables for heteroskedasticity at cohort- and feedlot-year levels. The Bayesian modeling framework was preferred as it naturally accommodates the inherently hierarchical structure of feedlot data whereby cohorts are nested within feedlot-year clusters. Evidence for heterogeneity of variance components of ADG was substantial and primarily concentrated at the cohort level. Feedlot-year specific effects were, by far, the greatest contributors to ADG heteroskedasticity among cohorts, with an estimated ∼12-fold change in dispersion between most and least extreme feedlot-year clusters. In addition, identifiable demographic factors associated with greater heterogeneity of cohort-level variance included smaller cohort sizes, fewer days on feed, and greater arrival BW, as well as feedlot arrival during summer months. These results support that heterogeneity of variances in ADG is prevalent in feedlot performance and indicate potential sources of heteroskedasticity. Further investigation of factors associated with heteroskedasticity in feedlot performance is warranted to increase consistency and uniformity in commercial beef cattle production and subsequent profitability.

Oscillation of clock and clock controlled genes induced by serum shock in human breast epithelial and breast cancer cells: regulation by melatonin

This study investigates differences in expression of clock and clock-controlled genes (CCGs) between human breast epithelial and breast cancer cells and breast tumor xenografts in circadian intact rats and examines if the pineal hormone melatonin influences clock gene and CCG expression. Oscillation of clock gene expression was not observed under standard growth conditions in vitro, however, serum shock (50% horse serum for 2 h) induced oscillation of clock gene and CCG expression in MCF-10A cells, which was repressed or disrupted in MCF-7 cells. Melatonin administration following serum shock differentially suppressed or induced clock gene (Bmal1 and Per2) and CCG expression in MCF10A and MCF-7 cells. These studies demonstrate the lack of rhythmic expression of clock genes and CCGs of cells in vitro and that transplantation of breast cancer cells as xenografts into circadian competent hosts re-establishes a circadian rhythm in the peripheral clock genes of tumor cells.

Combined hepatocellular cholangiocarcinoma originating from hepatic progenitor cells: immunohistochemical and double-fluorescence immunostaining evidence

AIMS

Combined hepatocellular cholangiocarcinoma (CHC) is a rare form of primary liver cancer, showing a mixture of hepatocellular and biliary features. Data suggest that most CHC arise from hepatic progenitor cells (HPCs). The aim was to investigate the origin of CHC.

METHODS AND RESULTS

Twelve cases of CHC were studied by immunohistochemistry for hepatocytic (hepPar1, alpha-fetoprotein), cholangiocytic cytokeratin [(CK) 7, CK19], hepatic progenitor cell (OV-6), haematopoietic stem cell (c-kit, CD34), as well as CD45 and chromogranin-A markers. The combination of double-fluorescence immunostaining consisted of HepPar1 with CK19, and c-kit with OV-6. All 12 cases demonstrated more or less transitional areas, with strands/trabeculae of small, uniform, oval-shaped cells including scant cytoplasm and hyperchromatic nuclei embedded within a thick, desmoplastic stroma; however, two cases were found to consist entirely of such transitional areas. Simultaneous co-expression of hepPar1 and CK7, or CK19, was demonstrated in 10/12 (83.3%) cases of CHC. c-kit expression was noted in 10/12 (83.3%) cases, of which 7/10 (70%) showed co-expression of OV-6.

CONCLUSIONS

The results suggest that CHC are of HPC origin, supporting the concept that human hepatocarcinogenesis may originate from the transformation of HPCs.

Entropy maximization constrained by solvent flatness: a new method for macromolecular phase extension and map improvement

A practical generally applicable procedure for exponential modeling to maximum likelihood of macromolecular data sets constrained by a moderately large basis set of reliable phases and a molecular envelope is described, based on the computer program MICE [Bricogne & Gilmore (1990). Acta Cryst. A46, 284-297]. Procedures were first tested with simulated data sets. Exact and randomly perturbed amplitudes and phases were generated, together with a known envelope for solvent-free protein and for protein in an electron-dense crystal mother liquor typical of many real protein crystals. These experiments established useful guidelines and values for various parameters. Tests with basis sets chosen from the largest amplitudes indicate that exponential models with considerable correct extrapolated phase and amplitude information can be constructed from as few as 16% of the total number of reflections, with mean phase errors of about 30 degrees, at resolution limits of either 5 or 3 A. When the shape of the solvent channels in macromolecular crystals is known, it offers an important additional source of information. MICE was, therefore, adapted to average the density outside the molecular boundary defined by an input envelope. This flattening process imposes a uniform density distribution in solvent-filled channels as an additional constraint on the exponential model and is analogous to the treatment of solvent in conventional solvent flattening. Experimental data for cytidine deaminase, a structure recently solved by making extensive use of conventional solvent flattening, provides an example of the performance of maximum-entropy methods in a real situation and a compelling comparison of this method to standard procedures. Exponential models of the electron density constrained by the most reliable phases obtained by multiple isomorphous replacement with anomalous scattering (MIRAS) (figure of merit > 0.7, representing 34% of the total number of reflections) and by the envelope give rise to centroid electron-density maps which are quantitatively superior by numerous statistical criteria to conventionally solvent-flattened density. Similarity of these maps to the 2F(obs) - F(calc) map calculated with phases obtained after crystallographic refinement of the model implies that maximum-entropy extrapolation provides better phases for the remaining 66% of the reflections than the original centroid MIRAS distributions. Importantly, the solvent-flattened electron density, although it did permit interpretation of the map which was not readily accomplished with the MIRAS map, contains substantial errors. It is proposed that errors of this sort may account for previously noted deficiencies of the solvent-flattening method [Fenderson, Herriott & Adman (1990). J. Appl. Cryst. 23, 115-131] and for the occasional tendency of incorrect interpretations to be 'locked in' by crystallographic refinement [Brändén & Jones (1990). Nature (London), 343, 687-689, and references cited therein]. Solvent flattening with combined maximization of entropy and likelihood represents a phase-refinement path independent of atomic models, using the experimental amplitudes and the most reliable phases. It should, therefore, become a valuable and generally useful procedure in macromolecular crystal structure determination.

MR Quantification of Flow in Children with Vein of Galen Malformations

SUMMARY

Vein of Galen vascular malformations are either Vein of Galen Aneurysmal malformations (VGAMs) or Vein of Galen Aneurysmal Dilatations (VGADs). VGAMs may be of the choroidal or mural type and are fistulas associated with the precursor of the vein of Galen. The treatment of VGAMs is aimed at controlling the size of the vascular shunt since it is believed that the shunt is responsible for venous hypertension, cardiac stress, delayed development and may be so large as to damage the brain. In VGAMs as noted by Berenstein and Lasjaunias. Absolute measures of flow may contribute to our understanding of CNS disease and permit objective measures of the success or failure of therapeutic interventions (5). MR phase contrast cine angiographic techniques can be employed to measure bulk flow in intracranial vessels. Vein of Galen vascular malformations are an ideal model to measure venous flow as the draining vein is large and angiographic evaluation is limited. Thus our goal was to develop an objective non-invasive method of measuring vascular flow in VGAMs and VGADs (6) . Herein we report our experience using this technique in a group of patients with Vein of Galen vascular malformations. We also hypothesized that the degree of shunting would correlate to the degree of cardiac stress and be an indicator of optimal timing for intervention. We believe that we have succeeded in our goal to develop an objective, non-invasive method of shunt quantification using velocity encoded MR sequences. This promises new insight into the hemodynamics, natural history and treatment response of vascular malformations.

On the relationship between protein stability and folding kinetics: a comparative study of the N-terminal domains of RNase HI, E. coli and Bacillus stearothermophilus L9

There is currently a great deal of interest in proteins that fold in a single highly cooperative step. Particular attention has been focused on elucidating the factors that govern folding rates of simple proteins. Recently, the topology of the native state has been proposed to be the most important determinant of their folding rates. Here we report a comparative study of the folding of three topologically equivalent proteins that adapt a particularly simple alpha/beta fold. The folding kinetics of the N-terminal domain of RNase HI and the N-terminal domain of the ribosomal protein L9 from Escherichia coli (eNTL9) were compared to the previously characterized N-terminal domain of L9 from Bacillus stearothermophilus (bNTL9). This 6.2 kDa protein, which is one of simplest examples of the ABCalphaD motif, folds via a two-state mechanism on the millisecond to submillisecond time scale. The RNase HI domain and bNTL9 have very similar tertiary structures but there is little similarity in primary sequence. bNTL9 and eNTL9 share the same biological function and a similar primary sequence but differ significantly in stability. Fluorescence-detected stopped-flow experiments showed that the three proteins fold in a two-state fashion. The folding rates in the absence of denaturant were found to be very different, ranging form 21 s(-1) to 790 s(-1) at 10 degrees C. The diverse folding rates appear to reflect large differences in the stability of the proteins. When compared at an isostability point, the folding rates converged to a similar value and there is a strong linear correlation between the log of the folding rate and stability for this set of proteins. These observations are consistent with the idea that stability can play an important role in dictating relative folding rates among topologically equivalent proteins.

Binding of low density lipoproteins to lipoprotein lipase is dependent on lipids but not on apolipoprotein B

Lipoprotein lipase (LPL) efficiently mediates the binding of lipoprotein particles to lipoprotein receptors and to proteoglycans at cell surfaces and in the extracellular matrix. It has been proposed that LPL increases the retention of atherogenic lipoproteins in the vessel wall and mediates the uptake of lipoproteins in cells, thereby promoting lipid accumulation and plaque formation. We investigated the interaction between LPL and low density lipoproteins (LDLs) with special reference to the protein-protein interaction between LPL and apolipoprotein B (apoB). Chemical modification of lysines and arginines in apoB or mutation of its main proteoglycan binding site did not abolish the interaction of LDL with LPL as shown by surface plasmon resonance (SPR) and by experiments with THP-I macrophages. Recombinant LDL with either apoB100 or apoB48 bound with similar affinity. In contrast, partial delipidation of LDL markedly decreased binding to LPL. In cell culture experiments, phosphatidylcholine-containing liposomes competed efficiently with LDL for binding to LPL. Each LDL particle bound several (up to 15) LPL dimers as determined by SPR and by experiments with THP-I macrophages. A recombinant NH(2)-terminal fragment of apoB (apoB17) bound with low affinity to LPL as shown by SPR, but this interaction was completely abolished by partial delipidation of apoB17. We conclude that the LPL-apoB interaction is not significant in bridging LDL to cell surfaces and matrix components; the main interaction is between LPL and the LDL lipids.

The distinct roles of T cell-derived cytokines and a novel follicular dendritic cell-signaling molecule 8D6 in germinal center-B cell differentiation

Germinal center-B (GC-B) cells differentiate into memory B cells and plasma cells (PC) through interaction with T cells and follicular dendritic cells (FDC). Activated T cell and FDC play distinct roles in this process. The detailed kinetic experiments revealed that cytokines secreted by activated T cells determined the pathway of GC-B cell differentiation. IL-4 directs GC-B cells to differentiate into memory B cells, whereas IL-10 steers them into PC. FDC/HK cells do not direct either pathway, but provide signals for proliferation of GC-B cells. A novel FDC-signaling molecule 8D6 (FDC-SM-8D6) produced by FDC augments PC generation in the GC. FDC-SM-8D6-specific mAb blocked PC generation and IgG secretion but not memory B cell proliferation. COS cells expressing FDC-SM-8D6 enhanced GC-B cell proliferation and Ab secretion, which was blocked by mAb 8D6. In the cultures with B cell subsets, PC generation was inhibited by mAb 8D6 in the cultures with CD27(+) B cells but not in the culture with CD27(-) B cells, suggesting that CD27(+) PC precursor is the specific target of FDC-SM-8D6 stimulation.

The crystal structure of Escherichia coli MoeA and its relationship to the multifunctional protein gephyrin

BACKGROUND

Molybdenum cofactor (Moco) biosynthesis is an evolutionarily conserved pathway present in archaea, eubacteria, and eukaryotes. In humans, genetic abnormalities in the biosynthetic pathway result in Moco deficiency, which is accompanied by severe neurological symptoms and death shortly after birth. The Escherichia coli MoeA and MogA proteins are involved in the final step of Moco biosynthesis: the incorporation of molybdenum into molybdopterin (MPT), the organic pyranopterin moiety of Moco.

RESULTS

The crystal structure of E. coli MoeA has been refined at 2 A resolution and reveals that the highly elongated MoeA monomer consists of four clearly separated domains, one of which is structurally related to MogA, indicating a divergent evolutionary relationship between both proteins. The active form of MoeA is a dimer, and a putative active site appears to be localized to a cleft formed between domain II of the first monomer and domains III and IV of the second monomer.

CONCLUSIONS

In eukaryotes, MogA and MoeA are fused into a single polypeptide chain. The corresponding mammalian protein gephyrin has also been implicated in the anchoring of glycinergic receptors to the cytoskeleton at inhibitory synapses. Based on the structures of MoeA and MogA, gephyrin is surmised to be a highly organized molecule containing at least five domains. This multidomain arrangement could provide a structural basis for its functional diversity. The oligomeric states of MoeA and MogA suggest how gephyrin could assemble into a hexagonal scaffold at inhibitory synapses.

Non-Hodgkin Lymphomas of Mice

Studies of lymphoid neoplasms occurring in normal or genetically engineered mice have revealed parallels and differences to non-Hodgkin lymphomas (NHL) of humans. Some mouse lymphomas have strong histologic similarities to the human NHL subsets including precursor B- and T-cell lymphoblastic, small lymphocytic, splenic marginal zone, and diffuse large-cell B-cell lymphomas (DLCL); whether molecular parallels also exist is under study. Others mouse types such as sIg+ lymphoblastic B-cell lymphoma have no histologic equivalent in human NHL even though they share molecular deregulation of BCL6 with human DLCL. Finally, Burkitt lymphoma does not appear to occur naturally in mice, but it can be induced with appropriately engineered transgenes.

Doppler standard deviation imaging for clinical monitoring of in vivo human skin blood flow

We used a novel phase-resolved optical Doppler tomographic (ODT) technique with very high flow-velocity sensitivity (10microm/s) and high spatial resolution (10microm) to image blood flow in port-wine stain (PWS) birthmarks in human skin. In addition to the regular ODT velocity and structural images, we use the variance of blood flow velocity to map the PWS vessels. Our device combines ODT and therapeutic systems such that PWS blood flow can be monitored in situ before and after laser treatment. To the authors' knowledge this is the first clinical application of ODT to provide a fast semiquantitative evaluation of the efficacy of PWS laser therapy in situ and in real time.

Effects of hepatic artery chemotherapeutic embolization combined with perfusing LAK cells into hepatic artery after radical operation of liver cancer

OBJECTIVE

To evaluate the effects of hepatic artery chemotherapeutic embolization combined with perfusing LAK cells/interleukin 2 into hepatic artery after radical operation of liver cancer.

METHODS

Random divide 42 cases into two groups who had accepted radical operation of liver cancer: 21 cases who accepted hepatic artery chemotherapeutic embolization combined with perfusing LAK cells/interleukin 2 into hepatic artery as observing group, 21 cases accepted simply hepatic artery chemotherapeutic embolization as control group.

RESULTS

The intrahepatic recurrence rates of 1, 2, and 3 years were 0, 19.05%, 57.14% in observing group, lower than 28.57%, 47.62%, 85.71% of control group (chi(2)=4.86, 3. 86 and 4.20 respectively, P<0.05). The survival rates of 2 and 3 years were 85.71%, 61.90% in observing group, higher than 57.14%, 28. 57% of control group (chi(2)=4.20 and 4.71, P<0.05).

CONCLUSION

Hepatic artery chemotherapeutic embolization combined with perfusing LAK cells/interleukin 2 into hepatic artery is an effective therapeutic method to control intrahepatic recurrence rates and raise the survival rates of the patients.

Phase-resolved optical coherence tomography and optical Doppler tomography for imaging blood flow in human skin with fast scanning speed and high velocity sensitivity

We have developed a novel phase-resolved optical coherence tomography (OCT) and optical Doppler tomography (ODT) system that uses phase information derived from a Hilbert transformation to image blood flow in human skin with fast scanning speed and high velocity sensitivity. Using the phase change between sequential scans to construct flow-velocity imaging, this technique decouples spatial resolution and velocity sensitivity in flow images and increases imaging speed by more than 2 orders of magnitude without compromising spatial resolution or velocity sensitivity. The minimum flow velocity that can be detected with an axial-line scanning speed of 400 Hz and an average phase change over eight sequential scans is as low as 10 microm/s, while a spatial resolution of 10 microm is maintained. Using this technique, we present what are to our knowledge the first phase-resolved OCT/ODT images of blood flow in human skin.

[The development of Model Cihang-2000 mini multi-function electrocardiograph]

The Model Cihang-2000 mini multi-function electrocardiograph is introduced in this paper. A lot of advanced electronic techniques and data processing techniques are used in this instrument. It is not only high in quality and small in size, but also strong in function.

Identification of a novel transcriptional silencer in the protein-coding region of the human CYP2C9 gene

A novel regulatory element (27 bp) which confers transcriptional repression was identified within the protein-coding region immediately after the translation start codon in the human cytochrome P450 (CYP) 2C9 gene. Deletion of this element increased transcriptional activity in HepG2 cells by transient transfection assay. Nuclear protein extracts from HepG2 cells and human liver were found in electrophoretic mobility shift assays to bind specifically to the 27 bp element. A putative binding protein was partially purified by DNA-affinity chromatography and was determined by Southwestern blotting to have a molecular weight of approx. 100 kDa. Studies with mutated competitor oligonucleotides established that binding of the nuclear protein to the 27 bp cis-element was dependent upon two 6 bp direct repeats (5'-CTTGTG-3') that were separated by three bases. It is possible that this novel cis-acting element may be involved in the negative regulation of CYP2C9.

Th1/Th2 cytokine profiles in the nasopharyngeal lymphoid tissues of children with recurrent otitis media

The cytokine profile in adenoidal lymphoid tissue was studied in 22 patients. Lymphocytes from adenoid tissues and peripheral blood were submitted for cytokine assays using an enzyme-linked immunosorbent assay kit for interferon-gamma, interleukin (IL)-2, IL-4, IL-5, IL-6, and IL-10. Adenoidal lymphocytes appear to produce significantly less Th1 cytokines (IL-2, interferon gamma) compared to the patient's peripheral blood lymphocytes, whereas IL-4 and IL-5 (Th2 cytokines) appear to be synthesized to the same extent as, if not slightly more than, in the homologous peripheral blood lymphocytes. Because the relationship between Th1 and Th2 cytokines is extremely important in modulating the immune response, it is advisable to determine the role of the cytokine profiles of T-lymphocytes in the nasopharynx and its relationship to the development of inflammation of the eustachian tube and middle ear.