Non-Invasive Clinical Parameters for the Prediction of Urodynamic Bladder Outlet Obstruction: Analysis Using Causal Bayesian Networks

Purpose

To identify non-invasive clinical parameters to predict urodynamic bladder outlet obstruction (BOO) in patients with benign prostatic hyperplasia (BPH) using causal Bayesian networks (CBN).

Subjects and Methods

From October 2004 to August 2013, 1,381 eligible BPH patients with complete data were selected for analysis. The following clinical variables were considered: age, total prostate volume (TPV), transition zone volume (TZV), prostate specific antigen (PSA), maximum flow rate (Qmax), and post-void residual volume (PVR) on uroflowmetry, and International Prostate Symptom Score (IPSS). Among these variables, the independent predictors of BOO were selected using the CBN model. The predictive performance of the CBN model using the selected variables was verified through a logistic regression (LR) model with the same dataset.

Results

Mean age, TPV, and IPSS were 6.2 (±7.3, SD) years, 48.5 (±25.9) ml, and 17.9 (±7.9), respectively. The mean BOO index was 35.1 (±25.2) and 477 patients (34.5%) had urodynamic BOO (BOO index ≥40). By using the CBN model, we identified TPV, Qmax, and PVR as independent predictors of BOO. With these three variables, the BOO prediction accuracy was 73.5%. The LR model showed a similar accuracy (77.0%). However, the area under the receiver operating characteristic curve of the CBN model was statistically smaller than that of the LR model (0.772 vs. 0.798, p = 0.020).

Conclusions

Our study demonstrated that TPV, Qmax, and PVR are independent predictors of urodynamic BOO.     

TURP联合经尿道膀胱颈切开术治疗小体积前列腺增生所致膀胱出口梗阻的疗效分析

目的:探讨经尿道前列腺电切术(TURP)联合经尿道膀胱颈切开术(TUIBN)治疗小体积前列腺增生(BPH)所致膀胱出口梗阻的疗效。方法:选择2009年1月~2013年12月我院收治的小体积BPH患者,其中单纯经尿道前列腺电切术(TURP组)48例,经尿道前列腺电切术联合经尿道膀胱颈切开术(TURP+TUIBN组)48例。比较两组的术前、术后国际前列腺症状评分(IPSS)、残余尿量(PVR)、最大尿流率(Qmax)等,以及术后并发症的发生情况。结果:TURP+TUIBN组术中出血量较TURP组明显增多(P0.05),两组手术时间、组织切除质量比较,差异均无统计学意义(P0.05);与TURP组比较,TURP+TUIBN组术后6个月IPSS评分、PVR明显下降,Qmax、膀胱压力明显上升(P0.05);TURP+TUIBN组并发症发生率为4.2%,显著低于TURP组16.7%(P0.05)。结论:TURP+TUIBN治疗小体积前BPH所致膀胱出口梗阻,可彻底切除增生腺体,消除小体积BPH的各种梗阻因素,减少术后膀胱颈挛缩的发生。     

Sleep Cystometrography: A Preliminary Study of Bladder Function During Sleep

Bladder function during sleep was studied by the use of a cystometer which recorded detrusor contractions and intravesical pressure as urine accumulated in the bladder during diuresis. The cystometrographic tracing was obtained while the patient was awake. A detrusor contraction can occur during sleep. Results of such studies on five patients are presented, with photographs of representative cystometrographic tracings.The general pattern of the cystometrogram during sleep was found to be different from that obtained while the patient was awake. A detrusor contraction can occur during sleep and may subsequently: (a) subside without awakening the patient; (b) be associated with the involuntary escape of urine or flatus; or (c) cause the patient to awaken. It is suggested that detrusor contractions rather than increases in urinary volume are responsible for the individual''s awakening at night to urinate.In the light of these observations, further study of patients with enuresis and those with non-obstructive nocturia is required.     

A Simple Stain for Myelin in Frozen Sections: A Modification of Mahon's Method

A simple and rapid method for demonstrating myelinated nerve fibers in frozen sections of the central and peripheral nervous system is described. Material fixed by perfusion with mixed aldehydes gives the best results but the method also works on specimens fixed by immersion in formaldehyde. Frozen sections varying in thickness from 15-50 μm are mounted on slides subbed with chrome alum-gelatin. After hydration (60-140 min), Sections are mordanted (20-40 min) in 2.5% iron alum and rinsed briefly in three changes of distilled H₂O (total 2 min). Staining is for 60-180 min in 40 cc freshly made 10% alcoholic hematoxylin diluted with 165 cc distilled H₂O to which 15 cc saturated Li₂CO₂is added. the sections are washed in distilled H₂O (5-15 min) and dehydrated in graded alcohols without differentiation in mordant, and covered. Myelin stains a dark blue-purple against a light grey background. Fiber tracts, as well as individual myelinated fibers, are clearly demonstrated.     

Simple Scoring System and Artificial Neural Network for Knee Osteoarthritis Risk Prediction: A Cross-Sectional Study

Background

Knee osteoarthritis (OA) is the most common joint disease of adults worldwide. Since the treatments for advanced radiographic knee OA are limited, clinicians face a significant challenge of identifying patients who are at high risk of OA in a timely and appropriate way. Therefore, we developed a simple self-assessment scoring system and an improved artificial neural network (ANN) model for knee OA.

Methods

The Fifth Korea National Health and Nutrition Examination Surveys (KNHANES V-1) data were used to develop a scoring system and ANN for radiographic knee OA. A logistic regression analysis was used to determine the predictors of the scoring system. The ANN was constructed using 1777 participants and validated internally on 888 participants in the KNHANES V-1. The predictors of the scoring system were selected as the inputs of the ANN. External validation was performed using 4731 participants in the Osteoarthritis Initiative (OAI). Area under the curve (AUC) of the receiver operating characteristic was calculated to compare the prediction models.

Results

The scoring system and ANN were built using the independent predictors including sex, age, body mass index, educational status, hypertension, moderate physical activity, and knee pain. In the internal validation, both scoring system and ANN predicted radiographic knee OA (AUC 0.73 versus 0.81, p<0.001) and symptomatic knee OA (AUC 0.88 versus 0.94, p<0.001) with good discriminative ability. In the external validation, both scoring system and ANN showed lower discriminative ability in predicting radiographic knee OA (AUC 0.62 versus 0.67, p<0.001) and symptomatic knee OA (AUC 0.70 versus 0.76, p<0.001).

Conclusions

The self-assessment scoring system may be useful for identifying the adults at high risk for knee OA. The performance of the scoring system is improved significantly by the ANN. We provided an ANN calculator to simply predict the knee OA risk.     

Mechanical Intestinal Obstruction in a Porcine Model: Effects of Intra-Abdominal Hypertension. A Preliminary Study

Introduction

Mechanical intestinal obstruction is a disorder associated with intra-abdominal hypertension and abdominal compartment syndrome. As the large intestine intraluminal and intra-abdominal pressures are increased, so the patient’s risk for intestinal ischaemia. Previous studies have focused on hypoperfusion and bacterial translocation without considering the concomitant effect of intra-abdominal hypertension. The objective of this study was to design and evaluate a mechanical intestinal obstruction model in pigs similar to the human pathophysiology.

Materials and Methods

Fifteen pigs were divided into three groups: a control group (n = 5) and two groups of 5 pigs with intra-abdominal hypertension induced by mechanical intestinal obstruction. The intra-abdominal pressures of 20 mmHg were maintained for 2 and 5 hours respectively. Hemodynamic, respiratory and gastric intramucosal pH values, as well as blood tests were recorded every 30 min.

Results

Significant differences between the control and mechanical intestinal obstruction groups were noted. The mean arterial pressure, cardiac index, dynamic pulmonary compliance and abdominal perfusion pressure decreased. The systemic vascular resistance index, central venous pressure, pulse pressure variation, airway resistance and lactate increased within 2 hours from starting intra-abdominal hypertension (p<0.05). In addition, we observed increased values for the peak and plateau airway pressures, and low values of gastric intramucosal pH in the mechanical intestinal obstruction groups that were significant after 3 hours.

Conclusion

The mechanical intestinal obstruction model appears to adequately simulate the pathophysiology of intestinal obstruction that occurs in humans. Monitoring abdominal perfusion pressure, dynamic pulmonary compliance, gastric intramucosal pH and lactate values may provide insight in predicting the effects on endorgan function in patients with mechanical intestinal obstruction.     

重组人超氧化物歧化酶化学修饰的初步研究

在高效表达重组人铜锌超氧化物歧化酶(rh Cu/Zn SOD),并纯化得到比活大于4000单位的 rh Cu/Zn SOD 纯品的基础上,采用活化酯法将聚乙二醇(PEG)与 rhCu/Zn SOD 交联,获得分子量约6万的 PEG-SOD 交联物.经 PEG 修饰的酶稳定性增强,表现为对酸、碱和热的耐受力均较未交联酶高.修饰酶的生物半衰期为15h,是天然酶的90倍,酶活性保留80%以上.还实验观察了修饰剂用量与修饰酶保留活性之间的关系.     

A Simple Solar Radiation Index for Wildlife Habitat Studies

Abstract: Solar radiation is a potentially important covariate in many wildlife habitat studies, but it is typically addressed only indirectly, using problematic surrogates like aspect or hillshade. We devised a simple solar radiation index (SRI) that combines readily available information about aspect, slope, and latitude. Our SRI is proportional to the amount of extraterrestrial solar radiation theoretically striking an arbitrarily oriented surface during the hour surrounding solar noon on the equinox. Because it derives from first geometric principles and is linearly distributed, SRI offers clear advantages over aspect-based surrogates. The SRI also is superior to hillshade, which we found to be sometimes imprecise and ill-behaved. To illustrate application of our SRI, we assessed niche separation among 3 ungulate species along a single environmental axis, solar radiation, on the northern Yellowstone winter range. We detected no difference between the niches occupied by bighorn sheep (Ovis canadensis) and elk (Cervus elaphus; P = 0.104), but found that mule deer (Odocoileus hemionus) tended to use areas receiving more solar radiation than either of the other species (P < 0.001). Overall, our SRI provides a useful metric that can reduce noise, improve interpretability, and increase parsimony in wildlife habitat models containing a solar radiation component.     

Freeze Thaw: A Simple Approach for Prediction of Optimal Cryoprotectant for Freeze Drying

The present study evaluates freeze thaw as a simple approach for screening the most appropriate cryoprotectant. Freeze–thaw study is based on the principle that an excipient, which protects nanoparticles during the first step of freezing, is likely to be an effective cryoprotectant. Nanoparticles of rifampicin with high entrapment efficiency were prepared by the emulsion-solvent diffusion method using dioctyl sodium sulfosuccinate (AOT) as complexing agent and Gantrez AN-119 as polymer. Freeze–thaw study was carried out using trehalose and fructose as cryoprotectants. The concentration of cryoprotectant, concentration of nanoparticles in the dispersion, and the freezing temperature were varied during the freeze–thaw study. Cryoprotection increased with increase in cryoprotectant concentration. Further, trehalose was superior to fructose at equivalent concentrations and moreover permitted use of more concentrated nanosuspensions for freeze drying. Freezing temperature did not influence the freeze–thaw study. Freeze-dried nanoparticles revealed good redispersibility with a size increase that correlated well with the freeze–thaw study at 20% w/v trehalose and fructose. Transmission electron microscopy revealed round particles with a size ∼400 nm, which correlated with photon correlation spectroscopic measurements. Differential scanning calorimetry and X-ray diffraction suggested amorphization of rifampicin. Fourier transfer infrared spectroscopy could not confirm interaction of drug with AOT. Nanoparticles exhibited sustained release of rifampicin, which followed diffusion kinetics. Nanoparticles of rifampicin were found to be stable for 12 months. The good correlation between freeze thaw and freeze drying suggests freeze–thaw study as a simple and quick approach for screening optimal cryoprotectant for freeze drying.     

A Simple Method for Multiple Modification of the Escherichia coli K-12 Chromosome

We developed a simple method of generating markerless deletions in the Escherichia coli chromosome. The method consists of two recombination events stimulated by λ Red recombinase. The first recombination replaced a target region with a marker cassette and the second then eliminated the marker cassette. The marker cassette included an antibiotic resistant gene and a negative selection marker (Bacillus subtilis sacB). Since sacB makes E. coli sensitive to sucrose, a markerless deletion strain was successfully selected using its sucrose-resistant phenotype. To stimulate these recombination events, 1-kbp homologous sequences adjacent to the target region were connected to both ends of the marker cassette or connected to each other by PCR. The average efficiency of the recombinations was 24% and 93% respectively. Eliminating the marker cassette with a fragment including an additional sequence, insertion was also possible. This markerless deletion method should be useful in creating a highly modified E. coli chromosome.     

SARS冠状病毒S蛋白结构预测及表达初探

利用生物信息学的工具和方法,对SARS病毒基因组中预测的S蛋白（spike protein）的编码序列进行了分析,预测了其结构特征和可能的功能域。选择其中最有可能参与受体识别及产生主要免疫原性的区域(S401～659)作为待表达区域。将通过PCR获得的此段S蛋白片段的编码序列克隆至大肠杆菌载体pET28a(+)和酵母表达载体pPIC9K中,分别构建了pET28a(+)-S和pPIC9K-S表达质粒,转化至大肠杆菌菌株BL21(DE3)-star和毕赤酵母中表达。产物的蛋白电泳和蛋白印记结果表明,S蛋白片段获得成功表达。采用镍离子螯合层析法纯化变性的包涵体样品,纯度达90%以上。