Prefabricated partial distal urethral in 2-staged repair of proximal hypospadias with severe chordee.

PURPOSE: To describe a new technique for staged hypospadias repair in which the urethral plate is divided and tubularized transverse island flap prefabricated partial distal urethral at the time of the first stage. MATERIALS AND METHODS: Sixteen patients with proximal hypospadias associated with severe chordee were operated on using a new staged technique. At the time of the first stage, the urethral plate was divided and chordee was corrected. Then tubularized transverse island flap was used to prefabricate partial distal urethra. The defective urethra was repaired using the Thiersch-Duplay principle at the second stage. RESULTS: All participants have completed both stages of the operation. The mean follow-up duration was 18.4 months (range from 6 to 72 months). In the first-stage surgery, the modified tabularized transverse preputial island flap was performed on 6 patients, whereas the modified preputial double-faced island flap was performed on the other 10 patients. All of the prefabricated partial distal neourethras had no evidence of stenosis or scarring. The result of the second-stage procedure was a complete penis with integrated urethral. All patients were satisfied with cosmetic and functional results. Neither stricture nor diverticula was observed. A good urinary stream during the urination was attained in 12 (75.0%) patients. Four cases (25.0%) developed urethrocutaneous fistula after the second stage repair. CONCLUSIONS: In our preliminary series, this procedure improved functional and cosmetic results. It may be applicable to most cases of proximal hypospadias. Even when complications occur, they are less severe compared to those of the traditional staged approach.

Building large collections of Chinese and English medical terms from semi-structured and encyclopedia websites.

To build large collections of medical terms from semi-structured information sources (e.g. tables, lists, etc.) and encyclopedia sites on the web. The terms are classified into the three semantic categories, Medical Problems, Medications, and Medical Tests, which were used in i2b2 challenge tasks. We developed two systems, one for Chinese and another for English terms. The two systems share the same methodology and use the same software with minimum language dependent parts. We produced large collections of terms by exploiting billions of semi-structured information sources and encyclopedia sites on the Web. The standard performance metric of recall (R) is extended to three different types of Recall to take the surface variability of terms into consideration. They are Surface Recall (R(S)), Object Recall (R(O)), and Surface Head recall (R(H)). We use two test sets for Chinese. For English, we use a collection of terms in the 2010 i2b2 text. Two collections of terms, one for English and the other for Chinese, have been created. The terms in these collections are classified as either of Medical Problems, Medications, or Medical Tests in the i2b2 challenge tasks. The English collection contains 49,249 (Problems), 89,591 (Medications) and 25,107 (Tests) terms, while the Chinese one contains 66,780 (Problems), 101,025 (Medications), and 15,032 (Tests) terms. The proposed method of constructing a large collection of medical terms is both efficient and effective, and, most of all, independent of language. The collections will be made publicly available.

Suicide note sentiment classification: a supervised approach augmented by web data.

OBJECTIVE: To create a sentiment classification system for the Fifth i2b2/VA Challenge Track 2, which can identify thirteen subjective categories and two objective categories. DESIGN: We developed a hybrid system using Support Vector Machine (SVM) classifiers with augmented training data from the Internet. Our system consists of three types of classification-based systems: the first system uses spanning n-gram features for subjective categories, the second one uses bag-of-n-gram features for objective categories, and the third one uses pattern matching for infrequent or subtle emotion categories. The spanning n-gram features are selected by a feature selection algorithm that leverages emotional corpus from weblogs. Special normalization of objective sentences is generalized with shallow parsing and external web knowledge. We utilize three sources of web data: the weblog of LiveJournal which helps to improve the feature selection, the eBay List which assists in special normalization of information and instructions categories, and the suicide project web which provides unlabeled data with similar properties as suicide notes. MEASUREMENTS: The performance is evaluated by the overall micro-averaged precision, recall and F-measure. RESULT: Our system achieved an overall micro-averaged F-measure of 0.59. Happiness_peacefulness had the highest F-measure of 0.81. We were ranked as the second best out of 26 competing teams. CONCLUSION: Our results indicated that classifying fine-grained sentiments at sentence level is a non-trivial task. It is effective to divide categories into different groups according to their semantic properties. In addition, our system performance benefits from external knowledge extracted from publically available web data of other purposes; performance can be further enhanced when more training data is available.

A classification approach to coreference in discharge summaries: 2011 i2b2 challenge.

OBJECTIVE: To create a highly accurate coreference system in discharge summaries for the 2011 i2b2 challenge. The coreference categories include Person, Problem, Treatment, and Test. DESIGN: An integrated coreference resolution system was developed by exploiting Person attributes, contextual semantic clues, and world knowledge. It includes three subsystems: Person coreference system based on three Person attributes, Problem/Treatment/Test system based on numerous contextual semantic extractors and world knowledge, and Pronoun system based on a multi-class support vector machine classifier. The three Person attributes are patient, relative and hospital personnel. Contextual semantic extractors include anatomy, position, medication, indicator, temporal, spatial, section, modifier, equipment, operation, and assertion. The world knowledge is extracted from external resources such as Wikipedia. MEASUREMENTS: Micro-averaged precision, recall and F-measure in MUC, BCubed and CEAF were used to evaluate results. RESULTS: The system achieved an overall micro-averaged precision, recall and F-measure of 0.906, 0.925, and 0.915, respectively, on test data (from four hospitals) released by the challenge organizers. It achieved a precision, recall and F-measure of 0.905, 0.920 and 0.913, respectively, on test data without Pittsburgh data. We ranked the first out of 20 competing teams. Among the four sub-tasks on Person, Problem, Treatment, and Test, the highest F-measure was seen for Person coreference. CONCLUSIONS: This system achieved encouraging results. The Person system can determine whether personal pronouns and proper names are coreferent or not. The Problem/Treatment/Test system benefits from both world knowledge in evaluating the similarity of two mentions and contextual semantic extractors in identifying semantic clues. The Pronoun system can automatically detect whether a Pronoun mention is coreferent to that of the other four types. This study demonstrates that it is feasible to accomplish the coreference task in discharge summaries.

The short- and medium-term results of transcatheter closure of atrial septal defect with severe pulmonary arterial hypertension.

We investigated the short-term and medium-term results in patients with pulmonary arterial hypertension (PAH) associated with atrial septal defect (ASD) undergoing transcatheter closure. Fifteen patients with severe PAH associated with ASD who underwent successful occluder implantation from 2007 to 2010 were included. Clinical, echocardiographic, and hemodynamic data were reviewed. Severe PAH was defined as pulmonary arterial systolic pressure measured by catheterization was ≥60 mmHg and pulmonary vascular resistance (PVR) ≥6 Wood Units (WU). Compared with baseline, the 6-minwalking distance significantly increased by 29.7 ± 26.3 m (P < 0.001) at 3 months (short-term) and 65.4 ± 63.6 m (P < 0.001) at 23.4 ± 9.7 months (medium-term), World Health Organization function class considerably improved after postclosure short-term and medium-term. Repeat cardiac catheterization (n = 7) showed that mean pulmonary arterial pressure decreased from 51.6 ± 9.4 mmHg at baseline to 21.0 ± 3.8 mmHg (P < 0.001) at follow-up of 12 months. The PVR decreased by 5.6 ± 1.1 WU (P < 0.001). Through carefully selected patients with severe PAH associated with ASD, transcatheter closure can be safely performed with a promising short-term and medium-term outcome. Trial occlusion is an effective way for deciding the reversibility of severe PAH in ASD patients. The role of aerosolized iloprost for pulmonary vasoreactivity testing in patients with severe PAH secondary to ASD requires further investigation.

[Gene profiling after knocking-down the expression of NS gene in prostate cancer PC-3 cells].

OBJECTIVE: To screen the genes and possible signal transduction pathways involved in the mechanism of nucleostemin (NS) in the proliferation of prostate cancer. METHODS: Oligonucleotide DNA microarray was used to screen the genome changes after knocking-down expression of NS in PC-3 cells and quantitative real-time PCR was used to further confirm the important differentially expressed genes. RESULTS: 219 differentially expressed genes were found and theses genes were involved in cell cycle, cell proliferation, signal transduction, cell apoptosis and cell differentiation, etc. INK4 family genes (p15, p16, p18) were up-regulated and cyclin D1, HDAC1 were down-regulated, the main action points were CDK4/6-cyclin D and pRb-E2F1 complexes. CONCLUSION: NS may promote the progression of prostate cancer by inhibiting the expression of p15, p16, and p18 in PC-3 cells. NS is an important G(1)/S checkpoint regulator and its regulatory activity has been certified at gene level.

[Silencing nucleostemin expression reduces the proliferation of PC-3 cells].

OBJECTIVE: To detect the expression of the nucleostemin (NS) gene in prostate cancer PC-3, LNCaP and DU145 cells, and to study the effect of the NS gene on the proliferation of PC-3 cells after its silencing. METHODS: The protein and mRNA expressions of NS in PC-3, LNCaP and DU145 cells were respectively detected by immunohistochemical staining and RT-PCR. An NS-specific short-hairpin RNA (shRNA) expression plasmid was used to transfect the PC-3 cells (NS-shRNA-PC-3), followed by observation of the changes of the NS gene and the proliferation and apoptosis of the cells. RESULTS: The NS gene was highly expressed in the three types of cells. After the transfection, the NS expression and the proliferation of the NS-siRNA-PC-3 cells were remarkably reduced, while the percentage of the GO/G1 cells and the early apoptosis of the PC-3 cells obviously increased. A marked decrease was observed in the neoplasm forming ability of the NS-siRNA-PC-3 cells in the nude mice. CONCLUSION: NS is highly expressed in prostate cancer cells. The proliferation of PC-3 cells is remarkably reduced and the early apoptosis of PC-3 cells increased after silencing the NS gene by NS-specific shRNA.

[Expression of nucleostemin in prostate cancer tissues and its clinical significance].

OBJECTIVE: To explore the expression of the nucleostemin (NS) gene in prostate cancer (PCa) tissues and its clinical significance. METHODS: We detected the NS expression in PCa, benign prostatic hyperplasia (BPH) and high grade prostatic intraepithelial neoplasia (HGPIN) tissues by RT-PCR and immunohistochemistry, and analyzed the correlation between the expression of the NS protein and the clinical variables of PCa. RESULTS: The NS mRNA level was markedly higher in the PCa than in the BPH tissues. The rates of strongly positive, positive and weakly positive expressions of the NS protein were 48.8%, 36.6% and 12.2% in PCa, 4.0%, 32.0% and 56.0% in BPH, and 5.0%, 25.0% and 60.0% in HGPIN, respectively. The expression level of the NS protein was significantly higher in PCa than in BPH and HGPIN (P < 0.05). The expression of the NS gene was negatively correlated with the degree of cell differentiation in the PCa tissues, the worse the differentiation, the higher the NS expression level. CONCLUSION: The NS gene is highly expressed in PCa tissues and may have an important role in the adverse differentiation and malignant proliferation of prostate cancer.