The use of a modified tanagho flap in the repair of posterior urethral stricture after primary exstrophy closure.

INTRODUCTION: In patients with classic bladder exstrophy (CBE), posterior urethral strictures after primary bladder closure can be difficult to manage and therefore necessitate alternative techniques in reconstruction of the proximal urethra. There is a paucity of literature describing treatment and management of posterior urethral stricture arising after repair of classic bladder exstrophy. OBJECTIVE: To describe the technique of a bladder neck reconstruction (BNR) with a modified Tanagho anterior detrusor flap in the treatment of posterior urethral stricture arising after repair of classic bladder exstrophy. PATIENTS AND METHODS: A prospectively maintained, IRB-approved database of 1401 exstrophy-epispadias patients was reviewed for patients who underwent bladder neck or proximal urethral reconstruction with modified Tanagho flap for proximal urethral stricture disease from the time period of 1975-2021. A total of 5 patients (1 female and 4 males) with classic bladder exstrophy who underwent proximal urethral reconstruction with modified Tanagho flap were identified. Of these 5 patients, the 1 female patient was treated for ongoing incontinence, not posterior urethral stricture, and was thus excluded from this report. Outcomes measured included post operative bladder capacity, post-operative continence status, upper urinary tract status, and stricture recurrence. RESULTS: Four male patients with CBE were treated for posterior urethral strictures and are reviewed here. Three patients underwent successful primary closure (1 via modern staged repair of exstrophy (MSRE) and 2 via complete primary repair of exstrophy (CPRE)), and 1 patient (MSRE) required repeat closure at the time of stricture repair. Mean age at BNR Tanagho flap was 3.8 (range 2.3-5.0) years. All patients remained stricture free with post-operative urinary incontinence; 2 patients underwent subsequent elective bladder neck transection to achieve continence. Mean follow up 9.9 (range 2.1-15.6) years. DISCUSSION: All 4 patients had excellent long term success rates, comparable to results reported in several adult studies utilizing a modified Tanagho flap in women with post-traumatic bladder neck contractures. In addition, our technique described here shares similarities with both the originally described Tanagho flap as well as with a dorsal onlay graft urethroplasty. CONCLUSION: In this limited series, modified Tanagho flap reconstruction is effective in treating posterior urethral stricture disease in CBE. This technique adds a valuable adjunct to the armamentarium of surgical options for this difficult to manage condition.

Application of Correlation Pre-Filtering Neural Network to DNA Methylation Data: Biological Aging Prediction.

We introduce the CPFNN (Correlation Pre-Filtering Neural Network) for biological age prediction based on blood DNA methylation data. The model is built on 20,000 top correlated DNA methylation features and trained by 1810 healthy samples from GEO database. The input data format and the instructions for parser and CPFNN model are detailed in this chapter. Followed by two potential uses, age acceleration detection and unknown age prediction are discussed.

Age Prediction by DNA Methylation in Neural Networks.

Aging is traditionally thought to be caused by complex and interacting factors such as DNA methylation. The traditional formula of DNA methylation aging is based on linear models and little work has explored the effectiveness of neural networks, which can learn non-linear relationships. DNA methylation data typically consists of hundreds of thousands of feature space and a much less number of biological samples. This leads to overfitting and a poor generalization of neural networks. We propose Correlation Pre-Filtered Neural Network (CPFNN) that uses Spearman Correlation to pre-filter the input features before feeding them into neural networks. We compare CPFNN with the statistical regressions (i.e., Horvath's and Hannum's formulas), the neural networks with LASSO regularization and elastic net regularization, and the Dropout Neural Networks. CPFNN outperforms these models by at least 1 year in term of Mean Absolute Error (MAE), with a MAE of 2.7 years. We also test for association between the epigenetic age with Schizophrenia and Down Syndrome ( p=0.024 and , respectively). We discover that for a large number of candidate features, such as genome-wide DNA methylation data, a key factor in improving prediction accuracy is to appropriately weight features that are highly correlated with the outcome of interest.

Exploring the Link Between Platelet Numbers and Vascular Homeostasis Across Early and Late Stages of Fibrosis in Hepatitis C.

BACKGROUND: Thrombocytopenia is a hallmark of advanced liver disease. Platelets, growth factors (GFs), and vascular integrity are closely linked factors in disease pathogenesis, and their relationship, particularly in early disease stages, is not entirely understood. The aim was to compare circulating platelets, growth factors, and vascular injury markers (VIMs) in hepatitis C-infected (HCV) patients with early fibrosis and cirrhosis. METHODS: Retrospective evaluation of serum GFs and VIMs by ELISA were evaluated from twenty-six HCV patients. Analytes from an earlier time-point were correlated with MELD at a later time-point. RESULTS: Platelets and GFs decreased, and VIMs increased with fibrosis. Platelets correlated positively with PDGF-AA, PDGF-BB, TGFB1, EGF, and P-selectin, and negatively with ICAM-3 and VCAM-1. P-selectin showed no correlations with VIMs but positively correlated with PDGF-AA, PDGF-BB, TGFB1, and EGF. Soluble VCAM-1 and ICAM-3 were linked to increasing fibrosis, liver enzymes, and synthetic dysfunction. Higher VCAM-1 and ICAM-3 and lower P-selectin at an earlier time-point were linked to higher MELD score at a later time-point. CONCLUSION: In chronic HCV, progressive decline in platelets and growth factors with fibrosis and their associations suggest that platelets are an important source of circulating GFs and influence GF decline with fibrosis. Enhanced markers of vascular injury in patients with early fibrosis suggest an earlier onset of endothelial dysfunction preceding cirrhosis. Associations of VIMs with platelets suggest a critical link between platelets and vascular homeostasis. Circulating markers of vascular injury may not only have prognostic importance but emphasize the role of vascular dysfunction in liver disease pathogenesis (NCT00001971).

Bacterial Translocation and Host Immune Activation in Chronic Hepatitis C Infection.

Hepatitis C virus (HCV) infects 71 million individuals, and barriers to treatment remain. Bacterial translocation is a complication of chronic HCV infection, and this study evaluated circulating microbial components including lipopolysaccharide, peptidoglycan, and ß-D-glucan in addition to their pattern recognition receptors and degree of hepatic macrophage uptake. The findings suggest that regulation of serum peptidoglycan and ß-D-glucan differs from that of lipopolysaccharide. Additionally, macrophage activation in the liver may be better reflected by the degree of macrophage uptake than by circulating levels of microbial markers. These findings allow for a greater understanding of bacterial translocation and host immune activation during HCV infection.