Assessment of long term outcomes after buccal mucosal graft urethroplasty: the impact of chronic kidney disease.

OBJECTIVES: To compare and assess various outcomes and success of buccal mucosal graft urethroplasty (BMGU) in patients with CKD versus patients having normal renal function. MATERIAL AND METHODS: This was a retrospective, single centre study, during period 2013 to 2017. Patients were grouped into two groups. Group 1 had patients with estimated Glomerular Filtration Rate (eGFR)>60mL/min/1.73m2 while group 2 had patients with eGFR <60mL/min/1.73m2. eGFR was calculated according to the MDRD equation. The two groups were compared with regard to various outcomes like length, location of stricture, technique of graft placement, intra-operative blood loss (haemoglobin drop), duration of hospital stay, post-operative complications and recurrence. RESULTS: A total of 223 patients were included in study with group 1 had 130 patients and group 2 had 93 patients. Mean age of patients with CKD were higher (47.49 years versus 29.13 years). The mean follow-up period was comparable between both groups (23.29 months and 22.54 months respectively). Patients with CKD had more post-operative Clavien Grade 2 or higher complications (p=0.01) and a greater recurrence rates (p<0.001) than in non-CKD patients. On multivariate analysis, age and CKD status was significant predictor of urethroplasty success (p=0.004) (OR= 14.98 (1.952-114.94, 95% CI). CONCLUSIONS: CKD patients are more prone to post-operative complications in terms of wound infection, graft uptake and graft failure and higher recurrence rates following BMGU.

Management of long segment anterior urethral stricture (≥ 8cm) using buccal mucosal (BM) graft and penile skin (PS) flap: outcome and predictors of failure.

PURPOSE: To evaluate the surgical outcome and predictors of failure of substitution urethroplasty using either dorsal onlay buccal mucosal (BM) graft or ventral onlay penile skin flap (PS) for anterior urethral stricture ≥ 8cm. PATIENTS AND METHODS: Between March 2010 and January 2016, 50 patients with anterior urethral stricture ≥ 8 cm were treated at our hospital. The surgical outcome and success rate were assessed. The predictors of failure were analyzed using multivariate analysis. Failure was considered when subsequent urethrotomy or urethroplasty were needed. RESULTS: Dorsal onlay BM graft was carried out in 24 patients, while PS urethroplasty in 26 patients. There was no significant difference between both groups regarding patients demographics, stricture characteristics or follow-up period. One case in the BM group was lost during follow- up. Stricture recurrence was detected in 7 (30.4%) patients out of BM group while in 6 (23.1%) patients out of PS group (p value= 0.5). No significant differences between both groups regarding overall early and late complications were observed. Occurrence of early complications and the stricture length were the only predictors of failure in univariate analysis, while in multivariate analysis the occurrence of early complications was only significant. CONCLUSION: On short-term follow-up, both dorsal onlay BM graft and ventral onlay PS flap urethroplasty have similar success rates. However, BM graft has a potential advantage to reduce operative time and is also technically easier. The surgeon should avoid early local complications as they represent a higher risk for failure.

[Improvement of Intestinal and Transmucosal Absorption of Peptide and Protein Drugs].

It is well known that the oral bioavailability of hydrophilic and macromolecular drugs is generally very poor due to their poor membrane permeability characteristics. Among these poorly absorbed drugs, peptide and protein drugs are typical poorly absorbed drugs which have low stability and poor permeability in the gastrointestinal tract. Consequently, the clinical administration of peptide and protein drugs is presently limited to administration by injection. However, such frequent administration subjects the patients to considerable pain, and there is also the possibility of the manifestation of serious side effects. Therefore, various approaches have been examined to overcome the poor absorption characteristics of these drugs. These approaches include (1) to use additives including absorption enhancers and protease inhibitors, (2) to modify the chemical structure of peptide and protein drugs, and (3) to apply dosage forms to these drugs, (4) to develop a novel administration method for these drugs that can serve as an alternative to oral and injection administration. We demonstrated that intestinal and transmucosal absorption of peptide and protein drugs could be improved by using these approaches. These approaches may give us useful basic information to improve the intestinal and transmucosal absorption of peptide and protein drugs.

Mucosal absorption of antibody drugs enhanced by cell-penetrating peptides anchored to a platform of polysaccharides.

Our previous studies demonstrated that L-octaarginine grafted onto hyaluronic acid via a tetraglycine spacer significantly enhanced intranasal absorption of protein drugs with a molecular weight (Mw) of 22 kDa or less. The present study focused on its potential as an absorption enhancer for antibody drugs with a larger Mw and the enhancement mechanism. When ranibizumab (48 kDa) alone was intranasally administered in mice, its absolute bioavailability was 0.67% on average. The mean bioavailability elevated to 6.2% under coadministration with tetraglycine-L-octaarginine-linked hyaluronic acid. A similar result was observed under substitution of ranibizumab with certolizumab pegol (91 kDa), although bioavailability itself decreased with the Mw increase, irrespective of coadministration with the hyaluronic acid derivative. Rat experiments also revealed that coadministration with the polysaccharide derivative resulted in significant enhancement of intranasal absorption of trastuzumab (148 kDa). In vitro studies using gene-knocked down cells indicated that syndecan-4-induced macropinocytosis played a crucial role on acceleration of antibody uptake into epithelial cells on the nasal mucosa, irrespective of their Mw. It appeared that neither clathrin heavy chain nor caveolin-1 involved in cellular uptake of antibodies. Tetraglycine-L-octaarginine-linked hyaluronic acid was concluded to be a promising delivery tool that possessed universal absorption-enhancing abilities independent to Mw of biologics.

Genomic Instability in Exfoliated Buccal Cells among Cement Warehouse Workers.

BACKGROUND: Workers in cement warehouses of Kerala are enduring long-standing exposure to cement dust, which is considered genotoxic. OBJECTIVE: To evaluate the extent of genotoxicity and cytotoxicity caused due to exposure of cement dust among those working in cement warehouses. METHODS: The study included 82 cement warehouse workers and 82 age-matched individuals with no exposure to cement dust. Exfoliated buccal micronucleus cytome assay (BMCyt) was performed to analyze the genotoxic and cytotoxic effects caused by inhalation of cement dust. RESULTS: The frequency of various genotoxic and cytotoxic end markers (micronucleated cells [2-fold increase, p<0.001], nuclear buds [4-fold increase, p<0.001], binucleated cells [4-fold increase, p<0.001], karyorrhectic cells [2-fold increase, p<0.001], pyknotic cells [3-fold increase, p<0.001], and karyolytic cells [2-fold increase, p<0.001]) were higher in the exposed workers compared with unexposed group. Increase of these parameters represented an increased level of chromosomal damage, nuclear disintegration and increased cell death among exposed group compared with unexposed group. CONCLUSION: Continuous exposure to cement dust results in increased frequency of nuclear aberrations and cellular apoptosis. This may lead to defects in genome maintenance, accelerated ageing, increased chance of oral cancer and neurodegenerative disorders in those occupationally exposed to cement dust.

Quantitative estimation of drug permeation through nasal mucosa using in vitro membrane permeability across Calu-3 cell layers for predicting in vivo bioavailability after intranasal administration to rats.

For establishing a precise system for predicting in vivo bioavailability following intranasal (IN) administration, the relationships among membrane permeability of drugs across Calu-3 cells, in situ nasal mucosal drug permeation rate, and in vivo drug absorption following IN administration were quantified. The membrane permeability coefficient (Papp) was determined for sixteen model drugs by in vitro permeation studies in Calu-3 cells. The drug permeation rate constant through the nasal mucosa (kn) was calculated from the in situ nasal perfusion of the drug solutions in rats. Bioavailability following IN administration of six model drugs with different membrane permeabilities were determined by in vivo drug absorption studies in rats. The correlations among in vitro membrane permeability properties, in situ nasal mucosal drug permeation rate, and in vivo drug absorption following IN administration, were assessed. The significant correlation between the in vitro Calu-3 cell permeability and nasal mucosal drug permeation rate (r2 = 0.812, p < 0.001) indicated that nasal mucosal drug permeability is estimable from in vitro membrane permeability. Furthermore, bioavailability following IN administration significantly correlated with the in vitro Papp across Calu-3 cells (r2 = 0.984, p < 0.001), suggesting that in vivo drug absorption following IN administration can be predicted from in vitro Calu-3 membrane permeability.

Oromucosal drug delivery: Trends in in-vitro biopharmaceutical assessment of new chemical entities and formulations.

Development of buccal application forms is gaining increasing interest in recent years, mostly driven by the insight that enabling formulations may help to overcome limitations as well as the need for patient-oriented medicines. A key characteristic of dosage forms is whether they can grant absorption of therapeutically relevant doses across the limited absorption area in the mouth and realistic time window. Despite the generally accepted paradigm to replace or at least reduce animal experiments, current transport studies towards oromucosal drug delivery still are dominated by in vivo or ex vivo animal studies. Only few groups have published pioneering transport experiments with alternative models avoiding the use of animals. The few studies indicate that there is increasing justification for the use of artificial membranes to replace the classical cell- and tissue-based systems. The artificial membranes need to be biomimetic and distinguish transport kinetics of dissociation states and molecule flexibility. It appears that dissociation states may be distinguished by silicone membranes, as well as by phospholipid based models (PAMPA variants and Permeapad®). Regarding other molecule properties such as flexibility, data are available demonstrating excellent IVIVR. Aim of the current review is to make the scientific community dealing with oromucosal drug formulation development aware of the opportunities provided by non-cellular artificial membranes.

The relationship between in vivo nasal drug clearance and in vitro nasal mucociliary clearance: Application to the prediction of nasal drug absorption.

Drug absorption after nasal application is dependent on drug clearance from the nasal cavity, which is determined by nasal mucociliary clearance (MC). We previously developed an in vitro method to evaluate MC via the translocation velocity of fluorescent microspheres (VFMS) applied to excised rat nasal mucosa. In the present study, the relationship between in vivo nasal MC and in vitro VFMS was examined to optimize our PK model for the prediction of nasal drug absorption. Appropriate inhibitors (propranolol and atropine) and enhancers (terbutaline and acetylcholine chloride) of MC were utilized to modify MC. In vivo clearance of drug from the nasal cavity was determined from the disappearance of fluorescent microspheres (FMS) from the nasal cavity following nasal application to rats. The first order elimination rate constant, kmc, was determined from the disappearance profiles of FMS. kmc was decreased to 35.8% by propranolol and 52.6% by atropine, but increased to 117% by terbutaline and 168% by acetylcholine chloride. A significant linear correlation was observed between kmc and VFMS (r2 = 0.9745, p < 0.001). These results indicate that in vivo kmc can be estimated from the in vitro parameter, VFMS. By introducing linear correlation into our PK model, nasal drug absorption may be precisely estimated, even with changes in MC.

Angubindin-1, a novel paracellular absorption enhancer acting at the tricellular tight junction.

A limiting barrier for mucosal absorption of drugs is the tight junction (TJ). TJs exist between two adjacent cells (bicellular TJ, bTJ) and at the sites where three cells meet (tricellular TJ, tTJ). We present a novel approach which employs a physiologically regulated pathway for the passage of large molecules through the tTJ. Main barrier-relevant tTJ proteins are tricellulin and angulin-1 to -3. We developed an angulin binder from Clostridium perfringens iota-toxin (Ib) whose receptor is angulin-1. An Ib fragment corresponding to amino acids 421-664 (Ib421-664) of iota-toxin proved to bind in cells expressing angulin-1 and -3, but not angulin-2. This binding led to removal of angulin-1 and tricellulin from the tTJ which enhanced the permeation of macromolecular solutes. Ib421-664 enhanced intestinal absorption in rats and mice. Our findings indicate that Ib421-664, which we designate angubindin-1, is a modulator of the tTJ barrier and that modulation of that barrier qualifies for a new strategy of developing a mucosal absorption enhancer.

Assessment of long term outcomes after buccal mucosal graft urethroplasty: the impact of chronic kidney disease

ABSTRACT Objectives To compare and assess various outcomes and success of buccal mucosal graft urethroplasty (BMGU) in patients with CKD versus patients having normal renal function. Material and Methods This was a retrospective, single centre study, during period 2013 to 2017. Patients were grouped into two groups. Group 1 had patients with estimated Glomerular Filtration Rate (eGFR)>60mL/min/1.73m2 while group 2 had patients with eGFR <60mL/min/1.73m2. eGFR was calculated according to the MDRD equation. The two groups were compared with regard to various outcomes like length, location of stricture, technique of graft placement, intra-operative blood loss (haemoglobin drop), duration of hospital stay, post-operative complications and recurrence. Results A total of 223 patients were included in study with group 1 had 130 patients and group 2 had 93 patients. Mean age of patients with CKD were higher (47.49 years versus 29.13 years). The mean follow-up period was comparable between both groups (23.29 months and 22.54 months respectively). Patients with CKD had more post-operative Clavien Grade 2 or higher complications (p=0.01) and a greater recurrence rates (p<0.001) than in non-CKD patients. On multivariate analysis, age and CKD status was significant predictor of urethroplasty success (p=0.004) (OR= 14.98 (1.952-114.94, 95% CI). Conclusions CKD patients are more prone to post-operative complications in terms of wound infection, graft uptake and graft failure and higher recurrence rates following BMGU.

Management of long segment anterior urethral stricture (≥ 8cm) using buccal mucosal (BM) graft and penile skin (PS) flap: outcome and predictors of failure

ABSTRACT Purpose To evaluate the surgical outcome and predictors of failure of substitution urethroplasty using either dorsal onlay buccal mucosal (BM) graft or ventral onlay penile skin flap (PS) for anterior urethral stricture ≥ 8cm. Patients and methods Between March 2010 and January 2016, 50 patients with anterior urethral stricture ≥ 8 cm were treated at our hospital. The surgical outcome and success rate were assessed. The predictors of failure were analyzed using multivariate analysis. Failure was considered when subsequent urethrotomy or urethroplasty were needed. Results Dorsal onlay BM graft was carried out in 24 patients, while PS urethroplasty in 26 patients. There was no significant difference between both groups regarding patients demographics, stricture characteristics or follow-up period. One case in the BM group was lost during follow-up. Stricture recurrence was detected in 7 (30.4%) patients out of BM group while in 6 (23.1%) patients out of PS group (p value= 0.5). No significant differences between both groups regarding overall early and late complications were observed. Occurrence of early complications and the stricture length were the only predictors of failure in univariate analysis, while in multivariate analysis the occurrence of early complications was only significant. Conclusion On short-term follow-up, both dorsal onlay BM graft and ventral onlay PS flap urethroplasty have similar success rates. However, BM graft has a potential advantage to reduce operative time and is also technically easier. The surgeon should avoid early local complications as they represent a higher risk for failure.