In pressure/flow studies of adult voiding the behaviour of the urethra can be distinguished from that of the bladder, and quantified separately, as follows. Different degrees of urethral obstruction can be quantified and ranked using a group-specific resistance factor (URA) that is based empirically on the pressure/flow plots obtained in a large number of voidings of adult patients. Different detrusor contractions can be similarly quantified using a physiologically based measure (WF, abbreviated from power [W] factor) of the contraction strength. Both URA and WF can be calculated by computer from measurements of detrusor pressure, voiding flow rate, and the residual volume in the bladder after voiding. For other groups of patients, e.g., children, different group-specific resistance factors are appropriate.In men with obstructed voiding due to benign prostatic hyperplasia (BPH), "chemical castration" with cyproterone acetate or buserelin caused a substantial, reversible reduction in the size of the prostate. The effect on the degree of urethral obstruction and the voiding bladder contraction has been studied using the above-mentioned methods. There was an increase in peak urinary flow rate, a reduction in residual urine, and a decrease in daytime voiding frequency. Surprisingly, however, there was on average no decrease in urethral resistance but only an increase in the average detrusor contraction strength. In individual patients large increases and decreases of urethral resistance and detrusor contraction strength occurred, which largely cancelled each other out. These large changes masked the relatively modest urethral resistance decrease caused directly by prostate size reduction.
BackgroundTechniques to treat urethral stricture and hypospadias are restricted, as substitution of the unhealthy urethra with tissue from other origins (skin, bladder or buccal mucosa) has some limitations. Therefore, alternative sources of tissue for use in urethral reconstructions are considered, such as ex vivo engineered constructs.PurposeTo review recent literature on tissue engineering for human urethral reconstruction.MethodsA search was made in the PubMed and Embase databases restricted to the last 25 years and the English language.ResultsA total of 45 articles were selected describing the use of tissue engineering in urethral reconstruction. The results are discussed in four groups: autologous cell cultures, matrices/scaffolds, cell-seeded scaffolds, and clinical results of urethral reconstructions using these materials. Different progenitor cells were used, isolated from either urine or adipose tissue, but slightly better results were obtained with in vitro expansion of urothelial cells from bladder washings, tissue biopsies from the bladder (urothelium) or the oral cavity (buccal mucosa). Compared with a synthetic scaffold, a biological scaffold has the advantage of bioactive extracellular matrix proteins on its surface. When applied clinically, a non-seeded matrix only seems suited for use as an onlay graft. When a tubularized substitution is the aim, a cell-seeded construct seems more beneficial.ConclusionsConsiderable experience is available with tissue engineering of urethral tissue in vitro, produced with cells of different origin. Clinical and in vivo experiments show promising results.
Study Type – Prognostic (case series) Level of Evidence 4
What’s known on the subject? and What does the study add?
Nowadays more and more publications have been published about the topic prostate cancer aggressiveness and obesity with mixed results. However, most of the publications used the BMI as a marker for obesity, while the most metabolic active fat is the visceral fat. To learn more about these relations we measured and used the visceral fat in our paper.
OBJECTIVE
• To examine if the periprostatic fat measured on computed tomography (CT) correlates with advanced disease we examined patients who received radiotherapy for localized prostate cancer. Several USA reports found a positive association between obesity and prostate cancer aggressiveness. However, in recent European studies these conclusions were not confirmed. Studies concerning this issue have basically relied on body mass index (BMI), as a marker of general obesity. Visceral fat, however, is the most metabolically active and best measured on CT.
PATIENTS AND METHODS
• In 932 patients, who were treated with external radiotherapy (N= 311) or brachytherapy (N= 621) for their T1‐3N0M0 prostate cancer, different fat measurements (periprostatic fat, subcutaneous fat thickness) were performed on a CT.
• Associations between the different fat measurements and risk of having high‐risk (according to Ash et al., PSA > 20 or Gleason score ≥8 or T3) disease was measured.
RESULTS
• The median age (IQR) was 67.0 years (62.0–71.0) and median BMI (IQR) was 25.8 (24.2–28.3). Logistic regression analyses, adjusted for age, revealed a significant association between periprostatic fat density (PFD) and risk of having a high risk disease. (Odds ratio [95% CI] 1.06 [1.04–1.08], P < 0.001)
CONCLUSION
• Patients with a higher PFD had more often aggressive prostate cancer.
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