An animal experimental study on pubourethral ligament restoration with platelet rich plasma for the treatment of stress urinary incontinence.

Introduction: Minimally invasive methods for injured ligament and tendon restoration have been developed and gained popularity in recent years. Injury and relaxation of the pubourethral ligament (PUL) can lead to stress urinary incontinence (SUI). The aim of this study was to investigate the impact of injecting platelet rich plasma (PRP) into the PUL following its surgical transection resulting in SUI, confirmed by leak point pressure (LPP) measurements pre- and post-intervention in an experimental animal model. Material and methods: Twenty female adult Sprague-Dawley rats were assigned in 2 groups: 1) treatment group with transection of the PUL and application of PRP at the time of transection and at one month follow-up and 2) a control group, with transection of the PUL only. Leak point pressures (LPPs) were measured prior to transection, immediately following the transection and at 1 and 2 months in both groups. Results: The median LPPs for the control group were: LPP - preT: 35.6 (29.8-44.8) cmH2O, LPP - postT: 14.6 (5.8-19.0) cmH2O, LPP - 1 month: 27.3 (19.2-33.8) cmH2O, LPP - 2 months: 29.0 (27.0-34.0) cmH2O, whereas for the PRP group were: LPP-preT: 40.5 (33.2-46.3) cmH2O, LPP - postT: 15.7 (3.0-24.0) cmH2O, LPP - 1month: 31.6 (24.8-37.4) cmH2O, LPP - 2 months: 36.8 (32.5-45.4) cmH2O. PRP injections on transected PULs significantly increased LPPs at one month follow-up [31.6 cmH2O vs. 27.3 cmH2O, p = .043]. This effect was confirmed at two months [36.8 cmH2O vs. 29.0 cmH2O, p <.001]. Conclusions: Injection of PRP into transected PULs significantly improved LPPs at one and two months' follow-up. However, further experimental and clinical research is needed to evaluate the safety and efficacy of this treatment, in clinical practice

The fracture stress of rat achilles tendons

For the determination of the fracture stress of soft tissues both the fracture force and the cross sectional  area are required. For short tissues these prerequisites are difficult experimental tasks. The determination  of the fracture force necessitates proper gripping without damaging the tissues or altering their properties.  In order to meet this challenge the rapid-freezing technique was employed, modified to ensure that the  tendon was not frozen. On the other hand an accurate value of the cross sectional area of short soft tissues  is difficult to be obtained using conventional techniques. In this context a novel procedure is proposed here  based on the histologically-measured cross-sectional area of the dehydrated tendon after the biomechanical  testing. Combination of these solutions permitted the performance of tension tests for rat Achilles tendons  and calculation of their fracture stress. The values of the Achilles tendon failure stress, as estimated above,  exhibited considerably lower scattering compared to those of the fracture forces.

A research model of measuring the tensile strength of colonic anastomosis in Wistar rats

The present experimental study investigates the mechanical behavior of intestinal anastomoses in  Wistar rats. More specifically the response of the anastomoses to a properly applied uniaxial direct  tensile load is studied and the respective tensile strength is determined. The surgical procedure of large  bowel anastomoses is described in detail. In addition the authors provide a thorough description of  the experimental apparatus, designed especially for measuring the tensile strength of the specimens  under study, with special consideration in gripping of the intestine, the load application and the data  acquisition and storage systems. This experimental model provides an excellent method for measuring the  anastomotic strength and therefore a flexible tool for the comparative evaluation of various anastomotic  techniques.

Effect of oral contraceptive treatment on bone mass acquisition in skeletally immature young female rats

The objective of the present study was to investigate the effect of oral contraceptive (OC) treatment on bone mass accrual in skeletally immature young female rats. Animals in the baseline group were killed at the beginning of the experiment and were subjected to bone density assessment by peripheral quantitative computerized tomogmphy (pQCT). The control group was fed a base diet free of phytoestrogens, while animals in the contraceptive group received the same base diet mixed with 2.67 mu g desogestrel/100 g body weight and 0.0533 mu g ethinyl estradiol/100 g body weight. The duration of the treatment period was 16 weeks. Densitometric measurements by dual energy x-ray absorptiometry and serum bone markers assessment were carried out at baseline, at 8 weeks and at 16 weeks, while pQCT densitometry took place after sacrifice. All bone mineral density and bone mineral content indices measured by dual energy x-ray absorptiometry increased significantly throughout the study period in both the OC and control group. Concerning pQCT measurements, animals in both the OC and the control group had significantly higher cortical density compared with baseline (midtibia: p=.0003 and .0003, respectively). Total area and periosteal circumference were significantly higher in OC group, both in proximal (p=.003 and .003, respectively) and midtibia (P=.048 and .042, respectively) compared with baseline. Osteoprotegerin serum levels increased in both groups, and at the end of the experiment, circulating osteoprotegerin was significantly higher in the OC group compared with controls (p=.032). At the end of the experiment, carboxyl-terminal telopeptides of collagen type I levels were significantly lower in the OC-treated animals compared with controls (p=.046). Our results suggest that OC administration to skeletally immature female rats allows normal bone accrual and may even improve bone geometry. This effect may be mediated through enhanced inhibition of bone resorption. (c) 2005 Elsevier Inc. All rights reserved