• MeSH
• antivirové látky MeSH
• onkogenní viry účinky léků   MeSH
• skot MeSH
• suramin MeSH
• teoretické modely MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH

A mitral allograft is used exceptionally in the mitral, as well as in the tricuspid position, mostly as an experimental surgical procedure. The authors decided to evaluate the possibility of inserting a cryopreserved mitral allograft into the tricuspid position in a sheep experimental model. Within the framework of this experimental project the mechanical properties of the cryopreserved mitral allograft were tested. A novel methodology studying the functional unit composed of mitral annulus, leaflet, chordae tendinaea, and papillary muscle is presented. A five-parameter Maxwell model was applied to characterize the viscoelastic behavior of sheep mitral valves. A control group of 39 fresh mitral specimens and a test group of 13 cryopreserved mitral allografts from tissue bank were tested. The testing protocol consisted of six loading cycles with 1 mm elongation every 5 min. There was no significant difference in the mean values of the determined parameters (p>0.05) which confirms the main hypothesis that cryopreservation does not influence significantly material parameters characterizing the tissue mechanics. Slight discrepancy is observed in variances of viscous parameters suggesting that the values of the test group may be spread over larger interval due to the treatment.

• MeSH
• kryoprezervace MeSH
• mechanický stres MeSH
• mitrální chlopeň MeSH
• modely u zvířat MeSH
• ovce MeSH
• povrchové vlastnosti MeSH
• srdeční chlopně umělé MeSH
• trikuspidální chlopeň chirurgie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

Mitral allografts are still used only exceptionally in the mitral or tricuspid position. The main indication remains infectious endocarditis of atrioventricular valves for its flexibility and low risk of infection. The aim of our study was to evaluate 1-year results of mitral allografts transplantation into the tricuspid position in a sheep model. Mitral allografts were processed, cryopreserved, and transplanted into the tricuspid position anatomically (Group I - 11 animals) or antianatomically (Group II - 8 animals). All survivors (4 from Group I, and 3 from Group II) were checked at 3, 6, and 12 months by echocardiography with the exception of one survivor from Group II (which was examinated only visually). Examination throughout follow-up included for mitral allograft regurgitation and annuli dilatation. At postmortem, the papillary muscles were healed and firmly anchored to the right ventricular wall in all subjects. Transventricular fixation of the papillary muscles with buttressed sutures was proven to be a stable, reproducible, and safe method for anchoring mitral allograft leaflets. There were no significant differences between the two implantation methods. Annulus support of mitral allografts might be very useful in this type of operation and could prevent annular dilatation.

• MeSH
• alografty MeSH
• kryoprezervace MeSH
• mitrální chlopeň transplantace   MeSH
• modely u zvířat MeSH
• ovce MeSH
• trikuspidální chlopeň chirurgie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• antivirové látky MeSH
• onkogenní viry účinky léků   MeSH
• skot MeSH
• suramin MeSH
• teoretické modely MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH

Cíl studie: Využití ovce jako experimentálního modelu, při studiu vlivu těhotenství, porodu a urogynekologických operačních výkonů na orgány pánevního dna. Typ studie: Přehledový článek. Název a sídlo pracoviště: Ústav pro péči o matku a dítě, 3. LF UK, Praha. Metodika: Přehled recentní literatury publikované na téma změny biomechanických vlastností a histologické skladby poševní stěny v průběhu gestace a implantace experimentálních materiálů včetně výuky operačních výkonů na ovčím modelu. Výsledky a závěry: Ovce, ač kvadrupední živočich, má morfologicky srovnatelné pánevní dno a pochvu s člověkem. Stejně jako u žen vykazuje mechanické a biochemické změny v průběhu gestace a postpartálně. Je možné ji využít k testování materiálů pro transvaginální urogynekologickou operativu, kterou lze doplnit o simultánní implantaci do břišní stěny. Vzhledem k velikosti modelu je možné provádět celou řadu biomechanických, biochemických a histologických testů, které mohou obohatit naše znalosti o patologických i fyziologických procesech vyvolaných hormonálními změnami či operacemi. Ovce se jeví vhodným velkým zvířecím modelem pro studium vlivu životních milníků pánevních orgánů a je praktická z hlediska vaginální operativy.

Objective: A short literature review of ewe as an experimental model in research of effects of pregnancy, delivery and urogynecological surgical procedures on the pelvic floor. Design: Literature overview. Setting: Institute for the Care of Mother and Child, Third Faculty of Medicine, Prague. Methods: This is an overview of recent literature on experiments using ewes as a model for biomechanical and morphological changes of the vagina induced by pregnancy, delivery and transvaginal graft implantation. Results and conclusion: The ovine pelvic floor and vagina have comparable morphology to human. It’s biomechanical and biochemical properties get changed during the pregnancy and postpartum similarly to clinical findings. Sheep could be used for testing of urogynaecological implants vaginally and simultaneously implanted in the abdominal wall to provide better understanding of anatomical environment differences. The size of the ovine vagina gives the opportunity to perform comprehensive biomechanical, histological and biochemical testing. Experiments and observation may improve our understanding of pathology and physiology of vaginal wall changes induced by hormones, prolapse or surgery.

• MeSH
• experimenty na zvířatech MeSH
• gynekologické chirurgické výkony MeSH
• ovce domácí * MeSH
• pánevní dno * zranění   MeSH
• porod * MeSH
• prolaps pánevních orgánů chirurgie   terapie   MeSH
• rizikové faktory MeSH
• stresová inkontinence moči chirurgie   terapie   MeSH
• suburetrální pásky využití   MeSH
• těhotenství MeSH
• urologické chirurgické výkony MeSH
• vagina zranění   MeSH
• zvířata MeSH
• Check Tag
• těhotenství MeSH
• zvířata MeSH
• Publikační typ
• přehledy MeSH

The objective of this paper was to adapt gene-flow methodology for the calculation of economic weights (EW) for direct and maternal traits and trait components in sheep and to apply this methodology to the Suffolk breed in the Czech Republic. Computer programs were developed in which annual-lambing sheep production systems with purebreeding or partial terminal crossing were simulated. Using these programs, the EW for 12 production and functional traits were estimated for i) Suffolk sires whose sons were used both in purebreeding and in terminal crossing with the 4 dual-purpose breeds, Romanov, Sumavska, Romney, and Merinolandschaf; and ii) Suffolk sires used only for terminal crossing. For case (i), the EW were at first calculated separately for the purebreeding system and for the crossing systems with the 4 dual-purpose breeds in dam position. Compound EW for the general breeding goal for Suffolk were then estimated as weighted averages from the EW in the 5 subsystems. Standardized EW were calculated by multiplying the marginal EW with the genetic SD of the trait, and relative EW were defined as absolute values of the standardized EW expressed as percentage of the sum of the absolute values of the standardized EW over all traits. The 5 most important trait components for Suffolk sires whose sons were used both in purebreeding and in terminal crossing were (relative EW given in parentheses): the direct components of survival rate until weaning (21.0%), daily BW gain until weaning (14.1%), survival rate at birth (14.0%), the maternal component of survival rate until weaning (10.7%), and litter size at lambing (7.6%). There were only small differences between the relative EW calculated for the whole system with pure- and crossbreeding and the relative EW for the purebred system within the Suffolk breed. Therefore, selection of Suffolk rams using a selection index based on the compound EW is expected to be of high efficiency in all of the simulated breeding systems. Only direct traits were relevant for Suffolk sires used only for terminal crossing; the most important (range of relative EW calculated for the 4 crossing systems given in parentheses) were survival rate until weaning (35.2 to 36.5%), daily BW gain until weaning (24.2 to 26.3%), and survival rate at birth (23.7 to 24.8%).

• MeSH
• biologické modely MeSH
• chov ekonomika   MeSH
• genetická variace MeSH
• hmotnostní přírůstek MeSH
• ovce genetika   MeSH
• rozmnožování genetika   fyziologie   MeSH
• tok genů MeSH
• vlna MeSH
• zemědělství ekonomika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVE: To evaluate the host- and biomechanical response to a fully absorbable poly-4-hydroxybutyrate (P4HB) scaffold in comparison with the response to polypropylene (PP) mesh. DESIGN: In vivo animal experiment. SETTING: KU Leuven Center for Surgical Technologies. POPULATION: Fourteen parous female Mule sheep. METHODS: P4HB scaffolds were surgically implanted in the posterior vaginal wall of sheep. The comparative PP mesh data were obtained from an identical study protocol performed previously. MAIN OUTCOME MEASURES: Gross necropsy, host response and biomechanical evaluation of explants, and the in vivo P4HB scaffold degradation were evaluated at 60- and 180-days post-implantation. Data are reported as mean ± standard deviation (SD) or standard error of the mean (SEM). RESULTS: Gross necropsy revealed no implant-related adverse events using P4HB scaffolds. The tensile stiffness of the P4HB explants increased at 180-days (12.498 ± 2.66 N/mm SEM [p =0.019]) as compared to 60-days (4.585 ± 1.57 N/mm) post-implantation, while P4HB degraded gradually. P4HB scaffolds exhibited excellent tissue integration with dense connective tissue and a moderate initial host response. P4HB scaffolds induced a significantly higher M2/M1 ratio (1.70 ± 0.67 SD, score 0-4), as compared to PP mesh(0.99 ± 0.78 SD, score 0-4) at 180-days. CONCLUSIONS: P4HB scaffold facilitated a gradual load transfer to vaginal tissue over time. The fully absorbable P4HB scaffold, in comparison to PP mesh, has a favorable host response with comparable load-bearing capacity. If these results are also observed at longer follow-up in-vivo, a clinical study using P4HB for vaginal POP surgery may be warranted to demonstrate efficacy. TWEETABLE ABSTRACT: Degradable vaginal P4HB implant might be a solution for treatment of POP.

• MeSH
• biomechanika MeSH
• chirurgické síťky * škodlivé účinky   MeSH
• hydroxybutyráty MeSH
• lidé MeSH
• ovce MeSH
• polypropyleny * MeSH
• vagina chirurgie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

AIMS: Cryopreserved mitral allograft valve (MAV) offers theoretical advantages over conventional mechanical or biological prostheses in tricuspid position, especially in infectious endocarditis patients. MAV processing and tricuspid valve (TV) replacement in a sheep model is described. METHODS AND RESULTS: In 20 adult sheep, MAV were harvested, processed and cryopreserved. One month later, recipient's TV were excised and the MAVs were transplanted into the tricuspid position in 13 sheep, under general anaesthesia, via a right thoracotomy, with an extracorporeal circulation (ECC) and cardioplegic heart arrest. Both MAV papillary muscles were anchored into the right ventricular wall by transmural stitches and the MAV anulus was sewn into the recipient's tricuspid anulus. After weaning from ECC, the anatomy and function of the MAV in the tricuspid position was assessed by epicardial echocardiography. The average duration of the ECC was 58 minutes (42-88), the cardioplegic heart arrest was 36 minutes (28-45). Weaning from EEC was always uneventful. Right atrial & pulmonary artery pressure measurements and epicardial echocardiography documented good function of all MAVs. CONCLUSION: MAV remained mechanically strong enough for implantation into the tricuspid position. Reproducible technique of MAV transplantation into the tricuspid position with excellent early postoperative haemodynamic performance was developed.

OBJECTIVE: We aimed to characterize the effect of vaginal or abdominal mesh insertion and of different collagen augmentation of polypropylene mesh in a sheep model. Outcome measures were passive and active biomechanical properties and semiquantitative morphometry. STUDY DESIGN: Forty-two Texel sheep were used: 6 were nonimplanted controls (n = 6), the rest were implanted with polypropylene mesh (n = 12; Avaulta Solo; Bard Medical, Covington, GA) or collagen-coated meshes: Avaulta Plus (n = 12; Bard Medical) and Ugytex (n = 12; Sofradim International, Trevoux, France). Through a single incision, the rectovaginal septum was dissected and a 35 × 35-mm mesh was sutured to the underlying tissues. Abdominally, a 50 × 50-mm mesh was laid over a primarily sutured full thickness 40-mm longitudinal incisional defect. Animals were explanted after 60 or 180 days (n = 6 per group). Outcome measures were passive biomechanics by biaxial tensiometry, active contractility of vaginal explants, and histologic evidence. RESULTS: Vaginal explants were 2.4 times stiffer compared with native vaginal tissue (P < .001), but without differences in comfort zone stiffness or slope of the load-elongation in the physiologic range between the products that were tested. Collagen coating was associated with a 16-fold reduction in contractile force at 180 days, compared with native vaginal tissue, both for Avaulta Plus (P = .032) and Ugytex (P = .015). Abdominal explants were 1.3-times stiffer compared with native abdominal wall tissue (P < .001) and were 1.9-times stiffer compared with vaginal explants. CONCLUSION: Vaginal mesh implantation yields less stiff explants compared with abdominal explants. Vaginal mesh implantation also alters the passive and active biomechanical properties compared with native vaginal tissues. Collagen matrices did not reduce the number of graft-related complications.

• MeSH
• biomechanika MeSH
• břišní stěna patologie   chirurgie   MeSH
• chirurgické síťky * MeSH
• kolagen * MeSH
• ovce MeSH
• polypropyleny * MeSH
• pooperační komplikace etiologie   MeSH
• vagina patologie   chirurgie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Our research was focused on finding the optimal technique of cryopreserved mitral allograft implantation into the tricuspid valve position in a sheep experiment. We prepared 20 cryopreserved mitral valve allografts preoperatively. These were implanted into the tricuspid position in 20 sheep via right thoracotomy, using extracorporeal circulation with cardioplegic heart arrest. We consider the transventricular papillary muscle fixation to be the best technique for obtaining optimal allograft geometry and long-term durability. We evaluated the valve function by epicardial echo before and after implantation, respectively. The findings were confirmed by haemodynamic measurements as well. It was proved that mitral allografts, harvested, processed, and stored according to the Cardiovascular Tissue Bank Protocol remained mechanically strong enough for implantation into the tricuspid position. It was demonstrated that the mitral allograft transplantation into the tricuspid position is feasible. The immediate postoperative haemodynamic performance was excellent in all animals. The mid-term results are currently being evaluated - prior to the possible application of the technique in humans at our institutions.

• MeSH
• alografty MeSH
• echokardiografie MeSH
• kryoprezervace MeSH
• mitrální chlopeň transplantace   MeSH
• ovce MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH