The spleen is a large and highly vascularized secondary lymphatic organ. Spleen injuries are among the most frequent trauma-related injuries in the abdominal region. The aims of the study were to assess the volume fractions of the main splenic tissue components (red pulp, white pulp, trabeculae and reticular fibres) and to determine the severity of splenic injury due to the experimental impact test. Porcine spleens (n = 17) were compressed by 6.22 kg wooden plate using a drop tower technique from three impact heights (50, 100 and 150 mm corresponding to velocities 0.79, 1.24 and 1.58 m/s). The pressure was measured via catheters placed in the splenic vein. The impact velocity was measured using lasers. The severity of induced injuries was analysed on the macroscopic level. The volume fractions of splenic components were assessed microscopically using stereology. The volume fraction of the red pulp was 76.4%, white pulp 21.3% and trabeculae 2.7% respectively. All impact tests, even with the low impact velocities, led to injuries that occurred mostly in the dorsal extremity of the spleen, and were accompanied by bleeding, capsule rupture and parenchyma crushing. Higher impact height (impact velocity and impact energy) caused more severe injury. Porcine spleen had the same volume fraction of tissue components as human spleen, therefore we concluded that the porcine spleen was a suitable organ model for mechanical experiments. Based on our observations, regions around hilum and the diaphragmatic surface of the dorsal extremity, that contained fissures and notches, were the most prone to injury and required considerable attention during splenic examination after injury. The primary mechanical data are now available for the researchers focused on the splenic trauma modelling.
- MeSH
- Humans MeSH
- Swine Diseases * MeSH
- Swine MeSH
- Spleen MeSH
- Wounds, Nonpenetrating * veterinary MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Performance in strike combat sports is mostly evaluated through the values of the net force, acceleration, or speed to improve efficient training procedures and/or to assess the injury. There are limited data on the upper limb striking area, which can be a useful variable for contact pressure assessment. Therefore, the aim of this study was to determine the contact area of the upper limb in three different strike technique positions. A total of 38 men and 38 women (n = 76, 27.3 ± 8.5 years of age, 73.9 ± 13.8 kg of body weight, 173.3 ± 8.4 cm of body height) performed a static simulation of punch with a fist, palm strike, and elbow strike, where three segments of the right upper limb were scanned. The analysis of 684 images showed a correlation (r = 0.634) between weight and punch technique position in men and significant differences in elbow strike (p < 0.001) and palm strike (p < 0.0001) between women and men. In both groups, the palm demonstrated the largest area and the elbow the smallest one. These data may be used to evaluate strike contact pressure in future studies in forensic biomechanics and assessment of injury in combat sports and self-defense.
- Publication type
- Journal Article MeSH
Despite the wide choice of commercial heart valve prostheses, cryopreserved semilunar allograft heart valves (C-AHV) are required, and successfully transplanted in selected groups of patients. The expiration limit (EL) criteria have not been defined yet. Most Tissue Establishments (TE) use the EL of 5 years. From physiological, functional, and surgical point of view, the morphology and mechanical properties of aortic and pulmonary roots represent basic features limiting the EL of C-AHV. The aim of this work was to review methods of AHV tissue structural analysis and mechanical testing from the perspective of suitability for EL validation studies. Microscopic structure analysis of great arterial wall and semilunar leaflets tissue should clearly demonstrate cells as well as the extracellular matrix components by highly reproducible and specific histological staining procedures. Quantitative morphometry using stereological grids has proved to be effective, as the exact statistics was feasible. From mechanical testing methods, tensile test was the most suitable. Young's moduli of elasticity, ultimate stress and strain were shown to represent most important AHV tissue mechanical characteristics, suitable for exact statistical analysis. C-AHV are prepared by many different protocols, so as each TE has to work out own EL for C-AHV.
- MeSH
- Allografts MeSH
- Aorta MeSH
- Aortic Valve * surgery MeSH
- Cryopreservation * MeSH
- Humans MeSH
- Elastic Modulus MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Anastomotic leakage is a dreadful complication in colorectal surgery. It has a negative impact on postoperative mortality, long term life quality and oncological results. Nanofibrous polycaprolactone materials have shown pro-healing properties in various applications before. Our team developed several versions of these for healing support of colorectal anastomoses with promising results in previous years. In this study, we developed highly porous biocompatible polycaprolactone nanofibrous patches. We constructed a defective anastomosis on the large intestine of 16 pigs, covered the anastomoses with the patch in 8 animals (Experimental group) and left the rest uncovered (Control group). After 21 days of observation we evaluated postoperative changes, signs of leakage and other complications. The samples were assessed histologically according to standardized protocols. The material was easy to work with. All animals survived with no major complication. There were no differences in intestinal wall integrity between the groups and there were no signs of anastomotic leakage in any animal. The levels of collagen were significantly higher in the Experimental group, which we consider to be an indirect sign of higher mechanical strength. The material shall be further perfected in the future and possibly combined with active molecules to specifically influence the healing process.
- Publication type
- Journal Article MeSH
INTRODUCTION AND HYPOTHESIS: Objective of this study was to develop an MRI-based finite element model and simulate a childbirth considering the fetal head position in a persistent occiput posterior position. METHODS: The model involves the pelvis, fetal head and soft tissues including the levator ani and obturator muscles simulated by the hyperelastic nonlinear Ogden material model. The uniaxial test was measured using pig samples of the levator to determine the material constants. Vaginal deliveries considering two positions of the fetal head were simulated: persistent occiput posterior position and uncomplicated occiput anterior position. The von Mises stress distribution was analyzed. RESULTS: The material constants of the hyperelastic Ogden model were measured for the samples of pig levator ani. The mean values of Ogden parameters were calculated as: μ1 = 8.2 ± 8.9 GPa; μ2 = 21.6 ± 17.3 GPa; α1 = 0.1803 ± 0.1299; α2 = 15.112 ± 3.1704. The results show the significant increase of the von Mises stress in the levator muscle for the case of a persistent occiput posterior position. For the optimal head position, the maximum stress was found in the anteromedial levator portion at station +8 (mean: 44.53 MPa). For the persistent occiput posterior position, the maximum was detected in the distal posteromedial levator portion at station +6 (mean: 120.28 MPa). CONCLUSIONS: The fetal head position during vaginal delivery significantly affects the stress distribution in the levator muscle. Considering the persistent occiput posterior position, the stress increases evenly 3.6 times compared with the optimal head position.
- MeSH
- Finite Element Analysis MeSH
- Labor Presentation * MeSH
- Pelvic Floor diagnostic imaging MeSH
- Fetus * MeSH
- Swine MeSH
- Pregnancy MeSH
- Delivery, Obstetric MeSH
- Animals MeSH
- Check Tag
- Pregnancy MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: The Memorial Sloan-Kettering Cancer Center (MSKCC) prognostic model has been widely used for the prediction of the outcome of metastatic renal cell carcinoma (mRCC) patients treated with systemic therapies, however, data from large studies are limited. This study aimed at the evaluation of the impact of the MSKCC score on the outcomes in mRCC patients treated with first-line sunitinib, with a focus on the intermediate-risk group. METHODS: Clinical data from 2390 mRCC patients were analysed retrospectively. Progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) were analysed according to the MSKCC risk score. RESULTS: ORR, median PFS, and OS for patients with one risk factor were 26.7%, 10.1, and 28.2 months versus 18.7%, 6.2, and 16.2 months, respectively, for those with two risk factors (ORR: p = 0.001, PFS: p < 0.001, OS: p < 0.001). ORR, median PFS, and OS were 33.0%, 17.0, and 44.7 months versus 24.1%, 9.0, and 24.1 months versus 13.4%, 4.5, and 9.5 months in the favourable-, intermediate-, and poor-risk groups, respectively (ORR: p < 0.001, PFS: p < 0.001, OS: p < 0.001). CONCLUSIONS: The results of the present retrospective study demonstrate the suitability of the MSKCC model in mRCC patients treated with first-line sunitinib and suggest different outcomes between patients with one or two risk factors.
- Publication type
- Journal Article MeSH
The aortic and pulmonary allograft heart valves (AHV) are used in the cardiac surgery for replacing the impaired semilunar valves. They are harvested from donor hearts and cryostored in tissue banks. The expiration period was set to 5 years arbitrarily. We hypothesized that their mechanical and structural properties do not deteriorate after this period. A total of 64 human AHV (31 aortic and 33 pulmonary) of different length of cryopreservation (fresh, 0-5, 5-10, over 10 years) were sampled to different tissue strips (artery, leaflet, ventriculo-arterial junction) and tested by tensile test with loading velocity 10 mm/min until tissue rupture. Neighbouring regions of tissue were processed histologically and evaluated for elastin and collagen area fraction. The results were evaluated statistically. In aortic AHV, the physical deformation response of wall samples to stress did not changed significantly neither during the process of cryopreservation nor during the first 10 years of storage. In pulmonary AHV, the ultimate strain dropped after 5 years of cryopreservation indicating that pulmonary artery was significantly less deformable at the time of rupture. On the other hand, the ultimate stress was equal during the first 10 years of cryostorage. The changes in collagen and elastin amount in the tissue samples were not associated with mechanical impairment. Neither elasticity, stiffness and solidity nor morphology of aortic and pulmonary AHV did not change reasonably with cryopreservation and in the first 10 years of cryostorage. This evidence suggests that the expiration period might be extended in the future.
- MeSH
- Aortic Valve transplantation MeSH
- Adult MeSH
- Elastin analysis MeSH
- Transplantation, Homologous MeSH
- Collagen analysis MeSH
- Cryopreservation methods MeSH
- Middle Aged MeSH
- Humans MeSH
- Pulmonary Valve transplantation MeSH
- Tissue Banks * MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
