[Use of the Peptigel with Nanofibres in the Bone Defects Healing]. / Vyuzití peptigelu s nanovlákny k lécbe defektu kostní tkáne.

INTRODUCTION Traumatic bone injuries or pathological processes may sometimes result in very extensive bone defects. Currently, the standard procedure applied in clinical humane as well as veterinary medicine to fill a bone defect is the autogenous bone graft which, however, necessitates a more invasive procedure for the patient and in the cases of extensive defects it fails to provide adequate amount of graft. Synthetic bone replacements can be used with no further burden for the patient and can simultaneously be used as the carriers for bioactive molecules or therapeutic drugs. For clinical use, an easy and simple application is one of the requirements that have to be taken into consideration. These requirements are best satisfied by preparations in the form of gel, which may be injected into the defects of various shapes even through minimal surgical approach. MATERIAL AND METHODS Synthetic transparent PGD-AlphaProA hydro-peptide-gel was used as a basis to develop a composite hydrogel scaffold. This gel was enriched by cryogenically ground poly- -caprolactone nanofibers (PCL) in a ratio of 1 ml of gel to 16 µg of nanofibres. In experimental animals (laboratory rat Wistar, n=20), a single regular circular defect of 1.5 mm in diameter was drilled by a low speed drill machine across the whole width of distal femur diaphysis, identically in both the hind legs. In the right hindleg, this defect was filled by injection of 0.05 ml of the composite peptide gel with nanofibers (experimental defect). In the contralateral limb a similar defect was left untreated, without filling (control defect), for spontaneous healing. The group of experimental animals was subsequently divided into four sub-groups (A, B, C, D) for the purpose of further follow-up. One week after the surgical implantation, in the first group of experimental animals (Group A; n = 5) lege artis euthanasia was performed, a radiological examination of both the hind legs was carried out and a sample of the bone from both the control and experimental defect was collected for histologic examination. The other groups of experimental animals were evaluated similarly at 2, 4 and 6 weeks after the surgical procedure (Group B, C, D; n = 5). These groups of experimental animals were assessed using various histological techniques by two independent pathologists. RESULTS A difference between the control and the experimental bone defect was observed only at the healing stage at two weeks after the implantation, when a tendency for greater formation of new bone trabeculas was seen in the defect treated with the composite hydro-peptide-gel with PCL nanofibers. The results show a slightly higher angiogenesis and cellularity at the bone defect site with an increase of newly formed bone tissue and faster colonisation of lamellar bone structures by bone marrow cells at early stages of the healing process (1-2 weeks old defect). In the experimental and control groups, at the later stage of healing (4-6 weeks old defect), the process of healing and bone modelling at the defect site shows no detectable morphological differences. CONCLUSIONS The experimental use of hydro-peptide-gel with PCL nanofibers in vivo in laboratory rats shows very good applicability into the defect site and, compared to the untreated defect within two weeks after the implantation, accelerates the bone healing. This fact could be an advantage especially at the early stage of healing, and thus accelerate the healing of more extensive defects. Key words: peptide gel, polycaprolactone, PCL, replacement, bone, healing, scaffold, nanofibers, biomaterial.

Semi-spherical Radiofrequency Bipolar Device - A New Technique for Liver Resection: Experimental In Vivo Study on the Porcine Model.

The incidence of colorectal carcinoma is still growing in the Czech Republic and also all around the world. With success of oncological treatment is also growing a number of potential patients with liver metastases, who can profit from surgical therapy. The aim of this study was to confirm on porcine models that this method by using new surgical device is effective and safe for patients who have to undergo liver resection. The primary hypothesis of the study was to evaluate whether this new device is able to consistently produce homogeneous and predictable areas of coagulation necrosis without the Pringle maneuver of vascular inflow occlusion. The secondary hypothesis of the study was to compare the standard linear radiofrequency device and a new semi-spherical bipolar device for liver ablation and resection in a hepatic porcine model. Twelve pigs were randomly divided into two groups. Each pig underwent liver resection from both liver lobes in the marginal, thinner part of liver parenchyma. The pigs in first group were operated with standard using device and in the second group we used new developed semi-spherical device. We followed blood count in 0(th), 14(th) and 30(th) day from operation. 14(th) day from resection pigs underwent diagnostic laparoscopy to evaluate of their state, and 30(th) day after operation were all pigs euthanized and subjected to histopathological examination. Histopathological evaluation of thermal changes at the resection margin showed strong thermal alteration in both groups. Statistical analysis of collected dates did not prove any significant (p < 0.05) differences between standard using device and our new surgical tool. We proved safety of new designed semi-spherical surgical. This device can offer the possibility of shortening the ablation time and operating time, which is benefit for patients undergoing the liver resection.

Impact of a high-phosphorus diet on the sonographic and CT appearance of kidneys in degus, and possible concurrence with dental problems.

The main aim of this study was to investigate the impact of pelleted diet of different mineral composition on the sonographic and CT appearance of kidneys in degus (Octodon degus). A total of 35 animals were randomly divided into five groups, fed diets containing different calcium and phosphorus contents (13.5 g/kg calcium and 6.3 g/kg phosphorus, or 9.1 g/kg calcium and 9.5 g/kg phosphorus) and given different amounts of exposure to UV light. Endoscopic examination of the oral cavity as well as renal ultrasonography and CT was performed four times at four-month intervals throughout the study. After 14 months of feeding an experimental diet, all degus were euthanased and subsequently all kidneys were collected for histopathological examination. Animals fed a diet with high dietary phosphate and improper calcium to phosphorus ratio showed severe nephrocalcinosis. Ultrasonographic and CT kidney abnormalities presented as hyperechogenicity and hyperdensity (interpreted as nephrocalcinosis), respectively. The most striking changes were seen at the corticomedullary zone. Ultrasonography and CT correlated in all cases with histopathological findings. Dental disease developed quickly in groups fed diets with an improper calcium and phosphorus content, with obvious apical and coronal elongation of all the teeth. A possible influence of UV light access could not be proved in this study.

Severe granulomatous lesions in several organs from Eustrongylides larvae in a free-ranging dice snake, Natrix tessellata.

During an extensive study regarding the epidemiology of larval Eustrongylides infestation in a free-ranging endangered population of dice snakes (Natrix tessellata) from Histria, Romania, an adult female was euthanized to evaluate pathologic changes. Parasites appeared as nodules at various locations: in subcutaneous connective tissues, on the serosae of the intestines and liver. Histologic sections revealed nematode larvae surrounded by a capsule, forming a parasitic granuloma with 3 layers: macrophage layer, lymphocyte layer, and fibrous capsule. Differences between newly formed and mature granulomas consisted mainly in the eosinophilic infiltration. Other types of parasitic granulomas of reptiles are discussed in comparison with our findings.