Izabela Polkowska

Effect of a carbonated HAP/β-glucan composite bone substitute on healing of drilled bone voids in the proximal tibial metaphysis of rabbits.

A novel elastic hydroxyapatite-based composite of high surgical handiness has been developed. Its potential application in orthopedics as a filler of bone defects has been studied. The biomaterial was composed of carbonated hydroxyapatite (CHAP) granules and polysaccharide polymer (β-1,3-glucan). Cylinders of 4mm in diameter and 6mm in length were implanted into bone cavities created in the proximal metaphysis of tibiae of 24 New Zealand white rabbits. 18 sham-operated animals were used as controls. After 1, 3 or 6 months, the rabbits were euthanized, the bones were harvested and subjected to analysis. Radiological images and histological sections revealed integration of implants with bone tissue with no signs of graft rejection. Peripheral quantitative computed tomography (pQCT) indicated the stimulating effect of the biomaterial on bone formation and mineralization. Densitometry (DXA) analysis suggested that biomineralization of bones was preceded by bioresorption and gradual disappearance of porous ceramic granules. The findings suggest that the CHAP-glucan composite material enables regeneration of bone tissue and could serve as a bone defect filler.

Application of β-1,3-glucan in production of ceramics-based elastic composite for bone repair

BackgroundUnsatisfactory surgical handiness is a commonly known disadvantage of implantable granular bioceramics. To overcome this problem, β-1,3-glucan, biotechnologically derived polysaccharide, has been proposed as a joining agent to combine granular ceramics into novel compact and elastic composite. Hydroxyapatite/glucan elastic material was processed and evaluated as a potential bone void filler.MethodologyThe procedure of composite formation was based on gelling properties of glucan. Its properties were studied using X-ray microtomography, SEM-EDS, FTIR spectroscopy, compression test and ultrasonic method. Sorption index was determined in phosphate buffered saline; bioactivity in simulated body fluid; sterility in growth broth and human blood plasma; implantation procedure in dog model.ResultsHAp/glucan composite is sterilizable, flexible and self-adapting to defect shape. It exhibits bioactivity, good surgical handiness, high sorption index and profitable mechanical properties, resembling those of spongy bone. Results of pilot clinical experiment on animal (dog) patients of a local clinic of animal surgery suggested good healing properties of the composite and its transformation into new bone tissue within critical-size defect.ConclusionsThe results obtained in this study confirm that flexible HAp/glucan composite has potential as a bone-substituting material. Promising results of pilot clinical experiment suggest that further in vivo experiments should be performed.

Elevated Vascular Endothelial Growth Factor (VEGF) levels in the blood serum of dogs with malignant neoplasms of the oral cavity

Angiogenesis plays an essential role in the development of a neoplastic tumour by conditioning both its growth and the formation of metastases. The induction of blood vessel growth occurs under the influence of proangiogenic factors, among which Vascular Endothelial Growth Factor (VEGF) seems to be the most important. The aim of this research was to study the level of VEGF measured by ELISA in the serum of dogs with neoplasms of the oral cavity. The study material comprised samples of neoplastic tissue from 17 operated dogs and the serum of the examined animals as well as of dogs from the control group. The tissue samples were taken from dogs of different breeds, aged 6-14 years. The tumour type was determined in accordance with the applicable WHO classification. Blood samples taken from sick dogs and from animals of the control group were centrifuged, and immunoenzymatic labelling of VEGF was performed in the obtained serum using ELISA and R&D system reagents (Quantikine Canine VEGF). All stages of VEGF labelling were performed according to the recommendation of the test manufacturer. The median of VEGF in the serum of the dogs with neoplasms of the oral cavity was 40.64 pg/mL. The lowest value of 14.26 pg/mL was observed in the case of fibrosarcoma, and the highest value of 99.19 pg/mL in the case of squamous cell carcinoma. The VEGF median in the control group amounted to 11.14 pg/mL whereas the VEGF value in the groups of animals diagnosed with benign tumours ranged between 2.30 and 19.74 pg/mL. Elevated VEGF in the blood serum, in comparison with the benign tumour group and the control group, was observed in all examined neoplasms of the oral cavity. It was suggested that overexpression of VEGF can have a prognostic value and is useful in the early detection of neoplasms.

Molecular-level evaluation of selected periodontal pathogens from subgingival regions in canines and humans with periodontal disease

Dogs commonly serve as a model for various human conditions, including periodontal diseases. The aim of this study was to identify the anaerobic bacteria that colonize the subgingival areas in dogs and humans by using rapid real-time polymerase chain reaction (RT-PCR)-based tests and to compare the results obtained in each species. Bacterial microflora evaluations, both quantitative and qualitative, were performed by applying ready-made tests on twelve dogs and twelve humans. Five samples were collected from each subjects deepest gingival pockets and joined to form a collective sample. The results of the study revealed interspecies similarities in the prevalences of Porphyromonas (P.) gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum. Red complex bacteria comprised the largest portion of the studied bacterial complexes in all study groups, with P. gingivalis being the most commonly isolated bacterium. The results show similarities in the prevalence of bacterial microflora in dogs and humans. Microbiological analysis of gingival pockets by using rapid real-time PCR-based tests in clinical practice, both veterinary and human, can facilitate the choice of appropriate pharmacological treatment and can provide a basis for subsequent verification of the treatments effectiveness.

Determination of pamidronate in bisphosphonate-enriched bone cement by ion-pair hplc and capillary electrophoresis

Abstract The presence of pamidronate during local use of bisphosphonates (BP)-enriched bone cement was determined. The question was whether pamidronate implanted into the bone cement is eluted. The study was performed on 10 probes of BP-enriched bone cement located in 0.9% NaCl. The probes were incubated for 3 and 6 weeks. Ion-pair HPLC was used for the detection of pamidronate. Then, capillary electrophoresis was applied for quantitative analysis of pamidronate in the 3rd and 6th week after incubation. The presence of pamidronate, eluted from BP-enriched bone cement into 0.9% NaCl solution 3 and 6 weeks after incubation, was demonstrated. These results may explain the changes in the level of cytokine RANKL and bone turnover marker osteoprotegrin in rats’ serum treated with BP-enriched bone cement 3 and 6 weeks after surgery. The possibility of effective local use of BP-enriched bone cement in veterinary medicine was underlined. The results, and the former conducted research, point out that the clinical applications of BP-enriched bone cement in vivo may have some validity in the future.

The presence of pamidronate in bone cement affects serum biochemical markers in the rat

Abstract The main aim of the study was to assess whether the presence of biphosphate pamidronate (PA) in the cement implanted into the tibial bones had any effect on the chosen biochemical markers in rat’s serum characterising homeostasis. Forty adult male Wistar rats were divided into two control groups and two experimental groups. Tibial bone of rats in the experimental groups was implanted with PA-enriched cement, whereas the bone in control-group’s rats was implanted with cement without PA. Serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK) were determined three and six weeks after the surgery. Statistically significant differences in the activities of AST and CK of the rats after implantation with non-enriched cement when compared to rats given PA-enriched cement implantation, were found. Six weeks after treatment, AST levels decreased significantly in rats with PA-enriched cement, whereas rats in the control group (implanted with non-enriched cement) demonstrated a significant increase in AST activity in comparison to the same values determined after three weeks and values of PA-enriched cement rats determined after six weeks. The activities of CK were higher in rats with PA-enriched implants than in the control group three weeks after surgery, but six weeks after the treatment, rats implanted with enriched cement reached lower values than animals implanted with non-enriched cement. The use of PA in the cement had also some positive effect on the homeostasis of the rats after the surgery and a positive influence on the post operative muscle regeneration process.

Orthodontic treatment of dogs on the basis of modern knowledge and own experience

Abstract The aim of the study was to demonstrate the orthodontic treatment of malocclusions in dogs, a condition which can lead to cranio-mandibular and functional disorders of the stomatognathic system. The treatment involved the use of maxillofacialorthopaedic appliances, which type depended on the type of disorder and the degree of malocclusion. The applied treatment induced changes in the alveolar bone. Throughout the process of the treatment a great attention was paid to regular brushing off the orthodontic appliance using antiseptics for prophylactic prevention of inflammation of gingival tissue and the palate caused by food getting stuck in the spaces between the teeth.