The Role of Antimicrobial Neutrophil Extract in Modification of the Inflammatory Response During Osteochondral Autograft and Allograft Transplantation in Rabbits.

Osteochondral autograft or allograft transplantation is one of the surgical options for the management of large cartilage defects; however, the mechanisms of cartilage healing after this procedure, especially the immunological mechanisms, are not fully understood. The present study examined whether a grafting procedure changed the in-vitro responses of neutrophils and monocyte-derived macrophages (MDMs). Additionally, antimicrobial neutrophil extract (ANE) was assessed for its ability to modulate excessive cellular responses during and after implantation. The neutrophil secretory response was tested by measuring enzyme release and free radical generation, while the MDM response was evaluated by assessing morphological and functional changes of the cells after polarization. Osteochondral implantation evoked a transient secretory response by circulating neutrophils, but MDMs were not activated postoperatively. ANE from rabbit blood may be considered as a modulator of the inflammatory response because of its influence on neutrophils and MDMs. Inhibition of the neutrophil secretory response prevents complications that may arise following excessive activity of these cells. Stimulation of MDMs with ANE induces formation of a partial anti-inflammatory phenotype with enhanced regenerative properties.

In vivo study on scaffolds based on chitosan, collagen, and hyaluronic acid with hydroxyapatite.

Scaffolds based on chitosan, collagen, and hyaluronic acid supplemented with nano-hydroxyapatite were obtained with the use of the freeze-drying method. Composites swelling behavior was assessed by the liquid uptake test. The adhesion and proliferation of human osteosarcoma SaOS-2 cells on the scaffolds were examined in 4-day culture. The biocompatibility of the chosen scaffolds was further studied by in vivo implantation into subcutaneous tissue of rabbits. The results showed low stability of the scaffolds based on chitosan, collagen, and hyaluronic acid supplemented with hydroxyapatite. The addition of hydroxyapatite delayed the degradation process of the obtained scaffolds. The X-ray images of the tissues surrounding the scaffolds showed that both, the control scaffold without hydroxyapatite (HAp) and those with addition of 50% wt. HAp underwent degradation after 6 months. However, the scaffolds supplemented with 80% wt. HAp premained in the implanted place. The results showed satisfactory tissue response on the implanted scaffolds.

Haptoglobin as a treatment monitoring factor in feline plasmacytic gingivostomatitis.

INTRODUCTION: feline plasmacytic gingivostomatitis is an important and fairly common chronic disease. Its complex aetiology - which involves infectious agents, immunological disorders, and even genetic factors adds to the considerable difficulty of its treatment. MATERIALS AND METHODS: the study was performed on 33 cats, 26 animals diagnosed with plasmacytic gingivostomatitis (study group) and 7 clinically healthy cats (control group). The study extended over four examination periods during which clinical and X-ray examinations, morphological and biochemical blood tests, as well as haptoglobin essays were performed. RESULTS: the biochemical and haematological parameters were within normal limits. Blood serum haptoglobin measured on the first day of the treatment was above physiological levels, however its serum concentration decreased as the treatment progressed. CONCLUSIONS: in the present study, despite the bacterial inflammatory condition of periodontal pockets, after the treatment was concluded and symptoms alleviated, neither clinical examinations nor haptoglobin essays revealed deviations from values commonly accepted as normal. Fluctuations in blood serum haptoglobin levels proved to be a useful prognostic in determining the duration of necessary treatment.

Extrathoracic negative pressure ameliorates lung injury during mechanical ventilation in experimental pigs.

Mechanical ventilation (MV) is a supportive and life-saving therapy, however, it can cause ventilator-induced lung injury as a common complication. Thus, recruitment manoeuvres (RM) are applied to open the collapsed alveoli to ensure sufficient alveolar surface area for gas exchange. In the light of the fact that positive pressure ventilation is currently the standard treat- ment for improving pulmonary function, extrathoracic negative pressure is considered as an alter- native form of respiratory support. The aim of this study was to estimate the proinflammatory and oxidative response during MV and lung injury as well as the response after RM. All studied parameters were assessed at the following time points: T1-spontaneous breathing, T2- MV, T3- lung injury, T4 -RM. During MV (T2) elastase, MPO, ALP release, nitrite and superoxide generation significantly increased, whereas in later measurements a decrease in these values was noted. The MDA plasma concentration significantly (p⟨0.05) increased at T2, reaching a level of 13.30±0.87 nmol/ml; at other time points the values obtained were similar to the baseline value of 9.94±0.94 nmol/ml, whereas a gradual decrease in SOD activity at time T2-T4 points in comparison with the baseline value was found. During the study both neutrophil activity and oxi- dative stress indicate exacerbated response after MV and lung injury by bronchoalveolar lavage; however, extrathoracic negative pressure system as the MR ameliorates damaging changes which could further lead to serious lung injury.

Micro-imaging of implanted scaffolds using combined MRI and micro-CT.

RATIONALE AND OBJECTIVES: Thanks to the advanced studies in biomaterial engineering a panoply of polymers can be used to manufacture porous scaffolds for bone tissue regeneration. Suitability of the scaffold for its purpose is determined by factors like size of the pores, its orientation and shape, as well as biocompatibility of the material. Even though a variety of analysis methods is available for in vitro studies, investigating the process of bone reconstruction on implanted scaffold meets with difficulties. METHODS AND MATERIALS: Polylactide porous sponges imbued in hydroxyapatite were implanted into long bones of white New Zealand rabbits for 3 months. The bones obtained from the animals were subjected to MRI and µCT imaging. The obtained images were subsequently fused together. RESULTS AND CONCLUSIONS: Combined MRI and µCT resulted in high resolution diagnostic images which allow for: implant positioning, inflammation divulgement, rating degree of implant resorption, observation of newly formed trabeculae, texture analysis and other quantitative measurements.