Evaluation of healing processes of intraosseous defects with and without guided bone regeneration and platelet rich plasma. An animal study.

BACKGROUND: In most cases, the natural healing of intrabony defects only leads to restoration of tissue continuity without differentiation and function. However, repair is not regarded to be an optimal treatment method, as confirmed in many clinical cases. Thus it is important to choose a surgical procedure which makes it possible to achieve restitution ad integrum of the bone structure. The choice of the GBR technique is crucial, in terms of the clinical conditions and limitations resulting from the use of a particular material. OBJECTIVE: The objective of this study has been the analysis of effectiveness of selected surgical treatment techniques of intrabony defects in rabbits. MATERIALS AND METHODS: Research was conducted on 36 white rabbits. The operation technique was a criterion of division into 3 groups: BG/BOC (Bio-Oss Collagen(®)+Bio-Gide Perio(®)), BOC/PRP (Bio-Oss Collagen(®)+PRP), C (control group). Qualitative and quantitative histopathological evaluation was carried out after 1, 3, 6 and 12 months. RESULTS: The highest value of the bone surface area 31.9% (SD 1.8) was achieved in BOC/BG group three months after the implantation, while the lowest was revealed in C - group - 12.5% (SD 1.32) one month following the procedure. CONCLUSIONS: Upon quantitative histological assessment, the bone tissue presented the most intensive osteogenesis within one month from the application of BOC/PRP, whereas this was observed after the application of BOC/BG in later stages. The application of two regenerative methods influenced the rate, quality and overall treatment of intraosseus defects.

Early histological evaluation of bone defect healing with and without guided bone regeneration techniques: experimental animal studies.

INTRODUCTIONS: To obtain osseous tissue regeneration, treatment methods referred to as guided bone regeneration are used which utilize the mechanical, chemical, and biological properties of materials. MATERIAL/METHODS: Eighteen white rabbits were used. Under general anesthesia, a 5 mm in diameter defect was created transcutaneously in the femur trochanter major. The rabbits were divided into three groups depending on the type of the intraosseous defect (ID) treatment: in group I (C) the control IDs were left to heal spontaneously, in II (BOC+BG) the IDs were filled with Bio-Oss Collagen and Bio Gide Perio membrane, and in III (PRP) the IDs were filled with BOC and platelet-rich plasma (Curasan Centrifuge). The animals were sacrificed 1 and 3 months after the surgical procedure. The histological material was stained with hematoxylin and eosin and using the van Gieson method. RESULTS AND CONCLUSIONS: In the earlier histological examinations (1 and 3 months after the procedures), resorption of the biomaterial and the formation of new bone trabeculas were observed in both groups II and III. At the first observation the extent of biomaterial resorption and the intensity of the osteogenic process were greater in group III, but after 3 months group II had a slight advantage. Fragmented remnants of the biomaterial in both groups were surrounded by newly formed bone and locally by fibrous connective tissue. At both observation times the number of bone trabeculas after implantation in groups II and III was greater than in the control group.

Prolonged exposure to inhaled nitric oxide does not affect haemostasis in piglets.

OBJECTIVE: To examine possible adverse effects on haemostasis from prolonged exposure to inhaled nitric oxide (iNO). DESIGN AND SETTING: Blinded, randomised, experimental animal study in a university animal laboratory. INTERVENTIONS: Anaesthetised and intubated piglets received central venous, arterial, and transabdominal urinary catheters. Twelve piglets were studied with triggered pressure support ventilation breathing with an air-oxygen mixture for 30 h with nitric oxide (NO), 40 parts per million (ppm) (n = 6) or without NO gas (n = 6) added. The tests of platelet function were assessed in a separate 1-h experiment in which 12 additional animals were blindly randomised to receive intravenous acetylsalicylic acid (ASA) (n = 7) or placebo (n = 5). MEASUREMENTS AND RESULTS: All 12 animals were clinically stable during the study period of 30 h. Haemostasis was assessed in terms of bleeding time and platelet function by Adeplat-S, reflecting platelet adhesion. Prothrombin fragment 1 + 2, fibrin D-dimer, tissue plasminogen activator and prothrombin complex were measured to investigate whether inhaled NO (iNO) had any effects on thrombin formation, fibrin formation, fibrinolysis or coagulation. All parameters including bleeding time and Adeplat-S were unaffected by iNO. ASA significantly increased bleeding time, but did not affect Adeplat-S. Nitrate in plasma and NOx (nitrate and nitrite) in urine increased significantly in pigs receiving iNO compared with controls. CONCLUSIONS: Prolonged exposure to iNO at 40[Symbol: see text]ppm did not affect bleeding time or coagulation parameters in healthy piglets. The findings do not support the hypothesis that iNO increases the risk of bleeding in humans.

[Application of elemental microanalysis for estimation of osteoinduction and osteoconduction of hydroxyapatite bone implants]. / Zastosowanie mikroanalizy pierwiastkowej do oceny osteoindukcji i osteokondukcji dokostnych implantów hydroksyapatytowych.

Hydroxyapatite (HAp) ceramics based on calcium phosphates, chemical compounds being natural constructive element of bones is now regarded to be one of better implantation materials in osseous surgery and stomatology. HAp is poorly soluble and slowly resorbing in tissues material. Easiness of connecting of hydroxyapatite ceramics with other materials creates possibilities to produce new composites of chemical compounds containing calcium and easier resorbing. An important and till now not fully known problem is influence of hydrodroxyapatite grafts on the processes leading to production of calcium and phosphorus ions responsive for mineralization of bone tissue around the graft. Proliferation of osteoblasts and rate of osseous trabeculas production depends, among others, concentration of calcium and phosphorus ions. The main target of this study was the comparative analysis of the bone mineralisation rate after implantation of hydroxyapatite (HAp) and composites hydroxyapatite + beta tricalcium phosphate (HAp + TCP) and hydroxyapatite + calcium hydrosulfate (HAp + gypsum), on the basis of elemental microanalysis. Implantation studies were carried out on 24 rabbits. Sections were carried out 5, 9, 11 and 14 weeks after implantation of the tested materials. The carried out punctual analysis of the occurring elements and their topographic location (mapping) in bones after implantation showed essential differences among the tested grafts. Those differences were most significant after 5 and 14 weeks and depended on the rate of the tested materials resorption. On the basis of conducted macroscopic evaluation and scanning microscope assessment we can stated that the composite of HAp+TCP showed the best osteocunductive properties, while the best osteoinductive influence was shown by the composite HAp + gypsum.

[The effect of polyester vascular prostheses on synthesis TNF-alpha, IFN-gamma and NO by human peripheral blood leukocytes--in vitro]. / Wplyw poliestrowych protez naczyniowych na synteze TNF-alpha, IFN-gamma oraz NO przez ludzkie leukocyty krwi obwodowej--in vitro.

Vascular prostheses produced on the basis of polyester are today commonly used in vascular surgery. To improve their biofuncionality special technologies are used, among them double knit and hydrophile feature enrichment. These modifications could cause the local activation of leukocytes to produce the mediators of inflammatory reaction, which in turn leads to hyperplasia of endothelium and other dangerous complications. In our study we used two kinds of polyester prostheses: double velour knitted hydrophilic Dallon H and standard double velour knitted prosthesis Dallon as control. The aim of this work was to compare in vitro the levels of cytokines TNF-alpha, interferon (IFN) and nitric oxide (NO) found in the supernatants of human blood leukocyte cultures after stimulation by both these above-mentioned vascular prostheses materials which are designed for use in direct blood contact. Tested implant materials Dallon H had no influence on synthesis of production of IFN, TNF-alpha and NO by human blood leukocytes. These results allow to made the initial selection of biomaterials before their in vivo evaluation.

[Effect of corundum-vancomycin composite on soft tissue reaction]. / Wplyw kompozytu korundowego z Wankomycyna na odczyn tkanek miekkich.

The ceramics on the basis of corundum is used for implantation in the form of porous and solid materials. The solid form was used to produce tissue endoprosthesis while porous form is mainly used to fill in the bone defects. The corundum ceramics are also known to be used as coatings for implants in orthopedics and dentistry. On the other hand there is still a need to find out the new way of treatment of the chronic bone infection, during which the traditional way of antibiotics therapy is no more effective. One of the possibly solution is to use the different biomaterials as drug carriers and in the bone surgery one of the best are porous corundum implants, being themselves of high biocompatibility, and additionally containing Vancomycin. The main target of the investigation presented in this paper was the comparative assessment of the corundum ceramics and its composite containing Vancomycin after implantation into back muscle of the total of 15 rats. During the post mortem macroscopic assessment in the tissues which surrounded the implants there were no any inflammatory neither pathological changes observed. In the microscopic findings, in early periods, the observed inflammatory tissue reaction for implants with vancomycin was significantly greater what could be explained by the high concentration of the antibiotic in the given material. On the basis of the results of macroscopic and microscopic findings we can state that the composite material of corundum ceramic containing vancomycin is of high compatibility and could be regarded as the good drug carrier.

[The bone reaction to the implantation of the corundum-vancomycin composite]. / Reakcja tkanki kostnej po implantacji ceramiki korundowej z Wankomycyna.

Polymethacrylate methylene (PMMA) used as the carrier for antibiotic gentamycin (Septopal) shows today very limited effectiveness. Only 24% of the staphylococcus strains is still susceptible for it. In 1982 this factor was as high as 97%! Because of the growing resistance of different strains of staphylococcus, enterococcus and G(-) bacillus for antibiotics in present use, came into being the necessity for evaluation of the state-of-the-art antibiotic carrier of the new generation, which should be effective to destroy the resistant strains of bacteria. The porous corundum ceramics proved to be good material for this purpose, specially in use for bone surgery. During the laboratory tests it was confirmed that corundum ceramics could be soaked with the different antibiotics of the new generations. The bacteriological tests proved that corundum ceramics soaked with the Vancomycin show the highest possibly antibacterial activity. On the basis of those results we undertook the implantation test on animals. The implantation was carried out on 10 rabbits in which the samples of tested ceramic with Vancomycin were implanted into femoral bone. The investigation periods were set up for 1, 3, 6 and 9 months. On the basis of received results of macroscopic, microscopic and radiological findings we can stated that corundum ceramic with Vancomycin can be used in the treatment of bone infections.

[Investigation of local reaction of muscular tissue after injection of polyvinylpyrrolidone preparation]. / Badania miejscowej reakcji tkanki miesniowej po iniekcji preparatu poliwinylopirolidonu.

Natural preparations for replenishing of hyaluronic acid of zoogenous origin used till now, are characterized with quit low biocompatibility and also too short effect of their action. Recently worked out synthetic polyvinylpyrrolidone preparation PVP, contains modification constituting internally netting of microgels to improve polymer bioresistance. The introduce modification can, however influence PVP biocompatibility after deposition into tissues of the living organism. The aim of research was evaluation of the local reaction of muscular tissue after PVP infection. The results of research concerned a control group where normal saline was used for infections. The research was carried out on 18 Wistar rats and included macroscopic and histologic observations made in the 3rd, 5th, 7th, 14th and 30th day after PVP injection into thigh muscle. The local reaction of muscular tissue was macroscopically characterized with inflammatory reaction till the 7th day after PVP injection, in later terms the observed changes disappeared. Microscopic research showed that PVP till the 7th day after PVP injection caused rather strong diffuse non-specific inflammatory process, yet without essential participation of neutrophils leading to producing of loose intra-muscular. Connective tissue in a later term. The carried out tests showed presence of PVP in muscular tissue till the 30th day after injection.

[Tissue reaction after injection of polyvinylpyrrolidone (PVP) preparation into knee joint. Experiment]. / Odczyn tkankowy po iniekcji preparatu poliwinylopirolidonu (PVP) do stawu kolanowego. Badania doswiadczalne.

Internally netted miscogelatinated preparation on the basis of polyvinylpyrrolidone PVP desioned for viscosuplementation of joint fluid was worked out. Netted structure of microgel grains presents larger resistance to the degrading action of free radicals than analogical linear polymer chains. Application of zoogeous preparations of hyaluronic acid results in short-term effects of their usage in evoking reaction foreign protein. Replenishment of joint fluid with preparation with higher biostability from biocompatible synthetic polymer-polyvinylpyrrolidone could improve the function of synovial through restoration of its proper viscosity and protection of the joint for a longer period of time. The aim of the experiment was determination of bioresistance and reaction of microgel PVP on the tissues of synovial joint. The tests were carried out on 10 white New Zealand rabbits after injection PVP into the knee joint for 3, 7, 14 and 30 days and submitted to macroscopic and histological evaluation. The results of tests were compared with the data obtained after injection of normal saline. Macroscopically, there were no changes in the limits of articular capsule and cartilage; there was only slight and enlargement of synovial membrane in the first 7 days after PVP injection. In histological tests it was observed that reaction in the knee joint after PVP injection was characterised it single inflammatory chains without essential participation of neutrophils observed only in synovial membrane and limited to places were tested preparation was seen. Microgel PVP was present in diverticula of synovial membrane to 30th day after injection.

[Investigation of biocompatibility of the apatite cement]. / Badanie biozgodnosci cementu apatytowego.

The results of experimental studies of biocompatibility of the apatite cement, implanted in the muscular tissue of rats and bone tissue of rabbits were presented in this study. Investigations of the local reactions of the muscular tissue were carried out on 18 rats of Wistar type by implanting samples from the apatite cement in the dorsal muscles. Macroscopic and microscopic investigations were carried out 7, 14, 30, 180, 270 days after the implantation. Investigations of local reactions of bone tissue were carried out on 12 rabbits of New Zealand breed. By implanting the tested material into the femoral bone in the region of trochanter. Sections of the animals were made 1, 3, 6, and 9 months after the surgery. In the early period active inflammatory process was seen in the muscles in the direct vicinity of the implant and then it disappeared leading to formation of a thin fibrous connective tissue capsule. Histological investigations made of bone tissue later showed, formation of young tissue with small focuses of fibrous connective tissue. In the carried out investigations it was shown that the apatite cement is characterized with a high degree of biocompatibility and osteoinductive activity.

Tissue reaction following the implantation of a DALLON H vascular prosthesis in the thoracic aorta defect. Experimental tests.

Vascular prostheses made of polyester or polytetrafluoroethylene fibres are most frequently used nowadays. Woven polyester prostheses are sealed following the suturing in the circulatory system, but they cause a tissue reaction. Knitted polyesters grafts cause a lesser tissue reaction, but demand intraoperative sealing. Thus numerous tests to improve them are conducted. TRICOMED S.A. (Poland) has modified the company's own double velour knitted vascular prosthesis. The graft's physical and chemical features have been changed and hydrophilia has been used, due to which dripping the graft takes little blood and its tightness is achieved in a dozen or so seconds. The evaluation of surgical qualities as well as the healing-in process of the modified knitted hydrophilic prosthesis DALLON H has been conducted at the Department of Experimental Surgery and Biomaterials of Wroclaw Medical University. DALLON H prosthesis was compared to DALLON, a standard double velour knitted prosthesis. The tests were performed on 16 Polish breed piglets with 25-35 kg of weight and 2.5 months of age. Two follow-up periods of 3 and 6 months were established following the surgeries. In each group six piglets had a 6-cm-long segment of DALLON H prosthesis sutured in the thoracic aorta defect, whereas two piglets received a 6-cm-long segment of DALLON prosthesis. The evaluation of surgical qualities of both kinds of grafts was performed intraoperatively. The main emphasis was put on the conditions in which the grafts became tight and the way they were handled during the aortal anastomosis. After 3 and 6 months the animals were autopsied. A macroscopic analysis of the incurred preparations was performed. Roent-genograms of the thoracic aorta sections replaced by the grafts were made in order to establish the shape of their lumen and present calcium salt deposits in their region. Light microscopic tests were performed by dying the preparations with hematoxiline and eosine to differentiate tissues and basic morphotic elements; using the van Giesen method, in order to reveal collagenous fibres; using the Weigert method to reveal elastic fibres, and using the Koess method to reveal calcium salt deposits. An ultrastructural evaluation of the internal surface of the grafted vascular sections was performed by a scanning electron microscope. In view of the experimental tests performed it has been established that DALLON H prosthesis used in vascular surgical procedures is not difficult and the prosthesis can be handled in the same way as some other knitted vascular prostheses. DALLON H does not need preclotting and when the blood flow has been restored through the grafted section the prosthesis immediately becomes completely tight. In view of the tests performed no differences in the healing-in process between the modified DALLON H and DALLON prostheses were observed.

Intraoperative studies and studies on selected parameters of coagulation and fibrinolysis following implantation of DALLON H prostheses with greater surface wettability.

TRICOMED S.A. (Poland) has modified its own knitted polyester vascular prosthesis by change in its physical and chemical characteristics and using hydrophilia. The work has aimed at evaluation of intraoperative tightness and evaluation of change in the number of selected parameters of coagulation and fibrinolysis following implantation of a hydrophilic vascular graft into the thoracic aorta defect in piglets. In view of the experimental tests performed it has been noticed that use of DALLON H prosthesis is easy and the handling of the graft is the same as that of other knitted vascular grafts. DALLON H prosthesis does not need preclotting and it reaches immediate tightness after the blood flow has been restored. In view of the results of the blood studies after implantation coagulation activation in endogenous and exogenous system (aPTT and PT), and increase in activity of factor XII and VII. Concentration of fibrinogen was at a higher level. Thrombin III activation remained at the same level after a primary increase, but protein C activation was decreased. Plasminogen activation was higher which means that the fibrinolytic system was activated. Changes in the level of evaluated indicators were observed until day 14 after implantation of the prosthesis. On day 21st the values of the selected parameters were equal with the values prior to implantation.