Morphological aspects of muscle regeneration in the Nile tilapia (Oreochromis niloticus)

The aim of our study was to analyze the morphological events in the skeletal muscle of the Nile tilapia (Oreochromis niloticus) after a traumatic lesion. Thirty-two fish were used, on which a small longitudinal incision was made in the muscle. The fish were sacrificed after 7, 14, 21, and 42 days and muscle samples were collected from the lesion and processed for morphological analysis. Muscle regeneration in the tilapia occurred gradually through the analyzed period, possibly due to the proliferation and differentiation of myosatellite cells, which were more morphologically evident 7 and 14 days after lesion.

Fator de crescimento derivado de plaquetas humanas obtido por uma metodologia rápida e de baixo custo

Human platelet-derived growth factor (PDGF) was purified from lysates of clinically outdated human platelets by ionic exchange chromatography in CM-Sepharose. The eluated fraction was submitted to the Immunoblot/Slot Blot assay using anti-PDGF-AA and anti-PDGF-BB polyclonal antibodies and was evaluated as to its biological activity through the test of [H 3]-thymidine incorporation in NIH/3T3 cell line fibroblasts in culture. The Immunoblot/Slot Blot assay using anti-PDGF-AA and anti-PDGF-BB antibodies proved the presence of the PDGF in chromatographic cationic fraction. The comparison of biological activities between fiblobrast stimulation assay using recombinant PDGF-AB and partially purified PDGF was demonstrated in 165.796 and 157.567 cpm, respectively. This result, proved the potent mitogenic effect of partially purified PDGF and consequently their evidence about the wound healing activity.

Rigid internal fixation with titanium versus bioresorbable miniplates in the repair of mandibular fractures in rabbits

The purpose of this study was to compare by qualitative histology the efficacy of rigid internal fixation with titanium system and the Lacto Sorb® system in mandibular fractures in rabbits. Thirty male adult rabbits Oryctolagus cuniculus were used. Unilateral mandibular osteotomies were performed between the canine and first premolar. The animals were divided into two groups: for Group I - rigid internal fixation was performed with titanium system 1.5 mm (Synthes, Oberdorf, Switzerland), with two screws of 6 mm (bicortical) on each side of the osteotomy. For Group II-rigid internal fixation was performed with PLLA/PGA system 1.5 mm (Lacto Sorb®, WLorenz, Jacksonville, FL, USA). The histological analysis evaluated the presence of inflammatory reaction, degree of bone healing and degree of resorption of the Lacto Sorb® screws. The results of both fixation systems were similar, only with a small difference after 15 and 30 days. In Group I a faster bony healing was noted. But after 60 days, bony healing was similar in both groups. It is concluded that both PLLA/PGA and titanium plates and screws provide sufficient strength to permit mandibular bone healing. The resorption process of PLLA/PGA osteosynthesis material did not cause acute or chronic inflammatory reaction or foreign body reaction during the studied period. © 2004 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Porous polyethylene for tissue engineering applications in diabetic rats treated with calcitonin: Histomorphometric analysis

Purpose: The purpose of this work was to study the bone tissue reaction after porous polyethylene (Polipore) implantation into surgical defects in the parietal bones of rats with streptozotocin-induced diabetes, treated with salmon calcitonin. Materials and Methods: Porous polyethylene implants were placed in bone defects created in 36 adult female rats. The rats were divided into 3 equal groups: diabetic treated with calcitonin (DCa), diabetic (D), and control (C). The animals of the DCa group received applications of salmon calcitonin on alternating days immediately after the surgery until sacrifice. The rats were sacrificed after 15, 30, 60, and 90 days, and the defects were examined histologically and statistically through histomorphometric analysis. Results: Histomorphometric analysis showed that there was no statistically significant difference in the mean quantity of inflammatory cells among all study groups after 15 and 90 days. At 30 days, a statistically significant difference was observed between the D and C groups and the D and DCa groups. At 60 days, there was no statistically significant difference between the D and DCa groups. Discussion: Porous polyethylene can be considered an option for implant material when there are investigations that prove its biocompatibility and stability in the host tissues. Salmon calcitonin positively aided the bone repair and attenuated the inflammatory response until 30 days after the surgery. Conclusion: Porous polyethylene was tolerated by the host tissues in all groups, and moderate chronic inflammatory reaction was observed up to the 90-day period. Salmon calcitonin attenuated the inflammatory response up until 30 days.

Comparative study of MTA and other materials in retrofilling of pulpless dogs' teeth

This in vivo study compared the effect of mineral trioxide aggregate (MTA), IRM, Super EBA and ZOE in a puttylike consistency, used as retrofilling materials, in the healing process of periapical tissue of pulpless dogs' teeth submitted to a conventional retrofilling technique. Twenty-four premolars obtained from three dogs were used. At the first intervention, the animals were anesthetized, coronal access was obtained and pulpectomy was done. Root canals were kept open to the oral environment for 180 days to induce the formation of apical lesions. After surgical removal of the lesions with curettes, 2 mm of the apical root was cut out perpendicular to the long axis of the teeth, and root-end cavities were shaped with a low-speed round bur. The bone cavities were irrigated and dried, and the root-end cavities were filled with MTA, IRM, Super EBA and ZOE in a puttylike consistency. The bone cavities were passively filled with blood and flaps were sutured. The coronal access openings were cleaned and double-sealed with ZOE and amalgam. After 180 days, the animals were killed by anesthetic overdose, maxilla and mandible were removed and the pieces were processed for histomorphologic analysis. Data were evaluated blindly on the basis of several histopathologic events and the scores obtained were analyzed statistically using the Kruskal Wallis test. No significant differences were observed among MTA, Super EBA and IRM (p>0.05). However, ZOE had a significantly more negative influence on the apical healing (p<0.05). In conclusion, MTA, Super EBA and IRM had similar histopathologic effects among each other and better performance than ZOE used in a puttylike consistency. Furthermore, only MTA stimulated hard tissue deposition in direct contact with the retrofilling material, even when it was inserted under critical conditions.

Histomorphometric evaluation of a threaded, sandblasted, acid-etched implant retrieved from a human lower jaw: A case report

The purpose of this study was to histomorphometrically evaluate the bone-to-implant contact and bone area around a titanium implant retrieved from a human lower jaw. A screw-shaped titanium implant (sandblasted and acid-etched surface) was removed from a 68-year-old male after having been in function for 40 months because of a fracture of the abutment screw. Following the implant removal, an undecalcified section was obtained. The histomorphometric analysis showed a rate of 75.40% of bone-to-implant contact and 89.30% of bone area filling within the limits of the implant threads. The surrounding bone healed in a well-organized pattern and could not be differentiated from the anginal alveolus. The histologic evidence showed a high degree of osseointegration in a threaded, sandblasted, and acid-etched implant retrieved from a human lower jaw after functional loading for 40 months. Copyright © 2005 by Lippincott Williams & Wilkins.

Periodontal plastic surgery associated with treatment for the removal of gingival overgrowth

Background: Excisional biopsies of gingival overgrowths, performed with safety margins, frequently result in mucogingival defects. These defects may produce esthetic problems and increase the chances of dentin hyperesthesia and its possibility of hindering oral hygiene. Methods: Two clinical cases are reported in which gingival overgrowths were removed by excisional biopsy, resulting in unsightly defects. The first clinical case presents an invasive approach for the treatment of a recurrent pyogenic granuloma in the anterior maxilla, and the second depicts a complete removal of a peripheral odontogenic fibroma in the posterior maxilla. In both situations, the soft-tissue defects were repaired by periodontal plastic surgery, including a laterally positioned flap and a coronally positioned flap, respectively. Results: Periodontal plastic surgery successfully restored the defects that resulted from biopsies, and no recurrence has been noticed in the 5-year postoperative follow-up period. Conclusions: The combination of biopsy and periodontal plastic surgery in a one-step procedure seems to be suitable to remove gingival overgrowths in most areas of the mouth, regardless of esthetic significance. Such procedures seem to restore gingival health, encourage healing, and create both esthetics and function in the excised area.

Arthrodesis tarsocrural or tarsometatarsal in 2 dogs using circular external skeletal fixator

An external fixation technique, using a circular fixator, to obtain arthrodesis was evaluated in 2 dogs with infected open lesions and soft tissue damage. In both cases, articular cartilage was curetted, and devitalized bone and necrotic soft tissue were removed. No bone graft was used. The wounds were maintained open and the dogs received postoperative antibiotic therapy. The arthrodesis site was compressed progressively as needed. Infection was eradicated and bony union was obtained in both dogs. It was concluded that the use of a circular fixator is an effective method to achieve arthrodesis.

Restabelecimento funcional do tendão extensor digital longo submetido a ressecção parcial em equinos: Observação macroscópica, histopatológica e ultra-sonográfica

The objective of this work was to study the macroscopic, ultrasonographic and histopathologic aspects from the newly formed cicatricial tissue at the site of the partial resection of the long digital extensor tendon in 10 equines at the moment of functional restoration of the limb with the animal in walk locomotion. The macroscopic exam was performed every 48 hours, the planimetric mensuration every 10 days, the ultrasonographic exam every 15 days and the histopathologyc exam at the end of the study. The wounds showed granulation tissue in retraction, without total lesion epithelization, and the aspects ultrasonographics revealed wound healing with newly formed tissues with variable density and high neovascularization without tendon structural reorganization. The histopathology showed newly formed vascularized tissue, with leukocytic infiltrate and collagenous deposition without full epithelization. The cicatrization tissue formed in the resection region of the tendon, immature and without the structural organization of the normal tendon, showed to be able to functional restoration of the operated limb.

The use of planarians as in vivo animal model to study laser biomodulation effects

A variety of effects is attributed to the photo stimulation of tissues, such as improved healing of ulcers, analgesic and anti-inflammatory effects, stimulation of the proliferation of cells of different origins and stimulation of bone repair. Some investigations that make qualitative evaluations, like wound healing and evaluation of pain and edema, can be conducted in human subjects. However, deeper investigations on the mechanisms of action of the light stimulus and other quantitative works that requires biopsies or destructive analysis has to be carried out in animal models or in cell cultures. In this work, we propose the use of planarians as a model to study laser-tissue interaction. Contrasting with cell cultures and unicellular organisms, planarians are among the simplest organism having tissue layers, central nerve system, digestive and excretory system that might have been platforms for the evolution of the complex and highly organized tissues and organs found in higher organisms. For the present study, 685 nm laser radiation was employed. Planarians were cut transversally, in a plane posterior to the auricles. The body fragments were left to regenerate and the proliferation dynamics of stem cells was studied by using histological analysis. Maximum cell count was obtained for the laser treated group at the 4th experimental day. At that experimental time, we also had the largest difference between the irradiated and the non-irradiated control group. We concluded that the studied flatworm could be an interesting animal model for in vivo studies of laser-tissue interactions.

Estudo morfológico comparativo das cascas e folhas de Stryphnodendron adstringens, S. polyphyllum e S. obovatum - Leguminosae

The genus Stryphnodendron (S.) belongs to the family Leguminosae, subfamily Mimosoideae, which includes mostly trees of tropical and subtropical South America. Extracts of the stem bark are used traditionally by the local population to treat leucorrhoea and diarrhoea, as anti-inflammatory and antiseptic agents (antimicrobial) and to promote blood clotting and wound healing, and in a few cases of gastric ulcers. A review of the literature presented a previous morpho-anatomical study only for S. adstringens (Mart.) Coville. The aim of the present work is to compare morpho-anatomically the stem bark and leaves of three species of Stryphnodendron, known popularly as barbatimão: S. adstringens, S. polyphyllum and S. obovatum, in order to help botanical identification and contribute to quality control. Macro- and microscopical evaluation of the stem barks revealed no significant differences among the species. Morphological analyses of the leaves revealed differences in size, coloration, and pubescence. The leaves of S. adstringens are the largest, glabrous, and concolor. The leaves of S. polyphyllum are smaller, pubescent, and discolor; whereas the leaves of S. obovatum are the same size as those of S. polyphyllum, however, they are glabrous, and discolor.

Homogenous demineralized dentin matrix for application in cranioplasty of rabbits with alloxan-induced diabetes: Histomorphometric analysis

Purpose: The aim of this work was to evaluate the bone-repair process after implantation of homogenous demineralized dentin matrix (HDDM) slices in surgical defects created in the parietal bones of rabbits with alloxan-induced diabetes. Materials and Methods: Forty-eight rabbits were selected and divided into 4 groups of 12 rabbits: the control group, diabetic rabbits (D), diabetic rabbits with a PTFE barrier (D-PTFE), and diabetic rabbits with a PTFE barrier and with slices of homogenous demineralized dentin matrix (D-PTFE+HDDM). The diabetic animals received a single dose of alloxan monohydrate (90 mg/kg) intravenously on the marginal ear vein, and their blood glucose was verified daily. The rabbits were sacrificed after 15, 30, 60, and 90 days. The histologic findings show both better bone structure and significantly greater bone density, as determined by histomorphometric analysis, for the D-PTFE + HDDM group than for the other 3 groups (P < .01). It was also observed that the mean bone density increased gradually from 15 to 90 days (except in the D-PTFE group). Conclusion: It was concluded that the HDDM was biocompatible with the bone repair of diabetic rabbits and that HDDM slices stimulated bone tissue formation. Facilitation of bone repair with HDDM could be useful in diabetic patients.

Effects of fibrin sealer and resorbable gelatin on the repair of osseous defects in rat tibia

Gelfoam® - a biologically resorbable gelatin sponge - has the function of restricting hemorrhage, providing platelet rupture, and supporting fibrin threads. Beriplast® - a fibrinogen-thrombin compound - is used to adhere tissues, to consolidate sutures and in hemostasis. The objective of this study was to perform a histological analysis of the effects of haemostatic agents on osseous repair. These materials were inserted into surgical sites in young rat right and left tibiae. After the observation periods of 7, 14, 30 and 45 days, according to the bioethic protocol, the animals were killed, the tibiae were removed and fixed in 10% formalin and decalcified in equal parts of formic acid and sodium citrate solutions. After routine processing, the specimens were embedded in paraffin for microtomy. Analysis of the results demonstrated that the haemostatic agents are effective in controlling hemorrhage; they stimulate osteogenesis, featuring a pattern of osseous tissue formation similar to the control pattern, although the amount of osseous trabeculae was superior, especially in the Gelfoam group in the periods of 7 and 14 days; 30 days after surgery, the delay in tissue healing in the control group in relation to the experimental groups started to decrease, and the control and experimental groups exhibited similar tissue repair after 45 days, when all the groups exhibited secondary osseous tissue.

Mesh skin graft and digital pad transfer to reconstruct the weight-bearing surface in a dog

A 2-month-old dog was presented with injuries involving both hind paws. Only the 5th digit and its digital pad were present on the right paw. Following a full-thickness skin graft, the 5th digital pad was transferred distal to the metatarsal bones. The transferred pad permitted weight-bearing on the limb.

Bone regeneration in cranioplasty and clinical complications in rabbits with alloxan-induced diabetes

This research evaluated the bone repair process in surgical defects created on the parietal bones of diabetic rabbits using the guided bone regeneration technique to observe the effects of alloxan in the induction of diabetes mellitus. Twenty-four adult rabbits were divided into three study groups: control (C), diabetic (D) and diabetic associated to polytetrafluoroethylene (PTFE) membrane (D-PTFE). For diabetes induction the animals received one dose of monohydrated alloxan (90 mg/kg) by intravenous administration in the auricular or femoral vein. In group D-PTFE the membrane covered both the floor and the surface of the bone defect. In groups D and C, the bone defect was filled up with blood clot. The specimens were fixed in 10% formol and prepared for histomorphometric analysis. The results showed that the 90 mg/kg dose of monohydrate alloxan was sufficient to promote diabetes mellitus when administered in the auricular vein. Bone regeneration was slower in the diabetic group when compared with the control and diabetic-PTFE groups, but there was no significant statistical difference between the two experimental groups (D and D-PTFE). The oral and general clinical complications among the diabetics were weight loss, polyuria, polyphagia and severe chronic gingivitis.