Bone regeneration after demineralized bone matrix and castor oil (Ricinus communis) polyurethane implantation

Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial.

Bacterial cellulose-collagen nanocomposite for bone tissue engineering

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Use of bovine bone graft and bone membrane in defects surgically created in the cranial vault of rabbits. Histologic comparative analysis

Purpose: This study was proposed to analyze histologically the process of repairing bone defects created surgically in the cranial vaults of rabbits. Materials and Methods: Thirty adult male rabbits (Oryctolagus cunilicus) received, under general anesthesia, bilateral parietal osteotomies by means of a 6mm-diameter trephine. The bony defects were divided into 4 groups. In group 1 the defect did not receive any treatment; in group 2 the defect was filled with lyophilized bovine bone (Biograft); in group 3 it was filled with bovine bone and covered with a bone matrix membrane (Bioplate); in group 4 it was covered with a bone matrix membrane. Animals were sacrificed in 3 equal groups at 15, 30, and 60 days. The specimens were subjected to routine laboratory procedures to evaluate the degree of bone repair. Results: After 60 days, new bone formation in group 2 was not satisfactory when compared to that of group 3. Large amounts of new bone formation in maturation were seen in group 3. In the defects covered with a membrane the results were similar to those of group 1 (ie, the cavity was filled with fibrous connective tissue). The implanted bone and membranes were totally resorbed. Discussion and Conclusions: the use of a membrane served as a barrier against the migration of cells from the adjacent tissue and the bone graft/membrane preserved the cavity space, resulting in an enhanced osteogenic effect.

Caracterização estrutural do fator de crescimento de fibroblasto-10 (FGF-10) e seu papel na fisiologia folicular ovariana

Background: Interest in folliculogenesis has grown extensively in recent years. Nevertheless, several aspects of follicular activity are still poorly understood. Thus, in vitro culture of ovarian follicles using new substances has been established as a very viable model, enhancing the prospects for a better understanding of follicular activity. Among the family members of the fibroblast growth factor (FGFs), FGF-10 has received recent attention for its ability to regulate the development of ovarian follicles and oocyte maturation. Given the relevance of FGF-10 in the folliculogenesis process, this review aimed to describe the structural features, expression and the main biological effects of FGF-10 on the development of ovarian follicles in mammals.Review: Along this work, it was shown aspects related to structural characterization of FGF-10 and its receptors, as well as FGF-10 expression in different cell types, emphasizing its importance to follicular development. FGF-10 is a paracrine member of the family of FGFs, and is characterized by promoting biological responses via cell surface receptors (FGFRs) of tyrosine kinase-type. of these receptors, FGFR-1, FGFR-2 and FGFR-3 may undergo alternative transcriptional arrangements, enabling the formation of two isoforms (b and c) that have varying degrees of affinity for the various FGFs. Thus, seven FGFR proteins (FGFRs 1b, 1c, 2b, 2c, 3b, 3c and 4) with different binding specificities are generated from the four FGFR genes. The FGFRs transmit intracellular signals after binding with the ligand through the phosphorylation of tyrosine, which activates various transduction patterns in the cytoplasm. The signal transduction of FGF-10 may occur through three main pathways: protein of rat sarcoma (Ras)/MAPK, PLC gamma/Ca(2+) and phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt), which are involved in the transmission of biological signals, leading to cellular proliferation and differentiation. FGF-10 mRNA expression was detected in the ovarian stroma, oocyte and theca cells of preantral and antral follicles. on the other hand, the expression of mRNA for FGF-10 receptors was found in, granulosa cells, theca cells, cumulus cells and oocytes. Although FGFs are widely distributed in different tissues and cell types, the importance and function of FGFs in the ovary are still poorly documented. FGF-10 has been shown to be an important mediator of mesenchymal and epithelial cell interactions during follicle development, promoting follicular survival, activation and growth. Besides the action on folliculogenesis, FGF-10 was recently identified as a growth factor able to improve oocyte competence. However, in antral follicles, the presence of FGF-10 is associated with increased follicular atresia, which matches its anti-estrogenic action.Discussion: From this review, we can conclude that FGF-10 is an important regulator of female reproduction. This growth factor acts in follicle survival, oocyte maturation, expansion of cumulus cells and proliferation of granulosa/theca cellsthrough direct and/or indirect actions in the control of folliculogenesis. Furthermore, FGF-10 seemed to have different effects throughout the follicular development. However, it is necessary to perform additional studies that may provide a better understanding about the importance of FGF-10 during folicullogenesis.

Response of human alveolar bone-derived cells to a novel poly(vinylidene fluoride-trifluoroethylene)/barium titanate membrane

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In vitro evaluation of three different biomaterials as scaffolds for canine mesenchymal stem cells

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Função osteoindutora de fragmentos ósseos conservados em glicerina a 98%: estudo experimental em ratos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosomal imbalances detected in primary bone tumors by comparative genomic hybridization and interphase fluorescence in situ hybridization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In vitro biocompatibility of a novel membrane of the composite poly(vinylidene-trifluoroethylene)/barium titanate

This study was aimed at investigating the in vitro biocompatibility of a novel membrane of the composite poly(vinylidene-trifluoroethylene)/barium titanate (P(VDF-TrFE)/BT). Osteoblastic cells were obtained from human alveolar bone fragments and cultured under standard osteogenic condition until subconfluence. First passaged cells were cultured on P(VDF-TrFE)/BT and expanded polytetrafluoroethylene (e-PTFE - control) membranes in 24-well plates. Cell adhesion and spreading were evaluated at 30 min, and 4 and 24 h. For proliferation assay, cells were cultured for 1, 7, and 10 days. Cell viability was detected by trypan blue at 7 and 10 days. Total protein content and alkaline phosphatase (ALP) activity were measured at 7, 14, and 21 days. Cultures were stained with Alizarin red at 21 days, for detection of mineralized matrix. Data were compared by ANOVA and Student t test. Cell attachment (p = 0.001), cell number (p = 0.001), and ALP activity (p = 0.0001) were greater on P(VDF-TrFE)/BT. Additionally, doubling time was greater on P(VDF-TrFE)/BT (p = 0.03), indicating a decreased proliferation rate. Bone-like nodule formation took place only on P(VDF-TrFE)/BT. The present results showed that both membranes are biocompatible. However, P(VDF-TrFE)/BT presented a better in vitro biocompatibility and allowed bone-like nodule formation. Therefore, P(VDF-TrFE)/BT could be an alternative membrane to be used in guided tissue regeneration. (c) 2006 Wiley Periodicals, Inc.

SUPEROXIDE RADICAL AND TOXICITY OF ENVIRONMENTAL NICKEL EXPOSURE

Three nickel compounds were tested for pancreatic, hepatic and osteogenic damage in rats by a single i.m. injection Ni++ (7 mg kg(-1)). The nickel induced biochemical alterations included significantly increased levels of serum alkaline phosphatase in rats with NiS (75%) and NiO (50%). Amylase and aspartate transaminase were also increased, and lipoperoxide was increased in rats with NiO (5.6-fold) and NiS (3.4-fold). No serum changes were observed with NiCl2. Daily injection of Cu-Zn superoxide dismutase (SOD) conjugated with polyethylene glycol prevented the serum level changes, indicating that superoxide radical is an important intermediate in toxicity of nickel insoluble compounds.

Histomorphometrical analysis of bone formed after maxillary sinus floor augmentation by grafting with a combination of autogenous bone and demineralized freeze-dried bone allograft or hydroxyapatite

Background: Maxillary sinus floor augmentation procedures are currently the treatment of choice when the alveolar crest of the posterior maxilla is insufficient for dental implant anchorage. This procedure aims to obtain enough bone with biomaterial association with the autogenous bone graft to create volume and allow osteo conduction. The objective of this study was to histologically and histometrically evaluate the bone formed after maxillary sinus floor augmentation by grafting with a combination of autogenous bone, from the symphyseal area mixed with DFDBA or hydroxyapatite.Methods: Ten biopsies were taken from 10 patients 10 months after sinus floor augmentation using a combination of 50% autogenous bone plus 50% dernineralized freeze-dried bone allograft (DFDBA group) or 50% autogenous bone plus 50% hydroxyapatite (HA group). Routine histological processing and staining with hernatoxylin and eosin and Masson's trichrome were performed.Results: the histomorphometrical analysis indicated good regenerative results in both groups for the bone tissue mean in the grafted area (50.46 +/- 16.29% for the DFDBA group and 46.79 +/- 8.56% for the HA group). Histological evaluation revealed the presence of mature bone with compact and cancellous areas in both groups. The inflammatory infiltrate was on average nonsignificant and of mononuclear prevalence. Some biopsies showed blocks of the biomaterial in the medullary spaces close to the bone wall, with absence of osteogenic activity.Conclusions: the results indicated that both DFDBA and HA associated with an autogenous bone graft were biocompatible and promoted osteoconduction, acting as a matrix for bone formation. However, both materials were still present after 10 months.

Periosteum-Derived Cells as an Alternative to Bone Marrow Cells for Bone Tissue Engineering Around Dental Implants. A Histomorphometric Study in Beagle Dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An unusual case of malignant cystosarcoma phyllodes of the breast

A unusually large tumor of the left breast diagnosed as a cystosarcoma phyllodes with multiple malignant sarcomatous changes of the stroma, consisting of liposarcoma, myxoid fibrosarcoma, anaplastic, and giant cell sarcoma is described. The weight of 6200 g (13.5 lb) seems to be the largest so far presented in the literature reviewed by the authors. © 1986.

Lesões do trato gastrointestinal na síndrome da imunodeficiência adquirida: estudo de 45 necrópsias consecutivas.

This study was designed to evaluate retrospectively the frequency and etiology of the gastrointestinal (GI) lesions in 45 consecutive necropsies of adult patients with Acquired Immunodeficiency Syndrome (AIDS). Gross descriptions and histological sections of the GI tract, from mouth to anus, were reviewed. The slides were H&E stained, and when necessary special stains and immunohistochemical methods were also employed. There were lesions in GI tract in 37 (82.3%) patients; the mouth was the segment most frequently involved (73.3% of the cases), followed by the colon (55.5%). Multiple lesions occurred in 17 (37.7%) cases. Cytomegalovirus caused colonic lesions in 35.7% of the cases. Candidiasis was observed in 26.6% mainly in the mouth and herpes simplex (8.8%) was the important agent of esophageal lesions. Oral hairy leukoplasia associated with HPV was found in 16 (35.5%) cases. Neoplasia was diagnosed in 7 (15.5%) cases: four Kaposi's sarcoma, two anal intramucosal carcinomas and one gastric lymphoma. Our data confirm the high frequency and variety of GI tract alterations in AIDS.