Potential of Bioactive Glass Particles of Different Size Ranges to Affect Bone Formation in Interproximal Periodontal Defects in Dogs

Background: The aim of this study was to compare the potential of bioactive glass particles of different size ranges to affect bone formation in periodontal defects, using the guided tissue regeneration model in dogs. Methods: In six dogs, 2-wall intrabony periodontal defects were surgically created and chronified on the mesial surfaces of mandibular third premolars and first molars bilaterally. After 1 month, each defect was randomly assigned to treatment with bioabsorbable membrane in association with bioactive glass with particle sizes between 300 and 355 mu m (group 1) or between 90 and 710 mu m (group 2), membrane alone (group 3), or negative control (group 4). The dogs were sacrificed 12 weeks after surgeries, and histomorphometric measurements were made of the areas of newly formed bone, new mineralized bone, and bioactive glass particle remnants. Results: With regard to the area of bioactive glass particle remnants, there was a statistically significant difference between groups 1 and 2, favoring group 1. There were greater areas of mineralized bone in groups 1 and 2 compared to groups 3 and 4 (P<0.05). Conclusion: The bioactive glass particles of small size range underwent faster resorption and substitution by new bone than the larger particles, and the use of bioactive glass particles favored the formation of mineralized bone. J Periodontol 2009;80:808-815.

Periapical Tissue Response After Use of Intermediate Restorative Material, Gutta-Percha, Reinforced Zinc Oxide Cement, and Mineral Trioxide Aggregate as Retrograde Root-End Filling Materials: A Histologic Study in Dogs

Purpose: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model. Materials and Methods: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values. Results: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials. Conclusions: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:2041-2047, 2012

Phenotypical characterization and adhesin identification in escherichia coli strains isolated from dogs with urinary tract infections

Pathogenic strains of Escherichia coli are the most common bacteria associated with urinary tract infections in both humans and companion animals. Standard biochemical tests may be useful in demonstrating detailed phenotypical characteristics of these strains. Thirteen strains of E. coli isolated from dogs with UTIs were submitted to biochemical tests, serotyping for O and H antigens and antimicrobial resistance testing. Furthermore, the presence of papC, sfa, and afa genes was evaluated by PCR, and genetic relationships were established using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). The antimicrobial that showed the highest resistance rate among the isolates was nalidixic acid (76.9%), followed by cephalotin (69.2%), sulfamethoxazole + trimethoprim (61.5%), tetracycline (61.5%), streptomycin (53.8%), ciprofloxacin (53.8%), ampicillin (46.2%), gentamicin (30.8%) and chloramphenicol (23.1%). No isolate was resistant either to meropenem or nitrofurantoin. Among the five clusters that were identified using ERIC-PCR, one cluster (A) had only one strain, which belonged to a serotype with zoonotic potential (O6:H31) and showed the genes papC+, sfa+, afa-. Strains with the genes papC-, sfa+, afa- were found in two other clusters (C and D), whereas all strains in clusters B and E possessed papC-, sfa-, afa- genes. Sucrose and raffinose phenotypic tests showed some ability in discriminating clusters A, B and C from clusters D and E.

Effect of soft laser in bone repair after expansion of the midpalatal suture in dogs

Introduction: The purpose of this research was to study the influence of soft laser treatment on the process of bone repair after expansion of the midpalatal suture. Methods: The sample for this case-control experimental study was 11 dogs. They were randomly divided into 2 groups, both of which underwent rapid maxillary expansion with a hyrax appliance. The animals in group 1 were also treated with laser therapy. They were killed, and histologic specimens of the palatal suture were prepared. The Student t test was applied for independent data, and the Mann-Whitney test was used for nonparametric data. Results: A significant difference was observed in the quality of the palatal sutures between the animals in groups 1 and 2. The connective tissues of the sutures in the group 1 animals were similar to the original configurations, with more advanced osteogenesis and fibrogenesis, compared with those of group 2. Conclusions: Soft laser appears to influence the behavior of the repair process, contributing to suture reorganization and palatal bone osteogenesis during and after expansion. (Am J Orthod Dentofacial Orthop 2012; 142: 615-24)

Short implants (6 mm) installed immediately into extraction sockets: An experimental study in dogs

Aim: To evaluate the effect of implant length (6 mm vs. 11 mm) on osseointegration (bone-toimplant contact) of implants installed into sockets immediately after tooth extraction. Material and methods: In six Labrador dogs, the pulp tissue of the mesial roots of P-3(3) was removed and the root canals were filled. Flaps were elevated bilaterally, the premolars hemisectioned and the distal roots removed. Recipient sites were prepared in the distal alveolus and a 6 mm or an 11 mm long implant was installed at the test and control sites, respectively. Non-submerged healing was allowed. After 4 months of healing, block sections of the implant sites were obtained for histological processing and peri-implant tissue assessment. Results: No statistically significant differences were found between test and control sites both for hard and soft tissue parameters. The bone-to-implant contact evaluated at the apical region of the implants was similar as well. Although not statistically significant, the location of the top of the bony crest at the buccal aspect was more apical in relation to the implant shoulder at the test compared with the control sites (2.0 +/- 1.4 and 1.2 +/- 1.1 mm, respectively). Conclusions: Shorter implants (6 mm) present with equal osseointegration than do longer implants (11 mm).

Infection in domestic dogs (Canis lupus familiaris, Linnaeus, 1758) from Guaratuba, Parana, Brazil by circulating microfilariae of Acanthocheilonema reconditum (Grassi, 1889)

The epidemiologic frameworks of zoonosis periodically change in some of its aspects, involving the emergence or reemergence of men and animals' worsening of health. In this scenario, in which rapid changes can happen, the analysis of the prevalence of diseases, as the filariasis diagnosed in dogs from the coastline of Parana, has significant relevance. This study has been carried out with 422 dogs and aimed to determine the prevalence of circulating microfilariae of Acanthocheilonema reconditum, both in animals accommodated at the municipal kennels, as those that live in the district COHAPAR II, both places located in the metropolitan area of the city of Guaratuba-Parana, through two blood tests: evaluation of fresh blood, by the technique of the 'thick drop' and method of Knott modified by Newton and Wright. Thirty of the evaluated animals (7.10%), twenty two males and eight females, showed the presence of microfilariae of A. reconditum as result.

Occurrence and antimicrobial susceptibility of Porphyromonas spp. and Fusobacterium spp. in dogs with and without periodontitis

The occurrence of Porphyromonas gulae, Porphyromonas macacae, Fusobacterium nucleatum and Fusobacterium canifelinum in subgingival plaque from dogs with and without periodontitis as well as their antimicrobial susceptibility were evaluated. From 50 dogs with periodontitis were identified 38 P. gulae, 8 P. macacae, 26 F. nucleatum and 15 F. canifelinum, and from 50 dogs without periodontitis were identified 15 P. gulae, 12 F. nucleatum and 11 F. canifelinum. All strains were susceptible to most of the antibiotics tested, however, different resistance rates to clarithromycin, erythromycin and metronidazole among strains were observed. The role of P. gulae, P. macacae, F. nucleatum and F. canifelinum in periodontal disease of household pets needs to be defined to a better prevention and treatment of the canine periodontitis. (c) 2012 Elsevier Ltd. All rights reserved.

Buccal Bone Plate Remodeling After Immediate Implant Placement With and Without Synthetic Bone Grafting and Flapless Surgery: Radiographic Study in Dogs

Recent studies in animals have shown pronounced resorption of the buccal bone plate after immediate implantation. The use of flapless surgical procedures prior to the installation of immediate implants, as well as the use of synthetic bone graft in the gaps represent viable alternatives to minimize buccal bone resorption and to favor osseointegration. The aim of this study was to evaluate the healing of the buccal bone plate following immediate implantation using the flapless approach, and to compare this process with sites in which a synthetic bone graft was or was not inserted into the gap between the implant and the buccal bone plate. Lower bicuspids from 8 dogs were bilaterally extracted without the use of flaps, and 4 implants were installed in the alveoli in each side of the mandible and were positioned 2.0 mm from the buccal bone plate (gap). Four groups were devised: 2.0-mm subcrestal implants (3.3 x 8 mm) using bone grafts (SCTG), 2.0-mm subcrestal implants without bone grafts (SCCG), equicrestal implants (3.3 x 10 mm) with bone grafts (EGG), and equicrestal implants without bone grafts (ECCG). One week following the surgical procedures, metallic prostheses were installed, and within 12 weeks the dogs were sacrificed. The blocks containing the individual implants were turned sideways, and radiographic imaging was obtained to analyze the remodeling of the buccal bone plate. In the analysis of the resulting distance between the implant shoulder and the bone crest, statistically significant differences were found in the SCTG when compared to the ECTG (P = .02) and ECCG (P = .03). For mean value comparison of the resulting linear distance between the implant surface and the buccal plate, no statistically significant difference was found among all groups (P > .05). The same result was observed in the parameter for presence or absence of tissue formation between the implant surface and buccal plate. Equicrestally placed implants, in this methodology, presented little or no loss of the buccal bone. The subcrestally positioned implants presented loss of buccal bone, even though synthetic bone graft was used. The buccal bone, however, was always coronal to the implant shoulder.

Effect of Si addition on Ca- and P-impregnated implant surfaces with nanometer-scale roughness: an experimental study in dogs

Objectives: To investigate the effect of Si addition on a nanometer-scale roughness Ca and P implant surfaces in a canine tibia model by biomechanical and histomorphometric evaluations. Material and methods: The implant surfaces comprised a resorbable media CaP microblasted (control) and a CaP resorbable media + silica-boost microblasted (experimental) surfaces. Surfaces were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and optical interferometry (IFM) down to the nanometric level. The animal model involved the bilateral placement of control (n = 24) and experimental surface (n = 24) implants along the proximal tibiae of six dogs, remaining in vivo for 2 or 4 weeks. After euthanization, half of the specimens were torquedto- interface failure, and the other half was subjected to histomorphologic and bone-to-implant contact (BIC) evaluation. Torque and BIC statistical evaluation was performed by the Friedman test at 95% level of significance, and comparisons between groups was performed by the Dunn test. Results: IFM and SEM observations depicted comparable roughness parameters for both implant surfaces on the micrometer and nanometer scales. XPS analysis revealed similar chemical composition, except for the addition of Si on the experimental group. Torque-to-interface failure and BIC mean values showed no significant differences (P = 0.25 and 0.51, respectively) at both 2- and 4-week evaluation points for experimental and control groups. Early bone healing histomorphologic events were similar between groups. Conclusions: The experimental surface resulted in not significantly different biomechanical fixation and BIC relative to control. Both surfaces were biocompatible and osseoconductive.

Early peri-implant endosseous healing of two implant surfaces placed in surgically created circumferential defects. A histomorphometric and fluorescence study in dogs

Objective Several implant surfaces are being developed, some in the nanoscale level. In this study, two different surfaces had their early healing properties compared in context of circumferential defects of various widths. Material and methods Six dogs had the mandibular premolars extracted. After 8weeks, four implants were placed equicrestally in each side. One acted as control, while the others were inserted into sites with circumferential defects of 1.0, 1.5 and 2.0mm wide and 5mm deep. A nano-modified surface was used on one side and a micro-rough on the other. Bone markers were administered on the third day after implant placement and then after 1, 2, 4weeks to investigate the bone formation dynamic through fluorescence analysis. Ground sections were prepared from 8-week healing biopsies and histomorphometry was performed. Results The fluorescence evaluation of the early healing showed numerically better results for the nano-modified group; however this trend was not followed by the histomorphometric evaluation. A non-significant numerical superiority of the micro-rough group was observed in terms of vertical bone apposition, defect bone fill, bone-to-implant contact and bone density. In the intra-group analysis, the wider defects showed the worse results while the control sites showed the best results for the different parameters, but without statistical relevance. Conclusion Both surfaces may lead to complete fill of circumferential defects, but the gap width has to be considered as a challenge. The nano-scale modification was beneficial in the early stages of bone healing, but the micro-rough surface showed numerical better outcomes at the 8-week final period.

Evaluation of a nanometer roughness scale resorbable media-processed surface: a study in dogs

Objectives: This study compared the biomechanical fixation and bone-to-implant contact (BIC) of implants with different surfaces treatment (experimental resorbable blasting media-processed nanometer roughness scale surface, and control dual acid-etched) in a dog model. Material and methods: Surface characterization was made in six implants by means of scanning electron microscopic imaging, atomic force microscopy to evaluate roughness parameters, and X-ray photoelectron spectroscopy (XPS) for chemical assessment. The animal model comprised the bilateral placement of control (n = 24) and experimental surface (n = 24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Half of the specimens were biomechanically tested (torque), and the other half was subjected to histomorphologic/ morphometric evaluation. BIC and resistance to failure measures were each evaluated as a function of time and surface treatment in a mixed model ANOVA. Results: Surface texturing was significantly higher for the experimental compared with the control surface. The survey XPS spectra detected O, C, Al, and Ti at the control group, and Ca (similar to 0.2-0.9%) and P (similar to 1.7-4.1%) besides O, C, Al, and Ti at experimental surfaces. While no statistical difference in BIC was found between experimental and control surfaces or between 2 and 4 weeks in vivo, both longer time and use of experimental surface significantly increased resistance to failure. Conclusions: The experimental surface resulted in enhanced biomechanical fixation but comparable BIC relative to control, suggesting higher bone mechanical properties around the experimental implants.

Human Adipose-Derived Mesenchymal Stromal Cells Injected Systemically Into GRMD Dogs Without Immunosuppression Are Able to Reach the Host Muscle and Express Human Dystrophin

Duchenne muscular dystrophy (DMD), a lethal X-linked disorder, is the most common and severe form of muscular dystrophies, affecting I in 3,500 male births. Mutations in the DMD gene lead to the absence of muscle dystrophin and a progressive degeneration of skeletal muscle. The possibility to treat DMD through cell therapy has been widely investigated. We have previously shown that human adipose-derived stromal cells (hASCs) injected systemically in SJL mice are able to reach and engraft in the host muscle, express human muscle proteins, and ameliorate the functional performance of injected animals without any immunosuppression. However, before starting clinical trials in humans many questions still need to be addressed in preclinical studies, in particular in larger animal models, when available. The best animal model to address these questions is the golden retriever muscular dystrophy (GRMD) dog that reproduces the full spectrum of human DMD. Affected animals carry a mutation that predicts a premature termination codon in exon 8 and a peptide that is 5% the size of normal dystrophin. These dogs present clinical signs within the first weeks and most of them do not survive beyond age two. Here we show the results of local and intravenous injections of hASCs into GRMD dogs, without immunosuppression. We observed that hASCs injected systemically into the dog cephalic vein are able to reach, engraft, and express human dystrophin in the host GRMD dystrophic muscle up to 6 months after transplantation. Most importantly, we demonstrated that injecting a huge quantity of human mesenchymal cells in a large-animal model, without immunosuppression, is a safe procedure, which may have important applications for future therapy in patients with different forms of muscular dystrophies.

In vitro differentiation of mesenchimal stem cells of dogs into osteogenic precursors

Lima S.A.F., Wodewotzky T.I., Lima-Neto J.F., Beltrao-Braga P.C.B. & Alvarenga F.C.L. 2012. [In vitro differentiation of mesenchimal stem cells of dogs into osteogenic precursors.] Diferenciacao in vitro de celulas-tronco mesenquimais da medula ossea de caes em precursores osteogenicos. Pesquisa Veterinaria Brasileira 32(5):463-469. Departamento de Reproducao Animal e Radiologia Veterinaria, Faculdade de Medicina Veterinaria e Zootecnia, Universidade Estadual Paulista, Campus de Botucatu, Distrito de Rubiao Junior s/n, Botucatu, SP 18618-970, Brazil. E-mail: silviavet@usp.br The aim of our research was to evaluate the potential for osteogenic differentiation of mesenchimal stem cells (MSC) obtained from dog bone marrow. The MSC were separated using the Ficoll method and cultured under two different conditions: DMEM low glucose or DMEM/F12, both containing L-glutamine, 20% of FBS and antibiotics. MSC markers were tested, confirming CD44+ and CD34- cells with flow cytometry. For osteogenic differentiation, cells were submitted to four different conditions: Group 1, same conditions used for primary cell culture with DMEM supplemented media; Group 2, same conditions of Group 1 plus differentiation inductors Dexametazone, ascorbic acid and beta-glicerolphosphate. Group 3, Cells cultured with supplemented DMEM/F12 media, and Group 4, same conditions as in Group 3 plus differentiation inductors Dexametazone, ascorbic acid and beta-glicerolphosphate. The cellular differentiation was confirmed using alizarin red and imunostaining with SP7/Osterix antibody. We observed by alizarin staining that calcium deposit was more evident in cells cultivated in DMEM/F12. Furthermore, by SP/7Osterix antibody immunostaining we obtained 1:6 positive cells when using DMEM/F12 compared with 1:12 for low-glucose DMEM. Based on our results, we conclude that the medium DMEM/F12 is more efficient for induction of differentiation of mesenchymal stem cells in canine osteogenic progenitors. This effect is probably due to the greater amount of glucose in the medium and the presence of various amino acids.

Germline mutation analysis of Tpit in Poodle dogs with ACTH-dependent hyperadrenocorticism

There is a high incidence of pituitary-dependent hyperadrenocorticism (PDH) in Poodle dogs, with family members being affected by the disease, suggesting a genetic involvement. Tpit is an obligate transcription factor for the expression of pro-opiomelanocortingene and for corticotroph terminal differentiation. The aim of the present study was to screen the Tpit gene for germline mutations in Poodles with PDH. Fifty Poodle dogs (33 female, 8.71 +/- 2.8 years) with PDH and 50 healthy Poodle dogs (32 females, 9.4241 2.8 years) were studied. Genomic DNA was isolated from peripheral blood, amplified by PCR and submitted to automatic sequence. No mutation in the coding region of Tpit was found, whereas the new single nucleotide polymorphism p.S343G, in heterozygous state, was found in the same frequency in both PDH and control groups. We concluded that Tpit gain-of-function mutations are not involved in the etiology of PDH in Poodle dogs.

INFLUENZA VIRUSES IN ADULT DOGS RAISED IN RURAL AND URBAN AREAS IN THE STATE OF SAO PAULO, BRAZIL

In 1970, searching for the interspecies transmission of influenza viruses led to the first study on influenza viruses in domestic animals. Birds and mammals, including human beings, are their natural hosts; however, other animals may also play a role in the virus epidemiology. The objective was to investigate the incidence of influenza viruses in adult dogs raised in rural (9, 19.56%) and urban (37, 80.43%) areas in the state of Sao Paulo, Brazil. Dog serum samples were examined for antibodies to influenza viruses by the hemagglutination inhibition (HI) test using the corresponding antigens from the circulating viruses in Brazil. Dogs from rural areas presented antibodies to influenza A H3N2, and influenza A H7N7 and H3N8. In rural areas, dog sera displayed mean titers as 94.37, 227.88, 168.14, 189.62 HIU/25 mu L for subtypes H1N1, H3N2, H7N7, H3N8, respectively. About 84% and 92% of dogs from urban areas exhibited antibodies to human influenza A H1N1 and H3N2, respectively, with statistical difference at p < 0.05 between the mean titers of antibodies to H1N1 and H3N2. About 92% and 100% were positive for H7N7 and H3N8, respectively. In dogs from urban areas, the mean titers of antibodies against influenza A H1N1, H3N2, H7N7 and H3N8, were 213.96, 179.42, 231.76, 231.35 HIU/25 mu L respectively. The difference among them was not statistically significant at p > 0.05. In conclusion, these dogs were positive for both human and equine influenza viruses. The present study suggests the first evidence that influenza viruses circulate among dogs in Brazil.