Adult Male Dogs Research Articles

A Microscopic Study of the Aortic Branches Structure in the Adult Male Dog

The aim of the present study was to determine the structural changes between elastic and muscular artery in branches (ciliac artery, mesenteric artery, renal artery) of aorta. Five normal adult male dogs were studied and the specimens were processed in the routine way for light microscopy. It was established that the proximal part of the aortic branches contains parallel and fenestrated elastic fibers. These fibers decrease and become fragmented in the middle part of branches. In the distal part, the rows of smooth muscle cells are grater in number and the elastic fibers appear to be fragmented. Therefore the proximal part of branches shows a structure intermediate between those of elastic and muscular arteries. With coming toward to the distal part of the branches the elastic fibers reduce and these changes occur gradually.

Effects of xylazine-ketamine anesthesia on plasma levels of cortisol and vital signs during laparotomy in dogs

This study was designed to evaluate effects of xylazine-ketamine anesthesia on plasma levels of cortisol and vital signs during and after laparotomy in dogs. Eight clinically healthy, adult male dogs, weighing 20 kg were used. All dogs were initially sedated by acepromazine. Thirty minutes later, ketamine plus xylazine was used to induce anesthesia. Surgical incision of laparotomy was done. After a 5 min manipulation of the abdominal organs, the incision was sutured. Vital signs including heart rate, respiratory rate and rectal temperature (RT) were recorded at the times of -30: premedication, 0: induction and Surgical incision, 30: End of surgery, 60, 90 and 120 min. Blood was sampled at the above mentioned times and analyzed using a commercial ELISA kit for cortisol. A significant decreasing trend in RT was observed during the studied times. No significant changes were observed in heart rate and respiratory rate (p>0.05), except at the time of 60 respiratory rate significantly decreased when compared to the time of 90 (p=0.026) and 120 (p=0.041). A non-significant but increasing trend in plasma levels of cortisol was observed.

Utilisation d’implants sous-cutanés d’agonistes de la GnRH chez les carnivores domestiques pour maîtriser la reproduction

La mise récente sur le marché européen d’implants sous-cutanés contenant un agoniste de l’hormone hypothalamique GnRH, la desloréline, offre une alternative chimique à la castration chirurgicale du chien mâle adulte. Ces implants agissent sur la fonction endocrine (effondrement de la testostéronémie), sur la fonction exocrine (altération de la qualité du sperme et infertilité) et permettent un suivi de l’évolution clinique (diminution de la taille des testicules). Leur disponibilité a également ouvert la voie à de multiples autres indications dans les espèces canines et félines. Ils présenteraient un intérêt pour améliorer certains comportements gênants du mâle, potentiellement liés à la testostérone, pour bloquer la fertilité du chat mâle et éviter l’apparition de l’oestrus chez la chienne ou la chatte. L’implantation d’animaux pré-pubères dans le but de retarder la puberté semble efficace. Chez la chienne adulte, l’induction d’un oestrus induit post-implantation est même possible, ce qui présente un intérêt zootechnique. Toutefois, les effets secondaires potentiels, la durée d’action et la reprise de la fertilité après implantation ne sont pas encore bien connus et doivent être davantage étudiés.

Mesenchymal Stem Cells Home to but do not Modulate Acute Renal Injury in a Canine Model

Background: Acute kidney injury (ARI) is a common clinical event that occurs in 5-35% of all hospitalized patients and is associated with a two- to five fold increased mortality risk., with no significant improvement on pharmacologic therapy. The need for better treatment strategies for ARI called for cellular based strategies aiming to regenerate damaged tissues. Mesenchymal stem cells (MSCs) hold special promise in attenuating kidney injury, since nephrons are largely of mesenchymal origin. Objectives: The objective of this study is to evaluate the role of bone marrow derived (MSCs) in regeneration of post-ischemic acute renal injury in mongrel dogs. Material and Methods: Fifteen adult male mongrel dogs were used in this study. Animals were divided into: Group I, normal group (3 dogs); Group II, nine dogs subjected to ischemic/reperfusion injury (IRI) by clamping both renal pedicles for 60 minutes and not subjected to stem cell therapy which were further divided into: 6 dogs without sham injection, 3 sacrificed 3 days and 3 after 7 days after IRI and 3 dogs with sham injection sacrificed 7 days after IRI. and Group III (3 dogs) which underwent IRI and received systemic autologous MSC injection. This group underwent aspiration of 15-20 ml bone marrow from posterior iliac spine, mononuclear cell separation and MSC separation. MSCs were tagged by iron oxide and injected in a dose of 2million /kg systemically through the femoral vein. Evaluation of Therapeutic Effect: 1. Functional evaluation of renal functions using serum creatinine preoperative and 30 minutes, 1 day, 2days, 4days, 7days postoperative.2. Renal histology and injury scores: using H&E, PAS using morphometry. 3. Tracing of injected MSCs (homing) in renal tissues using Prussian blue staining . 4. Immunohistochemical evaluation of the apoptosis and proliferative capacity of MSCs using caspase3 and KI 67. Results: Bone marrow derived MSCs were found in the renal cortex and medulla, epithelial lining of the cortical tubules, glomeruli, the Bowman's space, in some peritubular capillaries and among the epithelial lining of the renal tubules of treated animals. However,MSCs did not undergo trans- differentiation to renal cells, There was no difference in the regeneration, apoptosis or proliferation between treated and non-treated animals. Conclusions: Injected MSCs homed to but did not affect regeneration of renal tissue after acute injury. Although MSCs did not prove to differentiate into renal tissue, they can be used as vehicles for cytokines or growth factors as they home to injured sites.

Laparoscopic Vasectomy vs Laparoscopic Sterilization in Dogs: A Comparison of Two Techniques

Twelve clinically healthy, adult male dogs randomly equally divided into two groups (I and II). Animals of both the groups received xylazine-ketamine anesthesia. Laparoscopic bilateral vasectomy was performed in group I, whereas in animals of group II in additition to vasectomy, spermatic artery-vein plexus were clipped with titanium clips at a distance of 1 to 2 cm. Insufflation of abdominal cavity was achieved by CO2 (2 liter/minute) at 10 mm Hg pressure gradient. Clinical observations revealed no significant changes. Differential leukocyte count (DLC) revealed significant neutrophilia and comparative lymphopenia on 3rd postoperative in both groups. Significant increase (p 0.05) up to 7th postoperative day in animals of group II. On the basis of the parameters studied, it can be concluded that capnoperitoneum at 10 mm Hg pressure gradient and CO2 at the flow rate of 2 liter/minute provides optimum visualization of intra-abdominal organs and found suitable for laparoscopic sterilization in male dogs. The laparoscopic vasectomy alone in male dogs was found comparatively quick, less time consuming and can be successfully applied for mass sterilization program. Oxidative stress in laparoscopic vasectomy (group I) was less as compared to other group.

Interdental Osteotomies Induce Regional Acceleratory Phenomenon and Accelerate Orthodontic Tooth Movement

Although it has been revealed clinically that double-jaw orthognathic surgery induces a systemic increase in the baseline bone turnover and subsequently accelerates postoperative orthodontic tooth alignment, it is not clear whether less extensive osteotomy, such as interdental osteotomy, would be intensive enough to accelerate postoperative orthodontic tooth alignment. Twelve adult male beagle dogs were randomly assigned to 2 groups. The sham control group (n = 6) received orthodontic tooth alignment of the maxillary incisors, and the experimental group (n = 6) received orthodontic tooth alignment of the maxillary incisors and interdental osteotomies between the maxillary third incisor and canine on both sides concurrent with the beginning of orthodontic tooth alignment. The duration of orthodontic tooth alignment was 3 months in both groups. Cone-beam computed tomography scans of the maxilla, dental casts, blood samples, and gingival crevicular fluid (GCF) of the maxillary incisors were taken immediately before orthodontic tooth alignment (T0) and 1 week (T1) and 1 (T2), 2 (T3), and 3 (T4) months after beginning orthodontic tooth alignment. They were analyzed for changes in the interdental alveolar bone gray scale (osteoporosity) of the maxillary incisors, irregularity index (rate of orthodontic tooth alignment), and bone-specific alkaline phosphatase (bALP, a biomarker of osteoblastic activity) and C-terminal telopeptide of type I collagen (ICTP, a biomarker for osteoclastic activity) in the serum and GCF samples from T0 to T4. The data were analyzed statistically for inter- and intragroup differences. The rate of orthodontic tooth alignment for the experimental group was significantly greater and twofold that of the sham control group at T1, T2, T3, and T4. The serum-bALP, serum-ICTP, GCF-bALP, GCF-ICTP, and osteoporosity remained similar from T0 to T4 in the sham control group. In contrast, GCF-bALP increased two- to threefold from T1 to T4, and GCF-ICTP increased fivefold at T1 and then gradually decreased from T2 to T4. The interdental osteoporosity significantly increased from T1 to T4, but the serum-bALP and serum-ICTP levels remained similar, without significant changes in the experimental group. Interdental osteotomy induced a regional, but not a systemic, acceleratory phenomenon and was intensive enough to accelerate postoperative orthodontic tooth alignment twofold. The intensity of the increase in the bone turnover rate and osteoporosity might depend on the extent of the osteotomy.

Modified cementless total coxofemoral prosthesis: development, implantation and clinical evaluation

The aim of this study was to modify canine coxofemoral prostheses and the clinical evaluation of the implantation. Fifteen canine hips and femora of cadavers were used in order to study the surface points of modification in prostheses and develop a perforation guide. Femoral stems and acetabular components were perforated and coated with biphasic calcium phosphate layer. Twelve young adult male mongrel dogs were implanted with coxofemoral prostheses. Six were operated upon and implanted with cemented canine modular hip prostheses, establishing the control group. The remaining six were implanted with a novel design of cementless porous tricalcic phosphate-hydroxyapatite coated hip prostheses. Clinical and orthopedic performance, complications, and thigh muscular hypotrophy were assessed up to the 120th post-operatory day. After 120 days, animals with cementless prostheses had similar clinical and orthopedic performance compared to the cemented group despite the increased pain thigh hypotrophy. Animals that underwent cementless hip prosthesis evidenced more pain, compared to animals with cemented hip prosthesis that required longer recuperation time. No luxations, two fractures and two isquiatic neurapraxies were identified in the course of the study. Using both the cemented and the bioactive coated cementless model were suitable to dogs, showing clinical satisfactory results. Osseointegration and biological fixation were observed in the animals with the modified cementless hip prosthesis.

Do stem cells promote healing of experimentally induced wound injury in adult male dogs? Histological and immunohistochemical study

Background Stem cells have generated considerable interest and promise as a potential source of cells for cell-based therapeutic strategies, primarily owing to their intrinsic ability to self-renew and differentiate into multiple functional cell types. Stem cells have been utilized to regenerate viable skin tissue. Aim of the work The present study was carried out to investigate the healing capacity of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) and its regenerative role in experimentally induced wound injury. Materials and methods The present study was carried out on 18 dogs. The study included two groups. Group I (n=6) was used a negative control and received no treatment. Group II was used as an experimental group and was divided into subgroup IIa (n=6), used as a positive control, and subgroup IIb (n=6). Subsequently, three circular wounds were made using a 10-mm diameter skin punch biopsy in the animals of subgroup IIa and subgroup IIb to induce wound injury. Group IIb were injected subcutaneously with undifferentiated mesenchymal stem cells at a dose of 1.4–1.6×106/ml in 5 ml sterile saline into the wound bed for 2 weeks after wound injury; skin biopsies from the wound areas were prepared for staining by H&E and immunostaining using anti-Thy-1 (CD90) antibodies. Results BM-MSC-treated wounds showed accelerated wound closure, with increased re-epithelialization of the epidermis, increased dermal cellularity and hair follicles, and angiogenesis. This was confirmed by the apparent increased immunoreactivity of the cell content of anti-rat Thy-1 CD90 cells in the dermis. Conclusion Asubcutaneous injection of autologous undifferentiated mesenchymal stem cells into the wound bed is an effective method of wound regeneration and can be used in chronic wounds as in a diabetic foot.

Cardiovascular, respiratory, electrolyte and acid–base balance during continuous dexmedetomidine infusion in anesthetized dogs

ObjectiveTo evaluate the cardiovascular, respiratory, electrolyte and acid–base effects of a continuous infusion of dexmedetomidine during propofol–isoflurane anesthesia following premedication with dexmedetomidine. Study designProspective experimental study. AnimalsFive adult male Walker Hound dogs 1–2 years of age averaging 25.4 ± 3.6 kg. MethodsDogs were sedated with dexmedetomidine 10 μg kg−1 IM, 78 ± 2.3 minutes (mean ± SD) before general anesthesia. Anesthesia was induced with propofol (2.5 ± 0.5 mg kg−1) IV and maintained with 1.5% isoflurane. Thirty minutes later dexmedetomidine 0.5 μg kg−1 IV was administered over 5 minutes followed by an infusion of 0.5 μg kg−1 hour−1. Cardiac output (CO), heart rate (HR), ECG, direct blood pressure, body temperature, respiratory parameters, acid–base and arterial blood gases and electrolytes were measured 30 and 60 minutes after the infusion started. Data were analyzed via multiple linear regression modeling of individual variables over time, compared to anesthetized baseline values. Data are presented as mean ± SD. ResultsNo statistical difference from baseline for any parameter was measured at any time point. Baseline CO, HR and mean arterial blood pressure (MAP) before infusion were 3.11 ± 0.9 L minute−1, 78 ± 18 beats minute−1 and 96 ± 10 mmHg, respectively. During infusion CO, HR and MAP were 3.20 ± 0.83 L minute−1, 78 ± 14 beats minute−1 and 89 ± 16 mmHg, respectively. No differences were found in respiratory rates, PaO2, PaCO2, pH, base excess, bicarbonate, sodium, potassium, chloride, calcium or lactate measurements before or during infusion. Conclusions and clinical relevanceDexmedetomidine infusion using a loading dose of 0.5 μg kg−1 IV followed by a constant rate infusion of 0.5 μg kg−1 hour−1 does not cause any significant changes beyond those associated with an IM premedication dose of 10 μg kg−1, in propofol–isoflurane anesthetized dogs. IM dexmedetomidine given 108 ± 2 minutes before onset of infusion showed typical significant effects on cardiovascular parameters.

Myocardial remodeling and bioelectric changes in tachycardia-induced heart failure in dogs

In this study, electrical and structural remodeling of ventricles was examined in tachycardia-induced heart failure (HF). We studied two groups of weight-matched adult male mongrel dogs: a sham-operated control group (n=5) and a pacing group (n=5) that underwent ventricular pacing at 230 bpm for 3 weeks. Clinical symptoms of congestive HF were observed in both groups. Their hemodynamic parameters were determined and the severity of the HF was evaluated by M-mode echocardiography. Changes in heart morphology were observed by scanning electron and light microscopy. Ventricular action potential duration (APD), as well as the 50 and 90% APD were measured in both groups. All dogs exhibited clinical symptoms of congestive HF after rapid right ventricular pacing for 3 weeks. These data indicate that rapid, right ventricular pacing produces a useful experimental model of low-output HF in dogs, characterized by biventricular pump dysfunction, biventricular cardiac dilation, and non-ischemic impairment of left ventricular contractility. Electrical and structural myocardial remodeling play an essential role in congestive HF progression, and should thus be prevented.

Refrigeração do epidídimo canino a 4ºC e recuperação dos espermatozoides epididimários utilizando ACP-106c

Objetivou-se avaliar a qualidade dos espermatozoides recuperados da cauda do epidídimo após a refrigeração do complexo testículo-epidídimo (CTE) de cães usando o diluidor ACP-106c. Foram utilizados 60 cães machos adultos, com peso de 10-20 kg. Após a eutanásia, removeu-se o CTE que foi imerso em solução fisiológica 0,9% e transportado em caixa térmica ao laboratório a 30ºC. Para a refrigeração e recuperação dos espermatozoides epididimários, os 60 pares do CTE foram divididos em 4 grupos, de acordo com o tempo de refrigeração do CTE e posterior recuperação espermática: G0h, G6h, G12h e G18h, em que cada par do CTE permaneceu por zero, seis, doze ou dezoito horas a 4ºC, respectivamente. A recuperação dos espermatozoides da cauda do epidídimo foi realizada pela técnica de flutuação utilizando-se o diluidor ACP-106c ou Tris. Para cada epidídimo foi adicionado 1,0 mL de um dos dois diluidores, pré-aquecidos a 37ºC por 5 minutos. Em seguida foram centrifugados a 800g/5 minutos para remoção dos resíduos celulares. Avaliou-se a morfologia, funcionalidade e motilidade espermática total e progressiva, além de parâmetros obtidos pelo CASA. Os dados foram submetidos à ANOVA seguido do teste de Turkey (P < 0,05). Em todos os parâmetros avaliados, não houve diferença entre os diluidores testados (P>0,05). Os valores de motilidade total nos grupos G0h, G6h, G12h, e G18h para o ACP-106c foram 84,4±7,7; 81,6±11,6; 88,3±6,5 e 69,5±16,9, respectivamente, e para o Tris 85,2±8,7; 77,4±14,3; 79,0±17,8 e 65,4±17,9, respectivamente. Um decréscimo na qualidade espermática foi observado após 18 horas de refrigeração em ambos os diluidores. Dessa forma pode-se concluir que o ACP-106c pode ser utilizado para recuperar os espermatozoides epididimários refrigerados e podem ser viáveis por até 12h de refrigeração.

Transarterial prostatic embolization:initial experience in hormone-induced benign prostatic hyperplasia in dogs

Objective To evaluate the feasibility of transarterial prostate embolization for reducing the volume and its technical safety in hormone-induced dogs prostate hyperplasia. Methods Prostate hyperplasia was induced on 12 adult male dogs by administering testosterone propionate for 12 weeks.Then,the dogs were randomly assigned to transarterial prostatic embolization group (n=6) and control group (n=6).Twelve weeks after initiating the hormone treatment,6 animals in transarterial prostatic embolization group underwent prostatic arterial embolization with Embospheres 100—300μm in diameter.Based on MRI,the volume of prostate was measured for both groups on the three time points: before injection of hormone (BI),before the procedure of prostatic arterial embolization (BP) and 12 weeks after the procedure of prostatic arterial embolization (AP).Finally,the prostates and surrounding tissues were harvested for histopathology study.A statistical software package (SPSS version 19.0) was used for analysis.Measurement data were expressed as x± s.Samples paired t test was used to compare the prostatic volume between BP and AP.The t test was applied in the intergroup comparison.P<0.05 was considered to indicate a statistically significant difference. Result s The successful rate of BPH model establishment and superselective catheterization were 100%.No serious procedure-related complication was observed.After 12 weeks of hormone administration,the mean volume of prostate was 19.5±2.5 mm3in embolization group and 19.2±3.8 mm3in control group before prostatic arterial embolization,without statistical difference (t=0.14,P>0.05).At 12 weeks after prostatic arterial embolization,the mean volume of prostate was 6.1±1.4 mm3in embolization group and 17.8±3.5 mm3in control group with significant statistical difference (t=-7.6,P 0.05).Histopathology study revealed that embosphere particles had occluded partial arterioles of the prostate in the embolization group of dogs.Near the occluded arterioles,normal gland structure disappeared; while residual gland tissue appeared to be atrophied.In embolization group,there was no gross or microscopic change in the surrounding tissues including bladder,deferent duct and rectum.Extensive prostate glandular hyperplasia was observed in control group. Conclusions Transcatheter arterial embolization is feasible for reducing prostate volume without serious complication in hormone-induced prostate hyperplasia dogs and worthy of further investigation. Key words: Prostatic hyperplasia; Embolization,therapeutic; Angiography,digital subtraction;Animals,laboratory

English

To monitor the effects of a double dose of non-ionic contrast agent administered intravenously (iv) to anesthetized dogs, on the major functions and the biochemical and hematological parameters, two non-ionic contrast agents were tested (Optiray 350 and Ultravist 370) on two lots of 15 adult male and female dogs. The administered dose was 7 ml/kg and the recommended dose was 3.5 ml/kg. Several biochemical and hematological parameters were determined at 15, 60 min and 24 h after administration of contrast agents. Blood urea nitrogen (BUN) and bilirubin (BILI) had a statistical significance at F &lt; 0.05 in values ​​measured after 15 min, and statistical significance at p &lt; 0.001 were obtained for aspartate aminotransferase (AST) and BILI. Statistical significance at F &lt; 0.05 for the parameters measured after 60 min were BILI and AST, and statistical significance of values at p &lt; 0.001 was obtained for the same parameters. Within 48 h of substance administration, the values ​​of the tested parameters came back within physiological limits. Administration of contrast substance in double dose did not produce changes in pulse, body temperature and respiratory rate. &nbsp; Key words:&nbsp;Non-ionic contrast medium, dog,&nbsp;blood chemical analysis,&nbsp;administration, intravenous.

Early Enhanced External Counter Pulsation Improves Neurological Recovery After the Return of Spontaneous Circulation in a Mongrel Dog Cardiac Arrest Model*

The aim of this study was to investigate whether early enhanced external counter pulsation therapy after cardiopulmonary resuscitation improved neurological outcome in a mongrel dog cardiac arrest model. Randomized, animal study. Assisted circulation laboratory. Twenty-four healthy male adult dogs (12-14 kg). After minutes of untreated ventricular fibrillation followed by 2 minutes of cardiopulmonary resuscitation, the dogs were randomized to receive 4 hours of enhanced external counter pulsation therapy, to receive 4 hours of hypertension with over 140 mm Hg or to be a control. Blood pressure and left ventricular ejection fraction were recorded. Cerebral flow was assessed using magnetic resonance imaging. Arterial blood gases and endothelium-derived vasoactive substances were assessed before cardiac arrest and 4 hours after the return of spontaneous circulation. Neurological outcome was assessed by the neurologic deficit score and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining. Enhanced external counter pulsation significantly improved the left ventricular ejection fraction and increased common carotid artery blood flow and shear stress. Enhanced external counter pulsation increased both relative cerebral blood volume (RCBV, p = 0.043) and relative cerebral blood flow (RCBF, p = 0.012) in animals 4 hours after return of spontaneous circulation. Enhanced external counter pulsation therapy promoted the production of nitric oxide and tissue plasminogen activator and decreased the release of endothelin-1 (p = 0.013) after return of spontaneous circulation. Treatment with norepinephrine in the high mean artery pressure also increased common carotid artery blood flow and shear stress. However, no effects on the left ventricular ejection fraction, the production of nitric oxide and tissue plasminogen activator, or the release of endothelin-1 were found. The neurologic deficit scores of the animals were significantly lower at 24, 48, 72, and 96 hours in the enhanced external counter pulsation group, as well as at 24, 72, and 96 hours compared with animals in the control group after return of spontaneous circulation. Fewer apoptotic neurons were observed in the animals in the enhanced external counter pulsation group compared with the animals in the control and hypertension groups. These data indicated that the treatment of early enhanced external counter pulsation improved neurological outcome by both increasing cerebral blood flow and improving the recovery of microcirculation after return of spontaneous circulation. The treatment of early enhanced external counter pulsation can be a good option for protecting the brain after return of spontaneous circulation.

Evaluation of a compression resistant matrix for recombinant human bone morphogenetic protein‐2

Previous studies document the therapeutic potential of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier for indications in the axial and appendicular skeleton. Nevertheless, the ACS does not comprise structural integrity to adequately support bone formation for onlay indications. The objective of this study was to evaluate local bone formation and osseointegration following surgical implantation of rhBMP-2 soak-loaded onto a compression resistant matrix (CRM). Routine, contralateral, critical-size, supraalveolar, peri-implant defects in five adult male Hound Labrador mongrel dogs received 0.8mg rhBMP-2 soak-loaded onto either the ACS (benchmark control) or a CRM (collagen/β-TCP/hydroxyapatite) followed by submerged wound closure for primary intention healing. The animals were euthanized at 8weeks for histologic/histometric evaluation. Healing was uneventful albeit considerable initial swelling was observed for either treatment. Sites receiving rhBMP-2/CRM showed significantly increased bone area (20.0±0.9 versus 12.3±2.6mm(2) , p=0.03) and bone density (24.1±1.4% versus 14.6±2.0%, p=0.04) compared with those receiving rhBMP-2/ACS. There were no significant differences between treatments for new bone height and osseointegration. Woven and lamellar trabecular bone lined with abundant osteoid was observed for all sites. Inconsistent cortex formation confirmed the immature nature of the newly formed bone. Seroma formation was observed for both treatments (80-100% of the animals/implants). Sites receiving rhBMP-2/CRM showed residual ceramic granules undergoing biodegradation, including accumulation of foamy macrophages. rhBMP-2/CRM supports bone formation of clinically relevant geometry. Longer observation intervals as well as dose variations appear necessary to capture maturation of the newly formed bone, elimination of residual ceramic granules and resolution of seroma formation(s).

Canine body composition quantification using 3 tesla fat–water MRI

To test the hypothesis that a whole-body fat-water MRI (FWMRI) protocol acquired at 3 Tesla combined with semi-automated image analysis techniques enables precise volume and mass quantification of adipose, lean, and bone tissue depots that agree with static scale mass and scale mass changes in the context of a longitudinal study of large-breed dogs placed on an obesogenic high-fat, high-fructose diet. Six healthy adult male dogs were scanned twice, at weeks 0 (baseline) and 4, of the dietary regiment. FWMRI-derived volumes of adipose tissue (total, visceral, and subcutaneous), lean tissue, and cortical bone were quantified using a semi-automated approach. Volumes were converted to masses using published tissue densities. FWMRI-derived total mass corresponds with scale mass with a concordance correlation coefficient of 0.931 (95% confidence interval = [0.813, 0.975]), and slope and intercept values of 1.12 and -2.23 kg, respectively. Visceral, subcutaneous and total adipose tissue masses increased significantly from weeks 0 to 4, while neither cortical bone nor lean tissue masses changed significantly. This is evidenced by a mean percent change of 70.2% for visceral, 67.0% for subcutaneous, and 67.1% for total adipose tissue. FWMRI can precisely quantify and map body composition with respect to adipose, lean, and bone tissue depots. The described approach provides a valuable tool to examine the role of distinct tissue depots in an established animal model of human metabolic disease.

Effects of Trypanosoma brucei infection and diminazene aceturate therapy on testicular morphology and function of Nigerian local dogs

The effects of Trypanosoma brucei infection on testicular morphology and function and the changes associated with treatment of infected dogs with diminazene aceturate were studied using fifteen Nigerian adult male dogs. The dogs were randomly assigned into three groups A, B and C consisting of five dogs each. Groups A and B were infected with 1×106 trypanosomes and group C was the uninfected control. Following infection, parasitaemia levels were monitored daily whereas the rectal temperature, body weight, packed cell volume, scrotal circumference and serum testosterone levels were monitored weekly. At parasitaemia peak, dogs in group A were orchidectomised while dogs in group B were treated with 7.0mg/kg body weight of diminazene aceturate (DA). Dogs in groups B and C were later orchidectomised on day 73 of the experiment. The harvested testes and epididymides were weighed and the epididymal sperm reserves of all the dogs determined. Also the sperm quality (mass activity, sperm motility and sperm morphology) were determined. The testes were sectioned after processing and studied histomorphologically. Acute trypanosomosis was observed following infection. The low serum testosterone levels observed from day 14 post infection (pi) gradually improved following treatment. Testicular weight, epididymal weight and sperm quality were significantly low (p<0.05) in the infected dogs when compared to the control group but gradually improved following treatment. Histomorphological studies revealed testicular degeneration characterized by depopulation of seminiferous tubules and depletion of spermatogenic cells in dogs of group A whereas the tissue sections of the testes of dogs in group B were similar to those of the control group. It was therefore concluded that infection of dogs with T. brucei adversely affected testicular morphology and function. Treatment with diminazene aceturate reversed the reproductive abnormalities caused by the parasite.

Comparative Study of Chinese Hamster Ovary Cell Versus Escherichia coli‐Derived Bone Morphogenetic Protein‐2 Using the Critical‐Size Supraalveolar Peri‐Implant Defect Model

Chinese hamster ovary (CHO) cell-derived recombinant human bone morphogenetic protein-2 (rhBMP-2) has been introduced for spine, long bone, and craniofacial indications. Escherichia coli- (E. coli) derived rhBMP-2 displays comparable efficacy to CHO cell-derived rhBMP-2 in vitro and in small-animal models. The objective of this study is to evaluate the efficacy of E. coli-derived rhBMP-2 compared to the benchmark CHO cell-derived rhBMP-2 using an established large-animal model. Contralateral, critical-size supraalveolar peri-implant defects in six adult male Hound Labrador mongrel dogs received CHO cell- or E. coli-derived rhBMP-2 (0.2 mg/mL) in an absorbable collagen sponge (ACS) carrier. In each quadrant, three dental implants were placed. A titanium mesh device was used to support space provision. The animals received fluorescent bone markers for qualitative evaluations. Animals were euthanized at 8 weeks for histopathologic and histometric evaluation. Clinical healing included significant swelling, but none of the animals experienced wound dehiscences. CHO cell- and E. coli-derived rhBMP-2 supported comparable bone formation (new bone area, 35.8 ± 3.6 versus 30.1 ± 2.2 mm(2); bone density, 31.8% ± 1.6% versus 35.6% ± 2.5%; and osseointegration, 32.9% ± 7.4% versus 33.7% ± 8.1%) without statistically significant differences between treatments. Newly formed immature delicate trabecular bone in fibrovascular marrow filled the space underneath the titanium mesh and extended coronally above the mesh. Seroma formation was frequently observed. There were no discernable qualitative histologic differences between treatments. CHO cell- and E. coli-derived rhBMP-2 in an ACS carrier appear equally effective at inducing local bone formation in support of dental implant osseointegration.

Estudo comparativo entre os fios de algodão, poliglactina e poliglecaprone nas anastomoses intestinais de cães

Over the years, many sutures were developed and then abandoned. Until now was not found an ideal suture to the intestinal tract or other tissues in general, making the choice a difficult task. To evaluate, macroscopically and microscopically, the healing process of intestinal anastomoses in dogs using polyglecaprone 25, polyglactin 910 and cotton sutures. Twenty adult male dogs were operated on and underwent to three small bowel anastomosis using the technique with submucosal sutures. Were used three threads and the anastomoses were evaluated at different postoperative periods - group I - three days; group II - seven days; group III - 14 days and group IV - 21days. Macroscopic analysis was to assess the presence or absence of peritonitis, aspect of the anastomosis and adhesions. Histological studies of the anastomoses, using hematoxylin and eosin and Masson's trichrome analyzed the exudative inflammation, granulomatous inflammation, the mucosal epithelial coating and collagen fibers. The macroscopic analysis showed good coaptation of the edges with a moderate degree of adhesion between the intestines and omentum three to 21 days after surgery. The microscopic evaluation revealed exudative inflammation with neutrophils and fibrin, which ranged from mild to moderate until the 14th day; granulomatous inflammation with macrophages, multinucleated giant cells and epithelioid cells were more evident at 14th day for the cotton, presence of granulation tissue (fibroblasts) and collagen fibers, a moderate way, from the 7th for the three threads. All three threads showed similar behavior and thus they can be indicated for anastomoses of the small intestine.

A novel canine model for prostate cancer

No existing animal model fully recapitulates all features of human prostate cancer. The dog is the only large mammal, besides humans, that commonly develops spontaneous prostate cancer. Canine prostate cancer features many similarities with its human counterpart. We sought to develop a canine model of prostate cancer that would more fully represent the features of human prostate cancer than existing models. The Ace-1 canine prostate cancer cell line was injected transabdominally under transrectal ultrasound (TRUS) guidance into the prostates of immunosuppressed, intact, adult male dogs. Tumor progression was monitored by TRUS imaging. Some dogs were subjected to positron emission tomography (PET) for tumor detection. Time of euthanasia was determined based on tumor size, impingement on urethra, and general well-being. Euthanasia was followed by necropsy and histopathology. Ace-1 tumor cells grew robustly in every dog injected. Tumors grew in subcapsular and parenchymal regions of the prostate. Tumor tissue could be identified using PET. Histological findings were similar to those observed in human prostate cancer. Metastases to lungs and lymph nodes were detected, predominantly in dogs with intraprostatic tumors. We have established a minimally invasive dog model of prostate cancer. This model may be valuable for studying prostate cancer progression and distant metastasis.