Mature Dogs Research Articles

PIWIL1 Is Expressed in the Canine Testis, Increases with Sexual Maturity, and Binds Small RNAs.

Spermatogenesis is a highly regulated process leading to the development of functional spermatozoa through meiotic division and subsequent maturation. Recent studies have suggested that a novel class of Argonaute proteins, known as the PIWI clade, plays important roles in multiple stages of spermatogenesis. PIWI proteins bind specific small noncoding RNAs, called PIWI-interacting RNAs (piRNAs). These piRNAs guide the PIWI-piRNA complex to retrotransposon targets that become expressed during meiosis. Retrotransposons are subsequently silenced, either through PIWI "slicer" activity or through PIWI-directed methylation of the retrotransposon locus. Most mammalian studies have employed mouse models where sterility follows PIWI inactivation. The goal of this study was to characterize canine PIWIL1 to determine whether expression pattern and functional characteristics support a similar function in that species. Canine PIWIL1 cDNA is a 2.6-kb transcript that encodes an 861-amino acid protein showing high homology to other mammalian PIWIL1 proteins and containing features consistent with PIWI family members (PAZ, PIWI domains). Analysis of PIWIL1 protein and transcript levels revealed that PIWIL1 expression is limited to the testes and is associated with sexual maturity, with mature dogs showing higher levels of PIWIL1 expression. Immunohistochemistry demonstrated expression primarily in seminiferous tubules and confirmed higher levels of PIWIL1 in mature dogs. Functional characterization by RNA immunoprecipitation demonstrated that canine PIWIL1 binds short RNAs consistent in size with piRNAs (27-32 nucleotides). Together, these studies represent the first characterization of a PIWI protein in the dog and suggest that it is a functional piRNA-binding protein most highly expressed in the mature testes.

HISTOLOGY AND ELECTRONE MICROSCOPIC STUDY OF THE EFFECTS OF AN GnRH AGONIST ON THE CANINE TESTIS AND PROSTATE AFTER 3 MONTHS OF TREATMENT

Using light and electrone microscopic techniques the structure of the testicle, epididymis and prostate gland of mature male dogs were studied 3 months after implantation with a slow release implant containing 6 mg GnRH agonist deslorelin. After 3 months of treatment, all tubules seminiferous showed atropic and aspermatogenic. Atrophy of the Leydig cells was observed in the interstitial tissue. The glandular epithelium of the prostate showed atrophy and was non secretory. At the electrone microscopic levels, Sertoli and Leydig cells showed a marked atrophy and their spermatogenic tubules were mostly lined with Sertoli cells at the basal lamina. The prostate gland showed atrophy of the nucleous and the epithelium was non secretory. The present data showed that a slow release implant containing GnRH agonist deslorelin can be used effectively to suppress fertility in male dogs.

Optimising femoral-head osteochondral allograft transplantation in a preclinical model

SummaryBackground/ObjectiveOsteochondral autografting and allografting of the femoral head have been described as treatments for avascular necrosis without segmental collapse, fracture, osteochondritis dissecans, and tumours. One long-term study reported that 80% of nonsteroid-treated patients had successful outcomes. Most data are compiled from small case reports or series. Although these results are encouraging, to the authors’ knowledge, there is no basic scientific evidence regarding optimal graft source or technique reported in the peer-reviewed literature. The objective of this study was to create a translational canine model to compare femoral-head osteochondral autografts and allografts with respect to safety and efficacy.MethodsWith Institutional Animal Care and Use Committee approval, skeletally mature hound-mix dogs (n = 6) weighing >20 kg underwent aseptic surgical implantation of osteochondral grafts using a craniolateral approach to the hip, without dislocation. Three graft options were evaluated: small auto (n = 3), 6-mm-diameter autograft from the trochlear ridge of the ipsilateral knee; small allo (n = 3), 6-mm-diameter fresh (21-day storage) allograft from a size-matched canine femoral head; or large allo (n = 3), 14-mm-diameter fresh (21-day storage) allograft from a size-matched canine femoral head. Small grafts were implanted into the same femoral head of three dogs, and large grafts were implanted alone in the other three dogs. The dogs were allowed unrestricted activity in their runs, and were walked on a leash for 15 minutes 5 times/wk. The outcome measures included functional, radiographic, and arthroscopic assessments at 8 weeks, and functional, chondrocyte viability, and histologic assessments at 6 months after surgery. The pre- and postoperative data were compared for statistically significant (p < 0.05) differences. Based on data from the canine study, four human patients underwent fresh (<28-day storage) osteochondral allografting using large (>30-mm diameter) size-matched femoral-head grafts. The radiographic, quality of life, and functional assessments were captured postoperatively.ResultsAll grafts had >80% chondrocyte viability at the time of implantation. All grafts showed radiographic evidence for integration into host bone. Small auto and small allo showed significant (p < 0.05) loss in range of motion, chondrocyte viability, and articular-cartilage integrity 8 weeks after implantation, whereas large allo maintained viability and structural integrity throughout the study period. The large-allo dogs maintained full hip range of motion and hindlimb function. A similar type of large allograft (>30 mm) was performed in the four human patients. Due to the defect size, three out of the four human patients required two large allografts at the time of implantation. At the time of this manuscript's acceptance, patient follow-up ranged from 4 months to 18 months. All human patients were full weight-bearing without an assistive device, and showed no evidence of graft failure or progressive arthrosis.ConclusionThese data provide initial translational and clinical evidence for large osteochondral allografts as a potential option for functional resurfacing of full-thickness cartilage defects of the femoral head.

SEM Study of Hair Cuticle in Some Canidae Breeds

Hair fibre study is very actual due to its implications especially in forensic medical expertise. The usual and SEM microscopic morphology of primary hair fibres collected from mature male dogs of five well-known breeds: Husky, Bichon Maltese, Golden retriever, Labrador and German Shepherd were studied. Descriptive observations and quantitative data obtained by micrometry do not lead to significant differences to permit identification of one breed by simple hair examination. Nonetheless, comparing the quantitative parameters of hair fibre obtained in our study with those known in specialty literature on human hair, we can conclude that there are differences among medullary index values and the index could be an identification criterion.

Canine nutrition for a healthy old age

Ageing dogs are commonly seen in veterinary practices. Small breed dogs may be considered geriatric at 12–14 years whereas large and giant breed dog would be geriatric at 7–9 years. When dogs begin to transition from adult to senior or geriatric, it is important that their nutrition is monitored by a veterinary professional so that they maintain health and a high quality of life. The veterinary nurse plays an important role in monitoring patients from the time they are puppies through their senior years assuring that appropriate nutrition is maintained for a long, healthy life. The veterinary nurse's role in helping the owner to achieve his or her goals of having a healthy older dog begins the minute the patient enters the clinic for the first time. Mature dogs are more prone than younger dogs to certain disease processes such as obesity, degenerative joint disease, cognitive dysfunction, and cardiac, renal, liver, and metabolic diseases. A beneficial feeding plan should be based on risk factors and any disease process affecting the individual dog. The aim is to establish a long healthy old age for the canine.

Results of the study of some biochemical values in dog after spaying

It is sometimes necessary to remove gonad of a dog during various age. In order to define the optimal age for spaying (ovariohysterectomy) female dogs, our study objectives were to investigate changes of hormonal and biochemical values in both immature and mature female dogs after spaying. Results of the study on sex hormone levels at different stages of female dog estrous cycle and biochemical values of only mature dogs were presented in this article. Highest progesterone concentration in female puppy occurs during diestrus (20-35 ng/ml), and estradiol level peaked (25-35 pg/ml) during proestrus. In mature dogs for one year after ovariohysterectomy, total proteins in plasma increased by 13.3%, albumin elevated by 31.1%, total lipids by 2.3 times, cholesterol by 3 times and plasma glucose by 2.3 times. Results of the study revealed removal of gonads or ovaries in female dogs leads to greater changes of metabolism, especially lipid or cholesterol metabolism disturbs at highest levelsMongolian Journal of Agricultural Sciences Vol.15(2) 2015; 16-21

МОРФОЛОГІЧНІ І БІОХІМІЧНІ ПОКАЗНИКИ КРОВІ СЛУЖБОВИХ СОБАК В ПОСТНАТАЛЬНОМУ ПЕРІОДІ ОНТОГЕНЕЗУ

The article presents the morphological and some biochemical parameters of blood of dogs in postnatal ontogeny (1, 7, 14 day, 1, 2, 8, 12 months and 3 years old), grown yield under nursery in conditions of Zhytomyr. The content of hemoglobin and number of erythrocytes in the blood of dogs, starting 1 day after birth, increases to 8–month age and almost on the same level in young and adult dogs 3 – 4 years of age. The least content of hemoglobin was diagnosed in puppies, 1, 7, 14 days and 2 months of age, and the greatest – in dogs 3 – 4 years of age. The number of erythrocytes in the blood of dogs, grown yield under nursery conditions were changed depending on age. The least number of erythrocytes was diagnosed in puppies, 1–,7– and 14–days age, and the highest in mature dogs, 8 and 12 month age. The number of erythrocytes in the blood of these animals was significantly (p &lt; 0.01) more, than bathed in puppies of previous age groups. Average value of the number of leukocytes in dogs in postnatal ontogeny was in the normal range and did not differ from all age group.The content of total protein in blood of dogs varied with age. The least content of it diagnosed in dogs 14 days of age, and the highest in dogs 3 – 4 years of age. The difference was significant (p &lt; 0.01). Albumin content in the blood of dogs of different age groups was normal and did not differ significantly. The content of bilirubin, urea and creatinine in the blood of dogs in a postnatal period of ontogenesis was also within normal limits and were not significantly different in dogs of different age groups.

Impact of the canine double-deletion β1 adrenoreceptor polymorphisms on protein structure and heart rate response to atenolol, a β1-selective β-blocker.

β-Adrenergic receptor antagonists are widely utilized for the management of cardiac diseases in dogs. We have recently identified two deletion polymorphisms in the canine adrenoreceptor 1 (ADRB1) gene.We hypothesized that canine ADRB1 deletions would alter the structure of the protein, as well as the heart rate response to the β-adrenergic receptor antagonist, atenolol. The objectives of this study were to predict the impact of these deletions on the predicted structure of the protein and on the heart rate response to atenolol in a population of healthy adult dogs. Eighteen apparently healthy, mature dogs with (11) and without (seven) ADRB1 deletions were evaluated. The heart rate of the dogs was evaluated with a baseline ambulatory ECG before and 14-21 days after atenolol therapy (1 mg/kg orally q12 h). Minimum, average, and maximum heart rates were compared between groups of dogs (deletions, controls) using an unpaired t-test and within each group of dogs using a paired t-test. The protein structure of ADRB1 was predicted by computer modeling. Deletions were predicted to alter the structure of the ADRB1 protein. The heart rates of the dogs with deletions were lower than those of the control dogs (the average heart rates were significantly lower). ADRB1 deletions appear to have structural and functional consequences. Individual genome-based treatment recommendations could impact the management of dogs with heart disease.

Sperm quality and selected biochemical parameters of seminal fluid in dogs with benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) in dogs is most commonly associated with age and increasing concentrations of dihydrotesterone, a hormone that stimulates growth and secretion of the prostatic epithelial cells. During this process, the biochemical composition of prostatic secretion changes, which can affect the quality of semen and limit the ability of the sperm to contribute to fertilization. Therefore, the present study was conducted to examine possible correlation between BPH and biological quality of semen. The study was performed in 11 sexually mature dogs of various breeds. Animals were divided into two groups: healthy dogs (Group I; n=5; mean age 4.32; SEM=1.28) and dogs with BPH (Group II n=6; mean age 6.16; SEM=0.65). Semen and prostate secretions were collected and evaluated in this study. Standard semen examinations were conducted in the ejaculates collected; moreover, the extent of apoptosis and DNA defragmentation was determined. The selected biochemical parameters were determined in the prostate secretion. According to the examination results, there were no significant differences in standard semen parameters between the two groups of dogs. Nevertheless, morphological tests of semen in dogs with BPH demonstrated elevated percentages of primary defects in spermatozoa. A significant increase (P=0.01) in DNA defragmentation of sperm was found in dogs with BPH. Moreover, changes in the biochemical composition of prostate secretion were demonstrated. In dogs with BPH, pH of prostate secretions was greater (P=0.03), concentrations of cholesterol increased while concentrations of Zn and Cu decreased. The study findings reveal that BPH does not change semen quality in dogs.

Measurement of the Tibial Plateau Angle in Normal Small Breed Dogs

This study measured the tibial plateau angle (TPA), a value that predicts cranial cruciate ligament rupture (CCLR) and a prerequisite for dynamic stabilization, in small breed dogs. The cadavers of 32 skeletally mature small breed dogs without CCLR were used to measure TPA. Differences were evaluated between males and females, left and right limbs, and among breeds. The mean TPA of all dogs was 26.13°± 2.33°. The mean TPAs of left and right limbs were 26.00°± 2.23° and 26.26°± 2.45°, respectively, which was not a significant difference. The mean TPAs of male and female dogs were 26.01°± 1.57° and 26°.22 ± 2.80°, respectively, which was also not significant difference. The mean TPAs in Maltese, Poodle, Shih Tzu, and Yorkshire terrier were 26.06°± 2.96°, 25.21°± 1.38°, 26.65°± 2.96°, and 26.27°± 1.61°, respectively. Differences in these means were not statistically significant. The TPA measured from this study could provide important information for further investigation of the pathogenesis of and surgical techniques for CCLR in small breed dogs.

Implant design and its effects on osseointegration over time within cortical and trabecular bone

Healing chambers present at the interface between implant and bone have become a target for improving osseointegration. The objective of the present study was to compare osseointegration of several implant healing chamber configurations at early time points and regions of interest within bone using an in vivo animal femur model. Six implants, each with a different healing chamber configuration, were surgically implanted into each femur of six skeletally mature beagle dogs (n = 12 implants per dog, total n = 72). The implants were harvested at 3 and 5 weeks post-implantation, non-decalcified processed to slides, and underwent histomorphometry with measurement of bone-to-implant contact (BIC) and bone area fraction occupied (BAFO) within healing chambers at both cortical and trabecular bone sites. Microscopy demonstrated predominantly woven bone at 3 weeks and initial replacement of woven bone by lamellar bone by 5 weeks. BIC and BAFO were both significantly increased by 5 weeks (p < 0.001), and significantly higher in cortical than trabecular bone (p < 0.001). The trapezoidal healing chamber design demonstrated a higher BIC than other configurations. Overall, a strong temporal and region-specific dependence of implant osseointegration in femurs was noted. Moreover, the findings suggest that a trapezoidal healing chamber configuration may facilitate the best osseointegration. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1091-1097, 2016.

Relationship between lean body mass and serum renal biomarkers in healthy dogs.

BackgroundSymmetric dimethylarginine (SDMA) is an accurate and precise biomarker for estimating glomerular filtration rate (GFR) in humans and cats. Serum creatinine (sCr) also correlates with GFR, but has limitations as a biomarker of renal function because nonrenal factors can influence its concentration.HypothesisDifferences in lean body mass (LBM) influence sCr, but not serum SDMA concentrations.AnimalsForty‐one healthy Beagles, mean age 9.9 years (range: 3.1–14.8 years), were studied over a 6 month period.MethodsSerum biomarkers of renal function were measured prospectively at baseline, and 1, 3, and 6 months. SDMA concentrations were measured by liquid chromatography‐mass spectroscopy and sCr concentrations by enzymatic colorimetry. Body composition was determined by dual energy x‐ray absorptiometry.Results LBM (P < .001) and age (P = .006) were significant explanatory variables for sCr concentration (R 2 = 0.38), but not SDMA concentration. Time on food was the only significant explanatory variable for SDMA concentration (R 2 = 0.49). SDMA concentrations decreased across time (P < .001). LBM was affected by sex (males > females; P = .02). Mature adult dogs (<8 years) had greater LBM compared with geriatric dogs (≥8 years; P < .001).Conclusion and Clinical Importance sCr concentrations, but not SDMA concentrations, are influenced by LBM, which limits sCr utility as a biomarker for monitoring renal function in dogs with decreased LBM. Reductions in LBM can lower sCr concentration and overestimate GFR. SDMA concentrations, but not sCr concentrations were influenced by time on food. SDMA could have clinical advantages over sCr in monitoring response to nutritional interventions.

In Vivo UTE-MRI Reveals Positive Effects of Raloxifene on Skeletal-Bound Water in Skeletally Mature Beagle Dogs.

Raloxifene positively affects mechanical properties of the bone matrix in part through modification of skeletal-bound water. The goal of this study was to determine if raloxifene-induced alterations in skeletal hydration could be measured in vivo using ultra-short echotime magnetic resonance imaging (UTE-MRI). Twelve skeletally mature female beagle dogs (n = 6/group) were treated for 6 months with oral doses of saline vehicle (VEH, 1 mL/kg/d) or raloxifene (RAL, 0.5 mg/kg/d). After 6 months of treatment, all animals underwent in vivo UTE-MRI of the proximal tibial cortical bone. UTE-MRI signal intensity versus echotime curves were analyzed by fitting a double exponential to determine the short and long relaxation times of water with the bone (dependent estimations of bound and free water, respectively). Raloxifene-treated animals had significantly higher bound water (+14%; p = 0.05) and lower free water (-20%) compared with vehicle-treated animals. These data provide the first evidence that drug-induced changes in skeletal hydration can be noninvasively assessed using UTE-MRI.

Pulmonary artery dissection in eight dogs with patent ductus arteriosus

ObjectivesTo describe a series of dogs with pulmonary artery dissection and patent ductus arteriosus (PDA). AnimalsEight dogs. MethodsRetrospective case series. ResultsPulmonary artery dissection was diagnosed in 8 dogs, 3 were Weimaraners. Four dogs presented in left-sided congestive heart failure, 4 presented for murmur evaluation and without clinical signs, and 1 presented in right-sided congestive heart failure. In 7 dogs the dissection was first documented concurrent with a diagnosis of uncorrected PDA. In the other dog, with pulmonary valve stenosis and PDA, the dissection was observed on autopsy examination 17 months after balloon pulmonary valvuloplasty and ductal closure. Median age at presentation for the 7 dogs with antemortem diagnosis of pulmonary artery dissection was 3.5 years (range, 1.5–4 years). Three dogs had the PDA surgically ligated, 2 dogs did not undergo PDA closure, 1 dog failed transcatheter occlusion of the PDA with subsequent surgical ligation, 1 dog underwent successful transcatheter device occlusion of the PDA, and 1 dog had the PDA closed by transcatheter coil delivery 17 months prior to the diagnosis of pulmonary artery dissection. The 2 dogs that did not have the PDA closed died 1 and 3 years after diagnosis due to heart failure. ConclusionsPulmonary artery dissection is a potential complication of PDA in dogs, the Weimaraner breed may be at increased risk, presentation is often in mature dogs, and closure of the PDA can be performed and appears to improve outcome.

Autophagy in SDF-1α-mediated DPSC migration and pulp regeneration

Critical morphological requirements for pulp regeneration are tissues replete with vascularisation, neuron formation, and dentin deposition. Autophagy was recently shown to be related to angiogenesis, neural differentiation, and osteogenesis. The present study aimed to investigate the involvement of autophagy in stromal cell-derived factor-1α (SDF-1α)-mediated dental pulp stem cell (DPSC) migration and pulp regeneration, and identify its presence during pulp revascularisation of pulpectomised dog teeth with complete apical closure. In vitro studies showed that SDF-1α enhanced DPSCs migration and optimised focal adhesion formation and stress fibre assembly, which were accompanied by autophagy. Moreover, autophagy inhibitors significantly suppressed, whereas autophagy activator substantially augmented SDF-1α-stimulated DPSCs migration. Furthermore, after ectopic transplantation of tooth fragment/silk fibroin scaffold with DPSCs into nude mice, pulp-like tissues with vascularity, well-organised fibrous matrix formation, and new dentin deposition along the dentinal wall were generated in SDF-1α-loaded samples accompanied by autophagy. More importantly, in a pulp revascularisation model in situ, SDF-1α-loaded silk fibroin scaffolds improved the de novo ingrowth of pulp-like tissues in pulpectomised mature dog teeth, which correlated with the punctuated LC3 and Atg5 expressions, indicating autophagy. Our findings provide novel insights into the pulp regeneration mechanism, and SDF-1α shows promise for future clinical application in pulp revascularisation.

Associations between early radiographic and computed tomographic measures and canine hip joint osteoarthritis at maturity.

To evaluate associations of measures assessed by radiography, 2-D CT, and 3-D CT of the hip joints of immature dogs with osteoarthritis in the same joints at maturity. 46 hound-type dogs from a colony predisposed to osteoarthritis. Images of hip joints (1/dog) were obtained at 16, 32, and 104 weeks of age. Radiographic measures included Norberg angle, distraction index, and osteoarthritis score. Two-dimensional CT measures included acetabular index, percentage of femoral head coverage, and center edge, horizontal toit externe, acetabular anteversion, and ventral, dorsal, and horizontal acetabular sector angles. Three-dimensional CT measures were femoral head and neck volume, femoral neck angle, and femoral head and neck radius. Differences among measures at 16 and 32 weeks in dogs with different osteoarthritis scores at later time points, relationships among variables at each time point, and relationships of single and combined measures with the presence of osteoarthritis at 104 weeks were evaluated. The 16- and 32-week distraction index, center edge angle, dorsal acetabular sector angle, horizontal acetabular sector angle, percentage of femoral head coverage, acetabular index, and Norberg angle and the 32-week femoral neck angle varied significantly with osteoarthritis severity at 104 weeks. Presence of osteoarthritis in mature dogs was most strongly associated with 16-week combined measures of distraction index and center edge angle and 32-week combined measures of dorsal acetabular sector angle and Norberg angle. Changes in hip joint morphology associated with radiographic signs of osteoarthritis were detectable as early as 16 weeks of age and varied with osteoarthritis severity in adult dogs. The use of combined hip joint measures may improve early identification of dogs predisposed to hip joint osteoarthritis.

Tibial Plateau Leveling Osteotomy for Treatment of Naturally Occurring Cranial Cruciate Ligament Rupture in Small Breed Dogs - Case Series

This study describes a surgical technique and evaluates the clinical outcomes in small breed dogs with cranial cruciate ligament rupture (CCLR) treated with tibial plateau leveling osteotomy (TPLO). Seven skeletally mature dogs weighing less than 15 kg underwent unilateral TPLO to stabilize the stifle joint with CCLR. Clinical evaluation was performed via visual lameness score, range of motion (ROM), and thigh girth circumference (TC). Postoperative complications were recorded. All patients reached a grade 1 score at 1 week and grade 0 at 8 weeks postoperatively. The mean operated limb extension angle was 98.11%, 99.07%, and 98.73% of the mean extension angle of the contralateral limb at 4 weeks, 8 weeks, and 12 weeks postoperatively, respectively. The mean operated limb flexion angle was 98.07%, 95.88%, and 96.35% of the mean flexion angle of the contralateral limb at 4 weeks, 8 weeks, and 12 weeks postoperatively, respectively. The mean TC of the operated limb was 92.95%, 93.68%, and 95.44% of the mean TC of the normal limb at 4 weeks, 8 weeks, and 12 weeks postoperatively, respectively. Our outcomes for TPLO in small breed dogs are not worse than those previously reported for large breed dogs. Based on the result in the present study, CCLR in small dogs can be successfully managed with TPLO, as done in large breed dogs.

Effects of ocular surface strontium-90 beta radiotherapy in dogs latently infected with canine herpesvirus-1

Latent canine herpesvirus-1 (CHV-1) infections are common in domestic dogs, but stimuli causing viral reactivation and recrudescent disease are poorly understood. Immunosuppressive pharmaceuticals are currently the only experimentally established triggers for recurrent ocular CHV-1 infection in dogs; however, ocular CHV-1 shedding has been reported clinically following strontium-90 beta radiotherapy of the ocular surface and it has been speculated that radiotherapy can directly induce viral reactivation. Strontium-90 is used as a beta radiation source for the treatment of a variety of neoplastic and immune-mediated canine ocular surface diseases. In the present study, the effects of ocular surface strontium-90 beta radiotherapy in dogs latently infected with CHV-1 were evaluated. Ten mature dogs with experimentally induced latent CHV-1 infections were randomly divided into two groups: one group received a single fraction 50Gy radiation dose in one application from a strontium-90 ophthalmic applicator and the second group received sham radiotherapy. Dogs were then monitored for 45 days for recurrent ocular CHV-1 infection using clinical and virological outcome measures. Clinical ophthalmic examinations, ocular sample CHV-1 PCR assays, and serum CHV-1 virus neutralizing antibody assays were performed at specified intervals. No abnormalities suggestive of recurrent CHV-1 ocular disease were observed on clinical examination in any dog during the study. Ocular viral shedding was not detected and CHV-1 virus neutralizing titers remained stable in all dogs. A single fraction 50Gy radiation dose administered to the ocular surface by strontium-90 beta radiotherapy did not result in detectable recurrent ocular CHV-1 infection in mature dogs with experimentally induced latent infection.

Effects of pilot holes on longitudinal miniscrew stability and bony adaptation

The purposes of this study were to longitudinally evaluate the effects of pilot holes on miniscrew implant (MSI) stability and to determine whether the effects can be attributed to the quality or the quantity of bone surrounding the MSI. Using a randomized split-mouth design in 6 skeletally mature female foxhound-mix dogs, 17 MSIs (1.6mm outer diameter) placed with pilot holes (1.1mm) were compared with 17 identical MSIs placed without pilot holes. Implant stability quotient measurements of MSI stability were taken weekly for 7weeks. Using microcomputed tomography with an isotropic resolution of 6μm, bone volume fractions were measured for 3 layers of bone (6-24, 24-42, and 42-60μm) surrounding the MSIs. At placement, the MSIs with pilot holes showed significantly (P<0.05) higher implant stability quotient values than did the MSIs placed without pilot holes (48.3 vs 47.5). Over time, the implant stability quotient values decreased significantly more for the MSIs placed with pilot holes than for those placed without pilot holes. After 7weeks, the most coronal aspect of the 6- to 24-μm layer of cortical bone and the most coronal aspects of all 3 layers of trabecular bone showed significantly larger bone volume fractions for the MSIs placed without pilot holes than for those placed with pilot holes. MSIs placed with pilot holes show greater primary stability, but greater decreases in stability over time, due primarily to having less trabecular bone surrounding them.

Differential expression of microRNAs in sexually immature and mature canine testes

Mammalian testis exhibits spatiotemporal gene expression patterns that are essential for successful and continuous spermatogenesis. Although microRNAs (miRNAs) modify gene expression through translational repression and degradation of target messenger RNAs, the precise molecular mechanisms of these regulatory processes are unclear. We used canine miScript miRNA polymerase chain reaction (PCR) Array technology to elucidate the repertoire of canine testis miRNAs and compared their expression patterns between sexually immature (prepubertal) and mature (adult) dog testes. Eighty-four well-characterized canine miRNAs were customized in this study. The data were analyzed by RT2 Profiler PCR Array Data Analysis (version 3.5). Results identified upregulation of 32 and considerable downregulation of 12 miRNAs in adult dog testis. In conclusion, the two developmental stages had significantly different miRNAs expression patterns. The finding provides fundamental information of miRNAs which may help to elucidate their role in spermatogenesis and male infertility in this species. To the best of our knowledge, this study is the first to offer comparative profile of the miRNA transcriptome in prepubertal and adult canine testes using miRNA PCR array approach.