Adult Canines Research Articles

Variabilidad de la frecuencia cardiaca en caninos saludables, adultos, y residentes en hipoxia hipobárica (Bogotá, 2600 metros sobre el nivel del mar)

Heart rate variability (HRV) refers to beat-to-beat fluctuations in heart rate and represents the neurovegetative and endocrine influence on the heart. In the present study, HRV values were obtained in healthy adult canines of both sexes, residing in the city of Bogotá (2600 meters above sea level). Time-domain and frequency-domain HRV parameters were obtained using 60-minute Holter recordings. The distribution of the data was determined using the Shapiro-Wilk test. The dogs were distributed into two subgroups to study their behaviour in relation to sex and age. ANOVA and Kruskal Wallis tests were used to determine statistical differences. In general, the mean HRV values differ from those reported by other authors in studies at sea level and at lower altitudes. The differences in HRV in relation to sex were significant in the RMSSD and pNN50 parameters. There were no differences in the relationship between HRV and age.

Comparing the effects of various fluid resuscitative strategies on Glycocalyx damage in a canine hemorrhage model

Hemorrhagic shock and subsequent resuscitation can cause significant dysregulation of critical systems, including the vascular endothelium. Following hemorrhage, the endothelial lining (glycocalyx) can shed, causing release of glycocalyx components, endothelial activation, and systemic inflammation. A canine model of hemorrhagic shock was used to evaluate five resuscitation fluids, including Lactated Ringers+Hetastarch, Whole Blood (WB), Fresh Frozen Plasma+packed Red Blood Cells (FFP+pRBC), and two hemoglobin-based oxygen carrier (HBOC) fluids, for their impact on glycocalyx shedding. Under anesthesia, purpose-bred adult canines were instrumented and subjected to a controlled hemorrhage with blood being drawn until a mean arterial pressure of <50 mmHg was reached or 40 % of the estimated blood volume was removed. Canines were left in shock for 45 mins before being resuscitated with one of the resuscitation fluids over 30 mins. Following resuscitation, the dogs were monitored up to 2 weeks. Following an additional 3–4 weeks for washout, the canines repeated the protocol, undergoing each resuscitation fluid individually. Blood samples were collected during each round at various timepoints for serum isolation, which was used for detection of glycocalyx biomarker. Comparison of baseline and post-hemorrhage alone showed a significant reduction in serum protein (p<0.0001), heparan sulfate (p<0.001), and syndecan-1 (p<0.0001) concentrations, and a significant increase in hyaluronan (p<0.0001) concentration. Intercomparisons of resuscitation fluids indicated minimal differences in glycocalyx markers over time. Comparisons within each fluid showed dynamic responses in glycocalyx biomarkers over time. Relative to individual baselines, syndecan-1 was significantly reduced after resuscitation in most cases (p<0.0001), excluding WB and FFP+pRBC. In all cases, VE-cadherin was significantly elevated at 24 hr compared to baseline (p<0.001). Hyaluronan was significantly elevated by 3 hr in all cases (p<0.01), except for HBOC fluids. Total glycosaminoglycans were significantly reduced only at 3 hr (p<0.001) for non-HBOC fluids. Similarly, heparan sulfate was significantly reduced with all fluids between resuscitation and 24 hr (p<0.01), except WB. The temporal changes in canine glycocalyx biomarkers were atypical of hemorrhage response in other species. This suggests that the hemorrhage lacked severity and/or typical glycocalyx biomarkers do not reflect the canine endothelium compared to other species. Further research is needed to characterize the canine endothelium and the response to resuscitation fluids.

Post-surgical complications in canine patients with cranial cruciate ligament rupture

Cranial Cruciate Ligament Rupture (CrCL) is one of the most common orthopaedic pathologies in canines. The objective of this study was to report the complications that occur in canine patients with CrCL treated with an extra-articular stabilization technique. The age, breed and weight of the dogs and their possible relationship with any post-surgical complications were considered. Surgical procedures were based on the description of Flo (1975). Complications were classified as catastrophic, moderate and mild. Clinical data of 80 canines were used, where 7 (8.75%) presented postsurgical complications, 5 presented moderate complications (71.4%) and 2 patients presented mild complications (28.6%), while 73 (91.25%) of patients did not present complications in their recovery. The presentation of CrCL was significantly higher (p&lt;0.001) in adult canines and in patients with a body weight greater than 15 kg (p&lt;0.001).

Bending performance changes during prolonged canine eruption in saber-toothed carnivores: A case study of Smilodon fatalis.

The canine of saber-toothed predators represents one of the most specialized dental structures known. Hypotheses about the function of hypertrophied canines range from display and conspecific interaction, soft food processing, to active prey acquisition. Recent research on the ontogenetic timing of skull traits indicates the adult canine can take years to fully erupt, but the consequences of prolonged eruption on inferences of canine functional morphology are missing from current discourse and have not been quantified. Here I evaluate hypotheses about adult canine bending strength and stiffness, respectively, during eruption in the felid Smilodon fatalis. Simulated eruption sequences of three adult canines were generated from specimen models to assess shifting cross-sectional geometry properties, and bending strength and stiffness under laterally directed loads were estimated using finite element analysis. Consistent with beam theory expectations, S. fatalis canine cross-sectional geometry is optimized for increased bending strength with increased erupted height. However, canine cross-sectional geometry changes through eruption exaggerate rather than minimize lateral deflection. Spatial constraint for maximum root length from adjacent sensory structures in the maxilla and the recently identified universal power law are hypothesized to limit the growth capacity of canine anteroposterior length and, consequently, maintenance of bending stiffness through eruption. Instead, the joint presence of the deciduous and adult canines for >50% of the adult canine eruption period effectively increases canine mediolateral width and brings bending strength and stiffness estimates closer to theoretical optima. Similarly prolonged retention of deciduous canines in other sabertooths suggests dual-canine buttressing is a convergently evolved strategy to maximize bending strength and stiffness.

Abstract 19064: Sex Specific Gene Profile in Canine Sinoatrial Node

Introduction: Biological sex plays an important role in cardiac function and occurrence of cardiac arrhythmias. Clinical reports show that adult females have faster resting and intrinsic heart rate (HR) while males have faster HR peak and larger HR reserve. Furthermore, inappropriate sinus tachycardia primarily occurs in females, suggesting sex-specific function and/or structure of the sinoatrial node (SAN). The aim of the study is to define sex-specific molecular features of the SAN complex. Methods: mRNA was isolated from SAN pacemaker tissue of healthy adult canines (male=4, female=4). Differential RNA expression patterns of &gt;400 genes, including fibrosis, inflammation, and metabolism markers were quantified with nCounter Nanostring fibrosis panel. Quantitative PCR was used to compare mRNAs of key ion channels related to SAN pacemaker function. Results: Nanostring panel revealed sex-specific and SAN-specific gene profiles of inflammation and fibrotic markers with multiple mRNAs higher in male (e.g. NLRP3, CD86, COL3A1, TGFB1) and several higher in females (e.g. MARCOL, IL20RB). mRNAs responsible for SAN pacemaking e.g. HCN1, HCN4, Cav1.3, and GIRK4 are higher expressed in female SAN. Sex-specific retrospective analysis of published gene profiles from non-failing human hearts showed a similar pattern to canine with HCN1, HCN4, Cav1.3 expression higher in female SAN. Conclusions: The study revealed significantly different gene expressions of fibrosis, inflammation, and pacemaking in male vs female SAN. The higher expression of HCN1/4 and Cav1.3 may explain the faster intrinsic sinus rhythm and susceptibility to SAN arrhythmias in females. The elevated fibrosis and inflammation genes in male SAN may suggest higher vulnerability to fibrotic remodeling during cardiac disease.

Impact of a Static Magnetic Field on Early Osseointegration: A Pilot Study in Canines.

A static magnetic field generated by neodymium-iron-boron (NdFeB) magnets placed in the inner cavity of dental implants can enhance bone regeneration in rabbits. It is, however, unknown whether static magnetic fields support osseointegration in a canine model. We therefore determined the potential osteogenic effect of implants carrying NdFeB magnets inserted in the tibia of six adult canines in the early stages of osseointegration. Here, we report that after 15 days of healing, magnetic and regular implants showed a high variation with a median new bone-to-implant contact (nBIC) in the cortical (41.3% and 7.3%) and the medullary (28.6% and 44.8%) region, respectively. Consistently, the median new bone volume/tissue volume (nBV/TV) in the cortical (14.9% and 5.4%) and the medullary (22.2% and 22.4%) region were not significantly different. One week of healing only resulted in negligible bone formation. These findings suggest that considering the large variation and the pilot nature of this study, magnetic implants failed to support peri-implant bone formation in a canine model.

Comparative plasma and urine metabolomics analysis of juvenile and adult canines.

The metabolomic profile of a biofluid can be affected by age, and thus provides detailed information about the metabolic alterations in biological processes and reflects the in trinsic rule regulating the growth and developmental processes. To systemically investigate the characteristics of multiple metabolic profiles associated with canine growth, we analyzed the metabolomics in the plasma and urine samples from 15 young and 15 adult beagle dogs via UHPLC-Q-TOFMS-based metabolomics. Blood routine and serum biochemical analyses were also performed on fasting blood samples. The metabolomics results showed remarkable differences in metabolite fingerprints both in plasma and urine between the young and adult groups. The most obvious age-related metabolite alterations include decreased serumlevels of oxoglutaric acid and essential amino acids and derivatives but increased levels of urine levels of O-acetylserine. These changes primarily involved in amino acid metabolism and bile secretion pathways. We also found that the levels of glutamine were consistently higher in both serum and urine of adults, while N-acetylhistamine and uracil concentrations were much lower in the adult group compared to younger ones. Our study provides a whole metabolic profile of serum and urine characteristics of young and adult canines, identifying several metabolites that were significantly associated with age change, which provides theoretical support for the nutrition-related research and age-related homeostasis maintenance in dogs.

The impact of protein source and grain inclusion on digestibility, fecal metabolites, and fecal microbiome in adult canines.

This study was conducted to determine the effect of animal protein inclusion rate and grain-free or grain-inclusive diets on macronutrient digestibility, fecal characteristics, metabolites, and microbiota in mixed-breed hounds and Beagles. Four experimental extruded kibble diets were made with varying amounts of animal protein and carbohydrates: 1) high animal protein, grain-inclusive (HA-GI), 2) low animal protein, grain-free (LA-GF), 3) low animal protein, grain-inclusive (LA-GI), and 4) high animal protein, grain-free (HA-GF). Thirty-two Beagles and 33 mixed-breed hounds were assigned to 1 of the 4 treatment groups in a completely randomized design that lasted 180 d. All diets were similar in chemical composition and well-digested by the animals. In general, for fecal metabolites, mixed-breed hounds had a greater concentration of total short-chain fatty acid (SCFA) and ammonia and lower indole concentration than Beagles (P < 0.05). In mixed-breed hounds, LA-GF had a greater (P < 0.05) total SCFA concentration than HA-GI and LA-GI; however, this was not observed in Beagles. There were greater concentrations of ammonia, phenol, and indole in HA-GI than in LA-GF (P < 0.05). Breed-affected fecal primary bile acid (BA) concentration, as mixed-breed hounds had a greater concentration of cholic acid (CA) than Beagles (P < 0.05). Mixed-breed hounds fed LA-GF resulted in greater CA concentrations than HA-GI and LA-GI (P < 0.05). Dogs who consumed LA-GF had lower fecal secondary BA content than the other groups (P < 0.05). The distribution of the fecal microbiota community differed in LA-GF compared with the other groups, with lower α-diversity. However, dogs fed LA-GF had the largest difference in composition with greater Selenomonadaceae, Veillonellaceae, Lactobacillaceae, Streptococcus, Ligilactobacillus, Megamonas, Collinsella aerofaciens, and Bifidobacterium sp. than the other groups. A significant breed effect was noted on nutrient digestibility, fecal metabolites, and microbiota. A treatment effect was observed in LA-GF as it resulted in greater fecal SCFA, lower protein fermentative end products, greater fecal primary BAs, lower fecal secondary BA concentrations, and shifts in fecal microbiota.

The Clinical Guiding Role of the Distribution of Corneal Nerves in the Selection of Incision for Penetrating Corneal Surgery in Canines.

The cornea is one of the regions with the highest density of nerve terminals in the animal body and it bears such functions as nourishing the cornea and maintaining corneal sensation. In veterinary clinical practice, the corneoscleral limbus incision is frequently applied in cataract surgery, peripheral iridectomy, and other procedures for glaucoma. Inevitably, it would cause damage to the nerve roots that enter the cornea from the corneal limbus, thus inducing a series of complications. In this paper, the in vitro cornea (39 corneas from 23 canines, with ages ranging from 8 months old to 3 years old, including 12 male canines and 11 female canines) was divided into 6 zones, and the whole cornea was stained with gold chloride. After staining, corneal nerves formed neural networks at different levels of cornea. There was no significant difference in the number of nerve roots at the corneoscleral limbus between different zones (F = 1.983, p = 0.082), and the nerve roots at the corneoscleral limbus (mean value, 24.43; 95% CI, 23.43–25.42) were evenly distributed. Additionally, there was no significant difference in the number of corneal nerve roots between male and female canines (p = 0.143). There was also no significant difference in the number of corneal nerve roots between adult canines and puppies (p = 0.324). The results of the above analysis will provide a reasonable anatomical basis for selecting the incision location and orientation of penetrating surgery for the canine cornea in veterinary practice.

Abstract 10593: Computationally Modeling Cardiac Growth and Hemodynamics in Healthy Infants

Introduction: Previous computer models have been developed which predict cardiac growth and remodeling in adults with various pathologies, including hypertension, valvular disease, and myocardial infarction. Applying these models to infants and children is complicated by the fact that they also undergo normal, somatic cardiac growth and remodeling. Objective: Create a computational model to predict ventricular dimensions and hemodynamics in healthy, growing infants. Methods: A left ventricular growth model previously published by our lab for adult canines was modified for healthy infants. The four heart chambers were modeled as time-varying elastances coupled to a circuit model of the circulation. Circulation parameters were allometrically scaled for human infants. Early trends in systemic and pulmonary vascular resistance were fit to clinical data rather than scaled due to the dramatic reduction in pulmonary vascular resistance and marked increase in overall systemic vascular resistance immediately post-birth. Ventricular growth was driven by perturbations in myocyte strain, a non-dimensional metric. Reported heart rate was input directly into the model. Results: The model successfully matched clinically measured values of systemic and pulmonary pressures, end-systolic and end-diastolic left and right ventricular volumes, maximum atrial volumes, and left ventricular end-diastolic thickness within one standard deviation of multiple studies for children aged 0-3 years (Figure). LV end-systolic and right ventricular end-diastolic thicknesses followed clinical trends but were outside of established ranges. Conclusions: Our model predicts hemodynamics and ventricular dimensions for healthy children from birth to 3 years. From this, we can gain a greater understanding of the interplay between somatic and pathological growth in infants and children with congenital heart defects.

The Application and Teaching Value of a Ventricular Septal Defect Canine Model Established by Transcatheter Puncture.

This study aimed to improve and further explore a ventricular septal defect (VSD) canine model on the basis of the transcatheter puncture method and to evaluate its application and teaching value.In order to lessen the complications of VSD closure, it is necessary to improve the currently available treatment devices using appropriate animal models.In this study, we used 16 healthy adult canines as our models. After anesthesia, the VSD puncture was performed, followed by balloon dilatation of the perforation. VSD was confirmed by angiography. The venous-artery orbit was established, and the VSD was then closed once the catheter and occluder were across the defect.Of the experimental canines, 14 of the 16 canines were successfully modeled, giving a success rate of 87.5%. The canines underwent an immediate creation of a venous-artery orbit for teaching practice and were implanted with an occluder during the procedure. After 4 weeks, 13 canines survived. As per our findings, most VSD types established by the puncture were perimembranous (10 of 13, 77%).The current model has a high success rate. The model can not only avoid the risk of infection and hemodynamic disorders associated with an open thoracotomy, but can also be effectively used in evaluating the impact of occluders. It can also directly measure the parameters of the devices during the procedure, thus having a very high experimental and teaching value.

Effect of CRRT combined with low-flow ECMO on canines with ARDS and hypercapnia.

To observe the effect of continuous renal replacement therapy (CRRT) combined with low-flow extracorporeal membrane oxygenation (ECMO) of V-V mode on anti-inflammation, improving oxygenation and reducing PaCO2 in canines with acute respiratory distress syndrome (ARDS) and hypercapnia. A total of 30 healthy adult canines were randomly divided into sham group (n = 10), ECMO (EC) group (n = 10) and CRRT + ECMO (CR + EC) group (n = 10). Sham group was only treated with invasive mechanical ventilation. EC group was also treated with ECMO. CR + EC group was treated with CRRT combined with low-flow ECMO of V-V mode besides invasive mechanical ventilation. The results showed that hazard ratio was lower in the CR + EC group. Inflammatory factors, OI values, and PaCO2 levels were lower in the CR + EC group. There was no significant difference in the levels of MAP, CO and T among the three groups. No significant complications or death was developed in the three groups. Compared with ECMO group at T3, T6 and T9, IL-6 [(276.13 ± 8.32, 262.04 ± 7.15, 259.33 ± 7.31)ng/L VS (352.67 ± 19.24, 360.24 ± 23.58, 362.21 ± 25.24)ng/L] and TNF-α [(50.14 ± 1.75, 50.45 ± 1.81, 48.03 ± 1.24) ng/L VS (70.25 ± 3.02, 72.45 ± 3.25, 76.69 ± 2.18)ng/L] in CR + EC group were decreased (P < 0.0001). Compared with sham group, IL-6 [(343.76 ± 21.97, 345.91 ± 19.89, 340.34 ± 22.17)ng/L]and TNF-α [(68.10 ± 2.96, 67.31 ± 3.01, 70.34 ± 3.35)ng/L] of T3, T6 and T9 in CR + EC group were lower (P < 0.0001). These findings indicated that CRRT combined with low-flow ECMO of V-V mode had a positive effect on anti-inflammation, oxygenation improvement and surplus blood CO2 removal in canines with ARDS and hypercapnia. These results provide a promising treatment regimen for ARDS.

80 Effects of miscanthus fiber on nutrient digestibility and fecal metabolites of adult dogs

Abstract Dietary fiber is an important component of pet food that helps to promote colonocyte health by favoring saccharolytic fermentation and short-chain fatty acid production in addition to modulating gut microbiota and aiding laxation. The objective of this study was to evaluate and compare the effects of miscanthus grass fiber, prebiotic fiber blends, and traditional dietary fiber sources on apparent total tract digestibility, fecal metabolites, and gastrointestinal intolerance in adult canines. Animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee. Twelve female adult beagles were randomly assigned to one of six treatments containing cellulose, beet pulp, miscanthus fiber, or a blend of miscanthus fiber and tomato pomace, miscanthus fiber and resistant starch, or miscanthus fiber and fructooligosaccharide in a replicated 6x6 Latin square design. All treatment diets were formulated to meet or exceed AAFCO nutrient profile (2018). The dogs received each treatment for 21 d, with 17 d of diet adaptation followed by 4 d of total and fresh fecal collection. No difference in fecal score was observed (P &amp;lt; 0.05). Dogs fed the beet pulp diet had the highest organic matter digestibility and total dietary fiber digestibility (P &amp;lt; 0.05) when compared to all other treatments. Crude protein digestibility was significantly higher (P &amp;lt; 0.05) for the cellulose, miscanthus fiber, and miscanthus and resistant starch blend than the beet pulp diet. Fecal total short-chain fatty acid concentration was greatest for beet pulp and lowest for the cellulose treatment (P &amp;lt; 0.05) with the miscanthus fiber and miscanthus fiber blends with resistant starch, fructooligosaccharide, and tomato pomace being intermediate. No difference was observed in fecal total branched-chain fatty acid concentration (P &amp;lt; 0.05). The data suggest that miscanthus fiber is an adequate and functional source of fiber in extruded canine diets, and comparable to the traditional fiber source, cellulose.

Criopreservación de semen canino (Canis familiaris) en pajilla francesa en el municipio de Medellín, Antioquia

El objetivo de este trabajo fue aplicar la metodología de criopreservación de semen canino en pajilla francesa en el municipio de Medellín- Antioquia. Se realizó una colecta seminal a ocho caninos adultos, por método de mano enguantada, cada eyaculado fue evaluado macroscópica y microscópicamente y posteriormente diluido con Triladyl® a una concentración final de 80 x 106 espermatozoides/ml. Se empacaron en pajillas de 0,5 ml y fueron sometidas a criopreservación con un descenso de temperatura rápido, sometiendo las pajillas a vapores de nitrógeno durante 25 minutos y luego transferidas directamente a nitrógeno líquido (método de pajilla francesa). En el semen fresco, se observó una apariencia blanquecina lechosa, un volumen de 2.27 ml (±1.40) una concentración de 388.5 x106 espermatozoides/ mL (±228.069), una motilidad individual de 79% (± 4%) y un vigor de 3.96 (±0.327). Se obtuvieron 123 pajillas, de las cuales se tomaron 27 aleatoriamente y se les evaluó la motilidad individual (51 ± 19%) y vigor (2.89 ± 1.02). En conclusión, la aplicación de la metodología de criopreservación rápida por pajilla francesa, usando Triladyl® como crioprotector, se sugiere como protocolo eficiente para la criopreservación de semen canino en el municipio de Medellín.

Inter-premolar width changes related to the orthodontic traction of maxillary impacted canines in adolescents and young adults: A retrospective CBCT study

Maxillary canine impaction is directly associated with a narrow maxillary arch, mainly in the inter-premolar widths. This study compared the transverse changes at the level of maxillary premolars after traction of maxillary impacted canines (MICs) in adolescents and young adults through three main goals: to compare unilateral versus bilateral cases, to compare buccally versus palatally MIC cases, and to compare the affected versus non-affected side exclusively in the unilateral group. This before and after CBCT study involved 45 MIC orthodontically tractioned until the occlusal plane with a standardized protocol. The sample was classified regarding the impaction type (unilateral versus bilateral), impaction location (palatal versus buccal) and the affected versus unaffected sides in the unilateral cases. MIC characteristics as impaction sector, height, and complexity of the traction, as well as α and β angles, canine root length and area were measured. Moreover, cephalometric characteristics were also evaluated. Mann-Whitney U or Wilcoxon signed-rank tests and multiple regressions were applied (α=0.05). Maxillary inter-premolar widths (first or second) expanded approximately 3mm after traction of unilateral or bilateral MIC (P>0.05). Changes in hemi-arch widths between palatal (1.67mm) versus buccal (1.90mm) MIC were similar (P>0.05). In unilateral impaction, the transversal changes on the affected side were 2mm versus almost 1mm observed in the unaffected side (P<0.05). Finally, the multiple linear regressions were identified to the ANB angle, the impaction sectors and the distance from middle raphe to the cusp tip of MIC as influential variables. The maxillary inter-premolar widths increase after traction of MIC without differences between type or location of impaction. In addition, the transverse change in the affected side in unilateral MIC is greater than the unaffected side resolving the earlier transverse asymmetry.

Traction of an impacted maxillary canine with corticotomy in a 53-year-old patient: Case report

The viability of orthodontic traction of impacted teeth in adults is often questioned by a large percentage of orthodontists who would rather consider the extraction of these teeth. Although possible, orthodontic traction of impacted canines in adults takes longer than in younger patients, present a poorer prognosis that worsens with age. Because of the prevalence of periodontitis in adults versus children, periodontal inflammation must be identified and resolved in order to keep attachment loss from progressing during orthodontic care. Likewise mucogingival changes need to be predicted and managed. This article reports a successful case of impacted maxillary right canine traction in an adult female, associated with alveolar corticotomies and the use of skeletal anchorage. At the end of treatment, the canine was ideally positioned in the occlusion, presenting excellent esthetics, function, and healthy periodontal tissues.

Erythropoietin inhalation enhances adult canine alveolar-capillary formation following pneumonectomy.

Paracrine erythropoietin (EPO) signaling in the lung recruits endothelial progenitor cells, promotes cell maturation and angiogenesis, and is upregulated during canine postpneumonectomy (PNX) compensatory lung growth. To determine whether inhalational delivery of exogenous EPO augments endogenous post-PNX lung growth, adult canines underwent right PNX and received, via a permanent tracheal stoma, weekly nebulization of recombinant human EPO-containing nanoparticles or empty nanoparticles (control) for 16 wk. Lung function was assessed under anesthesia pre- and post-PNX. The remaining lobes were fixed for detailed morphometric analysis. Compared with control treatment, EPO delivery significantly increased serum EPO concentration without altering systemic hematocrit or hemoglobin concentration and abrogated post-PNX lipid oxidative stress damage. EPO delivery modestly increased post-PNX volume densities of the alveolar septum per unit of lung volume and type II epithelium and endothelium per unit of septal tissue volume in selected lobes. EPO delivery also augmented the post-PNX increase in alveolar double-capillary profiles, a marker of intussusceptive capillary formation, in all remaining lobes. EPO treatment did not significantly alter absolute resting lung volumes, lung and membrane diffusing capacities, alveolar-capillary blood volume, pulmonary blood flow, lung compliance, or extravascular alveolar tissue volumes or surface areas. Results established the feasibility of chronic inhalational delivery of growth-modifying biologics in a large animal model. Exogenous EPO selectively enhanced cytoprotection and alveolar angiogenesis in remaining lobes but not whole-lung extravascular tissue growth or resting function; the nonuniform response contributes to structure-function discrepancy, a major challenge for interventions aimed at amplifying the innate potential for compensatory lung growth.

Safety and efficacy of stereotactic radioablation targeting pulmonary vein tissues in an experimental model

Stereotactic radioablation (SR), a commonly used therapy to treat malignant tumors, has been used to treat refractory ventricular tachycardia, but the feasibility of treating atrial fibrillation with SR is unknown. We evaluated the safety and efficacy of SR targeting pulmonary vein (PV) antral tissues as a potential therapy for atrial fibrillation. Seventeen adult canines and 2 adult swine underwent surgical fiducial marker placement, 3-dimensional anatomic rendering computed tomography angiogram of the left atrium, and creation of a treatment plan targeting the right superior PVs. Four treatment doses (15, 20, 25, and 35 Gy) were administered to 4 cohorts. Subjects were monitored for 3-6 months, followed by electrophysiological testing, gross pathological examination, and histopathology in 2 subjects. All subjects received SR treatment without complication. Electrophysiology study and gross pathological analysis demonstrated treatment effect in all treated PVs at 35 Gy and 25 Gy (n= 11 of 11 [100%]), with a partial effect at 20 Gy (n = 4 of 5 [80%]; 1 did not undergo repeat electrophysiology study) and 15 Gy (n = 1 of 2 [50%]). No evidence of collateral injury was found in tissues directly adjacent to the treated PVs. In 2 subjects, detailed histopathology demonstrated evidence of circumferential, transmural scar at the PV ablation sites, with sparing of the surrounding structures. SR is safe and effective for creating precise circumferential scar and electrical isolation of the right superior PV in an experimental model, with dose dependence between delivered radioablative energy and observed electrical effects.

WITHDRAWN: Beneficial effect of endo-CRT might be mediated by more improvement of SERCA2A in chronic dyssynchronous canine heart failure models

// Hongyun Chen 1 , Shuang Liu 2 , Zhihong Zong 3 , Cuiting Zhao 2 , Guangyuan Li 2 , Yonghuai Wang 2 , Guoxian Qi 1 , Jun Yang 2 and Chunyan Ma 2 1 Department of Geriatric Cardiology, First Hospital of China Medical University, Shenyang, Liaoning, China 2 Department of Cardiovascular Ultrasound, First Hospital of China Medical University, Shenyang, Liaoning, China 3 China Medical University, Shenyang, Liaoning, China Correspondence to: Chunyan Ma, email: cmu1h_mcy@126.com Keywords: cardiac resynchronization therapy (CRT); SERCA2A; endo-CRT; epi-CRT; dyssynchronous heart failure Received: March 29, 2017 Accepted: December 29, 2017 Published: January 02, 2018 ABSTRACT The aims of the present study were to compare the effects of endocardial cardiac resynchronization therapy (endo-CRT) and epicardial CRT (epi-CRT) on cardiac contractile function and to delineate the underlying molecular mechanisms. Twenty-four adult mongrel canines were divided into four groups: sham-operation control group (CT, n = 6), dyssynchronous heart failure (DHF) group ( n = 6), epi-CRT group ( n = 6), and endo-CRT group ( n = 6). The global and local left ventricle (LV) systolic function, dyssynchrony and myocardium calcium handling molecular mRNA and protein levels were measured. Compared to CT group, we found the global and local LV function, dyssynchrony and SERCA2A decreased in DHF group and increased in CRT groups, particularly in endo-CRT group at LV lateral wall (pacing site). Therefore, endo-CRT appears to be an effective procedure in the treatment of DHF, which might be mediated by upregulating the mRNA and protein expression of SERCA2A in the LV at the pacing and remote site.

Clinical Outcome of an Impacted Maxillary Canine: From Exposition to Occlusion

The aim is to report a case of impacted maxillary right canine successfully positioned into the occlusion line. Although the treatment of choice for an impacted canine is a combined surgical-orthodontic approach, there are differences in technique. The preorthodontic uncovering and autonomous eruption technique is a safe and predictable option for the treatment of palatally impacted maxillary canines in adolescents and adults as is the orthodontic creation of a space before minimal surgical exposure, the bonding of a small attachment (an eyelet), full-flap closure, and immediate traction. Although the mechanical management of impacted teeth is a routine task for most orthodontists, certain types of impaction can be frustrating. An 18-year-old adult patient presented for clinical examination with a mobile maxillary right deciduous canine, the absence of a maxillary right permanent canine, Angle Class I malocclusion, an overjet of 2.0 mm, an overbite of 3.0 mm, and rotated canine and left maxillary central and lateral incisors. Cephalometric measurements revealed a skeletal Class I relationship as well as upright maxillary incisors (1. NA = 18°) and mandibular incisors (1. NB = 16°, IMPA = 80°). The facial profile was concave. Clinically, a constricted maxillary arch was observed, and the patient had a nail-biting habit. The canine was aligned, leveled and positioned in the occlusion line. The esthetic, functional and periodontal results remained stable in the retention phase. Various treatment strategies are available to treat impacted maxillary canines. The surgical, periodontal, and orthodontic considerations in the management of impacted canines must be clearly explained to the patient.