In this study, histomorphometrical parameters of the peri-implant bone remodeling around degrading open-porous scaffolds made of magnesium alloy AZ91D were investigated and compared with the peri-implant bone remodeling around an autologous bone transplant in the contralateral side in a rabbit model after 3 and 6 months. Osteoblast activity was displayed by collagen I (alpha 2) mRNA in situ hybridization. Major scaffold degradation was completed within 3 months after implantation showing no osteolysis around the scaffolds, both after 3 and 6 months. Enhanced formation of unmineralized extracellular matrix and an enhanced mineral apposition rate adjacent to the degrading magnesium scaffolds were accompanied by an increased osteoclastic bone surface, which resulted in higher bone mass and a tendency to a more mature trabecular bone structure around the magnesium scaffolds compared to the control. These results show that even fast-degrading magnesium scaffolds induce extended peri-implant bone remodeling with a good biocompatibility. In summary, this study shows that degrading magnesium scaffolds promote both bone formation and resorption in a rabbit model and are therefore very promising candidates for the development of novel implants in musculoskeletal surgery.

Background: Acute kidney injury (AKI) is a common and often fatal disorder in dogs. Hypothesis: Urine neutrophil gelatinase-associated lipocalin (NGAL)/creatinine ratio is a sensitive and specific biomarker of AKI in dogs.Animals: Ninety-four dogs. Methods: Prospective study. Dogs were classified as follows: (1) healthy dogs, (2) dogs with lower urinary tract disorders, (3) dogs with chronic kidney disease (CKD), (4) dogs with azotemic International Renal Interest Society (IRIS) AKI Grades II-V, and (5) dogs with IRIS AKI Grade I (nonazotemic). Urinary NGAL was quantitated in each dog using an ELISA assay and concentrations were expressed as a ratio to urinary creatinine concentration from the same specimen, and designated the urinary NGAL/creatinine ratio (UNCR).Results: There was a significant difference in UNCR among the study groups (P < .001). Both the azotemic and nonazotemic AKI groups had higher UNCR when compared with all other groups (P < .001 for all pairs). There was a statistically significant difference in UNCR between dogs diagnosed with CKD compared with dogs with lower urinary tract diseases (P = .005) as well as between dogs with CKD and healthy dogs (P = .001). Receiver operator characteristics (ROC) analysis of UNCR as an indicator of azotemic and nonazotemic AKI had an area under the ROC curve of 0.94 and 0.96, respectively.Conclusions and Clinical Relevance: NGAL/creatinine ratio is a sensitive and specific marker of AKI. It can be used to screen patients at risk for AKI and can be utilized to diagnose milder forms of AKI potentially earlier in the course of the disease.

BackgroundUreteral stent and subcutaneous ureteral bypass (SUB) placement are commonly used for managing ureteral obstructions. Urinary tract infection (UTI) is a recognized complication.ObjectivesTo determine postoperative incidence of positive urine cultures in cats undergoing ureteral stent and SUB placement and to identify risk factors associated with positive urine cultures.DesignRetrospective study.AnimalsForty‐three cats that underwent 48 surgical events.ProceduresMedical records were reviewed. Cats were included if urine cultures were performed before and after surgery. Variables were compared to identify risk factors.ResultsUrine cultures were positive postoperatively pre‐discharge in 5/20 (25%) cats. Median duration of follow‐up post‐discharge was 209 days (range, 11‐2184 days), with a total of 143 urine cultures performed in cats post‐discharge. Of these, 16 (11%) were positive in 12/48 (25%) cats. Nine different bacteria were identified; Enterococcus spp. (n = 8) predominated as monomicrobic or mixed infections. In 14/16 instances of positive urine cultures, affected cats had lower urinary tract signs, signs of pyelonephritis or both. Cats that received antibiotics postoperatively were significantly less likely to have a positive urine culture compared to those that did not (odds ratio, 0.2, 95% confidence interval, 0.05, 0.8, P = 0.02). Chronic kidney disease, renal implant type and postoperative urinary catheterization were not associated with positive urine cultures.Conclusions and Clinical RelevancePostoperatively, occurrence of positive urine cultures was similar to previous reports. Subclinical bacteriuria was less common than UTI. Postoperative urinary catheterization has been speculated to increase risk of bacteriuria, but this was not the case in this cohort.

OBJECTIVE To evaluate the outcome for cats with benign ureteral obstructions treated by means of ureteral stenting and to compare the outcome for these cats with outcome for a historical cohort of cats treated by means of ureterotomy only. DESIGN Prospective study with historical cohort. ANIMALS 62 client-owned cats with benign ureteral obstructions, including 26 cats treated with ureteral stenting and 36 cats previously treated with ureterotomy. PROCEDURES Data were recorded prospectively (ureteral stent cases) or collected retrospectively from the medical records (ureterotomy cases), and results were compared. RESULTS Cats treated with ureteral stents had significantly greater decreases in BUN and serum creatinine concentrations 1 day after surgery and at hospital discharge, compared with values for cats that underwent ureterotomy. Six cats in the ureteral stent group developed abdominal effusion after surgery, and cats in this group were significantly more likely to develop abdominal effusion when a ureterotomy was performed than when it was not. Cats that developed abdominal effusion after surgery were significantly less likely to survive to hospital discharge. Cats that underwent ureteral stenting were significantly more likely to have resolution of azotemia prior to hospital discharge than were cats that underwent ureterotomy alone. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that cats with benign ureteral obstructions treated with ureteral stenting were more likely to have resolution of azotemia prior to hospital discharge, compared with cats undergoing ureterotomy alone. Results of ureteral stenting were encouraging, but further investigation is warranted.

Background: Neutral Protamine Hagedorn human analogue insulin (Humulin N) is commonly used for treatment of canine diabetes mellitus (DM). However, blood glucose and serum insulin concentrations in Humulin N-treated dogs with naturally occurring DM have not been reported.Objective: To investigate blood glucose and serum insulin concentrations in the clinical setting of client-owned Humulin N-treated dogs with naturally occurring, well-regulated DM.Animals: Ten client-owned dogs with naturally occurring, well-regulated DM.Methods: In this clinical study, blood glucose and serum insulin concentrations were measured when dogs received food and insulin (T 0 ), at approximately every half hour for the next 2 hours, and then approximately every 2 hours for an additional 8 hours. Insulin duration of action was defined as the number of hours from T 0 to the lowest blood glucose concentration and until blood glucose concentration returned to an interpolated value of 70% of basal blood glucose concentration (Glucose b ).Results: Mean percent of insulin-induced blood glucose suppression was 49.9 AE 17.1% (median, 46%; range, 29-78%). Insulin duration of action ranged from 4 to 10 hours. Blood glucose concentration increased initially and returned to Glucose b within 0.6-2.2 hours after T 0 in 5 dogs. This initial blood glucose surge then was followed by blood glucose suppression in all 5 dogs.Conclusions and Clinical Importance: These results suggest that Humulin N administered SC twice daily is an effective mode of treatment for dogs with naturally occurring DM. Postprandial hyperglycemia is present in some well-regulated diabetic dogs treated with Humulin N.

Background: Urolithiasis is an important upper and lower urinary tract disease in cats that results in morbidity and mortality.Objective: To describe trends in composition of uroliths in cats and evaluate risk factors related to age, breed, sex, urolith location, and bacterial urolith cultures. Sample Population: A total of 3940 uroliths and the cats from which they were obtained. Methods: The database of the UC Davis Gerald V. Ling Urinary Stone Analysis Laboratory was searched for all urolith submissions from cats between January 2005 and December 2018. Mineral type, age, breed, sex, and urolith location and culture results were recorded. Trends were evaluated and variables compared to evaluate risk factors. Results: A significant decrease in the proportion of calcium oxalate (CaOx)-containing uroliths occurred over time (P = .02), from 50.1% (204/407) of all submissions in 2005 to 37.7% (58/154) in 2018. In contrast, the proportion of struvite-containing uroliths increased significantly (P = .002), from 41.8% (170/407) in 2005 to 54.5% (84/154) in 2018. The proportion of CaOx-containing uroliths in the upper urinary tract was significantly higher compared to the proportion of other urolith types in the upper urinary tract. Urate-containing uroliths were the third most common type (361/3940, 9.2%).Overall, sex and age predispositions were similar to those reported previously.Conclusions and Clinical Importance: The decrease in the proportion of CaOxcontaining uroliths and increase in the proportion of struvite-containing uroliths warrants investigation. Further education regarding the efficacy of medical dissolution of struvite-containing uroliths is recommended.

Background: Lower urinary tract transitional cell carcinoma (TCC) is an important but rarely described disease of cats.Objectives: To report the clinical characteristics, treatments, and outcomes in a cohort of cats with lower urinary tract TCC and to test identified variables for prognostic relevance.Animals: One-hundred eighteen client-owned cats with lower urinary tract carcinoma.Methods: Medical records were retrospectively reviewed to obtain information regarding clinical characteristics, treatments, and outcomes. Recorded variables were analyzed statistically. Results: Median age of affected cats was 15 years (range, 5.0-20.8 years) and median duration of clinical signs was 30 days (range, 0-730 days). The trigone was the most common tumor location (32/118; 27.1%) as assessed by ultrasound examination, cystoscopy, or both. Treatment was carried out in 73 of 118 (61.9%) cats. Metastatic disease was documented in 25 of 118 (21.2%) cats. Median progression-free survival Abbreviations: BUN, blood urea nitrogen; CI, confidence interval; COX, cyclooxygenase; FNA, fine-needle aspirate; HR, hazard ratio; IQR, interquartile range; NSAIDs, nonsteroidal antiinflammatory drugs; OR, odds ratio; TCC, transitional cell carcinoma.and survival time for all cats were 113 days (95% confidence interval [CI], and 155 days (95% CI, 110-222), respectively. Survival increased significantly (P < .001) when comparing cats across the ordered treatment groups: no treatment, treatment without partial cystectomy, and treatment with partial cystectomy. Partial cystectomy (hazard ratio [HR], 0.31; 95% CI, 0.17-0.87) and treatment with nonsteroidal anti-inflammatory drugs (HR, 0.55; 95% CI, 0.33-0.93) were significantly associated with longer survival times.Conclusions and Clinical Importance: The results support treatment using partial cystectomy and NSAIDs in cats with TCC.

Limited evidence-based studies are published regarding management of feline upper and lower urinary tract CaOx stone disease, making this a difficult condition to manage in some cats. Studies designed to evaluate the relationship to dietary modifications, medical management, stress, obesity and surgical techniques are warranted in cats with upper and lower urinary tract CaOx stones.