A Safe, Fibrosis-Mitigating, and Scalable Encapsulation Device Supports Long-Term Function of Insulin-Producing Cells.

Encapsulation and transplantation of insulin-producing cells offer a promising curative treatment for type 1 diabetes (T1D) without immunosuppression. However, biomaterials used to encapsulate cells often elicit foreign body responses, leading to cellular overgrowth and deposition of fibrotic tissue, which in turn diminishes mass transfer to and from transplanted cells. Meanwhile, the encapsulation device must be safe, scalable, and ideally retrievable to meet clinical requirements. Here, a durable and safe nanofibrous device coated with a thin and uniform, fibrosis-mitigating, zwitterionically modified alginate hydrogel for encapsulation of islets and stem cell-derived beta (SC-ß) cells is reported. The device with a configuration that has cells encapsulated within the cylindrical wall, allowing scale-up in both radial and longitudinal directions without sacrificing mass transfer, is designed. Due to its facile mass transfer and low level of fibrotic reactions, the device supports long-term cell engraftment, correcting diabetes in C57BL6/J mice with rat islets for up to 399 days and SCID-beige mice with human SC-ß cells for up to 238 days. The scalability and retrievability in dogs are further demonstrated. These results suggest the potential of this new device for cell therapies to treat T1D and other diseases.

Perioperative characteristics, histologic diagnosis, complications, and outcomes of dogs undergoing percutaneous drainage, sclerotherapy or surgical management of intrarenal cystic lesions: 18 dogs (2004-2021).

BACKGROUND: Canine intrarenal cystic lesions (ICLs) are infrequently reported in the veterinary literature. Several treatment options have been described including cyst fenestration (partial nephrectomy/deroofing) +/- omentalization, sclerotherapy using alcohol as a sclerosing agent, percutaneous cyst drainage (PCD), and ureteronephrectomy. Information regarding presenting clinical signs, physical examination findings, histologic diagnosis and outcomes of dogs with ICLs treated by different methods is limited. Medical records of 11 institutions were retrospectively reviewed to identify dogs that underwent PCD, sclerotherapy, surgical deroofing +/- omentalization, or ureteronephrectomy for management of ICLs from 2004 to 2021. Six weeks postoperative/post-procedural follow-up was required. Cases suspected to represent malignancy on preoperative imaging were excluded. The study objective was to provide information regarding perioperative characteristics, complications, and outcomes of dogs undergoing treatment of ICLs. RESULTS: Eighteen dogs were included, with 24 ICLs treated. Ten had bilateral. There were 15 males and 3 females, with crossbreeds predominating. PCD, sclerotherapy, deroofing and ureteronephrectomy were performed in 5 (5 ICLs treated), 7 (11 ICLs), 6 (6), and 7 (7) dogs, respectively, with 5 dogs undergoing > 1 treatment. Seven dogs experienced 8 complications, with requirement for additional intervention commonest. PCD, sclerotherapy and deroofing resulted in ICL resolution in 0/5, 3/11 and 3/6 treated ICLs, respectively. Histopathology identified renal cysts (RCs) in 7/13 dogs with histopathology available and neoplasia in 6/13 (4 malignant, 2 benign). Of 5 dogs diagnosed histopathologically with neoplasia, cytology of cystic fluid failed to identify neoplastic cells. Among 7 dogs with histologically confirmed RCs, 4 had concurrent ICLs in ipsilateral/contralateral kidney, compared with 2/6 dogs with histologically confirmed neoplasia. CONCLUSIONS: Benign and neoplastic ICLs were approximately equally common and cystic fluid cytology failed to differentiate the 2. Among renal-sparing treatments, deroofing most commonly resulted in ICL resolution. Presence of concurrent ICLs in ipsilateral/contralateral kidney does not appear reliable in differentiating benign from malignant ICLs.

Minimally invasive video-assisted parathyroidectomy in dogs: Technique description and feasibility study.

OBJECTIVE: To describe a minimally invasive approach to the parathyroid gland for the treatment of primary hyperparathyroidism. STUDY DESIGN: Surgical technique description and clinical case report. ANIMALS: Five canine cadavers and 5 client-owned dogs with primary hyperparathyroidism. METHODS: A surgical technique for minimally invasive video-assisted parathyroidectomy (MIVAP), described for humans, was adapted for dogs. With the dog in dorsal recumbency, a 15 mm incision was made on the midline, 1 finger width caudal to the cricoid cartilage of the larynx. A 5 mm 30° rigid endoscope was inserted into the peritracheal space with the aid of a blunt suction dissector, and fine elevators. The parathyroid was subsequently removed using electrocautery and blunt and sharp dissection. The technique was refined in 5 cadaver dogs to assess feasibility, and was subsequently performed in 5 clinical cases. RESULTS: A minimally invasive approach to the parathyroid gland was possible and allowed successful removal of a parathyroid mass in 5 dogs without complication. The use of fluid ingress was trialed in 1 cadaver and not found to be helpful. The use of a blunt suction dissector greatly facilitated dissection of the peritracheal space. CONCLUSION: Minimally invasive video-assisted parathyroidectomy is feasible in dogs and was not associated with complications in 5 clinical cases. CLINICAL SIGNIFICANCE: Minimally invasive techniques tend to reduce morbidity and are popular with pet owners. This study demonstrates that a minimally invasive technique may be considered for parathyroidectomy in dogs.

Designing a retrievable and scalable cell encapsulation device for potential treatment of type 1 diabetes.

Cell encapsulation has been shown to hold promise for effective, long-term treatment of type 1 diabetes (T1D). However, challenges remain for its clinical applications. For example, there is an unmet need for an encapsulation system that is capable of delivering sufficient cell mass while still allowing convenient retrieval or replacement. Here, we report a simple cell encapsulation design that is readily scalable and conveniently retrievable. The key to this design was to engineer a highly wettable, Ca2+-releasing nanoporous polymer thread that promoted uniform in situ cross-linking and strong adhesion of a thin layer of alginate hydrogel around the thread. The device provided immunoprotection of rat islets in immunocompetent C57BL/6 mice in a short-term (1-mo) study, similar to neat alginate fibers. However, the mechanical property of the device, critical for handling and retrieval, was much more robust than the neat alginate fibers due to the reinforcement of the central thread. It also had facile mass transfer due to the short diffusion distance. We demonstrated the therapeutic potential of the device through the correction of chemically induced diabetes in C57BL/6 mice using rat islets for 3 mo as well as in immunodeficient SCID-Beige mice using human islets for 4 mo. We further showed, as a proof of concept, the scalability and retrievability in dogs. After 1 mo of implantation in dogs, the device could be rapidly retrieved through a minimally invasive laparoscopic procedure. This encapsulation device may contribute to a cellular therapy for T1D because of its retrievability and scale-up potential.

Effect of subcutaneous closure technique on incisional complications and postoperative pain in cats undergoing midline celiotomy: A randomized, blinded, controlled trial.

OBJECTIVE: To compare the effect of three methods of subcutaneous tissue closure on postoperative incisional complications and pain in cats. STUDY DESIGN: Single-center, randomized, blinded, controlled trial conducted in a veterinary teaching hospital. ANIMALS: Two hundred ninety-seven cats undergoing midline celiotomy for ovariohysterectomy (n = 280) or other abdominal procedure (n = 17). METHODS: Cats (n = 297) were assigned to one of three subcutaneous closure methods: simple continuous apposition with tacking to the rectus fascia (n = 108, quilting [Q] group); simple continuous apposition (SC; n = 94); no subcutaneous closure (NC; n = 95). Primary outcomes were incidence of seroma formation, postoperative pain, and surgical site infection or dehiscence. Active follow-up was obtained at 10 and 30 days postoperatively. RESULTS: Baseline characteristics did not differ between groups. Seroma was less common in the Q group (13.0%) than in the NC (27.3%) and SC (25.9%) groups (P = .03). Compared with the other two groups, the relative risk of seroma formation in the Q group was 0.49 (95% CI = 0.28-0.86, P = .01). Median mechanical pain thresholds were higher (indicating greater comfort) in cats with subcutaneous sutures (Q and SC = 1.23 [interquartile range (IQR), 0.2-2.6 N], NC = 0.83 [IQR, 0-1.87 N], P = .04) on the day after surgery. CONCLUSION: Closing subcutaneous tissues with a quilting closure pattern reduced seroma formation in cats undergoing celiotomy. CLINICAL SIGNIFICANCE: Placing a quilting suture pattern in the subcutaneous tissues after celiotomy is a simple low-cost measure that reduces seromas in cats. Abstaining from subcutaneous closure cannot be recommended because of increased seroma formation and pain.

Intraoperative and major postoperative complications and survival of dogs undergoing surgical management of epiglottic retroversion: 50 dogs (2003-2017).

OBJECTIVE: To report intraoperative and major postoperative complications in dogs treated surgically for epiglottic retroversion (ER), compare the incidence of major postoperative complications between procedures, and report survival of surgically treated dogs. STUDY DESIGN: Multi-institutional retrospective study. SAMPLE POPULATION: Fifty dogs treated with 78 procedures. METHODS: Medical records of dogs diagnosed and surgically treated for ER from 2003 to 2017 at 11 institutions were reviewed. Complications were divided into intraoperative and major postoperative complications. RESULTS: Intraoperative complications occurred during 2 of 78 (2.6%) procedures. Thirty-six major postoperative complications were documented in 22 dogs after 36 of 74 (48.7%) procedures. Postoperative complications occurred after 7 of 12 (58.3%) nonincisional epiglottopexy, 23 of 43 (53.5%) incisional epiglottopexy, 2 of 4 (50%) partial epiglottectomy, 2 of 12 (16.7%) subtotal epiglottectomy, and 2 of 3 (66.7%) other surgical procedures. Epiglottopexy failure was the most common major postoperative complication. The incidence of major postoperative complications did not differ between procedures (P = .1239), although, when combined, epiglottopexy procedures (30/55) had a higher incidence of complications than epiglottectomy procedures (4/16; P = .048). Thirty (60%) dogs were alive at a median of 928 days (range, 114-2805), 8 (16%) were lost to follow-up after 411 days (range, 43-1158), and 12 (24%) were dead/euthanized after 301.5 days (range, 3-1212). Median survival time was not reached after a median of 716 days. CONCLUSION: Although intraoperative complications were uncommon, major postoperative complications were common, especially after epiglottopexy procedures. CLINICAL SIGNIFICANCE: Although surgical treatment of ER is associated with a high rate of major postoperative complications, especially epiglottopexy procedures, long-term survival can be achieved.

A quilting subcutaneous suture pattern to reduce seroma formation and pain 24 hours after midline celiotomy in dogs: A randomized controlled trial.

OBJECTIVE: To determine the influence of a quilting suture pattern tacking the subcutaneous tissues to the deep fascia on complications after midline celiotomy in dogs. STUDY DESIGN: Single-center, randomized, blinded, controlled trial conducted in a veterinary teaching hospital. ANIMALS: Four hundred thirty-two dogs undergoing midline celiotomy for ovariohysterectomy (n = 249) or other abdominal procedures (n = 183). METHODS: Dogs were randomly assigned to (1) a quilting group, subcutaneous tissue with apposition plus tacking to the rectus fascia or (2) a nonquilting group, with apposition of subcutaneous tissue without tacking. Randomization was stratified on hospital admitting service. Primary outcome was the incidence of incisional seroma. Secondary outcomes included postoperative pain the day after surgery and surgical site infection (SSI). Outcomes were assessed during the first 30 postoperative days. RESULTS: No differences were detected between the quilting group (n = 183) and the nonquilting group (n = 175) in terms of illness severity, surgical procedure performed, surgeon's experience, duration of surgery, intraoperative complications, or methods of surgical closure other than the intervention under study. In an intent-to-treat analysis, the incidence of incisional seroma was lower in the quilting group (odds ratio = 0.30, 95% CI = 0.13-0.67, P = .004). Pain assessed 24 hours postoperatively was lower in the quilting group (P = .03). The incidence of SSI did not differ between groups. CONCLUSION: Tacking the subcutaneous tissues to the deep fascia is indicated to reduce seroma during celiotomy closure.

The pathogenesis of paraesophageal empyema in dogs and constancy of radiographic and computed tomography signs are linked to involvement of the mediastinal serous cavity.

The mediastinal serous cavity is a normal anatomic space in the caudal mediastinum. Aims of this anatomic and case series study were to describe the signs of pathologic expansion of the mediastinal serous cavity observed during computed tomography (CT), review the underlying anatomy, perform a literature review, and evaluate the medical records of several dogs with mediastinal serous cavity empyema (paraesophageal empyema). The mesothelial lined mediastinal serous cavity is a cranial extension of the omental bursa, separated from the peritoneal cavity by the diaphragm, in the dorsal part of the caudal mediastinum, to the right of the esophagus, between the heart base and diaphragm. In five adult, large-breed dogs with surgically and histologically confirmed paraesophageal empyema, macroscopic plant material was found at surgery in two dogs, adherence to adjacent lung was present in three different dogs, accessory lobectomy was performed in two dogs with subacute-chronic pyogranulomatous pneumonia, and one dog had concurrent pyothorax and mediastinitis, but none had esophageal abnormalities. This study expands our understanding of the pathogenesis and basis for the imaging appearance of paraesophageal empyema in dogs by clarifying the underlying anatomic structures that direct development of this condition. The term empyema accurately describes this condition because the purulent material accumulates within an existing body cavity. The study also provides initial evidence that the development of paraesophageal empyema might be due to local extension of lung disease, such as foreign body migration or pneumonia. Computed tomography was helpful for diagnosis, assessing size, and determining the spread of disease.

Clinical features, concurrent disorders, and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome.

OBJECTIVE: To characterize clinical features, comorbidities, frequency of bacterial isolation, and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS). ANIMALS: 168 client-owned cats with S-CCHS. PROCEDURES: Data were prospectively (1980 to 2019) collected regarding clinical features, comorbidities, bacterial infection, illness duration, and treatments. Variables were evaluated for associations with survival time. RESULTS: Median age of cats was 10.0 years, with no breed or sex predilection observed. Common clinical features included hyporexia (82%), hyperbilirubinemia (80%), lethargy (80%), vomiting (80%), jaundice (67%), weight loss (54%), and hypoalbuminemia (50%). Comorbidities included extrahepatic bile duct obstruction (53%), cholelithiasis (42%), cholecystitis (40%), and ductal plate malformation (44%) as well as biopsy-confirmed inflammatory bowel disease (60/68 [88%]) and pancreatitis (41/44 [93%]). Bacterial cultures were commonly positive (69%) despite prebiopsy antimicrobial administration in most cats. Of surgically confirmed choleliths, diagnostic imaging identified only 58%. Among 55 cats with "idiopathic pancreatitis," 28 (51%) were documented to have transiting choleliths, and 20 had pancreatic biopsies confirming pancreatitis. Cholelithiasis (with or without bile duct obstruction) and cholecystectomy were associated with survival advantages. Survival disadvantages were found for leukocytosis, ≥ 2-fold increased alkaline phosphatase, and hyperbilirubinemia. Cholecystoenterostomy had no survival impact. Cats with ductal plate malformations were significantly younger at diagnosis and death than other cats. Chronic treatments with antimicrobials, S-adenosylmethionine, and ursodeoxycholic acid were common postbiopsy. CLINICAL RELEVANCE: S-CCHS in cats was associated with bacterial infection and various comorbidities and may be confused with pancreatitis. Surgically correctable morbidities (ie, cholecystitis, cholecystocholelithiasis) and cholecystectomy provided a significant survival advantage.

Spirocyclic lignans from Guaiacum (Zygophyllaceae) induce apoptosis in human breast cancer cell lines.

We investigated the composition of extracts derived from Guaiacum spp. (Zygophyllaceae), a group of neotropical tree species with varied uses in Central and South American traditional medicine. Activity-guided fractionation of Guaiacum heartwood extracts led to the identification of four new spirocyclic lignans, named ramonanins A-D (1-4). The ramonanins exhibit cytotoxic activity against human breast cancer cell lines with an IC50 value of 18 µM and induce cell death via apoptotic mechanisms. The ramonanins are derived from four units of coniferyl alcohol and feature an unusual spirocyclic ring system.

Preoperative serum C-reactive protein concentration can be used to detect gallbladder rupture in dogs with gallbladder mucocele.

OBJECTIVE: To determine whether serum C-reactive protein (CRP) concentration could be used to detect gallbladder rupture (GBR) prior to surgery in dogs undergoing cholecystectomy for treatment of gallbladder mucocele (GBM). ANIMALS: 45 dogs that underwent cholecystectomy because of GBM at a companion animal referral hospital from 2017 to 2020. PROCEDURES: Electronic medical records were reviewed, and dogs were included if serum CRP concentration had been measured within 24 hours prior to cholecystectomy. Dogs were grouped as to whether the gallbladder was found to be ruptured or intact during surgery. Accuracy of using preoperative CRP concentration to predict GBR was compared with accuracy of abdominal ultrasonography and other preoperative blood tests. RESULTS: GBR was present in 15 dogs at the time of surgery. Median preoperative CRP concentration was significantly higher in dogs with GBR (15.1 mg/dL; interquartile range, 7.4 to 16.8 mg/dL) than in dogs with an intact gallbladder (2.65 mg/dL; interquartile range, 0.97 to 13.4 mg/dL). Sensitivity, specificity, and accuracy of using preoperative CRP concentration to predict GBR were 100%, 67%, and 78%, respectively. CLINICAL RELEVANCE: Measurement of preoperative CRP concentration provided excellent sensitivity and moderate specificity for detection of GBR in dogs undergoing cholecystectomy because of GBM. Accuracy of using preoperative CRP concentration for detection of GBR was not superior to the accuracy of preoperative abdominal ultrasonography. However, when CRP concentration was combined with results of ultrasonography, the sensitivity, specificity, and accuracy for detection of GBR were 100%, 93%, and 96%, respectively.

Comparison of patient outcomes following enterotomy versus intestinal resection and anastomosis for treatment of intestinal foreign bodies in dogs.

OBJECTIVE: To quantify the relative risk of intestinal dehiscence in dogs undergoing intestinal resection and anastomosis (IRA), compared with enterotomy, for surgical management of small intestinal foreign bodies, and to evaluate the association between nasogastric tube placement for early enteral nutrition (EEN) and hospitalization time. ANIMALS: 211 dogs undergoing 227 surgeries for intestinal foreign body removal. PROCEDURES: Medical records were reviewed for dogs undergoing a single-site sutured enterotomy or IRA for foreign body intestinal obstruction between May 2008 and April 2018. Multivariable logistic regression was used to quantify the association between surgical procedure and dehiscence. Multiple linear regression was used to quantify the association of nasogastric tube placement with total hospitalization time. RESULTS: Dehiscence rates were 3.8% (7/183) and 18.2% (8/44) for enterotomy and IRA, respectively. Overall dehiscence rate for all surgeries was 6.6% (15/227). The odds of intestinal dehiscence for IRA were 6.09 times (95% CI, 1.89 to 19.58) the odds for enterotomy. An American Society of Anesthesiologists score > 3 (OR, 4.49; 95% CI, 1.43 to 14.11) and an older age (OR, 1.02 [95% CI, 1.01 to 1.02] for each 1-month increase in age) were significantly associated with greater odds of intestinal dehiscence, regardless of surgical procedure. Placement of a nasogastric tube was not associated with intestinal dehiscence or decreased total hospitalization time when controlling for the year of surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Patients undergoing IRA were at a significantly higher risk of intestinal dehiscence, compared with patients undergoing enterotomy. Although this finding should not be used to recommend enterotomy over IRA, this information may be useful in guiding owner expectations and postoperative monitoring.

Relationships between congenital peritoneopericardial diaphragmatic hernia or congenital central diaphragmatic hernia and ductal plate malformations in dogs and cats.

OBJECTIVE: To characterize the association between peritoneopericardial diaphragmatic hernia (PPDH) or congenital central diaphragmatic hernia (CCDH) and ductal plate malformations (DPMs) in dogs and cats. ANIMALS: 18 dogs and 18 cats with PPDH or CCDH and 19 dogs and 18 cats without PPDH or CCDH. PROCEDURES: Evaluation of clinical details verified PPDH or CCDH and survival times. Histologic features of nonherniated liver samples were used to categorize DPM. Immunohistochemical staining for cytokeratin-19 distinguished bile duct profiles per portal tract and for Ki-67-assessed cholangiocyte proliferation. Histologic features of herniated liver samples from PPDH or CCDH were compared with those of pathological controls (traumatic diaphragmatic hernia, n = 6; liver lobe torsion, 6; ischemic hepatopathy, 2). RESULTS: DPM occurred in 13 of 18 dogs with the proliferative-like phenotype predominating and in 15 of 18 cats with evenly distributed proliferative-like and Caroli phenotypes. Congenital hepatic fibrosis DPM was noted in 3 dogs and 2 cats and renal DPM in 3 dogs and 3 cats. No signalment, clinical signs, or clinicopathologic features discriminated DPM. Kaplan Meier survival curves were similar in dogs and cats. Bile duct profiles per portal tract in dogs (median, 5.0; range, 1.4 to 100.8) and cats (6.6; 1.9 to 11.0) with congenital diaphragmatic hernias significantly exceeded those in healthy dogs (1.4; 1.2 to 1.6) and cats (2.3; 1.7 to 2.6). Animals with DPM lacked active cholangiocyte proliferation. Histologic features characterizing malformative bile duct profiles yet without biliary proliferation were preserved in herniated liver lobes in animals with DPM. CONCLUSIONS AND CLINICAL RELEVANCE: DPM was strongly associated with PPDH and CCDH. Because DPM can impact health, awareness of its coexistence with PPDH or CCDH should prompt biopsy of nonherniated liver tissue during surgical correction of PPDH and CCDH.

A nanofibrous encapsulation device for safe delivery of insulin-producing cells to treat type 1 diabetes.

Transplantation of stem cell-derived ß (SC-ß) cells represents a promising therapy for type 1 diabetes (T1D). However, the delivery, maintenance, and retrieval of these cells remain a challenge. Here, we report the design of a safe and functional device composed of a highly porous, durable nanofibrous skin and an immunoprotective hydrogel core. The device consists of electrospun medical-grade thermoplastic silicone-polycarbonate-urethane and is soft but tough (~15 megapascal at a rupture strain of >2). Tuning the nanofiber size to less than ~500 nanometers prevented cell penetration while maintaining maximum mass transfer and decreased cellular overgrowth on blank (cell-free) devices to as low as a single-cell layer (~3 micrometers thick) when implanted in the peritoneal cavity of mice. We confirmed device safety, indicated as continuous containment of proliferative cells within the device for 5 months. Encapsulating syngeneic, allogeneic, or xenogeneic rodent islets within the device corrected chemically induced diabetes in mice and cells remained functional for up to 200 days. The function of human SC-ß cells was supported by the device, and it reversed diabetes within 1 week of implantation in immunodeficient and immunocompetent mice, for up to 120 and 60 days, respectively. We demonstrated the scalability and retrievability of the device in dogs and observed viable human SC-ß cells despite xenogeneic immune responses. The nanofibrous device design may therefore provide a translatable solution to the balance between safety and functionality in developing stem cell-based therapies for T1D.

Dyspnea caused by epiglottic retroversion in two dogs.

CASE DESCRIPTION: An 8-year-old castrated male Boxer and a 10-year-old spayed female Yorkshire Terrier were evaluated because of dyspnea. In both dogs, the dyspnea persisted after elongated soft palate resection. CLINICAL FINDINGS: Laryngoscopic examination revealed caudal displacement of the epiglottis into the rima glottidis in both dogs. Excessive mobility of the epiglottis during respiration with episodic obstruction of the rima glottidis by the epiglottis was observed during fluoroscopic examination. TREATMENT AND OUTCOME: The epiglottis of both dogs was fixed in a horizontal plane by resection of a band of oral mucosa at the base of the epiglottis and closure of the mucosal defect with sutures. Fixation of the epiglottis resolved the dyspnea in both dogs. CLINICAL RELEVANCE: Excessive mobility of the epiglottis can predispose to glottic obstruction and cause dyspnea in dogs. Fixation of the epiglottis in a horizontal plane may resolve dyspnea caused by epiglottic retroversion in dogs.

Engineering transferrable microvascular meshes for subcutaneous islet transplantation.

The success of engineered cell or tissue implants is dependent on vascular regeneration to meet adequate metabolic requirements. However, development of a broadly applicable strategy for stable and functional vascularization has remained challenging. We report here highly organized and resilient microvascular meshes fabricated through a controllable anchored self-assembly method. The microvascular meshes are scalable to centimeters, almost free of defects and transferrable to diverse substrates, ready for transplantation. They promote formation of functional blood vessels, with a density as high as ~220 vessels mm-2, in the poorly vascularized subcutaneous space of SCID-Beige mice. We further demonstrate the feasibility of fabricating microvascular meshes from human induced pluripotent stem cell-derived endothelial cells, opening a way to engineer patient-specific microvasculature. As a proof-of-concept for type 1 diabetes treatment, we combine microvascular meshes and subcutaneously transplanted rat islets and achieve correction of chemically induced diabetes in SCID-Beige mice for 3 months.

Evaluation of atrial fibrillation induced during anesthesia with fentanyl and pentobarbital in German Shepherd Dogs with inherited arrhythmias.

OBJECTIVE: To determine the type of atrial fibrillation induced by use of 2 pacing protocols during fentanyl and pentobarbital anesthesia before and after administration of atropine and to determine the organization of electrical activity in the left and right atria during atrial fibrillation in German Shepherd Dogs. ANIMALS: 7 German Shepherd Dogs. PROCEDURES: Extrastimulus and pacedown protocols were performed before and after atropine administration. Monophasic action potential spectral entropy and mean dominant frequency were calculated during atrial fibrillation. RESULTS: Atrial fibrillation occurred spontaneously in 6 of 7 dogs. All 7 dogs had atrial fibrillation induced. Sustained atrial fibrillation occurred in 13 of 25 (52%) episodes induced by the extrastimulus protocol and in 2 of 12 episodes of atrial fibrillation induced by pacedown. After atropine administration, sustained atrial fibrillation did not occur, and the duration of the nonsustained atrial fibrillation (6 episodes in 2 dogs of 1 to 26 seconds) was significantly shorter than before atropine administration (25 episodes in 7 dogs of 1 to 474 seconds). The left atrium (3.67 +/- 0.08) had lower spectral entropy than the right atrium (3.81 +/- 0.03), indicating more electrical organization in the left atrium. The mean dominant frequency was higher in the left atrium in 3 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Atrial fibrillation developed spontaneously and was induced in German Shepherd Dogs under fentanyl and pentobarbital anesthesia. Electrical activity was more organized in the left atrium than in the right atrium as judged by use of spectral entropy.

Use of vascular access ports in femoral veins of dogs and cats with cancer.

OBJECTIVE: To evaluate long-term function of vascular access ports (VAPs) implanted in the femoral vein of dogs and cats undergoing cancer treatment. DESIGN: Prospective clinical study. ANIMALS: 3 dogs and 6 cats treated via chemotherapy or radiation. PROCEDURES: VAPs were surgically implanted in the left femoral vein of 3 dogs and 6 cats over a 1-year period. Injection port location was alternated to either a caudal thoracic or ilial location in each patient. Duration of VAP function, ease of infusion, and ease of aspiration through the VAPs were recorded, and associated complications were assessed at each VAP use. Client satisfaction with VAP placement was evaluated by use of a questionnaire. RESULTS: Primary uses of the VAPs included blood sampling and delivering sedative or chemotherapeutic drugs. Median duration of successful infusion was 147 days (range, 60 to 370 days), and median duration of successful aspiration was 117 days (range, 10 to 271 days). The frequency of signs of VAP-related discomfort was low (7% of patient observations). Clients were satisfied with their decision to use VAPs. Complications included partial (n = 7) or complete (2) VAP occlusion, port migration (1), and presumptive infection (1). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that VAP implantation into the femoral vein provides an acceptable means of chronic venous access in dogs and cats undergoing cancer treatment.

Use of vascular access ports with intrathoracic drains for treatment of pleural effusion in three dogs.

CASE DESCRIPTION: 3 dogs (9 to 12 years old) were evaluated because of recurrent pleural effusion that was refractory to treatment of the underlying cause. CLINICAL FINDINGS: Dogs were evaluated because of cough, dyspnea, tachypnea, or lethargy or a combination of these clinical signs. Radiography, ultrasonography, or thoracocentesis were used to confirm the presence of pleural fluid in each dog. A neoplastic cause of pleural effusion was confirmed in 2 dogs. In 1 dog, fasciitis of the mediastinum and the left parietal pleura was diagnosed, with no evidence of neoplasia. TREATMENT AND OUTCOME: Each dog was anesthestized, and thoracotomy was performed with manual perforation of the mediastinum. Permanent, subcutaneously placed vascular access ports were attached to intrathoracic, Jackson-Pratt drain tubing for repeated drainage of pleural fluid. Drains were used successfully in the 3 dogs for periods of 6 weeks, 11 weeks, and > 3 years. CLINICAL RELEVANCE: Findings suggest that subcutaneous vascular access ports attached to intrathoracic drain tubing may be an effective way to remove recurrent pleural effusion in dogs.

Live Births from Domestic Dog (Canis familiaris) Embryos Produced by In Vitro Fertilization.

Development of assisted reproductive technologies (ART) in the dog has resisted progress for decades, due to their unique reproductive physiology. This lack of progress is remarkable given the critical role ART could play in conserving endangered canid species or eradicating heritable disease through gene-editing technologies-an approach that would also advance the dog as a biomedical model. Over 350 heritable disorders/traits in dogs are homologous with human conditions, almost twice the number of any other species. Here we report the first live births from in vitro fertilized embryos in the dog. Adding to the practical significance, these embryos had also been cryopreserved. Changes in handling of both gametes enabled this progress. The medium previously used to capacitate sperm excluded magnesium because it delayed spontaneous acrosome exocytosis. We found that magnesium significantly enhanced sperm hyperactivation and ability to undergo physiologically-induced acrosome exocytosis, two functions essential to fertilize an egg. Unlike other mammals, dogs ovulate a primary oocyte, which reaches metaphase II on Days 4-5 after the luteinizing hormone (LH) surge. We found that only on Day 6 are oocytes consistently able to be fertilized. In vitro fertilization of Day 6 oocytes with sperm capacitated in medium supplemented with magnesium resulted in high rates of embryo development (78.8%, n = 146). Intra-oviductal transfer of nineteen cryopreserved, in vitro fertilization (IVF)-derived embryos resulted in seven live, healthy puppies. Development of IVF enables modern genetic approaches to be applied more efficiently in dogs, and for gamete rescue to conserve endangered canid species.