The aim of this study was to create a surgical guide platform that maintains its integrity while the surgeon performs an intestinal anastomosis or another similar procedure, which then breaks apart and is eliminated from the body in a controlled manner. The device contains mixed polymeric structures that give it a controlled rate of disassembly that could meet the requirements of a specific surgical purpose. The intraluminal anastomotic guide was manufactured as a hollow cylinder composed of layers of porous polyurethane/PCL with polyvinylpyrrolidone as the binding agent similar to a “brick–mortar” architecture. This combination of polymeric structures is a promising manufacturing method from which a variety of tunable devices can be fabricated for specific medical procedures and site-specific indications. The guide was designed to rapidly disassemble within the intestinal lumen after use, reliably degrading while maintaining sufficient mechanical rigidity and stability to support manipulation during complex surgical procedures. The nature of the device’s disassembly makes it suitable for use in hollow structures that discharge their contents, resulting in their elimination from the body. A swine model of intestinal anastomosis was utilized to validate the use and function of the device.

OBJECTIVE To examine changes occurring in normal pelvic suspensory ligaments (SLs) of horses after denervating these ligaments and to investigate the effect chronic inflammation might have on these changes. ANIMALS 10 horses. PROCEDURES The SL of 1 randomly selected pelvic limb of each of 5 horses was injected with collagenase to induce desmitis, and 42 days later, the proximal aspect of both pelvic SLs were denervated. The SLs were harvested 120 days after being denervated, and the morphological and histological characteristics of each collagenase-injected, denervated SL were compared with those of the contralateral, non-injected, denervated SL. All denervated SLs were compared with non-denervated pelvic SLs harvested from 5 horses similar in weight and age. RESULTS The mean width and the cross-sectional area of the musculature of all denervated SLs were significantly less than that of the non-denervated ligaments. The mean thickness of collagenase-injected denervated ligaments, but not that of the non-injected denervated ligaments, was significantly less than that of the non-denervated ligaments. Histological abnormalities typical of neurogenic muscular atrophy were observed in all denervated ligaments. CLINICAL RELEVANCE Loss of motor neuronal input to the proximal aspect of the SL of the pelvic limb of horses causes neurogenic atrophy of the musculature in that portion of the ligament. Denervating a SL of a pelvic limb may weaken the ligament, increasing its risk of injury. Chronic inflammation of the SL before neurectomy may exacerbate atrophy of the musculature after neurectomy.

Surgical site infections (SSIs) are a common complication following orthopedic surgery. SSIs may occur secondary to traumatic or contaminated wounds or may result from invasive procedures. The development of biofilms is often associated with implanted materials used to stabilize injuries and to facilitate healing. Regardless of the source, SSIs can be challenging to treat. This has led to the development of devices that act simultaneously as local antibiotic delivery vehicles and as scaffolds for tissue regeneration. The goal for the aforementioned devices is to increase local drug concentration in order to enhance bactericidal activity while reducing the risk of systemic side effects and toxicity from the administered drug. The aims of this study were to assess the effect of antibiotic loading of a collagen matrix on the tissue integration of the matrix using a rat mandibular defect model. We hypothesized that the collagen matrix could load and elute gentamicin, that the collagen matrix would be cytocompatible in vitro, and that the local delivery of a high dose of gentamicin via loaded collagen matrix would negatively impact the tissue–scaffold interface. The results indicate that the collagen matrix could load and elute the antimicrobial gentamicin and that it was cytocompatible in vitro with or without the presence of gentamicin and found no significant impact on the tissue–scaffold interface when the device was loaded with a high dose of gentamicin.

Infection is a common complication in orthopedic surgery, and it is often challenging to prevent or eliminate bacterial infection. Treatment is complicated by biofilm formation, insufficient antibiotic penetration, and systemic side effects associated with prolonged antibiotic administration. The desire to eliminate bacterial infection while minimizing side effects has inspired the creation of local drug delivery systems for local antibiotic delivery. Challenges accompanying the use of local drug delivery devices include: foreign body reaction, bacterial colonization on the device, and the risk of prolonged subtherapeutic antibiotic release that could promote antimicrobial resistance (AMR). This study aimed to evaluate the antibiotic elution profile and cytocompatibility, in vitro, and the effect of local delivery of high dose gentamicin on the tissue‐scaffold interface, in vivo, with a commercially available collagen matrix (Fibro Gide, Geistlich) selected as the drug delivery vehicle. Our hypothesis was that the gentamicin impregnated scaffolds would be cytocompatible, would elute gentamicin with an initial burst release, and that the gentamicin impregnated scaffolds would negatively impact the tissue‐scaffold interface in vivo. Cytocompatibility testing was performed using 3T3‐E1 murine pre‐osteoblast cells, cultured in standard media and media spiked with increasing doses of gentamicin (50mg/mL and 100mg/mL). Results of cell proliferation assays, calcein AM staining, and histology of the in vitro scaffolds indicated that the gentamicin impregnated scaffolds were cytocompatible. In vitro gentamicin elution was characterized by an initial burst release of antibiotic followed by gradual, sustained low‐concentration release. In vivo assessment of tissue‐scaffold interfaces was performed using a rat mandible defect model. Surgical defects were created unilaterally in the mandible of 12 rats and scaffolds were placed within the defect (n=6, 40mg/kg gentamicin; n=6, native scaffold). Rectal culture swabs were collected throughout the study to evaluate for the development of AMR. Histopathology of the tissue‐scaffold interface was performed on mandible defects harvested 28 days after implantation. AMR to gentamicin was not detected at any timepoint. Histopathology results showed no significant difference in tissue integration between the native and gentamicin impregnated groups. Based on the results of this study, the collagen matrix was cytocompatible, capable of eluting gentamicin for a period of 14 days, and local delivery of a high dose of gentamicin did not significantly alter the tissue‐scaffold interface. This collagen matrix represents a promising device for utilization in local drug delivery. This model and drug delivery platform may be used for future studies to evaluate various drugs and their effects on infection, AMR, and tissue‐scaffold integration.

Two rock hyraxes (Procavia capensis), from the Chattanooga Zoo, were submitted separately for autopsy at the University of Tennessee Veterinary Medical Center. The first was a 4-y-old intact female that died without premonitory signs and the second was a 10-y-old intact male that was euthanized because of severe renal disease. Microscopically, the lungs of both hyraxes had multifocal-to-coalescing, <1-mm diameter aggregates of epithelioid macrophages separated by streams of fibrous tissue. Macrophages contained intracytoplasmic, clear, acicular, birefringent crystals. Transmission electron microscopy and energy-dispersive x-ray spectroscopy findings on the lung samples were consistent with silica crystal deposition. The hyraxes had been housed together on commercially sourced play sand composed of 99-99.5% quartz, a crystalline silica polymorph. The microscopic findings, transmission electron microscopy, and energy-dispersive x-ray spectroscopy of the intrahistiocytic crystals, in addition to the history of exposure to crystalline silica, were consistent with pulmonary silicosis. Pulmonary silicosis has not been reported previously in rock hyraxes, to our knowledge.

Objective To determine the effect of a novel scaffold, designed for use in bone regeneration, on healing of splint bone segmental defects in mares. Study design In vivo experimental study. Sample population Five adult mares (4-10 years old; mean weight, 437.7 kg +/- 29 kg). Methods Bilateral 2-cm full-thickness defects were created in the fourth metacarpal bones (MCIV) of each horse. Each defect was randomly assigned to either a novel scaffold treatment (n = 5) or an untreated control (n = 5). The scaffold was composed of polyurethane, hydroxyapatite, and decellularized bone particles. Bone healing was assessed for a period of 60 days by thermography, ultrasonography, radiography, and computed tomography (CT). Biopsies of each defect were performed 60 days after surgery for histological evaluation. Results On the basis of radiographic analysis, scaffold-treated defects had greater filling (67.42% +/- 26.7%) compared with untreated defects (35.88% +/- 32.7%; P = .006). After 60 days, CT revealed that the density of the defects treated with the scaffolds (807.80 +/- 129.6 Hounsfield units [HU]) was greater than density of the untreated defects (464.80 +/- 81.3 HU; P = .004). Evaluation of histology slides provided evidence of bone formation within an average of 9.43% +/- 3.7% of the cross-sectional area of scaffolds in contrast to unfilled defects in which connective tissue was predominant throughout the biopsy specimens. Conclusion The novel scaffold was biocompatible and supported bone formation within the MCIV segmental defects. Clinical significance This novel scaffold offers an effective option for filling bone voids in horses when support of bone healing is indicated.

Peptide p5R is a synthetic, polybasic, heparin-binding peptide that preferentially reacts with amyloid deposits in vivo and in tissue sections. Basic fibroblast growth factor (bFGF1) similarly interacts with heparin-like molecules, notably heparan sulfate proteoglycans (HSPG), in the extracellular matrix and on cell surfaces. The aim of this study was to compare the biodistribution of p5R and bFGF in healthy mice as well as those with systemic inflammation-associated amyloidosis (AA), which contains HSPG, by using SPECT/CT imaging, tissue biodistribution measurements and micro-autoradiography. Although both proteins are known to bind heparan sulfate, their biodistribution was remarkably different in the healthy and diseased animals. Imaging revealed uptake of both radiolabeled proteins in the liver, spleen, and kidneys of mice with amyloidosis; however, 125I-bFGF, but not 125I-p5R, was observed in normal tissue at sites of HSPG expression, including the hepatic and splenic sinusoids and renal glomerulae. Microautoradiography demonstrated that while p5R bound exclusively to amyloid deposits in the spleen and liver of AA mice, bFGF had a broader binding pattern. Consequently, even though bFGF and p5R both interact with heparan sulfate moieties, p5R binding was restricted to HSPG in amyloid deposits and did not bind HSPG in healthy tissues, whereas bFGF preferentially reacted with HSPG in normal tissue. The data suggest that peptide p5R selectively binds HSPG in amyloid and that the HSPG in healthy tissue, recognized by bFGF, is not targeted by the peptide.

Various conditions in human and veterinary medicine require intestinal resection and anastomosis, and complications from these procedures are frequent. A rapidly collapsible anastomotic guide was developed for small intestinal end-to-end anastomosis and was investigated in order to assess its utility to improve the anastomotic process and to potentially reduce complication rates. A complex manufacturing method for building a polymeric device was established utilizing biocompatible and biodegradable polyvinylpyrrolidone and polyurethane. This combination of polymers would result in rapid collapse of the material. The guide was designed as a hollow cylinder composed of overlaying shingles that separate following exposure to moisture. An in vivo study was performed using commercial pigs, with each pig receiving one standard handsewn anastomosis and one guide-facilitated anastomosis. Pigs were sacrificed after 13 days, at which time burst pressure, maximum luminal diameter, and presence of adhesions were assessed. Burst pressures were not statistically different between treatment groups, but in vivo anastomoses performed with the guide withstood 10% greater luminal burst pressure and maintained 17% larger luminal diameter than those performed using the standard handsewn technique alone. Surgeons commented that the addition of a guide eased the performance of the anastomosis. Hence, a rapidly collapsible anastomotic guide may be beneficial to the performance of intestinal anastomosis.

Background Human urothelial carcinoma (UC) has a high tendency to recur and progress to life-threatening advanced diseases. Advanced therapeutic regimens are needed to control UC development and recurrence. Methods We pursued in vitro and in vivo studies to understand the ability of a triple combination of gemcitabine, romidepsin, and cisplatin (Gem+Rom+Cis) to modulate signalling pathways, cell death, drug resistance, and tumour development. Results Our studies verified the ability of Gem+Rom+Cis to synergistically induce apoptotic cell death and reduce drug resistance in various UC cells. The ERK pathway and reactive oxygen species (ROS) played essential roles in mediating Gem+Rom+Cis-induced caspase activation, DNA oxidation and damage, glutathione reduction, and unfolded protein response. Gem+Rom+Cis preferentially induced death and reduced drug resistance in oncogenic H-Ras-expressing UC vs. counterpart cells that was associated with transcriptomic profiles related to ROS, cell death, and drug resistance. Our studies also verified the efficacy and safety of the Gem plus Rom+Cis regimen in controlling UC cell-derived xenograft tumour development and resistance. Conclusions More than 80% of UCs are associated with aberrant Ras-ERK pathway. Thus the compensatory combination of Rom with Gem and Cis should be seriously considered as an advanced regimen for treating advanced UCs, especially Ras-ERK-activated UCs.

Background: Few reports of Echinococcus granulosus have been described in the Unites States; however, the geographical distribution of Echinococcus spp. in wild hosts is increasing consequent to human activities. Methods:We investigated the prevalence of Echinococcus spp. in re-established elk ( Cervus canadensis ) populations in the North Cumberland Wildlife Management Area and the Great Smoky Mountains National Park via a retrospective analysis of banked elk tissues and an examination of intestinal contents from 11 coyotes ( Canis latrans ) from the North Cumberland Wildlife Management Area. Results: Four elk were PCR and sequence positive for E. canadensis . Each sequence had 98% or greater coverage and identity to multiple E. canadensis genotypes in Genbank. Adult Echinococcus spp. were not detected in any of the coyotes examined in this study. Conclusions: Continued surveillance of this disease in susceptible species in these areas is warranted, and these data further underscore the risk of zoonotic pathogen introduction secondary to wildlife translocation.

Urinary bladder cancer (UBC) is the fifth-most common cancer in the United States, and urothelial carcinomas (UCs) account for more than 90% of UBCs. Although current therapies are effective in the short-term treatment of UCs, the high tendency (>50%) for them to recur and progress to life threatening, advanced muscle-invasive UCs requires life-long surveillance with extended medical care. Thus, it still requires extensive therapeutic development to achieve an effective control of UC recurrence and improve the response rate and overall survival for UC patients. To develop effective and safe regimens to control the development and recurrence of advanced UCs, we investigated the efficacy of rationalized combination regimens in controlling UC cells in vitro and UC cell-derived xenografts (CDXs) in vivo. Our in vitro studies identified a triple combination of gemcitabine, romidepsin, and cisplatin, which are all FDA-approved anticancer agents, effective in synergistically inducing death and reducing drug resistance of various UC cell lines. Our studies also revealed that UC-associated aberrant pathways, including mitochondrial reactive oxygen species (ROS) and the ERK-Nox pathway, which were already induced in UC cells, were enhanced by the triple combination regimen to play essential roles for inducing apoptosis and reducing resistance. We also detected that the unfolded protein response played a role in modulating cell death induced by the regimen. Our in vivo studies used a tolerable protocol for administering combination regimens into animals. Our studies verified the efficacy of the triple combination gemcitabine plus romidepsin and cisplatin regimen, versus double combination regimens, in controlling UC CDXs in immune-deficient mice. In conclusion, our studies indicated that a rationalized triple combination of gemcitabine plus romidepsin and cisplatin regimen was more effective than double combination regimens in modulating UC-associated vulnerable aberrant pathways and controlling UC tumor development and recurrence in animals with low tolerable/ reversible adverse effects. Thus, the triple combination gemcitabine plus romidepsin and cisplatin regimen should be promptly considered as an advanced treatment over the conventional double combination gemcitabine plus cisplatin regimen in clinical trials in order to control advanced UCs.Citation Format: Hwa-Chain R. Wang, Pawat Pattarawat, Jinquan Wang, Robert Donnell. Targeting vulnerable aberrant cancer-associated pathways by rationalized triple combination regimens to effectively control urothelial carcinoma cells in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2076.

Background Conventional cystoscopy can detect advanced stages of bladder cancer; however, it has limitations to detect bladder cancer at the early stages. Fluorocoxib A, a rhodamine-conjugated analog of indomethacin, is a novel fluorescent imaging agent that selectively targets cyclooxygenase-2 (COX-2)-expressing cancers. Methods In this study, we have used a carcinogen N-butyl-N-4-hydroxybutyl nitrosamine (BBN)-induced bladder cancer immunocompetent mouse B6D2F1 model that resembles human high-grade invasive urothelial carcinoma. We evaluated the ability of fluorocoxib A to detect the progression of carcinogen-induced bladder cancer in mice. Fluorocoxib A uptake by bladder tumors was detected ex vivo using IVIS optical imaging system and Cox-2 expression was confirmed by immunohistochemistry and western blotting analysis. After ex vivo imaging, the progression of bladder carcinogenesis from normal urothelium to hyperplasia, carcinoma-in-situ and carcinoma with increased Ki67 and decreased uroplakin-1A expression was confirmed by histology and immunohistochemistry analysis. Results The specific uptake of fluorocoxib A correlated with increased Cox-2 expression in progressing bladder cancer. In conclusion, fluorocoxib A detected the progression of bladder carcinogenesis in a mouse model with selective uptake in Cox-2-expressing bladder hyperplasia, CIS and carcinoma by 4- and 8-fold, respectively, as compared to normal bladder urothelium, where no fluorocoxib A was detected. Conclusions Fluorocoxib A is a targeted optical imaging agent that could be applied for the detection of Cox-2 expressing human bladder cancer.

Despite treatment, >50% of urothelial carcinomas (UCs) recur and progress to life-threatening, advanced UCs. The double combination gemcitabine+cisplatin (Gem+Cis) regimen is a standard treatment for advanced UCs. Gem is a DNA synthesis-inhibiting agent, and Cis is a platinum-based, DNA-damaging agent. However, despite the initial high response rates with Gem+Cis, the overall 5-year survival rate of advanced UC patients is less than 35% largely due to drug resistance and cancer recurrence. Thus, there is a critical need to identify advanced therapeutic regimens to effectively control advanced UCs. More than 80% of UCs are associated with the aberrant induction of receptor tyrosine kinases (RTKs) to Ras to the ERK pathway. Advanced UCs are frequently accompanied with the aberrant elevation of reactive oxygen species (ROS). To efficiently pursue effective regimens, we studied combinations of FDA-approved agents to synergistically induce and reduce cancer cell death and drug resistance, respectively. Our in vitro studies detected that the integration of the histone deacetylase inhibitor romidepsin (Rom) into the Gem+Cis regimen (Gem+Rom+Cis) resulted in synergistically inducing death and suppressing drug resistance of UC cells. Instead of inhibition, Gem+Rom+Cis enhanced the aberrant RTK-Ras-ERK pathway and ROS in UC cells, along with DNA synthesis inhibition and DNA damage, to induce caspase activation and PARP proteolysis, causing cell death. In addition, our studies revealed that Gem+Rom+Cis was able to enhance the binding immunoglobulin protein (BiP). BiP, the key modulator for the unfolded protein response (UPR), is known to support tumorigenesis, cytoprotection, and drug resistance. Interestingly, our studies indicated a novel role of elevated BiP in supporting cell death but not cytoprotection. Our in vivo studies identified a tolerable protocol for administering combination regimens into animals. We also determined that the triple combination Gem+Rom+Cis regimen was efficacious in controlling UC xenografts in immune-deficient mice. The current therapeutic mainstream emphasizes the inhibition of aberrant pathways in order to regain control of cancer cell growth; however, preclinical and clinical studies have shown that inhibiting one pathway may result in the compensatory activation of other pathways to rescue cancer cells, leading to drug resistance and cancer recurrence. In contrast, our novel results indicated that Gem+Rom+Cis was able to enhance the aberrant Ras-ERK pathway, ROS, and BiP, leading to enhanced cell death and reduced drug resistance in UC cells. In conclusion, our studies identified a safe triple combination Gem+Rom+Cis regimen, effectively modulating UC-associated aberrant pathways and controlling UC tumor development in animals. The triple combination Gem+Rom+Cis regimen should be promptly considered as an advanced treatment over the conventional double combination Gem+Cis regimen in clinical trials in order to control advanced UCs, reduce mortality, and improve UC patients’ quality of life. Citation Format: Hwa-Chain Wang, Pawat Pattarawat, Shelby Wallace, Robert Donnell. Targeting aberrant pathways by an advanced combination regimen to effectively and safely control urothelial carcinoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C038. doi:10.1158/1535-7163.TARG-19-C038

Case summary An adult female spayed Siamese-cross cat of unknown age was presented for bilateral hemorrhagic otorrhea. Nasopharyngeal polyps were diagnosed by CT and biopsy; bilateral ventral bulla osteotomies were performed. Episodic epistaxis, otic hemorrhage and hemoptysis with respiratory distress progressed over 18 months. Systolic blood pressure, complete blood count, plasma biochemistries, prothrombin time, partial thromboplastin time and coagulation factor 12, 9 and 8 activities were normal. Serial thoracic radiographs revealed patchy interstitial to alveolar patterns. Airway hemorrhage prevented diagnostic bronchoscopy. Respiratory hemorrhage was ultimately fatal. Amyloid deposition was identified in pulmonary vasculature, bronchial wall, lymphoid tissues, nasal-pharyngeal tissue and tympanic bullae based on microscopic examination and confirmed by Congo red staining with green birefringence under polarized light. Relevance and novel information Amyloidosis should be considered as a differential diagnosis in cats with spontaneous hemorrhage of the respiratory or otic tracts. Although systemic amyloidosis is associated with a grave prognosis, this case suggests that prolonged survival is possible after the initial onset of signs in cats with pulmonary amyloidosis.

Horses are widely used as large animal preclinical models for cartilage repair studies, and hence, there is an interest in using equine synovial fluid-derived mesenchymal stem cells (SFMSCs) in research and clinical applications. Since, we have previously reported that similar to bone marrow-derived MSCs (BMMSCs), SFMSCs may also exhibit donor-to-donor variations in their stem cell properties; the current study was carried out as a proof-of-concept study, to compare the in vivo potential of equine BMMSCs and SFMSCs in articular cartilage repair. MSCs from these two sources were isolated from the same equine donor. In vitro analyses confirmed a significant increase in COMP expression in SFMSCs at day 14. The cells were then encapsulated in neutral agarose scaffold constructs and were implanted into two mm diameter full-thickness articular cartilage defect in trochlear grooves of the rat femur. MSCs were fluorescently labeled, and one week after treatment, the knee joints were evaluated for the presence of MSCs to the injured site and at 12 weeks were evaluated macroscopically, histologically, and then by immunofluorescence for healing of the defect. The macroscopic and histological evaluations showed better healing of the articular cartilage in the MSCs' treated knee than in the control. Interestingly, SFMSC-treated knees showed a significantly higher Col II expression, suggesting the presence of hyaline cartilage in the healed defect. Data suggests that equine SFMSCs may be a viable option for treating osteochondral defects; however, their stem cell properties require prior testing before application.

A 20-y-old female llama ( Lama glama) was euthanized after a history of chronic dyspnea and osteoarthritis. At autopsy, the lungs were covered by clear gelatinous material and expanded by firm, variably discrete, tan-white nodules up to 8 cm diameter containing tan-white, viscous material. The tracheobronchial lymph nodes were firm and enlarged up to 6 × 4 × 3 cm; the thoracic aorta and carotid arteries were lined by hard, tan-white, mineralized intimal plaques. Histologic examination of lung revealed numerous 10–20 μm diameter yeasts with clear 1–2 μm thick double-contoured walls, central basophilic nuclei, and frequent broad-based budding, consistent with Blastomyces dermatitidis. DNA sequencing confirmed the diagnosis. B. dermatitidis should be considered in the differential diagnosis of pulmonary disease in llamas.

The potential of graphene-based nanoparticles (GNPs) has recently gained significant attention in biomedicine, especially in tissue engineering. In this study, we investigated the osteoinductive and osteoconductive effects of low oxygen content graphene (LOG) nanoparticles on adult mesenchymal stem cells (MSCs) in vitro and in vivo. We showed that adult goat MSCs were viable in the presence of 0.1 mg/mL LOG and retained their stem cell properties. A 3D scaffold made from agarose was used to encapsulate MSCs and LOG nanoparticles. Scanning electron microscopy demonstrated the cell morphology and adherence of MSCs to LOG in the 3D form. The LOG and MSCs in the 3D scaffold were xenogenically implanted into a rat unicortical tibial bone defect. The combination of MSCs and LOG nanoparticles resulted in improved active bone formation and increased mineralization. These results strengthen the applicability of LOG nanoparticles as an adjunct treatment for bone tissue engineering.

PURPOSE:The heparin-reactive, helical peptide p5 is an effective amyloid imaging agent in mice with systemic amyloidosis. Analogs of p5 with modified secondary structure characteristics exhibited altered binding to heparin, synthetic amyloid fibrils, and amyloid extracts in vitro. Herein, we further study the effects of peptide helicity and chirality on specific amyloid binding using a mouse model of systemic inflammation-associated (AA) amyloidosis.PROCEDURES:Peptides with disrupted helical structure [p5(coil) and p5(Pro3)], with an extended sheet conformation [p5(sheet)] or an all-D enantiomer [p5(D)], were chemically synthesized, radioiodinated, and their biodistribution studied in WT mice as well as transgenic animals with severe systemic AA amyloidosis. Peptide binding was assessed qualitatively by using small animal single-photon emission computed tomography/x-ray computed tomography imaging and microautoradiography and quantitatively using tissue counting.RESULTS:Peptides with reduced helical propensity, p5(coil) and p5(Pro3), exhibited significantly reduced binding to AA amyloid-laden organs. In contrast, peptide p5(D) was retained by non-amyloid-related ligands in the liver and kidneys of both WT and AA mice, but it also bound AA amyloid in the spleen. The p5(sheet) peptide specifically bound AA amyloid in vivo and was not retained by healthy tissues in WT animals.CONCLUSIONS:Modification of amyloid-targeting peptides using D-amino acids should be performed cautiously due to the introduction of unexpected secondary pharmacologic effects. Peptides that adopt a helical structure, to align charged amino acid side chains along one face, exhibit specific reactivity with amyloid; however, polybasic peptides with a propensity for β-sheet conformation are also amyloid-reactive and may yield a novel class of amyloid-targeting agents for imaging and therapy.

This retrospective project summarizes the types of neoplasms identified in Virginia opossums (Didelphis virginiana) presented to the University of Tennessee, College of Veterinary Medicine (UTCVM) postmortem service in 1989-2014 and serves as a review of the literature. Of the 85 Virginia opossums identified from the UTCVM case database, there were 17 diagnoses of neoplasia from 12 cases (14%). These cases included 8 females, 2 males, and 2 neutered males. All opossums with known ages (11 of 12) were >2 y old. Pulmonary tumors, specifically minimally invasive or lepidic-predominant adenocarcinomas, were the most common diagnosis and accounted for 53% (9 of 17) of the neoplasms. Additional tumors included acute myeloid leukemia with eosinophil maturation, hepatic hemangiosarcoma, sarcoma (unknown origin), squamous cell carcinoma, disseminated mast cell tumor, trichoblastoma, thyroid adenoma, and an osteoma. These findings serve as a reference for the types of spontaneous neoplasms in Virginia opossums; based on these findings, neoplasia should be considered as a differential in mature captive Virginia opossums.