Recurrent and convolutional neural networks for sequential multispectral optoacoustic tomography (MSOT) imaging

Multispectral optoacoustic tomography (MSOT) is a beneficial technique for diagnosing and analyzing biological samples since it provides meticulous details in anatomy and physiology. However, acquiring high through-plane resolution volumetric MSOT is time-consuming. Here, we propose a deep learning model based on hybrid recurrent and convolutional neural networks to generate sequential cross-sectional images for an MSOT system. This system provides three modalities (MSOT, ultrasound, and optoacoustic imaging of a specific exogenous contrast agent) in a single scan. This study used ICG-conjugated nanoworms particles (NWs-ICG) as the contrast agent. Instead of acquiring seven images with a step size of 0.1 mm, we can receive two images with a step size of 0.6 mm as input for the proposed deep learning model. The deep learning model can generate five other images with a step size of 0.1 mm between these two input images meaning we can reduce acquisition time by approximately 71%.

New K50R mutant mouse models reveal impaired hypusination of eif5a2 with alterations in cell metabolite landscape

The eukaryotic translation initiation factor 5A1 (eIF5A1) and 5A2 (eIF5A2) are important proteins in a variety of physiological and pathophysiological processes and their function has been linked to neurodevelopmental disorders, cancer, and viral infections. Here, we report two new genome-edited mouse models, generated using a CRISPR-Cas9 approach, in which the amino acid residue lysine 50 is replaced with arginine 50 (K50R) in eIF5A1 or in the closely related eIF5A2 protein. This mutation prevents the spermidine-dependent post-translational formation of hypusine, a unique lysine derivative that is necessary for activation of eIF5A1 and eIF5A2. Mouse brain lysates from homozygous eif5a2-K50R mutant mice (eif5a2K50R/K50R) confirmed the absence of hypusine formation of eIF5A2, and metabolomic analysis of primary mouse dermal fibroblasts revealed significant alterations in the metabolite landscape compared to controls including increased levels of tryptophan, kyrunenine, pyridoxine, nicotinamide adenine dinucleotide, riboflavin, flavin adenine dinucleotide, pantothenate, and coenzyme A. Further supported by new publicly available bioinformatics data, these new mouse models represent excellent in vivo models to study hypusine-dependent biological processes, hypusination-related disorders caused by eIF5A1 and eIF5A2 gene aberrations or mRNA expression dysregulation, as well as several major human cancer types and potential therapies.

Piscichuvirus-Associated Severe Meningoencephalomyelitis in Aquatic Turtles, United States, 2009-2021

Viruses from a new species of piscichuvirus were strongly associated with severe lymphocytic meningoencephalomyelitis in several free-ranging aquatic turtles from 3 coastal US states during 2009-2021. Sequencing identified 2 variants (freshwater turtle neural virus 1 [FTuNV1] and sea turtle neural virus 1 [STuNV1]) of the new piscichuvirus species in 3 turtles of 3 species. In situ hybridization localized viral mRNA to the inflamed region of the central nervous system in all 3 sequenced isolates and in 2 of 3 additional nonsequenced isolates. All 3 sequenced isolates phylogenetically clustered with other vertebrate chuvirids within the genus Piscichuvirus. FTuNV1 and STuNV1 shared ≈92% pairwise amino acid identity of the large protein, which narrowly places them within the same novel species. The in situ association of the piscichuviruses in 5 of 6 turtles (representing 3 genera) with lymphocytic meningoencephalomyelitis suggests that piscichuviruses are a likely cause of lymphocytic meningoencephalomyelitis in freshwater and marine turtles.

Super-resolution and segmentation deep learning for breast cancer histopathology image analysis

Traditionally, a high-performance microscope with a large numerical aperture is required to acquire high-resolution images. However, the images' size is typically tremendous. Therefore, they are not conveniently managed and transferred across a computer network or stored in a limited computer storage system. As a result, image compression is commonly used to reduce image size resulting in poor image resolution. Here, we demonstrate custom convolution neural networks (CNNs) for both super-resolution image enhancement from low-resolution images and characterization of both cells and nuclei from hematoxylin and eosin (H&E) stained breast cancer histopathological images by using a combination of generator and discriminator networks so-called super-resolution generative adversarial network-based on aggregated residual transformation (SRGAN-ResNeXt) to facilitate cancer diagnosis in low resource settings. The results provide high enhancement in image quality where the peak signal-to-noise ratio and structural similarity of our network results are over 30 dB and 0.93, respectively. The derived performance is superior to the results obtained from both the bicubic interpolation and the well-known SRGAN deep-learning methods. In addition, another custom CNN is used to perform image segmentation from the generated high-resolution breast cancer images derived with our model with an average Intersection over Union of 0.869 and an average dice similarity coefficient of 0.893 for the H&E image segmentation results. Finally, we propose the jointly trained SRGAN-ResNeXt and Inception U-net Models, which applied the weights from the individually trained SRGAN-ResNeXt and inception U-net models as the pre-trained weights for transfer learning. The jointly trained model's results are progressively improved and promising. We anticipate these custom CNNs can help resolve the inaccessibility of advanced microscopes or whole slide imaging (WSI) systems to acquire high-resolution images from low-performance microscopes located in remote-constraint settings.

Endometrial hyperplasia with loss of APC in a novel population of Lyz2-expressing mouse endometrial epithelial cells

Loss of heterozygosity and promoter hypermethylation of APC is frequently observed in human endometrial cancer, which is the most common gynecological cancer in the US, but its carcinogenic driver status in the endometrial epithelium has not been confirmed. We have identified a novel population of progenitor endometrial epithelial cells (EECs) in mice that express LysM and give rise to approximately 15% of all EECs in adult mice. Lysozyme M (LysM) is a glycoside hydrolase that is encoded by Lyz2 and functions to protect cells from bacteria as part of the innate immune system. Its expression has been shown in a subset of hematopoietic stem cells and in specialized lung and small intestinal epithelial cells. Conditional deletion of Apc in LysM+ EECs results in significantly more epithelial cells compared to wild type mice. At five months of age, the Apc  cKO mice have enlarged uterine horns with pathology that is consistent with endometrial hyperplasia with cystic endometrial glands, non-villous luminal papillae, and nuclear atypia. Nuclear accumulation of β-catenin and ERα, both of which are known to induce endometrial hyperplasia, was observed in the EECs of the Apc  cKO mice. These results confirm that loss of APC in EECs can result in a phenotype similar to endometrial hyperplasia.

Reproductive one health in primates

One Health is a collaborative trans-disciplinary approach to health; integrating human, animal, and environmental health. The focus is often on infection disease transmission and disease risk mitigation. However, One Health also includes the multidisciplinary and comparative approach to disease investigation and health of humans, animals, and the environment. One key aspect of environmental/ecosystem health is conservation, the maintenance of healthy, actively reproducing wildlife populations. Reproduction and reproductive health are an integral part of the One Health approach: the comparative aspects of reproduction can inform conservation policies or breeding strategies (in situ and ex situ) in addition to physiology and disease. Differences in reproductive strategies affect the impact poaching and habitat disruption might have on a given population, as well as ex situ breeding programs and the management of zoo and sanctuary populations. Much is known about chimpanzees, macaques, and marmosets as these are common animal models, but there is much that remains unknown regarding reproduction in many other primates. Examining the similarities and differences between and within taxonomic groups allows reasonable extrapolation for decision-making when there are knowledge gaps. For example: (1) knowing that a species has very low reproductive rates adds urgency to conservation policy for that region or species; (2) identifying species with short or absent lactation anestrus allows ex situ institutions to better plan contraception options for specific individuals or prepare for the immediate next pregnancy; (3) recognizing that progestin contraceptives are effective contraceptives, but may be associated with endometrial hyperplasia in some species (in Lemuridae but not great apes) better guides empirical contraceptive choice; (4) recognizing the variable endometriosis prevalence across taxa improves preventive medicine programs. A summary of anatomical variation, endocrinology, contraception, pathology, and diagnostics is provided to illustrate these features and aid in routine physical and postmortem examinations as well as primate management.

Survey of amyloidosis cases among different free-living wild and zoo animals

Amyloidosis comprises a range of protein-folding disorders characterised by a buildup of amyloid deposits in one or multiple organs. The pathogenesis and pathologic findings of amyloidosis can vary widely due to the nature of the precursor protein. In veterinary medicine, there are 10 proteins known to form amyloid deposits in various organs. This review aims to compare amyloidosis cases among different free-living wild and zoo animals focussing in part on the determination of the species particularly susceptible to the amyloid formation and specific prone-to-aggregate protein commonly involved. This review addresses the transmission of AA amyloidosis pertinent to institutions, such as zoos, housing multiple individuals and species in relatively close proximity. In addition, this review includes summarisation for definitive diagnosis of single or multiple cases of amyloidosis affecting free-living wild and zoo animals. Insights into the diversity, transmission, and pathogenesis of known amyloidogenic proteins and species prevalently affected may help to establish a preventive intervention and stimulate the discovery of new diagnostic and therapeutic strategies.

Atypical Brucella inopinata-Like Species in 2 Marine Toads

We describe the isolation of atypical Brucella inopinata–like species and unique clinicopathologic findings in 2 adult marine toads (Rhinella marina), including oophoritis in 1 toad. These findings represent a novel emerging disease in toads and a possible zoonotic pathogen.

Integrins mediate placental extracellular vesicle trafficking to lung and liver in vivo

Membrane-bound extracellular vesicles (EVs) mediate intercellular communication in all organisms, and those produced by placental mammals have become increasingly recognized as significant mediators of fetal-maternal communication. Here, we aimed to identify maternal cells targeted by placental EVs and elucidate the mechanisms by which they traffic to these cells. Exogenously administered pregnancy-associated EVs traffic specifically to the lung; further, placental EVs associate with lung interstitial macrophages and liver Kupffer cells in an integrin-dependent manner. Localization of EV to maternal lungs was confirmed in unmanipulated pregnancy using a transgenic reporter mouse model, which also provided in situ and in vitro evidence that fetally-derived EVs, rarely, may cause genetic alteration of maternal cells. These results provide for the first time direct in vivo evidence that placental EVs target maternal immune cells, and further, that EVs can alter cellular phenotype.

Avian coxiellosis in nine psittacine birds, one black-browed barbet, and one paradise tanager

Infection with a novel species of the genus Coxiella was first described in three Swainson's blue mountain rainbow lorikeets from a zoological collection, and days later in a group of seven other psittacine birds and a toucan. We provide an update on coxiellosis in nine additional psittacines, and two non-psittacines. Psittacines originated in New England, the mid Atlantic, the Midwest, the South, and the Northwest. Psittacines most commonly had lesions in the brain, spleen, liver, and lungs, consisting of meningoencephalitis, hepatosplenomegaly, and interstitial pneumonia. Lesions contained histiocytic infiltrate, with intracytoplasmic, Gimenez-positive coccobacilli. Transmission electron microscopy revealed bacteria with trilaminar cell walls, electron dense cores, and spore-like forms. PCR revealed homology to the organism in index cases. In addition, one black-browed barbet and one paradise tanager were found with systemic coxiellosis; sequencing identified the same pathogen. These are the second piciforme and the first passerine affected by this pathogen, indicating expanded infectivity and pathogenicity.RESEARCH HIGHLIGHTS Report of coxiellosis in nine psittacines; lesions often in brain, spleen, liver, lung.Second piciforme with coxiellosis, a black-browed barbet.First case of avian coxiellosis described in a passerine, a paradise tanager.

Pulmonary hyalinosis in captive sugar gliders ( Petaurus breviceps)

Pulmonary hyalinosis is an idiopathic, typically incidental lesion of old dogs, characterized by multifocal aggregates of epithelioid and multinucleate macrophages that surround periodic acid-Schiff (PAS)-positive hyaline material in airways. Lung lesions resembling pulmonary hyalinosis were observed in 6 captive adult sugar gliders ( Petaurus breviceps; 5 females and 1 male) in a retrospective review of 18 autopsied animals. Clinical signs for 3 of the sugar gliders included lethargy, tachypnea, and dyspnea. At autopsy, 5 of 6 animals had comorbid lesions that were the primary cause of death. Gross pulmonary lesions were characterized by mildly firm, discolored, vaguely nodular areas of parenchyma. Histologic examination of the lung revealed granulomatous inflammation with intracellular and extracellular amphophilic hyaline bodies within alveoli and airways. Hyaline bodies were positive for PAS and oil red O staining, blue via crystal violet staining, and displayed birefringence under polarized light, similar to findings in dogs with pulmonary hyalinosis.

Uterine Mast Cells and Immunoglobulin-E Antibody Responses During Clearance of Tritrichomonas foetus

We showed earlier that Tritrichomonas foetus-specific bovine immunoglobulin (Ig)G1 and IgA antibodies in uterine and vaginal secretions are correlated with clearance of this sexually transmitted infection. Eosinophils have been noted in previous studies of bovine trichomoniasis but the role of mast cells and IgE responses have not been reported. The hypothesis that IgE and mast cell degranulation play a role in clearance was tested in 25 virgin heifers inseminated experimentally and infected intravaginally with T. foetus strain D1 at estrus and cultured weekly. Groups were euthanatized at 3, 6, 9, or 12 weeks, when tissues were fixed and secretions were collected for culture and antibody analysis. Immunohistochemistry using a monoclonal antibody to a soluble lipophosphoglycan (LPG)-containing surface antigen (TF1.17) demonstrated antigen uptake by uterine epithelial cells. Lymphoid nodules were detected below antigen-positive epithelium. Little IgG2 antibody was detected but IgG1, IgA, IgM, and IgE T. foetus-specific antibodies increased in uterine secretions at weeks 6 and 9 after infection. This was inversely proportional to subepithelial mast cells numbers and most animals cleared the infection by the sampling time after the lowest mast cell count. Furthermore, soluble antigen was found in uterine epithelium above inductive sites (lymphoid nodules). Cross-linking of IgE on mast cells by antigen and perhaps LPG triggering appears to have resulted in degranulation. Released cytokines may account for production of predominantly Th2 (IgG1 and IgE) and IgA antibody responses, which are related to clearance of the infection.

Cystic Endometrial Hyperplasia in Elephants

Most captive female elephants are nulliparous and aged and many have endometrial disease, factors that may hinder fertility. This study characterized the pathologic features and demographic distribution of endometrial lesions from 27 captive Asian ( Elephas maximus) and 13 African elephants ( Loxodonta africanus), 12- to 57-years of age. The principal lesion was marked cystic and polypoid endometrial hyperplasia (CEH), present in 67% of Asian and 15% of African elephants ranging from 26 to 57 years. The lower prevalence in African elephants likely reflects their younger age range in this study. Fourteen of 15 affected elephants with breeding information were nulliparous. These results suggest that CEH and polyps are common in aged nulliparous elephants, and the severity of these lesions may impair fertility. These findings will be useful in the interpretation of ultrasonographic findings during reproductive examinations of potential breeding cows. Also, breeding programs should focus on younger animals.

In vitro flubendazole-induced damage to vital tissues in adult females of the filarial nematode Brugia malayi

The use of a microfilaricidal drug for the control of onchocerciasis and lymphatic filariasis necessitates prolonged yearly dosing. Prospects for elimination or eradication of these diseases would be enhanced by availability of a macrofilaricidal drug. Flubendazole (FLBZ), a benzimidazole anthelmintic, is an appealing candidate macrofilaricide. FLBZ has demonstrated profound and potent macrofilaricidal effects in a number of experimental filarial rodent models and one human trial. Unfortunately, FLBZ was deemed unsatisfactory for use in mass drug administration (MDA) campaigns due to its markedly limited oral bioavailability. However, a new formulation that provided sufficient bioavailability following oral administration could render FLBZ an effective treatment for onchocerciasis and LF. This study characterized the effects of FLBZ and its reduced metabolite (FLBZ-R) on filarial nematodes in vitro to determine the exposure profile which results in demonstrable damage. Adult female Brugia malayi were exposed to varying concentrations of FLBZ or FLBZ-R (100 nM–10 μM) for up to five days, after which worms were fixed for histology. Morphological damage following exposure to FLBZ was observed prominently in the hypodermis and developing embryos at concentrations as low as 100 nM following 24 h exposure. The results indicate that damage to tissues required for reproduction and survival can be achieved at pharmacologically relevant concentrations.

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Detrimental effects observed in tissues required for development and survival.

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Damage occurs at concentrations ≥100 nM.

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Hypodermal and embryonic tissues exhibited the most severe damage.

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Oocytes and early morula are the most affected embryonic tissues.

Chronic exposures to low levels of estradiol and their effects on the ovaries and reproductive hormones: Comparison with aging

Aging in female rats is characterized by a state called "constant estrous" in which rats are unable to ovulate, have polycystic ovaries and moderately elevated estrogen levels. We hypothesized that chronic exposure of young animals to low levels of E2 can produce reproductive changes similar to that seen in aging animals. Adult female rats were sham-implanted (control) or implanted with slow-release E2 (20 ng/day) pellets for 30, 60, or 90 days. Old constant estrous (OCE) rats were used for comparison. Estrous cyclicity was monitored periodically. At the end of treatment, animals were sacrificed, trunk blood was collected for hormone measurements and ovaries for immunohistochemistry. Young animals became acyclic with increasing duration of E2 exposure while OCE rats were in a state of acyclicity. Ovaries became increasingly more cystic with E2 exposure, and were comparable to OCE rats; however, there was a marked reduction in interstitial tissue with exogenous E2 treatment. Exogenous E2 also decreased Mullerian inhibiting substance expression, increased infiltration of macrophages without much impact on apoptosis in the ovaries. Serum testosterone levels decreased in E2-treated young animals, while it increased significantly in OCE rats. There was a marked reduction in LH but not FSH levels with E2 exposure in both young and old animals. These results indicate that even very low doses of E2 are capable of inducing aging-like changes in young animals.

Diagnostic value of transcervical endometrial biopsies in domestic dogs compared with full-thickness uterine sections

Transcervical endometrial biopsy is a useful tool for obtaining information about uterine health in some species. The clinical application of information gained from histopathological interpretations of endometrial biopsies in the bitch has not been validated. We hypothesized that transcervical endometrial biopsy samples would be as diagnostic as full-thickness uterine sections in identifying cystic endometrial hyperplasia (CEH), inflammation and periglandular fibrosis. Endometrial biopsies were obtained from 20 female adult dogs. Vaginal swabs, gross appearance of the vulva and vaginal tract, and serum progesterone values were used to determine the stage of the oestrous cycle at the time of sampling. The uteri were removed between 1 and 6 days after the biopsy procedure, and full-thickness sections were collected from each uterine horn and ovary and processed for histopathology. Two pathologists, blinded to the origin of each sample, compared full-thickness sections from the excised uteri to the biopsy samples collected via the transcervical technique. Pathologic features noted included: CEH, inflammation and periglandular fibrosis. Pathological diagnoses obtained from the biopsy sections were compared with those obtained from the full-thickness sections, as well as comparing diagnoses between the two pathologists, using McNemar's test. Of the 59 total biopsy samples obtained, 54 were considered diagnostic. All stages of the canine oestrous cycle were represented (anoestrus, proestrus, oestrus and dioestrus). Pyometra was not noted in any of the transcervical biopsy sections, but was noted in many of the full-thickness sections collected from dogs in dioestrus, suggesting either that biopsy is not a sensitive indicator of pyometra or that the procedure may induce pyometra in dioestrous dogs. Transcervical endometrial biopsy showed similar sensitivity as full-thickness sections in detecting CEH, inflammation and fibrosis. No differences in describing lesions were detected between pathologists.

Evaluation of hypoxia in a feline model of head and neck cancer using ⁶⁴Cu-ATSM positron emission tomography/computed tomography

Background

Human and feline head and neck squamous cell carcinoma (HNSCC) share histology, certain molecular features, as well as locally aggressive and highly recurrent clinical behavior. In human HNSCC, the presence of significant hypoxia within these tumors is considered an important factor in the development of a more aggressive phenotype and poor response to therapy. We hypothesized that feline head and neck tumors, particularly HNSCC, would exhibit hypoxia and that ⁶⁴Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) positron emission tomography/computed tomography (PET/CT) would permit detection of intratumoral hypoxia.

Methods

12 cats with measureable head and neck tumors were given ⁶⁴Cu-ATSM and iodinated contrast for PET/CT scan. The presence or absence of hypoxia was also assessed using an intratumoral fluorescent life-time probe to quantitate pO₂ and pimonidazole immunohistochemical staining in biopsy specimens. In two cats, intratumoral O₂ and ⁶⁴Cu-ATSM uptake was measured before and after treatment with anti-angiogenic agents to determine the effect of these agents on hypoxia.

Results

Eleven of twelve feline tumors demonstrated significant ⁶⁴Cu-ATSM uptake, regardless of malignant or benign etiology. The presence (and absence) of hypoxia was confirmed using the fluorescent O₂ detection probe in nine tumors, and using pimonidazole staining in three tumors. Squamous cell carcinomas (HNSCC) demonstrated the highest degree of hypoxia, with T_max/M ratios ranging from 4.3 to 21.8. Additional non-neoplastic tissues exhibited ⁶⁴Cu-ATSM uptake suggestive of hypoxia including reactive draining lymph nodes, non-malignant thyroid pathology, a tooth root abscess, and otitis media. In two cats with HNSCC that received anti-vascular agents, the pattern of ⁶⁴Cu-ATSM uptake was altered after treatment, demonstrating the potential of the feline model to study the modulation of tumor oxygenation.

Conclusion

Feline HNSCC serves as a clinically relevant model for the investigation of intratumoral hypoxia including its measurement, modulation and targeting.

The Effect of Environmental Storage Conditions on Bone Marrow Fat Determination in Three Species

Diagnostic laboratories are frequently required to assess the antemortem nutritional condition of deceased animals. The percentage of fat in the bone marrow is used to diagnose starvation because this fat depot is typically the last in the body to be depleted. Diagnosticians rely on measurement of bone marrow adipose content using fat solvent–extraction methods; however, the effects of tissue storage conditions before processing have not been fully assessed. The current study focuses on evaluating the effects of 3 storage conditions (refrigeration [4°C], freezing [–20°C], and ambient temperature [9.9–34.4°C]) on the percentage of fat in the bone marrow from 3 species. Equine, bovine, and canine humeri and femurs were removed within 24 hr of death from adult animals in adequate body condition and then stored as described for a minimum of 30–60 days. Bone marrow was harvested from these tissues at the time of necropsy and after 30–60 days. Percentage of fat was measured using an automated solvent extractor. Mean percentage of fat in the bone marrow in initial equine, bovine, and canine samples was 81.75%, 86.33%, and 59.96%, respectively. The results indicate that bovine and equine percentage of fat in bone marrow does not change after 30–60 days, regardless of the storage condition, whereas the fat content from canine tissues varies when stored at ambient temperatures. Results suggest that postmortem interval and environmental conditions of samples must be considered in the postmortem evaluation of bone marrow fat concentration in at least some species.

Abstract 439: Evaluation of hypoxia in a feline model of head and neck squamous cell carcinoma using 64Cu-ATSM positron emission tomography

Tumor hypoxia substantially impacts the prognosis of cancer patients by impairing the response to therapy and by promoting the acquisition of a malignant cellular phenotype. A variety human tumors exhibit hypoxia including head and neck squamous cell carcinoma (HNSCC) where it is considered a barrier to successful management of these patients. In the feline, HNSCC is a common and aggressive malignancy that shares morphologic, clinical and molecular features with human HNSCC. Therefore, feline HNSCC may serve as an informative model. To date, there are no data concerning the occurrence of hypoxia in feline HNSCC. We hypothesized that like its human counter part, feline HNSCC would demonstrate regions of intratumoral hypoxia and that hypoxia would be a feature of malignant rather than benign oral tumors. To test this hypothesis, cats with spontaneously occurring oral tumors (N=7) were administered 2 mCi 64Cu- diacetyl-bis(N4-methylthiosemicarbazone) (ATSM) IV 20 minutes prior to PET-CT scan (Discovery ST, GE Healthcare). Histologically, 4 cats had invasive squamous cell carcinoma, 1 had osteosarcoma and 2 had inflammatory lesions (1 polyp and 1 granuloma). All four squamous cell carcinomas and both inflammatory lesions demonstrated strong diffuse uptake of 64Cu within the tumor. Two cats with metastases to regional lymph nodes also demonstrated significant 64Cu uptake. Tumor hypoxia was confirmed by fluorescent lifetime probe measurements (Oxylab pO2), Oxford Optronix) in 4 cats and pimonidazole (HypoxyporbeTM-1, Hypoxyprobe Inc) uptake in biopsy samples in 4 cats. These data indicate that HNSCC in the cat exhibits significant, diffuse hypoxia. Hypoxia was also significant in inflammatory lesions and thus was not a marker of malignancy, but could indicate that inflammatory disease may provide a selective microenvironement to promote tumorigenesis in the cat. The feline model may provide an important tool for studying clinical methods to modulate hypoxia and to study the role of hypoxia on oral carcinogenesis. We are currently evaluating the effect of vascular modulating agents on feline HNSCC and intratumoral hypoxia as a means to optimize this therapy for combination with irradiation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 439.

A pregnant mouse model for bovine Tritrichomonas foetus infection

The economically important effects of Tritrichomonas foetus infection in cattle are abortion and infertility, yet there has not been an animal model to examine the parasite-host interactions during gestation. In this study, 5- and 7- to 8-week-old BALB/cAnNCr, BALB/cJ, and SCID/NCr mice on a BALB/c background were intravaginally infected with T. foetus. All BALB/cAnNCr and BALB/cJ mice, and 89% of SCID/NCr mice sustained infections for 13 weeks, if inoculated before 5 weeks of age. Infection rates were lower in all mouse strains inoculated at 7 weeks of age, although BALB/cAnNCr mice were significantly more susceptible than BALB/cJ or SCID/NCr mice. Vaginal bacterial flora did not account for the variation in mouse-strain susceptibility, although coagulase-negative staphylococci in vaginal flora were associated with failure of T. foetus to infect. As with infected cattle, T. foetus-specific vaginal immunoglobulin (Ig) G and IgA antibodies were elevated after infection. The number and viability of day-10 fetuses were reduced in mice infected at 5 weeks of age and bred 12 weeks after infection. Lesions in pregnant and nonpregnant infected mice, including suppurative and eosinophilic vaginitis; cervicitis; endometritis with distension of the uterine lumen; endometrial ulceration; and glandular ectasia, with neutrophils in the glandular lumen and loss of gland epithelium, were similar to those in cattle. The decidua and placenta were multifocally necrotic. Immunohistochemistry demonstrated trichomonads in vaginal folds and uterine glands, and adjacent to fetal tissues. In summary, experimentally infected BALB/cAnNCr mice showed many pathologic similarities to cattle and may serve as a model to study host-trichomonad interactions.

Ependymal cyst in a cynomolgus macaque (Macaca fascicularis)

BACKGROUND

A focal hypointense intracranial lesion was detected by magnetic resonance imaging in the right caudal occipital lobe of the cerebrum in an asymptomatic cynomolgus macaque (Macaca fascicularis).

RESULTS

Following euthanasia, gross evaluation of the lesion revealed a 1 cm diameter, wedge-shaped intracranial cavitation without apparent communication with the ventricles. Histologically, the lesion was lined by ciliated cuboidal to low columnar epithelium that showed immunopositivity for cytokeratin, S-100, and GFAP.

CONCLUSION

Based upon the gross, histologic, and immunohistochemical findings, this lesion was classified as an ependymal cyst. In the human patients, ependymal cysts are benign, non-infectious, non-inflammatory lesions of the central nervous system that are believed to originate from aberrant migration of ependymal cells during development. To our knowledge, this is the first report of an ependymal cyst in a non-rodent veterinary species and the first report of a benign intracranial cyst of any classification in a non-human primate.

The elephants of Zoba Gash Barka, Eritrea: part 4. Cholelithiasis in a wild African elephant (Loxodonta africana)

A 4.0-kg cholelith was found within the abdominal cavity of a dead wild African elephant (Loxodonta africana) in Eritrea. Analysis of this cholelith by histochemistry, electron microscopy, electrospray mass spectroscopy, and energy-dispersive x-ray spectroscopy revealed it was composed of bile alcohols but no calcium, bilirubin, or cholesterol. Bacteria were also found in the cholelith. Similar, but smaller, bile stones have been identified previously in other wild African elephants and an excavated mammoth (Mammuthus columbi). Choleliths have been reported only once in a captive Asian elephant (Elephas maximus). Elephants, along with hyraxes (Procavia capensis) and manatees (Trichechus manatus), are unique among mammals in producing only bile alcohols and no bile acids, which may predispose them to cholelithiasis, particularly in association with bacterial infection. Dietary factors may also play an important role in cholelith formation.

Corneal avascularity is due to soluble VEGF receptor-1

Corneal avascularity-the absence of blood vessels in the cornea-is required for optical clarity and optimal vision, and has led to the cornea being widely used for validating pro- and anti-angiogenic therapeutic strategies for many disorders. But the molecular underpinnings of the avascular phenotype have until now remained obscure and are all the more remarkable given the presence in the cornea of vascular endothelial growth factor (VEGF)-A, a potent stimulator of angiogenesis, and the proximity of the cornea to vascularized tissues. Here we show that the cornea expresses soluble VEGF receptor-1 (sVEGFR-1; also known as sflt-1) and that suppression of this endogenous VEGF-A trap by neutralizing antibodies, RNA interference or Cre-lox-mediated gene disruption abolishes corneal avascularity in mice. The spontaneously vascularized corneas of corn1 and Pax6+/- mice and Pax6+/- patients with aniridia are deficient in sflt-1, and recombinant sflt-1 administration restores corneal avascularity in corn1 and Pax6+/- mice. Manatees, the only known creatures uniformly to have vascularized corneas, do not express sflt-1, whereas the avascular corneas of dugongs, also members of the order Sirenia, elephants, the closest extant terrestrial phylogenetic relatives of manatees, and other marine mammals (dolphins and whales) contain sflt-1, indicating that it has a crucial, evolutionarily conserved role. The recognition that sflt-1 is essential for preserving the avascular ambit of the cornea can rationally guide its use as a platform for angiogenic modulators, supports its use in treating neovascular diseases, and might provide insight into the immunological privilege of the cornea.

Elephants and human color-blind deuteranopes have identical sets of visual pigments

Being the largest land mammals, elephants have very few natural enemies and are active during both day and night. Compared with those of diurnal and nocturnal animals, the eyes of elephants and other arrhythmic species, such as many ungulates and large carnivores, must function in both the bright light of day and dim light of night. Despite their fundamental importance, the roles of photosensitive molecules, visual pigments, in arrhythmic vision are not well understood. Here we report that elephants (Loxodonta africana and Elephas maximus) use RH1, SWS1, and LWS pigments, which are maximally sensitive to 496, 419, and 552 nm, respectively. These light sensitivities are virtually identical to those of certain "color-blind" people who lack MWS pigments, which are maximally sensitive to 530 nm. During the day, therefore, elephants seem to have the dichromatic color vision of deuteranopes. During the night, however, they are likely to use RH1 and SWS1 pigments and detect light at 420-490 nm.

Real-time polymerase chain reaction testing for the detection of Mycobacterium genavense and Mycobacterium avium complex species in avian samples

Diagnosis of avian mycobacteriosis, caused by Mycobacterium genavense or species belonging to the Mycobacterium avium complex (MAC), is problematic. Polymerase chain reaction (PCR) offers rapid and sensitive detection of minute quantities of DNA, and conventional protocols have been used for evaluating avian specimens. The recent development of real-time PCR offers several advantages over conventional PCR. In attempts to improve diagnosing avian mycobacteriosis, a real-time TaqMan PCR assay was developed targeting the 65-kD heat shock protein gene of M. genavense and MAC spp. Nineteen reference isolates, 16 clinical isolates, and 32 avian tissue samples were used to evaluate the assay. When sufficient amplicons were produced, the species of mycobacteria was determined by standard sequencing of TaqMan PCR products and compared with results from commercial mycobacteriology laboratories and/or standard sequencing of conventional PCR products. The TaqMan PCR detected DNA from reference isolates of M. genavense, MAC spp., and Mycobacterium tuberculosis complex spp. Of the clinical isolates, the TaqMan PCR detected DNA from 10 of 12 Mycobacterium avium avium isolates and two of three Mycobacterium avium intracellulare isolates. For the tissue samples, the TaqMan PCR amplified DNA in six of nine samples that were identified by sequencing of conventional PCR products and/or by commercial mycobacteriology laboratories as being MAC spp. positive and three of four samples that were positive for M. genavense. There was some disagreement between speciation results from the TaqMan PCR and those from commercial mycobacteriology laboratories or conventional PCR or both. This disagreement was suspected to be because of relatively small numbers of base pairs in the TaqMan PCR products. The TaqMan PCR may provide a useful tool for evaluating clinical samples for DNA from mycobacteria species that most commonly infect birds; however, further refinement is needed in order to improve sensitivity and provide more accurate speciation.

Ultrasonographic and histologic evaluation of medial and middle patellar ligaments in exercised horses following injection with ethanolamine oleate and 2% iodine in almond oil

OBJECTIVE

To describe the ultrasonographic and quantitative histologic effect of injecting 2% iodine in almond oil (IAO) and ethanolamine oleate (EO) in the medial and middle patellar ligaments of horses and to determine whether a difference in response exists between IAO and EO treatment.

ANIMALS

10 healthy horses.

PROCEDURE

In 5 horses, the medial and middle patellar ligaments of 1 limb were injected with EO, whereas IAO was injected in the medial and middle patellar ligaments of another 5 horses. Ultrasonographic evaluation was performed on the experimental and control limb before injection of IAO and EO and prior to euthanasia to determine cross-sectional area and evaluate fiber pattern. The patellar ligaments were harvested 2 weeks after injection and examined histologically to evaluate the inflammatory response, fibroplasia, and chondroid metaplasia.

RESULTS

Injection of the patellar ligaments with IAO resulted in a greater increase in cross-sectional area on ultrasonography than EO. Both agents caused a decrease in echogenicity of the ligament. Histologically, significantly greater infiltration of inflammatory cells and fibroplasia developed after injection with IAO, compared with EO. Both agents resulted in significantly greater fibroplasia relative to control specimens.

CONCLUSIONS AND CLINICAL RELEVANCE

Injection of the medial and middle patellar ligaments with IAO induces more severe inflammation and fibroplasia than EO. Maturation of the inflammatory and fibrous response may contribute to resolution or attenuation of upward fixation of the patella by subsequent stiffening of the ligaments.

Zinc toxicosis in a captive striped hyena (Hyaena hyaena)

An 11-yr-old captive-born female striped hyena (Hyaena hyaena) acutely developed lameness and swelling of the left front foot with anorexia, depression, and lethargy. Hematologic evaluation revealed regenerative anemia, azotemia, and other mild serum electrolyte and mineral abnormalities. Twenty radiographically visible coins and 10 coin fragments were removed by laparotomy and gastrotomy following unsuccessful medical therapy. The animal died during anesthetic recovery. Zinc serum levels were 41.0 ppm at first presentation and 36.0 ppm at the time of surgery, compared with concentrations of 1.78 ppm and 2.82 ppm for serum taken from this female and a male hyena 3 mo previously. Zinc toxicosis was diagnosed based on the similarity of clinical signs to those described in dogs, presence in the stomach of pennies minted after 1982 (when the zinc content of U.S. pennies was increased substantially), necropsy findings, and elevated serum and liver zinc values. The case highlights the risk posed by penny ingestion for subsequent zinc toxicosis in captive omnivores.