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In partial onset epilepsy, seizures arise focally in the brain and often propagate. Patients frequently become refractory to medical management, leaving neurosurgery, which can cause neurologic deficits, as a primary treatment. In the cortex, focal seizures spread through horizontal connections in layers II/III, suggesting that severing these connections can block seizures while preserving function. Focal neocortical epilepsy is induced in mice, sub‐surface cuts are created surrounding the seizure focus using tightly‐focused femtosecond laser pulses, and electrophysiological recordings are acquired at multiple locations for 3–12 months. Cuts reduced seizure frequency in most animals by 87%, and only 5% of remaining seizures propagated to the distant electrodes, compared to 80% in control animals. These cuts produced a modest decrease in cortical blood flow that recovered and left a ≈20‐µm wide scar with minimal collateral damage. When placed over the motor cortex, cuts do not cause notable deficits in a skilled reaching task, suggesting they hold promise as a novel neurosurgical approach for intractable focal cortical epilepsy. [ABSTRACT FROM AUTHOR]

Objective: To determine if a single brain biopsy utilizing a freeze-core needle harvest system Cassi II under ultrasound guidance provides a diagnostic sample; to evaluate the technique's efficacy in procuring diagnostic samples in comparison with "open" surgical biopsies; and to describe intraoperative complications associated with the technique. Study design: Experimental clinical study. Animals: Seventeen dogs and four cats with magnetic resonance imaging (MRI) diagnoses of readily surgically accessible intracranial masses. Methods: Immediately prior to surgical biopsy (SB), freeze-core biopsy (FCB) sample was obtained from each patient under ultrasound guidance. Results: Histopathology results from single FCB samples were found to be in 100% agreement with the SB samples. Freezing artifact was minimal and did not interfere with histopathologic interpretation. There were no intraoperative complications specifically attributable to the use of the FCB system. Conclusion: Based on the results of this small experimental study, the FCB system is expected to safely yield diagnostic quality intracranial masses biopsy specimens. Clinical significance: This system has the potential of obtaining diagnostic biopsies of more deeply seated brain lesions (i.e., intra-axial tumors considered inaccessible or with large risks/difficulties by standard surgical means) which would provide a definitive diagnosis to guide appropriate therapy. [ABSTRACT FROM AUTHOR]

Summary: This is the first known case report of encephalitic listeriosis in a donkey (Equus asinus). A 5‐day‐old female donkey foal presented for fever, progressive weakness and loss of suckle reflex. Upon arrival, its vital parameters were normal, but the foal was collapsed. It had horizontal nystagmus, front limb paddling, minimal response to stimuli, prolapse of the left third eyelid and curling the neck to the left when in sternal recumbency. Samples collected for diagnostic evaluation included blood and cerebral spinal fluid. The cerebrospinal fluid (CSF) showed a pleocytosis consisting mainly of nondegenerative neutrophils and a normal protein concentration. Bacteria were not seen on Gram stain. After 24 h of treatment with intravenous fluids, anti‐inflammatories, antibiotics, nasogastric feedings of the dam's milk and supplemental nasal oxygen, little improvement was observed and the owners elected to euthanise the foal. Post‐mortem examination revealed multifocal, irregularly distributed hepatic necrosis and multifocal lymphohistiocytic encephalitis. Listeria monocytogenes was isolated from a section of brainstem. [ABSTRACT FROM AUTHOR]

Objective: To (1) describe exposure history, clinical signs, treatment, and diagnostic findings in 4 dogs following ingestion of tamarinds, and in 2 dogs following ingestion of cream of tartar, and (2) discuss tartaric acid, the commondenominator, as the proposed toxic principle in tamarinds and grapes. Series Summary: Reports in which dogs developed acute kidney injury following ingestion of cream of tartar or tamarinds were identified from the ASPCA Animal Poison Control Center electronic database. In these cases, decontamination was not performed, and treatments were delayed. Despite IV fluids and symptomatic and supportive care, 2 of the dogs became anuric and 1 became oliguric. Four dogs were euthanized, and the outcome is unknown for 2 of the dogs. Necropsies were performed on 3 of the dogs. Clinical signs, laboratory findings, and histopathologic lesions were similar to those reported in grape and raisin toxicosis. New or Unique Information Provided: Acute kidney injury may develop following ingestion of cream of tartar or tamarinds in dogs. Connecting these reports with findings in grape and raisin toxicosis and the sensitivity to tartaric acid in dogs, tartaric acid is identified as the likely toxic component in grapes and tamarinds. [ABSTRACT FROM AUTHOR]

Documented natural infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in exotic and companion animals following human exposures are uncommon. Those documented in animals are typically mild and self-limiting, and infected animals have only infrequently died or been euthanized. Through a coordinated One Health initiative, necropsies were conducted on 5 animals from different premises that were exposed to humans with laboratory-confirmed SARS-CoV-2 infection. The combination of epidemiologic evidence of exposure and confirmatory real-time reverse transcriptase-polymerase chain reaction testing confirmed infection in 3 cats and a tiger. A dog was a suspect case based on epidemiologic evidence of exposure but tested negative for SARS-CoV-2. Four animals had respiratory clinical signs that developed 2 to 12 days after exposure. The dog had bronchointerstitial pneumonia and the tiger had bronchopneumonia; both had syncytial-like cells with no detection of SARS-CoV-2. Individual findings in the 3 cats included metastatic mammary carcinoma, congenital renal disease, and myocardial disease. Based on the necropsy findings and a standardized algorithm, SARS-CoV-2 infection was not considered the cause of death in any of the cases. Continued surveillance and necropsy examination of animals with fatal outcomes will further our understanding of natural SARS-CoV-2 infection in animals and the potential role of the virus in development of lesions. [ABSTRACT FROM AUTHOR]

There is a growing appreciation for the idea that bacterial utilization of host-derived lipids, including cholesterol, supports Mycobacterium tuberculosis (Mtb) pathogenesis. This has generated interest in identifying novel antibiotics that can disrupt cholesterol utilization by Mtb in vivo. Here we identify a novel small molecule agonist (V-59) of the Mtb adenylyl cyclase Rv1625c, which stimulates 3', 5'-cyclic adenosine monophosphate (cAMP) synthesis and inhibits cholesterol utilization by Mtb. Similarly, using a complementary genetic approach that induces bacterial cAMP synthesis independent of Rv1625c, we demonstrate that inducing cAMP synthesis is sufficient to inhibit cholesterol utilization in Mtb. Although the physiological roles of individual adenylyl cyclase enzymes in Mtb are largely unknown, here we demonstrate that the transmembrane region of Rv1625c is required during cholesterol metabolism. Finally, the pharmacokinetic properties of Rv1625c agonists have been optimized, producing an orally-available Rv1625c agonist that impairs Mtb pathogenesis in infected mice. Collectively, this work demonstrates a role for Rv1625c and cAMP signaling in controlling cholesterol metabolism in Mtb and establishes that cAMP signaling can be pharmacologically manipulated for the development of new antibiotic strategies. Author summary: The recalcitrance of Mycobacterium tuberculosis (Mtb) to conventional antibiotics has created a need to identify novel pharmacological mechanisms to inhibit Mtb pathogenesis. There is a growing understanding of the metabolic adaptations Mtb adopts during infection to support its survival and pathogenesis. This has generated interest in identifying small molecule compounds that effectively inhibit these in vivo metabolic adaptations, while overcoming challenges like poor pharmacokinetic properties or redundancy in target pathways. The Mtb cholesterol utilization pathway has repeatedly been speculated to be a desirable antibiotic target, but compounds that successfully inhibit this complex pathway and are suitable for use in vivo are lacking. Here, we establish that stimulating cAMP synthesis in Mtb is a mechanism that is sufficient to block cholesterol utilization by the bacterium, preventing the release of key metabolic intermediates that are derived from breakdown of the cholesterol molecule. This work also identifies small molecule agonists of the Mtb adenylyl cyclase Rv1625c that have promising pharmacological properties and are suitable for use during in vivo studies. These Rv1625c agonists increase cAMP synthesis, inhibit cholesterol utilization by Mtb, and disrupt Mtb pathogenesis in mouse models of chronic infection. [ABSTRACT FROM AUTHOR]

A retrospective study of guinea pigs submitted for necropsy revealed intracytoplasmic inclusions in the cardiomyocytes of 26 of 30 animals. The inclusions were found with approximately the same frequency in male and female guinea pigs and were slightly more common in older animals. In most cases, the animals did not have clinical signs or necropsy findings suggestive of heart failure, and the cause of death or reason for euthanasia was attributed to concurrent disease processes. However, the 4 guinea pigs with the highest inclusion body burden all had pulmonary edema, sometimes with intra-alveolar hemosiderin-laden macrophages, suggestive of heart failure. The inclusions were found in both the left and right ventricular myocardium, mainly in the papillary muscles, but were most common in the right ventricular free wall. No inclusions were detected in the atrial myocardium or in skeletal muscle. The inclusions did not stain with Congo red or periodic acid–Schiff. Electron microscopy revealed dense aggregates of disorganized myofilaments and microtubules that displaced and compressed the adjacent organelles. By immunohistochemistry, there was some scattered immunoreactivity for desmin and actin at the periphery of the inclusions and punctate actin reactivity within the aggregates. The inclusions did not react with antibodies to ubiquitin or cardiac myosin, but were variably reactive for alpha B crystallin, a small heat shock chaperone protein. The inclusions were interpreted as evidence of impaired proteostasis. [ABSTRACT FROM AUTHOR]

Interleukin-2 (IL-2) inducible T-cell kinase (ITK) is a non-receptor tyrosine kinase highly expressed in T-cell lineages and regulates multiple aspects of T-cell development and function, mainly through its function downstream of the T-cell receptor. Itk deficiency can lead to CD4 lymphopenia and Epstein-Bar virus (EBV)-associated lymphoproliferation and recurrent pulmonary infections in humans. However, the role of the ITK signaling pathway in pulmonary responses in active tuberculosis due to Mtb infection is not known. We show here that human lungs with active tuberculosis exhibit altered T-cell receptor/ITK signaling and that Itk deficiency impaired early protection against Mtb in mice, accompanied by defective development of IL-17A-producing γδ T cells in the lungs. These findings have important implications of human genetics associated with susceptibility to Mtb due to altered immune responses and molecular signals modulating host immunity that controls Mtb activity. Enhancing ITK signaling pathways may be an alternative strategy to target Mtb infection, especially in cases with highly virulent strains in which IL-17A plays an essential protective role. [ABSTRACT FROM AUTHOR]

Background: Cancer is a significant health threat in cats. Chemoresistance is prevalent in solid tumors. The ionophore salinomycin has anti-cancer properties and may work synergistically with chemotherapeutics. The purpose of our study was to determine if salinomycin could decrease cancer cell viability when combined with doxorubicin in feline sarcoma and carcinoma cells. Results: We established two new feline injection-site sarcoma cell lines, B4 and C10, and confirmed their tumorigenic potential in athymic nude mice. B4 was more resistant to doxorubicin than C10. Dose-dependent effects were not observed until 92 μM in B4 cells (p = 0.0006) vs. 9.2 μM (p = 0.0004) in C10 cells. Dose-dependent effects of salinomycin were observed at 15 μM in B4 cells (p = 0.025) and at 10 μM in C10 cells (p = 0.020). Doxorubicin plus 5 μM salinomycin decreased viability of B4 cells compared to either agent alone, but only at supra-pharmacological doxorubicin concentrations. However, doxorubicin plus 5 μM salinomycin decreased viability of C10 cells compared to either agent alone at doxorubicin concentrations that can be achieved in vivo (1.84 and 4.6 μM, p < 0.004). In SCCF1 cells, dose-dependent effects of doxorubicin and salinomycin were observed at 9.2 (p = 0.036) and 2.5 (p = 0.0049) μM, respectively. When doxorubicin was combined with either 1, 2.5, or 5 μM of salinomycin in SCCF1 cells, dose-dependent effects of doxorubicin were observed at 9.2 (p = 0.0021), 4.6 (p = 0.0042), and 1.84 (p = 0.0021) μM, respectively. Combination index calculations for doxorubicin plus 2.5 and 5 μM salinomycin in SCCF1 cells were 0.4 and 0.6, respectively. Conclusions: We have developed two new feline sarcoma cell lines that can be used to study chemoresistance. We observed that salinomycin may potentiate (C10 cells) or work synergistically (SCCF1 cells) with doxorubicin in certain feline cancer cells. Further research is indicated to understand the mechanism of action of salinomycin in feline cancer cells as well as potential tolerability and toxicity in normal feline tissues. [ABSTRACT FROM AUTHOR]

Carcinosarcomas are biphasic malignant tumors composed of 2 distinct neoplastic cell populations, epithelial cells and mesenchymal cells. A 13-y-old, female, mixed-breed goat was presented with a 1-wk history of anuria and lethargy. Transabdominal ultrasonography showed an irregular and heterogeneous structure in the region of the bladder and uterus and changes in the echogenicity of both kidneys. Given the poor prognosis, euthanasia was elected. Autopsy revealed a large mass within the uterine cervix and confirmed the changes in the urinary tract. Histopathology and immunohistochemistry revealed a mixed, anti-cytokeratin AE1/AE3–positive epithelial, and vimentin-positive mesenchymal neoplasm consistent with a homologous carcinosarcoma, also called malignant mixed Müllerian tumor, with areas of double-labeling. We highlight the complexity of the diagnosis of uterine neoplasms in domestic animals and in goats in particular. [ABSTRACT FROM AUTHOR]

In vivo micro-computed tomography (CT) imaging allows longitudinal studies of pulmonary neoplasms in genetically engineered mouse models. Respiratory gating increases the accuracy of lung tumor measurements but lengthens anesthesia time in animals that may be at increased risk for complications. We hypothesized that semiautomated, volumetric, and linear tumor measurements performed in micro-CT images from non-gated scans would have correlation with histological findings. Primary lung tumors were induced in eight FVB mice with two transgenes (FVB/N-Tg(tetO-Kras2)12Hev/J; FVB.Cg-Tg(Scgb1a1-rtTA)1Jaw/J). Non-gated micro-CT scans were performed and the lungs were subsequently harvested. In the acquired micro-CT scans, measurements of all identified tumors were determined using the following methods: semiautomated three-dimensional (3D) volume, ellipsoid volume, Response Evaluation Criteria in Solid Tumors (RECIST; sum of largest axial (i.e., transverse) diameter from five tumors), sum of largest axial diameters from all tumors (modified RECIST), and average axial diameter. For histological analysis, all five lung lobes were analyzed and the tumor area was summed from measurements made on five histological sections that were 300 µm apart from each other (covering a total depth of 1200 µm). All micro-CT measurement methods had very strong correlation with histological tumor burden (Pearson’s correlation coefficient, 0.87 (p = 0.0053) −0.98 (p < 0.0001)). The only methods found to have different correlations were the semiautomated 3D method and the RECIST method (Williams’ test for dependent overlapping correlations, p = 0.013). Our results suggest quantification of lung tumor burden from non-gated micro-CT imaging will reflect histological differences between mice and can therefore be used for between-group comparisons or when concerns about systemic health of research animals may limit lengthy anesthetic procedures. [ABSTRACT FROM AUTHOR]

A 12‐hours‐old Paint filly was examined because of weakness and dull mentation after birth. Despite IV administered dextrose, the foal remained persistently hypoglycemic with increase in serum activity of muscle and liver enzymes. A postmortem diagnosis of lipid myopathy most similar to multiple acyl‐CoA dehydrogenase deficiency (MADD) was confirmed by findings of myofiber lipid accumulation, elevated urine organic acids, and serum free acylcarnitines with respect to control foals. This report details a case of equine neonatal lipid storage myopathy with many biochemical characteristics of MADD. Lipid storage myopathies should be included as a differential diagnosis in foals with persistent weakness and hypoglycemia. [ABSTRACT FROM AUTHOR]

Testicular germ cell tumors (TGCTs) are among the most responsive solid cancers to conventional chemotherapy. To elucidate the underlying mechanisms, we developed a mouse TGCT model featuring germ cell-specific Kras activation and Pten inactivation. The resulting mice developed malignant, metastatic TGCTs composed of teratoma and embryonal carcinoma, the latter of which exhibited stem cell characteristics, including expression of the pluripotency factor OCT4. Consistent with epidemiological data linking human testicular cancer risk to in utero exposures, embryonic germ cells were susceptible to malignant transformation, whereas adult germ cells underwent apoptosis in response to the same oncogenic events. Treatment of tumor-bearing mice with genotoxic chemotherapy not only prolonged survival and reduced tumor size but also selectively eliminated the OCT4-positive cancer stem cells. We conclude that the chemosensitivity of TGCTs derives from the sensitivity of their cancer stem cells to DNA-damaging chemotherapy. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Necrotizing meningoencephalitis (NME) affects toy and small breed dogs causing progressive, often fatal, inflammation and necrosis in the brain. Genetic risk loci for NME previously were identified in pug dogs, particularly associated with the dog leukocyte antigen (DLA) class II complex on chromosome 12, but have not been investigated in other susceptible breeds. We sought to evaluate Maltese and Chihuahua dogs, in addition to pug dogs, to identify novel or shared genetic risk factors for NME development. Genome-wide association testing of single nucleotide polymorphisms (SNPs) in Maltese dogs with NME identified 2 regions of genome-wide significance on chromosomes 4 (chr4:74522353T>A, p = 8.1×10−7) and 15 (chr15:53338796A>G, p = 1.5×10−7). Haplotype analysis and fine-mapping suggests that ILR7 and FBXW7, respectively, both important for regulation of immune system function, could be the underlying associated genes. Further evaluation of these regions and the previously identified DLA II locus across all three breeds, revealed an enrichment of nominal significant SNPs associated with chromosome 15 in pug dogs and DLA II in Maltese and Chihuahua dogs. Meta-analysis confirmed effect sizes the same direction in all three breeds for both the chromosome 15 and DLA II loci (p = 8.6×10–11 and p = 2.5×10−7, respectively). This suggests a shared genetic background exists between all breeds and confers susceptibility to NME, but effect sizes might be different among breeds. In conclusion, we identified the first genetic risk factors for NME development in the Maltese, chromosome 4 and chromosome 15, and provide evidence for a shared genetic risk between breeds associated with chromosome 15 and DLA II. Last, DLA II and IL7R both have been implicated in human inflammatory diseases of the central nervous system such as multiple sclerosis, suggesting that similar pharmacotherapeutic targets across species should be investigated. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the in vitro immunogenic and immunomodulatory properties of induced pluripotent stem cells (iPSCs) compared with bone marrow-derived mesenchymal stromal cells (MSCs). Materials & methods: Mouse embryonic fibroblasts (MEFs) were isolated from C3HeB/FeJ and C57BL/6J mice, and reprogrammed to generate iPSCs. Mixed leukocyte reactions were performed using MHC-matched and -mismatched responder leukocytes and stimulator leukocytes, iPSCs or MSCs. To assess immunogenic potential, iPSCs and MSCs were used as stimulator cells for responder leukocytes. To assess immunomodulatory properties, iPSCs and MSCs were cultured in the presence of stimulator and responder leukocytes. MEFs were used as a control. Results: iPSCs had similar immunogenic properties but more potent immunomodulatory effects than MSCs. Co-culture of MHC-mismatched leukocytes with MHC-matched iPSCs resulted in significantly less responder T-cell proliferation than observed for MHC-mismatched leukocytes alone and at more responder leukocyte concentrations than with MSCs. In addition, MHC-mismatched iPSCs significantly reduced responder T-cell proliferation when co-cultured with MHC-mismatched leukocytes, while MHC-mismatched MSCs did not. Conclusion: These results provide important information when considering the use of iPSCs in place of MSCs in both regenerative and transplantation medicine. [ABSTRACT FROM AUTHOR]

Genome maintenance in germ cells is critical for fertility and the stable propagation of species. While mechanisms of meiotic DNA repair and chromosome behavior are well-characterized, the same is not true for primordial germ cells (PGCs), which arise and propagate during very early stages of mammalian development. Fanconi anemia (FA), a genomic instability syndrome that includes hypogonadism and testicular failure phenotypes, is caused by mutations in genes encoding a complex of proteins involved in repair of DNA lesions associated with DNA replication. The signaling mechanisms underlying hypogonadism and testicular failure in FA patients or mouse models are unknown. We conducted genetic studies to show that hypogonadism of Fancm mutant mice is a result of reduced proliferation, but not apoptosis, of PGCs, resulting in reduced germ cells in neonates of both sexes. Progressive loss of germ cells in adult males also occurs, overlaid with an elevated level of meiotic DNA damage. Genetic studies indicated that ATM-p53-p21 signaling is partially responsible for the germ cell deficiency. [ABSTRACT FROM AUTHOR]

The use of engineered nanoparticles in food and pharmaceuticals is expected to increase, but the impact of chronic oral exposure to nanoparticles on human health remains unknown. Here, we show that chronic and acute oral exposure to polystyrene nanoparticles can influence iron uptake and iron transport in an in vitro model of the intestinal epithelium and an in vivo chicken intestinal loop model. Intestinal cells that are exposed to high doses of nanoparticles showed increased iron transport due to nanoparticle disruption of the cell membrane. Chickens acutely exposed to carboxylated particles (50 nm in diameter) had a lower iron absorption than unexposed or chronically exposed birds. Chronic exposure caused remodelling of the intestinal villi, which increased the surface area available for iron absorption. The agreement between the in vitro and in vivo results suggests that our in vitro intestinal epithelium model is potentially useful for toxicology studies. [ABSTRACT FROM AUTHOR]

Introduction: The influence of genetic background on the ability to generate induced pluripotent stem cells (iPSCs) has the potential to impact future applications, but has yet to be examined in detail. The purpose of this study was to determine if genetic background affects the efficiency of generating iPSCs during early reprograming as well as the pluripotent stability of the iPSCs during later stages of reprograming. Methods: Mouse embryonic fibroblasts (MEFs) were isolated from six strains of mice (NON/LtJ; C57BL/6J; DBA/2J; BALB/cJ; 129S1/SvlmJ; CAST/EiJ) that were selected based on genetic diversity and differences in ability to produce embryonic stem cell (ESC) lines. MEFs were reprogramed via doxycycline-inducible lentiviral transduction of murine Oct4, Klf4, Sox2, and c-Myc. Differences in efficiency to generate iPSCs were assessed by comparing the total number of colonies, the percentage of colonies positive for alkaline phosphatase staining and the percentage of cells positive for SSEA1. iPSC colonies were expanded to establish doxycycline-independent cell lines whose pluripotency was then evaluated via ability to form teratomas in NOD.CB17-Prkdcscid/J mice. Proliferation of non-transduced parent MEFs from each strain was also examined over ten days under conditions that simulated reprograming. Results: NON/LtJ and CAST/EiJ strains were more efficient than other strains in generating iPSCs for all parameters measured and parent MEFs from these strains were more proliferative than those from other strains. Doxycycline-independent iPSC lines were established using standard conditions for all strains except BALB/cJ, which required a higher concentration (5x) of leukemia inhibitory factor (LIF). iPSCs from all strains were capable of producing teratomas in NOD.CB17-Prkdcscid/J mice. Conclusions: The results of this study suggest that genetic background does affect iPSC generation and pluripotent stability. In addition, our results demonstrate that strain differences in efficiency to generate iPSCs during the early stages of reprograming are correlated with those observed in proliferation of parent MEFs. These findings have important implications both for future iPSC applications as well as for future investigation into determining the genes responsible for reprograming efficiency and stability. [ABSTRACT FROM AUTHOR]

During computed tomography ( CT), the appearance of disease involving the pulmonary acinus may be described using terms such as atelectasis, ground-glass opacity, or consolidation. These CT signs, however, have not been correlated with histologic findings in canine pulmonary disease. To facilitate interpretation of lung diseases by CT signs, our goals were to review the morphologic organization of the lung and evaluate the medical records of four dogs with different types of pulmonary acinar disease. Anatomic review focused on understanding the pulmonary acinus and the secondary pulmonary lobule; the secondary pulmonary lobule is a fundamental unit for interpretation in people. All dogs had similar CT findings of fully expanded lungs with increased attenuation and partial-to-complete obscuring of the pulmonary blood vessels. Histologic findings varied between dogs and included partial-to-complete filling of airspaces with cells or fluid, interstitial thickening, increased capillary blood volume, or a combination of these findings. Final diagnoses were hemorrhagic pneumonia, bronchiolar carcinoma, metastatic mammary adenocarcinoma, and pulmonary edema. In summary, the morphologic organization of the lungs is complex and has implications for diagnostic interpretation needing further evaluation in dogs. In this study, increased lung attenuation during CT due to disease localized to the pulmonary acini was due to the displacement of air from the lungs and not to the microscopic distribution of lesions within the pulmonary acinus. Imaging descriptors that classify diseases according to structures larger than the pulmonary acini, for example, regions of the secondary pulmonary lobule or larger, may be appropriate for dogs. [ABSTRACT FROM AUTHOR]

Effective DNA replication is critical to the health and reproductive success of organisms. The six MCM2-7 proteins, which form the replicative helicase, are essential for high-fidelity replication of the genome. Many eukaryotes have a divergent paralog, MCM9, that was reported to be essential for loading MCM2-7 onto replication origins in the Xenopus oocyte extract system. To address the in vivo role of mammalian MCM9, we created and analyzed the phenotypes of mice with various mutations in Mcm9 and an intronic DNA replication-related gene Asf1a. Ablation of Mcm9 was compatible with cell proliferation and mouse viability, showing that it is nonessential for MCM2-7 loading or DNA replication. Mcm9 mutants underwent p53-independent embryonic germ-cell depletion in both sexes, with males also exhibiting defective spermatogonial stem-cell renewal. MCM9-deficient cells had elevated genomic instability and defective cell cycle reentry following replication stress, and mutant animals were prone to sex-specific cancers, most notably hepatocellular carcinoma in males. The phenotypes of mutant mice and cells suggest that MCM9 evolved a specialized but nonessential role in DNA replication or replication-linked quality-control mechanisms that are especially important for germ-line stem cells, and also for tumor suppression and genome maintenance in the soma. [ABSTRACT FROM AUTHOR]

Background: Shaker codes for a Drosophila voltage-dependent potassium channel. Flies carrying Shaker null or hypomorphic mutations sleep 3-4 h/day instead of 8-14 h/day as their wild-type siblings do. Shaker-like channels are conserved across species but it is unknown whether they affect sleep in mammals. To address this issue, we studied sleep in Kcna2 knockout (KO) mice. Kcna2 codes for Kv1.2, the alpha subunit of a Shaker-like voltage-dependent potassium channel with high expression in the mammalian thalamocortical system. Results: Continuous (24 h) electroencephalograph (EEG), electromyogram (EMG), and video recordings were used to measure sleep and waking in Kcna2 KO, heterozygous (HZ) and wild-type (WT) pups (P17) and HZ and WT adult mice (P67). Sleep stages were scored visually based on 4- s epochs. EEG power spectra (0-20 Hz) were calculated on consecutive 4-s epochs. KO pups die by P28 due to generalized seizures. At P17 seizures are either absent or very rare in KO pups (< 1% of the 24-h recording time), and abnormal EEG activity is only present during the seizure. KO pups have significantly less non-rapid eye movement (NREM) sleep (-23%) and significantly more waking (+21%) than HZ and WT siblings with no change in rapid eye movement (REM) sleep time. The decrease in NREM sleep is due to an increase in the number of waking episodes, with no change in number or duration of sleep episodes. Sleep patterns, daily amounts of sleep and waking, and the response to 6 h sleep deprivation are similar in HZ and WT adult mice. Conclusion: Kv1.2, a mammalian homologue of Shaker, regulates neuronal excitability and affects NREM sleep. [ABSTRACT FROM AUTHOR]

Sleep intensity is regulated by the duration of previous wakefulness, suggesting that waking results in the progressive accumulation of sleep need (Borbély and Achermann, 2000). In mammals, sleep intensity is reflected by slow-wave activity (SWA) in the nonrapid eye movement (NREM) sleep electroencephalogram, which increases in proportion to the time spent awake. However, the mechanisms responsible for the increase of NREM SWA after wakefulness remain unclear. According to a recent hypothesis (Tononi and Cirelli, 2003), the increase in SWA occurs because during wakefulness, many cortical circuits undergo synaptic potentiation, as evidenced by the widespread induction of long-term potentiation (LTP)-related genes in the brain of awake animals. A direct prediction of this hypothesis is that manipulations interfering with the induction of LTP-related genes should result in a blunted SWA response. Here, we examined SWA response in rats in which cortical norepinephrine (NA) was depleted, a manipulation that greatly reduces the induction of LTP-related genes during wakefulness (Cirelli and Tononi, 2004). We found that the homeostatic response of the lower-range SWA was markedly and specifically reduced after NA depletion. These data suggest that the wake-dependent accumulation of sleep need is causally related to cellular changes dependent on NA release, such as the induction of LTP-related genes, and support the hypothesis that sleep SWA homeostasis may be related to synaptic potentiation during wakefulness. [ABSTRACT FROM AUTHOR]

Background: The response of soft tissue sarcomas to cytotoxic chemotherapy is inconsistent. Biomarkers of chemoresistance or chemosensitivity are needed in order to identify appropriate patients for treatment. Given that many chemotherapeutics kill cells through direct DNA interactions, we hypothesized that upregulation of DNA damage response mechanisms would confer resistance to cytotoxic chemotherapy in sarcomas. To study this, we used spontaneously-occurring feline injection-site sarcomas (FISS). Methods: γH2AX and p53 expression were determined in biopsy samples of FISS. γH2AX expression was determined via immunohistochemistry whereas p53 expression was determined via qRT-PCR. Cell lines derived from these sarcoma biopsies were then treated with carboplatin (N = 11) or doxorubicin (N = 5) and allowed to grow as colonies. Colony forming-ability of cells exposed to chemotherapy was compared to matched, untreated cells and expressed as percent survival relative to controls. ImageJ was used for quantification. A mixed model analysis was performed to determine if an association existed between relative survival of the treated cells and γH2AX or p53 expression in the original tumors. Cell lines were validated via vimentin expression or growth as subcutaneous sarcomas in nude mice. Results: An association was detected between γH2AX expression and relative survival in cells exposed to carboplatin (P = 0.0250). In the 11 FISS tumors evaluated, γH2AX expression ranged from 2.2 to 18.8% (mean, 13.3%). Cells from tumors with γH2AX expression higher than the sample population mean had fourfold greater relative survival after carboplatin exposure than cells from tumors with γH2AX expression less than the mean. There was no association between relative survival after carboplatin exposure and p53 expression (P = 0.1608), and there was no association between relative survival after doxorubicin exposure and either γH2AX (P = 0.6124) or p53 (P = 0.8645) expression. Four cell lines were validated via growth as sarcomas in nude mice. Vimentin expression was confirmed in the other 7 cell lines. Conclusions: γH2AX expression, but not wild type p53, may potentially serve as a biomarker of resistance to platinum therapeutics in soft tissue sarcomas. To further investigate this finding, prospective, in vivo studies are indicated in animal models. [ABSTRACT FROM AUTHOR]

An effective tumoral delivery system should show minimal removal by the reticuloendothelial system (RES), promote tumor uptake and penetration, and minimize on‐site clearance. This study reports the design and synthesis of advanced self‐assembling peptide nanofiber precursor (NFP) analogues. The peptidic nature of NFP offers the design flexibility for on‐demand customization with imaging agents and surface charges while maintaining a set size, allowing for real‐time monitoring of kinetic and dynamic tumoral delivery by multimodal fluorescence/positron emission tomography/computed tomography (fluo/PET/CT) imaging, for formulation optimization. The optimized glutathione (GSH)‐NFP displays a reduced capture by the RES as well as excellent tumor targeting and tissue invasion properties compared to naïve NFP. Inside a tumor, GSH‐NFP can structurally transform into ten times larger interfibril networks, serving as in situ depot that promotes weeks‐long local retention. This nanofiber, which can further be designed to release the active pharmacophores within a tumor microenvironment, displays a superior therapeutic efficacy for inhibiting disease progression and improving the survival of animals bearing triple‐negative breast cancer tumors compared to free drug and liposome formulation of the drug, in addition to a favorable toxicity profile. A smart self‐assembling peptide nanofiber using a combined approach of shape‐controlled tumor uptake, charge‐assisted tissue penetration, and enzyme‐induced retention properties to improve the safety and the delivery of anticancer agents is presented. The nanofiber penetrates the tumor, invades and saturates it over time, and structurally transforms into larger interfibril network upon local enzyme activation, leading to weeks‐long retention capacity. [ABSTRACT FROM AUTHOR]