As influenza viruses continue to jump species barriers to cause human infection, assessments of disease severity and viral replication kinetics in vivo provide crucial information for public health ...professionals. The ferret model is a valuable resource for evaluating influenza virus pathogenicity; thus, understanding the most effective techniques for sample collection and usage, as well as the full spectrum of attainable data after experimental inoculation in this species, is paramount. This is especially true for scheduled necropsy of virus-infected ferrets, a standard component in evaluation of influenza virus pathogenicity, as necropsy findings can provide important information regarding disease severity and pathogenicity that is not otherwise available from the live animal. In this review, we describe the range of influenza viruses assessed in ferrets, the measures of experimental disease severity in this model, and optimal sample collection during necropsy of virus-infected ferrets. Collectively, this information is critical for assessing systemic involvement after influenza virus infection in mammals.
Neonatal seizures can be refractory to conventional anticonvulsants, and this may in part be due to a developmental increase in expression of the neuronal Na(+)-K(+)-2 Cl(-) cotransporter, NKCC1, and ...consequent paradoxical excitatory actions of GABAA receptors in the perinatal period. The most common cause of neonatal seizures is hypoxic encephalopathy, and here we show in an established model of neonatal hypoxia-induced seizures that the NKCC1 inhibitor, bumetanide, in combination with phenobarbital is significantly more effective than phenobarbital alone. A sensitive mass spectrometry assay revealed that bumetanide concentrations in serum and brain were dose-dependent, and the expression of NKCC1 protein transiently increased in cortex and hippocampus after hypoxic seizures. Importantly, the low doses of phenobarbital and bumetanide used in the study did not increase constitutive apoptosis, alone or in combination. Perforated patch clamp recordings from ex vivo hippocampal slices removed following seizures revealed that phenobarbital and bumetanide largely reversed seizure-induced changes in EGABA. Taken together, these data provide preclinical support for clinical trials of bumetanide in human neonates at risk for hypoxic encephalopathy and seizures.
Sudden-onset sensorineuronal hearing loss (SNHL) is reported in approximately one-third of survivors of Lassa fever (LF) and remains the most prominent cause of Lassa virus (LASV)-associated ...morbidity in convalescence. Using a guinea pig model of LF, and incorporating animals from LASV vaccine trials, we investigated viral antigen distribution and histopathology in the ear of infected animals to elucidate the pathogenesis of hearing loss associated with LASV infection. Antigen was detected only in animals that succumbed to disease and was found within structures of the inner ear that are intimately associated with neural detection and/or translation of auditory stimuli and in adjacent vasculature. No inflammation or viral cytopathic changes were observed in the inner ear or surrounding structures in these animals. In contrast, no viral antigen was detected in the ear of surviving animals. However, all survivors that exhibited clinical signs of disease during the course of infection developed perivascular mononuclear inflammation within and adjacent to the ear, indicating an ongoing inflammatory response in these animals that may contribute to hearing loss. These data contribute to the knowledge of LASV pathogenesis in the auditory system, support an immune-mediated process resulting in LASV-associated hearing loss, and demonstrate that vaccination protecting animals from clinical disease can also prevent infection-associated auditory pathology.
•LASV antigen detection in the inner ear was limited to guinea pigs that succumbed to disease.•LASV antigen was found within structures that are associated with neural detection and/or translation of auditory stimuli.•No viral antigen was detected in the ear of any guinea pig that survived infection.•Perivascular mononuclear inflammation was observed in all survivors that exhibited clinical signs of LF.
Lassa virus (LASV), a hemorrhagic fever virus endemic to West Africa, causes conjunctivitis in patients with acute disease. To examine ocular manifestations of LASV, we histologically examined eyes ...from infected guinea pigs. In fatal disease, LASV immunostaining was most prominent in the anterior uvea, especially in the filtration angle, ciliary body, and iris and in and around vessels in the bulbar conjunctiva and peripheral cornea, where it co-localized with an endothelial marker (platelet endothelial cell adhesion molecule). Antigen was primarily associated with infiltration of T-lymphocytes around vessels in the anterior uvea and with new vessel formation at the peripheral cornea. In animals that exhibited clinical signs but survived infection, eyes had little to no inflammation and no LASV immunostaining 6 weeks after infection. Overall, in this model, LASV antigen was restricted to the anterior uvea and was associated with mild chronic inflammation in animals with severe disease but was not detected in survivors.
Dorsally located corneal dermoid in a cat LoPinto, Alexander J; Pirie, Chris G; Huynh, Thanhthao ...
JFMS open reports,
01/2016, Letnik:
2, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A 2-month-old, male kitten was presented for evaluation of unilateral blepharospasm and epiphora involving the right eye. Ocular examination revealed conjunctivitis, a superficial corneal ulcer, ...reflex anterior uveitis and a haired mass within the dorsal cornea of the right eye. The mass was subsequently removed surgically via a lamellar keratectomy. Histologic evaluation of the mass via light microscopy revealed it to be comprised of normal-haired skin with mild inflammation. One week after surgical removal and medical management of the corneal ulcer, all ocular clinical signs had resolved with minimal corneal scarring. On re-examination 6 months following surgical excision of the mass, the kitten was noted to be comfortable with no significant corneal scarring. To our knowledge, this is the first case report of a dorsally located corneal dermoid in a cat.
Understanding the mechanisms of neuronal regeneration and repair in the adult central nervous system is a vital area of research. Using a rhesus lentiviral encephalitis model, we sought to determine ...whether recovery of neuronal metabolism after injury coincides with the induction of two important markers of synaptodendritic repair: growth-associated protein-43 (GAP-43) and ephrin B3. We examined whether the improvement of neuronal metabolism with combined anti-retroviral therapy (cART) after simian immunodeficiency virus (SIV) infection in rhesus macaques involved induction of GAP-43, also known as neuromodulin, and ephrin B3, both implicated in axonal pathfinding during neurodevelopment and regulation of synapse formation, neuronal plasticity, and repair in adult brain. We utilized magnetic resonance spectroscopy to demonstrate improved neuronal metabolism in vivo in adult SIV-infected cART animals compared to untreated and uninfected controls. We then assessed levels of GAP-43, ephrin B3, and synaptophysin, a pre-synaptic marker, in three brain regions important for cognitive function, cortex, hippocampus, and putamen, by quantitative real-time RT-PCR and immunohistochemistry. Here we demonstrate that (1) GAP-43 mRNA and protein are induced with SIV infection, (2) GAP-43 protein is higher in the hippocampus outer molecular layer in SIV-infected animals that received cART compared to those that did not, and (3) activated microglia and infiltrating SIV-infected macrophages express abundant ephrin B3, an important axonal guidance molecule. We propose a model whereby SIV infection triggers events that lead to induction of GAP-43 and ephrin B3, and that short-term cART results in increased magnitude of repair mechanisms especially in the hippocampus, a region known for high levels of adult plasticity.
Tuberous sclerosis complex is a disease caused by mutations in the TSC1 or TSC2 genes, which encode a protein complex that inhibits mTOR kinase signaling by inactivating the Rheb GTPase. Activation ...of mTOR promotes the formation of benign tumors in various organs and the mechanisms underlying the neurological symptoms of the disease remain largely unknown. We found that Tsc2 haploinsufficiency in mice caused aberrant retinogeniculate projections that suggest defects in EphA receptor-dependent axon guidance. We also found that EphA receptor activation by ephrin-A ligands in neurons led to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) activity and decreased inhibition of Tsc2 by ERK1/2. Thus, ephrin stimulation inactivates the mTOR pathway by enhancing Tsc2 activity. Furthermore, Tsc2 deficiency and hyperactive Rheb constitutively activated mTOR and inhibited ephrin-induced growth cone collapse. Our results indicate that TSC2-Rheb-mTOR signaling cooperates with the ephrin-Eph receptor system to control axon guidance in the visual system.
This manuscript describes the Child Health and Mortality Prevention Surveillance (CHAMPS) network approach to pathologic evaluation of minimally invasive tissue sampling (MITS) specimens, including ...guidelines for histopathologic examination and further diagnostics with special stains, immunohistochemistry, and molecular testing, as performed at the CHAMPS Central Pathology Laboratory (CPL) at the Centers for Disease Control and Prevention, as well as techniques for virtual discussion of these cases (telepathology) with CHAMPS surveillance locations. Based on review of MITS from the early phase of CHAMPS, the CPL has developed standardized histopathology-based algorithms for achieving diagnoses from MITS and telepathology procedures in conjunction with the CHAMPS sites, with the use of whole slide scanners and digital image archives, for maximizing concurrence and knowledge sharing between site and CPL pathologists. These algorithms and procedures, along with lessons learned from initial implementation of these approaches, guide pathologists at the CPL and CHAMPS sites through standardized diagnostics of MITS cases, and allow for productive, real-time case discussions and consultations.
We report herein a fatal case of acute human orthopneumovirus (formerly respiratory syncytial virus) infection in a captive white-handed gibbon (Hylobates lar). Other members of the housing group had ...mild respiratory signs. Gross examination revealed bilateral pulmonary congestion and froth in the bronchi. Microscopically, the lungs had lymphocytic, neutrophilic infiltration of the interstitium and alveolar walls. There was necrosis of terminal bronchiolar epithelium and terminal bronchioles, and surrounding alveoli contained necrotic and exfoliated epithelial cells admixed with histiocytes and syncytial cells. Additional lesions included nonsuppurative meningoencephalitis, and epidermal hyperkeratosis and hyperplasia with syncytial cell formation. PCR screening for 12 human respiratory viruses was positive for orthopneumovirus in multiple tissues, including lung, and immunohistochemical staining for human orthopneumovirus detected viral antigen within bronchial epithelial cells. IHC and PCR for measles virus on preserved sections were negative. White-handed gibbons have not been previously reported as hosts for human orthopneumovirus, an important respiratory pathogen of both primates and humans.
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