Clinical signs, causes, and outcome of central cord syndrome in 22 cats.

OBJECTIVE: To describe the signalment, clinical findings, presumptive or definitive diagnosis, and outcome in cats with central cord syndrome (CCS). ANIMALS: 22 cats. CLINICAL PRESENTATION: Cats evaluated for CCS at 7 referral hospitals between 2017 and 2021 were included. Information retrieved from medical records included signalment, physical and neurological examination findings, diagnostic investigations, definitive or presumptive diagnosis, treatment, and follow-up. RESULTS: Median age at presentation was 9 years. Two neuroanatomical localizations were associated with CCS: C1-C5 spinal cord segments in 17 (77.3%) cats and C6-T2 spinal cord segments in 5 (22.7%) cats. Neuroanatomical localization did not correlate with lesion location on MRI in 8 (36.3%) cats. The most common lesion location within the vertebral column was over the C2 and C4 vertebral bodies in 6 (27.2%) and 5 (22.7%) cats, respectively. Peracute clinical signs were observed in 11 (50%) cats, acute in 1 (4.5%), subacute in 4 (18%), and chronic and progressive signs were seen in 6 (40.9%) cats. The most common peracute condition was ischemic myelopathy in 8 (36.3%) cats, whereas neoplasia was the most frequently identified chronic etiology occurring in 5 (22.7%) cats. Outcome was poor in 13 (59%) cats, consisting of 4 of 11 (36.6%) of the peracute cases, 3 of 4 (75%) of the subacute cases, and 6 of 6 of the chronic cases. CLINICAL RELEVANCE: Central cord syndrome can occur in cats with lesions in the C1-C5 and C6-T2 spinal cord segments. Multiple etiologies can cause CCS, most commonly, ischemic myelopathy and neoplasia. Prognosis depends on the etiology and onset of clinical signs.

Globoside and the mucosal pH mediate parvovirus B19 entry through the epithelial barrier.

Parvovirus B19 (B19V) is transmitted primarily via the respiratory route, however, the mechanism involved remains unknown. B19V targets a restricted receptor expressed in erythroid progenitor cells in the bone marrow. However, B19V shifts the receptor under acidic conditions and targets the widely expressed globoside. The pH-dependent interaction with globoside may allow virus entry through the naturally acidic nasal mucosa. To test this hypothesis, MDCK II cells and well-differentiated human airway epithelial cell (hAEC) cultures were grown on porous membranes and used as models to study the interaction of B19V with the epithelial barrier. Globoside expression was detected in polarized MDCK II cells and the ciliated cell population of well-differentiated hAEC cultures. Under the acidic conditions of the nasal mucosa, virus attachment and transcytosis occurred without productive infection. Neither virus attachment nor transcytosis was observed under neutral pH conditions or in globoside knockout cells, demonstrating the concerted role of globoside and acidic pH in the transcellular transport of B19V. Globoside-dependent virus uptake involved VP2 and occurred by a clathrin-independent pathway that is cholesterol and dynamin-dependent. This study provides mechanistic insight into the transmission of B19V through the respiratory route and reveals novel vulnerability factors of the epithelial barrier to viruses.

Computed Tomography-Guided Fine Needle Biopsies of Vertebral and Paravertebral Lesions in Small Animals.

Fine needle biopsy (FNB) is an effective, minimally invasive and inexpensive diagnostic technique. Under computed tomography (CT)-guidance, lesions that have a difficult approach can be sampled to reach a diagnosis. The aim of this study is to describe the use of CT-guidance to obtain FNB from vertebral and paravertebral lesions in small animals. Ten dogs and one ferret that had undergone CT-guided FNB of vertebral and paravertebral lesions and had a cytological or a histological diagnosis were included in this retrospective study. The FNB samples were taken in four cases from the vertebra, in two cases from the intervertebral disc and in five cases from the intervertebral foramen. Two infectious and nine neoplastic lesions were diagnosed. The percentage of successful FNB was 91%. The percentage of samples with a cytological diagnosis was 80%. The percentage of complications was 9%. Limitations were the small number of animals in the study, the lacking complementary percutaneous biopsies for comparison, the lacking final histological diagnoses in some cases and the intervention of multiple operators. Computed tomography-guided FNB is a useful and safe technique for the diagnosis of vertebral and paravertebral lesions in small animals. However, a degree of expertise is important.

A Conserved Receptor-Binding Domain in the VP1u of Primate Erythroparvoviruses Determines the Marked Tropism for Erythroid Cells.

Parvovirus B19 (B19V) is a human pathogen with a marked tropism for erythroid progenitor cells (EPCs). The N-terminal of the VP1 unique region (VP1u) contains a receptor-binding domain (RBD), which mediates virus uptake through interaction with an as-yet-unknown receptor (VP1uR). Considering the central role of VP1uR in the virus tropism, we sought to investigate its expression profile in multiple cell types. To this end, we established a PP7 bacteriophage-VP1u bioconjugate, sharing the size and VP1u composition of native B19V capsids. The suitability of the PP7-VP1u construct as a specific and sensitive VP1uR expression marker was validated in competition assays with B19V and recombinant VP1u. VP1uR expression was exclusively detected in erythroid cells and cells reprogrammed towards the erythroid lineage. Sequence alignment and in silico protein structure prediction of the N-terminal of VP1u (N-VP1u) from B19V and other primate erythroparvoviruses (simian, rhesus, and pig-tailed) revealed a similar structure characterized by a fold of three or four α-helices. Functional studies with simian parvovirus confirmed the presence of a conserved RBD in the N-VP1u, mediating virus internalization into human erythroid cells. In summary, this study confirms the exclusive association of VP1uR expression with cells of the erythroid lineage. The presence of an analogous RBD in the VP1u from non-human primate erythroparvoviruses emphasizes their parallel evolutionary trait and zoonotic potential.

Central cord syndrome: clinical features, etiological diagnosis, and outcome in 74 dogs.

OBJECTIVE: To describe the clinical and neurologic signs, diagnostic investigations, definitive or presumptive diagnosis, treatment, and outcome of dogs presented with acute onset central cord syndrome (CCS). ANIMALS: 74 client-owned dogs evaluated for CCS at 5 referral hospitals between January 2016 and March 2021. PROCEDURES: Data were collected from the medical records of each dog, including patient signalment, physical and neurologic examination results, presence of signs of respiratory failure, diagnostic imaging findings, definitive or presumptive diagnosis, treatment and follow-up information. Descriptive statistics were calculated and bivariable analysis was performed to identify associations between selected variables. RESULTS: 2 neuroanatomic locations for the CCS were identified: C1-C5 spinal cord segments in 65 of 74 (88%) dogs and C6-T2 in 9 (12%) dogs. Neurolocalization did not correlate with the imaging findings in 43 (58%) dogs. Different diseases were associated with CCS. The most common condition was Hansen type I disk herniation in 27 (36%) dogs and hydrated nucleus pulposus extrusion in 16 (22%) dogs. Main lesion locations within the vertebral column associated with CCS were C3-C4 and C4-C5 intervertebral disk spaces in 21 (28%) and 18 (24%) dogs, respectively. Outcome was favorable in 69 (93%) dogs. Patients presenting with hypoventilation were 14.7 times more likely to have a poor outcome. CLINICAL RELEVANCE: CCS in dogs may be seen with lesions in the C1-C5 and C6-T2 spinal cord segments. Etiologies are variable. Total or partial improvement was achieved in most dogs with the appropriate treatment. Hypoventilation was associated with death.

Herpes simplex virus co-infection facilitates rolling circle replication of the adeno-associated virus genome.

Adeno-associated virus (AAV) genome replication only occurs in the presence of a co-infecting helper virus such as adenovirus type 5 (AdV5) or herpes simplex virus type 1 (HSV-1). AdV5-supported replication of the AAV genome has been described to occur in a strand-displacement rolling hairpin replication (RHR) mechanism initiated at the AAV 3' inverted terminal repeat (ITR) end. It has been assumed that the same mechanism applies to HSV-1-supported AAV genome replication. Using Southern analysis and nanopore sequencing as a novel, high-throughput approach to study viral genome replication we demonstrate the formation of double-stranded head-to-tail concatemers of AAV genomes in the presence of HSV-1, thus providing evidence for an unequivocal rolling circle replication (RCR) mechanism. This stands in contrast to the textbook model of AAV genome replication when HSV-1 is the helper virus.

Human parvovirus B19 interacts with globoside under acidic conditions as an essential step in endocytic trafficking.

The glycosphingolipid (GSL) globoside (Gb4) is essential for parvovirus B19 (B19V) infection. Historically considered the cellular receptor of B19V, the role of Gb4 and its interaction with B19V are controversial. In this study, we applied artificial viral particles, genetically modified cells, and specific competitors to address the interplay between the virus and the GSL. Our findings demonstrate that Gb4 is not involved in the binding or internalization process of the virus into permissive erythroid cells, a function that corresponds to the VP1u cognate receptor. However, Gb4 is essential at a post-internalization step before the delivery of the single-stranded viral DNA into the nucleus. In susceptible erythroid Gb4 knockout cells, incoming viruses were arrested in the endosomal compartment, showing no cytoplasmic spreading of capsids as observed in Gb4-expressing cells. Hemagglutination and binding assays revealed that pH acts as a switch to modulate the affinity between the virus and the GSL. Capsids interact with Gb4 exclusively under acidic conditions and dissociate at neutral pH. Inducing a specific Gb4-mediated attachment to permissive erythroid cells by acidification of the extracellular environment led to a non-infectious uptake of the virus, indicating that low pH-mediated binding to the GSL initiates active membrane processes resulting in vesicle formation. In summary, this study provides mechanistic insight into the interaction of B19V with Gb4. The strict pH-dependent binding to the ubiquitously expressed GSL prevents the redirection of the virus to nonpermissive tissues while promoting the interaction in acidic intracellular compartments as an essential step in infectious endocytic trafficking.

Dural sac localization using myelography and its application to the lumbosacral epidural in dogs.

Background: The techniques described for the identification of the lumbosacral (LS) epidural space in dogs do not guarantee the needle position or an accidental subarachnoid puncture, especially in small size dogs. Aim: To determine the relationship between body weight and the location of the dural sac (DS) using myelography in dogs, and to determine the possibility of subarachnoid puncture during LS epidural based on the position of the DS. Methods: Four masked observers evaluated 70 myelographic studies of dogs, annotating the vertebrae where the DS ended, if it was localized before or after the LS space, and if accidental subarachnoid puncture during LS epidural injection was possible (yes/no). Body weight (kg) was categorized into: less than 10 kg, between 10 and 20 kg, and more than 20 kg and was also converted to body surface area (BSA) as a continuous variable. Results: The DS ended at the LS space or caudally in 50% of dogs. There was a statistically significant difference between the position of the DS and the dog's BSA (p = 0.001). The DS ended caudal to the LS space in 72.7% of dogs weighing <10 kg, in 25% of dogs between 10 and 20 kg and in 15% of dogs in the >20 kg category. The observers considered a possible subarachnoid puncture during LS epidural in 69.7% of patients <10 kg, 16.6% on those between 10 and 20 kg, and in 11.7% of the dogs >20 kg. Conclusion: The DS ended caudal to the LS space in almost 3/4 dogs in the <10 kg category, so accidental subarachnoid puncture during LS epidural is highly possible in this weight range.

Impact of the isoelectric point of model parvoviruses on viral retention in anion-exchange chromatography.

Anion-exchange chromatography (AEX) is used in the downstream purification of monoclonal antibodies to remove impurities and potential viral contamination based on electrostatic interactions. Although the isoelectric point (pI) of viruses is considered a key factor predicting the virus adsorption to the resin, the precise molecular mechanisms involved remain unclear. To address this question, we compared structurally homologous parvoviruses that only differ in their surface charge distribution. A single charged amino acid substitution on the capsid surface of minute virus of mice (MVM) provoked an increased apparent pI (pIapp ) 6.2 compared to wild-type MVM (pIapp = 4.5), as determined by chromatofocusing. Despite their radically different pIapp , both viruses displayed the same interaction profile in Mono Q AEX at different pH conditions. In contrast, the closely related canine parvovirus (pIapp = 5.3) displayed a significantly different interaction at pH 5. The detailed structural analysis of the intricate three-dimensional structure of the capsids suggests that the charge distribution is critical, and more relevant than the pI, in controlling the interaction of a virus with the chromatographic resin. This study contributes to a better understanding of the molecular mechanisms governing virus clearance by AEX, which is crucial to enable robust process design and maximize safety.

The VP1u of Human Parvovirus B19: A Multifunctional Capsid Protein with Biotechnological Applications.

The viral protein 1 unique region (VP1u) of human parvovirus B19 (B19V) is a multifunctional capsid protein with essential roles in virus tropism, uptake, and subcellular trafficking. These functions reside on hidden protein domains, which become accessible upon interaction with cell membrane receptors. A receptor-binding domain (RBD) in VP1u is responsible for the specific targeting and uptake of the virus exclusively into cells of the erythroid lineage in the bone marrow. A phospholipase A2 domain promotes the endosomal escape of the incoming virus. The VP1u is also the immunodominant region of the capsid as it is the target of neutralizing antibodies. For all these reasons, the VP1u has raised great interest in antiviral research and vaccinology. Besides the essential functions in B19V infection, the remarkable erythroid specificity of the VP1u makes it a unique erythroid cell surface biomarker. Moreover, the demonstrated capacity of the VP1u to deliver diverse cargo specifically to cells around the proerythroblast differentiation stage, including erythroleukemic cells, offers novel therapeutic opportunities for erythroid-specific drug delivery. In this review, we focus on the multifunctional role of the VP1u in B19V infection and explore its potential in diagnostics and erythroid-specific therapeutics.

Constrictive myelopathy secondary to caudal articular vertebral process dysplasia in West Highland white terrier dogs.

Clinical signs, imaging findings and long-term follow-up of 3 West Highland white terrier dogs with constrictive myelopathy secondary to caudal articular vertebral process dysplasia are described. Clinical signs were consistent with an acute or chronic T3-L3 myelopathy in all dogs. Diagnostic imaging revealed hypoplasia or aplasia of the caudal articular vertebral processes, extradural compressive myelographic pattern (hourglass-like pattern) with a reduced diameter of the spinal cord, and focal thickening of extradural soft tissues. Medical treatment initially improved the clinical signs in 2 dogs; however, mild proprioceptive deficits remained in all cases. Key clinical message: Constrictive myelopathy secondary to caudal articular vertebral process dysplasia in West Highland white terrier dogs should be considered as a differential diagnosis of an acute or chronic T3-L3 myelopathy in this breed.

Myélopathie constrictive secondaire à une dysplasie du processus articulaire caudal vertébral chez des chiens terriers West Highland white. Les signes cliniques, les trouvailles en imagerie et le suivi à longterme de trois chiens West Highland white avec myélopathie constrictive secondaire à une dysplasie du processus articulaire caudal vertébral sont décrits. Les signes cliniques étaient compatibles avec une myélopathie aiguë ou chronique au niveau T3­L3 chez tous les chiens. L'imagerie diagnostique a révélé une hypoplasie ou une aplasie des processus articulaires caudaux vertébraux, un patron myélographique de compression extra-dural (patron en sablier) avec un diamètre réduit de la moëlle épinière, et épaississement focal des tissus mous extra-duraux. Un traitement médical permis une amélioration des signes cliniques chez deux des chiens; toutefois, des déficits légers de proprioception ont persisté dans tous les cas.Message clinique clé:Une myélopathie constrictive secondaire à une dysplasie du processus articulaire caudal vertébral chez des chiens terriers West Highland white devrait être considérée comme un diagnostic différentiel d'une myélopathie aiguë ou chronique de T3­L3 chez cette race.(Traduit par Dr Serge Messier).

Comparison of the efficacy of 2 sedative protocols in pediatric dogs undergoing brainstem auditory-evoked response testing.

This study compared the quality of sedation with dexmedetomidine or alfaxalone during brainstem auditory-evoked response (BAER) tests in 6- to 17-week-old dogs. This was a prospective, randomized clinical study involving 19 client-owned pediatric dogs of breeds with reported congenital deafness. Group A (GA) received alfaxalone, 2 mg/kg body weight (BW) (n = 9) and group D (GD) dexmedetomidine, 0.005 mg/kg BW, and postprocedure antagonism with atipamezole (n = 10) intramuscularly. Time from injection to sedation, duration of sedation, sedation scores, need for re-dosing, rectal temperature, pulse and respiratory rate were recorded at baseline, before and after the BAER test, and once recovered from sedation. Pulse rate was significantly lower in GD (P = 0.004) and the number of re-dosing was significantly higher in GA (P = 0.011). Both sedation protocols allowed good quality BAER test recordings in pediatric dogs. Sedation with dexmedetomidine required less re-dosing, whereas alfaxalone maintained more physiological pulse rates.

Comparaison de l'efficacité de 2 protocoles de sédation chez des chiens pédiatriques soumis à un test potentiel évoqué auditif. L'étude vise à comparer deux protocoles de sédation à base de la dexmédétomidine et de l'alfaxalone pour la réalisation de test de potentiels évoqués auditifs (PEA) chez les chiens âgés de 6 à 17 semaines. Il s'agit d'une étude clinique prospective, randomisée, incluant 19 chiens pédiatriques de propriétaire, appartenant à des races prédisposées à la surdité congénitale. Les groupe A (GA) a reçu de l'alfaxalone (2 mg/kg) (n = 9), ceux du groupe D (GD) de la dexmédétomidine (0,005 mg/kg) (n = 10), en intramusculaire. Ont été relevés : temps d'action, durée de sédation, scores de sédation, nombre de doses, température, pouls et fréquence respiratoire; au repos, avant et après le test PEA. Des différences statistiquement significatives ont été trouvées dans la fréquence du pouls, étant plus bas pour GD (P = 0,004) alors que le nombre de doses utilisées, étant supérieurs parmi GA (P = 0,011). Trois chiens avaient une surdité unilatérale. Les deux protocoles de sédation ont permis des enregistrements de bonne qualité. La sédation avec la dexmédétomidine a nécessité moins de redosage; cependant, l'alfaxalone induit un pouls cardiaque plus proche des valeurs physiologiques chez les jeunes chiens testés.(Traduit par les auteurs).