Glioneuronal Hamartomas in the Central Nervous System of Two Goats.

Two goats (6 months old and 5 years old) were evaluated for neurological signs including laboured breathing, stiffness and obtundation. Solitary masses were noted in the brainstem and spinal cord, respectively. Histopathology of both cases revealed the lesions were composed of a mixture of glial and neuronal cells, consistent with glioneuronal hamartomas. The cause of death was attributed to the mass in the 6-month-old, while the cause of death in the 5-year-old was attributed to listeriosis. Hamartomas of neural origin are rarely described in veterinary species, and this report represents the first report of glioneuronal hamartomas in goats.

Littermate cats rescued from a shelter succumbed to acute, primary toxoplasmosis associated with TOXO DB genotype #4, generally circulating in wildlife.

Cats are important in the epidemiology of Toxoplasma gondii infection because they are the only hosts that can excrete the environmentally resistant oocysts in the environment. Although exposure is common (approximately 30% of cats in the USA), clinical toxoplasmosis is relatively rare. Here, we report overwhelming disseminated toxoplasmosis in two litter mate 8-week-old kittens, thought to have acquired toxoplasmosis postnatally. Five domestic shorthair kittens, approximately 2-3 weeks of age, and the queen were found in upstate New York by a rescue group in spring of 2018. The kittens and queen were placed in a foster home for approximately 4-5 weeks and then transferred to a shelter. Two kittens died unexpectedly following a short illness. Postmortem examination of the two deceased kittens revealed overwhelming toxoplasmosis and the presence of entero-epithelial stages in small intestine, suggestive of recent ingestion of infected tissues. Antibodies to T. gondii were found in the deceased kittens and the queen but not in the three asymptomatic littermate kittens. No obvious cause of immunosuppression was demonstrated. Genetic typing of T. gondii from DNA extracted from liver and lungs of both kittens revealed Toxo DB #4 genotype, commonly found in wildlife. Owners and veterinarians should be aware of dangers of feeding raw meat to cats and contact with infected cat feces. Procedures to safely handle T. gondii infected feces in hospital setting are outlined.

Parelaphostrongylus tenuis Cerebrospinal Nematodiasis in a Horse with Cervical Scoliosis and Meningomyelitis.

There are reports of horses with acute onset acquired cervical scoliosis and cutaneous analgesia. The underlying dorsal gray column myelitis that produces these neurologic signs has been only presumptively attributed to migration of Parelaphostrongylus tenuis within the spinal cord. Despite previous confirmation brain by polymerase chain reaction testing, of P. tenuis within the brain of horses by polymerase chain reaction testing, genetic testing has failed to definitively identify the presence of this parasite in cases of equine myelitis. This case report provides molecular confirmation via polymerase chain reaction of P. tenuis within the cervical spinal cord of a horse with scoliosis and cutaneous analgesia.

DNA damage is a feature of feline injection-site sarcoma.

Feline injection-site sarcoma (FISS) is commonly treated with surgery and radiation therapy. Despite aggressive therapy, FISS has a high recurrence rate. The true benefit of adjuvant chemotherapy is not known. DNA damage response mechanisms help protect against genomic instability but can also promote chemoresistance. In order to determine whether DNA damage is a feature of FISS, we evaluated tumour tissues with γH2AX immunohistochemistry. H2AX is phosphorylated to form γH2AX following DNA double strand breaks. Seventeen FISS specimens were evaluated prospectively. DNA damage ranged from 2.18 to33.7%, with a median of 16.2%. Significant differences were noted between cats (P < 0.0001). Mitotic index ranged from 0 to 57 with a median of 13 and did not correlate with γH2AX positivity (P = 0.2). Further studies are needed to determine if γH2AX expression may predict chemosensitivity and have independent value as a prognostic factor.

Holoprosencephaly and Pure Red Cell Aplasia in a Feline Leukaemia Virus-Positive Kitten.

A 9-month-old, female, domestic longhair cat with severe anaemia tested positive for feline leukaemia virus (FeLV) and was humanely destroyed and submitted for necropsy examination. Gross findings included a non-divided rostral telencephalon, consistent with semilobar holoprosencephaly. Histological examination of the bone marrow revealed an almost complete absence of erythroid precursor cells, consistent with pure red cell aplasia, and mild to moderate myelofibrosis. This case demonstrates a very unusual central nervous system defect, as well as an atypical presentation of pure red cell aplasia, in a FeLV-positive kitten.

HUS1 regulates in vivo responses to genotoxic chemotherapies.

Cells are under constant attack from genotoxins and rely on a multifaceted DNA damage response (DDR) network to maintain genomic integrity. Central to the DDR are the ATM and ATR kinases, which respond primarily to double-strand DNA breaks (DSBs) and replication stress, respectively. Optimal ATR signaling requires the RAD9A-RAD1-HUS1 (9-1-1) complex, a toroidal clamp that is loaded at damage sites and scaffolds signaling and repair factors. Whereas complete ATR pathway inactivation causes embryonic lethality, partial Hus1 impairment has been accomplished in adult mice using hypomorphic (Hus1(neo)) and null (Hus1(Δ1)) Hus1 alleles, and here we use this system to define the tissue- and cell type-specific actions of the HUS1-mediated DDR in vivo. Hus1(neo/Δ1) mice showed hypersensitivity to agents that cause replication stress, including the crosslinking agent mitomycin C (MMC) and the replication inhibitor hydroxyurea, but not the DSB inducer ionizing radiation. Analysis of tissue morphology, genomic instability, cell proliferation and apoptosis revealed that MMC treatment caused severe damage in highly replicating tissues of mice with partial Hus1 inactivation. The role of the 9-1-1 complex in responding to MMC was partially ATR-independent, as a HUS1 mutant that was proficient for ATR-induced checkpoint kinase 1 phosphorylation nevertheless conferred MMC hypersensitivity. To assess the interplay between the ATM and ATR pathways in responding to replication stress in vivo, we used Hus1/Atm double mutant mice. Whereas Hus1(neo/neo) and Atm(-/-) single mutant mice survived low-dose MMC similar to wild-type controls, Hus1(neo/neo)Atm(-/-) double mutants showed striking MMC hypersensitivity, consistent with a model in which MMC exposure in the context of Hus1 dysfunction results in DSBs to which the ATM pathway normally responds. This improved understanding of the inter-dependency between two major DDR mechanisms during the response to a conventional chemotherapeutic illustrates how inhibition of checkpoint factors such as HUS1 may be effective for the treatment of ATM-deficient and other cancers.

Phenotype-genotype correlations of facial width and height proportions in patients with Class II malocclusion.

OBJECTIVES: To characterize soft-tissue facial height and width variation in Class II malocclusion and test for correlations with genes HMGA2, AJUBA, and ADK. SETTING AND SAMPLE POPULATION: Nine facial proportions were estimated from 2D frontal repose photographs of 330 Caucasian adults with Class II malocclusion. MATERIAL AND METHODS: After adjustments for age and gender, the facial proportions were submitted to a principal component analyses (PCA). The most meaningful phenotypic variations were correlated with SNPs rs7924176 (ADK), rs17101923 (HMGA2), and rs997154 (AJUBA) genotyped in 106 individuals. RESULTS: Principal component analyses resulted in four principal components (PCs), which explained 75% of total variation. PC1 captured variation in the intercanthus distance and explained 28% of total variation. PC2 explained 21% of the variations in facial taper and facial index. PC3 explained 14% and reflected variations in the vertical dimension of the lower face. PC4 explained 12% and captured variations in distance between the eyes, width of the commissures, and the length of the superior aspect of the lower face height corresponding to the vertical dimension of the philtrum of the upper lip. A suggestive association (p<0.05) was observed between PC4 and rs997154 corroborating the role of AJUBA in variation of facial dimensions. CONCLUSION: 2D frontal photographs can be used to derive quantitative measures of soft-tissue phenotypes that are of clinical relevance. The methods described are suitable for discovery and replication of associations between genotypes and malocclusion phenotypes.

The ontogeny of the chin: an analysis of allometric and biomechanical scaling.

The presence of a prominent chin in modern humans has been viewed by some researchers as an architectural adaptation to buttress the anterior corpus from bending stresses during mastication. In contrast, ontogenetic studies of mandibular symphyseal form suggest that a prominent chin results from the complex spatial interaction between the symphysis and surrounding soft tissue and skeletal anatomy during development. While variation in chin prominence is clearly influenced by differential growth and spatial constraints, it is unclear to what degree these developmental dynamics influence the mechanical properties of the symphysis. That is, do ontogenetic changes in symphyseal shape result in increased symphyseal bending resistance? We examined ontogenetic changes in the mechanical properties and shape of the symphysis using subjects from a longitudinal cephalometric growth study with ages ranging from 3 to 20+ years. We first examined whether ontogenetic changes in symphyseal shape were correlated with symphyseal vertical bending and wishboning resistance using multivariate regression. Secondly, we examined ontogenetic scaling of bending resistance relative to bending moment arm lengths. An ontogenetic increase in chin prominence was associated with decreased vertical bending resistance, while wishboning resistance was uncorrelated with ontogenetic development of the chin. Relative to bending moment arm lengths, vertical bending resistance scaled with significant negative allometry whereas wishboning resistance scaled isometrically. These results suggest a complex interaction between symphyseal ontogeny and bending resistance, and indicate that ontogenetic increases in chin projection do not provide greater bending resistance to the mandibular symphysis.

Candidate Gene Analyses of Skeletal Variation in Malocclusion.

This study evaluated associations between craniofacial candidate genes and skeletal variation in patients with malocclusion. Lateral cephalometric radiographs of 269 untreated adults with skeletal classes I, II, and III malocclusion were digitized with 14 landmarks. Two-dimensional coordinates were analyzed using Procrustes fit and principal component (PC) analysis to generate continuous malocclusion phenotypes. Skeletal class classifications (I, II, or III) were used as a categorical phenotype. Individuals were genotyped for 198 single-nucleotide polymorphisms (SNPs) in 71 craniofacial genes and loci. Phenotype-genotype associations were tested via multivariate linear regression for continuous phenotypes and multinomial logistic regression for skeletal malocclusion class. PC analysis resulted in 4 principal components (PCs) explaining 69% of the total skeletal facial variation. PC1 explained 32.7% of the variation and depicted vertical discrepancies ranging from skeletal deep to open bites. PC1 was associated with a SNP near PAX5 (P = 0.01). PC2 explained 21.7% and captured horizontal maxillomandibular discrepancies. PC2 was associated with SNPs upstream of SNAI3 (P = 0.0002) and MYO1H (P = 0.006). PC3 explained 8.2% and captured variation in ramus height, body length, and anterior cranial base orientation. PC3 was associated with TWIST1 (P = 0.000076). Finally, PC4 explained 6.6% and detected variation in condylar inclination as well as symphysis projection. PC4 was associated with PAX7 (P = 0.007). Furthermore, skeletal class II risk increased relative to class I with the minor alleles of SNPs in FGFR2 (odds ratio [OR] = 2.1, P = 0.004) and declined with SNPs in EDN1 (OR = 0.5, P = 0.007). Conversely, skeletal class III risk increased versus class I with SNPs in FGFR2 (OR 2.2, P = 0.005) and COL1A1 (OR = 2.1, P = 0.008) and declined with SNPs in TBX5 (OR = 0.5, P = 0.014). PAX5, SNAI3, MYO1H, TWIST1, and PAX7 are associated with craniofacial skeletal variation among patients with malocclusion, while FGFR2, EDN1, TBX5, and COL1A1 are associated with type of skeletal malocclusion.

Stalled cerebral capillary blood flow in mouse models of essential thrombocythemia and polycythemia vera revealed by in vivo two-photon imaging.

BACKGROUND: Essential thrombocythemia (ET) and polycythemia vera (PV) are myeloproliferative neoplasms (MPNs) that share the JAK2(V617F) mutation in hematopoietic stem cells, leading to excessive production of predominantly platelets in ET, and predominantly red blood cells (RBCs) in PV. The major cause of morbidity and mortality in PV and ET is thrombosis, including cerebrovascular occlusive disease. OBJECTIVES: To identify the effect of excessive blood cells on cerebral microcirculation in ET and PV. METHODS: We used two-photon excited fluorescence microscopy to examine cerebral blood flow in transgenic mouse models that mimic MPNs. RESULTS AND CONCLUSIONS: We found that flow was 'stalled' in an elevated fraction of brain capillaries in ET (18%), PV (27%), mixed MPN (14%) and secondary (non-MPN) erythrocytosis (27%) mice, as compared with controls (3%). The fraction of capillaries with stalled flow increased when the hematocrit value exceeded 55% in PV mice, and the majority of stalled vessels contained only stationary RBCs. In contrast, the majority of stalls in ET mice were caused by platelet aggregates. Stalls had a median persistence time of 0.5 and 1 h in ET and PV mice, respectively. Our findings shed new light on potential mechanisms of neurological problems in patients with MPNs.

Role of DNA damage response pathways in preventing carcinogenesis caused by intrinsic replication stress.

Defective DNA replication can result in genomic instability, cancer and developmental defects. To understand the roles of DNA damage response (DDR) genes on carcinogenesis in mutants defective for core DNA replication components, we utilized the Mcm4(Chaos3/Chaos3) ('Chaos3') mouse model that, by virtue of an amino-acid alteration in MCM4 that destabilizes the MCM2-7 DNA replicative helicase, has fewer dormant replication origins and an increased number of stalled replication forks. This leads to genomic instability and cancer in most Chaos3 mice. We found that animals doubly mutant for Chaos3 and components of the ataxia telangiectasia-mutated (ATM) double-strand break response pathway (Atm, p21/Cdkn1a and Chk2/Chek2) had decreased tumor latency and/or increased tumor susceptibility. Tumor latency and susceptibility differed between genetic backgrounds and genders, with females demonstrating an overall greater cancer susceptibility to Atm and p21 deficiency than males. Atm deficiency was semilethal in the Chaos3 background and impaired embryonic fibroblast proliferation, suggesting that ATM drug inhibitors might be useful against tumors with DNA replication defects. Hypomorphism for the 9-1-1 component Hus1 did not affect tumor latency or susceptibility in Chaos3 animals, and tumors in these mice did not exhibit impaired ATR pathway signaling. These and other data indicate that under conditions of systemic replication stress, the ATM pathway is particularly important both for cancer suppression and viability during development.

Naturally occurring Parelaphostrongylus tenuis-associated choriomeningitis in a guinea pig with neurologic signs.

An adult male guinea pig (Cavia porcellus) with a 1-month history of hind limb paresis, torticollis, and seizures was euthanized and submitted for necropsy. Gross examination was unremarkable, but histologic examination revealed multifocal eosinophilic and lymphoplasmacytic choriomeningitis and cross sections of nematode parasites within the leptomeninges of the midbrain and diencephalon. Morphologic features of the nematode were consistent with a metastrongyle, and the parasite was identified as Parelaphostrongylus tenuis by polymerase chain reaction testing and nucleotide sequencing. Further questioning of the owner revealed that the guinea pig was fed grass from a yard often grazed by white-tailed deer (Odocoileus virginianus). To the authors' knowledge, this is the first report of a naturally occurring P. tenuis infection in a guinea pig.

Distal-less 3 haploinsufficiency results in elevated placental oxidative stress and altered fetal growth kinetics in the mouse.

Distal-less 3 (Dlx3)(-/-) mice die at E9.5 presumably due to an abnormal placental phenotype including reduced placental vasculature and secretion of placental growth factor. To examine the role of Dlx3 specifically within the epiblast, Dlx3 conditional knockout mice were generated using an epiblast-specific Meox2(CreSor) allele. Dlx3(-/fl), Meox2(CreSor) animals were born at expected frequencies and survived to weaning providing indirect evidence that loss of Dlx3 within the trophoectoderm plays a critical role in fetal survival in the Dlx3(-/-) mouse. We next examined the hypothesis that loss of a single Dlx3 allele would have a negative impact on placental and fetal fitness. Dlx3(+/-) mice displayed reduced fetal growth beginning at E12.5 compared with Dlx3(+/+) controls. Altered fetal growth trajectory occurred coincident with elevated oxidative stress and apoptosis within Dlx3(+/-) placentas. Oral supplementation with the superoxide dismutase mimetic, Tempol, rescued the fetal growth and placental cell death phenotypes in Dlx3(+/-) mice. To determine the potential mechanisms associated with elevated oxidative stress on the Dlx3(+/-) placentas, we next examined vascular characteristics within the feto-placental unit. Studies revealed reduced maternal spiral artery luminal area in the Dlx3(+/-) mice receiving water; Dlx3(+/-) mice receiving Tempol displayed maternal spiral artery luminal area similar to control Dlx3(+/+) mice. We conclude that reduced Dlx3 gene dose results in diminished fetal fitness associated with elevated placental cell oxidative stress and apoptosis coincident with altered vascular remodeling. Administration of antioxidant therapy ameliorated this feto-placental phenotype, suggesting that Dlx3 may be required for adaptation to oxidative stresses within the intrauterine environment.

Spontaneous unilateral brainstem infarction in Swiss mice.

Spontaneous vestibular syndrome in mice, characterized clinically by head tilt, circling or rolling, can be caused by otitis media, arteritis or central nervous system lesions. Postmortem examination of eleven non-inbred Swiss mice submitted for necropsy due to acute onset of vestibular signs revealed lesions consistent with brainstem infarction. The lesions were characterized by unilateral, well-demarcated areas of necrosis, malacia, and gliosis, with variable amounts of hemorrhage, in the lateral aspect of the medulla and caudal pons. The affected area included the medial, lateral and superior vestibular nuclei, the facial nucleus and the spinal trigeminal nucleus. While vestibular disease secondary to otitis media, periarteritis, and central nervous system neoplasia has been reported in many mouse strains, these unilateral brainstem infarctions were only seen in Swiss mice. These lesions share features with Wallenberg's Lateral Medullary Syndrome, the most common type of brainstem infarct in humans.

Deciduous canine and permanent lateral incisor differential root resorption.

When a permanent maxillary canine erupts apical to the permanent lateral incisor and the deciduous canine, resorption typically takes place only on the deciduous canine root. An understanding of this differential resorption could provide insight into the reasons for excessive iatrogenic root resorption during orthodontic tooth movement. The purpose of the present study was to examine the response of roots of permanent lateral incisors and deciduous canines to simulated resorption, and to acid and enzyme attack, reflecting the physiologic environment of an erupting permanent canine. Groups of maxillary permanent lateral incisor and deciduous canine roots were exposed to 5 combinations of Ten Cate demineralizing solution, Ten Cate demineralizing solution with EDTA, and a Type I collagenase solution. Sections of the roots were examined under a polarized light microscope. Analysis of variation of the resulting root lesions demonstrated that the lesion depths for deciduous canines were greater than those for permanent lateral incisors when averaged across 4 of the conditions (F(1,24) = 7.49, P =.0115). On average, deciduous canine roots demonstrated lesions 10% deeper than did permanent lateral incisor roots. We concluded that when deciduous canine and permanent lateral incisor roots are subjected to acid and enzyme attack, reflecting the physiologic environment of an erupting permanent canine, significantly deeper demineralized lesions are seen in the deciduous roots compared with the permanent roots. This finding may partially explain the differential root resorption during permanent tooth eruption.

Alveolar process fractal dimension and postcranial bone density.

OBJECTIVES: Our goal was to determine whether the radiographic fractal dimension of the maxillary and mandibular alveolar processes is related to bone density of the alveolar processes, spine, hip, and radius in healthy women. STUDY DESIGN: Thirty-seven dentate healthy white women aged 20 to 78 years underwent assessment of systemic and alveolar process bone. After a periodontal examination, D-speed vertical bite-wing and periapical radiographs with aluminum step wedges and a density correction algorithm were used to make alveolar process fractal dimension and density calculations within regions of interest that avoided crestal bone and intrabony defects. Anteroposterior (L1-L4) and lateral (L2-L4) lumbar spine, total hip, and total wrist densities were determined by means of dual energy x-ray absorptiometry. RESULTS: Correlation analysis revealed significant relationships between maxillary alveolar process fractal dimension and maxillary alveolar process density (r = 0.47, P < or =.01), mandibular alveolar process density (r = 0.48, P < or =.01), and mandibular alveolar process fractal dimension (r = 0.44, P < or =.05); and between mandibular alveolar process fractal dimension and maxillary alveolar process density (r = 0.54, P < or =.01) and mandibular alveolar process density (r = 0.58, P < or =.001). No significant relationships were found between the maxillary alveolar process or the mandibular alveolar process fractal dimension and the density of any postcranial regions. CONCLUSIONS: In healthy women, the alveolar process radiographic fractal dimension is significantly related to the alveolar process density but is not related to the density of the spine, hip, or radius.

The relationship between the density of the alveolar processes and that of post-cranial bone.

Skeletal mass declines in all populations with age, and the literature suggests that changes in oral bone may be linked to the status of the post-cranial (systemic) skeleton. However, there is a lack of information defining the relationship between alveolar process bone and the post-cranial skeleton in healthy individuals. The purpose of this study was to determine: (1) if the bone densities of the maxillary and mandibular alveolar processes are related to the bone density of the spine, hip, or radius in healthy women; and (2) if the alveolar process densities decline with age. Forty-one dentate Caucasian women aged 20 to 78 years underwent assessment of post-cranial (systemic) and alveolar process bone. D-speed vertical bitewing and periapical radiographs incorporating aluminum stepwedges, controlled exposure and processing conditions, and a density correction algorithm were used to make alveolar process density assessments with regions of interest (ROIs) apical to crestal bone and intrabony defects. Anteroposterior lumbar (L1 to L4) and lateral lumbar (L2 to L4) spine, total hip (and subregions), and radius bone densities were determined by dual-energy x-ray absorptiometry (DEXA). Correlation analysis revealed significant relationships between maxillary alveolar process bone density and the density of the mandibular alveolar process (r = 0.57, p < or = 0.001), anteroposterior lumbar spine (r = 0.53, p < or = 0.001), lateral lumbar spine (r = 0.52, p < or = 0.001), total hip (r = 0.39, p = 0.01), total radius (r = 0.39, p = 0.01), and age (r = -0.38, p = 0.01). A two-tailed t test comparison revealed significantly greater maxillary alveolar process bone density in women younger than 50 years of age than in those 50 and older (p < or = 0.01). We conclude that the density of maxillary alveolar process bone is significantly related to the density of the mandibular alveolar process, lumbar spine, hip, and radius in healthy women and that maxillary alveolar process bone density declines with age.

Evaluation of profile esthetic change with mandibular advancement surgery.

Our purpose was to investigate the impact of mandibular advancement surgery on profile esthetics and to attempt to define guidelines that could be of value to the clinician in predicting profile esthetic change. The sample consisted of 34 patients who had been treated with a combination of orthodontics and mandibular advancement surgery without genioplasty. Initial (pretreatment) and final (posttreatment) cephalometric radiographs of each patient were used to produce silhouette images and to quantify skeletal changes that occurred with surgery. The images were displayed randomly to lay persons and orthodontic residents who were asked to score the esthetics of each profile. On average, after mandibular advancement surgery, B point moved forward 5.0 mm (SD = 2.6 mm) and downward 4.7 mm (SD = 3.1 mm), and the ANB angle decreased 3.0 degrees (SD = 1.6 degrees ) Graphical analysis and results of paired t tests revealed that for patients with an initial ANB angle >/= 6 degrees, a consistent improvement in profile esthetics was seen following surgery (P

Mandibular bone density and fractal dimension in rabbits with induced osteoporosis.

OBJECTIVE: Our goal in this investigation was to examine the mandibular bone density and radiographic textural changes and the relationship between mandibular and spinal bone mineral density in an osteoporotic rabbit model. STUDY DESIGN: Three adult female New Zealand white rabbits in each of 4 groups received daily injections of cortisone acetate at a dosage of 0.0 (control), 3.0, 7.5, or 15.0 mg/kg for 4 weeks. The rabbits were then killed, and the mandible and spine of each animal were removed. Digital radiographs (70 kVp, 10 mA, 8 impulses) of the hemimandibles and spines were made. Lateral and anteroposterior bone densities of the lumbar spine (L2) were calculated, and average mandibular interdental bone density, fractal dimension, and gradient values were calculated. RESULTS: Correlation analysis revealed that cumulative steroid dose was strongly related to mandibular bone density (r = -0.80, P <.01), moderately related to mandibular fractal dimension (r = -0.61, P <. 05), and moderately related to anteroposterior lumbar spine density (r = -0.64, P <.05). Moderate correlations were found between mandibular interdental bone density and spinal density (r = 0.56, P <.05), but mandibular fractal dimension was not related to spinal density. CONCLUSIONS: In osteoporotic female rabbits, mandibular bone mineral density decreases in relation to spinal density and cumulative steroid dose. Mandibular fractal dimension decreases with cumulative steroid dose but is not significantly related to either mandibular density or spinal density.