Brainstem auditory evoked responses in an equine patient population: part I--adult horses.

BackgroundBrainstem auditory evoked response has been an underused diagnostic modality in horses as evidenced by few reports on the subject.Hypothesis/objectivesTo describe BAER findings, common clinical signs, and causes of hearing loss in adult horses.AnimalsStudy group, 76 horses; control group, 8 horses.MethodsRetrospective. BAER records from the Clinical Neurophysiology Laboratory were reviewed from the years of 1982 to 2013. Peak latencies, amplitudes, and interpeak intervals were measured when visible. Horses were grouped under disease categories. Descriptive statistics and a posthoc Bonferroni test were performed.ResultsFifty-seven of 76 horses had BAER deficits. There was no breed or sex predisposition, with the exception of American Paint horses diagnosed with congenital sensorineural deafness. Eighty-six percent (n = 49/57) of the horses were younger than 16 years of age. The most common causes of BAER abnormalities were temporohyoid osteoarthropathy (THO, n = 20/20; abnormalities/total), congenital sensorineural deafness in Paint horses (17/17), multifocal brain disease (13/16), and otitis media/interna (4/4). Auditory loss was bilateral and unilateral in 74% (n = 42/57) and 26% (n = 15/57) of the horses, respectively. The most common causes of bilateral auditory loss were sensorineural deafness, THO, and multifocal brain disease whereas THO and otitis were the most common causes of unilateral deficits.Conclusions and clinical importanceAuditory deficits should be investigated in horses with altered behavior, THO, multifocal brain disease, otitis, and in horses with certain coat and eye color patterns. BAER testing is an objective and noninvasive diagnostic modality to assess auditory function in horses

Neurologic Deficits Including Auditory Loss and Recovery of Function in Horses with Temporohyoid Osteoarthropathy.

BackgroundAuditory loss is a common deficit in horses with temporohyoid osteoarthropathy (THO), however, recovery of function is unknown.Hypothesis/objectivesTo investigate neurologic function with emphasis in audition in horses with THO after treatment. To describe anatomical alterations of the petrous temporal bone that might result in auditory loss.AnimalsTwenty-four horses with a clinical diagnosis of THO.MethodsProspective study. A brainstem auditory evoked response (BAER) study was done as part of the criteria for inclusion in horses with a clinical diagnosis of THO from the years of 2005 to 2014. Physical and neurologic status and BAER findings were recorded. Brainstem auditory evoked response variables were compared by using Wilcoxon sign test. Fisher's exact test was also used. Significance was set at P < 0.05.ResultsThe most common signs included auditory loss (100% of horses), vestibular and facial nerve dysfunction (83%), and exposure ulcerative keratitis (71%). Concurrent left laryngeal hemiparesis was observed in 61% of horses through endoscopy. Auditory dysfunction was bilateral in 50% of the cases (complete and partial), and unilateral affecting more commonly the right ear (R = 8, L = 4). Short- and long-term follow-up revealed persistent auditory loss in all horses based on abnormal response to sound, and further confirmed through a BAER in 8 horses.Conclusions and clinical importanceAuditory dysfunction appears to be a permanent neurologic deficit in horses diagnosed with THO despite overall neurologic improvement

Brainstem auditory evoked responses in an equine patient population. Part II: foals.

BackgroundReports of the use of brainstem auditory evoked response (BAER) as a diagnostic modality in foals have been limited.Hypothesis/objectivesTo describe BAER findings and associated causes of hearing loss in foals.AnimalsStudy group 18 foals (15 neonatal, 3 nonneonatal), control group (5 neonatal foals).MethodsRetrospective. BAER records from the Clinical Neurophysiology Laboratory were reviewed from the years of 1982 to 2013. Peak latencies, amplitudes, and interpeak intervals were measured when visible. Clinical data were extracted from the medical records. Foals were grouped under disease categories. Descriptive statistics were performed.ResultsTen neonatal foals had complete absence of BAER bilaterally and 5 had findings within reference range. Abnormalities were associated with common neonatal disorders such as sepsis, neonatal encephalopathy, neonatal isoerythrolysis, and prematurity. BAER loss also was observed in foals with specific coat color patterns such as completely or mostly white with blue irides or lavender with pale yellow irides. An American Miniature foal with marked facial deformation also lacked BAER bilaterally. One nonneonatal foal with an intracranial abscess had no detectable BAER peaks bilaterally, and 2 older foals, 1 with presumed equine protozoal myeloencephalitis and the other with progressive scoliosis and ataxia, had BAER within normal limits.Conclusions and clinical importanceIn neonatal foals, BAER deficits commonly are complete and bilateral, and associated with common neonatal disorders and certain coat and eye color patterns. Sepsis, hypoxia, bilirubin toxicity, and prematurity should be investigated as potential causes of auditory loss in neonatal foals

Control of weak perturbations

Session 4aHT - Hot Topics: Aeroacoustics I: abstract 4aHT8Starting from p. 3207 of this journal issue is proceedings of ACOUSTICS 2012 HONG KONGWe define sound as being a weak perturbation in the properties of material consistent with the Navier-Stokes and continuity equations. Lighthill’s pioneering paper on aerodynamic noise gives an exact theory that enables interesting connections to be made between flow and sound. Aerodynamic noise being caused by quadrupoles is a good point of view, but what caused the quadrupoles? Were they possibly initiated by sound? Conclusions deduced from such a theory are not necessarily helpful, but they are true and might be very helpful indeed. The linear perturbations we call sound obey linear rules and it can be suppressed by anti-sound, a subject now becoming both practical and useful. The same must apply to any weak perturbation of a dynamic system perturbed from rest. Some perturbations are unstable and grow exponentially in their early weak state. They might be eliminated altogether by suppressing their linear form. The Rijke tube experiment shows that to be practical and shows also the close similarity that exists between acoustics and control theory. The lecture will give more examples of that type and suggest others that have yet to be demonstrated.published_or_final_versio

Significant familial differences in the frequency of abortion and Toxoplasma gondii infection within a flock of Charollais sheep

A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27 families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since 1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. Atotal of 155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000–2003. Significant differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging between 0% and 48% (P<0.01). Significantly different infection frequencies with T. gondii were also observed for different families and ranged between 0% and 100% (P<0.01). Although the actual cause of each abortion was not verified, a highly significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection in the same families (P<0.01). The data presented here raise further questions regarding the significance of congenital transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods in the future. Key words: Toxoplasma gondii, ovine, toxoplasmosis, congenital, transmission, pedigree, sheep

High levels of congenital transmission of toxoplasma gondii in longitudinal and cross-sectional studies on sheep farms provides evidence of vertical transmission in ovine hosts

Recent research suggests that vertical transmission may play an important role in sustaining Toxoplasma gondii infection in some species. We report here that congenital transmission occurs at consistently high levels in pedigree Charollais and outbred sheep flocks sampled over a 3-year period. Overall rates of transmission per pregnancy determined by PCR based diagnosis, were consistent over time in a commercial sheep flock (69%) and in sympatric (60%) and allopatric (41%) populations of Charollais sheep. The result of this was that 53·7% of lambs were acquiring an infection prior to birth: 46·4% of live lambs and 90·0% of dead lambs (in agreement with the association made between T. gondii and abortion). No significant differences were observed between lamb sexes. Although we cannot distinguish between congenital transmission occurring due to primary infection at pregnancy or reactivation of chronic infection during pregnancy, our observations of consistently high levels of congenital transmission over successive lambings favour the latter

Detection of high levels of congenital transmission of toxoplasma gondii in natural urban populations of mus domesticus

The relative importance of different transmission routes of Toxoplasma gondii has been a matter for debate. This ubiquitous parasite is generally thought to be transmitted by infective oocysts excreted by the definitive host, the cat. Ingestion of undercooked meat has also been considered an important route of transmission in many mammals while congenital transmission has generally been considered relatively rare. Experimental studies demonstrate the ability of T. gondii to be transmitted congenitally, but few studies have investigated the frequency of this transmission route in natural populations. We use PCR amplification of the SAG1 gene to investigate the frequency of congenital transmission in a wild population of mice (Mus domesticus) and show that congenital transmission is occurring in 75% of pregnancies in this population. Furthermore, for infected pregnant mice, transmission occurs to at least one foetus in 100% of cases while variable penetrance of congenital infection is observed. These high levels of congenital transmission in this wild population of mice, taken together with other recent data on congenital transmission in sheep, suggests that this phenomenon might be more widespread than previously thought

The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations

Neospora caninum and Toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. Little is known about the extent of Neospora/Toxoplasma co-infection in naturally infected populations of animals. Using nested PCR techniques, based on primers from the Nc5 region of N. caninum and SAG1 for T. gondii, the prevalence of N. caninum and its co-infection with T. gondii were investigated in populations of Mus domesticus, Rattus norvegicus and aborted lambs (Ovis aries). A low frequency of infection with N. caninum was detected in the Mus domesticus (3%) and Rattus norvegicus (4·4%) populations. A relatively high frequency of infection with N. caninum was detected in the brains of aborted lambs (18·9%). There was no significant relationship between N. caninum and T. gondii co-infection. Investigation of the tissue distribution of Neospora, in aborted lambs, showed that Neospora could not be detected in tissues other than brain and this was in contrast to Toxoplasma where the parasite could be frequently detected in a range of tissues

Fully Dynamic Matching in Bipartite Graphs

Maximum cardinality matching in bipartite graphs is an important and well-studied problem. The fully dynamic version, in which edges are inserted and deleted over time has also been the subject of much attention. Existing algorithms for dynamic matching (in general graphs) seem to fall into two groups: there are fast (mostly randomized) algorithms that do not achieve a better than 2-approximation, and there slow algorithms with \O(\sqrt{m}) update time that achieve a better-than-2 approximation. Thus the obvious question is whether we can design an algorithm -- deterministic or randomized -- that achieves a tradeoff between these two: a $o(\sqrt{m})$ approximation and a better-than-2 approximation simultaneously. We answer this question in the affirmative for bipartite graphs. Our main result is a fully dynamic algorithm that maintains a 3/2 + \eps approximation in worst-case update time O(m^{1/4}\eps^{/2.5}). We also give stronger results for graphs whose arboricity is at most \al, achieving a (1+ \eps) approximation in worst-case time O(\al (\al + \log n)) for constant \eps. When the arboricity is constant, this bound is $O(\log n)$ and when the arboricity is polylogarithmic the update time is also polylogarithmic. The most important technical developement is the use of an intermediate graph we call an edge degree constrained subgraph (EDCS). This graph places constraints on the sum of the degrees of the endpoints of each edge: upper bounds for matched edges and lower bounds for unmatched edges. The main technical content of our paper involves showing both how to maintain an EDCS dynamically and that and EDCS always contains a sufficiently large matching. We also make use of graph orientations to help bound the amount of work done during each update.Comment: Longer version of paper that appears in ICALP 201