Avian riboflavin deficiency causes reliably reproducible peripheral nerve demyelination and, with vitamin supplementation, rapid remyelination.

Riboflavin deficiency produces severe peripheral neve demyelination in young, rapidly growing chickens. While this naturally-occurring vitamin B2 deficiency can cause a debilitating peripheral neuropathy, and mortality, in poultry flocks, it can also be a useful experimental animal model to study the pathogenesis of reliably reproducible peripheral nerve demyelination. Moreover, restitution of normal riboflavin levels in deficient birds results in brisk remyelination. It is the only acquired, primary, demyelinating tomaculous neuropathy described to date in animals. The only other substance that causes peripheral nerve demyelination similar to avian riboflavin deficiency is tellurium and the pathologic features of the peripheral neuropathy produced by this developmental neurotoxin in weanling rats are also described.

An Unusual Cause of Femoral Nerve Paresis in a Horse: Disseminated B Cell Lymphoma With Plasmacytoid Differentiation and Direct Neuronal Invasion.

A 21-year-old Quarter Horse mare presented with a chronic, progressively worsening left pelvic limb lameness of 3 weeks duration. The initial examination identified a consistent lameness at a walk. Neurological examination showed sensory and gait abnormalities consistent with left femoral nerve dysfunction. The horse minimally advanced the leg cranially and had a shortened stride length at the walk. During the stance phase, the heels of the left hind foot did not contact the ground and the horse quickly took weight off of the limb. Diagnostic imaging (ultrasound and nuclear scintigraphy) examinations did not reveal a cause. Severe lymphocytosis was identified on complete blood cell count (69,600 cells /uL; reference range: 1,500-4,000 cells/uL), suggestive of lymphoma. Postmortem examination revealed focal swelling of the left femoral nerve. Multiple masses were found in the stomach, large colon, adrenal gland, mesentery, heart, and meninges. The entire left pelvic limb was dissected and did not reveal other causes of the gait deficit. Histologic evaluation of the left femoral nerve revealed disseminated intermediate cell size B cell lymphoma, with an immunophenotype suggestive of plasmacytoid differentiation. These lymphocytes infiltrated the femoral nerve at the location of the focal nerve swelling, in addition to other peripheral nerves. This case highlights a horse with an atypical diagnosis of femoral nerve paresis caused by direct neoplastic lymphocyte infiltration, deriving from disseminated B cell lymphoma with plasmacytoid differentiation (neurolymphomatosis). Though rare, disseminated lymphoma with direct nerve infiltration should be considered in horses with peripheral neuropathies.

Peripheral neuropathy caused by fenugreek (Trigonella foenum-graecum) straw intoxication in cattle and experimental reproduction in sheep and goats.

Trigonella foenum-graecum (fenugreek) is a legume widely used as a food supplement in humans and less frequently in ruminants. Toxicity has been described sporadically in ruminants grazing mature fenugreek plants or stubble; however, the pathological features are unclear. This report describes a natural outbreak of intoxication in cattle fed fenugreek straw and the experimental reproduction using 8 sheep and 8 goats. Affected cattle presented clinical signs approximately 1 month after consuming the straw and 100 of 400 cattle (25%) were affected, of which 60 of 100 (60%) died or were euthanized. Clinical signs were characterized by proprioceptive positioning defects with abnormal postures and weakness of hindlimbs. Forelimbs were also affected in severely affected animals, and cattle became recumbent. Locomotion was characterized by trembling, and some cattle showed high-stepping movements of their forelimbs and knuckled over in their fetlocks. Experimental intoxication induced clinical signs only in sheep and were similar to cattle, although with signs starting in the forelegs. Gross and microscopic lesions were similar in spontaneous and experimental intoxications. Macroscopic changes corresponded with muscular hemorrhages and edema, mainly surrounding the peripheral nerves. Microscopic examination only demonstrated lesions in the distal peripheral nerves, which included edema, hemorrhages, and Wallerian degeneration. Neurofilament immunohistochemistry revealed altered axon labeling and S100 showed a decrease in myelin intensity and loss of its typical compact arrangement around axons. Biochemical and hematological abnormalities included elevated levels of muscle and liver enzymes and thrombocytopenia. These findings indicate that fenugreek straw induces peripheral neuropathy in cattle and sheep, but not in goats.

[Treatment, clinical course and outcome of tibial neuropathy in German Holstein cows]. / Behandlung, Verlauf und Therapieerfolg der Neuropathie des Nervus tibialis bei Deutsch-Holstein Kühen.

OBJECTIVE: As a follow-up to a previous study on the incidence, history and clinical findings of tibial neuropathy (TN), the present work aimed at describing the treatment and prognosis of this disease. MATERIALS AND METHODS: Of 88 German Holstein dairy cows with unilateral (UTN, n = 71) or bilateral (BTN, n = 17) TN, 68 (56 UTN, 12 BTN) with a complete data set were analyzed. They were retrospectively assigned to one of four groups: no treatment - spontaneous healing within 48 h (Spontaneous, 5 UTN), no bandage (0Cast, 8 UTN, 3 BTN) or treatment with anti-inflammatory drugs and support bandage (StV, 3 UTN) or fiberglass cast (Cast, 40 UTN, 9 BTN). Treated cows were re-examined five times (14, 21, 28, 42 and 56 days after the first presentation). The plasma activity of creatine kinase was measured at the last re-examination in 29 cows similar to measurement at day 0. RESULTS: The observed overall success rate of treatment of cows with UTN was considerably higher compared with untreated cows (Cast 98 % and StV 100 % vs. 0Cast 62 %). By comparison, the observed difference between treated and untreated cows with BTN was not so clear (78 % vs. 67 %). Recovering cows exhibited a calculated longer median survival time than cows that did not recover (545 d vs. 100 d). Plasma creatine kinase activities were increased initially and returned within the reference interval (434 U/l and 152 U/L) following treatment. CONCLUSIONS: Cows with ETN have an excellent prognosis provided that treatment with anti-inflammatory drugs and stabilizing bandage is administered. In cows with BTN, the prognosis depended on the type and degree of the primary injury. Loss of skin sensitivity indicated a poor prognosis. From an economic standpoint, treatment of TN is indicated provided that the prognosis is good. In cows that had healed clinically, the average survival time extended into the following lactation. CLINICAL RELEVANCE: This study highlights the advantages of a support bandage for the treatment of cows with TN. Compared with other peripheral neuropathies, muscle damage appears to be of particular importance in TN.

Immunohistochemical analysis of laryngeal muscle of horses clinically affected with recurrent laryngeal neuropathy.

BACKGROUND: As myosin heavy chain (MyHC) profile of muscle fibres is heavily influenced by neural input, changes in MyHC expression are expected in horses clinically affected with recurrent laryngeal neuropathy (RLN) yet, this has not been thoroughly investigated. OBJECTIVES: To describe the changes in MyHC and fibre diameter in left cricoarytenoideus dorsalis (L-CAD) muscle of horses with clinical signs of RLN. STUDY DESIGN: Observational cohort study. METHODS: Immunohistochemistry was used to assess the MyHC-based fibre-type proportion, size and grouping in the L-CAD of 10 Thoroughbred horses, five clinically affected with RLN and five unaffected controls based on resting endoscopic examination. The Mann-Whitney U test was used to compare the two groups. RESULTS: Compared to controls (of mean age 3.0 ± 1.7 years) which only expressed type I, IIA and IIX MyHC, the L-CAD of affected horses (of mean age 2.8 ± 0.8 years) had obvious fibre-type grouping, and despite apparent compensatory hypertrophy of a small number of fibres, a decrease in overall fibre diameter (median difference -35.2 µm, 95% CI -47.4 to -7.9, P = .02) and diameter of type IIA fibres (median difference -46.8 µm, 95% CI -52.1 to -5.0, P = .03) was observed. Anti-fast MyHC (MY32) cross-immunoreacted with embryonic-MyHC. Whereas MY32-positive fibres were identified as type IIX in controls, in affected horses these fibres were less than 50 µm diameter with internal nuclei and were MYH3-positive for embryonic myosin indicating depletion of type IIX fibres, yet active regeneration and fibre renewal. MAIN LIMITATIONS: Small sample size that did not include subclinical cases. Fibre size and appearance rather than staining colour were relied upon to differentiate embryonic from type IIX MyHC. CONCLUSIONS: Horses clinically affected with RLN have overall atrophy of fibres, loss of IIX fibres and expression of embryonic myosin indicating regenerative capacity. Despite hypertrophy of some remaining fibres, the overall decline in the bulk of fibres, including those most fatigue-resistant, may be the critical change that results in failure to maintain arytenoid abduction during exercise although direct comparison to subclinical cases is needed to confirm this.

Comparative Pathology of the Peripheral Nervous System.

The peripheral nervous system (PNS) relays messages between the central nervous system (brain and spinal cord) and the body. Despite this critical role and widespread distribution, the PNS is often overlooked when investigating disease in diagnostic and experimental pathology. This review highlights key features of neuroanatomy and physiology of the somatic and autonomic PNS, and appropriate PNS sampling and processing techniques. The review considers major classes of PNS lesions including neuronopathy, axonopathy, and myelinopathy, and major categories of PNS disease including toxic, metabolic, and paraneoplastic neuropathies; infectious and inflammatory diseases; and neoplasms. This review describes a broad range of common PNS lesions and their diagnostic criteria and provides many useful references for pathologists who perform PNS evaluations as a regular or occasional task in their comparative pathology practice.

HINDLIMB PARALYSIS SYNDROME IN WILD CARNABY'S COCKATOOS (CALYPTORHYNCHUS LATIROSTRIS): A NEW THREAT FOR AN ENDANGERED SPECIES.

Carnaby's Cockatoos (Calyptorhynchus latirostris) are in decline in SW Western Australia from several processes, including habitat loss and fragmentation. However, in recent years, a disease syndrome has also emerged as a significant population threat. Emerging diseases in wildlife have the potential for catastrophic effects on population numbers, especially if a species is experiencing existing pressure from other threatening processes. This article describes an investigation into a hindlimb paralysis syndrome that has occurred in the summer and autumn since 2012 in 84 wild Carnaby's Cockatoos. Recovery from the syndrome has been demonstrated in 21 of 33 cases when supportive therapy was applied. Although a definitive diagnosis has not been obtained, the hypothesized etiology is an organophosphate-induced delayed-onset neuropathy. The syndrome may indicate that interaction between the cockatoos and inland agricultural practices are affecting this migratory species in ways that are, so far, poorly understood.

External transcutaneous ultrasound technique in the equine cricoarytenoideus dorsalis muscle: Assessment of muscle size and echogenicity with resting endoscopy.

BACKGROUND: Recent studies have assessed the cricoarytenoideus dorsalis muscle (CAD) using transoesophageal ultrasonography in equine recurrent laryngeal neuropathy (RLN). We assessed the CAD using the external transcutaneous ultrasound technique, which may constitute an easier method in horses. OBJECTIVES: To evaluate ultrasonographic imaging of the left cricoarytenoideus dorsalis muscle (LCAD) and right cricoarytenoideus dorsalis muscle (RCAD) as a diagnostic tool for RLN using the transcutaneous ultrasound technique. STUDY DESIGN: Cross-sectional study. METHODS: The axial plane thickness, cross-sectional area and echogenicity of the LCAD and RCAD were measured using transcutaneous ultrasonography in 164 horses. Assessments of LCAD were compared with those of RCAD. The LCAD:RCAD ratios in thickness and area were compared between control horses (resting grades 1 and 2) and horses with resting laryngeal grades 3 and 4 using the Havemeyer 4-point grading system with subgrades. RESULTS: The LCAD:RCAD ratios for thickness and area were 0.69 and 0.66 in horses with resting grades 3 and 4 respectively; LCAD was more hyperechogenic than RCAD in resting grades 3 and 4. LCAD:RCAD ratios for thickness and area in grades 3.II, 3.III and 4 were significantly lower than those in control horses. Thickness and area of the LCAD were negatively correlated with resting laryngeal grade MAIN LIMITATIONS: Overground endoscopy was not performed in this study. There were some differences in methodology: measurement of the physical thickness of the LCAD and clipping of hair at the laryngeal region were only performed in horses that underwent laryngoplasty. CONCLUSIONS: Results of ultrasonographic assessments of the CAD using transcutaneous ultrasonography were similar to those obtained by transoesophageal ultrasonography. This technique enables a simple, noninvasive, direct and easy examination. Assessment of the CAD using transcutaneous ultrasonography may be a useful technique and a potential option for determining whether to perform nerve graft or laryngoplasty.

Suprascapular nerve decompression for treatment of neuropathy in a bucking bull.

CASE DESCRIPTION: A 3-year-old 639-kg (1,406-lb) American bucking bull was examined because of a 4-day history of right forelimb lameness that began after the bull sustained an injury to the right shoulder region while exiting the chute during a rodeo. CLINICAL FINDINGS: A 10 × 10-cm soft tissue swelling was present over the right shoulder region. Ultrasonographically, the contour of the scapular spine, bicipital bursa, bicipital tendon, and greater tubercle of the humerus appeared unremarkable; the swelling appeared to be a hematoma overlying the distal aspect of the scapula. No external wounds, palpable joint effusion, or swellings were noted on examination of the distal portions of the limbs. The bull developed atrophy of the supraspinatus and infraspinatus muscles with lateral abduction of the shoulder joint when walking. Electromyography revealed decreased innervation to the supraspinatus and infraspinatus muscles consistent with suprascapular neuropathy. TREATMENT AND OUTCOME: The suprascapular nerve was surgically decompressed by removing the entrapping hematoma and periosteum and performing a notch resection of the scapula; dexamethasone (40 mg) was administered prior to closure. The bull was discharged 5 days after surgery; no lameness was evident at the time of discharge. The owner was instructed to restrict the bull to a stall or small pen for 6 weeks. Four months after surgery, the muscle atrophy had substantially improved, and the bull returned to bucking. CLINICAL RELEVANCE: Findings suggested that suprascapular neuropathy can develop in bulls secondary to injury and that suprascapular nerve decompression may improve nerve function, muscle atrophy, and gait.

Histopathological lesions in reproductive organs, distal spinal cord and peripheral nerves of horses naturally infected with Trypanosoma equiperdum.

BACKGROUND: Dourine, a venereal transmitted trypanosomosis caused by Trypanosoma equiperdum, has different clinical signs related to the reproductive and nervous system. Pathologic tissue changes associated with the disease are poorly described. The present study describes the histopathological lesions in naturally T. equiperdum-infected horses in the chronical stage of dourine. RESULTS: Four chronically dourine diseased horses underwent a post-mortem examination. They were Woo test negative, but CATT/T. evansi positive, had a low packed cell volume (PCV) and exhibited obvious clinical signs of dourine. Post-mortem examination did not reveal gross lesions in the organs assumed to be responsible for the symptomatology. On histopathology, genital organs were affected, with mononuclear cell infiltration and erosions and degeneration of seminiferous tubules and perivascular lymphoplasmacytic cuffing in the uterus. In the nervous system, mononuclear cell infiltration was located in peripheral nerves, ganglia and in the spinal cord, leading to axonal degeneration. Real-time PCR using ITS primer revealed the presence of trypanosomes in these organs and conventional PCRs using maxicircle and RoTat1.2 primers further confirmed the involvement of T. equiperdum since the DNAs from the vagina, testicle, distal spinal cord, sciatic and obturator nerves found to be positive for maxicircle and negative for RoTat 1.2. CONCLUSIONS: The histopathological lesions in the spinal cord and peripheral nerves explain the incoordination of the hind legs in T. equiperdum-infected horses, whilst its presence in the genital tract exemplifies the venereal transmission.

Use of real-time PCR to rule out Marek's disease in the diagnosis of peripheral neuropathy.

This article reports nine cases of neurological disease in brown layer pullets that occured in various European countries between 2015 and 2018. In all cases, the onset of neurological clinical signs was at 4-8 weeks of age and they lasted up to 22 weeks of age. Enlargement of peripheral nerves was the main lesion observed in all cases. Histopathological evaluation of nerves revealed oedema with moderate to severe infiltration of plasma cells. Marek's disease (MD) was ruled out by real-time PCR as none of the evaluated tissues had a high load of oncogenic MD virus (MDV) DNA, characteristics of MD. Based on the epidemiological data (layers with clinical signs starting at 5-8 weeks of age), gross lesions (peripheral nerve enlargement with a lack of tumours in other organs), histopathological lesions (oedema and infiltration of plasma cells), and no evidence of high load of MDV DNA, we concluded that those cases were due to peripheral neuropathy (PN). PN is an autoimmune disease easily misdiagnosed as MD, leading to a costly enforcement of the vaccination protocol. Additional vaccination against MD does not protect against PN and could worsen the clinical signs by over-stimulating the immune system. Differential diagnosis between PN and MD should always be considered in cases of neurological disease with enlargement of peripheral nerves as the only gross lesion. This case report shows for the first time how real-time PCR to detect oncogenic MDV is a very valuable tool in the differential diagnosis of PN and MD.

Abnormal locomotor muscle recruitment activity is present in horses with shivering and Purkinje cell distal axonopathy.

BACKGROUND: Cerebellar Purkinje cell axonal degeneration has been identified in horses with shivering but its relationship with abnormal hindlimb movement has not been elucidated. OBJECTIVES: To characterise surface electromyographic (sEMG) hindlimb muscle activity in horses with shivering, correlate with clinical scores and examine horses for Purkinje axonal degeneration. STUDY DESIGN: Descriptive controlled clinical study. METHODS: The hindlimb of seven shivering and six control draught horses were clinically scored. Biceps femoris (BF), vastus lateralis (VL), tensor fasciae latae and extensor digitorum longus were recorded via sEMG during forward/backward walking and trotting. Integrated (iEMG) and peak EMG activity were compared between groups and correlated with clinical locomotor exam scores. Sections of the deep cerebellar nuclei (DCN) of six of the seven shivering horses were examined with calbindin immunohistochemistry. RESULTS: In control horses, backward walking resembled forward walking (right hindlimb peak EMG: backward: 47.5 ± 21.9%, forward: 36.9 ± 15.7%) but displayed significantly higher amplitudes during trotting (76.1 ± 3.4%). However, in shivering horses, backward walking was significantly different from forward (backward: 88.5 ± 21.5%, forward: 49.2 ± 8.9%), and resembled activity during trotting (81.4 ± 4.8%). Specific to backward walking, mean sEMG amplitude fell outside two standard deviations of mean control sEMG for ≥25% of the stride in the BF for all seven and the VL for six of the seven shivering horses. Locomotor exam scores were correlated with peak EMG (r = 0.87) and iEMG (r = 0.87). Calbindin-positive spheroids were present in Purkinje axons in DCN of all shivering horses examined. MAIN LIMITATIONS: The neuropathological examination focused specifically on the DCN and, therefore, we cannot fully exclude additional lesions that may have influenced abnormal sEMG findings in shivering horses. CONCLUSION: Shivering is characterised by abnormally elevated muscle recruitment particularly in BF and VL muscles during backward walking and associated with selective Purkinje cell distal axonal degeneration.

Spinal Cord and Peripheral Nerve Abnormalities of the Ruminant.

In food animals, spinal cord damage is most commonly associated with infection or trauma. Antemortem diagnosis is based on clinical signs, history, cerebrospinal fluid analysis, and imaging. As clinical signs are often severe, and prognosis is grave, necropsy may provide a postmortem diagnosis. Peripheral nerve abnormalities are most often the result of trauma. Calving paralysis or paresis is the most common condition affecting the sciatic or obturator nerve and often concurrently involves the peroneal branch of the sciatic. Damage to peripheral nerves is often transient and resolves within a few days as long as the nerve is not severed.

Peripheral neuropathy of a forelimb in horses: 27 cases (2000-2013).

OBJECTIVE To describe the clinical features, diagnostic procedures, management, and outcome of horses with peripheral neuropathy of a forelimb. DESIGN Retrospective case series. ANIMALS 27 horses. PROCEDURES Records from 2000 to 2013 were reviewed to identify horses with peripheral neuropathy of a forelimb. Horses were grouped as having predominant lesions of a suprascapular nerve, axillary nerve, or radial nerve (alone or in association with other brachial plexus nerves) on the basis of physical examination and diagnostic imaging findings. Treatments were primarily conservative. Signalment, history, lameness characteristics, diagnostic imaging features, case management, and outcomes were evaluated. RESULTS Predominant lesions of a suprascapular nerve, axillary nerve, and radial nerve were identified in 11, 2, and 14 horses, respectively. Eight horses with predominant suprascapular nerve injury and 9 with injury to a radial nerve alone or in association with other nerves returned to their previous activity level or intended use after mean recovery periods of 9.3 and 13.3 months, respectively; 2 horses with a predominant axillary nerve injury had this outcome after a mean 3.5-month recovery period. Ultrasonography was useful for evaluation of muscle atrophy and other injuries during the initial examination (in 27 horses) and the rehabilitation period (in 7 horses). CONCLUSIONS AND CLINICAL RELEVANCE Most horses with peripheral neuropathy of a forelimb returned to athletic soundness following an adequate period of rest. Horses with lesions of a radial nerve alone or in association with other nerves typically required longer recovery times than did those with predominant injuries of a suprascapular nerve.

Distribution of feline lymphoma in the central and peripheral nervous systems.

In cats, lymphoma (lymphosarcoma) is the most common neoplasm affecting the spinal cord and the second most common intracranial tumour. Although lymphoma commonly develops in the spinal cord as a part of a multicentric process, a primary form may occur. Lymphoma can exhibit a wide range of morphological patterns, including intraparenchymal brain mass, lymphomatosis cerebri, intravascular lymphoma, lymphomatous choroiditis and meningitis, extradural, intradural-extramedullary or intramedullary lymphoma in the spinal cord, or neurolymphomatosis in the peripheral nerves. Lymphoma may occur as a paraneoplastic disorder associated with peripheral neuropathies. Magnetic resonance imaging (MRI) and computed tomography (CT) are the techniques of choice for morphological assessment of nervous system lesions in vivo. However, biopsy should be performed to achieve a definitive diagnosis. Knowledge of the different morphological patterns expressed by lymphoma in the nervous system of cats allows veterinary clinicians to suspect lymphoma and to arrange appropriate diagnostic procedures, including immunophenotype and clonality studies, along with therapeutic protocols and prognostic evaluations.

Viral neurotropism, peripheral neuropathy and other morphological abnormalities in bovine ephemeral fever virus-infected downer cattle.

OBJECTIVE: This study assessed the neurotropism of bovine ephemeral fever (BEF) virus (BEFV) and described histomorphological abnormalities of the brain, spinal cord and peripheral nerves that may causally contribute to paresis or paralysis in BEF. METHODS: Four paralysed and six asymptomatic but virus-infected cattle were monitored, and blood and serum samples screened by qRT-PCR, virus isolation and neutralisation tests. Fresh brain, spinal cord, peripheral nerve and other tissues were qRT-PCR-tested for viral RNA, while formalin-fixed specimens were processed routinely and immunohistochemically evaluated for histomorphological abnormalities and viral antigen distribution, respectively. RESULTS: The neurotropism of BEFV was immunohistochemically confirmed in the brain and peripheral nerves and peripheral neuropathy was demonstrated in three paralysed but not the six aneurological but virus-infected animals. Wallerian degeneration (WD) was present in the ventral funicular white matter of the lumbar spinal cord of a paralysed steer and in cervical and thoracic spinal cord segments of three paralysed animals. Although no spinal cord lesions were seen in the steer euthanased within 7 days of illness, peripheral neuropathy was present and more severe in nerves of the brachial plexuses than in the gluteal or fibular nerves. The only steer with WD in the lumbar spinal cord also showed intrahistiocytic cell viral antigen that was spatially distributed within areas of moderate brain stem encephalitis. CONCLUSION: The data confirmed neurotropism of BEFV in cattle and documented histomorphological abnormalities in peripheral nerves and brain which, together with spinal cord lesions, may contribute to chronic paralysis in BEFV-infected downer cattle.

Maintenance of arytenoid abduction following carbon dioxide laser debridement of the articular cartilage and joint capsule of the cricoarytenoid joint combined with prosthetic laryngoplasty in horses: an in vivo and in vitro study.

The objective was to evaluate CO2 laser debridement of the cricoarytenoid joint (CAJ) combined with prosthetic laryngoplasty to prevent post-operative loss of arytenoid abduction in seven horses. Horses were assigned to either laser debridement of the left CAJ and laryngoplasty (laser treated, n=5) or control laryngoplasty (sham, n=2), and were evaluated with endoscopic examinations and measurement of right to left angle quotients (RLQ) to assess maintenance of arytenoid abduction. The animals were euthanased at intervals after surgery and larynges were harvested for post-mortem testing, including determination of translaryngeal flow, pressure, impedance and RLQ. Measurements were obtained under increasing vacuum-generated negative pressure with laryngoplasty sutures intact and with the knot/crimp of the laryngoplasty sutures removed. Following post-mortem testing the cricoarytenoid joints were examined histologically. Post-operative endoscopic examinations revealed no significant differences between RLQ measurements calculated for day 1 following surgery to the termination date of the study for the seven horses. Post-mortem RLQ at airflows of 10 and 60 L/s was significantly higher in sham than in laser treated horses both before and after knot/crimp removal. Translaryngeal impedance at 10 and 60 L/s was not statistically different between groups. Histopathology revealed necrosis and loss of articular cartilage in the laser treated horses. The lymphoid cell infiltration subsided but joint capsule and periarticular fibrosis increased over the course of the study. Post-operative loss of arytenoid abduction after laryngoplasty can be minimized with CO2 laser debridement of the CAJ joint.

A histopathological study of bovine ganglia.

One hundred and sixty-eight ganglia from 54 cattle aged 10 days to 10 years were examined microscopically. Samples from six autonomic ganglia and one sensory ganglion were represented. Thirteen animals were clinically normal and 41 were submitted for post-mortem examination. Neuronal vacuolation, spheroid formation, lipofuscin accumulation and central chromatolysis were observed sporadically and were of varying magnitude. Neuronal vacuolation and spheroid formation were not age-related changes, while lipofuscin accumulation was more common in older animals and central chromatolysis was more common in younger cattle. Non-suppurative inflammation and neuronophagia were also common findings (23 out of 54 animals, 42.6%) in autonomic ganglia that did not contain herpesvirus DNA as determined by polymerase chain reaction. Renaut bodies, features of peripheral nerves, were most commonly noted in the vagus. None of the histopathological findings were related to any particular disease in which loss of autonomic nervous system function might be expected. Furthermore, all changes were as common in clinically normal animals as in animals with disease.