Ronald K. Myers

Multinodular pulmonary fibrosis in five horses

CASE DESCRIPTION 5 horses were evaluated because of decreased appetite, weight loss, fever, cough, tachypnea, and respiratory distress. CLINICAL FINDINGS Tachycardia, tachypnea, increased respiratory effort, lethargy, fever, poor body condition, and nasal discharge were detected in various combinations on initial physical examination. Evaluation of the lower portion of the respiratory tract via radiography and ultrasonography revealed a severe nodular interstitial pattern. Histologic examination of lung tissue revealed interstitial expansion of alveolar parenchyma with collagen, intraluminal accumulation of neutrophils and macrophages within the alveoli, and occasional intranuclear inclusion bodies within alveolar macrophages. Equine herpesvirus type 5 was detected in samples of lung tissue, bronchoalveolar lavage fluid, or both via polymerase chain reaction assay in all cases. A diagnosis of equine multinodular pulmonary fibrosis (EMPF) was established. TREATMENT AND OUTCOME Horses were provided supportive treatment and were administered a variety of medications including corticosteroids and acyclovir. Two horses survived and returned to their previous level of activity. Three horses were euthanized because of either deterioration of clinical condition (n=2) or failure to improve within 4 weeks of initiation of treatment (1). CLINICAL RELEVANCE EMPF should be considered as a differential diagnosis for adult horses with interstitial pneumonia and should be suspected on the basis of characteristic radiographic, ultrasonographic, and histopathologic findings. Equine herpesvirus type 5 is found in association with EMPF; although the exact pathogenic role this virus plays in EMPF is unknown, equine herpesvirus type 5 may be an etiologic agent or cofactor in the development of EMPF.

Effects of α‐tocopherol, phenobarbital, and butylated hydroxyanisole during promotion of diethylnitrosamine‐initiated rat hepatocarcinogenesis

The promotion-suppressing ability of two antioxidants was measured to determine the role of oxidative stress in hepatocarcinogenesis. Four-day-old female F344/N rats were dosed with diethylnitrosamine (10 mg/kg). After weaning, they were fed semipurified diets with and without 500 ppm alpha-tocopherol, or the same two diets containing 500 ppm phenobarbital, or 5,000 ppm butylated hydroxyanisole (BHA) for 3 or 11 months. By 11 months, phenobarbital-fed groups had eaten 30% more than other groups did (p less than 0.05), suggesting a role for increased caloric intake in phenobarbital promotion. Phenobarbital and BHA significantly reduced body weights and increased liver weights compared with control rats. After three months, alpha-tocopherol significantly suppressed mean volume of placental glutathione S-transferase (PGST)-positive altered hepatic foci (AHF), regardless of xenobiotic treatment. Phenobarbital increased and BHA decreased the numbers of AHF compared with those of the control group. After 11 months, mean focal volume was significantly suppressed by BHA compared with that of the control group, and phenobarbital increased the total volume of AHF [PGST-positive plus gamma-glutamyltransferase (GGT)-positive AHF] compared with rats fed either control or BHA diets. BHA treatment also increased hepatic glutathione levels by 40% compared with control and rats fed phenobarbital. In conclusion, alpha-tocopherol had only a slight, early effect to suppress promotion of hepatocarcinogenesis. BHA suppressed some indices of promotion at both times and increased hepatic glutathione; however, BHAs toxicity (which suppressed body weight) may also be a factor in its supposable promotion-inhibitory effects.

Toxicity evaluation of polymeric ferric sulphate

Toxicity evaluation of water treated with polymeric ferric sulphate (PFS), an aluminium-free coagulant, was conducted in this research. Six-week old male F344/N rats exposed to PFS-treated water for three months did not show any obvious pathology as observed histologically or in clinical chemistry compared to rats given tap water. There was no significant difference in body weight gain in the rats drinking PFS-treated water compared with rats drinking tap water between five and eight weeks of treatment. Prolonged exposure to PFS-treated water is warranted to elucidate further the possible toxicity of aluminium-free coagulant.

Extracutaneous neutrophilic inflammation in a dog with lesions resembling Sweet's Syndrome

A 7-year-old-spayed female standard poodle dog presented to the Iowa State University Veterinary Teaching Hospital with an 8-day history of lethargy, left hind limb lameness, ptyalism and peripheral lymphadenomegaly. On physical examination, the dog was lethargic, febrile (40.5 degrees C) and had multifocal to coalescing erythematous papular to pustular eruptions on the skin of all four limbs, periocularly and on the ventral and lateral thorax and abdomen. Histopathological findings from skin biopsies of the papules revealed a severe diffuse neutrophilic dermatitis with sub- and intra-epithelial pustules. Four days after being admitted the dog died from cardiac and respiratory failure. At necropsy, in addition to the multifocal to coalescing erythematous papules, the skin contained scattered pustules. Additionally, the subcutaneous tissue surrounding the right stifle was diffusely oedematous, and the peripheral and visceral lymph nodes were enlarged. The predominant histologic lesion was neutrophilic inflammation, in the absence of detectable bacteria in the skin, heart, lungs, oesophagus and left tarsus. In the absence of neoplasia or bacteraemia, a syndrome similar to Sweets Syndrome should be considered as a differential diagnosis in dogs with cutaneous and extracutaneous neutrophilic infiltrates.

Comparative Histologic Effects of Daily Topical Application of Creams Containing All-trans-Retinoic Acid or All-trans-Retinoyl β-Glucuronide on Pig Skin

The efficacy of all-trans-retinoic acid (tRA) and all-trans-retinoyl β-glucuronide (RAG), a water-soluble metabolite of vitamin A, in the topical treatment of acne is comparable. However, whereas 3.3 mM tRA shows side effects, 3.3 mM RAG does not. To assess the relative toxic and histologic effects (dermal and epidermal changes) of long-term (24-week) daily applications of tRA and RAG on the skin, separate skin patches were measured and marked dorsally on the skin of six 21-day-old, castrated male pigs. Each skin patch area was treated daily with a cream formulation containing either 3.3 mM RAG, 16.5 mM RAG, 33 mM RAG, 3.3 mM tRA, 16.5 mM tRA or blank cream. To serve as controls, one patch received no treatment, one patch received blank cream only and for 5.3 weeks one ‘washed’ patch was given daily application of 33 mM RAG with routine cleansing using a mild soap typical of skin care. The amount of cream used per square centimeter remained the same during the course of the study. Biopsy tissue was collected at –1, 0, 2, 4, 8, 12 and 24 weeks from 7 test patches. The ‘washed’ patch was biopsied once at the 5.3-week mark. Topically applied RAG cream (3.3 mM) resulted in significantly lower histologic scores when compared with scores from tissue treated with an equimolar concentration of tRA. The highest concentration of RAG tested (33.3 mM) resulted in a response comparable to that observed in the lowest tRA (3.3 mM) treated patch area. Daily cleansing of the test area receiving 33.3 mM RAG completely eliminated any clinical signs or negative histologic changes. In conclusion, long-term topical tRA treatment in young pigs, as in humans, showed dose-dependent adverse effects on the skin, whereas RAG treatment had significantly lower histologic changes and less irritation and/or inflammation.

Episodic blindness and ataxia in a horse with cholesterinic granulomas.

An 11-year-old Oldenburg mare presented following three episodes of acute, transient blindness, ataxia, and disorientation within the preceding 7 months. Clinical improvement, including return of vision, occurred within 1 week of initiating corticosteroid therapy for each of the three episodes. However, mild right-sided miosis was a consistent finding on ophthalmic examinations. Routine clinicopathologic testing revealed no significant abnormalities, and testing of cerebral spinal fluid for selected infectious diseases was unrewarding. Computed tomography of the brain demonstrated a hyperattenuating mass with peripheral mineralization in the rostroventral aspect of each lateral ventricle. The mare was euthanized due to a guarded to poor prognosis. On histopathology, the masses consisted of clusters of cholesterol clefts admixed with leukocytes, mineral deposits, and connective tissue. Cholesterinic granulomas of the lateral ventricles and hydrocephaly were diagnosed. Cholesterinic granulomas should be considered a differential diagnosis in horses presenting for intermittent blindness.

Uptake of ferritin and Bordetella avium in bronchus-associated lymphoid tissue of turkeys

The uptake of macromolecular and particulate materials in bronchus-associated lymphoid tissue (BALT) in turkeys was examined using transmission electron microscopy. Tracer materials used were live and ultraviolet-killed (UV-killed) Bordetella avium and ferritin. Suspensions of bacteria and ferritin were instilled via intratracheal catheterization and allowed to remain in contact with the respiratory surfaces for 0, 10, 30, 60, 90, and 120 min. Ferritin and B. avium were taken up by both ciliated and non-ciliated cells of the epithelium overlying BALT (BALT epithelium). Ferritin was found in organelles associated with endocytosis (i.e. apical vesicles, endosomes, cytoplasmic vacuoles) and was apparently transported across epithelial cells, since it was also found in intercellular spaces. Bacteria were found in vacuoles within BALT epithelial cells, but not free in intercellular spaces. Some macrophages in BALT epithelium also contained bacteria. No differences were observed between uptake of live and UV-killed bacteria. We conclude that both ciliated and non-ciliated cells of BALT epithelium in turkeys are able to take up macromolecular and particulate materials. Bacteria are also accessible to intraepithelial macrophages, although whether they are taken up directly from the bronchial surface or whether they pass through epithelial cells first could not be determined. This evidence suggests that antigens, including respiratory pathogens, could gain access to cells of the avian immune system by transepithelial passage in BALT.