Cytology of polychrome-stained equine synovial fluid smears. Comparison with clinical findings, histologic specimens, Wright-Giemsa-stained smears and outcome.

Polychrome-stained equine synovial fluid specimens from 34 normal joints and 129 joints with clinical abnormalities were examined cytologically. The smears from joints with abnormalities were categorized as within normal limits (4.7%), slight abnormality (27.9%), proliferative synovitis (21.7%), neutrophilic pattern (20.2%), elongated cell pattern (10.1%), other moderate to marked abnormality (11.6%) and unsatisfactory (3.9%). Cytologic abnormalities that were not restricted to a single category included spindle cells, crystals, stellate cells and cartilage fragments. Multinucleate cells and mononucleate cells with dense cytoplasm and a delicate periphery were seen in smears from cases with clinical diagnoses of osteochondrosis or fracture; interpretation of these cells as osteoclasts and their mononucleate precursors was supported by positive staining with tartrate-resistant acid phosphatase. Smears within the same cytologic category were not found to correspond with a single clinical diagnosis. The identification of several cytologic patterns in cases with the same clinical diagnosis suggests that multiple stages of disease were sampled. Except in cases with the cytologic neutrophilic pattern, there was not a consistent relationship between the histologic features in synovial biopsy specimens and the cytologic findings; the morphologic variation within synovial membrane sections and between sections from different locations was sometimes marked. When compared with air-dried, Wright-Giemsa-stained smears, the polychrome-stained smears were more sensitive in the detection of cytologic abnormalities and were less often falsely negative or unsatisfactory. Following surgery, cases with clinical diagnoses of osteochondrosis (29 cases) and fracture (25 cases) were analyzed according to clinical outcome and cytologic category. While 80% of the horses with proliferative synovitis in cytologic specimens were sound, only 67% of those with the elongated cell pattern, 50% of those with slight abnormality and 33% of those with other moderate to marked abnormality were sound. A statistically significant relationship (P less than .02) was found in cases with a diagnosis of osteochondrosis: animals with a proliferative synovitis pattern were almost three times as likely to be sound as compared to those with slight abnormality. These findings indicate that polychrome-stained equine synovial fluid smears (1) provide information that is different from that found in corresponding histologic sections and (2) are superior to air-dried, Wright-Giemsa-stained smears for cytologic examination. The polychrome-stained equine synovial fluid smears were found to provide information supportive of clinical, radiographic and prognostic data.

Variation in glycogen and mucins in the equine uterus related to physiologic and pathologic conditions.

Histochemical stains were applied to six equine uterine biopsies representative of the physiologic breeding season, Spring and Fall transition, and Winter anestrus periods. These were compared with uterine biopsies from six mares with intrauterine urine pooling, eight mares used to study the uterine response to indwelling catheterization, and necropsy specimens from four pregnant mares at approximately 60 or 100 d of gestation. Alcian blue staining at pH 2.5 or 1.0 was used to identify the presence of carboxylated and sulfated acid mucins or only suflated acid mucins, respectively. Periodic acid-Schiff staining was used to identify neutral mucosubstances or glycogen, with or without prior diastase digestion. The uterine glands contained glycogen, which was most abundant during the physiologic breeding season. The luminal epithelial cells during the physiologic breeding season and Spring and Fall transition contained predominately carboxylated acid mucins. Carboxylated acid mucin secretion also was stimulated by indwelling catheterization and intrauterine urine pooling. It is hypothesized that secretion of carboxylated acid mucins by the endometrial epithelium may be elicited by hormonal or irritative/inflammatory stimuli, and it may be a protective response.

"Repair cells" in equine uterine cytologic and histologic specimens.

Cells resembling those known as "repair cells" in gynecologic cytology specimens from women were identified in uterine cytology specimens from infertile mares treated with antibiotics using indwelling uterine catheters. This prompted a study of the effect on the equine uterus of indwelling catheterization without antibiotic infusion, using light microscopic examination of cytologic and biopsy specimens and electron microscopic examination of biopsy specimens. Cytologic and biopsy specimens had features within normal limits at the start of the study. Following five days of indwelling catheterization, neutrophils were present in both cytologic and biopsy specimens. In cytologic specimens, numerous groups of "repair cells" were present; similar cells in biopsy specimens indicated this was a focal reaction. The large nuclei and prominent nucleoli of the "repair cells" suggested cellular proliferation or regeneration. However, this was contradicted by the ultrastructural sparsity of ribosomes, endoplasmic reticulum, Golgi apparatus and mitochondria. Inflammation and "repair cells" were not present in cytologic or biopsy specimens collected 40 days after the start of the study. Although these cells may be a component of a repair process, our results support the hypothesis that "repair cells" in human and equine gynecologic cytology specimens are injured, rather than regenerating, cells. The term dysphaneroplastic (Greek: "abnormal cytosol development") is proposed to describe these cells since the cytoplasm does not reflect the features of cellular activity suggested by the nuclear appearance.

Inclusions in equine cytologic specimens.

Inclusions and cellular changes were seen in cytologic specimens from 1 healthy horse, 6 horses hospitalized because of respiratory problems, and 1 horse hospitalized because of colic and hepatitis. Two bronchial aspirates contained detached ciliated cytoplasmic tufts and cytoplasmic inclusions characteristic of the specific degenerative process called ciliocytophthoria. These changes and inclusions resembled those seen in bronchial aspirates from human beings with parainfluenza virus infection. Four bronchial aspirates and 2 serous fluid specimens had nuclear inclusions resembling those seen in a variety of specimens from human beings with herpetic infections. The abnormalities and inclusions were similar to changes seen in cell monolayer and suspension cultures infected with equine herpesvirus type 1.

Eosinophils in equine uterine cytology and histology specimens.

In a review of specimens from 80 mares with concurrently collected endometrial biopsy and cytology preparations, eosinophils were found in 33 specimens from 27 mares. In 22 of 27 mares, there were conditions predisposing to pneumovagina, which presumably led to pneumouterus. Thirty-two of the 80 mares also had conditions predisposing to pneumovagina but no eosinophils in the uterine specimens. Experimental introduction of air into the uterus of 3 mares resulted in eosinophils in their uterine specimens.