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Biomedical subjects

S K Liu

Publications and source records attributed to S K Liu.

At least 91 records · Page 5Linked to original sources

Mediastinal parathyroid adenocarcinoma in a dog.

A tumor in the anterior mediastinum was found in an adult male German Shorthaired Pointer. The dog presented with hypercalcemia that varied with the removal and recurrence of the tumor. The neoplasm was characterized by an encapsulated multilobed grey-white soft mass with stroma, and the recurrent tumor infiltrated veins and the heart. The tumor consisted of groups of clear cells with well outlined cytoplasmic boundaries separated by thin vascular stroma. These cells had few organelles, scattered clumps of glycogen, clear cytosol and prominent infolding and interdigitating plasma membranes and desmosomes. The clinical, light and electron microscopic features were consistent with a functional neoplasm of parathyroid tissue origin.

Adenocarcinoma↗

Canine medullary carcinoma of the thyroid.

An 8-year-old male Irish Terrior dog and a male St. Bernard dog each had a thyroid medullary carcinoma. The first dog was hypocalcemic before removal and with recurrence of the neoplasm. In both dogs the neoplasms were bilateral and microscopic metastases were seen only in the regional lymph nodes. Both neoplasms were characterized by a solid alveolar pattern separated by thin vascular stroma or a linear festoon-like arrangement with thick stroma. The neoplastic cells varied little and were polygonal or round with abundant pale eosinophilic and finely granular cytoplasm. There was little mitotic activity. Both carcinomas contained amyloid. Electron microscopically, the neoplastic cells had moderate nuclear pleomorphism, well developed Golgi complexes, and characteristic membrane-bound electron-dense secretory granules. In some sections, the secretory granule membranes were fused to the cytoplasmic membrane and the granules were in the extracellular space. In one carcinoma there were linear fibrillar structures with an average width of 7.8 nanometers similar to that of amyloid fibrils.

Animals↗

Primary myocardial disease in the cat. A model for human cardiomyopathy.

Thirty-four cats with primary myocardial disease were studied. The cats were divided into two groups, depending on the clinical, hemodynamic, angiocardiographic, and pathologic findings. Group A consisted of those cats with hypertrophic cardiomyopathy and Group B consisted of those cats with congestive cardiomyopathy. Similarity in the characteristics of cardiomyopathy in the human cat was found. Both Group A and Group B consisted predominantly of mature adult male cats. The most common presenting signs were dyspnea and/or thromboembolism, systolic murmurs with gallop rhythms on auscultation, cardiomegaly with (Group A) or without (Group B) pulmonary edema, abnormal electrocardiograms, elevated left ventricular end diastolic pressures, and angiocardiographic evidence of mitral regurgitation with left ventricular concentric hypertrophy (Group A) or left ventricular dilatation (Group B). Some cats in Group A also had evidence of left ventricular outflow obstruction. The principal pathologic findings in these cats were left atrial dilatation, symmetric hypertrophy or asymmetric septal hypertrophy of the left ventricle (Group A), and dilatation of the four cardiac chambers (Group B). Aortic thromboembolism was commonly observed in both groups. These clinical and pathologic findings indicate that cardiomyopathy in the cat is similar to the two most common forms of cardiomyopathy in the human (hypertrophic cardiomyopathy, with and without obstruction, and congestive cardiomyopathy).

Age Factors↗

Dysplasia of the tricuspid valve in the dog and cat.

Dysplasia of the tricuspid valve in 14 dogs and 13 cats was studied. The clinical, electrocardiographic, radiographic, hemodynamic, angiocardiographic, and pathologic findings were reviewed in each species. Alterations of the tricuspid valve complex included long, thick septal leaflets adhered to the septum; absent or short, stout fused chordae tendineae; hypertrophic fused papillary muscles; insertion of papillary muscles directly into the lateral leaflets; incomplete development of the valvular tissue; and enlargement of the right atrium and ventricle. Additional intracardiac anomalies included malformation of the mitral valve complex (5 dogs and 3 cats), ventricular septal defect (3 dogs and 3 cats), pulmonary stenosis (1 dog and 1 cat), aortic stenosis (1 dog and 1 cat), and persistent left cranial vena cava (1 dog).

Animals↗

Feline intestinal adenocarcinoma. A clinicopathologic study of 22 cases.

Twenty-two cases of intestinal adenocarcinoma were diagnosed in an 11-year survey of 3145 feline necropsies. Histologically, tumors were grouped into four classes: (1) carcinoma with solid groups of cells, (2) adenocarcinoma with solid and acinar cells, (3) papillary adenocarcinoma, and (4) mucinous adenocarcinoma. Tumors were commonest in the ileum. Connective tissue, as well as epithelial metaplasia, were associated more often in this group of intestinal adenocarcinomas nomas than seen before. Hypertrophy and hyperplasia of muscular layers of the unaffected sections of intestines were seen in most of the small bowel and in half of the large bowel carcinomas in this series.

Adenocarcinoma↗

Calcifying aponeurotic fibroma in a dog.

A calcifying aponeurotic fibroma involving the soft tissue and bone of the occipital area compressed and attenuated the cerebellum and brainstem of a 9-year-old female dog of mixed breeding. Clinical signs included a head tilt to the left; gait ataxia; anisocoria, with a midly dilated left pupil; horizontal nystagmus, with the fast phase to the right; and a mild depression of the level of consciousness. The signs were sequential and progressive.

Animals↗

Nonhematopoietic neoplasms in cats.

In a study of 3,145 feline necropsies conducted for 11 years by the pathology department of The Animal Medical Center, 289 tumors of nonhematopoietic origin were found in 264 cats. Malignant and epithelial tumors were more common than benign or mesenchymal tumors in all ages and breeds, and in both sexes. They were also more common in female cats than in males, even after mammary neoplasms were excluded. Analysis of groups of tumors according to their tissue of origin indicated some sex and breed dispositions not observed before. Pulmonary carcinomas and osteosarcomas were more frequent in domestic short haired cats than in other breeds, whereas intestinal carcinomas occurred more often in Siamese cats. Female predominated in pulmonary carcinomas, hemangiosarcomas, osteosarcomas, and squamous cell carcinomas, but males outnumbered the females in intestinal carcinomas.

Age Factors↗

Leiomyoma of the tunica vaginalis in a dog.

A benign neoplasm of smooth muscle origin was found in the tunica vaginalis testis of a 13-year-old male Miniature Poodle. The leiomyoma had caused hydrocele and atrophy of the corresponding testis. It consisted of bundles of interwoven smooth muscle cells with elongated nuclei and areas of hyalinization.

Animals↗

Lesions of the conduction system in the cat with cardiomyopathy.

Degeneration and fibrosis of the atrioventricular nodal tissue and left bundle branch, associated with cartilage of bone in the central fibrous body and fibrosis of the interventricular septal crest, were observed in 63 cats with cardiomyopathy. The cardiac lesions consisted of endocardial and myocardial fibrosis or organized endomyocarditis. Electrocardiographic, radiographic, angiocardiography, and hemodynamic changes were also observed in the cats.

Animals↗

Feline cardiomyopathy.

Cardiology was diagnosed by means of clinical, radiographic, electrocardiographic phonocardiographic, angiocardiographic, and pathological findings in 271 or 3,745 cats necropsied from January 1962 to April 1974. The affected cats can be divided into three groups on the basis of the gross and microscopic pathological lesions: 1)endocarditis and myocarditis in 20 young cats; 2)endomyocardial fibrosis and left ventricular hypertrophy in 182 cats; and 3)myocardial degeneration and biventricular dilatation in 69 cats. Of 271 affected cats, thromboembolus was observed in the aorta, and in the carotid, femoral, iliac, renal, pulmonary, and hepatic arteries in 104 instances. The important aspects of cardiomyopathy in cats appears to be the reduced diastolic compliance of the thick left ventricle, resulting in poor fillin. Resistance to ventricular inflow raises the diastolic pressure and causes compensatory left atrial enlargement. A pathogenesis for the onset of clinical signs at any stages as the cause of the heart disease is postulated on the basis of stress causing tachycardia and poor left ventricular filling. Acute left-sided failure with pulmonary edema may be precipitated. Approximately one-fourth of the cats have enlargement of all cardiac chambers, typical of congestive cardiomyopathy. On the basis of the close similarily to cardiomyopathy in man, the cat could serve as a suitable animal model for a conservation of time and effort in the attack against this disorder. There is a need for coordinated research programs for utilizing the multiple avenues of approach such as: epidemiological, clinical, biochemical, pathological, ultrastructural, virological, and immunological.

Angiocardiography↗