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Biomedical subjects

A K Patnaik

Publications and source records attributed to A K Patnaik.

At least 19 recordsLinked to original sources
PubMed1992

Malignant anterior uveal melanoma with diffuse metastasis in a dog.

Enucleation was performed in 10-year-old sexually intact female mixed-breed German Shepherd Dog. Histologic examination revealed that the dog had an uveal amelanotic melanoma of the eye. The tumor consisted of anaplastic cells with a high mitotic index, indicating malignancy. On examination 3 months after enucleation, the dog had difficulty breathing and nasal discharge. Radiography revealed pulmonary metastasis. The dog was euthanatized. Necropsy revealed diffuse metastasis involving various organs.

Animals↗
PubMed1992

Nonhematopoietic hepatic neoplasms in cats: 21 cases (1983-1988).

Nonhematopoietic hepatic neoplasms (n = 25) were diagnosed in 21 cats during a 5.5-year period. Thirteen of the neoplasms were benign bile duct adenomas and 12 were malignant, 6 of which were bile duct adenocarcinomas. All cats were greater than or equal to 10 years old, and 14 were male. Main clinical signs were anorexia and lethargy, and 15 of 21 cats had hepatomegaly. All 21 cats were feline leukemia virus-test negative. Although there was a trend toward high activities of serum alanine transaminase and aspartate transaminase, neither clinical signs nor enzyme activity were specific for diagnosis of hepatic neoplasia in the cats of this study.

Adenoma, Bile Duct↗
PubMed1992

Leiomyosarcoma in dogs: 44 cases (1983-1988).

During a 5-year period, leiomyosarcoma was diagnosed in 57 dogs. Forty-four dogs were included in the study on the basis of completeness of medical records. All dogs underwent exploratory laparotomy, and dogs were allotted to 4 groups according to primary site of tumor: spleen (16 dogs, median age 10.3 years), stomach/small intestine (13 dogs, median age 10.3 years), cecum (10 dogs, median age 11.8 years), and liver (5 dogs, median age 9 years). All dogs with leiomyosarcoma of the liver had visible metastasis and were euthanatized at surgery. In the other 3 groups, 79% of the dogs had no gross evidence of metastasis at surgery, and 64% survived greater than 2 weeks. Median survival in these 3 groups was 10 months (range, 1 month to 7 years); 48% died of metastasis, 32% died of unrelated causes, and 16% died of unknown causes. The prognosis in dogs with leiomyosarcoma of the spleen, stomach, small intestine, and especially the cecum is good to excellent if surgery is performed. In dogs with leiomyosarcoma of the liver, the prognosis is poor.

Animals↗
PubMed1992

Pancreatic adenocarcinoma with metastasis in two ferrets.

Exocrine pancreatic adenocarcinoma with carcinomatosis was diagnosed in 2 ferrets. Clinical signs included abdominal distention and hind limb weakness. Ultrasonography revealed moderate ascites in both ferrets, an irregular abdominal mass in 1 ferret, and multiple abdominal masses in the other ferret. The ferrets were euthanatized, and necropsy of 1 ferret revealed carcinomatosis without visceral metastasis.

Adenocarcinoma↗
PubMed1992

A morphologic and immunocytochemical study of hepatic neoplasms in cats.

A retrospective study was done of 47 neoplasms of the hepatic and biliary systems from 47 cats brought to The Animal Medical Center over a period of 10 years (1980 to 1989). Histologic examination of specimens taken at necropsy revealed that 87% (41/47) of the hepatic neoplasms were epithelial and 13% (6/47) were nonepithelial. Of the epithelial tumors, 25/47 (53%) were of intrahepatic bile duct origin, 9/47 (19%) were of hepatocellular origin, 5/47 (11%) involved the extrahepatic bile ducts, and 2/47 (4%) were adenocarcinomas of the gall bladder. Of the nonepithelial neoplasms, hemangiosarcomas were more common, 5/47 (11%), than leiomyosarcomas, 1/47 (2%). Multiple liver lobes were involved in 21/34 (62%) of the epithelial and all six of the nonepithelial intrahepatic neoplasms. Most of the bile duct adenocarcinomas (6/9) were predominantly characterized by acinar structures with mucin production, diffuse necrosis, and little desmoplasia. The hepatocellular carcinomas were characterized by three patterns-trabecular (five tumors), pseudoglandular pattern (two tumors), and anaplastic (one tumor). The hepatic carcinoid was characterized by various-sized groups of acinar and rosettelike structures, some with lumens, separated by thin fibrovascular stroma. The extrahepatic bile duct adenocarcinomas (4/4) were acinopapillary with moderate desmosplasia, whereas the adenocarcinomas of the gall bladder had elongated tubular structures lined by anaplastic cells and a severe desmoplastic reaction. The neuroendocrine carcinoma of the extrahepatic bile duct, the hemangiosarcomas, and the leiomyosarcoma had morphologic features characteristic of these neoplasms. Two of the 16 (13%) bile duct adenomas had anaplastic and precancerous changes. Residual benign components were seen in 10/15 (67%) of the biliary adenocarcinomas, 4/9 (44%) of the intrahepatic bile duct adenocarcinomas, and all of the extrahepatic bile duct adenocarcinomas and gall bladder adenocarcinomas. Results of immunohistochemical studies of the biliary neoplasms were similar to those described in studies of biliary neoplasms in human beings. Results of this study revealed that the frequency of different types of hepatic neoplasms in cats varied from that seen in dogs and human beings, but the morphologic features were comparable.

Animals↗
PubMed1991

Gross, histologic, cytochemical, and immunocytochemical study of medullary thyroid carcinoma in sixteen dogs.

The gross, histomorphologic, cytochemical, and immunocytochemical findings in 16 dogs with medullary thyroid carcinoma were evaluated. Grossly, the neoplasms were encapsulated, firm, lobulated, and grey-white to tan. The typical histologic pattern was groups or sheets of round to polygonal cells with fibrovascular stroma, which was thickened and hyalinized in places. Variants of clear cell (two dogs), giant cell (one dog), and oxyphil cell (one dog) types were also seen. In all 16 dogs, Grimelius-stained sections of the neoplasms revealed intracytoplasmic silver granules; ten tumors contained amyloid and four contained mucin. Immunohistochemically, the neoplasms reacted to AE1/AE3 (n = 13), S-100 protein (n = 5), neuron specific enolase (n = 14), synaptophysin (n = 11), calcitonin (n = 16), somatostatin (n = 4), gastrin (n = 7), and serotonin (n = 6). Only one neoplasm was positive for vimentin. None of the neoplasms reacted to antibodies for neurofilaments, thyroglobulin, insulin, glucagon, or adrenocorticotrophic hormone. Eleven neoplasms contained multiple (two to four) peptides, in various combinations. It was concluded that in dogs, gross and histologic features can be used to distinguish medullary thyroid carcinoma from other thyroid malignancies. Cytochemical and immunocytochemical studies with neuron specific enolase, synaptophysin, and calcitonin can be used to establish the diagnosis of medullary thyroid carcinoma in dogs.

Animals↗
PubMed1990

Lymphomas in dogs. A morphologic, immunologic, and clinical study.

One hundred seventy-six canine lymphomas were classified morphologically using four of the major human lymphoma classification schemes (Rappaport, Lukes-Collins, Kiel, and the Working Formulation). All 176 dogs received the same chemotherapeutic protocol. Sixty-two of these lymphomas had their immunophenotypes established by examination of cell surface markers by automated cytofluorography. Several different morphologic types of canine lymphoma were identified and these were comparable to morphologic categories in human classification schemes. Follicular and low grade lymphomas were rare. The two most common morphologic types were diffuse large cell (centroblastic) and immunoblastic. The Kiel classification appeared to be the most useful human scheme for classifying the canine lymphomas. Cytofluorographic analysis was generally straightforward, and 60 of the 62 lymphomas were placed into one of three immunophenotypic categories: 27 pan-T(LQ1)+SIg+, 21 pan-T(LQ1)-SIg+, and 12 pan-T(LQ1)+SIg-. Two of the lymphomas could not be characterized immunologically because a pre-existing or reactive non-neoplastic population of lymphocytes made interpretation of single cell suspension analysis difficult. The authors identified correlations between morphology and survival and disease-free remission; dogs with high-grade tumors generally survived the longest and had the longest remissions. No correlations were identified between high concentrations of serum lactate dehydrogenase, age, sex, or stage of disease, and morphology, immunophenotype, remission, or survival times. A significant correlation between clinical illness and survival time was documented. The median age of the dogs was nine years, no significant effect of sex on prevalence was observed, and some breeds were significantly overrepresented. Significant morphologic-immunophenotypic correlations included shorter remission and survival times for T-cell tumors than B-cell tumors, and a highly significant correlation between the pan-T(LQ1)+SIg-"T cell" phenotype and hypercalcemia.

Animals↗
PubMed1990

Extra-adrenal pheochromocytoma (paraganglioma) in a cat.

Extra-adrenal pheochromocytoma (paraganglioma) arising from periadrenal tissue was diagnosed in an 18-year-old spayed domestic shorthair cat. The tumor was palpable on physical examination, but not apparent on plain radiographs. The cat developed temporary cardiac arrhythmia while the mass was being handled during excision, suggesting that the tumor was functional. The tumor was characterized histologically by nests and sheets of neoplastic cells separated by thin, vascular stroma. The cells had abundant eosinophilic granular cytoplasm and prominent nuclei. Diffuse, dark, intracytoplasmic granules were seen in sections stained with Grimelius stain. Ultrastructurally, the cells contained round and oblong, membrane-limited, dense core neurosecretory-type granules. Serotonin was detected in the cytoplasm of the neoplastic cells by use of immunocytochemical analysis.

Adrenal Gland Neoplasms↗
PubMed1990

Canine extraskeletal osteosarcoma and chondrosarcoma: a clinicopathologic study of 14 cases.

Canine extraskeletal osteosarcomas are extremely rare tumors. Over a period of 25 years at the Animal Medical Center, approximately 1,000 cases of skeletal osteosarcomas have been diagnosed. During the same period 11 cases of extraskeletal osteosarcomas and three extraskeletal chondrosarcomas were diagnosed. Tumors of the mammary gland were excluded. Extraskeletal osteosarcomas were found in the adrenal gland, eye, gastric ligament, ileum, kidney, liver, spleen, testicle, and vagina. The chondrosarcomas were found in the mitral valves, lungs, and omentum. The mean age of the dogs with extraskeletal osteosarcoma was 11 years, and the mean age of the dogs with extraskeletal chondrosarcoma was 14 years. The The sizes of the tumors ranged from 3 cubic centimeters to 8,315 cubic centimeters. Osteoblastic osteosarcomas were the most common histologic type (7/11, 63.6%); there was a single case of each of the following: fibroblastic, fibrous histiocytic, chondroblastic, and mixed osteo-chondroblastic osteosarcoma. Two of the dogs with chondrosarcomas had mesenchymal chondrosarcomas involving the lungs and omentum. The remaining dog had a regular chondrosarcoma involving the mitral valve. Distant metastases were present in seven of 11 dogs with extraskeletal osteosarcoma and in none of the dogs with chondrosarcoma. In contrast to human beings, in which most extraskeletal osteosarcomas occur in the soft tissues and the extremities, most canine extraskeletal osteosarcomas develop in the visceral organs.

Animals↗
PubMed1989

Argyrophilic, intracellular bacteria in some cats with idiopathic peripheral lymphadenopathy.

Lymph node biopsy specimens from several previously reported cases of unusual feline peripheral lymphadenopathies were re-examined by a modified Dieterlé silver-impregnation staining technique. In a proportion of these specimens, the Dieterlé stain revealed tiny pleomorphic, intensely argyrophilic coccobacilli. These organisms were predominantly located within macrophages. The infected cells were focally distributed, particularly in the interfollicular regions of the nodes. They were inconspicuous in sections stained by other, more conventional staining methods. It is possible that these coccobacilli represent yet another, previously unidentified, cause of chronic lymph node hyperplasia in the cat.

Animals↗
PubMed1989

Cutaneous plasmacytomas in dogs: a morphologic and immunohistochemical study.

Forty-nine cutaneous plasmacytomas in 46 dogs were studied. Tumors occurred at solitary sites in middle-aged to old dogs (mean age, 9.7 years) and most commonly involved the skin of the digits, lips, and ears. Initial diagnosis was made on the basis of light microscopic morphologic findings. Tumors were graded according to the extent of cellular differentiation and immunoreactivity to a panel of immunohistochemical markers (cytokeratins, canine IgG F[ab]2, neurofilament, neuron-specific enolase, S-100 protein, and vimentin). Immunoreactivity was limited to antibodies directed at canine IgG F(ab)2 and vimentin. Vimentin immunoreactivity was usually greater than that of canine IgG F(ab)2, but there was no correlation between immunoreactivity and histologic grade of the tumors. Thirty-six of 39 dogs (92.3%) followed (mean follow-up, 13 months) were cured by surgical excision. The results of this study indicate that canine cutaneous plasmacytomas are benign neoplasms that should be included in the differential diagnosis of cutaneous round cell tumors in dogs.

Animals↗
PubMed1988

Morphology of canine ovarian Sertoli-Leydig cell neoplasms. A report of 12 cases.

Of 71 dogs with primary ovarian neoplasms, 12 (17%) had Sertoli-Leydig cell tumors. Five dogs had Sertoli-Leydig cell tumors, four had pure Sertoli cell tumors, and three had Sertoli-Leydig cell tumors with a retiform pattern. Variously differentiated Sertoli cells were seen in the Sertoli-Leydig cell tumors, and one of these metastasized to the peritoneum. The pure Sertoli cell tumors were similar to these tumors in male dogs. The retiform pattern in the third group of tumors was characterized by tubuloalveolar structures resembling rete testes. Heterologous elements were seen in seven tumors (58%)--enteric glands in three Sertoli-Leydig cell tumors and one Sertoli-Leydig cell tumor with retiform pattern, and neuroendocrine carcinoma in one pure Sertoli cell tumor and two Sertoli-Leydig cell tumors with retiform pattern. The uterus was examined in seven dogs, and six (87%) had endometrial hyperplasia.

Animals↗
PubMed1988

Small intestinal adenocarcinoma in cats: 32 cases (1978-1985).

The medical records of 32 cats with small intestinal adenocarcinoma were reviewed. Common clinical signs included vomiting, dehydration, weight loss, cachexia, anorexia, and lethargy. In 50% of the cats, an abdominal mass was palpated, and in 38%, a mass was seen on radiographs. Biopsy of the tumor without resection was performed in 9 cats; 8 cats were euthanatized at the time of surgery, 7 because of metastases, and 1 cat died 1 day after surgery. In 23 cats, resection was performed. Eleven of these died within 2 weeks after surgery (mean survival time, 2.6 days); 8 had lymph node metastasis. Twelve cats survived greater than 2 weeks after surgery. The mean survival of 11 of these cats was 15 months. Six cats were euthanatized because of recurrent signs; 5 of the 6 had a recurrent abdominal mass. One cat was alive 2 years after surgery. Results of this study indicated that cats with adenocarcinoma, even those cats with advanced disease, can have long-term survival after surgery.

Adenocarcinoma↗
PubMed1988

Feline melanoma: a comparative study of ocular, oral, and dermal neoplasms.

Melanomas diagnosed in 29 cats over an 11 year period included 19 ocular (16 intraocular, three palpebral), five oral, and five dermal melanomas. Intraocular melanomas involved the ciliary body and iris in 12; the whole eye was involved in four. The average age of cats with intraocular melanomas was 11 years; the female : male ratio was 9 : 7. Histologically, eight intraocular tumors were mixed, six were epithelioid, and two were spindle cell. Ten of 16 cats (62.5%) with intraocular melanomas were killed because of the tumor at a mean of 156 days; four are living with no evidence of disease (average, 255 days). The mean time of death in cats with palpebral melanoma was 409 days. Metastasis occurred in 63% of cats with intraocular melanoma and all cats with palpebral melanoma. Four cats with oral melanoma were killed at a mean of 61 days; all had metastasis. Of five cats with cutaneous melanoma, one was killed with metastasis at 90 days; three cats were alive without evidence of recurrence or metastasis greater than 365 days after surgery. Results of this study indicate that in the cat, ocular melanomas are more common than oral and dermal melanomas, and ocular and oral melanomas are more malignant than dermal melanomas, with higher rates of mortality and metastasis.

Animals↗
PubMed1987

Use of splenectomy in the management of lymphoma in dogs: 16 cases (1976-1985).

Sixteen dogs with lymphoma underwent splenectomy to relieve signs of massive splenomegaly including splenic rupture. The most common preoperative hematologic abnormalities, anemia and thrombocytopenia, were reversed in all dogs surviving the initial postoperative period. Within 6 weeks after surgery, 5 dogs died because of disseminated intravascular coagulation and sepsis. The remaining 11 dogs underwent chemotherapy. These 11 dogs had a complete response rate of 66% at one month after surgery; the mean and median survival times were 9.3 and 5 months, respectively. In 7 dogs evaluated until death, the mean and median survival times were 13.4 months and 14 months, respectively.

Animals↗
PubMed1987

Cerebral astrocytoma in four cats: clinical and pathologic findings.

Cerebral astrocytoma was diagnosed in 4 cats. A long-standing history of seizures followed by an increase in frequency of uncontrolled seizures were prominent features in these cats. Anticonvulsants provided effective seizure control in 3 cats for a period of 1 to 3 years. On initial and subsequent neurologic examinations, all cats were postictal and had focal neurologic deficits. In 2 cats, there were focal EEG patterns consistent with the neuroanatomic diagnosis of the tumor. White blood cell pleomorphism of the CSF was determined in the cats that underwent CSF analysis. Pathologic findings in all cats included tumor necrosis and edema, compression of the opposite hemisphere, and invasion of the third and lateral ventricles.

Animals↗
PubMed1987

Spinal meningiomas in dogs: 13 cases (1972-1987).

Medical records of 13 dogs with spinal meningiomas were reviewed. Breed predilections were not found. Males outnumbered females 9 to 4, and most of the dogs were middle-aged. All dogs had motor deficits of various degrees, and approximately half of the dogs had clinical signs of mild to moderate spinal pain. The remainder had histories of clinical signs suggestive of chronic discomfort. There was a prolonged (greater than 3 months) delay between the onset of signs and diagnosis, except in 3 dogs. The neurologic courses usually were progressive. Results of noncontrast spinal radiography were normal in 10 dogs; in 3 dogs, the lamina appeared scalloped. Results of myelography contributed to the correct diagnosis in 10 of 12 dogs; however, in 2 dogs, intradural/extramedullary tumors were thought to be intramedullary lesions. A preponderance of cervical meningiomas was found, accounting for 10 of 13 tumors. Lumbar meningiomas were found in the remaining 3 dogs. Surgery was performed in 9 of the dogs, six of which improved after surgery. Poor results were correlated with tumors that involved spinal cord segments of an intumescence, ventrally located tumors, iatrogenic trauma, and tumor invasion into adjacent neural parenchyma. Four of 13 spinal meningiomas were found to be invasive into the spinal cord itself.

Animals↗