Biomedical subjects

José A Ramos-Vara

Publications and source records attributed to José A Ramos-Vara.

10 recordsLinked to original sources

PubMed2006

Comparison of two polymer-based immunohistochemical detection systems: ENVISION+ and ImmPRESS.

The non-specific background reaction produced in avidin-biotin-based immunohistochemistry, particularly after harsh antigen retrieval procedures, has promoted the use of non-avidin-biotin systems, yet there are few reports comparing the performance of non-avidin-biotin, polymer-based methods. In this study we compare two of these methods, ENVISION+trade mark and ImmPRESS, in animal tissues. We examined the immunoreactivity of 18 antigens in formalin-fixed, paraffin-embedded tissues. Antigens were located in the cytoplasmic membrane (CD11d, CD18 and CD79a), cytoplasm (calretinin, COX-1, COX-2, Glut-1, HepPar 1, KIT, Melan A, tryptase and uroplakin III) or nucleus (MUM-1, PGP 9.5 and thyroid transcription factor 1). We also evaluated three infectious agents (Aspergillus, calicivirus and West Nile virus). The staining with ENVISION+ or ImmPRESS was performed simultaneously for each antigen. The intensity of the reaction and background staining were scored. ImmPRESS yielded similar or higher reaction intensity than ENVISION+trade mark in 16/18 antigens. ImmPRESS produced abundant background with the other two antigens (calretinin and COX-2), which hindered interpretation of the specific reaction. The cost of ImmPRESS was 25% lower than for ENVISION+trade mark. Based on these results, ImmPRESS is a good polymer-based detection system for routine immunohistochemistry.

Animals↗

PubMed2006

Extraskeletal osteosarcoma associated with retained surgical sponge in a dog.

Retained surgical sponges are usually discovered in the abdominal cavity, sometimes years after the surgical procedure, and the typical reaction is formation of a foreign-body granuloma, often called gossypiboma or textiloma. In this instance, an extraskeletal osteosarcoma, associated with the granulomatous reaction to a retained surgical sponge adjacent to the stifle, was diagnosed in an 11-year-old Labrador Retriever 9 years after repair of a ruptured cranial cruciate ligament. Radiographic detection of linear foreign material in the soft tissue mass was the basis for a diagnosis of gossypiboma. The mass was surgically excised. Histologically, fibers consistent with those of cotton gauze were associated with the granulomatous inflammation and the osteosarcoma. Amputation or radiation therapy was declined; the dog was treated conservatively with doxycycline and deracoxib. Three months after surgical excision, the dog was euthanized because of local recurrence of the mass along with lameness and decreased appetite.

Animals↗

PubMed2006

Hepatic yersiniosis in a cougar (Felis concolor).

A cougar (Felis concolor) was diagnosed with hepatic yersiniosis by bacterial culture and histopathology. The animal had a 2-week history of anorexia and jaundice before its death. Grossly, the liver exhibited caseo-necrotic foci. Histopathologically, there was necrotizing and suppurative hepatitis, with large numbers of intralesional gram-negative coccobacilli. Additional hepatic lesions included central vein thrombosis, lymphoplasmacytic portal hepatitis, and capsulitis. Yersinia pseudotuberculosis coccobacilli were isolated in pure culture from the hepatic lesions. Because the hepatic lesions in this animal resemble those of other zoonotic diseases, such as plague and tularemia, veterinarians and laboratory personnel who handle samples should take adequate safety precautions. This report is the first to describe the pathology associated with hepatic yersiniosis in a cougar.

Animals↗

PubMed2006

Degenerative myelopathy and vitamin A deficiency in a young black-maned lion (Panthera leo).

Degenerative myelopathy and vitamin A deficiency were diagnosed in a 1-year-old, female, black-maned lion (Panthera leo). Diffuse white matter degeneration characterized by dilated myelin sheaths, Wallerian degeneration, and reactive astrocytosis was present at all levels of the spinal cord. With luxol fast blue-resyl echt violet stain, bilaterally symmetrical demyelination was observed in the fasciculus cuneatus of the cervical spinal cord and in peripheral white matter of cervical, thoracic, and lumbar segments. Additionally, the ventral gray columns and brain stem nuclei contained rare chromatolytic neurons with abnormal neurofilament accumulation. Leptomeninges of the cervical spinal cord were focally adhered to the dura and thickened by fibrosis and osseous metaplasia. Vitamin A deficiency was diagnosed based on hepatic vitamin A concentration of 1.71 microg/g dry weight. Adequate hepatic vitamin A concentration for yearling to adult domestic animals ranges between 150 and 1000 microg/g dry weight. Lesions were distinct from those previously described in young captive lions with vitamin A deficiency, which had thickened skull bones and cerebellar herniation. The pathogenesis of vitamin A-associated myelopathy in this lion may be similar to that described in adult cattle, which is believed to result from spinal cord compression secondary to elevated pressure of cerebrospinal fluid.

Animals↗

PubMed2005

Comparison of rabbit monoclonal and mouse monoclonal antibodies in immunohistochemistry in canine tissues.

Rabbit monoclonal (RM) antibodies appear to have higher affinity for antigens than mouse monoclonal (MM) antibodies. However, RM antibodies have not been used in veterinary diagnostic immunohistochemistry. The authors compared reactivities of RM and MM antibodies on formalin-fixed, paraffin-embedded canine tissues, targeting 11 different antigens: CD3, CD79a, calcitonin, calretinin, chromogranin A, COX-2, estrogen receptor, Ki67, progesterone receptor, synaptophysin, and vimentin. Paraffin-embedded tissue sections were processed by 1 of 2 antigen-retrieval methods: 1) proteinase K digestion or 2) steam heat in citrate buffer. An additional set of slides did not receive antigen retrieval. Immunostaining was performed using an automated stainer, and scores were assigned to the different dilutions and antigen-retrieval methods on the basis of staining intensity and number of positive cells. Steam heat was usually the best antigen-retrieval method. The optimal dilution for each antibody was that which resulted in the highest specific staining and the lowest nonspecific (background) staining. The RM or MM antibodies yielded a specific reaction for all antigens examined except calretinin. The RM and MM antibodies yielded a specific reaction for 4 antigens only: COX-2, Ki67, synaptophysin, and vimentin. Three antigens (CD3, chromogranin A, and progesterone receptor) were detected only with RM antibodies, whereas the other 3 (CD79a, calcitonin, estrogen receptor) were detected only with MM antibodies. The results of this study differed from those reported for human tissues by the manufacturers of the antibodies. These results emphasize that, regardless of manufacturers' recommendations, each antibody must be individually standardized and validated before routine use in canine tissues.

Animals↗

PubMed2005

Effects of delayed or prolonged fixation on immunohistochemical detection of bovine viral diarrhea virus type I in skin of two persistently infected calves.

The effects of delayed or prolonged fixation on immunohistochemical detection of bovine viral diarrhea virus (BVDV) antigen were evaluated in skin. Ear-notch specimens from 2 calves persistently infected with BVDV type 1 were handled in 1 of 3 ways: 1) fixed in formalin promptly and processed for immunohistochemistry (IHC) after 3-176 days; 2) held at 3-4degreesC in plastic bags up to 10 days, then fixed in formalin for 2-5 days before processing; or 3) exposed to room air and temperature for 1-5 days before formalin fixation. Immunohistochemical staining intensity was evaluated without the knowledge of specimen handling. Staining of specimens that had been promptly fixed in formalin was moderate to strong at all fixation periods through 36 days, weak or no staining was evident in specimens fixed for 176 days. Refrigerated specimens typically had moderate to strong immunohistochemical staining. Even after 10 days of refrigeration before fixation, all immunohistochemical reactions were positive. However, no immunohistochemical staining was detected in any specimen that was exposed to room air. Results indicate that prompt formalin fixation is optimal for BVDV IHC. Samples can be held in formalin at least 36 days, without loss of reactivity. A 1-day delay in fixation caused no loss of reactivity, provided the specimen was refrigerated and protected from desiccation.

Animals↗

PubMed2003

Uterine neoplasia in 13 cats.

Thirteen uterine tumors were diagnosed in 13 cats and accounted for 0.29% of all feline neoplasms received during a 9.6-year period. Age at diagnosis ranged from 3 to 16 years; median 9 years. Six were Domestic Shorthair cats, and 7 were purebred cats of 5 different breeds. Eight adenocarcinomas and 1 mixed Müllerian tumor (adenosarcoma) comprised the endometrial tumors. Myometrial tumors included 3 leiomyomas and 1 leiomyosarcoma. One of the adenocarcinomas developed in the uterine stump of an ovariohysterectomized cat; the other cats were sexually intact. Concurrent mammary adenocarcinoma was diagnosed in 1 cat with uterine adenocarcinoma and in another with uterine leiomyoma. Tumors were discovered during elective ovariohysterectomy in 2 cats, but at least 3 others had experienced reproductive problems (infertility or pyometra). Five cats presented for abdominal or pelvic masses. Endometrial adenocarcinomas were positive immunohistochemically for cytokeratins and negative for smooth muscle actin (SMA): 1 of 6 cats was positive for vimentin and 4 of 8 were positive for estrogen receptor-alpha (ER alpha). Adenosarcoma stromal cells were positive for vimentin and ER alpha but negative for cytokeratins and SMA. Smooth muscle tumors were positive for vimentin and SMA and negative for cytokeratins. Leiomyomas, but not the leiomyosarcomas, were positive for ER alpha. Adenocarcinomas in 4 cats had metastasized by the time of ovariohysterectomy. Two other cats were euthanized 5 months after ovariohysterectomy; at least one of these cats had developed an abdominal mass that was not examined histologically. Only 2 cats with endometrial adenocarcinoma had disease-free intervals longer than 5 months after surgery. Metastasis was not detected in any mesenchymal tumor; however, these cats were either euthanized on discovery of the tumor or the tumor was first detected at necropsy.

Adenocarcinoma↗

PubMed2002

Islet hyperplasia in callitrichids.

Five callitrichids (three common marmosets -Callithrix jacchus -, a black tufted-eared marmoset -C. penicillata-, and a saddle-back tamarin -Saguinus fuscicollis) were diagnosed with islet hyperplasia by histopathology and immunohistochemistry. All were privately-owned, unrelated callitrichids ranging from 2- to 4-year-old. Relevant findings were anorexia (3/5), vomiting (2/5), ptyalism (1/5), polyuria/polydipsia (1/5), respiratory distress (1/5), hyperglycemia (2/3) and glycosuria (1/1); hyperglycemia and glycosuria were associated with pregnancy in a common marmoset and resolved after reducing simple carbohydrates in diet. All five animals died, three of them after few premonitory signs; in two cases, other concurrent diseases unrelated to islet hyperplasia were considered the cause of death. Additional animals from two facilities had high weight (4), physical obesity (3), polyuria/polydipsia/polyphagia/uriposia (1), hyperglycemia (1), and/or glycosuria (2). Pathologic findings in the deceased callitrichids were: islet hyperplasia (5/5); hemosiderosis (5/5); lipomatosis (4/5) of several tissues (atria, 3/5; pancreas, gall bladder, intestine, esophagus, and thyroid, 2/5; liver, 1/5); pancreatic necrosis or steatonecrosis, and/or acute pancreatitis (3/5); and vacuolation of hepatocytes and renal tubular cells most likely consistent with hepatorenal lipidosis (2/5). The islets of Langerhans were more numerous and larger than in a control, and morphologically normal in all cases, except in a common marmoset that had a few cells with a foamy cytoplasm and shrunken hyperchromatic or picknotic nucleus. Insulin (5/5), glucagon (3/5), and somatostatin (3/5) immunohistochemistry revealed that most cells stained positively for insulin diffusely in their cytoplasm (5/5) (staining restricted to the vascular pole of b-cells in the control). These findings suggest that obesity, insulin resistance and/or type II diabetes may be implicated and thus a prospective study on these diseases in callitrichids is necessary to determine their etiopathogenesis.

Animals↗

PubMed2002

Metastatic pulmonary adenocarcinoma in a llama (Lama glama).

An adult female llama with a comminuted fracture of the left femoral head was necropsied. A firm multinodular mass infiltrated skeletal muscle adjacent to the fracture. Multiple, firm, white nodules were in the pulmonary parenchyma and pleura. A single nodule was in the liver. Microscopically, transition from nonneoplastic bronchiolar epithelium to neoplastic epithelium that formed acinar structures was evident at bronchioloalveolar junctions. A diagnosis of pulmonary adenocarcinoma was made. Similar neoplastic tissue was in the liver and in the perifemoral mass. Immunohistochemically, neoplastic cells were positive for pan-cytokeratin, cytokeratin 7, and cytokeratin 5/6 antibodies and negative for vimentin and cytokeratins 8/18 and 20.

Adenocarcinoma↗

PubMedDate not supplied

Glomerulocystic kidney disease in a Belgian Malinois dog: an ultrastructural, immunohistochemical, and lectin-binding study.

Renal cysts in the cortex of a juvenile Belgian Malinois dog with acute renal failure were studied by means of light, scanning and transmission electron microscopy, immunohistochemistry for intermediate filaments, and binding for wheat germ agglutinin (WGA), peanut agglutinin (PNA), and Maclura pomifera agglutinin (MPA) lectins to determine the morphological and histochemical features of the epithelial cells of these cysts. The cysts were renal corpuscles with expanded urinary space. Glomerular tufts were small with poorly developed capillary loops and increased mesangial matrix. Continuity with the proximal tubule was evident in some cystic glomeruli. Two cell types lined Bowman's capsule. One was squamous with a central cilium and microvilli. The other had morphological and histochemical features of immature podocytes (parietal podocytes). These cells were round and protruded into the urinary space; they had thick cytoplasmic projections that resembled foot processes of podocytes, microvilli, and filtration slits. The parietal podocytes expressed vimentin and cytokeratins and had affinity for WGA as do normal immature podocytes. These features suggest that the parietal podocytes are derived by metaplasia of the parietal cells. The basement membrane of Bowman's capsule was irregularly thickened and showed multifocal glycosylation changes with lectin histochemistry (WGA, PNA, MPA) in areas adjacent to the parietal podocytes. Histologic and ultrastructural findings in this dog are consistent with glomerulocystic kidney disease. This is the second report of canine glomerulocystic kidney disease. Features are similar to those of the human counterpart, but it is unclear whether genetic defects cause the disease in the dog. The presence of parietal podocytes in all cysts suggests that abnormal differentiation may play an important role in the pathogenesis of this type of polycystic kidney disease.

Animals↗