Luiz Francisco Irigoyen

Estudo retrospectivo de 761 tumores cutâneos em cães

The biopsy files in dogs from the Veterinary Pathology Laboratory of the Universidade Federal de Santa Maria, RS, Brazil, from 1964 to 2003, were reviewed for skin tumors. In the 703 files, 570 (81.0%) it was reported that the dog had only one skin tumor and in 133 (19.0%), more than one tumor was described in the skin. Six hundred and fifty four (93.1%) dogs had only one histologic type of tumor and 41 (5.8%) had two tumors of different histologic types. In seven (1.0%) dogs there were three tumors of different histologic types and in one (0.1%) four histologically unrelated tumors were diagnosed, performing 761 tumors. Out of the total of 761 skin tumors found, 673 (88.4%) were neoplastic and 88 (11.6%) were non-neoplastic. The 15 more frequently found tumors, in decreasing order of frequency, were: mast cell tumor, squamous cell carcinoma, perianal adenoma, lipoma, trichoblastoma, perianal carcinoma, papilloma, follicular cysts, hemangioma, hemangiosarcoma, melanoma, sebaceous adenoma, histiocytoma, nodular sebaceous hyperplasia and fibroma.

Doenças de bovinos no Sul do Brasil: 6.706 casos

The diseases affecting cattle in southern Brazil were studied through a review of the necropsy reports filed at the Laboratorio de Patologia Veterinaria of the Universidade Federal de Santa Maria (LPV-UFSM), Rio Grande do Sul, and pertaining to the examination of 6.076 cattle during 1964-2008. Of those exams 29.9% were necropsies performed at the LPV-UFSM and 79.1% were mailed-in organ fragments from necropsies performed at the field by veterinary practitioners. Autolysis and non-representative sampling o mailed in organs were the main reasons for non-conclusive diagnosis. Poisoning by Senecio spp. was the main cause of death in cattle in this study and poisonous plants together with toxi-infections accounted for 22.8% of the cases with conclusive diagnosis. Inflammatory diseases together with parasitic diseases accounted for more than 30% of cattle diseases and babesiosis and anaplasmosis were the main diseases in this category. Other categories were distributed in the following order: neoplasms and tumor-like lesions (13.87%), diseases caused by physical agents (2.7%), metabolic and nutritional diseases (2.46%), circulatory disturbances (1.4%), degenerative diseases (1.1%), developmental disorders (0.54%), iatrogenic diseases and sundry lesions. The high prevalence of tumors in cattle in this study was attributed to the chronic ingestion of Pteridium aquilinum, a common toxicosis in the region. The main diseases in cattle from the studied region are related to environmental factors associated to the predominantly husbandry practices adopted in the region.

Aspectos epidemiológicos, clínicos e distribuição das lesões histológicas no encéfalo de bovinos com raiva

The type, distribution and intensity of the histopathological changes were determined in the brain of 25 cattle which had neurological signs and were confirmed as rabies cases by direct immunofluorescent antibody or biological assay in mice. Sections of the brain examined included medulla at the obex; pons and cerebellar peduncles/ cerebellum; mesencephalon at the level of rostral colliculi; diencephalon and telencephalon through the mamillary bodies; and telencephalon at the level of frontal cortex. The cervical spinal cord was also examined in seven of those cases. The duration of clinical course averaged five days and was characterized by ascendent paresia. Specific necropsy findings were absent. Microscopically brainstem, cerebellum and cervical spinal cord were more affected than the thalamus and telencephalon, including hippocampus. The type of lesions were characteristic of viral infection and included non-suppurative encephalomyelitis with neuronal degeneration, nodular gliosis, and mononuclear perivascular infiltrate. Negri bodies were observed in 17 (68%) of the examined brains. The observed intensity and distribution of the lesions were correlated with the signs and duration of the clinical disease.

Intoxicação espontânea por fedegoso em bovinos: relato de 16 surtos

Sixteen outbreaks of Senna occidentalis (coffee senna) that occurred in cattle in the state of Rio Grande do Sul, Brazil, were reviewed. The great majority (75%) of the outbreaks occurred in adult cattle at pasture during the autumn and winter months with 50% in May, evidencing a striking seasonality. Mortality rates varied from 4.2% to 55.2% and cattle died 2 days up to 2 weeks after showing clinical signs that included dry feces (occasionally diarrhea), muscle weakness, reluctance to move, tachypnea, instability of the hind limbs with dragging of the toes, tremors in muscles of the thighs, neck, and head, ear dropping, sternal recumbency, lateral recumbency and death. Myoglobinuria characterized by a dark red or black discolored urine was a consistent finding in cattle affected at pasture but not in those poisoned by ration contaminated with coffee senna beans. Creatine phosphokinase serum activity was marked ly elevated. Main gross changes observed in 23 necropsies involved skeletal muscles of the hind limbs. These changes consisted of varying degrees of paleness of muscle groups. Subepicardial and subendocardial hemorrhages were present in the hearts of all affected cattle. Histologically a segmental degenerative myopathy of striated muscles was present in every case and had a multifocal polyphasic or monophasic character. Myocardial (3/23), hepatic (3/13), renal (3/10), and splenic (1/6) microscopic lesions were observed occasionally. Myocardial lesions were mild and consisted of vacuolation of cardiomyocytes or focal fibrosis. Hepatic changes consisted of diffuse hepatocelular vacuolation, cytosegrosomes within hepatocytes, and individual hepatocellular necrosis. Kidneys had vacuolar degeneration of tubular epithelium associated with acidophilic casts (proteinosis) within tubular lumina. In the spleen there was marked necrosis of lymphocytes of the white pulp. No histological changes were found in the brains of 13 affected cattle. The data of this study suggest that coffee senna poisoning is an important cause of death in cattle in southern Brazil.

Aspectos patológicos de 155 casos fatais de cães atropelados por veículos automotivos

Motor vehicle-related trauma significantly contributes to death statistics of dogs. There are however few documented reports on the pathological aspects of such cases. This paper describes 155 fatal cases of dogs victimized by motor vehicle accidents. In 138 (89.0%) of the 155 dogs hit by motor vehicles there were lesions that could explain the death or reason for these dogs being euthanatized. These lesions included vertebrospinal trauma (43 [27.7%]), rupture of parenchymal organs (40 [25.8%]), cranioencephalic trauma (28 [18.1%]), rupture of hollow organs (16 [10.3%]), rib fracture with subsequent laceration of parenchymal organs (15 [9.7%]), and diaphragmatic rupture with displacement of abdominal viscera into the thoracic cavity (10 [6.4%]).

Intoxicação experimental por Phalaris angusta (Gramineae) em bovinos

To investigate the effects of the ingestion of different amounts of Phalaris angusta, eight 6-8-month-old calves were assigned to four treatment groups. Group I calves were fed only P. angusta. Group II calves were fed a mixture of 75 % of P. angusta and 25% of oat (Avena sativa) and ryegrass (Lolium multiflorum), whereas group III calves received a mixture of 50% of P.angusta and 50% of oat and ryegrass. Group IV calves received only oat and ryegrass and served as controls. P. angusta was toxic for calves. One group I calf died 34 days after the beginning of the ingestion of the plant, and the other calves were euthanatized in extremis 18 to 32 days after de beginning of the experiment. The main clinical signs were locomotor disorders, generalized tremors, frequent falls, and convulsions. Gross findings were confined to the brain and consisted of focal areas of green-bluish discoloration in the thalamus, mesencephalon, and medulla oblongata. Microscopic lesions were characterized by the presence of a intracytoplasmic yellow-brown indole-like pigment in neurons from grossly affected areas. Ultrastructural changes consisted of swollen lysosomes containing membranous material with variable orientation and density. The amount of ingested P. angusta was not a determinant factor for the severity of clinical signs and lesions. The extension of gross and microscopic lesions was not directly related with the intensity of the clinical signs. P. angusta was exclusively neurotoxic and should be considered as a differential diagnosis in cases of neurological disease of cattle with clinical signs consistent with tremorgenic syndrome.

Ultrastructural observation of the airways of recovered and susceptible pigs after inoculation with Mycoplasma hyopneumoniae

To determine the morphological differences in the epithelium of the airways of recovered and susceptible pigs after Mycoplasma hyopneumoniae challenge, twenty-four 4-week-old M. hyopneumoniae-free pigs were intratracheally inoculated with 107ccu/ml of a pure low-passaged culture of the P5722-3 strain of M. hyopneumoniae challenge material. Eight pigs (group I) were challenged at the beginning of the experiment and rechallenged 3 months later. Group II pigs were also challenged at the beginning of the experiment and necropsied 3 months later. Group III pigs were challenged at the same time as the rechallenge of group I pigs. Eight nonchallenged pigs served as controls (group IV). Three days after the second challenge of group I and the first challenge of group III, and every 3 and 4 days thereafter, two pigs from each group were euthanatized by electrocution and necropsied. Samples of bronchi and lung tissue were examined using light and electron microscopy (SEM and TEM). Macroscopic lesions were observed in the lungs of all group III pigs (average = 4.74%) and were characterized by purple-red areas of discoloration and increased firmness affecting the cranioventral aspect of the lungs. Macroscopic lesions of pneumonia in groups I and II were minimal (less than 1%). There were no gross lesions of pneumonia in control (group IV) pigs. Microscopic lesions were characterized by hyperplasia of the peribronchial lymphoid tissue and mild neutrophilic infiltrates in alveoli. Electron microscopy showed patchy areas with loss of cilia and presence of leukocytes and mycoplasmas in bronchi of susceptible pigs (group III). The bronchial epithelium of rechallenged (group I), recovered (group II), and control (group IV) pigs was ultrastructurally similar indicating recovery of the former two groups. Although mycoplasmas were seen among cilia, a second challenge on pigs of group I did not produce another episode of the disease nor did it enhance morphological changes, suggesting that those pigs could become carriers of M. hyopneumoniae.

Dermatite alérgica sazonal em ovinos

An outbreak of acute seasonal allergic dermatitis is described in sheep from the municipalities of Sao Vicente do Sul and Jaguari, Rio Grande do Sul, Brazil. Affected sheep were crossbreeds of different categories. Skin lesions were observed mainly in the head (ears and around the eyes, muzzle, and lips), mammary gland, distal portions of the limbs and ventral abdomen. Two lesion patterns were found; an acute pattern showed marked erythema associated with numerous papules, pustules, epidermal colarettes, and crust; in a chronic pattern the same anatomical sites had lichenified, ulcerated, exudative, crusted, and alopecic areas, which were occasionally hemorrhagic. Microscopically, sheep that were recently affected had perivascular eosinophilic dermatitis; in the skin of more chronically affected sheep there was superficial lymphocytic and histioplasmocytic perivascular dermatitis.

Lesões do sistema urinário em 1.063 cães

The aim of this study was to determine the prevalence, epidemiology, clinical significance, and possible associated causes of the urinary system lesions in dogs necropsied between January 1999 and December 2010 at the Laboratorio de Patologia Veterinaria of the Universidade Federal de Santa Maria (LPV-UFSM). To accomplish this, the necropsy reports were analyzed retrospectively. In this time frame, 3,189 dogs were necropsied and about 30% had lesions in the urinary system. In most of the dogs (79.1%), lesions were single and in about 21% they were multiple, totalizing 1,373 lesions. Out of them, 1,014 (73.8%) were observed in the kidney and 359 (26.2%) were in the lower urinary tract (LUT). One third of the lesions in the urinary system were causes of spontaneous death or reason for euthanasia (SD/EUTH) of the affected dogs. The other two third of the lesions were considered incidental findings. The main renal lesions diagnosed, in descending order of prevalence, were: tubulointerstitial nephritis, infarct, granulomatous nephritis (parasitary), glomerulonephritis, metastatic/multicentric neoplasms, pyelonephritis/pyelitis, and hydronephrosis. The main LUT lesions, in descending order of prevalence, were: cystitis, presence of viral inclusions bodies (morbillivirus), urolithiasis, urinary bladder dilatation, urinary bladder rupture (with uroperitoneum), and metastatic/multicentric neoplasms. Epidemiological aspects such as gender, breed, and age of affected dogs had expressive variations according to the type of lesion diagnosed. Uremia was observed in a significant number of cases of SD/EUTH and was mostly due to renal lesions.

Arterial diffuse intimal thickening associated with enzootic calcinosis of sheep

Morphometric, immunohistochemical and ultrastructural studies were carried out on the diffuse intimal thickening (DIT) in arteries of 7 sheep with clinical signs of naturally occurring enzootic calcinosis due to ingestion of the plant Nierembergia veitchii. Arterial lesions consisted of medial deposition of calcium salts and DIT. Calcification of the intima was rare, mild and located near the elastic lamina. By immunohistochemistry a-actin was detected in cells of the media and in cells forming the intimal thickening. Receptors for 1,25(OH)2 vitamin D3 were detected in nuclei of intimal, medial and endothelial cells. DIT was irregularly distributed and was neither proportionally related to the intensity of the underlying mineralization area nor to the thickening of the remaining media. Ultrastructural morphometry in smooth muscle cells (SMCs) of the media and thickened intima revealed, in the latter, an increase of 318% in the volumetric fraction of those organelles involved in synthesis and a proportional decrease in contractile elements when compared to normal values of media cells. There were histological and ultrastructural evidences of modification of SMCs and their migration to the intima, where they proliferated causing DIT. It was concluded that DIT is a consistent component of arteriosclerotic lesions in N. veitchii induced calcinosis of sheep and that the predominant cell in this process is the SMCs originated from its predecessors of the media. It is suggested that the inducing factor for the arterial changes is 1,25(OH)2 D3 present in N. veitchii.