Six dogs with spontaneous heartworm disease were injected with a single dose of ivermectin. After 48 h of treatment, microfilariae counts were reduced by 92%-98% of pretreatment counts. In pretreatment biopsies examined by light and electron microscopy, microfilariae were unaltered in the sinusoids of the liver and also in the glomerular capillaries and interstitial blood vessels of the kidney. However, there was irregular thickening and dense deposits in the basement membranes of glomerular capillaries, along with a modest increase in mesangial cells and matrix. In post-treatment liver biopsies examined by light microscopy, there were numerous granulomas in the sinusoids which contained degenerated microfilariae. In post-treatment kidney biopsies there was moderate thickening of glomerular basement membranes along with pronounced proliferation of mesangial cells and matrix. Glomerular capillaries were partially or completely occluded by degenerated microfilariae. In addition, there were interstitial granulomas in the kidney. It was observed with the aid of electron microscopy that highly vacuolated and degenerated microfilariae were incorporated into granulomas in the liver sinusoids of post-treatment biopsies. In post-treatment kidney biopsies glomerular capillaries were usually occluded by degenerated microfilariae. Basement membranes were thickened and contained dense deposits. Mesangial cells and matrix were extensively increased. Interstitial granulomas in the kidney contained dead microfilariae.

Animals↗

PubMed1985

Fractured jaw.

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Aged↗

PubMed1984

An investigation of the role of immunologic factors in anemia associated with canine heartworm disease.

Direct Coombs' antiglobulin tests were performed on 80 dogs with patent Dirofilaria immitis infection and 170 dogs negative for microfilaria of D. immitis. Presence or absence of anemia was determined by hematocrit in 55 of the heartworm negative dogs and 68 of the dogs with heartworm disease. Heartworm infected dogs showed a higher incidence (37%) of anemia than noninfected dogs (14.5%). Anemia was most prevalent in two groups of dogs with heartworm infection, one group showing vena caval syndrome (91%) and the other occult dirofilariasis (62.5%). These latter two groups of dogs also showed a significantly higher number of positive Coombs' reactions at 37 degrees C than other dogs with heartworm disease and the noninfected dogs. The number of positive Coombs' reactions at 4 degrees C among the total of 80 dogs with heartworm infection was significantly higher than that for dogs without heartworm disease. However, there was no positive correlation between anemia and the outcome of the Coombs' test at either temperature. These findings do not suggest that immunologic factors play a major role in the pathogenesis of anemia in dogs with heartworm disease.

Anemia, Hemolytic↗

PubMed1983

Case 45, part I.

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Aged↗

PubMed1983

Clinicopathologic conferences. Case 45, Part II: Dentigerous cyst of the mandible with ameloblastomatous changes.

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Aged↗

PubMed1982

Fate of microfilariae of Dirofilaria immitis following use of levamisole as a microfilaricide.

A pretreatment liver biopsy was secured from each of three dogs with Dirofilaria immitis microfilariae counts of 29,500, 24,700, and 76,700/ml blood, respectively. Post-treatment biopsies were obtained 30 h later following treatment with a single dose of levamisole and a reduction in microfilariae counts of up to 80%. Both pre- and posttreatment biopsies were examined by light and electron microscopy. Microfilariae in dilated sinusoids of pretreatment liver biopsies were not degenerated and were unattended by an inflammatory reaction when examined by either method. However, degenerated microfilariae were present within granulomas in post-treatment liver biopsies examined by light and electron microscopy. Several stages of degeneration of microfilariae, including phagocytosis, were identified by the latter method.

Animals↗

PubMed1980