Demographics of canine immune-mediated haemolytic anaemia in the Southeastern United States

Detailed examination of the records of 57 dogs referred to our clinic with the diagnosis of immunemediated haemolytic anaemia was accomplished. Only untreated dogs or dogs who had only received supportive therapy were included in the study group comprising 30 male dogs and 27 female dogs. Age distribution followed the general age distribution of our patient population. There was no within-breed sex or age predilection. The youngest dog was 11 months of age and the oldest dog was 13 years of age. Overall mortality rate among the study population was 51% (29 dogs). Certain canine breeds were over-represented in this study and these same breeds had high mortality rates. Included were 11 cocker spaniels (19%; 82% mortality rate, 9 of 11 dogs), nine dogs with terrier in their name (16%; 78% mortality rate, 7 of 9 dogs), six German shepherds (11%; 50% mortality rate, 3 of 6 dogs), five doberman pinschers (9%; 60% mortality rate, 3 of 5 dogs), and five miniature schnauzers (9%; 60% mortality rate, 3 of 5 dogs). Immune-mediated haemolytic anaemia was considered secondary to hepatic disease in 16 dogs (28%), septicaemia in 10 dogs (18%) and neoplasia in six dogs (11%), i.e. signs and data supporting these processes were reported to have preceded anaemia. A total of 29 dogs (51%) also had thrombocytopenia (platelet counts less than 60000 cells/µl), eight (14%) dogs had major venous thrombosis, eight (14%) dogs had associated disseminated intravascular coagulation, and 24 (42%) of the dogs had evidence of renal disease — proteinuria and cylinduria. About 35% (20 dogs) of the patients were treated from June to August, and 63% (36 dogs) of the patients were direct antiglobulin positive (immunoglobulin G with or without complement). A variety of red cell morphological changes were observed including stomatocytes, bowl forms, knizocytes, schistocytes and spherocytes. Spherocytes were observed in 11 dogs (19%). Absolute reticulocytosis was observed in 26 dogs (46%). A variety of treatment combinations including glucocorticoids, azathioprine, cyclophosphamide, anabolic steroids, heparin, intravenous human gamma globulin, and blood component therapy were used without identifiable success associated with any given protocol.     

Dysmyelination of the central nervous system in the Chow-Chow dog

Summary Five Chow-Chow dogs from three different litters had generalized body tremors since birth. Histologically a severe myelin deficiency was found in the central nervous system. The peripheral nerves were normally myelinated. Electron microscopically abnormally thin myelin sheaths and completely naked nerve fibers were found. There were many astrocytes in the myelin deficient areas as well as cells with the characteristic features of oligodendrocytes but also containing fibrils. The present cases are compared to other dysmyelinating diseases and possible pathogenetic mechanisms are discussed.Publication No 1300 School of Vet. Medicine Auburn University     

Repair of sublethal radiation damage by capillaries.

Neovascularization was induced surgically in normally avascular canine corneas to study the repair of sublethal damage in slowly proliferating capillary endothelial cells. Neovascularization was stimulated for 7 days after split dose treatments with ⁶Co γ-rays. Corneal tissue samples were evaluated by quantitative morphometric methods. A time recovery curve was drawn by plotting per cent capillary volume vs time between two equal doses. A typical “Elkind type” of time recovery response was observed. A split dose response assay resulted in an incremental dose D₂—D₁ of 265 rad at the 1% capillary volume level. The results suggest a substantial repair capacity for capillary endothelial cells.     

Immunoglobulins in demyelinating lesions in canine distemper encephalitis

Summary The brains of 14 dogs with canine distemper encephalitis were examined with immunohistologic techniques to search for immunogobulin in demyelinating lesions. Four types of lesions presumably representing a temporal sequence of lesion development were distinguished. Immunohistologic findings included immunoglobulin bearing lymphoid cells, amorphous Ig containing material, immunoglobulin bound to the tissue and immunoglobulin containing macrophages and astrocytes. The humoral immune response was absent or very minimal in acute lesions and very intense in chronic lesions. It was concluded that early demyelination in canine distemper encephalitis occurs in the absence of a local humoral immune response but that this response may aggravate and accelerate myelin destruction in the later stages of the disease.Supported by the Schweizer Nationalfonds grant no 3.805.79 and the Schweizerische Multiple Sklerose Gesellschaft     

Acral mutilation and nociceptive loss in English Pointer dogs

Summary Acral mutilation and analgesia occurred in three of a litter of nine pups produced by a mating of clinically normal English Pointer dogs. Post-mortem studies on one of the affected pups revealed changes at the level of the primary sensory neuron which included: a reduction in spinal ganglia size, a 22–50% deficiency of ganglionic neurons, and a disproportionately large population of small sensory cell bodies. The only change noted in the spinal cord occurred in the dorsolateral fasciculus where reduced fiber density appeared to correlate well with the observed nociceptive defect. Light- and electron-microscopic examination of spinal roots, ganglia, and peripheral nerves provided evidence of myelinated and unmyelinated fiber degeneration. The neuronal degeneration, however, appeared quantitatively inadequate to account for the deficiency of sensory cell bodies. It was concluded that this mutilating acropathy was a manifestation of a sensory neuropathy in which the neuronal deficiency resulted from insufficient development and slowly progressive, postnatal degeneration.The clinical and pathologic findings in this canine disorder were compared with those reported in hereditary sensory neuropathies of man and other animals.This work was supported by NIH grant NS-14242-01, contact RR-9-2102, and Biomedical Research Support Grant funds     

Predictions of blood flow from thermal clearance during regional hyperthermia

In order to provide a method for estimation of regional blood flow during hyperthermia, a mathematical model has been developed which employs thermal clearance to measure this physiologic parameter. Limbs of mongrel dogs were heated with 2450 megaHertz microwaves to temperatures of 43 degrees C, 45 degrees C, or 47 degrees C and thermal washout was measured at five minute intervals throughout each treatment period. Calculated blood flow indicates that in response to heat challenge, normal tissue compensates by increasing regional blood flow within the treatment volume. This increase in blood flow continues to a maximum value after which the blood flow begins to decrease. Data indicate that the time for maximum increase in blood flow (induction time) decreases as treatment temperature increases. These induction times were 40 minutes, 25 minutes, and 15 minutes for treatment temperatures of 43 degrees, 45 degrees, and 47 degrees C, respectively. The data also show that the calculated value of peak blood flow is directly related to treatment temperature. Calculated peak blood flow values reached 37.8, 59.0, and 183.0 ml/minute/100 grams of tissue during 43 degrees, 45 degrees, and 47 degrees C, hyperthermia, respectively. It is suggested that a therapeutic advantage could be gained by treating tumors for a specific length of time during which the blood flow in adjacent normal tissues continues to increase. This would take maximum advantage of normal tissue's ability to compensate for increased temperature, and would exploit any decreased ability of tumor tissue to perform this same function.     

Patterns of innervation of the anterior maxilla: a cadaver study with relevance to canine fossa puncture of the maxillary sinus

OBJECTIVES/HYPOTHESIS: Complications from canine fossa puncture of the maxillary sinus are caused by damage to the anterior superior alveolar nerve (ASAN) and the middle superior alveolar nerve (MSAN). The aim of this study was to elucidate the pattern of ASAN and MSAN within the anterior maxilla and to secondly determine suitable surgical landmarks to aid in accurately localizing the area of the canine fossa least likely to produce complications when a trocar is passed into the maxillary sinus. METHODS: Anatomic dissection of the anterior face of the maxilla from 20 cadaver heads was performed. The pattern and presence of the ASAN and MSAN was identified on each side and tabulated. Landmarks for the safest entry point for canine fossa puncture were determined, and each side had a puncture placed using these landmarks. Any disruption of nerves was noted. RESULTS: Multiple differing patterns of ASAN were identified. The ASAN emerged from its foramen as a single trunk in 30 (75%) sides and in a double trunk in 10 (25%). In 24 (60%), single or multiple branches from the ASAN trunks were identified. A MSAN was identified in 9 (23%) maxillae. The safest entry point for a canine fossa puncture was where a vertical line drawn through the mid-pupillary line was bisected by a horizontal line drawn through the floor of the pyriform aperture. CONCLUSIONS: There is significant variation in the pattern of ASAN and MSAN within the anterior face of the maxilla. By using the newly described landmarks when performing a canine fossa puncture, there is reduced risk of damage to these nerves and provides a reliable point to enter the maxillary sinus.     

Evaluation of acanthocyte count as a diagnostic test for canine haemangiosarcoma

A retrospective case-control study was conducted based on the records of 80 dogs with visceral haemangiosarcoma (HSA) and 200 dogs with various diseases that had clinical features similar to HSA. All dogs were more than 1 year old, had histologically confirmed disease, and had a complete blood count performed prior to the final diagnosis. A standard protocol was used to count acanthocytes on one blood film from each dog. Acanthocyte count had a maximum diagnostic sensitivity of 53.8% (and specificity of 61.5%) at a cutpoint of 1 acanthocyte/2,000 red blood cells. A diagnostic specificity of 100% (and sensitivity of 7.5%) was achieved at a cutpoint of >71 acanthocytes/2,000 red blood cells. The precision of acanthocyte count, within and between raters, varied from poor (unweighted kappa = 0.26) to good (weighted kappa = 0.71) due to the subjective nature of the identification of acanthocytes. Although dogs with acanthocytes were more likely to have HSA (P=0.02), and dogs with HSA had higher acanthocyte counts than controls (P=0.003), acanthocyte count had limited ability to distinguish between dogs with HSA and unaffected dogs with similar signs, as indicated by the receiver operator characteristic plot, which lay approximately along the diagonal. There was no level of acanthocytosis at which HSA could be ruled out, and although HSA could be ruled in at counts >71 acanthocytes/2,000 red blood cells, only six of the 80 dogs with HSA in the study could be identified by this cutpoint.     

Up-regulation of the hyaluronate receptor CD44 in canine distemper demyelinated plaques

CD44 antigen (CD44), the principle cell surface receptor for hyaluronate, is up-regulated in the human demyelinating disease multiple sclerosis on fibrous astrocytes. As astrocytes are the main target cell of canine distemper virus (CDV), the consequences of a CDV infection on the CD44 expression and distribution in brains with spontaneous demyelinating canine distemper encephalitis (CDE) were of interest. Thirteen acute, 35 subacute, and 11 chronic plaques of nine dogs with immunohistologically confirmed CDE and brains of control dogs were included in the study. For light microscopy, 5-μm-thick serial sections were stained with H & E and incubated with monoclonal antibodies (mAbs) against CD44 and canine distemper virus nucleoprotein and polyclonal antibodies (pAbs) against glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP). For immunoelectron microscopy, 90-nm-thick sections were double stained with anti-GFAP and anti-CD44 mAbs to specify CD44-expressing structures. In controls, CD44 was diffusely distributed in the white matter and single meningeal cells exhibited a marginal expression of the antigen. In acute and more prominently in subacute demyelinating encephalitis, there was a plaque-associated up-regulation of CD44 which paralleled GFAP. In chronic demyelinating lesions, a reduction of CD44 associated with a loss of GFAP-positive astrocytes was noted. Additionally, in chronic plaques, CD44 was expressed on the cell membrane of perivascular mononuclear cells. Immunoelectron microscopically, in controls, CD44 was rarely demonstrated on astrocytic cell processes. In contrast, in brains with CDE CD44 was found on the cell membrane of broadened astrocytic cell processes. In summary, CD44 is up-regulated on astrocytes in the early phase of CDE and seems to represent a marker for the activation of immune cells in the late phase of the infection. Received: 4 March 1999 / Revised: 9 June 1999 / Accepted: 28 June 1999     

生物血管异种移植的初步研究

目的为了寻求一种新的小口径血管代用品,建立异种移植的动物实验模型,以观察异种移植物的安全性、可靠性、通畅性及组织学改变。方法共采用17只杂种雌性犬,实验组10只,植入经环氧化物处理的猪血管移植物;对照组7只,植入人造血管。手术方法为右侧股动静脉瘘。术后通过超声和血管造影方法来观察移植血管的通畅性,并在术后3月将移植物取出,进行病理学检查,观察移植前后移植物的组织学改变。结果术后第一周、二周行Doppler超声检查结果,两组动静脉瘘均通畅,2周内血管通畅率为100%。术后3个月动脉造影检查后,生物血管组(PG)通畅5只,通畅率62.5%,e-PTFE组通畅4只,通畅率66.7%。两组数据统计学处理,差异无显著性(P>0.05)。术后3月对移植物取材,进行光镜及扫描电镜病理学检查,通畅的生物血管吻合口无狭窄,吻合部位有新的内膜覆盖,周围组织无钙化,有新生的内皮细胞覆盖。结论经环氧化物处理的猪的血管移植物(PG)生物血管作为异种移植物,生物相容性好,具有一定的可行性。