Vertical position of the patella in the stifle joint of clinically normal large-breed dogs

OBJECTIVE: To define the vertical position of the patella in clinically normal large-breed dogs. SAMPLE POPULATION: Cadavers of 13 clinically normal large-breed dog. PROCEDURE: Both hind limbs were harvested with intact stifle joints and mounted on a positioning device that allowed full range of motion of the stifle joint. Lateral radiographic views were obtained with the stifle joints positioned at each of 5 angles (148 degrees, 130 degrees, 113 degrees, 96 degrees, and 75 degrees). Vertical position of the patella through a range of motion was depicted on a graph of mean stifle angle versus corresponding mean proximal patellar position (PPP) and distal patellar position (DPP) relative to the femoral trochlea for each dog. Ratio of length of the patellar ligament to length of the patella (L:P) was determined for each dog. Overall mean, SD, and 95% confidence intervals for L:P were calculated for all dogs. RESULTS: Evaluation of vertical position of the patella through a range of motion revealed a nearly linear relationship between joint angle and PPP and joint angle and DPPF Evaluation of L:P results did not reveal significant differences between limbs (left or right) or among joint angles. Overall mean +/- SD L:P for all dogs was 1.68 +/- 0.18 (95% confidence interval, 1.33 to 2.03). CONCLUSIONS AND CLINICAL RELEVANCE: The L:P proved to be a repeatable measurement of vertical patellar position, which is independent of stifle angles from 75 degrees to 148 degrees.This measurement could be used as a quantitative method for diagnosing patella alta and patella baja in large-breed dogs.     

Experimental lead-poisoning in dogs

Extract

It has long been established that antibodies to the major anaerobic infections in sheep are transferred to the suckled lamb in the colostrum or first milk. Effective absorption of such antibodies from the gastro-intestinal tract takes place during the first fifteen hours of life; hence, in order to acquire protection the lamb must have suckled during this period. The degree of protection available in the colostrum will depend on the success of the immunization procedures in the ewe.     

Experimental encephalitozoonosis in neonatal dogs

The in vivo infection of neonatal dogs by the microsporidian protozoan parasite, Encephalitozoon cuniculi, was studied. Microscopic examination of tissues from infected animals showed granulomatous nephritis, meningoencephalitis, hepatitis, and pneumonitis. A large component of the inflammatory infiltrate consisted of plasma cells and lymphocytes. In addition, hyperplasia of B-lymphocyte-dependent regions of lymph nodes and erythrophagocytosis were consistently seen in infected dogs. Infected dogs developed lymphocytosis, hypergammaglobulinemia, anti-encephalitozoon antibodies, and an antigen-specific blastogenic response to E. cuniculi spores. Lymphocyte blastogenic responses to the lectin phytohemagglutinin A (PHA) were depressed compared to controls. Dogs dying during the 2-month experimental trial were bacteremic. The findings of these experiments suggest that postnatal infection results in a demonstrable although seemingly ineffective immune and inflammatory response without detectable clinical disease.     

犬同种异体半月板的移植

为了探索犬半月板损伤的有效治疗方法,本研究建立了犬半月板缺损模型,并采用同种异体半月板全移植和半移植2种方式修复半月板缺损。术后第5周末,所有移植犬站立、行走和上台阶均趋于正常,但不移植的半月板缺损对照犬行走时仍有轻度跛行,上台阶困难。术后第6周膝关节功能Lysholm评分,全移植组和半移植组与正常对照组差异不显著,不移植组与对照组差异显著。肉眼检查见供体半月板在受体内生长良好。半移植组供体半月板的色泽和弹性更接近正常半月板。组织学观察,供体半月板和受体关节囊、供体半月板和保留的受体半月板接合良好,接合处组织生长旺盛。胫骨平台软骨Mankins评分,全移植组和半移植组与对照组差异不显著,不移植组与对照组差异显著。本研究结果表明同种异体半月板移植可有效保护胫骨平台软骨、改善膝关节功能,完全可以用于犬半月板损伤的治疗。     

Experimental onion-induced hemolytic anemia in dogs

Within one day following a single oral dose of dehydrated onions, dogs were found to have large numbers of Heinz bodies within erythrocytes. The percentage of erythrocytes that contained Heinz bodies increased slightly to a maximum on day 3 and then declined. The turbidity index increased more gradually with a maximal value on day 4. Erythrocytes with hemoglobin contracted to one side of the cell (eccentrocytes) also appeared after onion feeding. Eccentrocytes are believed to result from a direct injury to the erythrocyte membrane. As with Heinz body-containing cells, the percentages of eccentrocytes present declined as anemia developed. The packed cell volume began to decrease one day after onion administration. A mean decrease of 19 percentage points was reached by day 5. The most anemic dogs had evidence of intravascular hemolysis. Reticulocytosis was first observed five days after onion administration. A slight increase in methemoglobin content was measured four hours after onion administration. No significant changes in erythrocyte reduced glutathione concentration were measured. Transient neutrophilia occurred concomitant with the peak reticulocyte response.     

Experimental parvovirus infection in dogs.

Five eight week old dogs were inoculated orally and intranasally with cell culture origin canine parvovirus. Three dogs became depressed and anorectic and developed a mild (one dog) to severe diarrhea five days postinfection. The remaining dogs had subclinical infections but developed a lymphopenia followed by a transient lymphocytosis. The ill dogs developed mild (one dog) to severe neutropenia and a moderate lymphopenia. One died nine days postinfection. Recovery was associated with cessation of viral excretion and with lymphocytosis and antibody production. Two of three dogs challenged intragastrically developed mild clinical signs and a moderate panleukopenia four to eight days postinfection. The pathological changes of the experimental disease were very similar to that of spontaneous disease. Bone marrow changes included a severe granulocytic and mild erythroid depletion. The pathogenesis of canine parvovirus infection is discussed.     

Experimental acute toxicity of xylitol in dogs

The Cases of xylitol poisoning in dogs are increasing as a result of ingestion of xylitol-containing products. Eighteen adult, clinically normal Pekingese dogs were orally dosed with 1 or 4 g/kg xylitol in aqueous solution. Blood samples were collected before and after dosing. Plasma insulin concentrations of both treated groups rose sharply from 20 min after xylitol dosing, peaking at 40 min. Hypoglycemia followed the increase in insulin concentration, with blood glucose values started to decrease 30 min after dosing. Other plasma biochemistry changes associated with xylitol administration were increased alanine aminotransferase and aspartate aminotransferase activities, hypophosphatemia, hypokalemia, and hypercalcemia. Plasma sodium and chloride concentrations remained normal. This study established a biochemical basis for diagnosis and treatment of xylitol poisoning in dogs.     

Lesions in dogs following renal transplantation and immunosuppression

Renal allografts were transplanted into 20 dogs (12 beagles, eight mongrels) following a prescribed protocol for pre-transplantation blood transfusions and kidney exchange. Immunosuppressive therapy (azathioprine and prednisone) was modified as needed for each dog. Seven of the beagle dogs survived for 1 year and were then euthanized; all other dogs died or were euthanized prior to 1 year post-transplantation. Graft rejection and renal failure were the greatest causes of mortality. Renal lesions which contributed to the death of some animals included renal vein thrombosis, nephrosis, and pyelonephritis. Inflammation of the lower respiratory tract (bronchitis, pneumonia, and pleuritis) was a contributory cause of death in some dogs. Cystitis and ureteritis occurred in almost half of the dogs. Prostatitis was seen in six of the 16 male dogs. Adrenal cortical atrophy, parathyroid gland hyperplasia, and bone marrow hypocellularity were seen in a majority of the dogs which survived 1 year.     

Experimental infection of Japanese encephalitis virus in dogs

A previous serosurvey of Japanese encephalitis virus (JEV) among dogs suggested that dogs are well suited for use as sentinels for assessing the risk of JEV transmission to humans. To examine the clinical symptoms and duration of anti-JEV antibodies in dogs, three dogs were experimentally challenged with JEV. All JEV-infected dogs did not show any clinical signs or abnormal blood tests, except for C-reactive protein. Virus-neutralization titers rapidly increased and were maintained until 70 days postinfection, and neither the virus nor the viral genome was detected in blood. Thus, since dogs live in close proximity to humans as companion animals, they are well suited for use as sentinels for surveying the human risk of JEV infection.     

Experimental transmission of granulocytic ehrlichial organisms in dogs

Canine granulocytic ehrlichial organisms were transmitted from an infected dog from Missouri to two male, 10-month-old dogs by an intravenous injection of whole blood. Physical or behavioral abnormalities were not detected during the 98 days of evaluation other than a mild pyrexia from Day 18 to 20. Ehrlichial morulae were found in blood granulocytes of Dog 1 from Day 13 to 44 and of Dog 2 from Day 14 to 34 with the peak rickettsemia occurring on Day 16 for both dogs. By Day 21 after inoculaiuon, both dogs had positive titers to Ehrlichia canis. The highest titers for both dogs were found 63 days after inoculation, after which the titers decreased. Most of the hematologic abnormalities (i.e., neutropenia, lymphocytosis, thrombocytopenia) and fever occurred between 18 and 24 days after inoculation. The pathologic bases of these abnormalities were not investigated but their concurrent presence suggested an association with the dogs' immunologic responses to the granulocytic ehrlichial agent. Results from the study indicated that the canine granulocytic ehrlichial agent of Missouri may produce subclinical infections and suggested that dogs may be able to clear the organism without antimicrobial therapy.     

Experimental infection of equine herpesvirus 9 in dogs

Equine herpesvirus 9 (EHV-9), a new neurotropic equine herpesvirus, was inoculated intranasally at 107 plaque-forming units in five dogs to assess its pathogenicity. Dogs showed weight loss, pyrexia, anorexia, and neurologic signs on the fourth day. The EHV-9 virus was recovered from the examined brains. Histologically, dogs had a fulminant nonsuppurative encephalitis characterized by severe neuronal degeneration and loss, with intranuclear inclusions, slight glial reactions, perivascular cuffing, and multifocal hemorrhage. The olfactory bulb and the frontal and temporal lobes were predominantly affected. Immunohistochemistry revealed reactivity for EHV-9 antigen in neurons. All dogs had mild bronchopneumonia and various degrees of lymphoid necrosis. These findings indicate that dogs are fully susceptible to EHV-9 and that EHV-9 can cause fulminant encephalitis with high mortality in dogs, as in gazelles and goats.     

Osteosarcoma of the patella in a dog

Osteosarcoma of the patella was diagnosed by biopsy in a 9-year-old, male dog of mixed breeding. The dog was originally examined because of intermittent lameness of the left hindlimb; there were minimal palpable abnormalities of the stifle. After the diagnosis, the owner refused further treatment for the dog. The dog was reexamined 13 months later because of a marked swelling of the stifle. The dog was euthanatized and necropsy findings confirmed the diagnosis.