Familial glomerulonephropathy in the Bullmastiff.

Glomerular disease was diagnosed by histopathologic examination in 11 related Bullmastiff dogs, and clinical and laboratory data were collected retrospectively. Four female and seven male dogs between the ages of 2.5 and 11 years were affected. Clinical signs, including lethargy and anorexia, were nonspecific and occurred shortly before death or euthanasia. In five affected dogs serial blood samples were obtained, and dramatically elevated blood urea nitrogen and creatinine levels were demonstrated up to 2.75 years before death. Protein-creatinine ratios were elevated in six of six dogs and were above normal 3.5 years before death in one dog. The kidneys appeared grossly normal to slightly smaller than normal at necropsy. Histologic abnormalities of the kidneys were consistent with chronic glomerulonephropathy with sclerosis. Examination of the pedigrees of related affected dogs yielded evidence supporting an autosomal recessive mode of inheritance.

Thrombopathies causing bleeding in a boxer and mixed-breed dog.

Hereditary platelet function disorders are clinically characterized by recurrent surface bleeding and prolonged bleeding time, despite normal platelet count and coagulation tests. The authors describe persistent thrombopathies in two young dogs with increased bleeding tendencies but with normal plasma coagulation times and von Willebrand factor (vWf) concentrations. Buccal mucosal bleeding times were prolonged in both dogs. In aggregation studies, platelets underwent only a shape change or minimal aggregation in response to adenosine diphosphate and collagen. Whole-platelet adenine nucleotide concentrations were normal. Electron microscopic evaluation of fibrinogen and vWf binding to the platelets of case no. 1 demonstrated the presence of glycoprotein IIb/IIIa and Ib receptors. Thus, the intrinsic platelet function defects may be different in these two dogs and may likely represent secretion/signal transduction disorders.

Sry-negative XX sex reversal in a family of Norwegian Elkhounds.

Two related female Norwegian Elkhounds were evaluated at 6 and 8 months of age for enlarged clitori. Both had a 78 XX karyotype. Histology of their internal reproductive tracts demonstrated 1 to be an XX true hermaphrodite with bilateral ovotestes and the other to be an XX male with bilateral aspermatogenic testes. Polymerase chain reaction-based tests of genomic DNA showed that both dogs lacked Sry, the testis-determining gene. Pedigree analysis was consistent with an autosomal recessive mode of inheritance, as has been reported in the American Cocker Spaniel and the German Shorthaired Pointer. This is the 1st reported case of familial Sry-negative XX sex reversal in the Norwegian Elkhound. A summary of 34 previously unreported cases of dogs with masculinized external genitalia and a normal 78 XX karyotype seen from 1980 to 1997 is given.

Sulfamidase deficiency in a family of Dachshunds: a canine model of mucopolysaccharidosis IIIA (Sanfilippo A).

Mucopolysaccharidosis IIIA (MPS IIIA or Sanfilippo A, McKusick 25290) was diagnosed in two adult wire-haired Dachshund littermates. Clinical and pathologic features paralleled the human disorder; both dogs exhibited progressive neurologic disease without apparent somatic involvement. Pelvic limb ataxia was observed when the dogs were 3 y old and progressed gradually within 1-2 y to severe generalized spinocerebellar ataxia. Mentation remained normal throughout the course of the disease. A mucopolysaccharide storage disorder was indicated in both dogs by positive toluidine blue spot tests of urine. The diagnosis of MPS IIIA was confirmed by documentation of urinary excretion and tissue accumulation of heparan sulfate and decreased sulfamidase activity in fibroblasts and hepatic tissue. Mild cerebral cortical atrophy and dilation of the lateral ventricles were grossly evident in both dogs. Light microscopically, fibroblasts, hepatocytes, and renal tubular epithelial cells were vacuolated. Within the nervous system, cerebellar Purkinje cells, neurons of brainstem nuclei, ventral and dorsal horns, and dorsal ganglia were distended with brightly autofluorescent, periodic acid-Schiff-positive, sudanophilic material. Ultrastructurally, visceral storage presented as membrane-bound vacuoles with finely granular, variably electron-lucent contents. Neuronal storage appeared as membranous concentric whorls, lamellated parallel membrane stacks, or electron-dense lipid-like globules. This represents the first reported animal disease homolog of the human Sanfilippo A syndrome.

X-linked ectodermal dysplasia in the dog.

A male German shepherd pup had symmetrical areas of hairlessness as well as missing and misshapen teeth. There was no family history of a similar phenotype. In biopsies of the hairless skin and foot pads there were no hair follicles, adnexal structures, or eccrine glands. These findings resemble those in ectodermal dysplasia in the Tabby mouse and anhidrotic/hypohidrotic ectodermal dysplasia (HED) in man, which are both X-linked recessive disorders and thought to be homologous gene defects. While similar cases of ectodermal dysplasia have been reported in the dog and some genetic studies carried out, definitive confirmation of X-linked inheritance of canine ectodermal dysplasia is lacking. Family studies and experimental matings using the propositus gave results that confirm X-linked recessive inheritance. On statistical grounds, it is concluded that ED in the propositus is due to a new mutation. A colony of dogs with this mutation is maintained for further study.

Transfer of colostral antibodies from queens to their kittens.

OBJECTIVE: To examine systemic immunity in kittens, including transfer of maternal immunoglobulins from the queen to kittens, and subsequent decay of passively obtained immunoglobulins. ANIMALS: 6 healthy queens and their 46 kittens. PROCEDURE: Immunoglobulin concentrations were measured in serum, colostrum, and milk of queens and in their kittens' sera. Decay rate constants and half-lives of maternally derived immunoglobulins were determined. To determine intestinal absorption, foreign IgG was given to kittens at 6- to 8-hour intervals after birth, and bovine IgM was given to kittens at birth. RESULTS: Immunoglobulin concentrations of milk and colostrum did not differ significantly after removal of milk fat. Mean IgG concentration was higher in colostrum/ milk, whereas mean IgA and IgM concentrations were lower than those in the queens' serum. No IgG or IgA was detected in any of the precolostral serum samples obtained from kittens. Small amounts of IgM were present in the sera from 5 kittens at birth. Transferred IgG and IgA decreased rapidly with half-lives of 4.4 +/- 3.57 and 1.93 +/- 1.94 days, respectively. Serum IgM concentration increased irregularly during the first week of life, followed by a steady increase. Foreign IgG given up to 12 hours after birth was detected in kittens' serum, whereas IgG given at or after 16 hours was not found in any kitten's serum. CONCLUSIONS: Milk and colostral immunoglobulin concentrations did not differ significantly. The half-lives of maternally derived IgG and IgA in kittens were shorter than those reported in dogs. IgG given at or after 16 hours of life was not absorbed by neonatal kittens. CLINICAL RELEVANCE: Queen's milk obtained anytime during lactation may be used as a replacement for colostrum as a source of antibodies for neonatal kittens. Kittens at risk for neonatal isoerythrolysis must only be removed from the queens during the first day of life.

Hepatic storage of glycosaminoglycans in feline and canine models of mucopolysaccharidoses I, VI, and VII.

Livers from normal cats and dogs, cats with mucopolysaccharidoses (MPS) I and VI, and dogs with MPS VII were analyzed biochemically and morphometrically to determine the lysosomal storage of glycosaminoglycans (GAG) in these animal models of human genetic disease. Analyses were performed on liver samples from seven normal cats ranging in age from 13 weeks to 15 months; six MPS I-affected cats ranging in age from 10 weeks to 26 months; four MPS VI-affected cats ranging in age from 9 months to 32 months; four normal dogs ranging in age from 1 month to 47 months; and three MPS VII-affected dogs, 5 days, 11 days, and 14 months of age. All of the animals were from the breeding colony at the University of Pennsylvania School of Veterinary Medicine and were maintained in accordance with national standards for the care and use of laboratory animals. Each GAG subclass was quantitated, and total GAG concentration was determined. Liver from cats with MPS I had the highest total GAG concentration (5.7 times that of the control), followed by liver from dogs with MPS VII (1.8 times) and cats with MPS VI (1.5 times). These data were very closely correlated (R2 = 0.982) with the results of the morphometric analyses of hepatocyte and Kupffer cell vacuolation associated with lysosomal storage and support the validity of both methods. This is particularly important for the quantification of total and individual GAG concentrations in tissue preparations. The values obtained should prove useful in future assessments of therapeutic regimes, such as enzyme replacement, bone marrow transplantation, and gene therapy, for these genetic diseases.

Inherited selective intestinal cobalamin malabsorption and cobalamin deficiency in dogs.

Inherited selective intestinal malabsorption of cobalamin (Cbl) was observed in a family of giant schnauzer dogs. Family studies and breeding experiments demonstrated simple autosomal recessive inheritance of this disease. Affected puppies exhibited chronic inappetence and failure to thrive beginning between 6 and 12 wk of age. Neutropenia with hypersegmentation, anemia with anisocytosis and poikilocytosis, and megaloblastic changes of the bone marrow were present. Serum Cbl concentrations were low, and methylmalonic aciduria and homocysteinemia were present. Parenteral, but not oral, cyanocobalamin administration rapidly eliminated all signs of Cbl deficiency except for low serum Cbl concentrations. Cbl malabsorption in affected dogs was documented by oral administration of [57Co]cyanocobalamin with or without simultaneous oral administration of intrinsic factor or normal dog gastric juice. Quantitation and function studies of intrinsic factor and transcobalamin-II from affected dogs revealed no abnormality. Other gastrointestinal functions and ileal morphology were normal, indicating a selective defect of Cbl absorption at the level of the ileal enterocyte. Immunoelectron microscopy of ileal biopsies showed that the receptor for intrinsic factor-Cbl complex was absent from the apical brush border microvillus pits of affected dogs. This canine disorder resembles inherited selective intestinal Cbl malabsorption (Imerslund-Gräsbeck syndrome) in humans, and is a spontaneously occurring animal model of early onset Cbl deficiency.

X-linked severe combined immunodeficiency in the dog.

This study documents the occurrence of a form of X-linked severe combined immunodeficiency (SCID) in the dog with clinical, immunologic, and pathologic features similar to those of X-linked SCID with B cells in man. The disease in the dog is characterized by growth retardation and increased susceptibility to bacterial and viral infections in young pups. Affected pups have all died or were euthanatized by 5 months with signs of canine distemper, infectious hepatitis, or bacterial pneumonia. Laboratory findings include normal numbers of circulating B lymphocytes and normal concentrations of serum IgM, but low to absent concentrations of serum IgG and IgA, indicating a defect in the terminal differentiation of IgG and IgA B cells into immunoglobulin-secreting plasma cells. This is supported by the failure of peripheral lymphocytes to produce IgG or IgA plaque-forming cells in response to polyclonal activation. There are low-to-normal numbers of circulating T cells, but a severely depressed blastogenic response to T cell mitogens. Postmortem findings include thymic dysplasia and hypoplasia of lymphoid tissue. Family studies and breeding experiments are consistent with an X-linked recessive mode of inheritance.

Organic aciduria and butyryl CoA dehydrogenase deficiency in BALB/cByJ mice.

A metabolic screening program of inbred strains of mice has detected a marked organic aciduria in the BALB/cByJ strain. Gas chromatographic and mass spectrometric analysis identified large quantities of n-butyrylglycine plus lesser quantities of ethylmalonic acid. Crosses with the nonexcreting C57BL/6J strain indicate that this condition is inherited as an autosomal recessive trait. Independently from this screening a variant with no detectable enzyme activity of butyryl CoA dehydrogenase (BCD) in liver and kidney of the BALB/cByJ strain but not other BALB/c sublines was discovered. Data from a three-point cross indicated that the null variant maps to the structural locus for the enzyme, Bcd-1, on chromosome 5. The findings indicate that a mutation at or near Bcd-1 in the BALB/cByJ strain resulted in a biochemical abnormality manifest as the BCD deficiency. It is concluded that accumulation of butyryl CoA due to a block in the oxidation of short-chain fatty acids results in an overproduction of organic metabolites leading to the observed organic aciduria. The fact that other BALB/c substrains do not exhibit this abnormality further suggests that this disorder reflects subline divergence within the BALB/c family.

Alpha-mannosidosis in a Persian cat.

Alpha-mannosidosis, an inherited enzyme-deficiency disease, caused growth retardation, hepatomegaly, ocular abnormalities, and neurologic dysfunction in a Persian cat. Because of the clinical progression of this autosomal recessive, lysosomal storage disorder, the cat was euthanatized at 5 months of age.

Lethal acrodermatitis in bull terriers.

A lethal syndrome characterized clinically by growth retardation, progressive acrodermatitis, chronic pyoderma and paronychia, diarrhea, pneumonia, and abnormal behavior was observed in 17 related Bull Terrier pups. Median survival time was 7 months. Laboratory evaluation revealed non-degenerative neutrophilia, consistently low activities of serum alkaline phosphatase and alanine transaminase, and frequently, hypercholesterolemia. Lymphocyte blastogenic responses were decreased and there was dysgammaglobulinemia in pups in which quantitative studies of immunoglobulins were made. The mean of plasma zinc concentrations in 5 affected pups was significantly lower than the mean of age- and breed-matched controls. Pathologic findings included parakeratosis, hyperkeratosis, and superficial bacterial infections of the skin. There was severe reduction of lymphocytes in T-lymphocyte areas of lymphoid tissue. Bronchopneumonia and dilatation of the cerebral ventricles were found in most affected pups. Family studies indicated that the syndrome is inherited as an autosomal recessive trait. In spite of its similarities to lethal trait A46 in Black Pied Danish cattle and acrodermatitis enteropathica in man, oral or parenteral treatment with zinc failed to ameliorate the clinical signs of the syndrome.

Selective IgA deficiency in the dog.

This study documents the occurrence of selective IgA deficiency in the dog. This is a unique spontaneous animal model with clinical and immunologic findings similar to that of selective IgA deficiency in humans, the most common human primary immunodeficiency. The disease in the dog is characterized by chronic, recurrent respiratory infections and dermatitis, low concentrations of serum IgA, normal concentrations of serum IgG and IgM, normal T-cell function as measured by lymphocyte transformation tests, the presence of autoantibodies, and a defect in the maturation or terminal differentiation of IgA B cells into IgA-secreting plasma cells.

Beta-glucuronidase deficiency in a dog: a model of human mucopolysaccharidosis VII.

This report describes a third mucopolysaccharidosis in animals: canine mucopolysaccharidosis VII. The affected dog was the offspring of a father-daughter mating. Weakness in the rear legs was evident at 8 weeks of age and became progressively worse. He had a large head, a shortened maxilla, and corneal granularities. Most joints were extremely lax, easily subluxated, with joint capsules that were swollen and fluctuant. The dog was alert and had apparently normal pain perception. At 13 months of age, there was radiographic evidence of extensive skeletal disease including bilateral femoral head luxation, abnormalities in the shape and density of the carpal and tarsal bones, radiolucent lesions of the epiphyseal regions of most long bones, and cervical vertebral dysplasia and platyspondylia. The electrophoretic pattern of precipitated glycosaminoglycans indicated a predominance of chondroitin sulfate. The animal died suddenly from gastric dilatation. There was generalized hepatomegaly, thickening of the atrioventricular heart valves, and generalized polyarthropathy. Vacuolated cytoplasm was observed in hepatocytes, keratocytes, fibroblasts, chondrocytes and cells of the synovial membrane, retinal pigment epithelium, and cardiac valves. Neurons had cytoplasmic vacuoles. Electron microscopy demonstrated membrane-bound cytoplasmic inclusions in polymorphonuclear leukocytes, hepatocytes, synovium, heart valves and spleen. The activities of 12 lysosomal hydrolases were determined in liver from the affected and control dogs: beta-glucuronidase (EC 3.2.1.31), beta-hexosaminidases A and B (EC 3.2.1.30), alpha-hexosaminidase (EC 3.2.1.-), alpha-L-iduronidase (EC 3.2.1.76), alpha-galactosidase A (EC 3.2.1.22), beta-galactosidase (EC 3.2.1.23), arylsulfatases A and B (EC 3.1.6.1), acid alpha-mannosidase (EC 3.2.1.24), acid beta-mannosidase (EC 3.2.1.25), and N-acetyl-D-galactosamine-6-sulfate sulfatase (EC 3.1.6.-).(ABSTRACT TRUNCATED AT 250 WORDS)

Polyclonal activation of canine B lymphocytes evaluated by a protein A reverse hemolytic plaque assay.

This paper describes the optimal culture and assay conditions for the polyclonal activation of canine lymphocytes with pokeweed mitogen and the quantitation of immunoglobulin secreting plaque-forming cells (PFC) using a staphylococcal protein A-reverse hemolytic plaque assay. The assay permits the quantitation of total immunoglobulin secreting PFC as well as class-specific immunoglobulin secreting PFC. On the optimal day of culture, a mean of 176 IgA PFC/10(6), 575 IgM PFC/10(6), 1276 IgG PFC/10(6), and 2158 total PFC/10(6) cells were generated following polyclonal activation. This study provides a simple and reproducible assay for the delineation of the immunoregulatory mechanisms involved in the differentiation of canine B lymphocytes.

Postnatal development of renal tubular amino acid reabsorption in canine pups.

The renal clearance of amino acids in canine pups 5 days and 3, 8, and 12 weeks of age was studied. The 5-day-old pups had incomplete reabsorption of most amino acids. At 3 weeks, fractional reabsorption of 16 of 21 amino acids was complete; between 3 and 8 weeks, an adult pattern of reabsorption was present. Seemingly, a rapid development of amino acid transport precedes anatomic development or functional maturation of other transport systems.

Short-limbed dwarfism and ocular defects in the Samoyed dog.

A syndrome of short-limbed dwarfism and ocular defects was found in Samoyed dogs. The most prominent abnormalities were small stature and valgus deformity of the carpi. Radiographic evidence of retarded growth at the distal ulnar physis was apparent by 12 weeks of age. Ocular defects included cataracts and retinal detachment. Family studies and limited breeding experiments were consistent with an autosomal recessive mode of inheritance.