A murine model of the eosinophilia-myalgia syndrome induced by 1,1'-ethylidenebis (L-tryptophan).

The eosinophilia-myalgia syndrome (EMS) is a recently described disease that has been associated with the ingestion of L-tryptophan containing trace amounts of several impurities. The first such contaminant to be identified and linked epidemiologically to the EMS epidemic was 1,1'-ethylidenebis(L-tryptophan) (EBT), but its role in the etiology and pathogenesis of the syndrome has been controversial. We report the development of inflammation and fibrosis affecting the dermis and subcutis, including the fascia and perimyseal tissues, after the daily intraperitoneal administration of EBT to female C57BL/6 mice. Such changes are accompanied by increased numbers of mast cells, many of which appear to be degranulating. Plasma levels of quinolinic acid, a metabolic product of L-tryptophan via the kynurenine pathway, are reduced initially, and then become elevated when inflammation and fibrosis are more pronounced. The nature and location of the inflammatory cell infiltrate and fibrosis, as well as the presence of mast cells and alterations of L-tryptophan metabolism, are consistent with findings reported in patients with EMS. This murine model suggests that EBT may have been one of the mediators of EMS and should facilitate studies of the pathogenesis of EMS.

A murine model of prenatal cocaine exposure: effects on the mother and the fetus.

To develop and characterize a murine model for investigating the long-term effects of prenatal cocaine exposure, the present study established the route of drug administration and the doses to be used for pregnant C57BL/6 mice. Comparison of the effects of a high dose of cocaine (60 mg/kg) when gavaged or injected subcutaneously (SC) established patterns of pathology characteristic of administration route but no dominating logic for selecting one over the other route for prenatal studies; however, because of the fourfold greater brain levels, with no evidence of greater pathology, the SC route was selected. When injected daily during gestation days 12-18, the period of prenatal development of dopamine systems, cocaine at doses producing plasma concentrations consistent with its stimulatory effects reduced food ingestion and weight gains during pregnancy and fetal body and brain weights at term. The extent of these reductions was comparable to reports on babies exposed to cocaine prenatally. Furthermore, the present study suggests that maternal undernutrition is not a likely mediator of these perinatal effects and that differences in the amount of cocaine exposure may cause the contrasting effects of maternal cocaine noted in the human literature.

Chondrodysplasia in five Great Pyrenees.

Five disproportionate, short-limbed, short-trunked (dwarf) Great Pyrenees pups were examined. The mode of inheritance was compatible with a simple autosomal recessive trait, and skeletal radiography revealed flaring of the metaphyses of all long bones and the costochondral junctions of the ribs. Vertebral bodies were poorly ossified and short, and had a beak-like extension on the caudal metaphyseal margin. Vertebral body end-plates were thin and concave, and ossification was abnormal. Three of the 5 dogs were deaf, and 1 had testicular atrophy. Ocular examinations did not reveal any abnormalities. Histologic examination of the growth plates revealed disorganized chondrocyte columns, and chondrocytes appeared to have undergone degenerative changes in the zone of chondrocyte proliferation. Transmission electron micrography of growth plate chondrocytes revealed dilated profiles of rough endoplasmic reticulum.

Spinal cord compression and hindlimb paresis in cats with mucopolysaccharidosis VI.

Six cats with mucopolysaccharidosis VI had hindlimb paresis and other clinical signs associated with compression of the thoracolumbar spinal cord. In 5 cats, the neurologic abnormality progressed over 2 to 4 weeks to loss of thoracolumbar spinal cord function. In 1 cat, the hindlimb paresis remained stable for 18 months. In the cats with progressive worsening of hindlimb function, the abnormality was caused by compression of the spinal cord from proliferation of bony tissue in the thoracolumbar region. In all affected cats, the compression occurred from T12 to L2. In 1 cat, an attempt to relieve the clinical signs by surgery was unsuccessful.

Chondrodysplasia in the Norwegian Elkhound.

Dwarfism in the Norwegian Elkhound occurred as a result of a generalized disturbance in endochondral ossification. Radiographic changes included flaring and increased width of the distal metaphyses of the radius and ulna, delayed ossification of the cuboid bones of the carpus, and reduction in length of the vertebral bodies. The zone of chondrocyte proliferation was decreased in width and contained areas of abnormal cell column formation alternated with wide areas of matrix. Chondrocytes in all zones contained one or more inclusions bounded by a smooth discontinuous membrane. The material within the inclusions appeared homogeneous and stained blue-green with Movat's pentachrome and deep blue with alcian blue-periodic acid-Schiff at pH 1.0 and 2.6. The distribution of ruthenium red granules in the matrix frequently revealed poor differentiation into territorial and interterritorial zones. Twenty-four-hour urine samples were negative for glucose, and the glycosaminoglycan excretion pattern was normal.

Studies of the intercellular matrix of growth plates from dwarf and homozygous nonaffected Alaskan Malamutes: collagen and hexosamine.

This study was performed to compare the extractability of dwarf growth plate collagen and hexosamine and that of homozygous nonaffected Malamutes and to measure the activity of three of the enzymes involved in the post-translational modifications of the collagen molecule. No significant differences were found in the activity of prolyl hydroxylase or lysyl oxidase in the dwarf growth plates. Lysyl hydroxylase activity in the dwarf was decreased to 22% and 33% that of the activity present in the homozygous nonaffected growth plates. Amino acid analysis of the collagen isolated from dwarf growth plates failed to reveal any decrease in hydroxylysine content. Growth plates were extracted with either 1 M sodium chloride or 4 M guanidine hydrochloride. The extracts were applied to a DEAE-cellulose column. Amino acid analyses of the material which did not bind to DEAE revealed a slight decrease in the amount of guanidine-extractable hydroxyproline in the dwarf but a 60-fold increase in the amount of salt-extractable hydroxyproline in the dwarf growth plates. Material which eluted with 1 M sodium choloride was analyzed for hexosamine. There was a 10-fold increase in the amount of salt-extractable hexosamine present in the dwarf growth plates, whereas no significant differences were observed in the guanidine-extracted material. Hexosamine analysis of the growth plates revealed a significant increase in the total amount of hexosamine present in the dwarf growth plates. SDS-polyacrylamide gels of the material which did not bind to DEAE as well as the pepsin digested, 0.9M sodium chloride precipitated collagen demonstrated the presence of only type II collagen.

Dwarfism in the Alaskan Malamute: ultrastructural features of dwarf growth plate chondrocytes.

This study was performed in order to reexamine the ultrastructural morphology of the chondrocytes in the growth plates of dwarf Alaskan Malamutes and to obtain semiquantitative cytochemical data about the proteoglycans. Growth plates from age-matched dwarf and homozygous nonaffected Alaskan Malamutes were processed for routine transmission electron microscopy and also stained with ruthenium red. Chondrocytes in dwarf plates were observed to occur in clumps or cell nests. Within some of these nests, chondrocytes in the upper half of the zone of chondrocyte proliferation had bizarre shapes ranging from V-shaped to whorled or rounded. These chondrocytes contained profiles of markedly dilated rough endoplasmic reticulum (RER). Material within the RER cisternae stained positively with ruthenium red and was partially digestible with testicular hyaluronidase. The material could, therefore, represent either chondroitin sulfate or hyaluronate. The RER in these dwarf chondrocytes was not oriented parallel to the long axis of the cells; instead, it consisted of irregularly dilated cisternae. Granule counts performed on the zone of chondrocyte proliferation revealed a significant decrease in the number of ruthenium red granules in the interterritorial matrix of dwarf chondrocytes when compared to those of the homozygous nonaffected chondrocytes.

Chondrodysplasia in the Alaskan malamute. Characterization of proteoglycans dissociatively extracted from dwarf growth plates.

Proteoglycan monomers obtained from the dissociative extraction of growth plate cartilages of chondrodysplastic and homozygous nonaffected Alaskan malamute dogs were characterized with regard to hydrodynamic size and glycosaminoglycan composition. Dissociative extraction solubilized 91.7% of the uronic acid and 71.7% of the protein from dwarf growth plates compared to 76.8% of the uronic acid and 50.2% of the protein from normal growth plates. Dissociative density gradient ultracentrifugation of the extracts resulted in the recovery of 84% of the uronic acid from dwarf growth plates and 71% of the uronic acid from normal growth plates in the D1 fraction. High-pressure liquid chromatography of the dwarf D1 monomers revealed a single peak with a retention time of 8.6 minutes while the normal D1 monomers eluted later with a retention time of 8.9 minutes. After reduction of the dwarf D1 monomers, the chondroitin sulfate side chains eluted from Sepharose CL-6B with an approximate molecular weight of 15,000 (Kav of 0.55) while those from the normal eluted with an estimated molecular weight of 9,500 (Kav of 0.64). High-pressure liquid chromatography analysis of the unsaturated disaccharides from the dwarf D1 fractions revealed increased amounts of chondroitin-6-sulfate. Analysis of the fractions for glucosamine and galactosamine revealed that dwarf D1 and D2 fractions were enriched in galactosamine. These findings indicate that the extracellular matrices of dwarf growth plates contain proteoglycan monomers which may be indicative of a less mature extracellular cartilage matrix than the cartilage matrices of age-matched normal dogs.

Undersulfated chondroitin sulfate in cartilage from a miniature poodle with spondyloepiphyseal dysplasia.

In order to determine if either the proteoglycans or collagen in the cartilagenous epiphyses of a Miniature Poodle with spondyloepiphyseal dysplasia were abnormal, the cartilage was dissociatively extracted in 4 M guanidine HCl in the presence of protease inhibitors and subjected to isopycnic cesium chloride dissociative density gradient ultracentrifugation. Dissociative extraction solubilized 97% of the uronic acid and 88% of the protein. Uronic acid distributed anomalously in the density gradient in that about 1/3 was recovered in each of the D1 (1.58 g/ml), D2 (1.49 g/ml) and D3 (1.44 g/ml) fractions. Proteoglycans in the D1, D2 and D3 fractions also eluted from Sepharose CL-2B columns in a manner indicative of monomers of a smaller apparent hydrodynamic size than those from normal canine growth plate or articular cartilage. D1, D2 and D3 monomers subjected to the sodium borohydride reaction followed by chromatography on a Sepharose CL-6B column yielded glycosaminoglycan chain molecular weights of 10,200 (D1), 7600 (D2) and 6200 (D3). High pressure liquid chromatography on a Whatman Partisil 10PAC column of the chondroitinase AC II digests of D1, D2 and D3 fractions revealed that 60% of the D1, 81% of the D2 and 88% of the D3 unsaturated disaccharides eluted in the delta DiOS-delta DiHA position. Subsequent HPLC of the unsaturated disaccharides on the Hypersil APS column resulted in the recovery of 97% of the nonsulfated unsaturated disaccharides in the delta DiOS position. Associative extraction in 0.5 M guanidine followed by associative gradient ultracentrifugation resulted in the recovery of 27% of the uronic acid in the aA1 and 47% in the aA2 fractions. Two dimensional SDS gel electrophoresis of the CNBr peptides of the collagen isolated by pepsin digestion and 0.9 M NaCl precipitation revealed type II collagen. This study has demonstrated that spondyloepiphyseal dysplasia in a Miniature Poodle is characterized by cartilage containing undersulfated chondroitin sulfate proteoglycan.

Survival curves, reproductive life span and age-related pathology of Mus caroli.

Although Mus caroli is being used in a number of laboratories as an experimental animal, basic information concerning its life span, reproductive ability, and age-related pathologies has been unavailable. Here we present this basic information, and discuss the similarities to and differences from the laboratory mouse, Mus musculus domesticus [strains A/StTrWo and (A/StTrWo x C57BL/6NNia)F1] and, from published data, wild-type Mus musculus.

Chronic sialodacryoadenitis virus (SDAV) infection in athymic rats.

Sialodacryoadenitis virus (SDAV) was detected in athymic rats subcutaneously implanted with human tumor cell lines. Clinical signs included sneezing, dyspnea, weight loss and death. Necropsy revealed both upper and lower respiratory tract disease from which Staphylococcus aureus, Pasteurella pneumotropica and Pseudomonas aeruginosa were recovered. Histopathological changes consisted of suppurative rhinitis and bronchopneumonia. Lesions characteristic of SDAV infection were found in lacrimal and salivary glands, and viral antigens were detected in the salivary glands and respiratory tract by immunohistochemistry. Submaxillary salivary gland. Harderian gland and lung homogenates from affected athymic rats were inoculated intranasally into euthymic rats as a rat antibody production test. All euthymic rats seroconverted to SDAV. Seroconversion to SDAV was demonstrated in consecutive pairs of sentinel euthymic rats housed for 6 months with infected athymic rats. Inoculation of supernatants of the original tumor cell lines into euthymic rats did not result in seroconversion. The source of the virus was not determined. In this study, spontaneously acquired SDAV infection persisted for at least 6 months in athymic rats.