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Biomedical subjects

J E van Dijk

Publications and source records attributed to J E van Dijk.

At least 37 records · Page 2Linked to original sources
PubMed1995

Virulence and genotype of a bovine herpesvirus 1 isolate from semen of a subclinically infected bull.

A bovine herpesvirus 1 (BHV-1) isolate from the semen of a subclinically infected bull was administered to cattle by various routes to assess its virulence. Cattle that were artificially inseminated or inoculated intrapreputially did not develop clinical signs, but did transmit the virus to contact cattle. However, the isolate induced severe signs of rhinotracheitis and vulvovaginitis in cattle that were inoculated by the intravaginal, intranasal or intravenous routes, but did not infect the fetus. The isolate was therefore not of low virulence. Analysis with DNA restriction enzymes could not assign the isolate to either the BHV-1.1 or BHV-1.2 genotype.

Animals↗
PubMed1995

Spleen pigmentation in young C57BL mice is caused by accumulation of melanin.

It has been previously reported that in 2 C57BL mouse sublines a dark pigmentation of the cranial part of the spleen occurs in up to 30% of the animals within the populations. It was not clear whether this discoloration is caused by melanosis, lipofuscinosis or haemosiderosis. With the use of light and electron microscopy of stained spleen sections, we identified the pigment in 14 out of 60 C57BL mice aged 8-10 wks. In the mice with pigmented spleens there was accumulation of melanin, predominantly in melanophores. Literature data indicate that apart from melanin, lipofuscin and haemosiderin can be observed in splenic macrophages provided that the mice are older than those studied by us. We conclude that melanin is the principal pigment causing spleen discoloration in young C57BL mice. Splenic melanosis displays inter-individual variation, but its relevance from a pathophysiological point of view remains obscure.

Animals↗
PubMed1993

Tight junctional structure and permeability of porcine jejunum after enterotoxic Escherichia coli infection.

Tight junctional structure and macromolecular permeability were tested in four three-week-old piglets, experimentally infected with the enterotoxigenic Escherichia coli (ETEC) strain O149 K91 K88. Histologically, only minor microscopic evidence of inflammation and little or no architectural changes in the jejunal mucosa were observed. A significant decrease in tight junctional strand numbers occurred, without a concomitant decrease in tight junctional depth. The permeability of the porcine jejunal epithelium to horseradish peroxidase did not change after the ETEC infection.

Animals↗
PubMed1993

Comparison of pathological signs of disease in specific-pathogen-free calves after inoculation of the respiratory tract with Ureaplasma diversum or Mycoplasma canis.

To confirm the pathogenic role of Ureaplasma diversum in respiratory disease of calves, we inoculated caesarean-delivered, colostrum-deprived calves intranasally with a dose of 10(7) colour-changing units (CCU) or endobronchially with a dose of 10(10) CCU. Clinical signs of respiratory disease were not observed, but in the endobronchially inoculated calves, thick cuffs of round cells surrounded the bronchi, bronchioli and blood vessels, and a lobular catarrhal pneumonia developed. It was concluded that the pathogenicity of U. diversum can be demonstrated after endobronchial but not after intranasal inoculation. Similar calves were inoculated endobronchially with a dose of 2 x 10(10) colony-forming units of Mycoplasma canis. Clinical signs of respiratory disease were not observed. At day 2 after inoculation, only slight pathological signs of respiratory disease were detected, and these disappeared at day 9. M. canis was not recovered from the lungs. Hence, M. canis could not be clearly identified as a pathogen in respiratory disease of calves. By comparing the results of the various experiments, we concluded that thin cuffs of round cells in the lungs can indicate mycoplasma infections, but that these are not necessarily pathognomonic.

Animals↗
PubMed1992

Determination of concentrations by time domain fitting of proton NMR echo signals using prior knowledge.

A fast and flexible time domain iterative fitting procedure that can be used to fit free induction decays as well as echo-like signals is described. Damping constants of the first and second part of the echo do not have to be identical. Prior knowledge can be used to diminish the number of parameters to be fitted, which results in an improved accuracy. It is shown how prior knowledge is mathematically incorporated in the Gauss-Newton method. From proton NMR measurements of model solutions actual prior knowledge is extracted. With this knowledge relative concentrations are determined from a mixture of metabolites. The fitted results agree with the true values within the margins of the noise. After some minor changes the same prior knowledge was successfully used to analyze a series of in vivo rat brain measurements.

Magnetic Resonance Spectroscopy↗
PubMed1992

Malignant fibrous histiocytomas in dogs and cats: an immunohistochemical study.

Immunohistochemical staining was performed on seven canine and 10 feline soft tissue tumours histologically diagnosed as malignant fibrous histiocytomas (MFHs) or MFH-like tumours, and eight other histologically specified tumours (non-MFH). This was done to determine if commercially available antibodies that are used routinely in human diagnostic pathology for MFHs would express the same immunohistochemical patterns in canine and feline MFHs and MFH-like tumours. The antibodies were directed against human alpha 1-anti-trypsin (AT), human alpha 1-anti-chymotrypsin (ACT), human lysozyme, bovine S-100 protein and human desmin. AT did not show any immunoreactivity in the tissues investigated. Except for one MFH, all canine MFHs and other soft tissue tumours with a 'histiocytic' character stained for lysozyme and not for S-100. Six out of seven canine MFHs and MFH-like tumours stained positive for desmin as did most non-MFH sarcomas. Most of the canine and feline MFHs and MFH-like tumours were positive for ACT. These findings for ACT staining in canine and feline MFHs and MFH-like tumours are in agreement with the findings in human MFHs. The immunohistochemical results of canine MFHs and MFH-like tumours were different from those in cats. Feline MFHs differed from canine MFHs for both lysozyme and desmin staining.

Animals↗
PubMed1992

Thickening of the glycocalyx during methotrexate induced small intestinal mucosal atrophy in the rat.

In this study, the morphology of the glycocalyx of small intestinal enterocytes in the rat was investigated after the induction of mucosal atrophy by methotrexate (MTX) in 18 Wistar rats. On the 2nd, 4th and 6th day after the intraperitoneal administration of MTX, a group of 6 rats was sacrificed and tissue specimens taken at the level of the Treitz' ligament were post fixed in a mixture of 2.0% watery osmiumtetroxide and 1.5% potassium-ferrocyanide to enhance visibility of glycoconjugates and processed for electron microscopy. In the control rats, the glycocalyx was hardly visible on the villous enterocytes, but rather conspicuous on the enterocytes in the crypts. On the second day after injection of MTX, the glycocalyx of the villous enterocytes was more pronounced but on the crypt enterocytes it resembled that of control animals. On the 4th day after MTX administration, a striking reduction and shortening of microvilli of villous enterocytes was seen, together with very pronounced glycocalyces, while crypt cells possessed well developed cell coats. On the 6th day after the injection of MTX, the glycocalyx of both villous and crypt cells appeared almost normal again.

Animals↗
PubMed1992

Virulence of Streptococcus suis type 2 strains in newborn germfree pigs depends on phenotype.

To determine whether the virulence of Streptococcus suis type 2 is associated with the phenotype of the strain, we infected newborn germfree pigs with 10 strains of S. suis type 2 categorized by three phenotypes. In an earlier study, the phenotypes were distinguished by the presence or absence of the muramidase-released protein (MRP) and an extracellular factor (EF) and were designated MRP+ EF+, MRP+ EF- and MRP- EF-. Pigs were first inoculated with Bordetella bronchiseptica to predispose them to infection and were then intranasally inoculated with the streptococci. Strains of the MRP+ EF+ phenotype induced fever and increased the number of polymorphonuclear leukocytes in blood. Specific clinical signs of disease such as nervous disorders and lameness were also observed. At necropsy bacteriologic and pathologic examination disclosed meningoencephalitis, polyserositis, and polyarthritis. Strains of the MRP+ EF- phenotype induced only nonspecific clinical signs of disease such as recumbency, lack of appetite, and fever; only slight pathologic changes were detected in the serosae. The four strains of the MRP- EF- phenotype induced no signs of disease. These findings indicate that the 110-kDa EF and, to a lesser degree, the 136-kDa MRP may be associated with the virulence of the bacterium. The results demonstrated that S. suis type 2 strains producing both MRP and EF are pathogenic for pigs.

Animals↗
PubMed1992

Thyroid albumin originates from blood.

Iodoalbumin has been found in the goiter of Dutch goats with a thyroglobulin synthesis defect. Immunohistochemical studies showed that in the goiter the percentage of follicles containing albumin was higher than that in normal thyroid glands. In the albumin-containing follicles of normal and goitrous glands, transferrin and immunoglobulin G could be found. Also, between the epithelial cells, serum proteins were detected. These results indicate intercellular passage of serum proteins. After in vivo labeling with 125I, goiter slices were incubated with [3H] leucine. Purified 125I-containing albumin did not contain [3H]leucine, while thyroglobulin antigens were double labeled. Cyanogen bromide treatment of albumin out of the goiter and of serum albumin gave comparable cleavage patterns, indicating that no great differences in amino acid composition, especially methionine, exist. In total RNA from goiter, no albumin mRNA could be detected after blotting and hybridization with goat albumin cDNA. Also, the polymerase chain reaction method with albumin DNA primers was unable to detect any albumin mRNA in normal and goitrous glands of goats. From these results we conclude that "thyralbumin" originates from blood and is not synthesized by the thyroid gland.

Animals↗
PubMed1992

Intestinal permeability in pigs during rotavirus infection.

Macromolecular permeability of the small intestine was tested in four 3-week-old gnotobiotic pigs inoculated with porcine rotavirus strain RV277 (group A). Pigs were administered 125I-labeled polyvinylpyrrolidone (molecular weight [mol wt], 40,000) orally 1 day before and 2 and 24 hours after virus inoculation, and blood samples were obtained every 6 hours. Eight hours after rotavirus inoculation, pigs had watery diarrhea. Increased permeation of 125I-labeled polyvinylpyrrolidone was not observed after clinical signs of infection had developed. Serum total protein and urea nitrogen concentrations increased slightly at the end of the study, probably as a consequence of dehydration. Differences in blood glucose concentration were not seen. At 48 hours after viral inoculation, macromolecular permeability was tested morphologically by injecting horseradish peroxidase (mol wt, 40,000) into the jejunal lumen just distally to the ligamentum colicoduodenale. After an incubation period of 20 minutes, small segments of jejunum were obtained for stereomicroscopic, histologic, and ultrastructural investigations. Moderate hyperregenerative villus atrophy was found. Ultrastructural changes of the villus epithelium were minor, and increased macromolecular permeation was not observed.

Animals↗
PubMed1991

The role of the common vole (Microtus arvalis) in the epidemiology of bovine infection with Leptospira interrogans serovar hardjo.

Control of leptospirosis in cattle depends on the presence of other possible maintenance hosts, with which cattle may have contact. Twenty-seven common voles (Microtus arvalis) were trapped on a dairy farm where the cattle were infected with Leptospira interrogans serovar hardjo (hardjo). In the sera of 11 voles, titres greater than or equal to 100 against serogroup Grippotyphosa were measured with the microscopical agglutination test (MAT). From 8 of these 11 voles, which also showed interstitial lymphoplasmacellular nephritis, Leptospira interrogans serovar grippotyphosa was isolated. We found no evidence that the common vole is a maintenance host for hardjo in this biotope.

Agglutination Tests↗
PubMed1991

Pathological, ultrastructural, and immunohistochemical changes caused by Lelystad virus in experimentally induced infections of mystery swine disease (synonym: porcine epidemic abortion and respiratory syndrome (PEARS)).

The pathogenicity and pathogenesis of Lelystad virus was studied in six 6-day-old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re-isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the target organ for this virus, macrophages in other organs, such as the spleen, can also be infected. This preference for macrophages may impair immunological defences.

Abortion, Veterinary↗