PubMed Health⌕ Search

Biomedical subjects

J E van Dijk

Publications and source records attributed to J E van Dijk.

At least 55 records · Page 3Linked to original sources
PubMed1991

Intestinal permeability in piglets during transmissible gastroenteritis.

Macromolecular permeability of the small intestine was tested in seven three-week-old piglets infected with porcine transmissible gastroenteritis virus (TGE-strain Miller). Fourteen hours after the infection, the piglets showed loss of appetite and a profuse diarrhoea. In some animals vomiting occurred somewhat earlier. Macromolecular permeability was tested morphologically by injecting horseradish peroxidase (MW = 40,000 Da) into the jejunal lumen just distally to the Treitz' ligament in two piglets at 12 hours and in five piglets at 48 hours after the inoculation in comparison with two control piglets. After a period of 20 minutes, small segments of jejunum were taken for stereomicro-scopical, histological and ultrastructural investigations. An increased permeability for HRP together with a severe, hyper-regenerative villous atrophy was observed in the TGE-infected piglets at 48 hours after the inoculation.

Animals↗
PubMed1991

Circulating thyroglobulin measurements by homologous radioimmunoassay in dogs with thyroid carcinoma.

Circulating thyroglobulin was measured in 20 dogs with thyroid cancer, using a homologous polyclonal radioimmunoassay. Plasma Tg levels exceeded the normal range in 14 (70%) dogs, and ranged from 6 to 2902 micrograms/l (median 608). Plasma Tg levels tended to decrease from follicular carcinomas to solid-follicular carcinomas, to solid carcinomas (p less than 0.05). Plasma Tg levels were also higher in scintigraphically hot tumours than in cold ones. Other relationships between circulating Tg and clinical, pathological, and functional parameters were not found, except a poor (R = 0.49) but significant (p = 0.04) correlation between Tg and T4 levels. Plasma Tg was measured before surgery and at least once during follow-up, in 9 dogs. After hemithyroidectomy, a decrease was observed in 8 dogs. In 7 of these 8 dogs, plasma Tg levels declined within the reference range at the first postoperative sample. In the ninth dog, where metastases were detected 14 months after surgical treatment, plasma Tg slightly increased, yet within normal range. It is concluded that measurement of plasma Tg levels might be useful for monitoring the postoperative course of the disease in individual dogs with thyroid cancer.

Adenoma↗
PubMed1991

Congenital hypothyroidism in two cats due to defective organification: data suggesting loosely anchored thyroperoxidase.

Two cats with congenital hypothyroidism are described. In vivo discharge of accumulated labelled iodide by perchlorate administration revealed defective organification of iodide, which was complete in one cat and partial in the other. In the cat with the partial organification defect, thyroid tissue was obtained for biochemical studies. No membrane-bound peroxidase activity could be demonstrated. The activity was found in the 100,000 x g supernatant. It is suggested that the loose enzyme anchoring caused decreased availability of peroxidase and as a consequence reduced capacity for organic binding of trapped iodide.

Animals↗
PubMed1990

[Changes in the histochemical composition of mucins in goblet cells in the course of a Nippostrongylus brasiliensis infection in the rat].

Rats were infected with Nippostrongylus brasiliensis, and changes in the histochemical composition of mucins in jejunal goblet cells were investigated. Ten days after infection, mitotic activity was extensively in jejunal crypts: both crypts and villi were characterised by hyperplasia of goblet cells. Infected rats had a markedly greater number of crypt and villi goblet cells containing neutral mucin than the control rats did. Moreover, 15 days after infection, infected rats had significantly more goblet cells containing acid mucin than control rats did. In infected rats, the acid mucins in goblet cells (day 15) appeared to be predominantly sulphomucins, whereas in control rats the acid mucins were predominantly sialomucins. The experiments established that when N. brasiliensis is excreted by rats, the histochemical composition of mucins in crypt and villi goblet cells has been changed not only quantitatively, but also qualitatively.

Animals↗
PubMed1990

QUALITY: quantification improvement by converting lineshapes to the Lorentzian type.

A method of time domain deconvolution, QUALITY, is described for general use in quantitative NMR spectroscopy. By division of the experimental NMR time domain signal by a reference signal, which may be obtained either in a separate experiment or via inverse Fourier transformation of an isolated single resonance in the experimental spectrum, perfect Lorentzian lineshapes can be obtained regardless of the magnetic field inhomogeneity. Experiments, both in vivo using a surface coil and in vitro using a surface coil and a HR NMR probe, show excellent performance of the method.

Humans↗
PubMed1990

Comparison of a levamisole sustained-release bolus and ivermectin treatment to prevent bovine lungworm infection.

The efficacy of a levamisole sustained-release bolus to prevent parasitic bronchitis in calves in their first grazing season was compared to ivermectin treatment at three, eight and thirteen weeks after turn out. Contamination of the pasture was established by experimentally infected seeder calves. Twenty calves were split into two groups. Ten calves of one group received a bolus at the start of the experiment. In the other group the calves were treated with ivermectin at 21, 56 and 91 days. Two principal calves from each group were killed during the experiment to study histopathological changes. Pairs of tracer calves were introduced on both pastures at intervals of four weeks throughout the grazing period. The permanent calves were challenged with lungworm larvae at housing and slaughtered four weeks later. Both systems prevented parasitic bronchitis. Larval output was completely reduced in the ivermectin-treated calves while all bolus-treated calves excreted larvae at certain times. The highest group average was 4 larvae per gram faeces. Eosinophilia, ELISA-titres and histopathological changes confirmed the differences in larval uptake. Challenge infection was not successful in either group and no worms were found at slaughter. Weight gain was significantly different at housing in favour of the ivermectin-treated calves, but after challenge this was reduced due to a higher weight gain in the bolus-treated calves. The practical consequences of the results have been discussed.

Animals↗
PubMed1989

Intestinal permeability to polyethylene glycol 4000 and porcine albumin in piglets infected with transmissible gastroenteritis virus.

The intestinal permeability of specific pathogen free piglets has been studied by measuring the concentration of 14C in the blood after oral administration of 14C polyethylene glycol (14C PEG, MW = 4000) and the concentration of 131I in the faeces after intraperitoneal administration of 131I porcine albumin (131I PA, MW = 68,000). The tests were performed one day before and up to two days after the piglets were infected with transmissible gastroenteritis (TGE) virus. Jejunal biopsies were taken from two piglets before the experimental infection, from two piglets 12 h after the experimental infection and from five piglets at the end of the experiment, 46 h after infection. Blood samples were taken six-hourly and faecal samples several times. Some piglets vomited before diarrhoea and loss of appetite started at 14 h after infection; the packed cell volume decreased before but increased after infection. Morphological examination showed hyperregenerative villous atrophy at 46 h after infection. There was no increase in the permeation of 14C PEG but there was a significant increase in the flux of 131I PA from the blood to the gut lumen.

Administration, Oral↗
PubMed1989

The interaction between plant lectins and the small intestinal epithelium: a primary cause of intestinal disturbance.

The literature concerning the effects of plant lectins on the small intestinal epithelium is reviewed. It appears that after oral intake, intact plant lectins can reach the small intestinal lumen. Their binding to the mucosal surface evokes an increased synthesis of glycoproteins and a degeneration of the intestinal epithelium. The epithelial alterations may result in hyperregenerative villus atrophy and endogenous nitrogen loss. These changes ultimately can lead to less efficient feed conversion, diminished growth, scouring, wasting and death. The possible significance of plant lectins in digestive disturbances in farm animals is suggested.

Animals↗
PubMed1989

Normal-sized thyroglobulin messenger ribonucleic acid in Dutch goats with a thyroglobulin synthesis defect is translated into a 35,000 molecular weight N-terminal fragment.

The translation product of the thyroglobulin (Tg) mRNA in Dutch goats with a Tg synthesis defect has been characterized. The Tg mRNA has a normal size of 8.4 kilobases. Translation of goitrous polysomal Tg mRNA resulted, after immunoprecipitation with polyclonal rabbit antigoat Tg antibodies, in a single 35,000 mol wt (Mr) Tg fragment. To characterize the Tg antigens produced in vivo, thyroid hormone release by the goiter was suppressed by injecting T4 sc in newborn goitrous goats. Immunohistochemical studies showed the presence of Tg antigens almost solely in the colloidal lumen. Electrophoresis of the reduced thyroid proteins demonstrated the presence of two Tg fragments with Mr of 40,000 and 32,000, respectively; the latter is probably a breakdown product of the 40,000 Mr fragment. The difference in Mr between the in vivo and in vitro translation products (40,000 and 35,000 Mr, respectively) can be explained by the carbohydrate content (10% wt/wt) of the in vivo product, as was shown by periodic acid-Schiff-positive staining. Using monoclonal antibodies against the hormonogenic sites at the first and last parts of the Tg molecule, we demonstrated that only the first part of the Tg molecule is present. Both in vivo and in vitro 10% of the goitrous Tg mRNA molecule is translated, resulting in an N-terminal Tg fragment that easily aggregates to large S-S complexes in the colloidal lumen of goiter by H2O2 oxidation.

Animals↗
PubMed1988

Conjunctivitis, red nose and skin hypersensitivity as signs of food allergy in veal calves.

The severity of diarrhoea and the degree of hyperaemia of the conjunctiva and nose were recorded in veal calves being fattened on either cows milk or milk-replacer. A skin-prick test using the milk-replacer as antigen was also performed. Control calves received only their mother's milk. Among these control calves there were no abnormalities, and in the calves fed other cows milk only slight abnormalities were seen. In contrast, in the calves fattened on milk-replacer, and especially in the calves showing the 'cachexia' syndrome, there were moderate to severe abnormalities and clear correlations were found between the severity of the diarrhoea and the hyperaemia of the conjunctiva and nose, and the scores recorded in the skin-prick test.

Animals↗
PubMed1988

Intestinal permeability to macromolecules during colibacillosis in piglets.

Intestinal macromolecular permeability to macromolecules was determined in a group of specific pathogen free piglets before and after they were infected experimentally with Escherichia coli. Six hours after the infection all piglets developed a profuse diarrhoea. The urea and total protein concentrations in the serum increased markedly after the onset of diarrhoea. Haemoglobin concentration and PCV decreased steadily during the experiment but blood glucose concentration and lipid composition of the faeces did not change. No structural abnormalities in the jejunal and ileal mucosa were seen. No uptake of macromolecules (40,000 KDa) was found suggesting that molecules with a molecular weight of 40,000 or more do not play a role in the persistent diarrhoea sometimes seen in piglets after colibacillosis.

Animals↗
PubMed1988

Intestinal permeability to macromolecules in piglets infected with transmissible gastroenteritis virus.

The permeability of the intestine of specific pathogen free piglets was investigated by measuring the concentration of 125-I in the blood after oral administration of 125-I polyvinylpyrrolidone (125-I PVP, MW = 40,000 Da) and the concentration of 131-I in the faeces after intravenous administration of 131-I porcine albumin (131-I PA, MW = 68,000 Da). The tests were performed one day before and up to two days after the piglets were infected with the Miller strain of transmissible gastroenteritis (TGE) virus. Biopsies of the jejunum were taken at the end of the experiment and blood samples were taken six-hourly. The piglets became anorexic and had diarrhoea 12 hours after infection; the packed cell volume decreased and the concentrations of urea and total serum proteins increased slightly after infection. However, the marked villous atrophy was not accompanied by an increased permeability of the intestine to PVP or PA.

Albumins↗
PubMed1988

Nippostrongylus brasiliensis: histochemical changes in the composition of mucins in goblet cells during infection in rats.

Changes in the quality of mucins in jejunal goblet cells were investigated during an infection with Nippostrongylus brasiliensis in rats. At 10 days after infection, when proliferative activity in the crypts is excessive and both crypts and villi are characterized by hyperplasia of goblet cells, the histochemical composition of the population of goblet cells in comparison with controls shows a marked increase in crypt and villous goblet cells containing neutral mucins. At 15 days after infection both crypts and villi display a significant increase in goblet cells containing acid mucin and decrease in goblet cells containing neutral mucin. The acid mucins in crypt and villous goblet cells on day 15 appear to be sulphomucins predominantly, whereas in controls sialomucin-containing goblet cells dominate both in the crypts and on the villi. These experiments establish that the explusion of N. brasiliensis from the intestine of the rat coincides not only with quantitative, but also with remarkable qualitative changes in the histochemical composition of mucins in goblet cells.

Animals↗
PubMed1988

Histochemical changes in the composition of mucins in goblet cells during methotrexate-induced mucosal atrophy in rats.

Changes in the composition of mucins in jejunal goblet cells were investigated histochemically after a single intraperitoneal injection of methotrexate in rats (40 mg methotrexate/kg body weight). At 48 h after injection of methotrexate, when mitotic activity in the crypts approximates to zero, an almost complete disappearance of mucin-containing goblet cells can be observed. At 96h, when proliferative activity in crypts is excessive, neutral mucin- and sialomucin-containing goblet cells dominate in the crypts, whereas in controls the crypts display sulphomucin-containing goblet cells. At 144h neutral mucin- and sulphomucin-containing goblet cells dominate in the crypts. Both at 48 and 96h after injection of methotrexate a significant decrease in the number of villous goblet cells takes place, whereas with respect to the quality of the mucins in the goblet cells no difference can be found in comparison with control rats. At 144h the villi have recovered from the preceding temporary decrease of goblet cells. The histochemical composition of the population of goblet cells is still aberrant and shows goblet cells containing neutral mucins and sulphomucins principally, whereas in controls sialomucin-containing goblet cells dominate on the villi. The established changes in the composition of mucins in goblet cells cannot be attributed to methotrexate-induced malnutrition, as pair-fed control rats clearly demonstrate. Our results clearly demonstrate that conspicuous quantitative as well as qualitative changes in the synthesis of mucins in goblet cells occur during the hyporegenerative and hyperregenerative phase of methotrexate-induced mucosal atrophy.

Animals↗
PubMed1987

Quantitative determination of the lectin binding capacity of small intestinal brush-border membrane. An enzyme linked lectin sorbent assay (ELLSA).

A test to determine quantitatively the lectin binding sites in brush-border membranes has been developed. Highly purified bovine small intestinal brush-border membranes were prepared, and subsequently coated directly to the bottom of a microtiter plate. Soybean agglutinin conjugated with peroxidase was coupled to its binding sites in the brush-border membranes and the peroxidase activity was determined in a spectrophotometer. The number of soybean agglutinin binding sites in the brush-border membranes has been established by means of iterized computer fit analysis of the data, indicating values for maximal binding of 7.10(-7) M soybean agglutinin per mg of brush-border membrane protein and a dissociation constant of 1.5.10(-5) M.

Animals↗
PubMed1987

[Polyarteritis nodosa].

With reference to sixteen cases of polyarteritis nodosa (seven dogs, two cats, two goats, three pigs, two cattle), current views regarding classification, aetiology and pathogenesis of this disease are discussed. Polyartertis nodosa is not a disease entity, but rather a symptom that may be associated with various forms of disease and may vary in pathogenesis. The clinical picture depends upon the localisation of the vasculitis. Toxic agents and various viruses may be directly responsible for the vascular lesions. In addition, genetic, autoimmune and allergic factors may be implicated. The immunological pathogenesis is illustrated with reference to the serum sickness model.

Animals↗
PubMed1987

Hematomas in the thymus in dogs.

Twenty dogs with a hematoma of the thymus are described. In four dogs the cause of the hematoma was a ruptured dissecting aneurysm of the aorta and in three cases the dogs had been hit by cars. In seven dogs the necks were overstretched by different factors. One dog was hit by a stone. In two dogs no anamnestic data were available, and in the last three cases, according to owner's statements, no trauma had occurred before the first signs. Thymic hemorrhages in the dog should not be considered to be a circumscribed pathogenetic entity. Indications are offered that trauma, or even commonly occurring microtrauma, can be involved in the pathogenesis of the hematomas in the thymus.

Animals↗