Evidence for a compensatory increase in synthesis of brush border enzymes in the jejunum of Irish Setters with gluten-sensitive enteropathy.

OBJECTIVE: To determine whether biosynthesis of aminopeptidase N (ApN), alkaline phosphatase (AP), and total microvillus membrane protein is altered in Irish Setters with gluten-sensitive enteropathy (GSE). ANIMALS: A litter of 6 Irish Setters with GSE and 3 healthy Greyhounds. PROCEDURES: Explants obtained from affected dogs at 4 and 12 months were maintained in vitro and were compared with material from healthy control dogs. Biosynthesis of ApN and AP was monitored by incorporation of [35S]methionine and immunoprecipitation of these enzymes. RESULTS: Jejunal explants from affected Irish Setters had significantly higher rates of biosynthesis of total protein, microvillus membrane protein, AP, and ApN, compared with control tissue. Two forms of ApN with apparent molecular mass of 155 and 135 kd and 4 forms of AP with apparent molecular mass of 210 to 260, 150, 130, and 105 kd were identified in total membrane fractions from control and affected dogs. CONCLUSIONS: Reduced activities of ApN and AP in dogs with GSE are not attributable to decreased synthesis of these proteins and document enhanced synthesis of microvillar membrane proteins, which may be a compensatory response to enterocyte damage. The 150-kd form of AP was most prominent in tissue from the most affected dogs, probably representing an early form of this enzyme. In contrast, the 105-kd form was most intense in tissue from controls and less intense in tissue of affected dogs.

Characterization of intestinal morphologic, biochemical, and ultrastructural features in gluten-sensitive Irish Setters during controlled oral gluten challenge exposure after weaning.

OBJECTIVE: To characterize histologic, biochemical, and ultrastructural changes in the intestine of Irish Setters susceptible to gluten-sensitive enteropathy (GSE) during controlled oral challenge exposure with gluten after weaning. ANIMALS: Six gluten-sensitive and 12 healthy Irish Setters and 3 healthy Greyhounds. PROCEDURE: Jejunal biopsy specimens were taken at 4 and 12 months of age from the 6 gluten-sensitive Irish Setters, which had been reared on a gluten-free diet to which a controlled dose of gluten (0.5 g/kg of body weight/d) was added. Control specimens were obtained at 4 (n = 5) and 12 (7) months of age from the healthy Irish Setters, which had been fed a conventional gluten-containing diet, and at 4 months of age from the healthy Greyhounds fed the controlled dose of gluten. The specimens were subjected to histologic and ultrastructural examinations and assay of brush border enzymes. RESULTS: Gluten-sensitive Irish Setters developed abnormalities characteristic of GSE at 4 months. Abnormalities were comparable to changes not seen previously until 12 months in dogs with GSE fed a conventional gluten-containing diet. In addition, microvilli were stunted and irregular, and a few were vesiculated and reduced in number; the glycocalyx was reduced or absent. By 12 months of age, there was improvement in morphologic and biochemical parameters, indicating partial recovery despite continued exposure to gluten. CONCLUSIONS: Relative early onset of intestinal damage, compared with that previously reported, and subsequent partial recovery suggestive of oral tolerance to gluten may be attributable to oral administration of gluten as a purified extract rather than in dietary cereal, but alternative explanations include differences in environment or genetic susceptibility to gluten.

Intestinal permeability of Irish setter puppies challenged with a controlled oral dose of gluten.

A combined test of intestinal permeability using lactulose (L) and rhamnose (R), and absorptive function using xylose (X) and 3-O-methylglucose (G), was carried out at four, six, eight and 16 weeks of age in 22 healthy control and six gluten-sensitive Irish setter (IS) dogs fed a diet containing a controlled dose of gluten from weaning. Comparisons were made with two groups of 12 healthy control dogs of breeds other than IS, one fed the same diet as the setters and the other fed a gluten-free diet. Gluten-sensitive IS showed a rise in permeability (mean [SEM] urinary L/R) from 0.23 (0.07) at four weeks to 0.39 (0.05) at eight weeks, remaining at 0.36 (0.04) at 16 weeks. These results were significantly higher in gluten-sensitive than control IS at six, eight and 16 weeks, compatible with jejunal biopsy lesions characteristic of gluten-sensitive enteropathy demonstrated in affected dogs at 16 weeks. Urinary L/R ratios of control dogs of breeds other than IS peaked at six weeks 0.27 (0.02), and were significantly higher than those of control IS at six and eight weeks, demonstrating differences in permeability between Irish setter dogs and other breeds at this age. There were no significant differences in urinary X/G ratios at six, eight and 16 weeks of age between any of the groups of dogs challenged with gluten. Urinary L/R and X/G ratios were similar in the control dogs of breeds other than IS fed gluten-containing and gluten-free diets. These findings indicate that intestinal permeability testing of puppies during controlled oral gluten challenge provides a practical screening test for gluten sensitivity in Irish setter dogs at an early age.

A blood test for intestinal permeability and function: a new tool for the diagnosis of chronic intestinal disease in dogs.

We demonstrate that rhamnose, 3-O-methyl-D-glucose, D-xylose and lactulose may be quantified accurately in blood by HPLC and pulsed amperometric detection, thus enabling studies of intestinal permeability and function to be carried out using plasma samples. Prior to HPLC, the endogenous glucose was enzymatically modified to gluconic acid and the protein precipitated. The precision of the quantification of the sugars in plasma (CV: 2.2-5.7%; 8.7-10.6% at very low concentrations) compared well with the quantification in urine. The results for groups of 8 dogs with small intestinal bacterial overgrowth and 12 dogs with inflammatory bowel disease were shown to be significantly different from a group of 20 normal control dogs (P < 0.001), demonstrating the test's value as a diagnostic tool. The normal ranges in blood 2 h post oral administration were determined to be 0.05-0.17 for the lactulose/rhamnose ratio and 0.45-0.65 for the xylose/3-O-methylglucose ratio. This method may be employed advantageously when the collection of urine in intestinal permeability and function tests is difficult.

Gluten-sensitive enteropathy in Irish setter dogs: characterisation of jejunal microvillar membrane proteins by two-dimensional electrophoresis.

This study investigated whether gluten-sensitive enteropathy (GSE) in Irish setter dogs was associated with underlying structural abnormalities of microvillar membrane proteins. Jejunal biopsies taken from eight-month-old GSE-affected dogs reared on a normal, gluten-containing diet exhibited partial villous atrophy and contained more intra-epithelial lymphocytes than controls. The morphological abnormalities were reversed by feeding a gluten-free diet for five months and the changes were accompanied by an increase in the mucosal activity of the microvillar hydrolases, particularly aminopeptidase N and dipeptidyl aminopeptidase IV, which reverted to pre-treatment levels after a gluten challenge. Two-dimensional electrophoresis of microvillar membrane proteins isolated from GSE-affected dogs revealed an essentially normal protein map that was comparable to controls. The exception was an intense 85 kDa protein spot that diminished when the affected dogs were fed a gluten-free diet and re-intensified after a gluten challenge.

Canine major histocompatibility complex genes DQA and DQB in Irish setter dogs.

Information about genetic variation within the canine major histocompatibility complex (MHC) class II genes is limited. In common with most other vertebrate species the canine MHC, or DLA, includes genes which are homologous to human DR, DQ, and DP. Recently, at least one functional DLA DQ gene-pair has been characterized, but so far systematic screening efforts have been lacking. In the present study, we sequenced both cDNA and genomic clones derived from DLA DQ genes of Irish setter dogs. This breed was of interest, since it shows a high prevalence of gluten sensitive enteropathy (GSE), which may be a useful animal model for celiac disease (CD) of man. Interestingly, few of the alleles found in Irish setters were identical to those previously detected in other breeds. Three novel DLA DQA and four novel DLA DQB alleles were discovered in 19 unrelated dogs. Strong association between certain HLA DQ alleles and CD of man prompted us to screen the DQ alleles of members of a family of gluten-sensitive Irish setter dogs. No haplotypes or alleles were shared by all affected dogs, but one frequent haplotype in this family was also detected in an unrelated gluten-sensitive Irish setter; this haplotype was absent in the healthy dogs. This observation warrants further investigation by screening the DQ alleles of a large population of unrelated gluten-sensitive Irish setters.

[Principles for thrombosis prevention at surgery departments in Denmark]. / Principper for troboseprofylakse på kirurgiske afdelinger i Danmark.

In 1995 all surgical departments in Denmark were asked to reply to a questionnaire about their use of postoperative thromboprophylaxis. Response rate was 95%. Ninety-two percent of the departments performing major surgery routinely used prophylaxis, in 84% of these according to prior written instructions, but still only 36% use prophylaxis in emergency surgery. The indications and methods used are in accordance with recommendations in the literature. The use of aspirin as prophylaxis against venous thromboembolism should be avoided, and the use of prophylaxis in emergency surgery should be improved. The most commonly used method was low molecular weight heparin (82%) often in combination with graduated elastic stockings. There is no longer any doubt about the need for prophylaxis. The tasks of the future are to identify the risk groups and establish the duration of prophylaxis.

Reference range and repeatability of a combined intestinal permeability and function test in clinically healthy Irish setter dogs.

A reference range was determined for a combined test of differential sugar permeability, using lactulose (L) and rhamnose (R), and intestinal function, using D-xylulose (X) and 3-O-methylglucose (G), in clinically healthy adult Irish setter dogs. Urinary L/R ratios in 48 Irish setters from one to 12 years old varied from 0.03 to 0.18, with a mean (SEM) of 0.10 (0.01); X/G ratios varied from 0.46 to 0.81, with a mean (SEM) of 0.59 (0.01). There were no significant differences between L/R or X/G ratios of dogs of different sex (P > 0.2) or age (P > 0.5), using analysis of covariance. Lactulose/rhamnose ratios of > or = 0.18 and X/G ratios > or = 0.43 were considered normal, defined by the respective mean +/- 2SD. Repeatability was established by performing three permeability and function tests at monthly intervals in twelve of the dogs. Analysis of repeated L/R and X/G ratios by means of linear models procedure revealed no significant differences between measurements made on successive occasions (P > 0.15), confirming the repeatability of this test.

An aminopeptidase N deficiency in dog small intestine.

This study has identified a naturally occurring, specific deficiency of a brush border aminopeptidase N (ApN) in the small intestines of five clinically healthy dogs. ApN activity in mucosal homogenates of dog small intestine was reduced significantly in deficient animals (13.4 (1.1) nmol min-1 mg-1 protein, n = 5, P < 0.002) compared to healthy control dogs (95.1 (6.7), n = 22). Alkaline phosphatase, gamma-glutamyl transferase, zinc-resistant alpha-glucosidase, maltase, sucrase and lactase in the ApN deficient dogs exhibited comparable activities to those in the control dogs. Microvillar membranes were analysed by one- and two-dimensional electrophoresis. ApN was represented by a single 145kDa band in all control dogs, identified by immunoblotting and immunoprecipitation. Protein maps from deficient dogs were normal apart from the virtual absence of an ApN spot and there were no apparent abnormalities in the glycosylation of microvillar proteins. The findings suggest that intestinal ApN deficiency in these dogs is a primary lesion involving diminished expression of an otherwise normal enzyme protein.

[Activated protein C resistance as the cause of recurrent mesenteric venous thrombosis]. / Aktiveret protein C-resistens som årsag til recidiverende mesenterialvenetrombose.

We describe a case of a 72-year-old woman, identified as resistant to activated protein C and with attacks of abdominal pain after mesenteric venous thrombosis ten years ago, now successfully treated with anticoagulant therapy. We point out the need for screening for coagulation disorders among patients with venous thrombotic events.

Intestinal permeability and function in dogs with small intestinal bacterial overgrowth.

Small intestinal bacterial overgrowth (SIBO) has been reported to occur commonly in dogs with signs of chronic intestinal disease. There are usually few intestinal histological changes, and it is uncertain to what extent bacteria cause mucosal damage. The aim of this study was to apply a differential sugar absorption test for intestinal permeability and function to the objective assessment of intestinal damage in dogs with SIBO. Studies were performed on 63 dogs with signs of chronic small and, or, large bowel disease, in which SIBO (greater than 10(5) total or greater than 10(4) anaerobic colony forming units/ml) was diagnosed by quantitative culture of duodenal juice obtained endoscopically. None of the dogs had evidence of intestinal pathogens, parasites, systemic disease or pancreatic insufficiency. differential sugar absorption was performed by determining the ratios of urinary recoveries of lactulose/rhamnose (L/R ratio, which reflects permeability) and D-xylose/3-O-methylglucose (X/G ratio, which reflects intestinal absorptive function) following oral administration. Dogs with SIBO comprised 28 different breeds, including 13 German shepherd dogs. SIBO was aerobic in 18/63 dogs (29 per cent), and anaerobic in 45/63 (71 per cent). Histological examination of duodenal biopsies showed no abnormalities in 75 per cent, and mild to moderate lymphocytic infiltrates in 25 per cent of the dogs. The L/R ratio was increased (greater than 0.12) in 52 per cent, and the X/G ratio reduced (less than 0.60) in 33 per cent of the dogs. Differential sugar absorption was repeated in 11 dogs after their four weeks of oral antibiotic therapy. The L/R ratio declined in all 11 dogs (mean +/- SD pre: 0.24 +/- 0.14; post: 0.16 +/- 0.11; P < 0.05), but changes in the X/G ratio were more variable. These findings show that SIBO is commonly associated with mucosal damage not detected on histological examination of intestinal biopsies, and that changes in intestinal permeability following oral antibiotics may be used to monitor response to treatment.

Growth and propagation of normal rat intestinal epithelial cells.

A combination of mild proteolytic digestion and selective growth stimulation has been used to isolate and propagate adult rat intestinal epithelial cells with a finite life span. Growth of these cells on a variety of matrices and on mesenchymal cells has resulted in the expression of brush border enzymes including sucrase-isomaltase, aminopeptidase N, and alkaline phosphatase. Examination of the cells at the electron microscopic level has revealed that although these cells express key brush border enzymes, they do not have a fully formed brush border. These findings suggest that the expression of brush border enzymes and structural proteins represent distinct stages of enterocyte differentiation that are under separate transcriptional and temporal control.

Subcellular biochemical changes during the development of the small intestine of pony foals.

To examine the postnatal development of equine small intestine, biopsy specimens of jejunal mucosa from 8 ponies, between 6 and 28 weeks old, were subjected to analytical subcellular fractionation and assay of organelle marker enzymes. Fractionation revealed a reduction in the particulate brush border component of beta-galactosidase (lactase) activity between 6 and 28 weeks, and a corresponding increase in soluble activity, although the reduction in mean specific activity was not significant. There also was a decrease in the proportion of brush border to soluble aminopeptidase N activity, a relative loss of brush border gamma-glutamyltransferase activity, and a considerable decrease in the specific activity of alkaline phosphatase throughout the gradient fractions. In contrast, there were marked increases in activities of alpha-glucosidase (maltase) and sucrase in the older ponies, accompanied by considerable changes in the intracellular distribution of particulate alpha-glucosidase activity, which was predominantly associated with endoplasmic reticulum at 6 weeks, whereas the large increase in activity observed by 28 weeks was clearly associated with the brush border. The modal density of brush borders also increased with age, suggestive of an increase in the glycoprotein-to-lipid ratio of the microvillar membrane. In contrast to these brush border changes, there was relatively little alteration in the activities or density distributions of marker enzymes for endoplasmic reticulum, basolateral membranes, mitochondria, or lysosomes. These findings indicate that maturation of equine intestinal epithelium during the first few months of life results in major changes in the properties and enzyme composition of enterocyte brush borders.

Intestinal permeability testing in dogs with diet-responsive intestinal disease.

Fifteen dogs with signs of small and, or, large bowel disease that responded clinically to an exclusion diet were studied, using differential sugar absorption as an objective parameter of the mucosal response to the diet. Intestinal permeability and function were assessed by determining the urinary excretion ratios of lactulose/rhamnose and xylose/3-O-methylglucose, respectively, following oral administration of a mixture of these four sugars. Five dogs, all retrievers, were tentatively diagnosed as having dietary hypersensitivity, based upon resolution of clinical signs and normalisation of high intestinal permeability following an exclusion diet and recurrence of signs (in four of five dogs) upon challenge with the original diet. The fifth dog did not become symptomatic when challenged, but intestinal permeability increased. The remaining 10 dogs were diagnosed as having food intolerance, based upon clinical improvement on an exclusion diet, relapse on challenge with their original diet, but lack of improvement in intestinal permeability. These findings suggest that a differential sugar absorption test may be useful to determine the reasons for clinical response to exclusion diets. Demonstration of increased intestinal permeability with subsequent normalisation following an exclusion diet may be useful in the diagnosis of dietary hypersensitivity, while persistent abnormalities in intestinal permeability are suggestive of underlying intestinal disease and food intolerance.

Characterization of microvillar membrane proteins of dog small intestine by two-dimensional electrophoresis.

A method for analysing microgram amounts of microvillar membranes by two-dimensional electrophoresis (protein mapping) is described, and has been used to characterize the microvillar proteins of the small intestine of German shepherd, corgi, and beagle dogs. Detergent-solubilized microvillar membranes were radiolabelled with 14C and separated by isoelectric focussing followed by SDS-PAGE. Proteins were detected fluorographically and glycoproteins by lectin-affinity staining. The microvillar hydrolases alkaline phosphatase and dipeptidyl aminopeptidase IV were identified by active-site labelling and aminopeptidase N by immunoprecipitation. Changes following pancreatic duct diversion were consistent with accumulation of pro-sucrase-isomaltase and diminished expression of the sucrase and isomaltase subunits. Cytoskeletal proteins were concentrated in the core fraction remaining after extraction of microvillar membranes with Triton X-100. There were no consistent differences between dogs of different breed, and the canine protein maps were similar to the human.

Diarrhoea and increased intestinal permeability in laboratory beagles associated with proximal small intestinal bacterial overgrowth.

Repeated episodes of diarrhoea were seen in 4 laboratory beagles after experimental renal surgery and feeding a modified diet. Small intestinal bacterial overgrowth (SIBO) was suspected by exclusion of other causes and measurement of plasma folate. SIBO was confirmed by quantitative duodenal bacteriology. Beagles with SIBO can show no clinical signs, experimental stress and dietary change may have been reasons why these 4 beagles exhibited clinical signs with SIBO. Despite normal gut histology an increase in gut permeability was found using sugar absorption tests. This increased permeability had the potential to cause variations in drug absorption during experimental studies.

A novel HPLC method for the simultaneous quantification of monosaccharides and disaccharides used in tests of intestinal function and permeability.

The quantification of monosaccharides and disaccharides used as probes in intestinal function and permeability tests can be technically demanding, detracting from the value of this approach to the indirect assessment of intestinal damage. In this study, a procedure is described for the simultaneous quantification of rhamnose, lactulose, 3-O-methyl-D-glucose and xylose in urine by HPLC using an anion exchange column with pulsed amperometric detection. This method is relatively fast and simple to perform, requiring no pre-treatment of urine samples or post-column derivatization. Accuracy and precision of determinations are illustrated by analytical recoveries (mean percentage +/- S.D., CV., n = 30) for multiple batch analyses of a diluted urine sample containing 20 mg/l of rhamnose (100 +/- 6.8, 6.2%), lactulose (100 +/- 6.1, 5.5%), 3-O-methyl-D-glucose (98 +/- 5.9, 5.5%) and xylose (104 +/- 7.1, 6.5%). Linearity of standard curves indicated that the lower limit for accurate quantification was 0.1 mg/l for all four sugars. Urinary recoveries following oral administration of these sugars to control dogs were determined as a baseline for the investigation of intestinal damage in this species and comparison of chromatograms illustrated enhanced permeability in dogs with gluten-sensitive enteropathy.

Biochemical changes in the jejunal mucosa of dogs with exocrine pancreatic insufficiency following pancreatic duct ligation.

The effects of exocrine pancreatic insufficiency on the small intestinal mucosa were examined in dogs following pancreatic duct ligation. There were no significant changes either in villus architecture or enterocyte height after duct ligation, but numbers of bacteria in duodenal juice increased then subsequently decreased following treatment with exogenous pancreatic enzymes. Pancreatic insufficiency resulted in a considerable increase in the proportion of microvillar membrane proteins of molecular mass over 200 kDa from 3.3 +/- 4 per cent (mean +/- SEM) to 13.6 +/- 7.2 per cent, and this decreased to 6.9 +/- 5.2 per cent following pancreatic enzyme supplementation. However, anticipated increases in activities of maltase and sucrase were not observed following duct ligation, and there was a reduction in lactase activity which was reversed by pancreatic supplementation. Activities of marker enzymes for the other subcellular organelles showed relatively minor or no changes throughout the study. These findings are consistent with a specific role for pancreatic enzymes in the post-translational processing of intestinal microvillar membrane proteins, and suggest that reduced degradation of brush border proteins in the absence of pancreatic secretions may be masked by quantitative and qualitative changes in the intestinal microflora.

Investigation of the physical properties of dog intestinal microvillar membrane proteins by polyacrylamide gel electrophoresis: a comparison between normal dogs and dogs with exocrine pancreatic insufficiency.

Procedures have been validated for the investigation of the physical properties of canine microvillar membrane proteins by SDS-polyacrylamide gel electrophoresis. These have been used to examine mucosal samples from eight control dogs and from five dogs with naturally occurring exocrine pancreatic insufficiency (EPI) in order to evaluate the potential role of the pancreas in the normal turnover of microvillar membrane proteins in the dog. Gel scanning showed that the proportion of total membrane protein in bands corresponding to a molecular mass greater than 200 kDa was up to 20-times higher in dogs with EPI than in control dogs. In particular, a band of apparent molecular mass 218 kDa represented between 8 and 28% of membrane protein in all affected dogs, compared with only 0.5 to 1.8% in controls, and is most likely to contain single chains of both pro-maltase-glucoamylase and pro-sucrase-isomaltase. Incubation of microvillar membranes in vitro with either trypsin or canine pancreatic juice resulted in degradation of this high molecular mass band and a corresponding increase in the amount of protein in three bands representing molecular masses of 150, 133 and 106 kDa. In samples from control dogs aminopeptidase N was identified in the 133 kDa band by Western blotting and incubation with monospecific antiserum. These findings suggest that pancreatic enzymes play a major role in the normal post-translational processing of intestinal microvillar membrane proteins in the dog.

A comparison of metoclopramide vs. droperidol/phenobarbital for emesis induced by chemotherapy.

Chemotherapy-induced nausea and vomiting cause morbidity and poor compliance among patients receiving intensive cancer chemotherapy. High-dose antiemetic regimens, while effective, add significantly to the cost of treatment. This study compares the efficacy and cost of high-dose metoclopramide with a combination of phenobarbital and droperidol. All patients treated were naive to prior chemotherapy, and all patients received treatment regimens containing cisplatinum. Both antiemetic regimens proved equally efficacious in suppressing emesis, but the phenobarbital/droperidol combination achieved a 100-fold decrease in cost.