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Biomedical subjects

M Staun

Publications and source records attributed to M Staun.

51 records · Page 3Linked to original sources
PubMed1990

Calcium absorption and bone mineral content in patients subjected to ileal bypass because of familial hypercholesterolaemia.

Calcium absorption and bone mineral content were studied prospectively in 30 patients with familial hypercholesterolaemia subjected to partial ileal bypass surgery. One-third of the patients were followed up for 10 years after the operation. Six months postoperatively calcium absorption decreased significantly, from a median of 16% to 13%. The effect persisted up to 5 years of follow-up study. Ten years after the operation the absorption of calcium (median, 14.5%) was not significantly different from the preoperative calcium absorption (median, 16%). Bone mineral content, measured in 76% of the patients, was retained in all patients studied. A significant correlation was present between calcium absorption and urinary calcium. The reduction in calcium absorption did not correlate with increases in faecal fat. Other long-term side effects were persistent diarrhoea and moderate steatorrhoea. A significant weight loss was slowly regained in most patients. An increase of renal oxalate excretion was only small and transient in most patients. The study shows that bypass of the terminal 200 cm of ileum for familial hypercholesterolaemia causes moderate diarrhoea and steatorrhoea in most patients but only a slight reduction of intestinal calcium absorption and apparently no risk of bone demineralization. A benefit of a postoperative calcium and vitamin D supply cannot be excluded.

Adult↗
PubMed1989

Immunomicroscopic localization of the 10,000 molecular weight calcium-binding protein in the human enterocyte.

The cellular localization of the 10,000 molecular weight calcium-binding protein (CaBP or Calbindin-D) in the small intestinal epithelium of man was investigated by immunofluorescence and immunoelectron microscopy (immunogold staining). Indirect immunofluorescence on frozen sections showed intracellular staining in the enterocyte. The fluorescence was evenly distributed and no significant differences were observed between crypt and villus cells. No staining was found in goblet cells or in the submucosa. Correspondingly, immunogold labeled antibodies were scattered over the cytoplasm of the enterocyte. The terminal region appeared to be the most intensely decorated and the brush border region showed labeling above the background level. No labeling was associated with intracellular membranes or the basolateral membrane.

Calcium-Binding Proteins↗
PubMed1988

Calcium-binding protein in human duodenal biopsies.

Intestinal calcium-binding protein (CaBP) (molecular weight 10,000) was measured by a specific enzyme-linked immunoadsorbent assay in duodenal biopsies of 94 patients (aged 20-89 years). The patients were examined for complaints of upper abdominal dyspepsia, but no significant pathology was found by gastroduodenoscopy. The median amount of CaBP in duodenal biopsies was 6.0 micrograms/mg of cytosolic protein with a coefficient of variation of 0.6. No change in the amount of CaBP per mg of cytosolic protein was observed with age. A significant correlation (P less than 0.001) was found between the concentration of CaBP and s-1,25-dihydroxyvitamin D (1,25(OH)2D). The amount of CaBP per mg of cytosolic protein did not correlate with immunoreactive parathyroid hormone in serum, and no relation between CaBP and the specific activity of alkaline phosphatase of the mucosal biopsies was found. The results of the present study show a wide variation in the amount of the 10 kDa CaBP in duodenal biopsies of humans and no change with age. Further, a correlation between s-1,25(OH)2D and CaBP was found.

Adult↗
PubMed1988

Measurement of the 10,000-molecular weight calcium-binding protein in small-intestinal biopsy specimens from patients with malabsorption syndromes.

Calcium-binding protein (CaBP) (molecular weight, 10,000) was measured in small-intestinal biopsy specimens from 36 patients with malabsorption syndromes: short-bowel syndrome (n = 13), untreated coeliac disease (n = 4), coeliac disease in remission (n = 7), patients with intestinal bypass owing to morbid obesity (n = 5), and in patients with chronic diarrhoea of unknown cause (n = 7). Twelve patients with no signs of malabsorption who had the irritable bowel syndrome were used as controls. Patients with small-bowel resections showed reduced concentrations of CaBP (p less than 0.01) and low intestinal calcium absorption (p less than 0.05). Small amounts of CaBP were found in intestinal specimens from patients with coeliac disease in remission (p less than 0.01), and CaBP was almost undetectable in patients with a newly diagnosed coeliac disease and avillous jejunal biopsy findings (p less than 0.001). Patients with chronic diarrhoea and patients with an intestinal bypass had CaBP concentrations comparable to those of the control group. A direct correlation was found between CaBP and the fractional calcium absorption in all patients (p less than 0.05). CaBP may therefore be considered an indicator of the efficiency of the small intestine to absorb calcium.

Adult↗
PubMed1987

The crypt-villus distribution of the 10,000 Mr intestinal calcium binding protein in human jejunum.

The amount of small intestinal calcium-binding protein was studied in biopsies of human jejunum sectioned perpendicular to the long axis of the villi. Brush-border aminopeptidase N activity was measured to distinguish undifferentiated crypt cells from mature villus cells. The amount of calcium-binding protein as measured by enzyme-linked immunoadsorbent assay was highest at the villus tip and gradually decreased to near zero values in the crypt. The distribution of calcium-binding protein observed is parallel to that found in vitamin D repleted rats. The present study indicates that the mature enterocyte in man is fully committed to express calcium-binding protein in accordance with the view that these cells are considered the most active in the calcium absorptive mechanism.

Adult↗
PubMed1987

Distribution of the 10,000 molecular weight calcium binding protein along the small and large intestine of man.

The distribution of the 10,000 molecular weight calcium binding protein along the human small and large intestine was studied using an enzyme linked immunoadsorbent assay. Small intestinal mucosal samples were obtained from the duodenal bulb, the second and third part of the duodenum and at about 50 cm intervals from jejunum and ileum of five whole small intestines of necro-kidney donors. Mucosal samples of caecum, colon ascendens, and transversum were also investigated. The amount of calcium binding protein per milligram of cytosolic protein increased throughout duodenum to reach the maximum in the proximal segment of jejunum and then declined steadily to nearly undetectable levels in ileum. In the colon no 10,000 molecular weight CaBP was detectable. The distribution of CaBP along the small and large intestine of man is thus parallel to the efficiency of the active calcium absorption of human intestine.

Adolescent↗
PubMed1986

Enzyme-linked immunoadsorbent assay (ELISA) for calcium-binding protein of human small intestine. A quantitative method for measuring calcium-binding protein in small intestinal biopsies.

A method for measuring calcium-binding protein (CaBP) in small intestinal biopsies of the human is reported. The assay is performed as a competitive enzyme-linked immunoadsorbent assay (ELISA). Pure CaBP and a cytosol fraction of human jejunum generate competitive displacement curves running in parallel thus demonstrating the antigen specificity of the assay. Non-specific displacement of anti-CaBP antibodies from the solid phase CaBP is negligible as demonstrated by the inability of cytosolic proteins of rat small intestine to produce a detectable response in the assay. The method has a detection limit of 3 ng CaBP (applied in 150 microliter) and a coefficient of variation of 9.8%. The ELISA method is applicable in the study of the role of CaBP in clinical disorders of the small bowel.

Animals↗
PubMed1986

Calcium-binding protein from human small intestine. Purification and characterization of a 10,000 molecular weight protein.

A calcium-binding protein (CaBP) was purified from human small intestinal mucosa by ammonium sulphate fractionation, gel filtration and chromatofocusing. Antibodies against CaBP were raised in rabbits and CaBP was then isolated from human intestinal cytosol by a one-step immunoadsorbent procedure. In polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate CaBP migrated as a single band corresponding to a molecular weight of 10,000. The calcium-binding ability of CaBP was demonstrated by increased electrophoretic mobility of CaBP in the presence of EDTA as demonstrated by immunoblotting of agarose gels. CaBP antibody showed no cross reaction with cytosolic proteins of duodenum from rat or pig. The present study suggests that molecular properties and distribution of human intestinal CaBP is comparable to those of intestinal CaBP detected in lower mammalian species.

Adolescent↗
PubMed1984

Ca2+-binding protein from human kidney. Purification and properties.

A Ca2+-binding protein (CaBP) from human kidney was purified by two different procedures. The first involved heat-precipitation of a kidney cytosol fraction followed by gel filtration and chromatofocusing. This resulted in a 200-fold increase in the specific Ca2+-binding activity with a yield of 10%. A specific antibody was raised against the purified CaBP, as demonstrated by one precipitate in crossed immunoelectrophoresis of a kidney cytosol fraction. The antibody was coupled to Sepharose 4B and CaBP was then purified by immunoadsorbent chromatography. Applying this technique, a 500-fold purification of CaBP with a yield of 50% was obtained. Both preparations appeared homogeneous in crossed immunoelectrophoresis against a polyvalent antiserum and migrated as a single band corresponding to a mol.wt. of 26000 on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. In gel filtration under non-denaturing conditions CaBP was eluted corresponding to a mol.wt. of 28000. The association constant for the high-affinity Ca2+-binding sites of CaBP was estimated by gel filtration to be 0.1 X 10(6)M-1, and the protein displayed Ca2+-dependent electrophoretic mobility, with more rapid anodic migration in the presence of EDTA. The protein eluted at a position corresponding to a pI of 4.5 in chromatofocusing. Immunochemical experiments with the specific antibody showed no cross-reaction between renal and intestinal CaBP.

Binding Sites↗
PubMed1979

Comparison of two pig intestinal brush border peptidases with the corresponding renal enzymes.

Intestinal dipeptidyl peptidase IV and gamma-glutamyltransferase were compared to the corresponding kidney enzymes with respect to immunological and electrophoretic properties. The influences of selected effectors on the two enzymes were also studied. The two kidney peptidases exhibited the reaction of total identity with the corresponding intestinal enzymes in immunodiffusion. Furthermore, the intestinal dipeptidyl peptidase IV and gamma-glutamyl transferase showed the same inhibition patterns as the corresponding kidney enzymes and the acceptor specificity of the intestinal gamma-glutamyl-transferase was found to be identical to that of the kidney enzyme. The electrophoretic mobilities of dipeptidyl peptidase IV from the two organs differed greatly. The difference was almost abolished by treatment with neuraminidase, suggesting that the variation in mobility was due to different contents of sialic acid. It is suggested that the intestinal brush border peptidases, dipeptidyl peptidase IV and gamma-glutamyltransferase, are closely related to the corresponding enzymes obtained from the kidney.

Animals↗
PubMed1977

Intestinal brush border peptidases.

A brush-border-specific antiserum was raised in rabbits, with Triton X-100-solubilized brush border proteins from pig intestine being used as antigens. The antiserum was used in immunoelectrophoretic studies of brush border proteins solubilized with Triton X-100. Five immunoprecipitates were obtained which corresponded to microsomal aminopeptidase (EC 3.4.11.2), asparate aminopeptidase (EC 3.4.11.7), lactase (beta-galactosidase, EC 3.2.1.23), maltase (exo-1,4-alpha-glucosidase, EC 3.2.1.3) and sucrase-isomaltase (sucrose alpha-glucohydrolase, EC 3.2.1.48). A faint immunoprecipitate was also found for the glycylprolyl dipeptidyl peptidase (EC 3.4.14.-). The brush border proteins were solubilized on a large scale from a brush border membrane preparation by the use of Triton X-100; the peptidases obtained were homogeneous in size and had hydrophobic properties. By chromatography on columns of concanavalin A-Sepharose, hydroxyapatite, Ultrogel AcA 34, DEAE-cellulose and immunosorbent, gamma-glutamyl transpeptidase (gamma-glutamyl transferase, EC 2.3.2.2) and microsomal aminopeptidase were each isolated in separate fractions. Glycylprolyl dipeptidyl peptidase and asparate aminopeptidase were obtained in another fraction. Immunoelectrophoretic, inhibitor and chromatographic studies showed that the intestinal brush border peptidases are similar to the corresponding particulate peptidases obtained from other organs.

Amino Acids↗
PubMedDate not supplied

Selenoprotein P in patients on home parenteral nutrition.

BACKGROUND: The purpose of this study was to evaluate the use of selenoprotein P as an indicator of selenium status in patients receiving home parenteral nutrition. METHODS: Adult patients (n = 38) who had been on parenteral nutrition with no addition of selenium for 3 to 216 months were included in the study. Plasma samples were analyzed for selenium, selenoprotein P, and extracellular glutathione peroxidase (eGSHPx) using fluorimetry and newly developed radioimmunoassays. RESULTS: The mean plasma (+/- SD) eGSHPx and selenoprotein P in the patients were 1.9 +/- 1.2 mg/L and 0.7 +/- 0.4 arbitrary units, respectively, which corresponds to about 50% of the concentration measured in the plasma of the reference subjects (4.0 +/- 1.0 mg/L and 1.50 +/- 0.17 arbitrary units). The mean plasma selenium concentration was 0.5 +/- 0.4 mumol/L, which was approximately half of the concentration measured in the healthy subjects (1.1 +/- 0.2 mumol/L). Thirty-four (89%) and 20 (53%) patients, respectively, had selenoprotein P and eGSHPx values lower than mean - 2 SD of the reference material. The lowest values observed for selenoprotein P and eGSHPx were 3% and 2% of the reference mean. Selenoprotein P levels correlated significantly to eGSHPx (p = 0.88, p < .0001) and plasma selenium (p = 0.91, p < .0001). CONCLUSIONS: The positive correlations between selenoprotein P and eGSHPX and plasma selenium indicates that selenoprotein P may be used as a marker of selenium status in selenium-depleted patients.

Aged↗
PubMedDate not supplied

The metabolism of [75Se]selenite in patients with short bowel syndrome.

BACKGROUND: Patients on home parenteral nutrition (HPN) require significantly higher amounts of selenium compared with controls. The purpose of the present study was to investigate if selenium deficiency of patients with short bowel syndrome is caused by selenium malabsorption or by excessive intestinal or renal loss. METHODS: The metabolism of [75Se]selenite was investigated in eight selenium-depleted short bowel patients on HPN and in six control subjects. The isotope was given orally, and in a subsequent study as bolus injection or as 12-hour IV infusion. RESULTS: The fractional intestinal absorption of selenium was significantly reduced in the patients (2% to 58%, median 20%) when compared with the reference group (79% to 91%, median 82%) (p < .001). Within the group of patients we found a positive significant correlation between fractional selenium absorption and the length of the remaining small intestine (r = 0.95, p < .05). After parenteral [75Se]selenite administration, the patients showed a significantly higher fecal loss and a significantly reduced urinary excretion of 75Se when compared with the controls. Bolus injection vs 12-hour infusion of [75Se]selenite did not affect the cumulative fecal or urinary 75Se excretion in the HPN patients. CONCLUSIONS: Reduced intestinal selenium absorption is probably the most important cause of the selenium deficiency reported in patients with short bowel syndrome, but increased endogenous intestinal selenium loss and low selenium intake may also contribute. Despite the renal counterregulation, which results in a low urinary selenium excretion, HPN patients need a supply of selenium with their parenteral nutrition.

Adult↗