PubMed Health⌕ Search

Biomedical subjects

K J Andersen

Publications and source records attributed to K J Andersen.

At least 73 records · Page 4Linked to original sources
PubMed1977

Interaction of conjugated bile acids and detergents with a radiosorbent assay of vitamin B-12.

The effect of conjugated bile acids and detergents on the radiosorbent technique for the determination of vitamin B-12 activity is reported. It is shown that whereas the non-ionic detergent Triton X-100 has no effect on the vitamin B-12-radiosorbent assay, the addition of ionic detergents (e.g. glycocholic acid, taurocholic acid or sodium laurly sulfate) results in a falsely elevated vitamin B-12 activity presumably due to the disruption of the binding of vitamin B-12 to the intrinsic factor-Sephadex complex. This effect may be of importance not only to the radiosorbent assaying of vitamin B-12, but to the in vivo intestinal absorption of vitamin B-12 as well.

Bile Acids and Salts↗
PubMed1977

Membrane filtration in microscopical examination of urinary sediment.

Microscopical examination of the urinary sediment has been performed after membrane filtration and after routine centrifugation, and the results were compared. Various quantities of urine were filtered through a membrane with pore size of 3 micrometer, stained with Shorr stain and made translucent with xylol. All granular and cellular casts were counted on a trimmed membrane, 15 X 20 mm. The routine centrifugation was carried out on 10 ml urine at 1500 rpm for 3 min. Among 11 patients with glomerulonephrits and recurrent hematuria, casts were found in 9 after filtration but in only 2 after routine centrifugation. Casts were detected by the filter method in the urine after angiography of the kidneys in 8 of 12 patients, after centrifugation in only one of them. No casts were found in 6 patients with hematuria due to urological disorders and in 21 healthy persons. The diagnostic sensitivity of microscopical examination of urine was greatly increased by the filter method. This may be due to larger amount of urine examined by the filter method, but an additional cause may be that routine centrifugation destroys red cell casts.

Adolescent↗
PubMed1977

The mechanism of lincomycin-induced diarrhoea.

Metabolic studies were performed before and seven days after treating rats orally with lincomycin. Following the treatment the mean faecal weight increased from 302.2 g/72 hr +/- 3.8 (S.D.) to 65.5 +/- 8.2. The faecal fat excretion was unchanged, and the weight increase was mainly due to increased water content. To find whether the watery diarrhoea was due to bile acid malabsorption, the absorption rate of [14C]-taurocholic acid was measured in untreated rats and rats treated with lincomycin using an in vivo perfusion technique. There was no significant difference in bile acid absorption rate measured at three different concentrations of bile acid in the perfusate. Alternative mechanisms of lincomycin-associated diarrhoea are discussed.

Animals↗
PubMed1977

Pancreatic extract and the intestinal uptake of vitamin B12. II. Inhibitory effect of trypsin and trypsinogen.

Pancreatic extract (PE) contained small-molecular, thermo-stable as well as macro-molecular, thermo-labile factors capable of reducing the uptake of 57CoB12 bound to rat intrinsic factor by perfused rat intestinal segments (p less than 0.01 and p less than 0.01). Neither non-radioactive vitamin B12 nor non-pacreatic protein reduced the 57CoB12-uptake (p greater than 0.5 and p greater than 0.1) Crystalline trypsin and trypsinogen, but not chymotrypsin, also inhibited the uptake (p less than 0.05, p less than 0.02 and p greater than 0.05). The tryptic inhibition was abolished by soybean trypsin inhibitor (p greater than 0.05).

Animals↗
PubMed1977

Pancreatic extract and the intestinal uptake of vitamin B12. III. Stimulatory effect in the presence of a non-intrinsic factor vitamin B12 binder.

To determine the mechanism by which pancreatic extract (PE) corrects the malabsorption of vitamin B12 in chronic pancreatic insufficiency (CPI), the following hypotheses were investigated: Firstly, PE might stimulate the absorption of vitamin B12 by changing the intestinal pH, secondly PE might stimulate the intestinal uptake of unbound vitamin B12, thirdly PE might abolish the inhibitory effect of vitamin B12 binders on the intestinal uptake of vitamin B12 bound to intrinsic factor (IF). PE had no effect on the pH in the small intestine and did not stimulate the uptake of unbound 57CoB12 by perfused rat intestinal segments. Preincubation of 57CoB12-IF with a non-IF B12-binder from human saliva (R-binder) reduced the uptake of 57CoB12 from 18.5 pg per cm intestine +/- 3.4 S.E.M. to 7.8 +/- 1.6 (p less than 0.02). PE abolished this inhibitory effect (p less than 0.05). The results indicate that PE corrects the malabsorption of vitamin B12 in CPI by an effect on non-IF B12- binders.

Animals↗
PubMed1977

Pancreatic extract and the intestinal uptake of vitamin B12. I. Effect on the intestinal epithelium and the vitamin B12-intrinsic factor complex.

Pancreatic extract (PE) reduced the uptake of rat intrinsic factor (IF)-bound 57CoB12 by perfused rat intestinal segments (p is less than 0.02) as well as by isolated rat intestinal brush borders (p is less than 0.01). The inhibition was concentration-dependent. Preincubation of the brush borders with PE recular weight of the 57CoB12-IF complex, as well as the uptake of the complex by isolated intestinal brush borders, was unchanged after prolonged preincubation with PE. PE also inhibited the uptake of glucose by perfused intestinal segments (p is less than 0.01), but the morphology and idsaccharidase activity (p is greater than 0.5) of the intestinaleptihelium was unaltered. The results indicate that the inhibition may be due to interaction between the intestinal epithelium and PE.

Animals↗
PubMed1976

Demonstration of a vitamin B12 binder in pancreatic juice. Effect on the intestinal uptake of vitamin B12.

Determination of vitamin-B12-binding capacity and gel filtration of human pancreatic juice (HPJ) and rat pancreatic juice (RPJ) demonstrated a vitamin B12 binder different from gastric intrinsic factor (IF). The results also indicated the presence of the pancreatic B12 binding in human duodenal juice. The binder in RPJ had no significant effect on the uptake of 57CoB12 and 57CoB12 bound to rat IF by perfused rat intestinal segments (p greater than 0.5; p greater than 0.1). The binder in HPJ had no effect on the uptake of unbound 57CoB12 or 57CoB12 bound to human IF by guinea pig intestinal brush borders (p greater than 0.05; p greater than 0.1). The results indicate that the pancreatic vitamin B12 binder does not influence the intestinal uptake of vitamin B12.

Animals↗
PubMed1976

Bile acid and detergent interaction with radioassays based on coated charcoal.

We tested the radioassays for cyclic AMP and human gastrin, both involving separation on coated charcoal, for interaction with bile acids and detergents, and found a concentration-dependent interaction of taurocholic and glycocholic acid as well as of the surfactant Triton X-100 and sodium laurylsulfate in both assays. The interaction was detectable from concentrations of 0.5 mmol of bile acid per liter or 625 mg of detergent per liter, giving rise to falsely decreased gastrin values and falsely increased or decreased values for cyclic AMP. The interactions demonstrated may be a general effect on all radioassays that are based on the use of coated charcoal in the separation of free from bound ligands.

Bile Acids and Salts↗
PubMed1976

Intestinal absorption of vitamin B12 in patients with chronic pancreatic insufficiency and the effect of human duodenal juice on the intestinal uptake of vitamin B12.

The mean absorption of vitamin B12 (Schilling test) was 13.1 +/- 1.0 (% +/- S.E.M.) in 21 patients with chronic pancreatic insufficiency and 17.6 +/- 1.4 in 13 control patients (p less than 0.01). There was no correlation between pancreatic bicarbonate production after secretion stimulation and vitamin B12 absorption in the patient group (r = 0.117). Human duodenal juice reduced the uptake of 57CoB12-rat intrinsic factor (IF) by perfused rat small intestinal segments in vivo (p less than 0.01) as well as the uptake of 57CoB12-human IF by purified guinea-pig intestinal brush borders in vitro (p less than 0.01). The results confirm reduced absorption of vitamin B12 in chronic pancreatic insufficiency, but the mechanism remains uncertain.

Adolescent↗
PubMed1972

Studies on deoxyribonucleic acid-dependent ribonucleic acid polymerase from Escherichia coli. Variations of the enzyme activity during growth.

1. RNA polymerase activity of Escherichia coli extracts prepared from cells in exponential and stationary phases of growth, when measured in the presence and absence of external template, showed significant qualitative differences. 2. In both extracts, polymerase activity was higher when assayed with external template, suggesting the presence of a pool of enzyme not bound to cellular DNA. 3. In the crude extract, the fraction of enzyme bound to cellular DNA is higher during the exponential phase of growth. 4. A method is described for the purification of enzyme molecules not tightly bound to cellular DNA from exponential- and stationary-phase cultures. 5. Purified enzyme preparations showed differences in template requirement and subunit composition. 6. On phosphocellulose chromatography of stationary-phase enzyme, a major portion of polymerase activity eluted from the column with 0.25m-KCl. In the case of exponential-phase enzyme, polymerase activity eluted from a phosphocellulose column mainly with 0.35m-KCl. 7. Enzyme assays done with excess of bacteriophage T(4) DNA showed a strong inhibition of stationary-phase enzyme by this template. The exponential-phase enzyme was only slightly inhibited by excess of bacteriophage T(4) DNA.

Chemical Phenomena↗
PubMedDate not supplied

Lysosomal heterogeneity of dipeptidyl peptidase II active on collagen-related peptides.

The subcellular distribution of dipeptidyl peptidase II (DPP II) in the rat kidney cortex, as determined by subfractionation of the mitochondrial/lysosomal fraction by rate sedimentation, indicated that this enzyme is mainly associated with the large, fast sedimenting lysosomes (protein droplets). The small lysosomes, on the other hand, displayed considerable size heterogeneity as indicated by the broad distribution of DPP II; cathepsin B, and a tripeptidyl peptidase active on Gly-Pro-Met-2-naphthylamide at pH 4 (TPP 4). Cathepsin D and N-acetyl-beta-D-glucosaminidase were limited primarily to the slower-sedimenting, small lysosomes. Equilibrium banding in sucrose gradients of the two main DPP II-containing lysosomal populations showed that the large lysosomes banded at a density of 1.235-1.24 g/ml while small lysosomes banded at three densities: 1.11-1.15 g/ml (lysosomal fragments), 1.20 g/ml (light lysosomes), and 1.235 g/ml (dense lysosomes). Identical distribution pattern were obtained for DPP II using either Lys-Ala-7-(4-methyl)coumarylamide or Gly-Pro-2-naphthylamide as the substrate at pH 5.5 and 5.0, respectively. Notably, DPP II and TPP 4, and cathepsin B as well, gave banding densities and distributions that were consistent with a lysosomal localization. Since triplets of the Gly-Pro-X-type released by the TPP 4 are ideal substrates for DPP II, the integrated action of tripeptidyl and dipeptidyl peptidases could make a novel contribution to the renal depolymerization and reabsorption of polypeptides, in particular the proline-rich, collagen-derived sequences that possess repeating-triplet primary structures.

Aminopeptidases↗
PubMedDate not supplied

Absorption of bismuth from two bismuth compounds before and after healing of peptic ulcers.

BACKGROUND/AIMS: Previous reports state that there is absorption of bismuth through active peptic ulcers. It was therefore of interest to investigate the extent of absorption in patients at the ulcer and post-ulcer stages. METHODOLOGY: Twenty H. pylori-positive patients with gastroscopically verified gastric or duodenal ulcers were randomly allocated to ingest 3000 mg bismuth subnitrate (BSN) (10 patients) or 480 mg colloidal bismuth subcitrate (CBS) (10 patients). Bismuth serum concentration in 12 samples drawn during the first 4 hours after drug intake was analyzed and the area under the curve (Bi-AUC) was calculated. Anti-H. pylori therapy with amoxicillin and lanzoprazole eradicated H. pylori in 10 patients and healed the ulcers in all patients 4 weeks after therapy ended, then the bismuth absorption test was repeated. RESULTS: There was no significant difference between ulcer- and post-ulcer Bi-AUC for patients receiving BSN or for patients receiving CBS. On a molar basis, CBS gave a 17.4-fold greater absorption of bismuth compared to BSN. CONCLUSIONS: The presence of an active ulcer does not significantly influence the absorption of bismuth from CBS or BSN.

Administration, Oral↗