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Biomedical subjects

K J Andersen

Publications and source records attributed to K J Andersen.

At least 55 records · Page 3Linked to original sources
PubMed1985

A test strip method for visual and reflectometric reading of blood glucose.

A double field glucose oxidase test strip, B-M Haemoglucotest 1-44 R, was tested for stability of reaction and comparability of visual and reflectometric readings (evaluating four reflectometers) with a standard laboratory glucose oxidase analysis and showed excellent precision and accuracy within the whole range when estimated immediately. Readings after 1 and 7 days showed a systematic and increasing error with time, with spuriously high and low values in the lower (less than or equal to 4.0 mmol/l) and higher (greater than or equal to 8.1 mmol/l) part of the range, respectively. In the lower range, however, the error was in the order of 1 mmol/l only, thus stability of the reaction allows mailing the strips to the clinic for rechecking.

Blood Glucose↗
PubMed1983

The effect of sampling conditions on rat plasma renin.

1. Renin concentration and activity were measured in blood samples taken in the animal house from 3 groups of rats. The first group received no anesthesia, the second group was anesthetized with ether, while the third group was sampled during pentobarbital anesthesia. After 1 week the same procedure was performed 1 hr after the rats were transferred to the research laboratory. 2. Renin concentration and activity increased after pentobarbital anesthesia, while only renin activity was increased during ether anesthesia. 3. Transport had no additional effect on unanesthetized or ether anesthetized rats, while an additional activity was observed after pentobarbital.

Animals↗
PubMed1983

Enzyme activities in human and rat jejunal mucosa.

To define reproducible conditions for the homogenization of small-intestinal biopsy samples, tissue homogenization has been studied by the use of three different homogenizers. Tissue samples of increasing wet weights (0.5-10.8 mg) were homogenized in a fixed volume (1 ml) before DNA and protein were determined. The DNA to protein ratio was calculated for all wet weights and used as a measure for reproducible homogenization. The minimum tissue wet weight needed for analysis (2 mg) was determined from the values obtained for the DNA to protein ratio. Highly sensitive techniques are described in detail for the assay of brush border (maltase, lactase, sucrase, neutral alpha-glucosidase, alkaline phosphatase, gamma-glutamyl transferase, leucyl-beta-naphthylamidase), basolateral membrane (5'-nucleotidase), and mitochondrial (succinate dehydrogenase) marker enzymes and for four acid hydrolases (acid phosphatase, acid beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase, acid diesterase) in human and rat jejunal mucosa. Linear kinetics have been established for all enzyme assays. The optimal dilution of tissue homogenate for the assay of the various enzymes has been determined to enable the determination of a maximum number of enzymes in each homogenate. The range of enzyme activities in samples of human and rat jejunal mucosa has been determined.

Adult↗
PubMed1983

Jejunal mucosal enzymes in untreated and treated coeliac disease.

A series of marker enzymes for brush borders, basolateral membrane, and lysosomes were assayed in mucosal biopsy specimens from patients with untreated and treated coeliac disease and from controls. The brush border enzymes lactase, sucrase, neutral alpha-glucosidase, alkaline phosphatase, and leucyl-beta-naphthylamidase showed reduced activities in the untreated state and complete or partial normalization during treatment. The lysosomal marker enzyme acid phosphatase increased in activity in untreated coeliac disease and was normalized by treatment. The brush border enzyme gamma-glutamyl transferase was nearly normal in untreated patients and slightly increased in treated patients. The basolateral membrane marker, 5'-nucleotidase, was reduced both in untreated and treated patients, whereas the lysosomal marker N-acetyl-beta-glucosaminidase was normal in the untreated state and decreased during treatment. The possible pathogenetic role of the three latter enzymes in coeliac disease is discussed. The patterns of the other enzymes are suggested to be attributable to the morphologic changes in the mucosa.

Adult↗
PubMed1983

Enzyme activities in jejunal biopsy samples from patients with adult coeliac disease with and without steatorrhoea.

Highly sensitive techniques have been used for the assay of a range of marker enzymes including lactase, sucrase, alkaline phosphatase, leucyl-beta-naphthylamidase (brush border), and 5'-nucleotidase (basolateral membrane) in jejunal biopsy homogenates from patients with adult coeliac disease with and without steatorrhoea and from a control group. The absorption of D-xylose and vitamin B12 was compared in the two groups with coeliac disease. All enzymes assayed were equally depressed in both groups of coeliac disease as compared with the controls. The absorption of D-xylose and vitamin B12 were reduced in the patients with steatorrhoea compared with those without steatorrhoea. The findings suggest that lack of steatorrhoea in some patients with coeliac disease is due to better preservation of the ileal function rather than to a less severe jejunal mucosal injury.

5'-Nucleotidase↗
PubMed1983

Enzymatic activities in jejunal biopsy specimens from patients with the stagnant-loop syndrome.

The activity of the marker enzymes lactase, sucrase, neutral alpha-glucosidase, alkaline phosphatase, gamma-glutamyl transferase, leucyl-beta-naphthylamidase (brush border); 5-nucleotidase (basolateral membrane); and acid phosphatase and N-acetyl-beta-glucosaminidase (lysosomes) in jejunal biopsies from patients with the stagnant-loop syndrome and controls was studied. The activity of gamma-glutamyl transferase was increased in the patient group; the activity of the other enzymes did not differ significantly in patients and controls. The DNA to protein ratio was increased in the patient group. The results do not support the hypothesis of epithelial damage in the human stagnant-loop syndrome.

5'-Nucleotidase↗
PubMed1982

A study of the distribution of acyl-CoA hydrolases and acyl-L-carnitine hydrolases in guinea-pig small intestine.

1. Acyl-CoA hydrolase activities, using palmitoyl-CoA and decanoyl-CoA as substrates, were highest in the proximal part and lowest in the distal part of the guinea-pig small intestine. Butyryl-CoA hydrolase activity was not found in any of the homogenates. 2. The acyl-CoA hydrolases showed a complex subcellular distribution when compared to classical marker enzymes. The specific activity of the hydrolase was highest in the microsomal fraction, and lowest in the soluble fraction when palmitoyl-CoA was used as substrate. When decanoyl-CoA was used as substrate, highest activity was found in the mitochondrial/lysosomal fraction and lowest in the microsomal fraction. 3. Gel filtration on an ultrogel AcA-44 column separated the palmitoyl-CoA hydrolase of the cytosol fraction into three or four fractions. 4. Palmitoyl-carnitine hydrolase was present in the microsomal and the nuclei fractions. The distribution was mostly similar to the alkaline phosphatase suggesting a brush border localization.

Animals↗
PubMed1982

Brush border and lysosomal marker enzyme profiles in duodenal mucosa from coeliac patients before and after organ culture.

Five brush border and 2 lysosomal enzymes were measured in duodenal tissue explants from 21 children and young adults (16 coeliac and 5 non-coeliac) before and after organ culture. Reduced activity of brush border enzymes and increased activity of lysosomal enzymes were recorded in flat mucosas from coeliac patients compared with remission coeliac explants and biopsy specimens from non-coeliac controls. Slightly increased activity of alkaline phosphate and sucrase was recorded during culture (24 h) of coeliac explants. Coeliac specimens in the exacerbation state showed increased activity of acid phosphatase after culture in the presence of gluten, whereas gluten did not provoke detectable alterations in brush border enzyme activities during culture unless the wet weight of material was 1.5 mg or more. In such explants lower activity of brush border enzymes was measured after in vitro gluten exposure than after culture on gluten-free medium. Mucus removed from the specimen surface after culture contained considerable amounts of brush border enzymes and reflected the variations in the tissue homogenates. Culture media contained smaller quantities of enzymes.

Acetylglucosaminidase↗
PubMed1979

A rapid polyethylene glycol assay for gastric intrinsic factor.

The use of polyethylene glycol (mol. wt 4000) in a rapid radioassay for intrinsic factor is reported. The assay is based on the observation that polyethylene glycol precipitates the intrinsic factor-vitamin B12 complex in the presence of serum from patients with pernicious anaemia having auto-antibodies against intrinsic factor. The assay was found highly reproducible (CV 1.8%) and well correlated to the classical method using coated charcoal in the separation step.

Anemia, Pernicious↗
PubMed1979

The effect of proteolytic enzymes on the vitamin B12-binding proteins of human gastric juice and saliva.

Pepsin had no effect on the vitamin B12 binder in human saliva (R-binder), while trypsin was found to reduce the apparent molecular weight of the R-binder and to release vitamin B12 from the R-B12complex of human saliva and human gastric juice (HGJ). Trypsin had no effect on the molecular weight and biological activity of intrinsic factor (IF) in HGJ, as demonstrated by gel filtration on Sephadex G-150 and the uptake of IF-B12 by guinea pig intestinal brush borders. An extract of purified guinea pig intestinal lysosomes was also without effect on the molecular weight and the biological activity of IF but was found to release vitamin B12 from the R-B12 complex. The results support the observation that the external pancreatic secretion corrects malabsorption of vitamin B12 by an effect on the non-IF protein in the intestinal juice. Moreover, the results indicate that lysosomal enzymes are not involved in the intestinal absorption of vitamin B12.

Animals↗
PubMed1978

Intrinsic factor-mediated binding of cyanocobalamin to cholestyramine.

The intrinsic factor-mediated binding of cyanocobalamin to cholestyramine was studied in vitro under varying conditions of pH, added electrolyte, and bile salt. The intrinsic factor-cyanocobalamin complex was adsorbed strongly by the resin at pH 3 in the presence of neutral salt and low concentrations of glycocholic acid. An increase in glycocholic acid concentration as well as neutral pH decreased the observed binding, although significant amounts of cyanocobalamin-intrinsic factor complex remained bound after incubation at pH 6.8. Cyanocobalamin alone was not adsorbed by the resin.

Binding Sites↗