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At least 847 records · Page 47Linked to original sources
PubMed1985

Determination of the R-protein and the R-protein-vitamin B12-complex in saliva and gastrointestinal juice by FPLC Mono S cationic chromatography.

The binding of vitamin B12 to the two vitamin B12 binding proteins--intrinsic factor and R-protein--in gastrointestinal juice is pH dependent. It is therefore of importance that binding studies are carried out at pH values near the physiological pH of the gastric juice. In the present study the vitamin B12 complexes of the two vitamin B12 binders were separated at a pH of 1.8 using the cationic exchange chromatograph Mono S attached to the fast protein liquid chromatography (FPLC) system. The R-protein concentration was measured in saliva and gastric juice with high accuracy and with highly significant correlation compared to the serum-coated charcoal method of Gottlieb. The method showed a decreased recovery in duodenal juice and in samples with high bile content.

Bile↗
PubMed1988

Human salivary epidermal growth factor, haptocorrin and amylase before and after prolonged exercise.

The concentration of epidermal growth factor (EGF), amylase, haptocorrin, total protein, sodium and potassium was studied in mixed saliva collected from 25 individuals before and after a 2 h-long cross-country race. The concentration was higher following the run for all components studied. The concentrations obtained before and after the run, given as extreme values and median, are 0.2-1.3 (0.4), 0.3-1.5 (0.8) nmol/l for EGF, 15-72 (25), 23-162 (58) nmol/l for haptocorrin and 24-502 (120), 155-5,030 (1,200) kU/l for amylase. The increased concentration of the components studied is most probably caused by an increased adrenergic and VIP'ergic tonus of the individuals after the run.

Adolescent↗
PubMed1989

Cobalamin and its binding protein in rat milk.

Cobalamin and its binding protein, haptocorrin, are present in rat milk throughout the lactation period. The concentration of cobalamin is approximately 0.3-times the concentration of the unsaturated binding protein. The concentration of the unsaturated cobalamin-binding protein varies between 18 nmol l-1 and 16 nmol l-1. The binding protein has a Stokes radius of 2.49 nm when saturated with cobalamin and 2.61 nm when unsaturated. It binds cobalamin over a broad range of pH and is able to bind cobinamide also. With immunohistochemistry, we find haptocorrin immunoreactivity in the mammary glands and in the sebaceous glands of the nipple.

Animals↗
PubMed1985

Absorption of food cobalamins assessed by the double-isotope method in healthy volunteers and in patients with chronic diarrhoea.

To make a food preparation containing radioactively labelled cobalamins, rabbits were given repeated injections with 57Co-labelled cyanocobalamin. The liver was removed, homogenized, and fried for 1 min or boiled for 30 min. Of the radioactivity in the fried homogenate 41.7% was recovered in the centrifuged supernatant compared with 50.8% in the boiled homogenate. The radioactivity in the supernatants had a molecular size close to that of free 57Co-labelled cyanocobalamin. Forty-two per cent of the radioactivity in the whole homogenate had been incorporated into 5-deoxyadenosyl-, 10% into methyl-, and 16.5% into hydroxy-cobalamin. To assess the validity of a double-isotope method for measuring the intestinal absorption of doses of the 57Co-labelled liver cobalamins, 51CrCl3 was used as a non-absorbable marker. In 14 healthy volunteers the correlation coefficient between the absorption measured by the double-isotope technique and the faecal excretion test was highly significant (r = 0.96, p less than 0.005), and there was only a small variation in the 57Co/51Cr ratio in successive stool collections. In 11 patients with chronic diarrhoea there was a significant correlation between the absorption measured by the double-isotope technique and the faecal excretion test (r = 0.92, p less than 0.005), but in some patients there was considerable variation in the 57Co/51Cr ratio in successive stool collections.

Adult↗
PubMed1985

Immunodeficiency syndromes and the gut.

The gastrointestinal tract in immunodeficiency disorders is involved with diseases similar to those seen in the immune competent. However, in some immune deficient states the incidence of gastrointestinal disease is high whereas in others it is no different than in the general population. This review clarifies the unique and specific abnormalities seen in immune deficient states and stresses the newest recognised abnormalities. It highlights the fact that the most frequent and severe abnormalities occur in patients with combined immune deficient states.

Agammaglobulinemia↗
PubMed1987

Effect of gastric anacidity on the release of cobalamins from food and their subsequent binding to R-protein.

Rabbit liver homogenate, labelled in vivo with 57Co, was used to investigate the effect of anacid gastric juice on the release of cobalamins from food and on the cobalamin binding to proteins in humans. The cobalamin release was investigated in vitro by incubating the liver homogenate with native and neutralized gastric juice. The cobalamin release and the amount of cobalamins bound to R-protein were significantly higher with native than with neutralized gastric juice. To investigate the effect of anacidity on cobalamin release in vivo, 14 healthy volunteers were given omeprazole or placebo in a double-blind crossover fashion. 57Co-labelled liver-bound cobalamins were given orally, and aspirates were collected from the stomach and the upper jejunum. After omeprazole gastric anacidity (pH greater than 6.0) was obtained in 11, 12, and 10 individuals after 5, 30, and 60 min, respectively. In the gastric aspirates obtained after omeprazole there was a slight inhibition in cobalamin release after 5 and 30 min (p less than 0.05). In the jejunal aspirates the cobalamin release was close to 90% in both the placebo and the omeprazole experiment, and there was no significant difference in the percentage of cobalamins bound to R-protein in the two groups. The percentage of cobalamins bound to R-protein was much lower in the jejunal aspirates (26.6% and 23.7% in omeprazole and placebo, respectively) than in the gastric aspirates (65.8% and 68.6%).

Animals↗
PubMed1993

Potential of measurements of unsaturated vitamin B12-binding capacity in serial colonoscopic biopsy specimens for global and regional assessments of disease severity in inflammatory bowel disease.

We investigated whether measurements of unsaturated vitamin B12-binding capacity (UBBC), in homogenates of serial colonoscopic biopsy specimens, could be used as objective measures of disease severity in ulcerative colitis (UC) and Crohn's disease (CD). On a regional basis UBBC activity correlated with and showed good agreement with endoscopic and histologic activity scores (r = 0.8 and 0.6, respectively, for UC, and r = 0.7 and 0.7, respectively, for CD). For global assessment aggregate UBBC, endoscopic and histologic scores were compared with standard clinical activity scores. In UC, correlations with the van Hees index were r = 0.7, 0.8, and 0.7, respectively, and UBBC assays accurately reflected both regional and global disease activity. In CD, correlations with the CDAI were -0.1, 0.7, and 0.6, respectively. Thus, aggregate UBBC scores failed to reflect disease activity in CD, in which focal deep ulcers may produce high symptom scores but in which adjacent specimens may show no acute inflammation.

Biomarkers↗
PubMed1986

Biochemical markers in sarcoidosis.

The clinical course of sarcoidosis is varying and unpredictable. Once the diagnosis has been made, the clinician needs simple tests to detect and predict remission or progression, to determine whether treatment is effective or not, and to assess the clinical activity of the disease. Sarcoidosis is a multisystem disease, but the lungs are almost always involved. Traditionally, the clinical management has therefore included chest X-rays and lung function studies. Extrapulmonary lesions have been followed in different ways. Sensitive and reproducible biochemical tests would be helpful in evaluating the clinical course of patients with sarcoidosis, if they measure functions related to the granulomatous inflammation. This review will deal with measurements of serum and urinary calcium, and 1,25-dihydroxyvitamin D. The usefulness of single and serial determinations of lysozyme, angiotensin converting enzyme, beta 2-microglobulin, collagenase, carboxypeptidase and glucuronidase in serum, bronchoalveolar lavage fluid, and other biological fluids will be discussed.

Calcium↗
PubMed1982

Mechanism of uptake of cobalamin into enterocyte mitochondria.

To study the mechanism which cobalamin is taken up by the mitochondria, 57Co-cyanocobalamin-binder complex and freshly prepared mitochondria were prepared from the enterocytes of rats. Subsequently, the binder complex was incubated together with mitochondria in a calcium-containing medium in vitro. Uptake of cobalamin was determined by measuring the radioactivities bound to the mitochondria. Consequently, lysosomal and microsomal binders enhanced cobalamin uptake into the mitochondria, but intrinsic factor did not. It was found that the uptake into the mitochondria was inhibited by previous treatment with calcium-chelating agents. The uptake was completely restored after addition of calcium ions to the mitochondria.

Animals↗
PubMed1983

Effects of aging on intracellular transport of vitamin B12 (B12) in rat enterocytes.

To elucidate the effect of aging on the vitamin B12 (B12) transport in enterocytes, young and old (3-4 months and over 1.5 years, respectively) female rats were studied. Two units of rat intrinsic factor (IF), saturated with 57Co-labeled cyanocobalamin were orally administered, and the amount of B12 absorbed into each subcellular fraction of enterocytes was assayed. Concentration of endogenous B12 in each subcellular fraction was also studied. Absorption of radioactive B12 in the lysosomal fraction was maximum between 2 and 4 hr in each age group. In the older rats, the amount absorbed was lower than in the young rats. The older rats showed a significantly lower value of endogenous B12 in the mitochondria. It has already been reported by us that there exist two B12 binders in enterocytes: lysosomal and microsomal binders. The concentrations of lysosomal and microsomal binders as well as B12 uptake in the mitochondria were significantly lower in the older rats than in the young rats. These data might help to explain the lower B12 absorption in the lysosomal fraction and lower B12 contents in the mitochondrial fraction.

Aging↗
PubMed1986

Binding of cobalamin analogs to intrinsic factor-cobalamin receptor and its prevention by R binder.

It is now known that nonphysiological cobalamin analogs exist in the gastrointestinal tract, but their metabolic behavior is unclear. In this study, [57Co]cobinamide was used to study its affinity to hog intrinsic factor-cobalamin (IF-Cbl) receptor which has no species specificity against human IF-Cbl receptor, and its relation to human saliva R binder. Cobinamide was prepared from [57Co]cyanocobalamin and separated by paper chromatography. Human IF-Cbl complex was bound to IF-Cbl receptor but free cyanocobalamin was not. Although R binder-cobinamide was not bound to the IF-Cbl receptor, free cobinamide was bound to the IF-Cbl receptor to a significant extent (about one-half of IF-cyanocobalamin binding to the IF-Cbl receptor). We then investigated the binding of cobinamide to R binder and trypsin-treated R binder. Association constant of cobinamide binding to the IF-Cbl receptor was 1.0 X 10(9) M-1 which was much lower than that of cobinamide binding to trypsin-treated R binder and to untreated R binder. Further study indicated that cobinamide binding to the IF-Cbl receptor was blocked by the addition of R binder and also by trypsin-treated R binder. We conclude that one of the roles of R binder is to prevent binding of free cobalamin analogs to the IF-Cbl receptor in the gut.

Cobamides↗