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Biomedical subjects

K Hjelt

Publications and source records attributed to K Hjelt.

62 records · Page 4Linked to original sources
PubMed1977

Determination of 58Co-vitamin B12 absorption in pernicious anemia by use of whole-body counting: Reproducibility and control of gut transit time.

In 15 patients with pernicious anemia, the fractional retention of 58Co-cyanocobalamin (FRB12) without administration of intrinsic factor (IF) averaged 4.9% (range 0-12.7). With administration of IF, FRB12 averaged 32.7% (range 26.6--42.3) in the patients and 65.6% (range 38.8--84.6) in 16 control subjects. The gut transit time for vitamin B12 was evaluated from the excretion of radiopaque pellets given concomitantly with the 58Co-vitamin B12. The retention of the pellets was positively correlated to that of the non-absorbed 58Co-B12. Control of the gut transit time is recommended at each examination of FRB12 in order to avoid falsely high values due to the retention of non-absorbed 58Co-B12. We found a good reproducibility of FRB12 when determined in fasting subjects, and it is therefore unnecessary to give the patients a B12-free meal prior to the examination. As the FRB12 in all probability is only a little lower than the fractional absorption, the present method is applicalble for the determination of B12 absorption.

Administration, Oral↗
PubMed1977

Effect of amiloride on electrical activity and electrolyte transport in human colon.

It is not known whether factors other than Na transport are involved in generating the electrical potential difference (PD) across the human colonic wall. Therefore, experiments were performed in which the effect of amiloride on PD and ion transport was evaluated in the in vitro short-circuited human colon. In control periods the short-circuit current (Isc) was 2.9 +/- 0.3 (mean +/- S.E.M.) muEq per hr per cem2, while the corresponding net transfer of Na and Cl was 4.6 +/- 0.4 and 1.4 +/- 0.1 respectively. The residual flux was insignificantly different from zero. Amiloride caused a prompt, but reversible, decrease in Isc, PD, and conductance when added to the mucosal sie,dbut only a relatively small reduction of the mucosa to serosa fluxes of Na occurred. Bidirectional Cl fluxes were unchanged while the residual flux increased significantly. It is proposed, therefore, that some ions other than Cl (presumably mucosa to serosa fluxes of H and/or serosa to mucosa fluxes of HCO3) are the main counter ions for actively transported Na in the large bowel. Experiments performed in vivo showed that the rectal PD decreased exponentially from -46 mV +/- 0.8 TO -27 MV +/- 0.3 (mean +/- S.E.M.) following rectal instillation of 10-3 M amiloride. The half-time required for this effect was less than 13 seconds.

Adult↗
PubMedDate not supplied

Retrospective clinical study of hypersensitivity reactions to aztreonam and six other beta-lactam antibiotics in cystic fibrosis patients receiving multiple treatment courses.

A total of 2,793 courses of treatment with seven beta-lactam antibiotics were administered to 121 cystic fibrosis patients chronically infected with Pseudomonas aeruginosa, and the patients were evaluated with respect to clinical hypersensitivity reactions. Seventy-five patients (62%) experienced 125 reactions, for an overall frequency (based on the number of courses) of 4.5%. Immediate reactions occurred in 34 patients (28.1%) during 53 courses (1.9%). The highest rate of reactions involved piperacillin (50.9% of patients), and the lowest rate involved imipenem and aztreonam (4.0% and 6.5% of patients, respectively); intermediate reaction rates were noted for carbenicillin (23.6% of patients), azlocillin (20.8%), cefsulodin (17.1%), and ceftazidime (13.0%). Cross-reactivity did not appear to be a major problem. Reactions to aztreonam seemed to be restricted to a small group of patients with a high propensity for beta-lactam hypersensitivity.

Anti-Bacterial Agents↗
PubMedDate not supplied

Concentrations of IgA, secretory IgA, IgM, secretory IgM, IgD, and IgG in the upper jejunum of children without gastrointestinal disorders.

Jejunal fluid was collected from 40 children aged 1-12.2 years and from 10 adults (age 20-25 years) who were without gastrointestinal disorders. They were intubated pernasally with a special tube system that made it possible to avoid contamination from the upper respiratory tract secretions. Quantitation of immunoglobulin A (IgA), secretory IgA (SIgA), IgM, SIgM, IgD, IgG, and albumin was performed by double sandwich enzyme-linked immunosorbent assay. IgA was the dominating immunoglobulin in jejunal fluid, showing the highest concentrations, followed in order by IgM, IgG, and IgD. The IgD concentrations were about 1,000 times less than in plasma of age-matched children. The immunoglobulin concentrations did not show any age-related differences, except for IgG and for the SIgA/IgA ratio. The former declined with children's age (p less than 0.02), whereas the latter was significantly higher in adults (interquartile range: 97-100%) than in young children aged 1-less than 5.5 years (interquartile range: 55-94%) (p less than 0.001). This indicates an age-related decline in leaking from gut mucosa. The concentrations of SIgA and SIgM showed a positive correlation (p less than 0.001). The majority of IgA and IgM were estimated to be locally produced, whereas IgD and IgG were transudated from plasma.

Adult↗
PubMedDate not supplied

Reliability of a new technique for the determination of vitamin B12 absorption in children: single stool sample test--a double isotope technique.

The fractional vitamin B12 absorption (FAB12) was determined in 39 patients with various gastrointestinal diseases by a double-isotope technique, employing a single stool sample test (SSST), as well as a complete stool collection. The age of the patients ranged from 2.5 months to 16.2 years (mean 5.0 years). The test dose was administered orally and consisted of 0.5-4.5 micrograms of 57CoB12 (approximately 0.05 microCi), carmine powder, and 2 mg 51CrCl3 (approximately 1.25 microCi) as the inabsorbable tracer. The wholebody radiation to a 1-year-old child averaged only 20 mrad. The stool and napkin was collected and homogenized by addition of 300 ml "chromium sulfuric acid." A 300-ml sample of the homogenized stool and napkin, as well as 300 ml chromium sulfuric acid (75% v/v) containing the standards, were counted in a broad-based well counter. The FAB12 determined by SSST employing the stool with the highest content of 51Cr (which corresponded to the most carmine-colored stool) correlated closely to the FAB12 based on complete stool collection (r = 0.98, n = 39, p less than 0.001). The reproducibility of FAB12 determined by SSST was assessed from double assays in 19 patients. For a mean value of 12%, the SD was 3%, which corresponded to a coefficient of variation (CV) of 25%. The excretion of 57Co and 51Cr in the urine was examined in six patients with moderate to severe mucosal damage and was found to be low.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Vitamin B12 absorption capacity in healthy children.

B12 absorption was investigated in 47 healthy children aged 7 months to 15.8 years (median 4.9 years). The patients had either recovered from giardiasis, the post-gastroenteritis syndrome, or had celiac disease in remission (treated with a gluten-free diet). The B12 absorption was measured by a double-isotope technique using 57CoB12 and 51CrCl3, the latter being the inabsorbable marker. The radiation dose was minimal. The results were presented as fractional absorption of B12 (FAB12). Within the different age groups, the absorption test was performed by means of the following oral amounts of B12: 0- less than 1 year, 0.5 microgram; 1-3 years: 1.7 micrograms, 4-6 years, 2.5 micrograms; 7-10 years; 3.3 micrograms; and 11-15 years, 4.5 micrograms. When using these oral amounts of B12, the medians (and ranges) of FAB12 were found to be: 1-3 years (n = 18), 37% (16-80%); 4-6 years (n = 10), 27% (19-40%); 7-10 years (n = 9), 32% (21-44%); and 11-15 years (n = 8), 27% (19-59%). The FAB12 in two children aged 7 and 11 months was 31% and 32%, respectively. These results may be interpretated as reference values for B12 absorption in children. Further absorption tests were performed in seven children representing the four age groups from 1 to 15 years. When a high oral amount of B12 was given (i.e., three times the saturation dose), the FAB12 ranged from 0 to 20% (median 9%), whereas a low amount (i.e., one-ninth of the saturation dose) produced fractional absorptions from 65 to 82% (median 74%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗