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Biomedical subjects

S N Rasmussen

Publications and source records attributed to S N Rasmussen.

At least 127 records · Page 7Linked to original sources
PubMed1982

5-aminosalicylic acid in a slow-release preparation: bioavailability, plasma level, and excretion in humans.

The release pattern, bioavailability, and kinetics of a 5-aminosalicylic acid tablet with sustained release were studied in humans. Six ileostomy patients received a single dose (500 mg). Eight and 48 h later, respectively, 58% and 65% of the dose was recovered in the ileostomy effluents, either as 5-aminosalicylic acid still retained in the preparation, free 5-aminosalicylic acid or acetyl-5-aminosalicylic acid. Fourteen healthy volunteers took 1500 mg of 5-aminosalicylic acid per day for 6 days and a steady state plasma acetyl-5-aminosalicylic acid concentration was reached on day 5 (1.1-2.9 microgram/ml). 5-Aminosalicylic acid was not detected in the plasma. At steady state, 40% of the 24-h dose was recovered from feces, and 53% from the urine. The sustained-release preparation studied provides sufficient amounts of 5-aminosalicylic acid to all parts of the gut and its curative effect in ulcerative colitis and Crohn's disease should be examined in controlled trials.

Adult↗
PubMed1979

L-thyroxine treatment of diffuse non-toxic goitre evaluated by ultrasonic determination of thyroid volume.

The effect of a daily dose of 150 micrograms l-thyroxine for one year was studied in forty-five patients with diffuse non-toxic goitre. Thyroid volume was evaluated by ultrasonic scanning. A decrease in the median value of the thyroid volume of about 20% was found after 3 months of therapy and no further change in the median value was observed in the following 9 months of treatment. About 50% of the patients showed a response to therapy and about 30% obtained normal size of the thyroid gland. Median value of the thyroid volume returned to pretreatment value 3 months after thyroxine therapy was stopped. A considerable increase in serum T4 and free T4 index was noted after 3 months of therapy and these elevated values persisted unaltered during the following 9 months of treatment. Serum T3 was studied before and after 3 months of thyroxine therapy in eleven of the patients. A small and insignificant increase in serum T3 and free T3 index was observed.

Adult↗
PubMed1979

Lysine transport across rat jejunum: distribution between the transcellular and the paracellular routes.

Transport of lysine across the rat jejunum has been studied measuring transmural fluxes, Jms and Jsm, under short-circuit conditions, influx across the brush-border membrane, Jmc, under open-circuit and voltage-clamp conditions, and steady-state uptake by the isolated mucosa. 1. Jlysmc can be described as the sum of a saturable process with a Kt of 3 mM and a Jmax of 2.25 micromole/cm2.hr and a diffusional component corresponding to a lysine permeability of 0.014 cm/hr. Also Jlysms is well described as the sum of a saturable process and a diffusional contribution described by the same permeability as for Jlysmc. 2. The effects of the transmural p.d. on Jlysmc indicate that at 60 mM this flux includes a diffusional contribution, which corresponds to a lysine permeability of 0.014 cm/hr. 3. The passage of an electrical current across the gut wall changes the electrical conductance as expected for a cation-selective epithelium. The effect of a mucosa to serosa current on the Jms value of mannitol provides confirmation of the expected current effect on transepithelial volume flow. These effects on conductance and solute flux, together with the electrostatic effect on lysine movements, suffice to account for the p.d. effects on Jmc, Jms, and Jsm of lysine. 4. Jlyssm is in a saturable manner stimulated by increasing concentrations of D-glucose. At higher (10 mM) concentrations of lysine this effect leads to a net secretion of lysine. Qualitatively and quantitatively these effects are consistent with the model of a glucose-induced fluid circuit between the mucosal solution and the lateral intercellular spaces. 5. All observations are consistent with a paracellular, transepithelial pathway for lysine, which includes the lateral intercellular spaces. 6. The transport of lysine across the basolateral membrane is analysed. Togethet the data on transcellular passage of lysine are very similar to those reported for rabbit ileum, except that more than one transport process could not be demonstrated.

Animals↗
PubMed1978

Determination of renal volume by ultrasound scanning.

In patients with renal hypertension, determination of renal volume may be valuable for evaluating possible compensatory hypertrophy for correlating renal size to renal function, and for evaluating the transplanted kidney in relation to rejection and its response to therapy. We performed parallel transverse ultrasonic scans through each kidney and computed volume based on the cross-sectional areas outlined on the scans. In 16 autopsy studies a highly significant correlation between calculated and true values were obtained, rs = 0.847, p less than 0.001. The 5th and 95th percentiles of the median divergence were -21 and 27 ml respectively. In 30 healthy subjects, double determinations showed 5th and 95th percentiles of the median interobserver variation of -7 and 3 ml respectively. There was no demonstrable difference between volumes of right and left kidneys, and no difference in relation to sex. Total renal volume was most accurate when correlated with the body weight, rs = 0.698, p less than 0.001. Normal values of total renal volume per kilogram of body weight were 4.3 to 8.0 ml/kg. In normal subjects, the smallest kidney's volume should not be less than 37% of the total renal volume.

Adult↗
PubMed1977

Paracellular permeability of extracellular space markers across rat jejunum in vitro. Indication of a transepithelial fluid circuit.

1. The characteristics of [51Cr]EDTA, [3H]methoxyinulin ([3H]MI), [14C]polyethylene glycol-4000 ([14C]PEG), and [3H]mannitol as markers of the extracellular space (e.c.s.) of isolated mucosa from the rat small intestine have been examined. 2. Unidirectional transmural fluxes across the rat jejunum of [3H]MI, [14C]PEG and [3H]mannitol have been measured in the absence of glucose or in the presence of 28 mM glucose. 3. Assuming that [14C]PEG does not enter the cells, [51Cr]EDTA and [3H]mannitol seem to have access to approximately 50 and 90% of the intracellular water respectively. 4. The commercially availabel [3H]MI had access to a space which exceeded th [14C]PEG space by 10%. Upon purification by gel filtration the high molecular weight fraction of the [3H]MI provided estimates of the e.c.s. identical with the estimates obtained with [14C]PEG. 5. For all the markers used the e.c.s. estimates remained constant between the 40th and 80th min of incubation. 6. In the absence of glucose the transepithelial net fluxes of each of the different markers were zero. In the presence of 28 mM glucose the serosato-mucosa fluxes of all markers were dramatically increased. The ratio between the serosa-to-mucosa and the mucosa-to-serosa fluxes increased in the order [3H]mannitol greater than [3H]MI greater than [14C]PEG. 7. The effect of glucose on the flux ratio of the marker substances suggests that glucose-induced net water transport to the serosa side of the gut wall represents the difference between a transcellular net water transport to the serosal side and a significant paracellular net water transport through the lateral intercellular spaces to the mucosal solution.

Animals↗
PubMed1977

Step function input to the rat kidney by shifting between auto- and alloperfusion.

A technique is described that permits instantaneous shifts from autoperfusion of the left kidney of an "experimental" rat to alloperfusion of the same kidney from a "pump" rat (or vice versa). Renal arterial and venous pressures are maintained at normal levels during alloperfusion. The kidney has proved to work satisfactorily during both auto- and alloperfusion as judged from measurements of renal blood flow, urine volume flow, urine osmolality, and fractional extraction of inulin and PAH. The vascular dead space of the system is extremely small. If the blood of the pump rat-experimental rat has been equilibrated with indicator, shifting from auto- to alloperfusion constitutes a practically pure step washin to/washout from the kidney. Reverse effects are obtained by shifting from allo- to autoperfusion. Compared with the bolus injection technique, recirculation problems are minimized because the perfused vascular volume of a single kidney is small compared with the whole-blood volume of the rat.

Animals↗
PubMed1977

Leucocyte migration test with autologous colonic mucosa as antigen in patients with ulcerative colitis.

The leucocyte migration agarose technique (LMAT) was applied in a study of the migration of peripheral leucocytes in 16 patients with ulcerative colitis using three different autologous types of tissue as antigen: rectal mucosa, skin and buccal mucosa. In all cases the migration indices were within normal limits, and they did not differ from a group of control patients suffering from peptic ulcer, irritable colon or haemorrhoidal tumours. The present study does not support the theory of cellular hypersensitivity against colonic mucosa in patients with ulcerative colitis.

Adult↗