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Biomedical subjects

S Smeds

Publications and source records attributed to S Smeds.

At least 73 records · Page 4Linked to original sources
PubMed1978

Change of the protein composition of the thyroid colloid during treatment with propylthiouracil and thyroxine: a microgel electrophoretic study of single rat thyroid follicles.

Prophylthiouracil and thyroxine were given daily to rats for 4 weeks. Samples of colloid were collected in vivo from the superficial thyroid follicles during this period and their protein composition was analysed by gel electrophoresis. It was observed that the aggregates of thyroglobulin, i.e., the 27-S thyroid iodoprotein and the heavier fractions, were reduced to 50% after 1 week and were almost absent after 2 weeks. A faster migrating thyroglobulin fraction was observed in the samples of colloid and in the homogenate of the whole gland after 48 h of treatment. During the following period of treatment there was an increase in the relative amount of the faster migrating thyroglobulin fraction compared to 19-S thyroglobulin in the colloid, the former comprising approx. 75% of the globulins after 4 weeks, It can be concluded that propylthiouracil inhibits the formation of the 27-S iodoprotein and that a structurally altered and iodine-poor thyroglobulin fraction is accumulated in the follicle lumen.

Animals↗
PubMed1977

On the distribution of thyroglobin and larger iodoproteins in single rat thyroid follicles.

The distribution of the large iodoproteins in the lumen of thyroid follicles was tested. Samples of the colloid in rat thyroid follicles were obtained in vivo by micropuncture of superficial follicles in the isthmus of the gland. One sample was collected per follicle and several follicles were punctured in each gland. The protein composition of the samples was analysed by microgel electrophoresis. The protein separation patterns were recorded by microdensitometry after staining of the proteins and the amount of protein in the fractions was estimated from the densitometric recordings. Thyroglobulin (TG) and the aggregates of TG--here designated the S-TG fractions--were present in all samples of colloid. It was observed that there was a significant positive co-variation between TG and S-TG when the colloid contained only TG, S-TG and a prealbumin fraction. When the albumin-like protein was present in the samples the co-variation was less significant. The results show that the relative amount of the aggregates of TG is constant in the albumin free colloid and that these aggregates most probably are randomly distributed in the follicle lumen. The results further indicate that the aggregates of TG are non-randomly distributed in the larger peripheral follicles when the colloid contains the albumin-like protein.

Animals↗
PubMed1977

A microgel electrophoretic analysis the colloid in single rat thyroid follicles during thyroxine suppression.

A sequential study of the effect of thyroxine (T4) on the protein composition of the colloid in the rat thyroid gland has been carried out in 24 rats. Daily ip injections of 20 mug thyroxine were given and the colloid was analyzed after 1, 2, 3 and 4 days and 1, 2 and 3 weeks. The protein constituents were separated by microgel electrophoresis and measured by microdensitometry. The incorporation of [3H]leucine into the thyroglobulin fraction and into the albumin-like protein in the homogenate of the gland was analyzed after T4 suppression for 2 days. The 2 h thyroidal iodine uptake was analyzed during the first week of T4 administration. During the second and the third day of T4 administration, the amount of 27S and larger complexes of thyroglobulin was reduced by 30-40 per cent and the amount of the albumin-like protein was significantly increased and present in almost all samples. Preliminary data indicated that during the same period the relative amount of [3H]leucine activity was increased in the albumin-like protein fraction compared to the thyroglobulin fraction in the thyroid. It is concluded that the exocytotic vesicles contain the albumin-like protein. The results further indicate that the administration of T4 temporarily changes the relative rates of formation of thyroglobulin and of the albumin-like protein in the follicle.

Animals↗
PubMed1977

Protein concentration of the rat thyroid colloid during thyroxine treatment.

Sprague-Dawley rats were given daily doses of 20 mug thyroxine for varying periods between 1 and 21 days. Samples of colloid were obtained by micropuncture in vivo of follicles in the thyroid isthmus. The protein content of the samples was determined by gel electrophoresis and the volume by a technique based on radioactivity measurement. The relative volume of the follicle lumina was determined by light microscopy. Treatment with thyroxine resulted in an increase in the protein concentration of the colloid. This increase was statistically significant after 2 days and the concentration remained elevated throughout the experimental period. The size of the follicle lumina also increased, most rapidly during the first week. It is suggested that the increase in protein concentration of the colloid during thyroxine treatment is due to inhibition of endocytosis of colloid in combination with the discharge into the follicle lumen of highly concentrated protein.

Animals↗
PubMed1975

Metabolic studies in human skeletal muscle tissue. Evaluation of an in vitro preparation intended for clinical metabolic studies.

An in vitro preparation of human skeltal muscle tissue aimed to be a model for clinical metabolic studies was functionally and structurally characterized. Muscle fibres from biopsy specimens obtained at surgical operations were teased away and collected in incubation vessels for the following determinations: exchangeable water content, extracellular space, potassium content, incorporation rate of labeled leucine into proteins, uptake of labeled cycloleucine, alpha-aminoisobutyric acid (AIB), and 3-o-methy1-glucose into the intracellular space, and the incorporation rate of glucose into various metabolites. After various times of incubation, muscle fibre samples were also taken for light and electron microscopy. During the incubation of the muscle fibres a transient intracellular oedema was demonstrated by electron microscopy and by determination of the exchangeable water content. The restitution of this oedema was associated with an increasing intracellular potassium concentration. Active transport of leucine, cycloleucine and AIB showing competitive inhibition was registered. The incorporation of labeled leucine into proteins was linear during 4 h of incubation and optimal stimulation of this incorporation was demonstrated in the presence of a complete amino acids mixture at a concentration corresponding to 10 times the normal plasma concentration in man. Insulin stimulated the incorporation rate of glucose-carbon into all metabolites and ouabain stimulated its incorporation in to glycogen. Monoidoacetate inhibited the incorporation of glucose into all metabolites.

Amino Acids↗
PubMedDate not supplied

Diagnostic outcome of repeated mammography screening.

Mammographic screening for breast cancer within health service routines was evaluated for the years 1987-1992, with special focus on repeated screening during 1989-1992. The overall attendance rate by women aged 40 to 74 years was 82.8%. During 1989-1992 malignancy was found in 2.6/1000 screened women, giving a 87.4% positive predictive rate at surgery and 95.9% efficiency. Among women aged > or = 45 years, the positive predictive rate was > 94%. Fine-needle aspiration (FNA) biopsy showed invasive cancers in 84% and highly suspected cancer in another 15%; 60% of the lesions were nonpalpable. For first-time (prevalence) screening (1987-1988) the positive predictive rate was 86% and the malignancy yield 6.4/1000. In women aged 40-44 years there were few surgical referrals (1.6%), but the positive predictive rate at surgery was only 48.3%, indicating diagnostic difficulties in young women. The median size of all invasive cancers was 12 mm: 84% were classified as pT1, and 23% had lymph node involvement. Stage II disease was found in 27% of all malignancies. The use of FNA in the diagnostic workup for breast cancer screening is of crucial importance to the maintenance of high positive predictive rates at surgery. Moreover, regular analysis is important even when mammographic screening is incorporated into the routine work of health services.

Adult↗