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Biomedical subjects

L Rasmussen

Publications and source records attributed to L Rasmussen.

179 records · Page 10Linked to original sources
PubMedDate not supplied

Cellular immunity to herpes simplex infection in humans.

A comparison of lymphocyte interferon production and transformation as in vitro parameters of cellular immunity to herpes simplex in humans in different types of mononuclear cell cultures is reported. Mononuclear cells were purified on Ficoll-Hypaque gradients and nylon fiber columns (purified T lymphocytes). Reactivity was then compared to that observed in autochthonous macrophage-lymphocyte cultures. The quantity and type (I or II) of interferon, as well as the magnitude of the transformation response, is affected by the type of cell culture used for assay. The kinetics of lymphocyte reactivity in doners studied within 12 weeks after disease were compared to those occurring at greater than 12 weeks after disease and in seronegative donors. The observed kinetics were variable according to the methods used to prepare mononuclear cells for culture.

Antibody Formation↗
PubMedDate not supplied

Porphyrin rings and phospholipids: stimulators of cloning efficiency in certain species of Tetrahymena.

Species of Tetrahymena, including T. vorax, T. thermophila, T. pyriformis, and T. pigmentosa, were tested for cloning efficiency in proteose peptone and in synthetic nutrient media to which were added hemin, protoporphyrin IX, chlorophyllin, or asolectin, an impure mixture of phospholipids. All species could be cloned with high efficiency in the crude media. In unsupplemented synthetic medium the cloning efficiencies were 0-10%, around 50%, around 50%, and 90-100% for T. thermophila, T. vorax, T. pyriformis, and T. pigmentosa, respectively. The first three were all stimulated to 90-100% by addition of the porphyrin or phospholipid compounds mentioned above. Uroporphyrin III and coproporphyrin I and III had no effect. We suggest that cells unable to form clones suffer from a lack of cellular energy. This situation may be alleviated by our additions, certain porphyrin rings may be built into cytochromes and phospholipids may be used as fuel. Thus, the synthetic media used so far for these ciliates have not been optimal.

Animals↗
PubMedDate not supplied

Survival of Tetrahymena thermophila at low initial cell densities. Effects of lipids and long-chain alcohols.

Cells of the ciliate Tetrahymena thermophila failed to establish cultures in lipid-free standard synthetic nutrient medium if the initial population density was 250 cells per ml or less. These cells died within 10 h, but were saved and formed dense cultures if their medium was supplemented with 10 micrograms per ml of either certain phospholipids, 1,2-di-, 1-monoglycerides, fatty acids, long-chain alcohols, or sterols. Cell multiplication was followed in cultures in which the standard synthetic medium was supplemented with a selection of the compounds listed above. It was observed that the cells in the supplemented cultures in their exponential phases of growth had about the same average doubling times as control cells starting multiplication at 10-fold higher initial cell densities in lipid-free medium. These cells have been grown for decades in lipid-free synthetic nutrient media at short (ca. two-three h) doubling times. Therefore lipids have been considered nutritionally non-essential for growth and multiplication of these cells. We propose that those compounds that rescue the cells at low cell densities act as "proliferation signals," sensu lato. This effect of lipids and long-chain alcohols has so far remained unnoticed.

Alcohols↗
PubMedDate not supplied

Infantile hypertrophic pyloric stenosis and subsequent ulcer dyspepsia. A follow-up study of medically and surgically treated patients.

Infantile hypertrophic pyloric stenosis was treated in 324 cases in 1950-1966. At follow-up 19-35 years later, 296 of the patients could be traced, and 284 replied to a questionnaire concerning ulcer dyspepsia. Among the 80 patients who had been medically treated for pyloric stenosis, the prevalence of ulcer dyspepsia was 13.8%, and in the 204 surgically treated patients it was 9.3%. The difference was not statistically significant.

Adult↗