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Biomedical subjects

H Johansen

Publications and source records attributed to H Johansen.

At least 55 records · Page 3Linked to original sources
PubMed1983

Differential activation of the mouse beta-globin promoter by enhancers.

A series of plasmids was constructed to study the effect of two enhancers, the simian virus 40 72-base-pair repeat and the Harvey sarcoma virus 73-base-pair repeat, on the mouse beta maj-globin promoter. These plasmids contain the mouse beta maj-globin promoter linked to the Escherichia coli galK gene, thus allowing galactokinase enzyme activity to be used as a measure of promoter function. In CV-1 (primate) cells, it was found that an enhancer is required for optimal promoter activity and that the simian virus 40 (primate) enhancer increases galactokinase fourfold more than the Harvey sarcoma virus (mouse) enhancer. In L (mouse) cells, however, the Harvey sarcoma virus enhancer is 1.3-fold stronger than the simian virus 40 enhancer. These data support the hypothesis that enhancer activity can be species specific. Furthermore, when both enhancers are present on the same plasmid, their effect is additive on the beta-globin promoter whether the plasmid is in CV-1 cells or L cells.

Animals↗
PubMed1981

Selection of high risk groups among prognostically favorable patients with breast cancer.

In a prospective, nationwide, decentralized breast cancer project conducted by The Danish Breast Cancer Cooperative Group (DBCG) the recurrence rate within the first year after surgery was analysed in relation to tumor anaplasia. One thousand forty-eight patients met the requirements of eligibility, i.e. tumor size less than or equal to 5 cm with negative axillary nodes, and no skin or deep invasion. The recurrence rates in tumors with anaplasia Grades I, II, and III were 4, 9, and 14%, respectively (p = 0.001). Therefore, it seems possible, prospectively, among otherwise prognostically favorable patients, to select a group with high risk of recurrence which might benefit from adjuvant systemic therapy.

Anaplasia↗
PubMed1978

Solvent deposition method for enhancement of dissolution rate: importance of drug-to-excipient ratio.

Dissolution rates and particle sizes of phenylbutazone solvent deposited on lactose, starch, and silicon dioxide, separately, and of norethindrone and digoxin deposited on lactose were investigated. Microparticulate dispersed drugs on the surface of excipients result when drug-to-excipient ratios are low. Fast dissolution rates are observed for such systems. This effect can be extended to higher ratios when silicon dioxide is used as the excipient. Because of adsorption, however, the release from silicon dioxide is more or less limited.

Chemical Precipitation↗