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Biomedical subjects

M Johansen

Publications and source records attributed to M Johansen.

42 records · Page 3Linked to original sources
PubMed1982

Sister chromatid exchange frequency in human epidermal cells in culture treated with 8-methoxypsoralen and long-wave UV radiation.

The effects of 8-methoxypsoralen with long-wave ultraviolet radiation on the sister chromatid exchange frequency in human epidermal cells in culture was investigated. With a constant amount of radiation the number of exchanges increased in an approximately linear manner with increasing concentrations of 8-methoxypsoralen up to 0.3 micrograms/ml. Above this concentration there were fewer dividing cells and an apparent departure from linearity in the dose-response curve. These results show that 8-methoxypsoralen concentrations equivalent to those found in the serum of patients undergoing photochemotherapy, in conjunction with UVA radiation, cause striking increases in sister chromatid exchange frequency in human epidermal cells in vitro.

Aged↗
PubMed1980

Prodrugs as drug delivery systems IV: N-Mannich bases as potential novel prodrugs for amides, ureides, amines, and other NH-acidic compounds.

The hydrolysis kinetics of a series of N-Mannich bases of carboxamides, thioamides, and other NH-acidic compounds were studied to assess their suitability as prodrugs for various drugs. The pH-rate profiles for the compounds were determined at 37 degrees and were accounted for by assuming the spontaneous decomposition of both free and protonated Mannich bases. The reaction rate for the free base increased sharply with increasing steric effects of the amine component of the N-Mannich bases and also with increasing acidity of the amide component. N-Mannich bases may be potentially useful prodrugs for NH-acidic compounds such as various amides, and ureides and for amines.

Amides↗
PubMed1980

Plasma erythropoietin levels in mice during the growth period.

Plasma erythropoietin (erythropoiesis stimulating factor(s), ESF), PCV and body weight were measured in normal mice from birth until the age of 70 d. Low but detectable ESF activity was present at birth, following by undetectable levels 12-48 h after birth. Thereafter the ESF level rapidly increased. Peak levels were obtained 15-20 d after birth. During the same phase an increased growth velocity occurred, coincident with decreased PCV levels. A fall to undetectable levels in plasma ESF activity coincided with decelleration of growth 40-50 d after birth. In small litters (four pups per litter) growth velocity and PCV levels were significantly higher than in large litters (16 pups per litter) 8 and 15 d after birth. The plasma ESF activity, however, did not differ between the two groups. Prohibiting suckling for a period of 16 h did not change the plasma ESF level. The hypothesis is put forward that growth directly or indirectly stimulates ESF production.

Animals↗
PubMedDate not supplied

Microcomputer education for nursing: an approach to microcomputer education in a large tertiary care center.

Communication skills needed for the healthcare environment are changing. In the past, poor reading and writing skills made it difficult to use a paper chart. Current computer technology provides many new opportunities for communicating in the clinical setting. Computer literacy has become a necessary skill for efficient use of clinical computer systems. At this large tertiary care setting, a survey was developed and distributed to staff to assess learner needs. Nursing staff identified educational needs for basic computer knowledge, the ability to move between computer functions, and the skills to navigate through specific applications. Based on survey analysis, three educational classes were constructed that addressed the department's specific needs.

Attitude of Health Personnel↗
PubMedDate not supplied

A genetic approach to the aetiology of giant cell arteritis: depletion of the CD8+ T-lymphocyte subset in relatives of patients with polymyalgia rheumatica and arteritis temporalis.

OBJECTIVE: To investigate the CD8+ T-cell concentrations in first degree relatives of patients with giant cell arteritis (GCA) in order to evaluate whether the low CD8+ T-cell values found in most patients with GCA are acquired or hereditary. METHODS: Probands were 5 patients with arteritis temporalis (TA) and 15 with polymyalgia rheumatica (PMR). Forty of 60 available relatives participated in the study. They were all interviewed concerning signs of previous illness. A blood sample screening was performed, including IgM-RF and ANA on Hep-2 cells. Age- and sex-matched controls consisted of 29 persons with no history of inflammatory or malignant diseases. Measurements of the T-lymphocyte subsets CD3+, CD4+ and CD8+ were made after Ficoll-Hypaque separation. RESULTS: Healthy relatives disclosed a significantly decreased CD8+ percentage in their peripheral blood compared with controls. The median CD8+% in relatives was 17% (C1 95% 15-20%) and in controls it was 23% (C1 95% 20-28%). Twelve relatives had a decreased concentration of CD8+ T-cells and 10 showed an elevated CD4+/CD8+ ratio. Two relatives had GCA and 3 had rheumatoid arthritis (RA). In one family 3 healthy siblings participated and showed extremely low CD8+ percentages (2.5%, 6.5%, 3.4%) and absolute values (0.042, 0.102, 0.035 x 10(9)/l) CONCLUSION: TA, PMR and RA are frequently (12.5%) found in the first degree relatives of patients with GCA. The finding of extremely low CD8+ T-cell values in completely healthy relatives indicates that the CD8+ T-cell depletion seen in patients with GCA is a hereditary characteristic.

Antibodies, Antinuclear↗