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Biomedical subjects

I Olsen

Publications and source records attributed to I Olsen.

At least 253 records · Page 14Linked to original sources
PubMed1975

Thymidine kinase activity in human bone marrow cells.

The thymidine kinase activity per 10(6) DNA-synthesising marrow cells and the rate of incorporation of tritiated thymidine into the DNA of 10(3) DNA-synthesising marrow cells were estimated in 9 haematologically normal patients and 49 patients suffering from a variety of haematological disorders. Slight increases in thymidine kinase activity were found in 6 of the 31 patients with haematological diseases associated with normoblastic erythropoiesis and greater increases were found in 3 of the 18 patients with megaloblastic haemopoiesis due to vitamin B12 or folate deficiency. In the latter group, there was a statistically significant inverse correlation between haemoglobin levels and thymidine kinase activity. No correlation was found between thymidine kinase activity and the rate of incorporation of tritiated thymidine in either the normoblastic or megaloblastic group, suggesting that the level of thymidine kinase activity does not limit the rate of incorporation of exogenously supplied thymidine into the DNA of human bone marrow cells.

Anemia, Hypochromic↗
PubMed1975

Assessment of denture plaque pH in subjects with and without denture stomatitis.

To evaluate the "resting" pH and induced pH changes in denture plaque, soft deposits were collected from the fitting surface of the denture, pooled and suspended in water. Plaque pH was determined with microelectrode equipment before and after mouth rinsing with a sucrose solution. A characteristic level in the "resting" pH of denture plaque was found in most of 12 subjects tested. pH values below the baseline level were recorded for more than 2 h after a rinse. The pH depressions were more pronounced in maxillary than in mandibular plaque. Further, the pH minima tended to be lower in subjects with denture stomatitis than in controls. No clear relationship could be established between the "resting" pH and the concentration of Candida hyphae in denture smears or palatal inflammation.

Aged↗
PubMed1975

Denture stomatitis. Effects of chlorhexidine and amphotericin B on the mycotic flora.

In 100 patients with denture stomatitis cultures and direct smears were used to evaluate 5 treatments, including sucking of chlorhexidine, amphotericin B or placebo tablets combined with denture soaking in 0.2% chlorhexidine or water. After 14 days of treatment the amphotericin B lozenges had brought about a significant reduction in the quantity of fungus on the oral mucosa, whereas they barely affected the large amount present on the fitting surface of the upper denture. Denture immersion in chlorhexidine significantly reduced the number of organisms both on the mucous membrane and on the denture. It therefore seems at least as important to treat the denture as the patient in denture stomatitis. Fourteen days after withdrawal of the drugs the mycotic flora was largely re-established.

Amphotericin B↗
PubMed1975

Denture stomatitis. The clinical effects of chlorhexidine and amphotericin B.

The clinical effects of an antibacterial substance with antifungal activity (chlorhexidine) and specific antimycotic (amphotericin B) in denture stomatitis were studied in 100 patients. Five 14-day regimens of chlorhexidine, amphotericin B or placebo lozenges combined with denture immersion in 0.2% chlorhexidine or water were tested. The efficiency of amphotericin B and chlorhexidine was comparable. This indicates that chlorhexidine has a considerable antifungal effect in the oral cavity and, further, that fungi are the responsible micro-organism in denture stomatitis rather than bacteria. Chlorhexidine frequently discloured the dentures. A high incidence of local and general predisposing factors to denture stomatitis, as well as of relapse 14 days after treatment, was observed.

Amphotericin B↗
PubMed1975

Denture stomatitis. Relapse tendency and removal of acquired discolourations in long-term denture disinfection with chlorhexidine.

Five patients with denture stomatitis were initially treated for 14 days with a combination of amphotericin B lozenges and denture soaking in 0.2% chlorhexidine. To prevent recurrence the dentures were then kept overnight in 0.2% chlorhexidine during five months. No relapse occurred, but the dentures (all-acrylic) became heavily discoloured by chlorhexidine. During this period fungi could not be grown either on palatal or on maxillar denture agar models, and clinical signs and symptoms were reduced further. At the end of treatment hypochlorite was used to remove chlorhexidine-induced denture stain. Brushing and soaking (0.16%) proved more efficient than brushing alone, and when a 0.60% solution was used, the stains were generally eliminated in two hours. Hypochlorites in the prevention and removal of chlorhexidine discolourations deserve further attention.

Aged↗
PubMed1975

DNA synthesis in rabbit spleen explants. Its relationship to cell division.

The synthesis of DNA, as measured by the incorporation of [3H]-thymidine into the nuclei of cells of cultured explants of rabbit spleen, has been studied and correlated with estimation of DNA content of these nuclei using Feulgen densitometry, with and without colcemid arrest. Observations of the proportion of nuclei labelled with [3H]thymidine and their DNA content indicated that many cells were incorporating this precursor for DNA synthesis without the concomitant increases in DNA expected of cells in division cycle. Colcemid arrest failed to produce the changes in DNA content expected of a cell population as rapidly dividing as the labelling kinetics suggested. The results indicated that [3H]thymidine-labelled material, possibly DNA, was being transferred between cells and this accounted for the increased labelling index seen after pulsing with [3H]thymidine. The suppression of [3H]thymidine uptake by hydroxyurea indicated that this was not repair synthesis of damaged DNA.

Animals↗
PubMed1968

Identification of propionate as an endogenous CO2 acceptor in Rhodospirillum rubrum and properties of purified propionyl-coenzyme A carboxylase.

A heat-stable endogenous CO(2) acceptor has been found in extracts of Rhodospirillum rubrum grown photoheterotrophically on acetate. Evidence is presented which suggests that this factor is propionic acid. Thus, paper and gas chromatographic analyses have indicated that propionic acid is present in boiled extracts prepared from R. rubrum cells. The products of (14)CO(2) fixation obtained with either the boiled extract or propionic acid as the CO(2) acceptor were identical and were identified as methylmalonic acid and succinic acid by paper chromatography. The enzyme which catalyzes the carboxylation of propionyl-coenzyme A (propionyl-CoA carboxylase) was purified from R. rubrum cells grown on acetate and its properties were studied. The enzyme is similar to propionyl-CoA carboxylases isolated from mammalian sources.

Butyrates↗