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Biomedical subjects

K Kjeldsen

Publications and source records attributed to K Kjeldsen.

At least 145 records · Page 8Linked to original sources
PubMed1975

Moderate hypoxia exposure and fetal development.

Exposure of rabbits to 15.5% oxygen during pregnancy resulted in a 17% decrease of birth weight and a neonatal mortality of 19% as opposed to 1% in the control groups, just corresponding to the effects obtained previously by moderate exposure of pregnant rabbits to carbon monoxide. Since additive effects of hypoxia exposure and carbon monoxide exposure are supposed to occur, it is concluded that women living at a high altitude should be warned particularly about the risk of delivering small babies if they have been smoking during their pregnancy.

Animals↗
PubMed1975

Aortic intimal injury in rabbits. An evaluation of a threshold limit.

Sixty-one rabbits were exposed to carbon monoxide, and aortae were then examined by light microscopy and transmission and scanning electron microscopy. The CO concentration in ambient air and the exposure time were varied to estimate the threshold limit for CO-induced focal intimal edema. A significantly higher incidence (P less than .0001) of focal intimal changes was present in rabbits exposed to 180 ppm of CO for four hours or more than in rabbits given a shorter or weaker exposure. The present study, as well as recent reports on the effect of low-level CO exposure on the cardiovascular system, suggests that the CO content in tobacco smoke and in heavily polluted atmospheric air may be deleterious to the arterial wall and enhance atherogenesis. A reevaluation of the recommended threshold limit for industrial CO exposure is proposed.

Animals↗
PubMed1975

Intimal ultrastructure of human umbilical arteries. Observations on arteries from newborn children of smoking and nonsmoking mothers.

The umbilical artery was chosen as a possible model for evaluating the vascular injury provoked by tobacco smoking in humans. Cords from newborn children delivered by 15 nonsmoking and 13 smoking mothers were studied in the transmission and the scanning electron microscope. Pronounced intimal changes were seen in the arteries from smoking mothers; the most important findings were degenerative changes of the endothelium such as swelling, blebbing, contraction, and subsequent opening of the endothelial junctions with formation of subendothelial edema. Other observations included dilation of the endoplasmic reticulum in the endothelium and reparative changes such as a considerable widening of the basement membrane. Since similar changes can be induced in arteries of animals by exposure to carbon monoxide or perfusion with nicotine, we conclude that the present study supports the concept that tobacco smoking is harmful to the vascular endothelium. This study also contributes to an understanding of the mechanism through which vascular injury is provoked in heavy smokers.

Adolescent↗
PubMed1975

Evaluation of the impact of various diseases on mortality.

The scarcity of resources within the health sector creates serious allocation problems. If it were legitimate to allocate the available means to the various diseases according to their impact on the length of human life, how should this impact be evaluated? That is the purpose of this study, which compares and evaluates methods for measuring the importance of various diseases from the point of view of their lethal effects and significance for life expectancy.THREE METHODS OF EVALUATION HAVE BEEN USED: the percentage of all deaths due to the disease (method A); the gain in life expectancy that would occur if the disease were eradicated as a cause of death (method B); and the change in the ratio between productive and nonproductive groups that would result from eliminating the disease as a cause of death (method C). The analyses are based on the total number of deaths in Denmark in 1969 and 1971. According to (A), one-third of all deaths was caused by heart diseases, one-fourth by cancer, and one-tenth by stroke. The results of method (B) were in agreement with those of method (A); the greatest gain in life expectancy was obtained by eliminating cardiac diseases; cancer ranked second, and accidents third for men and fourth for women. Method (C) yielded contrasting results. The result of eliminating most diseases would be a decrease in the proportion of persons of productive age. This was most distinct for cardiac diseases. The most important exception to this rule was accidents: if these were eliminated, the distribution of the population in the productive and nonproductive age groups would remain stable.

Adolescent↗
PubMed1973

Association between atherosclerotic diseases and carboxyhaemoglobin levels in tobacco smokers.

In a cross-sectional study carboxyhaemoglobin (COHb) levels in tobacco smokers were found to provide a better indication of a person's risk of having developed certain atherosclerotic diseases, including ischaemic heart disease, than the smoking history. In the age group 30-69 years a person with a COHb level of 5% or more was found to be 21 times (lower 95% confidence limit 3.3 times) as likely to be affected by these diseases as another person of the same age and sex with similar smoking history and current smoking habits but with a COHb level of less than 3%.

Age Factors↗