Sex differences in lung vulnerability to tobacco smoking.

Studies have indicated that females are more vulnerable to the deleterious effect of tobacco smoking than males. The current study aimed to investigate the associations between tobacco smoking and reported respiratory symptoms, self-rated health, and lung function by sex. In 1995-1997 65,225 subjects aged > or = 20 yrs (71% of invited) attended for screening within the Nord-Tr?ndelag Health Study. Among these, 10,941 subjects selected randomly or because they reported having asthma or asthma-related symptoms, participated in the Bronchial Obstruction in Nord-Tr?ndelag study consisting of spirometry and a personal interview. Tobacco smoking was associated with increased prevalence of respiratory symptoms, reduced lung function, and lower score on global self-rated health (SRH). Adjusted for smoking burden and lung function, females had a higher risk for reporting respiratory symptoms and lower SRH compared with males. Further, smoking burden was associated with a larger relative reduction in expiratory lung function in females than in males. Females reported more symptoms and lower self-rated health compared with males with similar smoking burden. Even if smoking in females was associated with a larger reduction in per cent predicted lung function compared with males, this does not fully explain the higher symptom prevalence in females.     

Transtracheal Doppler: a new procedure for continuous cardiac output measurement

An endotracheal tube with a 5 mm diameter ultrasonic transducer incorporated into its distal end was inserted into the tracheas of six anesthetized dogs. The device provides for ultrasound measurement of aortic diameter and blood velocity in the ascending aorta to obtain cardiac outputs. Because measurements are made proximal to the origins of the aortic arch vessels, total cardiac output is obtained. Procedures for measurement of aortic diameter, aortic blood velocity, and cardiac output are discussed. The resulting data were used to empirically determine the angle of incidence of the ultrasound beam that gave the best least squares fit over a range of thermodilution cardiac outputs. For an angle of incidence of 62.3 degrees, the relationship between cardiac output determined by thermal dilution and by transtracheal Doppler was transtracheal Doppler cardiac output = -.69 + 1.19 thermal dilution cardiac output. R2 = .82. The results from this preliminary assessment of the feasibility of measuring cardiac output in dogs using transtracheal Doppler suggest that additional studies should be pursued. Additional issues that require investigation include confirmation of constancy of human anatomy and demonstration of lack of tracheal trauma from the Doppler equipped endotracheal tube.     

Magnetic resonance imaging: absence of in vitro cytogenetic damage

Human lymphocytes and Chinese hamster ovary (CHO) cells in culture were exposed for 12 1/2 hours to a magnetic resonance imaging apparatus with a 2.35-Tesla magnet and 100-MHz radio frequency emission. The cells were examined for cytogenetic damage manifested either as chromosome aberrations or sister chromatid exchanges (SCEs), which constitute very sensitive measures of genetic and cellular damage. In either unstimulated or stimulated human lymphocytes, as well as in exponentially growing CHO cells, no increase in either chromosome aberrations or SCEs was found as a result of exposure to these MR conditions. The data indicate that long-term exposure to MR imaging conditions far exceeding those to be found in the clinical situation does not cause cytogenetic damage.     

Visual Impairment Related to Cognition and Loneliness in Old Age

Reported problems in visual acuity were examined as determinants of loneliness experienced by community dwelling people with either impaired or unimpaired cognition. The Mini-Mental State Examination (MMSE) was used as a screening instrument to form a cognitively-impaired (MMSE 20–23/30) and a cognitively-intact group (MMSE 28–30/30). A total of 147 subjects took part in the study and were examined by an optometrist. Subjects with intact cognition tended to report visual problems more often than subjects with cognitive deficits. One out of two subjects had slight visual impairment, in both cognitive groups. After acuity had been optimally corrected, six to seven out of ten subjects' visual acuity did improve. In a multiple regression analysis, higher MMSE score and visual improvement were significantly related to lower levels of self-reported loneliness among the elderly with their cognition intact, but not among the subjects with impaired cognition.