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Biomedical subjects

B Nielsen

Publications and source records attributed to B Nielsen.

At least 289 records · Page 16Linked to original sources
PubMed1984

Adenomyoepithelial adenosis and low-grade malignant adenomyoepithelioma of the breast.

Adenomyoepithelial adenosis of the breast is a form of adenosis not previously described. It is similar in several ways to microglandular adenosis, but one significant difference is the presence of myoepithelial cells. The present case originated as adenomyoepithelial adenosis in a 46-year-old woman. In the course of 18 years it proliferated and changed into a low-grade malignant adenomyoepithelioma. Electron microscopy confirmed the presence of myoepithelial cells in the adenosis, and immuno-histochemical study demonstrated cells containing actin (representing myoepithelial cells) in the adenosis as well as in the adenomyoepithelioma.

Adenocarcinoma↗
PubMed1984

Influence of skin temperature distribution on thermal sensation in a cool environment.

Thermal sensation and distribution of skin temperatures in persons exercising at 36.5 W on a bicycle ergometer and resting in a cool environment (10 degrees C) in two different clothings, one with the insulation mainly over the trunk (1.22 clo), and one with well insulated limbs (1.67 clo), were studied. Their general thermal sensations varied from slightly warm to slightly cool. The placing of the insulation had a decisive influence on skin temperature distribution, so that skin temperature was always high in well-insulated areas. When the insulation was placed over the limbs, a greater amount of heat was lost than if a similar insulation was placed on the trunk. Neither Tsk nor skin temperature distribution correlated with general thermal sensation. Instead, mean body temperature seemed to be the determinant of general thermal sensation in these conditions. The best prediction of general thermal sensation was obtained by adding Tre with a weighting factor of 0.8-0.9 and Tsk with a weighting factor of 0.1-0.2.

Adolescent↗
PubMed1984

Measurement of mean skin temperature of clothed persons in cool environments.

The precision with which mean skin temperature could be estimated from some few points on clothed persons in a cool environment was studied. The skin temperature data were obtained from experiments on 10 clothed persons who were resting and working at an environmental temperature of 10 degrees C. With these data, eleven calculation formulas in current use were compared to a "reference mean skin temperature" based on a weighting formula involving 13 local skin temperatures. It was concluded that no formula including less than seven points gave a reasonably accurate mean skin temperature in this cool environment. In addition, a stepwise correlation analysis involving linear regression was performed on the data. This gave 12 new calculation formulas, which were evaluated for accuracy in estimating mean skin temperature. Among these, a weighting formula involving only four local skin temperatures was selected to be recommended for use in field investigations: Tsk = 9.429 + 0.137 X Tforehead + 0.102 X Thand + 0.290 X Tlower back + 0.173 X Tlower leg.

Adolescent↗
PubMed1984

Cardiovascular responses to heat stress and blood volume displacements during exercise in man.

Subjects exercised in the upright position at approximately 50% of maximal oxygen consumption in four situations: in 25 degrees C air, in 45 degrees C air [mean skin temperature (Tsk) 35 degrees C], in 35 degrees C water immersed to the level of the xiphoid process, and finally wearing a suit perfused with 35 degrees C water. The water immersion prevented gravitational shifts of blood volume to the legs. In this situation the forearm blood flow (FBF) rose continually with increasing core temperature (Tes) in contrast to the attenuation in rise above 38 degrees C Tes in 45 degrees C air. The differences were significant above 38.6 degrees C Tes in experiments in eight subjects. The effects of immersion on cardiac output (CO), stroke volume (SV), and heart rate (HR) were studied in five of the subjects in relation to Tes, since the rate of rise of Tes was different in the four situations. CO and SV tended to be higher during both rest and exercise in the water than in the other three conditions, while HR rose in the same manner with increasing core temperature, except that it was lower in 25 degrees C air, where Tsk was lower. Thus, the prevention of hydrostatic shifts of peripheral venous volume permitted the maintenance of a higher SV and peripheral blood flow, and enhanced the ability of the circulation to deal with the combined exercise and heat stress.

Adolescent↗
PubMed1984

Cardiovascular, hormonal and body fluid changes during prolonged exercise.

During prolonged heavy exercise a gradual upward drift in heart rate (HR) is seen after the first 100 min of exercise. This "secondary rise" might be caused by a reduction in stroke volume due to reduced filling of the heart, which is dependent upon both hemodynamic pressure and blood volume. Swimming and bicycling differ with respect to hydrostatic pressure and to water loss, due to sweating. Five subjects were studied during 90 min of bicycle exercise, and swimming the leg kick of free style. The horizontal position during swimming resulted in a larger cardiac output and stroke volume. After the initial rise in heart rate the "secondary rise" followed parallel courses in the two situations. The rises were positively related to the measured increments in plasma catecholamine concentrations, which continued to increase as exercise progressed. The secondary rise in HR could not be explained by changes in plasma volume or in water balance, nor by changes in plasma [K]. The plasma volume decreased 5-6% (225-250 ml) within the first 5 to 10 min of exercise both in bicycling and swimming, but thereafter remained virtually unchanged. The sweat loss during bicycling was four times greater than during swimming; but during swimming the hydrostatic conditions induced a diuresis, so that the total water loss was only 25% less than during bicycling.

Adult↗
PubMed1984

Energy imparted to fluorescent screens from primary and scattered radiation. Variations with atomic composition and screen thickness.

The effects of thickness and atomic composition of fluorescent screens on the impartation of primary and scattered radiation is analysed. Different fluorescent screens give rise to different quotients epsilon p/epsilon s of energy imparted from primary and scattered radiation respectively, due to their variation in atomic composition and thickness. The image contrast in a given radiation field therefore varies with the choice of screen. Energy imparted by primary and scattered radiation in different fluorescent screens has been calculated as a function of tube voltage using a simple analytical model. Comparison of the results for fluorescent screens of different thicknesses with hypothetical screens with both negligible and total absorption has been made. From the results it is evident that the image contrast increases with increased detector thickness if scattered radiation is present. The trends found in the calculations have been confirmed by measurements of the energy imparted from scattered and primary radiation for a number of fluorescent screens including both commercial and specially made screens. Differences in the ratio epsilon p/epsilon s of up to 50% have been measured, and differences reported by other authors are discussed. Their use of detectors with different response to scattered and primary radiation may explain the discrepancies found.

Calcium Compounds↗
PubMed1984

Classification of patients with myelodysplastic syndromes according to the FAB co-operative group's proposals. Proposals for a redefinition of blast cell type II.

53 patients with the myelodysplastic syndromes (MDS) were classified according to the proposals of the FAB cooperative group 1982. 29 patients had refractory anaemia (RA), 10 refractory anaemia with excess of blasts ( RAEB ), 5 RAEB in transformation, 7 RA with ringed sideroblasts and 2 chronic myelomonocytic leukaemia ( CMML ). Counting blast cells type I and II involved no difficulties. 4 of 15 patients who developed acute myeloid leukaemia (AML) according to the FAB classification of 1976 did not fulfill the new 1982 criteria for AML. A redefinition of the blast cell type II to include a more granulated blast cells, without the characteristics of promyelocytes, would solve this problem. We conclude that a redefinition of the blast cell type II might turn out to be useful.

Adult↗
PubMed1984

Measurement of background signals due to scattered and off-focal radiation on CT scanners.

The magnitude of scattered and off-focal radiation in relation to the primary radiation has been measured for 4 commercial CT scanners of third generation (only rotation). The measurement has been done by placing a lead beam stop in front of a scattering phantom as well as without a phantom and registering the detector signal behind and outside the lead beam stop. The off-focal radiation has been found to be very similar in magnitude for 3 of the scanners compared, while the scattered radiation from the phantom was found to vary with parameters like distance between phantom and detector, grid in front of the detector and self collimation of the detector.

Background Radiation↗