PubMed Health⌕ Search

Biomedical subjects

D J Haumschild

Publications and source records attributed to D J Haumschild.

7 recordsLinked to original sources
PubMed1990

Changes in human skin blood flow by hyperthermia.

The heat-induced changes in blood circulation in human forearm skin were studied. With the use of laser Doppler flowmetry, it was possible to noninvasively monitor the velocity and volume of red cells, and thus the flow rate of red cells or blood flow in the human skin. When the skin surface was heated at 35 degrees -43 degrees C for 60 min, the laser Doppler flow (LDF) changed dynamically, indicating that the blood flow in human forearm skin could increase as much as 15-20 times during heating at 43 degrees C. Such an increase in laser Doppler flow resulted from dilation of arterioles and recruitment of capillaries, and also to a lesser extent, from an increase in the velocity of red cell flux. The increase in the velocity of red cell flux implies that arteriovenous anastomoses exist in the human forearm skin, in contradiction to the common view that human forearm skin is devoid of arteriovenous anastomosis.

Female↗
PubMed1989

Effects of temperature on blood circulation measured with the laser Doppler method.

The effects of local heating or cooling on skin microcirculation in volar aspect of human forearms was studied using laser Doppler flowmetry. When the skin was heated to 40 degrees C from a normal temperature of 32 degrees C, red cell flow (laser Doppler flow, blood flow) momentarily increased several fold and then temporarily decreased. The flow subsequently resumed a gradual increase reaching 10-15 times that of control in 30-40 min. When the skin temperature was returned to 32 degrees C after 60 min of heating, the blood flow momentarily declined but soon increased for several minutes before it began its major descent. When cooled from 32 degrees C to 5 degrees C, the flow momentarily decreased, but soon increased, surpassing the pre-cooling level. The flow began to decline when the cooling was prolonged for more than 15-20 min. The changes in flow corresponded well with the changes in number (volume) and speed of red cells. Laser Doppler flowmetry was found to be very useful for continuously monitoring microcirculatory blood flow in human skin.

Adult↗
PubMed1989

Influence of local and environmental temperatures on cutaneous circulation with use of laser Doppler flowmetry.

The purpose of this study was to determine a standard set of conditions for detecting peripheral arteriosclerosis with ischemia. One series of studies was done to determine the influence of room temperature on peripheral flow in healthy subjects and patients with peripheral vascular disease. The room temperature was varied from 30 degrees to 35 degrees C. The temperature from 24 degrees to 30 degrees C had only minor effects on the circulation. Thus, it seemed appropriate to use a room temperature in the lower range, usually 23 degrees C. Another series of studies showed the effect of changing skin temperatures locally at the finger tip or toe tip on the plantar and volar surfaces in healthy subjects and in patients with peripheral vascular disease. Results showed that as temperature was increased from 10 degrees to 45 degrees, there was a marked increase in the finger and toe circulations, which was considerably greater in the normal subjects as compared with those with digital disease. The ideal temperature at which to work as a routine is 40 degrees C as opposed to the lower temperatures, which did not separate healthy subjects from patients with peripheral vascular disease. A third experiment was done to study normal subjects and patients by using the finger circulation as control against the toe circulation when the conditions were a local skin temperature of 40 degrees C and a room temperature of 23 degrees C. A toe-finger index was established to detect abnormalities in the circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Evaluation of an infrared laser-Doppler blood flowmeter.

Several laser-Doppler blood flowmeters are now commercially available; however, only one utilizes an infrared laser diode (Laserflo, TSI, St. Paul, MN). Because of this and other unique features such as its microprocessor-based signal analyzer, we evaluated this device's ability to measure tissue perfusion. Initially, we determined whether laser illumination directly affected the microvasculature. Intravital microscopic observations in the hamster cremaster muscle indicated that neither He-Ne nor infrared laser light affected the diameters of arterioles that were responsive to vasoactive agents. To test the flowmeter for linearity and repeatability, we used a rotating disk to simulate a light-scattering, flowing medium. The "flow" signal was highly correlated (r = 0.99) with the rotational velocity of the disk, was consistent among flow probes, and showed a high degree of reproducibility. The second model consisted of microsphere suspensions pumped through cuvettes. The laser-Doppler velocimeter (LDV) flow signal was linear with respect to pump output. With red blood cells in the perfusate, we examined the effects of blood oxygenation on the flowmeter's performance. The LDV flow signal was unaffected by changes in blood oxygenation. We evaluated linearity in vivo in isolated, perfused rat livers and in isolated canine gastric flaps. We observed linear relationships between total flow and laser-Doppler flow measured on the surface of the liver (r = 0.98) and in the gastric mucosa (r = 0.98), but the slopes of the relationships between total and local LDV flow showed considerable variability not noted in the in vitro studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Clinical application of laser Doppler flowmetry for measurement of cutaneous circulation in health and disease.

The cutaneous laser Doppler device (LDF) was employed to determine its usefulness in differentiating the circulation of the feet in normal subjects from that in patients with arteriosclerosis obliterans. It is shown that the laser Doppler frequencies correlated well with results from venous occlusion plethysmography, which measured volume rate of flow. Thus, one can determine volume rate of flow by the simple Doppler method. There was a linear relationship between these two methods of measurements. Using the LDF method, it was determined that normal individuals have toe flows that on the average are 42% of finger flows in supine resting subjects. In peripheral vascular disease of the lower extremities, the LDF measurements showed a decreased circulation in the large toes when the patients are supine and the lower extremities flat. The results between health and disease are exaggerated by elevating the feet, at which time the diseased circulation falls to extremely low values compared with those of normal subjects. A similar decrease in skin oxygen tension in the diseased lower extremities was observed when the limbs were elevated.

Adult↗
PubMedDate not supplied

Continuous and non-invasive quantification of heat-induced changes in blood flow in the skin and RIF-1 tumour of mice by laser Doppler flowmetry.

The changes in blood flow in the skin and in the periphery of RIF-1 tumours of C3H mice could be monitored continuously during heating with the use of the laser doppler flowmetry. The laser probe was placed gently on the skin or tumour surface and the change in blood flow was quantified from the output signal from the monitor during the heating of the tissues with temperature-controlled water. The blood flow in the tumour increased significantly during the first 20-30 min of heating at 42.5-44.5 degrees C and then began to decline during the second half of one hour of heating. The skin blood flow either continuously increased or remained elevated during 1 h heating at 42.5-44.5 degrees C. These results were generally similar to the previous reports on the heat-induced changes in blood flow in the skin and tumours measured by other methods.

Animals↗