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Biomedical subjects

P Kolari

Publications and source records attributed to P Kolari.

11 recordsLinked to original sources
PubMed2001

Continuous mean arterial pressure measurement in the fingers: the influence of local arm cooling.

Two different methods were studied for non-invasive beat-to-beat finger mean arterial pressure (MAP) measurement in 14 healthy volunteers during local arm cooling to 17 degrees C. Fingertip skin blood flow was recorded by a laser Doppler instrument. The difference between the oscillometric beat-to-beat blood pressure measurement device (UT9201) and volume clamp monitor (Finapres) before cooling was -1.5+/-1.1 mmHg, and, although statistically significant, (p< 0.01), this difference cannot be considered clinically meaningful. The results obtained using the two devices during arm cooling showed a systematic disagreement in the continuously recorded MAP. After a 30s period of cooling, the group-averaged difference of UT9201 minus Finapres, calculated as change from the baseline, reached (mean +/- SD) 8.8+/-6.3 mmHg (statistically significant, p< 0.01).

Adult↗
PubMed1994

Evaluation of a decision-support system for inoperable non-small cell lung cancer.

The purpose of this study was to find out whether a decision-support system is able to assist a clinician in predicting patient outcome and in selecting optimal treatment in oncology. The domain of the evaluated decision-support prototype was primary therapeutic decision making in inoperable non-small cell lung cancer. The performance of the prototype was tested on retrospective material consisting of 112 patients treated by radiotherapy. Survival was the endpoint for examining whether the treatment decision proposed by the system was more accurate than the decision actually made by the clinician. Certain prognostic variables were used by the system to classify patients into two treatment groups, radical or palliative radiotherapy. The median survival times of these groups were 15 and 7 months, respectively, compared with 9 and 8 months in the corresponding groups classified by the clinician. Our results indicate that clinicians need support in treatment selection and that decision-support systems could be a potential answer.

Carcinoma, Non-Small-Cell Lung↗
PubMed1993

Circadian variation in peripheral blood flow in relation to core temperature at rest.

The aim of the present study was to examine the circadian variation in skin blood flow and its relationship to the rhythm of rectal temperature. Eight young men were confined to continuous bed rest for 24 h in a thermoneutral environment. Rectal temperature, oxygen consumption, and peripheral blood flow (laser-Doppler flowmetry and plethysmography) were measured at intervals of 2 h, except at 2400 hours and 0600 hours. According to the cosinor-method, the mean rectal temperature displayed a statistically significant circadian variation with a minimum at 0400 hours. A significant circadian rhythm was also observed in total finger blood flow, finger laser-Doppler flow, and forearm laser-Doppler flow, but not in total forearm blood flow and forehead laser-Doppler flow. The rhythms of rectal temperature and extremity skin blood flow were phased differently, i.e. the decrease in rectal temperature was preceded by an increase in extremity skin blood flow with an average of 4-h time difference. The results would support the idea that circadian rhythm of core temperature is, at least in part, regulated by variation in extremity skin blood flow.

Adult↗
PubMed1992

Solar ultraviolet (UV) radiation and UV doses received by patients during four-week climate therapy periods in the Canary Islands.

The ultraviolet (UV) radiation doses received by 270 psoriasis patients were studied during 4-week climate therapy periods in November, March or April in the Canary Islands. The daily total solar UV radiation (ambient radiation load, ARL) was measured using frequent readings with a Robertson-Berger sunburning ultraviolet (SUV) meter. A daily personal radiation load (PRL) was calculated for each patient, using sun exposure diary data. To measure the cumulative UV exposure of particular skin sites (skin site dose, SSD), 10 patients wore polysulphone UV dosimeters. The daily ambient radiation load (ARL) ranged from 2.9 to 8.9 erythemal units (EU); the cumulative ARL for a 4-week treatment period was 182.6 EU. The mean daily personal radiation load (PRL), calculated separately for each week of the treatment period, was from 2.5 to 5.6 EU; the mean total 4-week PRL was 118.0 EU, being about 65% of the ARL. The 4-week cumulative skin site dose (SSD) varied between 22.2 and 63.3% (mean 41.2%) of the corresponding personal radiation load (PRL).

Adolescent↗
PubMed1989

A non-invasive method for testing neural circulatory control in man.

Exaggerated cardiovascular responsiveness is common in young men and may cause non-specific symptoms and poor performance. Conventional autonomic function tests are not clinically useful. We have therefore designed a thermal entrainment method to evaluate sympathetic and parasympathetic cardiovascular function in subjects with dystonic symptoms and orthostatic intolerance. Oscillations of thermal gradient in the skin were produced by standardised periodic stimulation of the lower part of the arm with warm and cool water. Vasomotor activity of the skin induced oscillations of arterial blood pressure which were thought to be regulated by sympathetic and parasympathetic heart rate control and by oscillation of the sympathetically controlled peripheral vascular resistance. We tested the method in subjects with cardiovascular symptoms (n = 7) and controls (n = 7). At supine rest, the frequency response of the heart rate variability to the thermal stimulation at frequencies of 0.01, 0.02, 0.03 and 0.1 Hz was significantly different (p = 0.008) between symptomatic subjects and controls. The gain of the heart rate control was increased to 0.03 Hz [-1.3(SEM 0.5) dB v -3.8(0.8) dB, p = 0.068] and decreased at 0.1 Hz [-3.9(1.1) dB v -1.5(0.6) dB, p = 0.076] in the test group compared to the control group. At stimulus frequencies of less than 0.03 Hz the individual overall heart rate variability of the subjects with symptoms stayed below the mean control value, at 60(6) ms v 79(15) ms, p = 0.16. The cutaneous temperature oscillations at the site of stimulation, frequency response of the oscillations of the skin blood flow and respiration to the thermal stimulation, and mean heart rate were similar in the both groups. The results show that this thermal entrainment method quantifies the increased sympathetic and decreased parasympathetic cardiac control of subjects with dystonic symptoms.

Adult↗
PubMed1987

Skin blood flow during incremental exercise in a thermoneutral and a hot dry environment.

Eight physically fit men performed two incremental bicycle ergometer tests, one in an ambient temperature of 25 degrees C and the other at 40 degrees C. Oesophageal temperature (Tes) increased continuously throughout the tests up to 38.0 and 38.3 degrees C, respectively. In both environments, forearm blood flow (plethysmography) was linearly related to Tes above the Tes threshold for vasodilation, but at the heaviest work loads this relationship was clearly attenuated and therefore indicated skin vasoconstriction, which tended to be more pronounced at 25 degrees C. During recovery at 25 degrees C, in some subjects the forearm blood flow increased above the levels observed at the end of the graded exercise in spite of a decreasing Tes. Skin blood flow, measured by laser Doppler flow meter at the shoulder, was quantitatively different but, on average, seemed to reveal the same response pattern as the forearm blood flow. In spite of the higher level of skin blood flow in the heat, blood lactate accumulation did not differ between the two environments. The present results suggest that there is competition between skin vasoconstriction and vasodilation at heavy work rates, the former having precedence in a thermoneutral environment to increase muscle perfusion. During short-term graded exercise in a hot environment, skin vasoconstriction with other circulatory adjustments seems to be able to maintain adequate muscle perfusion at heavy work levels, but probably not during maximum exercise.

Adult↗
PubMed1986

Aerobic and anaerobic responses to incremental exercise in a thermoneutral and a hot dry environment.

In an investigation of the effect of acute heat exposure on aerobic and anaerobic metabolism, eight unacclimated men performed two incremental bicycle ergometer tests in random order, once under thermoneutral conditions (25 degrees C) and once in a hot dry (40 degrees C) environment. Oxygen consumption (VO2) and pulmonary ventilation were measured every minute. Fingertip blood samples were taken at each work level for blood lactate (LA) determination. Compared to the results at 25 degrees C, the mean VO2 was significantly (P less than 0.01) lower during exercise at 40 degrees C. In the hot dry environment the blood lactate threshold was slightly reduced in four subjects, but neither the average peak nor the post-exercise blood LA values differed from the findings at 25 degrees C. During the exercise-heat stress, the ventilatory threshold did not change significantly. The results indicated that, during relatively short-term incremental exercise in a hot environment, almost adequate muscle metabolism can be maintained.

Adult↗
PubMed1986

Finger peripheral resistance during local cold provocation in vasospastic disease.

Finger systolic blood pressure (FSBP), finger arterial inflow (FAI), finger venous opening pressure (FVOP), and finger peripheral resistance (FPR) were evaluated in 56 workers exposed to chain-saw vibration. Twenty-one of the workers were free from vibration-induced white finger (VWF). In 17 subjects VWF had ceased; 12 of the subjects had active VWF; 6 subjects had Raynaud's disease. The subjects were examined in a supine position under thermoneutral conditions with strain-gauge plethysmography. Cold provocation of the finger caused a significant reduction in FSBP in the groups with Raynaud's disease and active VWF. The finger circulation of the subjects with active VWF and that of those with Raynaud's disease showed a significantly reduced FAI when compared with that of the symptom-free referents. Finger cooling produced a gradual reduction in the FVOP and a significantly increased FPR of the subjects with active VWF and in those with Raynaud's disease. FPR was already increased in the Raynaud's disease group at the beginning of the test, whereas it increased in the VWF group as the temperature fell. The results suggest that in Raynaud's disease the fault is in the level of activity of the sympathetic outflow and in VWF it is peripheral mechanisms controlling the vessel tone.

Cold Temperature↗
PubMed1986

Vasomotor oscillation in vibration-induced white finger.

Vasomotor oscillation at different ambient temperatures, with and without anesthesia of the finger nerves, was studied in six persons with vibration-induced white finger (VWF) and in 10 referents. The power spectral density (PSD) of the Fourier transform of the laser-Doppler flowmeter signal from the finger pad vessels was analyzed. In both groups, the PSD of the vasomotor oscillation in the frequency range of 0.05-0.25 Hz was more pronounced in a cold than in a hot environment. Without finger nerve anesthesia, the oscillations of the referents were significantly greater (p less than 0.01) than those of the VWF subjects (PSD -34.4 dB and -41.6 dB, respectively). With anesthesia of the finger vasomotor nerves, the PSD was reduced in both groups. In the anesthetized finger there was no statistically significant group difference. Thus the myogenic component of the vasomotor activity was the same in the referents as in the VWF subjects. The results show that the autonomic neural influence on vasomotor oscillation in skin of the finger pad is weaker in persons with VWF. This weakness may be a sign of peripheral neuropathy, which may lead to a denervation syndrome causing hypersensitivity of the adrenoceptors to cold.

Adult↗
PubMed1985

Laser-Doppler and plethysmographic skin blood flow during exercise and during acute heat stress in the sauna.

Forearm skin blood flow was measured in six male subjects by laser-Doppler flowmetry (LDF) and venous occlusion plethysmography (VOP) during constant-load (125-200 W) upright bicycle exercise in a warm environment (X + SD, ta 34.6 +/- 0.2 degrees C) and during a 15 min sauna bath (ta 69.0 +/- 2.8 degrees C). During the sauna test the LDF values correlated well with the VOP measurements in the initial phase of active cutaneous vasodilation, after which the LDF values almost leveled off in spite of a steady increase in VOP measurements. During the exercise the mean VOP and LDF values rose in parallel with each other to steady state levels. The relationship between the results of the two methods proved to be nonlinear. It was concluded that different parameters were measured by VOP and LDF. The latter measured mainly the integrated velocity of blood flow in the outermost cutaneous tissue, and this velocity seemed to be partly dependent on the level of the arterial inflow (VOP), but also on the prevailing pressure-flow and pressure-volume relations in the cutaneous vascular bed.

Adult↗