Reflexes of the cutaneous microcirculation in amitriptyline and in fluoxetine treated patients.

Cutaneous microcirculation was investigated in 30 major depressed inpatients receiving either 150 mg amitriptyline (n = 15) or 30 mg fluoxetine (n = 15) as monotherapy, and in 15 normal control subjects matched for age and sex. The laser Doppler flux (LDF) was recorded while resting and under the condition of a sudden deep breath ("inspiratory gasp response"). In normal subjects this autonomic function test caused a marked decrement of LDF signal, which rapidly returned to the baseline value. In both groups of drug treated patients the decrements of LDF signal after a sudden deep breath did not differ from those found in the normal control subjects. However, in the amitriptyline-treated patients the return of LDF-signal to the baseline values was significantly delayed (P = 0.0007), while patients treated with fluoxetine showed the same behaviour as normal subjects. With a discriminant analysis using the results of the inspiratory gasp responses, 100% of the amitriptyline treated patients were correctly classified. Since both groups of depressed patients revealed comparable depression scores, the differences found are probably due to the side effects of amitriptyline. Possible clinical implications of these findings are discussed.

The effects of reboxetine on autonomic and cognitive functions in healthy volunteers.

RATIONALE: Though reboxetine, a selective noradrenaline reuptake inhibitor, causes autonomic and cognitive adverse events there is a paucity of appropriately designed studies on the cognitive and autonomic effects of the drug in the literature. OBJECTIVE: To compare the effects of reboxetine on cognitive and autonomic functions with those of placebo in healthy humans. METHOD: A randomised, double-blind, crossover study of 12 healthy male volunteers aged 25 (21-27; median, range) years. Subjects orally received 4 mg reboxetine and placebo twice daily for periods of 14 days each with at least 14 days in between. Vasoconstrictory response of cutaneous vessels (VR) and skin conductance response (SCR) following sudden deep breath were employed as parameters for autonomic function. Quantitative EEG (qEEG) and psychometric tests served as parameters for cognitive function. RESULTS: Reboxetine decreased SCR and prolonged the dilation phase of VR (P<0.05). It did not affect cognitive functions such as flicker fusion frequency, choice reaction, memory and psychomotor coordination but increased slow beta (beta1) power density in the qEEG. Tiredness (n=12), dry mouth (n=9), delayed urination (n=3) and constipation (n=1) were noted with reboxetine. CONCLUSION: Sustained peripheral and/or central sympathetic activation accounts for the prolongation of VR. The decrease of SCR and typical side effects suggest a relevant antimuscarinic drug action. Chronic administration of reboxetine at therapeutic doses causes autonomic dysfunction and subjective sedation but does not impair cognitive and psychomotor abilities in healthy humans.

Transcranial doppler sonography-ergometer test for the non-invasive assessment of cerebrovascular autoregulation in humans.

Cerebrovascular hemodynamics during physical stress have been sparsely investigated, mostly through risky invasive techniques. The aim of this study was to determine the effect of ergometer stress on cerebrovascular hemodynamics in humans using the non-invasive and thus clinically-applicable method of transcranial Doppler sonography (TCD) combined with simultaneous non-invasive measurements of cardiovascular parameters. In eighteen healthy subjects (six women, twelve men; 29.3+/-4.6 years old) left midcerebral artery blood flow velocities (CBFVs) were continuously monitored using TCD during 3 min at rest, 3 min during ergometry and 3 min recovery. Simultaneously, systolic, diastolic, mean CBFVs, pulsatility index (PI), heart rate, beat-to-beat blood pressure (BP) and transcutaneous p(CO(2)) were measured. The subjects were supine with elevated trunk. Ergometry was performed by pedalling a Mühe-ergometer. In eight volunteers, the procedure was repeated within the next day to test the repeatability of the results. Heart rate increased significantly during ergometry (from 65.2+/-11 to 105. 3+/-12.3/min; P<0.05). The systolic BP increased significantly slightly later during ergometry (from 118.9+/-8.6 to 141.6+17.9 mmHg; P<0.05). Transcutaneous p(CO(2)) was initially within physiological ranges, but increased significantly after a delay during the 3rd min of cycling (from 39.7+/-3.7 to 41.1+/-4.7 mmHg; P<0.05). MFV started to rise significantly after 1 min of the exercise period (from 59.6+10.9 to 68.3+13.9 cm/s; P<0.05). PI increased immediately and significantly at the start of exercise (PI at rest 0.93+0.11; PI ergometry 1.1+0.13; P<0.05). The results were found to be reproducible in the eight volunteers. The cerebrovascular changes during ergometer exercise may reflect the combined activation of the cerebrovascular autoregulative mechanisms (neurogenic, myogenic and metabolic). The TCD-ergometer test presented here is non-invasive and would seem to present a low risk for patients who are judged fit enough for mild exercise. The test may contribute to the detection of cerebrovascular abnormalities in various diseases.

Transcranial Doppler sonography during acute 80 degrees head-down tilt (HDT) for the assessment of cerebral autoregulation in humans.

Cerebrovascular hemodynamics during postural changes have been sparsely investigated despite the fact that abnormal responses may contribute to the risk of stroke. The aim of this study was to determine the effect of acute 80 degrees head-down tilt (HDT) on cerebrovascular hemodynamics in humans using transcranial Doppler sonography (TCD). In 13 healthy volunteers (2 female, 11 male, age 19-37 years, mean age 26.8 years) left midcerebral artery blood flow velocities (CBFVs) were continuously monitored using TCD during 180 sec in horizontal position and during 60 sec of 80 degrees HDT. Simultaneously, systolic, diastolic, mean CBFVs, pulsatility index (PI), heart rate, beat-to-beat blood pressure (BP) and transcutaneous pCO2 were measured. In five volunteers, the procedure was repeated the next day to test the repeatability of the results. Mean BP increased slightly, but not significantly during tilt (from 80.5 +/- 7.7 mmHg to 85.9 +/- 14.1 mmHg; p > 0.05). Heart rate decreased significantly during the first 20 sec of HDT (from 66.8 +/- 9.9 min-1 to 60 +/- 11 min-1; p < 0.05). Transcutaneous pCO2 was within physiological ranges during the whole procedure (mean pCO2 minimum 39.5 +/- 2.9 mmHg, mean pCO2 maximum 42.2 +/- 3.3 mmHg). Mean CBFV did not change significantly during tilt (from 70.1 +/- 19.1 cm sec-1 to 66.6 +/- 14.1 cm sec-1; p > 0.05). PI, however, increased significantly with a more pronounced increase during the first 20 sec than the last 40 sec of tilt (PIsupine 0.92 +/- 0.11; PItilt(0-20 sec) 1.15 +/- 0.18; PItilt(21-60 sec) 1.03 +/- 0.16; p = 0.001; p = 0.017). The HDT results were found to be reproducible in the five volunteers. During 80 degrees-HDT mean BP and pCO2 did not change significantly. This observation combined with the significant decrease in heart rate during the first 20 sec of HDT, suggests that there is no sympathetic activation. The significant PI increase during HDT indicates a vasoconstriction of the cerebral resistance vessels. We assume that this vasoconstriction is due to the myogenic mechanism of cerebrovascular autoregulation triggered by a rapid, passive intracranial blood volume influx during HDT.

Transcranial Doppler sonography during acute 80° head-down tilt (HOT) for the assessment of cerebral autoregulation in humans.

Cerebrovascular hemodynamics during postural changes have been sparsely Investigated despite the fact that abnormal responses may contribute to the risk of stroke. The aim of this study was to determine the effect of acute 80° head-down tilt (HDT) on cerebrovascular hemodynamics in humans using transcranial Doppler sonography (TCD). In 13 healthy volunteers (2 female, 7 1 male, age 19-37 years, mean age 26.8 years) left midcerebral artery blood flow velocities (CBFVs) were continuously monitored using TCD during 180 sec in horizontal position and during 60 sec of 80° HDT. Simultaneously, systolic, diastolic, mean CBFVs, pulsatility index (PI), heart rate, beat-to-beat blood pressure (BP) and transcutaneous pC02 were measured. In five volunteers, the procedure was repeated the next day to test the repeatability of the results. Mean BP increased slightly, but not significantly during tilt (from 80.5± 7.7 mmHg to 85.9 ±14.1 mmHg; p < 0.05). Heart rate decreased significantly during the first 20sec of HDT (from 66.8± 9.9 min-1 to 60± 11 min-1; p> 0.05). Transcutaneous pC02 was within physiological ranges during the whole procedure (mean pC02 minimum 39.5±2.9 mmHg, mean pC02 maximum 42.2±3.3 mmHg). Mean CBFV did not change significantly during tilt (from 70.1 ± 7 9.1 cm sec-1 to 66.6 ± 14.1 cm sec-1; p < 0.05). PI, however, increased significantly with a more pronounced increase during the first 20 sec than the last 40sec of tilt (Plsupine 0.92±0.11; Pltnt(0-20sec) 1.15±0.18; Pltnt(2i~6o sec) 1-03±0.16; p = 0.001; p = 0.017). The HDT results were found to be reproducible in the five volunteers. During 80°-HDT mean BP and pC02 did not change significantly. This observation combined with the significant decrease in heart rate during the first 20 sec of HDT, suggests that there is no sympathetic activation. The significant PI increase during HDT indicates a vasoconstriction of the cerebral resistance vessels. We assume that this vasoconstriction is due to the myogenic mechanism of cerebrovascular autoregulation triggered by a rapid, passive intracranial blood volume influx during HDT. [Neurol Res 1999; 21: 457-462].

Cardiovascular effects of sildenafil citrate (Viagra): a naturalistic cross-over study.

In a cross-over study we investigated the effects of sildenafil (single doses of 25- or 50mg) on cardiovascular autonomic nervous system (ANS) function assessed by serial recordings of blood pressure, conventional 12-lead electrocardiograms and standardized, time-and frequency domain indices of heart rate variability (HRV) in 21 men with erectile dysfunction. More than half of these patients had multiple comorbidities. Sildenafil induced significant mean reductions from baseline in resting blood pressure, accompanied by a reflex increase in heart rate. There were no significant changes after administration of sildenafil in any other of the ANS function indices. These preliminary findings suggest that sildenafil does not significantly affect cardiac ANS function in patients with erectile dysfunction.

[Light-evoked blood flow changes in the posterior cerebral artery]. / Licht-evozierte Blutflussänderungen in der Arteria cerebri posterior.

In 20 healthy volunteers light evoked changes in blood flow of the posterior cerebral artery were studied with color coded Doppler sonography. Doppler flow profiles of the PCA were recorded before, during and after exposition with light. Under the treatment with light the RI decreased in the mean form 0.61 down to 0.50, indicating an increase of flow. After redarking the RI increased again up to a mean of 0.62. The applied test could be a helpful tool to clarify the pathophysiological mechanism in defect seeing.

[Noise-induced changed in basilar circulation]. / Geräusch-evozierte Anderungen der Basilarisdurchblutung.

In 55 volunteers with good hearing, sound-evoked changes in the blood flow of the basilar artery were studied using colour coded Doppler sonography. After a rest of twenty minutes 2 groups of subjects listened to sound of varying volume using a head phone. In one group (n = 25) the sound volume was 25 dB and in the second group (n = 30) the volume was 65 dB. In both groups significant sound evoked changes of vascular resistance were found, quantified by the RI. In the case of applying soft sound (25 dB) the RI decreased, indicating an increase of volume flow while with louder sound (65 dB) the RI increased, indicating a reduction of flow.

[Respiration-dependence of cutaneous laser Doppler flow motion]. / Atemabhängigkeit kutaner Laser-Doppler-Fluxmotion.

The aim of this study was to show and to quantify the breath-dependency of cutaneous fluxmotion in the volar proximal forearm using a new computer-aided system. A meanflux-related index (MI) representing the intensity of the influence of respiration on fluxmotion was calculated. There was a good correlation between MI and the rate of respiration under spontaneous breathing: the lower the rate of respiration, the higher the value of MI. Prescribing a constant breathing rhythm amplifies this frequency-dependent effect. According to occurrence of low rates of respiration (< 12/min) also under physiological conditions the respiration should be simultaneously recorded while assessing fluxmotion.

Rhythmical changes of the cutaneous blood flow in the forehead region under the condition of hypnoid relaxation.

BACKGROUND: A characteristic and stable blood flow rhythm can be detected for the skin of the forehead and ear lobes with frequencies of approx. 0.15 Hz (9/min), which were primarily not related to the respiratory rhythm. PATIENTS AND METHODS: The perfusion of the skin in the forehead region was investigated non-invasively with laser Doppler fluxmetry in ten healthy subjects before and during Hypnoid Relaxation (HyR). The HyR-state was induced by suggesting formulas regarding to the well known Autgeneous Training. RESULTS: In all test subjects rhythmical fluctuations of bloodflow with a frequency of approx. 0.15 Hz could be observed both, before and during HyR. We found that the amplitude of these fluctuations clearly (> 20% from individual baseline) increased in five of ten test subjects under the condition of HyR. Furthermore, in three of ten cases the spontaneous respiration under HyR adjusted to the frequency of the described bloodflow rhythm, which exists both, before and during HyR. CONCLUSIONS: These phenomena suggest an individually stabil and autonomous rhythm which is effected by alterations in the level of conciousness and which may be caused by the close linkage between the nerval structures for control of respiratory and circulatory systems. May be, this autonomic rhythm could be used as a trigger for breathing therapies or as a parameter for the impact of relaxation techniques on hemodynamics, e.g. in complementary therapy of vascular diseases like systemic sclerosis.

[Inspiration-triggered vasoconstrictive episodes in healthy subjects, in patients with diabetes mellitus and in patients with clinically manifest polyneuropathy of variable origin. A simple Doppler ultrasound test to assess the autonomic vascular functional unit of the upper extremity]. / Inspirationsgetriggerte vasokonstriktorische Episoden bei Gesunden, bei Patienten mit Diabetes mellitus sowie bei Patienten mit klinisch manifester Polyneuropathie unterschiedlicher Genese. Ein einfacher Ultraschall-Doppler-Test zur Prüfung der autonomvaskulären Funktionseinheit an der oberen Extremität.

BACKGROUND: A cost- and time efficient ultrasound-Doppler-test is introduced to evaluate the function of autonomic innervation of the upper limb. A voluntary inspiratory vasoconstrictor episode (VICE) after a provoked deep inspiration, transmitted via sympathetic nervous system, can be demonstrated at the radial artery using basic Doppler equipment. PATIENTS AND METHOD: VICEs were investigated in 30 healthy subjects (group A), in 20 patients with diabetes mellitus without clinical signs of polyneuropathy (group B) and in 20 patients with clinically manifest polyneuropathy (group C). RESULTS: In all healthy subjects a two minutes arterial occlusion led to a decrease of resistance index (RI) lower than 0.9 indicating sufficient hyperemia. RI during VICE increased to 1.0 in all healthy subjects. In 50% of the patients of group B as well as in 50% of the patients of group C the test revealed abnormal findings suggesting a disorder of the functional peripheral neurovascular unity.

[Urine test strips for cerebrospinal fluid diagnosis of bacterial meningitis]. / Urinteststreifen zur Liquordiagnostik der bakteriellen Meningitis.

BACKGROUND: Diagnosis of bacterial meningitis is due to granulocytic pleocytosis of CSF. In developing countries and in hospitals without continuous availability of a clinical laboratory a bedside-method of diagnosing meningitis is desired. METHODS: 75 CSF samples were tested for granulocytes and protein with reagent strips and the results were compared with those obtained from the clinical laboratory. RESULTS: All 48 samples with normal cell count were correctly diagnosed negative using reagent strips. Twenty-five samples of 27 samples with granulocytic pleocytosis were correctly recognised as right positive (sensitivity 92.6%; specificity 100%). All 48 samples with normal protein were correctly tested normal. Twenty-one samples of 27 samples with elevated protein were correctly diagnosed right positive (sensitivity 77.8%; specificity 100%). CONCLUSION: Testing CSF for granulocytes and protein with urine reagent strips is a bedside-method which allows a rapid and reliable decision whether CSF is normal or granulocytically pleocytotic.

Sildenafil affects olfactory function.

PURPOSE: Sildenafil is the first member of a new class of oral drugs effective for erectile dysfunction. However, approximately 20% of patients complain about nasal congestion after sildenafil administration. MATERIALS AND METHODS: Because nasal airflow and olfaction are closely linked, the sense of smell was evaluated in 20 young, healthy volunteers after the administration of 50 and 100 mg sildenafil, and placebo in a double-blinded, crossover study. Olfactory function was evaluated using a standardized and validated test (Sniffin' Sticks). To investigate a possible impact of G-protein beta3 subunit C825T polymorphism on the effect of sildenafil on olfaction the genotype of all subjects was determined. RESULTS: The effect of sildenafil on olfaction was only present at a dose of 100 mg but not at a dose of 50 mg sildenafil. The genotypes TT, CC and TC of the G-protein beta3 C825T polymorphism had no impact on the change in olfactory function. CONCLUSIONS: Higher sildenafil doses may produce decreased olfactory sensitivity.

[Measuring basilar artery blood flow velocity with transcranial Doppler and and transcranial Doppler color ultrasound]. / Messung der Basilaris-Flussgeschwindigkeit mittels TCD und TCCD.

GOAL: The aim of the present study was to clarify, by means of transcranial colour-coded duplex sonography of the basilar artery, whether there are changes in basilar artery blood flow in patients with acute inner ear disturbances and whether the flow in the basilar artery is affected by acoustic stimuli in such patients and in normal, healthy controls. METHOD: Basilar artery blood flow velocity was measured in 52 patients with severe inner ear impairment over a period of two weeks by means of conventional transcranial Doppler sonography and transcranial colour-coded duplex sonography. The same measurements were carried out in 45 healthy control subjects. At the end of the two week period, both patients and controls were exposed to 70-dB noise, with basilar artery flow evaluated before and during exposure. The basilar artery Doppler curves were analysed for systolic flow velocity, end-diastolic flow velocity, resistance index (Pourcelot) and pulsatility index (Gosling). RESULTS: During the first two days of the study, the basilar artery resistance index and pulsatility index were significantly (p < 0.001) higher in patients than in controls. During noise exposure, both patients and controls showed significant (p < 0.01) increases in these indices. CONCLUSION: This study shows that temporary increases in the basilar artery resistance index and pulsatility index are found both in the acute phase of inner ear disease and during exposure to noise.

[High frequency color coded duplex ultrasound of small finger arteries--new diagnostic possibilities? A noninvasive method for visualizing digital circulation]. / Die hochfrequente farbkodierte Duplex-Sonographie kleiner Fingerarterien--neue diagnostische Möglichkeiten? Eine nichtinvasive Methode zur Visualisierung der digitalen Strombahn.

Small vessels with luminal diameters of 0.2-2.0 mm have not been studied with routine ultrasound diagnostic procedures. Modern color Doppler imaging technology, however, should allow visualization of the blood flow even in such small vessels. The present study was therefore aimed at demonstrating the possibilities of examining small arteries in the fingertips of healthy volunteers with color Doppler imaging. The question was whether or not a standardized visualization was possible. We found that small arteries and their blood flow could be demonstrated in all (n = 10) healthy subjects. Furthermore, we demonstrated pathologic findings in the fingertip arteries of a patient with thrombangitis obliterans as an example of the diagnostic value of these new procedures.

The effects of St John's wort extract on heart rate variability, cognitive function and quantitative EEG: a comparison with amitriptyline and placebo in healthy men.

AIMS: To compare the effects of multiple dosing with St John's wort (Hypericum perforatum) extract and amitriptyline on heart rate variability, cognitive function and quantitative EEG (qEEG) with placebo in healthy humans. METHODS: A randomized, double-blind, cross over study of 12 healthy male volunteers. Subjects orally received capsules with 255-285 mg St John's wort extract (900 micro g hypericin content), 25 mg amitriptyline and placebo three times daily for periods of 14 days each with at least 14 days between. The doses of amitriptyline and St John's wort extract are comparable with respect to their antidepressant activity. Compliance was confirmed by coadministration of 10 mg of riboflavin with each capsule and detection of urinary vitamin B2 on treatment day 11 with high performance liquid chromatography. Measurements of heart rate variability, psychometric tests and qEEG were performed before start of medication and repeatedly on the last treatment day. RESULTS: St John's wort extract did not affect heart rate variability (HRV) whereas amitripytline significantly decreased it: the difference in the percentage number of adjacent RR intervals> 50 ms (pNN50) was 8.6 (-2.6, 19.9; mean; 95% confidence interval) between St John's wort extract and placebo and -17.6 (-24.7, -10.4) between amitriptyline and placebo. Neither St John's wort extract nor amitriptyline had an influence on cognitive performance such as choice reaction, psychomotor coordination, short-term memory and responsiveness to distractive stimuli. Amitriptyline but not St John's wort extract decreased self rated activity (P < 0.05). Both drugs caused significant qEEG changes. St John's wort extract increased theta power density. Amitriptyline increased theta as well as fast alpha power density. CONCLUSIONS: Multiple doses of St John's wort extract do not affect heart rate variability nor cognitive function. Chronic administration of amitriptyline causes a decrement of HRV and subjective sedation but it does not impair cognitive performance.

Vestibular evoked blood flow response in the basilar artery.

BACKGROUND AND PURPOSE: Monitoring of the basilar artery (BA) is difficult and has been sparsely performed. The aim of this study was to present physiological data of functional transcranial Doppler sonography (TCD) of the BA during caloric vestibular stimulation in healthy volunteers. METHODS: TCD of the BA was performed in 26 healthy volunteers (14 women, 12 men, age 25.1+/-3 years) during caloric vestibular stimulation. Vertigo was documented using electronystagmography (ENG) and a subjective vertigo scale ranging from 0 to 10 points. Simultaneously, capnogpraphy was performed. RESULTS: All subjects experienced vertigo, nausea and oszillopsia during vestibular irrigation. The average subjective vertigo was for a period of 106 s (+/-65.4); the average subjective estimated degree of vertigo was 6.7 points (+/-1.5). In all subjects, ENG demonstrated horizontal nystagm to the left non-irrigated side. In 14 subjects the subjective vertigo was rated by the individuals as extreme (point score > or =7) and in 12 subjects as low (point score <7). Mean flow velocity (MFV) in the BA increased significantly during vestibular irrigation, being more prominent in the initial irrigation and vertigo phase (5.8+/-5.9%, P<0.05) than in the second vertigo phase (2.2+/-8.8%, P<0.05). The calculated pulsatility index (PI), which indicates the condition of the small resistance vessels, decreased significantly (-4.9+/-8.1%; 4.3+/-8.9%, P<0.05) during both phases of vestibular activation. End tidal pCO2 did not change significantly (constant 5.4+/-0.4 Vol%), but respiration frequency was significantly increased during vestibular stimulation (12.3+/-3.8 min(-1) to 16.4+/-5.3 min(-1) and 16.3+/-4.8 min(-1), P<0.05) probably as a vegetative sign of vertigo. The observed MFV- and PI-changes were more prominent, although not quite significant, in the subgroup of subjects who experienced extreme subjective vertigo than in the subgroup who experienced low subjective vertigo. CONCLUSION: These observations indicate that MFV increase in the posterior circulation is due to activation of the vestibulocerebellum. In addition, it is possible that the previously elaborated MFV increase in the MCA might contribute to MFV increase in the BA via the posterior communicating artery. The difference in the 2 subgroups (extreme vertigo vs. low vertigo) may reflect the great variety of anatomical and physiological conditions of the peripheral vestibular organ, the brainstem anatomy and the corresponding blood supply. For clinical purposes this TCD-test may contribute to the investigation of the vasomotor reserve of the posterior circulation, e.g. in patients with vertebrobasilar ischemia, bilateral vestibular loss or local neurodegenerative disease.

Respiratory-dependent laser-Doppler flux motion in different skin areas and its meaning to autonomic nervous control of the vessels of the skin.

The aim of this study is to evaluate and quantify the respiratory dependency of cutaneous laser-Doppler flux motion in two variable innervated sites of the upper extremity (the proximal volar forearm and the fingertip) by using a computer-supported system. Various spontaneous (6-17/ min) and externally triggered (12 or 6/min) respiratory frequencies were used for comparative frequency analysis of the laser-Doppler flux signal. Further, an index (MIRSF) was determined as an indicator of the correlation between flux motion and respiration. The MIRSF is defined as the ratio of the power spectrum of the LDF signal at the specific respiratory frequency divided by the time-averaged LDF for that time period. The MIRSF enables a comparison of different intra- and interindividual flux values. A very high correlation was seen between the respiratory frequency and the MIRSF during spontaneous respiration in the skin of the proximal volar forearm; the lower the spontaneous respiratory frequency, the higher the MIRSF. However, this correlation could not be found in the results of the fingertip. The presence of a constant and therefore externally triggered respiratory frequency increased the modulations of the LDF at both measurement locations. While triggered respiration produced a decline in the taLDF of the fingertip, the taLDF of the forearm was unaffected. Considering the different innervation and hydrostatic effects the results lead to the following conclusion: the finger vessels are richly innervated with adrenoceptors which causes alpha 1-mediated vasoconstriction. In contrast to the vessels of the fingers those of the forearm seem to be under andrenergic as well as cholinergic control. Hydrostatic components appear to be more prevalent in the volar forearm site.

[Color-coded duplex ultrasound and laser Doppler flowmetry of finger tips of healthy probands]. / Farbkodierte Duplex-Sonographie und Laser-Doppler-Fluxmetrie in Fingerkuppen Gesunder.

In the study presented, color-coded duplex sonography (CCDS) and laser Doppler flux (LDF) signals from finger tips of 7 healthy individuals were recorded simultaneously. The aim of the study was to examine whether or not the results of a functional test ('deep inspiration') could also be observed with an ultrasonic Doppler. In the literature this test is known to provoke notable blood flow characteristics of the LDF ('inspiratory gasp'), a phenomenon which is caused by a sympathetically mediated vasoconstriction of acral vessels. With regard to the penetration depth of the LDF in skin it was of further interest to determine the distance between the surface of the skin and the vessels found near the surface. We found for CCDS parameters (color pixels/image; time-averaged flow velocity [TAV]; resistance index [RI]) as well as for LDF (flux [taLDF]) significant changes before versus after 'deep inspiration'. CCDS is a new diagnostic tool to visualize also very small vessels down to 0.2 mm, e.g. in finger tips. It should be evaluated which role this method may play in combination with functional tests in diagnostic handling, e.g. of patients with polyneuropathies or collagenoses.

[Dynamic function tests for detection of physiologic and pathophysiologic reactions in cutaneous microcirculation]. / Dynamische Funktionstests zur Erfassung physiologischer und pathophysiologischer Reaktionsmuster kutaner Mikrozirkulation.

Functional tests simulating local stresses are especially suitable for the evaluation of physiological and pathophysiological patterns in the cutaneous microcirculation, particularly if combined with non-invasive methods such as laser-Doppler fluxmetry and oxygen tension measurements. Arterial occlusion (3 min) and local heating (up to 42 degrees C) are appropriate as stimuli to simulate specific local demands on the cutaneous perfusion similar to those produced by pressure, myokinesis, heat, and inflammation. When the current microcirculatory status is described the initial values (LDF and pO2) and their time-courses during each functional test can be used to determine the so-called post-stimulatory parameters. These-- corresponding to physiological equivalents--allow statements on the vascular reactivity towards hypoxia and ischaemia. Furthermore, dynamic performance parameters can easily be derived from the poststimulatory values. They describe the capacity of cutaneous microcirculation with regard to perfusion reserves and ischaemic tolerance in local stress situations in an appropriate manner. As an example of the usefulness of functional tests for cutaneous microcirculation, the physiological and pathophysiological patterns found in systemic sclerosis are described.