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Biomedical subjects

P Pauschinger

Publications and source records attributed to P Pauschinger.

At least 19 recordsLinked to original sources
PubMed1993

Effects of corticotropin-releasing factor on isolated rat heart activity.

We investigated effects of bolus administration of corticotropin-releasing factor (CRF) on parameters of cardiac activity in isolated working rat hearts. Effects at a dose of 5 micrograms of CRF were compared in hearts perfused with Krebs-Henseleit solution, norepinephrine (NE, 10(-9) M), propranolol (3 x 10(-6) M), NG-nitro-L-arginine (L-NNA, 3 x 10(-5) M), or indomethacin (3 x 10(-5) M). CRF increased coronary flow for > 30 min (P < 0.01) with maximum increases of 31.7%, suggesting a prolonged vasodilatory action of the peptide. CRF, in addition, induced transient (lasting < 10 min) increases in maximum aortic pressure and oxygen consumption (P < 0.01), suggesting an inotropic action of the peptide. Perfusions of NE and propranolol did not change the cardiac response to CRF. L-NNA, inhibiting release of endothelium-derived relaxant factor (EDRF), and indomethacin diminished the vasodilatory response to CRF, as indicated by significantly shortened increases in coronary flow after CRF (P < 0.05). Indomethacin also enhanced peak increases in maximum aortic pressure after CRF (P < 0.01). The data confirm direct effects of CRF on cardiac activity. They also suggest that the mediation of coronary vasodilation by CRF involves the endothelial release of prostacyclin and EDRF.

Animals↗
PubMed1992

Norepinephrine amplifies effects of vasopressin on the isolated rat heart.

We compared effects of perfusion of norepinephrine (NE, 10(-9) mol l-1 and of unchanged Krebs-Henseleit solution on the cardiac response to bolus injection of arginine vasopressin (AVP, 2 ng). 14 isolated rat working heart preparations were used in a balanced cross-over design. Coronary flow, oxygen consumption and extraction, heart rate and total flow were continuously recorded. The concentration of NE was below that exerting per se systematic influences on cardiac activity. However, NE changed the cardiac response to AVP: (1) the AVP-induced reduction in coronary flow was greater during NE (mean: 41.7%) than vehicle perfusion (30.5%, P less than 0.005. (2) The AVP-induced decrease in oxygen consumption was stronger on top of the NE (41.5%) than vehicle perfusion (33.6%, P less than 0.005). (3) Following AVP, oxygen extraction during NE was increased compared to oxygen extraction during vehicle perfusion (3.61 +/- 0.03 vs. 3.46 +/- 0.02 microliters O2 ml-1 g-1, P less than 0.005). Results support the view of a potentiating role of catecholamines for direct cardiovascular effects of AVP.

Animals↗
PubMed1992

Dilatory and inotropic effects of corticotropin-releasing factor (CRF) on the isolated heart. Effects on atrial natriuretic peptide (ANP) release.

The effects of CRF administration on cardiac performance, coronary flow and ANP release were investigated in the rat heart. Isolated hearts were perfused at a constant filling pressure according to working heart model with a Krebs-Henseleit solution containing glucose and insulin, saturated with a gas mixture containing 95% O2 and 5% CO2. Administration of CRF via a cannula into the left atrium elicited a prolonged increase in the coronary flow rate and a transient increase in the aortic pressure resulting in an overall increase in the pressure-volume work. The oxygen consumption, after the administration of CRF, increased in accordance with the cardiac effort. No changes were observed in the spontaneous heart rate. Furthermore, administration of CRF induced a short-term increase of ANP release into the coronary perfusate. Our experiments suggest that administration of CRF produces a prolonged dilatory effect on the coronary arteries while producing a transient positive inotropic effect and a transient increase of ANP release on the isolated rat heart.

Animals↗
PubMed1991

Adrenergic influences on cardiac function during ventricular fibrillation in isolated rat hearts.

Effects of norepinephrine (NE, 10(-6) M), epinephrine (E, 10(-6) M), and vehicle on coronary blood flow (CF), oxygen consumption, and lactate release were compared in 32 isolated rat hearts during 5 min of ventricular fibrillation (VF). After VF, tissue concentrations of ATP, AMP, creatinine phosphate (CP), and lactate were measured. Perfusion of treatments started 30 s after onset of VF and was maintained throughout VF. CF during VF was greater (P less than 0.005) during perfusion of E (mean +/- SE, 5.73 +/- 0.15 ml/min) than NE (5.06 +/- 0.32 ml/min) or vehicle (5.11 +/- 0.18 ml/min). Oxygen consumption during VF was higher during perfusion of E (29.5 +/- 0.9 microliters.min(-1).g wet heart wt(-1)) than vehicle (27.3 +/- 0.7 microliters.min(-1).g(-1); P less than 0.05); average oxygen consumption during NE (27.6 +/- 1.4 microliters.min(-1).g(-1)) and vehicle were comparable. After NE, but not E, tissue AMP concentrations were significantly increased, and CP concentrations were reduced compared with vehicle (P less than 0.05). Enhanced consumption of high-energy phosphates during NE suggests that there is also an enhanced demand for oxygen. However, unlike during E, during NE this demand is not met by an augmented CF. Thus, compared with E, NE treatment during VF may increase the risk of hypoxic damage.

Adenosine Monophosphate↗
PubMed1990

Influences of peripheral adrenocorticotropin 1-39 (ACTH) and human corticotropin releasing hormone (h-CRH) on human auditory evoked potentials (AEP).

Hormones of the hypothalamus-pituitary-adrenal (HPA) axis have been considered to form part of an efferent humoral system modulating central nervous stimulus processing. The present experiments were designed to compare the effects of iv bolus administrations of placebo, porcine ACTH 1-39 (1.5 U) and h-CRH (25 micrograms) on auditory evoked potentials (AEPs) in healthy men. Also, cardiovascular parameters, cortisol and self-reported mood were assessed. ACTH significantly reduced the amplitude of the N1 component of the AEP; P1 and P2 remained unchanged. The selective reduction of N1 amplitude defies an interpretation of the changes in terms of a reduced stimulus-induced cortical arousal following ACTH; the ACTH-induced changes may rather indicate an influence on frontocortical functions of directing attention. The effect of ACTH on N1 cannot be attributed to its adrenocorticotropic action or to cardiovascular changes, but appears to represent an intrinsic extraadrenal influence of the hormone. The data do not provide evidence for effects of h-CRH on central nervous stimulus processing in humans, after peripheral administration.

Adrenocorticotropic Hormone↗
PubMed1990

[Late vascular damage after unilateral leg amputation].

The higher incidence of infrarenal aortic aneurysms in war-veterans with above knee amputations indicates that leg amputation besides arteriosclerotic risk factors constitutes a relevant pathogenetic factor for the late development of an abdominal aortic aneurysm. A retrospective study of 25 mainly young patients with above knee amputation showed that already one year after leg-loss a typical adaptive narrowing of the pelvic and leg arteries with significant reduction of the flow volume of 37% on the amputated side could be registered. Unilateral flow reduction resp. interruption causes an asymmetric flow pattern at the aortic bifurcation. The changed hemodynamics are probably the main cause for late damage to the aorto-iliac vessels. The clinical importance of these results is that patients with unilateral leg amputation should have regular follow up investigation in order to detect late sequelae on the aorto-iliac vessels and to perform elective surgery for abdominal aortic aneurysm. Ipsilateral occlusive arterial disease as well as abdominal aortic aneurysms must be regarded as secondary late damage after leg amputation justifying obligatory indemnification.

Adolescent↗
PubMed1989

Aortic aneurysms as late sequelae of above-knee amputation.

The infrarenal aorta was examined by ultrasound in 329 men who had lost a leg in World War II and in 702 war veterans. The groups were similar in terms of age and risk factors for arteriosclerosis. Abdominal aortic aneurysms were found in 5.8% of the amputees compared with 1.1% of the non-amputees. Unilateral flow reduction after leg amputation causes an asymmetrical flow pattern at the aortic bifurcation, and this is probably the main cause of late damage to the aorta.

Aged↗
PubMed1989

Effects of cholecystokinin and calcitonin on evoked brain potentials and satiety in man.

Central nervous effects of the peptides cholecystokinin (CCK) and calcitonin (CT) were tested in an attention task for their effects on Auditory Event Related Potentials (AERPs) and for their effects on satiety and activation as measured in self-rating scales. Thirteen healthy subjects received either 3 IDU/kg bodyweight CCK 1-33, 0.1 IU/kg bodyweight CT and placebo according to a double-blind within-subject cross-over design. Subjects had fasted for at least 16 hr prior to the experiment. CCK induced the feeling of satiety after stimulation with the preparation of a meal. The peptides prevented an attenuation of the N2-component of the AERP after the preparation of a meal, indicating that the subjects were less distracted by the food cues. The results suggest that the central nervous effects of CCK and CT may constitute an aspect of satiated behavior.

Adult↗
PubMed1989

Influences of cortisol on auditory evoked potentials (AEPs) and mood in humans.

The present study was designed to investigate effects of cortisol on evoked potential indicators of sensory processing and on mood in 45 healthy human subjects. In order to determine the glucocorticoid effect to be primary excitatory or inhibitory, the vertex potential components. (P1, N1, P2) of the auditory evoked potential (AEP) were assessed, which also indicate a stimulus-induced cortical arousal response mediated by the nonspecific sensory system of the reticular formation. The AEPs were recorded while the subject performed a vigilance task containing 8 blocks of monotonous series of tone pips presented at different interstimulus intervals. Mood was assessed by an extensive adjective checklist. Experiments were held double-blind and designed as between-group comparison. Subjects received either 40 or 20 mg hydrocortisone (constantly infused between 35 min prior to testing till the end of the experiment), or placebo. Enhanced plasma cortisol levels were related to increased amplitudes of the AEP vertex response. Furthermore, cortisol augmented self-reported concentration and reduced tiredness during task performance. The glucocorticoid effects on both AEPs and self-report measures suggest an excitatory influence of cortisol on brainstem and thalamic mechanisms mediating the stimulus-induced cortical arousal.

Adolescent↗
PubMed1988

[Aneurysm of the abdominal aorta and leg amputation. A chance coincidence or a pathogenetic correlation?].

A retrospective analysis of 545 patients, operated on between 1970 and 1987 for a closed or ruptured infrarenal aneurysm of the abdominal aorta (AAA), revealed an incidence of 5.1% of unilateral leg amputations among them (20 above, 8 below the knee) during the Second World War. Patients in both groups (with or without amputation) had one or more arteriosclerotic risk factors, their frequency rising with increasing age. There were differences between the two groups in the frequency of certain morphological characteristics in the area of the bifurcation and the terminal aorta affecting the haemodynamics of these regions. Stenosis or occlusion of the ipsilateral iliac arteries may be a possible pathogenetic factor. A prospective study will be required to decide whether the coincidence between leg amputation and AAA is pathogenetic or accidental.

Age Factors↗
PubMed1987

Dose-dependent influences on electrophysiological signs of attention in humans after neuropeptide ACTH 4-10.

The afferent humoral system exerts significant influences on brain activity. Central nervous actions of the adrenocorticotropic hormone (ACTH) are most likely to be mediated by information coded in a portion of this hormone structure corresponding to ACTH 4-10. Our previous research suggested an impairing effect of ACTH 4-10 on electrophysiological signs of selective attention in humans. The present experiments in 12 male subjects investigated the influences of ACTH 4-10 on different aspects of attention as indicated by auditory event-related potential (AERP) components. Furthermore, dose-response characteristics of these influences should be examined. Attention performance was tested in a dichotic listening paradigm, after 0, 0.1, 1.0, and 10 mg ACTH 4-10, administered intravenously 1 h prior to testing according to a double-blind latin-square design. Different aspects of attention were measured by brain electrical responses evoked either by frequent standard or rare target tone pips, which the subject had to attend to, or to ignore. The selective type of attention was reflected by the Nd determined as mean difference in amplitude between AERPs to tone pips when attended and when unattended, for a latency range between 0-460 ms post-stimulus. In addition, plasma cortisol, heart rate, blood pressure, and behavioral performance were measured. Results indicated a clear reduction of the Nd amplitude after all doses of ACTH 4-10. Other indicators of attention mechanisms such as mismatch processing were not affected by the peptide. The diminished Nd after ACTH 4-10 was due to an increased processing of unattended stimuli, but simultaneously attended tones were processed less intensively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

[Effects of horse-chestnut seed extract on transcapillary filtration in chronic venous insufficiency].

The effect of horse-chestnut seed extract (standardized on aescin; Venostasin retard) was assessed in a randomized placebo-controlled crossover double-blind trial of 22 patients with proven chronic venous insufficiency by measuring the capillary filtration coefficient and the intravascular volume of the lower leg by venous-occlusion plethysmography. Three hours after taking two capsules of Venostasin (600 mg; each capsule containing 50 mg aescin) the capillary filtration coefficient had decreased by 22%, whereas after administration of an identical-looking placebo capsule it rose but slightly over three hours. The difference in the effect of Venostasin and placebo is statistically significant (P = 0.006). The intravascular volume was reduced 5% more after Venostasin than the placebo, but this is not statistically significant. It is concluded that Venostasin has an inhibitory effect on oedema formation via a decrease in transcapillary filtration and thus improves oedema-related symptoms in venous diseases of the legs.

Capillary Permeability↗
PubMed1986

Influences of corticosteroids, dexamethasone and hydrocortisone on sleep in humans.

The present two experiments were designed to investigate the effects of a synthetic and of a natural corticosteroid on nocturnal sleep in humans. Both experiments were held double-blind and designed according to a within-subject cross-over comparison. In the first experiment, 1 mg of dexamethasone applied orally prior to sleep (11.00 p.m.) led to a reduction of the percent of time spent in REM and in stage 4 sleep. The amount of stage 2 sleep tended to be increased after dexamethasone. In the second experiment, an infusion of 100 mg hydrocortisone throughout the night also reduced REM, but increased stage 4 sleep. A statistical comparison of both experiments suggested that both steroids not only reduced REM sleep but also tended to enhance intermittent wakefulness. This analysis also confirmed opposite effects on measures of slow-wave sleep of both substances. The results represent a first demonstration of differential effects of synthetic and natural corticosteroids on sleep, which has to be substantiated in further studies directly comparing effects of these steroids.

Adult↗
PubMed1985

A new sensitive method for the quantification of internal carotid stenoses by means of ultrasound Doppler signal processing.

A new way of processing the ultrasound Doppler spectrum is presented. By introducing a Disturbance Index (DI), based on a double Fourier transformation, the quantitative evaluation of blood flow disturbance is possible. The integral value of this index over the whole cardiac cycle can be used to quantify the degree of lower grade internal carotid artery (ICA) stenoses and plaques. In a preliminary study, this new method has been tested in 18 normal and 10 atherosclerotic carotid arteries against Duplex-scan and angiography. The results were compared with 5 alternative methods of processing the Doppler spectrum.

Carotid Arteries↗
PubMed1979

Synchronous determination of retinal circulation times in both eyes.

Retinal circulation times of 44 healthy subjects (88 eyes) were measured simultaneously on both eyes by means of synchronous bilateral fluorescein angiography. "Circulation time" was defined as the time from the first arterial filling to the first fluorescence of the corresponding vein close to the disc margin. We found 1.2 sec for the superior temporal vessels, 1.3 sec for the inferior temporal, 1.3 sec for the superior nasal, and 1.4 sec for the inferior nasal vessels of the right eye. For the left eye these values were 1.2 sec, 1.2 sec, 1.4 sec, and 1.4 sec, respectively. No significant differences between the 2 eyes were demonstrable. It is concluded therefore that in cases of monocular disturbances of retinal circulation the other eye can serve as a reliable standard when measurements are performed simultaneously on both sides. The many uncertainties of successive examinations caused by uncontrollable systemic circulation changes are thus eliminated.

Adult↗