Biomedical subjects

R Pluto

Publications and source records attributed to R Pluto.

5 recordsLinked to original sources

PubMed1988

Normal values of catecholamines in blood plasma determined by high-performance liquid chromatography with amperometric detection.

Norepinephrine (NE), epinephrine (EPI), and dopamine (DA) were determined in the blood plasma of 122 subjects by high-performance liquid chromatography with amperometric detection (HPLCA). The range of normal values in the supine position was 0.15-3.50 nmol/l for NE, 0.01-0.80 nmol/l for EPI, and 0.04-4.50 nmol/l for DA. The effect induced by inserting intravenous catheters, food intake, cigarette smoking, varying body positions, and sex differences are also presented in this paper. As a modified HPLCA method was used, we were able to examine a large collective group. Thus, it was possible to compare the results of other authors which have been found in smaller collective groups.

Adult↗

PubMed1988

Cardiocirculatory, hormonal, and metabolic reactions to various forms of ergometric tests.

The sympathoadrenergic reaction is not only dependent on the duration and intensity of work but also on the body position and the involvement of small or large muscle masses. This observation made in field tests comparing different sports disciplines such as swimming, running, or diving encouraged us to investigate this topic under the following laboratory conditions. Twelve healthy sport students participated in ergometric tests on a bicycle ergometer in a horizontal and vertical body position as well as on a treadmill and a swim bench ergometer. The changes of plasma catecholamines (CA) obtained in the different ergometric tests were compared with those cardiocirculatory, metabolic, and hormonal parameters which can be influenced by the sympathoadrenergic stimulation. In the horizontal body position we found a smaller increase of norepinephrine at submaximal and maximal work loads combined with a similar reaction of renin, whereas the diastolic blood pressure and the mean arterial blood pressure increased more. The substrates of lipolysis and aerobic and anaerobic glycolysis did not show obvious differences depending on the body position. In the swim bench test, however, the lactate increase started earlier and was comparatively higher than in the other ergometric tests in which the maximal work load and VO2max were higher. Although a smaller muscle mass was used and a lower maximal oxygen uptake was reached, we did not find statistically different CA values during the swim bench ergometric test compared with the bicycle ergometric test in a horizontal body position. In our ergometric tests, the venous CA levels (especially norepinephrine) were predominantly influenced by the body position.

Adult↗

PubMed1986

[Physiologic variability of plasma catecholamines].

In an earlier publication, we described a modified procedure for the determination of plasma catecholamine levels using high-performance liquid chromatography (HPLC), followed by amperometry. In this paper, we present our results on the variability of normal catecholamine values in plasma for noradrenaline (NA), adrenaline (A) and dopamine (DA). In 122 women and men at rest, the range for NA was 0.15-3.5 nmol/l, for A 0.01-0.8 nmol/l and for DA 0.04-4.5 nmol/l. We also describe the effects of orthostasis, intravenous catheters, food intake, cigarette smoking, age and sex on venous catecholamine levels. The efficiency of the HPLC method allowed us to check, using a large subject group, the results obtained by other authors from studies involving smaller subject groups with more expensive and time-consuming methods.

Adult↗

PubMed1984

Electrochemical detection of catecholamines in urine and plasma after separation with HPLC.

The catecholamines in plasma and urine were determined by electrochemical detection after separation on a HPLC column RCM 100 C 18. Linear calibration plots of epinephrine, norepinephrine and dopamine have been obtained in the range expected to appear in urine or plasma. Coefficients of variation (0.5 to 10%), recovery rates (60 to 80%) and the standard deviation were satisfactory, whereas plasma dopamine showed a greater variation (10-15%). The values ascertained by this technique were compared with those determined by the radioenzymatic assay of Da Prada et al. They showed a good correlation for norepinephrine r = 0.92, p less than 0.001 and epinephrine r = 0.80, p less than 0.01, but less for dopamine r = 0.1. Experimental details of isolation from plasma with Al2O3 adsorption and desorption with HClO4, and from urine with ion exchange chromatography on Bio-Rex 70 and elution with boric acid are described. Technical modifications which improve the method are reported. The optimized assay could reliably be employed in investigations of more than 3000 urine and plasma samples obtained from patients and athletes before and after exercise.

Chromatography, High Pressure Liquid↗

PubMed1980

Further evidence for a correlation between EEG synchronization and plasma DBH activity in normal subjects.

In a former investigation we had got evidence for a relationship between synchronization of the resting EEG and plasma dopamine-beta-hydroxylase (DBH) activity in healthy males. In order to substantiate this finding we now examined a new sample of males and a sample of females, both with either low-voltage or monotonous alpha-EEGs, and relatives of probands with either EEG type. In the new sample of males, the carriers of a low-voltage EEG (n = 15) again had significantly lower plasma DBH activity than the subjects with a monotonous alpha-EEG (n = 16). In females there was no difference. In the families of probands with a monotonous alpha-EEG the relatives carrying the trait significantly exceeded non-trait-carriers in DBH activity. This effect is mainly due to the male subjects, confirming the results in the proband groups. Presumably there are common genetic factors that contribute to the variability of both the EEG and DBH.--Taking into account experimental findings on central catecholaminergic activity and EEG synchronization, a hypothesis on the mechanisms that are responsible for the relationship is proposed.

Brain↗