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Biomedical subjects

R Rost

Publications and source records attributed to R Rost.

At least 19 recordsLinked to original sources
PubMed1999

Power of theta waves in the EEG of human subjects increases during recall of haptic information.

Several studies have reported a functional relationship between spectral power within the theta-band of the EEG (theta-power) and memory load while processing visual or semantic information. We investigated theta power during the processing of different complex haptic stimuli using a delayed recall design. The haptic explorations consisted of palpating the structure of twelve sunken reliefs with closed eyes. Subjects had to reproduce each relief by drawing it 10 s after the end of the exploration. The relationship between mean theta power and mean exploration time was analysed using a regression model. A linear relationship was found between the exploration time and theta power over fronto-central regions (Fp1, Fp2, F3, F7, F8, Fz, C3) directly before the recall of the relief. This result is interpreted in favour of the hypothesis that fronto-central theta power of the EEG correlates with the load of working memory independent of stimulus modality.

Adolescent↗
PubMed1999

[Ambulatory cardiac phase II rehabilitation--"the Cologne model"--including 3-year-outcome after termination of rehabilitation].

From January 1992 until December 1994 the Cologne model of ambulant cardiac rehabilitation (ACR) in the greater area of Cologne, Germany, was performed and is still in progress. In Germany until 1992 the cardiac rehabilitation was exclusively performed stationary. The objective of the "Cologne model" was to evaluate, whether the transfer of the stationary cardiac rehabilitation programs into the ambulatory setting is achievable without deficits in efficiency, safety and overall quality. The results obtained are intended to serve for standardization and quality control of future ambulatory cardiac rehabilitation programs in Germany. From 1992 to 1994 108 patients (94 men, 14 women; 52.3 +/- 8.0 years old) with coronary artery disease (CAD) which were compatible with the criteria of the "Cologne model" (Table 1) participated in the 4-week ACR. The indications for inclusion into the ACR were in 74 cases a myocardial infarction (MI), in 34 cases CAD without MI, but with PTCA/stent-procedure (Table 3). Seven patients discontinued the ACR prematurely, 2 patients because of cardiovascular reasons. Reasons for the preference of the ambulatory over a stationary cardiac rehabilitation program were in 40.6% of the patients refusal of "hospital ambience", in 43.6% familiar or in 12.9% professional reasons. During the 4-week ACR patients participated in a mean of 72.9 +/- 6.7 hours of therapy (Table 4). As a result of the ACR exercise tolerance increased highly significantly (**) from 116.4 +/- 28.8 to 129.9 +/- 34.6 watt). This improvement was maintained at the 1- and 3-year control (128.7 +/- 35.8**) examinations (Tables 5 and 7). One year after ACR 77% of the patients stated to be physically active in ambulatory heart groups (AHG) (27.6%) or on their own (49.4%). Three years after ACR the rate of regularly physically active patients still was 59.2%. Furthermore, as a result of ACR the dietary behavior was changed significantly. There was a reduction in the consumption of lipids by 20.8%, saturated fatty acids by 30.7% and of cholesterol by 30.5%. The plasma concentrations of cholesterol decreased from 231 +/- 49.8 to 213.2 +/- 35.9 mg%**. Six (and 12) months after ACR they increased again to 225.6 +/- 39.4 mg%. Three years after ACR the mean cholesterol level was 219.1 +/- 39.3 mg%. In the high risk group (cholesterol at the initial visit > 220 mg%) cholesterol levels were reduced from 266 +/- 44 to 232 +/- 31.9 mg%**. Six and 12 months after ACR they were 239.7 +/- 35.8 mg% and 245.8 +/- 32.6 mg%, respectively, (Tables 6 and 7) and still significantly lower than before ACR, though only 19% of the patients were treated with lipid lowering agents. Three years after ACR cholesterol were 234.6 +/- 37.7 mg%** in the high-risk group. 34.2% of the patients received lipid lowering agents. Mean body weight remained unaltered over the 3-year period. Smoking behavior was not altered significantly during the 4-week ACR. However, before the cardiovascular event 67.3% of the patients had smoked cigarettes. At the beginning and at the end of ACR 20.8% of the patients still smoked. During the ACR the number of smoked cigarettes was reduced significantly from 32.4 +/- 15.2 to 6.9 +/- 5.2 cigarettes per day. One year after ACR 23% of the patients were smokers, 3 years after ACR the percentage of smokers increased to 30.3%. Before ACR 73.3% of the patients were still working. During the first 6 months after ACR 68.2% returned to work and the percentage increased to 73% in the following 6 months. The results demonstrate that it is achievable to transfer the contents of the established stationary cardiac rehabilitation programs into the ambulatory setting without loss of efficiency, safety and overall quality. It is further confirmed, that it is necessary to continuously evaluate the results of the cardiac rehabilitation program on a long-term basis. (ABSTRACT TRUNCATED)

Adult↗
PubMed1999

[Clinical follow-up 6 months after ambulatory/partial inpatient after-care rehabilitation. Further results of the Cologne model of ambulatory cardiac phase II rehabilitation].

Three hundred and thirty patients with coronary artery disease (CAD) (288 men, 42 women, age of 55.5 +/- 10.0 years) participated in a 4-week ambulatory cardiac rehabilitation program (ACR) (Table 1). The cardiovascular indication for ACR was in 229 cases a myocardial infarction. In 101 patients a CAD with invasive revascularization but without a history of MI was present. In 92 patients with myocardial infarction additionally an invasive revascularization was performed. Eighty-three patients were included after a CABG-procedure (Tables 2 to 5). Six months after the ACR 290 (87.9%) patients presented for clinical reevaluation. In 235 (81.0%) of the 290 examined patients the cardiovascular diagnosis was unaltered. In the first 6 months after ACR in 76 (26.2%) patients a coronarography was performed, in 44 patients a restenosis was diagnosed. In 36 patients an additional invasive procedure (in 28 patients a PTCA, in 5 patients with additional stent-implantation, in 1 case with rotablation, in 8 patients CABG) was performed. In 1 patients a pace-maker was implanted. Since the ACR 1 patient experienced a myocardial infarction and 2 a recurrent myocardial infarction. In 1 patient myocardial fibrillation occurred. Totally, 70 patients (24.1%) required stationary-hospital treatment during the first 6 months after ACR (Table 6). In 11 cases an acute admission to hospital treatment because of cardiovascular reasons was documented. The majority of the hospital admission was elective, because of diagnostic or therapeutic procedures. In 6 patients a CABG-surgery was performed. In approximately 80% of the patients the cardiovascular status was stable during the first 6 months after ACR. Though 24.1% of the patients required stationary hospital treatment, the majority of the admissions was elective of interest, there was a high rate of hospital admissions in the PTCA-group in combination with recoronarographies and revascularization because of early reocclusion.

Adult↗
PubMed1999

[Improvement of physical performance and aerobic capacity mediated by a novel 4--week ambulatory cardiac rehabilitation program].

During a 4-week ambulatory cardiac rehabilitation program, 262 patients with coronary artery disease (CAD), 235 men and 27 women, 53.6 +/- 10.2 years, performed 30.5 +/- 2.9 exercise units. Before and after the rehabilitation program exercise, capacity was assessed by bicycle ergometry. There was a significant (p < 0.001) increase in the maximum exercise capacity at the end of the program (105.3 +/- 32.3 vs. 121.9 +/- 37.3 W). Physical work capacity on the 2.0 mmol lactate level improved (p < 0.001) from 72.2 +/- 23.5 to 86.4 +/- 25.8 W, on the 2.5 mmol/l level (p < 0.001) from 83.5 +/- 23.2 to 97.4 +/- 26.4 W, and on the 3.0 mmol/l level (p < 0.001) from 93.1 +/- 23.0 to 106.6 +/- 26.1 W. Despite enhanced performance, heart rate remained unaltered on the 2.0, 2.5, and 3.0 mmol/l lactate level. Furthermore, ergometric performance on predefined heart rate levels was significantly (p < 0.001) increased: 85/min: from 56.0 +/- 24.1 to 65.8 +/- 24.5 W, 90/min: from 62.0 +/- 27.3 to 71.2 +/- 26 W; 95/min: from 67.2 +/- 26.4 to 77.5 +/- 27.6 W; 100/min: from 71.1 +/- 29.6 to 80.6 +/- 28.1 W; 105/min: from 69.8 +/- 26.2 to 81.9 +/- 28.2 W and 110/min: from 73.6 +/- 28.9 to 90.4 +/- 29.4 W. The results demonstrate that physical performance in patients with CAD was improved by our novel ambulatory cardiac rehabilitation program. This improvement included an increase in maximum as well as endurance work capacity; furthermore, this increase was accompanied by a decrease in resting and exercise heart rates. The results demonstrate an absolute increase of physical performance, more importantly an increase of physical performance at defined lactate levels in the presence of unchanged heart rates mediated by the rehabilitation program. Thus, this increase was independent of motivational factors in the patients and/or the investigators during the re-exercise test. On the contrary, our data demonstrate that it is based on an improvement of aerobic endurance capacity associated with a therapeutically beneficial significant decrease of heart rate for a defined workload. The effects were independent of pharmacological influences (e.g., beta-receptor antagonists). These findings are of clinical importance with respect to reduction of myocardial oxygen consumption in patients with CAD.

Coronary Disease↗
PubMed1999

Neuroendocrine system and mental function in sedentary and endurance-trained elderly males.

Hypothalamic-pituitary-adrenal (HPAA) and -gonadal (HPGA) axis modification and cognitive impairments have been reported in elderly subjects and related to physical training status. The aim of this study was to investigate if HPAA and HPGA regulation are altered in elderly distance runners (RUN; n = 8; age: 68.9+/-4.2 yrs; training: 65+/-20 km/wk over the last 20 yrs; means +/- SD) or are affected in elderly sedentary individuals (SED; n = 11; age: 69.1+/-2.6 yrs) by an aerobic training over 20 weeks (3 times/week, 30-60 min walking), respectively. The protocol included assessment of the hormone profile in basal non-suppressed state as well as evaluation of hormonal responses to dexamethasone (DEX, 1.5 mg) induced adrenal suppression, to post-DEX combined corticotrophin releasing hormone (CRH; 0.7 microg/kg) and luteinizing hormone releasing hormone (LHRH, 0.7 microg/kg) stimulation and to exercise challenge (30 min cycle ergometry at 65% VO2max). Mental functions influenced by HPAA and HPGA activity were also assessed in RUN and SED before (SED-PRE) and after (SED-POST) the training program. Basal and post-DEX plasma concentrations of adrenocorticotropic hormone (ACTH), cortisol (CSL), luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone (T) did not differ between RUN and SED-PRE. Basal plasma free T concentration was significantly lower in RUN (RUN: 10.23+/-2.41 pg x ml(-1) vs. SED-PRE: 16.6+/-5.59 pg x ml(-1)). During releasing hormone challenge test after DEX administration (DEX/RH), no differences were found between RUN and SED-PRE in plasma ACTH, LH, FSH and T response. During this stimulation test, plasma CSL was significantly higher in RUN than in SED-PRE after 90 min (RUN: 5.86+/-3.65 microg x dl(-1) vs. SED-PRE: 2.74+/-2.09 microg x dl(-1)). Differences in plasma CSL concentrations between groups were not induced by 30-min exercise challenge. Basal hormone profile was not altered by training in SED. During DEX/RH only plasma ACTH concentration was significantly higher in SED-POST compared to SED-PRE. Long and short-term memory function did not differ between RUN, SED-PRE and SED-POST. Our data suggest that following post-DEX CRH/LHRH challenge elderly endurance athletes reveal-in the absence of altered peak values-a pattern of prolonged secretion of glucocorticoids. However, the high interindividual variability of plasma ACTH and CSL concentrations shows that reduced corticotropic sensitivity to negative feedback is not always induced by chronic exercise stress. Lower plasma free T concentrations in RUN compared to SED are not caused by modified LH synthesis-secretion capacity.

Adrenocorticotropic Hormone↗
PubMed1998

Hypothalamic-pituitary-adrenal and -gonadal axis function after exercise in sedentary and endurance trained elderly males.

The aim of this study was to investigate hypothalamic-pituitary-adrenal (HPAA) and -gonadal (HPGA) axis responses to post-exercise (30 min at 65% VO2max) combined corticotrophin, luteinizing hormone and thyrotrophin releasing hormone challenge (0.7 microg/ kg body mass) in elderly distance runners (DR; age: 68.9+/-4.2 year) and sedentary individuals (SI; age: 69.1+/-2.6 year). Plasma cortisol, growth hormone, prolactin, luteinizing hormone, follicle stimulating hormone and total testosterone (T) concentrations pre- and post-exercise as well as in response to stimulation did not differ between DR and SI. Plasma adrenocorticotropic hormone returned to pre-exercise level in DR 60 min and in SI 90 min post-stimulation. Free T was lower in DR at all time points. Our results do not support the notion of altered releasing hormone-stimulable HPAA and HPGA synthesis-secretion capacity in elderly males after endurance training.

Adrenal Glands↗
PubMed1998

[Sports medicine aspects in children and adolescents].

In opposite to adults, exercise and sports are natural elements in the life of children and adolescents. However, they gain new aspects in the modern achievement-oriented society. The competitive sports are moving more and more towards the children's and adolescents's age. Additionally, sport should be done early during live for prevention of civilization diseases later on. Finally, physical therapy gains growing importance in the therapy and rehabilitation of children and adolescents. As to strength, children are not just 'small adults'. In children, the physical capacity in the aerobic range is larger and in the anaerobic range is smaller than in adults. The question of trainability and talent, respectively, plays an important role in the competitive sport as well as in the consultation of children for their sport career. The danger of the child during sport is discussed from the view of internal and orthopedic medicine. Concepts of sports medical preventions are derived from this discussion. The question of sports with pre-existing diseases in children and adolescents is only marginally discussed.

Adolescent↗
PubMed1997

The athlete's heart. Historical perspectives--solved and unsolved problems.

Clinicians are coming back to Henschen's assessment of the athlete's heart as a physiologic and positive phenomenon. An athlete's heart may be affected by clinical conditions. Regarding the extreme performance of the athlete's heart in training and competition, conditions that may be harmless in sedentary people can be fatal for the athlete. The athlete's heart therefore deserves the particular interest and care of the sports cardiologist.

Adaptation, Physiological↗
PubMed1997

Blood glutathione status following distance running.

In 12 moderately trained subjects reduced glutathione (GSH) and oxidized glutathione (GSSG) as well as thiobarbituric acid reactive substances (TBARS) were measured in the blood before and during the first two hours and first two days after a 2.5-h run. The participants covered between 19 and 26 km (20.8 +/- 2.5 km, mean +/- SD). The running speed was between 53 and 82% of the speed at which blood lactate concentration reached 4 mmol/L lactate (67.9 +/- 8.2%, mean +/- SD) assessed during a previously performed treadmill test. Blood samples were collected 1 h before, immediately before, immediately after, 1 and 2 h after, as well as 1 and 2 days after the run. Immediately after exercise GSH was significantly decreased (p < 0.01) and GSSG significantly increased (p < 0.01). In all subjects the ratio of GSH to GSSG showed a marked decline to 18 +/- 4% (mean +/- SD) of the pre-exercise values (p < 0.01). One hour later the mean GSH and GSSG values returned to baseline. However, there were considerable inter-individual differences. In some subjects the GSH/ GSSG ratio overshot the pre-exercise levels, in others the ratio remained low even two hours after exercise. Compared with the pre-exercise values TBARS concentrations did not change significantly at any time point after exercise. The findings suggest that after prolonged exercise in moderately trained subjects a critical shift in the blood glutathione redox status may be reached. The changes observed were generally short-lived, the duration of which may have depended on the relative importance of reactive oxygen species generation by the capillary endothelial cells and neutrophil and eosinophil granulocytes after the end of exercise.

Adult↗
PubMed1997

Assessment of isometric contractions performed with maximal subjective effort: corresponding results for EEG changes and force measurements.

In order to find a parameter or parameters that can be attributed to movements performed with maximal subjective effort, EEG recordings and force measurements were taken in connection with isometric muscle contractions performed with 80% of the subjective maximal force (IMC80) or with maximal subjective effort (IMC100). Criteria based on EEG recordings and force measurements have been considered as indicators for maximal subjective effort in a given movement. The following criteria were selected: A. If the mean spectral theta amplitude across the parieto-occipital area decreases from IMC80 to IMC100 then the isometric contraction is taken to be performed with maximal effort; B. If the obtained force values can be fitted to a switch function and if the achieved forces are only a predetermined percentage lower than the maximal force value obtained over all trials then this isometric contraction is accepted to be performed with maximal effort. 18 out of 24 cases fulfill the EEG criterion whereas the criterion for force measurements is fulfilled in 16 out of 24 trials. The comparison between the results obtained by means of the EEG criterion and by means of criterion for force measurement shows that the results are in agreement in 22 out of 24 cases (p < .001). The high correspondence of the assessments allows us to suspect that both criteria specify the same phenomenon, namely the performance of a motor task with maximal subjective effort.

Adult↗
PubMed1996

[Effect of low dose omega-3 fatty acid supplementation on plasma lipids and lipoproteins in coronary patients with dyslipoproteinemia].

In a prospective study, 20 patients (aged 48-67 years) with primary hyperlipoproteinaemia of phenotypes IIa, IIb, IV and with proven coronary sclerosis received four different doses of long-chain polyunsaturated omega-3 fatty acids. 0.18 to 1.1 g per day were administered in the form of fish oil capsules over four 2-week periods. The aim was to study the effect of different low dose supplementations of n-3 fatty acids on the plasmalipid- and lipoprotein composition and to determine a threshold of effectiveness. Significant reduction of the triglyceride level was registered in all subjects with the greatest decrease in those patients who presented with the highest base levels. The cholesterol and LDL-cholesterol values on average remained almost unchanged, apart from a significant increase of LDL-cholesterol in patients with type IV hyperlipoproteinaemia. The HDL-cholesterol fraction also showed a significant increase in type IIb patients which was related to alterations of the HDL-3 subfraction. The minimal effective dose of a daily administration of omega-3 fatty acids can be expected between 0.18 g and 0.35 g. The observed changes of plasmalipids and lipoproteins reflect the beneficial effect of long-chain polyunsaturated omega-3 fatty acids in respect to plasma-triglyceride reduction and HDL-cholesterol increase as seen in other studies, despite the use of supplementations far below 1 g per day.

Aged↗
PubMed1995

Theta power decreases in preparation for voluntary isometric contractions performed with maximal subjective effort.

In order to find EEG parameters that can be attributed to movements performed with maximal subjective effort, EEG recordings and force measurements were realized in connection with isometric contractions (IMC). IMC were performed with submaximal and maximal subjective effort. Mean spectral power density within the theta band was found as an indicator for maximal subjective effort. The theta power across the parieto-occipital area decreases from rest through movements performed with submaximal force to movements performed with maximal effort. It is argued that this theta decrease possibly reflects a down-regulation of the posterior attention system in order to minimize the influences of external stimuli during the preparation for voluntary IMC performed with maximal subjective effort.

Adult↗
PubMed1994

Activation processes during mental practice in stroke patients.

In healthy subjects, mental practice is known to improve motor performance. It is also known to be accompanied by a higher central nervous activity. Since such effects seem to be desirable for rehabilitation, we investigated the possibility of detecting changes in central nervous activity by means of EEG in stroke patients, and whether these changes were similar to those observed in healthy subjects. 12 left-sided hemiplegic patients who underwent a specific post-stroke rehabilitation treatment were requested to perform a simple arm movement sequence. In the following mental practice period the patients were requested to image the same sequence without any real movement. EEG background activity was recorded during rest and imagination periods. After the calculation of z-transformed power values within the theta, alpha, and beta-1 band, differences between rest and imagination periods were evaluated for their significance. Stroke patients show significant decreases of theta, alpha, as well as beta-1 power during mental practice in comparison to the rest period. These changes are similar to those obtained in healthy subjects. Theta power decreases in central and parietal leads. Central alpha power diminishes only during imagination of the contralateral arm. This phenomenon as well as the decrease of beta-1 power in central derivation were also obtained during real motor performance and might indicate an activation of the sensorimotor cortex. In accordance with the hypothesis of internal feedback mechanisms, this activation is a necessary prerequisite for motor learning during mental practice.

Aged↗
PubMed1994

Clinical characteristics of illness caused by Bordetella parapertussis compared with illness caused by Bordetella pertussis.

In conjunction with a pertussis vaccine efficacy trial in Germany, nasopharyngeal specimens were collected from May, 1992, to March, 1993, from patients with cough illnesses. Clinical data were obtained by initial and follow-up questionnaires. Bordetella parapertussis was isolated from 38 patients (mean age, 3.5 years; 68% girls). Clinical characteristics in these cases were compared with those of 76 patients (matched by age and sex) with illness caused by Bordetella pertussis during the same period. Findings were: (B. pertussis/B. parapertussis): cough > 4 weeks 57%/37% (P = 0.06); whoop 80%/59% (P = 0.07); whoop > 2 weeks 26%/18% (P = 0.05); paroxysms 90%/83% (P = 0.5); body temperature > or = 38 degrees C 9%/0% (P = 0.17); vomiting 47%/42% (P = 0.69); and mean leukocyte and lymphocyte counts 12,500/mm3 and 7600/mm3 (P < 0.0001) and 7800/mm3 and 3500/mm3 (P < 0.0001), respectively. Illness caused by B. parapertussis was typical of pertussis but less severe than that caused by B. pertussis. In contrast with B. pertussis infection, lymphocytosis is not a characteristic of B. parapertussis infection. This is most likely a result of the lack of production of lymphocytosis-promoting factor toxin by B. parapertussis.

Bordetella↗
PubMed1994

Mental practice of motor skills used in poststroke rehabilitation has own effects on central nervous activation.

In the last years it has been shown that the use of the EMG triggered electrical myostimulation (ETEM) brings good results in poststroke rehabilitation. It has been hypothesized that the relearning effects obtained by means of ETEM are due to the reinstatement of proprioceptive feedback. However, the technique is most powerful if imagination of motor acts (the so called mental practice) is used as an initial part of ETEM. Since mental practice in healthy people leads to central nervous activation processes as well as to an improvement of motor skills, we investigated the effects of mental practice alone on central nervous activity by means of EEG in stroke patients. Twelve left-sided hemiplegic patients who underwent a specific poststroke rehabilitation treatment were requested to perform a simple arm movement sequence. In the following mental practice period the patients were requested to imagine the same sequence without any real movement. EEG background activity was recorded during baseline and imagination periods. After the calculation of z-transformed power values within the alpha and beta-1 band, differences between rest and imagination periods were evaluated for significance. Stroke patients showed significant decreases of alpha as well as beta-1 power during mental practice in comparison to the rest period. These changes are similar to those obtained in healthy subjects. Central alpha power diminished only during imagination of the contralateral arm. This phenomenon as well as the decrease of beta-1 power in central derivation were also obtained during real motor performance and might indicate an activation of the sensorimotor cortex. In accordance with the hypothesis of internal feedback mechanisms, this activation is a necessary prerequisite for motor learning during mental practice. We conclude that mental practice of motor skills might have own effects in poststroke rehabilitation.

Aged↗
PubMed1993

Effect of a short maximal physical exercise on the eosinophil cationic protein.

Eosinophil cationic protein (ECP) has been shown to be a marker of eosinophil granulocyte activation. In 10 healthy young subjects the plasma concentrations of ECP were measured before and after a graded maximal bicycle exercise test. The analyses were carried out 30 min before and immediately before exercise, immediately after exercise and 20 and 45 min later. The post-exercise values were corrected for plasma volume changes which were calculated from hematocrit and hemoglobin values. Immediately post-exercise the ECP increased significantly (p < 0.01) from 1.25 +/- 0.28 at rest to 2.40 +/- 0.59 micrograms/l. Twenty and 45 min later the values normalized and significant differences from the pre-exercise values could no longer be measured. The results provide strong evidence for an activation of eosinophil granulocytes after a short maximal exercise.

Adult↗