Monoglyceride Lipase Deficiency Is Associated with Altered Thrombogenesis in Mice

Monoglyceride lipase (MGL) hydrolyzes monoacylglycerols (MG) to glycerol and one fatty acid. Among the various MG species, MGL also degrades 2-arachidonoylglycerol, the most abundant endocannabinoid and potent activator of the cannabinoid receptors 1 and 2. We investigated the consequences of MGL deficiency on platelet function using systemic (Mgl-/-) and platelet-specific Mgl-deficient (platMgl-/-) mice. Despite comparable platelet morphology, loss of MGL was associated with decreased platelet aggregation and reduced response to collagen activation. This was reflected by reduced thrombus formation in vitro, accompanied by a longer bleeding time and a higher blood volume loss. Occlusion time after FeCl3-induced injury was markedly reduced in Mgl-/- mice, which is consistent with contraction of large aggregates and fewer small aggregates in vitro. The absence of any functional changes in platelets from platMgl-/- mice is in accordance with lipid degradation products or other molecules in the circulation, rather than platelet-specific effects, being responsible for the observed alterations in Mgl-/- mice. We conclude that genetic deletion of MGL is associated with altered thrombogenesis.

MFN2 mediates ER-mitochondrial coupling during ER stress through specialized stable contact sites

Endoplasmic reticulum (ER) functions critically depend on a suitable ATP supply to fuel ER chaperons and protein trafficking. A disruption of the ability of the ER to traffic and fold proteins leads to ER stress and the unfolded protein response (UPR). Using structured illumination super-resolution microscopy, we revealed increased stability and lifetime of mitochondrial associated ER membranes (MAM) during ER stress. The consequent increase of basal mitochondrial Ca2+ leads to increased TCA cycle activity and enhanced mitochondrial membrane potential, OXPHOS, and ATP generation during ER stress. Subsequently, OXPHOS derived ATP trafficking towards the ER was increased. We found that the increased lifetime and stability of MAMs during ER stress depended on the mitochondrial fusion protein Mitofusin2 (MFN2). Knockdown of MFN2 blunted mitochondrial Ca2+ effect during ER stress, switched mitochondrial F1FO-ATPase activity into reverse mode, and strongly reduced the ATP supply for the ER during ER stress. These findings suggest a critical role of MFN2-dependent MAM stability and lifetime during ER stress to compensate UPR by strengthening ER ATP supply by the mitochondria.

MICU1 controls cristae junction and spatially anchors mitochondrial Ca2+ uniporter complex

Recently identified core proteins (MICU1, MCU, EMRE) forming the mitochondrial Ca²⁺ uniporter complex propelled investigations into its physiological workings. Here, we apply structured illumination microscopy to visualize and localize these proteins in living cells. Our data show that MICU1 localizes at the inner boundary membrane (IBM) due to electrostatic interaction of its polybasic domain. Moreover, this exclusive localization of MICU1 is important for the stability of cristae junctions (CJ), cytochrome c release and mitochondrial membrane potential. In contrast to MICU1, MCU and EMRE are homogeneously distributed at the inner mitochondrial membrane under resting conditions. However, upon Ca²⁺ elevation MCU and EMRE dynamically accumulate at the IBM in a MICU1-dependent manner. Eventually, our findings unveil an essential function of MICU1 in CJ stabilization and provide mechanistic insights of how sophistically MICU1 controls the MCU-Complex while maintaining the structural mitochondrial membrane framework.

Diacylglycerol triggers Rim101 pathway-dependent necrosis in yeast: a model for lipotoxicity

The loss of lipid homeostasis can lead to lipid overload and is associated with a variety of disease states. However, little is known as to how the disruption of lipid regulation or lipid overload affects cell survival. In this study we investigated how excess diacylglycerol (DG), a cardinal metabolite suspected to mediate lipotoxicity, compromises the survival of yeast cells. We reveal that increased DG achieved by either genetic manipulation or pharmacological administration of 1,2-dioctanoyl-sn-glycerol (DOG) triggers necrotic cell death. The toxic effects of DG are linked to glucose metabolism and require a functional Rim101 signaling cascade involving the Rim21-dependent sensing complex and the activation of a calpain-like protease. The Rim101 cascade is an established pathway that triggers a transcriptional response to alkaline or lipid stress. We propose that the Rim101 pathway senses DG-induced lipid perturbation and conducts a signaling response that either facilitates cellular adaptation or triggers lipotoxic cell death. Using established models of lipotoxicity, i.e., high-fat diet in Drosophila and palmitic acid administration in cultured human endothelial cells, we present evidence that the core mechanism underlying this calpain-dependent lipotoxic cell death pathway is phylogenetically conserved.

Cardiovascular effects of extreme physical training

After a short historical remark the development of athlete's heart in childhood is described. Within 2 years significant differences were observed between endurance-trained (swimming) and untrained girls and boys determined by X-ray and echocardiographical examinations. The limits of the physiological size in relation to body weight were not exceeded within 10 years of longitudinal studies. A second point deals with athlete's heart from physiological and clinical viewpoints. The largest healthy heart ever found in our examinations of athletes had a size of 1,700 ml. Sixteen years after stopping the active career it was reduced to 950 ml without a pathological finding. Questionable and pathological cases are described. A third chapter covers the blood supply of internal organs during exercise combined with air or oxygen breathing. In this connection liver, kidneys, heart, lungs, and brain have been investigated. The reduced blood supply of the liver and kidneys during intense exercise on the cycle ergometer was not influenced significantly by inspiration of oxygen. A significant blood volume increase of the lungs was noticed during incremental rates of work. Exercise augmented also blood flow of the brain in relation to the work rate (at 100 W a 27% increase in grey matter flow of the right hemisphere). A fourth chapter deals with new hormonal and neurohormonal aspects related to the cardiovascular system. Beta-endorphines remained unchanged at work rates below the anaerobic threshold but increased significantly during maximal rate of work. The opiate antagonist naloxone abolished the rise in body temperature seen during ergometer exercise. The serotonin antagonist ketanserin lowered the blood pressure and the arterial lactic acid level during an incremental exercise test, similar to the results with the dopamine agonist pergolide. The hormone cardiodilatin is produced in the atrial appendages, and it is a potent substance in the regulation of the cardiovascular system. The adaptive reaction of the sympathetic nerve fibres in the myocard revealed different directions: activation, degeneration, and regeneration. These findings correlated highly significantly with the total amount of catecholamines in the heart muscle.

Yersinia protein kinase YopO is activated by a novel G-actin binding process

Pathogenic bacteria of the genus Yersinia employ a type III secretion system to inject effector proteins (Yops) into host cells. The Yops down-regulate host cell functions through unique biochemical activities. YopO, a serine/threonine kinase required for Yersinia virulence, is activated by host cell actin via an unknown process. Here we show that YopO kinase is activated by formation of a 1:1 complex with monomeric (G) actin but is unresponsive to filamentous (F) actin. Two separate G-actin binding sites, one in the N-terminal kinase region (amino acids 89-440) and one in the C-terminal guanine nucleotide dissociation inhibitor-like region (amino acids 441-729) of YopO, were identified. Actin binding to both of these sites was necessary for effective autophosphorylation of YopO on amino acids Ser-90 and Ser-95. A S90A/S95A YopO mutant was strongly reduced in substrate phosphorylation, suggesting that autophosphorylation activates YopO kinase activity. In cells the kinase activity of YopO regulated rounding/arborization and was specifically required for inhibition of Yersinia YadA-dependent phagocytosis. Thus, YopO kinase is activated by a novel G-actin binding process, and this appears to be crucial for its anti-host cell functions.

The genome of the social amoeba Dictyostelium discoideum

The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi.

Molecular analysis of aerobic phenylacetate degradation in Azoarcus evansii

The Azoarcus evansii gene which codes for phenylacetate-CoA ligase, an enzyme involved in the aerobic degradation of phenylacetate, was isolated from a genomic library, using as the probe a fragment of the gene which encodes the isoenzyme that is induced under anaerobic conditions. By this means both the gene and its flanking sequences were recovered. The gene is homologous to the phenylacetate-CoA ligase genes of Pseudomonas putida U and Escherichia coli W. Induction by phenylacetate under aerobic growth conditions was demonstrated using lacZ fusions. Western analysis showed that phenylacetate-CoA ligase is involved in the degradation of the aromatic amino acid phenylalanine. Genes coding for the phenylacetate-CoA ligase and for the putative hydroxylating enzyme were expressed in E. coli. Detection of 2-hydroxyphenylacetate in the recombinant E. coli strain indicated hydroxylation of phenylacetyl-CoA. The gene pacL, which codes for the putative ring-opening enzyme was mutated to enable the isolation of intermediates in aerobic phenylacetic acid degradation, which were characterized by GC-MS and NMR analyses.

Characterization of CD36/LIMPII homologues in Dictyostelium discoideum

The CD36/LIMPII family is ubiquitously expressed in higher eukaryotes and consists of integral membrane proteins that have in part been characterized as cell adhesion receptors, scavenger receptors, or fatty acid transporters. However, no physiological role has been defined so far for the members of this family that localize specifically to vesicular compartments rather than to the cell surface, namely lysosomal integral membrane protein type II (LIMPII) from mammals and LmpA from the amoeba Dictyostelium discoideum. LmpA, the first described CD36/LIMPII homologue from lower eukaryotes, has initially been identified as a suppressor of the profilin-minus phenotype. We report the discovery and initial characterization of two new CD36/LIMPII-related proteins, both of which share several features with LmpA: (i) their size is considerably larger than that of the CD36/LIMPII proteins from higher eukaryotes; (ii) they show the characteristic "hairpin" topology of this protein family; (iii) they are heavily N-glycosylated; and (iv) they localize to vesicular structures of putative endolysosomal origin. However, they show intriguing differences in their developmental regulation and exhibit different sorting signals of the di-leucine or tyrosine-type in their carboxyl-terminal tail domains. These features make them promising candidates as a paradigm for the study of the function and evolution of the as yet poorly understood CD36/LIMPII proteins.

ACE and angiotensinogen gene genotypes and left ventricular mass in athletes

BACKGROUND

Genetic factors may be important in modifying heart size due to long-term athletic training. The significance of polymorphisms of genes of the renin-angiotensin system in myocardial mass in a population of athletes participating in different disciplines is not known.

METHODS

The angiotensin I-converting enzyme gene insertion/deletion (I/D) polymorphism, angiotensinogen gene M235T polymorphism and angiotensin II type 1 receptor gene A1166C polymorphism were determined in 83 male Caucasian endurance athletes and associated with left ventricular mass.

RESULTS

No association with left ventricular mass was found for the polymorphisms of angiotensin I-converting enzyme gene I/D, angiotensinogen gene M235T and angiotensin II type 1 gene A1166C when studied separately. However, combined analysis of the angiotensin I-converting enzyme gene I/D polymorphism and angiotensinogen gene M235T polymorphism genotypes suggested an association with left ventricular mass (g m(-2)) (P = 0.023). Athletes with the angiotensin I-converting enzyme gene DD/angiotensinogen gene TT genotype combination had greater left ventricular mass compared with all other genotype combinations (179.8 +/- 26.1 g m(-2) vs. 145.2 +/- 27.3 g m(-2), P = 0.003).

CONCLUSIONS

These results suggest an association of combined angiotensin I-converting enzyme gene I/D polymorphism genotypes, and angiotensinogen gene M235T polymorphism genotypes with left ventricular hypertrophy due to long-term athletic training. A synergistic effect of angiotensin I-converting enzyme gene DD genotype and angiotensinogen gene TT genotype on left ventricular mass in endurance athletes appears to occur.

Theta power in the EEG of humans during ongoing processing in a haptic object recognition task

Dynamic changes in spectral theta power (TP) in the EEG over frontal regions were reported previously during the processing of visually presented spatial and verbal tasks [Cereb. Cortex, 7 (1997) 374-385]. Lower TP was found at the beginning compared to the end of processing. In order to test another modality, we examined theta power during the exploration of haptic stimuli with different complexity. A linear correlation between theta power and mean exploration time (as a measure of stimulus complexity) was found at the end of exploration but not at its beginning. These data are in line with our hypothesis since one could expect minimal load of working memory independent of stimulus complexity at the beginning of exploration whereas working memory would have integrated the stimuli of differing complexity into a perceptual model at the end of exploration.

[Preventing coronary heart disease by physical activity. How much exercise is necessary?]

The value of general measures, in particular physical exercise, for the prevention of cardiac disease has been unequivocally demonstrated. Meta-analyses done to investigate the preventive character of exercise have shown that the coronary risk of physically active persons is lower by a factor of 2 to 3. This reduction in risk is independent of the presence of other risk factors, and is not due to the better health awareness of those who are physically active. However, the amount or intensity of such training actually required remains uncertain. A number of studies report a protective effect only for intensive physical effort, while others claim a risk reduction independent of training intensity. In the last resort, however, any form of exercise is better than none at all, when it comes to lowering the coronary risk. Not only endurance sports, but also other types of sport, such as tennis, or daily activities, can be recommended.

Patients with dilated cardiomyopathy and less than 20% ejection fraction increase exercise capacity and have less severe arrhythmia after controlled exercise training

The results of this pilot study suggest that patients with a diminished ejection fraction as low as 16% can safely perform an exercise program. A significant improvement in peak VO2 and maximal work rate was achieved. Moreover, this study suggests that exercise training might diminish the severity of asymptomatic ventricular arrhythmia; however a larger controlled study is needed to confirm these findings.

[Haptic perception and EEG changes in anorexia nervosa]

OBJECTIVES

We predicted that due to diminished somatosensory integrative ability, the anorectic patients would have problems reproducing haptic stimuli. In addition we sought to determine whether EEGs from anorectic patients (AN) and the healthy controls (CO) would show discrepancies between the two groups during haptic explorations in theta-power over the right parietal region.

METHOD

EEG power (theta-power) data of AN (n = 13) and CO (n = 13) were analyzed during haptic exploration tasks and rest intervals. The haptic explorations consisted of palpating the structure of six sunken reliefs in sequence with both hands, eyes closed. After each exploration the structure was drawn on a piece of paper.

RESULTS

The reproductions of haptic stimuli submitted by the anorectic patients were of notably poorer quality than those of the healthy controls. During rest intervals and haptic explorations, spectral power was generally lower in the AN group in comparison to the healthy controls. Significant theta-power differences between groups showed over the right parietal cortex during haptic explorations. The decrease in EEG power in the anorectic patients in the theta bands across the right parietal region during haptic exploration tasks could be interpreted as a minor activation of visuo-spatial regions. The results of the haptic explorations as well as the EEG-power changes indicate a cortical dysfunction and deficits in somatosensory integration processing in anorexia nervosa patients.

[Phase II ambulatory cardiac rehabilitation (Cologne model). 3 year results after conclusion of the intervention]

BASELINE: Of a total of 101 patients with CAD who participated in an ambulatory cardiac rehabilitation program (ACR) ("Cologne model") between 1992 and 1994, 76 (75.2%) were examined 36 months after concluding ACR.

RESULTS

The significant improvement in exercise tolerance from 118.4 +/- 30.1 to 131.9 +/- 34.1 W achieved with the ACR was maintained at the 3-year examination. ACR also significantly decreased plasma cholesterol levels from 228.9 +/- 48.3 to 211.7 +/- 37.0 mg%; 3 years after ACR the corresponding figures were 219.1 +/- 39.3 mg%. In the high-risk group the significant reduction in plasma cholesterol levels from 265 +/- 43.6 to 231.9 +/- 35.4 mg% observed immediately after ACR was maintained over the three-year period (234.6 +/- 37.7 mg%). Similar patterns were observed for other parameters of lipid metabolism. Before the cardiac event 63.2% of the patients smoked; at the 3-year examination the percentage was 30.3%. Before ACR, 73.7% of the patients were gainfully employed. Within the first 6 months after ACR, 71.4% returned to work, and this percentage increased to 73.2% after one year. Three years later, 64.3% were still working.

DISCUSSION

The results demonstrate that the lifestyle changes achieved with 4-weeks of ACR may, at least in part, be maintained over a period of 36 months.

Reduction of the plasma concentration of C-reactive protein following nine months of endurance training

An intense physical exercise induces an inflammatory reaction as demonstrated by the delayed increase in blood of acute phase proteins and among them of C-reactive protein (CRP). There is also evidence for a diminished acute phase reaction due to regular exercise suggesting a suppression of the inflammatory response through training. With this background CRP was measured by a sensitive enzyme immunoassay under resting conditions before and after 9 months of training in 14 subjects preparing for a marathon with the aim of studying the effect of training on the base-line CRP concentration. The mean distance run per week increased significantly from 31 +/- 9 km at the beginning to 53 +/- 15 km after 8 months of training (p < 0.01). The aerobic capacity rose significantly after training as demonstrated by the increase of running velocity during a maximal treadmill test from 3.82 +/- 0.29 m/s pre-training to 4.17 +/- 0.17 m/s post-training at a blood lactate concentration of 4 mmol/L (p < 0.01). In 10 of 12 runners base-line CRP was diminished after training in spite of a continuous increase of training intensity. The CRP median fell from 1.19 mg/L before to 0.82 mg/L after training (p < 0.05). Since intense physical exercise is known to be associated with an inflammatory reaction of muscles and tendons, the CRP decrease was unexpected. In 2 subjects the CRP concentration rose markedly because of a borrelia infection and a knee injury, respectively. These values were caused by a pathological condition and were not considered for the statistical evaluation. In 10 non-training control subjects the CRP median did not change significantly during the same 9 months period. The decrease of the CRP base-line concentration after training suggests that intensive regular exercise has a systemic anti-inflammatory effect. This is of particular interest with regard to several recent reports confering on the concentration of CRP in plasma a predictive value for the risk of cardiac infarction, venous thrombosis or stroke.

[Haptic perception and EEG changes in anorexia nervosa]

OBJECTIVES

We predicted that due to diminished somatosensory integrative ability, the anorectic patients would have problems reproducing haptic stimuli. In addition we sought to determine whether EEGs from anorectic patients (AN) and the healthy controls (CO) would show discrepancies between the two groups during haptic explorations in theta-power over the right parietal region.

METHOD

EEG power (theta-power) data of AN (n = 13) and CO (n = 13) were analyzed during haptic exploration tasks and rest intervals. The haptic explorations consisted of palpating the structure of six sunken reliefs in sequence with both hands, eyes closed. After each exploration the structure was drawn on a piece of paper.

RESULTS

The reproductions of haptic stimuli submitted by the anorectic patients were of notably poorer quality than those of the healthy controls. During rest intervals and haptic explorations, spectral power was generally lower in the AN group in comparison to the healthy controls. Significant theta-power differences between groups showed over the right parietal cortex during haptic explorations. The decrease in EEG power in the anorectic patients in the theta bands across the right parietal region during haptic exploration tasks could be interpreted as a minor activation of visuo-spatial regions. The results of the haptic explorations as well as the EEG-power changes indicate a cortical dysfunction and deficits in somatosensory integration processing in anorexia nervosa patients.

[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)

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.

[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.

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.

[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.

[Need for ambulatory cardiology after-care rehabilitation in the metropolitan area of a large city. Results of the Cologne model of ambulatory cardiologic rehabilitation--phase II]

Within the Cologne Model (CM) of outdoor cardiac rehabilitation (OCR), phase II investigations about the demand for this form of cardiac rehabilitation (CR) after acute cardiac diseases were carried out in three general hospitals, the cardiological and cardiosurgical university hospitals of Cologne. The subsequent questions were investigated: total number of coronary or cardiac operated patients, number of patients with indication for CR, and number of patients corresponding to the restricted indications of CM (age below 65, low risk patient, no cardiac operation). For these groups the acceptance or refusal of CR was checked. Subsequently a sample of patients corresponding to the criteria of CM or of operated patients were confronted with the additional offer of an OCR. The motivation for the acceptance of rehabilitation in specialized hospitals (ICR), OCR or refusal of each kind of CR was inquired. The acceptance of CR in the different groups varied widely. Whereas operated patients in Cologne accept CR in nearly 100% of cases, this is the case in patients after acute myocardial infarction (AMI) in only 50% and in patients after PTCA without AMI in only 5-6%. The analysis of predictors for acceptance brings about that younger patients prefer CR, and if they do, OCR. Patients with the more serious form of disease prefer ICR. Women accept CR more rarely than men, and if they do, they prefer the hospital form. However, this is less gender specific but consequence of the generally more serious form and later onset of CAD in females. Higher educational as well as occupational status favors acceptance of CR and specially OCR. The suspicions that unmarried people prefer OCR and foreigners ICR could not be generally confirmed. Crucial reasons for the form of CR which is accepted or refused are individual ones. ICR is favored by the wish for more safety and better recuperation. For OCR, the comfortable conditions at home with high social support and/or antipathy against hospitals after long clinical treatment are named. Analysis of demand for OCR demonstrates that between 40% in low risk patients (corresponding to CM criteria) and 20% in more serious cases (operated patients) prefer the outhospital form. From these data an estimation of demand for OCR in areas with high population was carried out.

[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.

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.

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.

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.

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.

[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.

[The microagglutination test--a simple and sensitive procedure for serodiagnosis of pertussis infections]

The microagglutination assay is a useful method for the diagnosis of B. pertussis infections. In a group of 30 patients with culture proven pertussis 27 (90%) had > or = fourfold increases in titers between acute and convalescent phase serum specimens. The microagglutination test offers several advantages over other more sophisticated B. pertussis antibody tests: only 50 microliters of serum is required, it is a standardized test, which doesn't require specialized technical expertise or equipment, it is easy to perform and good results are noted in a broad age range of patients. Disadvantages of the microagglutination test are: two separate serum specimens are necessary (acute and convalescent phase), the test does not differentiate IgA and IgG antibodies and the temporal association with recent immunization can lead to false positive results. In our opinion the microagglutination test is a useful method for the diagnosis of B. pertussis infections. This is especially true in cases where more sophisticated serologic tests such as ELISA can not be performed immediately but physicians and patients expect to get a result quickly.

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.

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.

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.

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.

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.

Effects of simulated microgravity (HDT) on blood fluidity

Exposures to microgravity and head-down tilt (HDT) produce similar changes in body fluid. This causes an increase in hematocrit that significantly affects hemorheological values. Lack of physical stimulation under bed rest conditions and the relative immobility of the crew during spaceflight also affects the blood fluidity. A group of six healthy male subjects participated as volunteers, and blood samples were collected 10 days before, on day 2 and day 9, and 2 days after the HDT phase. Blood rheology was quantified by plasma viscometry, red cell aggregability, and red cell deformability. A reduced red cell deformability, an indication of the diminished quality of the red blood cells, was measured under HDT conditions that finally led to the so-called "space flight anemia." Enhanced red cell membrane fragility induced by diminished physical activity and an increase in hemoglobin concentration are responsible for this effect. Plasma viscosity is reduced as a result of diminished plasma proteins. However, despite the reduction in plasma proteins, including fibrinogen, alpha 2-macroglobulin, and immunoglobulin M, red cell aggregation was enhanced, principally because of the increase in hematocrit. Our results of hemorheological alterations under HDT conditions may help to elucidate the formerly documented hematologic changes during spaceflight.