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.

Double moldavites in southern bohemia.

Two noteworthy finds of moldavites were made in southern Bohemia. In both cases two moldavites are thrust into each other. The collision evidently took place during the flight of an inhomogeneous swarm of moldavites, still plastic but already displaying almost definite aerodynamic shapes. It is the first time such moldavites have been encountered, and the authors propose to designate them as double moldavites.

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.

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.

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.

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.

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.

Integrated effects of the vasodilating beta-blocker nebivolol on exercise performance, energy metabolism, cardiovascular and neurohormonal parameters in physically active patients with arterial hypertension.

OBJECTIVE: The present study was designed to investigate the integrated effects of the beta-1-selective blocker with vasodilator properties, nebivolol, on systemic haemodynamics, neurohormones and energy metabolism as well as oxygen uptake and exercise performance in physically active patients with moderate essential hypertension (EH). DESIGN AND METHODS: Eighteen physically active patients with moderate EH were included: age: 46.9 +/- 2.38 years, weight: 83.9 +/- 2.81 kg, blood pressure (BP): 155.8 +/- 3.90/102.5 +/- 1.86 mm Hg, heart rate: 73.6 +/- 2.98 min(-1). After a 14-day wash-out period a bicycle spiroergometry until exhaustion (WHO) was performed followed by a 45-min submaximal exercise test on the 2.5 mmol/l lactate-level 48 h later. Before, during and directly after exercise testing blood samples were taken. An identical protocol was repeated after a 6-week treatment period with 5 mg nebivolol/day. RESULTS: Nebivolol treatment resulted in a significant (P < 0.01) decrease in systolic and diastolic BP and heart rate at rest and during maximal and submaximal exercise. Maximal physical work performance, blood lactate and rel. oxygen uptake (rel. VO(2)) before and after nebivolol treatment at rest and during maximal and submaximal exercise remained unaltered. Free fatty acid, free glycerol, plasma catecholamines, beta-endorphines and atrial natriuretic peptide (ANP) increased before and after treatment during maximal and submaximal exercise but remained unaltered by nebivolol treatment. In contrast, plasma ANP levels at rest were significantly higher in the presence of nebivolol, endothelin-1 levels were unchanged. CONCLUSIONS: Nebivolol was effective in the control of BP at rest and during exercise in patients with EH. Furthermore, nebivolol did not negatively affect lipid and carbohydrate metabolism and substrate flow. The explanation for the effects on ANP at rest remain elusive. This pharmacodynamic profile of nebivolol is potentially suitable in physically active patients with EH.

The athlete's heart. Historical perspectives.

Even an athlete's heart may be affected by clinical conditions. Regarding the extreme performances of the athlete's heart in training and competition, even conditions that might be harmless in sedentary people can be fatal for the athlete. Looking back on the history of the athlete's heart, some common mistakes in its assessment can be avoided that might harm the athlete on the misinterpretation of adaptational phenomena or the trivialization of clinical conditions.

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.

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.

Diagnosis of aseptic necrosis of the talus by bone scintigraphy. Case report.

Bone scintigraphy is a very useful technique for detection of aseptic necrosis. We have used this diagnostic tool in a patient to detect aseptic necrosis of the talus, a common complication stemming from foot injuries. The scintigraphic pattern is rather typical and antedates any other radiographic changes. This technique appears to be very useful for diagnosis and follow-up of aseptic necrosis occurring during talar injuries.

[Sports medicine aspects in children and adolescents]. / Sportmedizinische Aspekte bei Kindern und Jugendlichen.

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.

[Haptic perception and EEG changes in anorexia nervosa]. / Haptische Wahrnehmung und EEG-Veränderungen bei 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.

[The dynamics of the parameters of central nervous activation as a correlate of the motor image]. / Dinamika parametrov tsentral'noi nervnoi aktivatsii kak korreliat dvigatel'nogo obraza.

EEG changes were studied in the case of real movements (wrestlers training) and also in the case of imagination of motor activity (ideomotor training). Statistically significant increases were found of the average frequency of oscillations in the EEG alpha-range and simultaneously typical vegetative changes. Thus, imagination of motor activity may serve as a model for studying the CNS activation processes in connection with the realization of real motor activity.

[Preventing coronary heart disease by physical activity. How much exercise is necessary?]. / KHK-Prävention durch körperliche Aktivität. Wie viel Sport muss sein?

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.

[Phase II ambulatory cardiac rehabilitation (Cologne model). 3 year results after conclusion of the intervention]. / Ambulante kardiale Rehabilitation der Phase II (Kölner Modell). Ergebnisse drei Jahre nach Abschluss der Massnahme.

UNLABELLED: 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.