One- and two-dimensional echocardiography in bodybuilders using anabolic steroids

The object of this study was to investigate the possible concentric increase in the left ventricular (LV) wall thickness by intensive strength training and to differentiate between the specific effect of the strength training itself and the influence of anabolic drugs. In this study 21 top-level bodybuilders [users of anabolic steroids (A): n = 14; non-users (N): n = 7] underwent one-dimensional and two-dimensional echocardiography as well as a cycle ergometer test. In both groups blood pressure at rest and during ergometric exercise was within the normal range. In spite of the same amount of time being spent on training, A showed significantly better power results than N. Total heart volume (A = 11.3 +/- 0.9 ml.kg-1; N = 11.9 +/- 0.9 ml.kg-1) and LV muscle mass were almost identical in A and N and correlated significantly with body weight and lean body mass respectively. The body dimension-related diastolic LV diameter was significantly lower in A (0.567 +/- 0.062 mm.kg-1) than in N (0.639 +/- 0.040 mm.kg-1). An increase in the LV posterior wall (p less than 0.01) and septum thickness (ns) resulted in increased LV wall thickness:diameter (p less than 0.01) and LV muscle mass:volume (p less than 0.05) ratios in A (0.458 +/- 0.590; 1.38 +/- 0.25 g.ml-1) in comparison to N (0.356 +/- 0.077; 1.16 +/- 0.17 g.ml-1). The septal:posterior wall thickness ratio was similar for both groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Homologous npdGI Genes in 2,4-Dinitrophenol- and 4-Nitrophenol-Degrading Rhodococcus spp.

Rhodococcus (opacus) erythropolis HL PM-1 grows on 2,4,6-trinitrophenol or 2,4-dinitrophenol (2,4-DNP) as a sole nitrogen source. The NADPH-dependent F₄₂₀ reductase (NDFR; encoded by npdG) and the hydride transferase II (HTII; encoded by npdI) of the strain were previously shown to convert both nitrophenols to their respective hydride Meisenheimer complexes. In the present study, npdG and npdI were amplified from six 2,4-DNP degrading Rhodococcus spp. The genes showed sequence similarities of 86 to 99% to the respective npd genes of strain HL PM-1. Heterologous expression of the npdG and npdI genes showed that they were involved in 2,4-DNP degradation. Sequence analyses of both the NDFRs and the HTIIs revealed conserved domains which may be involved in binding of NADPH or F₄₂₀. Phylogenetic analyses of the NDFRs showed that they represent a new group in the family of F₄₂₀-dependent NADPH reductases. Phylogenetic analyses of the HTIIs revealed that they form an additional group in the family of F₄₂₀-dependent glucose-6-phosphate dehydrogenases and F₄₂₀-dependent N⁵,N¹⁰-methylenetetrahydromethanopterin reductases. Thus, the NDFRs and the HTIIs may each represent a novel group of F₄₂₀-dependent enzymes involved in catabolism.     

Experimental acute hypoxia in healthy subjects: evaluation of systolic and diastolic function of the left ventricle at rest and during exercise using echocardiography

To clarify whether or not systolic and diastolic function of the human left ventricle (LV) were decreased during acute hypoxia, at rest and with exercise, 14 healthy male volunteers [age 25.9 (SD 3.0) years, height 182.9 (SD 7.1) cm, body mass 75.9 (SD 6.9)kg] were examined using M-mode and 2D-mode echocardiography to determine the systolic LV function as well as Doppler-echocardiography for the assessment of diastolic LV function on 2 separate test days. In random order, the subjects breathed either air on 1 day (N) or a gas mixture with reduced oxygen content on the other (H; oxygen fraction in inspired gas 0.14). Measurements on either day were made at rest, several times during incremental cycle exercise in a supine position (6-min increments of 50 W, maximal load 150 W) and in 6th min of recovery. Corresponding measurements during N and H were compared statistically. Arterial O₂ tension (P _aO₂) was normal on N-day. All subjects showed a marked acute hypoxia at rest [P _aO₂, 54.5 (SD 4.6) mmHg], during exercise and recovery on H-day. The latter was associated with tachycardia compared to N-day. All echocardiographic measurements at rest were within the limits of normal values on both test days. Ejection time, end-systolic and end-diastolic left ventricular dimensions as well as the thickness of left posterior wall and of interventricular septum showed no statistically significant influence of H either at rest or during exercise. Stroke volume and cardiac output were always higher on H-day, which could be attributed to a slight reduction in end-systolic volume with unaffected end-diastolic volume as well as to increased heart rates. Among the indices of systolic LV function the fractions of thickening in the left ventricular posterior wall and interventricular septum showed no differences between H and N at rest or during exercise. However, fibre shortening, ejection fraction and mean circumferential fibre shortening were increased on H-day on all occasions. The mitral-valve-Doppler ratio, the index of diastolic LV function, was decreased with H at rest, showed a more pronounced reduction during exercise and was still lower in 6th min of recovery compared to N-day. It was concluded that with acute hypoxia of the severity applied in this study left ventricular systolic function in our healthy subjects showed a pronounced improvement and left ventricular diastolic function was reduced, both at rest and with exercise.     

Reception and learning of electric fields in bees

Honeybees, like other insects, accumulate electric charge in flight, and when their body parts are moved or rubbed together. We report that bees emit constant and modulated electric fields when flying, landing, walking and during the waggle dance. The electric fields emitted by dancing bees consist of low- and high-frequency components. Both components induce passive antennal movements in stationary bees according to Coulomb''s law. Bees learn both the constant and the modulated electric field components in the context of appetitive proboscis extension response conditioning. Using this paradigm, we identify mechanoreceptors in both joints of the antennae as sensors. Other mechanoreceptors on the bee body are potentially involved but are less sensitive. Using laser vibrometry, we show that the electrically charged flagellum is moved by constant and modulated electric fields and more strongly so if sound and electric fields interact. Recordings from axons of the Johnston organ document its sensitivity to electric field stimuli. Our analyses identify electric fields emanating from the surface charge of bees as stimuli for mechanoreceptors, and as biologically relevant stimuli, which may play a role in social communication.     

Bicarbonate infusion and pH clamp moderately reduce hyperventilation during ramp exercise in humans.

To test the hypothesis that the decrease in plasma pH contributes to the hyperventilation observed in humans in response to exercise at high workloads, five healthy male subjects performed a ramp exercise [maximal workload: 352 W (SD 35)] in a control situation and when arterialized plasma pH was maintained at the resting level (pH clamp) by intravenous infusion of sodium bicarbonate [129 mmol (SD 23), beginning at 59% maximal workload (SD 5)]. Bicarbonate infusion did not modify O(2) consumption (Vo(2)) but significantly (P < 0.05) increased arterial Pco(2), plasma bicarbonate concentration, and respiratory exchange ratio (P < 0.05). At the three highest workloads, pulmonary ventilation (Ve) and Ve/Vo(2) were approximately 5-10% lower (P < 0.05) when bicarbonate was infused than in the control situation, and hyperventilation was reduced by 15-30%. These data suggest that the decrease in plasma pH is one of the factors that contribute to the hyperventilation observed at high workloads.     

Arbeiten des botanischen Institutes der k. k. deutschen Universität Prag, 2. Serie,LIV

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