Previous studies have suggested a reduced glucose uptake by the athlete's heart at rest. To examine whether there is a compensatory increase in the myocardial fatty acid utilization, we studied nine ...male endurance-trained athletes (age 26 +/- 2 yr, VO2max 60 +/- 1 ml.kg-1.min-1, mean +/- SEM) and eight sedentary subjects (age 26 +/- 1 yr, VO2max 38 +/- 2 ml.kg-1.min-1) by single photon emission tomography using 123I-heptadecanoic acid (HDA) and mathematical modeling. Magnetic resonance imaging (MRI) and echocardiography were performed for the measurements of cardiac dimensions and left ventricular (LV) mass. No significant differences were found in the myocardial HDA beta-oxidation index (5.2 +/- 2.0 vs 7.4 +/- 1.6 mumol.min-1.100 g-1, P = NS) between endurance-trained and sedentary subjects. Fractional amounts of HDA beta-oxidation, backdiffusion, and esterification were also similar. In MRI study, LV mass was greater in the trained subjects (213 +/- 9 vs 179 +/- 10 g, P < 0.01) and in particular, LV long-axis diameter measured from the mitral valve level to the apex was increased (102 +/- 2 vs 88 +/- 2 mm, P < 0.001, trained vs sedentary subjects). VO2max correlated with LV long-axis diameter (r = 0.77, P < 0.001). In contrast to our hypothesis, myocardial HDA utilization was not enhanced in endurance-trained athletes at rest. Increases in LV mass and especially in LV long-axis diameter were observed in the athletes, indicating LV longitudinal remodeling.
The Particle Telescope (PATE) of FORESAIL-1 mission is described. FORESAIL-1 is a CubeSat mission to polar Low Earth Orbit. Its scientific objectives are to characterize electron precipitation from ...the radiation belts and to observe energetic neutral atoms (ENAs) originating from the Sun during the strongest solar flares. For that purpose, the 3-unit CubeSat carries a particle telescope that measures energetic electrons in the nominal energy range of 80--800 keV in seven energy channels and energetic protons at 0.3--10 MeV in ten channels. In addition, particles penetrating the whole telescope at higher energies will be measured in three channels: one \(>\)800 keV electron channel, two integral proton channels at \(>\)10 MeV energies. The instrument contains two telescopes at right angles to each other, one measuring along the spin axis of the spacecraft and one perpendicular to it. During a spin period (nominally 15 s), the rotating telescope will, thus, deliver angular distributions of protons and electrons, at 11.25-degree clock-angle resolution, which enables one to accurately determine the pitch-angle distribution and separate the trapped and precipitating particles. During the last part of the mission, the rotation axis will be accurately pointed toward the Sun, enabling the measurement of the energetic hydrogen from that direction. Using the geomagnetic field as a filter and comparing the rates observed by the two telescopes, the instrument can observe the solar ENA flux for events similar to the only one so far observed in December 2006. We present the Geant4-simulated energy and angular response functions of the telescope and assess its sensitivity showing that they are adequate to address the scientific objectives of the mission.
To discover whether individual bursal follicles can contain clones of B lymphocytes, we estimated the numbers of lymphoid cell precursors populating single follicles in two types of chicken chimera. ...The first type was produced by establishing parabiotic connections between blood vessels of embryo chorioallantoic membranes. Under these conditions, and most likely during normal development, most follicles are populated by more than one, but less than ten, precursor cells. However, in a second type of chimera, a cyclophosphamide-treated chick reconstituted with normal bursal cells, most follicles in the reconstituted bursa are clonal (their lymphocytes are derived from a single precursor cell). Individual follicles can readily be isolated from bursae of reconstituted birds and should be useful in studies of B cell development.
The systematic position of the freshwater amphipod G. varsoviensis Jażdżewski from northern Poland and Germany, split off recently from G. lacustris Sars in the same area, was assessed by allozyme ...electrophoresis. A distant evolutionary relationship between the two species was indicated, similar to that between them and G. pulex (L.), and to those earlier recorded between marine and freshwater Gammarus spp. (genetic identities I = 0.1-0.2). The neutral terms currently used for subdivisions of the genus, such as the G. pulex group which includes the three species studied, refer to units too ancient to have retained traces of a common ancestry at the allozyme level; adoption of subdivisions based on phylogenetically closer, genetically identifiable relationships is suggested. /// La position systématique de l'amphipode d'eau douce Gammarus varsoviensis Jażdżewski du nord de la Pologne et d'Allemagne, récemment séparé de G. lacustris Sars dans la même région, a été évaluée par électrophorèse allozymatique. Une relation évolutionnaire distante entre les deux espèces a été décelée, semblable à celle entre elles et G. pulex (L.) et à celles précédemment signalées entre les Gammarus sp. marins et d'eau douce (identités génétiques I = 0.1-0.2). Les termes neutres couramment utilisés pour des subdivisions du genre, tels que le groupe pulex, qui inclut les trois espèces étudiées, se réfèrent à des unités trop anciennes pour avoir conservé des traces d'une commune ascendance au niveau allozymatique. Il est suggéré d'adopter des subdivisions fondées sur des relations génétiquement identifiables, phylogénétiquement plus rapprochées.
Interrelation of T(1) and diffusion of water was studied in rat models of acute global and focal cerebral ischemia. Cortical T(1), as quantified with an inversion recovery method, increased by 4-7% ...within a few minutes of global ischemia at 4.7 and 9.4 T, but a significantly smaller change was detected at 1.5 T. The initial T(1) change occurred within seconds of cardiac arrest, much earlier than the extensive diffusion drop after 1-2 min. Thus, the initial increase in T(1) upon acute cerebral ischemia is directly caused by cessation of blood flow. In transient middle cerebral artery occlusion (MCAO), prolonged T(1) relaxation was detected within 10 min, with a subsequent increase during the course of ischemia. Spin density did not change during the first hour, showing that T(1) increase was not caused by net accumulation of water. Interestingly, partial recovery of T(1) upon release of MCAO, occurring independent of long-term tissue outcome, was observed only in concert with diffusion recovery.
A workshop convened to define research needs in toxicology identified several deficiencies in data and methods currently applied in risk assessment. The workshop panel noted that improving the link ...between chemical exposure and toxicological response requires a better understanding of the biological basis for inter-and intra-human variability and susceptibility. This understanding will not be complete unless all life stages are taken into consideration. Because animal studies serve as a foundation for toxicological assessment, proper accounting for cross-species extrapolation is essential. To achieve this, adjustments for dose-rate effects must be improved, which will aid in extrapolating toxicological responses to low doses and from short-term exposures. Success depends on greater use of validated biologically based dose-response models that include pharmacokinetic and pharmacodynamic data. Research in these areas will help define uncertainty factors and reduce reliance on underlying default assumptions. Throughout the workshop the panel recognized that biomedical science and toxicology in particular is on the verge of a revolution because of advances in genomics and proteomics. Data from these high-output technologies are anticipated to greatly improve risk assessment by enabling scientists to better define and model the elements of the relationship between exposure to biological hazards and health risks in populations with differing susceptibilities.
To determine the dose of acetylsalicylic acid (ASA), that inhibits the production of the vasoconstrictive, aggregatory thromboxane A2 while sparing the production of the vasodilatory antiaggregatory ...prostacyclin.
A controlled study comparing the effects of three doses of ASA on the production of thromboxane A2 and prostacyclin.
Seven pregnant hypertensive patients and five non-pregnant healthy women received 0.5, 1.0 and 2.0 mg/kg/day of ASA, each dose for 10-12 days, the treatment periods following each other immediately. Seven normotensive pregnant women served as controls and were given no ASA. Blood and urine samples were taken at baseline and after the treatment periods to determine serum thromboxane B2 and the urinary 2.3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxaneB2, the major stable metabolites of prostacyclin and thromboxane A2, respectively.
The urinary excretion of 11-dehydrothromboxaneB2 was significantly higher in both hypertensive (34.9+/-18.3 pg/micromol creatinine) and normotensive (39.3+/-14.4 pg/micromol creatinine) pregnant women than in non-pregnant women (14.8+/-6.4 pg/micromol creatinine). The urinary excretion of 2.3-dinor-6-ketoprostaglandinF1alpha was also higher in normotensive pregnant women (93.9+/-50.9 pg/micromol creatinine) than in non-pregnant women (18.2+/-11.3 pg/micromol creatinine). The excretion rate of 2.3-dinor-6-ketoprostaglandinF1alpha in hypertensive patients was lower than in normotensive pregnant women (44.7+/-24.2 pg/micromol creatinine). At baseline the urinary 2.3-dinor-6-ketoprostaglandin F1alpha/11-dehydrothromboxaneB2 ratio was almost the same in the hypertensive patients (1.6) and in the non-pregnant women (1.2). The ratio was 2.6 in normotensive pregnant women. In the hypertensive group, already the lowest dose of ASA inhibited urinary 11-dehydrothromboxaneB2 excretion significantly. Because none of the doses of ASA inhibited 2.3-dinor-6-ketoprostaglandinF1alpha production, the 2.3-dinor-6-ketoprostaglandinF1alpha/11-dehydrothromboxaneB2 ratio was shifted in the favor of prostacyclin at all dose levels. In the non-pregnant women, even the highest dose level of ASA failed to affect the ratio.
In the dose range of 0.5-2.0 mg/kg/day, ASA has a favorable effect on the ratio of prostacyclin to thromboxane A2 in hypertensive pregnancies.
We present an experimental study of optical frequency comb generation based on cascaded quadratic nonlinearities inside a continuous-wave-pumped optical parametric oscillator. We demonstrate comb ...states which produce narrow-linewidth intermode beat note signals, and we verify the mode spacing uniformity of the comb at the Hz level. We also show that spectral quality of the comb can be improved by modulating the parametric gain at a frequency that corresponds to the comb mode spacing. We have reached a high average output power of over 4 W in the near-infrared region, at ~2 {\mu}m.
Left ventricular systolic and diastolic function was studied using systolic time intervals and echocardiography in 19 male and 17 female patients with Type 1 (insulin-dependent) diabetes, 24 male and ...15 female patients with Type 2 (non-insulin-dependent) diabetes and 24 male and 24 female control subjects. The subjects for the present study were selected from a population based study in which 117 Type 1 and 510 Type 2 diabetic patients and 649 non-diabetic subjects were originally examined. After exclusions, none of the subjects had any evidence of coronary heart disease, hypertension or other diseases known to affect left ventricular function. There were no consistent differences in systolic time intervals or echocardiographic variables of systolic function between patients with Type 1 diabetes and non-diabetic control subjects; but patients with Type 2 diabetes showed an increased fractional shortening. Female patients with Type 2 diabetes showed an increased left ventricular mass not explicable by hypertension. Isovolumic relaxation period was longer in male (86 +/- 3 ms; mean +/- SEM) and female patients (84 +/- 6 ms) with Type 2 diabetes than in male (76 +/- 3 ms; p less than 0.05) and female (71 +/- 3 ms; p less than 0.05) control subjects. Peak diastolic filling rate was lower in female patients with Type 1 diabetes (12.8 +/- 0.8 cm/s, p less than 0.05) and in male (11.5 +/- 0.8 cm/s; p less than 0.01) and female patients (11.5 +/- 0.6 cm/s; p less than 0.001) with Type 2 diabetes as compared to male (14.4 +/- 0.7 cm/s) and female (14.9 +/- 0.5 cm/s) control subjects.
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