There has been increasing evidence in recent years for the hypothesis of bones as endocrine organs. Osteocalcin, long considered just a marker of new bone formation, is now seen as the first hormone produced by bones, and seems to be associated with regulating glucose metabolism and reproduction. The aim of this work was to monitor changes of osteocalcin in reaction to hypoglycemia, and determine if there are differences in such reactions between the sexes. The study included 61 healthy probands with physiological calciophosphate metabolism (30 men and 31 women). We applied to each of them an insulin tolerance test, and then monitored levels of undercarboxylated osteocalcin and reactions to hypoglycemia at regular time intervals. We found differences in the reaction to hypoglycemia between the sexes. In men there was a significant decline in undercarboxylated osteocalcin between the 30 and 40 min (p<0.0015), which reflects a reaction to a glycemic decline between 25-30 min, followed by reversal. Low undercarboxylated osteocalcin in men lasted up to 90 min, after which they returned to levels before the test. In women we did not find any significant changes in undercarboxylated osteocalcin levels. Changes in undercarboxylated osteocalcin induced by hypoglycemia indicate a relationship between bones and glucose metabolism. There was an interesting difference between the sexes. However, a definitive conclusion about the role of osteocalcin in human metabolism will require numerous future studies., Michaela Dušková, Lucie Kolátorová, Hana Jandíková, Hana Pospíšilová, Luboslav Stárka., and Obsahuje bibliografii
Many areas of biology employ standard model organisms on which a majority of research effort is concentrated. However, there is invariably a danger associated with the use of too few or atypical models for studies of particular taxonomic groups, guilds or biological phenomena. Using aphidophagous ladybirds, I show that in this group, in the last ten years, 69% of research has been concentrated on just five species, all generalist ecotypes. Much research is now concentrated on invasive species, originally biocontrol agents, and over half the aphidophagous ladybird work on intraguild interactions is centred on two of the five predominant species, Coccinella septempunctata and Harmonia axyridis. Using examples from differing areas of research, I show that studies of more unusual, non-commercial specialists can enhance our understanding of the commonly studied groups. I suggest further areas where a similar approach may lead to equally illuminating results.
Altogether 445 bats, representing nine species, caught during swarming in the Lodowa Cave in Mount Ciemniak, Western Tatra Mountains, southern Poland, were examined for ectoparasitic mites. In total, 259 spinturnicid (Spinturnix mystacina, S. andegavinus, S. kolenatii, S. plecotinus and S. myoti) and 95 argasid (Carios vespertilionis) mites were collected from seven bat species, Myotis myotis, M. mystacinus, M. brandtii, M. daubentonii, Eptesicus nilssonii, Plecotus auritus, and Vespertilio murinus. There were sex-based differences in the prevalence of mites in some hosts but no differences in their mean intensity and there was no observed relationship between the number of mites and the condition of the bats. The prevalence of mites differed significantly between years in E. nilssonii. The results suggested a very low mite load on swarming bats that had no impact on the body condition of bats.
Invazivní metody léčby chronické formy ischemické choroby srdeční byly po dlouhou dobu považovány za kauzální terapii, která bezpochyby snižuje morbiditu a mortalitu nemocných. Na druhé straně životní styl a farmakologická terapie byla nahlížena jako spíše doplňující, ale nikoliv rozhodující léčba. V posledních letech je možno vidět změnu v pohledu na ischemickou chorobu srdeční. Je to mnohem difuznější proces v koronráním řečišti a není to tedy jen otázka kritických stenóz, ale stejně nemocného ohrožují i další úseky věnčitých tepen, kde se hovoří o vulnerabilních placích. Překvapením pro experty byly závěry řady studií potvrzujících neschopnost invazivch metod prodloužit život nemocným s chronickou formou ICHS. Na druhé straně přibývají důkazy o významném vlivu úpravy životního stylu a rozrůstajících se možnostech farmakolgoické terapie s pozitivním vlivem na morbiditu a mortalitu. Článek prezentuje současné názory na tyto otázky, které jsou nyní živě diskutovány., Invasive methods for treatment of coronary artery disease in chronic form were, for a long time, believed to be causal treatment that definitely diminish patient morbidity and mortality. By contrast, lifestyle and pharmacological therapy were seen as valuable but not lifesaving. In the last few years a change can be seen in the view on coronary artery disease. It is a much more diffusive and complicated process in the coronary tree. It is not merely a question of the critical stenotic areas; the new idea of vulnerable plaque, which presents the same danger of complication as critically stenotic areas, is also important. A great surprise for experts was the result of various studies confirming the inability of invasive procedures to prolong life in patients with chronic coronary disease. On the other hand, there has been more evidence that lifestyle changes and expanding pharmacological possibilities can have a significant positive effect on morbidity and mortality. This article aims to present the problem as it is currently being discussed., and Kotík L.
The feeding behaviour of specialist butterflies may be affected by the mechanical and chemical characteristics of the tissues of their host-plants. Larvae of the butterfly, Battus polydamas archidamas feed only on Aristolochia chilensis, which contains aristolochic acids. We studied the oviposition pattern of adults and the foraging of larvae of B. polydamas archidamas over time in relation to variations in hardness of the substrate and concentration of aristolochic acids in different plant tissues. We further tested the effect of two artificial diets containing different concentrations of aristolochic acids on larval performance. B. polydamas archidamas oviposited mostly on young leaves and the larvae fed on this tissue until the second instar. Third instar larvae fed also on mature leaves and fourth and higher instars fed also on stems. Young leaves are softer and contain higher concentrations of aristolochic acids than mature leaves, and stems are both harder and contain a high concentration of aristolochic acids. Larvae reared on artificial diets containing a high concentration of aristolochic acids suffered less mortality and were heavier than those reared on a diet with a lower concentration of aristolochic acids, which suggests they are phagostimulatory. A strategy of host use regulated by aristolochic acid content and tissue hardness is discussed.
In this paper we establish the distribution of prime numbers in a given arithmetic progression $p \equiv l \hspace{4.44443pt}(\@mod \; k)$ for which $ap + b$ is squarefree.
We consider positional numeration system with negative base −β, as introduced by Ito and Sadahiro. In particular, we focus on arithmetical properties of such systems when β is a quadratic Pisot number. We study a class of roots β>1 of polynomials x2−mx−n, m≥n≥1, and show that in this case the set Fin(−β) of finite (−β)-expansions is closed under addition, although it is not closed under subtraction. A particular example is β=τ=12(1+5–√), the golden ratio. For such β, we determine the exact bound on the number of fractional digits appearing in arithmetical operations. We also show that the set of (−τ)-integers coincides on the positive half-line with the set of (τ2)-integers.