Exercise-Induced Changes in Iron Status and Hepcidin Response in Female Runners

Background and Aims

Exercise-induced iron deficiency is a common finding in endurance athletes. It has been suggested recently that hepcidin may be an important mediator in this process.

Objective

To determine hepcidin levels and markers of iron status during long-term exercise training in female runners with depleted and normal iron stores.

Methods

Fourteen runners were divided into two groups according to iron status. Blood samples were taken during a period of eight weeks at baseline, after training and after ten days’ recovery phase.

Results

Of 14 runners, 7 were iron deficient at baseline and 10 after training. Hepcidin was lower at recovery compared with baseline (p<0.05). The mean cell haemoglobin content, haemoglobin content per reticulocyte and total iron binding capacity all decreased, whereas soluble transferrin receptor and hypochromic red cells increased after training and recovery (p<0.05 for all).

Conclusion

The prevalence of depleted iron stores was 71% at the end of the training phase. Hepcidin and iron stores decreased during long-term running training and did not recover after ten days, regardless of baseline iron status.     

The occurrence of Ambrosia pollen in Rzeszów,Kraków and Poznań, Poland: investigation of trends and possible transport of Ambrosia pollen from Ukraine

Previous studies have shown that ragweed pollen arrives in Poland from sources in the south, in Slovakia, the Czech Republic, Hungary and Austria. It is likely that ragweed pollen also arrives from sources in the southeast (e.g. Ukraine). This hypothesis was investigated using 13 years of pollen data and back-trajectory analysis. Ambrosia pollen data were collected at three sites in Poland, Rzeszów, Kraków and Poznań. The amount of ragweed pollen recorded at Rzeszów was significantly higher than in Poznań and Kraków. This can be related to either a higher abundance of local populations of Ambrosia in south-east Poland or the proximity of Rzeszów to foreign sources of ragweed pollen. The combined results of pollen measurements and air mass trajectory calculations identified plumes of Ambrosia pollen that were recorded at Rzeszów, Kraków and Poznań on 4 and 5 September 1999 and 3 September 2002. These plumes arrived at the pollen-monitoring sites from an easterly direction, indicating sources of Ambrosia pollen in eastern Poland or Ukraine. This identifies Ukraine as a possible new source of ragweed pollen for Poland and therefore an important source area of Ambrosia pollen on the European Continent.     

Specific impact of cardiovascular risk factors on coronary microcirculation in patients with subclinical hypothyroidism

BackgroundAlthough thyroid hormones have significant effect on cardiovascular system, the impact of subtle thyroid dysfunction such as subclinical hypothyroidism (SCH) remains to be determined. We investigated coronary flow reserve (CFR) in patients with subclinical hypothyroidism.MethodsThirty two subjects with SCH and eighteen control subjects with normal serum thyroid hormones and thyroid-stimulating hormone (TSH) levels were included in the study. TSH, free thyroxine, free triiodothyronine, glucose, insulin, HbA1c, cholesterol, triglyceride and plasma levels of C-reactive protein were measured. Coronary diastolic peak flow velocities in left anterior descending coronary artery were measured at baseline and after adenosine infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocity.ResultsCFR values were not significantly different between the two groups (SCH 2.76±0.35 vs controls 2.76±0.42). There was a significant correlation of CFR with waist to hip ratio, hypertension, smoking habits, markers of glucose status (glucose level, HbA1c, insulin level, HOMA IR), cholesterol, LDL-cholesterol and triglyceride levels in SCH group, whereas only cholesterol level showed significant correlation with CFR in controls. There was no correlation between CFR and thyroid hormones.ConclusionsWe concluded that there is a different impact of cardiovascular risk factors on CFR in SCH patients compared to healthy control and that these two groups behave differently in the same circumstances under the same risk factors. The basis for this difference could be that the altered thyroid axis "set point" changes the sensitivity of the microvasculature in patients with SCH to known risk factors.     

Use of the β‐function to estimate the skewness of species responses

Abstract. Response of a species to an environmental variable may be modeled and predicted using a wide spectrum of different functions. Contrary to other functions (Gaussian, polynomial etc), all parameters of the β‐function are interpretable in ecological terms. However, computational difficulties in the determination of the β‐function parameters initiated controversial debates on the applicability and usefulness of this function in vegetation modelling and gradient analysis. We propose a simple algorithm for fitting the β‐function to observed data. Analytic properties of the algorithm (its ability to recover the known species responses along gradients) are tested using a series of simulated data. In most cases the algorithm correctly estimated parameters of the simulated responses.     

Age, growth and mortality of red bandfish, Cepola macrophthalma (L.), in the eastern Adriatic Sea (Croatian coast)

Age, growth and mortality were analysed for red bandfish, Cepola macrophthalma, collected in the eastern Adriatic from May 2002 to June 2003. The oldest male was estimated to be age 4, the oldest female age 3. Parameters of the von Bertalanffy growth equation are: L_∞ = 55.0 cm (SE = 0.1), K = 0.445 (SE = 0.074) and t₀ = ?0.1 (SE = 0.001) for males, and L_∞ = 48.9 cm (SE = 0.167), K = 0.395 (SE = 0.062) and t₀ = ?0.009 (SE = 0.02) for females. The overall sex ratio was 1.42 : 1 in favour of males. Total mortality, corresponding to the slope of the descending limb of the catch curve, was Z = 1.20 per year for females and Z = 1.23 per year for males. Exploitation ratios were E = 0.479 for females and E = 0.433 for males.     

Naturally safe: Cellular noise for document security

Modern document protection relies on the simultaneous combination of many optical features with micron and submicron structures, whose complexity is the main obstacle for unauthorized copying. In that sense, documents are best protected by the diffractive optical elements generated lithographically and mass‐produced by embossing. The problem is that the resulting security elements are identical, facilitating mass‐production of both original and counterfeited documents. Here, we prove that each butterfly wing‐scale is structurally and optically unique and can be used as an inimitable optical memory tag and applied for document security. Wing‐scales, exhibiting angular variability of their color, were laser‐cut and bleached to imprint cryptographic information of an authorized issuer. The resulting optical memory tag is extremely durable, as verified by several century‐old insect specimens still retaining their coloration. The described technique is simple, amenable to mass‐production, low cost and easy to integrate within the existing security infrastructure.     

The contribution of dichotomous keys to the quality of biological-botanical knowledge of eighth grade students

The aim of the research is to examine the contribution of applying author-generated dichotomous keys (digital key - DDK and print key - DPK) to the quality and durability of the knowledge of eighth grade students about the Systematic and classifications of plants (Bryophyta, Pteridophyta, Gymnosperms and Angiosperms), as compared to traditional teaching. The study included 180 eighth grade students from Montenegro (12–13 years old) divided into three groups: E₁ (where content was learned through DPK), E₂ (where content was learned through DDK) and K (where content was learned through the verbal-textual method). Dichotomous keys contributed to increasing the quality and durability of the knowledge acquired in comparison to traditional teaching at the cognitive levels of analysis, evaluation and synthesis. DDK contributed to the higher quality and durability of student knowledge in comparison to DPK at the cognitive levels of evaluation and synthesis.     

Role of LARP6 and Nonmuscle Myosin in Partitioning of Collagen mRNAs to the ER Membrane

Type I collagen is extracellular matrix protein composed of two α1(I) and one α2(I) polypeptides that fold into triple helix. Collagen polypeptides are translated in coordination to synchronize the rate of triple helix folding to the rate of posttranslational modifications of individual polypeptides. This is especially important in conditions of high collagen production, like fibrosis. It has been assumed that collagen mRNAs are targeted to the membrane of the endoplasmic reticulum (ER) after translation of the signal peptide and by signal peptide recognition particle (SRP). Here we show that collagen mRNAs associate with the ER membrane even when translation is inhibited. Knock down of LARP6, an RNA binding protein which binds 5′ stem-loop of collagen mRNAs, releases a small amount of collagen mRNAs from the membrane. Depolimerization of nonmuscle myosin filaments has a similar, but stronger effect. In the absence of LARP6 or nonmuscle myosin filaments collagen polypeptides become hypermodified, are poorly secreted and accumulate in the cytosol. This indicates lack of coordination of their synthesis and retro-translocation due to hypermodifications and misfolding. Depolimerization of nonmuscle myosin does not alter the secretory pathway through ER and Golgi, suggesting that the role of nonmuscle myosin is primarily to partition collagen mRNAs to the ER membrane. We postulate that collagen mRNAs directly partition to the ER membrane prior to synthesis of the signal peptide and that LARP6 and nonmuscle myosin filaments mediate this process. This allows coordinated initiation of translation on the membrane bound collagen α1(I) and α2(I) mRNAs, a necessary step for proper synthesis of type I collagen.