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Content available The role of boron in animal health
Boron is a mineral used for various purposes in glass, ceramics, automotive and paint industries. Recently, boron has been confirmed to be an essential element for plants, animals and humans, although the knowledge of its biological effects is rather scanty. Boron is a dynamic trace element, and inorganic borates are transformed into boric acids and absorbed from mucosal surfaces, even when they are in low levels of physiological pH. It has been determined that boron affects many enzymes, bone development, mineralization, Ca, P, Mg and energy metabolism. Boron mineral compounds can be effective in optimizing the performance of an organism, treatment of bone structure disorders, reduction of cholesterol and triglyceride levels. Beside the effects it produces specifically on fat and lipid metabolisms, boron can influence the activity of vitamin D and affect some disorders connected with its deficiency. Although several studies on effects of boron on some mechanisms have been conducted over the last ten years, the available information remains insufficient.
The calcium-binding protein S100B is produced primarily by astrocytes and exerts concentration-dependent paracrine and autocrine effects on neurons and glia. The numerous findings of a correlation between S100B and traumatic brain injury (TBI) have resulted in the employment of this protein as a clinical biomarker for such injury. Our present aim was to determine whether cycling with (V) or without (NV) vibration alters serum concentrations of S100B. Twelve healthy, male non-smokers (age: 25.3±1.6 yrs, body mass: 74.2±5.9 kg, body height: 181.0±3.7 cm, VO2peak: 56.9±5.1 ml·min-1·kg-1 (means ± SD)) completed in random order two separate trials to exhaustion on a vibrating bicycle (amplitude 4 mm and frequency 20 Hz) connected to an ergometer. The initial workload of 100 W was elevated by 50 W every 5 min and the mean maximal period of exercise was 25:27±1:30 min. The S100B in venous blood taken at rest, immediately after the test, and 30, 60 and 240 min post-exercise exhibited no significant differences (p>0.05), suggesting that cycling with and without vibration does not influence this parameter.
The rate of superovulation and embryo production in 120 beef and 177 Black-WhitexHolstein-Fresian (BWxHF) cows treated with a new generation of FSH preparations – Stimufol (Rhone Merieux) and Ovagen (ICP) were compared with those treated with frequently used FSH-P. BWxHF cows treated with Stimufol and Ovagen revealed a significantly higher (P<0.05) number of embryos suitable for a transfer than those treated with FSH-P. In contrast to FSH-P., Stimufol failed to increase the rate of embryo production in Aberdeen-Angus and Limousine cows.
The goal of this study was the assessment of the influence on both insulin and growth hormone levels in lambs blood of blood meal and Wroclaw product - dry brown livex (modified by whey). Experiments were carried out on 30 young Polish "wielkopolska" lowland - sheep - wool type, aged 3-4 months. Livex and blood meal constituted 2% of forage. Blood samples for radioimmunologic examinations (GH and insulin level determination) were taken 1 hour before feeding, directly before feeding and 1.0, 1.5, 2.0, 3.0, 5.0, 6.0 and 8.0 hours afterwards. During the experiment higher levels of insulin and GH were observed in animals fed with livex and forage mixture than in animals fed with blood meal and forage mixture. Livex caused a bigger body mass increase (mean increase 27.3%) in comparison with animals fed with control forage. Although neither livex nor blood meal are hormone preparations, changes in insulin and growth hormone levels were observed.
Body condition can influence bovine fertility, but the morphological, biochemical and endocrine mechanisms of this influence are not fully understood. The aim of the study was to examine the interrelationships between cow body condition, morphological and endocrine state of the ovary, and blood metabolic indexes. Czech Fleckvieh dairy cows at the follicular phase of the ovarian cycle and with a tendency towards emaciation (body condition scoreCS2) and cows with an average body condition score (BCS3) were compared. Plasma concentrations of aspartate aminotransferase (AST), non-esterified fatty acids (NEFAs), Ca2+, inorganic phosphorus (Pi ), Mg2+, Fe2+, Cu2+, Zn2+ (determined using photometrically), leptin and insulin (ELISA), ovarian area, number of visible ovarian follicles, diameter of primary and secondary ovarian follicles and corpora albicantia (macro- and micrometric analysis of ovarian histological sections), as well as the release of progesterone, testosterone, oestradiol and insulin-like growth factor I (IGF-I) by isolated ovarian granulosa cells (RIA) were analysed. No significant differences between BCS2 and BCS3 cows in blood metabolic and endocrine indexes (except for decreased Zn2+ in BCS3 cows) were found. The ovaries of BCS2 cows, however, showed a lower ovarian area, diameter of both primary and secondary follicles and corpora albicantia, but not the number of visible secondary follicles as compared with BCS3 cows. No differences between the release of progesterone, testosterone and IGF-I by ovarian granulosa cells isolated from BCS2 or BCS3 cows were found, but the granulosa cells of BCS2 animals released more oestradiol than those of BCS3 cows. These results indicate that a slight reduction in BCS (tendency towards emaciation) does not substantially affect ovarian secretory activity or metabolic blood indexes. On the other hand, a tendency towards emaciation is associated with reduced ovarian follicle growth (but not their number) and increased secretion of oestradiol. These observations suggest that a tendency towards emaciation can suppress bovine fertility via alterations in ovarian folliculogenesis and oestrogen release.
Content available remote Malatonin in humans
Melatonin, the hormone of the pineal gland, received a great deal of attention in the last decade because of its availability as over-the-counter drug or food supplement in some countries and suggested role in many vital physiological processes. Melatonin secretion is not restricted to mammals but is also produced in nonmammalian vertebrates, in some invertebrates, and in many plants, with the same molecular structure. The synthesis of melatonin is strictly controlled by lighting conditions and shows a clear circadian rhythm with low values during the daytime and significant increase at night. In this survey the basic data on melatonin significance in human physiology and in pathological processes as well as its possible thrapeutic significance are reviewed and discussed.
On the basis of flexibility of the carbon skeleton of a juvenoid molecule, an analysis of its steric properties required to induce a biological effect in insects Dysdercus cittgulatus and Tenebrio molitor, is presented. Steric analyses of "branched" juvenoids and some derivatives of farnesoic acid differing in position of the double bonds, are also described.
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