Effects of gonadotropin-releasing hormone agonist administered in microparticles on sperm quality and quantity, and plasma sex steroid levels in northern pike.

Artificial reproduction of northern pike Esox lucius is impeded by the likelihood of obtaining only a small volume of sperm of inconsistent quality. A controlled-release hormone delivery system has the potential to enhance sperm production while avoiding multiple injections The objective of this study was to investigate the effects of mammalian gonadotropin-releasing hormone agonist (mGnRHa) incorporated into poly(lactic-co-glycolic acid) (PLGA) microparticles on milt production, spermatozoon characteristics, and secretion of 17ß-estradiol (E2), 11-keto testosterone (11-KT), and testosterone in northern pike. Fish were divided into four groups and injected with 2 mg/kg BW carp pituitary extract (CPE), 20 µg/kg BW mGnRHa in PLGA microparticles, or 20 µg/kg BW mGnRHa plus 20 mg/kg BW metoclopramide (MET) in PLGA microparticles (PLGA + MET), along with a control group injected with 1 ml/kg 0.9% NaCl. At 48 h postinjection, the volume of milt produced was significantly greater in groups treated with CPE and PLGA + MET than in other groups. At 96 h postinjection, all hormone-treated groups exhibited significantly higher spermatozoon average velocity than recorded in the control group. Spermatozoon motility was significantly increased (P < 0.05) in the CPE and PLGA groups compared to baseline values. All treated groups showed significantly lower levels of 11-KT after the hormone injection compared to baseline values and to controls. Plasma testosterone levels increased in all hormone-treated groups. The use of PLGA microparticles, with or without metoclopramide, is suitable for use as a carrier of hormone treatments to regulate spermiation in mature northern pike.

[Hemostatic effects of oxidized cellulose]. / Hemostatické úcinky oxidované celulosy.

Oxidized cellulose ranks among nontoxic and biocompatible biopolymers. Oxidized regenerated cellulose (ORC) is manufactured from regenerated cellulose derived from wood pulp containing about 50% of cellulose. To obtain purified cellulose, it is necessary to decompose it in a chemical way and subsequently put it together to make "regenerated" cellulose. Thanks to its good hemostatic effects, high biosolubility and biodegradability, antioxidant and wound-healing properties, oxidized cellulose represents a suitable means for the therapy of bleeding conditions in various fields of medicine. In addition, the confirmed bactericidal effects of oxidized cellulose towards a wide spectrum of aerobic and anaerobic pathogens increase the therapeutic potential of this agent for use in clinical practice. At present there is a renewed interest in its wider use in clinical practice and in an improvement of the knowledge of its mechanisms of effects, which are tested in vitro, on animal models as well as in clinical studies. The present paper attempts to summarize the hitherto knowledge of hemostatic properties of oxidized cellulose and also to characterize other possible biological effects.

[Antioxidant activity of tinctures prepared from hawthorn fruits and motherwort herb]. / Antioxidacní aktivita tinktur pripravených z hlohových plodu a nati srdecníku.

The paper aimed to determine and compare the antioxidant activity of two tinctures and selected flavonoids present in the tinctures. The tinctures were prepared from hawthorn fruits and motherwort herb. The group of selected flavonoids included rutin, quercetin, hyperosid, epicatechine, and procyanidin B2. Two methods were employed to determine antioxidant activities: the inhibition of peroxynitrite-induced nitration of tyrosine was measured, and the ability to quench radicals was examined by of the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Both tinctures under study were able to quench radicals and reactive forms of oxygen and nitrogen. The motherwort herb tincture was more effective, but no direct effect of phenolic compounds on the extent of antioxidant activity was demonstrated. The total content of polyphenols in the motherwort herb tincture was higher by 163 %, nevertheless antiperoxynitrite activity was higher just by 19 % (p < 0.05), and the ability to reduce DPPH differed in both tinctures in a minimal manner. Of the individual flavonoids, the substances present in the tinctures in higher concentrations contributed most to antioxidant activity. In the hawthorn fruit tincture it was epicatechine and hyperosid, whereas in the motherwort herb tincture it was rutin.

[Antioxidative activity of some over-the-counter plant extracts]. / Antioxidacní aktivita nekterých volne prodejných rostlinných extraktu.

The recent years again saw increased interest of the public in the use of traditional natural remedies, such as plant extracts, for the treatment and prevention of diseases. This paper evaluates the antioxidative activity and content of phenolic substances of selected plant extracts from medicinal herbs, sold as dietary supplements with therapeutic effects. Using the production of 3-nitrotyrosine as the marker, the effects of extracts on the inhibition of peroxynitrite-induced nitration of tyrosine was examined, and the results were compared with the ability to extinguish the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). A linear correlation (r = 0.929) was found between the ability to extinguish DPPH and to inhibit tyrosine nitration. The found antioxidative activity ranged between values of 0-1702, or 0-1482 micromol of the catechine equivalent/100 ml of the extract. The total content of phenolic substances oscillated within values of 9.4-268.3 mg of the equivalent of gallic acid/100 ml of the extract. The significant linear relationship between antioxidative activities (r>0.9) and the total content of phenolic substances shows that phenolic substances are the principal group responsible for the antioxidative activity of the extracts tested.