Apoptotic index within cumulus cells is a questionable marker of meiotic competence of bovine oocytes matured in vitro

Information gained from most human studies indicate a negative correlation between the apoptotic index (AI) in cumulus cells (CC) and the quality of the corresponding oocytes. However, results obtained in other species are not so consistent. The rate of apoptosis-free COCs (cumulus oocytes complexes) subjected to IVM (in vitro maturation) also varies among studies. The aim of the present study was to investigate whether the AI in cumulus cells of post-IVM COCs is related to the morphology of pre-IVM COCs and to meiotic competence of bovine oocytes. COCs of known morphology (four grade scale) obtained from individual follicles were matured in a well-in-drop system. After IVM, the external layers of CC of each COC were analyzed by TUNEL. In order to determine the meiotic stage, oocytes were stained with DAPI. It was found that 25.6% of bovine COCs contained apoptosis-free cumulus cells. Moreover, the majority of COCs with apoptotic cells were characterized by apoptotic index lower than 15%. The level of apoptosis in CC was related neither to COC morphology nor to the oocyte meiotic stage. It is suggested that the extent of apoptosis in cumulus cells is not a reliable quality marker of the corresponding oocyte after IVM.     

Most organs of sugar-beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.) plants at the vegetative and reproductive stages of development are polysomatic

Polysomaty was studied using flow cytometry in different organs of diploid, triploid and tetraploid sugar-beet (Beta vulgaris L.) plants, in the first (at harvest) and the second (at the height of the blooming period) year of development. Of the organs/parts of organs of the vegetative plant that developed during the first year, only the leaf lamina did not contain endopolyploid cells; in all others, one to three endocycles had occurred. The second-year seed-crop plant was also highly polysomatic; even in reproductive organs such as the flower and pericarp the endopolyploid cells were present (up to 8C and 32C, respectively). At this stage of development no endocycles occurred in the leaf lamina, flower bract, and inflorescence bract. The parts of the plant with no endopolyploid cells are recommended for ploidy estimation, and as a material suitable for micropropagation and genetic manipulations. Endoreduplication, up to 32C (64Cx), was organ-specific and correlated negatively with plant ploidy. The highest mean C-value, over 7, was in the diploid, in the basal part of the oldest leaf petiole in the first-year plant, and in the storage parenchyma of the root in the second-year seed-crop plant. The results confirm that higher endopolyploidy occurs in plants with a smaller 2C DNA amount than in those with a larger one. The significance of endopolyploidization in development of sugar-beet plant organs is discussed.     

Bidirectional regulation of renal cortical Na+,K+-ATPase by protein kinase C

We examined the role of protein kinase C (PKC) in the regulation of Na+,K+- ATPase activity in the renal cortex. Male Wistar rats were anaesthetized and the investigated reagents were infused into the abdominal aorta proximally to the renal arteries. A PKC-activating phorbol ester, phorbol 12,13-dibutyrate (PDBu), had a dose-dependent effect on cortical Na+,K+-ATPase activity. Low dose of PDBu (10(-11) mol/kg per min) increased cortical Na+,K+-ATPase activity by 34.2%, whereas high doses (10(-9) and 10(-8) mol/kg per min) reduced this activity by 22.7% and 35.0%, respectively. PDBu administration caused changes in Na+,K+-ATPase Vmax without affecting K(0.5) for Na+, K+ and ATP as well as Ki for ouabain. The effects of PDBu were abolished by PKC inhibitors, staurosporine, GF109203X, and G? 6976. The inhibitory effect of PDBu was reversed by pretreatment with inhibitors of cytochrome P450-dependent arachidonate metabolism, ethoxyresorufin and 17-octadecynoic acid, inhibitors of phosphatidylinositol 3-kinase (PI3K), wortmannin and LY294002, and by actin depolymerizing agents, cytochalasin D and latrunculin B. These results suggest that PKC may either stimulate or inhibit renal cortical Na+,K+-ATPase. The inhibitory effect is mediated by cytochrome P450-dependent arachidonate metabolites and PI3K, and is caused by redistribution of the sodium pump from the plasma membrane to the inactive intracellular pool.     

Novel 1-O-indole-3-acetyl-β-d-glucose-dependent acyltransferase transferring indoleacetyl moiety to some mono- di- and oligosaccharides

1-O-(indole-3-acetyl)-β-d-glucose: sugar indoleacetyl transferase (1-O-IAGlc-SugAc) is a novel enzyme catalyzing the transfer of the indoleacetyl (IA) moiety from 1-O-(indole-3-acetyl)-β-d-glucose to several saccharides to form ester-linked IAA conjugates. 1-O-IAGlc-SugAc was purified from liquid endosperm of Zea mays by fractionation with ammonium sulphate, anion-exchange, Blue Sepharose chromatography, affinity chromatography on Concanavalin A-Sepharose, adsorption on hydroxylapatite and preparative PAGE. The obtained enzyme preparation indicates only one band of R _f 0.67 on 8% non-denaturing PAGE consisting of two polypeptides of 42 and 17 kDa in SDS/PAGE. Highly purified 1-O-IAGlc-SugAc shows maximum transferase activity with monosaccharides (mannose, glucose, and galactose), lower activity with disaccharides (melibiose, gentobiose) and trisaccharide (raffinose) and minimal enzymatic activity with oligosaccharides from the raffinose family as well. The novel acyltransferase exhibits, besides its primary indoleacetylation of sugar, minor hydrolytic and disproportionation activities producing free IAA and supposedly 1,2-di-O-(indole-3-acetyl)-β-glucose, respectively. Presumably, 1-O-IAGlc-SugAc, like 1-O-indole-3-acetyl-β-d-glucose-dependent myo-inositol acyltransferase (1-O-IAGlc-InsAc), is another member of the serine carboxypeptidase-like (SCPL) acyltransferase family.     

Effects of Combined Dietary Chromium(III) Propionate Complex and Thiamine Supplementation on Insulin Sensitivity, Blood Biochemical Indices, and Mineral Levels in High-Fructose-Fed Rats

Insulin resistance is the first step in glucose intolerance and the development of type 2 diabetes mellitus, thus effective prevention strategies should also include dietary interventions to enhance insulin sensitivity. Nutrients, such as microelement chromium(III) and thiamine, play regulatory roles in carbohydrate metabolism. The objective of this study was to evaluate the insulin-sensitizing potential of the combined supplementary chromium(III) propionate complex (CrProp) and thiamine in insulin resistance animal model (rats fed a high-fructose diet). The experiment was carried out on 40 nine-week-old male Wistar rats divided into five groups (eight animals each). Animals were fed ad libitum: the control diet (AIN-93?M) and high-fructose diets with and without a combination of two levels of CrProp (0.1 and 1?mg Cr/kg body mass/day) and two levels of thiamine (0.5 and 10?mg/kg body mass/day) for 8?weeks. At the end of the experiment rats were sacrificed to collect blood and internal organs for analyses of blood biochemical and hematologic indices as well as tissular microelement levels that were measured using appropriate methods. It was found that both supplementary CrProp and thiamine (given alone) have significant insulin-sensitizing and moderate blood-lipid-lowering properties, while the combined supplementation with these agents does not give synergistic effects in insulin-resistant rats. CrProp given separately increased kidney Cu and Cr levels, while thiamine alone increased hepatic Cu contents and decreased renal Zn and Cu contents.     

The influence of lactose intolerance and other gastro-intestinal tract disorders on L-thyroxine absorption

The preferred treatment for hypothyroidism is oral levothyroxine (LT4) ingestion, in doses that ensure a sustained state of hormonal balance. Many different factors may significantly influence the absorption of LT4, including: interval between the ingestion of the drug and the last meal, eating habits, and different functional and organic pathologies of the gastro-intestinal tract. The main purpose of this paper is to review and systematise the available literature on the subject of the influence of different malabsorption syndromes on the effectiveness of LT4 preparations. The need to use high LT4 doses in the substitutional treatment of hypothyroidism is often the very first sign of one of the pathologies that are connected with malabsorption syndrome, which might have been asymptomatic and undiagnosed previously. Patients who require more than 2 μg/kg body weight of LT4 per day, with constantly increased thyrotropin level, should be diagnosed with the suspicion of pseudomalabsorption or real absorption disorder. An LT4 absorption test, using high doses of LT4, may be useful in the diagnosis of pseudomalabsorption. After excluding non-compliance, the differential diagnosis should include such disorders as lactose intolerance, coeliac disease, atrophic gastritis, Helicobacter pylori infection, bowel resection, inflammatory bowel disease, and parasite infection. Where there is a diagnosis of lactose intolerance, both a low lactose diet and a lactose-free LT4 preparation should be administered to restore euthyroidism or make it possible to decrease the dose of the LT4 preparation. In coeliac disease, a gluten-free diet usually allows a normalisation of the need for LT4, as do eradication of the H. pylori infection or parasite colonisation. In cases of atrophic gastritis or inflammatory bowel disease, treating the underlying diseases and regaining the state of remission may improve the absorption of LT4. In patients after gastro-intestinal tract surgery, a dose of LT4 higher than that typically used is needed to restore euthyroidism.     

Production and Identification of Biologically Active Peptides Derived from By-product of Hen Egg-Yolk Phospholipid Extraction

International Journal of Peptide Research and Therapeutics - Biologically active peptides derived from food proteins have been increasingly popular due to their therapeutic properties. This paper...     

Immunohistochemical evaluation of cell proliferation and apoptosis markers in ovarian surface epithelial cells of cladribine-treated rats

Cladribine has been used in the treatment of hairy cell leukemia for about 30 years. In addition, the number of indications for the application of 2-CdA is constantly increasing. The treatment with cladribine, of younger persons and even children, appears to be a major factor stimulating the more exact recognition of its activities. However, till now, little has been known about the impact of cladribine on the reproductive system. The aim of the study was to evaluate the immunohistochemical expression of cell proliferation and apoptosis markers in ovarian surface epithelial (OSE) cells. In our study, ten rats were placed into two equal groups. The study group received daily subcutaneous injections of cladribine in a dose of 0.10 mg/kg of weight/day for one cycle lasting 7 days. The control group received only saline injections. The rats were sacrificed 24 h after the last injection, and their ovaries were extracted. The sections were immunohistochemically stained with cell proliferation marker Ki-67 and the apoptosis marker caspase 3. The expressions of the markers were evaluated using a light microscope. An analysis was made using an image analysis system and the CellAD software. The results were then statistically explored by way of the Mann–Whitney U test. The proliferative index (Ki-67) of ovarian surface epithelial cells was significantly lower in the study group than in the control group (p?<?0.05). These results suggest that cladribine treatment has a potential to inhibit the OSE cell proliferation in rats. The apoptosis marker demonstrated a significant increase after the cladribine treatment. These suggest that cladribine induces apoptosis in OSE cells.