The role of estrogens in the regulation of lactate dehydrogenase activity and its submolecular organization in rat anterior pituitary

Estrogens increase LDH activity and decrease H/M subunit ratio in rat anterior pituitary in both the experimental circumstances and the physiological conditions. The cellular messengers mediating estrogenic effect are structure- and stereospecific. The activity increasing and subunit ratio decreasing potency of the three tested estrogens was of following decreasing order: 17 beta-estradiol, estrone, and estriol. 17 alpha-estradiol did not affect activity parameters and submolecular organisation of the enzyme. The estrogen induced activity increase is consequence of the enhanced de novo enzyme protein synthesis which could be inhibited by Actinomycin-D. The lack of adrenocorticoids did not involve the alteration of LDH activity and H/M ratio in female rat anterior pituitary. Accordingly, these steroids do not mediate estrogenic action. 17 beta-estradiol had a substantial increasing effect on LDH activity in the subrenal implanted pituitary homografts and decreased H/M subunit ratio. Pituitary LDH activity in androgenized female rats decreased only after the removal of the polycystic ovaries. The two latter observations suggest that hypothalamic hormones are not involved in the regulation of pituitary LDH activity and its submolecular organization. De novo synthesis of LDH enzyme protein and the regulation its submolecular organization is induced by the direct action on anterior pituitary cells of the estrogens.     

Elemental Concentration in Mealworm Beetle (Tenebrio molitor L.) During Metamorphosis

Mealworm beetles have been used in numerous experiments as bioindicators. The aim of our experiment was to study the elemental composition in three larvae, pupae and first and second generation adult stages during their life cycle. We selected 180 larvae from a genetically similar population and put them in three groups, in two boxes (60 larvae in each box). Larvae were fed with mashed potato made of the same quality and quantity of potato powder. Then, we selected 10 individuals from each stage to the elemental analysis, using the ICP-OES method. The following elements were analysed in the studied stages: Ca, Cu, Fe, K, Mg, Mn, Na, P, S, Sr and Zn. The results of principal component analysis demonstrated that based on elemental composition, different stages were separated with each other, but in the cases of the three larvae stages, high overlap was found. The results of the GLM ANOVA showed significant differences between the different stages of metamorphosis-based elemental composition. Our results show that the calcium and magnesium were found in a relatively high concentration, while the iron and zinc may be essential elements during the metamorphosis. Our results also show that in insect, the concentration of sodium was higher than in the pupa which may cause by hemolymph. We also demonstrated that the metamorphosis has an effect on the concentration of elements. Our study shows that in the different stages of insects, there are significant changes in the elemental composition of different stages of insects during their metamorphosis.     

Binding of trastuzumab to ErbB2 is inhibited by a high pericellular density of hyaluronan

Although trastuzumab is an efficient drug, primary and acquired resistance is a challenging problem. The authors have previously shown in mouse xenograft experiments that masking ErbB2 by hyaluronan leads to diminished binding of the antibody and consequent resistance. In the current work, they correlated trastuzumab binding with the pericellular density of hyaluronan in ErbB2-overexpressing human breast cancer samples. A method for quantifying the relative binding of trastuzumab was developed involving constant and low-frequency background subtraction, segmenting the image to membrane and background pixels followed by evaluation of trastuzumab fluorescence, normalized with the expression level of ErbB2, only in the membrane. The normalized binding of trastuzumab showed a negative correlation with the pericellular density of hyaluronan (r = -0.52) with the effect being the most pronounced in the extreme cases (i.e., low and high hyaluronan densities predicted strong and weak binding of trastuzumab, respectively). Removal of hyaluronan by hyaluronidase digestion unmasked the trastuzumab binding epitope of ErbB2 demonstrated by a significantly increased normalized binding of the antibody. The results show that the accumulation of pericellular hyaluronan plays a crucial role in masking ErbB2.     

Morphological and immunophenotypical heterogeneity in breast cancers of young and elderly women

There is a reasonable heterogeneity in the morphological appearance and the immunohistochemical properties of distinct breast tumors. Furthermore, it is also known that cancer arising in young women have different prognosis than the ones developing in the elderly. We analyzed breast tumors of 41 young (<35 years) and 33 older women (>65 years) regarding histopathological properties and immunohistochemical reactions for ER, PgR, HER2 and Ki-67, as well as HER2 FISH. The longest diameters, thus largest available surface areas of the tumors were included in the evaluation. Different regions were marked for morphology and in all immunohistochemical reactions. The regions in the distinct tumors showing different pathological and immunohistochemical appearance were identical (p<0.001). The number of morphologically different tumor regions were more frequent in tumors developing in the young (1.82 vs. 1.48 regions/tumor), and 53.6% of tumors with heterogeneous architecture were in young vs. 39.4% in the elderly. However, regarding HER2 staining, cancers in the young patients have shown greater variability among the different tumor areas (p=0.007). The origin of tumor cells predicting prognosis remains undetermined. Whether the analysis of the expression pattern of the whole tumor is conducted or the minute regions are separately examined and averaged, the same results can be achieved. With the development of molecular techniques and accurate prognostic and treatment information rendered to samples the question may be soon answered.     

A solution thermodynamic study of the Cu(II) and Zn(II) complexes of EBTA: X-ray crystal structure of the dimeric complex [Cu2(EBTA)(H2O)3]2

The copper(II) complex of the acyclic EBTA ligand (H₄EBTA = 1,2-bis(2-aminoethoxy)benzene-N,N,N′,N′-tetraacetic acid) has been prepared and characterized by X-ray analysis. The two copper ions of the dinuclear unit present the same distorted octahedral coordination polyhedra. The EBTA ligand is shared between two copper coordination centres, with the formation of centrosymmetric dimers, which are linked in a supramolecular tridimensional structure via additional interactions through the coordinated waters molecules with adjacent carboxylic oxygen atoms. The stability and protonation constants of EBTA with Cu(II) and Zn(II) ions indicate a higher stability of these complexes with respect to the corresponding complexes with the more flexible EGTA ligand (H₄EGTA = ethyleneglycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid). On the other hand, the lower stability of [Gd(EBTA)]⁻ than [Gd(EGTA)]⁻ results in a decreased overall selectivity (lower K_sel) of EBTA towards Gd(III) and suggests that this complex may undergoes transmetallation reactions under physiological conditions.     

Changes of lactic dehydrogenase activity and combination of its subunits in rat anterior pituitary during puberty and in maturity, as well as during estrous cycle on the actue effect of estradiol and after castration

LDH activity in the female rat anterior pituitary increases substantially at the opening of the vagina, after the gradual increase up to the 90st day no important change occurs. During the estrous cycle activity reaches its peak during the estrus, and lowest in ghe proestrus. Molecular organization of the enzyme shows a change only at the opening of the vagina, i. e. a sudden decrease of H/M ratio occurs, value of which does not change during the estrous cycle. Pituitary LDH activity and subunit ratio in males remains constant during life. LDH activity excess in mature female rat pituitary, being about the double as compared to males, develops at the age of about three months, the difference in H/M ratio however is manifest already during puberty. Anterior pituitary LDH activity and structure of the enzyme are affected by sexual hormones, primarily by estradiol, under physiological conditions, too. After ovariectomy LDH activity decreases gradually. The value before the opening of the vagina to be considered as basal level, develops in the 4th postoperative week. H/M ratio decreases by 20 per cent one week after the operation and shows no change thereafter. Orchidectomy involves but a minor activity and H/M ratio decrease. Experimental findings on activity and subunit ratio are related presumably to prolactin cells and suggest that sexual hormone feedback effects in addition to polypeptide production pituitary metabolism.     

Elemental Analysis of Whole and Protein Separated Blood Serum of Patients with Systemic Lupus Erythematosus and Sjögren’s Syndrome

Data on the effects of selenium supplementation on clinical signs and metabolic profiles in women at risk for intrauterine growth restriction (IUGR) are scarce. This study was designed to assess the effects of selenium supplementation on clinical signs and metabolic status in pregnant women at risk for IUGR. This randomized double-blind placebo-controlled clinical trial was performed among 60 women at risk for IUGR according to abnormal uterine artery Doppler waveform. Participants were randomly assigned to intake either 100 μg selenium supplements as tablet (n = 30) or placebo (n = 30) for 10 weeks between 17 and 27 weeks of gestation. After 10 weeks of selenium administration, a higher percentage of women in the selenium group had pulsatility index (PI) of <1.45) (P = 0.002) than of those in the placebo group. In addition, changes in plasma levels of total antioxidant capacity (TAC) (P < 0.001), glutathione (GSH) (P = 0.008), and high-sensitivity C-reactive protein (hs-CRP) (P = 0.004) in the selenium group were significant compared with the placebo group. Additionally, selenium supplementation significantly decreased serum insulin (P = 0.02), homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (P = 0.02), and homeostatic model assessment for B-cell function (HOMA-B) (P = 0.02) and significantly increased quantitative insulin sensitivity check index (QUICKI) (P = 0.04) and HDL-C levels (P = 0.02) compared with the placebo. We did not find any significant effect of selenium administration on malondialdehyde (MDA), nitric oxide (NO), fasting plasma glucose (FPG), and other lipid profiles. Overall, selenium supplementation in pregnant women at risk for IUGR resulted in improved PI, TAC, GSH, hs-CRP, and markers of insulin metabolism and HDL-C levels, but it did not affect MDA, NO, FPG, and other lipid profiles.Clinical trial registration number http://www.irct.ir: IRCT201601045623N64.     

Synthesis and Enantiomeric Recognition Studies of Optically Active Pyridino‐Crown Ethers Containing an Anthracene Fluorophore Unit

Novel enantiopure pyridino‐18‐crown‐6 ether‐based sensor molecules containing an anthracene fluorophore unit were synthesized. Their enantiomeric recognition abilities toward the enantiomers of 1‐phenylethylamine hydrogen perchlorate (PhEt), 1‐(1‐naphthyl)ethylamine hydrogen perchlorate (NapEt), phenylglycine methyl ester hydrogen perchlorate (PhgOMe), and phenylalanine methyl ester hydrogen perchlorate (PheOMe) were examined in acetonitrile using fluorescence spectroscopy. The sensor molecules showed appreciable enantiomeric recognition toward the enantiomers of NapEt, PhEt, and PhgOMe. The highest enantioselectivity was found in the case of crown ether containing isobutyl groups in the macroring and the enantiomers of NapEt. Chirality 28:562–568, 2016. © 2016 Wiley Periodicals, Inc.