Morphological and functional changes in pituitary‐thyroid axis following prolonged exposure of female rats to constant light

Light regulates numerous physiological functions and synchronizes them with the environment, in part by adjusting secretion of different hormones. We hypothesized that constant light (CL) would disturb pituitary‐thyroid axis. Our aim was to determine morphological and functional changes in this endocrine system in such extreme conditions and, based on the obtained results, to propose the underlying mechanism(s). Starting from the thirtieth postnatal day, female Wistar rats were exposed to CL (600 lx) for the following 95 days. The controls were maintained under the regular laboratory lighting conditions. After decapitation, pituitaries and thyroids were prepared for further histomorphometric, immunohistochemical, and immunofluorescence examinations. Concentration of thyroid stimulating hormone (TSH), total T₄ and T₃ (TH) were determined. Thyroid tissue of light‐treated rats was characterized by microfollicular structure. We detected no change in total thyroid volume, localization and accumulation of thyroglobulin, thyroid peroxidase, and sodium‐iodide symporter in the follicular epithelium of CL rats. The volume of follicular epithelium and activation index were increased, while volume of the colloid and serum levels of TH decreased. In the pituitary, the relative intensity of TSH β‐immunofluorescence signal within the cytoplasm of thyrotrophs increased, but their average cell volume and the relative volume density decreased. Serum TSH was unaltered. We conclude that exposure of female rats to CL induced alterations in pituitary‐thyroid axis. Thyroid tissue was characterized by microfollicular structure. Serum TH levels were reduced without accompanying increase in serum TSH. We hypothesize that increased secretion and clearance of TH together with unchanged or even decreased hormonal synthesis, resulted in decreased serum TH levels in CL group. We assume this decrease consequently led to increased synthesis and/or accumulation of pituitary TSH. However, decreased average TSH cell volume and relative volume density, together with unchanged serum TSH, point to additional, negative regulation of thyrotrophs. J. Morphol. 275:1161–1172, 2014. © 2014 Wiley Periodicals, Inc.     

Transformation of Probiotic Yeast and Their Recovery from Gastrointestinal Immune Tissues Following Oral Gavage in Mice

Development of recombinant oral therapy would allow for more direct targeting of the mucosal immune system and improve the ability to combat gastrointestinal disorders. Adapting probiotic yeast in particular for this approach carries several advantages. These strains have not only the potential to synthesize a wide variety of complex heterologous proteins but are also capable of surviving and protecting those proteins during transit through the intestine. Critically, however, this approach requires expertise in many diverse laboratory techniques not typically used in tandem. Furthermore, although individual protocols for yeast transformation are well characterized for commonly used laboratory strains, emphasis is placed here on alternative approaches and the importance of optimizing transformation for less well characterized probiotic strains. Detailing these methods will help facilitate discussion as to the best approaches for testing probiotic yeast as oral drug delivery vehicles and indeed serve to advance the development of this novel strategy for gastrointestinal therapy.     

Duinefontein 2: an Acheulean site in the Western Cape Province of South Africa.

Excavations at Duinefontein (DFT) 2 near Cape Town, South Africa have recovered numerous stone artefacts and animal bones on an ancient surface sealed within iron-stained eolian sands. U-series analysis of an overlying calcrete places the sands before 150 ka ago, while the large mammal taxa imply an age between 400 and 200 ka ago. The artefacts include a classic Acheulean handaxe and probable biface shaping flakes that support this age estimate. The principal mammalian species are long-horned buffalo, black wildebeest, greater kudu, Cape zebra, and grysbok/steenbok, which imply a grass-and-bush mosaic instead of the historic small-leafed shrubland.Hippopotamus and reedbuck indicate that water stood nearby, probably in dune swales. The large mammal bones are mostly vertebrae and other axial elements, often in near-anatomical order. Both proximal and distal appendicular elements are rare. Bones with carnivore damage are common, but ones with stone tool marks are scarce. The sum suggests a water-edge attritional death site where people played a minimal role and carcasses were disarticulated mainly by carnivore feeding and by trampling. Stone tool marks tend to be equally rare at other Acheulean attritional death sites, and the implication may be that Acheulean people rarely obtained large mammals, whether by hunting or scavenging. Human scavengers at DFT2 would not have encountered a disproportionate number of distal (versus proximal) limb elements, and it follows that the tendency for distal elements to dominate many archeological assemblages need not reflect scavenging versus hunting. Even if DFT2 was not itself a locus of intense human activity, it provides a useful baseline for evaluating bone damage, skeletal part representation, and other variables at sites where people were deeply involved.     

Membrane Fluidity, Invasiveness and Dynamic Phenotype of Metastatic Prostate Cancer Cells after Treatment with Soy Isoflavones

Soy isoflavones represent hopeful unconventional remedies in the therapy of prostate cancer. The aim of our study was to determine the effects of genistein and daidzein on the parameters that reflect metastatic potential, membrane fluidity, invasiveness and dynamic phenotype in Matrigel of LNCaP and PC-3 prostate cancer cells. Cell viability tests, using a wide range of concentrations of soy isoflavones (6–75 μg/ml for 72 h), were conducted to determine their IC₅₀ concentrations. Electron paramagnetic resonance investigations of prostate cancer cell membrane fluidity were performed at IC₅₀ concentrations of genistein and daidzein (12.5 and 25 μg/ml, respectively, for 10 min). Genistein provoked significant increases in the membrane order parameter (which is reciprocally proportional to membrane fluidity) of 0.722 ± 0.006 (LNCaP), 0.753 ± 0.010 (LNCaP + genistein), 0.723 ± 0.007 (PC-3) and 0.741 ± 0.004 (PC-3 + genistein); however, no such effects were observed for daidzein. While both genistein and daidzein reduced the proliferation of prostate cancer cells at their respective IC₅₀ concentrations, during the 72 h of incubation only genistein provoked effects on the dynamic phenotype and decreased invasiveness. The effect was more evident in PC-3 cells compared to LNCaP cells. Our results imply that (1) invasive activity is at least partially dependent on membrane fluidity, (2) genistein may exert its antimetastatic effects by changing the mechanical properties of prostate cancer cells and (3) daidzein should be applied at higher concentrations than genistein in order to achieve pharmacological effects.     

Thyroid C cells of middle-aged rats treated with estradiol or calcium

 The structure and function of C cells of middle-aged female rats (14-months old) treated with estradiol dipropionate (EDP), calcium (Ca) or a combination of EDP+Ca were studied. A stereological method was used to determine the volume of calcitonin (CT)-immunoreactive C cells and their nuclei, and the relative volume density and mean number of the C cells per section were calculated. Serum levels of CT, osteocalcin, parathyroid hormone (PTH), and β-estradiol were also measured. A significant decrease in body weight of the rats treated with EDP or EDP+Ca was observed. These treatments led to a significant decrease in cellular and nuclear volumes, relative volume density, and mean number of C cells per section, in comparison with the corresponding controls. A reduction of the serum level of CT, PTH, and osteocalcin was also recorded in EDP- and EDP+Ca-treated animals. No statistically significant differences between Ca- and vehicle-injected rats, with regard to all morphometric C cell parameters and biochemical values determined, were seen. However, a conspicuous degranulation of the C cells and decreased immunoreactivity for CT in the Ca-receiving group, which could be interpreted as the signs of increased activity of these cells, were noticed. This effect of Ca was also observed in rats injected with EDP and Ca in combination, when the inhibitory effect of EDP on C cell function was less noticeable than in the group treated with EDP alone. Accepted: 29 July 1997     

Arenophthalide A: A new phthalide glycoside from Helichrysum arenarium roots

Spectral data and degradations were used to determine the structure of arenophthalide A, a glycoside of the formula C₁₉H₂₄O₉, isolated from the roots of Helichrysum arenarium. Structure I was assigned to the compound.