ACTH-producing cells of 21-day-old rat fetuses after maternal dexamethasone exposure

Adrenocorticotrophic hormone (ACTH) is essential for developmental maturation of numerous organ systems during the fetal period and for adaptation to environmental challenges. Immunocytochemical and stereological methods were used in the present study to examine the effects of dexamethasone (Dx) administration during pregnancy on fetal rat pituitary ACTH-producing cells. Doses of 0.5, 0.5 and 1.0 mg Dx/kg body weight/day were given to the dams on 3 consecutive days starting on day 16 of gestation. Morphometric analysis of the ACTH-producing cells of fetuses at 21 days of gestation revealed significant inhibition by 24% and 27%, respectively, of cell volume and cell number after maternal Dx administration, whereas the volume of cell nuclei and volume density of ACTH-stained cells were insignificantly decreased. Immunocytochemical analysis showed reduced numbers, sizes and immunopositivity of ACTH cells of 21-day-old fetuses from Dx-treated dams as compared with the control group. Maternal Dx treatment in the period of intense differentiation of the hypothalamo-hypophyseal-adrenal system had an inhibitory effect on fetal function and proliferative activity of ACTH-producing cells at 21 days of gestation. Thus, inhibition of activity of fetal ACTH-producing cells may lead to adrenal suppression, modified activity of the hypothalamo-pituitary-adrenal axis and reduced body weight possibly causing lasting functional abnormalities.     

The effects of sex steroids on thyroid C cells and trabecular bone structure in the rat model of male osteoporosis

Androgen deficiency is one of the major factors leading to the development of osteoporosis in men. Since calcitonin (CT) is a potent antiresorptive agent, in the present study we investigated the effects of androgen deficiency and subsequent testosterone and estradiol treatment on CT-producing thyroid C cells, skeletal and hormonal changes in middle-aged orchidectomized (Orx) rats. Fifteen-month-old male Wistar rats were either Orx or sham-operated (SO). One group of Orx rats received 5 mg kg⁻¹ b.w. testosterone propionate (TP) subcutaneously, while another group was injected with 0.06 mg kg⁻¹ b.w. estradiol dipropionate (EDP) once a day for 3 weeks. A peroxidase–antiperoxidase method was applied for localization of CT in the C cells. The studies included ultrastructural microscopic observation of these cells. The metaphyseal region of the proximal tibia was measured histomorphometrically using an imagej public domain image processing program. TP or EDP treatment significantly increased C cell volume (Vc), volume densities (Vv) and serum CT concentration compared with the Orx animals. Administration of both TP and EDP significantly enhanced cancellous bone area (B.Ar), trabecular thickness (Tb.Th) and trabecular number (Tb.N) and reduced trabecular separation (Tb.Sp). Serum osteocalcin (OC) and urinary Ca concentrations were significantly lower after these treatments in comparison with Orx rats. These data suggest that testosterone and estradiol treatment in Orx middle-aged rats affect calcitonin-producing thyroid C cells, which may contribute to the bone protective effects of sex hormones in the rat model of male osteoporosis.     

Exposure to dexamethasone reduces pituitary volume and gonadotropic cell number in rat fetuses

Overexposure to glucocorticoids during the fetal period induces changes in developmental processes in various fetal tissues. The aim of this study was to investigate the effects of the synthetic glucocorticoid, dexamethasone (Dx), on pituitary volume and gonadotropic cells during a critical period of pituitary development. The effects of Dx on stereological parameters of the pituitary gland and FSH and LH cells were investigated in 19 and 21-day old fetuses. On day 16 of pregnancy, the experimental dams received 1.0 mg Dx/kg b.w. subcutaneously, followed by 0.5 mg Dx/kg b.w./day on days 17 and 18 of gestation. The control gravid females received the same volume of saline. FSH and LH cells were stained immunohistochemically by the peroxidase–antiperoxidase method (PAP). In 19-day old fetuses, exposure to Dx caused a significant decrease of pituitary volume, estimated by Cavalieri's principle. Also, the total number of FSH and LH cells per pituitary, determined by physical fractionator counting technique, was significantly reduced. These changes persisted until fetal day 21. Volume densities and numerical densities of FSH and LH cells after exposure to Dx in 19 and 21-day old fetuses remained unaffected. Our results suggest that altered stereological parameters in pituitary gland after exposure to dexamethasone in fetal period could be long-lasting.     

Photodynamic antibacterial effect of graphene quantum dots

Synthesis of new antibacterial agents is becoming increasingly important in light of the emerging antibiotic resistance. In the present study we report that electrochemically produced graphene quantum dots (GQD), a new class of carbon nanoparticles, generate reactive oxygen species when photoexcited (470 nm, 1 W), and kill two strains of pathogenic bacteria, methicillin-resistant Staphylococcus aureus and Escherichia coli. Bacterial killing was demonstrated by the reduction in number of bacterial colonies in a standard plate count method, the increase in propidium iodide uptake confirming the cell membrane damage, as well as by morphological defects visualized by atomic force microscopy. The induction of oxidative stress in bacteria exposed to photoexcited GQD was confirmed by staining with a redox-sensitive fluorochrome dihydrorhodamine 123. Neither GQD nor light exposure alone were able to cause oxidative stress and reduce the viability of bacteria. Importantly, mouse spleen cells were markedly less sensitive in the same experimental conditions, thus indicating a fairly selective antibacterial photodynamic action of GQD.     

The most frequent hormone dysfunctions in juvenile bleeding

The main goal of this study was to investigate the precise hormone dysfunction that leads to dysfunctional uterine bleeding (DUB) in adolescent girls so that, with the appropriate therapy, the occurrence of organic dysfunctions of their reproductive function can be prevented. This study included 70 adolescents with DUB aged 14.70 +/- 1.70 and 30 healthy adolescents aged 13.7 +/- 1.83. Hormone examinations indicated the presence of three typical endocrinological findings of the adolescents with DUB: the first group with FSH values within the normal range, but low LH values, the lower value of estradiol and absence of hyperandrogenism; the second group with higher LH values and normal FSH values but one third with hyperandrogenism; and the third group with normal FSH and LH values, but with hyperinsulinemia and hyperandrogenism. Comparing the hormone values obtained in the control group and the group with DUB, we have concluded that hyperandrogenism, hyperinsulinemia, lower values of progesterone, and dysfunctions in secretion of gonadotropin are statistically important factors for the origin of juvenile bleeding.     

The phytoestrogen genistein prevents trabecular bone loss and affects thyroid follicular cells in a male rat model of osteoporosis

As a major phytoestrogen of soy, genistein effectively prevents bone loss in both humans and rat models of osteoporosis. However, although the bone‐sparing effects of genistein are achieved directly through estrogen receptors, its mode of action on bone by modulation of other endocrine functions is not entirely clear. Thus, thyroid hormones and calcitonin (CT ) have an essential influence on bone metabolism. Besides its action on bones, in this study we examined the effect of genistein on the activity of two different endocrine cell populations, thyroid follicular and C‐cells. Fifteen‐month‐old Wistar rats were either bilaterally orchidectomized (Orx) or sham‐operated (SO ). Two weeks after surgery, half of the Orx rats were treated chronically with 30 mg kg^?1 b.w. genistein (Orx + G) subcutaneously (s.c.) every day for 3 weeks, while the remaining Orx rats and the SO rats were given the same volume of sterile olive oil to serve as controls. For histomorphometrical analysis of the trabecular bone microarchitecture an ImageJ public domain image processing programme was used. Thyroid sections were analysed histologically and stereologically after visualization of follicular and C‐cells by immunohistochemical staining for thyroglobulin and CT . Thyroid follicular epithelium, interstitium, colloid and CT ‐immunopositive C‐cells were examined morphometrically. Serum concentrations of osteocalcin (OC ), triiodothyronine (T₃), thyroxine (T₄) and CT were determined as well as urinary calcium (Ca²⁺) concentrations. Genistein treatment significantly increased cancellous bone area (B.Ar), trabecular thickness (TbTh) and trabecular number (TbN) (P  < 0.05), but trabecular separation (Tb.Sp) was decreased (P  < 0.05) compared with control Orx rats. In the thyroid, genistein treatment significantly elevated the relative volume density (Vv) of the follicular cells (P  < 0.05) compared with Orx, whereas Vv of the colloid was lower (P  < 0.05) than in the Orx. Evaluation of the biochemical parameters showed significant reductions in serum OC , T₃, T₄ and urinary Ca²⁺ concentrations (P  < 0.05), compared with Orx rats. These data indicate that genistein treatment improves the trabecular microarchitecture of proximal tibia, induces histomorphometrical changes in thyroid glands, and decreases circulating thyroid hormone levels in orchidectomized rat model of male osteoporosis.     

Low-level Er:YAG laser irradiation enhances osteoblast proliferation through activation of MAPK/ERK

Although the use of high-level Er:YAG laser irradiation has been increasing in periodontal and peri-implant therapy, the effects of low-level Er:YAG laser on surrounding tissues and cells remain unclear. In the present study, the effects of low-level Er:YAG laser irradiation on osteoblast proliferation were investigated. Cells of the osteoblastic cell line MC3T3-E1 were treated with low-level Er:YAG laser irradiation with various combinations of laser settings (fluence 0.7–17.2 J/cm²) and in the absence or presence of culture medium during irradiation. On day 1 and/or day 3, cell proliferation and death were determined by cell counting and by measurement of lactate dehydrogenase (LDH) levels. Further, the role of mitogen-activated protein kinase (MAPK) pathways in laser-enhanced cell proliferation was investigated by inhibiting the MAPK pathways and then measuring MAPK phosphorylation by Western blotting. Higher proliferation rates were found with various combinations of irradiation parameters on days 1 and 3. Significantly higher proliferation was also observed in laser-irradiated MC3T3-E1 cells at a fluence of approximately 1.0–15.1 J/cm², whereas no increase in LDH activity was observed. Further, low-level Er:YAG irradiation induced the phosphorylation of extracellular signal-regulated protein kinase (MAPK/ERK) 5 to 30 min after irradiation. Although MAPK/ERK 1/2 inhibitor U0126 significantly inhibited laser-enhanced cell proliferation, activation of stress-activated protein kinases/Jun N-terminal kinase (SAPK/JNK) and p38 MAPK was not clearly detected. These results suggest that low-level Er:YAG laser irradiation increases osteoblast proliferation mainly by activation of MAPK/ERK, suggesting that the Er:YAG laser may be able to promote bone healing following periodontal and peri-implant therapy.     

Henna tattoo contact dermatitis — a report of four cases and brief review of the selected literature

Temporary henna tattoos have recently become increasingly popular, especially among teenagers. Combining henna with other colouring agents such as para-phenylenediamine (PPD) may increase its potential for contact sensitization, cross-reaction to related compounds, as well as life-long allergy. Several cases of contact dermatitis from temporary tattoos with black henna have been reported in the literature. We present our experiences with 4 pediatric cases of allergic contact dermatitis induced by henna tattooing and give a brief review of the literature. The agent responsible for contact allergy was proven to be PPD in 3 patients, and in one patch testing revealed positive reactions to PPD and benzocaine, as well as to wool alcohols, nickel sulphate and potassium dichromate, to previously used hair dye—all being of clinical relevance.