10 research outputs found
In vitro radiographic density of dental posts measured by digital radiography
Objectives This study evaluated the radiopacity of seven commercial root
canal posts.
Digital radiographs of the seven commercial posts and of the same
commercial posts and four artificial aluminum posts inserted in lower
canines were obtained with a CCD-based digital sensor. The radiopacity
of the posts was expressed as mm aluminum/mm material (mmAl).
Subsequently, the radiographs were presented to five trained evaluators
who were asked to rank their acceptability scores as not acceptable,
acceptable, or excellent.
Analysis of variance revealed significant differences in radiopacity
among the posts (P < 0.05). The radiopacities of zirconium and titanium
posts were significantly higher than those of fiber posts (P < 0.05).
The minimum aluminum thickness for acceptance in the root canals was 1.2
mmAl.
All of the examined posts presented satisfactory radiopacity for
clinical application.Ivoclar Vivadent; Ministry of Science and Education of the Republic of
Serbia {[}45005
Membrane Steroid Receptor-Mediated Action of Soy Isoflavones: Tip of the Iceberg
Soy isoflavone's (genistein and daidzein in particular) biological
significance has been thoroughly studied for decades, so we started from
the premise that refreshed investigation approach in this field should
consider identification of their new molecular targets. In addition to
recently described epigenetic aspects of polyphenole action, the cell
membrane constituents-mediated effects of soy isoflavones are worthy of
special attention. Accordingly, the expanding concept of membrane
steroid receptors and rapid signaling from the cell surface may include
the prominent role of these steroid-like compounds. It was observed that
daidzein strongly interacts with membrane estrogen receptors in adrenal
medullary cells. At low doses, daidzein was found to stimulate
catecholamine synthesis through extracellular signal-regulated kinase
1/2 or protein kinase A pathways, but at high doses, it inhibited
catecholamine synthesis and secretion induced by acetylcholine. Keeping
in mind that catecholamine excess can contribute to the cardiovascular
pathologies and that catecholamine lack may lead to depression, daidzein
application promises to have a wide range of therapeutic effects. On the
other hand, it was shown in vitro that genistein inhibits LNCaP prostate
cancer cells invasiveness by decreasing the membrane fluidity along with
immobilization of the androgen receptor containing membrane lipid rafts,
with down regulation of the androgen receptors and Akt signaling. These
data are promising in development of the molecular pharmacotherapy
pertinent to balanced soy isoflavone treatment of cardiovascular,
psychiatric, and steroid-related malignant diseases.Ministry of Science, Education and Technological Development of the
Republic of Serbia {[}173009
The influence of different radiopacifying agents on the radiopacity, compressive strength, setting time, and porosity of Portland cement
The aims of this study were to evaluate the radiopacity, compressive strength, setting time, and porosity of white Portland cement (PC) with the addition of bismuth oxide (Bi2O3), zirconium dioxide (ZrO2), and ytterbium trifluoride (YbF3) after immersion at 37 A degrees C for 7 days in distilled water or phosphate buffer saline. Specimens measuring 8 mm in diameter and 1 mm in thickness were fabricated from PC with the addition of 10, 20, and 30 wt% Bi2O3, ZrO2 or YbF3. ProRoot MTA (Dentsply, Tulsa, OK, USA) and pure PC were used as controls. For radiopacity assessments, specimens were radiographed alongside a tooth slices and an aluminum stepwedge on Extraspeed occlusal dental films (Insight Kodak, Rochester, New York). Mean optical density of each specimen was calculated and used to express radiopacity of the material as an equivalent thickness of aluminum. Compressive strength was measured by using 4-mm diameter and 6-mm high specimens and Universal testing machine. High-pressure mercury intrusion porosimeter (Carlo Erba Porosimeter 2000) was employed to measure the porosity of the specimens. The setting time was measured by using a needle of 100 g in weight. The morphology of specimens was evaluated using a scanning electron microscope (TESCAN Mira3 XMU, USA Inc.). Data were analyzed by one-way ANOVA and post hoc Tukey test (P LT 0.05). The PC with the addition of at least 10 wt% Bi2O3 and 20 wt% ZrO2 or YbF3 demonstrated greater radiopacity value than the recommended 3 mmAl cut-off. ZrO2 and YbF3 increased the compressive strength of PC, but it was not statistically significant (P > 0.05), while Bi2O3 decreased it (P LT 0.05). All radiopacifiers significantly increased the porosity of the experimental cements (P LT 0.05). Bi2O3 extended the setting time of PC (P LT 0.05), whilst ZrO2 and YbF3 did not significantly affect it (P > 0.05). ZrO2 and YbF3 may be used as a suitable alternative to replace Bi2O3 in MTA without influencing its physical properties
THE EFFECTS OF ESTRADIOL AND HUMAN CHORIONIC GONADOTROPIN ON ACTH CELLS IN PERIPUBERTAL FEMALE RATS: A HISTOLOGICAL AND STEREOLOGICAL STUDY
The effects of estradiol (EDP) and human chorionic gonadotropin (HCG) on
histological and stereological features of adrenocorticotropic (ACTH)
cells in peripubertal female rats were examined. The first group of
females received five injections of EDP (0.25 mg/kg b.w.), every second
day from the 4th to 14th day after birth, and was killed at the
peripubertal stage. The second group of females was given two injections
of pregnyl-gonadotrophinum chorionicum (HCG; 50 IU/kg body weight) on
the 36th and 37th days after birth, and it was killed 24 h after the
last treatment. The controls were injected with an equivalent volume of
the corresponding vehicle. ACTH cells were immunohistochemically labeled
and stereologically evaluated. Stereological analysis showed that the
volume of ACTH cells and their volume density in peripubertal females
treated with EDP, were decreased by 15.6\% and 53.8\% (p < 0.05),
respectively, compared to the controls. In HCG-treated animals, the
observed parameters were increased by 39.2\% and 15.4\% (p < 0.05),
respectively, in comparison with the control females. These findings
suggest that the application of EDP or HCG exerted opposite effects on
the stereological features of pituitary ACTH cells.Ministry of Education, Science and Technological Development of the
Republic of Serbia {[}ON 173009
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.
(C) 2014 Elsevier GmbH. All rights reserved.Ministry of Education, Science and Technological Development of the
Republic of Serbia {[}173009
IMMUNO-HISTOMORPHOMETRIC AND -FLUORESCENT CHARACTERISTICS OF GH CELLS AFTER TREATMENT WITH GENISTEIN OR DAIDZEIN IN AN ANIMAL MODEL OF ANDROPAUSE
Somatopause, the complex aspect of andropause, is recognizable by
reduced growth hormone - GH/insulin-like growth factor 1 axis function
in the ageing male. Soy isoflavones (usually genistein and daidzein),
which are known for their beneficial effects in the treatment of ageing
symptoms, are active in the pituitary, as well. The
iromuno-histomorphometric and fluorescent characteristics of pituitary
growth hormone secreting cells, in an animal model of andropause, were
examined after a treatment with genistein or daidzein. Andropausal
Wistar rats were divided into sham operated, orchidectomized and
genistein or daidzein treated orchidectomized groups. Genistein or
daidzein (30 mg/kg/day) were administered subcutaneously for three
weeks, while sham operated and orchidectomized groups received the
vehicle alone. Growth hormone secreting cells were identified by the
percoxidase-antiperoxidase immuno-histochemical, and inmuno-fluorescent
procedure. The main characteristic of growth hormone secreting cells in
soy isoflavones treated groups is a weaker immuno-histochemical staining
and immuno fluorescent signal compared to sham operated and
orchidectomized groups. The growth hormone secreting cell volume in
orchidectomized +genistein or +daidzein groups is by 13.8\% and 11.9\%
(p<0.05) smaller respectively, in comparison with the orchidectomized
group. In orchidectomized +genistein or +daidzein groups, the growth
hormone secreting cells relative volume density is by 62.5\% and 61.0\%
lower (p<0.05) respectively than for the sham operated group, and
decreased by 65.4\% and 64.0\% (p<0.05) respectively, compared to the
orchidectomized group. It can be concluded that chronic genistein or
daidzein treatment, in an animal model of andropause, attenuates
immuno-histomorphometric and fluorescent characteristics of growth
hormone secreting cells.Ministry of Education, Science and Technological Development of the
Republic of Serbia {[}173009
Effects of genistein on stereological and hormonal characteristics of the pituitary somatotrophs in rats
The hypothalamic-pituitary somatotropic system plays a pivotal role in
the regulation of physiological processes and metabolism, which is
modulated by gonadal steroids. Considering that genistein belongs to the
phytoestrogen family and acts via similar mechanisms to estrogens, the
present study was designed to demonstrate whether genistein modulates
the morphofunctional characteristic of somatotrophs {[}growth hormone
(GH) cells] in adult rats in comparison with the effects of estradiol.
In the study, the orchidectomized adult rats were used as an appropriate
model system for testing the effects of this hormone-like substance.
Changes in the pituitary somatotrophs were evaluated histologically and
stereologically, while GH level was determined biochemically. Using
immunolabelling and stereological methods, we showed that orchidectomy
(Orx) provoked the decrease of GH cell volume density. After estradiol
treatment of Orx rats, the most prominent change concerned the pituitary
relative intensity of GH fluorescence and circulating GH level, which
were elevated 77 \% and 4.7-fold, respectively. Clearly, in contrast to
orchidectomy, estradiol treatment enhanced the GH cells activity.
Genistein treatment increased pituitary weight and volume, GH cell
volume density, the total number of GH cells, and GH blood concentration
(1.3-fold) in comparison to the Orx group. Although identical tendencies
followed estradiol and genistein administration, the changes observed
after genistein treatment were milder compared to estradiol treatment.Ministry of Education and Science of Serbia {[}173009
Diosgenin does not express estrogenic activity: a uterotrophic assay
This study assessed the effects of diosgenin on estrogenic activity
using a uterotrophic assay. Immature female rats received diosgenin
orally at doses of 200, 100, or 20 mg/kg body mass; and 17 alpha
ethynylestradiol at doses of 1 or 0.3 mu g/kg, daily, for 3 consecutive
days from day 19 to day 21. Controls were distributed among 2 groups: an
intact control group and a vehicle control group. Animals were
sacrificed 24 h after the last application of diosgenin, estradiol, or
vehicle (22nd day of life). Uterine wet weight, stereological and
histomorphometrical changes, immunohistochemical expression of estrogen
receptor alpha (ER alpha), progesterone receptor (PR), and the
expression of lactoferrin (LF) were examined. Diosgenin did not affect
the uterine wet weight, epithelium height, volume densities of
endometrium, endometrial epithelia, number of endometrial glands, or
histological appearance of vaginal epithelia. ER alpha, PR, and LF
immunostaining intensity were not altered in the animals that received
diosgenin. High-potency reference ER agonist 17 alpha-ethynylestradiol
induced a significant increase in all of the measured parameters, and as
expected, decreased ER alpha immunostaining intensity. Based on these
data, it can be concluded that diosgenin, at doses of 20-200 mg/kg, did
not act as an estrogen agonist in the immature rat uterotrophic assay.Ministry of Education, Science, and Technological Development of the
Republic of Serbia {[}173009
Effects of soy phytoestrogens on pituitary-ovarian function in middle-aged female rats
The aim of this study was to assess the effects of genistein (G) and
daidzein (D) on the histological, hormonal, and functional parameters of
the pituitary-ovarian axis in middle-aged female rats, and to compare
these effects with the effects of estradiol (E), commonly used in the
prevention and treatment of menopausal symptoms. Middle-aged (12 month
old) Wistar female rats subcutaneously received 35 mg/kg of G, or 35
mg/kg of D, or 0.625 mg/kg of E every day for 4 weeks. Each of the
treated groups had a corresponding control group. An intact control
group was also established. G and D did not change the intracellular
protein content within gonadotropic and lactotropic cells, but
vacuolization was observed in all the cell types. In contrast, E caused
an inhibition of gonadotropic and stimulation of lactotropic cells.
Also, ovaries of middle-aged female rats exposed to G or D have more
healthy primordial and primary follicles and less atretic follicles. E
treatment in the ovaries had a mostly negative effect, which is
reflected by the increased number of atretic follicles in all tested
classes. G and D provoked decrease in CuZnSOD and CAT activity, while E
treatment increased MnSOD and decreased CuZnSOD and GSHPx activity. All
the treatments increased serum estradiol and decreased testosterone
levels, while D and E increased the serum progesterone level. In
conclusion, soy phytoestrogens exhibited beneficial effects on
pituitary-ovarian function in middle-aged female rats, as compared to
estradiol.Ministry of Education, Science and Technological Development of the
Republic of Serbia {[}173009