Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.1.1.3 (HSD)
 3,464 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study investigated the influence of thermal cycling on the dentin bond strengths of single-step self-etch adhesive systems. The Absolute, Clearfil Tri-S Bond, G-Bond and One-Up Bond F Plus systems were used. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied to the prepared dentin surfaces, and they were light irradiated according to each manufacturer's instructions. Resin composites were condensed into a mold (4 mm in diameter and 2 mm in height) and light irradiated for 30 seconds. Bonded specimens were divided into three groups and subjected to different storage conditions as follows: 37 degrees C water for 24 hours; 37 degrees C water for 24 hours followed by 10,000 thermal cycles between 5 degrees C and 60 degrees C or 37 degrees C water for 24 hours followed by 20,000 thermal cycles between 5 degrees C and 60 degrees C. Ten samples per group were tested in a shear mode at a crosshead speed of 1.0 mm/minute. Analysis of variance and Tukey's HSD test at the 0.05 significance level were used to compare the three storage conditions for each adhesive system. After 24 hours storage in water, the mean dentin bond strengths ranged from 11.4 MPa to 17.1 MPa. The Clearfil Tri-S Bond system showed the highest bond strength. After 10,000 thermal cycles, the mean bond strengths remained unchanged except for those of the Clearfil Tri-S Bond system, which significantly increased. Significant decreases in bond strength were observed for the Absolute and One-Up Bond F Plus systems after 20,000 thermal cycles. Failure mode was commonly due to adhesive breakdown associated with partial cohesive failure of the adhesive resin. From the results of this study, in terms of simplifying the clinical procedure, the benefit of using single-step self-etch systems might be acceptable.
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PMID:Influence of thermal cycling on dentin bond strengths of single-step self-etch adhesive systems. 1728 32

The epithelial cells of the choroid plexus (CP) are responsible for cerebrospinal fluid (CSF) secretion into the ventricles of the brain. The balance between CSF production and drainage, in part, facilitates a normal intracranial pressure. The secretion of Na(+) and anions by the CP creates an osmotic gradient driving water into the ventricles. This is opposite to classical Na(+) transporting tissues, such as the kidney, where Na(+) and water reabsorption is mediated by 11beta-hydroxysteroid dehydrogenase type 2 that protects the mineralocorticoid receptor by abrogating active cortisol to inactive cortisone. In the human ocular ciliary epithelium, Na(+) and water secretion is dependent on a novel mediator of ciliary epithelial Na(+) transport, 11beta-HSD type 1 (11beta-HSD1), that generates intraocular cortisol. In a mechanism analogous to that of the embryologically related ocular ciliary epithelium, we propose that autocrine regulation of intracranial cortisol is dependent on 11beta-HSD1 expression in the CP epithelial cells. By conducting immunolocalisation studies on brains from New Zealand White Albino rabbits, we defined the expression of 11beta-HSD1 in the secretory CP epithelial cells. Enzyme assays performed on intact rabbit CP whole tissue explants confirmed predominant 11beta-HSD1 activity, generating cortisol that was inhibited by glycyrrhetinic acid (an 11beta-HSD inhibitor). Using the real time-polymerase chain reaction, rabbit CP tissue was found to express levels of 11beta-HSD1, glucocorticoid receptor alpha and serum and glucocorticoid-regulated kinase 1 mRNA comparable to that expressed in rabbit ocular ciliary body, thereby highlighting the similarity between these two tissues. Furthermore, an enzyme-linked immunosorbent assay of rabbit CSF revealed a median cortisol concentration of 1.7 nmol/l (range 1.4-4.3 nmol/l, n = 9). Our data have identified a functional 11beta-HSD1 within the CP, mediating intracranial cortisol bioavailability. Expression of 11beta-HSD1 may be fundamental in the regulation of CSF secretion and the local generation of cortisol may represent a pathophysiological mechanism underlying cortisol-dependent neuroendocrine diseases.
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PMID:Corticosteroids, 11beta-hydroxysteroid dehydrogenase isozymes and the rabbit choroid plexus. 1762 Jan 3

Acrylamide (ACR) is a neurotoxicant known to produce peripheral neuropathy in rats and humans, but little is known of its potential for producing cognitive or motivational alterations. Chronic exposure to low doses of ACR as a food contaminant is known to occur widely in humans. This research evaluated the effects of daily ACR exposure on food-motivated behavior, with exposures beginning prenatally on gestation day 6 and continuing through approximately postnatal day (PND) 85. Plug-positive Fischer 344 dams (9-10 per dose) were gavaged daily with 0, 0.1, 0.3, 1.0 or 5.0mg/kg/day ACR. On PNDs 1-22, pups were gavaged with the same dose their dam had received. On PND 22, pups were weaned and pair-housed with a same-sex littermate and ACR exposure continued at 0, 1, 3, 10 and 50ppm via drinking water. One male and one female pup per litter were tested in an operant chamber under a progressive ratio (PR) schedule of food reinforcement from approximately 6 to 12 weeks of age. Results over 6 weeks of testing indicated a significant treatment effect of ACR on number of reinforcers earned, with Tukey HSD post hoc tests revealing significantly fewer reinforcers earned in the 5.0mg/kg/day dose group than in controls. A significant effect of ACR on response rate was also observed, with the Tukey HSD post hoc tests revealing a significantly lower response rate in the 5.0mg/kg/day group than in controls. No effects of ACR were observed on post-reinforcement pause. These data suggest that daily ACR exposure at 5.0mg/kg/day can produce measurable decrements on aspects of food-motivated behavior.
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PMID:Effects of chronic low-dose acrylamide exposure on progressive ratio performance in adolescent rats. 1772 Feb 46

Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf.) has been used as a traditional Chinese medicine for dysfunction of the endocrine system. However, there have been few studies on the effects of adlay seed on the endocrine system. In the present study, both the in vivo and in vitro effects of methanolic extracts of adlay hull (AHM) on progesterone synthesis were studied. AHM was partitioned with four different solvents: water, 1-butanol, ethyl acetate, and n-hexane. Four fractions, namely, AHM-Wa (water fraction), AHM-Bu (1-butanol fraction), AHM-EA (ethyl acetate fraction), and AHM-Hex (n-hexane fraction), were respectively obtained. Granulosa cells (GCs) were prepared from pregnant mare serum gonadotropin-primed immature female rats and were challenged with different reagents, including human chorionic gonadotropin (hCG; 0.5 IU/ml), 8-bromo-adenosine-3',5'-cyclic monophosphate (8-Br-cAMP; 0.1 mM), forskolin (10 microM), 25-OH-cholesterol (10 microM), and pregnenolone (10 microM), in the presence or absence of AHM (100 microg/ml). The functions of steroidogenic enzymes, including protein expression of the steroidogenic acute regulatory protein (StAR), cytochrome P450 side chain cleavage enzyme (P450scc), protein kinase A (PKA), and aromatase activity, were investigated. The expression of StAR mRNA was also explored by using real-time reverse transcription-polymerase chain reaction. In the in vivo study, AHM decreased plasma progesterone and estradiol levels after an intravenous injection of AHM (2 mg/ ml/kg). In the in vitro studies, AHM decreased progesterone and estradiol via inhibition of (i) the cAMP-PKA signal transduction pathway, (ii) cAMP accumulation, (iii) P450scc and 3beta-HSD enzyme activities, (iv) PKA, P450scc and StAR protein expressions and StAR mRNA expression, and (v) aromatase activity in rat GCs. These results suggest that AHM decreased the production of progesterone via mechanisms involving the inhibition of the cAMP pathway, enzyme activities, and the protein expressions of P450scc and StAR in rat GCs.
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PMID:Effects of adlay (Coix lachryma-jobi L. var. ma-yuen Stapf.) hull extracts on the secretion of progesterone and estradiol in vivo and in vitro. 1789 26

This in vitro study compared the marginal and internal adaptation of bulk-filled Class I and cuspal coverage direct resin composite restorations filled with different types of adhesive restorative systems and different thicknesses of bonding agent. Seventy-two intact, caries-free, freshly extracted human molars were randomly divided into 12 groups of six teeth each, according to the type of cavity (Class I [I] or Cuspal Coverage [C]), adhesive restorative system (SE Bond/Clearfil AP-X [SE] or Prime&Bond NT/Spectrum TPH [PB]) and thickness of bonding agent (normal or thick layer) in Class I restorations. Standardized Class I and Cuspal coverage cavities with enamel outer margins were prepared and restored with the corresponding type and thickness of bonding agent and respective resin composite. The resin composite was placed and polymerized in one increment (bulk filling). Dentinal fluid was simulated using 1:3 diluted horse serum and fed into the pulp chamber both during restoration and stressing. In six of the 12 groups, the restorations were subjected to 1.2 million mechanical occlusal cycles (maximum force 49 N; frequency 1.7Hz) and 3,000 simultaneous thermal cycles (5-50-5 degrees C). Marginal adaptation before and after mechanical and thermal stressing was assessed by using the replica technique and quantitative evaluation under SEM at 200x magnification. The teeth were dissected in a mesio-distal direction with a slow rotating diamond disc under water cooling, and the internal adaptation was also assessed by using the replica technique under the conditions described. Statistical evaluation of the continuous margin at the external and internal interface was performed with one-way analysis of variance (ANOVA) and Tukey's Studentized Range (HSD) test (p = 0.05). Even though Cuspal coverage restorations (SE- C: 96.89 +/- 1.83 and PB- C: 97.15 +/- 2.93) exhibited statistically significantly better external adaptation than Class I restorations (SE- I: 63.95 +/- 12.82 and PB- I 64.74 +/- 14.62) before stressing, there was no statistically significant difference after mechanical and thermal stressing (SE- C: 76.35 +/- 18.53 and PB- C: 76.02 +/- 12.49 SE- I: 54.67 +/- 10.82 and PB- I: 59.94 +/- 15.20). After stressing, SE Bond Cuspal coverage restorations (SE- C: 96,72 +/- 3,26) exhibited superior internal adaptation compared to SE Bond Class I restorations (SE- I: 57.83 +/- 12.91). No difference was observed in internal adaptation between Prime&Bond NT Cuspal coverage and Class I restorations (PB- C:36.46 +/- 21.82, PB- I: 38.71 +/- 6.76). In Class I restorations, the increased thickness in bonding did not improve the marginal and internal adaptation either before or after stressing. Bulk-filled direct resin composite Cuspal coverage restorations exhibited marginal adaptation similar to bulk-filled direct resin composite Class I restorations. The internal adaptation of Cuspal coverage SE Bond/Clearfil AP-X restorations was superior to all the other groups tested.
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PMID:Marginal and internal adaptation of bulk-filled Class I and Cuspal coverage direct resin composite restorations. 1791 Feb 30

The purpose of this study was to evaluate the influence of irradiation time on volumetric change and flexural properties of flowable resins. Four commercially available flowable resins were employed. For volumetric shrinkage measurement, resin pastes were inserted into a mold (2 mm in height, 4 mm in diameter) and put into a water-filled dilatometer. This was followed by light irradiation for 10, 20, or 30 seconds at 600 mW/cm2. Volumetric shrinkage of the specimens was then determined from the change in the height of water meniscus, and the percentage volumetric change thereof was calculated. For flexural strength measurement, resin pastes were filled into a stainless steel mold (25 x 2 x 2 mm), and the middle one-third of the specimen was first irradiated. The remaining two-thirds were irradiated under the same irradiation conditions as volumetric shrinkage measurement. After 24-hour storage in 37 degrees C water, three-point flexural tests were performed with a span length of 20 mm at a crosshead speed of 1.0 mm/min. One-way ANOVA followed by Tukey's HSD test were used for statistical analysis. For all materials tested except Estelite Flow Quick, both volumetric shrinkage and flexural strength increased with longer light irradiation time. Results of this study indicated that both volumetric shrinkage and flexural properties were influenced by light irradiation time and resin composite type.
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PMID:Influence of irradiation time on volumetric shrinkage and flexural properties of flowable resins. 1820 96

The purpose of this in vitro study was to compare the shear bond strengths of resin, glass-ionomer, and ceramic-based core materials to all ceramic discs. Five core materials (Core max, Sankin; Clearfil AP-X, Kuraray; Empress Cosmo, Ivoclar-Vivadent; Photocore, Kuraray; Dyract Extra, Dentsply) were prepared as discs 10 mm in diameter and 2 mm in height according to the manufacturer's instructions. Ten disc specimens per group were prepared, and dentin served as the control. All resin specimens were embedded in autopolymerizing acrylic resin, with one surface facing up. All ceramic discs (IPS Empress I, Ivoclar-Vivadent) 3 mm in diameter and 2 mm in height were prepared and bonded to core specimens with a dual-curing luting resin cement (Variolink II, Vivadent). Specimens were stored in distilled water at 37 degrees C. Shear bond strength of each sample was measured after 24 h using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed with one-way analysis of variance and Tukey HSD tests (alpha = 0.05). Shear bond strength varied significantly depending on the core material used (p < 0.05). Clearfil AP-X and Photocore showed the highest shear bond strength value while Empress Cosmo provided the lowest (p < 0.05). There were no statistically significant differences among Clearfil AP-X, Photocore, and Core-Max (p > 0.05). And also there were no statistically significant differences between Dyract Extra and the control group (p > 0.05). In vitro shear bond strengths of ceramic discs bonded to resin-based core materials showed higher bond strength values than ceramic-based core material.
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PMID:Bond strength of adhesively luted ceramic discs to different core materials. 1843 56

This study evaluated the tensile bond strengths of three adhesive/composite core materials to bovine dentin using three different curing units. Bovine dentin surfaces were ground with 600-grit SiC paper. Bonding area was demarcated with a vinyl tape (4-mm-diameter hole). Three adhesive/composite core systems--S6054 (experimental), UniFil Core, and Clearfil DC Core Automix--were used with three curing units--Curing Light XL3000 (quartz-tungsten-halogen), Hyper Lightel (high-power quartz-tungsten-halogen), and LEDemetronl (blue light-emitting diode)--according to manufacturers' instructions. After 24 hours of storage in water at 37 degrees C, tensile bond strengths were measured at a crosshead speed of 2 mm/min. Results were statistically analyzed with one-way ANOVA and Tukey's HSD test (p < 0.05). Highest tensile bond strength was obtained using Clearfil DC Core Automix with Hyper Lightel.
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PMID:Dentin bond strengths of three adhesive/composite core systems using different curing units. 1854 Mar 91

Single-step self-etch adhesive systems have been developed to simplify and shorten bonding procedures. With the gain in popularity of these simplified systems, their reliability has become a focus of interest. The purpose of this study was to determine the effect of adhesive application method on enamel bond strength. Two commercial single-step self-etch adhesive systems, Clearfil tri-S Bond, and G-Bond, were used. Bovine mandibular incisors were mounted in self-curing resin and the facial enamel surfaces were ground wet on 600-grit SiC paper. Adhesives were only applied without agitation (inactive) or were agitated by a brush (active), and resin composites were condensed into the mold on the enamel surface and light-activated. Ten specimens per test group were stored in water at 37 degrees C for 24 h, then shear-tested at a cross-head speed of 1.0 mm/min. Two-way ANOVA followed by the Tukey HSD test were used. The bond strengths for active application were higher than those for inactive application. Significant differences were found for both adhesive systems. From the results of this study, active application of single-step self-etch adhesive may help to ensure the creation of a roughened enamel surface and enhance the penetration of resin monomer into the subsurface demineralized enamel.
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PMID:Effect of adhesive application methods on bond strength to bovine enamel. 1858 8

The potential health hazard of the large amounts of Lead that occurs in canned baby food, domestic water from lead-lined tanks and, in printing and petroleum industries. Lead acetate administration at a does of 8 mg/kg body weight for 21 days resulted a significant increase in adrenal steroidogenic enzyme (Delta5-3beta- HSD) and serum levels of corticosterone, while serum levels of testosterone, FSH, LH and testicular spermatogenesis were decreased in albino rats. But lead-treated rats received exogenous testosterone for the last 14 days of lead treatment, showed prevention of adrenocortical hyperactivity by decreasing adrenal Delta5-3beta-HSD activity and serum level of corticosterone. Testosterone administration also increased serum level of testosterone, FSH and LH along with spermatogenesis. The results suggest that testosterone supplementation in lead-treated rats protects adrenocortical activity and testicular spermatogenesis.
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PMID:Protection of adrenal and male gonadal functions by androgen in lead-treated rats. 1860 1


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