Metabolism of triglyceride-rich lipoproteins and lipid transfer to high-density lipoprotein in young obese and normal-weight patients with polycystic ovary syndrome

Objective: To clarify whether the metabolism of triglyceride-rich lipoproteins and lipid transfer to high-density lipoprotein (HDL) are altered in patients with polycystic ovary syndrome (PCOS). Design: Case control study. Setting: Endocrinology clinics. Patient(s): Eight normal-weight (NW) and 15 obese (013) patients with PCOS were compared with 10 NW and 10 Ob women without PCOS paired for age and body mass index. Intervention(s): Determination of triglyceride-rich lipoprotein metabolism and lipid transfer to HDL. Main Outcome Measure(s): Participants were injected triglyceride-rich emulsions labeled with (14)C-cholesteryl esters and (3)H-triglycerides and the fractional clearance rate (FCR, in min(-1)) of labels was determined. Lipid transfer from artificial nanoemulsions to HDL was performed by incubating radioactively labeled lipid nanoemulsions with plasma during 1 hour, followed by radioactive counting of HDL-containing supernatant after chemical precipitation. Result(s): Lipolysis estimated by triglyceride FCR was equal in PCOS groups (NW = 0.043 +/- 0.032, Ob = 0.033 +/- 0.009) and respective controls (NW = 0.039 +/- 0.015, Ob = 0.044 +/- 0.019). However, the remnant removal as estimated by cholesteryl ester FCR was reduced in both PCOS groups (NW = 0.005 +/- 0.006, Ob = 0.005 +/- 0.005) compared with controls (NW = 0.016 +/- 0.006, Ob = 0.011 +/- 0.072). Lipid transfer rates were not different among groups, but triglyceride transfer rates were positively correlated with homeostasis model assessment estimate of insulin resistance in PCOS. Conclusion(s): PCOS patients showed decreased removal of atherogenic remnants even when fasting glucose was <100 mg/dL. This reinforces the usefulness of the measures taken to prevent cardiovascular events in PCOS patients. (Fertil Steril (R) 2010;93:1948-56. (C)2010 by American Society for Reproductive Medicine.)

HDL concentration, lipid transfer to HDL, and HDL size in normolipidemic nonobese menopausal women

Objective: To determine the impact of menopause on lipid transfer from donor lipoproteins to high-density lipoproteins (HDLs)-a process that is related to the protective function of HDL-and the size of HDL particles. Method: Plasma from 22 prernenopausal and 18 postmenopausal nonobese, normolipidemic women paired for age (40-50 years) was incubated in an artificial nanoemulsion labeled with radioactive lipids. Then the HDL fraction was assessed for radioactivity; the percentage of radioactive lipids transferred from the nanoemulsion to HDL was determined; and the size of HDL particles was measured by laser light scattering. Results: There were no differences between the 2 groups in serum concentration of HDL cholesterol (61 12 mg/dL vs 61 +/- 14 mg/dL) or apolipoprotein A(1) (1.5 +/- 0.3 g/L vs 1.5 +/- 0.2 g/L); lipid transfer to HDL; or size of HDL particles (8.8 +/- 0.8 vs 9.0 +/- 0.5 nm). Conclusion: Menopause was not found to affect HDL cholesterol plasma concentration, lipid transfer to HDL, or size of HDL particles in normolipidemic nonobese women. (C) 2008 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd.All rights reserved.

The role of PKA and PKC epsilon pathways in prostaglandin E(2)-mediated hypernociception

Background and purpose: Protein kinase (PK) A and the epsilon isoform of PKC (PKC epsilon) are involved in the development of hypernociception (increased sensitivity to noxious or innocuous stimuli) in several animal models of acute and persistent inflammatory pain. The present study evaluated the contribution of PKA and PKC epsilon to the development of prostaglandin E(2) (PGE(2))-induced mechanical hypernociception. Experimental approach: Prostaglandin E(2)-induced mechanical hypernociception was assessed by constant pressure rat paw test. The activation of PKA or PKC epsilon was evaluated by radioactive enzymic assay in the dorsal root ganglia (DRG) of sensory neurons from the hind paws. Key results: Hypernociception induced by PGE(2) (100 ng) by intraplantar (i.pl.) injection, was reduced by i.pl. treatment with inhibitors of PKA [A-kinase-anchoring protein St-Ht31 inhibitor peptide (AKAPI)], PKC epsilon (PKC epsilon I) or adenylyl cyclase. PKA activity was essential in the early phase of the induction of hypernociception, whereas PKC activity was involved in the maintenance of the later phase of hypernociception. In the DRG (L4-L5), activity of PKA increased at 30 min after injection of PGE(2) but PKC activity increased only after 180 min. Moreover, i.pl. injection of the catalytic subunit of PKA induced hypernociception which was markedly reduced by pretreatment with an inhibitor of PKC epsilon, while the hypernociception induced by paw injection of PKC epsilon agonist was not affected by an inhibitor of PKA (AKAPI). Conclusions and implications: Taken together, these findings are consistent with the suggestion that PKA activates PKC epsilon, which is a novel mechanism of interaction between these kinases during the development of PGE(2)-induced mechanical hypernociception.

Decay chain differential equations: Solution through matrix algebra

A matricial method to solve the decay chain differential equations system is presented. The quantity of each nuclide in the chain at a time t may be evaluated by analytical expressions obtained in a simple way using recurrence relations. This method may be applied to problems of radioactive buildup and decay and can be easily implemented computationally. (C) 2009 Elsevier B.V. All rights reserved.

Phosphorus kinetics in calves experimentally submitted to a trickle infection with Cooperia punctata

Ten male Holstein calves (74.3 +/- 3.2 kg LW) were used for a trial with trickle infection with Cooperia punctata to evaluate phosphorus (P) kinetics. Five calves were inoculated with 10,000 L(3) stage larvae per week during 35 days, while the other group of five calves was kept as a control. On the 29th day each calf was intravenously injected with 29.6 MBq of a (32)p solution. Blood samples were taken at 24 h periods for 7 days, after which all calves were slaughtered and worms burdens. Faeces, urine and tissue samples were taken for analysis using isotopic dilution and modeling techniques. The number of eggs per gram of faeces (EPG)was 1920 +/- 168 on 28th day and the total number of worms burdens was 11,131 +/- 1500. Infected calves showed lower feed intake and live weight gain, as well as lower P intake, absorption and retention than control calves. The P flows between body compartments were lower for blood to gastrointestinal tract (TGI), TGI to blood, blood to soft tissues, bone balance and soft tissue balance in infected calves when compared to the control. The trickle infection of C punctata affected P metabolism due to the decrease in P retained and live weight due to fall in feed intake. (C) 2009 Elsevier B.V. All rights reserved.

LC-MS/MS quantitation of plasma progesterone in cattle

Quantitation of progesterone (P(4)) in biological fluids is often performed by radioimmunoassay (RIA), whereas liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has been used much less often. Due to its autoconfirmatory nature, LC-MS/MS greatly minimizes false positives and interference. Herein we report and compare with RIA an optimized LC-MS/MS method for rapid, efficient, and cost-effective quantitation of P(4) in plasma of cattle with no sample derivatization. The quantitation of plasma P(4) released from three nonbiodegradable, commercial, intravaginal P(4)-releasing devices (IPRD) over 192 h in six ovariectomized cows was compared in a pairwise study as a test case. Both techniques showed similar P(4) kinetics (P > 0.05) whereas results of P(4) quantitation by RIA were consistently higher compared with LC-MS/MS (P < 0.05) due to interference and matrix effects. The LC-MS/MS method was validated according to the recommended analytical standards and displayed P(4) limits of detection (LOD) and quantitation (LOQ) of 0.08 and a 0.25 ng/mL, respectively. The high selective LC-MS/MS method proposed herein for P(4) quantitation eliminates the risks associated with radioactive handling; it also requires no sample derivatization, which is a common requirement for LC-MS/MS quantitation of steroid hormones. Its application to multisteroid assays is also viable, and it is envisaged that it may provide a gold standard technique for hormone quantitation in animal reproductive science studies. (C) 2011 Elsevier Inc. All rights reserved.

Micro-tensile bond strength to bovine sclerotic dentine: Influence of surface treatment

Objective: The objective of this study was to evaluate the influence of the surface treatment and acid conditioning (AC) time of bovine sclerotic dentine on the micro-tensile bond strength (mu-TBS) to an etch and rinse adhesive system. Materials and method: Thirty-six bovine incisors were divided into six groups (n = 6): G1 sound dentine submitted to AC for 15 s; G2-G6 sclerotic dentine: G2-AC for 15 s; G3-AC for 30 s; G4-EDTA and AC for 15 s; G5-diamond bur and AC for 15 s; G6-diamond paste and AC for 15 s. An adhesive system was applied to the treated dentine surfaces followed by a hybrid composite inserted in increments and light cured. After 24 h storage in water at 37 degrees C, the specimens were perpendicularly cut with a low-speed diamond saw to obtain beams (0.8 mm x 0.8 mm cross-sectional dimensions) for mu-TBS testing. Data was compared by ANOVA followed by Tukey`s test (P <= 0.05). Results: The mean L-TBS was G1: 18.87 +/- 5.36 MPa; G2: 12.94 +/- 2.09 MPa; G3: 11.73 +/- 0.64 MPa; G4: 11.14 +/- 1.50 MPa; G5: 22.75 +/- 4.10 MPa; G6: 22.48 +/- 2.71 MPa. G1, G5 and G6 presented similar bond strengths significantly higher than those of all other groups. Conclusion: The surface treatment of sclerotic dentine significantly influenced the bond strength to an adhesive system. Mechanical treatment, either using a diamond bur or a diamond paste was able to improve bonding to bovine sclerotic dentine, reaching values similar to bonding to sound dentine. (C) 2008 Elsevier Ltd. All rights reserved.

Ethanol Wet-bonding Challenges Current Anti-degradation Strategy

The long-term effectiveness of chlorhexidine as a matrix metalloproteinase (MMP) inhibitor may be compromised when water is incompletely removed during dentin bonding. This study challenged this anti-bond degradation strategy by testing the null hypothesis that wet-bonding with water or ethanol has no effect on the effectiveness of chlorhexidine in preventing hybrid layer degradation over an 18-month period. Acid-etched dentin was bonded under pulpal pressure simulation with Scotchbond MP and Single Bond 2, with water wet-bonding or with a hydrophobic adhesive with ethanol wet-bonding, with or without pre-treatment with chlorhexidine diacetate (CHD). Resin-dentin beams were prepared for bond strength and TEM evaluation after 24 hrs and after aging in artificial saliva for 9 and 18 mos. Bonds made to ethanol-saturated dentin did not change over time with preservation of hybrid layer integrity. Bonds made to CHD pre-treated acid-etched dentin with commercial adhesives with water wet-bonding were preserved after 9 mos but not after 18 mos, with severe hybrid layer degradation. The results led to rejection of the null hypothesis and highlight the concept of biomimetic water replacement from the collagen intrafibrillar compartments as the ultimate goal in extending the longevity of resin-dentin bonds.

Solubility study of phytochemical cross-linking agents on dentin stiffness

Objectives: The effects of interactions between cross-linking proanthocyanidins (PA) in polar solvents and type-I collagen of demineralized dentin were investigated. Methods: Three PA-rich extracts, two from grape seed (GSEP and GSES) and one from cocoa (COE), were dissolved (water, ethanol:water and acetone:water) and analyzed for their ability to increase the modulus of elasticity of demineralized dentin. Sound dentin beams (0.5 mm x 1.7 mm x 7 mm) were fully demineralized and divided into 12 groups according to the type of cross-linking agent and solvents used. Specimens were immersed in the respective solutions and tested at baseline, 10, 30, 60, 120 and 240 min. Results: The elastic modulus (EM) of dentin was significantly increased by the PA treatment regardless of time (p < 0.05 for all times). The extracts showed different solubility in different solvents. GSEP showed the highest increase in EM when diluted in distilled water and acetone at all exposure times. Both GSEs showed superior results when diluted in distilled water and after 4 h of treatment, while COE produced strongest enhancement when dissolved in ethanol:water. Conclusions: The results indicates that herbal extraction process and other pharmacognostic parameters have an important influence on extract solubility as well as constitution and, consequently, on the PA-dentin matrix interaction. (C) 2010 Elsevier Ltd. All rights reserved.

Six-month evaluation of adhesives interface created by a hydrophobic adhesive to acid-etched ethanol-wet bonded dentine with simplified dehydration protocols

Objectives: To evaluate the efficacy of simplified dehydration protocols, in the absence of tubular occlusion, on bond strength and interfacial nanoleakage of a hydrophobic experimental adhesive blend to acid-etched, ethanol-dehydrated dentine immediately and after 6 months. Methods: Molars were randomly assigned to 6 treatment groups (n = 5). Under pulpal pressure simulation, dentine crowns were acid-etched with 35% H(3)PO(4) and rinsed with water. Adper Scotchbond Multi-Purpose was used for the control group. The remaining groups had their dentine surface dehydrated with ethanol solutions: group 1 = 50%, 70%, 80%, 95% and 3 x 100%, 30 s for each application; group 2 the same ethanol sequence with 15 s for each solution; groups 3, 4 and 5 used 100% ethanol only, applied in seven, three or one 30 s step, respectively. After dehydration, a primer (50% BisGMA + TEGDMA, 50% ethanol) was used, followed by the neat comonomer adhesive application. Resin composite build-ups were then prepared using an incremental technique. Specimens were stored for 24 h, sectioned into beams and stressed to failure after 24 h or after 6 months of artificial ageing. Interfacial silver leakage evaluation was performed for both storage periods (n = 5 per subgroup). Results: Group 1 showed higher bond strengths at 24 h or after 6 months of ageing (45.6 +/- 5.9(a)/43.1 +/- 3.2(a) MPa) and lower silver impregnation. Bond strength results were statistically similar to control group (41.2 +/- 3.3(ab)/38.3 +/- 4.0(ab) MPa), group 2 (40.0 +/- 3.1(ab)/38.6 +/- 3.2(ab) MPa), and group 3 at 24 h (35.5 +/- 4.3(ab) MPa). Groups 4 (34.6 +/- 5.7(bc)/25.9 +/- 4.1(c) MPa) and 5 (24.7 +/- 4.9(c)/18.2 +/- 4.2(c) MPa) resulted in lower bond strengths, extensive interfacial nanoleakage and more prominent reductions (up to 25%) in bond strengths after 6 months of ageing. Conclusions: Simplified dehydration protocols using one or three 100% ethanol applications should be avoided for the ethanol-wet bonding technique in the absence of tubular occlusion, as they showed decreased bond strength, more severe nanoleakage and reduced bond stability over time. (C) 2009 Elsevier Ltd. All rights reserved.

A critical view on biaxial and short-beam uniaxial flexural strength tests applied to resin composites using Weibull, fractographic and finite element analyses

Objective. To evaluate the biaxial and short-beam uniaxial strength tests applied to resin composites based upon their Weibull parameters, fractographic features and stress distribution. Methods. Disk- (15 mm x 1 mm) and beam-shaped specimens (10 mm x 2 mm x 1 mm) of three commercial composites (Concept/Vigodent, CA; Heliomolar/Ivoclar-Vivadent, HE; Z250/3M ESPE, FZ) were prepared. After 48h dry storage at 37 degrees C, disks and beams were submitted to piston-on-three-balls (BI) and three-point bending (UNI) tests, respectively. Data were analyzed by Weibull statistics. Fractured surfaces were observed under stereomicroscope and scanning electron microscope. Maximum principal stress (sigma(1)) distribution was determined by finite element analysis (FEA). Maximum sigma(1-BI) and sigma(1-UNI) were compared to FZ strengths calculated by applying the average failure loads to the analytical equations (sigma(a-BI) and sigma(a-UNI)). Results. For BI, characteristic strengths were: 169.9a (FZ), 122.4b (CA) and 104.8c (HE), and for UNI were: 160.3a (FZ), 98.2b (CA) and 91.6b (HE). Weibull moduli ( m) were similar within the same test. CA and HE presented statistically higher m for BI. Surface pores ( BI) and edge flaws ( UNI) were the most frequent fracture origins. sigma(1-BI) was 14% lower than sigma(a-BI.) sigma(1-UNI) was 43% higher than sigma(a-UNI). Significance. Compared to the short-beam uniaxial test, the biaxial test detected more differences among composites and displayed less data scattering for two of the tested materials. Also, biaxial strength was closer to the material`s strength estimated by FEA. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Bis-GMA co-polymerizations: Influence on conversion, flexural properties, fracture toughness and susceptibility to ethanol degradation of experimental composites

Objectives. The aim of this study was to evaluate the influence of monomer content on fracture toughness (K(Ic)) before and after ethanol solution storage, flexural properties and degree of conversion (DC) of bisphenol A glycidyl methacrylate (Bis-GMA) co-polymers. Methods. Five formulations were tested, containing Bis-GMA (B) combined with TEGDMA (T), UDMA (U) or Bis-EMA (E), as follows (in mol%): 30B:70T; 30B:35T:35U; 30B:70U; 30B:35T:35E; 30B:70E. Bimodal filler was introduced at 80 wt%. Single-edge notched beams for fracture toughness (FT, 25 mm x 5 mm x 2.5 mm, a/w = 0.5, n = 20) and 10 mm x 2 mm x 1 mm beams for flexural strength (FS) and modulus (FM) determination (10 mm x 2 mm x 1 mm, n = 10) were built and then stored in distilled water for 24 h at 37 degrees C. All FS/FM beams and half of the FT specimens were immediately submitted to three-point bending test. The remaining FT specimens were stored in a 75%ethanol/25%water (v/v) solution for 3 months prior to testing. DC was determined with FT-Raman spectroscopy in fragments of both FT and FS/FM specimens at 24 h. Data were submitted to one-way ANOVA/Tukey test (alpha = 5%). Results. The 30B:70T composite presented the highest K(Ic) value (in MPa m(1/2)) at 24 h (1.3 +/- 0.4), statistically similar to 30B:35T:35U and 30B:70U, while 30B:70E presented the lowest value (0.5 +/- 0.1). After ethanol storage, reductions in K(Ic) ranged from 33 to 72%. The 30B:70E material presented the lowest reduction in FT and 30B:70U, the highest. DC was similar among groups (69-73%), except for 30B:70U (52 +/- 4%, p < 0.001). 30B:70U and 30B:35T:35U presented the highest FS (125 +/- 21 and 122 +/- 14 MPa, respectively), statistically different from 30B:70T or 30B:70E (92 +/- 20 and 94 +/- 16 MPa, respectively). Composites containing UDMA or Bis-EMA associated with Bis-GMA presented similar FM, statistically lower than 30B:35T:35U. Significance. Composites formulated with Bis-GMA:TEGDMA:UDMA presented the best compromise between conversion and mechanical properties. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Durability of Enamel Bonding Using One-step Self-etch Systems on Ground and Unground Enamel

Objective: To examine the morphological, early and long-term microtensile bond strengths (mu TBS) of one-step self-etch systems to unground and ground enamel. Materials and Methods: Resin composite (Filtek Z250) buildups were bonded to the buccal and lingual enamel surfaces (unground, bur-cut or SiC-roughened enamel) of third molars after adhesive application using the following adhesives: Clearfil S(3) Bond (CS3); Adper Prompt L-Pop (ADP); iBond (iB) and, as the control, Clearfil SE Bond (CSE). Six tooth halves were assigned for each condition. After storage in water (24 hours/37 degrees C), the bonded specimens were sectioned into beams (0.8 mm(2)) and subjected to pTBS (0.5 mm/min) either immediately (IM) or after six (6M) or 12 months (12M) of water storage. The data were analyzed by three-way repeated measures ANOVA and Tukey`s test (alpha=0.05). Surface conditioning was observed under scanning electron microscopy (SEM). Results: The mu TBS in the Si-C paper and diamond bur groups were similar and higher than the unground group. No significant difference was observed among the different storage periods, except for CS3, which showed an increase in the pTBS after 12M. The etching pattern was more retentive on ground enamel. Conclusions: One-step self-etch adhesives showed higher bond strengths on ground enamel and no reductions in resin-enamel bonds were observed after 12M of water storage.

Durability of enamel bonding using two-step self-etch systems on ground and unground enamel

This study examined the early and long-term microtensile bond strengths (mu TBS) and interfacial enamel gap formation (IGW) of two-step selfetch systems to unground and ground enamel. Resin composite (Filtek Z250) buildups were bonded to proximal enamel surfaces (unground, bur-cut or SiC-treated enamel) of third molars after the application of four self-etch adhesives: a mild (Clearfil SE Bond [SE]), two moderate (Optibond Solo Plus Self-Etch Primer [SO] and AdheSE [AD]) and a strong adhesive (Tyrian Self Priming Etchant + One Step Plus [TY]) and two etch-and-rinse adhesive systems (Single Bond [SB] and Scotchbond Multi-Purpose Plus [SBMP]). Ten tooth halves were assigned for each adhesive. After storage in water (24 hours/37 degrees C), the bonded specimens were sectioned into beams (0.9 mm(2)) and subjected to mu TBS (0.5 mm/minute) or interfacial gap width measurement (stereomicroscope at 400x) either immediately (IM) or after 12 months (12M) of water storage. The data were analyzed by three-way repeated measures ANOVA and Tukey`s test (alpha=0.05). No gap formation was observed in any experimental condition. The mu TBS in the Si-C paper and diamond bur groups were similar and greater than the unground group only for the moderate self-etch systems (SO and AD). No reductions in bond strength values were observed after 12 months of water storage, regardless of the adhesive evaluated.

Differential bonds degradation of two resin-modified glass-ionomer cements in primary and permanent teeth

Objectives: To evaluate the effect of chemical degradation on bond strength of resin-modified glass-ionomer cements bonded to primary and permanent dentin. Methods: Class I cavities of permanent and primary extracted human molars were restored with two resin-modified glass-ionomer cements: Fuji 11 LC and Vitremer, and stored in water for 24 h. Half samples were immersed in 10% NaOCl aqueous solution for 5 h. Teeth were sectioned into beams and tested for microtensile bond strengths. Results were analyzed with multiple ANOVA and Tukey`s tests (p < 0.05). Analysis of debonded surfaces was performed by SEM. Results: 24 h bond strengths for Vitremer and Fuji 11 LC were similar. For Fuji 11, bond strength values were higher for primary than for permanent dentin. Vitremer bond strength was similar for both. Chemical degradation did not affect Fuji I] LC bond strength to dentin. However, decreases in bond strength were found for Vitremer groups after NaOCl immersion. Signs of glass ionomer-dentin interaction were evident by SEM analysis for Fuji 11 LC specimens. Conclusions: Vitremer and Fuji II presented similar bond strength at 24. Vitremer dentin bonds were prone to chemical degradation. Fuji II LC-dentin bonds showed typical features of glass-ionomer dentin interaction at the bonded interfaces, and were resistant to in vitro degradation. (C) 2009 Elsevier Ltd. All rights reserved.