Long-lasting memory of jasmonic acid-dependent immunity requires DNA demethylation and ARGONAUTE1.

Stress can have long-lasting impacts on plants. Here we report the long-term effects of the stress hormone jasmonic acid (JA) on the defence phenotype, transcriptome and DNA methylome of Arabidopsis. Three weeks after transient JA signalling, 5-week-old plants retained induced resistance (IR) against herbivory but showed increased susceptibility to pathogens. Transcriptome analysis revealed long-term priming and/or upregulation of JA-dependent defence genes but repression of ethylene- and salicylic acid-dependent genes. Long-term JA-IR was associated with shifts in glucosinolate composition and required MYC2/3/4 transcription factors, RNA-directed DNA methylation, the DNA demethylase ROS1 and the small RNA (sRNA)-binding protein AGO1. Although methylome analysis did not reveal consistent changes in DNA methylation near MYC2/3/4-controlled genes, JA-treated plants were specifically enriched with hypomethylated ATREP2 transposable elements (TEs). Epigenomic characterization of mutants and transgenic lines revealed that ATREP2 TEs are regulated by RdDM and ROS1 and produce 21 nt sRNAs that bind to nuclear AGO1. Since ATREP2 TEs are enriched with sequences from IR-related defence genes, our results suggest that AGO1-associated sRNAs from hypomethylated ATREP2 TEs trans-regulate long-lasting memory of JA-dependent immunity.

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.

Effect of the C-factor and dentin preparation method in the bond strength of a mild self-etch adhesive.

This study evaluated the effect of the C-factor and dentin preparation method (DPM) in the bond strength (BS) of a mild self-etch adhesive; the study also observed the SEM superficial aspects of the corresponding smear layer. For purposes of this study, 25 molars (n=5) were used in a bond strength test. The molars were divided into two parts (buccal and lingual): one part received a Class V cavity (C-factor=3) and the other received a flat surface (C-factor=0) with the same bur type (coarse diamond or carbide bur and fine diamond or carbide bur), both within the same dentin depth. Five teeth were prepared with wet 60-grit and 600-grit SiC papers. After restoration with Clearfil SE Bond, microtensile beans (0.8 mm2) were prepared and tested after 24 hours in a universal testing machine (0.5 mm/minute). An additional two teeth for each DPM were prepared for SEM evaluation of the smear layer superficial aspects. The BS values were submitted to one-way ANOVA, considering only the DPM (flat surfaces) and two-way ANOVA (C-Factor x DPM, considering only burs) with p=0.05. Although the DPM in the flat surfaces was not significant, the standard deviations of carbide bur-prepared specimens were markedly lower. The BS was significantly lower in cavities. The fine carbide bur presented the most favorable smear layer aspect. It was concluded that different dentin preparation methods could not prevent the adverse effect in bond strength of a high C-factor. A coarse cut carbide bur should be avoided prior to a mild self-etch adhesive, because it adversely affected bond strength. In contrast, a fine cut carbide bur provided the best combination: high bond strength with low variability, which suggests a more reliable bond strength performance.

Cell type-specific and sexually dimorphic expression of transcription factor AP-2 in the adult mouse brain.

Expression of transcription factor AP-2 family genes in adult mouse brain regions was examined at RNA and protein levels and in tissue sections. AP-2 family RNA transcripts, nuclear AP-2 DNA binding activity, and AP-2 immunoreactivity were greatest in hindbrain and midbrain regions. Cells expressing AP-2 were predominantly differentiated neurons and were abundant in the solitary tract nucleus, hypoglossal nucleus, locus coeruleus, cerebellar molecular layer, superior colliculus, mitral cell layers of the main and accessory olfactory bulbs, and in some divisions of the bed nucleus of the stria terminalis. Sexually dimorphic expression of AP-2 was seen in the bed nucleus of the stria terminalis, a forebrain region required for regulation of gender-specific reproductive and social behaviors. In males, AP-2 expressing neurons were present in supracapsular, lateral ventral, and medial ventral divisions of the bed nucleus of the stria terminalis. In contrast, females had AP-2 expressing neurons in the lateral ventral division, but not the supracapsular division, and AP-2 expression in medial ventral division neurons oscillated during the estrus cycle. With the exception of the bed nucleus of the stria terminalis, forebrain regions generally lacked cells with high levels of AP-2. However, a small population of cells co-expressing low levels of AP-2 and Notch1 was sparsely distributed in the cerebral cortex and hippocampal dentate gyrus subgranular zone. Based on their variable levels of NeuN, a marker for differentiated neurons, these cells may include nascent neurons. A subset of cerebellar Purkinje cells also co-expressed low levels of AP-2 and Notch1. Together, the adult brain regions with AP-2 expressing neurons are notable for their importance in pathways that integrate sensory and neuroendocrine information for regulation of reproductive, social, and feeding behaviors. Our data suggest that AP-2 transcription factors contribute at multiple levels to adult brain function including regulation of gender-specific behavior.

Cerebral, myocardial and cutaneous ischemic necrosis associated with calcific emboli from aortic and mitral valve calcification in a patient with end-stage renal disease.

We report the case of a 57-year-old diabetic male with chronic renal failure who developed secondary hyperparathyroidism and calcification of mitral and aortic valves and interatrial septum. Multiple ischemic lesions developed in the skin of hands, feet and penis, and in the brain, and these were presumed to be due to septic emboli from cardiac valvular infective endocarditis. Multiple blood cultures were negative, however, and despite antibiotic therapy the patient expired. Autopsy (limited to trunk) demonstrated multiple calcific emboli in the heart and spleen, apparently derived from the prominent calcific deformities in the aortic and mitral valves. These were associated with acute and organizing myocardial infarcts and acute splenic infarcts, suggesting that the multiple ischemic lesions in the brain were also due to calcific emboli. A possible contributory component of infective endocarditis, however, was indicated by postmortem cultures of aortic and mitral valves positive for Enterococcus faecium. Calcific embolism is a rarely recognized but potentially lethal complication of end-stage renal disease, and the clinical diagnosis and the preventive therapeutic options for the control of the product of calcium and phosphate and/or parathyroidectomy should be considered.

In vitro and in vivo corrosion evaluation of nickel-chromium- and copper-aluminum-based alloys.

STATEMENT OF PROBLEM: The low resistance to corrosion is the major problem related to the use of copper-aluminum alloys. PURPOSE: This in vitro and in vivo study evaluated the corrosion of 2 copper-aluminum alloys (Cu-Al and Cu-Al-Zn) compared with a nickel-chromium alloy. MATERIAL AND METHODS: For the in vitro test, specimens were immersed in the following 3 corrosion solutions: artificial saliva, 0.9% sodium chloride, and 1.0% sodium sulfide. For the in vivo test, specimens were embedded in complete dentures, so that one surface was left exposed. The 3 testing sites were (1) close to the oral mucosa (partial self-cleaning site), (2) surface exposed to the oral cavity (self-cleaning site), and (3) specimen bottom surface exposed to the saliva by means of a tunnel-shaped perforation (non-self-cleaning site). RESULTS: Almost no corrosion occurred with the nickel-chromium alloy, for either the in vitro or in vivo test. On the other hand, the 2 copper-aluminum-based alloys exhibited high corrosion in the sulfide solution. These same alloys also underwent high corrosion in non-self-cleaning sites for the in vivo test, although minimal attack was observed in self-cleaning sites. CONCLUSION: The nickel-chromium alloy presented high resistance to corrosion. Both copper-aluminum alloys showed considerable corrosion in the sulfide solution and clinically in the non-self-cleaning site. However, in self-cleaning sites these 2 alloys did not show substantial corrosion.

Influence of different dentinal substrates on the tensile bond strength of three adhesive systems.

PURPOSE: To evaluate the influence of the method and duration of storage for different types of teeth prior to their use in dentin bonding tests with three adhesive systems. MATERIALS AND METHODS: Recently extracted sound human molars, bovine incisors, and human caries-free molars obtained from exhumed bones 5 years postmortem were used. The latter group of teeth was kept dry for 6 months, and then rehydrated in distilled water over a period of 30 days. The adhesive systems used were Prime&Bond 2.1. Single Bond, and Etch&Prime 3.0. Human teeth were embedded longitudinally in PVC cylinders; bovine incisors were embedded leaving the buccal surface exposed. Flat dentin surfaces were cut with a diamond disk and ground with up to 600-grit SiC paper. Adhesives were applied following manufacturers' instructions. A silicone mold with a cone-shaped perforation (4.5 mm high and 2 mm diameter at the smallest) was fixed on the dentin surface and filled with TPH composite resin. The specimens were stored in distilled water for two weeks before testing. RESULTS: ANOVA did not detect statistical differences either in the main factors (substrate and adhesive system) or in their interaction (p > 0.05). Tensile bond strength averages ranged from 11.6 to 14.2 MPa. The dentinal substrates showed similar performances, regardless of the adhesives tested. CONCLUSION: The differences among the three dentin substrates do not appear to be critical for the tensile bond strength test for the three adhesive systems. The adhesive systems presented similar bond strengths.

The medial gastrocnemius muscle flap in the treatment of wound complications following total knee arthroplasty.

There is greater potential for wound healing complication in rheumatoids, diabetics, and other patients with peripheral vascular disease. Local wound care in areas of avascularity and skin necrosis has poor results, especially if an ulcer is greater than 2 cm in diameter. Gastrocnemius muscle flap coverage of persistent wounds and areas of skin necrosis following total knee arthroplasty should be considered early in the course of such a complication.

[Influence of bacterial plaque disclosing agents on patient oral hygiene motivation under direct supervision and direction]. / Estudo clínico da influênçia dos evidenciadores de placa bacteriana na motivação de pacientes à higiene bucal sob supervisão e orientação direta.

Research was carried out with the objective of studying the clinical influence of dental plaque disclosing agents as motivators for patients oral hygiene. Methylene blue, basic fuchsin, Bismark brown, malachite green, and gentian violet were used for dental plaque disclosure. Five groups were evaluated, 12 patients each, besides a control group of 12 patients. The experimental period analysed statistically was of approximately 7 weeks. The statistical analysis of the results proved not to have significant differences among the 6 groups analysed.

[Influence of escape channels (vents) in reproduction of occlusal contacts and external surface of complete cast metal crowns]. / Influência nos condutos para escape de ar (ventings) na reprodução dos contactos oclusais e superficie externa de coroas totais metálicas fundidas.

The purpose of this investigation was to verify the influence of ventings on the reproduction of interocclusal contacts from the wax pattern to the cast crown and also to note the influence on surface quality. Comparatively were performed tests with no venting, with one joined on the outside of the full crown wax pattern and two ventings joined on the sprues (Fig. 2). The castings were obtained with a nickel-chrome alloy and investing was performed with phosphate bonded investment. From the results it was possible to conclude: casting without venting presented higher frequency of no reproduction of interocclusal contact points; when using one venting, joined on the outside of the crown wax pattern, the reproduction of the interocclusal contacts was 100%, the venting did not lead to high improvement on the surface quality.

[Consistency of zinc oxide-eugenol impression materials]. / Consistência das pastas zincoeugenólicas para moldagem.

The purpose of this work was investigate the consistency of three zinc oxide-eugenol impression pastes, considering its flow. Flow tests were performed based on the AMERICAN DENTAL ASSOCIATION-Specification no 16. Setting time was based at that one when should be applied the load to get considered disc diameter; the values were obtained graphically. Considering the results it was possible to conclude: a) the first two materials (Equalizing and Horus) present high initial flow, which however drops down earlier on the second one; b) both materials may be used with non compressive impression technic but the second one has shorter working time; c) the third material (Lysanda) as it presents lower flow and faster setting time, may be used with compressive impression technic.

[Soldering of a low gold content alloy (46%)]. / Esutdo da soldagem de uma liga com baixo conteúdo de ouro (46%).

This is the third part of a research about a low gold content alloy (Au 46%, Pd 4%, Ag 40%, Cu and Zn), involving the study of soldered joints. Transverse test was used to evaluate mechanical resistance of bars joined by soldering. Comparativily were considered the following "soldering" condution: entire bars without investing and without soldering; entire bars with investing and without soldering but simulating thermal cycle and quenched in water after one and five minutes; with investing, soldering and quenched in water after one and five minutes. Of the "soldered" alloy were obtained also Brinell and Vickers hardness numbers. Corrosion resistance test was performed for six month at vapors of acetic acid solution, saturated with hydrogen sulfide. From the results it was possible to conclude: the soldered joints of the alloy reach good corrosion resistance; the soldered joints do not become brittle; thermal cycling as elapsed from soldering procedure and water quenched after five minutes increases the strength of the alloy and the soldered joints.

[Mechanical, physical and corrosive properties, and relative cost of a low gold content alloy (46%)]. / Propriedades mecânicas, físicas e de corrosão, e custo relativo de uma liga com baixo conteúdo de ouro (46%).

The research presents some properties of a low gold content (46%) alloy. Mechanical properties were performed with specimens submitted to several treatment; as cast; hardened at 400 degrees C/15 min; softened at 700 degrees C/10 min; and hardened after softening. Melting temperature was considered when the alloy become a liquid sphere. Casting shrinkage determination was based on the method presented by EARNSHAW. Density was obtained by the weight of polished specimens in and out of water. Corrosion was tested at vapors of acetic acid solution, saturated with hydrogen sulfide, for a period of six months. Cost was computed on base of materials cost and density of alloy. The results showed: tensile strength and proportional limit are very high, specially when hardened and the alloy may be used for large bridges; elongation is low when alloy was heat hardened, but is good when in the as cast condition; the alloy may be handled with conventional materials and equipment; corrosion resistance is excellent; final cost is a little higher than half that of conventional gold alloy.

["In vitro" analysis of the dentin permeability of the apical third of the root as a function of changes in auxiliary chemicals used in instrumentation]. / Análise "in vitro" da permeabilidade dentinária radicular do terço apical, tendo como fonte de variação a substância quimica auxiliar da instrumentação.

We analyzed the possible percentage variations of dentinal penetration of the methylene blue solution in the apical third, in human teeth pulled out, after it's preparation, utilizing files type K-Flex, and five auxiliary chemical substances. Results have shown that there is a significant difference among the percentage of the dye penetration and among the auxiliary chemical substances used for the chemical-mechanic preparation. We can also prove true that, for apical region, the Endo PTC was the one that showed the greatest percentage of penetration.