In vivo study of the biocompatibility of a novel compressed collagen hydrogel scaffold for artificial corneas

The experiments were designed to evaluate the biocompatibility of a plastically compressed collagen scaffold (PCCS). The ultrastructure of the PCCS was observed via scanning electron microscopy. Twenty New Zealand white rabbits were randomly divided into experimental and control groups that received corneal pocket transplantation with PCCS and an amniotic membrane, respectively. And the contralateral eye of the implanted rabbit served as the normal group. On the 1st, 7th, 14th, 21st, 30th, 60th, 90th, and 120th postoperative day, the eyes were observed via a slit lamp. On the 120th postoperative day, the rabbit eyes were enucleated to examine the tissue compatibility of the implanted stroma. The PCCS was white and translucent. The scanning electron microscopy results showed that fibers within the PCCS were densely packed and evenly arranged. No edema, inflammation, or neovascularization was observed on ocular surface under a slit lamp and few lymphocytes were observed in the stroma of rabbit cornea after histological study. In conclusion, the PCCS has extremely high biocompatibility and is a promising corneal scaffold for an artificial cornea. (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.

Poor survival on an artificial diet of two genotypes of the aphid Myzus persicae: a fitness cost of insecticide resistance?

A fully susceptible genotype (4106A) of Myzus persicae survived the longest on an artificial diet and, in several of the eight replicates, monitoring was terminated when the culture was still thriving. A genotype with elevated carboxylesterase FE4 at the R3 level (800F) had a mean survival of only 98.13 days, whereas 794J, which combines R3 E4 carboxylesterase with target-site resistance (knockdown resistance), survived for the even shorter mean time of 84.38 days. The poorer survival of the two genotypes with extremely elevated carboxylesterase-resistance was not the result of a reluctance to transfer to new diet at each diet change. Although available for only two replicates, a revertant clone of 794J (794Jrev), which has the same genotype as 794J but the amplified E4 genes are not expressed leading to a fully susceptible phenotype, did not appear to survive any better than this clone. This suggests that the poor survival on an artificial diet of the extreme-carboxylesterase genotypes is not the result of the cost of over-producing the enzyme. The frequency of insecticide-resistant genotypes is low in the population until insecticide is applied, indicating that they have reduced fitness, although this does not necessarily reflect a direct cost of expressing the resistance mechanism.

The effect of artificial diet on the production of alarm pheromone by Myzus persicae.

The cornicle secretion of Myzus persicae reared on artificial diet only elicits an alarm response in plant-reared conspecifics after the young aphids have been transferred to plants for 7days. Acetate in the form of 0.32% sodium acetate has been added to the diet as an early step in synthesis of the alarm pheromone, (E)-β-farnesene (EBF). The cornicle secretion of diet-reared aphids then elicits an alarm response. However, there is no difference in internal EBF concentration between plant- and diet-reared aphids. Puncturing aphids, either plant- or diet-reared, with a pin shows that both can elicit an alarm response, whereas it is reduced by half with diet-reared individuals. Although there is no significant difference in the concentration of EBF produced, the total amount in diet-reared aphids is increased by acetate in the diet to a level similar to that in plant-reared individuals: the size of aphids reared on an acetate-supplemented diet is increased and comparable with the size of those that are plant-reared. Bioassays with a range of EBF concentrations show a high threshold for the alarm response. It is concluded that the different size of aphids reared on plants and standard diet results in them secreting, respectively, above and below the response threshold.

Senna alata leaves are a good source of propelargonidins

Proanthocyanidins (PA) in Senna alata leaves were investigated by thiolysis with benzyl mercaptan, LC–MS and NMR and consisted of almost pure propelargonidins with <6% procyanidins, had B-type linkages and a mean degree of polymerisation of three. Epiafzelechin was the major flavan-3-ol subunit (>94%) and epicatechin a minor constituent (6.4%) in residual PA and mainly detected as an extension unit.

New furoquinoline alkaloid and flavanone glycoside derivatives from the leaves of Oricia suaveolens and Oricia renieri (Rutaceae)

Fractionation of the methanol extract of the leaves of Oricia renieri and Oricia suaveolens (Rutaceae) led to the isolation of 13 compounds including the hitherto unknown furoquinoline alkaloid named 6,7-methylenedioxy-5-hydroxy-8-methoxydictamnine (1) and a flavanone glycoside named 5-hydroxy-40-methoxy-7-O-[a-Lrhamnopyranosyl(1000→500)-b-D-apiofuranosyl]-flavanoside (2), together with 11 known compounds (3–13). The structures of the compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral data and comparison. All compounds isolated were examined for their activity against human carcinoma cell lines. The alkaloids 1, 5, 12, 13 and the phenolic 2, 8, 11 tested compounds exhibited non-selective moderate cytotoxic activity with IC50 8.7–15.9mM whereas compounds 3, 4, 6, 7, 9 and 10 showed low activity.

Heathland restoration on former agricultural land: effects of artificial acidification on the availability and uptake of toxic metal cations

Lowland heath is an internationally important habitat type that has greatly declined in abundance throughout Western Europe. In recent years this has led to a growing interest in the restoration of heathland on agricultural land. This generally requires the use of chemical treatments to return soil chemical conditions to those appropriate for the support of heathland ecosystems. However, the potential for negative impacts on the environment due to the potential of these treatments to increase the availability of trace metals via raised soil acidity requires investigation. A large-scale field study investigated the effect of two chemical treatments used in heathland restoration, elemental sulphur and ferrous sulphate, on soil acidity and whether it is possible to predict the effect of the treatments on availability of two potentially toxic cations (Al and Cd) in the soil along with their subsequent accumulation in the shoots of the grass Agrostis capillaris. Results showed that both treatments decreased soil pH, but that only elemental sulphur produced a pH similar to heathland soil. The availability of Al, measured by extraction with 1 M ammonium nitrate, could not be predicted by soil pH, depth in the soil and total Al concentration in the soil. By contrast, availability of Cd could be predicted from these three variables. Concentrations of both Al and Cd in the shoots of A. capillaris showed no significant relationship with the extractable concentration in the soil. Results are discussed in light of the possible environmental impacts of the chemical restoration techniques.

Proanthocyanidins from Averrhoa bilimbi fruits and leaves

Proanthocyanidins from Averrhoa bilimbi fruits and leaves were analysed by thiolysis with benzyl mercaptan and high performance liquid chromatography–mass spectrometry and consisted of pure B-type procyanidins. These tannins consisted of almost pure homopolymers, with epicatechin accounting for most of the monomeric subunits in fruits (97%) and leaves (99%). Leaves contained more procyanidins (4.5 vs 2.2 g/100 g dry weight) with a higher mean degree of polymerisation (9 vs 6) than fruits. This study thus contributes information on the proanthocyanidins of a traditional food that can make an important contribution to the intake of compounds with antioxidant and health benefits. The fruits are prized for culinary purposes and the leaves are used in traditional medicine.

Rapid, automated detection of stem canker symptoms in woody perennials using artificial neural network analysis

Background Pseudomonas syringae can cause stem necrosis and canker in a wide range of woody species including cherry, plum, peach, horse chestnut and ash. The detection and quantification of lesion progression over time in woody tissues is a key trait for breeders to select upon for resistance. Results In this study a general, rapid and reliable approach to lesion quantification using image recognition and an artificial neural network model was developed. This was applied to screen both the virulence of a range of P. syringae pathovars and the resistance of a set of cherry and plum accessions to bacterial canker. The method developed was more objective than scoring by eye and allowed the detection of putatively resistant plant material for further study. Conclusions Automated image analysis will facilitate rapid screening of material for resistance to bacterial and other phytopathogens, allowing more efficient selection and quantification of resistance responses.

COLOR STABILITY OF DENTAL CERAMICS SUBMITTED TO ARTIFICIAL ACCELERATED AGING AFTER REPEATED FIRINGS

Statement of problem. Color stability is an important factor to ensure the long-term clinical success of ceramic restorations. There is a lack of information on how color is affected by fabrication procedures, such as the number of firings. Purpose. The purpose of this study was to evaluate the effects that the number of firings and type of substrate have on the color stability of dental ceramic submitted to artificial accelerated aging. Material and methods. Sixty specimens were fabricated: 30 metal ceramic (Verabond II + IPS d.SIGN) and 30 all-ceramic (IPS d.SIGN). Specimens were divided into 3 groups (n=10), and submitted to 2, 3, or 4 firings (+/- 900 degrees C), respectively, according to the manufacturer`s instructions. Color readings were obtained with a spectro photometer before and after artificial accelerated aging, and L*, a*, and b* coordinates and total color variation (Delta E) were analyzed (2-way ANOVA, Bonferroni, (alpha=05). Results. For metal ceramic specimens, differences for the L* coordinates were significant (P<.05) only for the group submitted to 3 firings. With respect to the all-ceramic specimens, smaller L* coordinates were obtained for greater a* and b* coordinates, indicating that the greater the number of firings, the darker and more reddish/yellowish the specimen. All Delta E values, for all groups, were below 1.0. All-ceramic specimens submitted to 3 and 4 firings presented Delta E means differing statistically (P<.05) from those of the metal ceramic group. Conclusions. The type of substrate and number of firings affected the color stability of the ceramic material tested. Artificial accelerated aging did not produce perceptible color stability changes (Delta E<1.0). (J Prosthet Dent 2009-101:13-18)

Corrosion behavior of pure titanium in artificial saliva solution

The biocompatibility of commercially pure (cp) titanium stems from its chemical stability within an organism, due to a fine film of impermeable titanium oxide covering the metal surface, which guarantees its resistance to corrosion. Despite its biocompatible characteristic, this material does not promote the formation of a hydroxyapatite layer, therefore, many research groups have sought to alter the material`s surface, introducing modifications that might influence corrosion resistance. The electrochemical behavior of cp Ti, with hydroxyapatite coating and without hydroxyapatite coating, commonly used in implant materials, was investigated using an artificial saliva solution at 25 degrees C and pH=7.4. In the conditions of the study it was observed that the hydroxyapatite layer influences the properties of corrosion resistance. This study of the behavior of cp Ti with and without hydroxyapatite coating, in naturally aerated artificial saliva solution at 25 degrees C, was based on open circuit potential measurements and potentiodynamic polarization curves. At approximately 1x10(-6) A/cm(2) the potential for cp Ti with and without hydroxyapatite coating begins to increase at a faster rate, but at -74mV (SCE) for coated cp Ti and at 180mV (SCE) for uncoated cp Ti the increase in potential begins to slow. This behavior, characterized by a partial stabilization of current density, indicates that in those potential ranges a protective passive film is formed.

Extracts from pitanga (Eugenia uniflora L.) leaves: Influence of extraction process on antioxidant properties and yield of phenolic compounds

Different extraction processes were employed to extract the polyphenolic compounds from pitanga (Eugenia uniflora L) leaves: a one-step process using water, ethanol or supercritical CO(2) as solvents, and a two-step process using supercritical CO(2) followed by either water or ethanol. The total polyphenolic compounds, total flavonoids and antioxidant activity were determined in all the extracts obtained. The process performance was evaluated with respect to three variables: global extraction yield, concentration and yield of both polyphenols and flavonoids in the extracts. For the one-step extraction, the results showed that the extraction yield increased with solvent polarity. For the two-step process, the results suggested that water was more efficient in extracting the phenolic compounds from E. uniflora when the matrix was previously extracted with scCO(2). With respect to the antioxidant activity, the ethanolic extracts obtained from both processes, using either the DPPH radical scavenging method or the beta-carotene bleaching method, presented high antioxidant activities. (C) 2010 Elsevier B.V. All rights reserved.

COMPOSITION OF SUPERCRITICAL CARBON DIOXIDE EXTRACTS OF PITANGA (EUGENIA UNIFLORA L.) LEAVES

The leaves of the Pitanga bush (Eugenia uniflora L.) are considered to be effective against many diseases. Extracts from Pitanga leaves have been found to show pronounced anti-inflammatory action and to have antimicrobial and antifungal activities, among other properties. In this work, extracts from Pitanga leaves were obtained by hydrodistillation and by extraction with supercritical carbon dioxide (SC-CO(2)) at three conditions of temperature and pressure. In the SC-CO(2) extractions also were collected the components that are lost with the CO(2) in the exit of the system using Porapak-Q polymer trap. All extracts were analyzed by gas chromatography-mass spectrometry (GC-MS). Thirty-nine compounds were found in the extracts and twenty-six were identified. The main components identified in the extracts in decreasing quantitative order were: curzerene, germacrene B, C(15)H(20)O(2) and beta-elemene for hydrodistillation; C(15)H(20)O(2) and curzerene for SC-CO(2) extracts and 3-hexen-1-ol, curzerene, C(15)H(20)O(2), beta-elemene and germacrene B for SC-CO(2) extracts captured in Porapak-Q. PRACTICAL APPLICATIONS The natural extracts are a potential source of compounds possessing biological activities. They can be used in foods, pharmaceutics and cosmetics. Pitanga is an exotic fruit from Brazil and extracts from its leaves have been used against many diseases in Brazilian folk medicine. Supercritical extraction is an interesting process for the production of natural extracts because it is a clean process and the knowledge of composition of extracts is crucial for the identification of the probable active components.

Iridaea cordata (Gigartinales, Rhodophyta): responses to artificial UVB radiation

The effects of UVB radiation on the different developmental stages of the carrageenan-producing red alga Iridaea cordata were evaluated considering: (1) carpospore and discoid germling mortality; (2) growth rates and morphology of young tetrasporophytes; and (3) growth rates and pigment content of field-collected plant fragments. Unialgal cultures were submitted to 0.17, 0.5, or 0.83 W m(-2) of UVB radiation for 3 h per day. The general culture conditions were as follows: 12 h light/12 h dark cycles; irradiance of 55 mu mol photon. per square meter per second; temperature of 9 +/- 1 degrees C; and seawater enriched with Provasoli solution. All UVB irradiation treatments were harmful to carpospores (0.17 W m(-2) = 40.9 +/- 6.9%, 0.5 W m(-2) = 59.8 +/- 13.4%, 0.83 W m(-2) = 49 +/- 17.4% mortality in 3 days). Even though the mortality of all discoid germlings exposed to UVB radiation was unchanged when compared to the control, those germlings exposed to 0.5 and 0.83 W m(-2) treatments became paler and had smaller diameters than those cultivated under control treatment. Decreases in growth rates were observed in young tetrasporophytes, mainly in 0.5 and 0.83 W m(-2) treatments. Similar effects were only observed in fragments of adult plants cultivated at 0.83 W m(-2). Additionally, UVB radiation caused morphological changes in fragments of adult plants in the first week, while the young individuals only displayed this pattern during the third week. The verified morphological alterations in I. cordata could be interpreted as a defense against UVB by reducing the area exposed to radiation. However, a high level of radiation appears to produce irreparable damage, especially under long-term exposure. Our results suggest that the sensitivity to ultraviolet radiation decreases with increased algal age and that the various developmental stages have different responses when exposed to the same doses of UVB radiation.

Nitrogen Metabolism in leaves of a tank epiphytic bromeliad: Characterization of a spatial and functional division

The leaf is considered the most important vegetative organ of tank epiphytic bromeliads due to its ability to absorb and assimilate nutrients. However, little is known about the physiological characteristics of nutrient uptake and assimilation. In order to better understand the mechanisms utilized by some tank epiphytic bromeliads to optimize the nitrogen acquisition and assimilation, a study was proposed to verify the existence of a differential capacity to assimilate nitrogen in different leaf portions. The experiments were conducted using young plants of Vriesea gigantea. A nutrient solution containing NO(3)(-)/NH(4)(+) or urea as the sole nitrogen source was supplied to the tank of these plants and the activities of urease, nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (NADH-GDH) were quantified in apical and basal leaf portions after 1, 3, 6, 9, 12, 24 and 48 h. The endogenous ammonium and urea contents were also analyzed. Independent of the nitrogen sources utilized, NR and urease activities were higher in the basal portions of leaves in all the period analyzed. On the contrary. GS and GDH activities were higher in apical part. It was also observed that the endogenous ammonium and urea had the highest contents detected in the basal region. These results suggest that the basal portion was preferentially involved in nitrate reduction and urea hydrolysis, while the apical region could be the main area responsible for ammonium assimilation through the action of GS and GDH activities. Moreover, it was possible to infer that ammonium may be transported from the base, to the apex of the leaves. In conclusion, it was suggested that a spatial and functional division in nitrogen absorption and NH(4)(+) assimilation between basal and apical leaf areas exists, ensuring that the majority of nitrogen available inside the tank is quickly used by bromeliad`s leaves. (C) 2011 Elsevier GmbH. All rights reserved.

Constituents of the Leaves of Magnolia ovata

Two new lignans, magnovatins A (1) and B (2), along with nine known compounds, were isolated from the leaves of Magnolia ovata. The known compounds were identified as acuminatin (3), licarin A (4), kadsurenin M, 4-O-demethylkadsurenin M, oleiferin A, oleiferin C, spathulenol, parthenolide, and 11,13-dehydrocompressanolide. In addition, compounds I and 2 yielded four new derivatives (1a, 1b, 2a, and 2b). The structures of the new compounds were established on the basis of spectrometric data evaluation. Free-radical scavenging and antimicrobial activities of the major compounds 1, 3, and 4 were investigated.