Effect of cell therapy with allogeneic osteoblasts on bone repair of rat calvaria defects

Background aims

Regenerative medicine strategies based on cell therapy are considered a promising approach to repair bone defects. The aims of this study were to evaluate the effect of subculturing on the osteogenic potential of osteoblasts derived from newborn rat calvaria and the effect of these osteoblasts on bone repair of rat calvaria defects.

Biofilm formation and antimicrobial sensitivity of lactobacilli contaminants from sugarcane-based fuel ethanol fermentation

Industrial ethanol fermentation is subject to bacterial contamination that causes significant economic losses in ethanol fuel plants. Chronic contamination has been associated with biofilms that are normally more resistant to antimicrobials and cleaning efforts than planktonic cells. In this study, contaminant species of Lactobacillus isolated from biofilms (source of sessile cells) and wine (source of planktonic cells) from industrial and pilot-scale fermentations were compared regarding their ability to form biofilms and their sensitivity to different antimicrobials. Fifty lactobacilli were isolated and the most abundant species were Lactobacillus casei, Lactobacillus fermentum and Lactobacillus plantarum. The majority of the isolates (87.8%) were able to produce biofilms in pure culture. The capability to form biofilms and sensitivity to virginiamycin, monensin and beta-acids from hops, showed inter- and intra-specific variability. In the pilot-scale fermentation, Lactobacillus brevis, L. casei and the majority of L. plantarum isolates were less sensitive to beta-acids than their counterparts from wine; L. brevis isolates from biofilms were also less sensitive to monensin when compared to the wine isolates. Biofilm formation and sensitivity to beta-acids showed a positive and negative correlation for L. casei and L. plantarum, respectively.     

Effect of heavy metals on chromatin supraorganization, nuclear phenotypes, and survival ofTriatoma infestans

The nuclear phenotypes and survival of the hemipteran,Triatoma infestans (Hemiptera, Reduviidae), were studied in specimens treated with copper sulfate and methylmercury. The objective was to determine whether changes in chromatin supraorganization and insect survival similar to those promoted by other stressing agents could also be induced by heavy metals. At the concentrations used, copper sulfate and methylmercury were toxic to the cells, mainly inducing nuclear degenrration in the Malpighian tubules and being lethal to a large part of the insect population. Although some individual resistance was found, especially in fasted specimens, heavy metals were found to be much more lethal than was, for instance, a thermal shock at 0°C for 12 h. The nuclear phenotypes detected after heavy metal treatment were similar to those reported under other stressing conditions. However, the frequency at which nuclei exhibited aspects of heterochromatin unraveling was much higher than that found in fasted and thermal-shocked specimens, and was independent of the heavy metal type used. If this phenotype represents an attempt to improve opportunities for extensive cell and insect survival, it was not sufficiently effective. In 5th instar nymphs, the effect of CuSO₄ on chromatin supraorganization was detected at early steps of spermatogenesis but not in the cells which were at late spermiogenesis when the metal was administered. This is probably due to changes in nuclear protein composition and to the tightly packed state of the DNA-protein complexes occurring at spermiogenesis, which may protect chromatin from damages. However, when CuSO₄ was supplied to 4th instar nymphs, it slowed down the spermiogenesis process, possibly due to several factors including Cu²⁺ binding to DNA phosphates.     

<Emphasis Type="Italic">Ilex paraguariensis</Emphasis> Pellets from a Spray-Dried Extract: Development,Characterization, and Stability

Several studies have shown the potential use of Ilex paraguariensis in developing products with the aim to protect biological systems against oxidative stress-mediated damages. In the same way, technological studies have demonstrated the feasibility of obtaining dry products, by spray-drying process, from aqueous extracts of I. paraguariensis in laboratory. The present work was designed to develop pellets by extrusion/spheronization process, from an I. paraguariensis spray-dried powder. The pellets were characterized with respect to their chemical, physical, and technological properties, and the thermal and the photostability of the main polyphenol constituents were investigated. The pellets exhibited adequate size, shape, and high process yield (78.7%), as well as a good recovery of the total polyphenols (>95%) and a good dissolution in water (89.44 to 100.05%). The polyphenols were stable against light when conditioned in amber glass bottles; unstable against heat when the samples were conditioned either in open glass bottles or in hermetically sealed glass bottles and demonstrated to be hygroscopic and sensible to the temperature, especially when stored in permeable flasks. These findings pointed to the relevance of reducing the residual moisture content of pellets as well as of conditioning them in opaque humidity tight packages under low temperatures. The feasibility of obtaining pellets from an I. paraguariensis spray-dried powder using extrusion/spheronization technique was, for the first time, demonstrated. This finding represents a novelty for the herbal products in both pharmaceutical and food fields.     

The physiological basis of seed dormancy in Avena fatua. II. On the involvement of alternative respiration in the stimulation of germination by sodium azide

Chromatography on DEAE-cellulose of an extract from etiolated leaves of sorghum ( Sorghum vulgare Pers. cv. INRA 450), a C₄ plant, gave only one form of phosphoenol pyruvate carboxylase with functional and regulatory properties of a C₃ type plant enzyme. Greening of the leaves resulted in a significant increase in activity. This increase was due to the appearance of a new form of the enzyme, which eluted at lower ionic strength and exhibited new properties. This form was glucose-6-P activated and showed a sigmoidal curve response to the concentration of the substrate phosphoerralpyruvate. These kinetic properties are typical of a C₄ plant enzyme.     

Spectroscopic and electrochemical characterization of gold(I) and gold(III) complexes with glyoxaldehyde bis(thiosemicarbazones): cytotoxicity against human tumor cell lines and inhibition of thioredoxin reductase activity

Complexes [Au(2)(H(2)Gy3DH)(2)]Cl(2) (1), [Au(H(2)Gy3Me)]Cl(3) (2) and [Au(H(2)Gy3Et)]Cl(3) (3) were obtained with glyoxaldehyde bis(thiosemicarbazone) (H(2)Gy3DH) and its N(3)-methyl (H(2)Gy3Me) and N(3)-ethyl (H(2)Gy3Et) derivatives. The bis(thiosemicarbazones) and their gold(I) and gold(III) complexes exhibited anti-proliferative activity against HL-60, Jurkat (leukemia) and MCF-7 (breast cancer) cells at 10 μmol L(-1). Complex (2) was able to in vitro inhibit thioredoxin reductase (TrxR) activity, which suggests that inhibition of TrxR could be part of its mechanism of action.     

The function of Alr1p of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> in cadmium detoxification: Insights from phylogenetic studies and particle-induced X-ray emission

Two genes in Saccharomyces cerevisiae, ALR1 and ALR2, encode transmembrane proteins involved in Mg²⁺ uptake. The present study investigates the phylogenetic relationship of Alr1p/Alr2p with bacterial CorA proteins and some proteins related to Mg²⁺influx/efflux transport in mitochondrial and bacterial zinc transporters; including hydrophobic cluster analysis (HCA). The phylogenetic results indicate that the Alrp sequences of S. cerevisiae share a common carboxy-terminus with proteins related to zinc efflux transport. We also analyse the intracellular metal content by particle-induced X-ray emission (PIXE) after cell exposure to cadmium. The PIXE analysis of cadmium-exposed ALR mutants and wild-type yeast cells suggests that Alrp has a central role in cell survival in a cadmium-rich environment. Published online December 2004 Ana Lúcia Kern, Diego Bonatto: Both authors contributed equally to this work.     

The Pmr1 protein, the major yeast Ca2+-ATPase in the Golgi, regulates intracellular levels of the cadmium ion

Cadmium is a nonessential, highly toxic heavy metal that shows ionic properties similar to calcium. These ionic similarities imply that the cadmium ion, Cd²⁺, is a calcium ion, Ca²⁺, receptor-agonist, affecting the same biochemical pathways involved in Ca²⁺ homeostasis. In the yeast Saccharomyces cerevisiae , the PMC1 and PMR1 genes encode vacuolar and Golgi Ca²⁺-ATPases, respectively. The PMR1 protein product Pmr1p is involved in both Ca²⁺ and Mn²⁺ homeostasis. This study investigated the importance of Pmc1p and Pmr1p for Cd²⁺ cellular detoxification. Using the standard techniques of yeast molecular research and a multielemental procedure named particle-induced X-ray emission, Pmr1p was identified as a protein that directly participates in the detoxification of Cd²⁺, possibly through the secretory pathway. The results allow us to posit a model of Cd²⁺ detoxification where Pmr1p has a central role in cell survival in a Cd²⁺-rich environment.     

Involvement of peripheral TRPV1 in TMJ hyperalgesia induced by ethanol withdrawal

Ethanol withdrawal increases nociception after the injection of formalin into the rat's temporomandibular joint (TMJ). Little is known about the neurological basis for hyperalgesia induced by ethanol withdrawal, but it has been reported that ethanol can potentiate the response of transient receptor potential vanilloid receptor-1 (TRPV1) in superficial tissues. The present study was designed to test the hypothesis that peripheral TRPV1 could be involved on nociceptive behavioral responses induced by the injection of formalin into the TMJ region of rats exposed to chronic ethanol administration and ethanol withdrawal. Behavioral hyperalgesia was verified 12 h after ethanol withdrawal in rats that drank an ethanol solution (6.5%) for 10 days. In another group submitted to the same ethanol regimen, the selective vanilloid receptor antagonist capsazepine (300, 600 or 1200 microg/25 microl) or an equal volume of vehicle were injected into the TMJ regions 30 min before the TMJ formalin test. The local injections of capsazepine reduced the increased nociceptive responses induced by ethanol withdrawal. The effect of capsazepine on rats that did not drink ethanol was not significant. These results indicate that the peripheral TRPV1 can contribute to the hyperalgesia induced by ethanol withdrawal on deep pain conditions.