Cyclooxygenase-2 inhibition does not impair block bone grafts healing in rabbit model

Success of alveolar reconstructions using onlay autogenous block bone grafts depends on their adequate integration to the recipient bed influenced by a number of local molecules. Considering the fundamental role of cyclooxygenase (COX-2) in bone repair, the aim of this study was to analyze the effect of its inhibition in the integration of endochondral (EC) iliac crest, and intramembranous (IM) calvaria bone grafts. Thirty-two rabbits were divided into 4 groups: Calvaria Control (CC) and Iliac Control—treated with oral 0.9 % saline solution, and Calvarial-NSAID (C-NSAID) and Iliac-NSAID (I-NSAID) groups—treated with oral 6 mg/Kg non-steroidal anti-inflammatory drug etoricoxib. After 7, 14, 30 and 60 days the animals were euthanized and the specimens removed for histological, histomorphometric and immunohistochemistry analysis. At day 60, a tight integration of IM blocks could be seen with the presence of remodeling bone, whereas integration of EC grafts was mainly observed at the edges of the grafts. A significant higher percentage of bone matrix in the interface region of the CC grafts in comparison to C-NSAID only at day 14, whereas no differences were detected comparing the EC grafts. No differences were observed in Runx-2 and vascular endothelial growth factor (VEGF) immunolabeling when comparing CC and C-NSAID groups, while a significant weaker Runx-2 and VEGF labeling was detected in I-NSAID group at day 60. Although some influence was detected in osteogenesis, it is concluded that drug induced inhibition of COX-2 does not impair onlay bone grafts’ healing of both embryologic origins in rabbits.     

γ-Glutamyltranspeptidases in the metabolism of γ-glutamyl peptides in plants

The activity and specificity of γ-glutamyltranspeptidase in immature seeds of some leguminous plants did not reflect the γ-glutamyl peptide pattern     

Conspicuous Growth of Intravenously Inoculated Staphylococcus aureus in Subcutaneously Established Ehrlich Ascites Tumor Tissue of Mice

Intratumoral growth of Staphylococcus aureus was compared with the intrarenal growth, to examine the usefulness of the method as a marker of its pathogenicity. When 5 × 10⁷ CFU/mouse of three derivatives from S. aureus Cowan I with different intrarenal growth were intravenously injected into Ehrlich tumor-bearing mice, they lodged in the tumor tissue at approximately 10³ CFU/0.1 g by 30 min after infection, and grew in the range of 10⁶ CFU/0.1 g to 10⁸ CFU/0.1 g by day 4, regardless of their intrarenal growth capacity. In contrast, S. saprophyticus lodged in both tissues to the same degree as S. aureus, but did not grow at all. The time course of the staphylococcal growth was different between tumor tissue and kidney, suggesting differences in the local responses against S. aureus.     

Signal-sensing mechanisms of the putative osmosensor KdpD in Escherichia coli

The KdpD protein is a membrane-located sensory kinase (or signal transducer) critically involved in the regulation of the kdpABC operon that is responsible for a high-affinity transport system in Escherichia coli. In this study, a set of KdpD mutants, each resulting in a single amino acid substitution around the membrane-spanning regions of KdpD, was isolated. Amino acid substitutions in these KdpD mutants were located non-randomly, particularly within the C-terminal half of the membrane-spanning regions. This set of KdpD mutants exhibited altered transmembrane-signalling properties in response to external K⁺ and other stimuli. In particular, these mutants were found to be insensitive, if not completely, to the K⁺ signal. However, they were able to respond to other stimuli such as high-salt stress, as in the wild type. Therefore, in contrast to the wild type, the cells carrying these mutations exhibited high levels of the steady-state expression of kdp, regardless of external K⁺, provided that high concentrations of ionic solutes were supplemented to the cultures. More interestingly, the set of KdpD mutants could also respond to high concentrations of external non-ionic solutes such as sucrose and D-arabinose, thereby increasing substantially the steady-state expression of kdp in response to the medium osmolarity. Furthermore, it was found that certain chemicals, ethanol, chlorpromazine and procaine, could function as effectors for the KdpD mutants at relatively low concentrations in the media. Based on these findings, we have examined the primary signal(s) that regulates the function of KdpD. We propose here that KdpD can be considered to be an environmental sensor that exhibits sensing mechanisms in response to both the level of K⁺ and the physico-chemical state of the cytoplasmic membrane.     

First description of Candida nivariensis in Brazil: antifungal susceptibility profile and potential virulence attributes

This study evaluated the antifungal susceptibility profile and the production of potential virulence attributes in a clinical strain of Candida nivariensis for the first time in Brazil, as identified by sequencing the internal transcribed spacer (ITS)1-5.8S-ITS2 region and D1/D2 domains of the 28S of the rDNA. For comparative purposes, tests were also performed with reference strains. All strains presented low planktonic minimal inhibitory concentrations (PMICs) to amphotericin B (AMB), caspofungin (CAS), and voriconazole. However, our strain showed elevated planktonic MICs to posaconazole (POS) and itraconazole, in addition to fluconazole resistance. Adherence to inert surfaces was conducted onto glass and polystyrene. The biofilm formation and antifungal susceptibility on biofilm-growing cells were evaluated by crystal violet staining and a XTT reduction assay. All fungal strains were able to bind both tested surfaces and form biofilm, with a binding preference to polystyrene (p < 0.001). AMB promoted significant reductions (≈50%) in biofilm production by our C. nivariensis strain using both methodologies. This reduction was also observed for CAS and POS, but only in the XTT assay. All strains were excellent protease producers and moderate phytase producers, but lipases were not detected. This study reinforces the pathogenic potential of C. nivariensis and its possible resistance profile to the azolic drugs generally used for candidiasis management.