Selective myotomy in forehead endoscopy

Endoscopic forehead surgery in a subgaleal plane allows selective manipulation of the forehead and glabellar muscles in accordance with their influence in forehead and brow deformity. Myotomy begins by interrupting the blend of the fibers of the elevator and depressor muscles, thereby exposing the bone fixation and cutaneous insertions of the depressor muscles. Myotomy of the depressor group is performed by section of the muscle fibers as close as possible to their bone fixation, with release of the cutaneous insertions at the brow level. The involuntary frontalis contraction free from the active opposition of the depressor muscles and free from the restriction of the inelastic structure of the periosteum stabilizes the brow elevation and gives a natural, long-term result. No fixation methods are used to hold the forehead flap in position. Transverse section of the frontalis muscle is performed to restore brow symmetry or excessive lift of the brow.     

A kinetic model for Xylella fastidiosa adhesion, biofilm formation, and virulence

Xylella fastidiosa is the causal agent of citrus variegated chlorosis and Pierce's disease which are the major threat to the citrus and wine industries. The most accepted hypothesis for Xf diseases affirms that it is a vascular occlusion caused by bacterial biofilm, embedded in an extracellular translucent matrix that was deduced to be the exopolysaccharide fastidian. Fourier transform infrared spectroscopy analysis demonstrated that virulent cells which form biofilm on glass have low fastidian content similar to the weak virulent ones. This indicates that high amounts of fastidian are not necessary for adhesion. In this paper we propose a kinetic model for X. fastidiosa adhesion, biofilm formation, and virulence based on electrostatic attraction between bacterial surface proteins and xylem walls. Fastidian is involved in final biofilm formation and cation sequestration in dilute sap.     

Alternative, cost-effective fungus-staining method for control slides in cytology and histopathology

OBJECTIVE: To develop a cost-effective, reliable and safe method of providing fungal control slides for routine use in pathology laboratories. STUDY DESIGN: A set of easily available, low-cost material was tested to obtain fungal colonies on substrate adequate for paraffin-embedded sections or smears. RESULTS: Such material as cheese is a simple, inexpensive and practical culture medium for silver-positive fungi. A batch of paraffin blocks can be prepared to maintain a stock of control material in the laboratory. CONCLUSION: It is useful to maintain fungal colonies to produce staining control specimens using small pieces of refrigerated cheese to easily produce silver-staining control specimens or smears embedded in paraffin, reducing the risk of accidental exposure to potentially infective pathogens in the laboratory. This method might also be a good alternative for conserving routine surgical specimens, considering the currently decreasing numbers of necropsy and large specimens, particularly from immunosuppressed and infected patients.     

Organic hydroperoxide resistance gene encodes a thiol-dependent peroxidase

ohr (organic hydroperoxide resistance gene) is present in several species of bacteria, and its deletion renders cells specifically sensitive to organic peroxides. The goal of this work was to determine the biochemical function of Ohr from Xylella fastidiosa. All of the Ohr homologues possess two cysteine residues, one of them located in a VCP motif, which is also present in all of the proteins from the peroxiredoxin family. Therefore, we have investigated whether Ohr possesses thiol-dependent peroxidase activity. The ohr gene from X. fastidiosa was expressed in Escherichia coli, and the recombinant Ohr decomposed hydroperoxides in a dithiothreitol-dependent manner. Ohr was about twenty times more efficient to remove organic hydroperoxides than to remove H(2)O(2). This result is consistent with the organic hydroperoxide sensitivity of Delta ohr strains. The dependence of Ohr on thiol compounds was ascertained by glutamine synthetase protection assays. Approximately two thiol equivalents were consumed per peroxide removed indicating that Ohr catalyzes the following reaction: 2RSH + ROOH --> RSSR + ROH + H(2)O. Pretreatment of Ohr with N-ethyl maleimide and substitution of cysteine residues by serines inhibited this peroxidase activity indicating that both of the Ohr cysteines are important to the decomposition of peroxides. C125S still had a residual enzymatic activity indicating that Cys-61 is directly involved in peroxide removal. Monothiol compounds do not support the peroxidase activity of Ohr as well as thioredoxin from Saccharomyces cerevisiae and from Spirulina. Interestingly, dithiothreitol and dyhydrolipoic acid, which possess two sulfhydryl groups, do support the peroxidase activity of Ohr. Taken together our results unequivocally demonstrated that Ohr is a thiol-dependent peroxidase.     

Molecular typing of clinical and environmental Cryptococcus neoformans isolates in the Brazilian state Rio Grande do Sul

In Brazil, 4.5% of the AIDS-related opportunistic infections are caused by Cryptococcus neoformans. This pathogen is a ubiquitous environmental basidiomycetous encapsulated yeast, commonly found in soil and avian excreta. The present study investigates further the population structure of clinical and environmental C. neoformans isolates from south Brazil. One hundred five clinical and 19 environmental (pigeon excreta and Eucalyptus spp.) isolates from the Brazilian state Rio Grande do Sul were characterized based on morphological, biochemical, molecular and serological data. The majority of the clinical and environmental isolates analyzed belonged to C. neoformans var. grubii serotype A (89.5 and 52.6%, respectively), were mating type alpha (98.1 and 94.7%, respectively) and were phospholipase-positive (94.3 and 73.7%, respectively). PCR-fingerprinting with the microsatellite-specific primer M13 and the minisatellite-specific primer (GACA)(4) grouped the majority of the isolates into the molecular type VNI (89.5 of the clinical and 52.6% of the environmental isolates). Our results add considerable new information to the few available data on ecology, molecular biology and epidemiology of C. neoformans in the southern region of Brazil.     

Determination of cocaine, benzoylecgonine and cocaethylene in human hair by solid-phase microextraction and gas chromatography-mass spectrometry

The present work describes a highly precise and sensitive method developed to detect cocaine (COC), benzoylecgonine (BE, its main metabolite) and cocaethylene (CE, transesterification product of the coingestion of COC with ethanol) in human head hair samples. The method was based on an alkylchloroformate derivatization of benzoylecgonine and the extraction of the analytes by solid-phase microextraction (SPME). Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring mode (SIM). The limits of quantification and detection (LOQ and LOD) were: 0.1 ng/mg for COC and CE, and 0.5 ng/mg for BE. Good inter- and intra-assay precision was observed. The dynamic range of the assay was 0.1-50 ng/mg. The method is not time consuming and was shown to be easy to perform.     

Phylogeography of the Madeiran endemic lizard Lacerta dugesii inferred from mtDNA sequences

Partial sequences from two mitochondrial DNA genes, cytochrome b and 12S rRNA, were used to assess the phylogenetic relationships of populations of Lacerta dugesii from the volcanic Atlantic islands of Madeira, the Desertas, Porto Santo, and the Selvagens. All four-island groups are genetically distinguishable and populations within each contain similar degrees of genetic diversity. Molecular clock estimates suggest that the islands were colonized much later after their emergence compared to other Atlantic islands, possibly due to their greater geographical isolation. Mismatch analysis of all populations is consistent with exponential growth, as expected after colonization of empty niches. The Selvagens contain genetic substructuring between the islets.