Current issues in nerve repair

Although accepted surgical techniques for peripheral nerve repair remain largely unchanged over the past three decades, much progress has been made toward understanding the mechanisms involved in nerve regeneration, and consequently toward providing adjunctive measures to enhance this regenerative process. We present a comprehensive review of the significant advances made in several aspects of nerve repair over the past decade, and particularly the past few years, and provide a few examples of facial nerve repair using the standard neurorrhaphy techniques recommended today. Several conclusions were drawn after thorough review of the literature. Early repair of injured nerves is preferred, and there appears to be no benefit to waiting for 3 weeks. Severed nerves should be repaired with monofilament 9-0 nylon suture placed in epineurial fashion. Fibrin glue confers no benefit in reattaching injured nerves. Likewise, theoretical advantages of laser neurorrhaphy have not resulted in improved nerve regeneration. Finally, trophic factors, such as apolipoproteins and nerve growth factor, and tubulization both appear to offer promise for future experimental and clinical progress in nerve repair. However, further work must be done to prove their efficacy.     

An analytical model for freeboard and in-bed limestone sulfation in fluidized-bed coal combustors

A new model, which combines in-bed and freeboard sulfation, significantly improves the ability to predict sulfur capture by limestone sorbents in fluidized-bed coal combustors. In this model, the in-bed hydrodynamics are described in terms of a bubble phase and an emulsion phase while the freeboard region has only a diluted emulsion phase. The solids, which are in the emulsion phases, are considered to be completely back-mixed; the gaseous bubble phase travels in plug-flow but exchanges with the emulsion phase. The sulfation reaction occurs principally in the emulsion phase and the reaction rate is a direct function of the sulfur dioxide concentration, the extent of the calcium oxide conversion (as measured by a thermogravimetric analyzer), and the amount of limestone present in the bed and in the freeboard. The amount present, or holdup, in the free-board is calculated from empirical correlations for elutriation and from particle-time trajectories as predicted from equations of motion.The model indicates that a significant amount of sulfur capture can occur in the freeboard region, especially with high superficial gas velocities and small particle sizes, both of which lead to increased freeboard holdup. For an overall sulfur retention of 90%, approximately 9% of the sulfur is predicted to be captured within the freeboard above a combustor bed 1.8 m by 1.8 m by 1.2 m high of 1200 μm diameter limestone particles that are fluidized at 2.4 m/s. The model also predicts that the sulfur captured by the entrained particles is negligible. These predictions compare favorably with the actual sulfur retentions experienced in similar sized pilot-scale combustors.     

Forensic autopsies from 1984 to 1993 in Vienna, Austria

In Austria every death is subject to an examination by a medical doctor authorized by the local health authority. If death is suspected to be natural and/or perpetrated by another person, this doctor has to report it to the police. Depending on the investigation results, the examining magistrate in charge demands a judicial autopsy at the Institute of Forensic Medicine. In 1989, 41 murders of old patients by nursing assistants in a Viennese public hospital were disclosed. The main aim of this retrospective study was to determine any change in the demand for forensic autopsies by the Viennese health authority, as well as by the criminal court, after 1989. Furthermore, it was of interest to analyze the reporting practices of medical doctors examining corpses, as well as thr reaction of the criminal court during the study period. After 1989, there was a significant increase of non-judicial and judicial autopsies, performed by Viennese forensic pathologists. In addition, there was a significant increase of reports to the police by coroners as well as by forensic pathologists, paralleled by a higher rate of forensic autopsies demanded by the examining magistrate. This increase of forensic autopsies took place even though the overall rate of deaths in Vienna significantly decreased during the 10-year study period. Thus, the disclosure of 41 murders in the Viennese hospital in 1989 can be assumed as a turning point in the reporting practices of Viennese coroners, as well as the autopsy rate handled by Viennese forensic pathologists.     

Interactions and Chemical Transformations of Coronene Inside and Outside Carbon Nanotubes

By exposing flat and curved carbon surfaces to coronene, a variety of van der Waals hybrid heterostructures are prepared, including coronene encapsulated in carbon nanotubes, and coronene and dicoronylene adsorbed on nanotubes or graphite via π–π interactions. The structure of the final product is determined by the temperature of the experiment and the curvature of the carbon surface. While at temperatures below and close to the sublimation point of coronene, nanotubes with suitable diameters are filled with single coronene molecules, at higher temperatures additional dimerization and oligomerization of coronene occurs on the surface of carbon nanotubes. The fact that dicoronylene and possible higher oligomers are formed at lower temperatures than expected for vapor‐phase polymerization indicates the active role of the carbon surface used primarily as template. Removal of adsorbed species from the nanotube surface is of utmost importance for reliable characterization of encapsulated molecules: it is demonstrated that the green fluorescence attributed previously to encapsulated coronene is instead caused by dicoronylene adsorbed on the surface which can be solubilized and removed using surfactants. After removing most of the adsorbed layer, a combination of Raman spectroscopy and transmission electron microscopy was employed to follow the transformation dynamics of coronene molecules inside nanotubes.     

Locus of control, sex role orientation, and self-concept in Black and White third- and sixth-grade male and female leaders in a rural community.

Examined locus of control among 43 Black boys, 36 White boys, 35 Black girls, and 47 White girls from the 3rd and 6th grades. Ss had been selected as class leaders by their peers. Ss completed the Piers-Harris Children's Self-Concept Scale, the Who Should Test, and the Intellectual Achievement Responsibility Questionnaire. White female leaders were more internally controlled than were Black leaders and attributed good outcomes to personal attributes more often than did Black leaders. White female leaders were also more willing to accept responsibility for bad outcomes than were Black female leaders. Self-concept data and sex-role orientation data were not helpful in interpreting the findings but did serve to suggest several avenues for future research in the area of locus of control. Results do not support the findings of other researchers who found that girls attributed their success to luck or to luck and effort while boys attributed their success to effort. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Management of the clinically positive neck in organ preservation for advanced head and neck cancer

An 82-year-old man was treated with isoniazid (INH) because of a low-grade fever. On the 9th day of treatment, dry coughing and general malaise developed. On the 30th day, he was admitted to our hospital. A chest-X ray film showed infiltrative shadows in the right middle and lower lung fields, but a chest CT scan showed an abnormal lung density in the right lower lobe. Abnormal laboratory findings included leucocytosis, liver dysfunction, hypoxemia, low vital capacity, low diffusing capacity and a high level of C-reactive protein. A differential cell count of the bronchoalveolar lavage fluid (BALF) showed many neutrophils and lymphocytes; examination of a specimen obtained by transbronchial lung biopsy (TBLB) revealed edema of alveolar walls, lymphocyte infiltration, and proliferation of type II alveolar epithelial cells. A drug lymphocyte stimulation test (DLST) against INH was positive. After discontinuation of INH, symptoms resolved, laboratory findings became normal, and the infiltrative shadows in the right middle and lower lung fields disappeared. The clinical course and the findings of BALF, TBLB, and DLST suggested the diagnosis of pneumonitis caused by INH.     

Molecular genetic and protein chemical characterization of the cytochrome ba3 from Thermus thermophilus HB8

Thermus thermophilus HB8 cells grown under reduced dioxygen tensions contain a substantially increased amount of heme A, much of which appears to be due to the presence of the terminal oxidase, cytochrome ba3. We describe a purification procedure for this enzyme that yields approximately 100 mg of pure protein from 2 kg of wet mass of cells grown in < or = 50 microM O2. Examination of the protein by SDS-polyacrylamide gel electrophoresis followed by staining with Coomassie Blue reveals one strongly staining band at approximately 35 kDa and one very weakly staining band at approximately 18 kDa as reported earlier (Zimmermann, B.H., Nitsche, C.I., Fee, J. A., Rusnak, F., and Münck, E. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 5779-5783). By contrast, treatment of the gels with AgNO3 reveals that the larger polypeptide stains quite weakly while the smaller polypeptide stains very strongly. These results suggested the presence of two polypeptides in this protein. Using partial amino acid sequences from both proteins to obtain DNA sequence information, we isolated and sequenced a portion of the Thermus chromosome containing the genes encoding the larger protein, subunit I (cbaA), and the smaller protein, subunit II (cbaB). The two polypeptides were isolated using reversed phase liquid chromatography, and their mole percent amino acid compositions are consistent with the proposed translation of their respective genes. The two genes appear to be part of a larger operon, but we have not extended the sequencing to identify initiation and termination sequences. The deduced amino acid sequence of subunit I includes the six canonical histidine residues involved in binding the low spin heme B and the binuclear center Cu(B)/heme A. These and other conserved amino acids are placed along the polypeptide among alternating hydrophobic and hydrophilic segments in a pattern that shows clear homology to other members of the heme- and copper-requiring terminal oxidases. The deduced amino acid sequence of the subunit II contains the CuA binding motif, including two cysteines, two histidines, and a methionine, but, in contrast to most other subunits II, it has only one region of hydrophobic sequence near its N terminus. Alignment of these two polypeptides with other cytochrome c and quinol oxidases, combined with secondary structure analysis and previous spectral studies, clearly establish cytochrome ba3 as a bona fide member of the superfamily of heme- and copper-requiring oxidases. The alignments further indicate that cytochrome ba3 is phylogenetically distant from other cytochrome c and quinol oxidases, and they substantially decrease the number of conserved amino acid residues.