The importance of pial blood supply to the development of peritumoral brain edema in meningiomas.

In a retrospective analysis, the authors studied the pial and dural blood supplies in 74 intracranial meningiomas and quantified their associated peritumoral brain edema (PTBE). The extent and localization of pial blush in relation to the total tumor volume were determined angiographically. The amount of edema and tumor size were calculated using computerized tomography. The edema-tumor volume ratio was defined as Edema Index (EI). There were 49 meningiomas with PTBE; of those tumors, 46 were supplied by pial vessels, and three were supplied exclusively by dural vessels. Tumors without PTBE showed no pial blush. The mean EI in meningiomas with pial blush was significantly larger (EI = 3) than in meningiomas without pial supply (EI = 1.1; p < 0.0001). Meningiomas with a smaller pial supply than dural supply had a significantly smaller mean EI than tumors with a pial supply equal to or greater than the dural supply (EI = 2.9 vs. EI = 3.7; p < 0.015). In 69.9% of cases with pial blood supply, major portions of the edema were located adjacent to the tumor region supplied by pial vessels. Edema index differences among tumors of different subgroups, as defined by size or histology, were significantly related to the pial supply in each subset. Thus, pial blood supply may be associated with the development of PTBE in meningiomas.

Role of the major antigen of Mycobacterium tuberculosis in cell wall biogenesis.

The dominant exported proteins and protective antigens of Mycobacterium tuberculosis are a triad of related gene products called the antigen 85 (Ag85) complex. Each has also been implicated in disease pathogenesis through its fibronectin-binding capacities. A carboxylesterase domain was found within the amino acid sequences of Ag85A, B, and C, and each protein acted as a mycolyltransferase involved in the final stages of mycobacterial cell wall assembly, as shown by direct enzyme assay and site-directed mutagenesis. Furthermore, the use of an antagonist (6-azido-6-deoxy-alpha, alpha'-trehalose) of this activity demonstrates that these proteins are essential and potential targets for new antimycobacterial drugs.

Structure of the monophosphoryl lipid A moiety obtained from the lipopolysaccharide of Chlamydia trachomatis.

Monophosphoryl lipid A was prepared from the lipopolysaccharide of Chlamydia trachomatis, converted to the methyl ester, and fractionated by reverse-phase high-performance liquid chromatography. The peak fractions were collected and analyzed by mass spectrometry. Matrix-assisted laser desorption/ionization and liquid secondary ion mass spectrometry of the first of two major high-performance liquid chromatographic fractions showed multiple quasi-molecular ions of MNa+ at m/z 1780, 1794, 1808, 1822, and 1836. The positive-ion liquid secondary ion mass spectrometry spectrum also showed a minor series of peaks at m/z 1916, 1930, 1944, 1958, and 1971, consistent with the formation of matrix adducts with 3-nitrobenzyl alcohol. Oxonium ions representing the distal subunit were observed at m/z 1057, 1071, 1085, 1099, and 1113. The second fraction was similarly analyzed and found to contain structural homologs of the first fraction. Based on this study, the major lipid A component of chlamydial lipopolysaccharide is a glucosamine disaccharide that contains five fatty acids and a phosphate in the distal segment. Three fatty acyl groups are in the distal segment, and two are in the reducing end segment. The acyloxyacyl group is located in the distal segment in amide linkage. Two structural series, differing by 14 atomic mass units in the reducing subunit, were observed. Chlamydial lipid A is complex and consists of at least 20 homologous structural components. The relatively low potency of Chlamydia trachomatis lipopolysaccharide in activating lipopolysaccharide-responsive cells might be related to the unusual fatty acid composition of the lipid A moiety.

Bactericidal effect of the Nd:YAG laser in in vitro root canals.

The current study investigates the bactericidal effect of a pulsed Nd:YAG laser on 40, classically prepared, in vitro root canals under standardized conditions. The output of the device including quartz fiber was measured before and after every treatment to exclude any technical faults. A 300-micron fiber was used for the anterior teeth and a 200-micron fiber for the posterior teeth. The Enterococcus faecalis bacteria, as gram-positive cocci, display a heat tolerance in the upper range of the bacilli that can be found in the endodontology and the concentration also reflects the in vivo conditions. The results are quoted in "log kills" in accordance with the work of Rooney et al. On average, 99.91% of the Enterococcus faecalis bacteria injected into the root canals prepared in vitro could be eliminated (97.12% minimum, 99.9997% maximum). This setup suggests that the bactericidal effect of laser therapy in the framework presented here can also be achieved in vivo in clinical cases.

Identification of the apparent carrier in mycolic acid synthesis.

The mycolic acids are large (C70-90) alpha-alkyl, beta-hydroxy fatty acids and are the major determinants of the mycobacterial cell wall's impermeable barrier. The biosynthesis of mycolic acids is barely understood (they are probably the products of specialized elongation and Claisen-type condensation), and yet their synthesis is the site of action of several mainline antituberculosis drugs. We describe the isolation from Mycobacterium smegmatis and the full characterization of a 6-O-mycolyl-beta-D-mannopyranosyl-1-monophosphoryl-3,7,11,15,19,23 ,27- heptamethyl-(2Z,6E,10E)-octacosatrien-1-ol . The identification of a mycolyl-mannosylphosphopolyprenol supported by cell-free labeling experiments and earlier literature suggests unusual biochemical pathways in which mature mycolic acids are formed from beta-oxo precursors while attached to a mannosyl-P-polyprenol, in which form they are transported through the membrane prior to final deposition as arabinan-bound mycolates.

Molecular structures that influence the immunomodulatory properties of the lipid A and inner core region oligosaccharides of bacterial lipopolysaccharides.

The relationship between chain length as well as the position of fatty acyl groups to the ability of lipid A to abolish the expression of suppressor T-cell (Ts) activity was examined. Fatty acyl chain lengths of C12 to C14, as in the lipid A of Escherichia coli and Salmonella minnesota, appear to be optimal for this bioactivity, since lipid A preparations with fatty acyl groups of relatively short chain length (C10 to C12 for Pseudomonas aeruginosa and Chromobacterium violaceum) or predominantly long chain length (C18 for Helicobacter pylori) are without effect. The presence of an acyloxyacyl group of appropriate chain length at the 3' position of the glucosamine disaccharide backbone of lipid A also plays a decisive role. By contrast, the lipid A proximal inner core region oligosaccharides of some bacterial lipopolysaccharides increase the expression of Ts activity; this is due mainly to the capacity of such oligosaccharides, which are relatively conserved in structure among gram-negative bacteria, to enlarge or expand upon the population of CD8+ Ts generated during the course of a normal antibody response to unrelated microbial antigens. The minimal structure required for the expression of the added immunosuppression observed appears to be a hexasaccharide containing one 2-keto-3-deoxyoctonate residue, two glucose residues, and three heptose residues to which are attached two pyrophosphorylethanolamine groups. The relevance of these findings to virulence and to the pathogenesis of gram-negative infections is discussed.

[Paget-von Schroetter syndrome: case description in the light of the literature]. / Paget-von Schroetter-Syndrom: Fallbeschreibung im Spiegel der Literatur.

A 27 year old patient with a thrombosis of the subclavian vein (Paget- von Schroetter's-syndrome) was treated successfully with a systemic streptokinase thrombolysis. Indications and success of the different therapeutic ways in current literature (conventional management, systemic and local thrombolysis) are compared to each other. The authors prefer treatment with systemic thrombolysis, patients with contraindications should be treated with conservative management. Nevertheless no final conclusions can be drawn, as there are no controlled studies comparing the different concepts in treatment.

[Standardization of cerebral imaging by magnetic resonance tomography]. / Standardisierung der zerebralen Bilddarstellung in der Magnetresonanztomographie (MRT).

The complex three-dimensional organisation of the human brain, as well as the numerous variables involved in modern imaging techniques, make it necessary to introduce guidelines for the interpretation of the topographical localisation and allocation of normal cerebral structures and pathological processes. In a historical overview of the methods used for precise localisation we introduce some models that can be used as diagnostic aids. As supporting means in the MRI we suggest the standardisation of the imaging by application of this model. The methodological procedures of its use in the MRI are shown in detail. Finally the advantages and disadvantages of this model are discussed with regard to its possible applications in imaging systems such as MR. The imaging standards for intra-interindividual and inter-methodologic comparison in routine investigations are emphasized in particular.