EpCAM regulates cell cycle progression via control of cyclin D1 expression.

The epithelial cell adhesion molecule (EpCAM) is an integral transmembrane protein that is frequently overexpressed in embryonic stem cells, tissue progenitors, carcinomas and cancer-initiating cells. In cancer cells, expression of EpCAM is associated with enhanced proliferation and upregulation of target genes including c-myc. However, the exact molecular mechanisms underlying the observed EpCAM-dependent cell proliferation remained unexplored. Here, we show that EpCAM directly affects cell cycle progression via its capacity to regulate the expression of cyclin D1 at the transcriptional level and depending on the direct interaction partner FHL2 (four-and-a-half LIM domains protein 2). As a result, downstream events such as phosphorylation of the retinoblastoma protein (Rb) and expression of cyclins E and A are similarly affected. In vivo, EpCAM expression strength and pattern are both positively correlated with the proliferation marker Ki67, high expression and nuclear localisation of cyclin D1, and Rb phosphorylation. Thus, EpCAM enhances cell cycle progression via the classical cyclin-regulated pathway.

Wear of nickel-titanium lightspeed instruments evaluated by scanning electron microscopy.

Used rotary nickel-titanium instruments require frequent replacing. This laboratory study evaluated defects of Lightspeed cutting tips before and after usage. The instruments were fixed into custom-made holders, the cutting heads photographed in a scanning electron microscope at x120 to x400 magnification at preset points around the cutting tip (90, 180, 270 and 360 degrees) and head-on. Instrument sizes 20 to 32.5, 35 to 60, and 65 to 100 were used in 9, 18, and 36 canals, respectively, and autoclaved after shaping every third root canal. The used instruments were cleaned and then reexamined in a scanning electron microscope as before. The presence of 11 types of conditions was scored from the pre- and postusage photographs. No instruments fractured during the test, but all the cutting heads had one or more imperfections, even before usage. The presence of debris, pitting, and metal strips changed significantly. Imperfections were found on new and used Lightspeed cutting heads, indicating the general difficulty in machining defect-free nickel-titanium rotary instruments. However, high quality should remain a goal to improve instrument efficiency.

Laccase is essential for lignin degradation by the white-rot fungus Pycnoporus cinnabarinus.

The white-rot fungus, Pycnoporus cinnabarinus, provides an excellent model organism to elucidate the controversial role of laccase in lignin degradation. P. cinnabarinus produces laccase in one isoform as the predominant phenoloxidase in ligninolytic cultures, and neither LiP nor MnP are secreted. Yet, P. cinnabarinus degrades lignin very efficiently. In the present work, we show that laccase-less mutants of P. cinnabarinus were greatly reduced in their ability to metabolize 14C ring-labeled DHP. However, 14CO2 evolution in these mutant cultures could be restored to levels comparable to those of the wild-type cultures by addition of purified P. cinnabarinus laccase. This clearly indicates that laccase is absolutely essential for lignin degradation by P. cinnabarinus.

A fungal metabolite mediates degradation of non-phenolic lignin structures and synthetic lignin by laccase.

Lignin peroxidase is generally considered to be a primary catalyst for oxidative depolymerization of lignin by white-rot fungi. However, some white-rot fungi lack lignin peroxidase. Instead, many produce laccase, even though the redox potentials of known laccases are too low to directly oxidize the non-phenolic components of lignin. Pycnoporus cinnabarinus is one example of a laccase-producing fungus that degrades lignin very efficiently. To overcome the redox potential barrier, P. cinnabarinus produces a metabolite, 3-hydroxyanthranilate that can mediate the oxidation of how non-phenolic substrates by laccase. This is the first description of how laccase might function in a biological system for the complete depolymerization of lignin.

The ligninolytic system of the white rot fungus Pycnoporus cinnabarinus: purification and characterization of the laccase.

The white rot fungus Pycnoporus cinnabarinus was characterized with respect to its set of extracellular phenoloxidases. Laccase was produced as the predominant extracellular phenoloxidase in conjunction with low amounts of an unusual peroxidase. Neither lignin peroxidase nor manganese peroxidase was detected. Laccase was produced constitutively during primary metabolism. Addition of the most effective inducer, 2,5-xylidine, enhanced laccase production ninefold without altering the isoenzyme pattern of the enzyme. Laccase purified to apparent homogeneity was a single polypeptide having a molecular mass of approximately 81,000 Da, as determined by calibrated gel filtration chromatography, and a carbohydrate content of 9%. The enzyme displayed an unusual behavior on isoelectric focusing gels; the activity was split into one major band (pI, 3.7) and several minor bands of decreasing intensity which appeared at regular, closely spaced intervals toward the alkaline end of the gel. Repeated electrophoresis of the major band under identical conditions produced the same pattern, suggesting that the laccase was secreted as a single acidic isoform with a pI of about 3.7 and that the multiband pattern was an artifact produced by electrophoresis. This appeared to be confirmed by N-terminal amino acid sequencing of the purified enzyme, which yielded a single sequence for the first 21 residues. Spectroscopic analysis indicated a typical laccase active site in the P. cinnabarinus enzyme since all three typical Cu(II)-type centers were identified. Substrate specificity and inhibitor studies also indicated the enzyme to be a typical fungal laccase. The N-terminal amino acid sequence of the P. cinnabarinus laccase showed close homology to the N-terminal sequences determined for laccases from Trametes versicolor, Coriolus hirsutus, and an unidentified basidiomycete, PM1. The principal features of the P. cinnabarinus enzyme system, a single predominant laccase and a lack of lignin- or manganese-type peroxidase, make this organism an interesting model for further studies of possible alternative pathways of lignin degradation by white rot fungi.

[Computer tomography following hypophysectomy]. / Computertomographie nach Hypophysektomie.

The authors analyzed the computerized tomograms of 17 patients who had been operated on for tumors in the sellar region. After pituitectomy from a transnasal approach the following was observed: bone defects in the area of the posterior ethmoid cells and at the sphenoid sinus (1), partial absence of the sellar floor (4), a shadow on the ethmoid and sphenoid sinuses (2), an empty sella (1), damaged tissue in the sellar region (1) and blood in the area operated on (1). After pituitectomy from a transcranial approach, the following was seen: trepanation damage frontoparietally on the right (6), trepanation damage frontoparietally on the left (3), brain substance damage below the trepanation (4), and an empty sella (5). The following had occurred as a result of the primary disorder: expansion of the sella (twice), a displacement of the middle structures (twice), bone arrosion in the sella area (once) and a tumor picture in the pituitary area (in eight cases). Air may be encountered postoperatively in the various regions within the calvaria. For the first two weeks at least, its existence is not indicative of the presence of a liquor fistula.

[Computed tomography following facial surgery]. / Computertomographie nach Gesichtschirurgie.

During the first four to six weeks after surgery, a reaction in the paranasal sinuses can be demonstrated by CT. Similar opacifications appearing later were due to tumor recurrency. Tumor recurrency leads to an increase of soft tissue structures, disappearance of vascular structures, and an increase of bone destruction. The bone destruction can show characteristic fragmentation, with the fragments at a certain distance from each other. If the recurrence is known, CT shows the extension, similar to normal preoperative CT. Follow-up examinations improve safety of interpretation.