Electronic structure of a σ-FeCr compound.

The electronic structure of a σ-FeCr compound in a paramagnetic state was calculated for the first time in terms of isomer shifts and quadrupole splittings. The former were calculated using the charge self-consistent Korringa-Kohn-Rostoker (KKR) Green's function technique, while the latter were estimated from an extended point charge model. The calculated quantities combined with recently measured site occupancies were successfully used to analyze a Mössbauer spectrum recorded at room temperature using only five fitting parameters namely background, total intensity, linewidth, IS0 (necessary to adjust the refined spectrum to the used Mössbauer source) and the QS proportionality factor. Theoretically determined changes of the isomer shift for the σ-FeCr sample were found to be in line with the corresponding ones measured on a α-FeCr sample.

[Incidence, latency, and prognosis of local and regional recurrences in patients with upper aerodigestive tract cancer treated by laser microsurgery: influence of initial tumor parameters]. / Lokale und regionäre Rezidive von laserchirurgisch behandelten Plattenepithelkarzinomen des oberen Aerodigestivtrakts: Häufigkeit, Latenz und Prognose sowie Einfluss der initialen Tumorparameter.

INTRODUCTION: The aim of the present study is to identify clinical factors that influence the incidence and the prognosis of local and regional recurrences. PATIENTS AND METHODS: The data of 1,426 patients with newly diagnosed squamous cell carcinoma of the upper aerodigestive tract who were treated by curative laser microsurgery between August 1986 and December 2002 were reviewed. RESULTS: In 381 patients (27%), tumor recurrences were detected during follow-up. The frequency of local as well as regional recurrences significantly correlated with the initial stage of tumors. Recurrences of advanced carcinomas occurred considerably sooner than those of stage II and I cancer. During the 4th year of follow-up, patients with early stage disease had a recurrence rate twice as high as those with advanced carcinomas. Survival with recurrence was adversely affected by adjuvant radiotherapy as part of initial treatment, simultaneous local and regional manifestation of recurrence, male sex, advanced stage of initial disease, and by oral or hypopharyngeal site of the primary tumor. CONCLUSION: Early carcinomas of the upper aerodigestive tract recur at a lower rate than advanced stage diseases, but after a longer mean latency period. As a consequence, these patients should receive close follow-up also during the 3rd and 4th years after treatment, particularly as the prognosis of their recurrences is most often favorable.

Primary cutaneous Mycobacterium avium complex infection following squamous cell carcinoma excision.

Primary cutaneous Mycobacterium avium complex (MAC) infection is rare, particularly among immunocompetent patients. We present the case of a purportedly healthy patient with primary cutaneous MAC infection arising within the excision margins of multiple infiltrating squamous cell carcinomas.

Oligonucleotide inhibitors of human thrombin that bind distinct epitopes.

Thrombin, a multifunctional serine protease, recognizes multiple macromolecular substrates and plays a key role in both procoagulant and anticoagulant functions. The substrate specificity of thrombin involves two electropositive surfaces, the fibrinogen-recognition and heparin-binding exosites. The SELEX process is a powerful combinatorial methodology for identifying high-affinity oligonucleotide ligands to any desired target. The SELEX process has been used to isolate single-stranded DNA ligands to human thrombin. Here, a 29-nucleotide single-stranded DNA ligand to human thrombin, designated 60-18[29], with a Kd of approximately 0.5 nM is described. DNA 60-18[29] inhibits thrombin-catalyzed fibrin clot formation in vitro. Previously described DNA ligands bind the fibrinogen-recognition exosite, while competition and photocrosslinking experiments indicate that the DNA ligand 60-18[29] binds the heparin-binding exosite. DNA 60-18[29] is a quadruplex/duplex with a 15-nucleotide "core" sequence that has striking similarity to previously described DNA ligands to thrombin, but binds with 20 to 50-fold higher affinity. The 15-nucleotide core sequence has eight highly conserved guanine residues and forms a G-quadruplex structure. A single nucleotide within the G-quadruplex structure can direct the DNA to a distinct epitope. Additional sequence information in the duplex regions of ligand 60-18[29] contribute to greater stability and affinity of binding to thrombin. A low-resolution model for the interaction of DNA 60-18[29] to human thrombin has been proposed.

Results on quantitative trait loci for flushing date in oaks can be transferred to different segregating progenies.

Flushing date (bud burst) is one of the most important traits for the adaptation to different environments and climates in the temperate zone. Because of their wide geographic distribution, Quercus robur L. and Q. petraea (Matt.) Liebl. are suitable as model plants to study the genetic basis of bud burst. QTLs (Quantitative Trait Loci) with comparatively large effects have been mapped in a former study in a Q. robur x Q. robur full-sib family (French cross). In the present study, we performed a Bulked Segregant Analysis (BSA) in the F (1) progeny comprising 144 seedlings derived from a cross between a single Q. robur tree as common seed parent and five different pollen donors both from Q. robur and Q. petraea (Q. robur x Q. spp., Diekholzen crosses). In addition, markers linked to two bud burst QTLs with comparably strong effect in the above-mentioned full-sib family (French cross) were tested for their association with bud burst in the Q. robur x Q. spp. (Diekholzen) progeny. Using three microsatellite markers as anchor points, we could map QTLs on linkage group 7 and on linkage group 2, together explaining 16.2 % of the total phenotypic variance (PVE) in 1999 and 38.1 % in 2003. Out of 10 markers that segregated in both mapping progenies, four markers including the two microsatellite markers, showed a significant effect on bud burst in both materials. At microsatellite loci ssrQpZAG1/5 (linkage group 7) and ssrQpZAG119 (linkage group 2) alleles associated with early (allele 166 bp in ssrQpZAG1/5) and late bud burst (allele 57 bp in ssrQpZAG119) in the Q. robur x Q. robur full-sib family (French cross) showed a highly significant association with the same polarity of the effect in the Q. robur x Q. spp. (Diekholzen) progeny. The usefulness of these markers for marker-assisted selection in full-sib and half-sib families is discussed.

Determination of ochratoxin A in green coffee by immunoaffinity column cleanup and liquid chomatography: collaborative study.

A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol-3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of < 0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (< 0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of < or = 0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.

Structure of the xylanase from Penicillium simplicissimum.

Despite its relatively low pH and temperature optimum, the xylanase from Penicillium simplicissimum performs exceedingly well under conditions of paper bleaching. We have purified and characterized this enzyme, which belongs to family 10 of glycosyl hydrolases. Its gene was cloned, and the sequence of the protein was deduced from the nucleotide sequence. The xylanase was crystallized from ammonium sulfate at pH 8.4, and X-ray data were collected at cryo-temperature to a crystallographic resolution of 1.75 A. The crystal structure was solved by molecular replacement using the catalytic domain of the Clostridium thermocellum xylanase as a search model, and refined to a residual of R = 20% (R(free) = 23%) for data between 10 and 1.75 A. The xylanase folds in an (alpha/beta)8 barrel (TIM-barrel), with additional helices and loops arranged at the "top" forming the active site cleft. In its overall shape, the P. simplicissimum xylanase structure is similar to other family 10 xylanases, but its active site cleft is much shallower and wider. This probably accounts for the differences in catalysis and in the mode of action of this enzyme. Three glycerol molecules were observed to bind within the active site groove, one of which interacts directly with the catalytic glutamate residues. It appears that they occupy putative xylose binding subsites.

Reinforcement of genetic coherence in a two-locus model.

BACKGROUND: In order to maintain populations as units of reproduction and thus enable anagenetic evolution, genetic factors must exist which prevent continuing reproductive separation or enhance reproductive contact. This evolutionary principle is called genetic coherence and it marks the often ignored counterpart of cladistic evolution. Possibilities of the evolution of genetic coherence are studied with the help of a two-locus model with two alleles at each locus. The locus at which viability selection takes place is also the one that controls the fusion of gametes. The second locus acts on the first by modifying the control of the fusion probabilities. It thus acts as a mating modifier whereas the first locus plays the role of the object of selection and mating. Genetic coherence is enhanced by modifications which confer higher probabilities of fusion to heterotypic gametic combinations (resulting in heterozygous zygotes) at the object locus. RESULTS: It is shown that mutants at the mating modifier locus, which increase heterotypic fusions but do not lower the homotpyic fusions relative to the resident allele at the object locus, generally replace the resident allele. Since heterozygote advantage at the object locus is a necessary condition for this result to hold true, reinforcement of genetic coherence can be claimed for this case. If the homotypic fusions are lowered, complex situations may arise which may favor or disfavor the mutant depending on initial frequencies and recombination rates. To allow for a generalized analysis including alternative models of genetic coherence as well as the estimation of its degrees in real populations, an operational concept for the measurement of this degree is developed. The resulting index is applied to the interpretation of data from crossing experiments in Alnus species designed to detect incompatibility relations.

Kinetic studies on the enzyme (S)-hydroxynitrile lyase from hevea brasiliensis using initial rate methods and progress curve analysis

(S)-Hydroxynitrile lyase (EC 4.1.2.39) from Hevea brasiliensis(rubber tree) catalyzes the reversible cleavage of cyanohydrins to aldehydes or ketones and prussic acid (HCN). Enzyme kinetics in both directions was studied on a model system with mandelonitrile, benzaldehyde, and HCN using two different methods-initial rate measurements and progress curve analysis. To discriminate between possible mechanisms with the initial rate method, product inhibition was studied. Benzaldehyde acts as a linear competitive inhibitor against mandelonitrile whereas HCN shows S-linear I-parabolic mixed-type inhibition. These results indicate an Ordered Uni Bi mechanism with the formation of a dead-end complex of enzyme, (S)-mandelonitrile and HCN. Prussic acid is the first product released from the enzyme followed by benzaldehyde. For progress curve analysis, a kinetic model of an Ordered Uni Bi mechanism including a dead-end complex, enzyme inactivation, and the chemical parallel reaction was set up, which described the experimental values very well. From the reaction rates obtained the kinetic constants were calculated and compared with the ones obtained from the initial rate method. Good agreement could be achieved between the two methods supporting the suggested mechanism. Copyright 1999 John Wiley & Sons, Inc.

Cloning and characterization of the gene for the thermostable xylanase XynA from Thermomyces lanuginosus.

A thermostable xylanase from the filamentous fungus Thermomyces lanuginosus (DSM 5826) was purified. This enzyme has an apparent molecular weight of 24-26 kDa as determined by SDS polyacrylamide gel electrophoresis. cDNA and genomic DNA fragments coding for this enzyme were cloned and sequenced. The cDNA contains an open reading frame encoding a polypeptide of 225 amino acids and was functionally expressed in E. coli as a LacZ fusion protein. Comparison of the cDNA sequence with the genomic DNA sequence showed that the xylanase was encoded by two exons interrupted by an intron of 106 bp. Comparison of the deduced amino acid sequence to other published xylanases revealed high homology to xylanases of the family G glycanases.

Esterase and lipase activity in Jatropha curcas L. seeds.

Two new esterases (JEA and JEB) and a lipase (JL) were extracted from the seeds of Jatropha curas L. Lipase activity was only found during germination of the seeds and increased to a maximum after 4 days of germination. All enzymes were found to be most active in the alkaline range at around pH 8 and the purified (fractionated precipitation with ethanol and gel filtration) esterases were very stable at high temperatures. The molecular weight (SDS-PAGE) of both esterases was determined to be 21.6-23.5 kDa (JEA) and 30.2 kDa (JEB) and the isoelectric point was 5.7-6.1 for esterase JEA and 9.0 for esterase JEB. Most ions caused a negative influence on the activity of both esterases. Using p-nitrophenyl butyrate as a substrate JEA showed a K(m) of 0.02 mM and a v(max) of 0.26 micromol mg(-1) min(-1). Under the same conditions JEB showed a K(m) of 0.07 mM and a v(max) of 0.24 micromol mg(-1) min(-1). Both esterases hydrolyzed tributyrin, nitrophenyl esters up to a chain length of =C4 and naphtylesters up to a chain length =C6. In transesterification reactions, JL was found to be most active at very low water activities (0.2) and in high water activities, the lipase hydrolysed triglycerides into conversions above 80%. The lipase hydrolysed both short chain and long chain triglycerides at about the same rate but was inactive on alpha-methylbenzyl acetate. JL is a potentially useful biocatalyst in the hydrolysis of triglycerides in organic solvents.

Peptide analysis as amino alcohols by gas chromatography-mass spectrometry. Application to hyperoligopeptiduria. Detection of Gly-3Hyp-4Hyp and Gly-Pro-4Hyp-Gly.

A method for the qualitative analysis of oligopeptides in human urine in cases of peptiduria is described. After sample precleaning on a strongly acidic ion exchanger, the trifluoroacetyl/methyl esters were formed and the peptide derivatives were transformed into trifluoroethyl oligoamino alcohols according to Nau and Biemann. It was found that oligoamino alcohols could be isolated selectively on a weakly acidic ion exchanger. The O-trimethylsilylated trifluoroethyl oligoamino alcohols were separated on a SE-30 glass capillary column and analyzed by computer-assisted gas chromatography-mass spectrometry. In order to increase specificity and to facilitate mass spectrometric interpretation, aliquots of the sample were reduced separately with lithium-aluminium deuteride and hydride. Each peptide gave a pair of derivatives with characteristic mass differences of the ions, namely 2 mass units per reduced oxo group (deuterium-hydrogen-labelling of oxo groups by reduction). Correct identification is assumed only if both mass spectral patterns fit the theory. Sample volumes of 5--100 ml of urine are needed. About six samples can be derivatized per week. Three cases with suspected peptiduria were investigated and the following peptides were found: Gly-Pro-4Hyp-Gly; Gly-Pro-4Hyp; Gly-Hyp-Hyp (postulated isomer Gly-3Hyp-4Hyp); Pro-4Hyp and Gly-Pro. With exception of the tetrapeptide, these compounds could be detected also in the urine of a healthy child.

Phototherapy in the treatment of depression in the terminally ill.

Research in affective disorders has shown that there is a clear link between mood and light exposure, and that exposure to bright wide-spectrum light (phototherapy) may be an effective antidepressant treatment in some clinical situations. Cancer patients, especially those in the terminal phase of illness, have a high incidence of depression. Furthermore, their mobility is often severely reduced, resulting in little exposure to direct sunlight. We report the use of phototherapy in three terminally ill patients to alleviate symptoms of depression.

Experimental method for the in vitro testing of the initial stability of cementless hip prostheses.

Micromotions at the interface between bone and prosthesis are believed to induce bone resorption and ultimately lead to loosening of the implant. Thus the initial stability achieved by a hip prosthesis is an important factor for the long-term function of the implant. Knowing the biological consequences of the mechanical conditions, it appears to be mandatory to measure the extent of these three-dimensional movements. An in vitro dynamic method for measurement of the micromotion of the femoral component of hip prostheses has been developed. Tests in cemented prostheses have confirmed that the use of cement reduces sinkage and rotation manyfold and have yielded reference values for stability. Comparison with two types of cementless prostheses has shown that certain cementless implants may achieve stability comparable to cemented ones in some load directions.

Transoral laser surgery of supraglottic cancer: follow-up of 141 patients.

OBJECTIVE: To determine the role of transoral laser resection of supraglottic carcinomas. DESIGN: Retrospective unicenter study of the oncologic results of transoral carbon dioxide laser microsurgery for supraglottic carcinomas performed between February 1979 and December 1993. Median follow-up was 37 months. SETTING: University hospital academic tertiary referral center. PATIENTS: We reviewed the medical records of 141 patients (a consecutive sample of 131 men and 10 women; mean age, 60 years) with histologically proven supraglottic carcinomas undergoing transoral laser surgery, possibly in combination with neck dissection or radiotherapy. Stage distribution of patients was as follows: stage I, 23.4%; stage II, 25.5%; stage III, 16.3%; and stage IV, 34.8% (according to the Union Internationale Contre le Cancer staging system). MAIN OUTCOME MEASURES: Recurrence-free survival rates and local and regional recurrence rates. RESULTS: Five-year recurrence-free survival rates were as follows: the whole case load, 65.7%; stage I, 85.0%; stage II, 62.6%; stage III, 74.2%; and stage IV, 45.3%, according to the Union Internationale Contre le Cancer staging system. The local and regional recurrence rates were 16.3% and 9.9%, respectively. CONCLUSIONS: The oncologic results of transoral carbon dioxide laser surgery are satisfying if clean surgical margins (R0 resection) can be reached. In patients in whom tumor-free margins are not achieved (R1 and R2 resection) and transoral revision is not possible, transcervical procedures (partial or total laryngectomy) should be performed. The indication for transoral supraglottic laryngectomy in T3 lesions should be considered with restraint.

Stent-angioplasty of an anastomotic stenosis of the pulmonary artery after lung transplantation.

Anastomotic stenosis of the pulmonary artery after lung transplantation is a rare complication, which commonly necessitates surgical correction. Transesophageal Doppler sonography and pulmonary arteriogram are standard diagnostic means for visualization of venous and arterial anastomoses. Balloon dilatation combined with implantation of a vascular endoprosthesis was successfully used for treatment of severe anastomotic stenosis of the pulmonary artery after lung transplantation.

Transglycosylation reactions with a crude culture filtrate from Thermoascus aurantiacus.

Some characteristics of regioselectivity and acceptor tolerance in transglycosylation reactions, catalysed by a crude culture filtrate from Thermoascus aurantiacus, were examined by employing methanol and monosaccharides as acceptors. When beta-D-mannopyranosyl fluoride was employed as the donor, the anomeric configuration of the newly formed bond was found to depend on the structure of the acceptor used.

Simultaneous detection of different glycosidase activities by 19F NMR spectroscopy.

A fast method for the simultaneous detection of different glycosidolytic activities in commercially available enzyme preparations and crude culture filtrates was found in using, as substrate, a mixture of different glycosyl fluorides and 19F NMR spectroscopy as a screening technique. Accompanying studies regarding the hydrolytic stability of these fluorides in various buffer systems, as well as conditions of their long-term storage, were carried out. A simple procedure for the preparation of beta-D-mannopyranosyl fluoride in gram quantities is given.

[Transthoracic excisional biopsy of focal pulmonary lesions]. / Transthorakale Schneidebiopsie fokaler Lungenläsionen.

The results of percutaneous, fluoroscopically-guided cutting biopsies of focal pulmonary lesions in 126 patients were evaluated retrospectively. In 90% of malignant lesions an exact diagnosis could be made from the material obtained. In 40% of the malignant lesions, histological examination was possible, in addition to cytology. In 87% of these, there was agreement between histology and cytology. Of the cases coming to surgery, 84% of the biopsies proved correct. Specificity was 100%. Multiple punctures were necessary in only 13%. Significant complications occurred in 5%. The cutting biopsy technique has the advantage of producing more biopsy material suitable for histology.

[Surgically treated thoracic aortic dissection. The angiographic follow-up of the perfusion relations]. / Operativ versorgte thorakale Aortendissektionen. Angiographische Verlaufskontrolle der Perfusionsverhältnisse.

Control angiography in arterial DSA technique was performed in 27 patients after operative treatment of acute aortic dissection (17 patients with type A dissection) respectively chronic aortic dissection (9 patients with type A dissection/1 patient with type B dissection). The mean interval between surgery and angiography was 59 months. All patients were free from symptoms due to organ complications or redissection. Persistent patency of a false lumen was observed in 40.7% (52.9% after operative treatment of an acute dissection; 20% after operative treatment of a chronic dissection). In all cases with a persistent false lumen the dissection originated at the distal anastomosis. In all patients the beginning of the dissection and the perfusion of the supra-aortal, visceral and iliac vessels whether by the true or false lumen could be shown. In 54.5% the Tr. brachiocephalic trunk was involved in the dissection. In 45.5% the left renal artery was solely perfused by the false lumen. Angiography in arterial DSA technique is evidently a valuable technique to document the beginning and extension of a dissection, sufficiency of the aortic valve, re-entries of the dissection, perfusion of the aortal branches, and the flow in both channels.