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Biomedical subjects

K Kaczmarek

Publications and source records attributed to K Kaczmarek.

12 recordsLinked to original sources
PubMed2006

[Intermittent ciliary block as a result of haemodialysis].

We report the case of a patient who experienced recurrent elevations of intraocular pressure during haemodialysis. We measured a rise in intraocular pressure of 10-12 mmHg after dialysis. The lens showed intumescence, and a ciliary block was detected by means of Orbscan II. Within 6 h findings had normalized. Changes in serum osmolarity due to haemodialysis may result in fluid shifts between different compartments. Decrease of serum osmolarity during dialysis may lead to lens swelling and thus cause a ciliary block. This may end with regression of the lens swelling.

Aged↗
PubMed2005

[Differentiation between pupillary and ciliary block by means of the Orbscan II in a patient with angle block glaucoma].

BACKGROUND: A ciliary block is the rarer cause of angle block glaucoma. In order to choose the appropriate therapy, however, it is crucial to make the correct diagnosis. We report on a patient who suffered from recurrent increases of intraocular pressure while having renal dialysis. In his case the use of the Orbscan II made the differentiation between a pupillary and a ciliary block easier. CASE REPORT: In addition to basic ophthalmological examinations we performed a topographic analysis using Orbscan II before and after renal dialysis. Since intraocular pressure rise during renal dialysis had been proven, iridotomies on both eyes and an iridectomy on the left one had been performed before the patient was referred to us. In spite of these open shunts we measured an increase of intraocular pressure values of 10 to 12 mmHg directly after renal dialysis had been completed. The anterior chamber became shallower both at its centre and the periphery, thus its volume diminished analogously. Measurements by the Orbscan II showed that the lens swelled up and was displaced anteriorly as well, so that a ciliary block mechanism had to be assumed. CONCLUSIONS: Since the Orbscan II is capable of collecting topometric data of the cornea, anterior chamber and also lens, it is helpful in differentiating a pupillary from a ciliary block in angle block glaucoma.

Aged↗
PubMed2001

C(alpha)-hydroxymethyl methionine: synthesis, optical resolution and crystal structure of its (+)-N(alpha)-benzoyl derivative.

(R, S)-Methionine was transformed into C(alpha)-hydroxymethyl methionine by a route involving C(alpha)-hydroxymethylation of 2-phenyl-4-methylthioethyl-5-oxo-4,5-dihydro-1,3-oxazole. The absolute configuration of (-)-C(alpha)-hydroxymethyl methionine was elucidated to be (S) by chemical correlation with (S) (-)-C(alpha)-ethyl serine. Absolute structure determination (by single crystal X-ray diffraction) on N(alpha)-benzoyl-C(alpha)-hydroxymethyl methionine confirmed the (R)-configuration for the (+)-enantiomer. In addition, the X-ray diffraction analysis showed that the C(alpha,alpha)-disubstituted glycyl residue adopts the fully extended (C5) conformation.

Crystallography, X-Ray↗
PubMed2001

A novel cis-peptide bond motif inducing beta-turn type VI. The synthesis of enkephalin analogues modified with 4-aminopyroglutamic acid.

A new pathway leading to a mixture of four isomers of 4-aminopyroglutamic acid is described. Michael type addition of Z-deltaAla-OMe to enolates prepared from acylaminomalonates, followed by hydrolysis and decarboxylation give protected 4-aminopyroglutamic acid with the cis:trans ratio approximately 3:2. This mixture was incorporated into Leu-enkephalin (position 2-3). After separation of peptides it appeared that all analogues were essentially inactive in guinea pig ileum and mouse vas deferens bioassays.

Amino Acid Motifs↗
PubMed1992

Facilitated synthesis of peptaibols: alamethicin via enzymatic segment condensation.

We have used a combined chemical-enzymatic approach to facilitate the total synthesis of the 20-residue peptaibol, alamethicin. The 1-11 segment of alamethicin, having a C-terminal Gly, and the 12-20 segment, having an N-terminal Leu, were prepared by well-established chemical methods, and then coupled using papain to afford a 54% yield of alamethicin in straightforward fashion. In contrast to the reported chemical syntheses of alamethicin requiring side-chain protection at Glu,18 the papain-catalyzed coupling proceeded readily and selectively using a C-terminal segment having a free gamma-carboxyl group at this position. Several alamethicin partial sequences were obtained via enzymatic formation of the Gly11-Leu12 bond. The high efficiency of this route is illustrated by the enzymatic assembly of the 1-17 alamethicin fragment on a 400-mg scale in 62% yield. An alternative route to alamethicin through enzymatic formation of the Ala6-Gln7 bond was less successful because of a low yield in the final coupling.

Alamethicin↗
PubMedDate not supplied

Feature based fuzzy matching of 2D gel electrophoresis images.

Automatic alignment (matching) of two-dimensional gel electrophoresis images is of primary interest in the evolving field of proteomics. In the present study, feature-based matching techniques, in their classical and robust versions, are described, and an automatic method of fuzzy alignment (FA) is introduced. This method allows automatic matching of two gel images with different numbers of features with unknown correspondence. Performance of FA is tested on simulated and real data sets.

Automation↗
PubMedDate not supplied

Matching 2D gel electrophoresis images.

Automatic alignment (matching) of two-dimensional gel electrophoresis images is of primary interest in the field of proteomics. The proposed method of 2D gel image matching is based on fuzzy alignment of features, extracted from gels' images, and it allows both global and local interpolation of image grid, followed by brightness interpolation. Method performance is tested on simulated images and gel images available via the Internet databases.

Algorithms↗