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Biomedical subjects

Z Szilágyi

Publications and source records attributed to Z Szilágyi.

11 recordsLinked to original sources
PubMed2000

Molecular dynamics simulation of metallothionein-drug complexes.

The intermolecular interactions of metallothionein with nitrogen mustard drugs were studied by molecular dynamics simulations. Previous laboratory experiments have defined selective alkylation of two cysteine residues, and selective binding was proposed to precede alkylation. The present study provides information about accessibility to cysteines based on evaluating the intermolecular energies and distances in the first few ps of dynamics simulations. A series of dynamics simulations was performed with three drug molecules positioned at the eight most solvent accessible cysteine residues of the dimeric form of the protein. Sites proximal to the sulfhydryl groups of Cys-33 and Cys-48 were found to be the most favorable for complexing the aziridinium forms of chlorambucil, melphalan, and mechlorethamine. The sites for preferential binding are in qualitative agreement with the sites of selective alkylation defined experimentally.

Binding Sites↗
PubMed1999

Proteinase inhibitors from desert locust, Schistocerca gregaria: engineering of both P(1) and P(1)' residues converts a potent chymotrypsin inhibitor to a potent trypsin inhibitor.

Two peptides, SGCI and SGTI, that inhibited chymotrypsin and trypsin, respectively, were isolated from the haemolymph of Schistocerca gregaria. Their primary structures were found to be identical with SGP-2 and SGP-1, two of a series of peptides isolated from ovaries of the same species (A. Hamdaoui et al., FEBS Lett. 422 (1998) 74-78). All these peptides are composed of 35-36 amino acid residues and contain three homologous disulfide bridges. The residues imparting specificity to SGCI and SGTI were identified as Leu-30 and Arg-29, respectively. The peptides were synthesised by solid-phase peptide synthesis, and the synthetic ones displayed the same inhibition as the natural forms: SGCI is a strong inhibitor of chymotrypsin (K(i) = 6.2 x 10(-12) M), and SGTI is a rather weak inhibitor of trypsin (K(i) = 2.1 x 10(-7) M). The replacement of P(1) then P(1)' residues of SGCI with trypsin-specific residues increased affinity towards trypsin 3600- and 1100-fold, respectively, thus SGCI was converted to a strong trypsin inhibitor (K(i) = 5.0 x 10(-12) M) that retained some inhibitory affinity towards chymotrypsin (K(i) = 3.5 x 10(-8) M). The documented role of both P(1) and P(1)' highlights the importance of S(1)'P(1)' interactions in enzyme-inhibitor complexes.

Amino Acid Sequence↗
PubMed1999

Genetics, physiology and cytology of yeast-mycelial dimorphism in fission yeasts.

The order Schizosaccharomycetales contains a dimorphic and two yeast species. Sch. japonicus can form both yeast cells and mycelium, depending on the substrate and the culturing conditions. Sch. pombe is a strictly unicellular organism, but it can be forced to form mycelial cell chains by inactivating members of the sep gene family. The mutations in most of the sep genes confer pleitropic phenotypes indicating functional involvement in MAP-kinase-mediated signalling pathways. Two of them were found to encode transcription factor homologues of other eukaryotes.

Cell Polarity↗
PubMed1997

[Mandibular fracture in an infant].

Maxillofacial fractures under 10 years of age are uncommon, with an occurrence of 7.3%. Isolated fractures of the mandible are even more rare, due to the fact that in young children the mandible is relatively small and resilient. Some authors suggest that the occurrence of this form of fracture is about 1-5%. Different methods have been described for treatment of fractures off the mandible in children. In the therapy since the introduction of titanium mini plates the trend has been to select surgical repositioning followed by osteosynthesis. This paper describes the management of a 7-month old boy with isolated mandibular fracture, using this method to avoid the damage of the tooth germs. This particular case raises the issue of child abuse, which is on the increase in Hungary as well. To find a kind of solution would be not only a task of dentists but also of society in general.

Age Factors↗
PubMed1995

[Computer tomography in implantology].

During the planning of implantation the CT method helps in determining the location of the implant and aids in choosing the right implant. It provides the following measurable information about the jaw-bones: height and width; exact location of bone deficiencies; the orovestibular shape of the alveolar process; the course of the mandibular canal; the location of the mental foramen; the location and size of the canalis incisivus; the area of the nasal cavity and the maxillary sinus; the quality of the bones and the relationship between cortical and spongious bone. In comparison to the X-ray examinations possession of these informations increase significantly the safety of planning before surgery.

Dental Implantation↗
PubMed1994

[Correlation between meteorologic factors and periostitis of dental origin in Debrecen].

Correlation between bioclimatical and meteorological factors is well documented. The aim of this study was to investigate the correlation between dental periostitis and meteorological fronts, cyclon and anticyclon. We found a positive, statistically significant correlation between occurrence of warm meteorological front, cyclon, anticyclon and prevalence of dental periostitis. It could have important implications in organizing the work of dental teams.

Climate↗
PubMed1992

[Free-end reconstruction by dento-osseous autotransplantation].

The authors describe an endosseal autotransplantation A tooth is extracted together with its parodontium and the surrounding bone. It is implanted into a different place where the bone had been prepared. Upper left unilateral free-end saddle cases were solved by removing the tooth No 24 into the place of No 27. A bridge was constructed after 6 weeks using the 23 as abutment. The metal-ceramic bridges have been used by the patients for 3 years without complaint.

Adult↗
PubMed1991

Two-dimensional echocardiographically guided pericardiocentesis in a horse with traumatic pericarditis.

Two-dimensional echocardiographic (2DE) examination was performed on a horse with clinical signs of pericardial effusion. Thickening of the pericardium, excess amount of pericardial fluid, elevation of the cardiac apex, and right ventricular compression, characteristic of cardiac tamponade, could be seen on 2DE recordings. Fibrinous pericarditis was suspected by observation of fibrinous strands in the pericardial fluid and epicardial fibrin deposits. Echocardiographically guided pericardiocentesis was performed, and 4 L of fluid was removed from the pericardial sac. Streptococcus zooepidemicus was isolated from the fluid. Pericardiocentesis was repeated for 3 days, and medication was administered. Despite temporary improvement in cardiac function, the horse's condition deteriorated gradually, and euthanasia was performed on the ninth day of hospitalization. Necropsy revealed chronic serofibrinous pericarditis of traumatic origin, attributable to an intercostal stab wound entering the pericardium and the apical portion of the myocardium.

Animals↗