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Biomedical subjects

J Zakrzewski

Publications and source records attributed to J Zakrzewski.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

IgA1 protease production by bacteria colonizing the upper respiratory tract.

Thirty-eight clinical isolates of Haemophilus influenzae and ten clinical isolates of Streptococcus pneumoniae were examined for IgA1 protease production. A suspension of surface material of each individual strain was incubated with human secretory IgA; IgA1 cleavage products were detected by SDS-PAGE and immunoblotting. The high incidence of IgA1 protease-positive strains (68.4% of the examined H. influenzae and 100% of the examined S. pneumoniae strains) confirms that IgA1 protease activity is a frequent characteristic of these two species. Yet the presence of this enzyme is, if at all, only a minor decisive factor for the induction of symptomatic infections of the upper respiratory tract by IgA1 protease-positive bacteria.

Bacterial Proteins↗
PubMedDate not supplied

Cyclopentadienyl iron dicarbonyl (eta 1-N-phthalimidato) complexes containing an isothiocyanate function: synthesis and application to protein side-chain selective labeling.

The two first transition metal carbonyl isothiocyanates were prepared in high yield within two steps from photolysis of CpFe(CO)2I and 3- or 4-aminophthalimide in the presence of diisopropylamine followed by reaction with thiophosgene/triethylamine. Their reaction with a model amino acid, i.e. beta-alanine, was performed and led to the expected thioureas. When reacted with bovine serum albumin in aqueous medium, conjugates bearing 6-10 iron-carbonyl fragments were obtained and characterized by Fourier transform infrared spectroscopy, thus demonstrating the usefulness of these reagents for the selective and covalent labeling of proteins.

Iron Compounds↗
PubMedDate not supplied

Synthesis of CpFe(CO)(L) complexes of hydantoin anions (Cp = eta5-C5H5, L = CO, PPh3), and the use of the 5,5-diphenylhydantoin anion complexes as tracers in the nonisotopic immunoassay CMIA of this antiepileptic drug.

As part of our ongoing development of the CMIA nonisotopic immunoassay method, in which the tracers are metal carbonyl complexes and detection is by Fourier transform infrared spectroscopy, we examined the potential use as tracers of the complexes CpFe(CO)2(5,5-diphenylhydantoin) 2d and CpFe(CO)(PPh3)(5, 5-diphenylhydantoin) 3. The present study involved the synthesis of a series of hydantoin complexes (2a-2d), in particular that of the derivative of 5,5-diphenylhydantoin 2d. The structure of 2d was confirmed by X-ray crystallography. The infrared analysis, establishing the position and intensity of the characteristic metal-carbonyl peaks of complexes 2d and 3 in the 1850-2200 cm-1 region, shows that measurement of the absorbance values of these characteristic peaks will permit quantitative analysis in the picomole range, the norm for routine use in immunoassay and thus suitable for use as CMIA tracers. Cross-reaction rates of these tracers with anti-DPH specific antibodies show that 2d and 3 are both recognized by anti-DPH antibodies (cross-reaction rates 43 and 20%, respectively). In developing a CMIA of DPH with these tracers, it was found that 3, with a single, intense band at 1977 cm-1, had very promising IR characteristics for use in multiassay CMIA, but probably owing to its relatively weak affinity for the antibodies, it was not possible to develop a CMIA for DPH using this tracer. Complex 2d, however, showed better recognition by the antibodies, and using this complex as a tracer, it was possible to develop a particularly sensitive monoassay of DPH by the CMIA method.

Anions↗
PubMedDate not supplied

Nasal mucosa in the iron deficient state. A clinical and electron-microscopic study.

Good results of iron therapy obtained in ozena patients with significantly lowered serum iron level encouraged studies on the pathogenesis of the disease. In electron microscopic examinations, special attention was paid to the considerable disintegration of connective-tissue stroma in the mucosa. In some connective-tissue cells ferruginous micelles were found in the mitochondrial matrix. Mitochondrial deposits may be a morphological expression of disturbed iron metabolism at subcellular levels.

Cytoplasm↗