Search PubMed⌕ Search

Biomedical subjects

J Janczak

Publications and source records attributed to J Janczak.

11 recordsLinked to original sources
PubMed2001

Bis(melaminium) sulfate dihydrate.

The crystals of a new melaminium salt, bis(2,4,6-triamino-1,3,5-triazin-1-ium) sulfate dihydrate, 2C3H7N6+*SO4(2-)*2H2O, are built up from monoprotonated melaminium(1+) residues, sulfate(2-) anions and water molecules. The SO4(2-) ion has a slightly distorted tetrahedral geometry. The melaminium residues are interconnected by N-H.N hydrogen bonds, forming chains. The chains of melaminium residues develop a three-dimensional network through multiple donor-acceptor hydrogen-bond interactions with sulfate anions and water molecules.

Journal Article↗
PubMed2001

Melaminium chloride hemihydrate.

The crystals of a new melaminium salt, 2,4,6-triamino-1,3,5-triazin-1-ium chloride hemihydrate, C(3)H(7)N(6)(+).Cl(-).0.5H(2)O, are built up from single-protonated melaminium residues, chloride anions and water molecules. The protonated melaminium cations lie on a twofold axis, while the chloride anions and water molecule lie on the m plane. The melaminium residues are interconnected by N-H...N hydrogen bonds, forming chains parallel to the (001) plane. The chains of melaminium residues form a three-dimensional network through hydrogen-bond interactions with chloride anions and water molecules.

Journal Article↗
PubMed2001

Iodo(phthalocyaninato)chromium(III).

A new chromium(III)-phthalocyanine complex with the formula [Cr(C(32)H(16)N(8))I], or CrPcI where Pc is phthalocyanate(2-), has been obtained by the reaction of pure Cr powder with phthalonitrile under a stream of iodine vapour. The five-coordinate Cr atom is bonded to the four isoindole N atoms of the phthalocyaninate(2-) ligand and to one apical iodine ligand, and has a square-pyramidal coordination geometry. The Cr(III) cation is significantly displaced [0.456 (2) A] from the N(4)-isoindole plane towards the I atom. The Cr-I bond is tilted 2.51 (4) degrees to the N(4)-isoindole plane.

Journal Article↗
PubMed2001

Melaminium bis(4-hydroxybenzenesulfonate) dihydrate.

The crystals of a new melaminium salt, 2,4,6-triamino-1,3,5-triazine-1,3-diium bis(4-hydroxybenzenesulfonate) dihydrate, C3H8N6(2+)*2C6H5O4S-*2H2O, are built up from doubly protonated melaminium(2+) residues, dissociated p-phenolsulfonate anions and water molecules. The doubly protonated melaminium dication lies on a twofold axis. The hydroxyl group of the p-hydroxybenzenesulfonate residue is roughly coplanar with the phenyl ring [dihedral angle 13 (2) degrees ]. A combination of ionic and donor-acceptor hydrogen-bond interactions link the melaminium and p-hydroxybenzenesulfonate residues and the water molecules to form a three-dimensional network.

Journal Article↗
PubMed2001

[Phthalocyaninato(2-)]antimony(III) chloride.

The title antimony(III) complex, [Sb(C32H16N8)]Cl or [SbPc]Cl (where Pc = C32H16N8(2-)), has been obtained from the reaction of pure powdered antimony with 1,2-dicyanobenzene under a stream of ICl vapour. The asymmetric unit of this complex consists of an [SbPc](+) cation and a Cl(-) anion. The phthalocyaninate residue [SbPc](+) is not planar. The Sb atom lies 1.057 (3) A from the plane defined by the four isoindole N atoms. A combination of ionic and donor-acceptor interactions links the [SbPc]Cl molecules to form centrosymmetric [(SbPc)Cl](2) pseudo-dimers in the crystal. The Sb-Cl distances in the pseudo-dimer are not equivalent [3.043 (2) and 3.201 (2) A]. The pseudo-dimers are weakly linked through Cl...H-C(benzo) interactions to form a three-dimensional network. As a result of these interactions, the four Sn-N(isoindole) bond lengths in the [SbPc](+) residue are not equivalent and the symmetry of the Sb-N core is only close to Cs.

Journal Article↗
PubMed2001

Melaminium phthalate.

The crystals of the new melaminium salt, 2,4,6-triamino-1,3,5-triazin-1-ium hydrogenphthalate, C3H7N6+.C8H5O4-, are built up from single protonated melaminium residues and single dissociated hydrogenphthalate(1-) anions. The protonated melaminium ring is almost planar. The best plane through the non-dissociated carboxyl group (COOH) of the hydrogenphthalate(1-) anion is inclined at an angle of 16.4 (2) degrees to the plane of the six-membered hydrogenphthalate ring, while the plane of the ionized COO- group is roughly perpendicular [84.2 (2) degrees ] to this plane. A combination of ionic and donor-acceptor hydrogen-bond interactions linking together the melaminium and hydrogenphthalate residues forms a three-dimensional network.

Journal Article↗
PubMed1997

A peptide derived from neutrophil inhibitory factor (NIF) blocks neutrophil adherence to endothelial cells.

OBJECTIVE AND DESIGN: Peptides derived from neutrophil inhibitory factor (NIF), a known antagonist of Mac-1, were evaluated as inhibitors of neutrophil adherence. MATERIAL: In vitro assays of adherence employed: 1) human polymorphonuclear cells (PMN), 2) human umbilical vein endothelial cells (HUVEC), and 3) CHO cells expressing ICAM-1 (CHO-ICAM cells). TREATMENT: Cells, pretreated with NIF-derived peptides (0.1-100 microM) for 10 minutes, were permitted to adhere for 20 min in the continued presence of peptide. METHODS: Cell-based assays: 1) PMN adherence to HUVEC, 2) PMN adhesion to immobilized human serum proteins, and 3) adherence of CHO-ICAM cells to immobilized Mac-1. RESULTS: A NIF-derived peptide of 29 amino acids blocked PMN adherence to HUVEC, but behaved somewhat differently than the parent NIF protein. NIF specifically antagonized Mac-1 dependent adherence, but the peptide blocked neutrophil adherence that was dependent upon both Mac-1 and LFA-1 integrins. CHO-ICAM adherence to Mac-1 was blocked by NIF, but not by the peptide. Binding studies with NIF and the peptide indicate that the molecules bind to different sites. CONCLUSIONS: A peptide derived from NIF blocks PMN adherence but, unlike NIF, the mechanism of action is not mediated by direct antagonism Mac-1.

Amino Acid Sequence↗
PubMed1989

[Value of Holter monitoring and the electrocardiographic exercise test in the diagnosis of silent ischemia after myocardial infarction].

In 75 patients 24-hour ecg monitoring value was compared with exercise test in diagnostics of postinfarction silent ischemia. Results compatibility of both comparing examinations was 79% with regard to only painless ischemia (p less than 0.001) and 91% to both estimated painless or painful episodes (p less than 0.001). Painless ischemia was observed during ecg Holter monitoring and exercise test respectively in 39% and 35% of examined patients (NS) and/or with the angina respectively in 44% and 53% (p less than 0.01). 24-hour ecg monitoring and exercise test are of a comparable value in diagnosis of postinfarction silent ischemia, whereas in diagnostics of jointly estimated painless or painful ischemia the exercise test is a more sensitive examination than ecg Holter monitoring.

Adult↗