PubMed Health⌕ Search

Biomedical subjects

W Kaca

Publications and source records attributed to W Kaca.

At least 55 records · Page 3Linked to original sources
PubMed1996

Inhibition of mouse liver cytochrome P-450 by gram-negative bacteria lipopolysaccharides.

The ability of bacterial endotoxins, of different origin, to modify the level of mouse liver cytochrome P-450 was investigated. Endotoxins, (lipopolysaccharides, LPSs) were isolated from Proteus, Escherichia, Salmonella, Bacteroides and Coxiella strains. The most potent inhibitor of cytochrome P-450 activity was S. typhi 0101 LPS, which at a dose of 1 microgram/mouse reduced the cytochrome P-450 activity to 59%. E. coli O55:B5, S. typhimurium, P. mirabilis O3, and C. burnetii LPSs, at dose 10 micrograms/mouse, decrease cytochrome P-450 level from 56 to 69%. B. ovatus LPS significantly suppressed the expression of cytochrome P-450 only at the highest dose used-100 micrograms/mouse. The comparison of inhibitory activity of P. mirabilis complete, S and R types of LPSs indicate that lipid A portion of LPSs are sufficient to decrease the cytochrome P-450 level. However, the core oligosaccharide of LPS significantly enhance that inhibition. The isolated O-specific polysaccharide part of P. mirabilis O3 LPS did not decrease cytochrome P-450 level. The comparison of biological activity of Proteus LPSs, tested by chromogenic Limulus amebocyte lysate (LAL) test, demonstrated the enhancement effect of O-polysaccharide part of tested LPSs.

Animals↗
PubMed1996

Studies of antibiotic resistance of rough and smooth Proteus mirabilis strains and influence of polymyxin E on their lipopolysaccharide composition.

The influence of type of bacterial culture media on antibiotic resistance of Proteus mirabilis R and S forms, was tested. P. mirabilis S1959 (S form), R45 and R110 strains (Re and Ra mutant, respectively) cultivated in media supplemented with 10% heat inactivated bovine serum were resistant to ampicillin, amoxicillin, nalidixic acid and nitroxoline. Proteus strains cultivated in media without serum were sensitive to these antibacterial agents. The presence of serum did not change the polymyxin E (colistin) resistance of there Proteus strains tested. The effects of the presence of colistin (1000 U/ml) in culture media on Proteus lipopolysaccharide composition was studied. The content of uronic acids and phosphate residues in lipopolysaccharides isolated from bacteria cultivated in the presence of colistin (LPS-col), were lower than in control LPSs. The contents of 4-amino-4-deoxy-L-arabinose decreases in S1959 LPS-col, increases in R110 LPS-col and remains unchanged in R45 LPS-col. These results indicate that the presence of colistin in cultivation media exerts an influence on the contents of charged components of LPSs isolated from polymyxin E-resistant Proteus R and S strains.

Amino Sugars↗
PubMed1996

[Structure of O-specific polysaccharide from Proteus mirabilis O10, containing a new component of O-antigens--L-altruronic acid].

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Proteus mirabilis O10 and studied after full acid hydrolysis and carboxyl reduction by 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected heteronuclear 1H,13C multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY). It was found that the polysaccharide contains 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, D-galacturonic acid, and L-altruronic acid, and the following structure of the branched tetrasaccharide repeating unit of the polysaccharide was established: [sequence: see text]

Carbohydrate Conformation↗
PubMed1996

Comparison of serological reactions of Rickettsiae-infected patients and rabbit anti-Proteus OX antibodies with Proteus OX2, OX19 and OXK lipopolysaccharides.

The reactivity of anti-Rickettsiae human antibodies with Proteus OX cells is used as a presumptive rickettsial diseases diagnostic test Weil-Felix reaction. In presented studies we compare the reactivity of human anti-Rickettsiae and rabbit anti-Proteus antibodies with series of Proteus OX2, OX19 and OXK lipopolysaccharides (LPS). Polyclonal rabbit anti-OX2, anti-OX19 and anti-OXK sera reacted only with the homologous LPS--OX2, OX19 and OXK, respectively. The antibodies of Japanese spotted fever patients were less specific and reacted with OX2 as well as OX19 LPS. The antibodies of scrub typhus patients recognized Proteus OXK LPS, only. The serological reactions of O-antigen of P. mirabilis S1959 indicated that this, previously serologically not classified, strain may belong to the OXK group. Bacteria, used in the studies, came from the American, Japanese and European strain collections. The series of OX2, OX19 and OXK LPS, isolated from these Proteus strains, presented pattern of electrophoretic mobility and serological reactivities specific for each of OX-group types.

Animals↗
PubMed1996

[Neutrophil activation by bacterial endotoxins].

The endotoxin (lipopolysaccharide, LPS), major component of Gram-negative bacteria cell wall, activate numerous types of cells, neutrophils included. The chemical compositions of polysaccharide (O-specific polysaccharide and core oligosaccharide) and hydrophobic lipid A parts of LPS are presented. The bindings of LPSs to neutrophils resulted in signal transduction and neutrophils activation. Neutrophils, under LPS stimulation, generate oxygen radicals, nitric oxide and other components of inflammatory processes.

Endotoxins↗
PubMed1996

[Use of the Limulus test (LAL) to detect endotoxins].

Limulus amebocyte lysate (LAL) test is commonly used for the detection of trace amounts of endotoxins (lipopolysaccharides, LPS). The mechanisms, LPS structural requirements and limitations of LAL tests are presented.

Endotoxins↗
PubMed1995

Effects of bacterial endotoxin on human cross-linked and native hemoglobins.

Previous investigations have demonstrated that hemoglobin (Hb) is a binding protein for bacterial endotoxin (lipopolysaccharide, LPS) and that the structure and biological activity of LPS are altered in the presence of Hb. In the present study, the influence of LPS on the structure of native human HbA0 and covalently cross-linked Hb (alpha alpha Hb) was studied by analyzing the absorption and circular dichroic spectra of Hb in the wavelength region of 200-650 nm. Incubation of oxyHb with each of several LPSs resulted in a decrease in the intensity of the major Soret band at 414 nm with a shift in the maximum peak to 410 nm, decreases in the intensities of the major visible region peaks at 541 and 577 nm, and the appearance of increased absorbance in the visible region in the range of 630 nm. The resultant spectra are characteristic of methemoglobin formation. These spectral changes were time-dependent and LPS-concentration-dependent. Production of methemoglobin was prominent with chemically modified, partially deacetylated rough LPS, and was observed to a lesser extent both with native, complete rough and with native smooth LPSs. The influence of LPS on the absorption spectrum of methemoglobin also was directly tested. The conversion of methemoglobin to hemichrome in the presence of LPS was demonstrated and was shown to be reversible. Analysis of circular dichroic spectra of Hb demonstrated LPS-induced spectral changes in the visible and Soret regions consistent with the production of a substantial quantity of metHb, but did not demonstrate any alteration in the far-UV region (210-240 nm). Moreover, Hb oxygen affinity was only slightly altered after incubation with any of several LPSs. In conclusion, analyses of absorption and circular dichroic spectra reveal the potential of LPS to produce a facilitated oxidation of both alpha alpha-cross-linked human Hb and native human HbA0, without substantial changes in the secondary structure of the globin.

Bacterial Toxins↗
PubMed1995

The structure and serological specificity of Proteus mirabilis O43 O antigen.

On the basis of sugar analysis and NMR spectroscopy, including selective spin-decoupling, one-dimensional NOE, two-dimensional homonuclear and 13C,1H-heteronuclear correlation spectroscopy, the following structure of the acidic O-specific polysaccharide of Proteus mirabilis O43 was established: -->4)-alpha-D-GalpA-(1-->3)-alpha-D-GalpA-(1-->3)-alpha-D-Gl cpNAc-(1-->4)-alpha - D-Glcp-(1-->, where GalA is galacturonic acid and Galp is galactopyranose. No serological cross-reactivity was observed between lipopolysaccharides of P. mirabilis O43 and other studied Proteus strains, except for P. mirabilis O10. The O-specific polysaccharide of P. mirabilis O43 was serologically active in precipitation and inhibition tests but the activity was lost after periodate oxidation. These data suggest that the O43 specificity is determined by a wide epitope with the immunodominant role of 4-substituted D-Glc or/and D-GalA, which are destroyed by periodate oxidation.

Antibodies, Bacterial↗
PubMed1995

Activation of complement by human hemoglobin and by mixtures of hemoglobin and bacterial endotoxin.

Purified human hemoglobin is being developed as an alternative to transfusions of homologous erythrocytes. However, toxicity associated with infusion of hemoglobin has limited the development of this resuscitation fluid. Some observed toxicities, including activation of the complement cascade, have been associated with contamination of hemoglobin solutions by bacterial endotoxin. Recent studies have demonstrated complex formation between hemoglobin and endotoxin, and have documented a resultant increase in the ability of endotoxin to activate coagulation, stimulate tissue factor production by human peripheral blood mononuclear cells, and stimulate tissue factor activity and protein synthesis in cultured human endothelial cells. The process of hemoglobin enhancement of endotoxin toxicity suggests a possible mechanism by which the consequences of endotoxin contamination of hemoglobin solutions, including complement activation, could be magnified. Therefore, we studied the potential of hemoglobin to either fix complement directly, or modify the ability of endotoxin to fix complement. Human crosslinked and native hemoglobins, at concentrations between 0.2 mg/ml and 3 mg/ml, were shown to fix complement. Complement fixation by hemoglobin was identical in normal human serum or in factor B-depleted serum, suggesting that fixation occurred via the classical pathway of complement activation. Complement fixation then was examined with a battery of smooth and rough endotoxins tested in the absence and presence of hemoglobin. Addition of hemoglobin to a solution of a rough Salmonella endotoxin partial structure, from which a single fatty acid had been hydrolyzed from the lipid A portion of the macromolecule, resulted in decreased efficiency of complement fixation. However, addition of hemoglobin had little or no effect on the intrinsic complement fixing abilities of eight other smooth endotoxins, rough endotoxins, or endotoxin partial structures. Our results demonstrated the ability of hemoglobin to fix complement at hemoglobin concentrations which would be achieved during infusion for resuscitation, but failed to demonstrate a reproducible effect of hemoglobin on the activation of complement by endotoxin.

Bacterial Toxins↗
PubMed1995

Structure and epitope characterisation of the O-specific polysaccharide of Proteus mirabilis O28 containing amides of D-galacturonic acid with L-serine and L-lysine.

The O-specific polysaccharide of Proteus mirabilis O28 was found to contain D-galactose, D-galacturonic acid (GalA), 2-acetamido-2-deoxy-D-glucose, L-serine, L-lysine, and O-acetyl groups in molar ratios 1:2:1:1:1:1, the amino acids being linked via their alpha-amino group to the carboxyl group of GalA. The polysaccharide was studied using 1H- and 13C-NMR spectroscopy, including selective spin-decoupling, one-dimensional total correlation spectroscopy, two-dimensional homonuclear correlation spectroscopy (COSY), heteronuclear 13C,1H COSY, one-dimensional NOE, and two-dimensional rotating-frame NOE spectroscopy and partial acid hydrolysis followed by borohydride reduction, methylation, and GLC/MS analysis of the derived glycosyl alditols. The following structure of the repeating unit was established: [formula: see text] Epitope specificity of the P. mirabilis O28 polysaccharide was analysed using a homologous rabbit polyclonal antiserum in quantitative precipitation, passive immunohemolysis, and inhibition of passive immunohemolysis. Study with related synthetic glycopolymers (2-acrylamidoethyl glycosides of amides of alpha-D-GalA with amino acids copolymerised with acrylamide) showed the importance of D-GalA(L-Lys) for manifesting serological specificity of the O-antigen. Serological cross-reactions between P. mirabilis O28, S1959, and R14/S1959 (a transient-like form) are discussed.

Amides↗
PubMed1995

Structure and epitope specificity of the O-specific polysaccharide of Proteus penneri strain 12 (ATCC 33519) containing the amide of D-galacturonic acid with L-threonine.

O-specific polysaccharide was isolated from Proteus penneri strain 12 (ATCC 33519) lipopolysaccharide (LPS) and studied using NMR spectroscopy, including selective spin-decoupling, one-dimensional NOE, two-dimensional homonuclear correlation spectroscopy, 13C,1H heteronuclear correlation spectroscopy and chemical methods (O-deacetylation, Smith degradation, partial acid hydrolysis followed by borohydride reduction and methylation). The amide of D-galacturonic acid with L-threonine [D-GalA(L-Thr)] was identified as a constituent of the polysaccharide and the following structure of the tetrasaccharide repeating unit was established: [formula: see text] where the degree of O-acetylation at either position varies over 20-40%. Serological study with LPS, its degradation products and related synthetic glycoconjugates (2-acrylamidoethyl glycosides of amides of alpha-D-GalA with L-amino acids copolymerised with acrylamide) showed that D-GalA(L-Thr) plays an important role in manifesting the serological specificity of the P. penneri 12 O-antigen. Serological cross reactions between LPSs of P. penneri 12 and Proteus mirabilis S1959, R14/S1959 (transient-like form), O23 and O28 are discussed.

Amides↗
PubMed1994

Hemoglobin, a newly recognized lipopolysaccharide (LPS)-binding protein that enhances LPS biological activity.

Cell-free hemoglobin (Hb) is a purified preparation of human hemoglobin that is being developed as a resuscitation fluid. In vivo administration of hemoglobin has resulted in significant toxicity, due in part to contamination with bacterial endotoxin (lipopolysaccharide (LPS)). To better understand this toxicity, we have studied the interaction between Hb and LPS. Mixtures of each of three different Hb preparations (cross-linked alpha alpha Hb, cross-linked carbon monoxy-alpha alpha HbCO, and non-cross-linked (native) HbAo) and LPS (Escherichia coli O26:B6 or Proteus mirabilis S1959) were examined by several independent methods for evidence of Hb.LPS complex formation. Binding assays in microtiter plates demonstrated saturable binding of LPS to immobilized Hb, with a kD of 3.1 x 10(-8) M. Binding of LPS to Hb also was demonstrated wiht a radiolabeled LPS photoaffinity probe. Ultrafiltration of Hb/LPS mixtures by 300- and 100-kDa cut-off membranes showed that the majority of LPS in these mixtures (87-97 and 64-72%, respectively) was detected in the filtrates, in contrast to the lack of filterability of LPS in the absence of Hb. Density centrifugation demonstrated that LPS co-migrated with each of the three Hbs, whereas unbound LPS had a distinctly greater sedimentation velocity than Hb or Hb.LPS complexes. Nondenaturing polyacrylamide gel electrophoresis demonstrated that in the presence of Hb, LPS migrated into the gel and co-electrophoresed with Hb, whereas LPS alone did not appreciably enter the gel. Finally, precipitation by ethanol of each of the three Hb preparations was increased in the presence of LPS compared with precipitation in the absence of LPS. Interaction of LPS with each of the three Hb preparations was also associated with altered biological activity of LPS, as shown by enhancement of LPS activation of Limulus amebocyte lysate. Therefore, our data provide several lines of independent evidence for Hb-LPS complex formation and indicated that LPS exhibited altered physical characteristics and enhanced biological activity in the presence of Hb.

Acute-Phase Proteins↗
PubMed1994

Toxicity of hemoglobin solutions: hemoglobin is a lipopolysaccharide (LPS) binding protein which enhances LPS biological activity.

Administration of alpha alpha-crosslinked stroma-free hemoglobin (SFH) as a cell-free resuscitation fluid is associated with multiple organ toxicities. Many of these toxicities are characteristic of the pathophysiological effects of bacterial endotoxins (lipopolysaccharide, LPS). To better understand the potential role of LPS in the observed in vivo toxicities of SFH, we examined mixtures of SFH and E. coli LPS for evidence of LPS-SFH complex formation. LPS-SFH complexes were demonstrated by three techniques: ultrafiltration through 300 kDa cut-off membranes, which distinguished LPS in complexes (87-89% < 300 kDa) from LPS alone (90% > 300 kDa); density centrifugation through 5% sucrose, which distinguished denser LPS alone from LPS-SFH complexes; and precipitation by 67% ethanol, which demonstrated 2-3 fold increased precipitability of complexes compared to SFH alone. Interaction of LPS with SFH was also associated with markedly increased biological activity of LPS, as manifested by enhancement of LPS activation of Limulus amebocyte lysate (LAL), increased release of human mononuclear cell tissue factor, and enhanced production of cultured human endothelial cell tissue factor. These results demonstrated that hemoglobin can serve as an endotoxin binding protein, and that this interaction results in the alteration of several LPS physical characteristics and enhancement of LPS biological activities.

Acute-Phase Proteins↗
PubMed1994

Hemoglobin: a newly recognized binding protein for bacterial endotoxins (LPS).

Administration of purified hemoglobin (Hb) as a cell-free resuscitation fluid is associated with multiple organ toxicities. Many of these toxicities are characteristic of the pathophysiological effects of bacterial endotoxins (lipopolysaccharide, LPS). To better understand the potential role of LPS in the observed in vivo toxicities of Hb, we examined mixtures of Hb and LPS for evidence of LPS-Hb complex formation. LPS-Hb complexes were demonstrated by three techniques: ultrafiltration through 300 kDa cut-off membranes, which distinguished LPS in complexes (87-89% < 300 kDa) from LPS alone (90% > 300 kDa); density centrifugation through sucrose, which distinguished denser LPS alone from LPS-Hb complexes; and precipitation by 67% ethanol, which demonstrated 2-3 fold increased precipitability of Hb in complexes compared to Hb alone. Interaction of LPS with Hb was also associated with markedly increased biological activity of LPS, as manifested by enhancement of LPS activation of Limulus amebocyte lysate (LAL), increased release of human mononuclear cell tissue factor, and enhanced production of human endothelial cell tissue factor. These results demonstrated that hemoglobin can serve as an endotoxin binding protein, and that this interaction results in the alteration of several of the physical characteristics of LPS and enhancement of the biological activities of LPS. These findings suggest that a mechanism for the toxicity of infused Hb in vivo may involve potentiation of the biological effects of LPS. In addition, these observations suggest a mechanism by which LPS-related morbidity during sepsis could be enhanced by erythrocyte hemolysis.

Acute-Phase Proteins↗
PubMed1993

[Structural and immunologic studies of Proteus mirabilis 033 O-specific polysaccharide].

O-specific polysaccharide was obtained by mild acid degradation of P. mirabilis 033 lipopolysaccharide (LPS). It was found to contain N-acetyl-D-glucosamine, D-glucuronic acid and N-acetyl-L-fucosamine in a ratio 1:1:1. On the basis of the data obtained from 13C-NMR and methylation analysis, the following structure of repeating unit was established: [formula: see text] Selective removal of the D-GlcA significantly decreased reactivity of 033 O-specific polysaccharide with homologous antiserum. This component was plays an immunodominant role. Cross reactivity between anti-033 serum and disaccharide alfa-L-FucNAc-beta-D-GlcNAc containing P. vulgaris 023 and S. arizonae 059 O-specific polysaccharides was also observed.

Antigens, Bacterial↗
PubMed1991

Structural and immunochemical studies of O-specific polysaccharide of Proteus vulgaris 5/43 belonging to OX19 group (O-variants).

O-specific polysaccharide was obtained on mild acid degradation of lipopolysaccharide of Proteus vulgaris 5/43 belonging to OX19 (O-variants). It was found to contain D-glucose, 2-acetamido-2-deoxy-D-glucose, and 2-acetamido-2,6-dideoxy-L-glucose (QuiNAc, N-acetyl-L-quinovosamine) in the ratio of about 1:2:1, the last-named sugar being rather uncommon for bacterial antigens. A computer-assisted 13C-NMR-based analysis, methylation analysis, and selective cleavage with anhydrous hydrogen fluoride and dilute hydrochloric acid were applied for structural elucidation of the polysaccharide and the following structure was established:----2)-beta-D-Glcp-(1----6)-alpha-D-GlcpNAc-(1----3)- alpha-L-QuipNAc-(1----3)-beta-D-GlcpNAc-(1----. Serological studies of the O-antigen and oligosaccharides derived therefrom revealed the importance of the trisaccharide fragment beta-D-Glcp-(1----6)-alpha-D-GlcpNAc-(1----3)-alpha-L- QuipNAc in manifesting the antigenic specificity. Serological cross-reactions were demonstrated between lipopolysaccharides of P. vulgaris 5/43, 8/44, and OX19 strains.

Acetylglucosamine↗