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Biomedical subjects

H Mayer

Publications and source records attributed to H Mayer.

At least 199 records · Page 11Linked to original sources
PubMed1988

Chemical and immunochemical studies on lipopolysaccharides of Coxiella burnetii phase I and phase II.

Lipopolysaccharides of Coxiella burnetii phase I and II were comparatively investigated by chemical and immunochemical methods. LPS of phase I (LPS I) and phase II cells (LPS II) show no serological cross reaction, indicating that the serological determinants of LPS II are masked in LPS I. Chemical analysis of LPS I and II show that phase I and II cells can be considered as S and R forms of Coxiella burnetii. The structure of LPS II has recently been elucidated and shows a dimannosylated core of an alpha(1,3)-linked heptose-disaccharide which is attached to a "KDO-like" substance. In enterobacterial core-types, alpha(1,3)-linked heptose-disaccharide is also part of the inner core structure, although the heptose occurring in enterobacterial R cores is the L-glycero-D-manno-heptose. In Coxiella burnetii we have only the rare D-glycero-D-manno-heptose which is the biosynthetic precursor of the former and is in many enteric LPS, present only in addition to L-glycero-D-mannoheptose. In these R-cores, it is occupying mostly terminal positions (Radziejewska-Lebrecht et al., 1981) and is absent from the main chain. The complete structure of LPS I is not yet available, but some important points could recently be clarified. The immunodominant sugars in LPS I are C-3-branched sugars, 6-deoxy-3-C-methyl-L-gulose (L-virenose) and 3-C-(hydroxymethyl)-L-lyxose (dihydro-hydroxy-L-streptose). These two sugars have not been found so far in other lipopolysaccharides and the latter one not previously in any other natural product. Their identification is based on GLC-MS comparison with authentic and synthetic compounds. Both branched sugars (and in addition part of the mannose) are the terminal sugars in LPS I. Sites of attachment of phase I-specific sugars to the LPS II-core are: the 3-position of a branched heptose and, presumably, the 4-position of a terminal D-mannose. The extreme acid-lability of the linkages of both branched sugars was investigated in detail and is caused by the nature of the branched sugars (deoxyhexose with bulky axial substituents; pentofuranose with axial OH-groups). No information is so far available on the (penultimate) sugars to which the branched sugars are linked, but methylation analyses with LPS I, and with the recently described I/CR mutant, which is selectively lacking the virenopyranose, are presently performed.

Carbohydrate Conformation↗
PubMed1988

Progressive isoinertial lifting evaluation. I. A standardized protocol and normative database.

Dynamic tests of trunk strength and lifting capacity have become more popular in recent years, offering certain advantages over static isometric tests in measuring patient progress in functional restoration programs for spinal disorders. However, equipment for performing such tests is expensive to buy, complex to run, and requires technical expertise and clinical volume unavailable in most physician offices. In this study, a new dynamic test known as Progressive Isoinertial Lifting Evaluation (PILE) is described, which draws upon prior psychophysical and isoinertial methods. An industrial sample of 61 male and 31 female incumbent workers were tested using the PILE, and a variety of anthropometric normalizing factors were evaluated. The isolation of an "Adjusted Weight" (AW) normalizing factor is documented, after which normative data are presented for male and female workers utilizing lumbar (0-30 inches) and cervical (30-54 inches) dynamic protocols.

Adult↗
PubMed1988

Structural relationship between the polyagglutinable antigen and the core polysaccharide of Pseudomonas aeruginosa.

It has been observed that each strain of the Pseudomonas aeruginosa species harbours the so-called polyagglutinable antigen (PA). Some strains may produce it in a form which is linked to the core moiety of lipopolysaccharide (LPS) and this type of PA can thus be detected by passive haemagglutination using the isolated LPS as coating antigen. Other strains synthesize PA exclusively in a free form, which is also coextractable with LPS, its presence can, however, be demonstrated by the haemagglutination inhibition test. From a polyagglutinable strain of P. aeruginosa an R-type LPS was isolated having the core-linked PA. This LPS preparation was highly immunogenic with regard to its PA moiety. The core-bound PA seems to exert an immunosuppression on the core region, hence, the polyagglutinable strains isolated from cystic fibrosis patients only engender anti-PA antibodies, whereas antibodies against both, side chain and core region of LPS, are not engendered. The mucoid exopolysaccharide also contains the PA which could possibly play an important role in the patient by protecting P. aeruginosa cells against anti-PA antibodies.

Antibodies, Bacterial↗
PubMed1988

Antigenicity and immunogenicity of the polyagglutinable antigen of Pseudomonas aeruginosa.

Pseudomonas aeruginosa strains isolated from cystic fibrosis patients agglutinate in antisera against anti-polyagglutinable antigen (PA). Anti-PA antibodies were formed in rabbits when immunization was carried out with bacteria possessing core-bound PA, independently of whether the strains were of S or R phenotype. For bacterial agglutination with anti-PA antibodies two prerequisites are essential: the bacterial cell must be of R phenotype and must possess the core-linked PA. In contrast, the PA in the isolated LPS's can be demonstrated in passive haemagglutination for both (S or R) phenotypes, provided the PA is core-linked. Two PA forms have been recognized, one found only in P. aeruginosa species, both in free and bound form. The other one is shared by all members of Pseudomonas genus but is present only in a free, unbound form.

Antigens, Bacterial↗
PubMed1988

ECA, the enterobacterial common antigen.

Enterobacterial common antigen (ECA) is a family-specific surface antigen shared by all members of the Enterobacteriaceae and is restricted to this family. It is found in freshly isolated wild-type strains as well as in laboratory strains like Escherichia coli K-12. The family specificity of ECA can be used for taxonomic and diagnostic purposes. ECA is located in the outer leaflet of the outer membrane. It is a glycophospholipid built up by an aminosugar heteropolymer linked to an L-glycerophosphatidyl residue. In a few rough mutants, in addition, the sugar chain can be bound to the complete lipopolysaccharide (LPS) core. Recently, for Shigella sonnei a lipid-free cyclic form of ECA was reported. The genetical determination of ECA is closely related to that of lipopolysaccharide. For biosynthesis of ECA and LPS partly the same sugar precursors and the same carrier lipid is used.

Animals↗
PubMed1988

Characterization of an Escherichia coli rff mutant defective in transfer of N-acetylmannosaminuronic acid (ManNAcA) from UDP-ManNAcA to a lipid-linked intermediate involved in enterobacterial common antigen synthesis.

The rff genes of Salmonella typhimurium include structural genes for enzymes involved in the conversion of UDP N-acetyl-D-glucosamine (UDP-GlcNAc) to UDP N-acetyl-D-mannosaminuronic acid (UDP-ManNAcA), the donor of ManNAcA residues in enterobacterial common antigen (ECA) synthesis. An rff mutation (rff-726) of Escherichia coli has been described (U. Meier and H. Mayer, J. Bacteriol. 163:756-762, 1985) that abolished ECA synthesis but which did not affect the synthesis of UDP-ManNAcA or any other components of ECA. The nature of the enzymatic defect resulting from the rff-726 lesion was investigated in the present study. The in vitro synthesis of GlcNAc-pyrophosphorylundecaprenol (lipid I), an early intermediate in ECA synthesis, was demonstrated by using membranes prepared from a mutant of E. coli possessing the rff-726 lesion. However, in vitro synthesis of the next lipid-linked intermediate in the biosynthetic sequence, ManNAcA-GlcNAc-pyrophosphorylundecaprenol (lipid II), was severely impaired. Transduction of wild-type rff genes into the mutant restored the ability to synthesize both lipid II and ECA as determined by in vitro assay and Western blot (immunoblot) analyses done with anti-ECA monoclonal antibody, respectively. Our results are consistent with the conclusion that the rff-726 mutation is located in the structural gene for the transferase that catalyzes the transfer of ManNAcA from UDP-ManNAcA to lipid I.

Antigens, Bacterial↗
PubMed1988

Lipopolysaccharides of Thiocystis violacea, Thiocapsa pfennigii, and Chromatium tepidum, species of the family Chromatiaceae.

The lipopolysaccharides (LPS) of three species of purple sulfur bacteria (Chromatiaceae), Thiocystis violacea, Thiocapsa pfennigii, and the moderately thermophilic bacterium Chromatium tepidum, were isolated. The LPS of Thiocystis violacea and Chromatium tepidum contained typical O-specific sugars, indicating O-chains. Long O-chains were confirmed for these species by sodium deoxycholate gel electrophoresis of their LPS. Thiocapsa pfennigii, however, had short or no O-chains. The core region of the LPS of all three species comprised D-glycero-D-mannoheptose as the only heptose and 2-keto-3-deoxyoctonate. The lipid A, obtained from the LPS by mild acid hydrolysis, contained glucosamine as the main amino sugar. Amide-bound 3-hydroxymyristic acid was the only hydroxy fatty acid. The main ester-bound fatty acid in all lipid A fractions was 12:0. Mannose and small amounts of 2,3-diamino-2,3-dideoxy-D-glucose were common constituents of the lipid A of the three Chromatiaceae species investigated. All lipid A fractions were essentially free of phosphate.

Chromatiaceae↗
PubMed1988

[The progress of a fibrinolytic therapy with streptokinase, urokinase and warfarin in a thoroughbred with intermittent lameness with special reference to resonance thrombography].

A thoroughbred horse, suffering from intermittent lameness was treated with streptokinase, urokinase and warfarin. The appearing fibrinolytic changes in coagulation were exhibited in a resonance thrombogram. In attendant coagulation studies fibrinogen- and fibrin-degradation products were demonstrated. The stallion does not show any lameness since the end of the treatment and is standing in a breeding station since March 1988.

Animals↗
PubMed1987

A prospective two-year study of functional restoration in industrial low back injury. An objective assessment procedure.

One hundred sixteen consecutive patients entered a functional restoration treatment program for chronic low back pain and were compared with 72 patients not treated. A two-year follow-up survey reached more than 85% of both groups; its findings were compared with earlier results of a five-month and one-year follow-up. Analysis demonstrated that 87% of the treatment group was actively working after two years, as compared with only 41% of the nontreatment comparison group. Moreover, about twice as many of the comparison group patients had additional spine surgery relative to the treatment group. The comparison group continued with an approximately five times higher rate of patient visits to health professionals in the second year as the treatment group. Also, treatment group reinjury rates were no higher than those expected in the general population, while nontreatment subjects had a higher incidence of reinjury. Finally, a small treatment "dropout" group did poorest of all, with results in almost all areas even worse than those of the comparison group patients.

Adult↗
PubMed1987

Comparison of enterobacterial common antigen from different species by serological techniques.

Enterobacterial common antigen (ECA) was isolated from a number of selected species (including Salmonella montevideo, Shigella sonnei and Plesiomonas shigelloides) using the extraction method described by Männel and Mayer [Eur. J. Biochem. 86, 361-370 (1978)]. ECA of all these species behaved identically in enzyme-linked immunosorption assay (ELISA) and in its inhibition using monoclonal anti-ECA antibodies. Immunoblotting showed a ladder-like pattern of at least 20 bands for all preparations tested. ECA modified at its lipid moiety (e.g. by phospholipases A2 and D or by mild acid hydrolysis) lost its coating capacity leaving, however, the serological reactivity as detected by inhibition assays intact. In contrast, reduction of the carboxylic groups of 2-acetamido-2-deoxy-D-mannopyranosyluronic acid destroyed the serological reactivity. Deacylated ECA was also not detectable in immunoblotting. Chemical reacylation restored the reactivity of deacylated ECA in ELISA and in immunoblot and thus proved the essential function of fatty acids for the physicochemical properties of the molecule. 2-Acetamido-2-deoxy-D-glucopyranose was identified as the reducing end of the ECA sugar chain after splitting off the lipid moiety by phospholipase D.

Acylation↗
PubMed1987

Chemical characterization of enterobacterial common antigen isolated from Plesiomonas shigelloides ATCC 14029.

Serologically characterized samples of enterobacterial common antigen (ECA) from Plesiomonas shigelloides, Salmonella montevideo and Shigella sonnei were investigated by chemical methods including methylation and NMR techniques. All showed the same sugar composition and contained a lipid moiety with palmitic acid as main fatty acid and with a phosphodiester group. Additional enzymatic studies, reported in the preceding paper, provided evidence that the lipid moiety is an L-glycerophosphatidyl residue attached via a phosphodiester linkage to C-1 of GlcNAc as the reducing end of the ECA sugar chain. ECA of P. shigelloides showed the best-resolved 13C-NMR spectra, especially after the removal of non-stoichiometric O-acetyl groups at C-6 of GlcNAc of the ECA repeating unit and of the lipid moiety by mild acid hydrolysis (0.01 M HCl, 100 degrees C, 10 min). Subsequent 13C-NMR studies were therefore carried out with the mild-acid-treated ECA of P. shigelloides which allowed a tentative assignment of all resonances of the ECA repeating unit. 13C-NMR spectra of Salmonella and Shigella ECA were essentially the same as those obtained with Plesiomonas ECA. The same trisaccharide repeating unit was encountered as demonstrated previously in the cyclic form of ECA isolated from S. sonnei by Dell et al. [Carbohydr. Res. 133, 95-104 (1984)]. Methylation analysis, however, afforded small amounts of terminal GlcNAc thus proving, in combination with the demonstration of the attached lipid moiety, an acyclic nature of ECA from P. shigelloides and from the two enterobacterial species. The question of whether the cyclic form co-exists in S. sonnei phase I and possibly in other enterobacterial species or, whether it had been formed during extraction as an artifact, has not yet been answered. The way in which ECA was isolated in our studies would preclude the presence of a non-amphiphilic (cyclic) polysaccharide. The finding that the sugar chain of ECA is attached to an L-glycerophosphatidyl residue is in full corroboration with serological, enzymatic and gel electrophoretic studies shown in the preceding paper and with the character of ECA as a surface antigen being anchored by hydrophobic interactions in the outer membrane of Enterobacteriaceae and P. shigelloides.

Antigens, Bacterial↗
PubMed1987

[Effect of diabetes mellitus on light scattering of the human lens].

Long-term changes in the light-scattering in clear lenses of diabetic patients were documented with the Scheimpflug camera. The initial cataract formations within defined layers of the lens were analyzed by standardized digital area densitometry. There was no statistically significant variation of the light-scattering between the individual layers. The results differ from other investigations based on the linear densitogram of the optical axis beam.

Cataract↗
PubMed1987

Characterization of a native polysaccharide hapten from Brucella melitensis.

The 13C nuclear magnetic resonance spectrum of Brucella melitensis native polysaccharide hapten proved to be very similar to that generated by the O-specific chain (PS) isolated from B. melitensis lipopolysaccharide; that is, to a linear polymer in which the repeating unit is composed of five N-formylperosaminyl residues, one of them being substituted at position C-3 and the other four at position C-2. The serological analysis suggests that the so-called A determinant is present solely in Brucella abortus PS, the M determinant is only in B. melitensis PS, and the extensive cross-reaction observed is due to a determinant shared by both polysaccharides.

Antigens, Bacterial↗
PubMed1987

Application of digital image analysis in cataract retroillumination photography.

The Stuttgart digital image analysis system for Scheimpflug photography can be applied without additional extension for pattern recording and densitometric measurements in retroillumination photographic techniques. A preliminary investigation with serial photographs in human cataract showed a large variation in the measured results. Standardisation of photographs taken by the retroillumination technique is not yet possible. For this reason, application of the retroillumination technique is not suitable at this time for clinical longitudinal studies.

Cataract↗