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V Lehmann

Publications and source records attributed to V Lehmann.

At least 19 recordsLinked to original sources
PubMed1992

Cross-reacting serum opsonins in patients with meningococcal disease.

We have examined the opsonic activity of sera from patients with Neisseria meningitidis (B:15:P1.16) infections against different meningococcal strains, using flow cytometry and luminol-enhanced chemiluminescence. A marked increase in the phagocytosis of ethanol-fixed meningococcal strains of different serogroups, serotypes, and serosubtypes was demonstrated in the presence of convalescence sera compared with acute sera. Convalescence sera also caused a significant increase of leukocyte oxidative metabolism during phagocytosis, as measured by luminol-enhanced chemiluminescence. The sera contained a broad range of opsonins cross-reacting with serogroup A, B, C, W-135, and Y meningococci of different serotypes and serosubtypes, indicating that the cross-reacting opsonins recognized surface epitopes other than those determined by current serotyping schemes.

Adolescent↗
PubMed1992

Monocyte phagocytosis of opsonized Neisseria meningitidis serogroup B.

The chemiluminescence (CL) was examined when peripheral blood monocytes were incubated with opsonized Neisseria meningitidis, serogroup B, serotype 15:P1.16 or serotype 2a:P1.2. The monocytes were separated from a mononuclear cell suspension by an immunomagnetic negative selection technique using magnetic polystyrene microspheres coated with monoclonal antibodies specific for T and B lymphocytes. More than 90% of the lymphocytes were removed, yielding a suspension containing 93% monocytes. Optimal sensitivity for phagocytosis was obtained using 1% serum (10 microliters), 72 bacteria per monocyte cell, and 7.5 min opsonization and incubation time during continuous agitation at 37 degrees C. The CL was amplified by lucigenin. Preliminary experiments suggest that convalescent sera from patients with group B meningococcal disease induced increased CL responses compared to acute sera. Sera from volunteers immunized with an outer membrane complex vaccine from serogroup B, serotype 15:P1.16 or 2a:P1.2 meningococci also induced increased CL activity compared to preimmune sera. No such response was shown when a group B capsular polysaccharide vaccine was given. This response pattern was also demonstrated by a flow cytometric phagocytosis technique (FCM). Internalization of meningococci by monocytes was demonstrated by a FCM quenching technique and by transmission electron microscopy. CL and FCM represent rapid and reproducible methods for the measurement of opsonophagocytosis of meningococci by monocytes and may be performed with minute amounts of sera.

Adult↗
PubMed1979

Intrahepatic pressures measured during laparoscopy.

Intrahepatic pressure measured during laparoscopy were all correlated to occluded hepatic vein pressures and thereby to the portal vein pressures. Assessment of the intrahepatic pressures increases the diagnostic yield of laparoscopy, and should be used whenever it is important to quantitate the pressure in the portal circulation.

Hepatic Veins↗
PubMed1978

The acceptor for polar head groups of the lipid A component of Salmonella lipopolysaccharides.

We describe here experiments which determine at which stage in the lipid A biosynthesis the polar head groups 4-aminoarabinose, phosphorylethanolamine and 3-deoxy-D-manno-octulosonic acid are transferred to the diphosphorylated glucosamine backbone of the lipid A structure. Use was made of a conditional lethal mutant of Salmonella typhimurium (Ts1) which is defective in the synthesis of 3-deoxy-D-manno-octulosonic acid 8-phosphate and accumulates under nonpermissive conditions an underacylated lipid A intermediate [Lehmann, Rupprecht and Osborn (1977) Eur. J. Biochem. 76, 41-49]. Pulse-chase experiments, including a detailed analysis of radioactive pulse and chase products, demonstrated that this underacylated compound is a key intermediate in the lipid A synthesis. It can serve as direct acceptor for the incorporation of the polar head groups 4-aminoarabinose, phosphorylethanolamine and 3-deoxy-D-manno-octulosonic acid. On the basis of these findings some steps in the sequence of reactions involved in the lipid A biosynthesis are proposed.

Acetylglucosamine↗
PubMed1978

[The effect of sexual steroids on the isometric contraction of the isolated rat diaphragm (author's transl)].

The influence of estradiolbenzoate, hydroprogesteroncapronate and pregnancy on the mechanical reaction of the directly and indirectly stimulated nerve-diaphragm preparation has been the subject of this investigation. Rats were ovario-ectomized and the hormone preparations were injected subcutaneously. After a lapse of 9 days the test preparation was made. 1. Estrogen and the estrogen-gestagen combination have a similar effect on the isometric contraction of the transversely striated muscle. The times of rising and relaxation were prolonged after indirect and direct stimulation. The contraction amplitude had not altered compared to the control group. 2. Gestagens and the hormone situation of pregnancy entail, independent of the kind of stimulation, a decrease of the tension progress and the speed of the tension increase. The gestagen-treated animals underwent a shortened contraction process. These findings enable us to comment on the different efficiencies of women during various cycle phases and during pregnancy.

Animals↗
PubMed1978

Chemical structure and biological activities of lipid A's from various bacterial families.

The endotoxic principle of lipopolysaccharides (LPS) is localized in their lipid A component. Biological effects of LPS on, for instance, body temperature, blood pressure, and blood picture, are also induced by free lipid A. In contrast to the great variability of the 0-specific chains, the chemical structure of lipid A is much more constant. It is common for Salmonella and similar for other genera of the Enterobacteriaceae. Recently, a number of lipid A's have been recognized that exhibited distinct structural features compared with Enterobacteriaceae. These lipid A's were found to be also distinct with regard to some of their biological properties.

Carbohydrates↗
PubMed1978

[Animal experiments on the prevention of peritoneal adhesions (author's transl)].

Several possibilities for the prevention of adhesions were checked in animal experiments. In rats adhesions were produced by a standardized operative procedure. For the prevention of adhesions an artificial ascites with normal saline solution or Dextran was tried. To maintain ascites an intraperitoneal catheter was left in place for the first three post-operative days and refilled. The proteolytic effect of Chymotrypsin, the proteinase inhibitor Trasylol and of Glucocorticoids was investigated. All three drugs showed a definite therapeutic effect. In 45-50% of the rats adhesions were prevented. A combination of Trasylol, Glucocorticoids and Dextran prevented adhesions in 65% of the animals. When the ascites was maintained for four days 80% of the animals remained free of adhesions.

Animals↗
PubMed1978

[Enzyme values in the serum of newborn blood in relation to the course of parturition (author's transl)].

In 43 newborn, the enzyme activities of LDH, GOT, GLDH, and GPT in the umbilical cord blood, as well as 24 hours post partum was measured. Two groups were formed: 1. Newborn without decelerations during the course of parturition, and 2. Newborn with decelerations in the cardiotocogram. The oxygen partial pressure and the acid-base status in the umbilical cord blood, did not differ significantly in both groups. LDH, GOT and GLDH activities were significantly higher 24 hours post partum in the group of newborn with decelerations, than in the control group. The increase in GLDH by 75% was particularly remarkable. This GLDH increase seems to suggest an increased incidence of liver cell necroses, which must be interpreted as a result of the hypoxic conditions sub partu. A significant correlation between the magnitude of the deceleration areas and the extent of GLDH activities can be established. The correlation between duration of parturition and GLDH activity is likewise significant.

Alanine Transaminase↗
PubMed1977

A 31P-nuclear-magnetic-resonance study of the phosphate groups in lipopolysaccharide and lipid A from Salmonella.

Untreated and partially deacylated lipopolysaccharides from various P- and P+ strains of Salmonella were studied with 31P nuclear magnetic resonance spectroscopy and by conventional analytical methods. The spectral signals were assigned to various phosphate groups in the lipid A moiety and in the oligosaccharide part. A signal at +2.3 ppm could be assigned to a phosphodiester linkage formed between 4-amino-4-deoxyl-L-arabinose linked via the glycosidic hydroxyl group to the 4'-phosphate group of the glucosamine disaccharide in the lipid A moiety. A strong pyrophosphate signal at +11 ppm in P- strains was identified as a pyrophosphoryl ethanolamine group at the glycosidic end of this glucosamine disaccharide unit. No evidence was found for phosphodiester or pyrophosphodiester bonds crosslinking lipopolysaccharide 'subunits'. A revised version of the lipid A structure of Salmonella is presented. By a combination of 31P nuclear magnetic resonance spectroscopy data and conventional analytical methods the extent to which the lipopolysaccharides are substituted by various phosphate groups on the lipid A and the oligosaccharide moiety could be estimated. It was thus shown that substantial heterogeneity, leading to several molecular species of lipopolysaccharides is caused by addition or omission of certain groups. Since changes in substitution were found to be dependent on the growth conditions, it is thought possible that the overall negative surface charge of Salmonella can be modified by addition or omission of neutralising amino groups from ethanolamine and/or 4-amino-4-deoxy-L-arabinose, and can thus be adapted to the environment.

Carbohydrates↗
PubMed1977

Isolation of mutants conditionally blocked in the biosynthesis of the 3-deoxy-D-manno-octulosonic-acid--lipid-A part of lipopolysaccharides derived from Salmonella typhimurium.

A procedure is described for the selection of conditional 3-deoxy-D-manno-octulosonic-acid--Lipid A mutants which depends on temperature sensitivity for both synthesis of complete lipopolysaccharide and for growth. Using this procedure new types of mutants were isolated which cease growth and accumulate lipid A precursors following a shift to nonpermissive temperatures. All precursor molecules differ in their charge as judged by DEAE-cellulose chromatography. While they all contain glucosamine, phosphate and 3-hydroxymyristic acid, they lack detectable 3-deoxy-D-manno-octulosonic acid (dOclA) as well as the nonhydroxylated fatty acids of the complete lipid A structure. Three mutants proved to be conditionally defective in dOclA metabolism, whereas one seems to be blocked at a relatively early step in lipid A synthesis. The phenotypes of all these mutants appear to be due to single mutations by reversion analysis and by characterization of the temperature-resistant revertants. Studies of these mutants may shed light on the essential role of the complete dOclA--lipid A part of lipopolysaccharides in membrane function.

Aldehyde-Lyases↗