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D Kaiser

Publications and source records attributed to D Kaiser.

At least 217 records · Page 12Linked to original sources
PubMed1979

Social gliding is correlated with the presence of pili in Myxococcus xanthus.

Myxococcus xanthus, an organism whose motility involves cell interactions, normally bears pili. Myxococcal pili are found only at cell poles, are less than 10 nm in diameter, and may be longer than a cell. Myxococcus has two basic patterns of cell movement, adventurous (A-motility) and social (S-motility). Pili are found to be completely correlated with the presence of S-motility. (The S-motility pattern has many groups of cells, almost no single cells, and is governed by a set of genes called system S.) On the other hand, A-motility is in dependent of piliation. (The A-motility pattern has many single, isolated cells and it is governed by a second set of genes called system A.) Electron microscopic examination of more than 40 genetically different strains shows that all A+S+ (wild-type) and A-S+ strains have pili, but A+S- and A-S- strains lack them. Mutations in four different loci belonging to system S were tested and were found to stop productions of pili: the loci sg1A, sg1B, sg1G, and tg1. When brought into contact with tg1+ cells, cells of a tg1- strain, which lack pili, become phenotypically S+, produce pili, and become S-motile. Both motility and the production of pili are transient when initiated in this way. Thus it appears that pili permit cells that are close to one another to move.

Fimbriae, Bacterial↗
PubMed1979

[Perioperative behavior of prostaglandin E2 (PGE2) and 13,14-dihydro-15-keto-PGF2 alpha (DHK-PGF2 alpha) in the serum in bronchial cancer].

The perioperative behaviour of PGE2 and DHK-PGF2 alpha was studied in peripheral blood of patients undergoing lung surgery. The measurement of prostaglandins was performed by RIA after an extraction procedure. Common control criteria were observed. In 39 patients blood sampling was performed preoperatively and 2 weeks postoperatively. PGE2 and DHK-PGF2 alpha were significantly elevated in 8 patients with lung cancer before the operation. Postoperatively the concentrations decreased; 2 weeks later, DHK-PGF2 alpha was still slightly increased, PGE2 had normalized. 9 patients suffering from tuberculosis had normal serum concentrations of PGE2 and DHK-PGF2 alpha before and after resection procedures. In 8 cases the resection of benign lung diseases did not cause any abnormal reactions. In 2 special groups blood sampling was performed the following way: in 4 cancer patients and 3 tuberculosis patients blood was collected preoperatively, 5 times in the first hour after lung resection and 1 day and 2 weeks after operation. It could be demonstrated that PGE2 and DHK-PGF2 alpha almost completely normalized within the first postoperative hour in cancer patients, whereas no significant alterations could be found in tuberculosis. After discussion of technical problems in the measurement of prostaglandins the alterations of PG concentrations after lung cancer resection are emphasized.

Bronchial Neoplasms↗
PubMed1979

[Pleural adhesions and deformation of the chest wall (author's transl)].

Deformation of the chest wall and pleural adhesions are some of the sequelae of chest trauma with fractures of ribs. If sufficiently extensive these lesions may result in restrictive disturbances of ventilation and partial respiratory insufficiency. In these cases marked improvement in function and perfusion can be obtained by decortication at an early stage. Follow-up examinations of 37 patients who had sustained fractures of more than 4 ribs revealed restrictive respiratory impairment in only three cases. Hypoxia was present in 11, but a causal connection with the trauma could be ascertained in only 4 persons. For assessing the extent of the lesions and the indications for decortication perfusion scanning is a "must", as it will show up pathological changes at a time when the gaseous exchange and lung function still appear normal. There seems to be no correlation between the radiological extent of the adhesions or the deformation of the thorax and the extent of changes in lung function and blood gases.

Blood Gas Analysis↗
PubMed1978

Nutrition of Myxococcus xanthus, a fruiting myxobacterium.

The minimal requirements for vegetative growth of Myxococcus xanthus have been sought. Isoleucine, leucine, and valine were required, and vitamin B12 was needed for the synthesis of methionine. Pyruvate was an excellent energy source and an efficient source of cellular carbon. Acetate, aspartate, glutamate, and most tricarboxylic acid cycle intermediates could also be utilized, but were less efficient sources of carbon and energy than was pyruvate. Many mono- and disaccharides were tested, but, in agreement with earlier results, none served as carbon-energy sources. A minimal medium (A1) has been devised that includes the essential amino acids and vitamin B12, with pyruvate and aspartate as carbon-energy sources. In this medium, M. xanthus could propagate indefinitely, and on it vegetative cells formed colonies with greater than 75% efficiency; hence, it is likely that no organic cofactors other than those present in A1 are required in more than trace amounts.

Amino Acids↗
PubMed1977

[Screening of newborn infants in cystic fibrosis. Evaluation of a 4-year study in Switzerland].

The results of an evaluation over 4 years (1973-1976) of 16,620 BM-tests (Boehringer-Mannheim newborn screening for cystic fibrosis) at 8 hospitals in Switzerland are presented and the data from analysis of albumin, protein and alpha1-antitrypsin concentrations, and on trypsin-inhibitory capacity of the meconia are discussed. 99.5% of the tests were negative. Of the remaining 0.5% BM-positive tests, the diagnosis of cystic fibrosis required confirmation by sweat test and clinical course in 6 cases, or 0.04% of the total collective. The test was false-negative in 2 cases (0.012%), of which one had a primary pulmonary form of cystic fibrosis. The study shows that the BM-test, as screening test for cystic fibrosis, makes it possible to distinguish between "normal" and "suspect". By calculating the ratio albumin to alpha1-antitrypsin, it would be possible to verify the probability of a reliable diagnosis as early as a few days after birth. As before, however, it would be indispensable to confirm the diagnosis of cystic fibrosis by a sweat test with pilocarpin iontophoresis. By consistent screening in all obstetric and pediatric clinics it would be possible to improve early diagnosis still further.

Cystic Fibrosis↗
PubMed1977

Cell-to-cell stimulation of movement in nonmotile mutants of Myxococcus.

A large number of nonmotile mutants of the gliding bacterium Myxococcus xanthus have been isolated and partly characterized. About [unk] of these mutants are conditional mutants of a novel kind: mutant cells become transiently motile after contact with nonmutant cells or with cells of a different mutant type. These "stimulatable" mutants fall into five phenotypic classes (types B, C, D, E, and F). Most mutants are nonstimulatable (type A) and never become motile, but type A cells (and wild-type cells) can stimulate cells of any of the other five types. Stimulatable mutants of different types are capable of stimulating each other. For example, in a mixture of B and C cells, both become motile. Linkage analysis using a generalized transducing phage has shown that each of types B, C, D, E, and F corresponds to a single distinct genetic locus. Type A mutants, by contrast, belong to at least 17 different loci. Stimulation depends on close apposition of interacting cells, because stimulation does not occur when contact between cells is prevented. It is possible that the stimulatable mutants are defective in components of the gliding mechanism that can be exchanged between cells. Alternatively, they may be defective in a system of cell communication controlling the coordinated cell movements observed in Myxococcus.

Journal Article↗