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Biomedical subjects

D Kaiser

Publications and source records attributed to D Kaiser.

At least 199 records · Page 11Linked to original sources
PubMed1983

[A 3-component basic diet in the therapy of severe protracted diarrhea].

The protracted diarrhea of young infants with failure to thrive is a clinically defined severe illness. Starting from acute enteritis it will lead to a vicious circle of malnutrition, malabsorption and food intolerance. 17 infants have been treated with a special diet of the three components: 1. oligopeptides (lact-albumin enzymatic hydrolysate); 2. long-chain triglycerides; and 3. Maltodextrin 5 (corn hydrolysate). These components are mixed according to the individual clinical state and intestinal tolerance. Trace elements, minerals and vitamins are added. Our diet has proven a great help in reducing and even replacing parenteral nutrition.

Chronic Disease↗
PubMed1982

Fruiting body morphogenesis in submerged cultures of Myxococcus xanthus.

Induced by starvation, the development of fruiting bodies by Myxococcus xanthus on glass and plastic surfaces under a layer of liquid was followed microscopically. Calcium ions and a neutral pH were required for development of a Myxococcus strain that grew dispersed in liquid culture. Initially asymmetric aggregates later became round, and sporulation followed aggregation.

Calcium↗
PubMed1982

Induction of coordinated movement of Myxococcus xanthus cells.

Rhythmically advancing waves of cells, called ripples, arise spontaneously during the aggregation of Myxococcus xanthus into fruiting bodies. Extracts prepared by washing rippling cells contain a substance that will induce quiescent cells to ripple. Three lines of evidence indicate that murein (peptidoglycan) is the ripple-inducing substance in the extracts. First, ripple-inducing activity is associated with the cell envelope of sonically disrupted M. xanthus cells. Second, whole cells, cell extracts, or purified murein from a variety of different bacteria are capable of inducing ripples. In contrast, extracts prepared from Methanobacterium spp. which contain pseudomurein instead of typical bacterial murein fail to induce ripples. Third, four components of M. xanthus murein, N-acetylglucosamine, N-acetylmuramic acid, diaminopimelate, and D-alanine, are able to induce ripples. Ripples produced by aggregating cells have a wavelength of 45 micrometers and a maximum velocity of 2 micrometers/min. Both of the multigene systems that control gliding motility appear to be required for rippling, and all known mutations at the spoC locus eliminate both rippling and sporulation.

Acetylglucosamine↗
PubMed1982

Murein components rescue developmental sporulation of Myxococcus xanthus.

Murein (peptidoglycan) components are able to rescue sporulation in certain sporulation-defective mutants of Myxococcus xanthus. N-Acetylglucosamine, N-acetylmuramic acid, diaminopimelic acid, and D-alanine each increase the number of spores produced by SpoC mutants. When all four components are included they have a synergistic effect, raising the number of spores produced by SpoC mutants to the wild-type level. Murein-rescued spores are resistant to heat and sonic oscillation and germinate when plated on a nutrient-rich medium. They appear to be identical to fruiting body spores in their ultrastructure, in their protein composition, and in their resistance to boiling sodium dodecyl sulfate. Murein rescue of sporulation, like fruiting body sporulation, requires high cell density, a low nutrient level, and a solid surface.

Acetylglucosamine↗
PubMed1981

Nucleoside requirements for the in vitro growth of bovine aortic endothelial cells.

The nutritional needs of cultured fetal bovine aortic endothelial cells were studied with regard to their nucleotide metabolism. When Medium 199 containing calf serum was supplemented with up to 5 microgram/ml of the deoxyribo- or ribonucleosides found in DNA or RNA, the rate of endothelial cell growth increased. The effect was entirely attributable to the pyrimidine nucleosides. The combination of deoxythymidine and deoxycytidine was much more effective than either deoxyribonucleoside used alone or than the combination of uridine and cytidine. Addition of deoxythymidine and deoxycytidine (each at 1 microgram/ml) to the medium supported the growth of endothelial cell cultures from initially sparse populations (ca. 50 cells/cm2), even at low concentrations (1%) of fetal bovine serum. The pyrimidine deoxyribonucleosides on their own were unable to stimulate cell growth; other bonafide growth stimulatory factors, such as those present in serum, serum dialysates, or retinal extracts, were needed in the medium to signal the initiation of DNA synthesis and cell replication. The significance of these findings with respect to improving cell performance under in vitro conditions and controlling endothelial cell growth in vivo are discussed.

Animals↗
PubMed1981

Introduction of transposon Tn5 into Myxococcus for analysis of developmental and other nonselectable mutants.

The transposon Tn5, which carries a gene for kanamycin resistance, can be introduced into Myxococcus xanthus, an organism that undergoes a primitive cycle of development, from Escherichia coli by the specialized transducing phage P1::Tn5. Tn5 DNA sequences, but no P1 sequences, are found in the stable kanamycin-resistant transductants. Tn5 transposes from P1 to many different chromosomal sites in Myxococcus. In each independent transductant of Myxococcus examined, the Tn5 element is found in a different DNA fragment produced by cleaving cell DNA with a restriction endonuclease. Moreover, different Tn5 insertions have been found linked to the first 20 different genetic sites tested. Once inserted into the Myxococcus chromosome, Tn5 remains fixed in position during growth and when transferred to another strain by generalized transduction. To analyze developmental or other mutants that have no selectable phenotype themselves, a general method has been devised, and tested, for the systematic isolation of a Tn5 insertion near any arbitrary locus.

Journal Article↗
PubMed1981

[Propafenon-induced cholestatic liver injury--a further example for allergic drug hepatitis (author's transl)].

In the course of cholestatic liver injury after propafenonhydrochloride medication, a high increase of the glutamatedehydrogenase up to the twenty fold of the normal range was followed by a marked raise of SGOT and SGPT. Cholestatic enzymes like gamma-glutamyl transpeptidase and alkaline phosphatase reached their maxima a week later. Within two weeks the hepatic cell enzymes and within four weeks the cholestatic enzymes have returned spontaneously to normal.

Adrenergic beta-Antagonists↗
PubMed1980

Accumulation of guanosine tetraphosphate and guanosine pentaphosphate in Myxococcus xanthus during starvation and myxospore formation.

Cultures of Myxococcus xanthus develop multicellular fruiting bodies when starved for carbon and nitrogen sources on an agar surface. Under these conditions of severe starvation, cultures rapidly accumulated a compound identified as guanosine tetraphosphate by chromatographic migration of the compound and of its major acid and alkali breakdown products. The accumulation of guanosine tetraphosphate was reduced in the presence of tetracycline, indicating that it may be synthesized by mechanisms similar to those of Escherichia coli. The guanosine tetraphosphate level was also reduced in starved cultures of a mutant unable to fruit normally, although it has been determined whether the defect in guanosine tetraphosphate accumulation is responsible for the inability to fruit. Induction of spores by glycerol addition led to transient increases in both guanosine tetraphosphate and guanosine pentaphosphate at a stage following most cell shortening, but before spores had acquired full refractility.

Adenosine Triphosphate↗
PubMed1980

Guanosine pentaphosphate and guanosine tetraphosphate accumulation and induction of Myxococcus xanthus fruiting body development.

Development of multicellular fruiting bodies of Myxococcus xanthus can be induced by limitation of any of a number of different classes of amino acids. Investigated were amino acids that wild-type strains of M. xanthus are unable to synthesize (isoleucine, leucine, and valine), can synthesize at a low rate (phenylalanine), or can normally synthesize at an adequate rate (tryptophan and serine). In general, gradual rather than abrupt starvation for an essential amino acid was required for the induction of fruiting. Perhaps gradual starvation in general minimizes antagonism between amino acids present in the medium, as was documented for valine starvation. The previously reported induction of fruiting by a high concentration of threonine was shown to be specifically reversed by lysine. Threonine addition may starve cells for lysine by feedback inhibition of aspartokinase activity. Starvation for carbon-energy sources or inorganic phosphate also induced fruiting. As in other bacteria, amino acid starvation of M. xanthus leads to increases in cellular guanosine polyphosphate, usually consisting of large increases in the amount of guanosine pentaphosphate with smaller increases in the level of guanosine tetraphosphate. Guanosine polyphosphate accumulation is thus shown to be correlated with nutritional conditions that induce fruiting, and therefore may serve as an intracellular signal to trigger cells to end vegetative growth and initiate fruiting body development.

Amino Acids↗
PubMed1980

Purine-containing compounds, including cyclic adenosine 3',5'-monophosphate, induce fruiting of Myxococcus xanthus by nutritional imbalance.

Induction of Myxococcus xanthus fruiting by a number of different purine-containing compounds, including cyclic adenosine 3',5'-monophosphate, is defective in a mutant resistant to 2,6-diaminopurine. Furthermore, the purine-induced fruiting of wild-type cultures is uniquely blocked by a low concentration of added glycine. These results imply that different purine-containing compounds induce fruiting through a single mechanism involving nutritional imbalance.

Adenine↗