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Biomedical subjects

S Geissler

Publications and source records attributed to S Geissler.

At least 19 recordsLinked to original sources
PubMed2000

Anorexia in rats infected with the nematode, Nippostrongylus brasiliensis: experimental manipulations.

Nippostrongylus brasiliensis induces a biphasic anorexia in laboratory rats, the first phase coincident with lung invasion (ca day 2) and the second when the worms mature in the intestine (ca day 8). Using the anthelminthic, mebendazole (MBZ), N. brasiliensis infections of the rat were eliminated between the first and second anorexic episodes. This intervention prevented the expression of the second phase of anorexia. Rats exposed to a second infection with N. brasiliensis, 3 weeks after the primary infection, exhibited only a first phase anorexic response which was not influenced by MBZ termination of the primary infection. The lower cumulative food intake and weight gain of all infected rats after 8 days of infection were accompanied by elevated plasma insulin and, in some individuals, by elevated plasma leptin, compared with uninfected controls and previously-infected MBZ-treated rats. Messenger RNA levels for neuropeptide Y were higher in the hypothalamic arcuate nucleus of 8-day infected rats than in recovering MBZ-treated animals. Inoculation of rats with heat-killed N. brasiliensis larvae failed to induce anorexia and did not alter the severity of biphasic anorexia on subsequent injection of viable larvae. The first anorexic episode is therefore dependent upon viable migrating larvae. The second phase of anorexia clearly requires the continuing presence of the parasite beyond the lung phase. Viable migrating larvae are also required to confer 'resistance' to reinfection.

Animals↗
PubMed1999

Toxoplasma gondii infection: analysis of serological response by 2-DE immunoblotting.

Toxoplasma gondii is known to cause a variety of diseases ranging from asymptomatic infections to serious conditions in immunocompromised hosts such as AIDS-patients or transplant recipients. In addition they may cause abortion or fetal abnormalities during pregnancy. Despite the clinical importance, diagnosis, treatment and prevention still remain unsatisfactory. Analysis of the parasitic cell determinants, recognized by specific humoral and cellular immune responses, may have important implications for diagnosis, therapy and vaccination strategies. Two-dimensional electrophoresis (2-DE) was used to resolve and compare protein patterns from Toxoplasma gondii strains RH and BK (mouse virulent strains). Comparison of silver-stained gels showed that 35.2% to 60.3% of the spots had the same position. In a second series of experiments, the reactivity of the spots with human sera was tested. Proteins were transferred to PVDF membranes and were detected with sera from different patient groups. Depending upon the immunoglobulin class (IgG, IgM, IgA or IgE) different epitope patterns were observed. Some of the spots seemed to be recognized in different stages of infection. Sera of two patients with similar serology and comparable stage of infection were compared in order to demonstrate an individual immune response.

Acute Disease↗
PubMed1998

A novel protein complex promoting formation of functional alpha- and gamma-tubulin.

We describe the identification of GIM1/YKE2, GIM2/PAC10, GIM3, GIM4 and GIM5 in a screen for mutants that are synthetically lethal with tub4-1, encoding a mutated yeast gamma-tubulin. The cytoplasmic Gim proteins encoded by these GIM genes are present in common complexes as judged by co-immunoprecipitation and gel filtration experiments. The disruption of any of these genes results in similar phenotypes: the gim null mutants are synthetically lethal with tub4-1 and super-sensitive towards the microtubule-depolymerizing drug benomyl. All except Deltagim4 are cold-sensitive and their microtubules disassemble at 14 degrees C. The Gim proteins have one function related to alpha-tubulin and another to Tub4p, supported by the finding that the benomyl super-sensitivity is caused by a reduced level of alpha-tubulin while the synthetic lethality with tub4-1 is not. In addition, GIM1/YKE2 genetically interacts with two distinct classes of genes, one of which is involved in tubulin folding and the other in microtubule nucleation. We show that the Gim proteins are important for Tub4p function and bind to overproduced Tub4p. The mammalian homologues of GIM1/YKE2 and GIM2/PAC10 rescue the synthetically lethal phenotype with tub4-1 as well as the cold-sensitivity and benomyl super-sensitivity of the yeast deletion mutants. We suggest that the Gim proteins form a protein complex that promotes formation of functional alpha- and gamma-tubulin.

Actins↗
PubMed1997

The spindle pole body component Spc97p interacts with the gamma-tubulin of Saccharomyces cerevisiae and functions in microtubule organization and spindle pole body duplication.

Previously, we have shown that the gamma-tubulin Tub4p and the spindle pole body component Spc98p are involved in microtubule organization by the yeast microtubule organizing centre, the spindle pole body (SPB). In this paper we report the identification of SPC97 encoding an essential SPB component that is in association with the SPB substructures that organize the cytoplasmic and nuclear microtubules. Evidence is provided for a physical and functional interaction between Tub4p, Spc98p and Spc97p: first, temperature-sensitive spc97(ts) mutants are suppressed by high gene dosage of SPC98 or TUB4. Second, Spc97p interacts with Spc98p and Tub4p in the two-hybrid system. Finally, immunoprecipitation and fractionation studies revealed complexes containing Tub4p, Spc98p and Spc97p. Further support for a direct interaction of Tub4p, Spc98p and Spc97p comes from the toxicity of strong SPC97 overexpression which is suppressed by co-overexpression of TUB4 or SPC98. Analysis of temperature-sensitive spc97(ts) alleles revealed multiple spindle defects. While spc97-14 cells are either impaired in SPB separation or mitotic spindle formation, spc97-20 cells show an additional defect in SPB duplication. We discuss a model in which the Tub4p-Spc98p-Spc97p complex is part of the microtubule attachment site at the SPB.

Cloning, Molecular↗
PubMed1996

The spindle pole body component Spc98p interacts with the gamma-tubulin-like Tub4p of Saccharomyces cerevisiae at the sites of microtubule attachment.

Tub4p is a novel tubulin found in Saccharomyces cerevisiae. It most resembles gamma-tubulin and, like it, is localized to the yeast microtubule organizing centre, the spindle pole body (SPB). In this paper we report the identification of SPC98 as a dosage-dependent suppressor of the conditional lethal tub4-1 allele. SPC98 encodes an SPB component of 98 kDa which is identical to the previously described 90 kDa SPB protein. Strong overexpression of SPC98 is toxic, causing cells to arrest with a large bud, defective microtubule structures, undivided nucleus and replicated DNA. The toxicity of SPC98 overexpression was relieved by co-overexpression of TUB4. Further evidence for an interaction between Tub4p and Spc98p came from the synthetic toxicity of tub4-1 and spc98-1 alleles, the dosage-dependent suppression of spc98-4 by TUB4, the binding of Tub4p to Spc98p in the two-hybrid system and the co-immunoprecipitation of Tub4p and Spc98p. In addition, Spc98-1p is defective in its interaction with Tub4p in the two-hybrid system. We suggest a model in which Tub4p and Spc98p form a complex involved in microtubule organization by the SPB.

Amino Acid Sequence↗
PubMed1996

gamma-Tubulin-like Tub4p of Saccharomyces cerevisiae is associated with the spindle pole body substructures that organize microtubules and is required for mitotic spindle formation.

Tub4p is a novel tubulin in Saccharomyces cerevisiae that most closely resembles gamma-tubulin. We report in this manuscript that the essential Tub4p is associated with the inner and outer plaques of the yeast microtubule organizing center, the spindle pole body (SPB). These SPB substructures are involved in the attachment of the nuclear and cytoplasmic microtubules, respectively (Byers, B., and L. Goetsch. 1975. J. Bacteriol. 124:511-523). Study of a temperature sensitive tub4-1 allele revealed that TUB4 has essential functions in microtubule organization. Remarkably, SPB duplication and separation are not impaired in tub4-1 cells incubated at the nonpermissive temperature. However, SPBs from such cells contain less or misdirected nuclear microtubules. Further analysis revealed that tub4-1 cells are able to assemble a short bipolar spindle, suggesting that the defect in microtubule organization occurs after spindle formation. A role of Tub4p in microtubule organization is further suggested by an increase in chromosome loss in tub4-1 cells. In addition, cell cycle arrest and survival of tub4-1 cells is dependent on the mitotic checkpoint control gene BUB2 (Hoyt, M.A., L. Totis, B.T. Roberts. 1991. Cell. 66:507-517), one of the cell's monitors of spindle integrity.

Amino Acid Sequence↗
PubMed1996

Serine protease EpiP from Staphylococcus epidermidis catalyzes the processing of the epidermin precursor peptide.

The function of serine protease EpiP in epidermin biosynthesis was investigated. Epidermin is synthesized as a 52-amino-acid precursor peptide, EpiA, which is posttranslationally modified and processed to the mature 22-amino-acid peptide antibiotic. epiP was expressed in Staphylococcus carnosus with xylose-regulated expression vector pCX15. The cleavage of the unmodified EpiA precursor peptide to leader peptide and proepidermin by EpiP-containing culture filtrates of S. carnosus (pCX15epiP) was followed by reversed-phase chromatography and subsequent electrospray mass spectrometry.

Amino Acid Sequence↗
PubMed1993

A counterselectable pACYC184-based lacZ alpha-complementing plasmid vector with novel multiple cloning sites; construction of chromosomal deletions in Klebsiella pneumoniae.

We have constructed a series of small, chloramphenicol-resistance-encoding, lacZ alpha-complementing vectors with novel multiple cloning sites, based on the pACYC184 replicon. The sacB gene of Bacillus subtilis, which is lethal to Gram- organisms in the presence of sucrose, was cloned into one of these, giving the counterselectable vector pSG335. This was used to substitute a streptomycin-resistance-encoding cassette for the ntrBC genes in the Klebsiella pneumoniae chromosome.

Base Sequence↗
PubMed1990

[The reduction of radiation burden in mammography using film-screen combination systems].

The comparison of mammographic image recording systems TF-13-nonscreen film and ORTHO-MA with MIN-R screens leads to the necessary conclusion, that mammography should be carried out only with screen film combinations and an anti-scatter grid. This means improved contrast and a reduction of radiation dose to 1/3 of the dose of TF 13. Since in the GDR the film XR 10 still is used as mammographic film the fourfold of the internationally possible dose is required. The urgent change of the situation can only be achieved with respective imports.

Adult↗
PubMed1987

[Current therapy of chronic arterial occlusive diseases of the lower extremities].

Angiologists, vascular surgeons, and angiographers inform about the actual state of the therapy of the arterial occlusive diseases of the legs. The degree I of therapy comprises the conservative treatment for the improvement of the macrocirculation and the normalisation of the disturbed microcirculation, taking into particular consideration the therapy with antiviscositant drugs. The main chapter ends with the possibilities of the influence on the arteriosclerotic vascular processes as well as with the necessary rehabilitative measures. In the paragraph about the degree II of therapy the indications, contraindications, methods and results of the isolated and combined percutaneous transluminal angioplasty, the systemic and local fibrinolysis as well as the reconstructive vascular operations are represented.

Arterial Occlusive Diseases↗
PubMed1987

[Radiation dosage of the lens and gonads in selected CT studies].

The article is a compilation of data on the radiation exposure during the most important CT examinations. The influencing parameters are assessed and their effects are discussed. Conclusions are drawn to modify the practical approach. These results are compared with those reported in international literature.

Brain↗
PubMed1986

[Aggressive fibromatoses. Treatment concept and results with special reference to ultrasound diagnosis].

Therapeutic tactics and control regime for aggressive fibromatosis are described in this paper, with reference being made to the authors' own patients. Locally delimited, wide excision without supporting radiotherapy is recommended also for recurrent cases. Anti-oestrogenic treatment has now been adopted to cope with locally delimited inoperability. The polytopic, usually congenital form of aggressive fibromatosis must be interpreted as a particularly unfavourable course with potential malignancy. Sonography so far has proved to be a suitable approach to pre-operative and postoperative screening.

Adult↗