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Biomedical subjects

C Hiller

Publications and source records attributed to C Hiller.

At least 19 recordsLinked to original sources
PubMed2000

Herpesvirus saimiri pathogenicity enhanced by thymidine kinase of herpes simplex virus.

Herpesvirus saimiri can be used as an efficient gene expression vector for human T lymphocytes and thus may allow applications in experimental leukemia therapy. We constructed recombinant viruses for the functional expression of the thymidine kinase (TK) of herpes simplex virus type 1 (HSV) as a suicide gene. These viruses reliably allowed the targeted elimination of transduced nonpermissive human T cells in vitro after the administration of ganciclovir. To test the reliability of this function under the most stringent permissive conditions, in this study we analyzed the influence of the prodrugs ganciclovir and acyclovir in common marmosets on the acute leukemogenesis induced by either wild-type herpesvirus saimiri C488 or by a recombinant derivative expressing TK of HSV. Antiviral drug treatment did not influence the rapid development of acute disease. In contrast, the presence of the HSV tk gene resulted in a faster disease progression. In addition, HSV TK-expressing viruses showed faster replication than wild-type virus in culture at low serum concentrations. Thus, HSV TK accelerates the replication of herpesvirus saimiri and enhances its pathogenicity. This should be generally considered when HSV TK is applied as a transgene in replication-competent DNA virus vectors for gene therapy.

Acyclovir↗
PubMed2000

Functional long-term thymidine kinase suicide gene expression in human T cells using a herpesvirus saimiri vector.

Herpesvirus saimiri transforms human T lymphocytes to stable growth and persists episomally without genomic integration and without virus production. The transformed T cells retain essential features of their parental cells including the MHC-restricted antigen specificity which may be useful for applications in adoptive immunotherapy. In order to improve the biological safety of such vectors, the prodrug activating gene thymidine kinase of herpes simplex virus was inserted into the genome of herpesvirus saimiri by homologous recombination. After infection with wild-type or cloned recombinant viruses, T cells from tamarin monkeys and from humans were transformed to stable growth. Thymidine kinase-expressing transformed T cells were efficiently eliminated in the presence of low concentrations of ganciclovir. This elimination mechanism remained fully functional over an observation period of 12 months. The potentially immunogenic neomycin resistance gene expression cassette was deleted from the genome of established mutant viruses by using the prokaryotic Cre/LoxP recombination system. At any time during the course of a therapeutic application, thymidine kinase-expressing transformed human T cells might be eliminated after administration of ganciclovir. In principle, this function could be useful for the T cell-dependent immunotherapy of resistant blood cancer while avoiding the risk of uncontrolled graft-versus-host disease.

Acyclovir↗
PubMed1998

RigFit: a new approach to superimposing ligand molecules.

If structural knowledge of a receptor under consideration is lacking, drug design approaches focus on similarity or dissimilarity analysis of putative ligands. In this context the mutual ligand superposition is of utmost importance. Methods that are rapid enough to facilitate interactive usage, that allow to process sets of conformers and that enable database screening are of special interest here. The ability to superpose molecular fragments instead of entire molecules has proven to be helpful too. The RIGFIT approach meets these requirements and has several additional advantages. In three distinct test applications, we evaluated how closely we can approximate the observed relative orientation for a set of known crystal structures, we employed RIGFIT as a fragment placement procedure, and we performed a fragment-based database screening. The run time of RIGFIT can be traded off against its accuracy. To be competitive in accuracy with another state-of-the-art alignment tool, with which we compare our method explicitly, computing times of about 6 s per superposition on a common day workstation are required. If longer run times can be afforded the accuracy increases significantly. RIGFIT is part of the flexible superposition software FLEXS which can be accessed on the WWW [http:/(/)cartan.gmd.de/FlexS].

Algorithms↗
PubMed1998

T-cell lymphoma caused by herpesvirus saimiri C488 independently of ie14/vsag, a viral gene with superantigen homology.

The immediate-early gene ie14/vsag of herpesvirus saimiri has homology with murine superantigens. We compared the pathogenesis of infection with either ie14/vsag deletion mutants or wild-type virus C488 in cottontop tamarin monkeys (Saguinus oedipus). Two weeks after infection, all animals developed acute T-cell lymphomas independently of the presence of the viral ie14/vsag gene.

Animals↗
PubMed1998

The interleukin-17 gene of herpesvirus saimiri.

In comparison to wild-type herpesvirus saimiri, viral interleukin-17 gene knockout mutants have unaltered behavior regarding viral replication, T-cell transformation in vitro, and pathogenicity in cottontop tamarins. Thus, this gene is not required for T-cell lymphoma induction but may contribute to apathogenic viral persistence in the natural host, the squirrel monkey.

Animals↗
PubMed1997

Determination of albuterol in plasma after aerosol inhalation by gas chromatography-mass spectrometry with selected-ion monitoring.

Albuterol is a beta2-adrenergic agonist commonly used as a bronchodilator for the treatment of patients with asthma. We have developed an assay to determine plasma levels as low as 50 pg/ml of albuterol by gas chromatography-mass spectrometry (GC-MS). This assay utilizes isotopically labeled albuterol ([13C]albuterol) as an internal standard. In this assay albuterol and the internal standard are recovered from 1 ml of plasma using solid-phase extraction. The samples are then derivatized to trimethylsilyl ethers using N,O-bis(trimethylsilyl)trifluoro-acetamide with 1% trimethylchlorosilane. The samples are then analyzed by GC-MS with selected-ion monitoring (SIM) for the ions m/z 369.15 and 370.15. The method has been validated for a concentration range of 50-10000 pg/ml in plasma.

Administration, Inhalation↗
PubMed1997

The superantigen-homologous viral immediate-early gene ie14/vsag in herpesvirus saimiri-transformed human T cells.

Herpesvirus saimiri C488 transforms human T lymphocytes to stable growth in culture. The growth-transformed human T cells harbor the viral genome in a nonintegrated episomal form without production of virus particles. In these cells, virus gene expression was previously found to be confined to the transforming genes stpC and tip. In order to analyze virus gene expression in more detail, we applied a subtractive hybridization technique and compared stimulated virus-transformed cells with uninfected parental T cells of the same donor. A number of known T-cell activation genes were isolated. Viral stpC/tip cDNAs were enriched after subtraction. In addition, the viral immediate-early, superantigen-homologous gene ie14/vsag was represented by numerous cDNA clones that comprised the entire spliced transcript. Whereas a weak basal expression of ie14/vsag was detected by reverse transcription-PCR only, the phorbol ester-induced transcripts were readily shown by Northern blotting. ie14/vsag, which before had been classified as a major immediate-early gene of herpesvirus saimiri, is localized within a highly conserved region with extensive homologies to the cellular genome. Mutant viruses without the ie14/vsag gene are replication competent and fully capable of transforming human and marmoset T cells. Since ie14/vsag is transiently expressed after stimulation, it may increase T-cell proliferation in an activation-dependent and superantigen-like but apparently Vbeta-independent way.

Animals↗
PubMed1990

[Simplified storage procedure of cryopreserved human parathyroid tissue].

Parathyroid tissue that is stored for replantation purposes is usually kept in a special tank containing fluid nitrogen at -196 degrees C. Our studies demonstrate that storage is also possible in a deep-freezer at -70 degrees C without any loss of quality. Most hospitals own such freezers for storing bone marrow cells at the same temperature. Parathyroid tissue of 11 patients who were operated on because of primary hyperparathyroidism was stored in this way. After six months the tissue showed 75.7% morphologically intact cells. The control group's tissue was stored in liquid nitrogen according to the common method; after the same period of time it showed 76% histologically normal cells.

Adenoma↗
PubMed1989

Nucleotide sequence of a cDNA coding for the NADPH-protochlorophyllide oxidoreductase (PCR) of barley (Hordeum vulgare L.) and its expression in Escherichia coli.

The primary structure of the NADPH-protochlorophyllide oxidoreductase of barley has been deduced from the nucleotide sequence of a cloned full-length cDNA. This cDNA hybridizes to a 1.7 kb RNA whose steady-state level in dark-grown seedlings is drastically reduced upon illumination. The predicted amino acid sequence (388 residues in length) includes a transit peptide of 74 amino acids whose end point has been delimited by sequencing the N-terminus of the mature protein. Expression of the cDNA in Escherichia coli leads to the synthesis of an enzymatically active precursor of the NADPH-protochlorophyllide oxidoreductase. Activity of this protein in bacterial lysates is completely dependent on the presence of NADPH and protochlorophyllide and requires light.

Amino Acid Sequence↗
PubMed1988

Leaf-specific thionins of barley-a novel class of cell wall proteins toxic to plant-pathogenic fungi and possibly involved in the defence mechanism of plants.

A novel class of highly abundant polypeptides with antifungal activity has been detected in cell walls of barley leaves. Similar polypeptides known as thionins occur not only in monocotyledonous but also in various dictoyledonous plants. The leaf-specific thionins of barley are encoded by a complex multigene family, which consists of at least 50-100 members per haploid genome. All of these genes are confined to chromosome 6. The toxicity of these thionins for plant pathogenic fungi and the fact that their synthesis can also be triggered by pathogens strongly suggest that thionins are a naturally occurring, inducible plant protein possibly involved in the mechanism of plant defence against microbial infections.

Journal Article↗
PubMed1984

Characterization of a beta-adrenergic receptor in porcine trachealis muscle.

To establish a model of airway smooth muscle function we studied binding of [3H]dihydroalprenolol [( 3H]DHA), a beta-adrenergic antagonist, to membrane preparations of porcine trachealis muscle and investigated the response of adenylate cyclase to l-isoproterenol in tissue and plasma membranes. [3H]DHA binding was of high affinity (Kd = 1.0 +/- 0.1 nM), was saturable (Bmax = 87.6 +/- 13.2 fmol/mg protein), and was 90% beta 2 and 10% beta 1. Adenylate cyclase activity in the membrane preparation was (in pmol.10 min-1.mg protein-1 +/- SE): basal 420 +/- 74, guanosine 5'-triphosphate (GTP) (10 micron) 600 +/- 45, GTP (10 microM) + l-isoproterenol (100 microM) 660 +/- 63, NaF (10 mM) 1,500 +/- 134, and forskolin (100 microM) 3,000 +/- 410. Guanosine 5'-diphosphate (GDP) and GTP were active cofactors; l-isoproterenol appeared to function as an effector exchanging GTP for GDP on the guanine nucleotide regulatory protein. There was close agreement of the effective dose (ED50) of the l-isoproterenol-induced relaxation (0.95 +/- 0.45 microM) and the inhibitory constant of l-isoproterenol binding (0.39 +/- 0.10 microM). l-Isoproterenol (100 microM) induced a 100% increase in adenosine 3',5'-cyclic monophosphate (cAMP) levels in tissue strips over basal activity. Investigation of the difference in adenylate cyclase activity between tissue and plasma membranes revealed that l-isoproterenol responsive adenylate cyclase was diminished after initial homogenization. Electron microscopy demonstrated disruption of all cells at this early stage of preparation. The decrease in l-isoproterenol responsive adenylate cyclase following cell rupture is different from other tissues and suggests a difference in the actions of beta-agonist in smooth muscle compared with other tissues.

Adenylyl Cyclases↗
PubMed1983

On regional mapping of human chromosome 6. Review and own findings.

In addition to the committee Reports on the Constitution of Chromosome 6 also the mapping contributions from patients with no. 6 imbalances were added to the scheme. Moreover own PGM 3 : GLO : HLA linkage data are given. The controversially discussed gene order of these three loci was analysed from appropriate backcross families. The most likely gene order is HLA-A, C, B : BF (C2, C4) : HLA-D/DR : GLO (all at about 6p 21-p22) : 6 ph (centromer) : PGM3 (6q12): ME 1 (6q12-q15) : SOD 2 (6q21).

Chromosome Mapping↗
PubMed1981

Hereditary ataxia and the sixth chromosome.

Possible linkage of the gene or genes for dominant hereditary ataxia and three genetic markers on the short arm of the sixth chromosome (HLA, properdin factor B [Bf], and glyoxalase I) was investigated in five families. Logarithmic odds (lod scores) were calculated for the linkages and found to be either inconclusive or in favor of nonlinkage. Caution is advised in the summing of lod scores for separate families because of the wide spectrum of clinical and anatomical manifestations of dominant hereditary ataxia. Three families with recessive hereditary ataxia were also studied. Identical haplotypes occurred in affected and unaffected siblings. It did not appear likely that the recessive genes of the parents were transmitted in linkage with the markers on the short arm of the sixth chromosome.

Ataxia↗
PubMed1980

[The battered child (Medical and legal questions for the gynaecologist) (author's transl)].

The syndrome of the battered child is described. The legal problems arising from the conflicts between the two basic rights of medical confidentiality and protection of the child are discussed. The relevant paragraphs of the penal code, the civil code and the West German constitution are discussed. A practical solution for the physician in this conflict situation is information of the finding of a trauma of unknown origin to the child protection agency.

Battered Child Syndrome↗