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S Greiner

Publications and source records attributed to S Greiner.

18 recordsLinked to original sources
PubMed2007

The effect of zoledronic acid incorporated in a poly(D,L-lactide) implant coating on osteoblasts in vitro.

Bisphosphonates such as zoledronic acid (ZOL) are used in diseases associated with osteoclast-mediated bone loss. However, their antiresorptive activity is partly due to their effect on osteoblasts. Local application might increase the therapeutical fence and their local efficiency and reduce systemic side effects. Aim of the study was to investigate the effect of ZOL on human osteoblasts like cells in vitro with special focus on the synthesis of factors mediating osteoclast differentiation (RANKL, OPG). ZOL was incorporated in an implant coating based on poly(D,L-lactide) (PDLLA) in different concentrations (10-150 microM). Control groups were treated with uncoated implants, PDLLA-coated implants, and ZOL pure substance in corresponding concentrations. After an experimental period of 144 h, primary human osteoblasts were stained with alamar blue and cell viability was measured. Procollagen I synthesis, osteoprotegerin (OPG) secretion, and soluble receptor activator of nuclear factor-kappaB ligand (sRANKL) were analyzed. Results showed that cell viability was not affected when treated with doses equivalent up to 100 microM ZOL-coated implants (ZOL-CI). Procollagen I synthesis was highest when treated with 50 microM ZOL-CI. OPG increased significantly in the 10 microM ZOL-CI group, whereas sRANKL decreased significantly with different concentrations of ZOL-CI. Higher concentrations or exposure to the pure substance showed a decrease in cell viability, collagen I, OPG, and sRANKL synthesis. In conclusion, exposure to specific concentrations of ZOL-CI showed a beneficial effect on osteoblast differentiation and protein synthesis without influencing their proliferation. Changes in sRANKL and OPG production may contribute to the inhibition of osteoclastic bone resorption. This local antiresorptive effect might be clinically useful in osseous implant integration and fracture healing.

Antigens, Differentiation↗
PubMed2006

The highly attenuated vaccinia virus strain modified virus Ankara induces apoptosis in melanoma cells and allows bystander dendritic cells to generate a potent anti-tumoral immunity.

Vaccinia virus (VV) has been tested as oncolytic virus against malignant melanoma in clinical trials for more than 40 years. Until now, mainly strains comparable to viral strains used for smallpox vaccination have been probed for anti-tumoral therapy. We have shown recently that the wild-type strain Western Reserve (WR) can interfere with crucial functions of monocyte-derived dendritic cells (DCs). Our aim was to examine whether viral immune evasion mechanisms might be responsible for the ineffectiveness of WR-based vaccination strategies and whether the highly attenuated strain modified virus Ankara (MVA) differs from WR with respect to its possible immunostimulatory capacity after intratumoral injection. Using in vitro experiments, we compared the effect of both strains on melanoma cells and on local bystander DCs. We found that both VV-strains infected melanoma cells efficiently and caused disintegration of the actin cytoskeleton, as shown by fluorescence microscopy. In addition, both VV-strains caused apoptotic cell death in melanoma cells after infection. In contrast to MVA, WR underwent a complete viral replication cycle in melanoma cells. Bystander DCs were consecutively infected by newly generated WR virions and lost their capacity to induce allogeneic T cell proliferation. DCs in contact with MVA-infected melanoma cells retained their capacity to induce T cell proliferation. Immature DCs were capable of phagocytosing MVA-infected melanoma cells. Priming of autologous CD8(+) T cells by DCs that had phagocytosed MVA-infected, MelanA positive melanoma cells resulted in the induction of T cell clones specifically reactive against the model antigen MelanA as shown by enzyme-linked immunospot (ELISPOT) analysis. We conclude that the clinical trials with oncolytic wild-type VV failed probably because of suppression of bystander DCs and consecutive suppression of T cell-mediated anti-melanoma immunity. The attenuated VV-strain MVA facilitates the generation of tumour associated antigen (TAA)-specific T cell response as it is oncolytic for melanoma cells, but non-toxic for DC, and should be a promising candidate for intralesional metastatic melanoma therapy.

Actins↗
PubMed2002

[Patient evaluation of postoperative recovery. An evaluation of the QoR scores in 577 patients].

BACKGROUND: In 1999 Myles and co-workers presented their quality of recovery score (QoR score) as a tool to evaluate postoperative recovery and to measure patient satisfaction. It was developed according to predefined psychological standards and its reliability and validity had been proven in large clinical trials. The aim of this study was to evaluate a German version of the QoR in a heterogeneous group of surgical patients. METHODS: A total of 577 unselected patients completed a modified questionnaire. The response rate and time spent on completing the test were recorded. A stepwise multivariate regression analysis identified factors with significant impact on the QoR score. Other analyses were performed descriptively. RESULTS: Of the patients 83% completed the questionnaire in a median time of 9 h after surgery without assistance. For 75% of these it took 2 min or less. The median QoR score was 15 (10(th)/90(th) percentile: 11/18). Cronbach's p (=0.63) and mean corrected item correlation (=0.32) were used as measures of internal reliability. Factors with impact on the QoR score were: period of time after surgery when performing the test, severity of surgery, sex, general vs local anaesthesia, duration of anaesthesia, and age. CONCLUSIONS: The German translation of the QoR score is easily applicable to a heterogeneous surgical population and thus can be used as a valuable measure of quality of anaesthesia care and patient satisfaction.

Adult↗
PubMed2001

In wounded sugar beet (Beta vulgaris L.) tap-root, hexose accumulation correlates with the induction of a vacuolar invertase isoform.

Wounding of sugar beet tap-root causes an induction of invertase activity, which contributes to post-harvest sucrose losses. In this first comprehensive monitoring of wound-induced invertase mRNAs, proteins, enzyme activities, and tissue hexose concentrations, the VI isoform responsible for wound-induced hexose accumulation in mature tap-root could be identified.

Adaptation, Physiological↗
PubMed2000

Regulation of ferritin-mediated cytoplasmic iron storage by the ferric uptake regulator homolog (Fur) of Helicobacter pylori.

Homologs of the ferric uptake regulator Fur and the iron storage protein ferritin play a central role in maintaining iron homeostasis in bacteria. The gastric pathogen Helicobacter pylori contains an iron-induced prokaryotic ferritin (Pfr) which has been shown to be involved in protection against metal toxicity and a Fur homolog which has not been functionally characterized in H. pylori. Analysis of an isogenic fur-negative mutant revealed that H. pylori Fur is required for metal-dependent regulation of ferritin. Iron starvation, as well as medium supplementation with nickel, zinc, copper, and manganese at nontoxic concentrations, repressed synthesis of ferritin in the wild-type strain but not in the H. pylori fur mutant. Fur-mediated regulation of ferritin synthesis occurs at the mRNA level. With respect to the regulation of ferritin expression, Fur behaves like a global metal-dependent repressor which is activated under iron-restricted conditions but also responds to different metals. Downregulation of ferritin expression by Fur might secure the availability of free iron in the cytoplasm, especially if iron is scarce or titrated out by other metals.

Bacterial Proteins↗
PubMed1999

Biochemical and immunologic comparison of virus-like particles for a rotavirus subunit vaccine.

A parenterally administered rotavirus vaccine composed of virus-like particles (VLPs) is being evaluated for human use. VLPs composed of bovine VP6 and simian VP7 (SA11, G3) proteins (6/7-VLPs) or of bovine VP2, bovine VP6, and simian VP7 (SA11, G3) proteins (2/6/7-VLPs) were synthesized and purified from Sf9 insect cells co-infected with recombinant baculoviruses. 6/7- and 2/6/7-VLP administered parenterally (i.m.) in mice had comparable immunogenicity, but the 2/6/7-VLPs were more homogeneous and stable. The inclusion of the VP2 capsid contributed to particle formation and stability. The adjuvant QS-21 significantly enhanced the immunogenicity of 2/6/7-VLPs over A10H or saline alone. Equivalent serum neutralizing antibody responses were induced over the range of 1-15 microg/dose of 2/6/7-VLPs administered with the range of 5-20 microg/dose of QS-21. The immunogenicity of 2/6/7-VLPs and inactivated SA11 virus were comparable. 2/6/7-VLPs are a promising candidate for a parenterally delivered rotavirus subunit vaccine.

Adjuvants, Immunologic↗
PubMed1999

Radiochemotherapy with paclitaxel: synchronization effects and the role of p53.

PURPOSE: We have studied the interaction of paclitaxel (Taxol) and radiation in V79 cells and human lymphoblasts with special emphasis on cell cycle effects and the role of p53. MATERIAL AND METHODS: V79 cells in log- and plateau-phase and human lymphoblasts (p53wt TK6 and p53mut WTK1) were used. Paclitaxel was given for 2 hours. Survival was determined using clonogenic assays. Cell cycle analysis was done using DNA flow cytometry. RESULTS: In V79 cells there was a dose dependent delay of colony formation after paclitaxel. The LD50 was about 0.4 microM with a 2-hour exposure. In exponentially growing cells, there was an accumulation of 40% of cells in G2/M 6 hours after paclitaxel. The dose modification factor was about 3.9 when radiation was given 6 hours after 0.3 microM paclitaxel for 2 hours. Synchronization experiments using serum starvation and induction showed that synchronization was not sufficient to induce a comparable dose modification factor. Human lymphoblasts with mutated p53 (WTK1, LD50 = 75 microM) were more resistant to paclitaxel than wild type p53 cells (TK6, LD50 = 25 microM). CONCLUSION: The radiosensitization induced by paclitaxel was critically dependent on the timing of irradiation and chemotherapy, although synchronization alone was not sufficient to explain the dose modification. Lymphoblasts with mutated p53 were less sensitive than wild type p53 cells.

Cell Cycle↗
PubMed1999

The ferric uptake regulator (Fur) homologue of Helicobacter pylori: functional analysis of the coding gene and controlled production of the recombinant protein in Escherichia coli.

A homologue of the ferric uptake regulator protein Fur has recently been identified within the Helicobacter pylori genome. The promoterless gene on a plasmid did partially complement a fur-negative mutant of Escherichia coli, and was strongly positive in the Fur titration assay (FURTA). The genetic and functional characterization of the complete fur homologue performed in this study revealed that the gene is conserved among H. pylori strains ( > 95% identity), and does not carry nucleotide transitions in iron-resistant mutants of H. pylori. The fur homologue on a plasmid mediated full iron-dependent ferric uptake regulator activity in the fur-deficient mutant strains H1681 and H1780 of E. coli. Immunoblot analysis revealed that Fur from H. pylori cross-reacts with antibodies raised against Fur from E. coli. The fact that inactivation of the fur gene abolished the FURTA-positive phenotype in the E. coli indicator strain H1717, indicated that this phenotype is rather caused by the encoded protein than by real Fur titration. Subcloning of the fur gene into an expression vector allowed controlled production in E. coli, and purification of a recombinant version of the H. pylori Fur protein. In summary, the results confirm the function of the H. pylori Fur homologue as iron-dependent transcriptional repressor by its ability to interact with the Fur-regulated promoters of the genes fiu and fhuF in E. coli.

Amino Acid Sequence↗
PubMed1999

Ectopic expression of a tobacco invertase inhibitor homolog prevents cold-induced sweetening of potato tubers.

We have transformed potato with Nt-inhh cDNA, encoding a putative vacuolar homolog of a tobacco cell wall invertase inhibitor, under the control of the CaMV 35S promoter. In transgenic tubers, cold-induced hexose accumulation was reduced by up to 75%, without any effect on potato tuber yield. Processing quality of tubers was greatly improved without changing starch quantity or quality, an important prerequisite for the biotechnological use of Nt-inhh for potato transformation.

Amino Acid Sequence↗
PubMed1998

Cloning of a tobacco apoplasmic invertase inhibitor. Proof of function of the recombinant protein and expression analysis during plant development.

Higher plants express several isoforms of vacuolar and cell wall invertases (CWI), some of which are inactivated by inhibitory proteins at certain stages of plant development. We have purified an apoplasmic inhibitor (INH) of tobacco (Nicotiana tabacum) CWI to homogeneity. Based on sequences from tryptic fragments, we have isolated a full-length INH-encoding cDNA clone (Nt-inh1) via a reverse transcriptase-polymerase chain reaction. Southern-blot analysis revealed that INH is encoded by a single- or low-copy gene. Comparison with expressed sequence tag clones from Arabidopsis thaliana and Citrus unshiu indicated the presence of Nt-inh1-related proteins in other plants. The recombinant Nt-inh1-encoded protein inhibits CWI from tobacco and Chenopodium rubrum suspension-cultured cells and vacuolar invertase from tomato (Lycopersicon esculentum) fruit, whereas yeast invertase is not affected. However, only in the homologous system is the inhibition modulated by the concentration of Suc as previously shown for INH isolated from tobacco cells. Highly specific binding of INH to CWI could be shown by affinity chromatography of a total cell wall protein fraction on immobilized recombinant Nt-inh1 protein. RNA-blot analysis of relative transcript ratios for Nt-inh1 and CWI in different parts of adult tobacco plants revealed that the expression of both proteins is not always coordinate.

Amino Acid Sequence↗
PubMed1997

In seedlings of the heavy metal accumulator Brassica juncea Cu2+ differentially affects transcript amounts for gamma-glutamylcysteine synthetase (gamma-ECS) and metallothionein (MT2).

Glutathione (GSH) is the precursor of the phytochelatins (PC), which in plants and fungi are involved in heavy metal sequestration. The regulatory enzyme gamma-glutamylcysteine synthetase (gamma-ECS) catalyzes the first step in GSH biosynthesis. For the heavy metal accumulator Brassica juncea L. a partial gamma-ECS cDNA was cloned by RT-PCR. Treatment of suspension-cultured dark grown seedlings with micromolar concentrations of CuSO4 resulted in a strong increase of gamma-ECS mRNA in roots and shoots, concomitant with an increase of GSH and phytochelatins. A significant up-regulation of gamma-ECS mRNA was observed at 25 microM CuSO4 (shoot growth: -11%), whereas maximum up-regulation was obtained at 100 microM CuSO4 (shoot growth: -60%). Unexpectedly, metallothionein 2 (MT2) mRNA was decreased in response to the CuSO4 treatments. CdSO4 at a concentration of 50 microM caused a 72% reduction in shoot growth without affecting the amounts of gamma-ECS- and MT2 mRNAs. ZnSO4 at a concentration of 500 microM did not reduce growth but induced transient increases of gamma-ECS- and MT2 mRNAs. The implications of the results with respect to differential regulation of gamma-ECS and MT2 during heavy metal exposure are discussed.

Arabidopsis↗
PubMed1996

Sucrose protects cell wall invertase but not vacuolar invertase against proteinaceous inhibitors.

Vacuolar (VI) and cell wall invertases (CWI) of higher plants can be inactivated in vitro and, possibly, in vivo by proteinaceous inhibitors. The respective mechanisms have not yet been compared. Therefore, partially purified CWI from transformed tobacco cells and VI from tomato fruit were preincubated with invertase-inhibitor fractions isolated from the same tissues. Both inhibitors were able to inhibit both invertases. However, VI was fully inhibited within less than 1 min by both inhibitors, whereas inactivation of CWI was much slower. Furthermore, CWI, but not VI, was strongly protected against inhibition by sucrose. A polyclonal antiserum directed against the tobacco inhibitor (I(NT)) cross-reacted with a 19 kDa polypeptide in the partially purified tomato inhibitor (I(LE)) fraction. The results indicate that I(NT) and I(LE)have similar structural properties, whereas the mechanism of inactivation is clearly different for CWI and VI.

Agrobacterium tumefaciens↗
PubMed1996

Virus-like particles as a rotavirus subunit vaccine.

Rotavirus subunit vaccines are being evaluated for use in humans. The virus-like particles (VLPs) for these vaccines are produced in insect cells coinfected with combinations of baculovirus recombinants expressing bovine RIF VP2 and simian SA11, VP4, VP6, or VP7 rotavirus proteins. VLPs were administered parenterally to mice and rabbits, and the immunogenicity and protective efficacy of the vaccines were evaluated. Rabbits vaccinated with VP2/4/6/7 or VP2/6/7 VLP combinations developed high levels of rotavirus-specific serum antibody and fecal IgG but not fecal IgA. The induction of fecal IgG was associated with total or partial protection from oral challenge with ALA rotavirus. Heterotypic serum and fecal neutralizing antibody was induced in mice vaccinated parenterally with G1 VP2/6/7 or VP2/4/6n VLPs. VLPs were highly immunogenic when administered in QS21 adjuvant, inducing serum neutralizing antibody titers comparable to those induced by SA11 virus. VLPs are effective immunogens when administered parenterally and may be an effective subunit vaccine.

Animals↗
PubMed1996

[The oldest German textbook on internal medicine of horses, edited at the Kayserlich-Köngliche Pferd-Cur und Operations Schul in Vienna in 1770].

The manuscript has the title: "Erkandtnus deren innerlichen Krankheiten des Pferds überhaupt". Through two take downs of the lectures of Ludwig Scotti, the founder of the first school for veterinarians in the German speaking part of Europe and its first teacher, the manuscript is identified as another take down. The first part of the manuscript, which is about internal medicine, in large passages is a literally translation of Lafosse's "Guide de Maréchal". In most passages the second part, which is about pharmacology, is a copy of the German translation of Claude Bourgelat's "Matière médicale" published in 1766. Nevertheless Scotti brings in his own experiences by inserting in or rewriting of some chapters or by adding other theories, likewise his prescriptions cannot be found in Bourgelat's book. The manuscript is an example for the highest level in veterinary science in the second half of the 18th century. This is emphasized through the comparison with contemporary literature in German language, for example the books of von Sind and Deigendesch.

Animals↗
PubMed1993

CA 494--a new tumor marker for the diagnosis of pancreatic cancer.

In 59 patients with ductal pancreatic cancer the monoclonal antibody (MAb) BW 494, which detects the CA 494 glycoprotein antigen, was analyzed in comparison with the reference tumor markers CA 19-9 and CEA. Eighty-one patients with non-pancreatic malignancies of the gastrointestinal (GI) tract, 95 with chronic pancreatitis, 124 with benign non-pancreatic GI diseases, 30 with diabetes mellitus (type I or type II) and 114 healthy blood donors served as controls. The sensitivity of pancreatic cancer was 90%, 44% and 90% for CA 19-9, CEA and CA 494, respectively. In chronic pancreatitis, as the most important control population for pancreatic cancer, the specificity was 85%, 72% and 94% for CA 19-9, CEA and CA 494, respectively.

Adolescent↗
PubMedDate not supplied

Comparison between human sperm preservation medium and TEST-yolk buffer on protecting chromatin and morphology integrity of human spermatozoa in fertile and subfertile men after freeze-thawing procedure.

The aim of this study was to identify the detrimental effect of the freeze-thaw process on chromatin integrity and morphology of human spermatozoa, and to determine whether human sperm preservation medium (HSPM) or TEST-yolk buffer (TYB) offers a better protection to spermatozoa from cryodamage after the freeze-thaw procedure. Thirty-five semen samples obtained from couples childless because of male factor infertility (subfertile men, group 1) and 25 semen samples from healthy, normal volunteers of proven fertility (group 2) were included in the study. Each semen sample was divided into 2 parts, the first part was mixed with HSPM and the other with TYB (1:1), and frozen with a controlled slow-stage freezer, before plunging into liquid nitrogen. Twelve smears from each semen sample were made before (n = 4) and after (n = 8) the freeze-thaw process. Chromatin structure was evaluated after staining using the acridine orange (AO) test, whereas morphology was analyzed according to strict criteria. The mean percentage of spermatozoa that exhibited normal morphology and intact chromatin structure was decreased after freeze-thaw in all samples treated with HSPM or TYB in comparison with the value observed in the native semen samples of both groups. However, TYB preserved chromatin and morphology significantly better than HSPM did (9.3% +/- 5.6% and 88.7% +/- 11.2% vs. 7.8% +/- 4.2% and 85.5% +/- 12.5%, respectively). Therefore, TYB could be recommended as a first choice cryoprotectant for semen preservation in order to avoid extra chromatin structure damage and morphology alterations of spermatozoa not only for patients pursuing assisted reproduction, but also for donor samples.

Cell Survival↗