Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 34
Filter
1.
J Hosp Infect ; 97(3): 234-240, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28797758

ABSTRACT

BACKGROUND: Much of the existing literature on the epidemiology of multidrug-resistant bacterial organisms (MDROs) and infection control measures still concentrates on hospital care settings. AIM: To pilot a cross-sectional survey in long-term care facilities (LTCFs), rehabilitation clinics, and homecare services to assess the prevalence of MDROs, structural data on infection control, and referral links between care settings in the state of Mecklenburg-West Pomerania, Germany, in 2015. METHODS: A voluntary, anonymous, point prevalence survey, using routine microbiological and structural data (MDRO screening strategies) and the compliance of referring facilities with MRDO patient transfer sheets that are mandatory in Germany. Data from 39 facilities including 24 LTCFs, nine rehabilitation clinics, and six homecare services were analysed. FINDINGS: The most reported pathogen was meticillin-resistant Staphylococcus aureus (MRSA) with a prevalence of 2.09% in homecare services, 1.43% in LTCFs, and 0.53% in rehabilitation clinics. Missing information on the MRDO status in the referral documents was a relevant problem in all facility types. CONCLUSION: Our results imply strong epidemiological links between acute care hospitals and non-clinical care settings. This underlines that successful efforts to curb antimicrobial resistance must not be limited to single facilities but include different settings that are linked by referral networks. Compared to surveys in clinical settings that used the same approach, the prevalence of MRSA is comparable to that of hospitals. By contrast, care facilities lack the infection control resources of hospitals.


Subject(s)
Bacterial Infections/epidemiology , Cross Infection/epidemiology , Drug Resistance, Multiple, Bacterial , Health Facilities , Home Care Services , Infection Control/methods , Bacterial Infections/microbiology , Cross Infection/prevention & control , Cross-Sectional Studies , Germany/epidemiology , Humans , Long-Term Care , Prevalence
2.
Am J Infect Control ; 44(6): e91-4, 2016 06 01.
Article in English | MEDLINE | ID: mdl-26897700

ABSTRACT

There were 256 health care workers in 39 facilities who were interviewed about their perceptions of the quality of care of patients with and without multidrug-resistant organisms based on a standardized questionnaire. There are remarkable differences in the responses between facility types (acute care hospitals, long-term care hospitals, rehabilitation hospitals, and home care services). Hygiene management must be specifically tailored to the requirements of each facility.


Subject(s)
Attitude of Health Personnel , Drug Resistance, Multiple, Bacterial , Health Knowledge, Attitudes, Practice , Health Personnel , Adolescent , Adult , Aged , Drug Utilization/standards , Female , Germany , Humans , Infection Control/methods , Male , Middle Aged , Surveys and Questionnaires , Young Adult
3.
Toxicol Lett ; 240(1): 122-9, 2016 Jan 05.
Article in English | MEDLINE | ID: mdl-26520184

ABSTRACT

In the present study, we explored the role of the aryl hydrocarbon receptor (AhR) for γ-H2AX associated DNA repair in response to treatment with ionizing radiation. Ionizing radiation was able to stabilize AhR protein and to induce a nuclear translocation in a similar way as described for exposure to aromatic hydrocarbons. A comparable AhR protein stabilization was obtained by treatment with hydroxyl-nonenal-generated by radiation-induced lipid peroxidation. AhR knockdown resulted in significant radio-sensitization of both A549- and HaCaT cells. Under these conditions an increased amount of residual γ-H2AX foci and a delayed decline of γ-H2AX foci was observed. Knockdown of the co-activator ARNT, which is essential for transcriptional activation of AhR target genes, reduced AhR-dependent CYP1A expression in response to irradiation, but was without effect on the amount of residual γ-H2AX foci. Nuclear AhR was found in complex with γ-H2AX, DNA-PK, ATM and Lamin A. AhR and γ-H2AX form together nuclear foci, which disappear during DNA repair. Presence of nuclear AhR protein is associated with ATM activation and chromatin relaxation indicated by acetylation of histone H3. Taken together, we could show, that beyond the function as a transcription factor the nuclear AhR is involved in the regulation of DNA repair. Reduction of nuclear AhR inhibits DNA-double stand repair and radiosensitizes cells. First hints for its molecular mechanism suggest a role during ATM activation and chromatin relaxation, both essential for DNA repair.


Subject(s)
Cell Survival/radiation effects , DNA Repair/radiation effects , Gamma Rays , Gene Expression Regulation , Receptors, Aryl Hydrocarbon/genetics , Receptors, Cytoplasmic and Nuclear/genetics , Acetylation , Animals , CHO Cells , Cell Line, Tumor , Cricetulus , DNA-Activated Protein Kinase/genetics , DNA-Activated Protein Kinase/metabolism , Hep G2 Cells , Histones/genetics , Histones/metabolism , Humans , Lamin Type A/genetics , Lamin Type A/metabolism , Lipid Peroxidation/radiation effects , Microscopy, Confocal , Receptors, Aryl Hydrocarbon/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Transcriptional Activation
4.
Phys Rev Lett ; 107(27): 275001, 2011 Dec 30.
Article in English | MEDLINE | ID: mdl-22243313

ABSTRACT

Unlike α- and γ-mode operation, electrons accelerated by strong drift and ambipolar electric fields in the plasma bulk and at the sheath edges are found to dominate the ionization in strongly electronegative discharges. These fields are caused by a low bulk conductivity and local maxima of the electron density at the sheath edges, respectively. This drift-ambipolar mode is investigated by kinetic particle simulations, experimental phase-resolved optical emission spectroscopy, and an analytical model in CF(4). Mode transitions induced by voltage and pressure variations are studied.

5.
Eat Disord ; 17(4): 273-92, 2009.
Article in English | MEDLINE | ID: mdl-19548145

ABSTRACT

This research evaluated attitudes about body image and eating in women practicing postural yoga. Study 1 described scores from questionnaires on variables related to body awareness, intuitive eating, spirituality, and reasons for practicing. Scores were favorable on all measures with significant correlations (p < .01) among all main variables except between spiritual readiness and intuitive eating, and between BMI and both body awareness and spiritual readiness. Reasons for practicing did not affect scores. Study 2 evaluated interviews in a sub-sample. Qualitative data reported improvements in body satisfaction and disordered eating due in part to yoga and its associated spirituality.


Subject(s)
Body Image , Feeding and Eating Disorders/psychology , Spirituality , Yoga , Adult , Attitude , Awareness , Female , Humans , Middle Aged , Personality Inventory , Self Concept , Surveys and Questionnaires , Young Adult
6.
Int J Radiat Biol ; 79(10): 801-8, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14630539

ABSTRACT

PURPOSE: To test a stimulatory effect of the radioprotector Bowman Birk protease inhibitor (BBI) upon DNA repair processes. MATERIALS AND METHODS: An effect of BBI upon DNA repair was investigated by quantification of radiation-induced dicentric chromosomes. Sensitivity to ionizing radiation was determined by clonogenic survival assay. Quantification of activity of the DNA-dependent kinase was performed by immunoprecipitation and phosphorylation of a TP53-derived peptide. RESULTS: The formation of radiation-induced dicentric chromosomes was reduced significantly after pretreatment of cells with BBI. By using a cell line with an inducible expression of a mutated TP53, it was shown that the BBI-mediated reduction of dicentric chromosome formation depended on the presence of wild-type TP53. To get further insights into the molecular mode of action of BBI, activity of the DNA-dependent protein kinase (DNA-PK) was quantified. BBI treatment resulted in a stimulation of basal (DNA-PK) activity. In SCID mouse fibroblasts deficient in DNA-PK activity, BBI failed to reduce the amount of radiation-induced dicentric chromosomes and the radioprotective effect was absent. Likewise, cells expressing mt.TP53 did not show radioprotection by BBI. CONCLUSIONS: It was observed that BBI exerts its radioprotective effect by a reduction of incorrect DNA repair, resulting in a reduced amount of dicentric chromosomes. This effect on the fidelity of DNA repair is TP53 dependent and correlated with induction of DNA-PK activity.


Subject(s)
Carcinoma, Bronchogenic/metabolism , Chromosome Aberrations/drug effects , DNA-Binding Proteins , Fibroblasts/metabolism , Fibroblasts/radiation effects , Protein Serine-Threonine Kinases/metabolism , Radiation-Protective Agents/pharmacology , Trypsin Inhibitor, Bowman-Birk Soybean/pharmacology , Tumor Suppressor Protein p53/metabolism , Carcinoma, Bronchogenic/genetics , Cell Line , Cell Survival/drug effects , Cell Survival/radiation effects , DNA-Activated Protein Kinase , Dose-Response Relationship, Radiation , Enzyme Activation/drug effects , Enzyme Activation/radiation effects , Enzyme Activators/pharmacology , Fibroblasts/drug effects , Lung Neoplasms/metabolism , Protein Serine-Threonine Kinases/drug effects , Radiation Dosage , Severe Combined Immunodeficiency/embryology , Severe Combined Immunodeficiency/genetics , Severe Combined Immunodeficiency/metabolism , Tumor Cells, Cultured , Tumor Suppressor Protein p53/drug effects
7.
Curr Med Chem Anticancer Agents ; 3(5): 360-3, 2003 Sep.
Article in English | MEDLINE | ID: mdl-12871082

ABSTRACT

Specific radioprotection of normal tissue represents a promising approach to improve radiotherapy. The ultimate feature of a normal tissue selective radioprotector is that tumor tissue is excluded from protection. Radioprotectors of the current generation, such as Ethyol, are not explicit normal tissue specific. In contrast, the Bowman Birk protease inhibitor, which is known to prevent in vitro and in vivo radiation-induced carcinogenesis, was found to be normal tissue specific. Moreover, the molecular restrictions for this specificity were identified. The radioprotective effect is dependent upon the presence of a functional wt. TP53. Since a high amount of tumors have lost TP53 function during tumor development, the clinical application of BBI to protect normal tissue from radiation damage would effectively improve the therapeutic outcome of radiation therapy. We succeeded to identify stimulation of DNA-repair mechanisms, such as nucleotide excision repair (NER) and nonhomologous end joining (NHEJ), as molecular mode of action. These results are in good agreement with the observations that BBI concomitantly exhibits anticarcinogenic effect and radioprotective effects. Taken together, BBI is recommended as a radioprotector for normal tissue expressing wild type TP53 during treatment of tumors characterized by a mutant TP53.


Subject(s)
Protease Inhibitors/pharmacology , Radiation-Protective Agents/pharmacology , Trypsin Inhibitor, Bowman-Birk Soybean/pharmacology , Animals , Fibroblasts/drug effects , Fibroblasts/physiology , Humans , Neoplasms/drug therapy , Neoplasms/enzymology , Neoplasms/radiotherapy , Protease Inhibitors/therapeutic use , Radiation-Protective Agents/therapeutic use , Trypsin Inhibitor, Bowman-Birk Soybean/chemistry , Trypsin Inhibitor, Bowman-Birk Soybean/therapeutic use , Tumor Suppressor Protein p53/metabolism
8.
Int J Radiat Biol ; 78(5): 331-9, 2002 May.
Article in English | MEDLINE | ID: mdl-12020424

ABSTRACT

PURPOSE: To study the role of transforming growth factor beta1 (TGF-beta1) on cellular radiation sensitivity by analysing mouse lung fibroblasts of different TGF-beta1 genotypes. MATERIALS AND METHODS: Heterozygous TGF-beta1 knock-out mice were mated to produce offspring of different TGF-beta1 genotypes as confirmed by PCR-genotyping. Primary lung fibroblast populations were established from new-born animals of specific genotypes (TGF-beta1(+/+), TGF-beta1(+/-), TGF-beta1(-/-)). Production of TGF-beta1 was tested by ELISA. TGF-beta1 receptor-II mRNA expression was analysed by RT-PCR. Colony formation of untreated, TGF-beta1-treated and/or irradiated primary lung fibroblasts was determined under different medium conditions. RESULTS: Plating efficiencies under different medium conditions were independent of TGF-beta1 genotype. Production of TGF-beta1 correlated with the genotype: heterozygous TGF-beta1 knock-out fibroblasts (TGF-beta1(+/-)) produced 60-65% of wild-type (TGF-beta1(+/+) cells). As expected, homozygous TGF-beta1 knock-out fibroblasts (TGF-beta1(-/-)) did not produce TGF-beta1. Radiation exposure significantly enhanced TGF-beta1 production in TGF-beta1(+/+) cells by a factor of 2. No such stimulation was observed in TGF-beta1(+/-) cells. TGF-beta1(+/-) and especially TGF-beta1(-/-) cells were significantly more radioresistant than TGF-beta1(+/+) cells. TGF-beta1 treatment significantly reduced clonogenic survival for both TGF-beta1(+/+) and TGF-beta1(-/-) cells. TGF-beta1 treatment of TGF-beta1(-/-) cells resulted in an enhancement of radiation sensitivity. CONCLUSION: The data are the first direct evidence that TGF-beta1 is a major autocrine regulator of intrinsic radiation sensitivity of mouse lung fibroblasts.


Subject(s)
Transforming Growth Factor beta/deficiency , Transforming Growth Factor beta/genetics , Activin Receptors, Type I/genetics , Animals , Cell Survival/drug effects , Cell Survival/radiation effects , Cells, Cultured , Colony-Forming Units Assay , Dose-Response Relationship, Radiation , Fibroblasts/cytology , Fibroblasts/metabolism , Fibroblasts/radiation effects , Genotype , Homozygote , Mice , Mice, Knockout , Protein Serine-Threonine Kinases , RNA, Messenger/genetics , RNA, Messenger/metabolism , Radiation Tolerance/drug effects , Radiation Tolerance/genetics , Radiation Tolerance/physiology , Receptor, Transforming Growth Factor-beta Type I , Receptors, Transforming Growth Factor beta/genetics , Reverse Transcriptase Polymerase Chain Reaction , Transforming Growth Factor beta/pharmacology , Transforming Growth Factor beta/physiology , Transforming Growth Factor beta1
9.
Radiat Environ Biophys ; 40(2): 163-7, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11484788

ABSTRACT

The Bowman-Birk proteinase inhibitor (BBI) has previously been described as a radioprotective agent against ionising radiation. It was demonstrated that BBI is able to significantly increase the clonogenic cell survival of normal fibroblasts when applied before exposure to ultraviolet B (UVB) radiation. In transformed TP53-mutated cell lines, however, the BBI-mediated radioprotection was absent. At the molecular level, the radioprotective effect of BBI can be correlated with BBI-mediated stabilisation of TP53 protein prior to irradiation. Following UVB irradiation, the BBI-treated cells present an accelerated removal of cyclobutane pyrimidine dimers. Thus, the cell and molecular biological data presented suggest that BBI is able to protect cells with functional TP53 from UVB-induced DNA damage. This protective effect is most likely achieved via the activation of the TP53 signalling cascade resulting in the activation of nucleotide excision repair.


Subject(s)
DNA Repair , Protease Inhibitors/pharmacology , Radiation Injuries/prevention & control , Tumor Suppressor Protein p53/metabolism , Blotting, Western , Cell Line, Transformed , Cells, Cultured , Dose-Response Relationship, Radiation , Fibroblasts/metabolism , Humans , Pyrimidine Dimers/chemistry , Signal Transduction , Time Factors , Ultraviolet Rays
10.
Protein Eng ; 14(3): 157-60, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11342711

ABSTRACT

The Bowman-Birk protease inhibitor has been reported to exert photo- and radioprotective activity. This effect was assigned to a cyclic nonapeptide sequence which is known to contain the amino acids responsible for the anti-chymotryptic activity of the BBI. The present study indicated that linearization of the nonapeptide resulted in a significant loss of anti-proteolytic activity, whereas the photo- and radioprotective capacity persisted. Substitution of the amino acids Leu or Ser of the nonapeptide, essential for the anti-proteolytic activity, with different amino acids, indicated that rather the hydrophobic features of the amino acids in this position than charge are critical to retain the photo- and radioprotective effect. These results suggest the existence of a bifunctional peptide sequence with anti-proteolytic and photo-/radioprotective capacity. However, the lack of correlation between the photo-/radioprotective activity and the anti-proteolytic activity within the peptides generated by modification of the linear nonapeptide argues for the existence of two closely colocalized domains within the nonapeptide responsible for photo-/radioprotection and protease inhibition.


Subject(s)
Amino Acids/chemistry , Fibroblasts/chemistry , Radiation-Protective Agents/chemistry , Serine Proteinase Inhibitors/metabolism , Skin/chemistry , Trypsin Inhibitor, Bowman-Birk Soybean/metabolism , Amino Acid Substitution , Cell Line , Clone Cells , Fibroblasts/cytology , Humans , Protein Structure, Secondary , Protein Structure, Tertiary , Radiation, Ionizing , Sequence Analysis, Protein , Serine Proteinase Inhibitors/chemistry , Skin/cytology , Structure-Activity Relationship , Ultraviolet Rays/adverse effects
11.
Int J Cancer ; 96 Suppl: 1-6, 2001.
Article in English | MEDLINE | ID: mdl-11992381

ABSTRACT

O-phospho-L-tyrosine (P-Tyr) has been reported previously to inhibit growth of several cancer cell lines at mM concentrations. In the present study, we investigated the effect of this compound on tumor cells and normal cells in combination with radiation exposure. It could be demonstrated for the first time that P-Tyr at microM concentrations protects TP53 wild-type cells against ionizing radiation (SF4 minus BBI = 0.28, SF4 plus BBI = 0.45). On the contrary, human transformed or tumor cell lines characterized by mutated or functional inactivated TP53 were not altered or increased in their radiation sensitivity (SF4 minus BBI = 0.32, SF4 plus BBI = 0.22). Treatment of wild-type TP53 cells with P-Tyr induced stabilization of TP53 within 3 and 16 hours and a subsequent increase in CDKN1A expression after treatment. Consequently, a 16-hours pretreatment of cells with P-Tyr led to a significant radioprotective effect. This was not observed in cell lines with mutated TP53, which shows no radioprotection by P-Tyr. Thus, the present data suggest that P-Tyr-mediated radioprotection is dependent on preirradiation stabilization of TP53. The results indicate that P-Tyr is a radioprotective agent that can potentially be very useful and easy to deliver for radiation protection in general and especially in radiation therapy of TP53-mutated tumors.


Subject(s)
Cyclins/metabolism , Mutation , Neoplasms/radiotherapy , Phosphotyrosine/therapeutic use , Radiation-Protective Agents/therapeutic use , Tumor Suppressor Protein p53/genetics , Blotting, Western , Cell Line, Transformed , Cell Survival , Cyclin-Dependent Kinase Inhibitor p21 , DNA, Complementary/metabolism , Dose-Response Relationship, Drug , Dose-Response Relationship, Radiation , Humans , Serine/metabolism , Threonine/metabolism , Time Factors , Tumor Cells, Cultured , Tumor Suppressor Protein p53/physiology
12.
Int J Radiat Biol ; 76(2): 223-9, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10716643

ABSTRACT

PURPOSE: The radioprotective effect of the Bowman-Birk protease inhibitor (BBI) was previously shown to result from a TP53 dependent mechanism. Whether this effect involves specific DNA repair mechanisms is now tested. MATERIAL AND METHODS: Normal human fibroblasts were pre-treated with BBI before exposure to X-rays, UVB or to chemical agents (bleomycin, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), cisplatin). These agents were chosen because of their ability to induce different spectra of DNA damage. The radiometric agent bleomycin primarily induces double-strand breaks (dsb), which are repaired by recombination; MNNG results in alkylated bases which are repaired by base excision repair (BER); cisplatin results in DNA-crosslinks which are repaired mainly by nucleotide excision repair (NER); and finally UVB generates thymine dimers and thymine-cytosine-6-4 products which are also repaired by NER. Cell survival was analysed by colony formation assay and DNA dsb by constant field gel electrophoresis. The combined effect of BBI and X-rays was also tested for XP-fibroblasts, which are defective in NER. RESULTS: For normal human fibroblasts the radioprotective effect of BBI was clearly found by using a delayed plating procedure. The radioprotective effect was found to be unrelated to an altered induction or repair of radiation-induced DNA dsb. Pretreatment with BBI did not affect cell killing after exposure to bleomycin or MNNG, but resulted in a significant protection of cells exposed to cisplatin or UVB. These results indicate that pre-treatment with BBI did not alter recombination repair or BER, but was able to modify NER. The latter finding was supported by the observation made for XP-cells, where pretreatment with BBI failed to result in radioprotection after exposure to ionizing radiation. CONCLUSIONS: On the basis of these data it is proposed that the radioprotective effect of BBI is the result of an improved nucleotide excision repair mechanism.


Subject(s)
DNA Repair/drug effects , Protease Inhibitors/pharmacology , Radiation-Protective Agents/pharmacology , Xeroderma Pigmentosum/genetics , Bleomycin/pharmacology , Cell Survival/drug effects , Cell Survival/radiation effects , Cells, Cultured , Cisplatin/pharmacology , Humans , Methylnitronitrosoguanidine/pharmacology , Ultraviolet Rays , X-Rays
13.
Anthropol Anz ; 58(4): 345-55, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11190928

ABSTRACT

Weaning age of the children of the early medieval population at Wenigumstadt (Ldkr. Aschaffenburg, southern Germany, 500-700 AD) was estimated by stable nitrogen isotope analysis of bone collagen. The onset of weaning was by one year of age, when solid vegetal food subsequently replaced breast milk. In total, the change from mother's milk to solid adult food took about three years, the infants being fully weaned at this age. While the growing infant was sufficiently supported in utero and during the first months of life, the weanling's diet was insufficient for further growth and development. Starting with about 18 months of age, more and more symptoms of malnutrition are detectable on the skeletal remains, and the peak of both morbidity and mortality is reached at four years of age. Especially unspecific stress markers like Harris' lines and enamel hypoplasia clearly indicate the infants' risk of falling ill or die between three and four years of age. Malnutrition weakens the immune response, therefore the majority of inflammations detectable on the skeleton are found among the inadequately nourished children. The assumption that weaning is responsible for pathological skeletal lesions and early death in history is thus supported by archaeometry.


Subject(s)
Infant Food/history , Infant Mortality , Protein-Energy Malnutrition/history , Weaning , Bone and Bones/pathology , Child, Preschool , Female , Germany , History, Medieval , Humans , Infant , Male , Paleopathology , Pregnancy
14.
Radiat Res ; 150(6): 648-55, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9840184

ABSTRACT

In the present study we have demonstrated that the Bowman-Birk proteinase inhibitor (BBI) protected normal fibroblasts from a radiation-induced reduction in cell survival, whereas in transformed fibroblasts no radioprotective effect was observed. It was shown that BBI reduced the radiation-induced protein stabilization and DNA-binding activity of TP53 (formerly known as p53) in normal fibroblasts. In transformed fibroblasts, BBI failed to induce these effects. The analysis of the TP53 gene in transformed fibroblasts revealed a mutation in exon 5. As a consequence of this mutation, the expression of the TP53 downstream gene CDKN1A (p21/WAF1/Cip1) is blocked. Based on experiments using TP53 antisense oligonucleotides, the radioprotective effect of BBI could be correlated with the function of wild-type TP53. Thus BBI can be considered as a selective radioprotective agent for normal human fibroblasts.


Subject(s)
Radiation-Protective Agents/pharmacology , Trypsin Inhibitor, Bowman-Birk Soybean/pharmacology , Tumor Suppressor Protein p53/metabolism , Base Sequence , Cell Cycle , Cell Line , Cell Line, Transformed , Colony-Forming Units Assay , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/genetics , DNA/drug effects , DNA/metabolism , DNA/radiation effects , DNA Damage , DNA Primers/genetics , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/radiation effects , Gene Expression/drug effects , Gene Expression/radiation effects , Genes, p53/radiation effects , Humans , Oligonucleotides, Antisense/pharmacology , Polymerase Chain Reaction , Polymorphism, Single-Stranded Conformational , Tumor Suppressor Protein p53/genetics
15.
Int J Radiat Biol ; 74(2): 225-30, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9712551

ABSTRACT

PURPOSE: To investigate the molecular mechanisms of the radioprotective effect of the Bowman-Birk proteinase inhibitor (BBI) in normal human skin fibroblasts (HSF). MATERIAL AND METHODS: The effect of BBI pre-treatment on p53 protein level and on mRNA levels of downstream genes (ERCC3, Gadd45 and p53) was investigated. RESULTS: As indicated by time-course experiments based on clonogenic assays, a 6 h pre-incubation with BBI before irradiation of HSF with a single dose of 6 Gy resulted in maximum radioprotection. In non-irradiated cells, pre-incubation with BBI resulted in an increased level of p53 protein. Concomitantly, enhanced mRNA levels of the ERCC3 and the Gadd45 genes were observed. As a consequence, BBI-treated cells showed accelerated DNA repair compared with untreated cells when irradiated. CONCLUSIONS: The radioprotective effect of the Bowman-Birk proteinase inhibitor was accompanied by elevated mRNA expression of repair-relevant genes prior to irradiation. Activation of the DNA-repair machinery induced by pre-treatment with BBI is one possible mechanism of the radioprotective effect of BBI.


Subject(s)
DNA Repair/genetics , Drosophila Proteins , Radiation-Protective Agents/pharmacology , Trypsin Inhibitor, Bowman-Birk Soybean/pharmacology , DNA-Binding Proteins/genetics , Fibroblasts , Gamma Rays/adverse effects , Humans , Intracellular Signaling Peptides and Proteins , Proteins/genetics , RNA, Messenger/drug effects , Signal Transduction/drug effects , Tumor Suppressor Protein p53/radiation effects , GADD45 Proteins
16.
Cancer Lett ; 125(1-2): 77-82, 1998 Mar 13.
Article in English | MEDLINE | ID: mdl-9566699

ABSTRACT

The Bowman-Birk protease inhibitor (BBI), a serine-protease inhibitor, has been reported to exert both anticarcinogenic and radioprotective activity. In this work we examined whether this effect is mediated through inhibition of serine-proteases of the trypsin-chymotrypsin type. Using linearized forms of BBI, evidence will be provided that the secondary structure, obligatory for the protease inhibitory function, is not necessary for the radioprotective effect. Detailed analysis indicated that the radioprotective effect is correlated with the chymotrypsin-inhibitory region of the molecule. Using a synthetic nonapeptide lacking protease inhibitor activity, the radioprotective effect of the total BBI molecule could be mimicked, indicating that the radioprotective effect is independent of the protease inhibitor function.


Subject(s)
Protein Structure, Secondary , Radiation-Protective Agents/pharmacology , Serine Proteinase Inhibitors/pharmacology , Antineoplastic Agents/pharmacology , Cells, Cultured , Humans , Serine Proteinase Inhibitors/chemistry , Structure-Activity Relationship
17.
Leuk Res ; 22(1): 49-53, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9585079

ABSTRACT

MK-886, a specific inhibitor of 5-lipoxygenase inhibited DNA replication in leukemic HL-60 cells in a dose-dependent manner. Addition of exogenous leukotriene B4 reversed this effect, whereas addition of leukotriene B4 failed to modulate a prostaglandin D2-induced inhibition of DNA replication. The reversal of MK-886-induced inhibition was not observed with leukotriene C4. These results suggest that the effect of MK-886 is mediated by inhibition of leukotriene B4 biosynthesis. Moreover, MK-886 not only impaired DNA replication in HL-60 cells but also decreased cell proliferation and induced apoptotic cell death. Our results suggest a crucial role of leukotriene B4 in the regulation of cell proliferation and cell survival in HL-60 cells.


Subject(s)
Apoptosis/drug effects , HL-60 Cells/pathology , Indoles/pharmacology , Leukotriene Antagonists , Lipoxygenase Inhibitors/pharmacology , Cell Division/drug effects , DNA Damage/drug effects , DNA Replication/drug effects , Humans
18.
Int J Radiat Biol ; 73(2): 157-62, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9489562

ABSTRACT

PURPOSE: To investigate the molecular action of the radioprotective Bowman Birk protease inhibitor (BBI) on radiation-induced tyrosine kinase activity. MATERIALS AND METHODS: Radiation-induced activation of tyrosine kinases and phosphatases was measured in normal human skin fibroblasts by in vitro kinase assays after pre-incubation with BBI. RESULTS: Pre-incubation with BBI resulted in a time-dependent block of the radiation-induced activation of tyrosine kinases. Whilst radiation-induced pp60c-Src activity was not modulated due to BBI pre-treatment, activation of epidermal growth factor receptor (EGFR) was inhibited. Additionally, pre-incubation with BBI resulted in enhanced tyrosine specific phosphatase (PTP) activity. CONCLUSIONS: BBI might exert its radioprotective activity by stabilizing specific tyrosine-phosphatases that interfere with EGFR activation in response to radiation exposure.


Subject(s)
ErbB Receptors/drug effects , ErbB Receptors/radiation effects , Protein Tyrosine Phosphatases/biosynthesis , Radiation-Protective Agents/pharmacology , Trypsin Inhibitor, Bowman-Birk Soybean/pharmacology , Enzyme Induction/drug effects , Enzyme Induction/radiation effects , Humans , Protein Tyrosine Phosphatases/drug effects , Protein Tyrosine Phosphatases/radiation effects
19.
Leukemia ; 10(9): 1520-6, 1996 Sep.
Article in English | MEDLINE | ID: mdl-8751473

ABSTRACT

92-kDa type IV collagenase/gelatinase (matrix metalloproteinase-9; MMP-9; gelatinase B) expression and secretion has been shown to correlate with the invasive and metastatic potential of various malignant cells. MMP activity is tightly controlled by specific tissue inhibitors of metalloproteinases (TIMPs). We found the leukemic cell line HL-60 constitutively to release a 94-kDa gelatinase which we identified as MMP-9 shortened by nine amino acids at its N-terminal end. An additional gelatinolytic activity was present in small amounts and identified as a 63-kDa fragment of MMP-9 generated by autocatalytical processing. Both enzymes were identical regarding their N-terminus, indicating C-terminal truncation for the former. Incubation of cells with phorbol ester resulted in elevated amounts of both enzymes in conditioned media and in the secretion of TIMP-1. Both gelatinases were shown to be activated by trypsin and organomercurials and to possess similar activities towards various substrates. However, the 63-kDa enzyme differed from the 94-kDa enzyme in a significantly reduced inhibition by recombinant TIMP-1 and TIMP-2. Thus, the 63-kDa fragment of MMP-9 once activated may escape the regulatory influence of its specific inhibitors and may thereby promote matrix degradation during invasion of leukemic cells.


Subject(s)
Collagenases/biosynthesis , Glycoproteins/pharmacology , HL-60 Cells/enzymology , Matrix Metalloproteinase Inhibitors , Peptide Fragments/antagonists & inhibitors , Peptide Fragments/biosynthesis , Proteins/pharmacology , Amino Acid Sequence , Catalysis , Collagenases/isolation & purification , Enzyme Activation , Glycoproteins/isolation & purification , HL-60 Cells/drug effects , Humans , Matrix Metalloproteinase 9 , Molecular Sequence Data , Peptide Fragments/isolation & purification , Sensitivity and Specificity , Substrate Specificity , Tetradecanoylphorbol Acetate/pharmacology , Tissue Inhibitor of Metalloproteinase-2 , Tissue Inhibitor of Metalloproteinases
20.
Exp Hematol ; 23(2): 155-60, 1995 Feb.
Article in English | MEDLINE | ID: mdl-7828672

ABSTRACT

In addition to the known 94-kd gelatinase (matrix metalloproteinase 9, MMP-9), HL-60 leukemia cells release a hither-to undescribed 45-kd metalloproteinase into the culture medium. This enzyme cleaves the synthetic substrate Pro-Gln-Gly-Ile-Ala-Gly-Gln-Arg, which represents the cleavage site for collagenases in collagen type I not between isoleucine and alanine--the typical cleavage site for collagenases--but between alanine and glycine. The enzymatic activity was purified through a combination of zinc-chelate-Sepharose column chromatography, precipitation with Fractogel TSK-AF Red and gelatin-Sepharose, and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Microsequence analysis of the NH2-terminus of the purified 45-kd proteinase revealed the sequence Asp-Ile-Ser-Lys-Tyr-Thr-Thr-Thr-, which could not be found in other proteins when searched in several protein data bases. Incubation of the enzyme immobilized on nitrocellulose membranes with polyclonal antibodies to collagenase and stromelysin or gelatinases revealed no cross-reactivity. The proteolytic activity was not increased by treatment with trypsin, 8M urea, acid, or organomercurials. The proteinase, which was inhibited by chemical inhibitors of metalloproteinases, such as phenanthrolene or EDTA, is able to degrade several matrix constituents, such as collagen type IV, fibronectin, gelatin, and proteoglycans. In contrast to all known MMPs, the proteolytic activity of the 45-kd enzyme was not abolished upon incubation with recombinant tissue inhibitors of matrix metalloproteinases (TIMP) 1 or 2. Thus, the novel enzyme may influence extracellular matrix (ECM) turnover in vivo because its activity is not influenced by specific inhibitors of MMPs.


Subject(s)
Extracellular Matrix/metabolism , Leukemia/enzymology , Metalloendopeptidases/metabolism , Amino Acid Sequence , Collagenases/metabolism , Glycoproteins/pharmacology , Humans , Matrix Metalloproteinase 9 , Metalloendopeptidases/antagonists & inhibitors , Metalloendopeptidases/isolation & purification , Molecular Sequence Data , Molecular Weight , Proteins/pharmacology , Tissue Inhibitor of Metalloproteinase-2 , Tissue Inhibitor of Metalloproteinases , Tumor Cells, Cultured
SELECTION OF CITATIONS
SEARCH DETAIL