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1.
Phys Chem Chem Phys ; 19(7): 5405-5410, 2017 Feb 15.
Article in English | MEDLINE | ID: mdl-28164194

ABSTRACT

Carbon materials including carbon nanoparticles, such as nanographite, graphene and graphenic materials, and carbon nanotubes are known to be highly hydrophobic. Oxidation treatments are widely used as the best methods to improve their affinity in a liquid medium or a polymer matrix so that they can be dispersed, handled and processed. Here, we have applied eight different oxidation treatments in order to graft oxygen-containing functional groups at the surface of polyhedral graphitic particles synthesized by arc discharge from graphite, also called astralenes. The used functionalization approaches include both standard chemical attack by strong oxidants and radical functionalization of the sp2 network by direct C[double bond, length as m-dash]C bond opening. Commonly efficient functionalization methods were unsuccessful to functionalize astralenes while radicals generated from arylhydrazine could lead to functionalization of the outer surface of astralenes. The occurrence of functionalization could be shown by TGA coupled with MS and XPS. The reported method represents the first example of functionalization of astralenes. The efficiency of the applied functionalization methods is discussed considering the chemical reactivity of different carbon nanomaterials including graphene and carbon nanotubes.

2.
J Biomed Inform ; 66: 72-81, 2017 02.
Article in English | MEDLINE | ID: mdl-27993747

ABSTRACT

INTRODUCTION: Drug safety researchers seek to know the degree of certainty with which a particular drug is associated with an adverse drug reaction. There are different sources of information used in pharmacovigilance to identify, evaluate, and disseminate medical product safety evidence including spontaneous reports, published peer-reviewed literature, and product labels. Automated data processing and classification using these evidence sources can greatly reduce the manual curation currently required to develop reference sets of positive and negative controls (i.e. drugs that cause adverse drug events and those that do not) to be used in drug safety research. METHODS: In this paper we explore a method for automatically aggregating disparate sources of information together into a single repository, developing a predictive model to classify drug-adverse event relationships, and applying those predictions to a real world problem of identifying negative controls for statistical method calibration. RESULTS: Our results showed high predictive accuracy for the models combining all available evidence, with an area under the receiver-operator curve of ⩾0.92 when tested on three manually generated lists of drugs and conditions that are known to either have or not have an association with an adverse drug event. CONCLUSIONS: Results from a pilot implementation of the method suggests that it is feasible to develop a scalable alternative to the time-and-resource-intensive, manual curation exercise previously applied to develop reference sets of positive and negative controls to be used in drug safety research.


Subject(s)
Drug-Related Side Effects and Adverse Reactions , Electronic Data Processing , Knowledge Bases , Pharmacovigilance , Adverse Drug Reaction Reporting Systems , Humans
3.
Nervenarzt ; 88(11): 1273-1280, 2017 Nov.
Article in German | MEDLINE | ID: mdl-27638741

ABSTRACT

BACKGROUND: During the past years the provision of mental healthcare for adults with intellectual disabilities (ID) has repeatedly been criticized; however, the number of relevant studies is still relatively few. OBJECTIVE: The aim of the present study was to identify determinants for utilization of mental healthcare services and prescription of psychotropic medication in adults with mild to moderate ID. MATERIAL AND METHODS: Analyses were based on data from 417 adults with mild to moderate ID, which had been collected within the cross-sectional MEMENTA study in three different regions of Germany. Logistic regression analyses were conducted to identify clinical and sociodemographic variables as predictors of utilization of mental healthcare services (n = 282) and psychotropic medication (n = 351). RESULTS: Utilization of healthcare services and psychotropic medication were both associated with mental disorders and problem behavior. In addition, the likelihood of being treated with psychotropic medication and antipsychotic drugs was higher in adults living in residential homes. CONCLUSION: The findings indicate a lack of adherence to existing guidelines in the treatment of adults with ID living in residential homes.


Subject(s)
Intellectual Disability/drug therapy , Psychotropic Drugs/therapeutic use , Adult , Comorbidity , Cross-Sectional Studies , Drug Utilization/statistics & numerical data , Female , Germany , Humans , Intellectual Disability/classification , Intellectual Disability/epidemiology , Intellectual Disability/psychology , Male , Mental Disorders/classification , Mental Disorders/drug therapy , Mental Disorders/epidemiology , Mental Disorders/psychology , Middle Aged , Patient Acceptance of Health Care/psychology , Patient Acceptance of Health Care/statistics & numerical data , Problem Behavior/psychology , Statistics as Topic , Utilization Review/statistics & numerical data
4.
Nervenarzt ; 86(11): 1358-70, 2015 Nov.
Article in German | MEDLINE | ID: mdl-26384106

ABSTRACT

BACKGROUND: In mental healthcare the concept of pathways addresses diverse issues and problem areas, such as heterogeneous health service offers, the regional variability of treatment concepts and clear-cut guidelines on how and where to obtain treatment for a particular mental disorder. The ambiguous aspects of the concept require international and national definitions and consensus which must also cover quality criteria. METHODS: This article gives an overview of currently available evidence for the analysis of clinical pathways and pathways to care in international mental healthcare, covering studies on schizophrenia and depression from 2010 to 2014. RESULTS AND DISCUSSION: The ambiguity of the concept impedes the overview and does not provide unequivocal results. The development, implementation and analyses of guidelines or clear-cut clinical and pathways to care must consider individual, clinical and care system aspects as well as the interplay of these factors. Results suggest that system aspects tend to dominate over clinical factors of schizophrenia and depression. As a consequence, the definition, implementation and evaluation of clinical pathways or pathways to mental healthcare is first and foremost a responsibility of the respective national mental healthcare system and must be understood on that level, before findings are summarized internationally and models of best practice are debated.


Subject(s)
Critical Pathways/organization & administration , Depression/diagnosis , Depression/therapy , Psychotherapy/organization & administration , Schizophrenia/diagnosis , Schizophrenia/therapy , Depression/psychology , Evidence-Based Medicine , Germany , Humans , Schizophrenic Psychology , Treatment Outcome
6.
Clin Exp Immunol ; 173(2): 288-97, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23607690

ABSTRACT

2-Chlorodeoxyadenosine (cladribine, CdA) is an immunosuppressive drug that is licensed to treat hairy cell leukaemia, and has been shown recently to have beneficial effects in patients with multiple sclerosis (MS). The therapeutic effects of CdA have been suggested to be mediated partly through its potent toxicity towards lymphocytes. However, the effects of CdA on other immune cells are poorly understood. In the present study, we investigated the effects of CdA on the induction of apoptosis in human monocytes, monocyte-derived immature (ImDC) and mature (mDC) dendritic cells. Treatment of monocytes with CdA strongly induced apoptosis after 24 h, while apoptosis induction in DC was evident after 72 h. Furthermore, CdA treatment strongly induced caspase-3 and caspase-9 in monocytes, whereas activation of caspases was undetected in DC. The mitochondrial membrane potential in DC was reduced significantly after CdA treatment. DNA hypodiploid assessment showed fragmented nuclei in DC after CdA treatment together with activation of p53 protein. These results revealed that CdA induces caspase-independent apoptosis in DC and suggest cell type specific effects of CdA. This mechanism may contribute to the effect of CdA in autoimmune diseases.


Subject(s)
Cladribine/pharmacology , Dendritic Cells/drug effects , Immunosuppressive Agents/pharmacology , Leukemia, Hairy Cell/drug therapy , Monocytes/drug effects , Multiple Sclerosis/drug therapy , Apoptosis/drug effects , Caspase 3/genetics , Caspase 3/metabolism , Caspase 9/genetics , Caspase 9/metabolism , Cell Differentiation , Cells, Cultured , Cladribine/therapeutic use , DNA Damage/drug effects , Dendritic Cells/immunology , Humans , Membrane Potential, Mitochondrial/drug effects , Monocytes/immunology , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
7.
J Neuroimmunol ; 217(1-2): 46-50, 2009 Dec 10.
Article in English | MEDLINE | ID: mdl-19833395

ABSTRACT

In multiple sclerosis (MS) matrix metalloproteinases (MMP) are believed to be involved in the disruption of the blood brain barrier and demyelination. MMP-9 is increased in the cerebrospinal fluid of MS patients and expressed in MS lesions, indicating an involvement in MS pathogenesis. It is known that activated microglia secrete MMP. Modulation of MMP may thus be of interest for treatment in particular since MMP knock-out mice are less susceptible to experimental allergic encephalomyelitis. In this study we show that intact polyclonal immunoglobulins for intravenous use (IVIg) lead to increased secretion of MMP-9 in unstimulated microglia whereas F(ab')(2) fragments or stimulation with lipopolysaccharide (LPS) had no effect on MMP production at all. We could not detect MMP-2, MMP-3, MMP-7, MMP-10, MMP-11, and MMP-12 by RT-PCR with and without stimulation with LPS. IVIg differentially modulate MMP-9 production in resting and activated microglia suggesting an activation-dependent immune response.


Subject(s)
Gene Expression Regulation/drug effects , Immunoglobulins, Intravenous/pharmacology , Immunologic Factors/pharmacology , Matrix Metalloproteinase 9/metabolism , Microglia/drug effects , Analysis of Variance , Animals , Animals, Newborn , Brain/cytology , Cells, Cultured , Dose-Response Relationship, Drug , Humans , Lipopolysaccharides/pharmacology , Matrix Metalloproteinase 9/genetics , Microglia/enzymology , Nitric Oxide/metabolism , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Time Factors , Tumor Necrosis Factor-alpha/metabolism
8.
Z Gerontol Geriatr ; 37(5): 351-3, 2004 Oct.
Article in German | MEDLINE | ID: mdl-15503070

ABSTRACT

For the prevention and rehabilitation of fall-related fractures, not only functional status is important. It is necessary to describe the level of help and care needed at the time the fracture happened and its changes after a certain period. Investigations of the changes in the need of help and care after a fall-related fracture hardly exist for the Federal Republic of Germany. The first step in the present investigation was to analyze the changes in the need of help and care. In a second step, different developments of changes in the need of help and care after a fall-related hip fracture should be identified. Data for the present analysis were taken from a prospective 12-month observational survey (Fractures in late life). A total of 332 people aged 65 and over were assessed at two timepoints (T1-within the first 4 days post-fracture and T2-six months later by phone call). The assessed aspects were formal and informal support, financial support, ability to walk, cognition (only at T1) and form of housing. After the fall-related fracture the strain of formal and informal support increases. The strain of financial support and institutional care also increases. 20% of the patients achieved for the first time the criteria for the lowest level in the legal care system of Germany which indicates a higher level of need of care. 5% of the patients achieved post-fracture a higher level in the legal care system. Six different groups of patients could be identified by cluster analyses. They show differences in the changes in the ability to walk, form of housing, mortality and level of care and help. The different health status before and after the fall-related fracture leads to different developments post-fracture. In prevention and rehabilitation of patients with fall-related fractures, the individual needs of the subgroups should be taken into consideration.


Subject(s)
Activities of Daily Living , Aftercare/methods , Geriatric Assessment/methods , Geriatric Nursing/methods , Hip Fractures/epidemiology , Hip Fractures/nursing , Needs Assessment , Aftercare/statistics & numerical data , Aged , Aged, 80 and over , Female , Geriatric Nursing/statistics & numerical data , Germany/epidemiology , Hip Fractures/diagnosis , Hip Fractures/rehabilitation , Humans , Male , Old Age Assistance/statistics & numerical data , Patient Satisfaction , Residential Facilities/methods
9.
Zentralbl Chir ; 129 Suppl 1: S74-9, 2004 May.
Article in German | MEDLINE | ID: mdl-15168294

ABSTRACT

Almost 10 % of the population are concerned in the course of her life by chronic wounds, mortality resulting from this amount to 2.5 %. The Vacuum assisted closure (V.A.C.) therapy represents a modern procedure for the treatment of chronic wounds. Also in some first appearing offering no prospects cases hereby the Major amputation can be prevented and the majority of chronic therapy-resistant wounds can be healed. Due to first experiences with the V.A.C. therapy with the treatment of infected vascular grafts in the stage II and III after Szilágyi it also offers a success - promising option to concern the extremity and the life of the patient and to receive but also the infected graft in situ.


Subject(s)
Arterial Occlusive Diseases/surgery , Debridement/instrumentation , Ischemia/surgery , Leg/blood supply , Occlusive Dressings , Postoperative Complications/surgery , Suture Techniques/instrumentation , Varicose Ulcer/surgery , Venous Insufficiency/surgery , Aged , Aged, 80 and over , Amputation Stumps , Blood Vessel Prosthesis , Equipment Design , Humans , Microcomputers , Prosthesis-Related Infections/surgery , Reoperation/instrumentation , Surgery, Computer-Assisted/instrumentation , Surgical Wound Infection/surgery , Vacuum , Wound Healing/physiology
10.
Science ; 302(5651): 1727-36, 2003 Dec 05.
Article in English | MEDLINE | ID: mdl-14605208

ABSTRACT

Drosophila melanogaster is a proven model system for many aspects of human biology. Here we present a two-hybrid-based protein-interaction map of the fly proteome. A total of 10,623 predicted transcripts were isolated and screened against standard and normalized complementary DNA libraries to produce a draft map of 7048 proteins and 20,405 interactions. A computational method of rating two-hybrid interaction confidence was developed to refine this draft map to a higher confidence map of 4679 proteins and 4780 interactions. Statistical modeling of the network showed two levels of organization: a short-range organization, presumably corresponding to multiprotein complexes, and a more global organization, presumably corresponding to intercomplex connections. The network recapitulated known pathways, extended pathways, and uncovered previously unknown pathway components. This map serves as a starting point for a systems biology modeling of multicellular organisms, including humans.


Subject(s)
Drosophila Proteins/metabolism , Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Protein Interaction Mapping , Proteome , Animals , Calcium/metabolism , Cell Cycle , Cell Differentiation , Cloning, Molecular , Computational Biology , DNA, Complementary , Drosophila melanogaster/physiology , ErbB Receptors/metabolism , Genes, Insect , Immunity, Innate , Mathematics , Models, Statistical , Photoreceptor Cells, Invertebrate/cytology , Protein Binding , RNA Splicing , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction , Transcription, Genetic , Two-Hybrid System Techniques
11.
Unfallchirurg ; 106(3): 207-14, 2003 Mar.
Article in German | MEDLINE | ID: mdl-12658339

ABSTRACT

The goal of the investigation was to study case management and functional outcome in older patients with hip fracture. A prospective observational survey was performed, including all patients aged 65 years and over presenting with hip fracture in Heidelberg, from 1 July 1999 to 30 June 2000. All patients were reassessed by telephone calls 6 months post-fracture. A total of 331 patients were included (mean age 81.5 years, 81% female,23.8% nursing home residents). Hip fracture incidence per 1,000 was 7.8/year, and nursing home residents had a six times higher incidence rate than those living at home. Prior to the fracture, half of the patients were dependent in ambulation and a third needed support in basic activities. With substantial comorbidity (42% cognitive impairment), complications were common. Geriatric care was needed for 82% of the survivors. In-hospital treatment costs were about 10,000 Euro per fracture. Mortality at 6 months was 19.9%. The majority of survivors showed loss of competence and mobility. Functional outcome in older patients with hip fracture is disappointing. As the majority of the patients are frail, clinical treatment is complicated by "geriatric" problems. Thus, improved interdisciplinary care, with close cooperation between geriatricians and surgeons might result in a better functional outcome.


Subject(s)
Case Management , Hip Fractures/therapy , Age Factors , Aged , Aged, 80 and over , Chi-Square Distribution , Costs and Cost Analysis , Data Interpretation, Statistical , Female , Follow-Up Studies , Frail Elderly , Hip Fractures/economics , Hip Fractures/mortality , Hip Fractures/rehabilitation , Hip Fractures/surgery , Humans , Male , Nursing Homes , Prospective Studies , Risk Factors , Time Factors , Treatment Outcome
12.
Mol Immunol ; 38(1): 35-44, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11483208

ABSTRACT

Fab fragments derived from ten different IgG populations of hyperimmune rabbit polyclonal anti-fluorescein antibodies were further resolved into subfractions based on differences in time-dependent dissociation from an FITC-adsorbent in the presence of 0.1 M fluorescein at 4 degrees C. Fab fragments separated into subpopulations based on specific dissociation times of 0.1 day, 1.0 day, 10 days and 100 days from the adsorbent. Finally, after the 100 days elution step incubation with 6.0 M guanidine-HCl was included to determine total protein concentration of specific anti-fluorescein Fab fragments. Yields of specifically eluted Fab fragments ranged from 12.7 to 84.1% of the total Fab population originally incubated with the adsorbent. All Fab polyclonal populations and subpopulations analyzed quenched the fluorescence of the bound ligand by 90% or greater. None of the plots of protein concentration versus percent yield of the total specific antibody obtained for each of the five resolved fractions constituting a specific polyclonal population conformed to Gaussian distributions. All resolved Fab subpopulations retained bound fluorescein ligand that exhibited significant bathochromic shifts in absorbancy. Based on the extent of the red-shift the antibodies segregated into one of two general spectral families showing either a peak shift to 505-507 nm or to 518-520 nm. The red-shift to 518-520 nm appeared unique to rabbit anti-fluorescein antibodies, since corresponding large shifts have not been observed with antibodies derived from other species (e.g. mouse, rat, chicken, etc.). K(d) values determined for the resolved fractions confirmed a continuous progression in affinity from the 0.1day through the 100 days elution. Preliminary isoelectric focusing analyses revealed progressive selection for relatively more homogeneous fractions, especially in the 100 days resolved fraction.


Subject(s)
Antibody Affinity/immunology , Fluorescein , Immunoglobulin Fab Fragments/immunology , Animals , Chemical Fractionation , Female , Isoelectric Focusing , Ligands , Rabbits , Time Factors
13.
Vasa ; 30(2): 132-4, 2001 May.
Article in German | MEDLINE | ID: mdl-11417285

ABSTRACT

The unilateral distal arterial lesions still give problems in classification and differential diagnosis specially in younger patients. We report on a 45 years old male patient with an aneurysm of the distal ulnar artery and superficial palmar arch. The chronic occupational trauma of the artery led to the clinical picture of hypothenar hammer syndrome.


Subject(s)
Accidents, Occupational , Aneurysm/surgery , Cumulative Trauma Disorders/surgery , Hand Injuries/surgery , Hand/blood supply , Ulnar Artery/injuries , Aneurysm/diagnostic imaging , Angiography , Cumulative Trauma Disorders/diagnostic imaging , Diagnosis, Differential , Hand Injuries/diagnostic imaging , Humans , Male , Middle Aged , Ulnar Artery/diagnostic imaging , Ulnar Artery/surgery
15.
Mol Immunol ; 37(6): 311-20, 2000 Apr.
Article in English | MEDLINE | ID: mdl-11000404

ABSTRACT

Extensive documentation shows that macrophage efficiently present antigen to CD 4(+) T-cells in conjunction with the MHC II molecule. Previously, a novel fluorescent probe, FITC-BSA, was developed to analyze intracellular antigen processing and presentation pathways within viable peritoneal murine macrophage. The studies revealed fluorescein's accessibility to antibody binding when associated with peptides bound within the MHC II cleft. To determine if MHC II-fluoresceinated-peptide complexes on the surface of macrophage were also sufficient to stimulate antigen-specific B-cells, nylon wool-purified splenic B-cells from FITC-KLH injected BALB/c mice (H-2(d)) were co-cultured with antigen-pulsed macrophage. B-cell stimulation and antibody production was observed in the presence of FITC-BSA-pulsed macrophage, whereas, macrophage incubated in the presence of unlabeled BSA were not stimulated. Compared with control cells, similar levels of stimulation were detected following depletion of Thy 1.2(+) cells from nylon wool-based spleen cell preparations. Stimulation was inhibited upon preincubation with anti-fluorescein IgG antibodies. Stimulation was not measurable using B-cells derived from the naive mice. The interaction was inhibited upon addition of MHC II specific antibodies and leupeptin, a microbial product that inhibits MHC II-peptide complex formation. Importantly, antibody production was not observed in the presence of antigen-pulsed macrophage from H-2(b) mice. Moreover, B-cell stimulation via this pathway was dependent upon antigen concentration as well as the cell to cell ratio.


Subject(s)
Antigen Presentation , B-Lymphocytes/immunology , Macrophages/immunology , Animals , Antibody Formation , Antigens/administration & dosage , B-Lymphocytes/drug effects , Cattle , Cell Membrane/immunology , Fluorescein-5-isothiocyanate/analogs & derivatives , Fluorescent Dyes , H-2 Antigens/metabolism , In Vitro Techniques , Lymphocyte Activation , Mice , Mice, Inbred BALB C , Mitomycin/pharmacology , Serum Albumin, Bovine
16.
Biochem Biophys Res Commun ; 275(3): 955-61, 2000 Sep 07.
Article in English | MEDLINE | ID: mdl-10973827

ABSTRACT

Bis-(8-anilinonaphthalene-1-sulfonate) (bis-ANS) causes inactivation of vesicular stomatitis virus (VSV) at micromolar concentrations while butyl-ANS and ANS are effective at concentrations one and two orders of magnitude higher, respectively. VSV fully inactivated by the combined effects of 10 microM bis-ANS and 2.5 kbar hydrostatic pressure elicited a high titer of neutralizing antibodies. Incubation of VSV with >/=2 M urea at atmospheric pressure caused very little virus inactivation, whereas at a pressure of 2.5 kbar, 1 M urea caused inactivation that exceeded by more than two orders of magnitude the sum of the inactivating effects produced by urea and pressure separately. Measurements of bis-ANS fluorescence showed that increasing the urea concentration reduces the pressure required to disrupt the structure. We conclude that anilinonaphthalene sulfonate compounds inactivate VSV by a mechanism similar to that produced by pressure. The most effective antiviral compound was bis-ANS which can be used for the preparation of safe viral vaccines or as an antiviral drug eventually.


Subject(s)
Anilino Naphthalenesulfonates/pharmacology , Vesicular stomatitis Indiana virus/drug effects , Anilino Naphthalenesulfonates/chemistry , Anilino Naphthalenesulfonates/metabolism , Anilino Naphthalenesulfonates/therapeutic use , Animals , Antibodies/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Cell Line , Cricetinae , Dose-Response Relationship, Drug , Fluorescence , Hydrostatic Pressure , Serum Albumin/pharmacology , Urea/pharmacology , Vesicular stomatitis Indiana virus/immunology , Vesicular stomatitis Indiana virus/physiology , Xylose/pharmacology
17.
Scanning ; 22(4): 249-57, 2000.
Article in English | MEDLINE | ID: mdl-10958392

ABSTRACT

Cell behavior is three-dimensional (3-D), even when it takes place on a flat surface. Migrating cells form pseudopods on and off the substratum, and the cell body undergoes height changes associated with a 1 min behavior cycle. Inside the cell, the nucleus has a 3-D migratory cycle, and vesicles move up and down in the z-axis as a cell locomotes. For these reasons, the two-dimensional (2-D) analysis of cellular and subcellular behavior is, in many cases, inadequate. We have, therefore, developed 3-D motion analysis systems that reconstruct the cell surface, nucleus, pseudopods, and vesicles of living, crawling cells in 3-D at time intervals as short as 1 s, and compute more than 100 parameters of motility and dynamics morphology at 1-s intervals. We are now in the process of developing a multimode reconstruction system that will allow us to reconstruct and analyze fluorescently tagged molecular complexes within the differential interference contrast-imaged subcellular architecture of a crawling cell. These evolving technologies should find wide application for a host of biomedical problems.


Subject(s)
Cell Movement , Dictyostelium/physiology , Dictyostelium/ultrastructure , Image Processing, Computer-Assisted , Microscopy, Interference/instrumentation , Microscopy, Phase-Contrast/instrumentation , Animals , Cell Membrane/physiology , Cell Membrane/ultrastructure , Cell Nucleus/physiology , Cell Nucleus/ultrastructure , Microscopy, Interference/methods , Microscopy, Phase-Contrast/methods , Organelles/physiology , Organelles/ultrastructure , Pseudopodia/physiology , Pseudopodia/ultrastructure , Software , User-Computer Interface
18.
Appl Biochem Biotechnol ; 83(1-3): 95-103; discussion 103-5, 145-53, 2000.
Article in English | MEDLINE | ID: mdl-10826952

ABSTRACT

Monoclonal anti-DNA autoantibody BV 04-01 catalyzed hydrolysis of DNA in the presence of Mg2+. Catalysis was associated with BV 04-01 IgG, Fab, and single-chain-antibody (SCA) proteins. Cleavage of both ss and dsDNA was observed with efficient hydrolysis of the C-rich region of A7C7ATATAGCGCGT2, as well as a preference for cleaving within CG-rich regions of dsDNA. Data on specificity of ssDNA hydrolysis and kinetic data obtained from wild-type SCA, and two SCA mutants were used to model the catalytically active antibody site using the previously resolved X-ray structure of BV 04-01. The resulting model suggested that the target phosphodiester bond is activated by induction of conformational strain. In addition, the antibody-DNA complex contained a Mg2+ coordination site composed of the L32Tyr and L27dHis side chains and a DNA 3'-phosphodiester group. Induction of strain along with the metal coordination could be part of the mechanism by which this antibody catalyzes DNA hydrolysis. Sequence data for BV 04-01 V(H) and V(L) genes suggested that the proposed catalytic-antibody active site was germline-encoded. This observation suggests that catalytic activity might represent an important-rarely examined-function for some antibody molecules.


Subject(s)
Antibodies, Antinuclear/metabolism , Antibodies, Catalytic/metabolism , Antibodies, Monoclonal/metabolism , DNA/immunology , DNA/metabolism , Animals , Antibodies, Antinuclear/chemistry , Antibodies, Antinuclear/genetics , Antibodies, Catalytic/chemistry , Antibodies, Catalytic/genetics , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/genetics , Base Sequence , Binding Sites , DNA/chemistry , Hydrolysis , In Vitro Techniques , Kinetics , Mice , Models, Molecular , Mutation , Protein Conformation
19.
J Appl Physiol (1985) ; 88(2): 804-10, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10658054

ABSTRACT

In a previous study, we demonstrated that exhaustive exercise suppressed peritoneal macrophage antigen presentation (AP). In this study, we explored the intracellular mechanism(s) responsible for this suppression. Pathogen-free male BALB/c mice (8 +/- 2 wk) were randomly assigned to either home cage control (HCC) or exhaustive exercise stress (Exh, 18-30 m/min for 3 h/day) treatment groups. The mice underwent treatments for a period of 4 days during induced peritoneal thioglycollate inflammation. Elicited macrophages were harvested, purified, and incubated with chicken ovalbumin (C-Ova, 2. 5 and 10 mg/ml) for 18 h. After macrophages were washed, they were cocultured with C-Ova-specific T cells for 48 h at which time the supernates were harvested and analyzed via ELISA for interleukin (IL)-2 as an indication of macrophage AP. There was no significant (P > 0.05) difference in macrophage AP between cells fixed with paraformaldehyde vs. those that remained unfixed, suggesting that Exh did not affect production of soluble factors influencing macrophage AP (i.e., IL-1, IL-4, PGE(2)). The ability of macrophages to generate C-Ova immunogenic peptides was analyzed using FITC-labeled C-Ova, which shows fluorescence only when degraded intracellularly. There was a significant ( approximately 20%, P < 0. 05) suppression in fluorescence in the Exh compared with HCC, indicating a possible defect in the ability of macrophages from Exh to degrade C-Ova into immunogenic peptides. Macrophages were also incubated with C-Ova immunogenic peptide in a manner identical to that for native C-Ova. We found a similar suppression ( approximately 22-38%, P < 0.05) in macrophage AP using a C-Ova peptide when compared with native C-Ova in the Exh group, indicating reduced major histocompatibility complex (MHC) II loading and/or C-Ova-MHC II complex cell surface expression. In conclusion, these data indicate an intracellular defect in the macrophage antigen processing pathway induced by Exh.


Subject(s)
Antigen Presentation , Macrophages, Peritoneal/immunology , Physical Conditioning, Animal/physiology , Animals , Antigen-Presenting Cells/cytology , Antigen-Presenting Cells/immunology , Chickens , Coculture Techniques , Culture Media, Conditioned/chemistry , Dose-Response Relationship, Drug , Interleukin-2/metabolism , Macrophages, Peritoneal/cytology , Macrophages, Peritoneal/drug effects , Male , Mice , Mice, Inbred BALB C , Ovalbumin/immunology , Ovalbumin/metabolism , Ovalbumin/pharmacology , Specific Pathogen-Free Organisms , T-Lymphocytes/cytology , T-Lymphocytes/drug effects , T-Lymphocytes/metabolism
20.
J Cell Sci ; 113 ( Pt 1): 21-36, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10591622

ABSTRACT

Although the traditional role of clathrin has been in vesicle trafficking and the internalization of receptors, a novel role in cytokinesis was recently revealed in an analysis of a clathrin-minus Dictyostelium mutant (chc(-)). chc(-) cells grown in suspension were demonstrated to be defective in assembling myosin II into a normal contractile ring. To test whether this defect reflected a more general one of cytoskeletal dysfunction, chc(-) cells were analyzed for cell polarity, pseudopod formation, uropod stability, cell locomotion, chemotaxis, cytoskeletal organization and vesicle movement. chc(-) cells crawled, chemotaxed, localized F-actin in pseudopods, organized their microtubule cytoskeleton in a relatively normal fashion and exhibited normal vesicle dynamics. Although chc(-) cells extended pseudopods from the anterior half of the cell with the same frequency as normal chc(+) cells, they extended pseudopods at twice the normal frequency from the posterior half of the cell. The uropods of chc(-) cells also exhibited spatial instability. These defects resulted in an increase in roundness, a reduction in polarity, a reduction in velocity, a dramatic increase in turning, a high frequency of 180 degrees direction reversals and a decrease in the efficiency of chemotaxis. All defects were reversed in a rescued strain. These results are the first to suggest a novel role for clathrin in cell polarity, pseudopod formation, uropod stability and locomotion. It is hypothesized that clathrin functions to suppress pseudopod formation and to stabilize the uropod in the posterior half of a crawling cell, two behavioral characteristics that are essential for the maintenance of cellular polarity, efficient locomotion and efficient chemotaxis.


Subject(s)
Cell Movement , Cell Polarity , Clathrin/metabolism , Dictyostelium/cytology , Pseudopodia/metabolism , Actins/metabolism , Animals , Cell Size , Chemotaxis , Clathrin/genetics , Cyclic AMP/metabolism , Dictyostelium/genetics , Dictyostelium/physiology , Gene Deletion , Kinetics , Microtubules/metabolism
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