Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 13 de 13
Filter
1.
J Chromatogr A ; 1610: 460554, 2020 Jan 11.
Article in English | MEDLINE | ID: mdl-31597603

ABSTRACT

Therapeutic antibodies can elicit an immune response through different mechanisms, either cell independent via complement activation (CDC) or through activation of immune-effector cells (such as macrophages and NK cells). After target binding, the Fc part of the antibody will interact with Fc receptors on the surface of effector cells, leading to activation and lysis of the target cells by a mechanism called antibody-dependent cell-mediated cytotoxicity (ADCC). The ADCC of an antibody can be increased by modifying the carbohydrates on the Fc part. If the fucose on the first N-acetylglucosamine is absent, the affinity for the FcγRIIIa is increased and the ADCC enhanced. We describe the development of a chromatography method that is based on the differential affinity of the Fc receptor FcγRIIIa (high affinity V158 variant) for fucosylated and a-fucosylated antibodies. Immobilized FcγRIIIa can be used for the separation of immunoglobulins carrying these glycosylation variants for both, analytical and preparative purposes. The biological activity and fucose content of three pools enriched for fully fucosylated, mono-fucosylated or a-fucosylated carbohydrates could be characterized. Mono-fucosylated and a-fucosylated immunoglobulins have the same enhanced biological activity compared to fully fucosylated IgGs. A direct, label- and modification-free analytical method for screening of IgGs from culture supernatant was developed and was amenable to high-throughput screening. Clones producing antibodies with a high content of a-fucosylated oligosaccharides could be successfully selected.


Subject(s)
Antibodies/therapeutic use , Chromatography/methods , Fucose/metabolism , Protein Engineering , Receptors, IgG/metabolism , Amino Acid Sequence , Antibodies/chemistry , Antibody-Dependent Cell Cytotoxicity , Cells, Cultured , Glycosylation , Humans , Immunoglobulin G/metabolism , Oligosaccharides/metabolism , Receptors, IgG/chemistry
2.
Endoscopy ; 50(12): 1205-1234, 2018 12.
Article in English | MEDLINE | ID: mdl-30458567

ABSTRACT

This Position Statement from the European Society of Gastrointestinal Endoscopy (ESGE) and the European Society of Gastroenterology Nurses and Associates (ESGENA) sets standards for the reprocessing of flexible endoscopes and endoscopic devices used in gastroenterology. An expert working group of gastroenterologists, endoscopy nurses, chemists, microbiologists, and industry representatives provides updated recommendations on all aspects of reprocessing in order to maintain hygiene and infection control.


Subject(s)
Disinfection/methods , Disinfection/standards , Endoscopes/standards , Endoscopy, Gastrointestinal/instrumentation , Equipment Contamination/prevention & control , Infection Control/standards , Documentation/standards , Humans , Occupational Health/standards , Sterilization/methods , Sterilization/standards
3.
Clin Cancer Res ; 24(19): 4785-4797, 2018 10 01.
Article in English | MEDLINE | ID: mdl-29716920

ABSTRACT

Purpose: Despite promising clinical activity, T-cell-engaging therapies including T-cell bispecific antibodies (TCB) are associated with severe side effects requiring the use of step-up-dosing (SUD) regimens to mitigate safety. Here, we present a next-generation CD20-targeting TCB (CD20-TCB) with significantly higher potency and a novel approach enabling safer administration of such potent drug.Experimental Design: We developed CD20-TCB based on the 2:1 TCB molecular format and characterized its activity preclinically. We also applied a single administration of obinutuzumab (Gazyva pretreatment, Gpt; Genentech/Roche) prior to the first infusion of CD20-TCB as a way to safely administer such a potent drug.Results: CD20-TCB is associated with a long half-life and high potency enabled by high-avidity bivalent binding to CD20 and head-to-tail orientation of B- and T-cell-binding domains in a 2:1 molecular format. CD20-TCB displays considerably higher potency than other CD20-TCB antibodies in clinical development and is efficacious on tumor cells expressing low levels of CD20. CD20-TCB also displays potent activity in primary tumor samples with low effector:target ratios. In vivo, CD20-TCB regresses established tumors of aggressive lymphoma models. Gpt enables profound B-cell depletion in peripheral blood and secondary lymphoid organs and reduces T-cell activation and cytokine release in the peripheral blood, thus increasing the safety of CD20-TCB administration. Gpt is more efficacious and safer than SUD.Conclusions: CD20-TCB and Gpt represent a potent and safer approach for treatment of lymphoma patients and are currently being evaluated in phase I, multicenter study in patients with relapsed/refractory non-Hodgkin lymphoma (NCT03075696). Clin Cancer Res; 24(19); 4785-97. ©2018 AACR See related commentary by Prakash and Diefenbach, p. 4631.


Subject(s)
Antibodies, Bispecific/administration & dosage , Antibodies, Monoclonal, Humanized/administration & dosage , Hematologic Neoplasms/drug therapy , Rituximab/administration & dosage , Animals , Antigens, CD20/genetics , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Cell Line, Tumor , Disease Models, Animal , Gene Expression Regulation, Neoplastic/drug effects , Hematologic Neoplasms/immunology , Hematologic Neoplasms/pathology , Humans , Macaca fascicularis , Mice , T-Lymphocytes/drug effects , T-Lymphocytes/immunology
4.
Endoscopy ; 49(12): 1262-1275, 2017 Dec.
Article in English | MEDLINE | ID: mdl-29145674

ABSTRACT

1 Prerequisites. The clinical service provider should obtain confirmation from the endoscope washer-disinfector (EWD) manufacturer that all endoscopes intended to be used can be reprocessed in the EWD. 2 Installation qualification. This can be performed by different parties but national guidelines should define who has the responsibilities, taking into account legal requirements. 3 Operational qualification. This should include parametric tests to verify that the EWD is working according to its specifications. 4 Performance qualification. Testing of cleaning performance, microbiological testing of routinely used endoscopes, and the quality of the final rinse water should be considered in all local guidelines. The extent of these tests depends on local requirements. According to the results of type testing performed during EWD development, other parameters can be tested if local regulatory authorities accept this. Chemical residues on endoscope surfaces should be searched for, if acceptable test methods are available. 5 Routine inspections. National guidelines should consider both technical and performance criteria. Individual risk analyses performed in the validation and requalification processes are helpful for defining appropriate test frequencies for routine inspections.


Subject(s)
Disinfection/instrumentation , Disinfection/standards , Endoscopes/microbiology , Equipment Reuse/standards , Quality Control , Disinfection/methods , Documentation , Endoscopes/standards , Equipment Contamination/prevention & control , Guidelines as Topic , Validation Studies as Topic
5.
Endoscopy ; 49(11): 1098-1106, 2017 Nov.
Article in English | MEDLINE | ID: mdl-29036747

ABSTRACT

Patients should be informed about the benefits and risks of endoscopic retrograde cholangiopancreatography (ERCP)Only specially trained and competent personnel should carry out endoscope reprocessing.Manufacturers of duodenoscopes should provide detailed instructions on how to use and reprocess their equipment.In the case of modifications to their equipment, manufacturers should provide updated instructions for use.Detailed reprocessing protocols based on the manufacturer's instructions for use should clearly lay out the different reprocessing steps necessary for each endoscope model.Appropriate cleaning equipment should be used for duodenoscopes in compliance with the manufacturer's instructions for use. Only purpose-designed, endoscope type-specific, single-use cleaning brushes should be used, to ensure optimal cleaning. As soon as the endoscope is withdrawn from the patient, bedside cleaning should be performed, followed by leak testing, thorough manual cleaning steps, and automated reprocessing, in order to: · Remove debris from external and internal surfaces;. · Prevent any drying of body fluids, blood, or debris;. · Prevent any formation of biofilms.. In addition to the leak test, visual inspection of the distal end as well as regular maintenance of duodenoscopes should be performed according to the manufacturer's instructions for use, in order to detect any damage at an early stage.The entire reprocessing procedure in endoscope washer-disinfectors (EWDs) should be validated according to the European and International Standard, EN ISO 15883. Routine technical tests of EWDs should be performed according to the validation reports.Microbiological surveillance of a proportion of the department's endoscopes should be performed every 3 months, with the requirement that all endoscopes used in the unit are tested at least once a year.In the case of suspected endoscopy-related infection, the relevant device (e. g., endoscope, EWD) should be taken out of service until adequate corrective actions have been taken. Outbreaks should be managed by a multidisciplinary team, including endoscopy, hygiene, and microbiology experts, manufacturers, and regulatory bodies, according to national standards and/or laws. In the case of suspected multidrug-resistant organism (MDRO) outbreaks, close cooperation between the endoscopy unit and the clinical health provider is essential (including infection control departments and hospital hygienists).


Subject(s)
Cross Infection/prevention & control , Decontamination/methods , Decontamination/standards , Drug Resistance, Multiple , Duodenoscopes/standards , Equipment Contamination/prevention & control , Cross Infection/microbiology , Duodenoscopes/microbiology , Humans , Infection Control/methods
6.
Lab Chip ; 15(7): 1772-82, 2015 Apr 07.
Article in English | MEDLINE | ID: mdl-25687421

ABSTRACT

In this article we introduce and compare three techniques for low-cost and rapid bonding of stereolithographically structured epoxy components to polydimethylsiloxane (PDMS). In short, we first create a polysiloxane layer on the epoxy surface via silane surface coupling and polymerization. Afterwards, the modified epoxy surface can be bonded to a PDMS component at room temperature using a handheld corona discharger, which is a commonly used low-cost technique for bonding two PDMS components. Using these methods bonds of desirable strength can be generated within half an hour. Depending on the epoxy resin, we found it necessary to modify the silanization procedure. Therefore, we provide a total of three different silanization techniques that allow bonding of a wide variety of stereolithographically structurable epoxy resins. The first technique is a UV-light induced silanization process which couples a silane that contains an epoxy-ring ((3-glycidoxypropyl)trimethoxysilane (GPTMS)). For surfaces that cannot be modified with this silane we use dimethoxydimethylsilane (DMDMS). This silane can either be coupled to the surface by a sol-gel process or UV-light induced polymerisation. The sol-gel process which is a heat induced surface modification technique results in high bond strengths. Because of the heat which triggers the sol-gel process, this technique is limited to epoxy polymers with high glass transition temperatures. For the majority of stereolithographically structured epoxy resins which typically have glass transition temperatures of around 60 °C the light-induced bonding technique is preferable. For all three techniques we performed DIN EN-conform tensile testing demonstrating maximum bond strengths of up to 350 kPa which is comparable with bond strengths reported for PDMS-to-PDMS bonds. For all bond methods, long-term stability as well as hydrolytic stability was assessed.

7.
Lab Chip ; 14(15): 2698-708, 2014 Aug 07.
Article in English | MEDLINE | ID: mdl-24887072

ABSTRACT

Materials matter in microfluidics. Since the introduction of soft lithography as a prototyping technique and polydimethylsiloxane (PDMS) as material of choice the microfluidics community has settled with using this material almost exclusively. However, for many applications PDMS is not an ideal material given its limited solvent resistance and hydrophobicity which makes it especially disadvantageous for certain cell-based assays. For these applications polystyrene (PS) would be a better choice. PS has been used in biology research and analytics for decades and numerous protocols have been developed and optimized for it. However, PS has not found widespread use in microfluidics mainly because, being a thermoplastic material, it is typically structured using industrial polymer replication techniques. This makes PS unsuitable for prototyping. In this paper, we introduce a new structuring method for PS which is compatible with soft lithography prototyping. We develop a liquid PS prepolymer which we term as "Liquid Polystyrene" (liqPS). liqPS is a viscous free-flowing liquid which can be cured by visible light exposure using soft replication templates, e.g., made from PDMS. Using liqPS prototyping microfluidic systems in PS is as easy as prototyping microfluidic systems in PDMS. We demonstrate that cured liqPS is (chemically and physically) identical to commercial PS. Comparative studies on mouse fibroblasts L929 showed that liqPS cannot be distinguished from commercial PS in such experiments. Researchers can develop and optimize microfluidic structures using liqPS and soft lithography. Once the device is to be commercialized it can be manufactured using scalable industrial polymer replication techniques in PS--the material is the same in both cases. Therefore, liqPS effectively closes the gap between "microfluidic prototyping" and "industrial microfluidics" by providing a common material.


Subject(s)
Biocompatible Materials/chemistry , Fibroblasts/cytology , Microfluidic Analytical Techniques/instrumentation , Polystyrenes/chemistry , Animals , Biocompatible Materials/radiation effects , Cell Line , Cell Proliferation , Cell Survival , Dimethylpolysiloxanes/chemistry , Hot Temperature , Light , Materials Testing , Mice , Nitriles/chemistry , Phase Transition/radiation effects , Phosphines/chemistry , Phosphines/radiation effects , Photochemical Processes , Photosensitizing Agents/chemistry , Photosensitizing Agents/radiation effects , Polystyrenes/radiation effects , Printing, Three-Dimensional , Viscosity
8.
Lab Chip ; 13(22): 4343-51, 2013 Nov 21.
Article in English | MEDLINE | ID: mdl-24056989

ABSTRACT

In this paper we present a reusable, chemically inert, multichannel Chip-to-World-Interface (CWI). The concept of this interface is based on a force fit connection similar to the hollow screw connectors known from high-performance liquid chromatography (HPLC) instruments. It allows contamination free connection of up to 100 thermoplastic tubes to microfluidic chips made from various materials e.g., epoxy polymers, glass and polydimethylsiloxane (PDMS). The spacing of the tubes is fixed whereas the outer dimensions of the CWI can be adapted to the microfluidic chip it should be used with. We demonstrate that such a CWI with 100 tubes is pressure-tight up to (at least) 630 kPa (6.3 bar) pressure and the connection easily sustains flow rates above 4 ml min(-1). The presented CWI is designed such that the fluid probed in the microfluidic chip is in direct contact only with the tube material and the material from which the microfluidic chip is made. This not only enables fluid transport without dead volume, it also ensures that CWI itself will not be contaminated or contaminate the samples being probed. Using polytetrafluoroethylene (PTFE, Teflon®) tubing we demonstrate that the CWI can even be used with harsh organic solvents such as dichloromethane or dimethylformamide during continuous solvent probing over several hours without damage to the CWI or leakage. This CWI therefore effectively allows using almost all types of organic solvents in microfluidic applications.


Subject(s)
Microfluidic Analytical Techniques/instrumentation , Chromatography, High Pressure Liquid/instrumentation , Dimethylpolysiloxanes/chemistry , Glass/chemistry , Polytetrafluoroethylene/chemistry , Pressure , Solvents/chemistry
9.
Respiration ; 86(3): 229-36, 2013.
Article in English | MEDLINE | ID: mdl-23860465

ABSTRACT

BACKGROUND: Endobronchial ultrasound-transbronchial nee dle aspiration (EBUS-TBNA) is a useful technique for cytological assessment of enlarged mediastinal lymph nodes with a high diagnostic yield for lung cancer. However, the small sample volume can be problematic in diagnosing benign diseases and for molecular analysis of malignant tumours. OBJECTIVES: The aim of the study was to evaluate a novel lymph node forceps for EBUS-guided lymph node biopsy (EBUS-transbronchial forceps biopsy; EBUS-TBFB) in malignant and benign conditions concerning safety, feasibility, and diagnostic yield. METHODS: Patients with enlarged mediastinal or hilar lymph nodes were included. EBUS-TBNA was performed followed by EBUS-guided TBFB with the lymph node forceps. Three biopsy specimens were obtained. The diagnostic yields of EBUS-TBFB, EBUS-TBNA, and the combination of both sampling techniques were compared. Complications were systematically recorded. RESULTS: Fifty-five patients with enlarged mediastinal nodes were enrolled into this study. Specimens adequate for histological analysis were obtained in all but one case using EBUS-TBFB. EBUS-TBFB increased the diagnostic yield of EBUS-TBNA from 64 to 93% in benign conditions. The overall diagnostic yield was higher compared to EBUS-TBNA alone. EGFR mutation analysis could be achieved in the forceps biopsy samples as needed. No complications were observed. CONCLUSIONS: EBUS-TBFB with a novel lymph node forceps is safe and provides adequate histological specimens of enlarged mediastinal lymph nodes. EBUS-TBFB increases the diagnostic yield in benign conditions and may add value in molecular analysis of non-small cell lung cancer.


Subject(s)
Bronchoscopy/instrumentation , Endoscopic Ultrasound-Guided Fine Needle Aspiration/instrumentation , Lymph Nodes/pathology , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Mediastinum , Middle Aged , Prospective Studies , Young Adult
10.
Lab Chip ; 13(12): 2268-71, 2013 Jun 21.
Article in English | MEDLINE | ID: mdl-23645317

ABSTRACT

We describe a low cost, photo-induced, room-temperature bonding technique for bonding epoxy components to flexible PDMS membranes in less than half an hour. Bond strengths (~350 kPa) were characterized by ISO-conform tensile testing for a popular stereolithography resin and found comparable bond strengths as reported for PDMS/PDMS bonds.

11.
Best Pract Res Clin Gastroenterol ; 25(3): 371-85, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21764005

ABSTRACT

Since the 1960s quality assurance has become an integral part of medicine and nursing. The aims of quality assurance cover patient and staff safety and satisfaction, economical factors and the implementation of health care policy. Endoscopy units can be established in hospitals, primary care or ambulatory endoscopy centres. The quality of endoscopy facilities should be the same irrespective where endoscopy is carried out. Endoscopy staff is responsible for individualised, comprehensive patient care, technical assistance including reprocessing, documentation and management of endoscopy units. Quality criteria for endoscopy nursing cover pre, intra and post procedure care. However, a complete separation between clinical medical and nursing outcome criteria is often difficult in Endoscopy, as the clinical interventions are a combination of both medical and nursing actions. It is the combined effort of all staff with the support from the health care provider that leads to a high quality of patient care in Endoscopy.


Subject(s)
Endoscopy/nursing , Quality Assurance, Health Care , Endoscopy/standards , Humans
12.
Sci Total Environ ; 409(10): 1824-35, 2011 Apr 15.
Article in English | MEDLINE | ID: mdl-21349571

ABSTRACT

Many rivers and streams worldwide are impacted by pharmaceuticals originating from sewage. The hyporheic zone underlying streams is often regarded as reactive bioreactor with the potential for eliminating such sewage-born micropollutants. The present study aims at checking the elimination potential and analyzing the coupling of hydrodynamics, biogeochemistry and micropollutant processing. To this end, two sites at the lowland stream Erpe, which receives a high sewage burden, were equipped and sampled with nested piezometers. From temperature depth profiles we determined that at one of the sites infiltration of surface water into the aquifer occurs while exfiltration dominates at the other site. Biogeochemical data reveal intense mineralization processes and strictly anoxic conditions in the streambed sediments at both sites. Concentrations of the pharmaceuticals indomethacin, diclofenac, ibuprofen, bezafibrate, ketoprofen, naproxen and clofibric acid were high in the surface water and also in the subsurface at the infiltrating site. The evaluation of the depth profiles indicates some attenuation but due to varying surface water composition the evaluation of subsurface processes is quite complex. Borate and non-geogenic gadolinium were measured as conservative wastewater indicators. To eliminate the influence of fluctuating sewage proportions in the surface water, micropollutant concentrations are related to these indicators. The indicators can cope with different dilutions of the sewage but not with temporally varying sewage composition.


Subject(s)
Pharmaceutical Preparations/analysis , Rivers/chemistry , Water Pollutants, Chemical/analysis , Environmental Monitoring , Eutrophication , Hydrodynamics , Pharmaceutical Preparations/chemistry , Pharmaceutical Preparations/metabolism , Water Microbiology , Water Movements , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...