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Biomedical subjects

C Coester

Publications and source records attributed to C Coester.

9 recordsLinked to original sources
PubMed2004

Incorporation of biodegradable nanoparticles into human airway epithelium cells-in vitro study of the suitability as a vehicle for drug or gene delivery in pulmonary diseases.

PURPOSE: Nanoparticles are able to enhance drug or DNA stability for purposes of optimised deposition to targeted tissues. Surface modifications can mediate drug targeting. The suitability of nanoparticles synthesised out of porcine gelatin, human serum albumin, and polyalkylcyanoacrylate as drug and gene carriers for pulmonary application was investigated in vitro on primary airway epithelium cells and the cell line 16HBE14o-. METHODS: The uptake of nanoparticles into these cells was examined by confocal laser scan microscopy (CLSM) and flow cytometry (FACS). Further the cytotoxicity of nanoparticles was evaluated by an LDH-release-test and the inflammatory potential of the nanoparticles was assessed by measuring IL-8 release. RESULTS: CLSM and FACS experiments showed that the nanoparticles were incorporated into bronchial epithelial cells provoking little or no cytotoxicity and no inflammation as measured by IL-8 release. CONCLUSIONS: Based on their low cytotoxicity and the missing inflammatory potential in combination with an efficient uptake in human bronchial epithelial cells, protein-based nanoparticles are suitable drug and gene carriers for pulmonary application.

Biodegradation, Environmental↗
PubMed2000

Preparation of avidin-labelled gelatin nanoparticles as carriers for biotinylated peptide nucleic acid (PNA).

The possibility of preparing uniform nanoparticles consisting of proteins such as gelatin followed by covalent linkage of avidin was investigated. Gelatin nanoparticles were prepared by two step desolvation. Functional groups at the surface of the particulate system were quantified with site-specific reagents. The surface of the nanoparticles was thiolated and avidin was covalently attached to the nanoparticles via a bifunctional spacer at high levels. Biotinylated peptide nucleic acid (PNA) was effectively complexed by the avidin-conjugated nanoparticles. Avidin-conjugated protein nanoparticles should prove as potential carrier system for biotinylated drug derivatives in antisense therapy.

Avidin↗
PubMed2000

Desolvation process and surface characterisation of protein nanoparticles.

The objective of the present study was to characterise and optimise the desolvation process of human serum albumin (HSA) for the preparation of nanoparticles and to characterise the resulting colloidal system. Following the desolvation of the protein, the resulting nanoparticles were stabilised by the addition of varying amounts of glutaraldehyde or by heat denaturation. The particle size, zeta potential, and the number of available amino groups on the surface of the nanoparticles were determined. The amino groups were quantified by a spectrophotometric method using 2,4, 6-trinitrobenzenesulfonic acid (TNBS). The results indicated that the particle size depended mainly on the amount of desolvating agent added, but not on the amount of cross-linker or the kind of cross-linking procedure. Increasing amounts of glutaraldehyde reduced the number of amino groups on the surface of HSA nanoparticles and also decreased the zeta potential of the carrier system. The temperature and heat denaturation time only had an influence on the stability of the nanoparticles but not on the amount of amino groups or the particle size. It was shown that heat denatured HSA nanoparticles possessed the greatest number of amino groups on their surface. Additional experiments for the characterisation of gelatin A and B nanoparticles were performed.

Colloids↗
PubMed2000

Preparation of avidin-labeled protein nanoparticles as carriers for biotinylated peptide nucleic acid.

The possibility of preparing protein nanoparticles followed by covalent linkage of avidin was investigated. Free sulfhydryl groups were introduced onto the surface of protein nanoparticles either by aldehyde quenching with cysteine or reaction of free amino groups with 2-iminothiolane. The number of primary amino groups and sulfhydryl groups on the surface of the resulting particles was quantified with site-specific reagents. Avidin was attached to the surface of the thiolated nanoparticles via a bifunctional spacer which reacted in a first step with amino groups of avidin and in a second step with the sulfhydryl groups introduced onto the surface of the nanoparticles. Biotinylated peptide nucleic acid (PNA) as a model compound for biotinylated drugs was effectively coupled to the nanoparticles by complex formation with the covalently attached avidin. Since the formation of the interaction between biotin and avidin is very rapid and stable a highly effective drug carrier system for biotinylated compounds such as PNAs was achieved.

Avidin↗
PubMed1996

[Anterior high-frequency capsulotomy: advantages and problems].

METHODS: Since the clinical test phase, the author performed consistently more than 500 capsulotomies in his cataract surgeries by means of a radio-frequency current, using an instrument developed by Klöti et al. Some problems in the application of the instrument and their possible solution are discussed from the practical view of the user. CONCLUSIONS: The method proved as easy and safe to use especially in certain difficult cases. The main problem seems to be a reduced stability of the anterior capsular rim compared to the cases performed by capsulorhexis.

Cataract Extraction↗
PubMed1992

[Anterior high frequency capsulotomy. II. Clinico-surgical experiences].

Using an instrument developed by Klöti, the author performed anterior capsulotomy by means of a radio-frequency current in 21 cases of extracapsular cataract extraction. This group is compared with 21 control cases. The advantages and limits of this technique are discussed. The procedure was found to be simple and very helpful to the surgeon. There was no evidence of any damage to structures in the patient's eye.

Cataract Extraction↗
PubMed1991

[Computer as replacement for the current medical record? Introduction of a pilot project of the St. Gallen ophthalmology clinic].

Computerized data processing is more and more used in hospitals and medical offices. There are no doubts about the usefulness of a computer for administrative tasks. At our Dept. of Ophthalmology we started a pilot project to enter the medical records into the computer. The pros and cons of such an information system are discussed. Entering medical records into the computer did not prove to be definite advantage for the physician.

Computer Systems↗
PubMed1987

[Unusual cases of coronary death].

Stenosing coronary artery sclerosis is the most common cause of sudden unexpected death. In this report we present three exceptions: 1. A mycotic coronary aneurysm ruptures and results in pericardial tamponade; 2. in a young woman Takayasu aortitis encroaches on the ostium and mainstem of the left coronary; 3. fibromuscular dysplasia of the right coronary artery causes death in a 56-year-old male.

Adult↗