Search PubMed⌕ Search

Biomedical subjects

I Hinberg

Publications and source records attributed to I Hinberg.

At least 37 records · Page 2Linked to original sources
PubMed1988

Degradation of explanted polyurethane cardiac pacing leads and of polyurethane.

Polyurethane cardiac pacing leads explanted at autopsy and from reoperated patients were examined for degradation in the insulation. Scanning electron microscopy (SEM) analysis showed cracks on the polyurethane surface which were both parallel and perpendicular to the longitudinal axis of the lead. Surface analyses of leads were performed using Fourier-Transform Infra-red (FT-IR) spectrophotometry in the attenuated total reflectance mode. The FT-IR spectra of visibly deteriorated polyurethane from explanted lead sheaths were compared with that of unused polyurethane tubing used for such sheaths. Changes were most evident in the regions of 3000-2800, 1730 and 1368 cm-1. The observed alterations in the FT-IR spectra were consistent with a degradation mechanism involving oxidative chain cleavage in the polyurethane amorphous regions. New polyurethane tubing (Pellethane-Type 80A) was exposed to sodium hypochlorite to simulate a possible in-vivo process and generate reference material. Degradation with associated decreases in tensile strength and molecular weight was recorded. This study showed that polyurethane insulation used in pacing leads is susceptible to oxidative degradation.

Biocompatible Materials↗
PubMed1988

A physician office analyzer. Evaluation of quality of results obtained by technical and nontechnical personnel.

We evaluated the Abbott Vision analyzer (Abbott Laboratories, North Chicago, Ill) both in a controlled laboratory setting and with several untrained individuals. We used control serum samples supplied by the manufacturer. Method comparison was performed with methods currently in use in our laboratory. The analytes evaluated were glucose, urea nitrogen, urate, cholesterol, triglycerides, and alkaline phosphatase. In the laboratory, the within-run precision (coefficient of variation) of all methods ranged from 0.8% to 3.4%; the range for between-run precision was 1.2% to 3.3%. Correlation between the Abbott Vision analyzer and routine methods was excellent. The upper limit of linearity for all methods was as stated by the manufacturer. The coefficient of variation obtained by ten nontechnical personnel ranged from 0.0% to 3.9%. The correlation between results obtained by the nontechnologist were excellent. Our study indicates the Abbott Vision analyzer is extremely easy to operate and provides reliable results in the hands of nontechnical personnel.

Allied Health Personnel↗
PubMed1988

Physician office analyzers. Do they satisfy medically useful criteria for analytical performance of laboratory tests?

The coefficients of variation (CVs) for several tests on physician office analyzers were compared with published data for medically useful criteria of these tests. Medically useful CVs were based on physicians' opinions of significant changes in laboratory tests. Precision studies using control material were carried out on four physician office analyzers by both a trained technologist and nontechnical personnel, such as physicians, nurses, and medical office personnel. This study was carried out during a six-month period. The instruments that were evaluated were the Reflotron, Seralyzer, Vision, and DT60. Low and high concentrations of quality control material, supplied by the manufacturer and those in use in the study laboratory (Omega I and II, Cooper Biomedical, Fairhaven, NJ), were used. With few exceptions, all instruments satisfied the medically useful CVs criteria, ie, the precision obtained by both the technologist and nontechnical personnel either equaled or exceeded the precision requirements set by physicians.

Autoanalysis↗
PubMed1987

Interference by cephalosporins with creatinine measurement by desk-top analyzers.

We have carried out a study to evaluate the interference by cephalosporins with the measurement of creatinine by desk-top analyzers. The cephalosporins evaluated at concentrations of 0-250 mg/l were cefazolin sodium, cefoxitin sodium, cefotaxime sodium, and ceftazidime pentahydrate. The instruments evaluated were DT60 (Kodak, Rochester, USA), Seralyzer (Ames Division, Miles Laboratories, IN, USA), and Vision (Abbott Labs, Chicago, USA). All studies were done in plasma. None of the cephalosporins showed any interference with the DT60 analyzer. With the Vision and Seralyzer no interference was seen with cefotaxime or cefazolin. With cefazolin an increase of 10-20 mumol/l creatinine was seen for every 20 mg/l of drug; with cefoxitin there was an increase of 50-80 mumol/l of creatinine for every 100 mg/l of drug. Erroneous creatinine values may be found in patients taking cefazolin and cefoxitin and may lead to inappropriate clinical management.

Cefazolin↗
PubMed1985

Aggregation of insulin, containing surfactants, in contact with different materials.

The aggregation of insulin and of insulin protected with surfactants was studied by shaking at 37 degrees C in glass, in polypropylene and polystyrene vials, and in CPI and Auto-Syringe insulin syringes and infusion sets. Surfactants such as Pluronic 17R8 and 25R5 hastened the aggregation, whereas Pluronic F68 was effective in preventing it. Furthermore, there was no change in the immunoreactivity of insulin containing Pluronic F68 even after 8 days of shaking. Unprotected insulin aggregated in all the vials. There appears to be little problem with the commercial syringes tested, but the infusion sets could cause aggregation of insulin if used over an extended period of time. Although Pluronic F68 prevented insulin aggregation in situ, it extracted more impurities from the contacting plastics. Further development in materials and design of insulin sets and insulin containers appears necessary.

Chemical Phenomena↗
PubMed1975

Preparation and kinetic properties of gel entrapped urate oxidase.

Urate oxidase from hog liver (urate: oxygen oxidoreductase, EC 1.7.33) has been entrapped in a crosslinked 2-hydroxyethyl methacrylate gel with a 47% retention of activity. The kinetic behavior of the gel entrapped enzyme has been studied in a slurried tank reactor using uric acid as substrate. Internal diffusion effects were found to be negligible for particle sizes below 128 mum. A threefold increase in Km (app) was observed for the 128 mum particles and attributed to diffusional effects. The pH activity profile of the gel entrapped enzyme was bell-shaped at high substrate concentration and could be fitted to a titration curve of two ionizable groups, a basic group having a pK of 7.9 and an acidic group with a pK of 11.0. The gel entrapped enzyme showed excellent stability between pH 6.5 and 10.5.

Adsorption↗