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Biomedical subjects

O Vesterberg

Publications and source records attributed to O Vesterberg.

At least 73 records · Page 4Linked to original sources
PubMed1984

Two-dimensional electrophoresis of proteins in human serum: improved resolution by use of narrow pH gradients and prolonged electrophoresis.

The limited resolution of serum proteins achieved with a simplified technique of two-dimensional electrophoresis (Clin. Chim. Acta 103: 51-59, 1980) has been improved by using different ampholyte (Ampholine) mixtures in the first dimension, to obtain relatively shallow pH gradients, and prolonged electrophoresis time in the second dimension. The technique has been further simplified, without negative effect, by decreasing the concentration of non-ionic detergent (first dimension), omitting both sodium dodecyl sulfate equilibration and the use of a stacking gel (second dimension), and by using an improved silver-staining procedure. Reverse-polarity isoelectric focusing and non-equilibrium pH-gradient electrophoresis have been successfully used to resolve the basic polypeptides in serum after deleting sodium dodecyl sulfate from the sample preparation. These combined techniques reveal over 1100 polypeptides in human serum. After immunodeletion of albumin, additional serum polypeptides are seen. Immunodeletion of serum proteins from plasma reveals polypeptides that are relatively specific to plasma.

Ampholyte Mixtures↗
PubMed1983

Urinary excretion of proteins in chromeplaters, exchromeplaters and referents.

Urinary excretion of proteins in chromeplaters, exchromeplaters and referents. Scand j work environ health 9 (1983) 505-510. beta 2-microglobulin was measured in the urine of 24 presently exposed chromeplaters, 27 previously exposed chromeplaters, and 37 referents. The concentration of beta 2-microglobulin and the number of "elevated" values (greater than 0.30 mg/l) was higher in the presently exposed group than in the referents. Within the presently exposed group there was a dose-effect relation between the concentration of hexavalent chromium in air and the number of elevated values of urinary beta 2-microglobulin. However, no difference between the previously exposed chromeplaters and the referents could be demonstrated regarding urinary beta 2-microglobulin. There were no indications that the exposure could raise the excretion of albumin in urine. The results seem to indicate an acute effect on the kidney tubules, which is reversible even in workers who have had a relatively high exposure to chromic acid.

Adolescent↗
PubMed1983

Monitoring exposure to chromic acid in chromeplating by measuring chromium in urine.

With personal air samplers, exposure to hexavalent chromium was measured in a group of eight chromeplaters during a period of 5 d; urine samples were collected at all times of urination for 7 d. The concentration of chromium in the urine increased from Monday morning to Tuesday afternoon and then remained constant within the group as a whole throughout the rest of the work week. In a large group of 90 chromeplaters exposure was measured for 1 d, and urine samples were collected before and after the workshift on Monday and Thursday of the same week. There was a correlation between the exposure and the concentration of chromium in postshift urine samples on Thursday (correlation coefficient 0.71). Concentrations of chromium in urine of less than or equal to 100 nmol/l indicate time-weighted average values of exposure of about or below 2 micrograms/m3. Below this exposure no severe damage to the nasal septum and no influence on lung function have been found. After the initial measuring of the airborne hexavalent chromium and the concentrations of chromium in the urine of exposed workers, urine analyses are recommended for follow-up controls.

Adolescent↗
PubMed1982

Characterization of allergen extracts by two-dimensional electrophoretic techniques: Micropolyspora faeni antigens.

Thermophilic actinomycetes and saprobic fungi are important in the etiology of allergic occupational diseases such as "farmer's lung" disease. Each such organism produces several protein antigens. Inhaled, these antigens stimulate production of antibodies. Detection of precipitating antibodies has been useful in the diagnosis of diseases so induced. Characterization of allergen extracts from microorganisms associated with these diseases is important, to improve the sensitivity and precision of the precipitin analysis. For this purpose we submitted crude allergen extracts to electrophoresis and isoelectric focusing in agarose gels. Staining the gels revealed many protein components in each extract, especially after isoelectric focusing. After separation in one dimension, a lane of gel was cut out and the proteins were electrophoresed at right angles into another gel, which contained antibodies. Several arcs of immunoprecipitates, indicating different antigens, were seen. This technique ("crossed immunoelectrofocusing") has earlier been used with polyacrylamide in the first dimension, but it is improved by using instead agarose of a special quality. Further to improve the quantification, we isolated pieces of gel containing the proteins of interest and used them as samples in zone immunoelectrophoresis assay. This method is straightforward, easy to evaluate, and about 100-fold as sensitive as radial immunodiffusion. The amount of protein in each sample is usually proportional to the distance from the upper gel surface to the front of each immunoprecipitate. The increased sensitivity allows study of many hitherto unexamined antigens.

Allergens↗
PubMed1981

Quantification of albumin in urine by a new method: zone immuno-electrophoresis assay (ZIA).

Albumin in urine was determined by a new procedure called zone immunoelectrophoresis assay. A special apparatus was used with 20 vertical glass tubes (diameter 2 mm) which were filled up to 2 cm below their upper orifices with agarose gel containing antibodies against albumin. The samples were pipetted on top of each gel. Albumin was transported by electrophoresis into the agarose gels, in which zones of immunoprecipitates were formed. The amount of albumin in a sample was directly proportional to the distance from the gel surface to the front of the zone. The coefficient of variation was 8.8% within-day and 9.6% between days. The recovery of albumin added to urines was about 101%. The normal range for 40 adult persons was 2--23 mg/l with a mean and a median of 9.9 and 9.5 mg/l, respectively. The detection limit was well below the lowest value. The method was simple to use and the antiserum needed was only 0.5 microliter per test.

Adult↗
PubMed1980

Quantification of antibodies by reversed zone immunoelectrophoresis.

Antibodies against albumin migrate on electrophoresis into agarose gel containing albumin, producing zones of immunoprecipitate (ZIP) in the gel. The amount of antibody in the sample applied is directly proportional to the distance from the point of application (i.e., the gel surface) to the front of the ZIP. This method possesses advantages for antibody measurement over procedures such as radial immunodiffusion and rocket immunoelectrophoresis.

Antibodies↗
PubMed1980

Abnormal distribution of lead in amyotrophic lateral sclerosis--reestimation of lead in the cerebrospinal fluid.

The lead concentration in CSF was determined by flameless atomic absorption spectrophotometry in 16 ALS patients and 22 control cases. The mean values were 0.69 +/- 0.55 (ALS) and 0.41 +/- 0.37 (controls), P < 0.01. This confirms our earlier findings of raised CSF lead levels in ALS but the present values are lower than previously reported for both ALS patients and controls.

Adult↗
PubMed1980

Quantification of proteins with a new sensitive method--zone immunoelectrophoresis assay.

Quantitative determination of proteins has been made by electrophoresis thereof in tubular canals filled with agarose gel containing antibodies. The procedure is simple and practicable. Sample volumes of a few microliter up to some hundred microliter may be added for each test. The amount of protein in a sample was found to be linearly related to the distance from the point of application (i.e. gel surface) to the front of the immunoprecipitation zone. The zone immunoelectrophoresis method shows over rocket immunoelectrophoresis the following advantages: less consumption of antibodies; much lower detection limit (0.05 microgram of protein per ml); larger concentration range with a linear calibration curve. A high correlation (0.98) between the first- and last-mentioned method was obtained for alpha 1-antitrypsin. Precision data are given for albumin and alpha-fetoprotein and typically a relative standard deviation of a few percent was obtained.

Blood Protein Electrophoresis↗
PubMed1979

Direct determination of chromium in urine by electrothermal atomic absorption spectrometry.

A simple, direct method for the determination of chromium levels in urine is described, electrothermal atomic absorption spectrometry having been used after the urine samples had been acidified. The optimal conditions at the ashing and atomization stages was determined. The detection limit of this method is 5 nmol/1, and the coefficient of variation (within day) is about 3% in the concentration range 20--400 nmol/1. Use of a low temperature asher with electrically excited oxygen before analysis gave results similar to those of the direct procedure. Good correlation was obtained from two other laboratories using different instruments and pretreatments.

Chromium↗
PubMed1978

New procedure for concentration and analytical isoelectric focusing of proteins.

Proteins in aqueous salt solutions (up to 4 mil) were adsorbed by hydrophobic interaction on phenyl-Sepharose gel (0.1 ml) in small columns. After washing out excess salt, gels were applied on the surface of flat bed polyacrylamide gels for isoelectric focusing, which resulted in efficient desorption and transport of protein out of the phenyl-Sepharose gel. There was no difficulty in obtaining a fifty-fold concentration. The following parameters at adsorption of protein were studied: (i) salt concentration in the protein solution; (ii) phenyl-Sepharose gel adsorptive capacity for protein; (iii) suitable volume of washing solution for the phenyl-Sepharose gel. Theoretical aspects on factors promoting adsorption and desorption of proteins on phenyl-Sepharose gel are discussed. Also discussed are earlier used procedures for concentration and/or dialysis. When dilute protein solutions are to be examined for analytical purposes, the proposed procedures seems to be a valuable aid, which does not require expensive equipment, and is quick and simple to perform.

Chromatography, Gel↗
PubMed1978

Blood lead determination by flameless atomic absorption spectroscopy.

A simple procedure for flameless atomic absorption analysis of lead in blood is described. It is based on the use of a temperature-controlled heating unit, which, with a photodiode, measures and, by electronic feedback, controls the temperature of the carbon rod. Examination of the influence of various heating has been made. Blood samples with heparin were diluted with Triton X-100, HNO3 added, and 2 microliter of the mixture analysed. Automatic background correction was used. Signals were evaluated by an electronic facility which gives integrated as well as peak height values. The method appears to be accurate and reproducible. The C.V. was, on average, 4%.

Humans↗
PubMed1978

Lead concentration in skeletal muscle in amyotrophic lateral sclerosis patients and control subjects.

The concentration of lead in the vastus lateralis muscle was determined in patients with amyotrophic lateral sclerosis and control subjects by flameless atomic absorption spectrophotometry. No statistically significant differences were found between these groups, and in both the figures were of the same magnitude as those earlier reported for normal individuals. Increased plasma lead concentrations do not seem to cause a significant deposition of lead in skeletal muscle. Therefore, plasma rather than skeletal muscle is the more likely source if pathological amounts of lead enter the motoneurones via the retrograde axoplasmic flow in amyotrophic lateral sclerosis.

Adult↗
PubMed1978

Increased plasma levels of lead in patients with amyotrophic lateral sclerosis compared with control subjects as determined by flameless atomic absorption spectrophotometry.

The levels of lead in plasma were determined in 16 cases of amyotrophic lateral sclerosis (ALS) and 18 control subjects, using flameless atomic absorption spectrophotometry. The mean values were 0.52+/-0.22 microgram/100ml (ALS) and 0.37+/-0.13 microgram/100ml (controls), the difference is statistically significant (5% level). The values in both groups are lower than reported earlier for normal subjects. The findings are discussed against the background of the possible pathogenetic significance of retrograde axoplasmic flow in ALS.

Adolescent↗