Inclusion body myositis in Alzheimer's disease

BACKGROUND

The prevalence of Alzheimer's disease is increasing. Could findings of similar deposits in brain and muscle tissue explain this increase? The purpose of this report is to illustrate that Alzheimer's disease and inclusion body myositis may share a common aetiology.

RESULTS

We present a case where Alzheimer's disease and inclusion body myositis coexist in the same patient. Amyloid-beta deposition and the presence of phosphorylated tau protein have been noted in brain tissue and in muscle biopsy from patients with these disorders.

METHODS

Electrophysiological methods are needed for proper diagnosis of this brain and muscle disorder. Recent data on deposit structures in both conditions may indicate an environmental aetiology for Alzheimer's disease and inclusion body myositis.

CONCLUSION

By combining electrophysiological methods with muscle biopsy in cases of Alzheimer's disease, the possible aetiological connection between simultaneous affection of both muscle and brain in this condition can be established.

Airborne birch and grass pollen allergens in street-level shops

Polluted urban outdoor air may be enriched with large amounts of submicronic respirable pollen allergen particles that penetrate into street-level shops. The objectives of the study were to map concentrations of birch and grass pollen allergens in indoor air of street-level shops and to explore the effect of electrostatic air cleaning under authentic working conditions, indoor air samples were collected in May and July 1999 in two shops. Allergens were quantified by a direct on sampling filter in solution (DOSIS) luminescence immunoassay. The average concentration of airborne indoor birch pollen allergen in the shop with air cleaning was estimated to be 20 +/- 9 SQ/m3 (mean +/- SD) compared to 31 +/- 17 SQ/m3 (mean +/- SD) of that without. The air cleaner reduced the indoor air birch pollen allergen concentration by on average 26 to 48% (P < 0.05). Corresponding figures for airborne indoor grass pollen allergen concentrations were 14 +/- 7 SQ/m3 and 17 +/- 8 SQ/m3, indicating a statistically non-significant (t-test) average 18% reduction of allergen by air cleaning. Excluding two observations with poor fit to the statistical model a significant (P < 0.05) average 27% reduction was obtained. Substantial amounts of airborne birch and grass pollen allergens may occur in street-level shops during flowering seasons.

Albumin, transferrin and alpha2-macroglobulin in bronchoalveolar lavage fluid following exposure to organic dust in healthy subjects

OBJECTIVES

The purpose of the present study was to investigate leakage of plasma proteins in connection with the inflammatory airway reaction following exposure to dust in a pig house. Inhalation of swine-house dust causes intense inflammation with influx of inflammatory cells, predominantly neutrophils, into the airways. The aim of the study was to compare the concentration of three different proteins in bronchoalveolar lavage (BAL) fluid as markers for the inflammation.

METHODS

In twenty healthy, non-allergic, non-smokers, not previously exposed to farm dust, BAL was performed approximately 2 weeks before and 24 h after 3 h of exposure to swine dust in a swine-confinement building. Differential cell count and protein concentration were assessed in BAL fluid. Albumin (66.5 kDa) and alpha2-macroglobulin (720 kDa) were quantified by the use of enzyme-linked immunosorbent assay (ELISA) techniques, and transferrin (80 kDa) by zone immunoelectrophoresis assay. The coefficient of variation for repeated protein measurements was <9%.

RESULTS

alpha2-Macroglobulin concentration increased six-fold, from 68.0 (36.1-99.9) microg/l, mean (95% CI) before exposure to 411.2 (254.0-568.4) microg/l after exposure (P < 0.001). Transferrin and albumin increased from 19.7 (16.2-23.1) mg/l and 1.8 (1.4-2.2) mg/l, 2.6 and 1.9 times, respectively (P < 0.001). There was significant correlation between the exposure-induced increased protein levels in BAL fluid, although alpha2-macroglobulin was a better discriminator of pre- and post-exposure concentrations than were albumin and transferrin. There was a significant correlation between the exposure-induced BAL-fluid neutrophilia and the increase in alpha2-macroglobulin and transferrin, but not for albumin. This correlation was found only when pre- and post- differences, but not ratios, of plasma proteins were compared.

CONCLUSIONS

The levels of plasma proteins increased in BAL fluid following exposure to swine-house dust. alpha2-Macroglobulin was a better marker of this plasma leakage than were albumin and transferrin.

Nickel-induced proteins in human HaCaT keratinocytes: annexin II and phosphoglycerate kinase

It has been established in previous in vitro experiments with human HaCaT keratinocytes that nickel becomes cytotoxic at concentrations higher than 100 microM and that it is accumulated mainly in the cytosolic fraction (Ermolli et al., 2000). The aim of this work was to search possible biomarkers of metal insult, i.e. nickel-binding proteins or proteins differentially expressed in the cytosolic fraction of nickel-exposed cells (up to 1 mM nickel) as compared to controls. Cytosolic proteins were studied by isoelectric focusing (IEF) and two-dimensional gel electrophoresis (2-DE). Separation by IEF revealed nickel-induced changes in the abundance of cytosolic proteins as visualised with nickel-nitrilo-triacetic-alkaline phosphatase (Ni-NTA-AP) in blots. The cytosolic fraction of cells incubated with nickel, at concentrations over 100 microM, showed nickel binding components which were absent or present in significantly lower amounts in control cells. These proteins had isoelectric points (pIs) 6.9, 7.7 and 8.5. After 2-DE silver- and protein staining significantly increased abundance of four proteins was observed. Their pI values corresponded to those of the nickel binding ones seen after IEF. A protein with pI 6.9 had a molecular weight estimated to 38 kDa, two proteins with pI around 7.7 showed molecular weights of 57 and 22 kDa, respectively and another protein with pI of 8.5 had a molecular weight of 33 kDa. The increased abundance of these components, both in IEF experiments and in 2-DE, correlated with the nickel concentration in the culture media. N-terminal amino acid sequencing and database search allowed identification of one a protein as phosphoglycerate kinase and another one as annexin II. The involvement of these proteins in cellular functions and their possible implications in the mechanism of nickel toxicity in keratinocytes are discussed. Some of these proteins may be biomarker candidates for effects of nickel exposure in human keratinocytes.

Miniaturized direct on air sampling filter quantification of pollen allergens

A recently in this journal reported luminescence immunoassay for the direct quantification of birch and grass pollen allergens on air sampling filters. DOSIS, has been miniaturized. By means of a commercially available chlorinated analogue of the previously used 1,2 dioxetane phosphate derivative as enzyme substrate, the air sampling filter diameter could be reduced from 25 mm to 13 mm. The procedure leads to a more than twenty times reduction of the previously reported limit of quantification for the grass pollen allergen.

Mapping of IgE binding regions in the major rat urinary protein, alpha 2u-globulin, using overlapping peptides

Exposure to laboratory animals poses a hazard for development of occupational allergy. Identification of antigenic determinants of allergenic proteins may be valuable for immunotherapeutic purposes. Overlapping peptides of the major allergen in rat urine, Rat n 1.02, corresponding to the protein alpha2u-globulin were synthesised on solid support and screened simultaneously to locate IgE binding linear epitopes using a simple modified ELISA procedure. Thirty-nine peptides were synthesised, each 8 amino acids long with 4 amino acids overlaps. Sera from fifteen rat-sensitized subjects were analyzed and as controls sera from 7 non-rat-sensitized individuals were used. In general low binding and a great individual variation between sera from rat allergic individuals were seen. Some peptides were more frequently recognized by IgE antibodies in sera from rat allergics. These peptides were mainly clustered towards the N-terminal and C-terminal parts of the protein. Taken together our data suggest the existence of linear IgE binding epitopes in the rat urine allergen, Rat n 1.02. However, the role of these sequences in the allergic reaction needs further investigation.

Luminescence immunoassay of pollen allergens on air sampling polytetrafluoroethylene filters

A new method for quantification of airborne birch and grass pollen allergens collected on porous polytetrafluoroethylene filters has been developed. In this method, the allergens firmly adsorbed to the sampling filter of 25 mm in diameter are reacted with specific antibodies conjugated to alkaline phosphatase, generating a matrix-bound allergen-antibody-phosphatase complex. The filter is then floated on a chemiluminescent enzyme substrate solution. The light intensity of the product is linearly related to the amount of allergen over a large mass range, 0-1000 SQ (1 SQ is about 250 pg of protein). This direct on sampling filter in solution (DOSIS) technique demonstrated intra-assay precisions between 6-16% and 11-15% for the levels of 1-100 SQ units of grass allergen Phl p 5 and 4-400 SQ units of birch allergen Bet v 1, respectively. The limits of quantification for the corresponding allergens were estimated to 0.5 and 2 SQ units. Application of DOSIS to analysis of the grass pollen allergen concentrations of outdoor air for 12 days in July 1998 revealed a correlation coefficient of 0.69 between pollen grain and allergen concentrations for the dry weather period. After rainy days large amounts of grass allergens were present even in the absence of pollen grains.

Quantification of birch and grass pollen allergens in indoor air

Birch and grass pollen grains as well as pollen-derived small particles appear as potent allergens in the outdoor air during spring and summer. The occurrence of pollen allergens in indoor air, however, has not been studied in depth due to lack of suitable sampling and analytical methods. Herein, a recently reported "direct on sampling filter estimation" (DOSAFE) technique (Acevedo et al., 1998) has been validated for quantification of pollen allergens in indoor air using two school rooms and two office rooms as experimental models. Using DOSAFE and polyclonal antibodies against water extracts of pollen from Betula pendula and Phleum pratense L, we found that indoor air of school and office rooms carried substantial amounts of pollen allergens, expressed as SQ units, predominantly occurring as particles with smaller diameters than the pollen grains. In one school room the indoor air birch pollen allergen concentrations increased from 242 to 403 SQ units/m3 over the sampling period although the corresponding outdoor air concentrations decreased from 350 to 90 SQ units/m3. Electrostatic air cleaning in one office room reduced its grass pollen allergen concentrations by more than 95% to 0.02-0.34 SQ units/m3 as compared to the control room.

In memory of Harry Rilbe: an outstanding scientist who made many valuable contributions to the development of electrophoretic methods

In July 1997 Professor Harry Rilbe passed away at the age of 84. Harry Rilbe was an outstanding personality skilled in chemistry, optics and mathematics, and he will be remembered for his important contributions to the development of separation methods, notably moving boundary electrophoresis and isoelectric focusing. The latter method is used for analytical and preparative purposes in thousands of laboratories worldwide. Isoelectric focusing is indispensable for characterization of proteins from humans, animals, plants and microorganisms. Isoelectric focusing is thus useful for the understanding of the function of genes and, accordingly, for progress in the life sciences. A biographical retrospect, "A scientific life with chemistry, optics and mathematics", was published by Harry Rilbe in Electrophoresis 1984, 5, 1-17.

Rat urinary proteins binding human IgE detected by chemiluminescence

Work with laboratory animals involves the increased risk of developing an allergy. Certain proteins in male rat urine have been shown to be major allergens, i.e., Rat n 1.01 and Rat n 1.02. Rat urinary proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were electro-blotted to polyvinylidene difluoride (PVDF) membranes. Immunoblot analysis of human IgE binding components in rat urine utilizing chemiluminescence and a newly developed luminometer is described. Luminometer scanning curves of IgE reactivity to the separated rat urinary proteins are demonstrated. Rat allergic individuals showed different immune responses to the separated proteins. Rat n 1.02, also known as the major protein alpha2mu-globulin, was not always the dominant allergen. Another protein in the albumin region, 60-67 kDa, was found to be an important allergen to some rat-sensitive subjects. Reactivity in the skin prick test with purified Rat n 1.01 and Rat n 1.02 fractions were strong. However, in dot blot under nondenaturing conditions, only weak responses were obtained to the purified rat urinary proteins except for the albumin fraction. Chemiluminescence measurements in blotting membranes of patient IgE bound to different dilutions of certain rat urine proteins revealed good quantitative relationships. Three different chemiluminescence substrates were tested. Measurement of IgE bound to individual allergens as well as the abundance and relative importance of various allergens were studied.

Visualization and quantification of birch-pollen allergens directly on air-sampling filters

A new technique is presented to detect and quantify birch (Betula pendula)-pollen allergens directly on air-sampling filters. It is based on the use of specific antibodies, enzymatic reactions, and measurement by chemiluminescence or densitometry. The major pollen antigens are the most important birch allergens. The antibodies used recognize birch-pollen antigens which thus correspond to allergens. Calibration was done with a standardized extract of birch pollen for skin prick testing. The correlation coefficient for the logarithms of luminescence and the amount of birch-pollen allergen applied on filters was > 0.98 in the range 0.04-200 SQ units. A similar correlation was found for the logarithms of the integrated densitometry values and the amount of birch-pollen allergen applied on filters. The number of major pollen-antigen particles or grains on filters could be estimated by counting the major stained spots produced by precipitated enzymatic products. The correlation coefficient was 0.90 for the logarithms of the number of counted major antigen spots and the calculated antigen amount obtained by luminometric measurements. Our results demonstrate that birch-pollen allergens can be determined directly on air-sampling, Teflon-based filters by luminometry, optical density, or particle counting.

A zone immunoelectrophoresis assay method for quantification of apolipoprotein D in human cerebrospinal fluid

A zone immunoelectrophoresis assay (ZIA) has been developed for the quantification of apolipoprotein D (apo D) in human unconcentrated cerebrospinal fluid (CSF). The apo D concentrations of samples of the serum, plasma and CSF were directly proportional to the migration distances of the corresponding zones of immunoprecipitates developed during electrophoresis in glass capillaries filled with antibody-containing agarose gel. A linear standard curve, between about 1 and 12 mg of apo D/1 was obtained using a commercial serum preparation. Seronorm, as apo D standard. The coefficients of variation of the ZIA were below 8% (n = 5 x 6) and 10% (n = 8) for within-run and between-run reproducibility, respectively. Quantification experiments with disulfide-reducing agent, mixtures of CSF and urine as well as frozen and stored CSF samples indicated parallelism between the precipitate-forming immunologic reactions of apo D in different sample matrices when performed with ZIA. Application of this method to quantify apo D of CSF and plasma samples from 51 normal healthy men aged 16-72 years yielded means +/- SD of 5.3 +/- 1.5 mg/l and 128.4 +/- 22.7 mg/l, respectively. No correlation was found between the CSF and plasma apo D concentrations.

A critical review on normal concentrations of vanadium in human blood, serum, and urine

An evaluation of published values for 'normal' concentrations of vanadium levels in human blood, serum, and urine have been determined in order to identify the reasons for existing large variations of these values. The published data were scrutinized according to criteria on sampling and analysis developed for the TRACY (EUREKA; ENVIRON1) project which aims at establishing reference values for persons without occupational exposure to metals. Of the sampling factors, living in environmentally polluted areas, contamination-free sampling and sample handling were found to be highly important. Expert experience is needed for the accurate vanadium determination in these fluids using well defined radiochemical neutron activation analysis (RNAA) or NAA with pre-irradiation separation or graphite furnace atomic absorption spectrometry (GF-AAS). RNAA is superior for this purpose. Lack of suitable reference materials is a severe handicap in assessing accuracy of vanadium determinations at low levels. Although no reference values for vanadium are established, it appears that values, around 1 nmol l-1 for blood and serum and around 10 nmol l-1 or slightly lower for urine may be considered tentative normal values.

Purification and identification of allergenic alpha (2u)-globulin species of rat urine

Amino-acid compositional and sequence analyses as well as mass spectrometric determinations of purified rat urine proteins, previously termed prealbumin and alpha(2)-euglobulin, have revealed a high homology between the two forms which have now been identified as alpha(2)-globulin species. The "prealbumin' fraction was found to correspond to alpha(2u)-globulin originating from salivary gland and the 'alpha(2)-euglobulin' fraction was identical with the major urinary protein (MUP) or alpha(2u)-globulin. The results indicate that the two major protein fractions of rat urine constitute different forms of the same parent protein, alpha(2u)-globulin, having no amino-acid sequence resemblance to prealbumin (transthyretin) of rat serum.

Sample collection guidelines for trace elements in blood and urine. IUPAC Commission of Toxicology

This paper presents an organized system for element-specific sample collection and handling of human blood (whole blood, serum or plasma, packed cells or erythrocytes) and urine also indicating a proper definition of the subject and sample. Harmonized procedures for collection, preparation, analysis and quality control are suggested. The aim is to assist scientists worldwide to produce comparable data which will be useful on a regional, national and international scale. The guidelines are directed to the elements aluminium, arsenic, cadmium, chromium, cobalt, copper, lead, lithium, manganese, mercury, nickel, selenium and zinc. These include the most important elements measured for their occupational or clinical significance, and serve as examples of principles that will guide development of methods for other elements in the future.

Protection against cadmium-metallothionein nephrotoxicity in streptozotocin-induced diabetic rats: role of increased metallothionein synthesis induced by streptozotocin

Protection against the development of nephrotoxicity following the administration of cadmium-metallothionein (CdMT) at a dose of 0.4 mg Cd per kg body weights was studied in streptozotocin (STZ)-induced diabetic rats. Six groups of Wistar male rats were used (Groups A and B, Groups A1 and C, and Groups A2 and D were injected intraperitoneally with STZ at doses of 0, 50 and 100 mg/kg, respectively, and then 6 days later, Groups B, C and D were injected subcutaneously with CdMT). Proteinuria, albuminuria and transferrinuria were observed after the administration of CdMT, and a dose-related decrease following the increased STZ dose was seen in Groups B, C and D. The concentrations of metallothionein (MT) and zinc (Zn) in liver and kidney were dose-dependently increased in Groups B, C and D. Induction of increased MT synthesis in liver and kidney as the result of the STZ treatment was observed in this study. In particular, a remarkable increase in liver MT concentration was induced by STZ, and transport to the kidney of MT synthesized in liver may perhaps explain the protection against cadmium nephrotoxicity in STZ-induced diabetic rats.

A new luminometer for sensitive quantification by chemiluminescence of specific proteins in microtitre plates and on blot membranes

Generally applicable technologies are described, which depend on the use of chemiluminescence and a new type of a versatile luminometer, that can measure also weak light in microtitre plates (microplates) and on blotting membranes that is especially useful for dot blot immunoassay. Applications are described using alkaline phosphatase conjugated antibodies against IgG and IgE and the reagent Lumi-Phos 530. This chemiluminescence offers advantages over the use of radioactive isotopes, densitometry and light reflection measurement on membranes and also ELISA, for sensitive quantification of e.g. specific proteins. Special procedures are described for the first time that with the mentioned reagent in agarose gel allows specific and very sensitive quantification of proteins on dot blot membranes. The luminometer, which has temperature control, is very sensitive, precise and allows efficient protocols for various assays. It thus fulfils many of the requirements for good quantification, is time-saving and in addition brings significant improvements due to very low detection limits and large linear concentration ranges that can be measured with excellent regression coefficients (r2 often about 0.999).

Sensitive quantification of proteins by electrophoresis in gels by use of chemiluminescence

For protein quantitation in gels or blotting membranes, chemiluminescence (CL) offers the advantages of a substantial improvement of detection limits. Easy-to-use CL-chemicals and specific probes such as antibodies conjugated to enzymes, e.g. alkaline phosphatase (AP) may be used in combination with a newly developed luminometer. CL was found to have low detection limits and a linear relation between relative light units (RLU) and the concentration of the antibody enzyme complex present over a wide concentration range. Measurements of the immunoglobulin IgE in dot blots and in blots after sodium dodecyl sulfate (SDS) electrophoresis under nonreducing conditions in agarose gels are described.

Estimation of pooled reference values for cadmium in blood using meta-analysis and TRACY criteria

Reference values for blood-cadmium levels (B-Cd) are available for only a limited number of geographical areas and for particular population strata (sex, age, smoking habits). This paper, in agreement with the TRACY guidelines, describes and discusses the criteria used to rank published papers on reference values for cadmium retrieved by Medline and Toxline between 1976 and 1991. The TRACY criteria deal with the grading of published papers in terms of their suitability for calculating provisional reference values. Only four out of 18 papers were considered suitable for the TRACY project. The four articles were finally used via meta-analysis to provide provisional reference values for smokers and non-smokers. The comparison of results obtained using published statistics and individual data is used to discuss the appropriateness of meta-analysis in the case of cadmium. Due to the availability of large enough studies and to the clear differences across countries, the suitability of a compound upper reference limit to B-Cd levels seems limited.

Specific, sensitive and accurate quantification of albumin, retinol binding protein and transferrin in human urine and serum by zone immunoelectrophoresis assay (ZIA)

For zone immunoelectrophoresis assay (ZIA) glass tubes, ID 2 mm and 90 mm high, are filled to 2/3 with buffer containing agarose and antibodies against the protein to be quantified, each sample being pipetted on top of separate agarose gel rods. On electrophoresis at 35-150 V for several hours, the sample proteins enter the gel with resultant immunoprecipitates, visualized by staining. The extension of each immunoprecipitation zone from the upper gel surface (measured with a ruler) is directly proportional to the amount of protein in each sample and can easily be quantitated by comparison with a linear calibration curve. ZIA can be used for quantification of several proteins in blood serum and plasma as well as in urine, as is illustrated for albumin, retinol-binding protein (RBP) and transferrin. The recovery of the pure proteins added to urine is often close to 100%. ZIA has many advantages: (i) simple apparatus and procedure (no gel punching nor cooling), (ii) minimal antiserum consumption (1 mL may allow > 1000 assays), (iii) electrophoresis can be performed within a few hours or overnight, (iv) low coefficient of variation (often < 4%), (v) linear calibration curves, (vi) low detection limit (< 20 ng/mL), (vii) wide concentration ranges, (viii) no kits nor unique antisera preparation are required, and (ix) good agreement with the results from other methods.

Liver function tests and urinary albumin in house painters with previous heavy exposure to organic solvents

The serum activities or concentrations of aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), alkaline phosphatase (ALP), albumin, gamma-glutamyl transpeptidase (GGT), bilirubin (BIL), cholic acid (CHOL), chenodeoxycholic acid (CHENO), and transferrin with isoelectric point 5.7, and the urinary excretion of albumin were determined among male current or former house painters (n = 135) and house carpenters (n = 71) who had worked in their trades for at least 10 years before 1970. Workers who showed a value above the 90th percentile among the carpenters in at least one of the tests ASAT, ALAT, GGT, BIL, CHOL, or CHENO were regarded as showing "possible signs of liver dysfunction". Each participant's lifetime solvent exposure was evaluated by interview. The painters were divided into categories with low, intermediate, and heavy cumulative exposure during life (LTSE) or during the most exposed year (MEYSE). All participants stated none or slight recent exposure. The prevalence of possible signs of liver dysfunction increased with solvent exposure category according to LTSE as well as MEYSE with a numerically higher risk estimate in the heavy exposure category for MEYSE than for LTSE. ALP activity increased with exposure category according to both exposure estimates. This increase seemed to be due to an interaction between exposure to solvents and current or previous long term intake of medicines potentially toxic to the liver. None of these results was affected by whether or not the subjects had been exposed to solvents during the year before the investigation. The exposure to solvents was not significantly related to any other outcome variable. It is concluded that long term heavy exposure to solvents may elicit changes in conventional liver function tests indicative of a mild chronic effect on the liver. The findings also suggest that heavy solvent exposure during short time periods is a more likely cause of the findings than lifetime cumulative solvent exposure and that an interaction between solvent exposure and medicines potentially harmful to the liver may be important in the causation of the effects.

DMSA administration to patients with alleged mercury poisoning from dental amalgams: a placebo-controlled study

The present investigation was performed to determine the effect of 14-day oral administration of meso-2.3-dimercaptosuccinic acid (DMSA) on the urinary mercury excretion and the potential reduction of blood and plasma mercury concentrations, and also to relate these effects to possible decrease of symptoms, allegedly associated with amalgam fillings. Twenty subjects, relating their symptoms to mercury from amalgam fillings, received 20 mg/kg DMSA or placebo for 14 days. Their symptoms and mood states were recorded during the study and at a check-up 3 months later. Interpretation was based on intra-individual differences. DMSA-treatment resulted in an average increase in urinary mercury excretion by 65% and a decrease in blood mercury levels of 0.04 microgram/L/day. At the check-up after 3 months, urinary mercury excretion had returned to the pre-treatment level. No treatment effect of DMSA was apparent on subjective symptoms and mood state. One statistically significant treatment effect was noted-a decrease in fatigue-inertia in the DMSA-group-but there was no demonstrable correlation with increased urinary excretion or decreased blood concentration of mercury. Three subjects showed hypersensitive reactions, probably DMSA-specific, at the end of the treatment period. This placebo-controlled study provides no scientific support for diagnostic or therapeutic administration of DMSA for symptoms allegedly associated with chronic mercury exposition from dental amalgam fillings.

A short history of electrophoretic methods

High resolution separation of proteins, based on charge differences, is possible with disc electrophoresis, displacement electrophoresis (isotachophoresis) and notably isoelectric focusing (IEF). Size separation is obtained in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The combination of gel IEF, followed by SDS-PAGE in a second-dimensional slab gel, i.e. two-dimensional gel electrophoresis, affords the highest resolution with up to several thousand spots per gel. Staining of proteins gives high resolution patterns which can be scanned and stored in comprehensive databases. Over the last 10 years the electrophoretic separation in gels and subsequent visualization of nucleic acids (DNA, RNA) and even genes as well as nucleotides have been much improved, making possible efficient mapping of the genes in humans and all other organisms. This has led to the biggest concerted endeavor in the history of science, i.e. the mapping of the human genome, which will be of importance as long as mankind exists. In the last years electrophoresis in capillaries has attracted much interest because for numerous substances, such as proteins nucleic acids, pharmaceuticals, metabolites, and peptides, it offers high resolution on the analytical scale with over 1 million theoretical plates. Electrophoretic methods have unprecedented impact on life sciences, providing a basis for unique advances in biochemistry, molecular biology, genetics, gene technology and medicine.

Electrophoretic analysis of stimulated cat parotid saliva

The proteins of parasympathetically stimulated cat parotid saliva were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE). SDS-PAGE revealed up to 30 polypeptide bands in microliter volumes of unconcentrated saliva. The patterns were highly reproducible and characterized by prominent bands of M(r) 57,000, M(r) 30,000 and M(r) 15,000. The major protein (M(r) 30,000) appeared as a dimer (M(r) 60,000) when electrophoresed under non-reducing conditions but dissociated into its monomeric form when the SDS concentration of the denatured samples was increased from 1 to 5%. This indicates a noncovalent association. The protein patterns of saliva from different cats differed slightly but sequential samples from the same cat (collected during 90 min of stimulation) showed little change in protein pattern apart from a fall in total protein content. Following 2-DE, the major protein (M(r) 30,000) appeared as a complex array of at least eight spots in two tiers (pI 5.2-6.2; M(r) 28,000 and 32,000). The characteristics of this protein are discussed with reference to allergy to cats.

Apolipoprotein D and alpha 1-microglobulin in human urine: effect of cadmium exposure

Apolipoprotein D is a previously unrecognized urinary protein of unknown function which we have tested as a potential marker for kidney malfunction. This protein and alpha 1-microglobulin have been quantified by zone immunoelectrophoresis assay in urine samples from a group of eight men occupationally exposed to cadmium-containing welding fumes for many years. All these workers had highly elevated concentrations of urinary cadmium and indications of tubular proteinuria, as compared to a group of 50 apparently healthy normal men analyzed in parallel. The cadmium-exposed workers demonstrated three- and 15-fold average increases in apolipoprotein D and alpha 1-microglobulin, respectively, over normal values in urine, estimated both as excretion rates and as milligrams of protein per mmol of creatinine. All these increments were highly significantly different (P < 0.001) from the corresponding values of the reference group. Essentially the same results were obtained for each of the proteins from two independent consecutive samplings of the workers' urine. There were good linear (R = 0.70, 0.80) and logarithmic (R = 0.84, 0.81) correlations between the urinary concentrations of alpha 1-microglobulin and apolipoprotein D for both the reference and the study group. Although not as sensitive an indicator for tubular proteinuria as alpha 1-microglobulin, apolipoprotein D, being a storage-stable urinary protein, seems a valuable complement for the diagnosis of tubular malfunction.

Renal and immunological effects of occupational exposure to inorganic mercury

Seven parameters of renal dysfunction (urinary excretion of albumin, orosomucoid, beta 2-microglobulin, N-acetyl-beta-glucosaminidase (NAG), and copper; serum creatinine concentration, and relative clearance of beta 2-microglobulin) were examined in a group of chloralkali workers exposed to mercury vapour (n = 89) and in an unexposed control group (n = 75). Serum concentrations of immunoglobulins (IgA, IgG, IgM) and auto-antibodies towards glomeruli and other tissues were also determined. The parameters examined were compared between the two groups and related to different exposure parameters. In the chloralkali group median blood mercury concentration (B-Hg) was 55 nmol/l, serum mercury (S-Hg) 45 nmol/l, and urine mercury concentration (U-Hg) 14.3 nmol/mmol creatinine (25.4 micrograms/g creatinine). Corresponding concentrations for the control group were 15 nmol/l, 4 nmol/l, and 1.1 nmol/mmol creatinine (1.9 micrograms/g creatinine) respectively. None of the parameters of renal dysfunction differed significantly between the two groups, but there was a tendency to increased excretion of NAG in the exposed group compared with the controls. Also, a statistically significant relation existed between U-Hg and U-NAG (p less than 0.001). Serum immunoglobulin concentrations did not differ between the groups, and serum titres of autoantibodies (including antiglomerular basement membrane and antilaminin antibodies) were low in both groups. Thus the results gave no evidence of glomerular damage or of a tubular reabsorption defect at the current relatively low exposures. The findings still indicate slight, dose related tubular cell damage in the mercury exposed group. There were no signs of a mercury induced effect on the immune system.

Kidney effects in long term exposed lead smelter workers

Occupational exposure to lead may cause kidney damage. This study was carried out on a cohort of 70 active and 30 retired long term exposed lead smelter workers. Their kidney function was compared with 31 active and 10 retired truck assembly workers who had no occupational exposure to lead. The lead workers had been regularly followed up with measurements of lead concentration in blood since 1950. Previous exposure to lead was calculated as a time integrated blood lead index for each worker. Blood and urine samples were obtained from all subjects. The concentration of lead in blood (B-Pb) and urine (U-Pb) was analysed. The urinary concentrations of several sensitive indicators of early tubular (U-beta 2-microglobulin (U-beta 2-m); U-N-acetyl-beta-glucosaminidase (U-NAG)) and glomerular kidney damage (U-albumin) were determined. The B-Pb and U-Pb values were significantly higher among active and retired lead workers compared with their corresponding control groups. The highest concentrations were found among the active lead workers. The concentrations of the parameters of kidney function investigated were of the same magnitude for exposed workers and controls. No clinical signs of renal impairment were found among the workers. No correlations of clinical importance existed between concentrations of U-albumin, U-beta 2-m, and U-NAG activity on the one hand and the concentrations of B-Pb, cumulative blood lead index, U-Pb, and lead concentrations in the calcaneus and tibia on the other, among lead workers and controls. Despite many years of moderate to heavy exposure to lead, particularly for the retired lead workers, no signs of adverse effects on the kidney such as early tubular or glomerular malfunction were found. Reversible changes in kidney function during the 1950s and 1960s could not be excluded, however, due to a greater exposure to lead during that time.

Quantification of apolipoprotein D in human urine by zone immunoelectrophoresis assay: a methodological and clinical study

A zone immunoelectrophoresis assay (ZIA) has been developed for the quantification of apolipoprotein D (apo D) in unconcentrated native human urine. A standard curve, linear between 1 and 8 mg apo D/l was obtained with ZIA. The relative coefficients of variation for this method were 5-9% (n = 15 x 6) with a mean +/- SD of 7 +/- 1.4% and below 11% (n = 6 x 15) for within-run and between-run reproducibility, respectively. Equal amounts of apo D in unconcentrated and diluted urines, in serum and of the purified protein produced the same zone migration distances indicating parallelism between the immunologic reactions of apo D in different sample matrixes. Storage experiments with normal urines demonstrated good stability of apo D in both acidic and alkalinized urine over at least 2 days at +5 degrees C and during several days at -20 degrees C to -40 degrees C. Using ZIA, urine samples from 50 normal healthy men aged 23-65 years were analyzed for apo D. Mean and SD were: 2.8 +/- 2.1 mg/l, 2.6 +/- 1.8 micrograms/min and 0.24 +/- 0.13 mg/mmol for concentration, rate of excretion and mass/creatinine concentration, respectively.

Automatic method for quantitation of mercury in blood, plasma and urine

Here we report our experience of quantification of mercury in blood, plasma and urine by using modifications of a procedure for cold vapour atomic absorption. We have tried: (1) modifications of the instrumentation including the tower, the cell and apparatus for measurement; (2) to increase the volume of sample, avoiding problems caused by foaming and background to arrive at a reliable method with low detection limit. Blood and plasma samples were digested overnight in a mixture of nitric acid and perchloric acid (1:5). Recovery of known additions of mercury was close to 100%. Coefficients of variation (CV) within runs and between runs was for B-Hg 4.7 and 9.5, respectively at 20 nmol/l, and for U-Hg 1.8 and 5.2, respectively at 57 nmol/l. The same detection limit of 5 nmol/l was obtained with blood, plasma and urine. This is in the lower range of non-occupationally exposed normal subjects. The results, including those obtained in sample exchange with other laboratories and with reference materials, indicate that the accuracy of this method for quantification of mercury is good.

Biological monitoring of environmental and occupational exposure to mercury

Biological monitoring was used to assess mercury exposure from occupational and environmental sources in a group of chloralkali workers (n = 89) and in a control group (n = 75). In the control group, the median value for blood mercury (B-Hg) was 15 nmol/l, that for serum mercury (S-Hg) was 4 nmol/l and that for urinary mercury (U-Hg) was 1.1 nmol/mmol creatinine. Corresponding levels in the chloralkali group were 55 nmol/l, 45 nmol/l and 14.3 nmol/mmol creatinine, respectively. In the control group, there were statistically significant relationships between fish consumption and both B-Hg and S-Hg values (P less than 0.001), whereas U-Hg correlated best with the individual amalgam burden (P less than 0.01). In the chloralkali group, the mercury levels in blood and urine were significantly related to the type of work (P less than 0.001) but not to the length of employment, to fish consumption or to the quantity of dental amalgam fillings. In both groups there were poor correlations between smoking or alcohol intake and the mercury levels in blood and urine. The results strongly suggest that fish is an important source of methylmercury exposure and that amalgam fillings are probably the most important source of inorganic mercury exposure among occupationally unexposed individuals. In the chloralkali group, mercury exposure from fish and amalgam was overshadowed by occupational exposure to inorganic mercury.

Haematological changes in house painters using epoxy paints

Haematological parameters, iso-transferrin ratio in plasma and serotonin uptake in platelets were studied in 10 men (age range 21-54 years) with occupational long-term, low level exposure to vapours from epoxy paints. The control group consisted of 10 healthy men (age range 20-48 years) not occupationally exposed to chemicals or organic solvents. The mean cellular volume of erythrocytes was significantly higher for the house painters than the controls (p less than 0.05). The plasma concentration of iso-transferrin with isoelectric point 5.7 (Tf5.7) and the ratio between Tf5.7 and total transferrin (Tftot) were significantly higher in the exposed group (p less than 0.05). The uptake of serotonin in platelets (Vmax) from the exposed workers was significantly lower than the values for the controls (p less than 0.01). The results indicate an association between the observed biological effects and the chemical exposure, and we speculate that this is caused by changes in structure and function of the cell membranes.

On the possibility of differential diagnosis at elevated erythrocyte sedimentation rate by analysis of the concentrations of blood plasma proteins--a model study

An elevated erythrocyte sedimentation rate is generally regarded as an unspecific and mostly pathological indicator of inflammation or tumour. However, we have determined the concentrations of plasma/serum proteins that influence the erythrocyte sedimentation rate in numerous samples from several groups of patients with different diseases, including 2 forms of cancer. Equations have been developed by which the 1 h value of erythrocyte sedimentation rate can be expressed as the sum of disease-specific coefficients for each protein multiplied by the measured concentrations of the respective proteins. These equations are shown to be disease-specific with 64-93% probability. Such equations may thus form the basis for differential diagnosis.

Increased isotransferrin ratio and reduced erythrocyte and platelet volumes in blood from thermoplastic industry workers

Ten women (aged 31-61 years) and five men (aged 20-59 years) occupationally exposed to welding fumes of polyacetate containing diethylphthalate in a thermoplastic industry were studied. They had been employed 1-33 years (median: 11 years). Seven women (aged 35-55) and eight men (aged 26-73) acted as unexposed controls. The exposed persons showed increased isotransferrin ratio in blood serum and reduced volumes of erythrocytes and platelets in blood.

High performance concentration and gel filtration of rat urinary protein allergens

Allergies to laboratory animals, notably rats, have become an increasingly recognized occupational problem. Identification and isolation of the individual proteins causing allergic reactions, could form the basis for early recognition of sensitivity, diagnosis, control of degree of pollution of the environment and desensibilization treatments. Frequently, allergens originate from dried rat urine. Because earlier published methods were found unsatisfactory we have developed a new strategy for isolation of rat urinary proteins including a high performance technique for their mild concentration on hydroxyapatite. The concentrated allergens have been fractionated according to molecular size by high performance gel filtration and according to carbohydrate content by wheat germ lectin-Sepharose 6 MB affinity chromatography. The obtained fractions have been examined by denaturing and non-denaturing polyacrylamide gradient gel electrophoresis followed by sensitive staining procedures, and tested with respect to allergenicity by skin tests on allergic patients.

History of electrophoretic methods

Electrophoresis is the migration of electrically charged particles or ions in solutions due to an applied electric field. The ability to separate very similar substances including different proteins for analytical and preparative purposes has increased, especially since 1950, owing to the introduction of zone electrophoresis in paper and later in gels of polyacrylamide or agarose. After 1960, disc and displacement electrophoresis (isotachophoresis) and isoelectric focusing offered much increased resolution. Electrophoretic methods nowadays promote advances in biochemistry and molecular biology and will continue to be very important in science and for numerous applications in genetics, gene technology, sequencing of nucleic acids and proteins, studies of diseases and malfunctions including cancer, and in the identification of species and individuals, e.g., in forensic medicine.

Separation of different forms of transferrin by isoelectric focusing to detect effects on the liver caused by xenobiotics

Several genetic variants and also isoforms of transferrin differing in carbohydrate structure can be separated by polyacrylamide or agarose gel isoelectric focusing. Numerous blood plasma or serum samples can be analyzed in parallel in each gel. Studies of the heterogeneity of transferrin have already revealed many results of importance to different fields of human medicine. Gene typing can give important and useful information for paternity determination and in forensic medicine. The gene type C 2 seems to have increased frequency in certain malfunctions. Futhermore, functional abnormalities of liver cells can be revealed by determination of the concentrations of transferrin isoforms differing mainly in their carbohydrate parts. The isoforms can be quantified with zone immunoelectrophoresis assay. Thus valuable information can be obtained about important modulated regulations of cell and membrane functions, even when these are disturbed by disease and xenobiotics. The information may be useful e.g. in the detection of individuals suffering from toxic effects, to identify toxic agents and exposure conditions. Studies of house painters revealed that exposure to different types of paints had an effect on transferrin. Determination of the concentration of the isotransferrin with pI 5.7 in blood samples from alcoholics can be used as a marker for the detection of liver dysfunction and for the monitoring of therapy treatments. In addition, by analyzing the isotransferrins a rare genetic abnormality can be detected.

The N-acetylneuraminic acid content of five forms of human transferrin

Five isoforms of human serum transferrin were separated by isoelectric focusing and their N-acetylneuraminic acid content was determined. The forms differed in isoelectric point by about 0.1 of a pH unit with the structural differences situated in the carbohydrate parts. Each form had one sialic acid molecule (NANA) less than the next most acidic form. GLC-MS showed that the most abundant form with isoelectric point 5.5 had two two-branched carbohydrate chains, each having the galactoses covered by terminal sialic acid. The form with isoelectric point 5.4 had one three-branched and one two-branched carbohydrate chain, and all branches terminated with a sialic acid residue. The form with isoelectric point 5.6 had a terminal galactose on one of its two two-branched carbohydrate chains. Comparison of the sialic acid content of the five transferrin forms and their carbohydrate structures showed that some of the forms expose terminal galactose without attracting the asialoglycoprotein receptors on hepatocytes.

Urinary excretion of chromium in chromeplaters after discontinued exposure

In a previous study [Lindberg and Vesterberg, 1983a], excretion of chromium in urine (U-Cr) in chromeplaters was proposed for biological monitoring of ongoing exposure. Published reports were found about the decline of U-Cr after discontinued exposure in welders working in chromium-alloyed stainless steel, but not in chromeplaters. In this study, half-times (t1/2) were calculated for ten chromeplaters over a weekend, and for 23 chromeplaters over 31 days vacation. The results suggest that the excretion of chromium can be approximated to a two-compartment model. Estimated from the median values, an initial rapid phase with an assumed t1/2 of 2-3 days is followed by a phase with a t1/2 of approximately a month. Differences between the decline of U-Cr in chromeplaters and welders are discussed.

Concentration differences in isoforms of transferrin in blood from alcoholics during abuse and abstinence

At least five different forms of iron-saturated transferrin (Tf) from blood plasma can be separated by isoelectric focusing. These transferrin forms differ in the carbohydrate parts, especially the amount of sialic acid. The increased relative concentration of the form with isoelectric point 5.7 (Tf5.7) has been shown to be a good indicator for liver effects caused by alcohol abuse. However, in alcoholics during abstinence the newly formed transferrin has a higher sialic acid content than most of the transferrin already present in the blood. This indicates that the elevated concentration of Tf5.7 with a low sialic acid content, found in alcoholics is not due to a defect at sialylation, but most probably caused by an impaired uptake of sialic acid-deficient transferrin by the hepatocytes due to membrane dysfunction.

Biological exposure limits estimated from relations between occupational styrene exposure during a workweek and excretion of mandelic and phenylglyoxylic acids in urine

Styrene exposure of 18 workers in fiberglass reinforced plastic industries was measured for 30-min periods throughout each workday for a week. The styrene uptake was estimated using pulmonary ventilation measurements. All urine voidings were collected separately and the styrene metabolites, mandelic acid (MA) and phenylglyoxylic acid (PGA) were determined. The relationship between both exposure and uptake versus excretion of these metabolites was studied. Styrene metabolite concentrations and excretion rates (with 95% tolerance limits) were calculated to correspond to a constant 8-h exposure at the Swedish exposure limit level (25 ppm) or an uptake of an exposure limit related styrene dose (6.3 mmol). The tightest tolerance limits were obtained for excretion rate of MA + PGA per 24 h. The calculated biological exposure limit was 3.4 (+/- 0.7) mmol MA + PGA/24h for a dose of 6.3 mmol styrene.