Pål Stenberg

Socioeconomic factors, morbidity and drug utilization—an ecological study

The aim of the present study was to elucidate the relations between demographic and socioeconomic factors, morbidity and the utilization of major drug groups in an urban Swedish population. The study was performed as an ecological analysis during November 1991 in the 17 different districts of Malmö, the third largest Swedish city (235,000 inhabitants).

Transglutaminase and the pathogenesis of coeliac disease

In 1997, a German group demonstrated that the antigen of the biomarker EMA (endomysial antibodies) in coeliac disease is a calcium-dependent thiol enzyme, transglutaminase type 2 (TG2). This most important discovery opened up an exciting field of research aimed at a better understanding of the pathogenesis of coeliac disease, a T-cell-driven autoimmune disorder with a prevalence of about 1%. The accidental activation of TG2, possibly caused by a stress-induced local deficiency of zinc in the intestinal wall, might play a key role where the enzyme catalyzes an atypical deamidation of specific glutamine residues of food gliadins. The genetic contribution is HLA DQ2 or DQ8, which can form a complex with the TG2-modified gliadin residues, resulting in an immune response with the formation of antibodies against both gliadin and the enzyme. Indeed, the immunopathogenesis of coeliac disease can now be recognized partly at the molecular level. Progress has already improved the opportunities for laboratory diagnostics and, hopefully, new ways of treating and preventing coeliac disease will become available. These exciting developments might stimulate research within other fields of autoimmune disorders. With its focus on TG2, this review highlights some of the intriguing mechanisms of the pathogenesis of coeliac disease, such as the structure of the neo-antigen, the involvement of calcium and zinc, and the effects of coeliac antibodies on TG2 activity. Moreover, the many pitfalls due to dubious laboratory practice are addressed, as is the potential when a fundamental biological mechanism is understood at the molecular level.

Intra-urban variation of antibiotic utilization in children: influence of socio-economic factors.

AbstractObjective: The aim of this study was to investigate the intra-urban variation of antibiotic utilization in children in Malmö and to evaluate the influence of socio-economic factors on this variation. Methods: In an ecological analysis, the variations in antibiotic utilization in children, expressed as defined daily dose (DDD) or as the number of prescriptions per 1000 inhabitants per day, were compared with variations in socio-economic and demographic factors in the 17 administrative districts of the Swedish city of Malmö (235 000 inhabitants). Results: There were large between-area differences in antibiotic utilization, especially in children aged 0–6 years. Socio-economic factors reflecting a privileged situation correlated positively with antibiotic utilization. Thus, in districts with a high median family income and a high employment rate, the utilization of antibiotics was higher than in other districts. Conversely, in districts with a high proportion of blue-collar workers, people with foreign backgrounds and recipients of social benefit, antibiotic utilization was comparatively low. In contrast, the utilization of penicillin V relative to other antibiotics showed an opposite pattern, including positive correlations with the proportion of social benefit, immigrants and blue-collar workers and a negative correlation with employment rate. Conversely, the utilization of macrolides in relation to other antibiotics in children aged 0–6 years was highest in districts inhabited by those who were socio-economically privileged. Interpretation: The findings suggest that utilization of antibiotics in children may vary considerably within a city, that it may increase with the degree of parental affluence, and that such affluence may reduce the utilization of penicillin V relative to other antibiotics.

Pathogenesis of Autoimmune Diseases: Antibodies Against Transglutaminase, Peptidylarginine Deiminase and Protein-bound Citrulline in Primary Sjögren’s Syndrome, Multiple Sclerosis and Alzheimer’s Disease

Coeliac disease (CD) is becoming a model for understanding the pathogenesis of autoimmune disorders. In CD, antibodies against transglutaminase 2 (TG2) and specific residues of gliadins have been identified. A similar situation is seen in rheumatoid arthritis (RA) with both anti‐citrullinated protein antibodies (ACPA) and auto‐antibodies against the citrullinating enzyme, peptidylarginine deiminase (PAD). Previously, we have suggested that a complex between an enzyme and its modified substrate constitutes the neoantigen in autoimmune diseases. Our hypothesis is challenged by findings in patients of primary Sjögren’s syndrome (pSS) who do not express ACPA, but who have been reported to carry anti‐PAD. The aims of our investigation were to reproduce the study claiming the presence of anti‐PAD in pSS and screen for ACPA and antibodies against TG2 and PAD in pSS (n = 78), multiple sclerosis (MS) (n = 85) and Alzheimers disease (AD) (n = 79) using ELISA. With blood donors (n = 100) as controls, no increased occurrence of autoantibodies was found among the patient groups tested. Contrary to what has been published previously, patients with pSS do not express anti‐PAD. The hypothesis of a complex between an enzyme and its modified substrate constituting the neoantigen in autoimmune diseases is still valid. The prevalence of anti‐PAD, anti‐TG2 and ACPA is comparatively restricted. PAD and TG2 do not seem to be involved directly in autoimmune mechanisms in pSS, MS or AD.

Biochemical and Immuno-pathological Aspects of Tissue Transglutaminase in Coeliac Disease

Tissue transglutaminase (tTg) has been identified as the major autoantigen in coeliac disease (CD). ELISA methods have been developed for measuring the autoantibody. There are divergent reports on the effects of calcium on the antibody binding to tTg. Furthermore, zinc is a potent inhibitor of tTg. To better understand the role of transglutaminase in CD, we have studied the stability of commercial tTG, the effect of CD serum on tTg-activity and the effects of calcium and zinc on the antibody binding. The inclusion of calcium during the coating of the ELISA plates significantly increases the binding of the antibody, while zinc at physiological concentrations inhibits the binding. Moreover, our results show that commercial guinea pig liver Tg treated with calcium contains at least four major antigenic molecules and is a labile enzyme, which is degraded rapidly by contaminating proteases. Human serum contains anti-proteases that protect the enzyme. Probably, the labile character of commercial tTG explains the divergent reports on the effects of calcium on antibody binding. Finally, antibodies in serum from a CD patient do not seem to inhibit tTg activity. Hypothetically, low, intestinal Zn2+-levels facilitate Ca2+-activation of tTg, which deamidates gliadin. A complex between tTg and modified gliadin forms the antigen and triggers the immune reaction leading to manifest CD. Hypozincaemia secondary to villous atrophy aggravates the induced disease.

Utilisation of codeine and propoxyphene: geographic and demographic variations in prescribing, prescriber and recipient categories.

AbstractObjectives: To assess (1) whether the utilisation of codeine or propoxyphene differs among the three major Swedish cities (Stockholm, Göteborg and Malmö) and between urban and semirural areas; (2) if so, whether it co-varies with the utilisation of other potentially dependence-promoting drugs, benzodiazepines; (3) what influence age, gender and socioeconomic factors have on the prescribing of the two narcotic analgesics; and (4) whether different codeine-prescriber categories have different prescribing habits. Methods: In Sweden, all pharmacies are owned by one corporation, Apoteket AB. This corporation collects, stores and compiles statistics on all drug sales in Sweden, and data are available both on national, regional, county and municipal levels. The employed unit is defined daily dose (DDD) per 1000 inhabitants per day. Using the pharmacy computer system while dispensing a drug, prescription patterns can be elucidated. This system describes the number of drug items dispensed, drug amounts and age and gender of patients. Furthermore, data from another, ecological study were used to relate codeine and propoxyphene utilisation to that of benzodiazepines and to various socioeconomic data available from records of the city of Malmö. Results: The utilisation of analgesics in Sweden has increased during a 10-year period. The withdrawal of over-the-counter combinations containing aspirin and low-dose codeine in 1990 resulted only in a transient decrease of codeine use. The utilisation of codeine in Malmö and Göteborg was considerably higher than that in Stockholm and in the rest of Sweden, including the surroundings of Malmö. In Malmö and Göteborg, codeine was most often prescribed by private physicians to middle-aged persons, particularly women. Districts in Malmö with a high utilisation of codeine were associated with unfavourable socioeconomic conditions and a high utilisation of benzodiazepines. The utilisation pattern of propoxyphene showed less or no such deviations. Conclusion: The results suggest an inappropriate use of codeine in two major cities in Sweden.

Peptidylarginine deiminases and the pathogenesis of rheumatoid arthritis: a reflection of the involvement of transglutaminase in coeliac disease.

Post-translational modifications are associated with certain autoimmune diseases. For example, in the initial steps of coeliac disease (CD), transglutaminase type 2 (TG2) catalyzes a post-translational deamidation of specific glutamine residues in dietary gluten, resulting in antibodies against both modified gliadin and against TG2. Anti-TG2 has become a specific biomarker for CD. In rheumatoid arthritis (RA), the presence of antibodies against citrullinated peptides (ACPA) characterizes a distinct subset of this inflammatory disorder. Moreover, antibodies against the enzyme that catalyzes the citrullination (peptidylarginine deiminase; PAD) are found in RA. Their relation to disease severity indicates a possible pathogenetic role. Thus, in two major autoimmune diseases (CD and RA), antibodies are present against a post-translationally modified substrate and against the calcium-dependent thiol-enzyme (TG2 and PAD, respectively) responsible for the modification. This review highlights the similarities between the TGs and the PADs and their putative pathogenetic roles in autoimmune diseases. Possible mechanisms of the effects of cigarette smoking and alcohol consumption on RA are discussed. By reflecting the progress in CD, the pathogenesis of ACPA-positive RA can be hypothesized where expression and regulation of PADs play significant roles. Indeed, autoimmune diseases should be studied collectively as well as individually. The new insight may lead towards innovative pharmacotherapeutic principles.

The effects of lipophilic substances on the shape of erythrocytes demonstrated by a new in vitro-method

UNLABELLED Low aqueous solubility of lipophilic agents, such as free fatty acids, hampers proper in vitro demonstration of biological effects, yielding an ambiguous in vitro-in vivo correlation. We have therefore developed a method for evaluating the acute effects of lipophilic substances on the shape of erythrocytes and estimated EC(50) and Hill coefficient according to the sigmoidal E(max) model. The test substance dissolved in medium-chain triglyceride is coated on a polycarbonate slide which serves as a cover sheet of a Bürker chamber. Freshly collected finger-tip blood is diluted with autologous EDTA-plasma and introduced into the chamber. After 10min at 37 degrees C, the cells are photographed under microscope and the fractions of normal and defect cells are evaluated. No staining is needed and the cells are kept viable during the test period. With increasing chain length, fatty acids, aliphatic amines and alcohols all increased the fraction of defect erythrocytes in a concentration-dependent manner. The results indicate that several fatty acids are very potent in their acute actions on erythrocytes, and that this effect is due to chain length rather than conformation. CONCLUSION The technique offers a screening method for testing the harmful effects of small amounts of lipophilic substances on erythrocytes.

Autoimmune markers in lymphoid malignancies.

Chronic immune stimulation such as Helicobacter pylori (hp) infection, Sjögren’s syndrome or coeliac disease may initiate non‐Hodgkin lymphoma (NHL). The opposite (appearance of autoimmunity) has also been reported. The aim of this study was to describe the pattern of these immune markers in patients with lymphoid malignancies. Sera from 96 patients with NHL (median age 72, range 38–88, F/M 41/55) were analysed with ELISA to determine the frequency of antibodies against guinea pig (gp) and human recombinant (hr) transglutaminase type 2 (Tg2), and hr factor XIII subunit a* (part of the Tg‐family), extractable nuclear antigen (ENA), and hp. As hp antibodies decrease in younger age cohorts a sex‐ and age‐matched control group of 768 persons was used. The control population for transglutaminase antibodies consisted of 59 blood donors, (median 42 years, range 19–65) was analysed with a commercial kit. Gp‐Tg2‐IgG positivity was documented in 72% and hr‐Tg2‐IgG positivity in 15% (5% positive controls for both; P < 0.001 and ns, respectively). For IgA 3% had gp‐Tg2 and 4% hr‐Tg2 (5% in controls: ns for both). Anti‐FXIII‐IgA positivity was found in 22% (5% in controls; P = 0.03). Unspecific anti‐ENA‐IgG positivity was found in 24% (P < 0.001), while only 2% had specific ENA autoantibodies. Moreover, 36% were positive for anti‐hp‐IgG, while controls were positive in 54% (P < 0.001). The frequency of unspecific autoantibodies was increased. No differences could be noted in specific autoantibodies (hr‐Tg2‐IgA). In contrast, fewer than expected were anti‐hp‐positive. A defective immune response, similar to that in autoimmune diseases, could contribute to the pathogenesis of lymphoid malignancies.

Cellular factor XIII and peptidylarginine deiminase-catalysed citrullination in rheumatoid arthritis

Antibodies against citrullinated proteins (ACPA) have been reported in the order of 70% of all cases with rheumatoid arthritis (RA). The authors and other groups have also shown that approximately one third of the ACPA-positive RA-cases carry antibodies against the calcium-dependent thiol-enzyme which catalyses citrullination, namely peptidylarginine deiminase (PAD). These patients seem to suffer from a more severe form of RA. The presence of two distinct subsets of RA based on presence or …