Zinc and nitrate in the ground water and the incidence of Type 1 diabetes in Finland.

AIMS: In Finland, the risk of childhood Type 1 diabetes varies geographically. Therefore we investigated the association between spatial variation of Type 1 diabetes and its putative environmental risk factors, zinc and nitrates. METHODS: The association was evaluated using Bayesian modelling and the geo-referenced data on diabetes cases and population. RESULTS: Neither zinc nor nitrate nor the urban/rural status of the area had a significant effect on the variation in incidence of childhood Type 1 diabetes. CONCLUSIONS: The results showed that although there was no significant difference in incidence between rural and urban areas, there was a tendency to increasing risk of Type 1 diabetes with the increasing concentration of NO3 in drinking water. The fact that no significant effect was found may stem from the aggregated data being too crude to detect it.

Geochemistry of ground water and the incidence of acute myocardial infarction in Finland.

STUDY OBJECTIVE: To examine the association of spatial variation in acute myocardial infarction (AMI) incidence and its putative environmental determinants in ground water such as total water hardness, the concentration of calcium, magnesium, fluoride, iron, copper, zinc, nitrate, and aluminium. DESIGN: Small area study using Bayesian modelling and the geo-referenced data aggregated into 10 km x 10 km cells. SETTING: The population data were obtained from Statistics Finland, AMI case data from the National Death Register and the Hospital Discharge Register, and the geochemical data from hydrogeochemical database of Geological Survey of Finland. PARTICIPANTS: A total of 18 946 men aged 35-74 years with the first AMI attack in the years 1983, 1988, and 1993. MAIN RESULTS: One unit (in German degree degrees dH) increment in water hardness decreased the risk of AMI by 1%. Geochemical elements in ground water included in this study did not show a statistically significant effect on the incidence and spatial variation of AMI, even though suggestive findings were detected for fluoride (protective), iron and copper (increasing). CONCLUSIONS: The results of this study with more specific Bayesian statistical analysis confirm findings from earlier observations of the inverse relation between water hardness and coronary heart disease. The role of environmental geochemistry in the geographical variation of the AMI incidence should be studied further in more detail incorporating the individual intake of both food borne and water borne nutrients. Geochemical-spatial analysis provides a basis for the selection of areas suitable for such research.

The incidence of type 1 diabetes among children in Finland--rural-urban difference.

The aim of the study was to investigate the incidence of type 1 diabetes among children aged 14 years or under according to the level of urbanization of the place of residence of children at the time of diagnosis in Finland during 1987 to 1996. The analysis was carried out using a Bayesian approach and GIS. The incidence was the highest in the rural heartland areas while the increase in incidence was sharpest in urban areas. The level of urbanization seems to explain only a part of the spatial variation in the incidence in Finland. It is possible that some environmental risk factors for type 1 diabetes have been more prevalent in rural heartland areas than in the rest of the country. These factors might have increased in urban environments in Finland particularly during the first half of 1990s.

Bayesian analysis of geographical variation in the incidence of Type I diabetes in Finland.

AIMS/HYPOTHESIS: In Finland, the incidence of Type I (insulin-dependent) diabetes mellitus among children aged 14 years or under is the highest in the world. The increase in incidence is approximately 3% per year. A marked geographical variation in incidence was reported in Finland during the late 1980s. Our aim was to explore the most recent regional pattern in incidence of Type I diabetes in Finland. METHODS: Data on the nationwide incidence of childhood diabetes in Finland was obtained from the Prospective Childhood Diabetes Registry for the periods 1987-1991 and 1992-1996. Population data was obtained from the National Population Registry. The geographical pattern of incidence was studied applying a Bayesian hierarchical approach and Geographical Information Systems. The inferences from the data was based on the estimated geographical intensity of diabetes. RESULTS: There was a clear evidence of geographic variation for the risk of childhood diabetes during the entire 10-year period. The high-risk areas were found in the wide belt crossing the central part of Finland. Comparison of the estimated intensity of diabetes between the two 5-year periods showed that the geographical pattern of diabetes risk has changed over time. Our analyses also confirmed the existence of a few persistent high-risk and low-risk areas in Finland. CONCLUSION/INTERPRETATION: The finding of high-risk areas of childhood Type I diabetes suggests that specific genetic or environmental risk factors have become greater in certain geographic locations in Finland.

Superior formation of cortical memory traces for melodic patterns in musicians.

The human central auditory system has a remarkable ability to establish memory traces for invariant features in the acoustic environment despite continual acoustic variations in the sounds heard. By recording the memory-related mismatch negativity (MMN) component of the auditory electric and magnetic brain responses as well as behavioral performance, we investigated how subjects learn to discriminate changes in a melodic pattern presented at several frequency levels. In addition, we explored whether musical expertise facilitates this learning. Our data show that especially musicians who perform music primarily without a score learn easily to detect contour changes in a melodic pattern presented at variable frequency levels. After learning, their auditory cortex detects these changes even when their attention is directed away from the sounds. The present results thus show that, after perceptual learning during attentive listening has taken place, changes in a highly complex auditory pattern can be detected automatically by the human auditory cortex and, further, that this process is facilitated by musical expertise.

Small-area variation in mortality in the city of Oulu, Finland, during the period 1978--1995.

The aim of the present work was to explore small-area differences in mortality from all causes among males and females within the city of Oulu during the period 1978--1995 and to identify areas where mortality has been persistently high or low. Analyses carried out using Geographical Information System techniques with geo-referenced mortality data produced at a resolution of 1 x 1 km showed significant regional variations in mortality within the city. The differences were wide enough to suggest variations of several years in longevity, and were probably indicative of marked variations in the incidences of diseases. Observed mortality differences may reflect the influence of the rapidly changing urban structure and consequent health effects based on selection, lifestyles, work exposures and deprivation.

A bovine dander allergen, comparative modeling, and similarities and differences in folding with related proteins.

The most important allergenic protein in cow dander and urine is Bos d 2. It is proposed to belong to the family of lipocalins, which are proteins capable of binding small hydrophobic molecules. The allergenic properties of Bos d 2 indicate an interaction between the accessible regions of the native protein and IgE. In this work, a three-dimensional model was created for Bos d 2 by comparative modeling, and features characteristic of outlier lipocalins were observed. The protruding regions of the surface were characterized and used in predicting the possible B-cell epitopes. There is a pocket inside the core and its size is appropriate for small molecules. The model shows a hydrophilic amino acid side chain of glutamic acid 115 on the inner surface of the hole and a phenylalanine as the "gatekeeper" instead of tyrosine, which is common in experimentally modeled lipocalins.

Tissue localization of bovine dander allergen Bos d 2.

BACKGROUND: Domestic mammals are important sources of indoor allergens. However, the origin at the tissue level and the biologic function of mammalian allergens are largely unknown. OBJECTIVE: The aim of this study was to localize the source of the major bovine dander allergen, Bos d 2, in bovine tissues. METHODS: Samples from several organs were tested for the presence of mRNA encoding Bos d 2 and Bos d 2 protein by using the reverse transcriptase polymerase chain reaction and immunohistochemical staining, respectively. RESULTS: Skin proved to be the only tissue where mRNA encoding Bos d 2 was detected. This observation was confirmed by immunohistochemistry with a monoclonal anti-Bos d 2 antibody as the primary antibody. In the skin sections, Bos d 2 was found in the secretory cells of apocrine sweat glands and the basement membranes of the epithelium and hair follicles. Bos d 2 belongs to the family of lipocalins comprising a number of pheromone carrier proteins that are present, for example, in the secretions of the apocrine sweat glands. CONCLUSION: Together with earlier data, our findings suggest that Bos d 2 is produced in sweat glands and transported to the skin surface as a carrier of the pheromone ligand. Because dander allergens of a number of mammalian species are lipocalins, the common biologic function of being pheromone carriers seems to be a common feature of an important group of aeroallergens.

Recombinant allergen fragments as candidate preparations for allergen immunotherapy.

BACKGROUND: Lately, renewed interest has arisen in the new forms of allergen immunotherapy because they may offer alternatives for drug treatment. OBJECTIVE: The purpose of this study was to develop a well-characterized preparation of the main respiratory cow dander allergen, Bos d 2, with attenuated allergenic activity. METHODS: The immunologic characteristics of Bos d 2 preparations were studied by indirect IgE ELISA, ELISA inhibition, Western blotting, histamine release, skin prick tests, and the proliferation tests of allergen-specific T-cell clones. RESULTS: The complete recombinant Bos d 2 was observed to bind effectively, IgE of cow-allergic patients in indirect ELISA. In other experiments, the IgE-binding capacity of recombinant Bos d 2 proved to be lower compared with native Bos d 2. When the two overlapping recombinant fragments of Bos d 2 (corresponding amino acids 1-131 and 81-172, respectively) covering the whole molecule were compared with the complete recombinant Bos d 2 with several methods, only a low level of residual reactivity was observed. For example, recombinant fragments could not bind antibody at all in ELISA inhibition tests retaining, however, some reactivity in skin prick tests. In contrast, the fragments were able to stimulate vigorously Bos d 2-specific T-cell clones. CONCLUSION: The approach we have taken may offer a simple and reproducible way to produce hypoallergenic preparations for immunotherapy, circumventing simultaneously some of the problems of other experimental methods such as individual T-cell epitope recognition in peptide-based immunotherapy.

Restricted onset of T cell receptor alpha gene rearrangement in fetal and neonatal thymocytes.

The initial T cell receptor (TCR) alpha gene rearrangements were analyzed in fetal and neonatal thymocyte hybridomas by Southern blotting. Interestingly, in 30% of all thymocyte hybridomas and in all fetal day 16 thymocyte hybridomas the most proximal J alpha 50 (psi J alpha) gene was rearranged. This rearrangement was found on one chromosome only and mostly in association with a delta rearrangement on the homologous chromosome. J alpha 50 was rearranged to multiple target genes based on the variable size of the restriction fragments. In addition, delta rearrangement was found with a concomitant alpha rearrangement in the majority of hybridomas and it was not only associated with J alpha 50 but with several other rearranged J alpha genes as well. Our results clearly demonstrate that T cell precursors are not pre-committed to either delta or alpha rearrangement but a flexible progenitor responds to multiple regulatory signals during T cell differentiation and they do not support the notion that delta rec-psi J alpha rearrangement is required for cell commitment to TCR alpha gene rearrangement.

Molecular analysis of allergenic proteins in bovine dander.

An analytic procedure was established to characterize bovine dander proteins with allergenic properties. The proteins from dander extract were separated by size-exclusion gel filtration, and the fractions were studied with SDS-PAGE followed by immunoblotting. An 11-kDa allergen was found in the same gel filtration fractions as 20- and 22-kDa allergens, and this suggests that the 11-kDa allergen is a dimer in its native form. Our method also detected two separate 22-kDa allergens. The primary structure of the major bovine dander allergen (BDA20) was also studied. A protein sequencer was used to determine the amino acid sequences of enzymatically cleaved peptides. The homology searches revealed that BDA20 is not a previously known bovine protein.

Complementary DNA cloning of the predominant allergen of bovine dander: a new member in the lipocalin family.

BACKGROUND: A number of allergenic proteins in animal danders have been characterized at the molecular level, but little is known of their biologic functions. We have found that the prevalence of IgE antibodies among patients with cattle-associated asthma is highest against a dander protein referred to as BDA20. OBJECTIVE: The study was performed to characterize the molecular structure of BDA20,* the predominant allergen in bovine dander. METHODS: Clones encoding allergens were identified and isolated from a complementary DNA library by immunoblotting and DNA hybridization and sequenced. Recombinant proteins were produced in Escherichia coli. Immunoreactivity of the recombinant proteins and amino acid sequences of peptides obtained from native BDA20 after Lys-C cleavage were used to identify clones coding for BDA20. RESULTS: In this article we report the cDNA and amino acid sequences of BDA20. Homology comparisons showed that BDA20 belongs to the family of lipocalins. CONCLUSIONS: The results link a dander allergen to a group of functionally important proteins. Lipocalins are present in various body fluids and secretions of several animal species in which they function as carriers of small hydrophobic molecules, such as retinoids and pheromones. If allergenicity proves to be a property shared by lipocalins, our results will have considerable implications for allergen research.

Immune reactivity of cow-asthmatic dairy farmers to the major allergen of cow (BDA20) and to other cow-derived proteins. The use of purified BDA20 increases the performance of diagnostic tests in respiratory cow allergy.

BACKGROUND: Cow dust is one of the most important inducers of occupational allergic diseases in Finland. For example, in 1991 it accounted for almost 40% of the new occupational asthma cases. OBJECTIVE: This study compares the performance of the purified major cow allergen (BDA20) and crude bovine epithelial extract (BEA) in diagnostic tests and examines the role of milk allergy-associated bovine proteins (bovine serum albumin, alpha-lactalbumin, beta-lactoglobulin, casein) in respiratory cow allergy. METHODS: The humoral responses of cow-asthmatic and healthy farmers to the various components of BEA were analysed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The levels of specific IgE and IgG antibodies were quantificated with enzyme-linked immunosorbent assays (ELISAs). The cellular responses were analysed with antigen-specific lymphocyte proliferation tests. RESULTS: The specific anti-BDA20 IgE measurement was found to be best in distinguishing between the asthmatic farmers and their healthy colleagues. It proved possible to determine a cut-off value that gave the analysis a specificity and sensitivity of 100%; the distinction between the two groups was highly significant (P < 0.0001). In the lymphocyte proliferation analysis, cow asthma was more closely associated with reactivity to BDA20 than to BEA. In the measurement of anti-BDA20 and anti-BEA IgG antibody levels, considerable overlap between the groups was observed, suggesting that these antibodies are not directly involved in cow allergy. When proteins associated with milk allergy were used as test reagents, no statistically significant differences could be observed between the groups, except for anti-casein IgE antibodies the level of which, however, overlapped considerably between the farmer groups. CONCLUSION: These findings suggest that purified BDA20 is better than BEA for diagnosing cow asthma and that proteins associated with milk allergy are of only marginal significance in this disease.

cDNA cloning and protein analysis of a bovine dermal allergen with homology to psoriasin.

Immunoscreening of a cDNA library from bovine skin led to isolation of clones coding for an allergen named BDA11. Sequence analysis of the clones revealed that they can encode a protein of 11.6 kDa with a predicted pI of 5.19. Allergenicity of BDA11 was verified by the IgE reactivity in cattle-allergic patients' sera with the recombinant protein produced in Escherichia coli. A biochemically purified native allergen of 11 kDa from bovine dander was identified as BDA11 by peptide sequencing. Homology comparisons showed that BDA11 had a 63.4% amino acid identity with human psoriasin. Psoriasin is a calcium-binding protein expressed in keratinocytes, and it is strongly up-regulated in psoriatic skin. BDA11 also had segments homologous with calcium-binding proteins from three other species.

Homology of a bovine allergen and the oligomycin sensitivity-conferring protein of the mitochondrial adenosine triphosphate synthase complex.

We have characterized bovine allergens by constructing and analyzing a complementary DNA library from bovine skin. Clones producing proteins that reacted with IgE antibodies from persons with allergy were purified and sequenced. One set of the allergen-coding clones showed an almost complete homology with the bovine oligomycin sensitivity-conferring protein of the mitochondrial adenosine triphosphate synthase complex. The IgE antibodies adsorbed with the recombinant allergen reacted with an 11 kd protein in the cow dander extract. Binding of the IgE from patients allergic to the recombinant allergen expressed in Escherichia coli confirmed the allergen-coding ability of the complementary DNA sequence. The prevalence of the IgE-positive sera among patients with cow allergy and control subjects suggests that the recombinant allergen represents one of the minor allergens in cow dander. This is the first time a mammalian allergen has been identified as a protein with a known function.

Quantification of a major bovine allergen by a two-site immunometric assay based on monoclonal antibodies.

A two-site immunometric assay based on monoclonal antibodies (mAb) was developed for the measurement of a 20-kDa major allergen of cow. The sensitivity of this assay was (BDA20) 1 ng/ml. It was used to measure airborne allergen concentrations in 10 Finnish cowsheds. The mean concentration of the BDA20 measured at two stationary sites was 280 ng/m3. Concentrations varied more than 10-fold among cowsheds (54-804 ng/m3). The mean intertest coefficient of variation was 8.2%, and the mean intratest variation 4.1%.

Evidence for recombinatorial hot spots at the T cell receptor J alpha locus.

The complex genomic organization of the murine T cell receptor (TcR) delta-alpha region has hindered detailed studies of alpha gene rearrangement and J alpha gene usage in individual differentiating T cell precursors. We have isolated a novel set of J alpha probes which, in combination with a few restriction enzyme digests, enable a reliable, simple and nearly complete analysis and location of any rearrangement at the J alpha locus by conventional Southern blotting. The probes were used to analyze TcR alpha gene rearrangements in T cell hybridomas derived from an in vitro culture system that supports T cell differentiation of bone marrow cells. Our results indicate that J alpha genes are unequally accessible for rearrangement and two hot spots for rearrangement could be demonstrated. In addition, only a restricted set of J alpha genes was rearranged in each culture indicating that the slightly variable composition of factors can influence the recombinatorial accessibility of J alpha genes. The hot spots for rearrangement were not only limited to T cells differentiating in vitro but could also be demonstrated among functional T cell clones based on the published sequence information from isolated TcR alpha gene rearrangements. The demonstration and the location of the hot spots for rearrangement in the T cell differentiation culture system opens up the possibility to study factors and mechanisms that regulate recombinatorial accessibility of TcR alpha genes.

Integration of bovine papillomavirus type 1 DNA and analysis of the amplified virus-cell junctions in transformed primary mouse fibroblasts.

We have analysed the site of bovine papillomavirus type 1 (BPV-1) DNA integration in clones originating from a transformed primary mouse fibroblast cell line established by transfection of linear BPV-1 DNA. Viral DNA was integrated at a single site in the host genome with an intact early region and an almost complete long control region. Sequence analysis showed that the BPV-1 DNA was integrated at the HindIII site (the enzyme used to linearize the BPV-1 DNA for transfection) with short deletions at both ends. These deletions correspond to a 534 bp segment spanning the 3' end of the L1 open reading frame and the replication enhancer element in the BPV-1 genome. The cellular sequences 5' to the viral integration site exhibited 85 to 97% identity to several sequences belonging to the mouse L1 family of long interspersed repetitive sequences. Cellular sequences 3' to the viral DNA exhibited no significant similarity to any known sequence. The BPV-1 sequences and the cellular flanking sequences were found to be amplified 45- to 50-fold. All the cell clones shared an identical integration site but one of the clones had an additional population of amplified and integrated BPV-1 DNA molecules with an internal deletion of 1136 bp in the late region. The significance of viral DNA integration at a murine long interspersed repetitive sequence containing an amplification-promoting sequence is discussed.

Golytely preparation for colonoscopy: 1.5 liters is enough for outpatients.

In a prospective double-blind study of the effectiveness and patient acceptance of Golytely whole-gut preparation for colonoscopy, 50 consecutive patients were randomly allocated to drink either 1.5 l (Group I) or 3 l (Group II). The patients had some slight dietary restrictions, and received mild laxatives on the preceding day. The cleansing result did not differ significantly in the two groups. The result was assessed as "good" in 76% of cases in Group I (95% confidence limits 55-91%) and in 83% of cases in Group II (95% confidence limits 63-95%). In half of the remaining cases in both groups the result was "acceptable" and in the other half "poor". Patient acceptance did not differ significantly in the two groups. After completion of the randomized study, oral cleansing with 1.5 l Golytely has been our daily routine. In 42 patients so treated quality of cleansing was good in 81% (95% confidence limits 66-91%), acceptable in 12%, and poor in 7%.