Biophysical characterization of SARAH domain-mediated multimerization of Hippo pathway complexes in Drosophila.

Hippo pathway signaling limits cell growth and proliferation and maintains the stem-cell niche. These cellular events result from the coordinated activity of a core kinase cassette that is regulated, in part, by interactions involving Hippo, Salvador, and dRassF. These interactions are mediated by a conserved coiled-coil domain, termed SARAH, in each of these proteins. SARAH domain-mediated homodimerization of Hippo kinase leads to autophosphorylation and activation. Paradoxically, SARAH domain-mediated heterodimerization between Hippo and Salvador enhances Hippo kinase activity in cells, whereas complex formation with dRassF inhibits it. To better understand the mechanism by which each complex distinctly modulates Hippo kinase and pathway activity, here we biophysically characterized the entire suite of SARAH domain-mediated complexes. We purified the three SARAH domains from Drosophila melanogaster and performed an unbiased pulldown assay to identify all possible interactions, revealing that isolated SARAH domains are sufficient to recapitulate the cellular assemblies and that Hippo is a universal binding partner. Additionally, we found that the Salvador SARAH domain homodimerizes and demonstrate that this interaction is conserved in Salvador's mammalian homolog. Using native MS, we show that each of these complexes is dimeric in solution. We also measured the stability of each SARAH domain complex, finding that despite similarities at both the sequence and structural levels, SARAH domain complexes differ in stability. The identity, stoichiometry, and stability of these interactions characterized here comprehensively reveal the nature of SARAH domain-mediated complex formation and provide mechanistic insights into how SARAH domain-mediated interactions influence Hippo pathway activity.

Molecular-Level Simulations of Turbulence and Its Decay.

We provide the first demonstration that molecular-level methods based on gas kinetic theory and molecular chaos can simulate turbulence and its decay. The direct simulation Monte Carlo (DSMC) method, a molecular-level technique for simulating gas flows that resolves phenomena from molecular to hydrodynamic (continuum) length scales, is applied to simulate the Taylor-Green vortex flow. The DSMC simulations reproduce the Kolmogorov -5/3 law and agree well with the turbulent kinetic energy and energy dissipation rate obtained from direct numerical simulation of the Navier-Stokes equations using a spectral method. This agreement provides strong evidence that molecular-level methods for gases can be used to investigate turbulent flows quantitatively.

Bilateral filtering using the full noise covariance matrix applied to x-ray phase-contrast computed tomography.

The purpose of this work is to develop an image-based de-noising algorithm that exploits complementary information and noise statistics from multi-modal images, as they emerge in x-ray tomography techniques, for instance grating-based phase-contrast CT and spectral CT. Among the noise reduction methods, image-based de-noising is one popular approach and the so-called bilateral filter is a well known algorithm for edge-preserving filtering. We developed a generalization of the bilateral filter for the case where the imaging system provides two or more perfectly aligned images. The proposed generalization is statistically motivated and takes the full second order noise statistics of these images into account. In particular, it includes a noise correlation between the images and spatial noise correlation within the same image. The novel generalized three-dimensional bilateral filter is applied to the attenuation and phase images created with filtered backprojection reconstructions from grating-based phase-contrast tomography. In comparison to established bilateral filters, we obtain improved noise reduction and at the same time a better preservation of edges in the images on the examples of a simulated soft-tissue phantom, a human cerebellum and a human artery sample. The applied full noise covariance is determined via cross-correlation of the image noise. The filter results yield an improved feature recovery based on enhanced noise suppression and edge preservation as shown here on the example of attenuation and phase images captured with grating-based phase-contrast computed tomography. This is supported by quantitative image analysis. Without being bound to phase-contrast imaging, this generalized filter is applicable to any kind of noise-afflicted image data with or without noise correlation. Therefore, it can be utilized in various imaging applications and fields.

Procalcitonin (PCT)-guided algorithm reduces length of antibiotic treatment in surgical intensive care patients with severe sepsis: results of a prospective randomized study.

BACKGROUND: Adequate indication and duration of administration are central issues of modern antibiotic treatment in intensive care medicine. The biochemical variable procalcitonin (PCT) is known to indicate systemically relevant bacterial infections with high accuracy. In the present study, we aimed to investigate the clinical usefulness of PCT for guiding antibiotic treatment in surgical intensive care patients with severe sepsis. PATIENTS AND METHODS: Patients were randomly assigned to a PCT-guided or a control group requiring antibiotic treatment. All patients received a calculated antibiotic regimen according to the presumed microbiological spectrum. In the PCT-guided group, antibiotic treatment was discontinued if clinical signs of infection improved and the PCT value was either <1 ng/ml or decreased to <35% of the initial concentration within three consecutive days. In the control group, antibiotic treatment was directed by empirical rules. RESULTS: The PCT-guided group (n = 14 patients) and the control group (n = 13 patients) did not differ in terms of biological variables, underlying diseases, and overall disease severity. PCT guidance led to a significant reduction of antibiotic treatment from 6.6 +/- 1.1 days (mean +/- SD) compared with 8.3 +/- 0.7 days in control patients (p < 0.001) along with a reduction of antibiotic treatment costs of 17.8% (p < 0.01) without any adverse effects on outcome. CONCLUSIONS: Monitoring of PCT is a helpful tool for guiding antibiotic treatment in surgical intensive care patients with severe sepsis. This may contribute to an optimized antibiotic regimen with beneficial effects on microbial resistances and costs in intensive care medicine.

Motion-compensated iterative cone-beam CT image reconstruction with adapted blobs as basis functions.

This paper presents a three-dimensional method to reconstruct moving objects from cone-beam X-ray projections using an iterative reconstruction algorithm and a given motion vector field. For the image representation, adapted blobs are used, which can be implemented efficiently as basis functions. Iterative reconstruction requires the calculation of line integrals (forward projections) through the image volume, which are compared with the actual measurements to update the image volume. In the existence of a divergent motion vector field, a change in the volumes of the blobs has to be taken into account in the forward and backprojections. An efficient method to calculate the line integral through the adapted blobs is proposed. It solves the problem, how to compensate for the divergence in the motion vector field on a grid of basis functions. The method is evaluated on two phantoms, which are subject to three different known motions. Moreover, a motion-compensated filtered back-projection reconstruction method is used, and the reconstructed images are compared. Using the correct motion vector field with the iterative motion-compensated reconstruction, sharp images are obtained, with a quality that is significantly better than gated reconstructions.

Alcohol dehydrogenase 1B (ADH1B) genotype, alcohol consumption and breast cancer risk by age 50 years in a German case-control study.

In a population-based study of 613 cases and 1082 controls, alcohol dehydrogenase 1B (ADH1B) genotype was not an independent risk factor for breast cancer, although the possibility was raised that it modifies risk associated with high levels of alcohol consumption (OR 1.1, 95% confidence interval (CI) 0.8-1.6 for ADH1B*1/*1 genotype vs 0.2, 95% CI 0.1-1.0 for ADH1B*2 carriers).

Bacillus anthracis genetics and virulence gene regulation.

The Bacillus anthracis genome consists of an approximately 5.3-Mb chromosome and two plasmids, pXO1 (182 kb) and pXO2 (96 kb). Genetic analysis has focused primarily on the structural genes for the anthrax toxin proteins, pagA, lef, and cya, the biosynthetic genes for capsule synthesis, capB, capC, and capA, and a gene associated with depolymerization of capsule, dep. The three toxin genes are located at distinct loci on pXO1, while the cap and dep genes are arranged in an apparent operon on pXO2. Additional genes that may play a role in B. anthracis virulence include the germination operon gerX and the general stress transcription factor sigB. Host-related signals affecting transcription of the toxin and capsule genes include temperature (37 degrees C) and bicarbonate/CO2. The B. anthracis plasmids carry two regulatory genes that share little sequence similarity with regulators in other bacteria. The pXO1-encoded gene atxA positively controls expression of the toxin and capsule genes, and has been implicated in control of other genes of unknown function. atxA mutants are avirulent in mice, and mice infected with atxA-null strains show a decreased immunological response to the toxin proteins. The pXO2-encoded regulator, acpA, shares sequence similarity with atxA. Yet acpA function appears to be restricted to positive control of capsule gene expression. The chromosomal gene abrB, a homologue of a well-characterized B. subtilis transition state regulator, controls growth phase-specific transcription of the toxin genes. Genetic manipulation of B. anthracis can be achieved by using natural means of DNA transfer and by electroporation of recombinant DNAs into B. anthracis. Genetic exchange can occur between B. anthracis strains and between B. anthracis and closely-related species. Although pXO1 and pXO2 are not self-transmissible, these plasmids and others can be transferred by conjugative plasmids originating in B. thuringiensis. Generalized transducing phage that permit inter-species transfer of chromosomal and plasmid DNA have also been described.

mdm2 mRNA level is a prognostic factor in soft tissue sarcoma.

BACKGROUND: The oncogenic properties of murine double minute-2 (mdm2) protein over-expression, which mostly results from the interaction with the tumor suppressor p53, are well described and their negative impacts on the prognosis of affected patients is well characterized. However, clinical relevance of mdm2 mRNA expression is poorly investigated. MATERIALS AND METHODS: In this study, 65 soft tissue sarcoma (STS) samples were analyzed for mdm2 mRNA expression by a quantitative reverse transcription polymerase chain reaction (RT-PCR) approach using available validated ready-to-use assays based on the TaqMan technology (PE Applied Biosystems, Weiterstadt, Germany). Mdm2 data were correlated to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression calculated from the same sample. RESULTS: For patients with a mdm2/GAPDH mRNA ratio below 50 zmol/amol the survival was strikingly reduced in comparison to patients with a ratio of > or =50 (p = 0.0241). Multivariate Cox analysis showed that the difference in prognosis for patients with tumor stage 2 and 3 became even more pronounced between patients with a ratio of <50 zmol/amol and patients with a ratio of > or =50 (p = 0.0041; RR = 5.6). To test if the group with an mdm2 mRNA expression > or =50 is homogenous concerning the prognosis, the group was divided into three subgroups with values of 50 to <100, 100 to <500 and > or =500. The subgroup with values of 100 to <500 showed the best prognosis (p = 0.0164); whereas, the one with values of 50 to <100 showed the worst prognosis in this group and, in between, was the one with values of > or =500. After omitting patients of stage 1 and 4, the subgroup with values of 100 to <500 showed an even more striking best prognosis (p = 0.0015); the other subgroups remained in the same sequence. The risk of tumor-related death over 5 years was most conspicuous in patients with mdm2 mRNA expression <50 than in those with ratios of 100 to <500 displaying a 13.3-fold higher risk. In a comparison between mdm2 mRNA levels and P53 protein expression or p53 mutational status, no relationship was found. CONCLUSIONS: In our study, the mdm2 mRNA level appears to be an independent prognostic factor for STS patients, marking its role in STS genesis and as a potential factor for gene therapeutical approaches.

Early Bacillus anthracis-macrophage interactions: intracellular survival survival and escape.

This study describes early intracellular events occurring during the establishment phase of Bacillus anthracis infections. Anthrax infections are initiated by dormant endospores gaining access to the mammalian host and becoming engulfed by regional macrophages (Mphi). During systemic anthrax, late stage events include vegetative growth in the blood to very high titres and the synthesis of the anthrax exotoxin complex, which causes disease symptoms and death. Experiments focus on the early events occurring during the first few hours of the B. anthracis infectious cycle, from endospore germination up to and including release of the vegetative cell from phagocytes. We found that newly vegetative bacilli escape from the phagocytic vesicles of cultured Mphi and replicate within the cytoplasm of these cells. Release from the Mphi occurs 4-6 h after endospore phagocytosis, timing that correlates with anthrax infection of test animals. Genetic analysis from this study indicates that the toxin plasmid pXO1 is required for release from the Mphi, whereas the capsule plasmid pXO2 is not. The transactivator atxA, located on pXO1, is also found to be essential for release, but the toxin genes themselves are not required. This suggests that Mphi release of anthrax bacilli is atxA regulated. The putative 'escape' genes may be located on the chromosome and/or on pXO1.

Sequence and organization of pXO1, the large Bacillus anthracis plasmid harboring the anthrax toxin genes.

The Bacillus anthracis Sterne plasmid pXO1 was sequenced by random, "shotgun" cloning. A circular sequence of 181,654 bp was generated. One hundred forty-three open reading frames (ORFs) were predicted using GeneMark and GeneMark.hmm, comprising only 61% (110,817 bp) of the pXO1 DNA sequence. The overall guanine-plus-cytosine content of the plasmid is 32.5%. The most recognizable feature of the plasmid is a "pathogenicity island," defined by a 44.8-kb region that is bordered by inverted IS1627 elements at each end. This region contains the three toxin genes (cya, lef, and pagA), regulatory elements controlling the toxin genes, three germination response genes, and 19 additional ORFs. Nearly 70% of the ORFs on pXO1 do not have significant similarity to sequences available in open databases. Absent from the pXO1 sequence are homologs to genes that are typically required to drive theta replication and to maintain stability of large plasmids in Bacillus spp. Among the ORFs with a high degree of similarity to known sequences are a collection of putative transposases, resolvases, and integrases, suggesting an evolution involving lateral movement of DNA among species. Among the remaining ORFs, there are three sequences that may encode enzymes responsible for the synthesis of a polysaccharide capsule usually associated with serotype-specific virulent streptococci.

Sequence, assembly and analysis of pX01 and pX02.

Bacillus anthracis plasmids pX01 and pX02, harboured by the Sterne and Pasteur strains, respectively, have been sequenced by random 'shotgun' cloning and high throughout sequence analysis. These sequences have been assembled (Sequencher) to generate a circulate pX01 plasmid containing 181 656 bp and a single linear (gapped) pX02 contig containing at least 93.479 bp. Initial annotation suggests that the two plasmids combined contain at least 200 potential open reading frames (ORFs) with < 40% having significant similarity to sequences registered in open databases. Collectively, only 118 566 bp of the pX01 DNA (65%) represent predicted coding regions. This value is similar to published gene densities for other plasmids and is indicative of the larger intergenic spaces in plasmids vs those found in the chromosomes of the parental microbes (85-93% gene density). A 70 kbp region including the toxin genes (cya, lef and pag) is distinct from the remainder of the pX01 sequence: (1) it has a lower gene density (58 vs 70%) than the remaining 111 kbp; (2) it contains all but one of the co-regulated transcriptional fusions identified by transposon mutagenesis (Hoffmaster & Koehler 1997) and (3) it contains a significantly higher proportion of positive BLAST scores (62 vs 20%) for putative ORFs. These data suggest different origins for the two regions of pX01.

Control of virulence gene expression in Bacillus anthracis.

The atxA gene is an important regulator of virulence gene expression in Bacillus anthracis. atxA positively regulates expression of the three genes encoding the anthrax toxin proteins and at least one gene is required for capsule production. Here we report that an atxA-null mutant exhibits phenotypes unrelated to toxin and capsule synthesis. An atxA-null mutant grows poorly on minimal media and sporulates more efficiently than the parent strain. Numerous transposon-generated promoter-lacZ fusions at distinct loci on pXO1 exhibit CO2-enhanced atxA-dependent expression similar to that observed for the toxin genes. We also report that the atxA-activated pagA gene (encoding the protective antigen toxin protein) is co-transcribed with a 300-bp gene, pagR, located downstream of pagA. The predicted protein product of pagR has some amino acid sequence similarity to transcriptional regulators in other organisms. Our data indicate that pagR represses expression of pagA and atxA. pagR also controls expression of some CO2/atxA-activated transcriptional fusions on pXO1 that do not correspond to the toxin genes. Regulation of these fusions and pagA and pagR may be due to changes in AtxA levels, or may be independent of atxA expression.

Autogenous regulation of the Bacillus anthracis pag operon.

Protective antigen (PA) is an important component of the edema and lethal toxins produced by Bacillus anthracis. PA is essential for binding the toxins to the target cell receptor and for facilitating translocation of the enzymatic toxin components, edema factor and lethal factor, across the target cell membrane. The structural gene for PA, pagA (previously known as pag), is located on the 182-kb virulence plasmid pXO1 at a locus distinct from the edema factor and lethal factor genes. Here we show that a 300-bp gene located downstream of pagA is cotranscribed with pagA and represses expression of the operon. We have designated this gene pagR (for protective antigen repressor). Two pagA mRNA transcripts were detected in cells producing PA: a short, 2.7-kb transcript corresponding to the pagA gene, and a longer, 4.2-kb transcript representing a bicistronic message derived from pagA and pagR. The 3' end of the short transcript mapped adjacent to an inverted repeat sequence, suggesting that the sequence can act as a transcription terminator. Attenuation of termination at this site results in transcription of pagR. A pagR mutant exhibited increased steady-state levels of pagA mRNA, indicating that pagR negatively controls expression of the operon. Autogenous control of the operon may involve atxA, a trans-acting positive regulator of pagA. The steady-state level of atxA mRNA was also increased in the pagR mutant. The mutant phenotype was complemented by addition of pagR in trans on a multicopy plasmid.

The anthrax toxin activator gene atxA is associated with CO2-enhanced non-toxin gene expression in Bacillus anthracis.

The Bacillus anthracis toxin genes, cya, lef, and pag, can be viewed as a regulon, in which transcription of all three genes is activated in trans by the same regulatory gene, atxA, in response to the same signal, CO2. In atxA+ strains, toxin gene expression is increased 5- to 20-fold in cells grown in 5% CO2 relative to cells grown in air. CO2-enhanced toxin gene transcription is not observed in atx4-null mutants. Here, we used two independent techniques to obtain evidence for additional CO2-induced atxA-regulated genes. First, total protein preparations from atxA4+ and atxA isolates grown in 5% CO2 and in air were examined by two-dimensional electrophoresis. Comparison of the resulting protein patterns indicated that synthesis of non-toxin proteins is influenced by growth in elevated CO2 and the toxin gene regulator, atxA. Second, we generated random transcriptional lacZ fusions in B. anthracis with transposon Tn917-LTV3. Transposon-insertion libraries were screened for mutants expressing CO2-enhanced atxA-dependent beta-galactosidase activity. DNA sequence analysis of transposon insertion sites in 17 mutants carrying CO2- and atxA-regulated fusions revealed 10 mutants carrying independent insertions on the 185-kb toxin plasmid pXO1 which did not map to the toxin genes. The tcr-lacZ fusion mutants (tcr for toxin coregulated) were Tox+, indicating that these genes may not be involved in anthrax toxin gene activation. Our data indicate a clear association of atxA with CO2-enhanced gene expression in B. anthracis and provide evidence that atxA regulates genes other than the structural genes for the anthrax toxin proteins.

Regulation of anthrax toxin activator gene (atxA) expression in Bacillus anthracis: temperature, not CO2/bicarbonate, affects AtxA synthesis.

Anthrax toxin gene expression in Bacillus anthracis is dependent on the presence of atxA, a trans-acting regulatory gene located on the resident 185-kb plasmid pXO1. In atxA+ strains, expression of the toxin genes (pag, lef, and cya) is enhanced by two physiologically significant signals: elevated CO2/bicarbonate and temperature. To determine whether increased toxin gene expression in response to these signals is associated with increased atxA expression, we monitored steady-state levels of atxA mRNA and AtxA protein in cells cultured in different conditions. We purified histidine-tagged AtxA [AtxA(His)] from Escherichia coli and used anti-AtxA(His) serum to detect AtxA in protein preparations from B. anthracis cells. AtxA was identified as a protein with an apparent size of 56 kDa in cytoplasmic fractions of B. anthracis cells. Our data indicate that atxA expression is not influenced by CO2/bicarbonate levels. However, the steady-state level of atxA mRNA in cells grown in elevated CO2/bicarbonate at 37 degrees C is five- to sixfold higher than that observed in cells grown in the same conditions at 28 degrees C. A corresponding difference in AtxA protein was also seen at the different growth temperatures. When atxA was cloned on a multicopy plasmid in B. anthracis, AtxA levels corresponding to the atxA gene copy number were observed. However, this strain produced significantly less pag mRNA and protective antigen protein than the parental strain harboring atxA in single copy on pXO1. These results indicate that increased AtxA expression does not lead to a corresponding increase in pag expression. Our data strongly suggest that an additional factor(s) is involved in regulation of pag and that the relative amounts of such a factor(s) and AtxA are important for optimal toxin gene expression.

The atxA gene product activates transcription of the anthrax toxin genes and is essential for virulence.

Bacillus anthracis plasmid pXO1 carries the structural genes for the three anthrax toxin proteins, cya (edema factor), lef (lethal factor), and pag (protective antigen). Expression of the toxin genes by B. anthracis is enhanced during growth under elevated levels of CO2. This CO2 effect is observed only in the presence of another pXO1 gene, atxA, which encodes a transactivator of anthrax toxin synthesis. Here we show that transcription of atxA does not appear to differ in cells grown in 5% CO2 compared with cells grown in air. Using a new efficient method for gene replacement in B. anthracis, we constructed an atxA-null mutant in which the atxA-coding sequence on pXO1 is replaced with an omega km-2 cassette. Transcription of all three toxin genes is decreased in the absence of atxA. The pag gene possesses two apparent transcription start sites, P1 and P2; only transcripts with 5' ends mapping to P1 are decreased in the atxA-null mutant. Deletion analysis of the pag promoter region indicates that the 111 bp region upstream of the P1 site is sufficient for atxA-mediated activation of this transcript. The cya and lef genes each have one apparent start site for transcription. Transcripts with 5' ends mapping to these sites are not detected in the atxA-null mutant. The atxA-null mutant is avirulent in mice. Moreover, the antibody response to all three toxin proteins is decreased significantly in atxA-null mutant-infected mice. These data suggest that the atxA gene product also regulates toxin gene expression during infection.

Regulation of the Bacillus anthracis protective antigen gene: CO2 and a trans-acting element activate transcription from one of two promoters.

The pag gene of Bacillus anthracis, located on plasmid pXO1 (185 kb), encodes protective antigen, a component of the anthrax lethal and edema toxins. Synthesis of protective antigen is enhanced during growth of the organism with elevated levels of CO2. The CO2 effect is at the level of transcription, and pXO1-encoded regulatory factors have been implicated in control of pag expression. We used a Tn917-LTV3 insertion mutant of B. anthracis in which the wild-type pag gene on pXO1 was replaced with a pag-lacZ transcriptional fusion to monitor pag promoter activity. Expression of the pag-lacZ fusion is induced five- to eightfold during growth in 5% CO2 compared with growth in air. Growth in 20% CO2 increases transcription up to 19-fold. By monitoring pag-lacZ expression in atmospheres with different O2 and CO2 concentrations, we demonstrated definitively that the CO2 effect is specific and not simply a result of increased anaerobiosis. The results of 5' end mapping of pag transcripts indicate multiple sites of transcript initiation. We have determined two major apparent start sites, designated P1 and P2, located at positions -58 and -26 relative to the translation initiation codon, respectively. Analysis of total RNA from late-log-phase cells shows comparable initiation from P1 and P2 in wild-type strains grown in aerobic conditions. However, initiation from P1 is increased approximately 10-fold in cultures grown with an elevated level (5%) of CO2. We have identified a locus on pXO1, more than 13 kb upstream from the pag gene, which enhances pag transcription. When added in trans, this locus increases the level of transcripts with 5' ends mapping to P1 but has no effect on the level of transcripts with 5' ends mapping to P2. The CO2 effect on P1 is observed only in the presence of the activator locus.

Psychophysiological reactions of patients with atopic dermatitis.

In a laboratory experiment, 20 female patients with atopic dermatitis (AD) and 20 female controls were exposed to two stress situations (watching a film about scarifications and tatooing, mental arithmetic). Recordings were made of systolic blood pressure, diastolic blood pressure, heart rate, skin conductance level (SCL), number of spontaneous (non-specific) electrodermal fluctuations (SF) and the PSI, the number of active palmar sweat glands in an area of the finger pad. Neither in the cardiovascular variables nor the PSI were any significant group differences found, neither for baseline nor stress values, nor for the response reactions. Atopic dermatitis persons had significantly lower values for SCL and SF throughout the whole experiment, although response reactions did not differ between groups. This study lends no support to the assumption of a general psychophysiological overreactivity or individual specific reactions of the skin system in patients with AD.

Frequency of migraine among an unselected group of employees and variation of prevalence according to different diagnostic criteria.

A survey was carried out among 940 employees in a mail administration building in Hamburg, Germany to determine the prevalence rates of headache and of migraine, based on several definitions. Headache symptoms were assessed by means of questionnaires, which were returned by 92% of the addressed persons and properly evaluable in 87.8%. When 3 out of the following 4 criteria a) occurrence of headaches in attacks b) unilaterality of pain c) preceding visual disturbances d) pulsating character were required to diagnose migraine, prevalence rate was low (5.3%). It rose dramatically when only 2 of these requirements had to be met (18.0%); based on the definition that 2 of a), b) or c) had to be fulfilled, the prevalence rates were 13.1% for females, 5.6% for males. There was no difference in frequency of migraine between the two large income classes of mail employees. In accordance with other studies we found that only 57.5% of migraine patients had ever consulted a doctor for their headache; only 13.7% had done so within the last half year.