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The human voice is produced by flow-induced self-sustained oscillation of the vocal fold lamina propria. The mechanical properties of vocal fold tissues are important for understanding phonation, including the time-dependent and transient changes in fundamental frequency (F(0)). Cyclic uniaxial tensile tests were conducted on a group of specimens of the vocal fold lamina propria, including the superficial layer (vocal fold cover) (5 male, 5 female) and the deeper layers (vocal ligament) (6 male, 6 female). Results showed that the vocal fold lamina propria, like many other soft tissues, exhibits both elastic and viscous behavior. Specifically, the transient mechanical responses of cyclic stress relaxation and creep were observed. A three-network constitutive model composed of a hyperelastic equilibrium network in parallel with two viscoplastic time-dependent networks proves effective in characterizing the cyclic stress relaxation and creep behavior. For male vocal folds at a stretch of 1.4, significantly higher peak stress was found in the vocal ligament than in the vocal fold cover. Also, the male vocal ligament was significantly stiffer than the female vocal ligament. Our findings may help explain the mechanisms of some widely observed transient phenomena in F(0) regulation during phonation, such as the global declination in F(0) during the production of declarative sentences, and local F(0) changes such as overshoot and undershoot.

The effects of thiazolidinediones on cardiac function are controversial in humans with type 2 diabetes (T2DM) and in animals. Given the high prevalence and prognostic relevance of diastolic myocardial dysfunction in T2DM, we tested the hypothesis that by reducing oxidative stress rosiglitazone, but not glimepiride, may improve diastolic function. This randomised cross-over study investigated 12 metformin-treated T2DM patients without cardiovascular disease before and after 16 weeks of additional therapy with rosiglitazone (8 mg daily) or glimepiride (3 mg daily). Systolic and diastolic myocardial velocity (E') were assessed with tissue Doppler. In spite of similar non-significant lowering of glycosylated haemoglobin (HbA1C), rosiglitazone, but not glimepiride, significantly improved E' (p=0.04), reduced malondialdehyde (p=0.028), lowered high-sensitivity C-reactive protein (hsCRP) (p=0.019), and increased adiponectin (p=0.002). For rosiglitazone, multivariate regression analysis revealed malondialdehyde reduction as an independent determinant of treatment-induced improvement in E'. The rosiglitazone-induced improvements of diastolic function and oxidative stress may be of prognostic relevance in choosing therapy for T2DM patients without overt heart disease.

Objective: This longitudinal study performed continuous evaluation of daily blood glucose level profiles in healthy normal-weight pregnant patients during various gestational age and determined normal levels., Study Design: Thirty-two healthy normal-weight pregnant women received a continuous glucose monitoring system (CGMS) device for periods of 72h in the 16th, 22nd, 30th and 36th weeks of gestational age and at 6 weeks after delivery. All observations took place in the outpatient clinic of the Charité hospital. The daily blood glucose level profiles obtained with the CGMS provided pre- and postprandial blood glucose levels and a mean glucose value for a 24-h period. Caloric intake was determined using detailed food logs. Additionally, a fetal biometry and an measurement of maternal weight were performed at each visit. The correlation was tested using Spearman's test., Results: The average age of the study subjects was 29.6+/-4.5. Average pre-pregnancy BMI was 22.4+/-2.5kg/m(2). The births occurred on average in the 40th week of pregnancy. Average caloric intake was 2223+/-356kcal. No significant changes in caloric intake were observed during the course of the study. The blood glucose levels showed a significant rise throughout the course of the pregnancy, going from 4.84+/-0.4mmol/l (87.2+/-7.2mg/dl) during the 30th week of pregnancy to 5.22+/-0.5mmol/l (94.0+/-9.0mg/dl) during the 36th week (p=0.002). Postpartum levels were 5.20+/-0.5mmol/l (93.7+/-9.0mg/dl) (p=0.51). Fasting blood glucose levels did not change during the course of the pregnancy. A noticeable aspect were the significantly increased fasting postpartum levels with 5.02+/-0.6mmol/l (90.4+/-10.8mg/dl) (p=0.00). Analysis of the postprandial glucose levels confirmed a rise from 5.30+/-0.6mmol/l (95.5+/-10.8mg/dl) in the 16th week to 6.14+/-0.7mmol/l (110.6+/-12.6mg/dl) in the fourth study phase (36th week), and a decrease after the birth to 5.59+/-0.6mmol/l (100.7+/-10.8mg/dl). These measurements were adapted to the gestational age., Conclusion: Continuous measured glucose levels rose during the pregnancy in healthy pregnant women in spite of normal pre-pregnancy metabolism and unchanged carbohydrate intake during gestation. These results suggest the necessity of gestational-age-dependent cut-off values.

Stresses and strains within the vocal fold tissue may play a critical role in voice fatigue, in tissue damage and resulting voice disorders, and in tissue healing. In this study, experiments were performed to determine mechanical fields on the superior surface of a self-oscillating physical model of the human vocal folds using a three-dimensional digital image correlation method. Digital images obtained using a high-speed camera together with a mirror system were used to measure displacement fields, from which strains, strain rates, and stresses on the superior surface of the model vocal folds were computed. The dependence of these variables on flow rate was established. A Hertzian impact model was used to estimate the contact pressure on the medial surface from superior surface strains. A tensile stress dominated state was observed on the superior surface, including during collision between the model folds. Collision between the model vocal folds limits the medial-lateral stress levels on the superior surface, in conjunction with compressive stress or contact pressure on the medial surface.

Experimental evidence demonstrates that collagen cross-linking in bone tissue significantly influences its deformation and failure behavior yet difficulties exist in determining the independent biomechanical effects of collagen cross-linking using in vitro and in vivo experiments. The aim of this study is to use a nano-scale composite material model of mineral and collagen to determine the independent roles of enzymatic and non-enzymatic cross-linking on the mechanical behavior of a mineralized collagen fibril. Stress-strain curves were obtained under tensile loading conditions without any collagen cross-links, with only enzymatic cross-links (modeled by cross-linking the end terminal position of each collagen domain), or with only non-enzymatic cross-links (modeled by random placement of cross-links within the collagen-collagen interfaces). Our results show enzymatic collagen cross-links have minimal effect on the predicted stress-strain curve and produce a ductile material that fails through debonding of the mineral-collagen interface. Conversely, non-enzymatic cross-links significantly alter the predicted stress-strain response by inhibiting collagen sliding. This inhibition leads to greater load transfer to the mineral, which minimally affects the predicted stress, increases modulus and decreases post-yield strain and toughness. As a consequence the toughness of bone that has more non-enzymatically mediated collagen cross-links will be drastically reduced.

Angiotensin-converting enzyme (ACE) inhibitors can improve cardiovascular outcome in patients with type 2 diabetes mellitus (T2DM). Myocardial diastolic function (Ve) is a known marker of cardiovascular prognosis. It could potentially indicate the effects of preventive therapy if evaluated by tissue Doppler. We tested the hypothesis that treatment with the ACE inhibitor ramipril has beneficial effects on Ve. In this study, 16 subjects on insulin therapy (eight receiving 10 mg ramipril/day compared to eight matched controls who were not treated with an ACE inhibitor) were followed up for a period of nine months. Myocardial and vascular function were assessed by tissue Doppler and ultrasound. In the ramipril group, Ve improved significantly after nine months of treatment (7.8+/-0.9 cm/s to 8.6+/-0.9 cm/s, p<0.04). Systolic blood pressure and intima media thickness (IMT) demonstrated a trend towards improvement. In controls, Ve remained unchanged and there was a trend towards deterioration in stiffness index beta (p<0.07). In conclusion, the observed improvement of myocardial diastolic function with ramipril in patients with T2DM is an encouraging result. It might contribute to the overall improvement that has been observed with hard cardiovascular end points.

The mechanical properties of the vocal fold lamina propria, including the vocal fold cover and the vocal ligament, play an important role in regulating the fundamental frequency of human phonation. This study examines the equilibrium hyperelastic tensile deformation behavior of cover and ligament specimens isolated from excised human larynges. Ogden's hyperelastic model is used to characterize the tensile stress-stretch behaviors at equilibrium. Several statistically significant differences in the mechanical response differentiating cover and ligament, as well as gender are found. Fundamental frequencies are predicted from a string model and a beam model, both accounting for the cover and the ligament. The beam model predicts nonzero F(0) for the unstretched state of the vocal fold. It is demonstrated that bending stiffness significantly contributes to the predicted F(0), with the ligament contributing to a higher F(0), especially in females. Despite the availability of only a small data set, the model predicts an age dependence of F(0) in males in agreement with experimental findings. Accounting for two mechanisms of fundamental frequency regulation--vocal fold posturing (stretching) and extended clamping--brings predicted F(0) close to the lower bound of the human phonatory range. Advantages and limitations of the current model are discussed.

Background: In patients with type 2 diabetes mellitus diastolic dysfunction is a frequent manifestation of myocardial disease with poor prognosis. The hypothesis that better glycemic control results in improved myocardial function was tested using tissue Doppler., Methods: During a short-term (3 weeks) and a long-term (52 weeks) study, metabolic control and myocardial function were evaluated in 33 and 50 patients, respectively, with type 2 diabetes. Systolic (Vs) and diastolic (Ve) myocardial velocity were assessed by tissue Doppler. In the short-term study, antidiabetic therapy was intensified in 25 patients (Int3) and compared to those eight individuals with unchanged therapy (Con3), similarly to the long-term study with Int52 (n = 39) and Con52 (n = 11)., Results: In Int3, fasting serum glucose was reduced by 69+/-47 mg/dl (p < 0.01) compared to baseline and was associated with an increase of Ve from 8.0 +/- 1.6 to 8.8 +/- 1.6 cm/s (p < 0.01) and Vs from 6.2 +/- 1.1 to 6.6 +/- 1.3 cm/s, p < 0.04. In Con3, serum glucose and myocardial velocities were unchanged. In Int52, fasting serum glucose was reduced by 20 +/- 43 mg/dl (p < 0.017) compared to baseline and was associated with an increase of Ve from 7.6 +/- 1.3 to 8.3 +/- 1.7 cm/s (p < 0.002) and a similar trend in Vs (p < 0.07). In Con52, serum glucose and myocardial velocities remained unchanged. Evaluating pooled data, the changes of diastolic myocardial velocity correlated significantly with the changes of serum glucose (r = 0.49, p < 0.004 short- and r = 0.45; p < 0.002 long-term study, respectively)., Conclusion: In patients with type 2 diabetes subclinical diastolic myocardial dysfunction, measured as diastolic myocardial velocity by tissue Doppler, improves with better glycemic control.

Aim of Study: The aim of the study was to find to find out which factors are able to predict the disease-specific knowledge of in-patient diabetic patients and to characterize this group of patients., Methods: The disease-specific knowledge of diabetic patients of a Hospital in Munich, Germany (department of diabetology) was tested using a general questionnaire and a specific diabetes knowledge test. All data manipulation and statistical calculations were conducted with the statistical software package SAS (version 9.1)., Results: On average type-1-diabetics achieved 73% of the possible points in the knowledge test, type-2-diabetics achieved 68% of total points. In bivariate analyses, using logistic regression, existence of diabetes related complications was a significant predictor of poor knowledge (OR = 4.36; 95%-KI: 1.38-13.77) in type-1-diabetics. Other factors, e. g. lack of diabetes education were associated with low test results but reached no statistical significance (OR = 6.13; 95%-KI: 0.67-56.42). In multivariate logistic regression (female) gender was a significant risk factor for low test results (OR = 7.66; 95%-KI: 1.18-49.8). In type-2-diabetics lack of diabetes education (OR = 3.86; 95%-KI: 1.51-9.84), low self-assessment of information about diabetes (OR = 3.90; 95%-KI: 1.36-11.21) and lack of knowledge about diabetes diet (OR = 4.06; 95%-KI: 1.60-10.28) were predictors of poor test results. The existence of diabetes related complications was associated with poor test results but showed no statistical significance in multivariate analysis (OR = 2.99; 95%-KI: 0.85-10.43)., Conclusions: There is a group of diabetic inward-patients that is less informed about diabetes and shows knowledge deficits in testing. These patients often lack diabetes education and show an unfavourable course of the disease, already having diabetes related complications. Type-2-diabetes patients who feel that they have poor information about their disease actually achieve lower results in knowledge testing. Efforts to assure diabetes education for these patients are essentially necessary.

The elastic as well as time-dependent mechanical response of the vocal fold cover (epithelium and superficial layer of the lamina propria) under tension is one key variable in regulating the fundamental frequency. This study examines the hyperelastic and time-dependent tensile deformation behavior of a group of human vocal fold cover specimens (six male and five female). The primary goal is to formulate a constitutive model that could describe empirical trends in speaking fundamental frequency with reasonable confidence. The constitutive model for the tissue mechanical behavior consists of a hyperelastic equilibrium network in parallel with an inelastic, time-dependent network and is combined with the ideal string model for phonation. Results showed that hyperelastic and time-dependent parameters of the constitutive model can be related to observed age-related and gender-related differences in speaking fundamental frequency. The implications of these findings on fundamental frequency regulation are described. Limitations of the current constitutive model are discussed.

This article reports the production of an EP-element insertion library with more than 3,700 unique target sites within the Drosophila melanogaster genome and its use to systematically identify genes that affect embryonic muscle pattern formation. We designed a UAS/GAL4 system to drive GAL4-responsive expression of the EP-targeted genes in developing apodeme cells to which migrating myotubes finally attach and in an intrasegmental pattern of cells that serve myotubes as a migration substrate on their way towards the apodemes. The results suggest that misexpression of more than 1.5% of the Drosophila genes can interfere with proper myotube guidance and/or muscle attachment. In addition to factors already known to participate in these processes, we identified a number of enzymes that participate in the synthesis or modification of protein carbohydrate side chains and in Ubiquitin modifications and/or the Ubiquitin-dependent degradation of proteins, suggesting that these processes are relevant for muscle pattern formation., Competing Interests: Competing interests. The authors have declared that no competing interests exist.

In human voice production (phonation), linear small-amplitude vocal fold oscillation occurs only under restricted conditions. Physiologically, phonation more often involves large-amplitude oscillation associated with tissue stresses and strains beyond their linear viscoelastic limits, particularly in the lamina propria extracellular matrix (ECM). This study reports some preliminary measurements of tissue deformation and failure response of the vocal fold ECM under large-strain shear The primary goal was to formulate and test a novel constitutive model for vocal fold tissue failure, based on a standard-linear cohesive-zone (SL-CZ) approach. Tissue specimens of the sheep vocal fold mucosa were subjected to torsional deformation in vitro, at constant strain rates corresponding to twist rates of 0.01, 0.1, and 1.0 rad/s. The vocal fold ECM demonstrated nonlinear stress-strain and rate-dependent failure response with a failure strain as low as 0.40 rad. A finite-element implementation of the SL-CZ model was capable of capturing the rate dependence in these preliminary data, demonstrating the model's potential for describing tissue failure. Further studies with additional tissue specimens and model improvements are needed to better understand vocal fold tissue failure.

Investigations within the framework of the thyroid gland initiative "Papillon" turned up an unexpectedly high level of pathogenic findings. Determination of TSH and sonography are considered the pillars of the diagnostic evaluation of the thyroid gland. Useful further investigations aimed at excluding functional disorders are, for example, the determination of FT3 and FT4 or a search for autoantibodies. To investigate suspicious nodules and to exclude malignant processes, additional scintigraphy and, were indicated, fine-needle puncture can be applied. Depending on the individual situation of the patient, the therapeutic option of choice is surgical operation or treatment with iodine-31 therapy. Medical treatment of nodular goiter is currently still controversial.

Background: Temporomandibular disorders are not an uncommon finding in adult patients undergoing orthodontic treatment., Patient and Methods: In a 25-year-old female patient with neutroclusion, bialveolar protrusion with anterior crowding, and mesial tipping of tooth 27 due to early loss of tooth 26, a unilateral clicking in the right temporomandibular joint was recorded as a secondary finding. Clinical and instrumental functional analysis revealed right-sided anterior disc displacement with reduction, which had been induced by forced guidance of the mandible to posterior. Space was to be gained by extracting tooth 41, by closing the residual gap at tooth 26, and by interproximal reduction of the dental enamel in the right upper buccal region. In addition, occlusal adjustment was to be undertaken subsequently to eliminate the forced guidance and to achieve a slightly overcorrected Class I relationship., Result: Treatment wit a complete fixed appliance fulfilled the treatment objectives, with normal functioning of the temporomandibular joint being achieved. This case of a patient with a temporomandibular disorder is used to illustrate steps in diagnosis and functional analysis. Steps which ensure not only a successful orthodontic outcome but also a beneficial orthopedic effect on the temporomandibular joint.

Many prokaryotic and eukaryotic DNA-binding proteins use a helix-turn-helix (HTH) structure for DNA recognition. Here we describe a new family of eukaryotic HTH proteins, the Pipsqueak (Psq) family, which includes proteins from fungi, sea urchins, nematodes, insects, and vertebrates. Three subgroups of the Psq family can be distinguished. Like the HTH proteins of the prokaryotic resolvase family, members of the CENP-B/transposase subgroup catalyze site-specific recombination reactions. This functional conservation, together with a primary sequence similarity between the resolvase and Psq DNA-binding domains, suggests that the resolvase and Psq families are evolutionarily linked. More than half of the newly identified Drosophila Psq proteins contain a BTB protein-protein interaction domain. All proteins of this BTB subgroup belong to the conserved Tramtrack group of BTB-domain proteins. About half of the members of the Tramtrack group contain a Psq domain, while the other half is made up of proteins that contain a zinc finger domain. Thus, nearly all members of this group appear to be DNA-binding proteins. Among other developmental regulators, the Drosophila cell death protein E93 was found to contain a Psq motif and to define a third subgroup of Psq domain proteins. The high sequence conservation of the E93 Psq motif allowed the identification of E93 orthologs in humans and lower metazoans.

In insects, peptidergic neurons of the central nervous system regulate the synthesis of the main developmental hormones. Neuropeptides involved in this neuroendocrine cascade have been identified in lepidopterans and dictyopterans. Since these organisms are not suitable for genetic research, we identified peptidergic brain neurons innervating the ring gland in Drosophila melanogaster. In larvae of Drosophila, ecdysteroids and juvenile hormones are produced by the ring gland, which is composed of the prothoracic gland, the corpus allatum, and the corpora cardiaca. Using the GAL4 enhancer trap system, we mapped those neurons of the central nervous system that innervate the ring gland. Eleven groups of neurosecretory neurons and their target tissues were identified. Five neurons of the lateral protocerebrum directly innervate the prothoracic gland or corpus allatum cells of the ring gland and are believed to regulate ecdysteroid and juvenile hormone titers. Axons of the circadian pacemaker neurons project onto dendritic fields of these five neurons. This connection might be the neuronal substrate of the circadian rhythms of molting and metamorphosis in Drosophila. Most of the neurons presented here have not been described before. The enhancer trap lines labeling them will be valuable tools for the analysis of neuronal as well as genetic regulation in insect development., (Copyright 2001 Wiley-Liss, Inc.)

Several studies have demonstrated an association of CTLA4 (IDDM12) alanine-17 with type 1 diabetes, but CTLA4 variants have not yet been investigated in type 2 diabetes. The CTLA4 exon 1 polymorphism (49 A/G) was analyzed in 300 Caucasian patients with type 2 diabetes and 466 healthy controls. All patients were negative for glutamate decarboxylase and islet cell antibodies. CTLA4 alleles were defined by PCR, single-strand conformational polymorphism, and restriction length fragment polymorphism analysis using BBV:I. The distribution of alleles as well as the genotypic and phenotypic frequencies were similar among patients and controls [AA, 42 vs. 39%; AG, 47 vs. 46%; GG, 11 vs. 15%, P = not significant (n.s.); A/G, 65/35% vs. 62/38%, P = n.s.; alanine/threonine 92/58% vs. 85/61%, P = n.s.]. However, detailed analysis of clinical and biochemical parameters revealed a tendency of GG (alanine/alanine) toward younger age at disease manifestation (46.8 +/- 0.8 vs. 49.5 +/- 0.8 yr, mean +/- SEM), lower body mass index (21.4 +/- 0.5 vs. 24.4 +/- 0.5 kg/m(2), P = 0.042), and basal C-peptide level (0.33 +/- 0.07 vs. 0.53 +/- 0.07nmol/L), as well as earlier start of insulin treatment (5.8 +/- 1.2 vs. 8.7 +/- 0.6 yr) and higher portion of patients on insulin (71 vs. 61%). Patients with the AA genotype were significantly less likely to develop microangiopathic lesions (P < 0.0005). No differences were found for hypertension or family history of type 2 diabetes. In conclusion, CTLA4 alanine-17 does not represent a major risk factor for type 2 diabetes. Additional studies on larger groups and different ethnic groups are warranted to clarify the association of the GG genotype with faster ss-cell failure and the lower rate of microvascular complications in AA carriers.

Previous analyses of NOD mice have shown that some genes control the development of both insulitis and diabetes, while other loci influence diabetes without reducing insulitis. Evidence for the existence of a gene only influencing diabetes, Idd9 on mouse chromosome 4, is provided here by the development of a novel congenic mouse strain, NOD.B10 Idd9. NOD.B10 Idd9 mice display profound resistance to diabetes even though nearly all develop insulitis. Subcongenic analysis has demonstrated that alleles of at least three B10 genes, Idd9.1, Idd9.2, and Idd9.3 are required to produce Idd9-mediated diabetes resistance. Candidate genes with amino acid differences between the NOD and B10 strains have been localized to the 5.6 cM Idd9.2 interval (Tnfr2, Cd30) and to the 2.0 cM Idd9.3 interval (Cd137).

Graves' disease is exceptional as a disorder of stimulatory autoimmunity in comparison with all other endocrine autoimmunopathies. Research into its pathogenesis has so far focussed on the genetics next to characterisation of antibody-antigen as well as T-lymphocyte interactions. A multigenic predisposition similar to other autoimmune diseases has been proposed. Such polygenic disorders are frequent in the population and require special genetic epidemiological tools to dissect the many gene loci, where polymorphisms are readily detectable by several molecular typing assays. This review presents these tools and methods as well as the currently identified main susceptibility loci in the Human Leukocyte Antigen (HLA DQA1*0501), cytotoxic T-lymphocyte antigen 4 (CTLA4-ala17) as well as interferon-gamma (IFN-gamma *2) regions. Most of these predisposing alleles are shared risk factors in several endocrine autoimmune diseases. Further research is required to identify those gene variants that determine the individual course of thyroid stimulation or destruction.

Major genetic susceptibility to type 1 diabetes mellitus maps to the human leukocyte antigen (HLA) region on chromosome 6p. During evolution, endogenous retroviral long terminal repeats (LTR) have been integrated at several sites within this region. We analyzed the presence of a solitary HERV-K LTR in the HLA DQ region (DQ-LTR3) and its linkage to DRB1, DQA1, and DQB1 haplotypes derived from 246 German and Belgian families with a patient suffering from type 1 diabetes mellitus. Segregation analysis of 984 HLA DQA1/B1 haplotypes showed that DQ-LTR3 is linked to distinct DQA1 and DQB1 haplotypes but is absent in others. The presence of DQ-LTR3 on HLA DQB1*0302 haplotypes was preferentially transmitted to patients from heterozygous parents (82%; P < 10(-6)), in contrast to only 2 of 7 DQB1*0302 haplotypes without DQ-LTR3. Also, the extended HLA DRB1*0401, DQB1*0302 DQ-LTR3-positive haplotypes were preferentially transmitted (84%; P < 10(-6)) compared with 1 of 6 DR-DQ matched DQ-LTR3 negative haplotypes. DQ-LTR3 is missing on most DQB1*0201 haplotypes, and those LTR3 negative haplotypes were also preferentially transmitted to patients (80%; P < 10(-6)), whereas DQB1*0201 DQ-LTR3-positive haplotypes were less often transmitted to patients (36%). Other DQA1/B1 haplotypes did not differ for DQ-LTR3 between transmitted and nontransmitted haplotypes. Thus, the presence of DQLTR3 on HLA DQB1*0302 and its absence on DQB1*0201 haplotypes are independent genetic risk markers for type 1 diabetes.

Cystic fibrosis (CF) is one of the most common recessively inherited disorders in Caucasian populations and is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. A three base deletion known as deltaF508 occurs on about 70%, of CF chromosomes and accounts for the high prevalence of the disease. Since type 2 diabetes mellitus occurs more frequently in relatives of patients with CF than in the normal population, we addressed the hypothesis whether heterozygosity for deltaF508 might be a genetic risk factor for type 2 diabetes. We screened 301 patients with type 2 diabetes mellitus which had been treated for at least three years from diagnosis by diet or oral antihyperglycemic agents. Healthy controls (n = 282) had no family history for diabetes. The genotype distribution did not differ significantly between patients with type 2 diabetes (2% heterozygotes) and controls (3% heterozygotes). According to these results, we conclude, that the deltaF508 mutation in its heterozygous form does not represent a major genetic risk factor for type 2 diabetes mellitus.

Although some of the susceptibility to Graves' disease is conferred by genes in the human leucocyte antigen (HLA) region on the short arm of chromosome 6, other genetic factors must also predispose. Among the cytokines involved in thyroid autoimmunity interferon-gamma (IFN-gamma) plays a key role in the pathogenesis of Graves' disease. We therefore analyzed the first intron of the IFN-gamma gene for a dinucleotide (CA) repeat polymorphism on chromosome 12q. Two hundred two Caucasian patients with Graves' disease and 214 Caucasian controls were analyzed by polymerase chain reaction (PCR) and subsequent polyacrylamide gel electrophoresis technique: eight different alleles designated as IFN-gamma*1 to IFN-gamma*8 could be differentiated. Among Graves' disease patients IFN-gamma*5 (12.9% vs. 6.8%, p < 0.04) was significantly more frequent whereas IFN-gamma*2 (2.5% vs. 9.8%, p < 0.002) was significantly less frequent. Patients positive for the genetic susceptibility marker HLA DQA1*0501 had significantly more IFN-gamma*3 alleles (13.6% vs. 2.6%, p < 0.009) and IFN-gamma*5 alleles (22.1% vs. 7.6%, p < 0.03) compared with DQA1*0501 positive controls. Also, among patients with endocrine ophthalmopathy IFN-gamma*3 (17.9% vs. 4.2%, p < 8 x 10(-6)) and IFN-gamma*5 (18.9% vs. 7.0%, p < 0.003) were significantly more frequent compared with controls. Although a significant association of IFN-gamma microsatellite polymorphism was observed, only a small proportion of Graves' disease patients have these markers. Thus, it is likely that the detected microsatellite polymorphisms play only a minor role in the susceptibility to Graves' disease.

The genetic susceptibility to Graves' disease and type 1 (insulin-dependent) diabetes mellitus is conferred by genes in the human leukocyte antigen region on the short arm of chromosome 6, but several other genes are presumed to determine disease susceptibility. Among those candidate genes is the cytotoxic T lymphocyte antigen 4 (CTLA4) located on chromosome 2q33 in man. We investigated the distribution of the CTLA4 exon 1 polymorphism (49 A/G) in Graves' disease and IDDM. This dimorphism at codon 17 results in an amino acid exchange (Thr/Ala) in the leader peptide of the expressed protein and was analyzed by PCR, single strand conformation polymorphism, and restriction fragment length polymorphism analysis in 305 patients with Graves' disease, 293 patients with IDDM, and 325 controls. Patients with Graves' disease had significantly more Ala alleles than controls, both as homozygotes (21% vs. 13%) and as heterozygotes (53% vs. 46%), and less Thr as homozygotes (26% vs. 42%; P < 2 x 10(-4). The phenotypic frequency of Ala-positive patients (73%) was significantly higher than of controls (58%; P = 10(-4); relative risk = 2). Patients with IDDM also had significantly more Ala alleles as homozygotes (19%) or heterozygotes (50%; P = 0.01). In conclusion, an alanine at codon 17 of CTLA4 is associated with genetic susceptibility to Graves' disease as well as to IDDM.