Evaluation of electron radiation damage to green fluorescent protein.

Green fluorescent protein (GFP) emits light when irradiated by not only light but also electrons. This electron-induced light emission called cathodoluminescence (CL) can be used to realize a high-resolution light emission microscopy based on the irradiation of a very narrow electron beam. To implement CL mapping in life sciences the investigation of the damage resistance of GFP to electron irradiation needs to be clarified. In this study, we investigated the electron radiation damage to GFP by analyzing the change in the CL intensity during electron beam irradiation. Since some of the CL spectra changed in shape during electron irradiation, the change in the intensity between 585 and 605 nm were measured. The characteristic doses at different electron current densities and electron energies were investigated. The characteristic dose of EGFP is much larger than that of coronene, which is one of the stable organic molecules against the electron beam irradiation.

The influence of compressive forces across the patellofemoral joint on patient-reported outcome after bi-cruciate stabilized total knee arthroplasty.

AIMS: Patellofemoral problems are a common complication of total knee arthroplasty. A high compressive force across the patellofemoral joint may affect patient-reported outcome. However, the relationship between patient-reported outcome and the intraoperative patellofemoral contact force has not been investigated. The purpose of this study was to determine whether or not a high intraoperative patellofemoral compressive force affects patient-reported outcome. PATIENTS AND METHODS: This prospective study included 42 patients (42 knees) with varus-type osteoarthritis who underwent a bi-cruciate stabilized total knee arthroplasty and in whom the planned alignment was confirmed on 3D CT. Of the 42 patients, 36 were women and six were men. Their mean age was 72.3 years (61 to 87) and their mean body mass index (BMI) was 24.4 kg/m 2 (18.2 to 34.3). After implantation of the femoral and tibial components, the compressive force across the patellofemoral joint was measured at 10°, 30°, 60°, 90°, 120°, and 140° of flexion using a load cell (Kyowa Electronic Instruments Co., Ltd., Tokyo, Japan) manufactured in the same shape as the patellar implant. Multiple regression analyses were conducted to investigate the relationship between intraoperative patellofemoral compressive force and patient-reported outcome two years after implantation. RESULTS: No patient had anterior knee pain after total knee arthroplasty. The compressive force across the patellofemoral joint at 140°of flexion was negatively correlated with patient satisfaction (R 2 = 0.458; ß = -0.706; p = 0. 041) and Forgotten Joint Score-12 (FJS-12; R 2 = .378; ß = -0.636; p = 0. 036). The compressive force across the patellofemoral joint at 60° of flexion was negatively correlated with the patella score (R 2 = 0.417; ß = -0.688; p = 0. 046). CONCLUSION: Patient satisfaction, FJS-12, and patella score were affected by the patellofemoral compressive force at 60° and 140° of flexion. Reduction of the patellofemoral compressive forces at 60° and 140° of flexion angle during total knee arthroplasty may improve patient-reported outcome, but has no effect on anterior knee pain.

Efficacy and safety of collagenase Clostridium histolyticum injection for Dupuytren's contracture in non-Caucasian Japanese patients (CORD-J Study): the first clinical trial in a non-Caucasian population.

To assess the efficacy, safety and pharmacokinetics of 0.58 mg collagenase Clostridium histolyticum injections for the treatment of Dupuytren's contracture in Japanese patients, we conducted a phase III, multicentre, uncontrolled, open-label clinical study in patients with Dupuytren's contracture. Of the 77 patients, 66 achieved clinical success in the primary treated joint (86%; 95% confidence interval: 76% to 93%), confirming the efficacy of collagenase Clostridium histolyticum injections. More improvement was seen in the metacarpophalangeal joints than in the proximal interphalangeal joints (94% versus 73%). The main adverse reaction was a local reaction in the injected hand. No tendon rupture or anaphylactic reactions were seen. The concentrations of collagenase Clostridium histolyticum were below the lower limit of quantification in plasma samples at all time points. As seen in global studies in Caucasian patients, a corrective effect on Dupuytren's contracture and good tolerance were observed in most non-Caucasian (Asian) Japanese patients. LEVEL OF EVIDENCE: Level 3.

Weekly injection of teriparatide for bone ingrowth after cementless total knee arthroplasty.

PURPOSE: To compare bone mineral density (BMD) in patients with or without weekly injection of teriparatide to promote bone ingrowth after cementless total knee arthroplasty (TKA). METHODS: Records of 8 men and 32 women (mean age, 75.6 years) who underwent cementless TKA for medial knee osteoarthritis with (n=20) or without (n=20) once-weekly subcutaneous/hypodermic injection of teriparatide for 48 weeks were reviewed. BMD and bone volume/total volume (BV/TV) of the bone-prosthesis interface of the proximal tibia in 6 regions of interest (ROI) were assessed at 3, 6, 9, and 12 months using multi-detector computed tomography. RESULTS: Patients with or without weekly injection of teriparatide after cementless TKA were comparable in terms of baseline characteristics and pre- and post-operative knee range of motion and Knee Society knee and function scores. In ROI 1 (medial), ROI 3 (anteromedial), and ROI 4 (posteromedial), the BV/TV increased throughout the postoperative period in patients with weekly injection of teriparatide and declined after 6 months in patients without weekly injection of teriparatide. These 3 ROIs of the 2 groups differed significantly only in BMD at 6, 9, and 12 months. In ROI 2 (lateral), ROI 5 (anterolateral), and ROI 6 (posterolateral), both BV/TV and BMD showed a decreasing trend, and these 3 ROIs of the 2 groups did not differ significantly. CONCLUSION: Weekly injection of teriparatide after cementless TKA promoted bone ingrowth mostly in the medial aspect of the bone-prosthesis interface.

Re-dislocation after corrective osteotomy for chronic dislocation of the radial head in children.

This retrospective study was designed to evaluate the outcomes of re-dislocation of the radial head after corrective osteotomy for chronic dislocation. A total of 12 children with a mean age of 11 years (5 to 16), with further dislocation of the radial head after corrective osteotomy of the forearm, were followed for a mean of five years (2 to 10). Re-operations were performed for radial head re-dislocation in six children, while the other six did not undergo re-operation ('non-re-operation group'). The active range of movement (ROM) of their elbows was evaluated before and after the first operation, and at the most recent follow-up. In the re-operation group, there were significant decreases in extension, pronation, and supination when comparing the ROM following the corrective osteotomy and following re-operation (p < 0.05). The children who had not undergone re-operation achieved a better ROM than those who had undergone re-operation. There was a significant difference in mean pronation (76° vs 0°) between the non- re-operation and the re-operation group (p = 0.002), and a trend towards increases in mean flexion (133° vs 111°), extension (0° vs 23°), and supination (62° vs 29°). We did not find a clear benefit for re-operation in children with a re-dislocation following corrective osteotomy for chronic dislocation of the radial head.

Low programmed cell death-1 (PD-1) expression in peripheral CD4(+) T cells in Japanese patients with autoimmune type 1 diabetes.

Programmed cell death-1 (PD-1) is a co-stimulatory molecule that inhibits T cell proliferation. We aimed to clarify PD-1 expression in CD4(+) T cells and the association between PD-1 expression and the 7785C/T polymorphism of PDCD1, with a focus on the two subtypes of type 1 diabetes, type 1A diabetes (T1AD) and fulminant type 1 diabetes (FT1D), in the Japanese population. We examined 22 patients with T1AD, 15 with FT1D, 19 with type 2 diabetes (T2D) and 29 healthy control (HC) subjects. Fluorescence-activated cell sorting (FACS) and real-time PCR were utilized to analyse PD-1 expression quantitatively. Genotyping of 7785C/T in PDCD1 was performed using the TaqMan method in a total of 63 subjects (21 with T1AD, 15 with FT1D and 27 HC). FACS revealed a significant reduction in PD-1 expression in CD4(+) T cells in patients with T1AD (mean: 4.2 vs. 6.0% in FT1D, P=0.0450; vs. 5.8% in T2D, P=0.0098; vs. 6.0% in HC, P=0.0018). PD-1 mRNA expression in CD4(+) T cells was also significantly lower in patients with T1AD than in the HC subjects. Of the 63 subjects, PD-1 expression was significantly lower in individuals with the 7785C/C genotype than in those with the C/T and T/T genotypes (mean: 4.1 vs. 5.9%, P=0.0016). Our results indicate that lower PD-1 expression in CD4(+) T-cells might contribute to the development of T1AD through T cell activation.

Chiral symmetry breaking in superfluid 3He-A.

Spontaneous symmetry breaking is an important concept in many branches of physics. In helium-3 ((3)He), the breaking of symmetry leads to the orbital chirality in the superfluid phase known as (3)He-A. Chirality is a fundamental property of (3)He-A, but its direct detection has been challenging. We report direct detection of chirality by transport measurements of electrons trapped below a free surface of (3)He-A. In particular, we observed the so-called intrinsic Magnus force experienced by a moving electron; the direction of the force directly reflected the chirality. We further showed that, at the superfluid transition, the system selected either right- or left-handed chirality. The observation of such selection directly demonstrates chiral symmetry breaking.

Association of genetic variation in FTO with risk of obesity and type 2 diabetes with data from 96,551 East and South Asians.

AIMS/HYPOTHESIS: FTO harbours the strongest known obesity-susceptibility locus in Europeans. While there is growing evidence for a role for FTO in obesity risk in Asians, its association with type 2 diabetes, independently of BMI, remains inconsistent. To test whether there is an association of the FTO locus with obesity and type 2 diabetes, we conducted a meta-analysis of 32 populations including 96,551 East and South Asians. METHODS: All studies published on the association between FTO-rs9939609 (or proxy [r (2) > 0.98]) and BMI, obesity or type 2 diabetes in East or South Asians were invited. Each study group analysed their data according to a standardised analysis plan. Association with type 2 diabetes was also adjusted for BMI. Random-effects meta-analyses were performed to pool all effect sizes. RESULTS: The FTO-rs9939609 minor allele increased risk of obesity by 1.25-fold/allele (p = 9.0 × 10(-19)), overweight by 1.13-fold/allele (p = 1.0 × 10(-11)) and type 2 diabetes by 1.15-fold/allele (p = 5.5 × 10(-8)). The association with type 2 diabetes was attenuated after adjustment for BMI (OR 1.10-fold/allele, p = 6.6 × 10(-5)). The FTO-rs9939609 minor allele increased BMI by 0.26 kg/m(2) per allele (p = 2.8 × 10(-17)), WHR by 0.003/allele (p = 1.2 × 10(-6)), and body fat percentage by 0.31%/allele (p = 0.0005). Associations were similar using dominant models. While the minor allele is less common in East Asians (12-20%) than South Asians (30-33%), the effect of FTO variation on obesity-related traits and type 2 diabetes was similar in the two populations. CONCLUSIONS/INTERPRETATION: FTO is associated with increased risk of obesity and type 2 diabetes, with effect sizes similar in East and South Asians and similar to those observed in Europeans. Furthermore, FTO is also associated with type 2 diabetes independently of BMI.

Avulsion of flexor digitorum profundus secondary to recurrent enchondroma.

We report a case of avulsion of the flexor digitorum profundus secondary to recurrent enchondroma. The tumor was curetted with bone grafting of cancellous bone from the distal radius, and the fragment avulsed by the flexor digitorum profundus tendon was fixed to its original site using a pullout suture through the distal phalanx to the nail. The lesion healed and function recovered 6 years after surgery.

Association of genetic variants for susceptibility to obesity with type 2 diabetes in Japanese individuals.

AIMS/HYPOTHESIS: In populations of East Asian descent, we performed a replication study of loci previously identified in populations of European descent as being associated with obesity measures such as BMI and type 2 diabetes. METHODS: We genotyped 14 single nucleotide polymorphisms (SNPs) from 13 candidate loci that had previously been identified by genome-wide association meta-analyses for obesity measures in Europeans. Genotyping was done in 18,264 participants from two general Japanese populations. For SNPs showing an obesity association in Japanese individuals, we further examined diabetes associations in up to 6,781 cases and 7,307 controls from a subset of the original, as well as from additional populations. RESULTS: Significant obesity associations (p < 0.1 two-tailed, concordant direction with previous reports) were replicated for 11 SNPs from the following ten loci in Japanese participants: SEC16B, TMEM18, GNPDA2, BDNF, MTCH2, BCDIN3D-FAIM2, SH2B1-ATP2A1, FTO, MC4R and KCTD15. The strongest effect was observed at TMEM18 rs4854344 (p = 7.1 × 10(-7) for BMI). Among the 11 SNPs showing significant obesity association, six were also associated with diabetes (OR 1.05-1.17; p = 0.04-2.4 × 10(-7)) after adjustment for BMI in the Japanese. When meta-analysed with data from the previous reports, the BMI-adjusted diabetes association was found to be highly significant for the FTO locus in East Asians (OR 1.13; 95% CI 1.09-1.18; p = 7.8 × 10(-10)) with substantial inter-ethnic heterogeneity (p = 0.003). CONCLUSIONS/INTERPRETATION: We confirmed that ten candidate loci are associated with obesity measures in the general Japanese populations. Six (of ten) loci exert diabetogenic effects in the Japanese, although relatively modest in size, and independently of increased adiposity.

Surgical treatment of spontaneous posterior interosseous nerve palsy: a retrospective study of 50 cases.

We have reviewed 38 surgically treated cases of spontaneous posterior interosseous nerve palsy in 38 patients with a mean age of 43 years (13 to 68) in order to identify clinical factors associated with its prognosis. Interfascicular neurolysis was performed at a mean of 13 months (1 to 187) after the onset of symptoms. The mean follow-up was 21 months (5.5 to 221). Medical Research Council muscle power of more than grade 4 was considered to be a good result. A further 12 cases in ten patients were treated conservatively and assessed similarly. Of the 30 cases treated surgically with available outcome data, the result of interfascicular neurolysis was significantly better in patients < 50 years old (younger group (18 nerves); good: 13 nerves (72%), poor: five nerves (28%)) than in cases > 50 years old (older group (12 nerves); good: one nerve (8%), poor: 11 nerves (92%)) (p < 0.001). A pre-operative period of less than seven months was also associated with a good result in the younger group (p = 0.01). The older group had a poor result regardless of the pre-operative delay. Our recommended therapeutic approach therefore is to perform interfascicular neurolysis if the patient is < 50 years of age, and the pre-operative delay is < seven months. If the patient is > 50 years of age with no sign of recovery for seven months, or in the younger group with a pre-operative delay of more than a year, we advise interfascicular neurolysis together with tendon transfer as the primary surgical procedure.

Costo-osteochondral graft for post-traumatic osteonecrosis of the radial head in an adolescent boy.

We present a case of post-traumatic osteonecrosis of the radial head in a 13-year-old boy which was treated with costo-osteochondral grafts. A satisfactory outcome was seen at a follow-up of two years and ten months. Although costo-osteochondral grafting has been used in the treatment of defects in articular cartilage, especially in the hand and the elbow, the extension of the technique to manage post-traumatic osteonecrosis of the radial head in a child has not previously been reported in the English language literature. Complete relief of pain was obtained and an improvement in the range of movement was observed. The long-term results remain uncertain.

Direct evidence for susceptibility genes for type 2 diabetes on mouse chromosomes 11 and 14.

AIMS/HYPOTHESIS: Diabetogenic loci for type 2 diabetes have been mapped to mouse chromosome (Chr) 11 and 14 in the Nagoya-Shibata-Yasuda (NSY) mouse, an animal model of type 2 diabetes. We aimed to obtain direct evidence of these genes on each chromosome and to clarify their function and interaction in conferring susceptibility to type 2 diabetes. METHODS: We established three consomic strains homozygous for diabetogenic NSY-Chr11, NSY-Chr14 or both on the control C3H background (C3H-11(NSY), C3H-14(NSY) and C3H-11(NSY)14(NSY), respectively), and monitored diabetes-related phenotypes longitudinally. The glucokinase gene was sequenced as a positional candidate gene on Chr11. RESULTS: C3H-11(NSY) mice showed hyperglycaemia associated with impaired insulin secretion and age-dependent insulin resistance without obesity. C3H-14(NSY) mice exhibited hyperglycaemia mainly due to insulin resistance, with a slight increase in percentage body fat. C3H-11(NSY)14(NSY) double consomic mice showed marked hyperglycaemia and obesity, which was not observed in single consomic strains. Sequences of the glucokinase gene were allelically variant between NSY and C3H mice. CONCLUSIONS/INTERPRETATION: These data provide direct evidence that Chr11 and Chr14 harbour major susceptibility genes for type 2 diabetes. These two chromosomes interact to cause more severe hyperglycaemia and obesity, which was not observed with the presence of either single chromosome, indicating different modes of gene-gene interaction depending on the phenotype. Marked changes in the phenotypes retained in the consomic strains will facilitate fine mapping and the identification of the responsible genes and their interaction with each other, other genes and environmental factors.

Common variants at the GCK, GCKR, G6PC2-ABCB11 and MTNR1B loci are associated with fasting glucose in two Asian populations.

AIMS/HYPOTHESIS: To test fasting glucose association at four loci recently identified or verified by genome-wide association (GWA) studies of European populations, we performed a replication study in two Asian populations. METHODS: We genotyped five common variants previously reported in Europeans: rs1799884 (GCK), rs780094 (GCKR), rs560887 (G6PC2-ABCB11) and both rs1387153 and rs10830963 (MTNR1B) in the general Japanese (n = 4,813) and Sri Lankan (n = 2,319) populations. To identify novel variants, we further examined genetic associations near each locus by using GWA scan data on 776 non-diabetic Japanese samples. RESULTS: Fasting glucose association was replicated for the five single nucleotide polymorphisms (SNPs) at p < 0.05 (one-tailed test) in South Asians (Sri Lankan) as well as in East Asians (Japanese). In fine-mapping by GWA scan data, we identified in the G6PC2-ABCB11 region a novel SNP, rs3755157, with significant association in Japanese (p = 2.6 x 10(-8)) and Sri Lankan (p = 0.001) populations. The strength of association was more prominent at rs3755157 than that of the original SNP rs560887, with allelic heterogeneity detected between the SNPs. On analysing the cumulative effect of associated SNPs, we found the per-allele gradients (beta = 0.055 and 0.069 mmol/l in Japanese and Sri Lankans, respectively) to be almost equivalent to those reported in Europeans. CONCLUSIONS/INTERPRETATION: Fasting glucose association at four tested loci was proven to be replicable across ethnic groups. Despite this overall consistency, ethnic diversity in the pattern and strength of linkage disequilibrium certainly exists and can help to appreciably reduce potential causal variants after GWA studies.

Differential association of HLA with three subtypes of type 1 diabetes: fulminant, slowly progressive and acute-onset.

AIM/HYPOTHESIS: We sought to clarify similarities and differences in the contribution of HLA to genetic susceptibility to three subtypes of type 1 diabetes: acute-onset, fulminant and slowly progressive. METHODS: We genotyped 545 Japanese patients with type 1 diabetes (338 acute-onset, 80 fulminant, 127 slowly progressive) and 396 control participants at HLA-DRB1, -DQB1, -A, -B and -C, and at 101 candidate single nucleotide polymorphisms (SNPs) in an 8.5 Mb region of the extended HLA. RESULTS: DRB1*0405-DQB1*0401, DRB1*0802-DQB1*0302 and DRB1*0901-DQB1*0303 were associated with acute-onset type 1 diabetes, with the DRB1*0405-DQB1*0401/DRB1*0802-DQB1*0302 genotype achieving the highest odds ratio of 42.7. DRB1*1501-DQB1*0602 and DRB1*1502-DQB1*0601 were negatively associated with acute-onset type 1 diabetes. A similar tendency was observed for slowly progressive type 1 diabetes. In contrast, only DRB1*0405-DQB1*0401 was associated with fulminant type 1 diabetes, with the DRB1*0405-DQB1*0401/DRB1*0405-DQB1*0401 genotype showing the highest odds ratio of 11.2. DRB1*0802-DQB1*0302, DRB1*0405-DQB1*0401/DRB1*0802-DQB1*0302 and DRB1*1501-DQB1*0602 were not associated with fulminant type 1 diabetes. The association of class I alleles and a panel of SNPs in an extended HLA region with fulminant type 1 diabetes was also different from that seen for the acute-onset and slowly progressive forms. The presence of both one and two susceptible haplotypes conferred susceptibility to slowly progressive type 1 diabetes, whereas the presence of two susceptible haplotypes was required to confer susceptibility to acute-onset and fulminant type 1 diabetes. CONCLUSIONS/INTERPRETATION: These data suggest that HLA associations with fulminant type 1 diabetes are qualitatively different from those with other subtypes of type 1 diabetes, whereas the HLA contribution to slowly progressive type 1 diabetes is qualitatively similar to, but quantitatively different from, that in acute-onset type 1 diabetes.

Isolated dorsal fracture-dislocation of the scaphoid: a case report.

This paper reports an isolated dorsal fracture-dislocation of the scaphoid at its waist with the proximal fragment dislocated dorsally. Such a fracture-dislocation is extremely rare. We believe the pathomechanics of this injury to have been a flexion and radial deviation with an axial force on the wrist.

Relative predispositional effects of HLA class II DRB1-DQB1 haplotypes and genotypes on type 1 diabetes: a meta-analysis.

The direct involvement of the human leukocyte antigen class II DR-DQ genes in type 1 diabetes (T1D) is well established, and these genes display a complex hierarchy of risk effects at the genotype and haplotype levels. We investigated, using data from 38 studies, whether the DR-DQ haplotypes and genotypes show the same relative predispositional effects across populations and ethnic groups. Significant differences in risk within a population were considered, as well as comparisons across populations using the patient/control (P/C) ratio. Within a population, the ratio of the P/C ratios for two different genotypes or haplotypes is a function only of the absolute penetrance values, allowing ranking of risk effects. Categories of consistent predisposing, intermediate ('neutral'), and protective haplotypes were identified and found to correlate with disease prevalence and the marked ethnic differences in DRB1-DQB1 frequencies. Specific effects were identified, for example for predisposing haplotypes, there was a statistically significant and consistent hierarchy for DR4 DQB1*0302s: DRB1*0405 =*0401 =*0402 > *0404 > *0403, with DRB1*0301 DQB1*0200 (DR3) being significantly less predisposing than DRB1*0402 and more than DRB1*0404. The predisposing DRB1*0401 DQB1*0302 haplotype was relatively increased compared with the protective haplotype DRB1*0401 DQB1*0301 in heterozygotes with DR3 compared with heterozygotes with DRB1*0101 DQB1*0501 (DR1). Our results show that meta-analyses and use of the P/C ratio and rankings thereof can be valuable in determining T1D risk factors at the haplotype and amino acid residue levels.

Fatty liver and obesity: phenotypically correlated but genetically distinct traits in a mouse model of type 2 diabetes.

AIMS/HYPOTHESIS: Obesity and fatty liver are commonly associated with type 2 diabetes, but the genetic and functional bases linking fatty liver with obesity and diabetes are largely unknown. Our aim was to investigate the association of fatty liver with obesity and other diabetes-related phenotypes and to define the genetic control of obesity and fatty liver. MATERIALS AND METHODS: We established 306 F2 mice by crossing Nagoya-Shibata-Yasuda (NSY) mice, an animal model of type 2 diabetes, with control C3H mice, and analysed their phenotypes. Whole-genome screening of F2 mice was performed to identify the loci responsible for fatty liver and obesity. RESULTS: A strong association of fatty liver with obesity, hyperinsulinaemia and hyperglycaemia was observed in F2 mice. Using whole-genome screening in 306 F2 mice, we mapped a new locus for fatty liver (Fl1n) on chromosome 6 (maximum logarithm of odds score [MLS] 10.0) and one for body weight (Bw1n) on chromosome 7 (MLS 5.1). Fl1n was linked to epididymal fat weight as well as fatty liver, but its effects were opposite in the two tissues in that the NSY allele increased liver fat but decreased epididymal fat, suggesting a role of Fl1n in partitioning of fat mass. The sequence of peroxisome proliferator-activated receptor gamma (Pparg), a candidate for Fl1n, showed allelic variation between NSY and C3H mice. CONCLUSIONS/INTERPRETATION: These data suggest that fatty liver and obesity are phenotypically related but genetically independent. Loci homologous to Fl1n and Bw1n are good candidate genes for susceptibility to fatty liver and obesity in humans.

Major quantitative trait locus on chromosome 2 for glucose tolerance in diabetic SMXA-5 mouse established from non-diabetic SM/J and A/J strains.

AIMS/HYPOTHESIS: The SMXA-5 mouse is one of the SMXA recombinant inbred substrains established from the non-diabetic SM/J and A/J strains, and is a model for polygenic type 2 diabetes, characterised by moderately impaired glucose tolerance and hyperinsulinaemia. These diabetic traits are worsened by feeding a high-fat diet. The aim of this study was to dissect the diabetogenic loci in the A/J regions of the SMXA-5 genome that contribute to diabetes-related traits. MATERIALS AND METHODS: We analysed the quantitative trait loci (QTL) for diabetes-related traits and obesity in (SM/JxSMXA-5)F(2) intercross mice fed a high-fat diet. To verify the function of the responsible locus that was mapped in the present study, we constructed a congenic strain and characterised its diabetes-related traits. RESULTS: A major QTL for glucose tolerance, free-fed blood glucose concentration and BMI was mapped on chromosome 2. This locus existed near D2Mit15, with the highest logarithm of the odds score (12.6) for glucose concentration at 120 min in a glucose tolerance test, and was designated T2dm2sa. The diabetogenic allele of T2dm2sa originated in the A/J strain. SM.A-T2dm2sa, a congenic strain that introgressed the T2dm2sa region of A/J genome into SM/J, exhibited overt impaired glucose tolerance and hyperinsulinaemia. CONCLUSIONS/INTERPRETATION: The development of impaired glucose tolerance in SM.A-T2dm2sa mice confirmed the results of QTL analysis for diabetes-related traits in F(2) intercross mice. The present results suggest that there are latent diabetogenic loci in the genomes of non-diabetic A/J and SM/J mice, and that the coexistence of these loci, including T2dm2sa, causes impaired glucose tolerance in SMXA-5 and SM.A-T2dm2sa mice.