Protein-altering variants of PTPN2 in childhood-onset Type 1A diabetes

AIM

To examine the contribution of PTPN2 coding variants to the risk of childhood-onset Type 1A diabetes.

METHODS

PTPN2 mutation analysis was carried out for 169 unrelated Japanese people with childhood-onset Type 1A diabetes. We searched for coding variants that were absent or extremely rare in the general population and were scored as damaging by multiple in silico programs. We performed mRNA analysis and three-dimensional structural prediction of the detected variants, when possible. We also examined possible physical links between these variants and previously reported risk SNPs as well as clinical information from variant-positive children.

RESULTS

One frameshift variant (p.Q286Yfs*24) and two probably damaging missense substitutions (p.C232W and p.R350Q) were identified in one child each. Of these, p.Q286Yfs*24 and p.C232W were hitherto unreported, while p.R350Q accounted for 2/121,122 alleles of the exome datasets. The p.Q286Yfs*24 variant did not encode stable mRNA, and p.C232W appeared to affect the structure of the tyrosine-protein phosphatase domain. The three variants were physically unrelated to known risk SNPs. The variant-positive children manifested Type 1A diabetes without additional clinical features and invariably carried risk human leukocyte antigen alleles.

CONCLUSIONS

The results provide the first indication that PTPN2 variants contribute to the risk of Type 1A diabetes, independently of known risk SNPs. PTPN2 coding variants possibly induce non-specific Type 1A diabetes phenotypes in individuals with human leukocyte antigen-mediated disease susceptibility. Our findings warrant further validation.

Next-generation sequencing for patients with non-obstructive azoospermia: implications for significant roles of monogenic/oligogenic mutations

Azoospermia affects up to 1% of adult men. Non-obstructive azoospermia is a multifactorial disorder whose molecular basis remains largely unknown. To date, mutations in several genes and multiple submicroscopic copy-number variations (CNVs) have been identified in patients with non-obstructive azoospermia. The aim of this study was to clarify the contribution of nucleotide substitutions in known causative genes and submicroscopic CNVs in the genome to the development of non-obstructive azoospermia. To this end, we conducted sequence analysis of 25 known disease-associated genes using next-generation sequencing and genome-wide copy-number analysis using array-based comparative genomic hybridization. We studied 40 Japanese patients with idiopathic non-obstructive azoospermia. Functional significance of molecular alterations was assessed by in silico analyses. As a result, we identified four putative pathogenic mutations, four rare polymorphisms possibly associated with disease risk, and four probable neutral variants in 10 patients. These sequence alterations included a heterozygous splice site mutation in SOHLH1 and a hemizygous missense substitution in TEX11, which have been reported as causes of non-obstructive azoospermia. Copy-number analysis detected five X chromosomal or autosomal CNVs of unknown clinical significance, in addition to one known pathogenic Y chromosomal microduplication. Five patients carried multiple molecular alterations. The results indicate that monogenic and oligogenic mutations, including those in SOHLH1 and TEX11, account for more than 10% of cases of idiopathic non-obstructive azoospermia. Furthermore, this study suggests possible contributions of substitutions in various genes as well as submicroscopic CNVs on the X chromosome and autosomes to non-obstructive azoospermia, which require further validation.

Development of a Broadband Telemedical Network Based on Internet Protocol in the Asia-Pacific Region

Objectives : To promote the exchange of knowledge and standardization of medical procedures and medical systems in the Asia-Pacific region, we established a medical networkwith high-quality moving images over broadband Internet lines in February 2003.

Methods : Real-time teleconferences and live demonstrations with medical-qualityvideos, broadcastvia the Digital Video Transport System, have been used t teach surgical techniques and other medical procedures across national borders.

The Asia-Pacific Advanced Network (APAN) committee in August 2005 formally approved our proposal to establish a medical working group within APAN. The networkwas expanded by the launch of the Trans- Eurasia Information Network 2 in 2006. By the end of 2006, we had conducted 82 events, in 10 countries in the Asia-Pacific region. The multi-station event has increased everyyear.

Results : There have been no serious transmission problems or ethical conflicts so far. With these experiences and current achievements, we hope to extend this advanced network system to the entire Asia-Pacific.

Conclusion : This system is a promising and very useful tool for the standardization of medical system and procedures across national borders. Drawing upon these experiences and current achievements, we hope to extend this advanced network system to the entire Asia- Pacific region.

Differentiation Effects by the Combination of Spheroid Formation and Sodium Butyrate Treatment in Human Hepatoblastoma Cell Line (Hep G2): A Possible Cell Source for Hybrid Artificial Liver

The aim of this study was to investigate the feasibility of human hepatoblastoma cell line (Hep G2), which differentiates by spheroid formation, and treatment with sodium butyrate (SB) as a cell source for hybrid artificial liver (HAL). Hep G2 spontaneously formed spheroids in polyurethane foam (PUF) within 3 days of culture and restored weak ammonia removal activity. Treatment with SB, which is a histone deacetylase inhibitor, further increased the ammonia removal activity of Hep G2 spheroids in a concentration-dependent manner. The activation of ornithine transcarbamylase—a urea cycle enzyme—was significantly related to the upregulation of ammonia removal by spheroid formation, but scarcely contributed to the further upregulation following SB treatment. In contrast with ammonia removal, treatment with SB reduced the albumin secretion of Hep G2 spheroids in a concentration-dependent manner. In the PUF-HAL module in a circulation culture, the ammonia removal rate and albumin secretion rate (per unit volume of the module) of Hep G2 spheroids treated with 5 mM SB were almost the same as those of primary porcine hepatocyte spheroids. These results suggest that simultaneous use of spheroid formation and SB treatment in Hep G2 is beneficial in enhancing the functions of human hepatocytes with potential applications in regenerative medicine and drug screening.

100 FACTORS AFFECTING PREGNANCY RATES IN THE TRANSFER OF IN VITRO-PRODUCED JAPANESE BLACK CATTLE EMBRYOS

Despite the rapid expansion of in vitro embryo production (IVP) technology for genetic improvement in the cattle industry in the last decades, pregnancy rates by the transfer of IVP embryos are still lower than those derived from in vivo-produced embryos. The objective of this study was to analyse factors affecting pregnancy rates after the transfer of IVP Japanese Black cattle embryos under farm conditions. Holstein heifers (n = 4,475) and cows (n = 8,541) were selected as recipients. Most cows (80%) were managed in tie-stall barns and most heifers (80%) were managed in pens. Embryo transfers were performed for 9 years, from 2004 to 2012. The embryos were produced from oocytes derived from a local abattoir and semen from 14 proven bulls by the Livestock Improvement Association of Japan (Hamano and Kuwayama 1993 Theriogelogy 39, 703–712). The fresh IVP embryos (quality; IETS code 1) that reached the blastocyst stage after 7 to 8 days (insemination = Day 0) were transported by an airplane (2 h) and subsequently by a car (1.5 h). Embryos were non-surgically transferred to each recipient on Day 7 to 9 of their natural oestrous cycle on farms. Pregnancy was diagnosed on Day 40 to 60 after oestrus. Pregnancy results were statistically analysed using the GLM procedures of SAS. The following variables were included in the model: recipient parity (0, 1, 2, or 3), day (7, 8, or 9) of the oestrous cycle at the time of embryo transfer, oestrus behaviour (increased activity observed by farmers), presence of mucus at oestrus, presence of blood after oestrus, and year (1, 2, 3, 4, 5, 6, 7, 8, or 9) and season (April–June as spring, July–September as summer, October–December as fall, or January–March as winter) of embryo transfer. The Bonferroni correction was used to counteract the problem of multiple comparisons. Heifers had significantly higher pregnancy rates than cows (51.0% v. 37.9%, respectively; P < 0.01), and first parity cows had higher pregnancy rates than third parity cows (42.9% v. 35.7%, respectively; P < 0.01). Pregnancy rates were significantly higher in recipients that received an embryo transfer on Day 8 of their oestrous cycle, than on Day 7 (46.6% v. 42.4%, respectively; P < 0.01). Recipients without oestrus behaviour had higher pregnancy rates than those with oestrus behaviour (46.3% v. 43.4%, respectively; P < 0.01). The presence of mucus and/or blood after oestrus and the season of transfer were not found to significantly affect pregnancy rates. The results of this study indicated that performing IVP embryo transfers on Day 8 of a recipient’s oestrous cycle will improve the pregnancy rate, season does not have an effect on pregnancy rate, and the detection of oestrus by monitoring increased activity is not always reliable and instead should be determined by multiple symptoms on farm conditions.

Roles of CLCA and CFTR in Electrolyte Re-absorption from Rat Saliva

A molecular basis for Cl− re-absorption has not been well-characterized in salivary ductal cells. Previously, we found strong expression of a rat homologue proposed to be Ca2+-dependent Cl− channels (rCLCA) in the intralobular ducts of the rat submandibular gland. To address the question as to whether rCLCA and cystic fibrosis transmembrane conductance regulator (CFTR) are involved in Cl− re-absorption, we evaluated the electrolyte content of saliva from glands pre-treated with a small interfering RNA (siRNA). Retrograde injection into a given submandibular duct of an siRNA designed to knock down either rCLCA or CFTR reduced the expression of each of the proteins. rCLCA and CFTR siRNAs significantly increased Cl− concentration in the final saliva during pilocarpine stimulation. These results represent the first in vivo evidence for a physiological significance of rCLCA, along with CFTR, in transepithelial Cl− transport in the ductal system of the rat submandibular gland.

The combined use of US and MR imaging for the diagnosis of masses in the parotid region

Purpose: To evaluate the usefulness of the combination of the two non-invasive modalities US and MR imaging to diagnose masses in the parotid region.

Material and Methods: The US and MR findings of 21 patients with parotid masses were analyzed retrospectively by two radiologists without any clinical or histopathological information. The specific points evaluated were location, shape, margin, internal architecture, and intensity level on both US and MR, posterior echo enhancement on US, and capsule-like lining of the tumor on MR.

Results: The findings concerning the shape and margin on US and MR were in fairly good agreement. Concerning the findings of the internal architecture, US could reveal the minute structures of the tumor while MR demonstrated differences in the signal intensities of histological tissue types of the various tumors. The posterior echo enhancement on US and the capsule-like lining on MR of the tumors were also useful for the diagnosis.

Conclusion: Our results suggest that the combination of US and MR is useful for examining soft tissue masses in the parotid region to make a more accurate diagnosis, and not just differentiate malignant lesions from those which are benign.

A clinical and ultrasonographic study of risk factors for elbow injury in young baseball players

PURPOSE

To determine the risk factors for elbow injury and its association with glenohumeral internal rotation deficit among young baseball players.

METHODS

229 baseball players aged 9 to 14 (mean, 11) years completed a self-administered questionnaire with items related to years of playing baseball, hours of training per weekday, days of training per week, and past and present experience of elbow pain. Two orthopaedic surgeons measured the range of motion of both shoulders and elbows. Another 2 orthopaedic surgeons performed ultrasonography to detect any elbow abnormality such as fragmentation of the medial epicondylar apophysis and osteochondritis dissecans of the capitellum. Using univariate and multivariable analyses, participants with or without elbow abnormality were compared to determine the risk factors for elbow abnormality.

RESULTS

Elbow abnormality was detected in 100 of the participants and comprised osteochondritis dissecans of the capitellum (n=18) and fragmentation of the medial epicondylar apophysis (n=82). Elbow abnormality was associated with being a pitcher, past and present experience of elbow pain, loss of elbow extension, and the side-to-side internal rotation difference. The 100 participants with elbow abnormality were stratified into symptomatic (n=57) or asymptomatic (n=43) of elbow pain. Those with elbow abnormality and elbow pain was associated with being a pitcher.

CONCLUSION

Being a pitcher was a risk factor for both elbow abnormality and elbow pain. Nonetheless, 43% of baseball players with elbow abnormality were asymptomatic. The use of ultrasonography was effective in detecting elbow abnormality and enabling early treatment.

Identification of a Hashimoto thyroiditis susceptibility locus via a genome-wide comparison with Graves' disease

BACKGROUND

Hashimoto thyroiditis (HT) and Graves' disease (GD) share some immunological features. Determining the genetic basis that distinguishes HT from GD is key for a better understanding of the differences between these two related diseases.

AIM

The aim of this study was to identify a non-HLA susceptibility locus that is specific to either HT or GD.

DESIGN

We performed a two-stage genome-wide comparison between HT and GD in Japan. During the discovery stage, we performed a logistic regression analysis adjusting for sex using 727 413 single nucleotide polymorphisms (SNPs) for 265 HT and 261 GD patients. During the replication stage, 35 SNPs were analyzed for 181 HT and 286 GD cases. A combined meta-analysis was performed using the results from these two stages. An SNP showing a genome-wide significant level was further analyzed using 1363 healthy controls to determine the specificity of susceptibility.

RESULTS

A genome-wide direct comparison between HT and GD revealed an SNP at the VAV3 locus with genome-wide significant association signals (rs7537605: P(combined) = 3.90 × 10(-8); odds ratio(combined) = 1.77; 95% confidence interval = 1.44-2.17). An association analysis using healthy controls showed that rs7537605 is significantly associated with HT (P = 1.24 × 10(-5); odds ratio = 1.60; 95% confidence interval = 1.30-1.97) but not with GD (P = .50), suggesting that the variant specifically affects susceptibility to HT.

CONCLUSION

A genome-wide direct comparison between HT and GD revealed an HT-specific variant within VAV3 in the Japanese. Considering physiological roles of VAV3, such as a guanine nucleotide exchange factor, our finding provides new insight into the molecular mechanism of HT.

Importance of specific reference values for evaluation of the deteriorating thyroid function in patients with end-stage renal disease on hemodialysis

BACKGROUND/AIM

We evaluated the thyroid function in end-stage renal disease (ESRD) on maintenance hemodialysis.

MATERIAL/METHODS

Thyroid function and clinical hypothyroid score were evaluated in 145 ESRD patients.

RESULTS

Comparison of thyroid function between 127 ESRD patients, excluding 18 patients with suppressed or elevated serum TSH level, and age/sex-matched healthy controls (76 in midlife group aged under 65 and 51 in late-life group aged 65 or over) using a multivariate logistic regression analysis suggested significant difference (P < 0.0001), mainly in serum fT4 level (P = 0.0099) and age (P = 0.0492), but not in serum fT3 (not significant; ns), TSH (ns) level or fT3/fT4 ratio (ns). Serum fT3 level and fT3/fT4 ratio were significantly lower (P < 0.001) in late-life group only in ESRD. Reference values calculated for midlife ESRD patients, such as 0.6-1.3 ng/dl for fT4 compared with 0.8-1.7 ng/dl for healthy control, were helpful for the diagnosis of mild but definite hyperthyroidism in whom serum fT4 level was 1.5 ng/dl. The prevalence of primary thyroid dysfunction, compared with the values for ESRD, was 0.7 % for hyperthyroidism, 1.4 % for overt hypothyroidism and 10.3 % for subclinical hypothyroidism. Hypothyroid score was high among those with ESRD independent of thyroid dysfunction.

CONCLUSIONS

Serum fT4 level was markedly lower without a change in fT3/fT4 ratio in ESRD. This may suggest typical carbohydrate-sufficient non-thyroidal illness. The specific reference values for ESRD were useful to evaluate borderline thyroid dysfunction and to evaluate the prevalence of the patients with primary thyroid dysfunction in ESRD.

Onset of reversible flaccid quadriplegia during treatment of thyrotoxic crisis

Two unrelated women were hospitalized for thyrotoxic crisis complicated by multiple organ failure. Both patients were treated with antithyroid drugs and hydrocortisone, as well as insulin for hyperglycemia, and underwent mechanical ventilation with sedation. Flaccid quadriplegia became apparent after each patient completely recovered their level of consciousness once sedation was discontinued on days 6 and 15, respectively. Three to six months of rehabilitation was required for the muscle strength to fully improve in both cases. Thyrotoxicosis in addition to critical illness polyneuromyopathy and the administration of glucocorticoid therapy may have contributed to the onset of quadriplegia in these two cases. Flaccid quadriplegia is one of the serious neuromuscular conditions experienced during the treatment of thyrotoxic crisis.

Remission after potassium iodide therapy in patients with Graves' hyperthyroidism exhibiting thionamide-associated side effects

CONTEXT

Thionamides have various side effects.

OBJECTIVE

The effectiveness of potassium iodide (KI) was evaluated in hyperthyroid patients who experienced side effects to thionamides.

DESIGN AND SETTING

An observational study was conducted at an academic medical center.

PATIENTS

Among 1388 patients with Graves' hyperthyroidism treated with thionamides, 204 (14.7%) exhibited side effects, and 44 were treated with KI and followed for 17.6 (median; range, 8.6-28.4) years.

MAIN OUTCOME MEASURES

The primary endpoint was the initial response to KI, and the secondary endpoint was the long-term prognosis.

RESULTS

The conditions of 29 (65.9%) of the 44 patients were well controlled with KI alone (10-400 mg/d) (A group), and 17 (38.6%) patients went into remission after 7.4 (1.9-23.0) years. The conditions of 15 (34.1%) patients were not controlled with KI alone (B group), even at a high dose (100-750 mg/d), but seven patients (15.9%) were controlled with a combination of KI and low-dose thionamides, resulting in remission after 7.2 (2.8-10.8) years. The initial parameters did not predict the response to KI or long-term prognosis. However, remission occurred in 70.8% of the patients treated with less than 200 mg of KI, compared with 35.0% of the patients who required 200 mg or more of KI (P < .05).

CONCLUSIONS

Among hyperthyroid patients with thionamide-associated side effects, KI therapy was effective in two-thirds of cases, and about 40% of the patients experienced remission after KI therapy alone. The chance of remission was small among the patients refractory to KI.

Identification of independent susceptible and protective HLA alleles in Japanese autoimmune thyroid disease and their epistasis

BACKGROUND

Autoimmune thyroid disease (AITD) includes Graves disease (GD) and Hashimoto thyroiditis (HT), which partially share immunological features. Determining the genetic basis that distinguishes GD and HT is a key to understanding the differences between these 2 related diseases.

AIM

The aims of this study were to identify HLA antigens that can explain the immunopathological difference between GD and HT and to elucidate epistatic interactions between protective and susceptible HLA alleles, which can delineate the distinct function of HLA in AITD etiology.

DESIGN

We genotyped 991 patients with AITD (547 patients with GD and 444 patients with HT) and 481 control subjects at the HLA-A, HLA-C, HLA-B, DRB1, DQB1, and DPB1 loci. A direct comparison of HLA antigen frequencies between GD and HT was performed. We further analyzed an epistatic interaction between the susceptible and protective HLA alleles in the development of GD and HT.

RESULTS

We identified 4 and 2 susceptible HLA molecules primarily associated with GD and HT, respectively, HLA-B*35:01, HLA-B*46:01, HLA-DRB1*14:03, and HLA-DPB1*05:01 for GD and HLA-A*02:07 and HLA-DRB4 for HT. In a direct comparison between GD and HT, we identified GD-specific susceptible class II molecules, HLA-DP5 (HLA-DPB1*05:01; Pc = 1.0 × 10(-9)) and HLA-DR14 (HLA-DRB*14:03; Pc = .0018). In contrast, HLA components on 3 common haplotypes in Japanese showed significant protective effects against the development of GD and HT (HLA-A*24:02-C*12:02-B*52:01-DRB1*15:02-DQB1*06:01-DPB1*09:01 and HLA-A*24:02-C*07:02-B*07:02-DRB1*01:01-DQB1*05:01-DPB1*04:02 haplotypes for GD and HLA-A*33:03-C*14:03-B*44:03-DRB1*13:02-DQB1*06:04-DPB1*04:01 haplotype for GD and HT). Interestingly, the representative protective HLA, HLA-DR13 (HLA-DRB1*13:02), was epistatic to susceptible HLA-DP5 in controlling the development of GD.

CONCLUSION

We show that HLA exerts a dual function, susceptibility and resistance, in controlling the development of GD and HT. We also show that the protective HLA allele is partially epistatic to the susceptible HLA allele in GD.