Congenital hyperinsulinism: Global and Japanese perspectives

Over the past 20 years, there has been remarkable progress in the diagnosis and treatment of congenital hyperinsulinism (CHI). These advances have been supported by the understanding of the molecular mechanism and the development of diagnostic modalities to identify the focal form of ATP‐sensitive potassium channel CHI. Many patients with diazoxide‐unresponsive focal CHI have been cured by partial pancreatectomy without developing postsurgical diabetes mellitus. Important novel findings on the genetic basis of the other forms of CHI have also been obtained, and several novel medical treatments have been explored. However, the management of patients with CHI is still far from ideal. First, state‐of‐the‐art treatment is not widely available worldwide. Second, it appears that the management strategy needs to be adjusted according to the patient's ethnic group. Third, optimal management of patients with the diazoxide‐unresponsive, diffuse form of CHI is still insufficient and requires further improvement. In this review, we describe the current landscape of this disorder, discuss the racial disparity of CHI using Japanese patients as an example, and briefly note unanswered questions and unmet needs that should be addressed in the near future.     

Preimplantation genetic diagnosis/screening by comprehensive molecular testing

Although embryo screening by preimplantation genetic diagnosis (PGD) has become the standard technique for the treatment of recurrent pregnancy loss in couples with a balanced gross chromosomal rearrangement, the implantation and pregnancy rates of PGD using conventional fluorescence in situ hybridization (FISH) remain suboptimal. Comprehensive molecular testing, such as array comparative genomic hybridization and next‐generation sequencing, can improve these rates, but amplification bias in the whole genome amplification method remains an obstacle to accurate diagnosis. Recent advances in amplification procedures combined with improvements in the microarray platform and analytical method have overcome the amplification bias, and the data accuracy of the comprehensive PGD method has reached the level of clinical laboratory testing. Currently, comprehensive PGD is also applied to recurrent pregnancy loss due to recurrent fetal aneuploidy or infertility with recurrent implantation failure, known as preimplantation genetic screening. However, there are still numerous problems to be solved, including misdiagnosis due to somatic mosaicism, cell cycle‐related background noise, and difficulty in diagnosis of polyploidy. The technology for comprehensive PGD also requires further improvement.     

Copper Biology in Health and Disease: The accumulation of copper in the brain of Down syndrome promotes oxidative stress: possible mechanism underlying cognitive impairment

Individuals with Down syndrome (DS), which is caused by triplication of human chromosome 21 (Hsa21), show numerous characteristic symptoms, such as intellectual disability, an impaired cognitive function, and accelerated aging-like phenotypes. Enhanced oxidative stress is assumed to be implicated as a mechanism underlying many of these symptoms of DS. Some genes coded in Hsa21, such as App, Sod1, and Ets2, are suggested as being involved in the exacerbation of oxidative stress. In addition, enhanced oxidative stress has been recently shown to be caused by dyshomeostasis of the redox-active bio-metal copper in the brain of a mouse model of DS. This review aims to summarize the current knowledge on enhanced oxidative stress in DS and suggest a possible molecular mechanism underlying the cognitive impairment of DS mediated by enhanced oxidative stress.     

In vivo studies on the effects of α1-adrenoceptor antagonists on pupil diameter and urethral tone in rabbits

α₁-Adrenoceptors mediate contraction of iris dilator smooth muscle and hence pupil dilatation. We compared the ability of i.v. bolus injections of alfuzosin, doxazosin, naftopidil, prazosin, tamsulosin and terazosin to antagonise phenylephrine-induced mydriasis relative to their potency for inhibiting phenylephrine-induced elevations of intraurethral pressure (IUP) in rabbits. Moreover, we compared the ability of these drugs to induce miosis in conscious rabbits in the absence of phenylephrine. All antagonists inhibited the effects of phenylephrine on pupil size and IUP, and the ratio of the respective ED₅₀ values was close to unity in all cases. The doses required to induce statistically significant miosis in the absence of phenylephrine were 30- to 100-fold higher than those inhibiting phenylephrine-induced mydriasis for all antagonists, except for naftopidil. Moreover, the miotic effects of all α₁-adrenoceptor antagonists were fully reversible within 8 h. We conclude that alfuzosin, doxazosin, naftopidil, prazosin, tamsulosin and terazosin inhibit phenylephrine-induced mydriasis in the same dose range as they inhibit elevations in IUP. Higher doses of all antagonists are required to induce miosis in the absence of an exogenous agonist, and such miosis is always reversible within hours.     

Two proliferation-related proteins, TYMS and PGK1, could be new cytotoxic T lymphocyte-directed tumor-associated antigens of HLA-A2+ colon cancer.

PURPOSE: The purpose of this work was to provide a scientific basis for specific immunotherapy of colon cancer. EXPERIMENTAL DESIGN: This study focused on identification of colon tumor-associated antigens and HLA-A2-restricted and tumor-reactive cytotoxic T lymphocytes (CTLs) generated from tumor-infiltrating lymphocytes of a colon cancer patient. A gene expression cloning method was used to identify genes coding for tumor antigens. Fifty-six peptides with HLA-A2-binding motifs encoded by these proteins were examined for their ability to induce HLA-A2-restricted and tumor-reactive CTLs. RESULTS: We identified the following three genes coding for proliferation-related proteins: thymidylate synthase (TYMS), which is involved in chemoresistance (5-fluorouracil); 5'-aminoimidazole-4-carboxamide-1-beta-d-ribonucleotide transfolmylase/inosinicase (AICRT/I); and phosphoglycerate kinase 1 (PKG1), which was secreted by tumor cells and involved in the angiogenic process. TYMS was preferentially expressed in tumor cells, whereas AICRT/I and PKG1 were equally expressed in both cancer cells and normal tissues at the mRNA level. Among 56 peptides with HLA-A2-binding motifs encoded by these proteins, 8 peptides were recognized by the CTLs, and 5 of 8 peptides were also recognized by the CTL precursors without ex vivo activation in the peripheral blood of colon cancer patients. Furthermore, four of them (one each from TYMS and PKG1 and two from AICRT/1) possessed the ability to induce HLA-A2-restricted and peptide-specific CTLs cytotoxic to colon tumor cells in peripheral blood mononuclear cells of colon cancer patients. CONCLUSIONS: TYMS and PGK1, as well as their epitope peptides, might be appropriate target molecules for specific immunotherapy of HLA-A2(+) colon cancer patients because of the positive role of TYMS and PGK1 in chemoresistance (5-fluorouracil) and angiogenesis of tumor cells, respectively.     

Ureteral catheter placement for prevention of ureteral injury during laparoscopic hysterectomy

AIM: Ureteral injury is among the most devastating complications of gynecologic surgery. Estimated incidence of ureteral injury during laparoscopic hysterectomy is 2.6-35 times (0.2-6.0%) that in abdominal hysterectomy. We investigated preoperative ureteral catheter (UC) placement as a way to prevent ureteral injury in laparoscopic hysterectomy. METHODS: Clinical records of 94 women who underwent laparoscopic hysterectomy between February 2006 and January 2007 in Yazaki Hospital, Kanagawa, Japan, were reviewed retrospectively. Thirty-four patients between February and June 2006 underwent the surgery without ureteral catheterization and 60 patients between July 2006 and January 2007 underwent surgery with ureteral catheterization. Clinical outcomes were statistically compared between the two groups. RESULTS: The average time required for catheter insertion was 9.35 min. The ureter in which the catheter was placed was visualized clearly. In one patient, whose left ureter was deviated by a massive myoma, catheter insertion was not possible. No complications arose from catheter placement except for minor complaints including low back pain, urinary discomfort, and transient hematuria. While one injury occurred in a patient without ureteral catheterization (1/34), no ureteral injury occurred in any patient with ureteral catheterization (0/60). Operative time, total blood loss, and hospital stay were not significantly different between the two groups. CONCLUSIONS: UC placement is simple, helping to prevent ureteral injury during laparoscopic hysterectomy and enhancing safety of this procedure.