Laboratory investigation of microelectronics-based stimulators for large-scale suprachoroidal transretinal stimulation (STS).

This paper describes the technological developments underlying the realization of a reliable and reproducible microchip-based stimulator with a large number of stimulus electrodes. A microchip-based stimulator with over 500 electrodes for suprachoroidal transretinal stimulation (STS) is proposed in this paper, and an example is presented. To enhance reliability and reproducibility for such a large array, we introduce a flip-chip bonding technique and place microchips on the reverse side of a substrate. A square microchip of size 600 microm was fabricated using 0.35 microm standard CMOS process technology. Twelve microchips were flip-chip bonded on a polyimide substrate through Au bumps. To evaluate the feasibility of the proposed device, we successfully fabricated a stimulator with 12 microchips and 118 electrodes made of Pt/Au bumps, and demonstrated their operation in a saline solution for 2 weeks. Also, to evaluate the device operation in vivo, a stimulator with one active IrO(x) electrode was implanted into the scleral pocket of a rabbit and electrical evoked potential (EEP) signals with a threshold of 100 microA were obtained. We also fabricated a simulator with 64 microchips that has 576 electrodes (9 electrodes in a microchip times 64 microchips).

A multi-chip-architecture based flexible stimulation device for retinal prosthesis with a flip-chip packaging technique.

In the present work, we designed a multi-chip-architecture based flexible neural stimulation device for retinal prosthesis. Based on the multi-chip architecture, a novel CMOS stimulation device was successfully designed and characterized. A packaging technique for thin, flexible neural stimulation device was also proposed and demonstrated. Flip-chip bonding technology plays an essential role in the fabrication of the present thin and flexible neural stimulation device.

A case of type 2 diabetes with high levels of plasma and urinary C-peptide.

By screening 204 diabetes patients, a male with age 38 was found to have increased C-peptide levels in plasma (over 6 ng/ml) and urine (430 microg/day), both of which were the highest among the screened subjects. He developed type 2 diabetes at age 31, without history of obesity (weight was 52 kg and height 170 cm). He had bilateral testicular atrophy. Fasting plasma glucose level was 160 mg/dl and HbA1c was 8% at age 38. There was hypertriglycemia (290-662 mg/dl). There were no abnormal peaks of IRI or CPR in the serum fractionated by gel filtration (Biogel P 30). Molar ratio of p-CPR/s-IRI was 10.8. Islet cell antibody, anti-insulin binding antibody and anti-insulin receptor antibody were negative. LSH and FSH were both elevated, and free testosterone was decreased. TSH and Leptin levels were elevated. Other laboratory data were within normal range. CT scan revealed fatty liver and horse-shoe kidney. These clinical pictures do not match the criteria to known syndromes associated with diabetes. Although the single case report is insufficient to discuss the C-peptide mechanism of action, this case may give us a hint to understand an aspect of the pathophysiology of C-peptide's bioactivity dysfunction.

Meta-analysis of three diabetes population studies: association of inactive ALDH2 genotype with maternal inheritance of diabetes.

To date, there have been three population studies that examined the association of mitochondrial aldehyde dehydrogenase 2 (ALDH2) genotype with inheritance of diabetes. Here, we summarize the results by meta-analysis. The study 1 consisted of 212 type 2 diabetics who did not have renal failure. The study 2 consisted of 73 type 2 diabetics who had renal failure. The study 3 consisted of 230 type 1 diabetics. In total, 515 subjects were examined for the association of ALDH2 genotype with inheritance of diabetes. Out of 515 subjects, 307 (60%) had active ALDH2 (ALDH2*1/ALDH2*1) and 208 (40%) had inactive ALDH2 (175 had ALDH2*1/ALDH2*2 and 33 had ALDH2*2/ALDH2*2). As for family history, 25 subjects (8.1%) in the active ALDH2 group had a diabetic mother, compared with 43 (20.6%) in the inactive ALDH2 group. Twenty-nine subjects (9.4%) in the active ALDH2 group had a diabetic father, compared with 14 (6.7%) in the inactive ALDH2 group. The percentage of diabetic mother was higher in the inactive ALDH2 group, the differences were statistically significant (P < 0.0001). We hence speculate that diabetic patients with inactive ALDH2 genotype may have underlying background of mitochondria etiology, thereby showing maternal trait of diabetes inheritance. In conclusion, meta-analysis using three diabetes population studies strongly confirmed the association between ALDH2 inactivity and maternal inheritance.

Lipoma and opthalmoplegia in mitochondrial diabetes associated with small heteroplasmy level of 3243 tRNA(Leu(UUR)) mutation.

We report a patient with mitochondrial diabetes mellitus associated with the A3243G mutation (MDM3243). The patient is a 77-year man with diabetes. At age 68, he noticed diplopia, due to superior rectus muscle palsy of the right eye. At age 70, he noticed lipoma on the right arm. The pathology of his muscle revealed some ragged-red fibers, and focal cytochrome c oxidase deficiency. Hence, he may have a pathogenetic mechanism in common with CPEO (chronic progressive external ophthalmoplegia) or mitochondria-related autoimmune disorder associated with mononeuropathy. He had the rate of 0.102% for heteroplasmy of 3243 mitochondrial DNA mutation in leukocytes. This case's heteroplasmy level is the smallest among the reported cases of MDM3243 in the literature. 3243 mitochondrial DNA mutation is known to induce a lack of uridine-modification in tRNA(Leu(UUR)) at the first letter of the anticodon, with which the third letter of the codon pairs, and decline of the pairing of the anticodon of tRNA with the codon of mRNA, suggesting the termination of polypeptide-elongation to generate premature proteins. Therefore, we speculate that these premature proteins may accumulate overtime, thereby affecting cells in target organs.

Changes in the distribution pattern of gelatin-binding protein of 28 kDa (adiponectin) in myocardial remodelling after ischaemic injury.

AIMS: Gelatin-binding protein of 28 kDa (GBP28) is a collagen-like plasma protein having a binding capacity with collagens. We investigated GBP28 role on myocardial remodelling as well as the diagnostic significance of GBP28 immunostaining in myocardial infarction. METHODS AND RESULTS: Myocardial tissues obtained from 47 autopsied hearts with infarction were immunostained with antibodies against GBP28, fibronectin, type III and IV collagens, and prolyl 4-hydroxylase. GBP28 was distributed in interstitium of infarcted lesions at an early stage. GBP28 was linearly found both along the border with vital myocardium and at the periphery of surviving cardiomyocyte around the lesion at granulative stage. However, it was not observed in the scar. GBP28 distribution patterns were similar to those of fibronectin in infarcted lesions and those of type IV collagen at the periphery of cardiomyocyte. Type III collagen was not recognized in the early-stage lesion but increased along with scar maturation. Prolyl 4-hydroxylase was found in surviving cardiomyocytes around the lesion during all stages and in interstitial cells appeared in granulation tissue. CONCLUSION: GBP28 plays a role as a scaffold of newly formed collagen in myocardial remodelling after ischaemic injury, and GBP28 immunostaining may assist in a diagnosis of healing stage.

Silent mixed corticotroph and somatotroph macroadenomas presenting with pituitary apoplexy.

We discuss three unique cases of pituitary macroadenoma presenting with pituitary hemorrhage but without typical endocrine symptomatology. Immunohistochemical analysis indicated positive reactivity for adrenocorticotropic hormone (ACTH) and growth hormone (GH), and in situ hybridization indicated the expression of proopiomelanocortin (POMC) and GH mRNA. We designated these cases silent mixed corticotroph and somatotroph adenoma. Patient 1 was a 30-year-old man, patient 2 was a 29-year-old woman, and patient 3 was a 59-year-old woman. All patients presented with a headache of sudden onset and visual disturbance. The patients did not exhibit typical Cushing's or acromegalic features. Serum ACTH level was remarkably elevated in patient 1, and slightly elevated in patients 2 and 3. In all patients, serum GH levels were within normal range and magnetic resonance imaging revealed an intra- and suprasellar mass with pituitary hemorrhage. Transnasal pituitary surgery in the three patients disclosed a pituitary adenoma producing ACTH and GH. In patient 2, the residual adenoma reappeared along with an intratumoral hemorrhage, and was resected by secondary transnasal surgery. Silent mixed corticotroph and somatotroph adenomas are characterized by the following: no endocrine symptoms; presentation dominated by mass effect symptoms; macroadenoma presenting with acute pituitary hemorrhage; and production of both ACTH and GH.

No association of type 1 diabetes with a microsatellite marker for CTLA-4 in a Japanese population.

Susceptibility to insulin-dependent (type 1) diabetes mellitus is determined by both environmental and genetic factors. The primary gene associated with predisposition to type 1 diabetes is the human leukocyte antigen (HLA) class II gene (IDDM1). Recent studies have described linkage and association of type 1 diabetes to the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene (IDDM12)in Caucasians. CTLA-4 is a candidate gene for T-cell-mediated autoimmune diseases because it is a negative regulator of T-cell proliferation. We investigated distribution of a CTLA-4 (AT)n microsatellite marker in 118 Japanese patients with type 1 diabetes and 195 control subjects. We also investigated association between this CTLA-4 gene polymorphism and GAD65 antibody positivity in 103 of the patients. CTLA-4 microsatellite marker loci were determined by polymerase chain reaction amplification of genomic DNA and resolution of the products on sequencing gels. GAD65 antibody was detected by radioligand binding assay. There was no significant difference in the distribution of CTLA-4 alleles between patients and controls, and no difference was observed in the prevalence of CTLA-4 alleles when GAD65 antibody-positive and -negative individuals with the type 1 diabetes were compared. The present study did not support an association between the CTLA-4 microsatellite marker and type 1 diabetes in our Japanese study population.

Corticotroph cell adenoma without typical manifestations of Cushing's disease presenting with cavernous sinus syndrome following pituitary apoplexy.

This report presents a unique case of corticotroph cell adenoma in a 30-year-old man without acromegaly or features typical of Cushing's disease, who developed cavernous sinus syndrome following pituitary apoplexy. Magnetic resonance imaging revealed a large intrasellar/suprasellar mass with pituitary hemorrhage and extension of a hematoma to the anterior base of the skull. Urgent transnasal pituitary surgery revealed an acidophilic pituitary adenoma, with immunoreactivity for ACTH and GH and expression of proopiomelanocortin (POMC) and GH messenger ribonucleic acid (mRNA) demonstrated by in situ hybridization. To our knowledge, a silent corticotroph cell adenoma with GH production has never been reported. This type of adenoma may potentially enlarge and develop tumoral hemorrhage because it is free of endocrinological symptoms.

Association of the mitochondrial DNA 5178A/C polymorphism with maternal inheritance and onset of type 2 diabetes in Japanese patients.

The mitochondrial DNA 5178A/C (mt5178A/C) polymorphism is associated with longevity and adult onset diseases. We investigated an association of the mt5178A/C polymorphism with the occurrence and clinical features of type 2 diabetes. Two hundred and seventy Japanese patients with type 2 diabetes (181 men and 89 women) and 254 control subjects without diabetes were studied. Patients with mutations at position 3243 in the mitochondrial DNA were excluded. Genotype was determined by the polymerase chain reaction-restriction fragment length polymorphism method. Various clinical features including age at disease onset were compared between the patients with the mt5178A and mt5178C alleles. Mt5178C was observed more frequently in patients with type 2 diabetes than in control subjects (65.9% vs 57.9%, P = 0.058). Clear information about the maternal history of diabetes was obtained from 233 diabetic patients. Patients with a maternal history of diabetes carried the mt5178C allele (58/75, 77.3%) more frequently than did patients without a maternal history of diabetes (100/158, 63.3%; P = 0.032) and control subjects (57.9%; P = 0.002). The mean age at onset of diabetes was significantly lower in patients with mt5178C (47.6 +/- 11.4 years) than in patients with mt5178A (51.5 +/- 10.0 years; P = 0.0073). The mt5178A/C polymorphism may be associated with maternal inheritance of type 2 diabetes and may influence the age at onset through deterioration of mitochondrial function.

Immunolocalization of apolipoproteins in aortic atherosclerosis in American youths and young adults: findings from the PDAY study.

The immunohistochemical distribution of apolipoproteins in the abdominal aortas of 142 men, 15-34 years of age, collected in a cooperative multicenter study group (Pathobiological Determinants of Atherosclerosis in Youth) was examined in relationship to serum VLDL+LDL+HDL cholesterol levels. ApoB deposits were limited to the intima of specimens with intimal fibro cellular thickening or atherosclerotic lesions. Apo A-I, E and J were observed in both the intima and media of the aortas with intimal lesions. The pattern of apoJ distribution was similar to that of apoA-I and E. The distribution patterns of these apolipoproteins in these young adults were very similar to those in adults and old men seen in an earlier study. The extent of apolipoprotein distribution in the intima and media increased with age and the stage of atherosclerosis development, but was not correlated significantly with serum VLDL+LDL or HDL cholesterol levels. The infiltration of lipoprotein particles into the aortic wall seems to be more strongly associated with the progression of intimal lesions rather than with serum cholesterol levels.

Three Japanese patients from two families with generalized resistance to thyroid hormone with mutations in exon 9 of the thyroid hormone receptor beta gene.

Resistance to thyroid hormone (RTH) is a genetic disorder caused by mutations in the thyroid hormone receptor (TR) beta gene. The mutations are clustered in two regions: exon 9 and exon 10. To date, only one patient with an exon 9 mutation has been reported in Japan. We herein report three patients from two Japanese families with RTH and mutations in exon 9. A 52-year-old woman and her 18-year-old daughter, both with inappropriate secretion of TSH (SITSH) were diagnosed simultaneously with generalized RTH. Molecular analysis revealed a G345D mutation. An 11-year-old girl with SITSH, whose only manifestation was a goiter, had an R338W mutation, which is frequently associated with pituitary RTH. Thus, RTH with mutations in exon 9 of the TR beta gene is not so rare in Japan.

Aldosterone-producing adenoma with prolonged amelioration by dexamethasone.

Secretion of aldosterone from aldosterone-producing adenoma (APA) is to some degree under the control of ACTH and the suppressible effect of glucocorticoid on plasma aldosterone concentration (PAC) and blood pressure has been reported to be transient. We report a rare case of aldosteronism due to APA in which PAC and blood pressure were well controlled with small dose dexamethasone for over one year. No chimeric gene of glucocorticoid-remediable aldosteronism (GRA) was found in DNA of APA and leukocytes from peripheral blood and 17alpha-hydroxylase deficiency (17-OH-D) was ruled out by endocrinological examinations, this case indicates the possibility of an unknown mechanism of ACTH-dependent APA.

Vitamin D receptor initiation codon polymorphism influences genetic susceptibility to type 1 diabetes mellitus in the Japanese population.

BACKGROUND: Vitamin D has been shown to exert manifold immunomodulatory effects. Type 1 diabetes mellitus (T1DM) is regarded to be immune-mediated and vitamin D prevents the development of diabetes in the NOD mouse. We studied the association between T1DM and the initiation codon polymorphism in exon 2 of the vitamin D receptor gene in a Japanese population. We also investigated associations between the vitamin D receptor polymorphism and GAD65-antibody (Ab) positivity. We carried out polymerase chain reaction-restriction fragment length polymorphism analysis in 110 Japanese T1DM patients and 250 control subjects. GAD65 antibodies were assessed in 78 patients with T1DM. RESULTS: We found a significantly higher prevalence of the F allele / the FF genotype in the patients compared to the controls (P = 0.0069 and P = 0.014, respectively). Genotype and allele frequencies differed significantly between GAD65-Ab-positive patients and controls (P = 0.017 and P = 0.012, respectively), but neither between GAD65-Ab-negative patients and controls (P = 0.68 and P = 0.66, respectively) nor between GAD65-Ab-positive and -negative patients (P = 0.19 and P = 0.16, respectively). CONCLUSIONS: Our findings suggest that the vitamin D receptor initiation codon polymorphism influences genetic susceptibility to T1DM among the Japanese. This polymorphism is also associated with GAD65-Ab-positive T1DM, although the absence of a significant difference between GAD65-Ab-negative patients and controls might be simply due to the small sample size of patients tested for GAD65 antibodies.