Diabetes mellitus carrying a mutation in the mitochondrial tRNALeu(UUR) gene

Summary We screened 214 Japanese NIDDM (non-insulin-dependent) diabetic patients with a family history of diabetes for mutations in the mitochondrial tRNA^Leu(UUR) gene using polymerase chain reaction-restriction fragment length polymorphism and direct sequencing. Six patients were identified as having an A to G transition at position 3243 (3243 mutation), but no patients were detected with a T to C transition at position 3271, in the mitochondrial tRNA^Leu(UUR) gene. These two mutations were not present in 85 healthy control subjects. It was disclosed that the patients' mothers were also affected by diabetes mellitus in five of the six cases. In these six affected patients, the 3243 mutation shows variable phenotypes, such as the degree of multiple organ involvement, intrafamilial and interfamilial differences in disease characteristics, and the degree of the involvement of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) phenotype. Endocrinological examinations revealed that those diabetic patients with the 3243 mutation show not only beta-cell dysfunction, but also a defect in alpha-cell function, which is considered characteristic of diabetes with the 3243 mutation. When compared with 50 selected diabetic control subjects without the 3243 mutation, whose mothers, but not fathers, were found to have diabetes, it was established statistically that those with the 3243 mutation possess the following clinical characteristics; 1) the age of diabetes onset is lower, 2) they have lean body constitutions, and 3) they are more likely to be treated with insulin than control subjects. We suggest that diabetes with the 3243 mutation possesses phenotypes distinct from those in common forms of diabetes.Abbreviations NIDDM non-insulin-dependent diabetes mellitus - IDDM insulin-dependent diabetes mellitus - MELAS mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes - PCR polymerase chain reaction - RFLP restriction fragment length polymorphism - BMI body mass index - ICA islet cell antibody - ICSA islet cell surface antibody - GAD glutamic acid decarboxylase     

Relationship between navicular drop and measuring position of maximal plantar flexion torque of the first and second-fifth metatarsophalangeal joints

[Purpose] The purpose of this study was to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Subjects] Ten healthy young men participated in this study. [Methods] The Pearson product-moment correlation coefficient was calculated to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Results] Significant negative correlations were observed between navicular drop and plantar flexion torques in the lengthened position of the intrinsic toe plantar flexion muscles, but no correlations were found between navicular drop and plantar flexion torques in the neutral position of the ankle and metatarsophalangeal joints. Moreover, the intrinsic toe plantar flexion muscles were found to contribute to the formation of the medial longitudinal arch. [Conclusion] Navicular drop correlates with metatarsophalangeal joint muscle strength in plantar flexion where the intrinsic toe muscles are capable of exerting force.Key words: Toe flexor strength, Intrinsic foot muscle, Medial longitudinal arch     

Impact of Weekly Teriparatide on the Bone and Mineral Metabolism in Hemodialysis Patients With Relatively Low Serum Parathyroid Hormone: A Pilot Study

Adynamic bone disease in HD patients is characterized by skeletal resistance to parathyroid hormone (PTH) or suppression of PTH release, leading to a downregulated bone turnover and bone fracture. Hence, we examined the efficacy of weekly teriparatide for HD patients with low PTH indicating adynamic bone disease without a history of parathyroidectomy. Fifteen HD patients with low PTH were recruited in this prospective observational study. Of them, 10 received teriparatide for 12 months and five nontreated patients were enrolled as control. Primary outcomes were defined as the changes in bone mineral density and bone turnover markers. Bone mineral density at the lumbar spine increased by 3.7% and 2.5% at 6 and 12 months, respectively, and bone formation markers increased, while bone resorption markers did not change in the teriparatide group. At 12 months after teriparatide administration, endogenous PTH was secreted followed by the recovery of low bone turnover. 40% of patients in the teriparatide group dropped out due to adverse events and the most common adverse event was transient hypotension. This study suggests that weekly teriparatide for HD patients with low PTH in the absence of parathyroidectomy accelerates bone formation and bone turnover, leading to increased trabecular bone mass and secretion of endogenous PTH.     

Neurotrophin production in brain pericytes during hypoxia: a role of pericytes for neuroprotection

Neurotrophins are crucial regulators of neuronal survival and death. Evidence suggests that cells comprising the neurovascular unit (NVU) cooperatively mediate neuronal development, survival and regeneration. The aim of this study was to test whether cerebrovascular cells, endothelial cells and pericytes, produce neurotrophins and play neuroprotective roles during hypoxic insults. We examined the expression of neurotrophins and their receptors in cultured human cerebral microvascular endothelial cells and pericytes, astrocytes and the rat neuronal cell line PC12. Differentiated PC12 cells expressed TrkA, the NGF receptor, which was significantly upregulated by hypoxia at 1% O(2) and regulated neuronal survival. Both pericytes and astrocytes expressed three neurotrophins, i.e. NGF, BDNF and NT-3, while TrkB and TrkC, specific receptors for BDNF and NT-3, were expressed in astrocytes, but not pericytes. In response to hypoxia, among the neurotrophins expressed in pericytes and astrocytes only NT-3 expression was significantly upregulated in pericytes. Treatment of astrocytes with NT-3 significantly activated Erk1/2 and increased the expression of NGF both at mRNA and protein levels. The MEK1 inhibitor U0126 or siRNA-mediated knockdown of TrkC abolished the NT-3-induced upregulation of NGF in astrocytes. Taken together, cerebral microvascular pericytes and astrocytes are potent producers of neurotrophins in the NVU. In response to hypoxia, pericytes increase NT-3 production, which induces astrocytes to increase NGF production through the TrkC-Erk1/2 pathway. The interplay between pericytes and astrocytes through neurotrophins in the NVU may play an important role in neuronal survival under hypoxic conditions.     

Determinants of in-hospital death in patients with postinfarction ventricular septal perforation

Ventricular septal perforation (VSP) is a serious complication associated with acute myocardial infarction (MI). The purpose of this study was to investigate the determinants of in-hospital death in patients with postinfarction VSP. Between January 1990 and April 2010, we identified 37 patients from our hospital records. Univariate analysis and multivariate logistic regression analysis were performed to find the determinants of in-hospital death. In-hospital mortality was 35% (13/37 patients). History of hypertension (P = 0.03), percutaneous coronary intervention (P = 0.04), and preoperative percutaneous cardiopulmonary support (P = 0.04) were associated with in-hospital death, whereas history of hyperlipidemia was associated with in-hospital survival. The interval from MI to VSP in survivors was significantly longer than that in nonsurvivors (P < 0.01). In multivariate logistic regression analysis, a shorter interval from MI to VSP (odds ratio 0.57, 95% confidence interval 0.34-0.95, P = 0.03) was found to be an independent predictor of in-hospital death. In conclusion, in-hospital mortality was high in patients with postinfarction VSP. A shorter interval from MI to VSP was a significant independent predictor of in-hospital death.     

Monosomy 13 in metaphase spreads is a predictor of poor long-term outcome after bortezomib plus dexamethasone treatment for relapsed/refractory multiple myeloma

We retrospectively investigated the prognostic impact of high-risk cytogenetic abnormalities (CAs) on the outcome of treatment with bortezomib plus dexamethasone (BD) in 43 relapsed/refractory (Rel/Ref) multiple myeloma patients. Fluorescence in situ hybridization (FISH) analysis identified del(13q) in 25 patients, t(4;14) in 14, t(14;16) in 4, 1q21 abnormality in 12 and del(17p) in 2, while G-banding also detected chromosome 13 monosomy (-13) in metaphase spreads from 7 patients. Eighteen of 25 patients with FISH-detected chromosome 13 abnormalities also exhibited other abnormalities. Median observation period was 510 days, and median overall survival (OS) and progression-free survival (PFS) were 912 days and 162 days, respectively. Detection of del(13q), t(4;14), t(14;16) or 1q21 abnormalities by FISH and co-occurrence of chromosome 13 abnormality with other abnormalities were not associated with poorer outcomes. In contrast, detection of -13 by G-banding in metaphase spreads showed significant association with shorter OS, although the overall response rate and PFS were not inferior to those for patients without -13 detected by G-banding. BD therapy may be a potent weapon for overcoming most classical high-risk CAs, while the detection of -13 in metaphase spreads may serve as a predictor of highly progressive disease, even when treated with BD.