Comprehensive screening of multiple epiphyseal dysplasia mutations in Japanese population

Multiple epiphyseal dysplasia (MED) is among the most genetically heterogeneous skeletal dysplasias. Six genes involved in MED, COMP, MATN3, COL9A1, COL9A2, COL9A3, and DTDST have been identified; however, the presence of additional disease genes has been reported, and the detection rate for mutations in known genes accounts for no more than 50% of patients with MED in Western populations. Here, we screened the six known disease genes in 35 consecutive Japanese MED patients. We analyzed the entire coding region of each gene, along with flanking intron-exon junctions, by direct sequencing. A total of 19 mutations were identified in COMP, MATN3, COL9A2, COL9A3, and DTDST. The detection rate for known mutations was higher in this study than in previous reports, and we identified a substantially different spectrum of mutations. Mutations in MATN3 were more prevalent among these Japanese patients, whereas no DTDST mutations were detected. Most of the mutations were localized within specific regions of each gene: COMP mutations were found in the calmodulin-like repeat domains; MATN3 mutations in the von Willebrand factor type A domain; and type IX collagen gene mutations occurred in the third collagenous domains. Based on the integration of clinical and genetic information, we propose an algorithm for detecting mutations in Japanese MED patients. Our study further supports the existence of additional MED gene(s).     

A 90-day oral toxicity study of nisin A,an anti-microbial peptide derived from Lactococcus lactis subsp. lactis,in F344 rats

This study was designed to evaluate and characterize any adverse effect of nisin A, when administered to both sexes of F344/DuCrlCrlj rats (10 males and 10 females in each group) at dietary levels of 0%, 0.2%, 1.0% and 5.0% for 90 days. Animals given NaCl at a dietary level of 3.712% (equivalent to the NaCl content in 5.0% nisin A diet) served as a reference material treated group.There were no deaths, and the treatment had no toxicologically significant effects on clinical signs, body weights, food consumption, ophthalmology, hematology, or gross pathology.Statistically significant increases of water consumption, urine volume, and urinary sodium and chlorine, and decreases of urinary potassium and serum sodium, along with increases of absolute and relative kidney weight, and incidences of minimal squamous cell hyperplasia of limiting ridge in the forestomach, were found in nisin A-treated groups. It was considered that these changes were related to NaCl, since they were also noted in rats given diet containing the reference substance.Thus, no toxicologically significant changes were apparent in both sexes of F344/DuCrlCrlj rats fed diet containing 0%, 0.2%, 1.0% and 5.0% nisin A for 90 days. Therefore, the no-observed-adverse-effect level (NOAEL) for nisin A was concluded to be a dietary level of 5.0% (2996 mg/kg/day for males and 3187 mg/kg/day for females).     

Erythropoietin prevents vascular inflammation and oxidative stress in subtotal nephrectomized rat aorta beyond haematopoiesis

1. Recombinant human erythropoietin (rHuEPO) has been used for the management of renal anaemia. Recent studies suggest pleiotropic properties of rHuEPO in various tissues. The aim of the present study was to investigate the vasoprotective effects of rHuEPO in renal failure rats. 2. Rats subjected to 5/6 and 17/18 nephrectomy (5/6Nx and 17/18Nx rats, respectively) were treated with rHuEPO (75 U/kg, s.c.) three times a week for 2 weeks. 3. Administration of rHuEPO to 5/6Nx or 17/18Nx rats had no effect on systolic blood pressure or decreased haematocrit. However, rHuEPO treatment normalized proteinuria and creatinine clearance in 5/6Nx, but not in 17/18Nx, rats. 4. Vasodilation in response to acetylcholine in aortic rings was impaired in 5/6Nx and 17/18Nx rats and improved by rHuEPO in both groups. Immunohistochemical analysis revealed that macrophage infiltration into adventitial areas and the expression of osteopontin were enhanced in aortas from 5/6Nx and 17/18Nx rats, but that rHuEPO suppressed these effects. In addition, rHuEPO attenuated medial hyperplasia and NADPH oxidase‐derived superoxide production in 5/6Nx and 17/18Nx rats. 5. Activation of the Akt signalling pathway was evident in rHuEPO‐treated rats as the increased expression of phosphorylated Akt and glycogen synthase kinase‐3β. Treatment with rHuEPO restored the expression of phosphorylated endothelial nitric oxide synthase in the aorta and urinary excretion of NO_x in nephrectomized rats. 6. These results suggest that a low dose of rHuEPO results in the normalization of endothelial function, vascular inflammation and oxidative stress in rats with renal ablation beyond haematopoiesis. In addition, these vasoprotective effects are observed even in a state of deteriorating renal dysfunction.     

A decrease of cell proliferation by hypothermia in the hippocampus of the neonatal rat

Hypothermia is a potential therapy for cerebral hypoxic ischemic injury of not only adults but also neonates. However, the side effects of hypothermia in the developing brain, where a massive amount of neurogenesis occurs, remain unclear. We investigated the proliferation of neural progenitor cells by systemic application of the thymidine analog 5-bromodeoxyuridine (BrdU) in neonatal rats in a severe hypothermic environment. The rat pups were divided into two groups, a hypothermia group (30 degrees C: n=10) and a normothermia group (37 degrees C: n=10). After the pups were placed for 21 h in each environment, 100 mg/kg/day of BrdU was injected intraperitoneally to label dividing cells, and then the pups were sacrificed at 24 h. We examined the number of BrdU-labeled cells in the subventricular zone of the periventricle and the subgranular zone of the dentate gyrus. In the hypothermic environment, BrdU-labeled cells significantly decreased in number in the dentate gyrus, but not in the periventricular region. Thus, the severe hypothermic environment induced a decrease of neurogenesis in the neonatal rat. These observations are noteworthy regarding clinical hypothermia therapy following cerebral hypoxic ischemic injury during the perinatal period.     

Clinical and MRI features of Japanese patients with multiple sclerosis positive for NMO-IgG

This study investigates the relation between the serological status of NMO (neuromyelitis optica)-IgG and the clinical and MRI features in Japanese patients with multiple sclerosis. Serum NMO-IgG was tested in 35 Japanese patients diagnosed with multiple sclerosis, including 19 with the optic-spinal form of multiple sclerosis (OSMS), three with the spinal form of multiple sclerosis (SMS), and 13 with the conventional form of multiple sclerosis (CMS), which affects the brain. NMO-IgG was detected in 14 patients, 12 with OSMS and 2 with CMS. In these patients, longitudinally extensive (> 3 vertebral segments) spinal cord lesions (93% v 57%) and permanent, complete blindness (no perception of light) in at least one eye (50% v 0%) were the noticeable features as compared with NMO-IgG-negative OSMS. The two patients having CMS with NMO-IgG had unusual brain lesions, but in other respects had features suggesting OSMS. NMO-IgG was detected in more than half the number of patients with OSMS and in some patients with CMS. This newly discovered serum autoantibody was markedly associated with longitudinally extensive spinal cord lesions and with complete blindness, suggesting severe optic-spinal disease.     

A left ventricular noncompaction in a patient with long QT syndrome caused by a KCNQ1 mutation: a case report

A 5-year-old girl developed cardiopulmonary arrest after crying. From the electrocardiogram and echocardiography, a left ventricular noncompaction (LVNC) with long QT syndrome (LQT) was suspected as the cause of the cardiopulmonary arrest, and treatment with a β-blocker and a calcium antagonist was then begun. A genetic screening of LQT-related genes revealed a previously reported heterozygous KCNQ1 mutation. The association of LVNC and LQT is an extremely rare condition, and long-term treatment based on the characteristics of both disorders is required. Also, the association of cardiomyopathy and LQT could become a new clinical entity in the future.     

Refractoriness to platelet transfusion in acute myeloid leukemia correlated with the optical density of anti-platelet factor 4/heparin antibodies

A small number of reports have described cases of heparin-induced thrombocytopenia complicating hematological disorders with impaired platelet production. We describe the case of a 66-year-old woman with acute myeloid leukemia who exhibited unexplained refractoriness to platelet transfusion, while receiving heparin flushes, and was found to have anti-platelet factor 4 (PF4)/heparin antibodies with high optical density (OD) values (>2 units) detected by an enzyme-linked immunosorbent assay. After cessation of heparin flushes, her refractoriness to platelet transfusion resolved. We retrospectively confirmed that the OD values for anti-PF4/heparin antibodies declined gradually; refractoriness to platelet transfusion resolved when the OD values fell below 1.0 units. Given the absence of any other evident explanation for this phenomenon, and the correlation between the OD values for anti-PF4/heparin antibodies and the efficacy of platelet transfusions, we conclude that the patient’s refractoriness to platelet transfusion was most likely caused by anti-PF4/heparin antibodies that had platelet-activating properties.     

Estrogen Receptor α Induction by Mitoxantrone Increases Abcg2 Expression in Placental Trophoblast Cells

Substrate‐induced upregulation of ATP‐binding cassette subfamily G member 2 (ABCG2) has been well studied in cancer cells, but it is also important to understand whether ABCG2 is upregulated by its substrates in tissues in which it is constitutively expressed. In the present study, we aimed to clarify the regulatory mechanism of Abcg2 expression by its substrate, mitoxantrone, in placental cells. Abcg2 mRNA expression in rat placental TR‐TBT 18d‐1 cells treated with 10 μM mitoxantrone for 24 h was increased, compared with that in nontreated cells, whereas 10 μM pheophorbide‐a had no effect. Methylated CpG level in the promoter region of the Abcg2 gene was low and was not altered by mitoxantrone. On the contrary, mitoxantrone markedly increased the expression of estrogen receptor (ER) α and progesterone receptor (PR) B. Fulvestrant, an ER antagonist, attenuated the mitoxantrone‐induced increase of Abcg2 mRNA expression, whereas mifepristone, a PR antagonist, had little effect. 17β‐estradiol, an ER ligand, positively regulated the mitoxantrone‐induced increase of Abcg2 expression. DNA demethylation by 5‐aza‐2‐deoxycytidine treatment increased ERα expression, but mitoxantrone failed to facilitate the demethylation of ERα promoter in TR‐TBT 18d‐1 cells. In conclusion, Abcg2 expression is induced by mitoxantrone via the induction of ERα in TR‐TBT 18d‐1 cells.