Mutation analysis of a Japanese patient with fucosidosis

Fucosidosis is a rare autosomal recessive disorder resulting from a deficiency of α-L-fucosidase. Recently, various mutations have been reported in this disease, but it is difficult to elucidate the phenotype from the genetic mutations. We report a patient with chronic infantile type fucosidosis, with a compound heterozygote of a nonsense mutation (W148X, Trp at codon 148 to stop codon) and a large deletion, including all exons. This is the first report of a large deletion demonstrated in fucosidosis. It is interesting that this patient has a relatively mild clinical course despite the absence of the mRNA. This case also indicates the difficulty in determining the phenotype from the genotype in fucosidosis. Received: February 19, 1999 / Accepted: April 16, 1999     

Damage to DNA purified from the radioresistant prokaryote, Deinococcus radiodurans, by acid heating

Using a highly radioresistant bacterium, Deinococcus radiodurans, the mechanism of degradation of the purified DNA molecules by heating was examined under acidic conditions. Setting the treatment temperature at 55?C with a duration of 0 to 20 min and adjusting the pH of the cell suspension to 3, 5 or 7, cell viabilities after the treatment were compared. The survival rate decreased in proportion to the reduction of pH. DNA purified from D. radiodurans was then damaged by irradiation with gamma-rays at 0.22 kGy or 1 kGy. It was considered that the radioresistance of D. radiodurans was due to its high repair capability, rather than any specificity of DNA structure. Purified D. radiodurans DNA was resistant to heating up to 90?C at neutral pH. However, marked DNA damage occurred when it was heated at pH values below 5.0. Then, DNA labeled with [3H]adenine was examined. Treatment at lower pH and higher temperature resulted in release of more adenine base, i.e., the purine ring, from the DNA molecules. Therefore, we assumed that the decrease in survival of D. radiodurans in vivo and damage to its DNA in vitro by acid heating were due to the release of adenine and guanine from the DNA, i.e., depurination.     

Carotid endarterectomy in chronic renal failure patients: report of two cases

Chronic renal failure is one of the risk factors for carotid atherosclerosis. We report two cases of stenosis of the carotid bifurcation treated by carotid endarterectomy. A 66-year-old man with a 17-year history of hemodialysis experienced repeated episodes of right hemiparesis. Cerebral angiography showed severe stenosis of the cervical carotid bifurcation bilaterally. Left and right carotid endarterectomy operations were performed one month apart. The postoperative course was uneventful, and the patient returned home without neurological symptoms. The second case was in a 49-year-old woman with a 15-year history of hemodialysis had vertigo of one month duration. Cerebral angiography revealed occlusion of the left subclavian artery, and the distal left axillary artery was filled by retrograde flow from the left vertebral artery. Stenosis of the right carotid bifurcation was also noted. Right carotid endarterectomy was performed without any complications. Although a high incidence of intraoperative complications and of recurrent stroke after carotid endarterectomy (CEA) has been reported in chronic renal failure patients, the poor prognosis of the natural history of severe carotid stenosis in chronic renal failure should be taken into consideration. The cases reported indicate that carotid endarterectomy is safe and justified for carotid stenosis in chronic renal failure patients.     

Electroporation-mediated PDGF receptor-IgG chimera gene transfer ameliorates experimental glomerulonephritis

BACKGROUND: Mesangial cell proliferation and phenotypic alteration occur in an early phase of glomerular injury and precede increased extracellular matrix accumulation. A critical growth factor responsible for mesangial proliferation is platelet-derived growth factor (PDGF), which has proved to be a potent mitogen. METHODS: We generated a chimeric cDNA encoding an extracellular domain of the beta-PDGF receptor fused with IgG-Fc, termed PDGFR/Fc, and examined the feasibility of gene therapy targeting PDGF using PDGFR/Fc. RESULTS: Chimeric PDGFR/Fc molecule completely inhibited the tyrosine phosphorylation of beta-PDGF receptors and cellular proliferation induced by PDGF in vitro. We then introduced the PDGFR/Fc expression vector into the muscle of anti-Thy-1 model of glomerulonephritic rats by electroporation. The plasma concentration of chimeric PDGFR/Fc levels was 244.4 +/- 89.8 ng/mL four days after transfection. On day 5, PDGFR/Fc gene transfer significantly reduced the number of PCNA-positive cells and glomerular cell numbers by 59.6 and 23.2%, respectively. Northern blot analysis demonstrated that glomerular mRNA levels of alpha-smooth muscle action, transforming growth factor-beta 1, and type I collagen were also suppressed on days 5 and 7 by the PDGFR/Fc transfection. There was a significant reduction in the matrix score of the transfected nephritic rats (2.91 +/- 0.75 and 2.06 +/- 0.95; disease control group vs. treated group, P < 0.001). CONCLUSION: These results suggest that gene therapy by the manipulation of PDGF action using electroporation-mediated PDGFR/Fc gene transfer to the skeletal muscle might be a useful treatment for mesangioproliferative glomerulonephritis.     

Maximum Preservation of the Media in Carotid Endarterectomy

Carotid endarterectomy (CEA) is intended to remove atheromatous plaque by dissecting a plane between the intima and the media (circular medial fibers), but this may not be the optimal dissection plane. The present technique is based on identifying the plane that divides the media from the plaque, so preserving the media on the adventitia as much as possible. This plane is more difficult to find and follow than the easy-to-dissect plane usually located between the media and the adventitia, because the plaque invades the media and so the dividing plane is located within the media. In this prospective observational study, CEA was performed in 22 patients to histologically examine the excised plaques and small samples of the whole arterial wall, and evaluate the clinical outcomes. Plaque had invaded the luminal part of the media in the whole arterial wall sample of 80% of cases. Thin medial layers covering > 80% of the surface of the plaque were found in 16 of 22 plaques (73%). Some atheromatous component was sometimes left in the preserved media, rather than completely removed with the media. No morbidity or mortality had occurred by discharge. Only 1 small ipsilateral infarction (4.5%) and no restenosis of greater than 50% were detected during the mean follow-up period of 7 years. Since the plaque usually invades the media, the optimum dissection plane may be located within the media, dividing it into two layers. The presence of some remnant atheromatous components in the preserved media was not associated with surgical complications or restenosis.     

Heme oxygenase‐1: a new drug target in oxidative tissue injuries in critically ill conditions

Oxidative stresses associated with ischemia/reperfusion, neutrophil activation, and anesthesia with certain volatile agents, etc., are thought to play an important role in the development of acute organ failure in critical illnesses, such as acute lung injury, acute coronary artery insufficiency, acute liver failure, acute renal failure, and multiple organ dysfunction syndrome. Such oxidative stressors provoke a set of cellular responses, particularly those that participate in the defense against tissue injuries. Free heme, which can be rapidly released from hemeproteins, may constitute a major threat in the oxidant stress because it catalyzes the formation of reactive oxygen species. To counteract such insults, cells respond by inducing the 33‐kDa heat shock protein, heme oxygenase (HO)‐1, the rate‐limiting enzyme in heme degradation. Induced HO‐1 as such removes free heme by an enzymatic process. In addition, HO‐1 induction itself confers protection to tissues from further oxidative injuries. In contrast, the abrogation of HO‐1 induction, or chemical ablation of HO activity abolishes the beneficial effect of HO‐1, and results in the aggravation of tissue injuries. In this article, we review recent advances in the essential role of HO‐1 in tissue protection in various models of experimental oxidative tissue injuries as well as in human disorders, which is related to critically ill conditions, with special emphasis on the role of its induction in tissue defense and its potential therapeutic implications. Drug Dev. Res. 67:130–153, 2006. © 2006 Wiley‐Liss, Inc.     

Carcinogenicity of 1,2-dimethylhydrazine dihydrochloride in BALB/c mice

Summary The carcinogenicity of 1,2-dimethylhydrazine dihydrochloride (DMH) by oral, intragastric and subcutaneous administration was examined in 339 BALB/c mice. Subcutaneous injection of DMH induced intestinal tumors in the lower colon of all mice. After oral administration it induced a high incidence of vascular tumors in the liver and soft tissues, but colon tumors were found in only 2 mice when given at a high dosage. On intragastric administration, it induced a fairly high incidence both of colon and vascular tumors. The sites and incidences of vascular tumors and squamous cell carcinomas of the perianal glands were also described.This work was supported in part by a Grant-in Aid for Cancer Research from the Ministry of Education, Japan.     

High-frequency inter-parental recombination between mitochondrial genomes of rice cybrids

Analyzing more than 100 independent rice cybrids, we found evidence for inter-molecular recombination between parental mitochondrial genomes occurring at high frequency soon after protoplast fusion. The structure of the region around the atp6 gene showed extensive polymorphism among Indica (MTC-5A), Japonica (Nipponbare), and wild abortive (IR58024A) mitochondrial genomes. Recombination between the mitochondrial genomes of IR58024A and MTC-5A around the atp6 gene was detected by Southern-blot analysis of cybrid plants. Such recombinant mitochondrial molecules were also cloned from IR58024A/Nipponbare cybrid callus. PCR analysis around the atp6 gene demonstrated that inter-parental recombination occurs in practically all cybrid calli within 2 weeks after protoplast fusion. At this point, parental and recombinant mitochondrial genomes coexisted within the callus. Over the course of further cultivation, however, mitochondrial genome diversity decreased as parental and/or recombinant genomes segregated out.