Molecular and clinical analysis of Japanese patients with 3-hydroxy-3-methylglutaryl CoA lyase (HL) deficiency

Deficiency of mitochondrial 3-hydroxy-3-methylglutaryl CoA lyase (HL, EC4.1.3.4.) is an autosomal recessive genetic disorder characterized by acute episodes of vomiting, hypotonia, and lethargy in the neonatal period or in infancy. Except in Saudi Arabia, where HL deficiency is the most common organic acidemia, the disorder is quite rare with only 41 cases being reported in the English literature, and only five known cases among Japanese. In this study, we present the results of a molecular analysis of all five Japanese patients together with their clinical phenotypes. Five different mutations in the HL gene were identified: one large deletion, one nonsense mutation, one missense mutation, and two splice mutations. Except for G835A (E279K) with its relatively common occurrence among Japanese, these mutations were unique to each family. The results of expression studies with mutated HL cDNAs confirmed the pathogenicity of these mutations and supported the importance of previously identified functional domains of the HL molecule, i.e., the putative catalytic site or dimerization site. In addition, we identified an alternative splicing event that resulted in the skipping of exons 5 and 6. This alternatively spliced product did not show HL activity and was present in various tissues of normal subjects. Clinically, all patients presented with similar symptoms, except that the timing of the initial presentation varied considerably, from 1 day to 1 year 3 months. In general, patients with null-activity mutations presented earlier in life, whereas those with residual activities presented later.     

Combined Use of Bacteriophage Typing and Pulsed-Field Gel Electrophoresis in the Epidemiological Analysis of Japanese Isolates of Enterohemorrhagic Escherichia coli O157:H7

A total of 236 enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates in Japan were investigated by bacteriophage typing, and the results were compared with those of pulsed-field gel electrophoresis (PFGE). Seven phage types (PTs) were observed in 71 isolates which were derived from 22 outbreaks. All of the isolates from ten outbreaks in the Kinki region (midwestern part of Japan) in July-August 1996 were grouped into the same PFGE type (IIa) and PT 32, while among total isolates, there were such varieties as PFGE type IIa containing five phage types and PT32 containing two PFGE types. These results suggest that the ten outbreaks should be considered to be a single outbreak, and show that the combined use of bacteriophage typing and PFGE enhances reliability in epidemiological surveys.     

Late-onset porphyrias: what are they?

Porphyrias are inherited disorders of heme biosynthesis. ALA dehydratase porphyria (ADP) and congenital erythropoietic porphyria (CEP) are autosomal recessive porphyrias, and are typically expressed at birth or in childhood. However, a few cases of late-onset recessive porphyrias have been reported. Recently we encountered a late-onset ADP patient who developed symptoms of acute porphyria when he was 63 years old. This was accompanied by polycythemia vera. It was concluded that he developed the porphyria because an abnormal ALAD allele was clonally expanded by polycythemia vera. Upon reviewing the literature, a few cases of late-onset CEP were found to be also associated with hematologic abnormalities suggestive of myelodysplastic syndrome (MDS), another clonal disorder. These findings suggest that these late-onset porphyrias may be heterozygous for their gene defects, but clinical expression may be elicited if there is a loss of heterozygosity, either by a clonal expansion of the porphyric allele or by a loss of function mutation in the other allele.     

Eye-Head Coordination for Visual Cognitive Processing

We investigated coordinated movements between the eyes and head (“eye-head coordination”) in relation to vision for action. Several studies have measured eye and head movements during a single gaze shift, focusing on the mechanisms of motor control during eye-head coordination. However, in everyday life, gaze shifts occur sequentially and are accompanied by movements of the head and body. Under such conditions, visual cognitive processing influences eye movements and might also influence eye-head coordination because sequential gaze shifts include cycles of visual processing (fixation) and data acquisition (gaze shifts). In the present study, we examined how the eyes and head move in coordination during visual search in a large visual field. Subjects moved their eyes, head, and body without restriction inside a 360° visual display system. We found patterns of eye-head coordination that differed those observed in single gaze-shift studies. First, we frequently observed multiple saccades during one continuous head movement, and the contribution of head movement to gaze shifts increased as the number of saccades increased. This relationship between head movements and sequential gaze shifts suggests eye-head coordination over several saccade-fixation sequences; this could be related to cognitive processing because saccade-fixation cycles are the result of visual cognitive processing. Second, distribution bias of eye position during gaze fixation was highly correlated with head orientation. The distribution peak of eye position was biased in the same direction as head orientation. This influence of head orientation suggests that eye-head coordination is involved in gaze fixation, when the visual system processes retinal information. This further supports the role of eye-head coordination in visual cognitive processing.     

Sex determination using the femur in an ancient Anatolian population

Determination of sex from the femur measurements has been attempted in several populations. Numerous studies have also demonstrated the importance of creating population specific standards in the metric assessment of sex. The present study attempts to establish metric standards for sex determination by using femur measurements for ancient Anatolian populations. Osteometric data were obtained from skeletal remains of 130 adults (67 males and 63 females) from the Dilkaya medieval collection. Eight femur measurements were taken and the data were analyzed using t-test and discriminant analysis with the help of Statistical Package for the Social Sciences (SPSS). The basic statistics showed that all measurements were sexually dimorphic. For the univariate discriminant function derived, precision of sex determination was 86.5 % with the condyle breadth. Our prediction values showed that sex differentiation can be done by femur measurements with reliability between 76 % and 88.5 %, with values for female slightly higher than for males. It is suggested that discriminant formulas developed by combinations of femur measurements in this study can be used for sex determination accurately on fragmentary skeletal remains in ancient Anatolian populations.     

Electrolyzed Reduced Water Supplemented with Platinum Nanoparticles Suppresses Promotion of Two-stage Cell Transformation

In the two-stage cell transformation theory, cancer cells first receive initiation, which is mainly caused by DNA damage, and then promotion, which enhances transformation. Murine Balb/c 3T3 cells are widely used for transformation experiments because they lose contact inhibition ability when transformed. Electrolyzed reduced water (ERW), which is produced near a cathode during electrolysis of water, is an alkaline drinking water that is beneficial to health. ERW contains a high concentration of dissolved hydrogen and scavenge reactive oxygen species (ROS), along with a small amount of platinum (Pt) nanoparticles (Pt nps) derived from Pt-coated titanium electrodes. Pt nps stably disperse in aqueous solution for a long time, and convert hydrogen molecules to active hydrogen (atomic hydrogen) that can scavenge ROS. Therefore, ERW supplemented with synthesized Pt nps is a model strong reduced water. This is the first report that ERW supplemented with synthesized Pt nps strongly prevents transformation of Balb/c 3T3 cells. ERW was prepared by electrolysis of 0.002 M NaOH solution using a batch-type electrolysis device. Balb/c 3T3 cells were treated with 3-methyl cholanthrene (MCA) as an initiation substance, followed by treatment with phorbol-12-myristate-13-acetate (PMA) as a promotion substance. MCA/PMA-induced formation of a transformation focus was strongly suppressed by ERW supplemented with Pt nps but not by ERW or Pt nps individually. ERW supplemented with Pt nps suppressed transformation at the promoter stage, not at initiation, suggesting that ERW supplemented with Pt nps suppressed the PMA-induced augmentation of intracellular ROS. ERW supplemented with Pt nps is a potential new antioxidant against carcinogenesis.     

Human Herpesvirus-6 U14 Induces Cell-Cycle Arrest in G2/M Phase by Associating with a Cellular Protein,EDD

The human herpesvirus-6 (HHV-6) infection induces cell-cycle arrest. In this study, we found that the HHV-6-encoded U14 protein induced cell-cycle arrest at G2/M phase via an association with the cellular protein EDD, a mediator of DNA-damage signal transduction. In the early phase of HHV-6 infection, U14 colocalized with EDD dots in the nucleus, and similar colocalization was also observed in cells transfected with a U14 expression vector. When the carboxyl-terminal region of U14 was deleted, no association of U14 and EDD was observed, and the percentage of cells in G2/M decreased relative to that in cells expressing wild-type U14, indicating that the C-terminal region of U14 and the U14–EDD association are critical for the cell-cycle arrest induced by U14. These results indicate that U14 is a G2/M checkpoint regulator encoded by HHV-6.     

Quantification and localization of erythropoietin-receptor-expressing cells in the liver of Xenopus laevis

Erythropoiesis occurs in the African clawed frog, Xenopus laevis and is mediated by erythropoietin (xlEPO), a primary regulator of this process. Previously, we have shown that the xlEPO receptor (xlEPOR), which is expressed by erythroid progenitors that respond to xlEPO, is found predominantly in the liver. The aim of the present study was to determine the dynamics of erythropoiesis in the livers of normal and anemic X. laevis by identifying the number and precise location of mature and immature erythrocytes. We quantified mature and immature erythrocyte numbers by o-dianisidine staining or immunohistochemistry and investigated the dynamics of erythropoiesis in normal, acute hemolytic and blood-loss states by in vivo cell proliferation assays with 5-bromo-2′-deoxyuridine (BrdU). We detected 0.12×10⁸ xlEPOR⁺ BrdU⁺ cells in the liver of the normal X. laevis at 24 h after BrdU injection. Frogs presenting with acute hemolytic anemia and pancytopenia show a 10-fold increase in the number of xlEPOR⁺/BrdU⁺ cells (approximately 1.30×10⁸ cells) in the liver. The xlEPOR⁺ cells are found predominantly on the inner wall of hepatic sinusoids. Hematopoietic progenitors that undergo slow cell cycling were also observed in the hepatic sinusoids. This study clarifies the rate of production of mature and immature erythrocytes per day in the liver of X. laevis and the way that these cell numbers change in response to anemia.