Genetic analysis of the glucose-6-phosphatase mutation of type la glycogen storage disease in a Chinese family

Type la glycogen storage disease (GSD) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (GóPase). Polymerase chain reaction (PCR) and nucleotide sequence analysis were used to identify the location and nature of mutations at the GóPase locus in two siblings affected with type la GSD. Both patients are compound heterozygotes with two different single nucleotide substitutions in the two GóPase alleles. A guanine to adenine transition was identified at base position 327 in the exon 2, converting an arginine to a histidine at codon 83. The second substitution was a thymine to adenine transversion at base position 1101 in the exon 5, converting an isoleucine to an asparagine at codon 341. Family study reveals that both parents are heterozygous carriers: the father with a mutant GóPase allele at exon 2, the mother with another mutant GóPase allele at exon 5. This is the first family study in Taiwan on type la GSD identified by molecular analysis. The mutations identified herein are novel substitutions in the GóPase gene. In addition, an adenine to guanine substitution was observed at base position 653 in the exon 5 of GóPase gene in both sibling patients and their parents, as well as in 15 normal Chinese subjects and three normal Caucasian subjects.     

Intracellular ion exchange between cytoplasmic potassium and granule histamine,an integrated link in the histamine release machinery of mast cells*

Rat peritoneal mast cells isolated by gradient centrifugation in Percoll were placed between two membrane filters in a Sartorius filter apparatus and superfused with isotonic balanced salt solutions or with deionized isotonic sucrose. Histamine was released according to ion exchange kinetics. Our explanation of the observed phenomena is as follows. The superfusion induces a flow of cytoplasmic K⁺ ions across the histamine-containing granules, resulting in an ion exchange K⁺←Hi⁺ ions at the histamine binding sites. The concomitant equimolar outflow of histamine and potassium is considered to be due to a functional interplay between two histamine pools, a release and a donor pool. As the result of the K⁺←SHi⁺ ion exchange at the histamine binding sites of the release pool, these sites become transiently occupied by K⁺ ions only to be immediately reoccupied by Hi⁺ ions from the donor pool. The observed equimolar outflows are consistent with a 1/1 molar ratio in the exchange between histamine and potassium ions. The essential role of cytoplasmic potassium in the histamine release mechanism is a new and important observation with possible implications not only as to histamine release in general (including so-called ‘spontaneous’ histamine release) but also as to the release of biogenic amines and other positively charged substances stored in granules in ionic linkage to the matrix.     

Classification and genetic features of neonatal haemochromatosis: a study of 27 affected pedigrees and molecular analysis of genes implicated in iron metabolism

Neonatal haemochromatosis (NH) is a severe and newly recognised syndrome of uncertain aetiology, characterised by congenital cirrhosis or fulminant hepatitis and widespread tissue iron deposition. NH occurs in the context of maternal disease including viral infection, as a complication of metabolic disease in the fetus, and sporadically or recurrently, without overt cause, in sibs. Although an underlying genetic basis for NH has been suspected, no test is available for predictive analysis in at risk pregnancies.
  As a first step towards an understanding of the putative genetic basis for neonatal haemochromatosis, we have conducted a systematic study of the mode of transmission of this disorder in a total of 40 infants born to 27 families. We have moreover carried out a molecular analysis of candidate genes (β₂-microglobulin, HFE, and haem oxygenases 1 and 2) implicated in iron metabolism. No pathogenic mutations in these genes were identified that segregate consistently with the disease phenotype in multiplex pedigrees. However, excluding four pedigrees with clear evidence of maternal infection associated with NH, a pedigree showing transmission of maternal antinuclear factor and ribonucleoprotein antibodies to the affected infants, and two families with possible matrilineal inheritance of disease in maternal half sibs, a large subgroup of the affected pedigrees point to the inheritance of an autosomal recessive trait. This included 14 pedigrees with affected and unaffected infants and a single pedigree where all four affected infants were the sole offspring of consanguineous but otherwise healthy parents.
  We thus report three distinct patterns of disease transmission in neonatal haemochromatosis. In the differentiation of a large subgroup showing transmission of disease in a manner suggesting autosomal recessive inheritance, we also provide the basis for further genome wide studies to define chromosomal determinants of iron storage disease in the newborn.


Keywords: iron storage; haemochromatosis; neonatal; liver     

Spatial orientation of optokinetic nystagmus and ocular pursuit during orbital space flight

On Earth, eye velocity of horizontal optokinetic nystagmus (OKN) orients to gravito-inertial acceleration (GIA), the sum of linear accelerations acting on the head and body. We determined whether adaptation to microgravity altered this orientation and whether ocular pursuit exhibited similar properties. Eye movements of four astronauts were recorded with three-dimensional video-oculography. Optokinetic stimuli were stripes moving horizontally, vertically, and obliquely at 30°/s. Ocular pursuit was produced by a spot moving horizontally or vertically at 20°/s. Subjects were either stationary or were centrifuged during OKN with 1 or 0.5 g of interaural or dorsoventral centripetal linear acceleration. Average eye position during OKN (the beating field) moved into the quick-phase direction by 10° during lateral and upward field movement in all conditions. The beating field did not shift up during downward OKN on Earth, but there was a strong upward movement of the beating field (9°) during downward OKN in the absence of gravity; this likely represents an adaptation to the lack of a vertical 1-g bias in-flight. The horizontal OKN velocity axis tilted 9° in the roll plane toward the GIA during interaural centrifugation, both on Earth and in space. During oblique OKN, the velocity vector tilted towards the GIA in the roll plane when there was a disparity between the direction of stripe motion and the GIA, but not when the two were aligned. In contrast, dorsoventral acceleration tilted the horizontal OKN velocity vector 6° in pitch away from the GIA. Roll tilts of the horizontal OKN velocity vector toward the GIA during interaural centrifugation are consistent with the orientation properties of velocity storage, but pitch tilts away from the GIA when centrifuged while supine are not. We speculate that visual suppression during OKN may have caused the velocity vector to tilt away from the GIA during dorsoventral centrifugation. Vertical OKN and ocular pursuit did not exhibit orientation toward the GIA in any condition. Static full-body roll tilts and centrifugation generating an equivalent interaural acceleration produced the same tilts in the horizontal OKN velocity before and after flight. Thus, the magnitude of tilt in OKN velocity was dependent on the magnitude of interaural linear acceleration, rather than the tilt of the GIA with regard to the head. These results favor a filter model of spatial orientation in which orienting eye movements are proportional to the magnitude of low frequency interaural linear acceleration, rather than models that postulate an internal representation of gravity as the basis for spatial orientation.Abbreviations A_g Acceleration of gravity - A_c Centripetal acceleration - CCW Counterclockwise - CW Clockwise - FD- X Flight day X - g Gravity - GIA Gravito-inertial acceleration - H Horizontal - LED Left-ear-down - LEO Left-ear-out - LOB Lying-on-back - L- X Launch minus X days - NCM No-chair-motion - ND Nose-down - NU Nose-up - OCR Ocular counter-colling - OKAN Optokinetic after-nystagmus - OKN Optokinetic nystagmus - OKS Optokinetic stimulus - pos Position - REO Right-ear-out - R+ X Recovery plus X days - T Torsional - V Vertical - vel Velocity     

Effects of prolonged weightlessness on horizontal and vertical optokinetic nystagmus and optokinetic after-nystagmus in humans

Horizontal and vertical optokinetic nystagmus (OKN) and optokinetic after-nystagmus (OKAN) provided by a partial-field, binocular optokinetic stimulator were recorded in one astronaut before, during, and after a 25-day space flight. A ground-based study was performed on six control subjects. During the flight experiment, performed on flight days 5, 18, 19, and 21, the subject either had their feet attached to the deck or was free-floating. Vertical OKN gain only slightly increased in weightlessness compared with ground data, but the center of interest (CI) during vertical OKN, evaluated by the eye position in the saggital plane at the end of the fast phases relative to the straight-ahead direction, was found to be significantly changed during long-term exposure to weightlessness. The horizontal CI showed very little change in-flight, but the gain was increased. The time constant for the astronaut was small for vertical OKAN, but there was an increase in slow-phase velocity (SPV) by the end of the flight, which returned to normal postflight. These results partly confirm the data obtained during head-tilt studies on the ground and are in accordance with the hypothesis of a gravity-dependent control of vertical gaze direction during orientation reflexes.     

Km mutant of acid α-glucosidase in a case of cardiomyopathy without signs of skeletal muscle involvement

A male patient is reported with a mutation of acid alpha-glucosidase causing an altered Km toward natural substrates. Cardiac arrhythmia was found at 12 years of age, and he died of heart failure at 15 years. No skeletal muscle involvement was observed either clinically or histologically. Acid alpha-glucosidase activity in fibroblasts was moderately low (43% of the control mean) with normal Km for 4-methylumbelliferyl alpha-D-glucoside. The hydrolysis of glycogen was markedly decreased (14% of the control mean), and the Km for maltose was increased 4-fold and for glycogen 5-fold. The biosynthesis and the posttranslational processing of the mutant enzyme appeared normal, but the total amount of the enzyme was lower than normal. This mutant enzyme comigrated with normal acid alpha-glucosidase on starch gel electrophoresis, and not with the rare isozyme, acid alpha-glucosidase 2. A possible role of this mutant enzyme in the pathogenesis of this disease and the relationship to glycogenesis II are discussed.     

黄瓜保鲜技术研究及应用

目的：延长黄瓜在南海海区常温条件下的贮藏期,解决执行长航任务的舰艇部队吃鲜菜难问题。方法：在南海常温条件下（26-37℃）应用该所研制的HY-1型和HY-2型保鲜剂、保鲜箱对黄瓜进行保鲜贮藏。结果：经实验室和南海海区多次实验证实,经保鲜处理的黄瓜可延长贮藏期8-10d,腐烂率控制在10%以下,结论：该技术能延长黄瓜的贮藏期,可推广应用。     

Guía práctica para el uso de registros visuales en la era del Reglamento General de Protección de Datos de la Unión Europea

With the European Union's new General Data Protection Regulation, commonly known as “GDPR”, as the new framework for data protection across the European Union, doctors will need to review how they collect and share personal data to ensure they meet the standards.The aim of this article is to raise awareness on the General Data Protection Regulation, and to provide an easy guideline to steer free from legal problems at the time of drafting papers, presenting lectures and sharing personal data and visual media in particular.To do so, we have analysed the most common situations where personal data, and above all visual media, can be collected, giving clear-cut answers and recommendations for all the scenarios.     

A T > C transition causing a Leu > Pro substitution in a conserved region of the arylsulfatase A gene in a late infantile metachromatic leukodystrophy patient

A T >C transition (L428P) was detected in the arylsulfatase A alleles of a late infantile metachromatic leukodystrophy patient. The mutation causes a Leu > Pro substitution in exon 8. It lies in a region conserved among arylsulfatases. The mutation was not detected in 37 other patients and in 57 normal controls.     

Glucose-6-phosphatase gene (727G→T) splicing mutation is prevalent in Hong Kong Chinese patients with glycogen storage disease type la

Glycogen storage disease type la (GSD1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (GóPase). We analyzed the GóPase genes of two unrelated Chinese families with GSD1a. DNA sequencing of all five exons and the exonintron boundaries revealed a G → T transversion at nucleotide 727 (727G→T) in exon 5, which has previously been reported to cause abnormal splicing. In one family, the subject and her affected sister were confirmed to be homozygous for this mutation and their parents to be heterozygotes. In the other family, the proband was identified to be heterozygous for this mutation, and a novel mutation, the 341delG in exon 2, was identified. This mutation alters the reading frame and creates a stop codon TAA 15 codons downstream from the mutation, resulting in a truncated protein. Family studies revealed that the father was heterozygous for the 727G → T mutation and that the mother was heterozygous for the 341delG mutation. This is the first time that the 727G→T mutation has been found in Chinese patients or outside Japan. Since we only tested two GSDla families and found 727G→T in both, we believe that this mutation may also be prevalent in our local Chinese population. To investigate allele frequencies, we screened 385 Chinese healthy volunteers and found two asymptomatic carriers. Our findings suggest that the 727G → T mutation is indeed prevalent in Hong Kong.