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Biomedical subjects

T Anezaki

Publications and source records attributed to T Anezaki.

12 recordsLinked to original sources

Haplotype and mutation analysis in Japanese patients with Wilson disease.

Wilson disease (WD), an autosomal recessive disorder of copper transport, is characterized by impaired biliary excretion and by impaired incorporation of copper into ceruloplasmin. Toxic accumulation of copper causes tissue damage, primarily in the liver, brain, and kidneys. The gene for WD (ATP7B) has been cloned, and the protein product is predicted to be a copper-transporting P-type ATPase with high amino acid identity with that for Menkes disease, an X-linked disorder of copper transport. Mutation screening in WD patients has led to the identification of at least 40 mutations. In addition, haplotype analysis using three dinucleotide-repeat markers, D13S314, D13S301, and D13S316, has been a useful indicator of specific mutations. We have determined haplotypes for the patients and their parents and sibs, in 21 unrelated WD families from Japan. Twenty-eight different haplotypes were observed on 42 WD chromosomes. In all the patients, the ATP7B coding sequence, including the intron-exon boundaries, was screened for mutations, by SSCP, followed by direct-sequence analysis of the shifted fragments. We identified 13 mutations, of which 11 mutations are novel, including 7 mutations-1 insertion, 4 deletions, and 2 missense mutations-in the coding region. The mutations reported in previous studies are 2299insC and Arg778Leu. Two patients were shown to have the 2299insC mutation, which has occurred in many different haplotypes in several populations, indicating a mutation hot spot. Primer-extension analysis of ATP7B mRNA has revealed multiple transcription start sites. Four of the novel mutations (three 1-bp changes and one 5-bp deletion) occur in the 5' UTR and may result in altered expression of the WD gene.

Adenosine Triphosphatases

Decrease in benzodiazepine receptor binding in a patient with Angelman syndrome detected by iodine-123 iomazenil and single-photon emission tomography.

A receptor mapping technique using iodine-123 iomazenil and single-photon emission tomography (SPET) was employed to examine benzodiazepine receptor binding in a patient with Angelman syndrome (AS). AS is characterized by developmental delay, seizures, inappropriate laughter and ataxic movement. In this entity there is a cytogenic deletion of the proximal long arm of chromosome 15q11-q13, where the gene encoding the GABAA receptor beta3 subunit (GABRB3) is located. Since the benzodiazepine receptor is constructed as a receptor-ionophore complex that contains the GABAA receptor, it is a suitable marker for GABA-ergic synapsis. To determine whether benzodiazepine receptor density, which indirectly indicates changes in GABAA receptor density, is altered in the brain in patients with AS, we investigated a 27-year-old woman with AS using 123I-iomazenil and SPET. Receptor density was quantitatively assessed by measuring the binding potential using a simplified method. Regional cerebral blood flow was also measured with N-isopropyl-p-[123I]iodoamphetamine. We demonstrated that benzodiazepine receptor density is severely decreased in the cerebellum, and mildly decreased in the frontal and temporal cortices and basal ganglia, a result which is considered to indicate decreased GABAA receptor density in these regions. Although the deletion of GABRB3 was not observed in the present study, we indirectly demonstrated the disturbance of inhibitory neurotransmission mediated by the GABAA receptor in the investigated patient. 123I-iomazenil with SPET was useful to map benzodiazepine receptors, which indicate GABAA receptor distribution and their density.

Adult

Changes of growth inhibitory factor after stab wounds in rat brain.

The growth inhibitory factor (GIF) is a new metallothionein (MT)-like protein that is downregulated in Alzheimer's disease (AD) brain. The biological function of GIF has not been fully clarified yet. We have raised an antibody to the synthetic polypeptide that is specific for rat GIF. The purified antibody reacted to recombinant GIF and native rat GIF but not to MT or maltose-binding protein. Using the antibody and GIF cDNA probe, we investigated changes of GIF and GIF mRNA by Western and Northern blotting techniques in rat brains after stab wounds. The levels of GIF and GIF mRNA began to increase 4 days postoperation, reached a maximum at 14-21 days and sustained the increased level at least through 28 days. While both glial fibrillary acidic protein (GFAP) and GIF were recognized in astrocytes, the increases of these 2 proteins after stab wounds showed different patterns. The results indicated that GIF could play an important role in the repair after brain damage and also produce new insights into the mechanism of gliosis investigated mainly from the viewpoint of GFAP.

Alzheimer Disease

Expression of growth inhibitory factor (GIF) in normal and injured rat brains.

Immunohistochemical study on growth inhibitory factor (GIF) in rat brain has revealed that a glial cell layer on the surface of cerebral cortex and the cells surrounding Purkinje cells has been reported. In addition, neurons in gray matter were weakly immunostained for GIF. In situ hybridization using digoxigenin-labeled single-strand RNA probes also demonstrated that most of the neurons and small round cells, which were presumably astrocytes, expressed GIF mRNA in the cerebral cortex of rat brain. These findings indicate that GIF is produced in neurons as well as in astrocytes. The most prominent findings in this study are, a very strong reaction of GIF and GIF mRNA in the reactive astrocytes around the site of injury induced by stab wound or kainic acid injection. These results raised the possibility that GIF may act as an acute-phase protein in reactive astrocytes and have a role in tissue repair.

Animals

[Familial myopathy associated with tubular aggregates--report of two siblings].

We reported two siblings with slowly progressive muscle weakness in proximal and peroneal muscles without atrophy, myalgia, cramps, or episodic weakness. The serum creatine kinase level was moderately elevated. The prominent features of their muscle pathology were accumulation of tubular aggregates in type 2 fibers, predominantly in type 2B fibers, and marked type 1 fiber atrophy. Three to eleven % of muscle fibers contained tubular aggregates. Electron microscopic examination revealed accumulation of double-walled tubular structures. Familial myopathy with tubular aggregates as a hallmark of muscle pathology is considered to be a new clinical form of childhood-onset familial myopathies.

Child

Remote astrocytic response of prefrontal cortex is caused by the lesions in the nucleus basalis of Meynert, but not in the ventral tegmental area.

The nucleus basalis of Meynert (nbM) was lesioned by injection of ibotenic acid, in 200 g male Wistar rats. The rats were killed 1, 3, 7 or 21 days after surgery, the brains were removed and the prefrontal cortices were subjected to immunohistochemical and Western blot analysis for the expression of glial fibrillary acidic protein (GFAP). In some rats, vehicle was injected into the nbM and in others 6-hydroxydopamine (6-OHDA) was injected into the ventral tegmental area (VTA). Quantitative Western blot analysis revealed significantly greater immunoreactivity for GFAP in the prefrontal cortex of nbM-lesioned rats. Immunohistochemical examination revealed fibrous and hypertrophic GFAP-positive astrocytes even one day after surgery, and this reaction was stronger at 3 days after surgery. After this peak, GFAP-immunoreactivity of the astrocytes decreased from 7 days to 21 days. In contrast, GFAP-positive astrocytes were not observed in the brains of vehicle-injected or VTA-lesioned rats, even 21 days after surgery. The present results indicate that cortical astrocytes respond to cholinergic deafferentation. In addition, our findings provide new insights into the abnormalities of cortical glial cells after cholinergic deafferentation in Alzheimer's disease.

Acetylcholine

A patient with severe iron-deficiency anemia and memory disturbance.

A 56-year-old woman presented with severe iron-deficiency anemia and memory disturbance. She had been in a state of severe iron deficiency for many years due to an unbalanced diet. Aerobic exercise test revealed an abnormal elevation of lactate and pyruvate reflecting mitochondrial dysfunction. After iron replacement therapy, WAIS verbal IQ score improved from 63 to 83, and levels of lactate and pyruvate on aerobic exercise test were normalized. We raise the possibility that severe and long-term iron deficiency anemia may cause memory disturbance due to mitochondrial dysfunction.

Anemia, Hypochromic

Morphometric studies on the rat liver in biliary obstruction.

The common bile ducts of the Wistar rats were ligated and severed, and liver biopsies were done weekly for 7 postoperative weeks. Light and electron microscopic specimens were prepared for the morphometric studies. The volume ratio of the hepatic parenchyma decline with the lapse of time after bile duct ligation. However, elevated mean sectional area of the nucleus, increased mitotic index and unchanged estimated weight of the hepatic parenchyma after biliary obstruction suggested that lost hepatocytes were compensated by regeneration. Mitochondrial swelling and curling of the cristae were noted in biliary obstruction in general. Moreover, both the number and volume ratio of the mitochondria were increased corresponding to the duration of biliary obstruction. These changes were interpreted as an adaptation process to mitochondrial dysfunction.

Animals

Biochemical study of fibrosis in the rat liver in biliary obstruction.

In an attempt to study the collagen formation in the liver occurring in association with obstructive jaundice, the authors carried out an experiment with liver slices from common bile duct-ligated rats. Hepatic collagen was fractionated into the neutral soluble, acid soluble and insoluble fractions, and the hydroxyproline synthesis rate of each fraction was measured using 14C-proline. Determination was also made for hexosamine content in the same liver tissue. The hydroxyproline content of hepatic collagen increased as biliary obstruction was prolonged, particularly from the 4th week, which is the transitional period of liver histology into biliary cirrhosis. The hexosamine content of hepatic collagen showed a similar tendency. The neutral soluble, acid soluble and insoluble collagen fractions all increased as biliary obstruction was prolonged. The collagenosynthetic activity of the neutral soluble fraction, attained a peak in 1 to 2 weeks of biliary obstruction, which indicates that collagen fibers are formed actively in the early stage of jaundice, although there is only a slight increase in the absolute amount of fibers developed then. Serum monoamine oxidase level tended to be parallel to collagenosynthetic activity but not to collagen content.

Animals