PubMed Health⌕ Search

Biomedical subjects

T Mizutani

Publications and source records attributed to T Mizutani.

At least 19 recordsLinked to original sources
PubMed1992

The 5' untranslated region of the human cellular glutathione peroxidase gene is indispensable for its expression in COS-7 cells.

We studied the expression of the human cellular glutathione peroxidase (GPx) gene, from which a key enzyme containing selenocysteine (Scy) at the active site is produced. Expression of some human GPx gene mutants in COS-7 cells revealed that the 5' untranslated region (utr) was necessary for expression of the GPx gene, since mutant genes having 10 base pairs (bps) at the 5'utr (the complete had 311 bps) expressed GPx at very low levels. The genes with 311 or 408 bps at the 5'utr were better expressed than those having 257 bps. The GPx gene having 133 bps at the 3'utr (80 bps shorter than the entire length) was highly expressed. This deletion did not influence expression. We constructed some mutants in which 3 bases were altered at the upstream region of the Scy UGA codon in the frame of the GPx gene, by site-directed mutagenesis. GPx expression decreased but the expression was restored. Therefore, the upstream region of the in-frame Scy codon was not essential in the Scy decoding mechanisms. Finally, the 5'utr was essential for the expression of GPx gene. However, the deletion of a part of the 3'utr and the site-directed mutation upstream of the Scy codon did not show drastic effects on the expression.

Amino Acid Sequence↗
PubMed1992

Phosphorylation of chicken oviduct progesterone receptor by cAMP-dependent protein kinase.

Phosphorylation of immunopurified chicken oviduct progesterone receptor (PR) was studied in intact cells and under cell-free conditions. Cytosol PR was isolated by incubation with anti-PR monoclonal antibody alpha PR22 adsorbed to protein A-Sepharose and suspended in a reaction mixture containing 10 mM Mg2+, 0.1 mM [gamma-32P]ATP, and the catalytic subunit of cAMP-dependent protein kinase (cAMP-PK) from bovine heart. All three major proteins of avian PR (PR-A, 79 kDa; PR-B, 110 kDa; 90 kDa) incorporated 32P-radioactivity on serine residues. The phosphorylation reaction was inhibited by synthetic inhibitors of protein kinases, H-8 and 20-residue peptide IP20. A 40 degrees C preexposure of PR oligomer increased phosphorylation of the 90-kDa protein, known to be a heat-shock protein (hsp-90). The extent of the phosphorylation reaction was temperature-dependent as the 32P-incorporation into PR-A and PR-B increased gradually, showing a maximum at 37 degrees C. Multiple phosphopeptides (4-7) were resolved by two-dimensional electrophoresis chromatography following cleavage of 32P-labeled peptides with trypsin. Both A and B forms of receptor showed similar phosphorylation patterns with B receptor digestion exhibiting two to three additional peptides. Under physiological conditions, preincubation of oviduct mince with forskolin, a regulator of intracellular cAMP levels, caused a greater extent of phosphorylation of PR-A and PR-B proteins. The results of this study demonstrate that chicken oviduct PR is an excellent substrate for the action of cAMP-PK in vitro and that this enzyme may be a physiological regulator of progesterone action in the oviduct.

Adenosine Triphosphate↗
PubMed1992

Some properties of murine selenocysteine synthase.

Selenocysteine (Scy) was synthesized on natural opal suppressor tRNA(Ser) by conversion from seryl-tRNA. We studied the mechanisms of the synthesis of mammalian Scy-tRNA using hydro[75Se]selenide (H75Se-). We found Scy synthase activity in the 105,000 g supernatant of a murine liver extract. The supernatant was chromatographed on DEAE-cellulose, and the activity was eluted at 0.12 M-KCl. The reaction mixture for synthesis of Scy-tRNA contained suppressor tRNA, serine, ATP, seryl-tRNA synthetase (SerRS), HSe- and the enzyme to synthesize Scy-tRNA. These are all essential for the synthesis of Scy-tRNA. Scy in the tRNA product was confirmed by five t.l.c. systems. The conversion from seryl-tRNA to Scy-tRNA was also confirmed with the use of [14C]- and [3H]-serine. The apparent Km values for the substrates serine, tRNA, ATP and HSe- were 30 microM, 140 nM, 2 mM and 40 nM respectively. The active eluates from DEAE-cellulose contained no tRNA kinase. This result showed that Scy-tRNA was not synthesized through phosphoseryl-tRNA. ATP was necessary when Scy-tRNA was synthesized from seryl-tRNA and HSe-. Therefore ATP is used for not only the synthesis of seryl-tRNA but also for the synthesis of Scy-tRNA from seryl-tRNA. The active fraction from DEAE-cellulose was chromatographed on Sephacryl S-300, but the activity disappeared. However, the activity was recovered by mixing the eluates corresponding to proteins of 500 kDa and 20 kDa. In order to examine the binding of HSe- to proteins, a mixture of the active fraction, H75Se- and ATP was analysed by chromatography on Sephacryl S-300. The 75Se radioactivity was found at the position of a 20 kDa protein in the presence of ATP. Thus the 20 kDa protein plays a role in binding HSe- in the presence of ATP. The 500 kDa protein must have a role in the synthesis of Scy-tRNA. There are two natural suppressor serine tRNAs, tRNA(NCA) and tRNA(CmCA), in cell cytosol. The present paper shows that the suppressor tRNA fraction, eluted later on benzoylated DEAE-(BD-)cellulose, is a better substrate with which to synthesize Scy-tRNA. Thus we consider that murine Scy-tRNA is synthesized from a suppressor seryl-tRNA on the 500 kDa protein with the activated HSe-, which is synthesized with ATP on the 20 kDa protein. This mammalian mechanism used to synthesize Scy is similar to that seen in Escherichia coli.

Animals↗
PubMed1992

Amyotrophic lateral sclerosis with ophthalmoplegia and multisystem degeneration in patients on long-term use of respirators.

We describe two patients with sporadic amyotrophic lateral sclerosis (ALS), who had developed progressive external ophthalmoplegia of a predominantly supranuclear type while they survived on respirators, and displayed histopathological abnormalities both typical and atypical of ALS. Patient 1 was a 43-year-old man with ALS of 5-year duration, who had initially exhibited fulminant ALS, and remained on a respirator for 4 years. Patient 2 was a 51-year-old man with ALS of 13-year duration, who remained on a respirator for 8 years. Both patients died in a "totally locked-in state". Autopsy of both patients revealed not only histopathological abnormalities consistent with ALS, but also multisystem degeneration which involved the pontine tegmentum, substantia nigra, Clarke's dorsal nuclei and spinocerebellar tracts. In addition, Patient 2 displayed intracytoplasmic neuronal basophilic inclusion bodies which exhibited marked immunoreactivity to anti-ubiquitin antibodies. Our case reports indicate that the longer survival which is possible through the use of respirators may make one subgroup of ALS patients prone to develop atypical clinical and neuropathological features which are not observed during the natural course of ALS.

Adult↗
PubMed1992

Gerstmann-Sträussler syndrome--a variant type: amyloid plaques and Alzheimer's neurofibrillary tangles in cerebral cortex.

This report presents a variant of Gerstmann-Sträussler syndrome (GSS). A 53-year-old female had developed slowly progressive dementia and atactic gait since the age of 45. No myoclonic jerks and periodic synchronous discharges were observed throughout the illness. The neuropathological study revealed that many amyloid plaques and widespread Alzheimer's neurofibrillary tangles (NFTs) appeared in the cerebral cortex. Characteristically, the plaques reacted with anti-prion protein and none of them reacted with anti-beta protein, and they were made of many components, including amyloid cores, macrophages laden with lipid granules and/or degenerated neurites. Neuropil threads were seen mainly in amyloid plaques. Moreover, plaques appeared which were confluent and laminar in arrangement in the fifth and sixth cortical layers and had a close relationship to the neuronal loss. There was no spongiform change in the cerebral cortex or cerebellum. The cerebellum was almost intact except for a few amyloid plaques. Ultrastructurally, some of the plaques simulated kuru plaques and others had many degenerated neurites possessing paired helical filaments and other accumulated organelles. GSS has been proposed to include cases with progressive ataxia, dementia and massive multifocal plaques in the brain with or without cerebral spongiform changes. The case presented here is a very peculiar case of GSS. Recently, similar cases have been reported in some large families, diagnosed as familial Alzheimer's disease. These cases may be a telencephalic form with numerous NFTs of GSS.

Alzheimer Disease↗
PubMed1992

Dementia in cerebral amyloid angiopathy: a clinicopathological study.

Dementia is in addition to cerebral haemorrhage major symptom of cerebral amyloid angiopathy (CAa). In order to explore the pathological basis for dementia in CAa-related conditions, we made a clinicopathological analysis of CAa, with special attention to dementia. Among 150 patients (mean age 78.6 years) with autopsy-proven intracranial haemorrhage in Tokyo Metropolitan Geriatric Medical Center, CAa with cerebral haemorrhage accounted for 8.0% (12 cases), associated with hypertension and metastatic brain tumour. Among 38 patients with lobar haemorrhage, CAa represented the second most common cause (21.1%) of intracranial haemorrhage after hypertension. A total of 20 patients with CAa (mean age 82.5 years) were studies clinically and pathologically. Hypertension was present in 50%. Thirteen had a history of stroke and others had either ill-defined or no strokes. The average number of strokes 2.9. Fifteen patients (75%) had dementia. Based on the clinicopathological grounds for dementia, CAa-related conditions could be divided into three subtypes: "haemorrhagic", "dementia-haemorrhagic" and "dementia" type. Haemorrhagic type (30%, 6 cases) showed multiple recurrent lobar haemorrhages caused by CAa. Hypertension was present in only 1 patient. The incidence of senile plaques and neurofibrillary tangles was generally correlated with age. Only 1 patient had dementia. The dementia-haemorrhagic type (40%, 8 patients) had recurrent strokes with cerebral haemorrhage after preceding dementia. There were two different neuropathological subsets: CAa with atypical senile dementia of Alzheimer type (SDAT) and CAa with diffuse leucoencephalopathy. Patients with CAa with atypical SDAT had multiple cerebral haemorrhages caused by CAa combined with atypical Alzheimer-type pathology. Patients with CAa with diffuse leucoencephalopathy had cerebral haemorrhages in combination with diffuse white matter damage like Binswanger's subcortical vascular encephalopathy (BSVE). The incidence of senile changes correlated with age. Patients with the dementia type (30%, 6 patients) showed progressive dementia with or without haemorrhage. All had hypertension. They had a combined condition of Alzheimer-type pathology with conspicuous CAa with BSVE. Dementia in CAa-related conditions may be responsible for multiple factors including not Alzheimer-type degeneration, but also diffuse leucoencephalopathy like Binswanger's disease. We also found an asymptomatic type, an ischaemic type, a vasculitis type and an hereditary type in this condition.

Aged↗
PubMed1992

Peculiar axonal debris with subsequent astrocytic response (foamy spheroid body). A topographic, light microscopic, immunohistochemical and electron microscopic study.

Foamy spheroid bodies (FSBs) are described, as newly identified pathological structures occurring in human brain. FSBs favoured the substantia nigra pars reticulata (SNPR) and/or globus pallidus (GP) in degenerative conditions especially postencephalitic parkinsonism, progressive supranuclear palsy, pallido-nigro-luysial atrophy and multiple system atrophy. No FSBs were observed anywhere in the presence of substantia nigra pars compacta (SNPC) degeneration, such as occurs in idiopathic Parkinson's disease, or luysio-pallidal system degeneration, such as found in dentato-rubro-pallido-luysial atrophy or Joseph's disease. FSBs were also occasionally identified in the substantia nigra (SN) and/or GP of aged persons. In addition to SN and GP lesions, FSBs were seen in diffuse axonal lesions of long fibre tracts (the corpus callosum, the superior cerebellar peduncle) after non-missile head injuries, and in peri-infarct lesions. Under the light microscope, FSBs appear as slightly eosinophilic, foamy and nearly round objects with vague outlines, measuring approximately 10-50 microns in diameter. Some FSBs contain coarse, eosinophilic clusters at their periphery. FSB stained black when stained by the Gallyas silver method. Some FSBs were immunohistochemically positive for synaptophysin and 68 kDa neurofilament. Glial fibrillary acidic protein-positive fibres were observed alongside and/or inside some FSBs. Electron microscopically, FSBs were found to consist of collections of neuritic debris containing a variety of dense bodies and a small number of both mitochondria and neurofilaments. Some such collections were surrounded by astrocytic processes. These findings strongly suggest that FSBs are collections of small axonal debris destined for removal by astrocytes in due course. A variety of factors (degeneration of the SNPR and/or the GP, injury, infarction, ageing) seemed to be responsible for the histogenesis of FSBs.

Adult↗
PubMed1992

Correlation between epidermal growth factor receptor concentration and the growth of human gastric cancer xenografts in nude mice.

Seven human gastric cancer xenografts with different concentrations of EGF receptor were established in nude mice. The expression of EGF receptor in the tumors was demonstrated by Western blotting with anti-EGF receptor antibody, binding assay with 125I-EGF and immunohistochemistry with anti-EGF receptor antibody. Western blotting revealed EGF receptor doublet bands at molecular masses of 150 KDa and 170 KDa in all of the samples. The concentration of 125I-EGF binding activity in the tumors ranged from 36.0 to 11,000 fmol/mg protein, with a mean of 345 fmol/mg protein. EGF receptor was also demonstrated immunohistochemically on the apical border of the glands and the cell membrane of the tumor cells. There seemed to be a close correlation between the concentration of 125I-EGF binding activity and the doubling time of these tumors in nude mice (gamma = -0.68). However, no definite correlation was observed between EGF ligand binding and histological features of intestinal type or diffuse type. The expression of EGF receptor appears to facilitate the growth of human gastric cancer xenografts in nude mice.

Animals↗
PubMed1992

Neuropathological background of twenty-seven centenarian brains.

The neuropathological features of 27 centenarian brains were investigated. They were found to have no fundamental differences from the brains of younger elderly individuals. It was noted that 3 centenarian brains showed no apparent senile changes or ischemic lesions and this group was designated "supernormal" centenarians. In contrast, there were 6 centenarian brains with numerous senile plaques in the cerebral cortex, a finding resembling that seen in senile dementia of the Alzheimer type (SDAT). However, these brains had only a few neurofibrillary tangles mainly in the hippocampus and the medial temporal lobe, and therefore were not affected by SDAT. These subjects were not truly demented. It was considered that these brains showed the upper limit of normal ageing, while the "supernormal" centenarians showed the lower limit. In addition, idiopathic Parkinson's disease was diagnosed pathologically in 4 subjects who did not show any clinical symptoms of this disease. Finally, 2 out of 5 cases with dementia developed it secondary to subdural haematoma.

Aged↗
PubMed1992

Sex difference in the nephrotoxicity of thiabendazole in mice depleted of glutathione by treatment with DL-buthionine sulphoximine.

In ICR mice depleted of glutathione (GSH) by treatment with DL-buthionine sulphoximine (BSO), males were much more susceptible to thiabendazole (TBZ) nephrotoxicity than females. The nephrotoxicity was indicated by increases in relative kidney weight and serum urea nitrogen (SUN) concentration and by a decrease in renal GSH concentration at 24 hr after TBZ administration. The susceptibility of males to TBZ-induced nephrotoxicity was completely eliminated by pretreatment with oestradiol (OD). Castration of male mice also reduced, though not completely, their susceptibility to TBZ nephrotoxicity. In females pretreated with testosterone (TS), the nephrotoxic effect of TBZ was increased to an extent comparable with that in males.

Animals↗
PubMed1992

Novel antiprogestins Org 31806 and 31710: interaction with mammalian progesterone receptor and DNA binding of antisteroid receptor complexes.

We have examined steroid binding parameters and transformation of calf uterine progesterone receptor (PR) liganded with progestins (progesterone and R5020) and the newly synthesized antiprogestins (Org 31806 and 31710). Species specificity analysis indicated that [3H]R5020 binding in the chicken oviduct cytosol could be eliminated in the presence of 100-fold excess radioinert progesterone and R5020 but not Org 31806 and 31710. In the calf uterine cytosol, the progestins and the antiprogestins appeared to interact with the same PR as revealed by the displacement of [3H]R5020 by all of the above steroids. When the extent of [3H]R5020 binding was examined in the presence of different concentrations of radioinert steroids, the relative affinity with which these compounds interacted with the uterine PR was found to be comparable. A 23 degrees C incubation of cytosol transformed the progestin-bound PR complexes increasing their binding to DNA-cellulose from 5 (0 degrees C, nontransformed) to 35%. Under these conditions, 20% Org 31710- and RU486-occupied PR complexes bound to DNA-cellulose whereas only 10% Org 31806-receptor complexes were retained by the resin. Transformation (23 degrees C) of cytosol receptor caused a loss of the larger 8 S form and an increase in the smaller 4 S form. In its unliganded state or when it was complexed with R5020 or the antiprogestins, incubation of PR at 23 degrees C led to dissociation of the receptor-associated 90 kDa heat-shock protein (hsp90). The PR-hsp90 association was stabilized in the presence of 10 mM iodoacetamide when the ligand binding site was occupied by Org 31806 and 31710. The R5020-receptor complexes, however, allowed release of hsp90 under the above transforming conditions. Our results indicate that although Org 31806 and 31710 show no affinity for the avian PR, these steroids interact with the mammalian PR. We propose that the reported antiprogestational effects of Org 31806 and 31710 are mediated via their interaction with PR which appears similar to one that exists between PR and RU486.

Animals↗
PubMed1992

Anatomical study of the root apex in the maxillary anterior teeth.

The purpose of this study was to investigate anatomically the apical portion of the root canal of human maxillary anterior teeth. Thirty maxillary central incisors, 30 maxillary lateral incisors, and 30 maxillary cuspids were used. These were teeth from patients ranging in age from 11 to 73 yr. The root apex and main apical foramen coincided in 16.7% of central incisors and cuspids and in 6.7% of the lateral incisors. The labiolingual diameter of the root canal at the apical constriction of the central incisors, lateral incisors, and cuspids averaged 0.425 mm, 0.369 mm, and 0.375 mm, respectively; and the respective vertical distances between apex and apical constriction were 0.863 mm, 0.825 mm, and 1.010 mm.

Adolescent↗
PubMed1992

Palindromic morphea: multiple recurrence of morphea lesions in a case of systemic sclerosis.

We report an unusual scleroderma case. A 45-year-old woman had recurrent morphea lesions over 10 times in 6 years. She had had preceding inactive systemic scleroderma. New morphea lesions developed cyclically on various portions of her body and improved within 2 years. Interestingly, new lesions have developed on once involved skin as well as uninvolved skin. No exacerbation of systemic scleroderma was induced by outbreaks of new morphea lesions. We could not find a similar case in the literature and named it "Palindromic morphea" because of its unique clinical course. D-penicillamine treatment had a limited effect. Minimal oral prednisolone (5 mg/day) completely suppressed the multiple recurrence of the morphea lesions and enhanced improvement of the sclerosis.

Female↗
PubMed1992

Analysis by step sectioning of early invasive bladder cancer with special reference to G3.pT1 disease.

Eighty cases of cystectomized and step-sectioned pT1 transitional cell carcinomas of various grades were analyzed. During the same period, 30 consecutive cases of pT2 carcinomas were also cystectomized and examined for comparison. This is a cross-sectional study of a variety of cases of bladder cancer, designed to delineate the characteristics of G3.pT1 disease. Tumors in this series had a full set of various pathological findings; grades 1 to 3, stages Ta-T1-T2, papillary-papillonodular-nodular tumor configuration, alpha-beta-gamma type of invasion, presence of lymphatic and venous involvement, and presence of associated carcinoma in situ/dysplasia. There is a distinct tendency of stepwise disease progression, such as grade 1-->3, stage T1-->T2, papillary-->nodular configuration, and alpha-->gamma invasion, these factors being mutually related. We noted a similarity between tumor groups containing G3 component, such as G2-3.pT1, G3 > 2.pT1, G3.pT1, G1-3.pT2, and G3.pT2. These tumors are different from groups such as G1-2.pT1, G2.pT1 and G2 > 3.pT1 in terms of tumor configuration and type of invasion. As regards pT1 having G3 components, early cystectomy seems to be the surest treatment. Whenever one adopts a conservative policy in treatment of these tumors, extreme care should be taken to monitor tumor progression.

Adult↗
PubMed1992

Unilateral brain damage after prolonged hemiconvulsions in the elderly associated with theophylline administration.

The brains of 14 elderly patients who died after status epilepticus were examined pathologically. Three of the 14 patients showed unilateral brain damage which corresponded to the side of the seizures, and the lesions were thought to be caused by seizures. In these three and two other patients, no causative lesion related to the seizures was found. In these five patients, status epilepticus occurred during theophylline therapy and thus the seizures in these five patients were assumed to be induced by theophylline. In the three patients with unilateral brain damage, the damage was seen in the hippocampus, amygdala and thalamus in two patients, while in the third, the whole hemisphere was damaged, including the hippocampus, amygdala, thalamus, basal ganglia and cerebral cortex. The distribution of pathological changes within the thalamus was described. It is suggested that the thalamus was primarily affected by seizures, rather than by secondary degeneration from the cortex.

Aged↗
PubMed1992

Efficacy of whole bowel irrigation using solutions with or without adsorbent in the removal of paraquat in dogs.

1. The efficacy of whole bowel irrigation with a solution containing either polyethylene glycol (PEG) with electrolyte or an adsorbent (Kayexalate with a cathartic (sorbitol) was investigated in 18 dogs who had been given 250 mg kg-1 paraquat dichloride via a jejunal tube to eliminate the influence of gastric absorption. 2. Plasma paraquat concentrations 2 and 3 h after the initiation of bowel irrigation and at the end of the study (5 h later) were significantly lower in the bowel irrigation groups than in the control (no bowel irrigation) group. 3. The total body clearances of paraquat in the bowel irrigation groups were significantly greater than in the control group. 4. There were no significant differences between the two different irrigation solution groups in plasma paraquat concentration, the area under the plasma concentration time curve and the total body clearance. 5. In the PEG with electrolyte group, about 70% of the administered dose of paraquat was removed by means of bowel irrigation (n = 4). 6. The adjunction of the adsorbent had no beneficial effects. 7. Haemodynamic changes associated with whole bowel irrigation were unremarkable except that right atrial and pulmonary arterial pressures were elevated in the latter part of the study.

Animals↗