[The relation between physical status, life style and subjective feeling of health].
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Biomedical subjects
Publications and source records attributed to T Hashimoto.
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Twenty-seven children, who had deep white matter hyperintensity in the occipital lobe (DWMH) on T2-weighted MRI, were classified into two groups, mild and severe, based on the signal intensity. The frequency of mild DWMH, which was iso-or hyperintense relative to the gray matter but hypointense relative to cerebrospinal fluid (CSF), decreased with aging; mild DWMH might result from a delayed myelination in the central nervous system. However, the frequency of severe DWMH, which was iso-or hyperintense relative to CSF, was not related to aging and was significantly high in severely retarded children. Therefore, severe DWMH might be a new indicator of mental retardation in children.
To examine the function of the amino-terminal presequence of rat peroxisomal 3-ketoacyl-CoA thiolase precursor, fusion proteins of various amino-terminal regions of the precursor with non-peroxisomal enzymes were expressed in cultured mammalian cells. On immunofluorescence microscopy, all constructs carrying the presequence part exhibited punctate patterns of distribution, identical with that of catalase, a peroxisomal marker. Proteins lacking all or a part of the prepiece were found in the cytosol. These results indicate that the presequence of the thiolase has sufficient information for peroxisomal targeting.
To examine 3-ketothiolase deficiency at the gene level, we analyzed the structure of the human mitochondrial acetoacetyl-CoA thiolase (MAT; EC 2.3.1.9)-encoding gene (MAT). From the genomic library of a normal subject in lambda EMBL3, we isolated seven overlapping clones covering the entire length of MAT and the structural organization was determined. The gene spans approx. 27 kb and contains twelve exons interrupted by eleven introns. The 5'-flanking region of the gene lacks a conventional TATA box, but is G + C-rich and contains two CAAT boxes. Included are a putative binding site for the transcription factor, Sp1, and sequences resembling the binding sites of several other transcription factors, all features characteristic of housekeeping genes. A CAT assay revealed that a 101-bp DNA fragment immediately upstream from the cap site has promoter activity, and suggested that a DNA fragment from bp -888 to -102 probably contains a negative regulatory element(s).
The effect of continuous administration of 4-aminomethyl-1-benzylpyrrolidin-2-one-hemifumarate (WEB 1881 FU) on cerebral cholinergic neurons was studied using rats treated with ethylcholine aziridinium ion (AF64A), a neurotoxic choline analog. AF64A (2.0 nmol, administered i.c.v.) caused a significant decrease in the hippocampal acetylcholine (ACh) content. This decrease in hippocampal ACh content was accompanied by a reduction of choline acetyltransferase (CAT) activity. Under these experimental conditions, the latency of the passive avoidance response of rats, determined with a step-through method, was strongly decreased as compared with that of sham-operated rats. Although treatment with WEB 1881 FU (50 mg/kg per day, administered orally for 7 days) from immediately after the administration of AF64A did not affect the AF64A-induced decrease of ACh in the hippocampus, 100 mg/kg per day of WEB 1881 FU (orally for 7 days) significantly suppressed the AF64A-induced declines in hippocampal ACh content and CAT activity. The AF64A-induced reduction in latency of the passive avoidance response was also significantly antagonized by the treatment with 100 mg/kg per day of WEB 1881 FU (administered orally for 7 days) from immediately after the administration of AF64A. Continuous administration of WEB 1881 FU (100 mg/kg per day, orally for 7 days) from 7 days after the treatment with AF64A also had a significant inhibitory effect on the AF64A-induced decrease in ACh content in the hippocampus. These results suggest that WEB 1881 FU may have protective actions on the destruction of hippocampal cholingergic neurons as well as memory impairment induced by AF64A administration.
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To establish a tumor-node-metastasis (TNM) classification of thymoma, 207 thymoma patients seen at the First Department of Surgery, Osaka University, and the Second Department of Surgery, Nagoya City University, were evaluated. Lymphogenous and hematogenous metastases of thymoma were infrequent, but their frequency increased with the duration of the course. Lymphogenous metastasis was observed in few cases, but it was considered to progress from anterior mediastinal lymph nodes to intrathoracic and then to extrathoracic lymph nodes. No particular characteristics were observed in hematogenous metastasis. On the basis of these observations, a TNM classification of thymoma was established and applied it to 207 thymoma cases, but it had little advantage over conventional clinical staging. High percentages of thymic carcinomas and thymic carcinoids were in Stage IVB, and the TNM classification of these tumors was considered to be more useful.
The effect of treatment with thyrotropin-releasing hormone (TRH) or naloxone on the neurologic impairment after spinal cord injury was studied in rats with the severest neurologic impairment (complete paraplegia, no withdrawal response upon tail pinching, and urinary incontinence) 24 h and 7 days after injury. Subcutaneous treatment with TRH (2.5, 10 and 40 mg/kg per day) once daily for 7 consecutive days starting 24 h or 7 days after injury improved the neurologic function in the rats with cord injury in a dose-related manner, with a minimum effective dose of less than 2.5 mg/kg per day in both cases. However, subcutaneous treatment with naloxone (40 mg/kg per day) once daily for 7 consecutive days starting 24 h after injury did not exert any beneficial effects on neurologic function. These results indicate that TRH but not naloxone treatment starting 24 h and as late as 7 days after injury is effective in rats with the severest neurologic impairment following spinal cord injury. Thus, it is suggested that the duration of the effectiveness of late treatment with TRH on the neurologic impairment in rats with spinal cord injury is more than 1 week, while the duration with naloxone is less than 24 h.
The authors reviewed magnetic resonance (MR) images in seven cases of germinoma in the hypothalamoneurohypophyseal axis (HNA). The intrasellar portions were clearly identified in six germinomas. Two small germinomas of these six were located only in the neurohypophysis. The major parts of the four large germinomas were located below the optic chiasm, and the large intrasellar portions were demonstrated. The remaining one small germinoma was localized from the pituitary stalk to the third ventricular floor. These findings strongly suggest that the primary site of germinomas in the HNA is the neurohypophysis. In the four large germinomas, the tumor shape was similar to that of pituitary adenoma. The authors believe that age (limited to first three decades), symptoms (diabetes insipidus), MR findings (absence of normal hyperintense signal of the posterior pituitary on T1-weighted (T1WI) images, and homogeneous hypointensity to the pons on T1WI images/isointensity on T2-weighted images are important in differential diagnosis.
The molecular basis of 3-ketothiolase deficiency (3KTD) was examined in a 3KTD family. Immunochemical analyses showed that mitochondrial acetoacetyl-CoA thiolase (T2) biosynthesized in the patient's fibroblasts (GK06) was unstable and that the parents and brother were obligatory carriers of 3KTD. When sequencing the PCR-amplified patient's T2 cDNA, we noted a G to A replacement which caused 347Ala to Thr substitution of the mature T2 subunit. Transfection analysis revealed that this substitution resulted in an instability of the T2 protein. Analyses of the T2 cDNA and gene of the family indicated that the patient was a compound heterozygote; the allele that derived from the mother had a point mutation (347Ala to Thr) and the other allele from the father has a mutation which would abolish the T2 gene expression. This report is apparently the first definition of a mutant allele for 3KTD, at the gene level.
The immunohistochemical studies on a peroxisomal enzyme, catalase, were done on brains from human fetuses to adults. The catalase-positive neurons appeared in the basal ganglia, thalamus and cerebellum at 27-28 weeks of gestation, and in the frontal cortex at 35 weeks. They then increased in number with gestational age. The extent of immunopositive staining increased with enlargement of perikaryonal size. However, the extent gradually decreased with postnatal age. On the other hand, catalase-positive glia appeared in the deep white matter at 31-32 weeks of gestation, their appearance shifting from the deep to the superficial white matter with increasing age. These results suggest that peroxisomes are closely related to neuronal growth and myelinogenesis in the human brain during development.
Involvement of histamine H1 receptor in the brains of schizophrenic patients was investigated using 3H-mepyramine as a ligand. The specific 3H-mepyramine binding in the frontal cortex was saturable with the dissociation constant (Kd) of about 0.6 nM and the maximum number of binding sites (Bmax) of 64 fmol/mg protein. Specific H1 antagonists, mepyramine (Ki = 1.4 nM), promethazine (Ki = 1.4 nM), diphenylpyraline (Ki = 4.1 nM), triprolidine (Ki = 5.3 nM), diphenylhydramine (Ki = 35 nM), but not the specific H2 antagonist, cimetidine (Ki greater than 10(5) nM), strongly inhibited the 3H-mepyramine binding. Regional distribution of the specific 3H-mepyramine binding was in the order of: frontal cortex greater than hippocampus greater than cerebellum greater than hypothalamus greater than thalamus, putamen, and pallidum. The specific 3H-mepyramine binding in schizophrenic brains was reduced by 56% in the frontal cortex. Representative Scatchard analyses of the specific 3H-mepyramine binding revealed changes resulting from a decrease in receptor density but not in receptor affinity. Down-regulation of the histamine H1 receptor in the frontal cortex may be involved in the pathophysiology of schizophrenia.
Pig plasma gelsolin was modified with the fluorescent reagent 4-fluoro-7-nitrobenz-2-oxa-1,3-diazole (NBD-F) for lysyl residues. The relationship between the gelsolin activity and the degree of NBD labeling suggested that a single lysyl residue, which reacted five times slower than the other reactive lysyl residues, was essential for the activity. Taking advantage of the slow reactivity of the essential residue, active NBD-gelsolin was prepared. Limited cleavage of NBD-gelsolin by chymotrypsin indicated that the fluorescent reagents were randomly incorporated into all fragments observed. When NBD-gelsolin formed a gelsolin/actin (1:2) complex in the presence of micromolar Ca2+, the fluorescence spectra of NBD-gelsolin were red-shifted by 5 nm and the intensity decreased by 30%. However, on binding to phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), the fluorescence spectra were blue-shifted by 5 nm with a concomitant increase in intensity by 20%. The addition of PtdIns(4,5)P2 to the NBD-gelsolin actin (1:2) complex restored the fluorescence spectra to that obtained in the presence of PtdIns(4,5)P2 alone. These results indicated that NBD-gelsolin, selectively labeled on lysyl residues not essential for activity, can be a useful probe to monitor the binding of PtdIns(4,5)P2 and actin.
The product of the human retinoblastoma gene (RB) is a nuclear phosphoprotein that is thought to function as a tumor suppressor. Mutations of RB frequently occur in human bladder carcinoma. To investigate the significance of the functional loss of this gene in bladder cancer, an RB expression plasmid (pBARB) under control of the human beta-actin promoter was transfected into the bladder carcinoma cell line HTB9, which lacks RB expression. Marker-selected transfectants that expressed RB protein were identified by immunoblotting and immunohistochemical staining. In selected clones, stable RB expression has persisted over 1 yr under standard culture conditions with 10% serum. However, RB expression caused major alterations of HTB9 growth properties both in vitro and in vivo. RB+ transfectants lacked the ability to form colonies in semi-solid medium, and their growth rate was significantly decreased in 3% serum. In addition, the tumorigenicity of these transfectants was markedly decreased. Tumors that formed in nude mice were much smaller and had a longer latency period but were indistinguishable microscopically from those produced by parental cells. Slower growing tumors were RB+, as measured by nuclear staining of their RB protein and by a normal RB protein pattern on immunoblots. These findings support the concept that the RB gene acts as both a growth and tumor suppressor in bladder cancer cells.
The effect of mergocryptine, a new ergot alkaloid, on the cerebral dopaminergic systems was examined using Wistar rats. The administration of mergocryptine (1 and 10 mg/kg i.p.) induced a significant suppression of striatal dopamine (DA) turnover. In vitro addition of mergocryptine (0.01-100 microM) induced a dose-dependent suppression of the release of [3H]DA from striatal slices. Mergocryptine inhibited [3H]apomorphine binding to a striatal synaptosomal fraction, and its IC50 value was found to be 0.23 microM. Pretreatment with apomorphine (100 micrograms/kg s.c.) showed an additive effect on the mergocryptine (10 mg/kg)-induced suppression of DA turnover. These results suggest that mergocryptine may induce the suppression of striatal DA turnover by reducing DA release via the stimulation of presynaptic dopaminergic autoreceptors.
Immunoblot analyses of peroxisomal beta-oxidation enzymes showed that subunit A of acyl-CoA oxidase gave a stronger immunoreaction in fibroblasts of Zellweger and X-linked adrenoleukodystrophy patients than in those of controls. Subunits B and C and 3-ketoacyl-CoA thiolase were detected in fibroblasts of controls and X-linked adrenoleukodystrophy patients, but not of Zellweger patients. Total oxidation of palmitic and lignoceric acid was normal in homogenates of fibroblasts from Zellweger and X-linked adrenoleukodystrophy patients. The peroxisomal oxidation of both acids was only deficient in Zellweger patients. These data may not reflect the situation in vivo, as is evident from the accumulation of very-long-chain fatty acids in Zellweger and X-linked adrenoleukodystrophy patients.
We isolated and sequenced a gene, YS11A, encoding ribosomal protein YS11 of Saccharomyces cerevisiae. YS11A is one of two functional copies of the YS11 gene, located on chromosome XVI and transcribed in a lower amount than the other copy which is located on chromosome II. The disruption of YS11A has no effect on the growth of yeast. The 5'-flanking region contains a similar sequence to consensus UASrpg and the T-rich region. The open reading frame is interrupted with an intron located near the 5'-end. The predicted amino acid sequence reveals that yeast YS11 is a homologue to E. coli S4, one of the ram proteins, three chloroplast S4s and others out of the ribosomal protein sequences currently available.
Roots of several solanaceous plants produce anticholinergic alkaloids, hyoscyamine and scopolamine. Hyoscyamine 6 beta-hydroxylase, a 2-oxoglutarate-dependent dioxygenase (EC 1.14.11.11), catalyzes hydroxylation of hyoscyamine in the biosynthetic pathway leading to scopolamine. We report here on the isolation of cDNA clones encoding the hydroxylase from a cDNA library made from mRNA of the cultured roots of Hyoscyamus niger. The library was screened with three synthetic oligonucleotides that encode amino acid sequences of internal peptide fragments of the purified hydroxylase. Nucleotide sequence analysis of the cloned cDNA revealed an open reading frame that encodes 344 amino acids (Mr = 38,999). All 12 internal peptide fragments determined in the purified enzyme were found in the amino acid sequence deduced from the cDNA. With computer-aided comparison to other proteins we found that the hydroxylase is homologous to two synthases involved in the biosynthesis of beta-lactam antibiotics in some microorganisms and the gene products of tomato pTOM13 cDNA and maize A2 locus which had been proposed to catalyze oxidative reactions in the biosynthesis of ethylene and anthocyan, respectively. RNA blotting hybridization showed that mRNA of the hydroxylase is abundant in cultured roots and present in plant roots, but absent in leaves, stems, and cultured cells of H. niger.