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Biomedical subjects

S Izumo

Publications and source records attributed to S Izumo.

At least 217 records · Page 12Linked to original sources
PubMed1989

Germanium myopathy: clinical and experimental pathological studies.

Pathological examinations were carried out on the skeletal muscle of a patient with germanium intoxication. The prominent histochemical finding was vacuolar myopathy with lipid excess, increased acid phosphatase activity and decreased cytochrome c oxidase activity. Ultrastructural lesions revealed a mitochondrial abnormality, autophagic vacuoles and accumulation of high electron-dense materials in deformed mitochondria and at the periphery of lipid droplets. Furthermore, the toxic effect of germanium on skeletal muscle was confirmed by the experimentally induced germanium myopathy, which showed autophagic degeneration, decreased cytochrome c oxidase activity and a mitochondrial abnormality with high electron-dense materials.

Child, Preschool↗
PubMed1989

Nasu-Hakola disease (membranous lipodystrophy). Clinical, histopathological and biochemical studies of three cases.

We report 3 cases of Nasu-Hakola disease found in 2 families. These cases had identical clinical features with progressive spastic paraplegia and severe dementia after adolescence. They had no history of any skeletal symptoms, but roentgenographs of their bones presented characteristic evidence of polycystic osteodysplasia. All cases revealed not only manifestations of this condition in the central nervous system, but also peripheral neuropathy with axonal degeneration. The membranous structures in the adipose tissues appeared histochemically to be composed of a kind of compound glycolipid or glycoprotein. Histopathologically, the biopsied rectum showed the infiltration of many histiocytes in the mucosa and ultrastructurally, the granules in these histiocytes showed many membrane-bound vacuoles of different sizes. Interestingly, the histochemical reactivity of the material in the granules was very similar to that of membranous structures in adipose tissues. In the biochemical analysis of lipids in affected adipose tissues, no marked abnormalities were found in the patients. Nasu-Hakola disease is not a typical form of lysosomal storage disease, because lysosomal enzyme activities remain normal and there is no accumulation of urinary oligosaccharides and lipids, no vacuolation of lymphocytes, and no hepatosplenomegaly. However, histochemical findings suggest that the lysosomes may be secondarily involved in this disease, and that the formation of membranous structures might be related to the disturbance of glycolipid or glycoprotein metabolisms.

Adipose Tissue↗
PubMed1989

Type IIa hyperlipoproteinemia masquerading as cerebrotendinous xanthomatosis.

We describe an adult patient with type IIa hyperlipoproteinemia, presenting with Achilles tendon xanthomas, cataracts, dementia, ataxia, pyramidal tract signs, and peripheral neuropathy, which are commonly seen in cerebrotendinous xanthomatosis (CTX). However, the diagnosis of CTX was excluded on the basis of the cholestanol level and the normal cholestanol/cholesterol ratio in his serum and tendon. The pathomechanism for some of the clinical manifestations in type IIa hyperlipoproteinemia and CTX might be caused by a common biochemical disturbance.

Aged↗
PubMed1989

In vitro modulation of lymphocyte proliferation by prednisolone and interferon-alpha in patients with HTLV-I-associated myelopathy (HAM).

One of the hallmarks of human T-lymphotropic virus type I (HTLV-I) infection is the proliferation in vitro of peripheral blood lymphocytes (PBLs) in the absence of growth factors. This phenomenon, the autologous proliferative response (APR), involves spontaneous growth of HTLV-I-infected T-cells and proliferation of T-cells in response to the infected cells. We studied the modulating effect of prednisolone (PSL) and interferon-alpha (IFN) on APR of PBLs obtained from five patients with HTLV-I-associated myelopathy (HAM). APR was significantly inhibited by PSL and IFN suggesting that APR is important in the pathogenesis of HAM.

Adult↗
PubMed1989

Activated T lymphocytes in cerebrospinal fluid of patients with HTLV-I-associated myelopathy (HAM/TSP).

In order to detect activated T lymphocytes in the cerebrospinal fluid (CSF) of patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we studied CSF lymphocytes in untreated patients with HAM/TSP and other neurological diseases (OND). Dual-immunofluorescence staining technique was performed using fluorescence microscopy. No significant difference in the CD4+/CD8+ ratio of CSF lymphocytes was observed between HAM/TSP patients and patients with OND. However, both CD4+ and CD8+ CSF lymphocytes of HAM/TSP patients contained higher percentages of HLA-DR-positive cells than those of patients with OND (P less than 0.05), suggesting that the activated CSF T lymphocytes were composed of both CD4+ and CD8+ subsets in patients with HAM/TSP.

Antibodies, Monoclonal↗
PubMed1989

The expression of sarcomeric muscle-specific contractile protein genes in BC3H1 cells: BC3H1 cells resemble skeletal myoblasts that are defective for commitment to terminal differentiation.

The BC3H1 cell line has been used widely as a model for studying regulation of muscle-related proteins, such as the acetylcholine receptor, myokinase, creatine kinase, and actin. These cells, derived from a nitrosourea-induced mouse brain neoplasm, have some of the morphological characteristics of smooth muscle and have been shown to express the vascular smooth muscle isoform of alpha-actin. To provide further information about the contractile protein phenotype of BC3H1 and to gain additional insights into the possible tissue of origin of these cells, we have examined the expression of a battery of contractile protein genes. During rapid growth, subconfluent BC3H1 cells express the nonmuscle isoform of alpha-tropomyosin (alpha-Tm) and the nonsarcomeric isoforms of myosin heavy and light chains (MHCs and MLCs, respectively), but do not express troponin T(TnT). However, when BC3H1 cells differentiate in response to incubation in serum-deprived medium or upon approaching confluence, they express TnT as well as sarcomeric muscle isoforms of MHC, MLC 2 and 3, alpha-Tm, and alpha-actin. These results suggest that BC3H1 is a skeletal muscle cell line of ectodermal origin that is defective for commitment to terminal differentiation.

Actins↗
PubMed1989

Determination of urine thiocyanate in patients with amyotrophic lateral sclerosis.

It has been reported that amyotrophic lateral sclerosis-Parkinsonism-dementia in Guam might be related to the eating of Cycas seeds, which contain cyanide. Based on this assumption, we determined the urinary thiocyanate excretion level in patients with ALS and compared this with that of other neurological diseases. The assay method was designed to use column chromatography with Amberlite IRA 402. The thiocyanate level was determined using pyridine-barbiturate method. The 24-h thiocyanate level was higher in the ALS patients of the middle stages than in the normal control group (Wilcoxon's test, P less than 0.02). There were no significant differences between the ALS patient groups of the early and terminal stages, Kugelberg-Welander disease group, Duchenne type muscular dystrophy group and control group. From these results, we concluded that ALS patients were contaminated with cyanide or thiocyanate and that, along with rapid muscular atrophy, the thiocyanate excretion levels were high.

Adult↗
PubMed1989

[Two cases of facial diplegia with elevated serum antibodies to Borrelia burgdorferi].

Lyme disease, a tick-borne infection with spirochete named Borrelia burgdorferi, is a complex multi-organ disorder involving neurological complication. Recently, the existence of Lyme disease was also recognized in middle Japan. We described here two cases of facial diplegia with elevated serum antibodies to B. burgdorferi. Case 1 was a 48 year-old man, who developed facial diplegia on April 29, 1987, and referred to our hospital on May 1. Neurological examination showed facial diplegia in addition to right-sided hemiparesis due to head injury of twenty years ago. The cell count of the cerebrospinal fluid was 17/mm3 and the protein was 139.9 mg/dl. The serological examinations for B. burgdorferi were performed by means of immunoperoxidase test. This patient had no serum IgG antibodies to B. burgdorferi on admission. However, twelve weeks later his serum showed significant elevation of IgG antibodies (titer: X400). Tests for syphilis and leptospira were negative. Based on these observation, we considered that facial diplegia of this patient was associated with the infection of B. burgdorferi. His facial diplegia remained unchanged with oral corticosteroid treatment. Case 2 was a 64 year-old man, who developed facial diplegia on May 31, 1987, and referred to our hospital on June 3. Neurological examinations were entirely negative except for facial diplegia. The findings of the cerebrospinal fluid showed the albumin cytologic dissociation with the cell count 2/mm3 and the protein 85.4 mg/dl. Serum IgG antibodies to B. burgdorferi were present (titer: X200) on admission. However, seven weeks later his serum showed a marked elevation of IgG antibodies (titer: X1600). Tests for syphilis were negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗
PubMed1988

Thyroid hormone receptor alpha isoforms generated by alternative splicing differentially activate myosin HC gene transcription.

Thyroid hormones are thought to modulate gene expression positively or negatively through interactions with chromatin-associated receptors. Recently, the c-erb A proto-oncogene products have been shown to be nuclear thyroid hormone (T3) receptors (TR) by sequence similarity with other steroid receptors and by their ability to bind thyroid hormone. But it has not been shown that these receptors directly activate transcription of the responsive genes in vivo. In addition, the rat TR alpha gene encodes several messenger RNA (mRNA) species, generated by differential processing of its transcripts (ref. 22). For these reasons we investigated the ability of two major isoforms of the rat TR alpha gene products to activate transcription of a sarcomeric myosin heavy chain (mHC) gene, because expression of all members of this gene family is responsive to T3. We show here that the rTR alpha 1 receptor is a thyroid hormone-dependent transcriptional factor, which upon binding the T3 responsive element of the alpha-mHC gene, activates expression of this gene in vivo. The rTR alpha 2 isoform, which is identical to rTR alpha 1 except for its carboxyl terminal portion, is generated by alternative splicing of the rTR alpha gene transcript. This peptide, when produced in vitro and in vivo failed to bind T3 or other hormones or to trans-activate alpha-mHC gene expression. Thus, alternative splicing can produce marked differences in the functional properties of a transcriptional factor.

Acetyltransferases↗
PubMed1988

Muscle is the major source of plasma gelsolin.

Gelsolin, a Ca2+- and polyphosphoinositide-regulated actin-binding protein, is unique among vertebrate proteins in being both cytoplasmic and secreted. Plasma gelsolin, present at greater than 200 micrograms/ml in human plasma, may have a protective function by promoting the clearance of actin filaments released during tissue injury. Although there is evidence that smooth muscle tissues and HepG2 cells synthesize plasma gelsolin, the predominant secretory source is hitherto unknown. We report here that skeletal, cardiac, and smooth muscles have large amounts of plasma gelsolin mRNA and devote 0.5-3% of their biosynthetic activity to plasma gelsolin, whereas liver makes relatively little. Since skeletal muscle accounts for a large fraction of body mass and total protein synthesis, it is the major source of plasma gelsolin.

Animals↗
PubMed1988

Spinal roots of rats poisoned with methylmercury: physiology and pathology.

The evoked potentials in the ventral and dorsal roots were recorded independently by stimulating the sciatic nerve of both control and methylmercury-poisoned rats. Poisoned rats showed markedly decreased amplitudes but normal latencies of the potentials evoked in the dorsal roots. Potentials evoked in the ventral roots had normal latencies and amplitudes. Pathological correlates indicated acute axonal degeneration of the dorsal roots, with a significant decrease of the large and small myelinated fiber densities. The ventral roots were histologically unremarkable. Our pathological confirmation of the electrophysiologic changes in the methylmercury-poisoned rats enables us to substantially assess the pathophysiological aspects of acute lesions in the spinal roots.

Animals↗
PubMed1988

Protooncogene induction and reprogramming of cardiac gene expression produced by pressure overload.

Hypertrophy, an increase in cell size without cell division, is a fundamental adaptive process employed by postmitotic cardiac and skeletal muscle cells. Cardiac myosins undergo an adult-to-fetal isoform transition in various models of hypertrophy. Using gene-specific cDNA probes, we show here that in the adult myocardium the mRNAs encoding the fetal (skeletal muscle type) isoforms of alpha-actin and sarcomeric tropomyosin are re-expressed within 2 days in response to pressure overload. In addition, atrial natriuretic factor mRNA, so far believed to be expressed primarily in the atria, was readily detectable in the ventricles of neonates and was induced to markedly high levels in pressure-overloaded adult ventricles. In contrast, cardiac hypertrophy produced by thyroid hormone excess was not associated with induction of the atrial natriuretic factor gene or fetal contractile protein isogenes. Furthermore, the c-fos and c-myc protooncogenes and a major heat shock protein gene (hsp70) are induced in the ventricular myocardium within 1 hr after imposition of pressure overload. These results suggest that induction of cellular protooncogenes and heat shock (stress) protein genes is an early response to pressure overload, whereas reinduction of the genes normally expressed only in perinatal life, such as fetal isoforms of contractile proteins and atrial natriuretic factor, is a later event. These two types of responses might represent the general pattern of growth induction to work overload by terminally differentiated cells that have lost the ability to undergo DNA replication.

Aging↗
PubMed1988

Sural nerve morphology in asymptomatic uremia.

This study evaluates morphologically the sural nerves of two patients with acute and another pair with chronic uremia, both of whom had neither clinical nor electrophysiologic evidence of neuropathy. Morphometric changes indicative of myelin repair were noted in the chronic uremic case who had a shorter duration of renal failure but required dialysis. Also, changes suggestive of axonal degeneration were found in the case who had chronic uremia of long duration. Both cases of acute uremia did not reveal significant abnormalities. Structural changes in the sural nerves may precede clinical and nerve conduction derangements in uremia, specifically in chronic cases.

Acute Disease↗
PubMed1988

Immunological studies of HTLV-I associated myelopathy.

We report the immunological studies of 50 cases with a chronic progressive myelopathy associated with elevated antibodies to human T-cell lymphotropic virus type I (HTLV-I) and adult T-cell leukemia-like cells (HAM). These are as follows: (1) T-cell activation; (2) increase of the OKT4/OKT8 ratio, due mostly to increased inducer/helper T cells and/or decreased suppressor/cytotoxic T cells; (3) decrease of natural killer cell numbers and activity; and (4) increase of immunoglobulins (IgG, IgA). Our results provide evidence that autoimmune events may participate in the pathogenesis of HAM and may be relevant in the hypothesis of common immune mechanisms between HAM and HTLV-I positive tropical spastic paraparesis.

Adult↗