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Biomedical subjects

Y Eto

Publications and source records attributed to Y Eto.

At least 199 records · Page 11Linked to original sources
PubMed1990

Galactosylceramide and galactosylsphingosine loading studies in cultured skin fibroblasts in human and murine globoid cell leukodystrophy.

Cell level studies of 3H-galactosylceramide(GalCer) and 3H-galactosyl sphingosine (GalSph) have been carried out in cultured skin fibroblasts from human and murine globoid cell leukodystrophy (GLD). GalCer loading studies disclosed that the hydrolysis rates of GalCer in human control and GLD were 72% and 45%, respectively, and those from the murine control and GLD cells were 77% and 21%, respectively, on the 5th day of culture. On the other hand, GalSph loading studies showed that the hydrolysis rate of GalSph in the human control and GLD were 40% and 10%, respectively, and those from murine control and GLD cells were 38% and 10% on the 12th day of culture. These data suggest that both GalCer and GalSph degradations were impaired in cell level in human and murine GLD. Furthermore, when radioactive 3H-GalSph was loaded into cultured fibroblasts from murine and human GLD, 3H-GalCer band was formed via GalSph. These data strongly suggest that GalCer could be synthesized through the GalSph route as a minor pathway at least in cultured skin fibroblasts, although the major pathway to synthesize GalCer should be via ceramide.

Animals↗
PubMed1990

Abnormality in cultured oligodendrocytes and Schwann cells isolated from the twitcher mouse.

Oligodendrocytes and Schwann cells were isolated from the brain and dorsal root ganglia of the twitcher mouse, a murine model of Krabbe's disease (globoid cell leukodystrophy), and grown in tissue culture. Oligodendrocytes were cultured for up to 22 d in vitro and were immunostained with a galactocerebroside antibody, a specific marker for oligodendrocytes. The control oligodendrocytes developed well-branched processes and membrane sheets, whereas the twitcher oligodendrocyte had wirelike processes with no membrane expansion and progressive degeneration. Schwann cells from the twitcher could not extend their processes as long as normal counterparts. The amounts of psychosine in the enriched population of oligodendrocytes and Schwann cells from the twitcher mouse are about 50-fold and 70-fold higher, respectively, than those in the control cells. These data suggest that psychosine may play an important role in the progression of abnormal features of oligodendroglial membrane formation and in the absence of process elongation in Schwann cells in the twitcher mutant.

Animals↗
PubMed1990

Biochemical and morphological studies of dorsal root ganglion and its cultured cells from twitcher mouse (murine globoid cell leukodystrophy).

The biochemical pathogenesis of globoid cell leukodystrophy (GLD) (Krabbe disease) was investigated in vitro using the cultured neural cells obtained from dorsal root ganglion (DRG) of twitcher mouse (murine Krabbe disease). Electron microscopic examination of twitcher DRG of 30 days old showed the demyelination and abnormal inclusion bodies, whereas mitochondrial structure appeared to be intact. Cultured neural cells from control mice were well proliferated to form the network processes, while those from twitcher were decreased in cell numbers and showed the vacuolation of cell body, degeneration of processes, and finally died after three weeks. There was no apparent difference of lipid composition between control and twitcher DRG, and the galactocerebroside levels from control were similar to those of twitcher. However, marked accumulation of psychosine was found in the 30-day-old-twitcher DRG. The level of psychosine from twitcher DRG was elevated approximately 70 to 80-fold compared with those of control. These data suggest that neural cells from twitcher mice degenerative with age also in vitro and accumulation of psychosine in twitcher DRG may play an important role for the demyelination in GLD.

Animals↗
PubMed1990

Abnormal urinary excretion of polyamines in HHH syndrome (hyperornithinemia associated with hyperammonemia and homocitrullinuria).

The HHH syndrome (hyperornithinemia associated with hyperammonemia and homocitrullinuria) is characterized by a very rare genetic defect of ornithine transport in mitochondrial membrane. We first demonstrated that a patient with HHH syndrome excreted about 6 times higher amount of polyamines in urine than the control when supplemented with high protein diets and ornithine loading. Each urinary polyamine fraction measured by HPLC method in HHH syndrome appears to be increased, as compared with those of the control. These data suggest that increased urinary excretion of polyamines in this syndrome is closely related to overflowing of plasma polyamine due to an ornithine transport defect in the mitochondrial membrane.

Adolescent↗
PubMed1990

Biochemical pathogenesis of demyelination in globoid cell leukodystrophy (Krabbe's disease): the effects of psychosine upon oligodendroglial cell culture.

The effects of psychosine on the metabolism of myelin associated glycolipids such as galactocerebroside and sulfatide in mouse brain cell cultures were investigated in order to clarify the mechanism of demyelination in globoid cell leukodystrophy (Krabbe's disease). The incorporation of 3H-galactose into cerebroside and sulfatide was studied in the presence of psychosine (1-3 micrograms/ml medium). These data indicated that psychosine inhibited the incorporation of 3H-galactose into cerebroside and sulfatide not in astroglial cell culture but in oligodendroglial cell culture. Oligodendrocytes produce myelin in the central nervous system, and cerebroside and sulfatide are major components of myelin. These results suggest that psychosine influences the lipid metabolisms of myelin and subsequently leads to the demyelination in Krabbe's disease.

Animals↗
PubMed1990

Lysosulfatide (sulfogalactosylsphingosine) accumulation in tissues from patients with metachromatic leukodystrophy.

We describe here a sensitive assay method for lysosulfatide (sulfogalactosylsphingosine) in human tissues using HPLC. The method involves extraction of lipids, saponification, isolation using a C18 Sep-Pak column, derivatization with o-phthalaldehyde, and detection of the fluorescent lysosulfatide using HPLC. In control subjects, a small amount of lysosulfatide was detected in the cerebral white matter (9-35 pmol/mg of protein), spinal cord (35 pmol/mg of protein), sciatic nerve (14 pmol/mg of protein), and kidney (approximately 2 pmol/mg of protein) but not in the cerebral gray matter and liver. A marked accumulation of the lipid was noted in tissues from six patients with metachromatic leukodystrophy (MLD). The concentration of lysosulfatide was high in the cerebral white matter, spinal cord, and sciatic nerve (223-1,172 pmol/mg of protein). Even in the cerebral gray matter, kidney, and liver, where lysosulfatide was hardly detected in the control sample, a considerable amount (3-45 pmol/mg of protein) accumulated in MLD patients. The concentration and distribution pattern of lysosulfatide were similar to those of galactosylsphingosine (psychosine) accumulated in patients with Krabbe disease. Therefore, the accumulation of lysosulfatide may explain the demyelination in patients with MLD, as is the case with Krabbe disease.

Cerebroside-Sulfatase↗
PubMed1990

Cytoplasmic accumulations in rat primary brain cell cultures following treatment with E-64, a thiol protease inhibitor.

The present communication deals with morphological effects of E-64, a thiol protease inhibitor, on primary cultures dissociated from 15-day-old fetal rat brain. Brain cells were treated with different concentrations of E-64 varying from 0.1 to 50 micrograms/ml medium. Numerous cytoplasmic accumulations appeared in neuronal cells, astrocytes and oligodendrocytes exposed to a concentration of 1.0 micrograms/ml of E-64 or higher, and after withdrawal of E-64, the accumulations disappeared. These accumulations were immunocytochemically stained with the antibody against cathepsin B, a marker of lysosomal activity, and the staining patterns found with acid phosphatase were similar to those found with cathepsin B. It is hypothesized that the cytoplasmic accumulations were lysosomes and that the action of E-64 was reversible. Use of thiol protease inhibitors on primary brain cell culture may be an appropriate model system for studying protein storage diseases in neuronal cells.

Animals↗
PubMed1990

Psychosine cytotoxicity in rat neural cell cultures and protection by phorbol ester and dimethyl sulfoxide.

In Krabbe's disease (globoid cell leukodystrophy), galactosylsphingosine (psychosine) is considered to be a causative agent of the pathology found in the nervous system of the patients. In our study, we examined the cytotoxic effect of psychosine in neural cell cultures derived from the rat nervous system. The concentration of toxic thresholds varied from cell type to cell type. The 50% of toxic doses for oligodendrocytes, astrocytes, and the sensory neurons of the dorsal root ganglia were 8, 20, and 30 micrograms/mL, respectively. Oligodendrocytes, therefore, appeared to show a higher sensitivity to psychosine than did astrocytes or neurons. When phorbol ester or DMSO was applied simultaneously with psychosine as protective agents in enriched cultures of rat oligodendrocytes, the total number of live cells and galactocerebroside-positive cells and the 2'3'-cyclic nucleotide 3'-phosphohydrolase activity in these cultures were considerably higher as compared with their levels in the experimental cultures treated with psychosine alone. These results indicate that phorbol ester and DMSO could serve as protective agents for psychosine neurotoxicity.

Animals↗
PubMed1990

[Molecular basis of organic acidemia--propionic acidemia].

Propionic acidemia is an inborn error of organic acid metabolism caused by deficiency of propionyl-CoA carboxylase (PCC: E. C. 6. 4. 1. 3.). We have detected three types of mutation in the same exon of the coding sequence of beta-subunit of PCC (beta PCC) from two ethnic background (Caucasians and Japanese): an insertion/deletion which replaces 14 nucleotides with 12 unrelated nucleotides results in the elimination of an Msp I site; a 3-bp inframe deletion results in loss of one of two consecutive isoleucine codons immediately preceding the same Msp I site; the C----T transition results a in loss of the same Msp I site. The insertion/deletion and the C----T transition show high allele frequency in Caucasians (0.32) and in Japanese (0.3), respectively. These results reveal the possibility of the independent origin of the mutation in the two ethnic backgrounds and suggest a key role of this exon in the structure and catalytic function of the beta-subunit of PCC.

Acyl Coenzyme A↗
PubMed1989

In vivo treatment with erythroid differentiation factor (EDF/activin A) increases erythroid precursors (CFU-E and BFU-E) in mice.

The in vivo effect of human EDF on erythroid precursors (CFU-E and BFU-E) was investigated in normal and bled mice. In anemic (bled) mice, EDF treatment led to significant dose-dependent rises in the CFU-E and BFU-E levels of bone marrow. An elevation in the level of CFU-E was also seen in the spleen. In normal mice, a significant elevation in the level of bone marrow BFU-E was observed. Thus, EDF has an effect on erythropoiesis in anemic and normal mice in vivo.

Activins↗
PubMed1989

Characterization of cellular receptors for erythroid differentiation factor on murine erythroleukemia cells.

Erythroid differentiation factor (EDF), which is structurally related to transforming growth factor-beta family and induces differentiation of murine erythroleukemia cell clone F5-5, has been labeled with 125I to characterize its interaction with cellular receptors. Binding of 125I-EDF to F5-5 cells is time- and temperature-dependent, specific, saturable, and reversible. Transforming growth factor-beta 1 has no significant effects on growth of F5-5 cells and binding of 125I-EDF to F5-5 cells. Scatchard analysis of the binding data indicated that F5-5 cells have a single class of binding sites (3,200/cell) with an apparent Kd of 3.1 X 10(-10) M. Affinity cross-linking experiments demonstrated three radiolabeled components of 140,000, 76,000, and 67,000 daltons under both reducing and nonreducing conditions. Labeling of these three components has been inhibited by incubation of the cells with excess unlabeled EDF. These results imply molecular weights of 115,000, 51,000, and 42,000 for the EDF receptors on this cell line.

Activins↗
PubMed1989

Stimulation of insulin secretion by transforming growth factor-beta.

Effects of transforming growth factor-beta (TGF-beta) on insulin secretion were studied in rat pancreatic islets. When islets were incubated in a batch incubation system with various concentrations of TGF-beta in the presence of 2.8 mM glucose, TGF- beta increased insulin release in a concentration-dependent manner. Both TGF- beta 1 and TGF- beta 2 were equally effective. The stimulatory action of TGF- beta was greater in the presence of stimulatory concentration of glucose. In perifusion system, TGF- beta induced an immediate monotonic increase in insulin secretion. These results indicate that TGF- beta is a stimulator of insulin secretion.

Animals↗
PubMed1989

Fetal GM1-gangliosidosis: morphological and biochemical studies.

A 23-week fetus with GM1-gangliosidosis type 1 was studied morphologically and biochemically. The GM1-ganglioside content in the brain was approximately twice that of a control. A GM1-ganglioside comprised about 25% of the total ganglioside NANA (N-acetyl-neuraminic acid), whereas in control fetus brain the proportion was 14.3%. The storage of GM1-ganglioside in fetal GM1-ganglioside brain was confirmed by a thin-layer chromatogram immunostained with anti-GM1-ganglioside antibody. The accumulation of GM1-ganglioside in visceral organs (liver, spleen and kidney) was not detected with biochemical and immunochemical methods. However, in hepatocytes, Kupffer cells, renal tubular cells and spleen cells from the affected fetus, there were many vacuoles which could contain oligosaccharides as storage materials. These data suggest that pathochemical changes in the brain and visceral organs of an affected fetus are already evident in the second trimester of the pregnancy. Tissue specific accumulation of glycolipids or oligosaccharides in fetal GM1-gangliosidosis suggests that the biosynthesis or degradation of these compounds occurs at different periods.

Adult↗
PubMed1989

[Application of neuronal cell culture in human degenerative brain disorders].

Neuronal cell culture system has been used for the study of pathochemical evaluations in human degenerative brain disorders, particularly for Krabbe's disease and neuronal ceroid lipofuscinosis. To understand the pathochemistry of Krabbe's disease, we added psychosine into neuronal cell cultures and psychosine treated cells showed the destruction of cytoskeleton and pathy intracellular changes. Electron microscopic finding showed the swelling of the mitochondria. Oligodendrocytes and Schwann cells were isolated from the brains and sciatic nerve of twitcher mouse as an authentic murine model of globoid cell leukodystrophy. Oligodendroglial cells cultured for 22 days were stained by anti-galactocerebroside antibodies. In twitcher oligodendrocyte processes were wirelike and progressively degenerated and there were few membranous expansion. Schwann cells from twitcher could not elongated their processes. These data suggest that psychosine might be important factor to result in these pathological conditions. Furthermore, we studied the effect of protease inhibitors, E-64 on dissociated primary cultures from fetal rat brain. After treated with E-64 in a concentration from 0.1-50 micrograms/ml, numerous cytoplasmic accumulations appeared in neuronal cells. These morphological pictures resemble with those of neuronal ceroid lipofuscinosis, Batten disease. We will discuss the relationship between the deficiency of catepsin H in Batten disease and inclusion bodies found in E-64.

Age Factors↗