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Biomedical subjects

Y Eto

Publications and source records attributed to Y Eto.

At least 163 records · Page 9Linked to original sources
PubMed1993

Indirect strong inhibition by acid-stable trypsin-plasmin inhibitor (ASTPI) of the activations of elastase and plasma fibrinolysis in a dog model of acute pancreatitis.

Acid-stable trypsin-plasmin inhibitor (ASTPI) had almost no direct effect on the increased levels of the plasma enzymes elastase, plasmin and plasminogen activators in an acute pancreatitis model in the dog, whereas it strongly inhibited the activation of such enzymes by intravenous administration. In vivo experiments also showed strong inhibition by ASTPI of pancreas tissue elastase and plasma fibrinolysis. Anti-shock and anti-pancreatitis effects of ASTPI observed in clinical therapy may be related to this "indirect inhibition".

Acute Disease↗
PubMed1993

[Molecular analysis of Japanese patients with metachromatic leukodystrophy].

Metachromatic leukodystrophy (MLD) is a lysosomal storage disorder caused by a deficiency of arylsulfatase A (ASA). Three forms of the disease can be distinguished according to the age at onset: late-infantile, juvenile and adult. To investigate the molecular basis of Japanese patients with MLD, we examined ten Japanese patients for the presence of three known ASA mutations. The results indicate quite different distribution of these mutations between Caucasian and Japanese patients with MLD. We have performed further analysis on ASA gene of Japanese MLD patients, and identified two new mutations. Phenotype-genotype relationship in Japanese patients with MLD is discussed.

Age of Onset↗
PubMed1993

[SPECT (single photon emission computed tomography) findings in 4 cases of neuronal migration disorders].

We report SPECT findings in four children with various types of neuronal migration disorders. SPECT of a patient with heterotopia showed a protrudent abnormal shadow into the centrum semiovale, the density of which was same as that of normal gray matter. The function and the metabolism of heterotopia appear same as those of the normal gray matter. SPECT of a patient with pachygyria showed decreased blood flow in the areas of thickened cortex. This finding seems to indicate hypofunction of those lesions. SPECT of a patient with hemimegalencephaly showed an increased blood flow in the ipsilateral hemisphere and decreased blood flow in the contra-lateral hemisphere. In the literature, increased contents of neuronal elements in the affected site and arterio-venous shunt with cardiac failure have been reported in hemimegalencephaly. These pathologies may be related to our SPECT findings. SPECT of a patient with cortical dysplasia showed extensive lesions of decreased blood flow which was more wide spread than abnormal lesions detected by MRI. SPECT may be more sensitive than MRI to detect cortical dysplasias.

Adolescent↗
PubMed1992

Cloning and sequencing of a rat type II activin receptor.

A full-length cDNA for a rat type II activin receptor was cloned by hybridization from a rat ovary cDNA library. The deduced amino acid sequence (513 residues) containing a single membrane-spanning domain and an intracellular kinase domain with predicted serine/threonine specificity. The amino acid sequence is 99.8% and 99.4% identical in the coding region with the previously cloned mouse and human type II activin receptor, and only 66.7% identical in the coding region with the previously cloned rat type IIB activin receptor. We examined the effect of PMSG-hCG on the mRNA level of type II activin receptor in immature rat ovaries. Northern blot analysis of ovarian RNA revealed two mRNAs (3.0 kb and 6.0 kb).

Activin Receptors↗
PubMed1992

The measurement of activin/EDF in mouse serum: evidence for extragonadal production.

Many studies have shown that activin/EDF mediates local physiological events at various sites. In this study, the authors confirmed the presence of activin in mouse serum by high performance liquid chromatography (HPLC) monitored by a specific bioassay. The retention time of the active fraction in HPLC was identical to that of authentic activin A, and the activity was neutralized by follistatin. That the serum activin levels in ovariectomized and aged mice were decreased suggests that the serum activin was generated partly by ovary (35%), but also by extragonadal organs. Activin and inhibin are structurally closely related, and both are involved in many physiological processes including control of follicle stimulating hormone secretion by the pituitary. The regulation of serum activin, however, appeared to differ from that of inhibin.

Activins↗
PubMed1992

Isolation and characterization of activin receptor from mouse embryonal carcinoma cells. Identification of its serine/threonine/tyrosine protein kinase activity.

The activin receptor protein was isolated from the mouse embryonal carcinoma (EC) cell line P19 by three cycles of affinity chromatography on an activin A-immobilized column. The purified receptor had a specific and high affinity for activins A, AB, and B (Kd = 345 pM), but not for transforming growth factor beta. The purified activin receptor was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and ligand blotting analysis as a single protein of 70 kDa. The amino acid sequence of the first 18 NH2-terminal residues revealed that the receptor is a member of the activin receptor family. The purified receptor phosphorylated itself and exogenous substrate proteins on serine, threonine, and tyrosine residues, indicating that the activin receptor is a transmembrane serine/threonine/tyrosine protein kinase. These results suggest that signal transduction of activin employs a novel pathway via a new class of cellular receptor in EC P19 cells.

Activin Receptors↗
PubMed1992

Induction of differentiation of the human promyelocytic cell line HL-60 by activin/EDF.

A human promyelocytic cell line, HL-60, treated with activin/EDF was found to differentiate into monocyte/macrophage-like cells. This was shown not only by morphology but by the loss of myeloperoxidase granules and the appearance of nonspecific esterase. Dose-dependent inhibition of the differentiation by follistatin, an activin-binding protein, confirmed that it was indeed caused by activin. Thus, activin/EDF exerts its effect on hematopoietic cells not only on erythroid differentiation but also on at least a part of myeloid cell differentiation.

Activins↗
PubMed1992

Isolation and characterization of native activin B.

To examine whether activin binds to follistatin, an activin-binding protein, to form a complex in vivo, we attempted to purify activin-follistatin complex from porcine follicular fluid. Our results thus obtained indicated that almost equimolar amounts of activins A, AB, and B are present as a complex with follistatin in the follicular fluid. Reverse-phase high performance liquid chromatography of the purified complex yielded follistatin and activins A, AB, and B. The activity of the purified activin B was found to be significantly lower than those of other activins in various assay systems such as stimulation of follicle-stimulating hormone secretion, induction of erythrodifferentiation, and potentiation of expression of gonadotropin receptors on ovarian cells. Moreover, binding of 125I-activin A to erythroleukemic cells which are activin-responsive was competed by activin B with approximately 10-fold lower potency compared with other activins. In contrast to these results, activin B was proved to have a potent Xenopus mesoderm-inducing activity, comparable with that of other activins. This indicates that, unlike activins A and AB, activin B can only elicit mesoderm-inducing activity and cannot function in other biological systems, suggesting a specific role of activin B in early development and unknown biological functions.

Activins↗
PubMed1992

Competitive protein binding assay for activin A/EDF using follistatin determination of activin levels in human plasma.

A sensitive and specific protein binding assay for activin A/EDF (activin) was developed using follistatin as a binding protein and [125I] labelled activin as a tracer. As 50% acetonitrile (CH3CN) separated free and follistatin-bound activin, plasma pretreated with an equal volume of CH3CN was used as the assay sample and B/F separation was also done with 50% CH3CN. The recovery of the assay was 85.0% and its sensitivity was 0.5 ng/ml. Crossreactivity with inhibin A was 1.8%. The mean plasma level of follistatin-free activin in normal subjects was 1.3 +/- 0.7%. (M +/- SD) ng/ml. Plasma free activin levels were generally elevated in patients with chronic renal failure or hematological diseases associated with anemia.

Activins↗
PubMed1992

Succinate-dependent lipid peroxidation and its prevention by reduced ubiquinone in beef heart submitochondrial particles.

When succinate and ADP-Fe3+ chelate were added to beef heart submitochondrial particles pretreated with 2-thenoyltrifluoroacetone, an inhibitor of succinate dehydrogenase of the mitochondrial respiratory chain, the formation of malondialdehyde was observed. No formation was observed without the pretreatment. Oxaloacetate competitively inhibited the malondialdehyde formation with an apparent Ki of 3.4 microM. The malondialdehyde formation seemed to be initiated at the location between the p-hydroxymercuribenzoate-sensitive site and the 2-thenoyltrifluoroacetone-sensitive site of the succinate dehydrogenase because it was inhibited by the mercurial. Ubiquinone-10 was rapidly destroyed during the malondialdehyde-forming reaction when it was in the oxidized form, while the ubiquinone was not destroyed and the malondialdehyde formation was abolished when about 50% of the ubiquinone in the particles was in the reduced state. These observations suggest that the succinate-dependent peroxidation is strongly controlled by the redox state of ubiquinone.

Animals↗
PubMed1992

Follistatin is a developmentally regulated cytokine in neural differentiation.

Activin acts mitogenically on P19 cells as well as being inhibitory of the differentiation of retinoic acid-treated P19 cells and some neuroblastoma cell lines. Here, we show some lines of evidence that follistatin, an activin-binding protein, is also involved in neural differentiation. Counteracting the activity of activin, addition of follistatin suppresses the anchorage-independent growth of P19 cells in soft agar and stimulates neurite outgrowth of a neuroblastoma cell line, IMR-32 cells. While activin does not seem to be expressed significantly, follistatin is demonstrated in the conditioned medium of these cells. Furthermore, the expression of follistatin in P19 cells is subject to dynamic fluctuations in response to retinoic acid treatment. These neural cells may produce follistatin in a cell stage-specific manner in order to interact with exogenously derived activin.

Activin Receptors↗
PubMed1992

Evidence for the participation of endogenous activin A/erythroid differentiation factor in the regulation of erythropoiesis.

Activin A/erythroid differentiation factor (EDF) is a human protein that induces differentiation of a murine erythroleukemia cell (the Friend cell). In this study, we demonstrate that endogenous activin A/EDF activity is present in murine bone marrow and spleen. In addition, this activity is secreted by bone marrow and spleen cells in primary culture. Administration of follistatin (a specific binding protein for activin A/EDF) to mice results in a decrease of erythroid progenitors in the bone marrow and spleen. These findings support the concept that activin A/EDF and follistatin have opposing actions in the regulation of erythropoiesis.

Activins↗
PubMed1992

The existence of activin A/erythroid differentiation factor and its inhibitor in human serum: comparison of normal and chronic renal failure sera.

Activin A/EDF, initially found as a differentiation inducer of murine Friend erythroleukemia, also has a stimulatory effect on erythropoiesis in vitro and in vivo. Here we proved activin A/EDF activity in human serum. The activin A/EDF level in 18 normal human serum samples was measured by a specific bioassay and was found to be 8.3 +/- 4.6 ng/ml, indicating that there exists sufficient activity to affect erythropoiesis in normal serum. In contrast, activin A/EDF activity was reduced in the chronic renal failure patients and 23/26 serum samples examined showed levels below 1.2 ng/ml. Further analysis using HPLC revealed that chronic renal failure serum actually contained as much activin A/EDF as normal serum, and that the difference between normal and patient serum existed in the content of a specific inhibitor of activin A/EDF. This observation suggests the possibility that the inhibitor is participating in the regulation of activin A/EDF activity in vivo in chronic renal failure patients and also the possibility of activin A/EDF could be utilized in the therapy of the anemia of such patients.

Activins↗
PubMed1992

Rapid identification of mutations in the glucocerebrosidase gene of Gaucher disease patients by analysis of single-strand conformation polymorphisms.

To detect mutations in the glucocerebrosidase gene in Gaucher disease patients, we used the recently described technique of single-strand conformation polymorphism (SSCP) analysis in combination with selective amplification. We analyzed exon 8, 9, 10 and 11 of the glucocerebrosidase gene; these exons were sequentially amplified using the selectively amplified products as templates. We found variant SSCP patterns corresponding to the presence or absence of the 6433C mutation, which was detected by NciI digestion analysis, in exon 10. Furthermore, we detected four variant SSCP patterns in exon 8, 10 and 11. Sequencing analysis consistently revealed four single-base substitutions in the corresponding exons, three novel missense mutations (5409A, 6375G and 6682T) and one silent polymorphism (6594A). These mutations were found only in one patient; therefore, these findings have confirmed the marked genetic heterogeneity of Gaucher disease. SSCP analysis in combination with selective amplification is a rapid and sensitive procedure for the screening of the mutations in the glucocerebrosidase gene of patients with Gaucher disease.

Base Sequence↗
PubMed1992

Transient, unilateral, isolated hypoglossal nerve palsy.

We report a boy with isolated hypoglossal nerve palsy that recovered within twelve weeks. Investigations of the cervix, base of the skull, medulla and hypoglossal nerve by CT-scan and MRI did not show any abnormal findings. There are a few reports concerning isolated unilateral hypoglossal nerve palsy with benign course. Although we could not establish the cause of our patient's disease, an awareness of this condition should save such patients from unnecessary invasive studies.

Child↗
PubMed1992

Novel procedure for measuring psychosine derivatives by an HPLC method.

We developed a sensitive and simple method to determine galactosylsphingosine and glucosylsphingosine as a 4-fluoro-7-nitrobenzofurazan autofluorescent compound, using HPLC equipped with a Showdex sugar column. Amounts of galactosylsphingosine were successfully measured in the picomole range. This novel procedure is more stable and simpler than the previous method using o-phthalaldehyde. It was applied to tissues from the twitcher mouse, an animal model of human globoid cell leukodystrophy. The amount of galactosylsphingosine was 34-102 micrograms/kg of wet tissues in control cerebrum and cerebellum, whereas in twitcher mice the range was 2,251-4,228 micrograms/kg of wet tissues. The psychosine concentration was also increased in the liver and kidney of twitcher mice, respectively, 1,513 micrograms and 1,106 micrograms/kg of wet tissue (normal liver, 125 micrograms; normal kidney, 74 micrograms/kg of wet tissue). This novel procedure is useful for the pathochemical evaluation of lysosphingolipids in various sphingolipidoses as well as in other neuropathological and cellular conditions.

4-Chloro-7-nitrobenzofurazan↗
PubMed1992

In vivo action of activin-A on pituitary-gonadal system.

Activin, a dimer of the beta-subunits of inhibin, has been found to stimulate FSH secretion from the cultured pituitary cells. However, in vivo action of activin is poorly elucidated. Daily sc injections of 40 micrograms activin-A over a period of 1-3 days to intact immature female rats caused a significant increase in serum FSH, inhibin, estradiol, uterine weight, and ovarian FSH receptors. Daily sc injections of 5 micrograms or 20 micrograms activin-A for 6 days caused a marked increase in ovarian weight and the development of large ovarian follicles. However, daily sc injections of 20 micrograms activin-A to hypophysectomized immature female rats for 3 days induced no significant changes in ovarian and uterine weight, serum inhibin, estradiol, and progesterone levels. Simultaneous injections of both activin-A and 5 IU PMSG induced a significant increase in ovarian and uterine weight, serum inhibin, and estradiol levels, compared to simultaneous injections of both vehicle and PMSG in the hypophysectomized immature female rats. These results demonstrate that activin-A induces not only an increase of FSH secretion from the pituitary but also a direct autocrine or paracrine ovarian stimulation resulting in an increase of the number of ovarian FSH receptors and ovarian and uterine weight, as well as an increase in the level of inhibin and estradiol secretion from the ovary.

Activins↗