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T Ichimura

Publications and source records attributed to T Ichimura.

At least 37 records · Page 2Linked to original sources
PubMed1989

Concurrent poststreptococcal acute glomerulonephritis and Schönlein-Henoch purpura.

A 5-year-old Japanese boy developed concurrent poststreptococcal acute glomerulonephritis (PSAGN) and Schönlein-Henoch purpura (SHP). An elevated titer of ASK on admission confirmed the preceding streptococcal infection. Arthritis of the left knee and petechiae on admission were regarded as features of SHP. The presence of SHP was further confirmed by the pathological finding of leukocytoclastic vasculitis in the skin. PSAGN was strongly suspected due to the findings of microscopic hematuria and hypocomplementemia in the acute phase. The concurrence of SHP and PSAGN suggests similar underlying pathophysiological processes as poststreptococcal sequelae. At the height of the illness, peripheral blood lymphocyte subset analysis showed a marked increase in the suppressor inducer T subset and a reciprocal decrease in the helper T subset. This alteration in T lymphocyte subsets was regarded as indicative of the immunological derangement in this patient.

Child, Preschool↗
PubMed1989

Five cases of autoimmune neutropenia in infancy or early childhood.

Five cases of chronic neutropenia which developed mainly in infancy were investigated and followed up for 5 to 34 months. Antineutrophil antibody levels were assayed by the direct and indirect immunofluorescence methods using flow cytometry. Selective neutropenia, myeloid hyperplasia and/or maturation arrest of myeloid series cells in the bone marrow, and the demonstration of antineutrophil antibody in the sera and on autologous neutrophils, indicated that the neutropenias involved were autoimmune in nature. Two cases exhibited spontaneous recovery 12 and 14 months respectively after the diagnosis, with concomitant marked decreases in antineutrophil antibody levels. Our study of these five cases supports the view that this disorder may be a clinical entity with a relatively consistent clinical presentation and course. Within this framework of the disorder, however, a clear heterogeneity in clinical presentation and course was also noted in our cases. Clinical severity in this disorder may be enhanced by arrested maturation of myeloid series cell in the bone marrow.

Agranulocytosis↗
PubMed1989

Chemistry and cell biology of neuron- and glia-specific proteins.

Studies of proteins specific to a certain type of cell are of general interest because these proteins may be involved in the determination of morphological and functional characteristics of the cell. In the nervous tissue, many "neuron-specific" and "glia-specific" proteins have been identified by various biochemical and immunohistochemical means and their relationships to cell functions have been studied. This paper briefly reviews our studies on the chemical and cell-biological aspects of the neuron- and glia-specific proteins, with special reference to the 14-3-3 protein and the S100 protein. Our studies suggest that glial protein S100 may be involved in the regulation of cell growth and differentiation, while neuronal protein 14-3-3, in the regulation of serotonin and catecholamine biosynthesis in neurons and other monoamine-synthesizing cells.

14-3-3 Proteins↗
PubMed1989

Induction of HLA-DQ antigen expression on a human promyelocytic leukemia cell line HL-60.

A variant strain of HL-60, which is positive for HLA-DR antigen, was induced to express HLA-DQ antigen following treatment with phorbol esther. It was preceded by cell cycle arrest in the G1 phase and was accompanied by augmented phagocytosis. This differential expression of HLA class II antigens on this subline may contribute to understanding the functional role of HLA class II antigens in the hematopoietic differentiation of macrophage cells.

Cell Cycle↗
PubMed1989

[Using specific radioimmunoassay for guinea pig VIP (GP VIP), immunoreactive GP VIP levels in respiratory tract tissue of normal and airway-allergic guinea pigs].

Vasoactive intestinal polypeptide (VIP) has recently received widespread attention with respect to its control of airway constriction, and is now regarded as the most promising candidate as a neurotransmitter for nonadrenergic noncholinergic inhibitory nerves in the airway. A specific system of radioimmunoassay (RIA) was devised to measure guinea pig VIP (gp VIP) concentration in airway tissue. An antiserum, R 550, was obtained by immunizing rabbits with newly synthesized gp VIP. The detectable VIP concentration was assessed to be 10 fmol/tube with the RIA system. The concentration of gp VIP in the respiratory tract tissue of normal guinea pigs was 0.04-0.22 pmol/g wet weight of tissue. The VIP level was highest in the trachea, in contrast to lower levels in both the major bronchus and lower lung. After being passively sensitized with ovalbumin, the experimental guinea pigs were exposed to the same antigen. After three minutes, as the expiration time was prolonged and the respiratory resistance increased, the immunoreactivity in the trachea and the major bronchus was significantly higher than the pre-exposure levels. After six hours, however, they returned to the original levels except in the lower lung where the level was constant throughout the respiratory change. As described above, the possibility of controlling airway constriction by VIPergic nerve in immediate-type allergic reactions is suggested by our findings.

Amino Acid Sequence↗
PubMed1988

[The measurement of plasma-free testosterone in normal menstrual females, pregnant females, post menopausal females and vulvar dystrophy].

It is considered that plasma-free testosterone is a bioactive androgen in blood and is more reflective in androgenicity than plasma total testosterone. We measured plasma-free testosterone by dialyzable method in normal menstrual females, pregnant females, post menopausal females and vulvar dystrophy. The values of plasma total testosterone (T), fractional free testosterone (%FT) and plasma-free testosterone (free T) were 0.61 +/- 0.27 (mean +/- SD)ng/ml, 1.19 +/- 0.34% and 0.61 +/- 0.20 ng/kl in the follicular phase of normal menstrual females (n = 25), and 0.57 +/- 0.23 ng/ml, 1.29 +/- 0.46% and 0.56 +/- 0.35 ng/dl in the luteal phase of normal menstrual females (n = 24), respectively. The values in both phases showed no differences from each other. In post menopausal females (n = 18), the concentration of T (0.36 +/- 0.27 ng/ml) and free T (0.52 +/- 0.12 ng/dl) was significantly lower (T: P less than 0.01, free T: P less than 0.05) than that in normal menstrual females. However, %FT in post menopausal females (1.37 +/- 0.12%) was not different as compared with that in normal menstrual females. In pregnant females (n = 2) of second and third trimester, T (0.53 +/- 0.07 ng/ml) was not different as compared with that in normal menstrual females, but %FT (0.67 +/- 0.45%) and free T (0.33 +/- 0.23 ng/dl) were significantly lower (P less than 0.05) than in normal menstrual females. In vulvar dystrophy, lichen sclerosus (n = 19) and hyperplastic dystrophy without atypia (n = 12) were measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Structural components in the synaptic cleft captured by freeze-substitution and deep etching of directly frozen cerebellar cortex.

Structural components in the synaptic cleft were examined in cerebellar excitatory synapses by conventional electron microscopy and by rapid freezing followed by freeze-substitution or deep etching. Two transverse components and one parallel element were identified in the clefts of rapidly frozen and freeze-substituted synapses: (i) bridging fibrils, 4-6 nm in diameter, that span the cleft; (ii) columnar pegs, 4-6 nm wide and 8-15 nm high, projecting from the postsynaptic surface; and (iii) intervening fine fibrils running parallel to the apposed synaptic membranes. These were more clearly visible in deep-etched synapses, although the postsynaptic pegs were difficult to distinguish from intramembrane particles in the cross-fractured postsynaptic membranes. Deep etching also revealed other fibrils on the cytoplasmic surface of the postsynaptic membrane. These appear to contact the membrane surface or the intramembrane particles. Freeze-substituted materials also displayed the fibrillar components in the postsynaptic dense fuzz, but failed to display the presynaptic dense projections typically observed in thin sections or deep-etched replicas of the conventionally fixed materials. The bridging fibrils are likely to play a mechanical role in holding the synapse together, while the short pegs may be integral parts of the receptor molecules.

Animals↗
PubMed1988

Myoblast-mediated fusion-injection: a new technique for introduction of macromolecules specifically into living skeletal muscle cells.

A new technique for the introduction of macromolecules specifically into living skeletal muscle cells has been developed by a modification of the red blood cell ghost-mediated fusion-injection technique [M. Furusawa (1980) Int. Rev. Cytol. 62, 29-67]. Fluorescein-labeled bovine serum albumin (FITC-BSA) was introduced into chicken skeletal muscle myoblasts by the human red blood cell-mediated fusion-injection method in the presence of polyethylene glycol. Myoblasts loaded with FITC-BSA were then purified by a fluorescence cell sorter and cocultured with myotubes. Specific cell fusion between myoblasts and myotubes occurred under normal culture conditions and BSA was successfully introduced into living myotubes. This technique may provide a new method not only for the study of a given macromolecule's function in living muscle cells but also for therapeutic purposes such as muscle-specific drug delivery.

Animals↗
PubMed1988

Molecular cloning of cDNA coding for brain-specific 14-3-3 protein, a protein kinase-dependent activator of tyrosine and tryptophan hydroxylases.

The 14-3-3 protein is a family of acidic proteins present exclusively in the brain and is believed to have a function in monoamine biosynthesis because of its ability to activate tyrosine hydroxylase and tryptophan hydroxylase in the presence of Ca2+/calmodulin-dependent protein kinase type II. In this study, we resolved bovine brain 14-3-3 protein into seven polypeptide components by means of reversed-phase chromatography and determined the amino acid sequence of one of these components (eta chain) by cloning its cDNA from a bovine cerebellum cDNA library. The eta-chain mRNA is 1.8 kilobases long and encodes a polypeptide of 246 amino acids and Mr 28,221. Computer-assisted analysis of the sequence indicates that the eta chain exhibits no internal sequence repeats, nor does it have significant sequence similarity to other proteins with known amino acid sequence. However, the eta chain appears to consist of two structural regions that are distinguishable in their clearly different charge characteristics: the almost neutral amino-terminal region and the strongly acidic carboxyl-terminal region. The structural features of the eta chain and the domain organization of tyrosine and tryptophan hydroxylases suggest that the 14-3-3 protein binds to the regulatory domain of the phosphorylated hydroxylases through its acidic carboxyl-terminal region and activates the hydroxylases by inducing an active conformation.

14-3-3 Proteins↗
PubMed1987

Brain 14-3-3 protein is an activator protein that activates tryptophan 5-monooxygenase and tyrosine 3-monooxygenase in the presence of Ca2+,calmodulin-dependent protein kinase II.

We have found that the 14-3-3 protein, an acidic neuronal protein, is substantially identical to the 'activator' protein [(1981) J. Biol. Chem. 256, 5404-5409] that activates tryptophan 5-monooxygenase and tyrosine 3-monooxygenase in the presence of Ca2+, calmodulin dependent protein kinase II. This finding is based on the remarkable similarity of both these proteins in physicochemical, biochemical and immunochemical properties, as well as on detection for the 14-3-3 protein of an activator activity towards tryptophan 5-monooxygenase. The result suggests that the 14-3-3 protein plays a role in the regulation of serotonin and noradrenaline biosynthesis in brain.

14-3-3 Proteins↗
PubMed1986

Identification of the C-terminal portion of a protein by comparative peptide mapping.

A method is presented for the simple identification of C-terminal fragment of proteins. The method consists of (i) C-terminal processing of a protein by carboxypeptidase and (ii) comparative peptide mapping of the intact and carboxypeptidase-excised protein after fragmentation by endoproteinase or by chemical cleavage. The peptide mapping was performed by means of high-performance reversed-phase chromatography, where the C-terminal fragment was identified as a peptide peak that was lost or decreased in the carboxypeptidase-excised protein. The C-terminal sequence of the protein could be then determined by sequential Edman degradation of the C-terminal fragment collected from the peptide mapping chromatography. The sensitivity of the method depends solely on the peptide detection and subsequent Edman degradation, currently available techniques of which require a nanomole to subnanomole quantity of protein. The present method can be coupled with conventional carboxypeptidase technology because it utilizes a protein portion remaining after carboxypeptidase digestion while released amino acids are needed in the conventional technique. The method would be particularly valuable in finding a gene probe site for a RNA message coding for the C-terminal portion of a molecule.

14-3-3 Proteins↗
PubMed1986

Acoustoelectric technique for assessing the mechanical state of the dental implant-bone interface.

A simple technique is described for in vivo assessing the interfacial rigidity between a dental root implant and the bone surrounding it. The method is based on estimating the frequency (10 to 150 KHz) and amplitude of the vibration of the implant induced by a small pulsed force. Application of the force to the implant and detection of the vibrational signal from the implant are performed by lightly touching it with two fine needles connected with piezoelectric elements. A distinct signal difference observed in animal tests of bioactive implant and nonbioactive one is shown to well agree with that obtained from corresponding ex vivo models.

Animals↗
PubMed1986

Fine-structural study of the pineal body of the monkey (Macaca fuscata) with special reference to synaptic formations.

Various types of synaptic formations on pinealocytes and pineal neurons were found in the pineal body of Macaca fuscata. Axo-somatic synapses of the Gray type-II category were detected on the pinealocyte cell body. Gap junctions and ribbon synapses were observed between adjacent pinealocytes. About 70 nerve-cell bodies were detected in one half of the whole pineal body bisected midsagittally. They were localized exclusively deep in the central part. When examined electron-microscopically, they were found to receive ribbon-synapse-like contacts from pinealocytic processes. They also received synaptic contacts of the Gray type-I category on their dendrites, and those of the Gray type-II category on their cell bodies from nerve terminals of unknown origin. All these synapse-forming axon terminals contained small clear vesicles. Thus, the pineal neurons of the monkey, at least in part, are suggested to be derived from the pineal ganglion cells in the lower vertebrates and not from the postganglionic parasympathetic neurons. The functional significance of these observations is discussed in relation to the innervation of the pineal body of the monkey.

Animals↗
PubMed1985

Visualization of the cerebrospinal fluid drainage into the Galen's vein.

Arachnoid granulations are not always present in lower mammals and primate newborns. In order to visualize the route for the cerebrospinal fluid (CSF) to drain into the venous system, horseradish peroxidase (HRP) was injected into the lateral ventricle or cisterna cerebellomedullaris of the mouse and rat. From 30 to 60 min after the commencing of a slow infusion for 15-30 min of 0.05-0.1 ml solution containing 10-20 mg HRP, the mouse, whose skull had been exposed, was dropped into cold acetone at dry ice temperature; other animals were fixed by perfusion with aldehyde solution. The frozen head was dissected in a cryostat kept at -18 degrees C to remove the skull, but leave the dura mater and the falx cerebri. The brain with meninges was cut into 30-45 microns sagittal sections in the cryostat, and processed for peroxidase reaction. The perfusion-fixed brains were used for scanning electron microscopy and for electron microscope observation of the tracer. The reaction product was found within fenestrated venous capillaries of the choroid plexus. The route for the HRP in the CSF to drain into the sinus rectus via the vena choroidea and vena cerebri magna was directly visualized in the mouse.

Animals↗