Search PubMed⌕ Search

Biomedical subjects

E Yamada

Publications and source records attributed to E Yamada.

At least 91 records · Page 5Linked to original sources
PubMed1994

Decreased immunoreactivity of platelet-derived growth factor B chain-like peptide after axotomy in the dorsal motor nucleus of the vagus nerve.

Platelet-derived growth factor-B chain (PDGF-B) and B chain-specific beta receptor (PDGF-R) were investigated immunohistochemically in the dorsal motor nucleus of the vagus nerve and hypoglossal nucleus after axotomy using antibodies raised against synthetic polypeptides. PDGF-B and PDGF-R immunoreactivity were observed in nerve cell bodies contralateral to the axotomized nerve in both vagal (degenerative) and hypoglossal (regenerative) nuclei. The immunoreactivity for PDGF-B antibody persisted until day 28 after axotomy in the hypoglossal neurons, while that in many neurons in the vagal nucleus diminished after day 3. In the severed vagal nucleus some of the axotomized neurons showed no immunoreactivity for PDGF-B chain, and these changes preceded the decrease in neuronal numbers in the vagal nucleus. The immunoreactivity for PDGF-R antibody showed no marked change in either the vagal or hypoglossal nucleus until day 28 after axotomy. These findings suggest that the decrease in PDGF-B immunoreactivity is not due to a non-specific depletion of cytoplasmic protein in the severed vagal neurons. PDGF, taken up by the nucleus and bound to chromatin, has been reported to exert direct effects on the enhancement of transcription and synthesis of RNA. The decrease in level of PDGF-B chain in the vagal neurons seems to cause the reduction of RNA and protein synthesis, resulting in neuronal degeneration.

Animals↗
PubMed1994

Specific expression of type II protein kinase c after axotomy in the dorsal motor nucleus of the vagus nerve and the hypoglossal nucleus.

Protein kinase C (PKC) and growth-associated protein-43 (GAP-43) were investigated immunohistochemically in the dorsal motor nucleus of the vagus nerve and the hypoglossal nucleus after axotomy using monoclonal antibodies against type I, II and III PKC and GAP-43. In the control side of both nuclei, anti-type I and II PKC weakly stained neuronal cell bodies, while anti-type III PKC did not show any reaction with neurons. In the axotomized side of both nuclei, anti-type II PKC antibody intensely stained affected nerve cell bodies as well as plasma membrane. Some of the severed neurons showed intensified reactions for both anti-type II PKC and anti-GAP-43 antibodies in the serial sections. These findings suggest that axotomy increases the type II PKC of the severed neurons, and type II PKC seems to phosphorylate some protein, such as GAP-43, and plays some role in the retrograde neuronal reaction.

Animals↗
PubMed1994

Causative role of lysosomal enzymes in the pathogenesis of cerebral lesions due to brain edema under chronic hypertension.

In order to clarify the role of lysosomal enzymes in the developmental mechanisms of cerebral lesions under chronic hypertensive conditions, we histochemically and biochemically investigated acid phosphatase, N-acetyl-beta-glucosaminidase, and cathepsin B in the cerebral cortex and subcortical white matter in stroke-prone spontaneously hypertensive rats (SHRSP). Histochemical investigation showed that SHRSP had an increased number of cells with positive reaction to these enzymes in the edematous cortex and degenerated subcortical white matter. The cells with positive reaction were made up of reactive astrocytes and microglias. The activities of all enzymes in the aged SHRSP were higher than those in normotensive rats, the differences being significant at 24 weeks of age. The present study suggests that chronic hypertension or chronic edema causes increased activities of lysosomal enzymes in the cerebral cortex and subcortical white matter, and that the activated lysosomal enzymes take part in the developmental mechanisms of cystic formation as well as the diffuse degeneration of the white matter.

Acetylglucosaminidase↗
PubMed1994

Expression of basic fibroblast growth factor in astrocytes at the site of cerebral lesions and edematous areas under chronic hypertension.

In an attempt to obtain information about changes of the basic fibroblast growth factor (bFGF) in the brain under chronic hypertensive condition, we studied immunohistochemically the distribution of bFGF in the brain of stroke-prone spontaneously hypertensive rats (SHRSP). In the control normotensive rats, only weak immunoreactivity for bFGF was demonstrated in nerve cells and some astrocytes. In SHRSP marked immunoreactivity was demonstrated in the densely packed reactive cells, particularly astrocytes, in and around cerebral lesions. Slightly increased reaction for bFGF was found in the nerve cells around lesions. Astrocytes in the white matter also showed immunoreactivity for bFGF, the localization of which corresponded very well with the site of edema. This finding indicates the possibility that brain edema expresses bFGF in astrocytes and possibly in nerve cells.

Animals↗
PubMed1994

Increased basic fibroblast growth factor immunoreactivity in the brain of stroke-prone spontaneously hypertensive rats.

To obtain information about changes of basic fibroblast growth factor (bFGF) in the brain under a chronic hypertensive condition, we immunohistochemically studied the distribution and level of bFGF in the brain of stroke-prone spontaneously hypertensive rats (SHRSPs). The advanced cerebral lesions in SHRSPs demonstrated massive bleeding, cavity formation and diffuse degeneration of the white matter, whereas the early changes were petechiae, edema and massive glial accumulation around fibrin deposition containing necrotized microvessels. In the control normotensive rats, immunoreactivity for bFGF was demonstrated in nerve cells, especially in selective neuronal populations, ependymal cells and epithelial cells of the choroid plexus, while there was almost no reactivity in astrocytes. In SHRSPs, on the other hand, there was marked immunoreactivity in the densely accumulated reactive cells, particularly astrocytes, in and around cerebral cortical lesions. Slightly increased reaction for bFGF was found in the nerve cells around lesions. Astrocytes in the subcortical white matter on both ipsi- and contralateral sides of the cortical lesion also showed immunoreactivity for bFGF. The location of increased bFGF expression in SHRSPs corresponded very well with the site of extravasated plasma fluid demonstrated by anti-fibrinogen antibody. Electron microscopically, bFGF was shown in astrocytes along the rough endoplasmic reticulum, suggesting that the growth factor was produced in the cells and not taken up from the surroundings. These findings indicate the possibility that edema and the simultaneously generated free radicals or some extravasated plasma components express bFGF in astrocytes and probably in nerve cells, and that the thus expressed bFGF plays some role in the sequence of developmental events of hypertensive cerebral lesions.

Animals↗
PubMed1994

Increased expression of phosphotyrosine after axotomy in the dorsal motor nucleus of the vagus nerve and the hypoglossal nucleus.

To investigate the role of tyrosine kinase underlying glial cell proliferation after axotomy, the localization of phosphotyrosine was studied immunohistochemically in the dorsal motor nucleus of the vagus nerve and the hypoglossal nucleus after nerve transection in adult rats. An anti-phosphotyrosine antibody weakly stained the cytoplasm of the neurons and some glial cells on the control side of both nuclei, while preferentially staining the plasma membrane of perineuronal microglial cells and neurons weakly on the severed side 2 days after axotomy and intensely between 3 and 7 days. Some of the microglial cells reacted positively with both anti-bromodeoxyuridine and anti-phosphotyrosine antibodies, suggesting that tyrosine kinase is involved in microglial cell proliferation. Proliferation of numerous microglial cells was observed in the severed nuclei between 2 and 4 days after axotomy, while only a few were detected on days 5 and 7. These findings suggest that tyrosine kinase is involved in not only the proliferation of perineuronal microglial cells but also in some retrograde neuronal reactions such as differentiation and regeneration.

Animals↗
PubMed1994

Scanning electron microscopy of acinar cells of rat submandibular salivary glands.

1. The submandibular salivary gland of rats was observed by high-resolution scanning electron microscopy employing the aldehyde-osmium-DMSO-osmium method. 2. The intracellular membranous components and sponge-like structures of basement membrane containing the fine collagen fibrils of acinar cells were clearly identified in three-dimensional images. The granular endoplasmic reticulum and Golgi apparatus showed the luminal surface. The mitochondria were small, ranging in diameter from 0.3 to 0.5 microns, and revealed their cristae. The secretory granules ranged in diameter from 0.3 to 1.4 microns. Ribosome granules were attached to the surfaces of cisterns, and measured 20 to 25 nm in diameter. 3. The contact areas between the acinar cells revealed numerous cytoplasmic protrusions. In the striated duct cells, the mitochondria were arranged vertically and surrounded by basal infoldings of the plasma membranes. At high magnification, the mitochondrial cristae were visualized in their three-dimensional characteristics.

Animals↗
PubMed1994

[A case of vertebral metastasis revealed by incomplete spinal analgesia for cesarean section].

A 36-year-old woman was scheduled for Cesarean section under spinal anesthesia. She was a carrier of hepatitis-B-virus and diabetic. She was complaining of low back pain. Spinal anesthesia was performed in the left lateral decubitus position. Because lumbar puncture in the midline was difficult, left paramedian approach was tried. Then she began to complain of right leg pain. Another attempt was made at other site, but her pain was not relieved. After confirming drop of blood-tinged cerebrospinal fluid, 0.3% dibucaine 2.0 ml was injected. Sensory anesthesia was assessed by pin-prick, but anesthesia was not effective. Then epidural catheter was inserted at Th12-L1 using median approach. She received 1.0% lidocaine 15 ml. However, sensory anesthesia was insufficient (Th4-Th12). Therefore O2-N2O was administered in addition to regional anesthesia. After the delivery, she still complained of low back pain. Later examination revealed metastatic bone tumor of L2 from hepatoma. This case suggests that in a patient with such incomplete spinal or epidural anesthesia and neurological finding, vertebral metastatic tumor should be ruled out.

Adult↗
PubMed1993

Haemopoietic activity associated with biglycan like proteoglycan.

One of the monocytic cell colony stimulating factors produced by thymic myoid cells, a 100 kDa factor, was purified by reversed phase HPLC and found to be homologous to the secreted form of proteoglycan 1 (biglycan) core protein. This biglycan associated colony stimulating factor did not carry an immunological motif of macrophage colony stimulating factor (M-CSF), but predominantly stimulated the proliferation and differentiation of monocytic lineage cells from bone marrow cells, nonadherent thymic cells and peritoneal exudate cells.

Amino Acid Sequence↗
PubMed1993

Different stability of neurofilaments for trypsin treatment after axotomy in the dorsal motor nucleus of the vagal nerve and the hypoglossal nucleus.

In an attempt to obtain information about changes of neurofilaments in motor neurons after axotomy, we immuno-histochemically investigated the accumulated neurofilaments in the dorsal motor nucleus of the vagal nerve, which shows nerve cell loss and degenerative changes after axotomy, and in the hypoglossal nucleus, which shows regenerative changes. Affected neurons in the hypoglossal nucleus showed intensified immunoreactivities for neurofilament antibodies phosphorylated at the carboxy-terminal, and these reactions disappeared with trypsin treatment. Accumulated neurofilaments in the neuronal perikarya in the dorsal motor nucleus of the vagal nerve and axons in brain stem also showed intensified immunoreactivities for the same antibodies, and these reactions remained positive after trypsin treatment. Anti-ubiquitin antibody preferentially stained accumulated neurofilaments in the affected vagal neurons, while no reaction was found in the affected hypoglossal neurons. Phosphorylated neurofilaments in hypoglossal neurons are vulnerable to trypsin treatment probably because of the blocking of polymerization or the disassembly of neurofilaments due to amino-terminal phosphorylation. In vagal neurons, the deteriorated amino-terminal phosphorylation or hyperphosphorylation at the carboxy-terminal seems to cause the cross-linkage and polymerization of neurofilaments, and densely packed polymerized neurofilaments probably fail in axonal transport resulting in nerve cell degeneration and death in the dorsal motor nucleus.

Animals↗
PubMed1993

The possible role of lysosomal enzymes in the pathogenesis of hypertensive cerebral lesions in spontaneously hypertensive rats.

In an attempt to clarify the role of lysosomal enzymes in the developmental mechanisms of cerebral lesions under chronic hypertensive conditions, we biochemically investigated the activities of acid phosphatase (AcPase), N-acetyl beta-glucosaminidase (NAGase) and cathepsin B (CathB) in the cerebral cortex and subcortical white matter in stroke-prone spontaneously hypertensive rats (SHRSPs). We also investigated enzyme-histochemically the activities of AcPase and NAGase, and immunohistochemically the distribution of CathB. The activities of all enzymes tended to increase with advancing age. The enzyme activities in the aged SHRSPs were in general higher than those in normotensive rats, the differences being significant at 24 weeks of age. Histochemical investigation showed that SHRSPs had an increased number of cells with positive reaction to these enzymes in the edematous cortex with and without vascular changes, and degenerated subcortical white matter. These cells with positive reaction were made up of reactively increased astrocytes and microglia. Neurons in the edematous area also showed slightly intensified enzyme activities. The present studies suggest that chronic hypertension or chronic edema due to hypertension causes increased activities of lysosomal enzymes in the cerebral cortex and subcortical white matter and, thus, that activated lysosomal enzymes may take part in the developmental mechanisms of cystic formation as well as the diffuse degeneration of the white matter.

Acetylglucosaminidase↗
PubMed1993

Variomatrix--a newly developed transesophageal echocardiography probe with a rotating matrix biplane transducer. Technological aspects and initial clinical experience.

The recently developed multiplane transesophageal echocardiography (TEE) probes cannot provide real-time synchronous biplane imaging. We have developed a new "Variomatrix" probe that combines the advantages of the rotating mechanism of the multiplane probe with the capability of providing simultaneous, side-by-side imaging. Its advantages are: (1) easy manipulation to obtain the optimal planes; (2) avoidance of excessive movement of the probe inside the esophagus; (3) assessment of oblique planes that are not viewed with the usual biplane probe; (4) better understanding of the continuity of structures by the simultaneous, side-by-side biplane, rotating images, providing clearer three-dimensional conception; and (5) shorter examination time by providing a 180 degrees imaging range by rotating the transducer just 90 degrees .

Echocardiography, Doppler↗
PubMed1992

High-resolution scanning electron microscopic study of the mouse submandibular salivary gland.

The submandibular gland of the mouse was studied by high-resolution scanning electron microscopy, using the osmium-dimethylsulfoxide-osmium method. The three-dimensional structures of the intracellular membranous organelles of acinar cells were clearly revealed. The luminal surface of cisterns of the granular endoplasmic reticulum and Golgi apparatus exhibited particles of 8-15 nm in diameter. The secretory canaliculi presented short microvilli which were irregularly arranged. The striated duct cells were characterized by rich mitochondria arranged vertically in the basal portion. The lamellar mitochondrial cristae were noted in three-dimensional images. The luminal surface extended short microvilli, while that of the excretory duct cell presented complicated microplicae. The capillary endotheliocytes showed a few short microvilli, and their fenestrated areas were bordered by cytoplasmic crests. Fenestrae were 50-80 nm in diameter and showed a plug in their center. The basement membranes of the acini and capillaries showed a spongy structure with various strands and meshes. Collagenous fibrils crisscrossed on their surface.

Animals↗
PubMed1992

"Pored-domes" of the fenestrated endotheliocyte of the glomerular and peritubular capillaries in the rodent kidney.

The fenestrated endotheliocyte of peritubular and glomerular capillaries in rat and mouse kidneys were observed with SEM and TEM. In the glomerular capillary, so-called "pored-domes" were found not only at the fenestrated areolae but also at the nuclear region of the endotheliocyte. At the region between filtration surface and nuclear region, they accumulated to construct a sponge-like structure. The endotheliocyte of peritubular capillary also showed small "pored-domes". The size and morphology of the pores in the "pored-domes" of glomerular and peritubular capillaries were similar to those of areolae fenestratae of the respective capillary. Based on the findings, we assumed that pored-domes and the sponge-like structure are the reservoir for the fenestrated area of the endotheliocyte to accommodate the rapid expansion of capillary lumen.

Animals↗