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Biomedical subjects

C Ide

Publications and source records attributed to C Ide.

At least 55 records · Page 3Linked to original sources
PubMed1997

Nedd5, a mammalian septin, is a novel cytoskeletal component interacting with actin-based structures.

The mouse Nedd5 gene encodes a 41.5-kD GTPase similar to the Saccharomyces and Drosophila septins essential for cytokinesis. Nedd5 accumulates near the contractile ring from anaphase through telophase, and finally condenses into the midbody. Microinjection of anti-Nedd5 antibody interferes with cytokinesis, giving rise to binucleated cells. In interphase and postmitotic cells, Nedd5 localizes to fibrous or granular structures depending on the growth state of the cell. The Nedd5-containing fibers are disrupted by microinjection of GTPgammaS and by Nedd5 mutants lacking GTP-binding activity, implying that GTP hydrolysis is required for its assembly. The Nedd5-containing fibers also appear to physically contact actin bundles and focal adhesion complexes and are disrupted by cytochalasin D, C3 exoenzyme, and serum starvation, suggesting a functional interaction with the actin-based cytoskeletal systems in interphase cells.

3T3 Cells↗
PubMed1997

Castleman's disease in the neck: MRI.

We describe a case of Castleman's disease in a 8-year-old-boy who presented with a slowly growing mass in the upper neck. MRI showed a well-defined homogeneous mass with nonspecific signal features. Unusual features were a kidney-bean shape and the deep location in the suprahyoid region, the mass originating in the left retropharyngeal space.

Biopsy↗
PubMed1997

Developmental changes in the subcellular localization of R-cadherin in chick retinal pigment epithelium.

It has been reported that in the chick embryonic retina, N-cadherin first appears at the very early stages and is subsequently substituted by R-cadherin at the middle to late stages of development. To examine the role of R-cadherin in the morphogenesis of chick retinal pigment epithelium (RPE), the distribution of this adhesion molecule was studied by immunofluorescence cytochemistry and immunoelectron microscopy from embryonic day (E) 6 to hatching. R-cadherin immunoreactivity was detected at E6, and was strongest at E12-13. During these stages, R-cadherin was expressed uniformly on the lateral plasma membranes of RPE cells in contact with each other. Thereafter, R-cadherin immunoreactivity was markedly decreased, with intense immunoreactivity restricted to zonulae adherentes in latero-apical regions at E16. R-cadherin immunoreactivity was no longer detectable in the newly hatched chick RPE, even though morphologically well developed zonulae adherentes were present in latero-apical regions. No immunoreactivity was detected on the apical side facing the neural retina or on the basal side facing the basal lamina at any stage of development. These findings indicate that R-cadherin plays an important role as a major cadherin subtype in the morphogenesis of chick embryo RPE, and is involved initially in non-specific cell-cell adhesions, and subsequently in the formation and maintenance of developing zonulae adherentes.

Animals↗
PubMed1997

Experimental syringomyelia: late ultrastructural changes of spinal cord tissue and magnetic resonance imaging evaluation.

BACKGROUND: In human hydrosyringomyelia and in the late stage of experimental syringomyelia, the spinal cord tissue adjacent to the syrinx is exposed to a similar pathophysiologic condition. We investigated the ultrastructural changes in the late stages of kaolin-induced syringomyelia, and in addition, we presented magnetic resonance imaging (MRI) findings of the cervicomedullary junction and syrinx, and the nature of edema in the spinal cord of this experimental model. METHODS: Syringomyelia was induced in rabbits by intracisternal injection of kaolin. MRI was performed at 6 weeks, and 6 and 12 months following injection, and the animals were killed by transcardial perfusion of formaldehyde solution and examined by transmission electron microscopy. Evans blue was injected intravenously in six rabbits, 6 weeks and 12 months following kaolin injection and was examined by confocal laser scanning microscopy. RESULTS: MRI showed that the syrinx communicated with the fourth ventricle in most animals. Demyelination of varying degrees and slight edematous change were seen in the perisyrinx white matter. No extravasation of Evans blue was seen by confocal microscopy. Abundant astrocytic proliferation with a large number of glial filaments was seen at the margin of the syrinx and between the axons in the perisyringeal region. The perivascular space enlargement occurred in both the gray and white matter. The endothelial junctions appeared intact. Regenerating axons and remyelination by oligodendrocytes were seen occasionally. CONCLUSIONS: The MRI confirmed the communication between the fourth ventricle and the syrinx. The ultrastructural changes were almost identical to those of the early stage syrinx, but the astrocytic proliferation was more severe, and the edema was less in the late stage. The perisyrinx edema appeared to be of the interstitial type, as in hydrocephalus. Axonal degeneration and demyelination continued with abortive attempt at regeneration and remyelination in the less edematous late stage, which might be the cellular basis for the persistence or worsening of clinical symptoms and signs in the chronic stage of syringomyelia even after surgical treatment.

Animals↗
PubMed1997

Remyelination in the rat dorsal funiculus following demyelination by laser irradiation.

Excimer laser (KrF excimer laser, 248 nm wavelength) was used to damage cellular components in the dorsal funiculus at the lumbar level (L2) of the rat spinal cord. An open lesion was not found at the irradiation site on the spinal cord. However, the cytological examination revealed that cellular components were damaged to the depth of 200-500 microm from the pial surface. The characteristic feature was that at the border of the lesion, many axons remained naked but intact after their myelin sheaths had been completely disintegrated. Such naked axons were subsequently remyelinated by mature or immature glial cells. Mature oligodendrocytes, while retaining their cytoplasmic processes connected with the myelin sheaths of unaffected axons, extended new cytoplasmic processes on nearby naked axons and made new myelin sheaths around them. In contrast, 7 days after the irradiation, numerous immature glial cells appeared in association with naked axons, and some of them were differentiated into oligodendrocytes forming thin myelin sheaths on naked axons. These findings suggest that demyelinated axons can cause the proliferation and probably dedifferentiation of the oligodendrocyte lineage. The use of lasers provides a unique experimental model of demyelination and remyelination in the central nervous system of adult mammals.

Animals↗
PubMed1997

Immunocytochemical distribution of Ca(2+)-independent protein kinase C subtypes (delta, epsilon, and zeta) in regenerating axonal growth cones of rat peripheral nerve.

In the peripheral nerve, regenerating axonal sprouts usually emanate at nodes of Ranvier, and extend as growth cones along the inner surface of Schwann cells and/or through Schwann cell columns in the distal nerve segment. In order to elucidate the significance of Ca(2+)-independent protein kinase C in nerve regeneration, localizations of delta, epsilon and zeta subtypes were examined immunocytochemically in sprouts and growth cones of regenerating axons, as well as in normal intact nerves in the rat sciatic nerve. In normal nerves, intense immunoreactivities of delta, epsilon and zeta subtypes were present in axons of both myelinated and unmyelinated fibres. Subcellularly, the distribution of these subtypes in the axoplasm was patchy, and discontinuous in the axolemma and subaxolemmal peripheral zones of myelinated nerves. Some thin myelinated axons showed no immunoreactivity for epsilon subtype. Schwann cells of both myelinated and unmyelinated fibres had moderate immunoreactivities for each subtype. In areas of nerve regeneration, axonal sprouts at nodes of Ranvier, and growth cones extending along Schwann cell basal laminae, had intense immunoreactivities for delta, epsilon and zeta subtypes which are distributed diffusely throughout the axoplasm, and on the entire axolemma. In the sprouts, immunoreactivity for epsilon subtype was strong on the axolemma, but weak or almost absent in the axoplasm. These data, together with those of our previous study, indicate that Ca(2+)-independent protein kinase C subtypes (delta, epsilon and zeta) have basically the same distribution patterns as those of Ca(2+)-dependent subtypes in sprouts and growth cones of regenerating axons, as well as in normal intact axons; albeit epsilon subtype is somewhat different in distribution and intensity from delta and zeta subtypes. It is suggested that Ca(2+)-independent subtypes are involved in maintaining growth cone activities along with the Ca(2+)-dependent subtypes.

Amino Acid Sequence↗
PubMed1997

Basic fibroblast growth factor promotes extension of regenerating axons of peripheral nerve. In vivo experiments using a Schwann cell basal lamina tube model.

Schwann cell basal lamina tubes serve as attractive conduits for regeneration of peripheral nerve axons. In the present study, by using basal lamina tubes prepared by in situ freeze-treatment of rat saphenous nerve, the effects of exogenously applied basic fibroblast growth factor (bFGF) on peripheral nerve regeneration was examined 2 and 5 days after bFGF administration. Regenerating axons were observed by light and electron microscopy using PGP9.5-immunohistochemistry for specific staining of axons. In addition, the localizations of bFGF and its receptor (FGF receptor-1) were examined by immunohistochemistry using anti-bFGF antibody and anti-FGF receptor-1 antibody, respectively. Regenerating axons extended further in the bFGF-administered segment than in the bFGF-untreated control segment. Electron microscopy showed that regenerating axons grew out unaccompanied by Schwann cells. Findings concerning angiogenesis and Schwann cell migration were very similar between the bFGF treated and control nerve segment. bFGF-immunoreactivity was not detected in the control nerve segment. In contrast, bFGF-immunoreactivity was detected on the basal lamina tubes as well as on the plasmalemma of regenerating axons facing the basal lamina in the bFGF treated nerve segment up to 5 days after administration, suggesting that exogenous bFGF can be retained in the basal lamina for several days after administration. FGF receptor was detected on the plasma membrane of regenerating axons where they abutted the basal lamina. These results indicate that bFGF could promote the extension of early regenerating axons by directly influencing the axons, but not via Schwann cells or angiogenesis.

Animals↗
PubMed1997

Distribution of plasmalemmal Ca(2+)-pump and caveolin in the corneal epithelium during the wound healing process.

PURPOSE: Caveolae are small plasmalemmal invaginations which are assumed to play various physiological functions. In the present study, distribution of two caveolae-specific proteins, the plasmalemmal Ca(2+)-pump and caveolin, was examined in the corneal epithelium in the normal state and after artificial wounding. METHODS: A central epithelial ablation was made in the mouse cornea by a razor blade. After various intervals, the corneas were excised, fixed, and rapidly frozen. The specimens were subjected to immunofluorescence microscopy and immunoelectron microscopy, using antibodies against the plasmalemmal Ca(2+)-pump or caveolin. RESULTS: In the normal corneal epithelium, both plasmalemmal Ca(2+)-pump and caveolin were observed along the cell surface by immunofluorescence microscopy, and were localized to caveolae by immunogold electron microscopy. In the regenerating epithelium, 12-18 h after injury, plasmalemmal Ca(2+)-pump was seen as many dots in the cytoplasm by immunofluorescence microscopy; in contrast, caveolin persisted along the cell surface. Immunoelectron microscopy revealed that the labeling for the plasmalemmal Ca(2+)-pump was located around membranous structures in the cytoplasm and was scarce along the plasma membrane, while caveolin remained in caveolae. The Ca(2+)-pump regained normal distribution when the wound was closed. By quantitation in electron micrographs, the number of caveolae per unit plasma membrane length was found to be decreased in the wounded corneal epithelium. CONCLUSIONS: The present results indicate that caveolae undergo compositional modification during the wound healing process of the corneal epithelium. Considering putative caveolar functions, the phenomenon may be related to possible fluctuations of the intracellular Ca(2+)-concentration in the regenerating epithelium.

Animals↗
PubMed1997

Chronic sinusitis: the role of imaging.

In recent years, routine endoscopic examination of the nose and advances in medical imaging have led to a better understanding of the pathophysiology of chronic sinusitis and the development of "FESS". The CT san of the sinuses have superseded the conventional standard radiography in the evaluation of the paranasal sinuses as it offers more precise anatomic information to the surgeon on the complex anatomy of the sinus cavities and their drainage pathways, in particularly the ostiomeatal complex. The coronal plane is the best incidence because it most closely correlates with the surgical approach. The utilization of a high resolution bony algorithm is recommended. A window of intermediate type, 2500 with a center of 250 HU, is sufficient for nearly all diagnosis. Complementary direct axial sections are needed by the surgeon to guide the approach to the sphenoid sinus and the posterior ethmoidal cells. MRI plays a limited role in the evaluation of a non complicated sinusitis. But MRI has supplanted the CT scanner in the appreciation of intracranial and orbital complications of sinusitis because it provides better visualisation and differentiation of soft tissues than the CT scan. The injection of contrast is recommended in all cases of complicated sinusitis.

Algorithms↗
PubMed1996

Disorganization of microtubular network in postischemic liver dysfunction: its functional and morphological changes.

Microtubules in the hepatocytes have been implicated to serve as lines of cytoplasmic transport of secretory materials, but are highly labile structures sensitive to pathological conditions in the cytosol. We examined the role of ischemia/reperfusion-induced cytoskeletal alterations in postischemic liver dysfunction. Rabbit livers were subjected to 60-min warm ischemia followed by 1 h or 24 h of reperfusion. Liver function was assessed by directly measuring hepatic clearance of indocyanine green (ICG), an organic anion whose cytoplasmic transport is assumed to depend on intact microtubules, using near-infrared spectroscopy. Structural alterations of microtubules were observed immunohistochemically using tissue sections stained with monoclonal anti-beta-tubulin antibody. ICG removal from hepatocytes into bile canaliculi deteriorated 1 h but reversed 24 h after reperfusion. Immunohistochemistry showed fragmentation of microtubules at the end of liver ischemia. This cytoskeletal alteration was evident 1 h but was not observed 24 h after reperfusion. Treatment with prostaglandin E1 exerted its beneficial effect by preserving ICG clearance and microtubular network. These results demonstrate that liver ischemia and subsequent reperfusion both affect the organization of microtubular network and suggest that structural disruption of microtubules may be a cause of postischemic liver dysfunction.

Actin Cytoskeleton↗
PubMed1996

Vertebral haemangiomas with spinal cord compression: the place of preoperative percutaneous vertebroplasty with methyl methacrylate.

We report on cervical and two thoracic vertebral haemangiomas with neurological disturbance successfully treated by percutaneous vertebroplasty followed by decompression surgery. Vertebroplasty consolidates the vertebral body and reduces the risk of haemorrhage. Subsequent surgery may be limited to decompressive laminectomy and resection of the epidural extension of the haemangioma. embolisation was also carried out in one case. Complete neuroimaging workup, including CT, myelo-CT and MRI, is necessary prior to treatment.

Bone Cements↗
PubMed1996

Localization of synapsin I in normal fibers and regenerating axonal sprouts of the rat sciatic nerve.

The localization of synapsin I, a synaptic vesicle-associated protein, was investigated immunocyto-chemically in normal nerve fibers and regenerating axonal sprouts following crush-injuries to the rat sciatic nerve. In normal myelinated axons, weak synapsin I immunoreactivity was found in the axoplasmic/smooth endoplasmic domains, but not in the cytoskeletal domains comprising neurofilaments and microtubules. In non-myelinated axons without dense cytoskeletal structures, moderate immunoreactivity was distributed diffusely throughout the axoplasm. In the crush-injured nerves, intense synapsin I immunoreactivity was demonstrated by light microscopy in early regenerating sprouts emerging from nodes of Ranvier. These nodal sprouts subsequently elongated as regenerating axons through the space between the basal lamina and the myelin sheath (or Schwann cell plasma membrane). Intense synapsin I immunoreactivity was also found in the growth cones of such long regenerating axons. Electron microscopy revealed that synapsin I immunoreactivity was associated mainly with vesicular organelles in the nodal sprouts and growth cones of regenerating axons. Long regenerating axons exhibited no synapsin I immunoreactivity in the shaft, which contained an abundance of neurofilaments. However, vesicle accumulations remaining in the periphery of the shaft still exhibited intense synapsin I immunoreactivity. Thus, it can be concluded that synapsin I is localized at especially high density in the domains comprising vesicular organelles, which are characteristic of early nodal sprouts, as well as in growth cones of regenerating axons. These findings, together with the proposed functions of synapsin I investigated in other studies, suggest that synapsin I may play important roles in vesicular dynamics including the translocation of vesicles to the plasma membrane in sprouts and growth cones of regenerating axons.

Animals↗
PubMed1996

Alpha N-catenin expression in the normal and regenerating chick sciatic nerve.

The Ca(2+)-dependent intercellular adhesion molecule cadherin is known to be linked to the cytoskeleton by the protein catenin, an association of which appears to be important for the cell-adhesion function of cadherin. Catenin consists of three subtypes-alpha, beta, and gamma. In our previous study, N-cadherin was shown to be localized on the plasmalemma of normal and regenerating chick peripheral nerve. Thus, as alpha N-catenin is a subtype of alpha-catenin (which is specifically associated with N-cadherin), we investigated the immunolocalization of alpha N-catenin in normal and regenerating chick sciatic nerve. In normal nerve, unmyelinated axons exhibited either intense or weak alpha N-catenin immunoreactivity throughout the axoplasm, whereas myelinated axons were completely immunonegative. Regenerating axons, including those derived from parent myelinated axons, showed alpha N-catenin immunoreactivity of variable intensities in growth cones and axon shafts. Schwann cells were invariably devoid of immunoreactivity. Thus alpha N-catenin is not necessarily bound to the surface plasmalemma, but is distributed throughout the cytoplasm, suggesting that most alpha N-catenin molecules are dissociated from N-cadherin.

Animals↗
PubMed1996

Peripheral nerve regeneration.

Peripheral nerve regeneration comprises the formation of axonal sprouts, their outgrowth as regenerating axons and the reinnervation of original targets. This review focuses on the morphological features of axonal sprouts at the node of Ranvier and their subsequent outgrowth guided by Schwann cells or by Schwann cell basal laminae. Adhesion molecules such as N-CAM, L1 and N-cadherin are involved in the axon-to-axon and axon-to-Schwann cell attachment, and it is suggested that integrins such as alpha 1 beta 1 and alpha 6 beta 1 mediate the attachment between axons and Schwann cell basal laminae. The presence of synaptic vesicle-associated proteins such as synaptophysin, synaptotagmin and synapsin I in the growth cones of regenerating axons indicates the possibility that exocytotic fusion of vesicles with the surface axolemma supplies the membranous components for the extension of regenerating axons. Almost all the subtypes of protein kinase C have been localized in growth cones both in vivo and in vitro. Protein kinase C and GAP-43 are implicated to be involved in at least some part of the adhesion of growth cones to the substrate and their growth activity. The significance of tyrosine kinase in growth cones is emphasized. Tyrosine kinase plays an important role in intracellular signal transduction of the growth of regenerating axons mediated by both nerve trophic factors and adhesion molecules. Growth factors such as NGF, BDNF, CNTF and bFGF are also discussed mainly in terms of the influence of Schwann cells on regenerating axons.

Animals↗
PubMed1996

Electromagnetic field induced changes in lipid second messengers.

Initial studies with a human hematopoietic cell line, TF-1, suggest multifarious effects of electromagnetic fields on lipid signal transduction. We have examined the effects of pulsed magnetic fields (2 T, 84 microseconds zero-to-peak haversine, 91 V/m induced electric field) on the cell cycle by flow cytometry. A 31% increase of cells in the G1 phase occurred concurrently with a 35% decrease of cells in S-phase, which suggests that doses of 30 or 40 pulses have an anti-proliferative effect. Changes in the lipid second messengers, diacylglycerol (DAG) and phosphatidic acid (PA) with stimuli of 2 T intensity were also dependent on the number of pulses. DAG production doubled with 30 pulses and tripled with 40 pulses, and PA levels were reduced to one third and one tenth of the original levels. Phospholipase D (PLD) up-regulation was assessed directly by the capacity of PLD to catalyze transphosphatidylation in the presence of alcohol. [3H]Phosphatidylethanol formed rapidly and continued to increase with concomitant decreases in [3H]PA and parallel generation of [3H]DAG. Propranolol, an inhibitor of PA phosphohydrolase, inhibited the formation of DAG in a dose-dependent manner with a marked increase in PA production. Examination of the kinetics of formation of [3H]choline and [3H]phosphocholine at different times after stimulation showed a rapid and consistent increase in [3H]choline, whereas [3H]phosphocholine increase was evident only 60 min after stimulation. Magnetic exposure also caused a shift in some molecular species patterns of DAG and PA which could be correlated with phosphatidylinositol, phosphatidylethanolamine and phosphatidylcholine molecular species decreases. Therefore, we propose that the PC-PLC pathway may be temporarily inactivated for a short period of time by exposure to pulsed stimuli, and the PC-PLD pathway is up-regulated based on: (1) cellular release of [3H]choline; (2) rapid intracellular formation of [3H]PA followed by [3H]DAG; (3)active transphosphatidylation; and (4) blockade of DAG formation by propranolol.

Cell Line↗
PubMed1996

Growth cone collapse and inhibition of neurite growth by Botulinum neurotoxin C1: a t-SNARE is involved in axonal growth.

The growth cone is responsible for axonal growth, where membrane expansion is most likely to occur. Several recent reports have suggested that presynaptic proteins are involved in this process; however, the molecular mechanism details are unclear. We suggest that by cleaving a presynaptic protein syntaxin, which is essential in targeting synaptic vesicles as a target SNAP receptor (t-SNARE), neurotoxin C1 of Clostridium botulinum causes growth cone collapse and inhibits axonal growth. Video-enhanced microscopic studies showed (a) that neurotoxin C1 selectively blocked the activity of the central domain (the vesicle-rich region) at the initial stage, but not the lamellipodia in the growth cone; and (b) that large vacuole formation occurred probably through the fusion of smaller vesicles from the central domain to the most distal segments of the neurite. The total surface area of the accumulated vacuoles could explain the membrane expansion of normal neurite growth. The gradual disappearance of the surface labeling by FITC-WGA on the normal growth cone, suggesting membrane addition, was inhibited by neurotoxin C1. The experiments using the peptides derived from syntaxin, essential for interaction with VAMP or alpha-SNAP, supported the results using neurotoxin C1. Our results demonstrate that syntaxin is involved in axonal growth and indicate that syntaxin may participate directly in the membrane expansion that occurs in the central domain of the growth cone, probably through association with VAMP and SNAPs, in a SNARE-like way.

Animals↗
PubMed1996

Percutaneous laser disk decompression under CT and fluoroscopic guidance: indications, technique, and clinical experience.

The aim of percutaneous laser disk decompression (PLDD) is to vaporize a small portion of the nucleus pulposus of an intervertebral disk, thereby reducing the volume and pressure of a diseased disk. This minimally invasive technique can be performed in patients who need surgical intervention for disk herniation with leg pain. PLDD is usually performed under fluoroscopic guidance with or without diskoscopy. However, it can also be performed under dual computed tomographic (CT) and fluoroscopic guidance as an outpatient procedure. CT and fluoroscopic guidance increases the safety and accuracy of PLDD, with high precision of instrument guidance, direct visualization of nucleus pulposus vaporization, and reduced risk of complications. Of 119 patients with lumbar disk herniation treated with PLDD under CT and fluoroscopic guidance, 91 (76.5%) had a good or fair response. PLDD performed with CT and fluoroscopic guidance appears to be a safe and effective treatment for herniated intervertebral disks.

Adolescent↗