Troponin and dystrophin in regenerating muscle fibers with and without denervation.
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Animals↗
Biomedical subjects
M Komiyama
Publications and source records attributed to M Komiyama.
Effects of pectenotoxin-1 on liver cells in vitro.
The effects of pectenotoxin-1 (PTX1), a nondiarrheagenic toxin from mussels, on liver cells were investigated by fluorescence microscopy. The in vitro application of PTX1 to these cells induced reduction in number and loss in radial arrangement of microtubules. It also induced disruption of stress fibers and accumulation of actin at the cellular peripheries. Further studies are worthwhile to explore the feasibility of using PTX1 as a tool for analyzing the properties of cytoskeletal proteins.
Animals↗
Chronic subdural hematoma associated with middle meningeal arteriovenous fistula treated by a combination of embolization and burr hole drainage.
A rare case of chronic subdural hematoma associated with a middle meningeal arteriovenous fistula was treated by a combination of embolization and burr hole drainage. This clinical situation might be missed in this era of computed tomography, when cerebral angiography is seldom indicated for the diagnosis of neuro-traumatic diseases. We should bear in mind the possibility of this clinical situation of a chronic subdural hematoma associated with a linear skull fracture crossing the middle meningeal groove in order to avoid possible hemorrhagic complications during surgery for chronic subdural hematoma.
Arteriovenous Fistula↗
Catalytically active species for CeCl3-induced DNA hydrolysis.
Cerium(III) chloride efficiently hydrolyzes DNA at pH 7 under aerobic conditions. A titration study showed that Ce(III) is oxidized to Ce(IV) in the reaction mixture and the resultant Ce(IV) is responsible for the DNA hydrolysis.
Catalysis↗
Lanthanide ions for the first non-enzymatic formation of adenosine 3',5'-cyclic monophosphate from adenosine triphosphate under physiological conditions.
Adenosine 3',5'-cyclic monophosphate (cAMP) is formed from adenosine triphosphate at pH 8 and 50 degrees C by use of lanthanide ions. Pr3+ and La3+ are the most active. The cAMP formation is more efficient at higher pH, where the mixture is made homogeneous by the addition of beta-cyclodextrin. The potential functioning of lanthanide ions as the catalytic center of an artificial adenylate cyclase is indicated.
Adenosine Triphosphate↗
Selective hydrolysis of tRNA by ethylenediamine bound to a DNA oligomer.
A sequence-selective artificial ribonuclease was prepared by attaching ethylenediamine to the 5'-end of a DNA oligomer as the sequence-recognizing moiety. The hybrid, incorporating a 19-mer DNA which is complementary with the A44-A62 sequence of tRNA(Phe), hydrolyzed the tRNA selectively at the 3'-side of C63.
Base Sequence↗
Endovascular treatment of acute thrombotic occlusion of the cervical internal carotid artery associated with embolic occlusion of the middle cerebral artery: case report.
A 68-year-old man with acute, total thrombotic occlusion of the right cervical internal carotid artery, associated with embolic occlusion of the ipsilateral middle cerebral artery, was treated by the endovascular approach, i.e., intra-arterial fibrinolysis and balloon angioplasty. Endovascular treatment for a totally occluded internal carotid artery is indicated in the very early stage where there is no thrombus or a short thrombus that can be evacuated. Fibrinolysis of the associated embolus in the middle cerebral artery, if any, can be done in the same session, enabling an early restoration of the blood flow.
Aged↗
"Kissing aneurysms" of the internal carotid artery.
Five patients with kissing aneurysms (adherent internal carotid-posterior communicating artery and ipsilateral internal carotid-anterior choroidal artery aneurysms) are reported. There was female predominance and the subarachnoid hemorrhage was commonly due to rupture of the proximal posterior communicating artery aneurysm. Despite the demonstration of angiographic cleavage, the two aneurysms adhere to each other, which makes surgical dissection difficult. Meticulous dissection of the aneurysmal necks and preservation of the blood flow in the anterior choroidal artery are of vital importance.
Adult↗
Effects of cyclochlorotine on myofibrils in cardiomyocytes and on actin filament bundles in fibroblasts in vitro.
The effects of cyclochlorotine (CC), a secondary metabolite of Penicillium islandicum, on cardiomyocytes and fibroblasts were investigated by fluorescent and electron microscopy. The in vitro application of CC on myocytes induced disruption of myofibrils and large accumulations of actin, myosin, alpha-actinin, and vinculin at the cellular processes. This agent also induced the formation of islands of myosin and alpha-actinin aggregates. Actin filament bundles in fibroblasts were either unaffected or disrupted completely, suggesting the presence of two, physiocochemically different, populations of fibroblasts. CC damage was dose-dependently reversible. Further studies will be required to explore the feasibility of using CC for analyzing the properties of contractile and/or cytoskeletal proteins.
Actins↗
[Rebleeding of ruptured intracranial aneurysms in the acute stage].
Among the cases of ruptured aneurysms we have handled, some patients have rebled before surgery was performed. In this study, we examine the factors that contribute to the rerupture of cerebral aneurysms in the acute stage and suggest measures to prevent rerupture prior to surgery. We have encountered 32 cases of rebleeding prior to surgery. The rebleeding occurred within six hours of the initial subarachnoid hemorrhage (SAH) in 26 patients, among whom 21 rebled within three hours. Thirteen patients rebled during bed rest, 10 patients during angiography, 4 patients during CT scan and 5 patients in various other circumstances. Nine of the 10 patients who rebled during angiography had undergone the procedure within three hours of the initial SAH. Overall, the patients' condition deteriorated substantially after rebleeding. Considering these circumstances surrounding aneurysmal rerupture, we suggest the following measures for the prevention of preoperative rerupture in the acute stage: 1) maintenance of lowered blood pressure during the risky period; 2) intentional delay of performance of angiography until at least hours after the initial rupture, and 3) performance of surgery on an emergency basis.
Acute Disease↗
[Surgical treatment of arteriovenous malformations in the brain stem].
The authors report the surgical removal of four arteriovenous malformations (AVM's) in the brain stem causing hemorrhage. These included two intra-axial and two extra-axial AVM's. Three of the four were situated at the pons, and the remaining one in the posterior medullary velum. Complete surgical removal was obtained in the two extra-axial cases and in one of the intra-axial cases. The patient in whom complete removal was not obtained received partial embolization therapy with the remaining feeder being coagulated surgically. No patient was made permanently worse after surgery. One patient, in a comatose state on admission, died, while the remaining three patients showed useful recovery. These data indicate that surgical therapy with or without endovascular surgery appears to be possible for some AVM's and can be performed at an acceptable risk.
Adult↗
Enhancement of the cleavage rates of DNA-armed hammerhead ribozymes by various divalent metal ions.
In order to characterize structure-function relationships, the kinetic behavior of chimeric RNA/DNA ribozyme was compared with that of all RNA ribozyme. Determined kcat values were proven to represent the chemical-cleavage step and not the product-dissociation step. In agreement with the finding by Dahm and Uhlenbeck [Biochemistry 30, 9464-9469 (1991)], various metal ions, including Co2+ and Ca2+ with the ionic radius of 0.65 and 1.0 A, respectively, could support hammerhead cleavage for both types of ribozyme. Measurements of kinetic parameters in the presence of various divalent metal ions revealed that DNA arms always enhanced kcat values. Chemical-probing data using dimethylsulfate indicated that the catalytic-loop structures of all-RNA and chimeric ribozymes were nearly identical with the exception of enhanced termination of primer extension reactions at C3 in the case of the chimeric ribozyme. These observations and others demonstrate that DNA substitution in non-catalytic-loop regions increases chemical-cleavage activity, possibly with an accompanying very subtle change in the structure.
Base Sequence↗
Dynamics of actin and assembly of connectin (titin) during myofibrillogenesis in embryonic chick cardiac muscle cells in vitro.
Immunogold electron microscopy of cardiac myocytes microinjected with biotin-labeled actin showed that gold labeling was first found around the A band level of myofibrils at their proximal parts. This observation suggests that polymerization of actin and/or the addition of newly formed actin filaments occurs preferentially in association with myosin filaments to increase the myofibrillar girth. At the distal portions of developing myofibrils, their terminal ends were initially labeled, suggesting that continued reorganization and/or de novo formation of myofibrils occurs at these locations. Soon, gold particles were seen along the termini of growing myofibrils. This appears to indicate that actin subunits are added at the membrane-associated ends of preexisting actin filaments to increase the length of myofibrils. Adhesion plaque proteins, e.g., vinculin, do not appear to play any role in assembling actin monomers at these sites on the inner surface of the sarcolemma. Immunofluorescence and immunoelectron microscopy of cardiomyocytes double-stained with antibodies against two distant domains of connectin (titin) filaments and other sarcomeric proteins showed that these domains of connectin filaments and myosin were synthesized almost simultaneously on large polyribosomes and/or associated immediately after the synthesis of these molecules. Connectin and myosin bands were formed after alpha-actinin striations (Z bands) were seen on preformed I-Z-I-like structures.(ABSTRACT TRUNCATED AT 250 WORDS)
Actinin↗
Extravasation of contrast medium from the lenticulostriate artery following local intracarotid fibrinolysis.
Two patients with acute embolic occlusion of the intracranial internal carotid artery and the lenticulostriate arteries were treated by local intraarterial fibrinolysis using tissue plasminogen activator. Although fibrinolysis started within 2.5 hours from the ictus, extravasation of the contrast medium from the lenticulostriate arteries occurred in the region of the basal ganglia. Local intraarterial fibrinolysis for acute embolic occlusion of the internal carotid artery may be a high-risk therapeutic intervention even within the ultra-acute stage, especially when the lenticulostriate arteries are occluded by an embolus.
Aged↗
Mechanism of acute deterioration of the neurological status following rapid and massive intraluminal thrombosis in case of a giant intracavernous carotid artery aneurysm: demonstration by MR imaging.
A case is reported of a thrombosed giant aneurysm of the intracavernous carotid artery. Transient neurological deterioration was attributable to the acute swelling of the aneurysmal mass after rapid and massive intraluminal thrombosis. Characteristics on the magnetic resonance imaging of this case are reported and discussed.
Acute Disease↗
Dural arteriovenous fistula: a cause of hypoperfusion-induced intellectual impairment.
A 76-year-old, right-handed man developed posttraumatic dural arteriovenous fistula (DAVF) involving the superior sagittal sinus. He developed slow but progressive intellectual deterioration and gait disturbance after a minimal head trauma. Cerebral angiography demonstrated a DAVF of the superior sagittal sinus with sinus thrombosis supplied by branches of the bilateral external carotid arteries, and a DAVF of the right sigmoid sinus supplied by the right occipital artery. Selective embolization was carried out. He showed marked improvement on neuropsychological testing, especially on test items which are supposed to tap functions of the right cerebral hemisphere which showed an improved cerebral blood flow. We concluded that the intellectual impairment of our patient was caused by cerebral hypoperfusion, especially of the right cerebral hemisphere.
Aged↗
Aneurysmal rupture during angiography.
The aim of the present study was to analyze the clinical data on rebleeding in cerebral aneurysms during angiography and to evaluate the importance of the time interval between the latest rupture and angiography. Fourteen personal cases and 202 patients reported in the literature are reviewed. Rebleeding during angiography occurred most often (78%) on Day O; 89% bled when angiography was performed within 6 hours of the latest rupture. The prognosis in such ruptures was poor, with a mortality of 79%. Intentional delay in angiography of at least 6 hours from the latest rupture is recommended if the associated hematoma is not large.
Adult↗
Pontine hemorrhages presenting as trigeminal neuropathy--report of three cases.
Three patients with pontine hemorrhages presenting clinically as trigeminal neuropathy are described. No patient was hypertensive and angiograms were normal. Magnetic resonance (MR) imaging showed heterogeneous lesions, suggesting cavernous malformation, in one patient, but no definite diagnosis could be made in the other two patients. Such cases are rare and should be evaluated using serial MR imaging to differentiate angiographically occult vascular malformation from spontaneous hemorrhage.
Adult↗