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Biomedical subjects

A Matsuno

Publications and source records attributed to A Matsuno.

89 records · Page 5Linked to original sources
PubMed1992

Characterization and localization of alpha-connectin (titin 1): an elastic protein isolated from rabbit skeletal muscle.

A simplified procedure to isolate alpha-connectin (titin 1, TI), a gigantic elastic protein, from rabbit skeletal muscle is described. A rapid column chromatography step to concentrate alpha-connectin is introduced. Separation of alpha-connectin from beta-connectin is introduced. Separation of alpha-connectin from beta-connectin (titin 2, TII) in the presence of 4 M urea at pH 7.0 did not cause any change in the secondary structure of alpha-connectin as judged by circular dichroic spectra. Ultraviolet absorption spectra and the amino acid composition of alpha-connectin (MW, approximately 3 x 10(6)) were similar to those of its proteolytic product, beta-connectin (MW, approximately 2 x 10(6)). Circular dichroic spectra suggested that both alpha- and beta-connectin consist of 60% beta-sheet and 30% beta-turn. It thus appears that the whole elastic filament of connectin has a folded beta-strand structure. Proteolysis of alpha-connectin by calpain resulted in formation of beta-connectin and smaller peptides. The alpha-connectin interacted with both myosin and actin filaments similarly to beta-connectin. Polyclonal antibodies raised against 1200 kDa peptides obtained from aged rabbit skeletal myofibrils reacted with alpha-connectin (titin 1, TI) but only weakly with beta-connectin (titin 2, TII) in rabbit skeletal muscle. Immunoelectron microscopy and indirect immunofluorescence microscopy revealed that the antibodies bound at the Z-line and at the epitope regions in the I-band near the binding site of a monoclonal antibody SM1 whose position depends on sarcomere length. It thus appears that beta-connectin extends from the edge of M-line to the above epitope region in the I-band.

Actins↗
PubMed1992

[A case of primary intracranial malignant melanoma showing leptomeningeal dissemination].

A 28-year-old woman was hospitalized in drowsy state with signs of increased intracranial pressure. CT scans revealed diffuse increased density with marked enhancement in the subarachnoid space, as well as ventricular dilatation. V-P shunt operation was performed to control intracranial pressure. Repeated cytological examinations of CSF couldn't determine the tumor origin. CT scan of thoracic spine showed a cystic tumor in its dorsal aspect. T2-weighted MRI revealed multiple spotty low intensity, specific to melanin granules, throughout the whole spine. Her thoracic spine was explored, and the intradural tumor was partially removed. Histopathological examination revealed the tumor cell which had dark nucleus with conspicuous nucleolus and cytoplasmic granules. These findings were compatible with malignant melanoma. Her general condition were deteriorated progressively and she died about 5 months after her admission. Postmortum examination showed diffuse leptomeningeal invasion of dark tumor throughout the entire central nervous system, and metastasis to peritoneum and omentum via V-P shunt system. Histopathological examination proved the tumor to be malignant melanoma. Electrone microscopic examination also revealed melanosome in the cytoplasm. Primary intracranial malignant melanoma is divided in two groups, nodular type and leptomeningeal type. In the latter type, early diagnosis is very difficult, just as in our case, because only a little tissue specimen can be obtained. In a case of leptomenigeal carcinomatosis, possibility of primary malignant melanoma, though rare, should always be kept in mind, and specific staining such as Fontana-Masson's staining should be tried.

Adult↗
PubMed1992

[Sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment; a case report].

A case of sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment is reported. A 73-year-old woman visited our hospital with the complaint of head heaviness on the 27th of March, 1989. Although results of neurological examinations were normal, craniogram revealed the destruction of the clivus, and CT scan and MRI showed a mass lesion, which was thought to be a mucocele in the sphenoid sinus. On the 1st of September, she developed right abducens nerve palsy and visual field impairment. MRI performed on the same day showed an enlargement of the mass lesion in the sphenoid sinus. In order to decompress the involved cranial nerves, her sphenoid sinus was explored on the 22nd of September. The sphenoid sinus was filled with purulent fluid and yellowish mass. Histopathological examination revealed colonies of aspergillus fumigatus. Fluconazole, a new antifungal drug, was given for 34 days postoperatively. The right abducens nerve palsy and the visual field impairment gradually improved along with a reduction of the mass lesion in her sphenoid sinus. Sphenoid sinus aspergillosis is a rare disease. Its diagnosis is difficult. However, MRI can show a specific low signal intensity in T2-weighted image. Also in our case, MRI on the first admission showed a definite low signal intensity in some parts of the lesion, which exhibited a high intensity later on during the second administration, probably due to a qualitative change. To our knowledge, only 33 such cases have been previously reported. Intracranial involvement occasionally occurs in this disease. In its early stage, cranial nerve palsies are caused by nerve compression or invasion by this disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Abducens Nerve↗
PubMed1992

[Quantitative analysis of eye movement during VDT work].

The point of fixation during visual display terminal (VDT) work was analyzed by using Eye Mark Recorder-NAC with their corneal reflexes. The subjects were categorized into 2 groups, expert VDT worker and non-expert with VDT work. As for the VDT task, Japanese sentences were loaded. On the other hand, ordinary desk work copying was loaded using the same Japanese sentences. The following results were obtained. VDT work needed more complex eye movements in both vertical and horizontal directions compared with desk work. The point of fixation was mainly located on the surface of the oscilloscope in the expert subjects, whereas, it was mainly located on the keyboard in non-expert subjects. In analyzing the velocity of eye movements during VDT work, the expert moved the eyes more slowly than the non-expert. These results suggested that the VDT experts can move their eyes more effectively and slowly.

Adult↗
PubMed1992

[Unexpected air embolism during an aneurysmal operation in supine position--a case report and a speculation about its pathogenesis].

The occurrence of air embolism in supine position operation is extremely rare. We reported a case of air embolism during the operation of a ruptured middle cerebral artery aneurysm in supine position. A 58-year-old woman was admitted to our hospital in semicomatous state. A CT scan revealed diffuse subarachnoid hemorrhage. Cerebral angiogram showed a middle cerebral artery aneurysm. Massive pinkish foamy sputum and butterfly shadow on chest x-ray strongly suggested an association of neurogenic pulmonary edema (NPE). Barbiturate therapy and controlled ventilation with positive end-expiratory pressure (5cmH2O) were started. Her airway pressure was about 35cmH2O. Decrease of pinkish foamy sputum and an improvement of chest x-ray findings on the next day encouraged us to perform a clipping operation. Just before a clip application, air bubbles were observed to pass through the middle cerebral artery under the microscope. Subsequently cardiac standstill was brought out. Fortunately, she was resuscitated, and a clip application was finished. A postoperative CT scan revealed an infarction in the middle cerebral artery area. A postoperative cerebral angiogram showed occlusion of a temporal branch of the right middle cerebral artery, P1 portion of the left posterior cerebral artery, and the right superior cerebellar artery. We speculated that high endotracheal pressure brought out pulmonary alveolar rupture, and in spite of supine position operation massive air, which flowed into systemic circulation from ruptured alveoli, caused cerebral infarction and cardiac arrest. We consider that unrecognized air embolism might be the one of the factors influencing the prognosis of severe subarachnoid hemorrhage, especially in the cases associated with neurogenic pulmonary edema.

Embolism, Air↗
PubMed1990

[Development of all-silicone detachable balloons].

Treatment of cerebral vascular lesions such as carotid cavernous sinus fistulas and giant aneurysms is now being performed with intravascular detachable balloon embolization techniques. We have developed several types of all-silicone detachable balloons. Our balloons have self-sealing valves (with or without collars) and detach with simple traction. The self-sealing valve is smaller than 0.6 mm and the balloon can easily be placed through a 7-F catheter. We started clinical trials and a representative case was reported.

Embolization, Therapeutic↗
PubMed1990

Projectin is an invertebrate connectin (titin): isolation from crayfish claw muscle and localization in crayfish claw muscle and insect flight muscle.

A filamentous protein was isolated from crayfish claw muscle. This protein had physiochemical properties very similar to vertebrate skeletal muscle connectin (titin), although its apparent molecular mass (approximately 1200 kDa) was considerably lower than that of connectin (approximately 3000 kDa). Polyclonal as well as monoclonal antibodies against chicken skeletal muscle connectin reacted with the 1200 kDa protein from crayfish claw muscle. Conversely, polyclonal antibodies against crayfish 1200 kDa protein cross-reacted with chicken connectin. Circular dichroic spectra indicated the abundance of beta-sheet structure (approximately 60%). Low-angle shadowed images showed filamentous structures (0.2-0.5 microns) by electron microscopy. Proteolysis of the 1200 kDa protein by alpha-chymotrypsin or V8 protease rapidly resulted in formation of 1000 kDa or 1100 and 800 kDa peptides. The amino acid composition was very similar to those of vertebrate connectins and of honeybee flight muscle projectin. Based on the molecular weight and amino acid composition, the 1200 kDa protein is regarded to be crayfish projectin. Immunofluorescence and immunoelectron microscopy revealed that crayfish projectin was localized in the A/I junction area and A-band except for its centre region in crayfish claw muscles. Polyclonal antibodies against crayfish claw muscle projectin reacted with 1200 kDa projectin of honeybee and beetle flight muscle. A monoclonal antibody against chicken skeletal muscle connectin also reacted with honeybee and beetle projectin. Immunoelectron microscopic observations revealed that anti-crayfish projectin antibodies bound the connecting filaments linking the Z-line and the thick filaments up to the M-line of honeybee muscle sarcomere. Anti-crayfish projectin antibodies bound the I-band region near the Z-line of beetle flight muscle. It is concluded that the 1200 kDa projectin from crayfish claw muscle is an invertebrate connectin (titin). Recent work with locust flight muscle mini-titin (Nave & Weber, 1990) is in good agreement with the present study, except that the isolated mini-titin estimated as 600 kDa appears to be a proteolytic product (approximately 1100 kDa) of the parent molecule (approximately 1200 kDa).

Actin Cytoskeleton↗
PubMed1989

Behaviour of connectin (titin) and nebulin in skinned muscle fibres released after extreme stretch as revealed by immunoelectron microscopy.

Stretching of skinned fibres of frog skeletal muscle beyond the overlap of the thin and thick filaments followed by release to resting length results in disorganization of the thin filaments at the A-I junction of a sarcomere (Higuchi et al. (1988) J. Muscl. Res. Cell. Motility 9, 491-8). Immunoelectron microscopic observations showed that the binding sites of antibodies against connectin (titin) returned to the original position after extreme stretch and release but those of anti-nebulin antibodies were largely disorganized. The binding sites of anti-connectin antibodies moved within an I band with the change in sarcomere length, but those of anti-nebulin antibodies did not. Nebulin remained in the I band at extreme stretch. Thus connectin filaments appear to be responsible for maintaining mechanical continuity of a sarcomere and appear to behave independently of thin filaments. It is suggested that nebulin is localized in the I band but not in the A band and is associated with thin filaments but not with the elastic structure of myofibrils.

Animals↗
PubMed1988

Ultrastructural differences between the anterior and posterior adductors of the strawberry cockle, Fragum unedo.

Adductors of Fragum unedo were observed ultrastructurally and their muscle cells were classified according to the statistically analyzed diameter of their thick myofilaments. Two types of smooth muscle cells were observed in the opaque portion of the anterior adductor: A-type cells containing thick myofilaments of about 46 nm in diameter and B-type cells having 62 nm thick myofilaments. The posterior adductor was also composed of two kinds of cells: the B-type cell, which had thick myofilaments of about 67 nm in diameter, and the C-type, containing thick myofilaments of 90 nm. Two types of oblique-striated cells were commonly recognized in the translucent portions of anterior and posterior adductors. Our observations thus indicate that the posterior adductor generally consists of cells which have thicker myofilaments than the ones of the anterior adductor.

Animals↗
PubMed1988

Ultrastructural investigations on the anterior adductor muscle of a brachiopoda, Lingula unguis.

The brachiopoda, Lingula unguis, has a pair of anterior adductors located in the center of the shell. Each muscle consists of an opaque and a translucent portion which is constructed of smooth and obliquely-striated muscle respectively. According to our ultrastructural observations, the opaque portion seems to have two types of cells. They differ only in the diameters of their thick myofilaments. The fine structure of their cell organelles resembles each other. We measured the diameters of the thick myofilaments in each type of cell to distinguish between the two cell types. About 500 measurements of myofilament diameters were made for each type of cell and statistically analyzed. For one type of cell, the distribution of diameters of the thick myofilaments fit a normal distribution curve with a peak at 37-60 nm. The distribution of diameters of the thick myofilaments for the other type fit a curve in which two normal distribution curves having peaks at 37-60 and 75-97 nm respectively partially overlapped. According to these results, we suggest that the opaque portion contains two types of cells, each having a different distribution of thick myofilament sizes.

Animals↗
PubMed1988

Primary leiomyosarcoma of the dura mater. Case report.

A rare case of leiomyosarcoma arising from the dura mater is presented. A definite histological diagnosis was based on the electron microscopic features. Extensive removal of the tumor and postoperative radiation therapy resulted in complete remission. The etiology and the origin of this tumor are discussed.

Aged↗
PubMed1987

Morphology, growth and reversion in a stable L-form of Escherichia coli K12.

An L-form isolated from Escherichia coli K12 by sequential treatment with N-methyl-N'-nitro-N-nitrosoguanidine and lysozyme was adapted to grow in hyperosmolar liquid cultures. It was stable in the absence of antibiotic when cultured in brain heart infusion (BHI) broth containing NaCl and CaCl2, the optimal concentrations being 0.34 M and 1 mM, respectively. No growth of the L-form was observed when CaCl2 was not added to BHI medium containing 0.34 M-NaCl. On the other hand, when KCl replaced NaCl as the osmotic stabilizer, growth of the L-form was repressed in the presence of CaCl2. Electron microscopy of the L-form confirmed the absence of a cell wall. A revertant strain derived from the L-form grew as a stable bacillary form in BHI medium without osmotic stabilizer. The growth characteristics of the revertant strain resembled those of the parent strain. The revertant strain produced L-forms in the presence of NaCl.

Culture Media↗
PubMed1987

[Primary intracranial epidermoid carcinoma accompanied with epidermoid cyst in the cerebellopontine angle--a case report].

A case of epidermoid carcinoma arising in an epidermoid cyst in the cerebellopontine angle is presented. Clinical features and CT appearance are discussed in comparison with those of benign epidermoid cyst. A 43-year-old man was admitted to the Department of Neurosurgery, University of Tokyo Hospital on April 14, 1983, with complaints of right facial numbness and weakness of six months' history. On neurological examination, sensation of the right half of the face was decreased in all modalities. Marked atrophy of the ipsilateral temporal muscle was also noted. Right facial paresis of peripheral type was evident. Gag reflex was decreased on the same side. Except for a slightly increased left deep tendon reflexes, there were no pyramidal tract signs. A CT without contrast material failed to show any abnormalities. A postcontrast CT demonstrated an irregular enhancement in the right cerebellopontine angle. The finding of asymmetry of the ambient cistern indicated minimum mass effect on the metrizamide CT cisternography. Suboccipital exploration of the right cerebellopontine angle was carried out on April 28, 1983. Leaving a part of the capsule indenting the pons between the roots of the fifth and the seventh nerve, we removed a white pearly tumor. Histological diagnosis was typical epidermoid cyst. He left the hospital one month later with signs of the right seventh and the eighth nerve. His postoperative course, however, was beyond our expectation. Over a few months following his discharge, left hemiparesis as well as horizontal and vertical nystagmus gradually developed. He was readmitted on November 10, 1983. A postcontrast CT revealed enlargement of the enhanced lesion filling the right ambient cistern.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Ultrastructural observations of motile iridophores from the freshwater goby, Odontobutis obscura.

The ultrastructure of "motile" iridophores of Odontobutis obscura and the changes in cell shape related to the motility were studied with electron microscopy. Various structural details were revealed by this method, and their importance is discussed. Of particular interest were the abundant microfilaments observed in the cortical cytoplasm. Cross-sectional profiles of iridophores showed that, in an iridophore in the dendritic state, the platelets were scattered randomly throughout the centrosphere and its processes, so that the centrosphere appeared to be rather flat. In the punctate state, the platelets were gathered, in groups or in stacks with regular arrangements, in the centrosphere, which appeared to be ovoid in shape. The most notable finding was that, at this time, the processes from which the platelets were lost remained there without retracting. The results indicates clearly that the motility of the goby iridophores involves the migration of platelets within the fixed contour of each cell and that no amoeboidal changes in the shapes of the cells occur.

Animals↗