Biomedical subjects
Publications and source records attributed to M Sameshima.
peanut agglutinin, a lectin with specific affinity for galactose beta-(1----3)-N-acetyl-galactosamine disaccharides, showed binding to the slender cones in the rod-free fovea as well as to the conical cones in the periphery of the monkey (Macaca fuscata) retina, but not to the rods, as revealed by light-microscopic cytochemistry with horseradish-peroxidase-conjugated lectin.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Uncommon complications of hypermature cataract in two aged patients are described. One patients, a 58-year-old woman, with unilateral hypermature cataract secondary to Fuchs' heterochromic cyclitis developed spontaneous absorption of the lens material, followed by its dislocation into the anterior chamber. The other patient, a 63-year-old woman, showed phacolytic glaucoma associated with extensive retinal perivasculitis which concurred with leakage of hypermature cataractous lens material and subsided with its complete absorption. Histopathology of the membraneous cataract revealed degenerative changes of the capsule and extinction of the epithelial cells and cortical fibers.
The silent period and a rhythmic slower wave in EMG appear preceding a rapid voluntary movement (Tanii 1984). The present study was performed to investigate temporal relationships of the EMG changes preceding movement to premovement cortical potential shifts, in order to clarify whether the EMG changes are related to preparation and initiation of voluntary movement. A strong push of a hard band with the right wrist was conducted rapidly following a slightly sustained contraction. The surface EMG was detected from the right triceps brachii muscle. The EEG was recorded from C3, Cz and C4. Slowing of the EMG occurred before the movement in addition to the slower wave. The EMG slower waves were accompanied by a negative deflection of raw EEG potentials. The averaged cortical potentials preceding movement fell into 3 negative potentials. The first potential started about 1.0 sec before the EMG burst. Many of the EMG slower waves occurred in the phase of the second potential occurring 330-510 msec before the EMG burst. Premovement silent period appeared in the phase of the third potential occurring 30-60 msec before the EMG burst. Amplitude of these potentials was larger in the contralateral hemisphere than in the ipsilateral one. This asymmetry became statistically significant in the phase of the second potential. The results suggest that the EMG slower waves and the premovement silent period are associated with preparation and initiation of voluntary movement.
When bacteriophage lambda DNA was injected into the cytoplasm of the fertilized egg of Xenopus laevis, giant nucleus-like structures were assembled around the injected DNA. These nucleus-like structures survived during cleavage and were partitioned into blastomeres at the blastula stage. The nucleus-like structures formed in the uncleaved fertilized eggs and the blastula cells were both surrounded by a bilayer nuclear membrane with nuclear pore complexes. The ultrastructural features of the lambda DNA-induced nucleus-like structure were considerably different from those of the normal blastula nucleus: although the nuclear pore complexes appeared to be normal, the 'nucleoplasm' was much too homogeneous as compared with that of the normal nucleus.
The binding sites of two lectins, peanut agglutinin (PNA) and wheat germ agglutinin (WGA), in the interphotoreceptor matrix (IPM) and photoreceptor plasma membranes of the Japanese monkey (Macaca fuscata) retina were localized using a pre-embedding staining method with ferritin-conjugated (Fer) lectins as well as a postembedding staining method with fluorescence-labeled (FITC) lectins. FITC-PNA, but not WGA, stained cylindrical domains of the IPM around cone outer and inner segments, while the IPM around rods stained with FITC-WGA but not PNA. When the intact (not detached) retinal tissues were incubated with Fer-lectin, the lectin generally labeled neither the IPM nor photoreceptor plasma membranes, but labeled only those structures in detached portions occurring at the edges of occasional retinal tissue blocks. Thus, the neural retinas physically isolated from the retinal pigment epithelium (RPE) were utilized principally here. Ultrastructurally, the IPM in the intact retina consisted of granular and filamentous materials; the IPM in the isolated neutral retina also retained those components, although somewhat loosely organized, and the IPM around cones appeared to be preserved better than did the IPM around rods. Fer-PNA bound to the IPM associated with cones, but not rods; Fer-WGA bound to the rod- but not cone-associated IPM. The ferritin particles were found to lie close to the granular and filamentous materials. Those photoreceptor-associated IPMs extended to the apical surface of the RPE in detached portions or to the apical villi of the RPE which were frequently found in the isolated neural retinas. Also, Fer-PNA labeled the cone, but not rod, plasma membranes; Fer-WGA bound heavily to the plasma membranes of rod and cone outer segments, but sparsely to those of their inner segments. These results suggest that the IPM comprises chemically and physically differential domains specialized for cone and rod photoreceptor cells, and that these specialized IPM are structurally so stable that may be involved in isolating photoreceptor cells physicochemically from each other and in the interactions between the photoreceptors and the RPE, such as retinal adhesion.
Two patients with Leber's hereditary optic neuropathy underwent morphological and biochemical investigations of muscle biopsy samples from the biceps brachii. Although clinically there was no muscle weakness or atrophy, specific histochemical and electron microscopic examinations showed mild but distinct myopathic changes, including abnormal oxidative enzyme activities, aggregates of enlarged mitochondria in the subsarcolemmal regions, and disruptions of myofilaments. Biochemical analyses of mitochondria isolated from muscle samples did not show and deficiency in respiratory-chain enzyme complexes or defect in content of cytochromes. Leber's hereditary optic neuropathy is assumed to be a multisystem disorder involving skeletal muscle also.
The purpose of this study was to examine motor control and kinesthetic perception of upper extremity in patients with Duchenne progressive muscular dystrophy. Nine normal subjects and nine subjects with muscular dystrophy performed a pursuit tracking task with step wave target by means of isometric contraction, and simultaneously estimated magnitude of muscular tension during tracking behavior. The results were as follows: (1) the muscular electrical activity measured from the EMGs was directly proportional to the muscular tension for both the normal and the muscular dystrophy groups, (2) the speed of step response for the muscular dystrophy group was slower than that for the normal group, and (3) the exponent of power function for the muscular dystrophy group tended to be smaller than that for the normal group. These results were discussed in terms of the stage of disability in progressive muscular dystrophy.
Explore the source record for details and available documents.
When a drug is instilled into the bladder provided with experimental cystitis, the drug could be transferred into the serum. We studied the transfer of mecillinam into the serum, and found that the extent of transfer varied with the method to cause experimental cystitis and also occurred even in the normal bladder. It was suspected that in the inflamed bladder, a part of mecillinam excreted into the urine would possibly be transferred again into the serum through bladder wall.
The fate of bacteriophage lambda-DNA was examined after injection into the fertilized eggs of Xenopus laevis. Injection of a large amount of lambda-DNA (ca. 24 ng) into a fertilized Xenopus egg induced the formation around the injected DNA of a giant nucleus-like structure which was surrounded by an apparently normal bilayered nuclear membrane with nuclear pore complexes. Southern blot analysis revealed the persistence of injected lambda-DNA until the blastula stage. The nucleus-like structure was partitioned into blastomeres during cleavage through a process of nuclear fission, and was maintained in a group of extraordinarily large blastomeres until the blastula stage.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
From rabbit antiserum against peanut agglutinin (PNA)-receptors of the bovine interphotoreceptor matrix, an antibody was isolated by immunoaffinity chromatography on immobilized PNA-receptors. The antibody reacted with the bovine interphotoreceptor matrix at the molecular weight of 130,000 daltons. Immunohistochemical studies revealed that the antibody was bound not only to the surfaces of the cone photoreceptor cells but also to the surfaces of the rods, suggesting that the antibody purified here may have been formed by the major structure of glycoprotein that is common in the interphotoreceptor matrix around the cones and rods.
A 4 1/2-year-old girl had a rapidly growing tumor in the orbit. An extirpated mass consisted of small round or spindle neoplastic cells containing hyperchromatic mitotic nuclei. The cytoplasm had many lipids and glycogens with few organelles. A light and electron microscopic examination revealed an exceptional tumor cell with distinct cross striations compatible with typical rhabdomyoblast; occasional cells exhibited a few bundles of thin filaments scattered in the cytoplasm. Immunohistochemical studies for muscle cell-related proteins by avidin-biotin-peroxidase complex methods revealed positive reactions of the tumor cells to the antiserum against myoglobin, myosin, desmin and vimentin, providing evidence for muscle cell derivation of the neoplastic cells.