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Biomedical subjects

E Tani

Publications and source records attributed to E Tani.

At least 145 records · Page 8Linked to original sources
PubMed1977

Tight junctions of oligodendrocytes.

Freeze-fracture replicas of the rat corpus callosum revealed prominent junctional strands in fractured cell membranes of the somata of oligodendrocytes. The junctional strands were characterized by an elaborate system of straight or slightly undulating rows of linear aggregates of particles or ridges in the P face and furrows in the E face.

Animals↗
PubMed1977

Membrane structures of human oligodendroglioma.

Plasma membrane particles of four human oligodendrogliomas were distributed at random, and their average number per micronm2 plasma membrane was 1090+/-233 on face A and 230+/-46 on face B. Gap junction was occasionally visible, usually small in size and composed of a polygonal aggregate of several subunits: isodiametric particles, about 70-80 A in diameter, on face A and pits, about 30-40 A in diameter, on face B. Tight junction in two oligodendrogliomas was characterized by a meshwork of circular or ramifying crests on face A and complementary furrows on face B. It was often continuous in distribution, consisting of 5 or more strands. In addition, many particulate structures, occasionally fibrillar ones, of ridge materials were often visible in the bottoms of furrows, and a few particles were scatteredly found on the tops of crests. The ridge materials, if added together on crests and furrows, were linearly continuous in some case and discontinuous in other.

Brain Neoplasms↗
PubMed1977

Cell membrane structure of vascular smooth muscle of circle of Willis.

Cell membranes of vascular smooth muscles of the circle of Willis were studied in thin sections and freeze-replicas. The cell membranes were differentiated into a caveolae intracellulares zone and caveolae-free zone, both of which were generally arranged in an alternate manner and parallel to the major axis of the smooth muscle cell. In the former zone, the caveolae intracellulares, about 600 A in diameter, were neatly oriented in one to several rows running parallel to the longitudinal axis of the muscle cell with a center-to center distance of about 800 A. The latter zone was of variable width and smooth, apart from membrane particles or scattered caveolae, and corresponded mainly to the dense area and partially to the myofibril area beneath the cell membrane. Membrane particles were generally more numerous on face A than on face B, and their average number per micronm2 was about twice as many inside the rows of the caveolae as outside. Rosette formations of membrane particles were often evident at the stomal rims of the caveolae. Adherentes and gap junctins were occasionally found on the caveolae-free areas which often protruded externally. Tight junctions appeared as a collection of scattered strands, which frequently showed free ends and were parallel to each other and also to the major axis of the smooth muscle cell.

Animals↗
PubMed1977

Freeze-fracture of capillary endothelium in rat brain.

The rat brain capillary was studied with freeze-fracture technique. The attached plasmalemmal vesicles were quite few in number on the luminal front and sometimes numerous on the contraluminal side. The fracture appearance of some tight junctions showed interconnecting ridges on face A and complementary furrows devoid of particles on face B, comparable to the common tight junction in the normal epithelia. Other tight junctions revealed a preferential disposition of quasicontinous rows of particles on shallow furrows of face B, resembling the tight junctional strands of capillary endothelium in non-cerebral tissues. Either behavior is probably due to the difference in the fracture plane around the single fibril. In addition, the tight junctional strand could surround the perimeter of the endothelial cell completely although the exposed strand of tight junction was limited in lenght.

Animals↗
PubMed1976

Aggregated plasmalemmal vesicles and microvilli in human astrocytoma.

Plasmalemmal vesicles and microvilli or filopodia in human astrocytoma were examined with thin-section and freeze-fracture techniques. The plasmalemmal vesicles, although sparsely scattered in distribution, were often aggregated in a curvilinear, semicircular, or circular fashion, and the involved plasma membrane was often protruded externally like a mound. Microvilli or filopodia were cross-fractured when fracture travelled within the plasma membrane resulting in a fracture face interrupted by numerous holes of cytoplasms. The microvilli were distributed in a concentrated manner on the free surface of the cell and often closely oriented in a linear, curvilinear, or circular fashion. They varied in size, form, and length. When they were arisen from a common hillock of the plasma membrane, its fracture face was elongated, up to 0.8 mu in length. Fenestrae were occasionally visible in attenuated cytoplasm which surrounded peripheral vacuole in the cell.

Astrocytoma↗
PubMed1975

Plasma membrane structures of medulloblastoma and cerebellar sarcoma.

Three medulloblastomas and 1 cerebellar sarcoma were studied on their plasma membrane structures. The average number of membrane particles per mum2 plasma membrane was 710 on face A and 70 on face B of medulloblastoma and 1280 on face A and 160 on face B of cerebellar sarcoma. The membrane particles were often aggregated in medulloblastoma and diffusely scattered in cerebellar sarcoma. Small gap junctions were occasionally found in cerebellar sarcoma and not evident in medulloblastoma. Round membrane protrusions, about 0.5-0.6 mu in diameter and provided with several small depressions on their foot, were often observed in region of narrow perinuclear cytoplasm of cerebellar sarcoma and different in structure from cytoplasmic processes. The present series is too limited in number to allow a definite conclusion, but indicates that the plasma membrane structures are different in medulloblastoma and cerebellar sarcoma.

Cell Membrane↗
PubMed1975

Nuclear characteristics of malignant lymphoma in the brain.

In addition to chromatin and nucleoli, various classes of structures were often seen in nuclei of malignant lymphoma, when compared with other brain tumours. Interchromatin, perichromatin, and atypical dense granules could be ribonucleoprotein in nature on basis of their behaviours in enzymatic extraction and EDTA stain. The perichromatin fibrils became visible at the border of the condensed chromatin only after EDTA stain and might contain substrate for HnRNA. Nuclear bodies and intranuclear fibrillar rodlets also were evident.

Brain Neoplasms↗
PubMed1975

Fenestrae in golgi and endoplasmic reticulum cisternae of human brain tumours.

Fenestrae were found in freeze-fractured cisternae of the Golgi apparatus and endoplasmic reticulum of glioblastoma, oligodendroglioma, ependymoma, medulloblastoma, medulloepithelioma, meningioma, cerebellar sarcoma, hemangioblastoma, and chromophobe adenoma. They were about 200--400 A in diameter and often diffusely distributed or concentrated in groups in Golgi cisternae, while they were around 300--600 A in size and scattered in distribution in cisternae of endoplasmic reticulum. They appeared as conical protrusions or circular broken-off necks of face A and as circular holes on face B in tangential fractures, and as several constrictions of cisternae in cross fractures.

Adenoma, Chromophobe↗
PubMed1975

Freeze-fracture study of human brain tumors.

This freeze-fracture study was performed in 3 astrocytomas, 6 glioblastomas, 2 ependymomas, 3 medulloblastomas, 1 cerebellar sarcoma, 3 germinomas, and 1 medulloepithelioma. The number of nuclear pores/mum2 nuclear membrane was not correlated with biological malignancy. Fracture faces A and B were discernible in nuclear, Golgi and rough endoplasmic reticulum (ER), mitochondrial surface, and plasma membranes. Fenestrae were evident in Golgi and ER membranes. The transitional zone of cristae from the inner surface membrane appeared as a circular hole and broken-off neck on faces A and B of the inner surface membrane, respectively. The decrease in number of membrane particles in the plasma membrane seemed to correlate with the frequency of metastases, and, in addition, the membrane particles appeared to cluster in glioblastoma, medulloblastoma, and medulloepithelioma. The gap junctions were abundant in astrocytomas, moderate in number in ependymomas and germinomas, and rare in glioblastomas, cerebellar sarcoma, and medulloepithelioma. Tight junctions were often found in germinomas and medulloepithelioma, and rarely in ependymomas.

Astrocytoma↗