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Biomedical subjects

O Tanaka

Publications and source records attributed to O Tanaka.

At least 235 records · Page 13Linked to original sources
PubMed1988

Development of the choroid plexus anlage and supraependymal structures in the fourth ventricular roof plate of human embryos: scanning electron microscopic observations.

The developing anlage of the choroid plexus and supraependymal structures in the fourth ventricular roof plates of nine normal human embryos ranging from Carnegie stages 14 to 19 were investigated with scanning electron microscopy. In the human embryos at stage 18, the first semimacroscopic choroidal anlage developed in the form of bilateral evaginations that ran dorsomedially and caudally from the bilateral corners of the rhombencephalon. The anlage became evident with even smaller and parallel ridges in the embryo at stage 19. Embryos at earlier stages exhibited surface membrane modifications such as convexity, microvilli, cilia, and spherical protrusions at the middle one-third of the rhombencephalon, which corresponded to the future choroidal anlage region. Two morphologically different groups of supraependymal cells (SE cells) were elucidated throughout the stages examined. Type 1 SE cells has spindle or tear-drop-like bodies, frequently with one or more long cytoplasmic processes. Type 2 SE cells were globular, with numerous fine pseudopodial processes. Type 1 SE cells were distributed mainly at the future choroidal anlage regions or on the anlage itself and were less frequently located at the rostral end of the roof. We found no general pattern in the distribution of type 2 SE cells. Supraependymal fibers (SE fibers) were seen as fine processes that were distributed similarly to type 1 SE cells and extended transversely for a long distance.

Cell Differentiation↗
PubMed1988

Development of the notochord in human embryos: ultrastructural, histochemical, and immunohistochemical studies.

In the present study of the notochord, the specimens were 54 externally normal human embryos ranging between Carnegie stages 13 and 23. The following staining procedures were used: periodic acid-Schiff (PAS), modified method of PAS, alcian blue, colloidal iron, and toluidine blue. Routine electron microscopic techniques were used. Immunoreactivity of the notochord to alpha-enolase was also examined. The notochord cells were undifferentiated in stage 13 with few intracellular organelles. The microfibrils and deposition of acid mucopolysaccharides appeared in the notochordal sheath in stage 14. The characteristic relation of mitochondria with rough endoplasmic reticulum was observed. Golgi complexes increased in the perinuclear region in stage 15. The layer of microfibrils in the notochordal sheath initially separated from the notochord in stage 16. Glycogen, mucoprotein, neutral mucopolysaccharides, and glycolipids began to increase in the mesenchymal cells around the notochord, starting at stage 16. Acid mucopolysaccharides increased in the notochordal sheath and in the matrix of the precartilage area around the notochord as this embryonic stage advanced. It was also revealed that the immunoreactivity of the notochord to alpha-enolase remained constant during the embryonic period. The results show that the notochord is transformed from an apparently undifferentiated organ into an organ with secretory activity in stage 14, producing microfibrils and depositing acid mucoplysaccharides in the notochordal sheath. The immunoreactivity of the notochord to alpha- and gamma-enolase isoenzymes and the development of the notochord are discussed. This study was undertaken to provide additional information on the development of tumors of notochordal origin.

Embryo, Mammalian↗
PubMed1988

Development of mitochondrial helical sheath in the middle piece of the mouse spermatid tail: regular dispositions and synchronized changes.

Morphologic changes in the development of the mitochondrial helical sheath in the mouse spermatid tail were examined with the scanning electron microscope (SEM) using the osmium-DMSO-osmium method and classified into several stages. During late spermiogenesis, spherical mitochondria gathered around the forming spermatid tail. The shape of these mitochondria gradually changed from spheroid to long and rod-like. Mitochondria first were arranged in four longitudinal rows (stage 1) that twisted dextrally, and the mitochondria began to stagger (stage 2). They became elongated and arranged into a staggered pattern; they then attached to each other in an end-to-end fashion to form a sinistral double helix around the core of the axoneme (stage 3). These end-to-end contacts were observed in every second gyre on the four lines surrounding the core of the axoneme at stage 3. Mitochondria further elongated and end-on touching appeared with every third gyre on the five longitudinal lines that surround the core of the axoneme (stage 4). The direction of the helix, always sinistral, was clearly discernible only in the later stages. Disposition of the mitochondria in the spermatid tail was regular throughout development, which indicates that these mitochondria elongate simultaneously and also at the same rate. On any given cracked surface of the seminiferous tubule, spermatid tails with the same stage of mitochondria predominantly were observed. This ultrastructural finding appears compatible with the histologic synchronism, (termed the "wave") in differentiating germ cells.

Animals↗
PubMed1988

Secretory activity in the floor plate neuroepithelium of the developing human spinal cord: morphological evidence.

The developing spinal cord at the cervical and thoracic levels in 14 human embryos ranging from Carnegie stages 14 to 20 were examined with the electron microscope. The floor plate-forming cells contained numerous cytoplasmic organelles, such as rough endoplasmic reticulum (ER), Golgi apparatus, and well-developed junctional complexes between the adjacent cells. Microvilli and cilia were numerous at the apical surface of neuroepithelial cells in the floor plate, but few were found in the lateral walls. Periodic acid-Schiff-positive substances were predominantly present in the neuroepithelial cells of the floor plate. In all specimens examined, multivesicular structures were observed in the floor plate neuroepithelium, but not in other regions of the spinal cord. The number of multivesicular structures appeared to increase with embryonic age. These structures contained numerous small and translucent vesicles within an electron-dense matrix; most vesicles were 40-70 nm in diameter. It appeared that the envelope of the multivesicular structures was first formed by the fusion of smooth ER-like cisterns, followed by invagination of the envelope by the vesicular contents. Presumably, the mature multivesicular structures were subsequently translocated to peduncular processes and their contents released into the central canal lumen in an exocytotic manner. This morphological evidence suggests that the floor plate cells of the spinal cord may have secretory activity during embryonic development.

Epithelium↗
PubMed1988

Cardiac tumour in a neonate with tuberous sclerosis: echocardiographic demonstration and magnetic resonance imaging.

In a neonate with tuberous sclerosis, cardiac tumours were diagnosed by two-dimensional echocardiography and evaluated by electrocardiogram-gated magnetic resonance imaging (MRI). The tumour size, shape and mobility in the ventricular cavities were more precisely determined by two-dimensional echocardiography than electrocardiogram-gated MRI, while the extent of tumour mass at the apex was more clearly delineated by MRI. As two-dimensional echocardiography provides real-time imaging of cardiac anatomy without sedation, it is useful for initial evaluation of cardiac masses in neonates with genetic predisposition to tuberous sclerosis.

Echocardiography, Doppler↗
PubMed1988

Alkaline phosphatase activity of the IVth ventricular choroidal epithelium of rats during embryonic and neonatal development.

The cytochemical localization of alkaline phosphatase (AlPase) activity in the developing IVth ventricular choroidal epithelium was investigated in embryonic and neonatal rats. During the initial development of the choroidal primodium the flattened and/or cuboidal epithelial cells of the ventricular roof were changed to columnar cells with well-developed microvilli and apical tight junctions. When compared to AlPase activity on the lateral plasma membranes of the surrounding ependymal cells, these columnar cells of the choroidal primodium revealed activity on the lateral and luminal plasma membranes, but no activity was found on the basal surface of these cells. On the other hand, the epithelial cells in the neonatal choroid plexus showed a continuous morphological alteration from columnar cells with short microvilli to mature cuboidal cells with numerous long microvilli. AlPase activity in immature columnar cells was observed on all plasma membranes, except for the apical junctional area of the lateral surface. With maturing of the choroidal epithelial cells, the activity appeared to be eliminated from the lateral and luminal plasma membranes of the cuboidal cells, and mature choroidal epithelial cells showed activity on the basal surface only. These findings suggest that AlPase may play an important role in the membrane activity of epithelial cells differentiating between the primitive epithelial cells of the ventricular roof and the mature choroidal epithelial cells.

Alkaline Phosphatase↗
PubMed1988

[Surgical therapeutic problems of thoracic esophageal carcinoma with special reference to the postoperative recurrent type].

The purpose of this study is to analyze an actual status of postoperative recurrences and to discuss some problems in surgical treatment of patients with thoracic esophageal carcinoma. One hundred and one (21.8%) of 464 patients who underwent an esophagectomy for thoracic esophageal carcinoma were selected for this investigation. They were classified into three groups depending on the initial recurrent type of the cancerous lesions. 1. Lymphogenic type, consisting of 47 cases (46.5%) with the recurrence of the carcinoma. The cervical and upper-mediastinal lymph nodes were favorite sites of lymphogenic recurrence. 2. Hematogenous type, 42 cases (41.6%) with organic recurrence. Of these, pulmonary lesions were encountered in 19 patients (45.2%) and bone in 11 (26.2%). 3. Disseminating type, 12 cases (11.9%) with cancerous dissemination. All patients had the recurrent lesions on the pleura except one patient who had on the peritoneum. One of the characteristic features in the carcinoma of the thoracic esophagus seems to be high incidence of lymphogenic and hematogenous recurrences. It should be, therefore, taken in consideration to perform a systematic radical lymphadenectomy and to devise an effective multidisciplinary treatment combined with surgery.

Esophageal Neoplasms↗
PubMed1988

Release of thromboxane A2 by low-dose almitrine in the hypoxic dog.

Potentiation of hypoxic pulmonary vasoconstriction by a low dose of almitrine bismesylate (1 microgram.kg-1.min-1) was evaluated in terms of blood chemical mediator concentrations. Time course changes in the blood concentrations of adrenaline, noradrenaline, serotonin, histamine, thromboxane TXB2 and 6-keto-PGF1 alpha were monitored after administration of almitrine bismesylate for 15 min at 1 microgram.kg-1.min-1) in hypoxic and normoxic beagles. The low almitrine dose significantly increased TXB2 levels in hypoxic beagles, but the levels remained virtually unchanged in the normoxic animals with almitrine bismesylate and in the hypoxic animals with solvent. TXB2 levels did not increase when the almitrine infusion was increased to 5 micrograms.kg-1.min-1 for 15 min in hypoxic conditions. These findings suggest that almitrine is involved in arachidonic acid metabolism at a low rate of infusion and that thromboxane release from hypoxic areas of the lung may cause local vasoconstriction.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

[Remarkable effect of vindesine sulfate (VDS) in the treatment of metachronous lung metastasis of esophageal cancer--a case report].

A case of metachronous lung metastasis treated by intravenous administration of VDS after esophageal cancer surgery is reported. A 63-year-old man who had undergone intrathoracic esophagectomy for cancer of the esophagus was shown to have a coin lesion in the middle lobe of the right lung on X-ray examination about one year after surgery. The schedule for intravenous administration of VDS was 5 mg/body every week. The metastatic lesion disappeared after a series VDS administrations totalling 35 mg. Major side effects such as leukopenia and fever were occasionally observed during the course of drug administration. The patient required three occasions of hospitalization for these adverse effects. It is thus emphasized that an effect of VDS may be expected for hematogenous dissemination of esophageal cancer.

Carcinoma, Squamous Cell↗