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Biomedical subjects

S Aida

Publications and source records attributed to S Aida.

At least 109 records · Page 6Linked to original sources
PubMed1977

Dishabituation of mesencephalic reticular neurons by anesthetics.

To determine whether neuronal firing is affected by anesthetics, the behavior of neurons in the mesencephalic reticular formation in response to repetitive somatosensory stimulation at 2/sec was studied during wakefulness and during nitrous oxide, halothane, and thiopental anesthesia in the cat. With clinical doses of the three anesthetics there were simultaneous blockades of both initial facilitation (28 of 32) and subsequent habituation (31 of 32) of the evoked responses in a majority of the mesencephalic reticular formation neurons. This dishabituation phenomenon was most prominent with thiopental and least prominent with nitrous oxide. Thus, it is suggested that progressive inactivation of not only the facilitatory process but also the inhibitory process in the neuronal activities of the mesencephalic reticular formation is associated with the so-called "anesthetic state" produced by these three anesthetics.

Anesthetics↗
PubMed1976

Interactions of human cord dorsum potential.

The slow positive wave (P2 wave) of the evoked spinal electrogram was recorded from the posterior epidural space in wakeful man, and studied by applying several modes of peripheral nerve stimulation. With graded stimulation the P2 wave amplitude rapidly reached the maximum at weaker stimulation than that required for the initially positive spikes (P1) and the preceding negative (N1) wave. The "second" component of the P2 appeared during stronger stimulation or during excitemenpt of the subjects. With prolonged repetitive stimulation the P2 wave increased its duration with several summits on the decaying phase. Two interactions were observed between the P2 waves produced by conditioning and testing stimulations in the same or different nerves: inhibition or occlusion by strong stimulation and faciliation by weak stimulation. Thus, the characteristic of the P2 wave in man was similar in part to that of the positive wave observed in decerebrate animals, and differnt in other ways presumably due to influences from supraspinal structures or species differences.

Adult↗
PubMedDate not supplied

Sinonasal teratocarcinosarcoma: ultrastructural and immunohistochemical evidence of neuroectodermal origin.

The authors report a case of sinonasal teratocarcinosarcoma in a 37-year-old man, which was located in the anterior skull base and extended to the right nasal cavity and paranasal sinuses. The tumor was surgically resected twice, but it could not be removed completely. Microscopically, it was mainly composed of primitive cell nests within a moderately cellular stroma. The components of squamous cell epithelia with focal teratoid appearance and adenocarcinomatous differentiation were observed. There were many rhabdomyoblasts scattered in the nests and stroma. Ultrastructurally, the primitive cells had many neural processes with parallel microtubules, resembling olfactory neuroblastoma. Rhabdomyoblasts showed various degrees of skeletal muscle differentiation. Some of the stromal spindle cells had actin filaments with dense patches and dense core granules. Immunohistochemically, the primitive cells were positive for epithelial markers, neuron-specific enolase, synaptophysin, and myogenic regulatory proteins. The rhabdomyoblasts showed immunoreactivity for myoid markers, cytokeratin, epithelial membrane antigen, and synaptophysin. Most of the stromal spindle cells were positive for smooth muscle actin, neuron-specific enolase and synaptophysin. The immunohistochemical and ultrastructural findings suggest that primitive cells had the most primitive phenotype of placodes, and support the possibility that sinonasal teratocarcinosarcoma is essentially a neuroectodermal tumor with divergent differentiation.

Adult↗
PubMedDate not supplied

Renal oncocytoma with intracytoplasmic lumina: a case report with ultrastructural findings of "oncoblasts".

The authors present a case of renal oncocytoma with numerous intracytoplasmic lumina in a 45-year-old woman, with an emphasis on the ultrastructural findings of so-called oncoblasts. The tumor was located in the upper pole of the left kidney, measuring about 3.3 cm in diameter. Histologically, it was composed of solid nests or acinar growths of so-called oncocytic tumor cells with numerous intracytoplasmic lumina and scattered foci of so-called oncoblasts. The luminal surface was positive for Hale's colloidal iron stain. A very small number of glycogen-containing cells were found scattered in a few nests. Immunohistochemically, tumor cells were positive for cytokeratin and epithelial membrane antigen, but negative for vimentin and carcinoembryonic antigen. The Ki-67 labeling index was 1.2%. All of the Ki-67-positive cells were oncocytes. So-called oncoblasts were negative for Ki-67. Ultrastructural examination revealed that the predominant tumor cells had cytoplasm packed with round mitochondria and the mitochodria had lamellar long cristae. So-called oncoblasts showed scant cytoplasm with a moderate number of small mitochondria. Some of them showed pyknosis which can be regarded as mitochondrial involution. The authors believe that so-called oncoblasts are damaged or involuted oncocytes rather than precursors of oncocytes.

Adenoma, Oxyphilic↗
PubMedDate not supplied

Preoperative needle biopsy and immunohistochemical analysis for gastrointestinal stromal tumor of the rectum mimicking vaginal leiomyoma.

Accurate preoperative diagnosis for gastrointestinal stromal tumor (GIST) was obtained using the endoscopic approach in about 50% of the cases. Preoperative assessment is quite important in reproductive women for the treatment of pelvic tumor. We report the first case of GIST of the rectum that was accurately diagnosed with preoperative needle biopsy from the vaginal wall. The case was a 38-year-old woman who presented with a history of genital bleeding. Internal examination revealed a round and elastic mass (7 x 7 cm) in the left pelvic cavity. The biopsy specimen from the left sidewall of the vagina using a manually manipulated biopsy needle showed strong reaction for CD34 and CD117 (c-KIT). The patient underwent low anterior resection of the rectum, tumor resection, and partial resection of the posterior vagina. Preoperative biopsy with vaginal approach might be helpful to make a diagnosis for pelvic tumor of unknown origin and unknown malignant potential.

Adult↗