Biomedical subjects

S Nishio

Publications and source records attributed to S Nishio.

364 records · Page 21Linked to original sources

PubMedDate not supplied

Effect of beraprost sodium on changes in action potentials during hypoxia as compared with propranolol, diltiazem and glibenclamide in guinea-pig ventricular muscle.

The inhibitory effect of beraprost on the transmembrane action potentials was compared with other cardioprotective drugs during hypoxia in guinea-pig isolated right ventricular muscle. Glibenclamide, like beraprost, inhibited the decrease of the action potential duration, but propanolol and diltiazem did not affect this decrease during hypoxia. In beraprost-treated preparations, the decrease of the myocardial K+ content during hypoxia was inhibited. Furthermore, beraprost prevented the action potential shortening during metabolic inhibition by 2,4-dinitrophenol. It is suggested that beraprost may inhibit the hypoxia- and 2,4-dinitrophenol-induced shortening of the action potential duration by preserving the muscular ATP level. Accordingly, beraprost may have beneficial effects both during hypoxia and metabolic inhibition.

2,4-Dinitrophenol↗

PubMedDate not supplied

Microcystic meningioma: tumors of arachnoid cap vs trabecular cells.

Three unusual meningiomas with extensive microcystic formation were studied by light- and electron-microscopy. The tumor cells in the first and second cases had many morphological characteristics in common with the arachnoid cap cells: prominent and complex interdigitation of the fine cytoplasmic processes, numerous well developed desmosome attachments, and intracytoplasmic microfilaments. The prominent features of these tumors were a marked vascularization and hyaline thickening of the vessel walls, and the microcystic formation was considered to be related to these changes. In contrast, the tumor cells of the last case had characteristic structures in common with trabecular arachnoid cells. They were stellate in shape, and had only a small number of intracytoplasmic filaments. Arborizing relatively thick and long cytoplasmic processes showed simple junctions with occasional desmosomes, and delimitated microcysts. The tumor cells in this case were considered to recapitulate the subarachnoid structure and formed microcysts. Although the histogenesis of microcysts in meningiomas is not considered to be uniform, the biological behavior of these 3 tumors corresponded to those of meningiomas in general.

Adult↗

PubMedDate not supplied

Posterior trapezius myocutaneous flap.

Since last decade, myocutaneous flaps have appeared among the most versatile and safest options for the reconstruction of defects caused by large oncological resections, in the head and neck area. Undoubtedly, the myocutaneous flap of the pectoralis major muscle is the most widespread and accepted, due to the long experience obtained through its use. Nevertheless, it presents some restrictions related not only to its rotation arch, but also to the esthetic consequences for the donor site in females. Over the last years, there has been a growing interest in the posterior trapezius myocutaneous flap (PTMF), which proved to be a valuable alternative for reconstruction in selected cases. The experience of the Department of Head and Neck Surgery, at the University of São Paulo Medical School-Hospital das Clínicas, using this technique, is reported here in a detailed description.

Basal Cell Carcinoma↗

PubMedDate not supplied

Immunohistochemical expression of tyrosine kinase (Trk) receptor proteins in mature neuronal cell tumors of the central nervous system.

The interactions of neurotrophins with the Trk family of tyrosine kinase receptors result in growth and maturational changes in neuronal cells. Although the histogenesis of brain tumors composed of mature neuronal cells is still not completely understood, neurotrophins and Trk receptors may be involved in the evolution, maturation, and persistence of these tumors. The clinical and anatomic pathological features of 8 primary neuronal cell tumors (ganglioglioma: 3 cases, cerebral neurocytoma: 3 cases, intraventricular neurocytoma: 2 cases) occurring in the central nervous system (CNS) have been examined. In addition to routine histological examinations, immunohistochemistry was used to evaluate the expression of neurotrophin receptors (TrkA, TrkB) and of neuronal differentiation markers such as neuron-specific enolase, neurofilament, synaptophysin, and chromogranin A. While neither TrkA nor TrkB expression was demonstrated in 2 intraventricular neurocytomas, the remaining 6 tumors did show positive immunohistochemical staining for TrkA and/or TrkB proteins; for TrkA protein, ganglionic cells showed membraneous or cytoplasmic staining, while small non-ganglionic neuronal cells with scant cytoplasm occasionally showed positive cytoplasmic immunoreactivity. For TrkB protein, small non-ganglionic neuronal cells showed a more intense immunoreaction than ganglionic cells. Gangliogliomas with high TrkA and TrkB expression showed higher levels of neuronal differentiation, as demonstrated by the neuron-specific enolase and neurofilament immunoreactivity. The existence of neurotrophin receptors in the tumor cells thus suggests that neurotrophic influence are involved in the evolution and subsequent cellular maturation in neuronal cell tumors of the CNS.

Adult↗