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Biomedical subjects

Y Sano

Publications and source records attributed to Y Sano.

At least 415 records · Page 23Linked to original sources
PubMed1982

Immunohistochemical studies on the processes of serotonin neurons and their ramification in the central nervous system--with regard to the possibility of the existence of Golgi's rete nervosa diffusa.

Using various vertebrates from teleost to macacus, we studied, by the modified PAP method, the serotonin neurons that are distributed mainly in the raphe nuclei area, focussing on their process ramifications, and obtained the following results. 1. The shapes of serotonin neurons were varied. They were multipolar with many long, thick dendrites. In most of the neurons, more than two axons originated either from the stem of a dendrite or from its tip. 2. The axons contained spherical or spindle-shaped varicosities of varied sizes (diameter 0.5-6 micron). On a few occasions, they became large, Herring body-like droplets. 3. The axons were classified into four groups according to the shape and size of the varicosities they contained: stem fibers, A-fibers (tract fibers), B-fibers (branching fibers) and C-fibers (ground fibers). 4. The axon not only branched frequently, but formed a true network by way of frequent anastomosis at the level of B- and C-fibers. Serotonin fibers do not have endings that correspond to telodendrons, but conduct impulses through "en passant" type synapses. 5. A supraependymal plexus is formed over large areas of the ventricular system. This vast network is considered to be formed by the syncytial continuity of axonal reticulum of many serotonin neurons. 6. Serotonin neurons, and probably noradrenaline neurons as well, should be classified as a third type of neuron, which belong to neither the Deiters type nor the Golgi type neuron. Their characteristic feature is the long, reticular axons, and it is highly probable that this neuron system forms the "rete nervosa diffusa" proposed by GOLGI.

Animals↗
PubMed1982

[Part I. Theory and computer simulation for cerebrospinal infusion].

A pharmacokinetic one-compartment model for the cerebrospinal infusion for the brain tumor chemotherapy is described together with various parameters used for computer simulation. An antitumor protein, neocarzinostatin (NCS) as a prototype drug, has been utilized since it was found effective against glioblastoma cells at extremely low concentration (less than 5 ng/ml) and it is readily inactivated by serum. A very slow infusion velocity was found necessary for an appropriate dose regimen; for example, 0.25mg of the drug should be infused into CSF for about 40 min to attain a drug level of 8 ng/ml.

Antibiotics, Antineoplastic↗
PubMed1982

Factors that influence initiation and growth of 9L rat brain gliosarcoma multicellular spheroids.

This report details optimum conditions for initiating and growing 9L rat brain gliosarcoma multicellular spheroids. Best results were achieved when 0.5 to 2.0 x 10(6) cells were seeded initially into agarose (0.5 to 1.0%)-coated Petri dishes. Spheroids initiated in this manner appeared to grow in spinner culture at a rate slightly faster than spheroids initiated and grown in spinner culture. An optimum growth rate was obtained for individual spheroids grown in the well of cluster dishes coated with 0.5 to 0.75% agarose in growth medium containing 10% newborn calf serum and 0.9 g glucose per liter. Three methods for dissociation of spheroids at both room temperature and 37 degrees have been developed. The "race track" method of fractional dissociation produced a constant and similar number of cells for each disaggregation interval, and the plating efficiency of cells in each fraction was similar.

Animals↗
PubMed1981

Hereditary deficiency of the third component of complement in two sisters with systemic lupus erythematosus-like symptoms.

We observed two sisters with lupus-like syndrome with homozygous C3 deficiencies. A 19-year-old woman and her 15-year-old sister developed malar rash, arthralgia, and photosensitivity, but antinuclear antibodies and LE cell preparations were negative. The older sister experienced recurrent bronchitis in her childhood, but the younger sister had no recurrent infections. Serum C3 was not detected immunochemically in either sister, and total complement activity and C3 hemolytic activity were extremely low.

Adolescent↗
PubMed1981

Cells capable of uptake of horseradish peroxidase in some circumventricular organs of the cat and rat.

The structure of mesenchymal cells distributed in some of the "hypendymal organs" of the circumventricular system in the cat and rat was demonstrated after intravenous injection of high doses of horseradish peroxidase. These cellular elements were observed in the vicinity of blood vessels of the organon vasculosum laminae terminalis, subfornical organ and area postrema. Electron-microscopically, these cells located between the basal laminae of the brain parenchyma and the blood capillaries show long cellular processes encircling fenestrated capillaries. Light- and electron-microscopic examination revealed that this cell type is identical with the "horseradish peroxidase-uptake cells,", previously reported in the vicinity of the hypophysial portal system. Such phagocytic cells may be considered as a cellular component intervening between the brain parenchyma and the blood stream, playing a role in selective barrier functions in the above-mentioned circumventricular organs where a blood-brain barrier in the classical sense of the definition is lacking.

Animals↗
PubMed1981

Morphological studies on neuroglia. III. Macrophage response and "microgliocytosis" in kainic acid-induced lesions.

Light- and electron-microscopic investigations of kainic acid-induced lesions revealed a marked macrophage response and "microgliocytosis". The hematogenous origin of reactive elements, such as brain macrophages and "'microglia-like reactive cells", was demonstrated when blood phagocytes were labeled with carbon particles or horseradish peroxidase prior to induction of the kainic acid-lesion. The induced lesion showed a proliferation of microglial cells, which led to a state of "microgliocytosis" in the later stage of lesioning. Since it is now generally accepted that microglial cells in the state of "microgliocytosis" are derived from the "microglia-like reactive cells", proliferated microglial cells in the brain lesions are probably of hematogenous origin. The relationships among the brain macrophages, the "microglia-like reactive cells" and the intrinsic microglial cells are discussed.

Animals↗
PubMed1981

Correlative ontogenetic development of catecholamine- and LHRH-containing nerve endings in the median eminence of the rat.

The ontogenetic development of catecholamine (CA)- and LHRH-containing nerve endings in the median eminence of the rat was investigated by combining fluorescence histochemistry and immunohistochemistry in the same tissue section. LHRH-terminals appeared earlier than CA-terminals and were already detectable in the lateral part of the external layer of the central ME on the first day after birth. CA-nerve endings were first seen in a corresponding region of the ME on the seventh postnatal day. At this stage both types of terminals showed the earliest manifestation of a correlative pattern of their distribution. Subsequently the development of both types of nerve endings proceeded rapidly, and at 14 days their distribution pattern corresponded to that in adult animals. The authors conclude that at this stage the CA-neurons play a constant and significant role in the release of LHRH into the portal capillaries. The correlation between both types of nerve endings and the ontogenetic development of the capillary plexuses of the hypophysial portal system is discussed.

Age Factors↗
PubMed1981

Morphological studies on neuroglia. II. Response of glial cells to kainic acid-induced lesions.

The cellular response of non-neuronal elements of the pyramidal cell layer of the rat hippocampus, especially the area CA3, was observed electron microscopically following destruction of this formation by means of intraventricular administration of kainic acid (KA). The neuroglial cell types responding to the KA-induced lesion included astrocytes and the "microglia-like reactive cells". In addition, numerous brain macrophages appeared in the damaged area CA3. Oligodendrocytes and pericytes revealed no morphological changes. Swollen astrocytes were seen in the KA-induced lesion during the early stage. Glial filaments gradually developed in the soma and cell processes of these cells. Brain macrophages were seen in the KA-induced lesion during the early stage; they gradually decreased in number with time. Numerous small cells displaying a dark nucleus appeared in the damaged area CA3 during the first two days after the KA-administration, and gradually increased in number. During the later stage this cell type could hardly be distinguished from the intrinsic microglial cells. It is open to discussion whether this cell type originates from the intrinsic microglial cells or from the hematogenic monocytes; therefore it is designated as "microglia-like reactive cell" in the present study.

Animals↗
PubMed1981

A pharmacokinetic simulation model for chemotherapy of brain tumor with an antitumor protein antibiotic, neocarzinostatin. Theoretical considerations behind a two-compartment model for continuous infusion via an internal carotid artery.

A pharmacokinetic two-compartment model for the treatment of brain tumors in man was simulated with the aid of a computer. The parameters necessary for the simulations such as inactivation rate constant, elimination rate constant, distribution volume, blood volume, cerebral blood flow, and cytotoxic drug concentration were either determined in this study or obtained from the literature. A proteinaceous antitumor antibiotic, neocarzinostatin (NCS), was utilized as a prototype drug because it has features making it advantageous in the treatment of brain tumor. In particular, NCS has an extremely short half-life in serum (t 1/2 less than or equal to 3 s), while it is relatively stable in the cerebrospinal fluid (CSF) (t 1/2 approximately 50 s). Therefore, the drug level in the cerebral compartment can be made adequately high with an appropriate infusion velocity into the cerebral compartment; however, it was possible to keep the plasma level of the drug much lower than the toxic level. Thus, few side-effects should result. In an in vitro study, NCS was found to exhibit its cytotoxicity to glioblastoma cells at a concentration as low as 0.005 microgram/ml. In contrast, the cytotoxicity was not apparent for the normal glia cells at 0.1 microgram/ml. The model being considered in this investigation is a two-compartment model, which consists of the cerebral compartment and the rest of the circulatory system of the body. In this case the drug is infused via an internal carotid artery. The results of pharmacokinetic simulation and dose regimens for NCs are presented, based on the effective concentration of the drug to glioblastoma cells in culture and the available pharmacological parameters.

Antibiotics, Antineoplastic↗
PubMed1981

Thiaminepyrophosphatase activity in the plasma membrane of microglia.

An intense thiaminepyrophosphatase (TPPase) activity was demonstrated in glial cells and blood vessels in the central nervous system (CNS), when incubation was carried out with thiaminepyrophosphte (TPP, cocarboxylase), using the method of Novikoff and Goldfischer (1961). Glial cells with TPPSase activity were identified as microglia because they were morphologically similar to microglial cells in the sections stained with silver impregnation. TPPase activity was localized in the microglial perikaryon and in the processes, as viewed under a light microscope. Electron microscopically, enzyme activity was localized in the plasma membrane of microglia. We consider this activity to be a true TPPase activity hydrolyzing TPP, and we then went on to examine the substrate specificity, optimum pH, effect of chemical inhibitors and activators, and the effect of glutaraldehyde fixation. Our data are reported herein.

Animals↗
PubMed1981

Effect of monovalent cations on the aggregation of tobacco mosaic virus by chondroitin sulfate.

The mechanism of precipitation of tobacco mosaic virus by chondroitin sulfate in the presence of various monovalent cations was investigated kinetically by means of turbidimetry. The virus solution became turbid on the addition of chondroitin sulfate, and led to separation of the virus as a crystalline phase. In the presence of monovalent cations the degree of precipitation of the virus by chondroitin was reduced with the increase in monovalent cation concentration. The order of the reduction was Li+ less than Na+ less than K+, which is reversely analogous to the lyotropic series. The least hydrated cation, K+, reduced the degree of precipitation of tobacco mosaic virus the most because the radius of the sphere equivalent to chondroitin sulfate was diminished most strongly by K+ ion. The effect of the monovalent cations on the precipitation supports our assumption that the virus precipitation results from incompatibility and mutual spatial exclusion between the virus and chondroitin. The maximum turbidities, the initial slopes, and the aggregation half-time were measured by varying the monovalent cation concentrations. The former two parameters decreased with the increase in cation concentration, whereas the aggregation half-time increased. A lag time was present and the effect of the cations increased in the order K+ less than Na+ less than Li+.

Chemical Phenomena↗