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Biomedical subjects

N Takeda

Publications and source records attributed to N Takeda.

At least 559 records · Page 31Linked to original sources
PubMed1984

Fine structure of histaminergic neurons in the caudal magnocellular nucleus of the rat as demonstrated by immunocytochemistry using histidine decarboxylase as a marker.

The morphology of histamine-containing neurons in the caudal magnocellular nucleus was light and electron microscopically examined by means of peroxidase-antiperoxidase (PAP) immunocytochemistry with histidine decarboxylase (HDC) as a marker. HDC-like immunoreactive (HDCI) neurons had large (25-30 microns in diameter) perikarya from which two to four primary dendrites arose. The perikarya had a nearly round nucleus and well-developed Golgi apparatus in addition to a large number of mitochondria and rough endoplasmic reticulum. Immunoreactive endproducts were found diffusely throughout the perikarya, dendrites, and axons. HDCI neurons made synaptic contact with nonreactive axon terminals on the perikarya and dendrites. In addition, the HDCI neurons very frequently formed puncta adherentia with neuronal elements, either HDCI or nonreactive, or glial cells. Most of the HDCI axon terminals serially observed under electron microscopy did not exhibit typical synaptic contact in the caudal magnocellular nucleus. These findings suggest the nonsynaptic release of histamine in the caudal magnocellular nucleus.

Animals↗
PubMed1984

Evolution of enterovirus type 70: oligonucleotide mapping analysis of RNA genome.

Different isolates of enterovirus type 70 (EV70) taken between 1971 and 1981 were studied by molecular biological methods to elucidate their evolutional change. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that only a few isolates had a slight alteration in mobility in some viral proteins. On the contrary, oligonucleotide mapping of virion RNA could clearly delineate the molecular changes among isolates. The number of base changes of isolates became greater as the years elapsed. In addition, the number of base changes among recent isolates from different areas of the world was much greater than those among early isolates. Thus, when the isolates were arranged three-dimensionally according to the number of base changes between each other, the constellation of the strains gave rise to a conical shape. The central axis of the figure was the time of isolation of the strains. The early isolates clustered near the top of the conical figure and the recent isolates tended to disperse divergently at the bottom. The figure indicated that all EV70 strains were derived from a common ancestor, and its top would be the time of emergence of the original strain. It was estimated to be around 1966, 3 years prior to the first epidemic in Accra, Ghana. From the results, it was presumed that EV70 would have emerged at a single focus in Africa as a novel human virus. After having circulated there for a few years, the virus spread to the other parts of the world. Based on the difference in the oligonucleotide spots between the recent isolates and early isolates, the base changes of EV70 that occurred during 10 years was estimated to be 320, about 4% (0.4% a year on the average) of the bases of the total RNA genome.

Biological Evolution↗
PubMed1984

Immunohistochemical evidence for the coexistence of histidine decarboxylase-like and glutamate decarboxylase-like immunoreactivities in nerve cells of the magnocellular nucleus of the posterior hypothalamus of rats.

Immunohistochemical staining of alternate consecutive sections revealed numerous histidine decarboxylase (L-histidine carboxy-lyase, EC 4.1.1.22)-like immunoreactive neurons that also contained glutamate decarboxylase (L-glutamate 1-carboxy-lyase, EC 4.1.1.15)-like immunoreactive structures in the tuberal magnocellular nucleus, the caudal magnocellular nucleus, and the postmammillary caudal magnocellular nucleus of the posterior hypothalamus of rats. Furthermore, in immunohistochemical double-staining procedures, almost all neurons in the magnocellular nuclei had both histidine decarboxylase-like and glutamate decarboxylase-like immunoreactivities. These results suggest the coexistence of histamine and gamma-aminobutyric acid in single neurons in these nuclei.

Animals↗
PubMed1984

Cardiac alterations at the myofibrillar level: is a redistribution of the myosin isoenzyme pattern decisive for cardiac failure in haemodynamic overload?

Cardiac muscle physiology, cardiac dynamics and energetics of normotensive and hypertensive rats [Goldblatt II, spontaneously hypertensive rats (SHR)] are analyzed in the light of the question of whether a shift in the isoenzyme pattern of myosin in favour of the isoenzyme VM-3--i.e., transformation towards a slower muscle--is the essential factor for manifestation of cardiac insufficiency under chronic haemodynamic overload. Earlier investigations on chemically skinned myocardial preparations with homogeneous VM-3 and VM-1 patterns revealed that the decrease in unloaded shortening velocity attributable to extreme redistribution of the isoenzyme pattern can amount to approx. 40% whereas isometric tension development at the myofibrillar level is not significantly reduced. Findings from old normotensive and spontaneously hypertensive rates show that even substantial prevalence of VM-3 permits adequate ventricular pumping function. The decrease in the systolic parameters observed in later stages of chronic pressure overload may be attributed primarily to regressive alterations (fibrosis, structural dilatation). Under chronic haemodynamic overload, experimentally imposed isoenzyme redistribution towards a faster myocardium (small thyroxine doses) as well as transformation towards a slower muscle (thyrostatic treatment) affects the time parameters of contraction and oxygen consumption more than left ventricular work capacity. Signs of congestive heart failure are absent. It is concluded that mere transformation of myocardium towards a more slowly functioning muscle should not be considered the cause of cardiac failure in the rat model although this adaptive process may have detrimental consequences under certain conditions.

Adenosine Triphosphatases↗
PubMed1984

Characterization of a temperature-sensitive defect of enterovirus 70: effect of elevated temperature on in vitro transcription.

A crude replication complex prepared from enterovirus 70-infected cells was used to study the temperature-sensitive characteristic of the virus. The complex showed a temperature sensitivity in the in vitro incorporation of radiolabeled ribonucleoside triphosphate. The endonuclease itself did not account for the restricted RNA synthesis at the nonpermissive temperature. Analyses of the in vitro products by both gel electrophoresis and sucrose density gradient centrifugation showed that the complex synthesized three types of viral RNA only when incubated for a short period of time at the nonpermissive temperature. When the replication complex was treated with a detergent (deoxycholic acid), incorporation of ribonucleoside triphosphate into RNA at the permissive temperature was reduced to the level of that at the nonpermissive temperature. In addition, the in vitro RNA synthesis by the enterovirus 70 replication complex at the permissive temperature required a higher concentration of ATP than of other ribonucleoside triphosphates, whereas such a preference for ATP was not found in the reaction at the nonpermissive temperature. The results indicate that the initiation step of RNA synthesis by the complex is blocked at the nonpermissive temperature. The possible implications of these findings are discussed.

Adenosine Triphosphate↗
PubMed1984

CT findings of medulloblastoma.

Computed tomography (CT) of 11 patients with medulloblastoma was evaluated. 6 of them showed solid, nearly homogenous lesions and definite enhancement after infusion of contrast medium. However, 5 cases showed heterogenous mass lesions composed of the areas of low density and iso- or slightly high density which was attenuated by contrast enhancement. Histological examinations revealed that 2 cases had differentiated medulloblastomas, but the other 3 typical medulloblastomas. It should be reminded in the differential diagnosis of cerebellar tumors of pediatric patients that medulloblastoma can reveal heterogenous mass in CT scan.

Cerebellar Neoplasms↗
PubMed1984

[Delayed radiation necrosis in the optochiasmatic region--report of two cases and review of the literature].

Two cases with delayed radiation necrosis of the chiasmatic region following irradiation of the hypophysis for treatment of Cushing's disease were presented. Case 1 was a 36-year-old female who had reduction of visual acuity and bitemporal hemianopsia 2 years after 60Co-irradiation therapy (total 8000 rads) for Cushing's disease. CT scans showed low density in the pituitary fossa and irregular contrast-enhanced suprasellar mass, and metrizamide CT cisternography revealed the pituitary fossa filled with contrast medium. From those findings, secondary empty sella syndrome was suspicious. Case 2 was a 35-year-old male who had progressive visual disturbance 3 years after 60Co-irradiation therapy (total 9050 rads) for Cushing's disease. The right visual acuity was 0.05 and the left one was 0.1. Examination of visual field showed left homonymous hemianopsia. CT scans showed the contrast enhanced suprasellar mass extending to the right anterior thalamic region, and metrizamide CT cisternography detected secondary empty sella as same as that of Case 1. Both cases were treated by administration of steroid hormone intrathecally and orally which was not effective. Right frontotemporal craniotomies were performed. Intraoperative findings of the chiasmatic region revealed diffuse adhesions and thickening of arachnoid membrane with mesh-work of fine vascular proliferations and adhesiotomies were performed in both cases. On the postoperative course, visual disturbance did not improved in both cases. Histological examinations of the thicked arachnoids obtained intraoperatively showed the fibrous connective tissues with round cells infiltrations in both cases, and in Case 2, the small vessel in the arachnoid was occluded by organized thrombi. Authors reviewed and analyzed literatures of delayed radiation necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Computed tomographic demonstration of the effect of proximal parent artery ligation for giant intracranial aneurysms.

Four patients with giant intracranial aneurysms, which measured over 2.5 cm in diameter, were treated by ligation of the proximal parent artery. The location of the aneurysms were intracavernous in two patients, paraophthalmic in one patient, and vertebral in the other patient. The effect of ligation was followed by repeated computed tomography scans with angiographic correlation. The aneurysms thrombosed soon after ligation, and with time, gradually organized with a reversal of the mass effect. Five years after the ligation, one aneurysm thrombosed completely and lost its mass effect upon the adjacent structures. For giant aneurysms treated with ligation of the proximal parent artery, computed tomography scans are a useful method for continuing review, producing precise information concerning actual size, thrombus formation, and various pathological changes.

Adult↗
PubMed1983

Mutagenicity in Salmonella typhimurium TA98 of the serum extract of the organic matter derived from airborne particulates.

To investigate the interactions between mutagens and serum components, the mutagenicity of the serum extract of the organic matter derived from airborne particulates (tar) was examined by the Salmonella/mammalian microsome mutagenicity test. The mutagens in the organic matter were found to be extracted with serum but not with saline. The mutagenic activity of the serum extract of the tar, however, decreased to about 60% compared with that of the DMSO extract, when they were activated by S9 mix. On the other hand, without S9 mix, the mutagenic activities of the serum and DMSO extracts were about the same. Gel filtration of the serum extract was carried out and followed by mutagenicity testing of each fraction. It is suggested that the mutagens, which require metabolic activation, combine mainly with beta-lipoproteins and the direct mutagens with both alpha- and beta-lipoproteins in serum.

Air Pollutants↗
PubMed1983

Identification of a mutagenic substance, in Rubia tinctorum L. (madder) root, as lucidin.

Mutagenicity of the extract from Rubia tinctorum L. (madder) root was demonstrated on Salmonella typhimurium TA100 and TA98. The active substance wa purified and characterized by TLC, UV spectrum, IR spectrum, mass spectrum and [1H]NMR spectrum. All the mutagenic activity of the extract from the root of Rubia tinctorum L. was due to lucidin (1,3-dihydroxy,2-hydroxymethyl-9, 10-anthraquinone).

Anthraquinones↗