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Biomedical subjects

T Nagata

Publications and source records attributed to T Nagata.

At least 541 records · Page 30Linked to original sources
PubMed1986

[Distribution pattern of fibronectin in human lung cancer tissue].

The distribution pattern of fibronectin in human lung cancer tissues has been studied using the indirect immunoperoxidase technique. In adenocarcinoma fibronectin is observed in the basal side of cancer cells and tumor stroma. In squamous cell carcinoma, it is seen in the basal side of cancer cells, surface of cancer cells and tumor stroma. The difference between adenocarcinoma and squamous cell carcinoma in invasion and metastasis was investigated to have some relation to the distribution pattern of fibronectin.

Adenocarcinoma↗
PubMed1985

Developmental microvascular architecture of the rat cerebellar cortex.

External and internal microvascular architectures of the developing rat cerebellar cortex, from embryonic day 18 to postnatal day 14 and in adults, were studied using a cerebrovascular casting method for scanning electron-microscopic observation. The external vascularization of the developing cerebellum showed the most significant alteration in vascular morphology at the stage of intensive proliferation of matrix cells in the external granular layer (EGL) from birth to postnatal day 4. It consisted of multiple luminal protrusion of the vessels, septum formation in the lumina, and small, ring-like anastomoses. Moreover, at the end of this stage, these structures of the vessels disappeared and the subarachnoid space was filled with newly-formed microvascular networks. Thereafter, architectural change of the developing pial vessels was mainly accomplished by elongation of each contorted vessel of the network. Concerning internal vascularization, a few vessels connected with the pial vessels were observed in the cerebellar plate forming a loose, simple network in the deeper neural parenchyma before the stage of foliation began. During the period of thickening of the EGL, however, there was no alteration in vascularity of the parenchyma other than the architectural changes proportionate to the newly-formed folia. It was during the synaptogenetic stage in the internal granular layer that the earliest intraneural vascular plexuses were formed. The vascular network in the molecular layer was formed after disappearance of the EGL. These findings suggest that vascular proliferation correlated with EGL-formation pertains to the pial vessels, and not the intraneural ones, which develop after neuronal cell migration in the developing cerebellum has taken place.

Animals↗
PubMed1985

DNA content of hepatocytes in various stages of liver cirrhosis.

In order to search for some parameters that would make it possible to predict a potentially high risk of evolution from liver cirrhosis to hepatocellular carcinoma (HCC), the DNA content of hepatocytes in patients with liver cirrhosis with or without development to HCC was investigated by means of microspectrophotometry in Feulgen-stained specimens. In patients without development of HCC in more than 5 years of follow-up, 90% or more of tested hepatocytes were diploid, whereas in patients with liver cirrhosis who developed HCC within 3 years the frequency histogram of nuclear DNA content was widely spread from diploid to hyperpolyploid with a small peak of triploid. Furthermore, in the latter group of patients, many of the binucleate cells had different DNA contents in each paired nucleus. In non-cancerous portions of HCC, the ploidy histogram of nuclear DNA content was widely spread from diploid to polyploid with different DNA contents of each paired nucleus in binucleate cells, without the small peak of triploid. These results suggest that the deranged cell kinetics of hepatocytes in cirrhosis may be considered to be a state of potentially high risk for the evolution of HCC, and that a patient with liver cirrhosis with such an abnormal hepatocyte DNA content should be followed up carefully for the early diagnosis of HCC.

Adult↗
PubMed1985

Novel dnaG mutation in a dnaP mutant of Escherichia coli.

Reexamination of the dnaP18 mutant strain of Escherichia coli revealed that the mutation responsible for the arrest of DNA replication and cell growth at high temperatures resides in the dnaG gene rather than in the dnaP locus as previously thought; this mutation has been designated dnaG2903.

Bacterial Proteins↗
PubMed1985

Vector mosquitoes of Wuchereria bancrofti at Bicol region in the Philippines. 1. Transmission capability.

Mosquitoes were surveyed for the capability of filaria transmission at Sitio Bacolod and Barrio Salvacion, in Bicol region, Luzon, Philippines. The results of indoor collections and experimental infections showed that the infective rates and the median density of infective larvae per infected mosquito were significantly higher in Aedes poicilius than in Culex quinquefasciatus. Aedes poicilius was found to be the principal vector of bancroftian filariasis in this region.

Aedes↗
PubMed1985

The localization of a new antithrombotic agent, cilostazol, in CHO-K1 cells as demonstrated by autoradiography.

Cilostazol (6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydro-2(1H)- qui nolinone, OPC-13013), a new antithrombotic agent, has a potent inhibitory action on platelet aggregation. The cellular and subcellular distribution of this compound was investigated. Autoradiographic studies using tritiated cilostazol showed that this compound penetrates the cell membrane of Chinese hamster ovary cells, clone K1 (CHO-K1 cells) and is distributed mainly in the cytoplasma. These results suggest that this compound exhibits its pharmacological action through specific inhibition of cytoplasmic cyclic AMP phosphodiesterase.

Animals↗
PubMed1984

The visual field representation of the rat ventral lateral geniculate nucleus.

The representation of the visual field in the ventral lateral geniculate nucleus (LGNv) was studied in rats anesthetized with urethane by recording the response of single units to visual stimulation. Receptive fields of LGNv units were plotted on a campimeter, 60 cm in diameter, which was placed 30 cm from the contralateral eye. LGNv neurons responded mainly to stimulation of the contralateral eye with on-tonic characteristics. Few neurons responded only to stimulation of the ipsilateral eye and no binocular interaction was observed. Retinotopic organization was clearly seen in the LGNv; the nasal visual fields were represented dorsally, the temporal fields ventrally, and the upper to lower visual fields were in the rostrolateral to caudomedial parts of the LGNv. A given point in the visual field is represented along a line running through the LGNv in a rostrocaudal direction. Almost the entire horizontal extent of the contralateral visual field was represented in the LGNv, whereas vertically the visual field between 40 degrees above and 20 degrees below the distribution axis was represented. The major axis of the strip of the visual field containing all the RF centers, which is referred to as the distribution axis, inclined nasally up and temporally down at an angle of 10.4 degrees to the 0 degree horizontal meridian line. The representation of the distribution axis in the retina was in accordance with the major axis of retinal ganglion cell distribution (Fukuda, '77; Schober and Gruschka, '77).

Animals↗
PubMed1984

Phase I study of 7-N-(p-hydroxyphenyl)-mitomycin C.

The Phase I study of N-7-(p-hydroxyphenyl)-mitomycin C (KW 2083, M 83) was performed. The dose-limiting toxicity was leukopenia and thrombocytopenia and a maximum tolerable dose was 70 mg/m2. Nonhematologic toxicities included nausea (44%), vomiting (13%), diarrhea (2.7%), azotemia (8.1%), proteinuria (5.4%), alopecia (8.1%) and elevated hepatic enzymes (2.7%). This Phase I study indicates that the recommended starting dose for Phase II studies for patients without significant myelosuppression would be 50 mg/m2 at 6 week intervals in an intravenous push. KW 2083 should be avoided in patients with impaired renal functions and proteinuria because of permanent renal damages caused by the drug.

Aged↗
PubMed1984

Electron microscopic demonstration of phospholipase B activity in the liver and the kidney of the mouse.

A method has been developed for electron microscopic histochemical demonstration of phospholipase B, (lecithinase B, E C 3.1.1.5, lysolecithin acyl hydrolase), which hydrolyzes alpha- and beta-positions of phospholipids in mouse liver, kidney and adrenal tissues. Tissues either fixed in cold 1% paraformaldehyde or unfixed were cut into 40 micrometers frozen sections and were incubated at 37 degrees C in a medium at pH 6.6 or 4.5 containing 2 microM lysolecithin and 0.25 mM CaCl2 for 20 min. The fatty acids liberated by enzymatic hydrolysis were trapped as calcium precipitate and were converted to lead precipitate by treatment with lead nitrate. The reaction products were observed by electron microscopy to be localized on the end of the smooth endoplasmic reticulum at pH 6.6 and in lysosomes and lipid droplets at pH 4.5. It is concluded that the products showed the localization of phospholipase B activity.

Animals↗
PubMed1984

Structural analysis of the dnaA and dnaN genes of Escherichia coli.

The nucleotide sequence of the entire region containing the Escherichia coli dnaA and dnaN genes was determined. Base substitutions by such mutations as dnaA46, dnaA167, dnaN59, and dnaN806 were also identified. Analyses of coding frames, the mutational base substitutions, and other data indicate that dnaN follows dnaA, both have the same orientation, and are separated by only 4 bp. The deduced amino acid sequence specifies Mrs and isoelectric points consistent with those of the previously identified gene products. The transcriptional initiation site of the dnaA gene was assigned by analysis of in vitro RNA products. Examination of the intercistronic sequence and analysis of in vitro transcription supported the notion that the dnaA and dnaN genes constitute a single operon.

Amino Acid Sequence↗