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Biomedical subjects

T Nagata

Publications and source records attributed to T Nagata.

At least 469 records · Page 26Linked to original sources
PubMed1990

Study of RNA synthesis in the livers of aging mice by means of electron microscopic radioautography.

The application of 3H-uridine radioautography results in labeling of the liver cells in which RNA is synthesized at various ages of the mouse. Quantitative changes of RNA synthesis in the hepatocytes of aging mice were studied by electron microscopic radioautography. The silver grains were mainly located in the nucleoli and nuclei and a few in the mitochondria and rough surfaced endoplasmic reticulum of almost all of the cell populations at various ages. The number of silver grains in the hepatocyte gradually increased after birth, reached the maximum at 14 days of postnatal age, then decreased to 24 months with aging. The number of silver grains of the euchromatin was more than those of the heterochromatin of the hepatocyte nuclei at various ages. The number of silver grains of the granular components was more than those of the fibrillar components of the hepatocyte nucleoli at various ages. However, the ratio of silver grains among euchromatin, heterochromatin, granular components and fibrillar components remained approximately constant.

Aging↗
PubMed1990

[Clinical investigation of urinary dipeptidyl aminopeptidase IV (DAP IV) activity in patients with primary glomerular diseases].

To assess the role of urinary dipeptidyl aminopeptidase IV (DAP IV) in glomerular diseases, we measured urinary levels of DAP IV in 55 patients with chronic glomerulonephritis (CGN), 41 patients with nephrotic syndrome (NS), 21 patients with chronic renal failure (CRF) and 48 normal controls. The urinary DAP IV levels in patients with CGN were significantly higher than those in normal controls and were higher in patients with more active disease. The frequency of normal urinary DAP IV levels in patients with CGN was significantly lower than that of normal urinary N-acetyl-beta-D-glucosaminidase (NAG) levels in those with CGN. The urinary DAP IV levels in patients with NS were the highest among the 3 patient groups. The urinary DAP IV/g.protein ratio was significantly lower in the patients with minimal change nephrotic syndrome than in those with membranous glomerulonephritis or membranoproliferative glomerulonephritis. In both patients with CGN and those with NS, urinary DAP IV levels correlated significantly with the amounts of urinary protein and the urinary NAG levels. The urinary DAP IV levels in patients with CRF were lower than those in patients with CGN and NS who had normal GFR, and there was a significant negative correlation between the urinary DAP IV levels and the serum creatinine levels. We conclude that the measurement of urinary DAP IV is useful for detecting or monitoring glomerular disease.

Adolescent↗
PubMed1990

Demonstration of ingested thinner.

Taking a practical forensic case that provided an opportunity, an attempt was made to prove that paint thinner had been ingested by the victim. One ml of standard thinner solution, which was prepared by mixing toluene, ethyl acetate, and isobutanol, was given by gavage to rats, after which, on sacrifice of the animals, the distribution of thinner components in the body tissue and in the gastric contents was examined by gas chromatography, using the salting-out technique and the headspace method. Three thinner components and ethanol, a metabolite of ethyl acetate, were found to be present in the gastric contents, whereas only toluene was found in the blood and in the other tissue. From these results we thus have concluded that paint thinner taken can be proved by detecting the presence of ethyl acetate and isobutanol together with toluene in the stomach, whereas only toluene can be detected in the body fluids and the other tissue.

Acetates↗
PubMed1990

[Neurobehavior and mental development of newborn infants delivered under epidural analgesia with bupivacaine].

The neurobehavior of newborn infants delivered under epidural analgesia with bupivacaine was analyzed by Amiel-Tison's Neurological and Adaptive Capacity Score (NACS), while Tsumori-Image's questionnaire assessed the above infants' mental development. Seventy-two newborn infants under epidural analgesia (39 delivered spontaneously and 33 by vacuum extraction) and twenty-eight newborn infants without epidural analgesia as controls (15 delivered spontaneously and 13 by vacuum extraction) were under study. The following results were obtained 1) In the 24 hour period following childbirth, NACS tended to be low in relation to the total dosage of bupivacaine administered to the mother. 2) In the 24 hour period following childbirth and continuing until the 3rd day, NACS were relatively low regardless of the mode of delivery. 3) There was no significant difference between the neonatal physiological weight loss in newborn infants under epidural analgesia and those without epidural analgesia (controls). 4) Newborn infants under epidural analgesia displayed an average mental quotient at the first, third, and sixth month after childbirth. Although epidural analgesia with bupivacaine might lower the neurobehavior of newborn infants in the immediate postchildbirth period, the newborn infants should return to normal without any complications.

Anesthesia, Epidural↗
PubMed1990

Electron microscopic radioautographic studies on DNA synthesis in the hepatocytes of aging mice as observed by image analysis.

Quantitative changes of DNA synthesis in the hepatocytes of aging mice were studied by electron microscopic radioautography. Ultrastructural changes of labelled and unlabelled hepatocytes were estimated quantitatively by the image analysis. The results revealed that at various ages, the area of the cytoplasm and nuclei of labelled hepatocytes were more than those of the unlabelled cells. No significant changes were observed in the nucleoli. The area of the endoplasmic reticulum and mitochondria were less in the labelled hepatocytes than in the unlabelled hepatocytes. The number of the mitochondria was less in the labelled hepatocytes than in the unlabelled hepatocytes. The cell organelles of the hepatocytes that were synthesizing DNA were not well developed, as compared to those not synthesizing DNA during the postnatal development.

Aging↗
PubMed1990

Encephalitis induced by a canine distemper virus in squirrel monkeys.

Intracerebral inoculation with canine distemper virus (CDV) caused acute neurological signs of viral encephalitis in squirrel monkeys. Electroencephalogram revealed an abnormal sharp wave and seizure discharges resembling those of epilepsy. There was parenchymal inflammation, perivascular cuffs, neuronal degeneration, and glial reactions. Virus antigen was detected immunohistologically in the neurons and ependymal cells. Thus, CDV infection in squirrel monkeys provides an animal model for viral encephalitis and epilepsy.

Acute Disease↗
PubMed1990

Sulfide concentrations in postmortem mammalian tissues.

Postmortem changes in sulfide concentrations in body tissues were examined in autopsied rats exposed to hydrogen sulfide concentrations of 550 to 650 ppm, and in nonexposed rats and humans. Analyses were made by gas chromatography, following an extractive alkylation. Sulfide concentrations in the blood, liver, and kidneys of rats increased in both the exposed and nonexposed groups, depending on the lapse of time after death. On the other hand, the lung, brain, and muscle showed little or no change in sulfide concentration with elapse of time after death. The data obtained from human tissues were almost the same as those for rats, except data for blood, in which no or little increase of sulfide was observed.

Animals↗
PubMed1989

Sulphation of secreted phosphoprotein I (SPPI, osteopontin) is associated with mineralized tissue formation.

Secreted phosphoprotein I (SPPI) is a prominent structural protein in mineralized connective tissues. Rat bone cells in culture produce several forms of SPPI that differ in post-translational modifications such as phosphorylation and sulphation. To determine the significance of protein sulphation in bone formation, the synthesis of SPPI was studied in vitro using rat bone marrow cells (RBMC) which form bone-like tissue when grown in the presence of dexamethasone (Dex) and beta-glycerophosphate (beta-GP). In the presence of 10(-7) M Dex SPPI expression was stimulated 4-5-fold. Radiolabelling multilayered RBMCs for 48 h with [35S]-methionine, Na2[35SO4], or Na3[32PO4] revealed that two major phosphorylated forms of SPPI were secreted into the culture medium: a highly phosphorylated form migrating at 44 kDa on 15% SDS-PAGE and a less phosphorylated 55 kDa form. In the mineralized tissue formed in the presence of Dex and beta-GP, both forms of SPPI, in addition to proteoglycans and a 67 kDa protein, incorporated significant amounts of [35SO4]. Sulphation of SPPI was not observed in the absence of mineral formation, indicating that the sulphation of SPPI is closely associated with mineralization and that it can be used as a sensitive and specific marker for the osteoblastic phenotype.

Animals↗
PubMed1989

Molecular cloning and characterization of cDNA encoding mouse cytokeratin no. 19.

We have isolated cDNA clones encoding the mouse cytokeratin No. 19 (Ck 19) from an intestinal cDNA library using synthetic oligodeoxyribonucleotides as probes. We obtained four independent clones, which correspond to about 1.4-kb of ck19 cDNA. Nucleotide sequence analysis revealed that these cDNAs encode a protein of 44,541 Da composed of 403 amino acids (aa). The deduced aa sequence defines an alpha-helical central domain, and suggests that the protein lacks a C-terminal non-alpha-helical tail segment, characteristic of the human and bovine 40-kDa keratins (Ck19). The overall aa identity between mouse Ck19 and human and bovine Ck19 is very high, 82.7% and 82.4%, respectively. The coil-forming central domain of mouse Ck19 has 45-65% similarity to other type-I Ck polypeptides, while it displays only 20-30% similarity to type-II Ck polypeptides. Northern blot analysis showed that mouse ck19 mRNA is strongly expressed in adult intestine, stomach and uterus. Interestingly, it is expressed in a placental cell line and a retinoic acid-treated mouse teratocarcinoma cell line (F9), but not in a parietal yolk sac endoderm-like cell line (PYS-2). This pattern of expression is very similar to that for the mouse gene encoding extra-embryonic endodermal cytoskeletal protein C (EndoC), suggesting they may be the same.

Amino Acid Sequence↗
PubMed1989

Effects of kainic acid lesions in rat ventral lateral geniculate nucleus upon field potentials of the superior colliculus: correlation between morphological and physiological observations.

Morphological and physiological effects of kainic acid (KA) lesions in rat ventral lateral geniculate nucleus (LGV) were studied 1.5 and 6 h after KA injection. Morphological changes were examined mainly by electron micrographs. At 1.5 h after KA injection dendrites were dilated and some vacuolations occurred in both dendrites and perikarya including geniculotectal relay neurons while axons were completely intact and cell organelles almost remained intact. Six h after KA injection dendrites and cell bodies were massively dilated with degeneration of cell organelles accompanied by sparse cytoplasm and deformed chromatin in the nucleus. However, almost all presynaptic axons, mainly retinogeniculate fibers, still remained intact. The electron micrographs demonstrate that destruction occurred first in dendrites, next in cell bodies and finally axons were likely to be affected. These morphological changes induced by KA are compatible with physiological effects which were assessed by the field response of the superior colliculus (SC) evoked by stimulation of the optic chiasm. During 1.5-2 h after KA injection all components of the SC response, the presynaptic and postsynaptic negative-positive waves were enhanced. The enhancement of the SC response may be correlated with morphological changes in terms of excitatory action of KA resulting in facilitation of geniculotectal transmission. Six h after KA injection postsynaptic negative-positive waves gradually declined in amplitude while the presynaptic wave returned to control level. The late suppression of postsynaptic components of the SC response may be attributable to a marked loss of geniculotectal transmission resulting from destruction of geniculotectal relay neurons by KA.

Action Potentials↗
PubMed1989

Platelike and globelike inclusion bodies associated with rough endoplasmic reticulum in alveolar type 2 cells of the sheep.

We studied the ultrastructure of alveolar type 2 cells of sheep. The inclusion bodies of rodlike structures or cisternal bodies derived from the endoplasmic reticulum were found in 13.6 +/- 7.0% (+/- SD) of type 2 cells. The length of the rodlike structure varied, the longest being 2.4 microns; but the width was usually 0.1 micron. Rod-like structures were usually straight and arranged in parallel stacks. An electron-dense line ran longitudinally at the center of the rodlike structures. Serial ultrathin sections revealed that the rodlike structures did not seem to be three-dimensionally rod-shaped structures but were actually plate-disc or cup-shaped, and the piled-up rodlike structures were connected to each other at their ends. This rodlike structure in type 2 cells of sheep seems rather to be a platelike inclusion body. The cisternal body, on the other hand, was circular or oval-shaped cisternae containing aggregated electron-dense materials distributed in an arabesque or speckled pattern. Serial ultrathin section examination revealed the cisternal body to be three-dimensionally a globe. Some plate bodies were arranged near the cisternal body, suggesting the transformation from the latter to the former. The functional significance of these findings has not yet been elucidated.

Animals↗
PubMed1989

Effect of 15(R)-15-methyl PGE2 (arbaprostil) on duodenal bicarbonate secretion in rat.

The present study was designed to observe the effect of 15(R)-15-methyl PGE2 (arbaprostil) on duodenal bicarbonate secretion in male Wistar rats anesthetized with urethane. A proximal duodenal loop (1.5cm) was made and perfused with saline (pH4.5) in an air tight circle system. The pH and Pco2 of the perfusing fluid were measured continuously and the quantity of bicarbonate was calculated according to the Henderson-Hasselbalch equation. Vehicle or arbaprostil was injected intravenously as a bolus injection. The total output of bicarbonate in 30 min was as follows; control: 0.449 +/- 0.093 microEq (mean +/- SE); 1,10 and 100 mu/kg of arbaprostil: 0.752 +/- 0.218, 2.75 +/- 0.430 and 5.958 +/- 0.578 microEq respectively. Arbaprostil (10 and 100 micrograms/kg) increased the total output of bicarbonate significantly (p less than 0.001). The rate of secretion was also increased by arbaprostil.

Animals↗
PubMed1989

Complete ten-year postgastrectomy follow-up of early gastric cancer.

The postoperative courses of 109 patients with early gastric carcinoma treated from 1970 through 1976 were followed for 10 years. The cumulative 5-year survival rate was 96 percent and the 10-year survival rate was 92 percent. In this series, there was no significant difference in the survival rates between the mucosal cancer and submucosal invasion groups or between patients with and without lymph node metastasis. Five patients died from the recurrent cancer. The other causes of death were metachronous primary cancer in eight patients, synchronous primary cancer of sigmoid colon or rectum in two, cerebrovascular accident in six, heart disease in six, other causes in four, and unknown causes in four. Although the prognosis of early gastric cancer is remarkably good, patients should be carefully followed over a long period for late recurrence of the primary cancer and possible metachronous cancer of the other organs.

Adult↗
PubMed1989

Effects of extracellular calcium and sodium on cadmium uptake in guinea-pig and rabbit aorta.

1. Effects of Na+ and Ca2+ on Cd2+ uptake in the guinea-pig and rabbit aorta were investigated. 2. The Cd2+ fraction can be divided with EDTA and Zn2+. The EDTA fraction may be intracellular fraction and the Zn2+ fraction may be loosely bound to surface membrane. 3. In Na+ deficient solution the Zn2+ fraction was markedly increased and the EDTA fraction also increased while the external Ca2+ concentrations scarcely affect the Cd2+ contents in both fractions. 4. Cd2+ did not affect the cellular Na+ and K+ contents. 5. These results suggest that Na+ strongly relates with these fractions but Na+ pump does not contribute to these phenomena.

Animals↗
PubMed1989

A newly designed apparatus for testing blood levels of fuel vapor.

An apparatus for exposure of laboratory animals to fuel vapor was designed, manufactured and set up for routine experiments. Gasoline was vaporized by warming and was introduced into a series of chambers in which the concentration was regulated and stabilized, using air pumps. Concentration of the vapor in a chamber was controlled and experiments on rats showed a positive correlation between blood levels and vapor concentration at the time of exposure. A case of suicide by gasoline poisoning was briefly described.

Administration, Inhalation↗
PubMed1989

Effects of insulin and parathyroid hormone on DNA synthesis and ornithine decarboxylase activity in cultured bovine dental pulp.

The effects of insulin and parathyroid hormone (PTH) on the proliferation of developing bovine dental pulp in an explant culture system were studied. Dental pulp explants were cultured on siliconized lens paper floating on the serum-free medium for up to 72 h. Ornithine decarboxylase (ODC) activity increased and reached a peak after 24 h. DNA synthesis increased continuously after a lag period of 24 h. Insulin (10 milliunits per ml) stimulated ODC activity 1.3-fold and DNA synthesis 1.5-fold. PTH alone (1 unit per ml) stimulated ODC activity in 1.7-fold, but did not affect DNA synthesis. PTH plus insulin caused greater increases in ODC activity and DNA synthesis in dental pulp explants than insulin alone (ODC, 2.6-fold; DNA, 3.7-fold). These results suggest that insulin and PTH are involved in the regulation of growth of dentinogenically active bovine dental pulp.

Animals↗