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Biomedical subjects

T Noguchi

Publications and source records attributed to T Noguchi.

At least 919 records · Page 51Linked to original sources

[Multiple gastric carcinoma with a coexisting gastric carcinoid--report of a case].

A 54-year-old man was operated on for multiple gastric carcinoma. A carcinoid tumor was found within Borrmann 3 type adenocarcinoma (well-differentiated) through examination of the resected stomach. Another carcinoma was II c type, moderately differentiated. The carcinoid seemed to be so-called submucosal tumor on the cut surface. Histologically, the carcinoid showed a less-differentiated trabecular arrangement, which was classified as the Soga D type. Argyrophilic reaction was positive (Grimelius) and argentaffin negative (Masson-Fontana). Secretory granules were seen by electron microscopy. Carcinoid syndrome was absent, and postoperative assays of 5-HT and 5-HIAA were within normal range.

Adenocarcinoma↗

Developmental profiles and properties of hepatic peroxisomal apo- and mitochondrial holoalanine:glyoxylate aminotransferase during chick embryogenesis.

Alanine:glyoxylate aminotransferase was present as the apoenzyme in the peroxisomes and as the holoenzyme in the mitochondria in chick embryos. The peroxisomal enzyme predominated in the early stage and gradually decreased during embryonic development and disappeared after hatching. In contrast, the mitochondrial enzyme gradually increased and predominated in the later stage of chick embryos. Peroxisomal alanine:glyoxylate aminotransferase in chick embryos was a single peptide with a molecular weight of about 40,000. The enzyme differed from the mitochondrial enzyme in the embryos, and mammalian alanine:glyoxylate aminotransferases 1 (with a molecular weight of about 80,000 with two identical subunits) and 2 (with a molecular weight of about 200,000 with four identical subunits) in molecular weights and immunological properties. Mitochondrial alanine:glyoxylate aminotransferase in chick embryos had an identical molecular weight and immunologically cross-reacted with mammalian mitochondrial alanine:glyoxylate aminotransferase 2. Pyridoxal 5'-phosphate dissociated easily from the peroxisomal enzyme saturated with pyridoxal 5'-phosphate. Hepatic aspartate:2-oxoglutarate aminotransferase and alanine:2-oxoglutarate aminotransferase in chick embryos, and hepatic alanine:glyoxylate aminotransferases in different animal species were all present as the holoenzyme.

Alanine Transaminase↗

Cell-free synthesis of ornithine decarboxylase. Changes in mRNA activity in the liver of thioacetamide-treated rats.

Ornithine decarboxylase (ODC)mRNA associated with free polysomes of rat liver was translated in a reticulocyte lysate cell-free system. Newly synthesized ODC protein was identified by specific immunoprecipitation, molecular size as determined by polyacrylamide gel electrophoresis with sodium dodecyl sulfate, and competition by excess unlabeled ODC in the immunoprecipitation. A single injection of thioacetamide was found to cause several fold increases in both immunotitratable ODC protein and polysomal ODC-mRNA activity, while it provoked a much larger increase in ODC activity in rat liver. The results indicate that the induction of hepatic ODC activity by thioacetamide treatment is due not only to an increase in the activity of polysomal ODC-mRNA but also to a translational and/or posttranslational control.

Acetamides↗

Molecular cloning of cDNA sequences for rat M2-type pyruvate kinase and regulation of its mRNA.

Rat M2-type pyruvate kinase mRNA was enriched from total polysomes isolated from AH-130 Yoshida ascites hepatoma cells, which contain a very high concentration of the M2-type enzyme, by immunoprecipitation with a specific antibody and Staphylococcus aureus cells. Double-stranded cDNA synthesized from the enriched mRNA was inserted into the PstI site of pBR322, and the resultant recombinant DNA molecules were used to transform Escherichia coli. Three clones containing DNA complementary to M2-type pyruvate kinase mRNA were identified by colony hybridization, hybrid-arrested translation, and hybrid-selected translation. A partial restriction map was constructed covering about 1.44 kilobase pairs. The cloned region of the M2-type mRNA showed a high degree of sequence homology with the M1-type mRNA and some homology with the L-type mRNA as determined by dot blot hybridization. The molecular size of the M2-type mRNA, which was estimated to be 2.35-2.65 kilobases on denaturing gel, was the same as that of the M1-type mRNA. The level of hepatic M2-type pyruvate kinase mRNA measured by hybridization assay using cloned cDNA as a probe was increased 2.5-fold 1 day and 3.9-fold 2 days after partial hepatectomy and then started to decrease. This induction was followed by similar changes in the enzyme activity. AH-130 hepatoma cells contained 100-150 times more M2-type isozyme mRNA than regenerating liver. These results suggest that the increased levels of M2-type isozyme in regenerating liver and hepatoma cells are primarily due to elevation of hybridizable M2-type mRNA concentration.

Animals↗

The effect of vitamin B6 deficiency on alanine: glyoxylate aminotransferase isoenzymes in rat liver.

Endogenous synthesis of oxalate has been reported to increase in vitamin B6 deficiency probably due to defective transamination of glyoxylate, the direct source of oxalate, to glycine. Alanine:glyoxylate aminotransferase (AGT) in the liver catalyzes most of the glyoxylate transamination in mammalian tissues (E. V. Rowsell, K. Snell, J. A. Carnie, and K. V. Rowsell (1972) Biochem. J. 127, 155-165). The effects of vitamin B6 deficiency on hepatic AGT isoenzymes, designated AGT 1 and AGT 2, respectively, were examined with male rats; AGT 1 is located both in the peroxisomes and in the mitochondria, and AGT 2 only in the mitochondria. The holo activity of combined peroxisomal and mitochondrial AGT 1 with a low Km for L-alanine rapidly decreased after a lag time of about 2 days during feeding of the vitamin B6-deficient diet (by 50% in 5 days, by 86% in 14 days). Peroxisomal AGT 1 activity was more affected than the mitochondrial. The holo activity of AGT 2 with a high Km for L-alanine decreased more slowly than AGT 1 (by 33% in 14 days, by 60% in 28 days). Urinary excretion of oxalate began to increase in 8-9 days, when AGT 2 remained intact but most of AGT 1 is depleted. When the defect in the glyoxylate transamination in vivo in vitamin B6 deficiency is considered, these findings suggest that it is due to the deficiency of AGT 1. The importance of peroxisomal AGT 1 is discussed, since peroxisomes have been described to be probably the major site of glyoxylate formation.

Alanine Transaminase↗

Stimulation of Snell dwarf mouse neuronal growth by GH and T4.

An investigation of the Snell dwarf motor cortex, area 6 of Caviness, was carried out by means of a modified Golgi silver impregnation method. The pyramidal neurons located in layer V were found to have small perikarya, short primary dendrites with sparse branchings. Following administration of bovine growth hormone (bGH) and thyroxine (T4) during the first 20 d of postnatal life, this retarded neuronal growth was restored to normal: neuronal perikarya were enlarged, and the dentrites were thicker with denser branchings. These results were confirmed in the sections stained for neuron specific enolase (NSE). These findings demonstrate that exogenous GH and T4, will enhance neuronal growth in the Snell dwarf cerebrum, and restore neuronal arborization to normal.

Animals↗

Occurrence of tetrodotoxin in the gastropod mollusk Tutufa lissostoma (frog shell).

Paralytic toxicity was detected in gastropod mollusk Tutufa lissostoma (frog shell) specimens collected from Suruga Bay, Shizuoka Prefecture, Japan. Seventeen of the 22 digestive glands removed were toxic; the highest toxicity, expressed as tetrodotoxin (TTX), being as high as 700 mouse units (MU) per gram. Attempts were made to isolate the toxin from pooled digestive glands by activated charcoal treatment and column chromatography on Amberlite IRC-50, CM-Sephadex C-25 and Bio-Rex 70. The toxin showed a specific toxicity (as TTX) of 4200 MU/mg. It exhibited the same thin-layer chromatographic and electrophoretic behaviors and 1H-NMR spectrum as TTX. The toxin gave the same pattern as the TTX standard when alkali-hydrolyzed and analyzed by GC--MS, indicating that it contains the quinazoline skeleton specific to TTX. From these results the frog shell toxin was identified as TTX.

Animals↗

A tetrodotoxin-like substance as a minor toxin in the xanthid crab Atergatis floridus.

Toxins were extracted from the xanthid crab Atergatis floridus inhabiting Ishigaki Island, Okinawa, and subjected to several types of chromatography, resulting in separation into gonyautoxin and saxitoxin fractions. Thin-layer chromatographic and electrophoretic analyses showed that the gonyautoxin fraction was composed of gonyautoxins 1-4, along with some unknown compounds. Gas chromatography-mass spectrometry demonstrated that the gonyautoxin fraction gave rise to the C9-base when alkali-hydrolyzed, indicating that this fraction contained a tetrodotoxin-like compound possessing the quinazoline skeleton specific to tetrodotoxin. The saxitoxin fraction consisted of neosaxitoxin, saxitoxin and two unknown compounds.

Animals↗

Enzymatic and immunological comparison of alanine: glyoxylate aminotransferases from different fish and mammalian livers.

Alanine:glyoxylate aminotransferase was highly purified and characterized from mackerel liver. The purified enzyme had a mol. wt of approx. 200,000 with four identical subunits. It was specific for L-alanine and L-serine with glyoxylate and for L-serine with pyruvate as amino acceptor. The mackerel enzyme was similar to partially purified alanine:glyoxylate aminotransferases from other fish (sardine, gopher gray rock cod and yellow mackerel) liver with respect to mol. wts and substrate specificity. These fish enzymes were similar to mammalian liver alanine:glyoxylate aminotransferases 1 in substrate specificity and to mammalian alanine:glyoxylate aminotransferases 2 in mol. wts. An immunological cross-reactivity of hepatic alanine:glyoxylate aminotransferase was observed between mackerel and other fishes but not between mackerel and mammals.

Alanine Transaminase↗

Rapid regulation of L-type pyruvate kinase mRNA by fructose in diabetic rat liver.

The effect of fructose on the induction of L-type pyruvate kinase mRNA in diabetic rat liver was studied by using a cloned cDNA probe. Fructose feeding resulted in a 5- to 6-fold increase in the L-type enzyme mRNA level after 1 to 3 days. These changes were approximately proportional to the changes in the level of translatable mRNA of this enzyme. A significant increase in total cellular L-type enzyme mRNA level was observed within 2 h after fructose feeding and the level reached a maximum after 8 h. Dietary glycerol also markedly increased the L-type mRNA level. These alterations were essentially due to the changes in the cytosolic mRNA. Northern blot analysis of total cellular RNA revealed that two L-type enzyme mRNA species with molecular sizes of 2.1 and 3.6 kilobases were proportionally increased during the fructose induction. The two mRNA forms were found in immunopurified L-type enzyme mRNA and directed synthesis of the L-type subunit in vitro; they are therefore functional mature forms. In contrast, analysis of nuclear RNA showed five putative precursor RNA species for the enzyme, up to 9.4 kilobases in length, in the liver of fructose-fed rats, while no band of the RNA species was found in the nuclei of control liver. The changes in the number of bands of these RNA species and their intensities after fructose feeding preceded the changes in the level of total cellular L-type enzyme mRNA sequences. These results indicate that dietary fructose causes a rapid increase in the level of L-type pyruvate kinase mRNA sequences by acting at the nuclear level.

Animals↗

Hypomyelination in the cerebrum of the congenitally hypothyroid mouse (hyt).

2',3'-Cyclic nucleotide 3'-phosphohydrolase activity in the cerebrum of the inherited primary hypothyroid mouse (hyt/hyt) is reduced in comparison with the normal heterozygate (hyt/+). No differences were observed with regard to DNA and RNA content and the RNA/DNA ratio. The results of this study indicate that hypomyelination in the hypothyroid mouse is restricted to the cerebrum, and is not related to arrested glial proliferation.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

Pharmacokinetics of cefpiramide (SM-1652) in humans.

The pharmacokinetics of cefpiramide (SM-1652) were studied after the intravenous administration of single or multiple doses to 21 healthy volunteers. The cefpiramide concentration in plasma at time zero after a bolus intravenous injection of 500 or 1,000 mg was 152 or 303 micrograms/ml, respectively. The maximum cefpiramide level in plasma at the end of a 1-h infusion of 1,000 or 2,000 mg was 166 or 317 micrograms/ml, respectively. The mean plasma half-life of cefpiramide in 15 subjects who received a single dose of 500 or 1,000 mg was 4.44 h. There was no evidence of drug accumulation in plasma when 500 or 1,000 mg of cefpiramide was administered 11 times at 12-h intervals. Urinary excretion of cefpiramide over a 24-h period was ca. 22.5%, regardless of the intravenous administration technique and the dosage. Fecal recoveries of cefpiramide varied from 0 to 36.9% in different subjects.

Adult↗