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Biomedical subjects

T Noguchi

Publications and source records attributed to T Noguchi.

At least 613 records · Page 34Linked to original sources
PubMed1991

A tryptic peptide from beta-casein depresses protein synthesis and degradation and enhances ureogenesis in primary cultures of rat hepatocytes.

1. A peptide which enhances ureogenesis in primary cultured hepatocytes of rats was isolated from a tryptic digest of bovine beta-casein. 2. The structure of the peptide was Ala-Val-Pro-Tyr-Pro-Gln-Arg which is located from 177th to 183rd residues from N-terminal of beta-casein. 3. The peptide also showed the activity to inhibit protein synthesis and protein degradation. 4. It also inhibited DNA synthesis of hepatocytes induced by insulin and/or epidermal growth factor.

Amino Acid Sequence↗
PubMed1991

Tetrodonic acid-like substance; a possible precursor of tetrodotoxin.

A tetrodonic acid-like substance which was hardly distinguishable from authentic tetrodonic acid in thin-layer chromatography, high performance liquid chromatography, etc., was successfully purified from the ribbon worm and flatworm by a method consisting mainly of Bio-Gel P-2 column chromatography. The tetrodonic acid-like substance showed a specific toxicity of approximately 700 mouse units/mg as tetrodotoxin, unlike tetrodonic acid which is a completely non-toxic substance. Instrumental analyses including gas chromatography-mass spectrometry, secondary ion mass spectrometry and thin-layer chromatography/fast atom bombardment mass spectrometry disclosed that the tetrodonic acid-like substance had a structure similar to, but not the same as, that of tetrodotoxin. This, along with its high convertibility into tetrodotoxin during storage and other experimental operations, suggested that the tetrodonic acid-like substance is a precursor of tetrodotoxin.

Animals↗
PubMed1991

Vitamin D3 stimulates the production of prostacyclin by vascular smooth muscle cells.

The effects of vitamin D3 on the production of prostacyclin (PGI2) by cultured rabbit vascular smooth muscle cells (VSMCs) were investigated. PGI2 synthesis by VSMCs was significantly increased in the presence of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 1 alpha hydroxyvitamin D3 (1 alpha(OH)D3) at 48 hours [1,25(OH)2D3 greater than 1 alpha(OH)D3]. Physiological concentration of 1,25(OH)2D3 (10(-10) M) significantly increased the synthesis of PGI2. Further, we observed that treatment with 1,25(OH)2D3 significantly induced the activity of cyclooxygenase without changing the activity of phospholipase A2. These findings suggest that the mechanism of action of 1,25(OH)2D3 on the synthesis of PGI2 is mediated by the cyclooxygenase pathway. It seems possible that vitamin D3 is a vasoactive agent and may play a protective role in the development of atherosclerosis.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Haloperidol reductase activity in red blood cells from oriental patients on haloperidol.

1. We measured haloperidol reductase activity in red blood cells in 87 samples collected from 50 Japanese psychiatric patients on HAL. HAL reductase activities in the patients were in a range of 7.9-26.1 pmol/hr/10(6) RBC (mean = 13.4, S.D. = 3.4). Interindividual variability was as large as 25.4% (CVs), while intraindividual CVs were small (8.9%). 2. Distribution of HAL reductase activities was normal but their values were slightly lower in the patients than those in the normal controls, though the difference between these two groups was not significant. 3. No significant correlations were found between HAL reductase activity in RBC vs dose of HAL per body weight, or plasma and RBC RHAL/HAL ratio.

Adolescent↗
PubMed1991

Effects of aldose reductase inhibitors on prostacyclin (PGI2) synthesis by aortic rings from rats with streptozotocin-induced diabetes.

The effects of aldose reductase inhibitors (ARIs) on the synthesis of prostacyclin (PGI2) by aortic rings from diabetic rats were examined. The ARIs studied were ONO-2235 and isoliquiritigenin, a new compound extracted from glycyrrhizae radix. The content of sorbitol in the sciatic nerve of diabetic rats induced by streptozotocin was significantly increased as compared with that of controls. This increase was significantly inhibited by the administration of an ARI. On the other hand, there was a marked decrease in the synthesis of PGI2 by the diabetic rats compared with the control rats. The decrease in PGI2 synthesis was significantly reversed by the administration of an ARI. Furthermore, the synthesis of PGI2 by the aortic rings was inversely correlated with the content of sorbitol in sciatic nerves. Those observations suggest that an ARI may have a beneficial effect on the vascular synthesis of PGI2 in diabetes mellitus.

Aldehyde Reductase↗
PubMed1991

Vibrational spectroscopy of excited electronic states in carotenoids in vivo. Picosecond time-resolved resonance Raman scattering.

The vibrational spectroscopy and population dynamics of excited singlet (2(1)Ag), excited triplet (3B u), and the ground (1Ag) electronic states of carotenoids in chromatophores of Chromatium vinosum (mainly spirilloxanthin and rhodopin) and of the same carotenoids in benzene solutions are examined by picosecond time-resolved resonance Raman scattering. Coherent Stokes Raman scattering from the ground states of carotenoids in chromatophores also is observed. Resonance Raman spectra of in vitro rhodopin and spirilloxanthin when compared with in vivo data demonstrate that scattering from spirilloxanthin dominates the in vivo spectrum. Comparisons of the time-dependent intensities of 2(1)Ag and 1Ag resonance Raman bands from both in vitro and in vivo carotenoids suggest that vibrationally excited levels in 1Ag are populated directly by the decay of the 2(1)Ag state and that these levels relax into a thermalized distribution in less than 50 ps. The appearance of asymmetrically broadened, ground-state resonance Raman bands supports this conclusion. Formation of the 3Bu state is observed for carotenoids in chromatophores, but not for in vitro spirilloxanthin indicating that the 3Bu state is formed by fission processes originating from the spatial organization of pigments within chromatophores. The rate at which the intensities of 2(1)Ag resonance Raman bands decay is faster for the carotenoids in vivo than for those in vitro thereby indicating that additional relaxation channels (e.g., energy transfer to bacteriochlorophylls) are present in the chromatophore. The similarity of the in vivo and in vitro 2(1)Ag resonance Raman spectra shows that no significant modifications in the vibronic coupling has been caused by the chromatophore environment.

Bacterial Chromatophores↗
PubMed1991

Effect of protein deprivation on insulin-like growth factor-binding proteins in rats.

The effect of protein deprivation on plasma concentration of insulin-like growth factor-binding proteins (IGFBP) was studied in rats. A significant decrease in the concentration of IGFBP of molecular weight (mass) approximately 40 kDa was observed in protein-deprived rats. There was no prominent effect of protein deprivation on the concentration of IGFBP with molecular weights of about 30 kDa or 22-24 kDa. The binding capacity to plasma IGFBP of exogenously-added 125I-labelled insulin-like growth factor-1 (125I-IGF-1) was also studied. IGFBP of molecular weight about 30 and 22-24 kDa (the native form of this protein is presumed to be 29 kDa) in protein-deprived rat plasma bound more 125I-IGF-1 than those in protein-fed rat plasma. This suggested that these IGFBP in protein-deprived rat plasma are relatively unsaturated by endogenous IGF-1. The response of IGFBP to protein deprivation which was elucidated in the present investigations add further evidence to our previous assumption that IGFBP play an important role in protein nutrition.

Animals↗
PubMed1991

Changes in the urinary excretion of acid-soluble peptides in rats injected with streptozotocin or dexamethasone: a trial to estimate the changes in the rate of whole-body protein degradation in those rats.

Urinary excretion of acid-soluble peptides (ASP) was measured in rats given streptozotocin or dexamethasone. Streptozotocin-induced diabetic rats excreted increased amounts of urinary nitrogen and ASP-form amino acids. The urinary ratio for N:ASP-form leucine plus valine, which has been shown to reflect the efficiency of dietary N utilization, increased in the diabetic rats, suggesting the impaired utilization of dietary N (and re-utilization of endogenous N). Dexamethasone administration to adrenalectomized rats caused increased excretion of urinary ASP-form leucine plus valine with a concomitant increase in N excretion. However, urinary ratio for N:ASP-form leucine plus valine did not change significantly. The results suggested that dexamethasone caused increased degradation of body proteins, but maintained the efficiency of dietary N utilization or re-utilization of endogenous N. Based on the present observations and the hypothesis proposed previously by the present authors (Noguchi et al. 1988) that urinary excretion of ASP-form leucine plus valine reflects the rate of whole-body protein degradation and the urinary ratio for N:ASP-form leucine plus valine represents N utilization, the origin of urinary N in streptozotocin-diabetic and dexamethasone-administered rats is discussed.

Adrenalectomy↗
PubMed1991

HLA-DP and susceptibility to insulin-dependent diabetes mellitus in Japanese.

Human leukocyte antigen (HLA) genes are candidates for susceptibility genes in insulin-dependent diabetes mellitus (IDDM). Recently, the association of DR and DQ with IDDM has been reported, but the role of HLA-DP genes remains uncertain. To address the question, we analyzed the DPB1 gene of 20 Japanese IDDM patients and 30 control subjects using a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis (PCR-RFLP method). DPB1*0501 was the most frequent allele both in Japanese patients and control subjects. There was no appreciable association between IDDM and the DPB1 allele in Japanese. The absence of association between IDDM and DP, in spite of the known association between this disease and both DR and DQ, suggests that the HLA locus (loci) telomeric to DP encodes susceptibility to IDDM.

Alleles↗
PubMed1991

The stem cells of a primordial germ cell-derived teratocarcinoma have the ability to form viable mouse chimeras.

A euploid testicular teratocarcinoma line, STT-3, has been established from a tumor spontaneously occurring in the testis of a 129/Sv-ter male. Developmental ability of the STT-3 stem cells was tested by injecting these cells into mouse blastocysts. The frequency and the extent of chimerism were examined in mid-gestational fetuses and in live-born mice. STT-3 stem cells form viable chimeras at a high rate and differentiate into normal tissues. This is the first reported testicular teratocarcinoma-derived stem line with a proven capacity to form viable chimeric mice upon injection into the blastocysts.

Animals↗
PubMed1991

Role of interleukin-1 and prostaglandin in in vitro bone resorption induced by Actinobacillus actinomycetemcomitans lipopolysaccharide.

Lipopolysaccharide (Y4 LPS) isolated from Actinobacillus actinomycetemcomitans strain Y4 induced bone resorption in BALB/c mouse calvaria organ culture. The calcium release from LPS-low responsive C3H/HeJ mouse calvaria by Y4 LPS was very low. Indomethacin almost completely inhibited prostaglandin E2 (PGE2) production by Y4 LPS-stimulated BALB/c mouse calvaria, but did not suppress interleukin-1 (IL-1) release from the calvaria, and partially suppressed the bone resorption. Dexamethasone strongly inhibited the PGE2 and IL-1 production by Y4 LPS-stimulated BALB/c mouse calvaria, as well as Y4 LPS-induced bone resorption. Dexamethasone inhibited expression of membrane IL-1 on osteoblastic cells stimulated with Y4 LPS, but indomethacin did not. Furthermore, anti-IL-1 serum partially suppressed the calcium release from Y4 LPS-stimulated BALB/c mouse calvaria. These results suggest that both PGE2 and IL-1 participate in Y4 LPS-induced bone resorption in vitro.

Actinobacillus↗
PubMed1991

Both products of the fosB gene, FosB and its short form, FosB/SF, are transcriptional activators in fibroblasts.

We demonstrate that a member of the fos family, the fosB gene, gives rise to two transcripts by alternative splicing of exon 4, generating two proteins, FosB of 338 amino acids and a short form, FosB/SF, which contains the DNA binding and dimerization domains but not the 101 amino acids of the C terminus. FosB/SF activates an AP-1-chloramphenicol acetyltransferase construct in NIH 3T3 cells, as determined by transient and stable transfections, although more weakly than does FosB. In contrast to FosB, FosB/SF has lost its ability to repress the dyad symmetry element of the c-fos gene. FosB/SF when expressed in excess to FosB can downmodulate the activity of FosB. Constitutive expression of high levels of FosB/SF in NIH 3T3 cells has no significant inhibitory effect in the induction of cell proliferation or cell cycle progression, indicating that FosB/SF is not a negative regulator of cell growth. This conclusion is further confirmed by the observation that the majority of the Jun molecules are complexed with FosB/SF in the FosB/SF-overexpressing cells.

3T3 Cells↗
PubMed1991

Presence of vesicles containing lactate dehydrogenase in the dentin of bovine tooth germs.

The dentin was removed from bovine tooth germs, followed by the separation of the extracellular matrix vesicle fraction after collagenase treatment. Lactate dehydrogenase (LDH)-containing vesicles with a density different from that of matrix vesicles were detected in the matrix vesicle fraction. LDH in these vesicles did not result from cell lysis and vesicle capture during the preparation of the matrix vesicle fraction. The isoenzyme pattern of LDH in LDH-containing vesicles was similar to that of cytosolic LDH of odontoblasts. Other cytosolic enzymes were not detected in LDH-containing vesicles, suggesting the presence of a mechanism for specific uptake of cytosolic LDH during the in vivo formation of the vesicles.

Alkaline Phosphatase↗
PubMed1991

Localization of kallikrein in rat pineal glands.

The presence of kallikrein mRNA has been reported in the pineal gland of rats. Using an antibody to rat tissue kallikrein, we immunohistochemically examined the localization of cell components producing tissue kallikrein in this gland. The kallikrein immunoreactive cells were scattered in the parenchyma of the pineal gland. Their cell bodies were polymorphic with cell processes and a large nucleus similar to that of the pinealocyte. Frequently immunoreactive materials were seen to be localized in the perivascular areas.

Animals↗
PubMed1991

Pharmacokinetic study of selective continuous internal carotid CDDP infusion in malignant brain tumors.

Cis-diamminedichloroplatinum (CDDP) was administered by selective continuous internal carotid infusion to nine patients with malignant brain tumors, including five glioblastomas, one mixed glioma, and three metastatic tumors. CDDP was infused through a catheter in the internal carotid artery at 100 mg/hr in all cases, except one glioblastoma case in which the lower rate of 10 mg/hr was used. The results of CDDP concentration measurements were: 1) CDDP in the blood peaked at termination of CDDP infusion and then decreased slowly, 2) CDDP infiltrated intratumoral cysts and accumulated there, 3) CDDP in the cerebrospinal fluid peaked 6-18 hours after infusion, and 4) the tumor/plasma CDDP ratio varied from 2 to 8. The size of tumors decreased moderately in three of the nine cases, but no complete response was achieved. The histological changes due to CDDP were observed in the tumor tissue and were absent in the normal brain parenchyma.

Adult↗
PubMed1991

Prevention of cerebral stroke by arotinolol in salt-loaded SHRSP.

The preventive effects of long-term treatment with arotinolol on the development of cerebral stroke were examined in SHRSP fed a high salt diet. Arotinolol (4.87 mg/kg per day for 20 weeks) prevented cerebral lesions, reduced signs of stroke and delayed early mortality but did not alter blood pressure from control SHRSP, when the administration of the drug was started before the onset of hypertension. At dosage levels similar to arotinolol, both pindolol and labetalol were less effective in preventing cerebral lesions despite lower blood pressure. Propranolol produced no detectable effect on blood pressure or frequency of cerebral lesions. Furthermore, arotinolol (4.27 mg/kg per day) markedly inhibited the development of stroke without blood pressure reduction, when the administration was started after the onset of severe hypertension. These results suggest that arotinolol is more effective in preventing cerebral stroke than pindolol, labetalol and propranolol, and that factors other than blood pressure reduction may be involved in this preventive effect.

Adrenergic beta-Antagonists↗