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Biomedical subjects

N Taniguchi

Publications and source records attributed to N Taniguchi.

772 records · Page 43Linked to original sources
PubMedDate not supplied

A three-step purification of manganese superoxide dismutase from human liver on both large and small scales.

A new method for the purification of manganese superoxide dismutase from human liver is described. The procedure involves essentially three steps: DEAE-cellulose, hydroxylapatite, and butyl-Toyopearl chromatographies. The method has several advantages: (i) its simplicity and rapidity (it takes less than 3 days), (ii) its high yield (62%) with a high specific activity (5660 units/mg of purified SOD), and (iii) its suitability for both large- and small-scale purifications.

Chromatography↗
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Increased protein glycation in cerebrospinal fluid of Alzheimer's disease.

Accumulation of advanced glycation end products occurs in the brain with ageing and was proposed to be involved in pathogenesis of Alzheimer's disease. We studied changes in the level of an early glycation product, an Amadori product, in cerebrospinal fluid (CSF) in ageing and in late-onset Alzheimer's disease. The work was carried out on 99 consecutive patients. The concentration of Amadori product in CSF correlated with CSF glucose concentration but was not changed with age (n = 70). In contrast, level of CSF Amadori product was 1.7-fold higher in Alzheimer's disease patients (n = 29) as compared with non-demented age-matched control group (n = 20; P < 0.0005), although CSF glucose concentration was similar in both groups (4.1 +/- 1.3 vs. 3.8 +/- 0.6 mmol/liter, resp.). An increased accumulation of Amadori products was found in all major proteins of CSF of Alzheimer's disease including albumin, apolipoprotein E and transthyretin. We propose that the increased early glycation of CSF proteins in the Alzheimer's patients may stimulate the formation and the consequent deposition of advanced glycation end products as well as oxidative stress in the brain.

Adult↗
PubMedDate not supplied

Isolation and properties of human alpha-fetoprotein from HepG2 cell cultures.

A relatively rapid 3-step fractionation method has been developed for the isolation of human alpha-fetoprotein from culture fluids of HepG2 cells applicable to large volumes. The protein exists as a complex with lipids or lipoproteins but an ethanol precipitation step is effective in separating it. Yields of 50-60% can be obtained from culture fluid containing 30-40 microg/ml. A minor fraction that appears to be a proteolytic product of the AFP is present in the final product.

Humans↗
PubMedDate not supplied

Umbilical cord pseudocyst in a fetus with trisomy 18.

An umbilical cord pseudocyst was detected in the 28th week of gestation in a fetus complicated with growth restriction and polyhydramnios. The combination of cord pseudocysts, growth restriction, and polyhydramnios prompted us to perform a detailed ultrasonographic examination (gray scale and three-dimensional), which revealed the presence of micrognathia, overlapping fingers, and congenital heart defects, features characteristic of trisomy 18. Karyotyping confirmed a diagnosis of trisomy 18. After spontaneous labor onset, the infant was delivered at 31 weeks of gestation, and died soon after delivery. An umbilical cord pseudocyst is a good marker for the prenatal detection of trisomy 18.

Adult↗
PubMedDate not supplied

The enzymatic basis for the conversion of nonfucosylated to fucosylated alpha-fetoprotein by acyclic retinoid treatment in human hepatoma cells: activation of alpha1-6 fucosyltransferase.

The purpose of the present study was to investigate the mechanism by which nonfucosylated alpha-fetoprotein (AFP) is converted to fucosylated AFP in human hepatoma cell lines exposed to acyclic retinoid (AR), an effective drug for the secondary prevention of hepatocellular carcinoma. AR treatment (100 microM) of HepG2 and Hep3B cells significantly increased the activity and mRNA levels of alpha1-6 fucosyltransferase (alpha1-6 FucT), the enzyme responsible for the fucosylation of AFP, leading to an increase in fucosylated glycoproteins as evidenced by lectin binding measurements. Lectin immunoelectrophoresis of AFP obtained from culture media indicated that the relative percentage of nonfucosylated AFP (L1 fraction) was decreased and alpha1-6 fucosylated AFP (L3 fraction) was increased in these hepatoma cell lines after treatment with AR. The total AFP levels were, however, markedly suppressed by AR treatment, and therefore the absolute L3 fraction on the basis of the total AFP present was extremely low. These results demonstrate that AR enhances the conversion of the L1 to the L3 fraction due to the activation of alpha1-6 FucT in human hepatoma cell lines despite clinical outcome with AR treatment and the L3 fraction of AFP. Even though the dramatic decrease in AFP is the limiting factor in the synthesis of the L3 fraction and, therefore, the absolute value of fucosylated AFP is extremely low, the conversion from L1 to L3 as judged by lectin immunoelectrophoresis represents a good marker for the progress of AR treatment.

Antineoplastic Agents↗
PubMedDate not supplied

Alteration of integrins by heparin-binding EGF-like growth factor in human breast cancer cells.

The adhesion of cancer cells to the vascular endothelium is an important step in the hematogenous metastasis of cancer. Human breast cancer cells adhere to human umbilical vein endothelial cells (HUVECs) through the interaction of E selection on HUVECs and the carbohydrate ligand sialyl Lewisx on the cancer cells. We investigated the alteration of integrin expression on human breast cancer cells, following selectin-mediated initial adhesion to HUVECs. Four cell lines derived from human breast cancer expressed alpha 2-, alpha 3-, alpha 5-, alpha 6- and beta 1-integrins. The expression of alpha 2 beta 1- and alpha 3 beta 1-integrins on BT-20 cells, strongly expressing epidermal growth factor (EGF) receptors, was markedly increased by addition of the heparin-binding EGF-like growth factor (HB-EGF). The expression of alpha 2 beta 1-integrin on SK-BR-3 cells also was increased by the addition of HB-EGF. However, no such effect of HB-EGF on the expression of integrins was observed in T-47D and MCF-7 cells, nor on expression of the EGF receptor. The increase of integrin expression in BT-20 cells was inhibited by the addition of the tyrosine kinase inhibitor genistein. HB-EGF treatment of BT-20 or SK-BR-3 cells resulted in the augmentation of cancer cell adhesion to immobilized collagen. When BT-20 cells were cocultured with HUVECs, a similar level of augmentation of cancer cell adhesion to collagen was observed. The augmentation of cancer cell adhesion to collagen was inhibited by addition of an anti-HB-EGF-neutralizing antibody. Our interpretation of the results described above is that the cancer cells receive stimulation from cytokines, such as HB-EGF, produced by vascular endothelial cells, following the initial adhesion of cancer cells via selectins. This results in a secondary increase in the expression of cell adhesion molecules, such as the beta 1-integrin family, and leads to augmentation in the adhesive activities of cancer cells at the vessel walls. We postulate that these events are the ones involved in the enhanced transmigration of cancer cells to extravascular tissues following the selectin-mediated adhesion to the endothelium.

Breast Neoplasms↗
PubMedDate not supplied

Effect of experimental cryptorchidism on alpha 1-adrenergic receptors of rat testis.

Alpha 1-adrenergic receptors play an important role in the transport of spermatozoa through seminiferous tubules to the efferent ducts leading to the epididymis. The density of alpha 1-adrenergic receptors in adult Sprague-Dawley rat testis before and during 14 days of experimental cryptorchidism was determined by binding assays with [3H]prazosin in membrane preparations. The number of maximal binding sites (Bmax) per milligram protein began to increase at 7 days after surgery (p < .05). The testicular weight and diameter of seminiferous tubules began to decrease at 5 days after surgery (p < .01). However, Bmax per testis did not differ before and during cryptorchidism. This study demonstrates that the density of alpha 1-adrenergic receptors in rat testis is not affected by cryptorchidism.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Expression of Cu,Zn-SOD, Mn-SOD and GST-pi in oral cancer treated with preoperative radiation therapy.

Radical scavengers play an important role in cancer cells defending themselves against free radicals which occur with irradiation. SOD (Cu,Zn, Mn-) and GST-pi are radical scavengers with an effect on radiation therapy. We investigated the correlation between radiation effects and expression of Cu,Zn-, Mn-SOD and GST-pi in 34 cases of oral cancer, treated with preoperative radiation therapy. In this study, 22 cases out of 34 were classified as effective and 12 cases as non-effective. Expression of Cu,Zn, Mn-SOD and GST-pi were observed in 13 (38.2%), 10 (29.4%) and 20 (58.8%) cases, respectively. Regarding the value of radiation sensitivity from expression of these proteins in the biopsy samples, no significant correlation was found between those expressions and histological effectiveness of preoperative radiation therapy. But interestingly, in 11 out of 12 of the non-effective cases, strong staining of Cu, Zn-SOD and GST-pi were shown at the residual cancer cells after preoperative radiation therapy. These results suggested that the expression of SOD (Cu,Zn-, and Mn-) and GST-pi may be not useful markers for predicting the effects of radiation therapy. However, Cu, Zn-SOD and GST-pi were increased by irradiation and may play an important role in radiation resistance and cancer cell regeneration after radiation therapy.

Adult↗
PubMedDate not supplied

Muscarinic supersensitivity and subsensitivity induced by chronic treatment with atropine and diisopropylfluorophosphate in rat submaxillary glands.

Rats were given atropine for 2 weeks and a cholinesterase inhibitor, diisopropylfluorophosphate (DFP) for 4 weeks. The secretory response of the submaxillary glands to pilocarpine and the muscarinic receptor binding to [3H]quinuclidinyl benzylate (QNB) and [3H]pirenzepine (PZ) in the submaxillary glands were investigated. Experiments were performed 48 and 24 hr after the last administration of atropine and DFP, respectively. Chronic atropine treatment enhanced the secretory response and increased the number of binding sites for [3H]QNB and [3H]PZ. The increase in number of binding sites for the 2 radioligands was almost the same. Chronic DFP treatment caused a marked decrease in the secretory response to pilocarpine, without affecting [3H]PZ and [3H]QNB binding. These results suggest that the cholinergic muscarinic M1 receptors may contribute to the development of the supersensitivity of the salivary glands caused by atropine, but not to the development of subsensitivity caused by DFP.

Animals↗
PubMedDate not supplied

Enhancement of salivary secretion by chronic anethole trithione treatment.

Effect on salivary secretion of a single dose and of chronic treatment with trithio-p-methoxyphenylpropene (anethole trithione; ANTT) was investigated in mice, rats and rabbits in relation to changes in function of the autonomic nervous system. Chronic treatment with ANTT enhanced salivary secretion induced by pilocarpine or electrical stimulation of the parasympathetic nerve, but had no effect on salivary secretion induced by isoproterenol or phenylephrine. A single dose of ANTT had no effect on salivary secretion. Chronic treatment with ANTT prevented the inhibition of parotid salivary secretion caused by atropine in rabbits. Choline acetyltransferase and acetylcholinesterase activities in rat submaxillary glands were not affected by chronic treatment with ANTT. These results suggest that chronic treatment with ANTT may enhance salivary secretion by stimulating the postjunctional secretory process involved in the parasympathetic nervous system.

Anethole Trithione↗
PubMedDate not supplied

Enhancement of the antitumor effect by the concurrent use of a monoclonal antibody and the protein-bound polysaccharide PSK in mice bearing a human cancer cell line.

The antitumor effects of a monoclonal antibody against a human cancer cell line and a protein-bound polysaccharide, PSK, obtained from cultured mycelia of Coriolus versicolor in basidiomycetes were examined. The IgG2a monoclonal antibody against the human colon cancer cell line colo 205 induced in vitro antibody-dependent macrophage-mediated cytotoxicity against the cancer cells, but only slightly suppressed the in vivo growth of the cancer cells. Concurrent use of PSK with the antibody enhanced the in vitro antibody-dependent macrophage-mediated cytotoxicity as well as the in vivo antitumor activity. These findings suggest that the combined use of a monoclonal antibody and PSK, which have different modes of action, may be useful in the treatment of cancer.

Animals↗