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Biomedical subjects

A Matsuda

Publications and source records attributed to A Matsuda.

At least 181 records · Page 10Linked to original sources
PubMed1997

A homozygous missense mutation of the sodium/iodide symporter gene causing iodide transport defect.

Iodide transport defect is a disorder characterized by an inability of the thyroid to maintain an iodide concentration difference between the plasma and the thyroid. The recent cloning of the sodium/iodide symporter (NIS) gene enabled us to characterize the NIS gene in this disorder. We identified a homozygous missense mutation of A-->C at nucleotide +1060 in NIS complementary DNA in a male patient who was born from consanguineous marriage, had a huge goiter, and lacked the ability to accumulate iodide but was essentially euthyroid. The mutation results in an amino acid replacement of Thr354-->Pro in the middle of the ninth transmembrane domain. COS-7 cells transfected with the mutant NIS complementary DNA showed markedly decreased iodide uptake, confirming that this mutation was the direct cause of the disorder in the patient. Northern analysis of thyroid ribonucleic acid revealed that NIS messenger ribonucleic acid level was markedly increased (> 100-fold) compared with that in the normal thyroid, suggesting possible compensation by overexpression.

Amino Acid Sequence↗
PubMed1997

Assessment of beta 2- and beta 3-adrenoceptors in rat white adipose tissues by radioligand binding assay.

We investigated the characteristics of beta-adrenoceptors (beta-ARs) in rat white adipose tissues (WAT) with a radioligand receptor binding assay using (-)-[3H]-CGP12177. Scatchard analysis revealed that there are high- and low-affinity sites for (-)-[3H]-CGP12177 in WAT. The (-)-[3H]-CGP12177 bound to a high-affinity site was displaced by 1 microM propranolol. The rank of pKi values of catecholamines for the site was isoproterenol > epinephrine > norepinephrine. By contrast, BRL37344A, BRL35135A and SR59230A, beta 3-selective agonists had high affinity for the low-affinity site of (-)-[3H]-CGP12177, whereas (-)-[3H]-CGP12177 bound to a low-affinity site was completely displaced by 100 microM bupranolol but not 1 microM propranolol. The pKi values of the catecholamines (isoproterenol, norepinephrine, epinephrine) for this site were very low. In addition, the correlation between the pKi values of various beta-agonists for the low-affinity site of rat WAT and those obtained from rat cloned beta 3-ARs was significant, but those of human cloned beta 3-ARs were not. Consequently, the results suggested that the high- and low-affinity sites were beta 2-ARs and beta 3-ARs in rat WAT, respectively.

Adipose Tissue↗
PubMed1997

Hydrolytic profile for ester- or amide-linkage by carboxylesterases pI 5.3 and 4.5 from human liver.

Carboxylesterases (EC 3.1.1.1) from human liver were purified using Q-Sepharose, Sephadex G-150, isoelectrofocusing and Con A-Sepharose. The calculated molecular mass of the pI 5.3 enzyme was 120 kDa and 61 kDa from the results of Sephadex G-150 gel filtration and SDS-polyacrylamide gel electrophoresis (PAGE), respectively, suggesting that this enzyme is a dimer. On the other hand, carboxylesterase pI 4.5, with a molecular mass of 64 kDa, was a monomer. The activities of both enzymes were inhibited by typical serine enzyme inhibitors. Amino acid sequence analysis of the purified enzymes pI 5.3 and 4.5 showed high homology with rabbit carboxylesterase form 1 and 2, respectively. The results also suggested that carboxylesterase pI 5.3 is identical to the deduced amino acid sequence from cDNA for HU1, and that carboxylesterase pI 4.5 is identical to the deduced amino acid sequence from the cDNA registered as human carboxylesterase (hCE-2) in GenBank. We first purified carboxylesterase pI 4.5 and investigated its hydrolytic activity upon various drugs. The two enzymes differed in substrate specificity. Prodrugs of angiotensin-converting enzyme inhibitors, such as delapril and imidapril, were converted to active metabolites by carboxylesterase pI 5.3, but not by carboxylesterase pI 4.5. The hydrolysis velocity of temocapril by carboxylesterase pI 5.3 was 12-fold faster than by carboxylesterase pI 4.5. In contrast, aspirin, oxybutynin and procaine were hydrolyzed by only carboxylesterase pI 4.5. We also found that an amide-linkage in drugs, except for that in aniracetam, was not a good substrate for the two enzymes. Consequently, carboxylesterases pI 5.3 and 4.5 may be involved in the metabolism of various drugs containing an ester-linkage.

Amino Acid Sequence↗
PubMed1997

New neplanocin analogues. VIII. Synthesis and biological activity of 6'-C-ethyl, -ethenyl, and -ethynyl derivatives of neplanocin A.

This report describes the synthesis and antiviral effects of (6'R)-6'-C-ethynyl, -ethenyl, and -ethyl derivatives of neplanocin A (7a, 8a, and 9a, respectively) and the corresponding 6'S-diastereomers (7b, 8b, and 9b, respectively), as examples of 6'-C-substituted analogues of neplanocin A. Grignard reaction of the 6'-formyl derivative 4, which was readily prepared from neplanocin A, with ethynylmagnesium bromide gave a diastereomeric mixture of the corresponding 1,2-addition products 5a and 5b. After removal of the protecting groups, (6'R)- and (6'S)-6'-C-ethynylneplanocin A's (7a, 7b) were separated. The corresponding ethenyl derivatives 8a and 8b and ethyl derivatives 9a and 9b were prepared by catalytic hydrogenation of 7a and 7b, respectively. As compared to neplanocin A, the new neplanocin A derivatives were much weaker inhibitors of S-adenosyl-L-homocysteine hydrolase, the R-diastereomers being more inhibitory than the S-diastereomers. The decreasing order of activity was 7a > 8a > 7b > 9a > 8b > 9b. The cytotoxicity (for CEM cells) followed exactly the same order. Of these compounds, (6'R)-6'-C-ethynylneplanocin A (7a, RENPA) showed an antiviral activity spectrum that was comparable to, and an antiviral specificity that was higher than, that of neplanocin A. RENPA was particularly active against those viruses (i.e. vaccinia virus, vesicular stomatitis virus) that are known to be highly sensitive to AdoHcy hydrolase inhibitors.

Adenosine↗
PubMed1997

New neplanocin analogues. IX. A practical preparation of (6'R)-6'-C-methylneplanocin A (RMNPA), a potent antiviral agent, and the determination of its 6'-configuration. Diastereoselective deamination by adenosine deaminase.

We previously synthesized (6'R)- and (6'S)-6'-C-methylneplanocin A's (2a and 2b, respectively), and found that one of them has a potent antiviral activity, though its 6'-configuration has not been confirmed. This report describes the determination of the 6'-configuration and practical preparation of the antivirally active diastereomer. The 6'-configuration of the active diastereomer was determined as R by the modified Mosher's method as well as by synthesizing 2b from the known cyclopentenone derivative 10. A practical method for preparing the 6'R-diastereomer was developed by using diastereoselective deamination with Ado deaminase as the key step. Treatment of the diastereomeric mixture of 2a and 2b, which was prepared via an addition reaction of Me3Al with the 6'-formyl derivative 3, with Ado deaminase from calf intestine, deaminated 2b selectively to give the corresponding (6'S)-inosine congener 5, and left the desired 2a not deaminated. After silica gel column chromatography, 2a was obtained in a pure form.

Adenosine↗
PubMed1997

Inhibition by aminosalicylates of lipid peroxidation in large intestinal mucosa after mesenteric ischemia/reperfusion in the rat.

To clarify the mode of action of aminosalicylates, which are generally used as therapeutic agents for ulcerative colitis, we investigated the effect of some of the aminosalicylates on lipid peroxidation in the large intestinal mucosa after mesenteric ischemia/reperfusion in the rat. Lipid peroxidation was assessed by measuring the level of thiobarbituric-acid-reactive substances. It was found that aminosalicylates dose-dependently inhibited the elevation of the level of thiobarbituric-acid-reactive substances in the large intestinal mucosa after ischemia/reperfusion. This effect may partly contribute to the therapeutic actions of aminosalicylates in ulcerative colitis.

Aminosalicylic Acids↗
PubMed1997

Reactions between hydroxyl-radical-induced 7,8-dihydro-8-oxo-2'-deoxyguanosine precursor and the spin trap alpha-phenyl-N-tert-butylnitrone.

An N2O-saturated aqueous solution containing 2'-dG and the spin trap agent PBN was examined by ESR and HPLC-ECD methods after X irradiation. ESR examination showed that the ESR spectrum obtained consisted of signals due to the PBN-OH and PBN-H adducts. The signal intensity of PBN-H adducts was larger in the presence of 2'-dG than in the absence of 2'dG, while that of PBN-OH adducts was smaller in the presence of 2'-dG than in the absence of 2'-dG. When the OH-radical-induced 8-oxodG was measured by HPLC-ECD, the yield of 8-oxodG was found to be enhanced about twofold in the presence of PBN. By contrast, usual OH-radical scavengers (DMSO, sodium formate and mannitol) inhibited the formation of 8-oxodG beyond expectation. The enhancement of the yield of PBN-H adducts by 2'-dG and the enhancement of the 8-oxodG formation by PBN were explained by the electron transfer and subsequent proton transfer reactions from OH-radical-induced guanine-N7 radicals to PBN to form 8-oxodG and PBN-H. The present study led us to conclude that PBN reacted with the precursor radical of 8-oxodG to accelerate the formation of 8-oxodG, while OH-radical scavengers reacted with it to diminish the formation of 8-oxodG.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1997

Heterologous protein production in Acremonium chrysogenum: expression of bacterial cephalosporin C acylase and human thrombomodulin genes.

We have developed an efficient expression system for foreign genes in Acremonium chrysogenum. After inserting the foreign gene between the phosphoglycerate kinase (PGK) promoter and a terminator derived from A. chrysogenum, multiple copies of this expression unit are tandemly ligated into cosmids and the resultant cosmids are introduced into A. chrysogenum. We expressed Pseudomonas cephalosporin C acylase and a human thrombomodulin mutant protein containing the fourth, fifth, and sixth epidermal growth factor (EGF)-like structures (E456). The acylase activity in the transformants obtained using our system was several times higher than that in the transformants without the use of the system. The acylase proteins expressed had enzymatic and immunochemical properties identical to those of authentic acylase. The transformants with the expression plasmid for E456 secreted biologically active E456 protein into the culture medium. The amino terminal sequence of the purified E456 was identical to that of recombinant E456 obtained using mammalian cells.

Acremonium↗
PubMed1997

Recent trends in the management of Graves' hyperthyroidism in Japan: opinion survey results, especially on the combination therapy of antithyroid drug and thyroid hormone.

An opinion survey concerning the management of Graves' hyperthyroidism was conducted among the council members of the Japan Thyroid Association. The selection of 3 major treatments by 90 respondents for their patients was 98.6 +/- 4.2% for antithyroid drug (ATD), 7.8 +/- 12.6% for partial thyroidectomy and 5.2 +/- 8.1% for radioiodide. They expressed a movement away from the past trend of surgery because of postoperative complications and unsatisfactory therapeutic results, and they assumed a further reduction in the future. On the other hand, the frequency of radioiodide treatment was not considered to have decreased greatly, and they expected a slight increase in the future. Of the respondents, 65% suggested that hyperthyroidism should be completely cured even if the patient would fall into hypothyroidism. The major reasons for choosing surgery or radioiodide after ATD were the adverse effects of ATD and the age and social backgrounds of the patients. Large goiter size was the 3rd reason for surgery but was a minimal indicator for radioiodide. As for ATD treatment, none of the respondents reported the routine application of any uniform fixed-time therapy protocol. Japanese Graves' patients were shown to be less responsive to ATD than Caucasian patients. This was assumed to result at least from high iodide intake, and half of them had ordered their patients to restrict iodide intake. Furthermore, 78% of them had treated with a combined therapy of ATD and thyroid hormone. Most of them apply this for selected patients mainly to lower TSH receptor antibody activity, to better control their patients and to reduce the goiter size. All but 8 (9%) did not give T4 (or T3) after the cessation of ATD, and they felt this to be unnecessary, doubtful about the effect, unsuitable or even possible to induce recurrence. The excellent findings reported by Hashizume et al. (N Engl J Med 324: 947-953, 1991) are well known among them. However, most of them did not agree with the efficacy of the protocol to reduce TRAb or to improve the remission rate, and 90% of the respondents did not intend to apply the protocol immediately. In conclusion, the Japanese thyroidologists were shown to highly prefer ATD, and they intended to treat their patients for longer periods of time only by ATD until clinical remission is achieved. The combination therapy is widely used, but most of them do not consider it effective. The therapeutic protocol reported by Hashizume et al. was not accepted widely in Japan.

Antithyroid Agents↗
PubMed1997

Treatment of hyperthyroidism with a small single daily dose of methimazole: a prospective long-term follow-up study.

A prospective long-term follow-up study was performed with conventional divided doses (group C: 10 mg 3 times daily, N = 58) and a small single daily dose (group S: 15 mg once daily, N = 54) of methimazole (MMI) for the treatment of Graves' hyperthyroidism. Within 8 weeks, almost 80% of the patients in both groups became euthyroid. The mean time required to achieve a euthyroid state was 5.6 +/- 2.7 weeks in group C and 5.8 +/- 3.1 in group S. TSH binding inhibitor immunoglobulin (TBII) levels before therapy were 44.2 +/- 22.7% and 47.1 +/- 23.9% in group C and group S, respectively. A similar gradual fall in TBII levels was observed in both groups over a two-year period of treatment. MMI doses were gradually reduced to a maintenance dose (5 mg daily) after the patients became euthyroid. The patients were treated for 28 +/- 9 months and were followed up after therapy was stopped (observation period in patients who remained in remission was 12-130 (75 +/- 34) months and the interval to relapse in recurred cases was 1-98 (20 +/- 27) months). The rates of recurrence in group C were 41% at 1 yr, 54% at 2 yrs, 56% at 4 yrs and 61% at 6 yrs. In group S, these were 44%, 53%, 56% and 63%, respectively. No differences between relapse rates were observed with the two different dosage regimens. Adverse effects occurred more frequently in group C patients (24%) than in group S patients (13%). These results show that there is no difference in the clinical and immunological course or in the long-term remission rate of Graves' hyperthyroidism when the treatment is initiated with either a small single daily dose (15 mg) or the conventional regimen (10 mg 3 times daily).

Adult↗
PubMed1997

Fourteen-day oral combination dose toxicity study of CGS 16949 A (aromatase inhibitor) with 5-fluorouracil or tamoxifen in rats.

CGS 16949A, an aromatase inhibitor, was administered orally to female rats at doses of 1 and 10 mg/kg/day alone and in combination with tamoxifen (0.5 or 5 mg/kg/day) or 5-fluorouracil (20 mg/kg/day) for 14 days. CGS 16949A and tamoxifen combination: Increased food intake and body weight noted after CGS 16949A treatment were also observed following combination treatment, though to a lesser degree. Most of the clinical pathological features noted following combination treatment were similar to those induced by single compound treatment. Gross pathological and histopathological changes ascribed to the antiestrogenic action of CGS 16949A, such as increased ovarian weight, decreased uterine weight, cystic follicles and atrophied uterus and vaginal epithelium, were alleviated by combination treatment, and were comparable in severity to those caused by tamoxifen alone. No severe toxic changes were induced by combination treatment. CGS 16949A and 5-fluorouracil combination: Increased body weight noted after CGS 16949A treatment was also observed following combination treatment, though to a lesser degree. Most of the changes caused by single compound treatment, including the aforementioned effects of CGS 16949A on the genital organs, were also noted following combination treatment. There was no evidence of enhancement of the effects by combination treatment.

Administration, Oral↗
PubMed1997

Selenium level and glutathione peroxidase activity in plasma, erythrocytes and platelets of healthy Japanese volunteers.

The purpose of this study was to determine both the selenium (Se) level and glutathione peroxidase (GSH-Px) activity in plasma, erythrocytes and platelets from 51 healthy Japanese individuals. The Se levels (mean +/- SD) of plasma, erythrocytes and platelets were 117.4 +/- 15.7 micrograms/L, 0.954 +/- 0.159 microgram/g hemoglobin, and 4.93 +/- 1.52 ng/mg protein, respectively, and GSH-Px activity was 318 +/- 50 U/L, 18.0 +/- 5.0 U/g hemoglobin, and 0.142 +/- 0.035 U/mg protein, respectively. There was a negative correlation between age and the platelet Se level in men (r = -0.761, p < 0.001), and a positive correlation between the plasma and platelet GSH-Px activities in women (r = 0.663, p < 0.001).

Adult↗
PubMed1997

Correlation between intravenously supplied energy level and zinc metabolism in laparotomized rats.

We investigated the relationship between intravenous energy loading and zinc status in laparotomized rats. One of three test solutions consisting of 3% amino acid, the same amount of electrolytes (excluding zinc) and different concentrations of glucose were infused through the jugular vein for 5 d. The total energy was 109, 191 and 273 kcal/kg/d, respectively. Significantly positive correlations were observed between infusion energy and rat body weight changes (% of initial value) and between infusion energy and cumulative nitrogen balance. Regarding the zinc status, a negative correlation was found between infusion energy and plasma zinc concentration, and a positive correlation was observed between infusion energy and urinary zinc excretion. There was no significant relationship between infusion energy and hepatic zinc content. These results indicate that the zinc requirement might be increased when infusion energy is elevated and the nutritional status is improved. Zinc supplementation in the post-operative period should be considered in light of not only catabolism but also anabolism. Anabolism may be more important than catabolism in regard to zinc metabolism under relatively mild stress.

Animals↗
PubMed1997

[Antitumor effect and mechanism of a novel multifunctional nucleoside, 3'-ethynylnucleoside, on human cancers].

The antitumor activity of 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl) cytosine (ECyd) and 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl) uracil (EUrd), designed as a potential multifunctional antitumor nucleoside to inhibit RNA and DNA syntheses, was examined. ECyd and EUrd inhibited the growth of 47 kinds of cultured human cells in vitro and also showed strong antitumor effects on 15 human solid cancers xenografted into nude mice at a dose of 0.25 mg/kg (ECyd) or 2 mg/kg (EUrd) by intravenous administration for 10 consecutive days. The in vitro cytotoxic effect of ECyd and EUrd was prevented dose dependently by cytidine and uridine, suggesting that ECyd and EUrd may require phosphorylation by uridine/cytidine kinase for antitumor activity. ECyd and EUrd strongly inhibited RNA synthesis and slightly inhibited DNA synthesis. ECyd and EUrd have shown potent antitumor activity against human experimental solid type tumors with minimal toxic effects in vivo, suggesting that ECyd and EUrd is a promising agent with a unique mechanism of action for the treatment of cancer.

Animals↗
PubMed1997

Expression of macrophage migration inhibitory factor in corneal wound healing in rats.

PURPOSE: The study was conducted to evaluate the expression of macrophage migration inhibitory factor (MIF) during penetrating corneal injury. METHOD: A penetrating linear incision (2 mm) was made in the center of the right cornea with a razor blade. The expression of MIF in the lacerated eye and in the contralateral eye was examined by immunohistochemistry at 3, 6, 24, 48, and 72 hours after injury. Concentrations of MIF in the aqueous humor of the injured and contralateral eyes were also measured by enzyme-linked immunosorbent assay. The expression of MIF messenger RNA (mRNA) in the injured cornea was quantified by reverse transcription-polymerase chain reaction and subsequent Southern blot analysis. RESULTS: Positive migration inhibitory factor staining was observed in the basal cells of epithelial and endothelial cells of the normal rat cornea. The positive staining of the central corneal epithelium diminished at 3 hours after injury. At 6 hours after injury, positive MIF staining reappeared on the basal cells of the injured area, whereas the staining of the contralateral eye remained unchanged. Enzyme-linked immunosorbent assay of the aqueous humor revealed that the MIF concentration was elevated in both the injured and the contralateral eyes. The maximum concentration of aqueous MIF was observed at 6 hours after injury in both eyes. Reverse transcription-polymerase chain reaction and Southern blot analysis revealed that MIF-mRNA expression in the injured cornea increased from 6 to 48 hours after injury. CONCLUSION: The results of immunohistochemistry suggest the possibility that MIF is released from the corneal epithelial cells of the injured eye within 3 hours. Conversely, the MIF-mRNA level of the injured cornea is increased from 6 to 48 hours after injury and then diminished. In addition, unilateral corneal injury induces bilateral upregulation of MIF in the aqueous humor.

Animals↗
PubMed1997

[Plasma cell leukemia associated with monocytosis].

A 51-year-old man was admitted to our hospital in December 1993, because of fatigue. Peripheral blood tests showed a WBC of 49,400/microliter with 36% plasma cells and 35% monocytes, Hb 14.5 g/dl, and Plt 137,000/microliter. Bone marrow aspirate revealed hypercellularity with 48.7% plasma cells and 22.4% monocytes. Plasma cells in blood were positive for CD38 and PCA-1. Serum calcium, IgA and M-CSF levels were elevated to 14.1 mg/dl, 2,337 mg/dl and 2.7 ng/ml, respectively. Immunoelectrophoresis of serum and urine revealed IgA lambda type M protein and lambda type Bence Jones protein, respectively. Rearrangements of immunoglobulin heavy chain and light chain were demonstrated by Southern blotting analysis. Plasma cell leukemia (IgA lambda type) was diagnosed. He was treated with combination chemotherapy and IFN-alpha and achieved complete remission. However, he suffered a meningeal relapse in February 1995, and died in April 1996. It seems likely that the enhanced production of M-CSF by myeloma cells and/ or activated B cells stimulated monocyte production.

Humans↗
PubMed1997

[Nucleoside kinases and new types of antitumor nucleosides].

The nucleoside kinases phosphorylate nucleosides to corresponding nucleoside 5'-monophosphates. Their activities are essential for activation of chemotherapeutically important nucleoside analogues. Since, among them, deoxycytidine kinase has high activity in a wide variety of tumor tissues, a relatively low substrate specificity, and is not cell-cycle regulated, 2'-substituted-2'-deoxycytidine analogues should be suitable for antitumor antimetabolites. Gemcitabine, DMDC, and CNDAC have been developed for such analogues. These nucleosides showed potent antitumor activity against various solid tumors. They inhibited mainly DNA synthesis of tumor cells and, to some extent, inhibited RNA synthesis. To inhibit RNA synthesis of tumor cells would be important to kill solid tumor cells, which are heterogenous. ECyd was designed as an inhibitor of both DNA and RNA syntheses and showed potent antitumor activity against a variety of human tumor cells in xenografts.

Antimetabolites, Antineoplastic↗