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Biomedical subjects

M Maki

Publications and source records attributed to M Maki.

At least 163 records · Page 9Linked to original sources
PubMed1989

A region of basic amino-acid cluster in HIV-1 Tat protein is essential for trans-acting activity and nucleolar localization.

The trans-acting factor of human immunodeficiency virus (HIV), Tat, has a basic amino-acid cluster that is highly conserved among different HIV isolates. We have examined the effects of mutations in the basic region of Tat on its trans-acting activity and cellular localization. Introduction of a stop codon immediately preceding the basic region abolished the activity, while the truncated mutant with the basic region retained some activity. The basic region of Tat was replaceable with that of Rev (another trans-acting factor of HIV) but not with that of adenovirus Ela nor cellular enzyme. The result of immunofluorescence analysis revealed a correlation between the nuclear, especially nucleolar, accumulation and the activities of mutant Tat proteins.

Amino Acid Sequence↗
PubMed1989

Expression of post-transcriptional regulatory gene of HTLV-I, rex, in Escherichia coli.

Human T-cell leukemia virus type-I (HTLV-I) has a post-transcriptional regulatory gene termed rex. We have designed the rex gene to express in E. coli. Synthesis of rex protein, p27rex, was examined by immunoblot analysis using anti-p27rex antibody. No difference in electrophoretic mobility in NaDadSO4-PAGE was observed between p27rex expressed in E. coli and in an HTLV-I-infected cell line, MT-2. Slower migration of p27rex, corresponding to a 27-kD protein, in NaDodSO4-PAGE when compared with the calculated molecular weight from the amino acid sequence (Mr = 20,367) is suggested to be caused not by post-translational modification, but by the intrinsic nature of the protein, which is rich in proline and arginine.

Escherichia coli↗
PubMed1989

Role of the cysteine-rich region of HIV tat protein on its trans-activational ability.

The tat protein of human immunodeficiency virus (HIV) has a characteristic cysteine-rich region containing 7 cysteines within 16 residues. The role of this region was investigated by creation of several tat gene mutants. The activities of the novel tat gene translational products were assayed by measuring the co-transfected chloramphenicol acetyl-transferase (CAT) gene expression controlled by HIV long-terminal repeat (LTR) in the COS 7 cells. Substitution of either Cys22 with Gly, or Cys34-Gln-Val-Cys with His-Gln-Val-His, and deletion behind Lys50 of the tat protein caused a drastic loss in its activity.

Amino Acid Sequence↗
PubMed1989

Nucleolar targeting signal of human T-cell leukemia virus type I rex-encoded protein is essential for cytoplasmic accumulation of unspliced viral mRNA.

The posttranscriptional regulator (rex) of human T-cell leukemia virus type I is known to be located predominantly in the cell nucleolus and to induce the accumulation of gag and env viral mRNAs. The N-terminal 19 amino acids of rex-encoded protein (Rex) has been shown to be sufficient to direct hybrid proteins to the cell nucleolus. We have studied the function of the nucleolar targeting signal (NOS) of rex by using full-length proviral DNA and mutant rex expression plasmids. Partial deletions of the NOS sequence abolished the accumulation of unspliced cytoplasmic mRNA, although the gene products of rex mutants were found in the nucleoplasm. These results indicate that NOS sequence, or nucleolar localization of Rex, is essential for Rex function.

Animals↗
PubMed1989

Isolation and characterization of an anticoagulant protein from human placenta.

An anticoagulant protein was purified from the EDTA extract of human placental tissue. The purified protein had a molecular weight of 73,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis under both reducing and non-reducing conditions. Because this protein had the ability to bind phospholipids such as phosphatidylserine, phosphatidylinositol, and cardiolipin in the presence of Ca2+, this protein was designated as calphobindin II (CPB-II). CPB-II prolonged the clotting time of normal plasma when coagulation was induced by tissue factor, cephalin and ellagic acid or recalcification, but did not affect thrombin-initiated fibrin formation. CPB-II also inhibited the activation of prothrombin by the complete prothrombinase complex or factor Xa-phospholipid-Ca2+ but not that by phospholipid-free factor Xa. In addition, CPB-II had an inhibitory activity against phospholipase A2.

Amino Acids↗
PubMed1989

Structure and expression of cDNA for calphobindin II, a human placental coagulation inhibitor.

Calphobindin II, with Mr 73,000, is one of the human placental anticoagulant proteins. The cDNA encoding calphobindin II was obtained by screening a human placental lambda gt11 cDNA library using a specific antibody as a probe. The longest cDNA insert consisted of 2,361 nucleotides and a 64-nucleotide-long poly(A) tract. An open reading frame encoding 673 amino acids was predicted. The deduced sequence includes an 8-fold repeat of a conserved 70-amino-acid-long segment that has a high degree of sequence identity with the repeated segments in members of the Ca2+-dependent phospholipid binding protein family. The cDNA fragment including the open reading frame was introduced into the expression vector pKK223-3 and subsequently expressed in Escherichia coli JM105 cells. The resulting recombinant protein reacted with the specific monoclonal antibodies to calphobindin II and prolonged the blood coagulation time as did placental calphobindin II.

Amino Acid Sequence↗
PubMed1989

Metabolism of vitamin K dependent factors in mothers and their newborn infants.

Little is known about the absorption, excretion and transplacental transport of vitamin K in the perinatal period. From this point of view, the following studies were carried out. 1) Hepaplastin tests were performed on 65 women in the last stage of pregnancy and each coagulation factor was estimated as well. 2) Correlations were made between mothers' and babies' Hepaplastin test values. 3) Transplacental transport of vitamin K2 was studied. The general activity of vitamin K dependent factors in pregnant women was much higher than in non pregnant women. As far as the correlation between mothers' venous blood during delivery and cord venous blood is concerned, in the group of mothers with Hepaplastin test value of less than 120% of the normal adult value, the value of the Hepaplastin test was less than 30% of normal adult value in the cord venous blood. We also established that vitamin K passed through the placenta but only in small qualities.

Blood Coagulation Factors↗
PubMed1989

Effect of human epidermal growth factor on lung surfactant production in fetal rabbit.

The effect of human epidermal growth factor (hEGF) on the maturation of fetal rabbit lung was studied. On the 25th day of gestation, 0.1 ml of saline solution containing 0.1 microgram of hEGF was injected intramuscularly through uterine wall into fetuses in one horn of the uterus (hEGF treated group) and the same amount of saline solution injected into fetuses in the other horn of the uterus (saline-control group). Sham operated group was also studied; saline was injected to fetuses in both horns. On the 27th day of gestation, fetuses were delivered by cesarean section. There were no significant differences in fatal body weight and fetal lung wet weight among three groups. Total phosphatidylcholine (PC) and disaturated phosphatidylcholine (DSPC) concentrations/g dry lung weight were high in order of hEGF treated group, saline injected group and sham operated group. There were no significant differences in PC concentrations among three groups. However, DSPC concentrations in both saline-control and hEGF treated group were significantly higher than that in sham operated group (p less than 0.01). The % composition of palmitic acid in PC molecule, which is the main component of saturated fatty acid of lung surfactant, was significantly higher in hEGF group than in sham operated group (p less than 0.05). Interestingly, there were no significant differences in DSPC level and the % composition of palmitic acid between saline-control and hEGF treated group. This phenomenon might be due to so called a "neighbor effect" that hEGF injected to fetuses in one side of the uterine horn influences the fetuses in the other side of the horn through placentas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

cDNA cloning of human calpastatin: sequence homology among human, pig, and rabbit calpastatins.

cDNA of human calpastatin, an inhibitor protein specific for calpain (EC 3.4.22.17; Ca2(+)-dependent cysteine proteinase) was isolated by screening of a library prepared from human liver mRNA with pig calpastatin cDNA fragment as a probe. The primary structure of human calpastatin was deduced from the nucleotide sequence of the cDNA and compared with that of pig and rabbit calpastatins already reported. Human calpastatin consisted of 673 amino acid residues and had 78% and 77% identity to pig or rabbit calpastatins, respectively. Human calpastatin had a domain structure with four internally repetitive sequences and one N-terminal non-homologous sequence like the other calpastatins. Human calpastatin had two deletions, 22 and 13 residues long in domain L and domain 1, respectively, compared to pig or rabbit calpastatins.

Amino Acid Sequence↗
PubMed1989

[Combination chemotherapy of ovarian cancer with cisplatinum, aclarubicin and tegafur].

Two hundred fifty-nine patients with ovarian cancers were treated with the combination of CDDP, aclarubicin and tegafur. Ninety-seven of them had macroscopic diseases during the combination chemotherapy, and the overall anti-tumor response rate (CR + PR) for these patients was 54.6%. It was 60.0% for the 80 cases with epithelial ovarian cancer among them. The median survival time for the antitumor responders was 18 months, against 7 months for the non-responders and 18 months for 103 patients with advanced ovarian cancer (stage III-IV).

Aclarubicin↗
PubMed1989

Cloning and expression of the genes for calpains and calpastatins.

Calpain and calpastatin are known to be very widely distributed in animal cells. Although the physiological roles of calpain have not yet been clarified, the proteinase-proteinase inhibitor system has been suggested to play important roles in various cellular functions coupled with Ca2+ mobilization. By nucleotide sequencing of the cloned cDNAs, the primary structures of calpains and calpastatins have recently been disclosed. The expression of the genes for calpains and calpastatins in vitro as well as in vivo is being studied using cDNAs and their fragments. This paper reviews several topics on the recent progress of calpain research.

Amino Acid Sequence↗
PubMed1989

[Physiopathology of kinin forming system in reproduction].

We studied contact factors and kinin-kallikrein in normal non-pregnant and pregnant women, FXII deficient toxemia and DIC. The results obtained are as follows: 1. The levels of plasma prekallikrein, high molecular weight kininogen, kallikrein inhibitor, and C-1 INA were gradually decreased at delivery, and the levels of kallikrein like activity and bradykinin were increased during pregnancy and at the time of parturition. These facts indicate that kinin kallikrein systems played important role in uterine contraction. 2. The levels of contact factors (FXII and FXI) were lower at delivery than those of term. 3. In rat uterus, specific binding of bradykinin was observed by the method of radio receptor assay in the pelet of 10,000 X g fetal membranes, and its activity was 38%. 4. A synthetic kallikrein inhibitor (OS-291, MS) and bradykinin antagonist inhibited completely spontaneous uterine contraction of Wistar rats during delivery. 5. In the case of FXII deficiency, the levels of plasma prekallikrein, high molecular weight kininogen were normal, but at delivery, these levels were lower than those of term. The levels of kallikrein like activity which was half of normal parturition level was increased at parturition. 6. In cases of DIC (17) and severe toxemia (22), plasma prekallikrein levels were lower than the normal controls. The decrease was due to consumption of plasma prekallikrein to kallikrein activation.

Animals↗
PubMed1989

[Early diagnosis of the cervical incompetency by the ultrasonography].

To establish a reliable method for diagnosing cervical incompetency, we observed changes in the cervix by ultrasonography and tried to settle the criteria for early diagnosis. The ultrasonographic evaluation of the cervix was performed by real time B mode scanning (Aloka Echo camera SSD 650 with attached sector scanner using 3.5 MHZ transducers). The cervical length was defined as the distance from the lower edge of the fetal membranes to the edge of the portio vaginalis. In the case of normal pregnancy, the cervical length increased gradually from 14 to 24 weeks of gestation and then decreased gradually. In the case of patients who delivered before 33 weeks of gestation, the cervical length was less than -ISD. 78 of 79 cases in whom bulging of the membranes was not seen delivered at term, but 9 of 33 cases with bulging membranes delivered preterm (chi2, p less than 0.001). The criteria of cervical incompetency based on ultrasonographic findings are as follows: 1. Bulging of the fetal membranes into the endocervical canal 2. Shortening of the cervix a. the cervical length less than -ISD of the mean value b. the decrease in cervical length before 24 weeks of gestation

Cervix Uteri↗
PubMed1989

[Stimulatory action of shakuyaku on aromatase activity in cultured rat follicles].

The direct action of herbal medicines on aromatase activity was investigated in cultured rat follicles. Mature follicles were obtained from PMSG-treated immature rats. Aromatase inhibitor, 4-hydroxy-4-androstene-3,17-dione (4-OHA) was also used in the experiment. Follicles were incubated in the medium for 24 hour with toki-shakuyaku-san, Keisi-bukuryo-gan. unkei-to (10-500 micrograms) or their ingredients (100 micrograms), respectively. The addition of 4-OHA reduced estradiol secretion in a dose-response manner. The addition of each medicine (100, 500 micrograms) as well as 4-OHA (10(-5) M) restored estradiol secretion to the control level. Among the ingredients, Shakuyaku stimulated estradiol secretion in the medium in the presence or absence of 4-OHA. It is noteworthy that shakuyaku alone had a stimulatory action on aromatase activity and is the only one which is equally contained in the three medicines.

Animals↗