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Biomedical subjects

T Okazaki

Publications and source records attributed to T Okazaki.

At least 307 records · Page 17Linked to original sources
PubMed1990

Aladapcin, a new microbial metabolite that enhances host resistance against bacterial infection. Production, isolation, physico-chemical properties and biological activities.

We have constructed a new screening system for detecting microbial products that enhance host resistance against bacterial infection. It was found that a new compound with such activity is produced by a soil isolate classified as Nocardia sp. SANK 60484. The compound was isolated from the culture filtrate of the organism and named aladapcin after its amino acid composition. Aladapcin was obtained as an amphoteric white amorphous powder with the molecular formula, C13H25N5O5. It consists of 2 mol of D-alanine and 1 mol of meso-diaminopimelic acid. From the analysis of IR, 1H NMR and FAB-MS spectra, the structure was assigned to be a tripeptide. Aladapcin enhanced host resistance against an experimental Escherichia coli infection in mice at doses ranging between 1 and 100 micrograms/kg.

Adjuvants, Immunologic↗
PubMed1990

The heterogeneity of anticentromere antibodies in immunoblotting analysis.

We tested anticentromere antibody positive sera from 37 patients by immunoblotting techniques. Three antigenic polypeptides were recognized when immunoblotted against protein extracts from HeLa cell nuclei or from chromosomal segments enriched with centromere region. These were a 17 kDa (CENP-A recognized by 34 sera), an 80 kDa (CENP-B recognized by 33 sera), and a 140 kDa polypeptide (CENP-C recognized by 26 sera). There was no disease specific pattern of antigenic polypeptides, although Raynaud's phenomenon was frequent in patients with anti-CENP-B reactivities (p less than 0.01). The heterogeneity of the anticentromere antibody response in Japanese patients shows anticentromere antibody may not be a disease specific autoantibody and diagnostic marker.

Autoantibodies↗
PubMed1990

Vaginal hysterectomy without ligation of the ligaments of the cervix uteri.

An operative procedure for vaginal hysterectomy is reported. The procedure is performed without ligation of the paracervical ligaments to simplify and avoid ureteral injury. However, a portion of the cardinal ligament is ligated before peritoneal closure. In a study from 1955 to 1987, of 9,230 patients requiring vaginal hysterectomy, blood loss was less than 300 milliliters with this procedure in 83 per cent of the patients. Operative complications, such as bladder injury, occurred in 66 patients or 0.7 per cent. Ureteral injury occurred in only three patients or 0.03 per cent. From 1972 to 1987, only five of 2,460 patients (0.02 per cent) required postoperative hemostasis. These data indicate that vaginal hysterectomy without ligation of the paracervical ligaments is a safe and convenient operative method with fewer complications.

Female↗
PubMed1990

[Bone marrow suppression in gynecological patients with malignant tumor treated with combination chemotherapy cyclophosphamide, pirarubicin and cisplatin].

We treated 14 patients with cyclophosphamide, adriamycin and cisplatin (CAP), and 16 patients with cyclophosphamide, Pirarubicin and cisplatin (CTP). Hematological changes in the peripheral blood were compared in the two groups to determine whether there was any difference in bone marrow suppression. 1) The lowest leukocyte counts were similar in the two groups. The leukocyte count reached its nadir at 11.6 +/- 2.1 days in the CTP group and at 15.1 +/- 2.8 days in the CAP group, a significant difference (p less than 0.01). 2) The leukocyte count recovered rapidly in the CTP group and was significantly higher (p less than 0.01) at 3 to 4 weeks than in the CAP group, and it returned to the pretreatment level in the CTP group in the fourth week. 3) The platelet count reached its lowest level in the second week in both groups. In the CTP group, it was significantly higher (p less than 0.01) than in the CAP group. 4) Reticulocyte count reached its lowest level in the first week in both groups, and then started increasing. 5) In the CTP group, a course of treatment was 28.0 +/- 2.3 days and it was 29.5 +/- 2.3 days in the CAP group. In 28% of the CPA group, it took 30 days or more for the leukocyte count to return to normal after one course, while none of the CTP group did the leukocyte count remain low for 30 days. These results show that CTP causes more rapid bone marrow suppression (particularly leukocytopenia) than CAP, does but that a recovery is more rapid with CTP. These CTP may be a better form of treatment than CAP.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Sphingomyelin turnover induced by vitamin D3 in HL-60 cells. Role in cell differentiation.

Sphingolipid metabolism was examined in human promyelocytic leukemia HL-60 cells. Differentiation of HL-60 cells with 1 alpha, 25-dihydroxyvitamin D3 (vitamin D3; 100 nM) was accompanied by sphingomyelin turnover. Maximum turnover of [3H]choline-labeled sphingomyelin occurred 2 h following vitamin D3 treatment, with sphingomyelin levels decreasing to 77 +/- 6% of control and returning to base-line levels by 4 h. Ceramide and phosphorylcholine were concomitantly generated. Ceramide mass levels increased by 55% at 2 h following vitamin D3 treatment and returned to base-line levels by 4 h. The amount of phosphorylcholine produced equaled the amount of sphingomyelin hydrolyzed, suggesting the involvement of a sphingomyelinase. Vitamin D3 treatment resulted in a 90% increase in the activity of a neutral sphingomyelinase from HL-60 cells. The inferred role of sphingomyelin hydrolysis in the induction of cell differentiation was investigated using an exogenous sphingomyelinase. When a bacterial sphingomyelinase was added at concentrations that caused a similar degree of sphingomyelin hydrolysis as 100 nM vitamin D3, it enhanced the ability of subthreshold levels of vitamin D3 to induce HL-60 cell differentiation. This study demonstrates the existence of a "sphingomyelin cycle" in human cells. Such sphingolipid cycles (Hannun, Y., and Bell, R. (1989) Science 243, 500-507) may function in a signal transduction pathway and in cellular differentiation.

Calcitriol↗
PubMed1989

Alphoid satellite DNA is tightly associated with centromere antigens in human chromosomes throughout the cell cycle.

In this study, we have examined a DNA element specific to the centromere domain of human chromosomes. Purified HeLa chromosomes were digested with the restriction enzyme Sau3AI and fractionated by sedimentation through a sucrose gradient. Fractions showing antigenecity to anticentromere (kinetochore) serum obtained from a scleroderma CREST patient were used to construct a DNA library. From this library we found one clone which has specifically hybridized to the centromere domain of metaphase chromosomes using a biotinylated probe DNA and FITC-conjugated avidin. The clone contained a stretch of alphoid DNA dimer. To determine precisely the relative location of the alphoid DNA stretch and the centromere antigen, a method was developed to carry out in situ hybridization of DNA and indirect immunofluorescent staining of antigen on the same cell preparation. Using this method, we have found perfect overlapping of the alphoid DNA sites with the centromere antigen sites in both metaphase chromosomes and nuclei at various stages in the cell cycle. We have also observed this exact correlation at the attachment sites of artificially extended sister chromatids. These results suggest the possibility that alphoid DNA repeats are a key component of kinetochore structure.

Antigens↗
PubMed1989

A human centromere antigen (CENP-B) interacts with a short specific sequence in alphoid DNA, a human centromeric satellite.

We report the interaction between a human centromere antigen and an alphoid DNA, a human centromeric satellite DNA, which consists of 170-bp repeating units. A cloned alphoid DNA fragment incubated with a HeLa cell nuclear extract is selectively immunoprecipitated by the anticentromere sera from scleroderma patients. Immunoprecipitation of the DNA made by primer extension defines the 17-bp segment on the alphoid DNA that is required for formation of DNA-antigen complex. On the other hand, when proteins bound to the biotinylated alphoid DNA carrying the 17-bp motif are recovered by streptavidin agarose and immunoblotted, the 80-kD centromere antigen (CENP-B) is detected. DNA binding experiments for proteins immunoprecipitated with anticentromere serum, separated by gel electrophoresis, and transferred to a membrane strongly suggest that the 80-kD antigen specifically binds to the DNA fragment with the 17-bp motif. The 17-bp motif is termed the "CENP-B box." Alphoid monomers with the CENP-B box are found in all the known alphoid subclasses, with varying frequencies, except the one derived from the Y chromosome so far cloned. These results imply that the interaction of the 80-kD centromere antigen with the CENP-B box in the alphoid repeats may play some crucial role in the formation of specified structure and/or function of human centromere.

Autoantigens↗
PubMed1989

Primary structure of a ribonuclease from bullfrog (Rana catesbeiana) liver.

A pyrimidine base-specific ribonuclease was purified from bullfrog (Rana catesbeiana) liver by means of CM-cellulose column chromatography and affinity chromatography on heparin-Sepharose CL-6B, which gave single band on SDS-slab electrophoresis. The primary structure of the bullfrog liver RNase was determined. It consisted of 111 amino acid residues, including 8 half-cystine residues. From the sequence, it was concluded that three disulfide bridges in RNase A were conserved in the bullfrog RNase, that a disulfide bridge in RNase A [Cys65-Cys126 (RNase A numbering)] was deleted, and that a new disulfide bridge was created in the C-terminal part of the enzyme. In this frog RNase, the amino acid residues thought to be essential for catalysis in bovine pancreatic RNase A were conserved except for Asp121 (RNase A numbering). The sequence homology of the bullfrog liver RNase with bovine pancreatic RNase A was 30.6%. The sequence of bullfrog liver RNase was very similar to those of lectins obtained from bullfrog egg by Titani et al. [Biochemistry (1988) 26, 2189-2194] and R. japonica egg by Kamiya et al. [Seikagaku (in Japanese) (1989) 60, 733; and personal communication from Kamiya, Y., Oyama, F., Oyama, R., Sakakibara, F., Nitta, K., Kawauchi, H., and Titani, K.]. The sequence homology between the bullfrog liver RNase and the two lectins was 70.2 and 64.8%, respectively.

Amino Acid Sequence↗
PubMed1989

Diversity of cellular molecules in human cells detected by monoclonal antibodies reactive with c-myc proteins produced in Escherichia coli.

Six clones of monoclonal antibodies, MYC-1 to -6, were prepared by using two kinds of truncated c-myc proteins, p23 and p42, produced in Escherichia coli as immunogens. Analysis with enzyme-linked immunosorbent assays and immunoblotting assays with peptides produced in Escherichia coli showed that 5 clones of monoclonal antibodies, MYC-1 to -4 and -6, were reactive with c-myc protein encoded by exon 2. The remaining one clone, MYC-5, was reactive with the portion of c-myc protein encoded by exon 3. All monoclonal antibodies were also reactive with phosphorylated c-myc protein produced by insect cells infected by the baculovirus expression vector with the human c-myc gene. With immunoblotting assays using cellular lysates, MYC-1 and -3 detected bands at the levels of 58 kDa and 60 kDa, MYC-5 detected a band at 56 kDa and MYC-6 detected bands at 68 kDa and 75 kDa. All of these bands were detectable in nuclear extracts of HL-60 and Colo320, both of which have amplified c-myc genes, and also the extract of RmycYl which is the c-myc gene transfectant into 3Yl rat cells. None of them was detectable in peripheral blood mononuclear cells and 3Yl, both of which lacked activated c-myc genes. This indicates that these nuclear proteins are either c-myc gene products or molecules closely related to the c-myc gene. The remaining two clones, MYC-2 and -4, detected a band at the level of 85 kDa in cytoplasmic extracts of all the above-mentioned cells independent of the presence of the c-myc gene. This suggests that 85 kDa protein might be irrelevant to the c-myc gene. The 56 kDa protein was detectable by MYC-5 in phytohemagglutinin-stimulated peripheral blood mononuclear cells as well as leukemic cells of some patients.

Animals↗
PubMed1989

Leukoencephalopathy following treatment with carmofur: a case report and review of the Japanese literature.

A 53-year-old woman was treated with 5 courses of CAP treatment following operation for FIGO Stage Ia cancer of the ovary in September 1986. And in April 1987, she started an oral adjuvant chemotherapy with 400 mg/day of carmofur. In early June, she developed vertigo and dysarthia and was hospitalized. A CT scan showed low-density areas adjacent to both lateral ventricles, and an EEG revealed abnormally slow waves. She improved gradually after carmofur was discontinued and left the hospital in October 1987. There have been 24 reported cases of leukoencephalopathy because of carmofur in Japan, but the pathophysiological mechanism involved is not known. Since it is more common in women than in men, its incidence will probably increase in gynecological patients. Therefore, we must be on the lookout for central nervous system signs and symptoms in patients receiving adjuvant chemotherapy with carmofur.

Antineoplastic Agents↗
PubMed1989

DNA replication in Escherichia coli mutants that lack protein HU.

DNA replication in Escherichia coli cells lacking protein HU was studied. HU has been suggested to be involved in the initiation of replication from in vitro studies. The isolated HU mutants, however, are viable under normal growth conditions (M. Wada, Y. Kano, T. Ogawa, T. Okazaki, and F. Imamoto, J. Mol. Biol. 204:581-591, 1988). Chromosomal replication in the mutants appeared to be normal with respect to bidirectional replication from oriC and to its dependence on dnaA and some other dna gene products. No significant defect was observed in DNA synthesis in vitro with a crude enzyme fraction prepared from the mutant cells. These results, along with the earlier in vitro studies, suggest that other histonelike protein(s) may substitute for HU in the initiation of replication in the mutant cells. Minichromosomes were more unstable in the mutants. In the absence of either the mioC promoter, from which transcription enters oriC, or the DnaA box (DnaA protein-binding site) just upstream of the mioC promoter, the minichromosomes were especially unstable in the HU mutant and were integrated into the chromosomal oriC region under conditions selective for the plasmid-harboring cells.

Bacterial Proteins↗
PubMed1989

Studies on the biosynthesis of corrinoids and porphyrinoids. I. The labeling of oxygen of vitamin B12.

Recently the amide-oxygen has been suggested to participate in the formation of the corrin ring of vitamin B12. To confirm this hypothesis, 17O-labeled aminolevulinic acid (ALA) was prepared and administered to Propionibacterium shermanii. The isolated vitamin B12 showed only broad 17O signals in the oxygen-17 nuclear magnetic resonance (17O-NMR) spectrum. However, distinct isotope-shifted peaks were observed in the 13C-NMR spectrum of vitamin B12 isolated after incorporation of [1-13C:1,4-18O2]ALA. Of these shifted peaks, one peak (C27) showed very low intensity. This indicates that dilution of 18O occurred at the acetyl chain of the A ring of vitamin B12. This result supports the assumption that the lactone formation of the A ring promotes the ring contraction, as proposed by Eschenmoser.

Corrinoids↗
PubMed1989

New diterpenoid antibiotics, spirocardins A and B.

New antibiotics spirocardins A and B were isolated from the culture broth of an actinomycete isolated from a soil sample collected near Lake Hibara, Fukushima Prefecture, Japan. The producing strain was classified as Nocardia sp. SANK 64282. The antibiotics were isolated from the culture filtrate by solvent extraction and purified further by silica gel and preparative reverse phase column chromatography. They were primarily active against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus and limited species of Gram-negative bacteria such as Bacteroides fragilis and Klebsiella pneumoniae. They were also moderately active against several species of Mycoplasma. The molecular formulae of spirocardins A and B were C20H30O6 and C20H32O6, respectively. From their physico-chemical characteristics they were revealed to be diterpenoid antibiotics with closely related structures and the former was easily converted to the latter by the reduction with NaBH4.

Anti-Bacterial Agents↗
PubMed1989

[Effect of medroxyprogesterone acetate on side effects of CAP therapy in gynecological malignant tumors].

We concomitantly administered a large dose of medroxyprogesterone acetate (MPA) to gynecological malignant tumor patients undergoing CAP therapy (CAP). Hematological changes in the peripheral blood were compared between concomitant MPA patients and those not receiving MPA to examine the effect of MPA in reducing the marrow depression which is the major side effect of CAP. 1) Leukocyte count reached minimum at the second week of CAP in both groups. There was no significant difference in the count between the two groups. At the third week of CAP, the count improved to 84% of the pre-CAP level in patients receiving MPA and to 68% in those not receiving MPA, a significant difference (p less than 0.01). At the fourth week, leukocyte counts were 105% and 96% of pre-CAP levels, respectively. There was no difference between the two groups, but the leukocyte count returned to the pre-CAP level in the patients receiving MPA. 2) Platelet count showed changes similar to those in the leukocyte count. In patients receiving MPA, the count improved more rapidly within three weeks (118%, p less than 0.01), and was significantly higher at the fourth week (107%, p less than 0.05) than in patients not receiving MPA. 3) Reticulocyte count reached minimum in the first week, thereafter improving rapidly in both groups. No differences were noted between the two groups. 4) The periods needed for one course of CAP were 27.7 +/- 3.3 days in the patients receiving MPA and 29.5 +/- 3.7 days in the patients not receiving MPA, making for a significant difference between the two groups (p less than 0.05). These results show that MPA accelerates recovery from marrow depression caused by CAP. It is anticipated, therefore, that MPA will be helpful in the application of various chemotherapies which are expected to be frequently conducted in the future.

Antineoplastic Combined Chemotherapy Protocols↗