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Biomedical subjects

T Okazaki

Publications and source records attributed to T Okazaki.

At least 235 records · Page 13Linked to original sources
PubMed1994

Cell cycle-dependent transcription from the gid and mioC promoters of Escherichia coli.

Transcription from the gid and mioC promoters, which neighbor the origin of replication of the Escherichia coli chromosome (oriC), has been implicated in the control of initiation of replication of minichromosomes. The amounts of transcripts from these two promoters on the chromosome were quantified at various times in a synchronized culture of a temperature-sensitive dnaC mutant strain. Transcription from the gid promoter was most active before the initiation of replication and was inhibited after initiation, during the time corresponding to the period of sequestration of the oriC region from the dam methyltransferase. On the other hand, transcription from the mioC promoter was inhibited before initiation and the inhibition was relieved after initiation prior to the recovery of gid transcription. The strict regulation of transcription from the gid and mioC promoters may be involved in positive and negative control of chromosomal replication, respectively, as has been suggested for minichromosome replication. The DnaA protein was involved in repression of mioC transcription, indicating that the activity of the DnaA protein changes during the cell cycle.

Bacterial Proteins↗
PubMed1994

Hereditary abnormality of luteinizing hormone resulting in discrepant serum concentrations determined by different assays.

We herein report familial defects in the molecular structure of luteinizing hormone (LH). The propositus was a 29-year-old women with repeated abortion in whom the serum LH concentration was extremely low determined by an immunoradiometric assay utilizing two monoclonal antibodies for the intact LH dimer and beta-subunit of LH (SPAC-S kit). Further studies on the serum LH concentration in this propositus by five different assay systems gave various results ranging from low to normal values. Bioassay of the propositus's LH using C57 black mice showed normal in biological activity. These data suggest that LH in the propositus is abnormal in terms of its molecular structure located in the bond region between alpha and beta subunits. A family study showed that the bioactivity of LH was normal in all family members. The serum LH was not detected in either the propositus or her brother with the SPAC-S kit even after the administration of LHRH, while the serum LH concentrations in the father, mother and sister were approximately half the normal range, indicating that the defect is hereditary and the mode of inheritance is autosomal dominant: the propositus and brother were homozygously affected, and the parents and sister heterozygously affected.

Abortion, Habitual↗
PubMed1994

Efficacy of interferon therapy in patients with chronic hepatitis C. Comparison between non-drinkers and drinkers.

BACKGROUND: Alcohol has been reported to be an important factor that modulates the development and prognosis of chronic viral hepatitis; however, little is known about interaction of alcohol intake and chronic hepatitis C. The aim of this study was to examine whether alcohol drinking affects the effectiveness of interferon (IFN) therapy for chronic hepatitis C. METHODS: Thirty-nine patients with chronic hepatitis C were divided into three groups on the basis of the amount of alcohol intake before IFN therapy: group I (n = 15), non-drinkers; group II (n = 14), less than 70 g/day; and group III (n = 10), more than 70 g/day of ethanol intake for at least 10 years. The IFN (total dose, 330 +/- 206 MU) was administered daily for 2 weeks and then intermittently. Drinkers stayed abstinent for at least 1 month before, during, and after IFN therapy. The sustained responder was defined as the patient who showed normal alanine aminotransferase (ALAT) levels continuously for more than 6 months after the therapy. The liver histology (HAI score) and serum hepatitis C virus (HCV) RNA were also examined before and after the therapy. RESULTS: There was no significant difference among the three groups in the level of ALAT before IFN therapy, age, total dose of IFN, and liver histology. The rates of sustained responders in groups I, II, and III were 53.3%, 42.9%, and 0%, respectively, resulting in a significantly lower rate in group III than in groups I (p < 0.01) and II (p < 0.01). The serum HCV-RNA turned negative after the therapy in 58.3%, 20.0%, and 12.5% of groups I, II, and III, respectively, leading to a significantly lower rate of disappearance of HCV-RNA in group III than in group I (p < 0.05). CONCLUSION: The IFN therapy for chronic hepatitis C was less effective in heavy drinkers than in non-drinkers.

Alanine Transaminase↗
PubMed1994

Isolation and characterization of new 18-membered macrolides FD-891 and FD-892.

New 18-membered macrolides FD-891 and FD-892 were discovered from the fermentation broth of Streptomyces graminofaciens A-8890 isolated from a soil sample collected at Yamanashi prefecture Japan. They induce morphological changes of HL-60 cells at low concentration below IC50s and have cytocidal activity against in vitro tumor cell lines. FD-891 showed 2 approximately 7 times stronger activity than doxorubicin whereas FD-892 was 20 approximately 100 fold weaker than FD-891 and doxorubicin.

Adenosine Triphosphatases↗
PubMed1994

Isolation and characterization of a new 12-membered macrolide FD-895.

During the course of our screening program for natural product drugs effective against multidrug resistant cells by using adriamycin resistant HL-60 cells, we have discovered a new 12 membered macrolide FD-895 in the fermentation broth of Streptomyces hygroscopicus A-9561 isolated from a soil sample collected at Iriomote Island, Okinawa prefecture, Japan. FD-895 showed stronger cytocidal activities against in vitro tumor cell lines than adriamycin. FD-895 had the same IC50 values against parent and adriamycin resistant HL-60 cells.

Anti-Bacterial Agents↗
PubMed1994

[An operative case of aortic regurgitation due to quadricuspid valve].

A case of quadricuspid aortic valve is described. A 43-year-old man admitted because of chest oppression on exercise. He had a ejection systolic murmur and decrescendo diastolic murmur. Electrocardiogram revealed severe left ventricular hypertrophy. Echocardiogram showed dilated left ventricle and supernumerary cusp between the right and left coronary cusp. Aortogram revealed quadricuspid aortic valve with grade 4 aortic regurgitation. At operation, quadricuspid aortic valve in which supernumerary cusp between right and left coronary cusp was smaller was found. Four cusps were excised and replaced with 23 mm Medronic-Hall prosthesis. His postoperative course was uneventful. Quadricuspid aortic valve has been extremely rare. Twenty operative cases has been reported. The clinical feature was presented.

Adult↗
PubMed1993

Induction of stathmin mRNA during liver regeneration.

Stathmin is a 19 kDa phosphoprotein, and is proposed to play a role in signal transduction in response to various extracellular stimuli that promote cellular growth and/or differentiation. We examined stathmin mRNA expression during development and liver regeneration in mice. Stathmin mRNA expression declined during the post-natal period and was undetected in adult liver. 36 h after partial hepatectomy, stathmin mRNA was rapidly induced and remained at elevated levels for at least 10 days. In situ hybridization experiments confirmed that stathmin mRNA expression occurred in hepatocytes. These results indicate that the stathmin gene expression appears to be repressed during the post-natal liver development, and is de-repressed by liver regeneration, which suggests that stathmin may be a good molecular marker of liver plasticity.

Aging↗
PubMed1993

Molecular diversity of the SCG10/stathmin gene family in the mouse.

SCG10 is a neuronal growth-associated protein that shares an amino acid sequence similarity with an 18- to 19-kDa phosphoprotein named stathmin (also called p19, p18, Op18, pp17, prosolin, pp20, 19K, and leukemia-associated phosphoprotein, Lap18), which is more broadly expressed in a variety of cell types of the neural, immune, and reproductive systems. The sequence similarity has suggested that SCG10 and stathmin have been derived from structurally and evolutionarily related genes. To explore the structural and evolutionary relationships between these genes, we have isolated a series of cosmid and phage clones that covers the entire region of the mouse stathmin gene and most of the mouse SCG10 gene. The SCG10 transcription unit spans at least 30 kb, while the stathmin gene is 6 kb in length. Both genes consist of five exons, and many of the intron/exon boundaries fall into the homologous regions of conserved domains of these two proteins. However, the promoter-proximal regions are distinct in the two genes, suggesting that they have evolved by fusion of the duplicated coding exons to unique promoters. Southern blot analysis indicates that SCG10 mRNA is encoded by a single gene in the mouse genome, while stathmin cDNA probes detect multiple genes. Chromosome mapping experiments reveal that the SCG10 gene is localized at the proximal region of mouse chromosome 3 and is linked to Il-7, while the stathmin gene loci are distributed to three chromosomes; the authentic stathmin gene lies on chromosome 4, whereas the loci on chromosomes 9 and 17 are likely to be pseudogenes. These data are consistent with the idea that the neuron-specific SCG10 gene evolved by duplication and modification of the more broadly expressed stathmin/Lap18 gene.

Amino Acid Sequence↗
PubMed1993

Recognition of the Qa-2k tumor antigen by T cell receptor gamma/delta of an immunopotentiator-induced tumoricidal T cell of mice.

Tumor-specific expression of Qa-2k antigen coded by the Q5k gene on various mouse tumor cells and immunological response of the host mice to the antigen have been demonstrated [Seo et al. (1992) J Exp Med 175: 547; Tanino et al. (1992) Cancer Immunol Immunother 35: 230]. The possibility was examined that Qa-2 antigen is one of the recognition target molecules of immunopotentiator-induced, H-2-nonrestricted tumoricidal lymphocytes of Qa-2-mice. Lymphocytes stimulated in vivo with P. acnes or culture-induced anomalous killers of B6.K1 mice did not exhibit significant in vitro cytotoxicity against B6.K1 lymphoblasts but lysed their Qa-2,3-congenic counterpart B6 lymphoblasts. To demonstrate the Qa-2 specificity of such cytotoxic cells more precisely, an L cell transformant clone (LQ7b/Kb), which expressed the alpha 1 and alpha 2 domains of the Qa-2 antigen (Q7b gene product), was generated by transfecting a cloned plasmid DNA containing a hybrid gene constructed from the 5' half of the Q7b gene and the 3' half of the H-2Kb gene (pQ7b/Kb). Using LQ7b/Kb cells as the target cells and the nylon-wool-nonadherent fraction of lymphocytes from P. acnes-stimulated (C3H/He x B6.K1)F1 mice (H-2k, Qa-2-) as the effector cells of the in vitro cytotoxicity reaction, the presence of cytotoxic cells that recognize the alpha 1/alpha 2 region of the Q7b gene product was demonstrated. The cytotoxic activity was dependent on T cells bearing T cell receptors of the gamma/delta type (TCR gamma/delta). The (C3H/He x B6.K1)F1 effector cells, as well as the B6.K1 effector cells also lysed BW5147 lymphoma cells (Qa-2k+) derived from AKR mice (Qa-2-, H-2k). By target-competition experiments it was shown that some of the effector cells lytic to BW5147 were identical to those that lysed LQ7b/Kb. Therefore some of the tumoricidal cells induced by the immunopotentiator interact with the target tumor cells through recognition of the alpha 1/alpha 2 region of the Qa-2k tumor antigen by TCR gamma/delta.

Adjuvants, Immunologic↗
PubMed1993

Autonomous replication of human chromosomal DNA fragments in human cells.

We have examined whether a human chromosome has distinct segments that can replicate autonomously as extrachromosomal elements. Human 293S cells were transfected with a set of human chromosomal DNA fragments of 8-15 kilobase pairs that were cloned on an Escherichia coli plasmid vector. The transfected cells were subsequently cultured in the presence of 5-bromodeoxyuridine during two cell generations, and several plasmid clones labeled in both of the daughter DNA strands were isolated. Efficiency of replication of these clones, as determined from the ratios of heavy-heavy and one-half of heavy-light molecules to total molecules recovered from density-labeled cells, was 9.4% per cell generation on the average. Replication efficiency of control clones excluded during the selection was about 2.2% and that of the vector plasmid alone was 0.3%. A representative clone p1W1 replicated in a semiconservative manner only one round during the S phase of the cell cycle. It replicated extrachromosomally without integration into chromosome. The human segment of the clone was composed of several subsegments that promoted autonomous replication at different efficiencies. Our results suggest that certain specific nucleotide sequences are involved in autonomous replication of human segments.

Blotting, Southern↗
PubMed1993

Distribution of neuromuscular junctions in the bowel affected by hypoganglionosis.

Using monoclonal antibody 171B5 against synaptic vesicle proteins, neuromuscular junctions and synapses in the muscle layers of the bowel affected by hypoganglionosis were labeled and their distribution analysed. In the hypoganglionic bowel, there were less synapses in the myenteric plexus and few neuromuscular junctions compared to normal bowels. The bowel dysmotility of the patient with hypoganglionosis appears to be due to inadequate innervation between ganglion cells and smooth muscle cells.

Colon↗
PubMed1993

[Infection rate of Chlamydia trachomatis in sexual partners from pregnant women with Chlamydia trachomatis infection].

We investigated the infection rate of Chlamydia trachomatis in sexual partners who had pregnant wives with C. trachomatis diagnosed by means of serum-antibody test (Ipazyme) or antigen test (Chlamydiazyme, IDEIA-chlamydia). Antibody-positive rate was 60.4% (90/149 cases), and antigen-positive rate was 7.4% 11/149 cases). All cases with Chlamydial antigen had anti-Chlamydial antibody. Eleven cases with Chlamydial antigen had no symptom of urethritis. Among these cases, eight cases had abnormal laboratory findings. However, the other three cases who had no abnormal finding were careers of C. trachomatis. In this study, sexual partners who had Chlamydial antigen were few, however, those who had anti-chlamydial antibody were many. Therefore, C. trachomatis will disseminate among many families as a latent infection.

Adult↗
PubMed1993

Small airway involvement in mixed connective tissue disease.

We studied pulmonary functions in 17 female patients with mixed connective tissue disease (MCTD) to detect early pulmonary involvement in this disease; in 8 of the 17 patients follow-up studies were also performed at 1.2- to 5.9-year intervals. In the first pulmonary function tests, decreases in vital capacity (VC) and diffusing capacity (DLCO) were observed in 6 (35%) and 8 (47%) patients, respectively. The ratio of forced expiratory volume in one second to VC was normal in all the patients, but pulmonary resistance and static compliance were abnormal in 6 (35%) and 10 (59%) patients, respectively. However, frequency dependence of dynamic compliance was found in all 16 patients tested. Moreover, 4 (24%) of the 17 patients had normal DLCO and DLCO-to-alveolar volume ratio (DLCO/VA). Reductions in DLCO and DLCO/VA were significantly correlated with the disease duration. These results suggest that small airway obstruction is an early and frequent indication of functional pulmonary impairment, and that impairment of alveolar gas exchange is progressive in patients with MCTD.

Adolescent↗
PubMed1993

Isolation of trehalamine, the aglycon of trehazolin, from microbial broths and characterization of trehazolin related compounds.

Trehalamine, (3aR,4R,5S,6S,6aS)-2-amino-4-(hydroxymethyl)-3a,5,6,6a- tetrahydro-4H-cyclo-pent[d]oxazole-4,5,6-triol (1) and D-glucose were obtained by acid hydrolysis of trehazolin (3), a trehalase inhibitor produced by actinomycetes. More vigorous hydrolytic treatment of trehazolin afforded an aminocyclitol, (1R,2S,3R,4S,5R)-5-amino-1- (hydroxymethyl)cyclopentane-1,2,3,4-tetraol (2). Trehalamine, the aglycon of trehazolin, was also found in the culture broths of two trehazolin producing strains, Micromonospora sp. SANK 62390 and Amycolatopsis sp. SANK 60791. These trehazolin related compounds trehalamine (1) and 2 were poor inhibitors of trehalase (1; IC50 1.8 x 10(-4) M, 2; > 5.0 x 10(-4) M). On the other hand they inhibited more potently rat intestinal sucrase (1; IC50 6.8 x 10(-5) M) and sweet almond beta-glucosidase (2; IC50 5.6 x 10(-6) M) than trehazolin.

Actinobacteria↗
PubMed1993

Milbemycins alpha 11, alpha 12, alpha 13, alpha 14 and alpha 15: a new family of milbemycins from Streptomyces hygroscopicus subsp. aureolacrimosus. Taxonomy, fermentation, isolation, structure elucidation and biological properties.

Streptomyces hygroscopicus subsp. aureolacrimosus SANK 60286 produces a new family of milbemycins, named milbemycins alpha 11, alpha 12 [corrected], alpha 13, alpha 14 and alpha 15, together with other milbemycins. Their structures are 3-methyl-2-butenoyloxy and 3-methylbutyroyloxy derivatives at C-4a of milbemycins A3 and A4, or 3-methyl-2-pentenoyloxy derivative at C-4a of milbemycin A3, respectively. Milbemycin alpha 14, 3-methyl-2-butenoyloxy derivative, especially possesses a potent acaricidal activity.

Animals↗
PubMed1993

Novel microbial metabolites of the phoslactomycins family induce production of colony-stimulating factors by bone marrow stromal cells. I. Taxonomy, fermentation and biological properties.

Three metabolites were isolated from the culture broth of an actinomycete strain identified as Streptomyces platensis SANK 60191, that induce the production of colony-stimulating factors (CSFs) by stromal cell line KM-102 at ED50 concentrations from 40 to 200 ng/ml. The compounds induced quantities of granulocyte CSF (G-CSF) and granulocyte-macrophage CSF (GM-CSF) comparable to those induced by interleukin-1, a strong CSF inducer. These metabolites were called leustroducsins (A, B and C) and were later found to be structurally related to phoslactomycins. This is the first report of CSF inducing activity by members of the phoslactomycin class.

Antifungal Agents↗
PubMed1993

[A case of intralobar pulmonary sequestration associated with an accessory diaphragm].

We report one operated case (a 71-year-old female) of intralobar pulmonary sequestration (Pryce's type 1) associated with an accessory diaphragm. The patient had hemoptysis for 5 years. Lateral chest X-ray showed an oblique line attaching to the central portion of the right diaphragm. Selective angiography and ultrasonography showed an aberrant vessel originating from the abdominal aorta. At the time of operation, the pleural cavity was divided into two compartments by a fibrous membrane. The bronchus of the lower compartment and the pulmonary veins ran through a hole in the accessory diaphragm. The aberrant artery flowed into the parts of lung in the upper and lower compartments.

Abnormalities, Multiple↗