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Biomedical subjects

S Hata

Publications and source records attributed to S Hata.

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

Effects of recombinant human granulocyte colony stimulating factor (rG-CSF) on murine myeloid leukemia: stimulation of proliferation of leukemic cells in vitro and inhibition of development of leukemia in vivo.

We have established an experimental murine myeloid leukemia model and investigated the effects of recombinant granulocyte colony stimulating factor (rG-CSF) on myeloid leukemia in vitro and in vivo. rG-CSF stimulated colony formation by the leukemic cells in semisolid agar medium, and exponential growth of the clonogenic cells in suspension medium. Thus, rG-CSF was able to stimulate both the differentiation and self-renewal processes of the leukemic stem cells in vitro. However, 14 consecutive daily injections of rG-CSF prolonged the mean survival time of the mice implanted with the leukemic cells. This effect of rG-CSF was accompanied by a delay in the emergence of the blast cells in peripheral blood and by a decreased blast population in the spleen, suggesting that development of leukemia was suppressed in the rG-CSF-treated-mice. The prolongation of the survival time by rG-CSF was more evident when rG-CSF was administered in therapeutic combination with cyclophosphamide. These results indicate that the effect of rG-CSF on the development of leukemia is not exactly predicted from in vitro experiments.

Animals↗
PubMed1989

[Influence of tannic acid on physical and chemical properties of alpha-tricalcium phosphate-citric acid-tannic acid complex].

A mixture of alpha-tricalcium phosphate [alpha-Ca3(PO4)2; alpha-TCP] with a citric acid solution produces a hardened alpha-TCP-citric acid complex. The influence of tannic acid as an additive in the solution on the physical and chemical properties of the obtained complex was examined as a basic study for new calcium phosphate materials incorporating alpha-TCP. alpha-TCP was mixed with mixing liquids containing citric and tannic acids at various ratios [total acid = 45% (w/w)] at a powder/liquid = 2.2/1.0 (g/g). Compressive strength, setting time, and solubility & disintegration of the resulting complexes were measured by the methods specified by ADAS No. 61. After immersing the plates of the complexes in distilled water for 1 and 7 days, the surface structure of the plates was examined by using X-ray diffraction, scanning electron microscopy and IR spectroscopy. The substances solubilized and disintegrated in the water for 1 day were also examined by measuring quantitative Ca and P concentration. When the ratio of tannic acid to total acids (T/A) was higher than 30% (w/w), both setting time and solubility & disintegration increased remarkably. In the case of the complex at T/A = 30%, both setting time and solubility & disintegration showed the minimum value (6.25 min and 1.70%). For compressive strength, the maximum value (139 MPa) was obtained at T/A = 10%. Although the strength decreased markedly with increasing T/A beyond 10%, that of the complex at T/A = 30% was still a high level (103 MPa). The products on the surfaces before and after immersing the plates in distilled water were also discussed.

Calcium Phosphates↗
PubMed1989

Anaphylactic symptoms due to chlorhexidine gluconate.

Six patients who developed urticaria, dyspnea, and anaphylactic shock due to topical application of chlorhexidine gluconate solution are described. Chlorhexidine gluconate was confirmed as the causative agent of type I hypersensitivity by intradermal, scratch, and epicutaneous tests. To prevent life-threatening adverse reactions, it seems important to use chlorhexidine gluconate on wound surfaces at a concentration of 0.05%, as recommended by the manufacturer; chlorhexidine gluconate may not be suitable for application to mucous membranes.

Adolescent↗
PubMed1988

Extensive junctional diversity of rearranged human T cell receptor delta genes.

The human T cell receptor delta (TCR delta) gene encodes one component of the TCR gamma delta-CD3 complex found on subsets of peripheral blood and thymic T cells. Human TCR delta diversity was estimated by characterizing rearrangements in TCR gamma delta cell lines and determining the structures of complementary DNA clones representing functional and nonfunctional transcripts in these cell lines. One V delta segment and one J delta segment were identified in all functional transcripts, although a distinct J delta segment was identified in a truncated transcript. Further, one D delta element was identified, and evidence for the use of an additional D delta element was obtained. Thus human TCR delta genes appear to use a limited number of germline elements. However, the apparent use of two D delta elements in tandem coupled with imprecise joining and extensive incorporation of N nucleotides generates unprecedented variability in the junctional region.

Amino Acid Sequence↗
PubMed1988

Selected ion monitoring analysis of NB-818, a new calcium entry blocker in a series of dihydropyridines, in human plasma.

NB-818 is expected in clinical use to produce an antihypertensive effect and simultaneously to promote an increase in cerebral blood flow, owing to its vasodilator activity. To determine NB-818 levels in human plasma for pharmacokinetic studies, a capillary column gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) method was employed. Because NB-818 was degraded under GC conditions, stable derivatives had to be prepared for GC/MS measurements. Reaction of NB-818 with silylation agents produced derivatives quantitatively. In the silylation, however, the carbomoyl group of NB-818 was replaced by silyl moieties. NB-818 is possibly metabolized at the carbamate moiety alone, giving a compound with a hydroxymethyl group in place of the carbamoyloxymethyl group. Since this compound and NB-818 gave the same derivative, efforts were devoted to separating them. A detection limit below 0.1 ng ml-1 was attained. The calibration curve was linear in the concentration range 0.1-10 ng ml-1 (r = 0.9998), and the coefficient of variation was 5.5% and 3.1% at concentrations of 1 and 10 ng ml-1, respectively.

Calcium Channel Blockers↗
PubMed1988

Genomic organization of the human T-cell antigen-receptor alpha/delta locus.

Two clusters of overlapping cosmid clones comprising about 100 kilobases (kb) at the human T-cell antigen-receptor alpha/delta locus were isolated from a genomic library. The structure of the germ-line V delta 1 variable gene segment was determined. V delta 1 is located 8.5 kb downstream of the V alpha 13.1 gene segment, and both V segments are arranged in the same transcriptional orientation. The V alpha 17.1 segment is located between V delta 1 and the D delta, J delta, C delta region (containing the diversity, joining, and constant gene segments). Thus, V delta and V alpha segments are interspersed along the chromosome. The germ-line organization of the D delta 2, J delta 1, and J delta 2 segments was determined. Linkage of C delta to the J alpha region was established by identification of J alpha segments within 20 kb downstream of C delta. The organization of the locus was also analyzed by field-inversion gel electrophoresis. The unrearranged V delta 1 and D delta, J delta, C delta regions are quite distant from each other, apparently separated by a minimum of 175-180 kb.

Base Sequence↗
PubMed1988

Structural heterogeneity regarding local Shwartzman activity of lipid A.

The relation of chemical structure to local Shwartzman activity of lipid A preparations purified by thin-layer chromatography from five bacterial strains was examined. Two lipid A fractions from E. coli F515--Ec-A2 and Ec-A3--exhibited strong activity, similar to that of previous synthetic E. coli-type lipid A (compound 506 or LA-15-PP). The Ec-A3 fraction contained a component that appeared to be structurally identical to compound 506, and the main component of Ec-A2 fraction was structurally similar to compound 506 except that it carried a 3-hydroxytetradecanoyl group at the C-3' position of the backbone in place of a 3-tetradecanoyloxytetradecanoyl group. Free lipid A (12 C) and purified lipid A fractions, Ec-A2 (12 C) and Ec-A3 (12 C), respectively, obtained from bacteria grown at 12 C, exhibited activity comparable to Ec-A2 or Ec-A3. In these preparations, a large part of the 3-dodecanoyloxytetradecanoyl group might be replaced by 3-hexadecenoyloxytetradecanoyl group. Salmonella minnesota R595 free lipid A also contained at least two active lipid A components as seen in E. coli lipid A, but the third component corresponding to the synthetic Salmonella-type lipid A (compound 516 or LA-16-PP) exhibited low activity. A lipid A fraction, Cv-A4 from Chromobacterium violaceum IFO 12614, which was proposed to have two acyloxyacyl groups at the C-2 and C-2' positions with other acyl groups, exhibited weaker activity than the free lipid A or LPS. The purified lipid A fractions from Pseudomonas diminuta JCM 2788 and Pseudomonas vesicularis JCM 1477 contained an unusual backbone with 2,3-diamino-2,3-dideoxy-D-glucose disaccharide phosphomonoester, and these lipid A (Pd-A3 and Pv-A3) exhibited strong activity comparable to the E. coli lipid A. Thus, the present results show that the local Shwartzman reaction can be expressed by partly different lipid A structures in both hydrophilic backbone and fatty acyl residues; when they have the same backbone the potency varies markedly depending on the structure of the acyl residues.

Animals↗
PubMed1987

Identification of putative human T cell receptor delta complementary DNA clones.

A novel T cell receptor (TCR) subunit termed TCR delta, associated with TCR gamma and CD3 polypeptides, was recently found on a subpopulation of human T lymphocytes. T cell-specific complementary DNA clones present in a human TCR gamma delta T cell complementary DNA library were obtained and characterized in order to identify candidate clones encoding TCR delta. One cross-hybridizing group of clones detected transcripts that are expressed in lymphocytes bearing TCR gamma delta but not in other T lymphocytes and are encoded by genes that are rearranged in TCR gamma delta lymphocytes but deleted in other T lymphocytes. Their sequences indicate homology to the variable, joining, and constant elements of other TCR and immunoglobulin genes. These characteristics, as well as the immunochemical data presented in a companion paper, are strong evidence that the complementary DNA clones encode TCR delta.

Amino Acid Sequence↗
PubMed1987

Immunochemical proof that a novel rearranging gene encodes the T cell receptor delta subunit.

The T cell receptor (TCR) delta protein is expressed as part of a heterodimer with TCR gamma, in association with the CD3 polypeptides on a subset of functional peripheral blood T lymphocytes, thymocytes, and certain leukemic T cell lines. A monoclonal antibody directed against TCR delta was produced that binds specifically to the surface of several TCR gamma delta cell lines and immunoprecipitates the TCR gamma delta as a heterodimer from Triton X-100 detergent lysates and also immunoprecipitates the TCR delta subunit alone after chain separation. A candidate human TCR delta complementary DNA clone (IDP2 O-240/38), reported in a companion paper, was isolated by the subtractive library approach from a TCR gamma delta cell line. This complementary DNA clone was used to direct the synthesis of a polypeptide that is specifically recognized by the monoclonal antibody to TCR delta. This complementary DNA clone thus corresponds to the gene that encodes the TCR delta subunit.

Antibodies, Monoclonal↗
PubMed1987

Structurally divergent human T cell receptor gamma proteins encoded by distinct C gamma genes.

The human T cell receptor (TCR) gamma polypeptide occurs in structurally distinct forms on certain peripheral blood T lymphocytes. Complementary DNA clones representing the transcripts of functionally rearranged TCR gamma genes in these cells have been analyzed. The expression of a disulfide-linked and a nondisulfide-linked form of TCR gamma correlates with the use of the C gamma 1 and C gamma 2 constant-region gene segments, respectively. Variability in TCR gamma polypeptide size and disulfide linkage is determined by the number of copies and the sequence of a repeated segment of the constant region. Thus C gamma 1 and C gamma 2 are used to generate structurally distinct, yet functional, T3-associated receptor complexes on peripheral blood lymphocytes. Tryptic peptide mapping suggests that the T3-associated TCR gamma and delta peptides in the nondisulfide-linked form are distinct.

Amino Acid Sequence↗
PubMed1987

Killing of preimplantation mouse embryos by main ingredients of cleansers AS and LAS.

When main ingredients of cleansers, alcohol sulfate (AS) and linear alkylbenzene sulfonate (LAS), were applied to the dorsal skin of pregnant JCL:ICR mice during preimplantation period (days 0-2), significant numbers of embryos collected from the oviducts and uteri on day 3 showed severe deformity or remained at the morula stage. Most of abnormal embryos were fragmented or remained at the 1-8 cell stages, and they were either dead or dying. Even when these abnormal embryos were cultivated in the detergent-free medium, they were not recovered, while most growth-retarded embryos (morula) could grow and hatch with one or two days lag by the further in vitro cultivation. Similar results were observed with commercially obtained kitchen detergent and hair shampoo, although such embryocidal effects were not detected with natural soap and distilled water. Fertilized eggs may be specifically sensitive to synthetic detergents. Very low doses of X-rays also induced significant yields of abnormal embryos. Major difference between X-rays and detergents was that X-ray-induced abnormality appeared at the morula or blastocyst stage, while detergent-induced one did at the earlier stages.

Alcohols↗
PubMed1987

Biomechanical effects of maxillary protraction on the craniofacial complex.

The deformational effects on the human skull resulting from maxillary protraction were examined by means of strain gauges and displacement transducers. A maxillary protraction appliance was used that included a reverse headgear attached to the maxillary first molars. The protraction forces that were applied to this appliance were parallel to the occlusal plane at the following locations: the height of the maxillary arch, 5 mm above the palatal plane, and 10 mm above the Frankfort horizontal plane. The results indicated that protraction forces at the level of the maxillary arch produced an anterior rotation and forward movement of the maxilla, protraction forces 10 mm above the Frankfort horizontal plane produced a posterior rotation of the maxilla with a forward movement of nasion, and protraction forces 5 mm above the palatal plane produced a combination of parallel forward movement and a very slight anterior rotation of the maxilla. Moreover, constriction of the anterior part of the palate occurred in all cases.

Biomechanical Phenomena↗
PubMed1987

Comparative studies of phosphoenolpyruvate carboxylase from c(3) and c(4) plants.

Phosphoenolpyruvate carboxylase (PEPC) from several C(3) plants was compared to maize PEPC by immunoblotting using an antibody against maize PEPC and by peptide mapping. In C(3) gramineous plants, PEPCs of slightly different monomeric sizes were detected as two bands for wheat and barley leaves, as three bands for etiolated maize leaves and as four bands for rice leaves by SDS-polyacrylamide gel electrophoresis and immunoblotting, whereas only one PEPC band was detected for maize leaves, a C(4) plant, or tobacco leaves, a dicotyledonous C(3) plant. The peptide fragment patterns of the lower molecular weight PEPC (major band in immunoblotting) in wheat leaves was similar to that of maize PEPC in peptide mapping by protein staining or by immunological detection, but the upper one (minor band) had a different pattern from the lower one in peptide mapping by immunological detection and few peptide fragments from this were recognized by the anti-(maize) PEPC antibody. These results suggest that there are multiple forms of PEPC subunits in the gramineous plants tested, and the major PEPC has a primary structure similar to that of maize PEPC. To obtain information about the expression of PEPCs in C(3) plants, changes in the amount of PEPC protein were investigated during the greening of rice and wheat seedlings. Judging from the regulation by light, there were two types of PEPCs in greening rice seedlings, one induced by light and the other reduced by it. Greening wheat seedlings also show a PEPC band induced by light. These findings indicate that some PEPCs in C(3) gramineous plants not only have structures similar to that of maize PEPC, but also are regulated by light in a similar manner.

Journal Article↗
PubMed1987

Synthesis of sterols and 5-lipoxygenase products are required for the G1-S phase transition of interleukin-2-dependent lymphocyte proliferation.

A murine killer T cell line, G-CTLL 1, whose proliferation depends on the presence of interleukin 2 (IL-2), was used to analyze the mechanism of IL-2 action with respect to sterol synthesis and arachidonate metabolism. De novo sterol synthesis was substantially enhanced much earlier than DNA synthesis, and the rate reached a maximum at 13 hr after the addition of IL-2. Compactin, which is a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA reductase, the enzyme in the rate-limiting step of the sterol synthesis), inhibited the IL-2-induced DNA synthesis. The addition of mevalonate, the product of HMG CoA reductase, prevented the inhibition of DNA synthesis by compactin, suggesting that the supply of a sufficient amount of sterol is an essential prerequisite for IL-2 action. The IL-2-induced DNA synthesis was also inhibited by AA861, a specific inhibitor of arachidonate 5-lipoxygenase, and by other lipoxygenase inhibitors such as nordihydroguaiaretic acid and esculetin. In contrast, indomethacin, an inhibitor of arachidonate cyclooxygenase, had no effect. These findings suggest that synthesis of 5-lipoxygenase products is also a prerequisite. The inhibition of DNA synthesis was effectively inhibited only when compactin or lipoxygenase inhibitors were added early enough to block the synthesis of sterols or 5-lipoxygenase products; addition of the reagents after 3 hr decreased the inhibition with time. Therefore, about 3 hr after the addition of IL-2, several drastic intracellular changes are assumed to begin and to lead to DNA synthesis.

Animals↗
PubMed1987

[Clinical observation of twelve cases of testicular cancer].

Twelve cases of testicular cancer were treated at our Department of Urology between 1984 and 1985. The mean age of the patients was 35.2 years old. Eight of them were pure seminoma in histology, other cases were non-seminomatous germ cell tumors (NSGT). Seven cases were of stage I testicular cancer, 3 cases were of stage IIA, and 2 cases were of stage IIB. Patients with stages I and IIA seminoma were given radiation to the ipsilateral iliac and bilateral paraaortic caval nodes to the crura of the diaphragma. Two patients with stage IIB seminoma were treated with PVB therapy and retroperitoneal lymph node resection. Chemotherapy containing CDDP was effective to reduce the tumor size. Two cases were of stage I NSGT, one case was treated with high orchiectomy only, and the other case was treated with chemotherapy after high orchiectomy. Chemotherapy and retroperitoneal lymph node resection were given to two patients with stage IIA NSGT. Abnormally elevated values of lactate dehydrogenase were observed in cases with a primary tumors weight larger than about 100 g. Six of the 8 cases of pure seminoma had slightly elevated beta-human chorionic gonadotropin levels. Two cases with bilateral testicular cancer were found among the 12 cases so that necessity of meticulous palpation of remaining testis was felt. Recurrent change was not observed in any of the 12 cases so that testicular cancer is considered to be an almost curable disease.

Adult↗