Biomedical subjects

H Tokumitsu

Publications and source records attributed to H Tokumitsu.

At least 37 records · Page 2Linked to original sources

PubMed1997

Degradation of a novel tripeptide, tert-butoxycarbonyl-Tyr-Leu-Val-CH2Cl, with inhibitory effect on human leukocyte elastase in aqueous solution and in biological fluids.

The stability of tert-butoxycarbonyl-Tyr-Leu-Val-CH2Cl (YLV) with inhibitory effect on human leukocyte elastase was investigated in aqueous solution, alpha-chymotrypsin solution and biological media. In all cases studied here, the degradation was observed as a pseudo-first order reaction. The half-life for the degradation of YLV in an aqueous solution of pH 7.4 at 37 degrees C was 35.9 h. YLV was most stable at about pH 3.8-5.8 and the effect of temperature was explained by the Arrhenius equation. The activation energies of the degradation in aqueous solutions at pH 2.0, 4.8, and 7.4 were 24.6, 22.1 and 23.4 kcal/mol, respectively. The degradation products in aqueous solution were analyzed by HPLC-MS and were estimated as Boc-Tyr-Leu-Val-CH2OH at pH 7.4 and H2N-Tyr-Leu-Val-CH2Cl at pH 2.0. In a bovine pancreas alpha-chymotrypsin solution at 37 degrees C, the half-life of YLV was 15 min at 25.6 micrograms/ml of alpha-chymotrypsin solution. In the rat plasma, the half-life of YLV was 42.4 min (YLV 26.7 micrograms/ml plasma), and in rat liver, lung and spleen homogenates, the degradation rate constants of YLV were 37.6, 10.3 and 23.5 times larger than that in plasma solution, respectively (all fluids containing 5 mg protein/ml). YLV was less stable than nafarelin acetate, secretin, adrenocorticotropic hormone (ACTH) and gonadorelin in an aqueous solution of pH 7.4.

Animals↗

PubMed1997

[Successful TSH suppression therapy with triiodothyronine in a patient with pulmonary metastases from differentiated thyroid carcinoma in the absence of 131I uptake].

A 28-year-old woman was referred to us to undergo 131I therapy who had multiple pulmonary metastases from papillary thyroid carcinoma after total thyroidectomy. There was no increased accumulation of a tracer in the pulmonary metastatic foci on whole-body scanning using a 111 MBq diagnostic dose of 131I. However, the pulmonary metastases were gradually decreased in size, and then clearly reduced 8 months after the start of TSH suppression therapy, which was maintained by T3 instead of T4 to bring down the serum TSH level below 0.1 microU/ml. Reduction rates of the foci were 33-76% on chest X-ray. The reduction was confirmed and no new lesions were found on the serial CT scans. Serum thyroglobulin level was lowered 80 to 25 ng/ml by this suppression therapy and progression of disease was not observed under a 54 months' T3 treatment. Thus, TSH suppression therapy might improve survival of patients with differentiated thyroid cancer.

Adult↗

PubMed1996

Regulation of mitogen-activated protein kinases by a calcium/calmodulin-dependent protein kinase cascade.

Membrane depolarization of NG108 cells gives rapid (< 5 min) activation of Ca2+/calmodulin-dependent protein kinase IV (CaM-KIV), as well as activation of c-Jun N-terminal kinase (JNK). To investigate whether the Ca2+-dependent activation of mitogen-activated protein kinases (ERK, JNK, and p38) might be mediated by the CaM kinase cascade, we have transfected PC12 cells, which lack CaM-KIV, with constitutively active mutants of CaM kinase kinase and/or CaM-KIV (CaM-KKc and CaM-KIVc, respectively). In the absence of depolarization, CaM-KKc transfection had no effect on Elk-dependent transcription of a luciferase reporter gene, whereas CaM-KIVc alone or in combination with CaM-KKc gave 7- to 10-fold and 60- to 80-fold stimulations, respectively, which were blocked by mitogen-activated protein (MAP) kinase phosphatase cotransfection. When epitope-tagged constructs of MAP kinases were co-transfected with CaM-KKc plus CaM-KIVc, the immunoprecipitated MAP kinases were activated 2-fold (ERK-2) and 7- to 10-fold (JNK-1 and p38). The JNK and p38 pathways were further investigated using specific c-Jun or ATF2-dependent transcriptional assays. We found that c-Jun/ATF2-dependent transcriptions were enhanced 7- to 10-fold by CaM-KIVc and 20- to 30-fold by CaM-KKc plus CaM-KIVc. In the case of the Jun-dependent transcription, this effect was not due to direct phosphorylation of c-Jun by activated CaM-KIV, since transcription was blocked by a dominant-negative JNK and by two MAP kinase phosphatases. Mutation of the phosphorylation site (Thr196) in CaM-KIV, which mediates its activation by CaM-KIV kinase, prevented activation of Elk-1, c-Jun, and ATF2 by the CaM kinase cascade. These results establish a new Ca2+-dependent mechanism for regulating MAP kinase pathways and resultant transcription.

Activating Transcription Factor 2↗

PubMed1996

A dual computed tomography linear accelerator unit for stereotactic radiation therapy: a new approach without cranially fixated stereotactic frames.

PURPOSE: To perform stereotactic radiation therapy (SRT) without cranially fixated stereotactic frames, we developed a dual computed tomography (CT) linear accelerator (linac) treatment unit. METHODS AND MATERIALS: This unit is composed of a linac, CT, and motorized table. The linac and CT are set up at opposite ends of the table, which is suitable for both machines. The gantry axis of the linac is coaxial with that of the CT scanner. Thus, the center of the target detected with the CT can be matched easily with the gantry axis of the linac by rotating the table. Positioning is confirmed with the CT for each treatment session. Positioning and treatment errors with this unit were examined by phantom studies. Between August and December 1994, 8 patients with 11 lesions of primary or metastatic brain tumors received SRT with this unit. All lesions were treated with 24 Gy in three fractions to 30 Gy in 10 fractions to the 80% isodose line, with or without conventional external beam radiation therapy. RESULTS: Phantom studies revealed that treatment errors with this unit were within 1 mm after careful positioning. The position was easily maintained using two tiny metallic balls as vertical and horizontal marks. Motion of patients was negligible using a conventional heat-flexible head mold and dental impression. The overall time for a multiple noncoplanar arcs treatment for a single isocenter was less than 1 h on the initial treatment day and usually less than 20 min on subsequent days. Treatment was outpatient-based and well tolerated with no acute toxicities. Satisfactory responses have been documented. CONCLUSION: Using this treatment unit, multiple fractionated SRT is performed easily and precisely without cranially fixated stereotactic frames.

Brain Neoplasms↗

PubMed1996

Requirements for calcium and calmodulin in the calmodulin kinase activation cascade.

We have previously purified and cloned rat brain Ca2+/calmodulin-dependent protein kinase kinase (CaM-KK), and the 68-kDa recombinant CaM-KK activates in vitro both CaM-kinase IV (CaM-K IV) and CaM-K I (Tokumitsu, H., Enslen, H., and Soderling, T. R. (1995) J. Biol. Chem. 270, 19320-19324). In the present study we have determined that activation of CaM-K IV through phosphorylation of Thr196 by CaM-KK is triggered by elevated intracellular Ca2+ in intact cells and requires binding of Ca2+/CaM to both enzymes. An expressed fragment of CaM-K IV (CaM-K IV178-246), which contains the activating phosphorylation site (Thr196) but not the autoinhibitory domain or the CaM-binding domain, still required Ca2+/CaM for phosphorylation by wild-type CaM-KK. A truncated mutant of CaM-KK (CaM-KK1-434) phosphorylated CaM-K IV178-246 in a Ca2+/CaM-independent manner, but this constitutively active CaM-KK1 434 required Ca2+/CaM for phosphorylation and activation of wild-type CaM-K IV. These results demonstrate that binding of Ca2+/CaM to both CaM-K IV and CaM-KK is required for the CaM-kinase cascade. Both CaM-KK and CaM-K IV appear to have similar Ca2+/CaM requirements with EC50 values of approximately 100 nM. Studies using co-expression of CaM-K IV with CaM-KK in COS-7 cells demonstrated that CaM-KK rapidly activated both total and Ca2+/CaM-independent activities of wild-type CaM-K IV, but not the Thr196 --> Ala mutant, upon ionomycin stimulation.

Alanine↗

PubMed1996

Effects of endoscopic variceal sclerotherapy on azygos vein blood flow and systemic haemodynamics.

The present study was designed to determine the systemic haemodynamic effects of obliterating oesophageal varices by endoscopic sclerotherapy. We evaluated systemic and splanchnic haemodynamics before and after the first course of sclerotherapy in cirrhotic patients. The baseline cardiac index was significantly correlated with baseline azygos vein blood flow (r = 0.64; P < 0.01) and the azygos vein blood flow and cardiac index significantly decreased (-33% and -16%, respectively; P < 0.01) following sclerotherapy. The systemic vascular resistance index was also increased significantly (+ 20%; P < 0.01) in these patients. Moreover, the per cent change in azygos vein blood flow was directly correlated with that of the cardiac index (r = 0.51; P < 0.03). We conclude from these findings that the obliteration of portosystemic collaterals by sclerotherapy significantly reverses hyperdynamic circulation in such patients via a decrease in cardiac preload. The blood flow of the portosystemic shunt per se is a leading contributor to the hyperdynamic circulation observed in patients with well-developed portal systemic collateral vessels.

Adult↗

PubMed1995

Characterization of a Ca2+/calmodulin-dependent protein kinase cascade. Molecular cloning and expression of calcium/calmodulin-dependent protein kinase kinase.

Recent studies have demonstrated that Ca2+/calmodulin-dependent protein kinase IV (CaM-kinase IV) can mediate Ca(2+)-dependent regulation of gene expression through the phosphorylation of transcriptional activating proteins. We have previously identified and purified a 68-kDa rat brain CaM-kinase kinase that phosphorylates and increases total and Ca(2+)-independent activities of CaM-kinase IV (Tokumitsu, H., Brickey, D. A., Gold, J., Hidaka, H., Sikela, J., and Soderling, T. R. (1994) J. Biol. Chem. 269, 28640-28647). Using a partial amino acid sequence of the purified brain kinase, a CaM-kinase kinase cDNA was cloned from a rat brain cDNA library. Northern blot analysis showed that CaM-kinase kinase mRNA (3.4 kilobases) was expressed in rat brain, thymus, and spleen. Sequence analyses revealed that the cDNA encoded a 505-amino acid protein, which contained consensus protein kinase motifs and was 30-40% homologous with members of the CaM-kinase family. Expression of the cDNA in COS-7 cells yielded an apparent 68-kDa CaM-binding protein, which catalyzed in vitro activation in the presence of Mg2+/ATP and Ca2+/ CaM of CaM-kinases I and IV but not of CaM-kinase II. Co-expression of CaM-kinase kinase with CaM-kinase IV gave a 14-fold enhancement of cAMP-response element-binding protein-dependent gene expression compared with CaM-kinase IV alone. These results are consistent with the hypothesis that CaM-kinases I and IV are regulated through a unique signal transduction cascade involving CaM-kinase kinase.

Amino Acid Sequence↗

PubMed1995

The long amino-terminal tail domain of annexin XI is necessary for its nuclear localization.

Annexin XI is a newly identified annexin which localizes mainly in the nucleus of rat embryonic fibroblasts. There are no typical nuclear localization signals (NLS) in the molecule. To define the region responsible for its nuclear localization, a series of mutants and chimeric cDNA were constructed. These were transiently expressed in COS-7 cells, and the subcellular distributions of the mutants and chimeric proteins were determined by indirect immunofluorescence microscopy. Wild-type annexin XI was located predominantly within the nucleus. Deletion of the N-terminal tail domain (residues 3-196) changed the distribution of the protein from the nucleus to the cytoplasm whereas deletion of the C-terminal core domain (residues 208-504) still kept the protein sorting to the nucleus. Three other mutants lacking 60-80 amino acids in the N-terminal region (residues 3-61, 61-115, and 115-197, respectively) no longer efficiently imported into the nucleus. Furthermore, Escherichia coli beta-galactosidase polypeptide was efficiently localized to the nucleus only when fused with the whole N-terminal region of annexin XI (residues 1-207), not with part of the N-terminal region. In primary cultured rat hepatocytes, annexin XI was distributed in the cytoplasm but not in the nucleus. These results suggest that the whole N-terminal tail domain of annexin XI is necessary and sufficient for its nuclear localization, and may function as NLS in a cell-type specific manner.

Animals↗

PubMed1995

Phosphorylation of CREB by CaM-kinase IV activated by CaM-kinase IV kinase.

Previous reports have shown that CaM-kinase IV can phosphorylate the transcription factor CREB in vitro on Ser133. Furthermore, transfected CaM-kinase IV can activate CREB-dependent transcription, but at a lower efficiency than the cAMP-kinase. In this paper we examine the kinetics and site-specificity of CREB phosphorylation in vitro by CaM-kinase IV after its phosphorylation and activation by a newly discovered brain CaM-kinase IV kinase. Our results show that activated CaM-kinase IV has the same Km (1-5 microM) for CREB phosphorylation, but the Vmax is about 30-fold higher than with non-activated CaM-kinase IV. Activated CaM-kinase IV still shows specificity for phosphorylation of Ser133, the site necessary for transactivation by CREB. It is likely that the lower efficiency of transcriptional activation by transfected CaM-kinase IV in previous studies was due to the fact that the CaM-kinase IV was not activated by CaM-kinase IV kinase.

Amino Acid Sequence↗

PubMed1995

NFATx, a novel member of the nuclear factor of activated T cells family that is expressed predominantly in the thymus.

The nuclear factor of activated T cells (NFAT) regulates cytokine gene expression in T cells through cis-acting elements located in the promoters of cytokine genes. Here, we report the cDNA cloning, chromosomal localization, and initial characterization of a transcription factor related to NFATp and NFATc. The novel molecule, designated NFATx, exhibits in its middle a region very similar to the Rel homology domain in NFATc and NFATp. The amino-terminal region of NFATx also shows significant similarities to corresponding sequences in NFATc and NFATp and contains three copies of a conspicuous 17-residue motif of unknown function. We provide evidence showing that NFATx can reconstitute binding to the NFAT-binding site from the interleukin 2 promoter when combined with AP1 (c-Fos/c-Jun) polypeptides and that NFATx is capable of activating transcription of the interleukin 2 promoter in COS-7 cells when stimulated with phorbol ester and calcium ionophore. NFATx mRNA is preferentially and remarkably found in the thymus and at lower levels in peripheral blood leukocytes. The expression pattern of NFATx, together with its functional activity, strongly suggests that NFATx plays a role in the regulation of gene expression in T cells and immature thymocytes.

Amino Acid Sequence↗

PubMed1994

Activation mechanisms for Ca2+/calmodulin-dependent protein kinase IV. Identification of a brain CaM-kinase IV kinase.

This manuscript examines the mechanisms by which Ca2+/calmodulin-dependent protein kinase IV (CaM-kinase IV) is activated through the binding of Ca2+/CaM and by phosphorylation. Studies with the synthetic autoinhibitory domain peptides of CaM-kinase II indicate that CaM-kinase IV has a similarly located autoinhibitory domain, and this was confirmed since site-directed mutagenesis of this region (HMDT308 to DEDD and FN317 to DD) generated fully active Ca2+/CaM-independent kinases. Total activities of purified, baculovirus-expressed wild type and mutant kinases were increased 2-fold by intramolecular autophosphorylation, but this reaction was extremely slow (1-2 h) and probably not physiological. However, CaM-kinase IV can be activated by brain CaM-kinase IV kinase resulting in large increases in both total (5-7-fold) and Ca2+/CaM-independent (> 20-fold) CaM-kinase IV activities. This activation reaction required Mg2+/ATP and Ca2+/CaM, was intermolecularly catalyzed, and was reversed by protein phosphatase 2A. Activation of CaM-kinase IV resulted in a 10-fold decrease in Km for syntide-2 with little effect on Km for ATP or Vmax. CaM-kinase IV kinase was highly purified from rat brain extract and was shown to be a 68-kDa monomer. The results of this study demonstrate that CaM-kinase IV does have an autoinhibitory domain within residues His305-Lys321 that suppresses kinase activity in the absence of Ca2+/CaM. CaM-kinase IV is not significantly activated by autophosphorylation, but it can be activated 10-fold by a CaM-kinase IV kinase. This kinase cascade activation mechanism may be important for the physiological function of CaM-kinase IV such as transcriptional regulation through phosphorylation of cAMP responsive element binding protein (Enslen, H., Sun, P., Brickey, D., Soderling, S. H., Klamo, E., and Soderling, T.R. (1994) J. Biol. Chem. 269, 15520-15527).

Amino Acid Sequence↗

PubMed1994

Calcineurin potentiates activation of the granulocyte-macrophage colony-stimulating factor gene in T cells: involvement of the conserved lymphokine element 0.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) are produced by stimulation with phorbol-12-myristate acetate (PMA) and calcium ionophore (A23187) in human T cell leukemia Jurkat cells. The expression of GM-CSF and IL-2 is inhibited by immunosuppressive drugs such as cyclosporin A (CsA) and FK506. Earlier studies on the IL-2 gene expression showed that overexpression of calcineurin (CN), a Ca2+/calmodulin-dependent protein phosphatase, can stimulate transcription from the IL-2 promoter through the NF-AT-binding site. In this study, we obtained evidence that transfection of the cDNAs for CN A (catalytic) and CN B (regulatory) subunits also augments transcription from the GM-CSF promoter and recovers the transcription inhibited by CsA. The constitutively active type of the CN A subunit, which lacks the auto-inhibitory and calmodulin-binding domains, acts in synergy with PMA to activate transcription from the GM-CSF promoter. We also found that the active CN partially replaces calcium ionophore in synergy with PMA to induce expression of endogenous GM-CSF and IL-2. By multimerizing the regulatory elements of the GM-CSF promoter, we found that one of the target sites for the CN action is the conserved lymphokine element 0 (CLE0), located at positions between -54 and -40. Mobility shift assays showed that the CLE0 sequence has an AP1-binding site and is associated with an NF-AT-like factor, termed NF-CLE0 gamma. NF-CLE0 gamma binding is induced by PMA/A23187 and is inhibited by treatment with CsA. These results suggest that CN is involved in the coordinated induction of the GM-CSF and IL-2 genes and that the CLE0 sequence of the GM-CSF gene is a functional analogue of the NF-AT-binding site in the IL-2 promoter, which mediates signals downstream of T cell activation.

Animals↗

PubMed1993

Binding site of annexin XI on the calcyclin molecule.

We purified rabbit calcyclin of S100 family protein and a calcyclin associated protein which has proved to be a novel annexin, annexin XI. Using a co-precipitation assay of annexin XI with phospholipid, the binding site of annexin XI on calcyclin was examined. The peptide fragment of calcyclin, CNBr-3 (residues 1-57), digested with cyanogen bromide completely inhibited the interaction of native calcyclin with annexin XI, while CNBr-1 (residues 83-90) and CNBr-2 (residues 58-82) did not affect the binding. We then constructed and expressed recombinant cDNAs for wild type and four different deletion mutants lacking N-terminal portions. The wild type (wt) and mt1 mutant lacking three amino acids from N-terminal bound to annexin XI with phosphatidylserine and Ca2+, whereas mt2, mt3 and mt4 with seven, twelve and eighteen amino acids deleted, respectively, did not bind to annexin XI. Moreover, the truncated mutant from residues 4 to 7 (mt5) decreased the binding capacity. These observations suggest that four amino acids (residues 4-7) at the N-terminal portion of calcyclin play an important role in the interaction of calcyclin with annexin XI.

Amino Acid Sequence↗

PubMed1993

Purification of the 120 kDa component of the human nuclear factor of activated T cells (NF-AT): reconstitution of binding activity to the cis-acting element of the GM-CSF and IL-2 promoter with AP-1.

The cis-acting element of the granulocyte-macrophage colony-stimulating factor (GM-CSF) promoter, CLE0, is required for stimulation dependent expression of the GM-CSF gene by phorbol ester (PMA) and calcium ionophore (A23187) in T cells. We recently obtained evidence that NF-CLE0 gamma, one of the CLE0-binding factors, is similar to the nuclear factor of activated T cells, NF-AT. In the present study, we show that the affinity-purified NF-AT from nuclear extracts of human Jurkat T cells stimulated with both PMA and A23187 bound strongly to the CLE0 element and formed a NF-CLE0 gamma complex. This DNA-protein complex was competitively inhibited by oligonucleotides containing NF-AT and AP-1 binding sites, suggesting that the CLE0 gamma complex is identical to NF-AT and contains AP-1 proteins. Here, one component of NF-AT with an apparent molecular mass of 120 kDa on SDS-polyacrylamide gel electrophoresis was purified to near homogeneity by Mono Q chromatography. The purified 120 kDa protein reconstitutes NF-AT binding in combination with recombinant cJun/cFos heterodimer. Furthermore, we demonstrate that binding of this 120 kDa protein to both the NF-AT and the CLE0 sequences can be reconstituted with the addition of affinity-purified Jurkat AP-1 proteins. These results indicate that NF-AT (NF-CLE0 gamma), which is composed of the 120 kDa nuclear protein and AP-1 proteins, regulates the stimulation-dependent expression of the GM-CSF gene as it does the IL-2 gene.

Base Sequence↗

PubMed1993

Phosphorylation of annexin XI (CAP-50) in SR-3Y1 cells.

Annexin XI (CAP-50) is a probable target protein of calcyclin. Being different from other annexins, annexin XI localizes mainly in nuclei of cultured fibroblasts. In rat embryonic fibroblasts transformed by Rous sarcoma virus oncogene, SR-3Y1 cells, phosphorylation of annexin XI was increased on both serine and threonine residues (Ser < Thr), compared with findings in control 3Y1 cells. The amount of phosphorylated annexin XI was approximately 8.5% of the total cellular annexin XI and the phosphorylated annexin XI migrated slightly slower on SDS-polyacrylamide gel electrophoresis than did the non-phosphorylated form of annexin XI. Phosphorylated annexin XI was recovered in the cytoplasmic fraction and did not bind to phosphatidylserine vesicle in the presence of high Ca2+ (over 1 mM). Annexin XI was phosphorylated by mitogen-activated protein (MAP) kinase, which was reported to be activated in v-src-transformed fibroblast (Gupta, S. K., Gallego, C. Johnson, G.L. and Heasley, L.E. (1992) J. Biol. Chem. 267, 7987-7990), on both serine and threonine residues (Ser >> Thr) in vitro. Comparative phosphopeptide mappings analyzed by reverse-phase high performance liquid chromatography suggested that the sites phosphorylated in situ in SR-3Y1 cells are distinct from the sites by MAP kinase. Annexin XI phosphorylated by MAP kinase still possessed the ability to bind to phosphatidylserine vesicle. These results suggest that annexin XI is a substrate for some Ser/Thr kinase(s) which is activated in v-src-transformed cells and that the phosphorylation may regulate the function of annexin XI in living cells.

Animals↗

PubMed1993

Calcyclin-binding site located on the NH2-terminal domain of rabbit CAP-50 (annexin XI): functional expression of CAP-50 in Escherichia coli.

CAP-50 (annexin XI) is a member of annexin family proteins originally identified and characterized as a target protein for calcyclin (H. Tokumitsu et al. (1992) J. Biol. Chem. 267, 8919-8924). In the present work, the calcyclin-binding site of CAP-50 was determined by proteolytic study and by using various deletion mutants expressed in Escherichia coli. The 43-kDa fragment of CAP-50 digested with Staphylococcus aureus V8 protease did not bind to calcyclin in the presence of Ca2+. CAP-50 fusion proteins, including various NH2-terminal deletion mutants were expressed in E. coli using rabbit CAP-50 cDNA and the calcyclin-binding potential was examined using the 125I-calcyclin gel overlay method and coprecipitation with phosphatidylserine-containing vesicles in the presence of Ca2+. All recombinant protein carried the potential for Ca(2+)-dependent phospholipid binding, due to the presence of the COOH-terminal domain (core domain). Calcyclin-binding experiments showed that CAP-50 molecules lacking the NH2-terminal 26 residues retain binding potential for calcyclin; however, deletion of an additional 26 amino acids from the NH2 terminus abolishes specific calcyclin binding. These observations suggest that the calcyclin-binding site is located on the NH2-terminal region of CAP-50, probably adjacent to or within the region from Tyr27 to Leu52.

Animals↗

PubMed1993

The granulocyte-macrophage colony-stimulating factor promoter cis-acting element CLE0 mediates induction signals in T cells and is recognized by factors related to AP1 and NFAT.

Expression of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene in T cells is activated by the combination of phorbol ester (phorbol myristate acetate) and calcium ionophore (A23187), which mimic antigen stimulation through the T-cell receptor. We have previously shown that a fragment containing bp -95 to +27 of the mouse GM-CSF promoter can confer inducibility to reporter genes in the human Jurkat T-cell line. Here we use an in vitro transcription system to demonstrate that a cis-acting element (positions -54 to -40), referred to as CLE0, is a target for the induction signals. We observed induction with templates containing intact CLE0 but not with templates with deleted or mutated CLE0. We also observed that two distinct signals were required for the stimulation through CLE0, since only extracts from cells treated with both phorbol myristate acetate and A23187 supported optimal induction. Stimulation probably was mediated by CLE0-binding proteins because depletion of these proteins specifically reduced GM-CSF transcription. One of the binding factors possessed biochemical and immunological features identical to those of the transcription factor AP1. Another factor resembled the T-cell-specific factor NFAT. The characteristics of these two factors are consistent with their involvement in GM-CSF induction. The presence of CLE0-like elements in the promoters of interleukin-3 (IL-3), IL-4, IL-5, GM-CSF, and NFAT sites in the IL-2 promoter suggests that the factors we detected, or related factors that recognize these sites, may account for the coordinate induction of these genes during T-cell activation.

Animals↗

PubMed1993

Design and preparation of ethyl cellulose microcapsules of gadopentetate dimeglumine for neutron-capture therapy using the Wurster process.

Microcapsules of hygroscopic, highly water-soluble gadopentetate dimeglumine (Gd-DTPA-DM) for use in preliminary in vivo experiments for neutron-capture therapy were designed. They were prepared with such properties as a particle size small enough to be suspended and injected through a syringe, a negligible release of Gd-DTPA-DM, and a high drug content by means of the Wurster process, a spray coating method using a spouted bed with a draft tube. They were composed of lactose cores of 53-63 microm, an undercoat of ethyl cellulose (EC) and polyvinylpyrrolidone (PVP), a drug-layer of Gd-DTPA-DM, EC and PVP, a waterproof coat and a release-sustaining overcoat of EC and cholesterol (1:1), and a surface treated with hydrogenated egg lecithin. By curing at 110 degrees C for 30 min after mixing with 20% pulverized mannitol powder, the 20% overcoating suppressed the release of Gd-DTPA-DM from 75-106 microm microcapsules to less than 10% for the first 20 min, which was the period required to prepare a suspension, inject it and irradiate the neutron. The microcapsules could be used to confirm that the intracellular presence of Gd is not critical in gadolinium neutron-capture therapy.

Cellulose↗