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Biomedical subjects

H Takasu

Publications and source records attributed to H Takasu.

At least 19 recordsLinked to original sources
PubMed2001

Interferon-alpha: an effective adjuvant for peptide-based cytotoxic T-cell vaccines.

An important issue for developing a vaccine therapy for human malignancy is identifying adjuvants that can elicit T-cell responses to peptides. The present study evaluates interferon-alpha (IFN-alpha) as a vaccine adjuvant. C57BL/6 mice were immunized subcutaneously with peptide derived from influenza virus (Flu) either with or without IFN-alpha using different vaccine formulations. IFN-alpha significantly enhanced cytotoxic T lymphocytes (CTL) induction in mice immunized with Flu peptide in incomplete Freund's adjuvant (IFA). Flu peptide administered continuously for 3 days by osmotic pump with IFN-alpha could elicit CTL induction, whereas either Flu peptide or IFN-alpha alone was non immunogenic. Furthermore, injection of the liquid formation of Flu peptide with IFN-alpha in phosphate-buffered saline (PBS) did not elicit CTL induction. These results suggest that the continuous administration of peptide and local delivery of IFN-alpha are important for efficient CTL induction, and that IFN-alpha is an effective adjuvant for peptide-based vaccines.

Adjuvants, Immunologic↗
PubMed2000

Spitz nevus on the palmar surface.

Relatively little is known about the incidence of Spitz nevus on palmar surfaces. This report places a case study in the context of the Japanese literature regarding the occurrence of Spitz nevus on palmar surfaces. Although the proportion of palms and soles in relation to the body surface is about 5%, the incidence of the Spitz nevus was 2%. The mean age at onset was 17.8 years, and all 4 cases were women. The clinical features were a black macule or flatly elevated small modules. The size of the lesions was relatively small, extending from 3.5 mm to 8.0 mm. Although the backs of the hands and insteps have almost the same area as the palms and soles, the incidence of onset in these regions was 6.3% (13 cases). We thus concluded that Spitz nevus tends to be rare on palms and soles.

Child↗
PubMed2000

Mouse homologue of the human SART3 gene encoding tumor-rejection antigen.

We recently isolated a human SART3 (hSART3) gene encoding a tumor-rejection antigen recognized by HLA-A2402-restricted cytotoxic T lymphocytes (CTLs). The hSART3 was also found to exist as an RNA-binding nuclear protein of unknown biological function. In this study, we cloned and analyzed the homologous mouse SART3 (mSART3) gene in order to understand better the function of hSART3, and to aid in establishing animal models of specific immunotherapy. The cloned 3586-bp cDNA encoded a 962-amino acid polypeptide with high homology to hSART3 (80% or 86% identity at the nucleotide or protein level, respectively). Nonapeptides recognized by the HLA-A2402-restricted CTLs and all of the RNA-binding motifs were conserved between hSART3 and mSART3. The mSART3 mRNA was ubiquitously expressed in normal tissues, with low level expression in the liver, heart, and skeletal muscle. It was widely expressed in various organs from as early as day 7 of gestation. mSART3 was mapped to chromosome 5, a syntenic region for human chromosome 12q23-24, and its genomic DNA extended over 28-kb and consisted of 19 exons. This information should be important for studies of the biological functions of the SART3 protein and for the establishment of animal models of specific cancer immunotherapy.

Amino Acid Sequence↗
PubMed1999

Amino-terminal modifications of human parathyroid hormone (PTH) selectively alter phospholipase C signaling via the type 1 PTH receptor: implications for design of signal-specific PTH ligands.

Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) activate the PTH/PTHrP receptor to trigger parallel increases in adenylyl cyclase (AC) and phospholipase C (PLC). The amino (N)-terminal region of PTH-(1-34) is essential for AC activation. Ligand domains required for activation of PLC, PKC, and other effectors have been less well-defined, although some studies in rodent systems have identified a core region [hPTH-(29-32)] involved in PKC activation. To determine the critical ligand domain(s) for PLC activation, a series of truncated hPTH-(1-34) analogues were assessed using LLC-PK1 cells that stably express abundant transfected human or rat PTH/PTHrP receptors. Phospholipase C signaling and ligand-binding affinity were reduced by carboxyl (C)-terminal truncation of hPTH-(1-34) but were coordinately restored when a binding-enhancing substitution (Glu(19) --> Arg(19)) was placed within hPTH-(1-28), the shortest hPTH peptide that could fully activate both AC and PLC. Phospholipase C, but not AC, activity was reduced by substituting Gly(1) for Ser(1) in hPTH-(1-34) and was eliminated entirely by removing either residue 1 or the alpha-amino group alone. These changes did not alter binding affinity. These findings led to design of an analogue, [Gly(1),Arg(19)]hPTH-(1-28), that was markedly signal-selective, with full AC but no PLC activity. Thus, the extreme N-terminus of hPTH constitutes a critical activation domain for coupling to PLC. The C-terminal region, especially hPTH-(28-31), contributes to PLC activation through effects upon receptor binding but is not required for full PLC activation. The N-terminal determinants of AC and PLC activation in hPTH-(1-34) overlap but are not identical, as subtle modifications in this region may dissociate activation of these two effectors. The [Gly(1),Arg(19)]hPTH-(1-28) analogue, in particular, should prove useful in dissociating AC- from PLC-dependent actions of PTH.

Adenylyl Cyclases↗
PubMed1999

Identification of a gene coding for a protein possessing shared tumor epitopes capable of inducing HLA-A24-restricted cytotoxic T lymphocytes in cancer patients.

Genes encoding tumor epitopes that are capable of inducing CTLs against adenocarcinomas and squamous cell carcinomas, two major human cancers histologically observed in various organs, have rarely been identified. Here, we report a new gene from cDNA of esophageal cancer cells that encodes a shared tumor antigen recognized by HLA-A2402-restricted and tumor-specific CTLs. The sequence of this gene is almost identical to that of the KIAA0156 gene, which has been registered in GenBank with an unknown function. This gene encodes a Mr 140,000 protein that is expressed in the nucleus of all of the malignant tumor cell lines tested and the majority of cancer tissues with various histologies, including squamous cell carcinomas, adenocarcinomas, melanomas, and leukemia cells. However, this protein was undetectable in the nucleus of any cell lines of nonmalignant cells or normal tissues, except for the testis. Furthermore, this protein was expressed in the cytosol of all of the proliferating cells, including normal cells and malignant cells, but not in normal tissues, except for the testis and fetal liver. Two peptides of this protein were recognized by HLA-A2402-restricted CTLs and were able to induce HLA-A24-restricted and tumor-specific CTLs from peripheral blood mononuclear cells of most of HLA-A24+ cancer patients tested, but not from peripheral blood mononuclear cells of any healthy donors. These peptides may be useful in specific immunotherapy for HLA-A24+ cancer patients with various histological types.

Antigens, Neoplasm↗
PubMed1999

Dual signaling and ligand selectivity of the human PTH/PTHrP receptor.

Parathyroid hormone (PTH) activates PTH/PTH-related peptide-related receptors (PTHRs) to stimulate both adenylyl cyclase (AC) and phospholipase C (PLC). How these parallel signals mediate specific cellular and tissue responses to PTH, such as the complex anabolic versus catabolic actions of PTH on bone, remains unsettled. Previous studies of PTHR signaling and function employed mainly rodent or other cell lines that express endogenous PTHRs and, possibly, alternate species of PTH receptors. To preclude confounding effects of such receptors, we stably expressed recombinant human PTHRs (hPTHRs) at different levels of surface density in LLC-PK1 porcine renal epithelial cells that lack endogenous PTH responsiveness. hPTH(1-34) induced concentration-dependent activation of both AC and PLC via transfected hPTHRs. Maximal intensity of each signal increased with receptor density, but more hPTHRs were required for PLC than for AC activation. Coupling to AC was saturated at receptor densities too low to detect sustained PLC activation. hPTH(3-34), found by others to be a PLC/protein kinase C (PKC)-selective peptide in rat cells, did not activate PLC via human (or rat) PTHRs under conditions (1 microM peptide, 106 hPTHRs/cell) where hPTH(1-34) stimulated PLC severalfold. Other cellular responses that require PKC activation in these cells, such as sodium-dependent phosphate transport and cAMP-independent secretion of plasminogen activator, were induced by PTH(1-34) but not by hPTH(3-34) or hPTH(7-34). We conclude that amino-truncated PTH analogs reported to activate PKC cannot directly activate phosphatidylinositol-specific PLC via the human or rat PTHR and therefore that PTH receptors may access alternate, PLC-independent pathways of PKC activation in some target cells. The relative intensity of AC and PLC signaling via the hPTHR may be strongly regulated by changes in its surface expression.

Adenylyl Cyclases↗
PubMed1998

A gene encoding antigenic peptides of human squamous cell carcinoma recognized by cytotoxic T lymphocytes.

Except for melanomas, tumor antigens recognized by cytotoxic T lymphocytes (CTLs) are yet unidentified. We have identified a gene encoding antigenic peptides of human squamous cell carcinomas (SCCs) recognized by human histocompatibility leukocyte antigens (HLA)- A2601-restricted CTLs. This gene showed no similarity to known sequences, and encoded two (125- and 43-kilodalton [kD]) proteins. The 125-kD protein with the leucine zipper motif was expressed in the nucleus of the majority of proliferating cells tested, including normal and malignant cells. The 43-kD protein was expressed in the cytosol of most SCCs from various organs and half of lung adenocarcinomas, but was not expressed in other cancers nor in a panel of normal tissues. The three nonapeptides shared by the two proteins were recognized by the KE4 CTLs, and one of the peptides induced in vitro from peripheral blood mononuclear cells (PBMCs) the CTLs restricted to the autologous tumor cells. The 43-kD protein and this nonapeptide (KGSGKMKTE) may be useful for the specific immunotherapy of HLA-A2601(+) epithelial cancer patients.

Amino Acid Sequence↗
PubMed1998

The analysis of mRNA expression of cytokines from skin lesions in Churg-Strauss syndrome.

We report our recent clinical experience with a patient suffering from Churg-Strauss syndrome and the results of our investigation into the mRNA expression of cytokines in the patient's lesions as well as in the frozen sections from a previous patient. In both cases, blood IgG was at a high level. Cytokine mRNA expression differed according to the degree of cellular infiltration. In the presence of marked infiltration, counteracting Th1 and Th2 cytokines were simultaneously detected; the former included IL-12 and IFN-gamma, and the latter, IL-6 and IL-10. The concurrence of both types of cytokine could be attributed to several factors. For example, IL-6 is involved through some mechanism in the formation of immune complexes by IgG, and IL-12 and IFN-gamma appeared to participate in the development of granuloma. These suppositions support the suggested immunological etiology of the disease. It is also inferred that the dominance of one of the two types of cytokines depends on the clinical phase of the disease.

Biomarkers↗
PubMed1998

Sequence analysis of genes encoding rodent homologues of the human tumor-rejection antigen SART-1.

Human SART-1 (hSART-1) gene encodes a 125 kD protein with a leucine-zipper motif expressed in the nucleus of all proliferating cells, and a 43 kD protein expressed in the cytosol of most epithelial cancers. In this study, two rodent genes (rSART-1 and mSART-1) homologous to hSART-1 were cloned from cDNA libraries of murine brain and a rat tumor cell line, respectively. mSART-1 and rSART-1 were highly homologous to hSART-1 with 86% and 84% identity at the nucleotide level, and 95% and 91% at the protein level, respectively. The leucine zipper domain and two basic amino acid portions that bind DNA, as well as peptide sequences recognized by human cytotoxic T lymphocytes (CTLs), were all conserved in these rodent genes. Nuclear protein homologous to the 125 kD hSART-1(800) protein, but not to the 43 kD cytosol SART-1(259) protein, was detectable with specific antibody in the nuclear fractions of rodent tumor cell lines, and normal rodent fetal liver and testis. These rodent genes should be a novel tool for studies on the biological roles of the SART-1 gene, and also in the construction of animal models of specific immunotherapy using SART-1 gene products.

Amino Acid Sequence↗
PubMed1998

Cathepsin D expression in skin metastasis of breast cancer.

Cathepsin D, an aspartic proteinase, correlates with invasion and metastasis in breast cancer and with poor prognosis. In the present study, we examined the immunohistological expression of cathepsin D in both primary (5 cases) and skin-metastatic breast cancers (13 cases) and compared it to those in gastric (2 cases) and lung (4 cases), and primary eccrine cancers (3 cases). All breast and gastric cancers were adenocarcinomas. The 2 gastric cancers were poorly differentiated, while the 4 lung cancers consisted of 2 poorly differentiated adenocarcinomas, 1 poorly differentiated large cell carcinoma, and 1 moderately to poorly differentiated squamous cell carcinoma. We also surveyed the immunohistological distribution of cathepsin B, carcinoembryonic antigen, gross cystic disease fluid protein-15, c-erbB-2, and estrogen receptor. In almost all breast cancer samples, the cancer cells demonstrated strong expression of cathepsin D in the cytoplasm, but weak staining patterns with other antibodies. Gastric and lung cancer cells did not respond with cathepsin D (except one metastatic lung cancer) or the other immunohistological markers. Since cathepsin D is strongly expressed in primary and metastatic lesions of breast cancer, cathepsin D could be useful as an adjunct to a panel of immunohistochemical stains in determining the primary site of origin of metastatic cancer in the skin.

Adenocarcinoma↗
PubMed1998

Type-1 parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptors activate phospholipase C in response to carboxyl-truncated analogs of PTH(1-34).

The carboxyl(C)-truncated human (h) PTH (hPTH) analog hPTH(1-31), which activates adenylyl cyclase (AC), but not protein kinase C, in rat osteosarcoma cells, exerts an anabolic effect on rat bone in vivo similar to that of hPTH(1-34). It has been proposed, therefore, that this action of PTH(1-34) is mediated exclusively by stimulation of AC via the rat type-1 PTH/PTH-related peptide (PTHrP) receptor (PTH1R). To determine whether this selective signaling pattern also might be a property of the hPTH1R, we studied signal transduction via heterologously expressed hPTH1Rs in response to activation by hPTH(1-34), hPTH(1-31), and a C-truncated analog that does not increase rat bone mass in vivo, hPTH(1-30). In porcine LLC-PK1 cells that stably expressed recombinant hPTH1Rs, these three peptides activated AC identically (EC50 = 1-2 nM). In cells with comparable expression of rat PTH1Rs, AC activation by hPTH(1-34) and hPTH(1-31) again was identical, whereas full activation by hPTH(1-30) required higher concentrations (EC50 = 10 nM vs. 1 nM). Surprisingly, hPTH(1-31) fully stimulated phospholipase C (PLC), via both species of PTH1Rs, with potency that was similar (hPTH1Rs) or slightly reduced (rat PTH1Rs), relative to that of hPTH(1-34). hPTH(1-30), however, was 5-fold less potent than hPTH(1-34) in activating PLC via hPTH1Rs and showed weak and only partial activity via the rat PTH1R. Comparable results were obtained when human and rat PTH1Rs were transiently expressed heterologously in COS-7 cells or homologously in HEK 293 and UMR 106-01 cells, respectively. Binding affinities of these C-truncated peptides to human and rat PTH1Rs were concordant with their relative potencies in activating PLC. We conclude that hPTH(1-31) and, to a lesser extent, hPTH(1-30) can activate PLC, as well as AC, via both rat and human PTH1Rs. Accordingly, a role for PLC activation in the anabolic action of PTH in vivo cannot be excluded.

Animals↗
PubMed1997

HLA class I-restricted and tumor-specific cytotoxic T lymphocytes from metastatic lymph nodes of esophageal cancers.

This paper investigates the presence of HLA class I-restricted and tumor-specific cytotoxic T lymphocytes (CTL) in tumor sites of esophageal cancers. Five CTL lines were established from the metastatic lymph nodes or pleural effusion by incubation with interleukin-2 of tumor-infiltrating lymphocytes: cases 1 and 5, HLA-A26- and HLA-A33-restricted and squamous cell carcinoma (SCC)-specific CTL; case 2, HLA-Cw0102-restricted and esophageal SCC-specific CTL; case 3, HLA-A24- and HLA-A26-restricted CTL recognizing histologically different tumor cells; and case 4, HLA-A26-restricted and esophageal SCC-specific CTL. These results suggest the existence of HLA class I-restricted and tumor-specific CTL in metastatic esophageal SCC.

Aged↗
PubMed1996

The 69-84 amino acid region of the parathyroid hormone molecule is essential for the interaction of the hormone with the binding sites with carboxyl-terminal specificity.

We evaluated the competitive inhibitory effect of intact PTH, the amino-terminal PTH(1-34) fragment, and a series of truncated carboxyl-terminal PTH fragments on the binding of internally 35S-labeled human PTH(1-84) ([35S]hPTH(1-84)) to osteoblastic cells (ROS 17/2.8), in order to identify the minimum and critical elements within the PTH molecule for the interaction with the binding sites specific for the carboxyl-terminal region of the hormone. When the amino-terminal region of the PTH molecule was truncated stepwise, hPTH(35-84), hPTH(53-84) and hPTH(69-84), but not hPTH(70-84), significantly inhibited the [35S]hPTH(1-84) binding. On the other hand, the simple deletion of the carboxyl-terminal glutamine at position 84 of hPTH(53-84) [hPTH(53-83)] resulted in blunting the inhibitory effect of the peptide on the [35S]hPTH(1-84) binding. Furthermore, hPTH(35-84), hPTH(53-84) and hPTH(69-84), but not hPTH(70-84) nor hPTH(53-83), augmented the inhibitory effect of the amino-terminal PTH fragment [hPTH(1-34)] on the [35S]hPTH(1-84) binding. Of special interest was that the combination of hPTH(1-34) and hPTH(35-84) reproduced the inhibitory effect of unlabeled hPTH(1-84) on the [35S]hPTH(1-84) binding, on an equimolar basis. The 69-84 region of the PTH molecule thus appears to be crucial for binding to the carboxyl-terminal specific binding sites for PTH in osteoblasts. The interaction of the amino-terminal and carboxyl-terminal regions of a PTH molecule with their own respective binding sites seemed to occur in a fairly independent manner.

Alkaline Phosphatase↗
PubMed1995

Peptide mapping of recombinant human parathyroid hormone by enzymatic digestion and subsequent fast-atom bombardment mass spectrometry.

Peptide maps of recombinant human parathyroid hormone (rhPTH) were determined by both trypsin and V-8 protease digestion with subsequent fast-atom bombardment mass spectrometry (FAB-MS). Coverage of the sequence was 85% when using trypsin and 90% when using V-8 protease. Five rhPTH variants that were recombinantly produced as models of Asn deamidated type degradation products were measured, and molecular weight differences between their respective deamidated peptide fragments were completely detected. In the V-8 protease digests of some variants, characteristic peptide ions caused by the deamidation were observed and this greatly facilitated the assignment and recognition of the deamidated position. Our data suggest that FAB-mapping of rhPTH via the protease digestion methods used, appears to have great potential for structural investigations of the peptide.

Amino Acid Sequence↗
PubMed1995

Activity of artificial mutant variants of human growth hormone changes in charged residues around 62-67.

Our previous work has shown that the amino acid residues around 62-67 located in the connecting loop between helix I and II of human growth hormone (hGH) are important in eliciting the differentiation of preadipose 3T3-F442A cells to adipocytes. In this study, we evaluated the role of the charged residues around 62-67 in receptor binding and biological activity. Eight artificial mutant variants of hGH were prepared in Escherichia coli by site-directed mutagenesis. Replacement of Arg64 with Tyr (R64Y variant) resulted in a significant loss of binding to the somatogenic receptors on 3T3-F442A cells, but retained full adipose conversion activity on these cells. Replacement of Arg64 with Glu (R64E) produced a considerable loss in receptor binding and a significant loss in biological activity. hGH variants in which either Glu65 or Glu66 was replaced with Asp (E65D and E66D) and with Gln (E65Q and E66Q) showed a slight loss in binding activity and retained almost a full adipogenic activity. An E65P variant (replacement of Glu65 with Pro) possessed the same binding activity as hGH, although it failed to induce full biological activity. The insertion of Ala between Asn63 and Arg64 (63NAR) caused a marked loss in both activities. These results indicate that the positively charged Arg64 is important for receptor binding and thereby in eliciting the biological activity of hGH, while negatively charged Glu65 and Glu66 are less important. In addition, our findings confirm that the conformation and size of the loop region around Arg64 is important for the adipose conversion activity of hGH.

Adipose Tissue↗
PubMed1993

[Primary non-Hodgkin lymphoma of the prostate: a case report].

A 24-year-old man presented with gross hematuria and pain on micturition. Cystoscopically the prostatic urethra appeared to be pale, edematous and partly elevated mucosa, from which multiple biopsy specimens were taken by TUR-P. A pathological diagnosis of malignant lymphoma (diffuse and large-cell type, according to the LSG classification: B-cell origin according to immunohistochemistry) was established. The results of the physical examination and imaging studies were compatible with the diagnosis of primary lymphoma of the prostate. The patient underwent a combination chemotherapy consisting of vincristine, cyclophosphamide, adriamycin and prednisolone. After completion of 6 courses of chemotherapy over 7 months, another TUR biopsy of the prostate confirmed complete remission. Now, 1 year after completion of chemotherapy, he remains free of the disease. To our knowledge, this is the 21st clinical case of lymphoma of the prostate ever reported in the Japanese literature.

Adult↗