Biomedical subjects

Tohru Mochizuki

Publications and source records attributed to Tohru Mochizuki.

6 recordsLinked to original sources

PubMed2003

Apelin, a new enteric peptide: localization in the gastrointestinal tract, ontogeny, and stimulation of gastric cell proliferation and of cholecystokinin secretion.

Apelin is a recently discovered peptide that is the endogenous ligand for the APJ receptor. The aim of this study was to characterize apelin expression (mRNA levels) in the rat gastrointestinal tract and pancreas, to localize distribution of apelin peptide-containing cells in the stomach by immunohistochemistry, and to characterize the ontogeny of gastric apelin expression and peptide and the influence of apelin on gastric cell proliferation in vitro. Additionally, the effect of apelin on cholecystokinin (CCK) secretion and the involvement of MAPK, protein kinase C, and changes in intracellular Ca(2+) in apelin-induced CCK secretion in vitro were examined. Northern analysis showed a maximal apelin expression in the stomach with a lower expression level in the intestine. Apelin expression was not detected in the pancreas. Immunohistochemistry revealed abundant apelin-positive cells in the glandular epithelium of the stomach. The ontogeny study showed a higher apelin expression in the fetal and postnatal rat stomachs when compared with the adult stomach. In contrast to apelin expression, apelin peptide was not detected in the rat stomach until 20 d of age and then increased progressively with age. Apelin was shown to stimulate gastric cell proliferation in vitro. Apelin also stimulated CCK secretion from a murine enteroendocrine cell line (STC-1); apelin-stimulated CCK secretion is mediated through MAPK but not by intracellular Ca(2+) signaling. Together, these data indicate that apelin is an important new stomach peptide with a potential physiological role in the gastrointestinal tract.

Animals↗

PubMed2003

Regional concentration and chromatographic characterization of pituitary adenylate cyclase-activating polypeptide (PACAP) in the brain of the bullfrog, Rana catesbeiana.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a regulatory neuropeptide which functions as a hypothalamic factor for pituitary hormone release, and as a neurotransmitter, neuromodulator and neurotrophic factor in both frogs and mammals. This study examined the quantitative distribution and chromatographic characterization of immunoreactive PACAP in the central nervous system (CNS) of the bullfrog, Rana catesbeiana, using an enzyme immunoassay (EIA), named avidin-biotin complex detectable EIA for PACAP, and high-performance liquid chromatographic (HPLC) analysis. The brain of adult bullfrogs contained relatively high levels of immunoreactive PACAP (344.63 pmol/g wet weight of tissue). The average concentrations of immunoreactive PACAP in the regions of the telencephalon, diencephalon, tectum, cerebellum, rhombencephalon, and spinal cord were 213.84, 767.14, 524.94, 192.71, 237.67, and 362.04 pmol/g wet weight of tissue, respectively. The concentrations of immunoreactive PACAP increased with the brain development during metamorphosis, and the concentration of immunoreactive PACAP in the brain of tadpoles at the end of metamorphosis was approximately 200 pmol/g wet weight of tissue. The predominant form of immunoreactive PACAP in the CNS of adult and tadpole was eluted closely with synthetic PACAP38, but another smaller immunoreactivity also appeared in a the fraction, which corresponded to the retention time of synthetic PACAP27, as analyzed by reverse-phase HPLC.

Amino Acid Sequence↗

PubMed2002

Identification of HLA-A24-restricted CTL epitope encoded by the matrix protein pp65 of human cytomegalovirus.

The activation of a specific cellular immune response against human cytomegalovirus (CMV) is an important key factor to solving CMV infection after bone marrow transplantation (BMT). In the present study, our purpose was to identify the HLA-A24-restricted cytotoxic T cell (CTL) epitope from the CMV immunogenic matrix protein pp65. We selected five CMV pp65 peptides with HLA-A24 binding motif from the HLA peptide binding predictions web site. Peptide binding assay was performed using biotinylated HLA-A24-restricted MAGE-1 peptide as a reference peptide and transporter associated with antigen processing (TAP)-deficient T2-A24 cells expressing high level of HLA-A24 protein as target cells. After co-incubation of biotinylated MAGE-1 and titrated amounts of competitor peptides with T2-A24 cells, the binding of each peptide was analyzed on a flow cytometer. Peptide binding assay showed that three out of five peptides derived from CMV pp65 bound to T2-A24 cells with various affinity levels. CTL induction assay using peptide-pulsed DC derived from eight HLA-A24(+) donors revealed that the peptide (QYDPVAALF) with the highest affinity was able to elicit potent CTLs which killed peptide-pulsed TISI cells. These CTLs were found to show the killing activity against human fibroblast cells transduced with both HLA-A*2402 and CMV pp65 cDNAs, and CMV-infected HLA-A24(+) fibroblast cells. These results suggested that the peptide (QYDPVAALF) is one of HLA-A24-restricted CTL epitope derived from CMV pp65 protein and may be of therapeutic value in peptide-based vaccines against CMV infection in BMT patients.

Antibodies, Monoclonal↗

PubMed2002

A newly developed enzyme-immunoassay for measuring the tissue contents of PACAP in fish.

We have developed a novel and easy enzyme-immunoassay (EIA) for pituitary adenylate cyclase-activating polypeptide (PACAP). We used it to determine immunoreactive PACAP levels in the central nervous system (CNS) and peripheral tissues of two fishes, a teleost (the stargazer) and an elasmobranch (a stingray). An antiserum was raised in a white rabbit immunized with a conjugate of synthetic stargazer PACAP27 plus keyhole limpet hemocyanin. The EIA system used an antiserum/biotin-labeled PACAP/avidin/biotin-conjugated enzyme complex, and a double antibody method was used to precipitate the immune complexes. We call the system the avidin-biotin complex detectable EIA (ABCDEIA) for PACAP. ABCDEIA with biotin-labeled PACAP27 detected only PACAP27, recognizing neither the longer forms of PACAP nor any other peptides. PACAPs with 27, 38, and 44 residues cross-reacted in another ABCDEIA with biotin-labeled PACAP38 or PACAP44. Whole brains of both fishes contained much higher levels of PACAP, 6-30 times as high as the levels in the mammalian brain, but unexpectedly, no immunoreactive PACAP27 was found in any CNS or peripheral tissue in either fish. The gastrointestinal tracts of fish also contained lower, but significant amounts of PACAP.

Amino Acid Sequence↗

PubMed2002

[Damage control for thoracic injuries].

A critically injured chest trauma patient showing profound shock or cardiac arrest en route to the trauma center or in the emergency room sometimes requires emergency room thoracotomy and definitive repair. In some patients damage control must be performed because of the appearance of the deadly triad of hypothermia, acidosis, and coagulopathy. Indications for damage control are believed to be body temperature < 34 degrees C, pH < 7.2, and clinically uncontrollable bleeding. The strategy for damage control consists of three steps: step 1, rapid control of hemorrhaging and abbreviated surgery in the ER or OR; step 2, correction of hypothermia, acidosis, and coagulopathy and reevaluation of the injuries in the intensive care unit; and step 3, definitive surgery in the OR. Damage control procedures for chest injuries include aortic cross-clamping, hilar clamping, major vessel ligation, pulmonary tractotomy, simultaneously stapled pneumonectomy or lobectomy, cardiac stapling, balloon catheter tamponade, temporary intraluminal shunt, towel packing, towel clip closure, single en masse closure of the chest wall, etc. Every surgeon responsible for treating critical chest trauma patients should have knowledge of damage control and also be familiar with the techniques.

Acidosis↗

PubMedDate not supplied

Cytotoxic T cell induction against human malignant melanoma cells using HLA-A24-restricted melanoma peptide cocktail.

Many human leukocyte antigen (HLA)-class I (mainly A*0201)-restricted peptide-specific cytotoxic T cells (CTLs) have been derived from peripheral blood lymphocytes (PBLs) of melanoma patients. However, few studies regarding HLA-A*2402-restricted melanoma-associated peptides have been performed, because HLA-A24 is not a common allele in Caucasians. In this study, we investigated the specific CTL-inducing activity of 5 HLA-A*2402-restricted peptides derived from gp100, tyrosinase, MAGE1, MAGE2 and MAGE3. A CTL induction culture was performed using PBLs and cultured dendritic cell (DC) pulsed with HLA-A*2402-restricted melanoma peptide cocktail. The CTLs derived from volunteers killed the A24 peptide-pulsed TISI cells and even HLA-A*2402-positive melanoma cells, but not HLA-A*0201-positive cells. IFN-gamma levels produced by the melanoma patients' CTLs were obviously low in each peptide group compared with those produced by the volunteers' CTLs, which indicated the presence of immunosuppressive factors in metastatic melanoma. These results suggested that polyvalent immunotherapy using multiple epitopes from melanoma antigens might be a better way of improving the efficacy of treatment.

Antigens, Neoplasm↗