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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 19 recordsLinked to original sources
PubMed1995

Protective immune responses induced by secretion of a chimeric soluble protein from a recombinant Mycobacterium bovis bacillus Calmette-Guérin vector candidate vaccine for human immunodeficiency virus type 1 in small animals.

A recombinant Mycobacterium bovis bacillus Calmette-Guérin (BCG) vector-based vaccine that secretes the V3 principal neutralizing epitope of human immunodeficiency virus (HIV) could induce immune response to the epitope and prevent the viral infection. By using the Japanese consensus sequence of HIV-1, we successfully constructed chimeric protein secretion vectors by selecting an appropriate insertion site of a carrier protein and established the principal neutralizing determinant (PND)-peptide secretion system in BCG. The recombinant BCG (rBCG)-inoculated guinea pigs were initially screened by delayed-type hypersensitivity (DTH) skin reactions to the PND peptide, followed by passive transfer of the DTH by the systemic route. Further, immunization of mice with the rBCG resulted in induction of cytotoxic T lymphocytes. The guinea pig immune antisera showed elevated titers to the PND peptide and neutralized HIVMN, and administration of serum IgG from the vaccinated guinea pigs was effective in completely blocking the HIV infection in thymus/liver transplanted severe combined immunodeficiency (SCID)/hu or SCID/PBL mice. In addition, the immune serum IgG was shown to neutralize primary field isolates of HIV that match the neutralizing sequence motif by a peripheral blood mononuclear cell-based virus neutralization assay. The data support the idea that the antigen-secreting rBCG system can be used as a tool for development of HIV vaccines.

AIDS Vaccines↗
PubMed1995

TTX-resistant Ca2+ oscillation in cultured hypothalamus: similarity to the mammalian circadian pacemaker.

Dissociated cultures of rat hypothalamic cells showed spontaneous oscillations in intracellular Ca2+ with periods of 5-8 s (ultradian rhythm). Replacement of H2O by deuterium oxide in the culture medium lengthened the period of this oscillation, while tetrodotoxin did not inhibit the deuterium oxide sensitive Ca2+ oscillation. Since these characteristics resemble those of the mammalian circadian pacemaker, the ultradian Ca2+ rhythms may be involved in the circadian rhythm or have a similar rhythm generation mechanism. The gap junction inhibitor, halothane, stopped this oscillation. Gap junctions may be necessary in order to generate rhythmic oscillations.

Animals↗
PubMed1995

Characterization of measles viruses isolated after measles vaccination.

Seven measles virus (MV) strains were isolated from children who developed clinical signs of fever and rash 3-9 days after measles vaccination. The nucleotide sequence of the H gene, the molecular size of the H protein, the haemadsorption activity on African green monkey red blood cells, and antigenicity as determined by virus neutralization revealed that one strain was of the vaccine type and the remaining six were the wild virus type. Isolation of the virus directly from patients suspected of a vaccine-induced side-reaction and subsequent characterization of such isolated virus may be useful in differentiation between vaccine-induced side-reactions and natural measles.

Antibodies, Monoclonal↗
PubMed1995

Pharmacokinetics and biologic activities of human native and asialointerferon-beta s.

Glycoproteins are metabolized through an asialoglycoprotein metabolic pathway in vivo. They are desialylated and taken up by the liver via an asialoglycoprotein receptor. Fibroblast-derived natural human interferon-beta is a glycoprotein having a single asparagine-linked sugar chain. Although natural human interferon-beta may also be metabolized through this pathway, there is very little information about the biologic features of human asialointerferon-beta. We evaluated the pharmacokinetics and biologic activities of human native and asialointerferon-beta s. After intravenous administration to rabbits, human asialointerferon-beta was cleared from the blood circulation faster than the human native interferon-beta. More asialoprotein was distributed to the liver than the native type, but it induced less 2'5'-oligoadenylate synthetase. The human asialointerferon-beta had less activity than the human native interferon-beta on cell growth inhibition and 2'5'-oligoadenylate synthetase induction in Hep-G2 and HuH6 human hepatoblastoma cells. Southern blotting using a hepatitis B virus-transfected HuH6 cell line, HB611, revealed that the inhibition of hepatitis B virus DNA replication by the asialoprotein was weaker than that by the native protein. The results showed that the different effects exerted by the human native and asialointerferon-beta s may be a result of recognition of the sugar chains by rabbit hepatocytes or by human hepatoblastoma cells. The results also suggested that the terminal sialic acid of the sugar chains in natural human interferon-beta significantly affects its pharmacokinetics and biologic activities.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Synergistic effect of methionine-depleting total parenteral nutrition with 5-fluorouracil on human gastric cancer: a randomized, prospective clinical trial.

Methionine-depleting total parenteral nutrition (Met-depleting TPN), infusing AO-90 amino acid solution (lacking both L-methionine and L-cysteine) as a sole nitrogen source, showed synergistic effects with 5-fluorouracil (5-FU) in tumor-bearing rats and in clinical trials with gastrointestinal tract cancers. In this study, the effect of Met-depleting TPN with 5-FU upon thymidylate synthase (TS) activity was examined, and the histological effect of this treatment on human gastric cancer was evaluated. Fourteen preoperative advanced gastric cancer patients were divided randomly into two groups. Seven cases were given Met-depleting TPN for 7 days before surgery with continuous intravenous administration of 5-FU (500 mg/body per day; total 4.0 g/body) (AO-90 group). The other 7 received conventional L-methionine-containing TPN with 5-FU (control group). All patients underwent gastrectomy without complications due to these treatments. Resected materials were examined for TS kinetics, and the anti-cancer effect was also assessed histopathologically. The specimens in the AO-90 group showed marked degeneration of cancer, while almost no effect was seen in the control group. The free TS activity of carcinoma tissue in the AO-90 group was decreased and the TS inhibition rate was increased in comparison with the control group (P = 0.0165 and P = 0.0243, respectively). Met-depleting TPN appears to play a role as a biomodulator of 5-FU in human gastric cancer.

Aged↗
PubMed1995

[Serological diagnosis for human parvovirus B19 infection by an enzyme immunoassay kit with recombinant antigens synthesized in a baculovirus expression system].

Propagation of human parvovirus B19 (B19) in cell cultures are not applicable to the source of viral antigens for serological assays at present. Enzyme immunoassay (EIA) kits with recombinant B19 capsids by E. coli or baculovirus expression system have been developed. We tested serum samples from the patients with erythema infectiosum and aplastic crisis by EIA kit with recombinant antigens synthesized in a baculovirus expression system (Denka Seiken Co., Tokyo, Japan). The antigens used in the kit are self-assembled recombinants containing both VP-1 and VP-2 with the same proportion as found in native B19 capsids. B19 IgM is detected by antibody capture methods and IgG by indirect methods. All of the samples were positive for B19 DNA by nested PCR. Thirty-six (97%) of the 37 patients with erythema infectiosum and all (100%) of the 4 patients with aplastic crisis were positive for B19 IgM. The EIA kit with recombinant antigens synthesized in a baculovirus expression system has proved to be reliable and useful for the diagnosis of B19 infection.

Antibodies, Viral↗
PubMed1995

Purification and characterization of angiotensin I-converting enzyme inhibitors from sour milk.

The inhibitory activity of angiotensin I-converting enzyme in milk increased during fermentation with the Calpis sour milk starter containing Lactobacillus helveticus and Saccharomyces cerevisiae. Two kinds of peptides inhibitory to angiotensin I-converting enzyme were purified from the sour milk by using four-step HPLC. The amino acid sequences of these inhibitors were identified as Val-Pro-Pro and Ile-Pro-Pro. The concentrations of peptides providing 50% inhibition of angiotensin I-converting enzyme were 9 and 5 microM, respectively. Most of the inhibitory activity in sour milk was attributed to these two peptides.

Amino Acid Sequence↗
PubMed1995

[Histological effect and prognosis after preoperative chemotherapy in esophageal cancer].

Preoperative chemotherapy for esophageal cancer was performed and the toxic effects, post-operative complications, histological effects and survival time were evaluated. Toxic effects and post-operative complications were rare. The histological effect was evaluated according to the Guidelines for Clinical and pathologic studies on carcinoma of the esophagus by the Japanese Society for Esophageal Disease. A histological effect of more than Grade II was seen from 25 to 42.1%. A significant difference was seen in the Kaplan-Meier survival curves between the response group and the no response group (p < 0.05). If we perform preoperative chemotherapy for esophageal cancer only to responsive cases determined by chemosensitivity tests, the prognosis of advanced esophageal cancer may be improved.

Adult↗
PubMed1994

Immunosuppression to cardiac allografts and soluble antigens by anti-vascular cellular adhesion molecule-1 and anti-very late antigen-4 monoclonal antibodies.

Effective activation of T cells in immune responses depends on two signals, one from the CD3/TCR complex and another from accessory cell surface proteins. Very late Ag-4 (VLA-4) can exert a costimulatory function upon binding with vascular cellular adhesion molecule-1 (VCAM-1). We investigated the effects of mAbs against VCAM-1 and VLA-4 on cardiac allograft survival and humoral response to soluble Ags. BALB/c hearts were transplanted into C3H/He recipients. mAbs (100 micrograms/day) were administered i.p. for the first 6 days. Graft survival in mice treated with M/K-2 (anti-VCAM-1; median survival: 20 days, n = 6) and those treated with PS/2 (anti-VLA-4; 30 days, n = 6) was greater than that in control mice (8 days, n = 7). Eight of 18 mice treated with both M/K-2 and PS/2 accepted the grafts over 65 days, and five of them accepted the grafts over 100 days. Allografts treated with the two mAbs showed scattered infiltration of leukocytes without evidence of active rejection at 65 days. Mice with long-surviving cardiac grafts were challenged with skin grafts from donor and third-party (C57BL/6) strains. Survival of the donor-type skin was significantly greater than that of the third-party skin. One mouse specifically accepted the donor-type skin indefinitely (> 150 days). FACS analysis of splenocytes at 55 days after transplantation showed complete recovery of VLA-4 expression from a down-regulation observed at day 7. In addition, mice immunized with heat-aggregated human gamma-globulin did not produce specific Ab, even after boost immunization, if PS/2 was administered at the time of the first immunization. This unresponsiveness to xenogeneic protein lasted for more than 50 days. These results indicate that in vivo administration of anti-VCAM-1 and anti-VLA-4 mAbs induces specific immunosuppression to cardiac allografts and soluble Ags.

Animals↗
PubMed1994

Origin of a T cell clone with a mismatched combination of MHC restriction and coreceptor expression.

Although the existence of a large number of CD8+ class II MHC-specific CTLs had long been noticed, the origin of such T cells with a discordant combination of specificity and phenotype has been a mystery in the positive selection model. Recent reports suggesting the independency of the positive selection of T cells from coreceptor-mediated signals raised a possibility that they might be the progeny of putative transitional, mismatched, single-positive cells appearing before positive selection as proposed in the stochastic/selective model. By developing transgenic mice carrying TCR alpha and beta chain genes of a CD8+ class II MHC Ag-specific allogeneic CTL clone QM11, the origin of such T cells with mismatched TCR specificity and coreceptor expression was studied. The results indicate that QM11 belongs to a conventional CD8+ T cell population whose maturation is dependent on a class I (or class I-like) MHC product. Consequently, the reactivity of QM11 to I-Ak can be considered to be an accidental cross-reaction.

Animals↗
PubMed1994

Extracorporeal shock wave lithotripsy (ESWL) for biliary stones: a nationwide survey in Japan.

To assess the current status of extracorporeal shock wave lithotripsy (ESWL) for the treatment of gall-stones in Japan, we conducted a nationwide survey by sending a questionnaire to 251 institutions using this therapy. Replies were obtained from 50 institutions. The use of ESWL was investigated over the period from its introduction up to October 1992. ESWL was performed on 2,760 of 10,058 patients with gallstones (27.4%). The stones were completely pulverized in 1,021 of these 2,760 patients (37.0%). Complete disappearance was limited to single gallstones less than 20 mm in maximum diameter. A comparison in the number of ESWL sessions revealed no significant difference between the patients with and without a good response. Choledocholithiasis was resolved completely in 44.0% of 157 patients who underwent ESWL for this condition and intrahepatic stones were cured in 18.7% of 32 patients. Therefore, ESWL may be a useful form of conservative therapy for biliary calculi.

Cholelithiasis↗
PubMed1994

Reversed-phase high-performance liquid chromatography assay for recombinant acidic fibroblast growth factor in E. coli cell suspensions and lysate samples.

A reversed-phase HPLC assay for acidic Fibroblast Growth Factor (aFGF) expressed in E. coli is described. The assay was developed on a Polymer Labs. PLRP-S macroporous poly(styrene-benzene) column. A sample preparation procedure was developed to permit quantitation of aFGF in crude samples, such as cell suspensions and cell lysates. The assay was linear over the range of 25-140 micrograms/ml with an accuracy of 5%. By using a POROS column containing a stationary phase with "through-pores" and a superficial mobile phase velocity of 1440 cm/h, the analysis could be performed in 3 min. The polymeric supports used for this assay were durable; periodic washing with sodium hydroxide maintained column performance for extended periods.

Chromatography, High Pressure Liquid↗
PubMed1994

Epidemics of aseptic meningitis due to echovirus 30 in Japan. A report of the National Epidemiological Surveillance of Infectious Agents in Japan.

Two rages of epidemic of aseptic meningitis (AM) due to echovirus 30 (E30) in Japan were analyzed with respect to two sources of information, AM incidence and E30 isolation, both gathered through the National Epidemiological Surveillance of Infectious Diseases. The first E30 epidemic spread throughout Japan in 1983 and ceased within the year. The second epidemic, starting in 1989, continued for the three successive years, and in the last year, 1991, the total E30 reports numbered 4,061, the largest number of a single virus type ever reported. Although the epidemic showed temporal and geographical shift and lasted for one or two years in some areas, most laboratories reported the largest number of E30 isolation in 1991. Among E30-yielding cases with clinical information during 1982-1992, the associating frequency with AM was as high as 82.5%. Other central nervous system involvements such as encephalitis, myelitis, encephalomyelitis and/or paralysis were reported in 36 E30-yielding cases and their monthly and age distributions were different from those of AM cases. The proportion of such disease among E30-yielding cases (0.60%) was close to that of other enteroviruses (0.56%). During the epidemics, E30 was isolated more frequently from cerebrospinal fluid than was E4 or E9 which prevailed coincidentally. E30 was most frequently isolated from cases of 4-7 years of age, sharing the common characteristic pattern of age distribution with other enteroviral meningitis. E30-yielding cases, however, involved a large number of older age groups than those of other enterovirus infections, and this tendency was the most pronounced in the first epidemic year, 1983. The contribution of these E30 epidemics on the yearly trend of clinically reported AM incidence and on the shift of its age distribution was also analyzed.

Adolescent↗