Biomedical subjects

Y Yamano

Publications and source records attributed to Y Yamano.

At least 73 records · Page 4Linked to original sources

PubMed1998

Involvement of the RpoN protein in the transcription of the oprE gene in Pseudomonas aeruginosa.

OprE is a channel-forming outer membrane protein of Pseudomonas aeruginosa, the expression of which is induced under anaerobic conditions. We constructed various mutants and observed the effects on oprE expression. Deficiency in RpoN, an alternative sigma factor for RNA polymerase, abolished oprE expression under aerobic conditions, but did not affect the expression under anaerobic conditions. One mutation on the putative RpoN recognition site also caused reduction of oprE expression. The region 500 nucleotides upstream of the mRNA start site was required for optimal oprE transcription, which contains an AT-rich region including a putative integration host factor binding site. These results indicate that OprE production is directly or indirectly controlled by RpoN but also require some other regulatory proteins bound to the upstream region.

Aerobiosis↗

PubMed1998

Reflux of HTLV-I infected lymphocytes from the privileged compartment(s) to peripheral blood flow in patients with HTLV-I-associated myelopathy.

To understand the mechanisms involved in the pathogenesis of human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), three in vivo phenomena which have been observed in the peripheral blood of patients and differing from that in asymptomatic HTLV-I carriers must be taken into consideration: (a) the presence of increased HTLV-I viral load, (b) a higher immune responsiveness against HTLV-I antigens, and (c) biased nucleotide substitutions in the HTLV-I pX region which indicate a decreased selection pressure for viral amino acid changes. We now propose a hypothesis which focuses on the in vivo dynamics of HTLV-I infected lymphocyte migration and which incorporates these features. In addition, the hypothesis assumes the existence of a deviation in immune surveillance for HTLV-I in the central nervous system (CNS) in spite of the presence of frequent specific immune effectors. We suggest that in the active phase of HAM/TSP, accompanied with or following autoaggressive interactions between infected lymphocytes and immunocompetent cells in the CNS, there is a consequential reflux of the infected lymphocytes to the peripheral blood. The reflux of infected cells would be expected to provide peripheral blood with tissue-derived HTLV-I proviruses which have been indulged and propagated in an immune-privileged site. This process would result in and account for the observed increase in viral load and the substitution bias in HTLV-I sequences in the peripheral blood.

Deltaretrovirus Antibodies↗

PubMed1998

Local application of basic fibroblast growth factor minipellet induces the healing of segmental bony defects in rabbits.

Fibroblast growth factor (FGF) has been reported to increase the volume of callus in a fracture model of rats. There are, however, no reports of successful repair of segmental bony defects by application of an FGF solution. In this study, the effects of basic FGF on the repair of segmental bony defects in the rabbit femur were examined. Minipellet, a new drug delivery system using atelocollagen, was employed to ensure effective delivery of FGF. Segmental bony defects (10 mm in length) were created in the right femurs of 19 rabbits. In pilot studies, no defects of this size healed spontaneously within 6 weeks. Bones were stabilized with miniexternal fixators. Minipellets containing basic FGF were implanted between fragments so as to bridge the two fragments. The healing processes were monitored radiographically and studied histologically. In rabbits in which FGF was added to the defect site at doses of 1.4 microgram or higher, approximately 90% of the defects were filled with new bone and cartilage within 6 weeks after minipellet implantation. In rabbits receiving placebo minipellets, however, approximately 15% of the defects were filled by callus within 6 weeks. Furthermore, this callus did not change into mature bone. An injection of 2 microgram of FGF solution to bony defects had no effect on the repair of segmental bony defects. These findings suggest that FGF plays a role in the production of adequate volumes of callus particularly in the initial stages of fracture healing and that sustained local release enables FGF to be effective at a low dose. In summary, large segmental bony defects healed after insertion of low-dose FGF minipellets. An adequate dose of FGF and an appropriate delivery system are required for successful healing of large bony defects. These findings imply the potential value of FGF minipellets in clinical practice.

Animals↗

PubMed1998

Human CD4+ T lymphocytes recognize a highly conserved epitope of human T lymphotropic virus type 1 (HTLV-1) env gp21 restricted by HLA DRB1*0101.

HTLV-1 causes two distinct human diseases, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T cell leukaemia/lymphoma (ATL). Persistently infected individuals carry a risk of <1% of developing either disease. These basic epidemiological data imply that virus-host interactions, especially immunogenetic factors, influence the outcome of infection. Several studies showed that the HLA class II DR1 DQ5 haplotype is over-represented in HAM/TSP, but rare in ATL. Therefore, we selected four patients with HAM/TSP and one seronegative control who all carried the HLA DR1 DQ5 haplotype. We analysed the CD4+ T lymphocyte response against eight synthetic peptides of HTLV-1 envelope (env) glycoprotein gp21, a crucial target antigen in HAM/TSP. The first of two immunodominant epitopes corresponded to a domain of the HTLV-1 envelope protein which had previously been shown to be essential for HTLV-1 envelope function. The second immunodominant epitope overlapped a highly conserved sequence of the retroviral transmembrane envelope protein. DR1 (DRB1*0101)-restricted T lymphocytes were activated by the conserved peptide sequence in nanomolar concentrations. In contrast, this conserved sequence can also induce non-specific, cAMP-mediated immunosuppressive effects on T cells when added in micromolar concentrations to culture media, as shown by Haraguchi S, Good RA, James-Yarish M, Cianciolo GJ, Day NK, Proc Natl Acad Sci USA 1995; 92:5568-71. Hence, HTLV-1 env gp21 might exert either stimulating immunological or immunosuppressive effects in HTLV-1-infected individuals, depending on the level of its expression and the presence of HLA DRB1*0101.

Amino Acid Sequence↗

PubMed1998

A study of multiple biomarkers in coke oven workers--a cross-sectional study in China.

We conducted a cross-sectional molecular epidemiological study of coke oven workers exposed to the established carcinogen polycyclic aromatic hydrocarbons (PAHs) to evaluate the relationships between both traditional 'exposure markers' and a series of biomarkers, including urinary 1-hydroxypyrene as a marker of internal dose, leukocyte aromatic DNA adducts as markers of biologically effective dose, serum p53 protein as a response marker and genetic polymorphisms of cytochrome P4501A1 and glutathione S-transferase MI as susceptibility markers. Twenty-five male subjects each were randomly selected from the top, middle and bottom work areas of the oven, and the control plant. They were matched for age and smoking status. The mean levels of PAH exposure, monitored by stationary and personal samplers, and of worker urinary 1-hydroxypyrene differed significantly between the top, middle and bottom of the oven and control work areas. The highest stationary and personal PAH concentrations and 1-hydroxypyrene levels were demonstrated at the top work area. Good correlations were found between the stationary PAH levels, personal PAH levels and urinary 1-hydroxypyrene levels. No positive correlations were demonstrated between aromatic DNA adduct levels and current or cumulative PAH exposure dose. In the presence of genetic polymorphisms of cytochrome P4501A1, a positive correlation was demonstrated between aromatic DNA adducts and urinary 1-hydroxypyrene levels. There was also a significant correlation between serum p53 protein levels and the cumulated benzo[a]pyrene exposure dose. Although these biomarkers have certain limitations, they are applicable to cancer epidemiology, and may contribute to our understanding of the mechanisms of carcinogenesis.

Adult↗

PubMed1998

Structure of genes for cecropin A and an inducible nuclear protein that binds to the promoter region of the genes from the silkworm, Bombyx mori.

Cecropins are a family of antibacterial peptide synthesized in insects as a response to bacterial infection. To study the regulation of the immune genes in insects, two cecropin A genes were cloned and sequenced from the silkworm, Bombyx mori. The two genes, CecA1 and CecA2, encoded identical preprocecropin A, having one intron of 609 bp and 929 bp, respectively. The 5'-upstream regions of the genes contained a NF-kappa B like element and IL-6-RE Type I element. Electrophoretic mobility shift assay revealed that a nuclear protein of fat body which specifically bound to the kappa B-like element was activated by injection of the larvae with peptidoglycan.

Amino Acid Sequence↗

PubMed1998

Alteration in the differentiated phenotypes of cultured chondrocytes from human articular cartilage under various culture conditions.

Chondrocytes produce proteoglycans and type II collagen as their main matrix components, which can also be considered to be indices of their differentiated phenotype. Each differentiation step occurs in accordance with the environment of each cell. The analysis of the properties of chondrocytes has mostly been performed in cultured cells. In this report, we examined the effects of the culture media and fetal calf serum on cultured human articular chondrocytes. It was confirmed that the quantity of proteoglycan produced by the chondrocytes changed according to the different kinds of media used, and that the molecular size of the proteoglycans showed a tendency towards de-differentiation with decreasing fetal calf serum concentrations. We conclude that our experimental results which are obtained in cultured human articular chondrocytes should be discussed with consideration to the finding of this report.

Cartilage, Articular↗

PubMed1998

Molecular cloning and expression of the canine metallothionein-III gene.

We have isolated and determined the complete nucleotide sequence of canine metallothionein-III (MT-III) cDNA. The predicted amino acid sequence of the canine MT-III showed a high homology (93%, 87% identity) to that of human and mouse MT-III. The canine MT-III had 2 insertions relative to known mammalian MT-I and MT-II: a threonine after the 4th amino acid and a block of 6 amino acids near the carboxyl terminus. Expression of the canine MT-III mRNA was found exclusively in the central nervous system, where neurons in the olfactory bulb, hippocampus and cerebral cortex showed predominant signals.

Amino Acid Sequence↗

PubMed1998

Contrast enhanced magnetic resonance imaging for femoral neck fracture.

Femoral head perfusion was evaluated in 29 patients after acute femoral neck fracture using contrast enhanced fat saturation magnetic resonance imaging. The patients were followed up with T1 and T2 weighted spin echo magnetic resonance imaging without fat saturation, which is suitable in detecting avascular necrosis. The mean interval from injury to the initial contrast enhanced fat saturation magnetic resonance imaging was 24.5 hours. The mean age at the time of injury was 69 years, and the mean followup was 26.9 months. Three distinct patterns of femoral head enhancement were recognized in the acute phase after fracture. When the whole femoral head was well enhanced (Type 3, n = 11), no avascular necrosis developed. In contrast, when the head showed no enhancement (Type 1, n = 6), avascular necrosis developed in all patients. In patients with partial enhancement (Type 2, n = 12), avascular necrosis developed in five patients. These data showed the current method provided an accurate prediction of the development of avascular necrosis in the patients with Type 1 and Type 3 enhancement. However, overall predictive value was 59% (17 of 29 patients) because of the uncertainty in the patients with partial enhancement (Type 2), and additional study is needed for this method to become routine in clinical use.

Adolescent↗

PubMed1997

Eicosanoids mediate induction of immune genes in the fat body of the silkworm, Bombyx mori.

The expression of cecropin and lysozyme genes is induced in response to bacterial peptidoglycan in the fat body of the silkworm, Bombyx mori. Specific inhibitors of either phospholipase A2, cyclooxygenase or lipoxygenase significantly inhibit the induction of the immune genes both in vivo and in cultured fat body as detected by means of Northern hybridization. Arachidonic acid injected into the larvae induces the expression of the cecropin and lysozyme genes. The findings support the idea that eicosanoids mediate some process leading to the expression of immune genes in the fat body following recognition of peptidoglycan as a signal for invading bacteria.

Animals↗

PubMed1997

Lumbar spinal canal stenosis examined electrophysiologically in a rat model of chronic cauda equina compression.

STUDY DESIGN: A model of chronic cauda equina compression with conductive stress was studied electrophysiologically. OBJECTIVE: To analyze the pathophysiology arising from chronic compression electrophysiologically. SUMMARY OF BACKGROUND DATA: This rat model of cauda equina compression that is chronic, not acute, has been reported elsewhere. METHODS: A stainless steel wire and plate were fastened to the spine at L5 of 8 rats 3 weeks old. One year later, the ascending and descending nerve action potentials were recorded and the conduction velocities (CVs) were measured. Electrophysiologic changes after high-frequency stimulation (HFS) were observed. RESULTS: The waveform of the ascending cauda equina action potential at the cauda equina had three peaks, and that at the conus medullaris had a peak followed by a broad wave. The waveform of the descending nerve action potential had two peaks. The mean ascending and descending CVs of the treated rats were slower (P < 0.001) than those of the control rats. In the control rats, the mean CV and mean amplitude after HFS decreased slightly and returned to normal within 30 seconds, and the waveform was unchanged. In treated rats, the mean CV decreased after HFS but returned to normal within 10 minutes. The mean amplitude decreased after HFS and did not return to normal within 10 minutes. The waveform was unchanged. CONCLUSIONS: Because the differences between treated and control rats in amplitude (and CVs) were greater before HFS than after HFS, we concluded that treated rats had disturbance of the blood flow in vessels around the nerves of the cauda equina with histologic damage. In human patients, such disturbance may be one cause of intermittent claudication.

Action Potentials↗

PubMed1997

Alteration of cytokine levels by fosfomycin and prednisolone in spontaneous proliferation of cultured lymphocytes from patients with HTLV-I-associated myelopathy (HAM/TSP).

Fosfomycin has recently been reported as an antibiotic with immunomodulatory activities. To evaluate the possibility of clinical administration of fosfomycin in patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), the effects of this agent on the HTLV-I-induced in vitro phenomenon were studied. The influence of fosfomycin on in vitro spontaneous proliferation (SP) of peripheral blood mononuclear cells (PBMCs) from four patients with HAM/TSP was measured by thymidine incorporation into the cells, and the concentration of several cytokines in the culture supernatants was examined in three HAM/TSP patients. Enzyme-linked immunosorbent assays (ELISAs) were employed to detect the concentrations of interleukin-4 (IL-4), IL-6, IL-10, interferon-gamma (IFN-gamma), transforming growth factor-beta1 (TGF-beta1), and macrophage inflammatory protein-1alpha (MIP-1alpha). The data were compared to the changes by prednisolone which is known to regulate the HTLV-I-associated in vitro phenomenon and to have a therapeutic benefit in patients with HAM/TSP. Production of IL-6, IFN-gamma and MIP-1alpha from the spontaneously proliferating cells were demonstrated. Fosfomycin could not suppress the HTLV-I-associated SP, but had the properties to decrease the levels of TGF-beta1 and MIP-1alpha. It was also demonstrated that the concentrations of IFN-gamma and MIP-1alpha in the cultures in the presence of prednisolone were apparently decreased, suggesting a possible involvement of these cytokines in the pathogenesis of HAM/TSP. These findings support the hypothesis that fosfomycin may have immunomodulatory potentials in HTLV-I-related cellular interactions in a different manner from ordinary immunomodulatory agents.

Adult↗

PubMed1997

A domain for G protein coupling in carboxyl-terminal tail of rat angiotensin II receptor type 1A.

To delineate domains essential for Gq protein coupling in the C-terminal region (C-tail) of rat angiotensin II (Ang II) receptor type 1A (AT1A), we modified the putative cytosolic regions of the receptor by truncation or alanine substitution and determined resultant changes in the guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) effect on Ang II binding and inositol trisphosphate production by the agonist. Independently, we studied the effect of synthetic C-tail peptides (P-5) and its alanine substitution analogs on [35S]GTPgammaS binding to Gq. Effects of GTPgammaS on Ang II binding (shift to a low affinity form) and inositol trisphosphate production in the deletional mutant receptor 1-317 AT1A was similar to wild type AT1A, whereas in shorter C-terminal deletion mutants 1-309, 1-311, 1-312, 1-313 AT1A, and substitutional mutants Y312A, F313A, and L314A these activities were markedly reduced. The binding of [35S]GTPgammaS to Gq was promoted by the synthetic C-terminal peptide P-5 but not when mutated at Tyr312, Phe313, or Leu314. Results indicate that Tyr312, Phe313, and Leu314 in cytosolic carboxyl-terminal region of rat AT1A are essential for coupling and activation of Gq.

Amino Acid Sequence↗

PubMed1997

Urinary 1-hydroxypyrene levels of garbage collectors with low-level exposure to polycyclic aromatic hydrocarbons.

Because garbage collectors work in the street, they are exposed to polycyclic aromatic hydrocarbons (PAHs) in motor vehicle exhaust gas as they work. Urinary 1-hydroxypyrene (1-OH-pyrene) began to be used as a biological monitoring index for human exposure to high concentrations of PAHs. The objective of this study was to examine the applicability of urinary 1-OH-pyrene as a biological monitoring index for human low-level PAH exposure, such as the PAH exposure experienced while working in the street. The subjects were fifteen male garbage collectors. We measured individual exposure to PAHs, urinary 1-OH-pyrene concentrations and urinary cotinine concentrations. Individual air samplers were attached to the collar of the clothing of five workers to capture PAHs. Urine samples were collected before work, around noon and after finishing the day's work. In all, five PAH samples and 45 urine samples were collected. As control data, we analyzed the urinary 1-OH-pyrene and urinary cotinine levels of six smoking and four non-smoking control subjects who were not occupationally exposed to PAHs. The benzo[a]pyrene level in the air sampled for 5-6 h was 2.5-10.5 ng/m3, and the pyrene level as 10.3-70.3 ng/m3. These levels were similar to those in the vicinity of streets in Japan. A positive correlation between total PAH levels and the pyrene levels was observed. The average urinary 1-OH-pyrene level of the smokers was 0.21 +/- 0.13 mumol/mol creatinine, vs. 0.15 +/- 0.11 mumol/mol creatinine in the non-smokers. The urinary 1-OH-pyrene level obtained in this study was slightly higher than in the control group. No correlation was found between pyrene exposure and the urinary 1-OH-pyrene level of the five workers who wore the personal samplers. A significant positive correlation was observed between the urinary 1-OH-pyrene level and urinary cotinine level of the smokers. A significant positive correlation was also observed between the urinary 1-OH-pyrene and urinary cotinine levels of the control group smokers. In conclusion, urinary 1-OH-pyrene is not applicable for biological monitoring of extremely low levels of exposure to PAHs, as in the case of working in the street. Caution is required to exclude the effects of smoking when evaluating PAH exposure.

Adult↗

PubMed1997

In vitro virus propagation and high cellular responsiveness to the infected cells in patients with HTLV-I-associated myelopathy (HAM/TSP).

The reasons for the development of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in certain infected individuals remain poorly understood, but the susceptibility should involve both viral factors and host conditions. To assess simultaneously both virus-induced activation of infected cells and the cellular response to virus producing cells, an analysis of fractionated peripheral blood lymphocytes obtained from patients with HAM/TSP (n = 15) were compared with those of asymptomatic HTLV-I carriers (n = 9) in an age-matched manner. The in vitro propagation of HTLV-I infection was evaluated as the spontaneous thymidine incorporation into CD4+ cells, and proliferative response of CD8+ cells against cultured and irradiated autologous CD4+ cells was employed to analyze the HTLV-I-induced cellular response. The comparative analysis using these two parameters demonstrated that HAM/TSP patients were characterized by the concomitance of a high inducibility of HTLV-I propagation and a high cellular responsiveness against HTLV-I as compared with asymptomatic HTLV-I carriers, suggesting the involvement of both of these factors in disease susceptibility. In addition, the coupled evaluation of these two in vitro phenomena may offer a better diagnostic hallmark for HTLV-I seropositive myelopathy cases with other known cause of myelopathy.

Adult↗

PubMed1997

Preferential recognition of synthetic peptides from HTLV-I gp21 envelope protein by HLA-DRB1 alleles associated with HAM/TSP (HTLV-I-associated myelopathy/tropical spastic paraparesis).

To determine CD4+ T-cell epitopes of HTLV-I-envelope protein recognized by the HLA alleles associated with HAM/TSP, we established 20 CD4+ T-cell lines from peripheral blood mononuclear cells (PBMCs) of naive healthy donors using a panel of synthetic peptides spanning the entire length of HTLV-I-envelope proteins, gp46 and gp21. We quantitated the precursor frequencies of HTLV-1-envelope specific CD4+ T-cells and analyzed epitope specificity in the context of HLA alleles. The precursor frequencies ranged from 3.0 to 10.6 per 10(7) PBMCs in the naive healthy donors. The CD4+ T-cell epitopes of HTLV-I-envelope protein were clustered in amino acids 76 to 90, 136 to 160, 171 to 185 and 196 to 210 of gp46, and in amino acids 366 to 400 and 436 to 485 of gp21. The CD4+ T-cell epitopes of gp21 were preferentially recognized by HLA-DRB1 0101 and 1502 which were known to be associated with HAM/TSP. Thus, it was suggested that HTLV-I gp21 might contain the major CD4+ T-cell epitopes recognized by HLA-DRB1 alleles of HAM/TSP.

Alleles↗

PubMed1997

Effects of cigarette smoking on the serum concentration of lung surfactant protein A (SP-A).

We have tested the hypothesis that serum surfactant protein A (SP-A) production may be affected by cigarette smoke exposure, and that alterations in serum levels may reflect smoking habits. A total of 52 subjects were divided into the following two groups: active smokers (Group A; n = 23); and nonsmokers (Group B; n = 29). The assessment of smoking habit was determined by self-report, carbon monoxide concentration in expired air, and cotinine concentration in urine. Serum SP-A was compared in both groups and was found to be higher in Group A (active smokers) (p < 0.002). We conclude that surfactant protein A levels are increased in the serum of smokers. However, it was found that this is not a sensitive discriminating factor to separate smokers from nonsmokers.

Adult↗

PubMed1997

[Combined effect of adoptive immunotherapy (AIT) with lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2) and chemotherapy in tumor-bearing mice].

We investigated beneficial effects of AIT with anticancer agents on survival of subcutaneous tumor-bearing mice and suppression of artificial lung metastasis, and optimal schedule of administration of each treatment in vivo. 7-8 weeks old C 57 BL/6 mice were inoculated s.c. with 5 x 10(6) B 16 melanoma cells, or i.v. with 2 x 10(5) B 16-F 10 melanoma cells. Mouse splenocytes were cultured with 3.5 x 10(3) JRU/ml interleukin 2 for 14 days, and induced LAK cells were harvested. Anticancer agents (Cx), CDDP or MMC were given i.p. in mice. 1 x 10(7) or 5 x 10(7) LAK cells were given either s.c. around the tumor or i.v. respectively, and 1.4 x 10(5) JRU/mouse IL-2 was administered s.c. for 6 days after LAK cell injection. Therapy groups were as follows #1: Cx day 3, AIT day 3-8. #2: Cx day 3, AIT day 6-11, #3: Cx day 8, AIT day 3-8. In therapy groups #1 and #2, we observed additive effects of AIT and anti-cancer agents in life-prolongation and suppression of lung metastasis. It was also shown that LAK induction in vivo was augmented by anticancer agents in groups #1 and #2, which might represent one of the mechanisms behind observed additive effects. Furthermore, our results suggest that therapeutic effects of the combination of AIT and anticancer agents depend on the schedule of administration.

Animals↗