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Biomedical subjects

K Yamaji

Publications and source records attributed to K Yamaji.

At least 19 recordsLinked to original sources
PubMed2001

Antimicrobial cuparene-type sesquiterpenes, enokipodins C and D, from a mycelial culture of Flammulina velutipes.

Two new cuparene-type sesquiterpenes, enokipodins C (1) and D (2), were isolated from culture medium of an edible mushroom, Flammulina velutipes, along with enokipodins A (3) and B (4). The structures of 1 and 2 were determined using spectroscopic methods (HRMS, (1)H and (13)C, and 2D NMR). The absolute configuration of enokipodin C was determined from the observed (1)H NMR chemical shifts and NOEs in NOESY experiments after conversion into the corresponding esters with the chiral reagent 2-(2'-methoxy-1'-naphthyl)-3,4-dichlorobenzoic acid. All the metabolites showed antimicrobial activity against a fungus, Cladosporium herbarum, and Gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus.

Antifungal Agents↗
PubMed2001

Effect of aging on bone formation induced by recombinant human bone morphogenetic protein-2 combined with fibrous collagen membranes at subperiosteal sites.

This study was designed to examine the effect of aging on bone formation induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with a fibrous collagen membrane (FCM). Implantation was done subperiosteally in bilateral palatal grooves in 34 male Wistar rats divided into three age groups: a 10-week-old group (10w group), a 30-week-old group (30w group) and a 70-week-old group (70w group). RhBMP-2-combined FCMs were implanted on the left palatal grooves as BMP-implanted sites (BMP site), while rhBMP-2 was not implanted on the right palatal grooves as control sites. The rats were sacrificed 6 weeks after implantation, and histometric evaluations were performed. New bone formation was observed in every site of each age group and the new bone was almost completely continuous with the original bone. The new bone volume (NBV) of the BMP site was significantly higher than that of the control site in each age group. The NBV of both the control and BMP sites were highest in the 10w group and lowest in the 70w group. The disparity of NBV between the control and BMP sites, which indicated the response to implanted BMP excluding the effect of skeletal growth and surgical stimulation, did not significantly differ among the age groups. These results indicate that rhBMP-2-combined FCM has the ability to induce new bone formation continuous with original bone even in senescent rats. Furthermore, it appeared that, in the case of palatal subperiosteal implantation, the responsiveness to implanted BMP was independent of age, although the total volume of newly formed bone declined with aging.

Aging↗
PubMed2000

B cell receptor engagement and T cell contact induce Bcl-6 somatic hypermutation in human B cells: identity with Ig hypermutation.

The human bcl-6 proto-oncogene has been found to be mutated in both neoplastic and normal B cells. We used CL-01 cells, our monoclonal model of germinal center differentiation, and normal human B cells to explore the induction requirements and the modalities of bcl-6 hypermutation. As we have previously shown, CL-01 cells are IgM+ IgD+ and effectively mutate the expressed Ig VHDJH and V lambda J lambda genes and switch to IgG, IgA, and IgE upon B cell receptor engagement and contact with CD4+ T cells through CD40:CD154 and CD80:CD28 coengagement. In this paper we showed that the same stimuli induce somatic hypermutation of bcl-6 in CL-01 and normal IgM+ IgD+ B cells. bcl-6 hypermutation was not accompanied by translocation of this proto-oncogene or hypermutation of the beta-actin gene, and it did mimic Ig hypermutation. It was associated with transcription initiation, in that it targeted the first exon and a 696-bp sequence immediately downstream (approximately 0.6 kb) of the transcription initiation site while sparing further downstream (approximately 2.5 kb) and upstream (approximately 0.1 kb) areas. bcl-6 hypermutation displayed an overall rate of 2.2 x 10-4 changes/base/cell division with characteristic nucleotide preferences and showed strand polarity. These findings show that B cell receptor engagement promotes hypermutation in genes other than Ig, and suggest that cis-regulating elements similar to those of the Ig locus exist in bcl-6.

Amino Acid Motifs↗
PubMed2000

Highly oxidized cuparene-type sesquiterpenes from a mycelial culture of Flammulina velutipes.

Cuparene-type sesquiterpenes were isolated from a culture broth of Flammulina velutipes (Curt.:Fr.) Sing. Using spectroscopic methods (HR-MS, 1H and 13C NMR, and 2D NMR, spectroscopy), their structures were determined to be 2,3,4,5-tetrahydro-2,7-dihydroxy-5,8,10,10-tetramethyl-2,5-methano-1- benzoxepin and 5-methyl-2-(3-oxo-1,2,2-trimethylcyclopentyl)benzoquinone. Both showed antimicrobial activity against Cladosporium herharum and Bacillus subtilis.

Anti-Infective Agents↗
PubMed2000

Effects of abstinence from cigarette smoking on the cardiorespiratory capacity.

PURPOSE: The purpose of this study was to determine the effect of 6 or 7 d of abstinence from cigarette smoking on the cardiorespiratory capacity of young men. METHODS: The subjects were 11 male volunteers, mean age 20.5 yr. Their mean smoking duration and cigarettes smoked per day were about 3.5 yr and 20.5 cigarettes, respectively. On the first day of the study, the subjects' physical characteristics, pulmonary functions, and maximal oxygen debt predicted by bicycle ergometer exercise were measured. The subjects' heart rate at rest (HRrest), blood pressure, venous blood analysis and maximal oxygen intake (VO2max) in a treadmill exercise test were measured on the second day. From the time of the second-day measurements, the subjects abstained from cigarette smoking. On the eighth and ninth days of the study, the same measurements were taken as the measurements of the first and second days, respectively. RESULTS: The changes between before and after abstinence from smoking were as follows. The plasma cotinine had almost disappeared after the 7 d of abstinence from smoking. Pulmonary functions did not show a significant improvement. Although there were no significant changes in the HRrest or systolic or diastolic blood pressure, the pulse pressure was significantly increased (P < 0.05). Although the blood components were not changed significantly, the PO2, O2 saturation, HCO3, and CO2 concentration were significantly increased. The predicted maximal oxygen debt was not significantly decreased. Although the VO2max and maximal ventilation volume were not changed, the exercise time was significantly prolonged (P < 0.001). The heart rate during the treadmill exercise at almost all stages decreased significantly; however, the maximal heart rate did not change. CONCLUSION: In conclusion, exercise performance was improved by the 7 d of abstinence from smoking.

Adult↗
PubMed2000

Effect of leptin in platelet and endothelial cells. Obesity and arterial thrombosis.

We demonstrated that leptin showed effects on both platelets and endothelial cells through its functional receptor. These effects are the vector to inducing thrombotic tendency. Leptin concentrations used in our experiments correspond to that of leptin in the circulation of obese individuals. Thus we suggest that increased leptin may act as a risk factor for thrombosis in obese individuals.

Adenosine Diphosphate↗
PubMed1999

Ultrasonic tissue characterization in patients with dilated cardiomyopathy: comparison with findings from right ventricular endomyocardial biopsy.

AIM: The clinical usefulness of integrated backscatter (IB) imaging was compared with right ventricular endomyocardial biopsy for assessing myocardial damage in patients with dilated cardiomyopathy (DCM). METHODS: We examined 15 patients with DCM and 20 healthy controls. In addition to the conventional M-mode echocardiographic parameters, we determined the cyclic variation in IB values (CV-IB) obtained from parasternal short axis views of the left ventricle just under the transducer for both the interventricular septum (IVS) and the left ventricular posterior wall (PW). The per cent fibrosis area (%) and the transverse diameter of myocytes (microm) were measured in right ventricular endomyocardial biopsy specimens by computer image analysis. To analyze the relationship between pathological findings and CV-IB, we divided patients into four subgroups on the basis of the pathological characteristics of endomyocardial biopsy specimens as follows: degeneration dominant group (n = 5), fibrosis dominant group (n = 5), dilated phase hypertrophic cardiomyopathy (n = 2), and mixed type (n = 3). RESULTS: CV-IB in the IVS and the PW was lower in patients with DCM (8.8 +/- 2.9, 8.3 +/- 2.7 dB, respectively) than in normal subjects (14.4 +/- 2.9, 13.6 +/- 2.6 dB, respectively). Biopsy findings showed a mean per cent fibrosis area of 24.0 +/- 12.3%, and a mean myocyte diameter of 14.3 +/- 2.9 microm in patients with DCM. CV-IB was correlated with both of these findings: per cent fibrosis area (r = -0.56 in IVS, r = -0.56 in PW) and myocyte diameter (r = 0.67 in IVS, r = 0.71 in PW). CV-IB was decreased in all DCM subgroups compared with normal subjects, but there was no significant difference between subgroups. CONCLUSIONS: CV-IB was correlated with both the extent of fibrosis in myocardial tissue and the myocyte diameter. These findings suggest that ultrasonic tissue characterization is a good indicator of the severity of fibrosis and myocyte atrophy in patients with DCM.

Biopsy↗
PubMed1999

In vitro comparison study of CD63 and CD62P expression after contacting leukocyte filters.

CD63 and CD62P have been recognized as platelet activation markers. This study investigated the secretion of these antigens to compare the platelet activation between a newly developed stainless steel leukocyte filter (SSLF) and 7 polyester or polyurethane commercially available leukocyte filters. Flow cytometry demonstrated that the SSLF initiated significantly smaller effects in terms of mean fluorescence intensity of CD63 (p<0.03) and of the amount of CD62P expressing platelets (p<0.002) compared to the polyurethane filters. However, there was no statistical difference between the SSLF and polyester filters. The result of this study suggests that the SSLF caused less platelet activation than the polyurethane filters and has biocompatible characteristics comparable to the currently available polyester filters. Stainless steel was selected because of its physicochemical conductivity. With these results, further evaluation of the SSLF will be continued in an attempt to develop an active immunomodulator using this unique characteristic.

Adult↗
PubMed1999

[Efficacy of influenza vaccine among geriatric inpatients: effect of previous vaccination and antibody induction by single and twice injections].

To investigate the effect of previous influenza vaccination and the difference in antibody induction by single and twice injection of influenza vaccine in the elderly, hemagglutination inhibition (HI) antibody titers of the three types of influenza viruses were measured. Influenza vaccination was done for 217 inpatients. For the patients who had influenza vaccination in the year prior to the study, influenza vaccine was administered once to 77 patients and twice to another 70 patients. Influenza vaccine was injected twice to 70 patients who had not received influenza vaccine in the previous years. The influenza vaccine induced an increase in HI titer in almost all patients. The geometric mean of the HI titer and the frequency of patients with HI titers over 128x were similar after vaccination in the groups of patients who were injected twice, irrespective of whether or not influenza vaccination was given in the year prior to the study. The geometric means of the HI titers for influenzas A/H3N2 and B and the frequency of HI titers over 128x for influenza A/H3N2 after vaccination were lower in the patients who received vaccine once than in the patients vaccinated twice. These results suggest that prior vaccination does not diminish antibody response to influenza vaccine significantly in the elderly when influenza vaccine is injected twice. Although single injection is inferior to twice injection in antibody induction with some vaccine virus strains, induction of HI titers over 128x is found in more than 70% of elderly. Single injection of influenza vaccine may be practically effective and useful for protection of influenza infection in the elderly.

Aged↗
PubMed1998

Localization of the apoptosis-inducing activity of lupus anticoagulant in an annexin V-binding antibody subset.

Lupus anticoagulant (LAC) is associated with arterial and venous thrombosis, thrombocytopenia, and recurrent fetal loss. We have reported previously that plasma with LAC activity induces apoptosis in endothelial cells and binds annexin V (Nakamura, N., Y. Shidara, N. Kawaguchi, C. Azuma, N. Mitsuda, S. Onishi, K. Yamaji, and Y. Wada. 1994. Biochem. Biophys. Res. Commun. 205:1488-1493). In this study, we separated two IgG antibody fractions, one with and one without affinity for annexin V, from 10 patients with LAC. LAC and apoptotic activities were localized in the annexin V-binding fraction in all 10 patients. DNA fragmentation was dose-dependent, paralleling the amount of IgG added to the human umbilical vein endothelial cell culture medium, and was inhibited by preincubation with annexin V. Removal of the antiphospholipid antibodies from patient IgG with phospholipid liposomes did not abolish the apoptosis-inducing activities or binding to annexin V. These results imply that patients with LAC often have antibodies that do not bind phospholipids and are responsible for the induction of apoptosis in endothelial cells.

Adult↗
PubMed1998

Expression of a hepatitis C virus NS3 protease-NS4A fusion protein in Escherichia coli.

Both the NS3 protease and the NS4A protein are required for efficient cleavage of the nonstructural protein region of the hepatitis C virus polyprotein. The NS3 protease domain was fused at its C-terminal end with full length NS4A and expressed in Escherichia coli. This protein (NS3 delta-NS4A) was purified to apparent homogeneity after refolding from extracts recovered from inclusion bodies. During the expression and purification process, NS3 delta-NS4A was not auto-processed in either a cis or trans manner at NS3/NS4A junction site. When the kcat/K(m) values and thermostability of NS3 delta-NS4A were compared with those for maltose binding protein-NS3 fusion protein (MBP-NS3), which contains only NS3 region, the single-chain NS3 delta-NS4A showed enhanced proteolytic activities and thermostability.

ATP-Binding Cassette Transporters↗
PubMed1998

Age-related response to interferon alfa treatment in women vs men with chronic hepatitis C virus infection.

BACKGROUND: Interferon alfa is used widely for patients with chronic hepatitis C virus (HCV) infection. Little is known, however, of the relationship between patients' sex and the effectiveness of interferon alfa treatment in these patients. METHODS: We treated 311 patients (199 men and 112 women) with human lymphoblastoid interferon (6 million units subcutaneously every day for 2 weeks and 3 times a week for 22 weeks) and observed them for an additional 6 months. Serum HCV RNA levels and genotype were tested by polymerase chain reaction before treatment. A liver biopsy was also done. For the purposes of this study, a complete response was defined as the elimination of HCV RNA for at least 6 months after the termination of treatment. RESULTS: The rate of complete response was 27.1% for men and 24.1% for women. With multiple logistic regression analysis, the HCV RNA level (P < .001), genotype (P < .001), patients' sex (P < .05), and the interaction between sex and age were associated with a complete response to interferon alfa. The rate of complete response was 33.3% in men aged 39 years and younger, 25.0% in men aged 40 years and older. 75.0% in women aged 39 years and younger, and 15.6% in women aged 40 years and older. The odds ratio by group was 1.00, 0.72, 4.38, and 0.21, respectively. CONCLUSIONS: Our finding that women aged 39 years and younger are responsive to interferon alfa treatment suggests that hormonal activity, in particular the level of estrogen, may be associated with the sustained elimination of HCV.

Adult↗
PubMed1998

Hepatitis C viral RNA status at two weeks of therapy predicts the eventual response.

We investigated the timing of the disappearance and reappearance of serum hepatitis C viral (HCV) RNA in patients with chronic hepatitis C during interferon treatment and follow-up. Serum samples were tested for HCV RNA by polymerase chain reaction in 62 patients with chronic hepatitis C treated with interferon-alpha for 24 weeks. We found that 17 patients obtained complete response, with absence of serum HCV RNA for 6 months after the treatment. Twenty-nine patients had a partial response, with reappearance of serum HCV RNA within 6 months of follow-up, and 16 patients were nonresponders who were positive for serum HCV RNA throughout the observation period. HCV RNA disappeared within 2 weeks of treatment in 31 patients, including all 17 (100%) complete responders and 14 (48.3%) of the 29 partial responders. The patients remaining positive for HCV RNA at the second week were 15 (51.7%) of the 29 partial responders and the 16 nonresponders. In all of the 29 partial responders, viremia recurred within 1 month after the treatment. These results indicate that the status of HCV RNA at the second week of treatment is a useful predictor of effective treatment, whereas status at the first month after cessation of treatment is useful for assessing the effectiveness of interferon itself.

Adult↗
PubMed1998

Current therapeutic apheresis technologies for inflammatory bowel disease.

A large number of physicians have indicated that patients with inflammatory bowel diseases (IBD) such as ulcerative colitis (UC) and Crohn's disease (CD) respond to current apheresis technology treatment. However, the mechanism of the apheresis procedure is undefined for patients with IBD. IBD appears to be caused by a complex of interactions from the genes, environment, and the immune system; therefore, the immune system plays a crucial role in the inflammatory responses. In this process, lots of interactions occur simultaneously, and they cross relate with each other. This review paper briefly discusses the etiology and pathogenesis of IBD and attempts to elucidate the mechanism that occurs after apheresis treatment.

Blood Component Removal↗
PubMed1998

[Impact of influenza epidemics and efficacy of vaccination among geriatric inpatients].

To determine the impact of influenza epidemics among geriatric inpatients and to monitor the clinical efficacy of influenza vaccination, the influenza infection rate in non-vaccinated inpatients was determined serologically and the incidence of febrile episodes and death were compared between the vaccinees and non-vaccinees hospitalized in the referred hospital from January through September, 1995. Three influenza subtypes, influenza A/H1N1, A/H3N2, and B, were endemic simultaneously from January to March in 1995. The pattern of incidence of febrile episodes varied for each ward. A total of 123 non-vaccinated inpatients were tested for elevation of serum hemagglutination inhibition titer to the three subtypes of influenza virus. Of these, 58 (47.2%) patients were infected with at least one of the influenza viruses during the epidemic of 1995. No patient with pre-existing HI titer over 128X was infected with any of three types of influenza, indicating that HI titer over 128X is the protective level. The febrile episode frequency was significantly higher in the non-vaccinees than in the vaccinees (49.6% vs. 32.6%), but it was quite comparable in the two groups after the influenza epidemic (34.9% vs. 35.8%). The number of observed deaths from January to September of 1995 was 4 (4.9%) in the vaccinee group and 12 (9.8%) in the non-vaccinee group. These results suggest that influenza epidemics have a striking impact on geriatric inpatients and that influenza vaccination has significant efficacy for the reduction of harmful events associated with influenza infection.

Aged↗
PubMed1998

[Antibody response to a single injection of influenza vaccine among geriatric inpatients vaccinated annually].

To determine the efficacy of a single influenza vaccine administration in the elderly receiving annual influenza vaccination, antibody response to influenza vaccine was compared between once and twice injections in a geriatric cohort. Influenza vaccination had been done for 69 inpatients in the year prior to the study, and was administered twice for 34 of them and once for the other 35 during the study period. Influenza vaccine was injected twice to 77 inpatients who had not received influenza vaccine in the year prior to the study. Hemoagglutination inhibition (HI) antibody titer for influenza A/H1N1, A/H3N2, and B was measured before vaccination, after the first vaccination, after the second vaccination, and after the epidemic period, September 1995 to April 1996. HI antibody titer prior to vaccination was significantly higher in the patients who had received influenza vaccination the previous year. The influenza vaccine induced an increase in HI titer in almost all subjects, and the geometric mean of the HI titer after vaccination in the patients who received vaccine once was comparable to that of the patients injected vaccine twice. The number of patients with HI titers of over 128x increased, and the frequency ranged from 60.0% to 97.1% for the influenza viruses of the three subtypes. The frequency of HI titers over 128x was not significantly different among the three groups. The second vaccination did not increase the number of patients with HI titers over 128x when compared with the number after the first injection in the patients who had received influenza vaccine the previous year. These results suggest that prior vaccination does not diminish the antibody response to influenza vaccine in the elderly. The efficacy of a single influenza vaccination is comparable to that achieved by twice injections in the elderly receiving annual influenza vaccination.

Aged↗