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Biomedical subjects

K Yamaji

Publications and source records attributed to K Yamaji.

At least 19 recordsLinked to original sources
PubMed2003

Optimization of RNA yield, purity and mRNA copy number by treatment of urine cell pellets with RNAlater.

BACKGROUND: We have shown that measurement of mRNA for cytotoxic attack proteins perforin and granzyme B in urinary cells is a noninvasive means of diagnosing acute rejection of human renal allografts. Urinary cell mRNA studies have yielded useful information in other patient populations such as patients with cancer. The isolation of sufficient and high quality ribonucleic acid (RNA) from urinary cells however is problematic. RNAlater, an RNA stabilization solution, has been reported to optimize RNA isolation from tumor tissues stored at room temperature and from pigment-rich ocular tissues. METHODS: We explored whether the addition of RNAlater to urine cell pellets improves RNA yield, enhances purity and facilitates measurement of low abundance mRNAs. We measured, with the use of real-time quantitative polymerase chain reaction (PCR) assay, levels of expression of a constitutively expressed gene 18S rRNA and mRNA for granzyme B and transforming growth factor-beta(1) (TGF-beta(1)) in urine specimens and renal biopsies obtained from renal allograft recipients. RESULTS: RNA yield (P<0.01, Wilcoxon signed rank test) and the A260/A280 ratio (P<0.01) were both higher with urine cell pellets treated with RNAlater prior to snap freezing compared to cell pellets that were not treated with RNAlater prior to snap freezing. Levels (copy number per 1 microg of total RNA) of 18S rRNA (P<0.02), granzyme B mRNA (P=0.002) and TGF-beta(1) (P=0.02) were all higher with treated urine cell pellets compared to untreated cell pellets. Kruskall-Wallis one way analysis of variance and pair-wise comparisons with Student-Newman-Keuls test showed that the levels of mRNA for granzyme B (P<0.05) and TGF-beta(1) (P<0.05) are significantly different between renal allograft biopsies and untreated urine cell pellets but not between the biopsy specimens and RNAlater-treated urine cell pellets. CONCLUSIONS: The addition of RNAlater to urine cell pellets improves RNA isolation from urinary cells and facilitates measurement of low abundance mRNAs.

Adolescent↗
PubMed2003

Age-related accumulation of Ig V(H) gene somatic mutations in peripheral B cells from aged humans.

To investigate age-related alterations in human humoral immunity, we analysed Ig heavy chain variable region genes expressed by peripheral B cells from young and aged individuals. Three hundred and twenty-seven cDNA sequences, 163 micro and 164 gamma transcripts with VH5 family genes, were analysed for somatic hypermutation and VHDJH recombinational features. Unmutated and mutated micro transcripts were interpreted as being from naive and memory IgM B cells, respectively. In young and aged individuals, the percentages of naive IgM among total micro transcripts were 39% and 42%, respectively. D and JH segment usage in naive IgM from aged individuals was similar to that from young individuals. The mutational frequencies of memory IgM were similar in young and aged individuals. gamma transcripts, which are regarded as being from memory IgG B cells, showed a significantly higher mutational frequency (7.6%) in aged than in young individuals (5.8%) (P < 0.01). These findings suggest that VHDJH recombinational diversity was preserved, but that the accumulation of somatic mutations in the IgG VH region was increased in aged humans. The accumulation of somatic mutations in IgG B cells during ageing may imply that an age-related alteration exists in the selection and/or maintenance of peripheral memory B cells.

Adult↗
PubMed2002

The effectiveness of intravenous human immunoglobulin treatment after plasmapheresis in restoring serum immunoglobulin levels: a preliminary study.

This study was performed to examine the effects of intravenous human immunoglobulin (IVIG) on the level of serum immunoglobulin G (IgG) and its subclasses after plasmapheresis in patients with autoimmune disorders. Twenty-nine patients with predominantly rheumatoid arthritis were enrolled in this study. The plasmapheresis was performed by the use of double-filtration plasmapheresis (DFPP). Immediately after DFPP, IVIG (2.5 g, 50 ml) was intravenously administered. The treatment with IVIG had almost no effect on subjective and objective symptoms. Immediately after DFPP, the total of serum IgG was decreased by approximately 40%. After 24 h, the total of serum IgG recovered to 16% reduction in IVIG-treated patients whereas it remained at 32% reduction in nontreated patients. The beneficial effect of IVIG was significantly observed in patients who had shown 1,000-1,800 mg/dl IgG in their sera. After DFPP, IgG subclasses were decreased without change in the ratio of subclasses. Twenty percent to 30% of IgG subclasses were supplemented by the treatment with IVIG without change in the ratio of subclasses. These results suggested that the treatment with IVIG at minimal amount was safe and effective to supplement IgG for hypogammaglobulinemia after DFPP.

Adult↗
PubMed2001

Evidence of B cell clonal expansion in HIV type 1-infected patients.

HIV-1 infection results in a gradual decrease in CD4(+) T cell counts and progressive immune deficiency. Increased T cell turnover in HIV-1-infected patients, which can be interpreted as T cell clonal expansion, has been thought to be relevant to its pathogenesis. To investigate whether B cell clonal expansion also occurs in HIV-1-infected patients, we examined the expressed V(H)DJ(H) gene sequences of peripheral B cells in HIV-1-infected patients with hypergammaglobulinemia. Identical V(H)DJ(H) gene rearrangements with additional nucleotide differences in V(H) genes were analyzed as a marker of clonally related B cells. From healthy individuals and HIV-1-uninfected patients with hypergammaglobulinemia, clonally related B cells were detected in none of 10 (0%) and 2 of 10 (20%), respectively. No clonally related B cells were detected in any of the nine HIV-1-infected patients with detectable viral loads and normal Ig levels (0%). In contrast, from 9 of 14 HIV-1-infected patients with hypergammaglobulinemia (64%), clonally related B cells were detected. In addition, no HIV-1-infected patients who exhibited normal Ig levels after antiretroviral therapy had clonally related B cells. These findings suggest that B cell clonal expansion is present in HIV-1-infected patients with hypergammaglobulinemia.

Adult↗
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↗
PubMed2001

Current topics on cytapheresis technologies.

Cytapheresis has been investigated recently for the treatment of autoimmune related diseases, such as rheumatoid arthritis (RA), inflammatory bowel disease (IBD), multiple sclerosis, and so on. A large number of physicians have indicated that patients with autoimmune diseases respond to cytapheresis treatment. The effective mechanism of cytapheresis for immune disorders is still controversial. However, the removal of the leukocyte including granulocyte, lymphocyte, and monocyte may play a crucial role in correcting imbalance of the immune system. A session of cytapheresis including leukocytapheresis (LCAP) and granulocytapheresis (GCAP) may not create a sufficient amount of cell removal for the human body. However, the cell removal can be a trigger of the immunomodulation as the treatment for immune disorder. Furthermore, not only cell removal but also reaction by blood contacting with medical device materials may play a role as an immunomodulation for immune disorders. This review introduces current cytapheresis technologies and attempts to elucidate the effective mechanism of cytapheresis for immune disorders, focused on LCAP and/or GCAP for RA or IBD.

Arthritis, Rheumatoid↗
PubMed2001

Myocardial ultrasonic tissue characterization for estimating histological abnormalities in hypertrophic cardiomyopathy: comparison with endomyocardial biopsy findings.

AIMS: In this study, we investigated the clinical usefulness of ultrasonic tissue characterization with integrated backscatter for the evaluation of myocardial histological abnormalities in comparison with endomyocardial biopsy findings in patients with hypertrophic cardiomyopathy. METHODS: Twenty patients with hypertrophic cardiomyopathy and 20 normal subjects were enrolled in this study. We measured two parameters for the ultrasonic tissue characterization with integrated backscatter: the magnitude of the cardiac-cycle-dependent variation in integrated backscatter signals (cdv-IB) and the mean value of integrated backscatter signals calibrated by the pericardium (cal-IB). These parameters were measured at both the interventricular septum and the left ventricular posterior wall. Histological findings of right ventricular endomyocardial biopsy specimens were analyzed by computer image analyzer. RESULTS: cdv-IB was significantly lower and cal-IB significantly higher in both the interventricular septum and the left ventricular posterior wall in patients with hypertrophic cardiomyopathy compared with normal subjects. In patients with hypertrophic cardiomyopathy, the degree of myocardial disarray, interstitial fibrosis, and nonhomogeneity of myocyte size showed positive correlations with cal-IB and negative correlations with cdv-IB. CONCLUSIONS: Ultrasonic tissue characterization with IB enables the noninvasive evaluation of myocardial histological abnormalities in patients with hypertrophic cardiomyopathy.

Adult↗
PubMed2001

[Therapeutic plasmapheresis for the prevention of congenital complete heart block associated with anti-SS-A/Ro antibody and anti-SS-B/La antibody].

OBJECTIVES: Neonatal lupus erythematosus is characterized by transient lupus abnormalities, various systemic and hematological abnormalities, and congenital complete heart block (CCHB). It is well known that anti-SS-A/Ro antibody (52 kD/60 kD) and anti-SS-B/La antibody are associated with CCHB. This study was conducted to evaluate the effects of the removal of anti-SS-A/Ro antibody (52 kD/60 kD) and anti-SS-B/La antibody from plasma in pregnant women whose fetuses are at a high risk of developing CCHB. MATERIALS & METHODS: Fifteen pregnant patients positive for anti-SS-A/Ro antibody and anti-SS-B/Laantibody were subjected weekly to double filtration plasmapheresis to remove both antibodies. Antibody titers were measured by double immunodiffusion (DID) and ELISA. RESULTS: As a result, all women gave birth to live babies, but CCHB was recognized in one baby. No transient lupus abnormalities were recognized in any of the babies. Fourteen patients showed decreased antibody titers by ELISA during plasmapheresis. However, the patient who was delivered of a baby with CCHB showed an increase of antibody titers by ELISA while the DID method showed a decrease of antibody titers. CONCLUSION: Our study suggested that plasmapheresis prevents CCHB associated with anti-SS-A/Ro and anti-SS-B/La antibody. Also, it is important to monitor the antibody titer regularly during the course of pregnancy, because it may increase due to worsening of the mother's primary disease.

Adult↗
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↗