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Biomedical subjects

K Yamaji

Publications and source records attributed to K Yamaji.

At least 55 records · Page 3Linked to original sources
PubMed1997

Correlation between human T cell lymphotropic virus type-1 and Strongyloides stercoralis infections and serum immunoglobulin E responses in residents of Okinawa, Japan.

To clarify the relationship between Strongyloides stercoralis, infection with human T cell lymphotropic virus type-1 (HTLV-1), and serum immunoglobulin E (IgE) levels, epidemiologic investigations of these two infections were conducted in inhabitants of Okinawa, a subtropical zone in Japan. Blood and feces samples were taken from 1,347 healthy inhabitants (554 males and 793 females). Antibody to HTLV-1 was measured by particle agglutination, enzyme-linked immunosorbent assay, and Western blotting. The presence of Strongyloides was determined by direct detection of rhabditiform larvae in fresh stool on agar-plate cultures. Serum IgE levels in 127 inhabitants were measured by a fluoroenzyme immunoassay. Antibody to HTLV-1 was detected in 23.0% of the blood samples and was more frequent in females (25.1%) than in males (20.0%) (P < 0.05). Strongyloides were detected in 21.9% of the feces samples and were more frequent in males (31.9%) than in females (14.9%) (P < 0.001). The prevalence of both infections increased with age, especially in persons 50 years of age and older: The prevalence of Strongyloides infection was significantly higher in HTLV-1 carriers (31.6%) than in those without HTLV-1 infection (P < 0.001). The level of IgE was low in HTLV-1 carriers, and significantly lower in HTLV-1 carriers than in noncarriers among inhabitants with Strongyloides infection. Both HTLV-1 and Strongyloides infections are endemic in the area studied.

Adult↗
PubMed1997

Cyclothialidine analogs, novel DNA gyrase inhibitors.

DNA gyrase inhibitors, cyclothialidines B, C, D and E were isolated from four Streptomycete strains (NR 0659, NR 0660, NR 0661 and NR 0662). Their structures have been elucidated based on the amino acid analysis of the hydrolysates, NMR and HRFAB-MS experiments and shown to be cyclothialidine analogs. The absolute stereochemistry has been determined by the chiral HPLC analysis of the hydrolysates. Cyclothialidines B, D and E are novel and potent inhibitors of DNA gyrase.

Chromatography, High Pressure Liquid↗
PubMed1997

Elevation of serum soluble interleukin-2 receptor levels in patients with hepatitis C virus infection.

To determine serum soluble interleukin-2 receptor (sIL-2 R) levels in hepatitis C virus (HCV) infection, serum sIL-2 R was measured in 260 subjects with chronic HCV infection, including 100 patients who had previously been treated with natural interferon (IFN) alpha, and in 51 HCV RNA-negative controls. Serum sIL-2 R levels in asymptomatic HCV carriers, patients with chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC) were significantly higher than those of healthy controls and subjects who were positive for anti-HCV and negative for HCV RNA (P < 0.01, respectively). Moreover, serum sIL-2 R levels were also significantly higher in patients with HCC than in other HCV RNA-positive groups. There was some correlation between serum sIL-2 R levels and histological activity index scores (r = 0.287, P < 0.01) and serum alanine aminotransferase levels (r = 0.272, P < 0.01). In patients in whom HCV RNA was eliminated following IFN treatment, serum sIL-2 R levels decreased to those seen in healthy controls by one year post treatment. Serum sIL-2 R levels increase due to HCV infection, and the amount of increase corresponds to the degree of inflammation.

Carrier State↗
PubMed1996

Simultaneous determination of uric acid and creatinine in biological fluids by column-switching liquid chromatography with ultraviolet detection.

A column-switching liquid chromatographic method for the simultaneous determination of uric acid and creatinine in human serum and urine was developed. Creatinine and uric acid were separated by size-exclusion chromatography on a hydrophilic gel column (C1) and creatinine eluted from C1 was separated from proteins by filtration through a longer hydrophilic gel column (C2). The creatinine fraction eluted from C2 was transferred to a weakly acidic cation-exchange column (C3) and then to a strongly acidic cation-exchange column (C4). Uric acid eluted from C1 after creatinine was transferred to an anion-exchange column (C5) and then to a hydrophilic gel column (C6). The mobile phase was a mixed buffer of pH 5.1 (propionic acid-succinic acid-NaOH, 60:15:60 mmol/l in water). Diluted serum and urine could be injected onto C1, and C1 was backflushed after the transfer of uric acid from C1 to C5. Creatinine and uric acid in the eluate were determined by measuring their ultraviolet absorption at 234 and 290 nm, respectively. The recovery of uric acid and creatinine added to diluted serum (20-fold dilution, concentration 20 and 5 mumol/l, respectively) was 98.9 +/- 0.56% and 100.9 +/- 1.29%, respectively. The recovery of uric acid and creatinine added to diluted urine (100-fold dilution, concentration 50 and 100 mumol/l, respectively) was 99.4 +/- 0.72% and 98.7 +/- 1.45%, respectively (mean +/- R.S.D., n = 6).

Chromatography, Gel↗
PubMed1996

IL-1 beta and TNF-alpha produced by peripheral blood mononuclear cells before and during interferon therapy in patients with chronic hepatitis C.

We investigated the spontaneous and phytohemagglutinin-stimulated production of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) by peripheral blood mononuclear cells in patients with chronic hepatitis C during treatment with interferon-alpha (IFN-alpha). Spontaneous productions of these were significantly higher in patients with chronic hepatitis C than in healthy subjects. For patients prescribed interferon, stimulated production of TNF-alpha was significantly higher in complete responders than in partial responders, but the differences were small between the other cytokine levels and outcome of IFN treatment. Spontaneous production of these cytokines was higher in patients with genotype III with complete response than in genotype III patients with a partial response, but this was not the case in patients with genotype II. There was a negative correlation between these cytokines and histological activity index. Spontaneous production of cytokines was decreased only in complete responders after the administration of interferon. These data suggest that the elevated production of cytokines in patients with chronic hepatitis C may be due to host response to the virus, and monitoring cytokines along with alanine aminotransferase and hepatitis C virus RNA during treatment may provide more precise information of the effectiveness of therapy.

Adult↗
PubMed1996

Evaluation of quantitative assay for antibody to hepatitis C virus core in patients treated with interferon.

We titrated antibody to hepatitis C virus (anti-HCV) core of serum samples from 57 patients with chronic HCV infection, in an attempt to clarify the relationship between the level of HCV RNA and the outcome of interferon treatment. The patients studied were positive for both anti-HCV, by second-generation assay, and HCV RNA, by polymerase chain reaction, and had been treated with interferon for six months. Of the 57 patients, HCV RNA was eliminated in 16 by the time of discontinuation of interferon treatment (CR); in 19 this elimination was transient (PR) and for 22 elimination was nil (NR). The low HCV RNA level was accompanied by high titers of anti-HCV core while high HCV RNA levels were accompanied by low titers of anti-HCV core, with an inverse correlation (r = -0.322, P < 0.05). The mean titer of anti-HCV core before interferon treatment was 324 units in CR, 205 in PR, and 168 in NR, with a correlation ratio of 0.382 (P < 0.05). A decreased titer (more than 50%) was found in 68% of the CR. At the time of six-month follow-up, the anti-HCV core titers of CR had decreased by more than 50%, compared to pretreatment titers, while in PR and NR, there was an increase to above the pretreatment titers, without increases in HCV RNA levels or worsening of the hepatitis. In conclusion, quantitative assay for anti-HCV core is useful to assess the status of HCV replication.

Adult↗
PubMed1996

Establishment of an in vitro assay system for screening hepatitis C virus protease inhibitors using high performance liquid chromatography.

The hepatitis C virus (HCV) genome contains the code for a conserved, serine-type protease, called NS3, for the processing of the non-structural protein region of the viral polyproteins. Furthermore, a related protein, NS4A, is an effector or cofactor of NS3 protease activity in the cleavage of NS3-4A, NS4A-4B, NS4B-5A and NS5A-5B junctions. To establish an in vitro assay system for the screening of those enzyme inhibitors that inhibit the protease NS3-4A, we prepared a maltose-binding protein-NS3-NS4A fusion protein and a synthetic peptide substrate that mimics the NS5A-5B junction. Cleavage of the synthetic peptide was analyzed by reversed-phase high performance liquid chromatography (HPLC). We showed that the enzymatic activity of the NS3-NS4A fusion protein was enhanced in comparison to the NS3 protein alone. The assay conditions for optimum NS3-4A protease activity were determined to be pH 7.6 and 37 degrees C. In addition, we evaluated several protease inhibitors using the same HPLC assay system. The activity of HCV protease NS3-4A was inhibited by 2714.4 microM diisopropyl fluorophosphate, 270.8 microM N-tosyl-L-lysyl chloromethyl ketone, and 825.5 microM chymostatin. The results of the present study indicated that the synthetic peptide substrate and HPLC assay system are suitable for studying HCV protease activity and may facilitate the development of anti-HCV therapeutic reagents.

Amino Acid Sequence↗
PubMed1996

[Incidence and duration of febrile episodes in a hospitalized geriatric cohort].

Fever is a common and important clinical symptom observed among hospitalized geriatric patients. To investigate the frequency and duration of fever episodes, we surveyed fever episodes in a hospital where the frequency of patients over 60 years of age exceeds 90 per cent of the patients. Fever episodes with body temperature of over 37.5 degrees C were registered from May in 1991 to December in 1994, and 6809 episodes were subjected to analysis. The average incidences per month were 157.1, 165.3, 158.0, and 139.3 in 1991, 1992, 1993, and 1994, respectively. The numbers of episodes per month did not show any significant correlation with temperature or humidity. Average duration of the episodes were 8.0, 6.5, 7.6, and 6.7 days for 1991, 1992, 1993, and 1994, respectively. Episodes of one day duration were the most frequent in all months, and the frequencies of that ranged from 37.1% to 58.6% with a mean of 47.8%. The average duration of episodes and the frequency of one day episodes did not change significantly irrespective of a notable decrease in the total incidence. The high frequency of one day episodes and their consistency through the observed period suggest that fevers with one day duration are one of the characteristic features of the febrile symptoms in geriatric patients. Causality and prevention methods for these one day fever episodes should be investigated.

Aged↗
PubMed1996

[Serum albumin level as a predictor of incidence of febrile episodes and mortality in hospitalized geriatric patients].

To investigate the relationship between serum albumin level and incidence of febrile episodes and mortality in the elderly, we studied 748 patients hospitalized for over one year. The subjects included 123 males and 355 females with a mean age 81.2 years. The average serum albumin level was 3.79 g/dl and levels of serum albumin decreased with advancing age. The incidence of febrile episodes was 1.8 per year in patients with serum albumin levels over 4.1 g/dl, increasing with decline of serum albumin levels. The incidence of febrile episodes was 5.3 per year in patients with serum albumin levels under 3.0 g/dl. Patients with serum albumin levels under 3.0 g/dl displayed a high incidence of febrile episodes irrespective of age. Age adjusted in-hospital mortality was 40.4% during the observed period in patients with serum albumin levels under 3.0 g/dl, significantly higher than that of the patients with serum albumin levels over 3.1 g/dl. Relative risk of febrile episode and mortality calculated using the patients with serum albumin levels over 4.1 g/dl as a control was 2.9 and 2.1, respectively, in the patients with serum albumin levels under 3.0 g/dl. These results indicate that serum albumin level is a simple, but strong, predictor of susceptibility of febrile episode and death. Patients with serum albumin levels under 3.0 g/dl may constitute a high risk group for febrile episode and death.

Aged↗
PubMed1996

Identification of the sequence on NS4A required for enhanced cleavage of the NS5A/5B site by hepatitis C virus NS3 protease.

In addition to NS3 protease, the NS4A protein is required for efficient cleavage of the nonstructural protein region of the hepatitis C virus polyprotein. To investigate the function and the sequence of NS4A required for the enhancement of NS3 protease activity, we developed an in vitro NS3 protease assay system consisting of three purified viral elements: (i) a recombinant NS3 protease which was expressed in Escherichia coli as a maltose-binding protein-NS3 fusion protein (MBP-NS3), (ii) synthetic NS4A fragments, and (iii) a synthetic peptide substrate which mimics the NS5A/5B junction. We showed that the NS3 protease activity of MBP-NS3 was enhanced in a dose-dependent manner by 4A18-40, which is a peptide composed of amino acid residues 18 to 40 of NS4A. The optimal activity was observed at a 10-fold molar excess of 4A18-40 over MBP-NS3. The coefficient for proteolytic efficiency, kcat/Km, of NS3 protease was increased by about 40 times by the addition of a 10-fold molar excess of 4A18-40. Using a series of truncations of 4A18-40, we estimated that amino acid residues 22 to 31 in NS4A (SVVIVGRIIL) constituted the core sequence for the effector activity. Single-substitution experiments with 4A21-34, a peptide composed of amino acid residues 21 to 34 of NS4A, suggested the importance of several residues (Val-23, Ile-25, Gly-27, Arg-28, Ile-29, and Leu-31) for its activity. In addition, we found that some single-amino-acid substitutions in 4A21-34 were able to inhibit the enhancement of NS3 protease activity by 4A18-40. This approach has potential as a novel strategy for inhibiting the NS3 protease activity important for hepatitis C virus proliferation.

Amino Acid Sequence↗
PubMed1996

Long term survey of hepatitis C virus infection in hemodialysis units in Fukuoka, Japan.

To examine prevalence of hepatitis C virus (HCV) infection and liver dysfunction in hemodialysis units, we surveyed markers for HCV infection and serum alanine aminotransferase (ALT) in hemodialysis patients. 204 hemodialysis patients (111 men and 93 women; mean age, 53 +/- 12 years) in four hemodialysis units in Fukuoka, Japan were investigated. All serum samples were tested for antibody to HCV (anti-HCV) by second-generation enzyme-linked immunosorbant assay (ELISA). HCV RNA was detected to identify present HCV infection in the anti-HCV-positive patients by polymerase chain reaction (PCR) using primers deduced from the 5'-noncoding region. Liver dysfunction was defined as an elevated concentration of serum ALT (above 36 IU/liter) tested by a multiple autoanalyser. 105 patients (51.5 percent) were initially positive for anti-HCV, 95 (90.5 percent) of whom were also positive for HCV RNA. Ten became positive for anti-HCV in hemodialysis units during the observation, eight (80 percent) of whom had sustained HCV viremia. The route of transmission of HCV was not clear, but two of these patients had received blood transfusions. Of 95 patients with HCV viremia, 43 (45.3 percent) had had liver dysfunction at least once. In conclusion, HCV infection continues to occur in hemodialysis units not through blood transfusion and many of them become HCV carriers. Liver dysfunction was found in about a half of HCV-infected hemodialysis patients during the observation.

Adult↗
PubMed1996

Hepatitis C virus RNA levels determined by branched DNA probe assay correlated with levels assessed using competitive PCR.

OBJECTIVE: To search for comparative differences, levels of hepatitis C virus (HCV) RNA were examined by branched DNA (bDNA) probe assay and by competitive polymerase chain reaction (PCR). METHODS: The study population included 234 patients (chronic hepatitis 146, cirrhosis 36, hepatocellular carcinoma 52), all of whom were positive for HCV RNA, as determined by PCR. We quantified HCV RNA levels of all serum samples by both bDNA probe and competitive PCR. RESULTS: HCV RNA was detected in serum samples by bDNA assay in 142 (60.7%) of the 234 patients; this rate was significantly higher in 106 (73.6%) of the 144 patients in genotype II than in 20 (41.7%) of 48 of genotype III and in 16 (38.1%) of 42 of genotype IV (p < 0.001, respectively). The median HCV RNA levels by bDNA assay (x 10(6) eq/ml) were 0.1, 0.1, 0.4, 1.4, and 5.3 among patients with HCV RNA levels < 3, 4, 5, 6, and 7 respectively, by competitive PCR (logarithmic transformation copy numbers/50 microliters). A significant correlation was found between HCV RNA levels by bDNA and competitive PCR (r = 0.5747, p < 0.001). There was a correlation among patients of genotype II and genotype III but not genotype IV. CONCLUSION: We recommend bDNA assay for use in clinical practice because the procedure is not difficult and is less contamination-prone. The HCV RNA levels determined using this assay correlated with those examined by competitive PCR.

Base Sequence↗
PubMed1995

Structure-activity relationship of alpha-galactosylceramides against B16-bearing mice.

Agelasphin-9b, (2S,3S,4R)-1-O-(alpha-D-galactopyranosyl)-16-methyl-2- [N-((R)-2- hydroxytetracosanoyl)-amino]- 1,3,4-heptadecanetriol, is a potent antitumor agent isolated from the marine sponge Agelas mauritianus. Various analogues of agelasphin-9b (a lead compound) were synthesized, and the relationship between their structures and biological activities was examined using several assay systems. From the results, KRN7000, (2S,3S,4R)-1-O-(alpha-D- galactopyranosyl)-2-(N-hexacosanoylamino)-1,3,4-octadecanetriol , was selected as a candidate for clinical application.

Animals↗
PubMed1995

A human erythrocyte-derived growth-promoting factor with a wide target cell spectrum: identification as catalase.

We have reported previously that a factor with a molecular weight of 53,000 under SDS-polyacrylamide gel electrophoresis purified from human erythrocyte extracts promoted the growth of a wide variety of cell types from different species, including T cells, B cells, myeloid leukemia cells, melanoma cells, and mastocytoma cells, as well as normal and transformed fibroblast cells. In the present study, amino acid sequence analysis revealed that this factor has homology with human catalase. The purified factor exhibited catalase activity. Catalases derived from human erythrocytes, bovine liver, Aspergillus niger, and recombinant rat liver catalase are all able to promote the growth of cells. Antibody against human catalase absorbed both the growth-promoting activity and the enzyme activity of the purified factor. In addition, treatment of the factor with an irreversible enzyme inhibitor, aminotriazole, resulted in abrogation of both the growth-promoting activity and enzyme activity. These results indicate that the growth-promoting factor is catalase, and its activity is associated with the decomposition of hydrogen peroxide.

Amino Acid Sequence↗
PubMed1995

Antibody to annexin V has anti-phospholipid and lupus anticoagulant properties.

Anti-annexin V (anti-ANXV) IgG and lupus anticoagulant (LAC) were both shown to be capable of inducing apoptosis in umbilical vein endothelial cells [Nakamura et al.: Biochem Biophys Res Commun 205:1488-1493, 1994]. In the present study, we have demonstrated that anti-ANXV IgG prolongs the activated partial thromboplastin time and has an affinity for phospholipids in enzyme-linked immunosorbent assay. This indicates overlapping of anti-ANXV and LAC activities, suggesting that ANXV may be involved in the autoimmune mechanism for LAC production.

Animals↗
PubMed1995

Serum levels of soluble interleukin-2 receptors and effects of interferon-alpha for patients with chronic hepatitis C virus.

To characterize the role of serum soluble interleukin-2 receptor (sIL-2R) in hepatitis C virus (HCV) infection, the level of sIL-2R was measured by ELISA in 117 subjects with chronic HCV infection and in 23 healthy controls. HCV RNA was detected by polymerase chain reaction in all subjects with HCV infection. Forty-seven patients with chronic hepatitis and 10 with liver cirrhosis were treated for six months with natural interferon-alpha. The sIL-2R levels of 40 asymptomatic HCV carriers (632 +/- 340 units/ml), 47 patients with chronic hepatitis (547 +/- 204 units/ml), 10 with cirrhosis (679 +/- 239 units/ml, and 20 with hepatocellular carcinoma (1145 +/- 487 units/ml) were significantly higher than those of healthy controls (380 +/- 191 units/ml) (P < 0.05, respectively). The levels of sIL-2R increased, as did the histological activity index scores (r = 0.348, P < 0.01). The level of sIL-2R rose after the initial administration of interferon in all 57 patients. In patients whom HCV RNA was eliminated from the sera within a six-month follow-up after cessation of treatment, the level of sIL-2R reverted to basal values, but in patients in whom HCV RNA was not eliminated the value was significantly higher than that before treatment. These results suggest that monitoring serum sIL-2R in patients with chronic HCV infection treated with interferon may provide information concerning the possibility of the elimination of HCV RNA.

Carcinoma, Hepatocellular↗