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Biomedical subjects

Masaru Nasu

Publications and source records attributed to Masaru Nasu.

At least 55 records · Page 3Linked to original sources
PubMed2003

Natural killer cell-type body cavity lymphoma following chronic active Epstein-Barr virus infection.

We describe a 69-year-old female who developed natural killer cell-type body cavity lymphoma following chronic active Epstein-Barr virus (CAEBV) infection. Examination of the patient's pleural effusion revealed large abnormal lymphocytes, which were CD2(+), CD7(+), CD30(+), CD56(+), CD3(-), and CD4(-). No rearrangement of T cell receptor genes was detected. Clonal proliferation of Epstein-Barr virus (EBV)-infected cells in pleural effusion was demonstrated by Southern blot hybridization analysis. Human herpesvirus type-8 (HHV-8) DNA was not detected in these cells. The patient achieved a complete remission with combination chemotherapy. Prior to the clinical onset of lymphoma, high fever of unknown origin had persisted for 21 months. IgG antibodies to EBV-viral capsid antigen and to EBV-early antigens, types D and R were not high (1:160 and less than 1:10, respectively). Two months after the onset of fever, however, retrospective quantitative PCR assay revealed a high EBV DNA load in plasma, indicating that CAEBV infection had been the cause of the patient's recurrent fever. The remarkable features of this case are (i) the development of lymphoma following CAEBV infection that demonstrated a normal pattern of EBV-specific antibodies, (ii) the development of HHV-8-negative body cavity lymphoma, and (iii) the effectiveness of combination chemotherapy.

Aged↗
PubMed2003

Influence of anti-ulcer drugs used in Japan on the result of (13)C-urea breath test for the diagnosis of Helicobacter pylori infection.

BACKGROUND: The (13)C-urea breath test (UBT) is a simple breath test for the diagnosis of Helicobacter pylori infection, but several factors have been reported to affect the results of this test. In this study, the effects of the antiulcer drugs used in Japan on the results of UBT were determined. METHODS: The subjects of the study were 64 adult volunteers who tested positive for H. pylori infection by the serum antibody method. Eight classes of anti-ulcer drugs used in Japan were administered at their usual doses to these subjects: lansoprazole, a proton pump inhibitor (PPI); nizatidine, an H(2)-receptor antagonist (H(2)RA); and polaprezinc, ecabet sodium, rebamipide, teprenone, cetraxate hydrochloride, and sucralfate, all mucoprotective agents. The study drugs were randomized for administration to the subjects, and each of the drugs was administered for 14 consecutive days. The UBT was performed on days 0, 14, and 21. RESULTS: The mean Delta(13)C per thousand in the lansoprazole group was significantly decreased on day 14, to below 10 per thousand, in 4 of 16 subjects, and in 1 of the 4 subjects, the test result was negative, with the Delta(13)C per thousand falling to 1.7 per thousand. The value returned to baseline 1 week after the discontinuation of lansoprazole. The other drugs administered had no significant effect on the result of the UBT, except that the mean Delta(13)C per thousand showed a tendency to decrease after the administration of ecabet sodium and rebamipide. CONCLUSIONS: Administration of a PPI may produce a false-negative UBT result, while other anti-ulcer drugs, for the most part, have little effect on the result of the UBT when used alone. The (13)C-urea breath test (UBT) is a simple test for the diagnosis of Helicobacter pylori infection, but several factors have been reported to affect the results of this test. In this study, the effects of the anti-ulcer drugs used in Japan on the results of the UBT were determined.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2003

Treatment with rokitamycin suppresses the lethality in a murine model of Escherichia coli O157:H7 infection.

The effects of rokitamycin (ROK) and levofloxacin (LEVX) were investigated in a murine model of enterohaemorrhagic Escherichia coli (EHEC) infection. After C3H/HeN mice were inoculated intragastrically with E. coli O157:H7, ROK (20mg/kg) or LEVX (1.2 mg/kg) was administered intragastrically. The death rate of the mice was noted and the faeces were collected to determine viable cell counts of EHEC and for Shiga-like toxins (SLTs) assays. After the mice were sacrificed, the kidneys and colons of some of the mice were removed for histopathological examination. The death rate of mice administered ROK (19%) was significantly lower than that of the control and LEVX-treated groups (80, 93%, respectively). Viable cell counts of EHEC in the faeces of the control and ROK-treated groups were 10(7) and 10(6) CFU/g at day 5 after the infection, respectively. LEVX reduced the bacterial count by less than 100 CFU/g at day 5. The level of SLTs in the faeces from the ROK group were lower than the LEVX-treated and control groups at day 5. The histopathological findings in the kidneys treated with LEVX showed necrotic tubular epithelial cells and those in the colon, inflammatory infiltrates. These were not seen in the ROK-treated group. These results suggested that ROK suppressed release of SLTs from the EHEC and could be useful in the treatment of EHEC infection.

Animals↗
PubMed2003

Is the recurrence of Helicobacter pylori infection after eradication therapy resultant from recrudescence or reinfection, in Japan.

BACKGROUND: Reinfection of Helicobacter pylori after eradication is rare in developed countries but most often occurs within 1 year. In the present study, we attempted to differentiate between reinfection and recrudescence of H. pylori strains between 6 months and 6 years after successful eradication in Japan, a country with a high prevalence of H. pylori infection. MATERIALS AND METHODS: After successful eradication of H. pylori, 274 patients were followed up by endoscopy and urea breath test. In recurrent patients, H. pylori strains isolated initially and after recurrence were compared using PCR-based restriction fragment length polymorphism (RFLP) analysis. RESULTS: Recurrence of H. pylori occurred in 15 of 274 patients (5.5%) at 6 months after eradication and the annual recurrence rate was 2.0% per patient year (between 1 and 6 years). PCR-based RFLP analysis of H. pylori strains isolated initially and after recurrence showed that 62.5% (at 6 months) and 100% (after 1 years) of bacteria were of different strains. CONCLUSION: Reinfection of H. pylori was not as rare at 6 months after eradication as reported previously, and up to 6 years after eradication, the annual reinfection rate is 2.0% per patient year in Japan.

Adult↗
PubMed2003

Clindamycin modulates inflammatory-cytokine induction in lipopolysaccharide-stimulated mouse peritoneal macrophages.

We investigated the mechanism by which clindamycin (CLI) modulates cytokine induction after lipopolysaccharide (LPS) stimulation. Although CLI decreased the intracellular expression levels of tumor necrosis factor alpha and interleukin 1beta (IL-1beta) and increased IL-6 expression in macrophages, cytokine mRNA expression levels were similar in CLI-treated and untreated groups. Our findings suggest that CLI modulates cytokine production in LPS-stimulated macrophages.

Animals↗
PubMed2003

Real-time PCR assay compared to nested PCR and antigenemia assays for detecting cytomegalovirus reactivation in adult T-cell leukemia-lymphoma patients.

We analyzed the efficiency of the quantitative real-time PCR assay for cytomegalovirus (CMV) reactivation in adult T-cell leukemia-lymphoma (ATL) patients and compared the results with those obtained with qualitative nested PCR and antigenemia assays. The viral load obtained by the real-time PCR assay closely paralleled the number of antigen-positive cells obtained with the antigenemia assay. Real-time PCR revealed that a large number of DNA copies could be present even in samples assessed as negative or low in antigen-positive cells (0 to 10 antigen-positive cells/50,000 cells) by antigenemia assay. CMV copy numbers did not differ between the negative and low-antigen-positive groups. When the input concentration for real-time PCR assay was 2,500 to 5,000 copies/ml, the positivity rate for the nested PCR assay was 47.3%, while the positivity rate was more than 90% at an input concentration of >/=50,000 copies/ml. Real-time PCR is more sensitive than the antigenemia and nested PCR assays. Moreover, real-time PCR was able to detect CMV reactivation earlier than the antigenemia and nested PCR assays through the use of longitudinal analysis in four ATL patients with CMV pneumonia. In longitudinal assessments, analysis of the results suggested that a cutoff level of 5,000 copies/ml might be used to initiate treatment. Real-time PCR is more suitable for monitoring CMV reactivation in ATL patients than the antigenemia and nested PCR assays. CMV viral loads of 5,000 copies/ml are proposed as the cutoff for initiating antiviral therapy in ATL patients.

Adult↗
PubMed2003

Relationship between heart rate variability and left ventricular remodeling after reperfused first anterior wall acute myocardial infarction.

The aim of the present study was to test the hypothesis that inadequate improvement in heart rate variability (HRV) in the healing stage of acute myocardial infarction (AMI) is associated with left ventricular (LV) remodeling. The study group comprised 20 patients (14 men, 6 women; mean age, 61+/-12 years) with a reperfused first anterior AMI (</=24 h). The standard deviation of normal RR intervals (SDNN) was calculated from the 24-h ambulatory electrocardiogram recorded on day 3 of admission and at predischarge from the hospital. Left ventriculography was performed immediately after primary angioplasty and at predischarge. The change in SDNN (deltaSDNN) was compared with the change in the LV end-systolic volume index (deltaLVESVI), a parameter of LV remodeling. SDNN increased from 73+/-19 ms on day 3 to 109+/-35 ms at predischarge (p=0.0003). SDNN at predicharge and deltaSDNN correlated negatively with deltaLVESVI (r=-0.52, p=0.02, and r=-0.61, p=0.004, respectively), whereas SDNN on day 3 did not correlate with deltaLVESVI. Multiple regression analysis selected deltaLVESVI (p=0.02) as an independent factor of deltaSDNN. This study indicates that deltaSDNN and SDNN at predicharge are associated with deltaLVESVI in patients with a reperfused first anterior wall AMI, indicating that persistently reduced HRV is associated with postinfarction LV remodeling.

Aged↗
PubMed2003

Osteopontin is released from the heart into the coronary circulation in patients with a previous anterior wall myocardial infarction.

The present study was designed to clarify whether osteopontin, an extracellular matrix protein, is released from the heart into the coronary circulation in patients with a previous (>3 months) anterior wall myocardial infarction (MI). Using a commercially available enzyme immunoassay kit, plasma concentrations of osteopontin were measured in 30 patients (26 men, 4 women; mean age, 61+/-12 years). Blood samples were obtained from the aortic root and coronary sinus. The difference in the plasma concentrations of osteopontin in the aortic root and coronary sinus, which reflects the cardiac production of osteopontin released into the coronary circulation, was compared with the left ventricular ejection fraction (LVEF) and volumes obtained from contrast left ventriculography. Plasma osteopontin concentrations were significantly higher in the coronary sinus than in the aortic root (672+/-446 vs 610+/-398 ng/ml, p=0.02). The transcardiac gradient of plasma osteopontin concentration correlated negatively with LVEF (r=-0.55, p=0.0005) and positively with left ventricular (LV) end-diastolic (r=0.63, p=0.0001) and end-systolic volume indexes (r=0.79, p<0.0001). This is the first study to show that in patients with a previous anterior wall MI osteopontin is released from the heart into the coronary circulation in proportion to the LV systolic function and volumes, suggesting that this extramatrix protein is associated with post-MI LV remodeling.

Aged↗
PubMed2003

Effects of atorvastatin and pravastatin on malondialdehyde-modified LDL in hypercholesterolemic patients.

The aim of the present study was to compare the effects of atorvastatin and pravastatin on lipid parameters and the concentration of malondialdehyde-modified low-density lipoprotein (MDA-LDL) in hypercholesterolemic patients. A total of 17 patients (10 men, 7 women; mean age, 68+/-9 years) who were indicated for drug therapy based on the National Cholesterol Education Program II underwent an 8-week regimen of atorvastatin (10 mg/day) or pravastatin (10 mg/day) with a 4-week washout period between drugs. After an overnight fast, lipid parameters and MDA-LDL concentration were measured before and after the 8-week treatment with each drug. Both atorvastatin and pravastatin produced significant reductions in low-density lipoprotein (LDL) cholesterol and MDA-LDL concentrations, with a significant increase in high-density lipoprotein cholesterol concentration. The percent reductions in LDL cholesterol and MDA-LDL concentration were significantly greater with atorvastatin than pravastatin (46 +/-6% vs 24+/-10%, p<0.0001, and 44+/-10% vs 14+/-13%, p<0.0001, respectively). The ratios of percent reductions in MDA-LDL concentrations and percent reductions in LDL cholesterol concentrations were significantly greater for atorvastatin than pravastatin (0.96+/-0.19 vs 0.59+/-0.55, p<0.0001). In conclusion, atorvastatin reduced serum concentrations of LDL cholesterol and MDA-LDL to a greater degree than pravastatin, indicating that atorvastatin not only has stronger lipid-lowering effects, but also stronger antioxidative effects than pravastatin.

Aged↗
PubMed2003

[Pathogenesis of Trichosporon asahii and strategies for infectious control of disseminated trichosporonosis].

Deep-seated trichosporonosis is a lethal opportunistic infection in immunocompromised patients. Trichosporon asahii and T. mucoides are the most common strains of fungi that cause disseminated trichosporonosis. Thirteen patients were diagnosed with disseminated trichosporonosis over a 20 year period in Oita Medical University Hospital. The majority of them had underlying hematologic malignancies, for which they received cytotoxic chemotherapy resulting in neutropenia. For the rapid diagnosis of this condition, we developed a novel nested-PCR assay that detected DNA specific for Trichosporon asahii and Trichosporon mucoides in the serum of patients with the condition. In a retrospective study using these serum samples, the specific DNA fragment was detected a few days to a few weeks earlier than blood culture. To treat this infection, we studied the efficacy of granulocyte colony-stimulating factor (GCS-F) alone and in combination with antifungal agents against disseminated trichosporonosis in neutropenic mice. The results suggested that GCS-F might be a useful immunomodulator against Trichosporon infections in neutropenic mice and the therapeutic outcome improved when used in combination with fluconazole. Furthermore our experimental animal model demonstrated that disseminated trichosporonosis is induced by immunosuppresion in hosts with latent trichosporonemia which was detectable by the nested PCR but not by blood culture. We found that there is a critical period for the progression of disseminated trichosporonosis after entry of fungi into the bloodstream.

Aged↗
PubMed2003

[Culture method for H. pylori].

In the five diagnostic tests for H. pylori infection recommended by the Japanese guideline, culture method may be the most difficult in clinical use, because of taking 3 to 5 days for growth, requiring a lot of skill and equipment, and having a possibility of false negative. On the other hand, it has merits of having a specificity of 100%(direct demonstration of the presence of H. pylori), allowing further investigation of the organism (determining its sensitivity to antibiotics, investigating its virulence factors, and typing it for epidemiological purposes). This method is necessary for the cases in whom strains are needed its sensitivity to antibiotics. Considering of increase of CAM-resistant H. pylori in the future, culture method should be necesary in the diagnosis of H. pylori.

Bacteriological Techniques↗
PubMed2003

[Results of survey of adult community-acquired pneumonia utilizing flow chart of diagnostic guideline for management of respiratory infections].

We performed a nationwide survey of 1,258 patients to assess the treatment of community-acquired pneumonia in Japan. Cases were classified as bacterial pneumonia in which the causal organism was unknown (Type A) or presumed (Type B), atypical pneumonia (Type C), severe pneumonia (Type D), or pneumonia in certain specific morbid states (Type E). Our objectives were to assess the actual use of antimicrobials and to determine the usefulness of the "Guidelines on Respiratory Infections--Basic Concepts in the Medical Care of Community-Acquired Pneumonia in Adults", developed by the Guideline-Drafting Committee of the Japanese Respiratory Society (JRS), in differentiating these categories of patients. We also hoped to elicit constructive opinions that would contribute to future revisions of these guidelines. The findings showed that pneumonia was classified as "bacterial pneumonia in which the causal organism was unknown" in approximately half (50.2%) of the patients studied. The next most common classification was "severe pneumonia", followed by "atypical pneumonia", "bacterial pneumonia in which the causal organism was presumed", and "pneumonia in certain specific morbid states", in that order. Our results suggest that the JSR guidelines, including the methods for differentiating between bacterial pneumonia and atypical pneumonia, are useful and appropriate, and that antimicrobial agents were generally selected in accordance with the guidelines. We also identified a number of issues to be addressed in future updates of the guidelines, including criteria for physiological assessment, handling of cases in which physical findings and laboratory test results are not in agreement, age-related issues (especially the treatment of patients 65 years of age and older), the differentiation between bacterial pneumonia and atypical pneumonia, the weighing of underlying diseases and complications, and guidelines regarding the use of adjuvant therapy.

Adolescent↗