Biomedical subjects

Ken-ichi Harada

Publications and source records attributed to Ken-ichi Harada.

34 records · Page 2Linked to original sources

PubMed2005

Limited value of perineural invasion in radical prostatectomy specimens as a predictor of biochemical recurrence in Japanese men with clinically localized prostate cancer.

The objective of this study was to determine whether the presence of perineural invasion (PNI) in radical prostatectomy specimens could be a useful prognostic parameter in Japanese men with prostate cancer. Between January 1995 and September 2003, 202 Japanese men underwent radical retropubic prostatectomy for prostate cancer without any neoadjuvant therapies prior to surgery. We retrospectively analyzed the relationship between PNI in radical prostatectomy specimens and other prognostic factors, and also assessed the significance of PNI in biochemical recurrence after radical prostatectomy. The presence of PNI was significantly related to clinical stage, pathological stage, Gleason score, seminal vesicle invasion, lymph node metastasis and tumor volume, but not pretreatment serum prostate specific antigen value. During the observation period, biochemical recurrence occurred in 20 patients (3 in patients without PNI and 17 in those with PNI), and the biochemical recurrence-free survival rate in patients with PNI was significantly lower than that in patients without PNI. In addition to-PNI, pathological stage, seminal vesicle invasion, lymph node metastasis and tumor volume were significantly associated with the biochemical recurrence-free survival rate; however, among these five factors, only seminal vesicle invasion was an independent predictor of biochemical recurrence on multivariate analysis. Despite a significant association between several prognostic parameters, PNI was not an independent predictor of biochemical recurrence; therefore, it may not provide an additive effect to consider the presence of PNI in predicting the prognosis of Japanese men who underwent radical prostatectomy if there are other conventional parameters available.

Aged↗

PubMed2004

Subkilohertz linewidths measured by heterodyne-detected coherent population trapping in sodium vapor.

Subkilohertz spectroscopy by coherent population trapping (CPT) has been performed in Na atomic vapor. The system employs a frequency-swept acousto-optic modulator for bichromatic excitation as well as a heterodyne-lock-in detection technique that permits the direct measurement of the CPT dispersion curves at a good signal-to-noise ratio. A CPT linewidth of -400 Hz was measured as well as a steep refractive-index dispersion of as much as 3.3 x 10(-10) Hz(-1), corresponding to a group velocity of 1800 m/s.

Journal Article↗

PubMed2004

Comprehensive analysis system using liquid chromatography-mass spectrometry for the biosynthetic study of peptides produced by cyanobacteria.

Microcystins are hepatotoxic heptapeptides and general tumor promoters produced by several species of the genera Microcystis, Anabaena, Oscillatoria and Nostoc. They are non-ribosomally synthesized via a mixed polyketide synthase/non-ribosomal peptide synthetase system called microcystin synthetase. We have carried out the detection, isolation and structural determination of non-toxic peptides produced together with microcystins by toxic cyanobacteria, which are classified into several groups on the basis of their structures and some of these non-toxic peptides are also non-ribosomally synthesized as well as microcystins. In the present study, we tried to correlate the secondary metabolic peptides produced by the hepatotoxic cyanobacteria with the corresponding peptide synthetase genes. An analytical method using LC-electroscopy ionization MS and photodiode array detection was developed for the exhaustive screening of cyanobacterial peptides in Japanese strains and it was successfully applied to the peptide fractions extracted from these strains. The established method was advantageous over conventional ones using the usual HPLC and matrix-assisted laser desorption ionization time-of-flight MS, because more structural information could be obtained and it is easier to distinguish microcystins from other peptides using this method. Small amounts of other peptides could also be detected by this method. The established method will contribute to the investigation of the relationship between genes encoding the peptide synthetase and secondary metabolic peptides.

Chromatography, High Pressure Liquid↗

PubMed2004

Limited usefulness of the free-to-total prostate-specific antigen ratio for the diagnosis and staging of prostate cancer in Japanese men.

BACKGROUND: The objective of this study was to evaluate the clinical significance of measuring the free-to-total (f/t) prostate-specific antigen (PSA) ratio for the differentiation of prostate cancer from benign prostatic hypertrophy (BPH) and for the staging of prostate cancer in Japanese men. METHODS: Before treatment, tPSA and fPSA were measured in 147 patients with prostate cancer and in 253 with BPH, using immunofluorometric techniques. Furthermore, the f/t PSA ratio and the tPSA density of the whole prostate (PSAD) were calculated. RESULTS: The tPSA and PSAD levels in patients with prostate cancer paralleled the clinical stage, and were significantly higher than the levels in patients with BPH, while the f/t PSA ratio was not associated with clinical stage, despite the significantly lower values in prostate cancer patients than in BPH patients. Furthermore, the tPSA and PSAD values, but not the f/t PSA ratio, were significantly different between patients with pathologically extraprostatic disease and those with organ-confined disease. Calculation of the specificity of each assay within the range of 80%-95% sensitivity showed that tPSA and PSAD provided better specificities than the f/t PSA ratio. However, there was no significant difference in specificities among these three assays. In prostate cancer and BPH patients with PSA values of 4.1-10 ng/ml, the specificities of tPSA and PSAD were also superior to that of the f/t PSA ratio. CONCLUSION: These findings suggest that measurement of the f/t PSA ratio does not provide any significant additional information for the diagnosis and staging of prostate cancer in Japanese men when tPSA and PSAD values are available.

Biomarkers, Tumor↗

PubMed2004

Proteomics approach on microcystin binding proteins in mouse liver for investigation of microcystin toxicity.

Microcystins (MC) produced by freshwater cyanobacteria are potent hepatotoxins. MC inhibit protein phosphatases (PP) 1 and 2A. MC and okadaic acid (OA), which is a similar PP inhibitor whereas it has a less affinity to PP1 than PP2A, behave similarly to primary culture hepatocytes, with inducements of phosphorylations of cytoskeleton, morphological changes and apoptosis. Although the distribution of OA in mouse liver was observed immunohistochemically, no OA injury was found. The purpose of this study was therefore to determine why only MC has specific toxicities on the liver. A systematic process of MC affinity chromatography and proteomics, using two-dimensional gel electrophoresis and MALDI-TOFMS, indicated the existence of some MC-binding proteins including the complexes of PP1, PP2A, and PP4 with their own regulatory subunits in mouse liver extracts. The competitive inhibition experiments using affinity chromatography with OA showed that two of the three protein complexes strongly interacted with OA, whereas only the complex of PP1 with the inhibitory subunit NIPP1 did not strongly interacted with OA. These results suggest that the PP1 complex is not related to the common behavior of MC and OA of primary culture hepatocytes, and is related to the specific hepatotoxicities of MC.

Animals↗

PubMed2004

Isolation of Adda from microcystin-LR by microbial degradation.

The intact Adda was isolated from microcystin-LR by a microbial degradation using an isolated Sphingomonas strain, B-9. The reaction of microcystin-LR with cell extract of this strain proceeded smoothly to give the final degradation product by way of two intermediates, linearized microcystin-LR and a tetrapeptide. The purified Adda that was structurally characterized using various spectral data did not show the toxicity to mice or inhibition to protein phosphatase activity in contrast to the native toxin.

Amino Acids↗

PubMed2004

Long-term results of adjuvant hormonal therapy plus radiotherapy following radical prostatectomy for patients with pT3N0 or pT3N1 prostate cancer.

BACKGROUND: The objective of the present study was to evaluate the efficacy of adjuvant androgen suppression in conjunction with external beam irradiation after radical prostatectomy in patients with pathologically confirmed extraprostatic disease. METHODS: Between July 1988 and October 1999, 38 patients with pT3N0 or pT3N1 prostate cancer received adjuvant hormonal therapy and external beam irradiation following radical retropubic prostatectomy and pelvic lymphadenectomy. Administration of luteinizing hormone-releasing hormone analog or castration were initiated as an adjuvant androgen suppression within 4 weeks after surgery, whereas pelvic irradiation was performed at a median dose of 50 G within 3 months after surgery. The prognostic advantage of this combined adjuvant therapy was analyzed. RESULTS: During the median observation period of 92 months, biochemical recurrence occurred in four of the 38 patients and five patients died. Of these five patients, only one died of prostate cancer progression. The 10-year biochemical recurrence-free, cancer-specific and overall survival rates of the 38 patients were 86.7%, 90.9% and 78.7%, respectively. Among several factors examined, only tumor grade was significantly associated with biochemical recurrence-free survival in these patients; however, there were no factors that were independent predictors for biochemical recurrence, based on multivariate analysis. Furthermore, biochemical recurrence-free survival in the 38 patients was significantly superior to that in 54 patients with locally advanced disease who did not receive any postoperative therapies until biochemical recurrence; however, there was no significant difference in cancer-specific and overall survival between these two groups. CONCLUSION: Despite retrospective analysis with a relatively small number of patients, results of the present study suggest favorable effects of the combined adjuvant treatments with androgen ablation and pelvic irradiation on cancer control for patients with pT3N0 or pT3N1 disease. However, considering the absence of a significant difference in cancer-specific and overall survival between patients with and without adjuvant treatments, it might not be necessary to routinely perform combined hormonal and radiation therapies in an adjuvant setting for pT3N0 or pT3N1 prostate cancer.

Aged↗

PubMed2004

Increased detection of clinically significant prostate cancer by additional sampling from the anterior lateral horns of the peripheral zone in combination with the standard sextant biopsy.

BACKGROUND: The objective of the present study was to investigate whether obtaining an increased number of biopsy cores by sampling additional areas, along with the standard sextant biopsy, results in a higher rate of detection of potentially insignificant prostate cancer. METHODS: We included 130 patients who underwent radical retropubic prostatectomy at our institution between January 1999 and June 2003 after being diagnosed as having prostate cancer based on systematic prostate biopsies that included the areas examined by standard sextant biopsies and the bilateral anterior lateral horns (ALHs) of the peripheral zone (PZ). Several clinicopathological factors were analyzed, focusing on the significance of additional sampling from ALHs in relation to the incidence of potentially insignificant cancer, which was defined as organ confined disease with tumor volume less than 0.5 cc and Gleason scores <7. RESULTS: According to the location of positive biopsy results, these 130 patients were divided into three groups as follows: 61 patients (46.9%) with cancer detected from the cores taken by standard sextant biopsy only (group A), 15 (11.6%) from ALHs of the PZ only (group B), and 54 (41.5%) from both sites (group C). There were no significant differences in age, incidence of abnormal digital rectal examination, prostate volume, or biopsy Gleason score among these three groups; however, pretreatment serum PSA value in group C was significantly higher than that in groups A or B. Pathological examinations of radical prostatectomy specimens demonstrated that there were no significant differences in the incidence of lymphatic invasion, vascular invasion and perineural invasion, or Gleason score among the three groups; however, group C had a significantly larger tumor volume than groups A or B. Furthermore, insignificant tumor was detected in eight patients in group A (13.1%), two in group B (13.3%), and four in group C (7.4%). CONCLUSION: These findings suggest that the additional sampling of biopsy cores from ALHs does not appear to increase the detection of potentially insignificant cancer, and that biological tumor characteristics seem to be similar irrespective of cancer location on the needle biopsy.

Aged↗

PubMed2004

Isolation and structural characterization of siderophores, madurastatins, produced by a pathogenic Actinomadura madurae.

Madurastatins Al (1), A2 (2) and A3 (3), novel pentapeptides that were acylated with salicylic acid at the N-terminus, were isolated from the culture broth of a pathogenic Actinomadura madurae IFM 0745 strain. These structures were mainly determined by 2D NMR and MS/MS spectral techniques. The strain produced simultaneously madurastatins B1 (4) and B2 (5) consisting of Ser and salicylic acid moieties. Compounds 1 and 4 had an antibacterial activity against Micrococcus luteus, indicating that the presence of the aziridine ring is essential for such activity. Because 1 has a strong affinity with ferric ion due to the presence of two hydroxamic acids and a salicylic acid, it is considered to be a siderophore that is a low molecular weight iron chelater. The production of siderophores may be one of the characteristics of pathogenic microorganisms.

Actinobacteria↗

PubMed2004

Clinicopathological outcome of radical retropubic prostatectomy for 200 men with prostate cancer in a single institution in Japan.

The objective of this study was to retrospectively evaluate the clinicopathological outcome of radical retropubic prostatectomy (RRP) performed at a single institution in Japan. A consecutive series of 200 patients with prostate cancer who underwent RRP and pelvic lymphadenectomy between March 1985 and April 2003 were included in this study. The median age at RRP and the observation period were 69 years old and 43 months, respectively. Clinicopathological findings were reviewed to determine parameters providing predictive information about biochemical recurrence-free, cause-specific, and overall survivals. The pathological stage was pT0 in 7 patients (3.5%), pT2a in 43 (21.5%), pT2b in 58 (29.0%), pT3a in 42 (21.0%) pT3b in 36 (18.0%), and pT4 in 14 (7.0%). Lymph node metastasis was detected in 32 of 200 patients (16.0%). Forty-seven patients (23.5%) received neoadjuvant hormonal therapy, while 48 (24.0%) underwent hormonal therapy alone or hormonal therapy plus radiotherapy following RRP as an adjuvant treatment. During the observation period, 4 patients (2.0%) died of prostate cancer, 11 (5.5%) died of other diseases and biochemical recurrence occurred in 23 (11.5%), when biochemical recurrence was defined as prostate specific antigen (PSA) persistently greater than 0.4 ng/ml. Five-year biochemical recurrence-free, cause-specific, and overall survival rates were 83.6%, 97.7% and 91.4%, respectively. Furthermore, multivariate analyses showed that lymph node metastasis or clinical stage was an independent predictive factor for cause-specific or overall survival, respectively. These findings suggest that it would be possible to achieve a favorable cancer control for patients with localized prostate cancer, including locally advanced cases, by the RRP-based combination therapies.

Aged↗

PubMed2003

Dark-state imaging for two-dimensional mapping of a magnetic field.

By imaging the dark states that are due to coherent population trapping in Na atomic vapor, we have succeeded in depicting a spatially inhomogeneous magnetic field. Highly resolved dark lines represent cross sections of the surfaces of constant magnetic fields, and they agree well with the predicted hyperfine Zeeman splitting and the two-photon selection rules of the Na atom. Mapping was made two dimensionally in real time, but extension to three dimensions is straightforward. Furthermore, unlike the previous techniques based on optical pumping, this method can be used for any magnetic-field directions.

Journal Article↗

PubMed2003

Pravastatin prevents arrhythmias induced by coronary artery ischemia/reperfusion in anesthetized normocholesterolemic rats.

HMG-CoA reductase inhibitors (statins) have been shown to decrease cardiovascular mortality. Since ventricular tachyarrhythmias are closely related to cardiovascular mortality, we tested effects of the hydrophilic statin pravastatin and the lipophilic statin fluvastatin in a rat arrhythmia model of ischemia/reperfusion and simultaneously measured serum total cholesterol level. Anesthetized rats were subjected to 5-min ischemia and 10-min reperfusion after chronic administration of oral pravastatin (0.02, 0.2, or 2 mg/kg), fluvastatin (0.2, 2, or 4 mg/kg), or vehicle for 22 days, once daily. The acute effect of pravastatin (0.2 or 2 mg/kg, once orally) was also observed. Chronically administrated pravastatin significantly reduced the incidence of ischemia-induced ventricular tachycardia (VT) from 70% (control) to 9% at 2 mg/kg, and it reduced the incidence of reperfusion-induced lethal ventricular fibrillation (VF) from 90% (control) to 20% at 0.2 mg/kg. Acute pravastatin and chronically administrated fluvastatin had no significant effect on these arrhythmias. There were no significant changes in blood pressure, heart rate, QT interval, and serum cholesterol among pravastatin-, fluvastatin-, and vehicle-treated groups. Hydrophilic pravastatin prevented reperfusion-induced lethal VF in anesthetized rats by chronic administration independent of its cholesterol lowering effect. This may be a new beneficial role of pravastatin in decreasing cardiovascular mortality.

Anesthesia↗

PubMed2003

D-galactosamine induced hepatocyte apoptosis is inhibited in vivo and in cell culture by a calcium calmodulin antagonist, chlorpromazine, and a calcium channel blocker, verapamil.

Studies were conducted in C57BL/6N Crj male mice and in cultured hepatocytes to clarify the relationship between galactosamine (GaIN) induced apoptosis and [Ca2+]i kinetics. Chlorpromazine (CPZ), a Ca(2+)-calmodulin antagonist, and verapamil (VR), a Ca(2+)-channel blocker each inhibited GaIN-induced DNA fragmentation and the appearance of apoptotic bodies. The kinetics of calcium uptake were evaluated using a calcium analyzer with the acetoxymethyl ester of fura-PE3 (fura-PE3/AM, 2.5 microM) as the calcium reporter. An increase in [Ca2+]i was detected in the cultured hepatocytes within 3 hours after treatment with 20 mM GaIN; this increase was inhibited by pretreatment with either 20 microM CPZ or 30 microM VR. Ca2+ imaging by confocal laser scanning microscopy showed that increase in [Ca2+]i after treatment with GaIN was initially localized around nuclei, while [Ca2+]i signals were later diffuse and observed throughout the cytoplasm. The activities of lactate dehydrogenase (LDH) and serum glutamate-pyruvate transaminase (sGPT), used as indicators of plasma membrane damage and leakage, however, were not reduced by pretreatment with CPZ or VR. From these findings, we infer that the DNA fragmentation in GaIN-induced hepatocyte apoptosis is associated with an elevation in the perinuclear concentration of Ca2+, but GaIN-induced necrotic cell death is triggered through pathway(s) that are insensitive to blockage of Ca2+ influx and therefore appear to occur independently of elevation in [Ca2+]i. These results help to clarify the role of calcium flux in hepatocyte apoptosis and necrosis induced by exposure to hepatotoxins in vivo and in vitro.

Animals↗

PubMed2002

Comparison of protein phosphatase inhibitory activity and apparent toxicity of microcystins and related compounds.

Two metabolites of microcystin-LR glutathione conjugate and, microcystin-cysteine conjugate, as well as microcystin-RR (MCRR) are less toxic than microcystin-LR (MCLR). In the present study, we investigated why these compounds are weakly toxic in comparison with MCLR, as the reason is still unknown and no systematic study has so far been carried out for a clarification of this issue. Although they showed almost the same inhibitory activity against protein phosphatases 1 and 2A as MCLR in vitro, the apparent toxicity of these three compounds by intratracheal administration to mice decreased to about 1/12 the level of MCLR at 100microg/kg. An immunostaining study showed that these conjugates at a sublethal dose of 200microg/kg were prominently observed in the intestine and kidney, whereas effective accumulation and bleeding were not found in the liver in spite of the larger dosage. As an explanation for these results, there may be two possibilities. First, the transport system to the liver might not function well, and second, transported toxins may be effectively eliminated by an appropriate system such as the GS-X (ATP-dependent glutathione S-conjugate exported) pump. It was concluded that the inhibitory activity against protein phosphatases is not always related to the apparent LD(50) level, and that the appearance of toxicity by microcystins depends on the balance between accumulation and metabolism in the liver.

Animals↗

PubMed2002

Hepatitis B and C viruses infection, lifestyle and genetic polymorphisms as risk factors for hepatocellular carcinoma in Haimen, China.

A case-control study was carried out to investigate the impact of factors including virus infection, aflatoxin B1, microcystins, smoking/drinking and dietary habits as well as genetic polymorphisms of aldehyde dehydrogenase 2 (ALDH2) and cytochrome P4502E1 (CYP2E1), on susceptibility to hepatocellular carcinoma (HCC) in Haimen, China. A total of 248 patients with HCC and 248 sex-, age- and residence-matched population-based controls were recruited into the study. Virus infection, and ALDH2 and CYP2E1 gene polymorphisms were assessed in 134 paired cases and controls. By univariate analysis, hepatitis B virus (HBV) infection (odds ratio [OR]=9.75; 95% confidence interval [CI]=4.71-20.2), history of intravenous injection (OR=1.50; 95%CI=1.02-2.22), average income (OR=0.63; 95%CI=0.43-0.92), frequent intake of foods rich in protein, e.g., egg (OR=0.6; 95%CI=0.42-0.87), chicken (OR=0.53; 95%CI=0.35-0.79), pork (OR=0.67; 95%CI=0.46-0.98) and fresh fish (OR=0.58; 95%CI=0.39-0.87) significantly differed between cases and controls. However, peanut intake (OR=0.66; 95%CI=0.43-1.01), source of drinking water, including tap (OR=1.33; 95%CI=0.81-2.20), deep well (OR=0.94; 95%CI=0.56-1.55), shallow well (OR=0.85; 95%CI=0.55=1.30), river (OR=0.95; 95%CI=0.65-1.38), ditch (OR=1.09; 95%CI=0.76-1.55) and pond water (OR=1.0; 95%CI=0.14-7.10) were not significantly associated with risk. Univariate analysis also indicated that the 1-1 genotype of ALDH2 (OR=1.38; 95%CI=0.86-2.23) as well as the Pst1- and Rsa1-digested c1/c1 genotype of CYP2E1 (OR=1.36; 95%CI=0.81-2.28), was slightly more frequent in the case group. On multivariate analysis, HBV infection (OR=13.9; 95%CI=5.78-33.6) and history of intravenous injection (OR=2.72; 95%CI=1.24-6.00) were still associated with significantly increased risk of HCC, while frequent intake of fresh fish (OR=0.32; 95%CI=0.12-0.86) decreased this risk. These findings suggest that whereas peanut intake, water sources as well as genetic polymorphisms in ALDH2 and CYP2E1 do not significantly correlate with the risk of HCC, HBV infection is a main risk factor, and dietary items rich in protein, especially fresh fish, might protect against the risk of HCC in Haimen, China.

Adult↗

PubMedDate not supplied

Clinical symptoms in localized renal cell carcinoma reflect its invasive potential: comparative study between incidentally detected and symptomatic diseases.

The objectives of this study were to analyze the association of clinical symptoms with several parameters in patients with organ-confined renal cell carcinoma (RCC), and investigate the difference in biologic characteristics between incidentally detected and symptomatic RCCs. This study included 132 patients who were pathologically diagnosed with organ-confined RCC after radical surgery, and their clinicopathologic features were compared to those in patients with incidentally detected and symptomatic diseases. In this series, 91 patients were incidentally diagnosed with RCC, while the remaining 41 had some clinical symptoms. The cause-specific survival in patients with incidental RCC was significantly higher than that in patients with symptomatic RCC, and the presence of clinical symptoms could be an independent predictor of cause-specific survival in these patients. Immunohistochemical staining of resected specimens from these patients were then performed with Ki-67, Bcl-2, matrix metalloproteinase (MMP)-2, MMP-9, and vascular endothelial growth factor antibodies. Despite the lack of differences in Ki-67, Bcl-2, and vascular endothelial growth factor expression between these 2 groups, significantly increased expressions of MMP-2 and MMP-9 in symptomatic RCCs were observed compared with those in incidental RCCs. Moreover, the presence of clinical symptoms in organ-confined RCC was significantly correlated with immunoreactivities of MMP-2 and MMP-9. These findings suggest that clinical symptoms have a significant impact on the prognosis of patients with organ-confined RCC and that the appearance of clinical symptoms may reflect the increased invasive potentials characterized by overexpression of MMPs.

Adenocarcinoma, Clear Cell↗