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Masatoshi Tanaka

Publications and source records attributed to Masatoshi Tanaka.

At least 19 recordsLinked to original sources

Surgical outcome of laparoscopic radical prostatectomy: summary of early multiinstitutional experience in Japan.

BACKGROUND: Because laparoscopic radical prostatectomy requires significant laparoscopic expertise, it needs to be evaluated critically before being accepted as a standard therapeutic option for localized prostate cancer. METHODS: A total of 148 men diagnosed as having clinically resectable prostate cancer underwent laparoscopic radical prostatectomy at seven different institutions in Japan. Early biochemical and oncological outcomes were investigated. RESULTS: Policies underlying the selection of laparoscopic radical prostatectomy did not appear to be consistent among the participating institutions. Pathologically organ-confined disease was found in 64.0% of the patients who had undergone neoadjuvant therapy and in 77.2% of those who had not. Positive surgical margins were found in 36.0% and 34.1%, respectively, of the specimens. The most common site was the apex, which accounted for 77.8% of positive margins in patients who had undergone neoadjuvant therapy and 50.0% in those who had not. Seven patients have experienced biochemical failure at a median follow-up of 9.0 months. No clinical progression has been reported. CONCLUSIONS: Continuing improvements in each step of laparoscopic radical prostatectomy, especially apical dissection, should be sought as we pursue the goal of still better oncological outcomes. A systematic approach and therapeutic guidelines should help to reduce the learning curve for competent performance of this procedure.

Aged↗

Tendency toward increase in the frequency of isolation of beta-lactamase-nonproducing Neisseria gonorrhoeae exhibiting penicillin resistance, and recent emergence of multidrug-resistant isolates in Japan.

Six hundred and ninety-nine strains of Neisseria gonorrhoeae were examined by the agar dilution method according to the M7-A5 guidelines established by the National Committee for Clinical Laboratory Standards (NCCLS) determine to their beta-lactamase production and susceptibility to penicillin G, cefixime, ceftriaxone, tetracycline, spectinomycin, ciprofloxacin, and azithromycin. The frequency of isolation of penicillinase-producing N. gonorrhoeae decreased gradually, from 7.3% of the test isolates (55 isolates) in 1995 to about 1% in 1998 and 1999. In contrast, while beta-lactamase-nonproducing N. gonorrhoeae exhibiting chromosomally mediated penicillin G resistance were not isolated from clinical specimens in 1995, the incidence of isolation of such resistant strains increased markedly, to 8.2% of 159 isolates, in 1997 and 14.9% of 242 isolates in 1999. The incidence of the isolation of tetracycline-resistant strains also increased between 1996 (none detected) and 1998-1999 (each 7%-8%), and a tendency towards an increase in the frequency of isolates of ciprofloxacin-resistant strains was also observed between 1995 (9.8%) and from 1997 to 1999 (more than 20%). There were no isolates resistant to any two antibiotics among penicillin G, tetracycline, and ciprofloxacin until 1997, but, in subsequent surveys in recent years, multidrug-resistant isolates (resistant to penicillin G, tetracycline, and ciprofloxacin) were detected in 1999.

Chromosomes, Bacterial↗

Simultaneous determination of percentage of Lens culinaris agglutinin-reactive alpha-fetoprotein and alpha-fetoprotein concentration using the LiBASys clinical auto-analyzer.

BACKGROUND: Lens culinaris agglutinin (LCA)-reactive alpha-fetoprotein (AFP-L3) percentage of total AFP concentration [(AFP-L3/total AFP)x100] has been used as an effective marker for earlier diagnosis, for assessment of therapeutic effects and for predicting the prognosis of hepatocellular carcinoma (HCC). METHODS: A new clinical automatic analyzer, the "LiBASys", and an assay kit for the simultaneous determination of AFP-L3 percentage and concentration of AFP in human serum were developed. LiBASys performed automatic re-measurement and also met stat samples. Both AFP-L3 percentage and AFP concentration were calculated simultaneously and printed out continuously every 3.4 min per test. RESULTS: A linear dose-response relationship was observed up to 1000 ng/ml AFP concentration. The detection limit and functional sensitivity of LCA-nonreactive AFP (AFP-L1) and AFP-L3 concentrations were 0.4 and 0.8 ng/ml, and 0.4 and 1.0 ng/ml, respectively. Interassay CVs of AFP-L3 percentage and AFP concentration ranged from 2.8% to 13.4% and 2.6% to 4.6%, respectively. Assay results exhibited good correlations with those of commercially available lectin-affinity electrophoresis (r=0.984) for AFP-L3 percentage and with the RIA method (r=0.999) for AFP concentration. CONCLUSIONS: This method simultaneously yields both qualitative and quantitative results for AFP-L3 percentage and AFP concentration.

Adult↗

Portal vein invasion and intrahepatic micrometastasis in small hepatocellular carcinoma by gross type.

Background/AIMS: Recurrence due to clinically undetectable intrahepatic metastasis and portal vein invasion of HCC cells is not 'uncommon' even in small HCCs. The present study investigated the relationship between these factors and macroscopic types of HCC. METHODS: Surgically resected 209 cases of small HCC less than 3 cm in diameter were examined. Macroscopically, 209 cases were divided into 'vaguely nodular type', 'single nodular type', 'single nodular type with extranodular growth' and 'confluent multinodular type'. RESULTS: None of the vaguely nodular type had intrahepatic metastasis or portal vein invasion, and their diameter was significantly smaller than the other three types. 'Single nodular type with extranodular growth' and 'confluent multinodular type' show higher frequency of portal vein invasion and intrahepatic metastases than 'single nodular type'. Among 149 metastatic lesions, the distance was 10 mm or shorter in 118 (79.2%). CONCLUSIONS: It is important to precisely determine the gross type of small HCC by diagnostic imaging in order to predict portal vein invasion and micrometastasis. It is also important to ablate the tumor with enough surrounding tissue 1 cm in width at least to prevent the recurrence from those micrometastasis.

Journal Article↗

Association of troglitazone-induced liver injury with mutation of the cytochrome P450 2C19 gene.

An anti-diabetic agent, troglitazone, was withdrawn from the market because of its association with liver injury. However, the mechanism of the injury has not been elucidated. We examined, retrospectively, the frequency of the polymorphisms of the cytochrome P450 (CYP) 2C19 and 2D6 genes in eight patients with type 2 diabetes who had troglitazone-induced liver injury and 31 subjects who tolerated troglitazone well. Polymorphisms of CYP 2C19 and 2D6 genes were analyzed by polymerase chain reaction using peripheral white blood cells. The incidence of mutations was compared with known population data for the Japanese. Homozygous or compound heterozygous mutations in CYP 2C19 alleles were found in four of the eight (50.0%) patients with troglitazone-induced liver injury. This rate was significantly higher than that in patients without liver injury (four of 31, 12.9%). The frequency of P450 2D6 mutations was the same in both groups. In conclusion, troglitazone-induced liver injury occurred more frequently in subjects with the CYP 2C19 mutations in Japanese patients.

Journal Article↗

Clinical significance of antibody against hepatitis B virus core antigen in patients with hepatitis C virus-related hepatocellular carcinoma.

PURPOSE: We investigated the unsettled issue of whether seropositivity for antibody to hepatitis B core antigen (anti-HBc) affects characteristics of hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC). METHODS: Antibody status was determined by enzyme immunoassay in 243 patients with this cancer, and associations with clinicopathologic characteristics and outcome were analysed. Serum hepatitis B virus (HBV) DNA was determined by real-time polymerase chain reaction. RESULTS: Of 235 patients with unequivocal serologic status, 142 were seropositive and 93 were seronegative. Clinicopathologic characteristics and overall cumulative survival rates were comparable between the two groups. However, seropositivity tended to predict poor outcome for patients in Child class B or C (P=0.068), those in tumour-nodes-metastasis-based stage 3 or 4 (P=0.081), those with tumours exceeding 25 mm (P=0.068), and those with a past history of clinical liver disease (P=0.088). Multivariate analysis identified serum albumin, portal vein tumour thrombosis, and tumour size as independent determinants of survival. Serum HBV DNA was below 1.7 log copies/ml in all 40 patients tested. CONCLUSIONS: Overall, the clinical features of HCV-HCC were unaffected by seropositivity for anti-HBc. Seropositivity tended to worsen prognosis for subgroup with poor hepatic reserve or advanced tumours.

Adult↗

Morbidity of laparoscopic radical prostatectomy: summary of early multi-institutional experience in Japan.

AIM: Laparoscopic radical prostatectomy is being evaluated throughout the world. The aim of the present study is to report early multi-institutional experience of the procedure in Japan. METHODS: A total of 148 men who were diagnosed with clinically localized prostate cancer underwent laparoscopic radical prostatectomy at seven different institutions in Japan. Early complications (within 30 days postoperatively) and postoperative convalescence were reviewed retrospectively. The median age of patients was 68.0 years (range, 51-80). RESULTS: The median operative time was 403 minutes (range, 167-925; average, 427). Blood loss ranged from 50 to 5000 mL (median, 540; average, 856). A total of 66 complications were reported in 55 patients (37.2%). Intraoperative complications were noted in 25 of 148 patients (16.9%): 10 rectal injuries (6.8%); five bladder injuries (3.4%); five cases of subcutaneous emphysema (3.4%); two intestinal injuries (1.4%); one major vessel injury (0.7%); one ureteral injury (0.7%); and one obturator nerve injury (0.7%). Overall, 16 of 148 patients (10.8%) required open conversion or postoperative open surgical repair. The most common postoperative complications were anastomotic leakage (6.8%), wound-related complications (4.7%) and perineal pain (4.7%). The bladder catheter was removed on day 7 or earlier in 73 cases (49.3%). The median time to ambulation was 1 day (mean 1.4, range 1-5). Oral intake was started on postoperative day 1 in 67 patients (45.2%) and on postoperative day 2 in 65 (43.9%). CONCLUSION: Although laparoscopic radical prostatectomy is technically demanding, reduced blood loss and shorter convalescence periods can be expected from the procedure. Surgeons should be aware of the disturbingly high morbidity rate related to early experience. By mastering laparoscopic skills and sharing knowledge, surgeons could reduce the impact of the learning curve required to complete this procedure competently.

Aged↗

Diagnostic clues for recurrent hepatocellular carcinoma: comparison of tumour markers and imaging studies.

OBJECTIVE: To elucidate the usefulness of monitoring Lens culinaris agglutinin-reactive alpha-fetoprotein (AFP-L3) and des-gamma-carboxy prothrombin detected with a revised kit (DCP-R) as clues to the diagnosis of recurrent hepatocellular carcinoma (HCC). METHODS: A total of 57 patients with HCC were enrolled in the study. They were classified into two groups: group A comprised 27 patients in whom the diagnostic clue to recurrent HCC appeared before November 1997; these patients were monitored by ultrasonography, computed tomography (CT), AFP and des-gamma-carboxy prothrombin detected with a conventional kit (DCP-C). Group B comprised 30 patients in whom the diagnostic clue to recurrent HCC was detected after November 1997; these patients were monitored by ultrasound, CT, AFP, AFP-L3 and DCP-R. RESULTS: In group A, 22 and five HCC recurrences were recognized initially by imaging studies and tumour markers, respectively. In group B, 17 and 13 HCC recurrences were recognized initially by imaging studies and tumour markers, respectively. The number of patients in whom tumour markers were the first clue to the diagnosis of recurrent HCC was significantly higher in group B than in group A. CONCLUSIONS: Periodic examination of AFP-L3 and DCP-R may be useful for the early detection of recurrent HCC.

Aged↗

[Bacteriological and epidemiological study on Neisseria gonorrhoeae isolated from the pharyngeal specimens of male and female patients with gonorrhea].

Neisseria gonorrhoeae were isolated from pharyngeal specimens of male and female patients and also from urethral and cervical discharges of male and female patients, respectively, suspected of having gonococcal infections in a urologic clinic in Kawasaki City. Microbiological and epidemiological studies were performed in 127 male and 41 female patients. The specimens were streaked onto the modified Thayer-Martin Selective Agar and the plates were incubated at 35 degrees C for 48 h under an atmosphere of 10% CO2. In 127 male patients, N. gonorrhoeae were detected in 117 (92.1%) of the urethral specimens. In these patients, N. gonorrhoeae were detected in pharyngeal specimens from 14 (11.0%) patients, but the pathogen was also detected in urethral specimens from these patients without exception. In 41 female patients. N. gonorrhoeae were detected in 20 (48.8%) of the 41 cervical discharges. When the pharyngeal specimens were tested, N. gonorrhoeae were detected in 14 (34.1%) of the 41 specimens. N. gonorrhoeae was simultaneously detected only in pharyngeal and cervical specimens from 11 of the 41 female patients and the pathogen was detected only in pharyngeal specimens from other 3 patients. There were no marked differences in antimicrobial susceptibilities between N. gonorrhoeae isolates from pharyngeal specimens and those from urethral or cervical discharges in all the patients tested. The PFGE patterns of 50 gonococcal isolates (25 pairs) from 25 patients (14 males and 11 females) in whom N. gonorrhoeae were simultaneously detected from pharyngeal and urethral or cervical specimens were analyzed. In 24 of 25 patients. N. gonorrhoeae isolated from the pharyngeal and urethral or cervical specimens in the same patients showed the same PFGE patterns. However, the 25 pairs showed the different PFGE patterns. From these results it is clarified that N. gonorrhoeae are detected in the pharyngeal specimens from considerable numbers of patients with gonorrhea, and there is a possibility that the pathogens prevailing among the patients differ in genetic sources.

Cervix Uteri↗

Light and electron microscopic analyses of immediate and late tissue damage caused by radiofrequency ablation in porcine liver.

Radiofrequency ablation (RFA) is an effective procedure for localized hepatocellular carcinoma. Contrast-enhanced CT depicts the ablated area as a hypoattenuated area without hepatic blood flow; however, light microscopy does not show obvious necrosis in the ablated area. We evaluated liver tissue changes after RFA by light microscopy and electron microscopy. The normal livers of three anesthetized pigs were coagulated using RFA after laparotomy. The liver was examined immediately, and 1 week after operation by light and electron microscopy. After RFA, the liver parenchyma surrounding the needle electrode was brown in color and surrounded by a red marginal zone separate from the normal liver parenchyma. Hematoxylin-eosin staining of the central area did not show cell necrosis, and the structures of liver sinusoids, liver cell cord and the nuclei of hepatocytes were preserved. However, electron microscopic examination of tissue immediately after RFA showed destruction of mitochondria of hepatocytes and fixation of sinusoidal cells. One week later, there was a large quantity of debris in the enlarged sinusoids, in addition to irreversible destruction of hepatocyte organelles. RFA of the porcine liver causes hepatocyte damage. This damage was not evident by light microscopy but clearly identified by electron microscopy.

Animals↗

[Formaldehyde exposure levels and exposure control measures during an anatomy dissecting course].

The evaporation of formaldehyde from cadavers can produce high exposures among students and instructors. A possible causal role for formaldehyde has been considered likely for tumor of the nasopharynx and the nasal cavities in human beings. Due to this reason, Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT) has set a guideline, which includes--decrease in gaseous formaldehyde in gross anatomy dissection laboratories and a guide to medical students about the toxicity of formaldehyde and protective method to avoid damages to skin, mucous, membrane, etc, in 2002. To understand what effective plans should be regarding the awareness of students about this notification, this study measured the gaseous formaldehyde concentrations in the anatomy dissection room and also analyzed the formaldehyde-related symptoms, and frequency of using protective measures. The study was conducted over a period of 3 months during the anatomy dissection exercise. We found that immediately after removing the cadavers' plastic covering, formaldehyde concentrations in the dissection room increased sharply. The concentration reached a peak point of 0.62 ppm after 10 minutes of starting of the class. This was much above the recommended level of 0.5 ppm set by Japan Society for Occupational Health. After 30 minutes of achieving the peak the formaldehyde level started decreasing gradually to a level of 0.11 ppm. Formaldehyde-related symptoms were observed in 59% of students. They had experienced symptoms of irritation of eyes, nose, throat, airways, skin, and headache during the course. Ocular discomfort was found significantly higher in the contact lenses users compared to the spectacle users or the normal eye sight group. Although, the guidelines about toxicity of formaldehyde and its protective measures to prevent damages to skin, mucous membrane etc. were informed to every student, only 52% of the students used both the mask containing activated carbon and the rubber gloves in every practical class without fail. Environmental Health Criteria 89 of International Program of Chemical Safety states, "It must be regarded that formaldehyde fluid is not absorbed directly into tissues through the skin". So the students may be allowed in some cases to touch the cadaver, treated by formaldehyde content fixative, by bare hands to understand the feel of certain organs and tissues. These results support that the rules of health supervision including necessity to use of protective measures, monitoring of indoor air formaldehyde etc. should be adhered by students and instructors in anatomy dissection room during the practical class.

Air Pollution, Indoor↗

Hepatic arterial infusion chemotherapy for advanced hepatocellular carcinoma with portal vein tumor thrombosis: analysis of 48 cases.

BACKGROUND: The prognosis of patients with hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) is extremely poor. The aim of this study was to elucidate the efficacy of hepatic arterial infusion chemotherapy (HAIC) for patients with advanced HCCs. METHODS: Forty-eight HCC patients with PVTT were treated by HAIC via a subcutaneously implanted injection port. Of these, 14 had PVTT in the second portal branch and 34 patients had PVTT in the first portal branch or in the main portal trunk. One course of chemotherapy consisted of daily cisplatin (7 mg/m(2) for 1 hour on Days 1-5) followed by 5-fluorouracil (170 mg/m(2) for 5 hours on Days 1-5). Patients were scheduled to receive four serial courses of HAIC. Responders were defined as having either a complete response (CR) or partial response (PR) and nonresponders were defined as exhibiting stable disease or progressive disease. The prognosis after HAIC and factors related to survival were analyzed. RESULTS: Following HAIC, 4 and 19 patients exhibited a CR and PR, respectively (response rate = 48%). The 1, 2, 3, and 5-year cumulative survival rates of 48 patients treated with HAIC were 45%, 31%, 25%, and 11%, respectively. Median survival periods for 23 responders and 25 nonresponders were 31.6 (range, 8.3-76.9) months and 5.4 (1.9-29.0) months, respectively. Therapeutic effect (P < 0.001) and hepatic reserve capacity (P = 0.021) were identified as significant prognostic factors by univariate analysis. Multivariate analysis identified only therapeutic effect as being significantly related to survival. CONCLUSIONS: HAIC using low-dose cisplatin and 5-fluorouracil may be a useful therapeutic option for patients with advanced HCC with PVTT. HCC patients with PVTT who respond to HAIC could certainly have survival benefits.

Aged↗

A remarkable reduction in the susceptibility of Neisseria gonorrhoeae isolates to cephems and the selection of antibiotic regimens for the single-dose treatment of gonococcal infection in Japan.

We compared the susceptibilities of 100 Neisseria gonorrhoeae isolates obtained from January to June 2000 to a variety of antimicrobial agents, including various cephems, with the susceptibilities of 55 isolates obtained from May to December 1995. In 11 of the 15 cephems tested, the MIC50 (minimum inhibitory concentration for 50% of isolates) ratios, calculated by dividing the MIC50 for isolates from 2000 by that for isolates from 1995, showed 4-fold to 16-fold differences. The MIC90 ratios of cefodizime and cefditoren showed only a 1-fold and 2-fold difference, respectively. However, the MIC90 ratios of the remaining 13 cephems showed 4-fold to 64-fold differences. We selected the most favorable antibiotic regimens for the single-dose treatment of gonorrhea in Japan according to the antigonococcal activity and pharmacokinetics, based on the criterion (therapeutic time) proposed by Moran and Levine i.e., the regimen should produce a concentration in the serum or plasma at least four times that of the MIC90 value for at least 10 h. Of the 20 single-dose regimens evaluated, only ceftriaxone 1 g intravenously and cefodizime 1 g intravenously were found to have a therapeutic time of more than 10 h for the isolates from 2000. Our results indicated that the susceptibilities of the isolates from 2000 to all the cephems tested, except for cefditoren and cefodizime, decreased remarkably in comparison with the susceptibilities of the isolates from 1995, while parenteral ceftriaxone 1 g and cefodizime 1 g appeared to be the most favorable single-dose regimens for the treatment of gonococcal infections in Japan.

Anti-Bacterial Agents↗

Alpha-fetoprotein- and des-gamma-carboxy prothrombin-producing advanced gastric cancer.

A case of alpha-fetoprotein (AFP) and des-gamma-carboxy prothrombin (DCP) producing gastric cancer with multiple liver metastasis is reported. The simultaneous presence of Borrmann I gastric cancer and IIa aggregating type gastric cancer was noted. Borrmann I gastric cancer was a poorly differentiated adenocarcinoma, while IIa aggregating type gastric cancer was a moderately differentiated adenocarcinoma. Plasma levels of AFP and DCP were 247,000 ng/ml and 320,000 mAU/ml, respectively. Immunohistochemical staining confirmed the production of these two proteins in Borrmann I gastric cancer.

Adenocarcinoma↗

Elevation of serum MAGE-4 protein levels and prediction of hepatocellular carcinogenesis in patients with liver cirrhosis.

Early detection of hepatocellular carcinoma (HCC) is clinically important because advanced HCC limits treatment modalities for the cancer. We have previously reported that serum levels of MAGE-4 protein are strongly associated with the development of HCC. The present study was designed to determine whether elevated serum MAGE-4 protein levels can predict hepatocellular carcinogenesis in patients with liver cirrhosis before clinical diagnosis. Among 62 cirrhotic patients, 28 patients were diagnosed with HCC during the follow-up period. The levels of MAGE-4 protein and alpha-fetoprotein (AFP) were significantly elevated in cirrhotic patients with HCC. Univariate and multivariate analyses suggest that elevated serum MAGE-4 protein is more significant than AFP. Importantly, retrospective analysis of prefrozen sera of cirrhotic patients revealed a transient or continuous elevation of serum MAGE-4 protein levels in 14 of 28 cirrhotic patients with HCC (50%) before clinical diagnosis. In contrast, elevated serum MAGE-4 protein levels were observed in 3 of 33 cirrhotic patients without HCC (9%), and in 2 of 34 hepatitic patients (6%). These results indicate that elevated serum MAGE-4 protein levels can be a predictive marker of hepatocellular carcinogenesis in cirrhotic patients, thereby enabling us to treat patients at an earlier stage.

Aged↗

Clinical features of hepatocellular carcinoma seronegative for both HBsAg and anti-HCV antibody but positive for anti-HBc antibody in Japan.

OBJECTIVE: We determined the prevalence of patients with hepatocellular carcinoma (HCC) who were positive for only anti-hepatitis B core (anti-HBc) antibody among 284 Japanese patients and compared their clinical features to those who were hepatitis B surface antigen positive [HBsAg(+)]. METHODS: Serum HBsAg and anti-hepatitis C virus (anti-HCV) antibody were examined for all HCC patients. Testing for anti-HBc antibody was performed in the HBsAg(-)/anti-HCV(-) patients. The clinical factors and the survival rate were compared between the HBsAg(+) patients (HCC-B) and those positive for anti-HBc alone (HCC-PB). RESULTS: There were 19 (6.7%) HBsAg(+), 236 (83.1%) anti-HCV(+), seven (2.5%) HBsAg(+)/anti-HCV(+), and 22 (7.7%) HBsAg(-)/anti-HCV(-) among the 284 patients tested. Sixteen (72.7%) of the 22 HBsAg(-)/anti-HCV(-) patients were assigned to the HCC-PB group. The prevalence of positivity for anti-HBc alone among all 284 HCC patients was 5.6%. Significant differences between the HCC-PB and HCC-B groups were that age at diagnosis was higher in the HCC-PB group (72.1 yr) than in the HCC-B group (56.2 yr) (p < 0.001), the serum alpha-fetoprotein concentrations were lower in the HCC-PB group (8.2 ng/ml) than in the HCC-B group (43 ng/ml) (p = 0.0488), and a higher familial history of liver disease was observed in the HCC-B group (p = 0.0373). However, there was no significant difference in the cumulative survival rate. CONCLUSIONS: Positivity for anti-HBc alone is not rare compared to HBsAg(+), and the clinical features of positivity for anti-HBc alone are similar to those of HBsAg(+). Some differences in the clinical features between the two groups may be explained by differences in the time of first exposure to hepatitis B virus. Therefore, the natural course of acute hepatitis B may be reconsidered.

Aged↗