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Biomedical subjects

T Kanai

Publications and source records attributed to T Kanai.

At least 199 records · Page 11Linked to original sources
PubMed1993

Dosimetry and measured differential W values of air for heavy ions.

Heavy-ion irradiation systems were designed and constructed at two cyclotron facilities in Japan for use in various fields of radiation physics and radiation biology. A 135 MeV/u carbon beam as well as 12 MeV/u carbon and helium-3 beams were first used in experiments. We have established a systematic method for heavy-ion dosimetry at both high and low incident energies involving measurements of fluences. We also obtained differential W values (w) of air for those beams by comparing the results of fluence measurement dosimetry with ionization chamber dosimetry. The differential W values of air were found to be 36.2 +/- 1.0, 34.5 +/- 1.0, and 33.7 +/- 0.9 eV for 6.7 MeV/u carbon ions, 10.3 MeV/u 3He ions, and 129.4 MeV/u carbon ions, respectively. The w value for high-energy heavy ions approaches the W value for high-energy electron or photon beams. In ionization chamber dosimetry for a heavy-ion beam, we found a track-size effect. A difference in the track sizes of heavy ions in the gas and solid phases affected the output current of the ion chamber in the case of high-energy heavy ions.

Carbon↗
PubMed1993

Postresection prognosis of patients with hepatocellular carcinoma.

BACKGROUND AND METHODS: Between July 1973 and December 1990, 137 patients with hepatocellular carcinoma underwent potentially curative resection at our institution and were discharged from the hospital. The factors that contributed to long-term survival were studied by univariate and multivariate analyses. RESULTS AND CONCLUSIONS: The 5-year actuarial survival rate was 49%. Univariate analysis showed that smaller tumor, limited resection, wide margin, absence of tumor thrombus in the portal vein or intrahepatic metastases, and absence of tumor thrombus in the hepatic vein were favorable signs for long-term survival. Multivariate analysis revealed that wide margin and absence of tumor thrombus in the hepatic vein were significant factors. Currently, 26 patients have survived more than 5 years after operation. However, 20 (76.9%) of the 26 patients have had recurrence. The 5-year disease-free survival rate of the 137 patients is 19%. Most recurrences occurred within 3 years after operation and were observed in the remnant liver. Univariate analysis of contributory factors to disease-free survival showed that wide margin, absence of tumor thrombus in the portal vein or intrahepatic metastases, and absence of tumor thrombus in the hepatic vein were favorable signs. Multivariate analysis disclosed that wide margin and absence of tumor thrombus in the hepatic vein were significant factors.

Adolescent↗
PubMed1993

[Adoptive immunotherapy in patients with multiple hepatic cancers using lymphokine activated killer cells (LAK) and interleukin-2].

Tumor infiltrating lymphocytes (TIL) and peripheral blood lymphocytes (PBL) were isolated from 5 patients with multiple hepatocellular carcinoma (HCC) and with metastatic liver tumor. Proliferation of lymphocytes was observed following addition of interleukin-2 (700 JRU/ml) into the culture media. After analysis of LAK cells by FACS, the antitumor activities were examined. Higher levels of cytotoxic activity against tumor cells (K 562 and Daudi) have continued during the culture period ranging from 2 to 5 weeks. Adoptive immunotherapy was performed using TIL-LAK and PBL-LAK via hepatic artery for three patients with HCC and one patient with metastatic tumor. The average number of administered lymphocytes was 1 x 10(9). Reduction of tumor size was observed after this therapy, which caused no severe side effects exclusive of high fever and pleural effusion. Our results indicate that the treatment using lymphokine activated killer cells and interleukin-2 may be a promising modality for patients with multiple HCC.

Carcinoma, Hepatocellular↗
PubMed1993

[Efficacy of transarterial immuno-embolization therapy (TIE) in operable patients with hepatocellular carcinoma].

The efficacy of transarterial immuno-embolization therapy (TIE) was examined in six operable patients with hepatocellular carcinoma (HCC). We administered OK-432, fibrinogen (30 mg/ml) and thrombin (1 U/ml) through a catheter which was inserted into the tumor-feeding artery. In all patients with a high level of tumor markers (AFP and PIVKA-II), the level decreased promptly to less than the pretreatment level after TIE therapy. The therapy has not caused any serious side effects. No disturbance of the coagulation-fibrinolysis system due to TIE was observed in any patient. Histological examination of resected specimens following TIE showed massive infiltration of mononuclear cells around tumor cell nests, and lytic necrosis as well as coagulation necrosis of the main tumor and the intrahepatic metastases. Our results indicate that TIE may be an effective and promising modality for HCC patients.

Aged↗
PubMed1993

Protective effect of platelet-activating factor antagonist on ischemia-induced liver injury in rats.

Platelet-activating factor (PAF), one of the chemical mediators related to inflammation reaction, is also involved in the pathologic state induced by endotoxin or ischemia. PAF antagonist has been reported to block the action of PAF and protect cells from its deleterious effects. The effects of a PAF antagonist, CV-6209, were evaluated in this study by means of a partial liver ischemia model, in which ischemia was induced by clamping only part of the liver without causing intestinal congestion. This model allowed the study of ischemic liver injury without influence from other organs. After 30, 60, and 90 minutes of ischemia, the bile flow, ATP level, and energy charge of the ischemic lobes were compared for the effects with and without CV-6209. After 60 minutes of ischemia, those that had received CV-6209 showed more bile production and higher ATP level and energy charge, with values of 0.25 +/- 0.05 ml/hr, 3.9 +/- 0.9 nmol/mg dry liver weight, and 0.61 +/- 0.02, respectively. In contrast, the values for the control group were 0.05 +/- 0.05 ml/hr, 1.7 +/- 0.8 nmol/mg dry liver weight, and 0.43 +/- 0.08, respectively. Other liver function tests (aspartate aminotransferase and lactate dehydrogenase levels) could also be improved if an appropriate dose of PAF antagonist were administered. The results imply that PAF, as has been suggested in other studies on ischemic injury, plays a role in liver ischemia and that its deleterious effects can be blocked by PAF antagonist. We conclude that the PAF antagonist offers promise in the field of liver surgery, including liver transplantation, as a means of protecting the liver from ischemic injury.

Adenosine Triphosphate↗
PubMed1992

(6R)-5,6,7,8-tetrahydro-L-biopterin modulates nitric oxide-associated soluble guanylate cyclase activity in the rat cerebellum.

(6R)-5,6,7,8-Tetrahydro-L-biopterin (R-THBP) is a cofactor not only for aromatic amino acid hydroxylases in mammalian tissues but also for nitric oxide synthase (NOS) induced by endotoxins or cytokines in some kinds of cells. Recently it has been reported that nitric oxide (NO) has biological activity in endothelium and in brain as well. NO activates soluble guanylate cyclase (sGC). Superoxide reacts with NO easily and shortens the half-life of NO actions. We found, in a study using rat cerebellar cytosol fraction, that R-THBP itself did not directly activate sGC, but activated sGC at concentrations ranging from 0.1 to 10 microM only under NO generating conditions of activated NOS and in the presence of sodium nitroprusside. In addition, R-THBP (1 microM) did not alter the NOS activity, which was determined by L-citrulline formation. These results suggest that R-THBP may regulate sGC activity associated with NO formation in the central nervous system.

Animals↗
PubMed1992

[Biliary enhanced MR imaging by Gd-DTPA].

Biliary enhanced MRI (BEMRI) by Gd-DTPA via PTCD and/or PTGBD tube for obstructive jaundice was performed in 8 patients. In all cases, biliary tract was clearly visualised as high signal intensity on T1 weighted images. On same images, primary lesion such as common bile duct cancer was also visualised as well as portal system. In addition, MR angiography (MRA) by 2D-time of flight method was performed. MRA with BEMRI shows portal encasement on the same image as biliary tract obstruction. It suggests MRA with BEMRI may replace the other modality for obstructive jaundice.

Biliary Tract↗
PubMed1992

Intraoperative irradiation in resected carcinoma of the pancreas and portal vein.

We developed a new method that provides a wide retroperitoneal irradiation field for patients with cancer of the pancreas in whom a long invaded portal vein is resected during intraoperative radiotherapy. This method involves the use of a venous bypass with a heparinized catheter that does not require systemic anticoagulation or a pump. Anastomosis is completed after intraoperative radiotherapy. Mean (+/- SD) duration of the venous bypass was 3.0 +/- 1.5 hours (range, 2.0 to 6.6 hours), during which no abnormalities of systemic blood pressure, heart rate, and electrocardiographic activity and no signs of congestion of the intestines were observed. Eleven patients were treated with this method, and no complications ascribed to intraoperative radiotherapy or venous bypass were found. We recommend this method as safe and simple for expanding the irradiation field for intraoperative radiotherapy in patients with pancreatic cancer in whom the portal vein is resected.

Adult↗
PubMed1992

Selection of therapeutic modalities for hepatocellular carcinoma in patients with multiple hepatic lesions.

In the present study, we compared the survival of patients with multi tumor hepatocellular carcinoma (HCC) following their treatment with liver resection versus TAE. A total of 336 HCC patients were treated at Osaka University Hospital between 1980 and 1989. Of these, 140 patients underwent liver resection in the presence or absence of TAE and 173 subjects were treated with TAE alone. Our TAE protocol consisted of 50 mg Adriamycin, 3-5 ml lipiodol, and Gelfoam. The 1-, 3-, and 5-year survival values found for the liver resection group were 87.4%, 66.0%, and 47.4%, respectively, whereas the values calculated for the TAE group were 64.6%, 29.9%, and 15.8%, respectively. The survival of patients in the resection group was clearly better than that of subjects in the TAE group. Of the 140 patients who underwent resection, 36 cases were proven to have multiple lesions by histopathological examination. The 1- and 3-year survival values determined for this special group were 67.9% and 33.3%, respectively. Of the TAE cases, 113 were diagnosed as having multiple lesions by imaging examination, and their 1- and 3-year survival values were 59.7% and 24.9%, respectively. No significant differences in survival was found between these two different treatment modalities for these multiple-lesion cases. The results of this study indicate that it is unlikely that surgical resection is superior to TAE alone for the treatment of HCC patients with multiple lesions.

Adult↗
PubMed1992

Relationship between pathologic prognostic factors and abnormal levels of des-gamma-carboxy prothrombin and alpha-fetoprotein in hepatocellular carcinoma.

The relationship between pathologic prognostic factors and abnormal levels of des-gamma-carboxy prothrombin and alpha-fetoprotein was investigated in 42 patients with resectable hepatocellular carcinoma. The frequencies of macroscopic massive type, intrahepatic metastasis, and portal vein tumor thrombus were significantly higher in patients with positive des-gamma-carboxy prothrombin (p less than 0.05) but not with alpha-fetoprotein. Other histologic factors in tumorous and nontumorous tissues were not significantly different irrespective of the positivity of these markers. In patients with tumors not more than 6 cm in diameter, the frequency of intrahepatic metastasis was positively correlated with the positivity of des-gamma-carboxy prothrombin (p less than 0.05) and inversely with that of alpha-fetoprotein (p less than 0.05). Furthermore, intrahepatic metastasis was most frequently observed in patients with positive des-gamma-carboxy prothrombin and negative alpha-fetoprotein (eight of nine) and least frequently in cases with negative des-gamma-carboxy prothrombin and positive alpha-fetoprotein (one of eight). These findings indicated that both des-gamma-carboxy prothrombin and alpha-fetoprotein might be useful markers for the prediction of intrahepatic spread of hepatocellular carcinoma.

Biomarkers↗
PubMed1992

A unique case of cutaneous calcinosis with transepidermal elimination.

A case of cutaneous calcinosis with unique clinical and histological features which occurred on the cheek of a 14-year-old girl, is reported. Our case had no abnormal findings in laboratory data. Serum calcium and phosphate were normal, there was no underlying disease, and the possibility of self-inflicted dermatoses was denied. Transmission electron microscopy and X-ray microanalysis showed calcium and phosphate deposited around collagen fibers, which were eliminated from the epidermis.

Adolescent↗
PubMed1992

Reversal of alpha-methyltyrosine-induced hypoactivity by 6-(R)-5,6,7,8-tetrahydro-L-erythrobiopterin (R-THBP) in mice.

The effects of peripheral administration of 6-(R)-5,6,7,8-tetrahydro-L-erythrobiopterin dihydrochloride (R-THBP), a natural cofactor for tyrosine and tryptophan hydroxylases, were investigated in mice treated with a competitive inhibitor of tyrosine hydroxylase, alpha-methyltyrosine (alpha-MT). A subcutaneous dose of 250 mg/kg of alpha-MT decreased markedly both ambulatory activity and cerebral contents of norepinephrine, dopamine and their metabolites in mice. An intraperitoneal dose of 100 mg/kg of R-THBP, which did not alter ambulatory activities in normal mice, improved the hypoactivity in alpha-MT-treated mice. Moreover, R-THBP at intraperitoneal doses of 60 and 100 mg/kg inhibited the impairment of cerebral catecholamine metabolism induced by alpha-MT in mice. We suggest that the reversal of the alpha-MT effects by R-THBP might be due to reactivation of tyrosine hydroxylase in the central nervous system.

Animals↗
PubMed1992

Effects of nitric oxide-related compounds and carperitide on hemodynamics and hematocrit in anesthetized rats.

Sodium nitroprusside, nitroglycerin and carperitide (alpha-human ANP) all reduced mean blood pressure, but only carperitide increased the hematocrit in rats with bilateral renal artery- and ureter-ligation. NG-Monomethyl-L-arginine, a selective inhibitor of nitric oxide synthesis, elevated the mean blood pressure but did not change the hematocrit significantly. These findings suggest that ANP has a physiological role in regulating circulatory blood volume distinct from that of NO, although both increase intracellular cyclic GMP in the vasculature.

Anesthesia↗
PubMed1992

[Study of tinnitus masking by self-recording audiometer].

The tinnitus masking test, in which the minimum masking levels of tinnitus by various pure tones and band noises are measured and used to produce tinnitus masking curves, is one of the methods for evaluating the character of tinnitus. At present, the tinnitus masking test is usually performed using a pure tone audiometer. In this study, tinnitus masking curves were produced using a self-recording audiometer (Bekesy audiometer) in 22 cases of tinnitus, and the basic nature of the tinnitus masking curves from the self-recording audiometer was investigated and compared with those from a pure tone audiometer. The results showed no changes in the masking level, and the amplitudes of the tinnitus masking curves from the self-recording audiometer were observed to be at the tinnitus pitches. The amplitude of the tinnitus masking curve showed a negative correlation with tinnitus loudness as measured by the loudness balance test for tinnitus, that is, the amplitude tended to decrease as the tinnitus became louder. This suggests that the loudness of the masking tone influences the tinnitus masking phenomenon.

Audiometry, Pure-Tone↗