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Biomedical subjects

R Yamada

Publications and source records attributed to R Yamada.

At least 523 records · Page 29Linked to original sources
PubMedDate not supplied

Prognostic relevance of urokinase type plasminogen activator, its receptor and inhibitors in chondrosarcoma.

The plasminogen activation system plays an important role in enhancing pericellular proteolysis of tumor invasion/metastasis and in autocrine/paracrine tumor growth stimulation. To investigate the prognostic significance of the plasminogen activation system in human chondrosarcoma, the immunohistochemical expression of urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), plasminogen activator inhibitor, 1 (PAI-1) and 2 (PAI-2) were analyzed in 28 patients with chondrosarcoma. In multivariate survival analysis, histological grade (p = 0.0008) and location (p = 0.02) were independent risk factors for local relapse. For metastasis-free survival, uPA index (p = 0.006) and PAI-2 index (p = 0.04) were independent prognostic factors. PAI-2 index (p = 0.02), uPAR index (p = 0.02) and histological grade (p = 0.03) predicted total survival. These results demonstrated the usefulness of uPA, uPAR and PAI-2 expression as biological prognostic indicator and the importance of the plasminogen activation system in tumor progression and metastasis in chondrosarcoma.

Adolescent↗
PubMedDate not supplied

The hemodynamics of dysplastic nodules in the liver evaluated by CT angiography and immunohistochemistry.

BACKGROUND/AIMS: Dysplastic nodules diagnosed pathologically exhibit various hemodynamic patterns. To evaluate these differences in their hemodynamics, we observed basement membrane formation of sinusoids. METHODOLOGY: For 12 low-grade dysplastic nodules, 24 high-grade dysplastic nodules and 16 hepatocellular carcinomas, both computed tomography during arterial portography and CT arteriography were performed preoperatively. Resected specimens were examined immunohistochemically for COL IV (type IV collagen) and laminin to observe basement membrane formation. We compared their hemodynamics on computed tomography during arterial portography and CT arteriography with the expressions of COL IV and laminin. RESULTS: All of the low-grade dysplastic nodules were not hypervascular on CT arteriography, and negative for COL IV and laminin. All of the hepatocellular carcinomas were hypervascular on CT arteriography, and positive for COL IV and laminin. High-grade dysplastic nodules exhibit four hemodynamic patterns on CT during Arterial Portography/CT arteriography. All of 7 iso/iso and 5 iso/hypo nodules were negative for COL IV and laminin. Of the 9 hypo/hyper nodules, which exhibited hemodynamics similar to hepatocellular carcinoma, COL IV was identified in 7 and laminin identified in 8 nodules. Of the 3 hypo/hypo nodules, COL IV and laminin were identified in one. CONCLUSIONS: In high-grade dysplastic nodules, most cases exhibited a correlation between the hemodynamic patterns and the degree of the sinusoidal basement formation.

Aged↗
PubMedDate not supplied

The role of diffusion-weighted imaging in patients with brain tumors.

BACKGROUND AND PURPOSE: Diffusion-weighted images (DWIs) have been used to study various diseases, particularly since echo-planar techniques shorten examination time. Our hypothesis was that DWIs and tumor apparent diffusion coefficients (ADCs) could provide additional useful information in the diagnosis of patients with brain tumors. METHODS: Using a 1.5-T MR unit, we examined 56 patients with histologically verified or clinically diagnosed brain tumors (17 gliomas, 21 metastatic tumors, and 18 meningiomas). We determined ADC values and signal intensities on DWIs both in the solid portion of the tumor and in the peritumoral, hyperintense areas on T2-weighted images. We also evaluated the correlation between ADC values and tumor cellularity in both gliomas and meningiomas. RESULTS: The ADCs of low-grade (grade II) astrocytomas were significantly higher (P =.0004) than those of other tumors. Among astrocytic tumors, ADCs were higher in grade II astrocytomas (1.14 +/- 0.18) than in glioblastomas (0.82 +/- 0.13). ADCs and DWIs were not useful in determining the presence of peritumoral neoplastic cell infiltration. The ADC values correlated with tumor cellularity for both astrocytic tumors (r = -.77) and meningiomas (r = -.67). CONCLUSION: The ADC may predict the degree of malignancy of astrocytic tumors, although there is some overlap between ADCs of grade II astrocytomas and glioblastomas.

Adult↗
PubMedDate not supplied

Transjugular intrahepatic portosystemic shunt in combination with oral anticoagulant for Budd-Chiari syndrome.

The antiphospholipid antibody syndrome is characterized by arterial and venous thrombosis including hepatic veins. Although transjugular intrahepatic portosystemic shunt or liver transplantation have been considered for Budd-Chiari syndrome, treatment options for patients with complete obstruction of three hepatic veins including the junction with the inferior vena cava are limited. We describe a 27-year-old female, who suffered thrombotic obliteration of hepatic veins including the portion confluent with the inferior vena cava (Budd-Chiari syndrome) associated with marked ascites and liver dysfunction. Transjugular intrahepatic portosystemic shunt using a Wall-stent (10 mm in diameter) between inferior vena cava and intrahepatic portal vein was performed. Intrastent coagulation and recurrence of thrombosis were prevented by combination therapy with warfarin potassium and ticlopidine hydrochloride. These treatments induced loss of ascites and improvement of liver function, and she has been able to resume daily life. The portosystemic shunt described above in addition to combination therapy with warfarin potassium and ticlopidine hydrochloride appeared to be one of the options for treating Budd-Chiari syndrome associated with antiphospholipid antibody syndrome.

Adult↗
PubMedDate not supplied

Expression of peroxisome proliferator-activated receptor (PPAR)-gamma in human lung cancer.

The peroxisome proliferator-activated receptor (PPAR)-gamma is a member of the steroid nuclear receptors. Recent studies have demonstrated that PPAR-gamma is expressed in several cancer cells. We examined the PPAR-gamma expression in both normal lung and major types of human lung cancer. The expression of PPAR-gamma mRNA was detected in 2 out of 3 normal lung tissues and its protein was detected in 3 out of 5 normal lung tissues. In contrast, a small cell carcinoma cell line and all other types of lung cancer tissues expressed PPAR-gamma mRNA and its protein. Immunoreactive PPAR-gamma is strongly expressed in cancer cells and moderately in mononuclear cells, endothelial cells and fibroblasts of lung cancer tissues. Our results suggest that PPAR-gamma may play an important role in the pathogenesis and/or progression of lung cancer, and may be a novel therapeutical target for therapy of lung cancer.

Aged↗
PubMedDate not supplied

Development of a new heating needle for interstitial hyperthermia compatible with interstitial radiotherapy.

PURPOSE: We have developed a new heating needle for interstitial hyperthermia compatible with brachytherapy. We studied the heating characteristics of interstitial needles and the usefulness of these needles for interstitial hyperthermia. MATERIALS AND METHODS: As heating needles, we used MicroSelectron HDR interstitial needles. These needles were only heated at the metal tip, and were insulated in the middle and grounded from the top. The hyperthermia system was based on the principles of RF capacitive heating, and we used a Thermotron RF-8. We examined whether the temperature and the heating area could be elevated to a level required for hyperthermia. RESULT: Good heating was obtained around the metal tip of the needle. The heating area of the longitudinal axis of the needle varied with the length of the metal part, while the transverse heating area of the needle was almost unchanged. If heating was performed while maintaining the elevation of temperature in each needle at the same level using variable coils (tuning box), heating was homogeneous over the regions in accordance with the arrangement of the needles. CONCLUSION: With this heating system, the temperature rises easily, and a uniform temperature distribution can be obtained.

Brachytherapy↗
PubMedDate not supplied

In vitro chemosensitivity of human soft tissue sarcoma.

Chemotherapy is essential in the treatment of small round cell sarcomas. However, as yet there is no progress concerning the efficacy of chemotherapy in the treatment of other types of soft tissue tumors (STS). The Histoculture Drug Response Assay (HDRA) is an in vitro chemosensitivity test that has a high correlation with clinical response, the usefulness of which has been reported in various kinds of solid tumors. However, there has never been a report on its use in STS until now. In this study, in order to investigate the variation in chemosensitivity in STS, fresh biopsy or surgical samples of STS were tested using the HDRA method. Drug sensitivity testing by HDRA showed that two drugs, ADM and THP, had a significantly higher inhibitory rate than CDDP, IFOS, or VP-16 in the thirty-three soft tissue sarcomas tested. Depending on the morphological type, spindle cell sarcomas were sensitive to THP, which showed significantly higher inhibition rates than CDDP, IFOS, or VP-16. Small round cell sarcomas were relatively sensitive to all of the drugs tested. However the drug sensitivity of pleomorphic cell sarcoma was low except for ADM and THP, while its sensitivity to THP was higher than about 70%. However, there are numerous other soft tissue sarcomas that do not belong to these categories; drug sensitivity testing in each of them and the devising of individualized treatment strategies seems necessary to improve the therapeutic outcome.

Doxorubicin↗
PubMedDate not supplied

Time courses of PIVKA-II and AFP levels after hepatic artery embolization and hepatic artery infusion against hepatocellular carcinoma: relation between the time course and tumor necrosis.

We examined 35 untreated patients with unresectable hepatocellular carcinoma who exhibited positivity for both plasma PIVKA-II and serum AFP, and studied the weekly course of these markers from the pre-TAE or -HAI period to the third week of treatment. We correlated changes in these markers with the tumor necrosis rate and the time course on X-ray CT images. One week after TAE, the tumor necrosis rate and the time course of PIVKA-II showed a significant correlation (r = 0.7), while the correlation was between the time course of AFP and the tumor necrosis rate was insignificant (r = 0.2). At two and three weeks after TAE, both the time course of AFP and PIVKA-II showed significant correlations with the tumor necrosis rate. In 16 patients with tumor necrosis rates of not less than 90%, the mean of the actual half-life (AHL) of PIVKA-II was 3.2 days, the shortest was 1.83 days, and 75% of all AHLs clustered from two days to four days, while the mean and shortest AHLs of AFP were six days and 2.98 days, respectively, exhibiting a broader distribution. On the other hand, in three out of the nine cases of hepatocellular carcinoma complicated with portal tumor thrombi, PIVKA-II increased after HAI in spite of a reduction in tumor size. It was suggested that the PIVKA-II level requires careful interpretation in cases of portal vein obstruction after intensive hepatic arterial infusion of anticancer agents.

Aged↗
PubMedDate not supplied

Restored activation of primary motor area from motor reorganization and improved motor function after brain tumor resection.

BACKGROUND AND PURPOSE: Reorganization of brain function may result in preservation of motor function in patients with brain tumors. The goal of the present study was to investigate whether function of the primary motor area (M1) was restored and whether motor function improved after brain tumor resection. METHODS: Five patients with metastatic brain tumors located within or near M1 underwent awake surgery with intraoperative cortical mapping and continuous task monitoring. Preoperative and postoperative functional MR imaging (fMRI) was performed during hand clenching, and diffusion tensor imaging (DTI) was performed in 1 case to further characterize the area activated in fMRI. RESULTS: Preoperative fMRI performed during hand clenching demonstrated reorganization of motor function. In patients with severe paresis (cases 3, 4, and 5), clenching of the affected hand induced a large blood oxygen level-dependent response in the right hemisphere, mainly in the anterior temporal lobe, despite the location site of the tumor. Postoperative fMRI during hand clenching demonstrated activation of the contralateral M1. Furthermore, in case 5, DTI detected tracts, possibly the inferior longitudinal fasciculus, arising from anterior temporal activated area as well as tracts connecting the premotor and M1 activated area. This patient demonstrated mirror movement of the hand during the course of motor function recovery. CONCLUSIONS: Tumor resection resulted in restoration of M1 function and improved motor function in patients with preoperative reorganization of M1 function. Furthermore, the preoperative reorganization of motor function in cases with severe paresis may be related to changes in the right hemisphere, including the temporal lobe.

Aged↗
PubMedDate not supplied

Short-term intrathrombotic injection of ultrahigh-dose urokinase for treatment of iliac and femoropopliteal artery occlusions.

Thirty-two patients with iliac and femoropopliteal artery occlusions were treated with direct intrathrombotic injection of ultrahigh-dose urokinase (10,000 IU/min). Occlusions ranged from 3 to 25 cm (average 13.3 cm) in length and the total urokinase dose from 120,000 to 1,410,000 IU (average 688,000 IU). The procedure was usually followed by balloon angioplasty to dilate the underlying stenoses. The initial recanalization rate was 96.9%, the two week patency rate 81.3%, and the cumulative one-year patency rate 66.3%. Complications associated with this procedure included three episodes of minimal bleeding, two distal embolisms, one local hematoma, and one low-grade fever. All were well controlled by palliative treatment. Results indicate that this procedure can provide rapid recanalization at a higher success rate and with fewer complications than previously reported.

Adult↗
PubMedDate not supplied

Melanin-producing medullary thyroid carcinoma with glandular differentiation.

A rare case is reported of melanin-producing medullary thyroid carcinoma in a 62-year-old man. Intraoperative imprints of the thyroid tumor revealed numerous detached tumor cells containing large amounts of brown pigment. The Fontana-Masson argentaffin reaction with bleach confirmed that those granules were melanin. Histologically, the tumor was composed of two different components--a medullary area with hyalinized stroma and a follicular area. Melanin was scattered in both areas. The tumor cells in both areas were immunoreactive to carcinoembryonic antigen, calcitonin, gastrin-releasing peptide, somatostatin, met.-enkephalin, neuron-specific enolase, chromogranin and neurofilaments, and negative for thyroglobulin and S-100 protein. The histologic diagnosis was melanin-producing medullary thyroid carcinoma with glandular differentiation. Although various kinds of peptides and amines have been reported to be produced in medullary thyroid carcinoma, melanin production is quite rare; this appears to be only the third reported case.

Carcinoma↗
PubMedDate not supplied

An attempt of hyperthermia with balloon catheter and immunochemotherapeutic agent.

The following studies were performed to develop a new technique of hyperthermia by vascular catheterization for the treatment of malignant neoplasm. A balloon catheter was inserted into the artery of a cancer-affected organ and inflation of the balloon temporarily occluded the artery, after which an anticancer drug solution warmed to 45 degrees C was infused. The purpose of this technique was to enable the solution to arrive at the affected area undiluted by blood. It would then remain in the organ and act on the lesion. When OK-432 was intravenously administered to induce pyrexia of 40 degrees C, followed by the above-mentioned arterial infusion, it was expected that the effects of hyperthermia and chemotherapy would be synergistic. In cases of liver cancer and urinary bladder cancer subjected to the arterial infusion of warmed anticancer drugs, however, the temperature in the hepatic vein increased by only 0.5 degree C while that in urethra near the tumor increased by only 1 degree C. In the future, further improvement needs to be made to obtain effective local heating with this technique.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Maternal blood total oxypurines and erythrocyte 2,3-diphosphoglycerate levels during normal pregnancy.

The effects of pregnancy on the levels of maternal plasma total oxypurines (hypoxanthine, xanthine and uric acid) and erythrocyte 2,3-diphosphoglycerate (2,3-DPG) was investigated. With advancing gestation there was a slight increasing tendency in plasma total oxypurines as well as erythrocyte 2,3-DPG in pregnant women. When the ratio of 2,3-DPG to total oxypurines was calculated, the ratio was almost unchanged until week 34. After week 35, the ratio decreased to week 37; the ratios between week 37 and 40 had similar values to cord blood. The above data suggest that the changes of these metabolites in maternal peripheral blood may be indicative for hypoxia with fetoplacental tissue.

2,3-Diphosphoglycerate↗
PubMedDate not supplied

Clear cell sarcoma of the kidney in an adult.

A 25-year-old woman with clear cell sarcoma of the kidney (CCSK) underwent computed tomography (CT), angiography, and a surgical operation. The clear cell sarcoma showed a cystic lesion with solid components on CT and a hypovascular tumor and rat-tail occlusion of the left renal artery on angiography. These findings in our adult case of CCSK corresponded with those of CCSK in childhood.

Adult↗
PubMedDate not supplied

Transvaginal fallopian tube catheterization--diagnostic and therapeutic usefulness.

Fifty-two patients with 84 proximal Fallopian tube obstructions underwent Fallopian tube recanalization (FTR). The successful catheterization rate for Fallopian tubal ostia was 100%, and the successful recanalization rate was 64%. After FTR, hysterosalpingography or selective tubography showed no evidence of adhesion (without adhesion) in 31 tubes, perifimbrial adhesion in 17 tubes, hydrosalpinx in six tubes, and intratubal adhesion in 30 tubes (unsuccessful recanalization). Six patients (11%) achieved intrauterine pregnancies and two had extrauterine pregnancies. Follow-up studies in seven patients without adhesion showed patency in one patient and reocclusion in six patients who obtained repatency after a second FTR. Fallopian tube catheterization was useful for the exact diagnosis of Fallopian tube occlusion. The higher incidence of adhesion in patients' background caused the low incidence of pregnancy.

Adult↗
PubMedDate not supplied

Lead contact lens for crystalline lens shielding in electron therapy for eyelid tumors.

In radiotherapy for eyelid tumors, a sufficient dose is required in the target tissue while preserving the crystalline lens. A I-mm thick, 20-mm diameter lead contact lens was prepared for crystalline lens protection. The lens was coated with an acrylic polymer and weighted 5.5 g. Six MeV electron therapy was scheduled using a 10 mm bolus on the eyelid. A simulation experiment proved that 0.78 +/- 0.04 percent of the maximal eyelid dose was given at the crystalline lens portion. A total of 14 eyelids in eight patients with cutaneous lymphoma, angiosarcoma, or basal cell carcinoma were treated with the contact lens. No cataract was found after irradiation over an average period of 24.3 months. The combination of the lead contact lens, bolus, and 6 MeV electron beam was a simple procedure and provided adequate dose distribution in the treatment of various eyelid tumors.

Aged↗
PubMedDate not supplied

Pitfall of superselective catheterization by 3F catheter for spinal arteriovenous malformation.

We experienced a case of subarachnoid rupture of a spinal arteriovenous malformation (AVM) following the injection of contrast medium through a 3F wedged catheter inserted into the feeding artery. If blood does not come through the catheter in the feeding artery of a spinal AVM, not even test injection should be done, to avoid rupture of the spinal AVM.

Angiography, Digital Subtraction↗