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Biomedical subjects

T Wada

Publications and source records attributed to T Wada.

At least 775 records · Page 43Linked to original sources
PubMed1988

Digital image processing of periapical radiographs.

Periapical radiographs were processed digitally with an image-processing system. In processed images obtained with an aperture of 100 X 100 micron 2, some radiographic information was lost because the aperture was too large for processing of periapical radiographs. Greater noise and more artifacts were also present and occasionally disturbed the interpretation. Therefore, we conclude that digital image processing of periapical radiographs is not always useful. Improvement of contrast was obtained, however, and this seemed to be effective for low-contrast radiographs.

Humans↗
PubMed1988

Fate and distribution of an antitumor protein-bound polysaccharide PSK (Krestin).

The fate of 14C-labelled PSK in the body was investigated. Although only substances with low mol. wt were observed in blood shortly after the administration, with time, substances with high mol. wt appeared, suggesting absorption of PSK in its original form from the digestive tract. 14C-labelled PSK was distributed in bone marrow, salivary gland, brain liver, spleen, pancreas and tumor. Approximately 70% of 14C-labelled PSK was excreted by expiratory air after 24 h and approximately 15-20% in urine after 72 h. Only a small amount of 14C-labelled PSK was transferred into lymph and bile. The present study on the in vivo behavior of PSK provides an important basis for further analysis of its pharmacological actions.

Absorption↗
PubMed1988

A simplified tritiated thymidine incorporation assay for chemosensitivity testing of human tumors.

Chemosensitivity testing was performed using a simplified rapid assay based on tritiated thymidine incorporation. In this assay, 1.5 X 10(5) tumor cells were cultured for 72 h in double-layer agarose in 25 mm plastic dishes, which had a Millipore membrane sealed to the underside. After 24 h labeling of the cells with tritiated thymidine, cells were collected on the membrane by evacuating the solubilized medium through the filter sealed to the underside of the dish, which was placed in a boiling water bath. The radioactivity of the collected cells was counted by liquid scintillation. We found that 65% of 68 malignant tumors gave evaluable chemosensitivity results. Overall, chemotherapeutic drugs caused a 38% response rate in vitro. Twenty instances were evaluable for in vitro-in vivo correlations. The predictive accuracies were 93% for resistance and 67% for sensitivity. The results indicate that, with technical simplicity and shorter time course (4 days), this assay may be useful for chemosensitivity testing in human tumors.

Antineoplastic Agents↗
PubMed1988

Hemodynamic characteristics of the vertebrobasilar system in moyamoya disease: a histometric study.

Two autopsy cases of adult moyamoya disease were investigated by histometric and histopathologic techniques and the findings compared with those in three normotensive and five hypertensive controls in order to clarify the hemodynamic characteristics of the vertebrobasilar system in this disease. A thorough histologic examination of the vertebral and basilar arteries revealed that the fundamental arterial structures were well preserved in the vertebrobasilar system, unlike in the internal carotid system. A histometric study disclosed that the mean thickness of the media was considerably greater than that in comparable arteries of normotensive controls. From these observations, it was suggested that the essential arterial alterations in the vertebrobasilar system in moyamoya disease were hypertensive in nature and that this might be due to the increased pressure load on this system to compensate for the occlusive state of the internal carotid system. The medial hypertrophy in the vertebrobasilar system, even after massive medial atrophy in the carotid system, was impressive and suggestive of the complexity of hemodynamic changes and consequent tissue responses in this moyamoya disease.

Adult↗
PubMed1988

Radiographic characteristics of the calcifying odontogenic cyst.

4 additional cases of calcifying odontogenic cysts (COC) were reported, together with the radiographic interpretation of 138 cases from the literature. From the review of the literature and of our own cases, the root resorption is one of the most common diagnostic findings as is cystic radiolucency accompanied by radiopacities. Other radiographic characteristics, such as loculation, tooth divergency and bone resorption were emphasized.

Adolescent↗
PubMed1988

Distinct antitumor mechanisms of recombinant murine interferon-gamma against two murine tumor models.

The antitumor activity of recombinant murine interferon-gamma (rMuIFN-gamma) against B16 melanoma and EL4 thymoma, which display different sensitivities in in vitro tests, was studied. In antiproliferation tests, B16 cells were highly sensitive to rMuIFN-gamma and growth was markedly inhibited at as low as 10 U/ml, whereas EL4 cells resisted treatment even at concentration as high as 10(4) U/ml. One of these two tumors was inoculated i.d. into C57BL/6 mice and then rMuIFN-gamma (10(4) units) was repeatedly injected s.c. starting 1 day after the tumor inoculation. For the B16-bearing mice, tumor growth was markedly suppressed and the mean survival period was prolonged, but cured mice were not observed. For mice bearing EL4 cells, the therapeutic effects were more pronounced and cured mice were observed. The EL4-cured mice showed in vivo protective immunity against EL4 tumors but not against P815 tumors, indicating tumor specificity. Histologically, a large number of lymphocytes had infiltrated the necrotic tumor mass. These results indicated that rMuIFN-gamma may have not only a direct effect but also an indirect effect in host-mediated murine response on the growth of murine tumor cells under in vivo conditions.

Animals↗
PubMed1988

Regulation of in vivo immunological reactions by monoclonal antibody against lymphocyte activation antigen.

In vivo effects of a monoclonal antibody that recognizes rat lymphocyte activation antigen were studied. Spleen cells obtained from sheep red blood cell (SRBC)-immunized rats developed strong PFC response against SRBC. However, the 5C6-F4 treatment resulted in the inhibition of subsequent development of PFC response. The suppression of PFC response was due to the inhibition of generation of helper T cells, but not due to the preferential induction of suppressor cells. In addition, 5C6-F4 antibody was also found to inhibit the clinical expression of collagen-induced rat arthritis and the synovial inflammation in collagen-induced arthritis rats. Furthermore, the in vivo generation of cytotoxic cells against syngeneic tumor cells was also inhibited by 5C6-F4 antibody. The in vivo administration of 5C6-F4 antibody did not cause any pathological changes in brain, lung, liver, kidney, spleen, thymus, and lymph nodes.

Animals↗
PubMed1988

[A case report of long-term survival in advanced gastric cancer with multiple liver metastases treated with mitomycin C and tegafur therapy after palliative gastrectomy].

A 64-year-old male with advanced gastric cancer with multiple liver metastasis was treated with intensive chemotherapy including mitomycin C and tegafur after palliative gastrectomy. The patient was medicated with 30 mg iv of mitomycin C after surgery and 1,000 mg ir or 1,200 mg po of tegafur for one year for induction therapy and 400-600 mg po of tegafur for long-term maintenance therapy. All metastatic lesions in liver were completely eliminated three years after the start of treatment. As to acute and chronic toxicity, slight leukopenia was noted in the treatment, but the patient was found to show a good quality of life because of less toxicity. The patient has been healthy with no evidence of malignancy at nine years and nine months after the surgery. The total cumulative dose of tegafur in this treatment was 1,141.0 g, which is probably the largest dose ever reported in Japan, suggesting that the combination of mitomycin C and tegafur is indicated as a modality for advanced gastric cancer with liver metastasis.

Adenocarcinoma, Papillary↗
PubMed1988

[The study of intratumoral PO2 in brain tumors].

The aim of this study was to evaluate the hypoxic cells in the human brain tumor in vivo. Untreated 16 cases of brain tumor were analysed. During the surgery for the purpose of removal of the tumor, needle type-O2 sensors were inserted into femoral artery and in brain tumor to measure PaO2 and intratumoral O2 pressure. A plate type O2 sensor was put on the surface of surrounding brain cortex to measure cortical O2 pressure. These O2 sensors for this study is able to measure O2 pressure continuously and to observe these three O2 pressure simultaneously. Operations were performed endotracheal anesthesia under inhalation of ethrane with maintaining systolic blood pressure 120 mmHg. Setting the rate of O2 and N2O gas inhalation 1/3, PaO2 revealed about 110 mmHg which is similar value as physiological state--1 ATM, air inhalation--. The value of TuO2 and BrO2 were revealed 15.3 +/- 2.3 (mean +/- SE) mmHg and 59.8 +/- 6.5 (mean +/- SE) mmHg. According to these results, it might be said that hypoxic fraction surely exist intratumoral tissue. It is also well known that O2 removes from higher pressure zone to lower pressure zone after O2 was diffused from red blood cell in brain tissue. It might be also mentioned that much lower hypoxic fraction than the value of this study is existing intratumoral tissue. It has long been recognized that hypoxia influences the response of cells and tissues to radiation. However, they have been suspected on the basis of experimental data in vitro. This study showed hypoxic fraction in human brain tumor tissue in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1988

[Arterial infusion chemotherapy and embolization in unresectable hepatocellular carcinoma using an intraarterial catheter].

We performed arterial infusion chemotherapy and embolization on 22 patients with unresectable hepatocellular carcinoma via an intraarterial catheter, which was inserted in the hepatic artery under laparotomy. The administration frequency of intraarterial chemotherapy on a patient was 1 to 155 with a median of 17, while that of embolization was 1 to 6 with a median of 2.5. The maximal and average durations of a catheter in place were 15 and 4 months, respectively. The survival rates were 50% in one year, 18% in two years, and 12% in three years. Insertion technique and management of the catheter are relatively safe and easy, so catheterization of the hepatic artery would enable us to develop new treatment modalities.

Adult↗
PubMed1988

The role of the neu oncogene product in cell transformation and normal development.

p185neu, the protein product of the neu gene, is a tyrosine kinase receptor with structural similarity to the epidermal growth factor (EGF) receptor. The cognate ligand for the p185neu receptor remains unknown. We have defined: 1) stage and tissue-specific expression patterns of the neu gene product in developing tissues; 2) p185neu phosphorylation and the regulation of p185neu tyrosine kinase activity by EGF. 3) Synergistic interactions of cellular rat p185neu and EGF receptor leading to cell transformation; 4) structural and functional differences of normal and oncogenic p185neu. These observations explain some features of how p185neu is involved in normal development and neoplastic transformation.

Animals↗
PubMed1988

Feedback analysis of the behavior of the renin-angiotensin system under inhibition of angiotensin-converting enzyme.

It was previously shown that autoregressive modeling can be used for feedback analysis in the body. We used this method to investigate the dynamic changes in and around the renin-angiotensin system in vivo induced by angiotensin-converting enzyme (ACE) inhibition. Long-term studies were performed on rabbits, which were given a daily injection of one of the following ACE inhibitors: captopril, foroxymithine, or histargin. For comparison, other rabbits received injections of saline or the renin inhibitor pepstatin. Autoregressive coefficients were computed from the raw data thus observed and were used to simulate the impulse-response function proper to each animal. The response of each animal estimated in this way exposed the effects of ACE inhibitors in vivo which were obscured by the feedback regulation of the renin-angiotensin system. Also, it was suggested that histargin has a peculiar action, blocking the negative feedback that would be elicited by the usual ACE inhibition. Feedback analysis seems to be essential to elucidate the in vivo effects of enzyme inhibitors.

Angiotensin-Converting Enzyme Inhibitors↗