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Biomedical subjects

M Takemoto

Publications and source records attributed to M Takemoto.

At least 145 records · Page 8Linked to original sources
PubMed1979

Experimental model of calcium-containing renal stone formation in a rabbit.

An experimental method of calcium-containing renal stone formation was devised using a rabbit on normal diet. The stone formation was induced unilaterally, massively, and rapidly in an extremely high incidence by temporary obstruction of the upper urinary tract, but not by permanent obstruction. The contralateral kidney was used as a control. The initial stone formation was not solid but muddy and seemed to occur through massive crystal aggregation, resulting in concretion within a few weeks. We strongly suspect that the mechanism of this stone formation is crystal aggregation induced by temporary obstruction of the kidney. This animal model should contribute to the investigation of the process of crystal aggregation which is considered to be the most important factor in idiopathic calcium stone formation in man.

Animals↗
PubMed1977

[Evaluation of the role of brain scintigraphy in pineal tumors (author's transl)].

From January, 1969 to December, 1975, 1700 patients underwent sequential brain scintigraphy with Tc-99-m-pertechnetate. All the scintigrams were obtained on a scintillation camera with high-resolution collimator in our clinic. Intracranial tumors were confirmed in 449 cases and 21 cases out of those were pineal tumors which were diagnosed by clinical symptoms, air study, angiography and Conray-or Myodil-ventriculography. In these pineal tumors, 14 (67%) out of the 21 cases had positive scan on scintigrams. All of our cases of teratoma (one case) and teratocarcinoma (two cases) showed clear abnormal uptake, though it had been reported that they do not tend to have positive results on scintigrams. We also performed scintigraphy on 11 cases out of the 21, both before and after 60Co radiation therapy. In the cases which showed either same grade or more increased abnormal uptake on scintigrams after radiation therapy, compared with that before radiation therapy, compared with that before radiation, their prognoses were poor. On the other hand, those cases which showed decreased abnormal uptake after radiation, have had a healthy daily activities. From these experiences, it may be concluded that brain scintigraphy is clinically valuable not only for making the diagnosis, but for evaluating the effect of radiation therapy and the prognosis in the cases of pineal tumor.

Adolescent↗
PubMedDate not supplied

The effect of various chemotherapeutic agents given with mild hyperthermia on different types of tumours.

It has been shown that hyperthermia can enhance the cytotoxicity of some chemotherapeutics. However, the most effective agent(s) at elevated temperatures have yet to be determined. A previous study suggests that the drug of choice at elevated temperatures may be different from that at the physiological temperature, and that the alkylating agents may be most effective at elevated temperatures. To further investigate these possibilities, the effect of chemotherapeutic agents were compared. These agents were cyclophosphamide, ifosfamide, melphalan, cis-diamminedichloroplatinum (II), 5-fluorouracil, mitomycin C and bleomycin. Three tumours (mammary carcinoma, osteosarcoma and squamous cell carcinoma) were used. They were transplanted into the feet of C3H/He mice. When tumours reached 65 mm(3), a test agent was injected intraperitoneally. Tumours were immediately heated at 41.5 degrees C for 30 min, and the tumour growth (TG) time was studied for each tumour. Using the TG times, the TG-50 (the time required for one-half of the total number of the treated tumours to reach the volume of 800 mm(3) from 65 mm(3)) was calculated. Subsequently, the tumour growth delay time (GDT) and the thermal enhancement ratio (TER) were obtained. The GDT was the difference between the TG-50 of treated tumours and that of non-treated control tumours. The TER was the ratio of the GDT of a group treated with an agent at 41.5 degrees C to that of a group treated with the agent at room temperature. Results showed that the top three effective agents tested at 41.5 degrees C were solely alkylating agents--CY, IFO and L-PAM--for each kind of tumour. A GDT of cisplatin was smaller than those of the alkylating agents. The smallest TER, 1.1, was observed for 5-fluorouracil, which was given for mammary carcinoma, and for mitomycin C, which was given for squamous cell carcinoma. It could be concluded that the alkylating agents at elevated temperatures might be the drugs of choice for many types of tumours. The possible mechanisms of thermal enhancement associated with these agents are discussed.

Animals↗
PubMedDate not supplied

Expression of Thrombomodulin in the epithelium of the urinary bladder: a possible source of urinary thrombomodulin.

Thrombomodulin (TM) is an endothelial thrombin receptor which acts as a natural anticoagulant through inactivation of the procoagulant activity of thromin. In the present study, we demonstrated that TM is expressed on the urinary bladder epithelium. The cell line BOY established from human transitional cell carcinoma of the urinary bladder also expressed the TM message (3.7kb). These cells express an 85 kDa TM protein which is identical in size to that of MEG-01, a human megakaryoblastic cell line, reported previously. We also ascertained the expression and localization of TM in the human urinary bladder by immunohistochemical staining. TM was localized in the membranes of the transitional epithelium and the cytoplasmic region of umbrella cells. The expression of TM in the transitional epithelium increased with worsening pathological status of cystitis. Based on these results, we concluded that TM is expressed in the urinary bladder. Further, soluble TM in urine may be partially derived from the urinary bladder. At present, the physiological significance of TM expression in the urinary bladder remains to be elucidated.

Animals↗