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Biomedical subjects

S Sawada

Publications and source records attributed to S Sawada.

At least 433 records · Page 24Linked to original sources
PubMed1987

Antitumor activity of a new camptothecin derivative, SN-22, against various murine tumors.

The antitumor activity of a new camptothecin derivative, SN-22, was evaluated by using various murine tumors. SN-22 showed strong activity against the ascites tumors Ehrlich carcinoma, MM46, CCM, L1210, L5178Y, P388, Meth A, and B16 melanoma. In particular, the maximum increase in life span values for Ehrlich, MM46 and CCM were as high as 253-606% and many mice were cured of these tumors. The effect of SN-22 against solid tumors was also determined. The inhibition ratios were higher than 70% for MM46 and L5178Y. The LD50 of SN-22 in ICR mice was about 1.5 times that of the parent camptothecin.

Animals↗
PubMed1987

Stereochemistry and mechanism of reactions catalyzed by tyrosine phenol-lyase from Escherichia intermedia.

Stereochemical studies on tyrosine phenol-lyase from Escherichia intermedia have shown that the alpha, beta-elimination reactions of L-serine and D- and L-tyrosine proceed with retention of configuration at C-beta. Stereospecifically beta-tritiated L-serine is slowly racemized at C-beta. Deuterium from the alpha-position of L-tyrosine is partially transferred to C-4 of the phenol formed when the alpha, beta-elimination reaction is carried out in H2O, although no transfer of alpha-1H in 2H2O was seen. The result favors tautomerization of the p-hydroxyphenyl to a cyclohexadienonyl moiety prior to carbon-carbon bond cleavage. In the conversion of L- to D-alanine catalyzed by tyrosine phenol-lyase, some alpha-hydrogen recycling is observed, pointing to a single-base racemization mechanism. Attempts to demonstrate cofactor motion during racemization by NaBH4 reduction of [3H]PLP-enzyme: D- and L-alanine complexes failed, but showed that, as in other PLP enzymes, the holoenzyme is reduced preferentially from the Re face with respect to C-4' of PLP and enzyme-substrate complexes preferentially from the Si face.

Carbon Radioisotopes↗
PubMed1987

Regulation of prostacyclin generation by angiotensin converting enzyme related substances in cultured human vascular endothelial cells.

The regulation of prostacyclin (PGI2) generation by angiotensin I-converting enzyme (ACE) related substances was investigated using cultured human vascular endothelial cells. Angiotensin I (AI) or bradykinin (BK) increased PGI2 generation and ACE activity, while the ACE inhibitor, captopril decreased both of them, and angiotensin II (AII) did not show any effect. The increasing rate of PGI2 generation induced by AI or BK was not affected by the pretreatment with captopril. These results suggest that the accumulation of AI or BK via the inhibition of ACE by captopril did not cause the enhancement of PGI2 generation. Rather, it was proposed that the enhanced PGI2 generation by AI or BK might be regulated by ACE activation derived from these substances, as an autoregulation mechanism.

Angiotensin I↗
PubMed1987

[Oily chemoembolization of hepatoma].

Since 1983 we have performed transcatheter oily chemoembolization (TOCE) using adriamycin (40-100 mg), Lipiodol (5-20 ml) and Gelfoam in the treatment of 100 cases with unresectable hepatocellular carcinoma. Adriamycin was dissolved in a fluid equal in specific gravity to Lipiodol and the adriamycin solution was mixed with 3 volumes of Lipiodol, making an adriamycin-in-oil emulsion (AOE). After TOCE, the blood concentration of adriamycin was obviously lower than that after one-shot injection because of the slow release of adriamycin from the AOE. Also, in cases of hepatic resection after TOCE, there was a clear difference in the adriamycin concentration between the tumor and the normal hepatic tissue. The cumulative survival rates for the 100 patients treated by TOCE were: 6 months 81.9%, 1 year 53.8% and 2 years 36.5%. Thus, improvement was found in comparison with the cumulative survival rates for 104 patients who underwent hepatic embolization without Lipiodol, which were 6 months 67.4%, 1 year 45.2% and 2 years 16.3%. AOE retained in the tumor as microemboli brings about the slow-releasing effect of adriamycin. Furthermore, by adding the effect of Gelfoam embolization, TOCE has a strong antitumor effect.

Carcinoma, Hepatocellular↗
PubMed1987

[Enhancement of anti-tumor effects by arterial embolization combined with hyperthermia in the treatment of hepatic tumors].

The effectiveness of arterial embolization using DSM (Degradable Starch Microspheres, Spherex, Sweden) combined with hyperthermia were investigated in the treatment of VX2 carcinoma in rabbits and also in human hepatic tumors. These microspheres temporarily obstructed the blood flow at the precapillary level. The blood flow in the tumor was inhibited to a greater extent and for a longer period than in normal muscle. The rise in temperature at the tumor site during heating was shown to be significantly higher than in muscle. The pH in the tumor clearly showed a stronger degree of inhibition than that achieved with hyperthermia alone. Histological examination demonstrated no marked damage to the muscle following DSM + hyperthermia. In the patients with hepatic tumor, hyperthermia was performed using an RF Thermotron 8 (8 MHz) externally, followed by injection of 15 ml of DSM combined with anti-cancer drugs via a catheter. The rise of temperature in DSM + chemo-hyperthermia during heating showed a higher value than that with hyperthermia alone and effective cases (PR) totalled 5 from among 8 cases treated. It was concluded that the heating efficiency may be improved by arterial chemo-embolization in the treatment of hepatic tumors.

Animals↗
PubMed1987

Aberration of monokine production and monocyte subset in patients with systemic lupus erythematosus.

We measured the production of interleukin 1 (IL-1) and prostaglandin by adherent cells from patients with systemic lupus erythematosus (SLE). Compared to normal subjects, IL-1 production in the patients was lower but prostaglandin E1 production was higher. Furthermore, examination of monocyte subsets in patients with SLE using monoclonal anti-monocyte/granulocyte antibodies disclosed abnormal expression of membrane antigens on monocytes. It is speculated that aberration of monocyte function is related to impaired monokine production and that membrane antigens play a role in immunodysregulation in patients with SLE.

Humans↗