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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 739 records · Page 41Linked to original sources
PubMed1988

Metabolism of drugs in the eye. Drug-reducing activity of preparations from bovine ciliary body.

Drug-metabolizing activities, especially the reductase activities towards N-oxide, hydroxamic acid, sulfoxide and nitro compounds were comparatively examined with bovine ciliary body. As described previously, the cytosol from the ocular tissue exhibits the nicotinamide N-oxide reductase activity when supplemented with 2-hydroxypyrimidine, an electron donor of aldehyde oxidase. When the cytosol was fractionated with ammonium sulfate, followed by assays of aldehyde oxidase and nicotinamide N-oxide reductase activities in each fraction, the distribution of aldehyde oxidase activity in the resultant ammonium sulfate fractions was nearly parallel to that of nicotinamide N-oxide reductase activity. Furthermore, reductase activities towards drugs such as sulfoxide, hydroxamic acid and nitro compounds were observed with the cytosol in the presence of 2-hydroxypyrimidine or N1-methylnicotinamide. In general, these reductase activities of the fraction were markedly inhibited by menadione, an inhibitor of aldehyde oxidase. These results suggest that aldehyde oxidase present in ciliary body plays an important role in the reduction of a variety of xenobiotics in mammalian eyes. However, in the case of imipramine N-oxide, its reduction in the ocular tissue appears to be more readily catalyzed by a menadione-linked enzyme different from aldehyde oxidase.

Aldehyde Oxidoreductases↗
PubMed1988

[Study of imipenem/cilastatin sodium in the perinatal period].

The placental passage and therapeutic efficacy of imipenem/cilastatin sodium (IPM/CS) were studied in the perinatal period. The results obtained are summarized as follows: 1. The mean biological half-life of IPM in maternal serum was 30 minutes. 2. The umbilical cord serum concentration of IPM was about 70% of that in maternal serum after 30 minutes. 3. A significant level of IPM was found in the amniotic fluid. The amniotic fluid concentration of IPM was over 1 micrograms/ml at 45 minutes after administration and equal to that in maternal serum at about 90 minutes. 4. In 4 patients, the time course of placental transfer of IPM was investigated. The level of IPM in amniotic fluid was higher than that in maternal serum at 90 minutes after administration and gradually increased afterward. 5. The level of IPM was 3.96 micrograms/g in the fetal membranes at 17 minutes after administration. 6. In the treatment of 12 patients with perinatal infections, the preparation showed excellent efficacies in 3 patients and good efficacies in 7 patients. 7. An adverse effect (vomiting) was observed in only one patient. In conclusion, this drug showed satisfactory placental transfer as well as sufficient safety and excellent efficacy in the treatment of perinatal infections.

Adult↗
PubMed1988

Excellent patency and growth potential of internal mammary artery grafts in pediatric coronary artery bypass surgery. New evidence for a "live" conduit.

Coronary artery bypass grafting in pediatric patients provides a unique opportunity to evaluate the characteristics of graft material. Twelve pediatric patients with severe coronary artery involvement secondary to Kawasaki disease underwent coronary artery bypass grafting with internal mammary artery and autologous saphenous vein grafts. Eleven patients were boys and one was a girl; their ages ranged from 5 to 13 years (mean age +/- SD, 8.7 +/- 3.0 years). These 12 patients had 17 internal mammary artery and 11 autologous saphenous vein grafts with a mean value of 2.3 +/- 0.7 grafts per patient. Five patients underwent bilateral internal mammary artery grafting with or without concomitant autologous saphenous vein grafting. There was no mortality, and all patients are leading almost normal lives, although strenuous exercise is still prohibited for some. Biplanar cineangiography was performed before and 1 month after (early postoperative period) coronary artery bypass grafting in all patients and was repeated more than 1 year after (late postoperative period) bypass in eight patients. Changes in graft diameter and graft length were assessed by computer-assisted graphic analysis of 10 internal mammary artery grafts and of seven saphenous vein grafts between the early and late postoperative periods. Patency rates of saphenous vein grafts and of internal mammary artery grafts were 91% and 100%, respectively, at the early postoperative period (p = NS), and 50% and 100%, respectively, at the late postoperative period (p less than 0.05). In addition to the excellent patency of internal mammary artery grafts in the late postoperative period, an in situ internal mammary artery graft was found to have grown 125% in length with 112% body growth (112% body surface area) (r = 0.88, p less than 0.001) and to have enlarged 149% in diameter when the native coronary stenosis was tight. In contrast, the lengths of saphenous vein grafts either failed to change or were slightly decreased at the late postoperative period (p = NS). Growth potential of the internal mammary artery graft provides a new demonstration of the viability and adaptability of this graft. We conclude that the internal mammary artery graft is a "live" conduit with potential for growth and adaptation. This growth potential may be the most important reason for its excellent long-term patency, which suggests that in situ internal mammary artery grafts are the graft of choice for pediatric coronary artery bypass grafting.

Adolescent↗