Biomedical subjects

Shin Saito

Publications and source records attributed to Shin Saito.

22 records · Page 2Linked to original sources

PubMed2002

Viscoelastic effects in relaxation processes of concentration fluctuations in dynamically asymmetric polymer blends.

Relaxation processes of the concentration fluctuations induced by a rapid pressure change were investigated for a dynamically asymmetric polymer blend [deuterated polybutadiene (DPB)/polyisoprene (PI)] with a composition of 50-50 by weight by using time-resolved small-angle neutron scattering. The pressure change was carried out inside the single-phase of the blend with the cell designed for polymeric systems under high pressure and temperature. Time change in the scattered intensity distribution with wave number (q) during the relaxation processes was found to be approximated by Cahn-Hilliard-Cook linearized theory. The theoretical analysis yielded the q dependence of Onsager kinetic coefficient that is characterized by the q(-2) dependence at q(xi)(ve)>1 with the characteristic length xi(ve) (with xi(ve) being the viscoelastic length) being much larger than radius of gyration of DPB or PI. The estimated xi(ve) agrees well with that calculated using the Doi and Onuki theory that takes into account the viscoelastic effects arising from the dynamical asymmetry between the component polymers in the relaxation of concentration fluctuations.

Journal Article↗

PubMed2002

[Every-other-day TS-1 administration for recurrent or non-curative advanced gastric carcinoma].

We report 3 cases in which palliation was achieved with every-other-day administration of TS-1 for recurrent or non-curative advanced gastric carcinoma that had resulted in obstructive jaundice. Two patients had received MTX-5-FU chemotherapy as first-line therapy and showed progressive disease, presenting with obstructive jaundice 6-24 months later. One of them experienced obstructive jaundice 2 months after surgery. After lowering serum bilirubin via per-cutaneous transhepatic biliary drainage (PTBD), TS-1 was given not in full dose but every other day based upon Shirasaka's theory, as well as for fear of further liver damage. Palliation in terms of long NC and/or decreased serum CEA level persisted for 4-14 months without severe liver dysfunction. Other side effects of the drug were negligible. Shirasaka's theory stresses the difference in proliferation cycles between cancer cells and normal tissue cells (GI tract, bone marrow, etc.); therefore, with every-other-day administration of chemotherapeutic agents, the cytotoxic effects against tumors would be augmented while the adverse reactions in normal cells could be reduced. The present experience seems to support the theoretical and clinical feasibility of every-other-day TS-1 administration for unresectable gastric cancer.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed2002

[Angina attack caused by 5-fluorouracil infusion--report of a case and review of the literature].

Cardiac toxicity of 5-fluorouracil (5-FU) has been rarely reported. We encountered a case of angina attack caused by 5-FU. A 58-year-old Japanese woman underwent sigmoidectomy for a sigmoid colon carcinoma with multiple liver metastases. Two months after surgery, she received chemotherapy comprising hepatic arterial infusion of 5-FU. During the 2nd chemotherapy session 7 days after the first, she complained of anterior chest pain. Her electrocardiograms showed elevations of the ST segment in almost all leads, confirming the diagnosis of angina pectoris. Soon after the third chemotherapy session the same type of attack occurred again. The close association of the attacks with 5-FU administration suggested that the angina might have been induced by 5-FU. Further attacks were avoided by discontinuing the 5-FU thereafter. The incidence of cardiac toxicity 5-FU has been reported to be 1.6-7.6%. Labianca et al. found 17 cases of 5-FU-associated cardiopathy, 15 of which were angina pectoris, out of 1,083 patients treated with the drug for various kinds of neoplasm. Analysis of 6 domestic cases including ours revealed that all patient lacked a previous history of cardiac disease except one who had an arrhythmia. There seemed to be no dose-dependent correlation with 5-FU-induced angina. Cardiac events were found even in the earlier phase of chemotherapy. Since 5-FU is widely used in the treatment of a number of gastrointestinal malignancies, one should bear in mind its cardiac toxicity, manifested as angina pectoris.

Angina Pectoris↗

PubMedDate not supplied

Predicting glaucomatous sensitivity loss using perimetric color saturation test.

PURPOSE: To predict future glaucomatous sensitivity loss using a perimetric color saturation test (PCST) that measures the color saturation discrimination threshold for six hues (red, yellow, green, green-blue, blue, and purple) at 9 degrees in horizontal and 3 degrees in vertical extrafoveal points. METHODS: This new test was carried out on 31 patients (31 eyes) with early glaucoma or ocular hypertension. The sensitivity loss at the four points approximately 9.5 degrees apart from the fixation point was prospectively evaluated annually for 3 years using the Humphrey Field Analyzer (HFA) program central 30-2. The initial results of PCST and the total deviation (TD) in the follow-up HFA results were compared. RESULTS: Twenty-seven patients (27 eyes) were followed up for 3 years. The color saturation threshold for six hues was correlated with the TD of HFA results at 108 points in the 27 eyes. The TD was -4 dB or better at the baseline measurement in 91 out of the 108 points. The averaged TD in the second and the third year in the follow-up period decreased below -4 dB in 10 of these 91 points, which were categorized as progression points in relation to the 81 nonprogression points. In the initial PCST, only the saturation threshold for purple was higher in the progression points when compared with the nonprogression points (P=.0004, Mann-Whitney U-test). CONCLUSION: Future sensitivity loss is most likely at the points where the threshold of color saturation discrimination is increased for purple in eyes with early glaucoma or ocular hypertension.

Adult↗