Super-elasticity and thermal behavior of Ni-Ti alloy orthodontic arch wires.

Bending properties and thermal behavior of twenty commercial Ni-Ti alloy orthodontic arch wires were investigated quantitatively to characterize their suitability for clinical use. There was substantial difference among the load-deflection curves obtained by a three-point bending test. Some wires exhibited super-elasticity; load decreased little with decreasing deflection. Others showed good spring-back properties only; load was nearly proportional to deflection. Thermal behavior due to phase transformation of the alloy was examined by differential scanning calorimetry (DSC). Some of the wires did not have the correct transformation temperatures to exhibit super-elasticity at body temperature. Moreover, thermal behavior was closely related to super-elasticity. There were clear thermal peaks in the DSC curves of the super-elastic wires. However, wires without super-elasticity had no peak in the DSC curves.     

Efficacy of oral UFT as adjuvant chemotherapy to curative resection of colorectal cancer: multicenter prospective randomized trial

BACKGROUND: The purpose of this study is to evaluate the efficacy of postoperative adjuvant chemotherapy using uracil and tegafur (UFT) for colorectal cancer. METHODS: In a multicenter trial among 43 institutions for patients who underwent curative resection of Dukes' B or C colorectal cancer, a surgery alone group (control group) and a treatment group (UFT group) to which UFT was administered at 400 mg/day for 2 years following surgery were compared. A total of 320 patients were registered between March 1991 and April 1994, and 289 of these patients were analyzed as a full-analysis set. RESULTS: The 5-year disease-free survival rate was 75.7% in the UFT group and 60.1% in the control group, respectively, and the stratified log-rank test showed the statistical significance ( P=0.0081). This difference was marked in rectal cancer ( P=0.0016) and, in particular, the local recurrence was reduced. No significant difference was observed in the 5-year survival rate. The incidence of adverse reactions on administration of UFT was low, and there was no serious adverse reaction. CONCLUSION: It is suggested that the consecutive administration of UFT at 400 mg/day was an effective and highly safe therapeutic method as postoperative adjuvant chemotherapy for rectal cancer.     

Histological evaluation of intra-arterial infusion and systemic chemotherapy of pancreatic carcinomas]

Histological analyses of 16 autopsies of pancreatic carcinoma [9 cases after intra-arterial infusion chemotherapy (IAC), and 7 cases of systemic chemotherapy (SC)] were performed. Histological effects of chemotherapy (Shimosato) were seen in 15 cases, but less than 5 Grade II a. cases of IAC and 4 cases of SC showed Grade IIa, 3 cases of IAC and 3 cases of SC showed Grade I. The ratio of Grade IIa was almost the same in IAC and SC. But histologically, anaplastic change, sarcomatous change and Bizarre cells, immunohistologically positive to anti-EMA and Vimentin antibody, were dominant in IAC. And clinically, serum tumor markers (CEA, CA19-9) were fewer in almost all the cases in IAC. These results may suggest that the anti-tumor effect of IAC was greater than the histological appearance.     

INFLUENCE OF WORKLOAD ON THE ANTIHYPERTENSIVE EFFECT OF EXERCISE

1. The relation between workload and the antihypertensive effect of exercise therapy in hypertensive patients, and the mechanism of that effect, were investigated. 2. Twenty-six patients participated in the study and were randomly assigned to 10 weeks of either low or high workload exercise. In the low workload group, 16 mild hypertensive patients were treated with bicycle ergometer exercise at approximately 50% of their maximum oxygen consumption (VO2max) for 60 min three times a week for 10 weeks. In the high workload group, 10 mild hypertensive patients exercised on the same schedule, but at approximately 75% of VO2max. 3. After 10 weeks of exercise, the low workload group had significantly lower systolic (9 mmHg), mean (6 mmHg) and diastolic (6 mmHg) blood pressures. In the high workload group, decreases in systolic (3 mmHg), mean (4 mmHg) and diastolic (5 mmHg) blood pressure were not statistically significant. 4. In the low workload group, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 7. Cardiac index and plasma norepinephrine tended to decrease. In the high workload group, plasma norepinephrine and the renin-angiotensin system were transiently stimulated after 4 weeks of exercise. Stroke volume significantly increased (+26.4%) after 10 weeks of high workload exercise. 5. Based on these results and better patient compliance with the exercise programme in the low workload group than in the high workload group, low workload exercise therapy was recommended to mild hypertensive patients.     

Inverse relationship between serum cholinesterase activity and the administration of cyclophosphamide: an Index of cyclophosphamide therapy

To determine whether serum cholinesterase activity can be amonitoring index of cyclophosphamide therapy in patients withsteroid-resistant glomerulopathy, we compared the cholinesteraseactivity of 37 patients who received a combined therapy thatincluded the use of cyclophosphamide, prednisolone, antiplateletdrugs, and anticoagulant drugs, with the cholinesterase activityof 25 patients who received prednisolone therapy that excludedcyclophosphamide from the combined therapy. In the prednisoloneand the combined groups, cholinesterase activity declined asshown in the following formula: Y=371–26.4xlog(X): (r²=0.28),Y=444–147.7xlog(X): (r²=0.95), respectively. (Y: cholinesteraseactivity, X: the day after treatment). In the combined therapygroup, the prevalence of adverse reactions following treatmentin the subgroup below 200 U/I of cholinesterase activity wassignificantly greater (P<0.01) than that in the subgroupabove 200 U/I of cholinesterase activity. However, there wasno significant difference (P<0.25) in the prevalence of adversereactions between the subgroups with more or less than 184 U/Iof cholinesterase activity following treatment. These resultssuggest the importance of not going below 200 U/I of cholinesteraseactivity after treatment when the normal cholinesterase activityrange is between 300 and 760 U/I (e.g. less than 65% of thelowest value of the normal range of other hospitals) in orderto eliminate the hazards of cyclophosphamide to the patientswith steroid-resistant glomerulopathy.     

Radiolucent bone cysts and the type of dialysis membrane used in patients undergoing long-term hemodialysis.

The relationship between the types of dialysis membrane used and the prevalence and severity of radiolucent bone cysts (which are a main radiological feature of dialysis amyloidosis) was studied in 30 patients on hemodialysis for more than 10 years. One of them was treated exclusively with cuprophane; the other 29 were dialyzed with cuprophane, and then treated with polyacrylonitrile AN 69. In 12 of the 30 patients, radiolucent bone cysts (at least 5 mm in diameter in the wrists and at least 10 mm in the shoulders or hips) were observed. The patients with bone cysts spent significantly more time on cuprophane dialysis and significantly less time on AN 69 dialysis than the group of patients without bone cysts. Nine of the 14 patients who had been treated with cuprophane for more than 8 years had bone cysts; whereas bone cysts were observed in only 2 of the 12 patients dialyzed for more than 8 years with AN 69. The frequency of bone cysts was significantly different for each of the two groups. There was, however, no significant difference in the total duration of dialysis between the two groups. The severity of the cystic bone lesions correlated positively with the duration of dialysis using cuprophane and negatively with the duration of dialysis using AN 69. These findings suggest that the development of osteoarticular amyloidosis may be related to the type of dialysis membrane used. Hemodialysis using AN 69 membranes may prevent, or at least postpone the development of dialysis amyloidosis.     

Alteration in surface structure of Clara cells and pulmonary cytochrome P-450b level in rats exposed to ozone.

Changes in the surface structure of Clara cells in the terminal bronchioles following exposure of rats to 0.4 ppm ozone (O3) for 14 days were evaluated and compared to the content of pulmonary cytochrome P-450, an enzyme active in xenobiotic metabolism. Exposure to O3 caused a striking alteration of Clara cells in the terminal bronchiole. After 6 h exposure apical protrusions of Clara cells enlarged and these Clara cells formed clusters. However after 24 h exposure, the Clara cells decreased in number and flattened. They increased in number and enlarged again during the subsequent period of exposure. By the 14th day of O3 exposure the number of Clara cells had increased significantly. The content of cytochrome P-450b (IIB1), a main isozyme of pulmonary cytochromes P-450 of rats, was determined by an immuno-blotting method using anti-cytochrome P-450b antibody. The cytochrome P-450b in the rats exposed to O3 increased significantly to 1.37- and 1.81-times that of the control on the 7th and 14th days, respectively. Immuno-electron microscopy demonstrated that cytochrome P-450b was localized abundantly in endoplasmic reticulum of Clara cells. Morphological alterations in Clara cells appear to be closely related with changes in the cytochrome P-450b content of the lung.     

Lipid peroxidation of rat erythrocyte membrane induced by adriamycin-Fe3+.

Adriamycin-Fe3+ caused lipid peroxidation of erythrocyte membrane in relation to its concentration. Adriamycin-Fe3+ had a high affinity for membrane and the adriamycin-Fe(3+)-binding membranes membranes was also found to cause lipid peroxidation. Under aerobic conditions, adriamycin-Fe3+ caused a reduction of cytochrome c and ferrous iron formed spontaneously. Superoxide dismutase (EC 1.15.1.1) (SOD) strongly inhibited the reduction of cytochrome c; however, the enzyme promoted formation of ferrous iron independent of enzymatic action. These results suggest that cytochrome c was reduced by superoxide radical (O2-) or an adriamycin-iron-O2 complex such as adriamycin-Fe(3+)-O2-, but not by adriamycin-Fe2+. The ferrous iron chelator bathophenanthroline sulfonate (BPS) completely inhibited oxygen consumption caused by adriamycin-Fe3+, indicating that ferrous iron is absolutely required for the lipid peroxidation. SOD and hydroxyl radical scavengers did not inhibit the lipid peroxidation, indicating that O2- and hydroxyl radical were not involved in membrane peroxidation. The peroxidation reaction was dramatically inhibited by Tris buffer (2-amino-2-hydroxymethyl-1,3-propanediol). However, hydroxyl radical generation and lipid peroxidation in Tris buffer were not related obviously, indicating that Tris did not act as a hydroxyl radical scavenger. The initial rate of TBARS (thiobarbituric acid reactive substances) formation induced by a mixture of adriamycin-Fe3+ and adriamycin-Fe2+ was much faster than that induced by adriamycin-Fe2+ or adriamycin-Fe3+ alone. These results made it became possible to speculate that the lipid peroxidation might be initiated by an adriamycin-Fe(3+)-oxygen-adriamycin-Fe2+ complex.