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S Ohtsuka

Publications and source records attributed to S Ohtsuka.

At least 19 recordsLinked to original sources
PubMed1998

Randomized, double-blind, placebo-controlled study of ascorbate on the preventive effect of nitrate tolerance in patients with congestive heart failure.

BACKGROUND: Reduced cGMP production caused by increased superoxide has been proposed as a mechanism of nitrate tolerance during continuous nitrate therapy. This study was designed to evaluate the effects of ascorbate, an antioxidant, on the development of nitrate tolerance during continuous nitrate therapy in patients with congestive heart failure. METHODS AND RESULTS: Twenty patients with congestive heart failure were randomized to receive intravenous infusion of nitroglycerin concomitantly with placebo (placebo group, n=10) or intravenous ascorbate (vitamin C group, n=10). After baseline measurements were obtained, dose titration was started by the infusion of nitroglycerin at a rate of 0.5 microg/kg per minute (titration period). Measurements of hemodynamic parameters and blood sampling were performed serially at 0, 6, 12, 18, and 24 hours after the titration period. At baseline, mean pulmonary artery pressure (MPAP, mm Hg), mean pulmonary capillary wedge pressure (PCWP, mm Hg), plasma vitamin E level (micromol/L), and platelet cGMP level (pmol/10[9] platelets) were comparable in the two groups (placebo group: MPAP, 48+/-6; PCWP, 24+/-4; cGMP, 0.76+/-0.12; vitamin E, 18.2+/-1.2; vitamin C: MPAP, 49+/-7; PCWP, 24+/-4; cGMP, 0.71+/-0.16; vitamin E, 18.6+/-1.3). In both groups, at 6 hours after the titration period, MPAP and PCWP were significantly decreased (placebo group: MPAP, 26+/-5; PCWP, 15+/-4; vitamin C: MPAP, 26+/-4; PCWP, 16+/-4), and platelet cGMP was significantly increased (placebo group: 2.42+/-0.24; vitamin C: 2.26+/-0.26). However, at 18 hours after titration, in the placebo group, MPAP (44+/-5) and PCWP (23+/-4) were increased, and platelet cGMP (0.85+/-0.20) and plasma vitamin E levels (12.4+/-1.4) were significantly decreased. In contrast, in the vitamin C group, MPAP (31+/-6), PCWP (17+/-5), platelet cGMP (2.49+/-0.23), and plasma vitamin E levels (17.6+/-1.4) were maintained for 18 hours after the titration period. CONCLUSIONS: These findings indicate that ascorbate, an antioxidant, may prevent the development of nitrate tolerance during continuous nitrate therapy in patients with congestive heart failure.

Aged↗
PubMed1998

Endobronchial metastasis from rectal adenocarcinoma: report of a case.

We herein report a case of late endobronchial metastasis after the resection of a primary rectal adenocarcinoma. A 51-year-old man underwent a resection of rectal adenocarcinoma. Five years postoperatively, he underwent a right sleeve upper lobectomy for a right endobronchial tumor. The resected tumor was diagnosed to be endobronchial metastasis from rectal adenocarcinoma. Therefore, the relationship between the two tumors was analyzed using deoxyribonucleic acid (DNA) flow cytometry and immunohistochemical staining. Endobronchial adenocarcinoma had strong homogeneous staining patterns and identical biochemical characteristics to rectal adenocarcinoma.

Adenocarcinoma↗
PubMed1998

Randomized, double-blind, placebo-controlled study of the preventive effect of supplemental oral vitamin C on attenuation of development of nitrate tolerance.

OBJECTIVES: This study sought to evaluate the preventive effect of vitamin C, an antioxidant, on the development of nitrate tolerance. BACKGROUND: Decreased intracellular production of cyclic guanosine monophosphate (cGMP) is a mechanism of nitrate tolerance, and increased superoxide levels and reduced activation of guanylate cyclase have been observed in vitro. METHODS: In this double-blind, placebo-controlled study, 24 normal volunteers and 24 patients with ischemic heart disease (IHD) were randomized to receive either vitamin C (2 g three times daily [vitamin C group, n=12]) or placebo (placebo group, n=12). The vasodilator response to nitroglycerin was assessed with forearm plethysmography by measuring the change in FBF before and 5 min after sublingual administration of 0.3 mg of nitroglycerin. Blood samples were simultaneously obtained to measure platelet cGMP levels. FBF was measured, and blood sampling was performed serially at baseline (day 0), 3 days after administration of vitamin C or placebo (day 3) and 3 days after application of a 10-mg/24-h nitroglycerin tape concomitantly with oral vitamin C or placebo (day 6). RESULTS: There were no differences between the vitamin C and placebo groups in percent increases in FBF (%FBF) or platelet cGMP levels (%cGMP) after administration of sublingual nitroglycerin on day O (%FBF: normal volunteers 31+/-8 vs. 32+/-10; patients with IHD 32+/-9 vs. 32+/-8; %cGMP: normal volunteers 37+/-9 vs. 39+/-10; patients with IHD 38+/-10 vs. 39+/-10 [vitamin C group vs. placebo group]) or day 3 (%FBF: normal volunteers 32+/-9 vs. 33+/-9; patients with IHD 31+/-10 vs. 31+/-10; %cGMP: normal volunteers 36+/-8 vs. 37+/-9; patients with IHD 39+/-11 vs. 38+/-10 [vitamin C group vs. placebo group]). The %FBF and %cGMP in the placebo group were significantly lower on day 6 than in the vitamin C group (%FBF: normal volunteers 30+/-8 vs. 19 4, p < 0.01; patients with IHD 29+/-9 vs. 17+/-6, p < 0.01; %cGMP: normal volunteers 36 10 vs. 17+/-6, p < 0.01; patients with IHD 37+/-11 vs. 15+/-5, p < 0.01 [vitamin C group vs. placebo group]). CONCLUSIONS: These results indicate that combination therapy with vitamin C is potentially useful for preventing the development of nitrate tolerance.

Adult↗
PubMed1998

Intravenous injection with antisense oligodeoxynucleotides against angiotensinogen decreases blood pressure in spontaneously hypertensive rats.

In the renin-angiotensin system, renin is known to cleave angiotensinogen to generate angiotensin I, which is the precursor of angiotensin II. Angiotensin II is a vasoactive peptide that plays an important role in blood pressure. On the other hand, the liver is the major organ responsible for the production of angiotensinogen in spontaneously hypertensive rats (SHR). To test the hypothesis that a reduction of angiotensinogen mRNA in the liver by antisense oligodeoxynucleotides (ODNs) may affect both plasma angiotensinogen and angiotensin II levels, as well as blood pressure, we intravenously injected antisense ODNs against rat angiotensinogen coupled to asialoglycoprotein carrier molecules, which serve as an important regulator of liver gene expression, into SHR via the tail vein. The SHR used in the present study were studied at 20 weeks of age and were fed a standard diet throughout the experiment. Plasma angiotensinogen, angiotensin II concentrations, and blood pressure all decreased from the next day until up to 5 days after the injection of antisense ODNs. These concentrations thereafter returned to baseline by 7 days after injection. A reduction in the level of hepatic angiotensinogen mRNA was also observed from the day after injection until 5 days after injection with antisense ODNs. However, in the SHR injected with sense ODNs, plasma angiotensinogen, angiotensin II concentrations, and blood pressure, as well as hepatic angiotensinogen mRNA, did not significantly change throughout the experimental period. Although the exact role of angiotensinogen in hypertension still remains to be clarified, these findings showed that intravenous injection with antisense ODNs against angiotensinogen coupled to asialoglycoprotein carrier molecules targeted to the liver could thus inhibit plasma angiotensinogen levels and, as a result, induce a decrease in blood pressure in SHR.

Angiotensinogen↗
PubMed1998

[Randomized, double-blind, placebo-controlled study of supplemental vitamin E on attenuation of the development of nitrate tolerance].

The attenuation of intracellular production of cyclic guanosine monophosphate (cGMP) has been known as a mechanism of nitrate tolerance. A recent in vitro study have shown an increase in superoxide levels and a reduced activation of guanylate cyclase in tolerant vessels. We investigated the preventive effect of an antioxidant, vitamin E, on the development of nitrate tolerance. In this double-blind, placebo-controlled study, 24 normal volunteers and 24 patients with ischemic heart disease (IHD patients) were randomized to receive either vitamin E (200 mg t. i. d.; vitamin E group) or placebo (placebo group). Vasodilator response to nitroglycerin was assessed with forearm plethysmography by measuring the change in the forearm blood flow before and 5 min after sublingual administration of 0.3 mg nitroglycerin, and at the same time, blood samples were taken from veins to measure the platelet cGMP level. Measurements of the forearm blood flow and blood sampling were obtained serially at baseline (day 0), 3 days after taking vitamin E or placebo alone (day 3), and 3 days after application of a 10 mg/24 hr nitroglycerin tape concomitantly with oral vitamin E or placebo (day 6). The response of forearm blood flow (%FBF) and cGMP (%cGMP) after sublingual nitroglycerin on day 0(%FBF: normal volunteers 32 +/- 12% vs 31 +/- 11%, IHD patients 35 +/- 15% vs 34 +/- 15%; %cGMP: normal volunteers 38 +/- 10% vs 35 +/- 11%, IHD patients 37 +/- 11% vs 38 +/- 12%; vitamin E group as placebo group) and day 3(%FBF: normal volunteers 33 +/- 9% vs 32 +/- 12%, IHD patients 35 +/- 12% vs 33 +/- 13%, %cGMP: normal volunteers 38 +/- 10% vs 37 +/- 11%, IHD patients 36 +/- 14% vs 37 +/- 10%, vitamin E group vs placebo group) were not different between the two groups. On day 6 %FBF and %cGMP in the placebo group were significantly lower compared with day 0, and there were significant differences in them between the two groups (%FBF: normal volunteers 30 +/- 12% vs 17 +/- 9%, p < 0.01; IHD patients 28 +/- 14% vs 17 +/- 8%, p < 0.01; %cGMP: normal volunteers 35 +/- 11% vs 8 +/- 5%, p < 0.01; IHD patients 38 +/- 10% vs 12 +/- 4%, p < 0.01, vitamin E group vs placebo group). In conclusion, the combination therapy with vitamin E is potentially a useful method to prevent the development of nitrate tolerance.

Aged↗
PubMed1997

Randomized, double-blind, placebo-controlled study of supplemental vitamin E on attenuation of the development of nitrate tolerance.

BACKGROUND: The attenuation of intracellular production of cGMP has been known to be a mechanism of nitrate tolerance. A recent in vitro study showed an increase in superoxide levels and a reduced activation of guanylate cyclase in tolerant vessels. We investigated the preventive effect of an antioxidant, vitamin E, on the development of nitrate tolerance. METHODS AND RESULTS: In this double-blind, placebo-controlled study, 24 normal volunteers and 24 patients with ischemic heart disease (IHD patients) were randomized to receive either vitamin E (200 mg TID vitamin E group) or placebo (placebo group). Vasodilator response to nitroglycerin was assessed with forearm plethysmography by measurement of the change in the forearm blood flow before and 5 minutes after sublingual administration of 0.3 mg nitroglycerin, and at the same time, blood samples were taken from veins to measure the platelet cGMP level. Measurements of the forearm blood flow and blood sampling were obtained serially at baseline (day 0), 3 days after vitamin E or placebo alone was taken (day 3), and 3 days after application of a 10-mg/24-h nitroglycerin tape concomitantly with oral vitamin E or placebo (day 6). The responses of forearm blood flow (%FBF) and cGMP (%cGMP) after sublingual nitroglycerin on day 0 (%FBF: normal volunteers, 32+/-12 versus 31+/-11; IHD patients, 35+/-15 versus 34+/-15; %cGMP: normal volunteers, 38+/-10 versus 35+/-11; IHD patients, 37+/-11 versus 38+/-12, vitamin E group versus placebo group) and day 3 (%FBF: normal volunteers, 33+/-9 versus 32+/-12; IHD patients, 35+/-12 versus 33+/-13; %cGMP: normal volunteers, 38+/-10 versus 37+/-11; IHD patients, 36+/-14 versus 37+/-10, vitamin E group versus placebo group) were not different between the two groups. On day 6, %FBF and %cGMP in the placebo group were significantly lower compared with day 0, and there were significant differences in them between the two groups (%FBF: normal volunteers, 30+/-12 versus 17+/-9, P<.01; IHD patients, 28+/-14 versus 17+/-8, P<.01; %cGMP: normal volunteers, 35+/-11 versus 8+/-5, P<.01; IHD patients, 38+/-10 versus 12+/-4, P<.01, vitamin E group versus placebo group). CONCLUSIONS: These results indicate that the combination therapy with vitamin E is potentially a useful method to prevent the development of nitrate tolerance.

Administration, Oral↗
PubMed1997

Effects of enalapril during continuous nitrate therapy: analysis of diameter of coronary arteries and platelet cyclic guanosine monophosphate.

To investigate the effects of enalapril, an angiotensin-converting enzyme inhibitor, on nitrate tolerance during continuous nitrate therapy, coronary artery diameters and platelet cyclic guanosine monophosphate (cGMP) levels were measured before and 2 minutes after intracoronary injection of nitroglycerin 200 microg in 60 patients with coronary artery disease and were compared among 20 patients treated with nitrates (nitrate group), 20 patients treated with both nitrates and enalapril (enalapril group), and 20 untreated patients (control group). The percent increase in platelet cGMP and coronary dilatation in the nitrate group was significantly less than in the control group, but the percent increase in the enalapril group was significantly greater than that in the nitrate group. These results indicate that enalapril may be helpful as concomitant therapy to maintain the effect of nitrates during continuous nitrate therapy.

Aged↗
PubMed1997

Experience of expandable metallic stents for central airway obstruction.

The aim of this study was to investigate retrospectively the efficacy of expandable metallic stents (EMSs) for severe respiratory distress in patients with central airway obstruction. Twenty patients with central airway obstructions were treated with an EMS. An intraluminal stricture was present in 15 and an extraluminal stricture in 5 patients. Of the 15 patients with intraluminal stenosis, 11 exhibited symptomatic improvement. All 11 patients had tumor infiltration occupying less than 50% of the endoluminal diameter. The other four patients with intraluminal stenosis had tumor infiltration occupying > 50% of the endoluminal diameter and demonstrated no improvement. All five patients with extraluminal stenosis were improved. EMS is useful for an extraluminal stricture in the central airway and the effect of EMS for intraluminal stenosis is related to the degree of infiltration and of tumor progression itself.

Adult↗