Biomedical subjects

N Tsutsui

Publications and source records attributed to N Tsutsui.

26 records · Page 2Linked to original sources

PubMed1985

[Adjusted relative survival rate and causes of death after resection of gastric cancer].

To estimate how many of 1,302 patients with curative resection of gastric cancer died of recurrence or other diseases, the cumulative survival rate (act), relative survival rate (rl) and adjusted relative survival rate (adj) were analyzed. Adj was computed excluding gastric cancer death, because the death rate of this disease can not be ignored in the Japanese population. The death rate from gastric cancer can be estimated by [1.0-(adj)] and that from other causes by [(adj)-(act)]. It is more appropriate to calculate adj for the patients with mucosal or submucosal cancer, and rl can be substituted for adj for those with deeper invasion.

Adult↗

PubMed1984

[Adjuvant chemotherapy after surgery in advanced gastric cancer].

Two hundred and fifty-four patients with advanced gastric cancer underwent radical surgery and ftorafur (FT) or 5-fluorouracil (5-FU) was orally administered as the adjuvant chemotherapy (ACT). Recurrence after ACT were analyzed by the quantification method II. As a result, it was found that: 1) ACT over 2 years could lower the recurrence rate, and careful follow-up is still necessary up to 4 years, and 2) after the remission induction therapy with mitomycin C and/or 5-FU and cytarabine, 12 mg/kg/day of FT for the first year and 8 mg for the second year are advisable.

Administration, Oral↗

PubMedDate not supplied

Suppression of in vitro IFN-gamma production by spleen cells of Plasmodium chabaudi-infected C57BL/10 mice exposed to dexamethasone at a low dose.

After infection with Plasmodium chabaudi, C57BL/10 mice produced significant amounts of serum IFN-gamma, developed a low level of parasitemia and survived the infection. Production of IFN-gamma was also obvious when spleen cells of the infected mice were stimulated with the parasite antigen contained in an erythrocyte lysate in vitro. Depletion of CD4+ T cells abrogated production of IFN-gamma, leading to loss of resistance to the infection. The CD4+ T cells/IFN-gamma-dependent resistance of the C57BL/10 mice against P. chabaudi was applied to assess immunotoxicological effect of dexamethasone (DEX). Administration of a high dose (0.75 mg/kg) resulted in loss of the splenic cellularity, remarkable decrease in serum IFN-gamma production, increased level of parasitemia, and eventual death of the infected mice. In contrast, DEX at a low dose (0.02 mg/kg) induced no alternation in the in vivo host immune activity and the mice survived the infection. However, when spleen cells were obtained from the infected mice administered the low dose of DEX and stimulated in vitro with the parasite antigen, a significantly decreased level of IFN-gamma was demonstrated with compared to control mice. These findings demonstrate that the in vitro production of IFN-gamma by spleen cells from P. chabaudi-resistant C57BL/10 mice was more sensitive to the immunosuppressive effect of in vivo administration of DEX. This ex vivo assay might provide a method for evaluation of drug-induced immunotoxicity at a higher sensitivity than the conventional host resistant assays such as comparison of severity of disease or time to death.

Animals↗

PubMedDate not supplied

Applicability of the latissimus dorsi muscle in situ as a biomechanical energy source.

The purpose of this study was to assess the applicability of the latissimus dorsi muscle in situ as an energy source for a circulatory assist device. A pneumatic chamber, devised by the authors, was inserted beneath the muscle and compressed by contractions of the muscle so that muscle contractile power was converted into pneumatic pressure. The optimal insertion position of the chamber beneath the latissimus dorsi muscle, and the influence of chamber size on generated pneumatic pressure, were investigated. The pneumatic chamber functioned better when it was placed in a proximal position (third intercostal space) than in a middle or distal position. Using a mock circuit, the performance of the pneumatic chamber as an energy source for a circulatory assist device was evaluated. The pneumatic chamber was able to generate power sufficient to drive a right ventricular assist device as far as stroke work was involved. When the pneumatic chamber was operated with a high afterload, it could even be an energy source for aortic counterpulsation.

Animals↗

PubMedDate not supplied

A compressive type skeletal muscle pump as a biomechanical energy source.

The purpose of this study was to assess the applicability of the conditioned latissimus dorsi muscle as an energy source for circulatory assist devices. The authors developed a pneumatic chamber as a muscle actuator. The pneumatic chamber placed between latissimus dorsi muscle and chest wall was compressed by the burst stimulated muscle and, thereby, converted muscle contractile power into pneumatic pressure. The authors report the performance of the implanted pneumatic chamber at a chronic phase, and the capability of the conditioned muscle in situ as an energy source for circulatory assist devices. Six adult mongrel dogs were used. At the first operation, a pacemaker for muscle conditioning and the pneumatic chamber were implanted. After 12 weeks of muscle conditioning, the performance of the pneumatic chamber with conditioned muscle was evaluated. The pressure generating capability of a chamber buried in fibrous adhesions was reduced to approximately 65% of that of a chamber without adhesions. The stroke volume and stroke work of the assist device driven by the developed pneumatic pressure were measured. The maximum stroke work of the circulatory assist was greater than the stroke work of the right ventricle, but less than that of the left ventricle. In respect to stroke volume, the pneumatic chamber could drive the circulatory assist device against not only a pulmonary range of afterload, but also a systemic range of afterload, when high pre load was available. These results indicate that the compressive skeletal muscle pump with conditioned latissimus dorsi muscle generates acceptable hemodynamic work for right ventricular bypass or aortic counterpulsation. In the long-term, the interface between tissue and actuator is the major obstacle to developing a muscle powered assist device.

Animals↗

PubMedDate not supplied

A new endo aortic occlusion balloon for limited access cardiac surgery: development and clinical evaluation.

In recent years, minimally invasive cardiac surgery (MICS), or limited access cardiac surgery, has been presented as a promising operative procedure. We developed a new balloon device that is inserted directly into the ascending aorta to stop the heart during limited access cardiac surgery. The balloon has a three lumen structure: balloon lumen port, cardioplegia/vent lumen port, and aortic root lumen port. This direct EAC balloon catheter, designed to be inserted directly into the ascending aorta, is different from the Heartport system. The Heartport EAC balloon catheter is inserted into the aorta via an artery in the lower limb, making lower limb arterial disease a key concern. Our Direct Endo Aortic Clamp (EAC) balloon overcomes this problem. The device was clinically used in seven cardiac cases. All patients were discharged within 5 postoperative days, confirming the utility of the device.

Aorta↗

PubMedDate not supplied

Experimental study of extraaortic balloon counterpulsation as a bridge to other mechanical assists.

A special extraaortic balloon was developed that can be placed around the ascending aorta. This balloon can easily support the heart temporarily in a median sternotomy field, especially in cases in which it is difficult to use intraaortic balloon pumping because of peripheral arterial disease. The goal of this study was to judge the applicability of this extraaortic balloon counterpulsation. An extraaortic balloon was placed around the ascending aorta of eight adult canines. Two heart failure models were used in this study: group A-moderate heart failure; group B-severe heart failure. In group A, the aortic systolic pressure was significantly reduced (9.3%, p < 0.01), but in group B, there was no significant change. In group A, there was a significant increase in cardiac output (12.0%, p < 0.01), but in group B, there was no significant change. The endocardial viability ratio in both groups significantly increased (group A: 11.3%, p < 0.01; group B: 11.9%, p < 0.05). An extraaortic balloon around the ascending aorta is easily applicable through a median sternotomy, and can be used as a bridge to more powerful mechanical assists when intraaortic balloon pumping cannot be used.

Animals↗

PubMedDate not supplied

Experimental study of combination of extraaortic balloon counterpulsation and ventricular assist cup to acute heart failure in dogs.

The goal of this study is to evaluate the applicability and effectiveness of combination support of the extraaortic balloon (EAB) and the ventricular assist cup (VAC) to the acute heart failure model. Under general anesthesia, 10 adult dogs were used. Through the median sternotomy, EAB was placed around the ascending aorta and VAC in the pericardial cavity. After heart failure was induced by administration of propranolol, the on-off tests of devices were done as follows. Only EAB was used, and only VAC was used and both devices were used. Regional blood flows (RBFs) of both ventricles, liver kidneys, and brain were measured by colored microsphere technique. Hemodynamic parameters were also measured. In heart failure model, cardiac output (CO) decreased to 66% of control value. In the group assisted by EAB, aortic peak-diastolic pressure and RBFs of both ventricle and brain increased significantly. In the group assisted by VAC, CO and RBFs of all but the left ventricle significantly increased. In the group assisted by EAB and VAC, aortic peak-diastolic pressure, CO, and all five RBFs significantly increased. These results suggest the combination of EAB and VAC is applicable and effective and would be a promising implantable device for the chronic heart failure.

Acute Disease↗