Search PubMed⌕ Search

Biomedical subjects

Y Tsutsui

Publications and source records attributed to Y Tsutsui.

121 records · Page 7Linked to original sources
PubMedDate not supplied

Mutagenicity and cytotoxicity of naphthoquinones for Ames Salmonella tester strains.

The molecular mechanisms involved in quinone cytotoxicity, especially mutagenicity, are still largely unknown. In order to better understand the molecular aspects of the mechanisms of quinone mutagenicity and cytotoxicity, we examined them by using a series of 13 simple structural naphthoquinone (NQ) derivatives for 9 Ames Salmonella mutagenicity tester strains in the presence of absence of liver homogenate S9 mix from rats induced with phenobarbital and 5,6-benzoflavone. Most NQs used in this study showed mutagenicity with and/or without S9 mix. The most potent mutagenic NQ was 2,3-dichloro-1,4-NQ, with mutagenicity of 18 induced revertants/nmol/plate for strain TA104 without S9 mix. Among the strains used, TA104, which is sensitive to oxidative mutagens, was the most sensitive to the NQs, and the second most sensitive strain was TA2637, which detects bulky DNA adducts. The relationship of mutagenic potency to the one-electron reduction potential with TA104 suggested that the higher redox potential NQs were more mutagenic than the lower redox potential NQs. Significant reduction of the mutagenicity of 1,4-naphthoquinone without S9 mix was observed in the presence of catalase. Enhancement of the mutagenic potential of the NQs by the pKM101 plasmid implicated in error-prone repair was also observed. The most cytotoxic NQ was 2,3-dichloro-5,8-dihydroxy-1,4-NQ, and the least cytotoxic NQ was beta-NQ-4-sulfonic acid potassium salt, a 700-fold range in potency. The cytotoxic effect of the NQs was largely dependent on the structures of their substituents.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

A total delivery system of genetically engineered drugs or cells for diseased vessels. Concept, materials, and fabricated prototype device.

The development of a percutaneous procedure using a catheterized system for diseased vessels has been increasingly in demand in conjunction with gene therapy using genetically engineered drugs (antisense) and cells. The authors' strategic concept realizes revascularization at narrowed, diseased sites and delivery of drugs or cells into the diseased tissues or targeted cells. An inflatable, drug-releasing double balloon is installed at the tip of a catheter. The outer balloon, fabricated with micropores (diameters of 20 and 30 mm) by an excimer laser ablation technique, releases a viscous solution containing a photoreactive polymer and drug or cells on inflation of the inner balloon. A photoresponsive water-soluble polymer, molecularly designed for its ability to achieve prolonged local residency of antisense DNA at the tissue level and enhanced transmembrane transport at the cellular level, is premixed with antisense oligonucleotide drug. On light irradiation, the nonionic polymer is reversibly converted to a positively charged polymer that can be complexed with highly negatively charged antisense DNA (c-myb), which may enhance the transmembrane delivery of antisense. On cessation of irradiation, the complex slowly dissociates to function intracellularly as an antisense drug, resulting in inhibition of cell proliferation. Thus, our integrated, dual-function balloon system may contribute to mechanical dilatation gene therapies at diseased vessels.

Angioplasty, Balloon, Coronary↗
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

Case report. Antenatal diagnosis of chorioangioma of the placenta: MR features.

We report a case of chorioangioma of the placenta, in which MR findings were useful in establishing the antenatal diagnosis. Polyhydramnios and a placental tumor that was 5 cm in size were visualized. The tumor had relatively high signal intensities on proton density imaging and T2-weighted imaging and showed partially high intensity signal rims on T1-weighted imaging, especially when using a breath-holding technique. Magnetic resonance imaging has an important role in detection and diagnosis of these lesions, particularly the larger tumors, so that appropriate steps can be taken to deal with the complications that may accompany this tumor.

Adult↗
PubMedDate not supplied

Localization of GTP-binding protein Go in the enteric nervous system in rat ileum.

The localization of a GTP-binding protein G(o) was examined immunohistochemically in rat ileum using antibodies against the alpha-subunit of G(o) (G(o) alpha). G(o) alpha-positive fibers clearly demonstrated the topography and structure of the enteric nervous system of the ileum. G(o) alpha was present only in the nervous system and was generally distributed both in synapse-rich and in nonsynaptic areas. The distribution of G(o) alpha in a nonsynaptic area suggests the possibility that G(o) may be involved not only in neurotransmission mechanisms but also in other functions.

Animals↗
PubMedDate not supplied

Myenteric and submucosal plexuses of the congenital aganglionosis rat (spotting lethal) as revealed by scanning electron microscopy.

A rat with a congenital aganglionosis develops a mega-small intestine and megacolon. This rat mutant has been used as an animal model for Hirschsprung's disease. The myenteric and submucosal plexuses of the rats were exposed by the trypsin-HCl digestion method and examined by scanning electron microscopy. In the control rats the myenteric and submucosal plexuses were present throughout the gut. However, in the mutant rats the myenteric plexus of duodenum was different from those of control rats; the mesh of plexuses varied both in size and shape. There were no myenteric or submucosal plexuses in the distal ileum or colon.

Animals↗
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↗