PubMed Health⌕ Search

Biomedical subjects

J Deguchi

Publications and source records attributed to J Deguchi.

At least 19 recordsLinked to original sources
PubMed2006

Reduced vascular reserve measured by stressed single photon emission computed tomography carries a high risk for stroke in patients with carotid stenosis.

AIM: A few studies have observed reduced vascular reserve measured by single photon emission computed tomography (SPECT) to be a risk factor for stroke in patients with carotid artery occlusion, but stenosis has been excluded from these former studies. This study has evaluated the prognosis of reduced vascular reserve in patients with stenosis, and the effect of carotid endarterectomy (CEA) on these patients. METHODS: Forty patients diagnosed as having >70% stenosis of the carotid artery at the University of Tokyo Hospital, between 2001 and 2004, underwent acetazolamide-stress SPECT test first. A resting SPECT study was performed on a different day from the stressed SPECT study. The patients were grouped as having reduced vascular reserve or normal vascular reserve from the SPECT results. Analysis of risk factors and the stroke-free curve analysis for reduced vascular reserve was performed. RESULTS: Of the 40 patients, 24 (60%) had reduced vascular reserve and 18 underwent CEA. The mean follow-up period was 21.5+/-15.5 months (mean+/-SD). Four strokes occurred during follow-up: in 1 patient with CEA and 3 without CEA. All stroke patients had reduced vascular reserve. The patients with reduced vascular reserve without any surgery had a significantly lower stroke-free rate compared with those with normal vascular reserve or reduced vascular reserve, but also receiving CEA. CONCLUSIONS: We propose performing SPECT tests in patients with severe carotid stenosis regardless of symptoms, and performing CEA on those with a reduction in vascular reserve.

Aged↗
PubMed2004

Spatiotemporal patterns of movement-related fields in stroke patients.

In this study, brain functions in stroke patients and normal subjects were analyzed by observing neuromagnetic fields during button pressing tasks. The measurements included force measurement, visual stimuli presentation and magnetoencephalography (MEG). A 122-channel whole-head MEG system (Neuromag 122) was used. A total of 18 subjects (11 post-stroke and 7 control subjects) participated in the study; adequate MEG data were obtained from 3 of the patients. Equivalent current dipoles for MRFs were estimated with the following parameters: goodness of fit (> 75%), confidence volume (< 6000 mm3), and the duration of dipole (> 10 msec). In addition to the single dipole analysis, Minimum Current Estimates were applied for source estimation since neural activities for stroke patients were observed at the motor cortex of the contralateral side as well as other areas of the brain. Contralateral motor cortex was activated for the normal subjects at 50 ms prior to the force onset, whereas ipsilateral motor cortex was activated for some stroke patients and patients' dipole moments differed not only in their locations but also in their latencies, ranging from -150 to 50 ms to the force onset. The results were in agreement with the findings by PET and fMRI studies; therefore, it was implied that the compensating motor functions were shifted to neighboring areas of the brain due to the recovering motor function after stroke.

Adult↗
PubMed2001

Successful management of tracheo-innominate artery fistula with endovascular stent graft repair.

Tracheo-innominate artery fistula is a highly lethal complication after tracheostomy. A 37-year-old man who had undergone a tracheostomy 14 years earlier because of dysphagia after brain surgery had a tracheo-innominate artery fistula with exsanguinating hemorrhage from his tracheostomy site. After temporary control of the bleeding, a stent graft was implanted in the innominate artery through the brachial artery. The patient recovered uneventfully and remained well 14 months after the procedure, with no sign of infection. Endovascular stent grafting may be the treatment of choice for patients with tracheo-innominate artery fistula.

Adult↗
PubMed2000

In vivo retention of endothelial cells adenovirally transduced with tissue-type plasminogen activator and seeded onto expanded polytetrafluoroethylene.

PURPOSE: Seeding a prosthetic graft with genetically engineered vascular endothelial cells (ECs) has the potential to enhance the graft's antithrombotic properties. However, it has been reported that ECs transduced with tissue-type plasminogen activator (tPA) have very low levels of retention on grafts, probably because of increased proteolytic activity. We examined the retention of human tPA (htPA)-transduced ECs after the cells were seeded onto expanded polytetrafluoroethylene (ePTFE) grafts and implanted into dogs. We also examined the function of secreted htPA in this model. METHODS AND RESULTS: Canine jugular venous ECs were transduced with adenoviral vectors encoding htPA (Adex1CAhtPA) and beta-galactosidase (Adex1CALacZ). There was a positive relationship between the percentage of X-gal ECs staining and the multiplicity of infection (MOI) of Adex1CALacZ. The level of htPA production in vitro increased with the increasing MOI of Adex1CAhtPA, but decreased gradually 4 days after infection. ECs coinfected with Adex1CAhtPA and Adex1CALacZ (htPAEC) or ECs infected with Adex1CALacZ alone (LacZEC) were seeded onto ePTFE grafts at densities equivalent to confluence to visualize retained ECs in an in vivo flow study. The grafts were implanted into canine carotid arteries and harvested after 5 hours of exposure to blood flow. The harvested grafts showed patchy defects in ECs, most of which were covered with mural thrombi. There was no significant difference in retention between htPAEC (29.3% +/- 8.7%) and LacZEC (19.5% +/- 3. 6%). There was a significant negative correlation between the in vivo EC retention on the grafts and the in vitro cellular passage level of ECs (P =.041; r = -.40). htPAEC produced 210.3 +/- 22.2 ng htPA antigen/10(6) cells per 6 hours in vitro and continued to secrete htPA on the harvested graft. CONCLUSIONS: We demonstrated that a large amount of functional htPA was produced by adenovirally modified canine ECs. The results of the in vivo study may suggest that overexpression of tPA has little effect on the short-term retention of early passage ECs seeded onto ePTFE grafts.

Adenoviridae↗
PubMed2000

Comparative analysis of the effects of gonadotropin-releasing hormone agonist on the proliferative activity, apoptosis, and steroidogenesis in cultured porcine granulosa cells at varying stages of follicular growth.

This study was conducted to analyze comparative effects of gonadropin-releasing hormone (GnRH) agonist on the proliferation, apoptosis, and differentiated function of cultured porcine granulosa cells from varying follicle stages. Comparative analyses of porcine granulosa cells from varying follicle stages to respond to GnRH agonist were performed in terms of proliferating cell nuclear antigen (PCNA) expression, occurrence of apoptosis, and 17beta-estradiol (E2) and progesterone (P) secretion. PCNA expression was examined by the avidin/biotin immunoperoxidase method with a monoclonal antibody to PCNA, and apoptosis was assessed by in situ DNA 3'-end labeling method and DNA fragmentation analysis. E2 and P were measured by radioimmunoassays. The PCNA positive rate of granulosa cells cultured in the presence of GnRH agonist (10(-9) M) was lower compared with that of cells cultured in the absence of GnRH agonist. However, the apoptosis positive rate was higher, and E2 and P secretion by cultured granulosa cells was lower in the presence of GnRH agonist (10(-9) M) compared with that in the absence of GnRH agonist. The inhibitory effect of GnRH agonist on PCNA positive rate of cultured cells was prominent in granulosa cells from small and medium but not from large follicles. By contrast, the inhibitory effect of GnRH agonist on E2 and P secretion by cultured cells was prominent in granulosa cells from large but not small and medium follicles. The stimulatory effect of GnRH agonist on apoptosis positive rate of cultured cells was, however, uniform regardless of the stages of follicular growth. These results demonstrate that GnRH agonist exerts diverse actions on granulosa cells over the course of follicular growth. One downregulates granulosa proliferation in immature follicles as well as steroidogenesis in mature follicles, and the other upregulates apoptosis of granulosa cells regardless of the stages of follicular growth.

Animals↗
PubMed2000

Intraventricular aneurysms--three case reports.

Three rare cases of purely intraventricular aneurysms are described, including a unique aneurysm in the fourth ventricle. A 30-year-old female, a 47-year-old male, and an 11-year-old girl presented with disturbance of consciousness due to massive intraventricular hemorrhage. Digital subtraction angiography revealed an idiopathic peripheral aneurysm in the fourth ventricle in the first patient, and aneurysms in the lateral ventricle associated with moyamoya disease in the latter two patients. The former two aneurysms were treated surgically and histologically confirmed to be pseudoaneurysms. The latter aneurysm disappeared spontaneously within 2 months after onset. The aneurysm in the lateral ventricle was resected via a parietal corticotomy with stereotactic insertion of an 8-Fr silicone tube to guide the approach route. This method was very useful because computerized neuronavigation was not available. The aneurysm in the fourth ventricle was resected via a midline suboccipital approach with C-1 laminectomy. Conservative treatment is usually recommended initially for patients with intraventricular aneurysm because spontaneous cure often occurs. We recommend direct surgery if the size of the aneurysm remains unchanged, because the risk of surgery has decreased recently owing to new techniques for neuronavigation.

Adult↗
PubMed2000

Patency after revision surgery for failing infrainguinal vein grafts.

BACKGROUND: Although the results of bypass surgery on arteries in the lower extremities have been greatly improved during the last decades, there are still a significant number of primary failures. In order to investigate the reasons for the failure of autogenous vein grafts after infrainguinal arterial bypass surgery and to ascertain the results of revision operations on the failing grafts, we conducted a clinical study. METHODS: Retrospective study on 104 patients who underwent infrainguinal arterial revascularisation with autogenous veins. RESULTS: One hundred and twenty-six bypasses were constructed in 121 limbs. Seventy-nine of these were for claudication and 47 for threatened limbs (rest pain or ischaemic tissue loss). Five-year primary and secondary patency rates were 69.7% and 84.9% respectively. Spliced or suture-repaired grafts had a poor outcome; five out of seven eventually becoming thrombosed. On the other hand, revision operations for failing but not yet thrombosed grafts produced good results; the five-year primary patency rate after these operations was 76.0%, whereas after single-segment primary grafting it was 72.1%. CONCLUSIONS: These results stress the importance of vigilant follow-up and active intervention for failing grafts. Poor outcome with injured vein grafts emphasizes the importance of meticulous vein harvesting.

Adult↗
PubMed1999

Angiotensin II stimulates platelet-derived growth factor-B chain expression in newborn rat vascular smooth muscle cells and neointimal cells through Ras, extracellular signal-regulated protein kinase, and c-Jun N-terminal protein kinase mechanisms.

Platelet-derived growth factors (PDGFs) have been implicated in the pathogenesis of vascular proliferative disorders. Vascular smooth muscle cells (VSMCs) are one of the cell types that produce PDGF-B chain in proliferative lesions, although the mechanism of regulation of PDGF-B chain production in these cells is not well understood. In the present study, we demonstrate that angiotensin II (Ang II), which is also implicated in vascular stenosis after angioplasty and atherosclerosis, markedly stimulates PDGF-B chain mRNA expression in cultured newborn rat medial VSMCs and neointimal VSMCs via an AT(1), but not in adult rat VSMCs. In newborn rat VSMCs, Ang II activates extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal protein kinase (JNK), and p38 mitogen-activated protein kinase. The mitogen-activated protein/ERK (MEK) inhibitor PD98059, but not the p38 inhibitor SB203580, abrogates Ang II-induced PDGF-B mRNA expression. Transient transfection analysis using a PDGF-B promoter-luciferase gene reporter construct reveals that Ang II induces transcriptional activation of PDGF-B chain gene, which is abolished by the expression of a dominant negative form of either ERK or JNK, but not of p38. The expression of a dominant negative form of Ras abolishes the stimulatory effects of Ang II on ERK activity and PDGF-B mRNA expression. In adult rat VSMCs, Ang II activates ERK and JNK, but weakly induces Egr-1, a transcription factor implicated in PDGF-B chain gene expression, compared with newborn VSMCs. These data indicate that Ang II activates PDGF-B chain gene expression in VSMCs through mechanisms involving Ras-ERK and JNK.

Aging↗
PubMed1999

Surgery for descending thoracic aortic anastomotic aneurysms with a temporary external bypass method.

The surgical treatment of descending thoracic aortic anastomotic aneurysms is technically challenging. The purpose of this study was to evaluate the use of a temporary external bypass method as an intraoperative measure in the surgical treatment of anastomotic aneurysms of the descending thoracic aorta. An analysis of five consecutive patients who had undergone surgery for a collective seven descending thoracic aortic anastomotic aneurysms in our university hospital over a period of 14 years was conducted. A temporary bypass technique was used as an intraoperative measure in all the operations, four of which were performed with a right axillary to left external iliac artery bypass, while other sites were used in the remaining three. Systemic heparinization was able to be avoided in six operations and was markedly reduced in the remaining one. Although the major postoperative complication was coagulated hemothorax after six procedures, all patients recovered well and are still alive after a mean follow-up period of 8.2+/-1.5 (SEM) years. The results of this analysis led us to conclude that our temporary bypass method for treating descending thoracic aortic anastomotic aneurysm prevented the risks of anticoagulant administration for circulatory support, which contributed to the success of the operation. This method can be used as adjunct treatment for anastomotic aneurysms in the descending thoracic aorta.

Adult↗
PubMed1999

Diamox((R)) challenge test to decide indications for cerebrospinal fluid shunting in normal pressure hydrocephalus.

OBJECTIVE: The indications for cerebrospinal fluid (CSF) shunting in patients with normal pressure hydrocephalus (NPH) have not been established. Establishment of clear-cut indications for this procedure is essential to ensure cost-effective, and safe treatment. We report the usefulness of the Diamox((R)) challenge test in evaluating indications for CSF shunting in patients with NPH. METHODS: Pre- and post-operative responses in cerebral blood flow (CBF) and intracranial pressure (ICP) to intravenous administration of Diamox((R)) 1000mg (Diamox((R)) administration) were analysed in 41 patients with NPH who were treated by ventriculoperitoneal (VP) shunt with a programmable valve and an on-off valve. RESULTS: The preoperative response of ICP to Diamox((R)) administration was more than 10 mmHg in most patients in whom the shunt was effective (shunt effective group), however, it was less than 10 mmHg in most patients in whom the shunt was ineffective (shunt non-effective group). Furthermore, the postoperative response of ICP to Diamox((R)) administration decreased to less than 10 mmHg in most patients in the shunt effective group. The increases in CBF in response to Diamox((R)) administration were similar in the two groups both before and after placement of the VP shunt. CONCLUSION: Patients in whom ICP increased by more than 10 mmHg in response to Diamox((R)) administration were regarded to have poor CSF circulation and to thus be candidates for CSF shunting. The Diamox((R)) challenge test is a simple, safe procedure, useful in evaluating the response to treatment.

Acetazolamide↗
PubMed1999

Inhibitory effects of trapidil on PDGF signaling in balloon-injured rat carotid artery.

Trapidil, which was originally developed as an anti-platelet agent, is among the few agents thus far proven to be clinically effective in preventing restenosis after percutaneous coronary interventions. Trapidil was previously shown to inhibit platelet-derived growth factor (PDGF)-induced cellular responses in vitro in cultured cells. However, its mechanism of action is poorly understood. In this study, we investigated by using a rat carotid balloon-injury model whether and how trapidil inhibited the in vivo action of PDGF, which is regarded as a most important growth factor implicated in proliferation and migration of vascular smooth muscle cells. The combination of both oral and topical administration of trapidil reduced the intimal lesion size by more than 70% and nearly completely suppressed injury-induced increases in phosphotyrosine content of PDGF alpha- and beta- receptors of carotid artery. Moreover, trapidil was found to decrease mRNA levels of PDGF alpha- and beta- receptors strongly and of PDGF A- and B- chains moderately in injured arteries. These results indicate that trapidil potently suppresses the action of PDGF with inhibition of neointima formation in injured artery, which is mediated at least in part through decreasing the expression of both PDGF ligands and their receptors.

Angioplasty, Balloon↗
PubMed1999

Targeting endogenous platelet-derived growth factor B-chain by adenovirus-mediated gene transfer potently inhibits in vivo smooth muscle proliferation after arterial injury.

Platelet-derived growth factor (PDGF), especially its B chain, has been implicated in the pathogenesis of vascular proliferative disorders such as atherosclerosis and restenosis after angioplasty. We constructed a replication-deficient recombinant adenovirus containing the gene encoding the extracellular region of PDGF beta-receptor (PDGFXR) that binds PDGF-B chain and acts as its antagonist. The administration into balloon-injured rat carotid arteries of an adenovirus containing the Escherichia coli lacZ gene as a marker gene at 5 days after injury markedly facilitated efficacy of gene transfer, as compared with its administration immediately after injury. Adenovirus-mediated gene transfer of PDGFXR into injured arteries performed at 5 days resulted in a more than 50% reduction in the neointimal area of injured arteries at 14 days. In contrast, the administration of control adenoviruses containing lacZ gene or containing no foreign gene was without suppressive effects on neointima formation. The inhibition of neointima formation by the expression of PDGFXR was accompanied by a reduction in bromodeoxyuridine-labeled cells and nearly complete inhibition of tyrosine phosphorylation of both alpha- and beta-receptors for PDGF, but not of epidermal growth factor receptor, in injured arteries. This is the first report to indicate the usefulness of targeting a growth factor by expressing an extracellular binding region of a receptor using an adenovirus for the treatment of vascular proliferative disorders, and provide direct evidence that PDGF-B chain plays an essential role in neointimal formation.

Adenoviridae↗
PubMed1999

[Microsurgical results of paraclinoid aneurysms of the internal carotid artery: microsurgery versus intravascular surgery].

Since paraclinoid aneurysms exhibit considerable variations in the surrounding skull base structures, some skill and experience are considered essential for their microsurgical treatment. On the other hand, intravascular coil embolization would be free from these extravascular factors. Fifty-two aneurysms in 48 patients were treated microsurgically. They were divided into an early series treated before 1995 and a late series treated after 1996. Three aneurysms in 3 patients were treated by intravascular surgery. Preoperative neuroimages, topographic anatomy and surgical results were compared retrospectively. The results in the microsurgical late series were better than those in the early series. While 89% of the patients exhibited excellent results with two patients left with partial visual field defect (7%) and one death (3%) in the early series, the rates in the late series were 95%, 5% and 0%, respectively. Complications and failure in neck clipping were considered to be due to such topography as, 1) C3 aneurysms extending into the anterior clinoid process, 2) multiple aneurysms, 3) ophthalmic artery originating near the dome, 4) atheroma or calcification at the neck, 5) marked medical shift of C2 segment, and 6) tight adhesion of the dural ring to the dome. Coil embolization was successful in two aneurysms, while it was given up in one. We currently propose that intravascular surgery is indicated for cases 1), 4), 5) and 6), and microsurgery would be more advantageous for cases where the neck is broad and where the topography concerning aneurysmal multiplicity or the branching site of the ophthalmic artery is not fully understood by preoperative imaging.

Aneurysm↗
PubMed1998

Intranuclear iron deposition in hepatocytes and renal tubular cells in mice treated with ferric nitrilotriacetate.

Cytoplasmic and intranuclear iron depositions were observed in the livers and kidneys of male and female ddY mice treated for 4-12 weeks with ferric nitrilotriacetate (Fe-NTA), a known renal carcinogen that acts through the production of free radicals. The intranuclear iron deposition consisted of a spherical aggregation of ferritin particles of approximately 10 nm diameter, as revealed by immunohistochemical staining and electron microscopy. Although the incidence of renal tumours was greater in the males than in the females, the incidence of iron depositions did not differ with gender. The most abundant intranuclear iron depositions were observed in the animals treated with Fe-NTA for the longest duration (12 weeks). These findings suggest that the intranuclear production and propagation of free radical reactions are prevented by the trapping of iron in a chemically inert iron form of ferritin.

Animals↗
PubMed1998

Anastomotic aneurysms after surgical treatment of Takayasu's arteritis: a 40-year experience.

PURPOSE: To evaluate the clinical characteristics of anastomotic aneurysms that develop in surgically treated patients with Takayasu's arteritis. METHODS: Among 103 patients with Takayasu's arteritis treated surgically over 40 years, 91 patients with 259 anastomoses (allowing for exclusion of 12 operative deaths) participated in follow-up study from 1 month to 37.3 years with a mean value +/- SEM of 17.3 +/- 1.1 years with a follow-up completion rate of 93% at 30 years. The clinical characteristics of anastomotic aneurysms were clarified, and the influences of several factors (sites of anastomoses, occlusive or aneurysmal disease, suture material, preoperative systemic inflammation, and administration of corticosteroids) on formation of anastomotic aneurysms were analyzed by means of life-table method and Cox regression analysis. RESULTS: Twenty-two uninfected anastomotic aneurysms were found among 14 patients (22 of 259 anastomoses, 8.5%). The interval between the previous operation and diagnosis varied from 1.6 to 30 years with a mean value +/- SEM of 9.8 +/- 1.8 years. The cumulative incidence of anastomotic aneurysm at 20 years was 12.0%. Systemic inflammation or steroid administration had little influence on formation of anastomotic aneurysm. Instead, anastomotic aneurysm tended to occur after operations for aneurysmal lesions. CONCLUSIONS: Anastomotic aneurysm can occur anytime after operations for Takayasu's arteritis. The development of anastomotic aneurysm is not influenced by any factor specific to this disease except the presence of an aneurysmal lesion.

Adolescent↗
PubMed1998

Tyrosine phosphorylation of platelet derived growth factor beta receptors in coronary artery lesions: implications for vascular remodelling after directional coronary atherectomy and unstable angina pectoris.

BACKGROUND: Growth factors such as platelet derived growth factor (PDGF) have been postulated to be important mediators of neointimal proliferation observed in atherosclerotic plaques and restenotic lesions following coronary interventions. Binding of PDGF to its receptor results in intrinsic receptor tyrosine kinase activation and subsequent cellular migration, proliferation, and vascular contraction. AIMS: To investigate whether the concentration of PDGF beta receptor tyrosine phosphorylation obtained from directional coronary atherectomy (DCA) samples correlate with atherosclerotic plaque burden, the ability of diseased vessels to remodel, coronary risk factors, and clinical events. METHODS: DCA samples from 59 patients and 15 non-atherosclerotic left internal thoracic arteries (LITA) were analysed for PDGF beta receptor tyrosine phosphorylation content by receptor immunoprecipitation and antiphosphotyrosine western blot. The amount of PDGF beta receptor phosphorylation was analysed in relation to angiographic follow up data and clinical variables. RESULTS: PDGF beta receptor tyrosine phosphorylation in the 59 DCA samples was greater than in the 15 non-atherosclerotic LITA (mean (SD) 0.84 (0.67) v 0.17 (0.08) over a control standard, p < 0.0001). As evaluated by stepwise regression analysis, incorporation of both PDGF beta receptor tyrosine phosphorylation and immediate gain correlated strongly (adjusted r2 = 0.579) with late loss, although PDGF beta receptor tyramine phosphorylation alone correlated poorly with late loss. Multivariate regression analysis of coronary risk factors and clinical events revealed unstable angina as the most significant correlate of PDGF beta receptor tyrosine phosphorylation (F value 20.009, p < 0.0001). CONCLUSIONS: PDGF beta receptor tyrosine phosphorylation in atherosclerotic lesions is increased compared with non-atherosclerotic arterial tissues. The association of PDGF beta receptor tyrosine phosphorylation with immediate gain strongly correlates with vascular remodelling. PDGF beta receptor tyrosine phosphorylation correlates with unstable angina pectoris.

Angina, Unstable↗
PubMed1998

Serum deprivation-induced apoptosis in cultured porcine granulosa cells is characterized by increased expression of p53 protein, Fas antigen and Fas ligand and by decreased expression of PCNA.

Although serum deprivation induces apoptosis in several cell lines, biochemical characterization of the apoptosis in primary granulosa cells (GCs) induced by serum deprivation has rarely been reported. In the present study, GCs from small follicles of porcine ovaries were precultured under a serum-containing condition for seven days, then stepped down to a serum-free condition and cultured for the subsequent two days. GCs were subjected to DNA fragmentation and immunoblot analyses. Data indicated that serum deprivation induced GC apoptosis characterized by DNA laddering, which was associated with decreased expression of proliferating cell nuclear antigen (PCNA) and increased expression of p53 protein, Fas antigen and Fas ligand. Serum deprivation also resulted in an increase in a 115 kDa protein expression despite no detectable expression of a 66 kDa c-myc protein. This suggests that serum removal from primary GCs may activate multiple apoptotic pathways such as a p53-associated pathway and a Fas-Fas ligand pathway.

Animals↗