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Biomedical subjects

M Ishida

Publications and source records attributed to M Ishida.

At least 37 records · Page 2Linked to original sources
PubMed2001

Application of ion beam techniques for preparation of metal ion-implanted TiO2 thin film photocatalyst available under visible light irradiation: metal ion-implantation and ionized cluster beam method.

Transparent TiO2 thin film photocatalysts have been prepared on silica glass plate by an Ionized Cluster Beam (ICB) method. In order to improve the electronic properties of these photocatalysts, transition metal ions (V+, Cr+, Mn+, Fe+) were implanted into the TiO2 thin films at high energy acceleration using an advanced metal ion-implantation technique. The combination of these ion beam techniques can allow us to prepare the TiO2 thin film photocatalysts which can work effectively under visible light (lambda>450 nm) and/or solar light irradiation. The investigation using XAFS and ab initio molecular calculation suggests that the substitution of octahedrally coordinated Ti ions in TiO2 lattice with implanted metal ions is important to modify TiO2 to be able to adsorb visible light and operate under visible light irradiation.

Journal Article↗
PubMed2001

Immunohistochemical phenotypic alterations of rabbit autologous vein grafts implanted under arterial circulation with or without poor distal runoff-implications of vein graft remodeling.

Although intimal hyperplasia is a major cause limiting the long-term patency of the vein grafts, its precise mechanisms, including the effect of poor runoff, has not yet been well characterized. We thus designed the present study to try to determine the effect of poor runoff arterial flow to the phenotypic alterations of the graft wall by immnohistochemistry using anti-intermediate filaments (alpha-SM actin, desmin, and vimentin) and anti-myosin heavy chain (SM1, SM2, and SMemb) specific antibodies. Vein grafts implanted under the poor runoff hind limb of rabbits showed enhanced intimal hyperplasia, however, no apparent difference in the cytoskeleton expression, including intermediate filaments and MHC, between two groups until 4 weeks. Interestingly, six of eight vein grafts at 2 weeks after implantation in both groups showed the accumulations of perivascular fibroblast-like phenotype (negative for SM1, alpha-SM actin, and desmin) in some parts of the outer neointima, whereas the inner neointima at 2 weeks and the whole neointima at 4 weeks were mainly occupied by a smooth muscle phenotype (positive for these three). Although the cellular origin of these cells is still unknown, these results suggest that the migration of non-muscle mesenchymal cells is involved in the neointima and thus may provide a clue for better understanding vein graft remodeling.

Anastomosis, Surgical↗
PubMed2001

Endoscopic extirpation of benign breast tumors using an extramammary approach.

BACKGROUND: Skin incision has been made directly in the breast for treatment of benign breast tumor in spite of the young age of the patient population. METHODS: Small incisions (12 mm, 5 mm, and 2 mm) were made in the extramammary line, and the benign tumors (diagnosed by imaging and aspiration needle cytology) were endoscopically extirpated. RESULTS: The mean age of 36 patients was 27.6 years, and the mean mass size was 3.6 cm (7 masses at maximum). The average operation time per mass was 2.6 hours in the first 18 operations and 1.4 hours in the latter 19 operations. Overall blood loss was 19 mL. Postoperative complications were seen in 2 patients: an extended subcutaneous emphysema due to excessive CO2 gas inflation and a mild burn, both of which were reversible. All patients were extremely satisfied with the cosmetic results of the procedure. CONCLUSIONS: Endoscopic removal by the extramammary approach is the best option for benign breast tumors considering the patient's age and the excellent cosmetic results.

Adolescent↗
PubMed2001

Non-Hodgkin's malignant lymphoma of the sinonasal tract--treatment outcome for 53 patients according to REAL classification.

OBJECTIVE: Although the Working Formulation is commonly used to classify NHL in Japan, it has been recognized as imperfect for primary extranodal lymphoma, especially for patients with sinonasal disease because of their histological characteristics. The present study investigated the clinical characteristics and the prognosis of sinonasal lymphomas according to REAL classification. METHODS: Fifty-three patients with non-Hodgkin's malignant lymphoma (NHL) of the sinonasal tract were treated between 1981 and 1997. The age at clinical presentation was from 10 to 84 years (mean, 52.4 years). According to the Ann Arbor system, there were 30 patients with Stage IE, 13 with Stage IIE, 4 with Stage IIIE, and 6 with Stage IVE lymphomas. Twenty-two patients (41.5%) had B symptoms. The primary sites were the nasal cavity (67.8%), maxillary sinus (20.8%), ethmoidal sinus (9.4%), and frontal sinus (1.9%). The survival data was calculated by Kaplan-Meier method. Statistical analysis was performed with a generalized Wilcoxon method. RESULTS: All of the lymphomas showed a diffuse growth pattern. Based on the origin of the tumor cells, the authors classified NHL of the sinonasal tract into five groups with the REAL classification of Japan: diffuse large B-cell lymphoma (22.6%), peripheral T-cell lymphomas (15.1%), angiocentric lymphoma (35.9%), other lymphomas and unclassified types. Of 53 patients, 39 (73.6%) received chemotherapy and radiotherapy, eight patients received chemotherapy alone, and four patients received radiotherapy alone. The cumulative 5-year survival rates were 28.5% for all of the types, 55.0% for diffuse large B-cell lymphoma, 33.3% for peripheral T-cell lymphoma, and 19.7% for angiocentric lymphoma. Results suggest that conventional combined treatment (CHOP chemotherapy+radiotherapy) is ineffective for NHL of the sinonasal tract, and especially so for NHL in the nasal cavity, NHL with tumor cells with positive T-cell markers, NHL further than Stage IIE and NHL with B symptoms. CONCLUSION: (1) In light of this ineffectiveness, new therapies must be developed to improve patient outcome instead of the conventional combined treatment; (2) REAL classification is clear and useful for sinonasal lymphomas in Japan.

Adolescent↗
PubMed2001

Treatment of chronic aortic dissection by transluminal endovascular stent-graft placement: preliminary results.

PURPOSE: To investigate efficacy of stent-graft repair for the treatment of patients with chronic aortic dissection. MATERIALS AND METHODS: Fifteen patients with chronic aortic dissection were treated with endovascular stent-grafts. Entry tears were located in the descending thoracic aorta in all patients. The mean maximum diameter of the descending thoracic aorta was 47 mm +/- 8. The mean diameter of the true lumen at the same level was 20 mm +/- 5. The mean interval between diagnosis and stent-graft procedure was 32 months +/- 91. Stent-grafts were fabricated from expanded polytetrafluoroethylene and Z-stents. RESULTS: Stent-grafts were placed successfully in all patients. Two stent-grafts were required in one patient. Entry closure and thrombosis of the false lumen of the descending thoracic aorta were also achieved in all patients. No procedure-related complications were observed except for postimplantation syndrome, including fever and leukocytosis. The diameter of the true lumen was significantly increased (mean, 31 mm +/- 6) at the level of the descending thoracic aorta (P <.01) and the diameter of the aorta was significantly decreased (mean, 44 mm +/- 8) at the same level (P <.01). There were no deaths and no instances of aortic rupture during the subsequent average follow-up period of 24 months. Secondary stent-graft procedures were required to treat the abdominal component of dissection during follow-up in one patient. CONCLUSIONS: Stent-graft repair of chronic aortic dissection is a safe and effective method and may be an alternative to surgical graft replacement in selected patients. However, further evaluation is mandatory before this method is widely employed.

Adult↗
PubMed2001

Effects of a vitamin E-modified dialysis membrane on neutrophil superoxide anion radical production.

Activation of neutrophil by the dialysis membrane and peroxidative stress plays an important role on the pathogenesis of complications in hemodialysis (HD) patients. Vitamin E is one of the potent scavengers for reactive oxygen species. Recent studies suggest that a vitamin E-modified multilayer membrane (Excebrane, CL-EE dialyzer) has an inhibitory effect on serum lipids peroxidation in HD patients. To determine the effect of CL-EE on biocompatibility in clinical use, we measured the superoxide anion radical producing ability (SOPA) of polymorphonuclear leukocytes (PMNLs), the plasma hydroxyl radical producing ability (OHPA) and superoxide anion radical scavenging activity (SSA). SOPA was measured after stimulation of PMNLs with phorbol myristate acetate using electron paramagnetic resonance (EPR) method. Plasma OHPA and SSA were also determined using the EPR method. In addition, the plasma concentrations of malondialdehyde (MDA) and oxidized low-density lipoprotein (LDL), as the parameters for lipid peroxidation, were measured. SOPA was decreased in patients who used conventional filter membrane compared with healthy controls. In the patients using the CL-EE membrane, SOPA gradually increased and reached control levels after six months. However, no significant increase was observed in patients who used a conventional filter membrane. OHPA of HD patients was significantly decreased compared with controls. In the CL-EE membrane patient group, OHPA was significantly increased at six months. SSA was significantly higher in the conventional filter membrane group than controls. In the CL-EE membrane patient group, SSA gradually decreased at six months. Plasma MDA and oxidized LDL levels were significantly higher in HD patients compared with controls. These values slowly decreased, and significant differences were found after nine months of using the CL-EE membrane. These findings suggest that activation of PMNLs and plasma OHPA and SSA in HD patients is attenuated by antioxidant effects of the CL-EE.

Adult↗
PubMed2001

Aneurysmal degeneration of the aorta after stent-graft repair of acute aortic dissection.

PURPOSE: Stent-graft repair of acute aortic dissection has only recently begun, and the true efficacy and safety of this technique have not yet been clarified. In this report, we describe a significant, previously unreported complication following stent-graft repair of acute aortic dissection. MATERIALS AND METHODS: Fourteen patients with acute aortic dissection underwent stent-graft repair. All of the entry tears were located in the descending thoracic aorta. Five patients had type A aortic dissection, and nine patients had type B aortic dissection. The entry tears were closed with stent-grafts, which were fabricated from expanded polytetrafluoroethylene and Z-stents. RESULTS: Stent-graft placement was successfully performed without any complications in all patients. Entry closure was achieved in 13 (93%) of 14 patients. The mean follow-up period was 18 months (range, 9 days to 36 months). During this period, four patients had saccular aneurysms in the proximal descending thoracic aorta. A saccular aneurysm was noted during a mean follow-up period of 63 days (range, 38-99 days). Two of these patients were treated with stent-grafts. Conventional surgical repair is planned in one patient. The other patient is being treated with conservative management. CONCLUSIONS: Stent-graft repair is a technically feasible and effective method for the treatment of acute aortic dissection in selected patients. However, careful follow-up is mandatory to check for the development of saccular aneurysms.

Aged↗
PubMed2001

Transluminal placement of endovascular stent-grafts for the treatment of type A aortic dissection with an entry tear in the descending thoracic aorta.

PURPOSE: The current therapy for type A aortic dissection is ascending aortic replacement. Operative mortality and morbidity rates have been markedly improved because of recent advances in surgical techniques and anesthesiology. However, type A aortic dissection with an entry tear in the descending thoracic aorta is still a surgical challenge because of the need for extensive aortic replacement. METHODS: Ten patients with type A aortic dissection were treated with endovascular stent-grafts. The false lumen of the ascending aorta was patent in five patients, and it was thrombosed in the other five patients. The entry tears were located in the descending thoracic aorta in all cases. Seven patients had acute dissection, and three patients had subacute dissection. Four patients had pericardial effusion. Stent-grafts were fabricated from expanded polytetrafluoroethylene and Z-stents. RESULTS: Entry closure was achieved in all patients. Complete thrombosis of the false lumen of the ascending aorta was observed after stent-grafting in all patients. A second stent-graft was required in two patients to obtain complete thrombosis of the false lumen of the descending thoracic aorta. No procedure-related complications were observed, with the exception of a minor stroke in one patient. During a mean follow-up period of 20 months, no aortic rupture or aneurysm formation was noted in either the ascending or descending thoracic aorta, and all patients were alive and doing well. The abdominal aortic aneurysm enlarged after stent-grafting in one patient, and this was treated by closing the fenestrations of the abdominal aorta with stent-grafts. CONCLUSION: Stent-graft repair of aortic dissection with an entry tear in the descending thoracic aorta is a safe and effective method and may be an alternative to surgical graft replacement in highly selected patients.

Adult↗
PubMed2001

The -141C Ins/Del polymorphism in the dopamine D2 receptor gene promoter region is associated with anxiolytic and antidepressive effects during treatment with dopamine antagonists in schizophrenic patients.

Previous studies have demonstrated a lower density of dopamine D2 receptor (DRD2) in subjects without Del alleles of the -141C Ins/Del polymorphism in DRD2 gene promoter region than in those with one or two Del alleles. The present study aimed to examine whether the -141C Ins/Del DRD2 promoter polymorphism is related to therapeutic response to selective DRD2 antagonists in the treatment of schizophrenia. Subjects consisted of 49 acutely exacerbated schizophrenic inpatients treated with bromperidol (30 cases, mean dose +/- SD: 11.4 +/- 4.8 mg/day) or nemonapride (19 cases, 18 mg/day). Clinical symptoms were evaluated by the Brief Psychiatric Rating Scale (BPRS) before and 3 weeks after the treatment. The -141C Ins/Del DRD2 genotypes, the Ins and Del alleles, were determined by a polymerase chain reaction method. Thirty-five patients were homozygous for the Ins allele and 14 were heterozygous for the Del and Ins alleles. The patients without Del allele showed a higher percentage of improvement in anxiety-depression symptoms than those with Del allele (58.5 +/- 44.5% versus 24.1 +/- 48.2%) after 3 weeks of treatment while percentage improvement in total BPRS or other subgrouped symptoms (positive, negative, excitement and cognitive symptoms) was similar between the two genotype groups. The present results suggest that the -141C Ins/Del DRD2 polymorphism is associated with anxiolytic and antidepressive effects of neuroleptic treatment in schizophrenic patients.

Adult↗
PubMed2001

Apoptosis is not increased in myocardium overexpressing type 2 angiotensin II receptor in transgenic mice.

To determine whether angiotensin type 2 (AT(2)) receptor stimulation induces apoptosis in cardiomyocytes in vivo, we developed transgenic mice overexpressing the AT(2) receptor in a cardiac-specific manner, using the alpha-myosin heavy-chain promoter. Ten- to 12-week-old male homozygous transgenic mice (n=44) and wild-type mice (n=44) were used. Both transgenic and wild-type mice were given either saline (control), a subpressor dose of angiotensin II (100 ng. kg(-1). min(-1)), a pressor dose of angiotensin II (1000 ng. kg(-1). min(-1)) for 14 days, a pressor dose of angiotensin II for 28 days to investigate the effects of stimulation on both angiotensin type 1 (AT(1)) and AT(2) receptors, the AT(1) antagonist L158809 alone, or a combination of angiotensin II (1000 ng. kg(-1). min(-1)) and L158809 for 14 days to investigate the effects of selective AT(2) receptor stimulation. Apoptosis was analyzed in paraffin-embedded ventricular sections by the terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling (TUNEL) technique. In both transgenic and wild-type mice, administration of a subpressor dose of angiotensin II, L158809, or a combination of angiotensin II and L158809 did not significantly affect the tail-cuff blood pressure or heart-to-body weight ratio, whereas administration of a pressor dose of angiotensin II for 14 or 28 days significantly increased blood pressure and the heart-to-body weight ratio. However, there was no statistical difference between the effects of angiotensin II in transgenic and wild-type mice. The number of TUNEL-positive nuclei was approximately 0 to 10 per 100 000 cardiomyocytes, with no difference between transgenic and wild-type mice, regardless of saline infusion or any stimulation. In infarcted canine myocardial tissue sections for positive control, the number of TUNEL-positive nuclei was increased by 13.8 to 19.1 times compared with those in the noninfarcted myocardium. In conclusion, angiotensin II infusion for a period of 28 days failed to induce cardiomyocyte apoptosis regardless of the presence or absence of cardiac AT(2) receptor overexpression. It is unlikely that in mice the AT(2) receptor is a strong signal to induce cardiomyocyte apoptosis in vivo.

Angiotensin II↗
PubMed2001

Response of MCF-7 human breast cancer cells to some binary mixtures of oestrogenic compounds in-vitro.

The effects of simultaneous administration of some binary mixtures of seven natural and synthetic oestrogenic substances (17beta-estradiol, estrone, bisphenol A, butylbenzyl phthalate, endosulfan, methoxychlor and pentachlorophenol) on the cellular proliferation of human breast cancer MCF-7 cells in-vitro (a modified E-screen assay) have been measured. To assess the presence or absence of interactions of the two agents, the data were analysed on the basis of a graphical method in which the types and extents of interactions were described by response-surface diagrams. Of the nine combinations of the agents examined, synergistic interaction was evident for the combination of 17beta-estradiol and bisphenol A, whereas the remaining eight combinations were weakly synergistic, additive and/or weakly antagonistic in the dose-range tested.

Benzhydryl Compounds↗
PubMed2001

Difference between horizontal and vertical optokinetic nystagmus in cats at upright position.

UNLABELLED: The slow-phase velocity (SPV) of optokinetic nystagmus (OKN) and optokinetic after nystagmus (OKAN) in response to a velocity step of surround rotation in the horizontal direction is composed of the rapid and slow components in the cat: a rapid rise, a slow rise to a steady state, a rapid fall, and a slow decline to 0 deg/s. The rapid and slow components are attributed to the direct pathway and velocity storage neuronal mechanisms, respectively. The difference between horizontal and vertical OKN has been reported in the monkey at the upright position, but the slow and rapid components have not been distinguished. The present study compared horizontal OKN-OKAN with vertical OKN-OKAN in the cat at the upright position, distinguishing the rapid and slow components. Constant velocity rotation of a random dot pattern at a velocity of 5 to 160 deg/s was used for optokinetic stimulation. THE RESULTS: First, the amplitude of the rapid rise was relatively small in all SPV directions and all stimulus velocities investigated, with a slight upward-SPV preference to the downward-SPV (maximum 6.4, 6.0, and 3.4 deg/s in horizontal, upward, and downward SPV directions, respectively). Second, the steady state velocity was large during horizontal OKN (maximum 69.0 deg/s), small during upward-SPV OKN (12.9 deg/s), and missing (SPV is negligibly small and irregular) during downward-SPV OKN, indicating a large directional difference of OKN. Third, the acceleration of the slow rise decreased with the stimulus velocity at higher stimulus velocities >20 deg/s during both horizontal and upward-SPV OKN, suggesting strong nonlinearity in the velocity charge system. Fourth, the decay time course of the OKAN was described by the time constant of the exponential function, and the time constant was longer during horizontal (mean, 8.3 s at a stimulus velocity of 20 deg/s) than during upward-SPV (5.4 s) OKAN, suggesting that the velocity discharge system is relatively linear compared with the velocity charge system. It is concluded that horizontal OKN-OKAN is much larger than vertical OKN-OKAN in the cat at the upright position, and this directional difference is caused mainly by the directional difference in the velocity storage mechanism, but not in the direct pathway mechanism.

Animals↗
PubMed2001

Effect of injection volume on the pharmacokinetics of oil particles and incorporated menatetrenone after intravenous injection as O/W lipid emulsions in rats.

Oil-in-water lipid emulsions are promising drug carriers for lipophilic drugs, however, the pharmacokinetics after entering the circulation should be clarified at clinical injection volume in order to utilize them in a clinical situation. In the present study, the standard lipid emulsions, consisting of soybean oil, egg yolk phosphatides and menatetrenone with diameters of about 150 nm, were prepared using a microfluidizer system. The pharmacokinetics of menatetrenone and the oil particles after intravenous injection as standard lipid emulsions at various injection volumes, from the clinical injection volume (0.1 ml/kg) to the experimental injection volume (3.0 ml/kg), were examined in rats. The plasma concentrations of menatetrenone and the oil particles were similar after administration, showing that menatetrenone was not released even after entering the circulation. Menatetrenone was delivered to the liver and spleen at the clinical injection volume, and more menatetrenone was delivered to the liver at clinical injection volume compared with the experimental volume. Moreover, additional information on injection volume-dependency was also obtained from these findings. These results at various injection volumes suggested that the standard lipid emulsions can be utilized as a useful drug delivery system at the clinical injection volume, especially for liver and spleen targeting.

Animals↗
PubMed2001

Establishment of a simple method for measurement of chronic blood flow in uterine artery of pregnant cows.

Blood flow to the gravid uterine horn of seven multiparous Holstein cows (mean +/- SD, BW = 625.5 +/- 82.4 kg; age = 4.7 +/- 1.7 yr; parity = 2.9 +/- 1.1 yr) was measured from d 225 of gestation to parturition using transit-time ultrasonic blood flow probes placed around the middle uterine artery. Surgery was conducted on d 215 of gestation. The cows were sedated with xylazine and local anesthesia (procaine or bupivacain hydrochloride) during surgery. The surgical operations were conducted at the flank of standing cows. A transit time ultrasonic flow probe ("S" series, diameter 12 or 14 mm, Transonic Systems Inc., Ithaca, NY) was fitted surgically around the uterine artery of each cow. Surgery was completed within 2 h of anesthesia, and the animals recovered rapidly following surgery. Uterine blood flow (UBF, L/min) was recorded at 10-s intervals for 1395 min; these values were averaged to determine UBF. Cows exhibited normal gestation lengths (279.1 +/- 7.4 d), gave birth to normal healthy calves (birth weight = 40.6 +/- 6.6 kg), and had no retained placentas. The UBF increased significantly (P < 0.01) from d 225 (6.67 +/- 2.47) to d 249 (8.23 +/- 2.89) of gestation, but the latter UBF was similar to that of d 266 (8.38 +/- 2.70). The increased UBF after d 225 indicates increased demand of nutrients of fetus with the progress of gestation. The range of mean UBF varied widely among individual cows from 4.1 L/min to 12.2 L/min. Our method is useful for chronic measurement of UBF in cows for nutritional or physiological studies and does not require sophisticated facilities or special surgical technique.

Animals↗
PubMed2001

Prognostic factors affecting disease-free survival rate following surgical resection of primary breast cancer.

In order to identify the prognostic factors that significantly influence the disease-free survival rate after surgical resection of primary breast cancers, we determined tumour and lymph node grades, and immunohistochemical staining for estrogen and progesterone receptors (ER and PR), c-erbB-2, p53, bcl-2, bax and PCNA in 76 patients. Univariate analysis showed that increased grade of tumour and lymph nodes, negative immunostaining for ER, positive immunostaining for c-erbB-2, and a high PCNA index (> or = 30%) negatively influenced the disease-free survival rate, but PR, p53, bcl-2 and bax had no predictive value. Although p53 was not an independent prognostic factor by itself, the combination of p53, bcl-2, and bax proved to correlate with the disease-free survival, with the best prognosis noted in tumours negative for p53 and positive for both bcl-2 and bax, intermediate prognosis in tumours negative for p53 and positive for either bcl-2 or bax and worst prognosis in tumors negative for p53 as well as bcl-2 and bax. Tumour grade correlated positively with PCNA index, while positive staining for ER correlated negatively with tumour grade as well as with PCNA index, although this was statistically insignificant. Immunostaining of breast cancers for bcl-2 correlated negatively with tumour grade and PCNA index. Immunostaining for c-erbB-2 correlated positively with PCNA but not with tumour grade. Immunostaining for p53 tended to correlate positively with PCNA, but not with tumour grade. Immunostaining for PR and bax did not correlate with tumour grade and PCNA index. These results suggest that in addition to tumour size and lymph node involvement, immunostaining for ER, c-erbB-2, and a high PCNA index are important prognostic factors in human breast cancer. Wild-type p53 with preserved bcl-2 and bax gene products is also a favorable prognostic factor indicating breast cancer at an early stage of cancer progression.

Adult↗