Biomedical subjects

I Aoki

Publications and source records attributed to I Aoki.

At least 55 records · Page 3Linked to original sources

PubMed1998

[Some techniques for the correction of the congenital heart disease with autologous flap].

14 living flaps in 8 children were used to repair for the congenital heart disease, because artificial material and xeno grafts were shrunk in growing children but living flaps were going to glow with children. It were possible to use the living flaps to reconstruct of pulmonary outflow in truncus arteriosus, for septoplasty in partial anomarous of pulmonary venous return and reconstruction of unloofed coronary sinus in endocardial defect with triatriatum and intraatrial tunnel in TCPC or Fontan type operation.

Cardiac Surgical Procedures↗

PubMed1998

Human platelet activation by thrombolytic agents: effects of tissue-type plasminogen activator and urokinase on platelet surface P-selectin expression.

The mechanisms that underlie reocclusion during thrombolytic therapy have not yet been clarified. The purpose of this study was to investigate the activating effects of tissue-type plasminogen activator and urokinase and the inhibitory effects of acetylsalicylic acid by measuring platelet surface P-selectin as a marker of platelet activation. After addition of urokinase (final concentration 192 U/ml, 1920 U/ml, or 19,200 U/ml) or tissue-type plasminogen activator (final concentration 120 U/ml, 1200 U/ml, or 12,000 U/ml) to platelet-rich plasma from 12 healthy persons, platelet surface P-selectin expression was measured by means of flow cytometry with an anti-CD62 monoclonal antibody. The presence of urokinase and tissue-type plasminogen activator increased platelet surface P-selectin expression in a concentration-dependent manner. In the next step, either 160 mg/day (n = 6) or 660 mg/day (n = 6) acetylsalicylic acid was administered to the 12 healthy persons, and venous blood samples were collected after 7 days of treatment. Platelet surface P-selectin expression was measured with the method used earlier and after addition of tissue-type plasminogen activator or urokinase. Although the effect of acetylsalicylic acid at 160 mg/day on P-selectin expression was minimal, a dose of 660 mg/day suppressed platelet P-selectin expression and inhibited the platelet activating effects of tissue-type plasminogen activator and urokinase in a statistically significant way. Platelets were activated by tissue-type plasminogen activator or urokinase, and this platelet activation was suppressed with administration of acetylsalicylic acid at 660 mg/day.

Aspirin↗

PubMed1998

Segmental mediolytic arteritis [correction of arteries]: a case report with review of the literature.

Segmental mediolytic arteritis is a very rare vascular disease which causes sudden intraabdominal hemorrhage. The disease is characterized by degeneration of the arterial media, followed by aneurysmal dilatation and rupture of the involved artery. Up to now, only 13 cases have been reported, and this unique disease is not fully recognized among general pathologists and physicians. Here, we present a case of segmental mediolytic arteritis involving the propria hepatic artery, which resulted in intraabdominal hemorrhage, and consequently hypovolemic circulatory disturbance. Histologically, the rupture focus showed degeneration and desquamation of the intima and media with fibrin-like material covering the exposed adventitia. Inflammatory infiltrates were only noted in the rupture focus as a secondary reactive change. Other than the rupture focus, there were two foci showing similar findings. This disease has rarely been reported and is seldom recognized as a cause of arterial rupture. In cases of sudden intraabdominal hemorrhage, segmental mediolytic arteritis should be considered as a possible cause in addition to atherosclerotic and mycotic aneurysm, traumatic injury and vasculitis syndromes.

Adult↗

PubMed1998

Mechanism of rethrombosis after thrombolytic therapy: angioscopic findings and investigation of the coagulation system in dogs.

The purpose of this study was to angioscopically observe the process of thrombolysis after intracoronary administration of thrombolytic agents and to investigate the effects of these agents on coagulation/fibrinolysis systems in dogs. The coronary endothelium was removed and thrombus formation was confirmed by angioscopy. In the tissue plasminogen activator (tPA) group (n=8), complete thrombolysis occurred in all animals, but thrombolysis was incomplete in the urokinase (UK) group (n=6). The plasma level of plasmin alpha2-plasmin inhibitor complex peaked at 15 minutes after treatment in both the tPA and UK groups. Plasma thrombin-antithrombin III (TAT) complex decreased transiently at 15 minutes after tPA administration but increased at 30 and 60 minutes (P<0.05). In the UK group, plasma TAT also showed a transient decrease followed by an increase, which was minimal compared with that in the tPA group. Plasma TAT decreased transiently after infusion of tPA and subsequently increased to above the pretreatment level, suggesting a risk of rethrombosis after successful recanalization.

Angioscopy↗

PubMed1998

[Infective endocarditis associated with ruptured aneurysm of Valsalva: aortic valve replacement after reconstruction of left ventricular outflow tract].

Infective endocarditis associated with ruptured aneurysm of Valsalva disrupted the vicinity of aortic annulus (Valsalva, valve, left ventricular outflow tract). This condition did not accept insertion of prosthetic valve at normal position. Insertion of St. Jude valve was performed after the reconstruction of outflow tract with a xenopericardial patch. Proportionate sutures for the right cusp part was taken through the infundibular muscle at the right ventricular side, not in the pericardial patch. The bileaflet valve functioned properly in spite of the oblique insertion.

Adult↗

PubMed1998

[An experience with peeling technique with curettage of open mitral commissurotomy].

Ideally, the mitral valve is a soft, thin and flexible tissue. In severe rheumatic mitral stenosis, however, its motion is restricted due to the adhesion of fibrous tissues and calcium. Open mitral commissurotomy was not effective in successfully restoring it to normal condition. By using a peeling technique with curettage during open mitral commissurotomy, the calcium and fibrous tissues are sufficiently removed. This method is effective in improving the flexibility of the anterior leaflet of the restricted mitral valve.

Cardiac Surgical Procedures↗

PubMed1998

Evaluation of Epstein-Barr Virus infection in hypopharyngeal carcinomas from 37 Japanese patients.

Thirty-seven biopsy specimens from primary sites, 18 surgically removed metastatic neck nodes, and 18 surgically removed primary sites from 37 patients with hypopharyngeal carcinoma (HPC) were evaluated for the presence of Epstein-Barr Virus (EBV) infection by in situ hybridization (ISH) and polymerase chain reaction (PCR). Although some of normal lymphocytes in 6 of 18 metastatic nodes were positive by ISH, there were no positive results from HPC tumor cells themselves. Our results indicate that EBV-infected non-neoplastic cells such as lymphocytes can be a cause of false positivity, if a study were conducted with PCR alone. Because ISH for EBV-encoded early RNAs was highly sensitive, even more sensitive than PCR from paraffin-embedded samples in our study, this method should be the first choice for identification of EBV infection to avoid false positives.

Adult↗

PubMed1997

Intranasal immunization of a DNA vaccine with IL-12- and granulocyte-macrophage colony-stimulating factor (GM-CSF)-expressing plasmids in liposomes induces strong mucosal and cell-mediated immune responses against HIV-1 antigens.

A DNA vaccine constructed with the CMV promoter conjugated to env gp160 and rev genes has been shown to induce an effective Th1-type immune response when inoculated via an intramuscular route. In the present study, we obtained high levels of both humoral and cell-mediated immune activity by intranasal administration of this DNA vaccine. The production of mucosal IgA Ab in feces and vaginal fluid was stimulated significantly by intranasal DNA administration. This route of administration resulted in a significant level of HIV-1-neutralizing Abs in feces and serum. Cytokine assays revealed that intranasal administration of this DNA vaccine induces a Th2-type immune response. Interestingly, cationic liposomes greatly enhanced these activities. Abs against HIV-1 were present for at least 10 mo. Coadministration of the DNA vaccine with IL-12- and granulocyte/macrophage-CSF-expressing plasmids induced high levels of HIV-specific CTLs and an increase in delayed type hypersensitivity when administered by the intranasal route. These results clearly demonstrate that intranasal administration of this DNA vaccine with liposomes, together with IL-12- and/or granulocyte/macrophage-CSF-expressing plasmids, induces a strong level of anti-HIV-1 immune response.

Administration, Intranasal↗

PubMed1997

Enhancement of cell-mediated immunity against HIV-1 induced by coinnoculation of plasmid-encoded HIV-1 antigen with plasmid expressing IL-12.

Previous investigations have demonstrated that CTL may play an important role in suppressing the disease progression of HIV infection. In this study, we inoculated mice with IL-12 expression plasmid together with plasmid-encoding HIV-1 envelope to enhance CTL activity by activating a Th1-type response. The results of delayed-type hypersensitivity using the footpad swelling response and of CTL activity clearly showed that HIV-1-specific cell-mediated immunity was enhanced by inoculation of the IL-12 expression plasmid. Quantitation of cytokine in the sera of IL-12-inoculated mice revealed that IFN-gamma significantly increased. The enhanced cell-mediated immunity responses were abrogated by combined administration of the IL-12 expression plasmid and neutralizing anti-IFN-gamma Ab. Together, these results suggest that enhanced virus-specific cell-mediated immunity occurred via an endogenously produced IFN-gamma by inoculation of IL-12 expression plasmid.

AIDS Vaccines↗

PubMed1997

Highly sensitive high-performance liquid chromatographic determination method for a new erythromycin derivative, EM523, and its major metabolites in human plasma and urine using post-column tris(2,2'-bipyridine) ruthenium(III) chemiluminescence detection.

A method for the simultaneous determination of de(N-methyl)-N-ethyl-8,9 -anhydroerythromycin A 6,9-hemiacetal (EM523, I) and its three metabolites in human plasma and urine has been developed using high-performance liquid chromatography (HPLC) with chemiluminescence (CL) detection. Plasma and urine samples spiked with erythromycin as an internal standard were extracted with a mixture of dichloromethane and diethyl ether under alkaline conditions. The organic layer was evaporated under a stream of nitrogen gas. The reconstituted sample was injected into an HPLC apparatus and separated on an ODS column using a gradient elution method. The eluate was reacted on-line with a mixture of tris(2,2'-bipyridine) ruthenium(II) and peroxodisulfate, and the generated CL intensity was detected. Optimization of the CL reaction conditions resulted in a sensitive and stable CL intensity for the determination of I and its metabolites. The recovery of each compound from human plasma and urine, and the sensitivity, linearity, accuracy and precision of the method were satisfactory. The lower limits of quantitation for each compound using 0.2 ml of plasma and 0.1 ml of urine were 1 and 10 ng/ml, respectively. This method has been used for the determination of 1 in samples from clinical trials.

2,2'-Dipyridyl↗

PubMed1997

Immunomodulatory effects of a plasmid expressing B7-2 on human immunodeficiency virus-1-specific cell-mediated immunity induced by a plasmid encoding the viral antigen.

B7 co-stimulation is essential for activating resting T cells following antigen recognition by the T cell receptor. To determine whether B7 has adjuvant activities on human immunodeficiency virus type-1 (HIV-1)-specific immunity induced by inoculation of a plasmid encoding HIV-1 env and rev (DNA vaccine), B7-1 and B7-2 expression plasmids were co-inoculated with the DNA vaccine. The delayed-type hypersensitivity response and cytotoxic T lymphocyte (CTL) activity were significantly enhanced when B7-2 expression plasmid was co-inoculated with the DNA vaccine, but were unaffected when the B7-1 expression plasmid was used with the vaccine instead. The immunological response enhanced by B7-2 decreased below the level of mice immunized with the DNA vaccine in combination with CTLA4Ig, an inhibitor of the B7/CD28 co-stimulatory signal, suggesting that this signal is critical for the enhanced response induced by co-inoculation of the DNA vaccine and B7-2 expression plasmid. This enhancement appeared to occur via an interferon-gamma (IFN-gamma)-dependent mechanism, as combined administration of the B7-2 plasmid and neutralizing anti-IFN-gamma antibody abrogated the virus-specific cell-mediated immunity. These results suggest that this gene-based co-inoculation strategy using HIV-1 viral antigen and B7-2 co-stimulatory molecule could be a powerful means of combating HIV-1 infection.

AIDS Vaccines↗

PubMed1997

Adult ganglioneuroblastoma of the anterior mediastinum.

A case of ganglioneuroblastoma occurring in the anterior mediastinum of a 79 year-old man is reported. The tumor was mainly composed of neuroblasts with occasional ganglion cells. Foci of melanin-laden cells were also identified. Immunohistochemistry revealed that the tumor cells showed both schwannian and melanocytic differentiation with immunoreactivity to anti-S100 protein and anti-HMB45 antibodies. In addition, the tumor contained several microcysts lined by squamous epithelial and one lymphoid tissue abundant in T lymphocytes, which appeared to be derived from thymic tissue. This case is unique in that neuroblastoma group tumors including ganglioneuroblastoma is uncommon in the elderly and in the thymic region, and rarely shows melanocytic differentiation. To the best of our knowledge, this case is a tumor of neuroblastoma group occurring in the eldest patient.

Aged↗

PubMed1997

Platelet-dependent thrombin generation in patients with hyperlipidemia.

OBJECTIVES: We evaluated coagulability as determined by platelet-dependent thrombin generation in hypercholesterolemic patients before and after treatment with pravastatin and in hypertriglyceridemic patients to investigate the usefulness of coagulability as an index of atherosclerosis and to determine the importance of treating hyperlipidemia. BACKGROUND: An understanding of the interaction between platelets and the plasma coagulation system is important for clarifying the mechanism of the procoagulant process. METHODS: We assessed coagulability in 58 patients with hypercholesterolemia (serum total cholesterol level > or = 220 mg/dl, age 56.5 +/- 1.5 years [mean +/- SEM]), 37 patients with hypertriglyceridemia (serum triglyceride level > or = 200 mg/dl, age 59.5 +/- 1.7 years), 13 patients with hypercholesterolemia plus hypertriglyceridemia (age 51.4 +/- 3.1 years) and 75 normal subjects (age 52.2 +/- 1.7 years). We also studied platelet-dependent thrombin generation in patients with hypercholesterolemia before and after treatment with pravastatin. Calcium chloride was added to 0.5 ml of platelet-rich plasma (150 x 10(9)/liter) to initiate coagulation. Ten microliters of the sample was transferred into 90 microliters of 3.8% sodium citrate at 10-min intervals for 30 min. A chromogenic substrate, S-2238, was added to each sample, and absorbance was measured spectrophotometrically at a wavelength of 405 nm to determine thrombin generation. RESULTS: Platelet-dependent thrombin generation was increased in patients with hypercholesterolemia and patients with hypercholesterolemia plus hypertriglyceridemia (p < 0.01) compared with patients with hypertriglyceridemia and control subjects. Treatment with pravastatin normalized thrombin generation. CONCLUSIONS: Hypercholesterolemia, but not hypertriglyceridemia, was associated with increased platelet-dependent thrombin generation. Pravastatin normalized the generation of thrombin.

Adult↗

PubMed1997

HIV-1-specific cell-mediated immunity is enhanced by co-inoculation of TCA3 expression plasmid with DNA vaccine.

We developed a candidate DNA vaccine designated pCMV160IIIB with pcREV (pCMV160IIIB/REV) that encodes gp160 of human immunodeficiency virus (HIV)-1IIIB and Rev driven by the cytomegalovirus (CMV) promotor. This vaccine induced both HIV-1-specific antibodies and cytotoxic T lymphocyte (CTL) activity. In the present study, we inoculated the TCA3 expression plasmid into mouse skeletal muscle with pCMV160IIIB/REV to determine whether this cytokine expression plasmid was able to modify the immune response. Results of a delayed-type hypersensitivity (DTH) assay using footpad swelling as well as those of a CTL assay clearly demonstrated that cell-mediated immunity (CMI) elicited by co-inoculation of pCMV160IIIB/REV with the TCA3 expression plasmid was markedly enhanced compared with that obtained using pCMV160IIIB/REV alone. When TCA3 expression plasmid was inoculated with anti-TCA3 antibody, enhancement of the DTH response was suppressed below the level of that obtained with pCMV160IIIB/REV alone. The titre of HIV-1-specific IgG2a was slightly high when pCMV160IIIB/REV was co-inoculated with this plasmid, suggesting that T-helper 1 (Th1) response was predominant in TCA3-inoculated mice. Infiltration of mononuclear cells was seen in the muscles at sites where TCA3 expression plasmid had been inoculated. Our present data suggest that TCA3 expression plasmid has potent adjuvant activity that results in an augmented CMI response.

AIDS Vaccines↗

PubMed1997

Investigation of morphological change of lateral and midline fluid percussion injury in rats, using magnetic resonance imaging.

OBJECTIVE: Investigating the time course of morphological changes in experimental traumatic brain injury (TBI) in vivo helps to clarify the mechanism of TBI and develop new therapeutic modalities. We examined the morphological changes in experimental TBI, using magnetic resonance imaging (MRI) in a rat model. METHODS: We produced lateral fluid percussion injury (LFP) and midline fluid percussion injury (MFP) in rats, using the Yamaki fluid percussion device. The rats were divided into four groups: LFP, MFP, sham LFP, and sham MFP. MRI was performed with a 4.7-T magnetic resonance apparatus 2 days and 90 days after the induction of injury. T1-, T2-, and T2- weighted images were obtained using a surface coil. RESULTS: Hemorrhage, contusion, and brain edema in LFP models were detected on the 2nd day after injury, and the necrotic tissue was absorbed and replaced by cerebrospinal fluid on the 90th day. In MFP animals, we detected a small hemorrhage in the corpus callosum with minimal brain edema around the hemorrhage on the 2nd day after injury, and on the 90th day, enlarged ventricles and cisterns were observed, indicating brain atrophy. CONCLUSION: MRI, therefore, is useful for plotting morphological changes in experimental TBI in vivo. We report the novel and clinically important finding of brain atrophy after experimental TBI.

Animals↗

PubMed1997

Monophosphoryl lipid A enhances both humoral and cell-mediated immune responses to DNA vaccination against human immunodeficiency virus type 1.

To enhance immunity induced by DNA vaccination against human immunodeficiency virus type 1 (HIV-1), we evaluated the efficacy of monophosphoryl lipid A (MPL), an adjuvant of bacterial origin. BALB/c mice were intramuscularly injected with immunogenic DNA, encoding the env and rev genes of the HIV-1(IIIB) strain, formulated with MPL dissolved in different vehicles (MPL in stable emulsion and MPL in aqueous formulation). The sera from mice immunized with the two preparations of MPL revealed 2(6) to 2(9) times higher HIV-1-specific immunoglobulin G (IgG) titers than the sera from mice immunized without MPL. In virus neutralization tests for HIV-1(IIIB), by p24 assay and antifusion assay of infected MOLT-4 cells, MPL tends to elicit antibody more protective than antibody elicited without adjuvant. MPL also elicited stronger delayed-type hypersensitivity and cytotoxic-T-lymphocyte activity against HIV-1(IIIB) compared to DNA alone. HIV-1-specific IgG subclass analysis showed that MPL tends to facilitate IgG2a production, suggesting enhancement of a predominant T-helper-type-1 response, and this enhancement may help to facilitate protective-antibody induction. Furthermore, a chloramphenicol acetyltransferase (CAT) assay was employed to determine whether MPL affected the gene expression process. Interestingly, both MPL preparations reduced CAT activity in the muscle injected with CAT expression vector but increased anti-CAT antibody production. These results indicate that MPL acts as an effective adjuvant for immunogenic DNA injection despite reduced expression of encoding protein in muscle. We conclude that MPL has a strong adjuvant effect on DNA vaccination against HIV-1.

AIDS Vaccines↗

PubMed1997

Hemorrhagic and nonhemorrhagic stroke: diagnosis with diffusion-weighted and T2-weighted echo-planar MR imaging.

PURPOSE: To determine if diffusion- and T2-weighted echo-planar magnetic resonance (MR) imaging can be used to detect acute hemorrhagic stroke and to differentiate hemorrhagic from nonhemorrhagic stroke. MATERIALS AND METHODS: A total of 118 examinations (diffusion- and T2-weighted MR imaging) in 19 patients with 27 nonhemorrhagic strokes and in six patients with seven hemorrhagic strokes were performed. The ratios of apparent diffusion coefficient and of signal intensity on T2-weighted MR images in lesions to those in contralateral control areas were calculated. RESULTS: Decreased ADC was shown in lesions of acute (0-3 days) hemorrhagic stroke, as well as in lesions of acute nonhemorrhagic stroke. Hypointense areas were seen on T2-weighted MR images in patients with acute hemorrhagic stroke, in contrast to normal to increased signal intensity in those with acute nonhemorrhagic stroke. Apparent diffusion coefficient tended to remain decreased in hemorrhagic stroke lesions even 100 days after onset, in contrast to the increased coefficient in nonhemorrhagic stroke lesions at the late chronic stage (31 days or older). CONCLUSION: Diffusion- and T2-weighted echo-planar MR imaging can be used to detect and distinguish between acute hemorrhagic and nonhemorrhagic stroke.

Acute Disease↗

PubMed1997

[Principles and clinical applications of diffusion weighted echo planar MR imaging].

The ultrafast capability of echo planar imaging(EPI) made diffusion-weighted MRI (DWI) measurements practical, without the need of head fixation and without the need to exclude patients unable to hold still. The DW hyperintensity and reduced apparent diffusion coefficient(ADC) were observed in all hyperacute strokes, initially at 2.5 hours. In contrast to decreased ADC within 10 days and DW hyperintensity within 30 days, ADC was increased without DW hyperintensity in chronic stage. This suggests that DWI can discriminate between acute and chronic strokes. Furthermore, DWEPI and T2-weighted EPI were also be useful to detect and distinguish acute hemorrhagic stroke from nonhemorrhagic stroke. This review highlighted the promising technique of DWEPI to examine stroke patients in routine clinical practice.

Animals↗