Search PubMed⌕ Search

Biomedical subjects

T Aoki

Publications and source records attributed to T Aoki.

At least 217 records · Page 12Linked to original sources
PubMed2000

Development of a highly specific recombinant Toxocara canis second-stage larva excretory-secretory antigen for immunodiagnosis of human toxocariasis.

The specificity of the recombinant Toxocara canis antigen developed for the immunodiagnosis of human toxocariasis was compared with that of the excretory-secretory antigen from T. canis second-stage larvae (TES) by enzyme-linked immunosorbent assay. A total of 153 human serum samples from patients infected with 20 different helminths, including 11 cases of toxocariasis, were examined. No false-negative reactions were observed for the toxocariasis cases. When the TES was used at concentrations of 0.5 and 0.125 microg/ml, cross-reactions were observed in 79 (55.6%) and 61 (43.0%) of 142 cases, respectively. In contrast, when the recombinant antigen was tested at a concentration of 0.5 microg/ml, cross-reactions were observed in 19 (13.4%) of 142 cases. At a concentration of 0.125 microg/ml, however, the cross-reaction rate decreased sharply to only 2.1%, corresponding to 3 of 142 cases. The cross-reactions occurred with one case each of gnathostomiasis, paragonimiasis with Paragonimus miyazakii, and spirometriasis, in which high antibody titers were detected. In addition, the recombinant antigen showed negative reactions with serum samples from patients infected with Ascaris and hookworms, which are the most common parasites in the world. These findings are also supported by experiments with animals infected with Ascaris and hookworm. From these results, the recombinant antigen is highly specific for toxocariasis and may provide more reliable diagnostic results than other methods.

Animals↗
PubMed2000

Effect of steroid on hyperoxia-induced ICAM-1 expression in pulmonary endothelial cells.

Intercellular adhesion molecule-1 (ICAM-1) of the vascular endothelium plays a key role in the development of pulmonary oxygen toxicity. We studied the effect of steroid on hyperoxia-induced ICAM-1 expression using cultured endothelial cells in vitro. Human pulmonary artery endothelial cells (HPAECs) were cultured to confluence, and then the monolayers were exposed to either control (21% O(2)-5% CO(2)) or hyperoxic (90% O(2)-5% CO(2)) conditions with and without a synthetic glucocorticoid, methylprednisolone (MP). MP reduced hyperoxia-induced ICAM-1 and ICAM-1 mRNA expression in a dose-dependent manner. Neutrophil adhesion to hyperoxia-exposed endothelial cells was also inhibited by MP treatment. In addition, MP attenuated hyperoxia-induced H(2)O(2) production in HPAECs as assessed by flow cytometry. An electrophoretic mobility shift assay demonstrated that hyperoxia activated nuclear factor-kappaB (NF-kappaB) but not activator protein-1 (AP-1) and that MP attenuated hyperoxia-induced NF-kappaB activation dose dependently. With Western immunoblot analysis, IkappaB-alpha expression was decreased by hyperoxia and increased by MP treatment. These results suggest that MP downregulates hyperoxia-induced ICAM-1 expression by inhibiting NF-kappaB activation via increased IkappaB-alpha expression.

Cell Adhesion↗
PubMed2000

Properties of a calcium-activated K(+) current on interneurons in the developing rat hippocampus.

Calcium-activated potassium currents have an essential role in regulating excitability in a variety of neurons. Although it is well established that mature CA1 pyramidal neurons possess a Ca(2+)-activated K(+) conductance (I(K(Ca))) with early and late components, modulation by various endogenous neurotransmitters, and sensitivity to K(+) channel toxins, the properties of I(K(Ca)) on hippocampal interneurons (or immature CA1 pyramidal neurons) are relatively unknown. To address this problem, whole-cell voltage-clamp recordings were made from visually identified interneurons in stratum lacunosum-moleculare (L-M) and CA1 pyramidal cells in hippocampal slices from immature rats (P3-P25). A biphasic calcium-activated K(+) tail current was elicited following a brief depolarization from the holding potential (-50 mV). Analysis of the kinetic properties of I(K(Ca)) suggests that an early current component differs between these two cell types. An early I(K(Ca)) with a large peak current amplitude (200.8 +/- 13.2 pA, mean +/- SE), slow time constant of decay (70.9 +/- 3.3 ms), and relatively rapid time to peak (within 15 ms) was observed on L-M interneurons (n = 88), whereas an early I(K(Ca)) with a small peak current amplitude (112.5 +/- 7.3 pA), a fast time constant of decay (39.4 +/- 1.6 ms), and a slower time-to-peak (within 26 ms) was observed on CA1 pyramidal neurons (n = 85). Removal of extracellular calcium or addition of inorganic Ca(2+) channel blockers (cadmium, nickel, or cobalt) was used to demonstrate the calcium dependence of these currents. Addition of norepinephrine, carbachol, and a variety of channel toxins (apamin, iberiotoxin, verruculogen, paxilline, penitrem A, and charybdotoxin) were used to further distinguish between I(K(Ca)) on these two hippocampal cell types. Verruculogen (100 nM), carbachol (100 microM), apamin (100 nM), TEA (1 mM), and iberiotoxin (50 nM) significantly reduced early I(K(Ca)) on CA1 pyramidal neurons; early I(K(Ca)) on L-M interneurons was inhibited by apamin and TEA. Combined with previous work showing that the firing properties of hippocampal interneurons and pyramidal cells differ, our kinetic and pharmacological data provide strong support for the hypothesis that different types of Ca(2+)-activated K(+) current are present on these two cell types.

Aging↗
PubMed2000

Appearance of frontal midline theta activity in patients with generalized anxiety disorder.

The appearance of frontal midline theta activity (Fmθ), recognized as distinct EEG theta rhythm in the frontal midline area during performance of a mental task, reflects feelings of relief from anxiety in humans. In the present study, EEGs were recorded, and the Hamilton Rating Scale for Anxiety and the state anxiety scale of Spielberger's State-Trait Anxiety Inventory were evaluated once a week in 28 patients with generalized anxiety disorder. The Taylor Manifest Anxiety Scale and the trait anxiety scale of Spielberger's State-Trait Anxiety Inventory were used to assess anxiety before and after the tests. The present results suggest that the appearance of Fmθ might be closely related to an improvement in the anxiety symptoms associated with generalized anxiety disorder.

Adolescent↗
PubMed2000

Immunohistochemical detection and distribution of enamelysin (MMP-20) in human odontogenic tumors.

Enamelysin is a tooth-specific protease that was initially isolated from porcine enamel organ and subsequently from human odontoblasts. Since this protease is thought to play important roles in tooth development, the evaluation of enamelysin in odontogenic tumors may aid our understanding of the histogenesis and cell differentiation of such lesions. A monoclonal antibody (203-1C7) was generated against synthesized human enamelysin oligopeptide and was used to assess the immunolocalization of enamelysin in healthy developing tooth germs and various types of odontogenic lesions. In tooth germs, enamelysin expression was detected only in the secretory enamel. Thus, 203-1C7 may serve as an enamel-specific marker in the late stage of enamel matrix development and calcification. In odontogenic lesions, strong enamelysin staining was demonstrated in the immature enamel matrix of ameloblastic fibro-odontomas and odontomas. Furthermore, enamelysin was also detected in globular amyloid masses and calcified foci in calcifying epithelial odontogenic tumors, hyaline droplets, small and large mineralized areas in adenomatoid odontogenic tumors, and a portion of ghost cells in calcifying odontogenic cysts. Positive reactivity was also observed in selected tumor cells in some of these tumors. No intracellular staining for enamelysin was detected in ameloblastomas or the ameloblastic portion of ameloblastic fibro-odontomas. Also, enamelysin was not detected in dentin, dysplastic dentinoid hyaline matrices, and cementum that were present within the tumors examined. Thus, taken together, our results suggest that the enamelysin-specific monoclonal antibody (203-1C7) may be utilized as a marker of early enamel development and that enamelysin may be involved in the pathogenesis of specific odontogenic tumors.

Ameloblastoma↗
PubMed2000

Neurotrophin-3 levels in cerebrospinal fluid from children with bacterial meningitis, viral meningitis, or encephalitis.

Neurotrophin-3 levels were measured in the cerebrospinal fluid of 35 patients with bacterial meningitis, viral meningitis, or encephalitis by two-site enzyme immunoassay. Elevated cerebrospinal fluid levels of neurotrophin-3 were demonstrated in 8 of 18 patients with bacterial meningitis. Follow-up examination of the eight patients at the convalescent stage showed diminished cerebrospinal fluid levels of neurotrophin-3. In contrast, none of the 17 patients with viral meningitis or encephalitis showed an elevation of neurotrophin-3 levels in cerebrospinal fluid. No relationships were observed between neurotrophin-3 levels and cerebrospinal fluid cell numbers, cerebrospinal fluid protein levels, serum C-reactive protein concentrations, or outcome in bacterial meningitis. Since neurotrophin-3 is involved in the survival of neurons and the modulation of the immune system, neurotrophin-3 could play a neuroprotective or immunomodulatory role in bacterial meningitis.

Adolescent↗
PubMed2000

A flexible single-step detection of blotted antigen using a fusion protein between protein A and green fluorescent protein.

A green fluorescent protein mutant (S147P GFP) was fused with protein A and expressed in Escherichia coli. This fusion protein (PA-GFP147) was used in immunoblotting studies as a new detection system, designated as "flexible single-step detection (FSSD)". In FSSD, the detection of blotted antigen was done in one step, and the antigen-antibody reaction can be monitored by UV-irradiation in real time. The reaction time, therefore, can be flexibly controlled by monitoring the green fluorescence.

Animals↗
PubMed2000

New scheme of the biosynthesis of formononetin involving 2,7,4'-trihydroxyisoflavanone but not daidzein as the methyl acceptor.

Glycyrrhiza echinata cell-free extract produced isoformononetin by the 7-O-transmethylation of daidzein from S-adenosyl-L-methionine (SAM). When the yeast microsome expressing 2-hydroxyisoflavanone synthase was mixed with the cell-free extract and incubated with liquiritigenin and SAM, formononetin emerged. Furthermore, the cell-free extract yielded formononetin on incubation with 2,7,4'-trihydroxyisoflavanone and SAM. We propose a novel pathway of formononetin biosynthesis involving 2,7,4'-trihydroxyisoflavanone as the methyl acceptor.

Cell-Free System↗
PubMed2000

Chronic sulfonylurea treatment and hyperglycemia aggravate disproportionately elevated plasma proinsulin levels in patients with type 2 diabetes.

It is established that disproportionately elevated plasma proinsulin levels occur in patients with Type 2 diabetes. In the present study, multivariate analysis was performed to determine what factors contributed to the disproportionately elevated plasma proinsulin levels in Japanese patients with Type 2 diabetes (n=276). Results from univariate analysis showed that both fasting proinsulin/C-peptide ratio and proinsulin/IRI ratio were approximately 2-fold higher in patients with Type 2 diabetes than those in healthy nondiabetic subjects (n=45). In patients with Type 2 diabetes, both proinsulin/C-peptide ratio and proinsulin/IRI ratio were significantly positively correlated with fasting plasma glucose level (FPG) and HbA1c. Neither proinsulin/C-peptide ratio nor proinsulin/IRI ratio was significantly correlated with BMI. Sulfonylurea-treated subjects had a significant elevation in both proinsulin/C-peptide ratio and proinsulin/IRI ratio compared with diet-treated subjects, whereas nonsulfonylurea hypoglycemic agent-treated subjects did not. Multivariate analysis confirmed that sulfonylurea treatment and FPG were significant determinants of both fasting proinsulin/C-peptide ratio (P=0.006 and P=0.030, respectively) and proinsulin/IRI ratio (P=0.003 and P=0.016, respectively) in patients with Type 2 diabetes. These results imply that disproportionate hyperproinsulinemia may reflect an excessive overwork of beta cells under chronic sulfonylurea treatment as well as hyperglycemia.

Body Mass Index↗
PubMed2000

Beneficial effects of interferon-alpha in a case with Behçet's disease.

At the age of 20 years, a Japanese man with recurrent oral aphthae, genital ulcers, folliculitis, erythema nodosum, episodic arthritis and epididymitis was diagnosed as having Behcet's disease (BD) in 1966. He has had active ocular manifestations of BD since 1990. These symptoms recurred and never abated for a long period of time. A right renal cell carcinoma developed and he underwent right nephrectomy in April 1996. Treatment with interferon-alpha was started from June 1996 as supplemental chemotherapy. No active phase developed during administration of IFN-alpha. We suggest that IFN-alpha may play a role as an immunomodulatory agent in BD.

Adjuvants, Immunologic↗
PubMed2000

Bilirubin adsorption therapy and subsequent liver transplantation cured severe bilirubin encephalopathy in a long-term survival patient with Crigler-Najjar disease type I.

Crigler-Najjar disease (CN) type I is characterized by persistent unconjugated hyperbilirubinemia from birth. The male patient here was diagnosed with this disease as a neonate and had been treated by phototherapy. At age 16 he suddenly developed generalized convulsions, followed by impaired cognitive function. The serum level of bilirubin was extremely high (total bilirubin: 41.7 mg/dl) and there were no other detectable causes responsible for the metabolic encephalopathy. He received bilirubin adsorption therapy several times, and the bilirubin encephalopathy improved in response to the fall in the serum level of bilirubin. After this he underwent a successful liver transplantation in Australia, and recovery of his mental faculties was satisfactory. Within the subsequent 3 years epileptic abnormal discharges on the electroencephalogram disappeared. Phototherapy alone can not prevent the rise in the serum level of bilirubin in adolescent or adult patients with CN type I, therefore such patients tend to experience life-threatening bilirubin encephalopathy. To save patients with the acute onset type of bilirubin encephalopathy, sufficient bilirubin adsorption followed by liver transplantation appears to be the most recommended therapeutic approach.

Adsorption↗
PubMed2000

Intracerebellar penetrating injury and abscess due to a wooden foreign body--case report.

A 4-year-old boy presented with chopstick penetration into the cerebellum via the temporal squamosa and tentorium cerebelli, which resulted in a cerebellar abscess 1.5 years after the injury. The neuroimaging appearance of the wooden chopstick were unusual, hyperdense on computed tomography, and isointense on T2-weighted and hypointense on T2-weighted magnetic resonance imaging. Abscess aspiration and continuous drainage was performed with real-time intraoperative ultrasound guidance. The chopstick fragment was surgically removed and the patient discharged with minor neurological deficits. Wooden foreign body may show changes in properties after a long period of intraparenchymal retention. Extra care is required to remove wooden foreign bodies because of the high risk of infection.

Brain↗
PubMed2000

Evolution of peripheral lung adenocarcinomas: CT findings correlated with histology and tumor doubling time.

OBJECTIVE: This study was performed to evaluate the evolution of peripheral lung adenocarcinomas using CT findings and histologic classification related to tumor doubling time. MATERIALS AND METHODS: The subjects were 34 patients, each with an adenocarcinoma smaller than 3 cm. All patients underwent chest radiography and 10 of them had previously undergone CT more than 6 months before surgery. Tumor doubling time was estimated by examining sequential radiographs using the method originally described by Schwartz. Tumor growth was also observed by studying the changes on CT in the 10 patients who had previously undergone CT. The histologic classification (types A-F) was evaluated according to the criteria of Noguchi et al. RESULTS: Five (83%) of the six adenocarcinomas with tumor types A or B showed localized ground-glass opacity on high-resolution CT. All six tumors had a tumor doubling time of more than 1 year. Fifteen (71%) of the 21 tumors with type C showed partial ground-glass opacity mixed with localized solid attenuation on high-resolution CT. Ten (48%) of these 21 type C tumors had a tumor doubling time of more than 1 year. In types B and C, the solid component or the development of pleural indentation and vascular convergence increased during observation before surgery. All seven tumors with types D, E, and F showed mostly solid attenuation, and the tumor doubling time was less than 1 year in six (87%) of the seven tumors. CONCLUSION: Two main types of peripheral lung adenocarcinoma exist. The first type appears on CT as a localized ground-glass opacity with slow growth, and the other appears as a solid attenuation with rapid growth.

Adenocarcinoma↗
PubMed2000

High glucose level and free fatty acid stimulate reactive oxygen species production through protein kinase C--dependent activation of NAD(P)H oxidase in cultured vascular cells.

Recent studies have revealed that vascular cells can produce reactive oxygen species (ROS) through NAD(P)H oxidase, which may be involved in vascular injury. However, the pathological role of vascular NAD(P)H oxidase in diabetes or in the insulin-resistant state remains unknown. In this study, we examined the effect of high glucose level and free fatty acid (FFA) (palmitate) on ROS production in cultured aortic smooth muscle cells (SMCs) and endothelial cells (ECs) using electron spin resonance spectroscopy. Exposure of cultured SMCs or ECs to a high glucose level (400 mg/dl) for 72 h significantly increased the free radical production compared with low glucose level exposure (100 mg/dl). Treatment of the cells for 3 h with phorbol myristic acid (PMA), a protein kinase C (PKC) activator, also increased free radical production. This increase was restored to the control value by diphenylene iodonium, a NAD(P)H oxidase inhibitor, suggesting ROS production through PKC-dependent activation of NAD(P)H oxidase. The increase in free radical production by high glucose level exposure was completely restored by both diphenylene iodonium and GF109203X, a PKC-specific inhibitor. Exposure to palmitate (200 micromol/l) also increased free radical production, which was concomitant with increases in diacylglycerol level and PKC activity. Again, this increase was restored to the control value by both diphenylene iodonium and GF109203X. The present results suggest that both high glucose level and palmitate may stimulate ROS production through PKC-dependent activation of NAD(P)H oxidase in both vascular SMCs and ECs. This finding may be involved in the excessive acceleration of atherosclerosis in patients with diabetes and insulin resistance syndrome.

Animals↗
PubMed2000

Outcome of pancreatic cancer patients based on genetic lymph node staging.

We prospectively assessed the clinical value of genetic staging of lymph node metastasis in patients with pancreatic adenocarcinoma who underwent curative surgery. K-ras gene mutations were detected in the primary tumors in 18 of 25 patients with pancreatic adenocarcinoma. Among these 18 patients, mutated K-ras gene was also found in at least one lymph node in 13 patients. Of these 13 patients, seven had no evidence of histological nodal involvement and six had histological lymph node metastasis. Although there was no significant difference in overall survival rates between the pathological node-negative and -positive patients, overall survival of the five patients with nodes-negative for the mutated K-ras gene were significantly better than that of the 13 patients with genetically metastasis-positive nodes (p<0.001). Furthermore, overall survival of the six patients with genetically metastasis-positive nodes limited to peripancreatic area was significantly better than that of seven patients with genetical metastasis in lymph nodes beyond the peripancreatic areas (p=0.018). These findings suggest that detection of K-ras gene mutations in lymph nodes may be clinically useful to assess the accurate tumor staging and to stratify the patient with pancreatic adenocarcinoma who are at high or low risk for recurrence after curative surgery.

Adenocarcinoma↗
PubMed2000

[Usefulness of Doppler echocardiography in patients with ischemic cerebrovascular disease].

We carried out transthoracic Doppler echocardiography on 213 patients with ischemic cerebrovascular disease to examine cardiac functions. The prevalence of valvular regurgitation, left ventricular diastolic function (E/A ratio), and ejection fraction (EF) of each patient were studied by transthoracic Doppler echocardiography. In patients with embolic strokes, the prevalence of valvular regurgitation of the left ventricular system such as mitral regurgitation was significantly higher than that of normal controls. In contrast, there was no significant difference in the prevalence of valvular regurgitation in the right ventricular system. Although there was no significant difference in the ejection fraction between groups, the E/A ratio in patients with ischemic cerebrovascular disease showed a significantly lower value than that in normal controls. Patients with ischemic cerebrovascular disease showed a tendency to have an atherosclerotic change in the systemic arteries including cerebral and coronary arteries, reflecting an aggravation of cardiac wall compliance and diastolic dysfunction resulting in lowering of the E/A ratio. Thus, transthoracic Doppler echocardiography was useful to evaluate cardiac diastolic dysfunction and valvular regurgitation in patients with ischemic cerebrovascular disease.

Acute Disease↗