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Biomedical subjects

J Okada

Publications and source records attributed to J Okada.

At least 109 records · Page 6Linked to original sources
PubMed1993

Studies of new short-period method for delayed contact hypersensitivity assay in the guinea pig. (I). Development and comparison with other methods.

A new method for delayed contact hypersensitivity assay of chemical compounds in guinea pigs, a short-period method (14 days) with a high detection sensitivity, has been developed. The new method was as follows; a combination of a Freund's complete adjuvant (FCA, undiluted) intradermal injection and a 24-h occlusive patch on a guinea pig was performed 2x at an interval of 4 days and challenged by non-occlusive topical application 11 days after the first sensitization (with benzyl alcohol during test development). Acanthosis and spongiosis in the epidermis and mononuclear cell infiltration into the dermis were observed histopathologically at the skin reaction site. This newly developed method (adjuvant and 24-h occlusive patch 2x test: AP2 test) could equally and/or better detect the allergenicities of 6 other chemical compounds (bromostyrol, citronellal, benzyl salicylate, p-aminobenzoic acid ethyl ester, p-phenylenediamine and formaldehyde) as compared with the cumulative contact enhancement test (CCET) and the guinea pig maximization test (GPMT).

Animals↗
PubMed1993

Studies of new short-period method for delayed contact hypersensitivity assay in the guinea pig. (2). Studies of the enhancement effect of cyclophosphamide.

The enhancement effect of cyclophosphamide on the delayed contact hypersensitivity reaction of chemical compounds was studied in Hartley albino guinea pigs. A series of assay procedures, combining the AP2 test (adjuvant and 24-h occlusive patch 2x test, as previously reported) with intraperitoneal cyclophosphamide administration, were examined. The newly developed method was as follows; cyclophosphamide 200 mg/kg intraperitoneal administration 3 days before the 1st sensitization of the AP2 test (cyclophosphamide, adjuvant and 24-h occlusive patch 2x test: CAP2 test). Comparing the CAP2 test with the AP2 test, the cumulative contact enhancement test (CCET) and the guinea pig maximization test (GPMT), the CAP2 test equally and/or better enabled the detection of allergenicities not only of strong allergens such as bromostyrol, citronellal, p-phenylenediamine and formaldehyde, but also of weak allergens such as benzyl salicylate and p-aminobenzoic acid ethyl ester. Acanthosis and spongiosis in the epidermis and mononuclear cell infiltration into the dermis at the skin reaction site were histopathologically observed. Cyclophosphamide effectively enhanced the delayed contact hypersensitivity reaction of weak allergens.

Allergens↗
PubMed1993

Increase in nitric oxide and cyclic GMP of rat cerebellum by radio frequency burst-type electromagnetic field radiation.

1. Using rat cerebellum supernatant, the effects of radio frequency (RF) burst-type electromagnetic (EM) field radiation on the production of cyclic GMP were examined under various conditions. The radiation was generated by a generator coil, and set at a 10 MHz radiation frequency, a 50% burst time, a 10 kHz burst rate and a 5 V peak-to-peak generator voltage. 2. When the cerebellum supernatant was incubated with both exogenous L-arginine (nitric oxide (NO) donor) and NADPH, and irradiated by an RF burst-type EM field, the production of cyclic GMP was increased significantly from a level of 21-22 nmol min-1 (g tissue)-1 to 25-26 nmol min-1 (g tissue)-1. By contrast, such an effect was not found when the cerebellum supernatant was irradiated by an RF volley-type EM field. 3. When neither L-arginine nor NADPH were added to the cerebellum supernatant, the production of cyclic GMP was lowered to a level of 6 nmol min-1 (g tissue)-1 and the radiation effect was not found. When the cerebellum supernatant was chelated with EDTA, the production of cyclic GMP was lowered to a level of 7 nmol min-1 (g tissue)-1 and the radiation effect was not found. 4. Incubation with Methylene Blue, a guanylate cyclase inhibitor, lowered the production of cyclic GMP to a level of 10-12 nmol min-1 (g tissue)-1, and the radiation effect did not occur. On incubation with a NO synthase inhibitor, either NG-methyl-L-arginine or N omega-nitro-L-arginine methyl ester, the production of cyclic GMP was lowered to a level of 10-12 nmol min-1 (g tissue)-1 or 5-9 nmol min-1 (g tissue)-1 respectively, and the radiation effect was not observed. 5. Using electrochemical NO probes, the production of NO in the cerebellum supernatant was detected. The concentration of NO increased gradually after the onset of the EM field radiation. The radiation effect persisted, and reached a maximum after the cessation of the radiation. 6. In an in vivo study, the arterioles of the frog web were dilated by the radiation, and this radiation effect was almost completely abolished by the addition of a NO synthase inhibitor. This indicates that radiation activates NO synthase and ultimately induces vasodilatation.

Amino Acid Oxidoreductases↗
PubMed1993

Inhibition of appearance of pH-dependent virus-cell fusion by neutralizing monoclonal antibodies to transmissible gastroenteritis virus.

Five MAbs, which showed neutralizing (NT) activity and recognized S (previously designated E2) glycoprotein of TGE virus TO-163, inhibited cell fusion by TGE virus in IB-RS-2 cells. Other S-specific MAbs with no NT activity did not inhibit the cell fusion. The results indicate that a neutralization epitope is same or very close to a fusion active site. The kinetics of membrane fusion following a reduction in pH were also investigated. The cell fusion appeared between 2 and 6 hr after the binding medium was added.

Animals↗
PubMed1993

Improved identification of Staphylococcus aureus using a new agglutination test. Results of an international study.

A new reagent for the identification of Staphylococcus aureus, SLIDEX STAPH-KIT, operates on the principle of a latex and red blood cell combination agglutination: red blood cells are coated with fibrinogen for the detection of clumping factor, and latex particles are sensitized with anti-S. aureus serotype 18 monoclonal antibody for the detection of protein A and antigen 18. French strains belonging to serotype 18 are methicillin-resistant. The performance of this reagent was compared with STAPHYSLIDE and STAPHAUREX in Europe (France, Germany, Italy), in the United States and in Japan using 548 methicillin-resistant S. aureus strains, 392 methicillin-sensitive S. aureus strains, and 441 non-aureus staphylococci. The specificity of the three reagents was equivalent (98.8% for SLIDEX STAPH-KIT, 99.1% for STAPHYSLIDE, 98.1% for STAPHAUREX). SLIDEX STAPH-KIT (97.3%) was more sensitive than STAPHYSLIDE (93.5%) and STAPHAUREX (89.7%) for all S. aureus strains due to a higher rate of identified methicillin-resistant S. aureus strains.

Agglutination Tests↗
PubMed1993

[Assay of anticardiolipin antibodies and its clinical significance].

In some individuals, the presence of antibodies to negatively charged phospholipids, currently measured as the lupus anticoagulant, and anticardiolipin antibodies is associated with certain clinical features, particularly a predisposition to both arterial and venous thromboses, thrombocytopenia, and spontaneous abortion. This syndrome is seen in patients with systemic lupus erythematosus (SLE). However, methods for measuring anticardiolipin antibody, especially epitope of anticardiolipin antibody which is not considered cardiolipin itself, but rather a complex of cardiolipin and beta 2-glycoprotein I are not well defined. Although many hypotheses have been proposed to explain the relation between antiphospholipid antibodies and thrombosis, the pathogenesis of thrombosis remains unclear. In this article, some problems in assaying anticardiolipin antibody, characteristics of antiphospholipid antibodies and the clinical significance of these antibodies are reviewed and discussed.

Antibodies, Anticardiolipin↗
PubMed1992

Transmitter substances contained in the petrosal ganglion cells determined by a double-labeling method in the rat.

The presence of glutamate (Glu), aspartate (Asp) and substance P (SP) in the petrosal ganglion of rats anesthetized with pentobarbital sodium was studied using retrograde labeling of the carotid sinus nerve (CSN) with horseradish peroxidase (HRP) in combination with immunohistochemistry. (i) The incidence of HRP/Glu-labeled cells was the highest (32%, n = 3), followed in order by HRP/Asp-labeled cells (23%, n = 3) and HRP/SP-labeled cells (6%, n = 3). (ii) No significant difference was observed in the average diameter of HRP/Glu- and HRP/Asp-labeled cells, but the average diameter of HRP/SP-labeled cells was significantly larger than that of HRP/Glu- and HRP/Asp-labeled cells (P < 0.01). These results suggest that Glu may coexist with Asp, and SP-containing cells may form a different population from Glu- and Asp-containing cells in the petrosal ganglion. The physiological role of these transmitter substances is discussed.

Animals↗
PubMed1992

[Evaluation of the alkaline-phosphatase labeled DNA probes for Mycobacterium tuberculosis and Mycobacterium avium complex].

Non-radioisotopic, alkaline phosphatase-labeled DNA (AP-DNA) probe tests for the identification of Mycobacterium tuberculosis complex (Mtb) and Mycobacterium avium complex (MAC) were evaluated. The overall agreement, sensitivity and specificity of the AP-DNA probes for Mtb and MAC were 100% respectively compared with the conventional biochemical method. Because the procedure is rapid (it can be completed approximately 120 min), safe (it does not use radioisotopes) and convenient (it does not need the special equipment to be performed), it can be easily performed in any clinical laboratory.

Alkaline Phosphatase↗
PubMed1992

[A case of the eosinophilia-myalgia syndrome].

The Eosinophilia-myalgia syndrome (EMS) is a recently described clinical entity consisting of severe myalgia and eosinophilia that has ascribed to the ingestion of the amino acid L-tryptophan. Over 1500 cases of EMS have been reported to the Centers for Disease Control of United States as of June 1990. We report a case of EMS associated with the ingestion of L-tryptophan. A 24-year-old woman was admitted to our hospital due to severe myalgia. She had swelling on extremities and eosinophilia (1880/mm3). Full thickness biopsy of affected portion showed inflammation of fascia with eosinophils and histiocytes, which were compatible with eosinophilic fasciitis. She had a history of ingestion of fitness protein tablets bought at Hawaii for 3 months from Sep. to Dec. 1989, which contained the amino acid L-tryptophan. On the basis of these findings, we diagnosed her as EMS. It is suggested that this case is rare and important in Japan.

Adult↗
PubMed1992

[Analysis of stereoisomers involved products of synthesized 18F-2-deoxy-2-fluoro-D-glucose by 1H-NMR spectroscopy].

18F-2-fluoro-2-deoxy-D-mannose (FDM) is eventually involved in side products of 18F-2-fluoro-D-glucose (FDG) synthesized by the acetylhypofluorite method. We attempted the measurement of existence ratio of FDM and FDG, FDM alpha and FDM beta, FDG alpha and FDG beta by 400 MHz 1H-NMR spectroscopy. The ratio of FDM to FDG were 4.0%. The amounts of FDG beta were much larger than those of FDG alpha. The difference between the amounts of FDM alpha and FDM beta were not significant. 1H-NMR spectroscopy could be utilized in quantitative analysis of products and byproducts in cyclotron chemicals. The FDM in FDG synthesized in our cyclotron system was not considered to affect a lot of influence in PET study.

Deoxyglucose↗
PubMed1992

[Visualization of the female breast in bone scintigraphy].

Breast cancer incidence rates in Japan have more than doubled in the decade between 1975 and 1985 due to a well-established and affluent Western life-style. One hundred patients having breast cancer, 107 patients having mastectomies, and 243 patients having no breast cancer were reviewed for whole body and spot views of bone scintigraphy with 99mTc-MDP. The frequency of positive breast uptake in patients with no breast cancer showed a maximum in those patients between the ages of 30 and 40, with a progressive rise and fall before and after the peak, respectively. Patients between the ages of 50 and 60 with breast cancer showed a maximum uptake of 83%, while those patients between the ages of 70 and 80 with breast cancer showed an uptake higher than 50%. There was a markedly higher breast uptake ratio in the breast cancer group compared to the breast cancer free group. Although this scanning agent was of no value in recognition of tumor localization from breast uptake, we have to suspect a high incidence of cancer existence whenever there was unilateral increased breast activity. Even though the mechanism of 99mTc-MDP uptake by breast tissue is unknown, breast concentration of 99mTc-MDP appears to be influenced by hormones, especially estrogen.

Adolescent↗
PubMed1992

[Therapeutic efficacy of norfloxacin for experimental osteomyelitis in rabbits].

Norfloxacin (NFLX), a new quinolone antibiotic agent, was evaluated for its efficacy in experimental osteomyelitis in rabbits. Osteomyelitis was induced in male rabbits by the inoculation of 10(7) CFU/ml (0.1 ml) of Staphylococcus aureus (MIC for NFLX: 0.78 micrograms/ml) with 0.4 ml of 3% sodium tetradecyl sulphate into the medullary cavity of the proximal tibia. The rabbits were divided into 3 different groups of 4 animals each. The animals in 2 groups were orally administered with NFLX; 100 mg/kg once-daily (group 2) and 50 mg/kg twice-daily (group 3) for 7 days from the 6th hour after inoculation. Group 1 was established as a control without administration of NFLX. All animals were sacrificed on the 7th day after inoculation. Acute osteomyelitic changes were found microscopically in all animals in group 1. In each of the 2 therapeutic groups, incidence of microscopic changes was 50% associated with remission of S-sialic acid value. Thus, NFLX may be considered a useful antimicrobial agent for the treatment of suppurative osteomyelitis.

Animals↗
PubMed1992

[Abnormal findings of magnetic resonance imaging (MRI) in patients with systemic lupus erythematosus involving the brain].

To elucidate the clinical significance of MRI on CNS-SLE, MRI and CT scans were performed in 35 patients with SLE, of 18 patients who had CNS manifestations at the time of MRI examinations. The investigations were also carried out with 17 patients without CNS-SLE. The rate of detection of abnormal findings on MRI in patients with CNS-SLE was 77.2% (14/18), which was high, as compared with the rate of those on CT scans (50%: 9/18). Especially, all of 4 patients with seizure and 3 patients with encephalopathy showed abnormal MRI findings, although respectively 50% and 33.3% of them had abnormal CT scan findings. MRI findings were classified into 4 groups as below: 1) Large focal are as of increased signal intensity at T2 weighted image. These were observed in 2 of 4 patients with seizure and 1 of 3 patients with encephalopathy, which were completely resolved after treatment. 2) Patchy subcortical foci of increased signal intensity at T2 weighted image. These were observed in 11 of 18 CNS-SLE and 7 of 17 without CNS-SLE, which were not detected by CT scan. 3) All of six patients with cerebral infarctions showed high signal intensity areas at T2 weighted image and low signal intensity areas at T1 weighted image. 4) Normal findings were observed in 4 of 18 CNS-SLE (22.2%). We concluded that MRI is useful for the evaluation of CNS-SLE and provides more information than CT scan.

Adolescent↗
PubMed1992

Positron emission tomography using fluorine-18-fluorodeoxyglucose in malignant lymphoma: a comparison with proliferative activity.

To evaluate the relationship between PET using 18F-fluorodeoxyglucose (FDG) and pathological findings and to compare indices obtained by FDG-PET, FDG-PET was performed in 23 patients with untreated malignant lymphoma. Three indices obtained by FDG-PET, tumor-to-normal contrast ratio (TCR), distribution absorption ratio (DAR), k1k2/(k2 + k3), correlated with proliferative activity which was pathologically estimated both by mitotic count and by proportion of cells in all phases of the cell cycle. The relationship did not significantly change according to which of the three indices was chosen. FDG-PET, which shows the proliferative activity of tumors, is considered to be a useful method for managing tumors.

Adult↗
PubMed1991

[Magnetic resonance imaging of small nasopharyngeal tumors].

Magnetic resonance (MR) images of 9 patients with a small nasopharyngeal tumor were examined, and among them three cases were evaluated with Gd-DTPA enhancement technique. All cases showed no asymmetry of parapharyngeal space, but they presented neck lymph nodes swelling. These cases were proved malignant by surgical procedures and the blind biopsy. MR findings of levator and tensor veli palatini muscles and retropharyngeal lymph nodes were retrospectively evaluated in correlation with endoscopic examination and biopsy. In six cases among 9 patients, MR images demonstrated tumors on the lateral wall of nasopharynx. Infiltration of levator veli palatini muscle was an especially important earlier sign of nasopharyngeal tumor invasion because the levator veli palatini muscle belongs to the intrapharyngeal muscle group. Endoscopic examination could not reveal any abnormal lesion in three cases among these 6 cases. No definite signal intensity difference between tumor and pharyngeal mucosa was shown on both T1 and T2 weighted images. But the normal pharyngeal mucosa had demonstrated higher intensity than tumor with Gd-DTPA administration. So the enhanced nasopharyngeal MR imaging made the clear intensity difference between tumor and muscle tissue. It was the conclusion that MR imaging was superior to X-CT in detecting small nasopharyngeal tumor.

Adult↗