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Biomedical subjects

S Oka

Publications and source records attributed to S Oka.

At least 253 records · Page 14Linked to original sources
PubMed1995

KatG sequence deletion is not the major cause of isoniazid resistance in Japanese and Yemeni Mycobacterium tuberculosis isolates.

One of the mechanisms of isoniazid resistance to Mycobacterium tuberculosis has been proved to be the chromosomal deletion of katG. Based on this finding, 22 isoniazid-resistant isolates of M. tuberculosis obtained in Japan and Yemen were analysed for katG by polymerase chain reaction and catalase activity. Only six (27%) of the 22 isolates were compatible with the mechanism (lack of amplification of katG and loss of catalase activity). In contrast, eight isolates (36%) were katG positive but catalase activity-negative and eight (36%) were positive for both factors, indicating that isoniazid resistance is multifactorial and the deletion of katG was not the major cause of resistance in the isolates examined in this study.

Bacterial Proteins↗
PubMed1995

Ontogenetic development of neuropeptide Y-like-immunoreactive cells in the gastroenteropancreatic endocrine system of the dogfish.

This immunocytochemical study was carried out to elucidate the ontogenetic development of neuropeptide Y-like-immunoreactive cells in the gastroenteropancreatic endocrine system of the cloudy dogfish, Scyliorhinus torazame. Immunostained cells first appeared in the pancreas of the embryo at the 15-mm stage, and were also detected in the vitello-intestinal duct of the yolk stalk at the 20-mm stage. These cells were polymorphic, with occasional processes that were sometimes directed toward the vascular wall or into the cavity of the vitello-intestinal duct. At the 34-mm stage, immunostained cells could also be found in the proximal part of the spiral intestine and, by the 74-mm stage, immunopositive cells were present in the gastric mucosa. In the gut and pancreas, the cells gradually increased in number with development, whereas in the vitello-intestinal duct and internal yolk sac, they decreased and seemed to disappear following hatching. Thus, in juveniles, the distribution of the neuropeptide Y-like-immunoreactive cells in the gastroenteropancreatic endocrine system had attained that of adults. Electron-microscopic immunocytochemistry demonstrated that, in the labeled cells of the vitellointestinal duct, the neuropeptide Y-like antigen was located in cytoplasmic granules, as in the cells of the gut and pancreas.

Animals↗
PubMed1995

Detection of anti-cord factor antibodies in intestinal tuberculosis for its differential diagnosis from Crohn's disease and ulcerative colitis.

We have developed a diagnostic method for pulmonary tuberculosis by detecting antibody to cord factor using enzyme-linked immunosorbent assay (ELISA). This study was to evaluate the usefulness of our method for a diagnosis of intestinal tuberculosis, and especially its ability to differentiate this disease from other inflammatory bowel diseases. Antibodies of the immunoglobulin G class against cord factor (trehalose-6,6'-dimycolate) from 27 patients with intestinal tuberculosis, 16 patients with Crohn's disease (CD), and 27 patients with ulcerative colitis (UC) were tested by ELISA with cord factor purified from Mycobacterium tuberculosis H37Rv as the antigen. Twenty-three of the 27 patients with intestinal tuberculosis (85%) showed elevated values distinct from healthy controls. None of the patients with CD showed an elevation of antibody titers. Of the 27 patients with UC, 26 (96%) did not show any anti-cord factor antibody elevation. We conclude that this method is simple and results are reproducible. The results of our study justify undertaking the detection of anti-cord factor antibodies to diagnose intestinal tuberculosis.

Adult↗
PubMed1995

Immunochemical characterization of recombinant and native tropomyosins as a new allergen from the house dust mite, Dermatophagoides farinae.

BACKGROUND: Two predominant mite species, Dermatophagoides farinae and Dermatophagoides pteronyssinus, are responsible for the immediate hypersensitivity reaction. Although a large number of antigens and allergens was detected in a whole mite culture extract, only the major allergens of Der I and II groups have been extensively studied. Much information on other important allergens remains to be accumulated. METHODS: A new allergen complementary DNA (cDNA) clone was isolated from a D. farinae protein cDNA library. The expression product of the cDNA and native tropomyosin from D. farinae were purified, characterized, and evaluated. RESULTS: An amino acid sequence deduced from the cDNA clone revealed significant homology with tropomyosins conserved in a wide range of animals. The amino acid sequences of two fragments obtained by degradation of the purified protein with cyanogen bromide coincided completely with the corresponding portions of the deduced amino acid sequence. The native tropomyosin reacted with specific IgE in the 31 sera tested at a high frequency (80.6%), comparable to that of Der f I (90.3%) and Der f II (74.2%). CONCLUSIONS: The cloned cDNA encodes tropomyosin. The high binding response of specific IgE antibodies to recombinant and native tropomyosins demonstrates that mite tropomyosin is an additional important allergen in house dust mite.

Allergens↗
PubMed1995

Stimulation of phagocytosis and phagosome-lysosome fusion by glycosphingolipids from Sphingomonas paucimobilis.

Sphingomonas paucimobilis, a Gram-negative opportunistic pathogen, is actively phagocytosed by human peripheral polymorphonuclear leukocytes (PMN) in vitro. However, when live or killed cells were delipidated, the phagocytic rate was clearly decreased. Therefore, we have investigated the physiological role of membrane lipids in phagocytic processes. S. paucimobilis type strain 2395 produces four classes of acidic glycosphingolipids (GL-1, GL-2, GL-3, and GL-4) with the common components of glucuronic acid, 2-hydroxy myristic acid and d18:0 or d21:1 long-chain base. The effect of acidic glycosphingolipids on phagocytosis by PMN using killed Staphylococcus aureus cells coated with glucuronosyl ceramide (GL-1) or ceramide tetrahexoside (GL-4) was also examined. The rate of phagosome-lysosome fusion by PMN was determined by counting acridine orange-stained bacteria under a fluorescence microscope. Both phagocytosis and phagosome-lysosome fusion by PMN of glycosphingolipid-coated bacteria were stimulated markedly in a dose-dependent manner. It was noted that GL-1 or GL-4 stimulated phagosome-lysosome fusion dramatically, but synthetic lipid A did not. Superoxide anion release from PMN was enhanced significantly by the coating with synthetic lipid A at higher concentration, but only slightly with GL-1 or GL-4. Glucuronic acid was an inhibitor of phagocytosis of GL-1-coated S. aureus by PMN. The effect of acidic glycosphingolipids obtained from mammalian tissue on phagocytosis was also compared with that of bacterial glycosphingolipids. Ganglioside GM3 and sulfatide showed a marked stimulative activity for phagocytosis by PMN, while the neutral glycosphingolipids did not. Thus, bacterial acidic glycosphingolipid and mammalian acidic glycosphingolipid promote phagocytosis and phagosome-lysosome fusion by PMN.

Glycosphingolipids↗
PubMed1995

Necrotizing fasciitis in association with hyperimmunoglobulin E syndrome.

A case of necrotizing fasciitis in association with hyperimmunoglobulin E (HIE) syndrome is reported. The patient was a 17-year-old Japanese boy with a clinical history of recurrent skin and pulmonary infections and eczematoid dermatitis, markedly elevated serum levels of IgE, and coarse facies. He had a gangrenous swelling on the lower abdominal wall, and his general condition was poor with high fever. The involved site was accompanied by subcutaneous gas; the culture of the pus of the lesion grew anaerobes without mixed growth of Staphylococcus aureus. Exhaustive debridement of necrotic fascia, which extended much farther than the gangrenous area, and administration of antibiotics had a curative effect on the gangrenous soft tissue infection. To the best of the authors' knowledge, this is the first published case of necrotizing fasciitis in association with HIE syndrome.

Adolescent↗
PubMed1995

Enzyme-linked immunosorbent assay (ELISA) using a glycolipid antigen for the serodiagnosis of melioidosis.

The serodiagnosis of melioidosis is commonly performed with tests using protein or polysaccharide as antigen. However, due to the low sensitivity, specificity and difficulty in the preparation of the antigens, more simple, precise and reproducible diagnostic tests were required. A purified glycolipid antigen (GL) which is a specific lipid component of Burkholderia pseudomallei has been used in an ELISA. With this antigen, specific immunoglobulin G (IgG) was detected in 49 out of 50 melioidosis sera. IgG was also detected in 2 out of 185 (Japanese) and 16 out of 181 (Vietnamese) control sera. Thus, the sensitivity was 98.0%, and specificity was 98.9% and 91.1% in the Japanese and Vietnamese sera, respectively. When the ELISA and indirect haemagglutination (IHA) tests were combined, a sensitivity of 100% and specificity of 97.8% were achieved. The advantages of the glycolipid antigen are ease of preparation, stability, high sensitivity and specificity.

Antigens, Bacterial↗
PubMed1995

Successful treatment of Pneumocystis carinii Pneumonia in mice with benanomicin A (ME1451).

Benanomicin A (BNM-A) has antimycotic activities via binding to mannan in the cell walls of fungi. Anti-Pneumocystis carinii activity of the agent was examined in the P. carinii-infected BALB/c nu/nu female mouse model because P. carinii also possesses mannan in the membranes. The infected mice were treated with intraperitoneal injections of six doses of BNM-A (1, 2.5, 5, 10, 30, and 100 mg/kg of body weight), 4 mg of pentamidine isethionate per kg, 100 mg of sulfamethoxazole per kg combined with 20 mg of trimethoprim per kg (co-trimoxazole), or saline for 21 days. Each dosage group consisted of 10 mice. During treatment, five mice in the control group (saline) died, whereas 8 to 10 mice in all treatment groups survived. Almost the same efficacies were obtained for the groups treated with 5 mg or more and 10 mg or more of BNM-A per kg regarding the weight and number, respectively, of cysts found in the lungs as were obtained for the groups treated with pentamidine isethionate and co-trimoxazole. Overall, a dose of 10 mg of BNM-A per kg was effective against P. carinii pneumonia infection in the mice. Thus, BNM-A is a good candidate for a novel treatment for P. carinii pneumonia as a compound with a new mechanism of action against P. carinii.

Animals↗
PubMed1995

Immune complex transfer enzyme immunoassay that is more sensitive and specific than western blotting for detection of antibody immunoglobulin G to human immunodeficiency virus type 1 in serum with recombinant pol and gag proteins as antigens.

Antibody immunoglobulin G (IgG) to human immunodeficiency virus type 1 (HIV-1) in serum was detected by ultrasensitive enzyme immunoassays (immune complex transfer enzyme immunoassays) with recombinant reverse transcriptase (rRT), p17 (rp17) and p24 (rp24) of HIV-1 as antigens and beta-D-galactosidase from Escherichia coli as the label. The immune complex, comprising 2,4-dinitrophenyl-bovine serum albumin-recombinant protein conjugate, antibody IgG to HIV-1, and recombinant protein-beta-D-galactosidase conjugate, was trapped on polystyrene beads coated with affinity-purified (anti-2,4-dinitrophenyl group) IgG, eluted with epsilon N-2,4-dinitrophenyl-L-lysine, and transferred to polystyrene beads coated with affinity-purified (anti-human IgG gamma-chain) IgG. Bound beta-D-galactosidase activity was assayed by fluorometry. The assays were highly reproducible with no serious serum interference, and they were much more sensitive than Western immunoblotting for the corresponding antigens. Signals with rRT, rp17, and rp24 for asymptomatic carriers were at least 56,000-, 680-, and 22-fold higher, respectively, than those for seronegative individuals, and neither indeterminate nor false-positive results were observed, whereas some serum samples were false negative or false positive by Western blotting for p17 and/or p24 antigen. In some cases, seroconversion was detected earlier than by conventional methods. Therefore, these assays are suggested to be more useful than conventional methods not only for the confirmation of antibody IgGs to RT, p17, and p24 of HIV-1 in serum but also for the detection of seroconversion.

Antigen-Antibody Complex↗
PubMed1995

Measurement of human immunodeficiency virus type 1 p24 in serum by an ultrasensitive enzyme immunoassay, the two-site immune complex transfer enzyme immunoassay.

Human immunodeficiency virus type 1 (HIV-1) p24 antigen was measured by an ultrasensitive enzyme immunoassay (two-site immune complex transfer enzyme immunoassay). The antigen was reacted simultaneously with 2,4-dinitrophenyl-biotinyl-bovine serum albumin-anti-recombinant p24 (rp24) Fab' conjugate and anti-rp24 Fab'-beta-D-galactosidase conjugate. The complex that was formed, comprising the three components, was transferred from polystyrene beads coated with affinity-purified (anti-2,4-dinitrophenyl group) immunoglobulin G (IgG) to polystyrene beads coated with streptavidin. The detection limit of rp24 was 2.4 fg (0.1 amol) per assay or 0.24 pg/ml with as little as 10 microliters of serum. When sera were treated at low pH, p24 was detected in 34 (68%) of 50 serum samples from asymptomatic carriers, in 25 (86%) of 29 serum samples from patients with advanced HIV-1 infection, and in none of 117 serum samples from HIV-1-seronegative individuals. Levels of p24 in serum were inversely correlated to those of anti-HIV-1 p24 IgG, and the recovery of rp24 added to serum decreased to zero with increasing levels of anti-HIV-1 p24 IgG in serum. This sensitive method may be used as a powerful tool for investigating the disease.

Antigen-Antibody Complex↗
PubMed1995

A new nitric oxide (NO) releaser: spontaneous NO release from FK409.

The remarkable vasorelaxant and anti-platelet effects of FK409 have been reported to be due to nitric oxide (NO) release. The purpose of the present study is to investigate the spontaneous NO-releasing pathway of FK409 in aqueous solutions. 1H-NMR spectra of FK409 suggested that the compound underwent a time-dependent elimination of the hydrogen atom at alpha-position of the nitro moiety (at the 5-position) in weakly alkaline solutions. In addition, the degradation of FK409 monitored by HPLC showed a pH-dependency accelerating with an increase of pH. These results revealed that the first step in the degradation of FK409 might be the hydroxyl ion-dependent subtraction of the hydrogen atom at the 5-position. On the other hand, NO release from FK409 also exhibited a pH-dependency, and the velocity of NO liberation was markedly enhanced above pH 6. Furthermore, a linear relationship between the rate of FK409 degradation and that of NO formation was observed, indicating that the rate-limiting step for NO formation is the same as that for degradation. Thus, the rate-limiting process of NO formation from FK409 is due to the deprotonation reaction of the hydrogen atom at the 5-position by hydroxyl ions. The deprotonation process appears to be an essential step for both FK409 degradation and NO release. On the basis of the results, a possible kinetic scheme for NO release from FK409 is proposed.

Buffers↗
PubMed1995

[The efficacy of intravenous lidocaine on various types of neuropathic pain].

We examined the efficacy of systemic local anesthetics on various types of neuropathic pain in 89 patients. Lidocaine 1.5 mg.kg-1 was infused intravenously for one minute. Pain score (PS) by visual analogue scale (VAS, 0-10) was measured 1, 5, 15 and 35 min after the infusion. The efficacy of intravenous lidocaine was evaluated by PS which was lowest after infusion. PS decreased to less than 50 percent of pre-infusion value in more than 75 percent of cases of cancer pain, postherpetic neuralgia, trigeminal neuralgia, low back pain with signs of root pain or spinal canal stenosis, peripheral nerve injury and thalamic pain, in 50-75 percent of cases of herpetic neuralgia, and in less than 50 percent of cases of cervical spondylosis, spinal cord injury, reflex sympathetic dystrophy, causalgia and psychogenic pain. This study suggests that systemic local anesthetics is effective in neuropathy due to cancer pain, postherpetic neuralgia, trigeminal neuralgia, low back pain with signs of root pain or spinal canal stenosis, peripheral nerve injury and thalamic pain.

Aged↗
PubMed1995

High-molecular-size mite allergens with high carbohydrate content in mite extract containing mite feces of Dermatophagoides farinae.

A series of mite allergens with high carbohydrate content was fractionated from mite extract containing mite feces by ultrafiltration, and successive chromatography on Ultrogel AcA 54, Sepharose CL-6B, and DEAE Toyopearl 650S. The final fractions isolated were termed HM1-2-Eff, -0.1A, -0.1B, -0.3A, -0.3B, and -1M according to the eluted salt concentration. These six fractions were stained weakly with Coomassie Brilliant Blue but strongly with periodate-Schiff's reagent on SDS-PAGE. Their molecular weight were estimated to be 150-155 KD on Sepharose CL-6B. All of these six fractions provoked strong erythema in skin of mite-sensitive and asthmatic patients. HM1-2-Eff, -0.1A, -0.1B and -0.3B reacted with 73% of mite-sensitive patients' IgE by the nitrocellulose dot blotting. One ng/ml of 4 fractions (HM1-2-0.1A, 0.3A, 0.3B and -1M) released histamine from mite allergic patient's blood cells. HM1-2-0.3A induced proliferation of T cell from immunized mouse by mite extract containing mite feces (Dff).

Allergens↗
PubMed1995

[Clinical usefulness of urinary anti HIV antibody test--a large scale study from 11 institutes in Japan].

An enzyme immuno assay kit has been developed to detect anti-HIV antibody in urine. In order to examine the clinical utility of the kit, 1333 urine samples were assayed. These samples consisted of 233 urine samples from HIV infected patients, 472 samples from HIV uninfected patients including 203 samples from patients with urogenital diseases, and 628 samples from normal subjects. Anti-HIV antibodies were detected in all the urine samples from HIV infected patients, and the diagnostic sensitivity for HIV infection was 100% with no false negative cases. A variety of anti-HIV antibody titers were found in the urine samples from HIV infected patients. However, no significant differences were found in the distribution patterns of urinary anti-HIV antibody titers among AC, ARC and AIDS patients. False positives were determined in only five samples in 628 healthy subjects (0.8%), one in 19 patients with hepatitis (5.3%), one in 45 patients with hemophilia (2.2%) and two in 105 pregnant women (1.9%). The antibody titers of all the false positive samples in these groups were less than the cut-off index multiplied by two. However, relatively high positive rates were demonstrated in the samples from urogenital diseases (11.8%), diabetes mellitus (20.0%) and auto-immune diseases (7.3%). False positive results were found to be directly correlated to the protein concentration of urinary protein, especially the immunoglobulin concentration in urine. The assay system was also evaluated by various reproducibility tests performed by different operators at different laboratories. The test results were satisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1995

NCAM-associated polysialic acid on ciliary ganglion neurons is regulated by polysialytransferase levels and interaction with muscle.

NCAM in its high polysialic acid (PSA) form is expressed on chick hindlimb motoneurons during their growth, and then decreases at about the time that synaptogenesis is completed. In order to characterize this regulation at the cell and molecular level, the present studies use the chick ciliary ganglion (CG) system, which constitutes a homogeneous and developmentally synchronized population of motoneurons that can be used for in vitro studies. Levels of PSA in the CG were evaluated both by SDS-PAGE immunoblot analysis of total NCAM and by pulse radiolabeling of newly synthesized NCAM. Up- and downregulation of PSA expression on newly synthesized NCAM in the CG was found to be closely correlated with in vivo innervation and synaptogenesis, respectively. Moreover, the downregulation observed at synaptogenesis was prevented by in vivo blockade of neuromuscular activity with alpha-bungarotoxin. The developmental regulation of PSA expression was found to coincide precisely with an increase and decrease in levels of specific polysialyltransferase activity. By contrast, the expression of the VASE exon in NCAM, which in CNS is temporally correlated with PSA downregulation, was not expressed in the CG. Cocultures of CG neurons with myotubes were used to provide direct evidence that neuron-muscle interaction can cause a specific downregulation of both neuronal PSA and polysialyltransferase activity.

Animals↗
PubMed1995

Design and anti-HIV-1 activity of ribozymes that cleave HIV-1 LTR.

A hairpin ribozyme (HR112) and two hammerhead ribozymes (RZ115 and RZ119) containing a 5'C(UUCG)G3' loop were designed to cleave the long terminal repeat (LTR) of HIV-1. When the ribozyme catalyzed RNA cleavage reaction for a chemically synthesized 19 mer (LTR 19) was measured, the t 1/2 value of LTR 19 mediated by RZ115 was smaller than that of the RZ119 case. Moreover, the transformed CEM cells harboring the gene encoding these ribozymes were challenged with a HIV-1IIIB strain, two ribozymes, HR112 and RZ119 possessed strong anti-HIV-1 activity. However, the anti-HIV-1 activity displayed by RZ115 was weak. On the basis of secondary structure predictions of the RNA transcribed with the gene encoding ribozymes, the secondary structure of the transcribed RNA with RZ115 sequences was observed to be different from those with the other ribozymes. It has been demonstrated that the secondary structures of transcribed RNAs can possibly influence the anti-HIV-1 activity.

Antiviral Agents↗
PubMed1994

Nonsense mutations in the vpr gene of HIV-1 during in vitro virus passage and in HIV-1 carrier-derived peripheral blood mononuclear cells.

Long-term, persistent infection by HIV-1 is a prerequisite for the development of AIDS. However, little is known of the determinants required for HIV-1 to cause persistence. We have reported previously that persistent infection of a T cell line by a cytopathogenic strain of HIV-1 became increasingly likely with in vitro serial passage of the virus. DNA sequencing of the persistent strains revealed a nonsense mutation in the vpr gene in all isolates tested. Here, we report the development and use of a semi-quantitative PCR method to detect the vpr nonsense mutation within populations of virus. Our results show that vpr mutants also arise in cells during acute infection and increase progressively with serial passage of the virus. In addition, HIV-1-seropositive individuals were examined and found to carry the same vpr nonsense mutation at high frequency in virus-infected PBMC. These data are consistent with a mechanism of HIV-1 persistence in vivo and in vitro in which virus cytopathogenic potential is lost by the build up of nonsense mutations in vpr.

AIDS-Related Complex↗