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Biomedical subjects

T Kurata

Publications and source records attributed to T Kurata.

At least 217 records · Page 12Linked to original sources
PubMed1993

Amplification and detection of a single molecule of human immunodeficiency virus RNA.

Detection of plasma viremia in human immunodeficiency virus type 1 (HIV-1)-infected people is indispensable for the diagnosis of seronegative infection as well as for the evaluation of virus activities in vivo. The direct detection of HIV-1 RNA in circulation has been performed by means of reverse transcription followed by polymerase chain reaction (RT-PCR). As an attempt to establish a highly sensitive assay, we evaluated the effects of two-step amplification with nested primers and double priming of reverse transcription on the sensitivity of RT-PCR. The sensitivity of two-step amplification was 100 times higher than that of one-step amplification. The double priming of reverse transcription further increased the sensitivity of the following two-step amplification 100 times, which appeared to be enough to detect HIV-1 RNA from as little as a 2.2 x 10(-4) TCID50 unit equivalent of culture supernatant of HIV-1-infected cells and a single molecule of HIV-1 gag complementary RNA synthesized by in vitro transcription. By use of this most sensitive assay, we successfully detected HIV-1 RNA in serum or plasma from all 22 patients with acquired immune deficiency syndrome (AIDS) or AIDS-related complex (ARC) and 13 out of 14 untreated asymptomatic carriers. Of 43 asymptomatic carriers under the treatment with interferon-alpha or azidothymidine, 17 cases showed negative results, indicating that the virus activity was suppressed by the therapeutics. We also noted the inhibitory effect of heparin on RT-PCR.

Base Sequence↗
PubMed1993

Structure of 85 kDa subunit of human phosphatidylinositol 3-kinase analyzed by using monoclonal antibodies.

An 85 kDa subunit (p85 alpha) of phosphatidylinositol 3-kinase (PI-3K) has one SH3 and two SH2 regions [SH2(N) and SH2(C)], which direct protein-protein interaction. We have established eighteen hybridomas producing monoclonal antibodies against p85 alpha to study the structure-function relationship of this protein. Epitope mapping using a series of deletion mutants expressed in E. coli showed that the monoclonal antibodies bound to at least 5 distinct epitope regions, which were well dispersed on p85 alpha except for its carboxyl-terminus. Monoclonal antibodies against amino-terminal regions and polyclonal antibodies against carboxyl-terminal regions immunoprecipitated p85 alpha expressed in human cells and in E. coli. On the other hand, monoclonal antibodies against the central part of p85 alpha failed to immunoprecipitate p85 alpha efficiently; however, they could immunoprecipitate p85 alpha mutants with deletion of either the amino- or the carboxyl-terminal region. Similar results were obtained by immunocytochemistry using confocal microscopy. These results suggested that steric hindrance prevents binding of monoclonal antibodies to the central part of p85 alpha where SH2(N) is located. The SH2(N) may have a distinct function from SH2(C), which is located at the carboxyl-terminal region and has been shown to mediate the binding of PI-3K to activated growth factor receptors.

Animals↗
PubMed1993

Isolation of human herpesvirus 7 from a child with symptoms mimicking chronic Epstein-Barr virus infection.

Human herpesvirus-7 (HHV-7), which is a newly identified human herpesvirus with an unknown pathologic role, was isolated from a 5-year-old boy suffering from fever, hepatosplenomegaly and pancytopenia. Although the clinical course was similar to that of chronic active Epstein-Barr virus infection, no viruses other than HHV-7 were isolated. This finding raises the possibility that HHV-7 played a pathogenic role in the present patient.

Child, Preschool↗
PubMed1993

Varicella-zoster virus replication site in internal organs of an otherwise healthy child with varicella and sudden death.

Pathological findings of an otherwise healthy 17 month old boy who was exposed to Varicella-zoster virus (VZV) in his family and unexpectedly died 3 days after onset of varicella are reported. They showed a disseminated VZV infection with involvement of skin, lung, liver, spleen, gastrointestinal tract and other organs where VZV antigen was detected by the enzyme-immunoassay with monoclonal antibodies to VZV. Since the subject was the full-term product of an uncomplicated pregnancy, who grew and developed normally, and had no symptoms or laboratory findings suggestive of immunodeficiency until his death, these findings suggest that many organs are involved as major internal sites of viral replication before or during infection of skin with VZV in the immunocompetent host.

Antibodies, Monoclonal↗
PubMed1993

[Detection and identification of mycobacterial DNA with sputa and AIDS samples by nested-polymerase chain reaction (nested-PCR)].

We have demonstrated the nested-polymerase chain reaction (nested-PCR) assay detected from 14 mycobacterial species. We have further demonstrated the species specific restriction sites within amplified dnaJ gene, which allowed us to differentiate the mycobacterial DNA by combination of the PCR with the restriction fragment length polymorphism (PCR-RFLP). Nested-PCR-RFLP was used to detect and identified mycobacterial DNA in the sputa samples and HIV related samples. The target DNA was a 196-base pair segment of dnaJ gene. Of 68 sputum samples tested, 7 were smear positive for acid-fast bacilli and culture. The 7 samples were also identified with Mycobacterium tuberculosis by PCR-RFLP. We tested 69 HIV related samples (19 frozen samples, 22 paraffin embedded samples and 28 lymphocyte from HIV infected people). Of 38 samples were positive for nested-PCR, 8 M. tuberculosis complex, 7 M. avium, 8 M. intracellulare, and 16 others were detected by PCR-RFLP. The PCR method is useful for the rapid diagnosis of mycobacterial infection.

AIDS-Related Opportunistic Infections↗
PubMed1993

Mechanistic study of inhibition of levofloxacin absorption by aluminum hydroxide.

The mechanisms of reduction in absorption of levofloxacin (LVFX) by coadministration of aluminum hydroxide were studied. The partition coefficient of LVFX (0.1 mM) between chloroform and phosphate buffer (pH 5.0) was reduced by 60 to 70% with the addition of metal ions such as Cu2+, Al3+, and Fe2+ (0.8 mM), which indicated the formation of LVFX-metal ion chelates. However, there was no significant difference in absorption from rat intestine between the synthetic LVFX-Al3+ (1:1) chelate (6.75 mM) and LVFX (6.75 mM) in an in situ recirculation experiment. On the other hand, Al(NO3)3 (1.5 mM) significantly inhibited the absorption of LVFX (1.5 mM) by 20% of the control in the in situ ligated loop experiment, in which partial precipitation of aluminum hydroxide was observed in the dosing solution. Data for adsorption of LVFX and ofloxacin (OFLX) from aqueous solution by aluminum hydroxide were shown to fit Langmuir plots, and the adsorptive capacities (rmax) and the K values were 7.0 mg/g and 1.77 x 10(4) M-1 for LVFX and 7.4 mg/g and 1.42 x 10(4) M-1 for OFLX, respectively. The rate of adsorption of several quinolones (50 microM) onto aluminum hydroxide (2.5 mg/ml) followed the order norfloxacin (NFLX) (72.0%) > enoxacin (ENX) (61.0%) > OFLX (47.2%) approximately LVFX (48.1%). The elution rate of adsorbed quinolones with water followed the rank order LVFX (17.9%) approximately OFLX (20.9%) approximately ENX (18.3%) > NFLX (11.9%). These results strongly suggest that adsorption of quinolones by aluminum hydroxide reprecipitated in the small intestine would play an important role in the reduced bioavailability of quinolones after coadministration with aluminum-containing antacids.

Aluminum Hydroxide↗
PubMed1993

Both the SH2 and SH3 domains of human CRK protein are required for neuronal differentiation of PC12 cells.

Human CRK protein is a homolog of the chicken v-crk oncogene product and consists mostly of src homology region 2 (SH2) and SH3, which are shared by many proteins, in particular those involved in signal transduction. SH2 has been shown to bind specifically to phosphotyrosine-containing peptides. We report here that both SH2 and SH3 are required for signaling from CRK protein. Microinjection of the CRK protein induced neurite formation of rat pheochromocytoma cell line PC12. This activity was abolished by mutation of the CRK protein in either SH2 or SH3. The neuronal differentiation induced by the CRK protein was blocked by an excess amount of peptides containing CRK SH3. Moreover, we identified three proteins, of 118, 125, and 136 kDa, which bound specifically to CRK SH3. The CRK-induced neuronal differentiation was also suppressed by monoclonal antibodies against either CRK SH2 or p21ras. These results suggest that both SH2 and SH3 of the CRK protein mediate specific protein-protein binding and that the resulting multimolecular complex generates a signal for neurite differentiation through activation of p21ras.

Amino Acid Sequence↗
PubMed1993

Pathologic features of acquired immunodeficiency-like syndrome in cats experimentally infected with feline immunodeficiency virus.

Five specific pathogen free cats were inoculated with feline immunodeficiency virus (FIV) isolated in Japan to observe changes toward development of acquired immunodeficiency syndrome (AIDS)-like disease. All inoculated cats had lymphadenopathy and mild respiratory disease shortly after inoculation. Following the initial acute phase lasting for more than 40 weeks, the clinical signs gradually diminished in three animals, and the asymptomatic carrier (AC) stage was observed at 45 (1 cat) and 70 (2 cats) weeks postinoculation (p.i.). Two of the three cats developed respiratory signs and diarrhea at 105 or 106 weeks p.i. One cat died at 121 weeks p.i. with severe wasting, with necropsy findings consistent with AIDS-related complex (ARC). The others were surviving at 150 weeks p.i. with mild clinical signs or asymptomatic. Another group of two cats developed more severe illness without the AC phase. One died at 48 weeks p.i. with the ARC illness. The other cat developed marked emaciation with diarrhea at 75 weeks p.i., and died at 100 weeks p.i. with a histologic diagnosis suggestive of terminal immunodeficiency. Histologically, the lymph nodes showed serial changes toward the terminal illness, from follicular hyperplasia at the acute phase to the lymphoid depletion at the ARC and AIDS-like terminal stages. The FIV antigen was demonstrated in the lymph nodes. The virus was isolated from peripheral blood mononuclear cells of all the inoculated animals. These data demonstrated possible etiologic association of FIV with development of AIDS-like disorders in the cat.

Animals↗
PubMed1993

Application of indirect immunofluorescence microscopy to colony identification of Pseudomonas pseudomallei.

Indirect immunofluorescence microscopy was used as a colony identification method of Pseudomonas pseudomallei isolates. The antisera against lipopolysaccharide and protein fractions of P. pseudomallei were prepared in guinea pigs and rabbits. With these antisera and fluorescence-labelled anti-guinea pig IgG and anti-rabbit IgG prepared in sheep (goat), indirect immunofluorescence microscopy was conducted on the colonies of P. pseudomallei and other species of bacteria. The overall results indicated that this method is efficient, rapid and specific for identification of P. pseudomallei colonies from clinical specimens.

Animals↗
PubMed1993

[Aggressive diffuse lymphoma with malignant pleural effusion expressing c-erbB-2 (neu) oncogene products].

An 83-year-old male was admitted with a right pleural effusion and generalized lymphadenopathy. Serum LDH level was elevated to 801 IU/L, and the pathological diagnosis from inguinal lymph node needle biopsy was malignant lymphoma (ML) of diffuse, large cell, non-cleaved type, according to the working formulation. The surface phenotypes of the malignant cells from the pleural effusion were analyzed by a fluorescent-activated cell sorter with a panel of monoclonal antibodies (MAbs). The ML cells coexpressed antigens detected by MAbs CD10 (CALLA), CD19, CD20, CD22, CD24, CD38, Ia, c-neu and surface immunoglobulin G kappa. A high expression of NRAS p21 was also detected by cytoplasmic immunofluorescence technique. The patient died 19 days later despite a combination of chemotherapy and intensive supportive therapy. From these findings it seems that c-neu may be a prognostic indicator not only for breast cancers but also for lymphoproliferative disorders. Further accumulation of such cases is needed.

Aged↗
PubMed1993

[A comparison of lymphocyte stimulation test results and challenge test results in 19 cases of antituberculous drug-induced allergy].

We clinically investigated 19 cases of antituberculous drug-induced allergy. The results of the challenge tests were positive in 30 out of the 55 drugs tested. The results of the lymphocyte stimulation tests were positive in 19 out of the 55 drugs tested. In 84.2% of the cases with positive lymphocyte stimulation test findings, the challenge test was also positive. It can be concluded from these results that the lymphocyte stimulation test may be useful in the detection of the causes of drug induced allergies in patients undergoing drug therapy for tuberculosis.

Adult↗
PubMed1992

Cross-protection against influenza virus infection afforded by trivalent inactivated vaccines inoculated intranasally with cholera toxin B subunit.

Cross-protection against influenza virus infection was examined in mice, immunized intranasally with a nasal site-restricted volume of inactivated vaccines together with cholera toxin B subunit (CTB) as an adjuvant. The mice were challenged with either a small or a large volume of mouse-adapted virus suspension, each of which gave virgin mice either a predominant upper or lower respiratory tract infection. A single dose of a monovalent influenza A H3N2 virus vaccine with CTB provided complete cross-protection against the small-volume challenge with a drift virus within the same subtype, but a slight cross-protection against the large-volume challenge. A second dose of another drift virus vaccine increased the efficacy of cross-protection against the large-volume challenge. Similar cross-protection against H1N1, H3N2, or B type drift virus challenge was provided in the mice having received a primary dose of a mixture of H1N1, H3N2, and B virus vaccines with CTB and a second dose of another trivalent vaccine. The degree of cross-protection against the small- and the large-volume infection paralleled mainly the amount of cross-reacting IgA antibodies to challenge virus hemagglutinin in the nasal wash and that of cross-reacting IgG antibodies in the bronchoalveolar wash, respectively. On the other hand, in mice immunized subcutaneously with the trivalent vaccines having no cross-reacting IgA antibodies, the efficacy of cross-protection was not so high as that of nasal vaccination. These results suggest that the nasal inoculation of trivalent vaccines with CTB provides cross-protection against a broader range of viruses than does the current parenteral vaccination.

Administration, Intranasal↗
PubMed1992

Superior cross-protective effect of nasal vaccination to subcutaneous inoculation with influenza hemagglutinin vaccine.

Intranasal (i.n.) vs. subcutaneous (s.c.) administration of influenza hemagglutinin (HA) vaccine was systematically compared in BALB/c mice. Mice were immunized with different vaccines, together with cholera toxin B subunit as an adjuvant, and 4 weeks later were challenged with either a small (2 microliters) or a large (20 microliters) volume of mouse-adapted A/Guizhou-X (H3N2) virus, each of which gave virgin mice either a nasal or a lung predominant infection. Both i.n. and s.c. inoculations of A/Guizhou-X vaccine conferred almost complete protection against both challenges, i.n. inoculation of A/Fukuoka (H3N2) or A/Sichuan (H3N2) vaccine conferred almost complete cross-protection against 2-microliters challenge and a partial cross-protection against 20-microliters challenge, whereas the s.c. inoculation conferred no cross-protection against 2-microliters challenge with a partial cross-protection against 20-microliters challenge. Moreover, i.n. immunization of PR8 (H1N1) vaccine gave a slight cross-protection against 2-microliters challenge, while the s.c. inoculation did not. The degree of protection was easily improved by i.n. inoculation of higher doses of vaccine, but not by the s.c. inoculation. In parallel with the protection, the i.n. vaccination produced a high level of cross-reacting IgA and IgG antibody to A/Guizhou-X HA in nasal and broncho-alveolar washes, while the s.c. vaccination produced the cross-reacting IgG antibody alone. Thus, i.n. inoculation with inactivated vaccines, which induces cross-reacting anti-HA IgA antibody as well as IgG antibody, is more effective than s.c. vaccination for providing cross-protection against drift viruses.

Administration, Intranasal↗
PubMed1992

Detection of capsid antigen of human papillomavirus (HPV) in benign lesions of female genital tract using anti-HPV monoclonal antibody.

We established a murine monoclonal antibody (K1H8) to human papillomavirus (HPV) using alkaline-disrupted virions of HPV type 1 (HPV-1) as the immunogen. K1H8 recognized a 57 kD capsid protein of HPV-1 and detected the antigen in paraffin sections of formalin-fixed tissue. With K1H8, we examined immunohistochemically 68 biopsy specimens obtained from the female genital tract. The specimens were histologically condyloma acuminatum or koilocytotic lesions with or without dysplasia and each specimen was found to harbour a single type of genital HPV, such as types 6, 11, 16, 18, 31, 33, 42, 51, 52, 56, and 58, by Southern blot hybridization analysis. The antigen was localized in the nuclei and occasionally in the cytoplasm of squamous cells showing koilocytotic changes. Eighty-four per cent of the specimens (57 cases) showed positivity for the antigen, indicating that K1H8 is a broadly-reactive antibody to various genital HPVs. The results suggest that benign mucosal lesions of the female genital tract are more frequently associated with viral production and are a potential source of transmission.

Animals↗
PubMed1992

Identification of epitopes associated with different biological activities on the glycoprotein of vesicular stomatitis virus by use of monoclonal antibodies.

Thirteen monoclonal antibodies (MAbs) to the glycoprotein (G) of vesicular stomatitis virus (VSV) serotype Indiana were prepared and examined for their effects on various biological activities of VSV, including in vitro infection, hemagglutination, adsorption to cells, and mediation of cell fusion. Competitive binding assays with these MAbs revealed the presence of at least seven distinct antigenic determinants (epitopes) on the G protein. In some cases, overlappings among epitopes to various degrees were observed as partial inhibition or binding enhancement. The MAbs to all the epitopes but one (epitopes 1-6) reacted with the denatured G protein in a Western immunoblot analysis. Four of the epitopes (epitopes 2, 4, 5, and 7) were involved in neutralization and two (epitopes 1 and 2) in hemagglutination inhibition. None of the MAbs inhibited the adsorption of radiolabeled VSV to BHK-21 cells; the MAbs to epitope 2 slightly enhanced the virus adsorption. All neutralization epitopes except epitope 2 (epitopes 4, 5, and 7) were associated with inhibition of VSV-mediated cell fusion. These results show a direct spatial relationship between the epitopes recognized by the MAbs and functional sites on G protein and further insights into the structure and function of G protein.

Adsorption↗
PubMed1992

Localization of herpes simplex virus type 1 in sebaceous glands of mice.

The distribution of HSV-1 during the development of zosteriform skin lesions in SCID mice was analyzed by immunofluorescence and electron microscopy. The virus initially appeared within certain keratinocytes, sometimes surrounded by keratinocytes whose surfaces were also positive for the antigens, in the lower epidermal layers including the hair follicles, and then extended upward to the entire epidermis and downward to the sebaceous glands 1-2 days later, when no macroscopic skin lesion was seen. The affected epidermal cells subsequently degenerated and lost their viral antigens within a day, when the zosteriform lesion then became evident. This was followed by a degeneration of the dermis. The sebaceous glands eventually degenerated in 10 days, but some glands in the necrotic skin areas preferentially retained HSV-1. The horizontal spread of the virus in the epidermis beyond the first invaded dermatome occurred much later. In mice passively immunized with specific immune serum, viral antigens were observed even 20 days after the infection in sebaceous glands in necrotized areas. Therefore, HSV-1 appears to spread first via the extracellular fluid among the keratinocytes after being shed from nerve endings, and then produces a successive degeneration of the affected keratinocytes which may prevent any further extension of horizontal viral spread. The pilosebaceous apparatus is possibly acting as a site not only for the replication of HSV-1 with a delayed cytopathic effect, but also as an area that is temporarily sheltered from host defense mechanisms.

Animals↗