PubMed Health⌕ Search

Biomedical subjects

J Imai

Publications and source records attributed to J Imai.

At least 55 records · Page 3Linked to original sources
PubMed1992

Rapid, sensitive, specific, and quantitative detection of human T-cell leukemia virus type 1 sequence in peripheral blood mononuclear cells by an improved polymerase chain reaction method with nested primers.

Improving on the nested double polymerase chain reaction (PCR) described previously, we have developed a new two-step PCR (TS-PCR) method for detecting more specifically the human T-cell leukemia virus type 1 (HTLV-1) proviral sequences in peripheral blood mononuclear cells (PBMC). In our TS-PCR method, the point of modification is to use optimal concentrations of primers in the first amplification step in the range of 0.01-0.025 microM. This increases sensitivity and specificity enough to detect from 1 to 10(5) copies of template DNA without radioisotopes. This method is rapid because of completion in 1 day and is also applicable for quantitative detection of clinical specimens. The data show that the quantitative detection of HTLV-1 proviral sequences by this method correlates with the anti-HTLV-1 antibody titers from serologic analysis of seropositive healthy carriers. Moreover, the TS-PCR method using each specific primer was also attempted for successful detection of other viral genomes; therefore, the principle of this method is widely suitable for routine detection of genomes in the basic and clinical microbiological fields.

Base Sequence↗
PubMed1992

Human sera from varicella-zoster virus (VZV) infections cross-react with human T cell leukaemia virus type 1 (HTLV-1): common epitopes in VZV gene 22 protein and HTLV-1 p19 gag protein.

Twenty-nine of 100 sera from patients recently infected with varicella-zoster virus (VZV) were found to cross-react with human T cell leukaemia virus type 1 (HTLV-1) antigen in the particle agglutination (PA) assay using HTLV-1 antigen-coated gelatin particles. Anti-VZV IgM antibodies were shown to be responsible for this cross-reactivity. Western blot analysis revealed that PA-positive anti-VZV sera reacted with the HTLV-1 gag p19 protein in HTLV-1-infected cells and recombinant p19 protein produced in Escherichia coli. By using a truncated p19, the cross-reactive region was located to the C-terminal 17 amino acids of p19. One oligopeptide derived from the C terminus, PQIPPPYVEPT (amino acids 115 to 125), was capable of inhibiting PA, suggesting that this peptide carries the cross-reactive epitope. A homologous sequence was found in the VZV gene 22 protein by database analysis, and the oligopeptide TNIPPPLALLR (amino acids 1330 to 1340) had the ability to inhibit PA. These findings suggest that some IgM antibodies against the VZV gene 22 protein produced in the early phase of VZV infection are cross-reactive with the HTLV-1 gag p19 protein because they recognize an antigenic determinant containing an IPPP tetrapeptide.

Agglutination Tests↗
PubMed1992

Kynostatin (KNI)-227 and -272, highly potent anti-HIV agents: conformationally constrained tripeptide inhibitors of HIV protease containing allophenylnorstatine.

Selective and potent HIV protease inhibitors containing allophenylnorstatine [Apns; (2S, 3S)-3-amino-2-hydroxy-4-phenylbutyric acid] as a transition-state mimic were designed and synthesized. Among them, conformationally constrained tripeptide derivatives, kynostatin (KNI)-227 and -272 (Fig. 1), exhibited highly potent antiviral activities against a wide spectrum of HIV isolates. Ready availability due to the simple synthetic procedure and the excellent antiviral properties indicate that KNI-227 and KNI-272 are promising candidates as selective anti-AIDS drugs.

Antiviral Agents↗
PubMed1992

[Bacterial contamination of infant urine samples obtained from filter papers used in neuroblastoma-screening tests. (6) Protective effects of preaddition of chlorhexidine digluconate in filter papers or containers for urine on bacterial break-down of creatinine, vanillylmandelic acid and homovanillic acid].

The effects of chlorhexidine digluconate preadded to urine samples for a neuroblastoma-screening test in preventing the break-down of creatinine (Cre), vanillylmandelic acid (VMA), and homovanillic acid (HVA) by creatinine-cleaving bacteria and the influence of the added disinfectant on the HPLC determination of urinary Cre, VMA, vanillillactic acid (VLA) and HVA. Laboratory or field experiments showed that preadded disinfectant (0.02% volume) nearly completely inhibited the growth of the bacteria and satisfactorily protected urinary Cre, VMA, and HVA from bacterial decomposition. Chlorhexidine digluconate was comparable to benzalkonium chloride in its inhibitory effects on the growth and activities of creatinine-cleaving bacteria. Unlike benzalkonium chloride, chlorhexidine digluconate added to urine samples gave no troubles in subsequent analytical processes. Addition of the disinfectant (0.02% volume) to standard Cre, VMA, VLA, and HVA solution did not affect retention times and sensitivities in HPLC analyses. To estimate influences of the added disinfectant on the serial HPLC determinations of VMA, VLA, and HVA on a large number of urine samples (40, 80, 120, 160, 200, or 5, 500), HPLC analyses were performed on standard VMA, VLA, and HVA solution with repeated injection of the disinfectant in great amounts into a column. The results showed no appreciable changes in the retention times and sensitivities of VMA, VLA, and HVA, and almost complete elution of the disinfectant retained on the column were possible with water-methanol (1:1, 2:8) or methanol washing.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1991

Improvement of gelatin particle agglutination test for detection of anti-HTLV-I antibody.

Partial modifications of antigen components were made to improve the gelatin particle agglutination (PA) test for the detection of antibodies against human T cell leukemia virus type-I. Envelope glycoproteins prepared by lentil lectin affinity chromatography were further added to the purified viral antigens to be coated on the gelatin particles. Comparative studies with a conventional PA test kit (Serodia ATLA) and indirect immunofluorescence assay showed that the specificity and sensitivity of the new PA test were increased and that abnormal agglutination such as the prozone phenomenon was abolished by this improvement.

Agglutination Tests↗
PubMed1991

Rational design and synthesis of a novel class of active site-targeted HIV protease inhibitors containing a hydroxymethylcarbonyl isostere. Use of phenylnorstatine or allophenylnorstatine as a transition-state mimic.

A novel class of HIV-1 protease inhibitors containing a hydroxymethylcarbonyl (HMC) isostere were designed from the substrate transition state and synthesized. Phenylnorstatine [Pns; (2R,3S)-3-amino-2-hydroxy-4-phenylbutyric acid] and the 2S diastereomer, (2S,3S)-3-amino-2-hydroxy-4-phenylbutyric acid, named allophenylnorstatine (Apns) were effective transition-state mimics, and incorporation of Pns-Pro or Apns-Pro at the P1-P1' site gave potent and specific HIV-1 protease inhibitors. In the inhibitory assays, the chemically synthesized [Ala67,95] HIV-1 protease was used.

Amino Acid Sequence↗
PubMed1991

KNI-102, a novel tripeptide HIV protease inhibitor containing allophenylnorstatine as a transition-state mimic.

HIV-1 protease inhibitors containing allophenylnorstatine [Apns; (2S,3S)-3-amino-2-hydroxy-4-phenylbutyric acid]-Pro (syn diastereomer) as a transition-state mimic were established to be potent and highly selective. Z-Asn-Apns-Pro-NHBut (KNI-102) is the only tripeptide exhibiting substantial anti-HIV activity and may be of minimum size for potent, selective inhibition of HIV protease. Ready availability due to its simple chemical structure and stability should make it valuable for studies of the development of metabolically stable anti-AIDS drugs.

Amino Acid Sequence↗
PubMed1990

A potent antibacterial protein in royal jelly. Purification and determination of the primary structure of royalisin.

A new potent antibacterial protein, for which we propose the name royalisin, was found in royal jelly of the honeybee Apis mellifera L. and purified to homogeneity for the first time by acid extraction, gel filtration, and reverse-phase high pressure liquid chromatography. The primary structure of royalisin was determined to consist of 51 residues, with three intramolecular disulfide linkages, having a calculated molecular mass of 5523 Da. Royalisin is an amphipathic protein, with the C-terminal half of the molecule being rich in charged amino acids; and it showed extensive sequence homology to two other antibacterial proteins, sapecin from embryonic Sarcophaga peregrina cells and phormicins from Phormia terranovae larvae. Royalisin was found to have potent antibacterial activity against Gram-positive bacteria at low concentrations, but not against Gram-negative bacteria. Royalisin may be involved in a defense system active against bacterial invasion of the honeybee.

Amino Acid Sequence↗
PubMed1990

Geographical distribution of subjects seropositive for human T-cell leukemia virus type 1 in Papua New Guinea.

Of 1471 sera collected from 1986 to 1989 in Papua New Guinea (PNG), 2.2% were found to be positive for anti-HTLV-1 antibody by successive particle agglutination and immunofluorescence tests. The seropositive rate varied in different provinces and was higher in the coastal areas of the main island and in neighboring small islands than in the highlands of PNG. The frequency of HTLV-1 infection of children was higher, but the age-dependent increase in antibody positivity, generally observed in other HTLV-1 endemic areas of the world, was not clear in PNG. No difference was observed in antibody prevalence in males and females in this study.

Adolescent↗
PubMed1990

[Therapeutic evaluation of combination therapy using C-425, human native immunoglobulin liquid preparation for i.v. administration, with antibiotics in severe infections in the field of surgery].

In a nationwide study conducted in 11 surgical institutions of C-425, a newly developed human native immunoglobulin liquid preparation for intravenous injection, was combined with conventional antibiotic treatment to investigate the efficacy and safety. A total of 47 patients with severe infections which had not symptomatically responded to 3-day or longer treatment with any antibiotics was included. Doctors in charge judged the efficacy of C-425 to be "excellent" in 3 patients, "good" in 13, "fair" in 15, and "poor" in 4. Thus, a total of 16 patients (45.7%) was judged to have responded to C-425 when the "excellent" and "good" responses were combined. The number responding was 31 (88.6%) when the "fair" cases were also included. Excluding 31 patients who did not meet the Committee's criteria, the Committee judged the efficacy of C-425 in a total of 16 patients; the efficacy was "excellent" in 2 patients, "good" in 4, "fair" in 9, and "poor" in 1. The number of responding patients was 6 (37.5%) of the 16 when the "excellent" and "good" cases were combined, and 15 (93.8%) when the "fair" cases were added. Bacteriological assessment was conducted in a total of 9 patients. Causative bacteria were eradicated in 3 patients, decreased in number in 1, replaced in 2, and persisted in 3. Thus, bacteriological efficacy was observed in 6 of the 9 patients (66.7%). Neither adverse reactions nor drug-related laboratory abnormalities were observed in the 47 patients.

Adult↗
PubMed1990

Studies on the synthesis of compounds related to adenosine-3',5'-cyclic phosphate. VI. Synthesis and cardiac effects of N6,N6,2'-O-trialkyl-, N6,2'-O-dialkyl-, and 2'-O-alkyladenosine-3',5'-cyclic phosphates.

The alkylation of adenosine-3',5'-cyclic phosphate (cAMP, 1) with alkyl bromides was investigated and various new alkylated cAMP derivatives, N6,N6,2'-O-trialkyl cAMPs (2), N6,2'-O-dialkyl cAMPs (3) and 2'-O-alkyl cAMPs (4), were prepared by a one step reaction without the introduction of a protecting group into 1. Compounds (2) were synthesized from 1 by treatment with alkyl bromides in the presence of NaH or potassium tert-butoxide in dimethyl sulfoxide. Compounds (3) were also synthesized from 1 under conditions similar to those of the synthesis of 2 except for the use of MeONa as a base. Compounds (4) were prepared from 1 by treatment with alkyl bromides in the presence of 18-crown-6 in dioxane-aqueous KOH solution. N6,2'-O-Dibenzyl cAMP (3e) was obtained from 1 by the same method as the preparation of 4. These new alkylated derivatives were evaluated for cardiotonic activity in vitro. Some of them showed weak positive inotropic effects and strong negative chronotropic effects. Thus, the presence of the 2'-hydroxyl group seemed to be essential for the appearance of potent positive inotropic activity caused by cAMP derivatives.

Animals↗
PubMed1990

[The development of a highly sensitive IgE immunoradiometric assay using monoclonal antibodies].

We have developed two-site immunoradiometric assay (IRMA) for quantitation of human serum IgE, using two different anti-IgE monoclonal antibodies which recognize different epitopes on IgE molecule. We obtained 25 different monoclonal antibodies classified seven groups, and then two different monoclonal antibodies were selected for bead coater and tracer after checking the titer and specificity of each antibody. IgE IRMA we developed here showed good performance in terms of specificity, sensitivity and reproducibility. No cross-reactivity to IgG, IgM and albumin in the level of normal range was observed. The sensitivity for IgE assay was 0.6 x 10(-3) IU/tube and measurable range was 0.01-20.0 IU/tube (0.5-10(3) IU/ml). Coefficient of variations of Intra assay were 2.2-4.3% and average recovery yield was 92.5-108%. Good correlations with Phadebas IgE PRIST and Pharmacia IgE RIA were obtained i.e., y = 1.12x-0.19 (r = 0.96) and y = 0.97x-5.9 (r = 9.7), respectively. These results indicate that the assay system will contribute much to the routine diagnosis for atopic allergy disease and parasitic infections.

Antibodies, Monoclonal↗
PubMed1990

An easy and safe modified method of endoscopic balloon dilation for postgastrectomy anastomotic stricture.

An easy and safe modified method for endoscopic balloon dilation was performed 24 times for 16 patients who had undergone subtotal gastrectomy without any ensuing complications. The balloon dilator was simply attached to the ultraslender forward-viewing fiberscope just above the flexible portion. The balloon dilator can be easily placed into the stricture by advancing the fiberscope into the duodenum under direct vision. The present technique is particularly useful for the tortuous stricture of B-I anastomosis after a surgical procedure for carcinoma of the stomach, as opposed to using the conventional bougie or previous balloon techniques. This method may also be useful for other kinds of complicated stricture of the upper or lower part of the gastrointestinal tract.

Adult↗
PubMed1989

Patterns of migration indicate sexual transmission of HTLV-I infection in non-pregnant women in Papua New Guinea.

The prevalence of infection with human T-cell leukaemia virus (HTLV-I) was studied in Madang Province on the north coast of Papua New Guinea. Serum specimens collected from non-pregnant women in 17 villages were tested for anti-HTLV-I by gelatin particle agglutination screening and confirmed by immunofluorescence and Western blotting. Overall, 13.9% of subjects were antibody-positive, with the prevalence of antibodies varying from less than 10% to 30% in villages situated less than 10 km apart. Two groups of migrant women were identified, and in both a parity-related increase in antibody prevalence which occurred only after marriage suggested that the predominant mode of transmission in migrant women was sexual. There was no parity-associated increase in anti-HTLV-I in indigenous women, and in contrast to migrant women, nulliparous indigenous women had a high prevalence of antibody (16.8% vs. 0%; p = 0.005). Vertical transmission cannot be excluded in indigenous women. No correlation was detected between the prevalence of anti-HTLV-I and a variety of indices of malarial infection.

Emigration and Immigration↗
PubMed1989

Performance certification of gelatin particle agglutination assay for anti-HTLV-1 antibody: inconclusive positive results.

In order to test the performance of particle agglutination assay (PA), 800 preselected PA-positive sera at 8 blood centers in the Kyushu area were tested in various assays. Most blood centers should improve their PA technique, since a third of the samples were PA-negative in our hands. A third of our PA high-titer sera were negative in indirect immunofluorescence and enzyme immunoassay, the results of which were consistent with each other. Western blots did not detect every positive serum. PA inhibition positivity was not consistent with PA titer. Most IgM antibody-positive sera also contained IgG antibody. PA should be used in combination with other methods before notifying the results to positive testees.

Agglutination Tests↗
PubMed1989

Alkylated cAMP derivatives: selective synthesis and biological activities.

Many alkylated cAMPs have been prepared and tested for their antitumor and cardiac activities. Treatment of cAMP with several bases and alkyl bromides gave alkyltriesters of cAMP (2), N6,N6,2'-O-trialkyl cAMPs (3), N6,2'-O-dialkyl cAMPs (4) and 2'-O-monoalkyl cAMPs (5) in one step. N6,N6-dialkyl cAMPs (6) were prepared from 2'-O-tosyl cAMP by the similar alkylation, followed by detosylation. Synthesis of N6-monoalkyl cAMPs (7) was achieved by the reductive alkylation of cAMP with aldehydes in one step. Alkyl triesters of cAMP exhibited antitumor activities against P815 cells. N6-mono and N6,N6-dialkyl cAMPs showed significant cardiac activities.

Alkylation↗