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Biomedical subjects

H Kotani

Publications and source records attributed to H Kotani.

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

Adhesion onto and invasion into mammalian cells by mycoplasma penetrans: a newly isolated mycoplasma from patients with AIDS.

The newly identified mycoplasma, Mycoplasma pentrans shows remarkable pathobiologic properties: it adheres to cell surfaces, deeply penetrates into the cell, strongly hemadsorbs human red blood cells, and cytadsorbs human CD4+ lymphocytes and monocytes. These in vitro biologic activities of mycoplasmas have been previously shown to be associated with pathogenic virulence in vivo. Both adhesion and invasion clearly involve the organism's unique tip-like structure. Invading mycoplasmas often have their tip-like structure deeply buried in the cytoplasm of infected mammalian cells. Extensive invasion of the mycoplasma into the cytoplasm may kill the cells. The same pathobiologic processes of adhesion and invasion using the specialized tip-like structure are found on the epithelium in the patient's urogenital tract infected by M. penetrans. Both in vitro and in vivo findings suggest a possible pathogenic role of this newly discovered human mycoplasma and call for careful evaluation of its role in human diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Cloning and sequence analysis of the StsI restriction-modification gene: presence of homology to FokI restriction-modification enzymes.

StsI endonuclease (R.StsI), a type IIs restriction endonuclease found in Streptococcus sanguis 54, recognizes the same sequence as FokI but cleaves at different positions. A DNA fragment that carried the genes for R.StsI and StsI methylase (M.StsI) was cloned from the chromosomal DNA of S.sanguis 54, and its nucleotide sequence was analyzed. The endonuclease gene was 1,806 bp long, corresponding to a protein of 602 amino acid residues (M(r) = 68,388), and the methylase gene was 1,959 bp long, corresponding to a protein of 653 amino acid residues (M(r) = 76,064). The assignment of the endonuclease gene was confirmed by analysis of the N-terminal amino acid sequence. Genes for the two proteins were in a tail-to-tail orientation, separated by a 131-nucleotide intercistronic region. The predicted amino acid sequences between the StsI system and the FokI system showed a 49% identity between the methylases and a 30% identity between the endonucleases. The sequence comparison of M.StsI with various methylases showed that the N-terminal half of M.StsI matches M.NIaIII, and the C-terminal half matches adenine methylases that recognize GATC and GATATC.

Amino Acid Sequence↗
PubMed1992

Isolation and characterization of new restriction endonucleases from Vibrio parahaemolyticus: VpaK32I enzyme with the class-IIS heptanucleotide specificity, GCTCTTCN1/N4.

Six restriction endonucleases (ENases), classified into four different specificities, were found in a screen among 68 reference strains of Vibrio parahaemolyticus of human origin. Five of these ENases are isoschizomers of well-known ENases, while the remaining one, designated VpaK32I, is a novel and highly efficient class-IIS ENase with the hepatanucleotide recognition site, 5'-GCTCTTC(1/4)-3'.

Base Sequence↗
PubMed1992

Site-specific dissection of E. coli chromosome by lambda terminase.

We have succeeded the targeted cleavage of chromosomes by lambda terminase that introduces double-strand cleavages in DNA recognizing the lambda cos sequence. When chromosomal DNAs of various Escherichia coli K-12 strains were subjected to terminase digestion, all were found to contain two common cleavage sites. Therefore, DNAs from lambda lysogens in which lambda DNA was inserted at different chromosomal sites were specifically cleaved at one more additional site. The two sites, termed ecos1 and ecos2, were mapped at approximately 35.1' and 12.7' of E. coli genetic map. The ecos1 and ecos2 sites were included in qin and qsr' regions, respectively. Therefore, the cleavage sites were associated with cryptic prophages. Sequences at the ecos1 and ecos2 sites showed 98% homology to the lambda cos sequence, indicating high fidelity of sequence recognition by the terminase. Since the strategy for integration of a DNA segment into chromosomal DNA through homologous recombination has been established, the dissection method that uses lambda terminase should be applicable for gene mapping as well as construction of macrophysical maps of larger genomes.

Base Sequence↗
PubMed1992

Cloning and expression of the HpaI restriction-modification genes.

The genes from Haemophilus parainfluenzae encoding the HpaI restriction-modification system were cloned and expressed in Escherichia coli. From the DNA sequence, we predicted the HpaI endonuclease (R.HpaI) to have 254 amino acid residues (Mr 29,630) and the HpaI methyltransferase (M.HpaI) to have 314 amino acid residues (37,390). The R.HpaI and M.HpaI genes overlapped by 16 base pairs on the chromosomal DNA. The genes had the same orientation. The clone, named E. coli HB101-HPA2, overproduced R.HpaI. R.HpaI activity from the clone was 100-fold that from H. parainfluenzae. The amino acid sequence of M.HpaI was compared with those of other type II methyltransferases.

Amino Acid Sequence↗
PubMed1992

The usage period of dentures and their residual monomer contents.

The quantity of residual monomer content in 24 maxillary dentures was detected by gas liquid chromatography. The residual monomer contents tended to be lower in dentures used for long periods than in those used for short periods. Decreases in the quantities of residual monomer in acrylic resin dentures as a result of aging can be expressed in a hyperbola. The fitted curve also suggests that most of the loss could be accomplished in 5 years; however, complete loss of the residual monomer content takes many years.

Acrylic Resins↗
PubMed1992

Structure-activity relationships in human interleukin-1 alpha: identification of key residues for expression of biological activities.

To identify the sites important for the different biological activities of human interleukin-1 alpha (hIL-1 alpha), 56 single-amino acid-substituted mutants of hIL-1 alpha were produced in Escherichia coli using site-directed mutagenesis, and were examined for their biological activities such as mouse lymphocyte activating factor activity (LAF activity), cytostatic activity against human melanoma cells A-375 (A375 activity) and prostaglandin E2 (PGE2) inducing activity in human osteosarcoma cells MG-63 (PEI activity). Two amino acid residues, Asp26 and Asp151, were found to be important for these activities. The replacement of Asp26 by Val caused a decrease in LAF and PEI activities by one or two orders of magnitude and a slight decrease in A375 activity. The Tyr or Phe substitution for Asp151 caused decreases in LAF and A375 activities by one or two orders of magnitude and complete loss of PEI activity. The change from Asp151 to Lys or Arg resulted in marked decrease in LAF activity and complete loss of A375 and PEI activities. Since Asp26 and Asp151 are close to each other in the three-dimensional structure, the region involving these amino acids seems to be important for the biological activities of hIL-1 alpha.

Amino Acid Sequence↗
PubMed1992

Evaluation of cervical cord function using spinal evoked potentials from surface electrode.

Spinal evoked potentials from cervical skin surface (surface spinal evoked potentials) were measured to evaluate spinal cord function as a convenient method that precludes inserting electrodes into the epidural space, and results were compared with those of the former epidural recording method. Surface spinal evoked potentials were obtained from cervical skin surface over the C3, C5, and C7 spinous processes after median nerve stimulation in 18 normal subjects and 37 patients with a cervical lesion. In normal subjects, surface spinal evoked potentials consisted of three negative waves (N1, N2, N3). Abnormal N2 (80%) and abnormal N3 (100%) were observed in cervical myelopathy, and abnormal N2 was observed only in radiculopathy; this allows for differentiation between myelopathy and radiculopathy. Comparing preoperative and postoperative surface spinal evoked potentials, it was seen that improvement of clinical symptoms was proportional to that of surface spinal evoked potentials.

Adult↗
PubMed1992

Mycoplasma penetrans sp. nov., from the urogenital tract of patients with AIDS.

An unusual mycoplasma, which was isolated from the urine of a human immunodeficiency virus-positive male homosexual patient, has an elongated flask shape and two unique sharply divided internal compartments. The tiplike compartment is densely packed with fine granules, and the body compartment is loosely filled with coarse granules consistent with ribosomal structures. The organism has properties of adherence, hemadsorption, and cytadsorption and invades many different types of mammalian cells. Adhesion and penetration apparently involve the terminally located tiplike structure. Cholesterol is required for growth, and the mycoplasma ferments glucose and hydrolyzes arginine, but does not hydrolyze urea. The results of DNA homology studies revealed that this organism is not genetically related to previously described mycoplasma species that have the same biochemical properties. The results of serologic studies demonstrated that this organism is antigenically distinct from all previously described mycoplasmas. We propose that this new mollicute species should be named Mycoplasma penetrans sp. nov. The type strain is strain GTU-54-6A1 (= ATCC 55252).

Acquired Immunodeficiency Syndrome↗
PubMed1992

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting analyses of ureaplasmas isolated from dogs.

To define the antigenic relatedness among unspeciated ureaplasma strains isolated from dogs, four canine ureaplasma isolates representing four serotypes were compared with the five type strains of the established species in Genus Ureaplasma by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting. Although all the strains showed distinct electrophoretic patterns by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the Western blotting patterns were much more distinct. By Western blotting, the five type strains of established species reacted strongly with homologous antisera and showed slight cross reactions with heterologous antisera. However canine strains which showed little cross reactions with the established Ureaplasma species showed a variety of cross reactions among the four canine serotypes used.

Animals↗
PubMed1992

[A case of small cell undifferentiated carcinoma (SCUC) of the rectum treated with etoposide, cis-platinum and radiotherapy].

A 29-year-old-woman with recurrent cancer of rectum was treated with Etoposide, cis-platinum and external irradiation. Previous postoperative chemotherapies consisted of MMC, CPA, VCR and HCFU. Histologically, the tumor invaded in sheets and nests, and consisted of round to ovoid malignant cells with high nuclear/cytoplasmic and hyperchromatic nuclei with a coarse, clumped, or stippled chromatin pattern. Most cells demonstrated a positive reaction by Grimelius and NSE staining. Eight months after surgery, we switched to Etoposide cis-platinum and external irradiation, because of local recurrence. Etoposide (total 725 mg) and cis-platinum (total 100 mg) were injected into bilateral iliac artery and 60 Gy radiotherapy was performed. The patient showed a good response, and a complete response (CR) was evident for the following 42 months. Thus, Etoposide, Cis-platinum and radiotherapy are considered an effective combination therapy for a patient with small cell undifferentiated carcinoma.

Adult↗
PubMed1992

[Lymphoid infiltration of colon cancer and clinical significance of the skin test].

It was reported that lymphoid infiltration (LI) of colon cancer tended to be found more commonly in patients with colonic cancer in an early stage than in an advanced stage. This time, the correlation among LI of colon cancer, cell-mediated immunity and the cumulative 5-year survival rate was studied in 124 patients with resected colon cancer. The results were as follows: 1) The cumulative 5-year survival rate in patients with positive LI was higher than that in the patients with negative LI. 2) There was correlation between the degree of LI of the cancer and Su-PS skin reaction. 3) Postoperative cell-mediated immunity was reduced in the cases of poor prognosis. Therefore we insist on paying attention to immunochemotherapy for 24 months after surgery.

Colonic Neoplasms↗
PubMed1992

[Early diagnosis and management against perioperative fungus infection].

Candida spp. is frequently detected from perioperative patients, especially from those requiring central venous catheter (CVC) management. CAND-TEC could detect the blood fungus infection easily and quickly. We analyzed 438 specimens from 57 patients requiring perioperative CVC management for more than three weeks, and investigated usefulness of CAND-TEC comparing with other serological methods. The dilution rate of CAND-TEC showed a positive correlation with amount of beta-D-glucan which was measured by Toxicolor test and Endotoxin-specific assay. It also showed a positive correlation with amount of D-arabinitol. When blood samples diluted more than four times were positive with CAND-TEC, the patients were considered to be infected, and accumulative infection rate was up to 84.2% three weeks after introduction of CVC management. CAND-TEC would be useful in detecting Candida infection compared with conventional methods, and the fungus infection was much more frequent incidence than ever expected. It is important to detect fungus infection early and respond immediately to avoid nosocomial infection.

Candidiasis↗
PubMed1991

Newly discovered mycoplasma isolated from patients infected with HIV.

Mycoplasmas have been isolated from patients with acquired immunodeficiency syndrome (AIDS) and they may contribute to the pathogenesis of this disease. We have isolated repeatedly a previously unknown mycoplasma from the urine of an HIV-positive male homosexual and, subsequently, from the urine of 5 HIV-positive patients with AIDS. The mycoplasma was not found in the urine of 98 healthy control subjects. The organism has an unusual tip-like structure with densely packed fine granules and metabolizes both glucose and arginine for growth. Antigenic and DNA analyses show the organism to be distinct from other known mycoplasmas. The mycoplasma displays in-vitro activities associated with virulence in vivo. In addition, electronmicroscopy shows that the mycoplasma can invade and attach to various human and animal cells. We are investigating whether the new mycoplasma has a role in human disease.

Acquired Immunodeficiency Syndrome↗