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Biomedical subjects

Toshio Ohtani

Publications and source records attributed to Toshio Ohtani.

29 records · Page 2Linked to original sources
PubMed2002

Simultaneous collection of topographic and fluorescent images of barley chromosomes by scanning near-field optical/atomic force microscopy.

The present study investigated the applicability of scanning near-field optical/atomic force microscopy (SNOM/AFM) to observations of YOYO-1 stained barley chromosomes. Using this technique, topographic and fluorescent images in the same portion were obtained simultaneously, thus enabling the precise analysis of fluorescent structures in relation to the morphology of chromosomes. In YOYO-1 stained chromosomes, the fluorescent intensity roughly reflected the local amount and/or density of DNA in chromosomes. R-banding of chromosomes stained with YOYO-1 and methyl green was also observed clearly as bright spots of various sizes by this microscope. Thus, the SNOM/AFM is expected to become a useful tool for analysing the structure and function of chromosomes more precisely than before.

Benzoxazoles↗
PubMed2002

Useful technique for DNA-stretching and fixation.

We report on a useful technique for reproducibly straightening and fixing DNA molecules. When a droplet of DNA solution on surfaces is sucked up by pipet, surface tension at the moving air-water interface is sufficient to stretch the molecules. The point of this technique is the interaction control between surfaces and DNA molecules by polymer coating. With polymers containing pi-conjugation units (polyphenazasiline, PPhenaz and poly(vinylcarbazole), PVCz), many DNA were nicely stretched and fixed on surfaces. Furthermore, structural changes of pi-units in polymers affected DNA-stretching and fixation. By using atomic force microscopy (AFM) and scanning near-field optical/atomic force microscopy (SNOM/AFM), the feasibility of this technique for DNA observations was demonstrated.

DNA↗
PubMed2002

Pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a heritable disease characterized by dermal, ocular, and vascular lesions that result from degeneration of the elastic fibers. Recently, the ATP-binding cassette subfamily C member 6 (ABCC6) gene has been demonstrated to be responsible for PXE, and 43 mutations have been identified to date. However, it is still unknown now mutations in the ABCCC6 gene can lead to manifestations of PXE.

Humans↗
PubMed2002

Direct visualization of abasic sites on a single DNA molecule using fluorescence microscopy.

A new method was developed to allow direct visualization of damaged sites on individual DNA molecules. Fluorescence in situ hybridization on extended DNA molecules was modified to detect a single abasic site. Abasic sites were specifically labeled with a biotinylated aldehyde-reactive probe and fluorochrome-conjugated streptavidin. The light emitted by a single fluorochrome-DNA complex was calibrated. The number of abasic sites on the DNA molecule was estimated by counting each fluorochrome-DNA complex. The present study directly visualized and characterized the abasic sites of single DNA molecules.

DNA↗
PubMed2002

Imaging of chromosomes at nano-meter scale resolution using scanning near-field optical/atomic force microscopy.

Topographic and fluorescent images of whole barley chromosomes stained with YOYO-1 were observed simultaneously by scanning near-field optical/ atomic force microscopy (SNOM/AFM). The chromosome was relatively smooth and flat in the topographic images and no significant difference in height was present between regions of high fluorescent and low fluorescent intensity in the chromosomes. The telomeric region, labeled by fluorescence in situ hybridization (FISH) method, was also observed by SNOM/AFM at high resolution, and fluorescent signals of the telomeric region were clearly defined on the topographic image of chromatin fibers on the chromosome at the nano-meter scale level. Although the telomeric signals were usually visualized as a single fluorescent region at the end of sister chromatids by conventional light microscopy, they were observed separately as two fluorescent regions, less than 100-200 nm distance, using the SNOM/AFM. The SNOM/AFM offers great potential in identifying particular single gene location on chromosomes in the near future.

Benzoxazoles↗
PubMed2002

Mechanical elongation of the centromere in the barley metaphase chromosome.

The present study investigated the mechanical elongation of the centromere in the barley chromosomes by a microneedle manipulation method for the structural analysis of the chromosomes. Chromosomes were extracted from barley root cells, affixed on a cover slip by a standard preparation method, and elongated in either distilled water, phosphate buffered saline (PBS), or 2 x sodium saline citrate (SSC). The mechanical property of the chromosome elongation was assessed by the measurement of the force required for the elongation of chromosomes. This assessment has shown that the chromosomes in distilled water were much firmer than those in the PBS or 2 x SSC. To confirm the elongation of the centromere, the elongated chromosomes were investigated by fluorescence in situ hybridization with a centromere probe. The fluorescence information indicated that the extent of the loosening of the centromere during elongation differed depending on the buffers used; the centromere elongated in 2 x SSC was more loosened than that in the PBS. Atomic force microscopy also revealed the structure of the unpacked centromere after the mechanical elongation, when rows of fibrous structures about 30 to 50 nm thick were clearly observed in the centromere elongated in 2 x SSC. The investigation of elongated chromosomes should prove useful for an understanding of the structural analysis of chromosomes.

Centromere↗
PubMedDate not supplied

Nano-scale imaging of chromosomes and DNA by scanning near-field optical/atomic force microscopy.

Nano-scale structures of the YOYO-1-stained barley chromosomes and lambda-phage DNA were investigated by scanning near-field optical/atomic force microscopy (SNOM/AFM). This technique enabled precise analysis of fluorescence structural images in relation to the morphology of the biomaterials. The results suggested that the fluorescence intensity does not always correspond to topographic height of the chromosomes, but roughly reflects the local amount and/or density of DNA. Various sizes of the bright fluorescence spots were clearly observed in fluorescence banding-treated chromosomes. Furthermore, fluorescence-stained lambda-phage DNA analysis by SNOM/AFM demonstrated the possibility of nanometer-scale imaging for a novel technique termed nano-fluorescence in situ hybridization (nano-FISH). Thus, SNOM/AFM is a powerful tool for analyzing the structure and the function of biomaterials with higher resolution than conventional optical microscopes.

Bacteriophage lambda↗
PubMedDate not supplied

Topical FK506 (tacrolimus) therapy for facial erythematous lesions of cutaneous lupus erythematosus and dermatomyositis.

Tacrolimus is a prototype of a class of topical immunosuppressive agents with great potential for the treatment of inflammatory skin diseases. Topical tacrolimus therapy was applied to facial skin lesions in 11 cases of cutaneous lupus erythematosus (LE) and dermatomyositis. Of the 11 patients, 6 (3 systemic LE, one discoid LE and 2 dermatomyositis) showed a marked regression of their skin lesions after tacrolimus therapy, but 4 patients (3 discoid LE and one dermatomyositis) were resistant to the therapy. A good response was observed for facial erythematous lesions with edematous or telangiectatic changes in systemic LE and dermatomyositis. In discoid LE with typical discoid lesions, tacrolimus brought no improvement. Topical tacrolimus will become a new tool for managing the skin lesions of collagen diseases.

Administration, Topical↗
PubMedDate not supplied

Digital gangrene associated with idiopathic hypereosinophilia: treatment with allogeneic cultured dermal substitute (CDS).

In the present case study, the patient was a 65-year-old man who suddenly developed purpuric and necrotic lesions with severe pain in his fingers and toes. Laboratory investigations revealed marked eosinophilia (77.9%), but there was no evidence to support a diagnosis of parasitic infections, allergic disease, neoplasm or connective tissue disorder. The histopathological findings did not show any distinct vasculitis, but there were obliterative changes of the arterioles. The digital gangrene gradually progressed and was unresponsive to corticosteroid therapy. The patient eventually underwent amputation of the distal phalanges. We applied allogeneic cultured dermal substitute (CDS) to the skin defect. The allogeneic CDS was prepared by culturing fibroblasts on a two-layered sponge of hyaluronic acid and atelo-collagen. This CDS is able to release a number of cytokines including VEGF. The present case had a good clinical result.

Aged↗
PubMedDate not supplied

Endotoxin shock due to Vibrio vulnificus infection.

A 54-year-old man with hepatitis C fell into shock with symptoms similar to enterocolitis after ingesting an undercooked barbecued mackerel. Most of his eruptions developed into annular erythema with small vesicles. He had taken high dose corticosteroids with intravenous cefotiam. His eruptions improved, but his shock state was exacerbated on Day 2. Treatment for endotoxin shock was initiated using piperacillin, intravenous immunoglobulin (IVIg), and hemoperfusion with Polymyxin B immobilized fiber (PMX-F), which resulted in shock reversal. The serum IL-6 value was 118,000 pg/mL on admission, and decreased to 2040 pg/mL on Day 3. On Day 6, the results from the culture of skin biopsy specimens showed the diagnosis as Vibrio vulnificus septic shock. Debridement was not needed, which is thought to be essential to Vibrio vulnificus sepsis. The changes in the serum IL-6 levels demonstrated that hemoperfusion with PMX-F and IVIg therapy was practical for Vibrio vulnificus septic shock.

Humans↗