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Biomedical subjects

Y Baba

Publications and source records attributed to Y Baba.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Interrelationship among nerve conduction velocity, amplitudes of compound muscle and compound nerve action potentials in diabetic neuropathy].

In order to clarify the relationship among amplitudes of compound nerve action potential (CNAP), compound muscle action potential (CMAP) and nerve conduction velocity parameters, data of nerve conduction studies were analyzed in 102 patients with diabetes mellitus. In motor conduction studies CMAP amplitudes after stimulations at the distal nerve trunk, and the polyneuropathy index (PNI), a mean percentage of normal for 12 indices from 4 nerves concerning to the velocity or long distance latency, were evaluated. CNAP was recorded in the median and ulnar nerves from an intrafascicularly inserted microelectrode at the elbow after wrist stimulation. CMAP amplitudes were high in the median and ulnar nerves, and were reduced in the tibial and peroneal nerves. A close relationship was found between PNI and CNAP amplitudes. Among CMAP amplitude parameters tibial nerve, not median or ulnar nerves, had a good correlation with PNI and CNAP amplitude. Along with the progression of diabetic neuropathy, neuropathic signs or symptoms become conspicuous, and nerve conduction velocity drops as is expressed by the PNI level, which reflects the change in nerve conduction velocity in the upper and lower limbs. At the same time CNAP amplitude or CMAP amplitude in the tibial nerve decreases, but in nerves of the upper limb CMAP amplitude doesn't always decrease. So, tibial nerve is best among CMAP amplitude parameters in evaluating the degree of diabetic neuropathy. It is necessary to judge the degree of diabetic neuropathy after due consideration of these facts.

Action Potentials↗
PubMed1998

Optimal image resolution for digital storage of radiotherapy-planning images.

PURPOSE: To evaluate the quality of digitized radiation-planning images at different resolution and to determine the optimal resolution for digital storage. METHODS AND MATERIALS: Twenty-five planning films were scanned and digitized using a film scanner at a resolution of 72 dots per inch (dpi) with 8-bit depth. The resolution of scanned images was reduced to 48, 36, 24, and 18 dpi using computer software. Image qualities of these five images (72, 48, 36, 24, and 18 dpi) were evaluated and given scores (4 = excellent; 3 = good; 2 = fair; and 1 = poor) by three radiation oncologists. An image data compression algorithm by the Joint Photographic Experts Group (JPEG) (not reversible and some information will be lost) was also evaluated. RESULTS: The scores of digitized images with 72, 48, 36, 24, and 17 dpi resolution were 3.8 +/- 0.3, 3.5 +/- 0.3, 3.3 +/- 0.5, 2.7 +/- 0.5, and 1.6 +/- 0.3, respectively. The quality of 36-dpi images were definitely worse compared to 72-dpi images, but were good enough as planning films. Digitized planning images with 72- and 36-dpi resolution requires about 800 and 200 KBytes, respectively. The JPEG compression algorithm produces little degradation in 36-dpi images at compression ratios of 5:1. CONCLUSION: The quality of digitized images with 36-dpi resolution was good enough as radiation-planning images and required 200 KBytes/image.

Humans↗
PubMed1998

Electrophoresis of long DNA molecules in linear polyacrylamide solutions.

Electrophoresis of long DNA (T4 DNA; 166 kb, S. pombe chromosomal DNA; 3-6 Mb) in linear polyacrylamide solutions was investigated by fluorescence microscopy and capillary electrophoresis. In the past studies on electrophoresis of long DNA in a polymer solution, it was reported that DNA migrates in 'U-shape conformation'. We found that at higher polymer concentrations, the shape of the migrating DNA changes from U shape to linear shape ('I-shape conformation'). In the migration mode with the I-shape conformation, the DNA moves with almost constant velocity and constant shape. However, the migration velocity does depend on the DNA size, and it is possible to separate DNAs under this I-shape motion. Actually, Mb-sized DNAs are well separated within 5 min in the region for the I-shape motion by means of capillary electrophoresis with a DC field. Considering that it takes 20 h to separate Mb-sized DNAs by standard pulsed-field gel electrophoresis (PFGE), this results will be useful for the separation of giant DNAs.

Journal Article↗
PubMed1998

Identification and characterization of a novel SH3-domain binding protein, Sab, which preferentially associates with Bruton's tyrosine kinase (BtK).

Protein interaction cloning method was used to identify a novel molecule, Sab, which binds to the SH3 domain of Bruton's tyrosine kinase (Btk), the deficient cytoplasmic tyrosine kinase in human X-linked agammaglobulinemia and murine X-linked immunodeficiency. Immunoprecipitation using the anti-Sab antibody identified the protein product of the gene as a 70 kDa molecule. While Sab does not have a proline-rich sequence, it was shown to bind to Btk through the commonly conserved structure among SH3 domains. Remarkably, Sab exhibited a high preference for binding to Btk rather than to other cytoplasmic tyrosine kinases, which suggests a unique role of Sab in the Btk signal transduction pathway.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Enhanced separation of DNA sequencing products by capillary electrophoresis using a stepwise gradient of electric field strength.

The effect of the electric field strength gradient on the separation of DNA sequencing fragments was investigated. We demonstrate that the stepwise gradient of electric field improves the separation of DNA sequencing fragments more than 500 bases in size and diminishes the analysis time for DNA sequencing of lager DNA fragments. The use of the electric field strength gradient induces an increase in the theoretical plate number as predicted by the theoretical formulation discussed in this paper.

DNA↗
PubMed1998

Base-specific separation of oligodeoxynucleotides by capillary affinity gel electrophoresis.

Capillary affinity gel electrophoresis was applied to sequence-specific and base composition-specific recognition of oligodeoxynucleotides, utilizing the formation of heteroduplexes between a nucleic acid analogue immobilized into the capillary gel and soluble oligodeoxynucleotides with different sequences. Capillary affinity gel electrophoresis using capillaries filled with a conjugated gel of polyacrylamide and a synthetic nucleic acid analogue [poly(9-vinyladenine)] was effective for the selective separation of hexathymidylic acid from a mixture of four homopolymers of A6, C6, G6, and T6 and for the complete resolution of five heteropolymers of hexadeoxynucleotides (TAAAAA, TTAAAA, TTTAAA, TTTTAA, TTTTTA). We also demonstrated that capillary affinity gel electrophoresis was useful for the selective and the sensitive sequence-specific recognition of sequence isomers of DNA (TTTTAA, TTTTAAT, TTTATA, and TTTTAA).

Affinity Labels↗
PubMed1998

Cyclin D1 expression as a prognostic factor in advanced hypopharyngeal carcinoma.

Hypopharyngeal carcinoma (HPC) has a poor prognosis. We investigated the expression of cyclin D1 in 34 advanced HPCs, and the value of cyclin D1 expression was evaluated as a predictive marker in terms of the prognosis of HPC, compared with other clinical factors. Using immunohistochemical staining, 20 of 34 patients showed positive immunoreactivity for cyclin D1. The statistical trend of the survival rate was lower in the cyclin D1-positive patients than in the cyclin D-negative ones (p = 0.0805). The predictive factors for the survival rate were effectiveness of neo-adjuvant chemotherapy (F = 8.698) (p = 0.0066), cyclin D1 expression (F = 6.244) (p = 0.0191) and N classification (F = 5.037) (p = 0.0335). The cyclin D1-positive patients had approximately four-fold higher mortality than the cyclin D1-negative ones. These data indicate that the expression of cyclin D1, in advanced patients with hypopharyngeal carcinoma is a useful marker for prognosis.

Adult↗
PubMed1998

The 21-kDa polypeptide (VAP21) in the rabies virion is a CD99-related host cell protein.

In our monoclonal antibody (MAb) stocks prepared against the BHK-21 cell antigens, two (#11875 and 28276) recognized a 21-kDa polypeptide (referred to as VAP21) which is efficiently incorporated into the rabies virion. By using these MAbs, we isolated the cDNA clones that encoded a polypeptide of 144 amino acids from our BHK-21 cell cDNA library. Based on the following evidence, the cDNA was assumed to encode a full-length sequence of VAP21 antigen: i) expression of the cDNA in animal cells resulted in the production of a polypeptide recognized by the two MAbs, and its electrophoretic mobility was the same as that of authentic VAP21 antigen; and ii) immunization with the products from the cDNA-transformed E. coli cells raised specific antibodies in rabbits that recognized a 21-kDa polypeptide in the virion. From the deduced amino acid sequence, it is suggested that the VAP21 antigen has a molecular structure of type-I transmembrane protein containing characteristic proline-rich and glycine-rich regions in its ectodomain. Homology searches resulted in finding homologous sequences (totally about 40% homology) in the human MIC2 gene product (CD99; 32-kDa) of T lymphocytes. These results suggest that the VAP21 antigen in the rabies virion is a cellular CD99-related transmembrane protein.

12E7 Antigen↗
PubMed1998

Dural carotid cavernous fistulas: role of conventional radiation therapy--long-term results with irradiation, embolization, or both.

PURPOSE: To evaluate the long-term results of irradiation alone or of embolization with or without irradiation in patients with dural carotid cavernous fistulas (DCCFs). MATERIALS AND METHODS: Between 1984 and 1996, symptomatic DCCFs in 26 patients were treated by using irradiation alone (protocol 1, n = 12) before April 1988 and by using embolization as an initial treatment (protocol 2, n = 14) during and after April 1988. When angiography showed no improvement after embolization, irradiation was added (n = 6). On the basis of drainage flow speed, DCCFs were classified as fast, medium, or slow. RESULTS: With irradiation alone, all six patients with slow- to medium-type DCCFs had cure with a mean follow-up of 62 months. Four of six patients with fast-type DCCFs had cure or improvement, but the remaining two had no change. In the embolization group, irradiation was added in six patients with fast-type DCCFs. With a mean follow-up of 24 months, four of the six patients had cures, one had improvement, and one had no clinical change. Those who underwent protocol 2 had cures significantly earlier than those who underwent protocol 1 (P < .05). CONCLUSION: Conventional radiation therapy resulted in cure of DCCFs in nine (75%) of the 12 patients and in improvement of signs and symptoms in one (8%). Fast-type DCCFs may not always be improved. Radiation therapy may be useful in DCCFs after embolization.

Adult↗
PubMed1998

Analysis of variable number of tandem repeats of human genome D1S80 locus using capillary electrophoresis with laser-induced fluorescence detector.

The conventional method of identifying individuals by DNA in the field of forensic medicine is slab gel electrophoresis, which is time-consuming, labor-intensive, and nonquantitative. Accordingly, the use of capillary electrophoresis with a laser-induced fluorescence detector (CE-LIF), human genome D1S80 locus, a DNA marker which has a variable number of tandem repeats (VNTR) on chromosome 1, was examined to improve DNA analysis for identification. Using an internal standard, fragment size of VNTR was accurately and rapidly determined.

DNA↗
PubMed1998

Analysis of a variable number of tandem repeats in a heart disease gene by capillary electrophoresis with laser-induced fluorescence detector.

Capillary electrophoresis with laser-induced fluorescence detector (CE-LIF) was successfully applied to the analysis of the variable number of tandem repeats (VNTR) in a human apolipoprotein B gene (APOB). Apolipoprotein B VNTR alleles containing more than 35 repeat units are a significant risk factor for heart disease. Thus, we developed a method for accurately determining the number of repeat units (16 bp) in the VNTR using capillary electrophoresis. The CE-LIF technique gave excellent resolution of APOB alleles differing by 2 or 4 repeat units over the range 600 to 1000 bp. The recommended conditions for the analysis of APOB VNTR loci by CE-LIF are as follows: effective length of capillary (100 microns i.d., 360 microns o.d.), 50 cm; running buffer, 50 mM Tris-borate 0.5% methylcellulose and 0.1 microM fluorescent dye YO-PRO-1; electric field, 150 V/cm.

Alleles↗
PubMed1998

[Basic studies on IL-2 gene therapy for head and neck carcinoma].

Basic studies on transduction of the interleukin-2 (IL-2) gene into tumor cells were carried out in order to develop a new immunotherapy for head and neck carcinomas. We transduced the IL-2 gene into KB cells using defective herpes simplex viral (HSV) amplicon vector as the gene transfer vehicle. A high level of IL-2 was produced by IL-2 gene transduced KB cells (KB/IL-2). Human peripheral blood mononuclear cells (PBMC) cultured in medium containing the culture supernatant of KB/IL-2 cells showed stronger cytotoxic activity against KB cells than the control. In in vivo studies, high levels of IL-2 and interferon-gamma (IFN-gamma) were detected in the serum of nude mice transplanted with KB/IL-2 cells. The spleen cells of KB/IL-2 cell-transplanted nude mice exhibited high cytotoxic activity. Three of 5 nude mice transplanted with KB/IL-2 cells were completely cured of their tumor, and all 3 mice survived for over 120 days. All 5 nude mice transplanted with KB/lacZ cells, and all 5 nude mice transplanted with KB cells died within 120 days as a result of tumor progression. In conclusion, transduction of IL-2 gene tumor cells was corroborated by the high level of IL-2 produced by KB/IL-2 cells. The mechanisms of tumor rejection on KB/IL-2 transplanted nude mice were thought to be that effector cells stimulated by IL-2 derived from transplanted KB/IL-2 cells killed tumor cells, and IFN-gamma produced by activated NK cells showed a synergistic effect on tumor cells-killing.

Animals↗
PubMed1998

MR of denervated tongue: temporal changes after radical neck dissection.

PURPOSE: The purpose of this study was to evaluate the temporal changes of MR imaging in the denervated tongue after a radical neck dissection. METHODS: One hundred seventy-four consecutive MR studies in 116 patients with radical neck dissections for malignant tumors of the head and neck were evaluated retrospectively. Patients with tumors involving the tongue or hypoglossal nerve were not included in this study. RESULTS: Abnormal signal intensity and/or hemiatrophy on the side of the tongue operated on was seen in 22 patients who had hypoglossal paralysis after radical neck dissection. The denervated side of the tongue appeared hypointense to hyperintense relative to the normal side on T1-weighted images and hyperintense on T2-weighted images. Signal intensity ratios of the abnormal to normal muscles were 0.9-1.6 on T1-weighted images and 1.3-2.8 on T2-weighted images. High signal intensity on T1-weighted images appeared 5 months or more after the dissection, whereas on T2-weighted images, the most prominent increases in signal intensity appeared in the first several months after denervation. Hemiatrophy of the tongue was observed on MR images obtained more than 6 months after surgery. CONCLUSION: MR findings in the denervated tongue are compatible with histologic changes and are characterized by an enlarged extracellular fluid space or fatty infiltration. The pattern of signal intensity and the degree of hemiatrophy suggest the duration of denervation.

Adult↗
PubMed1998

Evidence for apoptosis signal-regulating kinase 1 in the regenerating palatal epithelium upon acute injury.

Apoptosis signal-regulating kinase 1 (ASK1), a recently identified mitogen-activated protein (MAP) kinase kinase kinase, is a key element in the mechanism of stress- and cytokine-induced apoptosis. However, pathophysiologic roles of ASK1 in vivo are poorly understood. In the present study, we analyzed the ASK1 expression in injured rat palate using an immunohistochemical approach to investigate the roles of ASK1 during the process of wound healing. In the normal rat palatal epithelium, a weak cytoplasmic staining of ASK1 was observed in keratinocytes of the prickle cell layer. After mucoperiosteal injury of the palate, ASK1 was clearly observed in the suprabasal keratinocytes surrounding the wound. ASK1 expression was most evident at Day 2 after injury in the edge of the migrating epithelium. Thereafter, the intensity of ASK1 staining decreased gradually until the re-epithelialization was completed at Day 10 to 14. A staining with the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end-labeling method identified a number of apoptotic keratinocytes in the suprabasal layers at the healing edge. Active induction of epithelial apoptosis was readily detectable from Day 5 after injury. In double-staining analysis, the temporal and spatial pattern of ASK1 expression correlated well with the appearance of apoptotic keratinocytes. p38 MAP kinase, a downstream component of ASK1, was found to be activated at the sites of ASK1 expression, suggesting that increased expression of ASK1 leads to activation of downstream MAP kinase signaling pathway in vivo. These results suggest a significant contribution of ASK1 to the epithelial apoptosis in the process of mucoepithelial wound repair.

Animals↗
PubMed1998

MR sialography using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences.

We describe our preliminary experience with the half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences for MR imaging of the salivary gland ducts. In the majority of patients, the main parotid and/or submandibular gland ducts and large branches within the glands were detectable on MR images obtained in 2 seconds per section and within 3 minutes for the entire examination. MR sialography using HASTE sequences can be combined with conventional MR studies for the salivary glands.

Adult↗
PubMed1998

[Thymidylate synthase expression in patients with hypopharyngeal carcinoma].

We analyzed the relationship between clinical response to neo-adjuvant chemotherapy including 5-fluorouracil (5-FU) in patients with hypopharyngeal carcinoma (HPC) and thymidylate synthase (TS) expression in their tumors. TS expression was evaluated with immunohistochemical staining techniques on biopsy specimens from HPC patients. TS immunostaining was divided into four levels (TS0-TS3) according to its level and pattern. The relationship between prognosis, tumor size, nodal status, differentiation of tumor cells and TS expression were also investigated. There was a statistically significant association between the level of TS expression and tumor size (p < 0.01). In terms of the effectiveness of chemotherapy, tumor differentiation, nodal status and prognosis, a statistical difference was not found in TS expression. These results suggest that the level of TS expression may show the degree of tumor proliferation, but may not necessarily be useful to obtain a response to chemotherapy including other drugs, e.g., cisplatin and other derivatives of platinum.

Aged↗