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Biomedical subjects

Y Higuchi

Publications and source records attributed to Y Higuchi.

At least 181 records · Page 10Linked to original sources
PubMed1994

Increased attenuation in odontogenic keratocysts with computed tomography: a new finding.

An increased attenuation area (IAA) is sometimes seen in the cystic cavity of odontogenic keratocysts (OKCs) on CT scans. The significance of IAA was compared radiologically and histologically in 26 cysts in which a provisional diagnosis of OKC had been made. First, the presence of IAA in the cystic cavity was assessed. Then, relationship between the presence of IAA and data obtained from the cysts, including the CT and histological findings and the visual appearance of the cyst contents, was evaluated. An IAA was frequently seen in large multilocular cysts. There was no relationship between the presence of IAA and aggressive features of the cyst on CT or the cyst contents. Histologically, subepithelial inflammation was often observed in the cysts with IAA. In order to ascertain whether the IAA was due to the keratin mass, a CT scan of a bundle of hair in a water bath was performed and shown to have a similar density. Our study demonstrated that IAA in cystic cavities results from desquamated keratin. Since this seems to occur in long-standing or inflamed multilocular OKCs, it could be used as a significant finding in the diagnosis of OKC.

Adolescent↗
PubMed1994

Squamous cell carcinoma of the oral cavity consisting of band-like nests.

Four squamous cell carcinomas of the oral cavity shared common histological and clinical characteristics. The primary lesion was situated at the floor of the mouth or the tongue. The cancer cell nests were band-like. The border between nests and stroma was smooth and distinct, with the continuity of the basement membrane being well maintained. The response to preoperative chemoradiotherapy was relatively poor. Although the lesion was locally advanced, no cervical metastasis was detected. No recurrence has occurred after the operation.

Aged↗
PubMed1994

Disseminated Trichosporon infection. A case report and immunohistochemical study.

An autopsy case of disseminated Trichosporon beigelii infection in a patient with acute promyelocytic leukemia is presented. We diagnosed the T beigelii infection with immunoperoxidase method using our rabbit antiserum to T beigelii. The diagnosis of T beigelii infection is difficult, because of its close resemblance to Candida species in both clinical features and histopathologic findings. We could consistently identify T beigelii in tissue sections with the present immunohistologic method. We conclude that the immunoperoxidase method using antiserum to T beigelii is very useful to diagnose T beigelii infection.

Cadaver↗
PubMed1993

Induction of diabetes is influenced by the infectious virus and local expression of MHC class I and tumor necrosis factor-alpha.

To study self reactivity, a transgenic mouse model has been established in which the lymphocytic choriomeningitis virus (LCMV) glycoprotein (gp) is expressed in the beta-islet cells of the pancreas (rat insulin promoter (RIP)-gp). These mice (H-2b) do not spontaneously develop diabetes; however, infection with the LCMV strain WE rapidly induces hyperglycemia. In this study, comparative analysis of H-2k RIP-gp-transgenic animals demonstrated that the haplotype influences the incidence and kinetics of diabetes and alters the requirement for the CD4+ T cell subset. This study also showed that the properties of the virus expressing the self target Ag determined whether hyperglycemia occurred in RIP-gp-transgenic mice. Various LCMV strains were able to induce diabetes in RIP-gp-transgenic animals, whereas infection with a recombinant vaccinia virus expressing LCMV-gp (vacc-gp) did not induce diabetes. However, vacc-gp could induce diabetes in double (RIP-gp/TCR)-transgenic mice, where the majority of CD8+ T cells expressed a receptor specific for LCMV-gp, suggesting that a critical number of self-reactive T cells must be activated to induce disease. Notably, histologic analysis of pancreata taken various days after LCMV or vacc-gp infections indicated that induction of diabetes coincided with an increase in MHC class I expression on the islets of Langerhans. Additional studies with vacc-gp were done to determine other factors that possibly enhance autoimmune attack. Transgenic mice expressing both LCMV-gp and TNF-alpha under the control of the RIP were infected with vacc-gp, and 50% of RIP-gp/TNF-alpha-transgenic animals became hyperglycemic. These data suggest that the increased local lymphocyte traffic as a result of TNF-alpha expression attracts activated gp-specific T cells, enhancing the possibility of hyperglycemia. Collectively, these results demonstrate that the induction of diabetes in this model is influenced by the MHC haplotype, the infectious agent, TNF-alpha expression, the level of MHC class I expression, and the induction of a threshold number of self-reactive CTL.

Animals↗
PubMed1993

Induction of programmed cell death (apoptosis) by influenza virus infection in tissue culture cells.

The process of cell death caused by influenza virus infection in cultured MDCK and HeLa cells was analysed. This infection gave rise to nuclear fragmentation and chromatin condensation accompanied by chromosomal DNA fragmentation into oligonucleosomes. Chromosomal DNA fragmentation progressed concomitantly with cell lysis of MDCK cells and HeLa cells, producing high and low yields of virus particles, respectively, indicating that the extent of cell lysis was not proportional to the virus production. The endonuclease inhibitor zinc blocked DNA fragmentation in MDCK cells. Cycloheximide inhibited DNA fragmentation as well as cell lysis. Inhibition occurred when the drug was added to the medium within 2 h after infection but not efficiently at 4 h or later. Infection induced the Fas Ag gene, which encodes a possible apoptosis-mediating molecule, in the early infectious stage followed by the expression of Fas Ag on the cell surface. These results suggested that influenza virus infection causes apoptotic death of cultured cells, and their fate might be determined at an early stage of the infection by induction of an apoptotic gene.

Animals↗
PubMed1993

Safety and accuracy of dipyridamole thallium myocardial scintigraphy in elderly patients.

This study examined mainly the adverse effects of 201Tl myocardial scintigraphy with dipyridamole (D-Tl) in 73 elderly patients over 70 years old in comparison with those in 65 younger patients. Fifty-five of 73 elderly patients (75%) and 49 of 65 younger patients (75%) had a persistent or dipyridamole-induced perfusion defect on D-Tl. The hemodynamic changes induced by dipyridamole as well as the incidence of cardiac and noncardiac adverse effects were similar in both groups and no serious adverse effect occurred in either group. Secondly, we examined the procedure's usefulness for detecting ischemic heart disease in elderly and younger patients. Dipyridamole induced perfusion defect was noted in 21 elderly patients and in 24 younger patients (N.S.). Among the patients in whom coronary angiography was performed, significant coronary artery stenosis was found in 5 of 8 elderly patients and 17 of 20 young patients (N.S.). In patients with one or two-vessel disease, the area with dipyridamole induced ischemia was concordant with the stenotic area seen on coronary angiography in 3 of 3 elderly patients and 12 of 13 younger patients (N.S.). Thus, the safety and usefulness of D-Tl for detecting myocardial ischemia were comparable in elderly and young patients.

Age Factors↗
PubMed1992

Expression of a tumor necrosis factor alpha transgene in murine pancreatic beta cells results in severe and permanent insulitis without evolution towards diabetes.

Mice bearing a tumor necrosis factor (TNF) alpha transgene controlled by an insulin promoter developed an increasingly severe lymphocytic insulitis, apparently resulting from the induction of endothelial changes with features similar to those observed in other places of intense lymphocytic traffic. This was accompanied by dissociation of the endocrine tissue (without marked decrease in its total mass), islet fibrosis, and the development of intraislet ductules containing, by places, beta cells in their walls, suggesting a regenerative capacity. Islet disorganization and fibrosis did not result from lymphocytic infiltration, since they were also observed in SCID mice bearing the transgene. Diabetes never developed, even though a number of potentially inducing conditions were used, including the prolonged perfusion of interferon gamma and the permanent expression of a nontolerogenic viral protein on beta cells (obtained by using mice bearing two transgenes). It is concluded that (a) a slow process of TNF release in pancreatic islets induces insulitis, and may be instrumental in the insulitis resulting from local cell-mediated immune reactions, but (b) that insulitis per se is not diabetogenic, lymphocyte stimulation by cells other than beta cells being necessary to trigger extensive beta cell damage. This provides an explanation for the discrepancy between the occurrence of insulitis and that of clinical disease in autoimmune diabetes.

Animals↗
PubMed1992

Identification of a tissue-specific regulatory element within the murine CD14 gene.

We previously isolated and sequenced the 5'-flanking region of the mouse CD14 (mCD14) gene (Matsuura, K., Setoguchi, M., Nasu, N., Higuchi, Y., Yoshida, S., Akizuki, S., and Yamamoto, S. (1989) Nucleic Acids Res. 17, 2132). To define the regulatory elements that control expression of the mCD14 gene, we analyzed the structure of the 5' end of the gene, including a region further upstream of that determined previously. Sequentially 5'-deleted, chimeric, and point mutated clones were tested for the ability to stimulate chloramphenicol acetyltransferase. An 8-base pair sequence, TGATTCAC, at position -255, which resembled the consensus sequence of the 12-O-tetradecanoylphorbol-13-acetate-responsive element (TRE), enhanced the expression of the chloramphenicol acetyltransferase gene in macrophage (aHINS-B3) and non-macrophage (glioblastoma G203 and myeloma NS1) cells. The enhancing ability of the TRE-like sequence (TLS), however, was markedly reduced in G203 cells but not in aHINS-B3 cells when the TLS was followed by the sequence immediately downstream. The TLS and sequence immediately downstream were capable of binding nuclear proteins which were unique to aHINS-B3 cells and macrophages, suggesting that these unique protein regulate the specific expression of the mCD14 gene. Binding of AP-1 to the TLS was also found in aHINS-B3 and G203 cells. Although it is uncertain whether AP-1 is involved in expression of the mCD14 gene, the effect of AP-1 in non-macrophage cells was inhibited by a nuclear protein which binds to the sequence immediately downstream of the TLS.

Animals↗
PubMed1992

XELE--a polypeptide model-building program for a graphics workstation.

A model-building program, XELE, for use in protein crystallography has been written in C under UNIX on a graphics workstation. This program makes full use of the X Window system to display the electron density distribution and to manipulate the polypeptide model, and therefore is named XELE. It utilizes a fast three-dimensional rendering package, Dorè, and is portable to other types of graphics workstations. A part of the program for the man-machine interface uses the library of X Window and X Toolkit, and therefore is highly interactive. The structure analysis program package, PROTEIN, is also implemented in an interactive mode using X Window, and has been interfaced with XELE.

Computer Graphics↗
PubMed1992

Cervical island skin flap for intraoral repair following cancer surgery.

Seventy three patients with oral cancer were operated on using the cervical island skin flap of Farr et al. (1969). Primary sites of the lesions were the tongue, floor of the mouth and lower gingiva. Most of the patients received total doses of 22.5 Gy of radiation and 110 mg bleomycin as a preoperative treatment. Among the 73 patients, complete necrosis of the skin island was observed in 3 cases. There was half necrosis in 4 cases, one quarter necrosis in 6 cases and marginal necrosis in 17 cases. The flaps in 43 patients completely survived. Results were better in the operations undertaken in the last 4 years in which a superficial layer of deep cervical fascia on the sternocleidomastoid muscle was included in the flap.

Adult↗
PubMed1992

Sequence analysis of the large (L) protein of simian virus 5.

The complete nucleotide sequence of the large (L) protein gene of simian virus 5 (SV5) was determined from cDNA of the genomic RNA and mRNA, and found to be 6804 bases in length, exclusive of a poly(A) tract. The sequence contained an open reading frame of 6765 nucleotides encoding 2255 amino acids. Results of dot matrix comparisons of the L protein of SV5 with those of human parainfluenza type 3 virus and Sendai virus indicated that there are five conserved domains, and that each domain contains characteristic sequence(s). The L protein of SV5 was detected in purified virions using antiserum directed against an oligopeptide corresponding to the N-terminal region.

Amino Acid Sequence↗
PubMed1992

[The usefulness of dipyridamole stress myocardial scintigram as a preoperative test for detecting ischemic heart disease before vascular surgery].

We evaluated the usefulness of dipyridamole 201Tl myocardial scintigraphy (DS) for detecting myocardial ischemia in 18 candidate for vascular surgery. DS indicated significant thallium redistribution in 6 patients. Coronary angiography was performed in 5 of these 6 patients and revealed significant coronary artery disease in all patients. As a result, operation was cancelled in 4 patients with severe coronary artery disease. One of these cases died of acute myocardial infarction after being discharged from hospital. One other patient was operated after percutaneous transluminal coronary angioplasty. Another patient was operated knowing that he had significant but mild coronary artery disease. Subsequently, operations were performed in 14 patients. No serious cardiac event occurred in these 14 patients except one case with T wave inversion without myocardial enzyme elevation. Thus, we concluded that DS was a useful method for detecting ischemic heart disease and prevent cardiac event associated with vascular surgery.

Aged↗
PubMed1991

Evaluation of x-ray diffraction data from protein crystals by use of an imaging plate.

A system has been developed which uses an imaging-plate diffraction apparatus to obtain structure factors for protein crystals. The latter is connected to a graphics workstation through an Ethernet. Pixel data from an imaging plate are transferred via the Ethernet to a workstation and processed to give the structure factors. The quality and precision of the diffraction data were examined from the point of view of spatial uniformity, linearity with exposure, decay with time, and reproducibility. X-rays from an 55Fe source and Debye-Scherrer rings from Si powder were used for calibration purposes. Finally, diffraction data were obtained and evaluated for lysozyme and cytochrome c-553 using this system. The results were satisfactory in terms of sensitivity and precision.

Protein Conformation↗
PubMed1991

1H NMR studies on ferricytochrome c3 from Desulfovibrio vulgaris Miyazaki F and its interaction with ferredoxin I.

The 1H NMR signals of the heme methyl, propionate and related chemical groups of cytochrome c3 from Desulfovibrio vulgaris Miyazaki F (D.v. MF) were site-specifically assigned by means of 1D NOE, 2D DQFCOSY and 2D TOCSY spectra. They were consistent with the site-specific assignments of the hemes with the highest and second-lowest redox potentials reported by Fan et al. (Biochemistry, 29 (1990) 2257-2263). The site-specific heme assignments were also supported by NOE between the methyl groups of these hemes and the side chain of Val18. All the results contradicted the heme assignments for D.v. MF cytochrome c3 made on the basis of electron spin resonance (Gayda et al. (1987) FEBS Lett., 217 57-61). Based on these assignments, the interaction of cytochrome c3 with D.v. MF ferredoxin I was investigated by NMR. The major interaction site of cytochrome c3 was identified as the heme with the highest redox potential, which is surrounded by the highest density of positive charges. The stoichiometry and association constant were two cytochrome c3 molecules per monomer of ferredoxin I and 10(8) M-2 (at 53 mM ionic strength and 25 degrees C), respectively.

Binding Sites↗
PubMed1991

Congenital dermoid fistula of the lower lip.

A case of congenital dermoid fistula of the lower lip is presented. The lesion consisted of a major cystic portion, a proximal tubelike extension that opened in the lower lip as a small sinus (pit) near the left commissure, and a distal cordlike extension that entered into the left mental foramen. The cystic cavity was lined with keratinizing stratified squamous epithelium, and many sebaceous glands, sweat glands, and hair follicles were seen subcutaneously. The differential diagnosis and the pathogenesis of the lesion are also discussed.

Adolescent↗