Biomedical subjects

S Nishihara

Publications and source records attributed to S Nishihara.

At least 55 records · Page 3Linked to original sources

PubMed1997

Temporal bone fractures inducing facial nerve paralysis: a new classification and its clinical significance.

Based on the analysis of the operative findings in 97 temporal bone fractures with respect to location, site of injury to the facial nerve and associated damage, we propose a new classification of the temporal bone fracture, using types 1, 2, 3 and 4, as previously described. Three-dimensional helical CT is valuable for assessment of fracture type. The incidence of each fracture type and the site of the injury to the facial nerve are described and the surgical significance of the classification is discussed.

Facial Paralysis↗

PubMed1996

Synthesis and characterization of a carbene-generating biotinylated N-acetylglucosamine for photoaffinity labeling of beta-(1-->4)-galactosyltransferase.

A photoreactive N-acetylglucosamine derivative, N-[2-[2-[2-(2-biotinylaminoethoxy)-ethoxy]ethoxy]-4-[3-(trifluo rom ethyl)-3-H-diazirin-3-yl]benzoyl]-N4-[2-(acetylamino)-deoxy-beta-D -glucopyranosyl]-L-aspartamide (BDGA), was synthesized as a carbene-generating biotinylated probe for UDP-galactose:N-acetylglucosamine beta-(1-->4)-galactosyltransferase (GalT). The photoaffinity labeling experiments of bovine GalT with BDGA under various condition were examined based on the quantitative chemiluminescent detection of the biotinyl residue which was photochemically introduced into in GalT protein. A progressive decrease in the yield of specific photolabeling was observed upon lowering the incubation temperature from 37 degrees C to 20 degrees C or 4 degree C. The amount of photoincorporation was also decreased when UMP was not included in the incubation mixture. Using a crude protein mixture of recombinant human GalT, a band corresponding to the glutathione S-transferase fusion GalT protein was also specifically visualized. Furthermore, combine use of BDGA photolabeling with an immobilized avidin was found to be effective for the selective retrieval of photolabeled GalT from a reaction mixture containing a large amount of unlabeled GalT protein. The results obtained clearly demonstrate that the covalent biotinylation using the carbene-generating photoaffinity reagent BDGA would be useful for the analysis of acceptor substrate binding sites within the GalT protein.

Acetylglucosamine↗

PubMed1996

Molecular genetic analysis of the human Lewis histo-blood group system. II. Secretor gene inactivation by a novel single missense mutation A385T in Japanese nonsecretor individuals.

The Lewis histo-blood group system comprises two major antigens, Lewis a and Lewis b. The Lewis b antigen is a product of two fucosyltransferases, the alpha(1,3/1,4)fucosyltransferase (Lewis enzyme; Fuc-TIII) encoded by the Lewis gene and an alpha(1,2)fucosyltransferase which is not required for synthesis of Lewis a antigen. An enzyme responsible for secreting ABH antigens into body secretions (secretor enzyme) is also one of alpha(1,2)fucosyltransferases. A candidate gene encoding secretor enzyme Sec2 gene was recently cloned by Rouquier, S., Lowe, J. B., Kelly, R. J., Fertitta, A. L., Lennon, G. G., and Giorgi, D. ((1995) J. Biol. Chem. 270, 4632-4639) and Kelly, R. J., Rouquier, S., Giorgi, D., Lennon, G. G., and Lowe, J. B. ((1995) J. Biol. Chem. 270, 4640-4649) who demonstrated a G428A nonsense mutation (Trp143 to terminal codon) in Sec2 of nonsecretors. However, the G428A nonsense mutation discovered in the Sec2 gene of nonsecretors in an ethnic group other than Japanese was not found in any of 45 Japanese nonsecretors, whereas one Filipino who had been erroneously registered as a Japanese possessed the G428A mutation heterozygously. In order to explore the Sec2 gene of a Japanese population, we performed a molecular genetic analysis of the Sec2 gene on 226 Japanese individuals, 21 in a family study and 205 in a random sampling study. We discovered two novel mutations in the Sec2 gene, an A385T missense mutation (Ile129 to Phe) that results in inactivation of Sec2-encoded alpha(1,2)fucosyltransferase and a C357T silent mutation which is irrelevant to amino acid substitution, in Japanese nonsecretors. The analysis of Japanese individuals using the polymerase chain reaction-restriction fragment length polymorphism method found three alleles in the Sec2 gene, the first having no mutation, the second having a C357T mutation, and the third having both C357T and A385T mutations, which we designated as Se1, Se2, and sej, respectively. Among 226 Japanese individuals, 40 having a Le(a+b-) phenotype and 5 having a Le(a-b-) nonsecretor phenotype were homozygous for sej/sej, whereas 149 having a Le(a-b+) phenotype and 32 having a Le(a-b-)-secretor phenotype possessed at least one Se1 or Se2. The frequencies of occurrence of Se1, Se2, and sej among 410 alleles examined in a random sample of 205 Japanese individuals were 15, 46, and 39%, respectively, indicating a rather wide distribution of the sej allele in the Japanese population. The results show that the Sec2 gene really encodes the secretor enzyme alpha(1,2)fucosyltransferase and indicate that a ethnic group-specific nonsense or missense point mutation in the Sec2 gene determines nonsecretor status. The phylogenic aspect and biological significance of the Se and Le genes are discussed.

Amino Acid Sequence↗

PubMed1996

Genetic evidence for the Lewis enzyme, which synthesizes type-1 Lewis antigens in colon tissue, and intracellular localization of the enzyme.

To determine whether the Lewis enzyme responsible for the Lewis blood type antigens on erythrocytes synthesizes the Lewis antigens on normal cells and cancer cells in colon tissue, we performed genotyping of the Lewis gene by the PCR-RFLP method and by immunohistochemical staining of Lewis antigens and the Lewis enzyme with specific monoclonal antibodies (mAbs) in colon tissues obtained from 100 colon cancer patients. Five of the 100 patients were identified as homozygotes for the mutant Lewis gene, i.e., the le/le genotype that cannot encode functional Lewis enzyme. The cells in both the normal and cancerous regions of colon tissue from these five le/le patients were completely devoid of staining with mAbs against Lewis antigens with the type 1 chain, i.e., Lewis a, Lewis b, and sialyl Lewis a. In contrast, the cells in cancerous regions of the colon tissue of the 95 patients with the Le/Le or Le/le genotype positively stained with all three mAbs, anti-Lewis a, anti-Lewis b, and anti-sialyl Lewis a. The cells in the cancerous regions of the colon tissue of the five le/le patients stained with DU-PAN-2 mAb, whose recognizing epitope is known to be sialyl Lewis c, a precursor structure of sialyl Lewis a. By immunohistochemical staining with FTA 1-16 mAb, which is directed at the human Lewis enzyme, we were able to demonstrate for the first time that the enzyme is localized in the Golgi area of the colon epithelial cells of patients with the Le/Le or Le/le genotype. No staining was observed in the Golgi area of the cells of the patients with the le/le genotype. From these results, we conclude that individuals with the Le/Le or Le/le genotype possess a functional Lewis enzyme synthesizing fucosylated type-1 Lewis antigens in the Golgi apparatus of the colon epithelial cells, but that individuals with the le/le genotype are devoid of the Lewis enzyme in the Golgi apparatus, resulting in an inability to synthesize Lewis antigens with the type-1 chain, and that it is inappropriate to use CA19-9, whose antigenic epitope is defined as sialyl Lewis a, as a tumor marker in patients with the le/le genotype.

Antibodies, Monoclonal↗

PubMed1996

Laser Doppler vibrometer (LDV)--a new clinical tool for the otologist.

We describe a laser Doppler system (LDS) that can be used clinically for the measurement of tympanic membrane (TM), malleus and prosthesis head displacement in response to sound inputs of 80-to 100-dB sound-pressure level (SPL). It also has the potential for use in the operating room to perform measurements of prosthesis and stapes displacement. The information provided by such testing gives the otologist knowledge of TM and ossicular function that is unique in evaluating middle ear function; it should help select the best type of reconstruction in a given case and direct us toward new and better methods of TM and ossicular reconstruction. The results of umbo displacement measurements in 95 human ears are reported. Examples are provided of LDS measurements in representative ears and how they can be of help to the clinician. The potential of multisite TM-displacement testing is demonstrated in two temporal bones, including before and after partial ossicular replacement prosthesis (PORP) insertion.

Audiometry, Pure-Tone↗

PubMed1995

Genetic and enzymatic evidence for Lewis enzyme expression in Lewis-negative cancer patients.

It has been observed that the frequency of individuals with Lewis-negative erythrocytes is significantly higher in cancer patients than in healthy controls. In this study, 20 of the 66 (30.3%) patients with various cancers were typed as Lewis negative from their erythrocytes, while the same frequency in healthy controls was 11.1%. These 20 patients were divided into three groups based on the presence of Lewis blood group antigens and alpha 1-->4-fucosyltransferase in their salivas: group I, 6 patients who had both Lewis antigens and alpha 1-->4-fucosyltransferase activity; group II, 8 patients who had no Lewis antigens but possessed alpha 1-->4-fucosyltransferase activity; group III, 6 patients who had neither Lewis antigens nor alpha 1-->4-fucosyltransferase activity. The genotyping of Le genes by the PCR-RFLP methods, which have been developed and established by us recently, demonstrated that all 14 patients from groups I and II possess Le gene homozygously (Le/Le) or heterozygously (Le/le), whereas all 6 patients from group III were le/le homozygotes. Only the 6 patients from group III were identified as the genuine Lewis-negative individuals. The immunohistochemical staining of the colorectal tumors also showed that the Lewis antigens could be detected on the tumors from groups I and II but not from group III.

Base Sequence↗

PubMed1995

Murine monoclonal antibody recognizing human alpha(1,3/1,4)fucosyltransferase.

We prepared a mouse monoclonal antibody, FTA1-16, that specifically recognizes human alpha(1,3/1,4)fucosyltransferase without crossreactivity to any other members of the alpha(1,3)fucosyltransferase family. The specificity was confirmed by both immunofluorescense staining of native antigens in the Golgi apparatus and Western blotting analysis, using stable transformant cells transfected with each gene of the alpha(1,3)fucosyltransferase family. Western blotting analysis on a series of human tumour cell lines from various tissues revealed that some epithelial cancer cell lines from digestive organs expressed an amount of alpha(1,3/1,4)fucosyltransferase in good correlation with expression of sialyl Lewis a antigen. Immunohistochemical staining by FTA1-16 on colon cancer tissues revealed enhanced expression of the enzyme in cancer cells in comparison to normal cells. Finally, the antigenic epitope recognized by FTA1-16 was determined using truncated recombinant peptides which were expressed in E. coli. A minimal length determined was a fragment, amino acid positions 132-153, of the alpha(1,3/1,4)fucosyltransferase.

Amino Acid Sequence↗

PubMed1995

Measurements of the stapes superstructure.

Ten human stapes from fresh temporal bones were measured to obtain relevant distances of the stapes superstructure. The dimensions of the parts of the superstructure are as follows: 1) stapes head 1.14 mm (range, 0.91 to 1.49) in diameter parallel to the axis of the footplate and 0.83 mm (range, 0.65 to 1.08) perpendicular to it; 2) stapes head to shoulders 0.93 mm (range, 0.81 to 1.07), head to foramen 1.26 mm (range, 1.15 to 1.39), and head to lateral surface of stapes footplate 3.19 mm (range, 2.91 to 3.45); 3) neck width parallel to the axis of the footplate 1.18 mm (range, 0.88 to 1.47) and 0.64 mm (range, 0.48 to 0.88) perpendicular to it; 4) anterior crus 0.58 mm wide (range, 0.41 to 0.74) at the shoulder of the arch and 0.51 mm (range, 0.39 to 0.65) closer to the stapes footplate; 5) posterior crus 0.65 mm wide (range, 0.46 to 0.77) at the shoulder of the arch and 0.55 mm (range, 0.38 to 0.75) closer to the stapes footplate; and 6) maximum width of entire superstructure near footplate 2.48 mm (range, 2.06 to 2.98).

Age Factors↗

PubMed1994

Molecular genetic analysis of the human Lewis histo-blood group system.

The expression of Lewis histo-blood group antigen is determined by the Lewis type alpha(1,3/1,4) fucosyltransferase encoded in Fuc-TIII gene (Le gene) on chromosome 19. Weak hemagglutination reactions are often observed in the Lewis blood typing to cause false-negative reactions. The level of CA19-9 tumor marker, defined as sialylated Le(a) (sLe(a)), is influenced by the Lewis blood phenotype. The sLe(a) antigen is also considered to play a role in hematogenous metastasis of tumor cells. The accurate genotyping of Fuc-TIII gene would be, therefore, necessary for solving above questions. In addition to the two missense mutations previously reported by us, i.e. the T59G and the G508A, further sequence analyses revealed a new single base substitution, the T1067A, changing the Ile356 to Lys in the catalytic region. Polymerase chain reaction-restriction fragment length polymorphism methods were developed for the detection of these three missense mutations and applied in 15 Lewis negative (le/le) and 65 Lewis positive individuals (Le/Le or Le/le). These methods were found to be useful for genetic diagnosis for the Lewis histo-blood typing. All le alleles had the T59G mutation, whereas none of the Le alleles did. The le alleles were divided in two types, le1, having the G508A mutation, and le2, having the T1067A mutation. The T1067A mutation reduced the enzyme activity less than 10%, whereas the G508A mutation in the catalytic domain made the enzyme completely inactive. The frequency of occurrence of Le, le1, and le2 in the Japanese population by random sampling study was found to be 66, 30, and 4%, respectively.

Alleles↗

PubMed1994

Chemical analysis of neurotransmitter candidates in clonal cell lines from Drosophila central nervous system. I. ACh and L-dopa.

To characterize neuronal phenotypes, aminergic neurotransmitters, i.e. acetylcholine (ACh), catecholamine (CA)s and other biogenic amines (serotonin, octopamine), were surveyed in 10 colonial clones from one cell line of Drosophila larval CNS using HPLC-ECD system. ACh, which is a neurotransmitter in Drosophila, was found in 7 out of 10 clones. CAs, their metabolites, and other amines were not detected in any clones. However, all the 10 clones expressed L-dopa, a precursor of CAs. Consequently, seven clones expressed ACh and L-dopa. L-dopa as a novel neurotransmitter candidate was discussed.

Acetylcholine↗

PubMed1994

Newly established cell lines from Drosophila larval CNS express neural specific characteristics.

From the central nervous system of Drosophila melanogaster 3rd instar larvae, eight continuous cell lines have been established (named ML-DmBG1 to 8). Using ML-DmBG2, single colony isolation was carried out and six colonial clones were obtained. All reacted to the antibody to horseradish peroxidase, which is a neuronal marker in insects. Acetylcholine, a known neurotransmitter in Drosophila, was detected in three of the colonial clones by high performance liquid chromatography. Therefore, it is concluded that the established colonial clones are neural cells originating in the larval central nervous system. Among them, some variation was observed with respect to morphology, acetylcholine content, and reactivity to anti-HRP. The variation may reflect the heterogeneity of cells composing the central nervous system.

Acetylcholine↗

PubMed1994

[A case of revision of a cochlear implant].

The patient was a 41-year-old man who lost his hearing on the left at 7 years of age and on the right at 34 years of age due to meningitis. At 35 years of age a single-channel cochlear implant, 3M/House design, was implanted. Five years after the initial operation, the single-channel prosthesis was replaced by a multichannel device (Cochlear Corp.) because of the patients earnest wish to obtain better hearing. Explanation of the short electrode of the single-channel device was easy, but reimplantation of the longer electrode of multichannel device was somewhat difficult, probably because of the presence of the peri-implant fibro-osseous cuff in the Scala tympani. Single-channel and those of the multichannel speech data were compared in relation to performance in the same individual. The reimplanted multichannel device was equivalent to or outperformed the original 3M prosthesis. The patient preferred the hearing afforded by the multichannel device.

Adult↗

PubMed1994

Experimental models of ossiculoplasty.

Measurement of the acoustic properties of middle ear prostheses in an appropriate model prior to insertion in humans should be part of the routine of the prosthesis development and testing process, but it is not. This article describes a human temporal bone model suitable for such testing and discusses the results of several commonly used prostheses evaluated in the model. By comparing existing and new experimental prostheses in such a model, we should be better able to develop prostheses capable of providing improved hearing results following middle ear reconstruction.

Acoustics↗

PubMed1994

New knowledge about the function of the human middle ear: development of an improved analog model.

Conventional teaching regarding the acoustic function of the human middle ear is that it serves as an impedance matching system to offset the loss that occurs when sound passes from the low-impedance sound field to the high-impedance cochlear fluid. A transformer analogy is often used with the pressure transformation produced by the eardrum; footplate area ratio and the lever ratio considered to be approximately 27 dB. Recent data on middle ear function has shown this to be only partially correct. A transformer analogy is not appropriate since the pressure gain of the middle ear decreases above 1000 Hz and does not depend on the cochlear load at all frequencies. Experiments are described of umbo, malleus short process, and stapes displacement in human temporal bones using a laser Doppler measuring system (LDS). The measurements support previous studies that indicate that in addition to a roll-off in tympanic membrane function above 1000 Hz, there is slippage in the ossicular lever system that causes an increasing "lever ratio" above 1000 Hz, thought to be caused by translational movement of the ossicular rotation axis near the short process. An improved analog circuit model of the external and middle ear has been developed that produces results equivalent to those found in the temporal bones.

Acoustic Stimulation↗

PubMed1994

Experimental study of the acoustic properties of incus replacement prostheses in a human temporal bone model.

Many middle ear prostheses are available for reconstruction of a missing or damaged incus. Little is known of the relative acoustic performance of these prostheses in vitro and the parameters (mass, shape, tension, angulation, area of head) that modify this performance. This report describes experiments in a human temporal bone model comparing the effect on stapes displacement of six commercially available incus replacement prostheses (IRP). Measurements were performed using a laser Doppler vibrometer before and after incus removal and IRP placement between the tympanic membrane (TM) and stapes head. In addition, experiments were performed on the effect of increasing prosthesis mass, varying the tension between TM and stapes head, changing the surface area in contact with the TM, and comparing different TM contact sites. All prostheses tested showed reasonable acoustic performance compared to the baseline condition. Optimum tension between the TM and stapes head produced the best overall sound transmission. The mid-malleus and umbo locations were the best malleus contact sites; however, the posterior TM contact site also worked well. Increased mass improved low frequency transmission and impaired higher frequency transmission, whereas a larger contact area with the TM contributed to increased gain in the mid frequencies.

Aged↗

PubMed1993

Alpha (1,3/1,4)fucosyltransferase (FucT-III) gene is inactivated by a single amino acid substitution in Lewis histo-blood type negative individuals.

Human alpha (1,3/1,4)fucosyltransferase (FucT-III) genes were cloned from genomic DNAs of seven Lewis negative (Le(a- b-)) individuals. Restriction mapping analyses revealed that an additional Pvu II site was created in the FucT-III genes from Lewis negative individuals. Four of these individuals were shown to be heterozygous for the Pvu II site and three were homozygous for it. The Pvu II site was produced by a single base substitution at the 508 nucleotide of coding sequence, G to A, resulting in the amino acid substitution, Gly to Ser at position 170. Another single base substitution, resulting in the change of Asp to Ala at position 336, was observed in the Lewis negative FucT-III gene which did not have the Pvu II site. The FucT-III enzyme was inactivated by these two mutations resulting in a single amino acid substitution in the catalytic region. All FucT-III genes, regardless of the Pvu II site, from Lewis negative individuals had a single base substitution, the T at position 59 to G, resulting in the change of Leu to Arg at position 20. This mutation, however, was not responsible for FucT-III gene inactivation.

Amino Acid Sequence↗

PubMed1993

Human alpha-1,3 fucosyltransferase (FucT-VI) gene is located at only 13 kb 3' to the Lewis type fucosyltransferase (FucT-III) gene on chromosome 19.

Human alpha-(1.3/1,4) fucosyltransferase (FucT-III) gene and alpha 1,3 fucosyltransferase (FucT-VI) gene were found in the 38-kb fragment isolated from a human cosmid library. These genes were present 13 kb apart in tandem orientation. The FucT-III gene has already been mapped on the Lewis locus of chromosome 19. This demonstrated that FucT-VI gene was localized close to the Lewis locus on chromosome 19.

Base Sequence↗

PubMed1993

Effect of changes in mass on middle ear function.

Vibrating systems such as the middle ear are affected by changes in mass. After disease or ear surgery, significant changes in mass may contribute positively or negatively to the postoperative hearing threshold. This article describes experiments in 15 human temporal bones of the addition or reduction of mass on the middle ear transfer function. Measurement of stapes and umbo vibration was performed using a Laser Doppler Vibrometer before and after the addition of different masses at several sites on the tympanic membrane (TM) and ossicular chain. The input was 61 pure tones swept from 147 to 19433 Hz at 80 dB SPL. The addition of mass onto the TM produced varying detrimental effects on sound transmission, depending on the location and amount of mass. The insertion of ventilation tubes, weighing 12 to 17 mg each, produced losses at 1.5 to 5.0 kHz compared with tympanotomy alone. Addition of mass to the umbo and malleus head produced a loss at mid and high frequencies, whereas addition of mass on the incus long process and stapes also produced a high-frequency decrease in stapes displacement. Reduction of TM mass by removal of the epithelium produced an increase, especially at 2.0 to 4.0 kHz.

Adult↗