Biomedical subjects

K Ohyama

Publications and source records attributed to K Ohyama.

At least 91 records · Page 5Linked to original sources

PubMed1997

Conformability and irritancy of adhesive tapes on the skin.

The relationship between the conformability of adhesive tape, the mechanical property of the adhesive tape not to interfere with skin movement, and irritation of the skin was investigated. In order to assess the conformability of adhesive tape to the skin, a uniaxial method employing film strips connected to a strain gauge was used to measure the elastic property of the skin, with or without application of various elastic tapes. The tension loaded on the strain gauge was measured while the skin was extended by 15% of its original length in a direction across the humeral axis on the flexor side of the upper right arm. The most elastic adhesive tape showed the best conformity to the skin. The same adhesive tapes were applied on the flexor side of both upper arms so that the tape held a piece of sanitary cotton in place for 24 h. Dermal irritation was not so remarkable in the skin under the inner part of the tapes. On the other hand, the skin reaction was much more severe on the skin under the edge portion of the applied tape which showed poor conformability to the skin. These findings seemed to indicate that the skin reaction was caused by localized distortion of the skin under the edge portion of the applied tapes, during movement of the underlying muscle. Actually, the distortion of the skin surface was great in the areas immediately outside the edge of the applied tape. In conclusion, adhesive tape conformable to skin movement reduced localized distortion of the skin during application, resulting in low irritation at the edge of the applied tape.

Adhesiveness↗

PubMed1997

Ototoxic effect of erythromycin on cochlear potentials in the guinea pig.

The mechanism of hearing loss due to the administration of intravenous erythromycin was investigated in the albino guinea pig, and it was found for the first time that this drug causes cochlear dysfunction. The endocochlear potential (EP) and the cochlear microphonics (CM) recorded at the first cochlear turn transiently decreased when erythromycin was administered intravenously at dosages of 100 and 150 mg/kg. The averaged maximum decrease in EP was 16 mV (n = 5) and 33 mV (n = 5) for 100 and 150 mg/kg, respectively. The maximum decrease in the CM was about 25% when the EP reached its lowest value with the injection of 150 mg/kg. A complete recovery of the EP and CM ensured within 20 minutes after each erythromycin dose. The perilymphatic perfusion of 3 mmol/L of erythromycin decreased the EP and CM; however, in contrast to the intravenous administration, the decrease of the CM was nearly complete and both the EP and CM were irreversible. Hearing loss due to intravenously administered erythromycin could likely be attributle to the transient dysfunction of the stria vascularis, although concomitant dysfunction of the central auditory pathway cannot be excluded.

Animals↗

PubMed1997

Separation of sialoglycoprotein fractions having influenza virus-receptor activity from human meconium and some of their chemical properties.

Three sialoglycoprotein fractions having reactivities against influenza A and B viruses (IV-A and IV-B) and influenza virus-hemagglutinin (IV-HA), were obtained by gel filtration using a Sephacryl S-300 column and an Asahipak GS-710 HPLC column from water-soluble fraction prepared from human meconium (ME-WSF). Molecular weights of sialoglycoproteins in these fractions were estimated as 746 kDa (P-Fr. 1-3), 4470 kDa (P-Fr. 1-2) and a more than 10,000 kDa (P-Fr. 1-1), respectively. The other in P-Fr. 2, with molecular weight estimated as 92 kDa, revealed positive but weak reactivity against IV-HA; however, the fraction did not show positive reactivity against either IVs-A or -B. All these fractions contained sialoglycoproteins with a high content of carbohydrates (31.0-59.3%, w/w). From their carbohydrate compositions, it can be suspected that sialoglycoproteins having O-glycosidically linked carbohydrate chains were predominating in the three fractions. In conclusion, it is suggested that at least three sialoglycoproteins with influenza virus-receptor activity showing different chemical properties to each other exist in human meconium.

Amino Acids↗

PubMed1997

Further observations on programmed cell death in the epiphyseal growth plate: comparison of normal and dyschondroplastic epiphyses.

The objective of the investigation was to provide information on apoptosis in the normal epiphysis and to assess apoptosis in the plate of the dyschondroplastic chick. Apoptosis was evaluated using two terminal deoxynucleotide transferase end-labeling procedures, DNA fragmentation and nuclear morphology. We found that there was a minimal level of apoptosis in the dyschondroplastic cartilage. In the tibial dyschondroplastic (TD) lesion itself, only about 3% of cells are positive in the articular and proliferative regions; 11% of prehypertrophic chondrocytes are stained by the end-labeling procedure, and most of the cells are localized around vascular channels at the calcifying front. This finding suggests that dyschondroplasia is linked to impairment of apoptosis, and as a result the tissue contains immature cells that have outlived their normal life span. In contrast, in the normal plate, we noted that when the proliferative period was complete, the cells became terminal transferase positive; in addition, chondrocytes in the normal plate exhibited DNA fragmentation. Semiquantitative analysis of stained chondrocytes in the growth plate indicate that in the proliferative zone 15.5% of cells are terminal deoxynucleotidyl transferase (TUNEL) positive; in contrast, 44% of postmitotic chondrocytes are stained by the TUNEL procedure. The presence of a sharp border between the pre- and postmitotic zones suggests that the stimulus for apoptosis is maturation dependent and reflects local metabolic control. We also examined apoptosis in metaphyseal osteoblasts. We found that adjacent to the epiphysis, many osteoblasts were undergoing apoptosis. In more mature sites in the metaphysis, there was less cell death, indicating that osteoblast apoptosis was delayed and cells were completing their normal life cycle. Although terminal transferase end-labeled cells were not seen in articular cartilage, we noted that fibroblasts, in the perichondrial ligament surrounding the articular as well as the epiphyseal regions of the plate, were undergoing apoptosis. Apoptosis at this site may be related to lateral expansion of the cartilages, reflect a high cell turnover rate at the junction between the tissues, and result from paracrine signals received from the underlying cartilage.

Animals↗

PubMed1997

Restoration of seminiferous tubular function after discontinuation of long-term gonadotropin-releasing hormone agonist administration in premature male rats.

We examined whether seminiferous tubular function develops normally after discontinuation of long-term gonadal suppression in premature male rats. Wistar male rats 4 weeks old were subjected to the injection of gonadotropin-releasing hormone (Gn-RH) agonist or normal saline solution as control for 12 weeks. The rats were sacrificed 0 and 6 weeks after discontinuation of the treatment. Histological examinations of the seminiferous tubules immediately after cessation of the Gn-RH agonist treatment demonstrated a stage-related change in specific germ cells. Seminiferous tubules of Gn-RH agonist-treated rats were narrow and irregular in shape, and contained significantly fewer spermatids and pachytene spermatocytes at stages VII to XIV than those in controls. A complete development of spermatogenesis was histologically observed 6 weeks after cessation of the treatment. Leydig cells became atrophic without any reduction in cell number immediately after the treatment, but Leydig cells grew rapidly and were similar in appearance to those in control rats 6 weeks after cessation of the treatment. Serum testosterone concentrations were noticeably suppressed immediately after cessation of the treatment (P < 0.01 vs. control) and reached a similar level to those of controls 6 weeks after the cessation. Testes weights were significantly lower in Gn-RH agonist-treated rats than in control rats and had not fully developed 6 weeks after cessation of the treatment (P < 0.01 vs. control). These results suggest that the testicular function develops normally after cessation of the long-term gonadal suppression in premature rats, although the increase in testicular weight may be slightly influenced.

Animals↗

PubMed1997

Freeman-Sheldon syndrome: case management from age 6 to 16 years.

OBJECTIVE: This is the first description of long-term follow-up of a case of Freeman-Sheldon syndrome. Microstomia was treated with a mouth expander for 2 to 3 hours per day before active orthodontic treatment. Separate impressions were necessary in each quadrant of both upper and lower jaws because of limited mouth opening. CONCLUSION: Orthodontic treatment improved the patient's Class II malocclusion, which was accompanied by crowding and a deep bite.

Adolescent↗

PubMed1997

[Dynamic behavior of guinea pig middle ear].

The dynamic behavior of the middle ear was studied in living guinea pigs by using a laser Doppler vibrometer coupled to a compound microscope. Placing glass microbeads 20 microns in diameter on four points of the tympanic membrane and six points of the ossicles, their velocity amplitudes were measured under a constant stimulus of 65 dB SPL. Velocity responses of the four points on the tympanic membrane differed over the frequency range from 0.1 kHz to 3 kHz. At low frequencies, the malleus and incus rotated around an axis running from the malleus head to the incus short process. At middle frequencies, the whole ossicle had a piston-like motion. At high frequencies, the malleus and incus rotated around a vertical axis running through the ossicles, while the stapes had a hinge-like movement.

Animals↗

PubMed1997

[A novel diagnostic method for allergy "LUCICA HRT"].

We developed a novel glass microfiber-based histamine release test (HRT) which is characteristic of response of basophil leukocyte to allergens in vitro. It allows the determination of 20 allergens (10 for inhalation allergy, and the other for food allergy) at the same time using a small amount of whole blood. For 158 patients of inhalation allergy and 135 patients of food allergy, they were evaluated by HRT, CAP-RAST, skin test, and provocation test. The concordance of HRT, CAP-RAST, and skin test were 78%, 72%, and 62% in inhalation allergy, and 84%, 71%, and 81% in food allergy, respectively. The specificity of HRT, CAP-RAST, and skin test were 63%, 37%, and 19% in inhalation allergy, and 92%, 63%, and 83% in food allergy, respectively. The positive predictive value of HRT, CAP-RAST, and skin test were 79%, 71%, and 63%, respectively. The false positive ratio of HRT (14%) was lower than that of CAP-RAST (42%). The sensitivity of CAP-RAST was higher than that of HRT. In addition, we experienced a case of patient who showed significant improvement by treatment. At initial stage, not only the symptoms were erythema and scratching but also HRT, CAP-RAST, and skin test resulted in positive. Four months later, he had no allergic symptoms, HRT resulted in negative, but CAP-RAST and skin test resulted in still positive. From these results, we concluded that CAP-RAST is good for screening of etiological allergens and that HRT is a useful diagnostic method for the confirmation of a clinical allergy.

Adolescent↗

PubMed1997

Investigation of Vicia graminea lectin- and Vicia unijuga lectin-binding glycoproteins as novel oncofetal antigens in cyst and ascitic fluids of human ovarian tumors in benign, dysplastic, and malignant stages.

Perchloric acid-soluble fractions (PASFs) were obtained from cyst fluids of human benign ovarian mucinous cystadenoma, benign dermoid cyst, "borderline" mucinous cystadenoma, and malignant ovarian clear cell carcinoma, and from fluids of malignant embryonal carcinoma and malignant serous cystadenocarcinoma. PASFs from benign lesions did not react with Arachis hypogaea lectin (PNA), Vicia graminea lectin (VGA), or Vicia unijuga lectin (VUA). PASFs from "borderline" lesions reacted with PNA but did not react with VGA and VUA. PASFs from malignant tumors reacted with PNA, VGA, and VUA. These PASFs did not react positively against anti-M or -N sera. These results show that VGA- and VUA-binding glycoprotein (Vgu glycoprotein) exist in PASFs from malignant ovarian tumors, and that PNA-binding glycoprotein was present in PASFs from malignant and "borderline" ovarian tumors. Furthermore, we found the existence of Vgu glycoprotein in PASFs from various human cancer cell lines; however, the antigens were not found in PASFs from benign human cell lines.

Antigens, Neoplasm↗

PubMed1996

Cloning and sequencing of the para-type sodium channel gene from susceptible and kdr-resistant German cockroaches (Blattella germanica) and house fly (Musca domestica).

Using reverse transcription polymerase chain reactions (RT-PCR), the DNA sequence for the main membrane-spanning region (IS3 through IVS6) of the gene encoding the alpha-subunit of the para sodium channel of the German cockroach, Blattella germanica, has been determined. The overall structure of the open reading frame region of this B. germanica gene is very similar to that of the para gene of Drosophila melanogaster, and that of the partially sequenced para gene of Musca domestica. On the other hand, it is distinctly different from that of the DSC gene (Drosophila sodium channel). As a result of a side-by-side comparison of the para gene sequences of the susceptible CSMA strain and the kdr resistant VT strain of B. germanica, one mutation (TTG to TTC) at the approximate center of the IIS6 membrane-spanning segment was found to result in an amino acid change from L to F. While the functional meaning of this mutation for the operation of the para sodium channel remains to be studied, this region is very highly conserved among all sodium channels identified so far, and is one of the most hydrophobic areas of the entire alpha-subunit. For comparison, we have studied the same region of the para sodium channel of both kdr and susceptible SBO strain of the housefly, Musca domestica. We found the homologous type of mutation, CTT to TTT, resulting in the same amino acid alteration (L to F) at this site. However, in the case of houseflies both kdr and susceptible strains contained both L and F versions of the protein. The ratio of TTT to CTT was significantly higher in the kdr strain of M. domestica than in the three susceptible strains examined.

Amino Acid Sequence↗

PubMed1996

Occurrence of nuclear-encoded tRNAIle in mitochondria of the liverwort Marchantia polymorpha.

Although 29 tRNA genes have been deduced from the complete nucleotide sequence of the mitochondrial genome from the liverwort Marchantia polymorpha, a tRNAIle gene decoding AUU and AUC codons is conspicuously absent. In order to address the question of the possible involvement of nuclear-encoded tRNA, we isolated and identified three variant copies of the nuclear-encoded tRNAIle(AAU) gene from the liverwort. Northern analysis showed the presence of nuclear-encoded tRNAIle both in the mitochondrion and the cytosol, while both chloroplast DNA-encoded tRNAIle and nuclear-encoded tRNATyr were absent in liverwort mitochondria. These results unequivocally establish that import of nuclear tRNAIle into mitochondria indeed occurs in one of the most primitive plants, M. polymorpha.

Base Sequence↗

PubMed1996

cemA homologue essential to CO2 transport in the cyanobacterium Synechocystis PCC6803.

We have isolated mutants of Synechocystis PCC6803 that grew very slowly in a low-sodium medium, which is unfavorable for HCO3(-) transport, and examined two of these mutants (SC1 and SC2) for their ability to take up CO2 and HCO3(-) in the light. The CO2 transport activity of SC1 and SC2 was much lower than that of the wild type (WT), whereas there was no difference between the mutants and the WT in their activity of HCO3(-) transport. A clone containing a 3.9-kilobase-pair insert DNA that transforms both mutants to the WT phenotype was isolated from a genomic library of WT Synechocystis. Sequencing of the insert DNA in the region of mutations in SC1 and SC2 revealed an open reading frame (designated cotA), which showed significant amino-acid sequence homology to cemA encoding a protein found in the inner envelope membrane of chloroplasts. The cotA gene is present in a single copy and was not cotranscribed with any other gene(s). cotA encodes a protein of 247 amino acids containing four transmembrane domains. There was substitution of a single base in SC1 and two bases in SC2 in their cotA genes. A possible role of the cotA gene product in CO2 transport is discussed.

Amino Acid Sequence↗

PubMed1996

Neurotrophin-3 increases the DNA-binding activities of several transcription factors in a mouse osteoblastic cell line.

In the mouse osteoblastic cell line MC3T3-E1, the signaling responses of several DNA-binding proteins induced by the treatment of neurotrophin-3 were examined using electrophoretic mobility shift assay. Neurotrophin-3 increased binding activities in nuclear extracts of MC3T3-E1 cells to TPA-responsive element (TRE), cyclic AMP-responsive element (CRE) and serum-responsive element (SRE), but not binding activity in the nuclear extracts to c-Myc binding DNA element. Competition experiments revealed that the binding activity to TRE in the nuclear extracts of neurotrophin-3-treated MC3T3-E1 cells was entirely inhibited by the both unlabeled TRE and CRE probes. On the other hand, the binding activity to CRE was abolished by the unlabeled CRE probe but not by the same amount of unlabeled TRE probe. Moreover, immunodepletion/supershift assay using antibodies directed to Fos, Jun and CREB proteins, showed that the binding activities to TRE and CRE in the nuclear extracts were derived in part from these proteins.

Animals↗

PubMed1996

Molecular analysis of females manifesting thyroxine-binding globulin (TBG) deficiency: selective X-chromosome inactivation responsible for the difference between phenotype and genotype in TBG-deficient females.

T4-binding globulin (TBG) is the major transport protein of thyroid hormone in man. Inherited TBG abnormalities were manifested fully in hemizygous males and partially in heterozygous females and transmitted in an X-chromosome-linked fashion, compatible with its location on Xq21-22. We have previously reported that complete deficiency (CD) and partial deficiency (PD) in Japanese subjects resulted from two distinct mutations of the TBG gene, TBG-CDJ and TBG-PDJ, respectively. Recently, we encountered a female manifesting TBG-CD and herein investigated the molecular mechanisms. She was found to possess TBG-CDJ and common-type TBG (TBG-C) alleles by characterizing the TBG gene. Then, X-chromosome inactivation status was evaluated in her family members using a phosphoglycerate kinase (PGK) gene, located on Xq13. Three TBG-CDJ heterozygotes and one unaffected female, confirmed to be PGK heterozygotes for a polymorphic BstXI site, were analyzed. Only the CD female was shown to undergo selective inactivation by examining the BstXI site in amplified products after digestion with a methylation-sensitive enzyme, HpaII. Among an additional eight informative females with TBG deficiency, one heterozygous female for TBG-PDJ shared this selective inactivation pattern. Moreover, the X-chromosome with TBG-C was suggested to be inactivated selectively from the linkage of PGK and TBG alleles recognized in eight of nine family members. Selective X-chromosome inactivation was considered to be the cause of a female heterozygous for TBG-CDJ or -PDJ manifesting the same phenotype as a hemizygote.

Base Sequence↗

PubMed1996

Chloroplast and mitochondrial genomes from a liverwort, Marchantia polymorpha--gene organization and molecular evolution.

The complete nucleotide sequence of chloroplast DNA (121,025 basepairs, bp) from a liverwort, Marchantia polymorpha, has made clear the entire gene organization of the chloroplast genome. Quite a few genes encoding components of photosynthesis and protein synthesis machinery have been identified by comparative computer analysis. We also identified the complete nucleotide sequence of the liverwort mitochondrial DNA and deduced 96 possible genes in the sequence of 186,608 bp. The complete nucleotide sequence from chloroplast DNA comprises twenty introns (19 group II and 1 group I) in 18 different genes. One of the chloroplast group II introns separated the ribosomal protein gene in the trans-position. The mitochondrial genome also has thirty-two introns (25 group II and 7 group I) in the coding regions of 17 genes. From the evolutionary point of view, we describe the origin of organellar introns which gave the evidence for their vertical and horizontal transfers and their intragenic propagation, and RNA editing which was apparently lacking in the liverwort chloroplast and mitochondrial genomes.

Amino Acid Sequence↗

PubMed1996

[Direct observation of the vibration and the traveling wave on the basilar membrane of the guinea pig].

Basilar membrane vibration was investigated in guinea pigs by using a laser Doppler velocimeter. To monitor the physiological condition of the cochlea, compound action potentials and distortion product otoacoustic emissions were measured before and after each experiment. Sharply tuned (Q10dB : 4.6-7.0) mechanical vibrations were successfully observed in 190 preparations of 15 animals. In these animals, strong compressive nonlinearity of the basilar membrane response and steep phase lag above the characteristic frequency were observed clearly. These findings strongly support the existence of active mechanical elements that play important roles behind the auditory transduction in the cochlea.

Action Potentials↗

PubMed1996

[Effect of aging on distortion product otoacoustic emissions].

The effect of aging on distortion product otoacoustic emissions (DPOAE) was investigated in 58 ears of 32 volunteers with normal hearing DPOAE levels to tones with a fixed frequency ratio (f2/f1 = 1.2) were measured with the CUBDIS system (MIMOSA Acoustics, USA). Age dependency of DPOAE level was clearly observed both in frequency plots (DP-gram) and input-output functions. In elderly persons, DPOAE levels for higher frequency primaries were significantly lower than in younger persons, when no remarkable change of audiometry threshold was noted. These results imply that the DPOAE level can be a sensitive indicator for age-related cochlear dysfunction.

Acoustic Stimulation↗

PubMed1996

Mechanisms of glucocorticoid resistance in human leukemic cells: implication of abnormal 90 and 70 kDa heat shock proteins.

The unliganded glucocorticoid receptor is a multi-oligomer complex consisting of a ligand-binding protein with which two 90 kDa heat shock proteins (hsp90s) are associated. Upon binding of glucocorticoid to the receptor, the ligand-binding protein, which dissociated from hsp90s, enters the nucleus, binds to a specific site in DNA, and thus transmits signal(s). The 70 kDa heat shock protein (hsp70) also works as a molecular chaperone when the ligand-binding protein enters the nucleus. Regarding the mechanisms of glucocorticoid resistance, a decreased expression of glucocorticoid receptor and a mutant protein with low ligand binding affinity have been reported. In the present study, to address other mechanisms of glucocorticoid resistance, we examined the expression of hsp90 and hsp70 in addition to the number of glucocorticoid-binding sites and their affinity using glucocorticoid-sensitive and -resistant human leukemic cell lines. We showed that two of nine resistant cell lines with normal glucocorticoid-binding proteins express aberrant hsp90 and extremely low hsp70, while another seven resistant cell lines had decreased binding sites with normal hsps. These results suggest that there are at least two independent mechanisms of glucocorticoid resistance in human leukemic cell lines: the decreased ligand-binding sites and the abnormal hsps expression.

Antineoplastic Agents, Hormonal↗