Biomedical subjects

Y Sakakura

Publications and source records attributed to Y Sakakura.

At least 127 records · Page 7Linked to original sources

PubMed1992

Endogenous epidermal growth factor regulates the timing and pattern of embryonic mouse molar tooth morphogenesis.

The tooth organ provides a model for discrete patterns of morphogenesis over short periods of developmental time. Studies were designed to test the hypothesis that endogenous epidermal growth factor (EGF) functions to regulate multiple cusp molar tooth morphogenesis during embryonic mouse development. The relative levels of endogenous EGF and EGF receptor (EGFR) transcripts were determined in both enamel organ epithelia and dental ectomesenchyme by reverse transcription-polymerase chain reaction (RT-PCR) assays. EGF and EGFR were localized by immunohistochemistry; both antigenic determinants were demonstrated on the same odontogenic cells in cultured tooth explants. To examine EGF-mediated signal transduction, cap stage mouse molar tooth organs (E16) were cultured in serumless, chemically-defined medium as either (i) controls, or supplemented with (ii) tryphostin (an EGF receptor kinase inhibitor), (iii) tyrphostin plus exogenous EGF, and (iv) exogenous EGF. Antisense oligodeoxynucleotide (ODN) strategy was used to investigate the functions of endogenous EGF employing (i) non-treated control, (ii) sense ODN control, (iii) antisense ODN, (iv) exogenous EGF, (v) sense ODN with exogenous EGF, and (vi) antisense ODN with exogenous EGF. Tyrphostin inhibited DNA synthesis and produced a significant decrease in the volume of the explants. These effects were recovered by addition of exogenous EGF. Antisense ODN inhibition resulted in abnormal cusp formations, decreased DNA synthesis, total DNA, RNA and protein content, and decreased stellate reticulum and tooth explant volumes. The decreased tooth size was not uniform, the most pronounced effect was in the stellate reticulum. This pattern of changes was not seen when antisense ODN treatment was supplemented with exogenous EGF. These results suggest that during cap stage of odontogenesis endogenous EGF acts to stimulate DNA synthesis, which increases the cell number of specific phenotypes within the enamel organ epithelia, and thereby regulates molar tooth morphogenesis.

Animals↗

PubMed1992

Gene expression, signal transduction and tissue-specific biomineralization during mammalian tooth development.

Tooth development provides a paradigm for intrinsic molecular controls for cell- and extracellular matrix (ECM)-mediated biomineralization. The intent of this review is to evaluate the sequential timing and positional information prerequisite for tissue-specific biomineralization. Recent investigations suggest that 1,25-dihydroxyvitamin D3 functions to up-regulate VDR (vitamin D receptor) that in turn could induce structural gene products, including calcium-binding proteins and several ECM proteins (e.g., enamelins, amelogenins, dentine sialoglycoproteins (DSP) and dentine phosphoproteins (DPP)), resulting in dentine and enamel formation. Inhibition of regulatory gene products and/or their receptors likely results in hypoplastic and/or hypomineralized ECM as a direct consequence of down-regulated (1) transcription and/or translation of structural and regulatory genes, (2) posttranslational modifications, (3) and/or decreased calcium transport to the forming dentine and enamel matrices. Advances in serumless in vitro culture methodology; computer-assisted access to nucleic acid sequences for probes to define when, where, and how many specific regulatory and structural gene products are expressed; antisense oligodeoxynucleotides to inhibit specific translation; and microtechniques to analyze biomineralization all provide additional avenues to investigate tissue-specific biomineralization.

Animals↗

PubMed1992

[Maxillary prosthesis for better QOL--early setting and faster construction of maxillary prosthesis].

The maxillofacial prosthesis (MFP) is well accepted as one of the modalities to ameliolate the postsurgical crippling in the patients with maxillary malignancy. In this report, we analyzed 55 primary cases of MFP out of 100, from July, 1981 to July, 1987 in terms of the time of start after operation, and the duration and procedure of the MFP-making. MFP-making set about within 4 weeks in 35% of patients, 8 weeks in 25%, 12 weeks in 22%, and more than 12 weeks in 18%. The completion of MFP-making averaged 10 days. As a result of simplifying of MFP-making, we shortened a period requiring MFP-making within 3 days in recent 10 cases. There were no adverse effects of early wear of MFP after operation. We believe that early wear of MFP after operation improve the quality of life of patients with maxillary malignancy and considered that wear of MFP is not the completion of treatment, but is one of the procedures of treatment for the patients undergone maxillectomy.

Adolescent↗

PubMed1991

Human breast carcinoma cDNA encoding a galactoside-binding lectin homologous to mouse Mac-2 antigen.

A galactoside-binding lectin (Mr 29,000) has previously been identified in rat, mouse and human tissues. It is an abundant cell-surface component of inflammatory macrophages and their major non-integrin laminin-binding protein. It has also been found in the nucleus of other cell types. Here, we report the cloning and sequencing of a cDNA encoding the human galactoside-binding lectin from a breast carcinoma. The clone encodes a protein of 250 amino acids (aa) that is over 80% identical to its mouse and rat counterparts. The aa sequence has an N-terminal and a C-terminal, 'carbohydrate-binding', domain. The N-terminal domain consists of two parts. The first 41 aa are homologous to a transcription factor, i.e., the serum response factor. The adjacent part (aa 42-106) contains an unusual repeating element, that occurs seven times in human protein compared to nine times in rat and mouse. The C-terminal 'carbohydrate-binding' domain (aa 115-250) shows homology to L-14, another galactoside-binding lectin.

Amino Acid Sequence↗

PubMed1991

A technique for quantitative cytology of nasal secretions.

To quantitatively analyze cellular elements in mucopurulent nasal secretions from patients with chronic paranasal sinusitis, we studied five mucus-liquefying agents--dithiothreitol (DTT), ethylenediaminetetraacetic acid tetrasodium salt, propylene glycol, serratio peptidase and urea--with Hanks' balanced salt solution used as a control. Agents were compared for the number of cells, the mucus-liquefying effect and the staining characteristic of cells in cytocentrifuge-prepared smears. The results indicated that the treatment of nasal secretions with 10 mM DTT provides more clear and detailed cytological preparations for quantitative cytology of nasal secretions.

Cell Count↗

PubMed1991

ELISA to determine immunoreactive Pseudomonas aeruginosa elastase in chronic suppurative otitis media.

A sensitive sandwich ELISA has been developed to measure the levels of Pseudomonas aeruginosa elastase (PE) in ear discharges from chronic suppurative otitis media (CSOM) patients. Preincubation of the sample with EDTA-2Na before ELISA was employed to inhibit PE activity which hydrolyzes the anti-PE IgG antibody into a smaller molecular form. The PE levels of 10 middle ear effusions (MEE) from chronic otitis media with effusion were also measured. In CSOM, 9 of 10 samples had significant PE levels, ranging from 6.8 to 62.1 micrograms/ml, which were significantly higher than those in MEE (p less than 0.01), the majority of which was below the detection limit. Two samples of CSOM with the P. aeruginosa infection showed high PE levels. This sandwich ELISA for the measurement of PE is a very sensitive method requiring only a small sample amount.

Enzyme-Linked Immunosorbent Assay↗

PubMed1991

Short-term mineralization of dentin and enamel in the mouse embryonic molars cultured in serum-free, chemically-defined medium.

The present study was designed to demonstrate the short term mineralization of dentin and enamel, and to investigate the effects of sodium beta-glycerophosphate (Na-beta-GPO4) on calcification in a serum-free, chemically-defined medium. The first mandibular molars at the bell stage dissected from 18-day-old mouse embryos were used as explants, which were cultured by an improved flotation method. Calcification of enamel in the 18-day-old embryonic molars occurred within the 6th day of culture. In another experiment, the molar germs were cultured in a serum-free, chemically-defined medium supplemented with 1, 5 and 10 mM Na-beta-GPO4. Promotion of tooth mineralization was recognizable at very low concentrations, such as 1 mM Na-beta-GPO4, in 18-day-old embryonic tooth germs. The culturing system reported here shortens the time required for dentin and enamel calcification to one half or one third of that reported previously and therefore should prove useful for examining regulations for cytodifferentiation and morphogenesis in tooth germs and the mineralization of dentin and enamel.

Ameloblasts↗

PubMed1991

Role of transepithelial ion transport as a determinant of mucus viscoelasticity in chronic inflammation of the maxillary sinus.

Chronic sinusitis is a chronic inflammatory disease with fluid retention, most frequently in maxillary sinus. We measured both viscoelasticity of maxillary sinus fluid and bioelectric properties of maxillary mucosa in an attempt to correlate the mucus viscoelasticity with bioelectric properties. During sinus surgery, maxillary sinus fluid and maxillary mucosa were obtained from 15 patients with chronic sinusitis. Viscoelasticity was measured with an oscillating sphere magnetic rheometer within 24 h after sampling. Potential difference and short circuit current of maxillary mucosa mounted in Ussing chambers were measured before and after exposure of mucosal surface to amiloride. Both elasticity and viscosity showed significant positive correlation with percent inhibition of short-circuit current by amiloride. Our results indicate that the ion transport process plays a role in the determination of viscoelasticity of maxillary sinus fluid in chronic sinusitis.

Adult↗

PubMed1991

A quantitative study of the ciliary area of experimental otitis media with effusion in cats.

A quantitative electron microscopic study was performed to determine the extent of the ciliary surface area of the middle ear epithelium in cats. In normal cats, 97.8% of the middle ear mucosa in the hypotympanum and 45.9% in the upper part of the bulla were covered by cilia. Eustachian tube obstruction (ETO) significantly reduced the ciliary area to 73.1% in the hypotympanum and to 16.2% in the upper part of bulla at 1 week after ETO. Instillation of Escherichia coli lipopolysaccharide (LPS) or cat polymorphonuclear leukocyte (PMN) lysate into the middle ear cavity followed by ETO did not reduce the ciliary area, compared with ETO induced alone. Our results indicate that ETO reduces the ciliary area of the middle ear mucosa and that LPS or neutrophils do not enhance reduction of the ciliary area compared to ETO induced alone in this experimental condition.

Animals↗

PubMed1991

Rheological properties of middle ear mucus in relation to goblet cell population in cat.

Seventeen mucoid middle ear effusions were collected from the tympanic cavity of 15 cats 1 or 2 weeks after tubal obstruction. Middle ear mucosa was also taken both from the tympanic cavity and bulla, and the number of goblet cells was counted. Both elasticity (G') viscosity (eta') of the mucoid effusion were determined with an oscillating sphere magnetic rheometer and compared with goblet cell count. There was a significant correlation between G' and goblet cell population in the tympanic cavity. A similar significant correlation was observed between eta' and goblet cells. The G' and eta' values of the mucoid mucus were much higher than the optimal viscoelasticity for mucociliary transport. Results indicate that the mucus obtained in this study mainly originated from the goblet cells, and that its viscoelasticity was beyond ideal values for mucociliary transport.

Animals↗

PubMed1991

Rheological and biochemical properties of middle ear effusions from experimental otitis media in cats.

Both rheological and biochemical analyses were performed on middle ear effusions (MEEs) from cats with experimental otitis media with effusions (OME) induced by obstruction of the Eustachian tube. This study was undertaken in order to clarify the factors determining rheological properties (elasticity and viscosity) of MEEs. The viscoelasticity of the effusions had a positive significant correlation to fucose/total protein concentration (TPC), and a negative correlation to cathepsin B level/TPC. No correlation was observed between albumin level/TPC and viscoelasticity. These results indicate that in cats the rheological properties of MEEs depend on the level of secretory glycoproteins in MEEs and on the severity of inflammation in the early stage after tubal obstruction.

Albumins↗

PubMed1991

The relationship between proteases activity and glycoprotein levels in middle ear effusions from experimental otitis media in cats.

The relationship between lysosomal proteases activity (elastase and cathepsin B) and levels of mucous glycoproteins in middle ear effusions (MEEs) was studied using a cat model of otitis media with effusion (OME) induced by Eustachian tube obstruction (ETO). The ratio of cathepsin B activity to total protein concentration (TPC) in MEE was 25.6 +/- 19.4 RFU/g x dl-1 at 1 week after ETO, and increased with the duration of OME. The ratio of elastase activity to TPC had a significant correlation to total leukocyte count. The ratio of fucose levels to TPC, which is one of the parameters reflecting levels of mucous glycoprotein, at 1 week after ETO was significantly higher than that at both 2 and 4 weeks after ETO. The percentage of glycoprotein levels absorbed to wheat germ lectin was highest at 1 week after ETO, and decreased with the duration of OME. In conclusion, mucous glycoproteins in cat occupy a larger portion of glycoproteins in MEE at the early stage of OME, and elastase and other lysosomal proteases may play a role in both stimulation of mucin release from goblet cells and mucin degradation. The balance of these processes seems to be a key factor determining mucin levels in MEEs.

Albumins↗

PubMed1991

Effects of endotoxin and neutrophil lysate on experimental otitis media with effusion in cats.

Middle ear effusion (MEE) from otitis media with effusion (OME) contains large amounts of chemical mediators and substances from bacteria, which may act on the mucosa itself and cause further changes in the inflamed mucosa and MEE. To clarify the effects of such substances in MEE, we instilled endotoxin (LPS) or allogeneic neutrophil lysate (NL) into the middle ear cavity of OME induced by Eustachian tube obstruction (ETO). ETO + LPS and ETO + NL groups showed retention of a large amount of MEE as a characteristic difference between ETO alone group and these groups. The instillation of LPS into the middle ear cavity of the ETO model significantly increased the number of total cells and the ratio of the concentrations of albumin to total protein in MEEs. The instillation of NL significantly increased the number of goblet cells in the middle ear. These facts indicate that the pathology of OME may change in response to various factors added to MEE. Hence, we propose that a vicious circle of self-mediated inflammation is a possible causative factor for chronic OME.

Animals↗

PubMed1991

Quantitative histochemical study of secretory cells after short term tubal obstruction in the cat.

Quantitative histochemistry of goblet cells producing different types of glycoproteins was examined in cat middle ears with and without Euatachian tube obstruction (ETO). The goblet cell population significantly increased at 1 week after ETO and showed a tendency to decrease down to the normal level at 4 weeks after ETO. In the normal ears, approximately 85% of glycoprotein in the secretory cells were sulphated and 15% were neutral. ETO significantly increased goblet cell population containing sulphated glycoprotein at the expense of neutral glycoprotein. The results indicate that goblet cells can easily and within a short period be modified both in number and in intracellular glycoproteins by a tubal obstruction.

Animals↗

PubMed1991

ELISA for determination of immunoreactive free elastase and elastase in complex with alpha 1-antitrypsin in nasal secretions with sinusitis.

Sensitive double antibody sandwich ELISA methods was developed in order to quantify immunoreactive neutrophil elastase (NE) levels in nasal secretions with chronic sinusitis (CS). Microwell plate as a solid phase was coated with anti-NE antibody. Two different horseradish peroxidase (HRP) labelled antibodies used as the second antibody were anti-NE-HRP for measuring total (free + complexed) NE level and anti-alpha 1-antitrypsin (AT)-HRP for complexed NE level. Mean value of total NE was 31.0 +/- 20.7 micrograms/ml in nasal secretions from adult patients with CS, and the percentage of complexed NE in total NE was 33.7 +/- 21.4%. This sandwich ELISA is a useful method for measuring both total and complexed NE levels in nasal secretions.

Chronic Disease↗

PubMed1991

Neutrophil elastase and its complex with alpha 1-antitrypsin in soluble and insoluble fractions of nasal secretions of chronic sinusitis.

Immunoreactive neutrophil elastase (NE) and its complex with alpha 1-antitrypsin (AT) was measured by double antibody enzyme linked immunosorbent assay (ELISA) in nasal secretions of chronic sinusitis (CS). Nasal secretions were separated into two fractions: PBS-soluble and insoluble fractions. Elastolytic activity was also examined. Mean value of total NE level was 31.0 micrograms/ml in the soluble fraction, which was significantly lower than that in the insoluble fraction (71.9 micrograms/ml, p less than 0.01). On the other hand, the percentage of complexed NE in total NE in the soluble fraction (33.7%) was significantly higher than that in the insoluble fraction (12.1%, p less than 0.01). Elastolytic activity in the soluble fraction (23.4 RFU) was significantly lower than that in the insoluble fraction (170.5 RFU, p less than 0.01). NE with elastolytic activity exists in nasal secretions of CS, and active-free NE in the insoluble fraction could be a major source of enhancement and continuation of mucosal inflammation.

Amino Acid Sequence↗

PubMed1991

[Psychological states and personality as factors in the morbidity of head and neck malignant tumors].

Many publications have repeatedly indicated that there seems to be a correlation between neoplastic disease and certain types of psychological situations. However, such studies subjected malignant tumors in head and neck region are scanty so far. We applied Cornell Medical Index Health Questionnaire (CMI) and Maudsley Personality Inventory (MPI) to collect medical and psychiatric data from 86 patients (56 males and 30 females) with head and neck malignant tumors and 115 control patients (73 males and 42 females) with head and neck diseases other than malignant tumors. Analysis of CMI data using Diagnostic Sheet, Fukamachi's method and Modification of Abe's method, and analysis of each of Extroversion-Introversion scale scores, Neuroticism scale scores and Lie scale scores of MPI led the following conclusion. 1) Both male and female patients with head and neck malignant tumors showed to be more depressive than their control patients were. Especially, between the two patient groups in males, there was a statistically significant (p less than 0.05) difference. 2) Regarding neurosis, autonomic nerve dysfunctioning and extroversion-introversion, none of these factors seemed to be related with the morbidity of head and neck malignant tumors. Further exploration of this issue, with a special attention to the relationship between depression and head and neck malignancy should be conducted, if possibly, from a prospective point of view.

Adult↗

PubMed1991

[Conventional X-ray versus CT in diagnosis of chronic sinusitis in children].

The interpretation of conventional radiographic views for sinusitis in children has given rise to considerable controversy. Thirty-three children (66 sides of sinuses) aged from 4 to 15 years who were suspected of having chronic sinusitis were studied to determine the accuracy of conventional X-ray examination, comparing the results with those of CT. Coronal CT was taken after conventional X-ray examination (Waters and occipito-frontal views), and the time interval between these two examinations was 0 to 14 days (average 5.1 days). The rate of correspondence in diagnosis of sinus pathology between conventional X-ray views and CT was 74.3% in the maxillary sinus and 40.9% in the ethmoid. The rate of overestimation with conventional X-ray views was 24.2% in the maxillary sinus and 56.1% in the ethmoid, while that of underestimation was 1.5% and 3.0% in the maxillary and the ethmoid sinus respectively. The incidence of false positives according to conventional X-ray views was 8.0% in the maxillary sinus and 33.3% in the ethmoid. Our results indicate that Waters view is sufficient to diagnose maxillary sinus pathology in children. However, additional radiologic examinations, such as CT, are necessary in investigating the pathologic conditions of the ethmoid sinus, since diagnostic significance of occipito-frontal view for ethmoid pathology is doubtful in children. A routine preoperative CT is recommended, which allows a detailed evaluation of pathologic changes and anatomical relations of the ethmoid before embarking a surgical intervention for the ethmoid sinus in children.

Adolescent↗