Tannins are one of polyphenolic compounds. Polyphenols are classified into two groups in terms of their reaction to gelatin, i.e., hydrolyzable (gelatin-soluble) and polymeric (gelatin-precipitable) polyphenols. They are present in a wide variety of plants used for medicine and food1). Polyphenols are known to form a stable complex with human whole saliva2). They form a complex with proline-rich glycoproteins and histatins3-5). Human saliva is a tannin-binding agent, similar to gelatin, bovine serum albumin (BSA), lysozyme and polyvinylpyrrolidine (PVP)6,7). Therefore, it is expected that the salivary interaction with saliva-soluble and saliva-precipitable tannin may influence oral calcification. Both glycyrrhiza (a herb) and tannic acid affected the formation of calcium phosphate precipitates8). Tannic acid forms precipitates with saliva (salivaprecipitable), but glycyrrhiza does not (salivasoluble)9). Therefore, it is of interest to study the effects of both compounds on the formation of calcium phosphate precipitates in the presence of saliva. Materials and Methods
マイクロフォーカスX線CT法 (μCT法) は, 複数の構成要素からなる顎関節のような組織構造を解析するのに有効な観察法である. われわれは, マウス発生・成長・加齢に伴う顎関節の構造・組織上の変化を包括的にとらえることを長期的課題として, 今回の報告ではマウス下顎頭の成長と加齢に伴う形態構造上の変化に注目した. 観察試料として, 生後1日から90週齢までのICRマウス顎関節を用いた. 動物週齢に伴う顎関節の成長発育については, μCT画像に基づき下顎頭を中心とした顎顔面骨の形態計測を行った. マウス顎関節の形態計測の結果から, 10週齢までの成長期と, その後の50週齢までの構造上の変化が少ない成熟期に区別できた. 下顎頭の骨構造解析では, この成長期から成熟期への移行に際して, 比表面積 (骨表面積/骨量) や骨梁幅に著明な変化を伴うことが確かめられた. 50週齢を越えたマウスの下顎頭では, 頭頂部中央の骨質の損耗と周辺部での過形成による変形が顕著となった. 顎関節の脱灰薄切標本での組織観察から, 50週齢を越える高齢マウスの下顎頭軟骨においては, 骨質の損耗を補填するように軟骨細胞の増生をきたすことも確かめられた. 以上の観察結果から, 成長を遂げた下顎頭においても, 軟骨細胞の増殖や基質産生を調節することにより, 咬合圧やストレスに対して大きな適応能を保持していることが支持された.
う蝕および加齢がラット肺組織の病理組織学的変化に及ぼす影響を調べた. 10週間Diet 2000で飼育したラットは, 通常の粉末飼料で飼育した対照ラットに比べて, 著しく臼歯裂溝部にう蝕が認められた. さらに, う蝕に罹患の後, 20カ月間通常の粉末飼料で飼育を続けた高齢う蝕罹患ラットの肺組織を, 病理組織学的に検索を加えた結果, 好中球あるいはリンパ球などによる肺胞内滲出が小葉単位に起こる気管支肺炎の像を呈していた. さらに, 吸引された菌塊, 気道分泌物, 多数の組織球の集簇や異物型巨細胞などが観察された. 一方, 通常の粉末飼料で20カ月10週間飼育された対照ラットの肺組織には, 胸膜および肺胞壁の線維性肥厚や肺気腫などの加齢変化はみられたものの, 炎症像が認められなかった. 本結果から, 本実験モデルは口腔内常在細菌の不顕性誤嚥が肺炎の原因であることを, 改めて実験的に証明したといえる.
口蓋裂患者では, 幼少期にpush back法による口蓋形成手術が広く行われているが, 術後の瘢痕組織が上顎骨の成長を抑制すると報告されている. 本研究では, 実験的に生後20日齢ラットの口蓋粘膜を一部除去して瘢痕形成を行い, 術後6週経過時に口蓋粘膜の病理組織学的検索および口蓋骨表面の走査電顕的検索を行った. 対照群の口蓋粘膜は, 角化重層扁平上皮, 上皮下の線維性結合組織よりなり, 口蓋骨面には骨膜がみられた. 実験群では, 不規則な角化重層扁平上皮とその直下に瘢痕性結合組織がみられ, 骨膜はみられなかった. 走査電顕像では, 対照群に比べて細動静脈孔が減少しており, また骨表面の粗 化と骨基質の膠原線維束の不明瞭化が認められた. 以上より, 術後の瘢痕形成は骨への栄養供給の低下とともに, 口蓋骨の成長に影響を与えることが示唆された.
本研究では, 免疫組織化学方法により, Ras/Raf/MEK/ERKのシグナル伝達経路にあるH-rasおよびpERK 1/2タンパク質の過剰発現, および活性化と口腔扁平上皮癌の転移との関連性について検討した. 口腔扁平上皮癌38症例と正常口腔粘膜上皮17例, 合計55症例を検索対象とした. 口腔扁平上皮癌症例においては, H-rasとpERK 1/2タンパクの発現は, 正常口腔粘膜上皮より高頻度である傾向が認められた (p<0.01). pERK 1/2タンパクの高レベルの発現は, 癌組織の組織分化度が低いことと有意の相関性があった (p<0.05). H-rasとpERK 1/2タンパクの発現は, 腫瘍胞巣の大小および臨床的ステージとは関連性がないことが示された (p>0.05). H-rasタンパクの高レベルの発現は, リンパ節転移の有無と有意の関連性があり (p<0.05), リンパ節転移を伴った症例では, H-ras, pERK 1/2のおのおのの単独の発現と比べ, H-rasとpERK 1/2タンパクの共通発現の亢進が高度で, H-rasとpERK 1/2タンパクの両者の発現を示すものが多かった (p<0.05). このことから, Ras/Raf/MEK/ERKのシグナル伝達経路にあるH-ras, pERK 1/2のタンパク質発現は, 口腔扁平上皮癌の悪性度の指標である腫瘍の転移や組織分化度と相関する大きな意義を有していることが示唆された.
In the present study, we aimed to investigate changes in the mineral composition and solubility of rat bone under various regimens of fluoride administration in drinking water. Sprague-Dawley rats (male, 4-week-old at the beginning of fluoride administration) were used. We adopted two animal-housing protocols: (1) the age-matched animals were given 0ppm (control) or 50ppm fluoride as NaF in deionized water for various periods ranging from 2 to 16 weeks, and (2) the animals were housed for 10 weeks under fluoride regimens of 0 (control), 10, 30, 50, 70 or 90ppm. At the end of fluoride administration, the animals were sacrificed and then the diaphysial cortical bones of the femora and tibia were harvested. All bone samples were pulverized and deproteinated by low-temperature ashing prior to use in solubility measure-ments. The solubility of bone crystals was determined through a series of selid/solution equilibration at 25°C under 1.8% CO2/N2 gas environment. The results obtained showed that bone mineral composition was highly sensitive to the ingested fluoride, increasing the fluoridation degree of bone crystals up to a plateau around 1 wt%, i. e., one third of the theoretical content for fluorapatite. From the solubility data of bone samples collected according to both animal-housing protocols, it was proved that bone crystal solubility improved most substantially during the initial 6 weeks of fluoride administration and in the concentration range lower than 30-ppm fluoride in the drinking water. Further improvement of the solubility was only modest in magnitude (as indicated by changes in solubility product) even after fluoride ingestion over longer administration periods or at concentrations of 50-90ppm fluoride.
本研究では, 生後8カ月から14カ月の期間にNaF含有飲料水 (2mgF/kg体重/day) を与えたブタ (および, 同期間にわたり脱イオン水を摂飲した対照群動物) を対象として, フッ素の長期経口投与による骨の化学組成, 結晶性, 骨結晶の熱力学的な溶解度への影響を検討した. 観察試料として, 大腿骨骨幹部皮質骨と腰椎海綿骨の粉末試料を作成した. 骨試料の分析には, 顕微X線法と形態計測, X線回折法, FTIR, EPMA, 固相試料と溶液試料の化学分析を併用し, 骨結晶の溶解度測定は25℃, 1.8%CO-54分圧下で行った. 今回の実験結果から, 実験群動物の皮質骨でのF含有量は対照群に比べて一桁高く, 皮質骨と海綿骨とを比べると, 対照群・実験群ともに海綿骨で約2倍程度にまで濃縮されていたが, 組織学的には有意の差は検出されなかった. X線回折線の半値幅の測定から, 両群試料の間でc軸方向の結晶性には有意な差はなかったが, 実験群皮質骨試料ではa, b軸方向での結晶性の向上が認められた. 骨結晶の溶解度に関して, ハイドロキシアパタイトの化学組成式に従った平衡時の溶液相でのイオン活量積として表すと, 対照群試料では皮質骨と海綿骨を問わず10-53から5×10-53, 実験群試料では一桁下がった10-54から5×10-54の範囲の値が得られた.
In response to injury, dental pulp cells differentiate into odontoblast-like cells to produce reparative dentin. To understand the mechanism of odontoblastic differentiation and to stimulate reparative dentin formation, we developed an in vitro culture system representing odontoblastic differentiation of bovine dental pulp cells and profiled the protein expression through proteomic analyses. Fractionation with which two-dimensional gel electrophoresis exhibited an analogous protein expression pattern between in vivo and in vivo pulp cells, but underlined differentially expressed proteins during the odontoblastic differentiation. Subsequent mass spectrometry and NH2-terminal amino acid sequence demonstrated degradation of vimentin into several species, up-regulation of connexin 43 and down-regulation of protein disulfide isomerase in the differentiating pulp cells and suggests the involvement of these proteins in odontoblastic differentiation.
Streptozotocin-induced diabetic mice displayed a significantly lower mechanical nociceptive threshold than age-matched control mice. In centrast, there was no difference between diabetic mice and control mice in thermal nociceptive threshold. Intrathecal (i. t.) administration of ω-agatoxin IVA (0.33-10 pmol/mouse), a selective blocker of P/Q-type voltage-dependent calcium channels (VDCCs), produced dosedependent inhibition of the mechanical nociceptive response, and its antinociceptive effect at lower doses was greater in diabetic mice than in control mice. The antinociceptive effects of an N-type blocker ω-conotoxin GVIA (0.33-10pmol/mouse, i. t.) and an L-type blocker calciseptine (1-10pmol/mouse, i. t.) were both slightly, but not significantly greater in mice receiving streptozotocin. The antinociception of intrathecal morphine was not different between the experimental groups. Our results indicate that a selective alteration in the role of P/Q-type channels may occur in the spinal processing of mechanic l hypersensitivity in diabetic mice.
Receptor activator of NF-kB (RANK) and its ligand, receptor activator of NF-kB ligand (RANKL) play a crucial role in the differentiation and activation of osteoclasts. In order to evaluate the efficacy of RANK, we designed a soluble murine RANK (sRANK) and compared its functional activitywith Osteoprotegerin (OPG), a soluble decoy receptor for RANKL. sRANK was expressed in baculovirus-infected Sf-9 cells and purified by Ni-NTA chromatography followed by MonoQ column elution. The binding affinity of the purified sRANK to RANKL was quite similar to that of OPG. Furthermore, the inhibitory effect on RANKL-induced osteoclastogenesis from mouse bone marrow cells showed no significant difference between sRANK and OPG. However, sRANK had no effect on TNF-related apoptosisinducing ligand (TRAIL) -induced apoptosis, although OPG prevented the cytotoxic activity of TRAIL. The results of this study suggest that recombinant sRANK may have therapeutic value as an inhibitor of bone resorption.
The Ebk/MDK1 gene belongs to the receptor tyrosine kinase (RTKs) family and has been shown to be closely related to the Eph/Eck/Elk subfamily. A study was conducted to investigate the role of Ebk/ MDK1 in the oral development of early mouse embryogenesis. RT-PCR analysis identified the presence of Ebk/MDK1 mRNA in the region of the first molar at embryonic day 15 (E15). In situ hybridization analysis in the developing oral field from E12 to E16 revealed Ebk/MDK1 expressed in the mesenchyme underlying the dental epithelium of both of the first molars and incisors, as well as in the mesenchyme of the developing alveolar ridge, palate, tongue and lip. The distinct patterns of Ebk/MDK1 expression suggest that this gene may be involved in the establishment of these oral structures in mouse embryogenesis.
一歯のみに外傷性咬合を引き起こしたときの顎関節の組織変化について明らかにすることを目的に, 次の実験を行った. 7週齢の雄性Wistar系ラットを用い, 上顎左側第一臼歯の咬合面にレジンを2mm築盛し, 外傷性咬合を付与した. レジンを築盛した群を実験群とし, 左側を処置側, 右側を無処置側とし, 無処置の群を対照群とした. 実験期間は外傷性咬合付与後3日から56日で, 通法に従い前頭断連続切片標本を作製し, 顎関節の変化について, 組織学的ならびに組織計量学的に比較検討した. 下顎頭では実験側, 無処置側ともに7日後に軟骨層で萎縮性の変化がみられたが, その後BrdU陽性細胞数の増加や軟骨層の肥厚がみられ, これらの値は対照群と比較して高値で, 14日目には最大値を示し, 28日後では対照群と同様の組織像を示した. 以上の所見より, 一歯のみの外傷性咬合の場合, 下顎頭の変化には両側で同様の組織学的変化が生じることが明らかになった.
To study which physical properties of a food bolus trigger swallowing during mastication of gelatinous food, we measured the texture of a bolus immediately prior to swallowing by texture profileanalysis. Filter paper soaked in 0.2M tartaric acid (acid stimulation) or distilled water (DW stimulation) was placed on the dorsal surface of the tongue of 10 healthy adult participants for 1 minute before they masticated rice cake (RC) or gummy candy (G). The G bolus was significantly (p<0.05) harder immediately prior to swallowing after acid stimulation than after DW stimulatien. On the other hand, hardness, adhesive. ness and cohesiveness of the RC bolus did not differ significantly between the two masticatory conditions (after acid stimulation and DW stimulation). After DW stimulation, the texture of the RC bolus during the middle stage of mastication was compared with that just before swallowing. The RC bolus at the middle stage was significantly harder (p<0.001) and more adhesive (p<0.05) than just before swallowing. These results suggest that the degree of adhesiveness of a bolus might be closely related to the swallowing threshold for gelatinous food such as rice cakes.
To determine whether clenbuterol, a β2-adrenergic agonist, affects the mass and fiber type of the mouse masseter muscle by altering the expressions of insulin-like growth factors (IGFs), their receptors (IGFRs), and their binding proteins (IGFBPs), we analyzed changes in the myofiber diameter, the expressions of myosin heavy chain (MHC) mRNAs, the markers for muscle fiber type, and the expressions of IGF, IGFR, and IGFBP mRNAs. In addition, to identify a possible contribution of muscle satellite cells in the change of the mouse masseter induced by clenbuterol, we analyzed the expressions of the myoD family (myf5, myoD, myogenin, and MRF4) and myocyte nuclear factor (MNF) mRNAs, and performed immunolocalization for proliferating cell nuclear antigen (PCNA), because they are all markers for activated and quiescent satellite cells. Clenbuterol (40 μg/ml) was orally administered to 6-month-old mice via their drinking water for 2 weeks. The relative amounts of mRNAs were analyzed by competitive polymerase chain r action in combination with reverse-transcription. The administration of clenbuterol increased the myofiber diameter by 26% (p<0.001), but it did not significantly change the amounts of MHC mRNAs, suggesting that clenbuterol induced hypertrophy but did not alter the fiber type. The administration of clenbuterol increased the amount of mRNA for IGF-I by 219% (p<0.05), but it decreased that for IGFBP3 by 21% (p<0.001). The amounts of mRNAs for all genes except for IGF-I and IGFBP3, and the immunolocalization for PCNA were not significantly changed by clenbuterol. These results suggest that clenbuterol induces hypertrophy in the mouse masseter muscle and that IGF-I and IGFBP3 are involved in the clenbuterol-induced hypertrophy, but the satellite cells might not be involved.
