Akira Katakura

Detecting early oral cancer: narrowband imaging system observation of the oral mucosa microvasculature

The aim of this study was to analyze and describe the intrapapillary capillary loops (IPCL), which are a feature of early oral neoplastic lesions, using a narrowband imaging (NBI) system. Forty-one patients (26 men, 15 women; mean age, 52.34 years; range, 23-83 years) presenting with non-neoplastic or neoplastic lesions, and normal cases, were examined using the prototype Evis Lucera Spectrum (Olympus Co.). The images were analyzed and an IPCL classification was devised. All normal cases (n=10) had regularly distributed capillary loops of the same shape (type I). Non-neoplastic lesions (n=8) had mild changes of the capillary loops (types II and III) and neoplastic lesions (n=23) were irregularly distributed and had several loop shapes (types III and IV). The microvascular organization of non-neoplastic lesions was notably different from that of neoplastic lesions. A brownish area was found in five cases of early carcinoma. The narrowband imaging system is a potential approach for clinically analyzing microvascular organization and IPCL. It could be useful for diagnosing oral squamous cell carcinoma at an earlier stage and for determining the margin of resection.

Helicobacter pylori May Have Only a Transient Presence in the Oral Cavity and on the Surface of Oral Cancer

We used the reverse transcription polymerase chain reaction (RT‐PCR) and culture methods to study the presence of Helicobacter pylori in the gastric and oral samples from a total of 116 gastritis and peptic ulcer patients, including 58 with oral cancer. Detection rates of H. pylori were 46.6% in stomach samples and 12.1 % in oral swab samples. All of the oral cancer surface swab samples were positive for H. pylori, as were their gastric samples suggesting that oral H. pylori derived from the stomach. The culture supernatants of Streptococcus mutans and Prevotella intermedia inhibited the growth of the H. pylori strain and caused the formation of the coccal form. In cases where H. pylori was detected in the oral cavity samples, including the oral cancer surface samples, it was believed that this species had colonized the stomach and were present in the oral cavity only as a transient organism.

Odontoblasts as sensory receptors: transient receptor potential channels, pannexin-1, and ionotropic ATP receptors mediate intercellular odontoblast-neuron signal transduction.

Various stimuli induce pain when applied to the surface of exposed dentin. However, the mechanisms underlying dentinal pain remain unclear. We investigated intercellular signal transduction between odontoblasts and trigeminal ganglion (TG) neurons following direct mechanical stimulation of odontoblasts. Mechanical stimulation of single odontoblasts increased the intracellular free calcium concentration ([Ca2+]i) by activating the mechanosensitive-transient receptor potential (TRP) channels TRPV1, TRPV2, TRPV4, and TRPA1, but not TRPM8 channels. In cocultures of odontoblasts and TG neurons, increases in [Ca2+]i were observed not only in mechanically stimulated odontoblasts, but also in neighboring odontoblasts and TG neurons. These increases in [Ca2+]i were abolished in the absence of extracellular Ca2+ and in the presence of mechanosensitive TRP channel antagonists. A pannexin-1 (ATP-permeable channel) inhibitor and ATP-degrading enzyme abolished the increases in [Ca2+]i in neighboring odontoblasts and TG neurons, but not in the stimulated odontoblasts. G-protein-coupled P2Y nucleotide receptor antagonists also inhibited the increases in [Ca2+]i. An ionotropic ATP (P2X3) receptor antagonist inhibited the increase in [Ca2+]i in neighboring TG neurons, but not in stimulated or neighboring odontoblasts. During mechanical stimulation of single odontoblasts, a connexin-43 blocker did not have any effects on the [Ca2+]i responses observed in any of the cells. These results indicate that ATP, released from mechanically stimulated odontoblasts via pannexin-1 in response to TRP channel activation, transmits a signal to P2X3 receptors on TG neurons. We suggest that odontoblasts are sensory receptor cells and that ATP released from odontoblasts functions as a neurotransmitter in the sensory transduction sequence for dentinal pain.

Relationship between chewing ability and sarcopenia in Japanese community-dwelling older adults.

It has been reported that if nutrient intake is unbalanced, muscle mass, muscle strength and physical performance declines, and therefore it is important to maintain chewing ability to keep a balanced nutrient intake. However, the relationship between chewing ability and sarcopenia has not been previously reported. Therefore, the present study investigated the relationship between chewing ability and sarcopenia in addition to known sarcopenia‐related factors.

Detecting signs of dysphagia in patients with Alzheimer's disease with oral feeding in daily life

It is important to understand dysphagia in patients with dementia, as it is associated with malnutrition and aspiration pneumonia. Particularly in patients with Alzheimers disease (AD), mortality from pneumonia is high and accounts for 70% of the causes of death. However, the standard swallowing tests are often difficult to use for patients with dementia, and methods to assess daily swallowing function are required. Therefore, the purpose of the present study was to identify signs of dysphagia in AD patients in daily life.

Changes in the Homeostatic Mechanism of Dental Pulp with Age: Expression of the Core-binding Factor Alpha-1, Dentin Sialoprotein, Vascular Endothelial Growth Factor, and Heat Shock Protein 27 Messenger RNAs

Dental pulp has various characteristics in the pulp chamber, but only a few biological evaluations about the effect of age on dental pulp tissue have been reported. The purpose of this study was to compare dental pulp from young and adult rats to characterize the homeostatic mechanism. Dental pulp cells (DPCs) were obtained from the first molar of rats, weighing 150 g each for the young group and 350 g each for the adult group. The expression of core-binding factor alpha-1 (Cbfa-1), vascular endothelial growth factor (VEGF), or heat shock protein (HSP) 27 messenger RNAs (mRNAs) by cultured pulp cells was determined by using a quantitative real-time PCR system after 3, 7, or 14 days. The expression of Cbfa-1 mRNA in the young group was higher than in the adult group. Expression of VEGF and HSP27 mRNAs in the adult group was higher than in the young group. The self-defense system in young DPCs is undertaken by calcification, but in adult DPCs it is carried out by the expression of self-defense proteins and the regeneration of vessels.

Intercellular signal communication among odontoblasts and trigeminal ganglion neurons via glutamate.

Various stimuli to the exposed surface of dentin induce changes in the hydrodynamic force inside the dentinal tubules resulting in dentinal pain. Recent evidences indicate that mechano-sensor channels, such as the transient receptor potential channels, in odontoblasts receive these hydrodynamic forces and trigger the release of ATP to the pulpal neurons, to generate dentinal pain. A recent study, however, has shown that odontoblasts also express glutamate receptors (GluRs). This implies that cells in the dental pulp tissue have the ability to release glutamate, which acts as a functional intercellular mediator to establish inter-odontoblast and odontoblast-trigeminal ganglion (TG) neuron signal communication. To investigate the intercellular signal communication, we applied mechanical stimulation to odontoblasts and measured the intracellular free Ca2+ concentration ([Ca2+]i). During mechanical stimulation in the presence of extracellular Ca2+, we observed a transient [Ca2+]i increase not only in single stimulated odontoblasts, but also in adjacent odontoblasts. We could not observe these responses in the absence of extracellular Ca2+. [Ca2+]i increases in the neighboring odontoblasts during mechanical stimulation of single odontoblasts were inhibited by antagonists of metabotropic glutamate receptors (mGluRs) as well as glutamate-permeable anion channels. In the odontoblast-TG neuron coculture, we observed an increase in [Ca2+]i in the stimulated odontoblasts and TG neurons, in response to direct mechanical stimulation of single odontoblasts. These [Ca2+]i increases in the neighboring TG neurons were inhibited by antagonists for mGluRs. The [Ca2+]i increases in the stimulated odontoblasts were also inhibited by mGluRs antagonists. We further confirmed that the odontoblasts express group I, II, and III mGluRs. However, we could not record any currents evoked from odontoblasts near the mechanically stimulated odontoblast, with or without extracellular Mg2+, indicating that N-methyl-d-aspartic acid receptor does not contribute to inter-odontoblast signal communication. The results suggest that a mechanically stimulated odontoblast is capable of releasing glutamate into the extracellular space via glutamate-permeable anion channels. The released glutamate activates mGluRs on the odontoblasts in an autocrine/paracrine manner, forming an inter-odontoblasts communication, which drives dentin formation via odontoblast-odontoblast signal communication. Glutamate and mGluRs also mediate neurotransmission between the odontoblasts and neurons in the dental pulp to modulate sensory signal transmission for dentinal sensitivity.

An examination of factors related to aspiration and silent aspiration in older adults requiring long-term care in rural Japan.

Swallowing disorders are a growing problem among the elderly in long-term care (LTC), and they can cause aspiration pneumonia. In order to detect swallowing disorders early, simple tools are needed to assess aspiration and silent aspiration (SA). To compile a sample of elderly people requiring LTC, and categorise them as having suspected aspiration and/or SA using simple screening tools. In addition, oral ability, severity of dementia, vital functions and nutritional status were compared in these groups. A total of 393 elderly people in LTC (89 men and 304 women; age ranging from 65 to 100 years) were included in the study. The modified water swallow test, cervical auscultation and cough test were used to assess swallowing function. The participants were categorised as having suspected aspiration and/or SA, and the following assessments were performed: (i) oral ability (lips function, tongue function, rinsing and gargling ability), (ii) dementia severity, (iii) vital functions and (iv) nutritional status. Suspected aspiration was apparent in 50.5% of patients, of which 24.0% had suspected SA. Those with suspected aspiration showed worsened oral ability, dementia severity, vital functions and nutritional status. Similarly, those with suspected SA showed worsened dementia severity, vital functions and nutritional status. Logistic regression analysis revealed that lip closure, lingual movement and rinsing ability were significantly associated with suspected aspiration. Dementia severity was the best predictor of suspected SA. Simple screening tools can be used to identify suspected aspiration and SA, which may facilitate early detection of aspiration pneumonia or swallowing disorder risk.

The antihistamine olopatadine regulates T cell activation in palladium allergy.

Because of its corrosion resistance palladium (Pd) has been widely used in many consumer products ranging from fashion accessories to dental materials. Recently, however, an increase in Pd allergy cases has been reported. Metal allergy is categorized as a Type IV allergy, which is characterized as a delayed-type hypersensitivity reaction in which T cells are known to play an important role; however, the precise mechanism of their action remains unclear. Here we defined the relationship between histamine and the Pd allergic reaction specifically with respect to T cell responses. To verify the effects of histamine on T cells, we examined whether there is a change in IFN-γ production following stimulation of histamine or the antihistamine, olopatadine hydrochloride (OLP), in vitro. In addition, we assessed whether OLP administration affected the degree of footpad swelling or IFN-γ production during the Pd allergy response in mice. We found that histamine stimulation increased IFN-γ production in T cells, specifically enhancing IFN-γ production in CD8(+) T cells compared with CD4(+) T cells. Interestingly, OLP suppressed the production of IFN-γ in CD8(+) T cells, and this compound inhibited footpad swelling and IFN-γ production in mice with Pd allergy. These results suggest that histamine promotes the Type IV allergic reaction and thus, the histamine 1 receptor (H1R) might be useful therapeutic target for treatment of metal allergy.

Evaluation of Superficial Oral Squamous Cell Malignancy Based on Morphometry and Immunoexpression of Cytokeratin 13 and Cytokeratin 17

Objective: Evaluation of combined morphometry and immunoexpression of cytokeratin 13 (CK13) and cytokeratin 17 (CK17) for cytological identification of superficial oral squamous cells. Study Design: Smears from 11 tongue squamous cell carcinoma patients were processed by liquid-based cytology, stained via the Papanicolaou method and divided into multiple specimens by cell transfer. Morphometric indices, including nuclear area, nuclear perimeter, nuclear circular rate, largest-to-smallest dimension ratio of the nucleus and nucleocytoplasmic ratio, were measured using a computerized analysis system. CK13 and CK17 were detected by immunostaining. Morphometric values were compared between cell populations with distinct staining and immunoexpression patterns. Results: Most orange G-stained superficial cells were negative for CK13 (99.4%) and CK17 (98.6%). For light green-stained superficial cells, loss of CK13 was associated with greater cellular atypia in the nuclear area, nuclear perimeter and nucleocytoplasmic ratio (p < 0.01), while expression of CK17 was related to higher-grade cellular atypia in the same parameters (p < 0.01) as well as the nuclear circular rate (p < 0.05). Conclusion: Immunoexpression of CK13 and CK17 in light green-stained superficial cells was associated with more severe morphological atypia. Combined morphometry and immunoexpression of CK13 and CK17 might be useful for cytological diagnosis of this cell population.