Shouji Hironaka

Relationship between swallowing function and the skeletal muscle mass of older adults requiring long-term care.

The present study investigated the risk factors for dysphagia among older adults who require long‐term care, and also examined their systemic decrease in skeletal muscle mass.

Characteristics of and weaning strategies in tube‐dependent children

Despite resolution of the symptoms of eating and/or swallowing disorders, prolonged tube feeding is maintained in some children. This study summarized the characteristics of children with tube dependence and investigated the causes of tube dependence.

Relationship between Skeletal Muscle Mass and Swallowing Function in Patients with Alzheimer’s Disease.

The present study verified the hypothesis that decreased skeletal muscle in older adults with Alzheimers disease is related to Alzheimers disease progression and decreased oral or swallowing function.

Effects of lactoferrin and lactoperoxidase‐containing food on the oral hygiene status of older individuals: A randomized, double blinded, placebo‐controlled clinical trial

Lactoferrin and lactoperoxidase have antimicrobial effects against oral pathogens. This randomized, double‐blinded, placebo‐controlled parallel group study tested the efficacy of a lactoferrin and lactoperoxidase‐containing tablet (LF + LPO tablet) in improving the oral hygiene status of older individuals.

Inactivating effects of the lactoperoxidase system on bacterial lyases involved in oral malodour production.

The main components of oral malodour have been identified as volatile sulfur compounds (VSCs), including hydrogen sulfide (H(2)S) and methyl mercaptan (CH(3)SH). The lactoperoxidase (LPO) system (consisting of LPO, glucose oxidase, glucose and thiocyanate) was previously shown to exhibit antimicrobial activities against some oral bacteria in vitro and suppressive effects on VSCs in mouth air in a clinical trial. Here, we examined the in vitro effects of the LPO system on the activities of the bacterial lyases involved in the production of VSCs by oral anaerobes. The exposure of crude bacterial extracts of Fusobacterium nucleatum and Porphyromonas gingivalis or purified methionine γ-lyase to the LPO system resulted in the inactivation of their lyase activities through l-cysteine and l-methionine, which was linked to the production of H(2)S and CH(3)SH, respectively. The exposure of living F. nucleatum and P. gingivalis cells to the LPO system resulted in the suppression of cell numbers and lyase activities. The inactivation of the crude bacterial extracts of F. nucleatum and purified methionine γ-lyase by the LPO system was partly recovered by the addition of DTT. Therefore, the LPO system may inactivate bacterial lyases including methionine γ-lyase by reacting with the free cysteine residues of lyases. These results suggested that the LPO system suppresses the production of VSCs not only through its antimicrobial effects, but also by its inactivating effects on the bacterial lyases of F. nucleatum and P. gingivalis.

Orosensory deprivation alters taste-elicited c-Fos expression in the parabrachial nucleus of neonatal rats

In the present study we examined the effects of neonatal orosensory deprivation on taste-elicited gustatory activity in the rat parabrachial nucleus (PBN) using the functional anatomical marker c-Fos. Animals in three groups (GG, GO and GM) received gastric cannula implantation surgery on postnatal day 9 (P9). Animals in the fourth group (MR) did not receive any surgery. GG rats were fed by infusion of artificial milk directly into the stomach. GO rats were fed by intraoral infusion of artificial milk. GM and MR rats were reared by their mother with free access to mothers milk, water and rat chow. Rats from all groups were similar in body weight and length by P21. On P21 rats in all groups were intraorally presented with 0.5M sucrose solution and the brains were extracted and processed for c-Fos immunohistochemistry. Taste-elicited c-Fos expression in both the gustatory waist area, and the external lateral subnucleus of the PBN in rats in the GG group was significantly more robust than in the other three groups. These findings suggest a substantial alteration in orosensory-evoked neuronal response in this nucleus, due to sensory or motor deprivation during a critical developmental stage.

Effects of gum chewing exercises on saliva secretion and occlusal force in community-dwelling elderly individuals: A pilot study

Elderly individuals face the risk of reductions in saliva secretion and occlusal force caused by systemic diseases or medications that can eventually result in malnutrition and systemic complications. We tested the hypothesis that regular gum chewing exercises (GCE) would enhance saliva secretion and occlusal force in an elderly population.

Examination of factors affecting the intraoral perception of object size: a preliminary study

Oral sensory function is essential for the successful performance of a range of ingestion. Although the perception of object size is important in determining the degree of manipulation, evidence suggests that people does not always perceive the size of the object in oral cavity accurately. The purpose of this study was to investigate the factors affecting the intraoral perception of object size. Twenty-three healthy young volunteers detected the size of cylinders inserted into oral cavity blindly and identified it from the reference set. The diameter of cross section varied from 10 to 14 mm in a gap of 1 mm and had three different temperatures (5, 36, 50 °C) in each. The perceived size was recorded, and the difference with the actual size was assessed. The required time for identification was also measured and compared between gender and between temperatures. The results demonstrated that the direction of size illusion was significantly affected by the required time for identification. Long manipulation led to overestimation, and short manipulation led to underestimation of object size irrespective of temperature and size. Gender was the other factor affecting intraoral size perception. The rate of overestimation was low in female participants comparing with male participants in this experiment, although the number of participants was limited. We therefore concluded that in order to detect the other factors affecting intraoral size perception, regulating oral manipulation time is indispensable.

Effects of lactoferrin and lactoperoxidase-containing food on the oral microbiota of older individuals

The oral microbiota influences health and disease states. Some gram‐negative anaerobic bacteria play important roles in tissue destruction associated with periodontal disease. Lactoferrin (LF) and lactoperoxidase (LPO) are antimicrobial proteins found in saliva; however, their influence on the whole oral microbiota currently remains unknown. In this randomized, double‐blinded, placebo‐controlled study, the effects of long‐term ingestion of LF and LPO‐containing tablets on the microbiota of supragingival plaque and tongue coating were assessed. Forty‐six older individuals ingested placebo or test tablets after every meal for 8 weeks. The relative abundance of bacterial species was assessed by 16S rRNA gene high‐throughput sequencing. Most of the bacterial species in supragingival plaque and tongue coating that exhibited significant decreases in the test group were gram‐negative bacteria, including periodontal pathogens. Decreases in the total relative abundance of gram‐negative organisms in supragingival plaque and tongue coating correlated with improvements in assessed variables related to oral health, such as oral malodor and plaque accumulation. Furthermore, there was significantly less microbiota diversity in supragingival plaque at 8 weeks in the test group than in the placebo group and low microbiota diversity correlated with improvements in assessed variables related to oral health. These results suggest that LF and LPO‐containing tablets promote a shift from a highly diverse and gram‐negative‐dominated to a gram‐positive‐dominated community in the microbiota of supragingival plaque and tongue coating. This microbial shift may contribute to improvements in oral health, including oral malodor and state of the gingiva.

Effects of lactoferrin and lactoperoxidase-containing food on the oral microbiota in the elderly

The oral microbiota influences health and disease states. Some gram‐negative anaerobic bacteria play important roles in tissue destruction associated with periodontal disease. Lactoferrin (LF) and lactoperoxidase (LPO) are antimicrobial proteins found in saliva; however, their influence on the whole oral microbiota currently remains unknown. In this randomized, double‐blinded, placebo‐controlled study, the effects of long‐term ingestion of LF and LPO‐containing tablets on the microbiota of supragingival plaque and tongue coating were assessed. Forty‐six older individuals ingested placebo or test tablets after every meal for 8 weeks. The relative abundance of bacterial species was assessed by 16S rRNA gene high‐throughput sequencing. Most of the bacterial species in supragingival plaque and tongue coating that exhibited significant decreases in the test group were gram‐negative bacteria, including periodontal pathogens. Decreases in the total relative abundance of gram‐negative organisms in supragingival plaque and tongue coating correlated with improvements in assessed variables related to oral health, such as oral malodor and plaque accumulation. Furthermore, there was significantly less microbiota diversity in supragingival plaque at 8 weeks in the test group than in the placebo group and low microbiota diversity correlated with improvements in assessed variables related to oral health. These results suggest that LF and LPO‐containing tablets promote a shift from a highly diverse and gram‐negative‐dominated to a gram‐positive‐dominated community in the microbiota of supragingival plaque and tongue coating. This microbial shift may contribute to improvements in oral health, including oral malodor and state of the gingiva.