The human growth hormone genes (hGH) are located on chromosome 17q22-24. A tandem repeat linked to hGH is highly polymorphic and the basic structure of the repeat is reported to be (AAAG)₃ACAA(AG)₃[(AAAG)_x(AG)_y(AAAG)_z]AAGG (AAAG)₃ in Caucasians, but details of allelic structure have not been clarified in Japanese. The objective of this study was to provide the initial data of the hGH alleles and the structure of the tandem repeat in Japanese. In this study, the sequences of hGH alleles were analyzed in 56 healthy, unrelated Japanese. A total of 57 alleles were found and the degree of heterozygosity was 96.4%, however, 2 samples could not be sequenced. Our results provide the basic data of the hGH alleles in Japanese and point out the future improvement for forensic analysis of this locus.

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The purposes of this study were to examine the differences in masticatory function of children with different dental stages when they chew pieces of chewing gum with various volume and hardness, and to examine the relationships of the number of chewing strokes to masticatory efficiency as well as maximum bite force. Forty-six children (7.9±2.4 years old) and eleven adults (28.5±7.1 years old) participated in this study. The subjects chewed three pieces of colorchangeable chewing gum with different volumes and one piece of hard gum and the number of chewing strokes per minute, masticatory efficiency, and maximum bite force were determined. It was concluded that the ‘adaptability’ of masticatory function of children to the different volume and hardness increased with the development. Significant correlation was found between the ratio of the number of chewing strokes in hard gum chewing to that in soft gum chewing and the maximum bite force of children with deciduous dentition

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Anterior cingulate cortex (ACC) plays an important role in human volition, but its function in swallowing is not well known. We tested the hypothesis that visual inputs given before volitional swallowing modulate the ACC activity. We evaluated the relationship between visual effect on swallowing “behavior” and “brain activity” using EMG (electromyography) and fMRI (functional magnetic resonance imaging). Seven healthy volunteers participated in the EMG study, and 10 volunteers in the fMRI study. Visual images, i.e., photographs of food (DRINK) or general items (GENERAL), were used as the visual input and these were provided with (WS) or without (DS) water. Both behavioral and brain activity data were recorded during each trial in four (DRINK/WS, GENERAL/WS, DRINK/DS, GENERAL/DS) conditions. EMG study showed that the latency was significantly shorter with DRINK input than that with GENERAL input in the WS condition. Meanwhile, in the fMRI study, the maximum MR signal change was greater with GENERAL than that with DRINK in both WS and DS conditions. Thus, it appears that there was a relationship between swallowing behavior and the ACC activity in volitional swallowing

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The aim of the present study was to investigate the extent to which oral streptococci or lactic acid producing bacteria are able to regulate pH value, especially at low pH values associated with dentinal carious activity using a PCR method. One millimeter- thick sections were sliced from 24 extracted carious human molars. The pH values on the tooth sections were evaluated using a pH-imaging microscope. A dentin sample (1×1×1mm) was prepared from the areas with the lowest or highest pH and homogenized to extract bacterial genomic DNA. Specific primers were used for nested PCR to mutans streptococci (MS: Streptococcus mutans and Streptococcus sobrinus). Conserved primers were also used for PCR to lactobacilli and gram positive bacteria. The PCR products were separated by electrophoresis, and then oral bacteria were identified. There was no significant difference between carious and intact dentin in MS identification. However, the frequency of the product amplified by the conserved primers in carious dentin (16/24, 66.7%) was significantly higher than that in intact dentin (2/24, 8.3%), and PCR products demonstrated, by sequence analysis, various bacteria, including oral streptococci. It was concluded that oral streptococci may be associated with the development of “low pH-carious dentin”.

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