ABSTRACT
BACKGROUND: Taste loss is a major cause of morbidity in patients undergoing head and neck irradiation. METHODS: In a prospective study, 51 patients undergoing radical head and neck irradiation at the Tokyo University Hospital were assessed for taste loss. Taste ability was measured by the taste threshold for the four basic tastes (sweet, sour, salt, and bitter qualities) plus another taste of "umami" quality using a filter-paper-disc method in patients before, during, and after radiotherapy (RT). RESULTS: All tastes declined on the fifth week after the start of RT and improved on the 11th week. Anatomic pathologic analyses in rats revealed that taste buds diminished completely on the sixth day after irradiation of 15 Gy in a single fraction, and the appearance of taste buds returned almost to the preirradiation state on the 28th day. CONCLUSIONS: The main cause of taste disorder resulting from RT was believed to be a disappearance of taste buds and not damage to the taste nerves.
Subject(s)
Head and Neck Neoplasms/radiotherapy , Taste Buds/radiation effects , Taste Disorders/etiology , Taste Threshold/radiation effects , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Prospective Studies , Radiation Dosage , Radiotherapy/adverse effects , Taste Disorders/diagnosis , Taste Disorders/physiopathologyABSTRACT
We have shown that the characteristics of tissue trees obtained by the hierarchical cluster analysis of DNA microarray data suggest the cellular expression patterns of genes in the gene clusters [J. Neurosci. Res. 74 (2003) 818]. We here identified three gene clusters containing 11 genes as a potential pool of candidate genes related to somatosensation in cranial structures such as the face, oral cavity and pharynx. To obtain the cellular expression profiles, eight genes other than three genes analyzed previously were subjected to in situ hybridization analysis. The results show that all of the 11 profiles are roughly similar and suggest that the positive cells are probably somatosensory neurons in two cranial sensory ganglia, the trigeminal and petrosal ganglia. The expression profiles and probable physiological functions of the 6 genes such as trkA, NaN and galanin suggest their direct involvement in specific somatosensory functions such as nociception. The function of another gene, calretinin, is putatively related to mechanosensation and proprioception. The roles of the remaining four genes, including aquaporin 1 and two EST clones, in sensory neurons are unknown, and may provide clues to understand the sensory function in TG and PG.
