BACKGROUNDS: The inferior pharyngeal constrictor muscle (IPC), which consists of the thyropharyngeus (TP) and cricopharyngeus (CP) muscles, plays an important role during deglutition, but their function is different when analysed by radiographic, manometric and electromyographic studies. OBJECTIVES AND MATERIALS: The purpose of this study is to quantify the expression levels of MHC mRNA isoforms (2B, 2X, 2A, 2L, beta-cardiac, neonatal and embryonic) in thyropharyngeus and cricopharyngeus muscles of rats using competitive PCR. RESULTS: The thyropharyngeus muscle was mainly consisted of three fast-twitching MHC isoforms, mostly 2X isoform (85.2%). On the other hand, the cricopharyngeus muscle contained two-third of fast-twitching isoforms(65.1%) and one-third of neonatal MHC(34.9%). CONCLUSIONS: The thyropharyngeus muscle could be characterized as a fast-twitching muscle and the cricopharyngeus muscle is probably considered as a sarcomeric regenerating muscle that is caused by frequently mechanical damage on deglutition.
Animals ; Deglutition ; Gene Expression ; Hand ; Muscles ; Myosin Heavy Chains* ; Myosins* ; Pharyngeal Muscles* ; Polymerase Chain Reaction ; Protein Isoforms ; Rats* ; RNA Isoforms ; RNA, Messenger*

The GSTP1 and NQO1 have been reported to be associated with an increased risk for smoking related head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to determine the effect of these metabolic gene polymorphisms on the risk of HNSCC. The study population included 294 histologically confirmed HNSCC cases and 333 controls without cancer. Genotyping analysis of the GSTP1 Ile105Val and NQO1 Trp139Arg genes was performed by polymerase chain reaction-based techniques on DNA prepared from peripheral blood. The Mantel-Haenszel chi-square test was used for statistical analysis. The allele frequencies of the GSTP1 and NQO1 polymorphisms were not statistically significant between cases and controls. In analyzing the association between smoking amounts and genetic polymorphisms, GSTP1 and NQO1 polymorphisms were associated with cigarette smoking amounts in cases. G allele containing genotypes in GSTP1 and T allele containing genotypes in NQO1 were associated with a tobacco dose-dependent increase in risk of HNSCC and these genotype distributions were statistically significant (p<0.05). We found that the GSTP1 105Val allele and NQO1 139Arg allele were associated with tobacco dose-dependent increase in risk of HNSCC. GSTP1 and NQO1 genotype polymorphisms may play an important role in the development of smoking related HNSCC.
Smoking/*epidemiology ; Risk Factors ; Risk Assessment/methods ; Prevalence ; Polymorphism, Single Nucleotide/genetics ; NAD(P)H Dehydrogenase (Quinone)/*genetics ; Middle Aged ; Male ; Korea/epidemiology ; Humans ; Head and Neck Neoplasms/*epidemiology/*genetics ; Glutathione S-Transferase pi/*genetics ; Genetic Predisposition to Disease/genetics ; DNA Mutational Analysis ; Carcinoma, Squamous Cell/*epidemiology/*genetics ; Aged, 80 and over ; Aged ; Adult