Background The major arterial supply to the thyroid gland is from the superior and inferior thyroid arteries, arising from the external carotid artery and the thyrocervical trunk respectively. The external laryngeal nerve runs in close proximity to the origin of the superior thyroid artery in relation to the thyroid gland. The superior thyroid artery is clinically important in head and neck surgeries. Objectives To locate the origin of the superior thyroid artery, because wide variability is reported. To provide knowledge of possible variations in its origin, because it is important for surgical procedures in the neck. Methods The origin of the superior thyroid artery was studied by dissecting sixty adult human hemineck specimens from donated cadavers in a Department of Anatomy. Results The highest incidence observed was origin of the superior thyroid artery from the external carotid artery (88.33%), whereas origin from the common carotid bifurcation only occurred in 8.33%. However, in 3.33% of cases, the superior thyroid artery originated from the common carotid artery and in a single case, the external laryngeal nerve did not cross the stem of the superior thyroid artery at all, but ran ventral and parallel to the artery. Conclusions It is important to rule out anomalous origin of superior thyroid artery and verify its relationship to the external laryngeal nerve prior to ligation of the artery in thyroid surgeries, in order to prevent iatrogenic injuries. Moreover, because anomalous origins of the superior thyroid artery are only anatomic variants, thorough knowledge of these is decisive for head and neck surgeries.
Background: Workers in cement warehouses of Kerala are enduring long-standing exposure to cement dust, which is considered genotoxic. Objective: To evaluate the extent of genotoxicity and cytotoxicity caused due to exposure of cement dust among those working in cement warehouses. Methods: The study included 82 cement warehouse workers and 82 age-matched individuals with no exposure to cement dust. Exfoliated buccal micronucleus cytome assay (BMCyt) was performed to analyze the genotoxic and cytotoxic effects caused by inhalation of cement dust. Results: The frequency of various genotoxic and cytotoxic end markers (micronucleated cells [2-fold increase, p<0.001], nuclear buds [4-fold increase, p<0.001], binucleated cells [4-fold increase, p<0.001], karyorrhectic cells [2-fold increase, p<0.001], pyknotic cells [3- fold increase, p<0.001], and karyolytic cells [2-fold increase, p<0.001]) were higher in the exposed workers compared with unexposed group. Increase of these parameters represented an increased level of chromosomal damage, nuclear disintegration and increased cell death among exposed group compared with unexposed group. Conclusion: Continuous exposure to cement dust results in increased frequency of nuclear aberrations and cellular apoptosis. This may lead to defects in genome maintenance, accelerated ageing, increased chance of oral cancer and neurodegenerative disorders in those occupationally exposed to cement dust.
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