‘The air that we breathe’: assessment of laser and electrosurgical dissection devices on operating theater air quality

Objectives

To measure changes in air quality during surgery.

Methods

Operating room (OR) and hallway air quality was continuously monitored over a 3-month period. Rooftop monitoring was used to control for environmental changes and to account for the infiltration of outdoor air pollutants. Air quality measurements were correlated with operative times and electro-dissection equipment used.

Results

OR air is cooler and drier compared to the adjacent hallway. Volatile organic compounds and other gases are below indoor air exposure limit guidelines. Lasers create greater 2.5 μm particulate matter (PM_2.5) mass concentration, and greater fine and coarse particle number than cautery or cold tissue dissection. Cautery produces more ultrafine particles (UFP) than other dissection techniques. OR air has lower particle counts than outdoor environmental air by virtue of air conditioning HEPA filtration.

Conclusion

Compared to the outside air, operating room air has lower particle counts. Lasers produce higher concentrations of PM_2.5 mass and, fine and coarse particle number counts. Cautery produces higher concentrations of UFP number counts than other modalities and warrants consideration of the use of masks with ultrafine particle filtration capacity. Operating room air is consistently cooler with decreased humidity, which may cause airway irritation.

Differential expression of transforming growth factor-beta in benign vs. papillary thyroid cancer nodules; a potential diagnostic tool?

Background

Thyroid nodules are common, but only 5% of nodules are found to be malignant. In North America, the incidence of thyroid cancer is increasing. Fine needle aspirate (FNA) biopsy is the diagnostic test of choice. Unfortunately, up to 20% of FNAs are non-diagnostic. A specific molecular marker for thyroid cancer is desirable. Evidence suggests that cell signaling through transforming growth factor beta (TGF- β) is important in the development of thyroid cancer. We sought to compare the expression of TGF- β in malignant and benign thyroid nodules.

Methods

From 2008-present, thyroid nodule tissue from thyroidectomy specimens was prospectively collected and stored at −80°C. RNA extraction and reverse transcription was performed on 47 samples (24 papillary thyroid cancer and 23 benign nodules). Quantitative PCR using SYBR green was performed to detect TGF-β-1 and −2. Resulting C_T values were normalized against β-actin. Gene expression was calculated using the 2^-ΔC_T method.

Results

A significantly greater expression of TGF- β1 (p < 0.0001) was detected in the group of malignant thyroid nodules compared to benign nodules. There was no difference in the expression of TGF- β2 (p = 0.4735) between the two groups.

Conclusions

In this study, we demonstrated that expression of TGF- β1 but not TGF- β2 is significantly increased in papillary thyroid cancer compared to benign thyroid nodules. This may serve as a potential diagnostic marker for papillary thyroid cancer.

Sex chromosome chimerism and the freemartin syndrome in Rideau Arcott sheep

In cattle, nearly all heifers born co-twin to a male are freemartins, XX/XY chimeras that exhibit a characteristic masculinized phenotype. However, in sheep, while litters containing males and females are common, freemartins are relatively rare. The primary aim of this study was to determine the frequency and features of XX/XY chimerism in female Rideau Arcott sheep. Also, breeding records were used to investigate the effect of litter size and sex ratios, as well as the genetic basis of the condition. Finally, the migration and transcriptional competence of cells of the opposite sex in the XX/XY female and male chimeras was explored. Genomic DNA (gDNA) from peripheral blood cells of ewes was screened by PCR for the male-specific SRY gene. Of 230 lambs screened, 10 were identified as chimeras. Litter size and sex ratio showed no statistically significant effect on the frequency of chimerism. PCR and FISH analysis confirmed the presence of opposite sex cells in female and male chimeras, and in the case of ewes, their migration to tissues other than blood. Transcriptional activity of SRY and AMH was detected in gonads of ewes, whereas XIST expression was detected in white blood cells of chimeric rams. It was concluded that the frequency of sex chromosome chimerism in Rideau Arcott sheep is estimated at 4.35%, with no significant effect of litter size and sex ratio. Moreover, as it was shown that opposite sex cells can migrate to tissues other than blood and be transcriptionally active in chimeric sheep, we speculate on the role they can play in these animals.