The identification and discrimination of viable cells is important to understand how experimental variables may influence biochemical processes such as cell metabolism, cell cycle, and signaling pathways. Cisplatin is commonly used as a viability stain in mass cytometry studies, however, recent work by Mei et al. has demonstrated that cisplatin can also be used to label antibodies, complicating the simultaneous use of the platinum measurement channels for both antibody and viability staining. This study demonstrates that other metal salts (hafnium chloride, niobium chloride, and zirconium chloride) can serve as substitutes for cisplatin in viability staining. These stains yield similar fractions of live and dead cells and stain the same dead cells in parallel high parameter analyses. In addition, this study demonstrates how a variety of protein antigen viability markers (pRb, Ki‐67, Histone H1, cleaved PARP, and GAPDH) can be used to discriminate live and dead cell populations, without the need for a separate viability staining step. As few as two of these protein antigen viability markers can help identify live and dead cell populations in fixed samples and can identify the same viable cells in high dimensional analyses with or without use of viability stain information. This study demonstrates several alternative approaches to mass cytometry viability assessment that can facilitate use of platinum isotopes for antibody staining and enables identification of live and dead cell populations in samples for which a separate viability stain is not practical.

BackgroundThe inverse log-linear relationship between Thyroid-stimulating hormone (TSH) and free thyroxine (FT4) is well established and reliably used for evaluation of hypothalamus-pituitary-thyroid (HPT) axis function.However, there are limited data regarding oncologic states in the TSH-FT4 relationship. The purpose of this study was to evaluate thyroid pituitary hypothalamic feedback regulation by the inverse log TSH and FT4 relationship in the cancer patient population at the Ohio State University Comprehensive Cancer Center (OSUCCC-James). MethodsThis retrospective study analyzed the correlation between TSH and FT4 results from 18846 outpatient subjects collected in August 2019-November 2021 at the Department of Family Medicine (OSU Wexner Medical Center), Department of Oncology (OSUCCC-James). Patients with diagnoses related to cancers were included in the oncology group. Patients with diagnoses not related to cancers were included in the non-oncology group. Patients of the

Background The inverse log-linear relationship between Thyroid-stimulating hormone (TSH) and free thyroxine (FT4) is well established and reliably used for evaluation of hypothalamus-pituitary-thyroid (HPT) axis function. However, there are limited data regarding oncologic states in the TSH-FT4 relationship. The purpose of this study was to evaluate thyroid pituitary hypothalamic feedback regulation by the inverse log TSH and FT4 relationship in the cancer patient population at the Ohio State University Comprehensive Cancer Center (OSUCCC-James). Methods This retrospective study analyzed the correlation between TSH and FT4 results from 18846 outpatient subjects collected in August 2019-November 2021 at the Department of Family Medicine (OSU Wexner Medical Center), Department of Oncology (OSUCCC-James). Patients with diagnoses related to cancers were included in the oncology group. Patients with diagnoses not related to cancers were included in the non-oncology group. Patients of the Department of Endocrinology, Department of Cardiology, Department of Obstetrics & Gynecology and Department of Hematology were excluded from this study. Time of collection for TSH and FT4 was from 7am to 7pm. Data were analyzed by morning (7am-12pm) and afternoon (12pm-7pm). Spearman correlation and non-linear fit were used for data analysis. Sex differences were analyzed as well in each group. Results Overall, an inverse correlation was observed between TSH and FT4 in both groups (non-oncology and oncology) regardless of sample collection time and sex differences. Further analysis by linear model in log TSH and FT4 showed a significant inverse fit in males compared with females in the oncology group of oncology, both in the afternoon (p < 0.05). Data were further analyzed by ranges of FT4, as lower or higher (pathophysiology) or within (physiology) the reference interval of FT4. There was no statistical significance between the non-oncology and oncology groups, but better correlation in non-oncology in either physiological or pathophysiological FT4 levels and sample collection time. Interestingly, the best correlation between TSH and FT4 was found in the non-oncology group at pathophysiological FT4 concentrations (abnormally high). In addition, at pathophysiological FT4 concentrations (abnormally low), the oncology group demonstrated a significant TSH response in the morning than in the afternoon (p < 0.05). Conclusions Though overall the TSH-FT4 curves showed an inverse relationship, there are variations of TSH-FT4 relationship for collection times when considering FT4 in physiological or pathophysiological states. The results advance understanding of TSH response, which is beneficial for the interpretation of thyroid disease. It is not recommended to evaluate thyroid pituitary hypothalamic axis by TSH results when FT4 is abnormally high in oncology patients or low in non-oncology patients, due to poor predictability and the potential for misdiagnosis. A better understanding of the complex nature of the TSH-FT4 relationship may need further study with better defining subclinical states of cancer patients.

Background The inverse log-linear relationship between TSH and free thyroxine (FT4) is well established and reliably used for evaluation of hypothalamus-pituitary-thyroid axis function. However, there are limited data regarding pathophysiologic states in the TSH-FT4 relationship. The purpose of this study was to evaluate thyroid pituitary hypothalamic feedback regulation by the inverse log TSH and FT4 relationship in cancer patient population at the Ohio State University Comprehensive Cancer Center (OSUCCC-James). Methods This retrospective study analyzed the correlation between TSH and FT4 results from 13039 outpatient subjects collected in August 2019-November 2021 at Department of Family Medicine (OSU Wexner Medical Center), Department of Oncology and Department of Chemotherapy (OSUCCC-James). Time of collection for TSH and FT4 was from 7am to 7pm. Data were analyzed by morning (7am-12pm) and afternoon (12pm-7pm). Spearman correlation and non-linear fit were used for data analysis. Sex differences were analyzed as well in each group. Results No significant differences of TSH or FT4 results were found across all study groups and times in both males and females. Overall, an inverse correlation was observed between TSH and FT4 in the morning and afternoon for both male and female populations in all the three groups. Further analysis by non-linear model in log TSH and FT4 showed a worse fit in the group of Oncology compared to the group of Family Medicine, specifically in the morning data set in both males and females. Interestingly, the inverse non-linear relationship between log TSH and FT4 in the female group designated Chemotherapy showed a better fit in the afternoon, compared with other data sets in the same group. Conclusions In cancer patients, the inverse non-linear relationship between TSH and FT4 is weak, which might be resultant of malignancy or medication treatments, or other unknown reasons. The results advance understanding of the pathophysiology and challenges of laboratory diagnosis of thyroid disease in cancer patients. A better understanding of the complex nature of the TSH-FT4 relationship may need further study with better defining subclinical states of cancer patients. Presentation: No date and time listed