Association of Insomnia and Obstructive Sleep Apnea with Worse Oral Mucositis and Quality of Life in Head and Neck Cancer Patients Undergoing Radiation Therapy

BACKGROUND

Patients with head and neck cancer (HNC) undergoing radiation therapy (RT) often experience sleep disturbances that may contribute to oral mucositis (OM) and quality of life (QOL).

METHODS

Patients with HNC treated with RT at a single institution were examined. Sleep questionnaires were given on the first day of RT to assess for insomnia and obstructive sleep apnea (OSA). Patient-reported QOL and oral mucositis were assessed during RT. Associations between insomnia and OSA with QOL were assessed using the Mann-Whitney U test. Linear mixed models assessed associations with OM.

RESULTS

Among 87 patients, 34 patients (39%) had subthreshold or greater insomnia and 47 patients (54%) screened positive for OSA. Upon RT completion, patients with subthreshold or greater insomnia had worse physical function (p = 0.005), fatigue (p = 0.01), insomnia (p < 0.001), and sticky saliva (p = 0.002). Patients screening positive for OSA had worse physical function (p = 0.01), sticky saliva (p = 0.02), fatigue (p = 0.007), insomnia (p = 0.009), and pain (p = 0.005). Upon linear mixed model evaluation, subthreshold or greater insomnia (p = 0.01) and positive OSA screen (p = 0.002) were associated with worse OM.

CONCLUSION

Insomnia and OSA are highly prevalent in patients with HNC undergoing RT. These sleep disturbances are associated with worse QOL and OM during treatment.

Advancing PROTAC Characterization: Structural Insights through Adducts and Multimodal Tandem-MS Strategies

Proteolysis targeting chimeras (PROTACs) are specialized molecules that bind to a target protein and a ubiquitin ligase to facilitate protein degradation. Despite their significance, native PROTACs have not undergone tandem mass spectrometry (MS) analysis. To address this gap, we conducted a pioneering investigation on the fragmentation patterns of two PROTACs in development, dBET1 and VZ185. Employing diverse cations (sodium, lithium, and silver) and multiple tandem-MS techniques, we enhanced their structural characterization. Notably, lithium cations facilitated comprehensive positive-mode coverage for dBET1, while negative polarity mode offered richer insights. Employing de novo structure determination on 2DMS data from degradation studies yielded crucial insights. In the case of VZ185, various charge states were observed, with [M + 2H]2+ revealing fewer moieties than [M + H]+ due to charge-related factors. Augmenting structural details through silver adducts suggested both charge-directed and charge-remote fragmentation. This comprehensive investigation identifies frequently dissociated bonds across multiple fragmentation techniques, pinpointing optimal approaches for elucidating PROTAC structures. The findings contribute to advancing our understanding of PROTACs, pivotal for their continued development as promising therapeutic agents.

Review of fragmentation of synthetic single-stranded oligonucleotides by tandem mass spectrometry from 2014 to 2022

The fragmentation of oligonucleotides by mass spectrometry allows for the determination of their sequences. It is necessary to understand how oligonucleotides dissociate in the gas phase, which allows interpretation of data to obtain sequence information. Since 2014, a range of fragmentation mechanisms, including a novel internal rearrangement, have been proposed using different ion dissociation techniques. The recent publications have focused on the fragmentation of modified oligonucleotides such as locked nucleic acids, modified nucleobases (methylated, spacer, nebularine and aminopurine) and modification to the carbon 2'-position on the sugar ring; these modified oligonucleotides are of great interest as therapeutics. Comparisons of different dissociation techniques have been reported, including novel approaches such as plasma electron detachment dissociation and radical transfer dissociation. This review covers the period 2014-2022 and details the new knowledge gained with respect to oligonucleotide dissociation using tandem mass spectrometry (without priori sample digestion) during that time, with a specific focus on synthetic single-stranded oligonucleotides.

Skeletal muscle index is associated with long term outcomes after lobectomy for non-small cell lung cancer

BACKGROUND

Skeletal muscle indices have been associated with improved peri-operative outcomes after surgical resection of non-small-cell lung cancer (NSCLC). However, it is unclear if these indices can predict long term cancer specific outcomes.

METHODS

NSCLC patients undergoing lobectomy at our institute between 2009-2015 were included in this analysis (N = 492). Preoperative CT scans were used to quantify skeletal muscle index (SMI) at L4 using sliceOmatic software. Cox proportional modelling was performed for overall (OS) and recurrence free survival (RFS).

RESULTS

For all patients, median SMI was 45.7 cm2/m2 (IQR, 40-53.8). SMI was negatively associated with age (R = -0.2; p < 0.05) and positively associated with BMI (R = 0.46; P < 0.05). No association with either OS or RFS was seen with univariate cox modelling. However, multivariable modelling for SMI with patient age, gender, race, smoking status, DLCO and FEV1 (% predicted), American Society of Anesthesiology (ASA) score, tumor histology and stage, and postoperative neoadjuvant therapy showed improved OS (HR = 0.97; P = 0.0005) and RFS (HR = 0.97; P = 0.01) with SMI. Using sex specific median SMI as cutoff, a lower SMI was associated with poor OS (HR = 1.65, P = 0.001) and RFS (HR = 1.47, P = 0.03).

CONCLUSIONS

SMI is associated with improved outcomes after resection of NSCLC. Further studies are needed to understand the biological basis of this observation. This study provides additional rationale for designing and implementation of rehabilitation trials after surgical resection, to gain durable oncologic benefit.

Association of pre-treatment lymphocyte-monocyte ratio with survival outcome in patients with head and neck cancer treated with chemoradiation

BACKGROUND

Given the role of systematic inflammation in cancer progression, lymphocyte-monocyte ratio (LMR) from peripheral blood has been suggested as a biomarker to assess the extent of inflammation in several solid malignancies. However, the role of LMR as a prognostic factor in head and neck cancer was unclear in several meta-analyses, and there is a paucity of literature including patients in North America. We performed an observational cohort study to evaluate the association of LMR with survival outcomes in North American patients with head and neck cancer.

METHODS

A single-institution, retrospective database was queried for patients with non-metastatic head and neck cancer who underwent definitive chemoradiation from June 2007 to April 2021 at the Roswell Park Comprehensive Cancer Center. Primary endpoints were overall survival (OS) and cancer-specific survival (CSS). The association of LMR with OS and CSS was examined using nonlinear Cox proportional hazard model using restricted cubic splines (RCS). Cox multivariable analysis (MVA) and Kaplan-Meier method were used to analyze OS and CSS. Pre-radiation LMR was then stratified into high and low based on its median value. Propensity scored matching was used to reduce the selection bias.

RESULTS

A total of 476 patients met our criteria. Median follow up was 45.3 months (interquartile range 22.8-74.0). The nonlinear Cox regression model showed that low LMR was associated with worse OS and CSS in a continuous fashion without plateau for both OS and CSS. On Cox MVA, higher LMR as a continuous variable was associated with improved OS (adjusted hazard ratio [aHR] 0,90, 95% confidence interval [CI] 0.82-0.99, p = 0.03) and CSS (aHR 0.83, 95% CI 0.72-0.95, p = 0.009). The median value of LMR was 3.8. After propensity score matching, a total of 186 pairs were matched. Lower LMR than 3.8 remained to be associated with worse OS (HR 1.59, 95% CI 1.12-2.26, p = 0.009) and CSS (HR 1.68, 95% CI 1.08-2.63, p = 0.02).

CONCLUSION

Low LMR, both as a continuous variable and dichotomized variable, was associated with worse OS and CSS. Further studies would be warranted to evaluate the role of such prognostic marker to tailor interventions.

Association of Body Mass Index With Outcomes Among Patients With Head and Neck Cancer Treated With Chemoradiotherapy

Importance

Combined modality therapy, such as chemoradiotherapy, often results in significant morbidity among patients with head and neck cancer. Although the role of body mass index (BMI) varies based on cancer subtypes, its association with treatment response, tumor recurrence, and survival outcomes among patients with head and neck cancer remains unclear.

Objective

To evaluate the role of BMI in treatment response, tumor recurrence, and survival outcomes among patients with head and neck cancer undergoing chemoradiotherapy.

Design, Setting, and Participants

This retrospective, observational, single-institution cohort study conducted at a comprehensive cancer center included 445 patients with nonmetastatic head and neck cancer who underwent chemoradiotherapy from January 1, 2005, to January 31, 2021.

Exposure

Normal vs overweight or obese BMI.

Main Outcomes and Measures

Metabolic response after chemoradiotherapy, locoregional failure (LRF), distant failure (DF), overall survival (OS), and progression-free survival (PFS), with Bonferroni correction used to adjust for multiple comparisons and P < .025 being considered statistically significant.

Results

A total of 445 patients (373 men [83.8%]; median age, 61 years [IQR, 55-66 years]; 107 [24.0%] with normal BMI, 179 [40.2%] with overweight BMI, and 159 [35.7%] with obese BMI) were included for analysis. Median follow-up was 48.1 months (IQR, 24.7-74.9 months). On Cox proportional hazards regression multivariable analysis, only overweight BMI was associated with improved OS (5-year OS, 71.5% vs 58.4%; adjusted hazard ratio [AHR], 0.59 [95% CI, 0.39-0.91]; P = .02) and PFS (5-year PFS, 68.3% vs 50.8%; AHR, 0.51 [95% CI, 0.34-0.75]; P < .001). On logistic multivariable analysis, overweight BMI (91.6% vs 73.8%; adjusted odds ratio [AOR], 0.86 [95% CI, 0.80-0.93]; P < .001) and obese BMI (90.6% vs 73.8%; AOR, 0.89 [95% CI, 0.81-0.96]; P = .005) were associated with complete metabolic response on follow-up positron emission tomography-computed tomography after treatments. On Fine-Gray multivariable analysis, overweight BMI was associated with reduction in LRF (5-year LRF, 7.0% vs 25.9%; AHR, 0.30 [95% CI, 0.12-0.71]; P = .01), but not DF (5-year DF, 17.4% vs 21.5%; AHR, 0.92 [95% CI, 0.47-1.77]; P = .79). Obese BMI was not associated with LRF (5-year LRF, 10.4% vs 25.9%; AHR, 0.63 [95% CI, 0.29-1.37]; P = .24) or DF (5-year DF, 15.0% vs 21.5%; AHR, 0.70 [95% CI, 0.35-1.38]; P = .30).

Conclusion

In this cohort study of patients with head and neck cancer, when compared with normal BMI, overweight BMI was an independent factor favorably associated with complete response after treatments, OS, PFS, and LRF. Further investigations are warranted to improve understanding on the role of BMI among patients with head and neck cancer.

Defining the optimal threshold and prognostic utility of pre-treatment hemoglobin level as a biomarker for survival outcomes in head and neck cancer patients receiving chemoradiation

OBJECTIVES

We sought to define the optimal threshold for anemia in North American head and neck cancer patients and evaluate its role as a prognostic biomarker.

MATERIALS AND METHODS

A single-institution database was queried for patients with head and neck cancer who underwent chemoradiation from January 2005 to April 2021. An optimal threshold of hemoglobin (Hgb) level was defined based on maximum log-rank test statistic. Cox multivariable analysis (MVA), Kaplan-Meier, and propensity score matching were performed to evaluate treatment outcomes.

RESULTS

A total of 496 patients were identified. Threshold for Hgb was determined to be 11.4 for both overall survival (OS) and progression-free survival (PFS). Low Hgb was associated with worse OS (adjusted hazards ratio [aHR] 2.41, 95 % confidence interval [CI] 1.53-3.80, p < 0.001) and PFS (aHR 2.01, 95 % CI 1.30-3.11, p = 0.002). Similar findings were observed among 39 matched pairs for OS (5-year OS 22.3 % vs 49.0 %; HR 2.22, 95 % CI 1.23-4.03, p = 0.008) and PFS (5-year PFS 24.3 % vs 39.1 %; HR 1.78, 95 % CI 1.02-3.12, p = 0.04). Among those with HPV-negative tumors, low Hgb was associated with worse OS (aHR 13.90, 95 % CI 4.66-41.44, p < 0.001) and PFS (aHR 5.24, 95 % CI 2.09-13.18, p < 0.001). However, among those with HPV-positive tumors, low Hgb was not associated with both OS (aHR 1.75, 95 % CI 0.60-5.09, p = 0.31) and PFS (aHR 1.13, 95 % CI 0.41-3.14, p = 0.82).

CONCLUSION AND RELEVANCE

Low Hgb below 11.4 was an independent adverse prognostic factor for worse survival. It was also prognostic among patients with HPV-negative tumors, but not for HPV-positive tumors.

Effect of musculature on mortality, a retrospective cohort study

BACKGROUND

While often life-saving, treatment for head and neck cancer (HNC) can be debilitating resulting in unplanned hospitalization. Hospitalizations in cancer patients may disrupt treatment and result in poor outcomes. Pre-treatment muscle quality and quantity ascertained through diagnostic imaging may help identify patients at high risk of poor outcomes early. The primary objective of this study was to determine if pre-treatment musculature was associated with all-cause mortality.

METHODS

Patient demographic and clinical characteristics were abstracted from the cancer center electronic database (n = 403). Musculature was ascertained from pre-treatment CT scans. Propensity score matching was utilized to adjust for confounding bias when comparing patients with and without myosteatosis and with and without low muscle mass (LMM). Overall survival (OS) was evaluated using the Kaplan-Meier method and Cox multivariable analysis.

RESULTS

A majority of patients were male (81.6%), white (89.6%), with stage IV (41.2%) oropharyngeal cancer (51.1%) treated with definitive radiation and chemotherapy (93.3%). Patients with myosteatosis and those with LMM were more likely to die compared to those with normal musculature (5-yr OS HR 1.55; 95% CI 1.03-2.34; HR 1.58; 95% CI 1.04-2.38).

CONCLUSIONS

Musculature at the time of diagnosis was associated with overall mortality. Diagnostic imaging could be utilized to aid in assessing candidates for interventions targeted at maintaining and increasing muscle reserves.

Evaluation of Optimal Threshold of Neutrophil-Lymphocyte Ratio and Its Association With Survival Outcomes Among Patients With Head and Neck Cancer

IMPORTANCE

Given the role of inflammation in cancer progression, neutrophil-lymphocyte ratio (NLR) from peripheral blood has been suggested as a readout of systemic inflammation and a prognostic marker in several solid malignant neoplasms. However, optimal threshold for NLR in US patients with head and neck cancer remains unclear.

OBJECTIVE

To evaluate the optimal NLR threshold as a potential prognostic biomarker for survival outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was conducted at a single institution. Participants included 496 patients with nonmetastatic head and neck cancer who underwent chemoradiation from April 2007 to March 2021. Statistical analysis was performed from September to December 2021.

EXPOSURES

High vs low NLR.

MAIN OUTCOMES AND MEASURES

Overall survival (OS) and cancer-specific survival (CSS).

RESULTS

A total of 496 patients (411 male patients [82.9%]; 432 White patients [87.1%]; 64 patients with other race or ethnicity [12.9%]; median [IQR] age, 61 [55-67] years) were identified. Median (IQR) follow-up was 44.4 (22.8-74.0) months. Thresholds of NLR for both OS and CSS were 5.71. High NLR above 5.71 was associated with worse OS (adjusted hazard ratio [aHR], 1.97; 95% CI, 1.26-3.09; P = .003) and CSS (aHR, 2.33; 95% CI, 1.38-3.95; P = .002). On logistic multivariable analysis, patients were more likely to have high NLR if they had higher T and N staging (T3-4: aOR, 4.07; 95% CI, 1.92-9.16; P < .001; N2: aOR, 2.97; 95% CI, 1.04-9.17; P = .049; N3: aOR, 11.21; 95% CI, 2.84-46.97; P < .001), but less likely if they had a good performance status (Karnofsky Performance Status 90-100: aOR, 0.29; 95% CI, 0.14-0.59; P < .001). Among 331 patients (66.7%) with available human papillomavirus (HPV) data, high NLR was not associated with OS (HPV-negative: aHR, 2.46; 95% CI, 0.96-6.31; P = .06; HPV-positive: aHR, 1.17; 95% CI, 0.38-3.56; P = .78) and CSS (HPV-negative: aHR, 2.55; 95% CI, 0.81-7.99; P = .11; HPV-positive: aHR, 1.45; 95% CI, 0.44-4.76; P = .54).

CONCLUSIONS AND RELEVANCE

High NLR was associated with worse survival. Patients with substantial disease burden and poor performance status were more likely to have high NLR. These findings suggest that further studies would be warranted to investigate the role of such prognostic marker to identify patients at risk to tailor interventions.

Three-Day Dietary Manipulation in Multiple Sclerosis: Exercise and Fatigue Outcomes

Background

In persons with multiple sclerosis (MS), the effect of nutrition on exercise performance and fatigue remains unknown. The objective was to determine whether a 3-day diet high in triglycerides (FAT) compared with a 3-day diet high in carbohydrates (CARB) would improve fatigue and exercise performance in persons with MS.

Methods

A randomized controlled crossover design was incorporated to study FAT versus CARB on submaximal cycling endurance (60% of peak oxygen consumption), substrate utilization, and fatigue in 12 persons with mild-to-moderate MS (Expanded Disability Status Scale score, 2.0-5.0) and 12 age- and sex-matched controls.

Results

There were no differences in cycling time between diets in either group (P = .29). The MS group had no changes in fatigue between diets (P = .64); the control group demonstrated increased total mental fatigue after FAT (P = .05). The control group increased carbohydrate oxidation by 24% at rest and 13% during exercise after CARB. Similarly, the control group significantly increased fat oxidation after FAT by 22% at rest and 68% during exercise (P = .01). These changes were not seen in the MS group. Compared with controls, persons with MS oxidized approximately 50% less fat during exercise after FAT (P = .05).

Conclusions

Neither CARB nor FAT altered submaximal exercise performance or baseline fatigue in the MS group. The results suggest that persons with MS are unable to adapt to dietary changes and oxidize fatty acids as efficiently as controls.

A Retrospective Cohort Study of Myosteatosis and Quality of Life in Head and Neck Cancer Patients

Simple Summary

Quality of life (QOL) is an important patient reported outcome that effects both care and life outside of treatment. There is a shortage of nontaxing ways to determine which patients may need enhanced care over the course of their therapy and beyond to help avoid long-term declines in QOL. Therefore, we investigated whether myosteatosis as determined through existing diagnostic imaging could be used to predict QOL trajectories. In this study, patients with pretreatment myosteatosis were more likely to have lower physical and global QOL scores than patients with normal muscle density. In conclusion, myosteatosis may be a way of determining patients in need of extra assistance over the course of treatment and afterwards.

Abstract

Head and neck cancer (HNC) treatment-related morbidity can be detrimental to quality of life (QOL). Myosteatosis is associated with poor QOL in multiple cancers. If predictive of poor QOL trajectories, myosteatosis would be a tool for clinicians to determine which patients may require additional support during treatment. The purpose of this study was to determine if pretreatment myosteatosis is associated with a poor QOL trajectory following treatment completion. Methods: In a retrospective cohort design, myosteatosis was determined from pretreatment CT scans. Both physical and global QOL score was assessed through patient interview on follow-up appointment. Demographic, cancer-specific, and social covariates were collected, reported, and considered as potential confounders. Results: The population of 163 patients was mostly male (82.2%) and white (91.4%) with oropharyngeal cancer (55.8%). Males with myosteatosis had a physical QOL score 46.84 points lower at one-year following treatment completion (p = 0.01) than those with normal muscle density (p = 0.01). Males with myosteatosis averaged 57.57 points lower at one-year post-treatment (p = 0.01) in global QOL scores. Conclusions: Over one year following completion of treatment, patients with myosteatosis reported worse physical and global QOL scores than patients with normal muscle density.

Financial Counseling Is Associated with Reduced Financial Difficulty Scores in Head and Neck Cancer Patients Treated with Radiation Therapy

BACKGROUND

Financial toxicity (FT) can be devastating to cancer patients, and solutions are urgently needed. We investigated the impact of financial counseling (FC) on FT in head and neck cancer (HNC) patients.

METHODS

Via a single-institution database, we reviewed the charts of HNC patients who underwent definitive or post-operative radiotherapy, from October 2013 to December 2020. Of these patients, 387 had provided baseline and post-treatment information regarding financial difficulty. In July 2018, a dedicated financial counselor was provided for radiation therapy patients and we subsequently examined the impact of FC on financial difficulty scores.

RESULTS

Following the hiring of a dedicated financial counselor, there was a significant increase in the proportion of patients receiving FC (5.3% vs. 62.7%, p < 0.0001). Compared with baseline scores, patients who did not undergo FC had a significant increase in reported financial difficulty at the end of treatment (p = 0.002). On the other hand, there was no difference in pre- and post-treatment scores in patients who had received FC (p = 0.588). After adjusting for gender and nodal status with a multiple linear regression model, FC was significantly associated with change in financial difficulty (β = -0.204 ± 0.096, p = 0.035). On average, patients who received FC had a 0.2 units lower change in financial difficulty score as compared with those with the same gender and nodal stage but without FC.

CONCLUSIONS

Providing a dedicated financial counselor significantly increased the proportion of HNC receiving FC, resulting in the stabilization of financial difficulty scores post-treatment. Based on a multiple linear regression model, FC was independently associated with reduced financial difficulty. The employment of a financial counselor may be a viable, hospital-based approach to begin to address FT in HNC.

Matched pair analysis for comparison of survival outcome of alternative regimens to standard three-weekly cisplatin-based concurrent chemoradiation of head and neck cancer

Background

To compare head and neck cancer (HNC) patients treated with three-weekly versus weekly cisplatin-based or other chemotherapy-based concurrent chemoradiation (CRT) and CRT with versus without induction chemotherapy (ICT) to investigate differences in overall survival (OS) and cancer-specific survival (CSS).

Methods

HNC patients treated with definitive or adjuvant CRT at Roswell Park Comprehensive Cancer Center between 2003 and 2017 were retrospectively reviewed. Propensity score matching was performed to obtain three sets of balanced matched pairs: three-weekly and weekly cisplatin CRT, three weekly and non-cisplatin CRT, CRT with and without ICT. Multivariate Cox regression and Kaplan-Meier analyses were used to estimate and compare survival outcomes.

Results

A total of 623 patients received either definitive (81%) or post-operative (19%) RT. Of these, 283 patients concurrently received three-weekly cisplatin (45%); 189 patients (30%) received weekly cisplatin; 151 patients (24%) received non-cisplatin regimen. Median follow-up was 55.4 months (interquartile range, 38.0–88.7). Patients who received CRT alone and those who received ICT and CRT had no difference in 5-year OS (51.5% and 41.0% respectively, P=0.53) and CSS (64.9% and 49.7% respectively, P=0.21). Compared to patients who received three-weekly cisplatin, patients who received weekly cisplatin had no difference in 5-year OS (59.3% vs. 54.1%, P=0.35) and CSS (70.3% vs. 62.4%, P=0.09); patients who received non-cisplatin CRT also had no difference in 5-year OS (54.5% vs. 58.3%, P=0.51) and CSS (67.5% vs. 64.7%, P=0.45).

Conclusions

No significant difference in OS and CSS was observed in any of the three pairs of CRT regimens. ICT prior to CRT did not improve survival of CRT alone. Non-cisplatin and weekly cisplatin regimens did not prove to be inferior to the standard three-weekly cisplatin.

Matched pair analysis to evaluate weight loss during radiation therapy for head and neck cancer as a prognostic factor for survival

Background

One frequent consequence of radiation therapy (RT) for head and neck cancer (HNC) is weight loss (WL). HNC patients reportedly lose about 9% of their weight during treatment, regardless of pre-treatment WL and nutritional support. We investigated whether high WL during RT has an association with overall (OS) and cancer-specific survival (CSS).

Methods

We retrospectively reviewed weight during RT in HNC patients treated at Roswell Park Comprehensive Cancer Center between 2003 and 2017. High WL was defined as greater than or equal to the median WL. Logistic regression analysis was performed to identify predictors for WL during RT. Multivariate Cox regression and Kaplan-Meier analyses were used to estimate survival outcomes. Propensity score matching was performed to obtain balanced matched-pairs and compare survival outcomes.

Results

A total of 843 patients received either definitive (71%) or post-operative (29%) RT. Median follow-up was 53.6 months [interquartile range (IQR) 35.7–88.9]. Median WL was 5.8% (IQR 0.24–10.6) from baseline weight. Patients with high WL had better OS [hazard ratio (HR) 0.75, 95% confidence interval (CI), 0.61–0.93, P=0.01] and CSS (HR 0.71, 95% CI, 0.55–0.93, P=0.01). 258 matched-pairs were analyzed. Median follow-up was 54.8 months (IQR 35.8–90.4). Median OS was 39.2 months (IQR 21.4–75.7) for high WL versus 36.7 months (IQR 14.6–61.7) for low WL cohorts (P=0.047).

Conclusions

Different from previous reports, this study shows that patients with less WL have worse OS. WL during RT may not be a reliable marker for worse prognosis. A better way to evaluate malnutrition in patients undergoing RT is warranted.

Application of open port sampling interface mass spectrometry (OPSI-MS) to deuterium exchange as an aid for structural elucidation

RATIONALE

Deuterium exchange has been demonstrated to provide additional information to accurate mass measurement and collision-induced dissociation on unknown chemical structures. An enhanced method for rapid deuterium exchange could make this technique more routine for structural elucidation. Open port sampling interface mass spectrometry (OPSI-MS) with an aprotic solvent offers a rapid method for performing deuterium incorporation.

METHODS

Samples of standard drug molecules have been analysed by OPSI-MS directly from solids using a make-up flow of acetonitrile + 0.1% trifluoroacetic acid. The resultant spectra were compared with those obtained by OPSI-MS analysis of the samples dissolved in deuterium oxide (D₂ O). Solutions of these molecules in acetonitrile/D₂ O were analysed using an Atmospheric Solids Analysis Probe (ASAP) at different temperatures to compare the suitability of this technique.

RESULTS

The number of exchangeable hydrogens was obtained through deuterium exchange using the OPSI source, although there was some incomplete exchange or back-exchange observed. Molecules with one to five exchangeable hydrogens were successfully analysed. ASAP analysis produced more complicated spectra with higher levels of incomplete or back-exchanged ions; this was more pronounced at higher temperatures.

CONCLUSIONS

The use of OPSI provides a method for the rapid determination of the number of exchangeable hydrogens within a molecule. This yields useful information as an aid to the structural elucidation of unknowns. ASAP produces incomplete exchange and cannot be used for incorporation studies.

Change in Physical Performance Correlates with Decline in Quality of Life and Frailty Status in Head and Neck Cancer Patients Undergoing Radiation with and without Chemotherapy

Simple Summary

Quality of life (QoL) scores and frailty status are becoming increasingly important criterion with implications on both how patients are treated and survival in head and neck cancer (HNC). Despite this, physicians lack tools to identify patients who are at risk of suffering declines in QoL and becoming frail following treatment. Therefore, we investigated whether functional decline, as measured by a series of physical tests called the Short Physical Performance Battery (SPPB), correlated with a reduction in QoL and increased risk of frailty. In the current study, patients who experienced a decline in SPPB scores were significantly more likely to have changes in physical functioning QoL measures as well as transition to frail status following treatment. In conclusion, the SPPB may be a useful tool to identify patients who may benefit from additional rehabilitation in future studies.

Abstract

Patient-reported quality of life (QoL) metrics, frailty status, and physical functioning are emerging concepts in head and neck cancer (HNC) with implications on both treatment decision-making and prognosis. The impact of treatment-related functional decline on QoL and frailty has not been well-characterized in HNC and was the focus of this investigation. Methods: Patients who underwent radiation therapy for HNC from 2018 to 2020 were evaluated as a prospective observational cohort. Functional decline, QoL, and the frailty phenotype were measured via the Short Physical Performance Battery (SPPB), European Organization for Research and Treatment of Cancer (EORTC) qlq-C30, and Fried Frailty index, respectively. Results: A total of 106 HNC patients were included, 75 of which received concurrent chemoradiation therapy (CCRT) and 31 received radiation alone, both with and without surgery. There was a decrease in SPPB overall (p < 0.001) from the beginning to the end of treatment in the CCRT group but not the radiation group (p = 0.43). Change in overall SPPB points following treatment correlated with the decline in physical QoL for both groups (p < 0.05) as well as transition frail status in the CCRT group (p < 0.001) with a trend in the radiation group (p = 0.08). Conclusions: Change in SPPB correlates with QoL and transition to frailty status in patients undergoing definitive CCRT for HNC with similar trends in those receiving radiation alone. Decline in SPPB could potentially be useful in identification of those who may benefit from rehabilitation in future studies.

Association of significant financial burden with survival for head and neck cancer patients treated with radiation therapy

OBJECTIVE

To assess the association between financial toxicity and survival in patients with head and neck cancer (HNC).

MATERIALS AND METHODS

Using a single-institution database, we retrospectively reviewed HNC patients treated at Roswell Park Comprehensive Cancer Center treated with definitive or postoperative radiation therapy between 2013 and 2017. Kaplan-Meier method and log-rank tests were used to analyze survival outcomes. Propensity score matching on all clinically relevant baseline characteristics was performed to address selection bias. All statistical tests were two-sided and those less than 0.05 were considered statistically significant.

RESULTS

Of a total of 284 HNC patients (age: median 61 years, IQR 55-67; 220 [77.5%] men), 204 patients (71.8%) received definitive radiation and 80 patients (28.2%) received adjuvant radiation. There were 41 patients (14.4%) who reported high baseline financial toxicity. Chemotherapy was used in 237 patients (83.5%). On multivariable analysis, those with high financial toxicity exhibited worse overall survival (hazards ratio [HR] 1.75, 95% confidence interval [CI] 1.05-2.94, p = 0.03) and cancer specific survival (HR 2.28, 95% CI 1.31-3.96, p = 0.003). On matched pair analysis of 66 patients, high financial toxicity remained associated with worse OS (HR 2.72, 95% CI 1.04-7.09, p = 0.04) and CSS (HR 3.75, 95% CI 1.22-11.5, p = 0.02).

CONCLUSION

HNC patient reported baseline financial toxicity was significantly correlated with both decreased overall and cancer specific survival. These significant correlations held after match pairing. Further research is warranted to investigate the impact of financial toxicity in HNC and mitigate its risk.

Towards a generic method for ion chromatography/mass spectrometry of low-molecular-weight amines in pharmaceutical drug discovery and development

RATIONALE

Low-molecular-weight amines are encountered in pharmaceutical analysis, e.g. as reactants in chemical syntheses, but are challenging to analyse using ultrahigh-performance liquid chromatography/mass spectrometry (UHPLC/MS) due to their high polarity causing poor retention. Ion chromatography/mass spectrometry (IC/MS) is an emerging technique for polar molecule analysis that offers better separation. A generic IC/MS method would overcome problems associated with using UHPLC/MS in drug discovery and development environments.

METHODS

Amine standards were analysed using IC/MS with gradient elution (variety of column temperatures evaluated). An electrospray ionisation (ESI) quadrupole mass spectrometer was operated in positive ion polarity in scanning mode. The make-up flow composition was evaluated by assessing the performance of a range of organic modifiers (acetonitrile, ethanol, methanol) and additives (acetic acid, formic acid, methanesulfonic acid). The ESI conditions were optimised to minimise adduct formation and promote generation of protonated molecules.

RESULTS

The performance attributes were investigated and optimised for low-molecular-weight amine analysis. Organic solvents and acidic additives were evaluated as make-up flow components to promote ESI, with 0.05% acetic acid in ethanol optimal for producing protonated molecules. The hydrogen bonding capability of amines led to abundant protonated molecule-solvent complexes; optimisation of source conditions reduced these, with collision-induced dissociation voltage having a strong effect. The detection limit was ≤1.78 ng for the amines analysed, which is fit-for-purpose for an open-access chemistry environment.

CONCLUSIONS

This study demonstrates the value of IC/MS for analysing low-molecular-weight amines. Good chromatographic separation of mixtures was possible without derivatisation. Ionisation efficiency was greatest using a make-up flow of 0.05% acetic acid in ethanol, and optimisation of ESI source conditions promoted protonated molecule generation for easy determination of molecular weight.

Matched pair analysis to evaluate the impact of hospitalization during radiation therapy as an early marker of survival in head and neck cancer patients

BACKGROUND

Complications from radiotherapy (RT) alone or combined with surgery and/or chemotherapy for head and neck cancer (HNC) sometimes necessitate hospitalization. Our aim was to evaluate the frequency, cause, and survival outcomes associated with hospitalizations in patients undergoing RT for HNC.

PATIENTS AND METHODS

Using a retrospective single-institution database, we reviewed hospitalization records of HNC patients treated at Roswell Park Comprehensive Cancer Center with definitive or post-operative RT between 2003 and 2017. Patients who were admitted during treatment and within 90-days post-RT were identified. Multivariate analyses, Kaplan-Meier statistics, and analysis on propensity score matching were performed to obtain matched-pair, after matching baseline characteristics, such as age, gender, smoking, tumor staging, p16 status, and treatments received.

RESULTS

839 patients were eligible for analysis. Median follow-up was 34.8 months (Interquartile range [IQR] 15.6-64.8). 595 (71%) received definitive RT and 244 (29%) received adjuvant RT. Chemotherapy was used in 671 patients (80%). 171 patients (20%) had at least one hospitalization. Dehydration (40%) and fever (29%) were the most frequent causes of admission. Hospitalized patients had significantly worse overall survival (OS) (Hazards ratio [HR] 1.61, 95% CI 1.26-2.07, p < 0.001) and cancer-specific survival (CSS) (HR 1.45, 95% CI 1.07-1.95, p = 0.02). 163 matched pairs had median follow-up of 58.6 months (IQR 37.6-85.0). Median OS was 34.5 months (IQR 13.3-58.0) for hospitalized versus 44.2 months (IQR 20.3-78.7) for non-hospitalized patients (p = 0.01).

CONCLUSION

This study reveals significantly worse OS and CSS for patients hospitalized during RT for HNC. Hospitalization may be an early marker for worse survival.

Impurity analysis of 2-butynoic acid by ion chromatography-mass spectrometry

Small organic acids are widely used within the pharmaceutical industry but can be difficult to analyse. Ion chromatography is a suitable technique for the analysis of these acids but method development can be hindered as mass spectrometry is not often used as a detector; this means that peak tracking and peak purity cannot be performed. The authors report method development for the analysis of 2-butynoic acid, where by using electrospray ionisation mass spectrometry, peak purity was investigated and the presence of co-eluting impurities determined. Optimisation of the additives in the make-up flow to the mass spectrometer was shown to have an impact on the response observed. A standard series of organic acids were analysed spiked in to 2-butynoic acid at levels representative of impurities, the presence of the 2-butynoic acid did not impact the linearity or limit of detection observed for the acids; R² values greater than 0.98 were obtained for all acids with and without the presence of 2-butynoic acid with a limit of detection at 1 ppb for all but one of the acids.

Impact of Nutritional Intake on Function in People with Mild-to-Moderate Multiple Sclerosis

Background

We sought to assess the associations between nutrition and ambulation, daily activity, quality of life (QOL), and fatigue in individuals with mild-to-moderate disability with multiple sclerosis (MS).

Methods

This cross-sectional pilot study included 20 ambulatory adult volunteers with MS (14 women and 6 men; mean ± SD age, 57.9 ± 10.2 years; mean ± SD Expanded Disability Status Scale score = 4.1 ± 1.8). Primary outcome variables included dietary assessment and the 6-Minute Walk Test (6MWT). Secondary measures included the Timed 25-Foot Walk test, Timed Up and Go test, daily activity, and three self-report questionnaires: the 12-item Multiple Sclerosis Walking Scale, the 36-item Short Form Health Survey (SF-36), and the Modified Fatigue Impact Scale.

Results

Significant correlations were seen between the percentage of diet comprising fats and the 6MWT (r = 0.51, P = .02) and the physical functioning component of the SF-36 (r = 0.47, P = .03). The percentage of carbohydrates was significantly correlated with the 6MWT (r = -0.43, P = .05), daily activity (r = -0.59, P = .005), and the physical functioning component of the SF-36 (r = -0.47, P = .03). Cholesterol, folate, iron, and magnesium were significantly positively correlated with the physical functioning component of the SF-36 and the 6MWT.

Conclusions

These findings indicate better ambulation, daily function, and QOL with increased fat intake, decreased carbohydrate intake, and increased intake of the micronutrients cholesterol, folate, iron, and magnesium in people with mild-to-moderate MS. This pilot study highlights the potential impact of diet on function and QOL in MS.

LIFETIME PHYSICAL INACTIVITY IS ASSOCIATED WITH LUNG CANCER RISK AND MORTALITY

INTRODUCTION

Investigations of the independent associations of physical inactivity with cancer endpoints have been mounting in the epidemiological literature, in part due to the high prevalence of physical inactivity among cancer patients and to evidence that inactivity associates with carcinogenesis via pathways independent of obesity. Yet, physical inactivity is not currently recognized as a well-established risk or prognostic factor for lung cancer. As such, we examined the associations of lifetime physical inactivity with lung cancer risk and mortality in a hospital-based, case-control study.

PRESENTATION OF CASE

Materials and Methods: The analyses included data from 660 lung cancer patients and 1335 matched cancer-free controls. Multivariable logistic regression analyses were utilized to assess the association between lifetime physical inactivity and lung cancer risk, and Cox proportional hazards models were utilized to estimate the association between lifetime physical inactivity and mortality among lung cancer cases.Results: We observed a significant positive association between lifetime physical inactivity and lung cancer risk: [Odds ratio (OR)=2.23, 95% confidence interval (CI): 1.77-2.81]; the association remained significant among never smokers (OR=3.00, 95% CI:1.33-6.78) and non-smokers (OR=2.33, 95% CI: 1.79-3.02). We also observed a significant positive association between lifetime physical inactivity and lung cancer mortality [Hazard ratio (HR)=1.40, 95% CI: 1.14-1.71]; the association remained significant in non-smokers (HR=1.51, 95% CI: 1.16-1.95).

DISCUSSION/CONCLUSION

These data add to the body of evidence suggesting that physical inactivity is an independent risk and prognostic factor for cancer. Additional research utilizing prospectively collected data is needed to substantiate the current findings.

Coupling and optimisation of online nuclear magnetic resonance spectroscopy and mass spectrometry for process monitoring to cover the broad range of process concentration

Real time online monitoring of chemical processes can be carried out by a number of analytical techniques, including optical and vibrational spectroscopies, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). As each technique has unique advantages and challenges, combinations are an attractive option. The combination of a 500-MHz ¹ H NMR and a small footprint mass spectrometer to monitor a batch reaction at process concentration was investigated. The mass spectrometer was coupled into the flow path of an online reaction monitoring NMR. Reaction mixture was pumped from a 100-ml vessel to an NMR flow tube before returning to the vessel. Small aliquots were diverted into a sampling make-up flow using an active flow splitter and passed to the mass spectrometer. Advantages of the combination were observed. ¹ H NMR was ideal for quantitation of high level components, whereas MS showed a greater capability for detecting those at low level. In preliminary experiments MS produced a limited linear relationship with concentration (0.02% to 2% relative concentration, 0.01 mg/ml-1.25 mg/ml), because of signal saturation at the higher concentrations. NMR was unable to detect components below 0.1% relative to concentration maximum. Optimisation of sample transfer to the MS extended the linearity to 10% relative to the concentration maximum. Therefore, the combination of online NMR and MS allows both qualitative and quantitative analysis of reaction components over the full process range. The application of the combination was demonstrated by monitoring a batch chemical reaction and this is described. Copyright © 2016 John Wiley & Sons, Ltd.

Vitamin D3 intake modulates diaphragm but not peripheral muscle force in young mice

Recent data support an important role for vitamin D in respiratory health. We tested the hypothesis that dietary vitamin D3 (VD3) intake modulates diaphragm (DIA) strength. Four-week-old female A/J mice (n = 10/group) were randomized to receive diets containing 100 IU VD3/kg (low), 1,000 IU VD3/kg (reference), or 10,000 IU VD3/kg (pharmacologic). After 6 wk of dietary intervention, plasma 25-hydroxyvitamin D3 (25D3) levels, DIA and extensor digitorum longus (EDL) in vitro contractile properties, and fiber cross-sectional area (CSA) were measured. Myosin heavy chain (MHC) composition and Akt/Foxo3A growth signaling were studied in the DIA and tibialis anterior. Mice fed the low, reference, and pharmacologic diets had average 25D3 levels of 7, 21, and 59 ng/ml, respectively. Maximal DIA force, twitch force, and fiber CSA were reduced 26%, 28%, and 10% (P < 0.01), respectively, in mice receiving the low-VD3 diet compared with the reference and pharmacologic diets. EDL force parameters were unaltered by diet. Effects of VD3 intake on DIA force were not observed in mice that began dietary intervention at 12 wk of age. VD3 intake did not alter the MHC composition of the DIA, indicating that decreases in force and CSA in young mice were not due to a switch in fiber type. Paradoxically, low VD3 intake was associated with activation of anabolic signaling in muscle (hyperphosphorylation of Akt and Foxo3A and decreased expression of autophagy marker LC3). These studies identify a potential role of dietary VD3 in regulating DIA development and insulin sensitivity.

Electrochemical flow injection analysis of hydrazine in an excess of an active pharmaceutical ingredient: achieving pharmaceutical detection limits electrochemically

The quantification of genotoxic impurities (GIs) such as hydrazine (HZ) is of critical importance in the pharmaceutical industry in order to uphold drug safety. HZ is a particularly intractable GI and its detection represents a significant technical challenge. Here, we present, for the first time, the use of electrochemical analysis to achieve the required detection limits by the pharmaceutical industry for the detection of HZ in the presence of a large excess of a common active pharmaceutical ingredient (API), acetaminophen (ACM) which itself is redox active, typical of many APIs. A flow injection analysis approach with electrochemical detection (FIA-EC) is utilized, in conjunction with a coplanar boron doped diamond (BDD) microband electrode, insulated in an insulating diamond platform for durability and integrated into a two piece flow cell. In order to separate the electrochemical signature for HZ such that it is not obscured by that of the ACM (present in excess), the BDD electrode is functionalized with Pt nanoparticles (NPs) to significantly shift the half wave potential for HZ oxidation to less positive potentials. Microstereolithography was used to fabricate flow cells with defined hydrodynamics which minimize dispersion of the analyte and optimize detection sensitivity. Importantly, the Pt NPs were shown to be stable under flow, and a limit of detection of 64.5 nM or 0.274 ppm for HZ with respect to the ACM, present in excess, was achieved. This represents the first electrochemical approach which surpasses the required detection limits set by the pharmaceutical industry for HZ detection in the presence of an API and paves the wave for online analysis and application to other GI and API systems.

Measures of respiratory function correlate with fatigue in ambulatory persons with multiple sclerosis

PURPOSE

This article examines the association between measures of respiratory muscle function and fatigue in individuals with mild-to-moderate disability multiple sclerosis (MS).

METHODS

This was a cross-sectional study of 37 ambulatory volunteers with MS (28 F/9 M, 52.7 ± 10.2 years, Expanded Disability Status Scale [EDSS] = 3.5 ± 1.9). No patients withdrew from the study. Primary outcome variables included measures of respiratory function: maximal inspiratory (MIP) and expiratory pressures (MEP), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), maximal voluntary ventilation (MVV₁₂); and a self-reported measure of fatigue: the Modified Fatigue Impact Scale (MFIS). Secondary measures included 6-min walking test (6MWT), a timed stair climb, the Short Form (SF)-36, the Epworth Sleepiness Scale and the Physical Activity and Disability Scale (PADS).

RESULTS

Significant correlations were shown between expiratory muscle strength (MEP) and the MFIS total (p < 0.03, r = -0.362) and between MEP and physical fatigue scores (p < 0.03, r = -0.360), as well as between MVV₁₂ percent predicted (respiratory muscle endurance) and both the 6MWT (p = 0.045, r = 0.346) and the Epworth Sleepiness Scale (p = 0.006, r = 0.447).

CONCLUSIONS

Respiratory muscle performance is correlated with perceived fatigue (MFIS), whereas respiratory endurance correlated to reductions in physical function and sleep quality among individuals with mild-to-moderate severity MS. Implications for Rehabilitation Multiple sclerosis (MS) results in peripheral and respiratory muscle weakness and affected individuals report fatigue as one of their most disabling symptoms. Expiratory muscle strength was correlated with self-reported physical fatigue, while respiratory muscle endurance was correlated with functional performance and sleepiness. Respiratory muscle strength was not correlated with lung spirometry testing. These findings highlight the importance of considering the effects of respiratory muscle weakness when evaluating causes of fatigue among individuals with mild-to-moderate MS.

On-line monitoring of continuous flow chemical synthesis using a portable, small footprint mass spectrometer

For on-line monitoring of chemical reactions (batch or continuous flow), mass spectrometry (MS) can provide data to (1) determine the fate of starting materials and reagents, (2) confirm the presence of the desired product, (3) identify intermediates and impurities, (4) determine steady state conditions and point of completion, and (5) speed up process optimization. Recent developments in small footprint atmospheric pressure ionization portable mass spectrometers further enable this coupling, as the mass spectrometer can be easily positioned with the reaction system to be studied. A major issue for this combination is the transfer of a sample that is representative of the reaction and also compatible with the mass spectrometer. This is particularly challenging as high concentrations of reagents and products can be encountered in organic synthesis. The application of a portable mass spectrometer for on-line characterization of flow chemical synthesis has been evaluated by coupling a Microsaic 4000 MiD to the Future Chemistry Flow Start EVO chemistry system. Specifically, the Hofmann rearrangement has been studied using the on-line mass spectrometry approach. Sample transfer from the flow reactor is achieved using a mass rate attenuator (MRA) and a sampling make-up flow from a high pressure pump. This enables the appropriate sample dilution, transfer, and preparation for electrospray ionization. The capability of this approach to provide process understanding is described using an industrial pharmaceutical process that is currently under development. The effect of a number of key experimental parameters, such as the composition of the sampling make-up flow and the dilution factor on the mass spectrometry data, is also discussed.

Energy cost of breathing at depth: effect of respiratory muscle training

INTRODUCTION

Respiratory muscle training against resistance (RRMT) increases respiratory muscle strength and endurance as well as underwater swimming endurance. We hypothesized that the latter is a result of RRMT reducing the high energy cost of breathing at depth.

METHODS

Eight subjects breathed air in a hyperbaric chamber at 55 fsw, both before and after RRMT. They rested for 10 minutes, cycled on an ergometer for 10 minutes (100 W), rested for 10 minutes, and then, while still at rest, they voluntarily mimicked the breathing pattern recorded during the exercise (isocapnic simulated exercise ventilation, ISEV).

RESULTS

Post-RRMT values of V(E) at rest, exercise and ISEV were not different from those recorded pre-RRMT. Pre-RRMT minute-ventilation (V(E)) during ISEV was not different from the exercise ventilation (49.98 +/- 10.41 vs. 47.74 +/- 8.44 L/minute). The end-tidal PCO2 during ISEV and exercise were not different (44.26 +/- 2.54 vs. 44.49 +/- 4.49 mmHg) or affected by RRMT. Oxygen uptake (VO2) was 0.32 +/- 0.08 L/ minute at rest, 1.78 +/- 0.15 during exercise pre-RRMT, and not different post-RRMT. During ISEV, VO2 decreased significantly from pre-RRMT to post-RRMT (0.46 +/- 0.06 vs. 0.36 +/- 0.11 L/minute). Post-RRMT delta VO2/delta V(E) was significantly lower during ISEV than pre-RRMT (0.0094 +/- 0.0021 L/L vs. 0.0074 +/- 0.0023 L/L).

CONCLUSION

RRMT significantly reduced the energy cost of ventilation, measured as delta VO2/delta V(E) during ISEV, at a depth of 55 fsw. Whether this change was due to reduced work of breathing and/or increased efficiency of the respiratory muscles remains to be determined.

Molecular ions and protonated molecules observed in the atmospheric solids analysis probe analysis of steroids

Atmospheric pressure chemical ionisation (APCI) has often been used to ionise steroids in mass spectrometry, usually when interfaced to high-performance liquid chromatography (HPLC). However, in positive ion mode, a dehydrated protonated molecule is often observed with a loss of structural information. The recently introduced technique of atmospheric solids analysis probe (ASAP) has the advantage that the sample can be analysed directly and does not need to be interfaced to HPLC. Existing ionisation sources such as direct analysis in real time (DART) and desorption electrospray ionisation (DESI) have shown the advantage of direct analysis techniques in a variety of applications. ASAP can be performed on commercial atmospheric pressure ionisation (API) mass spectrometers with only simple modifications to API sources. The samples are vaporised by hot nitrogen gas from the electrospray desolvation heater and ionised by a corona discharge. A range of commercially available steroids were analysed by ASAP to investigate the mechanism of ionisation. ASAP analysis of steroids generally results in the formation of the parent molecular ion as either the radical cation M+* or the protonated molecule MH+. The formation of the protonated molecule is a result of proton transfer from ionised water clusters in the source. However, if the source is dry, then formation of the radical cation is the primary ionisation mechanism.

Aging increases upper airway collapsibility in Fischer 344 rats

The upper airway muscles play an important role in maintaining upper airway collapsibility, and the incidence of sleep-disordered breathing increases with age. We hypothesize that the increase in airway collapsibility with increasing age can be linked to changes in upper airway muscle mechanics and structure. Eight young (Y: 6 mo) and eight old (O: 30 mo) Fischer 344 rats were anesthetized and mechanically ventilated, and the pharyngeal pressure associated with flow limitation (Pcrit) was measured 1) with the hypoglossal (cnXII) nerve intact, 2) following bilateral cnXII denervation, and 3) during cnXII stimulation. With the cnXII intact, the upper airways of older rats were more collapsible compared with their younger counterparts [Pcrit = -7.1 +/- 0.6 (SE) vs. -9.5 +/- 0.7 cmH2O, respectively; P = 0.033]. CnXII denervation resulted in an increase in Pcrit such that Pcrit became similar in both groups (O: -4.2 +/- 0.5 cmH2O; Y: -5.4 +/- 0.5 cmH2O). In all rats, cnXII stimulation decreased Pcrit (less collapsible) in both groups (O: -11.3 +/- 1.0 cmH2O; Y: -10.2 +/- 1.0 cmH2O). The myosin heavy chain composition of the genioglossus muscle demonstrated a decrease in the percentage of the IIb isoform (38.3 +/- 2.5 vs. 21.7 +/- 1.7%; P < 0.001); in contrast, the sternohyoid muscle demonstrated an increase in the percentage of the IIb isoform (72.2 +/- 2.5 vs. 58.4 +/- 2.3%; P = 0.001) with age. We conclude that the upper airway becomes more collapsible with age and that the increase in upper airway collapsibility with age is likely related to altered neural control rather than to primary alterations in upper airway muscle structure and function.

Respiratory muscle training improves swimming endurance at depth

Respiratory muscle training (RMT) has been shown to improve divers swimming endurance at 4 feet of depth; however, its effectiveness at greater depths, where gas density and the work of breathing are substantially elevated has not been studied. The purpose of this study was to examine the effects of resistance respiratory muscle training (RRMT) on respiratory function and swimming endurance at 55 feet of depth (270.5 kPa). Nine male subjects (25.9 +/- 6.8 years) performed RRMT for 30 min/day, 5 d/ wk, for 4 wks. Pre- and Post RRMT, subjects swam against a pre-determined load (70% VO2 max) until exhausted. As indices of respiratory muscle strength, maximal inspiratory and expiratory pressures were measured before and immediately following the swims pre- and post-RRMT. These measurements showed that ventilation was significantly lower during the swims and, at comparable swim duration, that the respiratory muscles were considerably less fatigued following RRMT. The reduced ventilation was due to a lower breathing frequency following RRMT. The ventilatory changes following RRMT coincided with significantly increased swimming time to exhaustion (approximately 60%, 31.3 +/- 11.6 vs. 49.9 +/- 16.0 min, pre- vs. post-RRMT, p < 0.05). These results suggest respiratory muscle fatigue limits swimming endurance at depth as well as at the surface and RRMT improves performance.

Intermittent hypoxia reduces upper airway stability in lean but not obese Zucker rats

Obstructive sleep apnea involves intermittent periods of airway occlusions that lead to repetitive oxygen desaturations. Exposure to chronic intermittent hypoxia (IH) in rats increases diurnal blood pressure and alters skeletal muscle physiology. The impact of IH on upper airway muscle function is unknown. We hypothesize that IH exposure increases upper airway collapsibility in rats due to alterations of the muscles surrounding the upper airway. Lean and obese rats were exposed to cyclic alterations in O(2) levels (20.6%-5%) every 90 s, 8 h/day for 6 days/wk for 12 wk. Following the exposure period, arterial pressure was recorded via the tail artery in conscious unrestrained rats. Mean arterial pressure was increased in lean IH but not in obese IH-exposed Zucker rats (P < 0.05). The pharyngeal pressure associated with airway collapse (P(crit)) was measured under anesthesia during baseline conditions and then during supramaximal stimulation of the hypoglossal nerve (cnXII). Baseline P(crit) was more positive (more collapsible) in lean but not obese rats following 12 wk of IH (P < 0.05), while supramaximal stimulation of cnXII increased airway stability (decreased P(crit)) in both lean and obese Zucker rats following IH to levels that were similar to their respective room air controls. The in vitro peak tension and the expression of the individual myosin heavy chain isoforms from the upper airway muscles were unaltered following IH. We conclude that IH leads to increases in baseline collapsibility in lean Zucker rats exposed to IH by nonmyogenic mechanisms.

Systemic Administration of Serotonin 2A/2C Agonist Improves Upper Airway Stability in Zucker Rats

The effects of [+/-]-2,5-dimethoxy-4-iodoaminophentamine, a serotonin(2A/2C) receptor agonist, on pharyngeal airflow mechanics were examined in isoflurane-anesthetized lean and obese Zucker rats. The pharyngeal pressure associated with flow limitation, maximum inspiratory flow, oronasal resistance, genioglossus muscle activity, and arterial blood pressure (BP) were measured before and after the intravenous administration of the agonist. A robust activation of the genioglossus muscle in all lean and obese rats was associated with decreased upper airway (UA) collapsibility (p < 0.05), unchanged maximum flow, and increased oronasal resistance (p < 0.05) in both groups. The changes in UA mechanics and BP after the drug were similar in lean and obese rats. The serotonin agonist had no effect on UA mechanics in a group of paralyzed (pancuronium bromide) rats, despite similar elevations in BP. There was a smaller decrease (p < 0.05) in UA collapsibility that was also associated with increased upstream resistance when the drug was administered after bilateral hypoglossal nerve transection. We conclude that systemic administration of a serotonin(2A/2C) receptor agonist improves UA collapsibility predominantly, but not exclusively, via stimulation of the hypoglossal nerves and also increases upstream resistance, at least in part, through activation of nonhypoglossal motoneuronal pools innervating the UA muscles.

Exercise delays the hypoxic thermal response in rats

Exercise exacerbates acute mountain sickness. In infants and small mammals, hypoxia elicits a decrease in body temperature (Tb) [hypoxic thermal response (HTR)], which may protect against hypoxic tissue damage. We postulated that exercise would counteract the HTR and promote hypoxic tissue damage. Tb was measured by telemetry in rats (n = 28) exercising or sedentary in either normoxia or hypoxia (10% O2, 24 h) at 25 degrees C ambient temperature (Ta). After 24 h of normoxia, rats walked at 10 m/min on a treadmill (30 min exercise, 30 min rest) for 6 h followed by 18 h of rest in either hypoxia or normoxia. Exercising normoxic rats increased Tb ( degrees C) vs. baseline (39.68 +/- 0.99 vs. 38.90 +/- 0.95, mean +/- SD, P < 0.05) and vs. sedentary normoxic rats (38.0 +/- 0.09, P < 0.05). Sedentary hypoxic rats decreased Tb (36.15 +/- 0.97 vs. 38.0 +/- 0.36, P < 0.05) whereas Tb was maintained in the exercising hypoxic rats during the initial 6 h of exercise (37.61 +/- 0.55 vs. 37.72 +/- 1.25, not significant). After exercise, Tb in hypoxic rats reached a nadir similar to that in sedentary hypoxic rats (35.05 +/- 1.69 vs. 35.03 +/- 1.32, respectively). Tb reached its nadir significantly later in exercising hypoxic vs. sedentary hypoxic rats (10.51 +/- 1.61 vs. 5.36 +/- 1.83 h, respectively; P = 0.002). Significantly greater histopathological damage and water contents were observed in brain and lungs in the exercising hypoxic vs. sedentary hypoxic and normoxic rats. Thus exercise early in hypoxia delays but does not prevent the HTR. Counteracting the HTR early in hypoxia by exercise exacerbates brain and lung damage and edema in the absence of ischemia.

Adaptation of upper airway muscles to chronic endurance exercise

We tested the hypothesis that chronic endurance exercise is associated with the recruitment of four major upper airway muscles (genioglossus, digastric, sternohyoid, and omohyoid) and results in an increased oxidative capacity and a fast-toward-slow shift in myosin heavy chain (MHC) isoforms of these muscles. Female Sprague-Dawley rats (n = 8; 60 days old) performed treadmill exercises for 12 weeks (4 days/week; 90 minutes/day). Age-matched sedentary female rats (n = 10) served as control animals. Training was associated with an increase (p < 0.05) in the activities of both citrate synthase and superoxide dismutase in the digastric and sternohyoid muscles, as well as in the costal diaphragm. Compared with the control animals, Type I MHC content increased (p < 0.05) and Type IIb MHC content decreased (p < 0.05) in the digastric, sternohyoid, and diaphragm muscles of exercised animals. Training did not alter (p > 0.05) MHC phenotype, oxidative capacity, or antioxidant enzyme activity in the omohyoid or genioglossus muscle. These data indicate that endurance exercise training is associated with a fast-to-slow shift in MHC phenotype together with an increase in both oxidative and antioxidant capacity in selected upper airway muscles. It seems possible that this exercise-mediated adaptation is related to the recruitment of these muscles as stabilizers of the upper airway.

Role of nitric oxide in thermoregulation and hypoxic ventilatory response in obese Zucker rats

To examine the role of nitric oxide (NO) on thermoregulation and control of breathing in obesity, awake obese and age-matched lean Zucker (Z) rats underwent a sustained hypoxic challenge. Body temperature (Tb), oxygen consumption (V O(2)) and ventilation (V E) were measured during room air and during 30-min of hypoxia (10% O(2)) after intraperitoneal administration of either 100 mg/kg of N(G)-nitro-L-arginine methyl ester (L-NAME), a nonspecific NOS inhibitor, 25 mg/kg of 7-nitroindazole (7-NI), a selective neuronal NOS inhibitor, or equal volume of vehicle (dimethyl sulfoxide: DMSO) as control. Tb in obese rats during room air was significantly lower than that of lean rats. Hypoxia induced a more pronounced drop in Tb and V O(2) in lean rats than in obese rats. Tb in lean Z rats dropped significantly by approximately 0.2 degrees C after L-NAME and, more markedly, by approximately 1.1 degrees C after 7-NI compared with control during room air, whereas Tb in obese Z rats was unaffected. L-NAME and 7-NI attenuated hypoxia-induced hypothermia or hypometabolism in lean rats, but not in obese rats. Lean rats exhibited an abrupt increase in V E in response to hypoxia followed by a gradual decline in V E. In contrast, obese rats displayed an initial increase in V E that plateaued during sustained hypoxia. Both L-NAME and 7-NI induced marked decreases in V E during room air and hypoxia compared with control lean rats, whereas V E was virtually unaffected by either agent in obese rats. The present results suggest that the blunted thermoregulatory and ventilatory responses to hypoxia in obese Z rats may be attributed to reduced activity of NOS in the central nervous system.

Sporadic paroxysmal exercise induced dystonia: report of a case and review of the literature

Sporadic paroxysmal exercise induced dystonia (PEID) is a rare condition. So far only fifteen cases have been reported in the world literature. It is characterised by dystonic posture on prolonged exercise, which gets relieved with rest. In general, these are refractory to medical treatment. We report one such case, along with review of the literature. The lower limbs were spared and only right shoulder was tucked up with the head turning to right side. The duration of exercise necessary to bring out the dystonic posture gradually diminished with time, a feature not reported previously.