Expression of α1 adrenergic receptor subtypes by afferent fibers that innervate rat masseter muscle

Aims

In temporomandibular disorders sufferers, muscle pain is more severe in individuals who have undergone a traumatic stress. Why stress exacerbates masticatory muscle pain in these individuals is not known. One possibility is that under conditions of stress there is an interaction between the sympathetic and sensory nervous systems. This study investigated whether trigeminal ganglion neurons that innervate the masseter muscle express α1 adrenergic receptor subtypes to identify whether a direct interaction between the sympathetic and sensory nervous systems is feasible.

Methods

Masseter muscle ganglion neurons were identified by injection of the fluorescent dye fast blue into the masseter muscle of 4 Sprague Dawley rats (2 male, 2 female). Trigeminal ganglion sections were stained for α1a, α1b or α1d adrenergic receptors, as well as the transient receptor potential vanilloid 1 (TrpV1) receptor. Sections were examined with a Leica confocal microscope. The percent of masseter ganglion neurons expressing each receptor was calculated.

Results

Masseter muscle ganglion neurons expressed α1a(29 ± 9%), α1b (34 ± 4%) and α1d (19 ± 13%) adrenergic receptors. Expression of all three α1 receptor subtypes was higher in female rats than in male rats. Expression of α1b receptors was more commonly found on larger diameter masseter ganglion neurons. Overall 11±3% of masseter ganglion neurons expressed the TrpV1 receptor, which suggests they served a nociceptive function. The TrpV1 receptor was co-expressed by about ~10% of α1a and α1b receptor positive masseter ganglion neurons.

Conclusions

Afferent fibers that innervate the masseter muscle express all three α1 adrenergic receptor subtypes. Agonists at the α1 receptor have been previously shown to depolarize trigeminal ganglion neurons, which suggests that activation of these receptors on masseter muscle afferents would be excitatory. The expression of α1 receptors by putative nociceptors that innervate the masseter may permit a direct interaction between the sensory and sympathetic system that contributes to pain in this muscle.

In Vitro Metabolism of Oprozomib, an Oral Proteasome Inhibitor: Role of Epoxide Hydrolases and Cytochrome P450s

Oprozomib is an oral proteasome inhibitor currently under investigation in patients with hematologic malignancies or solid tumors. Oprozomib elicits potent pharmacological actions by forming a covalent bond with the active site N-terminal threonine of the 20S proteasome. Oprozomib has a short half-life across preclinical species and in patients due to systemic clearance via metabolism. Potential for drug-drug interactions (DDIs) could alter the exposure of this potent therapeutic; therefore, a thorough investigation of pathways responsible for metabolism is required. In the present study, the major drug-metabolizing enzyme responsible for oprozomib metabolism was identified in vitro. A diol of oprozomib was found to be the predominant metabolite in human hepatocytes, which formed via direct epoxide hydrolysis. Using recombinant epoxide hydrolases (EHs) and selective EH inhibitors in liver microsomes, microsomal EH (mEH) but not soluble EH (sEH) was found to be responsible for oprozomib diol formation. Coincubation with 2-nonylsulfanyl-propionamide, a selective mEH inhibitor, resulted in a significant decrease in oprozomib disappearance (>80%) with concurrent complete blockage of diol formation in human hepatocytes. On the contrary, a selective sEH inhibitor did not affect oprozomib metabolism. Pretreatment of hepatocytes with the pan-cytochrome P450 (P450) inhibitor 1-aminobenzotriazole resulted in a modest reduction (∼20%) of oprozomib metabolism. These findings indicated that mEH plays a predominant role in oprozomib metabolism. Further studies may be warranted to determine whether drugs that are mEH inhibitors cause clinically significant DDIs with oprozomib. On the other hand, pharmacokinetics of oprozomib is unlikely to be affected by coadministered P450 and sEH inhibitors and/or inducers.

Relationship between physical activity and hip pain in persons with and without cam or pincer morphology: a population-based case-control study

OBJECTIVES

The purpose of the study was to determine if physical activity (PA) is a risk factor for persistent or recurrent hip pain in young and middle-aged persons with and without radiographic findings of cam or pincer morphology (CPM).

METHODS

A population sample of persons aged 20-49 with (cases) and without (controls) hip pain in Metro Vancouver, Canada, was selected through random digit dialing (RDD). Self-reported PA was expressed as average energy expenditure (MET-hours) per year, over lifetime. CPM was defined as alpha angle >55°, lateral centre edge angle (LCE) >40°, or positive cross-over sign.

RESULTS

Data were obtained for 500 subjects, 269 cases and 231 controls. Prevalence of radiographic CPM was 49% in the cases and 44% in the controls. In a logistic regression model adjusted for age, gender and CPM, total lifetime PA, including occupational, domestic and recreational activities, was significantly associated with hip pain (Odds ratio (OR) 1.30 per 1000 MET-hours, 95% CI 1.15-1.38). The effect of total PA was observed in those with CPM (1.44, 1.17-1.78) and without CPM (1.23, 1.04-1.45). For domestic activities, the association was seen only in those with CPM (significant interaction). When PA was categorized into quartiles, higher levels of PA were associated with a greater risk of pain.

CONCLUSIONS

PA, as measured by average energy expenditure over lifetime is a risk factor for hip pain in young and middle-aged persons. For some activities, the risk is likely increased in persons with radiographic evidence of CPM.

Specificity of Protein Covalent Modification by the Electrophilic Proteasome Inhibitor Carfilzomib in Human Cells

Carfilzomib (CFZ) is a second-generation proteasome inhibitor that is Food and Drug Administration and European Commission approved for the treatment of relapsed or refractory multiple myeloma. CFZ is an epoxomicin derivative with an epoxyketone electrophilic warhead that irreversibly adducts the catalytic threonine residue of the β5 subunit of the proteasome. Although CFZ produces a highly potent, sustained inactivation of the proteasome, the electrophilic nature of the drug could potentially produce off-target protein adduction. To address this possibility, we synthesized an alkynyl analog of CFZ and investigated protein adduction by this analog in HepG2 cells. Using click chemistry coupled with streptavidin based IP and shotgun tandem mass spectrometry (MS/MS), we identified two off-target proteins, cytochrome P450 27A1 (CYP27A1) and glutathione S-transferase omega 1 (GSTO1), as targets of the alkynyl CFZ probe. We confirmed the adduction of CYP27A1 and GSTO1 by streptavidin capture and immunoblotting methodology and then site-specifically mapped the adducts with targeted MS/MS methods. Although CFZ adduction of CYP27A1 and GSTO1 in vitro decreased the activities of these enzymes, the small fraction of these proteins modified by CFZ in intact cells should limit the impact of these off-target modifications. The data support the high selectivity of CFZ for covalent modification of its therapeutic targets, despite the presence of a reactive electrophile. The approach we describe offers a generalizable method to evaluate the safety profile of covalent protein-modifying therapeutics.

Abstract P1-07-10: Increasing population rates of in-situ breast cancer [DCIS] are associated with reduced breast cancer (BrCa) mortality. A case for screening mammography and "overdiagnosis" linked to outcome benefits

INTRODUCTION:

Following the first phase of this project [Ref 1], we correlate here the rates of DCIS with BrCaMOR, in two regions of Canada - British Columbia [BC] and Atlantic Provinces [Atl.P].

We previously reported higher compliance in screening mammography [ScreenMam] and therapeutic [TH*] guidelines [GUIDELINES] for both DCIS and invasive BrCa in BC compared with Atl.P [Ref. 2].

METHODS: Annual age-specific rates [cases / 100,000 population] of DCIS, and BrCaMOR between BC vs Atl.P, were obtained for 17 age groups of 5 years (years 0-4 to 85+) and averaged each 5-year period from 1975-1979 up to 2005-2009. To compare age distribution, DCIS rates and BrCaMOR between the two regions, we selected four birth cohorts, age 30-34, 35-39, 40-44 and 45-49 in 1975-1979. From those, we tabulated the DCIS incidence and BrCaMOR for each birth cohort when they reached ages 50-54 and 60-64. We assumed that the rates of DCIS reflect annual ScreenMam practices.

Data were obtained from the Public Health Agency of Canada based on the Canadian Cancer Registry database at Statistics Canada.

RESULTS [N/100,000 population]British ColumbiaAtlantic ProvincesAge / years DCISBrCaMORDCISBrCaMORAge 50 â– 54  1980-8413.152.24.056.41985-8921.246.68.056.11990â–9429.244.421.449.91995â–9945.543.830.050.1Age 60â – 64  1990-9428.072.123.186.21995-9949.361.935.276.62000-0449.365.845.669.42005â–0951.453.141.059.4

CONCLUSIONS:

1. Our study shows across all age cohorts higher rates of DCIS and lower BrCaMOR in BC compared to Atl.P - results consistent with higher ScreenMam rates in BC than Atl.P.

2. These data are compatible with the concept that a higher diagnostic rate for early lesions such as DCIS [i.e. frequently designated as "Overdiagnosis"] by ScreenMam, and subsequent earlier Guideline TH*, contributes to lower BrCaMOR.

*TH Guidelines: surgery, radiation, Tamoxifen for DCIS; and the same + chemotherapy for early invasive disease.

Citation Format: Ragaz J, Qian H, Shakeraneh S, Fox J, Wilson KS, Simpson JS, Yoon J-Y, Wong H. Increasing population rates of in-situ breast cancer [DCIS] are associated with reduced breast cancer (BrCa) mortality. A case for screening mammography and "overdiagnosis" linked to outcome benefits. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-10.

References:

1. J. Ragaz, H. Wong, H. Qian, J.Fox, K. Wilson, A. Coldman: Cancer Research, May 1, 2015 75; P3-07-28

2. J. Ragaz, H. Wong, H. Qian: Cancer Research Feb 2010; 69(24 Supplement):2063-2063.

Abstract P5-15-07: Knowledge of oncotype Dx recurrence score increases confidence and concordance in adjuvant decisions of U.K. oncologists

Introduction

The addition of Oncotype Dx Recurrence Score (RS) to the assessment of patients with ER positive, HER2 negative, node negative breast cancer has led to a reduction in the use of adjuvant chemotherapy. However, crude measurement of this reduction masks a more complex scenario. Prior to the introduction of routine Oncotype DX testing by NHS England, we wished to explore in more detail the potential impact of the knowledge of the RS on the therapeutic discussion. This study analyses the impact of RS on the adjuvant therapy recommendations within a UK Cancer Centre. In particular, it examines how the degree of certainty the oncologist has about the best option changes with knowledge of RS and how this influences concordance of decision making between oncologists.

Methods

A panel of five breast oncologists reviewed 50 consecutive cases, collected from November 2012 until November 2014, across two hospitals. Oncologists allocated each case to one of four treatment categories: chemotherapy recommended (CRec), chemotherapy discussed with a bias towards recommended (CDis), chemotherapy discussed with a bias toward endocrine therapy alone (EDis) or endocrine therapy only advised (ERec). The cases were analysed blindly and in random order without and with RS . The degree to which knowledge of RS altered treatment recommendation was analyzed. Other outcomes included the proportion of patients who were scored ERec compared with any other outcome, the trend towards definitive recommendations, the impact of RS on concordant decision making and the degree to which outcome was stratified by RS result. Chi squared and Spearman's coefficient statistical tests were used in analysis.

Results

Knowledge of the RS altered the recommended treatment category in 66.7% of cases (p<0.001).

Alterations in treatment recommendations in response to Oncotype Recurrence Score in addition to pathological parameters CRec (n)CDis (n)EDis (n)ERec (n)Without RS2% (1)40% (20)52% (26)6% (3)With RS12% (6)16% (8)26% (13)46% (23)

Overall, RS correlated significantly with treatment recommendation. Oncologists were confident to recommend endocrine therapy alone in 46% of patients when RS was known compared with only 6% of patients without RS. Complete concordance between oncologists increased with the knowledge of RS from 14% to 64%.

Conclusion

Discussion of adjuvant chemotherapy with patients who have ER positive, HER2 negative, node negative breast cancer can be complex and, at times, confusing for the patient, leading to increased distress. This study shows that, in addition to the previously recognised reduction in overall use of chemotherapy, the knowledge of the RS increased the proportion of patients for whom the oncologist felt confident in making a firm treatment recommendation. An added benefit was to increase concordance between different oncologists compared to that achieved when relying on standard pathological features.

Citation Format: Kiernan T, Olsson-Brown AC, Innes H, Holcombe C, Thorp N, O'Hagan J, Wong H, Palmieri C, O'Reilly S. Knowledge of oncotype Dx recurrence score increases confidence and concordance in adjuvant decisions of U.K. oncologists. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-15-07.

Postdischarge mortality in children with acute infectious diseases: derivation of postdischarge mortality prediction models

OBJECTIVES

To derive a model of paediatric postdischarge mortality following acute infectious illness.

DESIGN

Prospective cohort study.

SETTING

2 hospitals in South-western Uganda.

PARTICIPANTS

1307 children of 6 months to 5 years of age were admitted with a proven or suspected infection. 1242 children were discharged alive and followed up 6 months following discharge. The 6-month follow-up rate was 98.3%.

INTERVENTIONS

None.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was postdischarge mortality within 6 months following the initial hospital discharge.

RESULTS

64 children died during admission (5.0%) and 61 died within 6 months of discharge (4.9%). Of those who died following discharge, 31 (51%) occurred within the first 30 days. The final adjusted model for the prediction of postdischarge mortality included the variables mid-upper arm circumference (OR 0.95, 95% CI 0.94 to 0.97, per 1 mm increase), time since last hospitalisation (OR 0.76, 95% CI 0.61 to 0.93, for each increased period of no hospitalisation), oxygen saturation (OR 0.96, 95% CI 0.93 to 0·99, per 1% increase), abnormal Blantyre Coma Scale score (OR 2.39, 95% CI 1·18 to 4.83), and HIV-positive status (OR 2.98, 95% CI 1.36 to 6.53). This model produced a receiver operating characteristic curve with an area under the curve of 0.82. With sensitivity of 80%, our model had a specificity of 66%. Approximately 35% of children would be identified as high risk (11.1% mortality risk) and the remaining would be classified as low risk (1.4% mortality risk), in a similar cohort.

CONCLUSIONS

Mortality following discharge is a poorly recognised contributor to child mortality. Identification of at-risk children is critical in developing postdischarge interventions. A simple prediction tool that uses 5 easily collected variables can be used to identify children at high risk of death after discharge. Improved discharge planning and care could be provided for high-risk children.

Projecting the direct cost burden of osteoarthritis in Canada using a microsimulation model

OBJECTIVES

To estimate the future direct cost of OA in Canada using a population-based health microsimulation model of osteoarthritis (POHEM-OA).

METHODS

We used administrative health data from the province of British Columbia (BC), Canada, a survey of a random sample of BC residents diagnosed with OA (Ministry of Health of BC data), Canadian Institute of Health Information (CIHI) cost data and literature estimates to populate a microsimulation model. Cost components associated with pharmacological and non-pharmacological treatments, total joint replacement (TJR) surgery, as well as use of hospital resources and management of complications arising from the treatment of osteoarthritis (OA) were included. Future costs were then simulated using the POHEM-OA model to construct profiles for each adult Canadian.

RESULTS

From 2010 to 2031, as the prevalence of OA is projected to increase from 13.8% to 18.6%, the total direct cost of OA is projected to increase from $2.9 billion to $7.6 billion, an almost 2.6-fold increase (in 2010 $CAD). From the highest to the lowest, the cost components that will constitute the total direct cost of OA in 2031 are hospitalization cost ($2.9 billion), outpatient services ($1.2 billion), alternative care and out-of-pocket cost categories ($1.2 billion), drugs ($1 billion), rehabilitation ($0.7 billion) and side-effect of drugs ($0.6 billion).

CONCLUSIONS

Projecting the future trends in the cost of OA enables policy makers to anticipate the significant shifts in its distribution of burden in the future.