The gut-microbiome-endocannabinoid axis and anhedonia/amotivation: A mediation analysis in a general population cohort

Introduction

General-population studies investigating the biological correlates of anhedonia/amotivation might be informative for treatment breakthroughs for a number of clinical conditions. Reduced gut-microbial diversity might lead to an anhedonic/amotivational syndrome (“sickness behaviour”). However, how gut-microbial diversity contribute to this clinical phenotype is a key gap in knowledge. We hypothesised the endocannabinoid system would be at play.

Objectives

We tested the hypothesis that the endocannabinoid system mediates the association between gut-microbial diversity and anhedonia/amotivation

Methods

Secondary data analysis on 786 volunteer twins (TwinsUK). Measures of gut-microbiome, faecal endocannabinoid metabolites, and anhedonia/amotivation were collected over five years. To test our hypothesis we used a multilevel mediation model using alpha diversity as predictor, faecal levels of the endocannabinoid palmitoylethanolamide (PEA) as mediator, and anhedonia/amotivation as outcome. Analyses were adjusted for obesity, diet, antidepressants, and sociodemographic covariates.

Results

Mean age was 65.2±7.6; 27% were obese and 4.7% were on antidepressants. Alpha diversity was significantly associated with anhedonia/amotivation (β=-0.37; 95%CI: -0.71 to -0.03; P=0.03). Faecal PEA levels mediated this association: the indirect effect was significant (β=-0.13; 95%CI: -0.24 to -0.01; P=0.03), as was the total effect (β=-0.38; 95%CI: -0.72 to -0.04; P=0.03). The direct effect of alpha diversity on anhedonia/amotivation was attenuated fully

Conclusions

We provided the first evidence showing that the association between gut-microbial features and anhedonia/amotivation is mediated by the endocannabinoid system. These findings shed light on a new therapeutic target in an area of unmet clinical need.

Disclosure

No significant relationships.

Systematic variation in food web body-size structure linked to external subsidies

The relationship between body mass (M) and size class abundance (N) depicts patterns of community structure and energy flow through food webs. While the general assumption is that M and N scale linearly (on log-log axes), nonlinearity is regularly observed in natural systems, and is theorized to be driven by nonlinear scaling of trophic level (TL) with M resulting in the rapid transfer of energy to consumers in certain size classes. We tested this hypothesis with data from 31 stream food webs. We predicted that allochthonous subsidies higher in the web results in nonlinear M-TL relationships and systematic abundance peaks in macroinvertebrate and fish size classes (latter containing salmonids), that exploit terrestrial plant material and terrestrial invertebrates, respectively. Indeed, both M-N and M-TL significantly deviated from linear relationships and the observed curvature in M-TL scaling was inversely related to that observed in M-N relationships. Systemic peaks in M-N, and troughs in M-TL occurred in size classes dominated by generalist invertebrates, and brown trout. Our study reveals how allochthonous resources entering high in the web systematically shape community size structure and demonstrates the relevance of a generalized metabolic scaling model for understanding patterns of energy transfer in energetically 'open' food webs.

Diagnosing hereditary cancer predisposition in men with prostate cancer

PURPOSE

We describe the pathogenic variant spectrum and identify predictors of positive results among men referred for clinical genetic testing for prostate cancer.

METHODS

One thousand eight hundred twelve men with prostate cancer underwent clinical multigene panel testing between April 2012 and September 2017. Stepwise logistic regression determined the most reliable predictors of positive results among clinical variables reported on test requisition forms.

RESULTS

A yield of 9.4-12.1% was observed among men with no prior genetic testing. In this group, the positive rate of BRCA1 and BRCA2 was 4.6%; the positive rate for the mismatch repair genes was 2.8%. Increasing Gleason score (odds ratio [OR] 1.19; 95% confidence interval [CI] 0.97-1.45); personal history of breast or pancreatic cancer (OR 3.62; 95% CI 1.37-9.46); family history of breast, ovarian, or pancreatic cancer (OR 2.32 95% CI 1.48-3.65); and family history of Lynch syndrome-associated cancers (OR 1.97; 95% CI 1.23-3.15) were predictors of positive results.

CONCLUSION

These results support multigene panel testing as the primary genetic testing approach for hereditary prostate cancer and are supportive of recommendations for consideration of germline testing in men with prostate cancer. Expanding the criteria for genetic testing should be considered as many pathogenic variants are actionable for treatment of advanced prostate cancer.

A century of educational inequality in the United States

The "income inequality hypothesis" holds that rising income inequality affects the distribution of a wide range of social and economic outcomes. Although it is often alleged that rising income inequality will increase the advantages of the well-off in the competition for college, some researchers have provided descriptive evidence at odds with the income inequality hypothesis. In this paper, we track long-term trends in family income inequalities in college enrollment and completion ("collegiate inequalities") using all available nationally representative datasets for cohorts born between 1908 and 1995. We show that the trends in collegiate inequalities moved in lockstep with the trend in income inequality over the past century. There is one exception to this general finding: For cohorts at risk for serving in the Vietnam War, collegiate inequalities were high, while income inequality was low. During this period, inequality in college enrollment and completion was significantly higher for men than for women, suggesting a bona fide "Vietnam War" effect. Aside from this singular confounding event, a century of evidence establishes a strong association between income and collegiate inequality, providing support for the view that rising income inequality is fundamentally changing the distribution of life chances.

The Use of Mindfulness to Increase Participation in Meaningful Occupations for Individuals With Chronic Pain

Date Presented 03/27/20

Chronic pain impacts multiple aspects of an individual’s life, including participation in meaningful occupations. Mindfulness techniques such as yoga, meditation, journaling, and variations on mindfulness-based stress-reduction (MBSR) programs have been shown to positively affect the relationship an individual has with chronic pain, thereby increasing opportunities for participation in meaningful occupations.

Primary Author and Speaker: Michelle Jackson

Contributing Authors: Sarbinaz Bekmuratova

Patient deprivation and perceived scan burden negatively impact the quality of whole-body MRI

AIM

To evaluate the association between the image quality of cancer staging whole-body magnetic resonance imaging (WB-MRI) and patient demographics, distress, and perceived scan burden.

MATERIALS AND METHODS

A sample of patients recruited prospectively to multicentre trials comparing WB-MRI with standard scans for staging lung and colorectal cancer were invited to complete two questionnaires. The baseline questionnaire, administered at recruitment, collated data on demographics, distress and co-morbidity. The follow-up questionnaire, completed after staging investigations, measured perceived WB-MRI scan burden (scored 1 low to 7 high). WB-MRI anatomical coverage, and technical quality was graded by a radiographic technician and grading combined to categorise the scan as "optimal", "sub-optimal" or "degraded". A radiologist categorised 30 scans to test interobserver agreement. Data were analysed using the chi-square, Fisher's exact, t-tests, and multinomial regression.

RESULTS

One hundred and fourteen patients were included in the study (53 lung, 61 colorectal; average age 65.3 years, SD=11.8; 66 men [57.9%]). Overall, 45.6% (n=52), scans were classified as "optimal" quality, 39.5% (n=45) "sub-optimal", and 14.9% (n=17) as "degraded". In adjusted analyses, greater deprivation level and higher patient-reported scan burden were both associated with a higher likelihood of having a sub-optimal versus an optimal scan (odds ratio [OR]: 4.465, 95% confidence interval [CI]: 1.454 to 13.709, p=0.009; OR: 1.987, CI: 1.153 to 3.425, p=0.013, respectively). None of the variables predicted the likelihood of having a degraded scan.

CONCLUSIONS

Deprivation and patients' perceived experience of the WB-MRI are related to image quality. Tailored protocols and individualised patient management before and during WB-MRI may improve image quality.

African-Caribbean Cancer Consortium Scientific and Training Conference 2017

The sixth International African-Caribbean Cancer Consortium (AC3) Conference was held 6-9 October 2017 in Miami, Florida, U.S.A. The conference was open to all researchers, trainees, clinical and public health professionals, and community members, and served as an international hub for the United States, the Caribbean, and Africa. Sessions included AC3 collaboration meetings, cancer surveillance and research skills training workshops, and a community cancer prevention conference.

6LiF:ZnS(Ag) Neutron Detector Performance Optimized Using Waveform Recordings and ROC Curves

We used Gaussian separation and receiver operating characteristic (ROC) curves to optimize the neutron sensitivity and gamma rejection of an ultra-thin ⁶LiF:ZnS(Ag)-scintillator-based neutron detector paired with a silicon photomultiplier (SiPM). We recorded the waveforms while operating the detector in a monochromatic cold neutron beam and in the presence of isotopic ¹³⁷Cs and ⁶⁰Co gamma sources. We used a two-window charge comparison (CC) pulse-shape discrimination (PSD) technique to distinguish the neutron capture events from other types of signals. By feeding the recorded waveforms through variants of this algorithm, it was possible to optimize the duration of the integration windows [(0-100 ns) for the prompt window and (100-2300 ns)] for the delayed window. We then computed the detector's ROC curve from waveform recordings and compared that with the experimental performance. We also used this procedure to compare a series of detector configurations to select the optimal bias voltage for the SiPM photosensor.

Understanding OT Practitioners’ Confidence in Treating Adolescents With Mental-Health Trauma (MHT) History

Date Presented 04/04/19

Adolescents with mental-health trauma (MHT) history face many challenges, and increasing OT providers’ knowledge and confidence in MHT treatment may improve both advocacy for OT role in MHT and program efficacy. The current study examined feasibility and effectiveness of using a brief informational infographic to increase the confidence, knowledge, and willingness of OT providers in working with adolescents with MHT history.

Primary Author and Speaker: Jamelle Brownlee

Additional Authors and Speakers: Michelle Jackson, Anna Quigg

Contributing Authors: Joanna Cruz, Katherina Zumalt, Stacy Buckingham-Howes

Solar angle of the distal phalanx is associated with scintigraphic evidence of subchondral bone injury in the palmar/plantar aspect of the third metacarpal/tarsal condyles in Thoroughbred racehorses

BACKGROUND

Subchondral bone injury at the palmar/plantar aspect of the condyles of the third metacarpal/metatarsal bone (MC/MT3) commonly causes lameness and poor performance in racehorses. Injury occurs due to repetitive loading, the magnitude of which may be influenced by the position of the distal phalanx relative to the ground surface, i.e. the solar angle. The association of solar angle and injury at the palmar/plantar condyles of distal MC/MT3 therefore warrants investigation.

OBJECTIVES

Investigate the relationship between solar angle and radiopharmaceutical uptake at the palmar/plantar aspect of distal MC/MT3 on scintigraphic images of racehorses.

STUDY DESIGN

Retrospective case-controlled study.

METHODS

Scintigraphic images of Thoroughbred racehorses presented for poor performance or lameness were graded for intensity of radiopharmaceutical uptake in the palmar/plantar aspect of distal MC/MT3. Solar angle was graded (positive, neutral or negative), referring to the angle of the solar plane of the distal phalanx relative to the ground surface. Repeatability of solar angle (n = 1226 limbs) and agreement with objective radiographic evaluation (n = 52 limbs) were evaluated. Prescintigraphy performance data were collected from race records. Associations between solar angle, performance and radiopharmaceutical uptake were investigated using multivariable logistic regression.

RESULTS

Repeatability of scintigraphic solar angle grading (κ = 0.89, 95% CI 0.87-0.91) and agreement of scintigraphic and radiographic solar angle (κ = 0.88, 95% CI 0.75-0.97) were excellent. Horses that performed best prior to presentation were more likely to have both greater radiopharmaceutical uptake and a neutral/negative solar angle. When controlling for prior performance, horses with neutral/negative forelimb solar angle were twice as likely to have moderate/marked radiopharmaceutical uptake than horses with positive solar angle (P<0.02). Horses with negative hindlimb solar angle were six times more likely to have moderate/marked radiopharmaceutical uptake than horses with positive/neutral solar angle (P<0.001).

MAIN LIMITATIONS

Population bias due to preselected hospital population.

CONCLUSIONS

Both solar angle and race performance are independently associated with increased bone activity in the palmar/plantar aspect of the third metacarpal/tarsal condyles. The Summary is available in Portuguese - see Supporting Information.

A Psychosexual Rehabilitation Booklet Increases Vaginal Dilator Adherence and Knowledge in Women Undergoing Pelvic Radiation Therapy for Gynaecological or Anorectal Cancer: A Randomised Controlled Trial

AIMS

Women treated with pelvic radiation therapy (PRT) for gynaecological or anorectal cancer report a high number of sexual problems and unmet post-treatment psychosexual information needs. Currently, there is suboptimal adherence to recommended rehabilitation aids, such as vaginal dilators, and a paucity of resources to facilitate post-radiation rehabilitation and reduce distress in this population. This randomised controlled trial aimed to evaluate the effectiveness of a study-developed psychosexual rehabilitation booklet in this setting.

MATERIALS AND METHODS

Eighty-two women scheduled for PRT to treat gynaecological/anorectal cancer were randomised to receive the intervention booklet (n = 44) or standard information materials (n = 38). Self-report questionnaires administered at pre-treatment baseline and at 3, 6 and 12 months post-treatment assessed adherence with rehabilitation aids, booklet knowledge, anxiety, depression and sexual functioning/satisfaction.

RESULTS

Dilator adherence and booklet knowledge were significantly higher in the intervention group than in the control group (averaged over time points), with scores significantly increasing over time. Younger age and gynaecological cancer were significant predictors of greater dilator adherence. No significant group differences were found on psychological and sexual measures.

CONCLUSIONS

The psychosexual rehabilitation booklet was effective in educating women with gynaecological and anorectal cancers about PRT-related psychosexual side-effects and rehabilitation options, as well as promoting uptake of vaginal dilator use. Future research should elucidate the effectiveness of this booklet in women with greater psychological and sexual functioning needs.

A post-liberal theory of stratification

The iconic 'liberal theory' of stratification fails to attend to the many types of downward mobility and wage loss generated by late-industrial stratification systems. Although the liberal theory and its close cousins assume that loss and failure will be interpreted in individualistic terms, recent developments suggest instead that they are generating solidary groups that are increasingly locked into zero-sum contest and successfully mobilized by politicians and other norm entrepreneurs. These developments imply a Marxisant future for late-industrial inequality that bears scant resemblance to the highly individualized, unstructured, and non-conflictual stratification system envisaged by the liberal theory. We outline a new post-liberal theory of stratification that better captures the forces making for change and resistance in late-industrial societies.