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"McKenzie, K."
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Masculinity, Social Connectedness, and Mental Health: Men’s Diverse Patterns of Practice
by
McKenzie, Sarah K.
,
Jenkin, Gabrielle
,
Collings, Sunny
in
Adult
,
Attitude to Health
,
Health Behavior
2018
Men’s mental health has remained undertheorized, particularly in terms of the gendered nature of men’s social relations. While the importance of social connections and strong supportive networks for improving mental health and well-being is well documented, we know little about men’s social support networks or how men go about seeking or mobilizing social support. An in-depth understanding of the gendered nature of men’s social connections and the ways in which the interplay between masculinity and men’s social connections can impact men’s mental health is needed. Fifteen life history interviews were undertaken with men in the community. A theoretical framework of gender relations was used to analyze the men’s interviews. The findings provide rich insights into men’s diverse patterns of practice in regards to seeking or mobilizing social support. While some men differentiated between their social connections with men and women, others experienced difficulties in mobilizing support from existing connections. Some men maintained a desire to be independent, rejecting the need for social support, whereas others established support networks from which they could actively seek support. Overall, the findings suggest that patterns of social connectedness among men are diverse, challenging the social science literature that frames all men’s social relationships as being largely instrumental, and men as less able and less interested than women in building emotional and supportive relationships with others. The implications of these findings for promoting men’s social connectedness and mental health are discussed.
Journal Article
The association between cannabis use and depression: a systematic review and meta-analysis of longitudinal studies
by
Lev-Ran, S.
,
McKenzie, K.
,
Rehm, J.
in
Adult and adolescent clinical studies
,
Biological and medical sciences
,
Cannabis
2014
Longitudinal studies reporting the association between cannabis use and developing depression provide mixed results. The objective of this study was to establish the extent to which different patterns of use of cannabis are associated with the development of depression using meta-analysis of longitudinal studies.
Peer-reviewed publications reporting the risk of developing depression in cannabis users were located using searches of EMBASE, Medline, PsychINFO and ISI Web of Science. Only longitudinal studies that controlled for depression at baseline were included. Data on several study characteristics, including measures of cannabis use, measures of depression and control variables, were extracted. Odds ratios (ORs) were extracted by age and length of follow-up.
After screening for 4764 articles, 57 articles were selected for full-text review, of which 14 were included in the quantitative analysis (total number of subjects = 76058). The OR for cannabis users developing depression compared with controls was 1.17 [95% confidence interval (CI) 1.05-1.30]. The OR for heavy cannabis users developing depression was 1.62 (95% CI 1.21-2.16), compared with non-users or light users. Meta-regression revealed no significant differences in effect based on age of subjects and marginal difference in effect based on length of follow-up in the individual studies. There was large heterogeneity in the number and type of control variables in the different studies.
Cannabis use, and particularly heavy cannabis use, may be associated with an increased risk for developing depressive disorders. There is need for further longitudinal exploration of the association between cannabis use and developing depression, particularly taking into account cumulative exposure to cannabis and potentially significant confounding factors.
Journal Article
Suicide and self-harm content on Instagram: A systematic scoping review
by
McKenzie, Sarah K.
,
Picardo, Jacobo
,
Jenkin, Gabrielle
in
Artificial intelligence
,
Biology and Life Sciences
,
Computer and Information Sciences
2020
Given concerns about suicide or self-harm content on Instagram, we conducted a systematic scoping review of peer-reviewed English language primary studies published between 2010-2019. Only ten studies had been published. Looking into purposive samples of Instagram posts tagged with self-harm related hashtags, studies report finding self-harm or suicide content in between 9-66% of their studied posts. Studies assessing Instagram's efforts to tackle such content found they had not been very effective. Despite heterogeneity in study aims, use of terminology, samples, methods of analysis, and study outcomes, we aggregated and distinguished 'content studies' and 'user studies'. Most studies showed concern for self-harm risk, but only one examined the relationship between self-harm posts and actual self-harm behaviours offline. It found such content had negative emotional effects on some users and reported preliminary evidence of potential harmful effects in relation to self-harm related behaviours offline, although causal effects cannot be claimed. At the same time, some benefits for those who engage with self-harm content online have been suggested. More research directly interviewing Instagram users to understand this phenomenon from their perspective is required. Finally, some ethical issues are discussed.
Journal Article
Urease is an essential component of the acid response network of Staphylococcus aureus and is required for a persistent murine kidney infection
2019
Staphylococcus aureus causes acute and chronic infections resulting in significant morbidity. Urease, an enzyme that generates NH3 and CO2 from urea, is key to pH homeostasis in bacterial pathogens under acidic stress and nitrogen limitation. However, the function of urease in S. aureus niche colonization and nitrogen metabolism has not been extensively studied. We discovered that urease is essential for pH homeostasis and viability in urea-rich environments under weak acid stress. The regulation of urease transcription by CcpA, Agr, and CodY was identified in this study, implying a complex network that controls urease expression in response to changes in metabolic flux. In addition, it was determined that the endogenous urea derived from arginine is not a significant contributor to the intracellular nitrogen pool in non-acidic conditions. Furthermore, we found that during a murine chronic renal infection, urease facilitates S. aureus persistence by promoting bacterial fitness in the low-pH, urea-rich kidney. Overall, our study establishes that urease in S. aureus is not only a primary component of the acid response network but also an important factor required for persistent murine renal infections.
Journal Article
Men’s Experiences of Mental Illness Stigma Across the Lifespan: A Scoping Review
2022
The stigma of men’s mental illness has been described as having wide-reaching and profound consequences beyond the condition[s] itself. Stigma negatively impacts men’s mental health help-seeking and the use of services amid impeding disclosures, diminishing social connection and amplifying economic hardship. Although men often face barriers to discussing their struggles with, and help-seeking for mental illness challenges, research focused on men’s lived experiences of mental illness stigma is, at best, emergent. This scoping review explores men’s mental illness related stigmas synthesizing and discussing the findings drawn from 21 published qualitative articles over the last 10 years. Four thematic findings were derived: (a) the weight of societal stigma, (b) stigma in male-dominated environments, (c) inequity driven stigmas, and (d) de-stigmatizing strategies. Despite evidence that stigma is a common experience for men experiencing diverse mental illness challenges, the field remains underdeveloped. Based on the scoping review findings, research gaps and opportunities for advancing the field are discussed.
Journal Article
Social regulation of insulin signaling and the evolution of eusociality in ants
2018
In eusocial insects, the vast majority of individuals sacrifice their reproductive potential to support the reproductive queen. Although this system has evolved repeatedly, there is still much debate surrounding its origin. Working with seven different species of ants, Chandra et al. used a transcriptomic approach to show that a single gene is consistently up-regulated in queens. This gene seems to confer reproductive status through integration with increased nutrition. In a clonal ant, larval signals disrupt this gene up-regulation, destabilizing the division of reproductive labor. Increasing levels of the associated peptide override these larval signals and establish eusociality. Science , this issue p. 398 Insulin signaling in the brain regulates ant community structure and behavior. Queens and workers of eusocial Hymenoptera are considered homologous to the reproductive and brood care phases of an ancestral subsocial life cycle. However, the molecular mechanisms underlying the evolution of reproductive division of labor remain obscure. Using a brain transcriptomics screen, we identified a single gene, insulin-like peptide 2 ( ilp2 ), which is always up-regulated in ant reproductives, likely because they are better nourished than their nonreproductive nestmates. In clonal raider ants ( Ooceraea biroi ), larval signals inhibit adult reproduction by suppressing ilp2 , thus producing a colony reproductive cycle reminiscent of ancestral subsociality. However, increasing ILP2 peptide levels overrides larval suppression, thereby breaking the colony cycle and inducing a stable division of labor. These findings suggest a simple model for the origin of ant eusociality via nutritionally determined reproductive asymmetries potentially amplified by larval signals.
Journal Article
Transcriptomics and neuroanatomy of the clonal raider ant implicate an expanded clade of odorant receptors in chemical communication
by
Ruta, Vanessa
,
Kronauer, Daniel J. C.
,
McKenzie, Sean K.
in
Animal Communication
,
Animals
,
Ants - anatomy & histology
2016
A major aim of sociogenomic research is to uncover common principles in the molecular evolution of sociality. This endeavor has been hampered by the small number of specific genes currently known to function in social behavior. Here we provide several lines of evidence suggesting that ants have evolved a large and novel clade of odorant receptor (OR) genes to perceive hydrocarbonbased pheromones, arguably the most important signals in ant communication. This genomic expansion is also mirrored in the ant brain via a corresponding expansion of a specific cluster of glomeruli in the antennal lobe. We show that in the clonal raider ant, hydrocarbon-sensitive basiconic sensilla are found only on the ventral surface of the female antennal club. Correspondingly, nearly all genes in a clade of 180 ORs within the 9-exon subfamily of ORs are expressed exclusively in females and are highly enriched in expression in the ventral half of the antennal club. Furthermore, we found that across species and sexes, the number of 9-exon ORs expressed in antennae is tightly correlated with the number of glomeruli in the antennal lobe region innervated by odorant receptor neurons from basiconic sensilla. Evolutionary analyses show that this clade underwent a striking gene expansion in the ancestors of all ants and slower but continued expansion in extant ant lineages. This evidence suggests that ants have evolved a large clade of genes to support pheromone perception and that gene duplications have played an important role in the molecular evolution of ant communication.
Journal Article
Empathic Accuracy and Cognitive and Affective Empathy in Young Adults With and Without Autism Spectrum Disorder
2022
This study investigated whether young adults with ASD (n = 29) had impairments in Cognitive Empathy (CE), Affective Empathy (AE) or Empathic Accuracy (EA; the ability to track changes in others’ thoughts and feelings) compared to typically-developing individuals (n = 31) using the Empathic Accuracy Task (EAT), which involves watching narrators recollecting emotionally-charged autobiographical events. Participants provided continuous ratings of the narrators’ emotional intensity (indexing EA), labelled the emotions displayed (CE) and reported whether they shared the depicted emotions (AE). The ASD group showed deficits in EA for anger but did not differ from typically-developing participants in CE or AE on the EAT. The ASD group also reported lower CE (Perspective Taking) and AE (Empathic Concern) on the Interpersonal Reactivity Index, a self-report questionnaire.
Journal Article
Proline transporters ProT and PutP are required for Staphylococcus aureus infection
2023
Proline acquired via specific transporters can serve as a proteinogenic substrate, carbon and nitrogen source, or osmolyte. Previous reports have documented that
Staphylococcus aureus
, a major community and nosocomial pathogen, encodes at least four proline transporters, PutP, OpuC, OpuD, and ProP. A combination of genetic approaches and
3
H-proline transport assays reveal that a previously unrecognized transporter, ProT, in addition to PutP, are the major proline transporters in
S
.
aureus
. Complementation experiments using constitutively expressed non-cognate promoters found that proline transport via OpuD, OpuC, and ProP is minimal. Both proline biosynthesis from arginine and proline transport via ProT are critical for growth when
S
.
aureus
is grown under conditions of high salinity. Further, proline transport mediated by ProT or PutP are required for growth in media with and without glucose, indicating both transporters function to acquire proline for proteinogenic purposes in addition to acquisition of proline as a carbon/nitrogen source. Lastly, inactivation of
proT
and
putP
resulted in a significant reduction (5 log
10
) of bacterial burden in murine skin-and-soft tissue infection and bacteremia models, suggesting that proline transport is required to establish a
S
.
aureus
infection.
Journal Article
mSphere of Influence: Metabolic redundancies enhance pathogenesis
2024
McKenzie Lehman works in the field of bacterial pathogenesis and metabolism. In this mSphere of Influence article, she reflects on how three papers entitled \"Glycolytic dependency of high-level nitric oxide resistance and virulence in
by N. P. Vitko, N. A. Spahich, and A. R. Richardson (mBio 6:e00045-15, 2015, https://doi.org/10.1128/mbio.00045-15), \"The
cystine transporters TcyABC and TcyP facilitate nutrient sulfur acquisition during infection\" by J. M. Lensmire, J. P. Dodson, B. Y. Hsueh, M. R. Wischer, et al. (Infect Immun 88:e00690-19, 2020, https://doi.org/10.1128/iai.00690-19), and \"The second messenger c-di-AMP inhibits the osmolyte uptake system OpuC in
\" by C. F. Schuster, L. E. Bellows, T. Tosi, I. Campeotto, et al. (Sci Signal 16:ra81, 2016, https://doi.org/10.1126/scisignal.aaf7279) impacted her work on bacterial metabolism and pathogenesis.
Journal Article