On the Origin and Evolution of the Mosquito Male-determining Factor Nix.

The mosquito family Culicidae is divided into 2 subfamilies named the Culicinae and Anophelinae. Nix, the dominant male-determining factor, has only been found in the culicines Aedes aegypti and Aedes albopictus, 2 important arboviral vectors that belong to the subgenus Stegomyia. Here we performed sex-specific whole-genome sequencing and RNAseq of divergent mosquito species and explored additional male-inclusive datasets to investigate the distribution of Nix. Except for the Culex genus, Nix homologs were found in all species surveyed from the Culicinae subfamily, including 12 additional species from 3 highly divergent tribes comprising 4 genera, suggesting Nix originated at least 133 to 165 million years ago (MYA). Heterologous expression of 1 of 3 divergent Nix open reading frames (ORFs) in Ae. aegypti resulted in partial masculinization of genetic females as evidenced by morphology and doublesex splicing. Phylogenetic analysis suggests Nix is related to femaleless (fle), a recently described intermediate sex-determining factor found exclusively in anopheline mosquitoes. Nix from all species has a conserved structure, including 3 RNA-recognition motifs (RRMs), as does fle. However, Nix has evolved at a much faster rate than fle. The RRM3 of both Nix and fle are distantly related to the single RRM of a widely distributed and conserved splicing factor transformer-2 (tra2). The RRM3-based phylogenetic analysis suggests this domain in Nix and fle may have evolved from tra2 or a tra2-related gene in a common ancestor of mosquitoes. Our results provide insights into the evolution of sex determination in mosquitoes and will inform broad applications of mosquito-control strategies based on manipulating sex ratios toward nonbiting males.

Chronic high-sugar diet in adulthood protects Caenorhabditis elegans from 6-OHDA-induced dopaminergic neurodegeneration.

BACKGROUND: Diets high in saturated fat and sugar, termed "Western diets," have been associated with several negative health outcomes, including increased risk for neurodegenerative disease. Parkinson's disease (PD) is the second most prevalent neurodegenerative disease and is characterized by the progressive death of dopaminergic neurons in the brain. We build upon previous work characterizing the impact of high-sugar diets in Caenorhabditis elegans to mechanistically evaluate the relationship between high-sugar diets and dopaminergic neurodegeneration. RESULTS: Adult high-glucose and high-fructose diets, or exposure from day 1 to 5 of adulthood, led to increased lipid content, shorter lifespan, and decreased reproduction. However, in contrast to previous reports, we found that adult chronic high-glucose and high-fructose diets did not induce dopaminergic neurodegeneration alone and were protective from 6-hydroxydopamine (6-OHDA) induced degeneration. Neither sugar altered baseline electron transport chain function and both increased vulnerability to organism-wide ATP depletion when the electron transport chain was inhibited, arguing against energetic rescue as a basis for neuroprotection. The induction of oxidative stress by 6-OHDA is hypothesized to contribute to its pathology, and high-sugar diets prevented this increase in the soma of the dopaminergic neurons. However, we did not find increased expression of antioxidant enzymes or glutathione levels. Instead, we found evidence suggesting downregulation of the dopamine reuptake transporter dat-1 that could result in decreased 6-OHDA uptake. CONCLUSIONS: Our work uncovers a neuroprotective role for high-sugar diets, despite concomitant decreases in lifespan and reproduction. Our results support the broader finding that ATP depletion alone is insufficient to induce dopaminergic neurodegeneration, whereas increased neuronal oxidative stress may drive degeneration. Finally, our work highlights the importance of evaluating lifestyle by toxicant interactions.

Protocol: evaluation of an optimised couples-focused intervention to increase testing for HIV in rural KwaZulu-Natal, South Africa, the Igugu Lethu ('Our treasure') cohort study.

BACKGROUND: Between 2012 and 2015, the Uthando Lwethu (UL) study demonstrated that a theory-based behavioural couples-focused intervention significantly increased participation in couples HIV testing and counselling (CHTC) among South African couples who had never previously tested for HIV together or mutually disclosed their HIV status, 42% compared to 12% of the control group at 9 months follow-up. Although effective, we were nonetheless concerned that in this high prevalence setting the majority (58%) of intervention couples chose not to test together. In response we optimised the UL intervention and in a new study, 'Igugu Lethu', we are evaluating the success of the optimised intervention in promoting CHTC. METHODS: One hundred eighty heterosexual couples, who have been in a relationship together for at least 6 months, are being recruited and offered the optimised couples-focused intervention. In the Igugu Lethu study, we have expanded the health screening visit offered to couples to include other health conditions in addition to CHTC. Enrolled couples who choose to schedule CHTC will also have the opportunity to undertake a random blood glucose test, blood pressure and BMI measurements, and self-sample for STI testing as part of their health screening. Individual surveys are administered at baseline, 4 weeks and 4 months follow-up. The proportion of couples who decide to test together for HIV will be compared to the results of the intervention arm in the UL study (historical controls). To facilitate this comparison, we will use the same recruitment and follow-up strategies in the same community as the previous UL study. DISCUSSION: By strengthening communication and functioning within the relationship, the Igugu Lethu study, like the previous UL study, aims to transform the motivation of individual partners from a focus on their own health to shared health as a couple. The Igugu Lethu study findings will answer whether the optimised couples-focused behavioural intervention and offering CHTC as part of a broader health screening for couples can increase uptake of CHTC by 40%, an outcome that would be highly desirable in populations with high HIV prevalence. TRIAL REGISTRATION: Retrospectively registered. ISRCTN Registry ISRCTN 46162564 Registered on 26th May 2022.

Xenobiotic metabolism and transport in Caenorhabditis elegans.

Caenorhabditis elegans has emerged as a major model in biomedical and environmental toxicology. Numerous papers on toxicology and pharmacology in C. elegans have been published, and this species has now been adopted by investigators in academic toxicology, pharmacology, and drug discovery labs. C. elegans has also attracted the interest of governmental regulatory agencies charged with evaluating the safety of chemicals. However, a major, fundamental aspect of toxicological science remains underdeveloped in C. elegans: xenobiotic metabolism and transport processes that are critical to understanding toxicokinetics and toxicodynamics, and extrapolation to other species. The aim of this review was to initially briefly describe the history and trajectory of the use of C. elegans in toxicological and pharmacological studies. Subsequently, physical barriers to chemical uptake and the role of the worm microbiome in xenobiotic transformation were described. Then a review of what is and is not known regarding the classic Phase I, Phase II, and Phase III processes was performed. In addition, the following were discussed (1) regulation of xenobiotic metabolism; (2) review of published toxicokinetics for specific chemicals; and (3) genetic diversity of these processes in C. elegans. Finally, worm xenobiotic transport and metabolism was placed in an evolutionary context; key areas for future research highlighted; and implications for extrapolating C. elegans toxicity results to other species discussed.

Infection Control Behavior at Home During the COVID-19 Pandemic: Observational Study of a Web-Based Behavioral Intervention (Germ Defence).

BACKGROUND: To control the COVID-19 pandemic, people should adopt protective behaviors at home (self-isolation, social distancing, putting shopping and packages aside, wearing face coverings, cleaning and disinfecting, and handwashing). There is currently limited support to help individuals conduct these behaviors. OBJECTIVE: This study aims to report current household infection control behaviors in the United Kingdom and examine how they might be improved. METHODS: This was a pragmatic cross-sectional observational study of anonymous participant data from Germ Defence between May 6-24, 2020. Germ Defence is an open-access fully automated website providing behavioral advice for infection control within households. A total of 28,285 users sought advice from four website pathways based on household status (advice to protect themselves generally, to protect others if the user was showing symptoms, to protect themselves if household members were showing symptoms, and to protect a household member who is at high risk). Users reported current infection control behaviors within the home and intentions to change these behaviors. RESULTS: Current behaviors varied across all infection control measures but were between sometimes (face covering: mean 1.61, SD 1.19; social distancing: mean 2.40, SD 1.22; isolating: mean 2.78, SD 1.29; putting packages and shopping aside: mean 2.75, SD 1.55) and quite often (cleaning and disinfecting: mean 3.17, SD 1.18), except for handwashing (very often: mean 4.00, SD 1.03). Behaviors were similar regardless of the website pathway used. After using Germ Defence, users recorded intentions to improve infection control behavior across all website pathways and for all behaviors (overall average infection control score mean difference 0.30, 95% CI 0.29-0.31). CONCLUSIONS: Self-reported infection control behaviors other than handwashing are lower than is optimal for infection prevention, although handwashing is much higher. Advice using behavior change techniques in Germ Defence led to intentions to improve these behaviors. Promoting Germ Defence within national and local public health and primary care guidance could reduce COVID-19 transmission.

Current provision of general practitioner services in or alongside emergency departments in England.

BACKGROUND: In 2017, general practitioners in or alongside the emergency department (GPED), an approach that employs GPs in or alongside the ED to address increasing ED demand, was advocated by the National Health Service in England and supported by capital funding. However, little is known about the models of GPED that have been implemented. METHODS: Data were collected at two time points: September 2017 and December 2019, on the GPED model in use (if any) at 163/177 (92%) type 1 EDs in England. Models were categorised according to a taxonomy as 'inside/integrated', 'inside/parallel', 'outside/onsite' or 'outside/offsite'. Multiple data sources used included: on-line surveys, interviews, case study data and publicly available information. RESULTS: An increase of EDs using GPED was observed from 81% to 95% over the study period. 'Inside/parallel' was the most frequently used model: 30% (44/149) in 2017, rising to 49% (78/159) in 2019. The adoption of 'inside/integrated' models fell from 26% (38/149) to 9% (15/159). Capital funding was received by 87% (142/163) of the EDs sampled. We identified no significant difference between the GPED model adopted and observable characteristics of EDs of annual attendance, 4-hour wait, rurality and deprivation within the population served. CONCLUSION: The majority of EDs in England have now adopted GPED. The availability of capital funding to finance structural changes so that separate GP services can be provided may explain the rise in parallel models and the decrease in integrated models. Further research is required to understand the relative effectiveness of the various models of GPED identified.

Taxonomy of the form and function of primary care services in or alongside emergency departments: concepts paper.

Primary care services in or alongside emergency departments look and function differently and are described using inconsistent terminology. Research to determine effectiveness of these models is hampered by outdated classification systems, limiting the opportunity for data synthesis to draw conclusions and inform decision-making and policy. We used findings from a literature review, a national survey of Type 1 emergency departments in England and Wales, staff interviews, other routine data sources and discussions from two stakeholder events to inform the taxonomy. We categorised the forms inside or outside the emergency department: inside primary care services may be integrated with emergency department patient flow or may run parallel to that activity; outside services may be offered on site or off site. We then describe a conceptual spectrum of integration: identifying constructs that influence how the services function-from being closer to an emergency medicine service or to usual primary care. This taxonomy provides a basis for future evaluation of service models that will comprise the evidence base to inform policy-making in this domain. Commissioners and service providers can consider these constructs in characterising and designing services depending on local circumstances and context.

Young People's Experiences of Viewing the Fitspiration Social Media Trend: Qualitative Study.

BACKGROUND: Social media use has become ubiquitous in the lives of many people, especially young adults. A popular recent trend emerging on social media is that of posting and following 'Fitspirational' content - material that purports to motivate and showcase healthy lifestyle habits, particularly relating to exercise and diet. There is very limited existing literature on how engaging with this type of content influences people's psychological and physical heath. Initial studies have focused on concerns over potential negative effects on psychological wellbeing including body image, self-esteem and eating disorders. OBJECTIVE: We aimed to address a gap in the literature for exploratory research on this topic from the perspective of users. We used a qualitative approach to explore how people experience viewing Fitspiration on social media including why and how they engage with this material and how they perceive that it affects their thoughts, emotions, behaviour and health. METHODS: We recruited 20 young adults (14 females, 6 males, aged 18-25) who self-declared themselves to be Fitspiration followers to participate in either focus groups or individual interviews. We asked detailed, open-ended questions about their motivations for following Fitspiration, experiences of viewing this content and its perceived impact. We used inductive thematic analysis to derive themes that represented common and salient features of the data set. RESULTS: Four main themes were developed: 1) A tool with the potential to support healthy living, 2) Unrealistic, untrustworthy content, 3) Negative effects on emotional wellbeing, and 4) Vulnerability and protective factors. Following Fitspirational posts on social media can provide young people with knowledge and motivation that may support healthy lifestyle behaviours. However, a range of harms also appeared to arise from Fitspiration viewing ranging from minor annoyances and frustrations to more meaningful negative effects on psychological & physical health. These negative effects seemed to persist despite individuals acknowledging that the material can be unrealistic, and believing that they are personally equipped to minimise harms to themselves. CONCLUSIONS: This study suggests that Fitspiration on social media can be attractive and compelling for young people but appears to bring about negative as well as positive effects. Future research should aim to confirm the scale and intensity of positive and negative effects and investigate ways of harnessing desirable outcomes and minimising undesirable outcomes.

Understanding how primary care practitioners perceive an online intervention for the management of hypertension.

BACKGROUND: In order to achieve successful implementation an intervention needs to be acceptable and feasible to its users and must overcome barriers to behaviour change. The Person-Based Approach can help intervention developers to improve their interventions to ensure more successful implementation. This study provides an example of using the Person-Based Approach to refine a digital intervention for hypertension (HOME BP). METHODS: Our Person-Based Approach involved conducting qualitative focus groups with practice staff to explore their perceptions of HOME BP and to identify any potential barriers to implementation of the HOME BP procedures. We took an iterative approach moving between data collection, analysis and modifications to the HOME BP intervention, followed by further data collection. The data was analysed using thematic analysis. RESULTS: Many aspects of HOME BP appeared to be acceptable, persuasive and feasible to implement. Practitioners perceived benefits in using HOME BP, including that it could empower patients to self-manage their health, potentially overcome clinical inertia around prescribing medication and save both the patient and practitioner time. However, practitioners also had some concerns. Some practitioners were concerned about the accuracy of patients' home blood pressure readings, or the potential for home monitoring to cause patients anxiety and therefore increase consultations. Some GPs lacked confidence in choosing multiple medication changes, or had concerns about unanticipated drug interactions. A few nurses were concerned that the model of patient support they were asked to provide was not consistent with their perceived role. Modifications were made to the intervention based on this feedback, which appeared to help overcome practitioners' concerns and improve the acceptability and feasibility of the intervention. CONCLUSIONS: This paper provides a detailed example of using the Person-Based Approach to refine HOME BP, demonstrating how we improved the acceptability and feasibility of HOME BP based on feedback from practice staff. This demonstration may be useful to others developing digital interventions.

The effect of common paralytic agents used for fluorescence imaging on redox tone and ATP levels in Caenorhabditis elegans.

One aspect of Caenorhabditis elegans that makes it a highly valuable model organism is the ease of use of in vivo genetic reporters, facilitated by its transparent cuticle and highly tractable genetics. Despite the rapid advancement of these technologies, worms must be paralyzed for most imaging applications, and few investigations have characterized the impacts of common chemical anesthetic methods on the parameters measured, in particular biochemical measurements such as cellular energetics and redox tone. Using two dynamic reporters, QUEEN-2m for relative ATP levels and reduction-oxidation sensitive GFP (roGFP) for redox tone, we assess the impact of commonly used chemical paralytics. We report that no chemical anesthetic is entirely effective at doses required for full paralysis without altering redox tone or ATP levels, and that anesthetic use alters the detected outcome of rotenone exposure on relative ATP levels and redox tone. We also assess the use of cold shock, commonly used in combination with physical restraint methods, and find that cold shock does not alter either ATP levels or redox tone. In addition to informing which paralytics are most appropriate for research in these topics, we highlight the need for tailoring the use of anesthetics to different endpoints and experimental questions. Further, we reinforce the need for developing less disruptive paralytic methods for optimal imaging of dynamic in vivo reporters.

Morphological hallmarks of dopaminergic neurodegeneration are associated with altered neuron function in Caenorhabditis elegans.

Caenorhabditis elegans (C. elegans) is an excellent model system to study neurodegenerative diseases, such as Parkinson's disease, as it enables analysis of both neuron morphology and function in live animals. Multiple structural changes in neurons, such as cephalic dendrite morphological abnormalities, have been considered hallmarks of neurodegeneration in this model, but their relevance to changes in neuron function are not entirely clear. We sought to test whether hallmark morphological changes associated with chemically induced dopaminergic neuron degeneration, such as dendrite blebbing, breakage, and loss, are indicative of neuronal malfunction and result in changes in behavior. We adapted an established dopaminergic neuronal function assay by measuring paralysis in the presence of exogenous dopamine, which revealed clear differences between cat-2 dopamine deficient mutants, wildtype worms, and dat-1 dopamine abundant mutants. Next, we integrated an automated image processing algorithm and a microfluidic device to segregate worm populations by their cephalic dendrite morphologies. We show that nematodes with dopaminergic dendrite degeneration markers, such as blebbing or breakage, paralyze at higher rates in a dopamine solution, providing evidence that dopaminergic neurodegeneration morphologies are correlated with functional neuronal outputs.

The effect of common paralytic agents used for fluorescence imaging on redox tone and ATP levels in Caenorhabditis elegans.

One aspect of Caenorhabditis elegans that makes it a highly valuable model organism is the ease of use of in vivo genetic reporters, facilitated by its transparent cuticle and highly tractable genetics. Despite the rapid advancement of these technologies, worms must be paralyzed for most imaging applications, and few investigations have characterized the impacts of common chemical anesthetic methods on the parameters measured, in particular biochemical measurements such as cellular energetics and redox tone. Using two dynamic reporters, QUEEN-2m for relative ATP levels and reduction-oxidation sensitive GFP (roGFP) for redox tone, we assess the impact of commonly used chemical paralytics. We report that no chemical anesthetic is entirely effective at doses required for full paralysis without altering redox tone or ATP levels, though 100 mM 2,3-Butadione monoxime appears to be the least problematic. We also assess the use of cold shock, commonly used in combination with physical restraint methods, and find that cold shock does not alter either ATP levels or redox tone. In addition to informing which paralytics are most appropriate for research in these topics, we highlight the need for tailoring the use of anesthetics to different endpoints and experimental questions. Further, we reinforce the need for developing less disruptive paralytic methods for optimal imaging of dynamic in vivo reporters.

An unbiased, automated platform for scoring dopaminergic neurodegeneration in C. elegans.

Caenorhabditis elegans ( C. elegans ) has served as a simple model organism to study dopaminergic neurodegeneration, as it enables quantitative analysis of cellular and sub-cellular morphologies in live animals. These isogenic nematodes have a rapid life cycle and transparent body, making high-throughput imaging and evaluation of fluorescently tagged neurons possible. However, the current state-of-the-art method for quantifying dopaminergic degeneration requires researchers to manually examine images and score dendrites into groups of varying levels of neurodegeneration severity, which is time consuming, subject to bias, and limited in data sensitivity. We aim to overcome the pitfalls of manual neuron scoring by developing an automated, unbiased image processing algorithm to quantify dopaminergic neurodegeneration in C. elegans . The algorithm can be used on images acquired with different microscopy setups and only requires two inputs: a maximum projection image of the four cephalic neurons in the C. elegans head and the pixel size of the user’s camera. We validate the platform by detecting and quantifying neurodegeneration in nematodes exposed to rotenone, cold shock, and 6-hydroxydopamine using 63x epifluorescence, 63x confocal, and 40x epifluorescence microscopy, respectively. Analysis of tubby mutant worms with altered fat storage showed that, contrary to our hypothesis, increased adiposity did not sensitize to stressor-induced neurodegeneration. We further verify the accuracy of the algorithm by comparing code-generated, categorical degeneration results with manually scored dendrites of the same experiments. The platform, which detects 19 different metrics of neurodegeneration, can provide comparative insight into how each exposure affects dopaminergic neurodegeneration patterns.

An unbiased, automated platform for scoring dopaminergic neurodegeneration in C. elegans.

Caenorhabditis elegans (C. elegans) has served as a simple model organism to study dopaminergic neurodegeneration, as it enables quantitative analysis of cellular and sub-cellular morphologies in live animals. These isogenic nematodes have a rapid life cycle and transparent body, making high-throughput imaging and evaluation of fluorescently tagged neurons possible. However, the current state-of-the-art method for quantifying dopaminergic degeneration requires researchers to manually examine images and score dendrites into groups of varying levels of neurodegeneration severity, which is time consuming, subject to bias, and limited in data sensitivity. We aim to overcome the pitfalls of manual neuron scoring by developing an automated, unbiased image processing algorithm to quantify dopaminergic neurodegeneration in C. elegans. The algorithm can be used on images acquired with different microscopy setups and only requires two inputs: a maximum projection image of the four cephalic neurons in the C. elegans head and the pixel size of the user's camera. We validate the platform by detecting and quantifying neurodegeneration in nematodes exposed to rotenone, cold shock, and 6-hydroxydopamine using 63x epifluorescence, 63x confocal, and 40x epifluorescence microscopy, respectively. Analysis of tubby mutant worms with altered fat storage showed that, contrary to our hypothesis, increased adiposity did not sensitize to stressor-induced neurodegeneration. We further verify the accuracy of the algorithm by comparing code-generated, categorical degeneration results with manually scored dendrites of the same experiments. The platform, which detects 20 different metrics of neurodegeneration, can provide comparative insight into how each exposure affects dopaminergic neurodegeneration patterns.

Morphological hallmarks of dopaminergic neurodegeneration are associated with altered neuron function in Caenorhabditis elegans.

Caenorhabditis elegans (C. elegans) is an excellent model system to study neurodegenerative diseases, such as Parkinson's disease, as it enables analysis of both neuron morphology and function in live animals. Multiple structural changes in neurons, such as cephalic dendrite morphological abnormalities, have been considered hallmarks of neurodegeneration in this model, but their relevance to changes in neuron function are not entirely clear. We sought to test whether hallmark morphological changes associated with chemically induced dopaminergic neuron degeneration, such as dendrite blebbing, breakage, and loss, are indicative of neuronal malfunction and result in changes in behavior. We adapted an established dopaminergic neuronal function assay by measuring paralysis in the presence of exogenous dopamine, which revealed clear differences between cat-2 dopamine deficient mutants, wildtype worms, and dat-1 dopamine abundant mutants. Next, we integrated an automated image processing algorithm and a microfluidic device to segregate worm populations by their cephalic dendrite morphologies. We show that nematodes with dopaminergic dendrite degeneration markers, such as blebbing or breakage, paralyze at higher rates in a dopamine solution, providing evidence that dopaminergic neurodegeneration morphologies are correlated with functional neuronal outputs.

Chronic high-sugar diet in adulthood protects Caenorhabditis elegans from 6-OHDA induced dopaminergic neurodegeneration.

BACKGROUND: Diets high in saturated fat and sugar, termed western diets, have been associated with several negative health outcomes, including increased risk for neurodegenerative disease. Parkinson s Disease (PD) is the second most prevalent neurodegenerative disease and is characterized by the progressive death of dopaminergic neurons in the brain. We build upon previous work characterizing the impact of high sugar diets in Caenorhabditis elegans to mechanistically evaluate the relationship between high sugar diets and dopaminergic neurodegeneration. RESULTS: Non-developmental high glucose and fructose diets led to increased lipid content and shorter lifespan and decreased reproduction. However, in contrast to previous reports, we found that non-developmental chronic high-glucose and high-fructose diets did not induce dopaminergic neurodegeneration alone and were protective from 6-hydroxydopamine (6-OHDA) induced degeneration. Neither sugar altered baseline electron transport chain function, and both increased vulnerability to organism-wide ATP depletion when the electron transport chain was inhibited, arguing against energetic rescue as a basis for neuroprotection. The induction of oxidative stress by 6-OHDA is hypothesized to contribute to its pathology, and high sugar diets prevented this increase in the soma of the dopaminergic neurons. However, we did not find increased expression of antioxidant enzymes or glutathione levels. Instead, we found evidence suggesting alterations to dopamine transmission that could result in decreased 6-OHDA uptake. CONCLUSION: Our work uncovers a neuroprotective role for high sugar diets, despite concomitant decreases in lifespan and reproduction. Our results support the broader finding that ATP depletion alone is insufficient to induce dopaminergic neurodegeneration, whereas increased neuronal oxidative stress may drive degeneration. Finally, our work highlights the importance of evaluating lifestyle by toxicant interactions.

Increased cytotoxicity of Pb2+ with co-exposures to a mitochondrial uncoupler and mitochondrial calcium uniporter inhibitor.

Lead (Pb2+) is an important developmental toxicant. The mitochondrial calcium uniporter (MCU) imports calcium ions using the mitochondrial membrane potential (MMP), and also appears to mediate the influx of Pb2+ into the mitochondria. Since our environment contains mixtures of toxic agents, it is important to consider multi-chemical exposures. To begin to develop generalizable, predictive models of interactive toxicity, we developed mechanism-based hypotheses about interactive effects of Pb2+ with other chemicals. To test these hypotheses, we exposed HepG2 (human liver) cells to Pb2+ alone and in mixtures with other mitochondria-damaging chemicals: carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), a mitochondrial uncoupler that reduces MMP, and Ruthenium Red (RuRed), a dye that inhibits the MCU. After 24 hours, Pb2+ alone, the mixture of Pb2+ and RuRed, and the mixture of Pb2+ and FCCP caused no decrease in cell viability. However, the combination of all three exposures led to a significant decrease in cell viability at higher Pb2+ concentrations. After 48 hours, the co-exposure to elevated Pb2+ concentrations and FCCP caused a significant decrease in cell viability, and the mixture of all three showed a clear dose-response curve with significant decreases in cell viability across a range of Pb2+ concentrations. We performed ICP-MS analyses on isolated mitochondrial and cytosolic fractions and found no differences in Pb2+ uptake across exposure groups, ruling out altered cellular uptake as the mechanism for interactive toxicity. We assessed MMP following exposure and observed a decrease in membrane potential that corresponds to loss of cell viability but is likely not sufficient to be the causative mechanistic driver of cell death. This research provides a mechanistically-based framework for understanding Pb2+ toxicity in mixtures with mitochondrial toxicants.

The multi-dimensional burden of cirrhosis and hepatic encephalopathy on patients and caregivers.

OBJECTIVES: Cirrhosis and hepatic encephalopathy (HE) can adversely affect survival, but their effect on socioeconomic and emotional burden on the family is not clear. The aim was to study the emotional and socioeconomic burden of cirrhosis and HE on patients and informal caregivers. METHODS: A cross-sectional study in two transplant centers (Veterans and University) of cirrhotic patients and their informal caregivers was performed. Demographics for patient/caregivers, model-for-end-stage liver disease (MELD) score, and cirrhosis complications were recorded. Patients underwent a cognitive battery, sociodemographic, and financial questionnaires. Caregivers were given the perceived caregiver burden (PCB; maximum=155) and Zarit Burden Interview (ZBI)-Short Form (maximum=48) and questionnaires for depression, anxiety, and social support. RESULTS: A total of 104 cirrhotics (70% men, 44% previous HE, median MELD 12, 49% veterans) and their caregivers (66% women, 77% married, relationship duration 32±14 years) were included. Cirrhosis severely impacted the family unit with respect to work (only 56% employed), finances, and adherence. Those with previous HE had worse unemployment (87.5 vs. 19%, P=0.0001) and financial status (85 vs. 61%, P=0.019) and posed a higher caregiver burden; PCB (75 vs. 65, P=0.019) and ZBI (16 vs. 11, P=0.015) compared with others. Cognitive performance and MELD score were significantly correlated with employment and caregiver burden. Veterans and non-veterans were equally affected. On regression, depression score, MELD, and cognitive tests predicted both PCB and ZBI score. CONCLUSIONS: Previous HE and cognitive dysfunction are associated with worse employment, financial status, and caregiver burden. Cirrhosis-related expenses impact the family unit's daily functioning and medical adherence. A multidisciplinary approach to address this burden is required.

Quantifying Levels of Dopaminergic Neuron Morphological Alteration and Degeneration in Caenorhabditis elegans.

Dopamine neuron loss is involved in the pathology of Parkinson's Disease (PD), a highly prevalent neurodegenerative disorder affecting over 10 million people worldwide. Since many details about PD etiology remain unknown, studies investigating genetic and environmental contributors to PD are needed to discover methods of prevention, management, and treatment. Proper characterization of dopaminergic neuronal loss may be relevant not only to PD research, but to other increasingly prevalent neurodegenerative disorders. There are established genetic and chemical models of dopaminergic neurodegeneration in the Caenorhabditis elegans model system, with easy visualization of neurobiology supported by the nematodes' transparency and invariant neuronal architecture. In particular, hermaphroditic C. elegans' dopaminergic neuron morphological changes can be visualized using strains with fluorescent reporters driven by cell-specific promotors such as the dat-1 dopamine transporter gene, which is expressed exclusively in their eight dopaminergic neurons. With the capabilities of this model system and the appropriate technology, many laboratories have studied dopaminergic neurodegeneration. However, there is little consistency in the way the data is analyzed and much of the present literature uses binary scoring analyses that capture the presence of degeneration but not the full details of the progression of neuron loss. Here, we introduce a universal scoring system to assess morphological changes and degeneration in C. elegans' cephalic neuron dendrites. This seven-point scale allows for analysis across a full range of dendrite morphology, ranging from healthy neurons to complete dendrite loss, and considering morphological details including kinks, branching, blebs, and breaks. With this scoring system, researchers can quantify subtle age-related changes as well as more dramatic chemical-induced changes. Finally, we provide a practice set of images with commentary that can be used to train, calibrate, and assess the scoring consistency of researchers new to this method. This should improve within- and between- laboratory consistency, increasing rigor and reproducibility.

Optimising a couples-focused intervention to increase couples' HIV testing and counselling using the person-based approach: a qualitative study in Kwa-Zulu Natal, South Africa.

OBJECTIVES: This qualitative study explored how to optimise a couples-focused intervention to promote couples HIV testing and counselling (CHTC). SETTING: Community setting in Kwa-Zulu Natal, South Africa. PARTICIPANTS: Qualitative interviews were conducted with 20 couples who had participated in a couples-focused intervention and five staff members delivering the intervention. Partners were interviewed individually by researchers of the same gender. INTERVENTION: A couples-focused intervention comprised of two group sessions and four couples counselling sessions was previously shown to significantly increase uptake to CHTC in Kwa-Zulu Natal, South Africa. However, more than half of couples participating in the intervention still chose not to test together during follow-up. ANALYSIS: The transcripts were analysed using the table of changes from the person-based approach. Proposed optimisations were discussed with a community group to ensure the intervention was as persuasive and acceptable as possible. RESULTS: Many couples found it challenging to discuss CHTC with their partner due to an implied lack of trust. Optimisations to the intervention were identified to increase readiness to discuss CHTC, including education about serodiscordance, discussions about CHTC by peer mentors and open discussion of personal barriers to CHTC during couples' counselling sessions. Additional training for staff in open questioning techniques could help them feel more comfortable to explore couples' perceived barriers to CHTC, rather than advising couples to test. A logic model was developed to show anticipated mechanisms through which the optimised intervention would increase uptake to CHTC, including increasing knowledge, increasing positive outcome beliefs and managing negative emotions. CONCLUSIONS: In-depth qualitative research informed optimisations to a couples-focused intervention for further evaluation in South Africa to encourage uptake to CHTC. Suggestions are made for optimal methods to gain open feedback on intervention experiences where participants may be reluctant to share negative views.