The Blue Ribbon Committee II Report and Recommendations on Surgical Education and Training in the United States: 2024.

OBJECTIVE: An expert panel made recommendations to optimize surgical education and training based on the effects of contemporary challenges. BACKGROUND: The inaugural Blue Ribbon Committee (BRC I) proposed sweeping recommendations for surgical education and training in 2004. In light of those findings, a second BRC (BRC II) was convened to make recommendations to optimize surgical training considering the current landscape in medical education. METHODS: BRC II was a panel of 67 experts selected on the basis of experience and leadership in surgical education and training. It was organized into subcommittees which met virtually over the course of a year. They developed recommendations, along with the Steering Committee, based on areas of focus and then presented them to the entire BRC II. The Delphi Method was chosen to obtain consensus, defined as>80% agreement amongst the panel. Cronbach alpha was computed to assess the internal consistency of three Delphi rounds. RESULTS: Of 50 recommendations, 31 obtained consensus in the following aspects of surgical training (# consensus recommendation /# proposed): Workforce (1/5), Medical Student Education (3/8), Work Life Integration (4/6), Resident Education (5/7), Goals, Structure and Financing of Training (5/8), Education Support and Faculty Development (5/6), Research Training (7/9), and Educational Technology and Assessment (1/1). The internal consistency was good in Rounds 1 and 2 and acceptable in Round 3. CONCLUSIONS: BRC II used the Delphi approach to identify and recommend 31 priorities for surgical education in 2024. We advise establishing a multidisciplinary surgical educational group to oversee, monitor and facilitate implementation of these recommendations.

Goals, Structure and Financing of Surgical Residency Training: A Subcommittee Report of the Blue Ribbon Committee II.

OBJECTIVE: As part of the Blue Ribbon Committee II, review current goals, structure and financing of surgical training in Graduate Medical Education (GME) and recommend needed changes. SUMMARY BACKGROUND DATA: Surgical training has continually undergone major transitions with the 80-hour work week, earlier specialization (vascular, plastics and cardiovascular) and now entrustable professional activities (EPAs) as part of competency based medical education (CBME). Changes are needed to ensure the efficiencies of CBME are utilized, that stable graduate medical education funding is secured, and that support for surgeons who teach is made available. METHODS: Convened subcommittee discussions to determine needed focus for recommendations. RESULTS: Five recommendations are offered for changes to GME financing, incorporation of CBME, and support for educators, students and residents in training. CONCLUSIONS: Changes in surgical training related to CBME offer opportunity for change and innovation. Our subcommittee has laid out a potential path forward for improvements in GME funding, training structure, compensation of surgical educators, and support of students and residents in training.

Coproduction with peer support groups: A new approach to culturally responsive social services.

The disparity of access to suitable social services for people from culturally diverse backgrounds is receiving increased attention. Coproduction between service users and providers has the potential as an approach to improve the cultural responsiveness of social services. What remains unknown is how social service organizations can facilitate and support coproduction with people from culturally diverse backgrounds. This article examines how three disability support organizations in Australia worked with peer support groups run by people with disability and their families from Chinese background to improve the organizations' service provision. We collected qualitative data through observations of activities in the groups and semistructured interviews with group members and organization staff. We found that organizing peer support groups facilitated knowledge exchange between people from culturally diverse backgrounds and organizations to inform practice development. Five contributors to the knowledge exchange were as follows: (1) assigning staff responsibility for exchange and trust with the group; (2) encouraging the group to challenge practice and cultural norms; (3) identifying and supporting the capacity of peer facilitators; (4) fostering trust within the group; and (5) collaborating with other organizations. Cultural responsiveness means incorporating people's cultural preferences in support provision and addressing the negative influences of cultural norms on people.

Chronic Adaptations in the Dorsal Horn Following a Cervical Spinal Cord Injury in Primates.

Spinal cord injury (SCI) is devastating, with limited treatment options and variable outcomes. Most in vivo SCI research has focused on the acute and early post-injury periods, and the promotion of axonal growth, so little is understood about the clinically stable chronic state, axonal growth over time, and what plasticity endures. Here, we followed animals into the chronic phase following SCI, to address this gap. Male macaques received targeted deafferentation, affecting three digits of one hand, and were divided into short (4-6 months) or long-term (11-12 months) groups, based on post-injury survival times. Monkeys were assessed behaviorally, where possible, and all exhibited an initial post-injury deficit in manual dexterity, with gradual functional recovery over 2 months. We previously reported extensive sprouting of somatosensory corticospinal (S1 CST) fibers in the dorsal horn in the first five post-injury months. Here, we show that by 1 year, the S1 CST sprouting is pruned, with the terminal territory resembling control animals. This was reflected in the number of putatively "functional" synapses observed, which increased over the first 4-5 months, and then returned to baseline by 1 year. Microglia density also increased in the affected dorsal horn at 4-6 months and then decreased, but did not return to baseline by 1 year, suggesting refinement continues beyond this time. Overall, there is a long period of reorganization and consolidation of adaptive circuitry in the dorsal horn, extending well beyond the initial behavioral recovery. This provides a potential window to target therapeutic opportunities during the chronic phase.

Access to general practice for preventive health care for people who experience severe mental illness in Sydney, Australia: a qualitative study.

BACKGROUND: People with lived experience of severe mental illness (PWLE) live around 20years less than the general population. Most deaths are due to preventable health conditions. Improved access to high-quality preventive health care could help reduce this health inequity. This study aimed to answer the question: What helps PWLE access preventive care from their GP to prevent long-term physical conditions? METHODS: Qualitative interviews (n=10) and a focus group (n=10 participants) were conducted with PWLE who accessed a community mental health service and their carers (n=5). An asset-based framework was used to explore what helps participants access and engage with a GP. A conceptual framework of access to care guided data collection and analysis. Member checking was conducted with PWLE, service providers and other stakeholders. A lived experience researcher was involved in all stages of the study. RESULTS: PWLE and their carers identified multiple challenges to accessing high-quality preventive care, including the impacts of their mental illness, cognitive capacity, experiences of discrimination and low income. Some GPs facilitated access and communication. Key facilitators to access were support people and affordable preventive care. CONCLUSION: GPs can play an important role in facilitating access and communication with PWLE but need support to do so, particularly in the context of current demands in the Australian health system. Support workers, carers and mental health services are key assets in supporting PWLE and facilitating communication between PWLE and GPs. GP capacity building and system changes are needed to strengthen primary care's responsiveness to PWLE and ability to engage in collaborative/shared care.

How do Australian mental health services use easy read to make information accessible for people with intellectual disability?

INTRODUCTION: Access to health information is a right for all people. Easy read information is one strategy used to make information accessible for people with intellectual disability. This research explored how easy read is used and the ways accessible information can address access barriers, with a focus on Australian mental health services. METHODS: Semi-structured interviews were conducted across four sites to explore how easy read was used. Participants (n = 49) were easy read users, health practitioners and staff from services providing mental health care in New South Wales, Australia. An integrated health literacy framework was used to analyse data. RESULTS: Most mental health staff did not use easy read or other accessible information, and did not consistently offer people with intellectual disability opportunities to understand, appraise and apply health information. This investigation confirmed the limited availability of accessible information resources, including easy read, and the importance of relationships of support when accessing health information. CONCLUSION: People with intellectual disability did not routinely have access to mental health information. Substantial change is required to address this disparity. IMPLICATIONS: Agency policy and processes require change to support staff practices that uphold the right to information. Inclusive practices that incorporate using easy read in health contexts, including mental health, are needed to facilitate change.

Small sensory spinal lesions that affect hand function in monkeys greatly alter primary afferent and motor neuron connections in the cord.

Small sensory spinal injuries induce plasticity across the neuraxis, but little is understood about their effect on segmental connections or motor neuron (MN) function. Here, we begin to address this at two levels. First, we compared afferent input distributions from the skin and muscles of the digits with corresponding MN pools to determine their spatial relationship, in both the normal state and 4-6 months after a unilateral dorsal root/dorsal column lesion (DRL/DCL), affecting digits 1-3. Second, we looked at specific changes to MN inputs and membrane properties that likely impact functional recovery. Monkeys received a targeted unilateral DRL/DCL, and 4-6 months later, cholera toxin subunit B (CT-B) was injected bilaterally into either the distal pads of digits 1-3, or related intrinsic hand muscles, to label inputs to the cord, and corresponding MNs. In controls (unlesioned side), cutaneous and proprioceptive afferents from digits 1-3 showed different distribution patterns but similar rostrocaudal spread within the dorsal horn from C1 to T2. In contrast, MNs were distributed across just two segments (C7-8). Following the lesion, sensory inputs were significantly diminished across all 10 segments, though this did not alter MN distributions. Afferent and monoamine inputs, as well as KCC2 cotransporters, were also significantly altered on the cell membrane of CT-B labeled MNs postlesion. In contrast, inhibitory neurotransmission and perineuronal net integrity were not altered at this prechronic timepoint.  Our findings indicate that even a small sensory injury can significantly impact sensory and motor spinal neurons and provide new insight into the complex process of recovery.

Understanding attributes and characteristics of the PA leader-physician relationship.

PURPOSE: This study sought to evaluate the attributes and characteristics of physician mentors, dual-roled physician assistant (PA) leaders, and how this relationship affects PA leaders and the PA leader-physician relationship. Dual-role PA leaders may possess additional formal job titles and duties as well as having direct reports. METHOD: We surveyed PA leaders at a single large academic medical center and its associated health system. The survey instrument evaluated perceptions, attitudes, and characteristics of the PA leader and influential physician and their relationship. RESULTS: Of the 56 PA leaders surveyed, 34 responded, for a 60.7% response rate. Effective communication was the most prevalent relational characteristic ranked as most important for both PA leaders (30%) and physician mentors (36%). Additional self-identified positive attributes of the team included collaborative mindset, reliability/trustworthiness, work ethic, and delivery of patient care. Influential physician mentors may have a significant effect on PA leader job satisfaction and career advancement. CONCLUSIONS: This is a novel study of PA leaders examining perceptions, beliefs, and characteristics of the PA leader-physician relationship. PAs are integral healthcare team members and medical providers. As PAs work closely in physician-led teams, further understanding the PA leader-physician relationship could influence PA and physician professional development, career trajectory, and healthcare team outcomes.

People First, Data Second: A Humanitarian Research Framework for Fieldwork with Refugees by War Zones.

War begets crises that are among the most urgent areas requiring help from the international HCI/CSCW community; yet too few scientists address it using context-based, participatory field methods and by engaging in country and regionally based, longitudinal partnerships. Drawing on the author's ongoing eight-year engagement as a design ethnographer with UNHCR Jordan and region for the Syrian War, this paper discusses Humanitarian Research as a framework for guiding HCI/CSCW research in conflict zones with displaced persons. Based on the principle of "People First, Data Second," Humanitarian Research is explained with illustrative examples along with the nature of war and UNHCR's protection mandate, the research challenges and ethical roles of HCI scientists in conflict zones and how these roles entwine with refugee stakeholders, NGOs, country actors, and university IRBs.

Singlet Oxygen Leads to Structural Changes to Chloroplasts during their Degradation in the Arabidopsis thaliana plastid ferrochelatase two Mutant.

During stress, chloroplasts produce large amounts of reactive oxygen species (ROS). Chloroplasts also contain many nutrients, including 80% of a leaf's nitrogen supply. Therefore, to protect cells from photo-oxidative damage and to redistribute nutrients to sink tissues, chloroplasts are prime targets for degradation. Multiple chloroplast degradation pathways are induced by photo-oxidative stress or nutrient starvation, but the mechanisms by which damaged or senescing chloroplasts are identified, transported to the central vacuole and degraded are poorly defined. Here, we investigated the structures involved with degrading chloroplasts induced by the ROS singlet oxygen (1O2) in the Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant. Under mild 1O2 stress, most fc2 chloroplasts appeared normal, but had reduced starch content. A subset of chloroplasts was degrading, and some protruded into the central vacuole via 'blebbing' structures. A 3D electron microscopy analysis demonstrated that up to 35% of degrading chloroplasts contained such structures. While the location of a chloroplast within a cell did not affect the likelihood of its degradation, chloroplasts in spongy mesophyll cells were degraded at a higher rate than those in palisade mesophyll cells. To determine if degrading chloroplasts have unique structural characteristics, allowing them to be distinguished from healthy chloroplasts, we analyzed fc2 seedlings grown under different levels of photo-oxidative stress. A correlation was observed among chloroplast swelling, 1O2 signaling and the state of degradation. Finally, plastoglobule (PG) enzymes involved in chloroplast disassembly were upregulated while PGs increased their association with the thylakoid grana, implicating an interaction between 1O2-induced chloroplast degradation and senescence pathways.

Struggle for recognition, rights, and redistribution: Understanding the identity of parents of children with autism spectrum disorder in China.

Introduction: The number of children diagnosed with autism spectrum disorders (ASD) worldwide has increased rapidly in the past decade and China is no exception. Yet the identity development of Chinese parents of children with ASD is little understood. This study employed an ethics of care perspective to explore the identity of parents of children with ASD as shaped in their social-cultural context in mainland China. Methods: Qualitatively driven mixed-method design was adopted. Qualitative data about their experiences were obtained from in-depth interviews with 20 parents from 17 families of children with ASD in Beijing and participant observation of 9 participants' daily parenting experience. Results: A complex and dynamic parenting identity was revealed. With limited recognition within and external to the family, parents experienced constant challenges toward their sense of self. The parents used strategies to assert their rights as carers and develop positive self-perceptions. Yet because of the unjust distribution of care work within families and with the state, the parents retained a sense of insecurity throughout the process of parenting. The parents' sense of inferiority due to devaluing children with disabilities was accentuated by traditional Chinese cultural values about good parenting. They were intensely worried about the lack of policy for support as they and their children grew older. Discussion: The findings reinforce the need for recognition of parents' dignity, capacity, and efforts in caring.

Dying with dignity: the challenges of end-of-life care in patients with substance use disorders.

Substance use disorder is a chronic disease carrying a high risk of morbidity and mortality. We report a case of a patient on long-term opioid agonist treatment who was diagnosed with metastatic cholangiocarcinoma and was referred to palliative care services almost contemporaneously with this diagnosis. In this report, we explore the challenges posed in offering holistic care during the end of life of a patient with a history of opioid dependence. A coordinated approach by addiction medicine and palliative care teams can allow patients from this complex cohort to ultimately die with dignity.

The core autophagy machinery is not required for chloroplast singlet oxygen-mediated cell death in the Arabidopsis thaliana plastid ferrochelatase two mutant.

BACKGROUND: Chloroplasts respond to stress and changes in the environment by producing reactive oxygen species (ROS) that have specific signaling abilities. The ROS singlet oxygen (1O2) is unique in that it can signal to initiate cellular degradation including the selective degradation of damaged chloroplasts. This chloroplast quality control pathway can be monitored in the Arabidopsis thaliana mutant plastid ferrochelatase two (fc2) that conditionally accumulates chloroplast 1O2 under diurnal light cycling conditions leading to rapid chloroplast degradation and eventual cell death. The cellular machinery involved in such degradation, however, remains unknown. Recently, it was demonstrated that whole damaged chloroplasts can be transported to the central vacuole via a process requiring autophagosomes and core components of the autophagy machinery. The relationship between this process, referred to as chlorophagy, and the degradation of 1O2-stressed chloroplasts and cells has remained unexplored. RESULTS: To further understand 1O2-induced cellular degradation and determine what role autophagy may play, the expression of autophagy-related genes was monitored in 1O2-stressed fc2 seedlings and found to be induced. Although autophagosomes were present in fc2 cells, they did not associate with chloroplasts during 1O2 stress. Mutations affecting the core autophagy machinery (atg5, atg7, and atg10) were unable to suppress 1O2-induced cell death or chloroplast protrusion into the central vacuole, suggesting autophagosome formation is dispensable for such 1O2-mediated cellular degradation. However, both atg5 and atg7 led to specific defects in chloroplast ultrastructure and photosynthetic efficiencies, suggesting core autophagy machinery is involved in protecting chloroplasts from photo-oxidative damage. Finally, genes predicted to be involved in microautophagy were shown to be induced in stressed fc2 seedlings, indicating a possible role for an alternate form of autophagy in the dismantling of 1O2-damaged chloroplasts. CONCLUSIONS: Our results support the hypothesis that 1O2-dependent cell death is independent from autophagosome formation, canonical autophagy, and chlorophagy. Furthermore, autophagosome-independent microautophagy may be involved in degrading 1O2-damaged chloroplasts. At the same time, canonical autophagy may still play a role in protecting chloroplasts from 1O2-induced photo-oxidative stress. Together, this suggests chloroplast function and degradation is a complex process utilizing multiple autophagy and degradation machineries, possibly depending on the type of stress or damage incurred.

Chloroplast quality control pathways are dependent on plastid DNA synthesis and nucleotides provided by cytidine triphosphate synthase two.

Reactive oxygen species (ROS) produced in chloroplasts cause oxidative damage, but also signal to initiate chloroplast quality control pathways, cell death, and gene expression. The Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant produces the ROS singlet oxygen in chloroplasts that activates such signaling pathways, but the mechanisms are largely unknown. Here we characterize one fc2 suppressor mutation and map it to CYTIDINE TRIPHOSPHATE SYNTHASE TWO (CTPS2), which encodes one of five enzymes in Arabidopsis necessary for de novo cytoplasmic CTP (and dCTP) synthesis. The ctps2 mutation reduces chloroplast transcripts and DNA content without similarly affecting mitochondria. Chloroplast nucleic acid content and singlet oxygen signaling are restored by exogenous feeding of the dCTP precursor deoxycytidine, suggesting ctps2 blocks signaling by limiting nucleotides for chloroplast genome maintenance. An investigation of CTPS orthologs in Brassicaceae showed CTPS2 is a member of an ancient lineage distinct from CTPS3. Complementation studies confirmed this analysis; CTPS3 was unable to compensate for CTPS2 function in providing nucleotides for chloroplast DNA and signaling. Our studies link cytoplasmic nucleotide metabolism with chloroplast quality control pathways. Such a connection is achieved by a conserved clade of CTPS enzymes that provide nucleotides for chloroplast function, thereby allowing stress signaling to occur.

How can coproduction help to deliver culturally responsive disability support? A case study from Australia.

How to improve access and quality of social services to respond to cultural diversity is receiving increased attention. Yet no approach to cultural responsiveness has been widely accepted. Coproduction has been championed in many service fields for better service outcomes and has the potential to inform practices for cultural responsiveness. This study explored how coproduction can be used to deliver culturally responsive social services. We conducted a qualitative case study and examined how an Australian disability service organisation operated a programme to improve cultural responsiveness with Australian Chinese people with disability and their families. The findings suggested that coproduction enabled the organisation to identify that the people with disability and their families considered services were culturally responsive when the staff were competent and committed to person-centred services. The coproduction contributed to continuous improvement of the services and revealed the qualities that were valued by the Australian Chinese service users. This study enriches the knowledge on coproduction by demonstrating the influence of the process of coproduction on outcomes for service users and providers. The study also contributes to the knowledge on cultural responsiveness by highlighting the elements of culturally responsive services valued by the service users. Coproduction could be more widely used for service development given its capacity to identify and respond to service needs. Practical implications for culturally responsive social services are that workforce training could focus on the principles of person-centred services and skills for working effectively with people from culturally diverse backgrounds.

A Re-evaluation of Whether Non-monosynaptic Homonymous H Reflex Facilitation Tests Propriospinal Circuits.

The C3-C4 propriospinal system is an important pathway mediating movement in cats; it contributes to movements in primates (including humans), and may have a role in recovery after lesion. Validated clinical tests of this system would find many applications, therefore we sought to test whether non-monosynaptic homonymous facilitation of the forearm flexor H reflex is mediated solely via a C3-C4 propriospinal pathway. In one anesthetized macaque monkey, median nerve stimulation elicited an H reflex in the flexor carpi radialis (FCR). Median nerve conditioning stimuli at sub-threshold intensities facilitated the H reflex, for inter-stimulus intervals up to 30 ms. Successive spinal surgical hemisections were then made. C2 lesion left the homonymous facilitation intact, suggesting mediation by spinal, not supraspinal pathways. Facilitation also remained after a second lesion at C5, indicating a major role for segmental (C7-C8) rather than propriospinal (C3-C4) interneurons. In separate experiments in five healthy human subjects, a threshold tracking approach assessed changes in peripheral axon excitability after conditioning stimulation. This was found to be enhanced up to 20 ms after the conditioning stimulus, and could partly, although not completely, underlie the H reflex facilitation seen. We conclude that homonymous facilitation of the H reflex in FCR can be produced by segmental spinal mechanisms, as well as by a supranormal period of nerve excitability. Unfortunately, this straightforward test cannot therefore be used for selective assessment of propriospinal circuits.

What place is there for shared housing with individualized disability support?

BACKGROUND: Individualized funding of disability support services has implications for people's choices about when to share their home. This paper examines how people with disabilities made choices about who to live with and the factors influencing these choices. METHODS: This paper discusses data from interviews with 30 people with mostly intellectual disabilities using individualized support services, 21 interviews with family members, four interviews with service managers, and a focus group with five support workers. The data come from a large evaluation of individualized housing support programs in New South Wales, Australia. RESULTS: Only some people had the opportunity to choose whether to share and with whom. Their choices were constrained by the range of housing options and their limited experience of them, even when they had support to make choices about shared housing or living alone. In some cases, the choices reflected a conceptualization of people with disabilities as different to other citizens in their rights and expectations about their social arrangements. CONCLUSION: The results have implications for information sharing, housing stock, and the need to challenge the positioning of people with disabilities relative to other people regarding choices about where and with whom to live. Implications for rehabilitation Many people preferred not to live alone, so as to improve their economic and social circumstances, and their choice and control. The choices about shared housing that many people and their supporters made were constrained by their limited experience of housing options or their familiarity with the range of choices made by other people with disabilities. Being able to draw on the material, social, and information resources of family made a big difference to their housing choices. It raises questions for policy implementation about whether individualized support may lock some people into shared housing arrangements by failing to include housing costs in the individual package.

Extensive Cortical Convergence to Primate Reticulospinal Pathways.

Early evolution of the motor cortex included development of connections to brainstem reticulospinal neurons; these projections persist in primates. In this study, we examined the organization of corticoreticular connections in five macaque monkeys (one male) using both intracellular and extracellular recordings from reticular formation neurons, including identified reticulospinal cells. Synaptic responses to stimulation of different parts of primary motor cortex (M1) and supplementary motor area (SMA) bilaterally were assessed. Widespread short latency excitation, compatible with monosynaptic transmission over fast-conducting pathways, was observed, as well as longer latency responses likely reflecting a mixture of slower monosynaptic and oligosynaptic pathways. There was a high degree of convergence: 56% of reticulospinal cells with input from M1 received projections from M1 in both hemispheres; for SMA, the equivalent figure was even higher (70%). Of reticulospinal neurons with input from the cortex, 78% received projections from both M1 and SMA (regardless of hemisphere); 83% of reticulospinal cells with input from M1 received projections from more than one of the tested M1 sites. This convergence at the single cell level allows reticulospinal neurons to integrate information from across the motor areas of the cortex, taking account of the bilateral motor context. Reticulospinal connections are known to strengthen following damage to the corticospinal tract, such as after stroke, partially contributing to functional recovery. Extensive corticoreticular convergence provides redundancy of control, which may allow the cortex to continue to exploit this descending pathway even after damage to one area.SIGNIFICANCE STATEMENT The reticulospinal tract (RST) provides a parallel pathway for motor control in primates, alongside the more sophisticated corticospinal system. We found extensive convergent inputs to primate reticulospinal cells from primary and supplementary motor cortex bilaterally. These redundant connections could maintain transmission of voluntary commands to the spinal cord after damage (e.g., after stroke or spinal cord injury), possibly assisting recovery of function.

Roles for the chloroplast-localized pentatricopeptide repeat protein 30 and the 'mitochondrial' transcription termination factor 9 in chloroplast quality control.

Chloroplasts constantly experience photo-oxidative stress while performing photosynthesis. This is particularly true under abiotic stresses that lead to the accumulation of reactive oxygen species (ROS) which oxidize DNA, proteins and lipids. Reactive oxygen species can also act as signals to induce acclimation through chloroplast degradation, cell death and nuclear gene expression. To better understand the mechanisms behind ROS signaling from chloroplasts, we have used the Arabidopsis thaliana mutant plastid ferrochelatase two (fc2) that conditionally accumulates the ROS singlet oxygen (1 O2 ) leading to chloroplast degradation and eventually cell death. Here we have mapped mutations that suppress chloroplast degradation in the fc2 mutant and demonstrate that they affect two independent loci (PPR30 and mTERF9) encoding chloroplast proteins predicted to be involved in post-transcriptional gene expression. These mutants exhibited broadly reduced chloroplast gene expression, impaired chloroplast development and reduced chloroplast stress signaling. Levels of 1 O2 , however, could be uncoupled from chloroplast degradation, suggesting that PPR30 and mTERF9 are involved in ROS signaling pathways. In the wild-type background, ppr30 and mTERF9 mutants were also observed to be less susceptible to cell death induced by excess light stress. While broad inhibition of plastid transcription with rifampicin was also able to suppress cell death in fc2 mutants, specific reductions in plastid gene expression using other mutations was not always sufficient. Together these results suggest that plastid gene expression, or the expression of specific plastid genes by PPR30 and mTERF0, is a necessary prerequisite for chloroplasts to activate the 1 O2 signaling pathways to induce chloroplast quality control pathways and/or cell death.

Reorganization of the Primate Dorsal Horn in Response to a Deafferentation Lesion Affecting Hand Function.

The loss of sensory input following a spinal deafferentation injury can be debilitating, and this is especially true in primates when the hand is involved. Although significant recovery of function occurs, little is currently understood about the reorganization of the neuronal circuitry, particularly within the dorsal horn. This region receives primary afferent input from the periphery, and cortical input via the somatosensory subcomponent of the corticospinal tract (S1 CST), and is critically important in modulating sensory transmission, both in normal and lesioned states. To determine how dorsal horn circuitry alters to facilitate recovery post-injury, we used an established deafferentation lesion model (dorsal root/dorsal column) in male monkeys to remove sensory input from just the opposing digits (digits 1-3) of one hand. This results in a deficit in fine dexterity that recovers over several months. Electrophysiological mapping, tract tracing, and immunolabeling techniques were combined to delineate specific changes to dorsal horn input circuitry. Our main findings show that (1) there is complementary sprouting of the primary afferent and S1 CST populations into an overlapping region of the reorganizing dorsal horn; (2) S1 CST and primary afferent inputs connect in different ways within this region to facilitate sensory integration; and (3) there is a loss of larger S1 CST terminal boutons in the affected dorsal horn, but no change in the size profile of the spared/sprouted primary afferent terminal boutons post-lesion. Understanding such changes helps to inform new and targeted therapies that best promote recovery.SIGNIFICANCE STATEMENT Spinal injuries that remove sensation from the hand, can be debilitating, though functional recovery does occur. We examined changes to the neuronal circuitry of the dorsal horn in monkeys following a lesion that deafferented three digits of one hand. Little is understood about dorsal horn circuitry, despite the fact that this region loses most of its normal input after such an injury, and is clearly a major focus of reorganization. We found that both the spared primary afferents and somatosensory corticospinal efferents sprouted in an overlapping region of the dorsal horn after injury, and that larger (presumably faster) corticospinal terminals are lost, suggesting a significantly altered cortical modulation of primary afferents. Understanding this changing circuitry is important for designing targeted therapies.