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Minimally invasive lateral retroperitoneal transpsoas approach for lumbar corpectomy and fusion with posterior instrumentation.
No full textIn this video, the authors highlight the operative treatment of a 55-year-old man with chronic osteomyelitis discitis. The operation entailed a minimally invasive lateral retroperitoneal transpsoas approach for L3 and L4 corpectomies, L2-5 interbody fusion, and L2-5 minimally invasive posterior instrumentation. The operation proceeded in two stages, beginning in the lateral position with corpectomy of the L3 and L4 vertebral bodies and placement of a corpectomy cage. After closure of this access wound, the patient was turned to a prone position for the posterior element of the operation. Posterior instrumentation was placed with pedicle screws at L2 and L5. The video can be found here: https://stream.cadmore.media/r10.3171/2022.3.FOCVID2210
Development of an Interactive Global Surgery Course for Interdisciplinary Learners.
No full textIntroductionGlobal surgical care is increasingly recognized in the global health agenda and requires multidisciplinary engagement. Despite high interest among medical students, residents and other learners, many surgical faculty and health experts remain uniformed about global surgical care.MethodsWe have operated an interdisciplinary graduate-level course in Global Surgical Care based on didactics and interactive group learning. Students completed a pre- and post-course survey regarding their learning experiences and results were analyzed using the Wilcoxon signed-rank test.ResultsFourteen students completed the pre-course survey, and 11 completed the post-course survey. Eleven students (79%) were enrolled in a Master's degree program in global health, with eight students (57%) planning to attend medical school. The median ranking of surgery on the global health agenda was fifth at the beginning of the course and third at the conclusion (p = 0.11). Non-infectious disease priorities tended to stay the same or increase in rank from pre- to post-course. Infectious disease priorities tended to decrease in rank (HIV/AIDS, p = 0.07; malaria, p = 0.02; neglected infectious disease, p = 0.3). Students reported that their understanding of global health (p = 0.03), global surgery (p = 0.001) and challenges faced by the underserved (p = 0.03) improved during the course. When asked if surgery was an indispensable part of healthcare, before the course 64% of students strongly agreed, while after the course 91% of students strongly agreed (p = 0.3). Students reported that the interactive nature of the course strengthened their skills in collaborative problem-solving.ConclusionsWe describe an interdisciplinary global surgery course that integrates didactics with team-based projects. Students appeared to learn core topics and held a different view of global surgery after the course. Similar courses in global surgery can educate clinicians and other stakeholders about strategies for building healthy surgical systems worldwide
Exploring the Perceptions of Local Citizens towards the Hangzhou Trap-Neuter-Release (TNR) Program and its Outcomes
No full textThis paper highlights the issue of a large number of stray cats in China and emphasizes the need for proper intervention to prevent further problems. The Trap-Neuter-Return (TNR) program policy has been implemented in many countries to control the overpopulation of stray cats, which has proven to be effective. However, in China, the TNR program has only been implemented in a few mega-cities such as Beijing, Shanghai, Shenzhen, and others. The purpose of this paper is to investigate the perspectives of local citizens on the Hangzhou TNR program, including its necessity and results. To achieve this, surveys and qualitative interviews were conducted to capture the viewpoints of both supporters and opponents of the program. The research collected information from a diverse group of citizens to gain a comprehensive understanding of public attitudes towards the TNR program for the stray cat community. Surveys are particularly valuable in providing insights into public perceptions and support for the program. They can reveal people's knowledge and experiences with stray cats, their assessment of the effectiveness of the TNR program, their level of support for the program, and their recommendations for improving it. Interviews were also conducted with local animal protection non-governmental organizations (NGOs), hospital directors, and relevant businesspersons to gain insight into their knowledge of the TNR program. Additionally, a survey was conducted to gather data on local citizens' perceptions and attitudes toward stray cats and the TNR program. The collected data were analyzed to evaluate the effectiveness of the TNR program in reducing the number of stray cats in Hangzhou, China, while considering and improving the current dilemma
Chemical shift assignments and secondary structure prediction of the phosphorelay protein VanU from Vibrio anguillarum.
No full textVibrio anguillarum is a biofilm forming Gram-negative bacterium that survives prolonged periods in seawater and causes vibriosis in marine life. A quorum-sensing signal transduction pathway initiates biofilm formation in response to environmental stresses. The phosphotransferase protein VanU is the focal point of the quorum-sensing pathway and facilitates the regulation between independent phosphorelay systems that activate or repress biofilm formation. Here we report the (1)H, (13)C, and (15)N backbone and side chain resonance assignments and secondary structure prediction for VanU from V. anguillarum
Discrimination in Workplace, Health Care, Family Settings and Mental Health among Transgender People in Sri Lanka
No full textDespite numerous studies demonstrating high rates of discrimination and poor mental health among transgender people in Western countries, little research has been conducted on this population in Sri Lanka. As such, the primary objective of this study was to assess the prevalence of discrimination experienced by transgender people in the workplace, health care, and family settings. Additionally, we investigated the potential association between discrimination and adverse mental health outcomes, including current depression, anxiety disorders, and low self-esteem. In Galle, 100 transgender participants were recruited through snowball sampling and then completed the survey through face-to-face interviews. The survey consisted of five sections: sociodemographic information, mental health scales, and discrimination experience in the workplace, health care, and family settings. We reported the prevalence of discrimination and adverse mental health outcomes. We also estimated the prevalence ratios of current depression and anxiety disorder, which are associated with work inaccessibility and workplace discrimination, adjusting for age, education, and gender identity in separate Poisson regression models.
The study found that school harassment (67%), workplace insults (63.5%), and work inaccessibility (47.4%) were the most commonly reported types of discrimination among transgender participants. Among them, the prevalence of current depression, anxiety disorder, and low self-esteem were 44%, 38%, and 81%, respectively. Furthermore, work inaccessibility was associated with a 16% increase in the prevalence of depression. Workplace discrimination, as measured by two categories (1 or 2 types of discrimination, ≥3 types of discrimination) was associated with greater prevalence (41%-56%) of depression and anxiety (22% - 46%) than non-discrimination, although all of those associations were not statistically significant.
The high prevalence of discrimination against transgender people presented in the study highlights the urgent need for legislative changes to protect their rights. Future studies should aim to identify coping resources and develop evidence-based interventions to minimize the adverse mental health consequences of discrimination. It is expected that the researchers and transgender voluntary groups who had been involved in the study may transform the study results into meaningful real-world interventions.</p
Essays on Decision Theory and Information Economics
No full textThis dissertation consists of three chapters. Chapter one is a study in decision theory that analyzes regret and information avoidance. Chapter two is a study in information theory that characterizes the comparison of ambiguous information. Chapter three discusses a persuasion model with a constrained sender.In chapter one, we study regret and information avoidance. Empirical evidence suggests that individuals selectively avoid information, depending on a relevant past choice or lack thereof. We address these findings by studying an agent whose choice behavior can be modeled as if she trades off two conflicting effects of information. The first is a psychological cost from the regret about past choices that are revealed to be suboptimal by the information, whereas the second is the instrumental value of information for making better-informed choices in the future. The primitive of our study is the agent's preference over pairs consisting of a set of menus and an information structure. A set of menus captures a three-period decision problem. Our main axioms reflect the agent's desire to limit her options in period one and to have more flexibility in period two. We posit axioms that connect the agent's consumption choice and information choice. A subjective version of the model is examined where the agent's information choice is not observable. We show that all parameters in both versions of the model can be uniquely identified from the choice behavior.In chapter two, we study informativeness orders over ambiguous information structures. We generalize Blackwell (1951)'s informativeness order to ambiguous experiments. The ambiguity in experiments is rooted in a lack of understanding about their probabilistic content. Formally, an ambiguous experiment is modeled as a mapping from an auxiliary state space to the set of unambiguous experiments. We show that one ambiguous experiment is preferred to another by every decision maker for every decision problem if and only if they are related by a condition called prior-by-prior dominance, which states that for any first-order belief the decision maker entertains on the auxiliary state space, the expected experiment resulting from this belief for the first experiment is Blackwell more informative than that of the second. This equivalence is robust across a wide range of ambiguity preferences. Comparisons of sets of experiments evaluated using the maxmin criterion are studied as a special case and are shown to result in a weaker informativeness order called Wald-more-informative, which states that for any Blackwell experiment in the convex hull of the first set of experiments, there exists another in the convex hull of the second set that is Blackwell less informative.In chapter three, we study a Bayesian persuasion problem where the persuader's choices of signals are constrained. Specifically, we model this constraint as an alpha-constraint: Probabilities of any signal realization being sent out conditional on any state of the world are bounded by alpha and one minus alpha. Under this constraint, we extend the revelation principle style result in persuasion games by showing that considering the signal realization space to be subsets of the action space is without loss of generality. But it is possible that recommending a proper subset of all actions is uniquely optimal. This possibility contrasts the existing result that having the signal realization space equal to the action space can always be optimal. Based on the revelation principle, we give an algorithm to solve the general constrained persuasion problems. We also provide a characterization of feasible distribution over posterior beliefs for the binary-state-binary-action case, and a comparison of the alpha-constraint and other existing constraints on the signal space.</p
Molecular mechanisms underlying retinal astrocyte death during development
No full textDevelopmental cell death is essential for nervous system development, sculpting the developing tissue by controlling cell numbers. While developmental neuron death has been studied extensively, the most abundant cell type of the nervous system – the astrocyte – has often been overlooked. Our lab recently showed that astrocytes in the developing retina undergo an unusual non-apoptotic form of death that eliminates a vast proportion of the original population. Further, we found that microglia are the major effectors of astrocyte death. However, the mechanisms that induce microglia to kill astrocytes remain mysterious. It is important to understand these astrocyte death mechanisms because astrocytes play a crucial role in patterning the retinal blood vessel network. Developmental perturbations to astrocyte number have large effects on their patterning, and in turn cause severe vascular patterning defects – some of which resemble vasculopathies typical of human blinding disorders. Because death has such a major impact on astrocyte number, it presumably has an outsized impact on this critical patterning process. We therefore sought to identify the non-apoptotic mechanisms that drive astrocyte death. Previously, we showed that astrocyte numbers modulate microglial phagocytic activity – increasing this activity as astrocyte numbers rise and decreasing it as astrocyte numbers decline. This observation suggested that astrocytes themselves are the source of cues that drive their own death via recruitment of phagocytic microglia. Here we identify the membrane lipid phosphatidylserine (PtdSer) as one such astrocyte-derived “eat-me” cue. PtdSer is best known as an “eat-me” signal expressed on the surface of apoptotic cells. We show that PtdSer is also externalized on the cell surface of apparently normal astrocytes during the developmental death period. Moreover, using a genetic approach to increase cell-surface PtdSer, we show that it is sufficient to drive astrocyte death. For these studies, we used an astrocyte-specific mouse knockout of Tmem30a, an obligate subunit of the flippase enzymes that normally remove PtdSer from the cell surface. In these knockout animals, microglia are recruited to Tmem30a mutant astrocytes, engulf them, and cause a significant acceleration of cell number decline. This excess astrocyte loss has functional consequences for the development of the vasculature: The astrocytic template for angiogenesis is overly sparse, which leads to vascular patterning defects and delayed angiogenesis. Interestingly, these defects can be rescued by blocking the function of a phagocytic signaling pathway that can recognize PtdSer exposure, suggesting that the excess PtdSer exposure in the Tmem30a knockout animals is responsible for the increase in astrocyte death. Altogether our findings highlight the broad impact of dysregulated astrocyte death. Understanding how astrocyte population size is controlled will provide new insights into death mechanisms that are crucial for development not only in the retina but may also sculpt glial populations elsewhere in the central nervous system. </p
A sensory-motor decoder that transforms neural responses in extrastriate area MT into smooth pursuit eye movements.
No full textVisual motion drives smooth pursuit eye movements through a sensory-motor decoder that uses multiple parallel components and neural pathways to transform the population response in extrastriate area MT into movement. We evaluated the decoder by challenging pursuit in monkeys with reduced motion reliability created by reducing coherence of motion in patches of dots. Reduced dot coherence caused deficits in both the initiation of pursuit and steady-state tracking, revealing the paradox of steady-state eye speeds that fail to accelerate to target speed in spite of persistent image motion. We recorded neural responses to reduced dot coherence in MT and found a decoder that transforms MT population responses into eye movements. During pursuit initiation, decreased dot coherence reduces MT population response amplitude without changing the preferred speed at the peak of the population response. The successful decoder reproduces the measured eye movements by multiplication of (i) the estimate of target speed from the peak of the population response with (ii) visual-motor gain based on the amplitude of the population response. During steady-state tracking, the decoder that worked for pursuit initiation failed. It predicted eye acceleration to target speed even when monkeys' eye speeds were steady at a level well below target speed. We can account for the effect of dot coherence on steady-state eye speed if sensorymotor gain also modulates the eye velocity positive feedback that normally sustains perfect steadystate tracking. Then, poor steady-state tracking persists because of balance between deceleration caused by low positive feedback gain and acceleration driven by MT
