A myzozoan-specific protein is an essential membrane-anchoring component of the succinate dehydrogenase complex in Toxoplasma parasites.

Succinate dehydrogenase (SDH) is a protein complex that functions in the tricarboxylic acid cycle and the electron transport chain of mitochondria. In most eukaryotes, SDH is highly conserved and comprises the following four subunits: SdhA and SdhB form the catalytic core of the complex, while SdhC and SdhD anchor the complex in the membrane. Toxoplasma gondii is an apicomplexan parasite that infects one-third of humans worldwide. The genome of T. gondii encodes homologues of the catalytic subunits SdhA and SdhB, although the physiological role of the SDH complex in the parasite and the identity of the membrane-anchoring subunits are poorly understood. Here, we show that the SDH complex contributes to optimal proliferation and O2 consumption in the disease-causing tachyzoite stage of the T. gondii life cycle. We characterize a small membrane-bound subunit of the SDH complex called mitochondrial protein ookinete developmental defect (MPODD), which is conserved among myzozoans, a phylogenetic grouping that incorporates apicomplexan parasites and their closest free-living relatives. We demonstrate that TgMPODD is essential for SDH activity and plays a key role in attaching the TgSdhA and TgSdhB proteins to the membrane anchor of the complex. Our findings highlight a unique and important feature of mitochondrial energy metabolism in apicomplexan parasites and their relatives.

Experience, exposure, and attitudes regarding off-pump coronary artery bypass grafting techniques in US cardiothoracic surgical residents: Results of a survey.

Background: We sought to determine the current level of exposure to and interest in off-pump coronary artery bypass and beating heart surgery techniques regarding cardiothoracic surgical residents in the United States. Methods: An email survey consisting of 6 questions was sent to all cardiothoracic surgery residents of approved cardiothoracic training programs in the United States. The survey was emailed using the Qualtrics XM cloud-based survey platform. When the email responses were received, the answers to the survey questions were tabulated by the Qualtrics software and the resident's institution and year of graduation from their residency was noted. Results: Of 400 surveys sent, we received 99 responses for a response rate of 25%. A total of 78% of cardiothoracic surgery residents reported that they are at programs that do off-pump coronary artery bypass or beating heart surgery infrequently, noting that these cases are done in less than 5% of the coronary artery bypass graftings to which they are exposed. A total of 51% responded that they do not feel comfortable with off-pump coronary artery bypass grafting under any circumstances. A total of 49% reported some comfort with the technique with most of these respondents noting that they would do off-pump coronary artery bypass or beating heart surgery on a selective basis if the clinical situation arose and 4% plan to do off-pump coronary artery bypass routinely. Exposure to off-pump coronary artery bypass and beating heart surgery significantly correlated with future adoption of the technique by the cardiothoracic surgery residents. Cardiothoracic surgery residents in the lowest, middle, and highest terciles of exposure to off-pump coronary artery bypass and beating heart surgery plan to use these techniques 31%, 86%, and 75%, respectively, in selective cases when they are in independent practice. Conclusions: Over half of graduating cardiothoracic surgery residents do not feel comfortable with off-pump coronary artery bypass or beating heart surgery techniques. Exposure to these techniques in training correlates with comfort level and plans to use them in independent practice.

Evaluation of deep learning-based artificial intelligence techniques for breast cancer detection on mammograms: Results from a retrospective study using a BreastScreen Victoria dataset.

INTRODUCTION: This study aims to evaluate deep learning (DL)-based artificial intelligence (AI) techniques for detecting the presence of breast cancer on a digital mammogram image. METHODS: We evaluated several DL-based AI techniques that employ different approaches and backbone DL models and tested the effect on performance of using different data-processing strategies on a set of digital mammographic images with annotations of pathologically proven breast cancer. RESULTS: Our evaluation uses the area under curve (AUC) and accuracy (ACC) for performance measurement. The best evaluation result, based on 349 test cases (930 test images), was an AUC of 0.8979 [95% confidence interval (CI) 0.873, 0.923] and ACC of 0.8178 [95% CI 0.785, 0.850]. This was achieved by an AI technique that utilises a certain family of DL models, namely ResNet, as its backbone, combines the global features extracted from the whole mammogram and the local features extracted from the automatically detected cancer and non-cancer local regions in the whole image, and leverages background cropping and text removal, contrast adjustment and more training data. CONCLUSION: DL-based AI techniques have shown promising results in retrospective studies for many medical image analysis applications. Our study demonstrates a significant opportunity to boost the performance of such techniques applied to breast cancer detection by exploring different types of approaches, backbone DL models and data-processing strategies. The promising results we have obtained suggest further development of AI reading services could transform breast cancer screening in the future.

Risk-to-Benefit Relationship of Contralateral Prophylactic Mastectomy: The Argument for Bilateral Mastectomies with Immediate Reconstruction.

BACKGROUND: The increasing trend of women with unilateral breast cancer to electively undergo contralateral prophylactic mastectomy in addition to treatment of the index breast has been controversial. The authors set out to better frame the risks and benefits of contralateral prophylactic mastectomy in the treatment of unilateral breast cancer by evaluating outcomes of a large, consecutive cohort of patients. METHODS: An institutional review board-approved review of a single-surgeon (N.T.) experience (2013 to 2018) was conducted of all consecutive patients with unilateral breast cancer treated with mastectomy and immediate reconstruction. Patient characteristics, surgical pathologic results, and 30-day complications were assessed. Outcomes of patients with unilateral cancer who underwent unilateral mastectomy versus bilateral mastectomy (with one breast being contralateral prophylactic mastectomy) were compared. Logistic regression models evaluated various risk factors for potential associations with positive pathologic findings in the contralateral prophylactic mastectomy specimen and/or postoperative complications. RESULTS: Of 244 patients, 68 (27.9 percent) underwent unilateral mastectomy and 176 (72.1 percent) underwent contralateral prophylactic mastectomy. Surgical pathologic results of the prophylactic breast revealed occult ductal carcinoma in situ or invasive cancer in 13 patients (7.3 percent) and lobular carcinoma in situ in eight patients (4.6 percent). Incidence of complications was similar between groups [unilateral mastectomy, 19.12 percent (n = 13); contralateral prophylactic mastectomy, 13.07 percent (n = 23); p = 0.234]. CONCLUSIONS: Immediate reconstruction for unilateral mastectomy and contralateral prophylactic mastectomy have similar complication risk profiles, among patients as a whole and between individual breasts. These findings contribute to our understanding of the clinical impact prophylactic mastectomy and reconstruction may have on optimizing the counseling among extirpative surgeons, reconstructive surgeons, and patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Three-dimensional echocardiography of mechanical circulatory support devices.

Two-dimensional echocardiography is a crucial component for assessing the position and function of mechanical circulatory support devices, but three-dimensional echocardiography provides additional information to aid in management and may improve accuracy in the assessment of these devices. In this article, we review the utility of three-dimensional echocardiography of various mechanical circulatory support devices.