Effects of endogenous D-alanine synthesis and autoinhibition of Bacillus anthracis germination on in vitro and in vivo infections

Bacillus anthracis transitions from a dormant spore to a vegetative bacillus through a series of structural and biochemical changes collectively referred to as germination. The timing of germination is important during early steps in infection and may determine if B. anthracis survives or succumbs to responsive macrophages. In the current study experiments determined the contribution of endogenous D-alanine production to the efficiency and timing of B. anthracis spore germination under in vitro and in vivo conditions. Racemase-mediated production of endogenous D-alanine by B. anthracis altered the kinetics for initiation of germination over a range of spore densities and exhibited a threshold effect wherein small changes in spore number resulted in major changes in germination efficiency. This threshold effect correlated with D-alanine production, was prevented by an alanine racemase inhibitor, and required L-alanine. Interestingly, endogenous production of inhibitory levels of D-alanine was detected under experimental conditions that did not support germination and in a germination-deficient mutant of B. anthracis. Racemase-dependent production of D-alanine enhanced survival of B. anthracis during interaction with murine macrophages, suggesting a role for inhibition of germination during interaction with these cells. Finally, in vivo experiments revealed an approximately twofold decrease in the 50% lethal dose of B. anthracis spores administered in the presence of D-alanine, indicating that rates of germination may be directly influenced by the levels of this amino acid during early stages of disease.     

The development of caring in the perioperative culture: nurse leaders' perspective on the struggle to retain sight of the patient

This article focuses on Swedish nurse leaders and is aimed at achieving a more complete and differentiated understanding of what constitutes caring in the perioperative culture as well as their knowledge and responsibility for the development of caring. Interviews with open-ended questions were conducted with 10 nurse leaders, in which they described their experiences of developing perioperative caring. The interpretation process was based on Gadamer's philosophy of hermeneutics. The findings indicate that developing a perioperative caring culture is a struggle to retain sight of the patient, a process that includes the following 6 phases: (1) when the nurse leaders understood perioperative caring as a process, the nurse's and patient's shared world became obvious to them; (2) safeguarding the patient's position as a unique human being; (3) safeguarding the nurse's welfare by creating a compassionate atmosphere; (4) promoting an idea means never giving up; (5) attaching importance to being trustworthy; and (6) being involved in a dynamic interaction, comprising communion and reciprocity. The most important goal of nursing leadership is to safeguard the welfare of the suffering patient and the relationship between the nurse leader and nursing staff, based on the motive of caritas derived from the idea of humanistic caring.     

ASO Visual Abstract: Time to Surgical Treatment and Facility Characteristics as Potential Drivers of Racial Disparities in Breast Cancer Mortality: Delay,Facilities, and Breast Cancer Mortality

Annals of Surgical Oncology -     

Hypoglycemia and Dysautonomia After Bariatric Surgery: a Systematic Review and Perspective

Obesity Surgery - With the increasing performance of bariatric surgery, rare complications are becoming prevalent. We review the diagnosis and treatment of dysautonomia after bariatric surgery and...     

Matched‐cohort study comparing bioactive human split‐thickness skin allograft plus standard of care to standard of care alone in the treatment of diabetic ulcers: A retrospective analysis across 470 institutions

This retrospective, matched‐cohort study analyzed 1,556 patients with diabetic ulcers treated at 470 wound centers throughout the United States to determine the effectiveness of a cryopreserved bioactive split‐thickness skin allograft plus standard of care when compared to standard of care alone. There were 778 patients treated with the graft in the treatment cohort, who were paired with 778 patients drawn from a pool of 126,864 candidates treated with standard of care alone (controls), by using propensity matching to create nearly identical cohorts. Both cohorts received standard wound care, including surgical debridement, moist wound care, and offloading. Logistic regression analysis of healing rates according to wound size, wound location, wound duration, volume reduction, exposed deep structures, and Wagner grade was performed. Amputation rates and recidivism at 3 months, 6 months, and 1 year after wound closure were analyzed. Diabetic ulcers were 59% more likely to close in the treatment cohort compared to the control cohort (p = 0.0045). The healing rate with the graft was better than standard of care across multiple subsets, but the most significant improvement was noted in the worst wounds that had a duration of 90‐179 days prior to treatment (p = 0.0073), exposed deep structures (p = 0.036), and/or Wagner Grade 4 ulcers (p = 0.04). Furthermore, the decrease in recidivism was statistically significant at 3 months, 6 months, and 1 year, with and without initially exposed deep structures (p < 0.05). The amputation rate in the treatment cohort was 41.7% less than that of the control cohort at 20 weeks (0.9% vs. 1.5%, respectively). This study demonstrated that diabetic ulcers treated with a cryopreserved bioactive split‐thickness skin allograft were more likely to heal and remain closed compared to ulcers treated with standard of care alone.