Anesthetic Implications of Previously Undiagnosed Temporomandibular Joint Ankylosis: A Case Report.

Temporomandibular joint (TMJ) ankylosis is characterized by bony fusion that limits TMJ mobility. We present the case of an elderly woman who was brought to the operating room for dental rehabilitation under general anesthesia. The patient had an undiagnosed TMJ ankylosis, which was discovered only after induction of anesthesia due to her nonverbal status and advanced dementia. The surgical team canceled the case due to limited access to the surgical field. We discuss the factors that suggest TMJ ankylosis and propose the perioperative management when TMJ ankylosis is suspected but unconfirmed.

Left ventricular filling pressure in Tetralogy of Fallot: Correlation between invasive and noninvasive indices.

BACKGROUND: Left heart filling pressures, as measured by pulmonary artery wedge pressure (PAWP), is associated with heart failure related mortality. Because of the prognostic importance of PAWP, several echocardiographic indices have been proposed for noninvasive assessment of PAWP. However, these indices have not been validated in the congenital heart disease population. The purpose of this study was to determine the correlation between echocardiographic indices of PAWP, and the effect of high PAWP on transplant-free survival in adults with tetralogy of Fallot (TOF). METHODS: Retrospective study of adult TOF patients that underwent cardiac catheterization at Mayo Clinic, 1990-2017. We selected these pre-defined set of echocardiographic indices of LV diastolic function: mitral valve early velocity (E), mitral valve early and late velocity ratio (E/A), mitral valve deceleration time (DT), mitral annular tissue Doppler early velocity (e'), and left atrial volume index (LAVI). RESULTS: Of the echocardiographic indices analyzed among 213 patients (age 37 ± 14 years), only E velocity (ß = 5.83, standard error = 1.52, p < 0.001) and LAVI (ß = 0.14, standard error = 0.05, p = 0.007) correlated with PAWP. LAVI > 28 ml/m2 had sensitivity of 79% and specificity of 63% (AUC 0.712), and E velocity > 1.0 m/s had sensitivity of 66% and specificity of 89% (AUC 0.692), for detecting PAWP > 15 mmHg. LAVI > 28 ml/m2 was associated with reduced 10-year transplant-free survival (49% vs 90%, p < 0.001). CONCLUSION: This study supports the use of LAVI for noninvasive assessment of PAWP and for prognostication. Further studies are required to validate these results in a different population.

Assessment and Implications of Right Ventricular Afterload in Tetralogy of Fallot.

Patients with tetralogy of Fallot (TOF) have abnormal right ventricular (RV) afterload because of residual or recurrent outflow tract obstruction, often with abnormal pulmonary artery (PA) vascular function. The purpose of this study was to determine if RV afterload was independently associated with death and/or heart transplant in patients with TOF. This is a retrospective study of TOF patients that underwent cardiac catheterization for clinical indications at Mayo clinic between 1990 and 2015. Invasively measured RV systolic pressure (RVSP) was used to define RV afterload. To explore clinical utility for echocardiographic estimates of invasive data, correlations between invasive and Doppler-derived indices of RV afterload were examined. Among 266 patients with TOF (age 35 ± 14 years, TOF-pulmonary atresia 117 [44%]), RVSP was 72 ± 28 mm Hg, PA systolic pressure 45 ± 19 mm Hg, mean PA pressure 27 ± 10 mm Hg, pulmonary vascular resistance 4.2 ± 3.1 WU, and PA wedge pressure 14 ± 5 mm Hg. Over a mean follow up of 12.9 years, there were 35 deaths and 4 heart transplants. Invasively measured RVSP (hazard ratio 1.25, 95% confidence interval 1.12 to 1.37; p <0.001) and TOF-pulmonary atresia (hazard ratio 1.18, 95% confidence interval 1.08 to 1.41; p = 0.023) were independent risk factors for death and/or transplant. Doppler-derived RVSP was well-correlated with invasive RVSP (r = 0.92, p <0.001), and was also independently associated with the combined end point. RVSP, a composite measure of RV afterload, is independently prognostic in patients with TOF, and can be reliably assessed using Doppler echocardiography. Further study is required to test whether interventions to reduce RVSP can improve outcomes in patients with TOF.

Counterbalancing Regulation in Response Memory of a Positively Autoregulated Two-Component System.

Fluctuations in nutrient availability often result in recurrent exposures to the same stimulus conditions. The ability to memorize the past event and use the "memory" to make adjustments to current behaviors can lead to a more efficient adaptation to the recurring stimulus. A short-term phenotypic memory can be conferred via carryover of the response proteins to facilitate the recurrent response, but the additional accumulation of response proteins can lead to a deviation from response homeostasis. We used the Escherichia coli PhoB/PhoR two-component system (TCS) as a model system to study how cells cope with the recurrence of environmental phosphate (Pi) starvation conditions. We discovered that "memory" of prior Pi starvation can exert distinct effects through two regulatory pathways, the TCS signaling pathway and the stress response pathway. Although carryover of TCS proteins can lead to higher initial levels of transcription factor PhoB and a faster initial response in prestarved cells than in cells not starved, the response enhancement can be overcome by an earlier and greater repression of promoter activity in prestarved cells due to the memory of the stress response. The repression counterbalances the carryover of the response proteins, leading to a homeostatic response whether or not cells are prestimulated. A computational model based on sigma factor competition was developed to understand the memory of stress response and to predict the homeostasis of other PhoB-regulated response proteins. Our insight into the history-dependent PhoBR response may provide a general understanding of how TCSs respond to recurring stimuli and adapt to fluctuating environmental conditions.IMPORTANCE Bacterial cells in their natural environments experience scenarios that are far more complex than are typically replicated in laboratory experiments. The architectures of signaling systems and the integration of multiple adaptive pathways have evolved to deal with such complexity. In this study, we examined the molecular "memory" that is generated by previous exposure to stimulus. Under our experimental conditions, activating effects of autoregulated two-component signaling and inhibitory effects of the stress response counterbalanced the transcriptional output to approach response homeostasis whether or not cells had been preexposed to stimulus. Modeling allows prediction of response behavior in different scenarios and demonstrates both the robustness of the system output and its sensitivity to historical parameters such as timing and levels of exposure to stimuli.