Acutely presenting congenital chest lesions: a primer for the radiologist.

Congenital chest lesions encompass several important entities. Without prompt intervention, many of these can culminate in serious complications. Timely and accurate radiologic interpretation of these entities is integral to patient management. Imaging can help characterize and prognosticate several of these entities, and may both suggest the need for and guide therapy. We overview the clinical presentation, associated complications, imaging characteristics, and prognostic indicators-both postnatal and antenatal-of the spectrum of emergently presenting congenital chest lesions. We also outline current and evolving management strategies, whether fetal, peripartum, or postnatal. The ultimate goal is to help radiologists formulate timely and effective diagnoses of these entities and boost the relevance of their input towards clinical decision-making.

Role of Rituximab in miraculous cessation of ventricular tachycardia in Granulomatosis with polyangiitis: A case report.

Granulomatosis with polyangiitis (GPA) is a rare systemic disorder of unknown aetiology. The histological findings comprise necrotising granulomatous inflammation of small arteries, arterioles, and the capillaries mainly of upper and lower respiratory tract and the kidneys. However, the disease rarely involves the cardiovascular system but may manifest as pericarditis, myocarditis, coronary arteritis, valvular lesions, and severe conduction disorders. We present an interesting, unusual, and complex case of a middle-aged man who initially presented with symptoms suggestive of Wagener's granulomatosis but two years later developed malignant ventricular arrhythmias. A diagnosis of exclusive involvement of the cardiac conduction system, without overt myocarditis, was made only after ruling it out by cardiac MRI, cardiac enzymes, echo, and normal serological markers. Evidence was paired with the cessation of monomorphic ventricular tachycardia due to induction therapy with Rituximab. In this case report, we highlight one of the rarest manifestations of GPA, i.e. Ventricular tachycardia without myocarditis.

Nonlinear postural control paradigm for larger perturbations in the presence of neural delays.

Maintaining balance is an essential skill regulated by the central nervous system (CNS) that helps humans to function effectively. Developing a physiologically motivated computational model of a neural controller with good performance is a central component for a large range of potential applications, such as the development of therapeutic and assistive devices, diagnosis of balance disorders, and designing robotic control systems. In this paper, we characterize the biomechanics of postural control system by considering the musculoskeletal dynamics in the sagittal plane, proprioceptive feedback, and a neural controller. The model includes several physiological structures, such as the feedforward and feedback mechanism, sensory noise, and proprioceptive feedback delays. A high-gain observer (HGO)-based feedback linearization controller represents the CNS analog in the modeling paradigm. The HGO gives an estimation of delayed states and the feedback linearization control law generates the feedback torques at joints to execute postural recovery movements. The whole scheme is simulated in MATLAB/Simulink. The simulation results show that our proposed scheme is robust against larger perturbations, sensory noises, feedback delays and retains a strong disturbance rejection and trajectory tracking capability. Overall, these results demonstrate that the nonlinear system dynamics, the feedforward and feedback mechanism, and physiological latencies play a key role in shaping the motor control process.

Post Dural Puncture Subdural Hematoma: A Rare Iatrogenic Complication of Neuraxial Anesthesia.

Although post-dural puncture headache is a well-known complication of neuraxial anesthesia, subdural hematoma following epidural injection is a rare but potentially under-recognized complication. The following is the case of a young female patient with no significant past medical history who developed a persistent and severe headache following the introduction of epidural anesthesia for labor induction. Imaging demonstrated multiple small subdural hematomas with findings concerning intracranial hypotension. She eventually underwent a blood patch and reported immediate relief from her headache.

High-gain observer-based nonlinear control scheme for biomechanical sit to stand movement in the presence of sensory feedback delays.

Sit-to-stand movement (STS) is a mundane activity, controlled by the central-nervous-system (CNS) via a complex neurophysiological mechanism that involves coordination of limbs for successful execution. Detailed analysis and accurate simulations of STS task have significant importance in clinical intervention, rehabilitation process, and better design for assistive devices. The CNS controls STS motion by taking inputs from proprioceptors. These input signals suffer delay in transmission to CNS making movement control and coordination more complex which may lead to larger body exertion or instability. This paper deals with the problem of STS movement execution in the presence of proprioceptive feedback delays in joint position and velocity. We present a high-gain observer (HGO) based feedback linearization control technique to mimic the CNS in controlling the STS transfer. The HGO estimates immeasurable delayed states to generate input signals for feedback. The feedback linearization output control law generates the passive torques at joints to execute the STS movement. The H2 dynamic controller calculates the optimal linear gains by using physiological variables. The whole scheme is simulated in MATLAB/Simulink. The simulations illustrate physiologically improved results. The ankle, knee, and hip joint position profiles show a high correlation of 0.91, 0.97, 0.80 with the experimentally generated reference profiles. The faster observer dynamics and global boundness of controller result in compensation of delays. The low error and high correlation of simulation results demonstrate (1) the reliability and effectiveness of the proposed scheme for customization of human models and (2) highlight the fact that for detailed analysis and accurate simulations of STS movement the modeling scheme must consider nonlinearities of the system.

Obstructive Sleep Apnoea in Pakistan: A Single Tertiary Care Center Experience.

INTRODUCTION: Considerable interest has been shown in the field of sleep medicine in recent decades. Obstructive sleep apnoea (OSA) is a common condition that remains neglected in most parts of the world. Data are scarce, if any, when it comes to developing countries. We sought to describe the patient population in a single private tertiary care center from such a country. MATERIALS AND METHODS: A cross-sectional study that included a total of 203 patients over a five-year period was conducted. Polysomnographic studies were conducted in a dedicated sleep laboratory, under the supervision of sleep physicians. Data were described and analyzed based on clinical and self-reported outcomes, as well as polysomnographic characteristics, and compared them between genders and severity. RESULTS: With the participants having an average age of 50.84 years and a BMI of 34.7 kg/m2, the study found that the increase in age and BMI was significantly correlated with an increase in the severity of obstructive sleep apnea in the Pakistani population. There was a significant difference in sleep latency (20.6 min in women vs. 10.8 min in men; p-value = 0.001) and efficiency (63.7% in women vs. 69.8 in men; p-value = 0.02) between the two genders. Decreases in nadir saturation, total sleep time, and sleep latency were also associated with an increase in the level of severity. CONCLUSION: There is a dire need for Pakistani, and in extension Asian, medical professionals to ramp up their pace to meet the needs of their population with regard to sleep medicine.