Uncommon Presentation of a Perforated Appendicitis Leading to Duodenal Fistula: Case Report and Literature Review.

Multiple types of fistulas associated with the appendix have been reported; however, duodenal fistula resulting from perforated acute appendicitis has only been documented in one previous case. In this report, we present the case of an 18-year-old male patient who was diagnosed to have a complicated appendicitis in its normal position with abscess formation. He was started on IV antibiotics and underwent a CT-guided drainage of the abscess with drain placement. Two days later due to biliary output from the drain, CT fistulography and diagnostic laparoscopy were performed that revealed the presence of a duodenal fistula. The potential for duodenal fistula formation in patients with complicated appendicitis must always be taken into consideration. Consequently, it is crucial to establish an appropriate management plan aimed at preventing additional serious complications arising from duodenal perforation.

A Case of Familial Appendiceal Neuroendocrine Tumor.

The risk of developing appendiceal neuroendocrine tumor (aNET) may be attributed to multiple factors. A familial clustering is found in less than 1% of the cases. We report the case of a 25-year-old woman who initially presented with a clinical presentation of acute appendicitis and was subsequently diagnosed with aNET by histopathological examination after an emergency appendectomy. While revealing the result to the patient, she was found to have a positive family history of appendiceal carcinoid tumor. Although rare and only found in 1% of the cases, aNET found in family history should raise the suspicion of neuroendocrine tumors in other family members.

Frequency and mutational spectrum of PIK3CA gene mutations in breast cancer patients: Largest and first report from Lebanon.

The PIK3CA pathway is one of the most frequently altered pathways in human cancers, especially in breast cancer with approximately 40% of HR+/HER2- advanced breast cancer cases exhibiting mutations in the PIK3CA gene. While the mutations can occur across the entire gene, the most common are observed in exon 9 corresponding to the helical domain, and in exon 20 encompassing the kinase domain. This study constitutes the first attempt at determining the frequency and mutational spectrum in Lebanese breast cancer patients. For this purpose, DNA samples from 280 breast cancer patients from across Lebanon were screened for PIK3CA mutations using the Therascreen® PIK3CA RGQ Real-time PCR assay. In line with previous reports, 38.57% of cases were positive for at least one PIK3CA mutation, among which approximately 59% were in exon 9 and 37% in exon 20. However, PIK3CA mutations are breast cancer are heterogeneous whereby 20% of known PIK3CA mutants might not be detected by compact PCR based assays. Thus, the adoption of comprehensive Next Generation Sequencing based panels to decipher the complete clinical, molecular and immunohistochemical profile of breast cancer tumor requires further investigation.

Common Frame Dynamics for Conically-Constrained Spacecraft Attitude Control.

Attitude control subjected to pointing constraints is a requirement for most spacecraft missions carrying sensitive on-board equipment. Pointing constraints can be divided into two categories: exclusion zones that are defined for sensitive equipment such as telescopes or cameras that can be damaged from celestial objects, and inclusion zones that are defined for communication hardware and solar arrays. This work derives common frame dynamics that are fully derived for Modified Rodrigues Parameters and introduced to an existing novel technique for constrained spacecraft attitude control, which uses a kinematic steering law and servo sub-system. Lyapunov methods are used to redevelop the steering law and servo sub-system in the common frame for the tracking problem for both static and dynamic conic constraints. A numerical example and comparison between the original frame and the common frame for the static constrained tracking problem are presented under both unbounded and limited torque capabilities. Monte Carlo simulations are performed to validate the convergence of the constrained tracking problem for static conic constraints under small perturbations of the initial conditions. The performance of dynamic conic constraints in the tracking problem is addressed and a numerical example is presented. The result of using common frame dynamics in the constrained problem shows decreased control effort required to rotate the spacecraft.

Dual-Quaternion Analytic LQR Control Design for Spacecraft Proximity Operations.

Proximity operations offer aggregate capability for a spacecraft operating in close proximity to another spacecraft, to perform on-orbit satellite servicing, or to a space object to perform debris removal. To utilize a spacecraft performing such advanced maneuvering operations and perceiving of the relative motion of a foreign spacecraft, these trajectories must be modeled accurately based on the coupled translational and rotational dynamics models. This paper presents work towards exploiting the dual-quaternion representations of spacecraft relative dynamics for proximity operations and developing a sub-optimal control law for efficient and robust maneuvers. A linearized model using dual-quaternions for the proximity operation was obtained, and its stability was verified using Monte Carlo simulations for the linear quadratic regulator solution. A sub-optimal control law using generalized higher order feedback gains in dual-quaternion form was developed based on small error approximations for the proximity operation and also verified through Monte Carlo simulations. Necessary information needed to understand the theory behind the use of the dual-quaternion is also overviewed within this paper, including the validity of using the dual-quaternions against their Cartesian or quaternion equivalents.

Derivation of All Attitude Error Governing Equations for Attitude Filtering and Control.

This article presents the full analytical derivations of the attitude error kinematics equations. This is done for several attitude error representations, obtaining compact closed-forms expressions. Attitude error is defined as the rotation between true and estimated orientations. Two distinct approaches to attitude error kinematics are developed. In the first, the estimated angular velocity is defined in the true attitude axes frame, while in the second, it is defined in the estimated attitude axes frame. The first approach is of interest in simulations where the true attitude is known, while the second approach is for real estimation/control applications. Two nonlinear kinematic models are derived that are valid for arbitrarily large rotations and rotation rates. The results presented are expected to be broadly useful to nonlinear attitude estimation/control filtering formulations. A discussion of the benefits of the derived error kinematic models is included.

Stability After Initial Decline in Coronary Revascularization Rates in the United States.

BACKGROUND: It remains uncertain how advances in revascularization techniques, availability of new evidence, and updated guidelines have influenced the annual rates of coronary revascularization in the United States. METHODS: We used the Nationwide Inpatient Sample data from 2005 to 2014 with appropriate weighting to determine national procedural volumes. To present accurately overall percutaneous coronary intervention (PCI) rates, PCI with same-day discharge numbers per year were estimated from the available literature and added to annual PCI procedures performed. RESULTS: Annual PCI rate declined from 353 per 100,000 adults in 2005 to 277 per 100,000 adults in 2009 (P < .001) but remained stable thereafter (P = .50). Annual coronary artery bypass grafting (CABG) rate declined steadily, at a shallower slope than PCI, from 120 per 100,000 in 2005 to 93 per 100,000 in 2009 (P = .02) but remained stable thereafter (P = .60). Similar trends were seen in men and women. Both PCI and CABG rates were lower in women than men over the study period (PCI, 482 to 324/100,000 in men vs 232 to 153/100,000 in women; CABG, 172 to 118/100,000 in men vs 64 to 38/100,000 in women). Annual PCI rates were higher than CABG rates in patients of all age groups including in younger patients (age < 50) and octogenarians. The proportion of coronary revascularization procedures performed per insurance type remained relatively similar across the study period. CONCLUSIONS: Annual rates of coronary revascularization have changed significantly over time, potentially because of advances in revascularization techniques, availability of new evidence, and updated guidelines. Rates of PCI declined more steeply than CABG before plateauing but remained higher than rates of CABG across the study period.

18F-fluoro-2-deoxyglucose positron emission-computed tomography in a rare cutaneous form of Rosai-Dorfman disease: A case report.

Rosai-Dorfman disease (RDD), or sinus histiocytosis with massive lymphadenopathy, commonly involves the lymph nodes but may secondarily involve the skin. Purely cutaneous disease without lymphatics or internal organ involvement occurs rarely. The present report detailed a rare case of 18F-fluoro-2-deoxyglucose positron emission-computed tomography (18FDG PET-CT) performed in a 33-year-old male soldier with a purely cutaneous form of RDD. Staging with 18FDG PET-CT was ordered prior to excisional biopsies of the aforedescribed masses and pathology reported RDD. The case demonstrated accurate localization of increased radioglucose metabolism. The present case was also discussed in light of literature data in terms of clinical features, etiologies, histology, medical imaging, therapy planning and prognosis.

Inferring microbial interaction networks from metagenomic data using SgLV-EKF algorithm.

BACKGROUND: Inferring the microbial interaction networks (MINs) and modeling their dynamics are critical in understanding the mechanisms of the bacterial ecosystem and designing antibiotic and/or probiotic therapies. Recently, several approaches were proposed to infer MINs using the generalized Lotka-Volterra (gLV) model. Main drawbacks of these models include the fact that these models only consider the measurement noise without taking into consideration the uncertainties in the underlying dynamics. Furthermore, inferring the MIN is characterized by the limited number of observations and nonlinearity in the regulatory mechanisms. Therefore, novel estimation techniques are needed to address these challenges. RESULTS: This work proposes SgLV-EKF: a stochastic gLV model that adopts the extended Kalman filter (EKF) algorithm to model the MIN dynamics. In particular, SgLV-EKF employs a stochastic modeling of the MIN by adding a noise term to the dynamical model to compensate for modeling uncertainties. This stochastic modeling is more realistic than the conventional gLV model which assumes that the MIN dynamics are perfectly governed by the gLV equations. After specifying the stochastic model structure, we propose the EKF to estimate the MIN. SgLV-EKF was compared with two similarity-based algorithms, one algorithm from the integral-based family and two regression-based algorithms, in terms of the achieved performance on two synthetic data-sets and two real data-sets. The first data-set models the randomness in measurement data, whereas, the second data-set incorporates uncertainties in the underlying dynamics. The real data-sets are provided by a recent study pertaining to an antibiotic-mediated Clostridium difficile infection. The experimental results demonstrate that SgLV-EKF outperforms the alternative methods in terms of robustness to measurement noise, modeling errors, and tracking the dynamics of the MIN. CONCLUSIONS: Performance analysis demonstrates that the proposed SgLV-EKF algorithm represents a powerful and reliable tool to infer MINs and track their dynamics.

Presence of Implantable Cardioverter-Defibrillators and Wait-List Mortality of Patients Supported with Left Ventricular Assist Devices as Bridge to Heart Transplantation.

BACKGROUND: The role of implantable cardioverter defibrillator (ICD) in reducing mortality in patients with left ventricular assisted devices (LVADs) listed for heart transplant remains unclear. We therefore, sought to interrogate whether ICDs are associated with reduced mortality in patients with LVADs listed for heart transplantation. METHODS: We searched the United Network for Organ Sharing (UNOS) Registry for LVAD patients (age≥18years) with dilated cardiomyopathies listed for heart transplantation (2008-2015). The group was matched by propensity scores with respect to presence of ICD at listing. The primary end-point was waitlist mortality, while secondary endpoints were waitlist mortality, delisting, or cardiovascular cause-specific mortality in patients with and without ICD. RESULTS: A total of 1444 LVAD patients were included in this analysis (722 with ICD, 722 without ICD). No statistically-significant differences were present between the two groups in demographics, device type, listing status, or hemodynamics. The presence of an ICD was not associated with decreased wait-list mortality (Hazard Ratio 1.19 [0.75-1.88], p=0.46), waitlist mortality/delisting (Hazard Ratio 1.20 [0.86-1.67], p=0.28), or cardiovascular wait-list mortality (HR 1.24 [0.45-3.43], p=0.67) over a median of 5.6months. Only 7 deaths occurred due to arrhythmia/cardiac arrest (2 in the ICD group and 5 in the non-ICD group). CONCLUSION: Presence of ICDs at listing in heart failure patients bridged to transplantation with durable LVADs is not associated with lower waitlist mortality, cardiovascular wait-list mortality or wait-list mortality or delisting; however, there were numerically fewer arrhythmic deaths in the ICD group. Additional prospective studies should be undertaken to confirm these findings.

A study of asymptomatic bacteriuria in Egyptian school-going children.

BACKGROUND: Urinary tract infections (UTI) are a common and important clinical problem in childhood. Upper urinary tract infections (i.e., acute pyelonephritis) may lead to renal scarring, hypertension, and end-stage renal disease. Despite the presence of simple and reliable methods of preliminary screening of children's urine, urinary tract infection continues to be under diagnosed. OBJECTIVES: The aim of this study was to establish prevalence rates of significant bacteriuria in asymptomatic school children by simple urine tests in comparison to standard urine culture techniques in Giza, Egypt. PATIENTS AND METHODS: A total of 1000 apparently healthy school going children (6-12) years, 552 boys (55.2%) and 448 girls (44.8%), were enrolled in this cross-sectional prevalence survey. RESULTS: Overall prevalence of significant bacteriuria was 6%. Higher prevalence occurred in girls (11.4%) than boys (1.6%). Escherichia coli was isolated in 35(58%) cases (3 boys and 32 girls), Staph. aureus in 13 (22%) cases (3 boys and 10 girls), Enterobacter in 6 girls (10%), Kelbsiella pneumoniae in 3 boys (5%) and Proteus vulgaris in 3 girls (5%). CONCLUSION: Asymptomatic bacteriurea could be detected by urine screening program at school age. Overall prevalence of significant bacteriuria was 6%, with predominance in girls than boys.