Congenital Long QT Syndrome (LQTS) in Infancy: A Challenging Case.

Long QT syndrome (LQTS), is an arrhythmia disorder, related to ventricular myocardial repolarization characterized by a prolonged QT interval on the electrocardiogram that can lead to symptomatic ventricular arrhythmias and increase the mortality rate. The prevalence of congenital LQTS is about 1 in 2000 live births. Here, we report the case of a two-month-old female, with a significant family history of early death, who was brought to our emergency with an episode of blueish discoloration. The initial workup was positive for COVID-19 in the respiratory panel, so she was admitted as a case of bronchiolitis. It was a challenge because of the overlapping presentation between a serious condition and other common pediatric illnesses. Furthermore, the paper aims to increase awareness of this condition among physicians and emphasizes the importance of obtaining a complete medical history, physical examination, and family screening in selected cases to facilitate early diagnosis and timely management.

Rapid-Onset Obesity With Hypothalamic Dysfunction, Hypoventilation, Autonomic Dysregulation, and Neuroendocrine Tumor (ROHHADNET) Syndrome: A Case Report.

Here, we report the case of a rare and complex disorder, rapid-onset obesity with hypothalamic dysfunction, hypoventilation, autonomic dysregulation, and neuroendocrine tumor (ROHHADNET) syndrome, in a three-year-old girl with no significant medical history. This is the first such case reported from the UAE. ROHHADNET is a rare disorder of respiratory control and autonomic nervous system regulation with endocrine abnormalities. It typically presents in children older than 18 months with rapid weight gain. This is a challenging diagnosis as there is no clear diagnostic test, and treatment is essentially supportive. This report describes a case of ROHHADNET syndrome in a previously well child who presented with rapid weight gain followed by ophthalmoplegia, dysphagia, electrolyte disturbance, and other comorbidities. The paper outlines in detail the clinical course, investigations, and management of ROHHADNET syndrome. Cerebrospinal fluid analysis revealed oligoclonal bands, which have been reported in only two other cases of ROHHADNET syndrome. Our goal in reporting this case is to increase awareness of this condition among clinicians to facilitate early diagnosis and timely management.

Kikuchi Disease in Children: A Report of Two Cases.

Kikuchi disease (KD) is a benign self-limiting rare disease with unknown etiology. Prolonged fever with tender neck lymphadenitis is the most common presentation. Blood tests are not specific, and the final diagnosis is by biopsy. We describe two patients, ages seven and twelve years, who presented with fever and neck lymphadenitis. Both cases received antibiotics for more than two weeks without improvement. Blood work showed high inflammatory markers. The manifestation of the second case overlapped with Hashimoto's disease. The later diagnosis was confirmed by lymph node (LN) biopsy.

A Rare Infection of Chromobacterium violaceum in an Immunocompetent Patient: A Case Report.

Chromobacterium violaceum is a motile gram-negative bacillus. It lives in water and soil and rarely causes infection in immune-competent patients. It does not respond to the classical treatment and can cause a rapid and progressive illness. Hence, it should be considered in severe infection. Physicians are not generally aware of this organism as a possible cause of infection, and this increases the risk of mortality. Here, we described a case of a 17-year-old previously healthy girl who had severe necrotic cellulitis that progressed and spread rapidly over a few days despite the treatment with antibiotics. It started after a few days of swimming in a swimming pool. She was treated successfully with a broad spectrum of antibiotics and discharged home.

EPLIN-α and -ß Isoforms Modulate Endothelial Cell Dynamics through a Spatiotemporally Differentiated Interaction with Actin.

Actin-binding proteins are essential for linear and branched actin filament dynamics that control shape change, cell migration, and cell junction remodeling in vascular endothelium (endothelial cells [ECs]). The epithelial protein lost in neoplasm (EPLIN) is an actin-binding protein, expressed as EPLIN-α and EPLIN-ß by alternative promoters; however, the isoform-specific functions are not yet understood. Aortic compared to cava vein ECs and shear stress-exposed cultured ECs express increased EPLIN-ß levels that stabilize stress fibers. In contrast, EPLIN-α expression is increased in growing and migrating ECs, is targeted to membrane protrusions, and terminates their growth via interaction with the Arp2/3 complex. The data indicate that EPLIN-α controls protrusion dynamics while EPLIN-ß has an actin filament stabilizing role, which is consistent with FRAP analyses demonstrating a lower EPLIN-ß turnover rate compared to EPLIN-α. Together, EPLIN isoforms differentially control actin dynamics in ECs, essential in shear stress responses, cell migration, and barrier function.

Advanced Methods for the Investigation of Cell Contact Dynamics in Endothelial Cells Using Florescence-Based Live Cell Imaging.

Endothelial cells of the vascular system are dynamic cells whose molecular adaptability is decisive for the adjustment of homeostasis and organ perfusion. Advanced microscopic techniques, automation processing, and image analysis software was shown to improve the understanding of vascular biology. In this work, we describe advanced methods that allow investigating the dynamics of endothelial cell contacts. The development of viral vectors has contributed significantly to the genetic manipulation of endothelial cells. We used the Gibson assembly as a quick and cheap cloning system for introducing sequences into the lentiviral-based pFUGW vector. Furthermore, classical fluorescence tags such as mCherry and EGFP were compared with self-labeling tags such as Halo and SNAP for their suitability to study junction dynamics in cultured endothelium, and found the self-labeling tags as useful tools. Using such combinations, we found maintained cell junction integrity during shear stress-induced junction remodeling using VE-cadherin-EGFP. Remodeling was accompanied by VE-cadherin plaque formation, indicating that this process is mediated by the for-mation of the actin-driven junction-associated intermittent lamellipodia, JAIL. The combined methods including the Gibson assembly, lentiviral mediated gene transfer, spinning disk-based live cell imaging, and software for quantification allow analyses of the endothelial cell junction dynamics under static and under shear stress conditions.

Influence of mesterolone on satellite cell distribution and fiber morphology within maturing chicken pectoralis muscle.

Mesterolone is a synthetic oral anabolic androgenic steroid used to treat hypogonadism. There are frequent reports of mesterolone abuse in human and equine sports to increase muscle mass and strength. However, limited information is available about how this drug exerts its effects on skeletal muscle. Satellite cells (SCs) are mononuclear myogenic stem cells that contribute to postnatal muscle growth and repair. As SC activation and subsequent differentiation to new myonuclei is a major event during muscle hypertrophy, this study investigated the influence of mesterolone on SC distribution within the pectoralis muscle of chickens. Specifically, this study tested the hypotheses that mesterolone induces avian skeletal muscle hypertrophy, and that mesterolone increases the number of SCs in avian skeletal muscle. Robust immunocytochemical techniques and morphometric analyses were used to calculate the numbers of SCs and myonuclei. Also, DNA concentration and Pax7 protein levels were measured to confirm immunocytochemical findings. Mesterolone significantly increased pectoralis mass and fiber size. All SC indices and number of myonuclei increased significantly by mesterolone administration. In addition, greater DNA concentration and Pax7 protein expression were found in mesterolone-treated birds. This study indicates that mesterolone can induce avian skeletal muscle hypertrophy and that this is correlated with increased number of SCs. We suggest that SCs are key cellular intermediaries for mesterolone-induced muscle hypertrophy.

Effects of sustanon on the distribution of satellite cells and the morphology of skeletal muscle fibers during maturation.

Sustanon is one of the most commonly used anabolic androgenic drugs to increase skeletal muscle mass and strength. This drug is a blend of four esterized testosterone derivatives: Testosterone propionate, testosterone phenylpropionate, testosterone isocaproate and testosterone decanoate. Little is known about the effects of this drug on skeletal muscle at the cellular level. This study aimed to investigate the influence of Sustanon on the morphology of skeletal muscle fibers and the distribution of myogenic stem cells known as Satellite Cells (SCs) during postnatal growth. We hypothesized that Sustanon-induced skeletal muscle hypertrophy is associated with an increase in the number of SCs. Robust immunocytochemical techniques and morphometric analyses were used to calculate the numbers of SCs and myonuclei within the pectoralis muscle of chickens. Also, DNA concentration and Pax7 protein levels were measured to confirm immunocytochemical findings. Sustanon significantly increased pectoralis mass and fiber size. All SC indices and the number of myonuclei increased significantly by Sustanon administration. In addition, greater DNA concentration and Pax7 protein expression were found in Sustanon-treated birds. This study indicates that Sustanon can induce avian skeletal muscle hypertrophy and that this is correlated with increased numbers of SCs and myonuclei.