Type III Secretion-Dependent Sensitivity of Escherichia coli O157 to Specific Ketolides

A subset of Gram-negative bacterial pathogens uses a type III secretion system (T3SS) to open up a conduit into eukaryotic cells in order to inject effector proteins. These modulate pathways to enhance bacterial colonization. In this study, we screened established bioactive compounds for any that could repress T3SS expression in enterohemorrhagic Escherichia coli (EHEC) O157. The ketolides telithromycin and, subsequently, solithromycin both demonstrated repressive effects on expression of the bacterial T3SS at sub-MICs, leading to significant reductions in bacterial binding and actin-rich pedestal formation on epithelial cells. Preincubation of epithelial cells with solithromycin resulted in significantly less attachment of E. coli O157. Moreover, bacteria expressing the T3SS were more susceptible to solithromycin, and there was significant preferential killing of E. coli O157 bacteria when they were added to epithelial cells that had been preexposed to the ketolide. This killing was dependent on expression of the T3SS. Taken together, this research indicates that the ketolide that has accumulated in epithelial cells may traffic back into the bacteria via the T3SS. Considering that neither ketolide induces the SOS response, nontoxic members of this class of antibiotics, such as solithromycin, should be considered for future testing and trials evaluating their use for treatment of EHEC infections. These antibiotics may also have broader significance for treating infections caused by other pathogenic bacteria, including intracellular bacteria, that express a T3SS.     

Contrast‐Enhanced Echocardiographic Evaluation of a Giant Saphenous Vein Graft Aneurysm

A 61‐year‐old man presented with unstable angina 16 years after undergoing coronary artery bypass grafting with a left internal mammary artery graft to the left anterior descending coronary artery and a sequential saphenous vein graft (SVG) to the right coronary artery and an obtuse marginal branch. Transthoracic echocardiography (TTE) with a Philips iE33 machine and an S5 transducer revealed a 5.3 cm × 4.6 cm mass with a central echolucent area, surrounded by a peripheral zone of increased echodensity adjacent to, and partially compressing, the right atrium. Contrast echocardiography following an intravenous bolus injection of Definity revealed late appearance of contrast within the mass consistent with a giant SVG aneurysm. Coronary artery bypass graft angiography revealed a giant aneurysm in the SVG proximal to the RCA anastomosis; the distal limb of the graft to the obtuse marginal branch was occluded. Under intravascular ultrasound guidance, a 7‐mm spider filter was placed in the distal graft; then, a 6 mm × 10 cm Viabahn self‐expanding nitinol polyethylene terephthalate‐covered stent was deployed in the SVG with good seal zones proximally and distally. A follow‐up contrast‐enhanced transthoracic echocardiogram 1 day postprocedure revealed partial thrombosis of the aneurysm cavity. Ultrasound contrast did not appear in the aneurysm following intravenous injection, consistent with complete exclusion from the systemic circulation. This is the first report demonstrating feasibility of contrast‐enhanced transthoracic echocardiography for the diagnosis of SVG aneurysm and confirming procedural success by documenting exclusion from the systemic circulation following intervention.     

Prevalence and correlates of chronic fatigue syndrome and post-traumatic stress disorder after the outbreak of the COVID-19

Journal of NeuroVirology - As the SARS-COV-2 becomes a global pandemic, many researchers have a concern about the long COVID-19 complications. Chronic fatigue syndrome/myalgic encephalomyelitis...     

Effectiveness of an early mobility protocol for stroke patients in Intensive Care Unit

Objectives:To evaluate the effectiveness of an early mobility protocol for stroke patients in the intensive care unit.Methods:Participants were patients with first or recurrent stroke (n=60, age=49.02±6.36 years, body mass index=32.95±5.67 kg/m²) admitted to the intensive care stroke unit in general hospitals, Riyadh during October and December 2016. Single group pretest-posttest design involving an early mobility protocol was started within first 24 hours admission. Pre and post measurements of muscle strength, pulmonary function and quality of life were carried out.Results:There were significant improvements in muscle strength of upper and lower extremities´ muscles after treatment (p<0.05), pulmonary functions including Forced Vital Capacity, Forced Expiratory Volume 1 (p<0.05) and quality of life, namely, Barthel Index and modified Rankin Scale (p<0.01).Conclusion:This study demonstrates that initiating an early mobility protocol is safe and effective for intensive care unit stroke patients and supports introducing the current protocol as a standard protocol in neurogenic Intensive Care Units.

Stroke is a life-threatening condition caused by interruption of the blood supply to any part of the brain. Stroke causes acute neurological disorders and long-term disabilities and imposes economic, social and health impacts on individuals and their families.1 Survivors of stroke are left with mental and physical disabilities that cause social and economic burdens and impair quality of life (QOL). In Saudi Arabia stroke is becoming a rapidly increasing problem and a primary cause of morbidity and mortality.2 Worldwide the incidence of first-time stroke was 17 million during 1990-2000.3 Cerebrovascular diseases including stroke is a leading cause of mortality,4 and stroke is the fifth leading cause of death, but it remains the first cause of disability in the USA.5 By 2030 there will be almost 12 million stroke deaths and 70 million stroke survivors globally.6 Stroke has an adverse influence on the QOL of patients. The onset of stroke is sudden, and unlike other disabling conditions, it leaves patients and their family’s ill prepared for its sequelae.7 Stroke may create unique conditions that affect the patients’ QOL, involving dysfunctions in physical, emotional, memory, thinking, and social interactions.8Stroke is an urgent health care issue. It is a common cause of the hospital admissions. Immediate admission to the neuro-intensive care unit can facilitate early stroke treatment strategies.9 Stroke patients in the intensive care unit (ICU) experience a decrease in physical activity that represents a significant stress on the body and leads to a considerable decrease in functional status, increases morbidity, mortality rate, and duration of hospital stay and cost of care.10 In addition to comorbid diseases, patients on mechanical ventilation have many barriers to mobility because they are surrounded by tubes, catheters, life support and monitoring equipment. Additionally, other factors besides weakness, such as sleep loss, lack of social communication, nutritional status, sedation, and an ICU culture that encourages bed rest further contribute to functional deterioration.11 There is considerable loss of the muscle mass during the initial weeks of immobility in the ICU, therefore its management is inherently related to QOL after discharge.12 Considerable published evidence indicates that patients in ICUs have high morbidity and mortality, high costs of care and a marked decline in functional status.13,14Early and progressive mobilization program has been described as a key component for patients in the ICU. It may decrease post stroke complications such as infections, deep venous thrombosis, pneumonia, pressure ulcers, falls and de-conditioning with bed rest.15 It has been recognized that mobilization of post stroke patients is essential to prevent hospital-associated complications, functional decline and facilitate recovery.16 Moreover, the benefits of early mobilization include decreased ICU-acquired weakness, improved functional recovery within hospital,17 Effective stroke intervention begins the day the patient has a stroke.18 It has a positive effect on patient functional ability, promotes positive psychological effects and improves walking at hospital discharge and reduces hospital length of stay.19 While on the other hand, long term inactivity may affect the patients’ physical, social, emotional, behavioral, and psychological pattern.20 In addition, secondary changes associated with stroke-related inactivity include muscle atrophy, a shift in muscle fiber type to a greater predominance of fast-fatigable, insulin-resistant fibers, loss of cardiovascular fitness, and increased intramuscular fat.21 Therefore, early mobilization program which is a complex intervention that needs crucial patient assessment and management, as well as interdisciplinary team collaboration and training.22,23 The early mobilization may improve patient outcomes and recovery.24 Few studies have investigated the role of increased mobility in ICU patients. Therefore, this prospective intervention trial evaluated the effectiveness of an early mobility program administered by physical therapists and nursing personnel for stroke patients admitted in ICU.     

Selecting a Medical School Advisor

Having an advisor offers medical students many advantages, including increased likelihood of matching into their top choices. Interestingly, students who choose emergency medicine (EM) as a specialty are more likely to seek advising. However, finding and optimally utilizing an EM faculty advisor is often challenging for the medical student. In this article, we tackle the different ways to seek advising, including the ‘virtual advisor program’ implemented by the Society for Academic Emergency Medicine, the ‘e-Advisor Program’ instigated by the Clerkship Director in EM Group, the ‘member exclusive mentorship program’ of the Emergency Medicine Residency Association, as well as peer-based mentoring. More so, we discuss the consensus recommendations developed by the Student Advising Task Force to guide both students planning to apply to EM and their advisors to ensure high-caliber advising.     

Metformin ameliorates the age‐related changes of d‐galactose administration in ovariectomized mice

Metformin (Met) has been shown to have pleiotropic effects such as neuroprotective, antioxidant, and anti‐inflammatory properties making that a potential candidate for the treatment of central nervous system (CNS) disorders. This study was designed to investigate the possible effect of Met on the d ‐galactose (d ‐gal)‐induced aging in ovariectomized mice. The female mice underwent bilateral ovariectomy. d ‐gal was administered orally at a dose of 500 mg/kg, and Met was administrated orally at doses of 1 and 10 mg/kg for 6 weeks. Anxiety‐like behavior was evaluated by the elevated plus‐maze. Physical power was assessed by vertical grid holding test and forced swimming capacity test. The brains were assessed for the level of superoxide dismutase (SOD) and brain‐derived neurotrophic factor (BDNF). Ovariectomy caused anxiety and declined the physical power as well as BDNF and SOD levels. d ‐gal administration in ovariectomized mice exacerbated these deleterious effects. Met hampered the anxiety‐like behavior and strengthened the physical power of d ‐gal‐treated ovariectomized mice. Met also increased the SOD and BDNF levels in the brains of d ‐gal‐treated ovariectomized animals. Based on the obtained results, we suggest Met administration as a novel therapeutic approach for the treatment of age‐related conditions in the absence of female sex hormones.     

The ALK inhibitor ASP3026 eradicates NPM-ALK+ T-cell anaplastic large-cell lymphoma in vitro and in a systemic xenograft lymphoma model

NPM-ALK⁺ T-cell anaplastic large-cell lymphoma (ALCL) is an aggressive type of cancer. Standard treatment of NPM-ALK⁺ ALCL is CHOP polychemotherapy. Although patients initially respond favorably to CHOP, resistance, relapse, and death frequently occur. Recently, selective targeting of ALK has emerged as an alternative therapeutic strategy. ASP3026 is a second-generation ALK inhibitor that can overcome crizotinib resistance in non-small cell lung cancer, and is currently being evaluated in clinical trials of patients with ALK⁺ solid tumors. However, NPM-ALK⁺ ALCL patients are not included in these trials. We studied the effects of ASP3026 on NPM-ALK⁺ ALCL cell lines in vitro and on systemic lymphoma growth in vivo. ASP3026 decreased the viability, proliferation, and colony formation, as well as induced apoptotic cell death of NPM-ALK⁺ ALCL cells. In addition, ASP3026 significantly reduced the proliferation of 293T cells transfected with NPM-ALK mutants that are resistant to crizotinib and downregulated tyrosine phosphorylation of these mutants. Moreover, ASP3026 abrogated systemic NPM-ALK⁺ ALCL growth in mice. Importantly, the survival of ASP3026-treated mice was superior to that of control and CHOP-treated mice. Our data suggest that ASP3026 is an effective treatment for NPM-ALK⁺ ALCL, and support the enrollment of patients with this lymphoma in the ongoing clinical trials.     

Combining the ‘bottom up’ and ‘top down’ approaches in pharmacokinetic modelling: fitting PBPK models to observed clinical data

Pharmacokinetic models range from being entirely exploratory and empirical, to semi-mechanistic and ultimately complex physiologically based pharmacokinetic (PBPK) models. This choice is conditional on the modelling purpose as well as the amount and quality of the available data. The main advantage of PBPK models is that they can be used to extrapolate outside the studied population and experimental conditions. The trade-off for this advantage is a complex system of differential equations with a considerable number of model parameters. When these parameters cannot be informed from in vitro or in silico experiments they are usually optimized with respect to observed clinical data. Parameter estimation in complex models is a challenging task associated with many methodological issues which are discussed here with specific recommendations. Concepts such as structural and practical identifiability are described with regards to PBPK modelling and the value of experimental design and sensitivity analyses is sketched out. Parameter estimation approaches are discussed, while we also highlight the importance of not neglecting the covariance structure between model parameters and the uncertainty and population variability that is associated with them. Finally the possibility of using model order reduction techniques and minimal semi-mechanistic models that retain the physiological-mechanistic nature only in the parts of the model which are relevant to the desired modelling purpose is emphasized. Careful attention to all the above issues allows us to integrate successfully information from in vitro or in silico experiments together with information deriving from observed clinical data and develop mechanistically sound models with clinical relevance.