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Abstract: The human pathogen Campylobacter jejuni utilizes oxidative phosphorylation to meet all of its energy demands. The genome sequence of this bacterium encodes a number of respiratory enzymes in a branched electron transport chain that predicts the utilization of a number of electron transport chain donor and acceptor molecules. Three of these electron donor enzymes: hydrogenase, formate dehydrogenase, and 2-oxoglutarate:acceptor oxidoreductase (OOR), oxidize hydrogen, formate and α-ketoglutarate as electron donors, respectively. Mutations were created in these donor enzymes to isolate mutants in hydrogenase (HydB::CM), formate dehydrogenase (Fdh::CM), and OOR (OorB::CM), as well as a strain with insertions in both hydrogenase and formate dehydrogenase (Hyd::Fdh). These mutants are deficient in their respective enzyme activities and do not reduce the components of the electron transport chain when provided with their respective substrates. The presence of either hydrogen or formate in the media stimulated the growth of wild type (WT) C. jejuni (but not the associated mutant strains) and at least one of these alternative substrates is required for growth of the OOR mutant strain OorB::CM. Finally, the importance of hydrogenase, formate dehydrogenase and OOR as well as the complex I of C. jejuni are elucidated by chicken colonization assays, where the double mutant Hyd::Fdh, OorB::CM and nuo mutants are severely impaired in host colonization. [Copyright &y& Elsevier]

Compartment syndrome is usually due to trauma but can also have atraumatic causes. It is defined as a compromise of neurovascular and muscle function that presents symptomatically with the six P's: pain, pallor, paresthesia, paralysis, poikilothermia, and pulselessness. Diagnosis is confirmed by a delta pressure of <30 mmHg (diastolic blood pressure minus the compartment pressure). This case details a 15-year-old male football player with atraumatic compartment syndrome in the lateral compartment of the right lower leg. Symptoms of swelling and pain began 2 weeks before presentation after the patient was "juked." The patient's symptoms improved after a week of rest but worsened when he returned to practice. In the emergency department, the patient was able to ambulate with pain and declined pain medication. Examination revealed severe tenderness, mildly decreased strength, decreased sensation, and edema in the lateral compartment via bedside ultrasound. Because of the concern for compartment syndrome, pressure was checked with a disposable manometer (Compass CT disposable pressure transducer) revealing a delta pressure of 26 mmHg. The patient consequently underwent fasciotomy, eventually returning to baseline function without deficits. Awareness of this atypical presentation of compartment syndrome will assist providers in making a critical diagnosis and preventing severe complications and disability. This case also demonstrates the potential of disposable pressure transducers for cost-effective and accurate diagnostic confirmation of compartment syndrome in the emergency department. [ABSTRACT FROM AUTHOR]

Background: Headaches and visual complaints are common conditions encountered in the emergency department. While a patient's age, risk factors, and comorbidities often aid in risk stratification and guide emergency department evaluation, atypical presentations of serious disease may still occur in young otherwise healthy patients CASE: In this vignette we discuss a case of ocular (choroidal) melanoma in a 21 year-old female patient who presented with recurrent photopsia and headaches.Discussion: Ocular melanoma is the most common non-skin melanoma and should be considered by the emergency physician for patients with visual deficits. Likely presentations and risk factors for ocular melanoma will be discussed as well as emergency department and specialty management. [ABSTRACT FROM AUTHOR]