Pubosymphyseal Urinary Fistula Following Radiation Therapy of Bladder Sarcomatoid Tumor.

Pubosymphyseal urinary fistula (PUF) is a rare condition that involves an abnormal connection between the urinary bladder and the pubic bone. It can occur after trauma, radiation therapy, or surgery to the pelvis. It is also reported with chronic indwelling Foley catheter use. In this case report, we present a 56-year-old male who developed a fistula complicated by osteomyelitis pubis following external beam radiation for a urinary bladder sarcomatoid tumor. Patients at high risk of PUF may present with urinary leakage, pelvic pain, and infection, making diagnosis challenging. The condition can lead to chronic pelvic pain and long-term opioid use if left untreated. Diagnosis is typically made through imaging studies (CT scan or MRI) and confirmed with cystoscopy. Treatment usually involves urinary diversion/surgical repair of the fistula and management of any associated infection or complications. The prognosis is generally good if the condition is diagnosed and treated promptly. While it is rare, it can have significant consequences that require prompt diagnosis and treatment.

Utility of Restaging MRI Following Neoadjuvant Chemoradiotherapy for Stage II-III Rectal Adenocarcinoma.

Background Magnetic resonance imaging (MRI) is currently utilized for the pretreatment staging of locally advanced rectal cancer; however, there is no consensus regarding the utility of repeat MRI for restaging following neoadjuvant chemoradiotherapy (CRT). In this study, we aimed to investigate the clinical utility of restaging MRI after CRT in patients with clinical stage II-III rectal cancer. Methodology We performed a retrospective observational study at a tertiary care hospital. Our study population included patients with clinical stage II-III rectal cancer treated with neoadjuvant CRT who underwent both pre- and post-CRT MRI followed by surgical resection from 2012 to 2017. MRIs were reviewed by radiologists with an interest in rectal cancer MRI imaging using a standardized template. The utility of post-CRT MRI was evaluated by assessing its impact on change in surgical planning, concordance with pathologic staging, and prediction of surgical margins. Results A total of 30 patients were included in the study; 67% had clinical stage III and 33% had stage II disease based on pre-CRT MRI. Post-CRT MRI findings did not lead to a change in the originally outlined surgical plan in any patient. Compared to pre-CRT MRI, post-CRT MRI was not significantly more accurate in predicting T stage (k = 0.483), N stage (k = 0.268), or positive surgical margins (k = 0.839). Conclusions Due to poor concordance with pathologic staging, inability to more accurately predict surgical margin status and the absence of a demonstrable change in surgical treatment, post-CRT restaging with MRI, in its current form, appears to be of limited clinical utility.

Azospirillum brasilense Chemotaxis Depends on Two Signaling Pathways Regulating Distinct Motility Parameters.

UNLABELLED: The genomes of most motile bacteria encode two or more chemotaxis (Che) systems, but their functions have been characterized in only a few model systems. Azospirillum brasilense is a motile soil alphaproteobacterium able to colonize the rhizosphere of cereals. In response to an attractant, motile A. brasilense cells transiently increase swimming speed and suppress reversals. The Che1 chemotaxis pathway was previously shown to regulate changes in the swimming speed, but it has a minor role in chemotaxis and root surface colonization. Here, we show that a second chemotaxis system, named Che4, regulates the probability of swimming reversals and is the major signaling pathway for chemotaxis and wheat root surface colonization. Experimental evidence indicates that Che1 and Che4 are functionally linked to coordinate changes in the swimming motility pattern in response to attractants. The effect of Che1 on swimming speed is shown to enhance the aerotactic response of A. brasilense in gradients, likely providing the cells with a competitive advantage in the rhizosphere. Together, the results illustrate a novel mechanism by which motile bacteria utilize two chemotaxis pathways regulating distinct motility parameters to alter movement in gradients and enhance the chemotactic advantage. IMPORTANCE: Chemotaxis provides motile bacteria with a competitive advantage in the colonization of diverse niches and is a function enriched in rhizosphere bacterial communities, with most species possessing at least two chemotaxis systems. Here, we identify the mechanism by which cells may derive a significant chemotactic advantage using two chemotaxis pathways that ultimately regulate distinct motility parameters.