Preserved vagus nerve stimulator function after radiation therapy.

BACKGROUND: Epilepsy and breast cancer are both prevalent conditions. A subset of women with medically refractory epilepsy and vagus nerve stimulators (VNS) may later develop breast cancer and may require adjuvant radiation as part of their treatment regimen. However, to date, little data are available on the effects of radiation on VNS function. CASE PRESENTATION: We present a young woman with tuberous sclerosis, developmental delay, and medically refractory epilepsy who developed left-sided breast cancer. Her epilepsy became controlled with a recent addition of a VNS implanted in her left chest wall. She required adjuvant radiation therapy to her left breast, and this raised the novel question of the safety of radiation on the integrity and functioning of the device, which we explore in this article. CONCLUSION: This case is the first report of a patient with VNS for epilepsy and breast cancer who received radiation therapy proximal to the device. The device continued to function properly despite the exposure.

Development of a real-time PCR for Escherichia coli based on gadE, an acid response regulatory gene.

Increasingly, molecular methods have become important in identification and confirmation of bacteria at the species level. Rapid molecular methods provide sensitivity and specificity while reducing cost and resources. The primary goal of this study was to develop a real-time PCR assay for identification of Escherichia coli from an agar plate. GadE (gadE) directly regulates the glutamate-dependent acid response system (GDAR) in E. coli and is responsible for survival of at pH 2. Based on gene sequence data, a real-time PCR assay targeting gadE was developed for this purpose. Seventy bacterial isolates recovered from ground beef enrichments and 714 isolates from caecal contents were identified biochemically and tested with the real-time PCR assay developed in this study. The PCR assay and the biochemical identification had 100% agreement on the tested isolates. The gadE real-time PCR assay was demonstrated in this study to be an inexpensive, reliable method for confirming E. coli colonies within 1.5 h from an agar plate, thereby saving on final identification time.

Preoperative versus postoperative radiotherapy for locally advanced gastroesophageal junction and proximal gastric cancers: a comparison of normal tissue radiation doses.

Locoregional relapse occurs in over half of gastric cancer patients who undergo potentially curative resection. Adjuvant chemoradiation reduces locoregional relapse, but often requires irradiating large fields and is limited by poor patient tolerance. This study explores the potential dosimetric benefit in reducing the radiation dose to normal structures by treating gastroesophageal (GE) junction/proximal gastric cancers with preoperative rather than adjuvant radiotherapy. Five cases of GE junction/proximal gastric cancer patients treated postoperatively with curative intent were selected. The actual target contours were then modified to reflect hypothetical target volumes which would have been used had the patients been treated preoperatively. Hypothetical preoperative treatment plans were generated for each patient based on these modified contours. The hypothetical preoperative treatment plans were then compared to the actual postoperative plans with respect to dose-volume parameters including lung mean dose, lung V20, heart V20 and V30, and mean doses to abdominal structures. Target volumes were smaller with preoperative treatment, with an average reduction of 23%. Comparative dose-volume histogram (DVH) analysis showed the resultant composite lung doses were reduced in the preoperative plans by 50-79%. In all patients, the proportion of lungs receiving at least 20 Gy (V20) was substantially reduced using preoperative treatment (1.9% vs. 9.7% in the 3-D conformal patient; mean of 3.1% vs. 17.6% in the intensity modulated radiation therapy patients). Likewise, the volume of heart receiving at least 30 Gy was dramatically reduced in all preoperative plans (15.8% vs. 35.4%). Doses to the kidneys, liver and spinal cord were comparable in both approaches. Preoperative treatment of GE junction and proximal gastric cancer patients offers the potential to decrease the radiation dose received by normal thoracic structures.

Radiation dose reduction in four-dimensional computed tomography.

Four-dimensional (4D) CT is useful in many clinical situations, where detailed abdominal and thoracic imaging is needed over the course of the respiratory cycle. However, it usually delivers a larger radiation dose than the standard three-dimensional (3D) CT, since multiple scans at each couch position are required in order to provide the temporal information. Our purpose in this work is to develop a method to perform 4D CT scans at relatively low current, hence reducing the radiation exposure of the patients. To deal with the increased statistical noise caused by the low current, we proposed a novel 4D penalized weighted least square (4D-PWLS) smoothing method, which can incorporate both spatial and phase information. The 4D images at different phases were registered to the same phase via a deformable model, thereby, a regularization term combining temporal and spatial neighbors can be designed for the 4D-PWLS objective function. The proposed method was tested with phantom experiments and a patient study, and superior noise suppression and resolution preservation were observed. A quantitative evaluation of the benefit of the proposed method to 4D radiotherapy and 4D PET/CT imaging are under investigation.

Plasmablastic lymphoma presenting in a human immunodeficiency virus-negative patient: a case report.

Plasmablastic lymphoma (PBL), an aggressive non-Hodgkin's lymphoma that carries a poor prognosis, previously has been identified almost exclusively in patients infected with the human immunodeficiency virus (HIV). We present a case of a 42-year-old HIV-negative patient presenting with an isolated nasal cavity mass, the typical presentation for PBL. The patient was given systemic chemotherapy, central nervous system prophylaxis, and consolidative locoregional radiotherapy and achieved a complete clinical response. This case suggests PBL should be considered in HIV-negative patients with characteristic findings.

Long-term amikacin use. Effects on aminoglycoside susceptibility patterns of gram-negative bacilli.

Amikacin sulfate was first used sparingly at our cancer center in 1976; since 1979, it has been the only aminoglycoside used for systemic cancer therapy for patients with granulocytopenia. As the development of resistance has been correlated with antibiotic use over time, we wished to determine if prolonged use of amikacin in our patients had led to increased amikacin resistance. A total of 1,129 strains were recovered from 315 patients during a 13-month period. Each species isolated per patient was considered once. Seven percent of the patients had amikacin-resistant strains (2.7% of isolates), and 10% of patients had gentamicin-resistant strains (4% of isolates). Amikacin resistance was significantly less than in an earlier study. Unrestricted use of amikacin has not led to a concomitant increase in amikacin resistance in gram-negative bacilli.