Surgical incision induces phosphorylation of AMPA receptor GluR1 subunits at Serine-831 sites and GluR1 trafficking in spinal cord dorsal horn via a protein kinase Cγ-dependent mechanism

Spinal α-amino-3-hydroxy-5-methy-4-isoxazole propionate (AMPA) receptor plays an important role in acute pain induced by surgical tissue injuries. Our previous study has shown that the enhanced phosphorylation of AMPA receptor GluR1 subunits at Serine-831 sites by protein kinase C (PKC) in the spinal cord dorsal horn is involved in post-surgical pain hypersensitivity. However, which isoforms of PKC are responsible for the phosphorylation of AMPA receptor GluR1 subunits at Serine-831 sites remains to be established. In the present study, using an animal model of postoperative pain, we found that surgical tissue injuries enhanced the membrane translocation level of PKCγ, but not PKCα, βI, and βII, and induced the trafficking of GluR1, but not GluR2 into neuronal plasma membrane. Intrathecal (i.t.) pretreatment of small interfering RNA targeting PKCγ to reduce the PKCγ expression in the spinal cord significantly attenuated the pain hypersensitivity and inhibited the phosphorylation of AMPA receptor GluR1 subunits at Serine-831 sites as well as GluR1 membrane trafficking. Our study indicates that the surgical incision-induced phosphorylation of AMPA receptor GluR1 subunits at Serine-831 sites and GluR1 trafficking are regulated by a PKCγ-dependent mechanism.

Current conduct of deep hypothermic circulatory arrest in China

INTRODUCTION

Deep hypothermic circulatory arrest for adult aortic arch repair is still associated with significant mortality and morbidity. Furthermore, there is still significant variation in the conduct of this complex perioperative technique. This variation in deep hypothermic circulatory arrest practice has not been adequately characterized and may offer multiple opportunities for outcome enhancement. The hypothesis of this study was that the current practice of adult deep hypothermic circulatory arrest in China has significant variations that might offer therapeutic opportunities for reduction of procedural risk.

METHODS

An adult deep hypothermic circulatory arrest questionnaire was developed and then administered at a thoracic aortic session at the International Cardiothoracic and Vascular Anesthesia Congress convened in Beijing during 2010. The data was abstracted and analyzed.

RESULTS

The majority of the 56 respondents were anesthesiologists based in China at low-volume deep hypothermic circulatory arrest centers. The typical aortic arch repair had a prolonged deep hypothermic circulatory arrest time at profound hypothermia. The target temperature for deep hypothermic circulatory arrest was frequently measured distal to the brain. The most common perfusion adjunct was antegrade cerebral perfusion, typically monitored with radial arterial pressure and cerebral venous oximetry. The preferred neuroprotective agents were steroids and propofol.

CONCLUSIONS

The identified opportunities for outcome improvement in this delineated deep hypothermic circulatory arrest model include nasal/tympanic temperature measurement and routine cerebral perfusion, preferably with unilateral antegrade cerebral perfusion monitored with radial artery pressure and cerebral oximetry. Development and dissemination of an evidence-based consensus would enhance these practice-improvement opportunities.

Effect of greyscale liquid crystal displays of different resolutions on observer performance during detection of small solitary pulmonary nodules

OBJECTIVE

The aim of this study was to evaluate the effect of monochrome liquid crystal displays (LCDs) with different resolutions on observer performance during detection of small solitary pulmonary nodules.

METHODS

Chest images of digital radiography were selected online from the hospital's picture archiving and communication system. Of the 164 images selected, small solitary non-calcified pulmonary nodules were present in 63 images and absent in 101 images. Observer performance was assessed among 3 extremely experienced, 3 very experienced and 3 moderately experienced radiologists, who independently interpreted these images on 2, 3 and 5 megapixel greyscale LCDs. A five-point confidence level rating scale was used to represent the presence of nodules: definite absence, probable absence, indetermination, probable presence and definite presence. The observers were requested to rank each image on the given display according to the presence of the pulmonary nodule. Observer performance was analysed in terms of receiver operating characteristics (ROCs).

RESULTS

The areas under the ROC curves which represented the observer performance for the 2, 3 and 5 megapixel LCDs were found to be 0.705, 0.722 and 0.764, respectively, for the extremely experienced radiologists; 0.687, 0.712 and 0.721, respectively, for the very experienced radiologists; and 0.689, 0.696 and 0.711, respectively, for the moderately experienced radiologists. These differences were not statistically significant.

CONCLUSION

The observer performances for detection of small solitary non-calcified pulmonary nodules by radiologists with varying degrees of experience were comparable between the 2, 3 and 5 megapixel monochrome LCDs.

WE-G-213CD-05: Beam's-Eye-View Prostate Motion Detection during Arc Radiotherapy

PURPOSE

To track prostate motion during clinical arc radiotherapy using a novel statistical motion tracking algorithm in both phantom and patient systems.

METHODS

For the phantom study, a dynamic phantom with a custom tumor model and radiopaque fiducials was used. For the patient study, the clinical data from two prostate patients were acquired during volumetric modulated arc therapy (VMAT). For each patient, two gold fiducials (X-Mark, 1cm and 2cm in length) were implanted in the prostate. A total of 35 fractions with 2-field full arcs were delivered. Beam's-eye- view (BEV) images were acquired in cine mode every five fractions at a frame rate of 2 fps.The prostate motion was measured by two sequential steps: fiducial detection and motion estimation. In the first step, a wavelet- based block matching filter was used to suppress the noise and enhance the fiducials in the BEV images. A trajectory of detected fiducials was generated along the projection angles. Sequentially, the prostate motion was tracked using a statistical maximum a posteriori (MAP) algorithm. The 3-D fiducial position was estimated by maximizing the probability of displacement of 2-D projections.

RESULTS

A total of 8,400 BEV images were processed for this study. The phantom experiments showed that the baseline accuracy of estimation is 0.69+/-0.56 mm. For patient 1, intra- fraction prostate motion was measured to be 0.98+/-0.51 mm for all fractions, and individual fraction motion less than 1 mm. For patient 2, intra- fraction motion was 1.12+/-0.65 mm for all fractions. However, an exceptionally large displacement was measured as 4.9+/-0.74mm in one of the fractions.

CONCLUSIONS

Prostate motion during arc-therapy can be rigorously tracked to an accuracy of one millimeter. This technique is well suited for in-treatment room target tracking and post-therapy evaluation. Varian Medical Systems Inc.

A case of occult bowel perforation after a cycle of chemotherapy for advanced epithelial ovarian carcinoma

Occult bowel perforation is a rare complication in chemotherapy of advanced epithelial ovarian cancer (EOC). The authors present a case of a 75-year-old woman who had appendectomy due to suppurative appendicitis five years prior, that experienced an occult bowel perforation resulting in continuous decline of electrolytes after a single cycle of nedaplatin (NDP) and paclitaxel during neoadjuvant treatment of advanced EOC. To the authors' knowledge, this is the first reported case of an occult bowel perforation after neoadjuvant chemotherapy (NAC) for ovarian cancer. The complication was highly suggestive of a cell lysis mechanism for the perforation.

Uterine sarcoma with abdominal wall metastasis following laparoscopy: case report

PURPOSE

This work aimed to prevent artificial implantation in laparoscopic surgery for gynecological tumors.

METHODS

A case of uterine sarcoma with abdominal wall metastasis following laparoscopy was analyzed for clinical features.

RESULTS

A diagnosis of uterine sarcoma was made in Stage IV and the previous laparoscopic surgery had caused artificial abdominal wall metastasis.

CONCLUSIONS

We need to protect the puncture port in laparoscopic surgery of gynecological tumors to prevent artificial implantation.