Glutamate metabolism in temporal lobe epilepsy as revealed by dynamic proton MRS following the infusion of [U13-C] glucose.

Focal metabolic dysfunction commonly observed in temporal lobe epilepsy (TLE), and is associated with the development of medical intractability and neurocognitive deficits. It has not been established if this dysfunction is due to cell loss or biochemical dysfunction in metabolic pathways. To explore this question, dynamic 1H MRS following an infusion of [U13- C] glucose was performed to measure glutamate (Glu) metabolism. Subjects (n=6) showed reduced Glu levels (p<0.01) in the ipsilateral mesial temporal lobe (MTL) compared with controls (n=4). However, the rate of 13C incorporation into Glu did not differ between those with epilepsy and controls (p=0.77). This suggests that reduced Glu concentrations in the region of the seizure focus are not due to disruptions in metabolic pathways, but may instead be due to neuronal loss or simplification.

Increased infarct wall thickness by a bio-inert material is insufficient to prevent negative left ventricular remodeling after myocardial infarction.

BACKGROUND: Several injectable materials have been shown to preserve or improve cardiac function as well as prevent or slow left ventricular (LV) remodeling post-myocardial infarction (MI). However, it is unclear as to whether it is the structural support or the bioactivity of these polymers that lead to beneficial effects. Herein, we examine how passive structural enhancement of the LV wall by an increase in wall thickness affects cardiac function post-MI using a bio-inert, non-degradable synthetic polymer in an effort to better understand the mechanisms by which injectable materials affect LV remodeling. METHODS AND RESULTS: Poly(ethylene glycol) (PEG) gels of storage modulus G' = 0.5±0.1 kPa were injected and polymerized in situ one week after total occlusion of the left coronary artery in female Sprague Dawley rats. The animals were imaged using magnetic resonance imaging (MRI) at 7±1 day(s) post-MI as a baseline and again post-injection 49±4 days after MI. Infarct wall thickness was statistically increased in PEG gel injected vs. control animals (p<0.01). However, animals in the polymer and control groups showed decreases in cardiac function in terms of end diastolic volume, end systolic volume and ejection fraction compared to baseline (p<0.01). The cellular response to injection was also similar in both groups. CONCLUSION: The results of this study demonstrate that passive structural reinforcement alone was insufficient to prevent post-MI remodeling, suggesting that bioactivity and/or cell infiltration due to degradation of injectable materials are likely playing a key role in the preservation of cardiac function, thus providing a deeper understanding of the influencing properties of biomaterials necessary to prevent post-MI negative remodeling.

Automated ischemic lesion detection in a neonatal model of hypoxic ischemic injury.

PURPOSE: To develop and compare an automated detection system for ischemic lesions in a neonatal model of bilateral carotid artery occlusion with hypoxia (BCAO-H) from T2 weighted MRI (T2WI) to the currently used "gold standard" of manual segmentation. MATERIALS AND METHODS: Forty-three P10 BCAO-H rat pups and 8 controls underwent T2WI at 1 day and 28 days. A computational imaging method, Hierarchical Region Splitting (HRS), was developed to automatically and rapidly detect and quantify 3D lesion and normal appearing brain matter (NABM) volumes. RESULTS: HRS quantified lesion and NABM volumes within 15 s in comparison to 3 h for its manual counterpart, with a high correlation for injury (r(2) = 0. 95; P = 8.6 × 10(-7) ) and NABM (r(2) = 0. 92; P = 1.4 × 10(-22) ). Average lesion volumes for mild, moderate, and severe injuries were 3.85%, 28.85%, and 52.98% for HRS and 0.51%, 24.22%, and 48.74% for manual detection. Lesion volumes and locations were similar for both methods (sensitivity: 0.82, specificity: 0.86, and similarity: 1.47). CONCLUSION: HRS is an accurate, objective, and rapid method to quantify injury evolution in neonatal hypoxic ischemic injury models.

Results from the survey for preservation of adolescent reproduction (SPARE) study: gender disparity in delivery of fertility preservation message to adolescents with cancer.

PURPOSE: Diminished reproductive capacity is a devastating consequence of life-sparing therapies for childhood malignancy. In 2006, the American Society of Clinical Oncology (ASCO) published fertility preservation recommendations (ASCOR) emphasizing the importance of early discussion and intervention for fertility preservation strategies. Using the Survey for Preservation of Adolescent REproduction (SPARE), we sought to determine fertility preservation attitudes and practice patterns post-ASCOR from pediatric oncology specialists nationwide. MATERIALS AND METHODS: The SPARE survey consists of 22 questions assessing pediatric oncology specialists' attitudes and practice patterns toward fertility preservation. Broad perspectives on fertility preservation, including a willingness to discuss fertility, knowledge of current fertility preservation methods and awareness of ASCOR, were assessed. RESULTS: The majority of respondents acknowledged that fertility threats are a major concern for them and agreed that all pubertal cancer patients should be offered a fertility consultation, but only 46% reported they refer male pubertal cancer patients to a fertility specialist prior to cancer treatment >50% of the time, and only 12% reported they refer female pubertal cancer patients to a fertility specialist prior to cancer treatment > 50% of the time. While 44% of respondents were familiar with the 2006 ASCOR, only 39% of those utilized them to guide decision-making in greater than half of their patients. CONCLUSION: Our study demonstrates pediatric oncologists' motivation to preserve fertility in pediatric cancer patients; however, barriers to both gamete cryopreservation and referral to fertility specialists persist. Female pubertal patients are referred to fertility preservation specialists with much less frequency than are male pubertal patients, highlighting a disparity.

Frequency and methods of gastrojejunal tube replacement in children.

Gastrojejunal (GJ) tubes are increasingly used for enteral feeding in children in whom gastric feeding either is not tolerated or is contraindicated. The most common complications associated with GJ tube use are mechanical failure (clogging, cracking, deterioration) and dislodgement. Less common, but more significant, complications are bowel perforation, aspiration, and feeding intolerance. Some of these complications may be prevented by replacing GJ tubes at regular intervals. Methods to direct a GJ tube include 1) guidewire, 2) gastroduodenoscopy-guidewire, 3) esophagogastroduodenoscopy-forceps, and 4) fluoroscopy-guidewire. Clinical experience to determine the ideal method and optimal timing of GJ tube replacement is evolving. GJ tube replacement using a guidewire through the prior GJ tube, without endoscopy, fluoroscopy, or sedation, is the least risky method, but is also the least likely to be successful.

Pathologic outcomes during the learning curve for robotic-assisted laparoscopic radical prostatectomy.

OBJECTIVE: We report our initial experience with 62 patients undergoing robotic-assisted laparoscopic prostatectomy (RALP), focusing on the primary parameter of positive surgical margins. The authors demonstrate that excellent oncologic outcomes can be attained with a less steep learning curve than previously hypothesized. MATERIALS AND METHODS: The first 62 patients undergoing RALP by a single physician (DPD) at our institution between November 2005 and August 2007 were retrospectively assessed. Surgical pathology records were reviewed for Gleason score, pathologic tumor stage, nodal status, location of prostate cancer within the specimen, extracapsular extension, surgical margin status, presence of perineural invasion, tumor volume, and weight of the surgical specimen. Margin status was determined using surgical specimens only, and not intraoperative frozen sections. All cases in this series were completed using the four-arm da Vinci Robotic System (Intuitive Surgical, Sunnyvale, California). RESULTS: Sixty-one patients had prostate cancer on their final surgical pathology specimens. Pathologic stage T2 and stage T3 patients were 88.7% and 9.7% of all cases, respectively. The pathologic Gleason score was 7 or greater in 62.3%. Our overall positive surgical margin rate was 3.3%. Patients with pathologic T2 and T3 disease had a positive surgical margin rate of 1.8% and 16.7%, respectively. CONCLUSIONS: Our study suggests that RALP can have equal if not better pathologic outcomes compared to open radical prostatectomy even during the initial series of cases. We argue that the learning curve for RALP is shorter than previously thought with respect to oncologic outcomes, and concerns asserting that lack of tactile feedback leads to poor oncologic outcomes are unfounded.

Pathologic outcomes during the learning curve for robotic-assisted laparoscopic radical prostatectomy

OBJECTIVE: We report our initial experience with 62 patients undergoing robotic-assisted laparoscopic prostatectomy (RALP), focusing on the primary parameter of positive surgical margins. The authors demonstrate that excellent oncologic outcomes can be attained with a less steep learning curve than previously hypothesized. MATERIALS AND METHODS: The first 62 patients undergoing RALP by a single physician (DPD) at our institution between November 2005 and August 2007 were retrospectively assessed. Surgical pathology records were reviewed for Gleason score, pathologic tumor stage, nodal status, location of prostate cancer within the specimen, extracapsular extension, surgical margin status, presence of perineural invasion, tumor volume, and weight of the surgical specimen. Margin status was determined using surgical specimens only, and not intraoperative frozen sections. All cases in this series were completed using the four-arm da Vinci Robotic System (Intuitive Surgical, Sunnyvale, California). RESULTS: Sixty-one patients had prostate cancer on their final surgical pathology specimens. Pathologic stage T2 and stage T3 patients were 88.7 percent and 9.7 percent of all cases, respectively. The pathologic Gleason score was 7 or greater in 62.3 percent. Our overall positive surgical margin rate was 3.3 percent. Patients with pathologic T2 and T3 disease had a positive surgical margin rate of 1.8 percent and 16.7 percent, respectively. CONCLUSIONS: Our study suggests that RALP can have equal if not better pathologic outcomes compared to open radical prostatectomy even during the initial series of cases. We argue that the learning curve for RALP is shorter than previously thought with respect to oncologic outcomes, and concerns asserting that lack of tactile feedback leads to poor oncologic outcomes are unfounded.