Sunnybrook Health Sciences Centre

About: Sunnybrook Health Sciences Centre is a healthcare organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Breast cancer. The organization has 7689 authors who have published 15236 publications receiving 523019 citations. The organization is also known as: Sunnybrook.

Implications on clinical scenario of gold nanoparticle radiosensitization in regards to photon energy, nanoparticle size, concentration and location

Abstract: Gold nanoparticle (AuNP) radiosensitization represents a novel approach to enhance the effectiveness of ionizing radiation. Its efficiency varies widely with photon source energy and AuNP size, concentration, and intracellular localization. In this Monte Carlo study we explored the effects of those parameters to define the optimal clinical use of AuNPs. Photon sources included (103)Pd and (125)I brachytherapy seeds; (169)Yb, (192)Ir high dose rate sources, and external beam sources 300 kVp and 6 MV. AuNP sizes were 1.9, 5, 30, and 100 nm. We observed a 10(3) increase in the rate of photoelectric absorption using (125)I compared to 6 MV. For a (125)I source, to double the dose requires concentrations of 5.33-6.26 mg g(-1) of Au or 7.10 × 10(4) 30 nm AuNPs per tumor cell. For 6 MV, concentrations of 1560-1760 mg g(-1) or 2.17 × 10(7) 30 nm AuNPs per cell are needed, which is not clinically achievable. Examining the proportion of energy transferred to escaping particles or internally absorbed in the nanoparticle suggests two clinical strategies: the first uses photon energies below the k-edge and takes advantage of the extremely localized Auger cascade. It requires small AuNPs conjugated to tumor targeted moieties and nuclear localizing sequences. The second, using photon sources above the k-edge, requires a higher gold concentration in the tumor region. In this approach, energy deposited by photoelectrons is the main contribution to radiosensitization; AuNP size and cellular localization are less relevant.

The Surgical Management of Small Bowel Neuroendocrine Tumors: Consensus Guidelines of the North American Neuroendocrine Tumor Society.

Abstract: Small bowel neuroendocrine tumors (SBNETs) have been increasing in frequency over the past decades, and are now the most common type of small bowel tumor. Consequently, general surgeons and surgical oncologists are seeing more patients with SBNETs in their practices than ever before. The management of these patients is often complex, owing to their secretion of hormones, frequent presentation with advanced disease, and difficulties with making the diagnosis of SBNETs. Despite these issues, even patients with advanced disease can have long-term survival. There are a number of scenarios which commonly arise in SBNET patients where it is difficult to determine the optimal management from the published data. To address these challenges for clinicians, a consensus conference was held assembling experts in the field to review and discuss the available literature and patterns of practice pertaining to specific management issues. This paper summarizes the important elements from these studies and the recommendations of the group for these questions regarding the management of SBNET patients.

Primer on medical decision analysis: Part 1--Getting started.

Abstract: This paper is Part 1 of a five-part series covering practical issues in the performance of decision analysis. The intended audience is individuals who are learning how to perform decision analyses, not just read them. The series assumes familiarity with the basic concepts of decision analysis. It imparts many of the recommendations the authors have learned in teaching a one-semester course in decision analysis to graduate students. Part 1 introduces the topic and covers questions such as choosing an appropriate question, determining the tradeoff between accuracy and simplicity, and deciding on a time frame.

Are activity-based assessments of balance and gait in the elderly predictive of risk of falling and/or type of fall?

Abstract: OBJECTIVE: To determine whether an activity-based test of balance and gait is predictive of the risk of: (1) falling in situations that are related to specific tasks evaluated as part of the test, (2) experiencing falls precipitated by different classes of biomechanical events, or (3) falling in general; and to compare the predictive ability of the activity-based test for the falls described in (2) and (3) to that of a posturography test that has been found previously to be predictive of falling risk. DESIGN: Cohort study. SETTING: Baseline tests performed in balance laboratory; subsequent history of falling monitored prospectively for 1 year in two residential-care facilities. PARTICIPANTS: Seventeen male and 83 female consecutive volunteers (mean age = 83, SD = 6) who were independent in activities of daily living and able to stand unaided. MEASUREMENTS: Independent variables were derived from an activity-based balance-and-gait test and a posturography test. Dependent variables were the numbers of subjects with one or more: (1) falls in specific situations related to activity-based test items, (2) falls related to general classes of biomechanical precipitant, and (3) falls in general. MAIN RESULTS: Subjects who were rated as "abnormal" in activity-based test items related to transfers, turning or reaching were more likely to experience one or more falls in related situations in everyday life. Activity-based scores were predictive of risk of experiencing falls with no obvious biomechanical precipitant and falls precipitated by center-of-mass perturbation, but not falls precipitated by base-of-support perturbation. In comparison, a posturographic measure of spontaneous medial-lateral postural sway (blindfolded conditions) failed to predict falls having no biomechanical precipitant, but provided the best predictions of both center-of-mass and base-of-support falls, as well as risk of falling in general. CONCLUSIONS: Activity-based testing of certain tasks (transfer, turning, reaching) may be useful in indicating a specific need for intervention to reduce the risk of falling during related everyday activities. In terms of predicting falling risk, a static posturography test may provide better prediction overall of the different classes of falls and may be useful as a quick and simple screening tool to help identify high-risk individuals. Language: en

Measuring diaphragm thickness with ultrasound in mechanically ventilated patients: feasibility, reproducibility and validity

Abstract: Ultrasound measurements of diaphragm thickness (T di) and thickening (TFdi) may be useful to monitor diaphragm activity and detect diaphragm atrophy in mechanically ventilated patients We aimed to establish the reproducibility of measurements in ventilated patients and determine whether passive inflation by the ventilator might cause thickening apart from inspiratory effort Five observers measured T di and TFdi in 96 mechanically ventilated patients The probe site was marked in 66 of the 96 patients TFdi was measured at peak and end-inspiration (airway occluded and diaphragm relaxed) in nine healthy volunteers inhaling to varying lung volumes The association with diaphragm electrical activity was quantified Right hemidiaphragm thickness was obtained on 95 % of attempts; left hemidiaphragm measurements could not be obtained consistently Right hemidiaphragm thickness measurements were highly reproducible (mean ± SD 24 ± 08 mm, repeatability coefficient 02 mm, reproducibility coefficient 04 mm), particularly after marking the location of the probe TFdi measurements were only moderately reproducible (median 11 %, IQR 3–17 %, repeatability coefficient 17 %, reproducibility coefficient 16 %) TFdi and diaphragm electrical activity were positively correlated, r 2 = 032, p < 001) At inspiratory volumes below 50 % of inspiratory capacity, passive inflation did not cause diaphragm thickening TFdi was considerably lower in patients on either partially assisted or controlled ventilation compared to healthy subjects (median 11 vs 35 %, p < 0001) Ultrasound measurements of right hemidiaphragm thickness are feasible and highly reproducible in ventilated patients At clinically relevant inspiratory volumes, diaphragm thickening reflects muscular contraction and not passive inflation This technique can be reliably employed to monitor diaphragm thickness, activity, and function during mechanical ventilation