GOG 244-The lymphedema and gynecologic cancer (LEG) study: Incidence and risk factors in newly diagnosed patients

© 2019 Elsevier Inc. Objectives: To evaluate the incidence and risk factors for lymphedema associated with surgery for gynecologic malignancies on GOG study 244. Methods: Women undergoing a lymph node dissection for endometrial, cervical, or vulvar cancer were eligible for enrollment. Leg volume was calculated from measurements at 10-cm intervals starting 10 cm above the bottom of the heel to the inguinal crease. Measurements were obtained preoperatively and postoperatively at 4–6 weeks, and at 3-, 6-, 9-, 12-, 18-, and 24- months. Lymphedema was defined as a limb volume change (LVC) ≥10% from baseline and categorized as mild: 10–19% LVC; moderate: 20–40% LVC; or severe: \u3e40% LVC. Risk factors associated with lymphedema were also analyzed. Results: Of 1054 women enrolled on study, 140 were inevaluable due to inadequate measurements or eligibility criteria. This left 734 endometrial, 138 cervical, and 42 vulvar patients evaluable for LVC assessment. Median age was 61 years (range, 28–91) in the endometrial, 44 years (range, 25–83) in the cervical, and 58 years (range, 35–88) in the vulvar group. The incidence of LVC ≥10% was 34% (n = 247), 35% (n = 48), and 43% (n = 18), respectively. The peak incidence of lymphedema was at the 4–6 week assessment. Logistic regression analysis showed a decreased risk with advanced age (p = 0.0467). An exploratory analysis in the endometrial cohort showed an increased risk with a node count \u3e8 (p = 0.033). Conclusions: For a gynecologic cancer, LVC decreased with age greater than 65, but increased with a lymph node count greater than 8 in the endometrial cohort. There was no association with radiation or other risk factors

A Mismatch-Based Model for Memory Reconsolidation and Extinction in Attractor Networks

The processes of memory reconsolidation and extinction have received increasing attention in recent experimental research, as their potential clinical applications begin to be uncovered. A number of studies suggest that amnestic drugs injected after reexposure to a learning context can disrupt either of the two processes, depending on the behavioral protocol employed. Hypothesizing that reconsolidation represents updating of a memory trace in the hippocampus, while extinction represents formation of a new trace, we have built a neural network model in which either simple retrieval, reconsolidation or extinction of a stored attractor can occur upon contextual reexposure, depending on the similarity between the representations of the original learning and reexposure sessions. This is achieved by assuming that independent mechanisms mediate Hebbian-like synaptic strengthening and mismatch-driven labilization of synaptic changes, with protein synthesis inhibition preferentially affecting the former. Our framework provides a unified mechanistic explanation for experimental data showing (a) the effect of reexposure duration on the occurrence of reconsolidation or extinction and (b) the requirement of memory updating during reexposure to drive reconsolidation

Molecular Constraints on Synaptic Tagging and Maintenance of Long-Term Potentiation: A Predictive Model

Protein synthesis-dependent, late long-term potentiation (LTP) and depression (LTD) at glutamatergic hippocampal synapses are well characterized examples of long-term synaptic plasticity. Persistent increased activity of the enzyme protein kinase M (PKM) is thought essential for maintaining LTP. Additional spatial and temporal features that govern LTP and LTD induction are embodied in the synaptic tagging and capture (STC) and cross capture hypotheses. Only synapses that have been "tagged" by an stimulus sufficient for LTP and learning can "capture" PKM. A model was developed to simulate the dynamics of key molecules required for LTP and LTD. The model concisely represents relationships between tagging, capture, LTD, and LTP maintenance. The model successfully simulated LTP maintained by persistent synaptic PKM, STC, LTD, and cross capture, and makes testable predictions concerning the dynamics of PKM. The maintenance of LTP, and consequently of at least some forms of long-term memory, is predicted to require continual positive feedback in which PKM enhances its own synthesis only at potentiated synapses. This feedback underlies bistability in the activity of PKM. Second, cross capture requires the induction of LTD to induce dendritic PKM synthesis, although this may require tagging of a nearby synapse for LTP. The model also simulates the effects of PKM inhibition, and makes additional predictions for the dynamics of CaM kinases. Experiments testing the above predictions would significantly advance the understanding of memory maintenance.Comment: v3. Minor text edits to reflect published versio

Gynecologic Oncology

0S115-S116125, Supplement