The microdynamics of spatial polarization: A model and an application to survey data from Ukraine.

Although spatial polarization of attitudes is extremely common around the world, we understand little about the mechanisms through which polarization on divisive issues rises and falls over time. We develop a theory that explains how political shocks can have different effects in different regions of a country depending upon local dynamics generated by the preexisting spatial distribution of attitudes and discussion networks. Where opinions were previously divided, attitudinal diversity is likely to persist after the shock. Meanwhile, where a clear precrisis majority exists on key issues, opinions should change in the direction of the predominant view. These dynamics result in greater local homogeneity in attitudes but at the same time exacerbate geographic polarization across regions and sometimes even within regions. We illustrate our theory by developing a modified version of the adaptive voter model, an adaptive network model of opinion dynamics, to study changes in attitudes toward the European Union (EU) in Ukraine in the context of the Euromaidan Revolution of 2013 to 2014. Using individual-level panel data from surveys fielded before and after the Euromaidan Revolution, we show that EU support increased in areas with high prior public support for EU integration but declined further where initial public attitudes were opposed to the EU, thereby increasing the spatial polarization of EU attitudes in Ukraine. Our tests suggest that the predictive power of both network and regression models increases significantly when we incorporate information about the geographic location of network participants, which highlights the importance of spatially rooted social networks.

UTILITY OF A GLUCOCORTICOID SPARING STRATEGY IN THE MANAGEMENT OF PATIENTS FOLLOWING TRANSSPHENOIDAL SURGERY.

OBJECTIVE: Following transsphenoidal surgery (TSS), it is important to assess for and manage adrenal insufficiency (AI). The goal of this study is to assess the efficacy and safety of a glucocorticoid (GC) sparing protocol to limit GC exposure in patients undergoing TSS. METHODS: Adult patients undergoing TSS (excluding Cushing disease) with adequate adrenal function prior to surgery underwent TSS without perioperative GC coverage. Following TSS, daily morning fasting serum cortisol levels were tested. GCs were administered at stress doses for serum cortisol <5 mcg/dL, between 5 and 12 mcg/dL in the presence of clinically significant symptoms of AI, or >12 mcg/dL with severe headache, nausea or vomiting, fatigue, anorexia, or hyponatremia. The primary endpoint was the use of GCs in the immediate postoperative period. RESULTS: Of 178 subjects, GCs were administered to 80 (45%) patients for the following indications: 31.3% for serum cortisol <5 mcg/dL; 36.3% for cortisol between 5 and 12 mcg/dL accompanied by symptoms or signs of AI; 8.8% for moderate to severe postoperative hyponatremia; and 7.5% for severe headache, nausea and vomiting, fatigue, or anorexia with cortisol >12 mcg/dL. Logistic regression analysis showed that longer length of hospital stay (odds ratio [OR] 1.22, confidence interval [CI] 1.02-1.45) and the presence of new postoperative anterior pituitary hormone deficiency (OR 3.3, CI 1.26-8.67) were associated with postoperative GC use. By 12 weeks, only 14% of subjects remained on GCs. There were no adverse events related to withholding GCs. CONCLUSION: Our protocol for managing GC replacement is both safe and effective for limiting GC exposure in patients undergoing TSS. ABBREVIATIONS: AI = adrenal insufficiency CI = confidence interval FSH = follicle-stimulating hormone GC = glucocorticoid GH = growth hormone IGF-1 = insulin-like growth factor-1 IV = intravenous LH = luteinizing hormone LOS = length of hospital stay OR = odds ratio TSS = transsphenoidal surgery.

Utility of Adrenocorticotropic Hormone in Assessing the Response to Transsphenoidal Surgery for Cushing's Disease.

OBJECTIVES: To compare adrenocorticotrophic hormone (ACTH) and cortisol dynamics in subjects with Cushing's disease (CD) following transsphenoidal surgery (TSS) and to determine the value of early postoperative ACTH levels in predicting subsequent hypocortisolemia. METHODS: Following TSS for CD, serum cortisol and plasma ACTH were measured every 6 hours in the absence of empiric glucocorticoid coverage. RESULTS: A total of 26 subjects (25 female) underwent 28 operations. Hypocortisolemia was achieved in 21 (81%) subjects after the initial TSS. Repeat TSS was performed in 2 subjects, resulting in hypocortisolemia in 1. Subjects who achieved hypocortisolemia had significantly lower ACTH levels by 19 hours postoperatively (P = .007). Plasma ACTH fell to <30 pg/mL in 86% and <20 pg/mL in 82% of subjects who subsequently achieved hypocortisolemia. Plasma ACTH declined to <30 pg/mL by a mean of 10 hours and to <20 pg/mL by 13 hours prior to hypocortisolemia. Follow-up data were available on 25 patients for a median of 23 months. Three subjects who achieved initial surgical remission had disease recurrence at 19, 24, and 36 months; all of these subjects had a postoperative nadir serum cortisol levels <3 µg/dL and plasma ACTH <20 pg/mL. CONCLUSION: Following TSS for CD, plasma ACTH declined prior to achievement of hypocortisolemia in most subjects. In the majority, the ACTH level reached a nadir of <20 pg/mL. Low early postoperative ACTH levels predict early hypocortisolemia but may not accurately predict long-term remission.

Patient and caregiver perspectives of fluid discharge protocols following pituitary surgery.

Background: Post-operative fluid restriction after transsphenoidal surgery (TSS) for pituitary tumors may effectively prevent delayed hyponatremia, the most common cause of readmission. However, implementation of individualized fluid restriction interventions after discharge is often complex and poses challenges for provider and patient. The purpose of this study was to understand the factors necessary for successful implementation of fluid restriction and discharge care protocols following TSS. Methods: Semi-structured interviews with fifteen patients and four caregivers on fluid discharge protocols were conducted following TSS. Patients and caregivers who had surgery before and after the implementation of updated discharge protocols were interviewed. Data were analyzed inductively using a procedure informed by rapid and thematic analysis. Results: Most patients and caregivers perceived fluid restriction protocols as acceptable and feasible when indicated. Facilitators to the protocols included clear communication about the purpose of and strategies for fluid restriction, access to the care team, and involvement of patients' caregivers in care discussions. Barriers included patient confusion about differences in the care plan between teams, physical discomfort of fluid restriction, increased burden of tracking fluids during recovery, and lack of clarity surrounding desmopressin prescriptions. Conclusion: Outpatient fluid restriction protocols are a feasible intervention following pituitary surgery but requires frequent patient communication and education. This evaluation highlights the importance of patient engagement and feedback to effectively develop and implement complex clinical interventions.

Clinical characteristics, timing of peak responses and safety aspects of two dosing regimens of the glucagon stimulation test in evaluating growth hormone and cortisol secretion in adults.

Weight-based (WB: 0.03 mg/kg) and fixed dose (FD: 1-1.5 mg) regimens of the glucagon stimulation test (GST) have been used to evaluate GH and cortisol secretion in children and adults, respectively. However, experience of the WB regimen in assessing GH and cortisol secretion in adults are limited. We describe a multicenter experience using WB and FD regimens in evaluating GH and cortisol secretion in adults suspected of GH deficiency and central adrenal insufficiency. Retrospective case series of GSTs (n = 515) performed at five tertiary centers. Peak and nadir glucose, and peak GH and peak cortisol responses occurred later with WB (mean dose: 2.77 mg) compared to FD (mean dose: 1.20 mg) regimens. Main side-effects were nausea and vomiting, particularly in younger females. Nausea was comparable but vomiting was more frequent in the WB regimen (WB: 10.0 % vs FD: 2.4 %; P < 0.05). Peak and nadir glucose, ΔGH, and peak and Δcortisol were higher in the WB regimen. In both regimens, age correlated negatively with peak cortisol levels, and body mass index (BMI), fasting, peak and nadir glucose correlated negatively with peak GH levels. WB and FD regimens can induce adult GH and cortisol secretion, but peak responses occur later in the WB regimen. Both regimens are relatively safe, and vomiting was more prevalent in the WB regimen. As age, BMI, and glucose tolerance negatively correlated with peak GH and cortisol levels, the WB regimen may be more effective than the FD regimen in older overweight glucose intolerant patients.

Inconsistent vs consistent right-handers' performance on an episodic memory task: evidence from the California Verbal Learning Test.

Inconsistent handedness is associated with better memory performance on episodic memory tasks than consistent handedness. The present study further explored this difference in memory related to handedness by administering a measure that is used in clinical settings to assess different aspects of long-term memory. The results indicated that inconsistent right-handed individuals recalled and recognised more words on the California Verbal Learning Test-II than consistent right-handed individuals. Inconsistent right-handers also showed better performance than consistent right-handers on measures of source recognition. The results of this study further extend the effects of handedness on memory to the clinical setting because the CVLT-II is a measure used extensively in clinical neuropsychology.

The dynamics of post-operative plasma ACTH values following transsphenoidal surgery for Cushing's disease.

Rapid assessment of adrenal function is critical following transsphenoidal surgery (TSS) for Cushing's disease (CD) in order to determine surgical efficacy. We hypothesize that there may be a role for ACTH measurement as a rapid indicator of adrenal function. Following surgery for CD, glucocorticoids were withheld and paired plasma ACTH and serum cortisol levels were measured every 6 h. Post-operative hypocortisolemia was defined as serum cortisol <2 mcg/dl or a serum cortisol <5 mcg/dl with the onset of symptoms of adrenal insufficiency within 72 h. We studied 12 subjects, all female, mean age 44.6 years (range 25-55), including 13 surgeries: nine subjects attained hypocortisolemia. Plasma ACTH levels decreased more in subjects with hypocortisolemia (0.9 pg/ml/hr, P = 0.0028) versus those with persistent disease (0 0.2 pg/ml/hr, P = 0.26) within the first 48 h after surgery. In contrast to subjects with persistent disease, all subjects with hypocortisolemia achieved a plasma ACTH <20 pg/ml by 19 h (range 1-19 h). Four of the nine subjects with hypocortisolemia achieved plasma ACTH <20 pg/ml by 13 h and the remaining five subjects by 19 h. Hypocortisolemia occurred between 3-36 h following achievement of a plasma ACTH <20 pg/ml. In CD, a reduction in postoperative plasma ACTH levels differentiates subjects with surgical remission versus subjects with persistent disease. The utility of plasma ACTH measurements in the postoperative management of CD remains to be determined.