Disentangling the links between gastric emptying and binge eating v. purging in eating disorders using a case-control design

BACKGROUND

Prior work supports delayed gastric emptying in anorexia nervosa and bulimia nervosa (BN) but not binge-eating disorder, suggesting that neither low body weight nor binge eating fully accounts for slowed gastric motility. Specifying a link between delayed gastric emptying and self-induced vomiting could offer new insights into the pathophysiology of purging disorder (PD).

METHODS

Women (N = 95) recruited from the community meeting criteria for DSM-5 BN who purged (n = 26), BN with nonpurging compensatory behaviors (n = 18), PD (n = 25), or healthy control women (n = 26) completed assessments of gastric emptying, gut peptides, and subjective responses over the course of a standardized test meal under two conditions administered in a double-blind, crossover sequence: placebo and 10 mg of metoclopramide.

RESULTS

Delayed gastric emptying was associated with purging with no main or moderating effects of binge eating in the placebo condition. Medication eliminated group differences in gastric emptying but did not alter group differences in reported gastrointestinal distress. Exploratory analyses revealed that medication caused increased postprandial PYY release, which predicted elevated gastrointestinal distress.

CONCLUSIONS

Delayed gastric emptying demonstrates a specific association with purging behaviors. However, correcting disruptions in gastric emptying may exacerbate disruptions in gut peptide responses specifically linked to the presence of purging after normal amounts of food.

Which Internal Medicine Clerkship Characteristics Are Associated With Students' Performance on the NBME Medicine Subject Exam? A Multi-Institutional Analysis

PURPOSE

To identify which internal medicine clerkship characteristics may relate to NBME Medicine Subject Examination scores, given the growing trend toward earlier clerkship start dates.

METHOD

The authors used linear mixed effects models (univariable and multivariable) to determine associations between medicine exam performance and clerkship characteristics (longitudinal status, clerkship length, academic start month, ambulatory clinical experience, presence of a study day, involvement in a combined clerkship, preclinical curriculum type, medicine exam timing). Additional covariates included number of NBME clinical subject exams used, number of didactic hours, use of a criterion score for passing the medicine exam, whether medicine exam performance was used to designate clerkship honors, and United States Medical Licensing Examination Step 1 performance. The sample included 24,542 examinees from 62 medical schools spanning 3 academic years (2011-2014).

RESULTS

The multivariable analysis found no significant association between clerkship length and medicine exam performance (all pairwise P > .05). However, a small number of examinees beginning their academic term in January scored marginally lower than those starting in July (P < .001). Conversely, examinees scored higher on the medicine exam later in the academic year (all pairwise P < .001). Examinees from schools that used a criterion score for passing the medicine exam also scored higher than those at schools that did not (P < .05). Step 1 performance remained positively associated with medicine exam performance even after controlling for all other variables in the model (P < .001).

CONCLUSIONS

In this sample, the authors found no association between many clerkship variables and medicine exam performance. Instead, Step 1 performance was the most powerful predictor of medicine exam performance. These findings suggest that medicine exam performance reflects the overall medical knowledge students accrue during their education rather than any specific internal medicine clerkship characteristics.

Examining weight suppression as a transdiagnostic factor influencing illness trajectory in bulimic eating disorders

Recent research indicates that weight suppression (WS: defined as the difference between highest lifetime and current weight) prospectively predicts illness trajectory across eating disorders characterized by binge eating, including AN binge-purge subtype (ANbp), bulimia nervosa (BN), and binge eating disorder (BED), collectively referred to as bulimic eating disorders. Through a series of studies, we have developed a model to explain the link between WS and illness trajectory in bulimic eating disorders. Our model posits that WS contributes to reduced circulating leptin, which leads to reduced postprandial glucagon-like peptide 1 (GLP-1) response. Diminished leptin and GLP-1 function contribute to alterations in two reward-related constructs in the Research Domain Criteria (RDoC): reward value/effort and reward satiation. Respectively, these changes increase drive/motivation to consume food and decrease ability for food consumption to lead to a state of satiation/satisfaction. Combined, these alterations increase risk for experiencing large, out-of-control binge-eating episodes. The following review presents evidence that contributed to the development of this model as well as preliminary findings from an on-going project funded to test this model.

Disturbance of gut satiety peptide in purging disorder

OBJECTIVE

Little is known about biological factors that contribute to purging after normal amounts of food-the central feature of purging disorder (PD). This study comes from a series of nested studies examining ingestive behaviors in bulimic syndromes and specifically evaluated the satiety peptide YY (PYY) and the hunger peptide ghrelin in women with PD (n = 25), bulimia nervosa-purging (BNp) (n = 26), and controls (n = 26). Based on distinct subjective responses to a fixed meal in PD (Keel, Wolfe, Liddle, DeYoung, & Jimerson, ), we tested whether postprandial PYY response was significantly greater and ghrelin levels significantly lower in women with PD compared to controls and women with BNp.

METHOD

Participants completed structured clinical interviews, self-report questionnaires, and laboratory assessments of gut peptide and subjective responses to a fixed meal.

RESULTS

Women with PD demonstrated a significantly greater postprandial PYY response compared to women with BNp and controls, who did not differ significantly. PD women also endorsed significantly greater gastrointestinal distress, and PYY predicted gastrointestinal intestinal distress. Ghrelin levels were significantly greater in PD and BNp compared to controls, but did not differ significantly between eating disorders. Women with BNp endorsed significantly greater postprandial hunger, and ghrelin predicted hunger.

DISCUSSION

PD is associated with a unique disturbance in PYY response. Findings contribute to growing evidence of physiological distinctions between PD and BNp. Future research should examine whether these distinctions account for differences in clinical presentation as this could inform the development of specific interventions for patients with PD.

Weight suppression and bulimic syndrome maintenance: Preliminary findings for the mediating role of leptin

OBJECTIVE

Longitudinal studies support a prospective relationship between weight suppression (WS) and bulimic syndrome (BN-S) maintenance. Although biobehavioral mechanisms have been proposed to explain this link, such mechanisms have yet to be identified. Given that weight loss would reduce leptin levels which may influence eating, this study examined whether reduced leptin levels mediate the link between greater WS and longer illness duration.

METHOD

Women (N = 53), ages 18-45 years, were recruited from the community if they met criteria for a BN-S, including either DSM-5 bulimia nervosa (BN; n = 33) or purging disorder (PD: n = 20), and fell within a healthy weight range (18.5-26.5 kg/m² ). Participants completed clinical assessments and provided blood samples to measure circulating leptin.

RESULTS

Significant associations were found among greater WS, lower leptin concentrations, and longer duration of illness. Mediation analyses using bootstrapping procedures indicated all paths were significant and that leptin mediated the link between WS and illness duration. An alternative model in which longer illness duration contributed to leptin, via greater WS, was not supported.

DISCUSSION

Longitudinal research is needed to support temporal associations and explore behavioral mechanisms linking leptin to illness trajectory.

HIV in older adults

The prevalence of HIV/AIDS in older adults continues to increase, and in 2005, 25% of those infected with HIV were older than 50. Successful treatment regimens allow people to live longer with HIV, but the incidence is also increasing, with older adults accounting for 15% of new HIV cases in 2005. Prevention, diagnosis, and management of HIV/AIDS in older adults are complex issues. The aging immune system may impact response to treatment with highly active antiretroviral therapy (HAART), and there is greater potential for drug-drug interactions and toxicities due to comorbidities and polypharmacy. Patients living longer with HIV are more likely to develop diseases associated with aging, and at an earlier age, than those without HIV. These include coronary artery disease, dyslipidemia, metabolic syndrome, diabetes, osteoporosis, and dementia. Geriatricians and primary care providers are increasingly responsible for managing these complex issues.

The evolution of the Fenway Community Health model

Fenway Community Health was founded by community activists in 1971 in the Fenway neighborhood of Boston, Mass, and within a decade had rapidly expanded its medical services for gay men in response to the AIDS epidemic. Increased expertise and cultural competence in lesbian, gay, bisexual, and transgender (LGBT) care led to expansion of medical services to address broader community concerns, ranging from substance use to parenting issues to domestic and homophobic violence, as well as specialized programs for lesbians, bisexuals, and transgendered individuals. Fenway began as a grassroots neighborhood clinic. In 1975, the center recorded 5000 patient care visits; in 2000, Fenway's clinical departments recorded 50,850 visits by 8361 individuals, including more than 1100 individuals receiving HIV-associated care. The center now has more than 170 staff people responsible for clinical programs, community education, research, administration, planning, and development. Over the past few years, Fenway's annual budget has exceeded $10 million. Fenway has established standards for improved cultural competence about LGBT health issues for other health providers and has developed programs to educate the general community about specific LGBT health concerns. This health center may provide a model of comprehensive LGBT health services that have a local impact.

In vivo phosphorylation of the lamin B receptor. Binding of lamin B to its nuclear membrane receptor is affected by phosphorylation

Previous studies have shown that the nuclear envelope of avian erythrocytes contains a 58-kDa integral membrane protein (p58) which serves as a receptor for the karyoskeletal protein lamin B (Worman, J. H., Yuan, J., Blobel, G., and Georgatos, S. D. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 8531-8534). We now demonstrate that p58 is phosphorylated in vivo at serine residues and that its phosphorylation is stimulated by isoproterenol in a dose-dependent fashion. We further show that dephosphorylation of p58 reduces significantly its binding to lamin B. These data suggest that phosphorylation may constitute one of the major mechanisms regulating the lamina-nuclear membrane interactions.

Pericarotid cluster headache

Cluster headache is generally not associated with recognised disease, and the pathogenesis remains unclear. The onset of typical cluster headaches is reported in a patient with nasopharyngeal carcinoma. The tumor encircled the internal carotid artery but did not extend intracranially. It thus appears possible that cluster headaches may be triggered by processes involving the carotid artery.

Inhibition of growth of mouse ehrlich ascites by normal tissue extracts

A dialyzable component from the aqueous extracts of mouse skeletal muscle and liver inhibited in vitro growth of a mouse Ehrlich ascites. A similar component was not detected in extracts of spleen, kidney, lung, skin, serum or small intestine. The muscle component appeared to be different from that of the liver in its resistance to heat and its stability in the culture medium. Both components however were stable on storage at 4, 23 and 37 degrees C for 72 h. Intraperitoneal injection of the muscle and liver component into mice previously innoculated with Ehrlich ascites significantly decreased tumor incidence in these animals as compared with the control.

Enolase catalyzed beta,gamma-alpha,beta isomerization of 2-phospho-3-butenoic acid to (Z)-phosphoenol-alpha-ketobutyrate

2-Phospho-3-butenoic acid was synthesized and found to be a substrate for both yeast and rabbit muscle enolase (EC 4.2.1.11). Enolase catalyzes the isomerization of 2-phospho-3-butenoic acid to (Z)-phosphoenol-alpha-ketobutyrate, a beta,gamma-alpha,beta isomerization. Nuclear magnetic resonance studies on the product indicate only one isomer is formed. This reaction provides indirect evidence in further support of a carbanion intermediate for the enolase reaction. 2-Phospho-3-butenoic acid is also a good competitive inhibitor of both yeast and rabbit muscle pyruvate kinase (EC 2.7.1.40).