"You See Yourself Like in a Mirror": The Effects of Internet-Mediated Personal Networks on Body Image and Eating Disorders.

Body image issues associated with eating disorders involve attitudinal and perceptual components: individuals' dissatisfaction with body shape or weight, and inability to assess body size correctly. While prior research has mainly explored social pressures produced by the media, fashion, and advertising industries, this paper focuses on the effects of personal networks on body image, particularly in the context of internet communities. We use data collected on a sample of participants to websites on eating disorders, and map their personal networks. We specify and estimate a model for the joint distribution of attitudinal and perceptual components of body image as a function of network-related characteristics and attributional factors. Supported by information gathered through in-depth interviews, the empirical estimates provide evidence that personal networks can be conducive to positive body image development, and that the influence of personal networks varies significantly by body size. We situate our discussion in current debates about the effects of computer-mediated and face-to-face communication networks on eating disorders and related behaviors.

Determinants of knowledge-sharing networks in primary care.

BACKGROUND: Around the world, health reforms are increasingly fostering collaboration and integration among primary care physicians with the aim of facilitating knowledge sharing and evidence-informed decision-making. Although extant research on this topic is abundant, the evidence and results regarding social and organizational factors affecting the formation of knowledge-sharing networks in this setting are inconclusive. PURPOSE: The aim of this article is to explore multiple theoretical mechanisms explaining the formation of knowledge-sharing networks among primary care physicians across relevant clinical areas. METHODOLOGY/APPROACH: The data are collected from two local health authorities in the Italian National Health Service that are responsible for delivering primary care in two Italian regions. Exponential random graph models are used to test the hypotheses. FINDINGS: Our findings indicate that knowledge-sharing networks are highly correlated across clinical areas. In addition, knowledge-sharing networks are highly reciprocal and clustered. We also observe that formal models adopted to foster collaboration have remarkably different effects on the formation of knowledge networks, depending upon the diverse knowledge management approaches adopted in the surveyed local health authorities. PRACTICE IMPLICATIONS: Primary care organizations need to develop and implement knowledge management practices in order to help physicians in identifying knowledge domain experts as well as to support connections through formal groupings and incentives.

Bayesian exponential random graph modelling of interhospital patient referral networks.

Using original data that we have collected on referral relations between 110 hospitals serving a large regional community, we show how recently derived Bayesian exponential random graph models may be adopted to illuminate core empirical issues in research on relational coordination among healthcare organisations. We show how a rigorous Bayesian computation approach supports a fully probabilistic analytical framework that alleviates well-known problems in the estimation of model parameters of exponential random graph models. We also show how the main structural features of interhospital patient referral networks that prior studies have described can be reproduced with accuracy by specifying the system of local dependencies that produce - but at the same time are induced by - decentralised collaborative arrangements between hospitals. Copyright © 2017 John Wiley & Sons, Ltd.

Relational event models for longitudinal network data with an application to interhospital patient transfers.

The main objective of this paper is to introduce and illustrate relational event models, a new class of statistical models for the analysis of time-stamped data with complex temporal and relational dependencies. We outline the main differences between recently proposed relational event models and more conventional network models based on the graph-theoretic formalism typically adopted in empirical studies of social networks. Our main contribution involves the definition and implementation of a marked point process extension of currently available models. According to this approach, the sequence of events of interest is decomposed into two components: (a) event time and (b) event destination. This decomposition transforms the problem of selection of event destination in relational event models into a conditional multinomial logistic regression problem. The main advantages of this formulation are the possibility of controlling for the effect of event-specific data and a significant reduction in the estimation time of currently available relational event models. We demonstrate the empirical value of the model in an analysis of interhospital patient transfers within a regional community of health care organizations. We conclude with a discussion of how the models we presented help to overcome some the limitations of statistical models for networks that are currently available. Copyright © 2017 John Wiley & Sons, Ltd.

A New Reliable Method for Evaluating Gallbladder Dynamics: The 3-Dimensional Sonographic Examination.

OBJECTIVES: The purpose of this study was to compare conventional 2-dimensional (2D) B-mode sonography with 3-dimensional (3D) sonography for assessing gallbladder volume and contractility. METHODS: Gallbladder volume and contractility were evaluated in 32 healthy volunteers after fasting and abstinence from smoking for 8 hours and after a standardized balanced liquid meal. The gallbladder was evaluated with 2D sonography (with the use of the ellipsoid method) and with 3D sonography using a volumetric matrix probe. Both measurements were made by an operator who was skilled in sonography and an unskilled operator. The group of volunteers was subdivided into 2 subgroups including 16 participants, which represented the "2 moments" of acquisition by the techniques, particularly for the unskilled operator. RESULTS: The postprandial volumes obtained with 3D sonography were significantly lower in comparison to the volumes obtained with 2D sonography (P= .013), and there was a significant difference between the measurements made by the skilled and unskilled operators only for 2D sonography (P< .001), whereas between the 2 moments of acquisition by the 3D technique, there was no significant difference. The reproducibility of the technique for evaluation of gallbladder volumes was higher for 3D sonography than 2D sonography, particularly for the postprandial evaluation. CONCLUSIONS: The new 3D sonographic method using a volumetric matrix probe is a simple, reliable, and more reproducible technique than conventional 2D sonography, even if performed by an unskilled operator, and it allows a reliable stimulation test for a gallbladder dynamic study.

Salmonella gastroenteritis during childhood is a risk factor for irritable bowel syndrome in adulthood.

BACKGROUND & AIMS: Acute infectious gastroenteritis increases the risk for irritable bowel syndrome (IBS) and functional dyspepsia (FD). Children are particularly vulnerable to gastroenteritis because of the immaturity of their intestinal barrier, enteric nervous system, and immune response to pathogens. We investigated whether acute gastroenteritis in early life increases the risk of IBS and FD throughout adulthood. METHODS: In 1994, we identified and monitored a single culture-proven foodborne Salmonella enteritidis outbreak that involved 1811 patients (mostly pediatric) in Bologna, Italy. Clinical data were collected and a prospective, controlled, cohort study was designed. Long-term effects were assessed by mailing a questionnaire to 757 subjects 16 years after the outbreak (when all of the children were adults). We randomly selected a cohort of 250 adults exposed to Salmonella as children, all 127 individuals exposed as adults, and a cohort of nonexposed participants matched for number, age, sex, and area of residence (controls). RESULTS: Among 198 exposed participants, 64 reported FD (32.3%), compared with 51 of 188 controls (27.1%; P = .268). Among 204 exposed participants, 75 reported having IBS (36.8%) compared with 44 of 189 controls (23.3%; P = .004). The odds ratio for IBS among people exposed to the Salmonella was 1.92 (95% confidence interval: 1.23-2.98). The prevalence of IBS was higher in individuals exposed Salmonella as children than in controls (35.3% vs 20.5%; P = .008), but not in individuals exposed as adults, compared with controls. After multivariate logistic regression, post-infectious IBS was independently associated with anxiety and FD. CONCLUSIONS: Based on data collected from a single culture-proven foodborne Salmonella enteritidis outbreak in 1994, Salmonella-induced gastroenteritis during childhood (but not adulthood) is a risk factor for IBS.

Quality of care and interhospital collaboration: a study of patient transfers in Italy.

OBJECTIVES: We examine the dynamics of patient-sharing relations within an Italian regional community of 35 hospitals serving approximately 1,300,000 people. We test whether interorganizational relations provide individual patients access to higher quality providers of care. RESEARCH DESIGN AND METHODS: We reconstruct the complete temporal sequence of the 3461 consecutive interhospital patient-sharing events observed between each pair of hospitals in the community during 2005-2008. We distinguish between transfers occurring between and within different medical specialties. We estimate newly derived models for relational event sequences that allow us to control for the most common forms of network-like dependencies that are known to characterize collaborative relations between hospitals. We use 45-day risk-adjusted readmission rate as a proxy for hospital quality. RESULTS: After controls (eg, geographical distance, size, and the existence of prior collaborative relations), we find that patients flow from less to more capable hospitals. We show that this result holds for patient being shared both between as well as within medical specialties. Nonetheless there are strong and persistent other organizational and relational effects driving transfers. CONCLUSIONS: Decentralized patient-sharing decisions taken by the 35 hospitals give rise to a system of collaborative interorganizational arrangements that allow the patient to access hospitals delivering a higher quality of care. This result is relevant for health care policy because it suggests that collaborative relations between hospitals may produce desirable outcomes both for individual patients, and for regional health care systems.

Network approaches and interventions in healthcare settings: A systematic scoping review.

INTRODUCTION: The growing interest in networks of interactions is sustained by the conviction that they can be leveraged to improve the quality and efficiency of healthcare delivery systems. Evidence in support of this conviction, however, is mostly based on descriptive studies. Systematic evaluation of the outcomes of network interventions in healthcare settings is still wanting. Despite the proliferation of studies based on Social Network Analysis (SNA) tools and techniques, we still know little about how intervention programs aimed at altering existing patterns of social interaction among healthcare providers affect the quality of service delivery. We update and extend prior reviews by providing a comprehensive assessment of available evidence. METHODS AND FINDINGS: We searched eight databases to identify papers using SNA in healthcare settings published between 1st January 2010 and 1st May 2022. We followed Chambers et al.'s (2012) approach, using a Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. We distinguished between studies relying on SNA as part of an intervention program, and studies using SNA for descriptive purposes only. We further distinguished studies recommending a possible SNA-based intervention. We restricted our focus on SNA performed on networks among healthcare professionals (e.g., doctors, nurses, etc.) in any healthcare setting (e.g., hospitals, primary care, etc.). Our final review included 102 papers. The majority of the papers used SNA for descriptive purposes only. Only four studies adopted SNA as an intervention tool, and measured outcome variables. CONCLUSIONS: We found little evidence for SNA-based intervention programs in healthcare settings. We discuss the reasons and challenges, and identify the main component elements of a network intervention plan. Future research should seek to evaluate the long-term role of SNA in changing practices, policies and behaviors, and provide evidence of how these changes affect patients and the quality of service delivery.

Postinfectious irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by abdominal pain and changes in bowel habits, not sustained by structural changes. There is now consistent evidence indicating that IBS may be the adverse outcome of an acute episode of infectious gastroenteritis, the so-called postinfectious (PI) IBS. The infectious agents involved in the development of PI-IBS include pathogenic bacteria, parasites, and viruses. Abdominal pain and diarrhea are the most common symptoms of PI-IBS. Several studies identified a number of risk factors increasing the susceptibility for PI-IBS development. These include the virulence of the pathogen, the severity, and duration of the acute enteritis, younger age, female sex, and psychological disturbances. Several mucosal abnormalities in the colon or ileum of patients who develop PI-IBS have been described. These changes include increased mucosal permeability, an increased amount of intraepithelial lymphocytes, lamina propria T cells, and mast cells, as well as serotonin-containing enteroendocrine cells. The mediators released by these activated cells may evoke enteric nervous system responses, excite sensory afferent pathways, and induce visceral hyperalgesia. Little is known about the prognosis of PI-IBS, although it is likely better than that of nonspecific IBS. There is little evidence about a specific treatment for PI-IBS. Although probiotics and antibiotics may be promising in the prevention of PI-IBS, the efficacy of these treatments should be assessed in an ad hoc designed study.

Probiotics and irritable bowel syndrome: rationale and clinical evidence for their use.

Growing evidence suggests a potential role of intestinal microbiota in irritable bowel syndrome (IBS) pathophysiology and symptom generation. Earlier studies based on classic microbiologic techniques hypothesized the presence of qualitative changes in intestinal microbiota in IBS patients. Recently, studies with molecular techniques have provided evidence of significant changes in microbial profiles in IBS and that the composition may be correlated with certain symptoms reported by patients. Although these studies are far from being exhaustive and conclusive they provide promising results that deserve further investigation. In addition, initial evidence indicated the presence of increased amounts of bacteria in the upper small intestine of IBS patients, a condition know as small intestinal bacterial overgrowth. However, the results of these studies have provided contradictory results suggesting that this area requires further work. These qualitative and quantitative changes in intestinal microbiota may induce different effects on the intestinal mucosa including mucosal barrier defects and immune activation which may contribute to symptom generation. Studies in IBS patients have attempted to target changes in intestinal microflora with different therapeutic approaches, such as the use of prebiotics, probiotics, synbiotics, and nonabsorbable and systemic antibiotics. Overall, the results obtained in probiotic clinical trials suggest some beneficial effect over placebo in the relief of IBS symptoms. However, these results, although encouraging, should be confirmed in larger well-designed, placebo-controlled studies. A number of open questions remain to be addressed, including the dose, type, and time of administration of probiotics.

Chronic intestinal pseudo-obstruction.

Chronic intestinal pseudo-obstruction (CIPO) is a severe digestive syndrome characterized by derangement of gut propulsive motility which resembles mechanical obstruction, in the absence of any obstructive process. Although uncommon in clinical practice, this syndrome represents one of the main causes of intestinal failure and is characterized by high morbidity and mortality. It may be idiopathic or secondary to a variety of diseases. Most cases are sporadic, even though familial forms with either dominant or recessive autosomal inheritance have been described. Based on histological features intestinal pseudo-obstruction can be classified into three main categories: neuropathies, mesenchymopathies, and myopathies, according on the predominant involvement of enteric neurones, interstitial cells of Cajal or smooth muscle cells, respectively. Treatment of intestinal pseudo-obstruction involves nutritional, pharmacological and surgical therapies, but it is often unsatisfactory and the long-term outcome is generally poor in the majority of cases.

Investigating the Temporal Dynamics of Interorganizational Exchange: Patient Transfers among Italian Hospitals.

Previous research on interaction behavior among organizations (resource exchange, collaboration, communication) has typically aggregated those behaviors over time as a network of organizational relationships. The authors instead study structural-temporal patterns in organizational exchange, focusing on the dynamics of reciprocation. Applying this lens to a community of Italian hospitals during 2003-7, the authors observe two mechanisms of interorganizational reciprocation: organizational embedding and resource dependence. The authors show how these two mechanisms operate on distinct time horizons: dependence applies to contemporaneous exchange structures, whereas embedding develops through longer-term historical patterns. They also show how these processes operate differently in competitive and non-competitive contexts, operationalized in terms of market differentiation and geographic space. In noncompetitive contexts, the authors observe both logics of reciprocation, dependence in the short term and embedding over the long term, developing into population-level generalized exchange. In competitive contexts, they find no reciprocation and instead observe the microfoundations of status hierarchies.

Antiflagellin antibodies suggest infective participation in irritable bowel syndrome pathogenesis.

Irritable bowel syndrome (IBS) is a functional disorder of multifactorial origin. Recent attention has been paid to the potential role of immune activation in intestinal sensorimotor dysfunction and symptom generation in patients with IBS. The link between immune activation and IBS is further supported by the evidence that IBS may develop after an acute episode of infectious gastroenteritis, IBS-like symptoms may precede the diagnosis or accompany a period of remission of inflammatory bowel disease (IBD), and quantitative histopathologic data demonstrate the presence of low-grade mucosal immune infiltration in a large subset of patients with IBS. These data also suggest some areas of potential overlap between IBS and IBD. The present study explored the possibility that, similarly to IBD patients, IBS patients have antibodies directed against certain components of indigenous flora, such as flagellin (the primary structural component of bacterial flagella). The authors demonstrated that, compared with healthy controls, antibodies against flagellin were recognized more frequently in patients with IBS. Furthermore, these antibodies were found more frequently in postinfectious compared with unspecific IBS. In patients with Crohn's disease, antiflagellin antibodies were detected with an increased frequency and at higher concentrations than in patients with IBS. All together, these results indicated the presence of a systemic immune activation in IBS patients, characterized by specific antibodies directed against luminal bacterial antigens. Furthermore, these results support the hypothesis that a subset of IBS presents an immune activation with pathogenic features common with IBD.