Part-Whole Relations in Object-Centered Systems: An Overview

Knowledge bases, data bases and object-oriented systems (referred to in the paper as Object-Centered systems) all rely on attributes as the main construct used to associate properties to objects; among these, a fundamental role is played by the so-called part-whole relation. The representation of such a structural information usually requires a particular semantics together with specialized inference and update mechanisms, but rarely do current modeling formalisms and methodologies give it a specific "first-class" dignity. The main thesis of this paper is that the part-whole relation cannot simply be considered as an ordinary attribute, its specific ontological nature requires to be understood and integrated within data modeling formalisms and methodologies. On the basis of such an ontological perspective, we survey the conceptual modeling issues involving part-whole relations, and the various modeling frameworks provided by knowledge representation and object-oriented formalisms

Campylobacter pylori and gastric mucosa. What method to use in the diagnosis?

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Natural history of gallstone disease: Expectant management or active treatment? Results from a population-based cohort study

Background and Aims: The knowledge of natural history is essential for disease management. We evaluated the natural history (e.g. frequency and characteristics of symptoms and clinical outcome) of gallstones (GS) in a population-based cohort study. Methods: A total of 11 229 subjects (6610 men, 4619 women, age-range: 29-69 years, mean age: 48 years) were studied. At ultrasonography, GS were present in 856 subjects (338 men, 455 women) (7.1%). GS were followed by means of a questionnaire inquiring about the characteristics of specific biliary symptoms. Results: At enrolment, 580 (73.1%) patients were asymptomatic, 94 (11.8%) had mild symptoms and 119 (15.1%) had severe symptoms. GS patients were followed up for a mean period of 8.7 years; 63 subjects (7.3%) were lost to follow up. At the end of the follow up, of the asymptomatic subjects, 453 (78.1%) remained asymptomatic; 61 (10.5%) developed mild symptoms and 66 (11.4%) developed severe symptoms. In subjects with mild symptoms, the symptoms disappeared in 55 (58.5%), became severe in 23 (24.5%), remained stable in 16 (17%); in subjects with severe symptoms, the symptoms disappeared in 62 (52.1%), became mild in 20 (16.8%) and remained stable in 37 (31.1%). A total of 189 cholecystectomies were performed: 41.3% on asymptomatic patients, 17.4% on patients with mild symptoms and 41.3% on patients with severe symptoms. Conclusions: This study indicates that: (i) asymptomatic and symptomatic GS patients have a benign natural history; (ii) the majority of GS patients with severe or mild symptoms will no longer experience biliary pain; and (iii) a significant proportion of cholecystectomies are performed in asymptomatic patients. Expectant management still represents a valid therapeutic approach in the majority of patients

Incidence of gallstone disease in Italy: Results from a multicenter, population-based Italian study (the MICOL project)

AIM: To evaluate gallstone incidence and risk factors in a large population-based study

Confirmatory factor analysis of the Patient Assessment of Constipation-Symptoms (PAC-SYM) among patients with chronic constipation

Background and aim: PAC-SYM is widely adopted to asses constipation severity. However, it has been validated in a small sample, few items have been included based on expert opinion and not on empirical grounds, and its factor structure has never been replicated. We aimed at evaluating the psychometric properties of PAC-SYM in patients with chronic constipation. Methods: We enrolled 2,203 outpatients with chronic constipation in two waves. We used wave I sample to test the psychometric properties of the PAC-SYM and wave II sample to cross-validate its factor structure, to assess criterion validity, responsiveness to clinical change, and its minimal clinically important difference. Results: Only a minority of patients reported any rectal tearing (38 %). Deletion of such item leads to a 11-item version (M:PAC-SYM). The remaining items in the rectal domain were moderately correlated with the stool domain. Exploratory factor analysis and confirmatory factor analysis revealed a bifactor structure with two subscales (stool and abdominal symptoms) and a general severity factor. The M:PAC-SYM demonstrated excellent reliability, moderate correlation with SF-12 and treatment satisfaction (r = 0.28-0.45), discrimination across Rome III criteria for functional constipation and abdominal pain, and responsiveness to clinical change (β = -0.49; ω2 = 0.25). M:PAC-SYM minimal clinically important difference was 0.24. Conclusion: Our analysis shows that the rectal domain may not represent a relevant cluster of symptoms for patients with chronic constipation. We developed a modified version of the PAC-SYM which might better represent symptom severity of most patients seeking care in gastroenterology referral centers

Bloating is associated with worse quality of life, treatment satisfaction, and treatment responsiveness among patients with constipation-predominant irritable bowel syndrome and functional constipation

Background: The management of bloating is unclear and its relationship with patients' well-being and treatment satisfaction independent of other abdominal symptoms is uncharacterized. We evaluated the association of bloating with patient-reported outcomes. Methods: Thirty-nine centers for functional gastrointestinal disorders joined the laxative inadequate relief survey. We enrolled 2203 consecutive outpatients with functional constipation (FC) or constipation-predominant irritable bowel syndrome (IBS-C) in two cross-sectional waves. Both wave 1 and 2 included the SF-12, the patient assessment of constipation-symptoms (PAC-SYM), and the treatment satisfaction questionnaire for medication (TSQM-2). Wave 2 only included a global rating of change (GRC) scale to assess patients' assessment of efficacy concerning treatment switches occurred in the 3 months prior to the interview. Bloating in the abdomen was defined on the basis of PAC-SYM item 3. Key Results: The average age was 50.1 years (SD, 16.7) and 82.1% of patients were women. The prevalence of bloating was 91.6% (n = 1970). Bloating was associated with SF-12 Physical Composite Score (p < 0.01), SF-12 Mental Composite Score (p < 0.01), GRC (p < 0.01), Satisfaction with treatment effectiveness (p < 0.01), convenience of administration (p < 0.01), and side effects (p < 0.01) after adjustment for possible confounders. Conclusions & Inferences: Our data suggest that patients regard bloating as a key element in assessing clinical changes and treatments' efficacy as this symptom exerts a strong influence on patient-reported outcomes independent of possible confounders and other symptoms of constipation. Our data provide the rationale to investigate the efficacy and tolerability of new treatments specifically addressing this important, yet disregarded, patients' complain