The effects of and interactions between fermentable dietary fiber and lipid in germfree and conventional mice

Dietary fiber can stimulate intestinal epithelial cell proliferation. The aim of this study was to resolve the different roles of fermentation and intraluminal viscosity on this trophic action and to investigate reported interactions between fiber and dietary fat. Conventional and germfree mice were fed guar gum in combination with low- or high-lipid diets for 2 weeks, and crypt cell production rates were determined. Guar gum significantly stimulated proliferation in the small intestine, especially when combined with fat. Lipid itself also stimulated proliferation in the small intestine and had a direct trophic effect in the cecum and colon of the germfree mice. Fiber markedly stimulated proliferation in the cecum and colon but only in the conventional group. Interactions between lipid and bacteria and between guar gum and bacteria were also observed in the small intestine. Guar gum has a trophic effect in the small bowel, probably related to viscosity, in addition to its fermentation-related actions in the colon. Positive interaction with lipid may be associated with delayed absorption. Lipid also has its own direct actions on small bowel mucosal proliferation, which are attenuated by the presence of bacteria.     

Concurrent small bowel adenocarcinoma and carcinoid tumor in Crohn's disease — Case report and literature review

Adenocarcinomas of the large and small bowel, as well as intestinal carcinoid tumors have been reported at increased rates in Crohn's disease. We herein report a rare case of concurrent adenocarcinoma and carcinoid tumor of the small bowel presenting as intestinal obstruction and found incidentally at laparotomy in a 55 year old male with longstanding ileal Crohn's disease. We performed a Medline Pubmed search for cases of synchronous or composite adenocarcinoma and carcinoid tumor in the setting of Crohn's disease and identified four similar cases. Concurrent adenocarcinoma and carcinoid tumor occurred both in newly diagnosed and longstanding Crohn's disease, most commonly involved the terminal ileum and presented with symptoms mimicking Crohn's disease. Diagnosis was made incidentally at laparotomy in all cases. Lymph node involvement was variable. Clinicians should be aware of this rare entity for expeditious surgical intervention.     

Atrioventricular node fetal dispersion and His bundle fragmentation of the cardiac conduction system in sudden cardiac death

Objectives. This study sought to examine the frequency of persistent fetal dispersion of the atrioventricular (AV) node and fragmentation of the atrioventricular bundle (His) bundle in the cardiac conduction system of sudden cardiac death cases and control subjects to establish their importance as the cause of death.

Background. These are two of the most frequent lesions reported in published reports in the cardiac conduction system in unexplained sudden deaths.

Methods. We have studied the conduction system of 347 hearts: 249 hearts from sudden cardiac death cases and 98 control hearts. The sudden cardiac death cases were divided, according to the pathology found, in three groups: group I: ischemic heart disease, 137 cases; group II: nonischemic heart disease, 48 cases, and group III: unexplained sudden cardiac deaths, 64 cases. The control group (group IV) consisted of patients with unnatural deaths and extracardiac natural deaths.

Results. Persistent fetal dispersion of the AV node was observed in 70 cases (20.17%) of all groups with a frequency (40.81%) statistically higher in the control group. Fragmentation of the His bundle was observed in 95 cases (31.77%), and the frequency was statistically higher in the control group, too (47.67%).

Conclusions. Persistent fetal dispersion of the AV node and fragmentation of the His bundle can be a normal variation present during many years in life and must not be considered the anatomic substrate for arrhythmias and sudden death without electrocardiographic abnormalities.