A rare diagnosis of Langerhans cell histiocytosis made on thyroid histology with coexisting papillary thyroid cancer and AVP deficiency.

Summary: A 48-year-old Asian male, presented to the hospital for an elective total thyroidectomy in the context of 6.3 cm thyroid nodule. The fine needle aspiration cytology of the nodule confirmed papillary thyroid cancer (PTC) with some atypical histiocytes. He has a history of idiopathic arginine vasopressin deficiency (AVP-D) and has been taking oral DDAVP 100 µg daily, self-adjusting the dose based on thirst and polyuria. Additionally, he also has a history of recurrent spontaneous pneumothorax. His total thyroidectomy was aborted due to significant intraoperative bleeding, and his admission was further complicated by post-operative hyponatraemic seizure. Thyroid histology revealed the diagnosis of Langerhans cell histiocytosis (LCH), and further investigation with contrast CT demonstrated multi-organ involvement of the thyroid, lungs, and bones. Learning points: Langerhans cell histiocytosis (LCH) is a condition that can affect one or more organ systems, including the pituitary, where it can present as AVP deficiency. Strict monitoring of fluid balance, as well as serial monitoring of serum sodium, is essential in all patients with AVP-D in the perioperative setting. Iatrogenic hyponatraemic seizure is an uncommon but serious complication of DDAVP treatment in hospitalised patients with AVP-D. DDAVP dosing must be carefully monitored. LCH with multisystem involvement is an important mimic for metastatic conditions, and histological diagnosis is essential to guide treatment and prognosis. Although LCH without bone marrow involvement is unlikely to increase the risk of bleeding, its effect on tissue integrity may make surgery more challenging. BRAF-V600E mutation is an important driver mutation and a potential therapeutic target in the treatment of LCH.

Structural malleability of plasticins: preorganized conformations in solution and relevance for antimicrobial activity.

Plasticins (23 long-residue glycine-leucine-rich dermaseptin-related peptides produced by the skin of South American hylids) have very similar amino acid sequences, hydrophobicities, and amphipathicities, but differ in their membrane-damaging properties and structurations (i.e. destabilized helix states, beta-hairpin, beta-sheet, and disordered states) at anionic and zwitterionic membrane interfaces. Structural malleability of plasticins in aqueous solutions together with parameters that may govern their ability to fold within beta-hairpin like structures were analyzed through circular dichroism and FTIR spectroscopic studies completed by molecular dynamics simulations in polar mimetic media. The goal of this study was to probe to which extent pre-existent peptide conformations, i.e. intrinsic "conformational landscape", may be responsible for variability in bioactive conformation and antimicrobial/hemolytic mechanisms of action of these peptides in relation with their various membrane disturbing properties. All plasticins present a turn region that does not always result in folding into a beta-hairpin shaped conformation. Residue at position 8 plays a major role in initiating the folding, while position 12 is not critical. Conformational stability has no major impact on antimicrobial efficacy. However, preformed beta-hairpin in solution may act as a conformational lock that prevents switch to alpha-helical structure. This lock lowers the antimicrobial efficiency and explains subtle differences in potencies of the most active antimicrobial plasticins.

Level of chronic life stress predicts clinical outcome in irritable bowel syndrome.

BACKGROUND: Life stress contributes to symptom onset and exacerbation in the majority of patients with irritable bowel syndrome (IBS) and functional dyspepsia (FD); research evidence is conflicting, however, as to the strength of these effects. AIMS: To test prospectively the relation of chronic life stress threat to subsequent symptom intensity over time. PATIENTS: One hundred and seventeen consecutive outpatients satisfying the modified Rome criteria for IBS (66% with one or more concurrent FD syndromes) participated. METHODS: The life stress and symptom intensity measures were determined from interview data collected independently at entry, and at six and 16 months; these measures assessed the potency of chronic life stress threat during the prior six months or more, and the severity and frequency of IBS and FD symptoms during the following two weeks. RESULTS: Chronic life stress threat was a powerful predictor of subsequent symptom intensity, explaining 97% of the variance on this measure over 16 months. No patient exposed to even one chronic highly threatening stressor improved clinically (by 50%) over the 16 months; all patients who improved did so in the absence of such a stressor. CONCLUSION: The level of chronic life stress threat predicts the clinical outcome in most patients with IBS/FD.

Fructose-sorbitol malabsorption and symptom provocation in irritable bowel syndrome: relationship to enteric hypersensitivity and dysmotility.

BACKGROUND: Fructose-sorbitol (F-S) mixtures can provoke symptoms in irritable bowel syndrome (IBS) patients, and a proportion of IBS patients also have enteric hypersensitivity to distension. We hypothesized, therefore, that sugar malabsorption and fermentation to produce hydrogen gas may provoke symptoms to a greater extent in IBS patients hypersensitive to distension than in those patients without such hypersensitivity. Our aims were therefore to compare, in IBS patients, symptoms and breath hydrogen responses after F-S, on the basis of jejunal sensitivity and jejunal motor function. METHODS: Fifteen female IBS patients (44 +/- 15 years) underwent, on separate occasions, 3-h breath hydrogen analyses after ingesting 10 g lactulose and 25 g fructose with 5 g sorbitol. Jejunal sensitivity and motor function were determined by balloon distension and 24-h manometry studies, respectively. Cumulative symptom scores and breath hydrogen production were analysed on the basis of the presence or absence of jejunal hypersensitivity and dysmotility. RESULTS: Four and seven patients had jejunal hypersensitivity for initial perception and pain, respectively. Eleven, nine, and nine patients had jejunal dysmotility for fasting phase 3, phase 2, and fed motor activity, respectively. Of the patients with symptom provocation after F-S (n = 8 within 3 h, n = 12 within 12 h) or with F-S malabsorption (n = 10), the relative proportion did not differ on the basis of the presence or absence of jejunal hypersensitivity or of motor dysfunction. Symptom scores and hydrogen production also were not different in these subgroups. CONCLUSIONS: Although carbohydrate malabsorption can provoke symptoms in some IBS patients, there is no consistent association between such a phenomenon and the presence of either jejunal hypersensitivity or dysmotility.

Functional gastrointestinal disorders: psychological, social, and somatic features.

BACKGROUND: Psychological, social, and extraintestinal (somatic) disturbances are prominent features of functional gastrointestinal disorders (FGID); little attention, however, has been given to differences in the nature of these disturbances in the various FGID subgroups. AIMS: (1) To determine whether psychological, social, and extraintestinal factors are associated with specific FGID, and/or with the overall severity and extent of FGID disturbance (the number of coexistent FGID subgroups present in any individual); and (2) to determine whether chronic social stressors link gastrointestinal, extraintestinal, and emotional symptomatologies in FGID. PATIENTS: One hundred and eighty eight outpatients, fulfilling standard criteria for one or more functional gastroduodenal or functional bowel disorders. METHODS: Utilising detailed and objective interview and questionnaire methods, detailed gastrointestinal, extraintestinal, psychological, and social data were collected. RESULTS: Chronic stressors and extraintestinal and emotional symptomatologies were prominent features of functional dyspepsia (FD) and irritable bowel syndrome (IBS) alone. These particular features were, however, highly specific for particular FD and/or IBS subgroups. The chronic threat component of social stressors predicted the nature and extent of multisystem (gastrointestinal, extraintestinal, and emotional) symptomatology. CONCLUSIONS: Notable differences between the various FGID subgroups support the symptom based classification of FGID. Chronic stressor provoked psychological and extraintestinal disturbance is most specific for the FD-IBS group of syndromes.