The pro-inflammatory cytokine interleukin (IL)-6 (refs. 1-5) can bind to cells lacking the IL-6 receptor (IL-6R) when it forms a complex with the soluble IL-6R (sIL-6R) (trans signaling). Here, we have assessed the contribution of this system to the increased resistance of mucosal T cells against apoptosis in Crohn disease (CD), a chronic inflammatory disease of the gastrointestinal tract. A neutralizing antibody against IL-6R suppressed established experimental colitis in various animal models of CD mediated by type 1 T-helper cells, by inducing apoptosis of lamina propria T cells. Similarly, specific neutralization of sIL-6R in vivo by a newly designed gp130-Fc fusion protein caused suppression of colitis activity and induction of apoptosis, indicating that sIL-6R prevents mucosal T-cell apoptosis. In patients with CD, mucosal T cells showed strong evidence for IL-6 trans signaling, with activation of signal transducer and activator of transcription 3, bcl-2 and bcl-xl. Blockade of IL-6 trans signaling caused T-cell apoptosis, indicating that the IL-6-sIL-6R system mediates the resistance of T cells to apoptosis in CD. These data indicate that a pathway of T-cell activation driven by IL-6-sIL-6R contributes to the perpetuation of chronic intestinal inflammation. Specific targeting of this pathway may be a promising new approach for the treatment of CD.

Gallbladder perforation and stone spillage might cause hazardous complications. In cases with loss of numerous or large pigment stones which cannot be retrieved by laparoscopy, intraoperative conversion to open surgery can be justified.

Nanofabricated pores in 20 nm-thick silicon nitride membranes were used to probe various protein analytes as well as to perform an antigen-antibody binding assay. A two-compartment electrochemical cell was separated by a single nanopore, 28 nm in diameter. Adding proteins to one compartment caused current perturbations in the ion current flowing through the pore. These perturbations correlated with both the charge and the size of the protein or of a protein-protein complex. The potential of this nanotechnology for studying protein-protein interactions is highlighted with the sensitive detection of -human chorionic gonadotropin, a hormone and clinical biomarker of pregnancy, by monitoring in real time and at a molecular level the formation of a complex between hormones and antibodies in solution. In this form, the assay compared advantageously to immunoassays, with the important difference that labels, immobilization, or amplification steps were no longer needed. In conclusion, we present proof-of-principle that properties of proteins and their interactions can be investigated in solution using synthetic nanopores and that these interactions can be exploited to measure protein concentrations accurately.The development of more sensitive assays for proteins is highly desirable as it will have a major impact in proteomics (i.e., for the understanding of the role of proteins in complex processes) and in clinical diagnostics (i.e., for alternative test formats). Classic immunoassays, which are routinely used for protein detection, have a sensitivity that is significantly lower than deoxyribonucleic acid (DNA) assays based on an amplification by means of polymerase chain reaction (PCR).1 An elegant way to boost the sensitivity of protein assays is, hence, to use DNA as a label and employ DNA amplification, for example in immuno-PCR 2 or biobarcode assays, 3 which allow a significant decrease in the detection limits to a few tens of proteins.In parallel to these developments, the detection of single biological molecules has become accessible using ultrasensitive fluorescence microscopy, 4-6 which, together with scanning probe microscopy (SPM), 7 is able to reveal inter-and intramolecular interactions and structural information. 8,9 However, the above methods for protein analysis have inherent limitations, such as a requirement for labels, immobilization, or complicated instrumentation that may be overcome with nanoporesensing.10,11 Some unique advantages of using nanopores are (i) no labeling or immobilization of the analyte is necessary; (ii) the instrumental setup is simple and does not require any moving parts, and (iii) it allows real-time detection of the analyte. Nanopores are therefore well suited for studying proteins and interactions between proteins under native conditions and at the single molecule level.Using the biological pore R-hemolysin, Meller et al. could distinguish DNA analytes which only differ in sequence. 11However, biological pores have practical limitations due to operating pH, temperature, a...

We report the detection of protein molecules with nanofabricated pores using the resistive pulse sensing method. A 20-nm-thick silicon nitride membrane with a nanofabricated pore measuring about 55nm in diameter separated an electrolyte cell into two compartments. Current spike trains were observed when bovine serum albumin (BSA) was added to the negatively biased compartment. The magnitude of the spikes corresponded to particles 7–9nm in diameter (the size of a BSA molecule) passing through the pore. This suggests that the current spikes were current blockages caused by single BSA molecules. The presented nano-Coulter counting method could be applied to detect single protein molecules in free solution, and to study the translocation of proteins through a pore.

Six hundred fifty-eight intestinal anastomoses in 429 operations for Crohn's disease were studied prospectively during an 8-year period to detect variables connected with perioperative morbidity. Postoperative complications occurred in 9.7% of the patients, 4% had to be reoperated on, and the overall mortality rate was 0.5%. In multivariate analysis by stepwise logistic regression, the only variable significantly (p = 0.03) associated with overall rate of complications was long-term corticosteroid therapy. Serious complications were more common in cases of intra-abdominal abscesses (p = 0.01) and preoperative steroid medication (p = 0.03). The combination of both of these risk factors increased the rate of reoperations from 0.6% (no steroids, no abscess) to 16% (steroids and abscess). No significant association with postoperative complications could be found for age, sex, duration of disease, previous operations, nutritional status, emergency surgery, extent of disease, type, number, and localization of anastomoses, presence of proximal ileo-/colostomy, or histologically inflamed margins of resection.