Solid bifocal pseudopapillary neoplasm of the pancreas: A case report.

Introduction: This neoplasm of the pancreas is an uncommon entity, with a frequency of 0.3-2.7% of all pancreatic tumors and even more so the finding of a synchronous lesion of the same histological lineage.

Multiple synchronous adenocarcinomas of the small bowel in a young patient: A case report.

Introduction: Adenocarcinoma of the small bowel is a rare neoplasm presented usually in elder patients as a single tumor. Its presentation as multiple tumors and in young patients is exceptional and there aren't any guidelines to orient its therapy.

Presentation Of Case: We present the rare case of a sixteen-year-old woman that presents to the emergency department with an intussusception due to a small bowel tumor.

PEGylation of protein-based MRI contrast agents improves relaxivities and biocompatibilities.

Magnetic resonance imaging (MRI) has emerged as a leading diagnostic technique in clinical and preclinical settings. However, the application of MRI to assess specific disease markers for diagnosis and monitoring drug effect has been severely hampered by the lack of desired contrast agents with high relaxivities, and optimized in vivo retention time. We have reported the development of protein-based MRI contrast agents (ProCA1) by rational design of Gd(3+) binding sites into a stable protein resulting in significantly increased longitudinal (r(1)) and transverse (r(2)) relaxivities compared to Gd-DTPA.

Calmodulin regulates Ca2+-sensing receptor-mediated Ca2+ signaling and its cell surface expression.

The Ca(2+)-sensing receptor (CaSR) is a member of family C of the GPCRs responsible for sensing extracellular Ca(2+) ([Ca(2+)](o)) levels, maintaining extracellular Ca(2+) homeostasis, and transducing Ca(2+) signaling from the extracellular milieu to the intracellular environment. In the present study, we have demonstrated a Ca(2+)-dependent, stoichiometric interaction between CaM and a CaM-binding domain (CaMBD) located within the C terminus of CaSR (residues 871-898). Our studies suggest a wrapping around 1-14-like mode of interaction that involves global conformational changes in both lobes of CaM with concomitant formation of a helical structure in the CaMBD.

Protein-based MRI contrast agents for molecular imaging of prostate cancer.

Purpose: The purpose of this study was to demonstrate a novel protein-based magnetic resonance imaging (MRI) contrast agent that has the capability of targeting prostate cancer and which provides high-sensitivity MR imaging in tumor cells and mouse models.

Procedure: A fragment of gastrin-releasing peptide (GRP) was fused into a protein-based MRI contrast agent (ProCA1) at different regions. MR imaging was obtained in both tumor cells (PC3 and H441) and a tumor mouse model administrated with ProCA1.

A single EF-hand isolated from STIM1 forms dimer in the absence and presence of Ca2+.

Stromal interaction molecule 1 (STIM1) is responsible for activating the Ca(2+) release-activated Ca(2+) (CRAC) channel by first sensing the changes in Ca(2+) concentration in the endoplasmic reticulum ([Ca(2+)](ER)) via its luminal canonical EF-hand motif and subsequently oligomerizing to interact with the CRAC channel pore-forming subunit Orai1. In this work, we applied a grafting approach to obtain the intrinsic metal-binding affinity of the isolated EF-hand of STIM1, and further investigated its oligomeric state using pulsed-field gradient NMR and size-exclusion chromatography. The canonical EF-hand bound Ca(2+) with a dissociation constant at a level comparable with [Ca(2+)](ER) (512 +/- 15 microm).

Multiple Ca(2+)-binding sites in the extracellular domain of the Ca(2+)-sensing receptor corresponding to cooperative Ca(2+) response.

A small change in the extracellular Ca(2+) concentration ([Ca(2+)](o)) integrates cell signaling responses in multiple cellular and tissue networks and functions via activation of Ca(2+)-sensing receptors (CaSR). Mainly through binding of Ca(2+) to the large extracellular domain (ECD) of the dimeric CaSR, intracellular Ca(2+) responses are highly cooperative with an apparent Hill coefficient ranging from 2 to 4. We have previously reported the identification of two continuous putative Ca(2+)-binding sites by grafting CaSR-derived, Ca(2+)-binding peptides to a scaffold protein, CD2, that does not bind Ca(2+).

Identification and dissection of Ca(2+)-binding sites in the extracellular domain of Ca(2+)-sensing receptor.

Ca(2+)-sensing receptors (CaSRs) represent a class of receptors that respond to changes in the extracellular Ca(2+) concentration ([Ca(2+)](o)) and activate multiple signaling pathways. A major barrier to advancing our understanding of the role of Ca(2+) in regulating CaSRs is the lack of adequate information about their Ca(2+)-binding locations, which is largely hindered by the lack of a solved three-dimensional structure and rapid off rates due to low Ca(2+)-binding affinities. In this paper, we have reported the identification of three potential Ca(2+)-binding sites in a modeled CaSR structure using computational algorithms based on the geometric description and surface electrostatic potentials.