Duodenal Ulcer with Massive Gastrointestinal Hemorrhage as an Initial Manifestation in Multiple Myeloma with Extramedullary Disease: A Case Report.

Plasma cell neoplasms are characterized by dysregulated proliferation of mature B cells, which can present with either single (solitary plasmacytoma) or systemic (multiple myeloma (MM)) involvement. MM with extramedullary plasmacytoma (EMP) is a rare disease that accounts for approximately 3-5% of all plasmacytomas. EMP with gastrointestinal (GI) system involvement is an even rarer entity, accounting for <1% of MM cases. We present a case of aggressive MM with EMP invading the duodenum, initially presented with massive upper GI hemorrhage and small bowel obstruction. A 67-year-old woman was admitted to our hospital owing to a lack of either gas or feces passage for 3 days. Abdominal distention and vomit with a high coffee ground content were observed for 24 h. The patient's condition was initially diagnosed as small bowel obstruction, upper gastrointestinal bleeding, severe anemia, acute renal failure, and hypercalcemia. Furthermore, an analysis of immunoelectrophoresis in the blood, bone marrow aspiration, and tissue biopsy supported the diagnosis of MM and EMP invading the duodenum, upper GI hemorrhage, and small bowel obstruction. Our study provided the possible involvement of MM and EMP in the differential diagnosis of patients with unexplained GI hemorrhage and small bowel obstruction. A thorough review of the literature regarding the association between MM, GI hemorrhage, and small bowel obstruction is presented in this study.

Structural aggregates of rod-coil copolymer solutions.

The optoelectronic properties of rod-coil diblock copolymers with π-conjugation are greatly affected by molecular packing, which is closely related to their micellar morphology. Self-assembly of rod-coil block copolymer B(y)A(x) in a selective solvent for its coil block is studied by using dissipative particle dynamics, where B(y)A(x) denotes the polymer comprising of y rodlike B beads and x coil-like A beads. The influences of polymer concentration, component compatibility, solvent quality for coil block, rod-block length, and π-π interaction on the resulting aggregate conformations are examined. It was found that distinctly different from coil-coil copolymers, the aggregates of rod-coil copolymers exhibit morphological and structural diversity induced by the intrinsically rigid nature of the rod blocks. In general, the aggregate adopts the overall shape of sphere, cylinder, perforated sheet, or network. The morphology of the rod-block domain within aggregate is even richer and the interesting structures such as porous sphere, spherical spiral, helical bundles, discrete chunks, and nematic cylinder are observed. The short-range order parameter indicates that as rod length is long enough, neighboring rods begin to orient parallel to one another and nematic domains appear. Moreover, in the presence of π-π interactions, the neighboring rods within the B domains become more coherently oriented and smectic domains can thus be formed.

Thin film morphologies of pi-conjugated rod-coil block copolymers with thermoresponsive property: a combined experimental and molecular simulation study.

A combined experimental and simulational investigation is performed to study the surface morphologies of polymer films formed by poly[2,7-(9,9-dihexylfluorene)]-b-poly[N-isopropylacrylamide] (PF-b-PNIPAAm) rod-coil block copolymers, where PF possesses pi-pi interactions and PNIPAAm is known to exhibit a coil-to-globule phase transition at T=32 degrees C. Two (PF-b-PNIPAAm) rod-coil block copolymers with different block ratios are synthesized and used to prepare thin films on the quartz glass by physisorption. The surface structures of the thermoresponsive polymer films are found to alter significantly in response to thermostimuli. Small, hemispherical domains of the aggregations of rod-blocks are formed at low temperatures. As the temperature increases, the conformations transform to isolated islands, wormlike structures, or even networklike morphologies depending on the grafting density. These morphological transformations due to temperature variation are consistent with simulation findings. The photophysical properties of PF-b-PNIPAAm films are also found to vary with thermostimuli. The PL spectra reveals that the emission originates from the aggregation of PF blocks and the intensity changes as temperature varies. Our study demonstrates that the surface morphologies and the corresponding photophysical properties of the PF-b-PNIPAAm polymer films can be tuned by thermostimuli.

Atypical micellization of star-block copolymer solutions.

The self-assembly of star-block copolymer (B(y)A(x))(n) in a selective solvent for its outer block is studied by using dissipative particle dynamics, where (B(y)A(x))(n) denotes a n-armed star with each arm comprising of y solvophobic B-segments and x solvophilic A-segments. The effects of arm number, arm length, block length ratio y/x, solvent quality, and component compatibility on mean aggregation number (p) are examined. Unusual micellization behaviors are observed. The total number of arms in a multimolecular micelle n(*) is invariant with the arm number but grows with the segment concentration phi, which is different from typical micellization of short-chain surfactants. For a given phi, multimolecular micelles are formed for stars with n < n(*)(phi) and the mean aggregation number follows (p) = n(*)n. As n > or = n(*), only unimolecular micelles exist in the solution. According to the n(*)-phi relation, the critical multimolecular micelle concentration is found to grow linearly with arm number. As solvent quality deteriorates or component compatibility increases, the total arm number within a micelle rises.

Morphologies of multicompartment micelles formed by triblock copolymers.

Multicompartment micelles are desirable for advanced applications such as drug delivery. Recently, core-shell-corona (CSC) and segmented-worm (SW) micelles formed by ABC triblock terpolymers with three mutually immiscible blocks are observed in experiments. We have performed dissipative particle dynamics simulations to study the effects of molecular architecture, block length, and solution concentration on the morphologies of ABC triblock terpolymers. The formation of CSC and SW micelles for linear and miktoarm star ABC terpolymers is confirmed in this work. In addition, we predict that different multicompartment micellar morphologies (e.g., incomplete skin-layered micelles and segmented worms) can be formed by linear copolymer with different arrangements of the three blocks.