mKikGR, a Monomeric Photoswitchable Fluorescent Protein

The recent demonstration and utilization of fluorescent proteins whose fluorescence can be switched on and off has greatly expanded the toolkit of molecular and cell biology. These photoswitchable proteins have facilitated the characterization of specifically tagged molecular species in the cell and have enabled fluorescence imaging of intracellular structures with a resolution far below the classical diffraction limit of light. Applications are limited, however, by the fast photobleaching, slow photoswitching, and oligomerization typical for photoswitchable proteins currently available. Here, we report the molecular cloning and spectroscopic characterization of mKikGR, a monomeric version of the previously reported KikGR that displays high photostability and switching rates. Furthermore, we present single-molecule imaging experiments that demonstrate that individual mKikGR proteins can be localized with a precision of better than 10 nanometers, suggesting their suitability for super-resolution imaging

Combinatorial Roles of Heparan Sulfate Proteoglycans and Heparan Sulfates in Caenorhabditis elegans Neural Development

Heparan sulfate proteoglycans (HSPGs) play critical roles in the development and adult physiology of all metazoan organisms. Most of the known molecular interactions of HSPGs are attributed to the structurally highly complex heparan sulfate (HS) glycans. However, whether a specific HSPG (such as syndecan) contains HS modifications that differ from another HSPG (such as glypican) has remained largely unresolved. Here, a neural model in C. elegans is used to demonstrate for the first time the relationship between specific HSPGs and HS modifications in a defined biological process in vivo. HSPGs are critical for the migration of hermaphrodite specific neurons (HSNs) as genetic elimination of multiple HSPGs leads to 80% defect of HSN migration. The effects of genetic elimination of HSPGs are additive, suggesting that multiple HSPGs, present in the migrating neuron and in the matrix, act in parallel to support neuron migration. Genetic analyses suggest that syndecan/sdn-1 and HS 6-O-sulfotransferase, hst-6, function in a linear signaling pathway and glypican/lon-2 and HS 2-O-sulfotransferase, hst-2, function together in a pathway that is parallel to sdn-1 and hst-6. These results suggest core protein specific HS modifications that are critical for HSN migration. In C. elegans, the core protein specificity of distinct HS modifications may be in part regulated at the level of tissue specific expression of genes encoding for HSPGs and HS modifying enzymes. Genetic analysis reveals that there is a delicate balance of HS modifications and eliminating one HS modifying enzyme in a compromised genetic background leads to significant changes in the overall phenotype. These findings are of importance with the view of HS as a critical regulator of cell signaling in normal development and disease

Concomitant Carcinoma in situ in Cystectomy Specimens Is Not Associated with Clinical Outcomes after Surgery

Objective: The aim of this study was to externally validate the prognostic value of concomitant urothelial carcinoma in situ (CIS) in radical cystectomy (RC) specimens using a large international cohort of bladder cancer patients. Methods: The records of 3,973 patients treated with RC and bilateral lymphadenectomy for urothelial carcinoma of the bladder (UCB) at nine centers worldwide were reviewed. Surgical specimens were evaluated by a genitourinary pathologist at each center. Uni- and multivariable Cox regression models addressed time to recurrence and cancer-specific mortality after RC. Results: 1,741 (43.8%) patients had concomitant CIS in their RC specimens. Concomitant CIS was more common in organ-confined UCB and was associated with lymphovascular invasion (p < 0.001). Concomitant CIS was not associated with either disease recurrence or cancer-specific death regardless of pathologic stage. The presence of concomitant CIS did not improve the predictive accuracy of standard predictors for either disease recurrence or cancer-specific death in any of the subgroups. Conclusions: We could not confirm the prognostic value of concomitant CIS in RC specimens. This, together with the discrepancy between pathologists in determining the presence of concomitant CIS at the morphologic level, limits the clinical utility of concomitant CIS in RC specimens for clinical decision-making. Copyright (C) 2011 S. Karger AG, Base

Post-transplant lymphoproliferative disorder involving the ovary as an initial manifestation: a case report

<p>Abstract</p> <p>Introduction</p> <p>Because the normal ovary is assumed to be devoid of lymphoid tissue, it is unusual for it to be an initial manifestation of malignant lymphoma. This case is the first report, to our knowledge, of post-transplant lymphoproliferative disorder involving the ovary as an initial manifestation.</p> <p>Case presentation</p> <p>Twenty-nine weeks after a living renal transplantation, a 38-year-old Japanese female, whose ethnic origin was Asian, presented with abdominal pain and a chronic high fever. Computed tomography revealed a right ovarian tumor and liver metastases. The patient underwent oophrectomy based on the clinical diagnosis of liver metastasis from the primary ovarian tumor. The pathological diagnosis was Epstein-Barr Virus-associated post-transplant lymphoproliferative disorder. While ovarian malignant lymphoma has a poor prognosis, complete remission of liver involvement in this case was achieved only with a reduction of immunosuppressants.</p> <p>Conclusion</p> <p>Clinicians should remember that malignant lymphoma could initially involve the ovary, especially if the patient is immunosuppressed after transplantation therapy.</p

Character of valence-band states in the Kondo surface alloys CeAgx/Ag(111) and CePt5/Pt(111)

The crystal and electronic structures of the CePt5 and CeAgx surface alloys have been investigated by means of low-energy electron diffraction and angle-resolved photoelectron spectroscopy. From measurements performed near the 4d-4f absorption edge we were able to infer the weight of the 4f-electron spectral function with respect to the single-particle density of states. While the typical Kondo features at the Fermi energy (Kondo resonance and spin-orbit partner) in the CePt5 surface alloy were observed, only the f0 ionization structure and the spin-orbit partner were present in the CeAgx case. From our experiments, and by comparison to model calculations, we were able to estimate the Kondo temperature in the two systems and investigate parameters contributing to the hybridization strength