Intermittent Stem Cell Cycling Balances Self-Renewal and Senescence of the C. elegans Germ Line.

Self-renewing organs often experience a decline in function in the course of aging. It is unclear whether chronological age or external factors control this decline, or whether it is driven by stem cell self-renewal-for example, because cycling cells exhaust their replicative capacity and become senescent. Here we assay the relationship between stem cell cycling and senescence in the Caenorhabditis elegans reproductive system, defining this senescence as the progressive decline in "reproductive capacity," i.e. in the number of progeny that can be produced until cessation of reproduction. We show that stem cell cycling diminishes remaining reproductive capacity, at least in part through the DNA damage response. Paradoxically, gonads kept under conditions that preclude reproduction keep cycling and producing cells that undergo apoptosis or are laid as unfertilized gametes, thus squandering reproductive capacity. We show that continued activity is in fact beneficial inasmuch as gonads that are active when reproduction is initiated have more sustained early progeny production. Intriguingly, continued cycling is intermittent-gonads switch between active and dormant states-and in all likelihood stochastic. Other organs face tradeoffs whereby stem cell cycling has the beneficial effect of providing freshly-differentiated cells and the detrimental effect of increasing the likelihood of cancer or senescence; stochastic stem cell cycling may allow for a subset of cells to preserve proliferative potential in old age, which may implement a strategy to deal with uncertainty as to the total amount of proliferation to be undergone over an organism's lifespan.

It is time for a better clip applier - 3 mm, percutaneous, non-crushing and locking.

INTRODUCTION: Since the advent of laparoscopy there have been attempts to minimize abdominal wall incisions. For this purpose smaller instruments have been produced. Our aim was to develop the first 3 mm percutaneous clip applier and to make it better than the standard clips of today. MATERIAL AND METHODS: The ClipTip clip is made of Nitinol and has a crocodile shaped jaws, which when apposed effectively seal vessels. The shaft operates as a retractable needle permitting percutaneous insertion. Closing, reopening and reclosing is possible. The physical properties of the device were compared to three commercially available clip appliers. Surgeries were performed on porcine animals by experienced surgeons. RESULTS: In comparison to available clips, the superiority of the ClipTip is a combination of wide effective length alongside the ability to withstand strong forces. In live animal studies the Cliptip was inserted into the peritoneal cavity without any injuries. Vessels were ligated successfully and no clip dislodgement or leakage occurred. CONCLUSIONS: We developed the next generation clip applier with better properties. Advantages include its length, the needleoscopic caliber, non-crushing effect, locking mechanism and wide aperture. The device has performed safely and effectively in pre-clinical tests. Further studies are planned in humans.

Control of Caenorhabditis elegans germ-line stem-cell cycling speed meets requirements of design to minimize mutation accumulation.

BACKGROUND: Stem cells are thought to play a critical role in minimizing the accumulation of mutations, but it is not clear which strategies they follow to fulfill that performance objective. Slow cycling of stem cells provides a simple strategy that can minimize cell pedigree depth and thereby minimize the accumulation of replication-dependent mutations. Although the power of this strategy was recognized early on, a quantitative assessment of whether and how it is employed by biological systems is missing. RESULTS: Here we address this problem using a simple self-renewing organ - the C. elegans gonad - whose overall organization is shared with many self-renewing organs. Computational simulations of mutation accumulation characterize a tradeoff between fast development and low mutation accumulation, and show that slow-cycling stem cells allow for an advantageous compromise to be reached. This compromise is such that worm germ-line stem cells should cycle more slowly than their differentiating counterparts, but only by a modest amount. Experimental measurements of cell cycle lengths derived using a new, quantitative technique are consistent with these predictions. CONCLUSIONS: Our findings shed light both on design principles that underlie the role of stem cells in delaying aging and on evolutionary forces that shape stem-cell gene regulatory networks.

Analysis of in vivo single cell behavior by high throughput, human-in-the-loop segmentation of three-dimensional images.

BACKGROUND: Analysis of single cells in their native environment is a powerful method to address key questions in developmental systems biology. Confocal microscopy imaging of intact tissues, followed by automatic image segmentation, provides a means to conduct cytometric studies while at the same time preserving crucial information about the spatial organization of the tissue and morphological features of the cells. This technique is rapidly evolving but is still not in widespread use among research groups that do not specialize in technique development, perhaps in part for lack of tools that automate repetitive tasks while allowing experts to make the best use of their time in injecting their domain-specific knowledge. RESULTS: Here we focus on a well-established stem cell model system, the C. elegans gonad, as well as on two other model systems widely used to study cell fate specification and morphogenesis: the pre-implantation mouse embryo and the developing mouse olfactory epithelium. We report a pipeline that integrates machine-learning-based cell detection, fast human-in-the-loop curation of these detections, and running of active contours seeded from detections to segment cells. The procedure can be bootstrapped by a small number of manual detections, and outperforms alternative pieces of software we benchmarked on C. elegans gonad datasets. Using cell segmentations to quantify fluorescence contents, we report previously-uncharacterized cell behaviors in the model systems we used. We further show how cell morphological features can be used to identify cell cycle phase; this provides a basis for future tools that will streamline cell cycle experiments by minimizing the need for exogenous cell cycle phase labels. CONCLUSIONS: High-throughput 3D segmentation makes it possible to extract rich information from images that are routinely acquired by biologists, and provides insights - in particular with respect to the cell cycle - that would be difficult to derive otherwise.

Radical cystectomy with W-shaped orthotopic ileal neobladder constructed with non-absorbable titanium staples-long term follow-up.

PURPOSES: We retrospectively assessed our experience with the W-shaped orthotopic ileal pouch, which was constructed with non-absorbable titanium staples. For these purpose, we discuss the results of bladder capacity, urinary continence and early and long-term postoperative complications. MATERIALS AND METHODS: We included in the study 17 patients who underwent radical cystoprostatectomy followed by construction of an orthotopic W-shaped ileal pouch between October 2000 and November 2009. A 65-70 cm segment of ileum was isolated and prearranged into a W-configuration, leaving two 10 cm intact segments on both sides of the ileal fragment. In our technique we entirely anatomized all adjacent limbs in order to create a sphere-shaped pouch. The ureters were directly anastomized to both intact segments of the ileal division. All our patients underwent pouchscopy 6 months after operation and annually. RESULTS: Mean operative time for neobladder reconstruction and ureteral anastomoses was 87 ± 7.67 minutes. In one patient a leak from the ileo-ileal anastomosis was confirmed on the 3rd day after operation. In 2 cases unilateral stricture of the ureteral-neobladder anastomosis was documented. Staple lines were mostly covered with ileal mucosa after 6 months. The mean functional bladder capacity was 340 ± 27.6 mL and 375 ± 43.4 mL at 6 and 12 months, respectively. First-year daytime and nighttime continence was good and acceptable in 90% and 78% of patients, while it increased to 95% during the 2nd year. CONCLUSIONS: The long term follow-up shows that non-absorbable titanium staples can be safely used for creation of an orthotopic ileal neobladder. However, these data should be further validated in a larger series of patients.

A novel device for protecting rectum during prostate cancer irradiation: in vivo data on a large mammal model.

PURPOSE: Hypofractionation schemes and associated higher rectal doses have evoked the need for improved protection of the rectum during prostate cancer irradiation. MATERIALS AND METHODS: An implantable, biodegradable, inflatable, preshaped triangular balloon of commercially used poly(L-lactide-co-epsilon-caprolactone) co-polymer material was developed to provide separation between prostate and rectum. Biocompatibility and degradability of the balloon implanted subcutaneously or perineally, and in the context of transperineal implantation and local irradiation were evaluated in several in vivo studies. RESULTS: The device was found to be biocompatible in subcutaneously implanted rabbits up to 42 days, in a transperineally implanted dog up to 12 months and in 8 transperineally implanted pigs up to 6 months. Upon inflation in situ the balloon separated the tissues, remained inflated for several months and subsequently biodegraded. No systemic or local toxicity was noted, as shown by histopathology. Device insertion into the perineal area using a dedicated introductory kit was convenient and feasible. Three-month followup in irradiated pigs that received 15 Gy in 3 fractions 1 week apart showed a stable balloon position with no local or systemic side effects. CONCLUSIONS: This novel device was safe and effective for its intended use of separating tissues for a desired duration. A clinical study will commence to evaluate the safety and efficacy of this device during irradiation in patients with prostate cancer.

Characterization of novel breast carcinoma-associated BA46-derived peptides in HLA-A2.1/D(b)-beta2m transgenic mice.

The human milk fat globule membrane protein BA46 (lactadherin) is highly overexpressed in human breast tumors, making it a potential target for tumor immunotherapy. We have identified BA46-derived peptides that contain the motif recognized by the MHC class I molecule HLA-A2.1 and that are processed and presented by human breast carcinoma cells. In mice lacking normal class I molecules but expressing an HLA-A2.1/D(b)-beta2 microglobulin single chain (HHD mice), three peptides elicited specific CTL activity. Two of these peptides also stimulated cytotoxic activity in peripheral blood lymphocytes from HLA-A2.1-positive breast carcinoma patients. Adoptive transfer of HHD-derived bulk CTLs to nude mice bearing human breast carcinoma transplants reduced tumor growth. These peptides therefore represent naturally processed BA46-derived CTL epitopes that can be used in peptide-based antitumor vaccines.

Human CTL epitopes prostatic acid phosphatase-3 and six-transmembrane epithelial antigen of prostate-3 as candidates for prostate cancer immunotherapy.

Specific immunotherapy of prostate cancer may be an alternative or be complementary to other approaches for treatment of recurrent or metastasized disease. This study aims at identifying and characterizing prostate cancer-associated peptides capable of eliciting specific CTL responses in vivo. Evaluation of peptide-induced CTL activity in vitro was done following immunization of HLA-A2 transgenic (HHD) mice. An in vivo tumor rejection was tested by adoptive transfer of HHD immune lymphocytes to nude mice bearing human tumors. To confirm the existence of peptide-specific CTL precursors in human, lymphocytes from healthy and prostate cancer individuals were stimulated in vitro in the presence of these peptides and CTL activities were assayed. Two novel immunogenic peptides derived from overexpressed prostate antigens, prostatic acid phosphatase (PAP) and six-transmembrane epithelial antigen of prostate (STEAP), were identified; these peptides were designated PAP-3 and STEAP-3. Peptide-specific CTLs lysed HLA-A2.1+ LNCaP cells and inhibited tumor growth on adoptive immunotherapy. Furthermore, peptide-primed human lymphocytes derived from healthy and prostate cancer individuals lysed peptide-pulsed T2 cells and HLA-A2.1+ LNCaP cells. Based on the results presented herein, PAP-3 and STEAP-3 are naturally processed CTL epitopes possessing anti-prostate cancer reactivity in vivo and therefore may constitute vaccine candidates to be investigated in clinical trials.

Combined dendritic cell cryotherapy of tumor induces systemic antimetastatic immunity.

PURPOSE: Cryotherapy of localized prostate, renal, and hepatic primary tumors and metastases is considered a minimally invasive treatment demonstrating a low complication rate in comparison with conventional surgery. The main drawback of cryotherapy is that it has no systemic effect on distant metastases. We investigated whether intratumoral injections of dendritic cells following cryotherapy of local tumors (cryoimmunotherapy) provides an improved approach to cancer treatment, combining local tumor destruction and systemic anticancer immunity. EXPERIMENTAL DESIGNS: The 3LL murine Lewis lung carcinoma clone D122 and the ovalbumin-transfected B16 melanoma clone MO5 served as models for spontaneous metastasis. The antimetastatic effect of cryoimmunotherapy was assessed in the lung carcinoma model by monitoring mouse survival, lung weight, and induction of tumor-specific CTLs. The mechanism of cryoimmunotherapy was elucidated in the melanoma model using adoptive transfer of T cell receptor transgenic OT-I CTLs into the tumor-bearing mice, and analysis of Th1/Th2 responses by intracellular cytokine staining in CD4 and CD8 cells. RESULTS: Cryoimmunotherapy caused robust and tumor-specific CTL responses, increased Th1 responses, significantly prolonged survival and dramatically reduced lung metastasis. Although intratumor administration of dendritic cells alone increased the proliferation rate of CD8 cells, only cryoimmunotherapy resulted in the generation of effector memory cells. Furthermore, cryoimmunotherapyprotected mice that had survived primary MO5 tumors from rechallenge with parental tumors. CONCLUSIONS: These results present cryoimmunotherapy as a novel approach for systemic treatment of cancer. We envisage that cryotherapy of tumors combined with subsequent in situ immunotherapy by autologous unmodified immature dendritic cells can be applied in practice.

Semi-permeable Diffusion Barriers Enhance Patterning Robustness in the C. elegans Germline.

Positional information derived from local morphogen concentration plays an important role in patterning. A key question is how morphogen diffusion and gene expression regulation shape positional information into an appropriate profile with suitably low noise. We address this question using a model system--the C. elegans germline--whose regulatory network has been well characterized genetically but whose spatiotemporal dynamics are poorly understood. We show that diffusion within the germline syncytium is a critical control of stem cell differentiation and that semi-permeable diffusion barriers present at key locations make it possible--in combination with a feedback loop in the germline regulatory network--for mitotic zone size to be robust against spatial noise in Notch signaling. Spatial averaging within compartments defined by diffusion barriers is an advantageous patterning strategy, which attenuates noise while still allowing for sharp transitions between compartments. This strategy could apply to other organs.

Live imaging reveals active infiltration of mitotic zone by its stem cell niche.

Stem cells niches are increasingly recognized as dynamic environments that play a key role in transducing signals that allow an organism to exert control on its stem cells. Live imaging of stem cell niches in their in vivo setting is thus of high interest to dissect stem cell controls. Here we report a new microfluidic design that is highly amenable to dissemination in biology laboratories that have no microfluidics expertise. This design has allowed us to perform the first time lapse imaging of the C. elegans germline stem cell niche. Our results show that this niche is strikingly dynamic, and that morphological changes that take place during development are the result of a highly active process. These results lay the foundation for future studies to dissect molecular mechanisms by which stem cell niche morphology is modulated, and by which niche morphology controls stem cell behavior.

Interstitial biodegradable balloon for reduced rectal dose during prostate radiotherapy: results of a virtual planning investigation based on the pre- and post-implant imaging data of an international multicenter study.

PURPOSE: To evaluate dose reduction caused by the implantation of an interstitial inflatable and biodegradable balloon device aiming to achieve lower rectal doses with virtual 3D conformal external beam radiation treatment. MATERIALS AND METHODS: An inflatable balloon device was placed, interstitially and under transrectal ultrasound guidance, into the rectal-prostate interspace prior treatment initiation of 26 patients with localized prostate cancer, who elected to be treated with radiotherapy (3D CRT or IMRT). The pre- and post-implant CT imaging data of twenty two patients were collected (44 images) for the purpose of the 3D conformal virtual planning presented herein. RESULTS: The dorsal prostate-ventral rectal wall separation resulted in an average reduction of the rectal V70% by 55.3% (± 16.8%), V80% by 64.0% (± 17.7%), V90% by 72.0% (± 17.1%), and V100% by 82.3% (± 24.1%). In parallel, rectal D2 ml and D0.1 ml were reduced by 15.8% (± 11.4%) and 3.9% (± 6.4%), respectively. CONCLUSIONS: Insertion of the biodegradable balloon into the prostate-rectum interspace is similar to other published invasive procedures. In this virtual dose distribution analysis, the balloon insertion resulted in a remarkable reduction of rectal volume exposed to high radiation doses. This effect has the potential to keep the rectal dose lower especially when higher than usual prostate dose escalation protocols or hypo-fractionated regimes are used. Further prospective clinical investigations on larger cohorts and more conformal radiation techniques will be necessary to define the clinical advantage of the biodegradable interstitial tissue separation device.

Safety and efficacy of a novel ureteral occlusion device.

OBJECTIVE: To evaluate the safety of a novel ureteral occlusion device and compare its performance with that of other devices and guidewires. METHODS: The XenX (Xenolith Medical) was tested in an ex vivo porcine model to determine the percentage of denuded urothelium because of manipulation within the ureter, the capacity to prevent stone migration during laser lithotripsy, stent compatibility, and the ability to be used for stent placement. Comparative evaluations of the insertion forces and maneuverability were conducted in an in vitro ureter model with the XenX, Stone Cone (Boston Scientific), NTrap (Cook Urological), HiWire (Cook Urological), Roadrunner (Cook Urological), and Sensor (Boston Scientific). Stone migration efficacy was measured using a controlled distribution of stones in 4- and 10-mm silicone tubing with the XenX, NTrap, and Stone Cone. RESULTS: The XenX was safely manipulated within the ureter, prevented significant particle migration during laser lithotripsy, and effectively placed stents. The NTrap required the greatest force when attempting to navigate past a stone (P = .0003), followed by the Stone Cone (P = .009), with little difference among the other devices (P > .72). No differences were found for the passing forces (P = .061), interval to pass (P = .30), or number of attempts to pass the stone (P = .68). The XenX prevented stone migration the most, with more notable differences in the 10- than in the 4-mm tubing. CONCLUSION: Ex vivo evaluations hold promise for the XenX to be safely and effectively used during ureteroscopic procedures. Clinical evaluations are warranted to confirm the safety and performance of the XenX relative to the other ureteral occlusion devices.

Biodegradable inflatable balloon for reducing radiation adverse effects in prostate cancer.

Carcinoma of the prostate is one of the most abundant killers for men in the western world, and it is frequently treated via Radiation therapy. Unfortunately, radiotherapy side effects include rectal irritation and bleeding, erectile dysfunction and urinary frequency. Because radiation intensity decays rapidly as a function of distance, displacing irradiated prostate away from normal tissues would reduce damage and therefore side effects. The objective of this study is to develop an inflatable balloon that is implanted via a minimal invasive procedure. The balloon is made of a biodegradable polymer called poly(lactide-co-epsilon-caprolactone). The implant is inserted rolled throughout the perineum; inflated in situ with a physiological saline; sealed and placed between the rectum wall, and the prostate gland. Balloon's mechanical and chemical properties were extensively characterized both in vitro and in vivo. The balloon's preparation ensures no bonding across surfaces as these may endanger the implant mechanical stability. Moreover, the coating method does not alter the polymer's molecular weight and therefore preserve its mechanical properties. Balloon's sterilization was carried out using ethylene oxide which, as our results show and in comparison with gamma-irradiation, doesn't damage the mechanical stability of the implant. The proper functionality of the insertion-mounting device as well as the balloon capability to retain its inflated form during patients' radiation session was demonstrated both in vitro and in vivo.

Radical cystectomy with W-shaped orthotopic ileal neobladder constructed with non-absorbable titanium staples-long term follow-up

Purposes We retrospectively assessed our experience with the W-shaped orthotopic ileal pouch, which was constructed with non –absorbable titanium staples. For these purpose, we discuss the results of bladder capacity, urinary continence and early and long-term postoperative complications. Materials and Methods We included in the study 17 patients who underwent radical cystoprostatectomy followed by construction of an orthotopic W-shaped ileal pouch between October 2000 and November 2009. A 65-70 cm segment of ileum was isolated and prearranged into a W- configuration, leaving two 10 cm intact segments on both sides of the ileal fragment. In our technique we entirely anatomized all adjacent limbs in order to create a sphere-shaped pouch. The ureters were directly anastomized to both intact segments of the ileal division. All our patients underwent pouchscopy 6 months after operation and annually. Results Mean operative time for neobladder reconstruction and ureteral anastomoses was 87 ± 7.67 minutes. In one patient a leak from the ileo-ileal anastomosis was confirmed on the 3rd day after operation. In 2 cases unilateral stricture of the ureteral-neobladder anastomosis was documented. Staple lines were mostly covered with ileal mucosa after 6 months. The mean functional bladder capacity was 340 ± 27.6 mL and 375 ± 43.4 mL at 6 and 12 months, respectively. First-year daytime and nighttime continence was good and acceptable in 90% and 78% of patients, while it increased to 95% during the 2nd year. Conclusions The long term follow-up shows that non-absorbable titanium staples can be safely used for creation of an orthotopic ileal neobladder. However, these data should be further validated in a larger series of patients. .

Preventive and therapeutic vaccination with PAP-3, a novel human prostate cancer peptide, inhibits carcinoma development in HLA transgenic mice.

Conventional treatment of recurrent and metastasized prostate cancer (CaP) remains inadequate; this fact mandates development of alternative therapeutic modalities, such as specific active or passive immunotherapy. Previously, we reported the identification of a novel highly immunogenic HLA-A*0201-restricted Prostatic Acid Phosphatase-derived peptide (PAP-3) by a two-step in vivo screening in an HLA-transgenic (HHD) mouse system. In the present study we aimed at elucidating the efficiency of PAP-3-based vaccine upon active antitumor immunization. To this end we established preventive and therapeutic carcinoma models in HHD mice. The 3LL murine Lewis lung carcinoma clone D122 transduced to express HLA-A*0201 and PAP served as a platform for these models. The HLA-A*0201-PAP-3 complex specific recombinant single chain scFV-PAP-3 antibodies were generated and used to confirm an endogenous PAP processing resulting in PAP-3 presentation by HLA-A*0201. PAP-3 based vaccines significantly decreased tumor incidence in a preventive immunization setting. Therapeutic vaccination of HHD mice with PAP-3 led to rejection of early established tumors and to increase of mouse survival. These results strongly support a therapeutic relevance of the identified CTL epitope upon active antitumor immunization. The newly established carcinoma model presented herein might be a useful tool for cancer vaccine design and optimization.

Active rectal wall protection using direct transperineal cryo-needles for histologically proven prostate adenocarcinomas.

INTRODUCTION AND OBJECTIVES: Cryosurgical ablation of the prostate is a promising new modality for the treatment localized prostate cancer. However, better protection of the rectal wall during cryoablation of the peripheral zone of the prostate (PZP) may permit deeper freezing of the PZP and for longer time, rendering the procedure safer and more effective. We present a modified cryoablation technique of the prostate using the SeedNet system (Galil Medical, Uniondale, NY, USA), in which the rectum is actively protected during cryoablation. PATIENTS AND METHODS: During a 12-month period, 31 patients (32 procedures) with localized and histologically proven prostate adenocarcinoma of various stages and grades were treated in this fashion. We evaluated the feasibility of a new method of active rectal wall protection during cryoablation of the prostate. Fourteen ultrathin, 17-gauge, probes, cryo-needles were percutaneously introduced under transrectal ultrasound (TRUS) guidance into the prostate. Peripheral region of the prostate and the area between the prostate and rectal wall were real time monitored for temperature changes. Two cryo-needles placed between the prostate and rectal wall served for active warming using the thawing mode when the temperatures dropped to approximately 0 degrees C, and rectal lumen washing with hot water (+40 degrees C) when the temperature reading dropped further to -8 degrees C or -10 degrees C. RESULTS: Active protection of the rectal wall using the cryosurgical modification of active thawing by the two additional cryo-needles placed in the space between the prostate and rectum, while freezing the prostate was performed in every patient, thus enabling us a safe generation of an iceball at the peripheral zone of the prostate with an average temperature ranging from -35 degrees C to -60 degrees C, for 10 min per cycle. During a follow-up of up to 18 months (mean 13.2 months) there was a PSA decrease to values equal or less than 0.5ng/ml in 25 patients (80.6%) and to values equal or less than 1 ng/ml in 21 patients (67.7%). There were no cases of rectal injury or postoperative rectal pain in any of these patients. CONCLUSIONS: This new cryotechnique of active rectal wall protection during cryotherapy of the prostate was safe and simple to perform, resulting in no rectal injuries. It was also very effective in ablating the prostate gland, as expressed by the low follow up PSA values.