Selective vascular coagulation of rabbit colon using a flashlamp-excited dye laser operating at 577 nanometers

Exploiting RIG-I-like receptor pathway for cancer immunotherapy

RIG-I-like receptors (RLRs) are intracellular pattern recognition receptors that detect viral or bacterial infection and induce host innate immune responses. The RLRs family comprises retinoic acid-inducible gene 1 (RIG-I), melanoma differentiation-associated gene 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2) that have distinctive features. These receptors not only recognize RNA intermediates from viruses and bacteria, but also interact with endogenous RNA such as the mislocalized mitochondrial RNA, the aberrantly reactivated repetitive or transposable elements in the human genome. Evasion of RLRs-mediated immune response may lead to sustained infection, defective host immunity and carcinogenesis. Therapeutic targeting RLRs may not only provoke anti-infection effects, but also induce anticancer immunity or sensitize "immune-cold" tumors to immune checkpoint blockade. In this review, we summarize the current knowledge of RLRs signaling and discuss the rationale for therapeutic targeting RLRs in cancer. We describe how RLRs can be activated by synthetic RNA, oncolytic viruses, viral mimicry and radio-chemotherapy, and how the RNA agonists of RLRs can be systemically delivered in vivo. The integration of RLRs agonism with RNA interference or CAR-T cells provides new dimensions that complement cancer immunotherapy. Moreover, we update the progress of recent clinical trials for cancer therapy involving RLRs activation and immune modulation. Further studies of the mechanisms underlying RLRs signaling will shed new light on the development of cancer therapeutics. Manipulation of RLRs signaling represents an opportunity for clinically relevant cancer therapy. Addressing the challenges in this field will help develop future generations of cancer immunotherapy.

Pulsed laser-induced thermal damage in whole blood

An investigation of the effects of laser irradiation with a wavelength of 532 nm and pulse duration of 10 ms on whole blood was performed in vitro. Threshold radiant exposures for coagulation were quantified and transient radiometric temperatures were measured. The progression of effects with increasing radiant exposure--from evaporation to coagulation-induced light scattering to aggregated coagulum formation to ablation--is described. Results indicate that coagulation and ablation occur at temperatures significantly in excess of those assumed in previous theoretical studies. An Arrhenius rate process analysis based on hemoglobin data indicates good agreement with experimental results.

Applications of lasers in gastroenterology

In this article the clinical uses of lasers in gastroenterology are reviewed. The endoscopic delivery of light for therapeutic as well as diagnostic purposes is discussed. Current research directions in the field are also indicated where appropriate.

Gastrointestinal laser endoscopy--future horizons

The laser, especially the neodymium:yttrium-aluminum-garnet device, has been a dominant influence on the development of gastrointestinal therapeutic endoscopy. More than 2,000 such procedures were performed in the first 5 years of experience with laser endoscopy at the Mayo Clinic. The major areas for future development are (1) the control of acute and chronic gastrointestinal bleeding, (2) the palliation of malignant gastrointestinal neoplasms, and (3) the management of benign and malignant obstructive lesions of the biliary tract. Refinements in laser devices, delivery systems, and techniques such as photodynamic therapy will be needed to achieve more selective tissue destruction. Improvements in the new adjunctive endoscopic methods of electronic (video) endoscopy and ultrasonography may enhance evolving laser applications by more accurately identifying diseased tissues and guiding their destruction.

Endoscopic laser applications in the gastrointestinal tract

The Nd:YAG and, to a lesser degree, the argon laser have become valuable tools for the surgical endoscopist. Over the last 10 years, the impetus for application of these expensive instruments has changed from what the laser can do to what the laser can do better than less expensive technology. Whereas a few controlled randomized studies suggest that the Nd:YAG laser is better than no therapy and equivalent to other heat-producing instruments for control of upper gastrointestinal bleeding, such studies do not exist for other laser applications. Despite the lack of such studies, we remain convinced that, where available, lasers are the instrument of choice for palliation of unresectable mucosal-based cancers, coagulation of arteriovenous malformations, and ablation of certain adenomatous polyps in selected patients. New techniques on the horizon include the use of endoscopic photo-dynamic therapy for treatment of gastrointestinal cancers and endoscopic laser fragmentation of large common bile duct stones. The potential role for a nonthermal "endoscopic scalpel" is questionable because most gastrointestinal tissues are well vascularized; however, a pulsed laser capable of cutting and coagulation, such as the holmium:YAG laser, may be of some value for incisional endoscopic procedures.