Ralph S. Greco

Bio: Ralph S. Greco is an academic researcher from Stanford University. The author has contributed to research in topics: Catheter & Transplantation. The author has an hindex of 34, co-authored 110 publications receiving 4288 citations. Previous affiliations of Ralph S. Greco include University of Medicine and Dentistry of New Jersey & Rutgers University.

Thromboresistant surface treatment for biomaterials

Abstract: A biomaterial with a thromboresistant surface and a method for forming same are provided. The thromboresistant surface is comprised of a distinct coating layer of a chitosan-based membrane and a bioactive material. The bioactive material is capable of converting the chitosan membrane coating from a highly thrombogenic to an essentially non-thrombogenic one. The bioactive material can be a polymeric substance, such as polyvinyl alcohol, forming a polymeric blend with the chitosan, or, can be a biological substance, such as serum albumin, embedded in or attached to the chitosan membrane which has been activated with a treatment of glutardialdehyde. The thromboresistant biomaterial is suitable for use in vascular grafts having an inside diameter of less than 6 millimeters.

Phase II study to assess the efficacy of conventionally fractionated radiotherapy followed by a stereotactic radiosurgery boost in patients with locally advanced pancreatic cancer

Abstract: Purpose: To determine the efficacy of concurrent 5-fluorouracil (5-FU) and intensity-modulated radiotherapy (IMRT) followed by body stereotactic radiosurgery (SRS) in patients with locally advanced pancreatic cancer. Methods and Materials: In this prospective study, all patients (19) had pathologically confirmed adenocarcinoma and were uniformly staged. Our treatment protocol consisted of 45 Gy IMRT with concurrent 5-FU followed by a 25 Gy SRS boost to the primary tumor. Results: Sixteen patients completed the planned therapy. Two patients experienced Grade 3 toxicity (none had more than Grade 3 toxicity). Fifteen of these 16 patients were free from local progression until death. Median overall survival was 33 weeks. Conclusions: Concurrent IMRT and 5-FU followed by SRS in patients with locally advanced pancreatic cancer results in excellent local control, but does not improve overall survival and is associated with more toxicity than SRS, alone.

Gemcitabine chemotherapy and single-fraction stereotactic body radiotherapy for locally advanced pancreatic cancer

Abstract: Purpose Fractionated radiotherapy and chemotherapy for locally advanced pancreatic cancer achieves only modest local control. This prospective trial evaluated the efficacy of a single fraction of 25 Gy stereotactic body radiotherapy (SBRT) delivered between Cycle 1 and 2 of gemcitabine chemotherapy. Methods and Materials A total of 16 patients with locally advanced, nonmetastatic, pancreatic adenocarcinoma received gemcitabine with SBRT delivered 2 weeks after completion of the first cycle. Gemcitabine was resumed 2 weeks after SBRT and was continued until progression or dose-limiting toxicity. The gross tumor volume, with a 2–3-mm margin, was treated in a single 25-Gy fraction by Cyberknife. Patients were evaluated at 4–6 weeks, 10–12 weeks, and every 3 months after SBRT. Results All 16 patients completed SBRT. A median of four cycles (range one to nine) of chemotherapy was delivered. Three patients (19%) developed local disease progression at 14, 16, and 21 months after SBRT. The median survival was 11.4 months, with 50% of patients alive at 1 year. Patients with normal carbohydrate antigen (CA)19-9 levels either at diagnosis or after Cyberknife SBRT had longer survival ( p p = 0.13). Conclusion SBRT with gemcitabine resulted in comparable survival to conventional chemoradiotherapy and good local control. However, the rate of duodenal ulcer development was significant.

Immunohistochemical profile of the sodium/iodide symporter in thyroid, breast, and other carcinomas using high density tissue microarrays and conventional sections.

Abstract: Extrathyroidal cancers could potentially be targeted with 131 I, if the Na/I symporter (NIS) were functional. Using immunohistochemical methods we probed 1278 human samples with anti-NIS antibody, including 253 thyroid and 169 breast conventional whole tissue sections (CWTS). Four high density tissue microarrays containing a wide variety of breast lesions, normal tissues, and carcinoma cores were tested. The results of the normal microarray were corroborated in 50 CWTS. Nineteen of 34 normal tissues, including bladder, colon, endometrium, kidney, prostate, and pancreas, expressed NIS. Nineteen of 25 carcinomas demonstrated NIS immunopositivity; 55.7% of 479 carcinoma microarray cores expressed NIS, including prostate (74%), ovary (73%), lung (65%), colon (62.6%), and endometrium (56%). NIS protein was present in 75% benign thyroid lesions, 73% thyroid cancers, 30% normalappearing, peritumoral breasts, 88% ductal carcinomas in situ, and 76% invasive breast carcinoma CWTS. Comparatively, breast microarray cores had lower immunoreactivity. Plasma membrane immunopositivity was confirmed in thyrocytes, salivary ductal, gastric mucosa, and lactating mammary cells. In other tissues, immunoreactivity was predominantly intracellular, particularly in malignant lesions. Thus, NIS is present in many normal epithelial tissues and is predominantly expressed intracellularly in many carcinomas. Elucidating the regulatory mechanisms that render NIS functional in extrathyroidal carcinomas may make 131 I therapy feasible. (J Clin Endocrinol Metab 88: 1880 –1888, 2003)

Drug bonded prosthesis and process for producing same

Abstract: There is disclosed an improved prosthesis coated, respectively, with an anionic surfactant, a drug such as an antibiotic and/or antithrombotic agent. Optionally, the coated prosthesis may be treated with an ion exchange compound, to remove un-drug bound anionic surfactant. The drug is bound directly to the surfactant coated prosthesis.

Coated implantable medical device

Abstract: A coated implantable medical device 10 includes a structure 12 adapted for introduction into the vascular system, esophagus, trachea, colon, biliary tract, or urinary tract; at least one layer 18 of a bioactive material positioned over the structure 12; and at least one porous layer 20 positioned over the bioactive material layer 18. Preferably, the structure 12 is a coronary stent, and the bioactive material is at least one of heparin, dexamethasone or a dexamethasone derivative. The device 10 includes layers 18 and 22 of heparin and dexamethasone, the layer 22 of dexamethasone being positioned above the layer 18 of heparin. The layers of bioactive material also can be individual materials or a combination of different materials. Unexpectedly, the more soluble heparin markedly promotes the release of the less soluble dexamethasone above it. The porous layer 20 is composed of a polymer applied by vapor or plasma deposition and provides a controlled release of the bioactive material. It is particularly preferred that the polymer is a polyimide, parylene or a parylene derivative, which is deposited without solvents, heat or catalysts, merely by condensation of a monomer vapor.

A Comparison of Suture Repair with Mesh Repair for Incisional Hernia

Abstract: Background Incisional hernia is an important complication of abdominal surgery. Procedures for the repair of these hernias with sutures and with mesh have been reported, but there is no consensus about which type of procedure is best. Methods Between March 1992 and February 1998, we performed a multicenter trial in which we randomly assigned to suture repair or mesh repair 200 patients who were scheduled to undergo repair of a primary hernia or a first recurrence of hernia at the site of a vertical midline incision of the abdomen of less than 6 cm in length or width. The patients were followed up by physical examination at 1, 6, 12, 18, 24, and 36 months. Recurrence rates and potential risk factors for recurrent incisional hernia were analyzed with the use of life-table methods. Results Among the 154 patients with primary hernias and the 27 patients with first-time recurrent hernias who were eligible for the study, 56 had recurrences during the follow-up period. The three-year cumulative rates of recurren...

Stereotactic body radiation therapy: The report of AAPM Task Group 101

Abstract: Task Group 101 of the AAPM has prepared this report for medical physicists, clinicians, and therapists in order to outline the best practice guidelines for the external-beam radiation therapy technique referred to as stereotactic body radiation therapy (SBRT). The task group report includes a review of the literature to identify reported clinical findings and expected outcomes for this treatment modality. Information is provided for establishing a SBRT program, including protocols, equipment, resources, and QA procedures. Additionally, suggestions for developing consistent documentation for prescribing, reporting, and recording SBRT treatment delivery is provided.