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Biomedical subjects

Benjamin Samstein

Publications and source records attributed to Benjamin Samstein.

8 recordsLinked to original sources

Extended-donor criteria liver allografts.

Extended-donor criteria liver allografts do not meet traditional criteria for transplantation. Although these organs offer immediate expansion of the donor pool, transplantation of extended-donor criteria liver allografts increases potential short- and long-term risk to the recipient. This risk may manifest as impaired allograft function or donor-transmitted disease. Guidelines defining this category of donor, level of acceptable risk, principles of consent, and post-transplantation surveillance have not been defined. This article reviews the utilization, ethical considerations, and outcomes of extended-donor criteria liver allografts.

Donor Selection↗

A critical evaluation of hepatic resection in cirrhosis: optimizing patient selection and outcomes.

Hepatic resection has long been the mainstay of treatment of primary liver cancers, particularly hepatocellular carcinoma (HCC). Because of the high incidence of cirrhosis in patients with HCC, the use of resection was initially limited by the ability of the cirrhotic liver to sustain the surgical insult and the mass reduction. Today, hepatectomy in cirrhosis is undergoing a remarkable evolution. Although surgical and anesthetic improvements have increased the safety of this option, the rapid development of alternative therapies has decreased the need for it. Local excision for small HCC is likely to be replaced by image-guided, percutaneous ablative techniques. Furthermore, total replacement of a cirrhotic liver may be a more effective long-term cure than resection. Unquestionably, resection remains the optimal approach for patients with large tumors and healthy underlying liver function. The role of rapidly evolving new approaches will remain the subject of intensive inquiry in the years to come. In this report, we have attempted to clarify current practice with respect to the evaluation, selection, and technique of resection in cirrhosis, and identify areas of active inquiry.

Carcinoma, Hepatocellular↗

Toll-like receptor-4 and allograft responses.

Signaling through toll-like receptors (TLRs) is believed to be the critical first step in the activation of antigen presenting cells and the initiation of adaptive immune responses. Of these receptors, TLR-4 particularly recognizes endogenous agonists and may be important for allograft responses. We tested this concept using mice with defective function and structure of TLR-4 as recipients of grafts across major and minor histocompatibility barriers. The kinetics of rejection was the same in mutant mice and wild-type controls. Our results highlight an important difference between alloimmune and conventional immune responses.

Animals↗

Physiologic and immunologic hurdles to xenotransplantation.

The major problem in the field of renal transplantation is currently the shortage of available kidneys. However, the use of animals as a source of kidneys, i.e., xenotransplantation, is increasingly being viewed as a potential solution to this problem. One preeminent hurdle to xenotransplantation is the immune response of the recipient against the graft; other hurdles include the physiologic limitations of the transplant, infection, and ethical considerations. This review summarizes what is currently known regarding the obstacles to xenotransplantation and some potential solutions to those problems.

Acute Disease↗

Work Hours Assessment and Monitoring Initiative (WHAMI) under resident direction: a strategy for working within limitations.

PURPOSE: A review of surgical residents' duty-hours prompted a Work Hours Assessment and Monitoring Initiative (WHAMI) that preemptively limits residents from violating "duty-hours rules." METHODS: Work hours data for the Department of Surgery were reviewed over 8-months at New York Presbyterian Hospital-Columbia Campus. This ongoing review is performed by a work-hours monitoring team, which supervises residents' hours for the initial 5-days of each week. As residents approach work-hours limits for the week, they are dismissed from duty for appropriate time periods in the remaining 2 days of the week. RESULTS: The work-hours data entry compliance for 52 residents was increased from 93% to 99% after creation of the WHAMI. Before the new system, a mean of 9.5 residents per month (19%) worked an average of 7.3 +/- 6.4 hours over the 80-hour limit. Averaged monthly compliance with the 80-hour work limit was increased to 98% with introduction of the WHAMI. A review of on-call duty hours revealed a mean of 7 (14%) residents per month who worked an average of 2.4 hours beyond 24-hour call limitations including "sign-out" time imposed by the ACGME. New monitoring procedures have improved compliance to 100% with 24-hour call limitations imposed by the ACGME. Compliance with the more stringent New York State (NYS) guidelines has approached 94% with noncompliant residents extending on-call hours by an average of 1.5 hours over the 24-hour limitations, most on "off General Surgery" rotations or out-of-state rotations. Review of mandatory rest periods contributed to an increase in mean "time off" between work periods, thereby increasing compliance with ACGME guidelines and NYS regulations from 75% to 88%, and 90% to 98%, respectively. Residents reporting less than 10 hours rest reported increased "time off" from 6.2 +/- 2.0 to 7.9 +/- 1.3 hours (p < 0.001). CONCLUSIONS: Internal review of surgical resident's duty-hours at a large university hospital revealed that despite strict scheduling and the requirement of mandatory duty-hours entry, achieving the goals of meeting the duty-hours requirements and of ongoing data entry required the creation of a resident enforced, real-time Work Hours Assessment and Monitoring Initiative.

Follow-Up Studies↗