Ovalbumin serves as a neo-transplantation antigen in retinal pigment epithelial cells.

PURPOSE: Our long-term goal is to determine the optimal methods for inducing allograft tolerance to facilitate transplantation of retinal pigment epithelial cells or stem cells for the treatment of retinal degenerative diseases. These goals have been hampered by the extreme complexity of allograft rejection and the heterogeneity of responding T cells. The current studies were undertaken to develop a simplified transplant model for studying rejection and tolerance in the unique environment of the eye. METHODS: To provide a defined transplantation antigen, transgenic C57BL/6 (B6) mice were produced, which express the exogenous chicken egg ovalbumin (OVA) gene under the regulation of the mouse tyrosinase related protein-1 (TRP-1) promoter that is transcriptionally active in retinal pigmented epithelial (RPE) cells. To determine whether the transgene was expressed as a neo-transplantation antigen, RPE from TRP-1-OVA mice were injected into the subretinal space of B6 mice or B6 mice expressing the OVA-specific (OT1) TCR transgenes and examined for inflammatory cell infiltration. RESULTS: The TRP-1-OVA transgenic mice expressed OVA mRNA in the brain and eye but not the heart or kidney. RPE cells from TRP-1-OVA transgenic mice expressed mRNA and protein encoded by the OVA gene and RPE expressing TRP-1-OVA induced an inflammatory response within the subretinal space of OT1 mice but not in B6 mice. CONCLUSIONS: OVA serves as a defined, neo-transplantation antigen in RPE that is recognized by mice whose CD8+ T cells recognize OVA peptide. These observations provide new tools for future studies of the mechanisms of rejection and prolongation of RPE transplants in the eye.

Effect of high-dose steroids on anastomotic complications after proctocolectomy with ileal pouch-anal anastomosis.

This review was designed to determine whether "high-dose" steroid therapy (> or =20 mg prednisone/day) increases the likelihood of anastomotic complications after restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). The hospital records of 100 patients undergoing proctocolectomy with IPAA were reviewed. Patient characteristics were analyzed to determine what factors were associated with higher rates of anastomosis-related complications. Seventy-one of our patients were given diverting ileostomies, whereas the remaining 29 underwent a single-stage procedure. Fifty-four percent of the patients in our review were taking steroids preoperatively, 39 of whom were on high-dose therapy. The overall anastomosis-related complication rate was 14%. There was no significant difference in complication rates with respect to age, steroid use, steroid dose, use of a diverting ileostomy, type of anastomosis, duration of disease, or presence of backwash ileitis. A trend toward higher leakage rates was found in patients undergoing single-stage procedures (10.3% vs. 2.8%, P=0.14) as well as in patients undergoing single-stage procedures on high-dose steroids (22% vs. 5.0, P=0.22). Nevertheless, neither of these trends was found to be statistically significant, which was likely influenced by the small sample size. Our data suggest that there may be an increase in anastomotic leakage rates in patients on high-dose steroids undergoing a single-stage proctocolectomy with IPAA. Nevertheless, our rate was not as high as the rates seen by other investigators and did not reach statistical significance. During preoperative counseling, patients on high-dose steroids should be informed of this uncertain but real risk of anastomotic leakage.

Internet use by colorectal surgery patients: a surgeon's tool for education and marketing.

The goal of this study is to understand the role of the Internet in the education and recruitment of patients within colorectal surgery practices. Surveys of Internet use were completed by 298 patients visiting five outpatient colorectal surgery clinics affiliated with the University of Southern California. Data collected included the patient's age, gender, level of education, zip code at home, type of clinic visited, and information on the respondent's Internet use. Overall, 20 per cent of the respondent patients visiting our clinics had used the Internet to research the medical condition that prompted their visit. Highest grade level completed (P < 0.001), age (P < 0.01), type of clinic (P < 0.001), and household income (P < 0.001) were all found to be associated with any prior use of the Internet whereas gender was not (P = 0.58). Among Internet users, only household income and frequent use of the Internet were associated with searching the Internet for medical information (P < 0.001). Ultimately, all of the Internet-using patients surveyed felt the medical information they found was "some what" or "very helpful." Understanding which patients "go online" to search for medical information is essential for surgeons who wish to use the Internet for marketing their practices and educating their patients.

Effects of housing density in five inbred strains of mice.

To evaluate the effect of increased mouse density in a cage, mice were housed at the density recommended by the 1996 Guide for the Care and Use of Laboratory Animals and at densities that were approximately 2, 2.6, and 3 times greater. Five strains of mice (129S1/SvImJ, A/J, BALB/cByJ, C57BL/6J, and DBA/2J) were evaluated throughout 3- and 8-month timeframes for health and well-being, including mortality, cardiac measures, plasma cholesterol, body weight, bone mineral density, organ weights, hematology, behavioral observations, and open field and light-dark tests. For 22 of the 27 traits measured, increased housing density had no significant effect. Kidney weight, adrenal weight, and heart rate decreased as mice were housed more densely, and some of the decreases were statistically significant. Reduced kidney weight, adrenal weight, and heart rate are not considered to be negative outcomes and may even indicate reduced stress. However, all measurements of these three traits were within normal physiological ranges. Percent fat increased slightly in strains 129S1/SvImJ, A/J, and DBA/2J, but did not increase in strains BALB/cByJ, and C57BL/6J. These results indicate that mice can be housed at higher densities than those currently recommended.

The management of complicated diverticulitis and the role of computed tomography.

PURPOSE: Acute diverticulitis is a disease with a wide clinical spectrum, ranging from a phlegmon (stage Ia), to localized abscesses (stages Ib and II), to free perforation with purulent (stage III) or feculent peritonitis (stage IV). While there is little debate about the best treatment for mild episodes and/or very severe episodes, uncertainty persists about the optimal management for intermediate stages (Ib and II). The aim of our study was therefore to define the role of computed tomography (CT) and to analyze its impact on the management of acute diverticulitis. METHODS: We retrospectively analyzed 511 patients (296 males, 215 females) admitted for acute diverticulitis between January 1994 and December 2003. Excluded were patients with stoma reversal only, "diverticulitis" mimicked by cancer, or significantly deficient patient records. Patients were analyzed either as a whole or subgrouped according to age (<40 yr, >40 yr). A modified Hinchey classification was used to stage the severity of acute diverticulitis. RESULTS: In 99 patients (19.4%), an abscess was found (74 pericolic, 25 pelvic, median diameter: 4.0 cm). CT-guided drainage was performed in 16 patients, one failure requiring a two-stage operation. Whereas conservative treatment failed in 6.8% in patients without abscess or perforation, 22.2% of patients with an abscess required an urgent resection (68.2%, one-stage, 31.8%, two-stage). Recurrence rates were 13% for mild cases, as compared to 41.2% in patients with a pelvic abscess (stage II) treated conservatively with/without CT-guided drainage. Of all surgical cases, resection/primary anastomosis was achieved in 73.6% with perioperative mortality of 1.1% and leak rate was 2.1%. CONCLUSIONS: CT evidence of a diverticular abscess has a prognostic impact as it correlates with a high risk of failure from nonoperative management regardless of the patient's age. After treatment of diverticulitis with CT evidence of an abscess, physicians should strongly consider elective surgery in order to prevent recurrent diverticulitis.

gammadelta T-cell clones from intestinal intraepithelial lymphocytes inhibit development of CTL responses ex vivo.

Oral administration of antigen induces a state of tolerance that is associated with activation of CD8+ T cells that can transfer unresponsiveness to naïve syngeneic hosts. These T cells are not lytic, but they inhibit development of antibody, CD4+ T helper cell, and CD8+ cytotoxic T lymphocyte (CTL) responses upon adoptive transfer into naïve, syngeneic mice. In addition, we have shown that depletion of gammadelta T cells by injection of the anti-delta chain antibody (GL3) down modulates the expression of gammadelta T-cell receptor (TCR) and inhibits the induction of oral tolerance to ovalbumin. Oral administration of antigen also fails to induce tolerance in TCR delta-chain knockout mice suggesting that gammadelta T cells play a critical, active role in tolerance induced by orally administered antigen. To further study the contribution of gammadelta T cells to tolerance, murine gammadelta T cells were isolated from intraepithelial lymphocytes (IEL) of the small intestine by stimulation with splenic filler cells, concanavalin A and growth factors. gammadelta IEL lines demonstrated lytic activity in a redirected lysis assay. gammadelta T-cell clones express different gammadelta TCR genes and secrete large amounts of interleukin (IL)-10, but little or no IL-2, IL-4, or interferon-gamma. gammadelta IEL clones expressed transforming growth factor-beta1 and macrophage migration inhibitory factor, as well as IL-10, mRNA. Moreover, gammadelta T-cell clones potently inhibited the generation of CTL responses by secreted molecules rather than by direct cell-to-cell contact.

Management of retained colorectal foreign bodies: predictors of operative intervention.

PURPOSE: This study was designed to review experience at our hospital with retained colorectal foreign bodies. METHODS: We reviewed the consultation records at Los Angeles County + University of Southern California General Hospital from October 1993 through October 2002. Ninety-three cases of transanally introduced, retained foreign bodies were identified in 87 patients. Data collected included patient demographics, extraction method, location, size and type of foreign body, and postextraction course. RESULTS: Of 93 cases reviewed, there were 87 individuals who presented with first-time episodes of having a retained colorectal foreign body. For these patients, bedside extraction was successful in 74 percent. Ultimately, 23 patients were taken to the operating room for removal of their foreign body. In total, 17 examinations under anesthesia and 8 laparotomies were performed (2 patients initially underwent an anesthetized examination before laparotomy). In the eight patients who underwent exploratory laparotomy, only one had successful delivery of the foreign object into the rectum for transanal extraction. The remainder required repair of perforated bowel or retrieval of the foreign body via a colotomy. In our review, a majority of cases had objects retained within the rectum; the rest were located in the sigmoid colon. Fifty-five percent of patients (6/11) presenting with a foreign body in the sigmoid colon required operative intervention vs. 24 percent of patients (17/70) with objects in their rectum (P = 0.04). CONCLUSIONS: This is the largest single institution series of retained colorectal foreign bodies. Although foreign objects located in the sigmoid colon can be retrieved at the bedside, these cases are more likely to require operative intervention.