PubMed Health⌕ Search

Biomedical subjects

Phillip Ruiz

Publications and source records attributed to Phillip Ruiz.

At least 55 records · Page 3Linked to original sources
PubMed2004

Viral interleukin-10-engineered autologous hematopoietic stem cell therapy: a novel gene therapy approach to prevent graft rejection.

The Epstein-Barr virus-encoded protein BCRF1 (viral interleukin [vIL]-10) is a biologically active homologue of cellular interleukin (IL)-10. In this study, a novel gene therapy approach to prolong allograft survival was designed. Autologous (syngeneic) hematopoietic progenitor/stem cell-enriched (HSC; lineage(-ve)) population derived from CBA/J mouse bone marrow were transduced with retrovirus encoding vIL-10 gene (vIL-10-HSC), ex vivo; vIL-10-HSC were injected (4-6 x 10(6) cells intravenously) into lethally (9.5 Gy) or sublethally (4 Gy) irradiated CBA/J mice. Six weeks after vIL-10-HSC administration, vascular heterotopic heart (C57BL/6) transplantation was performed. Ex vivo, the vIL-10-HSC produced 5.4 +/- 0.5 ng of vIL-10 protein/2 x 10(5) cells per 24 hr. In vivo, serum vIL-10 production was 187 +/- 205 pg/ml during 3-10 weeks after vIL-10-HSC administration. Cardiac allograft survival was prolonged (p < 0.004) in lethally (71 +/- 40 days) and sublethally (114 +/- 15 days) irradiated mice that received vIL-10-HSC compared to controls that received unengineered (UE) HSC or vector DNA-engineered HSC (12-16 days). However, secondary skin graft (C57BL/6) survival was not prolonged in cardiac allograft-tolerant animals. In the vIL-10-HSC-administered group, graft histopathology demonstrated mild arteritis/venulitis (grade 0.7) and rejection (grade 1.0). Intragraft expression of costimulatory molecules (B7.1, B7.2), cytokines (IL-2, IL-4, mIL-10, interferon [IFN]-gamma), and inducible nitric oxide synthase (iNOS) molecules was markedly lower in vIL-10-HSC-treated tolerant grafts that survived more than 100 days compared to vector DNA-HSC- or UE-HSC-treated controls. Furthermore, T lymphocytes derived from vIL-10-HSC-treated tolerant recipients demonstrated hyporeactivity to donor antigens in mixed lymphocyte cultures. Administration of autologous vIL-10-engineered HSC prior to organ transplantation prolonged cardiac allograft survival significantly.

Animals↗
PubMed2004

Intestinal and multivisceral transplantation after abdominal trauma.

SUMMARY: BACKGROUND Some trauma victims who survive acute illness develop lingering, debilitating syndromes that are incompatible with any semblance of normalcy. Intestinal failure, in particular, exacts a high price in terms of quality of life. Total parenteral nutrition (TPN) has served these patients well, but complications limit its long-term therapeutic effect. Consequently, transplantation is emerging as a life-saving therapy for some patients with the short gut syndrome. METHODS We reviewed eight adult and two pediatric recipients of intestinal and multivisceral transplants after severe abdominal trauma. Background demographics, type of abdominal trauma, transplant procedure, postoperative complications, and survival rates were appraised. This group was also compared with 47 nontrauma recipients of intestinal transplants performed during the same period. RESULTS Four patients (40%) died postoperatively (postoperative days 7, 53, 87, and 91) as a result of multiple organ failure after graft pancreatitis (n = 1), viral encephalitis (n = 1), and sepsis after severe rejection (n = 2). Six patients (60%) are alive (postoperative days 52-1,783). All are off TPN. The 4-year patient survival was 58%, with no significant difference between trauma and nontrauma patients.CONCLUSION Intestinal and multivisceral transplantation are viable options for the treatment of irreversible intestinal failure associated with severe trauma. Surviving patients are TPN independent and have a satisfactory quality of life.

Abdominal Injuries↗
PubMed2004

An analysis of the association between serum citrulline and acute rejection among 26 recipients of intestinal transplant.

Small preliminary studies suggest that serum citrulline levels may act as a marker for acute cellular rejection in small intestinal transplant recipients. The results comparing serum citrulline concentrations with biopsy-based grades of rejection are summarized here for an expanded group of 26 isolated intestinal and multivisceral transplant recipients. Other factors considered included patient and donor age and sex, ischemia time, serum creatinine, and type of transplant. Straight-line fits reasonably described how each patient's citrulline levels changed over time. Among 21 patients who demonstrated increasing citrulline levels over time, the estimated median time-to-achieve normal citrulline (>or=30 micromol/L) was 79 days post-transplant. Using stepwise linear regression, two characteristics were associated with a significantly higher maximum grade of rejection after 14 d post-transplant: longer time-to-achieve normal citrulline (using ranks, p < 0.00001) and the patient not receiving a multivisceral transplant (p = 0.0005). Only the latter characteristic was significantly associated with maximum grade of rejection during the first 14 d post-transplant (p = 0.01). Clearly, time-to-normalization of citrulline was delayed by the incidence of rejection, and in some cases with moderate-to-severe rejection, normalization of citrulline levels never occurred. We plan to further examine the use of citrulline as a marker for rejection in larger prospective studies.

Adult↗
PubMed2003

Anastomotic healing in a small bowel transplantation model in the rat.

Anastomotic healing is impaired after intestinal surgery because of ischemia and reperfusion injury (IRI), which can result in intestinal leaks leading to increased mortality. The objective of this study was to determine the effects of transplant IRI and immune mechanisms on intestinal graft anastomotic healing. Orthotopic intestinal transplantations (OIT) were performed in rats. The experimental design consisted of six groups A-F (n=5/group): A, allogeneic OIT treated with tacrolimus (1 mg/kg/day); B, syngeneic OIT treated with tacrolimus; C, syngeneic OIT; D, allogeneic OIT; E, proximal and distal anastomoses performed in nontransplanted animals; F, same as in group E but treated with tacrolimus. Anastomotic bursting pressure (ABP), hydroxyproline content (HPC), and mucosal inflammatory infiltrate (MII) were determined at the anastomotic sites (proximal and distal) and compared between groups. ABP was significantly (p<0.001) reduced in OIT groups A, B, C, and D compared to control groups E and F at both the proximal and distal anastomotic sites. HPC was approximately 1 microg/mg of tissue in groups A, B, C, and D, and approximately 5 microg/mg of tissue in groups E and F. This demonstrates a significant (p<0.001) reduction in HPC after OIT. MII was significantly (p<0.001) increased in OIT groups when compared to nontransplanted control groups. MII was also significantly (p<0.05) increased in allogeneic OIT groups A and D compared to syngeneic OIT groups B and C. Generally, ABP and HPC were inversely proportional to MII in both nontransplanted control and OIT groups. Reduced anastomotic strength was demonstrated in both syngeneic and allogeneic OIT anastomotic sites irrespective of immunosuppressive therapy, and is probably related to IRI.

Anastomosis, Surgical↗
PubMed2003

Rho kinase promotes alloimmune responses by regulating the proliferation and structure of T cells.

Coordinated rearrangements of the actin-myosin cytoskeleton facilitate early and late events in T cell activation and signal transduction. As many important features of cell shape rearrangement involve small GTP-binding proteins, we examined the contribution of Rho kinase to the functions of mature T cells. Inhibitors of the Rho kinase pathway all had similar actions to inhibit the proliferation of primary lymphocyte cultures. Likewise, transfection of the human Jurkat T cell line with a dominant negative, kinase-defective mutant of Rho kinase diminished Jurkat cell proliferation. Furthermore, inhibition of Rho kinase substantially attenuated the program of cytokine gene expression that characterizes T cell activation, blocked actomyosin polymerization, and prevented aggregation of the TCR/CD3 complex colocalized with lipid rafts. These actions are relevant to immune responses in vivo, as treatment with a Rho kinase inhibitor considerably prolonged the survival of fully allogeneic heart transplants in mice and diminished intragraft expression of cytokine mRNAs. Thus, Rho GTPases acting through Rho kinase play a unique role in T cell activation during cellular immune responses by promoting structural rearrangements that are critical for T cell signaling.

Actins↗
PubMed2003

Transplantation of the abdominal wall.

BACKGROUND: Closure of the abdomen in patients undergoing intestinal transplantation can be extremely difficult, if not impossible. We describe our initial experience with abdominal wall allotransplantation to facilitate abdominal closure. METHODS: We undertook nine cadaveric abdominal wall composite allograft transplants in eight patients. The graft's blood supply was based on the inferior epigastric vessels left in continuity with the donor femoral and iliac vessels. Skin biopsies were undertaken randomly and when rejection was suspected. Vessel patency was monitored by doppler ultrasound. FINDINGS: Six patients have survived, five of whom have intact, viable abdominal wall grafts. Two patients have had a clinically mild episode of acute rejection of the skin of the abdominal wall that resolved with corticosteroid therapy. No clinically apparent graft-versus-host disease has been noted. INTERPRETATION: Transplantation of an abdominal wall composite allograft can facilitate reconstruction and closure of the abdominal compartment in intestinal transplant recipients with complex abdominal wall defects.

Abdominal Wall↗
PubMed2003

Benefit of theophylline administration in tacrolimus-induced nephrotoxicity in rats.

Tacrolimus (TAC), a widely used nephrotoxic calcineurin inhibitor, is associated with renal vasoconstriction possibly through adenosine receptor activation. Theophylline (THEO), an adenosine receptor inhibitor, protects against the nephrotoxicity of drugs associated with renal vasoconstriction. We hypothesized that coadministration of low dose THEO in rats would prevent TAC-induced nephrotoxicity. Sprague-Dawley rats pair-fed a low-sodium diet were randomized into three groups ( n=10/group): the control (CONTROL) group received the vehicle for both medications; the TAC group received TAC 6 mg/kg/day and vehicle; and the TAC+THEO group received TAC and THEO 17 mg/kg/day. On day 21, a timed urine collection was obtained for creatinine clearance. On day 22, serum creatinine, THEO and whole blood TAC concentrations were determined. One kidney was removed for formalin fixation and histological assessment. In the TAC group, serum creatinine increased while creatinine clearance decreased compared to CONTROL (0.3+/-0.0 vs. 0.4+/-0.0 mg/dl and 0.53+/-0.06 vs. 0.34+/-0.04 ml/min/100 g body weight respectively, p<0.05), while TAC+THEO did not differ from control. There were no significant differences in renal histology. Concurrent administration of low-dose THEO prevented the TAC-induced decline in renal function, consistent with a role for adenosine in TAC-induced nephrotoxicity.

Adenosine↗
PubMed2003

Alemtuzumab (Campath-1H) combined with tacrolimus in intestinal and multivisceral transplantation.

BACKGROUND: We combined alemtuzumab (Campath-1H, Berlex Laboratories, Montville, NJ) and tacrolimus (Tac) immunosuppression for intestinal and multivisceral transplantation. MATERIALS AND METHODS: A total of 21 adult patients received 24 grafts: 14 intestinal, nine multivisceral, and one liver-intestinal graft. Alemtuzumab was administered perioperatively in four doses with low-dose Tac (levels 10-15 ng/dL) and no maintenance steroids. Tac was substituted with sirolimus in case of Tac-related complications. Suspected or mild rejections were treated with steroids. Moderate rejections were treated with steroids or OKT3. Severe rejections were treated with OKT3. RESULTS: Of the 16 patients that were followed up for an average of 9 months, 12 are alive with functioning grafts. Two patients experienced severe rejection, three experienced moderate rejection episodes, and seven experienced mild acute rejection episodes. Four patients never developed acute rejection. Infectious complications included a cytomegalovirus enteritis and four fungal infections (related to central venous access). CONCLUSIONS: The combination of alemtuzumab and Tac therapy without steroid use seems to efficiently prevent acute rejection in a significant number of patients without causing frequent opportunistic infections.

Adult↗
PubMed2003

Expression of MUC2 and MUC4 proteins and cytokines: early markers of intestinal graft rejection.

BACKGROUND: Histopathologic examination (HP) is the primary method of monitoring intestinal graft rejection. Alterations in mucin levels have been demonstrated in bowel diseases. The aim of this study was to detect early markers of intestinal graft rejection based on mucin and cytokine levels. METHODS: Allogeneic and syngeneic orthotopic intestinal transplantations were performed in untreated Lewis strain recipient rats from Dark Agouti and Lewis strain donors, respectively (unmodified rejection and nonrejection groups). Similarly, allogeneic and syngeneic orthotopic intestinal transplantations were performed in tacrolimus (immunosuppression)-treated groups. HP was performed on hematoxylin-eosin and periodic acid Schiff-stained sections. Expression of MUC2 and MUC4 proteins and of mRNA was detected by immunohistochemistry and Northern analysis, respectively. Interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and transforming growth factor-beta(1) were measured by reverse transcription-polymerase chain reaction. RESULTS: HP revealed early or mild rejection on day 3, moderate rejection on day 5, and severe rejection on day 7 posttransplantation (posttx) in the unmodified rejection group. A significant (P<0.01) increase in MUC2 and MUC4 expression was observed on day 3 posttx in the allogeneic rejection group compared with syngeneic controls; the levels decreased by day 7. Goblet cells were significantly more frequent on day 3 compared with days 5 and 7 posttx (P<0.01). IFN-gamma and TNF-alpha expression were also higher in the rejection group. CONCLUSIONS: Early transplant rejection is associated with increased MUC2, MUC4, IFN-gamma, and TNF-alpha expression. These markers combined with HP may assist in the diagnosis of early intestinal graft rejection.

Animals↗
PubMed2003

Preliminary experience with campath 1H (C1H) in intestinal and liver transplantation.

BACKGROUND: The aim of this research was to study the efficacy of campath 1H in combination with low-dose tacrolimus immunosuppression for intestinal, multivisceral, and liver transplantation. METHODS: Campath 1H (0.3 mg/kg) was administered in four doses: Preoperatively, at the completion of the transplant, and on postoperative days 3 and 7. Tacrolimus levels were maintained between 5 to 10 ng/dL. Suspected or mild rejections were treated with steroids. Moderate or severe rejections were treated with OKT3. PATIENTS: We studied three groups of patients: adult recipients of intestinal or multivisceral transplants, high-risk pediatric recipients of small-bowel or multivisceral grafts, and adult liver-transplant recipients. RESULTS: Twenty-one adult intestinal recipients received 24 grafts. With follow-up of 2.4 to 16 months, 14 patients are alive and 14 grafts are functioning. Eleven high-risk pediatric intestinal recipients received 12 grafts. There were four mortalities in this group, and after a follow up of 1 to 8.5 months, four patients have not experienced a rejection episode. Five adult liver recipients received five grafts. With a follow-up of 3 to 6.2 months, all five patients are alive. There were no rejection episodes in this group, and none of them required steroid therapy. CONCLUSIONS: This immunosuppressive regimen allows for the avoidance of maintenance adjuvant-steroid treatment in the majority of our patients. Our preliminary data show a trend toward a reduction of the incidence and the severity of rejection episodes, although we need to follow-up larger numbers of patients to confirm these results.

Adult↗
PubMed2003

Use of liver grafts from donors positive for antihepatitis B-core antibody (anti-HBc) in the era of prophylaxis with hepatitis-B immunoglobulin and lamivudine.

BACKGROUND: The increasing demand for transplantation has resulted in a trend toward using virologically compromised donors. We reviewed our experience with liver grafts from hepatitis-B surface antigen (HBsAg)(-), antibody to core antigen (anti-HBc)(+) donors. METHODS: Sixty-two liver transplants using HBsAg(-), anti-HBc(+) donors were studied. The decision to use prophylaxis was based on the presence or absence of donor and recipient risk factors for posttransplant hepatitis-B virus (HBV) transmission or reinfection. If the donor or recipient showed positive HBVDNA, hepatitis-B immunoglobulin (HBIg) and lamivudine were used. If both donor and recipient HBVDNA were negative, a choice between lamivudine and no prophylaxis was made on the basis of presence or absence of HBsAg and antibody to the surface antigen (anti-HBs) in the recipient. RESULTS: No death or graft loss could be ascribed to HBV. Mild HBV infection occurred in two patients who were not taking the recommended prophylaxis. Among the other 60 patients, 1 showed positive e antigen (HBeAg) early after transplantation, and 2 (1 with recurrent cancer, 1 with HIV infection) showed HBsAg(+). None of the three patients had any other evidence of HBV infection. Forty-seven patients underwent liver biopsies. Changes consistent with hepatitis were observed in 26, and 24 had HCV infection; immunostains for HBV antigens were negative in all cases, and 7 showed positive HBVDNA. CONCLUSIONS: A selective protocol based on donor and recipient risk factors for post-liver transplant HBV infection can prevent hepatitis-B infection and avoid unnecessary administration of antiviral prophylaxis in recipients of HBsAg(-), anti-HBc(+) liver allografts.

Adult↗
PubMed2003

Partial abdominal evisceration, ex vivo resection, and intestinal autotransplantation for the treatment of pathologic lesions of the root of the mesentery.

BACKGROUND: Resection of lesions of the root of the mesentery with established techniques is difficult and at times impossible because of their proximity to the blood supply of the intestine. Damage of the superior mesenteric vessels necessitates resection of the intestine, resulting in short bowel syndrome and intestinal failure. STUDY DESIGN: We describe a surgical technique drawn from our experience in intestinal transplantation in which the root of the mesentery (including the lesion) and the head or the entire pancreas, duodenum, small intestine, and part of the colon are excised en bloc and preserved in a cold solution. Resection of the lesion is performed in a bloodless field ex vivo, and the salvaged intestine is reimplanted in the abdominal cavity. We performed this procedure in four patients, two adult and two pediatric, who had extensive neoplasms of the root of the mesentery. Their underlying diseases were mesenteric fibroma, vascular dysplasia of the root of the mesentery, pancreatic cancer, and desmoid tumor. RESULTS: Local control of the lesions was achieved in all four cases, preserving at the same time enough small intestine to avoid short bowel syndrome. All patients survived the operation and live on enteral nutrition 6 to 49.5 months after the procedure. CONCLUSIONS: The procedure of partial abdominal exenteration, ex vivo resection, and autotransplantation is an extension of our experience with intestinal transplantation. In selected cases, this technique may be useful in the treatment of extensive, otherwise unresectable lesions of the root of the mesentery.

Abdominal Pain↗
PubMed2003

Adenovirus infection in pediatric liver and intestinal transplant recipients: utility of DNA detection by PCR.

To evaluate the incidence of adenovirus (AdV) infection in pediatric liver and intestinal transplant recipients, the records of patients with possible AdV infection were reviewed for demographic data, symptomatology, methods of diagnosis, treatment and outcome. To evaluate the impact of polymerase chain reaction (PCR) amplification and identification of AdV DNA as a diagnostic test, the incidence and outcome of AdV before and after the introduction of PCR were compared. Adenovirus infection was identified in 4.1% of liver recipients and 20.8% of intestinal transplant recipients. The overall incidence of AdV did not increase over time, even following the introduction of PCR for virus detection. The higher incidence of AdV in the pediatric intestinal transplant recipients may be attributed to the frequent application of PCR methodology to intestinal biopsy material. Detection of AdV by PCR was associated with reduced mortality compared with detection by culture, either because of earlier detection of invasive disease or because PCR detects the presence of latent as well as active AdV.

Adenoviridae↗
PubMed2003

Inhibition of prolyl-4-hydroxylase ameliorates chronic rejection of mouse kidney allografts.

Interstitial fibrosis, glomerulosclerosis and arteriosclerosis are the major components of chronic allograft nephropathy (CAN), the leading cause of late graft failure after transplantation. To investigate the mechanism of collagen deposition in CAN, we studied the effects of prolyl-hydroxylase inhibitor (PHI), an enzyme essential for collagen formation, using a mouse model of kidney transplantation. Kidneys from H-2b mice were transplanted into MHC-incompatible H-2d recipients (allografts) and at 3 weeks post-transplant, received either PHI or vehicle treatment daily for 3 weeks. At 6 weeks post-transplant, GFR was significantly improved in the allografts receiving PHI (3.3 +/- 0.5 mL/min/kg) compared with those receiving vehicle (1.8 +/- 0.5 mL/min/kg, p < 0.05), while renal function was relatively unimpaired in the nonrejecting isografts (6.45 +/- 0.53 mL/min/kg). Allografts had histologic changes of CAN but the severity was significantly reduced with PHI treatment compared with vehicle, with reductions in interstitial inflammation and fibrosis. Furthermore, TGFâ and connective tissue growth factor mRNA expression was enhanced in both allograft groups compared with the isografts. In conclusion, PHI-treated allografts had improved renal function and reduced the severity of renal injury as a result of CAN. Inhibition of matrix synthesis may be a useful adjunct in ameliorating the development of CAN in humans.

Animals↗
PubMed2003

Mucosal vascular alterations in isolated small-bowel allografts: relationship to humoral sensitization.

Acute vascular rejection (AVR) in human small-bowel transplantation is an inadequately characterized entity whose frequency and severity is not well understood. As compared to severe AVR, changes identifying early, mild or evolving AVR are not known. We created a scoring system to evaluate subtle mucosal vascular changes and examined 188 biopsies from 21 patients obtained in the first 3 months post transplant. A majority of patients had a transient rise in vascular injury, often within 30 days of transplant. Small-vessel congestion and erythrocyte extravasation were the most common alterations. The vascular injury score was not related to acute cellular rejection, HLA type or HLA antigen disparities. However, the patients with the vascular changes had significantly higher peak panel reactive antibodies (PRA) and a higher incidence of positive T-cell and B-cell crossmatch. Finally, graft survival was significantly lower in the patients demonstrating the early vascular lesions. These data suggest that the vascular injury is partially associated with humoral presensitization of the recipient and may be a form of acute vascular rejection. Since these vascular changes are frequent, we advocate early post-transplant monitoring to identify and manage potentially high-risk patients.

Antibodies↗
PubMed2003

The role of intestinal transplantation in the management of babies with extensive gut resections.

BACKGROUND/PURPOSE: Modern neonatal care, surgical treatment, and total parenteral nutrition (TPN) have improved survival rate for babies with extensive gut resections. The authors examined the role of intestinal transplantation in the treatment of these patients. METHODS: The authors reviewed all pediatric intestinal transplants performed for short bowel syndrome at our center (70 transplants performed between Aug 1994 and Feb 2002). Factors affecting patient survival were analyzed. RESULTS: Older patient age at the time of transplant was a significant factor favorably affecting patient survival (P =.031). Trends toward better survival rates were observed in those transplants performed more recently (P =.063), in those patients with greater body weight (P =.084), in those not hospitalized at the time of transplant (P =.14), and in those without concomitant liver failure (P =.12). Three-year survival rate for patients greater than age 2 years and without liver failure was 90%. However, 32% of our recipients underwent transplant at age less than one year, and most in this group (75%) had concomitant liver failure. CONCLUSIONS: For babies with irreversible intestinal failure, intestinal transplantation is a life-saving option. Results, which have recently improved, are best when transplantation compliments more conservative surgical treatments and TPN. However, there is a subset of patients who have liver disease early requiring urgent transplant.

Age Factors↗