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P Ruiz

Publications and source records attributed to P Ruiz.

At least 73 records · Page 4Linked to original sources

Deficiency of 5-lipoxygenase accelerates renal allograft rejection in mice.

Acute renal allograft rejection is associated with alterations in renal arachidonic acid metabolism, including enhanced synthesis of leukotrienes (LTs). LTs, the products of the 5-lipoxygenase (5-LO) pathway, are potent lipid mediators with a broad range of biologic activities. Previous studies, using pharmacological agents to inhibit LT synthesis or activity, have implicated these eicosanoids in transplant rejection. To further investigate the role of LTs in acute graft rejection, we transplanted kidneys from CByD2F1 mice into fully allogeneic 129 mice that carry a targeted mutation in the 5lo gene. Unexpectedly, allograft rejection was significantly accelerated in 5-LO-deficient mice compared with wild-type animals. Despite the marked reduction in graft survival, the 5lo mutation had no effect on the hemodynamics or morphology of the allografts. Although LTB4 levels were reduced, renal thromboxane B2 production and cytokine expression were not altered in 5-LO-deficient allograft recipients. These findings suggest that, along with their proinflammatory actions, metabolites of 5-LO can act to enhance allograft survival.

Animals↗

Serum citrulline and rejection in small bowel transplantation: a preliminary report.

BACKGROUND: There is no known serum marker for intestinal rejection. Serum concentrations of the amino acid citrulline arise almost exclusively from the intestinal mucosa. We examined the impact of acute cellular rejection (ACR) of intestinal allografts on serum citrulline levels. METHODS: Citrulline concentrations were assayed in serum samples of healthy volunteers (n=6) and seven patients who underwent small bowel transplants (SBTx). Trends in mean citrulline concentrations versus degree of ACR were assessed by matching posttransplantation citrulline concentrations with patients' grade of ACR at time of serum collection. Rejection was confirmed by biopsy and graded by following standardized criteria. An additional patient had citrulline concentrations determined for 31 sequential specimens 3-60 days posttransplant. RESULTS: Mean citrulline concentrations in controls were significantly higher than posttransplantation samples at any rejection grade. Mean concentrations declined significantly as rejection severity increased. The overall downward trend was statistically significant (P<0.05). In sequential measurements, citrulline levels increased significantly over time with declining severity of rejection. The increase in mean citrulline concentration between posttransplant days 3-16 and 52-60 was significant (P<0.01). CONCLUSIONS: Serum citrulline levels decline with increasing grade of ACR and may be a useful serum marker for intestinal rejection.

Adult↗

Donor and recipient pretransplant conditioning with nonlethal radiation and antilymphocyte serum improves the graft survival in a rat small bowel transplant model.

BACKGROUND: Lymphoid tissue within the intestinal graft require immunomodulatory strategies to prevent graft versus host disease (GVHD) after transplant. Herein, we evaluate the potential advantage of donor-specific bone marrow infusions in donor and or recipient preconditioned with total body irradiation and or antilymphocyte serum (ALS) on the incidence of GVHD and rejection after small bowel transplantation. METHODS: Heterotopic SBTx was performed from DA to Lewis rats and distributed in nine groups: control group G0 (n=4) and G1 (n=6) without irradiation; recipients in G2 (n=4) were given 400 rd although in groups 3 (n=5), G4 (n=6), G6 (n=5), G7 (n=5), and G8 (n=6) with 250 rd. Donors in G5 (n=4) and G6 were given 250 rd of total body irradiation 2 hours before intestinal retrieval. Donors and recipients in G7 and donors in G8 additionally received ALS (day -5). G1, 2, 3, 5, 6, 7, and 8 were infused with UDBM and G4 with the same amount of TCDBM. Animals received tacrolimus for 15 days and accessed for rejection, GVHD and for chimerism analysis. RESULTS: High mortality due to GVHD was observed in G2, 3, and 4, and correlated with high levels of donor T cells in recipients blood. G0 and G1 showed early acute rejection with progression toward chronic rejection, in contrast to the preconditioned groups. High and low doses of total body irradiation resulted in allogeneic and in a mixed chimerism, respectively. Decrease in donor chimeric cells after 11 weeks in preconditioned groups was correlated with severe allograft rejection. CONCLUSION: Donor preconditioning with 250 rd and or ALS combined with recipient preconditioning and donor-specific bone marrow infusions prevented GVHD and resulted in a transient mixed chimerism with inhibition of allograft rejection after small bowel transplantation.

Animals↗

Apoptosis and rejection in rat intestinal transplantation: correlation with FK506 doses and donor specific bone marrow infusions.

BACKGROUND: Our purpose was to investigate the occurrence and the evolution of apoptosis of enterocytes during acute and chronic rejection in an experimental model of allogeneic heterotopic small bowel transplantation (SBTx). METHODS: Forty-five rats were divided in 10 experimental groups according to the dose of FK506 administration and donor bone marrow infusions (DBMI). Groups 1 and 2 did not received BMI. Groups 3 and 4 received 150x106 cells at day 0, groups 5 and 6 received 75x106 cells at days 0-4, groups 7 and 8 received 75x106 cells at days 4 and 10, and groups 9 and 10 received 30x106 cells at days 4, 10, 15, 20, and 25. Animals of groups 1, 3, 5, 7, and 9 were immunosuppressed with 0.5 mg/kg FK 506, although the remaining groups with 1 mg/kg FK 506, from day 0 to 4 after transplant. Fragment end labeling of DNA was used to detect apoptosis. RESULTS: The number of apoptotic cells detected was highest at day 15 (184+/-154) and then progressively decreased thereafter (day 30=159+/-197; day 45=80+/-167; day 60=0). The number of apoptotic enterocytes was found increased during mild (151+/-108) and moderate (281+/-161) allograft rejection, although a low apoptotic rate was observed in cases without rejection (59+/-13) and during severe (53+/-131) and chronic rejection (46+/-136). Furthermore the number of labeled cells was found inversely correlated with fibrosis (P<0.0001). There was no correlation between apoptosis and the presence or absence of DBMI; however, at day 15 rats receiving 1 mg/day of FK 506 had a significantly lower number of apoptotic cells detected (127+/-103 vs. 233+/-174; P<0.02). CONCLUSIONS: In this study the number of apoptotic cells correlated positively with mild and moderate rejection episodes. In case of severe and chronic rejection a low apoptotic rate was found due probably to extensive necrosis and fibrosis of the mucosa. These data suggest an important role of apoptosis in acute and chronic intestinal rejection in a rat model of intestinal transplantation. Determination of apoptosis in allografts might represent an early sign of small bowel rejection and a useful marker in defining the degree of rejection and its outcome/prognosis.

Animals↗

Complement component C3 is not required for full expression of immune complex glomerulonephritis in MRL/lpr mice.

Complement activation and tissue deposition of complement fragments occur during disease progression in lupus nephritis. Genetic deficiency of some complement components (e.g., Factor B) and infusion of complement inhibitors (e.g., Crry, anti-C5 Ab) protect against inflammatory renal disease. Paradoxically, genetic deficiencies of early components of the classical complement pathway (e.g., C1q, C4, and C2) are associated with an increased incidence of lupus in humans and lupus-like disease in murine knockout strains. Complement protein C3 is the converging point for activation of all three complement pathways and thus plays a critical role in biologic processes mediated by complement activation. To define the role of C3 in lupus nephritis, mice rendered C3 deficient by targeted deletion were backcrossed for eight generations to MRL/lpr mice, a mouse strain that spontaneously develops lupus-like disease. We derived homozygous knockout (C3(-/-)), heterozygous (C3(+/-)), and C3 wild-type (C3(+/+)) MRL/lpr mice. Serum levels of autoantibodies and circulating immune complexes were similar among the three groups. However, there was earlier and significantly greater albuminuria in the C3(-/-) mice compared with the other two groups. Glomerular IgG deposition was also significantly greater in the C3(-/-) mice than in the other two groups, although overall pathologic renal scores were similar. These results indicate that C3 and/or activation of C3 is not required for full expression of immune complex renal disease in MRL/lpr mice and may in fact play a beneficial role via clearance of immune complexes.

Albuminuria↗

Differential kinetics of intracellular caspase-1-like and caspase-3-like enzyme activity in human alloreactive CD4(+) and CD8(+) T cells undergoing apoptosis.

The ICE-like families of serine proteases (caspases) have integral roles in apoptosis. These studies were performed to further understand the role of two critical caspases in relation to apoptotic regulation of the alloimmune response. A novel three-color cytofluorographic technique was utilized for measuring intracellular (in situ) caspase-1-like and caspase-3-like enzyme activity in responding CD4(+) and CD8(+) T cells over several time points of human mixed lymphocyte reactions (MLR). We found that activity levels of caspase 3 in both CD4(+) and CD8(+) responder cells began rising at day 10 of the MLR and peaked at day 14. By comparison, caspase 1 demonstrated the highest activity at day 7 in both cell subpopulations. These results coincided with the appearance of apoptotic cells among the alloreactive cells in the MLR. These findings demonstrate that intracellular caspase-1- and -3-like enzyme activity increases in both CD4(+) and CD8(+) alloreactive T cells as the primary response to allostimulatory cells progresses. While the kinetic profiles for these enzymes differed, both had a temporal association with the appearance of apoptosis in the MLR-generated cells. In all cases, the highest enzyme activity and presence of apoptosis was seen subsequent to the peak proliferative period. These results support the concept that changes in the rate and amount of apoptosis in alloreactive T cells is one mechanism by which the response to alloantigens is attenuated (i.e., tolerance) or sustained.

Apoptosis↗

Long-term survival of rat cardiac allografts by intrathymic plus portal venous injections of donor bone marrow cells and short-term tacrolimus immunosuppression.

Intrathymic (IT) or portal venous (PV) injection of donor antigens has been shown to prolong organ acceptance in low responder rat strain combinations. We determined whether a combination of these strategies would prolong cardiac allograft survival in high responder combinations. Wistar Furth rats received 1 x 10(8) ACI rat bone marrow cells (BMCs) via IT, intravenous (IV), PV, IV + PV, IT + IV or IT + PV route at the time of ACI cardiac transplantation. Without tacrolimus (FK), all grafts were acutely rejected. With FK immunosuppression (1.5 mg/kg per day, I. M., days 0-4), single BMC injection did not increase graft survival beyond 93 days, whereas 70% of grafts survived indefinitely ( > 150 days) when IT and PV BMCs were combined. Animals receiving IT and PV BMCs also had less allograft vasculopathy. Thus, IT and PV injections of donor BMCs under a brief course of FK synergistically improve cardiac allograft survival.

Animals↗

Herpes simplex colitis in a child with combined liver and small bowel transplant.

Herpes simplex virus (HSV) has been a rare cause of gastrointestinal (GI) infection, especially in immunocompromised patients. A variety of GI sites may be involved; however, only three reported cases of HSV colitis have been documented in the literature. To our knowledge, this is the first report of HSV colitis in a small bowel transplant recipient.

Colitis↗

A radiation hybrid transcript map of the mouse genome.

Expressed-sequence tag (EST) maps are an adjunct to sequence-based analytical methods of gene detection and localization for those species for which such data are available, and provide anchors for high-density homology and orthology mapping in species for which large-scale sequencing has yet to be done. Species for which radiation hybrid-based transcript maps have been established include human, rat, mouse, dog, cat and zebrafish. We have established a comprehensive first-generation-placement radiation hybrid map of the mouse consisting of 5,904 mapped markers (3,993 ESTs and 1,911 sequence-tagged sites (STSs)). The mapped ESTs, which often originate from small-EST clusters, are enriched for genes expressed during early mouse embryogenesis and are probably different from those localized in humans. We have confirmed by in situ hybridization that even singleton ESTs, which are usually not retained for mapping studies, may represent bona fide transcribed sequences. Our studies on mouse chromosomes 12 and 14 orthologous to human chromosome 14 show the power of our radiation hybrid map as a predictive tool for orthology mapping in humans.

Animals↗

Graft survival in pediatric liver transplantation.

BACKGROUND/PURPOSE: Liver transplantation is standard therapy for children with a variety of liver diseases. The current shortage of organ donors has led to aggressive use of reduced or split grafts and living-related donors to provide timely liver transplants to these children. The purpose of this study is to examine the impact of these techniques on graft survival in children currently treated with liver transplantation. METHODS: Data were obtained on all patients less than 21 years of age treated with isolated liver transplants performed after January 1, 1996 in an integrated statewide pediatric liver transplant program, which encompasses 2 high-volume centers. Nonparametric tests of association and life table analysis were used to analyze these data (SAS v 6.12). RESULTS: One hundred twenty-three children received 147 grafts (62 at the University of Florida, 85 at the University of Miami). Fifty-two (36%) children were less than 1 year of age at time of transplant, and 80 (55%) were less than 2 years of age. Patient survival rate was identical in the 2 centers (1-year actuarial survival rate, 88.4% and 87.1%). Twenty-five (17%) grafts were reduced, 28 (19%) were split, 6 were from living donors (4%), and 88 (60%) were whole organs. One-year graft survival rate was 80% for whole grafts, 71.6% for reduced grafts, and 64.3% for split grafts (P =.06). Children who received whole organs (mean age, 6.1 years) were older than those who received segmental grafts (mean age, 2.5 years; P <.01). Multifactorial analysis suggested that patient age, gender, and use of the graft for retransplant did not influence graft survival, nor did the type of graft used influence patient survival. CONCLUSIONS: The survival rate of children after liver transplantation is excellent independent of graft type. Use of current techniques to split grafts between 2 recipients is associated with an increased graft loss and need for retransplantation. Improvement in graft survival of these organs could reduce the morbidity and cost of liver transplantation significantly in children.

Age Distribution↗

Intestinal transplantation for the treatment of desmoid tumors associated with familial adenomatous polyposis.

BACKGROUND: Desmoid tumors associated with familial adenomatous polyposis (FAP) are locally invasive. Often occurring in the mesentery of the intestine, they sometimes recur after resection. Complications can include intestinal failure and dependence on parenteral nutrition. We describe 9 patients who underwent intestinal transplantation for the treatment of desmoid tumors associated with FAP. METHODS: Records of patients undergoing intestinal transplantation for desmoid tumors at 2 transplant centers were reviewed for patient age, sex, type of graft, procedure date, tumor site, desmoid complications, medications, extracolonic manifestations, status at follow-up, and length of survival. RESULTS: Nine patients with FAP and intestinal failure caused by desmoid tumors were treated with isolated intestinal (n = 6), multivisceral (n = 2), or combined liver-intestinal transplantation (n = 1). Desmoid tumors recurred in the abdominal walls of 2 patients. Two patients died: one as a result of sepsis, the other because of a rupture of a mycotic aneurysm of the aortic anastomosis. One graft lost to severe rejection was replaced with a second intestinal graft. Eleven to 53 months after transplantation, 7 patients were alive, well, independent of parenteral treatment, and leading apparently normal lifestyles. CONCLUSIONS: Transplantation of the intestine alone or as part of a multivisceral transplantation may help rescue otherwise untreatable patients with complicated desmoid tumors.

Adenomatous Polyposis Coli↗

Thrombocytopenia in HIV-infected drug users in the HAART era.

The present case-control study compared 26 HIV+ drug users having persistent thrombocytopenia (TCP<150 000/mm(3)) with 54 available age, gender and HIV CDC classification matched controls with normal platelet counts. Participants were followed longitudinally over a 2-year period (1998-2000), and hematological alterations evaluated in relationship to antiretroviral treatment, drug use and nutritional (selenium) status. Demographic information and medical history, including antiretroviral treatment were obtained. Blood was drawn for complete cell blood count, T lymphocytes and viral load. Sixty-nine percent of the individuals with persistent TCP and 49% of the controls were receiving antiretrovirals. At baseline, no significant differences in CD4 existed between the two groups. Over time, CD4 cell count declined in the cases (P = 0.05) and a significantly higher proportion of the cases (38%) developed AIDS (CD4<200 cell/mm(3)), as compared to the controls (18%, P = 0.004). A high risk for development of thrombocytopenia was observed with specific drug use (heroin 2.96 times, P = 0.0007), selenium levels below 145 microg/l (6 times, P = 0.008), and abnormal liver enzyme (SGOT) levels (2 times, P = 0.002). Together, these results indicate a number of factors that may be sensitive predictors of thrombocytopenia, which, despite antiretroviral treatment, appears to be related to more rapid disease progression in drug users.

Adult↗

Enhancement of splenic-macrophage Fcgamma receptor expression by treatment with estrogens.

Splenic-macrophage Fcgamma receptors (FcgammaRs) participate in the pathophysiologies of immune-complex diseases and in host defense against infection. Modulation of macrophage FcgammaR expression is an immuno-therapeutic target. Glucocorticoids, sex steroids, and dopaminergic drugs modulate macrophage FcgammaR expression. Previous data indicate that estradiol increases macrophage FcgammaR expression. Nevertheless, the effects of clinically used estrogens upon macrophage FcgammaR expression are unknown. We assessed the effects of treatment with commonly used estrogens on the expression of macrophage FcgammaRs using a guinea pig experimental model. Six estrogens have been studied: ethynylestradiol (Et), mestranol (M), chlortianisene (Ct), promestriene, 17-epiestriol, and 17beta-estradiol. Following in vivo treatment of guinea pigs, we determined the clearance of immunoglobulin G (IgG)-sensitized erythrocytes in vivo, the binding of IgG-sensitized erythrocytes by isolated splenic macrophages, and splenic-macrophage FcgammaR cell surface expression. Estrogens enhance the clearance of IgG-sensitized erythrocytes by increasing splenic-macrophage FcgammaR expression. Et, M, and Ct were more effective than the other estrogens. Flow cytometry and fluorescence microscopy with monoclonal antibodies demonstrated that estrogens increase the cell surface expression of FcgammaR1 and -2 more than that of FcgammaR2. These data indicate that treatment with commonly used estrogens enhances the clearance of IgG-sensitized cells by improving splenic-macrophage FcgammaR expression.

Animals↗