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C Esquivel

Publications and source records attributed to C Esquivel.

At least 19 recordsLinked to original sources
PubMed1998

Cytotoxic isoflavans from Eysenhardtia polystachya.

Two new cytotoxic isoflavans, (3S)-7-hydroxy-2',3',4',5', 8-pentamethoxyisoflavan (1) and (3S)-3',7-dihydroxy-2',4',5', 8-tetramethoxyisoflavan (2), were isolated from the bark and trunks of Eysenhardtia polystachya (Leguminosae), together with the known constituents stigmasterol, isoduartin, cuneatin, 7-hydroxy-2',4', 5'-trimethoxyisoflavone, and 3,4-dimethoxy-8, 9-(methylenedioxy)pterocarpan. The structures of 1 and 2 were elucidated on the basis of spectroscopic methods. The antimicrobial, cytotoxic, and insecticidal potential of some of these compounds were evaluated. The isoflavans 1, 2, and isoduartin (2', 7-dihydroxy-3',4',8-trimethoxyisoflavan) displayed moderate cytotoxic activity against KB cell lines.

Animals↗
PubMed1997

Efficacy of tacrolimus as rescue therapy for chronic rejection in orthotopic liver transplantation: a report of the U.S. Multicenter Liver Study Group.

BACKGROUND: A study was performed by 17 different U.S. liver transplantation centers to determine the safety and efficacy of conversion from cyclosporine to tacrolimus for chronic allograft rejection. METHODS: Ninety-one patients were converted to tacrolimus a mean of 319 days after liver transplantation. The indication for conversion was ongoing chronic rejection confirmed by biochemical and histologic criteria. Patients were followed for a mean of 251 days until the end of the study. RESULTS: Sixty-four patients (70.3%) were alive with their initial hepatic allograft at the conclusion of the study period and were defined as the responder group. Twenty-seven patients (29.7%) failed to respond to treatment, and 20 of them required a second liver graft. The actuarial graft survival for the total patient group was 69.9% and 48.5% at 1 and 2 years, respectively. The actuarial patient survival at 1 and 2 years was 84.4% and 81.2%, respectively. Two significant positive prognostic factors were identified. Patients with a total bilirubin of < or = 10 mg/dl at the time of conversion had a significantly better graft and patient survival than patients converted with a total bilirubin > 10 mg/dl (P=0.00002 and P=0.00125, respectively). The time between liver transplantation and conversion also affected graft and patient survival. Patients converted to tacrolimus < or = 90 days after transplantation had a 1-year actuarial graft and patient survival of 51.9% and 65.9%, respectively, compared with 73.2% and 87.7% for those converted > 90 days after transplantation. The mean total bilirubin level for the responder group was 7.1 mg/dl at the time of conversion and decreased significantly to a mean of 3.4 mg/dl at the end of the study (P=0.0018). Thirteen patients (14.3%) died during the study. Sepsis was the major contributing cause of death in most of these patients. CONCLUSIONS: Our results suggest that conversion to tacrolimus for chronic rejection after orthotopic liver transplantation represents an effective therapeutic option. Conversion to tacrolimus before development of elevated total bilirubin levels showed a significant impact on long-term outcome.

Adolescent↗
PubMed1996

Hepatitis C virus (HCV) genotype analysis in apparently healthy anti-HCV-positive Parisian blood donors.

BACKGROUND: As only a few studies have examined the prevalence of various hepatitis C virus (HCV) subtypes in blood donors, information about the variability and route of infection in apparently healthy persons is limited. STUDY DESIGN AND METHODS: Blood donations collected at a large Parisian hospital (52,441) were investigated for antibodies to HCV. Serum samples were screened with an enzyme immunoassay. All HCV-positive donations were retested with a second enzyme immunoassay and confirmed by immunoblot. The HCV genotype was determined for all polymerase chain reaction-positive subjects. Untypable genotypes were sequenced in the NS5B region. RESULTS: In total, 83 (0.26%) blood donors were anti-HCV positive. Men (0.34%) were significantly more likely to be infected (p < 0.001) than women (0.19%). Prevalence rates in men between 20 and 39 years of age were higher than those in similar women (p = 0.01), but greater in women aged from 50 to 65 years (p = 0.05). Fifty-five sera were viremic, of which 49 could be genotyped by a line probe assay. One new HCV type 1 subtype and three new HCV type 2 subtypes were discovered. In total, 28, 10, 11, 5, and 1 serum samples were grouped into HCV types 1 through 5, respectively, involving a total of 13 subtypes. The mean age of HCV type 2-infected donors was 42 +/- 11 years, but that for type 3-infected subjects was only 30 +/- 4 years (p = 0.0048). Forty-nine subjects showed elevated alanine aminotransferase levels; 39 (80%) of these subjects were viremic (p < 0.05). CONCLUSION: Among the sampled population, an HCV prevalence rate of 0.26 percent was found, with the five most common European genotypes causing the infections. Four new subtypes were discovered. Correlation between genotype and risk factors was not apparent, but links with age, sex, and ethnic origin emerged.

Adult↗
PubMed1995

FK506 (tacrolimus) compared with cyclosporine for primary immunosuppression after pediatric liver transplantation. Results from the U.S. Multicenter Trial.

We report on the efficacy and safety of FK506 (tacrolimus) compared with a cyclosporine (CsA)-based immunosuppressive regimen after 1 year of treatment in pediatric liver allograft recipients (< 12 years) participating in a multicenter U.S. randomized trial. Patients received either FK506 or CsA as primary immunosuppression following a first ABO-compatible liver transplant. Intravenous FK506 was initiated at 0.1 mg/kg per day, followed by oral FK506 beginning at 0.3 mg/kg per day. The dose was adjusted to maintain plasma trough levels of 0.5-2.0 ng/ml. The CsA group was treated according to each center's usual protocol. Both groups received the same initial doses of corticosteroids. All rejection episodes were biopsy-proven and a standardized algorithm was adopted for the treatment of rejection. Thirty patients were randomized to the FK506 group and 20 to the CsA group. After twelve months of follow-up 20 patients remained in the FK506 group and 13 in the CsA group. Patient survivals were 80% and graft survival 70% in the FK506 group compared with 81% and 71% respectively, in the CsA group. 48% of the FK506 group remained rejection-free compared with 21% of the CsA group, and 79% of FK506-treated patients did not require OKT3 compared with 68% of CsA treated patients. The cumulative corticosteroid dose was less at each time point throughout the first year in the FK506 group. The incidence of serious and minor infections was similar in both groups. Nephrotoxicity, neurotoxicity, and gastrointestinal disturbances were the major toxicities reported. Differences did not reach statistical significance between the two groups although major neurologic events, diarrhea and dyspepsia were more often reported in the FK506 group. There was no difference in mean serum creatinine at 12 months between the two groups. There was a tendency toward lower mean serum cholesterol in the FK506 group. There was no hirsuitism in the FK506 group compared with a 30% incidence in the CsA group. In conclusion, compared with CsA, there is a trend toward less rejection in FK506-treated pediatric allograft recipients, while both drugs have a similar spectrum of side effects.

Adrenal Cortex Hormones↗
PubMed1991

Phenotypes of apolipoprotein B and apolipoprotein E after liver transplantation.

Apolipoprotein (apo) E and the two B apolipoproteins, apoB48 and apoB100, are important proteins in human lipoprotein metabolism. Commonly occurring polymorphisms in the genes for apoE and apoB result in amino acid substitutions that produce readily detectable phenotypic differences in these proteins. We studied changes in apoE and apoB phenotypes before and after liver transplantation to gain new insights into apolipoprotein physiology. In all 29 patients that we studied, the postoperative serum apoE phenotype of the recipient, as assessed by isoelectric focusing, converted virtually completely to that of the donor, providing evidence that greater than 90% of the apoE in the plasma is synthesized by the liver. In contrast, the cerebrospinal fluid apoE phenotype did not change to the donor's phenotype after liver transplantation, indicating that most of the apoE in CSF cannot be derived from the plasma pool and therefore must be synthesized locally. The apoB100 phenotype (assessed with immunoassays using monoclonal antibody MB19, an antibody that detects a two-allele polymorphism in apoB) invariably converted to the phenotype of the donor. In four normolipidemic patients, we determined the MB19 phenotype of both the apoB100 and apoB48 in the "chylomicron fraction" isolated from plasma 3 h after a fat-rich meal. Interestingly, the apoB100 in the chylomicron fraction invariably had the phenotype of the donor, indicating that the vast majority of the large, triglyceride-rich apoB100-containing lipoproteins that appear in the plasma after a fat-rich meal are actually VLDL of hepatic origin. The MB19 phenotype of the apoB48 in the plasma chylomicron fraction did not change after liver transplantation, indicating that almost all of the apoB48 in plasma chylomicrons is derived from the intestine. These results were consistent with our immunocytochemical studies on intestinal biopsy specimens of organ donors; using apoB-specific monoclonal antibodies, we found evidence for apoB48, but not apoB100, in donor intestinal biopsy specimens.

Adult↗
PubMed1990

Analysis of hepatic T lymphocyte and immunoglobulin deposits in patients with primary biliary cirrhosis.

The histological findings in patients with primary biliary cirrhosis have been well-defined and are often used in the clinical staging of disease. However, it has only been with the development of reagents that phenotypically characterize the lymphoid infiltrate that attempts have been made to correlate pathophysiology with immune effector populations. Indeed, the inflammatory hepatic lesions in primary biliary cirrhosis have been described as containing CD4-positive and CD8-positive T cells. Less clear, however, have been the T cell receptors in these lesions. Further, the data on immunoglobulin deposits in hepatic lesions have been less well-defined; this deficit may be a result of the quality of polyspecific sera and difficulties in background. To address these issues, we have used a battery of well-defined monospecific and polyspecific reagents to phenotypically define the occurrence of lymphoid cells in the livers of patients undergoing transplantation. Furthermore, we have defined these same markers on T cell lines derived from liver, regional lymph node and peripheral blood. The predominant cell type in the mononuclear infiltrate is the CD3+, CD4+ T lymphocyte bearing the T cell receptor alpha beta. T cell lines from the same patients demonstrate similar findings. Of special importance, however, was the detection of CD20+ B cells and Ig+ cells in the lymphoid infiltrate. Indeed, we also readily demonstrated the presence of immunoglobulin on the surface of biliary epithelium. These data suggest that mechanisms involved in the pathophysiology of primary biliary cirrhosis may include both T cell and antibody mechanisms. The results also underscore the need to develop a functional, and not just a phenotypical, assay of the inflammatory infiltrate.

Antibodies, Monoclonal↗
PubMed1989

Transplantation of multiple abdominal viscera.

Two children with the short-gut syndrome and secondary liver failure were treated with evisceration and transplantation en bloc of the stomach, small intestine, colon, pancreas, and liver. The first patient died perioperatively, but the second lived for more than 6 months before dying of an Epstein-Barr virus-associated lymphoproliferative disorder that caused biliary obstruction and lethal sepsis. There was never evidence of graft rejection or of graft-vs-host disease in the long-surviving child. The constituent organs of the homograft functioned and maintained their morphological integrity throughout the 193 days of survival.

Animals↗
PubMed1989

Mechanisms of hypertension during and after orthotopic liver transplantation in children.

The aim of this study was to assess the hormonal alterations that may mediate the systemic hypertension that develops in patients during the perioperative period of orthotopic liver transplantation. We studied nine pediatric patients without previous hypertension or renal disease during six time points, starting before transplantation and ending at 48 hours after surgery. Hypertension developed in all patients in association with central venous pressures less than 10 mm Hg. Free water clearance was negative in all nine patients. Vasopressin levels increased intraoperatively but fell as hypertension developed. Atrial natriuretic factor levels increased as systemic blood pressure rose. A high level of plasma renin activity was observed in four patients with renal insufficiency. In six patients, postoperative 24-hour urinary norepinephrine excretion was within the normal age-adjusted range. These findings suggest that the combination of cyclosporine, corticosteroids, and, in some patients, an elevated plasma renin activity prevents the kidney from responding to the acute volume and salt overload with an appropriate diuresis and natriuresis, thus leading to systemic hypertension. The treatment of hypertension after liver transplantation may include salt restriction, diuretics, and, in those patients with a low creatinine excretion index, angiotensin coverting enzyme inhibitors.

Adolescent↗
PubMed1989

Evidence of repetitive patterns of chromatin distribution in cell nuclei of rat liver.

Samples of rat livers were fixed in glutaraldehyde, contrasted en bloc with phosphotungstic acid, embedded in an epoxy resin and serially sectioned. The study of three-dimensional models of 20 complete nuclei shows that all of them share some general features: they have more than one nucleolus (2-4), an irregular layer of compact chromatin adjacent to the nuclear membrane and well-delimited clumps of chromatin both in the nuclear sap and surrounding the nucleoli. A space of 8 sections containing the central nucleolus and a lateral one was studied in detail. In this space, 8 clumps of compact chromatin were found in 17 nuclei and 9 clumps in the other 3 nuclei. No other number of clumps was found in those zones. In all the nuclei studied the compact chromatin surrounding the central nucleolus contacts the nuclear envelope. This contact takes place in a region almost diametrically opposed to the lateral nucleolus in 13 nuclei. In 7 nuclei, these structures were at angles between 50 and 125 degrees. These results support the existence of nonrandom repetitive patterns of chromatin distribution in liver cells.

Animals↗