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Biomedical subjects

C Esquivel

Publications and source records attributed to C Esquivel.

36 records · Page 2Linked to original sources
PubMed1988

Aplastic anemia complicating orthotopic liver transplantation for non-A, non-B hepatitis.

Aplastic anemia developed in 9 of 32 patients (28 percent) undergoing orthotopic liver transplantation for acute non-A, non-B hepatitis, at one to seven weeks after the procedure. No patient previously had evidence of hematologic dysfunction or conditions known to be associated with aplastic anemia. No other cases of aplastic anemia were identified among 1463 patients undergoing liver transplantation for all other indications at the four centers participating in the study (chi-square = 415, P less than 0.001; 95 percent confidence interval for the incidence of aplastic anemia after transplantation for non-A, non-B hepatitis, 13 to 44 percent, vs. 0.00 to 0.13 percent for all other indications). The operative and postoperative treatment of these patients was not otherwise different, indicating that the aplastic anemia was a complication of the hepatitis, not of the transplantation procedure. Four of the nine patients died of complications due to infections. Three of the surviving patients have been followed for less than six months, one for one year, and one for two years. The two patients followed the longest have recovered marrow function to an appreciable degree, and two of the others have evidence of early recovery. We conclude that patients undergoing orthotopic liver transplantation for non-A, non-B hepatitis are at a high risk for the development of aplastic anemia.

Adolescent↗
PubMed1988

Testicular Ca++ ATPase activity in mice: effects of age and gonadotropin administration.

These studies describe a high affinity calcium (Ca++)-dependent ATPase in purified testicular plasma membranes, which exhibits increased activity from weaning age to adulthood. Administration of human chorionic gonadotropin (hCG; 5 IU) increased enzyme activity in 21-day old and pubertal (35 to 40-day old), but not in adult mice. In pubertal mice, these increases in testicular Ca++-ATPase activity were dose-related and evident 60 min after hCG administration. A second challenge dose of 5 IU hCG administered either 24, 48 hrs, or 5 days later, had no additional effect on Ca++ ATPase in purified testicular plasma membranes in these pubertal animals. The present findings indicate that testicular plasma membrane Ca++ATPase activity exhibits a developmental pattern concomitant with increased testicular steroidogenic activity during sexual maturation. Furthermore, enzyme activity is increased by gonadotropic stimulation and exhibits a refractoriness similar to that of androgen biosynthesis to repeated hCG stimulation.

Aging↗
PubMed1988

Infections after liver transplantation. An analysis of 101 consecutive cases.

We studied infections in 101 consecutive patients who underwent liver transplantation between July 1984 and September 1985. The mean length of follow-up was 394 days. Eighty-three percent of population had 1 or more episodes of infection and 67% of the population had severe infections. The overall mortality was 26/101 (26%) and 23 of 26 deaths (88%) were associated with infection. Seventy percent of severe infections occurred in the first 2 months after transplantation. The most frequent severe infections were abdominal abscess, bacterial pneumonia, invasive candidiasis, Pneumocystis pneumonia, and symptomatic cytomegalovirus infection. Patients with more than 12 hours of cumulative surgical time had a higher rate of severe infections (P less than 0.001), particularly fungal (P less than 0.001) and bacterial (P less than 0.01) infections. Also, the use of choledocho-jejunostomy was associated with a higher rate of infection in patients who had more than 1 transplant operation (P less than 0.02). No increase in infection was found in patients who received azathioprine, or more than the median number of steroid boluses or "recycles"; but patients who received OKT3 therapy had a higher rate of protozoal infections (P less than 0.05). A result similar to that of our previous studies was a strong relation between the number of severe fungal infections and prolonged courses of antibiotics after transplant operation (P less than 0.001). Pretransplant manifestations of severe liver disease such as ascites, encephalopathy, and gastrointestinal bleeding were not associated with higher rates of infection after transplantation, but high serum levels of ALT were. Patients with lower ratios of T-helper to T-suppressor lymphocytes had more severe viral (P less than 0.02) and fungal (P less than 0.01) infections after transplantation.

Adult↗
PubMed1988

Antibody-mediated rejection of human orthotopic liver allografts. A study of liver transplantation across ABO blood group barriers.

A clinicopathologic analysis of liver transplantation across major ABO blood group barriers was carried out 1) to determine if antibody-mediated (humoral) rejection was a cause of graft failure and if humoral rejection can be identified, 2) to propose criteria for establishing the diagnosis, and 3) to describe the clinical and pathological features of humoral rejection. A total of 51 (24 primary) ABO-incompatible (ABO-I) liver grafts were transplanted into 49 recipients. There was a 46% graft failure rate during the first 30 days for primary ABO-I grafts compared with an 11% graft failure rate for primary ABO compatible (ABO-C), crossmatch negative, age, sex and priority-matched control patients (P less than 0.02). A similarly high early graft failure rate (60%) was seen for nonprimary ABO-I grafts during the first 30 days. Clinically, the patients experienced a relentless rise in serum transaminases, hepatic failure, and coagulopathy during the first weeks after transplant. Pathologic examination of ABO-I grafts that failed early demonstrated widespread areas of geographic hemorrhagic necrosis with diffuse intraorgan coagulation. Prominent arterial deposition of antibody and complement components was demonstrated by immunoflourescent staining. Elution studies confirmed the presence of tissue-bound, donor-specific isoagglutinins within the grafts. No such deposition was seen in control cases. These studies confirm that antibody mediated rejection of the liver occurs and allows for the development of criteria for establishing the diagnosis.

ABO Blood-Group System↗
PubMed1987

A simple staining method for chromatin in electron microscopy compatible with serial sectioning.

The study of the disposition of chromatin in the interphasic nucleus requires the combination of serial sectioning and a specific or preferential chromatin staining. The staining of chromatin with phosphotungstic acid (PTA) chromatin was originally employed on sections of glycolmethacrylate-embedded samples. As it is very difficult to obtain ribbons with this resin, we introduced a modification which consisted of staining the tissue after fixation and before dehydration, in order that epoxy resins can be applied. Several procedures were tried and the best results were attained in the following way. Standard fixation of samples no thicker than 1 mm was carried out with 2.5% glutaraldehyde at pH 7.2 for 1 or 2 h at room temperature; tissues were then rinsed three times with 0.2N HCl adjusted to pH 2.1-2.3 with 0.2N NaOH for 15 min. Staining was held with 3% W/V PTA in 1N HCl adjusted to the same pH. Samples were dehydrated in gradual ethyl alcohol concentrations and Epon-embedded. Post-staining on sections with uranyl-acetate and lead-citrate or other methods may be used to demonstrate other cell components and their relations to chromatin.

Animals↗
PubMed1987

Pediatric liver transplantation.

Liver transplantation, which once was an experimental procedure of no practical interest, has become the preferred treatment for infants and children dying of almost all non-neoplastic end-stage liver diseases. Liver replacement is being provided by many well-trained teams on all of the continents, as is evident from the program today--the first international symposium on pediatric liver transplantation. I have been honored in giving the first paper in the process of introducing the remarkable work of a gifted younger generation of physicians and surgeons.

Cyclosporins↗
PubMed1986

Cyclosporine trough concentration monitoring in liver transplant patients.

Trough blood or plasma concentration measurements of CsA must be carefully interpreted in OLT patients in relation to hepatic function, sample timing, assay specificity, and concurrent drug therapy. The RIA:HPLC ratio of blood or plasma measurements will vary with the patient's liver function, the time of blood sampling in reference to the time of drug administration, the absolute CsA concentration, and concurrent use of drugs that may alter the metabolism of CsA. The RIA assay should be used in conjunction with HPLC for trough blood or plasma measurement during the first postoperative weeks, during periods of changing hepatic function, and during changing drug regimens. In the future, the specific measurement of active or toxic metabolites of CsA should improve trough CsA concentration monitoring in OLT patients.

Chromatography, High Pressure Liquid↗
PubMed1985

Effect of platelet inhibition on experimental venous thrombosis in the rabbit.

An experimental model, based on a combination of endothelial damage and flow reduction, was used to induce thrombosis of the jugular vein in rabbits. The influence of ibuprofen, a cyclooxygenase inhibitor, was compared with that of dextran 70, which influences platelets, thrombus structure and flow. Albumin was used as a control of the volume-expanding effect of dextran. Ibuprofen was administered intravenously during the induction of thrombosis, and dextran and albumin were given 3 hours before the surgical procedure. Control rabbits received only Ringer's lactate. Dextran, but neither ibuprofen nor albumin, significantly reduced the incidence of thrombosis, though thrombus weight was not influenced. The data indicated that the effect of dextran in this model probably is primarily exerted via alteration of thrombus structure, and not by altered platelet function or hemodilution. The role of platelets in the initial development of thrombosis in this model thus may be questioned.

Albumins↗
PubMed1985

In vivo evaluation of the acute thrombogenicity of the modified human umbilical vein and autologous artery.

With the aim to evaluate acute thrombogenicity, segments of human umbilical vein grafts (Dardik Biograft, Meadox Medicals, Inc., Oakland, N.J.), nonheparinized, heparin-alcohol-treated, or covalently heparinized, were implanted into the carotid arteries of sheep. Autologous carotid arteries were used as control grafts. Flow was restricted to 25 ml/min. Accumulation of autologous 32P-labeled platelets was registered at both anastomotic and midgraft regions for 240 minutes. At the end of the perfusion period, grafts were removed, opened longitudinally, and the thrombus-free surface (TFS) and thrombus weight determined. The ex vivo determinations showed good correlation with results obtained with in vivo registration. In vivo accumulation of platelets was significantly larger in nonheparinized human umbilical vein grafts compared with heparin-alcohol treated grafts. Covalently heparinized grafts showed a tendency toward lower radioactive values, but visual examination after perfusion revealed areas of "intimal" damage with thrombotic deposits, probably caused by heparinization procedure. Autologous arteries showed the largest TFS and the smallest thrombi. Platelet accumulation in autologous arteries decreased almost to reference values after an initial rapid increase. In conclusion, heparin-alcohol treatment of human umbilical vein grafts reduces acute thrombogenicity. Although covalent heparin bonding seems to act in the same way, the fragility of the graft appears to preclude use of this method. Autologous arteries exhibit excellent antithrombotic characteristics.

Acute Disease↗
PubMed1984

Effects of dihydroergotamine on the feline cardiovascular response to intravenous infusion of live Escherichia coli bacteria.

A septic shock state was induced in cats by intravenous infusion of live Escherichia coli bacteria. Cats pretreated with an unspecific 5-HT blocker, dihydroergotamine (DHE), or with a specific 5-HT blocker, ketanserin, were compared with a series receiving bacteria without pretreatment. DHE pretreatment prevented the reduction in systemic arterial blood pressure found in the other series during the 2-hour period of septic shock. Pretreatment could not influence the increased vascular resistance in the pulmonary vascular bed or the early increase in pulmonary arterial blood pressure. Peripheral blood flow distribution was studied using radioactive labelled microspheres. Compared to bacteremia without pretreatment, the 5-HT blockers increased CNS blood flow and ketanserin also prevented the reduction in pancreatic blood flow. Gastric blood flow and gastric mucosal blood flow remained unchanged in all series as did the small intestinal total blood flow. Small intestinal mucosal blood flow, however, was reduced after 2 h of bacteremia. Microscopy revealed no gastric epithelial damage while the jejunal mucosa was characteristically damaged. There was no correlation between the changes in the small intestinal blood flow and the degree of mucosal damage, however, supporting the countercurrent theory for the pathogenesis of these lesions.

Animals↗
PubMed1984

Effect of heparin, low molecular weight (LMW) heparin, and a heparin analogue on experimental venous thrombosis in the rabbit.

An experimental model based on a combination of endothelial injury and flow reduction, was used to induce jugular vein thrombosis in the rabbit. The influence of conventional heparin, a low molecular weight fragment (LMW heparin; M.W. 4 000-5 000) and a heparin analogue (sodium pentosan polysulfate) was compared. The drugs were administered intravenously during the induction of thrombosis. The control animals received Ringer's lactate. All treatments significantly reduced the frequency of thrombosis. In addition, LMW heparin caused a significant reduction of thrombus weight. Moreover, it was shown that local treatment with conventional heparin and LMW heparin after endothelial damage both reduced the frequency of thrombosis.

Animals↗
PubMed1981

Testing and treatment of arterial graft thrombosis.

The in vivo technique of Sauvage et al for determining prosthetic arterial graft thrombogenicity was employed in the sheep carotid model using 4 mm commercial expanded polytetrafluoroethylene (Gore-Tex) grafts. Expanded polytetrafluoroethylene was found to be thrombogenic at 4 hours of low flow in this model. At 24 hours all of these grafts were totally occluded at low flow rates. Intravenous use of ibuprofen (Motrin), a thromboxane inhibitor, in this model markedly reduced occlusion and thrombogenicity at 4 and 24 hours. All grafts were patent at 24 hours when ibuprofen was used.

Animals↗
PubMedDate not supplied

Orthotopic liver transplantation for acute and subacute hepatic failure in adults.

The role of liver transplantation in 29 patients with fulminant and subacute hepatic failure due to a variety of different causes was examined by comparing the outcome and a variety of "hospitalization" variables. Transplanted patients (n = 13) were more likely to survive (p less than 0.05), were younger (p less than 0.05) and spent more time in the hospital (p less than 0.025) than did those who were not transplanted (n = 16). Despite spending a much longer time in the hospital, transplanted patients spent less time in the intensive care unit (p less than 0.05) in coma (p less than 0.01) and on a respirator (p less than 0.01) than did those not transplanted. Most importantly, the survival rate for transplanted patients was significantly improved (p less than 0.05) as compared to those not transplanted. We conclude that liver transplantation can be applied successfully to the difficult clinical problem of fulminant and subacute hepatic failure.

Acute Disease↗
PubMedDate not supplied

Pathologic analysis of liver transplantation for primary biliary cirrhosis.

A retrospective histopathologic review of all pathologic specimens from 394 adult liver transplant patients was undertaken with clinical correlation to determine if primary biliary cirrhosis has affected the posttransplant course compared to all other indications for liver transplantation and if recurrent primary biliary cirrhosis has occurred after liver transplantation. We also compared the histopathologic features seen in native livers with primary biliary cirrhosis to failed allografts with chronic rejection. One hundred six of the 394 adult patients transplanted during this time (1981 to July, 1986) fulfilled clinicopathologic criteria for a diagnosis of primary biliary cirrhosis. Neither the incidence nor any qualitative pathologic feature of histologically documented acute cellular rejection differentiated subjects transplanted for primary biliary cirrhosis vs. other diseases. No correlation between the titers of antimitochondrial antibody and the presence of posttransplant hepatic dysfunction based on liver enzyme profiles or the development of chronic rejection was seen in patients transplanted for primary biliary cirrhosis. Minor differences noted in the posttransplant course of primary biliary cirrhosis patients as compared to other conditions (higher incidence of chronic rejection as a cause of graft failure) was seen, but this did not significantly affect graft or patient survival. Recurrent primary biliary cirrhosis could not be diagnosed with certainty in any patient. A comparison of failed chronically rejected allografts vs. native hepatectomies obtained from patients with primary biliary cirrhosis revealed the presence of chronic obliterative vasculopathy, centrilobular cholestasis, and lack of granulomas, cirrhosis, cholangiolar proliferation, copper-associated protein deposition and Mallory's hyalin in specimens with chronic rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoantibodies↗