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Biomedical subjects

J A Pons

Publications and source records attributed to J A Pons.

At least 19 recordsLinked to original sources
PubMed2006

Doppler ultrasonographic and scintigraphic assessment of an auxiliary heterotopic liver transplantation with portal vein arterialization in pigs.

OBJECTIVE: Our aim was to evaluate liver graft integrity and function using scintigraphy and ultrasonography in a porcine model of auxiliary heterotopic liver transplantation with portal vein arterialization (AHLT-PVA). MATERIALS AND METHODS: Using Doppler ultrasonography we evaluated eight AHLT-PVA by parenchymal echogenicity, portal and arterial anatomy, and portal and biliary system flow. Two types of scintigraphy were performed: microaggregated human albumin colloid scintigraphy and diisopropyl iminodiacetic acid (DISIDA) scintigraphy, both labeled with 99mTc. RESULTS: The animals were distributed into two groups. The first group consisted of three animals with clinical suspicion of graft dysfunction, in which the ultrasonographic study revealed areas of parenchymal destructuring. In the scintigraphic study, heterogenous uptake was observed; there was no uptake in one animal. Necropsy of these three animals revealed areas of graft necrosis. The second group consisted of five animals with good clinical evolutions, in which the ultrasonographic study showed portal dilation, portal flow with arterial spiculations, and homogenous echogenicity of the hepatic parenchyma. The scintigraphic study revealed homogenous uptake by the graft and an elimination speed of the hepatobiliary agent similar to that of the native liver. CONCLUSIONS: An heterogenous echostructure of the graft provided a sign of poor prognosis indicating necrosis in the same way as heterogenous uptake or nonuptake of radioisotope upon scintigraphy. Scintigraphy is a good method to evaluate biliary function and bile elimination. In an AHLT-PVA, the main ultrasound findings derived from arterialization were dilation of the portal system and portal flow with arterial spiculations.

Animals↗
PubMed2006

Risk factors of acute renal failure after liver transplantation.

The objective of this study was to determine the risk factors of postoperative acute renal failure (ARF) in orthotopic liver transplantation (OLT). We reviewed 184 consecutive OLT. Postoperative ARF was defined as a persistent rise of 50% increase or more of the S-creatinine (S-Cr). The patients were classified as early postoperative ARF (E-ARF) (first week) and late postoperative ARF (L-ARF) (second to fourth week). Preoperative variables were age, sex, comorbidity, indication for OLT, Child-Pugh stage, united network for organ sharing status, analysis of the blood and urine, and donor's data. Intraoperative variables were systolic arterial pressure, mean arterial pressure, pulmonary capillary wedge pressure, cardiac index, and systemic vascular resistance index. Surgical technique, number of blood products transfused, need for adrenergic agonist drugs, and intraoperative complications were also important. Postoperative variables were duration of stay in the intensive care unit, time on mechanic ventilation, liver graft dysfunction, need for adrenergic agonist drugs, units of blood products infused, episodes of acute rejection, re-operations, and bacterial infections. Firstly we carried out a univariate statistical analysis, and secondly a logistic regression analysis. The risk factors for E-ARF were: pretransplant ARF (odds ratio (OR)=10.2, P=0.025), S-albumin (OR=0.3, P=0.001), duration of treatment with dopamine (OR=1.6, P=0.001), and grade II-IV dysfunction of the liver graft (OR=5.6, P=0.002). The risk factors for L-ARF were: re-operation (OR=3.1, P=0.013) and bacterial infection (OR=2.9, P=0.017). The development of E-ARF is influenced by preoperative factors such as ARF and hypoalbuminemia, as well as postoperative factors such as liver dysfunction and prolonged treatment with dopamine. The predicting factors of L-ARF differ from E-ARF and correspond to postoperative causes such as bacterial infection and surgical re-operation.

Acute Kidney Injury↗
PubMed2005

Attitude toward deceased organ donation and transplantation among the workers in the surgical services in a hospital with a transplant program.

INTRODUCTION: There are data that suggest that the percentage of hospital workers not in favor of donation is relatively high, even in services that are directly related to transplantation. The objective was to analyze attitudes toward decreased organ donation in the surgical services. MATERIALS AND METHODS: A random sample was stratified by the surgical service and the job category (n = 263) in a third-level hospital with a transplant program assessed attitudes toward the donation of ones own organs after death using a questionnaire including psychosocial factors as validated in our geographic surroundings. Student t test and the chi-square test were used for data analysis. RESULTS: Favorable attitudes toward donation were observed in 68% (n = 178) as opposed to 32% with an attitude that was undecided or against the act (n = 85). The psychosocial variables that showed significant relationships with this attitude were age (most in favor are younger; P = .021); nonmedical surgical staff (50% against donation; P = .0001); resident physicians (94% in favor; P = .001); discussion and prior consideration of donation (P = .016); knowledge of the concept of brain death (an important factor in nonhealth staff; P = .010); attitude toward manipulation of the deceased (P = .011) and concerns about mutilation (P = .026); partner's opinion toward organ donation (P = .0001); and existence of frequent medical errors (P = .003). No significant differences were found, depending on whether the services were involved in a specific transplant program (P = .853). CONCLUSIONS: Favorable attitudes toward donation among the hospital staff on surgical services, including those who perform transplants, did not reach more than 70% and was determined by multiple psychosocial factors. Donation promotion activities are necessary for these services, given the importance that this group's negative attitude could have on the attitude of the general population.

Adult↗
PubMed2005

Attitude toward living related donation of patients on the waiting list for a deceased donor solid organ transplant.

INTRODUCTION: Spain is the country with the highest rate of donation from deceased individuals. However, given the deficit in organs, living donation is being encouraged. Our objective was to analyze attitudes toward living donation among patients on the waiting list for a transplant. MATERIALS AND METHODS: Patients on the waiting list for a kidney or liver transplant (n = 96; 46 kidney and 50 liver) in the last year had their attitudes toward living donation evaluated through a psychosocial survey performed in a direct interview with an independent health professional from the transplant unit and analyzed by Student t test and the chi-square test. RESULTS: Ninety-one percent were in favor of donating their organs when they die, 6% had doubts, and the remaining 3% were against it. Twenty percent would accept living donation from a family member (32% in liver vs 7% in kidney; P < .05), despite 89% of them accepting that there would be a risk to the family member. Twenty percent reported that a family member had suggested donating, but the patient was opposed. Finally, only 6% considered living donation to be their first choice, 42% did not consider this option. Up to 96% would donate an organ to a family member if they were requested to do so. CONCLUSION: Patients on the waiting list are not favorable to living related donation for themselves, although members of their family have proposed it to them. However, the liver patient is more prepared to accept it, possibly because that patient has no other alternative as do kidney patients have dialysis. Even so, they are favorable toward donating a living organ if a family member were to request one. In general, living donation is not being proposed to these patients as a real option, partly because of their doctors.

Adult↗
PubMed2005

Prevention of hyperacute rejection in a model of orthotopic liver xenotransplantation from pig to baboon using polytransgenic pig livers (CD55, CD59, and H-transferase).

INTRODUCTION: The search for alternative sources for transplant organs leads us to the search for animals as an inexhaustible source of organs. The objective of this study was to analyze whether livers from polytransgenic pigs expressing the human complement regulatory proteins CD55 (hDAF), CD59, and alfa alpha1,2-fucosyltransferase (H-transferase), protected against hyperacute rejection after orthotopic liver xenotransplantation to a baboon and also to study pig liver function in a nonhuman primate. MATERIALS AND METHODS: Nine liver transplants from pig to baboon were divided into two groups: a control group (n = 4) of genetically unmodified pigs and an experimental group (n = 5) of pigs transgenic for CD55, CD59, and H-transferase as donors. All the donating piglets obtained through hysterectomy were maintained in specific pathogen-free conditions. The selection of transgenic pig donors followed demonstration of transgene expression using monoclonal antibodies (antiCD55, antiCD59) and immunohistological studies on liver biopsies. RESULTS: All animals in the control group developed hyperacute rejection with survival rates less than 16 hours without function of transplanted livers. In the experimental group none of the animals suffered hyperacute rejection. Survival in this group was between 13 and 24 hours. The livers were functional, producing bile and maintaining above 35% prothrombin activity. Only in one case was there primary dysfunction of the xenograft. CONCLUSION: Polytransgenic livers for complement regulatory proteins prevent hyperacute rejection when xenotransplanted into a baboon.

Acute Disease↗
PubMed2005

Attitudes toward living liver donation among hospital personnel in services not related to transplantation.

INTRODUCTION: The deficiency in livers and waiting list mortality have encouraged more living liver donation, although it is not exempt from morbidity and mortality. The enthusiasm of transplant teams for this kind of donation is increasing; however, the attitudes toward it are not so clear among other health professionals. Our objective was to analyze the attitudes toward living liver donation among hospital professionals in services without habitual relations with transplantation. MATERIALS AND METHODS: A random sample was stratified for service not related to transplantation and job category, in a third level hospital with a transplant program. Attitudes toward living liver donation were evaluated using a psychosocial questionnaire on living donation. RESULTS: A total of 419 respondents were analyzed (doctors, n = 184; nurses, n = 119; assistant nurses, n = 80; and non-health workers, n = 36), with a mean age of 37 +/- 10 years. The attitude toward living liver donation was favorable in 82% (n = 344). Among the other respondents, half (9%; n = 38) were against and the other half (9%; n = 37) were undecided. No significant differences were found among the doctors, nurses, assistants, and non-health workers. However, when the three categories were grouped in opposition to the non-health workers, there was greater indecision among non-health workers than the others (19% vs 8%; P = .0001). On analyzing the variables that determine this attitude we observed the following: having commented upon and previously discussed donation (P = .016); believing in the possibility of needing an organ oneself (P = .0001); and being in favor of living kidney donation (P = .0001) and cadaveric donation (P = .004). CONCLUSIONS: Hospital personnel in services not related to transplantation favor living liver donation, especially if it is a related donation, despite its greater risk, except among non-health workers. However, it is important to conduct informative and awareness-raising campaigns in hospitals if such a type of transplantation is to be encouraged.

Adult↗
PubMed2005

Pathology findings in a model of auxiliary liver transplantation with portal vein arterialization in pigs.

OBJECTIVE: To determine the histological findings and temporal evolution that occur in auxiliary liver grafts as a consequence of arterialization of the portal vein (PVA). MATERIALS AND METHODS: We evaluated 10 auxiliary heterotopic liver transplants with arterialization of the PVA. The histological study was performed using an optical microscope to process liver samples with staining using hematoxylin and eosin. A biopsy of native liver tissue was used as a control. RESULTS: Two animals were excluded from the study, one due to ischemic necrosis of the graft and one that died 4 hours after transplant. All of the remaining eight animals underwent a histological study at 1 day, 7 days, and 14 days. The most significant histological findings were: (1) dilation of portal areas and sinusoids, which were detected at 24 hours and persisted; (2) thickening of the interlobular septum, which was observed after day 7 and progressively increased to day 14; (3) bile duct hyperplasia detected at the seventh day. CONCLUSIONS: The consistent, early findings in a pig liver with PVA included vascular dilation of the portal area and the sinusoids, with bile duct hyperplasia extending progressively and the thickening of interlobular connective tissue septa with a generalized perilobular connective tissue reaction, which did not seem to alter the internal structure of the lobule, which showed histologically normal hepatocytes. The fibrous reaction may be the first stage in chronic hepatopathy. Further long-term studies are required in this model.

Animals↗
PubMed2003

Does the standard vs piggyback surgical technique affect the development of early acute renal failure after orthotopic liver transplantation?

The objective of this study was to evaluate the effect of the surgical technique on postoperative renal function during the first week after liver transplantation (OLT). We performed a retrospective study of 184 consecutive OLT. Criteria for acute renal failure were: serum creatinine >1.5 mg/dL, an increase by 50% in the baseline serum creatinine, or oliguria requiring renal replacement therapy. The distribution of patients according to the surgical technique was: standard (n=84), venovenous bypass (n=20), and piggyback (n=80). Other variables analyzed were: intraoperative requirement for blood products, treatment with adrenergic agonists, intraoperative complications, and postreperfusion syndrome. Univariate analysis showed the following parameters to be significantly related to postoperative renal failure: intraoperative fresh frozen plasma and cryoprecipitate requirements, intraoperative complications, postreperfusion syndrome, need for noradrenaline or dobutamine, standard surgical technique versus piggyback (39% vs 18%, P<.01) and venovenous vs piggyback (50% vs 18%, P<.01). Logistic regression analysis identified the following variables as having independent prognostic value: (1) Standard surgical technique vs piggyback (OR=3.3, P=.01); (2) venovenous vs piggyback (OR=4.7, P=.02); and (3) >20 U cryoprecipitate requirement (OR=1.04, P=.01). In conclusion, compared with the piggyback technique, the standard surgical technique appears to be an independent risk factor for postoperative acute renal failure. When venovenous bypass is used in patients who do not tolerate trial clamping of inferior vena cava, it does not reduce the incidence of postoperative renal failure. Finally, the piggyback technique significantly reduces the probability of acute renal failure after liver transplantation.

Acute Kidney Injury↗
PubMed2003

Immunopathology of an hDAF transgenic pig model liver xenotransplant into a primate.

BACKGROUND: hDAF transgenic pigs do not display the inherent hyperacute rejection reactions of pig-to-primate xenotransplants. The purpose of this study was to determine the immunopathologic phenomena following an hDAF transgenic pig hepatic orthotopic xenotransplant into a baboon. METHODS: Donor animals were unmodified pigs (n=4) and hDAF transgenic pigs (n=2). Recipient animals were baboons (Papio anubis). Liver biopsies were immunostained using monoclonal antibodies to C3, C5b-9, IgG, IgM, CD2, CD4, CD8, CD68, CD20, Bric 216, CD31, and fibrin, and polyclonal antibody to C4. RESULTS: hDAF transgenic grafts showed IgG, IgM, and C4 endothelial deposits. However, no fibrin, C3, or C5b9 deposits were observed after reperfusion. hDAF xenografts displayed CD31 staining in the portal spaces, perilobular areas, and at hepatic sinuisoidal levels. The baboon that lived for 4 days displayed either CD4 or CD8 T-cells periportal infiltrate. CONCLUSIONS: Future studies will seek to determine the physiologic role of CD31 hepatic sinusoidal expression in transgenic xenotransplants, and will also study the role of T-cell infiltrates in xenograft rejection.

Animals↗
PubMed2003

Description of a new auxiliary heterotopic partial liver transplantation technique with portal vein arteriolization of applicability in heterotopic liver xenotransplantation.

OBJECTIVE: The aim of this study was to describe a new model of auxiliary heterotopic partial liver transplantation with portal vein arterialization. MATERIALS AND METHODS: Three standard hepatectomies were performed in pigs. The left lateral lobe was surgically resected and portal vein arteriolization constructed by an end-to-side "Y" anastomoses between the distal to the celiac axis aorta and the portal vein. RESULTS: The graft was placed in the left iliaca fossa using anastomoses of the donor infrahepatic inferior cava vein end-to-side to the host infrarenal inferior vein and the donor aortic stump with portal vein arteriolization end-to-side to the left iliac artery. After graft reperfusion, the 3 recipients showed intraoperative hypotension, which was treated with fluid administration and vasoactive drugs. At the end of the operation, the graft displayed normal arterial blood flow and good venous drainage. The donor liver graft appeared more red than the host liver, which was due to the increased arterial blood flow. One pig of 3 died at 24 hours after surgery, probably due to hypothermia. However, the other 2 pigs survived the procedure and remained stable. Echographic monitoring showed intrahepatic arterial expansion, which may be the result of high blood pressure due to the arteriolization procedure. CONCLUSIONS: We have developed a novel and easy to perform technique that diminishes the number of anastomoses and does not involve vessels from other organs.

Anastomosis, Surgical↗
PubMed2003

Can we expand the indications for liver transplantation among hepatocellular carcinoma patients with increased tumor size?

INTRODUCTION: Due to the scarcity of donors and the fact that size is the main prognostic factor, Milan criteria have been used since 1996 to select hepatocellular carcinoma (HCC) patients for liver transplantation. In 2001 UCSF criteria showed that including layer tumors did not reduce the survival results. The objective of this paper was to evaluate whether HCC tumor sizes exceeding the Milan criteria adversely influence survival rates. PATIENTS AND METHODS: Between May 1988 and July 2001, 53 patients were transplanted due to HCC and cirrhosis. The etiology of cirrhosis was HCV in 23 cases and HBV in 6. In 11 cases the HCC were incidental by discovered namely, a mean/ diameter of 1.8 cm (versus 2.6 cm in nonincidental HCC). Sixty-two percent of tumors met the Milan criteria, and 68% the USCF criteria. RESULTS: The actuarial survival was 79% at 1 year and 62% at 5 years. The survival of patients with incidental HCC was 82% at 1 year and 82% at 5 years, which is better than the survival of those with nonincidental HCC (78% at 1 year and 57% at 5 years, P<.05). According to Milan criteria, the survival patients with early tumors was 82% at 1 year and 68% at 5 years, and for advanced tumors (NS), 75% and 54%, respectively. Comparison of early versus advanced tumors according to UCSF criteria showed survivals of 84% versus 64% at 1 year (P<.05) and 67% versus 48% at 5 years (P<.05), respectively. CONCLUSION: Increasing the HCC size among LT according to the California criteria did not reduce survival rates compared with the Milan criteria.

Alcoholism↗
PubMed2003

Primary eosinophilic esophagitis.

Eosinophilic esophagitis is an uncommon pathology that generally affects children with a history of allergies and intrinsic asthma. We present a clinical case of eosinophilic esophagitis in a 16-year-old boy with upper dysphagia for solids since childhood. The analytical study showed only a repeat serum eosinophilia. Barium transit disclosed a reduction in caliber of the whole esophagus. Functional esophageal tests with pH monitoring and manometry were normal. Endoscopy showed a small-diameter esophagus and fibrosis with a very friable mucosa. The histological study of the esophageal biopsies revealed a full thickness major eosinophil infiltration of the esophagus. These findings suggest a differential diagnosis with a great variety of pathologies that can cause similar lesions in the esophagus, especially between primary eosinophilic esophagitis and eosinophilic esophagitis secondary to gastro-esophageal reflux disease (GERD). We implemented medical treatment with oral corticoids and total suppression of allergens from the diet, and the patient was asymptomatic.

Adolescent↗
PubMed2002

Copper metabolism and biliary secretion in patients receiving orthotopic liver transplantation.

BACKGROUND: The quantitative aspects of biliary copper excretion in health and disease have not been fully defined yet. The aim of the study was to evaluate copper metabolism and biliary excretion of patients who have received an orthotopic liver transplant (OLT) during the immediate postoperative period. METHODS: We have studied retrospectively 16 patients undergoing primary OLT and eight undergoing cholecystectomy, and measured serum concentration of copper and its secretion in bile and urine by flame atomic absorption spectrometry (FAAS). RESULTS: We found a progressive increase of biliary copper secretion rates and a corresponding lowering of urinary copper during the postoperative period. Thus, in OLT patients, the mean of biliary copper secretion on day 1 is 0.7+/-0.2 micromol/day compared with 2.3+/-1.1 micromol/day on day 7 (p<0.01) and 6.1+/-2.5 micromol/day on day 15 (p<0.0001). The rate of copper output on day 5 after surgery is about one sixth of the value reported for patients who had undergone cholecystectomy. In patients suffering an acute rejection episode, there was an abrupt fall in bile flow (<15 ml/day) and excretion of biliary copper (<1 micromol/day), accompanied by an increase of urine copper excretion (>3 micromol/day), and both were recovered when the rejection episode was solved. We found an inverse relationship between the serum bilirubin (Bt), alkaline phosphatase (ALP) and the biliary copper excretion (p<0.01), and a direct relationship with urinary copper excretion (p<0.01). CONCLUSIONS: The copper measurements in urine and bile are non-invasive techniques, of low cost, rapid and easy to accomplish, and available in hospitals accredited for hepatic transplantation. These characteristics make these methods helpful in the monitoring of patients submitted to OLT for assessment of graft quality and subsequent outcome.

Adult↗