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J A Pons

Publications and source records attributed to J A Pons.

At least 37 records · Page 2Linked to original sources
PubMed2001

Evolution of proto-neutron stars with quarks.

Neutrino fluxes from proto-neutron stars with and without quarks are studied. Observable differences become apparent after 10-20 s of evolution. Sufficiently massive stars containing negatively charged, strongly interacting, particles collapse to black holes during the first minute of evolution. Since the neutrino flux vanishes when a black hole forms, this is the most obvious signal that quarks (or other types of strange matter) have appeared. The metastability time scales for stars with quarks are intermediate between those containing hyperons and kaon condensates.

Journal Article↗
PubMed1998

Effect of partial HLA class I match on acute rejection in viral pre-infected human liver allograft recipients.

BACKGROUND: Acute rejection in liver transplants is one of the commonest causes of liver dysfunction in the early postoperative period. However, the factors involved in liver graft rejection are still unknown. Our study was aimed at ascertaining whether the degree of HLA class I and class II compatibility or pretransplant viral infection have any influence on early acute liver graft rejection. METHODS: We reviewed clinical and laboratory data in 190 consecutive patients who underwent a liver transplant. HLA-A, HLA-B, and HLA-DR typing for the establishment of an HLA match score was performed by a standard microcytotoxicity method. The existence of pretransplant viral infection was investigated in sera and biopsy tissue by serologic (hepatitis B virus, hepatitis C virus) and polymerase chain reaction (cytomegalovirus) techniques, respectively. The influence of these two factors in acute rejection and the interaction between them was also analyzed. RESULTS: A strong association between viral infection and acute rejection in the group with partial class I matching was found (odds ratio=7.75; P<0.0009), whereas no correlation was observed in the group with zero class I matching (odds ratio=0.98; P=0.81). The rejection percentage in the group in which partial class I match and viral infections coexisted was 60%, whereas in the partially class I-matched group without pretransplant viral presence it was 16%. CONCLUSIONS: These findings suggest a participation of partial HLA class I compatibility in triggering acute rejection in recipients suffering preoperative viral infections and support the idea that HLA class I antigen matching could play a role as a linking element between the MHC-restricted T cell-mediated response to viral infection and the allogenic response in liver transplantation.

Adolescent↗
PubMed1998

Liver transplantation in hepatitis C. A Spanish multi-centre experience.

OBJECTIVE: The purpose of this retrospective survey was to determine the prevalence and outcome of hepatitis C virus (HCV) infection in cirrhotic patients undergoing liver transplantation (OLT) in Spain in 1992. METHODS: Post-OLT HCV infection was defined by anti-HCV (second-generation ELISA) and/or PCR. Patients were divided into groups A (HCV-positive pre-OLT: n = 124, 46%) and B (HCV-negative pre-OLT: n = 145, 54%). RESULTS: HCV infection was more prevalent in patients originally diagnosed as having non-A non-B cirrhosis (97%) and cryptogenic cirrhosis (79%) than in patients with cholestatic or metabolic diseases. Group A patients were older (53.3+/-7.9 versus 47.6+/-9.7; P< 0.05) and had a higher prevalence of hepatocellular carcinoma (22% versus 4%, P< 0.05). Post-OLT HCV infection was 99% in group A versus 4% in group B (P< 0.05). Histological hepatitis developed in 39% (66% in group A versus 14% in group B, P< 0.05) with similar follow-up. Chronic rejection occurred in 6% (3% in group A versus 8.5% in group B, P= 0.07). Retransplantation rate (overall 8%) and two-year patient survival did not differ between groups (79% versus 72%). Graft survival was higher in group A (74% versus 65% at 2 years, P= 0.04). CONCLUSIONS: HCV-cirrhosis represented the most frequent indication for OLT in Spain in 1992. While HCV recurrence was universal, de novo acquisition was rare. HCV accounted for most post-OLT hepatitis (87%), but was not associated with chronic rejection, nor with a higher retransplantation rate. Patient survival was not different in HCV patients compared to a control group after a follow-up of 2-3 years. Therefore, at present, HCV-cirrhosis is an acceptable indication for OLT.

Adolescent↗
PubMed1995

Clinical improvement after liver transplantation for type I familial amyloid polyneuropathy.

Long-term results of 13 liver transplantations in patients with a previous diagnosis of type I familial amyloid polyneuropathy (FAP) are presented. The diagnosis of type I FAP was based on the presence of a biochemical marker in the plasma (TTR-Met-30 in 11 patients, TTR-Ala-71 in two). Maximum follow-up is 28 months and the survival rate stands at 11 of 13 patients. Two patients died from sepsis at 2 and 6 months. TTR disappeared from plasma in all cases. Neurological status improved in all eight patients undergoing transplantation more than 6 months previously, although electromyographic studies showed a slight improvement only in the six with follow-up of more than 1 year. All 13 patients showed a hyperdynamic haemodynamic pattern with a high incidence (four patients) of the use of venovenous bypass due to haemodynamic intolerance. Two patients also received transplants by the 'piggy-back' technique. In conclusion, liver transplantation may be useful in the treatment of certain patients with FAP to halt and improve the neurological consequences of the disease.

Adult↗
PubMed1995

Role of liver transplantation in viral hepatitis.

Liver transplantation remains difficult in end-stage liver disease caused by chronic viral hepatitis because of recurrent viral infection in the liver graft. After transplantation for chronic hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis delta virus (HDV) disease, recurrence is nearly universal. Patients with actively replicating HBV infection before transplantation appear to be the most likely to experience clinically significant recurrent hepatitis, whereas recurrence in liver transplant patients with HCV and HDV infection before transplantation seems to be less serious in the transplanted liver. At present, hepatitis B Ig immunoprophylaxis can be given to reduce the rate of HBV recurrence in liver graft. However, further studies are needed on ways to prevent and treat viral recurrence in liver transplant patients with viral hepatitis.

Hepatitis A↗
PubMed1994

Analysis of hepatitis B precore region in serum and liver of chronic hepatitis B virus carriers.

Using an oligonucleotide hybridization assay we studied the prevalence of wild-type and the predominant pre-core mutant hepatitis B virus in serum and liver of 49 antibody to hepatitis B e antigen carriers and three hepatitis B e antigen positive patients. Of the 45 serum samples from the anti-HBe carriers analyzed (no serum sample was available in four patients), 36 (80%) had hepatitis B virus DNA. In 26 of these 36 patients (72%) a mixed population was detected, wild-type genome alone was found in six patients (16%), the single mutant (nucleotide position 1896), in three cases (8%) and in one patient (2%) the viral DNA had the two nucleotide mutation (1896 and 1899). Of the liver biopsies from the 36 anti-HBe patients studied (no liver biopsy was available in 13 patients), 33 (92%) had hepatitis B virus DNA. A mixed viral population was detected in 23 patients (69%), only wild-type virus or a single mutation was found in eight (34%) and two patients (8%), respectively. In all cases, wild-type was the predominant genome. In serum and liver samples from the same patient, we found a concordance of the presence of wild-type HBV and the pre-core mutants studied in 23/26 (88%) of the patients. Alanine aminotransferase levels were higher (p < 0.01) and the duration of hepatitis B surface antigen carrier lower (p < 0.02) in patients with a predominance of precore mutant in comparison to wild-type.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Hepatitis C in liver transplant patients.

The aim of this study was to determine whether infection by the hepatitis C virus (HCV) recurs after orthotopic liver transplantation (OLT) and to define the natural history of post-transplantation chronic hepatitis due to HCV. Of 70 patients, 10 (14.3%) were found to have antibodies to HCV before transplantation. After OLT 14 of the 70 patients (20%) had positive anti-HCV antibodies: 8 of 10 positive pre-OLT (80%) and 6 of 60 negative pre-OLT (10%). Of 14 patients anti-HCV+ post-OLT (57%), developed 8 chronic hepatitis: chronic persistent hepatitis in three patients, chronic lobular hepatitis in three patients and chronic, active hepatitis in two patients. We treated four patients with interferon obtaining normalization of transaminases in three of them after 6 months, but with a severe relapse in two. These results suggest that hepatitis C recurs in a majority, of liver transplant recipients and that morbidity is an important consideration. Interferon treatment of these patients requires further study to obtain conclusive results.

Adolescent↗
PubMed1994

Life quality of patients undergoing liver transplantation.

The aim of this study was to assess the life quality of a group of patients who had undergone liver transplantation using (1) a psychological test to evaluate family relations, work activity, emotional state and social relationships; (2) the quantification of hospital dependence and degree of fitness for work. Included in the study were 32 patients using the following criteria: diagnosis of hepatic cirrhosis and minimum posttransplant follow-up of 6 months. The average age of the study population was 44.8 +/- 10.5 years; there were 23 males and 9 females, with an average follow-up of 15 months. The psychological test used was the Quality of Life Scale (QLS) which consists of 21 items each scoring from 1 to 6 points. The questionnaire was completed before transplantation by all the patients, and after transplantation by 32 patients at 6 months, 20 at 12 months and 12 at 24 months. Hospital dependence was evaluated by the number of admissions and number of days per admission. Lastly, we compared fitness for work before transplantation and at 1 and 2 years after transplantation. The QLS test showed a post-transplant improvement in the four aspects assessed, particularly in the personal aspects (emotions and family) (P < 0.001). Hospital dependence following liver transplantation decreased significantly compared with the pretransplant situation (P < 0.01). Finally, the post-transplant percentage of unfitness for work decreased with time, reaching a significant differences 2 years after transplantation (P < 0.05).

Adult↗
PubMed1994

[Quality of life of cirrhotic patients before and after liver transplantation].

In this study we assessed the quality of life of a group of cirrhotic patients who underwent liver transplant using a psychological test to evaluate family relations, work activity, emotional state and social relations. The quantification of hospital dependence and degree of fitness for work, before and after the transplant were also analyzed. 32 patients were included in the study with the diagnosis of hepatic cirrhosis and minimum post-transplant follow-up of 6 months. The average age of the study population was 44.8 +/- 10.5 years; there were 23 males and 9 females, with an average follow-up of 15 months. The psychological test used was the Quality of Life Scale (QLS), which consists of 21 items, each scoring from 1 to 6 points. The questionnaire was completed before the transplant by all the patients, and after the transplant by 32 patients at 6 months, 20 at 12 months and 12 at 24 months. Hospital dependence was evaluated by number of admissions and number of days per admission. Lastly, we compare the rate of unfitness for work before the transplant and at one and two years after the transplant. The QLS test showed a post-transplant improvement in the 4 aspects assessed, specially in the personal aspects (emotions and family) (p < 0.001). Hospital dependence following pre-transplant situation (p < 0.01). Finally, the post-transplant percentage of unfitness for work decreased with time, reaching significant differences 2 years after the liver transplant (p < 0.05).

Adult↗
PubMed1994

Hepatic artery complications after liver transplantation.

We present the arterial complications arising from 100 orthotopic liver transplants (OLT) carried out in 87 consecutive patients. Mean patient age was 42.5 +/- 12.8 years (7-63). There was a predominance of male patients (67%). The most common indications were hepatic cirrhosis (53%) and severe acute hepatitis insufficiency (14%). The donor liver presented 29 arterial malformations, mainly a left hepatic artery arising from the left gastric artery, either as a single or associated anomaly. Only six arterial complications appeared in 4 of the 87 patients. Of these six, four corresponded to arterial thrombosis, and the remaining two to arterial stenosis and a ruptured mycotic aortic aneurysm. Two of the 4 patients had a double arterial complication (one had arterial thrombosis in 2 of the 3 grafts, and the other presented arterial thrombosis and aortic rupture). No arterial complications were related to arterial anomalies in the donor liver. Three of the 4 patients died from the complication. The 1-year actuarial survival rate in our series is 77.5%. In conclusion, arterial complications are infrequent in our series (6%) but do carry a high mortality rate (75%).

Adult↗
PubMed1993

[Liver transplantation for the treatment of type I familial amyloidotic polyneuropathy].

The first liver transplantation carried out in Spain for the treatment of type I familial amyloidotic polyneuropathy (FAP I) is presented. The reason for the operation was based on the liver being responsible for the synthesis of abnormal transtirretin (TTR) constituting the peculiar amyloid of the disease. Following transplantation a rapid and noticeable decrease in abnormal TTR was observed and the evolution of the clinical picture after 18 months of surgery is favorable with progressive improvement of the neurologic symptoms and normal function of the graft. These encouraging results coincide with those of the Swedish group of Umea, the pioneer of this procedure.

Adult↗
PubMed1993

Reoperation for biliary tract complications following orthotopic liver transplantation.

Biliary tract complications were analysed after 54 orthotopic liver transplantations performed in 49 patients over a 2-year period. Reconstruction of the bile duct consisted of end-to-end choledochocholedochostomy over a T tube in 47 cases and Roux-en-Y choledochojejunostomy in seven (two for sclerosing cholangitis, one for secondary biliary cirrhosis, four retransplants). The T tube was withdrawn 12-16 weeks after operation in all but two patients (2-3 weeks). There was no intraoperative mortality. Eight patients (16 per cent) died during the first month and the 1-year actuarial survival rate was 75 per cent. Early biliary complications (up to 3 months after operation) consisted of five bilomas, for which ultrasonographically guided drainage was effective in three and surgical drainage necessary in two. Late biliary complications (3 months onwards) consisted of biliary peritonitis following T tube removal (four patients; reoperation was required in all four) and necrosis of the bile duct secondary to a late arterial thrombosis (one). The incidence of reoperation as a result of early biliary complications was low (two patients), but higher for biliary peritonitis following T tube removal.

Adolescent↗
PubMed1993

Fulminant hepatic failure after Lepiota mushroom poisoning.

We present ten patients who suffered from a cyclopeptide syndrome from two different foci, one caused by Lepiota helveola (seven cases) and the other by Lepiota brunneoincarnata (three cases). Of the ten victims, five recovered completely after the intestinal stage and the other five developed a phase of visceral involvement with alterations of liver function. In two patients, hepatic function became normal after the 7th day after ingestion. Three patients developed fulminant hepatitis and two of these died of adult respiratory distress syndrome. The fulminant hepatitis patient who later improved developed active chronic hepatitis 1 year later. Finally, five patients developed mixed polyneuropathy. In this paper the indications for orthotopic liver transplant (OLTx) are discussed and the development of late complications such as active chronic hepatitis and mixed polyneuropathy are considered.

Adult↗