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Elwyn Elias

Publications and source records attributed to Elwyn Elias.

13 recordsLinked to original sources
PubMed2006

Oxidative stress induces actin-cytoskeletal and tight-junctional alterations in hepatocytes by a Ca2+ -dependent, PKC-mediated mechanism: protective effect of PKA.

Oxidative stress elevates Ca2+ and, presumably, activates Ca2+ -dependent PKCs. We analyzed the participation of Ca2+ -dependent PKCs in actin disorganization and tight-junctional impairment induced by the pro-oxidant tert-butylhydroperoxide (tBOOH) in isolated rat hepatocyte couplets. tBOOH (100 microM) augmented radical oxygen species (ROS), as indicated by increased lipid peroxidation (+217%, p < 0.05) and intracellular production of 2',7'-dichlorofluorescein (+36%, p < 0.05). Cytosolic Ca2+ and PKCalpha translocation to membrane, an indicator of PKCalpha activation, were also elevated by tBOOH (+100 and +79%, respectively, p < 0.05). tBOOH increased the number of couplets displaying membrane blebs (+278%, p < 0.001) and caused redistribution of F-actin. tBOOH induced tight-junctional impairment, as indicated by a reduction in the percentage of couplets retaining presecreted cholyllysylfluorescein in their canalicular vacuoles (-54%, p < 0.001). tBOOH induced redistribution of the tight-junctional-associated protein ZO-1. All these events were prevented by the panspecific PKC inhibitors H7 and staurosporine, the Ca2+ -dependent PKC inhibitor Gö6976, the intracellular Ca2+ chelator BAPTA/AM, and the PKA activator dibutyryl-cyclic AMP. Furthermore, PKC inhibition and PKA activation not only prevented but also fully reversed tBOOH-induced blebbing. Conversely, tBOOH-induced ROS formation and Ca2+ elevation remained unchanged. We conclude that ROS induce hepatocellular actin-cytoskeleton rearrangement and tight-junctional impairment by a PKC-mediated, Ca2+ -dependent mechanism, which is counteracted by PKA.

Actins↗
PubMed2006

Oxidative stress induces internalization of the bile salt export pump, Bsep, and bile salt secretory failure in isolated rat hepatocyte couplets: a role for protein kinase C and prevention by protein kinase A.

We have shown that Ca2+-mediated protein kinase C (PKC) activation induces impairment of bile salt secretory function and F-actin redistribution in hepatocyte couplets. Because oxidative stress induces Ca2+ elevation, we tested here whether PKC inhibition or protein kinase A (PKA) activation, which often counteracts PKC-dependent effects, can prevent and reverse these alterations. The pro-oxidant compounds tert-butylhydroperoxide (tBOOH, 100 microM) and 2,3-dimethoxy-1,4-naphthoquinone (30 microM), reduced by -41% and -29%, respectively, the percentage of couplets accumulating the fluorescent bile salt analog, cholyl-lysylfluorescein in their canalicular vacuoles (p < 0.01). tBOOH-induced bile salt secretory failure was accompanied by internalization of the canalicular bile salt export pump (Bsep), and disarrangement of cytoskeletal F-actin. All these deleterious effects were fully prevented by the intracellular Ca2+ chelator BAPTA/AM (20 microM), the pan-specific PKC inhibitors H7 (100 microM) and staurosporine (1 microM), the inhibitor of Ca2+-dependent PKCs, Gö6976 (2 microM), and the PKA activator dibutyryl-cAMP (500 microM). H7, Gö6976, and dibutyryl-cAMP not only prevented but also fully reversed the decrease in the cholyl-lysyl-fluorescein accumulation. In conclusion, these results suggest that low levels of oxidative stress impair bile salt secretion by internalizing Bsep through a Ca2+-dependent, PKC-mediated mechanism, and that inhibition of PKC, or activation of PKA, prevents and reverses these effects. Alterations in actin organization may be a causal factor.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

Liver transplantation as a cure for acute intermittent porphyria.

Acute intermittent porphyria occasionally causes frequent and crippling acute neurovisceral attacks associated with increased hepatic production of porphyrin precursors, resulting in long-term damage, poor quality of life, and shortened life expectancy. There has been no cure for this condition, but replacement of deficient hepatic enzymes might restore excretion of porphyrin precursors to normal and prevent acute attacks. We aimed to treat severe acute intermittent porphyria in a 19-year-old woman by liver transplantation. After the transplant, concentrations of haem precursors in the patient's urine returned to normal, and 1.5 years later her quality of life was good. Our report suggests some hope of cure for selected patients with severe forms of this disease.

Adult↗
PubMed2004

PTFE-covered stents improve TIPS patency in Budd-Chiari syndrome.

Transjugular intrahepatic portosystemic shunt (TIPS) have been shown to be an efficient portal-systemic derivative treatment for Budd-Chiari syndrome (BCS) patients uncontrolled by medical therapy. However, the main drawback of TIPS for this condition is a very high rate of shunt dysfunction. Recently, polytetrafluoroethylene (PTFE)-covered stents have been shown to reduce the incidence of TIPS dysfunction in patients with cirrhosis. The aim of the study was to assess the incidence of TIPS dysfunction in 2 cohorts of BCS patients treated with bare or PTFE-covered stents. The study included 25 TIPS procedures (16 bare stents and 9 covered stents) with a median follow-up period of 20.4 months (range, 3.9-124.8). Fourteen of 16 patients (87%) receiving bare stents had TIPS dysfunction compared to 3 of the 9 patients (33%) receiving PTFE-covered stents (P = .005). The actuarial rates of primary patency in the bare-stent group were 19% at 1 year compared with 67% in the PTFE-covered stent group (P = .02; log-rank test). The number of additional interventional procedures to maintain TIPS patency was significantly greater in the bare-stent than in the PTFE-covered stent group (1.9 +/- 1.2 vs. 0.6 +/- 0.9; P = .007). The number of patients with clinical relapses was greater in the bare-stent group compared to the PTFE-covered stent group (13 vs. 5 episodes in 9 and 3 patients, respectively). In conclusion, PTFE-covered stents have a considerable advantage over bare stents for the TIPS treatment of BCS patients, with a lower dysfunction rate, a lower number of reinterventions, and fewer prosthesis requirements. PTFE-covered stents are preferable in patients with Budd-Chiari Syndrome.

Actuarial Analysis↗
PubMed2003

Obstetric cholestasis with elevated gamma glutamyl transpeptidase: incidence, presentation and treatment.

BACKGROUND: Obstetric cholestasis (OC) may cause severe pruritus in the mother and lead to fetal distress and stillbirth. The etiology of OC is multifactorial, but includes inherited dysfunction of bile canalicular transporters. One of these, multidrug resistant protein 3 (MDR3), a phospholipid transporter, when dysfunctional is associated with elevated levels of gamma glutamyl transpeptidase (GGT). The aim of the present study was to assess the incidence of OC associated with elevated GGT. We compared the natural history of a cholestatic pregnancy and the efficacy of ursodeoxycholic acid (URSO) in OC patients grouped according to a normal or raised GGT level. METHODS: Eighty-one patients with OC were analyzed. OC was diagnosed in patients with pruritus and elevated serum bile acids (SBA). Fifty-seven consenting volunteer patients (70%) were treated with URSO. RESULTS: Elevated GGT at presentation was found in 21 patients (30%) and was associated with significantly higher serum levels of aspartate transaminase (AST), bilirubin (BIL) and SBA. OC presented at approximately the same gestation week in both groups of patients. In patients not treated with URSO, liver function tests (LFT) showed no significant change from the time of diagnosis to delivery. Patients from both groups responded to URSO with significant improvement in their AST and alanine aminotransferase (ALT) levels, but SBA fell significantly only in the normal GGT group. CONCLUSIONS: An elevated GGT occurs in less than one-third of patients with OC in the UK and, when present, is associated with greater impairment of LFT, but no difference in gestational age at onset. Treatment with URSO appears to be safe and significantly improves LFT in patients with OC, with the exception of SBA in the high GGT group.

Alanine Transaminase↗
PubMed2002

Obstetric cholestasis.

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ATP Binding Cassette Transporter, Subfamily B↗
PubMed2002

Complexities in ETS-domain transcription factor function and regulation: lessons from the TCF (ternary complex factor) subfamily. The Colworth Medal Lecture.

The ETS-domain transcription factor family can be divided into a series of subfamilies. Elk-1 represents the founding member of the ternary complex factor (TCF) subfamily. By focusing on the TCF subfamily, we can demonstrate the complexities that exist in the function and regulation of ETS-domain transcription factors. This article focuses on Elk-1 in detail and summarizes the functions of other TCFs. The key themes covered include the domain structure of the TCFs, the mechanisms of complex formation with serum response factor, regulation of TCFs by mitogen-activated protein kinase cascades, and transcriptional regulatory properties of the TCFs. Finally, the emerging role of the TCFs in vivo is discussed. A picture is developing indicating that, while these proteins exhibit significant sequence and functional conservation, key differences in their structure and regulation are being identified which may relate to unique functions of these proteins in vivo.

Amino Acid Sequence↗
PubMed2002

Transplantation for cystic fibrosis: outcome following early liver transplantation.

BACKGROUND AND AIM: Life expectancy in patients with cystic fibrosis (CF) has recently improved due to numerous factors, including a multidisciplinary approach to their management. Prolonged survival may have led to an increasing impact of liver disease on the prognosis of CF patients. The aim of this study was to assess the role of liver transplantation in patients with CF. METHODS: The factors influencing outcome in 24 patients (15 adults and nine children) with CF who have received single liver transplantation, triple heart-lung-liver transplantation (tx) or died while being assessed for triple grafting, were analyzed. RESULTS: Median age at tx in single liver recipients (13 years) was lower than in triple graft recipients (21 years) and those who died (23 years). All patients who received single liver tx made an excellent recovery, including significant improvement of their respiratory function (mean forced vital capacity (FVC) increased from 61% before transplantation to 82% of expected, 6-9 months after tx). Four out of five patients who received triple tx died (0-2 months) after operation. On the basis of our retrospective review, we propose modifications to an existing scoring system for liver tx assessment in CF by scoring additional points for elevated white blood count, bilirubin, and impaired pulmonary function. These changes will need to be evaluated prospectively to confirm their predictive value. CONCLUSIONS: Liver transplantation is effective therapy in young patients with cystic fibrosis, portal hypertension and hepatic dysfunction, and is indicated before a critical stage of deteriorating lung function is reached. In patients with both end-stage liver and lung disease, triple tx has a poor prognosis. Pre-emptive liver tx in younger patients with CF not only has a better outcome but improves lung function.

Adolescent↗
PubMed2002

Paracetamol poisoning unmasking factor VII deficiency.

We report on an 18-year-old woman who took an impulsive overdose of paracetamol. The admission international normalized ratio (INR) was prolonged which resulted in her being transferred to a specialist hepatology unit. Her clinical condition and laboratory parameters did not correlate; this prompted investigation into her coagulation profile, which revealed a factor VII deficiency and explained the observed abnormalities of an elevated INR, normal partial thromboplastin time and normal liver function. There are no other reports of factor VII deficiency being identified as a result of paracetamol overdose.

Acetaminophen↗