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Piotr Milkiewicz

Publications and source records attributed to Piotr Milkiewicz.

11 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↗
PubMed2005

Primary biliary cirrhosis in a patient with Turner syndrome.

An increased prevalence of X chromosome monosomy has recently been demonstrated in patients with primary biliary cirrhosis (PBC). Chronic cholestasis of unknown etiology is a common clinical feature in patients with Turner syndrome who reach the fourth and fifth decades of life. A 37-year-old patient with Turner syndrome who presented with clinical and biochemical features of chronic cholestasis is described. Subsequent investigations confirmed the diagnosis of PBC. The patient did not respond to the medical treatment and was referred for liver transplant assessment. The present case may support the importance of X chromosome genes in the development of genetic predisposition to PBC, and emphasizes the necessity for a systematic study of the prevalence of PBC in patients with Turner syndrome.

Adult↗
PubMed2005

Diffuse skin reaction in patient with hepatitis B, treated with two different formulations of pegylated interferon.

Diffuse skin reactions, commonly leading to discontinuation of the treatment, have been reported in patients with hepatitis C treated with interferon. They were not as yet described in patients treated with a newer formulation of interferon, namely, pegylated interferon (PegINF). A 37-year-old male patient with viral hepatitis B developed a diffuse urticarial skin reaction during treatment with two different forms of PegINF. Despite the skin reaction, the treatment was continued, and the patient responded very well to topical steroids and antihistamines. The present report suggests that despite the severity of reaction, withdrawal of PegINF may not always be required because this particular skin reaction responded well to symptomatic treatment. This is important, because discontinuation of PegINF may decrease the chance of achieving a sustained virological response in patients with viral hepatitis.

Adult↗
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↗
PubMed2003

Early results of a new liver transplant program in Szczecin, Poland.

New liver transplant programs have usually been associated with a significant learning curve. This learning curve, however, can be minimized or avoided if certain conditions are met. In this paper we describe the establishment of a new liver transplant program in Szczecin, Poland and present its early results. Four members of the team underwent training in clinical liver transplantation in major centers in Europe. Transplant protocols were then adopted, all the necessary facilities set up, and multidisciplinary team created. Between February 2002 and August 2003, 22 adult orthotopic liver transplantations (OLT) were performed in 21 patients (13 male; mean age 46.3 years; range 33-62), including I retransplant for early hepatic artery thrombosis. Eighteen (86%) patients are alive between 4 and 22 (median 11) months after OLT. Seventeen patients have normal liver function and 14 of them have resumed full life activity. Three patients died: one of bacterial peritonitis (day 6), one of chronic rejection with allograft failure (month 4) and one following massive stroke (month 10). Surgical complications occurred in 7 patients (33%). We believe that proper training of vital team members at established transplant centers with good results, availability of adequate equipment and all the facilities required with strict adherence to transplant protocols are all paramount for a successful start of a liver transplant program.

Adult↗
PubMed2002

Obstetric cholestasis.

Explore the source record for details and available documents.

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↗
PubMedDate not supplied

Coordinate regulation of hepatic bile acid oxidation and conjugation by nuclear receptors.

Bile acids play important functions in the maintenance of bile acid homeostasis. However, due to their detergent properties, these acids are inherently cytotoxic and their accumulation in liver is associated with hepatic disorders such as cholestasis. During their enterohepatic circulation, bile acids undergo several metabolic alterations, including amidation, hydroxylation, sulfonation, and glucuronidation. Most of these transformations facilitate the excretion of bile acids into the bile (amidation and sulfonation) or into the blood for subsequent urinary elimination (hydroxylation, sulfonation, and glucuronidation). In this review, the role of various nuclear receptors and transcription factors in the expression of bile acid detoxification enzymes is summarized. In particular, the coordinate manner in which the xenobiotic sensors pregnane X receptor and constitutive androstane receptor, the lipid sensors liver X receptor, farnesoid X receptor, peroxisome proliferator-activated receptor alpha, and vitamin D receptor, and the orphan receptors hepatocyte nuclear factor 4alpha and small heterodimer partner regulate bile acid detoxification is detailed. Finally, we conclude by discussing the importance of these transcription factors as promising drug targets for the correction of cholestasis.

Animals↗