Protein tyrosine phosphatase 1B (PTP1B) inhibits insulin signaling and, when overexpressed, plays a role in insulin resistance (Ahmad et al. 1997). We identified, in the 3' untranslated region of the PTP1B gene, a 1484insG variation that, in two different populations, is associated with several features of insulin resistance: among male individuals, higher values of the insulin resistance HOMA(IR) index (P=.006), serum triglycerides (P=.0002), and total/HDL cholesterol ratio (P=.025) and, among female individuals, higher blood pressure (P=.01). Similar data were also obtained in a family-based association study by use of sib pairs discordant for genotype (Gu et al. 2000). Subjects carrying the 1484insG variant showed also PTP1B mRNA overexpression in skeletal muscle (6,166 plus minus 1,879 copies/40 ng RNA vs. 2,983 plus minus 1,620; P<.01). Finally, PTP1B mRNA stability was significantly higher (P<.01) in human embryo kidney 293 cells transfected with 1484insG PTP1B, as compared with those transfected with wild-type PTP1B. Our data indicate that the 1484insG allele causes PTP1B overexpression and plays a role in insulin resistance. Therefore, individuals carrying the 1484insG variant might particularly benefit from PTP1B inhibitors, a promising new tool for treatment of insulin resistance (Kennedy and Ramachandran 2000).

A gene cloning strategy based on the screening of the Expressed Sequence Tags database (dbEST) using sequences of mitochondrial housekeeping proteins of yeast was employed to identify the cDNA encoding the precursor of the human mitochondrial RNA polymerase (h-mtRPOL). The 3831 bp h-mtRPOL cDNA is located on chromosome 19p13.3 and encodes a protein of 1230 amino acid residues. The protein sequence shows significant homologies with sequences corresponding to mitochondrial RNA polymerases from lower eukaryotes, and to RNA polymerases from several bacteriophages. The mitochondrial RNA polymerase carries out the central activity of mitochondrial gene expression and, by providing the RNA primers for replication-initiation, is also implicated in the maintenance and propagation of the mitochondrial genome. Genes involved in the control of mtDNA replication and gene expression are attractive candidates for human disorders due to abnormalities of nucleo-mitochondrial intergenomic signalling. The availability of the h-mtRPOL cDNA will allow us to test its role in mitochondrial pathology. In addition, we propose the 'cyberscreening' of dbEST, based on yeast/human cross-species comparison, as a powerful, simple, rapid and inexpensive method, that may accelerate several-fold the molecular dissection of the human mitochondrial proteome.

Purpose:To assess the transferability of the magnetic resonance imaging (MRI) multislice multiecho T2* technique for global and segmental measurement of iron overload in thalassemia patients. Materials and Methods:Multiecho T2* sequences were installed on six MRI scanners. Five healthy subjects (n ϭ 30) were scanned at each site; five thalassemia major (TM) patients were scanned at the reference site and were rescanned locally (n ϭ 25) within 1 month. T2* images were analyzed using previously validated software.Results: T2* values of healthy subjects showed intersite homogeneity. On TM patients, for global heart T2* values the correlation coefficient was 0.97, coefficients of variation (CoV s ) ranged from 0.04 -0.12, and intraclass coefficients (ICC s ) ranged from 0.94 -0.99. The mean CoV and ICC for segmental T2* distribution were 0.198 and 88, respectively. Conclusion:The multislice multiecho T2* technique is transferable among scanners with good reproducibility.

This study was aimed at the search of urinary biomarkers which might help to predict the clinical response of IgA nephropathy (IgAN) patients to angiotensin converting enzyme inhibitors (ACEi). First, we studied the urinary proteome of 18 IgAN patients (toward 20 healthy controls) who had been chronically treated with ACEi by using 2-D PAGE coupled to nano-HPLC-ESI-MS/MS analysis. We identified 3 proteins, kininogen (p = 0.02), inter-alpha-trypsin-inhibitor heavy chain 4 (35 kDa fragment) (p = 0.02) and transthyretin (p<0.0001), whose urinary excretion was different in IgAN patients' responders when compared to those who had not responded to ACEi. A reduction of daily proteinuria >50% and a stable renal function over time were used to classify patients as responders. Then, we adopted immunoblotting to confirm the predictive power of one of the above proteins, kininogen, in 20 patients with biopsy-proven IgAN, before starting any therapy. Thus, we confirmed that very low levels of kininogen urine excretion were indeed predictive of an inadequate or absent clinical response to ACEi therapy of IgAN patients, after 6-month follow-up. Concluding, the analysis of urine proteome of IgAN patients generated a set of proteins which distinguished subjects responsive to ACEi from those unresponsive to the inhibition of renin-angiotensin system (RAS).

ABO-incompatible (ABO-I) liver transplantation is a controversial issue because of the generally less favorable outcome as compared to compatible transplants. Encouraging results have been shown by the introduction of new strategies to reduce posttransplant-specific hemagglutinin (HA) titers with plasmapheresis, reinforced immunosuppression (IS), and the use of splenectomy. We describe a new protocol consisting of daclizumab (DAC) induction, mycophenolate mofetil (MMF)/tacrolimus (TAC)/steroids without splenectomy. Five recipients (mean age of 47 Ϯ 14 yr) undergoing ABO-I living donor liver transplantation (LDLT) were included in this protocol. Immunoadsorbent columns (Glycosorb ABO) were used for antigenspecific immunoadsorption (ASI). The median follow-up was 18.5 Ϯ 10.5 months. ASI was very efficient in lowering HA titers (mean log 2 immunoglobulin [Ig] M [IgM] and IgG values before and after ASI were 5.9 Ϯ 2.8 and 1.2 Ϯ 1.4 [P ϭ 0.0038] and 6.5 Ϯ 2.3 and 1.1Ϯ 1.9, respectively [P ϭ 0.0001]). Persisting low HA titers were observed over time. No sepsis nor cytomegalovirus infection episodes were recorded. Acute cellular rejection (ACR) occurred in 1 recipient responding to steroid pulse therapy. Two grafts were lost in 2 patients due to technical failure during the first postoperative month. We conclude that ASI using Glycosorb ABO, quadruple immunosuppression including DAC and MMF provide high efficiency to lower HA titers over time, avoiding the need for splenectomy. ABO-I LDLT can be performed with this adapted IS protocol. Liver Transpl 12: 1412Transpl 12: -1417Transpl 12: , 2006 See Editorial on Page 1324Liver transplantation across ABO barriers is a controversial issue. The risks for severe acute rejection episodes, vascular thrombosis, and bile duct necrosis are high and predict the outcome. Indeed, early reports showed 1-yr graft survival of 66% or 2-yr graft survival of 30% for ABO-I liver transplants compared to 76% for compatible procedures. The global 5-yr graft survival rate was not higher than 20%. [1][2][3] Since the role of preformed complement-fixing hemagglutinin (HA) has been demonstrated in mediating hyperacute or severe rejection, several therapeutic protocols were proposed to decrease HA titers when crossing ABO barriers. [4][5][6] These protocols were based principally on plasma exchange and reinforced immunosuppression (IS) with antithymocyte globulin, OKT 3 induction, or cyclophos-