bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene frequencies of human platelet antigens in the Tunisian population
Authors: Mojaat N. , Halle L. , Proulle V. , Hmida S. , Ben Hamed L. , Boukef K. , Kaplan C. 
Published: March 2003

Abstract:Gene frequencies for the human platelet antigens HPA‐1, ‐3 and ‐5 in the Tunisian population were determined by polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) on 93 volunteer blood donors (78 were tested for HPA‐1, 90 for HPA‐3 and 93 for HPA‐5). This study shows the highest frequencies of the HPA‐1b (0.25) and HPA‐5b (0.22) yet recorded. These antigens are considered as markers of a high risk of platelet alloimmunisation in other populations, and for this reason particular attention should be paid in the case of pregnancy or blood transfusion in this population. The 9 base pair deletion located in intron 21 of the GPIIb gene associated with HPA‐3b determinant is present in this population. No individual showed the polymorphism associated with HPA‐1b (T→G at codon 40 of the GPIIIa).
Diversity is demonstrated in class I HLA‐A and HLA‐B alleles in Cameroon, Africa: description of HLA‐A*03012, *2612, *3006 and HLA‐B*1403, *4016, *4703
Authors: Ellis J.M. , Mack S.J. , Leke R.F.G. , Quakyi I. , Johnson A.H. , Hurley C.K. 
Published: March 2003

Abstract:To examine the genetic diversity in west Africa, class I HLA‐A and HLA‐B alleles of 92 unrelated individuals from two areas in the Cameroon, the capital Yaoundé and the village of Etoa, were identified by direct automated DNA sequencing of exons 2 and 3 of the HLA‐B locus alleles and sequence‐specific oligonucleotide probe (SSOP) and/or sequencing of the HLA‐A locus alleles. HLA‐A*2301 (18.7%), A*2902 (10.4%), B*5301 (10.9%), and B*5802 (10.9%) were the most frequently detected alleles, present in at least 10% of the population. A total of 30 HLA‐A locus and 33 HLA‐B locus alleles, including six novel alleles, were detected. The novel alleles were HLA‐A*03012, A*2612, A*3006 and HLA‐B*1403, B*4016, and B*4703. HLA‐B*4703 contains a novel amino acid sequence that is a combination of the first 5 amino acids of the Bw6 epitope and the last 2 residues of the Bw4 epitope. The addition of 6 alleles to the ever‐expanding number of known class I HLA alleles supports our hypothesis that extensive genetic diversity, including previously undescribed alleles, would be observed in this African population. In the Yaoundé population, the allele frequency distribution at the HLA‐A locus is consistent with distributions indicative of balancing selection. Extensive HLA‐A‐B haplotypes were observed in this population suggesting that only a fraction of the Cameroon HLA‐A‐B haplotype diversity has been observed.
The CTLA4/CD28 gene region on chromosome 2q33 confers susceptibility to celiac disease in a way possibly distinct from that of type 1 diabetes and other chronic inflammatory disorders
Authors: Torinsson Naluai Å. , Nilsson S. , Samuelsson L. , Gudjónsdóttir A.H. , Ascher H. , Ek J. , Hallberg B. , Kristiansson B. , Martinsson T. , Nerman O. , Sollid L.M. , Wahlström J. 
Published: March 2003

Abstract:The effect of the gene region on chromosome 2q33 containing the CD28 and the cytotoxic T‐lymphocyte associated (CTLA4) genes has been investigated in several diseases with chronic inflammatory nature. In addition to celiac disease (CD), type I diabetes, Grave’s disease, rheumatoid arthritis and multiple sclerosis have all demonstrated associations to the A/G single nucleotide polymorphism (SNP) in exon 1, position +49 of the CTLA4 gene. The purpose of this study was to investigate this gene region in a genetically homogeneous population consisting of 107 Swedish and Norwegian families with CD using genetic association and linkage methods. We found a significant association with preferential transmission of the A‐allele of the exon 1 +49 polymorphism by using the transmission disequilibrium test (TDT). Suggestive linkage of this region to CD was moreover demonstrated by non‐parametric linkage (NPL) analysis giving a NPL‐score of 2.1. These data strongly indicates that the CTLA4 region is a susceptibility region in CD. Interestingly, of the several chronic inflammatory diseases that exhibit associations to the CTLA4 +49 A/G dimorphism, CD appears to be the only disease associated to the A allele. This suggests that the +49 alleles of the CTLA4 gene are in linkage disequilibrium with two distinct disease predisposing alleles with separate effects. The peculiar association found in the gut disorder CD may possibly relate to the fact that the gastrointestinal immune system, in contrast to the rest of the immune system, aims to establish tolerance to foreign proteins.
A new B‐chain mutant of insulin: comparison with the insulin crystal structure and role of sulfonate groups in the B‐chain structure
Authors: Dupradeau F.‐Y. , Le Flem G. , Richard T. , Monti J.‐P. , Oulyadi H. , Prigent Y. 
Published: March 2003

Abstract: The solution structure of a new B‐chain mutant of bovine insulin, in which the cysteines B7 and B19 are replaced by two serines, has been determined by circular dichroism, 2D‐NMR and molecular modeling. This structure is compared with that of the oxidized B‐chain of bovine insulin [Hawkins et al. (1995) Int. J. Peptide Protein Res.46, 424–433]. Circular dichroism spectroscopy showed in particular that a higher percentage of helical secondary structure for the B‐chain mutant is estimated in trifluoroethanol solution in comparison with the oxidized B‐chain. 2D‐NMR experiments confirmed, among multiple conformations, that the B‐chain mutant presents defined secondary structures such as a α‐helix between residues B9 and B19, and a β‐turn between amino acids B20 and B23 in aqueous trifluoroethanol. The 3D structures, which are consistent with NMR data and were obtained using a simulated annealing protocol, showed that the tertiary structure of the B‐chain mutant is better resolved and is more in agreement with the insulin crystal structure than the oxidized B‐chain structure described by Hawkins et al. An explanation could be the presence of two sulfonate groups in the oxidized insulin B‐chain. Either by their charges and/or their size, such chemical groups could play a destructuring effect and thus could favor peptide flexibility and conformational averaging. Thus, this study provides new insights on the folding of isolated B‐chains.
Productive human immunodeficiency virus‐1 infection of epithelial cell lines of salivary gland origin
Authors: Han Y. , Ventura C. L. , Black K. P. , Cummins J. E. , Hall S. D. , Jackson S. 
Published: March 2003

To ascertain whether epithelial cells of oral cavity origin may be infected with human immunodeficiency virus (HIV‐1), a study to determine susceptibility to infection of salivary gland epithelial cell lines (HSY and HSG) was undertaken. Because of the potential for oral‐genital transmission, an endometrial cell line, HEC‐1, was also studied. Epithelial cell monolayers were infected with cell‐free HTLVIIIB or a primary HIV‐1 isolate. Several lines of evidence indicated that inoculation of these cell lines with HIV‐1 led to productive infection: 1) p24 antigen was present in supernatants, with levels peaking on days 3–4; 2) provirus was found in cells by polymerase chain reaction; 3) virions present in supernatants were infectious as confirmed by coculture with the T‐lympho‐blastoid line CEM‐NKr. Following a period of virus production, HIV‐1 entered a latency phase over 10 weeks. All epithelial cell lines were positive for galactosylceramide (GalC) and CXCR4. HSY was weakly positive for surface CD4, and also expressed mRNA for CD4 and CCR5, as did HEC‐1. Blocking studies indicated that anti‐GalC, but not anti‐CD4, significantly reduced productive infection, and that regulated on activation normal T cell expressed and secreted (RANTES) but not stromal cell–derived factor (SDF‐1) could partially block infection of the M‐tropic primary isolate. These results suggest that epithelial cells in the oral cavity and the genital tract might be targets of HIV‐1 and potentially serve as a mediator of systemic infection.
Atorvastatin treatment for hyperlipidemia in pediatric renal transplant recipients
Authors: Argent Elizabeth , Kainer Gad , Aitken Maggie , Rosenberg Andrew R. , Mackie Fiona E. 
Published: March 2003

Abstract: The objective of this prospective study was to determine the prevalence of hyperlipidemia in our pediatric renal transplant patients and to treat those with persistently elevated cholesterol and/or low‐density lipoprotein (LDL) levels. All patients with a functioning renal allograft for greater than 6 months were studied (n = 18). Patients with cholesterol and/or LDL levels greater than the 95th percentile (n = 9) were commenced on an HMG‐CoA reductase inhibitor, Atorvastatin and monitoring was performed for efficacy and adverse effects. Total serum cholesterol was elevated in 11 of 18 (61%) and triglyceride (TG) was elevated in 12 of 18 (67%) patients. Atorvastatin treatment was effective with a mean percentage reduction of total cholesterol of 41 ± 10% (p < 0.01 vs. before treatment), LDL 57 ± 7% (p < 0.01 vs. before treatment) and TG 44 ±25% (p = 0.05 vs. before treatment). No adverse effects on allograft function or cyclosporin levels were experienced. Hyperlipidemia is a common problem and Atorvastatin is a safe and effective treatment in pediatric renal transplant recipients.
Increased expression of cytotoxic effector molecules: Different interpretations for steroid‐based and steroid‐free immunosuppression
Authors: Satterwhite Thomas , Chua Mei‐Sze , Hsieh Szu‐Chuan , Chang Stella , Scandling John , Salvatierra Oscar , Sarwal Minnie M. 
Published: March 2003

Abstract: Cytotoxic T lymphocyte (CTL) effector molecules have been studied as markers of acute rejection in renal allograft recipients on steroid‐based immunosuppression. We hypothesized that basal CTL gene expression may vary with time post‐transplantation as well as with different immunosuppression protocols (steroid‐based or steroid‐free). Variations in CTL gene expression may thus impact on the ability to predict acute allograft rejection. We used the non‐invasive method of quantitative competitive‐reverse transcription‐polymerase chain reaction (QC‐RT‐PCR) to quantify the amounts of CTL effector molecules (granulysin, GL; perforin, P; granzyme B, GB) in serial peripheral blood lymphocyte (PBL) samples from steroid‐free and steroid‐based adult and pediatric renal allograft recipients. Patients on both protocols were clinically monitored by protocol biopsies at 1, 3, 6, and 12 months post‐transplantation and for graft function at 1 yr post‐transplantation in a separate clinical study. Steroid‐free patients with stable graft function showed an increase in GL, P, and GB gene expression over time post‐transplantation with the increase being seen largely by the first post‐transplant month. A further increase in GL expression was noted at the end of the first post‐transplant year in the absence of acute rejection, whereas GB and P levels were unchanged. At comparative time‐points post‐transplantation, CTL genes were found to be higher in steroid‐free patients with stable graft function, compared to steroid‐based recipients with either clinically stable graft function or acute rejection. This study suggests that levels of CTL gene expression, although important in a steroid‐based regimen to monitor the risk of acute rejection, may not be similarly applied in patients on steroid‐free immunosuppression. The early increase in levels seen in steroid‐free patients appears to correlate with the total absence of steroids. As steroid‐free patients seem to have a lower incidence of acute rejection and better long‐term graft function at 1 yr, the early increase in CTL genes in the absence of acute rejection may suggest an early adaptive immune activation response, promoting early graft acceptance in this protocol.
DNA fragmentation in cereal roots indicative of programmed root cortical cell death
Authors: Liljeroth Erland , Bryngelsson Tomas 
Published: March 2003

In cereals, a progressively increasing root cortical cell death (RCD) occurs from the root tip and upwards when measured with vital staining methods. In this study, nuclear DNA fragmentation was studied in seminal root segments of wheat and barley in order to investigate if the cell death resembled apoptosis. The fraction of cells with TUNEL‐positive nuclei increased gradually with increasing root age in both the cortex and the stele. Southern analysis showed a typical ladder pattern, indicating nucleosomal fragmentation already in 2‐day‐old root segments, and this became more pronounced in older root segments. DNA fragmentation appeared to be more extensive in wheat than in barley roots. These results confirm earlier studies, where RCD has been found to be earlier initiated and to proceed at a faster rate in wheat. The characteristic DNA fragmentation found in the roots indicates programmed cell death with mechanistic similarities to apoptosis. Ultrastructural examination of nuclei in cortex cells with transmission electron microscopy revealed an increased chromatin condensation in older roots, particularly in wheat.In addition, we found nucleosomal DNA ladders in young leaf tissue from wheat but not from barley.
Rice receptor for chitin oligosaccharide elicitor does not couple to heterotrimeric G‐protein: Elicitor responses of suspension cultured rice cells from Daikoku dwarf (d1) mutants lacking a functional G‐protein α‐subunit
Authors: Tsukada Koji , Ishizaka Masumi , Fujisawa Yukiko , Iwasaki Yukimoto , Yamaguchi Takeshi , Minami Eiichi , Shibuya Naoto 
Published: March 2003

We present evidence that the rice receptor for N‐acetylchitooligosaccharide elicitor does not couple to heterotrimeric G‐protein (G‐protein), one of the most important signal transducers from the cell surface to down‐stream effectors in various cellular responses of many organisms. Using mutant rice cells lacking functional G‐protein α‐subunit, cellular responses of suspension‐cultured rice cells derived from Daikoku dwarf (d1) mutants that were shown to contain mutations in the coding region of the G‐protein α‐subunit (Fujisawa et al. 1999) to N‐acetylchitooligosaccharide (oligochitin) elicitor were compared with those of the corresponding parent cell lines. All the elicitor‐induced cellular responses, such as medium alkalinization, generation of reactive oxygen species, expression of early responsive genes, PAL and PR genes, and production of phytoalexin, were basically identical in the mutant and wild type cell lines. Considering the reported presence of a single copy gene for the G‐protein α‐subunit in many plant species including rice, these results strongly support the above conclusion.
Ly49 and CD94/NKG2: developmentally regulated expression and evolution
Authors: Takei Fumio , McQueen Karina L. , Maeda Motoi , Wilhelm Brian T. , Lohwasser Stefan , Lian Rebecca H. , Mager Dixie L. 
Published: March 2003

Summary: Murine natural killer (NK) cells express two families of MHC class I‐specific receptors, namely the Ly49 family and CD94/NKG2 heterodimers. Stochastic co‐expression of these receptors generates diverse receptor repertoires in adult NK‐cell populations, whereas fetal NK cells have much more limited receptor diversity as they mostly express CD94/NKG2A but not Ly49. These receptors are also expressed on CD8+ T cells and NK1.1+ T cells and regulate their functions, but their expression pattern on NK cells is significantly different from those on T cells. Thus, expression of Ly49 and CD94/NKG2 is developmentally regulated. NK cells acquire the Ly49 family of receptors in an orderly manner as they differentiate from bone marrow progenitors in vitro. Similarly, acquisition of CD94 and NKG2 by NK cells as they differentiate from embryonic stem cells is also orderly. To gain insight into the mechanisms regulating Ly49 expression, potential regulatory regions of several Ly49 genes have been examined. Ly49 genes with different expression patterns have remarkably similar sequences in the putative regulatory regions. Finally, a functional Ly49 gene has been identified in baboon, and primate comparisons suggest that functional extinction of the Ly49 gene in the human lineage seems to have been a relatively recent event.This research was supported by the National Cancer Institute of Canada and the Medical Research Council of Canada with core support from the BC Cancer Agency. KM and BW were supported by studentships from the University of British Columbia and the National Science and Engineering Research Council of Canada. RL is a recipient of a Leukemia Research Fund of Canada fellowship. SL was supported by the Deutsche Forschungsgemeinschaft.
Human cytomegalovirus and natural killer‐mediated surveillance of HLA class I expression: a paradigm of host–pathogen adaptation
Authors: López‐Botet Miguel , Llano Manuel , Ortega Mara 
Published: March 2003

Summary: Among various strategies to evade the host immune response, some viruses like human cytomegalovirus (HCMV) interfere with surface MHC class I expression and antigen presentation to T lymphocytes. The ability of natural killer (NK) cells to detect MHC class I molecules through inhibitory receptors can be envisaged as an adaptation of the immune system for responding to such pathological alterations. To fulfil that role, rodents use members of the Ly49 C‐type lectin superfamily, whereas primates employ killer immunoglobulin‐like receptors and the immunoglobulin‐like transcript 2/leucocyte immunoglobulin‐like receptor‐1 receptor. CD94/NKG2 lectin‐like heterodimers represent the most conserved receptor system for MHC class I molecules; by interacting with human HLA‐E or murine Qa‐1b, CD94/NKG2A inhibitory receptors broadly probe the biosynthesis pathway of other class I molecules. Reciprocally, HCMV has developed mechanisms to evade the NK response while modulating HLA class Ia expression. The ability of HCMV to maintain surface levels of HLA‐E and to express an HLA class I surrogate (UL18) are herein discussed in the context of the interplay with human NKR systems.This work was supported by grants FIS 00/0181 and SAF98‐0006. We thank Dr A. Angulo for helpful discussion.
Synaptotagmin regulates mast cell functions
Authors: Baram Dana , Mekori Yoseph A. , Sagi‐Eisenberg Ronit 
Published: March 2003

Summary: Synaptotagmin(s) (Syts), are products of a gene family implicated in the control of Ca2+‐dependent exocytosis. Mast cells, specialized secretory cells that release mediators of inflammatory and allergic reactions in a process of regulated exocytosis, express Syt homologues and SNAREs (Soluble NSF Attachment proteins Receptors), which together with Syt constitute the core complex which mediates exocytotic vesicle docking and fusion. Rat basophilic leukemia cells (RBL‐2H3), a tumor analogue of mucosal mast cells, express the Syt homologues Syt II, Syt III and Syt V. Expression of Syt I, the neuronal Ca2+ sensor, in the RBL cells, resulted in its targeting to secretory granules and in prominent potentiation and acceleration of Ca2+‐dependent exocytosis. Syt II is localized to an amine‐free lysosomal compartment, which is also subjected to regulated exocytosis. Lysosomal exocytosis is negatively regulated by Syt II: overexpression of Syt II inhibited Ca2+‐triggered exocytosis of lysosomes, while suppression of Syt II expression markedly potentiated this release. These findings implicate Syt homologues as key regulators of mast cell function.We thank Drs. T.C. Sudhof, R.H. Scheller and M. Takahashi for their generous gifts of antibodies and cDNAs.
The roles of membrane microdomains (rafts) in T cell activation
Authors: Hor̆ejs̆í Václav 
Published: March 2003

Summary:Detergent‐resistant membrane microdomains enriched in sphingolipids, cholesterol and glycosylphosphatidylinositol‐anchored proteins play essential roles in T cell receptor (TCR) signaling. These ‘membrane rafts’ accumulate several cytoplasmic lipid‐modified molecules, including Src‐family kinases, coreceptors CD4 and CD8 and transmembrane adapters LAT and PAG/Cbp, essential for either initiation or amplification of the signaling process, while most other abundant transmembrane proteins are excluded from these structures. TCRs in various T cell subpopulations may differ in their use of membrane rafts. Membrane rafts also seem to be involved in many other aspects of T cell biology, such as functioning of cytokine and chemokine receptors, adhesion molecules, antigen presentation, establishing cell polarity or interaction with important pathogens. Although the concept of membrane rafts explains several diverse biological phenomena, many basic issues, such as composition, size and heterogeneity, under native conditions, as well as the dynamics of their interactions with TCRs and other immunoreceptors, remain unclear, partially because of technical problems.
Artificial and bioartificial support systems for liver failure: a Cochrane Hepato‐Biliary Group Protocol
Authors: Liu Jianping , Kjaergard Lise Lotte , Als‐Nielsen Bodil , Gluud Christian 
Published: March 2003

Abstract: Aims/Background: Liver support systems may bridge patients to liver transplantation or recovery from liver failure. This review is to evaluate the beneficial and harmful effects of artificial and bioartificial support systems for acute and acute‐on‐chronic liver failure.Data Sources: Randomized trials on any support system versus standard medical therapy will be included irrespective of publication status or language. Non‐randomized studies are included in explorative analyses. Trials will be identified through bibliographies, correspondence with original investigators, and electronic searches (Cochrane Hepato‐Biliary Group Controlled Trials Register, Cochrane Controlled Trials Register, MEDLINE, EMBASE, and The Chinese Biomedical Database).Methods of the review: The extracted data will include characteristics of trials, patients, interventions, and all outcome measures. Methodological quality will be assessed by the randomization, follow up, and blinding. The RevMan and STATA will be used for statistical analyses. Sources of heterogeneity and methodological quality in the assessment of the primary outcome will be explored by sensitivity analyses and meta‐regression.