N. Tajik - Academia.edu (original) (raw)
Papers by N. Tajik
Post-prandial hyperlipidemia is a risk factor for atherosclerosis. Fasting plasma apo B48 is a pr... more Post-prandial hyperlipidemia is a risk factor for atherosclerosis. Fasting plasma apo B48 is a promising marker of post-prandial lipid metabolism. We investigated the association of apo B48 with oxidized LDL (ox-LDL), and the presence of peripheral arterial disease (PAD) in diabetics with and without kidney disease (DKD). Patients and Methods: 40 age and sex-matched subjects were enrolled, 20 with DKD and 20 without, defined by albumin excretion rate and estimated glomerular filtration rate (eGFR by Cockroft-Gault formula). Lipoproteins, subclinical PAD by ankle-brachial index (ABI), post-prandial lipaemia by fasting apo B48 (ELISA), levels of ox-LDLs (ELISA), albuminuria and eGFR were evaluated. Results: Demographic and anthropometric data, glycaemic control and lipid profile were similar between patients with and without nephropathy. Apo B48 was significantly associated with TG content in VLDL, LDL and HDL (all p < 0.01), with plasma ox-LDL (p = 0.016), and glycated haemoglobin A1c (p < 0.01). Apo B48 (p < 0.01) and ox-LDL (p < 0.05) were higher in patients with eGFR < 60 ml/min vs. those with eGFR 60. Progressively lower eGFR was associated with increasing apo B48 (p = 0.014, non-parametric ANOVA). Estimated-GFR <60 ml/min was associated with significantly lower ABI vs eGFR >60 ml/min. Levels of ox-LDL were significantly lower in patients on statin vs off statin (P < 0.05) regardless of eGFR. Conclusions: This study provides evidence of a significant association between apo B48, ox-LDL and a proatherogenic lipid phenotype in patients with DKD, suggesting a significant effect of statins on LDL oxidation in these patients
Background: In addition to Human Leukocyte Antigens (HLA) compatibility, gene polymorphisms in cy... more Background: In addition to Human Leukocyte Antigens (HLA) compatibility, gene polymorphisms in cytokines might also be important in the quality of allogeneic im- mune response. Objective: To evaluate the influence of HLA-DR matching and a number of cytokine gene polymorphisms on acute rejection after living-unrelated donor (LURD) kidney transplantation. Methods: A total of 42 renal transplants per- formed at Hashemi Nejad Kidney Hospital (Tehran/Iran) and followed up for 3 months post-transplantation were included. Using PCR-SSP, HLA-DR alleles (DR1- 18) of recipients and donors and gene polymorphisms in TNF-α, TGF-β1, IL-10, IL- 6, and IFN-γ of recipients were determined. Results: Acute rejection was observed in 11(26.2%) of renal recipients. The frequency of one and two HLA-DR mismatches in rejector group was 2(18.2%) and 9(81.8%) and in non-rejector group was 13(41.9%) and 17(54.8%), respectively. HLA-DR incompatibility was not signifi- cantly higher in rejector (1.82 0.40) compa...
Tissue Antigens, 2007
Intercellular adhesion molecule 1 (ICAM-1) is a cell surface glycoprotein member of the immunoglo... more Intercellular adhesion molecule 1 (ICAM-1) is a cell surface glycoprotein member of the immunoglobulin superfamily and is actively involved in immune and inflammatory responses. We introduce a novel polymerase chain reaction-sequence-specific primers (PCR-SSP) method for rapid and simultaneous genotyping of ICAM-1 G241R and K469E polymorphisms. In a total of 184 DNA samples that have been previously analyzed for these polymorphisms using polymerase chain reaction-restriction fragment length polymorphism technique, re-genotyping of all samples with this new assay showed accurate and reproducible results. As PCR-SSP-based genotyping protocols are more convenient and cost-effective to do, it could therefore offer a valuable tool for assessment of ICAM-1 polymorphisms to which more confirmatory studies are needed.
Tissue Antigens, 2009
Killer-cell immunoglobulin-like receptors (KIR) are a family of inhibitory and activating recepto... more Killer-cell immunoglobulin-like receptors (KIR) are a family of inhibitory and activating receptors that are expressed mainly by natural killer cells. The KIR gene family is highly polymorphic, and its genomic diversity is achieved through differences in gene content as well as allelic polymorphism. The number of KIR loci has been reported to be various among individuals and therefore resulting in different KIR haplotypes. This study represents the first report on the distribution of 17 presently defined KIR genes and pseudogenes in the Iranian population. In our study, 200 unrelated healthy individuals were KIR typed by a novel polymerase chain reaction-sequence-specific primers genotyping assay, and Iranian KIR genes distribution was compared with other ethnic groups. Over all, twenty-six different genotype profiles were found in our population and all KIR genes were observed. The most frequent non-framework KIR genes detected in our population were KIR2DL1 (96.5%), KIR3DL1 (91.5%), KIR2DS4 (91.5%) and the pseudogene KIR2DP1 (96.5%). The most commonly observed KIR genotype in Iranian population with a frequency of 27.5% consisted of KIR2DL1, KIR2DL3, KIR2DL4, KIR3DL1, KIR3DL2, KIR3DL3 and KIR2DS4 genes and the pseudogenes KIR2DP1 and KIR3DP1, which was compatible with a homozygote group-A haplotype. In addition, we found a new genotype (KIR2DL2, KIR2DL4, KIR2DL5, KIR3DL2, KIR3DL3, KIR2DS2, KIR2DS3, KIR2DS5, KIR3DS1 and KIR3DP1) in our samples. The results show that distribution of KIR genes in the Iranian population has common general features with the Caucasian populations studied before but still with unique, decreased or increased frequencies of several loci.
International Journal of Immunogenetics, 2010
Natural killer (NK) cells eliminate infected and transformed cells while still are self-tolerant.... more Natural killer (NK) cells eliminate infected and transformed cells while still are self-tolerant. Interactions of the independently segregating Killer cell immunoglobulin-like receptors (KIR) and human leucocyte antigens (HLA) loci play a critical role in NK cell regulation. Different compound KIR-HLA genotypes can impart different thresholds of activation to the NK-cell repertoire and such genotypic variation has been found to confer altered risk in a number of human diseases including viral infections, autoimmune disorders, reproduction abnormalities and cancers. In this study, we presented a novel combined KIR-HLA polymerase chain reaction-sequence-specific primers genotyping assay for simultaneous determination of KIR genes and their three major HLA class I ligand groups (C1, C2, and Bw4). Moreover, known inhibitory and activating KIR + HLA (iKIR + HLA: 2DL2/3 + C1, 2DL1 + C2, 3DL1 + Bw4; and aKIR + HLA: 2DS2 + C1, 2DS1 + C2, 3DS1 + Bw4) combinations as well as co-inheritance of aKIR genes and iKIR + HLA pairs were analysed in a total of 200 unrelated healthy Iranian individuals. All tested subjects had at least one of the three iKIR + HLA pairs and the frequencies of various inhibitory combinations in the study group were: 31.5%, three iKIR + HLA pairs, 53.5%, two iKIR + HLA pairs, and 15%, 0ne iKIR + HLA pair. Furthermore, we revealed that majority of Iranians (69%) carry compound genotypes with greater number of inhibitory pairings than activating combinations (iKIR + HLA &amp;gt; aKIR + HLA). Conversely, iKIR + HLA &amp;lt; aKIR (45%) was dominant genotype in the study group. We conclude that selective evolutionary pressure has propensity to maintain KIR-HLA genotypes with more inhibitory combinations to guarantee self-tolerance. In contrast, existence of activating KIR genes without normal endogenous ligands, potentially arms the NK population for competent immunosurveillance and stronger defense against infections.
Iran J Immunol, Jun 1, 2010
Background: The HLA class I molecules serve as ligands for both T cell receptors and killer cell ... more Background: The HLA class I molecules serve as ligands for both T cell receptors and killer cell immunoglobulin-like receptors (KIRs). Objective: We investigated the HLAC and HLA-Bw4 alleles as well as KIRs expression on CD56 positive lymphocytes to evaluate whether these genes and molecules could influence Ankylosing spondylitis (AS) susceptibility, alone or in combination. Methods: We typed 40 AS patients and 40 normal controls for HLA-C asn80 (group 1) and HLA-C lys80 (group 2), HLA-B Bw4thero, HLA-B ...
Transplantation, 2008
The Presence of donor leukocytes in recipients of organ allograft has been shown even several yea... more The Presence of donor leukocytes in recipients of organ allograft has been shown even several years after transplantation. However, it remains unclear whether this donor cell microchimerism plays an effective role in allograft acceptance or is simply a consequence of immunosuppressive conditions in recipients. Objective: To study microchimerism in a group of kidney transplant recipients. Methods: In this study, the Peripheral Blood Microchimerism (PBM) after renal transplantation was retrospectively evaluated in 32 male-to-female recipients of living (unrelated) and cadaveric donor renal transplants. Using a Nested Polymerase Chain Reaction (Nested-PCR) amplification specific for SRY region of the Y chromosome, microchimerism was detected with a sensitivity of 1:1000000. Recipients were classified and compared according to the presence of PBM, acute and chronic rejection episodes, type of allotransplant, recipient and donor age at transplantation, previous male labor or blood transfusion, allograft function (serum creatinine level), and body mass index. Results: Among 32 recipients, 7 (21.9) were positive for PBM in multiple testing at different post-transplantation times. All microchimeric recipients had received kidney from living-unrelated donors. No significant difference was observed with regard to other parameters mentioned above. In addition, acute rejection rate in the microchimeric group was 3 (42%) versus 4 (16%) in the nonmicrochimeric recipients (not significant). Conclusion: Our results demonstrate better establishment of microchimerism after living donor kidney transplantation. However, concerning the true effect of microchimerism after renal transplantation doubt still persists; and it seems that microchimerism alone has no major protective role in renal allograft survival.
Post-prandial hyperlipidemia is a risk factor for atherosclerosis. Fasting plasma apo B48 is a pr... more Post-prandial hyperlipidemia is a risk factor for atherosclerosis. Fasting plasma apo B48 is a promising marker of post-prandial lipid metabolism. We investigated the association of apo B48 with oxidized LDL (ox-LDL), and the presence of peripheral arterial disease (PAD) in diabetics with and without kidney disease (DKD). Patients and Methods: 40 age and sex-matched subjects were enrolled, 20 with DKD and 20 without, defined by albumin excretion rate and estimated glomerular filtration rate (eGFR by Cockroft-Gault formula). Lipoproteins, subclinical PAD by ankle-brachial index (ABI), post-prandial lipaemia by fasting apo B48 (ELISA), levels of ox-LDLs (ELISA), albuminuria and eGFR were evaluated. Results: Demographic and anthropometric data, glycaemic control and lipid profile were similar between patients with and without nephropathy. Apo B48 was significantly associated with TG content in VLDL, LDL and HDL (all p < 0.01), with plasma ox-LDL (p = 0.016), and glycated haemoglobin A1c (p < 0.01). Apo B48 (p < 0.01) and ox-LDL (p < 0.05) were higher in patients with eGFR < 60 ml/min vs. those with eGFR 60. Progressively lower eGFR was associated with increasing apo B48 (p = 0.014, non-parametric ANOVA). Estimated-GFR <60 ml/min was associated with significantly lower ABI vs eGFR >60 ml/min. Levels of ox-LDL were significantly lower in patients on statin vs off statin (P < 0.05) regardless of eGFR. Conclusions: This study provides evidence of a significant association between apo B48, ox-LDL and a proatherogenic lipid phenotype in patients with DKD, suggesting a significant effect of statins on LDL oxidation in these patients
Background: In addition to Human Leukocyte Antigens (HLA) compatibility, gene polymorphisms in cy... more Background: In addition to Human Leukocyte Antigens (HLA) compatibility, gene polymorphisms in cytokines might also be important in the quality of allogeneic im- mune response. Objective: To evaluate the influence of HLA-DR matching and a number of cytokine gene polymorphisms on acute rejection after living-unrelated donor (LURD) kidney transplantation. Methods: A total of 42 renal transplants per- formed at Hashemi Nejad Kidney Hospital (Tehran/Iran) and followed up for 3 months post-transplantation were included. Using PCR-SSP, HLA-DR alleles (DR1- 18) of recipients and donors and gene polymorphisms in TNF-α, TGF-β1, IL-10, IL- 6, and IFN-γ of recipients were determined. Results: Acute rejection was observed in 11(26.2%) of renal recipients. The frequency of one and two HLA-DR mismatches in rejector group was 2(18.2%) and 9(81.8%) and in non-rejector group was 13(41.9%) and 17(54.8%), respectively. HLA-DR incompatibility was not signifi- cantly higher in rejector (1.82 0.40) compa...
Tissue Antigens, 2007
Intercellular adhesion molecule 1 (ICAM-1) is a cell surface glycoprotein member of the immunoglo... more Intercellular adhesion molecule 1 (ICAM-1) is a cell surface glycoprotein member of the immunoglobulin superfamily and is actively involved in immune and inflammatory responses. We introduce a novel polymerase chain reaction-sequence-specific primers (PCR-SSP) method for rapid and simultaneous genotyping of ICAM-1 G241R and K469E polymorphisms. In a total of 184 DNA samples that have been previously analyzed for these polymorphisms using polymerase chain reaction-restriction fragment length polymorphism technique, re-genotyping of all samples with this new assay showed accurate and reproducible results. As PCR-SSP-based genotyping protocols are more convenient and cost-effective to do, it could therefore offer a valuable tool for assessment of ICAM-1 polymorphisms to which more confirmatory studies are needed.
Tissue Antigens, 2009
Killer-cell immunoglobulin-like receptors (KIR) are a family of inhibitory and activating recepto... more Killer-cell immunoglobulin-like receptors (KIR) are a family of inhibitory and activating receptors that are expressed mainly by natural killer cells. The KIR gene family is highly polymorphic, and its genomic diversity is achieved through differences in gene content as well as allelic polymorphism. The number of KIR loci has been reported to be various among individuals and therefore resulting in different KIR haplotypes. This study represents the first report on the distribution of 17 presently defined KIR genes and pseudogenes in the Iranian population. In our study, 200 unrelated healthy individuals were KIR typed by a novel polymerase chain reaction-sequence-specific primers genotyping assay, and Iranian KIR genes distribution was compared with other ethnic groups. Over all, twenty-six different genotype profiles were found in our population and all KIR genes were observed. The most frequent non-framework KIR genes detected in our population were KIR2DL1 (96.5%), KIR3DL1 (91.5%), KIR2DS4 (91.5%) and the pseudogene KIR2DP1 (96.5%). The most commonly observed KIR genotype in Iranian population with a frequency of 27.5% consisted of KIR2DL1, KIR2DL3, KIR2DL4, KIR3DL1, KIR3DL2, KIR3DL3 and KIR2DS4 genes and the pseudogenes KIR2DP1 and KIR3DP1, which was compatible with a homozygote group-A haplotype. In addition, we found a new genotype (KIR2DL2, KIR2DL4, KIR2DL5, KIR3DL2, KIR3DL3, KIR2DS2, KIR2DS3, KIR2DS5, KIR3DS1 and KIR3DP1) in our samples. The results show that distribution of KIR genes in the Iranian population has common general features with the Caucasian populations studied before but still with unique, decreased or increased frequencies of several loci.
International Journal of Immunogenetics, 2010
Natural killer (NK) cells eliminate infected and transformed cells while still are self-tolerant.... more Natural killer (NK) cells eliminate infected and transformed cells while still are self-tolerant. Interactions of the independently segregating Killer cell immunoglobulin-like receptors (KIR) and human leucocyte antigens (HLA) loci play a critical role in NK cell regulation. Different compound KIR-HLA genotypes can impart different thresholds of activation to the NK-cell repertoire and such genotypic variation has been found to confer altered risk in a number of human diseases including viral infections, autoimmune disorders, reproduction abnormalities and cancers. In this study, we presented a novel combined KIR-HLA polymerase chain reaction-sequence-specific primers genotyping assay for simultaneous determination of KIR genes and their three major HLA class I ligand groups (C1, C2, and Bw4). Moreover, known inhibitory and activating KIR + HLA (iKIR + HLA: 2DL2/3 + C1, 2DL1 + C2, 3DL1 + Bw4; and aKIR + HLA: 2DS2 + C1, 2DS1 + C2, 3DS1 + Bw4) combinations as well as co-inheritance of aKIR genes and iKIR + HLA pairs were analysed in a total of 200 unrelated healthy Iranian individuals. All tested subjects had at least one of the three iKIR + HLA pairs and the frequencies of various inhibitory combinations in the study group were: 31.5%, three iKIR + HLA pairs, 53.5%, two iKIR + HLA pairs, and 15%, 0ne iKIR + HLA pair. Furthermore, we revealed that majority of Iranians (69%) carry compound genotypes with greater number of inhibitory pairings than activating combinations (iKIR + HLA &amp;gt; aKIR + HLA). Conversely, iKIR + HLA &amp;lt; aKIR (45%) was dominant genotype in the study group. We conclude that selective evolutionary pressure has propensity to maintain KIR-HLA genotypes with more inhibitory combinations to guarantee self-tolerance. In contrast, existence of activating KIR genes without normal endogenous ligands, potentially arms the NK population for competent immunosurveillance and stronger defense against infections.
Iran J Immunol, Jun 1, 2010
Background: The HLA class I molecules serve as ligands for both T cell receptors and killer cell ... more Background: The HLA class I molecules serve as ligands for both T cell receptors and killer cell immunoglobulin-like receptors (KIRs). Objective: We investigated the HLAC and HLA-Bw4 alleles as well as KIRs expression on CD56 positive lymphocytes to evaluate whether these genes and molecules could influence Ankylosing spondylitis (AS) susceptibility, alone or in combination. Methods: We typed 40 AS patients and 40 normal controls for HLA-C asn80 (group 1) and HLA-C lys80 (group 2), HLA-B Bw4thero, HLA-B ...
Transplantation, 2008
The Presence of donor leukocytes in recipients of organ allograft has been shown even several yea... more The Presence of donor leukocytes in recipients of organ allograft has been shown even several years after transplantation. However, it remains unclear whether this donor cell microchimerism plays an effective role in allograft acceptance or is simply a consequence of immunosuppressive conditions in recipients. Objective: To study microchimerism in a group of kidney transplant recipients. Methods: In this study, the Peripheral Blood Microchimerism (PBM) after renal transplantation was retrospectively evaluated in 32 male-to-female recipients of living (unrelated) and cadaveric donor renal transplants. Using a Nested Polymerase Chain Reaction (Nested-PCR) amplification specific for SRY region of the Y chromosome, microchimerism was detected with a sensitivity of 1:1000000. Recipients were classified and compared according to the presence of PBM, acute and chronic rejection episodes, type of allotransplant, recipient and donor age at transplantation, previous male labor or blood transfusion, allograft function (serum creatinine level), and body mass index. Results: Among 32 recipients, 7 (21.9) were positive for PBM in multiple testing at different post-transplantation times. All microchimeric recipients had received kidney from living-unrelated donors. No significant difference was observed with regard to other parameters mentioned above. In addition, acute rejection rate in the microchimeric group was 3 (42%) versus 4 (16%) in the nonmicrochimeric recipients (not significant). Conclusion: Our results demonstrate better establishment of microchimerism after living donor kidney transplantation. However, concerning the true effect of microchimerism after renal transplantation doubt still persists; and it seems that microchimerism alone has no major protective role in renal allograft survival.