Common polymorphisms of growth hormone: Growth hormone receptor axis in Turkish children with short stature

Objective: A single-nucleotide polymorphism of the growth hormone 1 gene, GH1IVS4+90A>T (rs2665802), associated with short stature and a polymorphism of the growth hormone receptor gene, exon 3 deleted variant, associated with increased responsiveness to growth hormone have been reported previously. We aimed to investigate the frequency of both polymorphisms and their correlation to height in Turkish short children. Also, we aimed to evaluate the effect of exon 3 deleted variant on response to 1-year growth hormone therapy. Materials and Methods: Children with idiopathic isolated growth hormone deficiency (n = 39) and with idiopathic short stature (n = 10) and 50 control subjects were evaluated for anthropo-metric parameters, annual growth velocity, and annual height gain. Growth hormone receptor gene polymorphisms were analyzed via multiplex polymerase chain reaction; growth hormone 1 gene polymorphism was analyzed via polymerase chain reaction and single-strand confor-mation polymorphism techniques. Results: The frequency of genotypes carrying the “A” allele was not significantly higher in the idiopathic isolated growth hormone deficiency group than in the idiopathic short stature and control groups (P = .03 for each). The exon 3 deleted variant genotype was significantly lower in the idiopathic short stature group compared to the control group (P = .01). There was no effect of exon 3 deleted variant, on response to the first-year growth hormone therapy. Conclusion: In Turkish population, no correlation was found between the “A” allele of GH1IVS4+90A>T polymorphism and idiopathic isolated growth hormone deficiency and short stature, and a significant negative correlation was found between exon 3 deleted variant and idiopathic short stature and short stature. Exon 3 deleted variant has no effect on response to growth hormone treatment.Istanbul Universit

Coexistence of K-ras mutations and HPV infection in colon cancer

BACKGROUND: Activation of the ras genes or association with human papillomavirus infection have been extensively studied in colorectal cancer. However, the correlation between K-ras mutations and HPV in colorectal cancer has not been investigated yet. In this study we aimed to investigate the presence of K-ras mutations and their correlation with HPV infection in colon cancer. METHODS: K-ras mutations were analyzed by a mutagenic PCR assay and digestion with specific restriction enzymes to distinguish the wild-type and mutant codons. HPV infection was analyzed by PCR amplification and hybridization with specific probes by Southern blotting. Stattistical analyses were performed by the chi-square and Fisher's exact tests RESULTS: HPV gene fragments were detected in 43 tumors and 17 normal tissue samples. HPV 18 was the prevalent type in the tumor tissue. A mutation at codon 12 of the K-ras gene was present in 31 patients. 56% of the HPV-positive tumors also harbored a K-ras mutation. Codon 13 mutations were not observed. These data indicate that infection with high risk HPV types and mutational activation of the K-ras gene are frequent events in colorectal carcinogenesis. CONCLUSION: Our findings suggest that mutational activation of the K-ras gene is a common event in colon carcinogenesis and that HPV infection may represent an important factor in the development of the premalignant lesions leading to the neoplastic phenotype

Detection of t(14;18) in turkish follicular lymphomas using the polymerase chain reaction.

A t(14;18) translocation is closely associated with the follicular lymphoma but is also seen in diffuse B cell lymphomas with a previous history of a follicular lymphoma as well as de novo diffuse lymphomas. Estimation of the frequency of t(14;18) in follicular lymphoma vary widely from 33 to 89%. Furthermore, no extensive data have been published on the frequency of t(14;18) in Turkish cases of follicular lymphoma. Representative tissue blocks from 67 patients with follicular lymphoma, 12 cases of diffuse large B cell lymphomas and 11 cases of reactive hyperplasias were examined for the presence of this translocation using PCR. DNA probes capable of detecting rearrangement at both the major and minor break point regions were employed. We could detect t(14;18) in 46 out of 67 cases (68.7%) of follicular and 25% of diffuse large B cell lymphomas. In follicular lymphomas 64.2% of these break points were at mbr and 4.5% were at the mcr region. Review of the literature showed that comparable results have been obtained previously using molecular techniques. Our data showed that despite the relative infrequency of follicular lymphomas in the Turkish population these lymphomas share a common molecular pathogenesis with involvement of bcl-2 gene and background incidence of such rearrangement is similar in all populations, regardless the incidence of folicular lymphoma

Lack of association between IL-1 beta/alpha gene polymorphisms and temporal lobe epilepsy with hippocampal sclerosis

Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is one of the most common medically intractable epilepsy syndromes and the pathogenesis of HS remains highly obscure. Recent studies demonstrated controversial results about the relationship between interleukin (IL) gene polymorphism and epilepsy in different ethnic groups. This correlation was investigated in Turkish patients with MTLE-HS. The allele distribution of IL-1alpha and IL-1beta in 47 patients of Turkish ancestry was determined and compared with 99 ethnically matched control subjects. Analysis of genotype frequencies between patients and controls showed no statistically significant difference (p>0.05). Our data suggest that IL-1alpha and IL-1beta gene polymorphisms do not act as a strong susceptibility factor for MTLE-HS in individuals of Turkish ancestry. PMID: 16546408 [PubMed - indexed for MEDLINE

Downregulation of NPRL2 in Colon Cancer

Downregulation of NPRL2 in Colon Cancer N. Buyru,1 İ.Hatemi2, İ.Aydin3, B.Yogurtcu1 1 Istanbul University Cerrahpasa Medicine Faculty Medical Biology Department 2 Istanbul University Cerrahpasa Medicine Faculty Department of Gastroenterology 3 Istanbul Training and Research Hospital Department of General Surgery Colorectal cancer is a major cause of cancer related death all around the world. Genetic and epigenetic factors affecting DNA methylation and gene expression are known to be involved in the development of CRC, but full range of genetic alterations and many key genes involved in the pathogenesis of CRC remain to be identified. NPRL2 is one of the candidate tumor suppressor genes identified in the human chromosome 3p21.3 region, which contains genetic abnormalities are frequently found in the early stages of various cancers. The aim of this study to evaluate the role of NPRL2 gene in the pathogenesis of colorectal cancer. Therefore we investigated NPRL2 mRNA expression in 55 normal and tumor colon tissue samples using quantitative real-time reverse transcription polymerase chain reaction analysis and the correlation between NPRL2 expression and clinicopathologic parameters. RNA expression patterns showed that the decreased NPRL2 expression was observed in 46.15% of the patients. Unaffected NPRL2 expression was detected in 23.07 of patients. There was not a significant correlation between NPRL2 expression and in a clinicopathological parameters. Our results suggest that the expression of NPRL2 may contribute to the progression of colon cancer however further studies are required to elucidated the role of NPRL2 in colon tumorigenesis

Factor V Leide mutation in cerebrovascular disease.

Several studies indicate a high prevalence of factor V Leiden mutation as the most frequent coagulation defect found in patients with venous thrombosis. The relationship between this mutation and cerebrovascular disease has not been established in adults. In this investigation, we studied 29 patients with ischemic stroke and 20 with intracerebral hemorrhage, all of whom were compared with 20 controls. A region of the factor V gene containing the Leiden mutation site was amplified with polymerase chain reaction and the presence of mutation was determined with restriction enzyme digestion. We found no evidence of an association between factor V Leiden mutation and ischemic stroke or intracerebral hemorrhage. There was no evidence of association in subgroup the analysis by age, smoking status, myocardial infarction, hypertension, diabetes mellitus, or coronary disease. Factor V Leiden mutation doesn't seem to be associated with a risk of cerebrovascular disease. PMID: 16015421 [PubMed - indexed for MEDLINE

ADP-ribosylation of human serum proteins promoted by endogenous NAD glycohydrolase activity.

Incubation of human serum samples with [adenine-14C]NAD resulted in a time- and dose-dependent incorporation of adenine moiety into CCI3COOH-precipitable material. Incorporated radioactivity was relatively resistant to neutral hydroxylamine, but was completely released by treatment with NaOH. An incorporation was observed also after preincubation of NAD with NAD glycohydrolase from pig brain. NAD glycohydrolase activity in serum samples was then shown spectroscopically in an assay coupled to alcohol oxidation. Thus, this reaction was implicated to be due to the binding of ADP-ribose, formed under the action of a soluble, endogenous NAD glycohydrolase activity, to serum proteins. Analysis by NaDodSO4/polyacrylamide gel electrophoresis (PAGE) and autoradiography indicated that a polypeptide of 97 kD, but also two further polypeptides of higher molecular weight and serum albumin, were labelled after incubation with radioactive NAD

Kolon Kanserli Hastalarda SFRP1 Geninin Araştırılması

Kolon kanseri bir dizi moleküler değişim sonucunda önce adenoma ardından karsinoma oluşumu ile ortaya çıkan bir kanserdir. Her bir tümörde görülen genetik değişimler farklılık gösterse de, hücre çoğalması, apoptoz ve DNA onarımında görev alan genleri etkileyen mutasyonlar normal mukozanın karsinomaya dönüşmesine neden olur. Salgılan beş glikoproteinden oluşan sFRPs “Salgılanan Frizzled ilişkili proteinler ” ailesi, doğrudan yada dolaylı birçok mekanizma aracılığıyla kanoniyal ve nonkanoniyal sinyali vererek Wnt’i antagonize eder. Normal gelişim sürecinde; hücre büyümesi, hareketliliği ve farklılaşması Wnt sinyali aracılığı ile düzenlenirken, yetişkin organizmalarda Wnt sinyali doku homeostazını düzenler. Wnt’nin Fz’ye bağlanması, ß-kateninin fosfat grubunu kaybetmesine ve bunun sonucunda da kalımlı hale gelmesine yol açar. Fosfat grubunu kaybeden ß-katenin çekirdeğe geçerek burada hedef genlerin yazılımını uyarmak üzere yazılım etmen ailesinin bir üyesi olan “T-hücre etmeni/lenfosit enhanser etmen ailesi (TCF/LEF)” üyeleriyle etkileşime girer. Tümör hücrelerinde, hücre büyümesi ve çoğalması ile apoptosis kaybına katkısı olan Wnt sinyal yolağı bozuklukları kolon kanserlerin %90’ında erken evrede görülür. Bundan dolayı Wnt sinyalinin negatif düzenleyicisi olan sFRP’nin tümör oluşumunda önemli olduğu ve ifadesindeki azalmanın insan kanserleriyle ilişkili olduğu düşünülmektedir. Proje kapsamında 56 kolorektal kanserli hastadan alınan 56 tümör ve bu dokulara komşu normal doku örneklerinde sFRP1 geninin promotor metillenmesi ve ifadesi analiz edildi. Çalışma sonucunda 56 tümör örneğinin 33 tanesinin sFRP1 geninin promotor bölgesinde yer alan CpG adacığının metillendiği saptandı. Geriye kalan örneklerin 21 tanesine promotor metillenmesinin tümör dokusunda normal dokuya göre azalmış olduğu görülürken 2 tanesinde metillenme açısından bir farklılık bulunamadı (Tablo 1). Elde edilen metillenme değerlerinin klinik parametrelerle ilişkili olup olmadığı Chi-kare istatistik programı ile analiz edildiğinde metillenmenin bu parametrelerden bağımsız olduğu anlaşıldı. Promotor metillenmesi gen ifadesinin kontrolünde işlev gören bir epigenetik kontrol mekanizması olduğundan metillenmenin gen ifadesini etkileyip etkilemediğini anlamak üzere aynı örneklerde qRT-PCR ile gen ifade analizleri yapıldı. Bu çalışmanın sonucunda da gen ifedesinin tümör örneklerinin %85’inde normal dokuya kıyasla azalmış olduğu saptandı (Tablo 1). Aynı şekilde gen ifade düzeyinin klinik parametrelerle ilişkisi istatistiksel olarak değerlendirildiğinde sadece evre ile ilşkili olabileceği gösterildi Ayrıca gen ifade düzeyinin promotor metillenmesi ile ilişkisi Wilcoxan Signed Rank testi ile analiz edildiğinde genin sessizleşmesinin doğrudan promotor metillenmesi ile ilişkili olduğu görüldü (Tablo 2).. Çalışmamızın sonucu sFRP1 geninin kolorektal kanser gelişimi ile ilşkili olduğunu gösterdiği gibi sFRP1’in epigenetik düzenlenme ile kontrol edildiğini göstermektedir. Artmış (%) Değişmemiş (%) Azalmış (%) Metillenme 59 3,5 37,5 İfade 15 0 85 Tablo 1: SFRP1 metillenme ve ifade yüzdeleri İfade (%) % Azalmış Artmış Toplam (%) P Azalmış 25 7,5 32,5 Metillenme Artmış 60 7,5 67,5 0,001 Toplam 85 15 Tablo 2: SFRP1 Geninin Promotor metillenmesinin İfade üzerine etkis

Molecular analysis of the p27/kip1 gene in breast cancer.

Genetic polymorphisms and mutations of the genes involved in tumorigenesis may determine individual susceptibility for cancer. The p27/Kip1 protein belongs to the family of cyclin-dependent kinase-inhibitory proteins, which are negative regulators of cell-cycle progression. Reduced protein levels of p27/Kip1 have been reported in numerous human cancers including breast cancer. METHODS AND RESULTS: p27 gene mutations and the codon 109 polymorphism were investigated in breast cancer patients by single strand conformation polymorphism analysis, PCR-restriction fragment length polymorphism analysis and DNA sequencing. Mutations were identified in 2 of 24 breast tumor samples. One G-->A transition resulting in a silent mutation and a single base deletion resulting in a nonsense mutation were detected in one patient. Another breast cancer sample harbored a T-->A transition at codon 159. An association between the codon 109 B allele and breast cancer was observed. CONCLUSION: Our study indicates that mutational alterations in the p27 gene are rare in human breast cancer. The codon 109 B allele is associated with high-grade tumors

. Thrombophilia and inflammatory bowel disease: does factor V mutation have a role

An increased tendency for thromboembolism is a well known problem of inflammatory bowel disease (IBD). Microvascular thrombosis has also been claimed as a pathogenic factor in IBD. Recently a point mutation in the gene coding factor V (FV Leiden) has been identified in various thromboembolic diseases, but the role in IBD is unknown. OBJECTIVE: To determine the frequency of FV Leiden in IBD patients and compare with a group of controls. METHODS: Sixty-three IBD patients [43 ulcerative colitis (UC) patients and 20 Crohn's disease (CD) patients] and 36 healthy controls were included in the study. Only one of the UC patients had a history of cerebral thromboembolism. The extracted DNA from frozen blood was subjected to polymerase chain reaction for the amplification of FV gene. The amplicons were hybridized both with the mutant and wild-type probes to detect FV mutation. Readings of optical density above 0.3 were considered as positive results. According to the patterns of ELISA, heterozygosity and homozygosity for normal and mutant alleles were determined. RESULTS: Eight (18%) of UC patients were heterozygous normal and one (2%) patient had homozygous mutation. Eight (45%) of the 20 CD patients had a heterozygous pattern and one (5%) had a homozygous pattern. In the control group four (11%) subjects showed a heterozygous genotype. FV Leiden was found to be statistically more frequent in CD patients (P < 0.005) (odds ratio 6.5, 95% confidence interval 1.3-18.), but not in the UC patients as compared with controls (P> 0.05). There was no significant correlation between FV Leiden presence and disease activity, gender or disease duration for both UC and CD. CONCLUSION: The results suggest that FV Leiden is more frequent in CD patients, but not in the UC patients as compared with controls. The high rate of factor V mutation in our CD patients suggests the need for further studies to confirm a relationship between this mutation and aetiology of the disease