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Öğe Bitkilerde RNA interferans(Refik Saydam Hıfzıssıhha Merkezi Başkanlığı, 2015) Aras, Sümer; Soydam Aydın, Semra; Fazlıoğlu, Aslı; Cansaran Duman, Demet; Büyük, İlker; Derici, Mehmet KürşatR RNA interferans (RNAi) mekanizması, hücreye giren çift zincirli RNA’nın (dsRNA) komplementeri olan mRNA zincirinin degradasyonuna yol açması ile sonuçlanan transkripsiyon sonrası gen susturma (post-transcriptional gene silencing), ya da gen ifadesinin düzenlenmesi olarak tanımlanır. RNAi mekanizması sırasında, hedef mRNA’ya komplementer dizi, 500 kDa ağırlığında ve nükleaz aktiviteli bir RNA-multi protein kompleksi olan RISC faktörü aracılığı ile mRNA’nın anlamlı dizisine bağlanır ve gen susturulma mekanizması bu RISC faktörü aracılığı ile kontrol edilir. Gen susturulması mRNA’nın RISC faktöründe bulunan ‘Argounate’ proteinle etkileşime girmesi ve ‘Dicer’ enzimi tarafından tanınıp kesilmesi ile gerçekleşir. Bu mekanizma, genomun virüs kalıtım materyali ve transpozonlar gibi hareketli genetik elementlerin istilasından korunmasını sağlamak amacıyla gerçekleşen doğal bir işlemdir. RNAi mekanizması, ökaryot organizmalarda iki tür molekül tarafından gerçekleştirilir. Bu moleküller 22 nükleotid uzunluğunda miRNA (micro RNA) ve 21- 23 nükleotid uzunluğunda, çift zincirli siRNA (small interfering RNA) molekülleridir. Son yıllarda bilim dünyasının önde gelen konuları arasında yer alan RNAi araştırmaları ile çeşitli organizmalarda genlerin işlevlerini inceleme, işlevlerini bilmediğimiz genlerin fonksiyonlarını belirleme, konak patojen ilişkisi, üreme, programlanmış hücre ölümü, tümör oluşumu gibi birçok alanda bilgi sahibi olunmuştur. Ayrıca; bitkilerde kodlanmayan RNA’ların doku farklılaşması ve gelişiminin kontrolü, sinyal iletimi, fitohormonlarla etkileşim, abiyotik (kuraklık, tuzluluk vb.) ve biyotik (patojenler vb.) stres gibi çevresel etmenlere verilen cevaplarda rol oynadığı görülmüştür. Bu derleme çalışmasında RNAi mekanizmasının temelleri ve bitkilerde RNAi kullanımı açıklanmaya çalışılacaktır.Öğe Global Research Trends On Vaginismus And Female Sexual Dysfunction In 1980-2019: A Scientometric Analysis(2020) Yıldırım, Engin; Derici, Mehmet Kürşat; Türkler, CanObjective: Physiological and psychological conditions can cause female sexual dysfunction (FSD). It is called vaginismus when sexual dysfunction occurs with vaginal cramps and spasms. The aim of our research is to present the research topics and trends about FSD and vaginismus to the reader in a global context Material and Methods: We used the terms ‘female sexual dysfunction’ and ‘vaginismus’ as keywords and we determined the articles indexed in the Web of Science database. We included all the articles in the database between 1980 and 2019. Documents of 2020 were excluded from this study. Gunnmap free open web-based application was used to visualize global research productivity. Vos-viewer 2019 program was used to determine the scientific relevance of the data. Results: We reached 2212 documents in total, 95.6 % of these articles were written in English, and 64.4% of the documents were original articles. Articles about vaginismus and FSD increased in the 1995s, the most productive year was 2019. The most productive country in genital cosmetics and aesthetics was the United States (USA), the most productive university was The University of British Columbia. The most productive writer was Goldstein I. Conclusion: Studies on vaginismus and FSD have increased over the past decade, and and non-invasive psychiatric interventions appear to be popular. Our analysis is an identity provider for articles covering vaginismus and FSD.Öğe Importance of NK Cells in Cellular and Humoral Responses Triggered by Pneumococcus Vaccination(KARGER, 2023) Gazi, Umut; Tosun, Özgür; Derici, Mehmet Kürşat; Karasartova, Djursun; Güreser, Ayşe Semra; Taylan Özkan, Hikmet AyşegülIntroduction: Despite the success of vaccination in reducing overall rate of pneumococcal pneumonia, Streptococcus pneumoniae is still held responsible for high mortality and modality rates worldwide. Our study aimed to investigate the potential role played by NK cells in immune response generated by pneumococcal vaccination, which could contribute to the development of more effective vaccines. Methods: The study included mice with and without NK cell depletion which were immunized with pneumococcus polysaccharide-conjugated vaccine followed by pneumococcus polysaccharide vaccine (PPV). Serum samples and splenocytes were collected from mice sacrificed 4 weeks after the last PPV dose. Serum samples were used for antibody level quantification by ELISA assay, while splenocytes were treated with PPV in vitro before monitoring CD4+ T-cell subsets (TH1, TH2, and TH17) and cytokine (IFN-?, IL-4, and IL-17) secretion levels by flow cytometry and ELISA analysis, respectively. Results: Results demonstrated reduced pneumococcal IgG and TH1 cell levels due to NK cell depletion. Nevertheless, in contrast to these observations, IFN-? secretion levels after in vitro PPV-23 treatment of splenocytes did not exhibit any statistically significant difference between the two mice groups. Conclusions: The data indicate a positive contribution of NK cells to both T-cell and B-cell responses triggered against pneumococcal vaccination. Further studies are required to confirm our data and investigate the potential benefit of NK cell targeting in promoting vaccine efficacy, especially in the elderly population who continues to be affected significantly by pneumococcal pneumonia.Öğe Is the Concentration of Cadmium, Lead, Mercury, and Selenium Related to Preterm Birth?(Humana Press Inc., 2019) Yıldırım, Engin; Derici, Mehmet Kürşat; Demir, Emre; Apaydın, Hakan; Koçak, Özgür; Kan, Özgür; Görkem, ÜmitEnvironmental pollution and exposure of people to heavy metals cause many bad obstetric outcomes. Our aim is to demonstrate the role of cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) in preterm labor etiology with a case-control study. In this study, between November 2017 and April 2018, preterm delivery mothers and term delivery mothers were compared in Çorum, Turkey. All deliveries were performed with cesarean sections and there were 30 mothers in the control group and 20 in the study group. The maternal blood, maternal urine, umbilical cord blood, and heavy metal levels in the amnion fluid in both groups were studied. Graphite furnace atomic absorption spectrometry was used to determine the blood concentration of Cd, Pb, Hg, and Se. We found lower levels of selenium in blood and urine of preterm delivery mothers and umbilical cord and amnion fluids of preterm infants (p < 0.01). We found a statistically significant positive correlation at selenium levels between mother’s blood and umbilical cord blood (r (50) = 0.896, p < 0.001) and between maternal urine and amniotic fluid (r (50) = 0.841, p < 0.001). We have not found a similar correlation between mother and fetus of other metals (p > 0.05). We found that selenium levels were lower in mothers who were preterm birth in the light of the data in our study. We could not determine the positive or negative correlation of Cd, Pb, and Hg levels in blood, urine, and amniotic fluid samples with preterm birth. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.Öğe Is there a relationship between serum kisspeptin levels and endometrial polyps in women with premenopausal status(2019) Yıldırım, Engin; Derici, Mehmet Kürşat; Şimşek, Ömer Yavuz; Demir, EmreAim: Endometrial polyps are frequently associated with abnormal uterine bleeding. The kispeptin family is one of the peptides that play a role in reproductive functions and whose expression varies in various uterine pathologies. The aim of the study was to determine the relationship between serum Kisspeptin levels and endometrial polyps in women with premenopausal status. Material and Methods: The blood was collected prior to endometrial sampling from women admitted to the hospital due to abnormal uterine bleeding. According to the pathology results, patients were identified as polyp group (n=38) (endometrial polyps) and control group (n=50) (normal endometrial findings). Kisspeptin-54 levels were determined by ELISA method from serum obtained from venous blood. Results: There were no difference was found between the patients’ age, body mass index, gravida, para, abortus and the number of living children were compared (p>0.05). There was no statistically significant difference between the groups in terms of follicle stimulating hormone, luteinizing hormone and thyroid stimulating hormone values (p>0.05). Plasma kisspeptin (1.84±0.93 ng/dL and 1.32±0.47 ng/dL, p= 0.008) and estradiol (90.34±13.02 pg/mL and 81.75±12.36 pg/mL, p=0.002) levels were significantly higher in the polyp group than in the control group. After the Receiver Operating Characteristic (ROC) analysis the area under the curve (AUC) was 1.26 (p= 0.08), (95% CI, 0.550-0.782). The sensitivity value was 0.684 (0.512-0.819), the specificity was 0.620 (0.471- 0.750). Conclusion: The serum Kisspeptin-54 and estradiol levels were found higher in patients with endometrial polyps.Öğe Nitrik oksitin kanser gelişimi ve metastaz üzerine etkileri(Refik Saydam National Public Health Agency (RSNPHA), 2017) Derici, Mehmet Kürşat; Demirel Yılmaz, EmineNitrik oksit (NO), birçok hücre içi ya da hücreler arası uyarı yolağında görev alan benzersiz bir moleküldür. Farklı kanser hücrelerinde ve dokularında saptanan değişik NO düzeylerinin, farklı düzenleyici etkiler ortaya koyduğu birçok çalışmada gösterilmiştir. Yapısal olarak üretilen NO, kanser hücresi fenotipinin ortaya konmasında önemli rol üstlenmektedir. Bu; kanserin çevre dokulara penetre olmasını, uzak bölgelere yayılmasını ve gelişimi için gerekli olan kaynaklara ulaşabilmesi sağlayacak, en yüksek kan akımını alacağı damarlanma işlevini; kapsamaktadır. Genel olarak, dokuda düşük derişimlerde sentezlenen NO’in etkileri pro-kanseröz olarak değerlendirilebilir. Çok yüksek derişimlerde ise NO, apopitozu, nekrozu uyararak veya anjiyojenezi inhibe ederek, güçlü bir anti-kanser madde olarak görev yapmaktadır. Öte yandan, NO düzeylerindeki artışın, metastaz basamakları üzerine olan etkileri sebebiyle kanserin farklı lokalizasyonlarda büyümesini ve ilerleyişini arttırabildiği ortaya konmuştur. Metastazda NO’in oynadığı rol, hücre tipi, NO derişimi, katılan organlar veya NO’in kanseral sürece katıldığı dönem gibi, farklı faktörlerden etkilenmektedir. NO’in bu çok yönlü ve farklı etkileri, kanserin büyümesini yavaşlatmak ve kemoterapi/radyoterapi etkinliğini arttırmak amacıyla, kanserin birçok preklinik modellerinde kullanılmaktadır. Bu yaklaşımlar yeni anti-kanser stratejileri olarak ön görülmektedir.Öğe Skin-homing T-cell responses associated with Demodex infestation and rosacea(Wiley, 2019) Gazi, Umut; Güreser, Ayşe Semra; Öztekin, Aynure; Karasartova, Djursun; Koşar Acar, Nezahat; Derici, Mehmet Kürşat; Taylan Özkan, Hikmet AyşegülAims Our aim was to investigate the skin-homing T-cell immune responses triggered in patients with Demodex infestation and/or rosacea. Methods Collected whole blood samples were divided into four groups: control subjects; nonrosacea patients with Demodex infestation (Demodex group); papulopustular rosacea (PPR) patients without Demodex infestation (Rosacea group); and PPR patients with Demodex infestation (Rosacea/Demodex group). Following ex vivo activation, skin-homing CLA+CD4+ T-cell subset levels were monitored by flow cytometry. Results When compared with control subjects, among skin-homing CD4+ T-cell subsets analysed, Demodex patients had higher T(H)9 and T-reg cell levels; Rosacea subjects displayed elevated T(H)1 cell levels; and Rosacea/Demodex patients exhibited increased frequencies of T(H)9 and T(H)22 cells. In contrast to Rosacea subjects, Rosacea/Demodex group members displayed higher T(H)2 cell levels; and when compared with Demodex groups, they had higher T(H)1 and T(H)2 but lower T-reg cell levels. Demodex group members also exhibited higher T-reg but lower T(H)1 and T(H)22 levels than Rosacea/Demodex group subjects. Conclusions The skin-homing T-cell responses associated with Demodex infestation and rosacea formation seem to influence each other. The present as well as future studies could contribute to the development of effective treatment strategies for demodicosis and rosacea.Öğe The Effect of Heavy Metals on Miscarriage(2019) Yıldırım, Engin; Derici, Mehmet KürşatObjective: In a world where industrial pollution is increasing day by day, heavy metals are one of the important factors threatening human health. The rates of pregnancy loss and subfertility are continuously increasing. This study aims to explain the effects of lead (Pb), cadmium (Cd), and mercury (Hg) levels on the etiology of abortions. Material and Methods: The study was designed as a case-control study with two groups: healthy volunteers (n=20) and miscarriage (n=29) group. The pregnant women with similar demographic characteristics were divided into two groups and peripheral venous blood samples of the study subjects were collected. Atomic absorption spectrophotometer was used to examine the blood samples and the levels of heavy metal. Results: While the Pb level was found to be higher in the miscarriage group (p=0.038), there was no statistical difference between Cd and Hg levels (p>0.005) in the two groups. On comparing the laboratory values of pregnant women in the control and miscarriage groups, blood progesterone values were observed to be lower in the miscarriage group (p<0.001). Conclusion: This study indicates that heavy metals, even below the toxic dose limits, can cause miscarriage. Higher blood Pb levels were found in the miscarriage group while Hg and Cd levels were not different between the two groups. This research points out that the high levels of lead may have an effect on pregnancy loss.Öğe The effect of splenectomy on the levels of PCV-13-induced memory B- and T cells(Blackwell Publishing Ltd, 2018) Gazi, Umut; Karasartova, Djursun; Şahiner, İbrahim Tayfun; Güreser, Ayşe Semra; Tosun, Özgür; Derici, Mehmet Kürşat; Dolapçı, Mete; Taylan Özkan, Hikmet AyşegülAim: Splenectomised patients are associated with lifelong risk of fatal overwhelming post-splenectomy infection (OPSI), which is mostly caused by Streptococcus pneumoniae. Today OPSI cases can still be reported even in patients with appropriate vaccination. In our study, the levels of vaccine-specific memory B- and T cells were compared between control and splenectomised patients to enlighten the underlying reason. Materials and Methods: Five healthy and 14 post-traumatic splenectomised individuals were vaccinated with 13-valent pneumococcal conjugate vaccine (PCV-13) followed by 23-valent pneumococcal polysaccharide vaccine (PPV-23). The levels of memory B- and T cells were compared by ELISPOT analysis. Results: Splenectomised patients generated reduced levels of memory IgG B cells in response to PCV-13 vaccination, while the memory IFN-? T-cell levels were undetectable in asplenic patients. This was despite the detection of vaccine-induced memory T-cell levels in control patients, which were analysed simultaneously following the same experimental protocol. Conclusion: Our results suggest that spleen is important, but not essential, for survival and/or generation of memory IgG B cells. In contrast, it seems to be indispensable for PCV-13-specific memory TH1-cell levels. Studies enhancing the levels of vaccine-induced memory cells and further enlightening the immune responses in asplenic individuals are required to develop more effective vaccination strategies against OPSI. © 2018 John Wiley & Sons LtdÖğe Usnic acid causes apoptotic-like death in Leishmania major, L. infantum and L. tropica(Springer Verlag, 2018) Derici, Mehmet Kürşat; Cansaran Duman, Demet; Taylan Özkan, Hikmet AyşegülLeishmaniasis, a deadly parasitic infection, threatens many people worldwide. Since the high cost, toxicity, and resistance are drawbacks of current treatment options, it is necessary to find safer and more effective new antileishmanial drugs. The aim of this study was to determine the antileishmanial activity of usnic acid and its apoptotic mechanism on Leishmania spp. promastigotes. The antileishmanial activity was evaluated by MTT assay and apoptosis-related gene expression was investigated by qRT-PCR. Usnic acid was to be effective against Leishmania major, L. infantum, and L. tropica promastigotes at IC 50 = 10.76 µg/ml, 13.34 µg/ml, and 21.06 µg/ml, respectively. We also demonstrated a novel mechanism by which usnic acid inhibited proliferation and caused apoptosis; usnic acid upregulated p53, Bax, Casp-3, and Casp-9 gene expression and downregulated the level of Bcl-2 gene expression. Accordingly, the expression level of the P53 gene increased in L. major, L. infantum and L. tropica by 14.4-, 11.8-, and 9.5-fold, respectively, and in contrast, the Bcl-2 gene expression decreased in all three leishmaniasis by 0.8-, 0.8-, and 0.7-fold, respectively. The present study, therefore, revealed that usnic acid played a critical role in the usnic acid-induced apoptotic process in Leishmania species. Usnic acid is easily accessible and an inexpensive agent, and can be considered as an alternative therapeutic agent for Leishmania infections subject to further tests in animal models. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
