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"Siklofosfamid merupakan senyawa antineoplastik golongan pengalkilasi yang banyak digunakan untuk mengobati penyakit keganasan. Alkilasi yang terjadi pada posisi N7 basa guanin di kedua untai rantai DNA mengakibatkan kegagalan replikasi sel yang berguna untuk terapi kanker. Kesalahan posisi alkilasi, salah satunya pada posisi O6 basa guanin, ternyata dapat memberikan efek mutagenik dan bahkan karsinogenik, yang dapat memicu kanker sekunder. Oleh karena itu, addition product (adduct) yang terbentuk akibat alkilasi tersebut, yaitu O6-metilguanin, dapat menjadi penanda biologis terhadap risiko terbentuknya kanker sekunder. Pada penelitian ini, dilakukan identifikasi senyawa O6-metilguanin dalam darah pasien kanker yang mendapatkan siklofosfamid dalam regimen kemoterapi selama minimal 4 siklus. Sampel yang digunakan adalah DNA yang diisolasi dari darah pasien kanker. Isolat DNA kemudian dihidrolisis dan dianalisis menggunakan metode Kromatografi Cair Kinerja Tinggi penukar kation kuat dengan fase gerak amonium format 30 mM pH 3,95 - metanol (94:6), suhu kolom 30°C, laju alir 1,2 ml/menit, dengan sistem deteksi fluoresensi menggunakan panjang gelombang eksitasi 300 nm dan emisi 370 nm. Penentuan O6-metilguanin dalam sampel dilakukan dengan membandingkan data waktu retensi sampel dengan standar, yaitu menit ke 7,600 dengan batas deteksi sebesar 20,74 ng/ml (setara dengan 128813,52 μV/s). Sampling dilakukan terhadap 27 pasien, tetapi hanya 17 sampel DNA pasien yang dapat teranalisis dan O6-metilguanin terdeteksi dalam 1 sampel DNA pasien.

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Cyclophosphamide is one of alkylating agent which widely use in chemotherapy. Alkylation occurred in N7-guanine position in both DNA strand causes the cancer cell failed to replicate, hence gives the cytotoxic effects which is beneficial for the cancer therapy. Contrary, if the alkylation occurres in O6-guanine position, the drug gives mutagenic and carcinogenic properties which vulnerably leads to secondary cancer. Therefore, detection of the adduct formed, O6-methylguanine, is able to become a biomarker for the risk of secondary cancer?s development. In this research, O6-methylguanine was identified from patient which had been receiving cyclophosphamid in their chemotherapy for minimum 4 cycles. Patient?s DNA which isolated from their blood, were being hydrolized and identified. Analytical method which use in this research was High Performance Liquid Chromatography with strong cation exchange column, mobile phase consisted of 30 mM ammonium formate pH 3,95-methanol (94:6), flow rate 1,2 ml/min, column temperature 30°C and detected at excitation wavelength 300 nm and emission wavelength 370 nm. Standart of O6-methylguanine in samples was conducted with comparing retention time data from sample and standar, which was eluted in 7.600 minute and with limit of detection as 20,74 ng/ml (equals to 128813,52 μV/s). Sampling was conducted in 27 patients but only 17 patient?s DNA samples were able to be analyzed and O6-methylguanine was detected in 1 sample."

"Penelitian ini dilakukan untuk menganalisis pembentukan DNA Adduct 8-OHdG akibat kerusakan oksidatif DNA yang disebabkan oleh paparan akrilamida (1 mg/kg BB) dan Cu (II) (10 mg/kg BB). Studi in vivo dilakukan dengan menggunakan kelompok tikus (Rattus norvegicus) galur Sprague Dawley yang diberi paparan selama 28 hari dan dilakukan pengambilan sampel urin setiap 7 hari. Studi in vitro dilakukan dengan mereaksikan 2-„deoksiguanosin pH 7,4 dengan akrilamida, Cu (II), H2O2 melalui reaksi Fenton-like pada suhu 37 °C. Analisis 8-OHdG dilakukan dengan instrumentasi LC-MS/MS ionisasi positif, fasa terbalik, dengan gradien elusi campuran ammonium asetat 20mM dan asetonitril. Hasil studi in vivo menunjukkan bahwa paparan akrilamida, Cu, dan gabungan akrilamida + Cu (II) mengakibatkan adanya kerusakan DNA yang dapat menimbulkan risiko kanker. Kelompok paparan gabungan akrilamida + Cu (II) menunjukkan kadar yang paling tinggi, hal ini menunjukkan adanya kesinergisan antara akrilamida dan Cu (II) pada pembentukan kadar 8-OHdG. Pengujian kadar 8-OHdG secara berkala menunjukkan kadar 8-OHdG yang semakin meningkat seiring dengan lamanya waktu paparan. Hasil studi in vitro menunjukkan bahwa akrilamida tidak menginduksi pembentukan 8-OHdG secara langsung, melainkan perlu adanya proses metabolisme terlebih dahulu.

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This study was conducted to analyze the formation of 8-OHdG DNA Adduct due to oxidative DNA damage caused by exposure to acrylamide (1 mg / kg BB) and Cu (II) (10 mg / kg BW). In vivo studies were carried out using a group of Sprague Dawley rats (Rattus norvegicus) that were exposed for 28 days of exposure and urine samples were taken every 7 days. In vitro studies were carried out by reacting 2-oksdeoxiguanosine pH 7.4 with acrylamide, Cu (II), H2O2 through Fenton-like reaction at 37 ° C. The 8-OHdG analysis was performed with positive ionization LC-MS / MS instrumentation, reversed phase system, with a mixture of elution gradient of ammonium acetate 20mM and acetonitrile. The results of in vivo studies showed that acrylamide, Cu, and acrylamide combined Cu (II) exposure caused DNA damage that could cause cancer risk. The exposure group of acrylamide combined Cu (II) combined showed the highest levels, this indicates a synergy between acrylamide and Cu (II) in the formation of 8-OHdG levels. Periodic analysis of 8-OHdG levels shows that 8-OHdG levels are increasing along with the length of time of exposure. In vitro testing shows that acrylamide does not directly induce the formation of 8-OHdG, but rather requires a metabolic process first."