Judul: IPB (Bogor Agricultural University)
Abstrak: The use of Percoll gradients for Leydig cells isolation has been reported to influence cell toxicity and reduce the viability and the amount of living cells after culture. To dissolve this problem, study has been carried out used non toxic Nycodenz gradient to isolated and purified the Leydig cells. The use of Nycodenz gradient for the isolation and purification of Leydig cells has not been done by other researchers. To obtain the optimum condition of Leydig cells production, growth factor is required as supporting factors for development of growing cells. Therefore, hCG and ITS has been used in this study. Leydig cells conditioned medium (LCM) contained bioactive materials such as testosterone and growth factors. The Leydig cells conditioned medium as culture medium for bone marrow mesenchymal stem cells will be used to determine its influence to differentiation of cells. The phase of this study included: 1. Isolation and purification of Leydig cells using Nycodenz gradient : (I) with 3 column ( 5 % , 10 % , 15 % ) and ( II ) with 5 columns ( 4 % , 8 % , 10 % , 12 % , 15 % ) and Percoll gradient ( 21 % , 26 % , 34 % , 40 % , 60 % ) as a control . 2. In vitro culture of the best result from cell purification was cultured with the addition of hormones and growth factors : (1) DMEM+NBCS 10% as control, (2) DMEM + NBCS + 2.5 IU/ml hCG , (3) DMEM + NBCS+ 5 ug / ml insulin, 10 ug/ml transferrin, selenium 5 ug/ml (ITS ) and (4) DMEM +NBCS + hCG+ITS . 3 . The concentration of testosteron and protein analyzed from Leydig cells conditioned medium has been used for culturing bone marrow mesenchymal stem cells. The result of first phase study was Nycodenz gradient have the same purity and viability compared with Percoll gradient. After 3 days cultured, in Nycodenz gradient the concentration and viability of Leydig cells more higher than Percoll gradient. The combination of hCG and ITS in DMEM produced Leydig cell proliferation (90.64%) higher compared with hCG (86.99%), ITS (88.35%) and control (86.82%). Proliferation rate (population doubling time, PDT) from primary culture using combination of hCG and ITS showed the fastest (0.88 day) compared with ITS (0.97 day), hCG (1.02 day) and control (1.03 day). The same result of Leydig cells proliferation rate has also showed in first and second cell lines. Testosterone consentration analyzed was the highest (5.25 ng/ml) in DMEM combination with hCG and ITS compared with other treatments (hCG 5.06 ng/ml; ITS 3.19 ng/ml and control 2.46 ng/ml). Differentiation to became Leydig cells from bone marrow mesenchymal stem cells has been known from positive reaction to 3β-HSD staining. Added of hCG to Leydig cells conditioned medium was able to increased the number of Leydig cells to 71.9%. It was also showed that concentration of testosterone has been increased (0.93 ng/ml and 10.22 ng/ml) in the culture medium. The combination of hCG and ITS in DMEM had testosterone (0.71 ng/ml) and protein
Keyword: Leydig cells, rat, Nycodenz, testosterone, mesenchymal stem cells, bone marrow, conditioned medium, transdiferentiation

Judul: Respon Sel Leydig Dari Mencit Neonatal Terhadap Hcg Selama Kultur In Vitro.
Abstrak: Sel Leydig merupakan sel penghasil hormon testosteron pada hewan jantan. Berdasarkan tingkat kematangan, populasinya terbagi menjadi sel Leydig fetal dan sel Leydig dewasa. Hormon human chorionic gonadotropin (hCG) adalah salah satu faktor yang memengaruhi proliferasi dan diferensiasi pada sel Leydig dewasa, tetapi belum diketahui pengaruhnya pada sel Leydig fetal. Penelitian ini bertujuan untuk menjajaki respon sel Leydig fetal terhadap penambahan hCG pada kultur in vitro dengan menggunakan sel Leydig yang diisolasi dari mencit neonatal. Sel Leydig diisolasi dari mencit neonatal umur tiga hari, dikultur in vitro selama enam hari, dan diberi perlakuan dengan dan tanpa penambahan hCG. Data yang dievaluasi berupa tingkat proliferasi (population doubling time, PDT) dan jumlah sel yang mengekspresikan keberadaan enzim 3β-HSD. Hasil penelitian menunjukkan bahwa penambahan hCG pada kultur in vitro sel Leydig dewasa meningkatkan proliferasi sel, sebaliknya pada sel Leydig fetal menurunkan proliferasi sel. Penambahan hCG tidak memengaruhi persentase jumlah sel Leydig dari mencit neonatal yang mengekspresikan enzim 3β-HSD. Dapat disimpulkan bahwa sel Leydig fetal dari mencit neonatal memiliki respon yang berbeda dengan sel Leydig dewasa terhadap penambahan hCG secara in vitro.
Keyword: hCG, kultur in vitro, mencit neonatal, proliferasi, sel Leydig

Judul: Mencari Aproksimasi Akar-Akar Polinomial Kompleks Dengan Algoritma Weyl
Abstrak: Mencari akarMakar polinomial dengan menggunakan algoritma Weyt. Algoritma WeyJ merupakan algoritma rekursif yang proses kerjanya dapat diana10gkan dengan algoritma Bisection. Karena algoritma Weyl bergerak dalam bidang kompleks maka memerlukan nilai awal hempa bujur sangkar. Dalam proses penyempitan bujur sangkar tersebut algoritma Weyl memerlukan algorittna Turan untuk menentukan jarak antara suatu titik dengan akar polinomial yang terdekat dengan titik tersebut. Karena apabiJa jarak tersebut temyata lebih hesar dari Yl panjang diagonal bujur sangkar yang diamati maka bujur sangkar tersebut tidak memuat satu pun akar polinomial. Untuk seJanjutnya bujur sangkar tersebut diabaikan. Sebaliknya apabila jarak yang diperoleh lebih keeil dari \6 panjang diagonal bujur sangkar yang diamati, maka bujur sangkar tersebut yang akan diperkeciL
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