Browsing by Author "Darmawan, Hardi"

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    Effect of age and sex on the association between lipid profile and obesity among telecomunication workers in Palembang.
    (2007-10) Darmawan, Hardi; Irfanuddin, Irfanuddin
    The study objective is to examine the effects of age and sex on the association between various obesity parameters and lipid profile. The measurements of whole body obesity (body fat, body fat % and BMI), abdominal obesity (waist to hip ratio, waist to thigh ratio and waist circumference) and lipid profile (HDL, LDL, VLDL, total cholesterol and triglyceride) were performed on 112 telecom workers in Palembang (84 men and 28 women, age 25, 35, 45, and 55 years). All lipid parameters results depend on sex and age of subjects. The association between obesity assessments and HDL or LDL was independent of sex and age of subjects, whereas the association between obesity assessments and total cholesterol, VLDL and triglyceride is dependent on sex and age of subjects. Abdominal obesity has greater effect on VLDL and triglyceride levels than on other lipid parameters. Whole body obesity has equal effects on all lipid parameters. When comparing results of male and female subjects, obesity measurements and lipid profile association is stronger in male subjects of almost all age groups. The exception is a stronger association between abdominal obesity and VLDL or triglyceride levels in 45 years old female subjects. Obesity measurements and VLDL or triglyceride level association is independent of age, whereas obesity and total cholesterol association is stronger in younger subjects.
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    Production of ROS and its effects on mitochondrial and nuclear DNA, human spermatozoa, and sperm function.
    (2007-04) Darmawan, Hardi
    Over the past few decades many researchers studying the causes of male infertility have recently focused on the role played by reactive oxygen species (ROS) – highly reactive oxidizing agents belonging to the class of free radicals. If ROS levels rise, oxidative stress (OS) occurs, which results in oxygen and oxygen derived oxidants, and in turn increases the rates of cellular damage. In human, ROS are produced by a variety of semen components, and antioxidants in the seminal fluid keep their level balance. Small amounts of ROS help spermatozoa acquire their necessary fertilizing capabilities. Many researches showed that ROS attack DNA integrity in the sperm nucleus by causing base modification, DNA strand breaks, and chromatin cross linking. The DNA damage induced excessive levels of ROS and might accelerate the process of germ cell apoptosis leading to a decline in sperm counts associated with male infertility. This paper will review the molecular (cellular) origins of ROS in human semen, how ROS damage sperm nuclear DNA, and how such DNA damage contributes to male infertility. Increased ROS production by spermatozoa is associated with a decreased mitochondrial membrane potential (MMP), which is an important indicator of functional integrity of the spermatozoa. Germ cell apoptosis is essential for normal spermatogenesis and its dysregulation may lead to male infertility. Thus, understanding the causes and mechanisms of germ cell apoptosis is of major importance in preventing male reproductive problems. Levels of apoptosis in mature spermatozoa that were significantly correlated with levels of seminal ROS determined by chemiluminescence assay indicate the linkage between ROS and male fertility problems.