Quantitative Ultrasound (QUS) for the Assessment of Bone Health

Osteoporosis is known as a silent disease because bone density slowly decreases with advancing age and without symptoms. The incidence of osteoporosis is increasing yearly worldwide. Measuring bone mineral density (BMD) using conventional bone densitometry (DXA) is practical in diagnosis of osteoporosis but the cost is high and cannot be implemented in community. However, quantitative ultrasound (QUS) is a modern technique to measure the bone density and also for the diagnosis of osteoporosis. It is comparatively easy, reliable, less costly, and a safe method compared to other techniques. QUS consists of two main parameters which are known as broadband ultrasound attenuation (BUA) and speed of sound(SOS). QUS can also predict fracture risk of BMD. QUS showed significantly associated with BMD, bone micro architecture and mechanical parameters for In vitro studies and in human studies, QUS were found to be associated with BMD. Hence, QUS is capable to be new technique for bone assessment.

Effects of Phytosterol Supplementation on Lipid Peroxidation Induced by Carbon Tetrachloride in a Rat Model

Phytosterols are plant sterols with a chemical structure similar to cholesterol. It has anti-cholesterol, anti-cancer and anti-oxidant properties which are probably mediated by suppression of lipid peroxidation. However, there are limited studies on the effects of phytosterols on lipid peroxidation. The aim of this study is to determine the effects of phytosterols on plasma and tissue malondialdehyde (MDA) of rats exposed to carbon tetrachloride. The rats were divided into four groups of normal control (NC), carbon tetrachloride (CCl4), phytosterol (P) and phytosterol+carbon tetrachloride (P+CCl4). The P and P+CCl4 groups were pretreated with subcutaneous phytosterol at 140 mg/kg once weekly for 5 weeks while the NC and CCl4 groups only received olive oil (vehicle). A single oral dose of carbon tetrachloride was then given to rats in the CCl4 and P+CCl4 groups to induce lipid peroxidation. After 24 hours, all the rats were sacrificed and the plasma and tissue MDA were measured. Our results showed carbon tetrachloride had caused significant elevations of the plasma and hepatic MDA of the CCl4 group compared to the NC group. Phytosterol pretreatment (P+CCl4 INTRODUCTION Phytosterols or plant sterols are a group of steroid alcohols, phytochemicals naturally occuring in plants. They have a chemical structure which is similar to cholesterol (Weihrauch & Gardner 1978) and exist in several forms in plants (Law 2000; Katan et al. 2003; Abumweis et al. 2007) including β-sitosterol, campesterol, stigmasterol and cycloartenol (Ostlund 2002). Phytosterols are natural compo-nents found in the human diet. It made up 0.1 to 0.5% w/w of vegetable oils or margerine (Kochlar 1983) and are also found in corn, wheat and rice. Phytosterol intake varies according to the type of diet taken. Europeans consume about 200-300 mg/day of phytosterol (Morton et al. 1995) while the vegetarian Japanese have a higher intake of phytosterol (Nair et al. 1984). group) were able to prevent the MDA elevations. Phytosterols treatments in normal rats (P group) were found to reduce the hepatic MDA level. The conclusion of this study was that phytosterols are effective suppressor of plasma and hepatic lipid peroxidation. They have potential as supplements to further reduce lipid peroxidation in healthy individuals.

Effects of Palm Tocotrienols on Oxidative Stress and Bone Strength in Ovariectomised Rats

Oxidative stress has been associated with postmenopausal osteoporosis which pre-disposes to risk of fracture. Palm tocotrienol is a potent antioxidant and has the poten-tial to be used for treatment of post-menopausal osteoporosis. The aim of the study is to determine if palm tocotrienol supplementation could alleviate oxidative stress in ovariectomised rat model and improve its bone strength. The rats were divided into four groups: (i) sham-operated group (SHAM) (ii) ovariectomised-control group (OVX) (iii) ovariectomised and given 60mg/kg α-tocopherol by oral gavage (OVX + ATF) (iv) ovariectomised and given 60mg/kg palm tocotrienols by oral gavage (OVX + PTT). After eight weeks of treatment, blood samples were taken to measure oxidative status (MDA, SOD and GPX) while the femurs were biomechanically tested for strength and resistance to fracture. Ovariectomy was shown to induce oxidative stress as shown by the raised MDA levels and reduced GPX activity. Palm tocotrienols seemed to offer protection against the ovariectomy-induced oxidative stress as shown by the suppression of MDA levels and raised GPX and SOD activities in the OVX+PTT group. In comparison, α-tocopherol was only able to raise the SOD but not as high as palm tocotrienols. The biomechanical tests have shown that ovariectomy has not af-fected the bone strength significantly after eight weeks. Palm tocotrienols supplemen-tation for eight weeks was effective in preventing oxidative stress in a post-meno-pausal rat.

The effects of repeatedly heated frying oil and high cholesterol diet on the bone in ovariectomised rats

The use of repeatedly heated frying oils and intake of high cholesterol diet have been linked to bone damage. The aim of this study is to determine the combined effects of taking repeatedly heated frying oils (palm or soy oil) and high cholesterol diet on the dynamic histomorphometric parameters of bone. Ovariectomised rats were used as animal model of post-menopausal osteoporosis. After six months of treatment, Double-labeled Surface (dLS/BS), Mineralising surface (MS/BS) and Bone Formation Rate (BFR/BS) of ovariectomised rats (OvxC) were significantly reduced compared to the normal control group. Additions of fresh or once-heated palm or soy oil into high cholesterol diet seem to have improved the dynamic parameters towards the normal control values. However, when these oils were repeatedly heated, the protective effects were lost and the dynamic parameters except MS/BS dropped back towards the ovariectomised-control values.