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1.  Amelioration of azoxymethane induced-carcinogenesis by reducing oxidative stress in rat colon by natural extracts 
Background
Azoxymethane (AOM) is a potent carcinogenic agent commonly used to induce colon cancer in rats; the cytotoxicity of AOM is considered to mediate oxidative stress. This study investigated the chemopreventive effect of three natural extracts [pomegranate peel extract (PomPE), papaya peel extract (PapPE) and seaweed extract (SE)] against AOM-induced oxidative stress and carcinogenesis in rat colon.
Methods
Eighty Sprague–Dawley rats (aged 4 weeks) were randomly divided into 8 groups (10 rats/group). Control group was fed a basal diet; AOM-treated group was fed a basal diet and received AOM intraperitonial injections for two weeks at a dose of 15 mg/kg bodyweight, whereas the other six groups were received oral supplementation of PomPE, PapPE or SE, in the presence or absence of AOM injection. All animals were continuously fed ad-libitum until aged 16 weeks, then all rats were sacrificed and the colon tissues were examined microscopically for pathological changes and aberrant crypt foci (ACF) development, genotoxicity (induced micronuclei (MN) cells enumeration), and glutathione and lipid peroxidation.
Results
Our results showed that AOM-induced ACF development and pathological changes in the colonic mucosal tissues, increased bone marrow MN cells and oxidative stress (glutathione depletion, lipid peroxidation) in rat colonic cells. The concomitant treatment of AOM with PomPE, PapPE or SE significantly ameliorated the cytotoxic effects of AOM.
Conclusions
The results of this study provide in-vivo evidence that PomPE, PapPE and SE reduced the AOM-induced colon cancer in rats, through their potent anti-oxidant activities.
doi:10.1186/1472-6882-14-60
PMCID: PMC3932801  PMID: 24533833
Azoxymethane; Oxidative stress; Colon cancer
2.  Lifestyle Habits 
Objectives:
This study aimed to investigate the lifestyle habits—physical activity (PA), eating habits (EH), and sleep duration (SD)—of Omani adolescents, and to examine gender differences in such variables.
Methods:
802 Omani adolescents (442 females and 360 males), aged 15–18 years were randomly recruited. Anthropometric indices, PA level, and EH and SD were evaluated by the Arab Teenage Lifestyle questionnaire. A semi-quantitative food frequency questionnaire for dietary assessment was also administered.
Results:
The results showed that although the study subjects had a sedentary lifestyle (lack of PA, average of 6.7 hours sleep, and consumption of high calorie foods), they maintained a normal body mass (less than 25 Kg/m2). Males were more than twice as active as females. With respect to EH, there were few gender differences, except in dairy and meat consumption where 62.5% and 55.5% of males consumed more than 3 servings, respectively, compared to 18.78 % and 35.2% of females, respectively. In addition, waist/height ratio, height, reasons for being active, energy drinks, potato consumption, eating sweets, vigorous PA and breakfast EHs were statistically significant independent predictors for BMI, P <0.05 for both males and females.
Conclusion:
This study revealed a high prevalence of sedentary behaviors and a low level of physical activity, especially among females. Unhealthy dietary habits were also widely found among both genders. There is an urgent need for more research as well as a national policy promoting active living and healthy eating and discouraging sedentary behaviour among Omani adolescents.
PMCID: PMC3836639  PMID: 24273660
Adolescent; Oman; Lifestyle; Physical Activity; Dietary Habits; Index, Body Mass; Sleep; Habits
3.  Nutritional Practices of Athletes in Oman: A Descriptive Study 
Oman Medical Journal  2013;28(5):360-364.
Objective
Adequate dietary intake is crucial for optimum training and performance of athletes. There is almost no available information related to dietary practices among Omani athletes, especially during the competition. This study aimed to assess the nutritional practices (nutritional knowledge, eating habits and daily nutrients intake) among Omani male handball athletes in Muscat city, Oman.
Methods
This is a cross sectional study including 35 male handball athletes involved in serious training for no less than three years. Data collection was done through personal interviews using a study questionnaire which enlisted questions relating to socio-demographic information, anthropometric measurements and nutritional practices. All the study participants declared no intake of anabolic steroids.
Results
The mean age of the study participants was 27 ± 3 years. Their anthropometric assessment revealed that their mean height was 166 ± 12 cm, mean weight was 75 ± 10 kg, and body mass index was 27 ± 3. Nutritional knowledge analysis revealed that 80% had no nutritional supervision by a nutritionist/dietitian. Their knowledge of nutritional requirements was only 23% correct for total energy intake, 63% for protein intake, 46% for carbohydrate intake, 11% for fat intake and 83% for water intake. Eating habits indicated that 55% had <3 meals/day, 51% had lunch as the principal meal, 51% always added extra salt to their food, 28% took protein supplements on a daily basis, and 51% used pre-competition glycogen load diet. However, none consumed vitamins or mineral supplements. The mean daily caloric intake was 3674 ± 265 kcal/day, which was roughly comprised of 596 ± 66 g carbohydrates, 147 ± 28 g of protein and 78 ± 20 g of total fat.
Conclusion
Professional nutritional supervision is needed in order to improve the nutritional knowledge and eating habits of Omani athletes, and therefore improve their athletic performance.
doi:10.5001/omj.2013.103
PMCID: PMC3769126  PMID: 24044066
Athletes; Dietary intake; Nutritional Knowledge; Oman
4.  Prenatal and Postnatal Epigenetic Programming: Implications for GI, Immune, and Neuronal Function in Autism 
Autism Research and Treatment  2012;2012:190930.
Although autism is first and foremost a disorder of the central nervous system, comorbid dysfunction of the gastrointestinal (GI) and immune systems is common, suggesting that all three systems may be affected by common molecular mechanisms. Substantial systemic deficits in the antioxidant glutathione and its precursor, cysteine, have been documented in autism in association with oxidative stress and impaired methylation. DNA and histone methylation provide epigenetic regulation of gene expression during prenatal and postnatal development. Prenatal epigenetic programming (PrEP) can be affected by the maternal metabolic and nutritional environment, whereas postnatal epigenetic programming (PEP) importantly depends upon nutritional support provided through the GI tract. Cysteine absorption from the GI tract is a crucial determinant of antioxidant capacity, and systemic deficits of glutathione and cysteine in autism are likely to reflect impaired cysteine absorption. Excitatory amino acid transporter 3 (EAAT3) provides cysteine uptake for GI epithelial, neuronal, and immune cells, and its activity is decreased during oxidative stress. Based upon these observations, we propose that neurodevelopmental, GI, and immune aspects of autism each reflect manifestations of inadequate antioxidant capacity, secondary to impaired cysteine uptake by the GI tract. Genetic and environmental factors that adversely affect antioxidant capacity can disrupt PrEP and/or PEP, increasing vulnerability to autism.
doi:10.1155/2012/190930
PMCID: PMC3420412  PMID: 22934169
5.  Ethanol Lowers Glutathione in Rat Liver and Brain and Inhibits Methionine Synthase in a Cobalamin-dependent Manner 
Background
Methionine synthase (MS) is a ubiquitous enzyme that requires vitamin B12 (cobalamin) and 5-methyl-tetrahydrofolate for methylation of homocysteine to methionine. Previous studies have shown that acute or chronic ethanol (ETOH) administration results in inhibition of MS and depletion of glutathione (GSH), and it has been proposed that GSH is required for synthesis of methylcobalamin (MeCbl).
Methods
We measured GSH levels and investigated the ability of different cobalamin cofactors (cyano- (CNCbl), glutathionyl- (GSCbl), hydroxo- (OHCbl), and MeCbl) to support MS activity in liver and brain cortex from control and ETOH-treated rats.
Results
In control animals, MS activity was higher in liver than cortex for all cobalamins and MeCbl-based activity was higher than for other cofactors. S-Adenosylmethionine (SAM) was required for OHCbl, CNCbl, and GSCbl-based activity, but not for MeCbl. Feeding an ETOH-containing diet for four weeks caused a significant decrease in liver MS activity, in a cobalamin-dependent manner (OHCbl ≥ CNCbl > GSCbl > MeCbl). In brain cortex, OHCbl, CNCbl and GSCbl-based activity was reduced by ETOH treatment, but MeCbl-based activity was unaffected. GSH levels were reduced by ETOH treatment in both liver and cortex homogenates, and addition of GSH restored OHCbl-based MS activity to control levels. Betaine administration had no significant effect on GSH levels or MS activity in either control or ETOH-fed groups.
Conclusions
The ETOH-induced decrease in OHCbl-based MS activity is secondary to decreased GSH levels and a decreased ability to synthsize MeCbl. The ability of MeCbl to completely offset ETOH inhibition in brain cortex, but not liver, suggests tissue-specific differences in the GSH-dependent regulation of MS activity.
doi:10.1111/j.1530-0277.2010.01343.x
PMCID: PMC3058891  PMID: 21121936
Alcoholism; betaine; cirrhosis; methylation; vitamin B-12

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