Context: Altered vitamin D and calcium homeostasis may play a role in the development of type 2 diabetes mellitus (type 2 DM). Evidence Acquisition and Analyses: MEDLINE review was conducted through January 2007 for observational studies and clinical trials in adults with outcomes related to glucose homeostasis. When data were available to combine, meta-analyses were performed, and summary odds ratios (OR) are presented. Evidence Synthesis: Observational studies show a relatively consistent association between low vitamin D status, calcium or dairy intake, and prevalent type 2 DM or metabolic syndrome [OR (95% confidence interval): type 2 DM prevalence, 0.36 (0.16–0.80) among nonblacks for highest vs. lowest 25-hydroxyvitamin D; metabolic syndrome prevalence, 0.71 (0.57–0.89) for highest vs. lowest dairy intake]. There are also inverse associations with incident type 2 DM or metabolic syndrome [OR (95% confidence interval): type 2 DM incidence, 0.82 (0.72–0.93) for highest vs. lowest combined vitamin D an...

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The Role of Vitamin D and Calcium in Type 2 Diabetes. A Systematic Review and Meta-Analysis

The terms 'antioxidant', 'oxidative stress' and 'oxidative damage' are widely used but rarely defined. This brief review attempts to define them and to examine the ways in which oxidative stress and oxidative damage can affect cell behaviour both in vivo and in cell culture, using cancer as an example.

Biochemistry of oxidative stress

Vitamin D deficiency predisposes individuals to type 1 and type 2 diabetes, and receptors for its activated form—1α,25-dihydroxyvitamin D3—have been identified in both beta cells and immune cells. Vitamin D deficiency has been shown to impair insulin synthesis and secretion in humans and in animal models of diabetes, suggesting a role in the development of type 2 diabetes. Furthermore, epidemiological studies suggest a link between vitamin D deficiency in early life and the later onset of type 1 diabetes. In some populations, type 1 diabetes is associated with certain polymorphisms within the vitamin D receptor gene. In studies in nonobese diabetic mice, pharmacological doses of 1α,25-dihydroxyvitamin D3, or its structural analogues, have been shown to delay the onset of diabetes, mainly through immune modulation. Vitamin D deficiency may, therefore, be involved in the pathogenesis of both forms of diabetes, and a better understanding of the mechanisms involved could lead to the development of preventive strategies.

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Vitamin D and diabetes.

Periodontal diseases are prevalent both in developed and developing countries and affect about 20-50% of global population. High prevalence of periodontal disease in adolescents, adults, and older individuals makes it a public health concern. Several risk factors such as smoking, poor oral hygiene, diabetes, medication, age, hereditary, and stress are related to periodontal diseases. Robust evidence shows the association of periodontal diseases with systemic diseases such as cardiovascular disease, diabetes, and adverse pregnancy outcomes. Periodontal disease is likely to cause 19% increase in the risk of cardiovascular disease, and this increase in relative risk reaches to 44% among individuals aged 65 years and over. Type 2 diabetic individuals with severe form of periodontal disease have 3.2 times greater mortality risk compared with individuals with no or mild periodontitis. Periodontal therapy has been shown to improve glycemic control in type 2 diabetic subjects. Periodontitis is related to maternal infection, preterm birth, low birth weight, and preeclampsia. Oral disease prevention strategies should be incorporated in chronic systemic disease preventive initiatives to curtail the burden of disease in populations. The reduction in the incidence and prevalence of periodontal disease can reduce its associated systemic diseases and can also minimize their financial impact on the health-care systems. It is hoped that medical, dental practitioners, and other health-care professionals will get familiar with perio-systemic link and risk factors, and need to refer to the specialized dental or periodontal care.

Prevalence of periodontal disease, its association with systemic diseases and prevention.

The adverse long-term effects of diabetes mellitus have been well described and involve many organ systems. While diabetes management has largely focused on control of hyperglycemia, the presence of abnormalities of angiogenesis may cause or contribute to many of the clinical manifestations of diabetes. When compared with non-diabetic subjects, diabetics demonstrate vascular abnormalities of the retina, kidneys, and fetus. Diabetics have impaired wound healing, increased risk of rejection of transplanted organs, and impaired formation of coronary collaterals. In each of these conditions, and possibly in diabetic neuropathy as well, abnormalities of angiogenesis can be implicated in the pathogenesis. A perplexing feature of the aberrant angiogenesis is that excessive and insufficient angiogenesis can occur in different organs in the same individual. In this review, the clinical features, molecular mechanisms, and potential therapeutic options of abnormal angiogenesis in diabetes will be reviewed. © 2002 Wiley Periodicals, Inc. Med Res Rev, 23, No. 2, 117–145, 2003

Abnormal angiogenesis in diabetes mellitus.

Serum 1,25 dihydroxy vitamin D (1,25(OH)2D3), 25 hydroxy vitamin D (25(OH)D) and parathormone levels in diabetic retinopathy.

Oxygen radical release has been proposed as a pathogenic factor of the ethanol-induced acute gastric injury. Melatonin, a pineal hormone, is known to scavenge oxygen free radicals. We investigated whether parenteral administration of melatonin prevented ethanol-induced macroscopic damage, polymorphonuclear (PMN) leukocyte infiltration, depletion of total glutathione (tGSH) concentration, and glutathione reductase (GSSG-Rd) activity in the rat gastric mucosa. We compared the effects of melatonin with those of omeprazole. Ethanol-induced mucosal damage was evaluated using three different parameters: gastric total glutathione (tGSH) concentration and glutathione reductase (GSSG-Rd) activity, the number of PMN leukocytes, and macroscopic investigation. Gatric tGSH concentration and GSSG-Rd activity decreased and the number of PMNs increased after ethanol administration. It was found that pretreatment with melatonin increased both tGSH concentration and GSSG-Rd activity. Melatonin also reduced ethanol-induced PMN infiltration in the stomach. Ethanol administration damaged the entire gastric mucosa. Melatonin significantly decreased the extent of ethanol-induced macroscopic injury. In conclusion, these findings support the conclusion that the protection conferred by melatonin in gastric ulcer is presumably due to its antioxidant activity.

Melatonin Prevents Ethanol-Induced Gastric Mucosal Damage Possibly Due to Its Antioxidant Effect

The increasing use of mobile telephones raises the question of possible adverse effects of the electromagnetic fields (EMF) that these phones produce. In this study, we examined the oxidative stress in the brain tissue and serum of rats that resulted from exposure to a 900-MHz EMF at a whole body average specific absorption rate (SAR) of 1.08W/kg for 1h/day for 3 weeks. We also examined the antioxidant effect of garlic powder (500mg/kg/day) given orally to EMF-exposed rats. We found that malondialdehyde (MDA) (p , 0.001) and advanced oxidation protein product (AOPP) (p , 0.05) increased in rat brain tissue exposed to the EMF and that garlic reduced these effects (p , 0.05). There was no significant difference in the nitric oxide (NO) levels in the brain. Paraoxonase (PON) was not detected in the brain. There was a significant increase in the levels of NO (p , 0.001) detected in the serum after EMF exposure, and garlic intake did not affect this increase in NO. Our results suggest that there is a significant increase in brain lipid and protein oxidation after electromagnetic radiation (EMR) exposure and that garlic has a protective effect against this oxidative stress.

Effect of 900 MHz radiofrequency radiation on oxidative stress in rat brain and serum.

Background: This study evaluates the effects of initial periodontal treatment on the gingival crevicular fluid (GCF) and salivary levels of 8-hydroxy-deoxyguanosine (8-OHdG) as a marker of oxidative deoxyribonucleic acid (DNA) damage in patients with chronic periodontitis (CP).Methods: At baseline, clinical parameters were determined and GCF and saliva samples were obtained from 24 patients with CP and 24 individuals with clinically healthy periodontium. GCF, saliva samples, and clinical periodontal measurements were repeated at day 10, 1 month, and 3 months following initial periodontal therapy in patients with CP. 8-OHdG levels of GCF and saliva samples were investigated by using an enzyme-linked immunosorbent assay.Results: Statistically significant higher 8-OHdG levels of GCF and a significant decrease after initial periodontal therapy were determined in the CP group (P <0.001). A significant positive correlation was found between 8-OHdG levels of GCF and clinical periodontal measurements (P <0.001). ...

8-Hydroxy-Deoxyguanosine Levels in Gingival Crevicular Fluid and Saliva in Patients With Chronic Periodontitis After Initial Periodontal Treatment

Purpose: We aimed to study the oxidative damage induced by radiofrequency electromagnetic radiation (RF-EMR) emitted by mobile telephones and the protective effect of garlic extract used as an anti-oxidant against this damage.Materials and methods: A total of 66 albino Wistar rats were divided into three groups. The first group of rats was given 1.8 GHz, 0.4 W/kg specific absorption rate (SAR) for 1 h a day for three weeks. The second group was given 500 mg/kg garlic extract in addition to RF-EMR. The third group of rats was used as the control group. At the end of the study, blood and brain tissue samples were collected from the rats.Results: After the RF-EMR exposed, the advanced oxidation protein product (AOPP) levels of brain tissue increased compared with the control group (p < 0.001). Garlic administration accompanying the RF-EMR, on the other hand, significantly reduced AOPP levels in brain tissue (p < 0.001). The serum nitric oxide (NO) levels significantly increased both in the first and ...

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Papers

Serum 1,25 dihydroxy vitamin D (1,25(OH)2D3), 25 hydroxy vitamin D (25(OH)D) and parathormone levels in diabetic retinopathy.

Melatonin Prevents Ethanol-Induced Gastric Mucosal Damage Possibly Due to Its Antioxidant Effect

Effect of 900 MHz radiofrequency radiation on oxidative stress in rat brain and serum.

8-Hydroxy-Deoxyguanosine Levels in Gingival Crevicular Fluid and Saliva in Patients With Chronic Periodontitis After Initial Periodontal Treatment

Oxidative stress induced by 1.8 GHz radio frequency electromagnetic radiation and effects of garlic extract in rats.