Oxidant-NO dependent gene regulation in dogs with type I diabetes: impact on cardiac function and metabolism

<p>Abstract</p> <p>Background</p> <p>The mechanisms responsible for the cardiovascular mortality in type I diabetes (DM) have not been defined completely. We have shown in conscious dogs with DM that: <it>1</it>) baseline coronary blood flow (CBF) was significantly decreased, <it>2</it>) endothelium-dependent (ACh) coronary vasodilation was impaired, and <it>3</it>) reflex cholinergic NO-dependent coronary vasodilation was selectively depressed. The most likely mechanism responsible for the depressed reflex cholinergic NO-dependent coronary vasodilation was the decreased bioactivity of NO from the vascular endothelium. The goal of this study was to investigate changes in cardiac gene expression in a canine model of alloxan-induced type 1 diabetes.</p> <p>Methods</p> <p>Mongrel dogs were chronically instrumented and the dogs were divided into two groups: one normal and the other diabetic. In the diabetic group, the dogs were injected with alloxan monohydrate (40-60 mg/kg iv) over 1 min. The global changes in cardiac gene expression in dogs with alloxan-induced diabetes were studied using Affymetrix Canine Array. Cardiac RNA was extracted from the control and DM (n = 4).</p> <p>Results</p> <p>The array data revealed that 797 genes were differentially expressed (P < 0.01; fold change of at least ±2). 150 genes were expressed at significantly greater levels in diabetic dogs and 647 were significantly reduced. There was no change in eNOS mRNA. There was up regulation of some components of the NADPH oxidase subunits (gp91 by 2.2 fold, P < 0.03), and down-regulation of SOD1 (3 fold, P < 0.001) and decrease (4 - 40 fold) in a large number of genes encoding mitochondrial enzymes. In addition, there was down-regulation of Ca²⁺cycling genes (ryanodine receptor; SERCA2 Calcium ATPase), structural proteins (actin alpha). Of particular interests are genes involved in glutathione metabolism (glutathione peroxidase 1, glutathione reductase and glutathione S-transferase), which were markedly down regulated.</p> <p>Conclusion</p> <p>our findings suggest that type I diabetes might have a direct effect on the heart by impairing NO bioavailability through oxidative stress and perhaps lipid peroxidases.</p

Average annual crestal bone loss of ITI implants following the first year of loading

BACKGROUND: Long term success of dental implants directly depends on marginal bone resorption. The aim of this study was to determine the annual average bone loss on the mesial and distal aspects of implants following the first year of implantation.&#13; METHODS: This was a descriptive analytical study of patients treated with ITI (International Team of Implantology) implants at the Dental School of Isfahan University of Medical Sciences from 1998-2002 (1377-81). A total of 15 patients with 41 implants were selected by convenience sampling method. The height of the alveolar bone was measured using panoramic radiography before and after loading with calipers to determine the average bone loss. Other information such as pocket depth, bleeding index, plaque index, gingival recession, was obtained by clinical examinations. The mean bone loss on the mesial &amp; distal sides was analyzed by ANOVA at 0.05 level of significance.&#13; RESULTS: The average bone loss on the proximal sides of ITI implants obtained annually after the first year of loading was 0.084 ± 0.035 mm with slight difference on the mesial (0.092 ± 0.035) and distal (0.072 ± 0.033) sides. There was negligible difference between male and female patients. The average survival rate for thirty three months was 95.1%.&#13; CONCLUSION: The average bone loss on the mesial and distal sides of ITI implants compared with other studies was satisfactory. Survival and success rates were acceptable.&#13; KEYWORDS: Dental implants, bone resorption, survival rate, dental plaque index

An Investigation on Metallic Ion Release from Four Dental Casting Alloys

Statement of Problem: Element release from dental casting alloys into the oral environment is of clinical concern and is considered to be a potential health problem to all patients.Purpose: The aim of this study was to investigate the metallic ion release of four base metal alloys.Materials and Methods: Two Ni-Cr (Minalux and Supercast) and two Co-Cr alloys (Minalia and Wironit) were examined. Nine specimens of each type were prepared in 13×11×1.4 mm dimensions and each of the four alloys (3 specimens per group) were conditioned in artificial saliva at 37 c for one, three and seven days.The conditioning media were analyzed for element-release using Inductive CoupledPlasma Atomic Emission Spectrophotometer (ICPAES). Collected data were statistically analyzed using ANOVA and Duncan multiple range test (P< 0.05).Results: The greatest amount of element release was seen after seven days (134.9 ppb Supercast, 159.2 ppb Minalux, 197.2 ppb Minalia, and 230.2 ppb Wironit). There was a significant difference between the released elements from the alloys after the three conditioning times (p<0.001).Conclusion: Element release from the studied alloys is proportional to the conditioning time. The Ni-Cr alloys tested in this investigation were more resistant to corrosion as compared to the Co-Cr alloys in artificial saliva. Supercast had the highest corrosion resistance

An evaluation on the adherence of Candida albicans to different denture- base materials

The surface topography of denture base material is an important factor for the&quot;nadhesion of Candida albicans and other microorganisms.&quot;nPurpose: The aim of this study was to evaluate the adherence of Candida albicans to four types of denture&quot;nbase materials (Acropars acrylic resin, Meliodent acrylic resin, rough and smooth surfaces of Molloplast B).&quot;nMaterials and Methods: Seven blocks of two types of acrylic resins and ten blocks of silicone with one&quot;nrough and one smooth surface were made and incubated in a suspension of Candida albicans. After washing,&quot;nthe blocks were stained with acridine orange and examined under fluorescent microscope. For statistical&quot;nanalysis ANOVA and Duncan tests were used.&quot;nResults: It was observed that Candida adhesion to rough surfaces of acrylic resins and silicone was&quot;nsignificantly more than polished surfaces of acrylic resins and smooth silicone (PO.0001). However, no&quot;nstatistical significant difference was found between polished acrylic resins surfaces and smooth silicone.&quot;nConclusion: Significant differences in the adherence of Candida to the surfaces of different denture base&quot;nmaterials are due to differences in surface topography, chemical, physical and hydrophobic properties so it is&quot;nrecommended to minimize the roughness and irregularities of denture base

Developing a software for removable partial denture design: Part I: Data collection

Background and Aim: Proper designing of partial denture frameworks is the duty of dentists, but this task is often abdicated to technicians because of lack of time and experience. Computer assisted learning and designing can be used for both training dental students and helping dentists design proper frameworks. As the first step to prepare software for framework designing, this study evaluated the agreement on different framework designing principles, among prosthodontists of dental schools in Iran. &quot;nMaterials and Methods: A questionnaire consisting of 121 design rules was sent to 41 prosthodontists at seven dental schools in Iran .The percentage rate of agreement on results was used for data analysis. &quot;nResults: The percentage of rules accepted by more than 60% of the prosthodontists was 76.2%. It consisted 80% saddle rules, 76.2% rest rules, 78.4% clasp rules, 63.6% maxillary major connector&apos;s rules and 80.9% mandibular major connector rules. &quot;nConclusion: The percentage of accepted rules by Iranian prosthodontists was 76.2%. Maxillary major connectors had the least acceptance