Microhardness and Ultrastructure of Demineralized Gamma-Irradiated Human Enamel after Diode Laser (980 nm) and Fluoride Surface Treatment

Abstract Quality of life drastically diminished after radiotherapy due to radiation induced oral complications. Fluoride was found to be helpful in decreasing the incidence of radiation caries; however it has not led to elimination of dental caries. Thus, new techniques containing low fluoride concentration or not containing fluoride at all, as laser irradiation, have been studied to prevent the beginning or progression of caries. So the purpose of this study is to investigate the effect of laser surface treatment with or without fluoride on microhardness and ultrastructure of demineralized gamma irradiated enamel; Thirty enamel slabs were allocated into three groups (n=10): G slabs were subjected to gamma irradiation only; GL slabs were subjected to gamma irradiation followed by diode laser and GFL slabs were subjected to gamma irradiation followed by fluoride then diode laser. Slabs were then exposed to demineralizing solution for 72 hours. Examination of slabs was performed using vickers microhardness test and scanning electron microscope; The lowest microhardness was recorded in group G, while inGL and GFL groups it significantly increased. Scanning electron microscope revealed a pronounced loss of central prism core and retention of prism peripheries in group G. Confluence of prismatic and interprismatic structures in GL slabs and irregular rough surface with prismatic boundaries conservation in GFL slabs were detected. Applying laser improved the microhardness and counteracted the adverse effect of gamma radiation. Adding fluoride before laser irradiation had a marked effect on microhardness..

Therapeutic effect of Aloe vera and silver nanoparticles on acid-induced oral ulcer in gamma-irradiated mice

Abstract Radiation combined injury, a life-threatening condition, has higher mortality than simple radiation injury. The aim of the present study was to analyze the efficiency of Aloe vera and silver nanoparticles in improving the healing of ulcerated oral mucosa after irradiation. Thirty male Albino mice were divided into five groups: control, radiation, Aloe vera (AV), silver nanoparticles (NS), and AV+NS. The mice were exposed to whole body 6Gy gamma-radiation. After one hour, 20% acetic acid was injected into the submucosal layer of the lower lip for ulcer induction. The animals received topical treatment with the assigned substances for 5 days. Lip specimens were subjected to hematoxylin and eosin and anti alpha-smooth muscle actin immunohistochemical staining. Results demonstrated occurance of ulcer three days post irradiation in all groups except in the AV+NS group where only epithelial detachment was developed. After seven days, data revealed persistent ulcer in radiation group, and almost normal epithelium in the AV+NS group. A significant reduction of epithelial thickness was detected in all groups at the third day as compared to control. At the seventh day, only the AV+NS group restored the epithelial thickness. Area percent of alpha-smooth muscle actin expression was significantly decreased in radiation group at the third day followed by significant increase at the seventh day. However, all treatment groups showed significant increase in alpha-smooth muscle actin at the third day, which decreased to normal level at the seventh day. Our study demonstrated the efficiency of Aloe vera and silver nanoparticles in enhancing ulcer healing after irradiation.

Prevalence of Plasmid-Mediated ampC Genes in Clinical Isolates of Enterobacteriaceae from Cairo, Egypt.

Aims: To determine the prevalence of acquired pAmpCs in clinically important and relevant enterobacterial species and to characterize the molecular types of pAmpC present in our geographic area. Methodology: Sixty Enterobacterial clinical isolates resistant to third generation cephalosporins and to cephamycins were included in the study. Samples were collected for a period of 6 months between July 2008 and December 2008 from Theodor Bilharz Research Institute (TBRI), Egypt. Bacterial species were identified using API E20. AmpC genes clusters: (bla ACC, bla EBC, bla FOX, bla CMY, bla MOX, and bla DHA) were tested by PCR and DNA sequencing. Clonal relatedness of AmpC-producing Klebsiellae isolates was determined by Pulsed Field Gel Electrophoresis (PFGE). Results: AmpC genes were detected in 28.3% (17/60) of the study population including E. coli, Klebsiella and Proteus mirabilis (P mirabilis). CMY-2 enzyme was found disseminating in all 6 AmpC-positive Escherichia coli (E. coli) and in 6/10 of Klebsiellae species. Only one Klebsiella pneumonia (K. pneumonia) isolate harbored CMY-4 while DHA-1 was detected in 3 Klebsiellae and in one P. mirabilis isolate. PFGE patterns showed no clonal relatedness among the 6 CMY-2-positive Klebsiella isolates. Conclusion: Plasmid-mediated AmpC enzymes are important mechanisms of resistance to ß- lactam drugs. CMY-2 and DHA-1 are the most common gene clusters of pAmpC in our region. AmpC-type resistance in our hospital setting is not due to the dissemination of clonal strains but due to the spread of resistant genes. This is the first report from Egypt identifying DHA-1 and CMY-4 in enterobacterial isolates.