[Endocarditis prevention--what is reliable?].
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Antibiotic Prophylaxis↗
Biomedical subjects
R Rahn
Publications and source records attributed to R Rahn.
DNA structural integrity and base composition affect ultraviolet light-induced oxidative DNA damage.
We previously demonstrated that ultraviolet (UV) light (254 nm) induced the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA via a singlet oxygen mechanism. In the present paper, we provide novel findings that DNA structure and base composition significantly affect the yield of 8-OHdG by UV radiation. Unlike ionizing radiation that induces 8-OHdG both in free 2'-deoxyguanosine (dG) and in DNA, UV light induced 8-OHdG formation in intact DNA and polydG.dC, but not in dG. When thermally denatured DNA was irradiated with UV light, the yield of 8-OHdG was reduced by more than 80% compared to intact DNA. Oxygenation of the denatured DNA solution did not restore the yield of UV-induced 8-OHdG. Irradiation of DNA with different AT/GC ratios showed that the yield of UV-induced 8-OHdG varied in proportion to the AT content, suggesting that AT base pairs in DNA enhance generation of the oxidizing species and subsequent oxidation of dG. The natural antioxidants genistein, estradiol, protocatechuic acid (PCA), and oleanolic acid (OA) were investigated for their inhibition of UV-induced 8-OHdG. Genistein and estradiol, that intercalate into DNA as shown by a computer modeling, significantly quenched UV-induced 8-OHdG, whereas PCA and OA did not fit into DNA and exhibited weak or no effect. These results suggest that the intercalation of genistein and estradiol into DNA may alter the DNA structural integrity, interrupt the production of oxidizing species, and subsequently reduce the formation of 8-OHdG by UV radiation.
Animals↗
[Prevention of radiochemotherapy-induced mucositis. Value of the prophylactic mouth rinsing with PVP-iodine solution].
BACKGROUND: Oral mucositis is a frequent complication of radiochemotherapy. The origin of radiation-induced mucosa lesions is of iatrogenic nature although further development of mucositis is essentially influenced by infection. It can be assumed that disinfection measures should decrease the severity of mucositis induced by radiochemotherapy. Therefore, in a prospective randomised study the efficacy of prophylactic oral rinsing with a disinfection agent was investigated. PATIENTS AND METHOD: An open, randomised, prospective comparative trial was conducted with 40 patients undergoing radiochemotherapy of head and neck region due to malignant disease. The treatment scheme consisted of irradiation to tumor region and adjacent lymph nodes with a total dose of 71.3 Gy and simultaneous chemotherapy with carboplatin (60 mg/m2) on days 1 to 5 and 29 to 34. In all patients, a prophylaxis of mucositis with nystatine, rutosides, panthenol and immunoglobulin was undertaken. In addition, 20 patients rinsed oral cavity 4 times daily with povidone-iodine-solution, the comparative group rinsed with sterile water. Clinical examination of the oral mucosa was performed weekly. Onset, grading and duration of mucositis were used as main variables. RESULTS: Clinically manifested oral mucositis was observed in 14 patients of the iodine group (mean grading: 1.0) and all 20 patients of the control group (mean grading: 3.0). Total duration (mean) of clinically observed mucositis was 2.75 weeks in treatment patients and 9.25 in control patients. Median AUC (area under curve for grade vs duration) was 2.5 in iodine rinsing patients and 15.75 in control patients. All differences found between the 2 groups were statistically significant. Increased iodine incorporation was not observed. A pathological increase of thyroid hormone levels in the iodine group was not found. CONCLUSIONS: The gained results indicate that incidence, severity and duration of radiochemotherapy-induced mucositis can be significantly reduced by oral rinsing with povidone-iodine performed additionally to the standard prophylaxis scheme.
Adult↗
Prophylaxis with povidone-iodine against induction of oral mucositis by radiochemotherapy.
Oral mucositis is a frequent complication of radiochemotherapy. The origin of radiation-induced mucosal lesions is iatrogenic in nature, although further development of mucositis is essentially influenced by infection. It can be assumed that disinfection measures should decrease the severity of mucositis induced by radiochemotherapy. Therefore, in a prospective randomised study the efficacy of prophylactic oral rinsing with a disinfection agent was investigated. A randomised, prospective comparative trial was conducted with 40 patients undergoing radiochemotherapy of the head and neck region because of malignant disease. The treatment scheme consisted of irradiation to the tumour region and adjacent lymph nodes, with a total dose of 71.3 Gy, and simultaneous chemotherapy with carboplatin (60 mg/m2) on days 1-5 and 29-34. In all patients mucositis prophylaxis with nystatin, rutosides, panthenol and immunoglobulin was undertaken. In addition, 20 patients rinsed the oral cavity 4 times daily with povidone-iodine solution, while the group for comparison rinsed with sterile water. Clinical examination of the oral mucosa was performed weekly. Onset, grading and duration of mucositis were used as the main variables. Clinically manifest oral mucositis was observed in 14 patients in the iodine group (mean grading: 1.0) and in all 20 patients in the control group (mean grading: 3.0). The total duration (mean) of clinically observed mucositis was 2.75 weeks in treatment patients and 9.25 weeks in control patients. Median AUC (area under curve for grade vs duration) was 2.5 in the iodine rinsing patients and 15.75 in control patients. All differences found between the two groups were statistically significant. Increased iodine incorporation was not observed. A pathologic rise in thyroid hormone levels was not found in the iodine group. The results obtained indicate that incidence, severity and duration of radiochemotherapy-induced mucositis can be significantly reduced by oral rinsing with povidone-iodine in addition to the standard prophylaxis scheme. It can be concluded that rinsing with povidone-iodine is an easy, cheap and safe prophylactic method and can be recommended as a supportive treatment during antineoplastic treatment of the head and neck region.
Adult↗
Iodouracil as a personal dosimeter for solar UVB.
A solution of iodouracil (0.2 mg/mL) and KI (0.1 M) in 0.23 M borate buffer (pH 7) forms triiodide upon exposure to UVB. In the presence of thyodene, the blue starch-iodine complex is formed, the intensity of which is proportional to the amount of UVB exposure. Studies were conducted using either a sunlamp or solar irradiation to generate the triiodide endpoint. Samples (1 mL each) were placed in a plastic 24 well sample holder for exposure, and the intensity of the light at each well was controlled by placing a template over the holder with apertures of various sizes (0.4-1.5 cm) to vary the amount of light incident on each sample. The endpoint was measured using a spectrometer to monitor the absorbance increase at 400 nm of each sample or a densitometer to monitor the optical density of a photograph of the resulting solutions. The selectivity for UVB was demonstrated by irradiating through a UVB cutoff filter that reduced the sunlamp yield by 98.5% and the solar radiation yield by 94%. The correlation between the observed absorbance changes at 400 nm and the amount of absorbed energy was shown to be approximately the same for both types of radiation and the resulting quantum yield calculated to be approximately 1%, consistent with the value obtained previously for 5-iododeoxyuridine using monochromatic radiation. It is proposed that this system be incorporated into a personal dosimeter for monitoring solar UVB exposures, where the degree of exposure can be estimated either by visual inspection or, for more quantitative analysis, by UV spectroscopy.
Humans↗
Singlet oxygen involvement in ultraviolet (254 nm) radiation-induced formation of 8-hydroxy-deoxyguanosine in DNA.
In the present article, we report that ultraviolet (UV 254 nm) radiation substantially induced the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in purified DNA. The formation of 8-OHdG, a hallmarker of oxidative DNA damage, increased linearly up to 25 kJ/m2 and was dependent on the presence of oxygen in the solution. Deoxygenation by nitrogen significantly reduced the yield of 8-OHdG by UV radiation, whereas oxygenation with 100% oxygen substantially enhanced the yield. The hydroxyl radical (HO.) scavenger dimethysulfoxide (DMSO) dramatically quenched the formation of 8-OHdG by the ionizing radiation and Fenton reaction, but enhanced the formation of UV-induced 8-OHdG. Further studies showed that DMSO and mannitol, two predominant HO. scavengers, enhanced the levels of UV-induced 8-OHdG in a dose-dependent fashion, suggesting that UV-induced 8-OHdG is independent of the generation of HO.. The use of deuterium oxide (D2O), which prolongs the half life of singlet oxygen (1O2), substantially enhanced the yield of 8-OHdG by UV radiation, but not that by Fenton reaction. In contrast, sodium azide, a more and less specific 1O2 quencher, substantially reduced the levels of 8-OHdG by both UV radiation and Fenton reaction, indicating that sodium azide lacks the quenching specificity of 1O2 and HO.. It is proposed that UV induced 8-OHdG proceeds through a singlet oxygen involvement mechanism, rather than the generation of hydroxyl radicals.
8-Hydroxy-2'-Deoxyguanosine↗
Povidone-iodine to prevent mucositis in patients during antineoplastic radiochemotherapy.
In an open study, the efficacy of povidone-iodine in the prophylaxis of mucositis during antineoplastic radiochemotherapy was determined. 40 patients were randomly assigned to a treatment or control group (each 20 patients). All patients received standard prophylaxis of mucositis with nystatin, dexpanthenol, rutoside and immunoglobulin. In addition, the patients of the treatment group performed 4 times daily rinsing with povidone-iodine, the control patients with sterile water. Clinical examination of the oral mucosa was performed weekly during the radiation period and up to 6 weeks after the end of therapy. Oral mucositis was observed in 14 patients of the treatment group (mean grading: 1.0) and in all 20 patients of the control group (mean grading: 3.0). The mean onset of mucositis was after 2.25 weeks in treatment patients and 1.5 weeks in control patients. The mean total duration of mucositis was 2.75 weeks in treatment patients and 9.25 weeks in control patients. The mean AUC values were 2.5 in treatment patients and 15.75 in control patients. All findings were statistically significantly different between the two groups. It is concluded that rinsing with povidone-iodine reduces the incidence, severity and duration of oral mucositis during antineoplastic radiochemotherapy.
Adult↗
Clinical pharmacokinetics of articaine.
Articaine is the most widely used local anaesthetic agent in dentistry in a number of European countries. The amide structure of articaine is similar to that of other local anaesthetics, but it contains an additional ester group which is quickly hydrolysed by esterases. High performance liquid chromatography has been used to determine the concentrations of articaine and its metabolite articainic acid in serum. Rapid sample preparation is critical in the accurate determination of articaine serum concentrations, since blood and serum are the sites of metabolism. The time to maximum drug concentrations of articaine occurs about 10 to 15 minutes after submucosal injection of articaine 4% 80 mg, irrespective of epinephrine (adrenaline). The mean maximum plasma drug concentration is about 400 micrograms/L for articaine with epinephrine 1:200,000 and 580 micrograms/L for articaine without epinephrine. The elimination half-time of articaine is about 20 minutes. The rapid breakdown of articaine to the inactive metabolite articainic acid is related to a very low systemic toxicity and consequently to the possibility of repeated injections. Equal analgesic efficacy along with lower systemic toxicity (i.e. a wide therapeutic range) permits the use of articaine in higher concentrations than other amide-type local anaesthetics. Complete anaesthesia can be observed in nearly 90% of all cases, using articaine 4% 60 to 80 mg with epinephrine 1:200,000. Articaine is better able to diffuse through soft tissue and bone than other local anaesthetics. The concentration of articaine in the alveolus of a tooth in the upper jaw after extraction was about 100 times higher than that in systemic circulation. The plasma protein binding rate of articaine and articainic acid is 70%. It has been concluded that an unintentional intravascular injection of articaine 80 mg does not cause toxic effects in healthy individuals.
Alveolar Process↗
In vivo dose increase in the presence of dental alloys during 60Co-gamma-ray therapy of the oral cavity.
During irradiation of the mouth cavity, dental metallic materials emit secondary electrons and thus increase the applied radiation dose in their vicinity. Therefore, local destruction of the mucous membrane contacting metallic dental crowns and fillings may be observed. Available data on this dose increase are based on measurements with beam arrangements perpendicular to the metallic surface. Since the dose modification depends on the beam direction in relation to specimen surface, a reliable prediction of dose modification in the close vicinity of dental caps on fillings under complex beam arrangements, as applied in the irradiation of head and neck region from the published data is not possible. Therefore, we measured dose increase in the immediate surrounding of metallic dental material using thermoluminescence dosimetry on the phantom and during routinely applied 60Co gamma ray therapy. Phantom measurements were carried out using several oblique irradiation angles and rotational therapy. In vivo measurements were carried out at alloy specimens containing gold, palladium, and amalgam in six patients and at permanently fixed golden teeth in five patients. In vivo, the following relative dose increase values according to a simultaneously measured reference value were obtained at the surface of different dental materials: 61% for fixed golden caps. 68% for the specimen containing gold, 33% for the specimen of palladium and 61% for the specimen of amalgam. The measured dose increases due to metallic dental material during routinely applied external 60Co beam irradiation are lower compared with those of perpendicular beam arrangements. Although, the extent of dose modification is less than expected, we still advocate protection of the oral mucosa to prevent painful lesion spots.
Cobalt Radioisotopes↗
Preventing post-treatment bacteremia: comparing topical povidone-iodine and chlorhexidine.
It is well known that the occurrence of bacteremia after dental procedures can place certain patients at risk for bacterial endocarditis. The authors compared the efficacy of two antiseptic agents in the prevention of post-treatment bacteremia in 120 dental patients. Before treatment, dentists irrigated the gingival sulcus of each patient with 10 percent povidone-iodine, 0.2 percent chlorhexidine or sterile water. The authors report lower levels of bacteremia among patients treated with the povidone-iodine solution.
Adult↗
[The in-vivo determination of dosage intensification due to dental alloys in the therapeutic irradiation of the oral cavity].
BACKGROUND: In the course of therapeutic irradiation of regions in the mouth cavity dosage increase due to the emission of secondary electrons in the vicinity of dental materials can be observed. This could induce local destruction of the mucous membrane in contact with metallic dental crowns and fillings. As at now, only rough estimates of this dosage increase could be made with the help of measurements carried out with models. PATIENTS AND METHODS: The degree of dosage increase in the immediate surrounding of metallic dental material was measured in an in-vivo study during therapeutic irradiation with 60Co gamma rays in the area of mouth cavity of 11 patients. Measurements were carried out by thermoluminescent dosimetry at permanently fixed golden teeth and alloy specimens containing gold and palladium and amalgam. RESULTS: The following relative dosage values according to a simultaneously measured reference value were measured at the surface of the different dental materials: 161% near fixed golden caps, 168% near the specimen containing gold in a high percentage, 133% near the specimen of palladium and 161% near the specimen of amalgam. CONCLUSION: The in vivo measured dosage increases due to metallic dental prosthesis are less than values obtained using back scatter arrangements for irradiating phantoms. Despite this, they could be of clinical relevance. Thus the usage of a mucous membrane protection during irradiation with 60Co, as a means of preventing local lesions of the oral mucosa, due to dental alloys within the treatment volume remains inevitable.
Cobalt Radioisotopes↗
Review presentation on povidone-iodine antisepsis in the oral cavity.
Due to the great number of different micro-organisms present, the oral cavity is an important source of infection. Infections caused by these micro-organisms can occur as local infections of the oral mucous membrane, local infections of the soft tissues or the bones following surgical intervention, or endocarditis due to bacteraemia following dental surgery. In the therapy of periodontal diseases, the application of antiseptic solutions is indicated to inhibit or reduce plaque accumulation. Povidone-iodine (PVP-I) solution will reduce inflammation and the progression of periodontal disease. The application of antiseptics in the oral mucous membrane is also indicated to prevent wound infections following surgical intervention in patients with leukaemia, AIDS, immunosuppressant therapy and patients undergoing anti-neoplastic radiation or chemotherapy. Some trials on the antibacterial efficacy of PVP-I in vivo showed reduction factors of log 2-3. PVP-I may therefore be recommended as an oral antiseptic. The irrigation of the gingival sulcus with an antiseptic solution is a useful complement to antibiotic prophylaxis in patients at risk of bacterial endocarditis. Many trials on the effectiveness of PVP-I on dental extraction bacteraemia have shown a significant benefit in the active group in comparison with the control group.
Administration, Topical↗
[Antibiotics in dental practice].
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Anti-Bacterial Agents↗
[Frequency of accidental findings on panoramic X-ray films].
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Humans↗
[Efficiency of a 2% epinephrine-free Articain solution (Ultracain 2%) for dental local anesthesia].
In a prospective, randomized study it was researched whether epinephrine-free Articain 2%-solution is suitable for dental surgery. The estimated local anesthetic effect was subjective considering a dental operation an in comparison with the usual Articain 4% solution with an epinephrine addition of 1:200,000 (Ultracain D-S). The local anesthetic effect of the 2% solution was clearly lower than that of the 4% solution. However, in many cases even the lower doses of the 2% solution was sufficient for dental treatment including surgery. The higher efficiency of the 4% solution is more a result of a higher concentration than of anesthesia. In principle, the epinephrine-free 2% Articain solution is suitable for dental surgery, although, due to a shorter anesthetic duration and an unsure effect additional injections have to be given more often.
Adolescent↗
[Clinical results of filling intraoral bone defects with ionomeric porous microimplants (V-Os)].
In a clinical trial over a period of two years 50 cavities were filled up with an ionomeric porous micro implant (V-Os)* as bone replacement material after apicectomy and excision of cysts. Primary healing was found in 43 cases. 3 months after the operation 44 of 46 examined cases showed no pathological signs. In two cases the material had to be removed. 2 years after the operation 35 cases should be examined, in one case there was a fistula, the other cases showed no pathological signs. The comparison of the individual reproducible X-ray pictures after 3, 6, 12 and 24 months shows a bone regeneration next to the implanted micro implant.
Alveolar Bone Loss↗
[Study of traffic aptitude in relation to dental interventions].
Applying a video game the traffic aptitude of patients was investigated before and after dental surgical treatment and local anesthesia. Local anesthesia or operative removal of impacted third molars does not reduce the psychophysical performance important for driving a car if there is no influence of other factors. The consequences of the obtained results are discussed even under forensic aspects.
Anesthesia, Dental↗
[Effect of low blood alcohol concentrations in relation to time of day].
The physical performance of 23 persons was tested at different time of day (morning, noon, evening) under the influence of low doses of alcohol (0.8%). The results obtained indicate, that the capability of performing the tests was remarkable reduced. In the evening the effect of alcohol was significantly higher than at noon and morning; the time of recovery was also prolonged. Under these aspects the limit of 0.8% for car drivers in (West) Germany has to be reconsidered.
Adult↗