Detection of oral dysplasia in animals with fluorine-18-FDG and carbon-11-tyrosine

The uptake of 18F-fluorodeoxyglucose (FDG) and L-[1-(11)C]tyrosine (TYR) was investigated in male Wistar albino rats with chemically induced dysplasia and oral squamous cell carcinoma (SCC) to correlate the uptake values with the grade of dysplasia. METHODS: The palates of 54 rats was painted three times per week with 4-nitroquinoline 1-oxide to create different stages of dysplasia and SCC. After 2, 4, 6, 8, 12, 16, 20, 26 and 30 wk, these rats were investigated with PET. Immediately thereafter, the rats were killed and histologically prepared. Standardized uptake values (SUVs) of the palate of the rats were calculated and correlated with the Epithelial Atypia Index (EAI) and the thickness of the epithelial layer. RESULTS: The TYR SUV correlated with the EAI and the epithelial thickness, 0.5 and 0.74, respectively. No correlation could be found for FDG SUV, compared to EAI and the epithelial thickness. CONCLUSION: For dysplasia and SCC, TYR showed higher uptake values than did FDG. It appeared that, for the detection of oral dysplasia, the tissue hyperplasia was more important than malignant features of dysplastic mucosa.     

Selective decontamination of the digestive tract: effect of cessation of routine application at an ICU

BACKGROUND: Selective decontamination of the digestive tract (SDD) with non-absorbable antibiotics was extensively used at intensive care units (ICU) in Europe to prevent nosocomial infections in critically ill patients. After three recent meta-analyses in which it was demonstrated that SDD did not influence hospital stay and mortality in these patients several ICU's decided to stop the routine use of SDD. OBJECTIVE: To examine the effects of the cessation of SDD on nosocomial infections, mortality and hospital stay at an ICU in post-operative patients. DESIGN: Retro- and prospective follow-up. PATIENTS: Post-operative patients with mechanical ventilation (MV) for > or = 5 days at an ICU were included. The retrospective group (SDD group) comprised of 138 patients (mean age 66, range 10-91; 78% male) and the prospective group (non-SDD group) of 142 patients (mean age 67 range 18-85; 65% male). The SDD regime consisted of colistin, tobramycin and amphotericin B. Cessation of the SDD was accompanied by a shortening of the routine intravenous cefuroxime prophylaxis. RESULTS: There was a nonsignificant increase from an average 21 to 23 days ICU stay in the non-SDD group when compared with the SDD group (p > 0.05). Of the 280 patients 97 (35%) died on the ICU. The risk of death was lower in the non-SDD group (adjusted hazard ratio 0.7 with 95% Cl 0.5-1.1). There was a trend towards an increase in infections as a cause of death in the non-SDD group (38% of the ceased patients versus 20% in the SDD group) (p > 0.05). The incidence of respiratory tract infection (per 1000 person days) was 80 (95% Cl 48-113) in the non-SDD group versus 19 (95% Cl 8-22) in the SDD group (adjusted hazard ratio 4.5 (95% Cl 2.9-7.1)). CONCLUSION: The cessation of the routine application of SDD in post-operative patients mechanically ventilated for 5 days or more did nod adversely affect survival nor increased length of stay at the ICU. There may have been a shift to infections as a cause of death after cessation of SDD.     

In vivo detection of dysplastic tissue by Raman spectroscopy

The detection of dysplasia and early cancer is important because of the improved survival rates associated with early treatment of cancer. Raman spectroscopy is sensitive to the changes in molecular composition and molecular conformation that occur in tissue during carcinogenesis, and recent developments in fiber-optic probe technology enable its application as an in vivo technique. In this study, the potential of Raman spectroscopy for in vivo classification of normal and dysplastic tissue was investigated. A rat model was used for this purpose, in which dysplasia in the epithelium of the palate was induced by topical application of the carcinogen 4-nitroquinoline 1-oxide. High quality in vivo spectra of normal and dysplastic rat palate tissue, obtained using signal integration times of 100 s were used to create tissue classification models based on multivariate statistical analysis methods. These were tested with an independent set of in vivo spectra, obtained using signal collection times of 10 s. The best performing model, in which signal variance due to signal contributions of the palatal bone was eliminated, was able to distinguish between normal tissue, low-grade dysplasia, and high-grade dysplasia/carcinoma in situ with a selectivity of 0.93 and a sensitivity of 0.78 for detecting low-grade dysplasia and a specificity of 1 and a sensitivity of 1 for detecting high-grade dysplasia/ carcinoma in situ.     

Nodal spread of squamous cell carcinoma of the oral cavity detected with PET-tyrosine, MRI and CT

The uptake of L-1-[11C]-tyrosine (TYR) in cervical lymph nodes of eleven patients with squamous-cell carcinoma (SCC) of the oral cavity was studied with PET to detect lymphogenic metastases. METHODS: The TYR-PET results were compared with clinical, MRI, CT, histopathologic findings and historical data of patients studied with FDG. Sensitivity, specificity, accuracy and the positive and negative predictive values were calculated. RESULTS: TYR-PET had sensitivity of 83% and a specificity of 95%. In contrast, the sensitivity and specificity for MRI were 33% and 96%, respectively. The sensitivity and specificity for CT were 55% and 91%, respectively. TYR-PET results compared favorably with FDG. CONCLUSION: With TYR-PET, SCC metastases of the oral cavity can be visualized with high sensitivity and specificity. TYR-PET can be an additional tool for further evaluation of neck malignancies.     

Conductive plastic film electrodes for Pulsed Electric Field (PEF) treatment—A proof of principle

Nowadays Pulsed Electric Field (PEF) treatment of food needs to be performed prior to packaging, either hygienic or aseptic packaging is necessary. New techniques for PEF treatment after packaging can be considered when plastic conductive (film) electrodes can be integrated within the package, so that the package and the product can be treated as a whole. This paper describes a newly developed treatment chamber, which can be used to test the ability of any arbitrary plastic packaging film to be used as electrodes for PEF treatment. Tests with a flexible commercially available electrically conductive copolymer film showed that reduction of Lactobacillus plantarum by PEF was possible. This heat sealable film obeys the mechanical properties of a polymer; however it has an electrical conductivity of 0.75 S m^? 1 and approximately 2.3% of the surface area is electrically conductive. The maximum obtained inactivation was 2.1 log₁₀ with a specific energy of 17 J ml^? 1. The microbial experiments gave a consistent outcome compared with finite element simulations and with models from literature. Further research to reach real pasteurisation levels is needed as well as issues concerning utilisation of these film electrodes.Industrial relevanceStainless steel electrodes, which are widely used as electrode material for Pulsed Electric Field (PEF) treatment systems, have as main disadvantage that they exhibit certain wear. This article showed that polymer composites can be considered as electrode material for newly to be developed PEF treatment concepts. With extensive research on food grade composite films the integration of cheap disposable plastic electrodes in food packages comes within reach.     

Combined ZVS?ZCS topology for high-current direct current hybrid switches: design aspects and first measurements

Power electronic switches have been considered for load switching ever since their invention. This is because semiconductor switches enable fast, arc-less, reliable and maintenance-free switching. The main disadvantages in relation to conventional switches (i.e. circuit breakers), however, are their sensitivity to transients, high on-state losses and the presence of leakage current. The advantages of both types of switches can be exploited by combining the semiconductor and the mechanical switch and thereby their disadvantages, arc formation and regular maintenance, can also be eliminated. For hybrid switches (HSs), both zero voltage switching (ZVS) and zero current switching (ZCS) are frequently used. A new hybrid switching topology has been developed where both ZVS and ZCS techniques are applied to the mechanical switch. The `symbiosis' between these solid-state switching techniques and a mechanical switch eliminates several of the disadvantages, resulting in a more reliable direct current (DC) HS that requires less maintenance. The first turn-off measurement (up to 5 kA) from a prototype that has been developed for a 3-kV DC grid is presented