Biopsy vs. superficial scraping: detection of human papillomavirus 6, 11, 16, and 18 in potentially malignant and malignant oral lesions.

BACKGROUND: Several epidemiologic studies have shown a broad variation in the prevalence of human papillomavirus (HPV) in oral precancerous tissues and oral carcinomas. METHODS: Biopsies and superficial scrapes of lesions, clinically suspected of HPV infection, were taken from patients with potentially malignant and malignant oral lesions, and subject to HPV DNA detection by PCR-Southern blot analysis. RESULTS: From 22 patients with potentially malignant and malignant lesions analyzed, 41% of the biopsies were HPV DNA positive, whereas 95-100% of the superficial scrapes were positive (McNemar, P < 0.0001). Clinical presumption of HPV infection detected 67% (P < 0.0001) of the HPV DNA positive cases compared with 48% (P < 0.0001) determined by cytology and histopathology. The prevalence of HPV 6, 11, 16 and 18 in the oral mucosa was studied in 59 individuals. While 9% of normal controls were HPV DNA positive, 100% of the patients with potentially malignant and malignant lesions were HPV DNA positive, and the prevailing genotype was HPV 16 followed by HPV 18. CONCLUSIONS: The higher HPV DNA detection rate in superficial oral scrapes than in biopsies suggests that accurate epidemiological information on oral HPV infection/oral carcinogenesis depends not only on the DNA detection technique, but also on the tissue/cell sampling procedure.

The accumulation of the rare earth elements and of scandium in successive needle age classes of Norway spruce.

The endogenous concentrations of Sc, La, Ce, Sm, Eu, Tb, Yb, and Lu were determined by neutron activation analysis in up to five successive needle age classes of Norway spruce (Picea abies). Trees from nine sites over different bedrocks were sampled individually. Concentration values found are generally much lower than those reported in the literature. This is attributed to the careful removal of any aerosols or soil particles from the needle surface prior to analysis. The concentration of each element increases linearly with the needle age class, i.e., the accumulation can be characterized by just one parameter, the yearly increment. This pattern is followed at small as well as at large concentrations. The accumulation behavior of the investigated elements is identical to that of Si. The relative concentrations of the rare earth elements (REE) in the needles are similar to those in the earth crust. There are significant correlations between the individual REE and between Sc and La.

Rubidium and cesium in spruce needles. Concentrations and biodynamics.

The endogenous concentrations of Rb and Cs have been determined in needles of 56 trees (Norway spruce, Picea abies) from eight different sites. Analysis was done by instrumental neutron activation. Concentrations were found to have a very large range (3-28,000 ng Cs/g and 1-190 micrograms Rb/g). The values on a given site have a tendency toward a log-normal distribution. There is a significant correlation between Rb and Cs, but the correlation is not linear. The concentrations of both elements are a function of the needle age. They decrease smoothly, approaching a constant value, when going from needle age class 1 to 5. It is shown that one algebraic function describes this biodynamic behavior on all sites and at all concentration levels. The function and its parameters are discussed.

Activation analysis of human diet samples with epithermal neutrons.

Activation of diet samples by epithermal reactor neutrons is a very sensitive method for the determination of iodine. The method was developed and optimized for its determination. However, it turned out that with the same measurement valid results were also obtained for Br, Cl, K, Na, and P. The procedure involves the irradiation of the sample in a boron nitride (BN) container for 1 min, followed by gamma-counting for 20 min after a decay time of 7-15 min. The necessary sample weight is 0.5 g (dry), and no chemical operations have to be performed. The capacity is 15 samples per working day, and results are available immediately.