Histopathology of ameloblastoma of the jaws; some critical observations based on a 40 years single institution experience

The aim of the present study is to examine all cases of intraosseous benign ameloblastomas treated between 1970 and 2010 in a single institution and to look for a possible correlation between the histopathological aspects and the demographical and clinical parameters, as well as the treatment outcome. The data of a total number of 44 patients were retrieved from the records. Nine patients were excluded because of doubt about the correct diagnosis (8 patients) or because of an extra-osseous presentation (1 patient). No statistically significant differences were found between the histopathological (sub)types of ameloblastomas and the demographical and clinical parameters, nor between the histopathological (sub)types and treatment outcome. Of the 28 patients treated by enucleation, in 17 patients one or more recurrences occurred, with no significant predilection for any histopathological (sub)type, including the unicystic type. There were no significant differences in the recurrence rate after enucleation in patients below and above the age of 20 years either. In six out of 17 patients with a recurrence, the recurrent lesion showed a different histopathological subtype than was encountered in the primary. In two cases a change from solid/multicystic to desmoplastic ameloblastomas was noticed. In conclusion, the current histopathological classification of benign intraosseous ameloblastoma does not seem to have clinical relevance with the possible exception of the luminal unicystic ameloblastoma that has been removed in toto, unfragmented. Since no primary desmoplastic ameloblastomas were encountered in the present study no further comments can be made on this apparently rare entity. © Medicina Oral S. L

Footprint and height corrections for UAV-borne gamma-ray spectrometry studies

Advancements in the development of gamma-ray spectrometers (GRS) have led to small and lightweight spectrometers that can be used under unmanned aerial vehicles (UAVs). Airborne GRS measurements are used to determine radionuclide concentrations in the ground, among which the natural occurring radionuclides K-40, U-238, and Th-232. For successful applications of these GRS sensors, it is important that absolute values of concentrations can be measured. To extract these absolute radionuclide concentrations, airborne gamma-ray data has to be corrected for measurement height. However, the current analysis models are only valid for the height range of 50-250 m. The purpose of this study is to develop a procedure that correctly predicts the true radionuclide concentration in the ground when measuring in the UAV operating range of 0-40 m. An analytical model is developed to predict the radiation footprint as a function of height. This model is used as a tool to properly determine a source-detector geometry to be used in Monte-Carlo simulations of detector response at various elevations between 0 and 40 m. The analytical model predicts that the smallest achievable footprint at 10 m height lies between 22 and 91 m and between 40 and 140 m at 20 m height. By using Monte-Carlo simulations it is shown that the analytical model correctly predicts the reduction in full energy peak gamma-rays, but does not predict the Compton continuum of a spectrum as a function of height. Therefore, Monte-Carlo simulations should be used to predict the shape and intensity of gamma-ray spectra as a function of height. A finite set of Monte-Carlo simulations at intervals of 5 m were used for the analysis of GRS measurements at heights up to 35 m. The resulting radionuclide concentrations at every height agree with the radionuclide concentration measured on the ground

The role of a labial salivary gland biopsy in the diagnostic procedure for Sjögren's syndrome: a study of 94 cases

Objectives: The purpose of the present study is to examine the role of the outcome of the labial salivary gland biopsy (LSGB) in the diagnostic procedure of patients suspected of suffering from Sjögren's syndrome (SS). Material and Methods: In a retrospective study the result of histopathological assessment of 94 consecutively taken labial salivary gland biopsies has been examined. For the diagnosis of SS the American-European Consensus Group classification (AECG, 2002) have been used. The outcome of the assessment has been discussed in relation to a recently reported classification provided by the American College of Rheumatology (ACR, 2012). Results: In the 94 LSGBs support for a diagnosis of SS has been encountered in 24 out of 26 patients with SS. In the 68 patients with a negative diagnosis of SS only six positive LSGBs were observed. The sensitivity of the labial biopsy amounted 0.92; the specificity was 0.91, while the positive predictive value and the negative predictive value amounted 0.80 and 0.97 respectively. LSGBs taken by or on the request of the departments of Rheumatology or Internal Medicine had a significant higher yield compared to LSGBs taken in other clinical departments. Conclusion s : The LSGB may play a role in the diagnostic procedure of Sjögren's syndrome when using either the AECG classification or the ACR classification. A LSGB should preferably taken after counseling for the possible presence of SS by a department of Rheumatology or Internal Medicine since the yield of such biopsies is much higher than in patients who have not been counseled by these departments prior to the taking of a LSGB. When using the ACR classification, a positive serologic result and a positive ocular test make the taking of a LSGB redundant. Only in case of a negative serologic outcome or a negative result of the ocular test a LSGB is indicated. Since both the serologic test and the ocular test carry hardly any morbidity, these tests should, indeed, be performed first before considering to take a LSGB

Seasonal diet changes in elephant and impala in mopane woodland

Elephant and impala as intermediate feeders, having a mixed diet of grass and browse, respond to seasonal fluctuations of forage quality by changing their diet composition. We tested the hypotheses that (1) the decrease in forage quality is accompanied by a change in diet from more monocots in the wet season to more dicots in the dry season and that that change is more pronounced and faster in impala than in elephant; (2) mopane (Colophospermum mopane), the most abundant dicot species, is the most important species in the elephant diet in mopane woodland, whereas impala feed relatively less on mopane due to the high condensed tannin concentration; and (3) impala on nutrient-rich soils have a diet consisting of more grass and change later to diet of more browse than impala on nutrient-poor soils. The phosphorus content and in vitro digestibility of monocots decreased and the NDF content increased significantly towards the end of the wet season, whereas in dicots no significant trend could be detected. We argue that this decreasing monocot quality caused elephant and impala to consume more dicots in the dry season. Elephant changed their diet gradually over a 16-week period from 70% to 25% monocots, whereas impala changed diets rapidly (2-4 weeks) from 95% to 70% monocots. For both elephants and impala, there was a positive correlation between percentage of monocots and dicots in the diet and the in vitro digestibility of these forage items. Mopane was the most important dicot species in the elephant diet and its contribution to the diet increased significantly in the dry season, whereas impala selected other dicot species. On nutrient-rich gabbroic soils, impala ate significantly more monocots than impala from nutrient-poor granitic soils, which was related to the higher in vitro digestibility of the monocots on gabbroic soil. Digestibility of food items appears to be an important determinant of diet change from the wet to the dry season in impala and elephants

‘A Tale of Two cities: Rotterdam, Amsterdam and Their Immigrants’

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