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Complex Anatomy (complex + anatomy)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Primary Malignant Melanoma of the Maxillary Gingiva

DERMATOLOGIC SURGERY, Issue 3 2003
Betül Gözel Ulusal MD
BACKGROUND Mucosal malignant melanoma arising from the mucosa of the head and neck region is a rare entity, accounting for approximately 0.2% of all melanomas. Most of these lesions (80%) have occurred on the maxillary anterior gingival area, especially on the palatal and alveolar mucosa. OBJECTIVE Mucosal malignant melanomas are more aggressive than cutaneous melanomas. On the other hand, complex anatomy of this area makes complete surgical excision difficult. Thus, early diagnosis and treatment are important. METHODS We presented primary malignant melanoma of the maxillary gingiva in two cases. CONCLUSION In mucosal malignant melanoma, survival rates may be increased by early diagnosis and treatment. The clinician must carefully examine oral cavity, and pigmented lesions should be biopsied. Because some melanomas may be amelanotic, a high index of suspicion is necessary. [source]

An investigation into the relationship between apical root Impedance and canal anatomy

INTERNATIONAL ENDODONTIC JOURNAL, Issue 9 2008
S. M. Ardeshna
Aim, To investigate a possible relationship between apical root impedance and canal anatomy. Methodology, Twenty-three roots from human extracted teeth (mostly single rooted but also from molars) with different apical anatomy were selected. The apical anatomy was initially classified by staining the root tip to identify number of canal exits; after impedance measurements, the anatomy was confirmed by staining and clearing the dentine. The roots were divided into two groups; 12 had simple (S) anatomy (Vertucci type 1 with a single exit) and 11 had complex (C) anatomy (various Vertucci canal types with multiple exist). Impedance measurements were taken using a frequency response analyser at seven levels in the root (0.0, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 mm short of the apical terminus) at 14 frequencies ranging from 1120 to 100 000 Hz. Care was taken to control the temperature and other variables that could confound measurement accuracy. The impedance characteristics of individual roots were compared with 37 equivalent circuits (based on a pool created from a previous study); the best fitting equivalent circuit was selected. The equivalent circuits were used as the single outcome measure describing the impedance characteristics and correlated with the canal anatomy (S/C). Generalized estimating equations were used to perform logistic regression to analyse the data. Results, Canal anatomy had a significant (P = 0.046) effect on the equivalent circuit model. One circuit (model 10) was found to be the commonest and occurred significantly more commonly in the simple canals. The odds of prevalence of circuit model 10 were 2.2 times (odds ratio 2.17, 95% confidence interval 1.01,4.63) higher in canals with simple anatomy compared with canals with complex anatomy. Conclusions, Canal anatomy had a significant effect on the equivalent circuit describing its impedance characteristics. It should be possible to use impedance spectroscopy to clinically predict and image apical canal complexities. [source]

Physiologic Evaluation of Bifurcation Lesions Using Fractional Flow Reserve

JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2009
BON-KWON KOO M.D., Ph.D.
Functional evaluation of bifurcation lesions is more difficult than usual lesions due to their complex anatomy. Angiographic and intravascular ultrasound criteria for main branch intervention cannot be directly applied to side branch lesions due to the difference in underlying lesion characteristics, geometric changes during intervention, and the size of myocardial territory. Fractional flow reserve is a physiologic parameter which reflects both the degree of stenosis and the area of perfusion supplied by a specific coronary artery. The present review will focus on using fractional flow reserve in bifurcation lesions. [source]

Do pathways of water movement and leaf anatomical dimensions allow development of gradients in H218O between veins and the sites of evaporation within leaves?

PLANT CELL & ENVIRONMENT, Issue 1 2004
M. M. BARBOUR
ABSTRACT The oxygen isotope enrichment of bulk leaf water (,L), is often observed to be poorly predicted by the Craig,Gordon-type models developed for evaporative enrichment from a body of water (,e). The discrepancy between ,L and ,e may be explained by gradients in enrichment within the leaf as a result of convection of unenriched water to the sites of evaporation opposing the diffusion of enrichment away from the sites; a Péclet effect. However, this effect is difficult to quantify because the velocities of water movement within the leaf are unknown. This paper attempts to model the complex anatomy of a leaf, and hence such velocities, to assess if the gradients in H218O required for a significant Péclet effect between the vein and the evaporation sites are possible within a leaf. Published dimensions of cells in wheat leaves are used to calculate the cross-sectional areas perpendicular to the flow velocities of water through assumed pathways. By combining the ratio of actual to ,slab' velocities with anatomical lengths, equivalent lengths (L) emerge. In this way, it is concluded that if water moves only through the cell walls, or from cell to cell via either aquaporins or plasmodesmata, and evaporates from mesophyll cells, or the substomatal cells, or from the peristomatal region (a total of 15 combinations of assumptions), then the 15 central estimates of the values of L are between 9 and 200 mm. Each of these central estimates is subject to uncertainty, but overall their magnitude is important and estimates of L are comparable with those made from fitting to isotopic data (8 mm for wheat). It is concluded that significant gradients in enrichment between the vein and the evaporation sites are likely. [source]