The entire colonic mucosa of 51 cases of colorectal carcinoma was examined histologically. Mucosal lesions including goblet cell hyperplasia, crypt dilatation, ulceration with regeneration, basal cell hyperplasia, metaplastic lesions, and adenomas were encountered. Goblet cell hyperplasia (80.4%) was most prominent adjacent to the carcinoma (transitional mucosa). Whether this represents a precancerous change is controversial. Crypt dilatation (57%) is considered a nonspecific change due to mucosal injury and indicates obstruction to the outlet of the crypts. Ulceration (6%) is often proximal to the carcinoma and is considered secondary to stasis and ischaemia due to obstruction. Basal cell hyperplasia is particularly prominent at the site of lymphoid follicles. It is suggested that the hyperplasia is a reactive response to the presence of stimuli in the intestinal content. It is observed that metaplastic lesions have their origin from these foci of basal cell hyperplasia. The presence of basal cell hyperplasia in metaplastic polyps (14%) indicates that they are active lesions in the process of formation and growth. The occurrence of metaplastic lesions may provide an indication of an adverse environment and a vulnerable mucosa. Adenomas have their origin from basal cells of colonic crypts. They are present in 47% of colorectal carcinoma. The findings support the view that adenomas are the most common and important precursor lesion associated with colorectal carcinoma in man. No de novo foci of malignant transformation was encountered but this does not exclude the possibility of de novo carcinogenesis of the colorectum.
Abstract:We employ a Genetic Algorithm for the dispersion optimization of a range of holey fibers (HF) with a small number of air holes but good confinement loss. We demonstrate that a dispersion of 0 ± 0.1 ps/nm/km in the wavelength range between 1.5 and 1.6 µm is achievable for HFs with a range of different transversal structures, and discuss some of the trade-offs in terms of dispersion slope, nonlinearity and confinement loss. We then analyze the sensitivity of the total dispersion to small variations from the optimal value of specific structural parameters, and estimate the fabrication accuracy required for the reliable fabrication of such fibers. Opt. Express 9, 687-697 (2001). http://www.opticsexpress.org/abstract.cfm?URI=OPEX-9-13-687 4. W. H. Reeves, J. C. Knight, P. St. J. Russell and P. J. Roberts "Demonstration of ultra-flattened dispersion in photonic crystal fibers," Opt. Express 10, 609-613 (2002). http://www.opticsexpress.org/abstract.cfm?URI=OPEX-10-14-609 5. K. P. Hansen,"Dispersion flattened hybrid-core nonlinear photonic crystal fiber," Opt. Express 11, 1503-1509 (2003). http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-13-1503 6. K. Saitoh, M. Koshiba, T. Hasegawa and E. Sasaoka, "Chromatic dispersion control in photonic crystal fibers: application to ultra-flattened dispersion," Opt. Express 11, 843-852 (2003).
Abstract:We demonstrate mode-division multiplexed WDM transmission over 50-km of few-mode fiber using the fiber's LP 01 and two degenerate LP 11 modes. A few-mode EDFA is used to boost the power of the output signal before a few-mode coherent receiver. A 6×6 time-domain MIMO equalizer is used to recover the transmitted data. We also experimentally characterize the 50-km few-mode fiber and the few-mode EDFA.
Radiotherapy for nasopharyngeal carcinoma seemed to have adverse but insignificant effects on the cognitive functions of the patients. However, for patients who developed temporal lobe necrosis after radiotherapy, memory, language, motor ability, and executive functions were significantly impaired, although their general intelligence remained relatively intact.
BACKGROUND Cognitive dysfunction is common in patients who develop radionecrosis after receiving radiotherapy for nasopharyngeal carcinoma (NPC). However, the impact of the location and volume of radionecrosis on cognitive dysfunction remains unclear. The authors found a significant association between the severity of cognitive impairment and the volume of radionecrosis; in turn, the volume of radionecrosis was affected by patient age at time radiotherapy was completed. METHODS Fifty patients with NPC who received radiotherapy were evaluated by a battery of neuropsychologic tests of cognitive function. The brain lesion volume was quantified, and the lesion locations were identified by standardized brain templates. The results of the neuropsychologic tests were correlated with lesion volume. Gender, education, age at the completion of radiotherapy, brain volume, total dose, and fractional dose were evaluated as risk factors for lesion volume. RESULTS Lesion volume was correlated significantly with the severity of cognitive deficits. Larger left‐hemisphere lesions were correlated with lower verbal memory (from P < 0.001 to P = 0.008) and language abilities (from P = 0.001 to P = 0.018), whereas larger right‐hemisphere lesions were associated with worse visual memory (from P = 0.009 to P = 0.039). Finally, patients who received radiotherapy at a younger age had smaller lesion volumes (P < 0.001). CONCLUSIONS The volume and location of radionecrosis had an influential impact on the pattern of cognitive impairment found in patients with NPC, and patient age at the time radiotherapy was completed appeared to affect the volume of radionecrosis found after radiotherapy. Cancer 2003;97:2019–26. © 2003 American Cancer Society. DOI 10.1002/cncr.11295
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