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Pouch Tissues (pouch + tissue)
Selected AbstractsEffects of low-level laser therapy on collagen expression and neutrophil infiltrate in 5-fluorouracil-induced oral mucositis in hamstersLASERS IN SURGERY AND MEDICINE, Issue 6 2010Nilza Nelly Fontana Lopes DDS Abstract Background and Objectives Several studies have suggested that low-level laser therapy (LLLT) can ameliorate oral mucositis; however, the mechanisms involved are not well understood. The aim of this study was to investigate the mechanisms of action of LLLT on chemotherapy-induced oral mucositis, as related to effects on collagen expression and inflammation. Materials and Methods A hamster cheek pouch model of oral mucositis was used with all animals receiving intraperitoneal 5-fluorouracil, followed by surface irritation. Animals were randomly allocated into three groups, and treated with an InGaAIP diode laser at a wavelength of 660,nm and output power of 35 or 100,mW laser, or no laser. Clinical severity of mucositis was assessed at four time-points by a blinded examiner. Buccal pouch tissue was harvested from a subgroup of animals in each group at four time-points. Collagen was qualitatively and quantitatively evaluated after picrosirius staining. The density of the neutrophil infiltrate was also scored. Results Peak clinical severity of mucositis was reduced in the 35,mW laser group as compared to the 100,mW and control groups. The reduced peak clinical severity of mucositis in the 35,mW laser group was accompanied by a decrease in the number of neutrophils and an increase in the proportion of mature collagen as compared to the other two groups. The total quantity of collagen was significantly higher in the control (no laser) group at the day 11 time-point, as compared to the 35,mW laser group, consistent with a more prolonged inflammatory response in the control group. Conclusion This study supports two mechanisms of action for LLLT in reducing mucositis severity. The increase in collagen organization in response to the 35,mW laser indicates that LLLT promotes wound healing. In addition, LLLT also appears to have an anti-inflammatory effect, as evidenced by the reduction in neutrophil infiltrate. Lasers Surg. Med. 42:546,552, 2010. © 2010 Wiley,Liss, Inc. [source] Optimal methods for fluorescence and diffuse reflectance measurements of tissue biopsy samplesLASERS IN SURGERY AND MEDICINE, Issue 3 2002Gregory M. Palmer BS Abstract Background and Objective In developing fluorescence spectroscopy systems for the in vivo detection of pre-cancer and cancer, it is often necessary to perform preliminary testing on tissue biopsies. Current standard protocols call for the tissue to be immediately frozen after biopsy and later thawed for spectroscopic analysis, but this process can have profound effects on the spectroscopic properties of tissue. This study investigates the optimal tissue handling methods for in vitro fluorescence spectroscopy studies. Study Design/Materials and Methods The epithelial tissue of the Golden Syrian hamster cheek pouch was used in this study. Three specific experiments were carried out. First, the fluorescence properties of tissues in vivo and of frozen and thawed tissue biopsies were characterized at multiple excitation wavelengths spanning the ultraviolet-visible (UV-VIS) spectrum. Next, comparison of tissue fluorescence emission spectra in vivo, ex vivo (immediately after biopsy), and after the freeze and thaw process were systematically carried out at the excitation wavelengths corresponding to the previously identified fluorescence peaks. Lastly, intensities at the excitation and emission wavelength pairs corresponding to the fluorescence peaks were measured as a function of time after biopsy. Diffuse reflectance measurements over the UV-VIS spectrum were also made to evaluate the effects of oxygenation, blood volume, and scattering on the tissue fluorescence at these different excitation,emission wavelengths. Results This study indicates that the freezing and thawing process produces a significant deviation in intensity and lineshape relative to the in vivo fluorescence emission spectral data over the entire UV-VIS range between 300 and 700 nm. By contrast, examination of ex vivo emission spectra reveals that it closely preserves both the intensity and lineshape of the in vivo emission spectra except between 500 and 700 nm. The observed deviations can be explained by the diffuse reflectance measurements, which suggest increased hemoglobin deoxygenation and wavelength dependent changes in scattering in ex vivo tissues, and increased total hemoglobin absorption in the frozen and thawed samples. Furthermore, it was found that over a time window of 1.5 hours, spectroscopic changes brought about by degradation of the tissue due to biopsy or other factors are significantly smaller (10,30% variations in intensity) than those associated with the freezing and thawing process (50,70% decrease in intensity). Conclusions It was found that the effects of freezing and thawing on the fluorescence properties of tissue are greater than any changes brought about by degradation of tissue over a time frame of 90 minutes after biopsy. Performing ex vivo fluorescence measurements within a reasonable time window has the advantage of more accurately reproducing the clinically relevant in vivo conditions in the case of the hamster cheek pouch tissue. Therefore, in tissue biopsy studies, the tissue sample should ideally be maintained in an unfrozen state prior to measurement. Lasers Surg. Med. 30:191-200, 2002. © 2002 Wiley-Liss, Inc. [source] Expression of inhibitors of apoptosis family protein in 7,12-dimethylbenz[a]anthracene-induced hamster buccal-pouch squamous-cell carcinogenesis is associated with mutant p53 accumulation and epigenetic changesINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 5 2008Shui-Sang Hsue Summary Fifty outbred Syrian golden hamsters were equally divided into three experimental groups and two control groups. The pouches of the experimental groups were painted bilaterally with a 0.5% 7,12-dimethylbenz[a]anthracene (DMBA) solution thrice a week for 3, 7 and 14 weeks. One of the control groups was applied with mineral oil while another control group remained untreated throughout the experiment. Neither survivin nor cIAP2 could be detected in any of the control tissues, whereas survivin and cIAP2 were found to be significantly increased in 3-, 7- and 14-week DMBA-treated pouches compared with the control pouches. Expression of XIAP, cIAP1 and NAIP were noted for both the control and 3-, 7- and 14-week DMBA-treated pouches, but levels were found to be significantly elevated in the experimental groups compared with the control pouches. p53 was not detected in any control tissues, but was significantly increased in 3-, 7- and 14-week DMBA-treated pouches. Direct sequencing revealed a point mutation (C,G) of p53 for pouch tissues treated with DMBA for 3 and 7 weeks, and there was a wide variation in the p53 sequence of the 14-week DMBA-treated pouch tissues, as compared with the control tissues. The control tissues had a survivin - and cIAP2 -methylated allele, whereas the DMBA-treated tissues showed no evidence of survivin - and cIAP2 -methylation. Neither the control nor DMBA-treated pouches showed evidence of XIAP -, cIAP1 - or NAIP -methylation. Our results suggest that the expression of inhibitors of apoptosis family in DMBA-induced hamster buccal-pouch squamous-cell carcinogenesis may be modulated by both genetic (mutant p53) and epigenetic mechanisms. [source] Inhibitory effect of the coffee diterpene kahweol on carrageenan-induced inflammation in ratsBIOFACTORS, Issue 1 2006Ji Young Kim Abstract Previous studies reported that kahweol, a coffee-specific diterpene, inhibits cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression in cultured lipopolysaccharide-activated macrophages. The aim of this study was to confirm the anti-inflammatory effects of kahweol by examining its effect on the inflammatory response induced by carrageenan in a rat using an acute air pouch inflammation model. Kahweol significantly reduced the levels of the inflammatory process markers in the air pouch, such as the volume of exudates, the amount of protein and the number of leukocytes and neutrophils. The levels of nitrite, TNF-a and prostaglandin E2 (PGE2) were also markedly lower in the air pouch of the kahweol-treated animals than in the controls. Immunoblot analysis showed that kahweol reduced the COX-2 and iNOS expression level in the exudate cells. The histological examination showed that there was a lower inflammatory response in the pouch tissues from the kahweol-treated animals. In addition, kahweol significantly reduced the paw edema induced by carrageenan and also markedly reduced the level of PGE2 production in the inflamed paw. These results suggest that kahweol has significant anti-inflammatory effects in vivo, which might be due to the inhibition of iNOS and COX-2 expression in the inflammatory sites. [source] | ||||||||||