ABSTRACT
Lyotropic liquid crystal(LLC) is generally a kind of micelle association formed by self-assembly of amphiphilic lipid polymers in polar solvents. It have been applied in the study of drug delivery of administration of oral, skin injection, ocular, and cavity channel routes(including buccal cavity, nasal cavity, vagina), et al. Medical liquid crystal mainly includes lamellar phase, inverse hexagonal phase and inverse cubic phase. Inner assembling order in different structures of liquid crystals will affect the drug localization, viscosity, molecular interactions, and further drug release in vitro and in vivo, pharmacokinetics and so on. Thus, it is very important to characterize their microstructures. In this article, the characterization methods of LLC microstructures are comprehensively described based on the research of LLC as drug delivery carrier and related literatures, which can provide reference for further study of LLC drug delivery system.
ABSTRACT
BACKGROUND: Invasion of epithelial cells into the connective tissue brings about massive morphological and architectural changes in the underlying stroma. Myofibroblasts reorganize the stroma to facilitate the movement of tumor cells leading to metastasis. The aim of this study was to determine the number and pattern of distribution of myofibroblasts and the qualitative and quantitative change that they cause in the collagen present in the stroma in various grades of oral squamous cell carcinoma (OSCC). METHODS: The study was divided into two groups with group I (test group, 65 cases) consisting of 29 cases of well-differentiated squamous cell carcinoma, 25 moderately differentiated SCC, and 11 poorly differentiated SCC, and group II (control group) consisting of 11 cases of normal mucosa. Sections from each sample were stained with anti-α-smooth muscle actin (α-SMA) antibodies, hematoxylin and eosin, and Picrosirius red. Several additional sections from each grade of OSCC were stained with Masson's trichrome to observe the changes in collagen. For the statistical analysis, Fisher's exact test, Tukey's post hoc honest significant difference test, ANOVA, and the chi-square test were used, and p < .05 was considered statistically significant. RESULTS: As the tumor stage progressed, an increase in the intensity α-SMA expression was seen, and the network pattern dominated in more dedifferentiated carcinomas. The collagen fibers became thin, loosely packed, and haphazardly aligned with progressing cancer. Additionally, the mean area fraction decreased, and the fibers attained a greenish yellow hue and a weak birefringence when observed using polarizing light microscopy. CONCLUSIONS: Myofibroblasts bring about numerous changes in collagen. As cancer progresses, there isincrease in pathological collagen,which enhances the movement of cells within the stroma.
Subject(s)
Actins , Antibodies , Birefringence , Carcinoma, Squamous Cell , Collagen , Connective Tissue , Eosine Yellowish-(YS) , Epithelial Cells , Hematoxylin , Microscopy , Mucous Membrane , Myofibroblasts , Neoplasm Metastasis , Tumor MicroenvironmentABSTRACT
OBJECTIVE: To observe the time distribution characteristic of silica nanoparticles in rats after one-time intratracheal infusion. METHODS: Specific pathogen free male Wistar rats were randomly divided into one control group and7 experimental groups according to different time of intratracheal infusion( 1,3,5,7,14,21 and 28 days),6 rats in each group. The experiment groups were intratracheally instilled with 1. 0 mL silica nanoparticle suspension( mass concentration 50. 00 g/L). The control group was not given any treatment. Rats were sacrificed and their organ tissue samples such as serum,lung,spleen,liver and kidney were collected at different time points. The silicon levels of tissues were determined by inductively coupled plasma optical-emission spectrometry. The histology of rat's lungs was observed by optical microscope and the location of silica in lungs was observed by polarization microscope. RESULTS: After exposure to silica nanoparticles for 1-7 days,the changes of rats' lung tissue was mainly exudative inflammation. The changes of lung was proliferative inflammatory lesions after 14-28 days of exposure to silica nanoparticles. The visible nodules of cells were observed in the lung tissue in 28 days experiment group. The distribution of silica nanoparticles was observed obviously in the lung tissues of rats of 1 day experiment group under the polarizing microscopy. The tendency decreased with the increase of observation time. Silica nanoparticles were rarely seen 21 and 28 days after intratracheal infusion in rats. The silicon levels of serum,lung and spleen tissues reached the peak in 1 day after silica nanoparticles instillation,then dropped in 3-7 days( serum) or 3-14 days( lung and spleen tissues) and went back to that of the control group's. The level of silicon in the livers and kidneys of rats in the experimental groups showed no significant increase in the level of 1-5 day after the instillation( P > 0. 05),and showed significant increase in the level of 7 day( P < 0. 05). The level reached its peak on time points of 14 and 21 days after the instillation,and subsequently decreased,and didn't returned to normal till the 28 th day. The silicon levels of the lungs,spleens,livers and kidneys were all higher in rats than that of serum( P < 0. 05). The silicon levels of the lungs and spleens were higher than that of the livers and kidneys after instillation for1-5 days( P < 0. 05). The silicon levels of the lungs and spleens were both lower than that of the livers and kidneys after instillation for 14-28 days( P < 0. 05). CONCLUSION: Silica nanoparticles can cause lung injury when instilled intratracheally in rats. After instillation,silica nanoparticles were mainly distributed in the lungs and spleens after 1-5 days and distributed in the livers and kidneys after 14-28 days.
ABSTRACT
Background: This study is based on finding of an inexplicable artifact that was seen in the tissue received as periapical granuloma. Aim: To observe the histological appearance of different commonly implanted food particles and easily incorporated substances from a laboratory in the oral biopsy tissues. Materials and Methods: Various food particles such as wheat chapatti, beans, peas, pulses, and coriander leaves and substances such as a suture, cotton, and paper that can easily gain entry during biopsy and histotechnical procedures were intentionally introduced in the tissue specimens of a uterus from outside. Both light and polarizing microscopes were utilized to view them. Results: Different food particles and substances gave different appearances that could lead to misdiagnosis. Some of these also exhibited positive birefringence under the polarizing microscope. Conclusion: Knowledge and familiarity with probable foreign substances which can appear in tissues may help prevent misdiagnosis or erroneous diagnosis of biopsy specimens.
ABSTRACT
The aim of this vitro-study is to evaluate the effects of fluoride on remineralization of artificial dentine caries. 10 sound permanent premolars, which were extracted for orthodontic reason within 1 week, were used for this study. Artificial dentine caries was created by using a partially saturated buffer solution for 2 days with grounded thin specimens and fractured whole-body specimens. Remineralization solutions with three different fluoride concentration (1 ppm, 2 ppm and 4 ppm) were used on demineralized-specimens for 7 days. Polarizing microscope and scanning electron microscope were used for the evaluation of the mineral distribution profile and morphology of crystallites of hydroxyapatite. The results were as follows : 1. When treated with the fluoride solutions, the demineralized dentine specimens showed remineralization of the upper part and demineralization of the lower part of the lesion body simultaneously. 2. As the concentration of fluoride increased, the mineral precipitation in the caries dentine increased. The mineral precipitation mainly occurred in the surface layer in 1 and 2 ppm-specimens and in the whole lesion body in 4 ppm-specimens. 3. When treated with the fluoride solution, the hydroxyapatite crystals grew. This crystal growth was even observed in the lower part of the lesion body which had shown the loss of mineral.