ObjectiveTo investigate the bioeffects of extremely low frequency (ELF) magnetic field (MF) (50 Hz, 400μT) and magnetic nanoparticles (MNPs) via cytotoxicity and apoptosis assays on PC12 cells.
MethodsMNPs modified by SiO2 (MNP-SiO2) were characterized by transmission electron microscopy (TEM), dynamic light scattering and hysteresis loop measurement.PC12 cells were administrated with MNP-SiO2 with or without MF exposure for 48 h. Cytotoxicity and apoptosis were evaluated with MTT assay and annexin V-FITC/PI staining, respectively. The morphology and uptake of MNP-SiO2 were determined by TEM. MF simulation was performed by Ansoft Maxwell based on the finite element method.
ResultsMNP-SiO2 were identified as~20nm (diameter) ferromagnetic particles. MNP-SiO2reduced cell viability in a dose-dependent manner. MF also reduced cell viability with increasing concentrations of MNP-SiO2. MNP-SiO2 alone did not cause apoptosis in PC12 cells; instead, the proportion of apoptotic cells increased significantly under MF exposure and increasing doses of MNP-SiO2. MNP-SiO2 could be ingested andthen cause a slight change in cellmorphology.
ConclusionCombined exposure of MF and MNP-SiO2 resulted in remarkable cytotoxicity and increased apoptosis in PC12 cells. The results suggested that MF exposure couldstrengthen the MF of MNPs, which may enhance the bioeffects of ELF MF.

A brachial plexus injury model was established in rabbits by stretching the C6 nerve root. Imme-diately after the stretching, a suspension of human amniotic epithelial cells was injected into the injured brachial plexus. The results of tensile mechanical testing of the brachial plexus showed that the tensile elastic limit strain, elastic limit stress, maximum stress, and maximum strain of the injured brachial plexuses were signiifcantly increased at 24 weeks after the injection. The treat-ment clearly improved the pathological morphology of the injured brachial plexus nerve, as seen by hematoxylin eosin staining, and the functions of the rabbit forepaw were restored. These data indicate that the injection of human amniotic epithelial cells contributed to the repair of brachial plexus injury, and that this technique may transform into current clinical treatment strategies.

Astrocytes are specialized and most numerous glial cell type in the central nervous system and play important roles in physiology. Astrocytes are also critically involved in many neural disor-ders including focal ischemic stroke, a leading cause of brain injury and human death. One of the prominent pathological features of focal ischemic stroke is reactive astrogliosis and glial scar for-mation associated with morphological changes and proliferation. This review paper discusses the recent advances in spatial and temporal dynamics of morphology and proliferation of reactive astrocytes after ischemic stroke based on results from experimental animal studies. As reactive astrocytes exhibit stem cell-like properties, knowledge of dynamics of reactive astrocytes and glial scar formation will provide important insights for astrocyte-based cell therapy in stroke.

The quantity and survival time of astrocytes, which were differentiated from adult adipose-derived stromal cells after exposure to an inducer containing 3-isobutyl-1-methylxanthine, have thus far been unsatisfactory. The present study investigated the growth and differentiation characteristics of induced astrocytes by observing their growth curves. After induction for 48 hours with an inducer containing 0.5% ethanol, some adult adult adipose-derived stromal cells displayed typical astrocytic morphology. The cell quantity gradually decreased with prolonged induction time. Nestin, glial fibrillary acidic protein, and S-100 expression reached peak levels at 14 days, but neuron-specific enolase was not expressed. These results suggest that the induced astrocytes reached their peak at 14 days. Further optimization of the culture environment may yield mature astrocytes with normal functions, in greater quantity, and prolonged survival time.

The waltzing guinea pig may be a good model to investigate if genetic factor can change the sensitivity in noise-induced hearing loss. A total of 34 waltzig guinea pigs were studied and we found that there is no any significant increased sensitivity to noise trauma if the age-induced hearing loss was considered in waltz-ing guinea pig.

兔耳增生性瘢痕的形态学观察与羟脯氨酸含量变化

Objective To establish animal model for hypertreophic scar and study the characteristics of its morphology and collagen metabolism.Methods A total of 64 wounds(diameter of 6 mm each ) with total skin loss were made on the ventral side of rabbit ear using a trephine. Morphology and collagen metabolism of scar wound were studied at 14,21,35,70 and 98 days after operation,respectively.Results There were 76% elevated scars developed (45/59 wounds) on the ventral side of rabbit ear on 21st and 35 days.The number of fibroblast decreased,but irregular-arranged fibers still presented in the elevated scars at 70 and 98 days after operation. Hydroxyproline content in elevated scars at 21 days was higher than that in normal skin(P< 0.05),and at 35 days was 3 times as that in normal skin and at 98 days was also markedly higher than that in normal skin(P< 0.05).Conclusion Excessive deposition of collagen is a characteristic of hypertrophic scar in rabbits. The conversion of normal scarring to hypertrophic scarring in rabbits occurs at 14～ 21 days after operation. Both development and regression of hypertrophic scar in rabbit are quicker than that in human.

Objective:The aim of our study was to observe the survival and morphological changes of thawed ovarian tis-sues after heterotopic transplantation. Methods:Twenty SPF-SD female rats (5-6 weeks old) were equal y randomized into the control group and experimental group. In control group, the freshly isolated ovaries were fixed in formalin. In experimental group, the freshly isolated ovaries were vitrified immediately and cut into thin slices. After stored in liquid nitrogen for 21 days, the tissues of experimental group were rapidly thawed and transplanted into back muscles of rats for 2 or 4 weeks, respectively. After that, al rats in experimental group were sacrificed and the ovarian tissues were col ected and fixed in 4%formaldehyde solution. Then the ovarian tissues were stained with HE and observed under the light confocal microscope. Re-sults:With the naked eyes, there was no specific alteration except the size reduction with color changing. Under microscopy, we found normal cortex and medul a in the ovary, and the primordial fol icles and fol icles in various stages were observed in the cortex. The normal oocytes in ovarian tissues of experimental group were significant decreased than in the control group. Conclusion:The ovarian tissues survive wel in experimental group and there is no significant dif erence in the proportion of fol icles between dif erent times (2 and 4 weeks) after grafting. Our results suggest that thawed ovarian tissues could survive after heterotopic transplantation into back muscles of rat models and maintain their morphology and function.

Colorectal cancer (CRC) results from the progressive accumulation of genetic and epigenetic alterations that lead to the transformation of normal colonic mucosa to adenocarcinoma. Approximately 75% of CRCs are sporadic and occur in people without genetic predisposition or family history of CRC. During the past two decades, sporadic CRCs were classiifed into three major groups according to frequently altered/mutated genes. These genes have been identiifed by linkage analyses of cancer-prone families and by individual mutation analyses of candidate genes selected on the basis of functional data. In the ifrst half of this review, we describe the genetic pathways of sporadic CRCs and their clinicopathologic features. Recently, large-scale genome analyses have detected many infrequently mutated genes as well as a small number of frequently mutated genes. These infrequently mutated genes are likely described in a lim-ited number of pathways. Gene-oriented models of CRC progression are being replaced by pathway-oriented models. In the second half of this review, we summarize the present knowledge of this research ifeld and discuss its prospects.

In Vitro Study on Lethal Effect of Human Choroidal Melanoma OCM-1 Cell Line by Repeating-70℃Freeze Thawing

Objective: To investigate the effects of repeating -70℃ freeze thawing on human choroidal melanoma cell line OCM-1.Methods: OCM-1 cells were frozen by repeating -70℃ freeze thawing with various durations and frequencies. Then the inhibit rate of cells was examined by MTT essay.The cell viability was measured by monoclonal formation assay. We also used the HE staining, immunohistochemistry staining and the laser-scanning confocal microscopy (LSCM) to investigate the morphological changes of the cells.Results: The growth of OCM-1 cells was inhibited by repeating -70℃ freeze thawing in time-dependent and frequency-dependent manners (P ＜ 0.01). Different morphous including necrosis and apoptosis of the cells could be observed after -70℃ freeze thawing by the LSCM.Conclusion: Repeating -70℃ freeze thawing can not only kill cells directly and induce considerable cells to apoptosis, but also inhibit the growth of the survivals. The kill and wound ratio of the cells disposal with different times and frequencies present variance. And the distinction when treated with different frequencies during the same time is much more significant than different times with the same frequency, which guide clinical workers to choose repeating cryotherapy with short term method instead of single cryotherapy with long term in choroidal melanoma treatment.

Investigation of charge-transfer (CT) complexes of drugs has been recognized as an important phenomenon in understanding of the drug-receptor binding mechanism. Structural, thermal, morpholo-gical and biological behavior of CT complexes formed between drug quinidine (Qui) as a donor and quinol (QL), picric acid (PA) or dichlorodicyanobenzoquinone (DDQ) as acceptors were reported. The newly synthesized CT complexes have been spectroscopically characterized via elemental analysis;infrared (IR), Raman, 1H NMR and electronic absorption spectroscopy; powder X-ray diffraction (PXRD);thermogravimetric (TG) analysis and scanning electron microscopy (SEM). It was found that the obtained complexes are nanoscale, semi-crystalline particles, thermally stable and spontaneous. The molecular composition of the obtained complexes was determined using spectrophotometric titration method and was found to be 1:1 ratios (donor:acceptor). Finally, the biological activities of the obtained CT complexes were tested for their antibacterial activities. The results obtained herein are satisfactory for estimation of drug Qui in the pharmaceutical form.