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While hyperthermia has been shown to induce a variety of cytotoxic and sensitizing effects on cancer tissues, the thermal dose–effect relationship is still not well quantified, and it is still unclear how it can be optimally combined with other treatment modalities. Additionally, it is speculated that different methods of applying hyperthermia, such as water bath heating or electromagnetic energy, may have an effect on the resulting biological mechanisms involved in cell death or in sensitizing tumor cells to other oncological treatments. In order to further quantify and characterize hyperthermia treatments on a cellular level, in vitro experiments shifted towards the use of 3D cell spheroids. These are in fact considered a more representative model of the cell environment when compared to 2D cell cultures. In order to perform radiofrequency (RF)-induced heating in vitro, we have recently developed a dedicated electromagnetic field applicator. In this study, using this applicator, we designed and validated an experimental setup which can heat 3D cell spheroids in a conical polypropylene vial, thus providing a reliable instrument for investigating hyperthermia effects at the cellular scale. [ABSTRACT FROM AUTHOR]

Copyright of Tianjin Medical Journal is the property of Tianjin Medical Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article details a study which examined the cryopreservation of A72(dog), CRFK(cat), NB324K(human), MCF7(human), WI38(human), and C636(mosquito) cells using serum free crypreservative. The viability of cells stored in a frozen state while attached to substratum of 25 cm2 culture flasks for 30 to 180 days at -80°C is demonstrated. Study authors claim that their technique provides significant time and cost savings in laboratories that rapidly process numerous cell lines.

The article focuses on a study which explored two aspects of cryopreserving culture mammalian cells during routine laboratory maintenance. The study made use of a serum-free cryopreservative which was proven to be nearly as efficient as the serum-containing preservatives. It also compared cryostage of those cells in suspended versus a pellet form using both techniques.

Background: It has been demonstrated that human cultured epithelial sheets prepared by tissue engineering techniques provide useful graft material for wound healing and tissue regeneration. However, limited information is available with regard to biological effects such as release of growth factors from human cultured gingival epithelial sheets (HCGES). The purpose of this study was to measure the levels of growth factors released from HCGES into culture medium Methods: Twenty patients aged 44 to 71 years with generalized chronic periodontitis were recruited, and their gingival tissues obtained during periodontal flap surgery. The levels of vascular endothelial growth factor (VEGF), transforming growth factor-α and -βl (TGF-α and -βl), and epidermal growth factor (EGF) released into the culture medium were determined using enzyme-linked immunosorbent assay at the just confluent (Tl) and the adequate stratification (T2) culture stages. The medium without cells was collected as a control (TO) statistical tests were performed by analysis of variance and sheffé multiple range test among TO, T1, and T2.Results: Significantly higher levels of VEGF and TGF-α were observed at T1 and T2 compared to To (P<0.001). In addition, there was a significant difference in the TGF-α levels between T2 and T1 (P<0.001). TGF-βl at T1 was significantly higher in comparison to T0 (P<0.0l). EGF had been released only in a small amount at T2.Conclusion: This study indicates that meaningful amounts of VEGF and TGF-α and -βl are released from HCGES, which suggests potential for promoting wound healing and tissue regeneration after grafting. J Periodontol 2002;73:748-753. [ABSTRACT FROM AUTHOR]

Background: Enamel matrix derivative (EMD) contains a variety of hydrophobic enamel matrix proteins and is extracted from developing embryonal enamel of porcine origin. EMD has been associated with the formation of acellular cementum and it has been found to stimulate periodontal regeneration. The present study was established to investigate the influence of EMD on human periodontal ligament (PDL) cells, gingival fibroblasts (GF), and osteosarcoma (MG-63) cells on wound-fill rates using an in vitro wound model.Methods: Wounds were created by making 3 mm incisions in cell monolayers across the length of tissue culture plates. The wounded PDL, GF, and MG-63 cell monolayers were treated with media containing EMD over a concentration range of 5 to 100 microg/ml, platelet-derived growth factor (PDGF-BB) at 20 ng/ml as a positive control and insulin-like growth factor (IGF-I) at 100 ng/ml as a negative control. PDL cell wounded monolayers also were treated in EMD coated tissue culture plates. After an incubation period (up to 9 days), the cells were fixed and stained and cellular fill was measured across the width of the wound by computer-assisted histomorphometry.Results: When PDL, GF, and MG-63 cells were exposed to EMD in culture medium, an enhanced wound-fill was observed for all cells compared to untreated conditions. At early time points, PDL wound-fill rates in the presence of EMD were statistically greater than the rates of GF and MG-63 treated with EMD (P<0.001). There were no significant differences in wound-fill rates of PDL cells treated with EMD in medium versus EMD coated on culture plates. At days 3 and 6 post-wounding, PDL cells showed a significantly greater response to EMD than to PDGF-BB (P <0.001). EMD also had a greater effect on GF wound-fill rates than PDGF-BB at days 6 and 9. MG-63 cells were less responsive to PDGF-BB and EMD than PDL cells and GF. All 3 cell types treated with IGF-I showed no significant increase of wound-fill rates.Conclusion: The present data support the concept that clinical application of enamel matrix derivative may enhance periodontal wound regeneration by specifically modifying periodontal ligament cell proliferation and migration. [ABSTRACT FROM AUTHOR]

Background: A well-characterized cell culture model for cementoblasts is essential to understand the mechanisms of periodontal ligament (PDL) reattachment and regeneration. Whether cementoblasts express alkaline phosphatase (ALP) activity in vivo and in vitro remains to be determined. Methods: Using a 2-step method of enzyme digestion/ explant culture, osteoblasts, gingival/PDL fibroblasts, and cementoblasts were obtained from alveolar bone, gingiva, and the root surface of rat first molars and cultured. Initially, bone sialoprotein (BSP) was immunolocalized on tissue sections of periodontium and on cultured cells to distinguish mineral-forming cells from fibroblasts. Proteins were extracted from these cells to assess ALP activity by using an enzyme assay. RMA was extracted from the same cell source to detect ALP mRNA by reverse transcriptase polymerase chain reaction (RT-PCR). Results: Cultured PDL/gingiva) fibroblasts were spindle shaped. Osteoblasts were irregularly shaped, and cell clusters/nodules were observed as they approached confluence. The cementoblasts manifested a polygonal shape and had two morphotypes: osteoblast-like and cuboidal or stratified. BSP was localized within the mineralized tissues and in osteoblasts and cemento blasts in culture and in tissue sections. The highest level of ALP activity was found in osteoblasts, a moderate level in PDL fibroblasts, and the lowest level in gingival fibroblasts. The cementoblasts lacked ALP activity, and this was reflected by a very weak signal (or no signal at all) for ALP mRNA in the cementoblasts. Conclusions: These studies indicate that cells consistent with a cementoblast-like phenotype may be successfully cultured, and that they lack ALP activity. [ABSTRACT FROM AUTHOR]

Routinely grown cell suspension cultures of Mucuna pruriens L. (Fabaceae) were able to endogenously accumulate the anti-Parkinson drug L-dihydroxyphenylalanine (L-dopa) in the range between 0.2 and 2% on a dry weight (DW) basis. The green colour that developed in light-exposed cultures, appeared to be a suitable marker to select cells with an increased L-dopa biosynthesis and/or phenoloxidase activity. For this purpose, saccharose concentrations from 0 to 4% (w/v), and light intensities of 1,000 and 2,000 lux, were involved in the selection procedure. After 6 months, photomixotrophic callus cultures with a rapid growth and a high L-dopa content of 0.9% (DW) were obtained on 2% saccharose and under 1,000 lux. The cell suspensions, derived from these calli, accumulated up to 6% (DW) L-dopa, which was the highest stable content ever measured in cultures of M. pruriens. An L-dopa yield of approximately 1.2 g/l was calculated after 6 days of growth. In contrast, compared with the standard-grown parent cell line, the phenoloxidase activity, and consequently the bioconversion capacity as measured after entrapment in calcium alginate, of these high-producing cultures was approximately threefold lower. [ABSTRACT FROM AUTHOR]

Callus and root organ cultures of Coreopsis tinctoria and C. lanceolata have been established in liquid nutrition medium. Their capacity to accumulate unusual phenylpropanoids was compared with that of seedlings and whole plants. Corresponding callus cultures accumulated the phenylpropanoids only in traces. In contrast to the unorganized callus cultures the root organ cultures accumulated the same pattern of phenylpropanoids as their parent plants. A root organ culture of C. tinctoria accumulated the compounds up to the same amounts as the root of the whole plant. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Cancer Research & Clinical Oncology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A simple procedure for the rapid preparation of virus isolates from cell culture for negative-contrast electron microscopy was devised. Using only conventional centrifugation steps (i.e. without ultracentrifugation), the procedure produced consistent, fine-quality preparations of a variety of virus types differing in size/shape and buoyant density. [ABSTRACT FROM AUTHOR]

The possible influence of gold(III) chloride and the two gold(I)-containing anti-arthritic drugs, auranofin and sodium aurothiomalate, on cellular ploidity and cell cycle progression was investigated on cultured human epithelial cells. Four different cell lines were used: the parent line (HE) and three sub-strains which previously had acquired resistance to the antiproliferative effects of either 350 μmol gold chloride/1 culture medium (HE), 2 μmol auranofin/1 (HE) or 300 μmol sodium aurothiomalate/1 (HE). DNA-histograms were obtained by flow cytometry examinations during a 9-days' exposure to either of these gold-containing compounds and concentrations. The HE, HE and HE cells had similar ploidities, close to tetraploid. The HE cells had altered ploidity to distinct tetraploid. The distribution of the resistant cells with the cell cycle phases was not different from that of untreated HE cells. The HE cells, when treated with auranofin or sodium aurothiomalate, accumulated in the G-phase of the cell cycle. In addition, a new cedecoploid peak appeared. No such changes were observed on gold chloride exposure or in HE controls grown without drug supplement. The effects of auranofin and sodium aurothiomalate on cell cycle progression of the HE cells possibly indicate a tendency to polyploidity, and furthermore that inhibition of cellular mitosis is one mechanism of the antiproliferative effect common to the two drugs. [ABSTRACT FROM AUTHOR]

Immunosurgical isolation of inner cell masses (ICMs) from sheep embryos was most efficient at the expanded, zona-intact blastocyst stage (day 7 to 8 post oestrus) before migration of endoderm cells beyond the boundary of the ICM across the blastocoelic surface of the trophectoderm. When cultured under conditions which allow the isolation of embryonal stem (ES) cell lines from mouse ICMs, sheep ICMs attached, spread and developed areas of both ES cell-like and endoderm-like cells. After prolonged culture only endoderm-like cells were evident. The implications for the isolation of ES cell lines from sheep embryos and possible species-specific requirements are discussed. [ABSTRACT FROM AUTHOR]

In conclusion the use of an in vitro cell culture system proved to be very valuable for (partly) elucidating the way of action of absorption-enhancing compounds and for the investigation of critical factors associated with absorption enhancement. The use of isolated cell culture systems like the Caco-2 cells can also have some drawbacks. Although this cell line is considered to be a very adequate model for intestinal epithelium, its properties might in some respects not be the same as those of normal cells, due to the fact that the cell line, originating from a carcinoma, consists of transformed cells. Direct extrapolation of potentially useful methods from the in vitro to the in vivo situation remains an important issue to consider as well and has been shown to be hazardous in the current investigations. A principal reason for this may be associated with the problem of maintaining conditions in vivo very similar to those investigated in vitro. [ABSTRACT FROM AUTHOR]