Effects of in vivo exposure to GSM-modulated 900 MHz radiation on mouse peripheral lymphocytes

The aim of this study was to evaluate whether daily whole-body exposure to 900 MHz GSM-modulated radiation could affect spleen lymphocytes. C57BL/6 mice were exposed 2 h/day for 1, 2 or 4 weeks in a TEM cell to an SAR of 1 or 2 W/kg. Untreated and sham-exposed groups were also examined. At the end of the exposure, mice were killed humanely and spleen cells were collected. The number of spleen cells, the percentages of B and T cells, and the distribution of T-cell subpopulations (CD4 and CD8) were not altered by the exposure. T and B cells were also stimulated ex vivo using specific monoclonal antibodies or LPS to induce cell proliferation, cytokine production and expression of activation markers. The results did not show relevant differences in either T or B lymphocytes from mice exposed to an SAR of 1 or 2 W/kg and sham-exposed mice with few exceptions. After 1 week of exposure to 1 or 2 W/kg, an increase in IFN-gamma (Ifng) production was observed that was not evident when the exposure was prolonged to 2 or 4 weeks. This suggests that the immune system might have adapted to RF radiation as it does with other stressing agents. All together, our in vivo data indicate that the T- and B-cell compartments were not substantially affected by exposure to RF radiation and that a clinically relevant effect of RF radiation on the immune system is unlikely to occur.     

Dosimetry in mice exposed to 1.6 GHz microwaves in a carrousel irradiator

We have developed a carrousel irradiator for mice which delivers a head‐first and near‐field radiofrequency exposure that more closely simulates cellular telephone and radio use than conventional whole body exposure systems. Mouse cadavers were placed on the carrousel irradiator and exposed with their noses 5 mm from the feedpoint of a 1.6 GHz antenna. Local measured specific absorption rates (SAR) in brain regions corresponding to the frontal cortex, medial caudate putamen, and midhippocampal areas were 2.9, 2.4, and 2.2 W/kg per watt of irradiated power, respectively. In addition, average SAR was estimated to be 3.4 W/kg per watt along the sagittal plane of the brain, 2.0 W/kg per watt along the sagittal plane of the body, and between 6.8 and 8.1 W/kg per watt at peak locations along the sagittal plane at the body surface. This detailed SAR information in mice is critical to the interpretation of biological studies of IRIDIUM exposure, and similar analysis should be included for all studies of in vivo exposure of small animals to microwaves. Bioelectromagnetics 20:42–47, 1999. © 1999 Wiley‐Liss, Inc.     

Far-field dosimetric measurements in a full-sized man model at 2.0 GHz

Electromagnetic dosimetry was conducted in a tissue-equivalent full-sized model of man irradiated at 2 GHz inside a microwave-anechoic chamber. A nonperturbing temperature probe and a gradient-layer calorimeter were used to determine local and whole-body specific absorption rate (SAR), respectively. Relatively high SAR values were found in the limbs compared to the axis of the trunk of the model. The calorimeter experiments yielded an average SAR about three times higher than that estimated theoretically for a prolate spheroidal model of man. It is suggested that resonant interactions involving the limbs may be responsible for the disparity between theory and experiment.     

Radiofrequency dosimetry for the Ferris-wheel mouse exposure system

Numerical and experimental methods were employed to assess the individual and collective dosimetry of mice used in a bioassay on the exposure to pulsed radiofrequency energy at 900 MHz in the Ferris-wheel exposure system (Utteridge et al., Radiat. Res. 158, 357-364, 2002). Twin-well calorimetry was employed to measure the whole-body specific absorption rate (SAR) of mice for three body masses (23 g, 32 g and 36 g) to determine the lifetime exposure history of the mice used in the bioassay. Calorimetric measurements showed about 95% exposure efficiency and lifetime average whole-body SARs of 0.21, 0.86, 1.7 and 3.4 W kg(-1) for the four exposure groups. A larger statistical variation in SAR was observed in the smallest mice because they had the largest variation in posture inside the plastic restrainers. Infrared thermography provided SAR distributions over the sagittal plane of mouse cadavers. Thermograms typically showed SAR peaks in the abdomen, neck and head. The peak local SAR at these locations, determined by thermometric measurements, showed peak-to-average SAR ratios below 6:1, with typical values around 3:1. Results indicate that the Ferris wheel fulfills the requirement of providing a robust exposure setup, allowing uniform collective lifetime exposure of mice.     

Comparative evaluation of Pseudomonas fluorescens and their lipopolysaccharides as implicated in induction of resistance against pearl millet downy mildew

Two plant growth promoting Pseudomonas fluorescens isolates namely UOM SAR 14 and UOM SAR 80 most effectively induced resistance against downy mildew disease of pearl millet both under greenhouse and field conditions. Relative assessment of live cultures of P. fluorescens UOM SAR 14 and UOM SAR 80 and their lipopolysaccharides (LPS) extracted from their cell walls were evaluated for their ability to induce resistance against pearl millet downy mildew. Treatment with P. fluorescens and their LPS enhanced the seed germination and seedling vigour considerably. Although both live cultures and their LPS treatment induced resistance in pearl millet against downy mildew disease both under greenhouse and field conditions as evidenced by the significant reduction of the disease, live cultures were more effective than the LPS in level of resistance induced. Live cultures of UOM SAR 14 and UOM SAR 80 induced 66% and 57% protection while their respective LPS extracts offered 59 and 53% protection against downy mildew disease under greenhouse conditions. Similarly, under field conditions with very heavy inoculum pressure live cultures offered 75% and 70%, and their LPS offered 71% and 67% protection, respectively. In either case, the time gap required for the building up of resistance was found to be 3 days and nature of the resistance induced was systemic and durable with both live cultures and their lipopolysaccharides. It was also noticed that the live bacteria significantly varied in the degree of protection offered and so also their respective LPS.     

Dosimetry evaluation of a cylindrical waveguide chamber for unrestrained small rodents at 1.9 GHz

An exposure system, consisting of four identical cylindrical waveguide chambers, was developed for studying the effects of radiofrequency (RF) energy on laboratory mice at a frequency of 1.9 GHz. The chamber was characterized for RF dose rate as a function of animal body mass and dose rate variations due to animal movement in the cage. Dose rates were quantified in terms of whole‐body average (WBA) specific absorption rate (SAR), brain average (BA) SAR and peak spatial‐average (PSA) SAR using measurement and computational methods. Measurements were conducted on mouse cadavers in a multitude of possible postures and positions to evaluate the variations of WBA‐SAR and its upper and lower bounds, while computations utilizing the finite‐difference time‐domain method together with a heterogeneous mouse model were performed to determine variations in BA‐SAR and the ratio of PSA‐SAR to WBA‐SAR. Measured WBA‐SAR variations were found to be within the ranges of 9–23.5 W/kg and 5.2–13.8 W/kg per 1 W incident power for 20 and 40 g mice, respectively. Computed BA‐SAR variations were within the ranges of 3.2–10.1 W/kg and 3.3–9.2 W/kg per 1 W incident power for 25 and 30 g mouse models, respectively. Ratios of PSA‐SAR to WBA‐SAR, averaged over 0.5 mg and 5 mg tissue volumes, were observed to be within the ranges of 6–15 and 4–10, respectively. Bioelectromagnetics 33:575–584, 2012. © 2012 Wiley Periodicals, Inc.     

Decidual spiral artery remodeling during early post-implantation period in mice: investigation of associations with decidual uNK cells and invasive trophoblast

Circumferential remodeling of spiral arteries (SAs) during pregnancy is crucial for regulating maternal blood flow into the placenta and clinically important. However its mechanism is still ill defined in humans and mice. In mice, several important aspects of decidual SA remodeling (SAR) remain unexplored and were addressed here using morphometrics by examining SAs within the mesometrial half of the decidua basalis between embryonic day 6.5 (E6.5) and midgestation (E10.5). The data presented here provide evidence that supports the following novel conclusions about SAR: (a) SAs (defined by their muscular walls) appear between E6.5 and E7.5, undergo 'outward hypertrophic' SAR (SA lumen widening with muscular wall thickening) during the E7.5-E8.5 and E9.5-E10.5 periods, and 'outward hypotrophic' SAR (SA lumen widening with muscular wall thinning) during the E8.5-E9.5 interval. (b) 'Outward hypotrophic' SAR is associated with decreases in the overall number, but not density, of SA media nuclei, suggesting loss of SA muscular wall cells. Proximity of placenta-derived invasive trophoblast to SAs appears not be involved in SAR, as these cells were undetectable in the mesometrial region of decidua basalis throughout the E6.5-E10.5 period. Although the maternally derived lymphocytes of the decidual uterine natural killer (uNK) cell type are required for decidual SAR, the timing of this, the uNK cell parameter involved and the type of SAR they influence have not been adequately explored. Evidence is presented here that not all decidual SAR during this period is uNK cell-dependent. Rather, the data suggest that uNKs only influence 'outward hypotrophic' SAR during the E8.5-E9.5 period. Evidence is presented that the uNK cell parameter involved is the attainment of a certain maturation state (based on uNK cell size) by SA wall uNKs of the Dolichos biflorus agglutinin (DBA) lectin-positive uNK cell subset. This work also suggests that the previously shown loss of contractile mural cell character from the SA wall does not depend on either uNKs or trophoblast proximity. The novel implications of the present data for early mouse pregnancy are discussed.     

Far-field microwave dosimetry in a rhesus monkey model

Dosimetric measurements were made in a muscle-equivalent model of an adult rhesus monkey subjected to far-field irradiation at 1.29 GHz. Profiles of microwave-induced heating in the model were obtained at eight locations, and a gradient-layer whole-body calorimeter was used to measure total absorbed energy. Average specific absorption rate (SAR) was calculated both from the calorimeter experiments and from the local temperature measurements. Thermographic imaging techniques were used to qualitatively show the microwave-induced surface heating patterns. For this model the calculated average SAR was 0.155 (W/kg)/(mW/cm²) which, at 1.29 GHs, makes the absorption cross section 84% of the geometric shadow cross section. The SAR is about three times that predicted for a prolate spheroidal model of similar mass. A disproportionally high absorption occured in the legs of the model positioned parallel to the E-polarization because of what is believed to be partial-body resonance.     

Microwaves (2,450 MHz) suppress murine natural killer cell activity

The effect of 2,450-MHz CW microwaves on natural killer (NK) cell activity and lymphocyte responsiveness to mitogen stimulation was studied in mice. Groups of mice were irradiated at power densities of 5, 15, or 30 mW/cm2 (SAR = 3.5, 10.5, and 21 W/kg respectively) for 1.5 h on 2 or 9 consecutive days. NK cell activity was determined using an in vitro 51Cr release cytotoxicity assay and an in vivo tumor-cell clearance assay. No consistent change was observed in the mitogen response of spleen cells from sham compared with irradiated mice. A significant suppression of NK cell activity measured in vitro was observed for mice irradiated at 30 mW/cm2, but not at 15 or 5 mW/cm2. A significant suppression of NK cell activity, as determined using the in vivo tumor clearance assay, was also observed at 30 mW/cm2. NK cell activity, as determined using the in vitro assay, returned to normal within 24 h following the last irradiation. Treatment of mice with hydrocortisone caused suppression of NK cell activity measured in vitro and in vivo. Paradoxically, peritoneal macrophage phagocytosis was enhanced following irradiation at 30 mW/cm2, the power density at which NK activity was suppressed. The possible role that microwave heating plays in producing these effects is discussed.     

Impaired Ca2+ store functions in skeletal and cardiac muscle cells from sarcalumenin-deficient mice

Sarcalumenin (SAR), specifically expressed in striated muscle cells, is a Ca2+-binding protein localized in the sarcoplasmic reticulum (SR) of the intracellular Ca2+ store. By generating SAR-deficient mice, we herein examined its physiological role. The mutant mice were apparently normal in growth, health, and reproduction, indicating that SAR is not essential for fundamental muscle functions. SAR-deficient skeletal muscle carrying irregular SR ultrastructures retained normal force generation but showed slow relaxation phases after contractions. A weakened Ca2+ uptake activity was detected in the SR prepared from mutant muscle, indicating that SAR contributes to Ca2+ buffering in the SR lumen and also to the maintenance of Ca2+ pump proteins. Cardiac myocytes from SAR-deficient mice showed slow contraction and relaxation accompanied by impaired Ca2+ transients, and the mutant mice exhibited a number of impairments in cardiac performance as determined in electrocardiography, ventricular catheterization, and echocardiography. The results obtained demonstrate that SAR plays important roles in improving the Ca2+ handling functions of the SR in striated muscle.     

Effects of low level microwave radiation on carcinogenesis in Swiss Albino mice

This study concerns with the multiple treatment of the target site to potent carcinogen and the super imposition of low level radiofrequency and microwave radiation. Swiss albino mice (male) were used for this investigation. The study has been divided in two parts, part A: a single dose of 7,12-dimethylbenz(a)anthracene (DMBA) 100 μg/animal was applied topically on the skin of mice and were exposed to 112 MHz amplitude modulated (AM) at 16 Hz (power density 1.0 mW/cm(2), specific absorption rate (SAR) 0.75 W/kg). Similarly after a single dose of DMBA, mice were exposed to 2.45 GHz radiation (power density of 0.34 mW/cm(2), SAR, 0.1 W/kg), 2 h/day, 3 days a week for a period of 16 weeks. The two sets of experiments were carried out separately. Part B: mice were transplanted intraperitoneally (ip) with ascites 8 × 10(8) (Ehrlich-Lettre ascites, strain E) carcinoma cells per mouse. These mice were exposed to 112 MHz amplitude modulated at 16 Hz and 2.45 GHz radiation separately for a period of 14 days. There was no tumor development in mice exposed to RF and MW. Similarly a topical application of single dose of DMBA followed by RF/MW exposure also did not produce any visible extra tumor on the skin of mice. On the other hand mice were transplanted intraperitoneally with ascites (8 × 10(8) cell/ml) and subsequently exposed to above mentioned fields for 14 days showed a slight increase in the cell numbers as compared to the control group. However, the increase is insignificant. There were insignificant differences either in the mortality or cell proliferation among the control and exposed group. This results show that low level RF or MW do not alter tumor growth and development as evidenced by no observable change in tumor size.     

Dosimetric analysis of the carousel setup for the exposure of rats at 1.62 GHz

The so-called carousel setup has been widely utilized for testing the hypotheses of adverse health effects on the central nervous system (CNS) due to mobile phone exposures in the frequency bands 800-900 MHz. The objectives of this article were to analyze the suitability of the setup for the upper mobile frequency range, i.e., 1.4-2 GHz, and to conduct a detailed experimental and numerical dosimetry for the setup at the IRIDIUM frequency band of 1.62 GHz. The setup consists of a plastic base on which ten rats, restrained in radially positioned tubes, are exposed to the electromagnetic field emanating from a sleeved dipole antenna at the center. Latest generation miniaturized dosimetric E field and temperature probes were used to measure the specific absorption rate (SAR) inside the brain of three rat cadavers of the Lewis strain and two rat cadavers of the Fisher 344 strain. A numerical analysis was conducted on the basis of three numerical rat phantoms with voxel sizes between 1.5 and 0.125 mm3 that are based on high resolution MRI scans of a 300 g male Wistar rat and a 370 g male Sprague-Dawley rat. The average of the assessed SAR values in the brain was 2.8 mW/g per W antenna input power for adult rats with masses between 220 and 350 g and 5.3 mW/g per W antenna input power for a juvenile rat with a mass of 95 g. The strong increase of the SAR in the brain with decreasing animal size was verified by simulations of the absorption in numerical phantoms scaled to sizes between 100 and 500 g with three different scaling methods. The study also demonstrated that current rat phantom models do not provide sufficient spatial resolution to perform absolute SAR assessment for the brain tissue. The variation of the SAR(brain)(av) due to changes in position was assessed to be in the range from +15% to -30%. A study on the dependence of the performance of the carousel setup on the frequency revealed that efficiency, defined as SAR(brain)(av) per W antenna input power, and the ratio between SAR(brain)(av) and SAR(body)(av) are optimal in the mobile communications frequency range, i.e., 0.8-3 GHz.     

Synthesis and biological evaluation of 2-alkoxycarbonylallyl esters as potential anticancer agents

The reaction of carboxylic acids with Baylis-Hillman reaction derived α-bromomethyl acrylic esters readily provide 2-(alkoxycarbonyl)allyl esters in good to excellent yields. These functionalized allyl esters have been evaluated for their cell proliferation inhibition properties against breast cancer (MDA-MB-231 and 4T1) and pancreatic cancer (MIAPaCa-2) cell lines to explore their potential as anticancer agents. Several of the synthesized derivatives exhibit good potency against all three cancer cell lines. Our structure activity relationship (SAR) studies on 2-carboxycarbonyl allyl esters indicate that substituted aromatic carboxylic acids provide enhanced activity compared to substituted aliphatic carboxylic acid analogs. Di- and tri-allyl esters derived from di-and tri-carboxylic acids exhibit higher inhibition of cell proliferation than mono esters. Further SAR studies indicate that the double bond in the 2-(alkoxycarbonyl)allyl ester is required for its activity, and there is no increase in activity with increased chain length of the alkoxy group. Two lead candidate compounds have been identified from the cell proliferation inhibition studies and their preliminary mechanism of action as DNA damaging agents has been evaluated using epifluorescence and western blot analysis. One of the lead compounds has been further evaluated for its systemic toxicity in healthy CD-1 mice followed by anticancer efficacy in a triple negative breast cancer MDA-MB-231 xenograft model in NOD-SCID mice. These two in vivo studies indicate that the lead compound is well tolerated in healthy CD-1 mice and exhibits good tumor growth inhibition compared to breast cancer drug doxorubicin.     

Effects of long-term storage at -14 degrees C on the survival of Neozygites fresenii (Entomophthorales: Neozygitaceae) in cotton aphids (Homoptera: Aphididae)

Neozygites fresenii-infected Aphis gossypii cadavers, containing dormant hyphal bodies of N. fresenii, were stored in 4 ml glass vials at -14 degrees C in a standard consumer-type refrigerator/freezer for 1, 21, 30, 43, 51, and 68 months to determine the effect of storage on fungal survival. When the cadavers were removed from the freezer and placed in 25+/-1 degrees C, 100% relative humidity, and 12:12 (L:D) conditions, N. fresenii survival, as shown by fungal sporulation from the cadavers, was high at all storage periods. The average percentage of cadavers from which the fungus sporulated were 93, 47, 100, 100, 80, and 60% from 1, 21, 30, 43, 51, and 68 months storage periods, respectively. The number of primary conidia discharged from each sporulating cadaver was estimated using a scale of 1 (low, ca. 1000 primary conidia), 2 (medium, ca. 2000 primary conidia) and 3 (high, ca. 3000 primary conidia). The median scores for the number of primary conidia produced per sporulating cadaver were 3, 2, 3, 3, 2.5, and 1 for 1, 21, 30, 43, 51, and 68 months, respectively. Therefore, except for the longest storage period, most cadavers produced medium to high numbers of primary conidia. Mean germination of primary conidia produced from N. fresenii-infected-aphid cadavers from each time period varied significantly from 66.3 to 86.1% in the 21 and 43 months categories, respectively. Infectivity of capilliconidia, produced from frozen N. fresenii, to live healthy cotton aphids varied significantly from 16.7 to 68.7% from cadavers stored 68 months and 1 month, respectively. Overall N. fresenii survived well in dried frozen cotton aphid cadavers for up to 6 years with little reduction in sporulation, numbers of spores produced, germination of primary conidia, or infectivity.     

Chemokine-independent preference for T-helper-1 cells in transendothelial migration

We analyzed differences in the transendothelial migration (TEM) ability of T-helper (Th)-1 and Th2 cells across a murine endothelial cell line (F-2) under static conditions. The TEM abilities of Th1 cells from mice bearing autoimmune diseases and antigen-specific Th1 cell lines were severalfold higher than those of Th2 cells and lines of the same origin. These preferences were observed without exogenous chemoattractant and were insensitive to pertussis toxin, which completely blocks TEM induced by exogenous chemoattractants. Antibodies against LFA-1 and ICAM-1 as well as CD44 markedly blocked the TEM of Th1 cells. TEM ability was also blocked by pharmacological inhibitors of Src family protein-tyrosine kinases (PP2 and herbimycin A), phosphatidylinositol 3-kinase (wortmannin), and phosphatidylinositol-specific phospholipase C (). Cross-linking of CD44 strongly induced highly elongated morphology in Th1 lines, but weakly in Th2 lines. The pharmacological inhibitors that blocked TEM also inhibited this morphological change, whereas pertussis toxin did not. These data indicate that there are signaling pathways for TEM independent of chemokine attraction, but through adhesion molecules including CD44, and that the preferential TEM ability of Th1 over Th2 cells is formed, at least in part, by intrinsic differences in these pathways.     

Significant Differences in the Development of Acquired Resistance to the MDM2 Inhibitor SAR405838 between In Vitro and In Vivo Drug Treatment

SAR405838 is a potent and specific MDM2 inhibitor currently being evaluated in Phase I clinical trials for the treatment of human cancer. Using the SJSA-1 osteosarcoma cell line which harbors an amplified MDM2 gene and wild-type p53, we have investigated the acquired resistance mechanisms both in vitro and in vivo to SAR405838. Treatment of SJSA-1 cells with SAR405838 in vitro leads to dose-dependent cell growth inhibition, cell cycle arrest and robust apoptosis. However, prolonged treatment of SJSA-1 cells in vitro with SAR405838 results in profound acquired resistance to the drug. Analysis of in vitro-derived resistant cell lines showed that p53 is mutated in the DNA binding domain and can no longer be activated by SAR405838. Treatment of the parental SJSA-1 xenograft tumors with SAR405838 in mice yields rapid tumor regression but the tumors eventually regrow. Culturing the regrown tumors established a number of sublines, which showed only modest (3–5 times) loss of sensitivity to SAR405838 in vitro. Sequencing of the p53 showed that it retains its wild-type status in these in vivo sublines, with the exception of one subline, which harbors a single heterozygous C176F p53 mutation. Using xenograft models of two in vivo derived sublines, which has either wild-type p53 or p53 containing a single heterozygous C176F mutation, we showed that while SAR405838 effectively achieves partial tumor regression in these models, it no longer induces complete tumor regression and tumors resume growth once the treatment is stopped. Harvesting and culturing tumors obtained from a prolonged treatment with SAR405838 in mice established additional in vivo sublines, which all contain a single heterozygous C176F mutation with no additional p53 mutation detected. Interestingly, SAR405838 can still effectively activate p53 in all sublines containing a single heterozygous C176F mutation, with a moderately reduced potency as compared to that in the parental cell line. Consistently, SAR405838 is 3–5 times less effective in all the in vivo derived sublines containing a single heterozygous C176F p53 mutation than in the SJSA-1 parental cell line in assays of cell growth and apoptosis. Computational modeling suggested that a p53 tetramer containing two wild-type p53 molecules and two C176F mutated molecules can maintain the structural stability and interactions with DNA by formation of additional hydrophobic and cation-π interactions which compensate for the loss of sulphur-zinc coordination. Our data thus show that SJSA-1 tumor cells acquire very different levels of resistance in vitro and in vivo to the MDM2 inhibitor SAR405838. Our present study may have a significant implication for the investigation of resistant mechanisms for other classes of anticancer drugs.     

Delayed hypersensitivity in murine salmonellosis: specificity of footpad reaction in mice infected with rough mutants of Salmonella typhimurium

Delayed type (footpad) hypersensitivity (DTH) in BALB/c mice immunized with rough mutant strains of Salmonella typhimurium LT2 was examined. Injection of live organisms of an Rb mutant TV148 strain induced DTH in mice, while injection of the heat-killed organisms did not. The mice immunized with live organisms of the Ra, Rb, Rc, Rd, and Re mutant strains showed positive footpad reactions to the heat-killed cell antigen of LT2 (wild type) strain. The mice immunized with the Rb mutant strain also showed positive footpad swellings in response to heat-killed cell antigens of S. paratyphi A, S. paratyphi B, S. typhi, S. enteritidis, and S. cholerae-suis. Furthermore, positive reactions to antigens of Escherichia coli and Shigella flexneri were seen in the TV148-immunized mice, but the mice did not respond to heat-killed organisms of Pseudomonas aeruginosa or Staphylococcus aureus. The cross-reactive footpad reaction to E. coli could be transferred adoptively with T cells prepared from the spleens of TV148-immunized mice into syngeneic recipients. These results suggest that the cross-reactive DTH antigen(s) is widely distributed among related organisms such as Shigella and Escherichia.     

Visualizing spatiotemporal dynamics of multicellular cell-cycle progression

The cell-cycle transition from G1 to S phase has been difficult to visualize. We have harnessed antiphase oscillating proteins that mark cell-cycle transitions in order to develop genetically encoded fluorescent probes for this purpose. These probes effectively label individual G1 phase nuclei red and those in S/G2/M phases green. We were able to generate cultured cells and transgenic mice constitutively expressing the cell-cycle probes, in which every cell nucleus exhibits either red or green fluorescence. We performed time-lapse imaging to explore the spatiotemporal patterns of cell-cycle dynamics during the epithelial-mesenchymal transition of cultured cells, the migration and differentiation of neural progenitors in brain slices, and the development of tumors across blood vessels in live mice. These mice and cell lines will serve as model systems permitting unprecedented spatial and temporal resolution to help us better understand how the cell cycle is coordinated with various biological events.     

Effect of the meniscus at the solid/liquid interface on the SAR distribution in Petri dishes and flasks

Several authors have reported that the meniscus as occurring at the walls of Petri dishes and flasks (solid-liquid interface) can significantly affect the SAR distribution in the entire dish and flask, while others have ignored this effect. In this study, this effect has been comprehensively analyzed by numerical means supported by theoretical considerations. The focus is on E polarization, which results in the most homogeneous exposure for monolayer cell cultures and therefore is the most often applied polarization in exposure setups for risk assessment studies. This includes setups based on TEM cells, waveguides, radial transmission lines (RTL), and HF chambers. The conclusion of this study is that the meniscus and its size have a significant effect on the strength and homogeneity of the induced SAR distribution. Hence, the meniscus needs to be accounted for in the determination of the averaged SAR as well as in the uncertainty assessment. It has also been demonstrated that a voxel size of less than 0.2 mm is needed to predict the SAR values for a monolayer of cells accurately.     

Studies on the IgA-independent immunological responses in mice to influenza virus challenge after oral vaccination with irradiated whole virus and an erythrocyte complex

Previous studies have described an oral influenza vaccine comprising whole irradiated virus and an erythrocyte complex (IV-EC), which gave broad-based protection against influenza virus challenge in mice. The present study examined the immune responses generated after live virus challenge of vaccinated mice, particularly to determine whether mice vaccinated with IV-EC had enhanced CTL activity to compensate for the previously reported diminution in lung IgA response. Oral vaccine groups examined were IV-EC, live virus alone (LV) or live virus-erythrocyte complex (LV-EC), compared with irradiated virus and erythrocyte alone controls. The antibody responses of IV-EC and LV-EC vaccinated mice showed significantly elevated lung and serum IgG2a levels post live virus challenge, with no comparable increases in IgG1 levels compared to controls. Spleen cells from IV-EC mice showed an enhanced post-challenge proliferative response to antigen compared with mice that had received live oral vaccines, indicating enhanced cellular activity post IV-EC immunization. However, CTL activity was not enhanced for IV-EC mice, and live virus-vaccinated mice had reduced CTL activity compared with controls, indicating that CTL were not important for post-vaccine protection. Cytokine analysis revealed a predominant IFN-gamma response in spleen cells from orally vaccinated mice, whereas IL-4 was not detected in any lung or spleen culture analysed. The results suggest, therefore, that protection from live influenza challenge after IV-EC or LV-EC vaccination was due to an IFN-mediated IgG2a response. Definitive confirmation of the role of these factors in post-vaccine protection can now be tested in IgG2a-depleted or IFN-gamma gene knockout mouse models.