Arsenic uptake and accumulation in fern species growing at arsenic-contaminated sites of southern China: field surveys

Aiming at searching for new arsenic (As) hyperaccumulators, field surveys were conducted at 12 As-contaminated sites located in Guangxi and Guangdong Provinces of southern China. Samples of 24 fern species belonging to 16 genera and 11 families as well as their associated soils were collected and As concentrations in plant and soil samples were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results show that among 24 fern species, Pteris multifida and P. oshimensis can (hyper)accumulate As in their fronds with high concentrations in addition to P. vittata and P. cretica var. nervosa, which have been previously identified as As hyperaccumulators. Total As concentrations in soils associated with P. multifida and P. oshimensis varied from 1262 to 47,235 mg kg(-1), but the DTPA-extractable As concentrations were relatively low, with a maximum of 65 mg kg(-1). Forty-four of 49 samples of P. multifida collected from five sites and 3 of 13 samples of P. oshimensis collected from one site accumulated over 1000 mg As kg(-1) in their fronds and As concentrations in the fronds were higher than those in the petioles and rhizoids. Although As concentrations in the fronds of P. oshimensis (789 mg kg(-1) averaged, range 301-2142 mg kg(-1)) were comparatively lower than those of P. multifida (1977 mg kg9-1), 624-4056 mg kg(-1)), its high aboveground biomass makes it more suitable for phytoremediating As-contaminated soils. Among all the species in Pteris genus studied, Pteris semipinnata accumulated only very low As concentration in its fronds (8 mg kg(-1), 1-18 mg kg(-1)). Further research is needed to study the differences in As uptake and accumulation among fern species in the same or other genera.

Cloned piglets born after nuclear transplantation of embryonic blastomeres into porcine oocytes matured in vivo

Nuclear transplantation in the pig is more difficult than in other domestic animals and only one embryonic nuclear transplantation (NT) pig has been born to date. In this study, reconstituted porcine embryos were produced by electrofusion of blastomeres from in vivo four-cell embryos to enucleated in vivo or in vitro matured (IVM) oocytes. Nuclear transfer using cumulus cells as nuclear donors was also conducted. When blastomeres were used as donors, the electrofusion rate was significantly higher in oocytes matured in vivo (91.5%) than in those matured in vitro (66.1%) (p < 0.01). After fusion, the NT embryos reconstituted from in vivo matured oocytes developed to blastocysts at a rate of 10.3% after culture in rabbit oviducts for up to 5 days, while only 5.9% of the NT embryos reconstructed from in vitro matured oocytes developed to blastocyst stage. Electrofusion rate of cumulus cell nuclei with enucleated IVM oocytes was lower (47.6%) and only 1.5% (2/136) of the reconstituted eggs developed in vitro to morula stage, and 1.9% developed to blastocysts when cultured in the ligated rabbit oviducts. Transfer of 94 embryos reconstructed by blastomere NT with in vivo matured oocytes to five synchronous recipients resulted in the birth of two cloned piglets. No piglet was born following transfer to two recipients of embryos (n = 39) derived from NT with in vitro matured oocytes. The results demonstrate that in vivo matured oocytes are better recipients than those matured in vitro for pig cloning.

Macroscopic quantum tunneling in a d-wave high-TC Bi2Sr2CaCu2O8 + delta superconductor

While Josephson-junction-like structures intrinsic to the layered cuprate high temperature superconductors offer an attractive stage for exploiting possible applications to new quantum technologies, the low energy quasiparticle excitations characteristically present in these d-wave superconductors may easily destroy the coherence required. Here we demonstrate for the first time the feasibility of macroscopic quantum tunneling in the intrinsic Josephson junctions of a high temperature superconductor Bi(2)Sr(2)CaCu(2)O(8 + delta), and find it to be characterized by a high classic-to-quantum crossover temperature and a relatively weak quasiparticle dissipation.

Maximum entropy image deconvolution applied to structure determination for crystal Nd1.85Ce0.15CuO4−δ

Eight [100] images from a through-focus series of tetragonal crystal Nd1.85Ce0.15CuO4-delta were transformed separately into the structure images by means of maximum entropy image deconvolution. The constructed projected structure model based on the deconvoluted image is confirmed by image simulation. It is demonstrated that the image deconvolution is still successful even when some reflections fall in the vicinity of zero cross of contrast transfer function. The effectiveness and advantages of the technique are discussed.

Increased calbindin-D28k immunoreactivity in striatal projection neurons of R6/2 Huntington's disease transgenic mice

Striatal degeneration in Huntington's disease (HD) is associated with increases in perikaryal calbindin immunolabeling in yet-surviving striatal projection neurons. Since similar increases have also been observed in surviving striatal projection neurons after intrastriatal injection of the excitotoxin quinolinic acid, the increased calbindin in HD striatum has been interpreted to suggest an excitotoxic process in HD. We used immunolabeling to assess if calbindin is elevated in striatal projection neurons of R6/2 HD transgenic mice. These mice bear exon 1 of the human huntingtin gene with 144 CAG repeats and show some of the neuropathological signs (e.g., neuronal intranuclear inclusions) and clinical traits (e.g., wasting prior to early death) of HD. We found an increased frequency of calbindin-immunoreactive neuronal perikarya in the striatum of 6- and 12-week-old R6/2 mice compared to wild-type controls. This increase was most notable in the normally calbindin-poor dorsolateral striatum. We found no significant changes in the total area of striatum occupied by the calbindin-negative striosomes and no consistent changes in striatal calbindin mRNA. The increase in calbindin in R6/2 striatal neurons was thus limited to the matrix compartment, and it may be triggered by increased Ca2+ entry due to the demonstrated heightened NMDA sensitivity of these neurons. The data further support the similarity of R6/2 mice to HD, and are consistent with the occurrence of an excitotoxic process in striatum in both.

The distribution and cellular localization of glutamic acid decarboxylase-65 (GAD65) mRNA in the forebrain and midbrain of domestic chick

The distribution and cellular localization of GAD65 mRNA in the forebrain and midbrain of domestic chick were examined by in situ hybridization histochemistry with (35)[S]-UTP labeled cRNA probes, using film and emulsion autoradiography. Film autoradiograms showed intense GAD65 labeling in many structures of the basal telencephalon, such as the medial and lateral striatum, the septum, the olfactory tubercle, the lateral bed nucleus of the stria terminalis, and the intrapeduncular nucleus, while the pallial telencephalon showed only a low level of labeling. Emulsion-coated sections revealed that GAD65 mRNA-containing neurons were at least six times more abundant in striatum than pallium, with only a uniformly scattered subpopulation labeled in pallium, and that the vast majority of the large scattered projection neurons of globus pallidus were heavily labeled for GAD65. Prominent labeling was also evident in the nucleus taeniae and subpallial amygdala, but not in the arcopallium in film autoradiograms. Within the diencephalon, the hypothalamus was more GAD65-rich than the thalamus. Additional subtelencephalic cell groups showing prominent labeling included the thalamic reticular nucleus and ventral lateral geniculate nucleus of the diencephalon, the nucleus pretectalis, subpretectalis and spiriformis lateralis of the pretectum, and the magnocellular isthmic nucleus of the optic lobe. Tectal layers 9-10 were also rich in GAD65. These results further clarify GABAergic circuits of the avian forebrain and midbrain, and show them to closely resemble those in mammals.

Lead in paddy soils and rice plants and its potential health risk around Lechang lead/zinc mine, Guangdong, China

As part of a project on phytoextraction of lead (Pb) in paddy soils around a lead/zinc (Pb/Zn) Mine in Lechang of Guangdong Province, South China, the concentration distribution of Pb in paddy soil-rice system was investigated, and its potential health risk to animal/human was evaluated. Total and diethylenetetraminepentaacetic acid (DTPA)-extractable Pb in soils averaged 1486 and 268 microg/g, respectively. According to sequential extraction procedure, soil Pb occurred primarily in the residual, carbonate and exchangeable fractions (30.2%, 26.7% and 19.1%, respectively). Lead extracted by the gastric juice simulation test (GJST) was 1068 microg/g and accounted for 75.4% of the total concentration. Mean Pb concentrations of 419 microg/g in rice root, 69.1 microg/g in whole straw, 51.0 microg/g in part straw (without two leaves near above the root), 44.9 microg/g in stalk, 21.9 microg/g in hull, 13.2 microg/g in grain with hull and 4.67microg/g in grain without hull (namely, unpolished rice) were found. Lead concentrations in both soil and rice plant were far above the corresponding tolerable levels. Lead daily intakes by local residents were 2.6 mg for adults and 1.2 mg for children, which were much higher than the allowable level. Thus, Pb in this area might pose a potential health risk to the local population.

Bone mass and lifestyle related factors: a comparative study between Japanese and Inner Mongolian young premenopausal women

The purpose of this study was to evaluate the ethnic difference in bone mass between Japanese and Inner Mongolian young premenopausal women and to assess the contribution of lifestyle related and anthropometric factors to bone mass. We studied 33 Japanese and 44 Inner Mongolian healthy young women, aged 20-34 years, in urban area. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) were measured at the calcaneus using quantitative ultrasound (QUS) analysis. Age at menarche, regularity of menstruation and lifestyle related factors were estimated by a self-reported questionnaire. There were no differences between the two groups in age, height, weight, BMI, regularity of menstruation, frequency of meat intake, frequency of yellow-green vegetable intake and exercise habit. Japanese women had significantly lower age at menarche and higher proportion of milk consumption habit at junior high school, senior school and present. Before adjustment, Japanese women had significantly higher SOS and SI than Inner Mongolian women. However, after adjustment for age at menarche and milk consumption habit at junior high school, both of which were significantly different between groups, no group-differences remained in either SOS or SI. These results suggest that the differences in age at menarche and milk consumption habit at junior high school, which relate to hormonal and nutritional status during puberty, may account for the differences in bone mass between Japanese and Inner Mongolian young women.

A further discussion on the peculiarity of maximum entropy image deconvolution in HREM

Some important features observed in the maximum entropy image deconvolution in HREM were studied and demonstrated as a supplement to previous publications in Ultramicroscopy 35 (1991) 339 and 62 (1996) 141. It has been shown that in the process of image deconvolution how the errors of assigned electron-optical parameters can be compensated and the effect of crystal thickness can be corrected. The 'negative-potential problem' has been solved more perfectly than before via the normalization of sum total entropy.

Effects of taurine supplementation on VDT work induced visual stress

In order to evaluate the effects of dietary taurine supplementation on visual fatigue induced by visual display terminals (VDT) work, 25 male college students aged from 20 to 24 years who were not engaged in VDT work were selected to participate in the study. Volunteers were randomly assigned to either the taurine supplementation (n=13) or the placebo supplementation control group (n=12). Before and after 12 days of taurine (3 g/day) or placebo supplementation, two identical 2.5-hr VDT work tests were performed while recording the P100, N75 and N145 latencies and P100 amplitude of pattern visual evoked potential (PVEP) and the frequency of critical flicker fusion (CFF). Following 2.5-hr of VDT work, the P100 and N75 latencies of PVEP increased ( P<0.01) while the P100 amplitude decreased significantly ( P<0.01). The frequency of CFF also reduced significantly ( P<0.01). After 12 days of taurine supplementation, the reduction in P100 amplitude after VDT work alleviated significantly ( P<0.05). The results suggest that taurine supplementation alleviates visual fatigue induced by VDT work.

Field and temperature induced magnetic transition in Gd5Sn4: a giant magnetocaloric material

Gd5Sn4 exhibits a giant magnetocaloric effect comparable to that reported in the Gd5(Si,Ge)(4) system. The giant magnetocaloric effect is associated with a first-order change that occurs at approximately 82 K in zero field, and can be reversed by the application of an external field of a few Tesla. 119Sn Mössbauer spectroscopy shows that this material is magnetically inhomogeneous over a wide range of temperatures and fields.

A study on the position of boron atoms in (Y(0.6)Ca(0.4))(SrBa)(Cu(2.5)B(0.5))O(7-delta)

The position of boron atoms in minute crystals of (Y(0.6)Ca(0.4))(SrBa)(Cu(2.5)B(0.5))O(7-delta) was studied by means of image processing based on the combination of high-resolution electron microscopy and electron diffraction. The structure image was obtained from a single image by image deconvolution based on the principle of maximum entropy. Its resolution is limited by that of the electron microscope. Then the image resolution was enhanced to about 1 A by direct-methods phase extension in combination with an empirical method of electron diffraction intensity correction. To study the substitution of boron atoms for copper, in the second cycle of diffraction intensity correction two different structure models were proposed. The one corresponding to a more reasonable atomic shape in the derived projected potential map (PPM) was accepted. In this model, the boron atoms are located at the 'chain' Cu sites.

Increased expression of survivin in gastric cancer patients and in first degree relatives

Survivin was recently described as an apoptosis inhibitor. Its pathogenic role in gastric cancer is largely unknown. Expression of survivin in gastric cancer and non-cancer first-degree relatives, and its association with apoptosis and cyclo-oxygenase-2 expression was investigated. Fifty gastric cancer, 30 non-cancer first-degree relatives, 20 normal controls and five gastric cancer cell lines were studied. Survivin and cyclo-oxygenase-2 were evaluated by reverse transcriptase-polymerase chain reaction, immunohistochemistry and Western blot. Survivin expression was absent from normal gastric mucosa. All five cancer cell lines and 34 out of 50 (68%) human gastric cancer tissues expressed survivin mRNA. Survivin expression was less frequent (22%; P<0.001) in adjacent non-tumour gastric tissues. Immunohistochemistry and Western blot obtained similar findings. Gastric cancers with survivin expression displayed significantly reduced apoptosis (P=0.02), and associated with cyclo-oxygenase-2 overexpression at both mRNA (P=0.001) and protein levels (P=0.041). Moreover, survivin mRNA was detected in the gastric mucosa of eight (27%) non-cancer relatives. Expression in non-cancer patients showed positive correlation with H. pylori infection (P=0.004). This demonstrates the frequent expression of survivin in gastric cancer and in first-degree relatives. Co-expression of survivin and cyclo-oxygenase-2 may suggest multiple pathways contributing to the inhibition of apoptosis in gastric cancer.

Genetic toxicity of a standardized mixture of citrus polymethoxylated flavones

Flavonoids are a ubiquitous family of phytochemicals that display a variety of biological effects, both beneficial and adverse depending on the individual compound. Certain flavonoids are genotoxic while others inhibit the genotoxicity of other mutagens. In the present studies, the mutagenicity of a mixture of polymethoxylated flavones (PMFs) purified from citrus peel oil was evaluated. The mixture consisted of nobiletin (32.5%), 3,3',4',5,6,7,8-heptamethoxyflavone (25.0%), tangeretin (14.0%), trimethylscutellarein (9.1%), sinensetin (3.9%), 5-demethyl-nobiletin (2.8%), hexa-O-methylquercetagetin (3.3%), 5-demethyl-tetramethylscutellarein (0.7%), 5-hydroxy-3,3',4',6,7,8-hexamethoxyflavone (0.7%), and a small quantity of unidentified flavonoid compounds (3.9%). In vitro addition of the PMF mixture over a concentration range that spanned four log doses (0.0005-5.0 mg/plate) did not reveal any evidence of mutagenicity in five bacterial tester strains (Salmonella typhimurium TA98, TA100, TA102, TA1535 and TA1537) either in the absence or presence of S9 activation. The PMF mixture exhibited a statistically significant increase in mutagenicity of L5178Y tk(+/-) mouse lymphoma cells at 0.05 (38.5 x 10(-6); P<0.05) and 0.1 mg/ml (61 x 10(-6); P<0.01) compared with vehicle-treated controls (mutation frequency=19.7 x 10(-6)). However, these responses were within historical values observed in negative control cultures and extremely small compared to the positive control (EMS 0.5 microl/ml; 1685.3 x 10(-6)). Furthermore, in the presence of S9 there was no indication of genetic toxicity in L5178Y tk(+/-) cells. These results demonstrate that the PMF mixture is not genotoxic in in vitro assay systems.

[The human alpha(2A)-AR gene and the genotype of site -1296 and the susceptibility to motion sickness]

The gene sequences of alpha(2A)-adrenergic receptor(alpha(2A)-AR) in 39 Chinese and 1 Englishman showed 13 differences of g or c insertion or deletion in its regulation region, coding region and 3' untranslated region, compared with that reported in GenBank. The gene sequences from all the samples respectively were identical except for 2 single nucleotide polymorphisms, including the sequence of sense and antisense strand sequenced. It was found that: (1) the frequency of gg genotype in Chinese and Japanese, who are high susceptible to motion sickness, were 5.8 and 7.8 fold higher than that in Englishmen; (2) g allele frequencies in Chinese and Japanese were higher than latter ( P 0.01 ); (3) gg genotype frequency in population susceptible to motion sickness was 1.6 fold higher than that in population unsusceptible to motion sickness, and g allele frequency was higher than latter ( P 0.01 ). All the populations were in Hardy-Weinberg equilibrium. The results suggested that gg genotype and g allele at site -1296 in alpha(2A)-AR gene could associate with the susceptibility to motion sickness.

[Non-linear compression for noises in non-contact vital signs detecting system]

A method for compressing the noises overlapping in the breath and heart signals of human beings, detected by the non-contact vital signs detecting system during the display of the waveforms in time domain, is discussed in this paper in detail. And what's more, the problem that the noise level is changed along with the increase of the gain of AD data-acquisition card and the display--gain of the software is solved by researching into the threshold of noise-level contraction in two types of circumstance in the lab, and the result of the breath and heart signal in the condition of lower noise is realized as well.

Biosynthetic pathway to the cancer chemopreventive secoisolariciresinol diglucoside-hydroxymethyl glutaryl ester-linked lignan oligomers in flax (Linum usitatissimum) seed

Application of stable and radioisotope precursor/tracer experiments resulted in the identification of various phenylpropanoid, monolignol, and lignan metabolites involved in the biosynthesis of the cancer chemopreventive secoisolariciresinol diglucoside (SDG; 1)-containing ester-linked "polymer(s)" in flax (Linum usitatissimum) seed. Individual analysis of size-segregated flax seed capsules at five early stages of their development provided a metabolic profile of intermediates leading to "biopolymer" biosynthesis. The use of (1)H and (13)C NMR and HRMS analyses resulted in the identification of 6a-HMG (hydroxymethyl glutaryl) SDG (17) and 6a,6a'-di-HMG SDG (18) as the two major components of the ester-linked "biopolymer(s)". Based on metabolic tracer analyses and relative radioisotopic incorporations throughout each of these five stages of seed development, a biochemical pathway is proposed from phenylalanine to SDG (1), with subsequent mono- and di-substitutions of SDG (1) with HMG CoA. These metabolites then serve as precursors for formation of the SDG-HMG ester-linked oligomers. Results from this study will facilitate future isolation and characterization of the proteins and enzymes involved in biosynthesis of the SDG-HMG ester-linked oligomers in flax seed.

Immunotoxicity of a standardized citrus polymethoxylated flavone extract

Polymethoxylated flavones (PMFs) from citrus inhibit production of TNF-alpha and other pro-inflammatory cytokines. As TNF-alpha also modulates NK cell activity, the current studies were conducted to assess the potential for a standardized citrus PMF mixture to suppress humoral and innate immune functions. PMFs were isolated from orange peel oil using a procedure that obtained a consistent mixture of PMFs both in identity and proportion. The mixture consisted of nobiletin (30.7%), 3,3',4',5,6,7,8-heptamethoxyflavone (27.9%), trimethylscutellarein (14.5%), tangeretin (10.4%), sinensetin (5.8%), 5-demethyl-nobiletin (2.0%), hexa-O-methylquercetagetin (1.3%), 5-demethyl-tetramethylscutellarein (0.6%), and other flavonoids (2.7%). To assess the effect of the PMF mixture on humoral immune responses, female B(6)C(3)F(1) mice (n=8) were exposed to the PMF by gavage at 5, 50, 150 and 500 mg/kg/day for 28 days. On day 25, mice were sensitized to sRBC by tail vein injection and AFC response determined 4 days later. Humoral immunity was insensitive to suppression following exposure to all concentrations of the PMF mixture. Suppression of NK cell activity was observed only following 500 mg/kg/day for 28 days. Body weights were not affected by exposure to any concentration of the PMF mixture in sRBC immunized or non-immunized mice. However, in sRBC-immunized mice, higher concentrations of PMF were associated with a statistically insignificant increase in spleen weight (P>0.05). No change in spleen weight was observed in non-immunized mice. As anticipated, based on previously published in vitro observations, long-term, high-dose exposure to a standardized mixture of citrus PMFs caused a mild suppression of NK cell activity; however, humoral immunity was not sensitive to suppression at the same exposure levels.

Focal adhesion kinase is involved in mechanosensing during fibroblast migration

Focal adhesion kinase (FAK) is a non-receptor protein tyrosine kinase localized at focal adhesions and is believed to mediate adhesion-stimulated effects. Although ablation of FAK impairs cell movement, it is not clear whether FAK might be involved in the guidance of cell migration, a role consistent with its putative regulatory function. We have transfected FAK-null fibroblasts with FAK gene under the control of the tetracycline repression system. Cells were cultured on flexible polyacrylamide substrates for the detection of traction forces and the application of mechanical stimulation. Compared with control cells expressing wild-type FAK, FAK-null cells showed a decrease in migration speed and directional persistence. In addition, whereas FAK-expressing cells responded to exerted forces by reorienting their movements and forming prominent focal adhesions, FAK-null cells failed to show such responses. Furthermore, FAK-null cells showed impaired responses to decreases in substrate flexibility, which causes control cells to generate weaker traction forces and migrate away from soft substrates. Cells expressing Y397F FAK, which cannot be phosphorylated at a key tyrosine site, showed similar defects in migration pattern and force-induced reorientation as did FAK-null cells. However, other aspects of F397-FAK cells, including the responses to substrate flexibility and the amplification of focal adhesions upon mechanical stimulation, were similar to that of control cells. Our results suggest that FAK plays an important role in the response of migrating cells to mechanical input. In addition, phosphorylation at Tyr-397 is required for some, but not all, of the functions of FAK in cell migration.

Terahertz responses of intrinsic Josephson junctions in high T(c) superconductors

High frequency responses of intrinsic Josephson junctions up to 2.5 THz, including the observation of Shapiro steps under various conditions, are reported and discussed in this Letter. The sample was an array of intrinsic Josephson junctions singled out from inside a high T(C) superconducting Bi2Sr2CaCu2O(8+x) single crystal, with a bow-tie antenna integrated to it. The number of junctions in the array was controllable, the junctions were homogeneous, the distribution of applied irradiation among the junctions was even, and the junctions could synchronously respond to high frequency irradiation.

Mi2, an auto-antigen for dermatomyositis, is an ATP-dependent nucleosome remodeling factor

Dynamic changes in chromatin structure play an important role in transcription regulation. Recent studies have revealed two mechanisms that alter chromatin structure. One involves ATP-dependent chromatin remodeling, and the other involves acetylation of the core histone tails. We have previously purified and characterized a multi-subunit protein complex, NuRD, which possesses both nucleosome remodeling and histone deacetylase activities. Despite extensive biochemical characterization of the complex, little is known about the functions of its individual components. In this study, we focused on Mi2, a component of the NuRD complex. We found that, similar to the native NuRD complex, recombinant Mi2 is a DNA-dependent, nucleosome-stimulated ATPase. Kinetic analysis of the ATP hydrolysis reaction indicated that the differential stimulation of the Mi2 ATPase by DNA and nucleosomes were primarily due to their differential effects on the turnover number of the reaction. Furthermore, we demonstrated that recombinant Mi2 is an efficient nucleosome remodeling factor when compared to that of the native NuRD complex. Our results define the biochemical function of Mi2 and set the stage for understanding the mechanism of nucleosome remodeling in a defined reconstituted system.

Anti-CTLA-4 antibody treatment triggers determinant spreading and enhances murine myasthenia gravis

CTLA-4 appears to be a negative regulator of T cell activation and is implicated in T cell-mediated autoimmune diseases. Experimental autoimmune myasthenia gravis (EAMG), induced by immunization of C57BL/6 mice with acetylcholine receptor (AChR) in adjuvant, is an autoantibody-mediated disease model for human myasthenia gravis (MG). The production of anti-AChR Abs in MG and EAMG is T cell dependent. In the present study, we demonstrate that anti-CTLA-4 Ab treatment enhances T cell responses to AChR, increases anti-AChR Ab production, and provokes a rapid onset and severe EAMG. To address possible mechanisms underlying the enhanced autoreactive T cell responses after anti-CTLA-4 Ab treatment, mice were immunized with the immunodominant peptide alpha(146-162) representing an extracellular sequence of the ACHR: Anti-CTLA-4 Ab, but not control Ab, treatment subsequent to peptide immunization results in clinical EAMG with diversification of the autoantibody repertoire as well as enhanced T cell proliferation against not only the immunizing alpha(146-162) peptide, but also against other subdominant epitopes. Thus, treatment with anti-CTLA-4 Ab appears to induce determinant spreading, diversify the autoantibody repertoire, and enhance B cell-mediated autoimmune disease in this murine model of MG.

[The study on non-contact detection of breathing and heartbeat based on radar principles]

The paper introduces the design of hardware and software of non-contact detection system for breathing and heartbeat in human body with radar principles and technology. The detection technology is discussed. Under conditions of the illuminating power P < 1 mW and the distance S < 10 m, the non-contact breathing and heartbeat measurement, can be in different positions and with different clothing on the subject. The results show that the system with the technology has a high sensitivity, and is harmless to the health. It is a practicable non-contact detection technology for breathing and heartbeat of human body.

Comparison of the viscoelastic properties of normal hepatocytes and hepatocellular carcinoma cells under cytoskeletal perturbation

The viscoelastic properties of both hepatocytes and hepatocellular carcinoma (HCC) cells were measured by means of a micropipette aspiration technique. Experimental results were analyzed with a three-element standard linear solid model, in which an elastic element, K1, is in parallel with a Maxwell element composed of another elastic element, K2, in series with a viscous element, mu. Further, we investigated the relevance of viscoelastic properties of these two types of cells to the cytoskeleton structures by treating cells with three cytoskeletal perturbing agents, namely cytochalasin D (CD), colchicine (Col) and vinblastine (VBL). The results showed that the elastic coefficients, but not viscous coefficient of HCC cells (K1 = 103.6 +/- 12.6 N m-2, K2 = 42.5 +/- 10.4 N m-2, mu = 4.5 +/- 1.9 Pa s, n = 30), were significantly higher than the corresponding values for hepatocytes (K1 = 87.5 +/- 12.1 N m-2, K2 = 33.3 +/- 10.3 N m-2, mu = 5.9 +/- 3.0 Pa s, n = 24). Upon treatment with CD, the viscoelastic coefficients of both hepatocytes and HCC cells decreased uniformly, with magnitudes for the decrease in elastic coefficients of HCC cells (K1: 68.7 to 81.7 N m-2, 66.3 to 78.9%; K2: 34.5 to 37.1 N m-2, 81.2 to 87.3%) larger than those for normal hepatocytes (K1: 42.6 to 49.8 N m-2, 48.7 to 56.9%; K2: 17.2 to 20.4 N m-2, 51.7 to 61.3%). There was a smaller decrease in the viscous coefficient of HCC cells (2.0 to 3.4 Pa s, 44.4 to 75.6%) than that for hepatocytes (3.0 to 3.9 Pa s, 50.8 to 66.1%). Upon treatment with Col and VBL, the elastic coefficients of hepatocytes generally increased or tended to increase while those of HCC cells decreased. The differences in either the pattern or the magnitude of the effect of cytoskeletal perturbing agent on the viscoelastic properties between HCC cells and hepatocytes might possibly reflect differences in the state of the cytoskeleton structure and function, or in the cells' sensitivity to perturbing agent treatment between these two types of cells. Changes in the viscoelastic properties of cancer cells might well affect tumor cell invasion and metastasis as well as interactions between tumor cells and their micro-mechanical environments.