[Influences of high-voltage electrical burns on microcirculation perfusion on serosal surface of small intestine of rats and the interventional effects of pentoxifylline]

Objective: To investigate influences of high-voltage electrical burns on microcirculation perfusion on serosal surface of small intestine of rats and the interventional effects of pentoxifylline (PTX). Methods: Totally 180 SD rats were divided into sham injury group, simple electrical burn group, and treatment group according to the random number table, with 60 rats in each group. The electrical current was applied to the outside proximal part of left forelimb of rats and exited from the outside proximal part of right hind limb of rats. Rats in simple electrical burn group and treatment group were inflicted with high-voltage electrical burn wounds of 1cm×1cm at current entrances and exits, with the voltage regulator and experimental transformer. Rats in sham injury group were sham injured through connecting the same equipments without electricity. At 2 min post injury, rats in sham injury group and simple electrical burn group were intraperitoneally injected with 2 mL normal saline, and rats in treatment group were injected with 2 mL PTX injection (50 mg/mL). At 15 min before injury and 5 min, 1 h, 2 h, 4 h, and 8 h post injury, 10 rats in each group were selected to collect blood of heart respectively. Serum were separated from the blood to determine the level of soluble vascular cell adhesion molecule-1(sVCAM-1) with enzyme-linked immunosorbent assay method. The number of adhesional leukocyte in mesenteric venule of rats was determined with Bradford variable projection microscope system. The microcirculation perfusion on serosal surface of small intestine of rats was detected with laser Doppler perfusion imager. Data were processed with analysis of variance of factorial design and LSD test. Results: (1) At 5 min, 1 h, 2 h, 4 h, 8 h post injury, the serum content of sVCAM-1 in rats of simple electrical burn group were (8 502±1 158), (11 793±3 310), (9 960±2 146), (9 708±1 429), (7 292±1 386) ng/mL respectively, higher than that in sham injury group and treatment group [ (1 897±946), (1 882±940), (1 882±938), (1 888±946), (1 884±942) ng/mL, and (6 840±1 558), (6 742±2 465), (5 625±2 593), (2 373±1 463), (5 187±2 797) ng/mL, respectively, with P values below 0.001]. The serum content of sVCAM-1 in rats of sham injury group and treatment group at all time points post injury, except 4 h post injury of treatment group, was higher than that of the same group at 15 min before injury (with P values below 0.001). (2) At all time points post injury, the number of adhesional leukocyte in mesenteric venule of rats in simple electrical burn group was higher than that in sham injury group and treatment group (with P values below 0.001). The number of adhesional leukocyte in mesenteric venule of rats in simple electrical burn group and treatment group at all time points post injury was higher than that of the same group at 15 min before injury (with P values below 0.001). (3) At all time points post injury, the microcirculation perfusion on serosal surface of small intestine of rats in simple electrical burn group was lower than that in sham injury group and treatment group (with P values below 0.001). The microcirculation perfusion on serosal surface of small intestine of rats in simple electrical burn group and treatment group at all time points post injury was lower than that of the same group at 15 min before injury (with P values below 0.001). Conclusions: High-voltage electrical burns can increase the serum content of sVCAM-1, the number of adhesional leukocyte in mesenteric venule, and reduce microcirculation perfusion on serosal surface of small intestine of rats. PTX can inhibit secretion of serum sVCAM-1, reduce the number of adhensional leukocyte in mesenteric venule to alleviate microcirculation disturbance caused by high-voltage electrical burns.

Charge-Dependent Directed Flow in Cu+Au Collisions at sqrt[s_{NN}]=200 GeV

We present the first measurement of charge-dependent directed flow in Cu+Au collisions at sqrt[s_{NN}]=200  GeV. The results are presented as a function of the particle transverse momentum and pseudorapidity for different centralities. A finite difference between the directed flow of positive and negative charged particles is observed that qualitatively agrees with the expectations from the effects of the initial strong electric field between two colliding ions with different nuclear charges. The measured difference in directed flow is much smaller than that obtained from the parton-hadron-string-dynamics model, which suggests that most of the electric charges, i.e., quarks and antiquarks, have not yet been created during the lifetime of the strong electric field, which is of the order of, or less than, 1  fm/c.

Wnt7b gene expression and functional analysis in the mussel Mytilus coruscus

To understand the potential functions of Wnt7b in different developmental stages and adult tissues of the mussel Mytilus coruscus, the Wnt7b gene was cloned using the rapid amplification of cDNA ends technique. The full-length Wnt7b gene was 1910 bp long, with a 1059-bp open reading frame encoding 352 amino acids. The amino acid sequence of the M. coruscus Wnt7b gene shared high homology with that of Homo sapiens (59%), Mus musculus (61%), Danio rerio (61% similarity), Biomphalaria glabrata (62% similarity), Aplysia californica (66% similarity), and Crassostrea gigas (74%). Wnt7b mRNA expression was detected by reverse transcription PCR in all tissues studied (mantle, adductor muscle, gill, foot, digestive gland, and male and female gonads), with the highest expression found in the gill, and in the male and female gonads. This indicates that Wnt7b may play an important role in gonadal maturation and in the functions of gills in the mussel M. coruscus. Expression of the Wnt7b gene during larval development stages, including the trochophore, D-shaped veliger, umbo veliger, pediveliger, and juvenile stages, was also detected. Wnt7b mRNA was highly expressed in the D-shaped veliger, umbo veliger, and pediveliger larvae stages, suggesting that Wnt7b may participate in larval development and in the process of metamorphosis in the mussel M. coruscus. Taken together, these findings provide new insights into the functions of the Wnt gene family during mussel larval development and settlement and metamorphosis.

Measurement of the Transverse Single-Spin Asymmetry in p^{↑}+p→W^{±}/Z^{0} at RHIC

We present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at sqrt[s]=500  GeV by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse-momentum-dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. These data provide the first experimental investigation of the nonuniversality of the Sivers function, fundamental to our understanding of QCD.

Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC

We present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au+Au collisions for energies ranging from sqrt[s_{NN}]=7.7 to 200 GeV. The third harmonic v_{3}^{2}{2}=⟨cos3(ϕ_{1}-ϕ_{2})⟩, where ϕ_{1}-ϕ_{2} is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs Δη=η_{1}-η_{2}. Nonzero v_{3}^{2}{2} is directly related to the previously observed large-Δη narrow-Δϕ ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity quark gluon plasma phase. For sufficiently central collisions, v_{3}^{2}{2} persist down to an energy of 7.7 GeV, suggesting that quark gluon plasma may be created even in these low energy collisions. In peripheral collisions at these low energies, however, v_{3}^{2}{2} is consistent with zero. When scaled by the pseudorapidity density of charged-particle multiplicity per participating nucleon pair, v_{3}^{2}{2} for central collisions shows a minimum near sqrt[s_{NN}]=20  GeV.

Centrality and Transverse Momentum Dependence of Elliptic Flow of Multistrange Hadrons and ϕ Meson in Au+Au Collisions at √[sNN]=200 GeV

We present high precision measurements of elliptic flow near midrapidity (|y|<1.0) for multistrange hadrons and ϕ meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy √[sNN]=200  GeV. We observe that the transverse momentum dependence of ϕ and Ω v2 is similar to that of π and p, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0%-30% and 30%-80% collision centrality. There is an indication of the breakdown of previously observed mass ordering between ϕ and proton v2 at low transverse momentum in the 0%-30% centrality range, possibly indicating late hadronic interactions affecting the proton v2.

Observation of Transverse Spin-Dependent Azimuthal Correlations of Charged Pion Pairs in p^{↑}+p at sqrt[s]=200 GeV

We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p^{↑}+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of 5 standard deviations at high transverse momenta, at high pseudorapidities η>0.5, and for pair masses around the mass of the ρ meson. This is the first direct transversity measurement in p+p collisions.

Azimuthal Anisotropy in U+U and Au+Au Collisions at RHIC

Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v_{2}{2} and v_{2}{4}, for charged hadrons from U+U collisions at sqrt[s_{NN}]=193  GeV and Au+Au collisions at sqrt[s_{NN}]=200  GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v_{2}{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. We also show that v_{2} vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

Triptolide inhibits the multidrug resistance in prostate cancer cells via the downregulation of MDR1 expression

Triptolide (TPL) is a diterpenoid triepoxide derived from the Chinese herb Tripterygium wilfordii and possesses anti-tumor activity against a range of cancer cells. However, the effect of TPL on prostate cancer cells and its potential to overcome multidrug resistance (MDR) have not been explored. Therefore, in this study we used prostate cancer cell line DU145 as the experimental model and established DU145/ADM cell line resistant to adriamycin (ADM). Our results showed that TPL inhibited the proliferation and induced the cell cycle arrest and apoptosis of DU145 cells in a dose and time dependent manner. TPL decreased the levels of Cyclin D1 and anti-apoptotic protein Bcl-2, and increased the levels of pro-apoptotic proteins Fas and Bax. Furthermore, we found that TPL restored the sensitivity DU145/ADM cells to ADM in a dose dependent manner, and this was accompanied by the inhibition of MDR1 expression at both mRNA and protein levels. Taken together, these results provide strong evidence that TPL overcomes MDR in prostate cancer cells by downregulating MDR1 expression, and suggest that TPL is a promising agent for prostate cancer therapy, especially for chemoresistant prostate cancer.

GATA-3 is down-regulated in patients with clear cell renal carcinoma

BACKGROUND

GATA-3 is a transcription factor involved in human growth and development. Recent studies found its association with breast cancer, however, its expression profile in renal cell carcinoma (RCC) has not been investigated.

MATERIAL AND METHOD

The study included 35 patients submitted to radical nephrectomy with confirmed pathological diagnosis of RCC. Normal control kidney tissues were obtained from 25 living kidney donors and tissues were biopsied before implantation. The majority of RCC samples were diagnosed as clear cell renal cell carcinoma (94.3%) except for 1 case of papillary RCC and 1 case of collecting duct carcinoma. GATA-3 expression was evaluated by quantitative PCR and Western blotting (WB) in RCC samples and normal kidneys respectively, immunohistochemical staining was performed as well. Meanwhile, the GATA-3 expression in two cancer cell lines (786-O, ACHN) and normal kidney epithelial cells (HK-2) was detected by PCR and WB. In addition, renal cancer cells and HK-2 cells were cultivated and detected by confocal microscopy for the exact intra-cellular localization of GATA-3.

RESULTS

Data showed a significant down-regulation of GATA-3 expression present in neoplastic tissues compared with normal tissues; similarly, GATA-3 was significantly attenuated in all renal cancer cell lines compared with normal HK-2 cells. Confocal displayed a strong cytoplasmic immno-fluorescence activity of GATA-3 with peri-nuclear zone in HK-2, whereas the intensity in cancer cells was markedly weaker than that of HK-2.

CONCLUSIONS

In summary, our present study clarifies that the aberrant expression profile of GATA-3 in human RCC is possibly involved with tumorigenesis, and the complicated mechanism is worthy of further investigation.

Organochlorine pesticides and polychlorinated biphenyls in soils surrounding the Tanggu Chemical Industrial District of Tianjin, China

The spatial distribution of persistent organic pollutants (POPs) was examined in soils surrounding the Tanggu Chemical Industrial District in Tianjin, China. The concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzenes (HCBs), and polychlorinated biphenyls (PCBs) were determined in 70 surface soils using accelerated solvent extraction and gas chromatography with electron capture detection. The results showed that the ranges of ∑HCH, ∑DDT, ΣHCB, and ∑PCB concentrations in soils were 2.1-12,549 μg kg(-1) (average, 965 μg kg(-1)), n.d.-2,033 μg kg(-1) (average, 88.4 μg kg(-1)), n.d.-1,924 μg kg(-1) (average, 349 μg kg(-1)), and n.d.-373 μg kg(-1) (average, 46.2 μg kg(-1)), respectively. Of these, HCHs were the dominant POPs, accounting for 75 % of the total organochlorine pesticide (OCP) residues. Overall, the spatial distribution of OCP concentrations showed a decreasing trend from the center of the Tanggu District to the surrounding areas. Two major pollution sources were Tianjin Dagu Chemical Co., Ltd. in the district center and the Tianjin Chemical Plant in Hangu District. In contrast, PCB concentrations were relatively high in the Haihe estuary to the east and low to the west of the study area. Component analysis of OCPs in these soils showed that they mainly came from industrial point sources. Compared with soils in other regions, soil DDT pollution was at a medium level in the Tanggu Chemical Industrial District, but associated HCH, HCB, and PCB pollution was relatively heavy. By multivariate statistical analyses, Tianjin Dagu Chemical Co., Ltd. was recognized as the main source of POPs, and soil properties were clarified to play an important role on the distribution and composition of POPs, especially the organic carbon content.

Naloxone inhibition of lipopolysaccharide-induced activation of retinal microglia is partly mediated via the p38 mitogen activated protein kinase signalling pathway

OBJECTIVES

To investigate the effects and underlying mechanism of action of naloxone on lipopolysaccharide (LPS)-induced activation of retinal microglia in vitro.

METHODS

Rat retinal microglia primary cultures were divided into four treatment groups: untreated; 1 μg/ml LPS for 12 h; 0.5, 1.0 or 2.0 μM naloxone for 30 min before LPS; 2.5 or 5.0 μM SB203580 for 12 h before LPS and naloxone. Levels of tumour necrosis factor (TNF)-α and interleukin (IL)-1β were determined by enzyme-linked immuno sorbent assay. Western blot analysis and double immunofluorescence were used to examine activation of the mitogen activated protein kinase (MAPK) signalling pathway.

RESULTS

LPS induced an increase in TNF-α and IL-1β in culture supernatants, which was dose-dependently inhibited by naloxone. Naloxone also dose-dependently inhibited LPS-induced increases in phosphorylated p38 MAPK. Pretreatment of cells with SB203580 attenuated the inhibitory effect of naloxone on TNF-α and IL-1β production.

CONCLUSIONS

Naloxone suppressed LPS-induced activation of cultured retinal microglia and this suppression appeared to occur partly through the p38 MAPK signalling pathway. Naloxone may have therapeutic potential in neuro degenerative diseases characterized by the activation of microglia.

Molecular cloning of a new wheat calreticulin gene TaCRT1 and expression analysis in plant defense responses and abiotic stress resistance

Calreticulin proteins play essential roles in regulating various metabolic processes and in molecular signal transduction in animals and plants. Using homologous PCR, we screened a cDNA library of the wheat resistance gene Yr5 from a near-isogenic line in the susceptible common wheat variety Taichung 29, which was inoculated with an incompatible race CYR32 of Puccinia striiformis. We isolated a novel full-length cDNA encoding calreticulin protein, which we named TaCRT1. Sequence analyses indicated that TaCRT1 contains an open reading frame of 1287 bp in length; it was deduced to encode 428 amino acids. Clustering analysis showed that TaCRT1 belongs to group III of the calreticulin protein family. Semi-quantitative RT-PCR was used to analyze expression profiles of the isolated gene under biotic and abiotic stresses. Expression of TaCRT1 was suppressed by exogenous application of phytohormones, such as abscisic acid and methyl jasmonate, and by dehydration; but it was induced by CYR32 infection and cold treatment. Based on the expression patterns, we propose that TaCRT1 participates in regulatory processes involved in defense responses and stress resistance in wheat.

Inhibition of the rapid component of the delayed rectifier potassium current in ventricular myocytes by angiotensin II via the AT1 receptor

BACKGROUND AND PURPOSE

There is increasing evidence that angiotensin II (Ang II) is associated with the occurrence of ventricular arrhythmias. However, little is known about the electrophysiological effects of Ang II on ventricular repolarization. The rapid component of the delayed rectifier K(+) current (I(Kr)) plays a critical role in cardiac repolarization. Hence, the aim of this study was to assess the effect of Ang II on I(Kr) in guinea-pig ventricular myocytes.

EXPERIMENTAL APPROACH

The whole-cell patch-clamp technique was used to record I(Kr) in native cardiocytes and in human embryonic kidney (HEK) 293 cells, co-transfected with human ether-a-go-go-related gene (hERG) encoding the alpha-subunit of I(Kr) and the human Ang II type 1 (AT(1)) receptor gene.

KEY RESULTS

Ang II decreased the amplitude of I(Kr) in a concentration-dependent manner with an IC(50) of 8.9 nM. Action potential durations at 50% (APD(50)) and 90% (APD(90)) repolarization were prolonged 20% and 16%, respectively by Ang II (100 nM). Ang II-induced inhibition of the I(Kr) was abolished by the AT(1) receptor blocker, losartan (1 muM). Ang II decreased hERG current in HEK293 cells and significantly delayed channel activation, deactivation and recovery from inactivation. Moreover, PKC inhibitors, stausporine and Bis-1, significantly attenuated Ang II-induced inhibition of I(Kr).

CONCLUSIONS AND IMPLICATIONS

Ang II produces an inhibitory effect on I(Kr)/hERG currents via AT(1) receptors linked to the PKC pathway in ventricular myocytes. This is a potential mechanism by which elevated levels of Ang II are involved in the occurrence of arrhythmias in cardiac hypertrophy and failure.

Properties of MSW fly ash-calcium sulfoaluminate cement matrix and stabilization/solidification on heavy metals

In this paper, investigations were undertaken to formulate the properties of fly ash-calcium sulfoaluminate (CSA) cement matrix by blending MSW fly ash with CSA cement. The compressive strength, pore structure, hydration phases, and leaching behavior of Zn and Pb doped MSW fly ash-CSA cement matrices were determined by XRD, MIP, DSC, FTIR, EDX, TCLP leaching test and other experiments. The results showed that the addition of MSW fly ash to form fly ash-CSA cement matrix reduced the compressive strengths of matrices and made the pore distribution of matrices coarser, compared to that of pure CSA cement matrix. However, fly ash-CSA cement matrix could effectively immobilize high concentration of heavy metal such as lead and zinc with much lesser leaching of TCLP. Besides ettringite AFt, Friedel phase was a new hydration phase formed in the matrix. The formation of these hydration phases was responsible for huge reservoir of heavy metal stabilization by chemical fixing. Therefore, it could be postulated that MSW fly ash-CSA cement matrix was a potential new constituent of S/S matrix for high concentration of heavy metals such as Zn and Pb ions.

FePt nanocluster films for high-density magnetic recording

High anisotropy L1(0) ordered FePt thin films are considered to have high potential for use as high areal density recording media, beyond 1 Tera bit/in2. In this paper, we review recent results on the synthesis and magnetic properties of L1(0) FePt nanocomposite films. Several fabrication methods have been developed to produce high-anisotropy FePt films: epitaxial and non-epitaxial growth of (001)-oriented FePt:X (X = Au, Ag, Cu, C, etc.) composite films that might be used for perpendicular media; monodispersed FePt nanocluster-assembled films grown with a gas-aggregation technique and having uniform cluster size and narrow size distribution; self-assembled FePt particles prepared with chemical synthesis by reduction/decomposition techniques, etc. The magnetic properties are controllable through variations in the nanocluster properties and nanostructure. FePt and related films show promise for development as heat-assisted magnetic recording media at extremely high areal densities. The self-assembled FePt arrays show potential for approaching the ultimate goal of single-grain-per-bit patterned media.

Research on inhibitive behaviors of electrolysis on the growth of Microcystis aeruginosa

Electrochemical method using a novel Ti/RuO2 anode was employed to inhibit a typical cyanobacteria, Microcystis aeruginosa (M. aeruginosa) under different electrolytic conditions. It is demonstrated that Ti/RuO2 anode was more efficient than traditional graphite anode in M. aeruginosa inhibition. The experimental results showed that the higher current density or longer electrolytic time could effectively improve the inhibition of M. aeruginosa. In addition, sodium chloride was a more effective electrolyte than sodium sulfate to enhance inhibition. The maximum inhibiting rate dose to 100% could be obtained at a current density of 12 mA cm(-2) when sodium chloride was used as a supporting electrolyte. Furthermore, UV-Visible spectra demonstrated that the structures of phycocyanins and chlorophyll a (Chl a) in M. aeruginosa could be changed or destroyed during electrolysis. Moreover, EPR spectra showed the generation of the free radicals through electrolysis, which might be one of the reasons responsible for the inhibition of algal growth.

The tumor suppressor adenomatous polyposis coli gene is associated with susceptibility to schizophrenia

The etiology of schizophrenia is unclear, although family, twin, and linkage studies implicate genetic factors. Here, we identified adenomatous polyposis coli (APC), a tumor suppressor gene, as a risk factor for schizophrenia. We compared leukocytic gene expression patterns of six pairs of patients with schizophrenia and healthy controls by microarray. APC expression levels were significantly increased in all patients compared to healthy controls. To confirm the findings of microarray analysis, we measured expression levels of APC in the leukocytes from 30 relapse patients taking antipsychotic medication, 29 first-episode drug-naïve patients, and 30 healthy controls using real-time quantitative reverse transcription (RT)-polymerase chain reaction (PCR). APC expression levels were significantly increased in leukocytes of schizophrenics both taking and not taking antipsychotic medication and hence the increase of APC expression was not due to antipsychotic medication. APC is located at 5q21-22, which has been previously reported to be linked with schizophrenia. Further, we performed the transmission disequilibrium test (TDT) and TDT based on haplotypes to search for the association between schizophrenia and APC by examining 163 parent-offspring trios of Chinese descent. We analyzed three single-nucleotide polymorphisms (SNPs) (rs2229992, rs42427, rs465899) at the exon region of APC. TDT showed that the three SNPs are significantly associated with schizophrenia (TDT chi(2)=4.23, P<0.05; 4.15, P<0.05; 8.49 P<0.01, respectively; HHRRchi(2)=5.54, P<0.05; 4.40, P<0.05; 9.79, P<0.01, respectively). We found a significant association between the APC haplotypes from rs2229992-rs42427-rs465899 and schizophrenia (Global chi(2)=44.376,df=7, P<0.001). The C-A-T haplotype has a frequency of more than 57% and has a strong association with schizophrenia (chi(2)=15.04, P<0.001). These results indicate that the APC may be a candidate gene conferring susceptibility to schizophrenia and also may be associated with reduced vulnerability to cancer in schizophrenia.

Possible association of the MAG locus with schizophrenia in a Chinese Han cohort of family trios

Neurotransmitter-based hypotheses have so far led to only moderate success in predicting new pathogenetic findings in etiology of schizophrenia. On the other hand, the more recent oligodendroglia hypotheses of this disorder have been supported by an increasing body of evidence. For example, the expression level of the myelin associated glycoprotein (MAG) gene has been shown to be significantly lower in schizophrenia patient groups compared to control groups. Such an effect might be a result of genetic variations of the MAG gene. In order to test this hypothesis, we genotyped four markers within the MAG locus in 413 trios sample of the Han Chinese using allele-specific PCR. None of the four markers revealed noticeable allelic significance. However, the four-marker and two-marker haplotypes covering components rs720309 and rs720308 were observed to be significantly associated with schizophrenia (P < 0.0001) in this study. In addition, we identified one common risk haplotype TA (rs720309-rs720308, present in 78.5% of the general population) that showed increased evidence of overtransmission from parents to affected offspring (P = 0.0001). The results demonstrated MAG might play a role in genetic susceptibility to schizophrenia. Furthermore, our finding of a possible association between the MAG locus and schizophrenia is in agreement with the hypotheses of oligodendrltic and myelination dysfunction.

Quantitative analysis of the response of an electrochemical biosensor for progesterone in milk

An electrochemical biosensor for progesterone in cow's milk was developed and used in a competitive immunoassay by Hart et al. (1977, Studies towards a disposable screenprinted amperometric biosensor for progesterone, Biosens. Bioelectron. 12, 1113-1121). The sensor was fabricated by depositing anti-progesterone monoclonal antibody (mAb) onto screen-printed carbon electrodes (SPCEs) which were coated with rabbit anti-sheep IgG (rIgG). This sensor was operated following the steps of competitive binding between sample and conjugate (alkaline-phosphatase-labelled progesterone) for the immobilised mAb sites and measurements of an amperometric signal in the presence of p-nitrophenylphosphate using either colorimetric assays or cyclic voltammetry. The hook effect of the progesterone biosensor was found in the concentration range of milk progesterone between 0 and 5 ng/ml when the sensor was fabricated using a loading of 25 ng rIgG per electrode of a diameter of 3 mm and a 1/50 dilution of mAb. A computer model has been developed in this study to simulate the operation of this progesterone biosensor with consideration of the fabrication processes. This paper presents the results of validating the computer model and the model has predicted the hook effect as observed in tests. The model thus reveals that the hook effect is determined by the total number of binding sites available and the rates of labelled and unlabelled progesterone diffusing towards the sensor surface and the binding rates.

[Role of calcineurin in cardiac fibroblast proliferation stimulated by angiotensin II]

The present study was undertaken to observe the role of calcineurin (CaN) in the angiotensin II (Ang II) stimulated cardiac fibroblast proliferation. In cultured cardiac fibroblasts of neonatal rats, Ang II was used to stimulate proliferation while CaN was inhibited by CaN CsA inhibitor cyclosporin A (CsA). (3)H-TdR incorporation, activity of CaN and intracellular calcium concentration were measured. (3)H-TdR incorporation of Ang II stimulated fibroblasts was 72% higher than control (P<0.01), which was inhibited by CsA (0.1 10 micromol/L) in a dose dependent manner. Intracellular Ca(2+) level and CaN activity of Ang II stimulated fibroblasts were respectively 112% (P<0.01) and 17%(P<0.05) higher than control. It is concluded that CaN may play an important role in signal transduction of the Ang II induced cardiac fibroblast proliferation.

Effect of moxonidine on carotid sinus baroreflex in anesthetized rats

AIM

To study the effect of moxonidine (Mox) on carotid sinus baroreflex.

METHODS

By perfusing the carotid sinus in anesthetized rats, the functional parameters of baroreflex were measured. The femoral artery was perfused with constant flow and the change of perfusing pressure was recorded to determine the effect of Mox on vascular tone.

RESULTS

Mox 32 and 100 mumol.L-1 shifted the functional curve of carotid sinus baroreflex to the right and upward, with the reduction in peak slope and in reflex decrease of mean arterial pressure, suggesting that Mox produced an inhibitory effect on baroreflex. The effect of Mox 100 mumol.L-1 on baroreflex was completely blocked by efaroxan 100 mumol.L-1. Mox increased vascular resistance.

CONCLUSION

Mox inhibits carotid baroreflex via its constrictive action on sinus wall.

[Isolation of novel expression sequences of C2H2 type zinc finger protein gene from human brain tissue according to the conservation of zinc finger motif]

By low stringency PCR amplification of genomic DNA using the primers designed based on the conservation of zinc finger motif, we got 8 gradient eletrophoretic bands. After recovery of the second and third bands, the DNA fragments in them were cloned and sequenced. Compared to the GenBank database, among these 60 segments containing zinc finger motif, 23 segments were novel zinc finger genes' genomic segments. Then the human brain tissue cDNA library was screened, using these segments as probes, and 44 positive clones were obtained. Rescreening 28 of them, we got 20 rescreened clones. All of them were sequenced and sent to the GenBank DNA database for sequence analysis, the results showed that 16 were novel C2H2 type zinc finger protein cDNA segments. The cDNA segments encoding the novel C2H2 type zinc finger proteins provide the basic materials for cloning of full length cDNA of valuable novel zinc finger protein genes.

Passive transfer of Lambert-Eaton myasthenic syndrome induces dihydropyridine sensitivity of ICa in mouse motor nerve terminals

Mice were injected for 30 days with plasma from three patients with Lambert-Eaton Myasthenic Syndrome (LEMS). Recordings were made from the perineurial sheath of motor axon terminals of triangularis sterni muscle preparations. The objective was to characterize pharmacologically the identity of kinetically distinct, defined potential changes associated with motor nerve terminal Ca2+ currents (ICa) that were affected by LEMS autoantibodies. ICa elicited at 0.01 Hz were significantly reduced in amplitude by approximately 35% of control in LEMS-treated nerve terminals. During 10-Hz stimulation, ICa amplitude was unchanged in LEMS-treated motor nerve terminals, but was depressed in control. During 20- or 100-Hz trains, facilitation of ICa occurred in LEMS-treated nerve terminals whereas in control, no facilitation occurred during the trains at 20 Hz and marked depression occurred at 100 Hz. Saturation for amplitude and duration of ICa in control terminals occurred at 2 and 4-6 mM extracellular Ca2+, respectively; in LEMS-treated terminals, the extracellular Ca2+ concentration had to increase by two to three times of control to cause saturation. Amplitude of the two components of ICa observed when the preparation was exposed to 50 microM 3,4-diaminopyridine and 1 mM tetraethylammonium were both reduced by LEMS plasma treatment. The fast component (ICa,s) was reduced by 35%, whereas the slow component (ICa, s) was reduced by 37%. omega-Agatoxin IVA (omega-Aga-IVA; 0.15 microM) and omega-conotoxin-MVIIC (omega-CTx-MVIIC; 5 microM) completely blocked ICa in control motor nerve terminals. The same concentrations of toxins were 20-30% less effective in blocking ICa in LEMS-treated terminals. The residual ICa remaining after treatment with omega-Aga-IVA or omega-CTx-MVIIC was blocked by 10 microM nifedipine and 10 microM Cd2+. Thus LEMS plasma appears to downregulate omega-Aga-IVA-sensitive (P-type) and/or omega-CTx-MVIIC-sensitive (Q-type) Ca2+ channels in murine motor nerve terminals, whereas dihydropyridine (DHP)-sensitive (L-type) Ca2+ channels are unmasked in these terminals. Acute exposure (90 min) of rat forebrain synaptosomes to LEMS immunoglobulins (Igs; 4 mg/ml) did not alter the binding of [3H]-nitrendipine or [125I]-omega-conotoxin-GVIA (-omega-CgTx GVIA) when compared with synaptosomes incubated with an equivalent concentration of control Igs. Conversely, LEMS Igs significantly decreased the Bmax for [3H]-verapamil to approximately 45% of control. The apparent affinity of verapamil (KD) for the remaining receptors was not significantly altered. Thus acute exposure of isolated central nerve terminals to LEMS Igs does not increase DHP sensitivity, whereas it reduces the number of binding sites for verapamil but not for nitrendipine or omega-CgTx-GVIA. These results suggest that chronic but not acute exposure to LEMS Igs either upregulates or unmasks DHP-sensitive Ca2+ channels in motor nerve endings.

Effects of moxonidine injected into rostral ventrolateral medulla on blood pressure, heart rate, and renal sympathetic nerve activity in rats

AIM

To examine the effects of moxonidine (Mox) injected into the rostral ventrolateral medulla (RVLM) on blood pressure (BP), heart rate (HR), and the renal sympathetic nerve activity (RSNA) in anesthetized normotensive rats.

METHODS

BP, HR, and RSNA were simultaneously recorded after 1 microL Mox 1, 10, and 100 mumol.L-1 was injected into RVLM.

RESULTS

Mox 1, 10, and 100 mumol.L-1 reduced BP from 13.9 +/- 1.0 kPa to 13.0 +/- 1.7 kPa (P < 0.05), 13.8 +/- 1.8 kPa to 11.4 +/- 1.5 kPa (P < 0.01), and 13.9 +/- 1.9 kPa to 9.4 +/- 1.7 kPa (P < 0.01), respectively. Mox did not influence HR. RSNA varied with the doses: Mox 1 mumol.L-1 increased RSNA by 50% (P < 0.05), 10 mumol.L-1 insignificantly influenced RSNA (P > 0.05), and 100 mumol.L-1 reduced RSNA by 23% (P < 0.05). In sinoaortic barodenervated rats, Mox 10 mumol.L-1 inhibited RSNA by 50% (P < 0.05), which substantially differed from that in buffer nerve intact rats (P < 0.01).

CONCLUSION

Mox injected into RVLM decreased BP, but did not influence HR. The changes of RSNA did not parallel with the depressor effect of Mox.