The transient appearance of collateral circulation during coronary spasm

This article reports a case of transient augmentation of collateral circulation due to spontaneous coronary arterial spasm during angiography. The patient's electrocardiogram revealed ST-segment depression during vasospastic attack; this depression differs from the typical change of the ST-segment elevation in coronary spasm without collateral circulation.

[Gene cloning, construction and expression of single-chain Fv (scFv) against the membrane protein of Schistosoma japonicum]

OBJECTIVE

To construct single chain antibody specific to membrane protein of Schistosoma japonicum by genetic engineering technique.

METHODS

The VH (heavy-chain variable region) and VL(light-chain variable region) genes were amplified by PCR from the genomic DNA of NP11-4 cell line, and sequenced by Sanger's method. The ScFv was constructed in pTHA90 vector using VH and VL genes, then expressed by IPTG.

RESULTS

The VH and VL genes were obtained through PCR. The DNA sequences showed that VH and VL were new variable region genes of antibody. They were registered by GenBank. A ScFv gene with (Gly4Ser) 3 intralinker in the pTHA90 vector was successfully constructed. The ScFv was expressed as thioredoxin-fused proteins about 36.2 kDa.

CONCLUSION

A specific ScFv against the membrane protein of Schistosoma japonicum was constructed and expressed.

[Cloning and sequence analysis of the light chain variable region gene of monoclonal anti-idiotypic antibody NP30 of Schistosoma japonicum]

OBJECTIVE

To amplify and sequence the light chain of anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum.

METHODS

By comparing the conserved regions at each end of the nucleotide sequences of murine germ-line genes encoding FR1 and FR4 regions of immunoglobulin light chain variable regions, we designed a set of primers for amplification of VL gene. The hybridoma cells secreting anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum were cultured and their genome DNAs were extracted and used as templates for PCR. The PCR product was then cloned into pUC19 vector. The recombinants were sequenced by Sanger's method. The VL gene was compared with GenBank and published mouse VL genes.

RESULTS

The full-length of VL gene was 318 bp. The VL gene was a member of mouse Ig kappa light chain subgroup IV and generated from rearrangement of germ line V and J kappa 4 genes. The VL gene sequence has been registered by GenBank(accession No. AF206720).

CONCLUSION

The obtained VL gene was a potentially functional gene of anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum.

Thermal contraction of au nanoparticles

A fine Au powder, with a mean particle diameter of 4 nm, has been successfully fabricated. The crystalline structure of the 4 nm Au nanoparticles remains in fcc symmetry. No structural changes were found between 15 and 450 K. A crossover from a positive thermal expansion at low temperatures to a negative thermal expansion at high temperatures was observed in the fcc cell parameter at about 125 K. Anomalies associated with the crossover were also observed in the magnetic response and the heat capacity measurements. The observations can be reasonably well interpreted by accounting for the effects of the valence electron potential on the equilibrium lattice separations, with a weakly temperature dependent level spacing.

Hepatitis B viral polymerase fusion proteins are biologically active and can interact with the hepatitis C virus core protein in vivo

Hepadnaviruses and retroviruses are evolutionarily related families because they both require a process of reverse transcription for genome replication. However, hepadnaviruses produce polymerase (pol) and core proteins separately, while retroviruses synthesize a gag-pol fusion protein that is subsequently cleaved by a virally encoded protease to release a functional polymerase. To test whether an additional sequence at the N-terminus of pol in hepatitis B virus (HBV) interferes with its function, we created two plasmids expressing core-pol fusion proteins, core144-pol and core31-pol. Secreted particles obtained from HuH-7 cells, which were cotransfected with a core-pol fusion protein-expressing plasmid and a core-expressing plasmid, showed a positive signal of HBV DNA by the endogenous polymerase assay, indicating that the core-pol fusion proteins retain DNA priming, polymerization and RNase H activities. The fusion protein was detected in the cytoplasm of transfected cells and in secreted virions by immunoprecipitation. Furthermore, we found by immunofluorescence staining that the HBV core-pol fusion protein colocalized with the hepatitis C virus (HCV) core protein in cytoplasm and in lipid droplets. Immunoprecipitation studies showed that the anti-HCV core complex contained the HBV core-pol fusion protein while the anti-HBV pol complex contained the HCV core protein, which supports the hypothesis that the HCV core protein can form a complex with the HBV core-pol fusion protein.

[Advances in in vitro refolding of inclusion body proteins]

Overexpression of recombinant proteins in E. coli often results in formation of insoluble, inactive inclusion bodies. These inclusion bodies, which contain the recombinant proteins in a highly enriched form, can be isolated by solid/liquid separation. After solubilization, active proteins can be generated through an appropriate refolding process. Within the last decade, specific strategies and methods have been developed for preparing active recombinant proteins from inclusion bodies. Recent developments in renaturation procedure include the inhibition of aggregation during refolding by the application of low molecular weight additives and matrix-bound renaturation techniques.

Modulation of QT interval by cardiac sympathetic nerve sprouting and the mechanisms of ventricular arrhythmia in a canine model of sudden cardiac death

INTRODUCTION

We previously reported that there is a high incidence of sudden cardiac death (SCD) in dogs with myocardial infarction (MI), complete AV block (CAVB), and nerve growth factor (NGF) infusion to the left stellate ganglion (LSG). Whether or not QT interval prolongation underlines the mechanism of SCD was unclear.

METHODS AND RESULTS

We analyzed QT intervals in three groups of dogs. All dogs had CAVB and MI. The LSG group (n = 9) and right stellate ganglion (RSG) group (n = 6) received NGF infusion via the osmotic pumps over a 5-week period to LSG and RSG, respectively. The control group (n = 6) received no NGF. The dogs either died suddenly or were sacrificed within 2 to 3 months after MI. Heart rhythm and QT and RR intervals were monitored using implantable cardioverter defibrillator ECG recordings. There was a time-dependent increase of QTc intervals in the LSG group and a time-dependent decrease of QTc intervals in the RSG group. At the end of NGF infusion, QTc intervals in the LSG group (408 +/- 41 msec) were significantly longer than those in the control (350 +/- 41 msec; P < 0.05) and RSG groups (294 +/- 23 msec; P < 0.01). In the LSG group, 4 of 9 dogs died of SCD. There was no SCD in either the RSG or control group. Immunocytochemical staining showed NGF infusion to LSG and RSG resulted in left and right ventricular sympathetic nerve sprouting and hyperinnervation, respectively.

CONCLUSION

NGF infusion to the LSG in dogs with MI and CAVB resulted in increased QT interval and incidence of ventricular tachycardia, ventricular fibrillation, and SCD, whereas NGF infusion to the RSG shortened QT interval and reduced the incidence of ventricular tachycardia. These findings indicate that QT interval prolongation is causally related to the occurrence of ventricular arrhythmia in dogs with nerve sprouting, MI, and CAVB.

Enhanced naphthalene solubility in the presence of sodium dodecyl sulfate: effect of critical micelle concentration

Surfactants can increase the solubility of non-polar compounds, and have been applied in areas such as soil washing and treatment of non-aqueous phase liquids (NAPLs). This investigation explored the feasibility of removing vapor phase polycyclic aromatic hydrocarbon (PAH) from gases using an anionic surfactant. The solubility of vapor phase naphthalene was measured herein using gas chromatograph (GC) with a photon ionization detector (PID). The measurement results indicated that surfactant molecules were not favorable to micelle formation when temperatures increased from 25 degrees C to 50 degrees C. Regardless of whether solutions were quiescent or agitated, equilibrium naphthalene apparent solubility increased linearly with surfactant concentrations exceeding critical micelle concentration (CMC). The pH effects on naphthalene apparent solubility were small. Agitation increased naphthalene apparent solubility and lumped mass transfer coefficients. Furthermore, lumped mass transfer coefficients decreased with increasing surfactant concentration owing to increase in interfacial resistance and viscosity and decreased spherical micelle diffusion coefficients. Finally, the net absorption rate increased because the solubilization effects of micelles exceeded the reduction effects of mass transfer coefficient above the CMC. The enhanced naphthalene apparent solubility from the addition of surfactant can be expressed by an enrichment factor (EF). The EF value of naphthalene for the surfactant solution at 0.1 M with agitation at 270 rpm relative to quiescent water could reach 18.6. This work confirms that anionic surfactant can improve the removal efficiency of hydrophobic organic compound (HOC) from the gas phase.

[Determination of active ingredients of 12 pesticides by capillary gas chromatography]

A method for the determination of the active ingredients of 12 pesticides, including procymidone and tebuconazole, with capillary gas chromatography has been developed. A wide bore capillary column(SE-30) and FID detector were employed. The internal standards were used for quantitative determination and GC/MS for qualitative determination. The average recoveries were 99.20%-102.44% while the relative standard deviations were within the range of 0.07% to 5.49%. The method is simple, practical and accurate for the determination of the active ingredients of individual pesticide, formulation or multi-pesticides as a whole.

Effects of zinc deficiency on the vallate papillae and taste buds in rats

BACKGROUND AND PURPOSE

Zinc deficiency is associated with multiple clinical complications, including taste disturbance, anorexia, growth retardation, skin changes, and hypogonadism. We investigated the zinc-deficiency-induced morphologic changes in the vallate taste buds of weanling and young adult male Wistar rats.

METHODS

A total of 24 weanling and 30 young adult rats were used. Each age group was further divided into a control group fed a zinc-adequate (50 ppm) diet, a zinc-deficient (< 1 ppm) diet group, and a zinc-adequate pair-fed group who were fed the same amount of food as that taken by the zinc-deficient group. Weanling rats were fed for 4 weeks and young adult rats were fed for 6 weeks. The morphometry and morphologic changes of vallate taste buds were analyzed using light and transmission electron microscopy.

RESULTS

Light microscopy revealed no significant difference in papilla size and morphology among the various groups. In both weanling and young adult rats in the zinc-deficient diet and pair-fed groups, the number of taste buds per papilla (per animal) and the average profile area of the taste bud were significantly smaller than those of the corresponding controls (p < 0.05). Ultrastructural changes were seen only in the taste buds of weanling rats fed the zinc-deficient diet, with derangement of the architecture of the taste bud and widening of the intercellular space between taste bud cells. The proportion of type I taste bud cells in the taste buds of weanling rats fed the zinc-deficient diet decreased from 59% to 39%, and that of type II taste bud cells decreased from 25% to 12%. No obvious changes in the ultrastructure of type III taste bud cells were observed.

CONCLUSIONS

The main effects of zinc deficiency in weanling and young adult rats and in adequate diet pair-fed rats were changes in the number and size of taste buds, and fine structure changes in the taste bud cells, especially during the accelerated growth stage after weaning.

Conformational changes play a role in regulating the activity of the proline utilization pathway-specific regulator in Saccharomyces cerevisiae

In Saccharomyces cerevisiae, the ability to use proline as a nitrogen source requires the Put3p transcriptional regulator, which turns on the expression of the proline utilization genes, PUT1 and PUT2, in the presence of the inducer proline and in the absence of preferred nitrogen sources. Changes in target gene expression occur through an alteration in activity of the DNA-bound Put3p, a member of the Zn(II)2Cys6 binuclear cluster family of proteins. Here, we report that the 'on' conformation can be mimicked in the absence of proline by the insertion of an epitope tag in several different places in the protein, as well as by specific amino acid changes that suppress a put3 mutation leading to non-inducibility of the pathway. In addition, the presence of proline causes a conformational change in the Put3 protein detected by increased sensitivity to thrombin or V8 protease. These findings suggest that Put3p shifts from an inactive to an activate state via conformational changes.

[Analysis of HLA-DQB1 polymorphism by PCR-SSO in Yichu of Yunnan Province]

HLA-DQB1 genes from 76 individuals of Yichu ethnic group in Yunnan Province were investigated, using PCR-SSO genotyping method. Of the 38 DQB1 alleles detected, DQB1 * 0301 (gene frequency: 36.18%-36.84%) was the most common gene. The frequencies of DQB1 * 0502(10.53%-11.18%), DQB1 * 0401 (9.21%), DQB1 * 0302(8.55%-9.21%), DQB1 * 0601(7.89%), DQB1 * 05031(6.58%), and DQB1 * 03032(5.92%-6.58%) are more than 5%. While DQB1 * 0504, DQB1 * 0604, DQB1 * 06052, DQB1 * 0606, DQB1 * 0607, DQB1 * 0608, DQB1 * 06112, DQB1 * 0613, DQB1 * 0615, DQB1 * 0203, DQB1 * 0305, DQB1 * 0306, DQB1 * 0307, and DQB1 * 0308 were not observed. Comparison of HLA-DQB1 allele frequencies of Yichu with those of 13 other Chinese ethnic groups showed some significant differences, suggesting Yichu is unique in the distribution of HLA alleles.

[Expression of single-chain Fv antibody for anti-beet necrotic yellow vein virus in Escherichia coli]

The heavy chains variable region gene (VH) of monoclonal antibody against beet necrotic yellow vein virus (BNYVV) was amplified from total DNA extracted from anti-BNYVV hybridoma cells by PCR. Sequencing showed that the VH belongs to mouse subgroup II(A) and contains 360 bp, which code one hundred and twenty amino acids. The VH and VL genes were inserted into a plasmid which contains a linker sequence for constructing scFv gene. The new vector named pTC scFv. The scFv was produced in Escherichia coli and appeared binding activity with BNYVV antigen by ELISA method.

[Construction, expression and activity test of a reshaping single-chain antibody against human CD3]

Monoclonal antibody (McAb) against human CD3 can adjust human body's immune statement in various ways, so that its clinical potential is highly regarded. In order to overcome the immunogenecity related to the murine McAb, this research effort was focused on constructing a reshaping single-chain antibody(scFv) against human CD3 employing antibody engineering. First, the CDRs of the murine McAb against human CD3 OKT3 was transplanted into the light-chain framework regions (FRs) of human McAb LS1 and the heavy-chain FRs of human McAb Nd respectively, spatial conformation was predicted by computer analysis. Then some particular residues were replaced in FRs basing on the result of conformational prediction to draw out the amino acid sequences of the reshaped VL and VH. The genes were chemically synthesize and inserted into an expression vector pROH80 to construct the reshaping scFv. Inducing the expression of reshaping scFv, the products are mainly as inclusion bodies. The reshaping scFv was expressed in another vector pALM. The inclusion bodies were denatured and then renatured by gel filtration. The renatured products were purified by immobilized metal affinity chromatograph (IMAC). Finally, the antigen-binding activily of the reshaping scFv against human CD3 was testified by the Compelitire in hibilory fluorescenceactivated cell sorting (FACS). The competitive inhibition rate is 18%.

Pulmonary veins and ligament of Marshall as sources of rapid activations in a canine model of sustained atrial fibrillation

BACKGROUND

In dogs, chronic rapid pacing may result in sustained atrial fibrillation (AF). However, activation patterns in pacing-induced sustained AF are unclear.

METHODS AND RESULTS

We induced sustained AF (>48 hours) in 6 dogs by rapid pacing for 139+/-84 days. We then performed computerized atrial epicardial mappings and recorded the activations in the ligament of Marshall (LOM) and the pulmonary veins (PVs). During AF, mean activation cycle length in the right atrial free wall (126+/-17 ms) was significantly longer than that in the left atrial free wall (96+/-5 ms, P:=0.006). In addition, mean activation cycle length in the left atrial free wall was significantly longer than that in the LOM (84+/-5 ms, P:<0.001), the left inferior PV (81+/-4 ms, P:=0.001), and the left superior PV (85+/-7 ms, P:=0.003). Similarly, the dominant frequency was highest in the LOM and the PVs (range 11.2 to 13.3 Hz), followed by the left and right atria (P:<0.001). In all dogs studied, rapid and complicated electrograms were consistently observed at the LOM and the PVs. During AF, both wandering wavelets and organized reentry were present. There were more wave fronts in the left atrium than in the right atrium (P:<0.001).

CONCLUSIONS

In chronic pacing-induced sustained AF, the LOM and the PVs are the sources of rapid activations. The mechanism by which the left atrium activates faster and has more wave fronts than the right atrium may relate to the fact that the left atrium is closer to the sources of rapid activations.

Simultaneous absorption of vapor phase polycyclic aromatic hydrocarbon and carbon dioxide in anionic surfactant solutions

The goal of this work was to investigate whether the solubility of vapor phase polycyclic aromatic compounds (PAHs) and CO2 in water could be enhanced by adding anionic surfactant during the absorption process. Naphthalene was the PAH surrogate and sodium dodecyl sulfate (SDS) was the anionic surfactant. A series of batch experiments in an absorption cell were performed at 50 degrees C with the surfactant concentration both lower than and higher than the critical micelle concentration (CMC). The experimental findings indicate that the CMC was not a function of pH at values of 3, 5 and 7. Furthermore, at surfactant concentrations less than the CMC, naphthalene apparent solubility increased slightly. On the other hand, the equilibrium naphthalene or CO2 apparent solubility increased linearly, in proportion to the surfactant concentration at concentrations greater than the CMC. This is due to the solubilization effect of micelles, which were formed by the surfactant at concentrations above the CMC. During simultaneous absorption of the two, the presence of CO2 only slightly decreased naphthalene apparent solubility, while the apparent solubility of CO2 was drastically reduced in the presence of naphthalene. As the magnitude of the micelle solubilization effect was greater than the reduction of the mass transfer coefficient in the presence of the surfactant, the total gas absorption rate increased. When the surfactant concentration was 0.1 M, the enrichment factor (the ratio of the solubility in surfactant solution to that in water) values of naphthalene both with and without CO2 increased to 9.05 and 8.60, respectively. These experimental findings demonstrate that anionic surfactant may be applied to increase the removal efficiency of hydrophobic compounds and CO2 through either a spray or packed tower.

Anti-hepatitis B virus effects of wogonin isolated from Scutellaria baicalensis

By using an HBV-producing cell line (MS-G2) in vitro culture system, we found that wogonin isolated from Scutellaria baicalensis can suppress HBV surface antigen production (P < 0.001) without evidence of cytotoxicity. By assaying the endogenous HBV DNA polymerase activity, we found that both the relaxed circular and the linear forms of HBV DNA are significantly reduced in the wogonin-treated group. Wogonin deserves to be further evaluated for the treatment of human HBV infection.

Identification and characterization of a structural protein of hepatitis B virus: a polymerase and surface fusion protein encoded by a spliced RNA

The hepatitis B virus (HBV) genome is known to contain four conserved and overlapped open reading frames (ORFs) encoding the viral core, polymerase (P), surface (S), and X proteins. Whether HBV encodes other proteins has long been a major interest in the field. Using (32)P-labeling of an introduced protein kinase A site attached to the N- or C-terminus of the HBV polymerase gene, a 43-kDa P-S fusion protein was detected in cell lysate, secreted virions, and 22-nm subviral particles. Immunobiochemical studies showed that the 43-kDa protein contains the epitopes of the N-terminus of polymerase and most parts of the surface proteins. This 43-kDa protein was shown to be a glycoprotein, similar to the surface protein. RT-PCR and sequence analyses identified a spliced mRNA which was derived from pregenomic RNA with a deletion of 454 nucleotides (nt) from nt 2447 to 2902. This splice event creates a P-S fusion ORF. This finding is consistent with the result obtained from an immunobiochemical study. Mutations at the splice donor or acceptor site on the HBV genome abrogated the production of the 43-kDa protein. These mutants had no effect on viral replication in transfected HuH-7 cells. However, this P-S fusion protein is able to substitute for the LS protein in virion maturation. On the basis of these results, we conclude that the 43-kDa protein is a polymerase-surface fusion protein encoded by a spliced RNA. Similar to the LS protein, the 43-kDa P-S fusion protein is a structural protein of HBV and might play a role in the HBV life cycle.

Mechanisms of ventricular fibrillation induction by 60-Hz alternating current in isolated swine right ventricle

BACKGROUND

The mechanisms by which 60-Hz alternating current (AC) can induce ventricular fibrillation (VF) are unknown.

METHODS AND RESULTS

We studied 7 isolated perfused swine right ventricles in vitro. The action potential duration restitution curve was determined. Optical mapping techniques were used to determine the patterns of activation on the epicardium during 5-second 60-Hz AC stimulation (10 to 999 microA). AC captured the right ventricles at 100+/-65 microA, which is significantly lower than the direct current pacing threshold (0.77+/-0.45 mA, P:<0.05). AC induced ventricular tachycardia or VF at 477+/-266 microA, when the stimulated responses to AC had (1) short activation CLs (128+/-14 ms), (2) short diastolic intervals (16+/-9 ms), and (3) short diastolic intervals associated with a steep action potential duration restitution curve. Optical mapping studies showed that during rapid ventricular stimulation by AC, a wave front might encounter the refractory tail of an earlier wave front, resulting in the formation of a wave break and VF. Computer simulations reproduced these results.

CONCLUSIONS

AC at strengths less than the regular pacing threshold can capture the ventricle at fast rates. Accidental AC leak to the ventricles could precipitate VF and sudden death if AC results in a fast ventricular rate coupled with a steep restitution curve and a nonuniform recovery of excitability of the myocardium.

Influence of wavefront dynamics on transmembrane potential characteristics during atrial fibrillation

INTRODUCTION

Although computerized mapping studies have demonstrated the presence of multiple wavelets during atrial fibrillation (AF) and that action potential amplitude and duration in AF vary significantly from beat to beat, no study has correlated the single cell action potential changes with the patterns of activation during AF.

METHODS AND RESULTS

We studied wavefront dynamics and single cell transmembrane potential (TMP) characteristics in 12 isolated perfused canine right atria. The endocardial surface was mapped using 477 bipolar electrodes while TMP was recorded with a standard glass microelectrode from an epicardial cell. AF was induced in the presence of acetylcholine. Successful simultaneous TMP recordings and activation maps were made during six episodes of AF and for a total of 141 activations. Large variations of TMP amplitude and duration were observed frequently; 34% of them have a low amplitude (<50% of the amplitude recorded during pacing). Low-amplitude potentials were recorded when the impaled cell was (1) in an area of random reentry (67%, n = 36); (2) within 3.2 mm of the core of organized functional reentry (22%, n = 12); (3) in the middle of two merging wavefronts (9%, n = 5); and (4) at the point of spontaneous wavebreak (2%, n = 1).

CONCLUSION

Large variations of TMP are observed frequently during in vitro AF. Low-amplitude TMPs are associated with specific patterns of AF activation wavefronts.

Probucol inhibits lipid peroxidation of macrophage and affects its secretory properties

AIM

To investigate the mechanisms of anti-atherogenic actions of probucol.

METHODS

Human peripheral blood monocytes were cultured, and treated by copper ion (10 mumol/L) and/or probucol (PBC). Lipid peroxidation was measured by assaying malondialdehyde (MDA). The cytokine interleukin-1 beta (IL-1 beta) and apolipoprotein E (apo E) secreted by monocyte were assayed by enzyme linked immunoassay (ELISA).

RESULTS

PBC 10-80 mumol/L inhibited copper ion-induced cellular lipid peroxidation from 15.30 to 7.74 mumol MDA/g cell protein. PBC 40 mumol/L inhibited oxidized macrophage-mediated oxidation of LDL from 5.18 to 1.65 mumol MDA/g cell protein, and attenuated secretory properties of monocytes induced by copper ion. The release of apo E, which is involved in reverse cholesterol transport, increased by 65%. And the release of IL-1 beta, which was shown to enhance vascular smooth muscle cell proliferation, decreased by 45%.

CONCLUSION

Probucol inhibits lipid peroxidation of macrophages and affects their secretory properties.