Impaired forearm reactive hyperemia is related to late restenosis after coronary stenting

To investigate whether systemic endothelial function on forearm resistance vessels is related to angiographic restenosis after coronary stenting, 47 men who underwent elective coronary stenting were divided into 2 groups according to the presence (n = 20) or absence (n = 27) of in-stent restenosis 6 months after the procedure. Another 19 risk factor-matched men with normal coronary angiograms served as the control group. Forearm blood flow was assessed by venous occlusive plethysmography. Basal forearm blood flow was similar between restenosis, nonrestenosis, and control groups (2.63 +/- 0.19, 2.58 +/- 0.14, and 3.23 +/- 0.13 ml/100 ml forearm tissue per minute, respectively). In all 3 groups, forearm blood flow increased significantly during reactive hyperemia (5.75 +/- 0.7, 11. 32 +/- 1.23, and 14.52 +/- 1.36 ml/100 ml forearm tissue per minute, p <0.05, respectively) and remained unchanged after sublingual administration of nitroglycerin. The percentage change of forearm blood flow during reactive hyperemia was significantly lower in the restenosis group (117.3 +/- 18.3%) than in the nonrestenosis group (354.2 +/- 46.5%, p <0.01). This difference was still present after sublingual nitroglycerin (37.6 +/- 21.2% vs 226.4 +/- 40.5%, p <0. 01). In contrast, percentage change of hyperemic forearm blood flow was significantly lower in patients with angina (117.5 +/- 49.5%) than in those without angina (290.1 +/- 37.4%, p <0.05) at follow-up. In all patients, the angiographic loss index was correlated negatively to the percentage change of hyperemic forearm blood flow (r = -0.33, p <0.01) and positively to the percentage change of forearm vascular resistance during reactive hyperemia (r = 0.33, p <0.01). In patients with angiographic restenosis after coronary stenting, forearm reactive hyperemia was more impaired compared with those without angiographic restenosis. Systemic endothelial dysfunction might be either a marker or one of the confounding factors in the development of late restenosis after coronary stenting.

Action potential bursts in central snail neurons elicited by d-amphetamine: roles of ionic currents

The roles of the ionic currents in the firing of potential bursts elicited by d-amphetamine in central snail neurons were studied in the identified RP4 neuron of the African snail, Achatina fulica Ferussac, using the two-electrode voltage-clamp method. Oscillations of membrane potential bursts were elicited by d-amphetamine. The action potential bursts elicited by d-amphetamine decreased following intracellular injection of either EDTA or magnesium, or extracellular application of lanthanum. Voltage-clamped studies revealed that d-amphetamine decreased the fast Na(+), Ca(2+) and transient outward K(+) currents of the RP4 neuron. It also decreased the steady-state K(+) current and elicited a negative slope resistance in the steady-state I-V curve between -50 and -10 mV. The amplitude of negative slope resistance was decreased if either Na(+)-free saline or Co(2+)-substituted Ca(2+)-free saline was perfused. d-Amphetamine did not increase the amplitude of the slowly inactivating Ca(2+) current or the persistent Na(+) currents of RP4 neuron. Tetraethylammonium, a blocker of the delayed outward K(+) current, elicited action potential bursts and negative slope resistance in the RP4 neuron, while 4-aminopyridine, an inhibitor of transient outward K(+) current (I(A)), did not. These results demonstrate that the delayed outward K(+) current and the negative slope resistance in steady-state I-V curve elicited by d-amphetamine may be responsible for the action potential bursts in central snail neurons elicited by d-amphetamine.

Differentiation status modulates transcription factor NF-kappaB activity in unstimulated human hepatocellular carcinoma cell lines

We report herein a novel finding that under an unstimulated condition, a group of four human hepatocellular carcinoma (HCC) cell lines with varying degrees of differentiation, can spontaneously activate NF-KB. The propensity of activation coincided inversely with the differentiation status, with order being SK-Hep-1 > J5 > Hep3B > HepG2. Further studies indicate that this pattern of activation correlates excellently with the descending order of intracellular GSH/GSSG ratios as well as with the ascending order in the ability of these cells to generate hydrogen peroxide. Taken together, our data suggest that differentiation status may play a pivotal role in modulating intracellular thiol redox status and the extent of catalase expression, which may be crucial in the control of NF-kappaB activity in these HCC cells.

Hepatitis B virus core protein interacts with the C-terminal region of actin-binding protein

Hepatitis B viral core protein is present in the nucleus and cytoplasm of infected hepatocytes. There is a strong correlation between the intrahepatic distribution of core protein and the viral replication state and disease activity in patients with chronic hepatitis. To understand the role of core protein in the pathogenesis of HBV, we used a yeast two-hybrid system to search for cellular proteins interacting with the carboxyl terminus of core protein, as this region is involved in a number of important functions in the viral replication cycle including RNA packaging and DNA synthesis. A cDNA encoding the extreme C-terminal region of human actin-binding protein, ABP-276/278, was identified. This interaction was further confirmed both in vitro and in vivo. In addition, the extreme C-terminal region of ABP-276/278 interacted with the nearly full-length HBV core protein. Since this region is present in both the core and the precore proteins, it is likely that both core and precore proteins of HBV can interact with the C-terminal region of ABP-276/278. The minimal region of ABP-276/278 which interacted with the HBV core protein was the C-terminal 199 amino acid residues which correspond to part of the 23rd repeat, the entire 24th repeat and the intervening hinge II region in ABPs. The potential functional outcome of ABP interaction in HBV replication and its contribution to the pathological changes seen in patients with chronic HBV infection are discussed.

[Studies on technology of supercritical-CO2 fluid extraction for volatile oils and saikosaponins in Bupleurum chinense DC]

OBJECTIVE

To study the technology of supercritical-CO2 fluid extraction (SFE-CO2) for the volatile oils and saikosaponins in Bupleurum chinense.

METHOD

Exploring the effects of pressure, temperature, extraction time, flow rate of CO2 and entrainers on the yield of the oils and saikosaponin-contained extracts; determining the optimum conditions for SFE-CO2; analyzing the oils by GC/MS and comparing the technology of SFE-CO2 with that of traditional steam distillation.

RESULT

The optimum extraction conditions turned out to be--for volatile oils: pressure (EP) = 20 MPa, temperature (ET) = 30 degrees C, isolator I pressure (1P-I) = 12 MPa, temperature(1T-I) = 65 degrees C, isolator II pressure (1P-II) = 6 MPa, temperature (1T-II) = 40 degrees C, extraction time = 4 hours, and CO2 flow rate = 10-20 kg.(h.kg)-1 crude drug; for saikosaponins: EP = 30 MPa, ET = 65 degrees C, 1P I = 12 MPa, 1T I = 55 degrees C, 1P II = 6 MPa, 1T II = 43 degrees C, extraction time = 3 hours, entrainer = 60% ethanol, and CO2 flow rate = 20-25 kg.(h.kg)-1 crude drug.

CONCLUSION

SFE-CO2 excels the traditional steam distillation in raising yield and reducing extraction time. The oils are composed of 22 constituents including caproaldehyde, and the saikosaponins can only be extracted with the help of entrainers under higher pressure and temperature.

Expression and regulation of alkaline phosphatases in human breast cancer MCF-7 cells

The effect of retinoic acid and dexamethasone on alkaline phosphatase (AP) expression was investigated in human breast cancer MCF-7 cells. Cellular AP activity was induced significantly by retinoic acid or dexamethasone in a time-dependent and dose-dependent fashion. A marked synergistic induction of AP activity was observed when the cells were incubated with both agents simultaneously. Two AP isozymes, tissue-nonspecific (TNAP) and intestinal (IAP), were shown to be expressed in MCF-7 cells as confirmed by the differential rate of thermal inactivation of these isozymes and RT-PCR. Based on the two-isozyme thermal-inactivation model, the specific activities for TNAP and IAP in each sample were analyzed. TNAP activity was induced only by retinoic acid and IAP activity was induced only by dexamethasone. Whereas dexamethasone conferred no significant effect on TNAP activity, retinoic acid was shown to inhibit IAP activity by approximately 50%. Interestingly, TNAP was found to be the only isozyme activity superinduced when the cells were costimulated with retinoic acid and dexamethasone. Northern blot and RT-PCR analysis were then used to demonstrate that the steady-state TNAP mRNA level was also superinduced, which indicates that the superinduction is regulated at the transcriptional or post-transcriptional levels. In the presence of the glucocorticoid receptor antagonist RU486, the dexamethasone-mediated induction of IAP activity was blocked completely as expected. However, the ability of RU486 to antagonize the action of glucocorticoid was greatly compromised in dexamethasone-mediated superinduction of TNAP activity. Furthermore, in the presence of retinoic acid, RU486 behaved as an agonist, and conferred superinduction of TNAP gene expression in the same way as dexamethasone. Taken together, these observations suggest that the induction of IAP activity by dexamethasone and the superinduction of TNAP by dexamethasone were mediated through distinct regulatory pathways. In addition, retinoic acid plays an essential role in the superinduction of TNAP gene expression by enabling dexamethasone to exert its agonist activity, which otherwise has no effect.

Identification of the sites of hydroxyl radical reaction with peptides by hydrogen/deuterium exchange: prevalence of reactions with the side chains

Hydroxyl radical-effected protium/deuterium ((1)H/(2)H) exchange into the C-H bonds present in peptides has been used to identify the site of hydrogen atom abstraction by hydroxyl radical. Radiolysis of anaerobic, N(2)O-saturated D(2)O solutions containing peptide and dithiothreitol generates a hydroxyl radical that mediates (1)H/(2)H exchange into the side chains of peptides of up to 66 atom % excess (2)H. The (1)H/(2)H exchange is determined by measuring the isotope ratio, [M + H + 1](+)/[M + H](+), of the peptide using electrospray ionization-mass spectrometry. The (1)H/(2)H exchange within each residue of the peptide was determined by measuring the isotope ratio of each isolated dansyl amino acid following hydrolysis and derivatization. Generation of 0.40 mM hydroxyl radical effected (1)H/(2)H exchange into each of the five different residues of (Ala(2))-leucine enkephalin (YAGFL). The propensity of the residues to undergo exchange was L > Y > A congruent with F > G, independent of whether they were radiolyzed separately or as the peptide. The minimal exchange into glycine suggests that reaction of hydroxyl radical with the side chain hydrogens predominates over reaction with the polypeptide alpha-hydrogens. The ability of radiolysis to effect (1)H/(2)H exchange into a larger peptide, SNEQKACKVLGI, was also demonstrated.

Epitope-vaccine induces high levels of ELDKWA-epitope-specific neutralizing antibody

Based on the fact that mAb 2F5 recognizing ELDKWA-epitope on the C-domain of HIV-1 gp41 has significant neutralization potency against 90% of the investigated viruses of African, Asian, American and European strains, we attempted to characterise immunogenicity of the ELDKWA-epitope on an epitope-vaccine, and to produce ELDKWA-epitope-specific monoclonal antibodies (mAb) induced by the epitope-vaccine. The C-domain peptide (P2) and the ELDKWA-tetramer peptide [C-(ELDKWAG)4] were conjugated with BSA or P24-EC (GPKEPFRDYVDRFYK, a peptide of HIV-1 gag-protein P24, proved to be a good carrier peptide to induce an immune response to the hapten on the conjugates[18])by different methods. After the vaccination course, two P2-BSA peptide-vaccines both induced a strong antibody response against the P2-peptide by about 1:12800-25600 dilution, and a weak antibody response against the ELDKWA-epitope (1:1600-3200). The P2-P24EC and P2 (conjugated with itself) peptide-vaccines could also induce a weak antibody response against the ELDKWA-epitope (1:1600-3200), while an rgp160 subunit vaccine induced a very weak antibody response (1:400). Interestingly, the ELDKWA-tetramer epitope-vaccine [C-(ELDKWAG)4-BSA] could induce a strong antibody response against the ELDKWA-epitope (1:12800-25600), i.e. It increased the level of ELDKWA-antibody eight-fold, clearly better than the P2 peptide-vaccine, and much better than the rgp160 subunit vaccine, which indicates that the immunogenicities of the ELDKWA-epitope on the ELDKWA-tetramer peptide, the C-domain peptide and rgp160 are very different. These results suggest that the ELDKWA-epitope-vaccine may be a new strategy for inducing high levels of epitope-specific neutralizing antibodies against HIV-1. Using hybridoma-technique, a mouse monoclonal antibody recognizing the ELDKWA-epitope on ELDKWA-peptide and C-domain peptide was produced by immunization with the C-(ELDKWAG)4-BSA epitope-vaccine, which indicates a new way to produce an epitope-specific mAb, namely immunization with epitope-vaccine instead of a natural or recombinant protein immunogen.

Association between aminolevulinate dehydrogenase genotype and blood lead levels in Taiwan

This study was designed to evaluate the association between the aminolevulinate dehydrogenase (ALAD) genotype and blood lead levels in a general population environmentally exposed to lead. This study population of 660 subjects was secondarily sampled from the 3000 random samples of Taiwanese general population to study the distribution of blood lead levels in the Taiwanese population. A simple assay based on the polymerase chain reaction-restriction fragment length polymorphism technique was used to determine the genotype of the ALAD gene. This study found that most of the Taiwanese population was ALAD 1-1 (95.4%). Only 4.6% (30 subjects) of population were found to be 1-2 or 2-2. It has been hypothesized that the ALAD2 allele is associated with increased absorption of lead. This study found that individuals with ALAD2 alleles had 20% higher blood lead levels than persons with ALAD1 alleles (7.83 +/- 5.95 vs 6.51 +/- 5.03 micrograms/dL). However, the difference was not statistically significant, even after adjustment for other risk factors of environmental exposure. The result supports the previous finding that individuals with ALAD2 allele had higher blood lead levels. The small sample size and large amount of variation in our study may account for the insignificant association.

Antibodies to HIV-1 gp41 recognize synthetic peptides of human IFN-alpha and IFN-beta

Based on our finding that a common epitope exists between HIV-1 gp41 and human type I interferons (IFN-alpha and IFN-beta), and increased levels of antibodies against human IFN-alpha and IFN-beta were observed in HIV-1-infected individuals, we tried to explain the mechanism of increased levels of antibodies. Mouse antisera recognizing HIV-1 recombinant soluble (rs) gp41 (aa 539-684) interacted with two synthetic peptides sequence-corresponding to the IFN-alpha/beta receptor binding site on human IFN-alpha and IFN-beta, while normal mouse serum (pooled normal sera) did not. The anti-rspg41 antisera after adsorption by IFN-beta sepharose column lost the activity of interaction with both synthetic peptides. In another experiment, rsgp41 could bind to sepharose column conjugated with anti-IFN-beta polyclonal antibodies (IgG). These results indicate that the common epitope on gp41 and type I interferons could induce antibodies recognizing the receptor binding site on IFN-alpha and IFN-beta, suggesting that increased levels of antibodies against IFN-alpha and IFN-beta in HIV-1-infected individuals could be induced by gp41.

Soft neurological signs in schizophrenic patients and their nonpsychotic siblings

This study examined neurological signs as familial vulnerability factors to schizophrenia. Fifteen Chinese schizophrenic patients, 21 of their nonpsychotic siblings, and 26 healthy volunteers, matched for age, sex, and education, were assessed by using the Cambridge Neurological Inventory. Results showed that patients and their siblings had significantly higher global neurological impairment than controls. The severity of motor coordination impairment of the siblings was in between patients and controls. This may suggest either patients have higher genetic vulnerability for the neurological abnormality and schizophrenia than their nonpsychotic siblings or the disease can further worsen the preexisting neurological deficit. Disinhibition signs were similar in patients and siblings, but significantly less in controls indicating its familial nature. Extrapyramidal and sensory integration signs were similar in siblings and controls, but significantly more severe in patients, suggesting nonfamilial abnormalities. In conclusion, these findings may imply different etiological origins for different subgroups of neurological signs.

Thresholding using two-dimensional histogram and fuzzy entropy principle

This paper presents a thresholding approach by performing fuzzy partition on a two-dimensional (2-D) histogram based on fuzzy relation and maximum fuzzy entropy principle. The experiments with various gray level and color images have demonstrated that the proposed approach outperforms the 2-D nonfuzzy approach and the one dimensional (1-D) fuzzy partition approach.

Analysis of DNA fragments by microchip electrophoresis fabricated on poly(methyl methacrylate) substrates using a wire-imprinting method

Microfluidic devices were fabricated on poly(methyl methacrylate) (PMMA) substrate using two small-diameter (79 microm) wires to create a cross impression in plastics softened by low-temperature heating. The resulting channels had a rounded shape and 75 microm in depth. The variability of the channel dimensions was found to be less than 6% from different locations of the same channel and less than 10% between chips. Moreover, the fabricated PMMA chip appeared to sustain an electric field strength up to 300 V/cm without significant Joule heating. The function of resulting devices for electrophoretic injection and separation of a DNA size marker, HaeIII digest of (phiX174, was also characterized. Results indicated that all of the 11 DNA fragments of the size marker could be identified in less than 3 min with relative standard deviations less than 0.4% and 8% for migration time and peak area, respectively. Moreover, with the use of near infrared (IR) dye, fluorescence signals of the higher molecular weight fragments (> 603 bp in length) could be detected at total DNA concentrations as low as 0.1 microg/mL (S/N = 4.2). In conclusion, the performance of wire-imprinted devices on PMMA substrate were comparable to those fabricated by other professional means.

Effect of metallothionein on tolerance of nitroglycerin in rats

AIM

To assess whether metallothionein (Met) could improve the nitroglycerin tolerance in vivo.

METHODS

Nitrate tolerance was induced by 2-d treatment of nitroglycerin (Nit) patch (0.05 mg.h-1). Endogenous Met production was induced by pretreatment of ZnCl2 and coadministration of intravenous Met (15 mg.kg-1.d-1) 2 d with Nit in tolerant rats. The induction of Met production was confirmed by the assay of liver and plasma Met levels.

RESULTS

ZnCl2 induced large amount of endogenous Met production in liver and plasma in Nit + ZnCl2 group than that in control group, (89 +/- 4) micrograms/g tissue vs (11.0 +/- 2.4) micrograms/g tissue in liver, P < 0.01, and in plasma (85 +/- 6) micrograms.L-1 vs (71 +/- 6) micrograms.L-1, P < 0.01. There was no significant difference in plasma Met levels in Nit and control groups [(75 +/- 6) micrograms.L-1 vs (71 +/- 6) micrograms.L-1, P > 0.05]. The endogenous Met production enhanced the hypotensive response in Nit + ZnCl2 group [(15.7 +/- 0.8) kPa vs (11.5 +/- 0.6) kPa, n = 6, P < 0.05]. The maximal vessel relaxation induced by sodium nitroprusside (SNP) was the same in 4 different groups but the highest EC50 (concentration which produces 50% of the maximal response to SNP) was found in tolerant group [(42 +/- 9) nmol.L-1, P < 0.01].

CONCLUSION

Exogenous Met or induction of endogenous Met production antagonize the development of Nit tolerance.

HIV-2 transmembrane protein gp36 binds to the putative cellular receptor proteins P45 and P62

Based on the findings that two cellular proteins of 45 kDa (P45) and 62 kDa (P62) serve as the putative receptor molecules for binding of HIV-1 transmembrane protein gp41 to human T, B lymphocytes and monocytes, we examined whether HIV-2 gp36 and HIV-1 gp41 share the putative receptor proteins P45 and P62. In SPR-assay (SPR: surface plasmon resonance), the recombinant soluble gp36 (rsgp36: Env aa518-678 from clone ROD) like the recombinant soluble gp41 (rsgp41: Env aa539-684 from clone BH10) was binding to P45 and P62. By affinity capillary electrophoresis (ACE)-analysis, formation of stable rsgp36-P45 and rsgp36-P62 complexes were confirmed, and the interactions of rsgp36 with P45 and P62 is quite strong with a fast association rate and a slow dissociation rate. These results indicate that HIV-2 gp36 and HIV-1 gp41 have the common putative cellular receptor proteins P45 and P62, and the binding of gp36 to human lymphocytes and monocytes could be based on the interaction between gp36 and P45 and P62.

Epitope-vaccines: a new strategy to induce high levels of neutralizing antibodies against HIV-1

Based on the experimental evidence that gp120 subunit vaccine did not protect individuals from HIV-1 infection, we suggested that epitope-vaccines of HIV-1 gp41 may be a new strategy to induce high levels of neutralizing antibodies against HIV-1, and characterised immunogenicity of epitope-vaccines. Two epitopes, RILAVERYLKD-epitope (aa586-596) on the N-domain and ELDKWA-epitope (aa669-674) on the C-domain of gp41, were demonstrated by us and others to induce protective activity. After vaccination course, the RILAVERYLKD-dimer epitope-vaccine [C(RILAVERYLKDG)2-BSA] induced strong epitope-specific antibody response by about 1:25,600 dilution, and the ELDKWA-tetramer epitope-vaccine [C-(ELDKWAG)4-BSA] could yet induce strong antibody response to ELDKWA-epitope by 1:12,800-25,600 dilution of antisera in mice, while rgp41 subunit vaccine induced very weak antibody response to both epitopes (1:400). In rabbit experiments, the titres of ELDKWA-epitope-specific antibody induced by ELDKWA-epitope-vaccine [C-(ELDKWAG)4-BSA] reached to 1:6,400, while rgp41 subunit vaccine induced very weak antibody response to this epitope and to P1 and P2 peptides (1:400). Moreover, the ELDKWA-epitope-specific antibodies in mice and rabbit antisera induced by epitope-vaccine could very strongly interact with P2 peptide sequence-corresponding to the C-domain of gp41 (dilution by 1:25,600), and the RILAVERYLKD-epitope-specific antibodies in mice antisera induced by epitope-vaccine could also very strongly interact with P1 peptide sequence-corresponding to the N-domain of gp41 (dilution by 1:102,400). All these results provided experimental evidence that epitope-vaccine may be a new general strategy to induce high levels of neutralizing antibodies against HIV-1 or other viruses.

Immunogenicity of neutralizing epitopes on multiple-epitope vaccines against HIV-1

Based on our hypothesis that epitope vaccine may be a new strategy to induce high levels of neutralization antibodies against HIV-1, we prepared multiple-epitope vaccines using three neutralizing epitopes (GPGRAFY, RILAVERYLKD and ELDKWA) of HIV-1 gp160, and characterized their immunogenicity. Peptide 1 [C-G-(ELDKWA-GPGRAFY)(2)-K] and peptide 2 (CG-GPGRAFY-ELDKWA-G-RILAVERYLKD) were synthesized and conjugated with carrier protein bovine serum albumin (BSA). After vaccination antibody responses to these immunogens were induced and evaluated by ELISA. The C-G-(ELDKWA-GPGRAFY)(2)-K-BSA (BSA: carrier protein) multiple-epitope vaccine induced a strong antibody response to the C-G-(ELDKWA-GPGRAFY)(2)-K peptide (antibody titer: 1:25,600) and C-(ELDKWAG)(4) peptide (antibody titer: 1:12,800), but a weak antibody response to the C-(GPCGRAFY)(4) peptide. The CG-GPGRAFY-ELDKWA-G-RILAVERYLKD-K-BSA (BSA: carrier protein) multiple-epitope vaccine also induced strong antibody response to the CG-GPGRAFY-ELDKWA-G-RILAVERYLKD-K peptide (antibody titer: 1:25, 600) and C-(ELLDKWAG)(4) peptide (antibody titer: 1:6,400), a very strong response to C-(RIVALVERYLKD-G)(2)-K peptide (dilution: 1:102, 400), and a very weak response to the C-(GPGRAFY)(4) peptide (dilution: 1:400) in mice. Both antisera induced by both multiple-epitope vaccines interacted with the recombinant soluble gp41 (rgp41), but did not bind two control peptides. In comparison with both epitope vaccines, the rgp160 subunit vaccine could induce weak epitope-specific antibody response to these three epitopes on the three epitope peptides and V3, N-domain and C-domain peptides (dilution: 1:400-1:1,600). These results indicate that both multiple-epitope vaccines could induce high levels of antibodies to both neutralizing epitopes RILAVERYLKD and ELDKWA, while the GPGRAFY epitope on both vaccines appeared to have weak immunogenicity. Both multiple-epitope vaccines showed significant potency on inducing high levels of epitope-specific neutralization antibodies in comparison with rgp160 subunit vaccine.

Safety and efficacy of the platelet glycoprotein IIb/IIIa inhibitor abciximab in Chinese patients undergoing high-risk angioplasty

BACKGROUND

Platelets are believed to play a role in the ischemic complications of coronary angioplasty, such as abrupt closure of coronary vessels during or soon after the procedure. Accordingly, we evaluated the effect of a chimeric monoclonal antibody abciximab, directed against the platelet glycoprotein IIb/IIIa receptor, in patients undergoing angioplasty who were at high risk for ischemic complications. This receptor is the final common pathway for platelet aggregation.

METHODS

In a prospective, double-blind trial, we randomly assigned 42 patients to receive a bolus and an infusion of placebo or a bolus and an infusion of abciximab. Low-dose, weight-adjusted heparin (initial dose of 70 U/kg of body weight) was used in both groups. Patients underwent coronary angioplasty for high-risk clinical situations involving unstable angina or high-risk coronary morphologic characteristics. The primary study end-point consisted of any of the following: death, nonfatal myocardial infarction, unplanned surgical revascularization, unplanned repeat percutaneous procedure, unplanned implantation of a coronary stent, or insertion of an intra-aortic balloon pump for refractory ischemia within 30 days of randomization.

RESULTS

Compared with placebo, the abciximab resulted in a trend toward reduction in periprocedural myocardial infarction from 15% to 0%, although the differences were not statistically significant (p = 0.099). There were no significant differences between the two groups in the risk of major and minor bleeding and the need for blood transfusion.

CONCLUSIONS

Inhibition of platelet glycoprotein IIb/IIIa receptor with abciximab, together with low-dose, weight-adjusted heparin, had a favorable trend toward the reduction of periprocedural myocardial infarction in patients undergoing high-risk angioplasty, without increasing the risk of hemorrhage.

Acute fatal vasoplegia and asystole induced by intravenous amiodarone after cardiopulmonary bypass in a patient with preoperative cardiogenic shock

Single dose intravenous amiodarone has been widely used and shown to be effective to treat supraventricular and ventricular arrhythemias in cardiac surgery. We, herein, report a 60-year-old female patient, sustaining cardiogenic shock in the course of percutaneous transluminal coronary angioplasty (PTCA) for unstable angina unrelieved by medication including nitroglycerin, succumbed to a life-saving emergent coronary artery bypass grafting (CABG) operation at the end of cardiopulmonary bypass (CPB) following a 180 mg bolus dose of amiodarone (3 mg/kg) directed at the ventricular arrhythmias, triggered by protamine and unresponsive to lidocaine treatment. Amiodaroneinduced asystole and vasoplegia were thought to be the causation of the failure of resuscitation. The causes of the development of these complications, the potential hazards of its use and the management relative to the consequential complications are reviewed and discussed.

Stereoselective determination of trihexyphenidyl in human serum by LC-ESI-MS

The antiparkinsonian drug trihexyphenidyl (THP) is currently manufactured and administered as a racemate. However, stereochemistry can play significant role in the drug's pharmacokinetics, biotransformation, metabolism, interaction with cellular and tissue components and overall effect on human body. It is necessary to consider such a drug as a mixture of two compounds (drug enantiomers), with their own effect on the human body. The present paper describes a simple and sensitive LC-MS method for the stereoselective determination of THP in human serum. In this study, the sample was prepared by a solid-phase extraction (SPE) procedure. The enantiomer separation was done using native beta-cyclodextrin stationary phase LC column. The combination of ESI-MS detection and SPE showed excellent sensitivity and selectivity of the method. The limits of detection of <0.1 ng/ml can be easily achieved, which is 7,000 times lower than the detection limits achievable by a UV detection method. The method has at least a 3-order of magnitude linear dynamic range for both enantiomers (concentrations up to 1,323 ng/ml were tested). This is 24 times wider than the therapeutic range of THP (peak THP plasma concentration of 55 ng/ml was previously reported). The recoveries of THP enantiomers from the human serum were > 95%.

Plastic microchip electrophoresis for analysis of PCR products of hepatitis C virus

BACKGROUND

Electrophoresis on polymeric rather than glass microstructures is a promising separation method for analytical chemistry. Assays on such devices need to be explored to allow assessment of their utility for the clinical laboratory.

METHODS

We compared capillary and plastic microchip electrophoresis for clinical post-PCR analysis of hepatitis C virus (HCV). For capillary electrophoresis (CE), we used a separation medium composed of 10 g/L hydroxypropyl methyl cellulose in Tris-borate-EDTA buffer and 10 micromol/L intercalating dye. For microchip electrophoresis, the HCV assay established on the fused silica tubing was transferred to the untreated polymethylmethacrylate microchip with minimum modifications.

RESULTS

CE resolved the 145-bp amplicon of HCV in 15 min. The confidence interval of the migration time was <3.2%. The same HCV amplicon was resolved by microchip electrophoresis in <1.5 min with the confidence interval of the migration time <1.3%.

CONCLUSION

The polymer microchip, with advantages that include fast processing time, simple operation, and disposable use, holds great potential for clinical analysis.

Upregulation of a silent sodium channel after peripheral, but not central, nerve injury in DRG neurons

After transection of their axons within the sciatic nerve, DRG neurons become hyperexcitable. Recent studies have demonstrated the emergence of a rapidly repriming tetrodotoxin (TTX)-sensitive sodium current that may account for this hyperexcitability in axotomized small (<27 microm diam) DRG neurons, but its molecular basis has remained unexplained. It has been shown previously that sciatic nerve transection leads to an upregulation of sodium channel III transcripts, which normally are present at very low levels in DRG neurons, in adult rats. We show here that TTX-sensitive currents in small DRG neurons, after transection of their peripheral axonal projections, reprime more rapidly than those in control neurons throughout a voltage range of -140 to -60 mV, a finding that suggests that these currents are produced by a different sodium channel. After transection of the central axonal projections (dorsal rhizotomy) of these small DRG neurons, in contrast, the repriming kinetics of TTX-sensitive sodium currents remain similar to those of control (uninjured) neurons. We also demonstrate, with two distinct antibodies directed against different regions of the type III sodium channel, that small DRG neurons display increased brain type III immunostaining when studied 7-12 days after transection of their peripheral, but not central, projections. Type III sodium channel immunoreactivity is present within somata and neurites of peripherally axotomized, but not centrally axotomized, neurons studied after <24 h in vitro. Peripherally axotomized DRG neurons in situ also exhibit enhanced type III staining compared with control neurons, including an accumulation of type III sodium channels in the distal portion of the ligated and transected sciatic nerve, but these changes are not seen in centrally axotomized neurons. These observations are consistent with a contribution of type III sodium channels to the rapidly repriming sodium currents observed in peripherally axotomized DRG neurons and suggest that type III channels may at least partially account for the hyperexcitibility of these neurons after injury.