Mesenchymal stem cell-based angiopoietin-1 gene therapy for acute lung injury induced by lipopolysaccharide in mice

Bone marrow-derived mesenchymal stem cells (MSCs) can serve as a vehicle for gene therapy. Angiopoietin-1 (Ang1) is a critical factor for endothelial survival and vascular stabilization via the inhibition of endothelial permeability and leukocyte-endothelium interactions. We hypothesized that MSC-based Ang1 gene therapy might be a potential therapeutic approach for lipopolysaccharide (LPS)-induced lung injury. MSCs were isolated from 6 week-old inbred male mice and transduced with the Ang1 gene, using a lentivirus vector. The MSCs showed no significant phenotypic changes after transduction. In the in vivo mouse model, the LPS-induced lung injury was markedly alleviated in the group treated with MSCs carrying Ang1 (MSCs-Ang1), compared with groups treated with MSCs or Ang1 alone. The expression of Ang1 protein in the recipient lungs was increased after MSCs-Ang1 administration. The histopathological and biochemical indices of LPS-induced lung injury were improved after MSCs-based Ang1 gene treatment. MSCs-Ang1 administration also reduced pulmonary vascular endothelial permeability and the recruitment of inflammatory cells into the lung. Cells of MSC origin could be detected in the recipient lungs for 2 weeks after injection with MSCs. These results suggest that MSCs and Ang1 have a synergistic role in the treatment of LPS-induced lung injury. MSC-based Ang1 gene therapy may be developed as a potential novel strategy for the treatment of acute lung injury.

Tribo-mechanical properties of thin boron coatings deposited on polished cobalt alloy surfaces for orthopedic applications

This paper presents experimental evidence that thin (< approximately 200 nm) boron coatings, deposited with a (vacuum) cathodic arc technique on pre-polished Co-Cr-Mo surfaces, could potentially extend the life of metal-on-polymer orthopedic devices using cast Co-Cr-Mo alloy for the metal component. The primary tribological test used a linear, reciprocating pin-on-disc arrangement, with pins made of ultra-high molecular weight polyethylene. The disks were cast Co-Cr-Mo samples that were metallographically polished and then coated with boron at a substrate bias of 500 V and at about 100 degrees C. The wear tests were carried out in a saline solution to simulate the biological environment. The improvements were manifested by the absence of a detectable wear track scar on the coated metal component, while significant polymer transfer film was detected on the uncoated (control) samples tested under the same conditions. The polymer transfer track was characterized with both profilometry and Rutherford Backscattering Spectroscopy. Mechanical characterization of the thin films included nano-indentation, as well as additional pin-on-disk tests with a steel ball to demonstrate adhesion, using ultra-high frequency acoustic microscopy to probe for any void occurrence at the coating-substrate interface.

Airway hyperresponsiveness induced by repetitive intraperitoneal injection of lipopolysacharide and the involvement of inflammation and nitric oxide in guinea pigs

OBJECTIVE

Airway hyperresponsiveness (AHR) is involved in bronchial asthma and chronic obstructive pulmonary disease (COPD) and produces respiratory symptoms. Lipopolysaccharide (LPS) has been found to be significantly related to the severity of asthma. However, its clinical mechanism still remains controversial. This study investigated the in vivo effect of repetitive intraperitoneal administration of lipopolysaccharide (LPS) on airway hyperresponsiveness (AHR) in guinea pigs and the possible involvement of inflammation, nitric oxide (NO) and nitric oxide synthase (NOS).

METHODS

There were two exposure groups for intraperitoneal LPS injection: (1) LPS was given at a dose of 1 mg x kg(-1), followed by sterile saline (NS) 1 ml x kg(-1) 8 h later every 24 h; (2) LPS was given at a dose of 0.5 mg x kg(-1) two times with an interval of 8 h every 24 h. Each exposure regime was repeated 4 times. Control animals were given NS and 6 naive guinea pigs were used as baseline control. Determinations were made 24 h after each exposure.

RESULTS

Persistent AHR occurred 24 h after the third and fourth exposures to LPS in the first exposure group (at one dose), but occurred earlier after the exposures to LPS in the second exposure group (at divided doses). The numbers of total cells and neutrophils were elevated initially but subsided subsequently in LPS-treated groups. No evidence of morphological changes in the small airways was found 24 h after any of the exposures. The Ca(2+)-dependent and Ca(2+)-independent NOS activities (mainly produced by iNOS) in the BALF, as well as the production of NO, were significantly elevated 24 h after any of third and fourth exposures in LPS-treated groups.

CONCLUSIONS

Our results demonstrate that repetitive intraperitoneal LPS can induce persistent AHR which occurs earlier when the frequency of injection increase, and an elevation of NO production and iNOS activity may be involved in is systemic-LPS-induced AHR.

Transient overexpression of gamma interferon promotes Aspergillus clearance in invasive pulmonary aspergillosis

Cytokines are critical molecules necessary for normal lung pathogen host defences. Gamma interferon (IFN-gamma) and T1-phenotype immune responses are important components of host defence against Aspergillus. Therefore, we hypothesized that transient overexpression of IFN-gamma within the lung could augment host immunity against Aspergillus. Here it was showed that intranasal administration of 5 x 10(7) colony-forming units (CFU) of Aspergillus fumigatus (Af ) induced the expression of IFN-gamma. Mice were intranasally (i.n) administrated with 5 x 10(8) PFU of a recombinant adenovirus vector containing the murine IFN-gamma cDNA (AdmIFN-gamma), and challenged 24 h later with Af. We observed that i.n. administration of AdmIFN-gamma resulted in about a fourfold increase in levels of IFN-gamma and IL-12 within the lung, about a 75% reduction in lung fungal contents at day 2 and a more than threefold higher survival rate in the AdmIFN-gamma-treated group compared to the controls (P < 0.01). This protection effect was not found when AdmIFN-gamma was i.p. administrated. Alveolar macrophages and lung leucocytes isolated from i.n. AdmIFN-gamma-treated animals displayed enhanced killing of intracellular Aspergillus organisms ex vivo. These results demonstrate that transient overexpression of IFN-gamma could augment host defence against Aspergillus.

Dendritic cells transduced with an adenovirus vector encoding interleukin-12 are a potent vaccine for invasive pulmonary aspergillosis

Invasive pulmonary aspergillosis (IPA) is a common and devastating pneumonia. We developed a novel antiinfective vaccine that couples the potent Ag-presenting capacity of dendritic cells (DCs) with paracrine delivery of interleukin-12 (IL-12) to local immune response sites. Our results showed that DCs engulfed Aspergillus conidia through coiling phagocytosis. Transfection of DCs with adenovirus encoding the cDNA of IL-12 did not affect their morphology and capacity to engulf conidia. The transduced DCs secreted IL-12, which was biologically active, to induce the production of gamma interferon (IFN-gamma) from spleen cells. Adoptive transfer of DCs pulsed with heat-inactivated Aspergillus fumigatus (HAF) to naive mice induced the Ag-specific production of IFN-gamma; the transduced HAF-pulsed DCs augmented this immune response further. Animals receiving HAF-pulsed DCs had lower fungal burdens, a more than three-fold higher survival rate at day 3. This protection was associated with a pronounced enhancement in the Aspergillus-specific IFN-gamma response. IL-12-engineered DCs augmented this protection strikingly as judged by a higher survival, and almost no Aspergillus could be detected in the lung of mice that had received IL-12-transduced HAF-pulsed DCs. These results suggest that antigen-pulsed DCs and IL-12 gene therapy could be used as adjunct therapy for aspergillosis.

Endotoxin tlerance inhibits lipopolysaccharide-initiated acute pulmonary inflammation and lung injury in rats by the mechanism of nuclear factor-kappaB

In this study, the effect of endotoxin tolerance on lipopolysaccharide (LPS)-initiated pulmonary inflammation, the local production of tumour necrosis factor-alpha (TNF-alpha) and the cytokine-induced neutrophil attractant (CINC), as well as the activation of nuclear factor-kappaB (NF-kappaB) and its subunit composition, were examined in vivo. Endotoxin tolerance was reproduced by four consecutive daily intraperitoneal injections of 0.6 mg/kg of Escherichia coli 055:B5 LPS. Compared with control rats, endotoxin-tolerant rats failed to increase the permeability of pulmonary microvascular or recruit neutrophil to lung tissue upon restimulation with 6 mg/kg of LPSs. Pretreatment with LPSs inhibited the protein level of TNF-alpha in bronchoalveolar lavage fluid (BALF) and mRNA expression of CINC in lung tissue in response to subsequent LPS stimulation. These changes were accompanied by the suppression of activation of NF-kappaB, including the low level of total amount of DNA-binding activity and high percentage of non-transactive p50 homodimers. These data demonstrate that endotoxin tolerance can alleviate the LPS-induced acute neutrophilic pulmonary inflammation in rats and can inhibit the proinflammatory cytokines in lung and suggest that endotoxin tolerance might result from the unresponsiveness of NF-kappaB and persistent high percentage of p50 homodimers. Therefore, the phenomenon of endotoxin tolerance might be used as a strategy for the prevention or treatment of LPS-associated acute respiratory distress syndrome in which excessive or dysregulated inflammation leads to acute lung injury.

[Establishment and identification of the monoepitopic monoclonal antibody of Plasmodium falciparum]

AIM

To prepare a monoepitopic monclonal antibody of Plasmoduim falciparum.

METHODS

According to the theory of protein structure, a peptide with 6-9 residues representting the antigenicity of the original histidine-rich protein II (HRP-II) of P. falciparum was synthesized and used to immunize BALB/c mice after purity identification by capillary electrophoresis.

RESULTS

Four hybridoma cell lines targeting a suitable peptide from pf HRP-II were obtained by using spleen embedment method and hybridoma technology.

CONCLUSION

It is the first report to prepare a monoepitopic monoclonal antibody against original protein by selecting a suitable peptide from the primary sequence of protein.

[Diagnosis of Falciparum malaria by immunochromatographic test]

AIM

To evaluate the applicability of rapid immunochromatographic test(ICT) for diagnosing falciparum malaria in outpatient clinics in endemic area.

METHODS

With thick blood smear method as control, ICT was used for the detection of P. falciparum.

RESULTS

The sensitivity and specificity of ICT in detecting P. falciparum was 94.7% and 90.3%, respectively. No cross-reaction with P. vivax was found (P > 0.05).

CONCLUSION

ICT is much more rapid and simple than thick blood smear method for the diagnosis of falciparum malaria, and can be applied in the outpatient clinics in endemic area.

Ischemia alters the electrical activity of pacemaker cells isolated from the rabbit sinoatrial node

The purpose of this study was to investigate the mechanisms responsible for ischemia-induced changes in spontaneous electrical activity. An ischemic-like Tyrode solution (pH 6.6) reversibly depolarized the maximum diastolic potential (MDP) and reduced the action potential (AP) overshoot (OS). We used SNARF-1, which is an indicator of intracellular pH (pH(i)), and perforated-patch techniques to test the hypothesis that acidosis caused these effects. Acidic but otherwise normal Tyrode solution (pH 6.8) produced similar effects. Basic Tyrode solution (pH 8.5) hyperpolarized the MDP, shortened the AP, and slowed the firing rate. In the presence of "ischemic" Tyrode solution, hyperpolarizing current restored the MDP and OS to control values. HOE-642, an inhibitor of Na/H exchange, did not alter pH(i) or electrical activity and did not prevent the effects of ischemic Tyrode solution or recovery after washout. Time-independent net inward current but not hyperpolarization-activated inward current was enhanced by ischemic Tyrode solution or by 30 microM BaCl(2), a selective blocker of inward-rectifying K currents at this concentration. The results suggest that 1) acidosis was responsible for the ischemia-induced effects but Na/H exchange was not involved, 2) the OS was reduced because of depolarization-induced inactivation of inward currents that generate the AP upstroke, and 3) reduction of an inward-rectifying outward K current contributed to the depolarization.

Insight into hepatocellular carcinogenesis at transcriptome level by comparing gene expression profiles of hepatocellular carcinoma with those of corresponding noncancerous liver

Human hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. In this work, we report on a comprehensive characterization of gene expression profiles of hepatitis B virus-positive HCC through the generation of a large set of 5'-read expressed sequence tag (EST) clusters (11,065 in total) from HCC and noncancerous liver samples, which then were applied to a cDNA microarray system containing 12,393 genes/ESTs and to comparison with a public database. The commercial cDNA microarray, which contains 1,176 known genes related to oncogenesis, was used also for profiling gene expression. Integrated data from the above approaches identified 2,253 genes/ESTs as candidates with differential expression. A number of genes related to oncogenesis and hepatic function/differentiation were selected for further semiquantitative reverse transcriptase-PCR analysis in 29 paired HCC/noncancerous liver samples. Many genes involved in cell cycle regulation such as cyclins, cyclin-dependent kinases, and cell cycle negative regulators were deregulated in most patients with HCC. Aberrant expression of the Wnt-beta-catenin pathway and enzymes for DNA replication also could contribute to the pathogenesis of HCC. The alteration of transcription levels was noted in a large number of genes implicated in metabolism, whereas a profile change of others might represent a status of dedifferentiation of the malignant hepatocytes, both considered as potential markers of diagnostic value. Notably, the altered transcriptome profiles in HCC could be correlated to a number of chromosome regions with amplification or loss of heterozygosity, providing one of the underlying causes of the transcription anomaly of HCC.

Synthesis and characterization of chiral N-O turns induced by alpha-aminoxy acids

Chiral alpha-aminoxy acids of various side chains were synthesized with high optical purity starting from chiral alpha-amino acids. The conformations of diamides 13a-e, 15, and 16 were probed by using NMR, FT-IR, and CD spectroscopic methods as well as X-ray crystallography. The right-handed turns with eight-membered-ring intramolecular hydrogen bonds between adjacent residues (called the N-O turns) were found to be preferred for D-aminoxy acid residues, and they were independent of the side chains. The rigid chiral N-O turns should have great potential in molecular design.

Alteration of surfactant proteins A and D in bronchoalveolar lavage fluid of Pneumocystis carinii pneumonia

OBJECTIVE

To understand the interaction between surfactant proteins and pneumocystis carinii pneumonia (PCP), and the impact of corticosteriods on surfactant proteins.

METHODS

We established rat models of PCP and bacterial pneumonia induced by subcutaneous injection of 25 mg cortisone acetate. At 8-12 wk, the bronchoalveolar lavage fluid (BALF) of rats was collected. Total nucleated cells of BALF were counted and differentiated, and the concentrations of surfactant protein A (SP-A) and surfactant protein D (SP-D) were measured by immunoblotting assay. The rats were divided into three immunosuppressive groups and a normal control group. Group I, normal control (n = 6), consisted of healthy SD rats; group II, negative control (n = 6), consisted of rats with cortisone acetate injection for over 8 wk without lung infection; group III, bacterial pneumonia (n = 11), rats were injected with cortisone acetate over 8 wk that resulted in bacterial pneumonia without other pathogens isolated; and group IV, PCP (n = 14), rats with injected cortisone acetate for 8-12 wk and developed PCP without other pathogens isolated.

RESULTS

Our results indicated that the total cell count in BALF in the negative control group was lower than that in the normal control group (P < 0.001). During PCP infection, the total cell count and the percentage of polymorphonuclearcytes (PMNs) in BALF were significantly increased (P < 0.01), but were lower than those in the bacterial pneumonia group. The concentration of SP-A of BALF in PCP (45.1 +/- 22.1 micrograms/ml) was significantly increased in comparison with that in the negative control (16.2 +/- 9.9 micrograms/ml, P < 0.05) and bacterial pneumonia groups (6.2 +/- 5.6 micrograms/ml, P < 0.001). We also found that the relative content of SP-D was significantly higher in PCP (24,249 +/- 4780 grey values) than that in the negative control (13,384 +/- 2887 grey values, P < 0.001) and that in bacterial pneumonia (11,989 +/- 2750 grey values, P < 0.001). SP-A and SP-D were also higher in the moderate to heavy group of PCP than those seen in the mild group (P < 0.01, P < 0.001). SP-A and SP-D were higher in the negative control group than those in the normal control group, but there was no significant difference between the 2 groups.

CONCLUSION

These results suggest that the concentrations of SP-A and SP-D in BALF are increased by pneumocystis carinii specific stimulation, but the alteration is not related to the corticosteriod usage.

[The effectiveness of prolene patch in hernia prevention following harvesting rectus abdominis myocutaneous flap]

OBJECTIVE

To investigate the effectiveness of polypropylene path (Prolene) in hernia prevention following harvesting of rectus abdominis is myocutaneous flap.

METHODS

From November 1999 to October 2000, Prolene patches were applied in 26 cases to repair the anterior rectus sheath following harvesting free rectus abdominis myocutaneous flap. Data concerning each case included size of rectus flap, defect of rectus sheath, size of patch used, wound healing and complications.

RESULTS

Prolene patch showed good biocompatibility with abdominal tissue. No foreign-body rejection occurred after operation. Seroma developed in 1 case, and was drained bedside without complication. All prolene patches healed well in the body during follow-up. Hernia formation and abdominal bulge were not observed.

CONCLUSION

Prolene patch is a satisfactory material for repair of the anterior rectus sheath after harvesting free rectus abdominis myocutaneous flap.

[Autotrophic denitrification of groundwater by electrochemical process]

An autotrophic denitrification process and its reactor for removing nitrate from groundwater was investigated in this paper. Using activated carbon fiber(ACF) as electrodes, the electrochemical reactions could produce hydrogen as the donor for autotrophic denitrification. In the process, nitrate was removed effectively and no accumulation of nitrite in the effluent. The results in this study proved that some key factors, such as the applied current density, flow rate of water, oxidation-reduction potential and the nitrate concentration in raw water, influenced the electrochemically denitrifying effect. When the concentration of NO3(-)-N was 28.8 mg/L in inlet water, the optimum applied density was 9 mA, the highest hydraulic load of the reactor was 35 ml/h, and the reactor performed a practical buffering capacity to pH. After applying electricity to the reactor for 1 h, the oxidation-reduction potential decreased to below--200 mA, so an adaptable reductive environment could be provided in the reactor for denitrification.

[Establishing a model of neutropenia rat with Pseudomonas aeruginosa pneumonia and a study on its inflammatory reaction]

OBJECTIVE

To establish an animal model and study the inflammatory reaction of P. Aeruginosa pneumonia in neutropenia rats. METHODS Fifty SD rats were randomly divided into two groups: drug-treated group and control CON group. Drug-treated group was given a combination regimen of cyclophosphamide (15 m x kg(-1) d(-1)) and cortisone acetate (100 mg x kg(-1) x d(-1)) for seven days,then both groups were intratracheally challenged with P. Aeruginosa (0.2 ml ATCC 27853 6 x 10(8) CFU/ml). Their blood, bronchial alveolar lavage fluid (BALF) and lung tissue were collected before and 3, 6, 9, 24 h after challenging. Cytological and bacteriological examinations were performed, histopathologic changes of lung tissue were observed. Total proteins (TP) of BALF and the wet/dry ratio (W/D) of lung tissue were determined.

RESULTS

(1) Compared with CON group, rats of drug-treated group showed obviously weight loss and thymus atrophy [(141 +/- 8) g] vs [(201 +/- 14) g], [(0.06 +/- 0.05) g] vs (0.40 +/- 0.10) g, P < 0.001], developed leukocytopenia [(0.9 +/- 0.3) x 10(9)/L] vs [(7.3 +/- 1.9) x 10(9)/L, P < 0.001] and the numbers of alveolar macrophage in BALF decreased significantly; (2) After PA challenging, drug-treated rats showed less activities, worse situations and higher mortality (10.8%) than CON group which recovered quickly and none of them died. PA was identified from samples of BALF and lung tissue, both groups developed inflammatory reaction at 6 - 9 h in high level. Pulmonary pathologic study revealed that polymorphonuclears response of drug-treated group was delayed and less serious than that of CON group [at 9 h, drug-treated group, (102 +/- 13)/HP vs CON group (291 +/- 20)/HP, P < 0.01], however, interstitial edema, capillary congestion and focal hemorrhages were more obvious; (3) After PA challenging especially at 6 - 9 h, W/D ratio and TP concentrations were significantly high in both groups than those of before [drug-treated group, W/D (9.2 +/- 1.3) vs (5.9 +/- 1.4) TP (1.59 +/- 0.83) mg/ml vs (0.19 +/- 0.07) mg/ml; CON group:W/D 7.2 +/- 2.5 vs 4.9 +/- 0.8,TP(0.42 +/- 0.16) mg/ml vs (0.13 +/- 0.04) mg/ml, P < 0.05], however the alterations were much greater in drug-treated group (P < 0.05). Alteration of TP concentration showed some correlation with numbers of polymorphonuclears in lung tissue of CON group (r = 0.926, P < 0.05), but not in drug-treated group (r = 0.58, P = 0.31).

CONCLUSION

It was indicated that there may be other mechanisms than polymorphonuclears infiltration contributing to the more severe lung injury in drug-treated group characterized as neutropenia.

Identification and determination of glucuronides and their aglycones in Erigeron breviscapus by liquid chromatography-tandem mass spectrometry

A novel, speedy and reliable LC-MS-MS method for the search, identification and quantitation of O-glycosides and their aglycones from plant resources was established by analyzing the extract of Erigeron breviscapus. The extract was directly infused to a triple-quadrupole MS-MS and major glucuronides in the extract were screened out with high confidence by a neutral loss scan for the loss of a gluconic acid. The identity of these glucuronides and their aglycones was further confirmed with LC-MS-MS. In addition to scutellarin, apigenin 7-O-glucuronide, quercetin-3-O-glucuronide and their aglycones that were previously reported by others, we also confirmed by LC-MS-MS that remarkable amount of baicalin, an isomer of apigenin 7-O-glucuronide, presented in the extract of this plant, which had not been reported before. A satisfying quantitation of three glucuronides was also made by LC-MS-MS.

Crack characterization using guided circumferential waves

This paper examines the propagation of guided circumferential waves in a hollow isotropic cylinder that contains a crack, with the goal of using these guided waves to both locate and size the crack. The crack is sized using a modified Auld's formula, which relates the crack's length to a reflected energy coefficient. The crack is then located by operating on the backscattered signal with a time-frequency digital signal processing (DSP) technique, and then comparing these results to those obtained if the cylinder is perfect. The guided circumferential waves are generated with a commercial finite element method (FEM) code. One objective of this work is to demonstrate the effectiveness of using sophisticated DSP techniques to describe the effect of scattering on dispersive waves, showing it is possible to characterize cracks systematically and accurately by quantifying this scattering effect. The results show that the need for high frequency signals to detect small cracks is significantly decreased by using these techniques.

Optical processing of light-induced autofluorescence for characterization of tissue pathology

We describe an optical processing method for characterizing tissue pathology that is based on principal-component analysis of light-induced autofluorescence. A set of optical spectral filters, which are related to the principal-component loading vectors, is designed to process the autofluorescence signal optically and to generate principal-component scores from the autofluorescence spectra. The scores are then correlated with the tissue pathology. An optical processing system is designed that uses the in vivo fluorescence spectra recorded from nasopharyngeal tissues. We demonstrate that the system can differentiate nasopharyngeal carcinoma from normal tissue with a high degree of sensitivity and specificity and that the optical filters used in the system can be manufactured.

[Telomerase activity in stool of patients with colorectal cancer]

OBJECTIVE

To probe into the method for screening colorectal cancer by the way of stool.

METHODS

Telomerase activity in the stool of patients with colorectal cancer was determined by PCR-TRAP.

RESULTS

The positive rate of telomerase activity in the stool of patients with colorectal cancer was 62.8%. Its sensitivity, specificity and positive predictive value were 62.8%, 95.7%, and 96.4%, respectively. Telomerase activity in stool was not obviously correlated with Duke's stage, lymphatic metastasis and tumor location. Telomerase activity was also found in the stool sample of a patient with colonic adenoma.

CONCLUSION

The determination of telomerase activity in the stool of patients with colorectal cancer contributes to the improvement of screening and diagnosis of colorectal cancer.

HCN2 overexpression in newborn and adult ventricular myocytes: distinct effects on gating and excitability

Ventricular pacemaker current (I(f)) shows distinct voltage dependence as a function of age, activating outside the physiological range in normal adult ventricle, but less negatively in neonatal ventricle. However, heterologously expressed HCN2 and HCN4, the putative molecular correlates of ventricular I(f), exhibit only a modest difference in activation voltage. We therefore prepared an adenoviral construct (AdHCN2) of HCN2, the dominant ventricular isoform at either age, and used it to infect neonatal and adult rat ventricular myocytes to investigate the role of maturation on current gating. The expressed current exhibited an 18-mV difference in activation (V(1/2) -95.9+/-1.9 in adult; -77.6+/-1.6 mV in neonate), comparable to the 22-mV difference between native I(f) in adult and neonatal cultures (V(1/2) -98.7 versus -77.0 mV). This did not result from developmental differences in basal cAMP, because saturating cAMP in the pipette caused an equivalent positive shift in both preparations. In the neonate, AdHCN2 caused a significant increase in spontaneous rate compared with control (88+/-5 versus 48+/-4 bpm). In adult, where HCN2 activates more negatively, the effect was evident only during anodal excitation, requiring significantly less stimulus energy than control (2149+/-266 versus 3140+/-279 mV. ms). Thus, ventricular maturational state influences the voltage dependence of expressed HCN2, resulting in distinct physiological impact of expressed channels in neonate and adult myocytes. The full text of this article is available at http://www.circresaha.org.

Determination of scutellarin in Erigeron breviscapus extract by liquid chromatography-tandem mass spectrometry

A quantitative assay for scutellarin by LC-MS-MS (negative ion mode) was developed. The scutellarin was extracted from dry Erigeron breviscapus. Significant ion suppression was observed, which could be eliminated by increasing the turboionspray interface temperature to 350 degrees C and by 1000-fold dilution of the extract with solvent. The calibration curve of scutellarin showed excellent linearity over a wide concentration range (0.01-100 microg/ml) (r=0.998), and the limit of detection was 15 pg/ml using a 10-microl injection volume. The analysis time was 4 min/sample.

Comparison of blood counts in venous, fingertip and arterial blood and their measurement variation

We compared routine blood pictures in venous, fingertip and arterial blood and their measurement variation. A pair of venous and fingertip blood samples were simultaneously collected from 24 volunteers, and another pair of venous and arterial samples from another 12 volunteers. The volunteers were healthy adults, aged 20-22 years, with males and females in equal numbers. Three aliquots of blood were taken from each person for three measurements of blood counts, including haemoglobin concentration and haematocrit, using an automatic haematology analyser. Compared to arterial blood, there was a significant increase of erythrocyte count (2.7%) and haematocrit (3.1%) in the venous blood. The total and large leucocyte counts were significantly higher (9.2% and 12.6%, respectively) in the fingertip blood than in the venous blood. There were a decreasing number of leucocytes in the fingertip blood with repeated sampling. The intermeasurement variation for total leucocyte or haemoglobin measurement was significantly larger as measured with the fingertip blood or arterial blood than with the venous blood. The intermeasurement coefficients of variation of haemoglobin (1.3%) and small leucocyte ratio or platelet (approximately 4.0%) measurements with venous and arterial blood were the smallest and largest, respectively. Volume of arterial plasma was diminished by 2-3% after microcirculation. Elevation of total leucocyte count in the fingertip blood was mainly due to the increase of granulocytes. Measurement with venous blood was of better precision than with fingertip or arterial blood.