Differences between karyotypically normal and abnormal human embryonic stem cells

OBJECTIVES

To compare different biological characteristics of human embryonic stem cells (HESCs) between those with normal and those with abnormal karyotype.

MATERIALS AND METHODS

Culture-adapted HESCs (chHES-3) with abnormal karyotype were compared with karyotypically normal cells, with regard to pluripotency and differentiation capacity, ultrastructure, growth characteristics, gene expression profiles and signalling pathways.

RESULTS

We found a new abnormal karyotype of HESCs. We observed that chHES-3 cells with normal and abnormal karyotypes shared similarities in expression markers of pluripotency; however, karyotypically abnormal chHES-3 cells had a tendency for differentiation towards ectoderm lineages and were easily maintained in suboptimal culturing conditions. Abnormal chHES-3 cells displayed relatively mature cell organelles compared to normal cells, and karyotypically abnormal chHES-3 cells had increased survival and population growth. Genes related to cell proliferation and apoptosis were up-regulated, but genes associated with genetic instability (p53, Rb, BRCA1) were down-regulated in the karyotypically abnormal cells.

CONCLUSION

Karyotypically abnormal chHES-3 cells had a more developed capacity for proliferation, resistance to apoptosis and less genetic stability compared to normal chHES-3 cells and may be an excellent model for studying and characterizing initial stages that determine transition of embryonic stem cells into cancer stem cells.

Protein phosphatase-1 regulates Akt1 signal transduction pathway to control gene expression, cell survival and differentiation

AKT pathway has a critical role in mediating signaling transductions for cell proliferation, differentiation and survival. Previous studies have shown that AKT activation is achieved through a series of phosphorylation steps: first, AKT is phosphorylated at Thr-450 by JNK kinases to prime its activation; then, phosphoinositide-dependent kinase 1 phosphorylates AKT at Thr-308 to expose the Ser-473 residue; and finally, AKT is phosphorylated at Ser-473 by several kinases (PKD2 and others) to achieve its full activation. For its inactivation, the PH-domain containing phosphatases dephosphorylate AKT at Ser-473, and protein serine/threonine phosphatase-2A (PP-2A) dephosphorylates it at Thr-308. However, it remains unknown regarding which phosphatase dephosphorylates AKT at Thr-450 during its inactivation. In this study, we present both in vitro and in vivo evidence to show that protein serine/threonine phosphatase-1 (PP-1) is a major phosphatase that directly dephosphorylates AKT to modulate its activation. First, purified PP-1 directly dephosphorylates AKT in vitro. Second, immunoprecipitation and immunocolocalization showed that PP-1 interacts with AKT. Third, stable knock down of PP-1alpha or PP-1beta but not PP-1gamma, PP-2Aalpha or PP-2Abeta by shRNA leads to enhanced phosphorylation of AKT at Thr-450. Finally, overexpression of PP-1alpha or PP-1beta but not PP-1gamma, PP-2Aalpha or PP-2Abeta results in attenuated phosphorylation of AKT at Thr-450. Moreover, our results also show that dephosphorylation of AKT by PP-1 significantly modulates its functions in regulating the expression of downstream genes, promoting cell survival and modulating differentiation. These results show that PP-1 acts as a major phosphatase to dephosphorylate AKT at Thr-450 and thus modulate its functions.

Risk factors of biliary complications following liver transplantation: retrospective analysis of a single centre

BACKGROUND

Despite improvements that have been achieved in surgical techniques and organ preservation, biliary complications remain one of the most serious morbidities following liver transplantation. However, factors related to biliary complications after liver transplantation are not completely understood. The objective of this study was to identify retrospectively possible risk factors of biliary complications following liver transplantation.

METHODS

Data on 279 patients who underwent liver transplantation between January 1999 and November 2005 were collected retrospectively. Selected variables from preoperative, intraoperative and postoperative data were first analysed using univariate logistic regression. Filtered factors with p<0.1 in the first step were further investigated to identify factors independently associated with biliary complications following liver transplantation.

RESULTS

The overall incidence of biliary complications was 22.6%. Multivariate regression revealed that biliary cirrhosis (p = 0.038), anhepatic phase time (p = 0.04), and incidence of hepatic artery abnormality (p = 0.001) after transplantation were factors that were significantly related to biliary complications. Use of a T tube for biliary reconstruction and living grafts were not associated with biliary complications following liver transplantation.

CONCLUSION

This study suggests that further technical refinement-namely, shortening the anhepatic phase duration, shielding the hepatic artery, and refining biliary duct reconstruction-can reduce the incidence of biliary complications following liver transplantation.

Estimation of standard liver volume for liver transplantation in the Chinese population

INTRODUCTION

The accurate assessment of standard liver volume (SLV) is necessary for the safety of both the donor and the recipient in living donor liver transplantation. However, the accuracy of SLV formulas relates to cohorts or races. This study examined the accuracy of a simple linear formula versus previous formulas of SLV for Chinese adults.

METHODS

Among 112 patients with normal liver, we created a new formula for SLV with stepwise regression analysis using the following variables: age, gender, body weight, body height, body mass index, and body surface area. The agreement between the actual liver volume (LV) and calculated LV using various formulas was prospectively evaluated among 63 living donors by paired-sample student's t-test and Lin's concordance correlation coefficient.

RESULTS

A new formula was developed SLV (mL) = 949.7 x BSA (m(2)) - 48.3 x age - 247.4 where age was counted as 1 for those <40, 2 if 41-60, and 3 if >60 years old. The calculated LV using our formula showed no significant difference from the actual LV using the paired-samples student's t-test (P = .653). Lin's concordance correlation coefficient showed substantial agreement between estimated LV using our formula and actual LV. Furthermore, this study also observed an almost perfect agreement between our formula and the Yoshizumi et al formula.

CONCLUSION

Our formula, which accurately estimated LV among Chinese adults, may be applicable to adults of other ethnicitis.

RNA interference-mediated silencing of the polo-like kinase 1 gene enhances chemosensitivity to gemcitabine in pancreatic adenocarcinoma cells

Gemcitabine is the first-line chemotherapeutic agent for advanced adenocarcinoma of the pancreas; however, chemoresistance to gemcitabine remains a major cause of failure for the clinical treatment of this disease. Polo-like kinase 1 (Plk-1) is highly expressed in pancreatic cancer cell lines and pancreatic tumour tissues, and is involved in a wide variety of cell cycle processes. Nevertheless, its biological role and implication for gemcitabine resistance are not clearly defined. In this study, we used RNA-interference (RNAi)-mediated depletion of Plk-1 to determine its potential for sensitizing pancreatic tumour cells to gemcitabine. We showed that the level of Plk-1 protein was correlated significantly with gemcitabine resistance in human pancreatic adenocarcinoma cells and that overexpression of Plk-1 reduced sensitivity to gemcitabine in these cells. In addition, small interfering RNA (siRNA)-mediated knockdown of Plk-1 caused cell cycle arrest at G2/M and the reduction of cellular proliferation. More importantly, the treatment of pancreatic cancer cells with Plk-1 siRNA followed by exposure to gemcitabine dramatically decreased cell viability and increased cellular apoptosis, as compared with treatment with either agent alone. These observations indicate that down-regulation of Plk-1 expression by RNAi enhances gemcitabine sensitivity and increases gemcitabine cytotoxicity in pancreatic tumour cells. This is the first demonstration that the combination of Plk-1 gene therapy and gemcitabine chemotherapy has synergistic anti-tumour activity against pancreatic carcinoma in vitro. This combination treatment warrants further investigation as an effective therapeutic regimen for patients with resistant pancreatic cancer and other tumours.

[Dynamic monitoring of arterial blood lactic acid in the prognosis of heart operation]

OBJECTIVE

To determine the clinical value of arterial blood lactic acid monitoring in patients after cardiac surgery.

METHODS

Relationship between dynamic blood lactic acid level and the prognosis of 200 patients (9 patients in the dead group, and 191 patients in the healing group) was analyzed after cardiac operation.

RESULTS

The level of blood lactic acid was (1.2+/-0.3) mmol/L in the healing group,and (5.6+/-0.9) mmol/L in the death group. The level of blood lactic acid in the healing group descended to normal in 24 hours, while that in the death group rose persistently. The dynamic change of lactic acid indicated more sensitively the prognosis of the disease than pH and BE.

CONCLUSION

The higher the arterial blood level of lactic acid, the longer the duration, the more critical the condition, the higher the mortality rate. Blood lactic acid level can be used as an excellent prognosis index for patients after cardiac surgery.

Ion source and low energy injection line for a central region model cyclotron

At CIAE, a 100 MeV H(-) cyclotron (CYCIAE-100) is under design and construction. A central region model (CRM) cyclotron was built for various experimental verifications for the CYCIAE-100 project and for research and development of high current injection to accelerate milliampere H(-) beam. The H(-) multicusp source built in 2003 has been improved recently to make the source operation more stable. A new injection line for axial low energy high current injection has been designed and constructed for the CRM cyclotron.

Off-line ion source terminal for ISAC at TRIUMF

The off-line ion source (OLIS) terminal consists of a microwave cusp ion source, either a surface ion source or a hybrid surface-arc discharge ion source and an electrostatic switch that allows selecting any one of the sources without mechanical intervention. These sources provide variety of beams to ISAC experiments, for commissioning the accelerators, for setting up the radioactive experiments, and for tuning the beam lines. The microwave ion source has been operational since 1995 and provides singly and doubly charged beams from various stable isotopes for many ISAC experiments at high and low energy areas. Originally its prime goal was to provide beams from gaseous elements, but later two ovens and a sputtering system were added in order to provide beams from liquids and from solids. The surface ion source installed in 2002 can provide low energy spread beams from alkali and semialkali elements. It also has three separate ovens and an ionizer. Therefore, it can provide three different temperature regions simultaneously to provide different beams to ISAC. It is mainly used for laser spectroscopy experiments and other experiments, which require a finite beam quality. A hybrid surface-arc discharge ion source was also developed and installed in order to meet specific demands from experiments. This source terminal is now automated for start up and for mass selection. It is capable of providing stable beams for months without maintenance and it is also capable of providing negative ion beams if required. To date, over 40 different isotopes including many rear isotopes were delivered to various experiments from the OLIS source terminal. Performances of the ion sources and some of the results are discussed.

Metal ion reduction and resultant deposition on viologen-functionalized LDPE films and viologen-containing microporous membranes

Photo-induced reduction of gold and platinum metal salt solutions was carried out using viologen graft copolymerized on low-density polyethylene (LDPE) films and viologen-containing poly(vinylidene fluoride) (PVDF-PVBV) microporous membranes. The effects of the UV irradiation time and concentration of the metal salt solutions on the metal ion reduction process and the resultant metal deposition on the polymeric substrates were investigated. The metal-polymer composites were characterized using X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and UV-visible absorption spectroscopy. The amount of metal uptake, the state of the metal, and the size of the metal particles were found to be strongly dependent on the UV irradiation time and the type and concentration of the metal salt solution. The microporous structure and the high viologen content of the PVDF-PVBV membrane constitute an effective matrix for metal ion reduction and preparation of metal nanoparticles.

The effect of electro-acupuncture on motor function recovery in patients with acute cerebral infarction: a randomly controlled trial

The aim of this study is to investigate the effect of electro-acupuncture treatment in acute phase of cerebral infarction on the motor functions. In this randomly controlled trial, 86 patients were allocated to two groups, the experimental group given clinical and electro-acupuncture treatments for a period of 4 weeks, and the control group given clinical treatment plus active and/or passive functional exercise. The result showed that the level of impairment and disability in both groups were improvement according to the Chinese Stroke Scale, Brunnstrom-Fugl-Meyer score, and Barthel Index throughout the study and 3 months after. The motor functions and the activities of daily living (ADL) were improved significantly in the electro-acupuncture group as compared with the control group (P < 0.05). Also, the results showed greater reduction of neurological deficit in the electro-acupuncture group than in the control group.

CONCLUSION

Early acupuncture treatment for acute stroke patients may improve motor functions, and consequently the activities of daily living.

Pulsed tissue Doppler imaging to assess myocardial viability by quantification of regional myocardial functional reserve

Dobutamine stress echocardiography (DSE) is used widely to evaluate myocardial viability, but is limited by the subjective nature of test interpretation. Assessment of systolic function by pulsed tissue Doppler imaging (TDI) during dobutamine stimulation may allow a more objective evaluation of myocardial functional reserve and, thus, myocardial viability. In 30 patients (58 +/- 9 years) with prior myocardial infarction, pulsed TDI with low dose dobutamine stress (10 microg/kg/min) was performed to assess myocardial viability. Qualitative assessment of two-dimensional (2-D) DSE and positron emission tomography (PET) were used for comparison. Peak systolic myocardial velocity was measured for each left ventricular segment (16 segments) at baseline and low dose dobutamine stress using pulsed TDI. The absolute and relative increases of peak systolic velocity from rest to low dose dobutamine stress were calculated. Three hundred sixty-four segments with adequate pulsed TDI tracing were divided according to either 2-D DSE or PET findings into normal, viable (mismatch), and nonviable (match) segments. The increase of peak systolic myocardial velocity from baseline to low dose dobutamine was significantly different between segments defined as normal, viable, and nonviable by 2-D DSE (2.71 +/- 1.91 cm/sec, 1.86 +/- 2.15 cm/sec, and 0.99 +/- 1.16 cm/sec, respectively; P < 0.001). The increase of peak systolic myocardial velocity from rest to low dose dobutamine for normal, mismatch, and match segments defined by PET was 2.72 +/- 1.96, 1.01 +/- 0.96 and 0.80 +/- 1.07 cm/sec, respectively (P < 0.001). In conclusion, the increase of peak systolic myocardial velocity during low dose dobutamine stimulation determined by pulsed TDI distinguishes between different myocardial viability states. It complements the standard interpretation of stress echocardiograms.

IFN-gamma-dependent and -independent initiation of switch recombination by NK cells

We have examined the effect of IL-2-propagated NK or NK-T cells on each of the steps required for B cell switch recombination leading to IgG2a production. The results indicate that NK cells, on their own and in the absence of IFN-gamma, can induce germline transcription in resting, IgG(-) B lymphocytes from the gamma2a locus as well as mRNA for activation-induced cytidine deaminase (AID) via a process that requires cell-cell interactions. The results also show that, in contrast to induction by T cells, activation by NK cells does not involve CD40-CD40 ligand interactions and does not extend to the induction of Igamma1 transcription. Furthermore, in contrast to stimulation by LPS and IFN-gamma or by T cells, the activation events initiated by NK cells do not result in significant synthesis of functional gamma2a mRNA in resting B lymphocytes even in the presence of IFN-gamma. Thus, induction of germline and AID transcripts are necessary but not sufficient events for functional switching to IgG2a. These experiments, showing that NK cells themselves cannot induce IgG2a production but can polyclonally program B lymphocytes so that they preferentially switch to this isotype may explain how activated NK cells can skew the Ag-specific immune response toward IgG2a. The findings also provide further demonstration of the definitive yet limited extent of how a non-Ag-specific component of the innate system can modulate the direction of the adaptive immune response.

Inappropriate expression of IgD from a transgene inhibits the function of antigen-specific memory B cells

IgD expression has been shown to be downmodulated upon mitogenic or antigenic activation of B cells. To investigate whether this decrease is of functional significance we studied a mouse strain that expresses transgenic IgD on all B cells. The rearranged gene encoding the heavy chain of this IgD requires endogenous gene rearrangement before it can be expressed; therefore, normal B cell development is not affected. As a result, both transgenic IgD and endogenous IgM and IgD are expressed on all peripheral B cells. We show that the presence of extraneous IgD does not affect normal B cell activation by polyclonal stimulators, nor does it affect the primary IgM or IgG responses to TI or TD antigens. However, the secondary memory response is significantly diminished. The decrease is not attributable to a defective generation of memory B cells; instead the activation of memory cells appears to be compromised. Since the depressed response can be overcome by prior aggregation of the transgenic IgD with allotype-specific anti-IgD antibodies, it appears that persistence of the transgenic IgD on memory cells may influence their ability to be activated. Thus, the decrease in IgD expression on normal B cells after activation may be necessary for optimal activation of memory cells.

Uptake and distribution of rare earth elements in rice seeds cultured in fertilizer solution of rare earth elements

The uptake behavior of rare earth elements (REEs) under pot conditions using deionized water and a REE fertilizer solution as the culture media as well as the distribution of REEs in rice proteins were studied. The uptake of REEs in rice seeds increased dramatically after a lag period of approximately three days. Roots can accumulate a much higher content of REEs than germs and the resting seeds. The REE content in each water-soluble (albumin) and salt-soluble (globulin) component of the rice seeds accounted for 5-8% and 4-6% of the total REEs, respectively. However, there are less than 1.5% of the total REEs were found in the alcohol-soluble (prolamin) and acetic acid-soluble (glutelin) components. The high performance liquid chromatography (HPLC) in the gel permeation and the reserved-phase were used to monitor changes in the molecular weight distribution changes of the soluble proteins of rice seeds during germination after having been cultured in the same solution for seven days. No changes occurred in the prolamin, while a slight change occurred in the albumin, globulin and glutelin. Fractionation of the albumin of rice seeds cultured in a REE fertilizer solution on the Sephadex G-100 column indicated that REEs, especially Ce, La, Pr and Nd, were associated mainly with biological compounds of a molecular weight between 10,000 and 12,000.

Sulfoglycolipid from the marine brown alga Sargassum hemiphylum

One kinds of glycolipid (SBI) have been isolated from the marine brown alga Sargassum hemiphyllum (Turn.) Ag. The structures of SBI have been determined as the sodium salt of 1-0-acyl-3-0-(6'-sulfo-alpha-D-quinovopyrannosyl) glycerol (acyl: tetradecanoyl, pentadecanoyl, 11-hexadecenoyl, hexadecanoyl, 10,13-octadecadienoyl, 9-octade cenoyl, 15-metylheptadecanoyl and 11-eicosenoyl 17: 1.5: 19: 153: 1: 19: 1: 2) on the basis of chemical and spectral evidence and GC-MS analysis, respectively. Four constituents of the SBI were new compounds [the sodium salt of 1-0-(11"-hexadecenoyl)-3-0-(6'-sulfo-alpha-D-quinovopyrannosyl) glycerol, the sodium salt of 1-0-(10",13"-octadecadienoyl)-3-0-(6'-sulfo-alpha-D-quinovopyrannosyl) glycerol, and the sodium salt of 1-0-(15"-metylhexadecenoyl)-3-0-(6'-sulfo-alpha-D-quinovopyrannosyl) glycerol, and the sodium salt of 1-0-(11"-eicosenoyl)-3-0-(6'-sulfo-alpha-D-quinovopyrannosyl) glycerol]. All compounds were isolated from marine brown alga for the first time.

Health effects of occupational exposures to vehicle emissions in Shanghai

The authors investigated the health effects of occupational exposures to vehicle emissions in 745 bus drivers, conductors, and taxi drivers, compared with 532 unexposed controls, in Shanghai. Logistic regression and general linear models were used to examine the relationship between exposure and respiratory illness. Results showed that the prevalences of some respiratory symptoms and chronic respiratory diseases were significantly higher (p < 0.05) in the exposed group than in the controls. The adjusted odds ratios for throat pain, phlegm, chronic rhinitis, and chronic pharyngitis were 1.95 (95% CI 1.55-2.46), 3.90 (95% CI 2.61-5.81), 1.96 (95% CI 1.11-3.46), and 4.19 (95% CI 2.49-7.06), respectively. Also, there were exposure time response relationships for the prevalences of phlegm and chronic respiratory disease. Pulmonary function and blood lead levels were not significantly correlated with exposure status. The results suggest that occupational exposure to vehicle emissions may induce detectable adverse health effects.

Status of persistent organic pollutants in the sediment from several estuaries in China

Sediment samples from three estuaries on the east coast of China were analyzed for persistent organic pollutants. Total PCB, PAH, and DDT concentrations in the sediments from Minjiang, Jiulongjiang, and Zhujiang estuaries ranged from 2 to 14 ng/g, 400 to 1500 ng/g, and 6 to 73 ng/g, respectively, in the sediments from these estuaries. The sources of PAH contamination were inferred from PAH compositions, with pyrogenic PAHs being the dominant source for Minjiang Estuary and petroleum related PAHs being the primary contributors to Jiulongjiang and Zhujiang estuaries. The high concentrations of DDT in the sediments from these estuaries were likely the result of widespread use of DDT in China in the 1960s and 1970s. Butyltin compounds were detected in the sediment from Jiulongjiang Estuary and Victoria Harbor, Hong Kong. Presence of butyltin compounds probably result from the shipping activities in these estuaries. Butyltin compounds were not detected in the sediments from Minjiang and Zhujiang estuaries. Contaminant concentrations were generally below levels expected to affect benthic organisms with the exception of DDTs.

[A clinical analysis of combination treatment with brachytherapy and external radiation, plus chemotherapy for the treatment of esophageal cancer]

OBJECTIVE

To analyse the value of various combinations of treatment for esophageal cancer.

METHODS

One hundred twenty cases of esophageal cancer were randomly divided into four groups, 30 cases in each group. Group I was treated with external radiation (RT) alone; group II, with RT plus brachytherapy; group III with RT plus chemotherapy, and group IV with RT plus brachytherapy and chemotherapy. RT with 60Co was given 2 Gy daily, 5 times a week, with a total dose of 60-74 Gy. Brachytherapy was given 6-8 Gy once weekly with a total dose of 18-24 Gy. Chemotherapy with carboplatin was given 100 mg/day, five days a week at first and fifth week.

RESULTS

The 1, 2, 3-year survival rate in group II, III and IV was higher than that in group I (P < 0.05). The 3-year survival rate of group I-IV patients was 13.3%, 36.7%, 40.0%, 46.7%, respectively. More patients died of cancer recurrence and progression in group I than in any of the other 3 groups of patients (P < 0.05). However, the frequency of distant metastasis was not significantly different.

CONCLUSION

The combination treatment with external radiation, brachytherapy and chemotherapy can improve the local control of tumor growth and the survival rate in esophageal cancer patients.

The functional relevance of NK-cell-mediated upregulation of antigen-specific IgG2a responses

We have previously shown that activation of NK cells by poly(I:C) or tumor treatment of mice increases the level of antigen-specific IgG2a (1, 2). We have now assessed the functional relevance of this effect of the innate immune system on the specific immune response. We found that the increased IgG2a significantly augments antibody-dependent cellular cytotoxicity mediated by NK cells both in vivo and in vitro. Furthermore, we show that both IgG3 producing plasma cells induced by T-independent antigens and IgG2a plasma cells induced in the presence of activated NK cells may be just as long-lived as plasma cells induced by T-dependent antigens. These results indicate that if NK cells are activated early in the immune response, before T cells are recruited, they could exert long-lasting effects.