Study of the Effect of Micro-Environment Stresses on Breast Tumor Initiating Cells by In Vitro Cell Tracking

Increasing clinical as well as experimental evidence supports the existence of a small population of tumor initiating cells (TIC) that possesses enhanced self-renewal capacity, and the ability to form tumors upon transplantation. These TIC, which highly resemble normal stem cells, are believed to be responsible for tumor initiation and propagation. Evidence also suggests that TIC reside in unique micro-environment which may account for their resistance to traditional chemo- and radiotherapy. Understanding the effect of micro-environment on TIC will have dramatic implications for breast cancer prevention, treatment, and drug development.It is known that tumor micro-environment is characterized by various degrees of chemical imbalance, including oxygen depletion (hypoxia), lactic acidosis, glucose deprivation and high oxidative stresses caused by elevated reactive oxygen species (ROS) [1]. These physiological stresses have significant clinical impact and are often related to poor patient prognosis [2]. Interestingly, recent studies revealed that there are molecular connections between physiological stress regulated transcription factors and pathways known to control stem cell function [3], suggesting that the micro-environment stresses may either promote TIC cell transformation or proliferation [4]. However, despite these molecular level findings, direct evidence on the effect of physiological stresses on the proliferation and differentiation of TIC is still missing.We use in vitro live cell tracking to study the influence of micro-environment on TIC. Primary cultured cells are prepared from breast cancer surgery specimen. They are cultured in suspension in serum free medium as mammospheres which have been demonstrated to be highly enriched with TIC [5]. Various physiological stresses are mimicked by growing cells in tissue culture incubators with 2% O2 (hypoxia), acidic medium (pH 6.7) with 25mM lactic acid, glucose deprivation condition by using glucose free DMEM medium, high ROS condition with 100uM H2O2. Cells are also infected with lentivirus to express H2B-GFP to label the cell nuclei so that they can be tracked by fluorescence imaging. Experiments are carried out in a full environmental controlled (CO2, O2, temperature, humidity) chamber and monitored by confocal imaging over prolonged time up to 96 hours. Since mammosphere cells grow in 3D instead of monolayer, they were scanned by confocal to reconstruct the 3D structure. We also developed computer programs for 3D segmentation to separate each cell, so that each cell within the mammosphere can be labeled and monitored individually. Such system allows us to draw a lineage tree for all the cells in the final mammosphere and detect the active dividing cells (which represent the differentiated cells) and the cells which reenter the quiescent status (which represent the progenitor cells), and hence allow us to study the effect of various micro-environment stresses on them.1. Vaupel, P., Semin Radiat Oncol, 2004. 14(3): p. 198-206.2. Schwickert, G., et al., Cancer Res, 1995. 55(21): p. 4757-9.3. Keith, B. and M.C. Simon, Cell, 2007. 129(3): p. 465-72.4. Li, Z., et al., Cancer Cell, 2009. 15(6): p. 501-13.5. Ponti, D., et al., Cancer Res, 2005. 65(13): p. 5506-11.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1163.

Early-life lead exposure affects the activity of TNF-alpha and expression of SNARE complex in hippocampus of mouse pups

This study aims to investigate the effects of maternal lead exposure on learning and memory ability and the protein expression of TNF-alpha and SNARE complex (SNAP-25, VAMP-2, and Syntaxin 1A) in hippocampus of mice offspring. Pb exposure was initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at 0.1%, 0.5%, and 1% groups, respectively. On the PND21, the learning and memory ability of mouse pups was tested by water maze test, and the Pb levels in their blood and hippocampus were also determined. The protein expression of TNF-alpha and SNARE complex in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than control group (P < 0.05). In the water maze test, the performances of 0.5% and 1% groups were worse than that of control group (P < 0.05). The expression of TNF-alpha, Syntaxin 1A, and VAMP-2 was increased in Pb-exposed groups comparing control group (P < 0.05), but the expression of SNAP-25 was decreased (P < 0.05). Up-regulation of TNF-alpha and disturbance of SNARE expression in the hippocampus of pups may contribute to impairment of learning and memory ability associated with maternal Pb exposure.

Functional recovery of callosal axons following demyelination: a critical window

Axonal dysfunction as a result of persistent demyelination has been increasingly appreciated as a cause of functional deficit in demyelinating diseases such as multiple sclerosis. Therefore, it is crucial to understand the ultimate causes of ongoing axonal dysfunction and find effective measures to prevent axon loss. Our findings related to functional deficit and functional recovery of axons from a demyelinating insult are important preliminary steps towards understanding this issue. Cuprizone diet for 3-6 wks triggered extensive corpus callosum (CC) demyelination, reduced axon conduction, and resulted in loss of axon structural integrity including nodes of Ranvier. Replacing cuprizone diet with normal diet led to regeneration of myelin, but did not fully reverse the conduction and structural deficits. A shorter 1.5 wk cuprizone diet also caused demyelination of the CC, with minimal loss of axon structure and nodal organization. Switching to normal diet led to remyelination and restored callosal axon conduction to normal levels. Our findings suggest the existence of a critical window of time for remyelination, beyond which demyelinated axons become damaged beyond the point of repair and permanent functional loss follows. Moreover, initiating remyelination early within the critical period, before prolonged demyelination-induced axon damage ensues, will improve functional axon recovery and inhibit disease progression.

High glucose attenuates insulin-induced VEGF expression in bovine retinal microvascular endothelial cells

PURPOSE

To investigate the effect of high glucose on insulin-induced vascular endothelial growth factor (VEGF) expression in bovine retinal microvascular endothelial cells (BRECs) and to probe into related mechanisms.

METHODS

BRECs were isolated as primary cultures and identified by immunostaining. Passage cells were initially exposed to normal (5 mM) or high glucose (30 mM) for 3 days, and equimolar L-glucose was supplemented for osmotic equation. BRECs were then treated with 100 nM insulin for 24 h or not, and cells were prepared for the determination of VEGF mRNA expression by real-time PCR. VEGF protein was determined by human umbilical vein endothelial cell proliferation assay, immunofluorescence, and ELISA. BRECs were treated with 5 or 30 mM glucose for 3 days and then cells cultured with 5 mM glucose were exposed to the PI3-K inhibitor wortmannin (100 nM), the P42/44 mitogen-activated protein kinase (MAPK) inhibitor U0126 (50 microM), or to the protein kinase C (PKC) inhibitor GF109203X (2 microM) 1 h before addition of 100 nM insulin. Twenty-four hours after incubation with insulin, the cells were subjected to real-time PCR and ELISA analyses.

RESULTS

Insulin or high glucose alone markedly increased VEGF mRNA and protein levels in BRECs (P<0.05, two-way ANOVA). However, the combination of insulin and high glucose displayed a weaker effect in promoting VEGF expression than did insulin alone (P<0.05, t-test). Pretreatment of cells with PI3-K inhibitor significantly (P<0.05, one-way ANOVA) suppressed the insulin-induced VEGF expression; neither pretreatment with the PKC inhibitor nor with the P42/p44 MAPK inhibitor showed an effect on the expression of VEGF at the mRNA or protein level (P>0.05, one-way ANOVA).

CONCLUSIONS

Both insulin and high glucose can markedly increase VEGF expression in BRECs at the mRNA and protein level. We propose that insulin may upregulate VEGF expression through the PI3-K signalling pathway in BRECs, and high glucose may attenuate insulin-induced VEGF expression by impairing PI3-K signalling pathways.

Radiosensitivity of canine osteosarcoma cells transfected with wild-type p53 in vitro

The p53 gene is one of the important tumour suppressor genes that are involved with the cell survival signal pathway. One of the major functions of the p53 protein is to organize cell cycle regulation and induction of apoptosis for cellular genetic stability. It has been documented that more than 50% of all human cancers include a p53 mutation. We evaluated the difference in radiosensitivity between upregulating the expression of canine wild-type p53 (cp53) in cultured osteosarcoma (D17) cells and naive D17 cells in vitro. We found that upregulating transfected cp53 D17 cells increased their radiation sensitivity in vitro, and there was a significant decrease (P < 0.009) in survival between cp53-transfected D17 cells and naive D17 cells. In this experiment, a p53 enhancement ratio (p53ER) reached approximately 3.0 at high doses. The transfected cp53 D17 cells were significantly more radiosensitive at all doses evaluated than naive D17 cells, except at 1 Gy where too few data points were available. The p53ER increased rapidly at doses less than 4 Gy, achieving a maximum of about 3.0 for doses of 4 Gy and above. This study shows the enhanced radiosensitivity of the transfected p53 at clinically relevant doses.

Polychlorinated biphenyls residues in the soil in Linfen, China

A total of 10 surface soil samples covering the whole territory of Linfen city were collected for analysis the 144 polychlorinated biphenyls (PCBs). The total PCBs concentration ranged from 0.2 to 3.4 ng g(-1) in urban soil and 0.5 to 14.8 ng g(-1) in industrial plant soil. Furthermore, increasing PCBs contamination was observed in northeast Linfen because of the distribution of industrial plants. Principal component analysis (PCA) revealed that the major source of PCBs in Linfen may be potentially associated with commercial #1 PCB through the long-range transmission. In total, PCBs were not a severe contamination in Linfen from current results.

Auto-regulation of estrogen receptor subtypes and gene expression profiling of 17beta-estradiol action in the neuroendocrine axis of male goldfish

Auto-regulation of the three goldfish estrogen receptor (ER) subtypes was examined simultaneously in multiple tissues, in relation to mRNA levels of liver vitellogenin (VTG) and brain transcripts. Male goldfish were implanted with a silastic implant containing either no steroid or 17beta-estradiol (E2) (100 microg/g body mass) for one and seven days. Liver transcript levels of ERalpha were the most highly up-regulated of the ERs, and a parallel induction of liver VTG was observed. In the testes (7d) and telencephalon (7d), E2 induced ERalpha. In the liver (1d) and hypothalamus (7d) ERbeta1 was down-regulated, while ERbeta2 remained unchanged under all conditions. Although aromatase B levels increased in the brain, the majority of candidate genes identified by microarray in the hypothalamus (1d) decreased. These results demonstrate that ER subtypes are differentially regulated by E2, and several brain transcripts decrease upon short-term elevation of circulating E2 levels.

The effects of a 3-year obesity intervention in schoolchildren in Beijing

BACKGROUND

Childhood obesity has become a health problem in urban areas in China. Intervention to reduce childhood obesity should be of high priority. School-based intervention programmes are needed to deal with the growing prevalence of childhood obesity in China.

METHODS

Five primary schools were selected randomly for this study in the Beijing urban area in China; two were allocated to the intervention group and three to the control group. A total of 2425 children (1029 children in intervention schools and 1396 children in control schools) took part in the study for 3 years. In the intervention group, children and their parents were involved in a programme of nutrition education and physical activity. Control school students followed their usual health and physical education curriculum with no extra intervention.

RESULTS

After the 3-year intervention, the prevalence of overweight and obesity were significantly lower in the intervention schools than in the control schools (overweight: 9.8% vs. 14.4%, P < 0.01; obesity: 7.9% vs. 13.3%, P < 0.01). The prevalence of overweight and obesity decreased by 26.3% and 32.5% in intervention schools respectively after intervention. The prevalence of overweight and obesity increased in control schools. There was also significant difference in body mass index between intervention and control schools (18.2 +/- 2.6 vs. 20.3 +/- 3.4, P < 0.01) after intervention. More non-obese children became obese in the control schools (7.0%) than in the intervention schools (2.4%) at end line (P < 0.01). Among the children who were obese at baseline, 49.2% remained obese at end line in intervention schools while 61.9% remained obese in control schools (P < 0.01).

CONCLUSIONS

Our study showed that an intervention programme could be feasible in schools in Beijing, China. The prevalence of overweight and obesity was reduced in schoolchildren in Beijing through an intervention focused on nutrition education and physical activity. Overweight and obesity children as well as normal weight children and their parents should be involved in such an intervention programme.

Behavioral and biochemical studies of total furocoumarins from seeds of Psoralea corylifolia in the chronic mild stress model of depression in mice

Depression is related to alterations of the monoamine oxidase (MAO), hypothalamic-pituitary-adrenal (HPA) axis, and oxidative systems, and some antidepressants achieve their therapeutic effects through alteration of following biochemical markers of depression: MAO-A and MAO-B activities, cortisol levels, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels. The seeds of Psoralea corylifolia, otherwise known as Buguzhi, have long been used for treatments of various symptoms associated with aging in China. Furocoumarins are the most widespread secondary metabolites in this species. The present study was designed to evaluate the potential antidepressant-like activity of total furocoumarins of P. corylifolia (TFPC) in the chronic mild stress (CMS) model of depression. Mice subjected to CMS exhibited a reduction in sucrose intake. Conversely, brain MAO-A and MAO-B activities, plasma cortisol levels, and liver SOD activity and MDA levels were increased following CMS exposures. The time-course for reversal of CMS-induced deficits in sucrose consumption by TFPC was dose-dependent. Thus, the statistically significant effect of the higher dose of TFPC (50 mg/kg body wt.) was observed after 3 days of treatment, while 6 days of treatment were required in the group receiving a lower dose (30 mg/kg body wt.) of TFPC. TFPC reversed these biochemical changes. These results suggest that TFPC may possess potent and rapid antidepressant properties that are mediated via MAO, the HPA axis and oxidative systems and these antidepressant actions could make TFPC a potentially valuable drug for the treatment of depression in the elderly.

Behavioral, neurochemical and neuroendocrine effects of the ethanolic extract from Curcuma longa L. in the mouse forced swimming test

Curcuma longa L. (turmeric) has been used for centuries in traditional Chinese medicine as a treatment for mental disorders including depression. The studies described here were undertaken to determine the behavioral, neurochemical and neuroendocrine effects of the ethanolic extract from Curcuma longa using the forced swimming test (FST) in male ICR strain of mice. The ethanolic extract was found to reduce the duration of immobility in the mouse FST when orally administered for 21 days. The extract markedly attenuated swim stress-induced decreases in serotonin, 5-hydroxyindoleacetic acid, noradrenaline and dopamine concentrations, as well as increases in serotonin turnover. Furthermore, the ethanolic extract of Curcuma longa significantly reversed the swim stress-induced increases in serum corticotropin-releasing factor and cortisol levels. Under these conditions, the ethanolic extract of Curcuma longa was partly different from fluoxetine and amitriptyline. These results suggested that antidepressant properties of the ethanolic extract of Curcuma longa was mediated through regulations of neurochemical and neuroendocrine systems and it may be a useful agent against depression.

Confirmation of four nitroimidazoles in porcine liver by liquid chromatography–tandem mass spectrometry

A sensitive and reliable multiresidue method is described for analysis of ronidazole, metronidazole, dimetridazole and the common metabolite of ronidazole and dimetridazole, 2-hydroxymethyl-1-methyl-5-nitroimidazole in swine liver. The sample preparation procedure was based on liquid-liquid extraction and mixed mode cation exchange/reverse phase solid-phase extraction. The compounds of interest were determined by reverse phase gradient liquid chromatography separation and tandem mass spectrometry (MS/MS) in the multiple reaction monitoring (MRM) mode. The limits of confirmation were 0.1-0.5 microg kg(-1) for the analytes.

Ultrasonic treatment stimulates multiple shoot regeneration and explant enlargement in recalcitrant squash cotyledon explants in vitro

Ultrasonic treatment (0.5-2 min) stimulated multiple shoot regeneration to high levels in vitro from recalcitrant cotyledon explants of commercial squash (Cucurbita pepo L.) cultivars Ma'yan and Bareqet, on Murashige and Skoog [Physiol Plant 15:473-497, 1962] (regeneration) medium augmented with 4.4 microM benzyladenine. At this stage, unsonicated control explants regenerated only a few very small shoots or bud-like structures. Ultrasound also stimulated massive explant growth. Ultrasound treatment resulted in further multiple shoot production (five times greater than control) after explant transfer to elongation medium (Murashige and Skoog [Physiol Plant 15:473-497, 1962] medium with 0.44 microM benzyladenine and 2.9 microM gibberellic acid). Longer ultrasonic treatments (5 or 10 min) promoted multiple shoot regeneration and explant growth accompanied by hyperhydration. Scanning electron microscope observations showed that 2 min ultrasound changed the joint area between epidermal cells and removed some of the surface from the cotyledon epidermal cells, without gross surface injury to the explants. Longer periods of ultrasound (5-10 min) caused further surface erosion. Rubbing the explant contact surface with chloroform or sandpaper emulated the effect of sonication on shoot regeneration and explant growth, demonstrating that ultrasound exerts its morphogenic influence by surface removal. Sonication of explants from other batches of squash seeds (of cultivars Ma'yan and True French), that regenerated without such treatment, reduced regeneration and caused hyperhydration. This is the first report of stimulation of in vitro regeneration by ultrasound treatment.

Crystallization and preliminary X-ray diffraction analysis of E. coli arginyl-tRNA synthetase in complex form with a tRNAArg

Amino acids are building blocks of proteins, while aminoacyl-tRNA synthetases (aaRSs) catalyze the first reaction in such building: the biosynthesis of proteins. The E. coli arginyl-tRNA synthetase (ArgRS) has been crystallized in complex form with tRNA(Arg) (B. stearothermophilus), at pH 5.6 using ammonium sulfate as a precipitating agent. Two crystal forms have been identified based on unit cell dimension. The complete data sets from both crystal forms have been collected with a primitive hexagonal space group. A data set of Form II crystals at 3.2 A and 94% completeness has been obtained, with unit cell parameters a = b = 98.0 A, c = 463.2 A, and alpha = beta = 90 degrees , gamma = 120 degrees , being different from a = b = 110.8 A, c = 377.8 A for form I. The structure determination will demonstrate the interaction of these two macromolecules to understand the special mechanism of ArgRS that requires the presence of tRNA for amino acid activation. Such complex structure also provides a wide opening for inhibitor search using bioinformatics.

Expression of GCIP in transgenic mice decreases susceptibility to chemical hepatocarcinogenesis

Transcription factors with helix-loop-helix (HLH) motif play critical roles in controlling the expression of genes involved in lineage commitment, cell fate determination, proliferation, and tumorigenesis. To examine whether the newly identified HLH protein GCIP/CCNDBP1 modulates cell fate determination and plays a role in hepatocyte growth, proliferation, and hepatocarcinogenesis, we generated transgenic mice with human GCIP gene driven by a liver-specific albumin promoter. We demonstrated that in GCIP transgenic mice, the overall liver growth and regeneration occurred normally after liver injury induced by carbon tetrachloride (CCl4). In the diethylnitrosamine (DEN)-induced mouse hepatocarcinogenesis, we demonstrated that overexpression of GCIP in mouse liver suppressed DEN-induced hepatocarcinogenesis at an early stage of tumor development. The number of hepatic adenomas at 24 weeks was significantly lower or not detected in GCIP transgenic male mice compared to the control mice under the same treatment. Although GCIP has little inhibition on the number of hepatic tumors at later stages (40 weeks), hepatocellular tumors in GCIP transgenic mice are smaller and well-differentiated compared to the poorly differentiated tumors in wild-type mice. Furthermore, we demonstrate that GCIP functions as a transcriptional suppressor, regulates the expression of cyclin D1, and inhibits anchorage-independent cell growth and colony formation in HepG2 cells, suggesting a significant role of GCIP in tumor initiation and development.

Microkinetic modeling of CO TPD spectra using coverage dependent microcalorimetric heats of adsorption

CO adsorption on the ternary methanol synthesis Cu/ZnO/Al2O3 catalyst was studied in detail by means of adsorption microcalorimetry and flow temperature-programmed desorption (TPD). Based on these experimental data, we established a microkinetic analysis method, which provides information about the adsorption kinetics of CO on the catalyst surface. Experimentally derived microcalorimetric heats of adsorption were applied in a microkinetic model to simulate TPD curves with varying initial coverage. Two approaches were used: an integral approach based on evaluation of the integral heats of adsorption which predicts the experimental TPD curves roughly and provides first approximations for the preexponential factors. The second, more detailed approach was based on the simulation of the adsorption isotherm taking the experimentally determined coverage-dependence of the heat of adsorption into account. This approach led to a significantly improved agreement between experimental and simulated TPD curves. Moreover, it was possible to derive the standard entropy of adsorption. The general applicability of our approaches is demonstrated by analyzing the CO TPD and microcalorimetry data obtained with a binary ZnO-free Cu/Al2O3 catalyst.

The influence of strongly reducing conditions on strong metal–support interactions in Cu/ZnO catalysts used for methanol synthesis

A systematic series of binary and ternary copper catalysts was investigated using the methanol synthesis reaction at atmospheric pressure. Strong metal-support interactions between copper and zinc oxide induced by strongly reducing conditions were probed by the adsorption of carbon monoxide, which was monitored qualitatively and quantitatively by a combination of microcalorimetry, temperature-programmed desorption experiments and Fourier transform infrared spectroscopy. For the zinc oxide-containing catalysts, the pretreatment in flowing carbon monoxide at 493 K resulted in a severe decoration of the copper metal particles with ZnOx adspecies, whereas after methanol synthesis at 493 K the state of the copper was essentially identical to that seen after hydrogen reduction. Copper was always found to be present in its zero-valent state.

Electrocardiographic method for identifying drug-induced repolarization abnormalities associated with a reduction of the rapidly activating delayed rectifier potassium current

Several important non-cardiac drugs have been removed from the market after revealing harmful effect that was not identified during prior safety-assessment studies. We developed a new technique for the measurements of repolarization abnormalities from surface ECGs; this method improves sensitivity and specificity of the current technique used to identify the presence of abnormal ion current kinetics in the myocardial cells namely a prolongation of the QT interval on the surface ECG signal. We described in this paper the method and preliminary results, revealing the superiority of our technique that may play a role in the future of drug-safety assessment.

Dynamic HIV/AIDS Parameter Estimation With Application to a Vaccine Readiness Study in Southern Africa

This paper proposes a procedure of parameter estimation for all parameters of the three-dimensional HIV model. The least square based procedure uses standard optimization routines to allow parameter extraction for individual patients. It is shown how additional information from outside a measurement dataset can be included in the estimation routine to increase the reliability and accuracy of parameter estimates. A dataset from 44 patients of Southern Africa is analyzed to find the set point and the time until set point for these patients together with an estimate of the model parameters with confidence intervals for the cohort. The procedure is also applied to a long-term dataset of the HIV/AIDS progression to find possible variations in parameters.

Preferential expression of hPGFS in primary SCCHN and tumour cell lines derived from respiratory and digestive organs

Identifying overexpressed genes in tumours is a critical step for tumour diagnosis, prognosis, and treatment. Using differential display polymerase chain reaction, sequence analysis, and gene Blast searches, we discovered that human prostaglandin F synthase (hPGFS) was upregulated in squamous cell carcinoma of the head and neck (SCCHN). Northern blot analysis indicated that up to a 16-fold increase in the level of hPGFS expression was detected in 40.5% (15 out of 37) of SCCHN primary tumours. The increased expression of hPGFS in SCCHN was primarily detected in SCC of larynx and hypopharynx (59%, P<0.05). Using the same primary tissue samples, increased levels of epidermal growth factor receptor (EGFR) expression were detected in only 32% of tumour tissues, suggesting hPGFS may have the potential to become a drug target or molecular marker for SCCHN. To determine if the increased level of hPGFS expression came from tumour cells, we determined the level of hPGFS expression in SCCHN tumour cell lines. A high level of hPGFS expression was detected in four out of five tumour SCCHN cell lines. To determine if upregulation of hPGFS is SCCHN-specific, hPGFS expression was analysed in 59 tumour cell lines derived from different types of tumours. The expression of hPGFS was increased from two- to 500-fold in a large portion of cell lines derived from lung (five out of nine), colon (five out of seven) as well as head and neck cancer (four out of five). These data link hPGFS expression to tumours located in the respiratory and digestive organs.

Structure, evolution and expression of the FOXL2 transcription unit

FOXL2 is a putative transcription factor involved in ovarian development and function. Its mutations in humans are responsible for the blepharophimosis syndrome, characterized by eyelid malformations and premature ovarian failure (POF). Here we have performed a comparative sequence analysis of FOXL2 sequences of ten vertebrate species. We demonstrate that the entire open reading frame (ORF) is under purifying selection leading to strong protein conservation. We also review recent data on FOXL2 transcript and protein expression. FOXL2 has been shown 1) to be the earliest known sex dimorphic marker of ovarian determination/differentiation in vertebrates, 2) to have, at least in mammals, an ovarian expression persisting until adulthood. The conservation of its sequence and pattern of expression suggests that FOXL2 might be a key factor in the early development of the vertebrate female gonad and involved later in adult ovarian function. Finally, we provide arguments for the existence of an alternative transcript in rodents, that may arise from a differential polyadenylation. Although it has only been demonstrated in rodents, its presence/absence in other species deserves further investigation.

Shoot production in squash (Cucurbita pepo) by in vitro organogenesis

Seedling-derived cotyledon explants of squash ( Cucurbita pepo L.) of commercial cultivars True French, Ma'yan and Goldy were regenerated in vitro on Murashige and Skoog medium augmented with 1 mg/l benzyladenine. After 4 weeks in culture small shoots and buds regenerated only on the most proximal cotyledon edge. Culture on an elongation medium with a reduced cytokinin concentration (0.1 mg/l) with or without 1 mg/l gibberellic acid (GA(3)) facilitated the recovery of shoots. Fresh shoots could be recovered at each subculture of the regenerating mass. Peak productivity was during the third cycle of subculture, and shoot production ceased after the fifth subculture. Culture on elongation medium supplemented with GA(3) was 55% more effective with respect to overall shoot production than that on medium without GA(3), with 22 shoots recovered in total per explant from the former. Regeneration occurred under both light and dark conditions. All of the shoots tested were diploid. The shoots were rooted and transferred to the greenhouse where they grew and flowered normally.

A Negative Element Located in the Upstream Flanking Region of the Gene Encoding Arginyl-tRNA Synthetase (argS) from Escherichia coli

The gene, argS, encoding the arginyl-tRNA synthetase (ArgRS) from Escherichia coli ( E.coli ) was overexpressed 1 000 fold in the transformant when E. coli TG1 was transformed with the recombinant plasmid containing argS and pUC18. In order to investigate the regulation of expression of E. coli argS, a series of deletion mutations was constructed. The results of SDS-PAGE showed that deletions of the whole 5' flanking region (argSdelta1) or the region in front of Shine-Dalgarno Sequence (argSdelta2) or the -10 region of promoter (argSdelta3), caused no overexpression of argS. If argS was deleted from 3' end of the flanking region (-189 nt) to the upstream of -10 region of promoter (argSdelta4), the -35 region (argSdelta5), -52 nt (argSdelta6), -70 nt (argSdelta7) and -122 nt (argSdelta8), respectively, the mutant gene was overexpressed to a level similar to that of argS bringing the full length 5' flanking region. However, in the expression of argSdelta4, argSdelta5, argSdelta6, some of ArgRS formed an inclusion body. By determination of RNA dot hybridization, the amount of mRNA produced in the transcription of argSdelta4, argSdelta5 and argSdelta6 was about 2--3 times than that of the wild type argS, argS delta7 and argS delta8. This indicated that the deletion of a 19 nt sequence (AATAGTGAAAACGGCAATA) located between -52 nt and -70 nt of the gene increased the transcription of argS. The 19 nt sequence is a negative region that represses transcription of argS. Deletion of the negative element may result in a faster production of ArgRS and the accumulation of some unfolding protein intermediates aggregating to form the inclusion body. The result by analysis of gel retardation shows that a factor binds to the negative element. Arginine induced specifically the transcription of argS and its effect correlated with the above negative element.

Regression of tumors by IFN-alpha electroporation gene therapy and analysis of the responsible genes by cDNA array

The key to success with nonviral gene therapy as a treatment for cancer is to discover effective therapeutic genes and gene delivery methods and to understand how tumors are eradicated. We discovered that electroporation of IFN-alpha DNA into tumors in the SCCVII tumor-bearing mice led to tumor eradication in 50% of the mice and a more than two-fold increase in survival time when compared with controls (P = 0.0012). Analyses using cDNA array and Northern blot indicated that the genes responsible for the therapeutic effect of electro-IFN-alpha gene therapy included IRF-7, Granzyme A, Granzyme C, Gjb2, Krt14, Mig, IP-10 and MCP3. Because most of these genes have been known to either inhibit angiogenesis (Mig, IP-10), inhibit tumor growth (Gjb2, MCP3), kill tumor cells (Granzyme A and C), or induce expression of antitumor gene (IRF-7), they may become promising therapeutic gene candidates for a combination gene therapy approach to cancer treatment.

Nanocrystalline alpha-Ni(OH)2 prepared by ultrasonic precipitation

Nanocrystalline alpha-Ni(OH)2 was prepared by an ultrasonic precipitation/stirring method. Results of X-ray diffraction, transmission electron microscopy, infrared, and thermogravimetric measurements confirm that the sample obtained is alpha phase. Compared with the sample prepared without ultrasonic stirring, the crystal structure of the alpha phase sample has been changed from beta phase. The crystalline size of the sample is about 20 nm, which is smaller than the sample produced without ultrasonic stirring (70 nm).

Effects of the oral spirochete Treponema denticola on interleukin-8 expression from epithelial cells

This communication demonstrates that the interaction of the oral spirochete Treponema denticola 35405 with KB epithelial cells does not lead to the induction of interleukin-8 production as occurs with a variety of other bacteria. Utilizing the dentilisin protease mutant K1 of T. denticola, this property was demonstrated to be primarily a function of the expression of the protease by strain 35405.

Analysis of the expression pattern of Ebp1, an ErbB-3-binding protein

Ebp1, a member of the PA2G4 family, was isolated as an ErbB-3-binding protein in our laboratory using yeast two hybrid analysis. Although Ebp1 mRNA is ubiquitously expressed, little is known about either the expression of Ebp1 protein in vivo or its translation initiation site. Western blotting analysis of a wide range of cell lines and primary tissue indicated that in the majority of cases Ebp1 is expressed as a single protein which migrates at 48 kDa in SDS-polyacrylamide gels. We show using epitope-tagged expression constructs that the second, not the first, in-frame ATG is used for the initiation of translation of the endogenous protein, encoding a protein predicted to be 41.5 kDa. The molecular mass of endogenous Ebp1 protein derived from mouse liver and brain was determined by mass spectrometry and the data confirm that translation of endogenous Ebp1 in tissues is initiated from the second in-frame ATG.

Loss of presenilin 1 is associated with enhanced beta-catenin signaling and skin tumorigenesis

Presenilin 1 (PS1) is required for the proteolytic processing of Notch and the beta-amyloid precursor protein (APP), molecules that play pivotal roles in cell-fate determination during development and Alzheimer's disease pathogenesis, respectively. In addition, PS1 interacts with beta-catenin and promotes its turnover through independent mechanisms. Consistent with this activity, we report here that PS1 is important in controlling epidermal cell proliferation in vivo. PS1 knockout mice that are rescued through neuronal expression of human PS1 transgene develop spontaneous skin cancers. PS1-null keratinocytes exhibit higher cytosolic beta-catenin and beta-catenin/lymphoid enhancer factor-1/T cell factor (beta-catenin/LEF)-mediated signaling. This effect can be reversed by reintroducing wild-type PS1, but not a PS1 mutant active in Notch processing but defective in beta-catenin binding. Nuclear beta-catenin protein can be detected in tumors. Elevated beta-catenin/LEF signaling is correlated with activation of its downstream target cyclin D1 and accelerated entry from G(1) into S phase of the cell cycle. This report demonstrates a function of PS1 in adult tissues, and our analysis suggests that deregulation of beta-catenin pathway contributes to the skin tumor phenotype.

[Expression and drug resistance of human MGMT gene in hemopoietic cells mediated by bicistronic retroviral vector]

OBJECTIVE

To increase myeloid progenitors resistance to chemotherapy and prevent myelosuppression caused by alkylating agents.

METHODS

Total cellular RNA was extracted from human liver and cDNA was synthesized by superscript reverse transcriptase, a polymerase chain reaction(PCR) was conducted. We obtained a full length cDNA fragment encoding human alkyguarine-DNA-alhyltransferase(MGMT). The PCR product was cloned into pGEMT-T vector and further subcloned into G1Na retrovirus expression vector. Then the recombinant plasmid was transduced into the packaging cell lines GP+E86 and PA317 by lipofect AMINE.

RESULTS

By using the medium containing BCNU for cloning selection and ping-ponging supernatant infection between ecotropic produced clone and amphotropic producer clone, we obtained high titer amphotropic PA317 producer clone with the highest titer up to 8.6-10 CFU/ml. Human hematopoietic cells were infected repeatedly with this high titer virus under stimulation of hemopoietic growth factors IL-3, IL-6 and SCF. PCR, RT-PCR, Southern blot, Western blot and MTT analyses showed that MGMT gene has integrated into the genomic DNA of human hemopoietic cells and expressed efficiently.

CONCLUSIONS

This study provides a foundation for application of gene therapy to tumor clinical trial.

A study of factors related to the incidence of cataract in patients with non-insulin dependent diabetes mellitus

PURPOSE

To investigate the factors related to the development of cataract in patients with non-insulin dependent diabetes mellitus(NIDDM).

METHODS

792 NIDDM patients received ophthalmologic examinations including visual acuity, external status of the eyes, slit lamp microscopy and ophthalmoscopy. Glucose, urea nitrogen(BUN), creatinine(Cr), urine acid(UA), N-acetyl-beta 2-D-glucosaminidase (NAG), beta 2-microglobulin(beta 2-MG) and serum albumin in blood were quantitatively tested. Glucose, pH value, protein, cells, cast and ketobodies in urine were assayed. Diagnosis of cataract was based on lens opacities classification system II. Any patient meeting "NII", "CII" or "PII" level was diagnosed as cataract.

RESULTS

The incidence of cataract in this group of NIDDM was 62.37% (494/792), which significantly related to the duration of the disease course, but not to the sex of the patient. The occurrence rate of cataract in patients suffering from NIDDM of less than five years duration, from five to ten years, and more than ten years was 49.67% (228/459), 71.84% (125/174), and 88.68% (141/159), respectively. The occurrence of cataract in patients diagnosed of the disease from five to ten years and more than ten years was much higher than that of those with the course of the disease less than five years(P < 0.05 and P < 0.001, respectively). Rising concentrations of blood urea nitrogen, creatinine, glycosylated hemoglobin HbA1c(G-HbA1c), N-acetyl-beta 2-D-glucosaminidase(NAG) and beta 2-microglobulin(beta 2-MG) indicated malfunction of the kidneys, and the rate of cataract occurrence in these patients was higher.

CONCLUSION

This study indicates that prolongation of the duration of non-insulin dependent diabetes mellitus, renal dysfunction, as well as poor blood glucose control, may accelerate the development of cataract.

[Screening and characterization of human phage antibody to hepatitis C core antigen]

OBJECTIVE

To screen and characterize human phage antibody (ScFv) against hepatitis C core antigen.

METHODS

The recombinant phages were panned by core antigen that was coated in a microtiter plate. After three rounds of biopanning, 48 clones were determined specific to core antigen. The specificity of each ScFv colone was determined by ELISA. The coding gene for HCV protein ScFv has been sequenced.

RESULTS

Phage antibody for HCV core protein had a specific combination character with core antigen of hepatitis C virus. The DNA sequence data showed that the ScFv gene included 774 bp.

CONCLUSIONS

Human single chain antibody to hepatitis C core antigen has been identified by means of the phage display technology.

[Clinical observation on effect of baisuifang oral liquid in treating vascular dementia]

OBJECTIVE

To study the effect of Baisuifang Oral Liquid (BSF) in treating vascular dementia.

METHODS

Patients selected according to the diagnostic standard of American Association of Psychiatry were randomly divided into two groups, the 37 patients in the BSF treated group and the 28 patients in the control group treated by Naofukang with therapeutic course of 3 months. Changes of clinical symptoms, TCM Syndrome, mini-mental state examination (MMSE) and activity of daily living (ADL) score, hemorrheologic characters, platelet aggregation and blood lipid were observed.

RESULTS

BSF could ameliorate the symptoms and TCM Syndrome, decrease blood lipid, improve the hemorrheologic character, elevate the MMSE and ADL score of patients. The total effective rate in the treated group was 75.68% and the markedly effective rate 24.32%, which were obviously superior to those in the control group respectively.

CONCLUSION

BSF is an effective Chinese herbal preparation in treating vascular dementia, which could promote the restoration of learning memory, and improve the clinical symptoms.

DAMBE: software package for data analysis in molecular biology and evolution

DAMBE (data analysis in molecular biology and evolution) is an integrated software package for converting, manipulating, statistically and graphically describing, and analyzing molecular sequence data with a user-friendly Windows 95/98/2000/NT interface. DAMBE is free and can be downloaded from http://web.hku.hk/~xxia/software/software.htm. The current version is 4.0.36.

Epidemiological investigation of Histoplasma capsulatum infection in China

OBJECTIVE

To provide reliable information concerning the presence or the absence of Histoplasma capsulatum (H. capsulatum) infection in China, and data concerning this respect.

METHODS

Three hundred normal people and 435 hospitalized patients, who lived in Hunan and Jiangsu provinces, and the Xinjiang Autonomous Region, were tested with yeast-phase histoplasmin (ALK/Berkerley Biologicals Laboratories, USA) and human pure protein derivative of tuberculin (PPD) on the volar surface of the forearm. Any reaction to the antigens over 5.0 mm in diameter of induration at 48-72 hours was considered positive.

RESULTS

A total of 138 subjects (18.8%) in 735 patients reacted to histoplasmin with 5.0-45.0 (9.1 +/- 4.3) mm indurations. Significant differences of positive skin reaction rates in normal subjects were found in Hunan, Jiangsu and Xinjiang (8.9% vs 15.1% vs 2.1%). The overall positive rate of patients was 25.5%. Patients with tuberculosis [31.7% (78/246)] had a significantly higher positive skin reaction rate in comparison with those suffering from pneumonia [17.7% (11/62)], lung cancer [20.9% (9/43)], chronic obstructive pulmonary disease [17.3% (9/52)] and other diseases [12.5% (4/32)] (P < 0.01). Of 562 cases, 292 cases (52.0%) reacted to PPD with indurations of 5-50 (13.7 +/- 4.9) mm in diameter, 63 cases (11.2%) reacted to both histoplasmin and PPD, while 38 cases (6.9%) reacted to histoplasmin but not to PPD.

CONCLUSIONS

The data suggest that there is H. capsulatum herd infection in China. The infection rate in Southeast China is higher than that in the Northwest, and the infection rate of patients with pulmonary tuberculosis is higher than that of normal persons and other pneumonopathy patients.