Pharmacokinetics of a novel amoxicillin/colistin suspension after intramuscular administration in pigs

An amoxicillin (AMO) or colistin (COS) oil suspension was developed and corresponding pharmacokinetics studies were conducted in pigs after i.m. injection. The combination product is a white- to cream-colored oil suspension which is easy to be re-dispersed. Settling volume ratio, syringeability and flowability of the product is well consistent with the technical standards set by the Ministry of Agriculture of People's Republic of China. Two studies were conducted to investigate the pharmacokinetics of the combination product in swine. First, the pharmacokinetics of the combination product was compared with those of the same products merely removing either AMO or COS. No significant change in the major pharmacokinetic parameters (C(max) , T(max) , MRT, t(1/2λ) , AUC and AUMC) was observed when either component was removed from the combination product, indicating that AMO and COS do not interfere with each other in their absorption and distribution in the tissue when used as a combination. Second, the pharmacokinetics of the combination product was compared with that of their respective single products. It was found that the apparent elimination half-lives (t(1/2λ) ) of AMO and COS in combination product were 6.38 and 8.09 h, which were 2.40 and 2.38 times longer than the single products, respectively. Thus, the novel AMO/COS suspension extended significantly the half-life of both drugs to maintain a longer drug residence time in pigs when compared to their single products.

Advantage of carbonate-versus citrate-based alkalinization on bone metabolism in moderately exercising aged male rats fed an acidogenic diet

This study aims to determine the effects of different alkaline supplementations on high protein diet-induced abnormalities affecting bone metabolism in rats which were also undergoing physical exercise of moderate intensity. Sixty elderly Sprague-Dawley rats were randomly divided into four groups of 10 rats each and treated for 16 weeks as follows: baseline control group fed normal food (C); acidic high-protein diet supplemented group (chronic acidosis, CA group), bicarbonate-based alkaline formula (Basenpulver, Named, Italy) supplemented chronic acidosis (BB-CA) and citrate-based alkaline supplement (CB-CA). Throughout the supplementation period, rats were put on a treadmill training mimicking a moderate level of exercise. In the CA group, 24-hour urinary calcium (Ca) and phosphorus (P) excretion were increased over 30 percent (p<0.05 vs normal diet controls). However serum Ca was not significantly changed. Femural and tibial BMD and BMC was significantly decreased in the CA group (p<0.05) but both alkaline supplementations prevented such phenomenon (p<0.05 vs CA), without significant difference between the two formulations although the BB-CA group showed significantly more preserved trabecular bone volume (p<0.05 vs CB-CA group). An increased level of over 50 percent of urinary Dpd observed in the CA group (p<0.001) was reverted to normal by both supplementations (p<0.001 vs CA group). The same applied to urinary net acid excretion (p<001) with BB-supplementation performing better than CB-supplementation (p<0.05). Moreover, while the latter did not modify Nterminal telopeptide value, BB-supplementation significantly normalized this parameter (p<0.05 vs CA group) which exercise and acidic protein diet had modified (p<0.01 vs control diet). Overall, the present study shows that a bicarbonate-based alkaline formula, when administered to a dose amenable to clinical use, may significantly protect bone structure in exercising aged animals to a greater extent than a quali/quantitavely similar citrate-based formula.

Competitive electroporation formulation for cell therapy

Established cell transfection via nucleofection relies on nucleofection buffers with unknown and proprietary makeup due to trade secrecy, inhibiting the possibility of using this otherwise effective method for developing cell therapy. We devised a three-step method for discovering an optimal formulation for the nucleofection of any cell line. These steps include the selection of the best nucleofection program and known buffer type, selection of the best polymer for boosting the transfection efficiency of the best buffer and the comparison with the optimal buffer from an established commercial vendor (Amaxa). Using this three-step selection system, competitive nucleofection formulations were discovered for multiple cell lines, which are equal to or surpass the efficiency of the Amaxa nucleofector solution in a variety of cells and cell lines, including primary adipose stem cells, muscle cells, tumor cells and immune cells. Through the use of scanning electron microscopy, we have revealed morphological changes, which predispose for the ability of these buffers to assist in transferring plasmid DNA into the nuclear space. Our formulation may greatly reduce the cost of electroporation study in laboratory and boosts the potential of application of electroporation-based cell therapies in clinical trials.

Beneficial nutraceutical modulation of cerebral erythropoietin expression and oxidative stress: an experimental study

The main object of this study is to examine the effect of Klamin®, a nutraceutical containing phenylethylamine, phycocyanins, mycosporine-like aminoacids and aphanizomenon flos aquae-phytochrome on the learning and memory ability, the oxidative status and cerebral erythropoietin and its receptor EPO/EPOR system in prematurely senescent (PS) mice. A total of 28 PS mice, selected according to a prior T-maze test, and 26 non-prematurely senescent mice (NPS) mice were chosen. PS animals were divided into 3 groups and followed for 4 weeks: A) normal chow diet; B) added with Klamin® at 20 mg/kg/day (low dose); C) added with Klamin® at 100mg/kg/day (high dose). A further group of NPS mice given either normal food (group D) or high dose Klamin® (group E) was also considered. The behavioral procedures of spatial learning ability (Morris test) showed that PS mice had significantly longer learning time as compared to their NPS counterpart (p<0.01), but this effect was prevented especially in mice supplemented with high-dose Klamin® (p<0.05) which improved performances in NPS mice (p<0.05). High-dose Klamin® supplementation restored the depleted total thiol concentration in the brain observed in PS mice while normalizing their increased malonildialdehyde level (p<0.05). Moreover, the high-dosage only caused a significant upregulation of EPO/EPOR system both in PS and in NPS animals (p<0.05). Taken together, these data suggest that this specific alga Klamath extract has considerable antioxidant and adaptogenic properties, also through a stimulatory effect of cerebral EPO/EPO system.

Escherichia coli from retail meats carry genes associated with uropathogenic Escherichia coli, but are weakly invasive in human bladder cell culture

AIMS

The aim of this study was to determine the uropathogenic potential of Escherichia coli isolated from retail meats.

METHODS AND RESULTS

Two hundred E. coli isolates recovered from retail meats, which were previously identified molecularly as extraintestinal pathogenic E. coli, were investigated for the presence of 21 uropathogenic E. coli (UPEC) virulence-associated genes. Twenty-three E. coli isolates were selected based on their serogroups and the number of virulence genes they contained, and further characterized using multilocus sequence typing, and by tissue culture assays for adherence to and invasion of T-24 human bladder cells and for their induction of interleukin (IL)-6 secretion. All virulence genes tested, except afa/dra and hlyD, were detected among the E. coli isolates. Multilocus sequence typing analysis of 23 selected isolates revealed that 17 isolates belonged to STs associated with human UPEC. Nearly all 23 isolates exhibited lower level of adherence and invasion compared to a clinical strain, UPEC CFT073.

CONCLUSIONS

These observations suggested that a small proportion of E. coli isolates from retail meats carry uropathogenic associated virulence genes and thus may serve as a reservoir of these genes to UPEC in the human intestine. Their virulence potential seemed limited as they were only weakly invasive in human bladder cell culture.

SIGNIFICANCE AND IMPACT OF THE STUDY

These findings support the hypothesis that retail meat E. coli may play a role in relation to urinary tract infection (UTI) and may be considered in development of a UTI prevention strategy.

Uterine rupture during pregnancy

BACKGROUND

Despite great advances in modern obstetrics, uterine rupture (UR) remains one of the most frightening complications with high morbidity and mortality.

OBJECTIVE

To improve the diagnosis and management of UR.

RESULTS

We report two cases of UR. Case 1 was spontaneous UR and case 2 was associated with a scar in the patient's uterus. Interestingly, the ruptured scar was not a scar from a previous cesarean section; it was a scar that was associated with placenta accreta. The fetal heart rates in both cases were below 80 beats per minute after UR. The newborn in case 1 died soon after delivery, while the newborn in case 2 survived. Both women were healthy and were discharged from hospital two to three weeks after surgery.

CONCLUSION

UR can occur in a previously unscarred uterus or from a scar of a cesarean section or scars caused by other pathologic lesions in the uterus. Severe fetal bradycardia might be a strong indicator for UR. Such study will help obstetricians provide more careful measures to manage UR, so that its morbidity and mortality can be decreased.

Increased tau phosphorylation and beta amyloid in the hipocampus of mouse pups by early life lead exposure

The aim of this study was to investigate the effects of maternal lead exposure on the learning and memory ability and expression of tau protein phosphorylation (P-tau) and beta amyloid protein (Abeta) in hippocampus of mice offspring. Pb exposure initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at the concentrations of 0.1%, 0.5% and 1% groups. On the 21 th of postnatal day, the learning and memory ability of the mouse pups was tested by Water Maze test and the Pb levels in blood and hippocampus of the offspring were also determined. The expression of P-tau and Abeta in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than that of the control group ( P < 0.05). In Water Maze test, the performances of 0.5% and 1% groups were worse than that of the control group ( P < 0.05). The expression of P-tau and Abeta was increased in Pb exposed groups than that of the control group ( P < 0.05). Tau hyper-phosphorylation and Abeta increase in the hippocampus of pups may contribute to the impairment of learning and memory associated with maternal Pb exposure.

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.

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.