Simalikalactone E (SkE), a new weapon in the armamentarium of drugs targeting cancers that exhibit constitutive activation of the ERK pathway

Simalikalactone E (SkE) is a quassinoid extracted from a widely used Amazonian antimalarial remedy. Although SkE has previously been shown to have cytostatic and/or cytotoxic activities in some tumor cell lines, its mechanism of action has not yet been characterized. We show here that SkE in the high nanomolar range inhibited the growth of various leukemic and solid tumor cell lines. Importantly, SkE was highly efficient at inhibiting chronic myelogenous leukemia (CML) cells that exhibit constitutive activation of the MAPK pathway and, accordingly, it impaired the phosphorylation of ERK1/2. SkE also abrogated MEK1/2 and B-Raf phosphorylation but had no effect on Ras activity. Moreover, SkE was particularly effective against melanoma cell lines carrying the B-Raf-V600E mutation. Importantly, SkE resensitized the PLX-4032-resistant 451Lu melanoma cell line (451Lu-R) and was more efficient than U0126, a MEK inhibitor, and PLX-4032 (PLX) at inducing the apoptosis of two Hairy Cell Leukemia (HCL) patient samples carrying the B-Raf-V600E mutation. Finally, SkE was as efficient as imatinib at inhibiting tumor formation in a xenograft model of CML cells in athymic mice. In conclusion, we show that SkE, a very potent inhibitor of B-Raf-V600E, is highly effective against cancer cell lines that exhibit constitutive activation of the ERK1/2 pathway.

Utilising laboratory experiments as a first step to introduce primary sludge hydrolysis in full-scale

Laboratory experiments have been utilised as a tool to determine the possible yield of soluble COD and VFAs from settled influent and preprecipitated sludge at Klagshamn wastewater treatment plant and to determine the degradability of the organic matter. The release of ammonium and orthophosphate from the hydrolysed sludge has been estimated. It is possible to produce soluble organic matter of good quality from settled influent and preprecipitated sludge at Klagshamn WWTP. Denitrification rates of 3.1 mg NO3-N/(g VSS x h) were found for the hydrolysate in laboratory tests. Owing to the low phosphate concentrations in the hydrolysate from preprecipitated sludge, it shows a potential for postdenitrification despite stringent phosphorus outlet demands. Calculations based on data gained from the laboratory experiments show that about 50% of the external carbon source used today can be saved with minor changes in the plant operation except that the hydrolysis has to be established. Based on these findings, full-scale experiments with internal hydrolysis in the primary clarifiers were scheduled in one of the two lines at Klagshamn WWTP for the summer of 2007.

Biomass adaptation to complex substrate degradation in membrane bioreactors: appropriated operating conditions

The aim of this work is to analyse the biological performances of two immersed membranes bioreactors focusing on the biomass adaptation to complex substrate degradation and the performance in term of permeate quality. Two influents were selected: a synthetic complex influent (acetate/Viandox, MBR1) and a real seafood processing wastewater (surimi product, MBR2). The MBR systems were operated for long periods without any sludge extraction except for sampling. Organic matter removal, sludge production and quality of the treated wastewater were analysed and studied. COD removal efficiencies after a period of biomass adaptation were higher than 97% and 95% for the synthetic and real wastewater respectively. In both cases, the COD of the treated wastewater was lower than 50 mg.L(-1). In spite of salt concentration in the real wastewater a biomass adaptation process occurs. In the overall operational period, a 0.058 gCOD P.gCOD T(-1) and a 0.12 gCOD P.gCOD T(-1) observed sludge yields were obtained for the MBR1 and MBR2 respectively. These values are approximately 5 to 10 times lower than those measured in conventional activated sludge process. These results showed that the presence of particular and some of non-easily degradable compounds in the influent of MBR2 didn't limit the performance of MBR in term of COD removal achieved. The results have also confirmed the excellent permeate quality for water reuse from MBRs systems.

Do zopiclone, zolpidem and flunitrazepam have residual effects on simulated task of collision anticipation?

Few studies have addressed the modifications in visual information processing brought about by taking hypnotic substances. The present experiment with healthy subjects investigated the residual effects of taking a single night-time dose of hypnotics on collision anticipation capacities the next morning. Visual sequences simulated the movement of a driver approaching an intersection where another vehicle was arriving. Ten participants had to estimate, as quickly as possible, whether the other vehicle would arrive before or after them at the intersection. They were tested after having taken a capsule of zolpidem (10 mg), zopiclone (7.5 mg), flunitrazepam (1 mg) or a placebo. The results show no residual effects of the molecules. Only flunitrazepam, a benzodiazepine with a long half-life, appears to cause subjects to focus their attention on an element which, while relevant for the task (a road sign playing the role of a spatial reference), is not used correctly.

Is visual anticipation of collision during self-motion related to perceptual style?

We have previously shown that during self-motion in car driving situations, the perception of another car's trajectory relies both on global visual information such as the optical flow field, and on local visual information such as the optical motion of the other car and the relative optical motion of the other car with respect to fixed elements in the environment. Here, we studied the environmental factors that contribute to perceptual judgements in relation to the observer's perceptual style (visual-field dependence vs. visual-field independence). In an experiment, observers were presented with visual scenes corresponding to the curvilinear self-motion of a driver approaching an intersection where another vehicle was arriving perpendicularly. The factors manipulated were the presence or absence of a spatial reference point (road sign near the intersection), environmental complexity ("road" or "spot" scenes), and the degree of field dependence/independence. Nine field-independent (FI) subjects and seven field-dependent (FD) subjects were asked to predict whether the other vehicle would reach the intersection before or after they would. Their responses were analyzed. Overall, subjects' judgements were more accurate with road environments and with a road sign, suggesting that the relative motion of the other vehicle with respect to fixed elements in the environment provides additional useful information. FI subjects were significantly more accurate than FD subjects, suggesting that the former are better at picking up relevant dynamic information in a complex environment.

Ultrasound findings in renal parenchymal disease: comparison with histological appearances

Ultrasound examination was carried out in 55 patients undergoing renal biopsy for suspected renal parenchymal disease. Analysis of sonographic and histological findings showed statistically significant positive correlations between renal size and the extent of glomerular hyper-cellularity and crescent formation and between cortical echogenicity and severity of glomerular sclerosis, crescent formation, interstitial inflammatory cell infiltration, tubular atrophy and interstitial fibrosis. Positive correlation was also observed between prominence of the medullary pyramids and glomerular sclerosis. The most marked sonographic abnormalities were seen in proliferative (including crescentic) glomerulonephritis, diabetic glomerulosclerosis and tubulo-interstitial nephritis. IgA, membranous and minimal change nephropathy were less likely to be associated with sonographic abnormalities. We conclude that certain sonographic appearances in renal parenchymal disease reflect the presence and severity of light microscopical abnormalities but, although ultrasound assessment provides a high positive predictive value for renal parenchymal disease, specific conditions cannot be distinguished.

Deaths from volatile substance abuse in those under 18 years: results from a national epidemiological study

The epidemiology of deaths from volatile substance abuse (VSA) in those under 18 years that occurred in the UK from 1981-90 is described. The analysis of deaths is based on a national register, which has information obtained from a regular survey of coroners, the Office of Population Censuses and Surveys, and a press clippings agency. Altogether 605 people under 18 died from VSA during this period. Seventy per cent of deaths occurred between the ages of 14 and 16. The largest number of deaths were attributed to butane gas lighter refills. There was a large north-south gradient in age specific mortality ratios (Scotland 180, south east England 87) and nearly four times as many deaths occurred in social class V compared with social class I. Deaths from VSA are an important and preventable cause of deaths in those under 18. Strategies aimed at prevention should include measures to reduce experimentation, intervention to reduce socioeconomic deprivation, and health education campaigns aimed at schools and parents.

Are viral warts seen more commonly in children with eczema?

BACKGROUND AND DESIGN

We sought to test the hypothesis that warts are seen more commonly in individuals with eczema by analyzing skin examination data from a national birth cohort study of 9263 British children born between March 3 and 9, 1958.

RESULTS

Warts were seen less frequently in those with visible eczema at ages 11 and 16 years (relative risk, 0.60; 95% confidence intervals, 0.37 to 0.95; P = .03). This inverse association persisted after adjustment for potential confounders and was consistent within each age and sex group for children with a history of eczema who did not have visible eczema at the time of examination and for children with asthma/wheezy bronchitis regardless of eczema status. Visible acne or psoriasis was not associated with a decreased prevalence of warts.

CONCLUSIONS

These findings contradict previous suggestions of an increased risk of viral warts in atopic eczema and raise new questions regarding the role of cell-mediated immunity in atopic subjects.

The descriptive epidemiology of warts in British schoolchildren

This study set out to determine the prevalence and predictors of warts in British schoolchildren by analysing medical examination data from a national birth cohort study of 9263 British children born 3-9 March 1958. The prevalence of visible warts, according to a medical officer, at the age of 11 was 3.9% (95% confidence intervals 3.5-4.3) and 4.9% (95% confidence intervals 4.5-5.4) at 16. Of the 364 children noted to have warts at the age of 11,337 (93%) no longer had warts at 16. Residence in the south of Britain, having a father with a non-manual occupation, being an only child, and belonging to an ethnic group other than white European were all associated with a decreased risk of visible warts. Region of residence was the strongest predictor of wart prevalence. There were no sex differences in wart prevalence. Warts represent a common source of morbidity in British schoolchildren. Future studies should take into account age, regional factors, social class, family size and ethnic group when comparing wart sufferers with other subjects.

Altered vitamin B12 metabolism in fibroblasts from a patient with megaloblastic anemia and homocystinuria due to a new defect in methionine biosynthesis

Cultured fibroblasts from a recently described patient with homocystinuria and megaloblastic anemia of infancy without methylmalonic aciduria were previously shown to have normal cobalamin uptake and a specific decrease in the proportion of intracellular methylcobalamin. As in control cells but unlike in those from patients with combined homocystinuria and methylmalonic aciduria (cobalamin C and cobalamin D), accumulated 57Co-labeled cobalamin was bound in appropriate amounts and proportion to intracellular binders which are known to be the two vitamin B12-dependent enzymes, methionine synthetase and methylmalonyl-CoA mutase. Despite the association of a normal quantity of intracellular cobalamin with methionine synthetase, the proportion of intracellular cobalamin which was methyl-B12 was below normal and in the range observed in cobalamin C and D cells. This methyl-B12 was decreased by exposure of fibroblasts in culture to nitrous oxide as was observed with control cells. Exposure of control fibroblasts during culture, but not of fibroblasts from this patient, to nitrous oxide significantly reduced the holoenzyme activity of methionine synthetase assayed in cell extracts. In addition, although methionine synthetase activity in cell extracts of control and cells from the patient were similar in the presence of standard assay concentrations of thiols, at low thiol concentrations, methionine synthetase activity in extracts of cells from the patient was much lower than in control extracts. Mixing of control patient extracts corrected this decreased activity in excess of that explained by addition of the individual activities added. The defect of this patient appears to be in a reducing system required for methionine synthesis.

Differential effects of folinic acid and glycine, adenosine, and thymidine as rescue agents in methotrexate-treated human cells in relation to the accumulation of methotrexate polyglutamates

By converting methotrexate (MTX) into poly-gamma-glutamyl derivatives, cultured human fibroblasts accumulated high intracellular levels of drug. Once polyglutamates had been formed, DNA synthesis and cell growth remained suppressed even after MTX had been removed from the culture medium. Co-cultivation of cells with MTX and folinic acid reversed the effect of MTX on polyglutamate formation, DNA synthesis, and cell growth. However, if folinic acid was added to the culture medium following a preincubation in methotrexate, DNA synthesis initially remained inhibited and cell growth was only gradually restored. Co-cultivation of cells with 0.67 mM glycine, 37.5 micrometers adenosine, and 41.3 micrometers thymidine (GAT) and MTX did not prevent polyglutamate formation but allowed cells to grow. If GAT was removed from the culture medium along with MTX, cell growth and DNA synthesis were inhibited. If GAT was added to the culture medium following growth in MTX, cell growth recovered. These studies differentiate the effects of GAT and folinic acid treatment. Folinic acid prevented MTX polyglutamate accumulation and reversed the effects of MTX on cell growth when present along with MTX in the cultures. Folinic acid was only partially effective in circumventing the MTX-induced block in folate metabolism when added after pretreatment with MTX. In contrast, GAT allowed growth of cells both in the presence of MTX and after a preincubation in MTX. In contrast, GAT allowed growth of cells both in the presence of MTX and after a preincubation in MTX. However, co-incubation in MTX plus GAT resulted in the accumulation of polyglutamates and a sustained inhibition of cell growth and DNA synthesis upon removal of both MTX and GAT from the culture medium.

Comparative activity of arylsulphatases A and B on two synthetic substrates

Rat liver and human skin fibroblasts arylsulphatase A and B activities on both 4-methylumbelliferyl sulphate and 4-nitrocatechol sulphate were compared. The intracellular distribution of activity differed markedly when 4-methylumbelliferyl sulphate was used from that observed with 4-nitrocatechol sulphate. No discrimination between control and metachromatic leucodystrophy or mucopolysaccharidosis (type VI) could be achieved when 4-methylumbelliferyl sulphate was used as substrate. These results contrast sharply with those obtained with 4-nitrocatechol sulphate and cast doubt on the validity of 4-methylumbelliferyl sulphate as substrate for the determination of arylsulphatase A and B activities.