Methodology for analyzing accidents with radioactive material release with code EPZDose

A methodology for analyzing accidents with radioactive material release with EPZDose code was established. This code assesses doses and it is designed and developed by NTHU (National Tsing Hua University). To confirm the capacity of EPZDose, three postulated accident scenarios Taiwanese NPPs Chinshan (BWR/4) and Maanshan (PWR) are analyzed. All these scenarios are SBO (station blackout) transients because it is assumed that they result in a release of radioactive material. In this study, the source term data for EPZDose are taken from MELCOR or RASCAL calculations. In addition, calculated results of RASCAL code are compared with the results of EPZDose for these scenarios. The comparison show that the EPZDose predictions are consistent with the data of RASCAL. This indicates that the EPZDose has a respectable accuracy in the analysis of radioactive material release accidents.

959 Undertaking Core Surgical Training Less Than Full Time: A Qualitative Study of Experiences

Introduction

The Royal College of Surgeons identifies Less Than Full Time Training (LTFT) as a key factor in attracting excellent candidates at Core level. Previous evaluations of LTFT have, however, focused on ST3 and beyond. This study focuses on Core Surgical Training (CST), to determine how well it is delivering for LTFT trainees.

Method

Participants undertaking any part of CST LTFT were eligible. An electronic, self-administered questionnaire was accessed by participants.

Results

There were 11 participants. The majority (55%) rated the information available, which often related to more senior trainees, as poor. A third reported it ‘very difficult’ to arrange a LTFT training post. A significant proportion felt their access to operative experience was decreased and 45% reported feeling less confident. Positive aspects were improved work-life balance and being able to maintain a surgical career with a family. Suggestions for improvements included normalising LTFT in surgery to reduce stigma, having dedicated LTFT TPDs, clear pathways, and longer rotations.

Conclusions

Training LTFT offers many benefits – not least, increasing workforce diversity. However, for many, training LTFT at Core level produces additional stress, work and stigma. If the surgical community is serious about maintaining an excellent, diverse workforce, these issues should be tackled sooner rather than later.

Mechanistic and phylogenetic insights into actinobacteria-mediated oestrogen biodegradation in urban estuarine sediments

Steroidal oestrogens are often accumulated in urban estuarine sediments worldwide at microgram per gram levels. These aromatic steroids have been classified as endocrine disruptors and group 1 carcinogens. Microbial degradation is a naturally occurring mechanism that mineralizes oestrogens in the biosphere; however, the corresponding genes in oestrogen-degrading actinobacteria remain unidentified. In this study, we identified a gene cluster encoding several putative oestrogen-degrading genes (aed; actinobacterial oestrogen degradation) in actinobacterium Rhodococcus sp. strain B50. Among them, the aedA and aedB genes involved in oestrogenic A-ring cleavage were identified through gene-disruption experiments. We demonstrated that actinobacterial oestrone 4-hydroxylase (AedA) is a cytochrome P450-type monooxygenase. We also detected the accumulation of two extracellular oestrogenic metabolites, including pyridinestrone acid (PEA) and 3aα-H-4α(3'-propanoate)-7aβ-methylhexahydro-1,5-indanedione (HIP), in the oestrone-fed strain B50 cultures. Since actinobacterial aedB and proteobacterial edcB shared < 40% sequence identity, 4-hydroxyestrone 4,5-dioxygenase genes (namely aedB and edcB) could serve as a specific biomarker to differentiate the contribution of actinobacteria and proteobacteria in environmental oestrogen degradation. Therefore, 4-hydroxyestrone 4,5-dioxygenase genes and the extracellular metabolites PEA and HIP were used as biomarkers to investigate oestrogen biodegradation in an urban estuarine sediment. Interestingly, our data suggested that actinobacteria are active oestrogen degraders in the urban estuarine sediment.

Microbial degradation of steroid sex hormones: implications for environmental and ecological studies

Steroid hormones modulate development, reproduction and communication in eukaryotes. The widespread occurrence and persistence of steroid hormones have attracted public attention due to their endocrine-disrupting effects on both wildlife and human beings. Bacteria are responsible for mineralizing steroids from the biosphere. Aerobic degradation of steroid hormones relies on O2 as a co-substrate of oxygenases to activate and to cleave the recalcitrant steroidal core ring. To date, two oxygen-dependent degradation pathways - the 9,10-seco pathway for androgens and the 4,5-seco pathways for oestrogens - have been characterized. Under anaerobic conditions, denitrifying bacteria adopt the 2,3-seco pathway to degrade different steroid structures. Recent meta-omics revealed that microorganisms able to degrade steroids are highly diverse and ubiquitous in different ecosystems. This review also summarizes culture-independent approaches using the characteristic metabolites and catabolic genes to monitor steroid biodegradation in various ecosystems.

P4555Efficacy and safety of valsartan in children aged 1–5 years with hypertension, with or without chronic kidney disease: A 6-week randomised, multicentre, double-blind study followed by open-label phase

Background

Hypertension is a leading cause of disability and mortality worldwide. In the paediatric population, hypertension and chronic kidney disease (CKD) have raised significant health concern due to the risk of target organ damage similar to that seen in adults. Management of hypertension may therefore prevent decline in renal function and progression of CKD to end organ damage. Currently, there are no angiotensin receptor blockers approved in EU for hypertensive children younger than 6 years.

Purpose

To evaluate a dose-dependent reduction in mean systolic blood pressure (MSBP), safety and tolerability of two doses of valsartan (VAL) solution (0.25 mg/kg/day and 4 mg/kg/day) in children aged 1–5 years with hypertension with or without CKD.

Methods

This study comprised of a randomised multicentre double-blind (DB) double-dummy phase I (6-weeks) followed by an open-label (OL) titration phase II (20-weeks). In phase I, patients with history of hypertension were randomised 1:1 to receive VAL (0.25 or 4 mg/kg/day). Patients received VAL 1 mg/kg/day, optionally titrated to 2 mg/kg/day to 4 mg/kg/day based on BP response in phase II.

Results

Of the 127 randomised patients, 120 completed phase I, and 114 (55 CKD; 59 non-CKD) phase II. Baseline characteristics and demographics were comparable between treatment groups, and within the CKD and non-CKD subgroups.

In the DB phase, a clinically and statistically significant reduction was observed in MSBP at week 6 in the VAL 4 mg/kg group (8.5 mmHg) compared with the VAL 0.25 mg/kg group (4.1 mmHg, respectively; P=0.0157; baseline 113.3 mmHg vs. 116.0 mmHg, respectively). A positive dose-response relationship (i.e. slope for dose per body weight, mg/kg) was observed in MSBP reduction between the VAL 0.25 mg/kg and VAL 4.0 mg/kg group (P=0.0012).

In CKD patients, there was a significant reduction in MSBP from baseline to week 6 in the VAL 4 mg/kg group (9.2 mmHg) compared with the VAL 0.25 mg/kg group (1.2 mmHg; P=0.0096). MSBP reduction in non-CKD group was numerically larger with higher dose (7.8 mmHg vs 6.9 mmHg) but difference was not statistically significant (P=0.6531).

Incidence of adverse events (AEs) was lower with VAL 4 mg/kg (41.9%) vs VAL 0.25 mg/kg (51.6%); similar in the CKD (48.4%) and non-CKD (45.3%) subgroups and not dose dependent. The most common AE was respiratory tract infection (5.6%). Serious AEs occurred in 3.2% patients with similar incidence in each dose group. Discontinuation due to AEs was 1.6%, all in VAL 0.25 mg/kg group. One patient in low dose and 2 in high dose group had potassium values >5.5 mEq/L. Incidence of AEs in OL phase was 76.7% with pyrexia being most frequent (16.7%).

Conclusion

Valsartan produced clinically relevant reductions in BP with a statistically significant dose response in children aged 1–5 years with hypertension, with or without CKD. Long-term efficacy was maintained and was generally well tolerated.

Evaluation of control room habitability in case of LOCA for Maanshan NPP using codes RADTRAD, HABIT and ALOHA

The method for the evaluation of the control room habitability is presented in this paper with focus on Maanshan PWR nuclear power plant (NPP) using the codes RADTRAD, HABIT, and ALOHA. Therefore, this paper is divided into two parts: The first part is the evaluation of the cumulative dose at the control room, the exclusion area boundary (EAB) and the low population zone (LPZ) in case of an design basis loss of coolant accident (DBA/LOCA). For this first part, the Maanshan NPP models of the code RADTRAD/SNAP were used for the analysis. The second part is the evaluation of the control room habitability under the assumption of CO2 storage burst. For this part, the HABIT and ALOHA codes were used. As result it was seen that the RADTRAD calculation results are below the failure criteria of standard review plan (SRP) and 10 CFR 100.11. The HABIT and ALOHA results are below the R.G. 1.78 failure criteria. These results indicate that Maanshan NPP’ habitability can be maintained under the above conditions.

Oltipraz upregulates the nuclear factor (erythroid-derived 2)-like 2 [corrected](NRF2) antioxidant system and prevents insulin resistance and obesity induced by a high-fat diet in C57BL/6J mice

AIMS/HYPOTHESIS

We investigated whether oltipraz, a nuclear respiratory factor 2 alpha subunit (NRF2) activator, improves insulin sensitivity and prevents the development of obesity in mice.

METHODS

C57BL/6J mice were fed with a low-fat diet (10% of energy as fat), a high-fat diet (HFD) (45% of energy as fat) or a HFD with oltipraz for 28 weeks. The effects of oltipraz on body weight, fat content, glucose disposal, insulin signalling, metabolic profiles and endogenous NRF2 functional status in the three groups of mice were investigated.

RESULTS

Oltipraz prevented or significantly attenuated the effect of HFD on glucose disposal, body weight and fat gain. Impairment of protein kinase B/Akt phosphorylation in this HFD-fed mouse model in response to intraperitoneal insulin injection was observed in adipose tissue, but not in the muscles, accompanied by inhibition of AMP-activated protein kinase signalling and activation of p70S6 kinase, as well as reduced GLUT4 content. These defects were attenuated by oltipraz administration. Nuclear content of NRF2 in adipose tissue was reduced by HFD feeding, associated with increased Keap1 mRNA expression and reduced production of haem oxygenase-1 and superoxide dismutase, increased protein oxidation, decreased plasma reduced:oxidised glutathione ratio and the appearance of macrophage marker F4/80. These defects were also restored by oltipraz. Finally, oltipraz attenuated HFD-induced inducible nitric oxide synthase overproduction.

CONCLUSIONS/INTERPRETATION

Impairment of the endogenous redox system is important in the development of obesity and insulin resistance in chronic HFD feeding. NRF2 activation represents a potential novel approach in the treatment and prevention of obesity and diabetes.

Enols and other reactive species

Rapid advances in the chemistry of enols and other reactive species have been made possible recently by the development of methods for generating these short-lived substances in solution under conditions where they can be observed directly and their reactions can be monitored accurately. New laboratory techniques are described and a sample of the new chemistry they have made available is provided; special attention is given to ynols and ynamines and the remarkable effects that the carbon-carbon triple bonds of these substances have on their acid-base properties.

Plasma renin and the antihypertensive effect of the orally active renin inhibitor aliskiren in clinical hypertension

BACKGROUND

Aliskiren is the first in a new class of orally effective renin inhibitors for the treatment of hypertension.

METHODS

In 569 patients with mild-to-moderate hypertension, blood pressure (BP), plasma renin activity (PRA) and plasma renin concentration (PRC) were measured before and after 8 weeks of double-blind treatment with once-daily oral doses of aliskiren (150, 300 or 600 mg), irbesartan 150 mg or placebo.

RESULTS

Aliskiren 150, 300 and 600 mg and irbesartan 150 mg significantly reduced mean cuff sitting systolic BP (SBP) from baseline (p < 0.001 vs. placebo). Aliskiren 150, 300 and 600 mg significantly reduced geometric mean PRA by 69%, 71% and 75% from baseline respectively (p < 0.05 vs. placebo). Irbesartan 150 mg significantly increased PRA by 109% (p < 0.05 vs. placebo). Aliskiren dose-dependently increased PRC from baseline by 157%, 246% and 497%, at 150, 300 and 600 mg respectively, compared with a 9% decrease with placebo (p < 0.05). PRC increased significantly more with aliskiren 300 and 600 mg compared with irbesartan 150 mg (105%; p < 0.05). Regression analysis showed no significant correlations between baseline PRA and changes in SBP in any of the treatment groups, but interestingly, the slopes of the regression lines between changes in SBP and log-transformed baseline PRA were +2.0 for placebo and -1.5, -1.8 and -2.3 for aliskiren 150, 300 and 600 mg respectively. The slope for irbesartan 150 mg (-1.4) was similar to that for aliskiren 150 mg.

CONCLUSIONS

Aliskiren reduces SBP and PRA and increases PRC dose-dependently. In contrast, irbesartan reduces SBP but increases both PRC and PRA. As PRA is a measurement of angiotensin I-generating capacity, PRA can be used for measuring the ability of an antihypertensive agent to prevent the generation or action of Ang II, either directly (renin inhibitors, beta-blockers, central alpha(2)-agonists) or indirectly (AT(1)-receptor blockers, ACE inhibitors).

Preferential chemosensitivity to gemcitabine by cyclin E overexpression in human gastric cancers

21020

Background: Exploration of molecular determinants for chemosensitivity is the key element of personalized cancer therapy. Cyclin E is a major G1-phase cyclin, together with the CDK2, which mediates phosphorylation and functional inactivation of Rb protein. Cyclin E overexpression has been demonstrated in a variety of cancers, including human gastric cancers (GC), while its biologic significance in drug therapy remains unclear. Previously, we have demonstrated that cyclin D1 overexpression plays an important role in differential chemosensitivity of human GC cells (Proc Am Assoc Cancer Res 2004; 45: abstract 4888). In this study, we examine the roles between cyclin E overexpression and chemosensitivity of human GC cells. Methods: Compared human gastric cancer cells (NCI-N87) with stably transfected cells (N87-CyE), which have 2-fold overexpression of cyclin E, the IC50 for gemcitabine (2'-2'-difluoro- deoxycytidine, dFdC) was more than 1-log lower in N87-CyE (17.0 ± 2.7 nM) than N87 cells (113.7 ± 6.5 nM) by MTT colorimetric cytotoxicity assay. In contrast, the N87-CyE cells are only slightly more chemosensitive to taxanes (paclitaxel and docetaxel), and confer largely identical chemosensitivity to 5-FU, cisplatin, and irinotecan (CPT-11). We applied RNA interference (RNAi) of cyclin E to N87 cells. The stably transfected N87-CyE/RNAi cells readily confer gemcitabine resistance with the IC50 for gemcitabine of 124.5 ± 1.6 nM. Results: Gemcitabine-induced apoptosis in N87, N87-CyE, or N87-CyE/RNAi cells was shown in either caspase-3 or PARP (poly ADP-ribose polymerase) cleavage assay by Western blotting, and Annexin-V-FITC apoptosis detection by flowcytometry. The threshold concentration of gemcitabine for caspase-3 and PARP cleavage was 10–25 nM for N87-CyE, and 100–200 nM for N87 or N87-CyE/RNAi, respectively. Conclusions: Our data demonstrate that preferential chemosensitivity to gemcitabine by cyclin E overexpression in gastric cancer cells. Gemcitabine-induced apoptosis is enhanced by cyclin E overexpression, while is reduced by RNAi of cyclin E. Further studies for potential clinical use of gemcitabine in personalized chemotherapy for cyclin E or cyclin D1-overexpressing GC are warranted (supported by the grants of NHRI-CN-CA9201S, Taiwan).

No significant financial relationships to disclose.

The 2-Oxocyclobutanecarboxylic Acid Keto−Enol System in Aqueous Solution: A Remarkable Acid-Strengthening Effect of the Cyclobutane Ring

Flash photolysis of 2-diazocyclopentane-1,3-dione in aqueous solution produced 2-oxocyclobutylideneketene, which underwent hydration to the enol of 2-oxocyclobutanecarboxylic acid; the enol then isomerized to the keto form of this acid. Rates of the ketene and enol reactions were measured in acid, base, and buffer solutions across the acidity range [H+] = 10(-1)-10(-13) M, and analysis of these data, together with rates of enolization of the keto form of 2-oxocyclobutanecarboxylic acid determined by bromine scavenging, gave keto-enol equilibrium constants as well as acidity constants of the keto and enol forms. The keto-enol equilibrum constants proved to be 2 orders of magnitude less than those reported previously for the next higher homolog, 2-oxocyclopentanecarboxylic acid, reflecting the difficulty of inserting a carbon-carbon double bond into a small, strained carbocyclic ring. The acidity constant of the enol group of 2-oxocyclobutanecarboxylate ion, on the other hand, is greater, by 4 orders of magnitude, than that of the corresponding enol in the cyclopentyl system. This remarkable increase in acidity with diminishing ring size is consistent with the enhanced s character of the orbitals used to make the exocyclic bonds of the smaller cyclobutane ring.

The 2-oxo-3,3,5,5-tetramethylcyclopentanecarboxylic acid keto–enol system in aqueous solution — Generation of the enol by flash photolytic Wolff rearrangement of 2-diazo-4,4,6,6-tetramethylcyclohexane-1,3-dione followed by hydration of the acylketene thus formed

Flash photolysis of 2-diazo-4,4,6,6-tetramethylcyclohexane-1,3-dione in aqueous solution produced 2-oxo-3,3,5,5-tetramethylcyclopentylideneketene, which underwent hydration to the enol of 2-oxo-3,3,5,5-tetramethylcyclo pentanecarboxylic acid; the enol then isomerized to the keto form of the acid. Rates of hydration of the ketene and rates of ketonization of the enol were measured in perchloric acid, sodium hydroxide, and buffer solutions, and rate profiles were constructed. Rates of enolization of 2-oxo-3,3,5,5-tetramethylcyclopentanecarboyxlic acid were also measured, using bromine to scavenge the enol as it formed, and rates of enolization and ketonization were then combined to give the keto–enol equilibrium constant pKE = 1.65. This and other results are discussed in comparison with the behavior of the unmethylated 2-oxocyclopentanecarboxylic acid system.Key words: flash photolysis, photo-Wolff reaction, ketene hydration, enolization, ketonization, keto–enol equilibria, β-oxocarboxylic acids.

Generation of 6-methylene-2,4-cyclohexadienylidene ketene by flash photolysis of benzocyclobutenone in aqueous solution and study of the reactions of this ketene in that medium

Flash photolysis of benzocyclobutenone in aqueous solution produced a transient species with a microsecond lifetime whose rates of decay were measured in perchloric acid, sodium hydroxide, and buffer solutions over the acidity range [H+] 1 × 10–13 – 100 M. This produced a rate profile, isotope effects, and buffer behaviour typical of ketene reactions, and that, together with product identification, served to identify this transient as 6-methylene-2,4-cyclohexadienylidene ketene, formed by electrocyclic opening of the four-membered ring of benzocyclobutenone. Comparison of rates of reaction of this ketene with those of its saturated analog, pentamethyleneketene, produced some expected as well as some unexpected results. Key words: cyclobutenone chemistry, electrocyclic ring opening, ketene hydration, rate profile, solvent isotope effects.

The mandelamide keto-enol system in aqueous solution. Generation of the enol by hydration of phenylcarbamoylcarbene

Flash photolysis of diazophenylacetamide in aqueous solution produced phenylcarbamoylcarbene, whose hydration generated a transient species that was identified as the enol isomer of mandelamide. This assignment is based on product identification and the shape of the rate profile for decay of the enol transient, through ketonization to its carbonyl isomer, as well as by the form of acid-base catalysis of and solvent isotope effects on the decay reaction. Rates of enolization of mandelamide were also determined, by monitoring hydrogen exchange at its benzylic position, and these, in combination with the ketonization rate measurements, gave the keto-enol equilibrium constant pK(E) = 15.88, the acidity constant of the enol ionizing as an oxygen acid, pQ(E)(a)= 8.40, and the acidity constant of the amide ionizing as a carbon acid pQ(K)(a)= 24.29. (These acidity constants are concentration quotients applicable at ionic strength = 0.10 M.) These results show the enol content and carbon acid strength of mandelamide, like those of mandelic acid and methyl mandelate, to be orders of magnitude less than those of simple aldehydes and ketones; this difference can be attributed to resonance stabilization of the keto isomers of mandelic acid and its ester and amide derivatives, through electron delocalization into their carbonyl groups from the oxygen and nitrogen substituents adjacent to these groups. The enol of mandelamide, on the other hand, again like the enols of mandelic acid and methyl mandelate, is a substantially stronger acid than the enols of simple aldehydes and ketones. This difference can be attributed to the electronegative nature of the oxygen and nitrogen substituents geminal to the enol hydroxyl group in the enols of mandelic acid and its derivatives; in support of this, the acidity constants of these enols correlate well with field substituent constants of these geminal groups.

Flash photolytic generation and study of p-quinone methide in aqueous solution. An estimate of rate and equilibrium constants for heterolysis of the carbon-bromine bond in p-hydroxybenzyl bromide

Flash photolysis of p-hydroxybenzyl acetate in aqueous perchloric acid solution and formic acid, acetic acid, biphosphate ion, and tris(hydroxymethyl)methylammonium ion buffers produced p-quinone methide as a short-lived species that underwent hydration to p-hydroxybenzyl alcohol in hydronium ion catalyzed (k(H(+)) = 5.28 x 10(4) M(-1) s(-1)) and uncatalyzed (k(uc) = 3.33 s(-1)) processes. The inverse nature of the solvent isotope effect on the hydronium ion-catalyzed reaction, k(H(+))/k(D(+)) = 0.41, indicates that this process occurs by rapid and reversible protonation of the quinone methide on its carbonyl carbon atom, followed by rate-determining capture of the p-hydroxybenzyl carbocation so produced by water, while the magnitude of the rate constant on the uncatalyzed process indicates that this reaction occurs by simple nucleophilic addition of water to the methylene group of the quinone methide. p-Quinone methide also underwent hydronium ion-catalyzed and uncatalyzed nucleophilic addition reactions with chloride ion, bromide ion, thiocyanate ion, and thiourea. The solvent isotope effects on the hydronium ion-catalyzed processes again indicate that these reactions occurred by preequilibrium mechanisms involving a p-hydroxybenzyl carbocation intermediate, and assignment of a diffusion-controlled value to the rate constant for reaction of this cation with thiocyanate ion led to K(SH) = 110 M as the acidity constant of oxygen-protonated p-quinone methide. In a certain perchloric acid concentration range, the bromide ion reaction became biphasic, and least-squares analysis of the kinetic data using a double-exponential function provided k(Br(-)) = 3.8 x 10(8) M(-1) s(-1) as the rate constant for nucleophilic capture of the p-hydroxybenzyl carbocation by bromide ion, k(ionz) = 8.5 x 10(2) s(-1) for ionization of the carbon-bromine bond of p-hydroxybenzyl bromide, and K = 4.5 x 10(5) M(-1) as the equilibrium constant for the carbocation-bromide ion combination reaction, all in aqueous solution at 25 degrees C. Comparisons are made of the reactivity of p-quinone methide with p-quinone alpha,alpha-bis(trifluoromethyl)methide as well as p-quinone methide with o-quinone methide.