A unique automation platform for measuring low level radioactivity in metabolite identification studies

Generation and interpretation of biotransformation data on drugs, i.e. identification of physiologically relevant metabolites, defining metabolic pathways and elucidation of metabolite structures, have become increasingly important to the drug development process. Profiling using (14)C or (3)H radiolabel is defined as the chromatographic separation and quantification of drug-related material in a given biological sample derived from an in vitro, preclinical in vivo or clinical study. Metabolite profiling is a very time intensive activity, particularly for preclinical in vivo or clinical studies which have defined limitations on radiation burden and exposure levels. A clear gap exists for certain studies which do not require specialized high volume automation technologies, yet these studies would still clearly benefit from automation. Use of radiolabeled compounds in preclinical and clinical ADME studies, specifically for metabolite profiling and identification are a very good example. The current lack of automation for measuring low level radioactivity in metabolite profiling requires substantial capacity, personal attention and resources from laboratory scientists. To help address these challenges and improve efficiency, we have innovated, developed and implemented a novel and flexible automation platform that integrates a robotic plate handling platform, HPLC or UPLC system, mass spectrometer and an automated fraction collector.     

Longitudinal qPCR Study of the Dynamics of L. crispatus,L. iners,A. vaginae, (Sialidase Positive) G. vaginalis,and P. bivia in the Vagina

Background

To obtain more detailed understanding of the causes of disturbance of the vaginal microflora (VMF), a longitudinal study was carried out for 17 women during two menstrual cycles.

Methods

Vaginal swabs were obtained daily from 17 non-pregnant, menarchal volunteers. For each woman, Gram stains were scored, the quantitative changes of 5 key vaginal species, i.e. Atopobium vaginae, Lactobacillus crispatus, L. iners, (sialidase positive) Gardnerella vaginalis and Prevotella bivia were quantified with qPCR and hydrogen-peroxide production was assessed on TMB+ agar.

Results

Women could be divided in 9 subjects with predominantly normal VMF (grades Ia, Ib and Iab, group N) and 8 with predominantly disturbed VMF (grades I-like, II, III and IV, group D).VMF was variable between women, but overall stable for most of the women. Menses were the strongest disturbing factor of the VMF. L. crispatus was present at log7–9 cells/ml in grade Ia, Iab and II VMF, but concentrations declined 100-fold during menses. L. crispatus below log7 cells/ml corresponded with poor H₂O₂-production. L. iners was present at log 10 cells/ml in grade Ib, II and III VMF. Sialidase negative G. vaginalis strains (average log5 cells/ml) were detected in grade I, I-like and IV VMF. In grade II VMF, predominantly a mixture of both sialidase negative and positive G. vaginalis strains (average log9 cells/ml) were present, and predominantly sialidase positive strains in grade III VMF. The presence of A. vaginae (average log9 cells/ml) coincided with grade II and III VMF. P. bivia (log4–8 cells/ml) was mostly present in grade III vaginal microflora. L. iners, G. vaginalis, A. vaginae and P. bivia all increased around menses for group N women, and as such L. iners was considered a member of disturbed VMF.

Conclusions

This qPCR-based study confirms largely the results of previous culture-based, microscopy-based and pyrosequencing-based studies.     

Dipeptides as Leaving Group in the Enzyme‐Catalyzed DNA Synthesis

Conjugates of 2′‐deoxyadenosine monophosphate with dipeptides have been synthesized and tested as substrates for several polymerases. Although the incorporation efficiency is not very high, it demonstrates that some of these dipeptides can be accommodated in the active site of polymerases and function as leaving groups in the enzymatic synthesis of DNA.     

A new brace treatment similar for adolescent scoliosis and kyphosis based on restoration of thoracolumbar lordosis. Radiological and subjective clinical results after at least one year of treatment

Study design

A prospective treatment study with a new brace was conducted Objective. To evaluate radiological and subjective clinical results after one year conservative brace treatment with pressure onto lordosis at the thoracolumbar joint in children with scoliosis and kyphosis.

Summary of background data

Conservative brace treatment of adolescent scoliosis is not proven to be effective in terms of lasting correction. Conservative treatment in kyphotic deformities may lead to satisfactory correction. None of the brace or casting techniques is based on sagittal forces only applied at the thoracolumbar spine (TLI= thoracolumbar lordotic intervention). Previously we showed in patients with scoliosis after forced lordosis at the thoracolumbar spine a radiological instantaneous reduction in both coronal curves of double major scoliosis.

Methods

A consecutive series of 91 children with adolescent scoliosis and kyphosis were treated with a modified symmetric 30 degrees Boston brace to ensure only forced lordosis at the thoracolumbar spine. Scoliosis was defined with a Cobb angle of at least one of the curves [greater than or equal to] 25 degrees and kyphosis with or without a curve <25 degrees in the coronal plane. Standing radiographs were made i) at start, ii) in brace at beginning and iii) after one year treatment without brace.

Results

Before treatment start ??in brace?? radiographs showed a strong reduction of the Cobb angles in different curves in kyphosis and scoliosis groups (sagittal n = 5 all p < 0.001, pelvic obliquity p < 0.001). After one year of brace treatment in scoliosis and kyphosis group the measurements on radiographs made without brace revealed an improvement in 3 Cobb angles each.

Conclusion

Conservative treatment using thoracolumbar lordotic intervention in scoliotic and kyphotic deformities in adolescence demonstrates a marked improvement after one year also in clinical and postural criteria. An effect not obtained with current brace techniques.     

Nitric oxide reduction in BioDeNOx reactors: kinetics and mechanism

Biological reduction of nitric oxide (NO) to di-nitrogen (N(2)) gas in aqueous Fe(II)EDTA(2-) solutions is a key reaction in BioDeNOx, a novel process for NOx removal from flue gases. The mechanism and kinetics of the first step of NO reduction, that is, the conversion of NO to N(2)O, was determined in batch experiments using various types of inocula. Experiments were performed in Fe(II)EDTA(2-) medium (5-25 mM) under BioDeNOx reactor conditions (55 degrees C, pH 7.2 +/- 0.2) with ethanol as external electron donor. BioDeNOx reactor mixed liquor gave the highest NO reduction rates (+/-0.34 nmol s(-1) mg(prot)(-1)) with an estimated K(m) value for NO lower than 10 nM. The specific NO (to N(2)O) reduction rate depended on the NO (aq) and Fe(II)EDTA(2-) concentration as well as the temperature. The experimental results, complemented with kinetic and thermodynamic considerations, show that Fe(II)EDTA(2-), and not ethanol, is the primary electron donor for NO reduction, that is, the BioDeNOx reactor medium (the redox system Fe(II)EDTA(2-)/Fe(III)EDTA(-)) interferes with the NO reduction electron transfer chain and thus enhances the NO denitrification rate.     

Anaerobic methanethiol degradation and methanogenic community analysis in an alkaline (pH 10) biological process for liquefied petroleum gas desulfurization

Anaerobic methanethiol (MT) degradation by mesophilic (30 degrees C) alkaliphilic (pH 10) communities was studied in a lab-scale Upflow Anaerobic Sludge Bed (UASB) reactor inoculated with a mixture of sediments from the Wadden Sea (The Netherlands), Soap Lake (Central Washington), and Russian soda lakes. MT degradation started after 32 days of incubation. During the first 252 days, complete degradation was achieved till a volumetric loading rate of 7.5 mmol MT/L/day, and sulfide, methane, and carbon dioxide were the main reaction products. Temporary inhibition of MT degradation occurred after MT peak loads and in the presence of dimethyl disulfide (DMDS), which is the autooxidation product of MT. From day 252 onwards, methanol was dosed to the reactor as co-substrate at a loading rate of 3-6 mmol/L/day to stimulate growth of methylotrophic methanogens. Methanol was completely degraded and also a complete MT degradation was achieved till a volumetric loading rate of 13 mmol MT/L/day (0.77 mmol MT/gVSS/day). However, from day 354 till the end of the experimental run (day 365), acetate was formed and MT was not completely degraded anymore, indicating that methanol-degrading homoacetogenic bacteria had partially outcompeted the methanogenic MT-degrading archea. The archeal community in the reactor sludge was analyzed by DGGE and sequencing of 16S rRNA genes. The methanogenic archea responsible for the degradation of MT in the reactor were related to Methanolobus oregonensis. A pure culture, named strain SODA, was obtained by serial dilutions in medium containing both trimethyl amine and dimethyl sulfide (DMS). Strain SODA degraded MT, DMS, trimethyl amine, and methanol. Flow sheet simulations revealed that for sufficient MT removal from liquefied petroleum gas, the extraction and biological degradation process should be operated above pH 9.     

Distribution of 3-hydroxy oxylipins and acetylsalicylic acid sensitivity in Cryptococcus species

Using a well tested antibody specific for 3-hydroxy oxylipins, we mapped the presence of these oxylipins in selected Cryptococcus (Filobasidiella) species. Immunofluorescence microscopy studies revealed that these compounds are deposited on cell wall surfaces, appendages, and collarettes. In vitro studies revealed that growth of Cryptococcus species was inhibited by acetylsalicylic acid (which is known to inhibit mitochondrial function, including the production of 3-hydroxy oxylipins) at concentrations as low as 1 mmol/L. The results suggest that acetylsalicylic acid is effective in controlling the growth of tested pathogens, probably by targeting their mitochondria. This study further expands the known function of this anti-inflammatory drug as anti-fungal agent.     

Discovery of novel potent and selective dipeptide hepatitis C virus NS3/4A serine protease inhibitors

Starting from the previously reported HCV NS3/4A protease inhibitor BILN 2061, we have used a fast-follower approach to identify a novel series of HCV NS3/4A protease inhibitors in which (i) the P3 amino moiety and its capping group have been truncated, (ii) a sulfonamide is introduced in the P1 cyclopropyl amino acid, (iii) the position 8 of the quinoline is substituted with a methyl or halo group, and (iv) the ring size of the macrocycle has been reduced to 14 atoms. SAR analysis performed with a limited set of compounds led to the identification of N-{17-[8-chloro-2-(4-isopropylthiazol-2-yl)-7-methoxyquinolin-4-yloxy]-2,14-dioxo-3,15-diazatricyclo [13.3.0.0 [Bartenschlager, R.; Lohmann, V. J. Gen. Virol. 2000, 81, 1631; Vincent Soriano, Antonio Madejon, Eugenia Vispo, Pablo Labarga, Javier Garcia-Samaniego, Luz Martin-Carbonero, Julie Sheldon, Marcelle Bottecchia, Paula Tuma, Pablo Barreiro Expert Opin. Emerg. Drugs, 2008, 13, 1-19]]octadec-7-ene-4-carbonyl}(1-methylcyclopropyl)(1-methylcyclopropyl)sulfonamide 19l an extremely potent (K(i)=0.20 nM, EC(50)=3.7 nM), selective, and orally bioavailable dipeptide NS3/4A protease inhibitor, which has features attractive for further preclinical development.     

No Evidence for Adaptive Micro-Evolution to a Decrease in Phosphorus-Loading of a Daphnia Population Inhabiting A Pre-Alpine Lake

Many polluted lakes in Europe are being restored and phosphorus concentrations have dropped dramatically in these lakes. We studied the genetic structure of Daphnia galeata over the past 30 years in Lake Greifensee, Switzerland, a period during which the phosphorus concentration in the lake reduced dramatically. Distinct genotypes of D. galeata were hatched from diapausing eggs extracted from six different time horizons in dated sediments. We compared juvenile growth, size and egg production of D. galeata reared on high-P and low-P algae to investigate whether Daphnia have evolved to grow better on phosphorus-limited algae. Our results indicate that life histories of D. galeata differed significantly between both food types. We also found significant clone effects for size and egg number. But we found no significant interaction between the depth from which the clones were selected and food quality. This means that we found no evidence for adaptive micro-evolution in response to P reduction in the lake. We discuss our results in relation to other studies that found evidence for adaptive micro-evolution in comparable time frames.