Resolving pathways of interaction of mipafox and a sarin analog with human acetylcholinesterase by kinetics, mass spectrometry and molecular modeling approaches

The hydroxyl oxygen of the catalytic triad serine in the active center of serine hydrolase acetylcholinesterase (AChE) attacks organophosphorus compounds (OPs) at the phosphorus atom to displace the primary leaving group and to form a covalent bond. Inhibited AChE can be reactivated by cleavage of the Ser-phosphorus bond either spontaneously or through a reaction with nucleophilic agents, such as oximes. At the same time, the inhibited AChE adduct can lose part of the molecule by progressive dealkylation over time in a process called aging. Reactivation of the aged enzyme has not yet been demonstrated. Here, our goal was to study oxime reactivation and aging reactions of human AChE inhibited by mipafox or a sarin analog (Flu-MPs, fluorescent methylphosphonate). Progressive reactivation was observed after Flu-MPs inhibition using oxime 2-PAM. However, no reactivation was observed after mipafox inhibition with 2-PAM or the more potent oximes used. A peptide fingerprinted mass spectrometry (MS) method, which clearly distinguished the peptide with the active serine (active center peptide, ACP) of the human AChE adducted with OPs, was developed by MALDI-TOF and MALDI-TOF/TOF. The ACP was detected with a diethyl-phosphorylated adduct after paraoxon inhibition, and with an isopropylmethyl-phosphonylated and a methyl-phosphonylated adduct after Flu-MPs inhibition and subsequent aging. Nevertheless, nonaged nonreactivated complexes were seen after mipafox inhibition and incubation with oximes, where MS data showed an ACP with an NN diisopropyl phosphoryl adduct. The kinetic experiments showed no reactivation of activity. The computational molecular model analysis of the mipafox-inhibited hAChE plots of energy versus distance between the atoms separated by dealkylation showed a high energy demand, thus little aging probability. However, with Flu-MPs and DFP, where aging was observed in our MS data and in previously published crystal structures, the energy demand calculated in modeling was lower and, consequently, aging appeared as a more likely reaction. We document here direct evidence for a phosphorylated hAChE refractory to oxime reactivation, although we observed no aging.

The search for plants with anticancer activity: pitfalls at the early stages

Inhibition assays on tumour cells in vitro are commonly used to confirm the activity of extracts, fractions and compounds from plants reported to be antitumoural. The majority of assays report the IC50 (50% inhibitory concentration), whereas others distinguish between inhibition of cell proliferation (cytostasis) and cell death (cytotoxicity). Here, we offer some suggestions as to the different types of assay, the cell lines that may be used, control cells and drugs, as well as the interpretation of the results. Using both theoretical considerations and experimental data, we specifically question the frequent overinterpretation of reported results regarding the selectivity for cancer cells of the plant extract or compound under study, concluding that this "selectivity" is due to a quantitative difference in cell proliferation rates, rather than a qualitative difference between normal and tumour cells. Inhibition assays will always represent one of the first steps in the discovery of clinically valuable new drugs, but these assays do not allow us to conclude that we have found the "magic bullet".

Endovascular repair of acute uncomplicated aortic type B dissection promotes aortic remodelling: 1 year results of the ADSORB trial

OBJECTIVES

Uncomplicated acute type B aortic dissection (AD) treated conservatively has a 10% 30-day mortality and up to 25% need intervention within 4 years. In complicated AD, stent grafts have been encouraging. The aim of the present prospective randomised trial was to compare best medical treatment (BMT) with BMT and Gore TAG stent graft in patients with uncomplicated AD. The primary endpoint was a combination of incomplete/no false lumen thrombosis, aortic dilatation, or aortic rupture at 1 year.

METHODS

The AD history had to be less than 14 days, and exclusion criteria were rupture, impending rupture, malperfusion. Of the 61 patients randomised, 80% were DeBakey type IIIB.

RESULTS

Thirty-one patients were randomised to the BMT group and 30 to the BMT+TAG group. Mean age was 63 years for both groups. The left subclavian artery was completely covered in 47% and in part in 17% of the cases. During the first 30 days, no deaths occurred in either group, but there were three crossovers from the BMT to the BMT+TAG group, all due to progression of disease within 1 week. There were two withdrawals from the BMT+TAG group. At the 1-year follow up there had been another two failures in the BMT group: one malperfusion and one aneurysm formation (p = .056 for all). One death occurred in the BMT+TAG group. For the overall endpoint BMT+TAG was significantly different from BMT only (p < .001). Incomplete false lumen thrombosis, was found in 13 (43%) of the TAG+BMT group and 30 (97%) of the BMT group (p < .001). The false lumen reduced in size in the BMT+TAG group (p < .001) whereas in the BMT group it increased. The true lumen increased in the BMT+TAG (p < .001) whereas in the BMT group it remained unchanged. The overall transverse diameter was the same at the beginning and after 1 year in the BMT group (42.1 mm), but in the BMT+TAG it decreased (38.8 mm; p = .062).

CONCLUSIONS

Uncomplicated AD can be safely treated with the Gore TAG device. Remodelling with thrombosis of the false lumen and reduction of its diameter is induced by the stent graft, but long term results are needed.

Extracorporeal photopheresis for treatment of adults and children with acute GVHD: UK consensus statement and review of published literature

Extracorporeal photopheresis (ECP) has been used for over 20 years to treat acute GVHD (aGVHD) and chronic GVHD. Evidence on the efficacy of response in aGVHD has continued to accrue and data suggest that there is a good response and prolonged survival in both children and adults with grade II-IV aGVHD. Unlike chronic GVHD where treatment schedules are typically one or two times monthly for 12-18 months, patients with aGVHD respond rapidly to an intense weekly treatment schedule for 8 weeks, typically allowing steroids to be discontinued without flare-ups of aGVHD. Maintenance ECP therapy is generally not required. Many centres across Europe and United States treat aGVHD with ECP as second-line therapy and responses are excellent in a subset of patients. Unlike other second-line therapies, ECP is not immunosuppressive and has no reported drug interactions. Importantly, ECP does not have a negative impact on the graft-versus-malignancy effect of the transplant. This statement aims to select those patients most likely to respond to treatment and summarises treatment and monitoring schedules for the management of aGVHD in adult and paediatric patients to ensure the correct patients are treated with the optimal protocol for efficacy.

Changes in mental state associated with prison environments: a systematic review

OBJECTIVE

To develop an understanding of the stability of mental health during imprisonment through review of existing research evidence relating physical prison environment to mental state changes in prisoners.

METHOD

A systematic literature search was conducted looking at changes in mental state and how this related to various aspects of imprisonment and the prison environment.

RESULTS

Fifteen longitudinal studies were found, and from these, three broad themes were delineated: being imprisoned and aspects of the prison regime; stage of imprisonment and duration of sentence; and social density. Reception into prison results in higher levels of psychiatric symptoms that seem to improve over time; otherwise, duration of imprisonment appears to have no significant impact on mental health. Regardless of social density, larger prisons are associated with poorer mental state, as are extremes of social density.

CONCLUSION

There are large gaps in the literature relating prison environments to changes in mental state; in particular, high-quality longitudinal studies are needed. Existing research suggests that although entry to prison may be associated with deterioration in mental state, it tends to improve with time. Furthermore, overcrowding, ever more likely as prison populations rise, is likely to place a particular burden on mental health services.

Parents' preferences for return of results in pediatric genomic research

BACKGROUND

The aim of this study was to ascertain parental preferences for the return of genetic research results on themselves and their children and their choices for genetic research results to receive.

METHODS

A mail survey was sent to 6,874 families seen at Boston Children's Hospital. The survey included questions assessing the respondents' preferences regarding the types of result they wanted to receive on themselves and their children.

RESULTS

Most of the 1,060 respondents 'probably' or 'definitely' wanted to receive genetic research results about themselves (84.6%) and their children (88.0%). Among those who wanted to receive results, 83.4% wanted to receive all research results for themselves and 87.8% for their children. When questions about specific types of research results were combined into a composite measure, fewer respondents chose to receive all results for themselves (53.5%) and for their children (56.9%).

CONCLUSION

Although most parents report a desire to receive all research results on a general question, almost half chose to receive only a subset of research results when presented with specific types of research results. Our findings suggest that participants might not understand the implications of their choice of individual research results to receive unless faced with specific types of results.

Children with nephrotic syndrome have greater bone area but similar volumetric bone mineral density to healthy controls

BACKGROUND

Glucocorticoid use has been associated with an increased fracture risk and reduced bone mineral density (BMD), particularly in the trabecular compartment. However the contribution of the underlying inflammatory disease process to these outcomes is poorly understood. Childhood nephrotic syndrome (NS) typically follows a relapsing-remitting course often requiring recurrent courses of glucocorticoids, but with low systemic inflammation during remission. NS therefore represents a useful clinical model to investigate the effects of glucocorticoids on BMD and bone geometry in childhood.

METHODS

Children with NS were compared to age and sex matched healthy controls. Body composition and areal BMD (whole body, lumbar spine and hip) were assessed by DXA. Peripheral quantitative computed tomography (pQCT) scans were obtained at metaphyseal (4%) and diaphyseal (66%) sites of the tibia to determine volumetric BMD and bone cross-sectional geometry. Lifetime cumulative glucocorticoid exposure was calculated from medical records.

RESULTS

29 children with NS (55% male, age 10.7±3.1years) were compared to 29 healthy controls (55% male, age 11.0±3.0years). The children with NS were of similar height SDS to controls (p=0.28), but were heavier (0.65±1.28SDS vs -0.04±0.89SDS, p=0.022) and had greater body fat percentage SDS (0.31±1.01 vs -0.52±1.10, p=0.008). Tibial trabecular and cortical vBMD were similar between the two groups but bone cross-sectional area (CSA) was significantly greater in children with NS at both the metaphysis (954±234mm(2) vs 817±197mm(2), p=0.002) and diaphysis (534.9±162.7mm(2) vs 463.2±155.5mm(2), p=0.014). Endosteal and periosteal circumferences were greater in children with NS than controls (both p<0.01), resulting in reduced cortical thickness (2.4±0.7mm vs 2.8±0.7mm, p=0.018), but similar cortical CSA (p=0.22). The differences in cortical geometry were not statistically significant when weight was included as a confounding factor. There were no associations between cumulative steroid exposure, duration of NS or number of relapses and any bone parameter.

CONCLUSIONS

Tibial bone CSA is increased in children with NS. We speculate that this is a compensatory response to increased body weight. Defects in trabecular BMD were not identified in this cohort of children with NS.

Anti-inflammatory and antitumoural effects of Uncaria guianensis bark

ETHNOPHARMACOLOGICAL RELEVANCE

Uncaria guianensis (Aublet) Gmell (Rubiaceae) is a medicinal plant from the jungles of South and Central America, used to treat cancer, arthritis, diabetes, and inflammation. Evaluate the anti-inflammatory and anti-tumor effects of Uncaria guianensis preparations.

MATERIALS AND METHODS

Bio-guided fractionation of a hydroethanolic extract of Uncaria guianensis was performed, evaluating the fractions and subfractions for their effect on inflammatory mediators, tumour necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and prostaglandin E2 (PGE2) by ELISA and nitric oxide (NO) by the Griess reaction in cultured supernatant from RAW 264.7 macrophages stimulated with lipopolysaccharide (LPS). The expression of cyclooxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS) and inhibitor of κB (IκB) were investigated in RAW 264.7 macrophages by flow cytometry. The activity of NF-κB in HeLa cells transfected with a luciferase reporter system was determined. The effect of Uncaria guianensis on the inflammatory response in vivo was assessed in BALB/c mice stimulated with LPS, on rat paw oedema induced by carrageenan, and on tumour growth and lung metastasis in BALB/c mice inoculated with 4T1 mammary tumour cells. Immune cell infiltrates and inflammatory mediators were evaluated in the tumour by immunohistochemistry.

RESULTS

Sub-fraction Ug AIV inhibited, to varying degrees, NO, TNF-α, IL-6 and PGE2 production by macrophages in vitro (30 μg/ml) and in the serum of LPS-challenged mice (5 mg/kg). Macrophage expression of Cox-2 was inhibited (35%), IκB degradation was completely inhibited and NF-κB activation was inhibited (70%) by Ug AIV at 30 μg/ml. Ug AIV decreased paw oedema by 86% (5 mg/kg) and serum NO and TNF-α by 45% and 65% respectively. Ug AIV reduced 4T1 mammary tumour growth by 91% on day 33 post-inoculation as well as the levels of serum NO, IL-6 and TNF-α in the same animals. Ug AIV decreased the number of tumour-infiltrating T lymphocytes, macrophages and neutrophils as well as the number of cells positive for COX-2, iNOS, IL-6, TNF-α and p65.

CONCLUSIONS

As Ug AIV was not cytotoxic for tumour cells or macrophages, its anti-tumour effect may be due to a reduction in pro-tumoural inflammatory processes in the tumour microenvironment, possibly mediated through NF-κB.

A naturalistic evaluation and audit database of agomelatine: clinical outcome at 12 weeks

OBJECTIVE

To determine the effectiveness of agomelatine in routine clinical practice and explore factors associated with response and continuation.

METHOD

Consecutive patients prescribed agomelatine in participating psychiatric services were included. Patient demographic and outcome data were collected at treatment initiation and then at weeks 4, 8 and 12. Outcomes were analysed with respect to clinical and demographic factors.

RESULTS

A total of 110 patients from nine NHS trusts were followed through 12 weeks of treatment. Agomelatine was largely used in difficult-to-treat or refractory patients: 83 (75%) had failed to respond to, or relapsed on, prior antidepressants. There were high rates of physical (54.5%) and psychiatric (50.0%) comorbidity. At 12 weeks of treatment, 68 (62%) continued agomelatine treatment. Overall, 69 subjects (62.7%) improved by at least one point of the Clinical Global Impression (severity) scale. Of 42 who discontinued, 23 (56%) discontinued because of lack of efficacy and 10 (24%) due to an adverse event. Of all variables examined, only a history of more than five episodes of depression significantly predicted discontinuation of treatment (OR continuation - 0.36, 95% CI 0.14, 0.95).

CONCLUSION

Agomelatine was effective and generally well tolerated in a cohort of difficult-to-treat patients in clinical practice.

Interactions between an injected polydnavirus and per os baculovirus in gypsy moth larvae

Larval gypsy moths, Lymantria dispar (Lepidoptera:Lymantriidae) were co-infected with the L. dispar nucleopolyhedrovirus (LdMNPV) and the Cotesia melanoscela (Hymenoptera:Braconidae) polydnavirus (CmeBV). CmeBV was given along with a parasitoid egg and calyx products in a stinging event, or in the form of an injection of calyx-derived extract. LdMNPV was delivered per os, integrated into artificial diet. Mortality from all sources was recorded over the subsequent three-week period. Neither parasitism nor injections of purified CmeBV with toxin had any effect on the amount of mortality caused by concurrent challenges with LdMNPV.

A randomized controlled double-blind investigation of the effects of vitamin D dietary supplementation in subjects with atopic dermatitis

BACKGROUND

Subjects with atopic dermatitis (AD) have defects in antimicrobial peptide (AMP) production possibly contributing to an increased risk of infections. In laboratory models, vitamin D can alter innate immunity by increasing AMP production.

OBJECTIVE

To determine if AD severity correlates with baseline vitamin D levels, and to test whether supplementation with oral vitamin D alters AMP production in AD skin.

METHODS

This was a multi-centre, placebo-controlled, double-blind study in 30 subjects with AD, 30 non-atopic subjects, and 16 subjects with psoriasis. Subjects were randomized to receive either 4000 IU of cholecalciferol or placebo for 21 days. At baseline and day 21, levels of 25-hydroxyvitamin D (25OHD), cathelicidin, HBD-3, IL-13, and Eczema Area and Severity Index (EASI) and Rajka-Langeland scores were obtained.

RESULTS

At baseline, 20% of AD subjects had serum 25OHD below 20 ng/mL. Low serum 25OHD correlated with increased Fitzpatrick Skin Type and elevated BMI, but not AD severity. After 21 days of oral cholecalciferol, mean serum 25OHD increased, but there was no significant change in skin cathelicidin, HBD-3, IL-13 or EASI scores.

CONCLUSIONS

This study illustrated that darker skin types and elevated BMI are important risk factors for vitamin D deficiency in subjects with AD, and highlighted the possibility that seasonality and locale may be potent contributors to cathelicidin induction through their effect on steady state 25OHD levels. Given the molecular links between vitamin D and immune function, further study of vitamin D supplementation in subjects with AD is warranted.

Future imaging techniques in aortic pathologies and clinical implications

Future imaging techniques in aortic pathology will be used to detect early subclinical pathological changes and to identify patients who would benefit from early surgical intervention. Current imaging for aortic pathology is mainly computed tomography (CT). This modality produces static images which are used as the basis to decide which patients require intervention. Subclinical disease can be detected experimentally by novel magnetic resonance (MR) techniques such as molecular imaging: measurement of the amount of elastin in the aortic wall has the potential to identify patients with low levels of elastin at risk of aortic dilatation. These patients could then be monitored in a more intensive aneurysm surveillance programme. Endothelial dysfunction can also be detected experimentally by MR techniques. Measurement of endothelial permeability will be used to tailor preventative medical treatment to individual patients. Aortic diameter is the main indication for treatment in both aortic aneurysms and chronic aortic dissection but may be prone to error. False lumen thrombosis detected on first-pass imaging is used as an outcome measure in randomized controlled trials. Blood pool contrast agent imaging is flow independent and is not subject to the significant error associated with current imaging methods. Four-dimensional phase contrast magnetic resonance (4D PC-MR) imaging can quantify flow in both the true and false lumens of aortic dissection. The amount and pattern of flow in the false lumen is related to the rate of aortic expansion. 4D PC-MR can demonstrate entry tears between the true and false lumens and this information can be used to guide endovascular treatment. Hybrid imaging techniques such as positron emission tomography (PET) combined with CT (PET-CT) can give information about the degree of inflammation in the aortic wall, and preliminary studies have shown that a positive scan can predict patients with dissection who are likely to have a poor outcome. These new techniques combine anatomical and functional data in a single acquisition. The richness of the data allows a greater understanding of the pathophysiology in each individual patient which will result in improved clinical outcomes.