1,126 research outputs found
Ultrafast photodissociation dynamics of pyrazole, imidazole and their deuterated derivatives using ab initio multiple cloning
We present results obtained using the ab initio multiple cloning (AIMC) method to simulate fully quantum dynamics for imidazole and its structural isomer pyrazole along with their selectively deuterated species. We simulate the ultrafast dissociation of the N-H/D bond for these molecules along the repulsive 1ÏÏ* state which agrees well with previous experimental results. Our results give evidence for a two-stage dissociation of the N-H/D bond on the sub-50 fs regime for imidazole, pyrazole and their selectively deuterated species, and give evidence for the importance of the repulsive 1ÏÏ* state along the N-H/D bond coordinate for the relaxation of both imidazole and pyrazole. The ability of these calculations to reproduce experimental results lends confidence that larger complex systems could be explored with predictive capabilities with the AIMC method. These results also confirm the ability of the AIMC method to add detailed insights into which experiments are blind
Identification and characterisation of anti - Pseudomonas aeruginosa proteins in mucus of the brown garden snail, Cornu aspersum
Background Novel antimicrobial treatments are urgently needed. Previous work has shown that the mucus of the brown garden snail (Cornu aspersum) has antimicrobial properties, in particular against type culture collection strains of Pseudomonas aeruginosa. We hypothesised that it would also be effective against clinical isolates of the bacterium and that investigation of fractions of the mucus would identify one or more proteins with anti-pseudomonal properties, which could be further characterised. Materials and methods: Mucus was extracted from snails collected from the wild. Antimicrobial activity against laboratory and clinical isolates of Ps. aeruginosa was determined in disc diffusion assays. Mucus was purified using size exclusion chromatography and fractions containing anti-pseudomonal activity identified. Mass spectroscopy and high performance liquid chromatography analysis of these fractions yielded partial peptide sequences. These were used to interrogate an RNA transcriptome generated from whole snails. Results: Mucus from C. aspersum inhibited growth of type collection strains and clinical isolates of Ps. aeruginosa. Four novel C. aspersum proteins were identified; at least three are likely to have antimicrobial properties. The most interesting is a 37.4 kDa protein whilst smaller proteins, one 17.5 kDa and one 18.6 kDa also appear to have activity against Ps. aeruginosa. Conclusions: The study has identified novel proteins with antimicrobial properties which could be used to develop treatments for use in human medicine. Key words: antimicrobial; transcriptome; lectin; mucus; Cornu aspersum, Pseudomonas aeruginosa, transcriptom
A phase II study of weekly neoadjuvant chemotherapy followed by radical chemoradiation for locally advanced cervical cancer
Background:
We investigated the feasibility of dose-dense neoadjuvant chemotherapy (NACT) with paclitaxel and carboplatin before radical chemoradiation (CRT) and assessed the response rate to such a regimen.
Methods:
CxII is a single-arm phase II trial of 46 patients, with locally advanced cervical cancer (stage Ib2-IVa). Patients received dose-dense carboplatin (AUC2) and paclitaxel (80âmgâmâ2) weekly for six cycles followed by CRT (40âmgâmâ2 of weekly cisplatin, 50.4âGy, 28 fractions plus brachytherapy). The primary end point was response rate 12 weeks post-CRT.
Results:
Baseline characteristics were: median age at diagnosis 43 years; 72% squamous, 22% adenocarcinoma and 7% adenosquamous histologies; FIGO stage IB2 (11%), II (50%), III (33%), IV (7%). Complete or partial response rate was 70% (95% CI: 54â82) post-NACT and 85% (95% CI: 71â94) post-CRT. The median follow-up was 39.1 months. Overall and progression-free survivals at 3 years were 67% (95% CI: 51â79) and 68% (95% CI: 51â79), respectively. Grade 3/4 toxicities were 20% during NACT (11% haematological, 9% non-haematological) and 52% during CRT (haematological: 41%, non-haematological: 22%).
Conclusion:
A good response rate is achieved by dose-dense weekly NACT with carboplatin and paclitaxel followed by radical CRT. This treatment regimen is feasible as evidenced by the acceptable toxicity of NACT and by the high compliance to radiotherapy (98%)
Measuring the impact of trigeminal neuralgia pain: the Penn Facial Pain Scale-Revised
BACKGROUND AND OBJECTIVE: The Penn Facial Pain Scale (Penn-FPS) was originally developed as a supplemental module to the Brief Pain Inventory Pain Interference Index (BPI-PII) in order to fully assess the impact of trigeminal neuralgia (TN) pain on patientsâ health-related quality of life (HRQoL). The current objective is to create and establish the content validity of a new stand-alone version of the measure, the Penn-FPS-Revised (Penn-FPS-R).
METHODS: Twenty participants (15 USA and 5 UK) with confirmed TN engaged in concept elicitation and cognitive debriefing interviews. These semi-structured interviews allowed participants to spontaneously describe the ways in which TN impacts on HRQoL and report on the extent to which the Penn-FPS and BPI-PII measure concepts are most relevant to them. Participants were also asked to report on the suitability of the instructions, recall period, and response options.
RESULTS: Concept elicitation revealed nine themes involving TN restrictions on daily activities and HRQoL, including: âtalking,â âself-care,â âeating,â âeating hard foods/chewing foods,â âdaily activities,â âactivities with temperature change,â âtouching,â âmood,â and ârelationships.â Cognitive debriefing confirmed that all of the Penn-FPS concepts and some of the BPI-PII concepts (âmood,â âgeneral activities,â and ârelations with othersâ) were relevant, although some items required edits to better capture individualsâ experiences. The impact of temperature and/or weather on activities was also identified as an important concept that is not captured by the Penn-FPS or BPI-PII. Participants confirmed the acceptability of recall period, instructions, and response options. Results from the interviews were applied to create the Penn-FPS-R, a new brief outcome measure that assesses the impacts of TN most important to patients.
CONCLUSION:The Penn-FPS-R is a new 12-item HRQoL outcome measure with content validity that can be used to assess and monitor the impact of TN treatment interventions in both clinical practice and research
Ultrafast photodissociation dynamics of 2-ethylpyrrole: adding insight to experiment with ab initio multiple cloning
The ultrafast photodissociation dynamics of 2-ethylpyrrole (2-EP) is simulated in a fully quantum manner on the S1 and S2 ÏÏ* states by the ab initio multiple cloning (AIMC) method. AIMC treats electrons with accurate electronic structure methods âon the flyâ, and nuclear dynamics with wavefunction propagation via a basis set of Ehrenfest trajectory guided Gaussian wavepackets. Total kinetic energy release (TKER) spectra are produced, as well as velocity map images and NâH dissociation times. These are compared to results from time-resolved velocity map imaging studies, and the AIMC method is able to provide quantitative reproduction of experimental data, including dissociation times of 50â80 fs. Novel insight into the dissociation mechanism is then obtained, with the experimentally obtained time constant shown to be composed of two components. Firstly, there is a contribution in <50 fs from 2-EP molecules that have sufficient energy in the NâH stretch coordinate to dissociate almost immediately over the barrier, and this is followed by a second slower contribution from 2-EP molecules that must sample the potential energy surface before finding a way around the barrier to dissociate. This two component mechanism is not observed experimentally due to the temporal widths of the laser pulses obscuring the dynamics in the <50 fs window, and is shown for the first time via theory. Calculations are also performed on selectively deuterated 2-EP, demonstrating that AIMC is able to produce a kinetic isotope effect for the dissociation time constant, and correctly predict a shift to lower energy in the TKER spectrum. The S2 ÏÏ* state is also shown to be unstable with respect to the S1 ÏÏ* state, with the NâH dissociation proceeding along S1 when initially excited to S2. This work demonstrates that the combination of state of the art theory and experiments can provide unprecedented novel insight into the NâH dissociation mechanism, with the tantalising prospect of providing insight into more general heteroatom hydride bond dissociation
Prediction of melanoma metastasis by the Shields index based on lymphatic vessel density
<p>Abstract</p> <p>Background</p> <p>Melanoma usually presents as an initial skin lesion without evidence of metastasis. A significant proportion of patients develop subsequent local, regional or distant metastasis, sometimes many years after the initial lesion was removed. The current most effective staging method to identify early regional metastasis is sentinel lymph node biopsy (SLNB), which is invasive, not without morbidity and, while improving staging, may not improve overall survival. Lymphatic density, Breslow's thickness and the presence or absence of lymphatic invasion combined has been proposed to be a prognostic index of metastasis, by Shields et al in a patient group.</p> <p>Methods</p> <p>Here we undertook a retrospective analysis of 102 malignant melanomas from patients with more than five years follow-up to evaluate the Shields' index and compare with existing indicators.</p> <p>Results</p> <p>The Shields' index accurately predicted outcome in 90% of patients with metastases and 84% without metastases. For these, the Shields index was more predictive than thickness or lymphatic density. Alternate lymphatic measurement (hot spot analysis) was also effective when combined into the Shields index in a cohort of 24 patients.</p> <p>Conclusions</p> <p>These results show the Shields index, a non-invasive analysis based on immunohistochemistry of lymphatics surrounding primary lesions that can accurately predict outcome, is a simple, useful prognostic tool in malignant melanoma.</p
Accelerated partner therapy (APT) partner notification for people with Chlamydia trachomatis: protocol for the Limiting Undetected Sexually Transmitted infections to RedUce Morbidity (LUSTRUM) APT cross-over cluster randomised controlled trial
INTRODUCTION: Partner notification (PN) is a process aiming to identify, test and treat the sex partners of people (index patients) with sexually transmitted infections (STIs). Accelerated partner therapy (APT) is a PN method whereby healthcare professionals assess sex partners, by telephone consultation, before giving the index patient antibiotics and STI self-sampling kits to deliver to their sex partner(s). The Limiting Undetected Sexually Transmitted infections to RedUce Morbidity programme aims to determine the effectiveness of APT in heterosexual women and men with chlamydia and determine whether APT could affect Chlamydia trachomatis transmission at population level. METHODS AND ANALYSIS: This protocol describes a cross-over cluster randomised controlled trial of APT, offered as an additional PN method, compared with standard PN. The trial is accompanied by an economic evaluation, transmission dynamic modelling and a qualitative process evaluation involving patients, partners and healthcare professionals. Clusters are 17 sexual health clinics in areas of England and Scotland with contrasting patient demographics. We will recruit 5440 heterosexual women and men with chlamydia, aged â„16 years.The primary outcome is the proportion of index patients testing positive for C. trachomatis 12-16 weeks after the PN consultation. Secondary outcomes include: proportion of sex partners treated; cost effectiveness; model-predicted chlamydia prevalence; experiences of APT.The primary outcome analysis will be by intention-to-treat, fitting random effects logistic regression models that account for clustering of index patients within clinics and trial periods. The transmission dynamic model will be used to predict change in chlamydia prevalence following APT. The economic evaluation will use mathematical modelling outputs, taking a health service perspective. Qualitative data will be analysed using interpretative phenomenological analysis and framework analysis. ETHICS AND DISSEMINATION: This protocol received ethical approval from London-Chelsea Research Ethics Committee (18/LO/0773). Findings will be published with open access licences. TRIAL REGISTRATION NUMBER: ISRCTN15996256
Sex Promotes Spatial and Dietary Segregation in a Migratory Shorebird during the Non-Breeding Season
Several expressions of sexual segregation have been described in animals, especially in those exhibiting conspicuous dimorphism. Outside the breeding season, segregation has been mostly attributed to size or age-mediated dominance or to trophic niche divergence. Regardless of the recognized implications for population dynamics, the ecological causes and consequences of sexual segregation are still poorly understood. We investigate the foraging habits of a shorebird showing reversed sexual dimorphism, the black-tailed godwit Limosa limosa, during the winter season, and found extensive segregation between sexes in spatial distribution, microhabitat use and dietary composition. Males and females exhibited high site-fidelity but differed in their distributions at estuary-scale. Male godwits (shorter-billed) foraged more frequently in exposed mudflats than in patches with higher water levels, and consumed more bivalves and gastropods and fewer polychaetes than females. Females tended to be more frequently involved and to win more aggressive interactions than males. However, the number of aggressions recorded was low, suggesting that sexual dominance plays a lesser role in segregation, although its importance cannot be ruled out. Dimorphism in the feeding apparatus has been used to explain sex differences in foraging ecology and behaviour of many avian species, but few studies confirmed that morphologic characteristics drive individual differences within each sex. We found a relationship between resource use and bill size when pooling data from males and females. However, this relationship did not hold for either sex separately, suggesting that differences in foraging habits of godwits are primarily a function of sex, rather than bill size. Hence, the exact mechanisms through which this segregation operates are still unknown. The recorded differences in spatial distribution and resource use might expose male and female to distinct threats, thus affecting population dynamics through differential mortality. Therefore, population models and effective conservation strategies should increasingly take sex-specific requirements into consideration
The influence of the Cyclin D1 870 G>A polymorphism as an endometrial cancer risk factor
<p>Abstract</p> <p>Background</p> <p>Cyclin D1 is integral for the G1 to S phase of the cell cycle as it regulates cellular proliferation. A polymorphism in cyclin D1, 870 G>A, causes overexpression and supports uncontrollable cellular growth. This polymorphism has been associated with an increased risk of developing many cancers, including endometrial cancer.</p> <p>Methods</p> <p>The 870 G>A polymorphisms (rs605965) in the cyclin D1 gene was genotyped in an Australian endometrial cancer case-control population including 191 cases and 291 controls using real-time PCR analysis. Genotype analysis was performed using chi-squared (Ï<sup>2</sup>) statistics and odds ratios were calculated using unconditional logistic regression, adjusting for potential endometrial cancer risk factors.</p> <p>Results</p> <p>Women homozygous for the variant cyclin D1 870 AA genotype showed a trend for an increased risk of developing endometrial cancer compared to those with the wild-type GG genotype, however this result was not statistically significant (OR 1.692 95% CI (0.939â3.049), p = 0.080). Moreover, the 870 G>A polymorphism was significantly associated with family history of colorectal cancer. Endometrial cancer patients with the homozygous variant AA genotype had a higher frequency of family members with colorectal cancer in comparison to endometrial cancer patients with the GG and combination of GG and GA genotypes (GG versus AA; OR 2.951, 95% CI (1.026â8.491), p = 0.045, and GG+GA versus AA; OR 2.265, 95% CI (1.048â4.894), p = 0.038, respectively).</p> <p>Conclusion</p> <p>These results suggest that the cyclin D1 870 G>A polymorphism is possibly involved in the development of endometrial cancer. A more complex relationship was observed between this polymorphism and familial colorectal cancer.</p
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