Two bridge-particle-mediated RET between chiral molecules

The problem of resonance energy transfer between a pair of chiral molecules mediated by two electrically polarizable bridging particles is solved using molecular QED theory. In this framework a single virtual photon propagates between any two-coupled entities and is responsible for the conveyance of excitation energy from emitter to absorber. Electric dipole and quadrupole, and magnetic dipole couplings linear in the Maxwell fields are employed for donor and acceptor, while each mediator scatters two virtual photons and responds quadratically to the electric displacement field via its electric dipole polarizability. This enables fourth-order diagrammatic perturbation theory to be used to compute the probability amplitude for the process. Individual multipole moment contributions to the Fermi golden rule rate are then extracted for oriented and isotropic systems. Discriminatory transfer rates arise when either the donor or the acceptor are electric-magnetic dipole and the other has a pure multipole moment, or when both are chiral, with mixed electric dipole-quadrupole contributions vanishing in the fluid phase. The bridge-mediated transfer rate is found to be a maximum for a collinear geometry. Moreover, a multi-level model of the mediator is necessary for energy migration. Asymptotically limiting rates for arbitrary and collinear geometries are also obtained for one centre purely electric dipolar and the other purely quadrupolar, or both donor and absorber purely quadrupolar. Understanding is gained of radiationless and radiative transfer mechanisms between chiral moieties in a dielectric medium.

POS1083 INCREASED INTESTINAL PERMEABILITY IN PATIENTS WITH PSORIATIC ARTHRITIS CLASSIFIED AS TREATMENT FAILURES DURING THE 26-WEEK FLORA TRIAL

Background

Changes in the integrity of the intestinal wall may be implicated in the gut-joint axis of inflammatory arthritis.1 Yet, the gut barrier is only poorly evaluated in psoriatic arthritis (PsA).2

Objectives

In this exploratory study, we evaluated intestinal permeability before and 26 weeks after one faecal microbiota transplantation (FMT) or sham intervention in adults with PsA.

Methods

We have previously reported the clinical results of a 26-week, double-blind, parallel-group, 1:1 randomised, sham-controlled, superiority trial of gastroscopic-guided FMT as an add-on treatment to methotrexate in 31 adults with active peripheral PsA (FLORA trial, NCT03058900).3 The primary efficacy endpoint was the proportion of participants who experienced treatment failure through 26 weeks, defined as need for more than one intra-articular glucocorticoid injection and/or anti-TNFα inhibition. We encouraged patients not to take nonsteroidal anti-inflammatory drugs during the trial. The FMT material was obtained from one of four healthy blood donors. As part of the trial, we performed a lactulose and mannitol test (L:M test) at baseline (n=31) and at the final 26-week visit (n=26) to assess the permeability of the intestinal wall (higher L:M ratios indicate higher permeability). After an overnight fasting, patients provided a urine sample before ingesting 10 g of lactulose and 5 g of D-mannitol. Samples were collected after 3 hours and stored at −80°C until analysis. No food or drinking (except for water) was allowed during the test. We measured the lactulose-to-mannitol ratio in the urine samples using a Waters Acquity UPLC system coupled to a high-resolution mass spectrometer Waters Xevo G2 QToF (Waters Corp., Milford, MA, USA). MassLynx software (Waters Corporation) was used for data acquisition and visual inspection. We used StataSE-64 to perform the Wilcoxon rank sum and the matched-pairs signed-rank test. Data is presented as median and range. The level of significance was set to 0.05.

Results

At baseline, no significant difference was observed in the L:M ratio between donors (n=4) and patients (n=31) (0.0065 [0–0.063] vs 0.014 [0–0.28]; p=0.50). The L:M ratio increased from baseline to week 26 in both the FMT (0.0020 [-0.27 – 0.32] and the sham group (0.0046 [-0.012 – 0.088]), but only in the sham group differed the baseline L:M ratio significantly from the one measured at week 26 (p=0.92 [FMT] and p=0.032 [sham]). The patients who were classified as treatment failures during the trial (n=7) had a significantly higher L:M ratio at week 26 compared to the patients who were non-failures (n=19) (0.027 [0.017 – 0.33]) vs 0.012 [0 – 0.064], p=0.01), please see Figure 1.

Figure 1.

L:M ratios at week 26 in treatment failures (n=7) and non-failures (n=19), respectively. Higher L:M ratios indicate higher intestinal permeability.

Conclusion

In the FLORA trial, intestinal permeability evaluated by the L:M test did not differ significantly between donors and patients at baseline. Whether the higher intestinal permeability observed in patients classified as treatment failures compared to non-failures at week 26 can be attributed to differences in disease activity and/or the instigation of additional immunosuppression in the failure group during the trial needs further investigation.

References

[1]Gracey E, Vereecke L, McGovern D, et al. Revisiting the gut-joint axis: links between gut inflammation and spondyloarthritis. Nat Rev Rheumatol. 2020;16(8):415-433.

[2]Hecquet S, Totoson P, Martin H, et al. Intestinal permeability in spondyloarthritis and rheumatoid arthritis: A systematic review of the literature. Semin Arthritis Rheum. 2021;51(4):712-718.

[3]Kragsnaes MS, Kjeldsen J, Horn HC, et al. Safety and efficacy of faecal microbiota transplantation for active peripheral psoriatic arthritis: an exploratory randomised placebo-controlled trial. Ann Rheum Dis. 2021;80(9):1158-1167.

Disclosure of Interests

None declared

Discriminatory Resonance Energy Transfer Mediated by a Third Molecule

Relay of resonant excitation energy between two chiral molecules by an inert third particle is studied using molecular quantum electrodynamics theory. A single virtual photon propagates between each interacting pair. Fourth-order diagrammatic time-dependent perturbation theory is employed to compute the matrix element. Rate terms dependent upon the chirality of the donor and acceptor species are extracted using the Fermi golden rule. Interestingly, the mediated rate is discriminatory. For freely tumbling particles it exhibits an inverse-square dependence on each interparticle separation distance, indicating a purely radiative exchange mechanism. Furthermore, the isotropic rate is found to be a maximum for a collinear geometry and vanishes when the angle between the donor, mediator, and acceptor is 90°. The indirect rate is compared with direct transfer between two chiral molecules. Insight is gained into discriminatory migration of energy in a dielectric medium.

Resonance energy transfer mediated by a chiral molecule

The problem of resonant energy transfer (RET) between an electric dipole donor, D, and an electric dipole acceptor, A, mediated by a passive, chiral third-body, T, is considered within the framework of molecular quantum electrodynamics theory. To account for the optical activity of the mediator, magnetic dipole and electric quadrupole coupling terms are included in addition to the leading electric dipole interaction term. Fourth-order diagrammatic time-dependent perturbation theory is used to obtain the matrix element. It is found that the Fermi golden rule rate depends on pure multipole moment polarizabilities and susceptibilities of T, as well as on various mixed electric and magnetic multipole moment response functions. The handedness of T manifests through mixed electric-magnetic dipole and mixed electric dipole-quadrupole polarizabilities, which affect the rate and, respectively, require the use of fourth-rank and sixth-rank Cartesian tensor averages over T, yielding non-vanishing isotropic rate formulae applicable to a chiral fluid medium. Terms of a similar order of magnitude proportional to the product of electric dipole polarizability and either magnetic dipole susceptibility or electric quadrupole polarizability of T are also computed for oriented and freely tumbling molecules. Migration rates dependent upon the product of the pure electric dipole or magnetic dipole polarizability with the mixed electric-magnetic or electric dipole-quadrupole analogs, which require fourth- and fifth-rank Cartesian tensor averaging, vanish for randomly oriented systems. Asymptotically limiting rate expressions are also evaluated. Insight is gained into RET occurring in complex media.

The British Association of Dermatologists' Undergraduate Curriculum Update 2021

The General Medical Council (GMC) plans to introduce a national Medical Licensing Assessment (MLA) in 2024 for all UK medical students as part of their primary medical qualification, with dermatology specified in its assessment blueprint. We present an Update to the British Association of Dermatologists' Undergraduate Curriculum, aligned both to the MLA Content Map and the GMC Outcomes for Graduates 2018.

Neuro-developmental Outcome of High Risk Neonates in a Tertiary Level Hospital

An observational longitudinal study was conducted in the Department of Neonatology and Child Developmental Center, Mymensingh Medical College Hospital (MMCH), Bangladesh during the period of September 2016 to February 2018 to find out the neuro-developmental outcome of high risk neonates at the age of 6 months. Five hundred seventy six (576) high risk neonate who were admitted in the neonatology department in Mymensingh Medical College Hospital were selected as study population by Purposive sampling technique. After admission written informed consent from parents or guardians obtained and Data was collected in a pre-designed case record form. At 6th months of age total 400 baby were came to Child Development Centre and their motor, cognition and behavior development were assessed by Bayley Scale of Infant Development and severity of cognitive, motor and behavior impairment were graded. All data were compiled, tabulated and then analyzed by computer software SPSS version 20.00. Mean age was 7.2±3.3 days. Among studied newborns 18.1% were preterm and 81.9% were term. Most of the newborn were male (63.0%). Developmental delay was found in 81.5% and neuro-developmental outcome was found normal in only 18.5% newborns. Significant delayed motor performance was found in 52% newborns where 17% had mild delay. Significantly delayed mental performance was found in 57.0% and 28.52% had mildly delayed mental performance. Non-optimal behavior was found in 57.0% newborns and14% had questionable behavior. Very low birth weight, preterm very low birth weight, home delivery, perinatal asphyxia and neonatal seizure were found to have significant relation with developmental delay. Most of the high risk neonates develop developmental delay.

Polariton mediated resonance energy transfer in a fluid

The focus of this work is on a microscopic quantum electrodynamical understanding of cumulative quantum effects in resonance energy transfer occurring in an isotropic and disordered medium. In particular, we consider quantum coherence, defined in terms of interferences between Feynman pathways, and analyze pure-amplitude and phase cross terms that appear in the Fermi golden rule rate equation that results from squaring the matrix element for mediated energy transfer. It is shown that pure-amplitude terms dominate in the near-zone when chromophores are close in proximity to one another (within a few nanometers), and phase cross terms dominate toward the far-zone when phase differences between different Feynman pathways begin to emerge. This can be understood in terms of physical attributes of the mediating photon, whose character becomes more real at long distances, coinciding with vanishing longitudinal components of the field, as transverse components begin to dominate.

Mediation of resonance energy transfer by two polarisable particles

The molecular quantum electrodynamics theory is employed to calculate the matrix element and Fermi golden rule rate for resonant transfer of electronic excitation energy between a donor and an acceptor in the vicinity of two neutral electric dipole polarizable particles, which play the role of bridging species. The emitter and absorber couple linearly to the electric displacement field via their electric dipole moments, while each mediator interacts quadratically with this field through its dynamic polarizability. This form of interaction Hamiltonian enables fourth-order perturbation theory to be used to compute the probability amplitude together with summation over 24 time-ordered diagrams representing a single virtual photon exchange between each pair of coupled particles. Expressions for the migration rate mediated by two inert molecules are obtained for an arbitrary arrangement of the four species that are in fixed mutual orientation or are freely tumbling. These formulae are valid for all interparticle separation distances outside the orbital overlap region. From the general result, rate equations applicable to an equidistant collinear configuration of the four bodies are evaluated. Near- and far-zone limiting forms of the transfer rate for the relay pathway are also calculated and exhibit inverse sixth and inverse square dependences on relative separation distances between pairs of particles, confirming the short-range (radiationless) and long-range (radiative) energy transfer mechanisms associated with two-body theory. The distance behavior of interference terms between two-, three-, and four-body terms is also examined, and the relative importance of each contribution to the total transfer rate is discussed.

A systematic review and meta-analysis of patient data from the West Africa (2013-16) Ebola virus disease epidemic

BACKGROUND

Over 28 000 individuals were infected with Ebola virus during the West Africa (2013-2016) epidemic, yet there has been criticism of the lack of robust clinical descriptions of Ebola virus disease (EVD) illness from that outbreak.

OBJECTIVES

To perform a meta-analysis of published data from the epidemic to describe the clinical presentation, evolution of disease, and predictors of mortality in individuals with EVD. To assess the quality and utility of published data for clinical and public health decision-making.

DATA SOURCES

Primary articles available in PubMed and published between January 2014 and May 2017.

ELIGIBILITY

Studies that sequentially enrolled individuals hospitalized for EVD and that reported acute clinical outcomes.

METHODS

We performed meta-analyses using random-effect models and assessed heterogeneity using the I2 method. We assessed data representativeness by comparing meta-analysis estimates with WHO aggregate data. We examined data utility by examining the availability and compatibility of data sets.

RESULTS

In all, 3653 articles were screened and 34 articles were included, representing 16 independent cohorts of patients (18 overlapping cohorts) and at least 6168 individuals. The pooled estimate for case fatality rate was 51% (95% CI 46%-56%). However, pooling of estimates for clinical presentation, progression, and predictors of mortality in individuals with EVD were hampered by significant heterogeneity, and inadequate data on clinical progression. Our assessment of data quality found that heterogeneity was largely unexplained, and data availability and compatibility were poor.

CONCLUSIONS

We have quantified a missed opportunity to generate reliable estimates of the clinical manifestations of EVD during the West Africa epidemic. Clinical data standards and data capture platforms are urgently needed.

P1943Ambient temperature and seasonal effects on blood pressure in 2.6 million Australians

Background

There is evidence that blood pressure (BP) levels vary considerably from season to season, due principally to variation in ambient temperature. This gives the potential for both under- and over-treatment if BP lowering medications are not varied seasonally, but is not acknowledged in clinical guidelines. We will describe the seasonal variation in BP and assess the association between systolic blood pressure (SBP) and outdoor maximum ambient temperature in Australia.

Methods

The primary care data is an extract from MedicineInsight, a national general practice data program developed and managed by NPS MedicineWise, which extracts deidentified data from almost 10% of all Australian general practices. We included patients aged 30–90 years with at least one BP measure recorded from 1 Jan 2010 to 1 Aug 2017. Australian Bureau of Meteorology daily max temperature is linked by matching observation dates and location to nearest weather station. Decomposition of the mean will determine seasonal variation. Multiple linear regression was used to estimate the associations between max temperature and SBP with adjustment for age, sex, socioeconomic index, current smoking, comorbidities, BP lowering medication use, lipid lowering medication use and year of BP measurement.

Results

The study population includes 2.6 million people, mean age 55 years (standard deviation [SD] 16.3). Fifty-five percent are female, over a third of the cohort reside in New South Wales, and 62.4% reside in major Australian cities. The mean (SD) temperature was 23°C (6.6).

There was a mean (SD) of 7 (11.4) BP measurements per person over the study period, median 3 measures (interquartile range 1–8). A quarter had a history of hypertension, 8% had a history of cardiovascular disease, and 8% had a history of diabetes. Twenty-six percent had at least one prescription for BP lowering therapy.

The average monthly SBP for the cohort demonstrated strong seasonal variation with higher values in winter. The population mean varies by 3mmHg SBP between seasons across Australia, ranging from 1.7mmHg in the Northern Territory to 3.5mmHg in South Australia (range of mean maximum temperature 3°C [30–33] and 14°C [15–29] for the capital cities respectively). Each 10°C increase in max outdoor temperature was associated with a 1.8mmHg [95% CI 1.80–1.83] lower mean SBP. The proportion of people with SBP>140mmHg varied by season, irrespective of age, sex and use of BP lowering treatment. For example, among those treated control rates varied between 70 and 81%, and among those not treated between 78 and 85% (Figure).

Blood pressure seasonality in Australia

Conclusions

BP control rates vary considerably by season. These findings have implications for the reliable diagnosis of hypertension, and suggest seasonal adjustments in treatment should be considered for some patients. The clinical and public health relevance of this phenomenon is expected to increase with increasing climate variability.

Acknowledgement/Funding

National Health and Medical Research Council Australia, National Heart Foundation Australia

P5732Effects of blood pressure lowering drugs in heart failure: a systematic review and meta-analysis of randomised controlled trials

Background

Observational studies have reported a J-shaped relationship between blood pressure (BP) and all-cause and cardiovascular mortality in patients with heart failure (HF). Although decreasing BP significantly reduces the risk of fatal and non-fatal cardiovascular outcomes in the general population across a range of baseline BP categories, the extent to which those findings are applicable to HF patients and whether the relationship holds true when baseline BP is very low remain unclear. Therefore, it is yet to be established whether the observed J-shaped relationship between BP and clinical outcomes in patients with HF is causal and/or modified by antihypertensive treatment.

Purpose

We aimed to combine evidence from all HF trials that have investigated the effects of drugs with BP-lowering properties to assess (1) the extent to which such drugs reduce BP in HF, (2) the association between the net change in BP between treatment arms and cause-specific outcomes, and (3) whether treatment effects (including benefits and potential harms) vary according to baseline BP.

Methods

We conducted a systematic review and meta-analysis including randomised clinical trials of drugs with BP-lowering properties conducted in patients with chronic HF with at least 300 patient-years follow-up.

Results

We included a total of 37 trials (91,950 patients) and showed that treatment with drugs with BP-lowering properties significantly reduced SBP by 2.0 mmHg in all trials and by 2.4 mmHg in placebo-controlled trials (Figure 1). There was no evidence that BP reduction in placebo-controlled trials varied across strata of baseline BP, but there was suggestive evidence for differential effects by drug class, with renin-angiotensin-aldosterone system inhibitors reducing SBP by 3.2 mmHg (95% CI [−4.0, −2.4]), whilst BB appeared to have a neutral effect on BP. There was no evidence that the relative risk reduction afforded by treatment with BP-lowering drugs on all-cause mortality, cardiovascular mortality and HF hospitalisation was significantly different across categories of baseline BP. There was also no strong evidence for heterogeneity of treatment effect on adverse events leading to treatment discontinuation by baseline BP. Meta-regression did not show significant associations between the magnitude of BP reduction achieved in each trial and risk of those clinical outcomes.

Figure 1

Conclusions

Treatment with drugs with BP-lowering properties resulted in a small but significant decrease in SBP in patients with HF irrespective of baseline BP. There was no evidence that the effects of those drugs differed across the range of baseline SBP, thus supporting the efficacy and safety of those drugs in patients with low baseline BP. Data from published reports was insufficient to adequately investigate whether BP-dependent mechanisms contribute to the effect of BP-lowering drugs on clinical outcomes in patients with HF.

Acknowledgement/Funding

None

A Quantum Electrodynamics Description of Quantum Coherence and Damping in Condensed-Phase Energy Transfer

Quantum coherence in condensed-phase electronic resonance energy transfer (RET) is described within the context of quantum electrodynamics (QED) theory. Mediating dressed virtual photons (polaritons) are explicitly incorporated into the treatment, and coherence is understood within the context of interfering Feynman pathways connecting the initial and final states for the RET process. The model investigated is that of an oriented three-body donor, acceptor, and mediator RET system embedded within a dispersive and absorbing polarizable medium. We show how quantum coherence can significantly enhance the rate of RET and give a rigorous picture for subsequent decoherence that is driven by both phase and amplitude damping. Energy-conserving phase damping occurs as a result of geometric and dispersive effects and is associated with destructive interference between Feynman pathways. Dissipative amplitude damping, on the other hand, is attributed to vibronic relaxation and absorptivity of the medium and can be understood as virtual photons (polaritons) leaking into the environment. This model offers insights into the emergence of coherence and subsequent decoherence for energy transfer in photosynthetic systems.

Air pollution tolerance index of Mangifera indica plant species growing in the greater Dhaka region, Bangladesh

Air pollution tolerance index (APTI) of the mango (Mangifera indica) leaves growing in the greater Dhaka region, Bangladesh was studied. Leaf samples were collected in winter season from both roadsides and residential locations of different parts of greater Dhaka region. The APTI values of the leaves were calculated from the total chlorophyll content (TCC), ascorbic acid concentration, relative water content (RWC), and pH of the leaf extract. Determined APTI values were compared with Particulate Matter (PM2.5) values in each sampling location. TCC and ascorbic acid concentration were determined with a UV-Visible spectrophotometer. TCC values varied between 0.25 and 1.10 mg/g with an average of 0.66 mg/g. The average concentration of ascorbic acid was 2.21 mg/g (values ranging from 0.33 to 3.24 mg/g) and the RWC varied from 81.5% to 97.4%. Moreover, pH values of the leaf extracts were found acidic (4.48-5.78). The average APTI values varied depending on the locations with a total average of 10.1. However, the average APTI value in the residential area (10.5) was slightly higher compared to roadsides (9.70) indicating the existence of high-level pollutions at the roadsides. The highest APTI value was observed in Dhaka city sampling location (10.6) where the lowest value was found in Narayangonj (9.70). APTI values showed a strong correlation with particulate matter concentrations (PM2.5). These results suggest that Mangifera indica is very sensitive to the air pollutants. J. Biodivers. Conserv. Bioresour. Manag. 2019, 5(1): 1-12

Assessing risk to human health for heavy metal contamination through street dust in the Southeast Asian Megacity: Dhaka, Bangladesh

Contaminants in road dusts can directly pose significant human health risks through oral ingestion, particle inhalation, and dermal contact. Therefore, this study has been designed to analyze heavy metal contaminations in 88 street dusts collected from the 22 high traffic sites and industrial areas of the Southeast Asian Megacity: Dhaka (capital of Bangladesh) using energy dispersive X-ray fluorescence (EDXRF) spectroscopy. This study revealed that the maximum Pb, Cd, Zn, Cr, Ni, As, Mn and Cu contents in the street dust samples were 18.9, 11.6, 239.2, 144.3, 37.1, 8.1, 261.5 and 49.6 mg/ kg respectively in which Ni and Pb concentration were 2 times, and Cd concentration was 200 times higher than the background level in soil; and As concentration was slightly higher than soil background level. The spatial distribution of heavy metal concentrations in street dust samples in Dhaka City was revealed that the hot spot areas of Pb, Ni, Cd and As were mainly associated with heavy traffic and industrial activities. The risk assessment strategies were used for this study for identifying the routes of exposure through oral ingestion, inhalation, and dermal contact by the fine particles (~75 μm) of street dust, especially for children based on the US EPA health risk models. Both non-carcinogenic and carcinogenic risks of heavy metals were characterized in street dust samples. Results based on the hazard index (HI), in the case of non-cancer effect, the ingestion of dust particles of children and adults in Dhaka City appeared to be the route of exposure to street dust that results in a higher risk for heavy metals, followed by dermal contact. This study revealed that the inhalation of re-suspended particles through mouth and nose were almost negligible. It was also noticed that children were experiencing the potential health risk due to HI for Cr (1.04), which was slightly higher than the safe level 1, and Cd (0.69) was close to the safe level 1. Reversely, cancer risk for Cr (i.e. 4.27 × 10^-6) was fallen within the range of threshold values (10^-4 to 10^-6) and As (i.e. 9.59 × 10^-7) was close to the upper limit of threshold values (10^-4 to 10^-6).

Near-Zone Mediation of RET by One and Two Proximal Particles

The effect of two inert, electric dipole polarizable molecules in relaying electronic excitation energy resonantly between a donor-acceptor pair is studied within the framework of molecular QED theory. Since transfer is efficacious when the coupled particles are close to one another, the matrix element is calculated in the near-zone approximation by employing static dipolar interaction potentials and third-order diagrammatic perturbation theory. For isotropic species, the Fermi golden rule exchange rate exhibits a Förster-like inverse sixth power dependence on each pair separation distance, is proportional to the modulus squares of the transition electric dipole moments of donor and acceptor, and depends on the polarizabilities of the two mediators. Comparison is made with direct (2-body) and third-body mediated near-zone transfer. Matrix elements for these last two processes are used to evaluate contributions to the rate due to 2-body-3-body, 2-body-4-body, and 3-body-4-body interference terms. In each of these cases, an inverse cubic dependence on each of the relative particle displacements is found.

Perspective: Quantum Hamiltonians for optical interactions

The multipolar Hamiltonian of quantum electrodynamics is extensively employed in chemical and optical physics to treat rigorously the interaction of electromagnetic fields with matter. It is also widely used to evaluate intermolecular interactions. The multipolar version of the Hamiltonian is commonly obtained by carrying out a unitary transformation of the Coulomb gauge Hamiltonian that goes by the name of Power-Zienau-Woolley (PZW). Not only does the formulation provide excellent agreement with experiment, and versatility in its predictive ability, but also superior physical insight. Recently, the foundations and validity of the PZW Hamiltonian have been questioned, raising a concern over issues of gauge transformation and invariance, and whether observable quantities obtained from unitarily equivalent Hamiltonians are identical. Here, an in-depth analysis of theoretical foundations clarifies the issues and enables misconceptions to be identified. Claims of non-physicality are refuted: the PZW transformation and ensuing Hamiltonian are shown to rest on solid physical principles and secure theoretical ground.

Expulsion of a Lacrimal Dacryolith by Sneezing: A Rare Event

Purpose

To describe the case of a man presenting with intermittent epiphora of the right eye and a low grade dacryocystitis due to a dacryolith.

Methods/Results

He was treated conservatively and was offered a Dacryocystorhinostomy. A few weeks before surgery, he developed swelling and pain over the right medial canthus followed by violent sneezing with spontaneous extrusion of the dacryolith.

Discussion

The authors propose that the dacryolith fragmented spontaneously and once it reached the nasal cavity, was expelled by violent sneezing to the nostril, a mechanism not previously reported.

Conclusions

Reformation of dacryolith is a likely possibility, and recurrence of symptoms in such cases may ultimately require a Dacryocystorhinostomy.

Outcomes for severe aponeurotic ptosis using posterior approach white-line advancement ptosis surgery

PurposeThe purpose of the study was to report the outcome of posterior approach white-line advancement surgery for severe involutional aponeurotic ptosis.Patients and methodsThis was a retrospective review of an interventional case series of all patients undergoing surgery for severe involutional aponeurotic ptosis during a 42-month period at a single center. The inclusion criteria were severe involutional ptosis (upper eyelid margin reflex distance (MRD) ≤1 mm) undergoing posterior approach surgery. There was minimum 3-month follow-up. The main outcome measures were type of ptosis (primary or recurrent), preoperative margin reflex distance, levator function and eyelid skin crease height, presence of visible iris sign (VIS), documented unusual intraoperative findings, postoperative complications, and follow-up time.ResultsOf the 836 procedures for ptosis, 122 procedures (76 patients) met the inclusion criteria for this study. Mean postoperative follow-up was 28 (median 18, range 12-98) weeks. Success rates were 80.3% (98/122) overall, 81.5% (66/81) in the non-VIS group, and 78% (32/41) in the VIS group. There was no significant difference between the two groups (P=0.411). Failures were due to undercorrection, with <2 mm MRD in 75% (18/24), overcorrection with >4.5 mm MRD in 16.7% (4/24), and inter-eyelid height asymmetry of >1 mm in 8.3% (2/122).ConclusionsOutcomes of ptosis surgery for severe aponeurotic ptosis using a posterior approach white-line advancement are comparable to, and possibly better than, anterior approach in eyelids with VIS.

Enhanced Chiral Discriminatory van der Waals Interactions Mediated by Chiral Surfaces

We predict a discriminatory interaction between a chiral molecule and an achiral molecule which is mediated by a chiral body. To achieve this, we generalize the van der Waals interaction potential between two ground-state molecules with electric, magnetic, and chiral response to nontrivial environments. The force is evaluated using second-order perturbation theory with an effective Hamiltonian. Chiral media enhance or reduce the free interaction via many-body interactions, making it possible to measure the chiral contributions to the van der Waals force with current technology. The van der Waals interaction is discriminatory with respect to enantiomers of different handedness and could be used to separate enantiomers. We also suggest a specific geometric configuration where the electric contribution to the van der Waals interaction is zero, making the chiral component the dominant effect.

Clinical and anthropological perspectives on chemical relaxing of afro-textured hair

The culturally engrained practice of 'relaxing' afro-textured hair has been linked with hair and scalp disorders. Herein, we discuss the evolution of human hair types, focusing in particular on afro-textured hair. We explore the biological features of this hair type, and discuss the different methods employed to straighten afro-textured hair, focusing in particular on chemical straightening. We also examine clinical, anthropological, and psychological issues associated with this latter practice. Examples of common scalp pathologies associated with chronic hair relaxing, such as alopecia, hair breakage, caustic burns and irritant contact dermatitis, are also highlighted. The data presented herein should enable clinicians to engage in culturally appropriate discussions with their patients about issues of appearance and conformity.

Whole-exome sequencing improves mutation detection in a diagnostic epidermolysis bullosa laboratory

BACKGROUND

Subtypes of inherited epidermolysis bullosa (EB) vary significantly in their clinical presentation and prognosis. Establishing an accurate diagnosis is important for genetic counselling and patient management. Current approaches in EB diagnostics involve skin biopsy for immunohistochemistry and transmission electron microscopy, and Sanger sequencing of candidate genes. Although informative in most cases, this approach can be expensive and laborious and may fail to identify pathogenic mutations in ~15% of cases.

OBJECTIVES

Next-generation DNA sequencing (NGS) technologies offer a fast and efficient complementary diagnostic strategy, but the value of NGS in EB diagnostics has yet to be explored. The aim of this study was to undertake whole-exome sequencing (WES) in nine cases of EB in which established diagnostic methods failed to make a genetic diagnosis.

METHODS

Whole-exome capture was performed using genomic DNA from each case of EB, followed by massively parallel sequencing. Resulting reads were mapped to the human genome reference hg19. Potentially pathogenic mutations were subsequently confirmed by Sanger sequencing.

RESULTS

Analysis of WES data disclosed biallelic pathogenic mutations in each case, with all mutations occurring in known EB genes (LAMB3, PLEC, FERMT1 and COL7A1). This study demonstrates that NGS can improve diagnostic sensitivity in EB compared with current laboratory practice.

CONCLUSIONS

With appropriate diagnostic platforms and bioinformatics support, WES is likely to increase mutation detection in cases of EB and improve EB diagnostic services, although skin biopsy remains an important diagnostic investigation in current clinical practice.

Abstract P1-06-11: Tumor-associated macrophages: CD206 expression and patient outcomes in locally advanced breast cancer

Introduction

The ability of a tumor to recur is related to the complex molecular biology of the tumor cells and the surrounding microenvironment. Tumor-associated macrophages (TAMs) account for up to 50% of the cell mass within a breast tumor, and the M2 macrophage phenotype has been reported to have pro-tumor activity. The mannose receptor, CD206, is a transmembrane receptor expressed predominantly in macrophages and shown in mouse studies to promote M2/TAM activity. This study evaluates CD206 expression in the tumor stroma with patient outcomes in locally advanced breast cancer.

Methods

The Scott & White tumor registry was queried for consecutive cases of women diagnosed with stage 3, HER-2 negative breast cancer between January 1999 and December 2006. To meet inclusion criteria, all biopsies must have been performed at S&W and patients must have had at least 5 years of follow up in our system documenting status of cancer (complete remission vs. metastatic recurrence). Archived formalin fixed and paraffin embedded tissue breast tissue from initial surgical biopsies was obtained from the Scott & White Pathology Department. Sections were cut at 4 microns thick and slides were stained for CD206. Two pathologists without knowledge of the patients’ clinical backgrounds reviewed each slide. The hot spot method was employed at 20x power to identify the 3 spots in tumor stroma that stained most heavily. The number of CD206+ cells in each of 3 hot spots was counted, and the mean number of CD206+ cells per hot spot reported by two independent pathologists was averaged for analysis.

Results

65 patients met inclusion criteria, of these 31 had a recurrence within 5 years of diagnosis. There was no correlation between likelihood of recurrence or overall survival and CD206 expression. In the 31 patients that had a recurrence, a high CD206 count of greater than or equal to 15 was associated with a shorter time to recurrence than a CD206 count of less than 15 (14.8 months vs. 22 months, respectively, p = 0.028). Mean age at diagnosis in the recurrence group was 59.6 vs. 60 years, and 15 (60%) vs. 2(33%) patients were ER positive in the low CD206 (&lt;15) vs. high CD206 ( = &gt;15) groups, respectively.

Conclusion

High expression of CD206 in the tumor stroma was associated with a shorter time to recurrence in patients with stage 3, HER-2 negative breast cancer; however, there were more ER negative tumors in the high CD 206 group. Our research supports in vitro data that high CD206 expression in macrophages may represent a more aggressive tumor phenotype. Future studies focusing on studying CD206 expression in HER-2 positive breast tumors along with histological stratification are needed to confirm this finding.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-06-11.

Assessment in Undergraduate Medical Education: Bangladesh Perspectives

Background: Medical education in Bangladesh is totally controlled by the Government and run a unique undergraduate curriculum throughout the country in both public and private sectors. This paper is aimed to briefly describe the medical education reform in Bangladesh and suggests further assessment changes. The present official form of undergraduate medical curriculum has first evolved in 1988 followed by revision in 2002 and 2012. Assessment and teaching are the two sides of the same coin. Assessment drives learning and learning drives practices. Following the curriculum reform since 2002, the assessment in undergraduate medical education has been greatly changed. There are a lot of in-course formative assessments which include item examination, card final and term final, designed to improve the quality of education. Ten percent marks of summative written examinations derive from formative assessment. Traditional oral examination has been changed to structured form to ensure greater reliability. Even then, teachers are not yet building up to conduct oral examination in such a structured way. Examiners differ in their personality, style and level of experience with variation of questioning and scoring from student to students. Weakness of reliability on oral examination still exists. Students also feel very stressful during the oral examinations. Moreover, to conduct such oral examination, three to four months times per year are lost by the faculties which can be efficiently utilised for teaching and research purposes. Worlds' leading medical schools now-a-days used oral examination only for borderline and distinction students. Bangladesh also must consider oral examination only for borderline and distinction students. DOI: http://dx.doi.org/10.3329/bjms.v12i4.16658 Bangladesh Journal of Medical Science Vol. 12 No. 04 October ’13 Page 357-363