Supersensitive Detection of Anions in Pure Organic and Aqueous Media by Amino Acid Conjugated Ellman's Reagent

The last few decades witnessed a remarkable advancement in the field of molecular anion receptors. A variety of anion binding motifs have been discovered, and large number of designer molecular anion receptors with high selectivity are being reported. However, anion detection in an aqueous medium is still a formidable challenge as evident from only a miniscule of synthetic systems available in the literature. We, herein, report 5,5'-dithio-bis(2-nitrobenzoic acid) (Ellman's reagent) appended with amino acids as supersensitive anion sensors that can detect F^- and H₂PO₄^- ions in both aqueous as well as organic media. Interestingly, the sensors showed a dual response to anions, viz., chromogenic response in organic medium and electrochemical response in aqueous solutions. Various spectroscopic techniques such as UV-vis and ¹H NMR are used to investigate the binding studies in acetonitrile, whereas electrochemical methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) are employed to explore the anion binding in water. The host-guest complex stoichiometry and binding constants are calculated using the BindFit software. The geometry of host-guest complex has been optimized by the density functional theory (DFT) method. These molecules are versatile sensors since these function in both water and acetonitrile with extremely low limit of detection (LOD) up to 0.07 fM and limit of quantification (LOQ) up to 0.23 fM. To our knowledge, the present system is the first example of a sensor that can detect the lowest concentration of anions in water quantitatively. The minimalistic design strategy presented here opens up the innumerable possibilities for designing dual anion sensors in a one fell swoop.

Maternal and fetal outcomes of lupus pregnancies: A collective effort by Karnataka Rheumatologists

INTRODUCTION

Identifying factors predicting adverse pregnancy outcomes involving systemic lupus erythematosus (SLE) is a research priority. The aims of this study were to investigate (a) the maternal and fetal outcomes of pregnant lupus patients and the factors associated with adverse pregnancy outcomes, and (b) the effect of pregnancy on lupus disease activity of these patients.

METHODS

This was an ambi-directional study collecting information from five multi-specialist referral centres across the state of Karnataka, India over 5 years (2013-2018). Clinical details of pregnancies and outcomes that were temporally associated with lupus disease were recorded using a structured pro forma. The Safety of Estrogen in SLE National Assessment-SLE Disease Activity Index (SELENA-SLEDAI) was used to assess lupus activity during the 6 months prior to pregnancy and the intra- and post-partum periods. Modifications suggested in the SLE Pregnancy Disease Activity Index were considered while scoring.

RESULTS

A total of 121 pregnancies in 80 SLE patients with a mean age of 27.1 (±4.5) years and with a mean disease duration of 4.6 (±4.1) years were reviewed. Largely patients were in clinical remission (109/121; 90.1%). Antiphospholipid antibody positivity was seen in 45/121 (37.2%) patients. A history of lupus nephritis was noted in 29/121 (24%) patients. Maternal complications (32%) were mainly due to hypertensive disorders of pregnancy (HDP; 19/121; 15.7%). Adverse fetal outcomes (58%) were mainly in the form of spontaneous first-trimester abortions (21/121; 16%), stillbirth (14/121; 11.6%) and prematurity (24/121; 20%). HDP is strongly associated with stillbirth and prematurity and is independent of active lupus. Disease activity was associated with a three-fold increased risk of adverse fetal outcome in univariate analysis. The risk of major flare during pregnancy is low (4.1%) when conception occurs during stable disease. Hydroxychloroquine (HCQ) use was associated with reduced risk of flare (p = 0.001) in patients in remission at the time of conception.

CONCLUSIONS

The risk of major flare during pregnancy is low when conception happens during stable disease. HCQ use was associated with reduced risk of flare in patients in remission at the time of conception. HDP was strongly associated with stillbirth and prematurity and are independent of active lupus in our cohort.

AB0785 REAL LIFE EXPERIENCE OF METHOTREXATE BASED DUAL COMBINATION DMARDS IN PSORIATIC ARTHRITIS- RESULTS FROM KARNATAKA PSORIATIC ARTHRITIS COHORT (KPsAC)

Background:

Biologics have been the focus of recent treatment guidelines and ‘Treat to Target’ strategies for both psoriasis (PsO) & psoriatic Arthritis (PsA). However, in day-today practice, combination DMARDs anchored around methotrexate are mainstay in majority of patients.

Objectives:

To describe experience and effectiveness of Methotrexate in combination with conventional DMARDs in Karnataka Psoriatic Arthritis Cohort.

Methods:

Treatment information was extracted from KPsAC (n=549) which is a cross sectional, non-interventional study conducted across 17 rheumatology practicing centres in Karnataka, India using a structured proforma. This study was approved by respective Ethical committee. Information on efficacy was extracted for various csDMARDs in combination with methotrexate. Standard disease activity outcome measures were used for assessing the response to therapy (DAPSA, PASI, HAQ, MDA5). All participating rheumatologists underwent training to calculate PASI and other outcome scores.

Results:

Nearly half of the patients in our cohort were on methotrexate (44%) monotherapy. Proportion of patients who received combination csDMARD anchored on methotrexate were 29%. The choice of add on csDMARD was as per clinician discretion or subject preference. Patients were divided in to three groups based on treatments they were receiving at the time of study: Methotrexate (Mtx)+Leflunomide (Lef), Mtx+Sulfasalazine (SSz) and Mtx+Apremilast(Apr). Their characteristics along with outcome measures are depicted in table 1. In Mtx+Apr group: remission or low disease activity was present in 42%, HAQ score of <0.5 was seen in 82%, and only one patient had a PASI of > 10. PASI was significantly lower in the Mtx+Apr group compared to Mtx+Lef group (p<0.009) and Mtx +Ssz group (p < 0.020)

Conclusion:

Apremilast is an orally administered, small molecule inhibitor of phosphodiesterase 4 (PDE4)**. In this observational study, 3 groups of methotrexate plus csDMARD- leflunomide, sulphasalazine and apremilast fared similarly for articular domain of PsA. However, in cutaneous domain, PASI was significantly lower in apremilast + methotrexate group. To our knowledge, this is the first real life report of the use of combination DMARDs in unselected PsA patients demonstrating effectiveness of apremilast in cutaneous domain. Methotrexate remains anchor DMARD for treatment of PsA in 2/3rdof PsA patients. Addition of apremilast to methotrexate inadequate responders appears to be beneficial in PsA with persistent cutaneous disease. However, being an observational study, this needs to be confirmed in controlled clinical trials.

References:

**Apremilast: A Review in Psoriasis and Psoriatic Arthritis, Drugs March 2017, Volume 77, Issue 4.

Table.

Characteristics and comparison of combination csDMARDs

MTX+SSZ(N=39)MTX+LEF (n=77)MTX+APR(N=45)Median Age (years)373935Median disease duration (months)96101112Enthesitis (Ever)6(15%)21(27%)4(8%)Dactylitis (Ever)9((23%)28(36%)12 (26%)DAPSA < 46(15%)9(11%)10(22%) 4-1414(36%)25(32%)13(29%) 14-287(18%)24(31%)11(24%)PASI >107(18%) #14(18%) *1(2%) *#HAQ < 0.530(77%)60(78%)37(82%)MDA 5 achieved16(41%)25(32%)19(42%)

*P value < 0.009 #P value <0.02

Disclosure of Interests:

None declared

AB0790 CLINICAL PROFILING OF PSORIATIC ARTHRITIS (PsA): AN OBSERVATIONAL STUDY FROM A SOUTH INDIAN PSORIATIC ARTHRITIS COHORT

Background:

Clinical patterns and disease burden of PsA varies in different parts of the world. Demographic studies from Indian subcontinent are sparse

Objectives:

To study the cutaneous, articular profile of PsA and describe their disease activity, disability and co-morbidities (CMs)

Methods:

This is a multicenter, cross-sectional, non-interventional study from Karnataka, India. All consecutive PsA patients defined by CASPAR or expert diagnosis were evaluated over 8 months from 17 Rheumatology centers across Karnataka using standard parameters such as PASI, DAPSA, Indian version of HAQ-DI1, psoriatic co-morbidity index2(Cidx) and MDA 5. Patient consent and EC obtained

Results:

549 PsA patients were evaluated and their disease characteristics are shown in Table 1 & 2. PsA preceded psoriasis in in 81 (14.7%).

Table 1.

Patient characteristics (n=549)

DEMOGRAPHICSPsACommonest age group of PsA (yrs)31-40PsA SubclassificationM:F6:5Symmetric polyarthritis216(40.7%)Type 1 PsoriasisType 2 Psoriasis279(55.8%)221(44.2%)Mean duration (yrs)Asymmetric oligoarthritis202(38.1%)Psoriasis8.8(±7.8)DIP predominant88(16.6%)PsA5.2(±6.3)Arthritis mutilans16(4.2%)PsA preceded psoriasis81(14.7%)Dactylitis182(33.9%)Family h/oPsoriasis107(19.7%)Enthesitis109(20.3%)PsA33(6%)Mean TJC686.3(±8.9)AS11(2%)Mean SJC683.5(±5.2)Uveitis5(0.9%)Type of PsoriasisPlaque253(59.9%)IBD3(0.5%)Erythrodermic 31(7.3%)

Type I & II psoriasis did not differ in PASI, DAPSA, HAQ-DI or having a family h/o psoriasis. Type II psoriasis had higher Cidx than type I (p=0.0001). Pt pain VAS, DAPSA, PhyGA, PtGA & SJC significantly correlated with higher HAQ-DI (p<0.0001). TJC, ESR, CRP & PASI had minor correlation with HAQ-DI. Females had higher HAQ-DI compared to males (p=0.02). Knee joint involvement caused disability most frequently. Cidx was higher in males (p=0.008). Minor correlation was found between Cidx with age, HAQ-DI & DAPSA. Mean BMI of our cohort was 26.8(±14.8) kg/m2. 56.5% were overweight. Higher BMI was not associated with age, duration of arthritis, DAPSA, PASI, HAQ-DI & Cidx.

Infections (any time) were recorded in 10.8%, of which skin was the commonest site in 38.9%; 30.5% of these needed hospitalizations.

Conclusion:

Despite mild skin disease in majority, more than half of the patients have moderate to severe joint activity. Mild to moderate functional disability in nearly half of our cohort indicate high burden of damage. High incidence of co-morbidities in PsA compared with general population is in line with published literature. In addition to aggressive control of articular activity, detection and control of co-morbidities must be an integral part of PsA management.

References:

[1]https://doi.org/10.1093/rheumatology/41.12.1457

[2]http://dx.doi.org/10.1136/annrheumdis-2016-eular.4598

Table 2.

Disease characteristics

DISEASE ACTIVITYDISABILITYCO-MORBIDITIESMean PASI: 3.8(7.4)Mean HAQ-DI: 0.3(0.45)Mean Cidx: 0.98(1.6)Mild (PASI 0-5)480(80%)Mild-mod disability260(48.2%)N with 1 or more CMs232(42.3%)Severe (>10)57(10.6%)ADL with most frequent disabilityClimbing a flight of stairs 189(35%)HTNT2DMSmokingPsA severity19.8%16.6%5.4%3.2%Mean DAPSA: 18.8(16.6)ADL with highest disability scoreSitting cross-legged/squattingAnxietyIHDDyslipidemiaOthers3.1%2.3%2%<2% eachRemission100(19.9%)Low DA145(28.8%)Moderate DA137(27.2%)High DA123(24.5%)Family h/o CV dis/stroke72(15.2%)

Disclosure of Interests:

None declared

Effect of ionic liquid on the fluorescence of an intramolecular exciplex forming probe

The effects of ionic liquid addition on the spectroscopic properties of a pyrene-tryptophan-containing fluorescent intramolecular complex in polar-aprotic and polar-protic solvents, specifically, acetonitrile and ethanol, are assessed. Two ionic liquid sets, consisting of seven different ionic liquids, were explored; set 1 comprised three imidazolium-containing ionic liquids paired with different anions while set 2 consisted of varying cations, namely, imidazolium, pyrrolidinium, ammonium, and pyridinium, partnered with a common anion, bis(trifluoromethylsulfonyl)imide ([Tf2N-]). The results provided herein reveal that all ionic liquids explored behave as quenchers, however, the imidazolium-, pyrrolidinium-, and ammonium-containing ionic liquids selectively quenched the fluorescence from the exciplex while the monomer emission from pyrene was largely unaffected relative to exciplex emission. Conversely, the pyridinium ionic liquid, significantly quenched the fluorescence from both the pyrene monomer and the pyrene-tryptophan exciplex, as was expected. The observed quenching is demonstrated to originate from the cations of the ionic liquids and is, in general, more efficient for an imidazolium ionic liquid that contains an acidic proton in the C2 position. Stern-Volmer plots of the exciplex quenching demonstrate a complex quenching mechanism that does not appear to follow any conventional quenching models with the data best fit to an exponential equation. Furthermore, time-resolved fluorescence measurements reveal that the quenching is not dynamic in nature as the recovered decay times do not systematically decrease with increasing ionic liquid concentration, suggesting a possible static quenching mechanism. Thus, the formation of a "dark" ensemble is proposed, in which the ionic liquid cations complex with or crowd around the exciplex, quenching the intramolecular energy transfer.

Unprecedented formation of reverse micellar vesicles from psuedopeptidic bottlebrush polymers

Self-assembly of psuedopeptidic polymers to vesicles is reported and the mechanism of this spherical assembly has also been delineated.

Revealing Signs and Hidden 1H NMR Coupling Constants in Three-Spin Systems Using Long-Lived Coherences

Long-lived coherences (LLCs) in a pair of coupled protons have long lifetimes and hence decreased line width and increased spectral resolution. Fourier transformation of the damped oscillatory decay of the LLC also provides coupling information on the spin system. In a three-spin system, unlike in the two-spin case, the peaks in an LLC spectrum are observed at combinations of the coupling constants. This attribute is used to determine the relative signs of the coupling constants in weakly and strongly coupled model systems. In addition, it is shown that a coupling constant in a three-spin system that is unobservable in the ¹H NMR spectrum, as is the case in bispidinone, a molecule of significance in peptidomimetics, may be determined from the LLC spectrum.

Glutamic acid-based dendritic peptides for scaffold-free cartilage tissue engineering

Current treatment modalities for cartilage regeneration often result in the production of fibrous-type cartilage tissue at the defect site, which has inferior mechanical properties as compared to native hyaline cartilage. Further, effective treatments are not available at present, for preventing age-related as well as disease-related hypertrophic development of chondrocytes. In the present study, we designed and synthesized three sets of glutamic acid-based dendritic peptides, differing in degree of lipidation as well as branching. Each set constitutes of N-terminal protected as well as corresponding N-deprotected peptides. Altogether, six peptides [BE12, E12, BE3(12)4, E3(12)4, BE3OMe, E3OMe] were tested for their chondrogenesis enhancing potential in vitro, using rabbit adipose derived mesenchymal stem cells (ADMSCs). Immunohistochemical and gene expression studies as well as biochemical analyses revealed that the lipopeptides [E12 and BE3(12)4] are able to enhance chondrogenic differentiation of ADMSCs significantly (p < 0.001) as compared to control group (chondrogenic medium alone). Glycosaminoglycan content, and the chondrogenic marker genes like Aggrecan (Acan), Type II collagen (Col2a1), Hyaluronan synthase 2 (Has2), and SRY-box 9 (Sox9) expressions were found to be significantly increased in E12 and BE3(12)4 treated groups. Most importantly, the BE3(12)4 treated group showed significantly lower Type I collagen (Col1a2) and Type X collagen (Col10a1) transcript levels (p < 0.001), indicating its potential for hyaline cartilage formation and also to prevent hypertrophic development. Thus, the lipopeptides E12 and BE3(12)4 may be useful for preventing chondrocyte hypertrophy and realizing the hyaline nature of regenerated cartilage tissue in tissue engineering. STATEMENT OF SIGNIFICANCE: The current treatment modalities for degenerative cartilage diseases are unsatisfactory as the resultant regenerated cartilage is often fibrous in nature with inferior mechanical properties. Further, there is no proper treatment available for age-related development of chondrocyte hypertrophy at present. In this study we synthesized glutamic acid-based lipopeptides, which differ in the degree of lipidation as well as branching. We used a combinatorial approach of scaffold-free tissue engineering and dendritic lipopeptides to achieve hyaline-like cartilage tissue from adipose derived mesenchymal stem cells in vitro. Gene expression analysis revealed the down regulation of fibrous cartilage marker Col1a2 and hypertrophic marker Col10a1, suggesting that these lipopeptides may be useful for achieving mechanically superior hyaline cartilage regeneration in future.

Designer Peptide and Protein Dendrimers: A Cross-Sectional Analysis

Dendrimers have attracted immense interest in science and technology due to their unique chemical structure that offers a myriad of opportunities for researchers. Dendritic design allows us to present peptides in a branched three-dimensional fashion that eventually leads to a globular shape, thus mimicking globular proteins. Peptide dendrimers, unlike other classes of dendrimers, have immense applications in biomedical research due to their biological origin. The diversity of potential building blocks and innumerable possibilities for design, along with the fact that the area is relatively underexplored, make peptide dendrimers sought-after candidates for various applications. This review summarizes the stepwise evolution of peptidic dendrimers along with their multifaceted applications in various fields. Further, the introduction of biomacromolecules such as proteins to a dendritic scaffold, resulting in complex macromolecules with discrete molecular weights, is an altogether new addition to the area of organic chemistry. The synthesis of highly complex and fully folded biomacromolecules on a dendritic scaffold requires expertise in synthetic organic chemistry and biology. Presently, there are only a handful of examples of protein dendrimers; we believe that these limited examples will fuel further research in this area.

Maximizing RNA Loading for Gene Silencing Using Porous Silicon Nanoparticles

Gene silencing by RNA interference is a powerful technology with broad applications. However, this technology has been hampered by the instability of small interfering RNA (siRNA) molecules in physiological conditions and their inefficient delivery into the cytoplasm of target cells. Porous silicon nanoparticles have emerged as a potential delivery vehicle to overcome these limitations-being able to encapsulate RNA molecules within the porous matrix and protect them from degradation. Here, key variables were investigated that influence siRNA loading into porous silicon nanoparticles. The effect of modifying the surface of porous silicon nanoparticles with various amino-functional molecules as well as the effects of salt and chaotropic agents in facilitating siRNA loading was examined. Maximum siRNA loading of 413 μg/(mg of porous silicon nanoparticles) was found when the nanoparticles were modified by a fourth generation polyamidoamine dendrimer. Low concentrations of urea or salt increased loading capacity: an increase in RNA loading by 19% at a concentration of 0.05 M NaCl or 21% at a concentration of 0.25 M urea was observed when compared to loading in water. Lastly, it was demonstrated that dendrimer-functionalized nanocarriers are able to deliver siRNA against ELOVL5, a target for the treatment of advanced prostate cancer.

Unprecedented Intramolecular Association-Induced Fluorescence in Tryptophan-Conjugated Peptidomimetics

We report herewith tryptophan (Trp)-conjugated peptidomimetics that show intramolecular through-space association between the Trp units. Our investigation revealed that the proximal placement of Trp can lead to the emergence of a new and unanticipated fluorescent entity constituting a Trp-Trp dimer. Proton-induced modulation of fluorescence is a consequence of this work. Investigations with control compounds unequivocally revealed that the fluorescence property is not originated from the localized excited state but from the unprecedented Trp-Trp intramolecular dimer in the ground state itself. The present findings will initiate the biophysical scientists to have a relook at the fluorescence properties of Trp-containing proteins.

Influence of disease duration and socioeconomic factors on the prevalence of infection and hospitalization in rheumatoid arthritis: KRAC study

AIM

The use of healthcare resources by rheumatoid arthritis (RA) patients can be related to the presence of disease, comorbid conditions, use of steroids, and the combined use of immunosuppressants. This study evaluated the risk factors associated with infection and hospitalization in RA.

METHODS

This multicenter, cross-sectional study enrolled 3247 RA subjects fulfilling the 2010 American College of Rheumatology/European League Against Rheumatism criteria to examine the prevalence of hospitalization and episodes of documentable non-tubercular infections as a part of the "Karnataka rheumatoid arthritis comorbidity" study (KRAC). The study included 2081 subjects and 1166 were excluded due to incomplete data. Demographic, clinical and treatment variables were collected, and the events related to infections and hospitalization were extracted from the medical records. Comparative analysis and multivariate logistic regression were performed.

RESULTS

Around 22% of the subjects had hospitalizations and 2.9% had infections. Infections were pertaining to dental (1.3%), urinary tract (1.6%) and candidiasis (0.2%). Skin- and soft tissue-related infections were found in 1.8% and 0.3% of patients, respectively. Increased need of hospitalization in RA patients was associated with advanced age (≥60 years), lower education, family income, and longer duration of RA. Presence of comorbidity, usage of three or more disease-modifying anti-rheumatic drugs (DMARDs) and family income influenced the likelihood of infection. Dental infections were less likely in working subjects and more likely in patients with increased disease duration, higher family income, comorbidities and those between the age group 40-59 years. Urinary tract infection was associated with DMARD usage.

CONCLUSION

Patient-specific risk factors should be considered to improve treatment strategies and to reduce the risk of infection and hospitalization in RA patients.

Prevalence and Clinical Use of Anti-Thyroid Antibodies in RA Patients: A Prospective Case-Control Study

AIM

To evaluate the prevalence of anti-thyroid antibodies in a cohort of rheumatoid arthritis (RA) patients from south India and their clinical use.

METHODS

A cross-sectional epidemiological study was conducted including 1217 patients aged more than 14 years with fever and thrombocytopenia admitted in the medical wards from October 2013 to September 2014. Detailed clinical examination and routine investigations were done; specific investigations like blood culture, widal test, antigen test for malaria, IgM ELISA leptospira, IgM ELISA dengue, bone marrow aspiration/biopsy etc. were done as and when indicated. The data are presented as percentage and numbers. Rates and ratios are computedThe prospective case-control study, conducted for 3 consecutive months in a tertiary care hospital based in India, evaluated 103 RA patients (active group) and 36 age-matched healthy controls without the disease. Both the control and active groups were compared for thyroid autoantibodies, and the clinical evaluation included assessment of swollen joint counts (SJC), tender joint counts (TJC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), pain scale, disease activity score (DAS), rheumatoid factor (RF), anti-nuclear antibody (ANA) and anti-cyclic citrullinated peptide (anti-CCP). The active group subjects were further subdivided into RA patients with and without hypothyroidism, and were compared for normal and abnormal levels of thyroid autoantibodies and the variations were statistically analysed.

RESULTS

The corresponding mean age of the subjects belonging to the active and control groups were 47.09±11.29 and 41.03±11, with a female to male ratio of 1:0.12 and 1:0.29 respectively. Among the various thyroid autoantibodies compared between the active and control groups, a significant correlation (P=0.00936) was observed for anti-TTG antibodies. Also, the study has noted a significantly elevated level of anti-TPO antibodies in RA patients with hypothyroidism compared to the group without hypothyroidism (P=0.0074).

CONCLUSION

A significantly increased level of anti-TPO antibodies was noted in RA patients with hypothyroidism.

Comorbidities and related factors in rheumatoid arthritis patients of south India- Karnataka Rheumatoid Arthritis Comorbidity (KRAC) study

The aim was to study the prevalence of comorbidities in rheumatoid arthritis (RA) patients in everyday clinical practice and their association with disease-specific and demographic factors. The multi-center study recruited 3,247 (at 14 centers, and 265) were excluded due to incomplete data. The number of subjects considered for the analysis was 2982. The mean (±standard deviation) age was 48.98±12.64 years and the male-to-female ratio was 1:5. The data was collected based on a pre-structured pro forma by trained clinical research associates through interview and verification of charts and reports available in the patient records. The following comorbidities were studied: cardiovascular disease, hypertension, diabetes mellitus, hypercholesterolemia, thyroid disease, psychiatric diseases like depression, and pulmonary disease. Hypertension (20.7%), diabetes mellitus (14.4%) and thyroid disease (18.3%) were the most prevalent comorbidities. Hypercholesterolemia (5.3%), pulmonary diseases (2.1%), cardiovascular diseases (0.2%) and depression (0.03%) were prevalent in ≤5% of the study population. The overall presence of comorbidity increased with age and reduced with the duration of illness prior (DOIP). The age, gender, and DOIP differed significantly between groups with and without hypercholesterolemia. Females had a statistically increased prevalence of thyroid disease. The prevalence of comorbidities in RA patients from south India is around 40% and the incidence of comorbidity increased with age. As per the literature evidence, the prevalence in the current study subjects was higher when compared to prevalence of similar diseases occurring in the general south Indian population.