Control of Photoisomerization Kinetics via Multistage Switching in Bimetallic Ru(II)-Terpyridine Complexes.

In this study, we carried out detailed experimental and theoretical investigation on photophysical, electrochemical, and photoisomerization behaviors of a new array of luminescent binuclear Ru(II) complexes derived from a phenylene-vinylene-substituted terpyridyl ligand possessing RT lifetimes within 60.3-410.5 ns. The complexes experienced trans-to-cis isomerization in MeCN on irradiation with visible light, accompanied by significant changes in their absorption and emission spectral profiles. The reverse cis-to-trans process is also possible with the use of ultraviolet (UV) light. On conversion from trans to cis isomers, the emission intensity increases substantially, while for the reverse process, luminescence quenching occurs. Thus, "off-on" and "on-off" emission switching is facilitated upon treatment with visible and UV light alternatively. By the use of chemical oxidants (ceric ammonium nitrate and potassium permanganate) and reductants (metallic sodium) as well as light of appropriate wavelengths, multistate switching phenomena involving reversible oxidation-reduction and trans-cis isomerization have been achieved. Interestingly, the rate of this multistate photoswitching process becomes much faster compared to only two-state trans-cis isomerization of these complexes. Density functional theory (DFT) and time-dependent-DFT (TD-DFT) calculations are also performed to obtain a clear picture of the electronic environment of the complexes and also for the appropriate assignment of absorption and emission spectral bands.

Luminescent Ruthenium-Terpyridine Complexes Coupled with Stilbene-Appended Naphthalene, Anthracene, and Pyrene Motifs Demonstrate Fluoride Ion Sensing and Reversible Trans-Cis Photoisomerization.

A new family of luminescent heteroleptic Ru(II)-terpyridine complexes coupled with stilbene-appended naphthalene, anthracene, and pyrene motifs is reported. Each of the complexes features moderately intense emission at room temperature having a lifetime of 16.7 ns for naphthalene and 11.4 ns for anthracene, while a substantially elevated lifetime of 8.3 µs was observed for the pyrene derivative. All the three complexes display a reversible couple in the positive potential window due to Ru2+/Ru3+ oxidation but multiple reversible and/or quasi-reversible peaks in the negative potential domain because of the reduction of the terpyridine moieties. All the complexes selectively sense F- among the studied anions via the intermediary of different noncovalent interactions. The interaction event is monitored through absorption, emission, and 1H and 19F NMR spectroscopy. Additionally, upon utilizing the stilbene motif, reversible trans-cis isomerization of the complexes has been undertaken upon alternate treatment of visible and UV light so that the complexes can act as potential photomolecular switches. We also carried out the anion sensing characterization of the cis form of the complexes. Theoretical calculation employing density functional theory is also executed for a selective complex (naphthalene derivative) to elucidate different noncovalent interactions that are operative during the complex-fluoride interplay.

Direct Membrane Penetration and Cytosolic Delivery of Nanoparticles via Electrostatically Bound Amphiphiles.

Nanoparticles usually enter cells through energy-dependent endocytosis that involves their cytosolic entry via biomembrane-coated endosomes. In contrast, direct translocation of nanoparticles with straight access to cytosol/subcellular components without any membrane coating is limited to very selective conditions/approaches. Here we show that nanoparticles can switch from energy-dependent endocytosis to energy-independent direct membrane penetration once an amphiphile is electrostatically bound to their surface. Compared to endocytotic uptake, this direct cell translocation is faster and nanoparticles are distributed inside the cytosol without any lysosomal trafficking. We found that this direct cell translocation option is sensitive to the charges of both the nanoparticles and the amphiphile. We propose that an electrostatically bound amphiphile induces temporary opening of the cell membrane, which allows direct cell translocation of nanoparticles. This approach can be adapted for efficient subcellular targeting of nanoparticles and nanoparticle-based drug delivery application, bypassing the endosomal trapping and lysosomal degradation.

Self-Assembly of Unusually Stable Thermotropic Network Phases by Cellobiose-Based Guerbet Glycolipids.

Bicontinuous thermotropic liquid crystal (LC) materials, e.g., double gyroid (DG) phases, have garnered significant attention due to the potential utility of their 3D network structures in wide-ranging applications. However, the utility of these materials is significantly constrained by the lack of robust molecular design rules for shape-filling amphiphiles that spontaneously adopt the saddle curvatures required to access these useful supramolecular assemblies. Toward this aim, we synthesized anomerically pure Guerbet-type glycolipids bearing cellobiose head groups and branched alkyl tails and studied their thermotropic LC self-assembly. Using a combination of differential scanning calorimetry, polarized optical microscopy, and small-angle X-ray scattering, our studies demonstrate that Guerbet cellobiosides exhibit a strong propensity to self-assemble into DG morphologies over wide thermotropic phase windows. The stabilities of these assemblies sensitively depend on the branched alkyl tail structure and the anomeric configuration of the glycolipid in a previously unrecognized manner. Complementary molecular simulations furnish detailed insights into the observed self-assembly characteristics, thus unveiling molecular motifs that foster network phase self-assembly that will enable future designs and applications of network LC materials.

Influences of Both N,N,N- and N,N,C-Coordination Modes of Tolyl-terpyridine on the Photophysical Properties of Cyclometalated Ru(II) Complexes: Combined Experimental and Theoretical Investigations on Acid/Base-Dependent Reversible Cyclometalation.

With the goal of developing a new strategy for the synthesis of luminescent Ru(II) complexes, we have prepared herein a new set of bis-tridentate complexes of the type [(py-bpy-Ph-X)Ru(tpy-PhCH3)]ClO4 (X = -CH3, -CH2Br, and -CHO) incorporating both non-cyclometalated and cyclometalated coordination motifs of two isomeric forms of methylphenyl-terpyridine (tpy-PhCH3). Thorough characterization of the synthesized complexes is carried out using standard analytical tools and single crystal X-ray diffraction. Detailed investigations on their photophysical and electrochemical behaviors are carried out in MeCN. The presence of a carbanionic center in the cyclometalating unit increases the absorption spectral window of the complexes into a longer-wavelength region. The complexes also exhibit room-temperature luminescence in the NIR domain with enhanced excited-state lifetimes (up to 20.1 ns) compared to their non-cyclometalated counterpart, [Ru(tpy-PhCH3)2]2+. In the presence of acid, the non-coordinated nitrogen atom in the secondary coordination sphere of the complexes allows fine-tuning of the absorption and emission spectral properties. Excess acid induces de-coordination of the Ru-C bond, which is signaled by a remarkable alteration of their spectral profiles. Cleavage of the Ru-C bond is also possible upon treating the acidified solution of the complexes with visible light. Restoration of the Ru-C bond is again feasible upon treating the solution with base at an elevated temperature (∼70 °C). In essence, "on-off" and "off-on" switching of emission is facilitated upon alternating treatment of the Ru(II) complexes with acid, base, and temperature. DFT and TD-DFT calculations are also performed for assignments of the spectral bands as well as to understand structural changes associated with the switching behaviors of the complexes.

Evaluation of Mitral-Aortic Flow Velocity Integral Ratio as a Tool to Differentiate Between Severe and Nonsevere Mitral Regurgitation.

OBJECTIVES: To evaluate mitral-aortic flow velocity integral ratio (MAVIR) as an echocardiographic tool to differentiate between severe and nonsevere mitral regurgitation (MR), compared with regurgitant volume (RVol) and effective regurgitant orifice area (EROA), with subgroup analysis in patients with calcific mitral valve, both by transthoracic (TTE) and transesophageal (TEE) echocardiography. Also, whether MAVIR can be used as a screening tool for severe MR. DESIGN: Prospective, cross-sectional, observational. SETTING: Cardiac operating room of a tertiary-care hospital. PARTICIPANTS: One hundred adult patients with chronic mitral regurgitation with at least mild MR by two-dimensional Doppler and with absence of mitral stenosis, aortic valve disease, and rhythm other than sinus scheduled for cardiac surgery. The subgroup (n = 24) consisted specifically of patients with a calcific mitral valve. INTERVENTIONS: Preinduction TTE and postinduction TEE in the operating room. MEASUREMENTS AND RESULTS: MAVIR, RVol, and EROA were measured in all patients both by TTE and TEE. Cohen's kappa statistics was employed to quantify concordance among RVol, EROA, and MAVIR. Diagnostic indices of MAVIR toward diagnosis of severe MR also were quantified. The results showed a strong agreement, in differentiating severe from nonsevere MR, between MAVIR and both RVol and EROA in the whole cohort (n = 100) and the subgroup (n = 24), both by TTE and TEE. Diagnostic indices were high for MAVIR compared with RVol and EROA in detecting severe MR, both by TTE and TEE. CONCLUSION: MAVIR may be used as an echocardiographic tool to differentiate between severe and nonsevere MR, even in patients with calcific valves. It also can be used to screen patients for severe MR.

Comparison Among Ultrasound-Guided Thoracic Paravertebral Block, Erector Spinae Plane Block and Serratus Anterior Plane Block for Analgesia in Thoracotomy for Lung Surgery.

BACKGROUND: To compare the analgesic efficacy and safety of preoperative, single-shot ultrasound-guided thoracic paravertebral block (TPVB), erector spinae plane block (ESB), and serratus anterior plane block (SAPB) in thoracotomy pain. DESIGN: A prospective, randomized study. SETTING: The cardiothoracic operating room and intensive care unit of a tertiary-care hospital in India. PARTICIPANTS: Ninety adult patients scheduled to undergo posterolateral thoracotomy for lung surgery under general anesthesia were recruited and randomized into 3 equal groups. INTERVENTIONS: Preoperatively, the patients received ultrasound-guided, single-shot nerve blocks within their respective groups, as follows: Erector spinae plane block in the ESB group, Thoracic paravertebral block in the TPVB group, and Serratus anterior plane block in the SAPB group. MEASUREMENTS AND RESULTS: The primary outcome measure, the visual analog scale (VAS) score, was recorded postoperatively in the intensive care unit at 0, 3, 6, 12, and 24 hours. The secondary outcome measures were the time to first rescue analgesic, total rescue opioid dose used, patient satisfaction at 24 hours, success of one-time attempt, and occurrence of adverse events. Data were statistically analyzed and a significant difference was found in the VAS score at all time points, the time to rescue analgesic and total opioid dosage, and patient satisfaction level (p < 0.05) among the groups with only 1 incidence of hypotension in the TPVB group. From post hoc analysis, ESB was found to have better analgesic efficacy compared with TPVB and SAPB. Serratus anterior plane block was found to be least efficacious and shortest acting among the three. CONCLUSION: The nerve blocks in decreasing order of analgesic efficacy in relieving post-thoracotomy pain would be ESB, TPVB, and SAPB.

Understanding the role of non-Watson-Crick base pairs in DNA-protein recognition: Structural and energetic aspects using crystallographic database analysis and quantum chemical calculation.

Specific recognition of DNA base sequences by proteins is vital for life-cycles of all organisms. In a large number of crystal structures of protein-DNA complexes, DNA conformation significantly deviates from the canonical B-DNA structure. A key question is whether such alternate conformations exist prior to protein binding and one is selected for complexation or the structure observed is induced by protein binding. Non-canonical base pairs, such as Hoogsteen base pairs, are often observed in crystal structures of protein-DNA complexes. We decided to explore whether the occurrence of such non-canonical base pairs in protein-DNA complexes is induced by the protein or is selected from pre-existing conformations. Detailed quantum chemical calculations with dispersion-corrected density functional theory (DFT-D) indicated that most of the non-canonical base pairs with DNA bases are stable even in the absence of the interacting amino acids. However, the G:G Hoogsteen base pair, which also appears in the telomere structure, appears to be unstable in the absence of other stabilizing agents, such as positively charged amino acids. Thus, the stability of many of the non-canonical base pair containing duplexes may be close to the canonical B-DNA structure and hence energetically accessible in the ground state; suggesting that the selection from pre-existing conformations may be an important mechanism for observed non-canonical base pairs in protein-DNA complexes.

An Untargeted LC-MS based approach for identification of altered metabolites in blood plasma of rheumatic heart disease patients.

Rheumatic heart disease (RHD) is often considered as a disease of developing countries and India is the home of about 40% of RHD patients. Environment seems to play a major role in its causation. Since gene environment interactions can lead to alterations of various metabolic pathways, identification of altered metabolites can help in understanding the various pathways leading to RHD. Blood plasma samples from 51 RHD and 49 healthy controls were collected for the study. Untargeted metabolomics approach was used to identify the metabolites that are altered in RHD patients. Data showed 25 altered metabolites among RHD patients. These altered metabolites were those involved in Purine, Glutamine, Glutamate, Pyrimidine, Arginine, Proline and Linoleic metabolism. Thus, the present study illuminates metabolic alterations among RHD patients which can help in determining the potential therapeutic targets.

Tuning of photo-redox behaviours and thermodynamic and kinetic aspects of intercomponent energy transfer in trimetallic complexes of Ru(II) and Os(II) by exploiting their second coordination sphere.

This paper deals with a thorough investigation of pH-induced tuning of the ground and excited state photophysical as well as electrochemical behaviours of two series of our recently reported homo- and heterotrimetallic complexes of the type [(bpy)2Ru(d-HIm-t)M(t-HIm-d)Ru(bpy)2]6+ and [(bpy)2Os(d-HIm-t)M(t-HIm-d)Os(bpy)2]6+ (M = RuII and OsII) derived from a heteroditopic bpy-tpy (d-HIm-t) type bridging ligand through the exploitation of their second coordination sphere. A small bathochromic shift of the absorption and emission spectral band along with substantial alteration of emission intensity and lifetime of the triads is noted upon deprotonation of the NH motifs at elevated pH values. The lowering of the half wave potential of a M3+/M2+ couple is also observed upon removal of the NH protons. Both ground and excited state pKa values of the triads are estimated from their absorption/emission versus pH spectral profiles. In addition, the variation of the free energy change (ΔG) and the rate of intercomponent energy transfer (ken) in the triads upon stepwise deprotonation of the NH motifs are also addressed in the present study.

Familial dilated cardiomyopathy with RBM20 mutation in an Indian patient: a case report.

BACKGROUND: Dilated cardiomyopathy (DCM) is a disease of the heart muscle characterized by ventricular dilation and a left ventricular ejection fraction of less than 40%. Unlike hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC), DCM-causing mutations are present in a large number of genes. In the present study, we report a case of the early age of onset of DCM associated with a pathogenic variant in the RBM20 gene in a patient from India. CASE PRESENTATION: A 19-year-old Indian male diagnosed with DCM was suggested for heart transplantation. His ECG showed LBBB and echocardiography showed an ejection fraction of 14%. He had a sudden cardiac death. A detailed family history revealed it to be a case of familial DCM. Genetic screening identified the c.1900C>T variant in the RBM20 gene which led to a missense variant of amino acid 634 (p.Arg634Trp). CONCLUSION: To the best of our knowledge, the variant p.Arg634Trp has been earlier reported in the Western population, but this is the first case of p.Arg634Trp in an Indian patient. The variant has been reported to be pathogenic at an early age of onset; therefore, close clinical follow-up should be done for the family members caring for the variant.

pH-Responsive colorimetric, emission and redox switches based on Ru(ii)-terpyridine complexes.

We have undertaken a thorough investigation on pH-responsive optical and redox switching behaviors of our recently reported trans form of bis-tridentate Ru(ii) luminophores, [(H2pbbzim)Ru(tpy-pvp-X)]2+ where X = H, Me, Cl, NO2, and Ph. The complexes possess two benzimidazole protons in their second coordination sphere, which became acidic upon coordinating influence of Ru2+ and could be successively deprotonated with the increase of pH. The effect of pH on photophysical and electrochemical behaviours of the complexes was thoroughly studied. Substantial quenching of emission together with the red-shift of both absorption (color change) and emission bands is noticed for all complexes upon dissociation of NH protons. Absorption vs. pH data were employed for determination of ground-state pKa values, while excited-state pKa (pKa*) values were estimated by employing the Förster cycle based equation. The electronic nature of X induces a small but finite effect on the pKa values and a linear correlation is found by plotting pKavs. Hammett σp parameters of X. Proton-coupled electrochemical behaviours were investigated within the pH range of 1-10. From the E1/2vs. pH plot, acid dissociation constants in different protonation states of the complexes were estimated in both Ru2+ and Ru3+ states. Compared with their protonated forms which exhibit reversible oxidation within 0.91-0.95 V, the oxidation potential of the doubly deprotonated forms shifted remarkably to the cathodic region (0.61-0.66 V). In essence, the present complexes act as potential pH-responsive colorimetric, emission and redox switches.

DNA base sequence specificity through partial intercalation: DFT-D based energy analysis of molecular dynamics snapshots.

It had been observed that in some DNA-binding proteins, hydrophobic amino acid side-chains intercalate between two base pairs of the DNA, often leading to curvature or kink. Some of these proteins pre-dominantly interact through the minor groove and are often described as not having strong sequence preference. In contrast, lac-repressor binds to DNA with strong sequence specificity, also interacts with the minor groove of its operator by partially intercalating two Leucine side-chains between two CG base pairs, in addition to its interaction with the major groove base atoms. The role of this interaction in the operator recognition has not been fully elucidated. We have done extensive quantum chemical calculations, from molecular dynamics derived snapshots, using dispersion-corrected density functional theory to show that this unstacking is energetically slightly unfavorable. However, among all the base-amino acid pairs studied, the CG/CG-Leucine pair, the natural sequence, is among the most stable ones. The bending of the DNA resulting from this intercalation is important for aligning the major dimeric protein and the DNA interfaces. Thus, the sacrifice of modest binding energy enhances the sequence-specificity. Given many prokaryotic repressors belong to the lac repressor family, this could be a general mechanism for augmenting sequence specificity.

Fabrication of nanoparticles from a synthesized peptide amphiphile as a versatile therapeutic cargo for high antiproliferative activity in tumor cells.

Nanoparticles with encapsulated small molecules have attained vital importance in anticancer research. Peptide-based nanoparticles show their versatility in drug delivery due to their excellent biocompatibility and nontoxic nature. We demonstrate here the design and fabrication of peptide-based nanoparticles as dual-therapeutic cargo for the controlled release of hydrophilic 5-Fluorouracil (5Fu) and hydrophobic camptothecin (CPT), simultaneously. The covalent conjugation of 5Fu with the peptide, through a stimuli-responsive linker, provided better control over the release of 5Fu and dramatically reduced the possibility of leaching of the small molecule. As anticipated, the peptide-5Fu nanoparticles were efficient to encapsulate a second chemotherapeutic molecule CPT in its hydrophobic region. The stimuli-responsive release of 5Fu was carefully monitored by HPLC, NMR, and UV-visible spectroscopy. On the other hand, the release of the hydrophobic drug CPT from the nanoparticles was determined to be in a diffusion-controlled fashion. Assessment of performance in human cervical HeLa cell lines demonstrated the peptide-drug nanoparticles to be highly nontoxic. Whereas, the simultaneous release of the two antitumor agents, in a controlled manner, resulting in rapid antiproliferation of the tumor cells.

A rhodamine based biocompatible chemosensor for Al3+, Cr3+ and Fe3+ ions: extraordinary fluorescence enhancement and a precursor for future chemosensors.

A rhodamine based chemosensor, 3-(((2-(3',6'-bis(ethylamino)-2',7'-dimethyl-3-oxospiro[isoindoline-1,9'-xanthen]-2-yl)ethyl)imino)methyl)-2-hydroxy-5-methylbenzaldehyde (HL-CHO), has been developed for the detection of Al3+, Cr3+ and Fe3+ ions. The absorbance of HL-CHO at 528 nm increases significantly in HEPES buffer in methanol : water (9 : 1, v/v) (pH 7.4) in the presence of Al3+, Cr3+ and Fe3+ ions with the alteration of solution color from colorless to pink. The fluorescence intensity of the probe at 550 nm enhances by 1465, 588 and 800 fold in the presence of Al3+, Cr3+ and Fe3+ ions, respectively. To the best of our knowledge, this huge increase in fluorescence intensity with Al3+ and Cr3+ has not been observed for other rhodamine based chemosensing systems. The weak fluorescence and no coloration of the probe are due to the existence of a spirolactam ring. The trivalent cations induce the opening of the spirolactam ring and consequently change the color and the fluorescence intensity followed by the 1 : 1 complex formation with HL-CHO which are evident from Job's analysis, ESI mass spectral analysis and elemental analysis. The quantum yield and lifetime of HL-CHO have increased considerably in the presence of the trivalent cations. The high sensitivity of the probe towards all the cations is evident from the nM order of LOD values. This has been used in living cell imaging studies with the human neuroblastoma SH-SY5Y cell line. Having appended -CHO groups for Schiff-base condensation with other amines, HL-CHO could be a potential precursor for future chemosensors.

Loss of function mutation in the P2X7, a ligand-gated ion channel gene associated with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is an inherited heart failure condition, mostly found to have genetic abnormalities, and is a leading cause of sudden death in young adults. Whole exome sequencing should be given consideration as a molecular diagnostic tool to identify disease-causing mutation/s. In this study, a HCM family with multiple affected members having history of sudden death were subjected to exome sequencing along with unaffected members. Quality passed variants obtained were filtered for rarity (MAF > 0.5%), evolutionary conservation, pathogenic prediction, and segregation in affected members after removing shared variants present in unaffected members. Only one non-synonymous mutation (p. Glu186Lys or E186K) in exon 6 of P2X7 gene segregated in HCM-affected individuals which was absent in unaffected family members and 100 clinically evaluated controls. The site of the mutation is highly conserved and led to complete loss of function which is in close vicinity to ATP-binding site-forming residues, affecting ATP binding, channel gating, or both. Mutations in candidate genes which were not segregated define clinical heterogeneity within affected members. P2X7 gene is highly expressed in the heart and shows direct interaction with major candidate genes for HCM. Our results reveal a significant putative HCM causative gene, P2X7, for the first time and show that germ-line mutations in P2X7 may cause a defective phenotype, suggesting purinergic receptor involvement in heart failure mediated through arrhythmias which need further investigations to be targeted for therapeutic interventions.

Development of a photoresponsive chitosan conjugated prodrug nano-carrier for controlled delivery of antitumor drug 5-fluorouracil.

Controlled drug delivery offers improved therapeutic efficacy of the drugs while minimizing side effects. Biocompatible polymers and nanomaterials have emerged as effective carriers for the controlled delivery of drugs. We have synthesized a prodrug of 5-fluorouracil (5FU) covalently conjugated to low molecular weight chitosan (LMWC) via a photocleavable linker. The conjugate was designed to be cleaved under 365 nm UV-A radiations, which is regarded as relatively safe for the cells and release 5FU in a dose-dependent manner. The conjugate showed enhanced water solubility compared to LMWC and forms hydrogel and DMSO gel. The conjugate polymer was also fabricated into nanoparticles by ionic gelation technique. The size of the nanoparticles was found to be in the range 70-90 nm, thus should have the ability to penetrate into living cells. In vitro release study of 5FU from the conjugate showed controlled release of the antitumor drug over time. The synthesized nanoparticles and the gel, therefore, could be a good model for controlled release of antitumor drugs.

Is elevated blood glucose a marker of occult tissue hypoperfusion in off-pump coronary artery bypass grafting?

CONTEXT: Hyperglycemia has been found to occur during myocardial infarction and cardiac surgery even in nondiabetic patients. These being essentially stressful processes associated with hypoperfusion, we decided to find a possible relationship between the occurrence of global tissue hypoperfusion (GTH) and elevated blood glucose level in adult nondiabetic patients undergoing elective off-pump coronary artery bypass grafting (CABG). AIMS: This study aims to observe for the occurrence of global tissue hypoperfusion and its effect on blood glucose level and whether raised blood glucose level can be used as a marker for GTH. DESIGN: Prospective, observational study. SETTINGS: Cardiothoracic operation theater and intensive care unit of a tertiary care teaching hospital. MATERIALS AND METHODS: The occurrence of global tissue hypoperfusion were detected with the help of combined markers of mixed venous oxygen saturation and arterial lactate level at various perioperative study points together with arterial blood glucose level. Blood glucose level compared between the patients with and without GTH. STATISTICAL ANALYSIS USED: Numerical variables were compared between groups by Student's t-test and categorical variables by Fisher's exact test. Two-tailed P ≤ 0.05 was considered for statistically significant. RESULTS: The incidence of GTH was 67%. Blood glucose level was raised in patients with GTH at some study time points but with poor sensitivity and specificity values. CONCLUSIONS: Global tissue hypoperfusion is a common occurrence in even nondiabetic patients undergoing elective off-pump CABG. A relationship exists between rise in blood glucose level and global tissue hypoperfusion in such patients, although it cannot be viewed as marker of the same.

Familial Hypertrophic Cardiomyopathy - Identification of cause and risk stratification through exome sequencing.

BACKGROUND: Hypertrophic Cardiomyopathy (HCM) with variable clinical presentations and heterogeneity is the common cause of sudden cardiac death. Genetic diagnosis is challenging in these complex diseases but exome sequencing as a genetic diagnostic tool provides explainable results. METHODS: In a familial Hypertrophic Cardiomyopathy with multigenerational inheritance with apparent phenotype, had a history of sudden death and severe arrhythmia followed by implantation of Implantable cardioverter defibrillator (ICD). Exome sequencing (100×) trailed by effective filtering steps for exome variants on the basis of different parameters, segregated variants are prioritized for the disease and further clinical relevance are evaluated for the variants. RESULTS: A rare causal variant in troponin-T gene (TNNT2, NM_000364.3;c.274C > T;p.Arg92Trp) is identified, shared by only affected members, absent in unaffected members and also in 200 unrelated control chromosomes. TNNT2 mutation act as a driver mutation but mutations in other disease-related genes, KCNMB1, LPL, APOE and other biochemical factors provides risk stratification within affected family members. CONCLUSION: This study contributes to the role of "rare variants" in complex disease phenotypes and heterogeneity within family and the necessity of whole exome targeted approaches in complex cardiomyopathy, which are known to harbor private mutations.

Burden among Parkinson's disease care givers for a community based study from India.

Aim was to analyze predictors of burden among primary caregivers (CGs) of Indian Parkinson's disease (PD) patients. 150 PD patients were administered using Unified Parkinson's Disease Rating Scale (UPDRS), Hoehn and Yahr Scale (H&Y), Montgomery Asberg Depression Rating Score (MADRS) and Mini Mental State Examination (MMSE) in this cross-sectional evaluation study. CG burden was assessed by Caregiver's Burden Scale (CBS), Hospital Anxiety and Depression Scale (HADS), SF-36 and 20-item Burden Assessment Schedule (BAS). Linear regression methods were used to evaluate factors contributing to burden and stress. Mean age of CG was 50.38±16.04 (range: 25-83 yrs). Marital status of CGs was noted to have significant relationship with CBS score (F=9.525, P<0.0001). Siblings (brother/sister) reported the highest CBS score while the wives reported the least. Correlations were strong between CBS and HADS anxiety (r=0.228, P=0.0048) and HADS depression (r=0.2172, P=0.0076). High correlations were found in caregiving duration, patients' stage of illness and motor disability among all the scales (CBS, HADS, SF36) determined. Step-wise regression analysis showed UPDRS (beta=1.364-0.202 ranging among all scales) and H&Y stages (beta=2.786-7.257) to have the strongest influence on CGs. CGs of patients with depression (MADRS: P=0.007 (SF36 mental) and dementia (MMSE: P=0.01) experienced greater stress. Social and financial status was disrupted in ~60% to 80% of the CGs. Motor imbalances with disability of PD patients and severity of disease are the main factors contributing to burden and stress in CGs.