Isolated left ventricular non-compaction: Clinical characterisation of a teenage male.

Isolated Left Ventricular Non-compaction (LVNC) is a type of cardiomyopathy that usually has a genetic origin. Its diagnosis is based on finding such as deep intertrabecular recesses or sinusoids and ventricular trabeculations communicating with the left ventricular cavity. LVNC was first clinically recognised almost four decades ago, yet its diagnostic and management challenges persist. In this report, we present the case of an 18-year-old boy, who presented at the National Institute of Cardiovascular Diseases, Karachi, in March 2023, with complaints of dizziness, pedal oedema, and shortness of breath. Echocardiography revealed signs suggestive of LVNC, which were confirmed conclusively on Cardiovascular Magnetic Resonance (CMR) (NC/C ratio>2.4). The patient underwent implantable cardioverter defibrillator (ICD) placement, was discharged after a smooth post-procedure recovery, and is doing well on follow-ups. Hence, ICD and guideline-directed medical therapy as a combination have turned out to have satisfactory outcomes in decreasing morbidity and providing mortality benefits for such patients.

Cultural hierarchies in health: Does inherited sociocultural position (biraderi) shape diet and nutrition among British Pakistani children? Protocol for a mixed-methods study.

This study aims to explore links between biraderi-a form of identity-based social grouping and stratification which cuts across religions among South Asians-and infant and child nutrition among British Pakistanis using data from the Born in Bradford cohort study. The study will entail a mixed-methods approach to (i) develop an operational framework of biraderi for epidemiologic analyses and apply it to longitudinal data from the Born in Bradford cohort study, (ii) quantify and describe child nutrition and dietary patterns for biraderi sub-groups, and (iii) investigate whether known mechanisms of identity-based segregation, graded inequality, and network effects operate through diet and nutrition in the UK. Using Krieger's ecosocial theory as an integrative framework we will (iv) re-conceptualise and interpret the role of biraderi / caste in the social construction and embodied experience of how infants and children eat in the UK. Following a literature review on biraderi and health, we will convene and consult a lay consultation group in Bradford through focus groups and academic experts through a Delphi study to guide planning, implementation, interpretation and dissemination of our secondary data analysis. In addition to being the first study to look at biraderi-based nutritional inequalities in the UK, our study is innovative in that we will formally involve experts and users in the design and interpretation of our quantitative analyses. Findings will be applicable in any part of the world where children experience disadvantage linked to sociocultural hierarchy and identity. Our findings will be of particular use in (i) identifying women and children at particular risk of suboptimal breastfeeding practices, poor complementary feeding, and unhealthy diets in primary school in the UK, and (ii) elucidating the sociocultural pathways through which inequalities in population health nutrition outcomes are expressed.

Inhomogeneous energy transfer dynamics from iron-stress-induced protein A to photosystem I.

Cyanobacteria respond to iron limitation by producing the pigment-protein complex IsiA, forming rings associated with photosystem I (PSI). Initially considered a chlorophyll-storage protein, IsiA is known to act as an auxiliary light-harvesting antenna of PSI, increasing its absorption cross-section and reducing the need for iron-rich PSI core complexes. Spectroscopic studies have demonstrated efficient energy transfer from IsiA to PSI. Here we investigate the room-temperature excitation dynamics in isolated PSI-IsiA, PSI, IsiA monomer complexes and IsiA aggregates using two-dimensional electronic spectroscopy. Cross analyses of the data from these three samples allow us to resolve components of energy transfer between IsiA and PSI with lifetimes of 2-3 ps and around 20 ps. Structure-based Förster theory calculations predict a single major timescale of IsiA-PSI equilibration, that depends on multiple energy transfer routes between different IsiA subunits in the ring. Despite the experimentally observed lifetime heterogeneity, which is attributed to structural heterogeneity of the supercomplexes, IsiA is found to be a unique, highly efficient, membrane antenna complex in cyanobacteria.

Ultrafast Energy Transfer in a Diatom Photosystem II Supercomplex.

The light-harvesting complexes (LHCs) of diatoms, specifically fucoxanthin-Chl a/c binding proteins (FCPs), exhibit structural and functional diversity, as highlighted by recent structural studies of photosystem II-FCP (PSII-FCPII) supercomplexes from different diatom species. The excitation dynamics of PSII-FCPII supercomplexes isolated from the diatom Thalassiosira pseudonana was explored using time-resolved fluorescence spectroscopy and two-dimensional electronic spectroscopy at room temperature and 77 K. Energy transfer between FCPII and PSII occurred remarkably fast (<5 ps), emphasizing the efficiency of FCPII as a light-harvesting antenna. The presence of long-wavelength chlorophylls may further help concentrate excitations in the core complex and increase the efficiency of light harvesting. Structure-based calculations reveal remarkably strong excitonic couplings between chlorophylls in the FCP antenna and between FCP and the PSII core antenna that are the basis for the rapid energy transfer.

Effects of lipids on the rate-limiting steps in the dark-to-light transition of Photosystem II core complex of Thermostichus vulcanus.

In our earlier works, we have shown that the rate-limiting steps, associated with the dark-to-light transition of Photosystem II (PSII), reflecting the photochemical activity and structural dynamics of the reaction center complex, depend largely on the lipidic environment of the protein matrix. Using chlorophyll-a fluorescence transients (ChlF) elicited by single-turnover saturating flashes, it was shown that the half-waiting time (Δτ 1/2) between consecutive excitations, at which 50% of the fluorescence increment was reached, was considerably larger in isolated PSII complexes of Thermostichus (T.) vulcanus than in the native thylakoid membrane (TM). Further, it was shown that the addition of a TM lipid extract shortened Δτ 1/2 of isolated PSII, indicating that at least a fraction of the 'missing' lipid molecules, replaced by detergent molecules, caused the elongation of Δτ 1/2. Here, we performed systematic experiments to obtain information on the nature of TM lipids that are capable of decreasing Δτ 1/2. Our data show that while all lipid species shorten Δτ 1/2, the negatively charged lipid phosphatidylglycerol appears to be the most efficient species - suggesting its prominent role in determining the structural dynamics of PSII reaction center.

Inter-subunit energy transfer processes in a minimal plant photosystem II supercomplex.

Photosystem II (PSII) is an integral part of the photosynthesis machinery, in which several light-harvesting complexes rely on inter-complex excitonic energy transfer (EET) processes to channel energy to the reaction center. In this paper, we report on a direct observation of the inter-complex EET in a minimal PSII supercomplex from plants, containing the trimeric light-harvesting complex II (LHCII), the monomeric light-harvesting complex CP26, and the monomeric PSII core complex. Using two-dimensional (2D) electronic spectroscopy, we measure an inter-complex EET timescale of 50 picoseconds for excitations from the LHCII-CP26 peripheral antenna to the PSII core. The 2D electronic spectra also reveal that the transfer timescale is nearly constant over the pump spectrum of 600 to 700 nanometers. Structure-based calculations reveal the contribution of each antenna complex to the measured inter-complex EET time. These results provide a step in elucidating the full inter-complex energy transfer network of the PSII machinery.

Left atrial appendage thrombus with severe mitral stenosis: Responders and non-responders to anticoagulation.

INTRODUCTION AND OBJECTIVE: Mitral stenosis (MS) is one of the most frequently observed valvular heart lesions in developing countries and is due to different etiologies. The effects of anticoagulation in different types of left atrial appendage (LAA) are unknown. The current study aimed to determine the resolution of LAA thrombus on transesophageal echocardiography (TEE) after three months of optimal anticoagulation in patients with different types of LAA at baseline cardiac computed tomography of patients with severe MS. METHODS: This prospective cohort study observed the frequency of LAA thrombus resolution after three months of anticoagulation therapy in patients with severe MS. The response rate in different morphologies of LAA and locations was also assessed. Thrombus resolution after three months of warfarin therapy was assessed on repeat TEE. RESULTS: A total of 88 patients were included, mean age 37.95±11.87 years. Repeat TEE showed thrombus resolution in only 27.3% of patients. The rate of thrombus resolution was 8/12 (66.7%), 4/28 (14.3%), 8/36 (22.2%), and 4/12 (33.3%) for patients with cactus, cauliflower, chicken wing, and windsock LAA type, respectively. The resolution rate was 0/12 (0%), 4/44 (9.1%), and 20/32 (62.5%) for patients with thrombus in the base, body, and tip of the LAA, respectively. CONCLUSION: The cactus type of LAA morphology and thrombus at the LAA tip responded well to three months of anticoagulation, however, patients with thrombus in the LAA base and body and cauliflower and chicken wing morphology were non-responders and could benefit from early referral for surgical management.

Energy transfer from phycobilisomes to photosystem I at room temperature.

The phycobilisomes function as the primary light-harvesting antennae in cyanobacteria and red algae, effectively harvesting and transferring excitation energy to both photosystems. Here we investigate the direct energy transfer route from the phycobilisomes to photosystem I at room temperature in a mutant of the cyanobacterium Synechocystis sp. PCC 6803 that lacks photosystem II. The excitation dynamics are studied by picosecond time-resolved fluorescence measurements in combination with global and target analysis. Global analysis revealed several fast equilibration time scales and a decay of the equilibrated system with a time constant of ≈220 ps. From simultaneous target analysis of measurements with two different excitations of 400 nm (chlorophyll a) and 580 nm (phycobilisomes) a transfer rate of 42 ns-1 from the terminal emitter of the phycobilisome to photosystem I was estimated.