Determining a global mid-upper arm circumference cut-off to assess underweight in adults (men and non-pregnant women).

OBJECTIVE: To determine if a global mid-upper arm circumference (MUAC) cut-off can be established to classify underweight in adults (men and non-pregnant women). DESIGN: We conducted an individual participant data meta-analysis (IPDMA) to explore the sensitivity (SENS) and specificity (SPEC) of various MUAC cut-offs for identifying underweight among adults (defined as BMI < 18·5 kg/m2). Measures of diagnostic accuracy were determined every 0·5 cm across MUAC values from 19·0 to 26·5 cm. A bivariate random effects model was used to jointly estimate SENS and SPEC while accounting for heterogeneity between studies. Various subgroup analyses were performed. SETTING: Twenty datasets from Africa, South Asia, Southeast Asia, North America and South America were included. PARTICIPANTS: All eligible participants from the original datasets were included. RESULTS: The total sample size was 13 835. Mean age was 32·6 years and 65 % of participants were female. Mean MUAC was 25·7 cm, and 28 % of all participants had low BMI (<18·5 kg/m2). The area under the receiver operating characteristic curve for the pooled dataset was 0·91 (range across studies 0·61-0·98). Results showed that MUAC cut-offs in the range of ≤23·5 to ≤25·0 cm could serve as an appropriate screening indicator for underweight. CONCLUSIONS: MUAC is highly discriminatory in its ability to distinguish adults with BMI above and below 18·5 kg/m2. This IPDMA is the first step towards determining a global MUAC cut-off for adults. Validation studies are needed to determine whether the proposed MUAC cut-off of 24 cm is associated with poor functional outcomes.

Controlled micelle conjugation via charged peptide amphiphiles.

We report the first demonstration of nonionic detergent micelle conjugation and phase separation using purpose-synthesized, peptide amphiphiles, C10 -(Asp)5 and C10 -(Lys)5 . Clustering is achieved in two different ways. Micelles containing the negatively charged peptide amphiphile C10 -(Asp)5 are conjugated (a) via a water-soluble, penta-Lys mediator or (b) to micelles containing the C10 -(Lys)5 peptide amphiphile. Both routes lead to phase separation in the form of oil-rich globules visible in the light microscope. The hydrophobic nature of these regions leads to spontaneous partitioning of hydrophobic dyes into globules that were found to be stable for weeks to months. Extension of the conjugation mechanism to micelles containing a recently discovered, light-driven proton pump King Sejong 1-2 (KS1-2) demonstrates that a membrane protein may be concentrated using peptide amphiphiles while preserving its native conformation as determined by characteristic UV absorption. The potential utility of these peptide amphiphiles for biophysical and biomedical applications is discussed.

Protein conformational alterations induced by the retinal excited state in proton and sodium pumping rhodopsins.

Retinal proteins' biological activity is triggered by the retinal chromophore's light absorption, which initiates a photocycle. However, the mechanism by which retinal light excitation induces the protein's response is not completely understood. Recently, two new retinal proteins were discovered, namely, King Sejong 1-2 (KS1-2) and Nonlabens (Donghaeana) dokdonensis (DDR2), which exhibit H+ and Na+ pumping activities, respectively. To pinpoint whether protein conformation alterations can be achieved without light-induced retinal C13[double bond, length as m-dash]C14 double-bond isomerization, we utilized the hydroxylamine reaction, which cleaves the protonated Schiff base bond through which the retinal chromophore is covalently bound to the protein. The reaction is accelerated by light even though the cleavage is not a photochemical reaction. Therefore, the cleavage reaction may serve as a tool to detect protein conformation alterations. We discovered that in both KS1-2 and DDR2, the hydroxylamine reaction is light accelerated, even in artificial pigments derived from synthetic retinal in which the crucial C13[double bond, length as m-dash]C14 double-bond isomerization is prevented. Therefore, we propose that in both proteins the light-induced retinal charge redistribution taking place in the retinal excited state polarizes the protein, which, in turn, triggers protein conformation alterations. A further general possible application of the present finding is associated with other photoreceptor proteins having retinal or other non-retinal chromophores whose light excitation may affect the protein conformation.

Unleashing the power of porphyrin photosensitizers: Illuminating breakthroughs in photodynamic therapy.

This comprehensive review provides the current trends and recent developments of porphyrin-based photosensitizers. We discuss their evolution from first-generation to third-generation compounds, including cutting-edge nanoparticle-integrated derivatives, and explores their pivotal role in advancing photodynamic therapy (PDT) for enhanced cancer treatment. Integrating porphyrins with nanoparticles represents a promising avenue, offering improved selectivity, reduced toxicity, and heightened biocompatibility. By elucidating recent breakthroughs, innovative methodologies, and emerging applications, this review provides a panoramic snapshot of the dynamic field, addressing challenges and charting prospects. With a focus on harnessing reactive oxygen species (ROS) through light activation, PDT serves as a minimally invasive therapeutic approach. This article offers a valuable resource for researchers, clinicians, and PDT enthusiasts, highlighting the potential of porphyrin photosensitizers to improve the future of cancer therapy.

Retinal-Carotenoid Interactions in a Sodium-Ion-Pumping Rhodopsin: Implications on Oligomerization and Thermal Stability.

Microbial rhodopsin (also called retinal protein)-carotenoid conjugates represent a unique class of light-harvesting (LH) complexes, but their specific interactions and LH properties are not completely elucidated as only few rhodopsins are known to bind carotenoids. Here, we report a natural sodium-ion (Na+)-pumping Nonlabens (Donghaeana) dokdonensis rhodopsin (DDR2) binding with a carotenoid salinixanthin (Sal) to form a thermally stable rhodopsin-carotenoid complex. Different spectroscopic studies were employed to monitor the retinal-carotenoid interaction as well as the thermal stability of the protein, while size-exclusion chromatography (SEC) and homology modeling are performed to understand the protein oligomerization process. In analogy with that of another Na+-pumping protein Krokinobacter eikastus rhodopsin 2 (KR2), we propose that DDR2 (studied concentration range: 2 × 10-6 to 4 × 10-5 M) remains mainly as a pentamer at room temperature and neutral pH, while heating above 55 °C partially converted it into a thermally less stable oligomeric form of the protein. This process is affected by both the pH and concentration. At high concentrations (4 × 10-5 to 2 × 10-4 M), the protein adopts a pentamer form reflected in the excitonic circular dichroism (CD) spectrum. In the presence of Sal, the thermal stability of DDR2 is increased significantly, and the pigment is stable even at 85 °C. The results presented could have implications in designing stable rhodopsin-carotenoid antenna complexes.

Conjugation of native membranes via linear oligo-amines.

We report the first observation of an efficient, native membrane conjugation mechanism via positively charged, linear oligo-amines. Clustering of membrane fragments relies on electrostatic interactions between the net negative charge of the membranes and the positively charged, water-soluble mediators. This conjugation principle is demonstrated with two different bacterial membranes in which are embedded either the intrinsic membrane protein (MP) bacteriorhodopsin (bR) or the more recently identified xanthorhodopsin (XR). As determined by their characteristic UV-vis absorption spectra and by circular dichroism, the MPs are not significantly perturbed by the oligo-amines carrying from +3 to +6 positive charges. Light microscopy and scanning electron microscope (SEM) imaging provide direct evidence for membrane conjugation. Process efficiency was found to be correlated with the net charge of the oligo-amine used. Membrane conjugation is accomplished within a wide range of pH values (7-2.5); is reversed by NaCl; and does not require the presence of a precipitant (e.g. PEG) nor Ca2+ ions. Some evidence for bilayer fusion is also observed, but only in the presence of the +6 oligo-amine analog.

Promoting crystallization of intrinsic membrane proteins with conjugated micelles.

A new technique for promoting nucleation and growth of membrane protein (MP) crystals from micellar environments is reported. It relies on the conjugation of micelles that sequester MPs in protein detergent complexes (PDCs). Conjugation via amphiphilic [metal:chelator] complexes presumably takes place at the micelle/water interface, thereby bringing the PDCs into proximity, promoting crystal nucleation and growth. We have successfully applied this approach to two light-driven proton pumps: bacteriorhodopsin (bR) and the recently discovered King Sejong 1-2 (KS1-2), using the amphiphilic 4,4'-dinonyl-2,2'-dipyridyl (Dinonyl) (0.7 mM) chelator in combination with Zn2+, Fe2+, or Ni2+ (0.1 mM). Crystal growth in the presence of the [metal-chelator] complexes leads to purple, hexagonal crystals (50-75 µm in size) of bR or pink, rectangular/square crystals (5-15 µm) of KS1-2. The effects of divalent cation identity and concentration, chelator structure and concentration, ionic strength and pH on crystal size, morphology and process kinetics, are described.

Ground state charge transfer complex formation of some metalloporphyrins with aromatic solvents: Further theoretical and experimental investigations.

In our earlier work (Chem. Phys. Letts. 592 (2014) 149-154), a new broad band was observed in the near infrared region (700-900nm) of the steady state absorption spectra of some metalloporphyrins (zinc tetraphenylporphyrin, zinc octaethylporphyrin and magnesium octaethylporphyrin) in aromatic solvents (chlorobenzene, 1,2-dichlorobenzene, benzonitrile, benzene and toluene) at high concentrations (~10-4molL-1). The band was ascribed to be due to ground state charge transfer complexation between solute and solvent molecules. In the present work, density functional theory calculations are carried out to study the possibility of such ground state charge transfer complex formation between zinc tetraphenylporphyrin and four aromatic solvents viz., benzene, toluene, chlorobenzene and benzonitrile with 1:1 and 2:1 solvent-solute stoichiometries. Also, we determined the association constants for the ground state charge transfer complex formation of zinc tetraphenylporphyrin and zinc octaethylporphyrin with two aromatic solvents (benzene and benzonitrile) by Benesi-Hildebrand method.

Direct evidence for heme-assisted solid-state electronic conduction in multi-heme c-type cytochromes.

Multi-heme cytochrome c (Cytc) proteins are key for transferring electrons out of cells, to enable intracellular oxidation to proceed in the absence of O2. In these proteins most of the hemes are arranged in a linear array suggesting a facile path for electronic conduction. To test this, we studied solvent-free electron transport across two multi-heme Cytc-type proteins: MtrF (deca-heme Cytc) and STC (tetra-heme Cytc). Transport is measured across monolayers of these proteins in a solid state configuration between Au electrodes. Both proteins showed 1000× higher conductance than single heme, or heme-free proteins, but similar conductance to monolayers of conjugated organics. Conductance is found to be temperature-independent (320-80 K), suggesting tunneling as the transport mechanism. This mechanism is consistent with I-V curves modelling, results of which could be interpreted by having protein-electrode coupling as rate limiting, rather than transport within the proteins.

Anthropometric and body frame size characteristics in relation to body mass index and percentage body fat among adult Bengalee male brick-kiln workers from Murshidabad, West Bengal, India.

SUMMARY: Anthropometric and body frame size parameters (ABFSP) are used to interpret body mass and to evaluate nutritional status. Objective of the present study was to investigate the interrelationships between ABFSP, percentage body fat (BF%) and body mass index (BMI). The study was carried out in a sample of 141 adult Bengalee healthy male brick-kiln workers (age range 18-59 years) from Murshidabad district in West Bengal, India. Body weight was recorded; anthropometric measurements included height, breadth (elbow, wrist, hand, foot, ankle, knee), circumferences (mid-upper arm, chest, waist, hip, thigh, medial calf) and skinfolds (biceps, triceps, subscapular, suprailiac). Derived ABFSP included sum of breadth and circumferences, frame index, BMI, BF%, sum of skinfolds, ratio of central and peripheral skinfolds, arm muscle area, arm muscle circumference, arm fat area and brachial adipo-muscular ratio. Correlations (age-controlled) between ABFSP, BMI and BF% were highly significant (p < 0.001). The ABFSP and BF% varied significantly (p < 0.0001) in relation to BMI-based nutritional status (BNS). Multinomial logistic regression analysis (age-adjusted) showed ABFSP had statistically significant (p < 0.01) relationships with BNS. There were strong interrelationships between ABFSP, BMI and BF% independent of age. The ABFSP in individuals with normal BMI, suffering from undernutrition (low BMI) or overweight are different.

Solvatochromic Stokes shift and determination of excited state dipole moments of free base and zinc octaethylporphyrin.

Solvent effects on the photophysical properties of free base octaethylporphyrin and zinc octaethylporphyrin are investigated at the ambient temperature (300 K). Steady state electronic absorption and emission spectra of the porphyrins are recorded in different organic solvents of varying polarity. By using solvatochromic Stokes shift method, the dipole moments associated with the first excited singlet states of the presently used porphyrin molecules are determined for the first time, to the best of our knowledge, from Lippert-Mataga, Bakhshiev and Reichardt equations. The dipole moments associated with the singlet ground state of the porphyrin molecules are calculated theoretically by using density functional theory (DFT) method by adopting B3LYP/6-31G(d,p) level using Gaussian 03 package. Moreover, some other photophysical properties (fluorescence quantum yield, fluorescence lifetime, decay rates, etc.) of the porphyrins are measured in different solvents of varying polarity.

Photophysics of Soret-excited free base tetraphenylporphyrin and its zinc analog in solution.

Photophysical properties of free base tetraphenylporphyrin and its zinc analog are investigated in detail in solvents of varying polarity by using steady state and time-resolved techniques. Both the porphyrins are excited at the Soret band to have better signal-to-noise ratio. Also, the fluorescence emission measurements are carried out by using dilute solutions (~10(-7)mol/L) of the fluorophores in order to minimize the self-quenching effect. It is observed that the steady state absorption and emission characteristics of the porphyrin molecules are mainly affected by polarizability (via refractive index) rather than polarity (via dielectric constant) of the moderate to highly polar solvents. As the molecules are highly symmetric in the ground state, the associated dipole moments are found to be very low from quantum chemical calculations performed by density functional theory method by using Gaussian 03 package. The dipole moments associated with the first excited singlet state of the porphyrins are computed by applying solvatochromic Stokes' shift method. To the best of our knowledge, this is the first attempt to calculate the excited state dipole moments of the porphyrins used in the present investigations. Also, fluorescence quantum yield, fluorescence lifetime of the first excited singlet state, radiative and non-radiative rate constants of the porphyrins are reported in solvents of varying polarity.

Prevalence of depressive disorders in the elderly.

Community-based mental health studies have revealed that the point prevalence of depressive disorders in the elderly population of the world varies between 10% and 20%, depending on cultural situations. A retrospective study based on analysis of various study reports was conducted, to determine the median prevalence rates of depressive disorders in the elderly population of India and various other countries in the world. All the studies that constituted the sample were conducted between 1955 and 2005. Included are only community-based, cross-sectional surveys and some prospective studies that had not excluded depression at baseline. These studies were conducted on a homogenous community of the elderly population in the world, who were selected by a simple random sampling technique. After applying the inclusion and exclusion criteria on published and indexed articles, 74 original research studies that surveyed a total of 487,275 elderly individuals, in the age group of 60 years and above, residing in various parts of the world, were included for the final analysis. The median prevalence rate and its corresponding interquartile range were calculated. The chi-square test and chi-square for linear trend were applied. A P value of <.05 was considered as statistically significant. The median prevalence rate of depressive disorders in the world for the elderly population was determined to be 10.3% (interquartile range [IQR], 4.7%-16.0%). The median prevalence rate of depression among the elderly Indian population was determined to be 21.9% (IQR, 11.6%-31.1%). Although there was a significant decrease in the trend of world prevalence of geriatric depression, it was significantly higher among Indians, in recent years, than the rest of the world.