Stepwise evaluation for the risk of metabolic unhealthiness and significant non-alcoholic fatty liver disease in India

Background

Non-communicable diseases including metabolic health disorders are becoming area of concern for low/middle income countries with poor health-care resources. Present study was planned to assess the prevalence of metabolically unhealthy (MU) subjects in the community and proportion of the MU subjects having the risk of significant Non-alcoholic Fatty Liver Disease (NAFLD) using a step-wise evaluation strategy in a resource-poor setting.

Methods

Study was performed in 19 community development blocks of Birbhum district, West Bengal, India. Every fifth member in the electoral list was included for the first step evaluation (n = 79,957/1,019,365, 7.8%) to detect any metabolic risk. Subjects with any metabolic risk in the first step (n = 9819/41,095, 24%) were taken for second step evaluation with Fasting blood glucose (FBG) and ALT. Subjects with elevated FBG and/or ALT in the second step (n = 1403/5283, 27%) were taken into third step evaluation.

Finding

At least one risk factor was found in 51.4% (n = 41,095/79,957). 63% (n = 885/1403) of the subjects with metabolic abnormality (third step) had MU state making its overall prevalence of 1.1% (n = 885/79,957). 53% of MU subjects (n = 470/885) had 'persistently elevated ALT' suggesting the risk of having significant NAFLD.

Interpretation

Step-wise evaluation strategy could detect the subjects at risk, actually having MU state and proportion of MU subjects at risk of having 'persistently elevated ALT' (surrogate of significant NAFLD) in the community with minimum utilization of scarce resources.

Funding

This study was funded by Bristol Myers Squibb Foundation, USA, under the program 'Together on Diabetes Asia' (Project Number: 1205 - LFWB).

Socio-economic inequalities in undiagnosed, untreated, and uncontrolled diabetes mellitus in Bangladesh: is there a gender difference?

OBJECTIVES

We aimed to determine: (1) the prevalence and socio-economic distribution of undiagnosed, untreated, and uncontrolled diabetes mellitus (DM); (2) the relationship between socio-economic status (SES) and undiagnosed, untreated, and uncontrolled DM; and (3) if this relationship is mediated by gender.

STUDY DESIGN

Cross-sectional nationally representative household-based survey.

METHODS

We used data from the Bangladesh Demographic Health Survey from 2017 to 18. Our findings were based on the responses of 12,144 individuals aged 18 years and older. As a measure of SES, we focused on standard of living (hereinafter referred to as wealth). The study's outcome variables were prevalence of total (diagnosed + undiagnosed), undiagnosed, untreated, and uncontrolled DM. We used three regression-based approaches-adjusted odds ratio, relative inequality index, and slope inequality index-to assess different aspects of SES differences in the prevalence of total, undiagnosed, untreated, and uncontrolled DM. We used logistic regression analysis to look at the adjusted association between SES and the outcomes after gender stratification to see whether gender status moderates the association between SES and the targeted outcomes.

RESULTS

In our sample analysis, the age-adjusted prevalence of total, undiagnosed, untreated, and uncontrolled DM was 9.1%, 61.4%, 64.7%, and 72.1%, respectively. Females had a higher prevalence of DM and undiagnosed, untreated, and uncontrolled DM than males. When compared to people in the poor SES group, people in the rich and middle SES groups had 2.60 times (95% confidence interval [CI] 2.05-3.29) and 1.47 times (95% CI 1.18-1.83) higher chance of developing DM. When compared to individuals in the poor SES group, those in the rich SES groups were 0.50 (95% CI 0.33-0.77) and 0.55 times (95% CI 0.36-0.85) less likely to have undiagnosed and untreated DM.

CONCLUSIONS

In Bangladesh, rich SES groups were more likely than poor SES groups to have DM, whereas poor SES groups with DM were less likely than rich SES groups to be aware of their disease and obtain treatment. The government and other concerned parties are urged by this study to pay more attention to developing suitable policy measures to reduce the risk of DM, particularly among rich SES groups, as well as targeted efforts to screen for and diagnose DM in socio-economically disadvantaged groups.

Clinical variables and pre-operative depression levels for prediction of pain severity in patients undergoing heart surgery

Objective: In patients undergoing heart surgery, severe pain is common and may raise the risk of heart conditions, morbidity, and death. The study's goals were to evaluate post-cardiac surgery pain predictors, such as clinical variables and depression, as well as perioperative Pain Severity (PS). Methods: The research included 98 heart surgery patients in total. PS was analysed utilizing a Numerical Rating System (NRS). From the second day after surgery through the seventh day, pain levels were monitored daily. Clinical data was obtained, and depression levels were determined utilizing the Center for Epidemiological Study of Depression (CES-D). Results: From pre-operative levels, pain severe dramatically increased while hospitalized, peaking at day 2 after surgery. Higher CES-D preoperative values in gender, heart function, smoking, and a high Body mass index (BMI). Preoperative CES-D ratings were considerably higher for patients in severe pain than for those with no pain or mild pain. Patients experiencing severe pain (NRS 7 to 10) exhibited considerably greater white blood cell (WBC) counts than those free of pain or mild pain (NRS 0 to 6) (p=0.01). However, there was no association between maximum WBC levels after surgery and CES-D scores. Conclusion: Following surgery, PS considerably increased and was linked to depressive symptoms, gender, heart function, BMI, and smoking. These variables could be used as a starting point for detection and treatment to help stop the progression of acute pain into chronic pain.

Diagnostic criteria, pathogenesis, and precautionary measures for severe renal damage linked with heart surgery: a retrospective analysis

Background: Heart surgery (HS) complications such as renal damage (RD), which is a frequent and major consequence, are linked to higher mortality and morbidity rates as well as a significant financial burden. Several different pathophysiological ideas might explain the multifaceted complexity of the HS-RD pathogenesis. Aim: The purpose of this research is to identify RD after HS and to evaluate the results of diagnostic criteria, pathogenesis, and preventative measures. Methods: This retrospective analysis of HS patients examined the occurrence and impact of several definitions of RD, Renal Damage Network (RDN), and Kidney Disease: Improving Global Outcomes (KDIGO) or risk, injury, failure, loss, and end-stage kidney disease (RIFLE). We also defined transient RD and sustained RD. Results: RIFLE-Risk had the greatest positive probability ratio of every definition, continued with sustained RD (positive likelihood ratio = 2.27) for the best definition. 39 patients with KDIGO RD and all 80 patients having late RD were excluded from the RD defined by RDN criteria. Conclusion: The pathogenesis, definition, diagnosis, and preventative measures of RD in HS patients are discussed in this article. Based on the capacity to forecast short-term mortality, the risk was shown to be the most accurate definition of RD, followed by injury, failure, loss, and end-stage RD.

Role of C and B4C barrier layers in controlling diffusion propagation across the interface of Cr/Sc multilayers

The optical performance of low-bilayer-thickness metallic multilayers (ML) can be improved significantly by limiting the intermixing of consecutive layers at the interfaces. Barrier layers are supposed to exhibit a decisive role in controlling diffusion across the interfaces. The element-specific grazing incidence extended X-ray absorption fine structure technique using synchrotron radiation has been used in conjunction with grazing incidence X-ray reflectivity and diffuse X-ray scattering measurements to study the impact of the two most common barrier layers, viz., C and B₄C, at the interfaces of Cr/Sc MLs. The diffusion propagation is reduced by both the barrier layers; however, it is found that the improvement is more significant with the B₄C barrier layer. It is seen that C forms an intermixed layer with Sc and leads to carbide formation at the interface, which then acts as shielding and prevents further interdiffusion, while B₄C hardly penetrates into Sc and stops the overlap between Sc and Cr directly by wetting the corresponding interface. Thus, the above measurements reveal crucial and precise information regarding the elemental diffusion kinetics at the interfaces of Cr/Sc MLs in a non-destructive way, which is very important for technological applications of these MLs as X-ray optical devices.

Predictors of COVID-19 Vaccine Confidence: Findings from Slums of Four Major Metro Cities of India

There are limited studies on COVID vaccine confidence at the household level in urban slums, which are at high risk of COVID-19 transmission due to overcrowding and poor living conditions. The objective was to understand the reasons influencing COVID-19 vaccine confidence, in terms of barriers and enablers faced by communities in urban slums and informal settlements in four major metro cities in India. A mixed method approach was adopted, where in field studies were conducted during April-May 2021. First, a survey of at least 50 subjects was conducted among residents of informal urban settlements who had not taken any dose of the COVID-19 vaccine in Mumbai, Bengaluru, Kolkata and Delhi; second, a short interview with five subjects who had taken at least one dose of the vaccine in each of the four cities to understand the factors that contributed to positive behaviour and, finally, an in-depth interview of at least 3 key informants in each city to ascertain the vaccination pattern in the communities. The reasons were grouped under contextual, individual/group and vaccine/vaccination specific issues. The most frequent reason (27.7%) was the uncertainty of getting the vaccine. The findings show the need for increasing effectiveness of awareness campaigns, accessibility and the convenience of vaccination, especially among vulnerable groups, to increase the uptake.

Interface modification of Cr/Ti multilayers with C barrier layer for enhanced reflectivity in the water window regime

The influence of a carbon barrier layer to improve the reflectivity of Cr/Ti multilayers, intended to be used in the water window wavelength regime, is investigated. Specular grazing-incidence X-ray reflectivity results of Cr/Ti multilayers with 10 bilayers show that interface widths are reduced to ∼0.24 nm upon introduction of a ∼0.3 nm C barrier layer at each Cr-on-Ti interface. As the number of bilayers increases to 75, a multilayer with C barrier layers maintains almost the same interface widths with no cumulative increase in interface imperfections. Using such interface-engineered Cr/C/Ti multilayers, a remarkably high soft X-ray reflectivity of ∼31.6% is achieved at a wavelength of 2.77 nm and at a grazing angle of incidence of 16.2°, which is the highest reflectivity reported so far in the literature in this wavelength regime. Further investigation of the multilayers by diffused grazing-incidence X-ray reflectivity and grazing-incidence extended X-ray absorption fine-structure measurements using synchrotron radiation suggests that the improvement in interface microstructure can be attributed to significant suppression of inter-diffusion at Cr/Ti interfaces by the introduction of C barrier layers and also due to the smoothing effect of the C layer promoting two-dimensional growth of the multilayer.

Bronchiolitis obliterans syndrome is associated with increased p-glycoprotein expression and loss of glucocorticoid receptor from steroid-resistant proinflammatory CD8+ T cells

Immunosuppressive therapy fails to suppress the production of proinflammatory cytokines, particularly by CD8+ T cells, in stable lung transplant recipients and those undergoing chronic rejection, suggesting that some patients may become relatively resistant to immunosuppressants such as glucocorticoids (GC). We have shown loss of GC receptor (GCR) from the CD8+ cells, and we hypothesized that the drug membrane efflux pump, p-glycoprotein-1 (Pgp), may also be involved in lymphocyte steroid resistance following lung transplant. Pgp/GCR expression and interferon (IFN)-γ/tumour necrosis factor (TNF)-α proinflammatory cytokine production was measured in blood lymphocytes from 15 stable lung transplant patients, 10 patients with bronchiolitis obliterans syndrome (BOS) and 10 healthy aged-matched controls (± prednisolone ± Pgp inhibitor, cyclosporin A ± GCR activator, Compound A) using flow cytometry. Both Pgp+ and Pgp- lymphocyte subsets from all subjects produced IFN-γ/TNF-α proinflammatory cytokines. Pgp expression was increased in CD8+ Pgp+ T cells and correlated with IFN-γ/TNF-α expression and BOS grade. Reduced GCR was observed in CD8+ Pgp- T, natural killer (NK) T-like and NK cells from stable patients compared with controls, and reduced further in CD8+ Pgp- T cells in BOS. The addition of 2·5 ng/ml cyclosporin A and 1 µM prednisolone inhibit IFN-γ/TNF-α production significantly by CD8+ Pgp+ T cells from BOS patients. The addition of 10 µM Compound A and 1 µM prednisolone inhibit IFN-γ/TNF-α production significantly by CD8+ Pgp- T cells from BOS patients. BOS is associated with increased Pgp expression and loss of GCR from steroid-resistant proinflammatory CD8+ T cells. Treatments that inhibit Pgp and up-regulate GCR in CD8+ T cells may improve graft survival.

Exploring the potential of T7 bacteriophage protein Gp2 as a novel inhibitor of mycobacterial RNA polymerase

Over the past six decades, there has been a decline in novel therapies to treat tuberculosis, while the causative agent of this disease has become increasingly resistant to current treatment regimens. Bacteriophages (phages) are able to kill bacterial cells and understanding this process could lead to novel insights for the treatment of mycobacterial infections. Phages inhibit bacterial gene transcription through phage-encoded proteins which bind to RNA polymerase (RNAP), thereby preventing bacterial transcription. Gp2, a T7 phage protein which binds to the beta prime (β') subunit of RNAP in Escherichia coli, has been well characterized in this regard. Here, we aimed to determine whether Gp2 is able to inhibit RNAP in Mycobacterium tuberculosis as this may provide new possibilities for inhibiting the growth of this deadly pathogen. Results from an electrophoretic mobility shift assay and in vitro transcription assay revealed that Gp2 binds to mycobacterial RNAP and inhibits transcription; however to a much lesser degree than in E. coli. To further understand the molecular basis of these results, a series of in silico techniques were used to assess the interaction between mycobacterial RNAP and Gp2, providing valuable insight into the characteristics of this protein-protein interaction.

Continuously Varying Critical Exponents Beyond Weak Universality

Renormalization group theory does not restrict the form of continuous variation of critical exponents which occurs in presence of a marginal operator. However, the continuous variation of critical exponents, observed in different contexts, usually follows a weak universality scenario where some of the exponents (e.g., β, γ, ν) vary keeping others (e.g., δ, η) fixed. Here we report ferromagnetic phase transition in (Sm_1−yNd_y)_0.52Sr_0.48MnO₃ (0.5 ≤ y ≤ 1) single crystals where all three exponents β, γ, δ vary with Nd concentration y. Such a variation clearly violates both universality and weak universality hypothesis. We propose a new scaling theory that explains the present experimental results, reduces to the weak universality as a special case, and provides a generic route leading to continuous variation of critical exponents and multi-criticality.

Association of ABO blood group polymorphism and tuberculosis: A study on Bengalee Hindu caste population, West Bengal, India

Tuberculosis (TB) is an infectious disease commonly caused by the bacillus mycobacterium and worldwide estimation demonstrated that more than 8.6 million people are infected by TB. Many of the previous studies reported the association between TB and ABO blood group polymorphism. In this context, the objective of the present study is to understand the association of ABO blood group polymorphism and TB in Bengalee Hindu caste population. The present study consists of 100 clinically diagnosed TB patients and 100 apparently healthy individuals with no previous history of TB from the same population of the same area. The distribution of ABO phenotypes demonstrated significant (p<0.05) excess of AB blood group in TB patients and significant (p<0.05) decrease of O blood group in controls. Logistic regression analysis revealed that individuals with non O blood group have 1.97 times (95% CI 1.04-3.75) greater chance of developing TB than individuals with O blood group.

Covert Changes in CaMKII Holoenzyme Structure Identified for Activation and Subsequent Interactions

Between 8 to 14 calcium-calmodulin (Ca(2+)/CaM) dependent protein kinase-II (CaMKII) subunits form a complex that modulates synaptic activity. In living cells, the autoinhibited holoenzyme is organized as catalytic-domain pairs distributed around a central oligomerization-domain core. The functional significance of catalytic-domain pairing is not known. In a provocative model, catalytic-domain pairing was hypothesized to prevent ATP access to catalytic sites. If correct, kinase-activity would require catalytic-domain pair separation. Simultaneous homo-FRET and fluorescence correlation spectroscopy was used to detect structural changes correlated with kinase activation under physiological conditions. Saturating Ca(2+)/CaM triggered Threonine-286 autophosphorylation and a large increase in CaMKII holoenzyme hydrodynamic volume without any appreciable change in catalytic-domain pair proximity or subunit stoichiometry. An alternative hypothesis is that two appropriately positioned Threonine-286 interaction-sites (T-sites), each located on the catalytic-domain of a pair, are required for holoenzyme interactions with target proteins. Addition of a T-site ligand, in the presence of Ca(2+)/CaM, elicited a large decrease in catalytic-domain homo-FRET, which was blocked by mutating the T-site (I205K). Apparently catalytic-domain pairing is altered to allow T-site interactions.

A single amino acid change in inhibitory killer cell Ig-like receptor results in constitutive receptor self-association and phosphorylation

Signaling by immunoreceptors is often initiated by phosphorylation of cytosolic tyrosines, which then recruit effector molecules. In the case of MHC class I-specific inhibitory receptors, phosphorylation of cytosolic tyrosine residues within ITIMs results in recruitment of a protein tyrosine phosphatase that blocks activation signals. Recent work showed that signaling by an HLA-C-specific killer cell Ig-like receptor (KIR) is independent of signaling by activation receptors. It is not known how ITIM phosphorylation is initiated and regulated. In this article, we show that substitution of His-36 in the first Ig domain of KIR2DL1 with alanine (KIR2DL1-H36A) resulted in constitutive KIR2DL1 self-association and phosphorylation, as well as recruitment of tyrosine phosphatase SHP-1. Furthermore, substitution of His-36 with a similar bulky amino acid, phenylalanine, maintained the receptor in its unphosphorylated state, suggesting that steric hindrance by the His-36 side chain prevents constitutive KIR2DL1 self-association and ITIM phosphorylation. The equally strong phosphorylation of KIR2DL1 and KIR2DL1-H36A after inhibition of tyrosine phosphatase by pervanadate suggested that KIR2DL1-H36A is selectively protected from dephosphorylation. We propose that KIR phosphorylation is controlled by the accessibility of ITIM to tyrosine phosphatases and that KIR binding to HLA-C must override the hindrance that His-36 puts on KIR2DL1 self-association. Expression of KIR2DL1-H36A on NK cells led to stronger inhibition of lysis of HLA-C(+) target cells than did expression of wild-type KIR2DL1. These results revealed that ITIM phosphorylation is controlled by self-association of KIR and that His-36 serves as a gatekeeper to prevent unregulated signaling through KIR2DL1.

Primary cutaneous histoplasmosis simulating Molluscum contagiosum

Primary cutaneous histoplasmosis in a HIV positive patient ie isolated cutaneous involvement without any deeper structures is a very rare entity. Only a handful cases have been reported worldwide. This patient presented with cutaneous lesion simulating Molluscum but histopathology revealed Histoplasma capsulatum. The patient had no deep organ involvement. The patient was put on Itraconazole which caused rapid dissolution of the lesions. He was subsequently put on HAART and discharged.

A comparative pharmacokinetic study of a fixed dose combination for essential hypertensive patients: a randomized crossover study in healthy human volunteers

BACKGROUND

This study was aimed to investigate the relative bioavailability of fixed-dose-combination (FDC) product of amlodipine, telmisartan and hydrochlorothiazide with individual marketed products in healthy male volunteers. Control of blood pressure with fixed dose combination of the above drugs acting through different mechanism have a benefit of convenient dosing in terms of compliance, lower the dose and subsequently reduce the side effects.

METHODS

The authors investigated the relative bioavailability under a fasting state of the 3 drugs in a randomized, open-label, 2-treatment, 2-period, 2-sequence, crossover bioequivalence study with a washout period of 21 days. Plasma concentration of the analytes were assayed in timed samples with a simple, highly sensitive and rapid validated method using HPLC coupled to tandem mass spectrometry that had a lower limit of quantification of 1 ng/mL for all the 3 components.

RESULTS

Test and reference formulations gave a mean Cmax of 5.234±0.914 ng/mL and 4.991±0.563 ng/mL, 108.839±13.601 ng/mL and 114.783±12.315 ng/mL and 97.814±10.779 ng/mL and 93.731±10.018 ng/mL for amlodipine, telmisartan and hydrochlorothiazide respectively. The AUC0-t of amlodipine, telmisartan and hydrochlorothiazide was 161.484 ng.h/mL, 1 917.644 ng.h/mL and 822.847 ng.h/mL for test formulation and 162.108 ng.h/mL, 2 014.764 ng.h/mL and 829.323 ng.h/mL for reference in the fasting state.

CONCLUSION

The 90% confidence intervals for the test/reference ratio of the pharmacokinetic parameters in fasting state (mean Cmax, AUC0-t, and AUC0-∞) were within the acceptable range of 80.00-125.00. Thus, these findings clearly indicate that the FDC product is bioequivalent with the individual marketed products in terms of rate and extent of drug absorption and is well tolerated with no significant adverse reactions.

Metal-enhanced immunoassays

The surface-confined assay format is one of the most convenient detection formats used in many immunoassays. Fluorescence emission from monolayers of dyes requires a strong excitation and good detection system. Such samples are susceptible to artifacts due to background fluorescence from substrates. We demonstrate that using silver nanostructures deposited on the slide substrate can significantly enhance measured fluorescence, reduce unwanted background and increase photostability of the used probes. Using thin layers of polymer doped with fluorescein, we tested two nanostructures--silver island films (SIFs) deposited on glass slides and self-assembled colloidal structures (SACS) deposited on thin silver film. The SACS surfaces show extraordinary fluorescence enhancements: over 100-folds in hot spots. We applied these surfaces for enhanced Alexa488 model immunoassay.

The protective effect of astrocyte-derived 14,15-epoxyeicosatrienoic acid on hydrogen peroxide-induced cell injury in astrocyte-dopaminergic neuronal cell line co-culture

Astrocytes perform several functions that are essential for normal neuronal activity. They play a critical role in neuronal survival during ischemia and other degenerative injuries and also modulate neuronal recovery by influencing neurite outgrowth. In this study, we investigated the neuroprotective effects of astrocyte-derived 14,15-epoxyeicosatrienoic acid (14,15-EET), metabolite of arachidonic acid by cytochrome P450 epoxygenases (CYP), against oxidative stress induced by hydrogen peroxide (H(2)O(2)). We found that dopaminergic neuronal cells (N27 cell line) stimulated with two different doses of H(2)O(2) (0.1 and 1mM) for 1h showed decreased cell viability compared to the control group, while astrocytes showed less cell death after stimulation with the same doses of H(2)O(2) for 1h. Dopaminergic neuronal cells (N27 cell line) pretreated with different doses of 14,15-EET (0.1-30 μM, 30 min) before H(2)O(2) stimulation also showed increased cell viability. Furthermore, pre-treatment of the co-cultured cells with 12-(3-adamantan-1-yl-ureido)-dodecanoic acid, an inhibitor of the EET metabolizing enzyme, soluble epoxide hydrolase (sEH), before H(2)O(2) stimulation (1mM, for 1h) increased cell viability. It also increased the endogenous level of 14,15-EET in the media compared to control group. However, pretreatment with the CYP epoxygenase inhibitor miconazole (1-20 μM, 1h) before H(2)O(2) (1mM, 1h) stimulation showed decreased cell viability. Our data suggest that 14,15-EET which is released from astrocytes, enhances cell viability against oxidant-induced injury. Further understanding of the mechanism of 14,15-EET-mediated protection in dopaminergic neurons is imperative, as it could lead to novel therapeutic approaches for treating CNS neuropathologies, such as Parkinson's disease.

Fluorescence polarization and fluctuation analysis monitors subunit proximity, stoichiometry, and protein complex hydrodynamics

Förster resonance energy transfer (FRET) microscopy is frequently used to study protein interactions and conformational changes in living cells. The utility of FRET is limited by false positive and negative signals. To overcome these limitations we have developed Fluorescence Polarization and Fluctuation Analysis (FPFA), a hybrid single-molecule based method combining time-resolved fluorescence anisotropy (homo-FRET) and fluorescence correlation spectroscopy. Using FPFA, homo-FRET (a 1–10 nm proximity gauge), brightness (a measure of the number of fluorescent subunits in a complex), and correlation time (an attribute sensitive to the mass and shape of a protein complex) can be simultaneously measured. These measurements together rigorously constrain the interpretation of FRET signals. Venus based control-constructs were used to validate FPFA. The utility of FPFA was demonstrated by measuring in living cells the number of subunits in the α-isoform of Venus-tagged calcium-calmodulin dependent protein kinase-II (CaMKIIα) holoenzyme. Brightness analysis revealed that the holoenzyme has, on average, 11.9±1.2 subunit, but values ranged from 10–14 in individual cells. Homo-FRET analysis simultaneously detected that catalytic domains were arranged as dimers in the dodecameric holoenzyme, and this paired organization was confirmed by quantitative hetero-FRET analysis. In freshly prepared cell homogenates FPFA detected only 10.2±1.3 subunits in the holoenzyme with values ranging from 9–12. Despite the reduction in subunit number, catalytic domains were still arranged as pairs in homogenates. Thus, FPFA suggests that while the absolute number of subunits in an auto-inhibited holoenzyme might vary from cell to cell, the organization of catalytic domains into pairs is preserved.

Differential effect of amyloid β on the cytochrome P450 epoxygenase activity in rat brain

One of the prominent features of Alzheimer's disease is the excessive accumulation of the protein amyloid beta (Aβ) in certain areas of the brain leading to neurodegeneration. Aβ is cytotoxic and disrupts several cytoprotective pathways. Recent literature has demonstrated that certain cytochrome P450 (CYP) products are neuroprotective, including epoxide metabolites of arachidonic acid (AA), epoxyeicosatrienoic acids (EETs). The action of Aβ with respect to regionally produced EETs in the brain has yet to be defined. Epoxygenases metabolize AA into four regioisomers of EETs (14,15-, 11,12-, 8,9- and 5,6-EET). EETs are rapidly degraded into dihydroxyeicosatrienoic acids (DiHETEs) by soluble epoxide hydrolase (sEH). To determine the effect of Aβ on the epoxygenase activity in different regions of the brain, microsomes were prepared from the cerebrum and cerebellum of adult Sprague-Dawley rats and incubated with 1 and 10 μM Aβ for 30 min after which epoxygenase activity assay was performed. Mass spectrometry indicated that incubation with Aβ reduced 14,15-EET production by 30% as compared to vehicle in the cerebrum, but not in the cerebellum. When we separated the cerebrum into cortex and hippocampus, significant decrease in the production of total EETs and DiHETEs were seen in presence of Aβ (81% and 74%) in the cortex. Moreover, 11,12-EET production was decreased to ∼70% of vehicle in both cortex and hippocampus. Epoxygenase activity in the cultured astrocytes and neurons also showed reduction in total EET and DiHETE production (to 80% and ∼70% of vehicle respectively) in presence of Aβ. Altogether, our data suggest that Aβ reduces epoxygenase activity differentially in a region-specific and cell-specific manner. The reduction of cytoprotective EETs by Aβ in the cerebrum may make it more prone to degeneration than the cerebellum. Further understanding of these interactions will improve our ability to protect against the pathology of Alzheimer's disease.

Fluorescent properties of antioxidant cysteine ABZ analogue

The antioxidant properties of aminobenzamide cysteine (ABZ Cys) makes it a molecule that can potentially be used as a drug in oxidative stress related diseases and delivered in the form of a nanoparticles. Here we have studied the photo-physical properties of ABZ Cys, a fluorescent analogue of a popular antioxidant N-acetyl cysteine (NAC). We have compared ABZ Cys steady state and time-resolved fluorescence properties with its parent compounds anthranilic acid and anthranilamide in solution as well as in poly-vinyl alcohol (PVA) polymer films. ABZ Cys did not show any significant shift in absorption after entrapment in PVA film, but there was a shift towards shorter wavelengths in the emission peak compared to the phosphate buffer solution. Fluorescence lifetimes and quantum yields indicated a slight quenching of ABZ Cys fluorescence in comparison to the cysteine-less parent compounds. We also demonstrated that very low concentrations of ABZ Cys, such as 100 nM, are readily detected by a commercial spectrofluorometer. Hence we have established the possible use of ABZ Cys in biomedical applications.

Förster resonance energy transfer evidence for lysozyme oligomerization in lipid environment

Intermolecular time-resolved and single-molecule Förster resonance energy transfer (FRET) have been applied to detect quantitatively the aggregation of polycationic protein lysozyme (Lz) in the presence of lipid vesicles composed of phosphatidylcholine (PC) and its mixture with 5, 10, 20, or 40 mol % of phosphatidylglycerol (PG) (PG5, PG10, PG20, or PG40, respectively). Upon binding to PC, PG5, or PG10 model membranes, Lz was found to retain its native monomeric conformation, while increasing content of anionic lipid up to 20 or 40 mol % resulted in the formation of Lz aggregates. The structural parameters of protein self-association (the degree of oligomerization, the distance between the monomers in protein assembly, and the fraction of donors present in oligomers) have been derived. The crucial role of the factors such as lateral density of the adsorbed protein and electrostatic and hydrophobic Lz-lipid interactions in controlling the protein self-association behavior has been proposed.