Synthesis and bio-evaluation of newer dihydropyridines and tetrahydropyridines based glycomimetic azasugars

This study presents the synthesis and bio-evaluation of new triazolylated dihydropyridine and tetrahydropyridine azasugar scaffolds (F1-14). Azasugar glycomimetics are the synthetic substances that mimic the structural and functional characteristics of natural carbohydrates showcasing promising potential as therapeutic agents for diabetes. The α-glucosidase inhibitory activity of synthesized final compounds were evaluated against the commercially available α-glucosidase enzyme. Majority of the screened compounds displayed excellent inhibition with IC50 values ranging from 2.12 to 75.11 μM, when compared to the standard drug Acarbose. Particularly, compound F5 with IC50 value of 2.12 μM was found to be the most active compound among the series. Further molecular docking studies of selected ligands were performed to investigate the binding interactions with enzyme active sites. Their specific binding patterns have been analysed with the binding sites of Saccharomyces cerevisiae α-glucosidase. These findings suggest these candidates as the potential leads for the anti-diabetic activity.

Binding studies of potential amyloid-β inhibiting chalcone derivative with bovine serum albumin

Chalcones (α-phenyl-β-benzoylethylene) and their natural-source derivatives have been investigated for their remarkable biological activities, like neuroprotective, anti-inflammatory, and anti-tumor properties. A triazole chalcone ligand (E)-3-(4-(dimethylamino)phenyl)-1-(4-((1-(2-(4-((E)-3-(4(dimethylamino)phenyl)acryloyl)phenoxy)ethyl)-1H-1,2,3-triazol-4-yl)methoxy)phenyl)prop-2-en-1-one (L1) was synthesized by Cu(I)- catalysed click reaction. The mechanistic properties of L1 for therapy were evaluated by analyzing the binding interactions between L1 and bovine serum albumin (BSA) through photophysical and computational studies. The structural elucidation of ligand L1 was carried out by NMR and mass spectrometry. The Aβ inhibitory activity of L1 was studied by thioflavin T assay and transmission electron microscopy. The biomolecular interaction of L1 with bovine serum albumin was examined through multi-spectroscopic techniques in combination with in silico studies. UV-Visible absorption, fluorescence spectroscopy, circular dichroism, Förster resonance energy transfer, and three-dimensional fluorescence studies confirmed the formation of a BSA-L1 complex. The potential binding sites, mechanism of interactions, and variations in the environment of tyrosine and tryptophan amino acid residues of BSA were assessed at different temperatures. The binding constant for the Static quenching mechanism of intrinsic fluorescence of BSA was of the order of 105 M-1. The esterase enzyme activity assay in the presence of L1 revealed an increase in the protein enzyme activity. Molecular docking studies suggested L1 was predominantly bound to BSA by hydrogen bonds and Van der Waals forces.

Binding interactions of Vildagliptin with pepsin: A multi-spectroscopic and in-silico approach and a comparative account with metformin

Vildagliptin (VDG) and Metformin (Met) belong to a class of dipeptidylpeptidase-4 (DPP-4) inhibitor and biguanide, respectively and used for the management of diabetes mellitus type II (DMTII). Both the drugs are orally available which leads to various side effects due to its oral ingestion. Occurrence of these side effects might be due to some interactions with pepsin at a molecular level. Therefore, in order to investigate these interactions, multi-spectroscopic and in-silico techniques have been extensively studied to identify the binding characteristics of VDG with pepsin. Fluorescence data suggested that the quenching is due to dynamic and static mechanism and static was dominant one. However, fluorescence and UV-Vis spectroscopic measurement analysis suggested that VDG tends to associate with pepsin, via ground-state complex formation. Fluorescence study revealed the binding-constant value which was found to be 0.559 × 103 M-1 at 298.15 K that is non-covalent in nature. VDG-pepsin complex shows exothermic and spontaneous binding as confirmed by the calculated values of ΔH, ΔS, and ΔG, are majorly caused by van der Waals forces and H-bonding interactions. CD spectra of pepsin in presence of VDG confirmed post binding conformational change. Enzyme-activity assay showed that activity of pepsin was decreased by upto 28 %. FRET analysis suggested that energy transfer efficiency is negligible for VDG-pepsin interaction. In-silico analysis reveals that H-bonding and electrostatic negative forces are the significant driving forces involved in the interaction of VDG and pepsin.

Multispectroscopic studies of binding interaction of phosmet with bovine hemoglobin

Phosmet is a phthalimide derived broad spectrum organophosphate pesticide which is vastly used across the globe to protect several ornamental or horticulture crops. The toxicity of phosmet is of utmost concern because of its direct effect on the nervous system of the victim after exposure. The mechanism of phosmet toxicity was explored by the interaction with the model blood protein which is hemoglobin. Bovine Hemoglobin (BHb) is a major protein of red blood cells (RBCs) that plays an important role in the exchange of gases for respiration and ensures adequate oxygen supply to tissues for oxygenation. In the current study, the interaction of BHb with phosmet was revealed using various spectroscopic techniques. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) studies of BHb in the presence of phosmet showed secondary structural changes in the protein post binding, Fluorescence study shows the involvement of the dynamic quenching predominantly, Van't Hoffs thermodynamic study showed negative enthalpy value and free energy change and negative entropy change that revealed the involvement of hydrogen bonding and van der Waal forces predominantly further revealing spontaneous nature of binding interaction. The shift in Ultraviolet-visible spectra also revealed the nature of the interaction. In-silico study finally deduced the involvement of hydrogen bonding and polar interaction. The study inferred the moderate interaction of BHb with phosmet.

Luminescence studies of binding affinity of vildagliptin with bovine serum albumin

Vildagliptin (VDG)is a frontier drug for diabetes mellitus. It is prescribed both in the monotherapy as well as in an amalgamation with other antidiabetic drugs. Drug-serum protein binding is an essential parameter which influences ADME properties of the drug. In current study, binding of VDG with serum protein (bovine serum albumin: BSA) was investigated using multi-spectroscopic techniques. A computational approach was also employed to identify the binding affinity of VDG with BSA at both Sudlow I and II sites. An enzyme activity assay specific for esterase was also investigated to know the post-binding consequences of VDG with BSA. Fluorescence spectra of BSA samples treated with VDG shows static quenching with binding parameters for VDG-BSA complex show single class of equivalent binding stoichiometry(n = 1.331) and binding constant 1.1 x 10⁴M^-1 at 298.15 K. The binding constant indicates important role of non-polar interactions in the binding process. Fluorescence resonance energy transfer (FRET) analysis of VDG absorption spectra and emission spectrum of BSA confirmed no significant resonance in energy transfer. Synchronous fluorescence of BSA after binding with VDG show maximum changes in emission intensity at tryptophan (Trp) residues. Post binding with VDG, BSA conformation changes as suggested by circular dichorism (CD) spectra of BSA and this lead to enhanced protein stability as indicated by a thermal melting curve of BSA.Communicated by Ramaswamy H. Sarma.

DNA binding and antiradical potential of ethyl pyruvate: Key to the DNA radioprotection

DNA is the store house of all necessary hereditary information for growth of cells and tissues. Physiological functionality of DNA depends on its 3D helical structure and any distortion in a structure may lead to mutation and genomic instability that may translate into disease like cancer. In order to prevent DNA damage, an exogenous compound is required that can either scavenge the excess free radicals or enhance the structural integrity of DNA through binding. In the present study, the binding mechanism of ethyl pyruvate (EP) with DNA models using different spectroscopic techniques was investigated for their structural integrity. Besides, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays were performed to determine the antioxidant scavenging of EP. Plasmid DNA relaxation assay was performed to assess the radioprotection efficacy of EP in the plasmid DNA. Circular dichroism (CD) and UV-Vis absorbance spectroscopic data confirmed the conformation change in ctDNA upon binding with EP. The molecular docking visualized that EP stacks between the DNA bases with a glide score of -2.117 kcalmol while EP binds in the minor groove region of DNA with the glide score of -1.414 kcalmol . DPPH and FRAP data confirmed that EP scavenges significantly radicals at higher concentrations. In vitro radioprotection study in plasmid DNA pBR322 showed that EP retained the supercoiled form of plasmid DNA at 50 Gy radiation dose.

Yeast techniques for modeling drugs targeting Bcl-2 and caspase family members

Development of drugs targeting Bcl-2 relatives and caspases, for treating diseases including cancer and inflammatory disorders, often involves measuring interactions with recombinant target molecules, and/or monitoring cancer cell killing in vitro. Here, we present yeast-based methods for evaluating drug-mediated inhibition of Bcl-2 relatives or caspases. Active Bax and caspases kill Saccharomyces cerevisiae, and pro-survival Bcl-2 proteins can inhibit Bax-induced yeast death. By measuring the growth or adenosine triphosphate content of transformants co-expressing Bax with pro-survival Bcl-2 relatives, we found that the Bcl-2 antagonist drugs ABT-737 or ABT-263 abolished Bcl-2 or Bcl-x_L function and reduced Bcl-w activity, but failed to inhibit Mcl-1, A1 or the poxvirus orthologs DPV022 and SPPV14. Using this technique, we also demonstrated that adenoviral E1B19K was resistant to these agents. The caspase inhibitor Q-VD-OPh suppressed yeast death induced by caspases 1 and 3. Yeast engineered to express human apoptotic regulators enable simple, automatable assessment of the activity and specificity of candidate drugs targeting Bcl-2 relatives or caspases.

Endothelial dysfunction in ankylosing spondylitis improves after tumor necrosis factor-alpha blockade

Chronic inflammation in ankylosing spondylitis (AS) is associated with vascular endothelial dysfunction. Infliximab improves inflammatory disease activity in AS patients, but its effect on endothelial dysfunction has still not been tested in these patients. Twelve anti-TNF naive AS patients (mean age, 32.6 +/- 3.94 years; disease duration, 5.6 +/- 0.8 years) with high disease activity [Bath ankylosing spondylitis disease activity index (BASDAI score > 4)] despite treatment with stable doses of conventional disease modifying anti-rheumatic drugs (DMARDs) were investigated. Inflammatory disease activity [BASDAI and Bath ankylosing spondylitis functional index (BASFI) scores, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels], serum nitrite concentration, and endothelium-dependent and endothelium-independent vasodilation of the brachial artery were measured at baseline and 12 weeks of therapy after single intravenous infusion of infliximab (5 mg/kg). Previous DMARD(s) regimen remained unchanged throughout the study period. After treatment with infliximab, flow-mediated vasodilation improved from 9.81 +/- 1.70% to 26.93 +/- 2.34% (p < 0.001), whereas there was no significant change in endothelium-independent vasodilation with nitroglycerin and baseline diameter (13.65 +/- 2.10% versus 14.59 +/- 1.93%, p = 0.08, and 4.45 +/- 0.15 versus 4.46 +/- 0.15 mm, p = 0.3, respectively). Nitrite concentration reduced from 6.50 +/- 0.21 to 2.57 +/- 0.18 micromol/l (p < 0.001), ESR from 40.90 +/- 6.00 to 11.50 +/- 1.38 mm in the first hour (p < 0.001), and CRP level from 29.08 +/- 4.11 to 2.69 +/- 0.43 mg/dl (p < 0.001). BASDAI and BASFI scores were significantly reduced from 5.40 +/- 1.14 to 1.40 +/- 0.70 (p < 0.05) and 5.05 +/- 1.76 to 0.20 +/- 0.63 (p < 0.05), respectively. The study suggests that in ankylosing spondylitis, endothelial dysfunction is a part of the disease process and infliximab improves both endothelial dysfunction and inflammatory disease activity.

Joint thresholding and quantizer selection for compression of medical ultrasound images in the wavelet domain

This paper introduces a simple and efficient technique for compression of medical ultrasound (US) images in the wavelet domain. The statistics of subband wavelet coefficients are modelled using the generalized Gaussian distribution (GGD). By exploiting these statistics, a uniform scalar quantizer is designed which adapts very well to the changing statistics of the signal across various subbands and scales. To increase the quantization performance, a threshold is chosen adaptively to zero-out the insignificant wavelet coefficients in the detail subbands before quantization. A distinctive feature of the proposed technique is that it unifies the two approaches to image adaptive coding: rate-distortion (R-D) optimized quantizer selection and R-D optimal thresholding, in order to increase the compression performance of the coder. The operational R-D criterion used for joint optimization is derived in the minimum description length (MDL) framework. The experimental results show that the joint R-D optimization leads to significant improvement in the compression performance of the proposed coder, named JTQ-WV, over the best state-of-the-art image coder, SPIHT. For example, the coding of US images at 0.25 bpp by JTQ-WV yields a PSNR gain of 1.0 dB over the benchmark SPIHT.

Effect of spironolactone on endothelial dysfunction in rheumatoid arthritis

OBJECTIVE

Chronic inflammation in rheumatoid arthritis (RA) is associated with vascular endothelial dysfunction. The aim of this study was to determine the effect of spironolactone on endothelial function in anti-tumour necrosis factor (TNF)-naive RA patients.

METHODS

Twenty-four anti-TNF-naive RA patients (mean age 49 +/- 1.8 years; disease duration 8.5 +/- 5.8 years) with high disease activity [Disease Activity Score including a 28-joint count (DAS28 > 5.1)] despite treatment with stable doses of conventional disease-modifying anti-rheumatic drugs (DMARDs) were investigated. Inflammatory disease activity [DAS28 and Health Assessment Questionnaire-Disability Index (HAQ-DI) scores, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP)], serum markers of endothelial dysfunction, serum nitrite concentration, and endothelium-dependent and -independent vasodilation of the brachial artery were measured before and after 12 weeks of therapy with oral spironolactone 2 mg/kg/day.

RESULTS

After treatment with spironolactone, flow-mediated vasodilation (FMD) improved from 3.18 +/- 0.46% to 3.95 +/- 0.49% (p < 0.001) whereas there was no significant change in endothelium-independent vasodilation with nitroglycerin and baseline diameter (18.4 +/- 1.15% vs. 18.3 +/- 1.13%, p = 0.046, and 3.5 +/- 0.1 vs. 3.52 +/- 0.1 mm, p = 0.952, respectively); serum nitrite concentration was reduced significantly from 6.9 +/- 0.34 to 6.8 +/- 0.33 micromol/L (p < 0.001), ESR from 59.90 +/- 4.86 to 51.22+/-4.26 mm in the first hour (p < 0.001), and CRP level from 15.2+/-3.8 to 9.4+/-2.6 mg/dL (p = 0.019). DAS28 and HAQ-DI scores were significantly reduced, from 6.9+/-0.25 to 4.1+/-0.31 (p < 0.05) and from 1.47+/-0.09 to 0.69+/-0.1 (p < 0.05), respectively.

CONCLUSIONS

The study suggests that, in RA, endothelial dysfunction is part of the disease process and treatment with spironolactone improves both endothelial dysfunction and inflammatory disease activity in RA.

Wavelet based compression of medical ultrasound images using vector quantization

In this paper, an efficient technique for compression of medical ultrasound (US) images is proposed. The technique is based on wavelet transform of the original image combined with vector quantization (VQ) of high-energy subbands using the LBG algorithm. First, we analyse the statistical behaviour of wavelet coefficients in US images across various subbands and scales. The analysis show that most of the image energy is concentrated in one of the detail subband, either in the vertical detail subband (most of the time) or in the horizontal subband. The other two subbands at each decomposition level contribute negligibly to the total image energy. Then, by exploiting this statistical analysis, a low-complexity image coder is designed, which applies VQ only to the highest energy subband while discarding the other detail subbands at each level of decomposition. The coder is tested on a series of abdominal and uterus greyscale US images. The experimental results indicate that the proposed method clearly outperforms the JPEG2000 (Joint Photographers Expert Group) encoder both qualitatively and quantitatively. For example, without using any entropy coder, the proposed method yields a peak signal to noise ratio gain of 0.2 dB to 1.2 dB over JPEG2000 on medical US images.

Performance improvement of the SPIHT coder based on statistics of medical ultrasound images in the wavelet domain

This paper proposes some modifications to the state-of-the-art Set Partitioning In Hierarchical Trees (SPIHT) image coder based on statistical analysis of the wavelet coefficients across various subbands and scales, in a medical ultrasound (US) image. The original SPIHT algorithm codes all the subbands with same precision irrespective of their significance, whereas the modified algorithm processes significant subbands with more precision and ignores the least significant subbands. The statistical analysis shows that most of the image energy in ultrasound images lies in the coefficients of vertical detail subbands while diagonal subbands contribute negligibly towards total image energy. Based on these statistical observations, this work presents a new modified SPIHT algorithm, which codes the vertical subbands with more precision while neglecting the diagonal subbands. This modification speeds up the coding/decoding process as well as improving the quality of the reconstructed medical image at low bit rates. The experimental results show that the proposed method outperforms the original SPIHT on average by 1.4 dB at the matching bit rates when tested on a series of medical ultrasound images. Further, the proposed algorithm needs 33% less memory as compared to the original SPIHT algorithm.

Space-frequency quantiser design for ultrasound image compression based on minimum description length criterion

The paper addresses the problem of how the spatial quantisation mode and subband adaptive uniform scalar quantiser can be jointly optimised in the minimum description length (MDL) framework for compression of ultrasound images. It has been shown that the statistics of wavelet coefficients in the medical ultrasound (US) image can be better approximated by the generalised Student t-distribution. By combining these statistics with the operational rate-distortion (RD) criterion, a space-frequency quantiser (SFQ) called the MDL-SFQ was designed, which used an efficient zero-tree quantisation technique for zeroing out the tree-structured sets of wavelet coefficients and an adaptive scalar quantiser to quantise the non-zero coefficients. The algorithm used the statistical 'variance of quantisation error' to achieve the different bit-rates ranging from near-lossless to lossy compression. Experimental results showed that the proposed coder outperformed the set partitioning in hierarchical trees (SPIHT) image coder both quantitatively and qualitatively. It yielded an improved compression performance of 1.01 dB over the best zero-tree based coder SPIHIT at 0.25 bits per pixel when averaged over five ultrasound images.

Sonographic diagnosis of diastematomyelia in utero: a case report and literature review

Fetal diastematomyelia is a rare form of spinal dysraphism that is characterized by a complete or incomplete division of the spinal cord by an osseous or fibrocartilaginous septum. A case of diastematomyelia, which was detected on the routine third trimester detailed ultrasound scan, is presented. The diagnosis was based on the detection of an echogenic focus in the posterior aspect of the spine in association with widening of the interpedicular vertebral space. The case illustrates that diastematomyelia can occur in the absence of overt spina bifida and that prenatal detection will allow timely postnatal investigation and treatment. Prenatal literature is further reviewed to assess the clinical significance of this finding.

Stressful family life events and nonspecific somatic complaints in school children

The relationship between stressful family life events and somatic complaints in 477 school children was studied. There was a significant association between life events and somatic complaints, with a general trend for somatic complaints to increase in almost direct proportion to the number of family life events. Overall occurrence of these nonspecific symptoms was more in girls. The somatic complaints were significantly more in children from nuclear families and of illiterate or poorly educated mothers. No significant association was observed between somatic complaints and number of children in the family or socio-economic status. Assessment of psychodevelopmental tasks and family environment during routine check up of children by the school health teams and their appropriate training in this field should be stressed upon.

Enuresis: analysis of 100 cases

One hundred children with enuresis were studied to find out various factors responsible for this condition. Enuresis was more frequent in first born, service class and bottle fed children. There was a significant role of stress factors in causation of enuresis. We found a higher frequency of behavioral symptoms among children with enuresis. There was no significant correlation between enuresis and sex, education of parents, social class, sleep patterns, age of mother at marriage and intellectual grades of the children. Worm infestations, giardiasis, amebiasis and urinary infection were seen in 70% of cases. General body weakness, cold and nervousness were the common causes of enuresis in the parents' opinion. The main reason for not seeking the treatment at an early stage in view of parents' was that they thought enuresis a normal variant.