Displaying publications 1 - 20 of 45 in total

Abstract:
Sort:
  1. Aad G, Abbott B, Abeling K, Abicht NJ, Abidi SH, Aboulhorma A, et al.
    Phys Rev Lett, 2024 Jan 12;132(2):021803.
    PMID: 38277607 DOI: 10.1103/PhysRevLett.132.021803
    The first evidence for the Higgs boson decay to a Z boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around 140  fb^{-1} for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is 2.2±0.7 times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.
  2. Das AK
    Indian J Surg, 2011 Aug;73(4):245-50.
    PMID: 22851835 DOI: 10.1007/s12262-011-0307-5
    An ethically conducted randomised controlled trial (RCT) is the backbone of evidence based medicine. In surgical practice however, RCTs have taken a backseat, drawing much adverse comment. There are several reasons to explain surgeons' disinclination to conduct RCTs. These include many practical difficulties such as the problem of blinding surgical procedures, design and funding issues. There are also many ethical issues which need to be considered including the concept of equipoise as well as the ethical issues associated with sham surgery as a control. While there is no doubt that RCTs are essential and in fact have helped to weed out several unnecessary surgical procedures, it is important not to lose sight of the fact that they may not be always necessary in order to obtain evidence in favour of a procedure. Possible solutions could be to follow guidelines that have been issued by learned bodies and a strict adherence to all ethical norms that have been recommended in the conduct of trials.
  3. Das AK, Gopurappilly R, Parhar I
    Curr Stem Cell Res Ther, 2011 Jun;6(2):93-104.
    PMID: 21190537
    Spinal cord injuries (SCIs) are a common form of trauma that leaves a huge trail of morbidity and human suffering in its wake. They occur mostly among the young, causing severe physical, psychological, social and economic burdens. The treatment of this condition has rather been disappointing; most of the management strategies being mainly supportive and prophylactic. In recent years there has been an emerging interest in the use of stem cells to regenerate the nervous tissue that has been damaged or lost. Although there has been much hype and unfounded hope, modest successes have been witnessed, and it is possible that these therapeutic strategies may have much more to offer in the future. This paper will review the current strategies of exploring cell-based therapies, mainly different types of stem cells to treat SCI along with the evidence that has been accumulated over the past decade in a rational bench-to-bedside approach. Furthermore, critical aspects such as the mode of delivery and ethical considerations are also discussed along with feasible suggestions for future translational research to provide a contextual picture of the current state of advancements in this field. The impediments to regeneration in the site of injury are briefly explained along with the benefits and drawbacks of different cell types used in the treatment of this condition. We hope that this review will offer a significant insight into this challenging clinical condition.
  4. Das AK, Pal R
    J Tissue Eng Regen Med, 2010 Aug;4(6):413-21.
    PMID: 20084623 DOI: 10.1002/term.258
    Pluripotent stem cells possess the unique property of differentiating into all other cell types of the human body. Further, the discovery of induced pluripotent stem cells (iPSCs) in 2006 has opened up new avenues in clinical medicine. In simple language, iPSCs are nothing but somatic cells reprogrammed genetically to exhibit pluripotent characteristics. This process utilizes retroviruses/lentiviruses/adenovirus/plasmids to incorporate candidate genes into somatic cells isolated from any part of the human body. It is also possible to develop disease-specific iPSCs which are most likely to revolutionize research in respect to the pathophysiology of most debilitating diseases, as these can be mimicked ex vivo in the laboratory. These models can also be used to study the safety and efficacy of known drugs or potential drug candidates for a particular diseased condition, limiting the need for animal studies and considerably reducing the time and money required to develop new drugs. Recently, functional neurons, cardiomyocytes, pancreatic islet cells, hepatocytes and retinal cells have been derived from human iPSCs, thus re-confirming the pluripotency and differentiation capacity of these cells. These findings further open up the possibility of using iPSCs in cell replacement therapy for various degenerative disorders. In this review we highlight the development of iPSCs by different methods, their biological characteristics and their prospective applications in regenerative medicine and drug screening. We further discuss some practical limitations pertaining to this technology and how they can be averted for the betterment of human life.
  5. Das AK
    Indian J Surg, 2009 Aug;71(4):177-81.
    PMID: 23133150 DOI: 10.1007/s12262-009-0059-7
    Critical limb ischaemia is an intractable condition associated with high levels of amputation, leading to a low quality of life and increased morbidity and mortality. It is often not treatable by standard therapeutic modalities. Neoangiogenesis has been proposed as a novel method of treatment of such patients. Vascular endothelial growth factor (VEGF) and cytokine fibroblast growth factor (FGF-1) have been shown to elicit neoangiogenesis. Stem cells are progenitor cells which can differentiate in vivo into different types of cells. Mesenchymal stem cells (MSCs) are a type of adult stem cells which have an immunomodulatory effect. Stem cell therapy has been used in animal studies to improve limb vascularity in rat and rabbit models. Several clinical studies have also validated their use for critical limb ischaemia. However many issues are still unresolved. These include the dosage, delivery and safety issues in relation to stem cell therapy. However stem cells are likely to be an important therapeutic modality to treat critical limb ischaemia in the near future.
  6. Das AK, Bin Abdullah BJ, Dhillon SS, Vijanari A, Anoop CH, Gupta PK
    World J Surg, 2013 Apr;37(4):915-22.
    PMID: 23307180 DOI: 10.1007/s00268-012-1892-6
    BACKGROUND: Critical limb ischemia (CLI) caused by peripheral arterial disease is associated with significant morbidity and mortality. This condition is associated with a 30 % amputation rate as well as mortality levels which might be as high as 25 %. There is no pharmacological therapy available, but several reports have suggested that mesenchymal stem cells (MSCs) may be a useful therapeutic option.
    METHODS: This study, done at a university hospital, evaluated 13 patients for a phase I trial to investigate the safety and efficacy of intra-arterial MSCs in CLI patients. Eight patients with ten affected limbs were recruited for the study. As two patients (three limbs) died of ischemic cardiac events during the 6-month follow-up period, seven limbs were finally evaluated for the study.
    RESULTS: There was significant pain relief. Visual analog scale (VAS) scores decreased from 2.29 ± 0.29 to 0.5 ± 0.34 (p < 0.05), ankle brachial pressure index (ABPI) increased significantly from 0.56 ± 0.02 to 0.67 ± 0.021 (p < 0.01), and transcutaneous oxygen pressure (TcPO2) also increased significantly in the foot from 13.57 ± 3.63 to 38 ± 3.47. Similar improvement was seen in the leg as well as the thigh. There was 86 % limb salvage and six of seven ulcers showed complete or partial healing.
    CONCLUSION: It was concluded that intra-arterial MSCs could be safely administered to patients with CLI and was associated with significant therapeutic benefits.
  7. Das AK, Okita T, Enzo A, Asai A
    Asian Bioeth Rev, 2020 Jun;12(2):103-116.
    PMID: 33717332 DOI: 10.1007/s41649-020-00114-6
    The use of single-use items (SUDs) is now ubiquitous in medical practice. Because of the high costs of these items, the practice of reusing them after sterilisation is also widespread especially in resource-poor economies. However, the ethics of reusing disposable items remain unclear. There are several analogous conditions, which could shed light on the ethics of reuse of disposables. These include the use of restored kidney transplantation and the use of generic drugs etc. The ethical issues include the question of patient safety and the possibility of infection. It is also important to understand the role (or otherwise) of informed consent before reuse of disposables. The widespread practice of reuse may bring down high healthcare costs and also reduce the huge amount of hospital waste that is generated. The reuse of disposables can be justified on various grounds including the safety and the cost effectiveness of this practice.
  8. Das AK
    Indian J Med Ethics, 2020 5 13;V(2):143-148.
    PMID: 32393455 DOI: 10.20529/IJME.2020.032
    Malaysia is a South East Asian country with a racially diverse population. Islam is the state religion and about 60% of the population is Muslim, but the rights of other religious groups are protected by law. The Parti Islam se Malaysia, which has ruled the state of Kelantan since 1999, and believes that Malaysia should be ruled by Sharia law, recently proposed the implementation of Hudud laws in Kelantan. However, the federal government has ruled out its implementation. The suggestion stirred up a controversy among the physician community and the Malaysian Medical Association rejected a proposal by the state's political leadership to utilise the services of qualified surgeons to carry out punitive limb amputations. Several Islamic states such as Sudan, Saudi Arabia, and Iran practice Islamic penal justice, including amputations. The question therefore arises: how should a modern medical practitioner approach this ethical question? This study focuses mainly on Malaysia, but draws upon practices in other Islamic countries also.
  9. Das AK
    Indian J Med Ethics, 2020 5 13;V(2):151.
    PMID: 32393445 DOI: 10.20529/IJME.2020.043
    I would like to thank Dr Adriaan Van Es for his commentary (1) on my article (2). To start with, let me make one thing clear: I am not sure why he thinks that I am condoning the practice of penal amputation. As I clearly state in my conclusion, the arguments that may (or may not) justify penal amputation are abhorrent in liberal societies. We are on the same side here. But what of those who live in less secular societies where religious faith may be unquestioned? In my opinion, van Es has resorted to a typical example of a tortured form of ethical logic (3), which researchers from countries that have different value systems and different problems have deplored, albeit in a different context.
  10. Dutta S, Singh G, Sreejith S, Mamidi MK, Husin JM, Datta I, et al.
    CNS Neurosci Ther, 2013 Jan;19(1):5-11.
    PMID: 23253099 DOI: 10.1111/cns.12027
    Neurodegenerative diseases are devastating because they cause increasing loss of cognitive and physical functions and affect an estimated 1 billion individuals worldwide. Unfortunately, no drugs are currently available to halt their progression, except a few that are largely inadequate. This mandates the search of new treatments for these progressively degenerative diseases. Neural stem cells (NSCs) have been successfully isolated, propagated, and characterized from the adult brains of mammals, including humans. The confirmation that neurogenesis occurs in the adult brain via NSCs opens up fresh avenues for treating neurological problems. The proof-of-concept studies demonstrating the neural differentiation capacity of stem cells both in vitro and in vivo have raised widespread enthusiasm toward cell-based interventions. It is anticipated that cell-based neurogenic drugs may reverse or compensate for deficits associated with neurological diseases. The increasing interest of the private sector in using human stem cells in therapeutics is evidenced by launching of several collaborative clinical research activities between Pharma giants and research institutions or small start-up companies. In this review, we discuss the major developments that have taken place in this field to position stem cells as a prospective candidate drug for the treatment of neurological disorders.
  11. Fui LW, Lok MPW, Govindasamy V, Yong TK, Lek TK, Das AK
    J Tissue Eng Regen Med, 2019 12;13(12):2218-2233.
    PMID: 31648415 DOI: 10.1002/term.2966
    Mesenchymal stem cells (MSCs) transplantation seems to be a promising new therapy for diabetic wound healing (DWH), and currently, arrays of MSCs from various sources ranging from umbilical, adipose to dental sources are available as a treatment modality for this disease. However, it now appears that only a fraction of transplanted cells actually assimilate and survive in host tissues suggesting that the major mechanism by which stem cells participate in tissue repair are most likely related to their secretome level. These include a wide range of growth factors, cytokines, and chemokines, which can be found from the conditioned medium (CM) used to culture the cells. Basic studies and preclinical work confirm that the therapeutic effect of CMs are comparable with the application of stem cells. This review describes in detail the wound healing process in diabetes and the cellular and biological factors that influence the process. Subsequently, through a comprehensive literature search of studies related to wound healing in diabetics, we aim to provide an overview of scientific merits of using MSCs-CM in the treatment of diabetic wound as well as the significant caveats, which restricts its potential use in clinical set-ups. To our best knowledge, this is one of the first review papers that collect the importance of stem cells as an alternative treatment to the DWH. We anticipate that the success of this treatment will have a significant clinical impact on diabetic wounds.
  12. Gopurappilly R, Pal R, Mamidi MK, Dey S, Bhonde R, Das AK
    CNS Neurol Disord Drug Targets, 2011 Sep 1;10(6):741-56.
    PMID: 21838668
    Stroke causes a devastating insult to the brain resulting in severe neurological deficits because of a massive loss of different neurons and glia. In the United States, stroke is the third leading cause of death. Stroke remains a significant clinical unmet condition, with only 3% of the ischemic patient population benefiting from current treatment modalities, such as the use of thrombolytic agents, which are often limited by a narrow therapeutic time window. However, regeneration of the brain after ischemic damage is still active days and even weeks after stroke occurs, which might provide a second window for treatment. Neurorestorative processes like neurogenesis, angiogenesis and synaptic plasticity lead to functional improvement after stroke. Stem cells derived from various tissues have the potential to perform all of the aforementioned processes, thus facilitating functional recovery. Indeed, transplantation of stem cells or their derivatives in animal models of cerebral ischemia can improve function by replacing the lost neurons and glial cells and by mediating remyelination, and modulation of inflammation as confirmed by various studies worldwide. While initially stem cells seemed to work by a 'cell replacement' mechanism, recent research suggests that cell therapy works mostly by providing trophic support to the injured tissue and brain, fostering both neurogenesis and angiogenesis. Moreover, ongoing human trials have encouraged hopes for this new method of restorative therapy after stroke. This review describes up-to-date progress in cell-based therapy for the treatment of stroke. Further, as we discuss here, significant hurdles remain to be addressed before these findings can be responsibly translated to novel therapies. In particular, we need a better understanding of the mechanisms of action of stem cells after transplantation, the therapeutic time window for cell transplantation, the optimal route of cell delivery to the ischemic brain, the most suitable cell types and sources and learn how to control stem cell proliferation, survival, migration, and differentiation in the pathological environment. An integrated approach of cell-based therapy with early-phase clinical trials and continued preclinical work with focus on mechanisms of action is needed.
  13. Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2023 Sep 01;131(9):091903.
    PMID: 37721839 DOI: 10.1103/PhysRevLett.131.091903
    A search for the rare η→μ^{+}μ^{-}μ^{+}μ^{-} double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of 101  fb^{-1}. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the η→μ^{+}μ^{-} decay as normalization, the branching fraction B(η→μ^{+}μ^{-}μ^{+}μ^{-})=[5.0±0.8(stat)±0.7(syst)±0.7(B_{2μ})]×10^{-9} is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions.
  14. Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2024 Jan 26;132(4):041802.
    PMID: 38335361 DOI: 10.1103/PhysRevLett.132.041802
    A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138  fb^{-1} of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section σ(pp→A^{'}→χ_{1}χ_{2}) and the decay branching fraction B(χ_{2}→χ_{1}μ^{+}μ^{-}), where A^{'} is a dark photon and χ_{1} and χ_{2} are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter.
  15. Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2024 Feb 09;132(6):061801.
    PMID: 38394587 DOI: 10.1103/PhysRevLett.132.061801
    The first search for scalar leptoquarks produced in τ-lepton-quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138  fb^{-1}. The reconstructed final state consists of a jet, significant missing transverse momentum, and a τ lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-τ-quark coupling strength.
  16. Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2024 Mar 15;132(11):111901.
    PMID: 38563916 DOI: 10.1103/PhysRevLett.132.111901
    A search is reported for near-threshold structures in the J/ψJ/ψ invariant mass spectrum produced in proton-proton collisions at sqrt[s]=13  TeV from data collected by the CMS experiment, corresponding to an integrated luminosity of 135  fb^{-1}. Three structures are found, and a model with quantum interference among these structures provides a good description of the data. A new structure is observed with a local significance above 5 standard deviations at a mass of 6638_{-38}^{+43}(stat)_{-31}^{+16}(syst)  MeV. Another structure with even higher significance is found at a mass of 6847_{-28}^{+44}(stat)_{-20}^{+48}(syst)  MeV, which is consistent with the X(6900) resonance reported by the LHCb experiment and confirmed by the ATLAS experiment. Evidence for another new structure, with a local significance of 4.7 standard deviations, is found at a mass of 7134_{-25}^{+48}(stat)_{-15}^{+41}(syst)  MeV. Results are also reported for a model without interference, which does not fit the data as well and shows mass shifts up to 150 MeV relative to the model with interference.
  17. Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.
    Phys Rev Lett, 2024 Mar 22;132(12):121901.
    PMID: 38579207 DOI: 10.1103/PhysRevLett.132.121901
    The observation of WWγ production in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of 138  fb^{-1} is presented. The observed (expected) significance is 5.6 (5.1) standard deviations. Events are selected by requiring exactly two leptons (one electron and one muon) of opposite charge, moderate missing transverse momentum, and a photon. The measured fiducial cross section for WWγ is 5.9±0.8(stat)±0.8(syst)±0.7(modeling)  fb, in agreement with the next-to-leading order quantum chromodynamics prediction. The analysis is extended with a search for the associated production of the Higgs boson and a photon, which is generated by a coupling of the Higgs boson to light quarks. The result is used to constrain the Higgs boson couplings to light quarks.
  18. Islam MJ, Saha SK, Das AK, Jahan MS, Pervin S, Karim CF, et al.
    Mymensingh Med J, 2019 Oct;28(4):935-939.
    PMID: 31599264
    Hepatocellular carcinoma (HCC) is an important reason of liver-related death globally. HCC is the fifth most common cancer, the third most common cause for cancer related death in the world and responsible for approximately one million deaths each year. The incidence of HCC is expected to increase in the next two decades, largely due to hepatitis C infection and secondary cirrhosis. We have reported a case of hepatocellular carcinoma in a 56-year-old man with peritoneal metastasis. Diagnostic imaging (Ultra sonogram & CT-Scan) shown: a large hypo density, irregular outline lesion noted in right lower liver, post contrast image shown patchy enhancement of the lesion. His serum Alpha-Feto Protein (AFP) level was very high with elevated serum alanine amino transaminase (ALT) enzyme and prothrombin time. Histopathological (microscopic) features are compatible with Hepatocellular carcinoma. His Hepatitis C viral DNA load e.g., core protein variants and genotype 1, have been reported. The patient was treated by surgical resection followed by conservative treatment includes sorafenib & interferon alpha. This case report aims to outlines the epidemiology of HCC in chronic HCV, risk factors and pathophysiology that contribute to this disease process, related pathophysiology of patient's clinical features, screening recommendations, and the available statistics on the impact of new direct-acting antiviral treatment on the development on HCC.
  19. Islam MN, Liza AA, Khatun ML, Faruk MO, Das AK, Dey M, et al.
    Glob Chall, 2021 Sep;5(9):2100002.
    PMID: 34504715 DOI: 10.1002/gch2.202100002
    This study investigates the efficacy of chemically modified bone adhesive as a formaldehyde-free binder for wood-based industries. Two different types of adhesive are formulated after chemical modification of bone powder using sulfuric acid (0.5 m) and polyvinyl acetate (PVA). Gel time, solid content, Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), viscosity, and single lap joint test for shear strength are analyzed in order to assess the adhesive properties. To analyze the efficacy of the formulated adhesive, particleboards are fabricated using boiled and unboiled sugarcane bagasse. The physical and mechanical properties of the fabricated panels are measured following ASTM standards. It is found that adhesive Type C (T-C) has the shortest gel time of 4.2 min for the highest shear strength, i.e., 5.31 MPa. The particleboard (BTC-2) fabricated using T-C adhesive shows a highest density of 0.73 g cm-3, a modulus of elasticity (MOE) of 1975 N mm-2, and a modulus of rupture (MOR) of 11.80 N mm-2. The dimensional stability of the fabricated particleboards does not follow the standard requirements; however, further study might be helpful for using the chemically modified bone adhesive as a biobased adhesive.
  20. Kalra S, Bajaj S, Sharma SK, Priya G, Baruah MP, Sanyal D, et al.
    Diabetes Ther, 2020 Mar;11(3):585-606.
    PMID: 31981212 DOI: 10.1007/s13300-020-00764-7
    AIM: To develop an evidence-based expert group opinion on the role of insulin motivation to overcome insulin distress during different stages of insulin therapy and to propose a practitioner's toolkit for insulin motivation in the management of diabetes mellitus (DM).

    BACKGROUND: Insulin distress, an emotional response of the patient to the suggested use of insulin, acts as a major barrier to insulin therapy in the management of DM. Addressing patient-, physician- and drug-related factors is important to overcome insulin distress. Strengthening of communication between physicians and patients with diabetes and enhancing the patients' coping skills are prerequisites to create a sense of comfort with the use of insulin. Insulin motivation is key to achieving targeted goals in diabetes care. A group of endocrinologists came together at an international meeting held in India to develop tool kits that would aid a practitioner in implementing insulin motivation strategies at different stages of the journey through insulin therapy, including pre-initiation, initiation, titration and intensification. During the meeting, emphasis was placed on the challenges and limitations faced by both physicians and patients with diabetes during each stage of the journey through insulinization.

    REVIEW RESULTS: After review of evidence and discussions, the expert group provided recommendations on strategies for improved insulin acceptance, empowering behavior change in patients with DM, approaches for motivating patients to initiate and maintain insulin therapy and best practices for insulin motivation at the pre-initiation, initiation, titration and intensification stages of insulin therapy.

    CONCLUSIONS: In the management of DM, bringing in positive behavioral change by motivating the patient to improve treatment adherence helps overcome insulin distress and achieve treatment goals.

Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links