Displaying publications 41 - 60 of 559 in total

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  1. Kumar S, Yushak AW, Gul YA
    Med J Malaysia, 2004 Aug;59(3):425-7.
    PMID: 15727393
    Haemangiopericytoma (HPC) is a rare tumour with a predilection for the central nervous system. Though previously thought to originate from the meninges and ventricular walls, HPC's are currently accepted as distinct mesenchymal neoplasms unrelated to meningiomas. Haemangiopericytomas have been previously reported to be associated with the production of insulin like growth factor II (IGF-II) and hypoglycaemia. A case of a 61-year-old poorly controlled diabetic lady with a rare presentation of an abdominal haemangiopericytoma is discussed. A laparoscopic assisted resection of the massive lobulated tumour arising from the parietal peritoneum with dense attachment to the diaphragm and the liver was performed with an uncomplicated postoperative recovery. Control of the patient's diabetes improved dramatically following surgery and the rare association of hyperglycaemia and HPC, which has not been previously described, is elaborated upon in this report.
  2. Raman K, Kumar S, Chye TT
    Parasitol Res, 2016 Jan;115(1):391-6.
    PMID: 26481491 DOI: 10.1007/s00436-015-4760-0
    Blastocystis sp., an intestinal organism is known to cause diarrhea with metronidazole regarded as the first line of treatment despite reports of its resistance. The conflicting reports of variation in drug treatment have been ascribed to subtype differences. The present study evaluated in vitro responses due to metronidazole on ST3 isolated from three symptomatic and asymptomatic patients, respectively. Symptomatic isolates were obtained from clinical patients who showed symptoms such as diarrhea and abdominal bloating. Asymptomatic isolates from a stool survey carried out in a rural area. These patients had no other pathogens other than Blastocystis. Ultrastructural studies using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed drug-treated ST3 from symptomatic patients were irregular and amoebic with surface showing high-convoluted folding when treated with metronidazole. These organisms had higher number of mitochondrion-like organelle (MLO) with prominent cristae. However, the drug-treated ST3 from asymptomatic persons remained spherical in shape. Asymptomatic ST3 showed increase in the size of its central body with the MLO located at the periphery.
  3. Mohamed R, Pal Singh S, Kumar S, Lavin MF
    Biochem Biophys Res Commun, 1987 Nov 30;149(1):233-8.
    PMID: 2825700
    DNA topoisomerase type I and II activities were determined by serial dilution in nuclear extracts from control and ataxia-telangiectasia lymphoblastoid cells. Topoisomerase I activity, assayed by relaxation of supercoiled plasmid DNA, was found to be approximately the same in both cell types. In order to remove interference from topoisomerase I, the activity of topoisomerase II was measured by the unknotting of knotted P4 phage DNA in the presence of ATP. The activity of topoisomerase II was markedly reduced in two ataxia-telangiectasia cell lines, AT2ABR and AT8ABR, compared to controls. This reduction in activity was detected with increasing concentration of protein and in time course experiments at a single protein concentration. A third cell line, AT3ABR, did not have a detectably lower activity of topoisomerase II when assayed under these conditions. The difference in topoisomerase II activity in the ataxia-telangiectasia cell lines examined may reflect to some extent the heterogeneity observed in this syndrome.
  4. Mathavan S, Kue CS, Kumar S
    Genomics Inform, 2021 Mar;19(1):e4.
    PMID: 33840168 DOI: 10.5808/gi.20062
    Lip and oral cavity cancer, which can occur in any part of the mouth, is the 11th most common type of cancer worldwide. The major obstacles to patients' survival are the poor prognosis, lack of specific biomarkers, and expensive therapeutic alternatives. This study aimed to identify the main genes and pathways associated with lip and oral cavity carcinoma using network analysis and to analyze its molecular mechanism and prognostic significance further. In this study, 472 genes causing lip and oral cavity carcinoma were retrieved from the DisGeNET database. A protein-protein interaction network was developed for network analysis using the STRING database. VEGFA, IL6, MAPK3, INS, TNF, MAPK8, MMP9, CXCL8, EGF, and PTGS2 were recognized as network hub genes using the maximum clique centrality algorithm available in cytoHubba, and nine potential drug candidates (ranibizumab, siltuximab, sulindac, pomalidomide, dexrazoxane, endostatin, pamidronic acid, cetuximab, and apricoxib) for lip and oral cavity cancer were identified from the DGIdb database. Gene enrichment analysis was also performed to identify the gene ontology categorization of cellular components, biological processes, molecular functions, and biological pathways. The genes identified in this study could furnish a new understanding of the underlying molecular mechanisms of carcinogenesis and provide more reliable biomarkers for early diagnosis, prognostication, and treatment of lip and oral cavity cancer.
  5. Huang J, Kumar S, Hu C
    Front Psychol, 2021;12:696552.
    PMID: 34497560 DOI: 10.3389/fpsyg.2021.696552
    The tremendous development of the Internet enables people to present themselves freely. Some people may reconstruct their identity on the Internet to build an online identity that is partly or even completely different from their real identity in the offline world. Given that research on online identity reconstruction is fragmented, it is important to evaluate the current state of the literature. In this paper, a review of literature related to online identity reconstruction was conducted. This study summarized the theoretical and methodological preferences of relevant research. In addition, it elaborated why and how people engage in online identity reconstruction. The predictors and effects of online identity reconstruction were also discussed. The results of this study provided an overview of the thematic patterns of existing research. This review also identified current research gaps and recommended possible directions for future studies.
  6. Hu C, Kumar S, Huang J, Ratnavelu K
    PLoS One, 2017;12(4):e0175623.
    PMID: 28399153 DOI: 10.1371/journal.pone.0175623
    In face-to-face communications, to avoid sanctions and disapproval from others, people are more likely to hide negative aspects of their true self (such as socially undesirable personalities, minds, beliefs and consciousness) to avoid conflict with social norms and laws. The anonymity of cyberspace provides people a unique environment to behave more freely and openly with less restraint from the real word. Existing research related to online true self expression has mainly explored true self as an independent aspect of self. Regarding true self as a two-dimensional concept, this study investigates true self from the perspective of individuals' self-guide and identity reconstruction in both online and offline world. Using qualitative research methods, the current study investigates 57 participants through interviews and questionnaires. Content analysis reveals four factors that motivate people to express more true self (especially negative true self) when reconstructing their online identity and involve true self as a part of their self-guide in anonymous environment. By incorporating true self as an important part of individuals' self-guide and identity online, the current study advances self-discrepancy theory, making it more comprehensive for cyberspace. The results are also interpreted based on self-determination theory. The theoretical contributions of this study are discussed and practical implications are also presented.
  7. Kumar SK, Trujillo PB, Ucros GR
    Med J Malaysia, 2017 04;72(2):138-140.
    PMID: 28473683
    Worldwide breast cancer remains as the most common malignancy in women and the numbers who form a subgroup with dense breast parenchyma are substantial. In addition to mammography, the adjuncts used for further evaluation of dense breasts have been anatomically based modalities such as ultrasound and magnetic resonance imaging. The practice of functionally based imaging of breasts is relatively new but has undergone rapid progress over the past few years with promising results. The value of positron emission mammography is demonstrated in patients with dense breasts and mammographically occult disease.
  8. Rajamanikam A, Kumar S, Samudi C, Kudva M
    Parasitol Res, 2018 Aug;117(8):2585-2590.
    PMID: 29872961 DOI: 10.1007/s00436-018-5948-x
    Blastocystis sp. is a gastrointestinal (GI) protozoan parasite reported to cause non-specific GI symptoms including diarrhea, flatulence, abdominal pain, and nausea. Complete eradication of Blastocystis sp. is rather challenging even with the drug of choice, i.e., metronidazole. Here, we report on two Blastocystis sp.-infected individuals, who presented increased parasite load and exacerbated symptoms upon treatment with the usual recommended dosage and regime of metronidazole. The two studies uniquely demonstrate for the first time a cyst count as high as fivefold more than the original cyst count before treatment and show an exacerbation of GI symptoms despite treatment. The study provides additional support in recognizing metronidazole resistance in Blastocystis sp. and its consequences towards the pathogenicity of the parasite.
  9. Bera H, Nadimpalli J, Kumar S, Vengala P
    Int J Biol Macromol, 2017 Nov;104(Pt A):1229-1237.
    PMID: 28688948 DOI: 10.1016/j.ijbiomac.2017.07.027
    Flurbiprofen (FLU), a non-steroidal anti-inflammatory drug, exhibits limited clinical response due to its poor physicochemical properties. This study aimed at developing reliable drug carriers for intrgastric FLU delivery with a view to improve biopharmaceutical characteristics of drug and modulate its release in a controlled manner. In this context, FLU-loaded kondogogu gum (KG)-Zn(+2)-low methoxyl (LM) pectinate emulgel matrices reinforced with calcium silicate (CS) were accomplished by ionotropic gelation technique employing zinc acetate as cross-linker and characterized for their in vitro performances. All the formulations demonstrated excellent drug encapsulation efficiency (DEE, 46-87%) and sustained drug release behavior (Q7h, 70-91%). These quality attributes were remarkably influenced by polymer-blend (LM pectin:KG) ratios, low-density oil types and CS inclusion. The drug release profile of the FLU-loaded optimized matrices (F-7) was best fitted in Korsmeyer-Peppas model with Fickian diffusion driven mechanism. It also conferred excellent in vitro gastroretention capabilities. Moreover, the drug-excipient compatibility, alteration of crystallinity and thermal behavior of drug and surface morphology of matrices were evidenced with the results of FTIR, XRD, DSC and SEM analyses, respectively. Thus, the newly developed matrices are appropriate for sustained intragastric FLU delivery and simultaneous zinc supplementation for effective inflammation and arthritis management.
  10. Sharma G, Vasanth Kumar S, Wahab HA
    J Biomol Struct Dyn, 2018 01;36(1):233-242.
    PMID: 28013578 DOI: 10.1080/07391102.2016.1274271
    A series of dimeric naphthoquinones containing natural 2-hydroxy-1-4-naphthoquinone moiety was designed, synthesized, and evaluated against neuraminidase of H5N1 virus. p-hydroxy derivatives showed higher inhibition when compared to p-halogenated compounds. Molecular docking studies conducted with H5N1 neuraminidase clearly demonstrated different binding modes of the most active compound onto the open and closed conformations of loop 150. The results thus provide not only evidences of a novel scaffold evaluated as inhibitor, but also a rational explanation involving molecular modeling and the role of loop 150 in the binding.
  11. Kumar S, Thomas BS, Gupta K, Guddattu V, Alexander M
    Niger J Clin Pract, 2018 Aug;21(8):1029-1033.
    PMID: 30074006 DOI: 10.4103/njcp.njcp_341_17
    Aim and objectives: The aim and the objectives were. (1) to assess the efficacy of a desensitizing toothpaste containing 8.0% arginine-calcium carbonate (Colgate® Sensitive Pro-Relief™), (2) to assess the efficacy of a desensitizing toothpaste containing 8.0% arginine-calcium carbonate (Colgate® Sensitive Pro-Relief™) used in combination with iontophoresis, and (3) to compare the effectiveness of the above methods.

    Subjects and Methods: Two groups of 40 patients each having dentinal hypersensitivity were treated using 8% proarginine and iontophoresis. The patients were recalled after 1, 2, and 4 weeks. The scores were tabulated and the results were analyzed using SPSS statistical software.

    Results: Visual analog scale between the two groups showed a significant difference from the 1st week till the 4th week. ANOVA values showed the reduction in the dentinal hypersensitivity in Group 2 using the iontophoresis along with the 8.0% arginine-calcium carbonate toothpaste. The Cochran-Mantel-Haenszel correlation test of the Schiff's dentinal hypersensitivity cross-tabulation showed P < 0.001 which was statistically significant reduction after the 4th week following the application of 8.0% arginine-calcium carbonate along with iontophoresis.

    Conclusion: Iontophoresis, when used along with Colgate® Sensitive Pro-Relief™ toothpaste, can provide additional benefit as this provides a better sealing effect.

  12. Kumar S, Neven LG, Yee WL
    J Econ Entomol, 2014 Jun;107(3):1032-44.
    PMID: 25026662
    Sweet cherries, Prunus avium (L.) L., grown in the western United States are exported to many countries around the world. Some of these countries have enforced strict quarantine rules and trade restrictions owing to concerns about the potential establishment and subsequent spread of western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), a major quarantine pest of sweet cherry. We used 1) niche models (CLIMEX and MaxEnt) to map the climatic suitability, 2) North Carolina State University-Animal and Plant Health Inspection Service Plant Pest Forecasting System to examine chilling requirement, and 3) host distribution and availability to assess the potential for establishment of R. indifferens in areas of western North America where it currently does not exist and eight current or potential fresh sweet cherry markets: Colombia, India, Indonesia, Malaysia, Taiwan, Thailand, Venezuela, and Vietnam. Results from niche models conformed well to the current distribution of R. indifferens in western North America. MaxEnt and CLIMEX models had high performance and predicted climatic suitability in some of the countries (e.g., Andean range in Colombia and Venezuela, northern and northeastern India, central Taiwan, and parts of Vietnam). However, our results showed no potential for establishment of R. indifferens in Colombia, Indonesia, Malaysia, Taiwan, Thailand, Venezuela, and Vietnam when the optimal chilling requirement to break diapause (minimum temperature < or = 3 degree C for at least 15 wk) was used as the criterion for whether establishment can occur. Furthermore, these countries have no host plant species available for R. indifferens. Our results can be used to make scientifically informed international trade decisions and negotiations by policy makers.
  13. Mukherjee D, Kumar S, Donthu N, Pandey N
    Manag Int Rev, 2021;61(5):599-642.
    PMID: 34658534 DOI: 10.1007/s11575-021-00454-x
    The Management International Review (MIR) celebrated its 60th anniversary in 2020. In commemoration of this event, we use a bibliometric analysis to present a retrospective on the journal by analyzing its content for the years between 2006 and 2020. We find that the collaboration culture in MIR has risen over time with the increase in the median size of author teams. Moreover, the collaboration network has become more global over time. The methodology used in the journal is predominantly empirical and quantitative with archival data sources most commonly used. The bibliographic coupling of the MIR corpus reveals that the major themes in the journal revolve around "culture," "emerging economies," "innovation, knowledge transfer, and absorptive capacity," "internationalization process," "culture and entry modes," and "internationalization and performance." A comparison with other leading international business journals provides distinct pathways in which MIR may continue to grow. Finally, it is important to note that while the share of conceptual studies has decreased significantly in the last 15 years, the MIR editors want to see more novel and theoretically grounded conceptual articles in the journal.
  14. Mohd-Zain Z, Mohd-Nawi SFA, Adnan A, Kumar S
    Malays J Pathol, 2017 Aug;39(2):115-122.
    PMID: 28866692 MyJurnal
    BACKGROUND: HIV-infected patients pose a high risk of contracting skin and soft tissue infections caused by Staphylococcus aureus. Those who are colonized with methicillin-resistant S. aureus (MRSA) that carry Panton-Valentine leukocidin (PVL) are predisposed to severe infections that could lead to necrotic skin infections. However the association of S. aureus specifically methicillin sensitive S. aureus carrying PVL gene in HIV patients has not been widely reported. Here, we study the prevalence and the molecular epidemiology of PVL-producing S. aureus in HIV-infected patients.

    METHODS: Swabs from four body sites of 129 HIV-infected patients were cultured for S. aureus and identified by standard microbiological procedures. The isolates were subjected to antimicrobial susceptibility testing by disk diffusion against penicillin, erythromycin, clindamycin, and cotrimoxazole. PCR was used to detect the PVL gene and genetic relationship between the isolates was determined by using pulse field gel electrophoresis.

    RESULTS: A total of 51 isolates of S. aureus were obtained from 40 (31%) of the patients. The majority (43.1%) of the isolates were obtained from the anterior nares. Thirteen (25.5%) of all the isolates were resistant to more than one category of antibiotics, with one isolate identified as MRSA. Thirty-eight (74.5%) isolates (including the MRSA isolate) carried PVL gene where the majority (44.7%) of these isolates were from the anterior nares. A dendogram revealed that the isolates were genetically diverse with 37 distinct pulsotypes clustered in 11 groups.

    CONCLUSION: S. aureus obtained from multiple sites of the HIV patients were genetically diverse without any clonality observed.

  15. Ding SLS, Kumar S, Mok PL
    Int J Mol Sci, 2017 Jul 28;18(8).
    PMID: 28788088 DOI: 10.3390/ijms18081406
    The use of multipotent mesenchymal stem cells (MSCs) has been reported as promising for the treatment of numerous degenerative disorders including the eye. In retinal degenerative diseases, MSCs exhibit the potential to regenerate into retinal neurons and retinal pigmented epithelial cells in both in vitro and in vivo studies. Delivery of MSCs was found to improve retinal morphology and function and delay retinal degeneration. In this review, we revisit the therapeutic role of MSCs in the diseased eye. Furthermore, we reveal the possible cellular mechanisms and identify the associated signaling pathways of MSCs in reversing the pathological conditions of various ocular disorders such as age-related macular degeneration (AMD), retinitis pigmentosa, diabetic retinopathy, and glaucoma. Current stem cell treatment can be dispensed as an independent cell treatment format or with the combination of other approaches. Hence, the improvement of the treatment strategy is largely subjected by our understanding of MSCs mechanism of action.
  16. Kumar S, Subramaniam G, Karuppanan K
    J Med Virol, 2023 Jan;95(1):e27894.
    PMID: 35637363 DOI: 10.1002/jmv.27894
  17. Hong J, Crawford K, Cavanagh E, da Silva Costa F, Kumar S
    PMID: 37820083 DOI: 10.1002/uog.27513
    OBJECTIVE: To assess the association between placental biomarkers (placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio) and fetoplacental Dopplers - Umbilical Artery Pulsatility Index (UA PI) and Uterine Artery Pulsatility Index (UtA PI) in various combinations for the likelihood of preterm birth (PTB) in women with fetal growth restriction (FGR).

    METHODS: A prospective cohort study of pregnancies complicated by FGR. Maternal serum PlGF levels, sFlt-1/PlGF ratio, UA PI and UtA PI were measured at 4-weekly intervals from recruitment to delivery. Harrell's concordance statistic was used to evaluate various combinations of placental biomarkers and fetoplacental Dopplers to ascertain the ideal combination to predict PTB (<37 weeks). Multivariable Cox regression was used as time-varying covariates.

    RESULTS: There were 320 pregnancies in the study cohort - 179 (55.9%) were FGR and 141 (44.1%) were AGA. In the FGR cohort, both low PlGF levels and elevated sFlt-1/PlGF ratio significantly affected time to PTB. Low PlGF was a better predictor of PTB than either sFlt-1/PlGF ratio or combination of PlGF and sFlt-1/PlGF ratio (Harrell's C 0.81, 0.79, 0.75 respectively). Similarly, although both UA PI and UtA PI >95th centile for gestation significantly affected the time to PTB, in combination, they were better predictors than either measure alone (Harrell's C 0.82, 0.75, 0.76 respectively). The predictive utility was highest when PlGF <100ng/L, UA PI and UtA PI >95th centile was combined (Harrell's C 0.88) (HR 32.99 95% CI 10.74, 101.32).

    CONCLUSIONS: Low maternal PlGF levels (<100ng/L) and abnormal fetoplacental Dopplers (UA PI and UtA PI >95th centile) in combination have greatest predictive utility for PTB in pregnancies complicated with FGR and may help guide clinical management of these complex pregnancies. This article is protected by copyright. All rights reserved.

  18. Chen L, Kumar S, Wu H
    Arch Microbiol, 2023 Oct 20;205(11):356.
    PMID: 37863957 DOI: 10.1007/s00203-023-03699-2
    The emergence and transmission of antibiotic resistance is a global public health crisis with significant burden on healthcare systems, resulting in high mortality and economic costs. In 2019, almost five million deaths were associated with drug-resistant infections, and if left unchecked, the global economy could lose $100 trillion by 2050. To effectively combat this crisis, it is essential for all countries to understand the current situation of antibiotic resistance. In this review, we examine the current driving factors leading to the crisis, impact of critical superbugs in three regions, and identify novel mechanisms of antibiotic resistance. It is crucial to monitor the phenotypic characteristics of drug-resistant pathogens and describe the mechanisms involved in preventing the emergence of cross-resistance to novel antimicrobials. Additionally, maintaining an active pipeline of new antibiotics is essential for fighting against diverse antibiotic-resistant pathogens. Developing antibacterial agents with novel mechanisms of action is a promising way to combat increasing antibiotic-resistant pathogens.
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