| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
|
|
| 2. |
- Bednar, Peter, et al.
(författare)
-
Business Systems Analysis as Research
- 2011
-
Ingår i: Proceedings of 10th European Conference onResearch Methodology for Business and Management Studies. - 9781908272027 ; , s. 51-59
-
Konferensbidrag (refereegranskat)abstract
- A business analyst who commences an investigation into design requirements for a new work system probably does not ‘label’ her inquiry process as research. However, a research perspective is needed if a productive learning spiral is to be established in which ‘useful’ systems can be created. Systematic, collaborative inquiry adopting an complex, open systems perspective is required in order to establish bases for greater understanding of contextually dependent and individual conceptions of business situations. A professional analyst will recognize that she is attempting to facilitate and engage support for an organizational change process. Similarly, a researcher must recognize that her presence is not ‘neutral’ and take responsibility for the intervention that her actions constitute. This paper discusses the nature of business systems analysis and its relationship(s) to critically informed research processes. It examines research within complex open systems such as business organisations, taking into account the kinds of logic required when researching messy, uncertain problem spaces.
|
|
| 3. |
- Ottmann, Oliver, et al.
(författare)
-
Dasatinib induces rapid hematologic and cytogenetic responses in adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia with resistance or intolerance to imatinib : interim results of a phase 2 study
- 2007
-
Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 110:7, s. 2309-2315
-
Tidskriftsartikel (refereegranskat)abstract
- Patients with Philadelphia (Ph) chromosome-positive acute lymphoblastic leukemia (ALL) have a rapid disease course and a poor prognosis. Dasatinib, a novel, oral, multitargeted kinase inhibitor of BCR-ABL and SRC family kinases, has previously induced responses in patients with imatinib-resistant or -intolerant Ph-positive ALL. We present the interim results of a phase 2 study designed to further assess the efficacy, safety, and tolerability of dasatinib 140 mg in this patient population (n = 36). With a minimum follow-up of 8 months, treatment with dasatinib resulted in substantial hematologic and cytogenetic response rates. Major hematologic responses were achieved in 42% (15/36) of patients, 67% of whom remained progression-free. Complete cytogenetic responses were attained by 58% (21/36) of patients. The presence of BCR-ABL mutations conferring imatinib resistance did not preclude a response to dasatinib. Dasatinib was also tolerable, with 6% (2/36) of patients discontinuing therapy as a result of study-drug toxicity. Most adverse events (AEs) were grade 1 or 2; febrile neutropenia was the most frequent severe AE, but this and other cytopenias were manageable with dose reduction. Dasatinib represents a safe and effective treatment option and an important therapeutic advance for patients with Ph-positive ALL. This trial was registered at www.clinicaltrials.gov as #CA180015.
|
|
| 4. |
- Vimali, Jaisheela, et al.
(författare)
-
Chronic Viral Infection Compromises the Quality of Circulating Mucosal-Associated Invariant T Cells and Follicular T Helper Cells via Expression of Inhibitory Receptors
- 2024
-
Ingår i: FRONTIERS IN BIOSCIENCE-LANDMARK. - : IMR PRESS. - 2768-6701. ; 29:3
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Chronic viral infection results in impaired immune responses rendering viral persistence. Here, we compared the quality of T-cell responses among chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV)-infected individuals by examining the levels of expression of selected immune activation and exhaustion molecules on circulating MAIT cells and Tfh cells. Methods: Cytokines were measured using a commercial Bio-plex Pro Human Cytokine Grp I Panel 17-plex kit (BioRad, Hercules, CA, USA). Inflammation was assessed by measuring an array of plasma cytokines, and phenotypic alterations in CD4(+) T cells including circulating Tfh cells, CD8(+) T cells, and TCR iV alpha 7.2(+) MAIT cells in chronic HBV, HCV, and HIV-infected patients and healthy controls. The cells were characterized based on markers pertaining to immune activation (CD69, ICOS, and CD27) proliferation (Ki67), cytokine production (TNF-alpha, IFN-gamma) and exhaustion (PD-1). The cytokine levels and T cell phenotypes together with cell markers were correlated with surrogate markers of disease progression. Results: The activation marker CD69 was significantly increased in CD4(+hi) T cells, while CD8(+) MAIT cells producing IFN-gamma were significantly increased in chronic HBV, HCV and HIV infections. Six cell phenotypes, viz., TNF-alpha(+)CD4(+lo) T cells, CD69(+)CD8(+) T cells, CD69(+)CD4(+) MAIT cells, PD-1(+)CD4(+hi) T cells, PD-1(+)CD8(+) T cells, and Ki67(+)CD4(+) MAIT cells, were independently associated with decelerating the plasma viral load (PVL). TNF-alpha levels showed a positive correlation with increase in cytokine levels and decrease in PVL. Conclusion: Chronic viral infection negatively impacts the quality of peripheral MAIT cells and Tfh cells via differential expression of both activating and inhibitory receptors.
|
|
| 5. |
- Vimali, Jaisheela, et al.
(författare)
-
Plasma interleukin-7 correlation with human immunodeficiency virus RNA and CD4+T cell counts, and interleukin-5 with circulating hepatitis B virus DNA may have implications in viral control
- 2022
-
Ingår i: Frontiers in Medicine. - : Frontiers Media SA. - 2296-858X. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Chronic viral infections represent a leading cause of global morbidity and mortality. Chronic HBV, HCV, and HIV infections result in cytokine perturbations that may hold key implications in understanding the complex disease mechanisms driving virus persistence and/or resolution. Here, we determined the levels of various plasma cytokines using a commercial Bio-Plex Luminex cytokine array in chronic HBV (n = 30), HCV (n = 15), and HIV (n = 40) infections and correlated with corresponding plasma viral loads (PVLs) and liver parameters. We observed differential perturbations in cytokine profiles among the study groups. The cytokines levels positively correlated with PVL and liver transaminases. The monocyte-derived cytokines viz., MIP-1 beta, IL-8, and TNF-alpha, and Th2 cytokines like IL-4, IL-5, and IL-13 showed a better correlation with liver enzymes as compared to their corresponding PVLs. Our investigation also identified two cytokines viz., IL-5 and IL-7 that inversely correlated with HBV DNA and HIV PVLs, respectively. Regression analysis adjusted for age showed that every increase of IL-5 by one unit was associated with a reduction in HBV PVL by log(10) 0.4, whereas, every elevation by a unit of IL-7 was associated with decreased HIV PVL by log(10) 2.5. We also found that IL-7 levels correlated positively with absolute CD4+ T cell counts in HIV-infected patients. We concluded that plasma IL-5 and IL-7 may likely have a key role on viral control in HBV and HIV infections, respectively. A noteworthy increase in cytokines appears to bear protective and pathological significance, and indeed is reflective of the hosts versatile immune armory against viral persistence.
|
|
| 6. |
- Vimali, Jaisheela, et al.
(författare)
-
Surrogate Biomarkers of Disease Progression in Human Pegivirus Seropositive Human Immunodeficiency Virus-Infected Individuals
- 2023
-
Ingår i: Viral immunology. - : MARY ANN LIEBERT, INC. - 0882-8245 .- 1557-8976. ; 36:1, s. 55-62
-
Tidskriftsartikel (refereegranskat)abstract
- Scientific observations indicate that an actively prevailing systemic condition could alleviate the pathology of another disease. Human pegivirus (HPgV), a highly ubiquitous flavivirus is believed to be associated with slow human immunodeficiency virus (HIV) disease progression, and has seldom been linked to hepatic pathology. In this study, we investigated whether HPgV seropositivity had any impact on surrogate markers of HIV disease progression in a cohort of HIV-infected HPgV seropositive (n = 28) and seronegative (n = 12) individuals who were prospectively evaluated for absolute CD4+ T cell counts, plasma viral load (PVL), liver enzymes, and plasma cytokine levels. The HIV PVL was relatively lower in HPgV seropositive than in HPgV seronegative HIV-infected subjects. Clinical markers of hepatic injury were significantly low among HPgV seropositive HIV-infected participants. HPgV seropositive individuals showed significantly higher levels of interleukin-7 (IL-7), and although not significant, the levels of IL-6 were lower among HPgV seropositive subjects. Spearman correlation analysis showed that the absolute CD4+T cell count was inversely correlated with HIV PVL. Exposure to HPgV appears to have a positive prognostic impact on the levels of surrogate biomarkers of HIV disease progression.
|
|
