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result(s) for
"Lysak, Daniel"
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Exploring Proton-Only NMR Experiments and Filters for Daphnia In Vivo: Potential and Limitations
2023
Environmental metabolomics provides insight into how anthropogenic activities have an impact on the health of an organism at the molecular level. Within this field, in vivo NMR stands out as a powerful tool for monitoring real-time changes in an organism’s metabolome. Typically, these studies use 2D 13C-1H experiments on 13C-enriched organisms. Daphnia are the most studied species, given their widespread use in toxicity testing. However, with COVID-19 and other geopolitical factors, the cost of isotope enrichment increased ~6–7 fold over the last two years, making 13C-enriched cultures difficult to maintain. Thus, it is essential to revisit proton-only in vivo NMR and ask, “Can any metabolic information be obtained from Daphnia using proton-only experiments?”. Two samples are considered here: living and whole reswollen organisms. A range of filters are tested, including relaxation, lipid suppression, multiple-quantum, J-coupling suppression, 2D 1H-1H experiments, selective experiments, and those exploiting intermolecular single-quantum coherence. While most filters improve the ex vivo spectra, only the most complex filters succeed in vivo. If non-enriched organisms must be used, then, DREAMTIME is recommended for targeted monitoring, while IP-iSQC was the only experiment that allowed non-targeted metabolite identification in vivo. This paper is critically important as it documents not just the experiments that succeed in vivo but also those that fail and demonstrates first-hand the difficulties associated with proton-only in vivo NMR.
Journal Article
Exploring the Potential of Broadband Complementary Metal Oxide Semiconductor Micro-Coil Nuclear Magnetic Resonance for Environmental Research
by
Lysak, Daniel H.
,
Wolff, William W.
,
Simpson, Andre J.
in
Animals
,
Brassica - chemistry
,
CMOS
2023
With sensitivity being the Achilles’ heel of nuclear magnetic resonance (NMR), the superior mass sensitivity offered by micro-coils can be an excellent choice for tiny, mass limited samples such as eggs and small organisms. Recently, complementary metal oxide semiconductor (CMOS)-based micro-coil transceivers have been reported and demonstrate excellent mass sensitivity. However, the ability of broadband CMOS micro-coils to study heteronuclei has yet to be investigated, and here their potential is explored within the lens of environmental research. Eleven nuclei including 7Li, 19F, 31P and, 205Tl were studied and detection limits in the low to mid picomole range were found for an extended experiment. Further, two environmentally relevant samples (a sprouting broccoli seed and a D. magna egg) were successfully studied using the CMOS micro-coil system. 13C NMR was used to help resolve broad signals in the 1H spectrum of the 13C enriched broccoli seed, and steady state free precession was used to improve the signal-to-noise ratio by a factor of six. 19F NMR was used to track fluorinated contaminants in a single D. magna egg, showing potential for studying egg–pollutant interactions. Overall, CMOS micro-coil NMR demonstrates significant promise in environmental research, especially when the future potential to scale to multiple coil arrays (greatly improving throughput) is considered.
Journal Article
Comparable outcomes of BTK inhibitors and fixed-duration venetoclax plus rituximab in second-line treatment of chronic lymphocytic leukaemia: a real-world analysis by the Czech CLL study group
by
Smolej, Lukáš
,
Brejcha, Martin
,
Móciková, Heidi
in
Acalabrutinib
,
Adenine - administration & dosage
,
Adenine - analogs & derivatives
2026
In relapsed/refractory (RR) chronic lymphocytic leukaemia (CLL), Bruton tyrosine kinase inhibitors (BTKi) are administered as monotherapy until disease progression. In contrast, venetoclax, a B-cell lymphoma 2 (BCL-2) protein inhibitor, is typically combined with rituximab (VenR) as a time-limited regimen. To date, neither randomized nor retrospective trials have directly compared these approaches in RR CLL, and only limited data are available comparing venetoclax plus obinutuzumab (VenObi) to BTKi in the first-line setting. We retrospectively analysed 352 patients receiving second-line therapy: 93 VenR and 259 BTKi (ibrutinib:
n
= 222; acalabrutinib:
n
= 37). Baseline characteristics were well balanced, except for a higher incidence of
TP53
mutation and trisomy 12 in BTKi-treated patients. At a median follow-up of 13.8 months (VenR) and 22.1 months (BTKi), 12-month progression-free survival (PFS) and overall survival (OS) were comparable (PFS: 85.1% vs. 82.2%,
p
= 0.265; OS: 87.6% vs. 88.4%,
p
= 0.291). Estimated median PFS (45.4 vs. 37.9 months,
p
= 0.265) and OS (83.6 vs. 74.2 months,
p
= 0.291) also showed no significant differences between the VenR and BTKi cohorts. Treatment discontinuation due to adverse events before month 24 was more frequent with BTKi (22.5% with VenR vs. 34.3% with BTKi), primarily due to infections (10.6% vs. 28.6%) and disease progression (14.3% vs. 22.5%). These preliminary data suggest comparable outcomes and manageable toxicity profiles for both regimens.
Journal Article
FoxO1/Rictor axis induces a nongenetic adaptation to ibrutinib via Akt activation in chronic lymphocytic leukemia
by
Hoferkova, Eva
,
Panovska, Anna
,
Pospisilova, Sarka
in
1-Phosphatidylinositol 3-kinase
,
Adaptation
,
Adenine - analogs & derivatives
2024
Bruton tyrosine kinase (BTK) inhibitor therapy induces peripheral blood lymphocytosis in chronic lymphocytic leukemia (CLL), which lasts for several months. It remains unclear whether nongenetic adaptation mechanisms exist, allowing CLL cells’ survival during BTK inhibitor–induced lymphocytosis and/or playing a role in therapy resistance. We show that in approximately 70% of CLL cases, ibrutinib treatment in vivo increases Akt activity above pretherapy levels within several weeks, leading to compensatory CLL cell survival and a more prominent lymphocytosis on therapy. Ibrutinib-induced Akt phosphorylation (pAkt S473 ) is caused by the upregulation of Forkhead box protein O1 (FoxO1) transcription factor, which induces expression of Rictor , an assembly protein for the mTORC2 protein complex that directly phosphorylates Akt at serine 473 (S473). Knockout or inhibition of FoxO1 or Rictor led to a dramatic decrease in Akt phosphorylation and growth disadvantage for malignant B cells in the presence of ibrutinib (or PI3K inhibitor idelalisib) in vitro and in vivo. The FoxO1/Rictor/pAkt S473 axis represents an early nongenetic adaptation to B cell receptor (BCR) inhibitor therapy not requiring PI3Kδ or BTK kinase activity. We further demonstrate that FoxO1 can be targeted therapeutically and its inhibition induces CLL cells’ apoptosis alone or in combination with BTK inhibitors (ibrutinib, acalabrutinib, pirtobrutinib) and blocks their proliferation triggered by T cell factors (CD40L, IL-4, and IL-21).
Journal Article
Long-Term Cryopreservation Does Not Affect Quality of Peripheral Blood Stem Cell Grafts: A Comparative Study of Native, Short-Term and Long-Term Cryopreserved Haematopoietic Stem Cells
by
Vlas, Tomáš
,
Holubova, Monika
,
Georgiev, Daniel
in
Aldehyde dehydrogenase
,
Apoptosis
,
Autografts
2021
Cryopreserved haematopoietic progenitor cells are used to restore autologous haematopoiesis after high dose chemotherapy. Although the cells are routinely stored for a long period, concerns remain about the maximum storage time and the possible negative effect of storage on their potency. We evaluated the effect of cryopreservation on the quality of peripheral stem cell grafts stored for a short (3 months) and a long (10 years) period and we compared it to native products.The viability of CD34+ cells remained unaffected during storage, the apoptotic cells were represented up to 10% and did not differ between groups. The clonogenic activity measured by ATP production has decreased with the length of storage (ATP/cell 1.28 nM in native vs. 0.63 in long term stored products, P < 0.05). Only borderline changes without statistical significance were detected when examining mitochondrial and aldehyde dehydrogenase metabolic activity and intracellular pH, showing their good preservation during cell storage. Our experience demonstrates that cryostorage has no major negative effect on stem cell quality and potency, and therefore autologous stem cells can be stored safely for an extended period of at least 10 years. On the other hand, long term storage for 10 years and longer may lead to mild reduction of clonogenic capacity. When a sufficient dose of stem cells is infused, these changes will not have a clinical impact. However, in products stored beyond 10 years, especially when a low number of CD34+ cells is available, the quality of stem cell graft should be verified before infusion using the appropriate potency assays.
Journal Article
Type I interferon signaling in malignant blasts contributes to treatment efficacy in AML patients
2023
While type I interferon (IFN) is best known for its key role against viral infection, accumulating preclinical and clinical data indicate that robust type I IFN production in the tumor microenvironment promotes cancer immunosurveillance and contributes to the efficacy of various antineoplastic agents, notably immunogenic cell death inducers. Here, we report that malignant blasts from patients with acute myeloid leukemia (AML) release type I IFN via a Toll-like receptor 3 (TLR3)-dependent mechanism that is not driven by treatment. While in these patients the ability of type I IFN to stimulate anticancer immune responses was abolished by immunosuppressive mechanisms elicited by malignant blasts, type I IFN turned out to exert direct cytostatic, cytotoxic and chemosensitizing activity in primary AML blasts, leukemic stem cells from AML patients and AML xenograft models. Finally, a genetic signature of type I IFN signaling was found to have independent prognostic value on relapse-free survival and overall survival in a cohort of 132 AML patients. These findings delineate a clinically relevant, therapeutically actionable and prognostically informative mechanism through which type I IFN mediates beneficial effects in patients with AML.
Journal Article
In vivo NMR spectroscopy
by
Lysak, Daniel H.
,
Cahill, Lindsay S.
,
Simpson, Andre J.
in
Best practice
,
Biological activity
,
Bisphenol A
2023
Understanding biological processes at the molecular level is a pillar of modern science, and unique insight can be gained by studying living organisms in real time. As a non-destructive and non-targeted technique, NMR spectroscopy is uniquely capable of characterizing the chemical profile of living organisms during biochemical processes or in response to an applied stressor. In vivo NMR spectroscopy — the study of living organisms by NMR — is discussed here, including the most common and state-of-the-art experimental approaches spanning both solution-state and magic-angle spinning NMR. Key information that can be obtained and important applications — primarily monitoring biochemical processes such as growth and stress responses — are also examined. To date, in vivo NMR has been used in metabolomics studies of microorganisms, plants and invertebrates but it also has potential for medical and pharmaceutical research. Current limitations, best practices for reproducibility and optimizations are also described, including experiments and technologies capable of improving in vivo analysis. This Primer is designed to form a solid foundation for those looking to better understand or incorporate in vivo NMR studies into their own research as well as to shed light on the future of in vivo NMR.In vivo NMR spectroscopy of whole, living multicellular organisms involves maintaining live organisms within an NMR spectrometer and analysing their metabolic profiles in real time. In this Primer, Lysak and colleagues describe experimental approaches for in vivo NMR, including solution-state and magic-angle spinning NMR.
Journal Article
Enhancing reproducibility in single cell research with biocytometry: An inter-laboratory study
by
Ossman, Landon A.
,
Morgan, Angelina M.
,
Foster, Michael J.
in
Antigens
,
Biology and Life Sciences
,
Cells
2024
Biomedicine today is experiencing a shift towards decentralized data collection, which promises enhanced reproducibility and collaboration across diverse laboratory environments. This inter-laboratory study evaluates the performance of biocytometry, a method utilizing engineered bioparticles for enumerating cells based on their surface antigen patterns. In centralized and aggregated inter-lab studies, biocytometry demonstrated significant statistical power in discriminating numbers of target cells at varying concentrations as low as 1 cell per 100,000 background cells. User skill levels varied from expert to beginner capturing a range of proficiencies. Measurement was performed in a decentralized environment without any instrument cross-calibration or advanced user training outside of a basic instruction manual. The results affirm biocytometry to be a viable solution for immunophenotyping applications demanding sensitivity as well as scalability and reproducibility and paves the way for decentralized analysis of rare cells in heterogeneous samples.
Journal Article
Less renal allograft fibrosis with valganciclovir prophylaxis for cytomegalovirus compared to high-dose valacyclovir: a parallel group, open-label, randomized controlled trial
by
Kormunda, Stanislav
,
Hermanova, Hana
,
Lysak, Daniel
in
Adult
,
Antibiotic Prophylaxis - methods
,
Antiviral Agents - therapeutic use
2018
Background
Cytomegalovirus (CMV) prophylaxis may prevent CMV indirect effects in renal transplant recipients. This study aimed to compare the efficacy of valganciclovir and valacyclovir prophylaxis for CMV after renal transplantation with the focus on chronic histologic damage within the graft.
Methods
From November 2007 through April 2012, adult renal transplant recipients were randomized, in an open-label, single-center study, at a 1:1 ratio to 3-month prophylaxis with valganciclovir (
n
= 60) or valacyclovir (
n
= 59). The primary endpoint was moderate-to-severe interstitial fibrosis and tubular atrophy assessed by protocol biopsy at 3 years evaluated by a single pathologist blinded to the study group. The analysis was conducted in an intention-to-treat population.
Results
Among the 101 patients who had a protocol biopsy specimen available, the risk of moderate-to-severe interstitial fibrosis and tubular atrophy was significantly lower in those treated with valganciclovir (22% versus 34%; adjusted odds ratio, 0.31; 95% confidence interval, 0.11–0.90;
P
= 0.032 by multivariate logistic regression). The incidence of CMV disease (9% versus 2%;
P
= 0.115) and CMV DNAemia (36% versus 42%;
P
= 0.361) were not different at 3 years.
Conclusions
Valganciclovir prophylaxis, as compared with valacyclovir, was associated with a reduced risk of moderate-to-severe interstitial fibrosis and tubular atrophy in patients after renal transplantation.
Trial registration
Australian New Zealand Clinical Trials Registry (
ACTRN12610000016033
). Registered on September 26, 2007
Journal Article
Dynamic Changes of Inhibitory Killer-Immunoglobulin-Like Receptors on NK Cells after Allogeneic Hematopoietic Stem Cell Transplantation: An Initial Study
2020
Killer-immunoglobulin-like receptors (KIRs) are critical natural killer (NK) cell regulators. The expression of KIRs is a dynamic process influenced by many factors. Their ligands—HLA(Human Leukocyte Antigen) class I molecules—are expressed on all nucleated cells that keep NK cells under control. In hematopoietic stem cell transplantation (HSCT), NK cells play an essential role in relapse protection. In the presented pilot study, we characterized the dynamic expression of inhibitory KIRS (iKIRs), which protect cells against untoward lysis, in donors and patients during the first three months after HSCT using flow cytometry. The expression of all iKIRs was highly variable and sometimes correlated with patients’ clinical presentation and therapy regiment. Cyclophosphamide (Cy) in the graft-versus-host disease (GvHD) prevention protocol downregulated KIR2DL1 to just 25% of the original donor value, and the FEAM (Fludarabine + Etoposid + Ara-C + Melphalan) conditioning protocol reduced KIR2DL3. In lymphoid neoplasms, there was a slightly increased KIR2DL3 expression compared to myeloid malignancies. Additionally, we showed that the ex vivo activation of NK cells did not alter the level of iKIRs. Our study shows the influence of pre- and post-transplantation protocols on iKIR expression on the surface of NK cells and the importance of monitoring their cell surface.
Journal Article