The objective of this study was to provide a systematic review and meta-analysis to quantify prognosis and identify factors associated with variations in reported mortality estimates among infants ...who were born at 22 weeks of gestation and provided proactive treatment (resuscitation and intensive care).
PubMed, Scopus, and Web of Science databases, with no language restrictions, were searched for articles published from January 2000 to February 2020.
Reports on live-born infants who were delivered at 22 weeks of gestation and provided proactive care were included. The primary outcome was survival to hospital discharge; secondary outcomes included survival without major morbidity and survival without neurodevelopmental impairment. Because we expected differences across studies in the definitions for various morbidities, multiple definitions for composite outcomes of major morbidities were prespecified. Neurodevelopmental impairment was based on Bayley Scales of Infant Development II or III. Data extractions were performed independently, and outcomes agreed on a priori.
Methodological quality was assessed using the Quality in Prognostic Studies tool. An adapted version of the Grading of Recommendations Assessment, Development and Evaluation approach for prognostic studies was used to evaluate confidence in overall estimates. Outcomes were assessed as prevalence and 95% confidence intervals. Variabilities across studies attributable to heterogeneity were estimated with the I2 statistic; publication bias was assessed with the Luis Furuya-Kanamori index. Data were pooled using the inverse variance heterogeneity model.
Literature searches returned 21,952 articles, with 2034 considered in full; 31 studies of 2226 infants who were delivered at 22 weeks of gestation and provided proactive neonatal treatment were included. No articles were excluded for study design or risk of bias. The pooled prevalence of survival was 29.0% (95% confidence interval, 17.2–41.6; 31 studies, 2226 infants; I2=79.4%; Luis Furuya-Kanamori index=0.04). Survival among infants born to mothers receiving antenatal corticosteroids was twice the survival of infants born to mothers not receiving antenatal corticosteroids (39.0% vs 19.5%; P<.01). The overall prevalence of survival without major morbidity, using a definition that includes any bronchopulmonary dysplasia, was 11.0% (95% confidence interval, 8.0–14.3; 10 studies, 374 infants; I2=0%; Luis Furuya-Kanamori index=3.02). The overall rate of survival without moderate or severe impairment was 37.0% (95% confidence interval, 14.6–61.5; 5 studies, 39 infants; I2=45%; Luis Furuya-Kanamori index=−0.15). Based on the year of publication, survival rates increased between 2000 and 2020 (slope of the regression line=0.09; standard error=0.03; P<.01). Studies were highly diverse with regard to interventions and outcomes reported.
The reported survival rates varied greatly among studies and were likely influenced by combining observational data from disparate sources, lack of individual patient–level data, and bias in the component studies from which the data were drawn. Therefore, pooled results should be interpreted with caution. To answer fundamental questions beyond the breadth of available data, multicenter, multidisciplinary collaborations, including alignment of important outcomes by stakeholders, are needed.
BCL-XL, an anti-apoptotic BCL-2 family protein, plays a key role in cancer cell survival. However, the potential of BCL-XL as an anti-cancer target has been hampered by the on-target platelet ...toxicity because platelets depend on BCL-XL to maintain their viability. Here we report the development of a PROTAC BCL-XL degrader, XZ424, which has increased selectivity for BCL-XL-dependent MOLT-4 cells over human platelets compared with conventional BCL-XL inhibitors. This proof-of-concept study demonstrates the potential of utilizing a PROTAC approach to achieve tissue selectivity.
The Cellular Therapeutics Laboratory at the Brown Cancer Center, UofL Health has optimized its protocols to cover the entire process of collection, freezing, storage, thawing and testing to achieve ...high post-thaw viability of Hematopoietic Stem Cell (HSC) products.
The number and viability of CD34+ HSC in cryopreserved products plays a key role in the success or otherwise of stem cell transplant. There is a wide variation in the way different cell therapy laboratories perform cryopreservation, thawing, and testing. Arguably, this leads to a wide variation in the acceptability cutoff of the proportion of viable cells in post-thaw specimens.
14 specimens from the laboratory's HSC specimens were used in this study. Time in storage ranged from 1 - 16 yrs, with an average of 7.5 yrs. Harvested nucleated cells are suspended in a freeze media of equal volumes of Origin CryoPur 100% DMSO and Plasma-Lyte A with a final concentration of 10% DMSO and cryopreserved at a controlled rate. The control rate freezing allows for the optimal viability of post-thaw cellular products. To maintain the maximum nucleated cell viability, cells are rapidly thawed in a 40°C ± 2°C water bath.
A 3-step method for post-thaw analysis is used for preparing the sample for testing. Thaw media is prepared using 20 ml of 25% Human Serum Albumin solution + 80 ml of Plasma-Lyte A. At room temp, the thawed sample is diluted 1:2 by three additions of 1/3 sample volume with thaw media separated by 5-minute intervals.
A critical component of the optimization process is testing. Rapid transport of the aliquot to be tested and immediate dilution, staining, and acquisition are all instrumental in the process. Single-platform flow cytometry is performed using CD34 PE, CD45 FITC, and 7-AAD in accordance with ISHAGE guidelines. Incubation with the reagents does not exceed 20 minutes (room temp, in the dark) and no lysis buffer is added at the end. Only a 2% serum-supplemented isotonic buffer is used, followed promptly by acquisition on the cytometer. The average viability of CD34+CD45dimSSClowFSClow cells achieved following this protocol is 98%; the average viability of CD45+ total nucleated cells is 69.5%.
Optimized freezing, storage, thawing, processing, and analysis protocols help achieve CD34 counts with high viability, accurately representative of the CD34 content of HSC products. We hope this will help standardize the acceptability criteria labs set for post-thaw viability.
The MTT assay for cellular metabolic activity is almost ubiquitous to studies of cell toxicity; however, it is commonly applied and interpreted erroneously. We investigated the applicability and ...limitations of the MTT assay in representing treatment toxicity, cell viability, and metabolic activity. We evaluated the effect of potential confounding variables on the MTT assay measurements on a prostate cancer cell line (PC-3) including cell seeding number, MTT concentration, MTT incubation time, serum starvation, cell culture media composition, released intracellular contents (cell lysate and secretome), and extrusion of formazan to the extracellular space. We also assessed the confounding effect of polyethylene glycol (PEG)-coated gold nanoparticles (Au-NPs) as a tested treatment in PC-3 cells on the assay measurements. We additionally evaluated the applicability of microscopic image cytometry as a tool for measuring intracellular MTT reduction at the single-cell level. Our findings show that the assay measurements are a result of a complicated process dependant on many of the above-mentioned factors, and therefore, optimization of the assay and rational interpretation of the data is necessary to prevent misleading conclusions on variables such as cell viability, treatment toxicity, and/or cell metabolism. We conclude, with recommendations on how to apply the assay and a perspective on where the utility of the assay is a powerful tool, but likewise where it has limitations.
The ideal scenario in most applications of microbial diagnostics is that only viable cells are detected. Bacteria were traditionally considered viable when they could be cultured, whereas today's ...viability concept tends to be alternatively based on the presence of some form of metabolic activity, a positive energy status, responsiveness, detection of RNA transcripts that tend to degrade rapidly after cell death, or of an intact membrane. The latter criterion, although conservative, was the focus of one of the most successful recent approaches to detect viable cells in combination with DNA amplification techniques. The technology is based on sample treatment with the photoactivatable, and cell membrane impermeant, nucleic acid intercalating dyes ethidium monoazide (EMA) or propidium monoazide (PMA) followed by light exposure prior to extraction of DNA and amplification. Light activation of DNA-bound dye molecules results in irreversible DNA modification and subsequent inhibition of its amplification. Sample pretreatment with viability dyes has so far been mainly used in combination with PCR (leading to the term viability PCR, v-PCR), and increasingly with isothermal amplification method. The principle is not limited to bacteria, but has also successfully been applied to fungi, protozoa and viruses. Despite the success of the method, some practical limitations have been identified, especially when applied to environmental samples. In part they can be minimized by choice of experimental parameters and conditions adequate for a particular sample. This review summarizes current knowledge and presents aspects which are important when designing experiments employing viability dyes.
► This review summarizes current knowledge of the viable PCR technique. ► Viable PCR is a promising technique; but in some cases practical limitations have been found. ► Viable PCR efficiency depends on a complex set of parameters that are summarizes and discussed in this review. ► General recommendations that might be useful for assay optimization are fully discussed throughout the review.
Cell Viability Under Anoxic Conditions WAGNER, Stephanie; POHL, Jakob; HACKBARTH, Steffen
Photodiagnosis and photodynamic therapy,
March 2023, 2023-03-00, Letnik:
41
Journal Article
Recenzirano
PDT relies on the availability of oxygen to generate cytotoxic ROS and singlet oxygen in particular. Yet, after photosensitizer illumination, the oxygen in the direct vicinity is consumed very ...quickly through reactions with biological material, especially in the hypoxic environment caused by the increased metabolism of tumour cells. 1 Considering these facts, the illumination regimes currently used in clinical PDT should be investigated for the extent to which they promote or even hinder generation of singlet oxygen in tumour tissue. Assuming the latter, the question arises of whether illumination induced anoxia might lead to reliable cell death. For this purpose, the correlation between the oxygen available to the cells and their short-, medium- and long-term survival rates was examined.
Using the adherent cell line FaDu as a tumour model, the atmospheric oxygen concentration inside an incubator is adjusted with a gas composition system developed in the group. To determine both the oxygen concentration actually available to the cells and their consumption 2, a simulation of oxygen diffusion in culture medium 3, 4 was derived. The survival rate of the cells was checked with fluorescence-based vitality assays both during and after exposure to anoxia.
Using oxygen consumption achieved through illumination of a photosensitizer in solution in the presence of extracellular quenchers as a first measurement, the determined results compared well with the numerical simulation.
In the series of experiments, it became clear that even at normal atmospheric pressure, significantly less oxygen than expected is available, especially for adherent cells. Accordingly, every system above anoxia is in a highly dynamic state in which the oxygen concentration at the level of the cells differs significantly from the oxygen concentration above the medium. For this reason, the simulation of this complex system, which considers cell respiration and growth as well as oxygen diffusion through the culture medium, was compared with first results of the viability assays.
Although the current experiments included only two cell lines, the model provides deep insights into the role of anoxia in PDT. Furthermore, the model can be easily adapted to the particular metabolisms of different tumours. Thus, it is an important tool to inform future case-based decisions about the potential targeted use of localized anoxia as an alternative therapy.
•Physical NW-EP and chemical Cl2 were compared to remove culturable and viable cells.•NW-EP had ∼3–5 times lower energy consumption for culturable cell removal than Cl2.•NW-EP inhibited the formation ...of VBNC cells via destroying cell wall and membrane.•Osmotic pressure caused gradual inactivation of VBNC cells with cell wall damage.•NW-EP showed excellent adaptability to control VBNC cells in DI, tap and lake waters.
The induction of viable but nonculturable (VBNC) bacteria with cellular integrity and low metabolic activity by chemical disinfection causes a significant underestimation of potential microbiological risks in drinking water. Herein, a physical Co3O4 nanowire-assisted electroporation (NW-EP) was developed to induce cell damage via the locally enhanced electric field over nanowire tips, potentially achieving effective inhibition of VBNC cells as compared with chemical chlorination (Cl2). NW-EP enabled over 5-log removal of culturable cell for various G+/G- bacteria under voltage of 1.0 V and hydraulic retention time of 180 s, and with ∼3–6 times lower energy consumption than Cl2. NW-EP also achieved much higher removals (∼84.6 % and 89.5 %) of viable Bacillus cereus (G+) and Acinetobacter schindleri (G-) via generating unrecoverable pores on cell wall and reversible/irreversible pores on cell membrane than Cl2 (∼28.6 % and 41.1 %) with insignificant cell damage. The residual VBNC bacteria with cell wall damage and membrane pore resealing exhibited gradual inactivation by osmotic stress, leading to ∼99.8 % cell inactivation after 24 h storage (∼59.4 % for Cl2). Characterizations of cell membrane integrity and cell morphology revealed that osmotic stress promoted cell membrane damage for the gradual inactivation of VBNC cells during storage. The excellent adaptability of NW-EP for controlling VBNC cells in DI, tap and lake waters suggested its promising application potentials for drinking water, such as design of an external device on household taps.
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Abstract
Funding Acknowledgements
Type of funding sources: None.
Introduction
Department for nuclear medicine in the University medical centre Ljubljana provides nuclear medicine diagnostic ...procedures for approximately 1.000.000 inhabitants of Slovenia. As many countries in Europe, Slovenia was faced with the first wave of the COVID-19 pandemic in early spring of 2020. Since our country is situated next to the northern part of Italy, where the situation was critical, our Ministry of health issued specific recommendations in March 2020. The aim was to increase hospital capacities for COVID-19 patients through limiting non-urgent diagnostic tests including myocardial perfusion scintigraphy (MPS) and to minimize the spread of the virus into hospital departments. The epidemiologic situation of the first wave resolved within 3 months. In the second wave of the pandemic in autumn 2020, the recommendations on patient care in non COVID-19 cases were less limiting to avoid worsening of non COVID-19 related diseases and patient prognosis.
Purpose
The aim of our study was to evaluate the influence of the COVID-19 pandemic on MPS in our medical institution.
Methods
Data on numbers of MPS, clinical characteristics of the patients and findings of MPS were prospectively collected for the first wave (in spring from March 15th to June 15th 2020) and second wave (in autumn from September 15th to December 15th 2020) of the pandemic and were compared with the same periods in 2019.
Results
During the first wave we performed 40% less MPS, significantly more patients had pharmacological stress and were outpatients than in spring 2019. There were no significant differences in other clinical characteristics and MPS findings (Table 1 and Figure 1). In autumn 2020 we reorganized our schedule to increase the number of patients, which was once again comparable to previous year’s autumn. Although the number of patients was comparable, patients were now significantly older and had more often pharmacological stress, but there were no significant differences in other clinical data or MPS findings (Table 1 and Figure 1).
Conclusions
In our hospital, during the first wave of COVID-19 pandemic, we performed significantly less MPS than in the same period of the previous year. To minimize the possibility of virus transmission from asymptomatic patients, we followed international recommendations and avoided exercise stress tests but increased the percentage of pharmacological stress tests. A similar approach regarding the type of stress tests was chosen for the second wave in autumn of 2020. However, we decided to increase the number of MPS performed, in order to lessen the negative impact of the pandemic on non COVID-19 related diseases, focusing on coronary artery disease.
Field pea (Pisum sativum), a major grain legume crop, is autogamous and adapted to temperate climates. The objectives of this study were to investigate effects of high temperature stress on stamen ...chemical composition, anther dehiscence, pollen viability, pollen interactions with pistil and ovules, and ovule growth and viability. Two cultivars (“CDC Golden” and “CDC Sage”) were exposed to 24/18°C (day/night) continually or to 35/18°C for 4 or 7 days. Heat stress altered stamen chemical composition, with lipid composition of “CDC Sage” being more stable compared with “CDC Golden.” Heat stress reduced pollen viability and the proportion of ovules that received a pollen tube. After 4 days at 35°C, pollen viability in flower buds decreased in “CDC Golden,” but not in “CDC Sage.” After 7 days, partial to full failure of anthers to dehisce resulted in subnormal pollen loads on stigmas. Although growth (ovule size) of fertilized ovules was stimulated by 35°C, heat stress tended to decrease ovule viability. Pollen appears susceptible to stress, but not many grains are needed for successful fertilization. Ovule fertilization and embryos are less susceptible to heat, but further research is warranted to link the exact degree of resilience to stress intensity.
Heat stress induced anther indehiscence and reduced pollen viability and the proportion of ovules that received a pollen tube in field pea. Heat stress also altered stamen chemical composition, with the lipid composition of “CDC Sage” being more stable than “CDC Golden,” which may explain the greater robustness of pollen viability in “CDC Sage” to heat. Ovule viability is less susceptible to heat stress.
How do members' and leaders' social network structures help or hinder team effectiveness? A meta-analysis of 37 studies of teams in natural contexts suggests that teams with densely configured ...interpersonal ties attain their goals better and are more committed to staying together; that is, team task performance and viability are both higher. Further, teams with leaders who are central in the teams' intragroup networks and teams that are central in their intergroup network tend to perform better. Time sequencing, member familiarity, and tie content moderate structure-performance connections. Results suggest stronger incorporation of social network concepts into theories about team effectiveness.
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