Assessment of the risks posed by severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) on surfaces requires data on survival of this virus on environmental surfaces and on how survival is ...affected by environmental variables, such as air temperature (AT) and relative humidity (RH). The use of surrogate viruses has the potential to overcome the challenges of working with SARS-CoV and to increase the available data on coronavirus survival on surfaces. Two potential surrogates were evaluated in this study; transmissible gastroenteritis virus (TGEV) and mouse hepatitis virus (MHV) were used to determine effects of AT and RH on the survival of coronaviruses on stainless steel. At 4°C, infectious virus persisted for as long as 28 days, and the lowest level of inactivation occurred at 20% RH. Inactivation was more rapid at 20°C than at 4°C at all humidity levels; the viruses persisted for 5 to 28 days, and the slowest inactivation occurred at low RH. Both viruses were inactivated more rapidly at 40°C than at 20°C. The relationship between inactivation and RH was not monotonic, and there was greater survival or a greater protective effect at low RH (20%) and high RH (80%) than at moderate RH (50%). There was also evidence of an interaction between AT and RH. The results show that when high numbers of viruses are deposited, TGEV and MHV may survive for days on surfaces at ATs and RHs typical of indoor environments. TGEV and MHV could serve as conservative surrogates for modeling exposure, the risk of transmission, and control measures for pathogenic enveloped viruses, such as SARS-CoV and influenza virus, on health care surfaces.
Summary Background Pneumonia causes more child deaths than does any other disease. Observational studies have indicated that smoke from household solid fuel is a significant risk factor that affects ...about half the world's children. We investigated whether an intervention to lower indoor wood smoke emissions would reduce pneumonia in children. Methods We undertook a parallel randomised controlled trial in highland Guatemala, in a population using open indoor wood fires for cooking. We randomly assigned 534 households with a pregnant woman or young infant to receive a woodstove with chimney (n=269) or to remain as controls using open woodfires (n=265), by concealed permuted blocks of ten homes. Fieldworkers visited homes every week until children were aged 18 months to record the child's health status. Sick children with cough and fast breathing, or signs of severe illness were referred to study physicians, masked to intervention status, for clinical examination. The primary outcome was physician-diagnosed pneumonia, without use of a chest radiograph. Analysis was by intention to treat (ITT). Infant 48-h carbon monoxide measurements were used for exposure-response analysis after adjustment for covariates. This trial is registered, number ISRCTN29007941. Findings During 29 125 child-weeks of surveillance of 265 intervention and 253 control children, there were 124 physician-diagnosed pneumonia cases in intervention households and 139 in control households (rate ratio RR 0·84, 95% CI 0·63–1·13; p=0·257). After multiple imputation, there were 149 cases in intervention households and 180 in controls (0·78, 0·59–1·06, p=0·095; reduction 22%, 95% CI −6% to 41%). ITT analysis was undertaken for secondary outcomes: all and severe fieldworker-assessed pneumonia; severe (hypoxaemic) physician-diagnosed pneumonia; and radiologically confirmed, RSV-negative, and RSV-positive pneumonia, both total and severe. We recorded significant reductions in the intervention group for three severe outcomes—fieldworker-assessed, physician-diagnosed, and RSV-negative pneumonia—but not for others. We identified no adverse effects from the intervention. The chimney stove reduced exposure by 50% on average (from 2·2 to 1·1 ppm carbon monoxide), but exposure distributions for the two groups overlapped substantially. In exposure-response analysis, a 50% exposure reduction was significantly associated with physician-diagnosed pneumonia (RR 0·82, 0·70–0·98), the greater precision resulting from less exposure misclassification compared with use of stove type alone in ITT analysis. Interpretation In a population heavily exposed to wood smoke from cooking, a reduction in exposure achieved with chimney stoves did not significantly reduce physician-diagnosed pneumonia for children younger than 18 months. The significant reduction of a third in severe pneumonia, however, if confirmed, could have important implications for reduction of child mortality. The significant exposure-response associations contribute to causal inference and suggest that stove or fuel interventions producing lower average exposures than these chimney stoves might be needed to substantially reduce pneumonia in populations heavily exposed to biomass fuel air pollution. Funding US National Institute of Environmental Health Sciences and WHO.
Best vitelliform macular dystrophy (BD), autosomal dominant vitreoretinochoroidopathy (ADVIRC), and the autosomal recessive bestrophinopathy (ARB), together known as the bestrophinopathies, are ...caused by mutations in the bestrophin-1 (
) gene affecting anion transport through the plasma membrane of the retinal pigment epithelium (RPE). To date, while no treatment exists a better understanding of BEST1-related pathogenesis may help to define therapeutic targets. Here, we systematically characterize functional consequences of mutant BEST1 in thirteen RPE patient cell lines differentiated from human induced pluripotent stem cells (hiPSCs). Both BD and ARB hiPSC-RPEs display a strong reduction of BEST1-mediated anion transport function compared to control, while ADVIRC mutations trigger an increased anion permeability suggesting a stabilized open state condition of channel gating. Furthermore, BD and ARB hiPSC-RPEs differ by the degree of mutant protein turnover and by the site of subcellular protein quality control with adverse effects on lysosomal pH only in the BD-related cell lines. The latter finding is consistent with an altered processing of catalytic enzymes in the lysosomes. The present study provides a deeper insight into distinct molecular mechanisms of the three bestrophinopathies facilitating functional categorization of the more than 300 known
mutations that result into the distinct retinal phenotypes.
Background The removal of personal protective equipment (PPE) after patient care may result in transfer of virus to hands and clothing of health care workers (HCWs). The risk of transfer can be ...modeled using harmless viruses to obtain quantitative data. To determine whether double-gloving reduces virus transfer to HCWs’ hands and clothing during removal of contaminated PPE, we conducted a human challenge study using bacteriophages to compare the frequency and quantity of virus transfer to hands and clothes during PPE removal with single-gloving and double-gloving technique. Methods Each experiment had a double-gloving phase and a single-gloving phase. Participants donned PPE (ie, contact isolation gown, N95 respirator, eye protection, latex gloves). The gown, respirator, eye protection, and dominant glove were contaminated with bacteriophage. Participants then removed the PPE, and their hands, face, and scrubs were sampled for virus. Results Transfer of virus to hands during PPE removal was significantly more frequent with single-gloving than with double-gloving. Transfer to scrubs was similar during single-gloving and double-gloving. The amount of virus transfer to hands ranged from 0.15 to 2.5 log10 most probable number. Significantly more virus was transferred to participants’ hands after single-gloving than after double-gloving. Conclusions Our comparison of double-gloving and single-gloving using a simulation system with MS2 and a most-probable number method suggests that double gloving can reduce the risk of viral contamination of HCWs’ hands during PPE removal. If incorporated into practice when full PPE is worn, this practice may reduce the risk of viral contamination of HCWs’ hands during PPE removal. The use of double gloves should be explored in larger controlled studies.
Investigation of SAMD1 ablation in mice Campbell, Bruce; Weber, Lisa M; Engle, Sandra J ...
Scientific reports,
02/2023, Volume:
13, Issue:
1
Journal Article
Peer reviewed
Open access
SAM domain-containing protein 1 (SAMD1) has been implicated in atherosclerosis, as well as in chromatin and transcriptional regulation, suggesting a versatile and complex biological function. ...However, its role at an organismal level is currently unknown. Here, we generated SAMD1
and SAMD1
mice to explore the role of SAMD1 during mouse embryogenesis. Homozygous loss of SAMD1 was embryonic lethal, with no living animals seen after embryonic day 18.5. At embryonic day 14.5, organs were degrading and/or incompletely developed, and no functional blood vessels were observed, suggesting failed blood vessel maturation. Sparse red blood cells were scattered and pooled, primarily near the embryo surface. Some embryos had malformed heads and brains at embryonic day 15.5. In vitro, SAMD1 absence impaired neuronal differentiation processes. Heterozygous SAMD1 knockout mice underwent normal embryogenesis and were born alive. Postnatal genotyping showed a reduced ability of these mice to thrive, possibly due to altered steroidogenesis. In summary, the characterization of SAMD1 knockout mice suggests a critical role of SAMD1 during developmental processes in multiple organs and tissues.
Background In the 2003 severe acute respiratory syndrome outbreak, finding viral nucleic acids on hospital surfaces suggested surfaces could play a role in spread in health care environments. Surface ...disinfection may interrupt transmission, but few data exist on the effectiveness of health care germicides against coronaviruses on surfaces. Methods The efficacy of health care germicides against 2 surrogate coronaviruses, mouse hepatitis virus (MHV) and transmissible gastroenteritis virus (TGEV), was tested using the quantitative carrier method on stainless steel surfaces. Germicides were o-phenylphenol/p-tertiary amylphenol) (a phenolic), 70% ethanol, 1:100 sodium hypochlorite, ortho-phthalaldehyde (OPA), instant hand sanitizer (62% ethanol), and hand sanitizing spray (71% ethanol). Results After 1-minute contact time, for TGEV, there was a log10 reduction factor of 3.2 for 70% ethanol, 2.0 for phenolic, 2.3 for OPA, 0.35 for 1:100 hypochlorite, 4.0 for 62% ethanol, and 3.5 for 71% ethanol. For MHV, log10 reduction factors were 3.9 for 70% ethanol, 1.3 for phenolic, 1.7 for OPA, 0.62 for 1:100 hypochlorite, 2.7 for 62% ethanol, and 2.0 for 71% ethanol. Conclusion Only ethanol reduced infectivity of the 2 coronaviruses by >3-log10 after 1 minute. Germicides must be chosen carefully to ensure they are effective against viruses such as severe acute respiratory syndrome coronavirus.
Inhibition of protein-protein interactions (PPIs) via designed peptides is an effective strategy to perturb their biological functions. The Elongin BC heterodimer (ELOB/C) binds to a BC-box motif and ...is essential for cancer cell growth. Here, we report a peptide that mimics the high-affinity BC-box of the PRC2-associated protein EPOP. This peptide tightly binds to the ELOB/C dimer (kD = 0.46 ± 0.02 nM) and blocks the association of ELOB/C with its interaction partners, both in vitro and in the cellular environment. Cancer cells treated with our peptide inhibitor showed decreased cell viability, increased apoptosis, and perturbed gene expression. Therefore, our work proposes that blocking the BC-box-binding pocket of ELOB/C is a feasible strategy to impair its function and inhibit cancer cell growth. Our peptide inhibitor promises novel mechanistic insights into the biological function of the ELOB/C dimer and offers a starting point for therapeutics linked to ELOB/C dysfunction.
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•The heterodimer-forming proteins ELOB and ELOC are essential for cancer cell growth•Peptides mimicking the BC-box of EPOP bind to ELOB/C with high affinity•The peptide blocks ELOB/C-interactions in vitro and in living cells•Peptide-treated cells show impaired growth, perturbed gene expression, and apoptosis
Fischer and Trinh et al. developed a peptide inhibitor that disrupts the binding of the Elongin BC heterodimer (ELOB/C) to its interaction partners. Cancer cells treated with this peptide inhibitor showed decreased cell viability, increased apoptosis, and perturbed gene expression.
Monitoring cerebral blood flow (CBF) during neurosurgery can provide important physiological information for a variety of surgical procedures. CBF measurements are important for assessing whether ...blood flow has returned to presurgical baseline levels and for assessing postsurgical tissue viability. Existing techniques for intraoperative monitoring of CBF based on magnetic resonance imaging are expensive and often impractical, while techniques such as indocyanine green angiography cannot produce quantitative measures of blood flow. Laser speckle contrast imaging (LSCI) is an optical technique that has been widely used to quantitatively image relative CBF in animal models in vivo. In a pilot clinical study, we adapted an existing neurosurgical operating microscope to obtain LSCI images in humans in real time during neurosurgery under baseline conditions and after bipolar cautery. Simultaneously recorded ECG waveforms from the patient were used to develop a filter that helped reduce measurement variabilities due to motion artifacts. Results from this study demonstrate the feasibility of using LSCI to obtain blood flow images during neurosurgeries and its capability to produce full field CBF image maps with excellent spatial resolution in real-time with minimal disruption to the surgical procedure.
Although treatment options of acute myeloid leukemia (AML) have improved over the recent years, prognosis remains poor. Better understanding of the molecular mechanisms influencing and predicting ...treatment efficacy may improve disease control and outcome. Here we studied the expression, prognostic relevance and functional role of the tumor necrosis factor receptor (TNFR) family member Receptor Activator of Nuclear Factor (NF)-κB (RANK) in AML. We conducted an experimental ex vivo study using leukemic cells of 54 AML patients. Substantial surface expression of RANK was detected on primary AML cells in 35% of the analyzed patients. We further found that RANK signaling induced the release of cytokines acting as growth and survival factors for the leukemic cells and mediated resistance of AML cells to treatment with doxorubicin and cytarabine, the most commonly used cytostatic compounds in AML treatment. In line, RANK expression correlated with a dismal disease course as revealed by reduced overall survival. Together, our results show that RANK plays a yet unrecognized role in AML pathophysiology and resistance to treatment, and identify RANK as “functional” prognostic marker in AML. Therapeutic modulation of RANK holds promise to improve treatment response in AML patients.
Adeno-associated virus (AAV) delivery of potent and broadly neutralizing antibodies (bNAbs is a promising approach for the prevention of HIV-1 infection. The immunoglobulin G (IgG)1 subtype is ...usually selected for this application, because it efficiently mediates antibody effector functions and has a somewhat longer half-life. However, the use of IgG1-Fc has been associated with the generation of anti-drug antibodies (ADAs) that correlate with loss of antibody expression. In contrast, we have shown that expression of the antibody-like molecule eCD4-Ig bearing a rhesus IgG2-Fc domain showed reduced immunogenicity and completely protected rhesus macaques from simian-HIV (SHIV)-AD8 challenges. To directly compare the performance of the IgG1-Fc and the IgG2-Fc domains in a prophylactic setting, we compared AAV1 expression of rhesus IgG1 and IgG2 forms of four anti-HIV bNAbs: 3BNC117, NIH45-46, 10-1074, and PGT121. Interestingly, IgG2-isotyped bNAbs elicited significantly lower ADA than their IgG1 counterparts. We also observed significant protection from two SHIV-AD8 challenges in macaques expressing IgG2-isotyped bNAbs, but not from those expressing IgG1. Our data suggest that monoclonal antibodies isotyped with IgG2-Fc domains are less immunogenic than their IgG1 counterparts, and they highlight ADAs as a key barrier to the use of AAV1-expressed bNAbs.
Vectored delivery of broadly neutralizing antibodies (bNAbs) could afford vaccine-like protection from HIV-1. Gardner et al. show that IgG2 forms of bNAbs raised fewer anti-bNAbs in rhesus macaques than did IgG1 forms. Further, protection from SHIV-AD8 decreased with higher levels of anti-bNAbs and lower bNAb concentrations.
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