Investigation of Developmental Stage/Age, Gamma Irradiation Dose, and Temperature in Sterilization of Male Aedes aegypti (Diptera: Culicidae) in a Sterile Insect Technique Program

The sterilization process using gamma irradiation is a crucial component in a program using sterile insect technique (SIT) to control Aedes aegypti. Unfortunately, there is no efficient standard protocol for sterilizing mosquitoes that can produce a high level of sterility while maintaining mating ability and longevity. Therefore, we conducted a study of the critical factors necessary to develop such a standard protocol. In this study, male Ae. aegypti pupae, as well as adults aged 1 d and 3 d, were irradiated using a Gamma-cell 220 irradiator doses of 0, 20, 40, 60, 70, 80, and 100 Gray (Gy). In addition, male Ae. aegypti in the pupal and adult stage aged 1 d were irradiated at a dose of 70 Gy at various temperatures. Changes in emergence rates, longevity, sterility, and mating competitiveness were recorded for each combination of parameters. Results showed that an increase of irradiation dose leads to a rise of induced sterility at all developmental stages, while simultaneously reducing emergence rate, survival, and mating competitiveness. Higher temperatures resulted in increased levels of sterility, reduced longevity, and did not affect the ability to mate. This study found that an irradiation dose of 70 Gy at a temperature between 20.00 and 22.30°C administered in the pupal stage induced a high level of sterility (around 98%), while maintaining mating competitiveness and longevity.

Nonmicrobial Activation of TLRs Controls Intestinal Growth, Wound Repair, and Radioprotection

TLRs, key components of the innate immune system, recognize microbial molecules. However, TLRs also recognize some nonmicrobial molecules. In particular, TLR2 and TLR4 recognize hyaluronic acid, a glycosaminoglycan in the extracellular matrix. In neonatal mice endogenous hyaluronic acid binding to TLR4 drives normal intestinal growth. Hyaluronic acid binding to TLR4 in pericryptal macrophages results in cyclooxygenase2- dependent PGE2 production, which transactivates EGFR in LGR5+ crypt epithelial stem cells leading to increased proliferation. The expanded population of LGR5+ stem cells leads to crypt fission and lengthening of the intestine and colon. Blocking this pathway at any point (TLR4 activation, PGE2 production, EGFR transactivation) results in diminished intestinal and colonic growth. A similar pathway leads to epithelial proliferation in wound repair. The repair phase of dextran sodium sulfate colitis is marked by increased epithelial proliferation. In this model, TLR2 and TLR4 in pericryptal macrophages are activated by microbial products or by host hyaluronic acid, resulting in production of CXCL12, a chemokine. CXCL12 induces the migration of cyclooxygenase2-expressing mesenchymal stem cells from the lamina propria of the upper colonic crypts to a site adjacent to LGR5+ epithelial stem cells. PGE2 released by these mesenchymal stem cells transactivates EGFR in LGR5+ epithelial stem cells leading to increased proliferation. Several TLR2 and TLR4 agonists, including hyaluronic acid, are radioprotective in the intestine through the inhibition of radiation-induced apoptosis in LGR5+ epithelial stem cells. Administration of exogenous TLR2 or TLR4 agonists activates TLR2/TLR4 on pericryptal macrophages inducing CXCL12 production with migration of cyclooxygenase2-expressing mesenchymal stem cells from the lamina propria of the villi to a site adjacent to LGR5+ epithelial stem cells. PGE2 produced by these mesenchymal stem cells, blocks radiation-induced apoptosis in LGR5+ epithelial stem cells by an EGFR mediated pathway.

Evaluation of perfusion MRI value for tumor progression assessment after glioma radiotherapy: A systematic review and meta-analysis

OBJECTIVES

This study aimed to evaluate the diagnostic performance of magnetic resonance perfusion-weighted imaging (PWI) as a noninvasive method to assess post-treatment radiation effect and tumor progression in patients with glioma.

METHODS

A systematic literature search was performed in the PubMed, Cochrane Library, and Embase databases up to March 2020. The quality of the included studies was assessed by the quality assessment of diagnostic accuracy studies 2. Data were extracted to calculate sensitivity, specificity, and diagnostic odds ratio (DOR), 95% Confidence interval (CI) and analyze the heterogeneity of the studies (Spearman correlation coefficient, I2 test). We performed meta-regression and subgroup analyses to identify the impact of study heterogeneity.

RESULTS

Twenty studies were included, with available data for analysis on 939 patients and 968 lesions. All included studies used dynamic susceptibility contrast (DSC) PWI, four also used dynamic contrast-enhanced PWI, and three also used arterial spin marker imaging PWI. When DSC was considered, the pooled sensitivity and specificity were 0.83 (95% CI, 0.79 to 0.86) and 0.83 (95% CI, 0.78 to 0.87), respectively; pooled DOR, 21.31 (95% CI, 13.07 to 34.73); area under the curve (AUC), 0.887; Q∗, 0.8176. In studies using dynamic contrast-enhanced, the pooled sensitivity and specificity were 0.73 (95% CI, 0.66 to 0.80) and 0.80 (95% CI, 0.69 to 0.88), respectively; pooled DOR, 10.83 (95% CI, 2.01 to 58.43); AUC, 0.9416; Q∗, 0.8795. In studies using arterial spin labeling, the pooled sensitivity and specificity were 0.79 (95% CI, 0.69 to 0.87) and 0.78 (95% CI, 0.67 to 0.87), respectively; pooled DOR, 15.63 (95% CI, 4.61 to 53.02); AUC, 0.8786; Q∗, 0.809.

CONCLUSIONS

Perfusion magnetic resonance imaging displays moderate overall accuracy in identifying post-treatment radiation effect and tumor progression in patients with glioma. Based on the current evidence, DSC-PWI is a relatively reliable option for assessing tumor progression after glioma radiotherapy.

How Precision Medicine Might Better Serve Downwinders

Despite the advances in developing nuclear weapons and other technologies, not much is known about the long-term effects of radiation on human health. In a world where nuclear energy could help curb carbon emissions, it almost seems paradoxical that its possible long-term risks and impacts to human health are still poorly understood. While researchers have investigated the effects of acute radiation in the aftermath of nuclear incidents such as Chernobyl, Hiroshima, Nagasaki, and Fukushima, more needs to be done to understand the impacts of long-term and low-dose nuclear radiation. Studying the downwinders from the Nevada Test Site could offer one window to investigate those myriad effects.

Economic burden of skeletal-related events in patients with multiple myeloma: analysis of US commercial claims database

AIMS

To estimate incremental healthcare resource utilization (HRU) and costs associated with skeletal-related events (SREs) secondary to multiple myeloma (MM), and HRU and cost differences in patients with one vs multiple SREs.

METHODS

Adults with MM diagnosis between January 1, 2010-December 31, 2014, with benefits coverage ≥12 months pre- and ≥6 months post-diagnosis were followed to last coverage date or December 31, 2015, excluding patients with prior anti-myeloma treatment or cancers. SREs were identified by diagnosis or procedure codes (pathological fracture, spinal cord compression, radiation, or surgery to the bone). SRE patients (index = first post-diagnosis SRE) were propensity score matched 1:1 to patients without SRE (assigned pseudo-index) using baseline characteristics, and ≥1 month of continuous enrollment after index/pseudo-index date was required. Per-patient-per year (PPPY) HRU and costs (2016 US$) were determined for inpatient, outpatient, emergency department (ED), and outpatient pharmacy services during follow-up. Wilcoxon signed rank for means and McNemar's tests for proportions were used to assess differences. Negative binomial regression and generalized linear regression analyses estimated differences in HRU and costs, respectively, for the comparison of single vs multiple SREs.

RESULTS

Each cohort included 848 patients (mean age = 61 - 62 years, 57% male) with no significant differences in pre-index demographic or clinical characteristics between matched cohorts. Versus non-SRE patients, SRE patients had significantly higher PPPY use (p < .0001) of inpatient hospitalizations, ED visits, outpatient pharmacy, and higher direct medical costs ($188,723 vs $108,160, p < .0001). Adjusted PPPY total costs were $209,820 in patients with multiple SREs; $159,797 in patients with one SRE.

LIMITATIONS

SRE misclassification and residual confounding are possible.

CONCLUSIONS

Among patients with MM, average annual costs were substantially higher in patients with SRE compared with matched non-SRE patients. The economic burden of SRE increased further with multiple events.

Some Observations on the Epidemiology and the Pathology of Reticulum Cell Sarcomas in (C57BL/Cne x C3H/Cne) F1 Mice

Life-long observations on untreated animals have shown that spontaneous reticulum cell sarcomas (RCS) developed in 56.5 % male mice of the hybrid (C57BL/Cne x C3H/Cne) F1 strain; the average age at death of mice with tumors was 949 days, compared with 929 days for all causes: no age-specific peak of mortality has been shown to occur over the entire life span of the animals. Histologically, the spleen and all the lymphnodes, including the mesenteric node, were always invaded; neoplastic growth was found less frequently in kidneys, liver and lungs (77, 70, and 40%, respectively), only occasionally in other organs such as adrenals and testes, and never in the thymus. The tumor was predominantly composed of a single type of neoplastic cells, resembling highly undifferentiated reticular cells, typically proliferating from the periarteriolar region of the lymphatic follicles in the spleen. The monomorphic aspect of the tumor cell population suggests that RCS in this strain of mice may be classified as type A according to Dunn. Electron-microscopy observations showed the presence of a few virus-like particles both in tumor cells and in sediments from cell-free extracts. Transplantation of cells from spontaneous RCS into both normal and lethally-irradiated syngeneic recipients was successful only in 4 out of 7 experiments, regardless of the tissue of origin of the neoplastic cells (spleen, lymphnodes or bone marrow). Virus-like particles were seen with higher frequency in transplanted tumors. Inoculation of cell-free extracts into neonatal mice of low-leukemia strains has not so far been successful. Splenectomy of young animals as well as the intravenous injection of syngeneic bone marrow cells immediately following a lethal dose of whole-body X-irradiation significantly reduced the frequency of spontaneous tumors.

The Habitability of Proxima Centauri b: Environmental States and Observational Discriminants

Proxima Centauri b provides an unprecedented opportunity to understand the evolution and nature of terrestrial planets orbiting M dwarfs. Although Proxima Cen b orbits within its star's habitable zone, multiple plausible evolutionary paths could have generated different environments that may or may not be habitable. Here, we use 1-D coupled climate-photochemical models to generate self-consistent atmospheres for several evolutionary scenarios, including high-O2, high-CO2, and more Earth-like atmospheres, with both oxic and anoxic compositions. We show that these modeled environments can be habitable or uninhabitable at Proxima Cen b's position in the habitable zone. We use radiative transfer models to generate synthetic spectra and thermal phase curves for these simulated environments, and use instrument models to explore our ability to discriminate between possible planetary states. These results are applicable not only to Proxima Cen b but to other terrestrial planets orbiting M dwarfs. Thermal phase curves may provide the first constraint on the existence of an atmosphere. We find that James Webb Space Telescope (JWST) observations longward of 10 μm could characterize atmospheric heat transport and molecular composition. Detection of ocean glint is unlikely with JWST but may be within the reach of larger-aperture telescopes. Direct imaging spectra may detect O4 absorption, which is diagnostic of massive water loss and O2 retention, rather than a photosynthetic biosphere. Similarly, strong CO2 and CO bands at wavelengths shortward of 2.5 μm would indicate a CO2-dominated atmosphere. If the planet is habitable and volatile-rich, direct imaging will be the best means of detecting habitability. Earth-like planets with microbial biospheres may be identified by the presence of CH4-which has a longer atmospheric lifetime under Proxima Centauri's incident UV-and either photosynthetically produced O2 or a hydrocarbon haze layer. Key Words: Planetary habitability and biosignatures-Planetary atmospheres-Exoplanets-Spectroscopic biosignatures-Planetary science-Proxima Centauri b. Astrobiology 18, 133-189.

Unindicated multiphase CT scans in non-traumatic abdominal emergencies for women of reproductive age: a significant source of unnecessary exposure

PURPOSE

To determine the frequency of unindicated CT phases and the resultant excess of absorbed radiation doses to the uterus and ovaries in women of reproductive age who have undergone CT for non-traumatic abdomino-pelvic emergencies.

MATERIALS AND METHODS

We reviewed all abdomino-pelvic CT examinations in women of reproductive age (40 years or less), between 1 June 2012 and 31 January 2015. We evaluated the appropriateness of each CT phase on the basis of clinical indications, according to ACR appropriateness criteria and evidence-based data from the literature. The doses to uterus and ovaries for each phase were calculated with the CTEXPO software, taking into consideration the size-specific dose estimate (SSDE) after measuring the size of every single patient.

RESULTS

The final cohort was composed of 76 female patients with an average age of 30 (from 19 to 40 years). In total, 197 CT phases were performed with an average of 2.6 phases per patient. Out of these, 93 (47%) were unindicated with an average of 1.2 inappropriate phases per patient. Unindicated scans were most frequent for appendicitis and unlocalized abdominal pain. The excesses of mean radiation doses to the uterus and ovaries due to unindicated phases were, respectively, of 38 and 33 mSv per patient.

CONCLUSION

In our experience, unindicated additional CT phases were numerous with a significant excess radiation dose without an associated clinical benefit. This excess of radiation could have been avoided by widespread adoption of the ACR appropriateness criteria and evidence-based data from the literature.

Consequences of the radiation accident at the Mayak production association in 1957 (the 'Kyshtym Accident')

This paper presents an overview of the nuclear accident that occurred at the Mayak Production Association (PA) in the Russian Federation on 29 September 1957, often referred to as 'Kyshtym Accident', when 20 MCi (740 PBq) of radionuclides were released by a chemical explosion in a radioactive waste storage tank. 2 MCi (74 PBq) spread beyond the Mayak PA site to form the East Urals Radioactive Trace (EURT). The paper describes the accident and gives brief characteristics of the efficacy of the implemented protective measures that made it possible to considerably reduce doses to the exposed population. The paper also provides retrospective dosimetry estimates for the members of the EURT Cohort (EURTC) which comprises approximately 21 400 people. During the first two years after the accident a decrease in the group average leukocyte (mainly due to neutrophils and lymphocytes) and thrombocyte count was observed in the population. At later dates an increased excess relative risk of solid cancer incidence and mortality was found in the EURTC.

Bandwidth Limitations of TEM Cells due to Resonances

The first eight to ten TEmnp resonances have been identified in one large (6.1 X 7.3 X 13.0 m) and one small (1.0 X 0.6 X 2.0 m) TEM cell. The resonant frequencies fit a new equivalent coaxial box model with the effective length of the box depending on the mode. Weakly propagating TEmn modes were also detected at frequencies above their respective first-resonance frequencies. A biological body or metal box at the center of the test zone interacts strongly with the TE10p and TE11p resonances, but not with the TE01p resonances. These interactions cause bandwidth limitations in the use of TEM cells for bioeffects dosimetry studies, EMC testing, and probe calibration work.

Patient knowledge and perception of computed tomography scan in the management of chronic rhinosinusitis symptoms

OBJECTIVES/HYPOTHESIS

The objective of this study was to report patients' knowledge and comfort level with computed tomography (CT) imaging for sinus disease and evaluate patient willingness to undergo empiric medical therapy (EMT) versus CT-directed therapy (CTDT).

STUDY DESIGN

Prospective survey study.

METHODS

A 22-item survey was administered to patients with nasal/sinus symptoms in a tertiary care rhinology clinic. Questions elicited patient demographics, imaging history, and knowledge/comfort regarding imaging-related radiation exposure. Patients were presented with the theoretical choice of EMT versus CTDT, given the expected positive predictive value, in chronic rhinosinusitis (CRS) management.

RESULTS

Two hundred patients (52% female, age range 18-83 years) participated. Of these, 85% had symptoms for over 3 months. Only 91 patients (45.5%) were aware that CT imaging involved radiation exposure. Prior CT experience and past sinus surgery (P < .05), but not sex or education level, were associated with increased comfort with CT imaging. Most patients (78%) preferred CTDT over EMT. If a CT sinus was recommended, 77 patients (38.5%) had concerns, of which 26% identified radiation exposure as the leading concern. The majority (70%) were unsure about the relative radiation dose of a conventional CT.

CONCLUSIONS

Patients with CRS symptoms prefer CTDT over EMT if a diagnosis cannot be established definitively using exam findings. Although most patients deferred to the physician regarding the decision to utilize CT imaging, there is low awareness of CT-related radiation exposure, and a significant minority of patients have radiation-related concerns with regard to medical imaging for nasal and sinus symptoms.