Dielectric Spectroscopy: Revealing the True Colors of Biological Matter

Accurate characterization of biological matter, for example, in tissue, cells, and biological fluids, is of high importance. For example, early and correct detection of abnormalities, such as cancer, is essential as it enables early and effective type-specific treatment, which is crucial for mortality reduction [1]. Moreover, it is imperative to investigate the effectiveness and toxicity of pharmaceutical treatments before administration in clinical practice [2]. However, biological matter characterization still faces many challenges. State-of-the-art imaging and characterization methods have drawbacks, such as the requirement to attach difficult-to-find and costly labels to the biological target (e.g., COVID-19 rapid tests), expensive equipment (e.g., magnetic resonance imaging), low accuracy (e.g., ultrasound), use of ionizing radiation (e.g., X-rays), and invasiveness [3]. The characterization of biological matter using microwave (μW), millimeter-wave (mmW), and terahertz (THz) spectroscopy is a promising alternative: it is label-free, does not require ionizing radiation, and can be noninvasive. Moreover, there is a significant difference in how different biological materials absorb, reflect, and transmit electromagnetic (EM) waves [4] that is due to the difference in their dielectric properties. The dielectric properties are described by the frequency-dependent material parameter called the complex permittivity f, which expresses how the material responds to an external oscillating electric field. The complex permittivity of a material determines how the material absorbs, reflects, and transmits EM waves at different frequencies (Figure 1). Since each biological material's permittivity spectrum is different, it acts as an EM fingerprint. A material's complex permittivity can be calculated from the reflection and transmission of EM waves through the material, described by the S-parameters, which can be measured using a vector network analyzer (VNA) transmitting and receiving EM waves over a range of frequencies. The amplitude and phase of the transmitted and reflected EM waves at different frequencies are influenced by different underlying biological effects at different scales. That causes the entire spectrum to provide information from the supracellular to the molecular and even atomic scale. © 2000-2012 IEEE.

Analysis of the first 106 telemedicine consultations in a vascular surgery service

Background: Telemedicine became a relevant means to provide healthcare without face-to-face medical evaluation during the COVID-19 pandemic. Aim(s): To describe the effectiveness of telemedicine in vascular surgery. Material(s) and Method(s): Review of medical records of all vascular surgery consultations carried out in a clinical hospital between April and October 2020. The main outcome measured was the resolution of the reason for consultation. Secondary outcomes were the need to request laboratory tests or imaging, the need to evaluate the patient in person, and the need for referral to hospitalization or emergency service. Result(s): One hundred-six new consultations and their follow-up (remotely or in person) were analyzed. A definitive diagnosis could be reached in 74% of consultations, treatment could be instituted or modified in 69% of them, and the reason for consultation could be resolved in 74% of cases. Laboratory and imaging tests were requested in 36 and 63% of consultations, respectively. Four percent of patients were referred to the emergency department or hospitalization. Conclusion(s): In the vast majority of consultations, it was possible to achieve a definitive diagnosis, prescribe a treatment and resolve the reason for consultation without the need for a face-to-face medical evaluation. Copyright © 2022 Sociedad Medica de Santiago. All rights reserved.

Cleaner Skies during the COVID-19 Lockdown

During spring 2020, the COVID-19 pandemic caused massive reductions in emissions from industry and ground and airborne transportation. To explore the resulting atmospheric composition changes, we conducted the BLUESKY campaign with two research aircraft and measured trace gases, aerosols, and cloud properties from the boundary layer to the lower stratosphere. From 16 May to 9 June 2020, we performed 20 flights in the early COVID-19 lockdown phase over Europe and the Atlantic Ocean. We found up to 50% reductions in boundary layer nitrogen dioxide concentrations in urban areas from GOME-2B satellite data, along with carbon monoxide reductions in the pollution hot spots. We measured 20%-70% reductions in total reactive nitrogen, carbon monoxide, and fine mode aerosol concentration in profiles over German cities compared to a 10-yr dataset from passenger aircraft. The total aerosol mass was significantly reduced below 5 km altitude, and the organic aerosol fraction also aloft, indicative of decreased organic precursor gas emissions. The reduced aerosol optical thickness caused a perceptible shift in sky color toward the blue part of the spectrum (hence BLUESKY) and increased shortwave radiation at the surface. We find that the 80% decline in air traffic led to substantial reductions in nitrogen oxides at cruise altitudes, in contrail cover, and in resulting radiative forcing. The light extinction and depolarization by cirrus were also reduced in regions with substantially decreased air traffic. General circulation-chemistry model simulations indicate good agreement with the measurements when applying a reduced emission scenario. The comprehensive BLUESKY dataset documents the major impact of anthropogenic emissions on the atmospheric composition.

Real-world effectiveness of sofosbuvir/velpatasvir for the treatment of hepatitis C virus in prison settings

Plain language summary Achievement of elimination of HCV as a major public health threat requires focus on vulnerable populations such as people in prison. The prison population is at high risk of HCV infection but their treatment is complicated by social issues such as mental health disorders and drug use. Simple and effective treatment regimens are required to increase access to treatment and improve cure rates. This real-world analysis across Europe and Canada analyzed data from 20 prison populations. HCV-infected individuals were treated with sofosbuvir/velpatasvir, a once daily treatment which requires minimal monitoring. This regimen achieved high cure rates in the prison population despite the existence of complicating social issues. Background: People in prison are at high risk of hepatitis C virus (HCV) infection and often have a history of injection drug use and mental health disorders. Simple test-and-treat regimens which require minimal monitoring are critical. Methods: This integrated real-world analysis evaluated the effectiveness of once daily sofosbuvir/velpatasvir (SOF/VEL) in 20 prison cohorts across Europe and Canada. The primary outcome was sustained virological response (SVR) in the effectiveness population (EP), defined as patients with a valid SVR status. Secondary outcomes were reasons for not achieving SVR, adherence and time between HCV RNA diagnosis and SOF/VEL treatment. Results: Overall, 526 people in prison were included with 98.9% SVR achieved in the EP (n = 442). Cure rates were not compromised by drug use or existence of mental health disorders. Conclusion: SOF/VEL for 12 weeks is highly successful in prison settings and enables the implementation of a simple treatment algorithm in line with guideline recommendations and test-and-treat strategies.

HCV elimination in active PWID: SOF/VEL as a simple tool to implement a test and treat approach in this vulnerable population

Background: The treatment of high priority populations, including patients actively using intravenous drugs (active PWID), must be prioritized to accomplish the WHO HCV elimination goals by 2030. Simplification of the treatment cascade is key to reaching this goal, even more so in the COVID-19 era Sofosbuvir/velpatasvir (SOF/VEL) is a protease inhibitor-free, pangenotypic, panfibrotic, single duration, single tablet regimen, to be taken without regards to food and with limited drug-drug interactions This real-world analysis evaluates SOF/VEL as a simple strategy to implement a testand- treat approach in HCV-infected active PWID Methods: Adult active PWID treated for HCV with 12 weeks SOF/VEL in different clinical settings were included from 25 cohorts in 6 countries Patients with a history of decompensation or prior NS5A-inhibitor exposure were excluded The endpoints were HCV cure (undetectable HCV RNA ≥12 after the end of therapy, SVR12) and time-to-treatment (TT) between most recent HCV RNA measurement and SOF/VEL treatment start Results: Analysis included 340 patients, mean age 44±10years, 84% male, 15% compensated cirrhotic (CC) and 8% treatment-experienced, with 43% genotype (GT) 1 and 41% GT3 73% of patients were diagnosed with a mental disorder, 27% were homeless and 21% incarcerated Of patients with TT available (n=334), 10% were treated the same day of diagnosis, 16% within 1 week, 39% within 1 month, and 69% within 3 months Treatment adherence below 90% was observed in 24 patients (8%) SVR12 is available for 254 patients (75%), as non-virological or unknown cause of failure was documented in 86 patients (25%), 79% due to lost-to-follow-up (LTFU) SVR12 was 98% overall (249/254), 98% (80/82) in non-cirrhotic and 95% (20/21) in CC patients Active PWID with mental disorders showed 97% SVR12 (181/186) Of active PWID with GT3 infection, 96% (104/180) were cured, including 95% (20/21) of those with CC Of 31 patients starting treatment within 1 week of diagnosis, all achieved SVR12 compared to 126/129 (98%) starting within 3 months of diagnosis Conclusion: SOF/VEL is a simple HCV treatment resulting in high cure rates in active PWID, including patients with multiple complicating factors LTFU remains a challenge in this population The simplicity of the SOF/VEL approach allowing for shortening of the patient care cascade and rapid treatment starts with high cure rates may help address this important issue.

Time from diagnosis to treatment in vulnerable populations versus general population: Do we testand-treat our HCV patients in the same way?

Background: Stigma and poor linkage to care, amplified in the setting of the COVID-19 pandemic, are significant barriers for treating hepatitis C (HCV) in vulnerable patients, reducing our ability to implement a rapid test and treat (TnT) strategy with minimal monitoring within a simple patient cascade, as currently available HCV therapies would allow us to do This real-world analysis evaluates our ability to implement this approach in both general (GP) and vulnerable (VP) populations Methods: HCV-infected patients from 32 clinical cohorts in 8 countries treated with sofosbuvir/ velpatasvir without a history of decompensation or prior NS5A-inhibitor exposure were included in this analysis The VP included prisoners, homeless patients and patients with mental disorders Time to treatment (TT) between the most recent HCV RNA measurement and treatment initiation was estimated based on available data Results: A total of 2449 patients were included, 937 in GP (58% males), 1512 (72% males) in VP (59% with mental disorders, 31% homeless, 10% imprisoned) Mean age [standard deviation] was 55 [14] and 50 [14] years in GP and VP respectively Genotype 3 was observed in 35% and 33% respectively, compensated cirrhosis confirmed in 20% and 18% of GP versus VP. The median TT [MTT, interquartile range] was 55 days [23- 107] in GP and 60 days [27-132] in VP The longest MTT of 66 days [32-134] was observed in patients with mental disorders MTT was 63 days [29-149] in prisoners and 27 days [13-71] among the homeless Only 13% of GP and 8% of VP were treated the same day of diagnosis, and 70% of GP and 63% of VP were treated within 3 months In patients with mental disorders only 4% were treated the same day of diagnosis Cure rates were high and consistent with previously reported cure rates Conclusion: MTT varies across HCV patient groups, from over 6 months to 1 day This analysis shows that a quick treatment start is possible, both in general population and in vulnerable populations, supporting the feasibility of a TnT approach in all populations New strategies should be considered to engage patients with mental disorders in this model of care more effectively.