Rural populations facilitated early SARS-CoV-2 evolution and transmission in Missouri, USA

In the United States, rural populations comprise 60 million individuals and suffered from high COVID-19 disease burdens. Despite this, surveillance efforts are biased toward urban centers. Consequently, how rurally circulating SARS-CoV-2 viruses contribute toward emerging variants remains poorly understood. In this study, we aim to investigate the role of rural communities in the evolution and transmission of SARS-CoV-2 during the early pandemic. We collected 544 urban and 435 rural COVID-19-positive respiratory specimens from an overall vaccine-naïve population in Southwest Missouri between July and December 2020. Genomic analyses revealed 53 SARS-CoV-2 Pango lineages in our study samples, with 14 of these lineages identified only in rural samples. Phylodynamic analyses showed that frequent bi-directional diffusions occurred between rural and urban communities in Southwest Missouri, and that four out of seven Missouri rural-origin lineages spread globally. Further analyses revealed that the nucleocapsid protein (N):R203K/G204R paired substitutions, which were detected disproportionately across multiple Pango lineages, were more associated with urban than rural sequences. Positive selection was detected at N:204 among rural samples but was not evident in urban samples, suggesting that viruses may encounter distinct selection pressures in rural versus urban communities. This study demonstrates that rural communities may be a crucial source of SARS-CoV-2 evolution and transmission, highlighting the need to expand surveillance and resources to rural populations for COVID-19 mitigation.

Development of a non-target strategy for evaluation of potential biological effects of inhalable aerosols generated during purposeful room conditioning using an in vitro inhalation model

OBJECTIVES

An integrated in vitro inhalation approach was outlined to estimate potential adverse acute inhalation effects of aerosols from commercial nebulizer applications used for purposeful room conditioning such as disinfection, scenting or others. Aerosol characterization, exposure estimation and evaluation of acute biological effects by in vitro inhalation were included to generate dose-response data, allowing for determination of in vitro lowest observable adverse effect levels (LOAELs). Correlation of these to estimates of human lung deposition was included for quantitative in vitro to in vivo extrapolation approach (QIVIVE) for acute effects during human exposure.

METHODS

To test the proposed approach, a case study was undertaken using two realistic test materials. An acute in vitro inhalation setup with air-liquid interface A549-cells in an optimized exposure situation (P.R.I.T.® ExpoCube®) was used to expose cells and analysis of relevant biological effects (viability, mitochondrial membrane potential, stress, IL-8 release) was carried out.

RESULTS

The observed dose-responsive effects in a sub-toxic dose-range could be attributed to the main component of one test material and its presence in the aerosol phase of the nebulized material. QIVIVE resulted in a factor of at least 256 between the in vitro LOAEL and the estimated acute human lung exposure for this test material.

CONCLUSIONS

The case-study shows the value of the non-target in vitro inhalation testing approach especially in case of a lack of knowledge on complex product composition. It is expected that approaches like this will be of high value for product safety and environmental health in the future.

Substantiate a read-across hypothesis by using transcriptome data-A case study on volatile diketones

This case study explores the applicability of transcriptome data to characterize a common mechanism of action within groups of short-chain aliphatic α-, β-, and γ-diketones. Human reference in vivo data indicate that the α-diketone diacetyl induces bronchiolitis obliterans in workers involved in the preparation of microwave popcorn. The other three α-diketones induced inflammatory responses in preclinical in vivo animal studies, whereas beta and gamma diketones in addition caused neuronal effects. We investigated early transcriptional responses in primary human bronchiolar (PBEC) cell cultures after 24 h and 72 h of air-liquid exposure. Differentially expressed genes (DEGs) were assessed based on transcriptome data generated with the EUToxRisk gene panel of Temp-O-Seq^®. For each individual substance, genes were identified displaying a consistent differential expression across dose and exposure duration. The log fold change values of the DEG profiles indicate that α- and β-diketones are more active compared to γ-diketones. α-diketones in particular showed a highly concordant expression pattern, which may serve as a first indication of the shared mode of action. In order to gain a better mechanistic understanding, the resultant DEGs were submitted to a pathway analysis using ConsensusPathDB. The four α-diketones showed very similar results with regard to the number of activated and shared pathways. Overall, the number of signaling pathways decreased from α-to β-to γ-diketones. Additionally, we reconstructed networks of genes that interact with one another and are associated with different adverse outcomes such as fibrosis, inflammation or apoptosis using the TRANSPATH-database. Transcription factor enrichment and upstream analyses with the geneXplain platform revealed highly interacting gene products (called master regulators, MRs) per case study compound. The mapping of the resultant MRs on the reconstructed networks, visualized similar gene regulation with regard to fibrosis, inflammation and apoptosis. This analysis showed that transcriptome data can strengthen the similarity assessment of compounds, which is of particular importance, e.g., in read-across approaches. It is one important step towards grouping of compounds based on biological profiles.

SARS-CoV-2 and influenza co-infection: A cross-sectional study in central Missouri during the 2021-2022 influenza season

As SARS-CoV-2 and influenza viruses co-circulate, co-infections with these viruses generate an increasing concern to public health. To evaluate the prevalence and clinical impacts of SARS-CoV-2 and influenza A virus co-infections during the 2021-2022 influenza season, SARS-CoV-2-positive samples from 462 individuals were collected from October 2021 to January 2022. Of these individuals, 152 tested positive for influenza, and the monthly co-infection rate ranged from 7.1% to 48%. Compared to the Delta variant, individuals infected with Omicron were less likely to be co-infected and hospitalized, and individuals who received influenza vaccines were less likely to become co-infected. Three individuals had two samples collected on different dates, and all three developed a co-infection after their initial SARS-CoV-2 infection. This study demonstrates high prevalence of co-infections in central Missouri during the 2021-2022 influenza season, differences in co-infection prevalence between the Delta and the Omicron waves, and the importance of influenza vaccinations against co-infections.

Finerenone reduces renal RORgt gd T-Cells and protects against cardiorenal damage

 

Chronic activation of the mineralocorticoid receptor (MR) through the agonist aldosterone leads to pathological processes like inflammation, fibrosis, and increased blood pressure. Therefore, MR antagonists (MRA) belong to guideline-based therapy for hypertension and heart failure with reduced ejection fraction. The nonsteroidal, selective MRA finerenone (FIN) induces distinct pharmacological actions when compared to steroidal MRAs including less adverse effects and improved efficacy (e.g. anti-fibrosis). In this study, we investigated the effects of FIN in a deoxycorticosterone acetate (DOCA)-salt model which induces an increase of blood pressure and end organ damage including hypertrophy, fibrosis, and inflammatory cell infiltration in heart and kidney.

Male C57BL6/J mice were either uni-nephrectomized in addition to DOCA-pellet application (2.4mg/d) and 0.9% NaCl in the drinking water (DOCA/UNX) or received a sham operation. One week prior to the surgery, oral treatment with FIN (10mg/kg/d) or vehicle (VEH) started and lasted throughout the experiment. Five weeks after the procedure, final examinations including blood pressure (BP) measurement, urine analysis, speckle-tracking echocardiography (STE), and FACS analysis of the heart and kidney were performed.

BP was significantly reduced by FIN treatment. FACS analysis revealed a notable immune response due to DOCA/ UNX exposure. Especially infiltrating renal RORγt γδ T-Cells were upregulated, which was significantly ameliorated by the FIN-treatment. This was accompanied by an improvement of kidney function shown by a reduction of the urinary albumin/creatinine ratio in FIN-treated mice. In the heart, FIN reduced DOCA/ UNX-induced cardiac hypertrophy, cardiac fibrosis and led to an improvement of the global longitudinal strain (GLS) in the STE-analysis. Cardiac actions of FIN were not associated with a regulation of cardiac RORγt γδ T-Cells.

The present study shows cardiac and renal protective effects of FIN in a DOCA/UNX model. The cardiorenal protection was accompanied by a reduction of renal RORγt γδ T-Cells. Anti-inflammatory actions of FIN may provide a potential mechanism of its clinical efficacy recently observed in clinical trials.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer AG

SARS-CoV-2 show no infectivity at later stages in a prolonged COVID-19 patient despite positivity in RNA testing

Inpatient coronavirus disease 2019 (COVID-19) cases present enormous costs to patients and health systems in the United States. Many hospitalized patients may continue testing COVID-19 positive even after the resolution of symptoms. Thus, a pressing concern for clinicians is the safety of discharging these asymptomatic patients if they have any remaining infectivity. This case report explores the viral viability in a patient with persistent COVID-19 over the course of a 2-month hospitalization. Positive nasopharyngeal swab samples were collected and isolated in the laboratory and analyzed by quantitative reverse-transcription polymerase chain reactions (qRT-PCR), and serology was tested for neutralizing antibodies throughout the hospitalization period. The patient experienced waning symptoms by hospital day 40 and had no viable virus growth by hospital day 41, suggesting no risk of infectivity, despite positive RT-PCR results which prolonged his hospital stay. Notably, this case showed infectivity for at least 24 days after disease onset, which is longer than the discontinuation of transmission-based precautions recommended by the Center for Disease Control and Prevention. Thus, our findings suggest that the timeline for discontinuing transmission-based precautions may need to be extended for patients with severe and prolonged COVID-19 disease. Additional large-scale studies are needed to draw definitive conclusions on the appropriate clinical management for these patients. ​.

Laboratory Tests for COVID-19: A Review of Peer-Reviewed Publications and Implications for Clinical Use

Diagnostic tests for the coronavirus infection 2019 (COVID-19) are critical for prompt diagnosis, treatment and isolation to break the cycle of transmission. A positive real-time reverse-transcriptase polymerase chain reaction (RT-PCR), in conjunction with clinical and epidemiologic data, is the current standard for diagnosis, but several challenges still exist. Serological assays help to understand epidemiology better and to evaluate vaccine responses but they are unreliable for diagnosis in the acute phase of illness or assuming protective immunity. Serology is gaining attention, mainly because of convalescent plasma gaining importance as treatment for clinically worsening COVID-19 patients. We provide a narrative review of peer-reviewed research studies on RT-PCR, serology and antigen immune-assays for COVID-19, briefly describe their lab methods and discuss their limitations for clinical practice.

Viable Eimeria oocysts in poultry house litter at the time of chick placement

The purpose of this study was to determine if Eimeria oocysts recovered from litter at the time of chick placement in commercial broiler houses contained oocysts that were infectious for chickens. Over 100 litter samples were collected from 30 poultry farms representing a total of 60 different broiler houses with 9 houses sampled more than once over 1.5 yr. The samples were collected just before the placement of newly hatched chicks and after an anticoccidial drug (ACD) or Eimeria vaccine (VAC) program, and processed for counting oocysts followed by Eimeria species determination using ITS1 PCR. Broiler chicks were inoculated with recovered Eimeria oocysts to determine if the litter oocysts were viable and capable of causing patent infection. At placement, E. maxima (Emax) oocysts were detected in 70 of 75 houses after ACD program and 46 of 47 houses after VAC program. Eimeria acervulina, E. praecox, and/or E. tenella (Eapt) were detected in 75 of 75 houses after ACD program and 47 of 47 houses after VAC program. Viability testing revealed that 33.0% of broiler houses contained viable Emax oocysts, while 46.9% contained viable Eapt oocysts. During VAC programs, the concentration of Emax oocysts at placement and the total number of Emax oocysts shed by chickens in viability studies showed a very strong correlation (r = 0.83). Likewise, during ACD programs, the concentration of Eapt oocysts at placement and the total number of Eapt oocysts shed by chickens in the viability study showed a strong correlation (r = 0.62). In general, Eimeria oocyst levels at placement and number of viable oocysts shed by chickens in the viability study were similar among houses on the same farm. However, the number of Eimeria oocysts shed in the viability studies was considerably less than expected based on the number of oocysts given. These data suggest that nearly 100% of all poultry houses contain Emax and Eapt oocysts at placement with 30 to 50% of the houses containing viable Eimeria oocysts, thus possibly representing a source of the protozoa to newly hatched chicks.

Air-Liquid Interface In Vitro Models for Respiratory Toxicology Research: Consensus Workshop and Recommendations

In vitro air-liquid interface (ALI) cell culture models can potentially be used to assess inhalation toxicology endpoints and are usually considered, in terms of relevancy, between classic (i.e., submerged) in vitro models and animal-based models. In some situations that need to be clearly defined, ALI methods may represent a complement or an alternative option to in vivo experimentations or classic in vitro methods. However, it is clear that many different approaches exist and that only very limited validation studies have been carried out to date. This means comparison of data from different methods is difficult and available methods are currently not suitable for use in regulatory assessments. This is despite inhalation toxicology being a priority area for many governmental organizations. In this setting, a 1-day workshop on ALI in vitro models for respiratory toxicology research was organized in Paris in March 2016 to assess the situation and to discuss what might be possible in terms of validation studies. The workshop was attended by major parties in Europe and brought together more than 60 representatives from various academic, commercial, and regulatory organizations. Following plenary, oral, and poster presentations, an expert panel was convened to lead a discussion on possible approaches to validation studies for ALI inhalation models. A series of recommendations were made and the outcomes of the workshop are reported.

Detection of the insulating gap and conductive filament growth direction in resistive memories

Filament growth is a key aspect in the operation of bipolar resistive random access memory (RRAM) devices, yet there are conflicting reports in the literature on the direction of growth of conductive filaments in valence change RRAM devices. We report here that an insulating gap between the filament and the semiconductor electrode can be detected by the metal-insulator-semiconductor bipolar transistor structure, and thus provide information on the filament growth direction. Using this technique, we show how voltage polarity and electrode chemistry control the filament growth direction during electro-forming. The experimental results and the nature of a gap between the filament and an electrode are discussed in light of possible models of filament formation.

A randomized, placebo-controlled phase III trial of masitinib plus gemcitabine in the treatment of advanced pancreatic cancer

BACKGROUND

Masitinib is a selective oral tyrosine-kinase inhibitor. The efficacy and safety of masitinib combined with gemcitabine was compared against single-agent gemcitabine in patients with advanced pancreatic ductal adenocarcinoma (PDAC).

PATIENTS AND METHODS

Patients with inoperable, chemotherapy-naïve, PDAC were randomized (1 : 1) to receive gemcitabine (1000 mg/m(2)) in combination with either masitinib (9 mg/kg/day) or a placebo. The primary endpoint was overall survival (OS) in the modified intent-to-treat population. Secondary OS analyses aimed to characterize subgroups with poor survival while receiving single-agent gemcitabine with subsequent evaluation of masitinib therapeutic benefit. These prospectively declared subgroups were based on pharmacogenomic data or a baseline characteristic.

RESULTS

Three hundred and fifty-three patients were randomly assigned to receive either masitinib plus gemcitabine (N = 175) or placebo plus gemcitabine (N = 178). Median OS was similar between treatment-arms for the overall population, at respectively, 7.7 and 7.1 months, with a hazard ratio (HR) of 0.89 (95% CI [0.70; 1.13]. Secondary analyses identified two subgroups having a significantly poor survival rate when receiving single-agent gemcitabine; one defined by an overexpression of acyl-CoA oxidase-1 (ACOX1) in blood, and another via a baseline pain intensity threshold (VAS > 20 mm). These subgroups represent a critical unmet medical need as evidenced from median OS of 5.5 months in patients receiving single-agent gemcitabine, and comprise an estimated 63% of patients. A significant treatment effect was observed in these subgroups for masitinib with median OS of 11.7 months in the 'ACOX1' subgroup [HR = 0.23 (0.10; 0.51), P = 0.001], and 8.0 months in the 'pain' subgroup [HR = 0.62 (0.43; 0.89), P = 0.012]. Despite an increased toxicity of the combination as compared with single-agent gemcitabine, side-effects remained manageable.

CONCLUSIONS

The present data warrant initiation of a confirmatory study that may support the use of masitinib plus gemcitabine for treatment of PDAC patients with overexpression of ACOX1 or baseline pain (VAS > 20mm). Masitinib's effect in these subgroups is also supported by biological plausibility and evidence of internal clinical validation.

TRIAL REGISTRATION

ClinicalTrials.gov:NCT00789633.

Control of morphology and crystal purity of InP nanowires by variation of phosphine flux during selective area MOMBE

We present experimental results showing how the growth rate, morphology and crystal structure of Au-catalyzed InP nanowires (NWs) fabricated by selective area metal organic molecular beam epitaxy can be tuned by the growth parameters: temperature and phosphine flux. The InP NWs with 20-65 nm diameters are grown at temperatures of 420 and 480 °C with the PH3 flow varying from 1 to 9 sccm. The NW tapering is suppressed at a higher temperature, while pure wurtzite crystal structure is preferred at higher phosphine flows. Therefore, by combining high temperature and high phosphine flux, we are able to fabricate non-tapered and stacking fault-free InP NWs with the quality that other methods rarely achieve. We also develop a model for NW growth and crystal structure which explains fairly well the observed experimental tendencies.

Shadowing and mask opening effects during selective-area vapor-liquid-solid growth of InP nanowires by metalorganic molecular beam epitaxy

Indium phosphide nanowires were grown by metalorganic molecular beam epitaxy using the selective-area vapor-liquid-solid method. We show experimentally and theoretically that the size of the annular opening around the nanowire has a major impact on nanowire growth rate. In addition, we observed a considerable reduction of the growth rate in dense two-dimensional arrays, in agreement with a calculation of the shadowing of the scattered precursors. Due to the impact of these effects on growth, they should be considered during selective-area vapor-liquid-solid nanowire epitaxy.

Determination of genotoxicity by the Comet assay applied to murine precision-cut lung slices

Precision-cut lung slices (PCLSs) are an organotypic lung model that is widely used in pharmacological, physiological, and toxicological studies. Genotoxicity testing, as a pivotal part of early risk assessment, is currently established in vivo in various organs including lung, brain, or liver, and in vitro in cell lines or primary cells. The aim of the present study was to provide the three-dimensional organ culture PCLS as a new ex vivo model for determination of genotoxicity using the Comet assay. Murine PCLS were exposed to increasing concentrations of ethyl methane sulfonate 'EMS' (0.03-0.4%) and formalin (0.5-5mM). Tissue was subsequently dissociated, and DNA single-strand breaks were quantified using the Comet assay. Number of viable dissociated lung cells was between 4×10(5) and 6.7×10(5)cells/slice. Even treatment with EMS did not induce toxicity compared to untreated tissue control. As expected, DNA single-strand breaks were increased dose-dependently and significantly after exposure to EMS. Here, tail length rose from 24μm to 75μm. In contrast, formalin resulted in a significant induction of DNA cross-links. The effects induced by EMS and formalin demonstrate the usefulness of PCLS as a new ex vivo lung model for genotoxicity testing in the early risk assessment of airborne substances in the future.

Evaluation of the local temperature of conductive filaments in resistive switching materials

The resistive switching effect in metal oxides and other dielectric materials is among the leading future non-volatile memory technologies. Resistive switching is widely ascribed to the formation and rupture of conductive filaments in the oxide, which are generated by temperature-enhanced nano-scale ion migration or other thermal effects. In spite of the central role of the local filament temperature on the switching effect, as well as on the conduction and reliability physics, no measurement methods of the filament temperature are yet available. In this work, we report on a method for evaluating the conducting filament temperature, using a metal-insulator-semiconductor bipolar transistor structure. The filament temperature is obtained by analyzing the thermal excitation rate of electrons from the filament Fermi level into the conduction band of a p-type semiconductor electrode. Measurements were carried out to obtain the conductive filament temperature in hafnia at varying ambient temperatures in the range of 3-300 K. Significant Joule heating of the filament was observed across the entire measured ambient temperature range. The extracted temperatures provide physical insight into the resistive switching effect.

No correlation between lithium serum levels and psychopathological features during the euthymic interval of patients with recurrent affective disorder

INTRODUCTION

The aim of this prospective study was to investigate the influence of lithium serum levels on subclinical psychopathological features during the euthymic interval in patients with an affective disorder.

METHODS

The study included 54 patients with a recurrent affective disorder undergoing a continuous prophylactic lithium treatment (31 unipolar, 23 bipolar). The observation period lasted for 2 years and included 332 visits. Visits consisted of a detailed interview, a continuous measurement of lithium levels and the collection of validated scales including HAMD, YMRS, CGI, VAMS and the SCL-90R. Several correlations between lithium serum levels and different psychopathological features during the euthymic interval were calculated on an individual patient basis and on a group basis to reveal generally occurring correlations.

RESULTS

No generally occurring significant correlations between lithium serum levels and specific psychopathological features were found. Only on a single patient level, 32 significant correlations between lithium level and specific psychopathological features were found, partly indicating a negative and partly indicating a positive influence of higher lithium levels on psychopathological symptoms. Nevertheless, in the group analyses no significant correlations were found.

DISCUSSION

Higher lithium levels were not associated with an improved psychopathological status, but they were not associated with a worse status (due to a higher burden of side effects) either. According to the literature there is currently no strong evidence to treat patients with a higher lithium level. It is recommended to start with a lower level and to continue with individual adjustments in accordance to prophylactic efficacy and tolerability.

Effects of lithium on the HPA axis in patients with unipolar major depression

Background

(I)

Design and methods

Three 4-week studies with each 30 acutely depressed patients (unipolar, SCID I confirmed) were conducted. In study 1, patients refractory to a treatment trial with an antidepressant of at least four weeks were treated with lithium augmentation. In study 2 and 3, drug free patients were treated with lithium monotherapy or citalopram monotherapy respectively. Weekly HAM-D ratings were performed. In each study, the DEX/CRH test was conducted right before and four weeks after initiation of the pharmacotherapy.

Results

All three pharmacological strategies showed good antidepressive efficacy. Both lithium monotherapy and lithium augmentation led to a (for most parameters significant) increase in the HPA axis activity. In contrast, citalopram monotherapy resulted in a decrease of the hormone response to the DEX/CRH test.

Mechanisms Causing Capacity Loss on Long Term Storage in NiMH System

Capacity recovery after long term storage and loaded storage is a critical issue with the NiMH system since its inception. A measurable loss in capacity is observed when cells are stored for long periods of time or discharged deeply to zero volts. The different mechanisms that are known to cause self discharge and capacity loss after storage and loaded storage will be the focus of this paper. Capacity loss after long term storage involves two main events. One is self discharge which causes the open circuit voltage(OCV) of the cell to drop. Self discharge is caused by decomposition of NiOOH, migration of metal ions and possible degradation of separator. Self discharge can be prevented by using separators which are stable at high temperatures and pH and have good ion trapping capability. Various separator types and treatments can play an important role in inhibiting metal ions from migrating thus reducing self discharge. Self discharge during storage causes a severe suppression in the voltage of the foam positive electrode. This drop in voltage causes a breakdown of the cobalt conductive network in the nickel positive electrode. Reduction of high valence cobalt(III) which forms the electrode's conductive network takes place at these low voltages. A permanent breakdown in the conductive network results in low efficiency of the cell on consecutive charge and discharge cycles. In addition, the cobalt in its lower valence states can migrate away from the electrode into the separator causing shorts. These events effect the charge and discharge efficiency of these cells thereby resulting in capacity loss. Various mechanisms causing self discharge which affect capacity recovery after long term storage and loaded storage are discussed in this paper.

Comparison of Eimeria species distribution and salinomycin resistance in commercial broiler operations utilizing different coccidiosis control strategies

The purpose of the present study was to evaluate the species composition and salinomycin sensitivity of Eimeria oocysts isolated from commercial broiler farms that differed by means of coccidiosis control (anticoccidial drugs [ACD] vs. live oocyst vaccines [VAC]). A comparison of Eimeria species composition and salinomycin sensitivity was also made before and after a producer switched from salinomycin to live oocyst vaccines. In general, no significant difference was observed in the concentration of Eimeria spp. oocysts in litter from VAC-utilizing farms compared to litter from ACD-utilizing farms. Application of PCR-based methods to detect coccidia found that Eimeria species distribution in litter from VAC operations more closely resembled the species composition in the live oocyst vaccines. Drug sensitivity testing found that Eimeria oocysts from VAC operations displayed greater salinomycin sensitivity as measured by weight gain and feed conversion efficiency compared to oocysts from ACD farms. These findings provide additional evidence for the usefulness of live oocyst vaccines to restore ionophore sensitivity in poultry operations that contain an ionophore-resistant population of Eimeria spp. oocysts.

Comparative assessment of toxicities of mainstream smoke from commercial cigarettes

Three cigarette types were compared using an experimental approach for quantifying selected toxicological effects of diluted fresh whole cigarette mainstream smoke in vitro. The test procedure involved automatic smoking of cigarettes according to the FTC/ISO standard, online monitoring of generated smoke aerosols with respect to particulate and gas-phase components, and direct exposure of a human type II-like lung cell line (A549) using exposure conditions relevant to human smoking. Test specimens were the K1R4F standard research cigarettes (9.2 mg tar/cigarette) and two commercial European light filter cigarettes (brand 1, brand 2) having the same tar content (7.0 mg/cigarette). As a representative of the toxicological effect of smoke, intracellular reduced glutathione was analyzed directly after exposure of cells. Results revealed statistically significant different quantitative effects with regard to glutathione depletion when comparing whole smoke and filtered smoke from all three cigarettes. ED50 values revealed a depletion of reduced glutathione by brand 1 cigarettes that was more than twice the depletion caused by brand 2 cigarettes on a per cigarette basis. Also, quantitatively different effects were found on a per particle and on a per CO concentration basis using whole or filtered smoke from the cigarettes. We conclude that the methods we employed provide sensitive and reproducible ways of detecting differences in the toxicological action of smoke from various types of cigarettes.

Troponin I in Patients without Chest Pain

Background: Testing for troponin has important clinical value for patients who present with typical symptoms of acute coronary syndromes (ACS) such as chest pain (CP). Much less is known about the value of troponin testing for patients who present with other symptoms of ACS (anginal equivalent symptoms).

Methods: The utilization and prognostic value of cardiac troponin I (cTnI) were evaluated at a Veterans Affairs Acute Care Facility. Clinical charts of 1184 predominantly male patients, who submitted specimens for initial cTnI testing by AxSYM, were evaluated for demographic data, cardiovascular risk factors, major diseases, and complaints at the time of testing. The endpoint was defined as all-cause death during a 200-day period after initial testing.

Results: Sixty-one percent of cTnI tests were ordered for patients who did not present with CP. Patients presenting with symptoms other than CP did not have significantly lower plasma cTnI than patients with CP. However, patients with symptoms other than CP were rarely diagnosed with ACS unless cTnI was ≥2 μg/L. The mortality during the follow-up period was severalfold higher among patients presenting with symptoms other than CP (CP, 6%; without CP, 22%; P <0.0001, χ2 test). cTnI ≥0.2 μg/L provided significant additional predictive information for patients who presented with anginal equivalent symptoms such as shortness of breath or general weakness.

Conclusion: Patients with anginal equivalent symptoms of ACS and low-positive cTnI are less often diagnosed with ACS and have a higher mortality than patients with CP.

An improved in vitro model for testing the pulmonary toxicity of complex mixtures such as cigarette smoke

Numerous approaches have been employed for testing the biological activity of cigarette smoke in vitro. None of them has managed to expose cultured lung cells in a realistic manner to the complex gaseous and particulate mixture that constitutes cigarette smoke. We have devised a system that makes this possible. The system presented here enables the direct exposure of human lung cells to native, unmodified cigarette mainstream smoke. It consists of a smoking machine, a dilution device for the smoke, analytical devices for online monitoring and a specially adapted exposure module based on the Cultex** cell cultivation system that is equipped with a gas-exposure top. Due to the special design of the exposure device and the optimised exposure conditions, this equipment allows cultured human lung cells to be exposed to freshly generated cigarette mainstream smoke. Exploratory experiments revealed that the smoke could be diluted over a wide concentration range in a reproducible way with respect to gas and particulate phases, and also demonstrated reproducible particle deposition depending on smoke concentration. Furthermore, it was shown that the exposed cells maintained their viability. Native cigarette mainstream smoke induced dose-dependent cellular effects in exposed cells with respect to cellular viability (viable cell number monitored by tetrazolium salt cleavage) and intracellular parameters (ATP and glutathione content). Therefore, fresh, physically and chemically unmodified cigarette mainstream smoke can be tested using this novel system.

Novel approaches for studying pulmonary toxicity in vitro

The in vitro study of adverse cellular effects induced by inhaled pollutants poses a special problem due to the difficulties of exposing cultured cells of the respiratory tract directly to test atmospheres that can include complex gaseous and particulate mixtures. In general, there is no widely accepted in vitro exposure system. However, in vitro methods offer the unique possibility for use of human cells, developed and validated cell culture and exposure device (CULTEX(1)) using the principle of the air/liquid exposure technique. Cells of the respiratory tract are grown on porous membranes in transwell inserts. After removal of the medium, the cells can be treated on their superficial surfaces with the test atmosphere, and at the same time they are supplied with nutrients through the membrane below. In comparison with other experimental approaches, the goal of our studies is to analyze the biological effects of test atmospheres under environmental conditions, i.e. without humidifying the atmosphere or adding additional CO(2). The system used is small and flexible enough independent of a cultivation chamber and thus offers the opportunity for onsite study of indoor and outdoor atmospheres in the field. The efficacy of the exposure device has already been demonstrated in the analysis of dose-dependent cytotoxic and genotoxic effects of exposure of epithelial lung cells to complex mixtures such as native diesel exhaust and side-stream smoke.

Exposure of human lung cells to inhalable substances: a novel test strategy involving clean air exposure periods using whole diluted cigarette mainstream smoke

An experimental approach was established for the validation of an in vitro test system for complex environmental test atmospheres consisting of both gaseous substances and particulates. Smoke from two different cigarette types (generated by an automatic cigarette-smoking machine) was employed to assess both the sensitivity and the specificity of the system. The smoke was diluted with synthetic air and used to expose human lung cells grown on microporous membranes. Cells were exposed alternately to diluted cigarette smoke and pure synthetic air. The effect of diluted smoke was assessed without humidification, addition of CO2, or any other physical or chemical modification of the smoke. The experimental setup included online monitoring of the gas phase (by analysis of CO concentration) and particulate phase (by light-scattering photometry). Replicate experiments confirmed a reproducible generation and dilution of the smoke and a smoke age of about 7 s at the time it came into contact with the cells. Experiments using human lung cells revealed that smoke from the two different cigarette types induced different levels of dose-dependent toxicity. A cell exposure of 6 min using 6 alternating smoke and synthetic air periods was sufficient to cause different effects as measured by intracellular glutathione content. The fact that the system could differentiate between two different types of cigarette smoke demonstrated its high sensitivity and specificity. The system offers new ways to test native complex gaseous and aerosol mixtures in vitro using short exposure times and very small amounts of test substances.

Macro-aspartate aminotransferase in a female with antibodies to hepatitis C virus

Persistent elevation of aspartate aminotransferase (AST) activity in serum due to the presence of a macroenzyme form of AST (macro-AST) may lead to diagnostic confusion in many clinical conditions, particularly those associated with chronic liver disease. We describe a case of macro-AST arising in an adult female with a false-positive hepatitis C virus (HCV) RNA test result that was not accompanied by other biochemical or histologic evidence of liver disease. The presence of macro-AST in serum was confirmed utilizing size-exclusion, high performance liquid chromatography (HPLC) and Protein G-agarose beads to precipitate immune complexes of AST and immunoglobulin G followed by centrifugation and AST activity measurements in the supernatant. A brief review of the clinical enzymology of AST and methods used to quantify serum macro-AST activity is provided.

A method for the in vitro exposure of human cells to environmental and complex gaseous mixtures: application to various types of atmosphere

The application of in vitro methods to the analysis of the effects of airborne materials is still limited, because there are no generally accepted concepts and technologies for efficiently exposing adherent growing cells to test atmospheres, especially those comprising complex mixtures of gaseous and particulate phases. The introduction of in vitro research into the field of inhalation toxicology offers a unique possibility for using human cells and tissues for pre-screening studies, thus reducing the necessity for animal experiments, and cutting the numbers of animals used in toxicological testing. We therefore developed a novel experimental concept that uses an exposure device based on the cell cultivation system CULTEX (Patent No. DE 198011763; PCT/EP99/00295). This allowed us to investigate environmental atmospheres, which were chemically and physically unmodified, in an in vitro system, by exposing the target cells directly at the air/liquid interface. The exposure device itself is small and flexible enough to be connected to a variety of aerosol-generating systems without the need for an incubator, as it fulfils all the requirements for maintaining cell viability over a defined period. The general applicability and the sensitivity of this in vitro approach for testing various generated atmospheres under the same cell-exposure conditions were demonstrated by studying dose-dependent cytotoxic effects in human lung epithelial cells exposed to air contaminated with single gases or complex mixtures, such as diesel exhaust fumes and side-stream cigarette smoke.