Optimization of Aspergillus versicolor Culture and Aerosolization in a Murine Model of Inhalational Fungal Exposure

Aspergillus versicolor is ubiquitous in the environment and is particularly abundant in damp indoor spaces. Exposure to Aspergillus species, as well as other environmental fungi, has been linked to respiratory health outcomes, including asthma, allergy, and even local or disseminated infection. However, the pulmonary immunological mechanisms associated with repeated exposure to A. versicolor have remained relatively uncharacterized. Here, A. versicolor was cultured and desiccated on rice then placed in an acoustical generator system to achieve aerosolization. Mice were challenged with titrated doses of aerosolized conidia to examine deposition, lymphoproliferative properties, and immunotoxicological response to repeated inhalation exposures. The necessary dose to induce lymphoproliferation was identified, but not infection-like pathology. Further, it was determined that the dose was able to initiate localized immune responses. The data presented in this study demonstrate an optimized and reproducible method for delivering A. versicolor conidia to rodents via nose-only inhalation. Additionally, the feasibility of a long-term repeated exposure study was established. This experimental protocol can be used in future studies to investigate the physiological effects of repeated pulmonary exposure to fungal conidia utilizing a practical and relevant mode of delivery. In total, these data constitute an important foundation for subsequent research in the field.

Aerosol physicochemical determinants of carbon black and ozone inhalation co-exposure induced pulmonary toxicity

Air pollution accounts for more than 7 million premature deaths worldwide. Using ultrafine carbon black (CB) and ozone (O3) as a model for an environmental co-exposure scenario, the dose response relationships in acute pulmonary injury and inflammation were determined by generating, characterizing, and comparing stable concentrations of CB aerosols (2.5, 5.0, 10.0 mg/m3), O3 (0.5, 1.0, 2.0 ppm) with mixture CB + O3 (2.5 + 0.5, 5.0 + 1.0, 10.0 + 2.0). C57BL6 male mice were exposed for 3 h by whole body inhalation and acute toxicity determined after 24 h. CB itself did not cause any alteration, however, a dose response in pulmonary injury/inflammation was observed with O3 and CB + O3. This increase in response with mixtures was not dependent on the uptake but was due to enhanced reactivity of the particles. Benchmark dose modeling showed several-fold increase in potency with CB + O3 compared with CB or O3 alone. Principal component analysis provided insight into response relationships between various doses and treatments. There was a significant correlation in lung responses with charge-based size distribution, total/alveolar deposition, oxidant generation, and antioxidant depletion potential. Lung tissue gene/protein response demonstrated distinct patterns that are better predicted by either particle dose/aerosol responses (interleukin-1β, keratinocyte chemoattractant, transforming growth factor beta) or particle reactivity (thymic stromal lymphopoietin, interleukin-13, interleukin-6). Hierarchical clustering showed a distinct signature with high dose and a similarity in mRNA expression pattern of low and medium doses of CB + O3. In conclusion, we demonstrate that the biological outcomes from CB + O3 co-exposure are significantly greater than individual exposures over a range of aerosol concentrations and aerosol characteristics can predict biological outcome.

Characterization of an Electronic Nicotine Delivery System (ENDS) Aerosol Generation Platform to Determine Exposure Risks

Evaluating vaping parameters that influence electronic nicotine delivery system (ENDS) emission profiles and potentially hazardous exposure levels is essential to protecting human health. We developed an automated multi-channel ENDS aerosol generation system (EAGS) for characterizing size-resolved particle emissions across pod- and mod-type devices using real-time monitoring instruments, an exposure chamber, and vaping parameters including different ventilation rates, device type and age, e-liquid formulation, and atomizer setup. Results show the ENDS device type, e-liquid flavoring, and nicotine content can affect particle emissions. In general, pod-type devices have unimodal particle size distributions and higher number emissions, while mod-type devices have bimodal size distributions and higher mass emissions. For pod-type devices, later puff fractions emit lower aerosols, which is potentially associated with the change of coil resistance and power during ageing. For a mod-type device, an atomizer with a lower resistance coil and higher power generates larger particle emissions than an atomizer with a greater resistance coil and lower power. The unventilated scenario produces higher particle emission factors, except for particle mass emission from pod-type devices. The data provided herein indicate the EAGS can produce realistic and reproducible puff profiles of pod- and mod-type ENDS devices and therefore is a suitable platform for characterizing ENDS-associated exposure risks.

Liver development is restored by blastocyst complementation of HHEX knockout in mice and pigs

Background

There are over 17,000 patients in the US waiting to receive liver transplants, and these numbers are increasing dramatically. Significant effort is being made to obtain functional hepatocytes and liver tissue that can for therapeutic use in patients. Blastocyst complementation is a challenging, innovative technology that could fundamentally change the future of organ transplantation. It requires the knockout (KO) of genes essential for cell or organ development in early stage host embryos followed by injection of donor pluripotent stem cells (PSCs) into host blastocysts to generate chimeric offspring in which progeny of the donor cells populate the open niche to develop functional tissues and organs.

Methods

The HHEX gene is necessary for proper liver development. We engineered loss of HHEX gene expression in early mouse and pig embryos and performed intraspecies blastocyst complementation of HHEX KO embryos with eGFP-labeled PSCs in order to rescue the loss of liver development.

Results

Loss of HHEX gene expression resulted in embryonic lethality at day 10.5 in mice and produced characteristics of lethality at day 18 in pigs, with absence of liver tissue in both species. Analyses of mouse and pig HHEX KO fetuses confirmed significant loss of liver-specific gene and protein expression. Intraspecies blastocyst complementation restored liver formation and liver-specific proteins in both mouse and pig. Livers in complemented chimeric fetuses in both species were comprised of eGFP-labeled donor-derived cells and survived beyond the previously observed time of HHEX KO embryonic lethality.

Conclusions

This work demonstrates that loss of liver development in the HHEX KO can be rescued via blastocyst complementation in both mice and pigs. This complementation strategy is the first step towards generating interspecies chimeras for the goal of producing human liver cells, tissues, and potentially complete organs for clinical transplantation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02348-z.

Electronic Cigarettes and Vaping-Associated Lung Injury (EVALI): A Rural Appalachian Experience

Background: Electronic cigarette use has increased dramatically since their introduction in 2007. Respiratory complications, particularly lipoid pneumonia, have been reported as early as 2012. An outbreak of pulmonary injury in 2019 has been reported in patients using vaping products.Research Question: To describe a rural Appalachian tertiary center's experience of EVALI and to identify novel mechanisms of pulmonary injury patterns.Study Design and Methods: We present a consecutive case series of 17 patients admitted to our rural, academic, tertiary care institution with EVALI from August 2019 to March 2020. Demographics, baseline characteristics, co-morbidities, vaping behavior, and hospital course were recorded. Broncho-alveolar lavage specimens were assessed for lipid-laden macrophages and hemosiderin-laden macrophages with stains for Oil-Red-O (n = 15) and Prussian Blue (n = 14) respectively.The patient volunteered e-liquid materials (n = 6), and vapors were analyzed using a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) to describe the chemical profile. Post-discharge interviews were conducted.Results: The most common CT finding was bilateral ground-glass opacities with a predilection for lower lung zones. The most frequent pulmonary injury pattern was lipoid pneumonia. The majority of EVALI patients were critically ill requiring ventilation or ECMO. The most severely ill patients were noted to be positive for iron stains in macrophages and showed higher volatile organic compound (VOC) levels in chemical analysis.Interpretation: Based on our experience, EVALI in rural Appalachia presented with relatively severe respiratory failure. Worse outcomes appear to be correlated to high levels of VOCs, iron deposition in lungs, and concomitant infection.

Testicular organoids to study cell-cell interactions in the mammalian testis

BACKGROUND

Over the last ten years, three-dimensional organoid culture has garnered renewed interest, as organoids generated from primary cells or stem cells with cell associations and functions similar to organs in vivo can be a powerful tool to study tissue-specific cell-cell interactions in vitro. Very recently, a few interesting approaches have been put forth for generating testicular organoids for studying the germ cell niche microenvironment.

AIM

To review different model systems that have been employed to study germ cell biology and testicular cell-cell interactions and discuss how the organoid approach can address some of the shortcomings of those systems.

RESULTS AND CONCLUSION

Testicular organoids that bear architectural and functional similarities to their in vivo counterparts are a powerful model system to study cell-cell interactions in the germ cell niche. Organoids enable studying samples in humans and other large animals where in vivo experiments are not possible, allow modeling of testicular disease and malignancies and may provide a platform to design more precise therapeutic interventions.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Urinary Benzo[a]pyrene and Its Metabolites as Molecular Biomarkers of Asphalt Fume Exposure Characterized by Microflow LC Coupled to Hybrid Quadrupole Time-of-Flight Mass Spectrometry

As a step to study the health effects of asphalt fume exposure, an analytical method was developed to characterize benzo[a]pyrene and its hydroxy metabolites in the urine of asphalt fume-exposed rats. This method is based on microflow liquid chromatography (LC) coupled to hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometry (Q-TOFMS). Twenty-four female Sprague-Dawley rats were used in the experiment, with 8 as controls and 16 exposed to asphalt fumes in a whole-body inhalation chamber for 10 days (4 h/day). Generated at 150 degrees C, the asphalt fume concentration in the animal exposure chamber ranged 76-117 mg/m(3). In the urine of the asphalt fume-exposed rats, benzo[a]pyrene and its metabolites of 3-hydroxybenzo[a]pyrene, benzo[a]pyrene-7,8-dihydrodiol(+/-), and benzo[a]pyrene-7,8,9,10-tetrahydrotetrol(+/-) were identified, and their concentrations were determined at 2.19 +/- 0.49, 16.17 +/- 0.3, 6.28 +/- 0.36, and 29.35 +/- 0.26 ng/100 mL, respectively. The metabolite concentrations from the controlled group, however, were either under the detection limits or at a relatively very low level (0.19 +/- 0.41 ng/100 mL for benzo[a]pyrene-7,8,9,10-tetrahydrotetrol metabolite). The results clearly indicate that the benzo[a]pyrene and its hydroxy metabolites were significantly elevated (p < 0.001) in the urine of asphalt fume-exposed rats relative to controls. The study also demonstrated that the combination of microflow LC separation and collision-induced dissociation leading to a characteristic fragmentation pattern by hybrid Q-TOFMS offers a distinct advantage for the identifications and characterizations of the benzo[a]pyrene metabolites.

Metal working fluids: sub-chronic effects on pulmonary functions in B6C3F1 mice given vitamin E deficient and sufficient diets

Metal working fluids (MWFs) have been widely known to cause asthma and neoplasia of the larynx, pancreas, rectum, skin and urinary bladder (Textbook of Clinical Occupational and Environmental Medicine (1994) 814; Am. J. Ind. Med. 32 (1997) 240; Am. J. Ind. Med. 33 (1997) 282; Am. J. Ind. Med. 22 (1994) 185). Other non-neoplastic respiratory effects in industrial workers attributed to MWFs include increased rates of cough, phlegm production, wheeze, chronic bronchitis and chest tightness (Eur. J. Resir. Dis. 63(118) (1982), 79; J. Occup. Med. 24 (1982) 473; Am. J. Ind. Med. 32 (1997) 450). The epidemic and endemic nature of immune mediated lung morbidity commonly known as hypersensitivity pneumonitis in workers from several different industries using MWFs has been well documented (J. Allergy clin. Immunol. 91 (1993) 311; Chest 108 (1995) 636; MMWR45 (1996) 606; Am. J. Ind. Med. 32 (1997) 423). We studied morphological/functional and antioxidant outcomes in lungs after inhalation exposure of vitamin E deficient mice to MWF (27 mg m(-3) 17 weeks, 5 days a week, 6 h a day). Mice were given vitamin E deficient (<10 IU kg(-1) vitamin E) or basal diets (50 IU kg(-1) vitamin E) for 35 weeks. Inhalation exposure to MWF started after 18 weeks on diet. Microscopic observation of lungs from mice given vitamin E deficient or sufficient diets revealed no inflammation or morphological alteration after exposure to MWF. Mice given vitamin E deficient diet exhibited a significant decrease (P<0.05) in breathing rate, peak inspiratory/expiratory flow, minute ventilation, and tidal volume compared with sufficient controls. However, no differences were found after exposure to MWF in pulmonary function, with the exception of tidal volume which also significantly decreased (P<0.05). Exposure to MWF reduced vitamin E, protein thiol and ascorbate level in lungs. Exposure to MWF in combination with a vitamin E deficient diet resulted in significantly enhanced accumulation of peroxidative products compared with vitamin E deficient controls. This is the first report that describes the increase of oxidative stress in the lungs after MWF exposure.

Characterization of asphalt fume composition under simulated road paving conditions by GC/MS and microflow LC/quadrupole time-of-flight MS

A highly sensitive, selective, and reliable analytical method has been developed and validated for characterization of asphalt fume generated under simulated road paving conditions. A dynamic asphalt fume generation system was modified to provide consistent test atmospheres at simulated asphalt road paving conditions. In the process of fume generation, asphalt was initially preheated in an oven to 170 degrees C, pumped to a large kettle, which maintained the asphalt temperature between 150 and 170 degrees C, and then transferred to the generator. The fume was conducted from the generator to an exposure chamber through a heated transfer line. Characterization of the asphalt fume test atmospheres included the following: (1) determination of the consistency of the asphalt aerosol composition within the generation system; (2) quantification of total organic matter of the asphalt fume by electron impact ionization of isotope dilution gas chromatography/ mass spectrometry); and (3) identification of individual priority polycyclic aromatic hydrocarbons (PAHs) in asphalt fume by selected ion monitoring. With the developed method, asphalt fumes could be characterized into three fractions: (1) filter collection of a large molecular size fraction over a range of mass-to-charge (m/z) ratios of 173-309; (2) XAD-2 trapping of a medium molecular size fraction over a range of m/z ratios of 121-197; and (3) charcoal trapping of a small molecular size fraction that contained mainly the volatile vapor fraction over a range of m/z ratios of 57-141. Total organic matter of the asphalt fume was quantified over the 5 exposure days. Sixteen specific priority PAHs were monitored and identified. These PAHs were determined at trace levels on the filter fraction. A novel approach, which utilizes collision-induced dissociation of fragmentation pathway leading to a characteristic fragmentation pattern by coupling microflow liquid chromatography to atmospheric pressure chemical ionization of quadrupole time-of-flight mass spectrometry, was used to further clarify the trace amount of key components present in simulated road paving asphalt fumes. These results demonstrate that asphalt fume composition could be characterized and specific priority PAHs could be identified by this method. The major advantages of this method are its highly sensitivity, selectivity, and reliability for chemical hazard characterization in a complex mixture. This method is suitable for support toxicity studies using simulated occupational exposure to asphalt fumes.

PACT, a stress-modulated cellular activator of interferon-induced double-stranded RNA-activated protein kinase, PKR

The interferon (IFN)-induced, double-stranded (ds)RNA-activated serine-threonine protein kinase, PKR, is a key mediator of the antiviral activities of IFNs. In addition, PKR activity is also involved in regulation of cell proliferation, apoptosis, and signal transduction. In virally infected cells, dsRNA has been shown to bind and activate PKR kinase function. Implication of PKR activity in normal cellular processes has invoked activators other than dsRNA because RNAs with perfectly duplexed regions of sufficient length that are able to activate PKR are absent in cellular RNAs. We have recently reported cloning of PACT, a novel protein activator of PKR. PACT heterodimerizes with PKR and activates it by direct protein-protein interaction. Overexpression of PACT in mammalian cells leads to phosphorylation of the alpha subunit of the eukaryotic initiation factor 2 (eIF2alpha), the cellular substrate for PKR, and leads to inhibition of protein synthesis. Here, we present evidence that endogenous PACT acts as a protein activator of PKR in response to diverse stress signals such as serum starvation, and peroxide or arsenite treatment. Following exposure of cells to these stress agents, PACT is phosphorylated and associates with PKR with increased affinity. PACT-mediated activation of PKR leads to enhanced eIF2alpha phosphorylation followed by apoptosis. Based on the results presented here, we propose that PACT is a novel stress-modulated physiological activator of PKR.

Use of the radial forearm fasciocutaneous free flap and montgomery salivary bypass tube for pharyngoesophageal reconstruction

BACKGROUND

Head and neck reconstructive surgeons involved in pharyngoesophageal reconstruction have several options available to repair the defect after partial or total laryngopharyngectomy. There is no uniform agreement among head and neck surgeons as to which of the most frequently used techniques offers the best results.

METHODS

A retrospective study was performed on 20 consecutive patients who had undergone reconstruction of the hypopharynx and cervical esophagus using a radial forearm free flap with Montgomery salivary bypass tube at the Massachusetts Eye and Ear Infirmary in Boston, Massachusetts, and St. Louis University, Department of Otolaryngology-Head and Neck Surgery between 1992 and 1996. This reconstruction was used for primary reconstruction after total or partial laryngopharyngectomy with cervical esophagectomy, partial pharyngectomy sparing the larynx, and for reconstruction of the stenotic neopharynx after laryngectomy.

RESULTS

The overall rate of pharyngocutaneous fistula was 20%, and the rate of postoperative stricture was 10%. Of patients reconstructed with this technique, 85% were able to resume oral alimentation, whereas 15% remained G-tube dependent. Of the 18 patients who did not have their larynges remain intact, 6 were able to develop useful tracheoesophageal speech.

CONCLUSIONS

The results of this study show that the radial forearm fasciocutaneous free flap in combination with the Montgomery salivary bypass tube is extremely useful for reconstruction of partial and circumferential defects of the hypopharynx and cervical esophagus.

Acute inflammatory reaction in rats after intratracheal instillation of material collected from a nylon flocking plant

Several cases of interstitial lung disease have been diagnosed among workers at a nylon flock plant, but the etiologic agent for the disease outbreak was unknown. The results of a medical survey and industrial hygiene study indicated that the dust present in the plant may be responsible. Thus, airborne dust collected at the plant was examined for its inflammatory potential in rat lungs. The endpoints measured were: (1) breathing rates, (2) differential cell counts of bronchoalveolar lavage cells, (3) alveolar macrophage (AM) chemiluminescence, (4) albumin concentration and matrix metalloprotease activities in the acellular fluid from the initial bronchoalveolar lavage, and (5) pulmonary histopathology. In the first study, rats received a single dose of the airborne dust sample (10 mg/kg body weight) by intratracheal (IT) instillation. At 1 d post-IT, all inflammatory endpoints were significantly increased versus controls, but by 29 d post-IT they did not differ significantly from controls. Histopathology demonstrated mild to moderate, multifocal, suppurative pneumonia, usually centered around bronchioles, at 1 d post-IT. At 29 d post-IT, pulmonary inflammation was minimal to mild and characterized by alveolar histocytosis usually restricted to the immediate area of retained bire-fringent fibers. In subsequent experiments, airborne dust was extracted with water and the dust (washed airborne dust) and water extract (soluble fraction) were separated by centrifugation for further study. Nylon tow dust was prepared in the laboratory by milling uncut nylon strands (called tow) that had not been treated with the finish or dyes that are commonly used in the flock plants. Rats were administered a single dose of a dust sample (10 mg/kg body weight) or the soluble fraction (1.3 ml/kg body weight) by IT administration and the same endpoints were measured at 1 d post-IT. The dust samples caused significant increases in all of the inflammatory endpoints; however, the soluble fraction was much less active. Histological analysis of the lungs 1 d post-IT confirmed lung inflammation was occurring and tended to center around bronchioles. The results suggest that: (1) nylon flocking generates particles of respirable size that can interact with AM in the lung and can be detected in the lung 29 d after exposure, (2) the dust samples examined cause an inflammatory response, (3) water-extractable agent(s) from airborne dust contribute only minimally to the inflammatory response, and (4) the acute inflammatory response to these dusts is substantial when compared to other pathologic occupational dusts previously examined in our laboratory.