Does exposure to ammonia concentrations lower than the threshold limit value cause acute pulmonary effects?

One of the major toxic effects of exposure to ammonia is the resulting pulmonary acute and chronic effects. This study investigated the acute pulmonary effects of exposure to ammonia lower than the recommended threshold limit value (TLV). This cross-sectional study was conducted in 2021 in four chemical fertilizer production industries using ammonia as the main raw material. A total of 116 workers who were exposed to ammonia were investigated. The level of exposure to ammonia was measured by NMAM 6016, and the evaluation of pulmonary symptoms and function parameters was done using the American Thoracic Society and European Respiratory Society protocols in four sessions. The paired-sample t-test, repeated measures test, Chi-square, and Fisher's exact test were run to analyze the collected data. The prevalence rates of pulmonary symptoms, including cough, dyspnea, phlegm, and wheezing, were 24.14, 17.24, 14.66, and 16.38%, respectively, after one exposure shift. It was observed that all pulmonary function parameters were reduced after one exposure shift to ammonia. The results revealed that the parameters of vital capacity, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), the FEV1/FVC ratio, and peak expiratory flow significantly decreased (p < 0.05) across four exposure shifts. The findings indicated that exposure to ammonia at concentrations lower than one-fifth of TLV could bring about acute pulmonary effects and reduce pulmonary function parameters, similar to the pattern observed in obstructive pulmonary diseases.

Talc Inhalation in Rats and Humans: A Review and Appraisal of Available Evidence

BACKGROUND

Current information on the health effects and toxicology of talc suggests that this may lead to a specific target organ toxicity arising from repeated exposure (STOT-RE) classification.

OBJECTIVE

To provide an assessment of the currently available inhalation toxicity data on talc and to put these data in the perspective of other poorly soluble low-toxicity particles.

METHODS

A database of 177 articles was gathered from different sources.

RESULTS

Relevant animal data sets were subjected to a quality review, and epidemiological studies on talc and lung effects published since 2016 were reviewed.

CONCLUSIONS

Of nine original inhalation studies reviewed, only one study using rats and mice met the criteria that are needed to include for a reliable evaluation for STOT-RE. Together with the pulmonary effects observed in exposed talc miners, a STOT-RE 1 classification is warranted.

[Foil Smoking/Heroin Inhalation]

Foil Smoking/Heroin Inhalation Abstract. Foil smoking is generally heroin consumption by inhalation. By heating an aluminum foil with a fire lighter the heroin on top of the foil starts melting and the smoke is then inhaled using a straw. Foil smoking is the second most common form of heroin consumption after the intravenous use. In contrast to the IV administration, heroin inhalation effects are delayed by a few minutes and the risk of transmission of HIV, Hepatitis or other infectious diseases is not relevant. Severe bronchospasms can occur in patients with or without prior pulmonary disease such as asthma bronchiale. One cerebral consequence of foil smoking is leukoencephalopathy, a spongiform degeneration of the white matter. This is likely triggered by the pyrolysate generated during the heating process. Multiple drug use and concomitant cigarette smoking in heroin addicts make cause-effect relationships difficult to assess. In general, the history of inhalative heroin consumption should be considered in patients presenting with any unkown pulmonary disease with severe bronchospasms as may happen in a severe asthma exacerbation.

Enhanced Delivery and Effects of Acid Sphingomyelinase by ICAM-1-Targeted Nanocarriers in Type B Niemann-Pick Disease Mice

Acid sphingomyelinase deficiency in type B Niemann-Pick disease leads to lysosomal sphingomyelin storage, principally affecting lungs, liver, and spleen. Infused recombinant enzyme is beneficial, yet its delivery to the lungs is limited and requires higher dosing than liver and spleen, leading to potentially adverse reactions. Previous studies showed increased enzyme pulmonary uptake by nanocarriers targeted to ICAM-1, a protein overexpressed during inflammation. Here, using polystyrene and poly(lactic-co-glycolic acid) nanocarriers, we optimized lung delivery by varying enzyme dose and nanocarrier concentration, verified endocytosis and lysosomal trafficking in vivo, and evaluated delivered activity and effects. Raising the enzyme load of nanocarriers progressively increased absolute enzyme delivery to all lung, liver, and spleen, over the naked enzyme. Varying nanocarrier concentration inversely impacted lung versus liver and spleen uptake. Mouse intravital and postmortem examination verified endocytosis, transcytosis, and lysosomal trafficking using nanocarriers. Compared to naked enzyme, nanocarriers increased enzyme activity in organs and reduced lung sphingomyelin storage and macrophage infiltration. Although old mice with advanced disease showed reactivity (pulmonary leukocyte infiltration) to injections, including buffer without carriers, antibody, or enzyme, younger mice with mild disease did not. We conclude that anti-ICAM nanocarriers may result in effective lung enzyme therapy using low enzyme doses.