Pulmonary inflammatory responses and retention dynamics of cellulose nanofibrils.

Cellulose nanofibrils (CNFs) are advanced biomaterials valued for their strength, lightweight nature, and low thermal expansion, making them suitable for diverse industrial applications. However, their potential inhalation risks necessitate thorough safety evaluations. This study investigates the pulmonary inflammatory effects and retention of CNFs following intratracheal instillation in rats.

Effects of advanced nanomaterials on the respiratory system of a murine COPD model.

This study assessed the effects of cellulose nanofibrils (CNFs) and multi-walled carbon nanotubes (MWCNTs) on lung inflammation in a cigarette smoke-induced chronic obstructive pulmonary disease (COPD) mouse model. Prior to instillation, COPD model mice displayed distinctive cellular compositions and elevated cytokine levels in bronchoalveolar lavage fluid (BALF). After intratracheal instillation of 80 μg CNFs, no significant histopathological changes, BALF composition alterations, or cytokine level shifts were observed on day 28.

Contaminant microorganisms in the evaluation of cellular responses of cellulose nanofibers and their microbial inactivation using gamma irradiation.

Cellulose nanofibers (CNFs) are fibrous nanomaterials produced from plants. Since some nanomaterials are toxic, toxicity evaluation, including examinations using cultured cells, is essential for the effective use of CNFs. On the other hand, microorganisms in the environment can contaminate CNF suspensions.

Genotoxicity assessment of cellulose nanofibrils using a standard battery of and assays.

Cellulose nanofibrils (CNFs) are identified as novel nanomaterials with many potential applications. Since CNFs are fibrous manufactured nanomaterials, their potential carcinogenic effects and mesothelial toxicity raise some concerns. In this study, we conducted a standard battery of and assays to evaluate the genotoxicity of two CNF types using different manufacturing methods and physicochemical properties.

Screening of preservatives and evaluation of sterilized cellulose nanofibers for toxicity studies.

Objectives: The aim of this study is to establish a sterilization method for cellulose nanofibers (CNFs) dispersions that uses multiple preservatives with different hydrophilicities without affecting the physical and chemical properties of CNFs, and to provide useful information for sample preparation in future toxicity study of CNFs.

Methods: Various preservatives were added to the phosphorylated CNF dispersions, endotoxin level and the numbers of bacteria and fungi in the CNF dispersion were analyzed. The pH values and viscosity of sterilized CNF dispersions were compared with those of control and autoclaved CNF dispersions.

Cytotoxicity profiles of multi-walled carbon nanotubes with different physico-chemical properties.

Multi-walled carbon nanotubes (MWCNTs) have industrial applications in the nanotechnology field. The physico-chemical properties of MWCNTs vary greatly depending on MWCNT manufacture and application. It has been pointed out that their needle shape and high durability are important factors that determine the biopersistence of fibers and can lead to inhalation toxicity or cytotoxicity.

Assessment of cytotoxicity and mutagenicity of exfoliated graphene.

Graphene and related materials (GRMs) have unique optical and thermal characteristics and are expected to be adopted for industrial applications. However, there are concerns with respect to their safety to human health. To conduct cytotoxicity and mutagenicity assessments, exfoliated graphene (EGr) dispersed in Tween-20® was diluted in cell culture medium.

Risk Factors for In-hospital Mortality and Reamputation Following Lower Limb Amputation.

Objective: Studies on the outcomes of lower limb amputation have been limited by the use of selected study populations and small sample sizes. Although reamputation is an important outcome following lower limb amputation, the risk factors for reamputation remain to be elucidated. The present study was performed to identify risk factors for in-hospital death and reamputation following lower limb amputation.

Time to initiation or duration of S-1 adjuvant chemotherapy; which really impacts on survival in stage II and III gastric cancer?

Background: Surgical resection with S-1 adjuvant chemotherapy (AC) is the standard of care for stage II-III gastric cancer (GC). However, it is unclear if time to initiation and duration of S-1 AC impact on survival.

Methods: A multi-institutional GC database identified 498 patients who were treated with S-1 AC after D2 or more extended radical surgery for stage II-III gastric cancer.

Basic study of intratracheal instillation study of nanomaterials for the estimation of the hazards of nanomaterials.

In order to examine the usefulness of intratracheal instillation of nanoparticles for the screening of the harmful effects of nanoparticles, we performed intratracheal instillation studies of nanomaterials on rats using different delivery devices and postures as a basic study. Multiwall carbon nanotubes (MWCNTs) with a geometric mean length and secondary diameter of 2.16 μm and 752 nm, respectively, were used as the nanomaterials.

Pulmonary and pleural inflammation after intratracheal instillation of short single-walled and multi-walled carbon nanotubes.

Relationships between the physical properties of carbon nanotubes (CNTs) and their toxicities have been studied. However, little research has been conducted to investigate the pulmonary and pleural inflammation caused by short-fiber single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs). This study was performed to characterize differences in rat pulmonary and pleural inflammation caused by intratracheal instillation with doses of 0.

Risk Assessment of the Carbon Nanotube Group.

This study assessed the health risks via inhalation and derived the occupational exposure limit (OEL) for the carbon nanotube (CNT) group rather than individual CNT material. We devised two methods: the integration of the intratracheal instillation (IT) data with the inhalation (IH) data, and the "biaxial approach." A four-week IH test and IT test were performed in rats exposed to representative materials to obtain the no observed adverse effect level, based on which the OEL was derived.

Size effects of single-walled carbon nanotubes on in vivo and in vitro pulmonary toxicity.

To elucidate the effect of size on the pulmonary toxicity of single-wall carbon nanotubes (SWCNTs), we prepared two types of dispersed SWCNTs, namely relatively thin bundles with short linear shapes (CNT-1) and thick bundles with long linear shapes (CNT-2), and conducted rat intratracheal instillation tests and in vitro cell-based assays using NR8383 rat alveolar macrophages. Total protein levels, MIP-1α expression, cell counts in BALF, and histopathological examinations revealed that CNT-1 caused pulmonary inflammation and slower recovery and that CNT-2 elicited acute lung inflammation shortly after their instillation. Comprehensive gene expression analysis confirmed that CNT-1-induced genes were strongly associated with inflammatory responses, cell proliferation, and immune system processes at 7 or 30 d post-instillation.

Ascorbic acid attenuates acute pulmonary oxidative stress and inflammation caused by zinc oxide nanoparticles.

Objectives: It is known that inhalation of zinc oxide nanoparticles (ZnO NPs) induces acute pulmonary dysfunction, including oxidative stress, inflammation, and injury, but there are no reports on how to prevent these adverse effects. We have previously reported that the pulmonary symptoms caused by ZnO NPs were associated with oxidative stress; in the present study, we therefore investigated the use of ascorbic acid (AA), which is known as vitamin C, to prevent these toxic effects.

Methods: A ZnO NP dispersion was introduced into rat lungs by intratracheal injection, and thereafter a 1% aqueous AA solution was given as drinking water.

The induction of lipid peroxidation during the acute oxidative stress response induced by intratracheal instillation of fine crystalline silica particles in rats.

Crystalline silica (SiO) is an important material for industry but is considered potentially carcinogenic. Inhalation of a crystalline SiO aerosol may contribute to serious lung diseases. Crystalline SiO particles are commonly used as a positive control in toxicity assays of particulate materials (e.

Cellular effects of industrial metal nanoparticles and hydrophilic carbon black dispersion.

The effects of five types of metal nanoparticles, gold (Au), silver (Ag), platinum (Pt), Au-polyvinylpyrrolidone (PVP) colloid, and Pt-PVP colloid, and two types of hydrophilic carbon black on cell behavior were examined. Stable nanoparticle dispersions were prepared and applied to the culture medium of human keratinocyte (HaCaT) and human lung carcinoma (A549) cells for 6 and 24 hr. Then, the mitochondrial activity (MTT assay) and the induction of cellular oxidative stress were examined.

Intratracheal instillation of single-wall carbon nanotubes in the rat lung induces time-dependent changes in gene expression.

The use of carbon nanotubes in the industry has grown; however, little is known about their toxicological mechanism of action. Single-wall carbon nanotube (SWCNT) suspensions were administered by single intratracheal instillation in rats. Persistence of alveolar macrophage-containing granuloma was observed around the sites of SWCNT aggregation at 90 days post-instillation in 0.

Evaluation of particles released from single-wall carbon nanotube/polymer composites with or without thermal aging by an accelerated abrasion test.

To provide data required for assessing the environmental health and safety risks of nanocomposites, abrasion-induced particle release from single-wall carbon nanotube (SWCNT)/polymer composites with or without thermal aging were evaluated by a shot blast system. First, overall composite weight loss (i.e.

Evaluation of cellular influences caused by calcium carbonate nanoparticles.

The cellular effects of calcium carbonate (CaCO₃) nanoparticles were evaluated. Three kinds of CaCO₃ nanoparticles were employed in our examinations. One of the types of CaCO₃ nanoparticles was highly soluble.

Evaluation of cellular effects of silicon dioxide nanoparticles.

Silica nanoparticles (nSiO2s) are an important type of manufactured nanoparticles. Although there are some reports about the cytotoxicity of nSiO2, the association between physical and chemical properties of nSiO2s and their cellular effects is still unclear. In this study, we examined the correlation between the physiochemical properties and cellular effects of three kinds of amorphous nSiO2s; sub-micro-scale amorphous SiO2, and micro-scale amorphous and crystalline SiO2 particles.

Analysis of pulmonary surfactant in rat lungs after intratracheal instillation of short and long multi-walled carbon nanotubes.

Multi-walled carbon nanotubes (MWCNTs) are interesting new materials, but there is some concern about their harmfulness due to their fibrous nature. To determine the difference in the biological effects of MWCMTs by fiber length, we prepared two MWCNT samples from one bulk sample. One consisted of cut up short fibers (Short; average length=0.

In vitro evaluation of cellular influences induced by stable fullerene C₇₀ medium dispersion: induction of cellular oxidative stress.

Fullerene is one of the nanocarbons that is expected to have applications to life science, such as nanomedicines. An understanding of the cellular influences of fullerene is essential for its application to life science. Although C₆₀ and C₇₀ are both known as major fullerenes, most previous reports about the cellular influences of fullerene are about C₆₀.

Physical properties of single-wall carbon nanotubes in cell culture and their dispersal due to alveolar epithelial cell response.

Concern over the influence of carbon nanotubes (CNTs) on human health has arisen due to advances; however, little is known about the potential toxicity of CNTs. In this study, impurity-free single-wall carbon nanotubes (SWCNTs), with different physical properties in cell culture medium, were prepared by a novel dispersion procedure. SWCNTs with small bundles (short linear shape) and SWCNTs with large bundles (long linear shape) did not cause a significant inhibition of cell proliferation, induction of apoptosis or arrest of cell cycle progression in A549 alveolar epithelial cells.

Dispersant affects the cellular influences of single-wall carbon nanotube: the role of CNT as carrier of dispersants.

The application of carbon nanotube (CNT) as a functional material to engineering and life sciences is advanced. In order to evaluate the cytotoxicity of CNT in vitro, some chemical and biological reagents are used for dispersants. In the present study, the cellular influences of six kinds of chemical or biological reagents used as dispersants were examined.