Histopathological changes in zebrafish exposed to sublethal concentrations of 89 nm silver nanoparticles for application in environmental diagnostics

Abstract

The use of biomarkers as indicators of environmental contamination has been shown to be an excellent indicator of changes in biota. Histopathological lesions are commonly used in biomonitoring studies as they provide information regarding both acute and chronic exposure. The use of nanoparticle materials has been widespread in recent years. However, not much is known about their ecological effects on the natural environment. Thus, the aim of this study was to assess the sublethal effects of silver nanoparticles (AgNP) with mean diameters of 89?nm in the zebrafish Danio rerio by the determination of the LC₅₀; 48?h and histopathological assays in gills. The obtained LC₅₀; 48?h was 8.18 µgL^?1. The histopathological gill assessment showed primary responses indicative of acute damage as aneurysms (32.76%), hyperplasia (20.69%) and partial (30.17%) and total lamellar fusion (6.9%) of secondary lamellae. No deposition of AgNP was observed in any tested sample gills, suggesting other organs target to absorption and detoxification. In fact, the AgNP causes sublethal damage in the gills of zebrafish but is not able to accumulate in this tissue. Finally, the data shown in this study contribute to the construction of a database on the AgNP exposure in aquatic organisms.     

Antibiofilm action of a toluidine blue O-silver nanoparticle conjugate on Streptococcus mutans: a mechanism of type I photodynamic therapy

The objective of this study was to evaluate the anti-biofilm efficacy of photodynamic therapy by conjugating a photosensitizer (TBO) with silver nanoparticles (AgNP). Streptococcus mutans was exposed to laser light (630 nm) for 70 s (9.1 J cm^?2) in the presence of a toluidine blue O–silver nanoparticle conjugate (TBO–AgNP). The results showed a reduction in the viability of bacterial cells by 4 log₁₀. The crystal violet assay, confocal laser scanning microscopy and scanning electron microscopy revealed that the TBO–AgNP conjugates inhibited biofilm formation, increased the uptake of propidium iodide and leakage of the cellular constituents, respectively. Fluorescence spectroscopic studies confirmed the generation of OH^? as a major reactive oxygen species, indicating type I phototoxicity. Both the conjugates down-regulated the expression of biofilm related genes compared to TBO alone. Hence TBO–AgNP conjugates were found to be more phototoxic against S. mutans biofilm than TBO alone.     

Prolonged inhibitory effects against planktonic growth,adherence, and biofilm formation of pathogens causing ventilator-associated pneumonia using a novel polyamide/silver nanoparticle composite-coated endotracheal tube

Abstract

Microbial cells can rapidly form biofilm on endotracheal tubes (ETT) causing ventilator-associated pneumonia, a serious complication in patients receiving mechanical ventilation. A novel polyamide with a good balance of hydrophilic/hydrophobic moieties was used for the embedment of green-reduction silver nanoparticles (AgNPs) for the composite-coated ETT. The films were conformal with a thickness of ～ 17?±?3?µm accommodating high loading of 60?±?35?nm spherical-shaped AgNPs. The coated ETT resulted in a significant difference in reducing both planktonic growth and microbial adhesion of single and mixed-species cultures, compared with uncoated ETT (p?<?0.05). A time-kill assay demonstrated rapid bactericidal effects of the coating on bacterial growth and cell adhesion to ETT surface. Biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus, commonly encountered pathogens, was inhibited by > 96% after incubation for 72?h. Polyamide/AgNP composite-coated ETT provided a broad-spectrum activity against both Gram-positive and Gram-negative bacteria as well as Candida albicans and prolonged antimicrobial activity.     

A comparative study on the antioxidant effects of hesperidin and ellagic acid against skeletal muscle ischemia/reperfusion injury

Abstract

The antioxidant effects of ellagic acid (EA) and hesperidin (HES) against skeletal muscle ischemia/reperfusion injury (I/R) were performed. Hindlimb ischemia has been induced by tourniquet occlusion for 2?h on left hindlimb. At the end of ischemia, the tourniquate has been removed and initiated reperfusion for 2?h. EA (100?mg/kg) has been applied orally before ischemia/reperfusion in the EA?+?I/R group. HES (100?mg/kg) has been given orally in the HES?+?I/R group. The left gastrocnemius muscle has been harvested and stored immediately at??80?°C until assessed for the levels of MDA and antioxidant enzymes activities. MDA level has statistically increased in I/R group (p?<?0.05) compared to other groups. The muscle tissue antioxidant enzymes activities were lower than the other groups in the I/R group (p?<?0.05). EA and HES treatments significantly reversed the damage level in I/R, also activity of tissue SOD increased in the EA?+?I/R and HES?+?I/R groups.     

The antioxidant effects of pomegranate extract on local and remote organs in a mesenteric ischemia and reperfusion model

Objectives: We investigated whether pomegranate extract plays a protective antioxidant role against mesenteric ischemia–reperfusion injury (IR), which can lead to a systemic response and damage distant organs, such as the lung, liver, and kidney.

Methods: Forty female Wistar–Albino rats were separated into four groups: laparotomy, laparotomy?+?PG, mesenteric IR, and mesenteric IR and pomegranate (IR?+?PG). In the laparotomy?+?PG and IR?+?PG groups, pomegranate (225?mg/kg) was given by oral gavage at the beginning of the study. Ischemia was induced for 30 minutes, and reperfusion was subsequently allowed for 60 minutes in the IR and IR?+?PG groups. The malondialdehyde (MDA) and total antioxidant activity (AOA) levels were evaluated in blood samples. Additionally, all tissues were removed for the measurement of AOA and total oxidant status as well as for subsequent histopathological evaluation. The oxidative stress index was calculated.

Results: Histopathological changes in all organs were significantly higher in the IR group and significantly lower in the IR?+?PG group vs. the other groups. Serum MDA levels were significantly lower in the IR?+?PG group than in the IR group. No significant difference was found in AOA levels of the groups.

Discussion: These data may explain the positive protective effects of pomegranate based on the histopathologic findings in ischemic conditions in an intestinal IR injury model.     

Synthesis and characterization of silver nanoparticles using Cynodon dactylon leaves and assessment of their antibacterial activity

Many methods of synthesizing silver nanoparticles (Ag-NPs) by reducing Ag⁺ ions using aqueous/organic extracts of various plants have been reported in the past, but the methods are rather slow. In this investigation, silver nanoparticles were quickly synthesized from aqueous silver nitrate through a simple method using leaf extract of a plant—Cynodon dactylon which served as reducing agent, while sunlight acted as a catalyst. The formation of Ag-NPs was indicated by gradual change in colour and pH and confirmed by ultraviolet–visible spectroscopy. The Ag-NPs showed a surface plasmon resonance at 451 nm. Based on the decrease in pH, a possible mechanism of the synthesis of Ag-NPs involving hydroxyl (OH^?) ions of polyphenols of the leaf extract is postulated. Ag-NPs having (111) and (200) crystal lattices were confirmed by X-ray diffraction. Scanning electron microscopy revealed the spherical nature of the Ag-NPs, while transmission electron microscopy showed that the nanoparticles were polydispersed with a size range of 8–10 nm. The synthesized Ag-NPs also demonstrated their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhimurium.     

Biochemical alterations induced by nickel oxide nanoparticles in female Wistar albino rats after acute oral exposure

Context: Nickel oxide (NiO) nanoparticles (NPs) with appropriate surface chemistry have been widely used for their potential new applications in biomedical industry. Increased usage of these NPs enhances the chance of exposure of personnel involved in the work place.

Objective: This study was designed to assess the ability of NiO NPs to cause biochemical alterations post-acute oral exposure in female Wistar rats.

Materials and methods: Rats were administered with 125, 250, and 500?mg/kg doses of NiO NPs for haematological, biochemical, and histopathological studies. Biodistribution patterns of NiO NPs in female Wistar rats were also monitored.

Results: NiO NPs caused significant (p?Conclusions: This study revealed that exposure to nanosized NiO particles at acute doses may cause adverse changes in animal biochemical profiles. Further, the in vivo studies on toxicity evaluation help in biomonitoring of the potential contaminants.     

Combined application of arbuscular mycorrhizal fungi and steel slag improves plant growth and reduces Cd,Pb accumulation in Zea mays

Abstract

Little attention has been paid to the combined use of arbuscular mycorrhizal fungus (AMF) and steel slag (SS) for ameliorating heavy metal polluted soils. A greenhouse pot experiment was conducted to study the effects of SS and AMF?Funneliformis mosseae (Fm), Glomus versiforme (Gv) and Rhizophagus intraradices (Ri) on plant growth and Cd, Pb uptake by maize grown in soils added with 5?mg Cd kg^?1 and 300?mg Pb kg^?1 soil. The combined usage of AMF and SS (AMF?+?SS) promoted maize growth, and Gv?+?SS had the most obvious effect. Meanwhile, single SS addition and AMF?+?SS decreased Cd, Pb concentrations in maize, and the greater reductions were found in combined utilization, and the lowest Cd, Pb concentrations of maize appeared in Gv?+?SS. Single SS amendment and AMF?+?SS enhanced soil pH and decreased soil diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Pb concentrations. Furthermore, alone and combined usage of AMF and SS increased contents of soil total glomalin. Our research indicated a synergistic effect between AMF and SS on enhancing plant growth and reducing Cd, Pb accumulation in maize, and Gv?+?SS exerted the most pronounced effect. This work suggests that AMF inoculation in combination with SS addition may be a potential method for not only phytostabilization of Pb-Cd-contaminated soil but maize safety production.     

Development and in vitro/in vivo evaluation of artemether and lumefantrine co-loaded nanoliposomes for parenteral delivery

Combination therapy of artemether (ART) and lumefantrine (LUM) is well-established for the treatment of uncomplicated malaria worldwide. Nanoliposomes (NLs) encapsulating both drugs were prepared and freeze-dried. The lyophilized nanoliposomes exhibited high entrapment efficiency of artemether (66.18%), relatively low entrapment efficiency of lumefantrine (53.46%), low average size diameter (125.3?nm) and found to be stable at 4?°C for 60 days without significant change in mean particle diameter and drug entrapment efficiencies. In vitro drug release study has shown initial burst effect and then sustained release pattern over a time period of 30?h. In vivo toxicity study was examined by liver and kidney function test as well as histopathological examination. Nanoliposomes showed lower hemolytic potential (～10%) compared to all the components when studied individually. There was no significant change (p?>?0.05) in biochemical parametes between control and treated group of animals. Pharmacokinetic data of ART?+?LUM NLs showed higher the area under the plasma concentration–time curve (AUC) values and prolonged residence time of drug in the blood circulation compared with ART?+?LUM solution. The tissue distribution demonstrated high uptake of ART?+?LUM-NLs in RES organs particularly in liver and spleen. Biocompatibility was confirmed by hepato- and nephrotoxicity analysis showed no sign of fibrosis, fatty infiltration, centrilobular necrosis and lymphocyte infiltration confirmed the suitability of developed formulation for treatment of malaria.     

H2AFZ,RNF4 and NR4A1 loci are associated with boar semen quality by population association studies

Abstract

Spermatogenesis is a complex process regulated by many genes. In this study, H2AFZ, RNF4 and NR4A1 genes were selected as candidate genes for boar semen quality traits based on their functions during spermatogenesis, and the associations of three loci (H2AFZ c.192?+?210–192?+?213delCGAT, RNF4 c.374?+?358 T?>?C and NR4A1 c.956?+?796 A?>?G) with sperm quality traits were analyzed in Duroc (n?=?185), Large White (n?=?87) and Landrace (n?=?49) pig populations. The results showed H2AFZ c.192?+?210–192?+?213delCGAT AA boars produced 1.52% lower abnormal sperm rate (ASR) than AB boars in Landrace pigs (p?<?0.05); RNF4 c.374?+?358?TC boars produced 0.31?×?10⁸/ml higher sperm concentration (SCON) than CC boars (p?<?0.05) in Large White pigs; NR4A1 c.956?+?796 A?>?G was associated with ASR in Duroc and Large White pigs and was associated with sperm motility (MOT) in Large White and Landrace pigs. This study indicated the H2AFZ, RNF4 and NR4A1 loci were the potential molecular markers for improving the semen quality traits in boars.     

Antidepressant effect and neural mechanism of Acer tegmentosum in repeated stress–induced ovariectomized female rats

ABSTRACT

Acer tegmentosum (ATM) has antioxidant and anti-adipogenic activity. However, few studies have investigated the pharmacological activity or mechanism of ATM as an antidepressant agent. We assessed the antidepressant effect of ATM in modulating menopausal depressive symptoms and its mechanisms in ovariectomized (OVX) and repeatedly stressed (RS) female rats. The female rats were randomly divided into four groups: (1) naïve normal (normal) group, (2) OVX?+?repeated stress?+?saline-treated (control) group, (3) OVX?+?repeated stress?+?ATM (100?mg?kg^?1)-treated (ATM100) group and (4) OVX?+?repeated stress?+?ATM (400?mg?kg^?1)-treated (ATM400) group. We performed a battery of tests, such as the forced swimming test (FST), the sucrose intake test, and social exploration. After behavior testing, serum corticosterone levels were examined, followed by immunohistochemical determination of c-Fos, tyrosine hydroxylase (TH), and interleukin-1 beta (IL-1β) expression in the brain. ATM administration was associated with significantly decreased immobility time in the FST. Also, the control group tended to have decreased sucrose intake and social exploration compared with the normal group. However, ATM treatment was associated with markedly increased sucrose intake and active social exploration. In the paraventricular nucleus, c-Fos and IL-1β expression were significantly decreased in the ATM400 group compared with the control group. Compared with the control group, high-dose ATM administration was also associated with markedly decreased expression of TH-immunoreactive neurons in the locus coeruleus. The study findings demonstrated that ATM treatment effectively decreased behavioral and pathophysiological depression-like responses.     

Comparison of sensory tests and neuronal quantity of peripheral nerves between streptozotocin (STZ)-induced diabetic rats and paclitaxel (PAC)-treated rats

Although diabetic peripheral neuropathy (DPN) and chemotherapy-induced peripheral neuropathy (CIPN) are different disease entities, they share similar neuropathic symptoms that impede quality of life for these patients. Despite having very similar downstream effects, there have been no direct comparisons between DPN and CIPN with respect to symptom severity and therapeutic responses. We compared peripheral nerve damage due to hyperglycemia with that caused by paclitaxel (PAC) treatment as represented by biochemical parameters, diverse sensory tests, and immunohistochemistry of cutaneous and sciatic nerves. The therapeutic effects of alpha-lipoic acid and DA-9801 were also compared in the two models. Animals were divided into seven groups (n?=?7–10) as follows: normal, diabetes (DM), DM?+?alpha-lipoic acid 100?mg/kg (ALA), DM?+?DA-9801 (100?mg/kg), paclitaxel-treated rat (PAC), PAC?+?ALA (100?mg/kg), and PAC?+?DA-9801 (100?mg/kg). The sensory thresholds of animals to mechanical, heat, and pressure stimuli were altered by both hyperglycemia and PAC when compared with controls, and the responses to sensory tests were different between both groups. There were no significant differences in the biochemical markers of blood glutathione between DM and PAC groups (p?>?.05). Quantitative comparisons of peripheral nerves by intraepidermal nerve fiber density (IENFD) analysis indicated that the DM and PAC groups were similar (6.18?±?1.03 vs. 5.01?±?2.57). IENFD was significantly improved after ALA and DA-9801 treatment in diabetic animals (7.6?±?1.28, 7.7?±?1.28, respectively, p?p?>?.05). Sciatic nerves were less damaged in the PAC-treated groups compared with the DM groups with respect to axonal diameter and area (8.60?±?1.14?μm vs. 6.66?±?1.07?μm, and 59.04?±?15.16?μm² vs. 35.71?±?11.2?μm², respectively, p?相似文献   

Edge activators and a polycationic polymer enhance the formulation of porous voriconazole nanoagglomerate for the use as a dry powder inhaler

Purpose: Voriconazole has both low aqueous solubility and stability. We hypothesize that designing voriconazole in the form of a nano powder inhaler at a geometric diameter within 1–5?μm will enhance its stability and solubility. Therefore, we prepared nanoagglomerates of voriconazole which will collapse in the lungs to reform the nanoparticles.

Method: The nanoparticles were formulated using both stearic acid and sodium deoxycholate as edge activators. Osmogenic polycation polyethyleneimine (PEI) was used to form agglomerates of controllable size.

Results: Voriconazole nanoparticles and agglomerates showed a significant higher cumulative drug release than the pure powder (p?R^2?=^?0.95. Small-sized particles were formed (353?nm), while their zeta potential was ?30.7?mV. The agglomerates were 2.7?μm in size and their zeta potential was ?20.9?mV. The formation of porous agglomerates was confirmed using a transmission electron microscope. Cascade impactor was used to evaluate the aerodynamic properties of the nanoparticles and the agglomerates. The aerodynamic characterization of the nanoparticles and the agglomerates resulted in a significant smaller mass median aerodynamic diameter (MMAD) (p?p?p?p?Conclusion: The results suggest that using the combination of edge activators and diluted polycationic polymer solution provides porous voriconazole nanoagglomerates in a respirable range, which is proved successful in enhancing both the deposition and the dissolution of water insoluble-drugs in the lung.     

Ecotoxicological impacts of exposure to copper oxide nanoparticles on the gill of the Swan mussel,Anodonta cygnea (Linnaeus, 1758)

This study was conducted to investigate the ecotoxicological effects of exposure to copper oxide nanoparticles (CuO NPs) on the gill of the swan mussel Anodonta cygnea using several approaches including qualitative and quantitative histopathology, ultra-morphology (scanning electron microscopy [SEM]) and measures of clearance rate (CR) and bioaccumulation of CuO NPs. Histological alterations in mussels exposed to 0.25 (T1), 2.5 (T2) and 25.0?µg L^?1 (T3) CuO NPs for 12 days include changes in the length and form of gill lamellae, changes in inter-lamellar spaces, epithelial hyperplasia, atrophy and tissue rupture. Ultra-morphological changes following CuO NP exposure included epithelial hyperplasia and hypertrophy, epithelial lifting, tissue rupture (water channel fusion) and extensive necrosis of the gill surfaces. I_Gill (gill damage severity) index values for both histopathological and ultra-morphological data were significantly (P?0.05) higher in T3. The CR of mussels was significantly (P??1 g^?1 dry weight]) in comparison to controls (CR?=?108?±?47.14 [L min^?1 g^?1 dry weight]). CuO NPs accumulated in exposed mussels at all exposure concentrations until day 4, but there was no further change in accumulation levels by the end of the exposure period. The accumulated content of CuO NPs was significantly (P??1 exposure concentration. Based on these results, significant accumulation of CuO NPs in the gills of swan mussel could affect histological and ultra-structural characteristics of this organ and consequently have deleterious impacts on its filtration activity.     

Assessment of Waterborne Amine-Coated Silver Nanoparticle (Ag-NP)-Induced Toxicity in <Emphasis Type="Italic">Labeo rohita</Emphasis> by Histological and Hematological Profiles

Silver nanoparticles (Ag-NPs) have wide applications in the medical field; however, the toxicological effects are still poorly studied. The study was aimed to determine the effects of 15.78 nm spherical and amine-coated Ag-NPs on hematology and histology of gills and liver tissues in 28 days treated Labeo rohita (L. rohita). It was found that Ag-NPs induced alterations in the hematological parameters in a dose dependent manner. The Ag-NPs also induced histological alterations in a dose-dependent manner. In gill tissues, it induced fusion of secondary lamellae, separation of gill epithelium, fusion and necrosis of lamellar cells, hyperplasia, deformed cartilaginous skeleton, separation and lifting of epithelium, and curling of lamellae in a dose dependent manner. In the liver, Ag-NPs produced abnormalities in hepatic tissues by reducing the size of hepatocytes and nuclei, and stimulated the production of necrotic and apoptotic bodies. It was concluded that Ag-NPs are toxic to aquatic organisms and induce hematotoxicity and histopathological conditions in exposed fish.     

Assay-dependent effect of silver nanoparticles to <Emphasis Type="Italic">Escherichia coli</Emphasis> and <Emphasis Type="Italic">Bacillus subtilis</Emphasis>

We assess the microbial assay-dependent effect of AgNP on gram-negative Escherichia coli and gram-positive Bacillus subtilis. The experiment was conducted via three different assays: a growth inhibition assay, a colony forming unit assay, and a liquid-to-plate assay. AgNP were exposed either as liquid suspensions or in an agar state. Bacterial sensitivity to AgNP was found to be dependent on the microbial assay employed. E. coli was more sensitive than B. subtilis in the growth inhibition and CFU assays, but B. subtilis was more vulnerable than E. coli in the liquid-to-plate assay, ostensibly owing to the food stress mechanisms of B. subtilis in exposure medium. The dissolution of silver from AgNP could not explain the observed toxicity of AgNP. We detected clear evidence of AgNP uptake by cells. The results of this study showed that the microbial toxicity of AgNP and the effects of dissolved silver ions were influenced profoundly by the microbial test method employed.     

Characterisation of silver nanoparticles synthesised by Bacillus thuringiensis as a nanobiopesticide for insect pest control

Nanotechnology has become one of the most promising new approaches for pest control in recent years. In this research, biocompatible silver nanoparticles (Btk-AgNPs) were synthesised by using the entomopathogenic bacterium, Bacillus thuringiensis kurstaki (Btk) as a low-cost and eco-friendly production system. The AgNP samples exhibited a brownish-yellow colour that is characteristic for silver nanoparticles synthesis. Btk-synthesised AgNPs were produced using both the supernatant and pellet of Bt culture at various concentrations and AgNP particles were characterised by UV-Vis spectrophotometer and Dynamic Light Scattering (DLS). The variation of hydrodynamic diameter (D_h) and UV-Vis spectra of silver particles produced by various concentration of culture showed that production of AgNPs was maximised when using 20% for either supernatant or pellet treatments of Bt of culture and the size of particles was around 85?nm for both. The insecticidal efficacy of Btk-synthesised AgNPs against larvae of the cabbage looper, Trichoplusia ni (Hübner) and black cutworm, Agrotis ipsilon (Hufnagel) was tested. Results demonstrated that the treatments of either Btk-synthesised AgNP(s) made with Bt supernatant or Btk-synthesised AgNP(p) using Bt pellet were found to be significantly more virulent toward larvae of T. ni than to A. ipsilon.     

In vitro investigation of hypoglycemic and oxidative stress properties of fava bean (Vicia faba L.) seed extract in Saccharomyces cerevisiae 2376

Abstract

Imbalance of free radicals over antioxidants in human body may result in oxidative damage to biomolecules (lipids, proteins, DNA) that causes severe chronic diseases. The aim of this proposed research was to examine the hypoglycemic and oxidative stress potential of fava bean (Vicia faba L.) seed extract. Acetone extract showed a significant effect on glucose uptake rate (77.28?±?2.42%) in yeast cells at 25?mM glucose concentration. Minimum glucose uptake rate was found to be 52.36?±?2.06% % by chloroform seed extract. Atomic force microscopy revealed that 3% hydrogen peroxide concentration results in roughness was found to be maximum (441?±?6.7?nm) and along with extract treatment showed a significant reduction in roughness (251?±?6.2?nm). Propidium iodide and DAPI staining showed apoptotic ratio as 0.40 (40?±?1.18%,) and 0.42 (42?±?1.16%) in hydrogen peroxide treated cell only as compared to other treatments. MTT assay showed that acetone extract had maximum survival rate (82.067%) and least survival rate was found in chloroform extract (70.48%). Hypoglycaemic potential and oxidative stress might be polyphenols (phenolics, flavonoids) present in seed extract or synergistic effect.     

Predicting bone turnover following tobacco exposure using bone alkaline phosphatase and N-telopeptide biomarkers and possible variability and effect modification of these markers by race/ethnicity

Abstract

Introduction: This study investigated the systemic response of serum bone alkaline phosphatase (SBAP) and urinary N-telopeptide (UNTX) to tobacco exposure and environmental tobacco smoke (ETS) and the possible effect modification (and variability) of this response by racial/ethnic origin.

Methods: Data (n?=?5411) were obtained from the National Health and Nutrition Examination Survey, with data analysis done on adults aged ≥ 20?years. Outcome variables were SBAP and UNTX. Independent variable was tobacco exposure measured using serum cotinine levels and adjusted for covariates. Generalized linear models were used to explore associations.

Results: A percentage increase in log transformed serum cotinine was associated with a 0.005 percentage increase in log transformed SBAP (CI: 0.002, 0.008) and 0.02 percentage increase in log transformed UNTX (CI: ?0.01, 0.04) with interaction between cotinine and race/ethnicity (p?=?0.01). Stratifying by race/ethnicity, tobacco exposure was associated with significant decreases in UNTX among non-Hispanic Whites – 0.008(?0.014, ?0.002) and Mexican Americans ?0.014 (?0.025, ?0.002) only. Categories of serum cotinine were associated with a monotonic increase in SBAP (p for trend <0.001) and monotonic non-linear decrease in UNTX (p for trend?>?0.05).

Conclusions: Tobacco and environmental tobacco exposure are associated with SBAP and increased bone formation. The response of UNTX to these exposures is modified by race/ethnicity with non-Hispanic Whites and Mexican-Americans less sensitive to the resorptive effects of tobacco exposure on bone.