Prevalence and predictors of medication for opioid use disorder among reproductive-aged women.

Background: Women of reproductive age would benefit from treatment of opioid use disorder (OUD) prior to pregnancy to improve maternal and infant outcomes. In this study, we aimed to identify the prevalence of medication for OUD (MOUD) and characterize correlates of MOUD receipt among 12-49-year-old women with OUD seeking treatment in publicly funded substance use disorder treatment programs at the time of their first treatment episode. Methods: This cross-sectional study explores the demographic and clinical characteristics of women of reproductive age with OUD receiving publicly funded substance use treatment services. We used data from the concatenated 2015-2021 Treatment Episode Data Set-Admissions (TEDS-A), which documents demographic and clinical characteristics of patient admissions to publicly funded substance use treatment services in the United States. Results: In the sample of females aged 12-49 with no prior treatment admissions and primary OUD (n=325,512), 40.53% received MOUD (n=131,930), including 39.40% of non-pregnant women (n=115,315) and 52.79% of pregnant women (n=8423). Pregnant women had significantly higher odds of receiving MOUD (aOR = 2.42, 95%CI: 2.30, 2.54) compared to non-pregnant women. Non-white race, treatment setting, and treatment self-referral were also associated with higher levels of MOUD. Conclusions: We identified a significant unmet need among both pregnant and non-pregnant women with OUD seeking care in publicly funded treatment clinics. While women who are pregnant are significantly more likely to receive evidence-based treatment with MOUD, still 47.21% of pregnant women did not receive MOUD. All reproductive-aged women with OUD should be offered evidence-based treatment options, including MOUD.

Sexual and reproductive health behaviors of women with criminal legal involvement and substance use disorders: A life course perspective.

OBJECTIVE: Early exposure to drug use and sexual abuse may contribute to later substance use, causing downstream effects on sexual and pregnancy-related behaviors. We applied the life course perspective to qualitative interview findings conducted with women with criminal legal involvement to explore connections between participants' early exposure to drugs and childhood sexual abuse with subsequent engagement with substance use and sexual and reproductive behaviors. METHOD: We analyzed semistructured interviews with 33 racially diverse women with criminal legal involvement, Ages 18-65, who were recruited from a community organization in the Midwestern United States to explore their experiences and perspectives on factors that influenced their substance use and reproductive health behaviors. We used a modified grounded theory approach and retroactively applied the life course perspective model to inform and organize our data. RESULTS: Fifteen participants described exposure to substances and/or sexual abuse at a young age which played a role in influencing later life behaviors involving substance use and sexual and reproductive health. For some participants, the accumulation of experiences further contributed to shared pregnancy behaviors and outcomes including unexpected and rapid repeat pregnancies and difficulty abstaining from drug use while pregnant. CONCLUSIONS: Early life experiences may influence later life sexual and reproductive health behaviors. These experiences must be considered when engaging with women in patient-centered and trauma-informed ways in settings where they seek care including carceral facilities, obstetrics and gynecology and primary care clinics, and substance use disorder treatment programs. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Structural and computational design of a SARS-CoV-2 spike antigen with improved expression and immunogenicity.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern challenge the efficacy of approved vaccines, emphasizing the need for updated spike antigens. Here, we use an evolutionary-based design aimed at boosting protein expression levels of S-2P and improving immunogenic outcomes in mice. Thirty-six prototype antigens were generated in silico and 15 were produced for biochemical analysis. S2D14, which contains 20 computationally designed mutations within the S2 domain and a rationally engineered D614G mutation in the SD2 domain, has an ~11-fold increase in protein yield and retains RBD antigenicity. Cryo-electron microscopy structures reveal a mixture of populations in various RBD conformational states. Vaccination of mice with adjuvanted S2D14 elicited higher cross-neutralizing antibody titers than adjuvanted S-2P against the SARS-CoV-2 Wuhan strain and four variants of concern. S2D14 may be a useful scaffold or tool for the design of future coronavirus vaccines, and the approaches used for the design of S2D14 may be broadly applicable to streamline vaccine discovery.

Development and Implementation of an Academic and Professional Nursing Organization Partnership to Enhance Leadership Skills and Knowledge About HIV-Related Nursing Care Among Diverse, Prelicensure, Clinical Nurse Leader Scholars.

ABSTRACT: Historically, racial discrimination, few role models, and a general lack of support both in academic and professional contexts has hindered the education and career advancement of minority nursing students. The American Association of Colleges of Nursing (AACN), in its G uiding Principles for Academic-Practice Partnerships , describes the creation of an academic-professional nursing organization partnership to address barriers to the success of nursing students from underrepresented groups. In keeping with the AACN's guiding principles, the University of Maryland School of Nursing and the Association of Nurses in AIDS Care (ANAC) developed a partnership to deliver a multifaceted program for prelicensure, second-degree, Master of Science in Nursing, Clinical Nurse Leader Scholars which prepares them to address the health care needs of people living with HIV/AIDS and bolsters student leadership knowledge and skills. The objective of this article is to describe the program components, outcomes, and lessons learned from this academic-professional nursing organization partnership. The approach described may be useful for future partnerships designed to enhance leadership experiences and skills for minority nursing students and will hopefully be used to advocate for their success.

Real-World Data for Interdisciplinary Health Care Research: A Case Example.

Real-word data (RWD) refer to data relating to patient health status and/or the delivery of health care routinely collected from a variety of sources, including electronic health records, medical claims data, and patient-generated data. Data sets that combine personal health data stored in different sources can provide a more complete picture of an individual's health and can be used to improve population health through research and practice. The 2-tiered aim of this article is to provide a brief introduction to using RWD in health care research and to present a case study that demonstrates data curation and data merge from different sources while highlighting the benefits and limitations of using RWD. The current digital health ecosystem and value-based care approach highlight the need to use RWD to catalyze the advancement of health care research and practice. This is an excellent field that nurse researchers can lead, as they have an innate understanding of such data and data sources.

Academy of Clinical Essentials: A Revolutionary Nurse Staffing and Education Model.

A revolutionary academic-practice partnership model was implemented at the University of Maryland Medical System (UMMS) with the University of Maryland School of Nursing, through which the preparation and transition to practice of new graduate nurses were reimagined, resulting in intentional support for staffing the nursing workforce. Groups of nursing students were paired with a UMMS-funded clinical instructor to take a full patient assignment for one 12-hour shift in a UMMS hospital each week. This instructor-led cohort is equivalent to one UMMS nurse and was included in the staffing numbers of participating units.

Development of an academic-practice partnership model to anchor care coordination and population health.

The National Academy of Medicine's The Future of Nursing 2020-2030 recommends the expansion of the role of nurses throughout the continuum of health care in an effort to improve the health of the nation while decreasing costs. To accomplish this goal, nursing students and nurses must be well prepared to perform at their highest capacity to meet health care demands. Currently the U.S. health care delivery system is undergoing rapid changes that affect approaches to delivering care services. These changes call for education and practice reforms in nursing. This article introduces an innovative academic-practice partnership model (the University of Maryland Nursing [UMNursing] Care Coordination Implementation Collaborative), including its background, development, and blueprint for a large implementation project. The implementation model integrates nursing education and practice in areas of care co-ordination and population health, which have a significant impact on the Triple Aim of health. The project also uniquely integrates education, practice, and research, with the ultimate outcome of higher quality patient care.

Comparing organ donation decisions for next-of-kin versus the self: results of a national survey.

OBJECTIVES: Intensive care audits point to family refusal as a major barrier to organ donation. In this study, we sought to understand refusal by accounting for the decision-maker's mindset. This focused on: (1) how decisions compare when made on behalf of a relative (vs the self); and (2) confidence in decisions made for family members. DESIGN: Cross-sectional survey in Singapore. SETTING: Participants were recruited from community settings via door-to-door sampling and community eateries. PARTICIPANTS: 973 adults who qualified as organ donors in Singapore. RESULTS: Although 68.1% of participants were willing to donate their own organs, only 51.8% were willing to donate a relative's organs. Using machine learning, we found that consistency was predicted by: (1) religion, and (2) fears about organ donation. Conversely, participants who were willing to donate their own organs but not their relative's were less driven by these factors, and may instead have resorted to heuristics in decision-making. Finally, we observed how individuals were overconfident in their decision-making abilities: although 78% had never discussed organ donation with their relatives, the large majority expressed high confidence that they would respect their relatives' wishes on death. CONCLUSIONS: These findings underscore the distinct psychological processes involved when donation decisions are made for family members. Amidst a global shortage of organ donors, addressing the decision-maker's mindset (eg, overconfidence, the use of heuristics) may be key to actualizing potential donors identified in intensive care units.

Perspectives of Pregnant and Breastfeeding Women on Participating in Longitudinal Mother-Baby Studies Involving Electronic Health Records: Qualitative Study.

BACKGROUND: Electronic health records (EHRs) hold great potential for longitudinal mother-baby studies, ranging from assessing study feasibility to facilitating patient recruitment to streamlining study visits and data collection. Existing studies on the perspectives of pregnant and breastfeeding women on EHR use have been limited to the use of EHRs to engage in health care rather than to participate in research. OBJECTIVE: The aim of this study is to explore the perspectives of pregnant and breastfeeding women on releasing their own and their infants' EHR data for longitudinal research to identify factors affecting their willingness to participate in research. METHODS: We conducted semistructured interviews with pregnant or breastfeeding women from Alachua County, Florida. Participants were asked about their familiarity with EHRs and EHR patient portals, their comfort with releasing maternal and infant EHR data to researchers, the length of time of the data release, and whether individual research test results should be included in the EHR. The interviews were transcribed verbatim. Transcripts were organized and coded using the NVivo 12 software (QSR International), and coded data were thematically analyzed using constant comparison. RESULTS: Participants included 29 pregnant or breastfeeding women aged between 22 and 39 years. More than half of the sample had at least an associate degree or higher. Nearly all participants (27/29, 93%) were familiar with EHRs and had experience accessing an EHR patient portal. Less than half of the participants (12/29, 41%) were willing to make EHR data available to researchers for the duration of a study or longer. Participants' concerns about sharing EHRs for research purposes emerged in 3 thematic domains: privacy and confidentiality, transparency by the research team, and surrogate decision-making on behalf of infants. The potential release of sensitive or stigmatizing information, such as mental or sexual health history, was considered in the decisions to release EHRs. Some participants viewed the simultaneous use of their EHRs for both health care and research as potentially beneficial, whereas others expressed concerns about mixing their health care with research. CONCLUSIONS: This exploratory study indicates that pregnant and breastfeeding women may be willing to release EHR data to researchers if researchers adequately address their concerns regarding the study design, communication, and data management. Pregnant and breastfeeding women should be included in EHR-based research as long as researchers are prepared to address their concerns.

Perspectives of pregnant and breastfeeding women on longitudinal clinical studies that require non-invasive biospecimen collection - a qualitative study.

BACKGROUND: Investigation of the microbiome during early life has stimulated an increasing number of cohort studies in pregnant and breastfeeding women that require non-invasive biospecimen collection. The objective of this study was to explore pregnant and breastfeeding women's perspectives on longitudinal clinical studies that require non-invasive biospecimen collection and how they relate to study logistics and research participation. METHODS: We completed in-depth semi-structured interviews with 40 women who were either pregnant (n = 20) or breastfeeding (n = 20) to identify their understanding of longitudinal clinical research, the motivations and barriers to their participation in such research, and their preferences for providing non-invasive biospecimen samples. RESULTS: Perspectives on research participation were focused on breastfeeding and perinatal education. Participants cited direct benefits of research participation that included flexible childcare, lactation support, and incentives and compensation. Healthcare providers, physician offices, and social media were cited as credible sources and channels for recruitment. Participants viewed lengthy study visits and child protection as the primary barriers to research participation. The barriers to biospecimen collection were centered on stool sampling, inadequate instructions, and drop-off convenience. CONCLUSION: Women in this study were interested in participating in clinical studies that require non-invasive biospecimen collection, and motivations to participate center on breastfeeding and the potential to make a scientific contribution that helps others. Effectively recruiting pregnant or breastfeeding participants for longitudinal microbiome studies requires protocols that account for participant interests and consideration for their time.

A Qualitative Study of Pregnant Women's Perspectives on Antibiotic Use for Mom and Child: Implications for Developing Tailored Health Education Interventions.

The overutilization of antibiotics during pregnancy and early life are associated with adverse health outcomes for mothers and infants. In this study, we explored pregnant women's opinions and concerns of antibiotics and how perceptions may affect their health-related decision-making. We conducted 18 in-depth, semi-structured interviews with pregnant women and used the Health Belief Model (HBM) as a framework to analyze the data. We found that mothers generally understood the benefits of antibiotics and were aware that antibiotics are clinically effective for treating bacterial infections. Importantly, perceived barriers related to antibiotic use included concerns regarding the impact of antibiotics on breastfeeding efficacy, microbial health, and societal factors such as antimicrobial resistance. The prescription of antibiotics by a healthcare provider was a cue to action for women, as they trusted providers to recommend medications that were safe for them and their infants. Overall, mothers shared that receiving education on the effects of antibiotics would improve their self-efficacy and decision-making surrounding the use of antibiotics for treating illness. Implications for tailored perinatal health education interventions to enhance antibiotic use, knowledge, and decision-making are discussed.

Coexistence of oil droplets and lipid vesicles in propofol drug products.

Propofol is intravenously administered oil-in-water emulsion stabilized by egg lecithin phospholipids indicated for the induction and maintenance of general anesthesia or sedation. It is generally assumed to be structurally homogenous as characterized by commonly used dynamic light scattering technique and laser diffraction. However, the excessive amount of egg lecithin phospholipids added to the propofol formulation may, presumably, give rise to additional formation of lipid vesicles (i.e., vesicular structures consisting of a phospholipid bilayer). In this study, we investigate the use of high-resolution cryogenic transmission electron microscopy (cryo-TEM) in morphological characterization of four commercially available propofol drug products. The TEM result, for the first time, reveals that all propofol drug products contain lipid vesicles and oil droplet-lipid vesicle aggregated structures, in addition to oil droplets. Statistical analysis shows the size and ratio of the lipid vesicles varies across four different products. To evaluate the impact of such morphological differences on active pharmaceutical ingredient (API)'s distribution, we separate the lipid vesicle phase from other constituents via ultracentrifuge fractionation and determine the amount of propofol (2,6-diisopropylphenol) using high performance liquid chromatography (HPLC). The results indicate that a nearly negligible amount of API (i.e., NMT 0.25% of labeled content) is present in the lipid vesicles and is thus primarily distributed in the oil phase. As oil droplets are the primary drug carriers and their globule size are similar, the findings of various lipid vesicle composition and sizes among different propofol products do not affect their clinical outcomes.

Probing the mechanism of bupivacaine drug release from multivesicular liposomes.

The mechanism of drug release from complex dosage forms, such as multivesicular liposomes (MVLs), is complex and oftentimes sensitive to the release environment. This challenges the design and development of an appropriate in vitro release test (IVRT) method. In this study, a commercial bupivacaine MVL product was selected as a model product and an IVRT method was developed using a modified USP 2 apparatus in conjunction with reverse-dialysis membranes. This setup allowed the use of in situ UV-Vis probes to continuously monitor the drug concentration during release. In comparison to the traditional sample-and-separate methods, the new method allowed for better control of the release conditions allowing for study of the drug release mechanism. Bupivacaine (BPV) MVLs exhibited distinct tri-phasic release characteristics comprising of an initial burst release, lag phase and a secondary release. Temperature, pH, agitation speed and release media composition were observed to impact the mechanism and rate of BPV release from MVLs. The size and morphology of the MVLs as well as their inner vesicle compartments were analyzed using cryogenic-scanning electron microscopy (cryo-SEM), confocal laser scanning microscopy and laser diffraction, where the mean diameters of the MVLs and their inner "polyhedral" vesicles were found to be 23.6 ±â€¯11.5 µm and 1.52 ±â€¯0.44 µm, respectively. Cryo-SEM results further showed a decrease in particle size and loss of internal "polyhedral" structure of the MVLs over the duration of release, indicating erosion and rearrangement of the lipid layers. Based on these results a potential MVL drug release mechanism was proposed, which may assist with the future development of more biorelevant IVRT method for similar formulations.

Quality of life among survivors of early-stage cervical cancer in Taiwan: an exploration of treatment modality differences.

PURPOSE: Women with early-stage cervical cancer may experience changes in their quality of life (QoL) due to treatment or to the effects of the cancer. In this study, we examined differences in QoL by treatment modality between women who underwent surgery only and those treated with concurrent chemoradiation (CCRT). METHODS: The sample of 290 women had been diagnosed with stage I-II cervical cancer. Data were collected on these women's demographic and disease characteristics, general QoL, and cancer-specific QoL using an author-designed demographic-disease survey, the European Organization for Research and Treatment of Cancer QoL questionnaire, and the Taiwanese-version Cervical Cancer Module 24 questionnaire, respectively. Data were analyzed by descriptive statistics and analysis of covariance. RESULTS: Women with cervical cancer who underwent surgery only had significantly worse constipation and body image than those treated with CCRT. Women who underwent CCRT had worse physical and role functioning than those who underwent surgery only. Women who had CCRT also reported worse symptoms, such as fatigue, appetite loss, diarrhea, financial difficulties, sexual enjoyment, and sexual/vaginal functioning, than those who had only surgery. CONCLUSIONS: Our results add knowledge about QoL in women with early-stage cervical cancer who receive different treatment modalities. When suggesting treatment modalities for women with cervical cancer, health professionals should also consider changes in women's QoL after cancer treatment. To improve women's QoL after treatment, professionals should also offer timely and individualized interventions based on women's cervical cancer treatment.

Associations among menopausal symptoms, sleep and fatigue in Taiwanese women with endometrial cancer.

The purpose of this study was to explore the relationships among menopausal symptoms, sleep quality and fatigue in women with endometrial cancer. Participants were 95 women (mean age = 57.44 ± 10.15 years) diagnosed with endometrial cancer and who had completed their treatment before data collection. Each woman completed three structured questionnaires: the Functional Assessment of Cancer Therapy-Endocrine Symptoms (endocrine symptom subscale), the Pittsburgh Sleep Quality Index and the Functional Assessment of Chronic Illness Therapy-Fatigue. Participants' worst menopausal symptom was sexual pain. In addition, menopausal symptoms were worse in women with surgical menopause than with natural menopause. The majority of women had poor sleep quality (55%), and women with fatigue reported worse sleep quality and menopausal symptoms than those without fatigue. However, higher fatigue was significantly related to shorter time since diagnosis. Together, three variables (time since diagnosis, menopausal symptoms and sleep quality) explained 39% of the variance in fatigue, with menopausal symptoms being the strongest predictor. Healthcare providers can assess menopausal symptoms and sleep quality during and after treatment of women with endometrial cancer. Such assessments would allow timely interventions to alleviate fatigue and menopausal symptoms in this population, thus improving their quality of life.

Core size determination and structural characterization of intravenous iron complexes by cryogenic transmission electron microscopy.

Understanding physicochemical properties of intravenous (IV) iron drug products is essential to ensure the manufacturing process is consistent and streamlined. The history of physicochemical characterization of IV iron complex formulations stretches over several decades, with disparities in iron core size and particle morphology as the major source of debate. One of the main reasons for this controversy is room temperature sample preparation artifacts, which affect accurate determination of size, shape and agglomeration/aggregation of nanoscale iron particles. The present study is first to report the ultra-fine iron core structures of four IV iron complex formulations, sodium ferric gluconate, iron sucrose, low molecular weight iron dextran and ferumoxytol, using a cryogenic transmission electron microscopy (cryo-TEM) preservation technique, as opposed to the conventional room temperature (RT-TEM) technique. Our results show that room temperature preparation causes nanoparticle aggregation and deformation, while cryo-TEM preserves IV iron colloidal suspension in their native frozen-hydrated and undiluted state. In contrast to the current consensus in literature, all four IV iron colloids exhibit a similar morphology of their iron oxide cores with a spherical shape, narrow size distribution and an average size of 2nm. Moreover, out of the four tested formulations, ferumoxytol exhibits a cluster-like community of several iron carbohydrate particles which likely accounts for its large hydrodynamic size of 25nm, measured with dynamic light scattering. Our findings outline a suitable method for identifying colloidal nanoparticle core size in the native state, which is increasingly important for manufacturing and design control of complex drug formulations, such as IV iron drug products.

HIV-Testing Rates and Testing Locations Among Women Who Have Experienced Intimate Partner Violence: Data From the Centers for Disease Control Behavioral Risk Factor Surveillance System, 2006.

Data from the Centers for Disease Control and Prevention's (CDC) 2006 Behavioral Risk Factor Surveillance System were analyzed to report the HIV-testing rates and locations of women who have experienced intimate partner violence (IPV). Of the 18,917 women in the sample, 19.8% reported experiencing IPV. Over half of the women who experienced IPV reported testing rates of 52.4%, compared with 35.5% of the overall sample. Testing rates and locations significantly differed by race/ethnicity. Findings and their implications are explored, with an emphasis on increasing access to HIV testing and treatment for women who have experienced IPV and providing sexual safety planning for women accessing HIV-testing services.

Factors affecting sexual function: A comparison between women with gynecological or rectal cancer and healthy controls.

This study had two purposes: (i) to explore differences in sexual function between women with gynecological or rectal cancer after related pelvic-area treatments and women without cancer; and (ii) to investigate the relationships among body image, anxiety and depression, sexual relationship power, sexual self-schema, and female sexual function. The participants (n = 139) were recruited through Internet cancer support groups and women's health organizations in the USA. Six structured questionnaires were mailed, and the data were analyzed using descriptive and inferential statistics. The results showed that women with gynecological or rectal cancer had significantly worse sexual function than women without cancer. Having gynecological/rectal cancer and a negative sexual self-schema were significantly related to poor sexual function. Furthermore, sexual self-schema moderated the relationship between sexual relationship power and female sexual function. Healthcare providers could give more attention to sexual issues in women who have undergone treatment for gynecological or rectal cancer, especially for those with a negative sexual self-schema and high sexual relationship power, which might improve these women's quality of life.

Self-report versus performance measure in gauging level of function with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a debilitating, progressive disease with no known cure. Symptoms vary widely for persons with MS and measuring levels of fine motor, gross motor and cognitive function is a large part of assessing disease progression in both clinical and research settings. While self-report measures of function have advantages in cost and ease of administration, questions remain about the accuracy of such measures and the relationship of self-reports of functioning to performance measures of function. OBJECTIVE: The purpose of this study was to compare scores on a self-report measure of functional limitations with MS with a performance-based measure at five different time points. METHODS: Sixty participants in an ongoing longitudinal study completed two measures of function annually over a five-year period - the self-report Incapacity Status Scale and the MS Functional Composite (MSFC), a performance test. Pearson correlations were used to explore the association of self-report and performance scores. RESULTS: There were moderate to strong correlations among the ISS total (r = -.53 to -.63, p < .01) and subscale scores of gross (r = .79 to .87; p < .01)) and fine (r = .47 to .69; p < .01) motor function and the corresponding MSFC performance measure. The pattern of change over time in most scores on self-report and performance measures was similar. CONCLUSION: Findings suggest that the self-report measure examined here, which has advantages in terms of feasibility of administration and patient burden, does relate to performance measurement, particularly in the area of gross motor function, but it may not adequately reflect cognitive function.

Comparative cytotoxicity of nanosilver in human liver HepG2 and colon Caco2 cells in culture.

The use of silver nanoparticles in food, food contact materials, dietary supplements and cosmetics has increased significantly owing to their antibacterial and antifungal properties. As a consequence, the need for validated rapid screening methods to assess their toxicity is necessary to ensure consumer safety. This study evaluated two widely used in vitro cell culture models, human liver HepG2 cells and human colon Caco2 cells, as tools for assessing the potential cytotoxicity of food- and cosmetic-related nanoparticles. The two cell culture models were utilized to compare the potential cytotoxicity of 20-nm silver. The average size of the silver nanoparticle determined by our transmission electron microscopy (TEM) analysis was 20.4 nm. The dynamic light scattering (DLS) analysis showed no large agglomeration of the silver nanoparticles. The concentration of the 20-nm silver solution determined by our inductively coupled plasma-mass spectrometry (ICP-MS) analysis was 0.962 mg ml(-1) . Our ICP-MS and TEM analysis demonstrated the uptake of 20-nm silver by both HepG2 and Caco2 cells. Cytotoxicity, determined by the Alamar Blue reduction assay, was evaluated in the nanosilver concentration range of 0.1 to 20 µg ml(-1) . Significant concentration-dependent cytotoxicity of the nanosilver in HepG2 cells was observed in the concentration range of 1 to 20 µg ml(-1) and at a higher concentration range of 10 to 20 µg ml(-1) in Caco2 cells compared with the vehicle control. A concentration-dependent decrease in dsDNA content was observed in both cell types exposed to nanosilver but not controls, suggesting an increase in DNA damage. The DNA damage was observed in the concentration range of 1 to 20 µg ml(-1) . Nanosilver-exposed HepG2 and Caco2 cells showed no cellular oxidative stress, determined by the dichlorofluorescein assay, compared with the vehicle control in the concentration range used in this study. A concentration-dependent decrease in mitochondria membrane potential in both nanosilver exposed cell types suggested increased mitochondria injury compared with the vehicle control. The mitochondrial injury in HepG2 cells was significant in the concentration range of 1 to 20 µg ml(-1) , but in Caco2 cells it was significant at a higher concentration range of 10 to 20 µg ml(-1) . These results indicated that HepG2 cells were more sensitive to nanosilver exposure than Caco2 cells. It is generally believed that cellular oxidative stress induces cytotoxicity of nanoparticles. However, in this study we did not detect any nanosilver-induced oxidative stress in either cell type at the concentration range used in this study. Our results suggest that cellular oxidative stress did not play a major role in the observed cytotoxicity of nanosilver in HepG2 and Caco2 cells and that a different mechanism of nanosilver-induced mitochondrial injury leads to the cytotoxicity. The HepG2 and Caco2 cells used this study appear to be targets for silver nanoparticles. The results of this study suggest that the differences in the mechanisms of toxicity induced by nanosilver may be largely as a consequence of the type of cells used. This differential rather than universal response of different cell types exposed to nanoparticles may play an important role in the mechanism of their toxicity. In summary, the results of this study indicate that the widely used in vitro models, HepG2 and Caco2 cells in culture, are excellent systems for screening cytotoxicity of silver nanoparticles. These long established cell culture models and simple assays used in this study can provide useful toxicity and mechanistic information that can help to better inform safety assessments of food- and cosmetic-related silver nanoparticles.