Evaluating the immunologically "cold" tumor microenvironment after treatment with immune checkpoint inhibitors utilizing PET imaging of CD4 + and CD8 + T cells in breast cancer mouse models.

BACKGROUND: Immune-positron emission tomography (PET) imaging with tracers that target CD8 and granzyme B has shown promise in predicting the therapeutic response following immune checkpoint blockade (ICB) in immunologically "hot" tumors. However, immune dynamics in the low T-cell infiltrating "cold" tumor immune microenvironment during ICB remain poorly understood. This study uses molecular imaging to evaluate changes in CD4 + T cells and CD8 + T cells during ICB in breast cancer models and examines biomarkers of response. METHODS: [89Zr]Zr-DFO-CD4 and [89Zr]Zr-DFO-CD8 radiotracers were used to quantify changes in intratumoral and splenic CD4 T cells and CD8 T cells in response to ICB treatment in 4T1 and MMTV-HER2 mouse models, which represent immunologically "cold" tumors. A correlation between PET quantification metrics and long-term anti-tumor response was observed. Further biological validation was obtained by autoradiography and immunofluorescence. RESULTS: Following ICB treatment, an increase in the CD8-specific PET signal was observed within 6 days, and an increase in the CD4-specific PET signal was observed within 2 days in tumors that eventually responded to immunotherapy, while no significant differences in CD4 or CD8 were found at the baseline of treatment that differentiated responders from nonresponders. Furthermore, mice whose tumors responded to ICB had a lower CD8 PET signal in the spleen and a higher CD4 PET signal in the spleen compared to non-responders. Intratumoral spatial heterogeneity of the CD8 and CD4-specific PET signals was lower in responders compared to non-responders. Finally, PET imaging, autoradiography, and immunofluorescence signals were correlated when comparing in vivo imaging to ex vivo validations. CONCLUSIONS: CD4- and CD8-specific immuno-PET imaging can be used to characterize the in vivo distribution of CD4 + and CD8 + T cells in response to immune checkpoint blockade. Imaging metrics that describe the overall levels and distribution of CD8 + T cells and CD4 + T cells can provide insight into immunological alterations, predict biomarkers of response to immunotherapy, and guide clinical decision-making in those tumors where the kinetics of the response differ.

Total sleep deprivation effects on the attentional blink.

The Attentional Blink (AB) is a phenomenon that reflects difficulty in detecting or identifying the second of two successive targets (T1 and T2) that are presented in rapid succession, between 200-500ms apart. The AB involves indicators of attentional and temporal integration mechanisms related to the early stages of visual processing. The aim of this study was to identify the effects of 24-h of sleep deprivation (total sleep deprivation, TSD) on the attentional and temporal integration mechanisms of the AB. Twenty-two undergraduate students were recorded during five successive days, in these three conditions: baseline (two days), TSD (one day), and recovery (two days). Each day, at around 12:00 h, participants responded to a Rapid Serial Visual Presentation task (RSVP) that presented two targets separated by random intervals from 100 to 1000ms. The attentional mechanisms were assessed by the AB presence, the AB magnitude, and the AB interval, while the temporal integration mechanisms were evaluated by lag-1 sparing and order reversal responses. TSD negatively affected the attentional mechanisms, which is expressed by an overall reduction in performance, an extended AB interval, and a reduced AB magnitude. TSD also negatively affected the temporal integration mechanisms, manifested by an absence of lag-1 sparing and an increase in order reversals. These results suggest that people are still able to respond to two successive stimuli after 24 h without sleep. However, it becomes more difficult to respond to both stimuli because the attentional and temporal integration mechanisms of the AB are impaired.

Epilepsy with eyelid myoclonia (Jeavons syndrome): Generalized, focal, or combined generalized and focal epilepsy syndrome?

Epilepsy with eyelid myoclonia (EM) or Jeavons syndrome (JS) is an epileptic syndrome related to the spectrum of genetic generalized epilepsies (GGE). We report two untreated children on which EEGs were performed several hours after a generalized tonic-clonic seizure (GTCS). These showed a unilateral, nearly continuous posterior slowing. This slow-wave activity was associated with contralateral epileptiform activity in one case, while in the second case, it was associated with an ipsilateral activity. However, in the latter child, a few months later an independent focus on the contralateral side was observed. A diagnosis of focal occipital lobe epilepsy was proposed in both cases, and one child underwent a left occipital lobectomy at 3.5 years of age. Despite surgery, absences with EM persisted in this child, and a marked photosensitivity to photic stimulation was observed two years later. The focal slow wave activity of one occipital lobe several hours after a GTCS in these two subjects was in favor of a focal onset preceding the generalization. The EEG evidence for independent left and right posterior focus in these two cases, the persistence of EM, and the development of a marked photosensitivity to photic stimulation in the child who underwent an occipital lobectomy, allow us to suggest that JS is associated with a network of bi-occipital hyperexcitability that rapidly engages bilaterally to produce generalized seizures.

Dual anti-HER2/EGFR inhibition synergistically increases therapeutic effects and alters tumor oxygenation in HNSCC.

Epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and hypoxia are associated with radioresistance. The goal of this study is to study the synergy of anti-HER2, trastuzumab, and anti-EGFR, cetuximab, and characterize the tumor microenvironment components that may lead to increased radiation sensitivity with dual anti-HER2/EGFR therapy in head and neck squamous cell carcinoma (HNSCC). Positron emission tomography (PET) imaging ([89Zr]-panitumumab and [89Zr]-pertuzumab) was used to characterize EGFR and HER2 in HNSCC cell line tumors. HNSCC cells were treated with trastuzumab, cetuximab, or combination followed by radiation to assess for viability and radiosensitivity (colony forming assay, immunofluorescence, and flow cytometry). In vivo, [18F]-FMISO-PET imaging was used to quantify changes in oxygenation during treatment. Bliss Test of Synergy was used to identify combination treatment synergy. Quantifying EGFR and HER2 receptor expression revealed a 50% increase in heterogeneity of HER2 relative to EGFR. In vitro, dual trastuzumab-cetuximab therapy shows significant decreases in DNA damage response and increased response to radiation therapy (p < 0.05). In vivo, tumors treated with dual anti-HER2/EGFR demonstrated decreased tumor hypoxia, when compared to single agent therapies. Dual trastuzumab-cetuximab demonstrates synergy and can affect tumor oxygenation in HNSCC. Combination trastuzumab-cetuximab modulates the tumor microenvironment through reductions in tumor hypoxia and induces sustained treatment synergy.

[89Zr]-CD8 ImmunoPET imaging of glioblastoma multiforme response to combination oncolytic viral and checkpoint inhibitor immunotherapy reveals CD8 infiltration differential changes in preclinical models.

Rationale: Novel immune-activating therapeutics for the treatment of glioblastoma multiforme (GBM) have shown potential for tumor regression and increased survival over standard therapies. However, immunotherapy efficacy remains inconsistent with response assessment being complicated by early treatment-induced apparent radiological tumor progression and slow downstream effects. This inability to determine early immunotherapeutic benefit results in a drastically decreased window for alternative, and potentially more effective, treatment options. The objective of this study is to evaluate the effects of combination immunotherapy on early CD8+ cell infiltration and its association with long term response in orthotopic syngeneic glioblastoma models. Methods: Luciferase positive GBM orthotopic mouse models (GSC005-luc) were imaged via [89Zr]-CD8 positron emission tomography (PET) one week following treatment with saline, anti-PD1, M002 oncolytic herpes simplex virus (oHSV) or combination immunotherapy. Subsequently, brains were excised, imaged via [89Zr]-CD8 ImmunoPET and evaluated though autoradiography and histology for H&E and CD8 immunohistochemistry. Longitudinal immunotherapeutic effects were evaluated through [89Zr]-CD8 PET imaging one- and three-weeks following treatment, with changes in tumor volume monitored on a three-day basis via bioluminescence imaging (BLI). Response classification was then performed based on long-term BLI signal changes. Statistical analysis was performed between groups using one-way ANOVA and two-sided unpaired T-test, with p < 0.05 considered significant. Correlations between imaging and biological validation were assessed via Pearson's correlation test. Results: [89Zr]-CD8 PET standardized uptake value (SUV) quantification was correlated with ex vivo SUV quantification (r = 0.61, p < 0.01), autoradiography (r = 0.46, p < 0.01), and IHC tumor CD8+ cell density (r = 0.55, p < 0.01). Classification of therapeutic responders, via bioluminescence signal, revealed a more homogeneous CD8+ immune cell distribution in responders (p < 0.05) one-week following immunotherapy. Conclusions: Assessment of early CD8+ cell infiltration and distribution in the tumor microenvironment provides potential imaging metrics for the characterization of oHSV and checkpoint blockade immunotherapy response in GBM. The combination therapies showed enhanced efficacy compared to single agent immunotherapies. Further development of immune-focused imaging methods can provide clinically relevant metrics associated with immune cell localization that can inform immunotherapeutic efficacy and subsequent treatment response in GBM patients.

Voltage-Gated Sodium Channel NaV1.7 Inhibitors with Potent Anticancer Activities in Medullary Thyroid Cancer Cells.

Our results from quantitative RT-PCR, Western blotting, immunohistochemistry, and the tissue microarray of medullary thyroid cancer (MTC) cell lines and patient specimens confirm that VGSC subtype NaV1.7 is uniquely expressed in aggressive MTC and not expressed in normal thyroid cells and tissues. We establish the druggability of NaV1.7 in MTC by identifying a novel inhibitor (SV188) and investigate its mode of binding and ability to inhibit INa current in NaV1.7. The whole-cell patch-clamp studies of the SV188 in the NaV1.7 channels expressed in HEK-293 cells show that SV188 inhibited the INa current in NaV1.7 with an IC50 value of 3.6 µM by a voltage- and use-dependent blockade mechanism, and the maximum inhibitory effect is observed when the channel is open. SV188 inhibited the viability of MTC cell lines, MZ-CRC-1 and TT, with IC50 values of 8.47 µM and 9.32 µM, respectively, and significantly inhibited the invasion of MZ-CRC-1 cells by 35% and 52% at 3 µM and 6 µM, respectively. In contrast, SV188 had no effect on the invasion of TT cells derived from primary tumor, which have lower basal expression of NaV1.7. In addition, SV188 at 3 µM significantly inhibited the migration of MZ-CRC-1 and TT cells by 27% and 57%, respectively.

Evaluation of a CD206-Targeted Peptide for PET Imaging of Macrophages in Syngeneic Mouse Models of Cancer.

Tumor-associated macrophages (TAMs) are large phagocytic cells that play numerous roles in cancer biology and are an important component of the relationship between immune system response and tumor progression. The peptide, RP832c, targets the Mannose Receptor (CD206) expressed on M2-like macrophages and is cross-reactive to both human and murine CD206. Additionally, it exhibits therapeutic properties through its ability to shift the population of TAMs from an M2-like (protumor) toward an M1-like phenotype (antitumor) and has demonstrated promise in inhibiting tumor resistance in PD-L1 unresponsive melanoma murine models. In addition, it has shown inhibition in bleomycin-induced pulmonary fibrosis through interactions with CD206 macrophages.1,2 Our work aims to develop a novel CD206 positron emission tomography (PET) imaging probe based on RP832c (Kd = 5.64 µM) as a direct, noninvasive method for the assessment of TAMs in mouse models of cancer. We adapted RP832c to incorporate the chelator DOTA to allow for radiolabeling with the PET isotope 68Ga (t1/2 = 68 min; ß+ = 89%). In vitro stability studies were conducted in mouse serum up to 3 h. The in vitro binding characteristics of [68Ga]RP832c to CD206 were determined by a protein plate binding assay and Surface Plasmon Resonance (SPR). PET imaging and biodistribution studies were conducted in syngeneic tumor models. Stability studies in mouse serum demonstrated that 68Ga remained complexed up to 3 h (less than 1% free 68Ga). Binding affinity studies demonstrated high binding of [68Ga]RP832c to mouse CD206 protein and that the binding of the tracer was able to be blocked significantly when incubated with a blocking solution of native RP832c. PET imaging and biodistribution studies in syngeneic tumor models demonstrated uptake in tumor and CD206 expressing organs of [68Ga]RP832c. A significant correlation was found between the percentage of CD206 present in each tumor imaged with [68Ga]RP832c and PET imaging mean standardized uptake values in a CT26 mouse model of cancer. The data shows that [68Ga]RP832c represents a promising candidate for macrophage imaging in cancer and other diseases.

Mathematical Model of Triple-Negative Breast Cancer in Response to Combination Chemotherapies.

Triple-negative breast cancer (TNBC) is a heterogenous disease that is defined by its lack of targetable receptors, thus limiting treatment options and resulting in higher rates of metastasis and recurrence. Combination chemotherapy treatments, which inhibit tumor cell proliferation and regeneration, are a major component of standard-of-care treatment of TNBC. In this manuscript, we build a coupled ordinary differential equation model of TNBC with compartments that represent tumor proliferation, necrosis, apoptosis, and immune response to computationally describe the biological tumor affect to a combination of chemotherapies, doxorubicin (DRB) and paclitaxel (PTX). This model is parameterized using longitudinal [18F]-fluorothymidine positron emission tomography (FLT-PET) imaging data which allows for a noninvasive molecular imaging approach to quantify the tumor proliferation and tumor volume measurements for two murine models of TNBC. Animal models include a human cell line xenograft model, MDA-MB-231, and a syngeneic 4T1 mammary carcinoma model. The mathematical models are parameterized and the percent necrosis at the end time point is predicted and validated using histological hematoxylin and eosin (H&E) data. Global Sobol' sensitivity analysis is conducted to further understand the role each parameter plays in the model's goodness of fit to the data. In both the MDA-MB-231 and the 4T1 tumor models, the designed mathematical model can accurately describe both tumor volume changes and final necrosis volume. This can give insight into the ordering, dosing, and timing of DRB and PTX treatment. More importantly, this model can also give insight into future novel combinations of therapies and how the immune system plays a role in therapeutic response to TNBC, due to its calibration to two types of TNBC murine models.

Evaluating the Accuracy of FUCCI Cell Cycle In Vivo Fluorescent Imaging to Assess Tumor Proliferation in Preclinical Oncology Models.

PURPOSE: The primary goal of this study is to evaluate the accuracy of the fluorescence ubiquitination cell cycle indicator (FUCCI) system with fluorescence in vivo imaging compared to 3'-deoxy-3'-[18F]fluorothymidine ([18F]-FLT) positron emission tomography (PET)/computed tomography (CT) and biological validation through histology. Imaging with [18F]-FLT PET/CT can be used to noninvasively assess cancer cell proliferation and has been utilized in both preclinical and clinical studies. However, a cost-effective and straightforward method for in vivo, cell cycle targeted cancer drug screening is needed prior to moving towards translational imaging methods such as PET/CT. PROCEDURES: In this study, fluorescent MDA-MB-231-FUCCI tumor growth was monitored weekly with caliper measurements and fluorescent imaging. Seven weeks post-injection, [18F]-FLT PET/CT was performed with a preclinical PET/CT, and tumors samples were harvested for histological analysis. RESULTS: RFP fluorescent signal significantly correlated with tumor volume (r = 0.8153, p < 0.0001). Cell proliferation measured by GFP fluorescent imaging was correlated with tumor growth rate (r = 0.6497, p < 0.001). Also, GFP+ cells and [18F]-FLT regions of high uptake were both spatially located in the tumor borders, indicating that the FUCCI-IVIS method may provide an accurate assessment of tumor heterogeneity of cell proliferation. The quantification of total GFP signal was correlated with the sum of tumor [18F]-FLT standard uptake value (SUV) (r = 0.5361, p = 0.0724). Finally, histological analysis confirmed viable cells in the tumor and the correlation of GFP + and Ki67 + cells (r = 0.6368, p = 0.0477). CONCLUSION: Fluorescent imaging of the cell cycle provides a noninvasive accurate depiction of tumor progression and response to therapy, which may benefit in vivo testing of novel cancer therapeutics that target the cell cycle.

Estrategias de afrontamiento en adultos de la zona centro-sur de Chile durante la contingencia sanitaria por COVID-19 / Coping Strategies in Adults in the Central-South Zone of Chile, During the Health Contingency due to COVID-19

Resumen El objetivo de la investigación fue determinar las estrategias de afrontamiento personales y familiares en el desarrollo de la experiencia de confinamiento, por causa de la contingencia sanitaria por COVID-19, en población adulta de la zona centro-sur de Chile. El estudio fue de tipo cuantitativo, con un diseño de tipo transversal, asociativo. La muestra estuvo compuesta por 251 personas, 139 (55.4%) mujeres y 112 (44.6%) hombres, con un rango etario de 18 a 40 años. Los instrumentos aplicados fueron el Inventario de Estrategias de Afrontamiento (CSI) y la Escala de Evaluación Personal del Funcionamiento Familiar en Situaciones de Crisis (F-COPE). El análisis de los datos se realizó al emplear SPSS 22 y considerar un intervalo de confianza del 95% para el desarrollo de estadística descriptiva, pruebas de diferencias de medias t de Student, pruebas de correlación r de Pearson y ANOVA de una vía. Los resultados muestran que el afrontamiento individual se relaciona positivamente con el familiar, encontrando diferencias significativas según género y edad. Se discuten los hallazgos de acuerdo a los antecedentes teóricos y empíricos revisados.

Abstract: The aim of the research was to determine the personal and family coping strategies as the confinement experience developed, due to the COVID-19 health contingency, in an adult population of the south-central zone of Chile. The study was quantitative, with a cross-sectional, associative design. The sample consisted of 251 young adults, 139 (55.4%) women, and 112 (44.6%) men, with an age range of 18 to 40 years. The instruments applied were the Coping Strategies Inventory (CSI) and the Personal Evaluation Scale of Family Functioning in Crisis Situations (F-COPE). Data analysis was performed using descriptive statistics, Pearson's r correlation tests, Student's t-test, and one-way ANOVA. The results show that an individual's coping is positively related to his/her family one, with significant differences according to gender and age. The findings are discussed according to the reviewed theoretical and empirical background.

Three novel quantum-inspired swarm optimization algorithms using different bounded potential fields.

Based on the behavior of the quantum particles, it is possible to formulate mathematical expressions to develop metaheuristic search optimization algorithms. This paper presents three novel quantum-inspired algorithms, which scenario is a particle swarm that is excited by a Lorentz, Rosen-Morse, and Coulomb-like square root potential fields, respectively. To show the computational efficacy of the proposed optimization techniques, the paper presents a comparative study with the classical particle swarm optimization (PSO), genetic algorithm (GA), and firefly algorithm (FFA). The algorithms are used to solve 24 benchmark functions that are categorized by unimodal, multimodal, and fixed-dimension multimodal. As a finding, the algorithm inspired in the Lorentz potential field presents the most balanced computational performance in terms of exploitation (accuracy and precision), exploration (convergence speed and acceleration), and simulation time compared to the algorithms previously mentioned. A deeper analysis reveals that a strong potential field inside a well with weak asymptotic behavior leads to better exploitation and exploration attributes for unimodal, multimodal, and fixed-multimodal functions.

Ethnic Disparities in Nutritional Status among Older Adults: Evidence from the Survey of Health, Welfare and Aging (SABE) Ecuador.

This study aims to identify those populations that should be targeted by specific interventions. A cross-sectional design was utilized. Ordered logistic regression analysis was utilized to assess the association between ethnic identity and risk of malnutrition. Data were drawn from Ecuador's Survey of Health, Welfare and Aging (SABE). The final sample consisted of 4,572 people who were 60 years or older who were able to provide responses to the survey by themselves. Ethnic identity was categorized into four: indigenous, mestizo (Spanish and Indigenous mixed heritage), Afro-Ecuadorian/mulato, and other. Risk of malnutrition was measured using Mini Nutritional Assessment Short-Form (MNA-SF). A range of covariates were selected from three groups of factors: sociodemographic, health-related, and social network. Results revealed that the indigenous ethnicity was the only group who had significantly higher risk of malnutrition compared to mestizo even after controlling for a range of covariates including socio-economic status, health related factors, and social support. Findings suggest the existence of underlaying factors hindering the risk of malnutrition among indigenous older adults. Considering the information revealed by SABE, interventions and other strategies should be targeted and designed specifically accounting for the needs, preferences, and culture of the most vulnerable population.

Circadian and homeostatic modulation of the attentional blink.

An important property of attention is the limitation to process new information after responding to a stimulus. This property of attention can be evaluated by the Attentional Blink (AB), a phenomenon that consists of a failure to detect the second of two targets when the interval between them is 200-500 ms. The aim of the present work is to determine the possible existence of time awake (homeostatic changes) and time of day (circadian rhythm) variations in the AB. Eighteen undergraduate students, 11 men and 7 women, age = 18.06 ± 1.16 years, participated voluntarily in this research. They were recorded in a constant routine protocol during 29 h, in which rectal temperature was recorded every minute, while subjective sleepiness and responses to a Rapid Serial Visual Presentation (RSVP) task, to measure the AB, were recorded every hour. Homeostatic and circadian variations in all parameters of the RSVP task were observed, including changes in the capacity to process a new stimulus (Target 1 accuracy), a second stimulus occurring in a short interval after the first (Target 2 accuracy at lag 2, 200 ms) and to process another successive independent stimulus (Target 2 accuracy at lag 8, 800 ms). The acrophase of these parameters occurred with a phase delay of 2 h compared to the circadian rhythm of rectal temperature. The AB magnitude, an index of the AB, showed a decline with time awake, but no variations with time of day. In conclusion, there are homeostatic and circadian variations in the capacity to process any incoming information, especially in tasks with brief duration stimuli presented at a high frequency.

Cracking the Egg Potential: Traditional Knowledge, Attitudes, and Practices in a Food-Based Nutrition Intervention in Highland Ecuador.

BACKGROUND: Food-based interventions can reduce the prevalence of undernutrition and improve household food security, but nutritious and accessible foods may be underutilized. In Ecuador, eggs are inexpensive and widely available, but while they are a valuable source of essential nutrients for infants and young children, medical advice and community-based information have limited their inclusion in infants' diets. OBJECTIVE: A qualitative component was conducted to understand local perceptions, knowledge, and practices to complement a randomized control trial that studied the effect of introducing eggs on nutritional status and growth in infants from 6 to 9 months in rural communities in the highland province of Cotopaxi, Ecuador. METHODS: The qualitative inquiry consisted of key informant interviews, focus group discussions (FGDs), and structured observations in order to understand perceptions, knowledge, and practices related to household egg consumption and to the introduction of eggs in infants' diets. RESULTS: The two principal findings were that: (i) eggs are an available and culturally acceptable food source although they are not always a part of the diet; and (ii) perceptions and practices related to household consumption and the introduction of eggs into the diet of infants are shaped by local knowledge and practices, which are shaped by biomedical information and advice provided by public health professionals. CONCLUSION: Through an effective food-based intervention that includes qualitative research and a social marketing component, the behaviors of mothers and other caregivers can be modified, enabling children to realize the nutritional advantages of early introduction of eggs into their diet.

Discourse versus practice: are traditional practices and beliefs in pregnancy and childbirth included or excluded in the Ecuadorian health care system?

Background: Traditional beliefs, knowledge and practices are formally integrated into the Ecuadorian health system. We sought to understand whether they are integrated in practice. Methods: Qualitative data were collected in two rural parishes in the central highlands of Ecuador through four focus group discussions (30 participants), eight key informant interviews, three participatory exercises (24 participants), structured observations of health facilities and analysis of official documents. Results: We found different levels of integration, coexistence, tolerance, and intolerance of traditional health beliefs and practices in health facilities. One parish has undergone dramatic social and cultural transformation, and the role of traditional birth attendants is limited. In the other parish, traditional indigenous norms and values persist, and traditional birth attendants are sought during pregnancy and childbirth. The degree to which traditional birth attendants, indigenous women and their families are included or excluded from public health services depends largely on decisions taken by local health professionals. Conclusions: Formal policies in Ecuador stipulate that health care should be intercultural, but the role of traditional birth attendants is not necessarily incorporated in practice. The integration of culturally-informed beliefs and practices is critical for providing appropriate health services to members of vulnerable populations.

Aging, health, and identity in Ecuador's indigenous communities.

Middle-income countries like Ecuador are in the process of demographic and epidemiological transitions, and their populations are aging. The challenges associated with providing services to growing numbers of citizens who experience the inevitable deterioration associated with aging are mirrored by the manner in which aging is perceived in a culturally heterogeneous society. This paper presents the results of qualitative research conducted among older men and women in indigenous communities in the Ecuadorian highlands in order to investigate the perceptions regarding the ability of family and community networks to provide adequate and appropriate support for older persons in the context of their perceptions of health, health care, and aging. The principal findings are that: (i) perceptions of aging are shaped by chronic illness, fatigue, deteriorating sensory capacities, and vulnerability to accidents; (ii) barriers to health care are exacerbated among aging members of indigenous communities, although in some cases they can be addressed through traditional alternatives; (iii) the sense of identity shifts as aging people are increasingly unable to work the land and participate in community activities; and (iv) family and community support networks for older adults are not as strong as is generally thought. These findings represent the context within which issues related aging in a culturally heterogeneous society can be best understood and addressed.