Dataset Information

24-hour IOP telemetry in the nonhuman primate: implant system performance and initial characterization of IOP at multiple timescales.

ABSTRACT:

Purpose

IOP is the most common independent risk factor for development and progression of glaucoma, but very little is known about IOP dynamics. Continuous IOP telemetry was used in three nonhuman primates to characterize IOP dynamics at multiple time scales for multiple 24-hour periods.

Methods

An existing implantable telemetric pressure transducer system was adapted to monitoring anterior chamber IOP. The system records 500 IOP, ECG, and body temperature measurements per second and compensates for barometric pressure in real time. The continuous IOP signal was digitally filtered for noise and dropout and reported using time-window averaging for 19, 18, and 4 24-hour periods in three animals, respectively. Those data were analyzed for a nycthemeral pattern within each animal.

Results

Ten-minute time-window averaging for multiple 24-hour periods showed that IOP fluctuated from 7 to 14 mm Hg during the day, and those changes occurred frequently and quickly. Two-hour time-window averages of IOP for multiple 24-hour periods in three animals showed a weak nycthemeral trend, but IOP was not repeatable from day-to-day within animals.

Conclusions

The measured IOP was successfully measured continuously by using a new, fully implantable IOP telemetry system. IOP fluctuates as much as 10 mm Hg from day to day and hour to hour in unrestrained nonhuman primates, which indicates that snapshot IOP measurements may be inadequate to capture the true dynamic character of IOP. The distributions, magnitudes, and patterns of IOP are not reproducible from day to day within animals, but IOP tends to be slightly higher at night when IOP data are averaged across multiple 24-hour periods within animals.

SUBMITTER: Downs JC

PROVIDER: S-EPMC3183973 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Parthenogenesis is the biological phenomenon by which embryonic development is initiated without male contribution. Whereas parthenogenesis is a common mode of reproduction in lower organisms, the mammalian parthenote fails to produce a successful pregnancy. We herein describe in vitro parthenogenetic development of monkey (Macaca fascicularis) eggs to the blastocyst stage, and their use to create a pluripotent line of stem cells. These monkey stem cells (Cyno-1 cells) are positive for telomerase activity and are immunoreactive for alkaline phosphatase, octamer-binding transcription factor 4 (Oct-4), stage-specific embryonic antigen 4 (SSEA-4), tumor rejection antigen 1-60 (TRA 1-60), and tumor rejection antigen 1-81 (TRA 1-81) (traditional markers of human embryonic stem cells). They have a normal chromosome karyotype (40 + 2) and can be maintained in vitro in an undifferentiated state for extended periods of time. Cyno-1 cells can be differentiated in vitro into dopaminergic and serotonergic neurons, contractile cardiomyocyte-like cells, smooth muscle, ciliated epithelia, and adipocytes. When Cyno-1 cells were injected into severe combined immunodeficient mice, teratomas with derivatives from all three embryonic germ layers were obtained. When grown on fibronectin/laminin-coated plates and in neural progenitor medium, Cyno-1 cells assume a neural precursor phenotype (immunoreactive for nestin). However, these cells remain proliferative and express no functional ion channels. When transferred to differentiation conditions, the nestin-positive precursors assume neuronal and epithelial morphologies. Over time, these cells acquire electrophysiological characteristics of functional neurons (appearance of tetrodotoxin-sensitive, voltage-dependent sodium channels). These results suggest that stem cells derived from the parthenogenetically activated nonhuman primate egg provide a potential source for autologous cell therapy in the female and bypass the need for creating a competent embryo.

Project description:ImportanceEvidence regarding the nature and prevalence of 24-hour activity pattern phenotypes in older adults, especially those related to depression symptoms and cognition, is needed to guide the development of targeted mechanism research and behavioral interventions.ObjectivesTo identify subgroups of older adults with similar 24-hour activity rhythm characteristics and characterize associated depression symptoms and cognitive performance.Design, setting, and participantsFrom January to March 2022, a cross-sectional analysis of the 2011-2014 National Health and Nutrition Examination and Survey (NHANES) accelerometer study was conducted. The NHANES used a multistage probability sample that was designed to be representative of noninstitutionalized adults in the US. The main analysis included participants 65 years or older who had accelerometer and depression measures weighted to represent approximately 32 million older adults.ExposuresLatent profile analysis identified subgroups with similar 24-hour activity pattern characteristics as measured using extended-cosine and nonparametric methods.Main outcomes and measuresCovariate-adjusted sample-weighted regressions assessed associations of subgroup membership with (1) depression symptoms defined as 9-Item Patient Health Questionnaire (PHQ-9) scores of 10 or greater (PHQ-9) and (2) having at least psychometric mild cognitive impairment (p-MCI) defined as scoring less than 1 SD below the mean on a composite cognitive performance score.ResultsThe actual clustering sample size was 1800 (weighted: mean [SD] age, 72.9 [7.3] years; 57% female participants). Clustering identified 4 subgroups: (1) 677 earlier rising/robust (37.6%), (2) 587 shorter active period/less modelable (32.6%), (3) 177 shorter active period/very weak (9.8%), and (4) 359 later settling/very weak (20.0%). The prevalence of a PHQ-9 score of 10 or greater differed significantly across groups (cluster 1, 3.5%; cluster 2, 4.7%; cluster 3, 7.5%; cluster 4, 9.0%; χ2 P = .004). The prevalence of having at least p-MCI differed significantly across groups (cluster 1, 7.2%; cluster 2, 12.0%; cluster 3, 21.0%; cluster 4, 18.0%; χ2 P < .001). Five of 9 depression symptoms differed significantly across subgroups.Conclusions and relevanceIn this cross-sectional study, findings indicate that approximately 1 in 5 older adults in the US may be classified in a subgroup with weak activity patterns and later settling, and approximately 1 in 10 may be classified in a subgroup with weak patterns and shorter active duration. Future research is needed to investigate the biologic processes related to these behavioral phenotypes, including why earlier and robust activity patterns appear protective, and whether modifying disrupted patterns improves outcomes.

Project description:Currently, patients with end-stage lung disease are limited to lung transplantation as their only treatment option. Unfortunately, the lungs available for transplantation are few. Moreover, transplant recipients require life-long immune suppression to tolerate the transplanted lung. A promising alternative therapeutic strategy is decellularization of whole lungs, which permits the isolation of an intact scaffold comprised of innate extracellular matrix (ECM) that can theoretically be recellularized with autologous stem or progenitor cells to yield a functional lung. Nonhuman primates (NHP) provide a highly relevant preclinical model with which to assess the feasibility of recellularized lung scaffolds for human lung transplantation. Our laboratory has successfully accomplished lung decellularization and initial stem cell inoculation of the resulting ECM scaffold in an NHP model. Decellularization of normal adult rhesus macaque lungs as well as the biology of the resulting acellular matrix have been extensively characterized. Acellular NHP matrices retained the anatomical and ultrastructural properties of native lungs with minimal effect on the content, organization, and appearance of ECM components, including collagen types I and IV, laminin, fibronectin, and sulfated glycosaminoglycans (GAG), due to decellularization. Proteomics analysis showed enrichment of ECM proteins in total tissue extracts due to the removal of cells and cellular proteins by decellularization. Cellular DNA was effectively removed after decellularization (?92% reduction), and the remaining nuclear material was found to be highly disorganized, very-low-molecular-weight fragments. Both bone marrow- and adipose-derived mesenchymal stem cells (MSC) attach to the decellularized lung matrix and can be maintained within this environment in vitro, suggesting that these cells may be promising candidates and useful tools for lung regeneration. Analysis of decellularized lung slice cultures to which MSC were seeded showed that the cells attached to the decellularized matrix, elongated, and proliferated in culture. Future investigations will focus on optimizing the recellularization of NHP lung scaffolds toward the goal of regenerating pulmonary tissue. Bringing this technology to eventual human clinical application will provide patients with an alternative therapeutic strategy as well as significantly reduce the demand for transplantable organs and patient wait-list time.

Project description:BackgroundMonitoring salt consumption in children is essential for informing and implementing public health interventions to reduce children's salt intake. However, collection of 24-hour urines, considered as the most reliable approach, can be especially challenging to school children. This study aimed to assess the agreement between 24-hour urine (24hrU) and 24-hour food recall (24hrFR) in: (1) estimating salt intake in children; (2) classifying salt intakes above the recommended upper level set for children, and; (3) estimating change in mean salt intake over time.MethodsThis study utilised data from two cross-sectional surveys of school children aged 8 to 12 years living in the state of Victoria, Australia. A single 24hrU and 24hrFR were collected from each participant. Suspected inaccurate urine collections and implausible energy intakes were excluded based on pre-defined criteria. The agreement between the two methods was assessed using Bland-Altman methodology, the intraclass correlation coefficient (ICC), and the kappa statistic. The difference between the measured change in salt intake over time using 24hrU and 24hrFR was derived using mixed effects linear regression analysis.ResultsA total of 588 participants provided a 24hrU and 24hrFR. Overall, there was no meaningful difference in mean estimated salt intake between the two methods (- 0.2 g/day, 95% CI - 0.5 to 0.1). The Bland-Altman plot showed wide 95% limits of agreement (- 7.2 to 6.8). The ICC between the two methods was 0.13 (95% CI 0.05 to 0.21). There was poor interrater reliability in terms of classifying salt intake above the recommended upper level for children, with an observed agreement of 63% and kappa statistic of 0.11. The change in mean salt intake over time was 0.2 g/day (- 0.4 to 0.7) based on 24hrU, and 0.5 g/day (- 0.0 to 1.1) based on 24hrFR, with a difference-in-differences of 0.4 g/day (- 0.3 to 1.1).Conclusions24hrFR appears to provide a reasonable estimate of mean salt intake as measured by 24hrU in Australian school children. However, similar to previous observations in adults, and of studies exploring other alternative methods for estimating salt intake, 24hrFR is a poor predictor of individual-level salt intake in children.