Identification of compounds that cause axonal dieback without cytotoxicity in dorsal root ganglia explants and intervertebral disc cells with potential to treat pain via denervation.

Low back pain, knee osteoarthritis, and cancer patients suffer from chronic pain. Aberrant nerve growth into intervertebral disc, knee, and tumors, are common pathologies that lead to these chronic pain conditions. Axonal dieback induced by capsaicin (Caps) denervation has been FDA-approved to treat painful neuropathies and knee osteoarthritis but with short-term efficacy and discomfort. Herein, we propose to evaluate pyridoxine (Pyr), vincristine sulfate (Vcr) and ionomycin (Imy) as axonal dieback compounds for denervation with potential to alleviate pain. Previous literature suggests Pyr, Vcr, and Imy can cause undesired axonal degeneration, but no previous work has evaluated axonal dieback and cytotoxicity on adult rat dorsal root ganglia (DRG) explants. Thus, we performed axonal dieback screening using adult rat DRG explants in vitro with Caps as a positive control and assessed cytotoxicity. Imy inhibited axonal outgrowth and slowed axonal dieback, while Pyr and Vcr at high concentrations produced significant reduction in axon length and robust axonal dieback within three days. DRGs treated with Caps, Vcr, or Imy had increased DRG cytotoxicity compared to matched controls, but overall cytotoxicity was minimal and at least 88% lower compared to lysed DRGs. Pyr did not lead to any DRG cytotoxicity. Further, neither Pyr nor Vcr triggered intervertebral disc cell death or affected cellular metabolic activity after three days of incubation in vitro. Overall, our findings suggest Pyr and Vcr are not toxic to DRGs and intervertebral disc cells, and there is potential for repurposing these compounds for axonal dieback compounds to cause local denervation and alleviate pain.

Type I collagen concentration affects neurite outgrowth of adult rat DRG explants by altering mechanical properties of hydrogels.

Type I collagen is a predominant fibrous protein that makes up the extracellular matrix. Collagen enhances cell attachment and is commonly used in three-dimensional culture systems, to mimic the native extracellular environment, for primary sensory neurons such as dorsal root ganglia (DRG). However, the effects of collagen concentration on adult rat DRG neurite growth have not been assessed in a physiologically relevant, three-dimensional culture. This study focuses on the effects of type I collagen used in a methacrylated hyaluronic acid (MAHA)-laminin-collagen gel (triple gel) on primary adult rat DRG explants in vitro. DRGs were cultured in triple gels, and the neurite lengths and number of support cells were quantified. Increased collagen concentration significantly reduced neurite length but did not affect support cell counts. Mechanical properties, fiber diameter, diffusivity, and mesh size of the triple gels with varying collagen concentration were characterized to further understand the effects of type I collagen on hydrogel property that may affect adult rat DRG explants. Gel stiffness significantly increased as collagen concentration increased and is correlated to DRG neurite length. Collagen concentration also significantly impacted fiber diameter but there was no correlation with DRG neurite length. Increasing collagen concentration had no significant effect on mesh size and diffusivity of the hydrogel. These data suggest that increasing type I collagen minimizes adult rat DRG explant growth in vitro while raising gel stiffness. This knowledge can help develop more robust 3D culture platforms to study sensory neuron growth and design biomaterials for nerve regeneration applications.

Correction to: an automatic water detection approach using Landsat 8 OLI and Google earth engine cloud computing to map lakes and reservoirs in New Zealand.

In the published article:"An automatic water detection approach using Landsat 8 OLI and Google Earth Engine cloud computing to map lakes and reservoirs in New Zealand", the Acknowledgements was published incorrectly and funding statement was missing.

An automatic water detection approach using Landsat 8 OLI and Google Earth Engine cloud computing to map lakes and reservoirs in New Zealand.

Monitoring water surface dynamics is essential for the management of lakes and reservoirs, especially those are intensively impacted by human exploitation and climatic variation. Although modern satellites have provided a superior solution over traditional methods in monitoring water surfaces, manually downloading and processing imagery associated with large study areas or long-time scales are time-consuming. The Google Earth Engine (GEE) platform provides a promising solution for this type of "big data" problems when it is combined with the automatic water extraction index (AWEI) to delineate multi-temporal water pixels from other forms of land use/land cover. The aim of this study is to assess the performance of a completely automatic water extraction framework by combining AWEI, GEE, and Landsat 8 OLI data over the period 2014-2018 in the case study of New Zealand. The overall accuracy (OA) of 0.85 proved the good performance of this combination. Therefore, the framework developed in this research can be used for lake and reservoir monitoring and assessment in the future. We also found that despite the temporal variability of climate during the period 2014-2018, the spatial areas of most of the lakes (3840) in the country remained the same at around 3742 km2. Image fusion or aerial photos can be employed to check the areal variation of the lakes at a finer scale.

Survey of Knowledge, Beliefs, and Behaviors of Migrant Vietnamese Parents Regarding Young Children's Oral Health.

Purpose: The purpose of this study was to investigate the oral health knowledge, beliefs, and behaviors of migrant Vietnamese parents of 1-5 year-olds in San Jose, California.Method: A verbally-administered survey was conducted with a convenience sample of 45 Vietnamese parents recruited at San Jose public libraries. Following preliminary screening, written informed consent was obtained from eligible individuals. A pre-tested, structured 94-item questionnaire was used to collect information regarding parent demographics, and the parent's knowledge, beliefs, and behaviors about children's oral health. Simple descriptive statistics were used to analyze the data.Results: Vietnamese parents acknowledged a number of basic concepts regarding early childhood caries (ECC), such as influences of sugar consumption, oral hygiene, and bottle use. Unlike other groups, they reported some familiarity with the role of bacteria in caries etiology. Oral health knowledge and beliefs, however, were not reflected in parental oral health behaviors such as supervision of children's brushing. Knowledge about the preventive role of fluoride was limited and varied among the population. Parental knowledge and behaviors did not vary by education level or length of residence in US.Conclusion: Vietnamese parents demonstrated reasonably good oral health knowledge, but poor behavioral guidance of their children's oral health, indicating the need for continued parental education emphasizing age-appropriate oral care and the preventative role of fluoride.