Hypertonic Dextrose Stimulates Chondrogenic Cells to Deposit Collagen and Proliferate.

OBJECTIVE: Hypertonic dextrose (HD) injections (prolotherapy) for osteoarthritis are reported to reduce pain. Cartilage regeneration is hypothesized as a mechanism. This in vitro study identifies an HD concentration that stimulates chondrogenic cells to increase metabolic activity and assesses whether this concentration affects collagen deposition and proliferation. DESIGN: ATDC5 chondrogenic cells were cultured in normoglycemic DMEM/F12 medium, treated with concentrations of HD (4-400 mM), and assessed with PrestoBlue. Advanced light microscopy was used to conduct live imaging of collagen deposition through second harmonic generation microscopy (SHG) and proliferation via 2-photon excitation microscopy. Proliferation was additionally assessed with hemocytometer counts. RESULTS: A linear regression model found that, relative to the 4 mM baseline control, cells treated with 200 mM had a higher mean absorbance (P = 0.023) and cells treated with 250 mM were trending toward a higher mean absorbance (P = 0.076). Polynomial regression interpolated 240 mM as producing the highest average absorbance. Hemocytometer counts validated 250 mM as stimulating proliferation compared with the 4 mM control (P < 0.01). A concentration of 250 mM HD led to an increase in collagen deposition compared with that observed in control (P < 0.05). This HD concentration also led to increases in proliferation of ATDC5 cells relative to that of control (P < 0.001). CONCLUSIONS: A 250 mM HD solution appears to be associated with increased metabolic activity of chondrocytes, increased collagen deposition, and increased chondrocyte proliferation. These results support clinical prolotherapy research suggesting that intra-articular HD joint injections reduce knee pain. Further study of HD and cellular processes is warranted.

The COVID Connection: Pandemic Anxiety, COVID-19 Comprehension, and Digital Confidence.

This article presents logistic models examining how pandemic anxiety and COVID-19 comprehension vary with digital confidence among adults in the United States during the first wave of the pandemic. As we demonstrate statistically with a nationally representative data set, the digitally confident have lower probability of experiencing physical manifestations of pandemic anxiety and higher probability of adequately comprehending critical information on COVID-19. The effects of digital confidence on both pandemic anxiety and COVID-19 comprehension persist, even after a broad range of potentially confounding factors are taken into account, including sociodemographic factors such as age, gender, race/ethnicity, metropolitan status, and partner status. They also remain discernable after the introduction of general anxiety, as well as income and education. These results offer evidence that the digitally disadvantaged experience greater vulnerability to the secondary effects of the pandemic in the form of increased somatized stress and decreased COVID-19 comprehension. Going forward, future research and policy must make an effort to address digital confidence and digital inequality writ large as crucial factors mediating individuals' responses to the pandemic and future crises.

Cascading Crises: Society in the Age of COVID-19.

The tsunami of change triggered by the COVID-19 pandemic has transformed society in a series of cascading crises. Unlike disasters that are more temporarily and spatially bounded, the pandemic has continued to expand across time and space for over a year, leaving an unusually broad range of second-order and third-order harms in its wake. Globally, the unusual conditions of the pandemic-unlike other crises-have impacted almost every facet of our lives. The pandemic has deepened existing inequalities and created new vulnerabilities related to social isolation, incarceration, involuntary exclusion from the labor market, diminished economic opportunity, life-and-death risk in the workplace, and a host of emergent digital, emotional, and economic divides. In tandem, many less advantaged individuals and groups have suffered disproportionate hardship related to the pandemic in the form of fear and anxiety, exposure to misinformation, and the effects of the politicization of the crisis. Many of these phenomena will have a long tail that we are only beginning to understand. Nonetheless, the research also offers evidence of resilience on several fronts including nimble organizational response, emergent communication practices, spontaneous solidarity, and the power of hope. While we do not know what the post COVID-19 world will look like, the scholarship here tells us that the virus has not exhausted society's adaptive potential.