Accessing hemodialysis clinics during the COVID-19 pandemic.

Transportation is a key element of access to healthcare. The COVID-19 pandemic posed unique and unforeseen challenges to patients receiving hemodialysis who rely on three times weekly transportation to receive their life-saving treatments, but there is little data on the problems they faced. This study explores the attitudes, fears, and concerns of hemodialysis patients during the pandemic with a focus on their travel to/from dialysis treatments. A mixed methods travel survey was distributed to hemodialysis patients from three urban centers in Montréal, Canada, during the pandemic (n = 43). The survey included closed questions that were analysed through descriptive statistics as well as open-ended questions that were assessed through thematic analysis. Descriptive statistics show that hemodialysis patients are more fearful of contracting COVID-19 in transit than they are at the treatment center. Patients taking paratransit, public transportation, and taxis are more fearful of COVID-19 while traveling than those who drive, who are driven, or who walk to the clinic. In the open-ended questions, patients reported struggling with confusing COVID-19 protocols in public transport, including conflicting information on whether paratransit taxis allowed one or multiple passengers. Paratransit was the most used travel mode to access treatment (n = 30), with problems identified in the open-ended questions, such as long and unreliable pickup windows, and extended travel times. To limit COVID-19 exposure and stress for paratransit users, agencies should consider sitting one patient per paratransit taxi, clearly communicating COVID-19 protocols online and in the vehicles, and tracking vehicles for more efficient pickups.

Possible sources of dye-related signal correlation bias in two-color DNA microarray assays.

DNA microarray analyses commonly use two spectrally distinct fluorescent labels to simultaneously compare different mRNA pools. Signal correlation bias currently limits accepted resolution to twofold changes in gene expression. This bias was investigated by (i) examining fluorescence and absorption spectra and changes in relative fluorescence of DNAs labeled with the Cy3, Cy5, Alexa Fluor 555, and Alexa Fluor 647 dyes and by (ii) using homotypic hybridization assays to compare the Cy dye pair with the Alexa Fluor dye pair. Cy3 or Cy5 dye-labeled DNA exhibited reduced fluorescence and absorption anomalies that were eliminated by nuclease treatment, consistent with fluorescence quenching that arises from dye-dye or dye-DNA-dye interactions. Alexa Fluor 555 and Alexa Fluor 647 dye-labeled DNA exhibited little or no such anomalies. In microarray hybridization, the Alexa Fluor dye pair provided higher signal correlation coefficients (R2) than did the Cy dye pair; at the 95% prediction level, a 1.3-fold change in gene expression was significant using the Alexa Fluor dye pair. Lowered signal correlation of the Cy dye pair was associated with high variance in Cy5 dye signals. These results indicate that fluorescence quenching may be a source of signal bias associated with the Cy dye pair.