IMPORTANCE In late December 2019, an outbreak caused by a novel severe acute respiratory syndrome coronavirus 2 emerged in Wuhan, China. Data on the clinical characteristics and outcomes of infected patients in urban communities in the US are limited. OBJECTIVES To describe the clinical characteristics and outcomes of patients with coronavirus disease 2019 (COVID-19) and to perform a comparative analysis of hospitalized and ambulatory patient populations. DESIGN, SETTING, AND PARTICIPANTS This study is a case series of 463 consecutive patients with COVID-19 evaluated at Henry Ford Health System in metropolitan Detroit, Michigan, from March 9 to March 27, 2020. Data analysis was performed from March to April 2020. EXPOSURE Laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection. MAIN OUTCOMES AND MEASURES Demographic data, underlying comorbidities, clinical presentation, complications, treatment, and outcomes were collected.RESULTS Of 463 patients with COVID-19 (mean [SD] age, 57.5 [16.8] years), 259 (55.9%) were female, and 334 (72.1%) were African American. Most patients (435 [94.0%]) had at least 1 comorbidity, including hypertension (295 patients [63.7%]), chronic kidney disease (182 patients [39.3%]), and diabetes (178 patients [38.4%]). Common symptoms at presentation were cough (347 patients [74.9%]), fever (315 patients [68.0%]), and dyspnea (282 patients [60.9%]). Three hundred fifty-five patients (76.7%) were hospitalized; 141 (39.7%) required intensive care unit management and 114 (80.8%) of those patients required invasive mechanical ventilation. Male sex (odds ratio [OR], 2.0; 95% CI, 1.3-3.2; P = .001), severe obesity (OR, 2.0; 95% CI, 1.4-3.6; P = .02), and chronic kidney disease (OR, 2.0; 95% CI, 1.3-3.3; P = .006) were independently associated with intensive care unit admission. Patients admitted to the intensive care unit had longer length of stay and higher incidence of respiratory failure and acute respiratory distress syndrome requiring invasive mechanical ventilation, acute kidney injury requiring dialysis, shock, and mortality (57 patients [40.4%] vs 15 patients [7.0%]) compared with patients in the general practice unit. Twenty-nine (11.2%) of those discharged from the hospital were readmitted and, overall, 20.0% died within 30

Intrinsically photosensitive retinal ganglion cells (ipRGCs) are inner retinal photoreceptors that mediate non-image-forming visual functions, e.g. pupillary constriction, regulation of pineal melatonin release, and circadian photoentrainment. Five types of ipRGCs were recently discovered in mouse, but whether they exist in other mammals remained unknown. We report that the rat also has five types of ipRGCs, whose morphologies match those of mouse ipRGCs; this is the first demonstration of all five cell types in a non-mouse species. Through immunostaining and λmax measurements, we showed that melanopsin is likely the photopigment of all rat ipRGCs. The various cell types exhibited diverse spontaneous spike rates, with the M1 type spiking the least and M4 spiking the most, just like we had observed for their mouse counterparts. Also similar to mouse, all ipRGCs in rat generated not only sluggish intrinsic photoresponses but also fast, synaptically driven ones. However, we noticed two significant differences between these species. First, whereas we learned previously that all mouse ipRGCs had equally sustained synaptic light responses, rat M1 cells’ synaptic photoresponses were far more transient than those of M2–M5. Since M1 cells provide all input to the circadian clock, this rat-versus-mouse discrepancy could explain the difference in photoentrainment threshold between mouse and other species. Second, rat ipRGCs’ melanopsin-based spiking photoresponses could be classified into three varieties, but only two were discerned for mouse ipRGCs. This correlation of spiking photoresponses with cell types will help researchers classify ipRGCs in multielectrode-array (MEA) spike recordings.

SUMMARY Retinal neurons exhibit sustained vs. transient light responses, which are thought to encode low- and high-frequency stimuli respectively. This dichotomy has been recognized since the earliest intracellular recordings from the 1960s, but the underlying mechanisms are not yet fully understood. We report that in the ganglion cell layer of rat retinas, all spiking amacrine interneurons with sustained ON photoresponses receive gap-junction input from intrinsically photosensitive retinal ganglion cells (ipRGCs), recently discovered photoreceptors that specialize in prolonged irradiance detection. We have identified three morphological varieties of such ipRGC-driven displaced amacrine cells: 1) monostratified cells with dendrites terminating exclusively in sublamina S5 of the inner plexiform layer; 2) bistratified cells with dendrites in both S1 and S5; and 3) polyaxonal cells with dendrites and axons stratifying in S5. Most of these amacrine cells are wide-field, although some are medium-field. The three classes respond to light differently, suggesting they probably perform diverse functions. These results demonstrate that ipRGCs are a major source of tonic visual information within the retina and exert widespread intraretinal influence. They also add to recent evidence that ganglion cells signal not only to the brain.