Dendritic and parallel processing of visual threats in the retina control defensive responses

Approaching predators cast expanding shadows (i.e., looming) that elicit innate defensive responses in most animals. Where looming is first detected and how critical parameters of predatory approaches are extracted are unclear. In mice, we identify a retinal interneuron (the VG3 amacrine cell) that responds robustly to looming, but not to related forms of motion. Looming-sensitive calcium transients are restricted to a specific layer of the VG3 dendrite arbor, which provides glutamatergic input to two ganglion cells (W3 and OFFα). These projection neurons combine shared excitation with dissimilar inhibition to signal approach onset and speed, respectively. Removal of VG3 amacrine cells reduces the excitation of W3 and OFFα ganglion cells and diminishes defensive responses of mice to looming without affecting other visual behaviors. Thus, the dendrites of a retinal interneuron detect visual threats, divergent circuits downstream extract critical threat parameters, and these retinal computations initiate an innate survival behavior.

Metabolic syndrome delays HBeAg seroclearance in Chinese patients with hepatitis B

BACKGROUND

Delayed hepatitis B e antigen (HBeAg) seroclearance increases the risk of cirrhosis and hepatocellular carcinoma (HCC). The effect of metabolic syndrome (MetS) on HBeAg seroclearance in chronic hepatitis B (CHB) patients remains unclear.

AIMS

To examine the effect of MetS on HBeAg seroclearance.

METHODS

A prospective cohort of 413 treatment-naïve HBeAg-positive CHB patients from 2005 to 2012 was studied. Clinical, virological and histological parameters were evaluated. The patients were classified into three groups according to the metabolic characteristics; normal, pre-MetS and MetS based on the International Diabetes Federation criteria. The primary outcome was age at HBeAg seroclearance.

RESULTS

The overall HBeAg seroclearance rate was 11.4% per annum during 19 351 patient-months of follow-up with no difference in HBeAg seroclearance rates between 162 treatment-free and 251 patients receiving nucleos(t)ide analogues. Patients with pre-MetS and MetS were older when HBeAg seroclearance occurred (44 ± 12 and 53 ± 7 years, respectively) than the normal patients (37 ± 9 years, all P < 0.01). Patients with pre-MetS and MetS had more advanced liver fibrosis (33.0% and 53.1%, respectively) than the normal patients (18.4%, all P < 0.05). By the age of 50, 59.3% of the metabolic normal patients, 42.1% of the pre-MetS and 18.7% of the MetS patients had achieved HBeAg seroclearance (all P < 0.05, except P = 0.07 for pre-MetS vs. MetS). In multivariate analysis, MetS and type II diabetes at baseline were predictors of delayed HBeAg seroclearance after adjusting for viral load, anti-viral therapy and necroinflammatiom.

CONCLUSION

Chinese patients with chronic hepatitis B and with pre-metabolic syndrome or metabolic syndrome have delayed HBeAg seroclearance.