Bolstering gun injury surveillance accuracy using capture-recapture methods.

Using a single source of data, such as police records, or combining data from multiple sources results in an undercount of gun-related injuries. To improve gun-related injury surveillance accuracy by using capture-recapture methods, data were culled from law enforcement, emergency departments, emergency medical services, media, and medical examiner records. The data overlap was operationalized using capture-recapture to generate estimates of uncounted gun incidents. Dependencies between data sources were controlled using log-linear modeling for accurate estimates. New Haven, Connecticut. The study population included subjects injuried/killed from a gun projectile. Incidence was measured using capture-recapture. 49 gun injuries occurred within the defined geography. No single source recorded more than 43 gun-related injuries/deaths. Log-linear modeling estimated the actual number of injuries to be 49.1 (95% CI 49-49.9). Capture-recapture may be less useful in large metropolitan areas that cross state geographical boundaries because of how government agency data are aggregated within each state. No single data source achieves complete gun-related case ascertainment. Log-linear and capture-recapture methods significantly improve gun-related injury estimates.

Sensory neuron signaling to the brain: properties of transmitter release from olfactory nerve terminals.

Olfactory receptor neurons (ORNs) convey sensory information directly to the CNS via conventional glutamatergic synaptic contacts in olfactory bulb glomeruli. To better understand the process by which information contained in the odorant-evoked firing of ORNs is transmitted to the brain, we examined the properties of glutamate release from olfactory nerve (ON) terminals in slices of the rat olfactory bulb. We show that marked paired pulse depression is the same in simultaneously recorded periglomerular and tufted neurons, and that this form of short-term plasticity is attributable to a reduction of glutamate release from ON terminals. We used the progressive blockade of NMDA receptor (NMDAR) EPSCs by MK-801 [(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-10-imine hydrogen maleate] and stationary fluctuation analysis of AMPA receptor (AMPAR) EPSCs to determine the probability of release (P(r)) of ON terminals; both approaches indicated that P(r) is unusually high (>/=0.8). The low-affinity glutamate receptor antagonists gamma-d-glutamylglycine and l-amino-5-phosphonovaleric acid blocked ON-evoked AMPAR- and NMDAR-mediated EPSCs, respectively, to the same extent under conditions of low and high P(r), suggesting that multivesicular release is not a feature of ON terminals. Although release from most synapses exhibits a highly nonlinear dependence on extracellular Ca(2+), we find that the relationship between glutamate release and extracellular Ca(2+) at ON terminals is nearly linear. Our results suggest that ON terminals have specialized features that may contribute to the reliable transmission of sensory information from nose to brain.