Reelin is required for class-specific retinogeniculate targeting.

Development of visual system circuitry requires the formation of precise synaptic connections between neurons in the retina and brain. For example, axons from retinal ganglion cells (RGCs) form synapses onto neurons within subnuclei of the lateral geniculate nucleus (LGN) [i.e., the dorsal LGN (dLGN), ventral LGN (vLGN), and intergeniculate leaflet (IGL)]. Distinct classes of RGCs project to these subnuclei: the dLGN is innervated by image-forming RGCs, whereas the vLGN and IGL are innervated by non-image-forming RGCs. To explore potential mechanisms regulating class-specific LGN targeting, we sought to identify differentially expressed targeting molecules in these LGN subnuclei. One candidate targeting molecule enriched in the vLGN and IGL during retinogeniculate circuit formation was the extracellular matrix molecule reelin. Anterograde labeling of RGC axons in mutant mice lacking functional reelin (reln(rl/rl)) revealed reduced patterns of vLGN and IGL innervation and misrouted RGC axons in adjacent non-retino-recipient thalamic nuclei. Using genetic reporter mice, we further demonstrated that mistargeted axons were from non-image-forming, intrinsically photosensitive RGCs (ipRGCs). In contrast to mistargeted ipRGC axons, axons arising from image-forming RGCs and layer VI cortical neurons correctly targeted the dLGN in reln(rl/rl) mutants. Together, these data reveal that reelin is essential for the targeting of LGN subnuclei by functionally distinct classes of RGCs.

Nasal carriage of inducible dormant and community-associated methicillin-resistant Staphylococcus aureus in an ambulatory population of predominantly university students.

BACKGROUND: We studied risk factors for nasal colonization with inducible dormant methicillin-resistant Staphylococcus aureus (ID-MRSA) and community-associated MRSA (CA-MRSA) in a cohort of predominantly university students. METHODS: Nasal surveillance cultures were performed in student health and ambulatory clinics. Molecular features were identified and risk factors for CA-MRSA and ID-MRSA colonization were determined by logistic regression. RESULTS: Of the 1000 participants, 89% (n = 890) were university students. Sixty-four percent were female, 59% Caucasian. The mean age was 23.5 years; 1.6% (n = 16) were CA-MRSA and 1.4% (n = 14) were ID-MRSA colonized. Fifteen (94%) of the CA-MRSA strains were PFGE type IV. pvl (Panton-Valentine leukocidin gene) positivity was 75% in CA-MRSA and 57% in ID-MRSA. ID-MRSA isolates were pulsed-field gel electrophoresis (PFGE) type I, 7%; type II, 14%; type V, 7%; and type IV, 71%. CA-MRSA SCCmec classification was 94% type IV and 6% type V. Risk factors for carriage of CA-MRSA were older age (OR 1.046, p=0.040) and dog ownership (OR 1.450, p=0.019). Single family home (OR 0.040, p=0.007) was a protective factor. There were no significant variables of association found for ID-MRSA colonization. CONCLUSIONS: ID-MRSA/CA-MRSA colonization was low. Most isolates were PFGE types IV and II, pvl-positive and susceptible to several antibiotics. Older age and dog ownership were risk factors for CA-MRSA. Future studies are needed to assess the impact of ID-MRSA carriage.

Trial of universal gloving with emollient-impregnated gloves to promote skin health and prevent the transmission of multidrug-resistant organisms in a surgical intensive care unit.

OBJECTIVE: To compare the efficacy of universal gloving with emollient-impregnated gloves with standard contact precautions for the control of multidrug-resistant organisms (MDROs) and to measure the effect on healthcare workers' (HCWs') hand skin health. DESIGN: Prospective before-after trial. SETTING: An 18-bed surgical intensive care unit. METHODS: During phase 1 (September 2007 through March 2008) standard contact precautions were used. During phase 2 (March 2008 through September 2008) universal gloving with emollient-impregnated gloves was used, and no contact precautions. Patients were screened for vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA). HCW hand hygiene compliance and hand skin health and microbial contamination were assessed. The incidences of device-associated infection and Clostridium difficile infection (CDI) were determined. RESULTS: The rate of compliance with contact precautions (phase 1) was 67%, and the rate of compliance with universal gloving (phase 2) was 78% (P = .01). Hand hygiene compliance was higher during phase 2 than during phase 1 (before patient care, 40% vs 35% of encounters; P = .001; after patient care, 63% vs 51% of encounters; P < .001). No difference was observed in MDRO acquisition. During phases 1 and 2, incidences of device-related infections, in number of infections per 1,000 device-days, were, respectively, 3.7 and 2.6 for bloodstream infection (P = .10), 8.9 and 7.8 for urinary tract infection (P = .10), and 1.0 and 1.1 for ventilator-associated pneumonia (P = .09). The CDI incidence in phase 1 and in phase 2 was, respectively, 2.0 and 1.4 cases per 1,000 patient-days (P = .53). During phase 1, 29% of HCW hand cultures were MRSA positive, compared with 13% during phase 2 (P = .17); during phase 1, 2% of hand cultures were VRE positive, compared with 0 during phase 2 (P = .16). Hand skin health improved during phase 2. CONCLUSIONS: Compared with contact precautions, universal gloving with emollient-impregnated gloves was associated with improved hand hygiene compliance and skin health. No statistically significant change in the rates of device-associated infection, CDI, or patient MDRO acquisition was observed. Universal gloving may be an alternative to contact precautions.