Cone inputs to simple and complex cells in V1 of awake macaque

Rules by which V1 neurons combine signals originating in the cone photoreceptors are poorly understood. We measured cone inputs to V1 neurons in awake, fixating monkeys with white-noise analysis techniques that reveal properties of light responses not revealed by purely linear models used in previous studies. Simple cells were studied by spike-triggered averaging that is robust to static nonlinearities in spike generation. This analysis revealed, among heterogeneously tuned neurons, two relatively discrete categories: one with opponent L- and M-cone weights and another with nonopponent cone weights. Complex cells were studied by spike-triggered covariance, which identifies features in the stimulus sequence that trigger spikes in neurons with receptive fields containing multiple linear subunits that combine nonlinearly. All complex cells responded to nonopponent stimulus modulations. Although some complex cells responded to cone-opponent stimulus modulations too, none exhibited the pure opponent sensitivity observed in many simple cells. These results extend the findings on distinctions between simple and complex cell chromatic tuning observed in previous studies in anesthetized monkeys.     

Bactericidal/Permeability-Increasing Protein Inhibits Growth of a Strain of Acholeplasma laidlawii and L Forms of the Gram-Positive Bacteria Staphylococcus aureus and Streptococcus pyogenes

Bactericidal/permeability-increasing protein (BPI) inhibited growth of cell wall-deficient Acholeplasma laidlawii and L forms of certain strains of Staphylococcus aureus and Streptococcus pyogenes. However, the same strains of S. aureus and S. pyogenes with intact cell walls were not susceptible to the growth-inhibitory effects of BPI.     

Mental Health Factors in the Utilization of Pediatric Primary Care

The relationship of mental health factors to use of pediatric medical care in a 12-month period is examined using cross-sectional and prospective data from a community-based cohort of children (aged 4–8 years at baseline) and their families. Results from this study demonstrate that mother's self-reported mental health is statistically significantly related to the number of pediatric visits. In the cross-sectional analysis, the effect of mothers's mental health on children with 5 or more pediatric visits is moderated by poverty and mothers with depressive symptoms are much more likely than those without such symptoms to have children who are very high service users (10 visits or more). In the longitudinal analysis, an inconsistent pattern of mothers' mental health problems over a 24-month period increases the likelihood of high use in the third year and the persistence of maternal mental health problems increases the likelihood of very high use.     

Intensive Intervention Improves Primary Care Follow-up for Uninsured Emergency Department Patients

Objectives: To test an intervention designed to improve primary care use and decrease emergency department (ED) utilization for uninsured patients using the ED. Methods: Using a randomized design, an intensive case‐management intervention was tested with patients identified at a Level 1 urban trauma center from April 2002 through July 2002. Following assessment in the ED, six‐month follow‐up data were gathered from four primary care sites (two Federally Qualified Health Centers, two hospital outpatient clinics) and two area hospitals. Eligible participants were uninsured, were at least 18 years of age, and did not have a regular primary care provider. Of 281 patients approached, 273 (97.2%) agreed to participate. After 42 patients were eliminated following enrollment due to ineligibility, there were 121 intervention and 109 comparison subjects. Health Promotion Advocates (HPAs) in the ED gathered information from all study participants. On intervention shifts, HPAs assisted patients in choosing a primary care provider and faxed all information to a case worker at the selected site. Case managers attempted to contact patients and schedule appointments. On comparison shifts, patients received care as usual. Primary care contact in 60 days and subsequent ED visits in six months post‐ED assessment were the main outcome measures. Results: Intervention subjects were more likely to have a primary care contact (51.2% vs. 13.8%, p < 0.0001). There was no statistically significant difference between groups in either number of inpatient admissions or postintervention ED visits, although postintervention ED visits for the intervention group were less expensive. Conclusions: This project has demonstrated that it is possible to improve primary care follow‐up for uninsured ED patients.