High-sensitivity rod photoreceptor input to the blue-yellow color opponent pathway in macaque retina.

Small bistratified cells (SBCs) in the primate retina carry a major blue-yellow opponent signal to the brain. We found that SBCs also carry signals from rod photoreceptors, with the same sign as S cone input. SBCs exhibited robust responses under low scotopic conditions. Physiological and anatomical experiments indicated that this rod input arose from the AII amacrine cell-mediated rod pathway. Rod and cone signals were both present in SBCs at mesopic light levels. These findings have three implications. First, more retinal circuits may multiplex rod and cone signals than were previously thought to, efficiently exploiting the limited number of optic nerve fibers. Second, signals from AII amacrine cells may diverge to most or all of the approximately 20 retinal ganglion cell types in the peripheral primate retina. Third, rod input to SBCs may be the substrate for behavioral biases toward perception of blue at mesopic light levels.

Secondary data analysis of lead screening compliance in high-risk children

Introduction. Despite the ban of lead-containing gasoline and paint, childhood lead poisoning remains a public health issue. Furthermore, a Medicaid-eligible child is 8 times more likely to have an elevated blood lead level (EBLL) than a non-Medicaid child, which is the primary reason for the early detection lead screening mandate for ages 12 and 24 months among the Medicaid population. Based on field observations, there was evidence that suggested a screening compliance issue. Objective. The purpose of this study was to analyze blood lead screening compliance in previously lead poisoned Medicaid children and test for an association between timely lead screening and timely childhood immunizations. The mean months between follow-up tests were also examined for a significant difference between the non-compliant and compliant lead screened children. Methods. Access to the surveillance data of all childhood lead poisoned cases in Bexar County was granted by the San Antonio Metropolitan Health District. A database was constructed and analyzed using descriptive statistics, logistic regression methods and non-parametric tests. Lead screening at 12 months of age was analyzed separately from lead screening at 24 months. The small portion of the population who were also related were included in one analysis and removed from a second analysis to check for significance. Gender, ethnicity, age of home, and having a sibling with an EBLL were ruled out as confounders for the association tests but ethnicity and age of home were adjusted in the nonparametric tests. Results. There was a strong significant association between lead screening compliance at 12 months and childhood immunization compliance, with or without including related children (p<0.00). However, there was no significant association between the two variables at the age of 24 months. Furthermore, there was no significant difference between the median of the mean months of follow-up blood tests among the non-compliant and compliant lead screened population for at the 12 month screening group but there was a significant difference at the 24 month screening group (p<0.01). Discussion. Descriptive statistics showed that 61% and 56% of the previously lead poisoned Medicaid population did not receive their 12 and 24 month mandated lead screening on time, respectively. This suggests that their elevated blood lead level may have been diagnosed earlier in their childhood. Furthermore, a child who is compliant with their lead screening at 12 months of age is 2.36 times more likely to also receive their childhood immunizations on time compared to a child who was not compliant with their 12 month screening. Even though there was no statistical significant association found for the 24 month group, the public health significance of a screening compliance issue is no less important. The Texas Medicaid program needs to enforce lead screening compliance because it is evident that there has been no monitoring system in place. Further recommendations include a need for an increased focus on parental education and the importance of taking their children for wellness exams on time.^

Maternal Role & High-Risk Pregnancy Experience with Antepartum Hospitalization

Purpose. The focus of maternal role development, historically, has been on the tasks and processes during pregnancy as they relate to postpartum role transition. The purpose of this study was to investigate how women hospitalized with high-risk pregnancy cognitively construct pregnancy and impending motherhood. ^ Design. The study employed a triangulation design using a convergence model with a dominant focused ethnographic approach. ^ Setting. The antepartum units of two tertiary care centers in a large metropolitan city in southeast Texas. ^ Sample. Data saturation was determined with thirteen (13) primigravid women who had been hospitalized more than 72 hours with preterm labor (PTL) or preterm premature rupture of membranes (PPROM) who subsequently delivered seventeen (17) infants which included 4 sets of twins. ^ Methods. Open-ended, semi-structured interviews and field work were used to explore the development of maternal role in this population. After collecting descriptive data, long individual interviews were conducted and the Prenatal Self Evaluation Questionnaire (PSEQ), an instrument to measure prenatal adaptation to pregnancy, was administered. The interview focused on exploring the woman's experiences of pregnancy and impending motherhood while hospitalized. Interview data and field notes were coded and analyzed using qualitative thematic analytic techniques. The PSEQ was scored and the findings of the qualitative data and PSEQ data were compared. ^ Findings. Thematic analysis of the qualitative data provided an understanding of the cognitive process that occurs as the pregnant woman builds a relationship with the fetus. Thematic analysis resulted in a conceptual model with two complementary components that occur throughout the pregnancy: Establishing a Relationship and Dynamic Equilibrium. Establishing a Relationship includes subthemes of: Courting, Building a Connection, and Engagement. Dynamic equilibrium is the balance between expectations and reality and exists regardless of pregnancy complications. The negotiation of this potential imbalance is triggered by uncertainty, loss of autonomy and control, and isolation and is exacerbated by the high-risk pregnancy and subsequent hospitalization. These triggers can serve as obstacles to maternal role development, but may be mediated by external support from friends and family or health care providers. Support from others may come in the form of anticipatory guidance, presence, or activities that promote self-agency. PSEQ scores were similar to previous reports, but due to the small sample, scores were used primarily for comparison to qualitative data. The qualitative findings were congruent with the PSEQ findings in all of the subscales except in the concern for the well-being of the baby. Interview reports included comments demonstrating significant concern for the well-being of the infant, yet the related subscale did not demonstrate such concern. ^ Conclusions. An understanding of the cognitive process involved in establishing a relationship with the developing fetus related to impending motherhood and the importance of dynamic equilibrium can allow healthcare providers and those who interact with pregnant women to support development of the maternal role and anticipate those barriers that may impede that process. Findings from this study identify those triggers and mediators that influence development of the maternal role and suggest potential intervening strategies for those involved in the care of childbearing families. ^

A case-comparison interview study of brain tumors and employment in occupations with presumed electric and magnetic field exposures

Results from epidemiologic studies suggest that persons working in occupations with presumed electric and magnetic field (EMF) exposures are at increased risk of brain cancer. This study utilized data from a completed, population-based, interview case-control study of central nervous system (CNS) tumors and employment in the petrochemical industry to test the hypothesis that employment in EMF-related occupations increases CNS tumor risk. A total of 375 male residents of the Texas-Louisiana Gulf Coast Area, age 20 to 79, with primary neuroglial CNS tumors diagnosed during the period 1980-84 were identified. A population-based comparison group of 450 age, race and geographically matched males was selected. Occupational histories and potential risk factor data were collected via personal interviews with study subjects or their next-of-kin.^ Adjusted odds ratios were less than 1.0 for persons ever employed in an electrical occupation (OR = 0.65; 95% CI = 0.40-1.09) or whose usual occupation was electrical (OR = 0.76; 95% CI = 0.33-1.73). Relative risk estimates did not increase significantly as time since first employment or duration of employment increased. Examination of CNS tumor risk by high (OR = 0.80), medium (OR = 0.88) and low (OR = 0.45) exposure categories for persons whose usual occupation was electrical did not indicate a dose-response pattern. In addition, the mean age of exposed cases was not significantly younger than that for unexposed cases. Analysis of risk by probability of exposure to EMFs showed non-significant elevations in the adjusted odds ratio for definite exposed workers defined by their usual occupation (OR = 1.78; 95% CI = 0.70-4.51) and ever/never employed status (OR = 1.54; 95% CI = 0.17-4.91).^ These findings suggest that employment in occupations with presumed EMF exposures does not increase CNS tumor risk as was suggested by previous investigations. The results of this study also do not support the EMF-tumor promotion hypothesis. ^