"Las Dos Cosas," or Why Mexican American Mothers Breast-Feed, But Not for Long.

OBJECTIVES: To determine why mothers in El Paso, Texas, choose to breast-feed but not exclusively and why breast-feeding duration is short. METHODS: This was a cross-sectional observational study of 300, mostly Mexican American, low-income mothers delivering at a county hospital who answered questions about breast-feeding and formula feeding, sociodemographics, and health habits. RESULTS: Most mothers (92.6%) in our study initiated breast-feeding, but only 20.3% breast-fed exclusively at the time of hospital discharge. Most mothers (73%) self-identified as Mexicans or Mexican Americans living on the border of the United States and Mexico. Mothers in our study chose to breast-feed if they decided to breast-feed during pregnancy, had breast-fed a previous child, had support from a female relative, and had attended college. Distinctively, most mothers in our study chose "las dos cosas" or to breast-feed and formula feed together early after birth. Acculturation failed to explain the breast-feeding decisions. CONCLUSIONS: Mexican American mothers who decided to breast-feed during pregnancy, breast-fed another child, attended college, and enlist a female relative's breast-feeding help were more likely to choose breast-feeding exclusively. Most Mexican American low-income mothers in our study chose "las dos cosas."

Crystal structure of the DNA-recognition component of the bacterial virus Sf6 genome-packaging machine.

In herpesviruses and many bacterial viruses, genome-packaging is a precisely mediated process fulfilled by a virally encoded molecular machine called terminase that consists of two protein components: A DNA-recognition component that defines the specificity for packaged DNA, and a catalytic component that provides energy for the packaging reaction by hydrolyzing ATP. The terminase docks onto the portal protein complex embedded in a single vertex of a preformed viral protein shell called procapsid, and pumps the viral DNA into the procapsid through a conduit formed by the portal. Here we report the 1.65 A resolution structure of the DNA-recognition component gp1 of the Shigella bacteriophage Sf6 genome-packaging machine. The structure reveals a ring-like octamer formed by interweaved protein monomers with a highly extended fold, embracing a tunnel through which DNA may be translocated. The N-terminal DNA-binding domains form the peripheral appendages surrounding the octamer. The central domain contributes to oligomerization through interactions of bundled helices. The C-terminal domain forms a barrel with parallel beta-strands. The structure reveals a common scheme for oligomerization of terminase DNA-recognition components, and provides insights into the role of gp1 in formation of the packaging-competent terminase complex and assembly of the terminase with the portal, in which ring-like protein oligomers stack together to form a continuous channel for viral DNA translocation.

The Perfect Storm: A Case of Rapid-Onset Obesity With Hypoventilation, Hypothalamic, Autonomic Dysregulation, Neuroendocrine Tumor (ROHHADNET) With Heart Failure, Narcolepsy, and a Rare Location of a Pelvic Neuroendocrine Tumor.

Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) syndrome is a rare disease of concurrent respiratory dysfunction and autonomic dysregulation with endocrine abnormalities. ROHHADNET includes ROHHAD plus coexisting neuroendocrine tumors (NETs). We describe an eight-year-old boy, who originally presented at four years of age with rapid weight gain and hyperhidrosis and who developed mild obstructive sleep apnea (OSA). His clinical course was eventually complicated by hypoxic respiratory failure requiring admission to the pediatric intensive care unit (PICU). Echocardiogram at that time demonstrated dilated cardiomyopathy left ventricular ejection fraction (LVEF) of 28% at time of admission. His respiratory failure persisted despite average volume-assured pressure support (AVAPS) around the clock leading to tracheostomy placement for cardiopulmonary support. He also demonstrated autonomic instability with multiple pituitary hormone deficiencies. Computed tomography (CT) imaging of the abdomen and pelvis demonstrated a presacral soft tissue mass consistent with a tumor of neural crest origin. Daytime somnolence and confusion progressed and a low cerebrospinal fluid hypocretin level revealed a diagnosis of narcolepsy type 1.

Integrated assessment of behavioral and environmental risk factors for Lyme disease infection on Block Island, Rhode Island.

Peridomestic exposure to Borrelia burgdorferi-infected Ixodes scapularis nymphs is considered the dominant means of infection with black-legged tick-borne pathogens in the eastern United States. Population level studies have detected a positive association between the density of infected nymphs and Lyme disease incidence. At a finer spatial scale within endemic communities, studies have focused on individual level risk behaviors, without accounting for differences in peridomestic nymphal density. This study simultaneously assessed the influence of peridomestic tick exposure risk and human behavior risk factors for Lyme disease infection on Block Island, Rhode Island. Tick exposure risk on Block Island properties was estimated using remotely sensed landscape metrics that strongly correlated with tick density at the individual property level. Behavioral risk factors and Lyme disease serology were assessed using a longitudinal serosurvey study. Significant factors associated with Lyme disease positive serology included one or more self-reported previous Lyme disease episodes, wearing protective clothing during outdoor activities, the average number of hours spent daily in tick habitat, the subject's age and the density of shrub edges on the subject's property. The best fit multivariate model included previous Lyme diagnoses and age. The strength of this association with previous Lyme disease suggests that the same sector of the population tends to be repeatedly infected. The second best multivariate model included a combination of environmental and behavioral factors, namely hours spent in vegetation, subject's age, shrub edge density (increase risk) and wearing protective clothing (decrease risk). Our findings highlight the importance of concurrent evaluation of both environmental and behavioral factors to design interventions to reduce the risk of tick-borne infections.