Stainable hepatic iron in 341 African American adults at coroner/medical examiner autopsy

Background  

Results of previous autopsy studies indicate that increased hepatic iron stores or hepatic iron overload is common in African Americans dying in hospitals, but there are no reports of hepatic iron content in other cohorts of African Americans.     

Age-dependent DNA methylation changes in the ITGAL (CD11a) promoter

DNA methylation patterns change with age in a complex fashion, typically with an overall decrease in genomic deoxymethylcytosine (d(m)C) content, but with local increases in some promoters that contain GC-rich sequences known as CpG islands. While the consequences of age-dependent CpG island methylation have recently been studied in organs such as the colon, less is known about the functional significance of the progressive hypomethylation of promoters lacking CpG islands, and the significance of age-dependent changes in T cell DNA methylation is completely unexplored. We asked if age-dependent DNA hypomethylation might contribute to overexpression of the T cell ITGAL gene, which encodes CD11a, a subunit of LFA-1. CD11a mRNA increased with age as well as with experimentally induced DNA hypomethylation. This increase correlated with hypomethylation of sequences flanking the ITGAL promoter in vitro and in aging. 'Patch' methylation of the region suppressed promoter function. DNA methyltransferases 1 and 3a also decreased with aging. These results indicate that hypomethylation of regions flanking the ITGAL promoter may increase CD11a expression, and suggest that age-dependent hypomethylation of promoters lacking CpG islands, perhaps due to decreased DNA methyltransferase expression, may be one mechanism contributing to increased T cell gene expression with aging.     

Genioglossal hypoglossal motoneurons contact substance P-like immunoreactive nerve terminals in the cat: a dual labeling electron microscopic study

This study investigated the synaptic interactions between hypoglossal motoneurons that project to the genioglossus muscle and substance P (SP) containing immunoreactive nerve terminals. Cholera toxin B conjugated to horseradish peroxidase (CTB-HRP) was injected into the right half of the genioglossus muscle in four anesthetized cats. Two days later, the animals were perfused with acrolein fixative. Tetramethylbenzidine (TMB) was the chromogen used to detect retrogradely labeled cells containing CTB-HRP. The tissues were then processed for immunocytochemisty using an antiserum raised against SP with diaminobenzidine (DAB) as the chromogen. At the light microscopic level, labeled cells were observed primarily ipsilaterally in ventral and ventrolateral subdivisions of the hypoglossal nucleus. The majority of these labeled cells were observed at the level of the area postrema. At the electron microscopic level, SP-like immunoreactive nerve terminals formed synaptic contacts with retrogradely labeled dendrites and perikarya. Nineteen percent of the terminals that contacted retrogradely labeled cells contained SP. These are the first ultrastructural studies demonstrating synaptic interactions between protruder hypoglossal motoneurons and SP terminals. These studies demonstrate that hypoglossal motoneurons which innervate the major protruder muscle of the tongue, the genioglossus muscle, may be modulated by SP. Thus, SP may play a role in the control of protrusive movements of the tongue acting via neurokinin receptors.