Effects of aging on the novelty P3 during attend and ignore oddball tasks

The effects of attention were assessed on novelty P3 amplitude and scalp distribution elicited by environmental sounds in young and elderly volunteers who participated in either actively attended or ignored oddball conditions. For the young, novelty P3 amplitude decreased with time on task during both attend and ignore sequences. Amplitude decrements were greatest at frontal sites during the attend condition, but at all sites during the ignore condition. A reliable amplitude decrement was not observed for the elderly in either the attend or ignore oddball series. The data suggest that attention differentially activates multiple generators that contribute to scalp-recorded novelty P3 activity. The lack of novelty P3 habituation seen in the elderly is consistent with changes in frontal lobe function as age increases.     

Gene dosage and down's syndrome: Metabolic and enzymatic changes in PC12 cells overexpressing transfected human liver-type phosphofructokinase

Down's syndrome (DS) is a human genetic disease caused by triplication of the distal third of chromosome 21 and overexpression of an unknown number of genes residing in it. The gene for the liver-type subunit of phosphofructokinase (PFKL), a key glycolytic enzyme, maps to this region and the product is overproduced in DS erythrocytes and fibroblasts. These facts, together with abnormalities which occur in DS glycolysis, make PFKL overexpression a candidate for causing some aspects of the DS phenotype. A cellular model for examining the consequences of PFKL overexpression in DS was constructed by transfecting rat PC12 cells with the human PFKL cDNA. Phosphofructokinase (PFK) isolated from PFKL-overexpressing clones was more inhibited by ATP and citrate and less activated by fructose-6-phosphate than control PFK; similar results were obtained when PFK preparations from DS and control fibroblasts were compared. In vivo NMR measurements determined that cells overexpressing PFKL performed glycolysis 40% faster than controls. These results show that overexpression of PFKL is the cause for altered biochemical regulatory characteristics of PFK in DS fibroblasts and can result in enhancement of glycolysis rates. It is also shown that increased gene dosage can exert its influence not merely by enhancing the amounts of gene products but also by altering their biochemical nature.     

Transcriptional profiling of target of RNAIII-activating protein, a master regulator of staphylococcal virulence

Staphylococcus aureus is a gram-positive bacterium that is part of the normal healthy flora but that can become virulent and cause infections by producing biofilms and toxins. The production of virulence factors is regulated by cell-cell communication (quorum sensing) through the histidine phosphorylation of target of RNAIII-activating protein (TRAP), which is a 21-kDa protein that is highly conserved among staphylococci. Using microarray analysis, we show here that the expression and phosphorylation of TRAP upregulate the expression of most, if not all, toxins known to date, as well as their global regulator agr. In addition, we show here that the expression and phosphorylation of TRAP are also necessary for the expression of genes known to be necessary for the survival of the bacteria in a biofilm, like arc, pyr, and ure. TRAP is thus demonstrated to be a master regulator of staphylococcal pathogenesis.     

Dissecting the mammalian synaptonemal complex using targeted mutations

In many organisms completion of the first meiotic cell division depends on the correct assembly and disassembly of the synaptonemal complex (SC). This is a structure discovered a little over 50 years ago, which is formed by the close association of axes of homologous sister chromatid pairs. Its structure varies between organisms, although it retains a common tripartite organization in species as evolutionarily distant as budding yeast and humans. In mammals it is essential for crossover formation and completion of meiosis. Components of the mammalian SC have been identified only in the last 15 years, and mouse genetic approaches have started revealing the importance for this structure only in the past 5 years. Here we discuss the progress that has been made in the field of the mammalian SC and what approaches could be considered for its further study.     

Assuring the quality of in-home supportive services: an evolving challenge

This article reports on the Ohio Quality Assurance Project, a two year demonstration. The project developed a model quality assurance system for in-home supportive services funded by Title III of the Older Americans Act including home health aide, personal care, homemaker, transportation and escort, home delivered meals, chore and home maintenance services. Using four planning and service areas in the state of Ohio comprising over 40 countries, the project developed, implemented and evaluated quality assurance standards and monitoring activities for Older Americans Act services. In addition, a second part of the project included in-depth case studies with consumers receiving in-home care.     

A better incision for pectus excavatum repair: avoiding the keloid triangle

The most common approach to the pepair of pectus excavatum and pectus carinatum deformities is via a central transverse submammary incision. The subsequent suprasternal scar is conspicuous and prone to hypertrophic and keloid scarring. To avoid the keloid triangle and to produce a less noticeable scar, we have utilized bilateral inframammary incisions for repairs of five female and two male patients with pectus defects. This approach provides excellent access for cartilage resection, sternotomy, and sternal tupport without increasing opearative time or compromising operative exposure. On follow-up for up to 25 months, all patients have had excellent cosmetic and functional results. Chest wall configuration and stability, wound healing, and scar formation have all been without complication. No keloid or hypertrophic scars have developed. To date, there has been no recurrence of pectus defects. We believe bilateral inframammary incisions are a superior approach for pectus repairs by enchancing cosmesis with less noticeable scars and fewer hypertropic and keloid scars, all without compromising operative exposure or increasing operative time.     

Alternative method for repair of the difficult infant hernia

BACKGROUND: Inguinal hernia repair in the small infant is often technically difficult. An alternative operative approach has been developed that can simplify troublesome repairs, while decreasing the potential risks of damage to cord structures and of recurrence. METHODS: Thirteen small infants (weight 1400-3000 grams) underwent inguinal hernia repair using a technique of direct closure of the internal inguinal ring via a trans-hernial sac approach. Dissection of cord structures from the sac was avoided. RESULTS: All hernia repairs remained intact on follow-up of 4-28 months. One patient early in the series developed a noncommunicating hydrocele, prompting the addition of sac eversion to the original technique. CONCLUSIONS: An alternative method for simplified repair of difficult infant hernias has been used with success. While it does not supplant traditional repair technique for most patients, it should be considered for use in selected situations.