Lung preservation solution substrate composition affects rat lung oxidative metabolism during hypothermic storage

Lungs harvested for transplantation utilize oxygen after procurement. We investigated the effects of storage solution substrate composition on pulmonary oxidative metabolism and energetics during the preservation interval. Rat lungs were harvested and stored at 10 degrees C in low-potassium dextran (LPD) solution. Groups of lungs were preserved with preservation solution containing 5mM carbon-13 ((13)C) labeled glucose or increasing concentrations of (13)C labeled pyruvate. Additional groups of rat lungs were studied with dichloroacetate (DCA) added to the pyruvate-modified preservation solutions. Oxidative metabolism (measured by (13)C-enrichment of glutamate) and adenine nucleotide levels were quantified. Increasing preservation solution pyruvate concentration augmented glutamate (13)C-enrichment up to a concentration of 32mM pyruvate. DCA further stimulated oxidative metabolism only at lower concentrations of pyruvate (4 and 8mM). ATP and ADP were not different among groups, but AMP levels were higher in the glucose group. These data suggest that altering the substrate composition of the preservation solution influences lung metabolism during allograft preservation for transplantation.     

Functional characterization of GABA(A) receptors in neonatal hypothalamic brain slice

The hypothalamus influences a number of autonomic functions. The activity of hypothalamic neurons is modulated in part by release of the inhibitory neurotransmitter GABA onto these neurons. GABA(A) receptors are formed from a number of distinct subunits, designated alpha, beta, gamma, delta, epsilon, and theta, many of which have multiple isoforms. Little data exist, however, on the functional characteristics of the GABA(A) receptors present on hypothalamic neurons. To gain insight into which GABA(A) receptor subunits are functionally expressed in the hypothalamus, we used an array of pharmacologic assessments. Whole cell recordings were made from thin hypothalamic slices obtained from 1- to 14-day-old rats. GABA(A) receptor-mediated currents were detected in all neurons tested and had an average EC(50) of 20 +/- 1.6 microM. Hypothalamic GABA(A) receptors were modulated by diazepam (EC(50) = 0.060 microM), zolpidem (EC(50) = 0.19 microM), loreclezole (EC(50) = 4.4 microM), methyl-6,7-dimethoxy-4-ethyl-beta-carboline (EC(50) = 7.7 microM), and 5alpha-pregnan-3alpha-hydroxy-20-one (3alpha-OH-DHP). Conversely, these receptors were inhibited by Zn(2+) (IC(50) = 70.5 microM), dehydroepiandrosterone sulfate (IC(50) = 16.7 microM), and picrotoxin (IC(50) = 2.6 microM). The alpha4/6-selective antagonist furosemide (10-1,000 microM) was ineffective in all hypothalamic neurons tested. The results of our pharmacological analysis suggest that hypothalamic neurons express functional GABA(A) receptor subtypes that incorporate alpha1 and/or alpha2 subunits, beta2 and/or beta3 subunits, and the gamma2 subunit. Our results suggest receptors expressing alpha3-alpha6, beta1, gamma1, and delta, if present, represent a minor component of functional hypothalamic GABA(A) receptors.     

Discrepancies between self-reported years of education and estimated reading level among elderly community-dwelling African-Americans: Analysis of the MOAANS data.

The influence of education on cognition has received a great deal of attention in the literature. Although there is general consensus regarding the importance of education on cognitive functioning, the extent to which self-reported level of education corresponds to true educational attainment remains unclear, especially in ethnic minority populations where equal access to education has not always been available. Several investigators have suggested that reading skill may serve as a quantitative estimate of true education experience. Among African-Americans, however, research has shown that self-reported educational level consistently over predicts estimated reading level. The current study analyzed the discrepancy between self-reported years of education completed and estimated reading level in a sample of community-dwelling, elderly African-Americans participating in Mayo's Older African Americans Normative Studies (MOAANS) (Lucas, J.A., Ivnik, R.J., Willis, F.B., Ferman, T.J., Smith, G.E., Parfitt, F.C., Petersen, R.C., & Graff-Radford, N.R. (2005). Mayo's Older African Americans Normative Studies: Normative data for commonly used clinical neuropsychological measures. The Clinical Neuropsychologist, 19, 162-183). In this sample, 29% of the participants read at a level that was 3 or more years below what would be expected based on self-report of education attained. This study also sought to evaluate the extent to which this discrepancy fluctuated as a function of demographic variables such as location of schooling (urban, suburban, rural; North vs. South), parental education and literacy, and percentage of segregation in schooling. Implications of these results are discussed, as are areas for further inquiry.     

The midsagittal area of the corpus callosum and total neocortical volume differ in three inbred strains of mice

Differences in the midsagittal area of the corpus callosum have been reported between human males and females, between handled and nonhandled rats, and both within and between various strains of mice. This measure has, in addition, been related to handedness in humans and "pawedness" in certain strains of mice. The present study investigated the between- and within-strain differences in three inbred strains of mice, two with autoimmune disorders and spontaneously occurring developmental neuropathology, in the midsagittal area of the corpus callosum, the total neocortical volume, and the asymmetry of the neocortex. These morphometric measures were obtained from coronally sectioned celloidin-embedded material from New Zealand Black (NZB/BINJ), BXSB/MpJ, and DBA/2J mouse strains. NZB mice had a total neocortical volume larger than that of either the BXSB or DBA strains, whereas the BSXB mice had a midsagittal area of the corpus callosum larger than that of either of the other two strains. In addition, there was a positive correlation between these two measures. There was no correlation between total neocortical asymmetry and midsagittal area of the corpus callosum in any of the three strains. Finally, there were no differences in any morphometric measure between animals with or without developmental neuropathology in any given strain.     

Emerging concepts of structure-function dynamics in adult brain: The hypothalamo-neurohypophysial system

As the first known of the mammalian brain's neuropeptide systems, the magnocellular hypothalamo-neurohypophysial system has become a model. A great deal is known about the stimulus conditions that activate or inactivate the elements of this system, as well as about many of the actions of its peptidergic outputs upon peripheral tissues. The well-characterized actions of two of its products, oxytocin and vasopressin, on mammary, uterine, kidney and vascular tissues have facilitated the integration of newly discovered, often initially puzzling, information into the existing body of knowledge of this important regulatory system. At the same time, new conceptions of the ways in which neuropeptidergic neurons, or groups of neurons, participate in information flow have emerged from studies of the hypothalamo-neurohypophysial system. Early views of the SON and PVN nuclei, the neurons of which make up approximately one-half of this system, did not even associate these interesting, darkly staining anterior hypothalamic cells with hormone secretion from the posterior pituitary. Secretion from this part of the pituitary, it was thought, was neurally evoked from the pituicytes that made the oxytocic and antidiuretic "principles" and then released them upon command. When these views were dispelled by the demonstration that the hormones released from the posterior pituitary were synthesized in the interesting cells of the hypothalamus, the era of mammalian central neural peptidergic systems was born. Progress in developing an ever more complete structural and functional picture of this system has been closely tied to advancements in technology, specifically in the areas of radioimmunoassay, immunocytochemistry, anatomical tracing methods at the light and electron microscopic levels, and sophisticated preparations for electrophysiological investigation. Through the judicious use of these techniques, much has been learned that has led to revision of the earlier held views of this system. In a larger context, much has been learned that is likely to be of general application in understanding the fundamental processes and principles by which the mammalian nervous system works.(ABSTRACT TRUNCATED AT 400 WORDS)