An integrated WRF/HYSPLIT modeling approach for the assessment of PM(2.5) source regions over the Mississippi Gulf Coast region.

Fine particulate matter (PM(2.5)) is majorly formed by precursor gases, such as sulfur dioxide (SO(2)) and nitrogen oxides (NO(x)), which are emitted largely from intense industrial operations and transportation activities. PM(2.

Age-related retention of fiber cell nuclei and nuclear fragments in the lens cortices of multiple species.

Purpose: To determine the differences between species in the retention of lens fiber cell nuclei and nuclear fragments in the aging lens cortex and the relationship of nuclear retention to lens opacity. For this purpose old human, monkey, dog, and rat lenses were compared to those of three strains of mouse. We also investigated possible mechanisms leading to nuclear retention.

X-ray induced cataract is preceded by LEC loss, and coincident with accumulation of cortical DNA, and ROS; similarities with age-related cataracts.

Purpose: To compare age-related cataractous (ARC) changes in unirradiated mice lenses to those induced by head-only X-irradiation of 3 month-old mice.

Methods: lens epithelial cells (LECs) as well as partially degraded cortical DNA were visualized in fixed sections using 4',6-diamidino-2-phenylindole (DAPI) staining, and in fresh lenses using the vital stain Hoechst 33342. reactive oxygen species (ROS) activity was also visualized directly in fresh lenses using the vital dye Dihydrorhodamine (DHR).

Radiation cataracts: mechanisms involved in their long delayed occurrence but then rapid progression.

Purpose: This study was directed to assess the DNA damage and DNA repair response to X-ray inflicted lens oxidative damage and to investigate the subsequent changes in lens epithelial cell (LEC) behavior in vivo that led to long delayed but then rapidly developing cataracts.

Methods: Two-month-old C57Bl/6 female mice received 11 Grays (Gy) of soft x-irradiation to the head only. The animals' eyes were examined for cataract status in 30 day intervals by slit lamp over an 11 month period post-irradiation.

Dietary restriction suppresses proteotoxicity and enhances longevity by an hsf-1-dependent mechanism in Caenorhabditis elegans.

Dietary restriction increases lifespan and slows the onset of age-associated disease in organisms from yeast to mammals. In humans, several age-related diseases are associated with aberrant protein folding or aggregation, including neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases. We report here that dietary restriction dramatically suppresses age-associated paralysis in three nematode models of proteotoxicity.

Cellular debris and ROS in age-related cortical cataract are caused by inappropriate involution of the surface epithelial cells into the lens cortex.

Purpose: To quantify changes in the lens epithelial cells and underlying lens cortex responsible for age-related cortical cataract (ARCC) in the rat.

Methods: Freshly isolated lenses were stained vitally for DNA with Hoechst 33342. Reactive oxygen species (ROS) and mitochondria were visualized and quantified by dihydrorhodamine 123 (DHR).

Accumulation of DNA, nuclear and mitochondrial debris, and ROS at sites of age-related cortical cataract in mice.

Purpose: Lenses from young and old mice were analyzed by laser scanning confocal microscopy (LSCM) with vital dyes, to determine whether age-related subcapsular and cortical cataracts were linked to the failure of lens fiber cells to degrade nuclei, DNA, and mitochondria properly and whether they result in the overproduction of reactive oxygen species (ROS) at the same sites.

Results: As opposed to the clear DNA-free subcapsular and cortical areas of young adult mouse lenses, these areas in cataractous old mouse lenses were found to contain accumulations of nuclei, nuclear fragments, aggregated mitochondria, and amorphous DNA as cortical inclusions (P < 0.001 between young and old lenses).

Age-related cataract progression in five mouse models for anti-oxidant protection or hormonal influence.

Five mouse models with known alterations of resistance to oxidative damage were compared by slit lamp examination for the presence and degree of advancement of age-related cataract in young adult and old animals along with wild type controls. A group of young and old normal C57BL/6Jax mice were examined first to constitute a standard, and they were found to exhibit age-related cataract development. Following this, four models on the C57BL/6 background with imposed genetic alterations affecting anti-oxidant enzyme presence or activity, and one outbred model in which a deletion blocked the growth hormone/IGF-1 axis, were similarly examined.

Efficacy of MitoTracker Green and CMXrosamine to measure changes in mitochondrial membrane potentials in living cells and tissues.

Background: Chloromethyl-X-rosamine (CMXRos) and MitoTracker Green (MTG) have proved to be useful dyes with which to measure mitochondrial function. CMXRos is a lipophilic cationic fluorescent dye that is concentrated inside mitochondria by their negative mitochondrial membrane potential (MMP). MTG fluorescence has been used as a measure of mitochondrial mass independent of MMP.

White light-mediated DNA strand breaks in lens epithelial cells.

It was hypothesized that white light can induce DNA single-strand breaks/alkali labile sites in lens epithelial cells during the dissection process when lenses are being collected for study. Dissection of lenses in white light significantly increased 'Integrated Intensity' (P=0.0216), an index of DNA single strand breaks/alkali labile sites, using the alkaline microgel electrophoresis assay.

Age-related telomere shortening occurs in lens epithelium from old rats and is slowed by caloric restriction.

We have investigated whether the average relative telomere length of lens epithelial cells (LECs) from brown Norway rats decreases with the age of the donor animal, and whether chronic caloric restriction (CR) of the rats delays the telomere shortening. Our previous studies have demonstrated that clonal proliferative potential of rodent LECs as well as the in vivo rate of DNA synthesis decreases with age and that this decrease is slowed by chronic lifelong caloric restriction (CR). In order to determine if telomeric shortening might be involved in this loss of proliferative potential, we examined relative telomeric lengths in young, old ad lib fed (AL), and old calorically restricted (CR) brown Norway rats.

Normal mouse and rat strains as models for age-related cataract and the effect of caloric restriction on its development.

The purpose of this study was to determine: (1) which of the commonly used strains of laboratory rats and mice provide good models for human age-related cataract, and (2) whether long term caloric restriction, a regimen that prolongs both median and maximum life span in rodents, would also delay the time of appearance of this age-related pathology. Three strains of mice and two rat strains commonly used in laboratory work and maintained on either ad libitum (AL) or calorically restricted (CR) diets in the National Institutes of Aging and Diet Restriction colony were examined by slit lamp for age-related cataracts at four or more time points during their life spans. These strains were Brown Norway and Fischer 344 rats, and C57BL/6, (C57BL6 x DBA/2)F1 and (C57BL/6 x C3H)F1 mice.

The relationships of animal age and caloric intake to cellular replication in vivo and in vitro: a review.

This brief review examines aging at the cellular level as expressed by cell replication rates in vivo, clone size limits in vitro, and cell function in several tissues and organs. Studies are presented in which in vivo and in vitro cell replication measurements were made for several cell types and organs in relation to animal age, diet, life span, and specific age-related pathologies. Among the events examined that affect cell replication and cell survival in vitro and in vivo over a lifetime are oxidative damage, telomere shortening, and hormone and hormone receptor level changes.

Cellular proliferation potential during aging and caloric restriction in rhesus monkeys (Macaca mulatta).

Caloric restriction (CR) is the most successful method of extending both median and maximal lifespans in rodents and other short-lived species. It is not yet clear whether this method of life extension will be successful in longer-lived species, possibly including humans; however, trials in rhesus monkeys are underway. We have examined the cellular proliferative potential of cells from CR and AL (ad libitum fed) monkey skin cells using two different bioassays: colony size analysis (CSA) of dermal fibroblasts isolated and cloned directly from the skin and beta-galactosidase staining at pH 6.

Analysis of the capacity of extracts from normal human young and senescent fibroblasts to support DNA synthesis in vitro.

Cytoplasmic extracts from early-passage (young), late-passage (senescent) normal human fibroblast (HF) cultures and immortalized human cell lines (HeLa, HT-1080, and MANCA) were analyzed for their ability to support semiconservative DNA synthesis in an in vitro SV40-ori DNA replication system. Unsupplemented extracts from the three permanent cell lines were demonstrated to be active in this system; whereas young HF extracts were observed to be minimally active, and no activity could be detected in the senescent HF extracts. The activity of these extracts was compared after supplementation with three recombinant human replication factors: (1) the catalytic subunit of DNA polymerase alpha (DNA pol-alpha-cat), (2) the three subunits of replication protein A (RPA), and (3) DNA topoisomerase I (Topo I).

Response of lens epithelial cells to hydrogen peroxide stress and the protective effect of caloric restriction.

Hydrogen peroxide (H2O2) has been reported to be present at significant levels in the lens and aqueous humor in some cataract patients and suggested as a possible source of chronically inflicted damage to lens epithelial (LE) cells. We measured H2O2 effects on bovine and mouse LE cells and determined whether LE cells from old calorically restricted mice were more resistant to H2O2-induced cellular damage than those of same age ad libitum fed (AL) mice. Bovine lens epithelial cells were exposed to H2O2 at 40 or 400 microM for 2 h and then allowed to recover from the stress.

Neovascularization in aged mice: delayed angiogenesis is coincident with decreased levels of transforming growth factor beta1 and type I collagen.

Angiogenesis, the growth of new vessels from existing microvasculature, is delayed in aged animals. In this study we asked whether this impairment might be due, in part, to changes in the expression of a growth factor, transforming growth factor-beta1 (TGF-beta1), and a matrix protein, type I collagen, which have been shown to regulate angiogenesis in vivo. We implanted polyvinyl alcohol sponges subcutaneously in the dorsa of young and aged mice and examined the sponges 7 to 21 days later for the presence of invasive fibrovascular bundles.

Cellular proliferative capacity and life span in small and large dogs.

In a study comparing animal life spans and in vitro clonal proliferative capacity of skin fibroblasts in groupings of small, middle, large, and very large breeds of dogs of specific ages, the following results were obtained: (1) their life spans were inversely correlated to the frame sizes of the breeds; (2) the percent of large clones present in clone size distributions from the small dogs was inversely proportional to the age of the subjects (this was not true for the large breeds; however, animals older than 8 years were not available in those breeds); and (3) the group composed of the two largest breeds (Great Dane and Irish Wolfhound) had the shortest life spans and also had significantly smaller percentages of large skin fibroblast clones formed in vitro than either of the two groupings of smaller dogs at any age studied. It appears that within the domestic dogs the large body size is accompanied by shorter life span and, in the two largest breeds, decreased cellular growth potential.

Enhanced cell proliferation and biosynthesis mediate improved wound repair in refed, caloric-restricted mice.

Aged mice that have undergone long-term caloric-restriction (CR) have improved health and enhanced longevity in comparison to aged mice that are ad libitum-fed (AL). However, caloric-restriction does not benefit the impaired wound healing of aged mice. To test the hypothesis that CR mice have the capacity for enhanced wound repair, but require a short-term period of additional nutrient intake to show this advantage, we assessed wound healing in CR mice that had been refed (RF) an ad libitum diet for 4 weeks prior to wounding.

Caloric restriction: conservation of in vivo cellular replicative capacity accompanies life-span extension in mice.

In male mice of a long-lived hybrid strain (B6D2F1), long-term 40% caloric restriction (CR) extended both mean and maximum life spans by 36 and 20%, respectively, over that of ad libitum fed (AL) controls. Measurements of entry into S-phase were made in vivo of six different cell types in five different organs using 2-week exposures to BrdU. The labeling index (L.

Caloric restriction: conservation of cellular replicative capacity in vitro accompanies life-span extension in mice.

We have tested whether life-long caloric restriction (CR) slows or delays the age-related loss of cellular replicative potential that occurs during normal aging in ad libitum (AL) fed mice. Both mean and maximum life spans of the restricted animals (60% of AL intake) were significantly extended 30-40% by CR treatment. Proliferative potential, measured by determining the fraction of cells capable of forming large clones in vitro, was compared in five cell types from six tissue sites from two strains of mice (Male (C57BL/6 x DBA/2)F1("B6D2F1") and female (C57BL/6 x C3H)F1("B6C3F1")).

Murine temperature-sensitive DNA polymerase alpha mutant displays a diminished capacity to stimulate DNA synthesis in senescent human fibroblast nuclei in heterokaryons at the nonpermissive condition.

We have investigated the capacity of a murine cell line with a temperature-sensitive (ts) mutation in the DNA polymerase alpha (Pola) locus and a series of ts non-Pola mutant cell lines from separate complementation groups to stimulate DNA synthesis, in senescent fibroblast nuclei in heterokaryons. In the Pola mutant x senescent heterodikaryons, both human and murine nuclei display significantly diminished levels of DNA synthesis at the restrictive temperature (39.5 degrees C) as determined by [3H]thymidine labeling in autoradiographs.

Decrease in cellular replicative potential in "giant" mice transfected with the bovine growth hormone gene correlates to shortened life span.

Adult mice, (C57BL/6 x Sjl)F1 hybrids, transfected with the bovine growth hormone gene (bGH) grow to twice normal size, but have a mean life span less than 50% that of control siblings without the transgene. The replicative potentials of cells from six different tissue sites (tail skin and ear skin dermal fibroblasts, tail subdermal connective tissue fibroblasts, kidney medulla epithelial cells, bone marrow myofibroblasts, and spleen myofibroblasts) were assayed in vitro using clone size distribution analysis. Cells from all of the above bGH+ tissues produced a smaller fraction of large clones, relative to age-matched controls, in all of these cell types.

An age-related reduction in the replicative capacity of two murine hematopoietic stroma cell types.

Two stromal cell types, myofibroblasts and endothelial-like cells, that were identifiable by structural and antigenic specificities, were obtained from murine bone marrow and spleen of young, middle-aged, and old mice of two strains and sexes and grown in liquid culture for 9 or 10 days. As expected, there were more total nucleated cells per organ in the old mice (with larger organs) than in the young mice. However, the concentration of stromal colony forming cells was greater in the young mice, resulting in the number of colony forming cells per organ not being significantly different in most comparisons.