Plant nitrogen concentration and isotopic composition in residential lawns across seven US cities.

Human drivers are often proposed to be stronger than biophysical drivers in influencing ecosystem structure and function in highly urbanized areas. In residential land cover, private yards are influenced by individual homeowner preferences and actions while also experiencing large-scale human and biophysical drivers. We studied plant nitrogen (%N) and N stable isotopic composition (δ(15)N) in residential yards and paired native ecosystems in seven cities across the US that span major ecological biomes and climatic regions: Baltimore, Boston, Los Angeles, Miami, Minneapolis-St. Paul, Phoenix, and Salt Lake City. We found that residential lawns in three cities had enriched plant δ(15)N (P < 0.03) and in six cities higher plant N (%) relative to the associated native ecosystems (P < 0.05). Plant δ(15)N was progressively depleted across a gradient of urban density classes in Baltimore and Boston (P < 0.05). Lawn fertilization was associated with depleted plant δ(15)N in Boston and Los Angeles (P < 0.05), and organic fertilizer additions were associated with enriched plant δ(15)N in Los Angeles and Salt Lake City (P < 0.04). Plant δ(15)N was significantly enriched as a function of housing age in Baltimore (r (2) = 0.27, P < 0.02), Boston (r (2) = 0.27, P < 0.01), and Los Angeles (r (2) = 0.34, P < 0.01). These patterns in plant δ(15)N and plant N (%) across these cities suggests that N sources to lawns, as well as greater rates of N cycling combined with subsequent N losses, may be important drivers of plant N dynamics in lawn ecosystems at the national scale.

Dermoscopic features of common nevi: a review.

The differentiation between benign and worrisome melanocytic lesions may be challenging in the absence of the glaringly obvious clinical features that define a cutaneous malignancy. In such situations, dermoscopy may prove useful in further defining characteristics that are more indicative of a benign lesion, which can ultimately help avoid an unnecessary biopsy. Recognizing of the dermoscopic findings of benign nevi, taking into consideration the predominant pigment pattern and its organization, may aid in the evaluation of pigmented lesions. Benign nevi tend to exhibit symmetry, regularity in shape, and uniformity of dermoscopic structures. This article reviews the clinical and dermoscopic features of common acquired nevi (dermal, compound, and junctional), blue nevi, and congenital nevi.

Carbon, nitrogen, and phosphorus fluxes in household ecosystems in the Minneapolis-Saint Paul, Minnesota, urban region.

Rapid worldwide urbanization calls for a better understanding of the biogeochemical cycling of those macroelements that have large environmental impacts in cities. This study, part of the Twin Cities Household Ecosystem Project, quantified fluxes of carbon (C), nitrogen (N), and phosphorus (P) at the scale of individual households in the Minneapolis-Saint Paul metropolitan area in Minnesota, USA. We estimated input and output fluxes associated with several components of household activities including air and motor vehicle travel, food consumption, home energy use, landscape, pets, and paper and plastic use for 360 owner-occupied, stand-alone households. A few component fluxes dominated total input fluxes of elements. For instance, air and motor vehicle transportation, together with home energy use, accounted for 85% of total C consumption and emissions. All total and component fluxes were skewed to varying degrees, suggesting that policies targeting disproportionately high fluxes could be an effective and efficient way to reduce pollution. For example, 20% of households contributed 75% of air travel emissions and 40% of motor vehicle emissions. Home energy use was more nearly normally distributed. Nitrogen fluxes were dominated by human diet and lawn fertilizer applications, which together accounted for 65% of total household N inputs. The majority of P inputs were associated with human diet, use of detergents, and pet food. A large portion of the variation among household fluxes of C, N, and P was related to a few biophysical variables. A better understanding of the biophysical, demographic, and behavioral drivers of household activities that contribute to C, N, and P fluxes is pivotal for developing accurate urban biogeochemical models and for informing policies aimed at reducing sources of pollution in urban ecosystems.

Clinical and dermoscopic features of 88 scalp naevi in 39 children.

BACKGROUND: Paediatric scalp naevi may represent a source of anxiety for practitioners and parents, as the clinical and dermoscopic features of typical naevi have yet to be defined. Prompted by concern about the large size, irregular borders and colour variation of scalp naevi, clinicians and parents may request unnecessary excision of these naevi. OBJECTIVES: To establish the typical clinical and dermoscopic patterns of scalp naevi in children younger than 18 years old to help optimize clinical care and management. METHODS: Scalp naevi were imaged with a camera (Canon Rebel, XSi; Canon, Tokyo, Japan) and dermoscopic attachment (Dermlite Foto, 30 mm lens; 3Gen, San Juan Capistrano, CA, U.S.A.) to the camera. The clinical and dermoscopic images were reviewed and analysed. Both acquired and congenital scalp naevi were included but were not further differentiated from each other. RESULTS: We obtained clinical and dermoscopic images of 88 scalp naevi in 39 white children. Two subjects had received chronic immunosuppressive medication. Nineteen children had a family history of melanoma. Boys (18/39 subjects, 46%) possessed 68% (60 naevi) of scalp naevi imaged. Younger (< 10 years old) subjects (24/39 subjects, 62%) possessed 42% (37 naevi) of scalp naevi. The main clinical patterns included eclipse (n=18), cockade (n = 3), solid brown (n=42) and solid pink (n=25) naevi. Solid-coloured naevi showed the following dermoscopic patterns: globular (57%), complex (reticular-globular) (27%), reticular (9%), homogeneous (6%) and fibrillar (1%). The majority of naevi had a unifying feature - perifollicular hypopigmentation, which caused the appearance of scalloped, irregular borders if occurring on the periphery, or variegation in pigmentation, if occurring within the naevi. CONCLUSIONS: Older subjects and boys tend to harbour a larger proportion of scalp naevi. The main clinical patterns include solid-coloured and eclipse naevi. The most common dermoscopic pattern of scalp naevi is the globular pattern. Perifollicular hypopigmentation is a hallmark feature of signature scalp naevi. Dermoscopy is a noninvasive tool in the evaluation of cutaneous melanocytic lesions in children and may decrease the number of unnecessary excisions.

Oxidative damage and protection of the RPE.

This review provides a model for the role of oxidative stress in the etiology of age-related macular degeneration (AMD). Epidemiological studies of diet, environmental and behavioral risk factors suggest that oxidative stress is a contributing factor of AMD. Pathological studies indicate that damage to the retinal pigment epithelium (RPE) is an early event in AMD. In vitro studies show that oxidant treated RPE cells undergo apoptosis, a possible mechanism by which RPE cells are lost during early phase of AMD. The main target of oxidative injury seems to be mitochondria, an organelle known to accumulate genomic damages in other postmitotic tissues during aging. The thiol antioxidant GSH and its amino acid precursors protect RPE cells from oxidant-induced apoptosis. Similar protection occurs with dietary enzyme inducers which increase GSH synthesis. These results indicate that therapeutic or nutritional intervention to enhance the GSH antioxidant capacity of RPE may provide an effective way to prevent or treat AMD.

Effect of dietary inducer dimethylfumarate on glutathione in cultured human retinal pigment epithelial cells.

PURPOSE: To determine the effect of dimethylfumarate (DMF), an inducer of glutathione (GSH)-dependent detoxification, on intracellular GSH levels in cultured human retinal pigment epithelium (hRPE) cells, its mechanism of action, and its effect on hRPE cells subjected to oxidative injury. METHODS: Established hRPE cell lines were treated with DMF and assayed by high-pressure liquid chromatography for intracellular and extracellular GSH levels. Quantification of gamma-glutamylcysteine synthetase (GLCL) was determined through northern and western blot analyses, and activity was measured. Effects of pretreatment with DMF on GSH redox status of hRPE cells was determined. Sensitivity of hRPE cells to oxidative stress was determined using tert-butylhydroperoxide as the oxidative agent. RESULTS: Dimethylfumarate caused a transient decrease followed by a significant increase in intracellular GSH. Glutathione increased maximally at 24 hours with 100 to 200 microM DMF. The initial decrease could be accounted for by the formation of a DMF-GSH conjugate. Dimethylfumarate treatment increased the steady state mRNA expression of the regulatory subunit of GLCL, but no increase was seen for the catalytic subunit. However, protein levels were increased for both, and the catalytic activity of GLCL was also increased. Whereas the initial decrease in GSH made hRPE cells more susceptible to oxidative damage, pretreatment with DMF under conditions that increased intracellular GSH protected hRPE cells against oxidative damage. CONCLUSIONS: These results suggest a means by which the antioxidant capability of hRPE may be augmented without direct antioxidant supplementation. Specifically, a dietary compound that conjugates with GSH can induce GSH synthesis, increase GSH concentration, and improve protection by GSH-dependent detoxification pathways in hRPE. However, the early depletion of GSH before stimulated synthesis necessitates caution in prevention strategies using dietary inducers.

A protein phosphatase methylesterase (PME-1) is one of several novel proteins stably associating with two inactive mutants of protein phosphatase 2A.

Carboxymethylation of proteins is a highly conserved means of regulation in eukaryotic cells. The protein phosphatase 2A (PP2A) catalytic (C) subunit is reversibly methylated at its carboxyl terminus by specific methyltransferase and methylesterase enzymes which have been purified, but not cloned. Carboxymethylation affects PP2A activity and varies during the cell cycle. Here, we report that substitution of glutamine for either of two putative active site histidines in the PP2A C subunit results in inactivation of PP2A and formation of stable complexes between PP2A and several cellular proteins. One of these cellular proteins, herein named protein phosphatase methylesterase-1 (PME-1), was purified and microsequenced, and its cDNA was cloned. PME-1 is conserved from yeast to human and contains a motif found in lipases having a catalytic triad-activated serine as their active site nucleophile. Bacterially expressed PME-1 demethylated PP2A C subunit in vitro, and okadaic acid, a known inhibitor of the PP2A methylesterase, inhibited this reaction. To our knowledge, PME-1 represents the first mammalian protein methylesterase to be cloned. Several lines of evidence indicate that, although there appears to be a role for C subunit carboxyl-terminal amino acids in PME-1 binding, amino acids other than those at the extreme carboxyl terminus of the C subunit also play an important role in PME-1 binding to a catalytically inactive mutant.

Oxidant-induced apoptosis in cultured human retinal pigment epithelial cells.

PURPOSE: To determine the mechanism of oxidant-induced cell death in cultured human retinal pigment epithelium (hRPE). METHODS: Cultured hRPE cells were treated with different concentrations of a chemical oxidant, t-butylhydroperoxide (tBH), for different periods of time. Apoptosis was determined with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) and flow cytometry. Mitochondrial membrane potential (mtdelta psi) was measured by rhodamine 123 staining and subsequent flow cytometry. Release of mitochondrial cytochrome c (cyt c) and cleavage of procaspase 3 and caspase substrates were determined by western blot analysis. RESULTS: t-Butylhydroperoxide caused time- and dose-dependent activation of apoptosis in hRPE, indicated by characteristic morphologic changes; TUNEL-positive labeling; phosphatidylserine (PS) exposure; and procaspase 3, poly(ADP-ribose)polymerase, lamin, and tubulin cleavage. An early decrease of mtdelta psi was observed before caspase activation, together with the release of mitochondrial cyt c. CONCLUSIONS: Results indicate that tBH can induce apoptosis in hRPE, probably by triggering the mitochondrial permeability transition, which results in swelling and release of mitochondrial intermembrane proteins.

Familial multiple blue nevi.

The blue nevus most commonly presents as a solitary blue nodule. Four histologic variants of blue nevus have been described. Rarely, multiple blue nevi blue nevi may occur in a single person. Only 1 case of familial multiple blue nevi has been described.

The division of neuronal progenitor cells during migration in the neonatal mammalian forebrain.

In the mammalian forebrain most neurons originate from proliferating cells in the ventricular zone lining the lateral ventricles. These neurons become postmitotic before they undergo migration to their final destinations. In this study we examined the proliferative and migratory properties of cells destined for the olfactory bulb that arise postnatally from progenitor cells situated at the anterior extent of the subventricular zone (SVZa). The SVZa-derived cells migrate along a stereotypical pathway to the olfactory bulb where they become interneurons. Using lineage tracers and the cell proliferation marker BrdU, we have demonstrated that SVZa-derived cells in the rat retain the capacity for division after migrating away from their initial site of generation. These cells also express a neuron-specific tubulin, recognized by the antibody TuJ1. These results suggest that, unlike other immature neurons, these SVZa-derived cells have made a commitment to become neurons before becoming postmitotic.

The relationship between isometric contraction durations and improvement in shoulder joint range of motion.

Proprioceptive Neuromuscular Facilitation (PNF) flexibility techniques are now being used in health and sports related activities, yet it is unclear as to the relationship between various isometric contraction time increments and joint range of motion. The purpose of this study, therefore, was to determine the relationship between a three-second, six-second, and ten-second maximum voluntary isometric contraction (MVIC). A modified PNF procedure referred to as the slow-reversal-hold-relax (SRHR) flexibility technique was employed in the investigation. It was hypothesized that longer MVIC time increments used with the SRHR flexibility technique would provide greater range of motion (ROM). Specifically, the ten-second MVIC was believed to be superior to the six-second and three-second MVIC. Furthermore, it was hypothesized that the six-second MVIC was superior to the three-second MVIC. Sixty subjects, ages 14-57 were randomly assigned to one of three treatment groups. Using a Leighton Flexometer, acute internal rotation of the shoulder joint was measured in degrees for six trials. Three passive stretch trials served as the baseline measurement for each subject (trials 1-3). The SRHR flexibility technique was used as the treatment for trials 4-6. A sixty-second rest interval common to clinical settings was integrated between each trial. The hypothesis was not accepted that a positive correlation existed between increased MVIC time and greater ROM.