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At least 919 records · Page 51Linked to original sources
PubMed1992

Mathematical assessment of the spatial distribution of Langerhans cells in guinea pig epidermis.

Two mathematical indexes, Hopkins-Skellam index (HSI) and Morisita index (MI), were applied to assess the distribution of ATPase-stained epidermal Langerhans cells (ELC) in the guinea pig skin. To our knowledge, this is the first report in which the degree of regularity has been expressed numerically by computation based on theoretical equations. The regularity of ELC in the normal skin was confirmed by the value of HSI (P < 0.0001). In the topical steroid applied skin, the number of ELC decreased significantly but the value of HSI was similar to that of the normal skin; while in the ultraviolet B (UVB) exposed skin, both number of ELC and regularity of ELC distribution decreased significantly. The graph of MI for the UVB exposed skin clearly showed that the distribution of ELC had local clumps. The two indexes, HSI and MI have been quite useful for determining the regularity of ELC. These indexes may have a wide application to other cells.

Animals↗
PubMed1992

A model for the determination of the 3D-spatial distribution of the functions of the hormone-binding domain of receptors that bind 3-keto-4-ene steroids.

A method of comparing the hydrophobic clusters of proteins (hydrophobic cluster analysis, HCA) has revealed that the 3D-folding pattern of the hormone-binding domain (HBD) of steroid hormone receptors (SHRs) may have an unexpectedly high degree of analogy with the known 3D-crystal structures of proteins belonging to the serine proteinase inhibitor (SERPIN) superfamily, e.g. alpha 1-antitrypsin and ovalbumin. The present paper briefly reviews some of the biochemical evidence that supports the structural validity of the SERPIN model and shows how the model can be used to establish hypothetical 3D-locations for functions attributed to different amino-acids or peptide sequences of the HBD: i.e. heat-shock protein binding, transcription activation, phosphorylation, steroid binding, but also ATP-binding. Indeed, the model has enabled the identification of a Rossmann-fold in SHRs that might bind ATP. Visualization of all these functions should help to interpret the chain of concerted events induced by steroid binding.

Amino Acid Sequence↗
PubMed2005

Imaging and spatial distribution of beta-amyloid peptide and metal ions in Alzheimer's plaques by laser ablation-inductively coupled plasma-mass spectrometry.

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) has been developed as a new strategy for detection and imaging of beta-amyloid protein in immunohistochemical sections from the brains of a transgenic mouse model of Alzheimer's disease. The distribution of beta-amyloid deposits in tissue was based on measurement of Eu- and Ni-coupled antibodies. The laser-based methodologies (spot ablation, single line raster, and two-dimensional imaging) were also used to detect and map trace element distributions and thus provide a novel probe for both elemental and protein data. We also report the combination of laser capture microdissection with LA-ICP-MS as an alternative strategy for microanalysis of immunohistochemical sections.

Alzheimer Disease↗
PubMed2006

Intravascular ultrasound assessment of the spatial distribution of ruptured coronary plaques in the left anterior descending coronary artery.

BACKGROUND: Plaque rupture is a substrate for thrombosis, occlusion, and myocardial infarction. The left anterior descending coronary artery (LAD) subtends the largest amount of myocardium; therefore, the location of LAD plaque rupture is of particular importance in detecting vulnerable plaques. The aim of our study was to assess the location of ruptured atherosclerotic plaques in the LAD. METHODS: Using intravascular ultrasound, we detected 160 ruptured LAD plaques. Of these, accurate intravascular ultrasound distance measurements (with consistent automatic transducer pullback [0.5 mm/s] to the LAD ostium) could be determined in 112 ruptured plaques. RESULTS: There were 104 patients (91 men, age 63.8 +/- 11.7 years). The total length of the LAD that was imaged measured 48.8 +/- 24.8 mm. The distance from the LAD origin to the maximal plaque cavity was 16.2 +/- 10.3 mm; the maximal plaque cavity was localized to the first 20 mm of the LAD in 71% and the first 30 mm in 88%. Only 2 ruptured plaques were found beyond 40 mm from the LAD ostium. CONCLUSIONS: The majority of LAD ruptured plaques are located within the proximal 30 mm of the artery. This area of the LAD should be targeted for vulnerable (rupture-prone) plaque detection and prevention.

Aged↗
PubMed2006

The Arf-family protein, Arl8b, is involved in the spatial distribution of lysosomes.

Lysosomes are late-endocytic organelles which primarily contribute to degradation and recycling of cellular material. From a previous proteomics study of purified rat liver lysosomal membranes we identified a protein from the Arf-family of small GTPases, Arl8b. Although proteins of the Arf-family have roles in a wide range of cellular functions, most notably roles in protein/vesicular trafficking, Arl8b represents the first from this protein family to be associated with a late-endocytic organelle. We demonstrate the co-localization of this protein with various lysosomal markers in different cell lines by confocal-immunofluorescence microscopy. We also show that GTP-restricted mutant Arl8b localizes to lysosomes and causes their redistribution to the periphery of the cell and into membrane projections. This indicates that Arl8b is involved in trafficking processes for lysosomes.

ADP-Ribosylation Factors↗
PubMed2006

Isolation of an eclosion hormone gene from the cotton bollworm, Helicoverpa armigera: temporal and spatial distribution of transcripts.

The cDNA encoding eclosion hormone (EH), which plays an integral role in triggering ecdysis behavior at the end of each molt, was cloned from the cotton bollworm, Helicoverpa armigera (Har) (Lepidoptera: Noctuidae). The EH polyprotein precursor contains a 26-amino acid signal peptide and a single 62-amino acid mature EH. Compared the mature Har-EH with other known EHs, it shows 94%, 84%, and 59% identities to Manduca sexta, Bombyx mori, and Drosophila melanogaster, respectively. Har-EH mRNA is expressed only in the brain by Northern blot and RT-PCR, but not in other tissues. By in situ hybridization and immunocytochemistry, both Har-EH mRNA and protein are localized in two pairs of neurosecretory cells of the brain. Prior to a molt, expression level of Har-EH gene reaches the highest point, and then drops after molt. EH release is detected both centrally, within the ganglia, and peripherally, into the hemolymph. A peak of the EH titer in hemolymph measured by ELISA presents at ecdysis. These results are consistent with the biological function of Har-EH associated with ecdysis. Furthermore, Har-EH gene is expressed throughout all of the developmental stages examined, implicating that the EH gene may possess other biological functions in post-embryonic development other than triggering ecdysis behavior.

Amino Acid Sequence↗
PubMed2005

Spatial distribution of polybrominated diphenyl ethers in coastal marine sediments receiving industrial and municipal effluents in Kuwait.

Polybrominated diphenyl ether (PBDE) concentrations were measured in surficial sediments from coastal sediments receiving industrial and municipal effluents in Kuwait. The summation PBDE concentrations varied by two orders of magnitude ranging from 80 to 3800 pg g(-1)dw. The congener distribution was dominated by BDE 183, with minor contributions from BDEs 154 and 153. The similarity between the congener profile to that of the technical octa formulation (Bromkal 79-8DE) suggests a source of this product in Kuwait. The observed gradient in concentration distribution, with high summation PBDE concentrations near the shore and an exponential decrease seaward, indicates that wastewater discharge from industrial activities in the study area is the primary source of these compounds in the sediments.

Environmental Monitoring↗
PubMed2004

Spatial distribution of the copepod Centropages typicus in Ligurian Sea (NW Mediterranean). Role of surface currents estimated by Topex-Poseidon altimetry.

A particle-tracking model was used to simulate the dispersion and development of the planktonic copepod Centropages typicus during spring in Ligurian Sea. We show that mesoscale current structure, with a coastal jet and eddies, plays a key role in the transport and dispersion of C. typicus during its life cycle. Although, in the north, offshore Nice, cohorts can be advected southwestward out of Ligurian basin, more to the south others are retained in the central eddy and may give the start to the spring bloom of this species. However, input of individuals from the south through the Corsican Channel and along the west coast of Corsica may also be important in spring. This study shows that the ambit of C. typicus population is larger than the Ligurian Sea.

Animals↗
PubMed2004

Spatial distribution of atmospheric PAHs and PCNs along a north-south Atlantic transect.

Ship-board air samples collected between The Netherlands and South Africa in January-February 2001 were analysed for polycyclic aromatic hydrocarbons (PAHs) and polychlorinated naphthalenes (PCNs). The highest PAH concentrations occurred in the European samples, and in samples close to West Africa and South Africa. Consistently low PAH concentrations were measured in the southern hemisphere open ocean samples (190-680 pg/m3). The highest PCN concentrations occurred in the European samples, but high values were also detected off the West African coast, and in the sample taken closest to South Africa. Data are presented for diurnal cycles taken in the remote South Atlantic. The day:night ratios of phenanthrene, 1-methylphenanthrene and fluoranthene were typically approximately 1.5-2.5:1. The mechanism(s) causing this observation is/are not understood at present, but dynamic environmental process(es) is/are implicated.

Air Pollutants↗
PubMed2006

Evidence for declining levels of heavy-metals in the Severn Estuary and Bristol Channel, U.K. and their spatial distribution in sediments.

Levels of heavy-metals (Cd, Cu, Cr, Ni, Pb and Zn) in suspended particulate and in surface and subsurface sediments were determined at seven locations in the Severn Estuary and Bristol Channel. Sediment metal concentrations were highest at sites close to industrial centres but levels have decreased significantly over the last 30 years so that they are now close to, or meet, environmental quality guidelines. The greatest metal concentrations in deposited sediments were usually associated with the finest particulates at locations with muddy sediments, but this was not always true at sites with predominantly sandy sediments. The metals bound to suspended particulates at all sites were remarkably consistent, presumably reflecting the mixing capacity of this macro-tidal estuary. The re-exposure of older, more contaminated sediments could explain the observed differences between deposited and suspended material. Sediment redistribution due to strong seasonal currents might also explain the differences between winter and summer samples.

Copper↗
PubMed2004

Temporal and spatial distributions of aerial contaminants in an enclosed pig building in winter.

Optimal management of indoor air quality in an enclosed swine house, especially in winter, is indispensable for preventing the transmission of infectious respiratory disease to workers and animals. Studies are needed to elucidate the correlation of aerial contaminants and climate factors. It was observed that indoor air contamination in an enclosed pig building was the highest at 2:00--5:00 PM, followed by 8:00--11:00 PM and 8:00--11:00 AM. It was assumed that this was attributed to the increase of swine activities in the afternoon. In general, the concentration of total dust and total airborne bacteria in an enclosed pig building was found to have a significant correlation with temperature and relative humidity (P<0.05). There were significant correlations between total dust and total airborne bacteria, between total dust and ammonia, and between total dust and odor at the 95% confidence level. In conclusion, temperature and total dust concentration correlated significantly with all parameters except hydrogen sulfide (H(2)S). This could have been due to the drying of swine feces due to the increase in interior temperature and the resuspension of feed deposited on the floor of the pig building by the swines' activity, resulting in a high generation of dust that adsorbed and carried the airborne bacteria and odorous compounds in the enclosed pig building. It was proved that an adsorptive capacity of dust for ammonia was higher than for hydrogen sulfide.

Air Microbiology↗
PubMed2005

A survey of spatially distributed exterior dust lead loadings in New York City.

This work documents ambient lead dust deposition values (lead loading) for the boroughs of New York City in 2003-2004. Currently, no regulatory standards exist for exterior concentrations of lead in settled dust. This is in contrast to the clearance and risk assessment standards that exist for interior residential dust. The reported potential for neurobehavioral toxicity and adverse cognitive development in children due to lead exposure prompts public health concerns about undocumented lead sources. Such sources may include settled dust of outdoor origin. Dust sampling throughout the five boroughs of NYC was done from the top horizontal portion of pedestrian traffic control signals (PTCS) at selected street intersections along main thoroughfares. The data (n=214 samples) show that lead in dust varies within each borough with Brooklyn having the highest median concentration (730 microg/ft2), followed in descending order by Staten Island (452 microg/ft2), the Bronx (382 microg/ft2), Queens (198 microg/ft2) and finally, Manhattan (175 microg/ft2). When compared to the HUD/EPA indoor lead in dust standard of 40 microg/ft2, our data show that this value is exceeded in 86% of the samples taken. An effort was made to determine the source of the lead in the dust atop of the PTCS. The lead in the dust and the yellow signage paint (which contains lead) were compared using isotopic ratio analysis. Results showed that the lead-based paint chip samples from intact signage did not isotopically match the dust wipe samples taken from the same surface. We know that exterior dust containing lead contributes to interior dust lead loading. Therefore, settled leaded dust in the outdoor environment poses a risk for lead exposure to children living in urban areas, namely, areas with elevated childhood blood lead levels and background lead dust levels from a variety of unidentified sources.

Air Pollutants↗
PubMed2005

Spatial distribution of bacterial phylotypes in the gut of the termite Reticulitermes speratus and the bacterial community colonizing the gut epithelium.

The bacterial community colonizing the gut wall of the termite Reticulitermes speratus was characterized without cultivation. Analysis of 16S rRNA genes after fractionation of the gut revealed that the bacterial composition on the gut wall was diverse and significantly different from that able to move unconfined in the gut fluid or physically associated with the gut protists. Actinobacteria, Firmicutes and Bacteroidetes were dominant on the gut wall, but Spirochaetes and the Termite group 1 phylum, abundant in the gut lumen, were relatively rare. A sequence-specific probe enabled the in situ detection of a rod-shaped Actinobacteria member, abundantly colonizing the gut paunch epithelium.

Animals↗
PubMed2006

Kinetics and spatial distribution of OTA in Aspergillus carbonarius cultures.

The aim of this study was to characterize Ochratoxin A (OTA) production by Aspergillus carbonarius under different environmental conditions, and to elucidate the diffusion capacity of OTA throughout synthetic medium. One strain belonging to the species A. carbonarius isolated from vine dried fruit was single-point inoculated onto triplicate synthetic nutrient medium plates at two water activities (0.92 and 0.97) and two temperatures (20 and 30 degrees C). Daily radii were measured and OTA production was tested after 4, 7, 10, 14 and 18 days of incubation at four distances from the centre of colony (1-4 cm). OTA production was detected mainly at 0.97 a(w). Earlier production was detected at 30 degrees C (optimum for growth), whereas maximum OTA concentrations were found at 20 degrees C. OTA production was detected from mycelium that was only a few days old and attained its optimum when mycelium was 4-7 days old at 0.97 a(w). OTA diffusion was observed at 0.92 a(w) and 20 degrees C. Thus OTA production is discernable in young A. carbonarius mycelium and diffusion of the toxin has been shown to occur in a solid substrate.

Aspergillus↗
PubMed2005

Spatial distribution of electrically induced high frequency vibration on basilar membrane.

We reported that the electrically evoked basilar membrane (BM) vibration at frequencies above the best frequency (BF) showed a lowest BM velocity magnitude, called a "dip", in the velocity-frequency spectra, indicating a cancellation. In the present study, we measured the high frequency BM motion as functions of the longitudinal and radial locations. Measurements were taken at three longitudinal locations in the first turn and the hook region: 14.9, 15.8 and 16.8 mm from the apex, corresponding to the BFs of 17, 21.3 and 28.0 kHz calculated from Greenwood [J. Acoust. Soc. Am. 87, 2592], and at different radial locations across the width of the BM. It was found that the dip frequency (DF) varied with the longitudinal and radial locations. In the longitudinal direction, the average value of the DF was 49.6, 55.6 and 72.8 kHz, respectively. Thus, the longitudinal distribution of the high frequency BM vibration was correlated with the BF. In the radial direction, there was consistent variation of the response spectrum such that the dip was mainly evident in the pectinate zone of the BM. These results imply that the high frequency BM motion is related to mechanical properties of the cochlear partition, including the outer hair cells (OHCs) themselves. Data also indicate different vibration modes across the width of the organ of Corti.

Acoustic Stimulation↗
PubMed2004

Spatial distribution of 3H, 90Sr, 137Cs and (239,240)Pu in surface waters of the Pacific and Indian Oceans--GLOMARD database.

The data stored in the IAEA's Global Marine Radioactivity Database (GLOMARD) developed in the framework of the IAEA's project "Worldwide Marine Radioactivity Studies (WOMARS)" have been evaluated for Pacific and Indian Ocean surface waters. Four anthropogenic radionuclides-- 3H, 90Sr, 137Cs and (239,240)Pu --have been chosen as the most representative of anthropogenic radioactivity in the marine environment, comprising beta, gamma and alpha-emitters which are the most frequently analysed in the marine environment and which have (with the exception of tritium) the highest potential contribution to radiation doses to humans via seafood consumption. For the purposes of this study, the Pacific and Indian Oceans were divided into latitudinal boxes for which average radionuclide concentrations were estimated for the year 2000. The highest concentrations have been observed in the Japan Sea/East Sea and the North-West Pacific Ocean, the lowest in the Southern Ocean.

Databases, Factual↗
PubMed2005

Characteristics, spatial distribution and vertical profile of gamma-ray emitting radionuclides in the coastal environment of North Sinai.

Radionuclide concentrations of beach and dune sand from various sites in Al-Arish city and surrounding area, North Sinai, Egypt, were measured. The sampling sites included locations in the local harbor, Al-Arish valley and Zaranik protected area. The results indicate that the activities of the products of (232)Th and (226)Ra series in samples from the harbor and along the beach were higher than those from non-coastal sites. The activity concentrations of (232)Th for beach sand ranged from 2.3 to 506.5 Bq/kg with an average of 83.4 Bq/kg, while that for dune sand ranged from 2.2 to 15.1 Bq/kg with an average of 6.4 Bq/kg. The average activity concentration of (226)Ra for beach sand was 56.0 Bq/kg (2.9-261.5 Bq/kg), while that for dune sand was 6.5 Bq/kg (3.0-14.7 Bq/kg). The average activity concentrations of (40)K for beach and dune sand were 88.1 Bq/kg and 178.4 Bq/kg, respectively. Six depth profiles in the harbor area were measured up to a depth of 1m within more than two years. These sets of measurements allowed the determination of the migration rate of black sand to be 0.094 cm/day. Samples with the smallest grain size (<0.2 mm) were found to have the highest level of activities, which were attributed to their high content of black sand. No risk exists for public health based on the calculated effective dose equivalent and the recommended limit of 5 mSv/y. On the other hand, local children and adults may receive doses higher than this recommended limit in two locations in the Zaranik protected area according to a model developed in this study.

Egypt↗