scholarly journals Signal-mediated nuclear transport in proliferating and growth-arrested BALB/c 3T3 cells.

1991 ◽  
Vol 115 (4) ◽  
pp. 933-939 ◽  
Author(s):  
C M Feldherr ◽  
D Akin
Keyword(s):  
High Cell Density ◽  
Unit Length ◽  
3T3 Cells ◽  
Proliferating Cells ◽  
Gold Particles ◽  
Nuclear Uptake ◽  
Large Particles ◽  
The Mean ◽  
Transport Channels ◽  
Relative Uptake

Mediated transport across the nuclear envelope was investigated in proliferating and growth-arrested (confluent or serum starved) BALB/c 3T3 cells by analyzing the nuclear uptake of nucleoplasmin-coated colloidal gold after injection into the cytoplasm. Compared with proliferating cells the nuclear uptake of large gold particles (110-270 A in diameter, including the protein coat) decreased 5.5-, 33-, and 78-fold, respectively, in 10-, 14-17-, and 21-d-old confluent cultures; however, the relative uptake of small particles (total diameter 50-80 A) did not decrease with increasing age of the cells. This finding suggests that essentially all pores remain functional in confluent populations, but that most pores lose their capacity to transport large particles. By injecting intermediate-sized gold particles, the functional diameters of the transport channels in the downgraded pores were estimated to be approximately to 130 and 110 A, in 14-17- and 21-d-old cultures, respectively. In proliferating cells, the transport channels have a functional diameter of approximately 230 A. The mean diameters of the pores (membrane-to-membrane distance) in proliferating and confluent cells (728 and 712 A, respectively) were significantly different at the 10%, but not the 5%, level. No differences in pore density (pore per unit length of membrane) were detected. Serum-deprived cells (7-8 d in 1% serum or 4 d in 0.5% serum) also showed a significant decrease in the nuclear uptake of large, but not small, gold particles. Thus, the permeability effects are not simply a function of high cell density but appear to be growth related. The possible functional significance of these findings is discussed.

Variations in signal-mediated transport through the nuclear pores as a function of cellular activity

1992 ◽  
Vol 50 (1) ◽  
pp. 494-495
Author(s):  
C.M. Feldherr ◽  
D. Akin
Keyword(s):  
Nuclear Localization ◽  
Pore Diameter ◽  
Cellular Activity ◽  
3T3 Cells ◽  
Nuclear Pores ◽  
Gold Particles ◽  
Nuclear Localization Signals ◽  
Nuclear Uptake ◽  
Quiescent Cells ◽  
Transport Channels

Previously, we utilized colloidal gold particles coated with nucleoplasmin, which contains well characterized nuclear localization signals (NLS), to study signal-mediated nuclear transport in proliferating and quiescent BALB/c 3T3 cells. The particles were injected into the cytoplasm, and nuclear uptake (N/C gold ratios) was later determined by TEM. The functional size of the transport channels was also analyzed by measuring the particles that entered the nucleoplasm. When large gold particles (110 to 270 Åin diameter) were injected, nuclear uptake was significantly greater in proliferating as compared to quiescent cells. The average fonctional pore diameter was approximately 230 Å during proliferation, and 140 Åor less in quiescent populations.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

Tissue Ki67 proliferative index expression and pathological changes in hemodialysis arteriovenous fistulae: Preliminary single-center results

2021 ◽  
pp. 112972982110154
Author(s):  
Raffaella Mauro ◽  
Cristina Rocchi ◽  
Francesco Vasuri ◽  
Alessia Pini ◽  
Anna Laura Croci Chiocchini ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Hot Spot ◽  
Wall Thickening ◽  
Proliferating Cells ◽  
Ki 67 ◽  
Group A ◽  
The Mean ◽  
Set Up ◽  
Group B

Background: Arteriovenous fistula (AVF) for hemodialysis integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes. Aim of this study is to determine the role of Ki67, a well-established proliferative marker, related to AVF, and its relationship with time-dependent histological morphologic changes. Materials and methods: All patients were enrolled in 1 year and stratified in two groups: (A) pre-dialysis patients submitted to first AVF and (B) patients submitted to revision of AVF. Morphological changes: neo-angiogenesis (NAG), myointimal thickening (MIT), inflammatory infiltrate (IT), and aneurysmatic fistula degeneration (AD). The time of AVF creation was recorded. A biopsy of native vein in Group A and of arterialized vein in Group B was submitted to histological and immunohistochemical (IHC) analysis. IHC for Ki67 was automatically performed in all specimens. Ki67 immunoreactivity was assessed as the mean number of positive cells on several high-power fields, counted in the hot spots. Results: A total of 138 patients were enrolled, 69 (50.0%) Group A and 69 (50.0%) Group B. No NAG or MIT were found in Group A. Seven (10.1%) Group A veins showed a mild MIT. Analyzing the Group B, a moderate-to-severe MIT was present in 35 (50.7%), IT in 19 (27.5%), NAG in 37 (53.6%); AD was present in 10 (14.5%). All AVF of Group B with the exception of one (1.4%) showed a positivity for Ki67, with a mean of 12.31 ± 13.79 positive cells/hot spot (range 0–65). Ki67-immunoreactive cells had a subendothelial localization in 23 (33.3%) cases, a myointimal localization in SMC in 35 (50.7%) cases. The number of positive cells was significantly correlated with subendothelial localization of Ki67 ( p = 0.001) and with NA ( p = 0.001). Conclusions: Native veins do not contain cycling cells. In contrast, vascular cell proliferation starts immediately after AVF creation and persists independently of the time the fistula is set up. The amount of proliferating cells is significantly associated with MIT and subendothelial localization of Ki67-immunoreactive cells, thus suggesting a role of Ki-67 index in predicting AVF failure.

scholarly journals Evaluating the Effects of Sediment Transport on Pipe Flow Resistance

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2091
Author(s):  
Vito Ferro ◽  
Alessio Nicosia
Keyword(s):  
Velocity Profile ◽  
Pipe Flow ◽  
Power Distribution ◽  
Flow Resistance ◽  
Unit Length ◽  
Particle Diameter ◽  
Self Similarity ◽  
Sediment Size ◽  
The Mean ◽  
The Relationship

In this paper, the applicability of a theoretical flow resistance law to sediment-laden flow in pipes is tested. At first, the incomplete self-similarity (ISS) theory is applied to deduce the velocity profile and the corresponding flow resistance law. Then the available database of measurements carried out by clear water and sediment-laden flows with sediments having a quasi-uniform sediment size and three different values of the mean particle diameter Dm (0.88 mm, 0.41 mm and 0.30 mm) are used to calibrate the parameter of the power-velocity profile). The fitting of the measured local velocity to the power distribution demonstrates that (i) for clear flow the exponent δ) can be estimated by the equation of Castaing et al. and (ii) for the sediment-laden flows δ is related to the diameter Dm. A relationship for estimating the parameter Гv obtained by the power-velocity profile) and that Гf of the flow resistance law) is theoretically deduced. The relationship between the parameter Гv, the head loss per unit length and the pipe flow Froude number is also obtained by the available sediment-laden pipe flow data. Finally, the procedure to estimate the Darcy–Weisbach friction factor is tested by the available measurements.

scholarly journals Evaluation of Atrial Natriuretic Peptide and Brain Natriuretic Peptide in Atrial Granules of Rats with Experimental Congestive Heart Failure

2001 ◽  
Vol 49 (10) ◽  
pp. 1293-1300 ◽  
Author(s):  
Gad M. Bialik ◽  
Zaid A. Abassi ◽  
Ilan Hammel ◽  
Joseph Winaver ◽  
Dina Lewinson
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Atrial Natriuretic Peptide ◽  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Aortocaval Fistula ◽  
Granule Formation ◽  
Gold Particles ◽  
The Mean ◽  
Atrial Natriuretic

The natriuretic peptides are believed to play an important role in the pathophysiology of congestive heart failure (CHF). We utilized a quantitative cytomorphometric method, using double immunocytochemical labeling, to assess the characteristics of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in atrial granules in an experimental model of rats with CHF induced by aortocaval fistula. Rats with CHF were further divided into decompensated (sodium-retaining) and compensated (sodium-excreting) subgroups and compared with a sham-operated control group. A total of 947 granules in myocytes in the right atrium were analyzed, using electron microscopy and a computerized analysis system. Decompensated CHF was associated with alterations in the modal nature of granule content packing, as depicted by moving bin analysis, and in the granule density of both peptides. In control rats, the mean density of gold particles attached to both peptides was 347.0 ± 103.6 and 306.3 ± 89.9 gold particles/μm2 for ANP and BNP, respectively. Similar mean density was revealed in the compensated rats (390.6 ± 81.0 and 351.3 ± 62.1 gold particles/μm2 for ANP and BNP, respectively). However, in rats with decompensated CHF, a significant decrease in the mean density of gold particles was observed (141.6 ± 67.3 and 158.0 ± 71.2 gold particles/μm2 for ANP and BNP, respectively; p < 0.05 compared with compensated rats, for both ANP and BNP). The ANP:BNP ratio did not differ between groups. These findings indicate that the development of decompensated CHF in rats with aortocaval fistula is associated with a marked decrease in the density of both peptides in atrial granules, as well as in alterations in the quantal nature of granule formation. The data further suggest that both peptides, ANP and BNP, may be regulated in the atrium by a common secretory mechanism in CHF.

scholarly journals The Micro-Geometry Evaluation on Steel Sheets after Chemical Surface Treatment

2013 ◽  
Vol 10 (2) ◽  
pp. 22-25
Author(s):  
Dagmar Draganovská ◽  
Miroslav Tomáš ◽  
Peter Ižol
Keyword(s):  
Surface Treatment ◽  
Steel Sheet ◽  
Unit Length ◽  
Mean Deviation ◽  
Maximum Height ◽  
Chemical Surface ◽  
Steel Sheets ◽  
Mean Width ◽  
The Mean ◽  
Metal Materials

Abstract The protection of metal materials by coatings is one of the most important way to protect the surface against corrosion. Galvanisation of metal surfaces by an electric current is one of the most frequent way of surface treatment due to its wide application. The paper is oriented to the evaluation of the surface quality in terms of micro-geometry. The basic surface of the steel sheet S235JRG2 has been evaluted and compared to the degreased one, galvanized one and surface after galvanizing, chromatizing and phosphating. The microgeometry parameters such as the arithmetical mean deviation Ra, the maximum height of profile Rz, the total height of profile Rt as well as the the mean width of the profile elements RSm and the number of peaks per unit length RPc has been compared.

Regulation of functional nuclear pore size in fibroblasts

2001 ◽  
Vol 114 (24) ◽  
pp. 4621-4627
Author(s):  
Carl M. Feldherr ◽  
Debra Akin ◽  
Robert J. Cohen
Keyword(s):  
Pore Size ◽  
Transcriptional Activation ◽  
Pore Diameter ◽  
Nuclear Transport ◽  
Control Level ◽  
Proteasome Inhibitors ◽  
Nuclear Pore ◽  
Transport Capacity ◽  
3T3 Cells ◽  
Gold Particles

Protein-NLS-coated gold particles up to approximately 250 Å in diameter are transported through the nuclear pores in normal, proliferating BALB/c 3T3 cells. This size can increase or decrease, depending on cellular activity. It has been suggested that increases in functional pore size are related to a reduction in the amount of available p53. To further test this hypothesis, we investigated the effects of cycloheximide and pifithrin-α, which inhibits p53-dependent transcriptional activation, on nuclear transport. After 3 hours in cycloheximide, there was a significant increase in the size of the gold particles that entered the nucleoplasm. When the incubation period was extended to 6 hours or longer, transport capacity returned to the control level. By using proteasome inhibitors, it was shown that the cycloheximide-dependent increase in functional pore size was due to the inhibition of protein synthesis, consistent with the fact that p53 is a short-lived protein, and requires the activity of at least two different factors. Although cycloheximide increases the functional diameter of the channel available for signal-mediated transport by approximately 60 Å, it had no significant effect on either the import rate of small NLS-containing substrates (FITC-BSA-NLS), or passive diffusion of fluorescent-labeled proteins across the envelope. This suggests that changes in transport capacity were not caused by an increase in overall pore diameter but instead are due to a transient increase in pore size that accompanies signal-mediated transport. Pifithrin-α also caused an increase in functional pore diameter without altering the import rate of FITC-BSA-NLS, providing further support for the view that p53 can initiate changes in nuclear transport capacity.

How Recyclability can Reduce Induction Period of Gold Nanocatalysts

2019 ◽  
Vol 57 ◽  
pp. 1-6 ◽  
Author(s):  
Sedigheh Ghadamgahi
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Gold Particle ◽  
Particle Diameter ◽  
Gold Catalysts ◽  
Gold Particles ◽  
Transmission Electron ◽  
The Mean ◽  
Full Conversion ◽  
Catalytic Test

The effect of recyclability on the catalytic activity of supported Au101(PPh3)21Cl5 nanoparticles (1.0 wt% Au101/AC) was investigated for benzyl alcohol oxidation under mild conditions. The influence of recyclability on the catalytic activity of activated Au101/AC nanocatalysts was studied trough a comparison of gold particle diameter and also catalysts conversion between the fresh (as synthesized) and recycled gold catalysts. The monitoring of gold particle diameters by transmission electron microscopy (TEM) showed that the gold particles size gradually increased during the catalytic reaction. The mean diameter of the fresh gold catalysts increased from approximately 3 to 3.2, 5.1 and 5.3 nm after 1, 2 and 3 h reaction time, respectively. Whereas the average gold particle diameter of the recycled samples were slightly enlarged from approximately 5.3 (the sample recycled after 3 h of the first catalytic test) to 5.7, 5.9 and 6.2 nm with durations of 1, 2 and 3 h reaction time, respectively. Therefore, larger gold particles gradually formed for fresh and also recycled gold catalysts during reaction tests. Meanwhile, the catalytic activity of activated 1.0 wt% Au101/AC catalysts jumped to full conversion when the recycled gold catalysts were utilized due to removing ligand stabilizer from gold particles and so bigger particles had formed.

How to Increase the Burden on Trauma Centers: Implement the 80-hour Work Week

2014 ◽  
Vol 80 (7) ◽  
pp. 659-663
Author(s):  
Thomas J. Schroeppel ◽  
John P. Sharpe ◽  
Louis J. Magnotti ◽  
Jordan A. Weinberg ◽  
Martin A. Croce ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Length Of Stay ◽  
Injury Severity ◽  
Trauma Registry ◽  
Unit Length ◽  
Work Hours ◽  
Trauma Centers ◽  
Adjusted Analysis ◽  
The Mean ◽  
Post Period

The 80-hour week was implemented in 2003 to improve outcomes and limit errors. We hypothesize that there has been no change in outcomes postimplementation of the restrictions. Outcomes were queried from the trauma registry from 1997 to 2002 (PRE) and 2004 to 2009 (POST). Primary outcomes were mortality, intensive care unit length of stay (ICU LOS), and length of stay (LOS). Patients were stratified based on demographics, blood pressure, heart rate, and injury severity (Injury Severity Score, Glasgow Coma Score, base deficit). Outcomes were then compared PRE with POST. A total of 41,770 patients were admitted during the study period. The mean age was 38 years with most being male (73%) and blunt mechanism (78%). Although patients admitted in the POST period had a slightly higher blood pressure, they were older and had higher injury severity. ICU LOS, LOS, self-pay, and mortality were higher in the POST period. After adjusted analysis, admission in the POST period was no longer a predictor of mortality (odds ratio, 1.02; confidence interval, 0.92 to 1.14). Whereas patients were more slightly more injured in the POST period, the adjusted analysis shows no difference in mortality and both a longer LOS and ICU LOS. Whether the increase is the result of more severe injury in the POST period or less efficient disposition remains to be elucidated. This study adds to the mounting evidence that the implementation of the limits on work hours does not lead to better outcomes.

scholarly journals The GLUT5 hexose transporter is also localized to the basolateral membrane of the human jejunum

1995 ◽  
Vol 309 (1) ◽  
pp. 7-12 ◽  
Author(s):  
S J Blakemore ◽  
J C Aledo ◽  
J James ◽  
F C Campbell ◽  
J M Lucocq ◽  
...  
Keyword(s):  
Phosphatase Activity ◽  
Unit Length ◽  
Basolateral Membrane ◽  
Basal Membrane ◽  
Morphological Evidence ◽  
Hexose Transporter ◽  
Gold Particles ◽  
Quantitative Analyses ◽  
Gold Labelling ◽  
Quantitative Immunoblotting

The intestine is a major site of expression of the human GLUT5 hexose transporter, which is thought to be localized exclusively to the brush border membrane (BBM) where its major role is likely to be in the absorption of fructose. In this study we present novel biochemical and morphological evidence showing that the GLUT5 transporter is also expressed in the basolateral membrane (BLM) of the human intestine. BBM and BLM were isolated by fractionation of human jejunum. BBM were enriched with alkaline phosphatase activity by over 9-fold relative to a crude jejunal homogenate and contained immunoreactive sucrase-isomaltase and GLUT5 proteins. By contrast the BBM fraction was substantially depleted of immunoreactive a1 subunits of the Na,K-ATPase and GLUT2 glucose transporters which were abundantly present in the BLM fraction. This BLM fraction was enriched by over 11-fold in potassium-stimulated phosphatase activity relative to the crude homogenate; BLM also reacted to immunological probes for GLUT5 but showed no observable reactivity with antibodies directed against sucrase-isomaltase. Quantitative immunoblotting revealed that the BBM and BLM contained near equal amounts of GLUT5 per mg of membrane protein. Immunogold localization of GLUT5 on ultrathin sections of human jejunum showed that GLUT5 was present in both apical BBM and BLM. This gold labelling was absent when antiserum was pre-incubated with the antigenic peptide corresponding to a specific C-terminal sequence of human GLUT5. Quantitative analyses of the number of gold particles per unit length of BBM and BLM indicated that the mean density of gold labelling was marginally greater in the BBM (0.399 gold particles/micrometer) than in the BLM (0.293 gold particle/micrometer). The localization of GLUT5 in the BLM of the human jejunum may suggest that it specifically participates in the transfer of fructose across the basal membrane of the enterocyte.

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