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71.
Fixation in 10% neutral buffered formalin prior to transfer to 70% ethanol for one week has been shown to adequately preserve immunorecognition of PCNA, cytokeratins AE1/AE3 and EGFr. This study investigated whether 12 hrs fixation in 10% NBF plus transfer to 70% ethanol for 4 weeks would similarly preserve immunorecognition to an extent where antigen retrieval (AR) used to reverse the masking effects of fixation on some antigens would not be necessary. Two cell lines, DU145 and SKOV3 were grown on coverslips and fixed either for 684 hrs in 10% NBF or for 12 hrs in 10% NBF which was then replaced with 70% ethanol for 672 hrs. The second experiment had the same design except an additional set of cells were subjected to heat-induced AR concomitantly. PCNA, cytokeratins AE1/AE3, and EGFr (membrane and cytoplasmic) were used to evaluate the effects of immunorecognition. Fixation in 10% NBF for 12 hrs plus transfer to 70% ethanol for 672 hrs did not preserve immunorecognition of PCNA adequately in either cell lines. Cytokeratins immunoreactivity was preserved by transfer to 70% ethanol. Cytoplasmic EGFr antigens were not adversely affected by 10% NBF fixation in either cell line and transfer to 70% ethanol had limited effects. With AR, there was little recovery of PCNA immunorecognition on cells fixed in only 10% NBF, but almost complete recovery for cells transferred to 70% ethanol. For cytokeratins there was complete recovery of immunorecognition either with only 10% NBF or 12 hrs plus transfer to 70% ethanol. For EGFr, AR resulted in complete loss of immunorecognition following either treatment. This study indicated that 12 hrs of fixation in 10% NBF plus transfer to 70% ethanol for 4 weeks with AR resulted in recovery of immunorecognition for PCNA and cytokeratins, but standard methods of AR caused loss of immunorecognition of EGFr. 相似文献
72.
Kim H Folks KD Guo L Sellers JC Fineberg NS Stockard CR Grizzle WE Buchsbaum DJ Morgan DE George JF Zinn KR 《Molecular imaging》2011,10(3):153-167
Early pancreatic cancer response following cetuximab and/or irinotecan therapies was measured by serial dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) before and during therapy. Groups 1 to 4 (n = 6/group) of SCID mice bearing orthotopic pancreatic adenocarcinoma xenografts expressing luciferase were treated with phosphate-buffered saline, cetuximab, irinotecan, or cetuximab combined with irinotecan, respectively, twice weekly for 3 weeks. DCE-MRI was performed on days 0, 1, 2, and 3 after therapy initiation, whereas anatomic magnetic resonance imaging was performed on days 0, 1, 2, 3, 6, and 13. Bioluminescence imaging was performed on days 0 and 21. At day 21, all tumors were collected for further histologic analyses (Ki-67 and CD31 staining), whereas tumor dimensions were measured by calipers. The Ktrans values in the 0.5 mm-thick peripheral tumor region were calculated, and the changes in Ktrans during the 3 days posttherapy were compared to tumor volume changes, bioluminescent signal changes, and histologic findings. The Ktrans changes in the peripheral tumor region after 3 days of therapy were linearly correlated with 21-day decreases in tumor volume (p < .001), bioluminescent signal (p = .050), microvessel densities (p = .002), and proliferating cell densities (p = .001). This study supports the clinical use of DCE-MRI for pancreatic cancer patients for early assessment of an anti-epidermal growth factor receptor therapy combined with chemotherapy. 相似文献
73.
Smad4 as a transcription corepressor for estrogen receptor alpha 总被引:7,自引:0,他引:7
74.
Sulfation of fucoidin in focus embryos: III. Required for localization in the rhizoid wall 下载免费PDF全文
Zygotes of the brown alga Fucus distichus L. Powell accumulate a sulfated polysaccharide (fucoidin) in the cell wall at the site of rhizoid formation. Previous work indicated that zygotes grown in seawater minus sulfate do not sulfate the preformed fucan (an unsulfated fucoidin) but form rhizoids. Under these conditions, we determined whether sulfation of the fucan is required for its localization in the rhizoid wall. This was accomplished by developing a specific stain for both the fucan and fucoidin. Using a precipitin assay, we demonstrated in vitro that the lectin ricin (RCA(I)) specifically complexes with both the sulfated and desulfated polysaccharide. No precipitate is observed when either is incubated in 0.1 M D-galactose or when RCA(I) is mixed with laminarin or alginic acid, the other major polysaccharides in Fucus. RCA(I) conjugated with fluorescein isothiocyanate (FITC) is also shown to bind specifically to fucoidin using a filter paper (DE81) assay. When added to zygotes, RCA(I)-FITC binds only to the site of fucoidin localization, i.e., the rhizoid cell wall. However, RCA(I)-FITC is not observed in the rhizoid wall of zygotes grown in the absence of sulfate. This observation is not due to inability of RCA(I)-FITC to bind to the fucan in vivo. Chemically desulfated cell walls that contained fucoidin in the rhizoid wall bind RCA(I)-FITC only in the rhizoid region. Also, the concentration of fucose-containing polymers and polysaccharides that form precipitates with RCA(I) is the same in embryos grown in the presence or absence of sulfate. If sulfate is added back to cultures of zygotes grown without sulfate, fucoidin is detected at the rhizoid tip by RCA(I)-FITC several hours later. These results support the conclusion that the enzymatic sulfation of the fucan is a modification of the polysaccharide required for its localization and/or assembly into a specific region of the cell wall. 相似文献
75.
Light and electron microscopic examination of fathead minnow head kidneys revealed that the interrenal and chromaffin cells were intermingled and always closely associated with the cardinal veins and their tributaries. Histochemical tests for lipids in the interrenal cells were positive, and two types of chromaffin cells were indicated by chromaffin reactions. Interrenal cells contained abundant smooth endoplasmic reticulum and mitochondria with tubulo-vesicular cristae, characteristic of steroid-producing cells. Only one interrenal cell type was found. Two types of chromaffin cells were present with differences in cytoplasmic density and in types of granules. In light cells, adrenaline granules were most common, and in dark cells noradrenaline granules predominated. 相似文献
76.
Samples of grain from three spring barley cultivars of differing malting quality were collected at regular intervals during four weeks prior to harvest. The samples were dried, then assessed for relative grain hardness using the "Milling Energy" test. Ranking order of the cultivars for this character, which relates strongly to malting quality, was unaltered throughout. In a further experiment, it was demonstrated that selection for milling energy could be successfully practised on oven-dried grain collected six weeks after ear emergence. 相似文献
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Soil Microbial Community Response to Drought and Precipitation Variability in the Chihuahuan Desert 总被引:2,自引:0,他引:2
Jeb S. Clark James H. Campbell Heath Grizzle Veronica Acosta-Martìnez John C. Zak 《Microbial ecology》2009,57(2):248-260
Increases in the magnitude and variability of precipitation events have been predicted for the Chihuahuan Desert region of
West Texas. As patterns of moisture inputs and amounts change, soil microbial communities will respond to these alterations
in soil moisture windows. In this study, we examined the soil microbial community structure within three vegetation zones
along the Pine Canyon Watershed, an elevation and vegetation gradient in Big Bend National Park, Chihuahuan Desert. Soil samples
at each site were obtained in mid-winter (January) and in mid-summer (August) for 2 years to capture a component of the variability
in soil temperature and moisture that can occur seasonally and between years along this watershed. Precipitation patterns
and amounts differed substantially between years with a drought characterizing most of the second year. Soils were collected
during the drought period and following a large rainfall event and compared to soil samples collected during a relatively
average season. Structural changes within microbial community in response to site, season, and precipitation patterns were
evaluated using fatty acid methyl ester (FAME) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE)
analyses. Fungal FAME amounts differed significantly across seasons and sites and greatly outweighed the quantity of bacterial
and actinomycete FAME levels for all sites and seasons. The highest fungal FAME levels were obtained in the low desert scrub
site and not from the high elevation oak–pine forests. Total bacterial and actinomycete FAME levels did not differ significantly
across season and year within any of the three locations along the watershed. Total bacterial and actinomycete FAME levels
in the low elevation desert-shrub and grassland sites were slightly higher in the winter than in the summer. Microbial community
structure at the high elevation oak–pine forest site was strongly correlated with levels of NH4
+–N, % soil moisture, and amounts of soil organic matter irrespective of season. Microbial community structure at the low elevation
desert scrub and sotol grasslands sites was most strongly related to soil pH with bacterial and actinobacterial FAME levels
accounting for site differences along the gradient. DGGE band counts of amplified soil bacterial DNA were found to differ
significantly across sites and season with the highest band counts found in the mid-elevation grassland site. The least number
of bands was observed in the high elevation oak–pine forest following the large summer-rain event that occurred after a prolonged
drought. Microbial responses to changes in precipitation frequency and amount due to climate change will differ among vegetation
zones along this Chihuahuan Desert watershed gradient. Soil bacterial communities at the mid-elevation grasslands site are
the most vulnerable to changes in precipitation frequency and timing, while fungal community structure is most vulnerable
in the low desert scrub site. The differential susceptibility of the microbial communities to changes in precipitation amounts
along the elevation gradient reflects the interactive effects of the soil moisture window duration following a precipitation
event and differences in soil heat loads. Amounts and types of carbon inputs may not be as important in regulating microbial
structure among vegetation zones within in an arid environment as is the seasonal pattern of soil moisture and the soil heat
load profile that characterizes the location. 相似文献