Validation of a specific radioimmunoassay to measure plasma cortisol in the fetal sheep.

A procedure utilizing co-chromatography and complementary antiserum comparisons was employed to assess the specificity of a cortisol radioimmunoassay for use in the chronically catheterized fetal sheep preparation. Complementary antiserum comparisons is a technique by which two different cortisol antisera, prepared from conjugates attached at opposite ends of the cortisol molecule, were used to determine cortisol concentrations in the same ovine fetal plasma specimens. Results were not significantly different between the two groups, each measured by a different antiserum. This procedure may be used to assess assay specificity in any species in which steroid radioimmunoassays are being adapted.     

Spatiotemporal variation of leaf epidermal cell growth: a quantitative analysis of Arabidopsis thaliana wild-type and triple cyclinD3 mutant plants

Background and Aims

The epidermis of an expanding dicot leaf is a mosaic of cells differing in identity, size and differentiation stage. Here hypotheses are tested that in such a cell mosaic growth is heterogeneous and changes with time, and that this heterogeneity is not dependent on the cell cycle regulation per se.

Methods

Shape, size and growth of individual cells were followed with the aid of sequential replicas in expanding leaves of wild-type Arabidopsis thaliana and triple cyclinD3 mutant plants, and combined with ploidy estimation using epi-fluorescence microscopy.

Key Results

Relative growth rates in area of individual epidermal cells or small cell groups differ several fold from those of adjacent cells, and change in time. This spatial and temporal variation is not related to the size of either the cell or the nucleus. Shape changes and growth within an individual cell are also heterogeneous: anticlinal wall waviness appears at different times in different wall portions; portions of the cell periphery in contact with different neighbours grow with different rates. This variation is not related to cell growth anisotropy. The heterogeneity is typical for both the wild type and cycD3.

Conclusions

Growth of leaf epidermis exhibits spatiotemporal variability.     

Immunohistochemical characterization of neoplastic cells of breast origin

ABSTRACT: BACKGROUND: After skin cancer, breast cancer is the most common malignancy in women. Tumors of unknown origin account for 5-15% of malignant neoplasms, with 1.5% corresponding to breast cancer. We selected an immunohistochemical panel with conventional and newer markers, such as mammaglobin, for the detection of neoplastic cells of breast origin. The specific objectives are: 1) to determine the sensitivity and specificity of the panel, with an especial emphasis on the inclusion of the mammaglobin marker, and 2) to compare immunohistochemistry performed on whole tissue sections and on Tissue Micro-Array. Methods. Twenty-nine metastatic breast tumors were included and assumed as tumors of unknown origin. Other 48 biopsies of other tissues were selected and assumed as negative controls. Tissue Micro-Array was performed. Immunohistochemistry for mammaglobin, gross cystic disease fluid protein-15, estrogen receptor, progesterone receptor and cytokeratin 7 was done. Results. Mammaglobin positive staining was observed in 10/29 cases, in 13/29 cases for gross cystic disease fluid protein-15, in 20/29 cases for estrogen receptor, 9/29 cases for progesterone receptor, and in 25/29 cases for cytokeratin 7. Among the negative controls, mammaglobin was positive in 2/48, and gross cystic disease fluid protein-15 in 4/48. Conclusions. The inclusion of MAG antibody in the immunohistochemical panel for the detection of tumors of unknown origin increased the probability of detecting metastasis of breast cancer. For the diagnostic strategy with the highest positive predictive value (87.5%), hormone receptors and mammaglobin were considered in serial, non-parallel manner.     

PH-dependent changes of 2,3-bisphosphoglycerate in human red cells during transitional and steady states in vitro.

A systematic study of the pH-dependent changes in the range 6.6--7.4 of 2,3-bisphosphoglycerate and the adenine nucleotides was performed in the presence and absence of glucose during transitional and steady states. 1. The results indicatethat 2,3-gisphosphoglycerate phosphatase breaks down 2,3-bisphosphoglycerate nearly independent of pH at a rate of 480 mumol 2,3-bisphosphoglycerate x1 cells-1xh-1.2,3-Bisphosphoglycerate mutase is practically completely inhibited below pH value increases in long-term experiments with lower 2,3-bisphosphoglycerate levels. The formation of pyruvate corresponds to the breakdown of 2,3-bisphosphoglycerate afterconsumption of an unknown reducing substance.     

A specific fluorescence probe for hydrogen peroxide detection in peroxisomes

Hydrogen peroxide is an important mediator in cell signalling and cell death. Apart from the mitochondrion the peroxisome is the most important cellular site for the generation and scavenging of hydrogen peroxide. Peroxisomes contain various oxidases, e.g. for the metabolism of long-chain fatty acids, polyamines, and for the oxidation of urate, which form hydrogen peroxide. Widely-used chemical probes for the detection of hydrogen peroxide like dichlorofluorescein diacetate (DCFDA) often lack in specificity and the possibility of compartment-specific measurement. To overcome these disadvantages, Belousov et al. developed the novel hydrogen peroxide sensitive fluorescent protein HyPer. In the present study the HyPer protein was fused with the PTS1 tag for a specific hydrogen peroxide detection in peroxisomes. The localization of the HyPer protein in the peroxisomes was confirmed by immunofluorescence and the functionality by fluorescence microscopy and flow cytometry analyses. The presented HyPer-Peroxi fluorescent protein is a valuable tool for studying hydrogen peroxide generation within the peroxisomes.     

Alien parasitic copepods in mussels and oysters of the Wadden Sea

Molluscan intestinal parasites of the genus Mytilicola, specifically M. intestinalis, were initially introduced into bivalves in the North Sea in the 1930s. It was presumably introduced from the Mediterranean with ship-fouling mussels, then attained epidemic proportions in Mytilus edulis in the 1950s and is now widely established in the North Sea region. Mytilicola orientalis was co-introduced with Pacific oysters to France in the 1970s and in the southern North Sea in the early 1990s. Its main host Crassostrea gigas has massively invaded the Wadden Sea with a concomitant decline in mussels. To explore whether introduced mytilicolid parasites could play a role in the shifting dominance from native mussels to invasive oysters, we analysed 390 mussels and 174 oysters collected around the island of Sylt in the northern Wadden Sea. We show that M. intestinalis has a prevalence >90% and a mean intensity of 4 adult copepods in individual mussels with >50 mm shell length at all sheltered sites. By contrast, none were found in the oysters. However, at one site, we found M. orientalis in C. gigas with a prevalence of 10% and an intensity of 2 per host individual (August 2008). This constitutes the most northern record in Europe for this Pacific parasite until now. Alignments of partial sequences of the mitochondrial cytochrome oxidase I (COI) gene and the nuclear internal transcribed spacers (ITS) and 18S rDNA sequences each show a distinct difference between the two species, which confirms our morphological identification. We suggest that the high parasite load in mussels compared to oysters may benefit the continued expansion of C. gigas in the Wadden Sea.     

Intrinsic potential for immediate biodegradation of toluene in a pristine,energy-limited aquifer

Pristine and energy-limited aquifers are considered to have a low resistance and resilience towards organic pollution. An experiment in an indoor aquifer system revealed an unexpected high intrinsic potential for the attenuation of a short-term toluene contamination. A 30 h pulse of 486 mg of toluene, used as a model contaminant, and deuterated water (D₂O) through an initially pristine, oxic, and organic carbon poor sandy aquifer revealed an immediate aerobic toluene degradation potential. Based on contaminant and tracer break-through curves, as well as mass balance analyses and reactive transport modelling, a contaminant removal of 40 % over a transport distance of only 4.2 m in less than one week of travel time was obtained. The mean first-order degradation rate constant was λ = 0.178 day^?1, corresponding to a half-life time constant T_1/2 of 3.87 days. Toluene-specific stable carbon isotope analysis independently proved that the contaminant mass removal can be attributed to microbial biodegradation. Since average doubling times of indigenous bacterial communities were in the range of months to years, the aerobic biodegradation potential observed is assumed to be present and active in the pristine, energy-limited groundwater ecosystems at any time. Follow-up experiments and field studies will help to quantify the immediate natural attenuation potential of aquifers for selected priority contaminants and will try to identify the key-degraders within the autochthonous microbial communities.     

Tornado Intensity Estimated from Damage Path Dimensions

The Newcastle/Moore and El Reno tornadoes of May 2013 are recent reminders of the destructive power of tornadoes. A direct estimate of a tornado''s power is difficult and dangerous to get. An indirect estimate on a categorical scale is available from a post-storm survery of the damage. Wind speed bounds are attached to the scale, but the scale is not adequate for analyzing trends in tornado intensity separate from trends in tornado frequency. Here tornado intensity on a continuum is estimated from damage path length and width, which are measured on continuous scales and correlated to the EF rating. The wind speeds on the EF scale are treated as interval censored data and regressed onto the path dimensions and fatalities. The regression model indicates a 25% increase in expected intensity over a threshold intensity of 29 m s⁻¹ for a 100 km increase in path length and a 17% increase in expected intensity for a one km increase in path width. The model shows a 43% increase in the expected intensity when fatalities are observed controlling for path dimensions. The estimated wind speeds correlate at a level of .77 (.34, .93) [95% confidence interval] with a small sample of wind speeds estimated independently from a doppler radar calibration. The estimated wind speeds allow analyses to be done on the tornado database that are not possible with the categorical scale. The modeled intensities can be used in climatology and in environmental and engineering applications. Research is needed to understand the upward trends in path length and width.