Uptake, accumulation and phytoextraction efficiency of cesium in Gypsophila paniculata.

To evaluate the phytoextraction efficiency of Gypsophila paniculata from Cs-contaminated soils and analyze the mechanism of Cs accumulation in G. paniculata, we analyzed the characteristics of Cs bioaccumulation and subcellular distribution, in addition to its chemical forms in the plant under hydroponic conditions. The results showed that total Cs content in the aboveground parts and the entire plant were as high as 6137.32 mg·kg-1 dry weight and 7338.49 mg·kg-1 dry weight, respectively, after 17 days in the 50 mg·L-1 Cs treatment. The BCF was between 2.35 and 3.38. The TF was between 1.00 and 2.46 in G. paniculata. Subcellular distribution of Cs in the plant was as follows: soluble fraction > cell wall > organelles. Inorganic Cs (F-ethanol) and water-soluble Cs (F-dH2O) were the main types of Cs in G. paniculata. Further studies show that the phytoextraction efficiency can reach 10.30-11.91% planting a season of G. paniculata under potted conditions. The results suggested that G. paniculata, a perennial, drought-tolerant herb, was a high-accumulator of Cs, which may have potential uses in phytoremediation of Cs-contaminated soil.

[Hydrochemical and Stable Isotopic Characteristics and Transformation Relationship of Water Bodies in the Guohe River Basin, Anhui Province].

The Guohe River Basin in Anhui Province was selected as the research area for this study. By collecting surface water, shallow groundwater, and middle-deep groundwater samples, various hydrochemical parameters and stable isotopes of water in different water bodies were analyzed using methods such as the Gibbs diagram, ion ratios, and MixSIAR model to reveal and quantify the transformation relationships between these water bodies. The results indicated that both surface water and groundwater in the study area were predominantly neutral to weakly alkaline. The hydrochemical types of surface water were mainly characterized by Cl·SO4·HCO3-Na and Cl·SO4-Na types, whereas the shallow groundwater exhibited HCO3-Ca·Mg and HCO3-Mg·Na types, and the middle-deep groundwater was of the Cl·HCO3-Na type. The hydrochemical characteristics of various water bodies were influenced by multiple factors such as rock weathering, evaporation concentration, and positive cation exchange. The distribution characteristics of δ18O and δ2H values in surface water and groundwater indicated that atmospheric precipitation was the main water source. The δ18O and δ2H in groundwater were significantly correlated with K+, Na+, Cl-, SO42-, and NO3-. According to the analysis using the MixSIAR model, the contribution of atmospheric precipitation to surface water was 46.5 %, whereas the contribution from shallow groundwater was 53.5 %. The sources of shallow groundwater were identified as atmospheric precipitation (57.4 %) and surface water (42.6 %), and the main source of supply for middle-deep groundwater was lateral flow from upstream groundwater.

[The spectrum studies of structure characteristics in magma contact metamorphic coal].

The structural parameters evolution of coal due to the influence of intrusions of hot magma was investigated and analyzed. X-ray diffraction and laser confocal microscope Raman spectroscopy were used to test and analyze 4 coal samples undergoing varying contact-metamorphism by igneous magmas in borehole No. 13-4 of Zhuji coal mine, Huainan coalfield. The result showed that coal XRD spectrum showed higher background intensity, with the 26 degrees and 42 degrees nearby apparent graphite diffraction peak. Two significant vibration peaks of coal Raman spectra were observed in the 1 000-2 000 cm(-1) frequency range: broad "D" peak at 1 328-1 369 cm(-1) and sharp "G" peak at 1 564-1 599 cm(-1). With the influence of magma intrusion, the relationship between coal structural parameters and coal ranks was excellent.

Spatial distribution characteristics and prediction of fluorine concentration in groundwater based on driving factors analysis.

Excess fluoride (F-) in groundwater can be hazardous to human health. A total of 360 ground water samples was collected from northern Anhui, China, to study the levels, distribution, and source of F-. And on this basis, predicting the spatial distribution of F- in a wider scale space. The range of F- was 0.1-5.8 mg/L, with a mean value of 1.2 mg/L, and 26.4 % of the samples exceeded the acceptable level of 1.5 mg/L. Moreover, the water-rock interaction (fluorite dissolution) and cation alternate adsorption were considered to be two main driving factors of high F- in groundwater. To further illustrate the spatial effects, the BME-RF model was established by combining the main environmental factors. The spatial distribution of F- was quantitatively predicted, and the response to environmental variables was analyzed. The R2 of BME-RF model reached 0.93, the prediction results showed that the region with 1.0-1.5 mg/L of F- accounts for 47.2 % of the total area. The predicted F- content of nearly 70 % of groundwater in this area has exceeded 1.0 mg/L, which was dominated by Na+ and HCO3- type. The spatial variability of F- in the study area was mainly affected by hydrogeological conditions, and the vertical distribution characteristics were related to the spatial variation of slope, distance from runoff, and hydrochemical types. The results of the study provide new insights into the F- concentration prediction in underground environment, especially in the borehole gap area.

Identification of nitrate sources in Taihu Lake and its major inflow rivers in China, using δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) values.

In the present study, δ(15)N and δ(18)O-NO(3)(-) values, as well as concentrations of some major ion tracers were determined in seasonal water samples from Taihu Lake and major watersheds to investigate the temporal and spatial variations of nitrate sources and assess the underlying nitrogen (N) biogeochemistry process. The results lead to the conclusion that the nitrate concentrations in Taihu Lake are lower in summer than that in winter due to the dilution effect of wet deposition. In winter, sewage and manure were the primary nitrate sources in major inflow rivers and North Taihu Lake (NTL), while nitrate sources in East Taihu Lake (ETL) probably derived from soil organic N. In summer, atmospheric deposition and sewage/manure inputs appear to play an important role in controlling the distribution of nitrates in the whole lake. The δ(18)O-NO(3)(-) values suggest that the nitrate produced from microbial nitrification is another major nitrate source during both winter and summer months. The variations in isotopic values in nitrate suggest denitrification enriched the heavier isotopes of nitrate in NTL in winter and in ETL in summer.

[Spatial Distribution and Pollution Assessment of Dissolved Heavy Metals in Chaohu Lake Basin During the Wet Season].

The spatial distribution characteristics of the mass concentration of V, Cr, Mn, Ni, Cu, Zn, Pb, Cd, Fe, and Sb in the Chaohu Lake basin and ten surrounding rivers during the wet season were explored. The results showed that the average mass concentration of heavy metals in the western and northwestern Chaohu Lake surrounding rivers was higher than that in the central and eastern regions. The correlation analysis showed a significant positive correlation between the concentrations of Cu, Ni, Zn, Pb, and Cd, which indicated a similarity of spatial distribution among the five elements. The single-factor pollution index evaluation results classified Cr in the ten surrounding rivers as Grade I based on the Environmental Quality Standards for Surface Water. Pb was classified as Grade Ⅰ-Ⅱ; Cu and Zn as Grade Ⅰ-Ⅴ; Fe, Sb, and V were far below the standard limit; Ni slightly exceeded the standard at some sampling points of the Nanfei River; Mn slightly exceeded the standard at some points of the Shiwuli and Pai River; Cd exceeded the standard at some points of the Nanfei River. Except Mn at one point of the Tangxi River, V, Cr, Ni, Cu, Zn, Pb, and Fe were all<1, which indicated clean and pollution-free level. The integrated pollution index of the rivers surrounding the lake in the northwestern part was the highest compared to the southwestern, central, and eastern parts.

Fecal steroids in riverine runoff of the Pearl River Delta, South China: levels, potential sources and inputs to the coastal ocean.

Domestic sewage is a potential source of contamination deteriorating water quality in rivers and coastal environments. The present study determined the concentrations of eight steroids in both filtrate and suspended particulate matter (SPM) samples collected monthly at the eight major riverine runoff outlets of the Pearl River Delta (PRD), South China, from March 2005 to February 2006. The concentration of the eight steroids (sum of which is defined as Sigma(8)steroid) in the filtrate and SPM samples ranged 16.7-1340 ng L(-1) and 0.44-240 microg g(-1), respectively. The filtrate samples contained the highest levels of cholesterol (CHOE) and stigmasterol (STIG) on average, whereas the SPM samples had the largest relative abundances of CHOE and coprostanol (COP). In general, larger proportions of the steroids were associated with SPM than with the filtrate phase. The combined (filtrate plus SPM) concentrations of COP in riverine runoff of the PRD were at the midpoint of the global range in surface water. The concentrations of Sigma(8)steroid and COP in SPM were not significantly correlated with particulate organic carbon (POC), riverine runoff, or SPM concentrations, which indicates the dominance of nonpoint input sources for the occurrence of steroids in the PRD. The annual riverine inputs of Sigma(8)steroid and COP were estimated at 360 and 31.6 tons yr(-1), respectively, and the monthly inputs of both Sigma(8)steroid and COP were positively correlated with monthly runoff discharge. Furthermore, the concentrations of Sigma(8)steroid, COP, and CHOE showed significant temporal and spatial variability. These results can be explained by a combination of climatic characteristics, socioeconomic conditions, and steroid sources. Analyses of the diagnostic indices of COP and background information suggested that riverine runoff from the PRD may have been affected by domestic wastewater, which appeared to be a major COP source to the Pearl River Estuary and South China Sea.

Some potential hazardous trace elements contamination and their ecological risk in sediments of western Chaohu Lake, China.

The Chaohu is one of the largest five freshwater lakes in China. It provides freshwater for agriculture, life, and part of industry. The quality of water becomes worst and worst due to the toxic matter. In this study, we collected the samples from the sedimentary mud in the lake. The distribution of some potential hazardous trace elements (Cu, Ni, Cr, As, Pb, Cd, and Hg) in the sediments of western Chaohu Lake, has been determined and studied, and the enrichment factors, the index of geoaccumulation, and potential ecological risk were analyzed and calculated. The results show that: the levels of selected potential hazardous trace element vary from different sampling sites and significant anthropogenic impact of Pb and Cd occur in sediments. The contamination rank of Pb and Cd are moderate, and Pb has a light potential ecological risk, but Cd is heavy. The total potential ecological risk of the selected hazardous trace elements in this study in Chaohu Lake is moderate. Cluster and correlation analysis indicate that the selected potential hazardous trace element pollutant has different source and co-contamination also occur in sediments.

Serum proteomes of hypertension patients with abundant phlegm-dampness.

OBJECTIVE: To study the serum proteomes of essential hypertension (EH) patients with abundant phlegm-dampness, and try to find special proteins associated with abundant phlegm-dampness syndrome. METHODS: Fifty-nine hypertension patients were included, and the patients were divided into abundant phlegm-dampness syndrome group (39 cases) and non-phlegm-dampness syndrome group (20 cases). To find the special proteins associated with abundant phlegm-dampness, the EH patients with non-phlegm-dampness and another 30 healthy persons were regarded as control. Weak cation nano-magnetic beads were used to capture proteins in serum, and proteomic fingerprint was made by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). All the proteomic fingerprints were analyzed by Biomarker Wizard 3.1 Software. Then Biomarker Patterns Software (BPS) 5.0 was used to identify the differentiated proteins, which could induce phlegm-dampness. RESULTS: There were 102 differentiated protein peaks between abundant phlegm-dampness and the control group. The best markers of abundant phlegm-dampness were protein peaks with the mass to charge ratio (m/z) of 9,334.958 m/z (the expression increased), 9,280.191 m/z (the expression decreased), 8,030.794 m/z (the expression increased), and 2,941.551 m/z (the expression increased). These four protein peaks found by BPS could induce abundant phlegm-dampness. They could be used to separate the abundant phlegm-dampness syndrome from the healthy persons and the hypertension patients with non-phlegm-dampness. The sensitivity of the model was 93.103% (27/29), specificity was 92% (23/25), false positive rate was 8% (2/25), false negative rate was 6.897% (2/29) and Youden's index was 85.103%. Blind test data indicated a sensitivity of 90% (9/10) and a specificity of 88% (22/25), and the false positive rate was 12% (3/25), false negative rate was 10% (1/10), and Youden's index was 78%. CONCLUSION: The differentiated proteins between the abundant phlegm-dampness group and the control group are the material foundation of abundant phlegm-dampness. The selected differentiated proteins can be used to distinguish the EH patients with abundant phlegm-dampness from the healthy persons and the EH patients with non-phlegm-dampness. The molecular biology diagnosis model can offer an objective and accurate way for TCM syndrome differentiation.

[Elemental Composition Characteristics of PM2.5 and PM10, and Heavy Pollution Analysis in Hefei].

Through the collection of atmospheric PM2.5 and PM10 samples in Hefei in 2018, combined with high-precision testing of elements in these samples, the elemental composition of PM2.5 and PM10 was studied during heavy pollution episodes and under non-pollution conditions. The main pollutant sources and causes of heavy pollution in Hefei are also discussed based on an analysis of the differences in the element composition of atmospheric particles. The results showed that, among the 16 elements detected, the mass concentrations of Si, Al, Mg, and Ca during heavy pollution episodes were lower than during non-polluted conditions. This may have been caused by a reduction in ground dust emission caused by calmer winds during heavily polluted conditions. In comparison, the mass concentrations of S, Na, K, Cl, Ti, Fe, P, Cu, and Ni were higher during heavy pollution episodes than during non-pollution conditions, and the difference was greatest for S. The proportion and enrichment factors for S were also greatly increased during heavy pollution events, indicating that its emission from coal burning is the main source of pollution in Hefei. The heavy metal content was low, however, and the enrichment factor was high, the main sources of which may be garbage incineration, motor vehicles, and industrial emissions.

Effects of cesium accumulation on chlorophyll content and fluorescence of Brassica juncea L.

The aim of our study was to investigate the toxicological mechanism of cesium on Indian mustard (Brassica juncea L.). The impact of cesium toxicity to plants was evaluated using phytophysiology and genetic methods. In this study, Brassica juncea was grown on Cs-contaminated Hoagland's nutrient solution, and chlorophyll content, chlorophyll fluorescence, and Cs bioaccumulation were measured. Transcriptome data was used to perform an in-depth analysis of the molecular mechanisms underlying the effects of Cs accumulation. The results showed that Cs accumulated up to 3586.70 mg kg-1 in B. juncea treated with 100 mg L-1 Cs. The chlorophyll content and several chlorophyll fluorescence parameters (Fv/F0, Fv/Fm, ΦPS II, qP, and NPQ) significantly decreased under Cs exposure. The starting process of PSII was also inhibited under higher Cs conditions. These results indicate that excessive Cs can damage PS II in leaves, decreasing photochemical activity and the energy conversion rate. Further analysis revealed that Cs interfered with the expression of chloroplastic metabolic genes (25 up and 36 down) and inhibited the expression of PsaB, psbC, PetF, LHCA1, and LHCB5. The results indicate that stable Cs leads to abnormal expression of genes related to photosynthesis pathway, blocking the electron transport process from plastoquinone-QA to plastoquinone-QB, resulting in abnormal photosynthesis, which leads to abnormal growth of B. juncea.

[Temporal-spatial Distribution and Pollution Assessment of Dissolved Heavy Metals in Chaohu Lake].

Surface water samples were collected in different seasons from Chaohu Lake to determine the concentrations and potential environmental impacts of nine dissolved heavy metals (As, Hg, Cd, Cu, Pb, Zn, Cr, Ni, and Co). The concentrations of the selected heavy metals were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES, ICAP6000 series). The single pollution index method and integrated pollution index method were used to evaluate the potential environmental impacts. The results indicated that the contents of dissolved As, Cd, Pb, and Cr in Chaohu Lake were lower than the limitations of GradeⅠof the Environmental Quality Standards for Surface Water (GB 3838-2002), while Cu and Zn were within the limitations of GradeⅠ-Ⅱ and Hg was within the limitations of GradeⅠ-Ⅲ. The contents of Ni and Co were far below the limitations. The concentrations of the selected heavy metals (Cu, Pb, Zn, Cr, Ni, and Co) varied among seasons and areas. Elevated concentrations of Cu, Zn, and Ni were found in summer, while elevated contents of Pb, Cr, and Co were found in autumn, autumn, and spring, respectively. Trace elements in the western part of Chaohu Lake (especially in the northwestern part) were higher than those in the middle and eastern parts for autumn, winter, and summer. Significant positive correlations were found among Cu, Pb, Zn, Cr, and Ni in the surface water, suggesting that these elements may derive from similar sources. The values of both the single factor pollution index and integrated pollution index of the selected elements in the surface water were far less than 1, suggesting that the environmental impacts could be regarded as negligible. The integrated pollution indices in the western part of the lake were higher than those of the middle and eastern parts on a one-year timescale, and the integrated pollution indices in each lake area followed a pattern of wet season (summer) > normal season (spring and autumn) > dry season (winter).

[Spatial and Temporal Distributions of Nitrogen and Phosphate in the Chaohu Lake].

In order to determine the concentrations, spatial and temporal distributions of nitrogen ( N) and phosphorus (P) nutrients in Chaohu Lake, the surface water samples were collected systemically in different flood seasons by grid sampling methods. Meanwhile, the predominant pollution factors and priority control area were confirmed. The results showed that the concentrations of TP, TN and NO3- -N in the inflowing rivers were higher than the V class water standard, the concentrations of nutrients in wet season were lower than those in normal season and dry season in Nanfei River and Shiwuli River, while the levels of nutrients in the other selected rivers were higher in wet season. The variations of spatial and temporal of nutrients were observed in the Chaohu Lake. The concentrations of N and P nutrients in the western part of Chaohu Lake were higher than those of the eastern part. The elevated concentrations of TP, TN and NH4+ -N were found in the dry season, while the elevated content of NO3- -N was observed in the wet season. The predominant pollution factors in Chaohu Lake were TN and NH4+ -N, the concentrations of these nutrients were decreasing from the western part of the Chaohu Lake to the eastern part of the Chaohu Lake.

Elevated glycated hemoglobin levels may increase the risk of atrial fibrillation in patients with diabetes mellitus.

BACKGROUND: As the most common cardiac arrhythmia, atrial fibrillation (AF) is always accompanied with various complications if without detection and treatment timely. Blood-based pleiotropic molecule biomarkers have now been popularly applied in clinical detection. We hence performed this meta-analysis to evaluate the correlation of serum glycated hemoglobin (HbA1c) levels with the risk of AF in patients with diabetes mellitus (DM). METHODS: Covering myriads of computerized databases, we identified potential relevant studies for statistical analysis. We used a standard reporting form to extract data from each included study. Newcastle-Ottawa Scale (NOS) criteria was used for methodological quality assessment. Statistical analyses were conducted with the STATA statistical software. RESULTS: Six cohort studies in full text fulfilled our inclusion criteria, and following overestimation indicated that serum levels of HbA1c in DM patients with AF was higher than that in DM patients without AF (SMD = 0.67, 95% CI: 0.39-0.94, P < 0.001). Subgroup analyses by sample size and detection method implicated that elevated serum HbA1c levels exhibited significant correlations with an increased risk of AF in DM patients in the large-size subgroup (n ≥ 200), the small-size subgroup (n < 200), the high performance liquid chromatography (HPLC) subgroup and the non-HPLC subgroup (Large-size: SMD = 0.70, 95% CI: 0.38-1.03, P < 0.001; Small-size: SMD = 0.64, 95% CI: 0.09-1.19, P = 0.023; HPLC: SMD = 0.81, 95% CI: 0.49-1.12, P < 0.001; Non-HPLC: SMD = 0.36, 95% CI: 0.04-0.68, P = 0.029; respectively). CONCLUSION: Elevated serum HbA1c levels may be associated with an increased risk of AF in DM patients, possibly reflecting that serum HbA1c level might be a potential biomarker in the prediction of AF in DM patients.

[Analysis of antimicrobial resistance of clinical isolates of enterococci from Beijing and other areas in China].

OBJECTIVE: To analyze the antimicrobial resistance of enterococci in Beijing and other areas in China. METHODS: Disk diffusion method was used to test the antimicrobial resistance of 1978 enterococcal isolates from 4 teaching hospitals in Beijing and 53 grade 3 A hospitals in other areas of China The laboratory data were analyzed by WHONET5 statistic software. RESULTS: Enterococcus. faecalis isolates and E. facium isolates accounted for 80.7% and 17.1% of the enterococcus isolates in Beijing and 79.4% and 15.2% in other areas respectively. The enterococcus isolates from urine, sputum, secretion with pus, blood, and bile accounted for 33.7%, 22.9%, 9.8%, 4.4%, and 3.0% of the enterococcus isolates in Beijing and 28.4%, 16.3%, 14.6%, 5.0%, and 4.5% in other areas respectively. The resistance rates of E. faecalis to vancomycin, teicoplanin, ampicillin, and high -level gentamicin were 2.0%, 1.4%, 17.7%, and 47.4% in Beijing, and 5.1%, 3.7%, 24%, and 49.2% in other areas; The resistance rates of E. faecium to vancomycin, teicoplanin, ampicillin, and high -level gentamicin were 1.5%, 2.6%, 64.2%, and 64.9% in Beijing, and 2.1%, 3.1%, 68.5%, and 62.3% in other areas respectively. The vancomycin-resistant rate of the total isolates of enterococci was 3.2%. CONCLUSION: Enterococcus faecalis is the main species in the enterococcus isolates from clinical samples. E. facium, as compared with E. faecalis resists many antimicrobial agents more strongly. Both of E. faecalis and E. facium show the least resistance to vancomycin and teicoplanin.

A single nucleotide polymorphism in PIK3CA gene is inversely associated with P53 protein expression in breast cancer.

Single nucleotide polymorphism (SNP) rs17849071 was recently reported to be inversely associated with PIK3CA amplification in follicular thyroid cancer, but the main function of this SNP remains unclear. In this study, by using PCR and sequencing method, we explored whether this SNP was associated with P53 expression status and other clinicopathological characteristics in 62 Chinese breast cancer (BCa) patients. In our results, P53 protein accumulation was significantly associated with HER2 overexpression (P = 0.013) and Ki-67 expression (P = 0.007), which were in accord with previous studies. Besides, there was a significantly inverse relationship between P53 protein expression and rs17849071 GT+GG genotype in Chinese BCa patients (P = 0.044). The SNP was not related to other important BCa markers such as estrogen receptor, progestin receptor, and HER2. Among different BCa intrinsic subtypes, no significant differences were found on P53 expression status (P = 0.356) or rs17849071 polymorphism (T>G) (P = 0.813). In conclusion, SNP rs17849071 GT+GG genotype was inversely associated with P53 protein accumulation in BCa samples. Studies with larger sample size focusing on exploring the relationship of rs17849071 polymorphisms, P53 accumulation, P53 mutations, and PIK3CA amplification might be needed.

Prognostic role of PIK3CA mutations and their association with hormone receptor expression in breast cancer: a meta-analysis.

The phosphatidylinositol-4, 5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) gene is frequently mutated in breast cancer (BCa). Sex hormone receptors (HRs), including estrogen receptor (ER) and progesterone receptor (PR) play pivotal roles in BCa. In this study, we evaluated the association between PIK3CA mutations and ER/PR expression and the prognostic role of PIK3CA mutations in BCa patients, and in particular, HR-positive BCa. Thirty-two studies involving 5719 cases of BCa obtained from database searches were examined. PIK3CA gene mutations correlated significantly with ER/PR expression (p < 0.00001) and relapse-free survival (RFS) (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.59-0.98, p = 0.03) but not overall survival (OS) (HR 1.14, 95%CI 0.72-1.82, p = 0.57) in unsorted BCa patients. PIK3CA mutations were not associated with OS (HR 1.06, 95%CI 0.67-1.67, p = 0.81) or RFS (HR 0.86, 95%CI 0.53-1.40, p = 0.55) in HR-positive BCa patients. In conclusion, PIK3CA mutations were significantly related to ER/PR expression and RFS in unsorted BCa patients. However, the clinical implications of PIK3CA mutations may vary according to different mutant exons. And PIK3CA mutations alone may have limited prognostic value for HR-positive BCa patients.

Synthesis and antitumor activity of a series of osmium(VI) nitrido complexes bearing quinolinolato ligands.

A series of osmium(VI) nitrido complexes supported by quinolinolato ligands have been prepared and they exhibit promising in vitro anti-cancer activities. These results establish that Os(VI)≡N is a potentially versatile and promising platform for the design of a variety of high-valent anti-cancer drugs.

Development of a high sensitivity, nested Q-PCR assay for mouse and human aromatase.

Measurement of breast tissue estradiol levels could provide a powerful method to predict the risk of developing breast cancer but obtaining sufficient amounts of tissue from women is difficult from a practical standpoint. Assessment of aromatase in ductal lavage fluid or fine needle aspirates from breast might provide a surrogate marker for tissue estrogen levels but highly sensitive methods would be required. These considerations prompted us to develop an ultra-sensitive, "nested" PCR assay for aromatase which is up to one million fold more sensitive than standard PCR methods. We initially validated this assay using multiple tissues from the aromatase transgenic mouse and found that coefficients of variation for measurement of replicate samples averaged less than 5%. We demonstrated a 60-fold enhancement in aromatase message in the transgenic versus the wild type mouse breast but surprisingly, levels in the transgenic animals were highly variable, ranging from 0.4 to 27 relative units. The variability of aromatase expression in the transgenic breast did not correlate with the degree of breast development and did not appear to relate to hormonal manipulation of the MMTV promoter but probably related to lack of exhaustive inbreeding and mixed zygocity of transgenic animals. Extensive validation in mouse tissues provided confidence regarding the assay in human tissues, since nearly identical methods were used. The human assay was sufficiently sensitive to detect aromatase in a single human JAR (choriocarcinoma) cell, in all breast biopsies measured, and in 7/23 ductal lavage fluids.