Topical treatments for scalp psoriasis: summary of a Cochrane Systematic Review.

People with chronic plaque psoriasis often have lesions on the scalp that are difficult to treat. This report is a summary of a Cochrane review on the efficacy and safety of topical treatments for scalp psoriasis. For quality-of-evidence assessment, we used the Grading of Recommendations Assessment, Development and Evaluation Working Group approach. Only randomized controlled trials (RCTs) were eligible for inclusion. We searched the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase and LILACS; ongoing trials; indexes of included studies and screened abstracts of six psoriasis-specific conferences up to August 2015. We included 59 RCTs, with 11 561 participants overall. Most findings were limited to short-term treatments (< 6 months). According to the clinician and patients' self-assessment, a corticosteroid-vitamin D combination (e.g. betamethasone dipropionate plus calcipotriol) and corticosteroids of high and very high potency were better than vitamin D. The two-compound combination was superior to the corticosteroid alone, but the additional benefit was small. Reporting of quality-of-life data was insufficient. The two-compound combination and corticosteroids caused fewer withdrawals due to adverse events than vitamin D. There was no difference between the two-compound combination and corticosteroid monotherapy concerning this outcome. Overall the evidence was of moderate quality. Evaluation of other topical treatments was limited. Given the comparable safety profile and only slim benefit of the two-compound combination over the corticosteroid alone, monotherapy with generic topical corticosteroids of high and very high potency may be fully acceptable for short-term therapy. More quality-of-life data and long-term assessments are needed.

Report from the kick-off meeting of the Cochrane Skin Group Core Outcome Set Initiative (CSG-COUSIN).

A major obstacle of evidence-based clinical decision making is the use of nonstandardized, partly untested outcome measurement instruments. Core Outcome Sets (COSs) are currently developed in different medical fields to standardize and improve the selection of outcomes and outcome measurement instruments in clinical trials, in order to pool results of trials or to allow indirect comparison between interventions. A COS is an agreed minimum set of outcomes that should be measured and reported in all clinical trials of a specific disease or trial population. The international, multidisciplinary Cochrane Skin Group Core Outcome Set Initiative (CSG-COUSIN) aims to develop and implement COSs in dermatology, thus making trial evidence comparable and, herewith, more useful for clinical decision making. The inaugural meeting of CSG-COUSIN was held on 17-18 March 2015 in Dresden, Germany, as the exclusive theme of the Annual Cochrane Skin Group Meeting. In total, 29 individuals representing a broad mix of different stakeholder groups, professions, skills and perspectives attended. This report provides a description of existing COS initiatives in dermatology, highlights current methodological challenges in COS development, and presents the concept, aims and structure of CSG-COUSIN.

A near-field scanning microwave microscope for characterization of inhomogeneous photovoltaics.

We present a near-field scanning microwave microscope (NSMM) that has been configured for imaging photovoltaic samples. Our system incorporates a Pt-Ir tip inserted into an open-ended coaxial cable to form a weakly coupled resonator, allowing the microwave reflection S(11) signal to be measured across a sample over a frequency range of 1 GHz - 5 GHz. A phase-tuning circuit increased impedance-measurement sensitivity by allowing for tuning of the S(11) minimum down to -78 dBm. A bias-T and preamplifier enabled simultaneous, non-contact measurement of the DC tip-sample current, and a tuning fork feedback system provided simultaneous topographic data. Light-free tuning fork feedback provided characterization of photovoltaic samples both in the dark and under illumination at 405 nm. NSMM measurements were obtained on an inhomogeneous, third-generation Cu(In,Ga)Se(2) (CIGS) sample. The S(11) and DC current features were found to spatially broaden around grain boundaries with the sample under illumination. The broadening is attributed to optically generated charge that becomes trapped and changes the local depletion of the grain boundaries, thereby modifying the local capacitance. Imaging provided by the NSMM offers a new RF methodology to resolve and characterize nanoscale electrical features in photovoltaic materials and devices.

Photoluminescence polarization in strained GaN/AlGaN core/shell nanowires.

The optical polarization properties of GaN/AlGaN core/shell nanowire (NW) heterostructures have been investigated using polarization resolved micro-photoluminescence (µ-PL) and interpreted in terms of a strain-dependent 6 × 6 k·p theoretical model. The NW heterostructures were fabricated in two steps: the Si-doped n-type c-axis GaN NW cores were grown by molecular beam epitaxy (MBE) and then epitaxially overgrown using halide vapor phase epitaxy (HVPE) to form Mg-doped AlGaN shells. The emission of the uncoated strain-free GaN NW core is found to be polarized perpendicular to the c-axis, while the GaN core compressively strained by the AlGaN shell exhibits a polarization parallel to the NW c-axis. The luminescence of the AlGaN shell is weakly polarized perpendicular to the c-axis due to the tensile axial strain in the shell.

Expression of genes related to oxidative stress in the mouse brain after exposure to silver-25 nanoparticles.

Nanoparticles are small scale substances (<100 nm) used in biomedical applications, electronics, and energy production. Increased exposure to nanoparticles being produced in large-scale industry facilities elicits concerns for the toxicity of certain classes of nanoparticles. This study evaluated the effects of silver-25 nm (Ag-25) nanoparticles on gene expression in different regions of the mouse brain. Adult-male C57BL/6N mice were administered (i.p.) 100mg/kg, 500 mg/kg or 1,000 mg/kg Ag-25 and sacrificed after 24h. Regions from the brain were rapidly removed and dissected into caudate nucleus, frontal cortex and hippocampus. Total RNA was isolated from each of the three brain regions collected and real-time RT-PCR analysis was performed using Mouse Oxidative Stress and Antioxidant Defense Arrays. Array data revealed the expression of genes varied in the caudate nucleus, frontal cortex and hippocampus of mice when treated with Ag-25. The data suggest that Ag-25 nanoparticles may produce neurotoxicity by generating free radical-induced oxidative stress and by altering gene expression, producing apoptosis and neurotoxicity.

Unique cellular interaction of silver nanoparticles: size-dependent generation of reactive oxygen species.

The rapid advancement of nanotechnology has created a vast array of engineered nanomaterials (ENMs) which have unique physical (size, shape, crystallinity, surface charge) and chemical (surface coating, elemental composition and solubility) attributes. These physicochemical properties of ENMs can produce chemical conditions to induce a pro-oxidant environment in the cells, causing an imbalanced cellular energy system dependent on redox potential and thereby leading to adverse biological consequences, ranging from the initiation of inflammatory pathways through to cell death. The present study was designed to evaluate size-dependent cellular interactions of known biologically active silver nanoparticles (NPs, Ag-15 nm, Ag-30 nm, and Ag-55 nm). Alveolar macrophages provide the first defense and were studied for their potential role in initiating oxidative stress. Cell exposure produced morphologically abnormal sizes and adherence characteristics with significant NP uptake at high doses after 24 h. Toxicity evaluations using mitochondrial and cell membrane viability along with reactive oxygen species (ROS) were performed. After 24 h of exposure, viability metrics significantly decreased with increasing dose (10-75 microg/mL) of Ag-15 nm and Ag-30 nm NPs. A more than 10-fold increase of ROS levels in cells exposed to 50 microg/mL Ag-15 nm suggests that the cytotoxicity of Ag-15 nm is likely to be mediated through oxidative stress. In addition, activation of the release of traditional inflammatory mediators were examined by measuring levels of cytokines/chemokines, including tumor necrosis factor (TNF-alpha), macrophage inhibitory protein (MIP-2), and interleukin-6 (IL-6), released into the culture media. After 24 h of exposure to Ag-15 nm nanoparticles, a significant inflammatory response was observed by the release of TNF-alpha, MIP-2, and IL-1beta. However, there was no detectable level of IL-6 upon exposure to silver nanoparticles. In summary, a size-dependent toxicity was produced by silver nanoparticles, and one predominant mechanism of toxicity was found to be largely mediated through oxidative stress.

A passively mode-locked fiber laser at 1.54 mum with a fundamental repetition frequency reaching 2 GHz.

We demonstrate a fundamentally mode-locked fiber laser with a repetition frequency in excess of 2 GHz at a central wavelength of 1.535 mum. Co-doped ytterbium-erbium fiber provides the gain medium for the laser, affording high gain per unit length, while a semiconductor saturable absorber mirror (SAM) provides the pulse shaping mechanism in a standing wave cavity. Results are shown confirming cw mode-locking for 1 GHz and 2 GHz repetition frequency systems. The response of the frequency comb output to pump power variations is shown to follow a single pole response. The timing jitter of a 540MHz repetition-rate laser has been suppressed to below 100 fs through phase-lead compensated feedback to the pump power. Alternatively, a single comb line of a 850MHz repetition-rate laser has been phase-locked to a narrow linewidth cw laser with an in-loop phase jitter of 0.06 rad(2). The laser design is compatible with low-noise oscillator applications.

In vitro toxicity of nanoparticles in BRL 3A rat liver cells.

This study was undertaken to address the current deficient knowledge of cellular response to nanosized particle exposure. The study evaluated the acute toxic effects of metal/metal oxide nanoparticles proposed for future use in industrial production methods using the in vitro rat liver derived cell line (BRL 3A). Different sizes of nanoparticles such as silver (Ag; 15, 100 nm), molybdenum (MoO(3); 30, 150 nm), aluminum (Al; 30, 103 nm), iron oxide (Fe(3)O(4); 30, 47 nm), and titanium dioxide (TiO(2); 40 nm) were evaluated for their potential toxicity. We also assessed the toxicity of relatively larger particles of cadmium oxide (CdO; 1 microm), manganese oxide (MnO(2); 1-2 microm), and tungsten (W; 27 microm), to compare the cellular toxic responses with respect to the different sizes of nanoparticles with different core chemical compositions. For toxicity evaluations, cellular morphology, mitochondrial function (MTT assay), membrane leakage of lactate dehydrogenase (LDH assay), reduced glutathione (GSH) levels, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were assessed under control and exposed conditions (24h of exposure). Results showed that mitochondrial function decreased significantly in cells exposed to Ag nanoparticles at 5-50 microg/ml. However, Fe(3)O(4), Al, MoO(3) and TiO(2) had no measurable effect at lower doses (10-50 microg/ml), while there was a significant effect at higher levels (100-250 microg/ml). LDH leakage significantly increased in cells exposed to Ag nanoparticles (10-50 microg/ml), while the other nanoparticles tested displayed LDH leakage only at higher doses (100-250 microg/ml). In summary the Ag was highly toxic whereas, MoO(3) moderately toxic and Fe(3)O(4), Al, MnO(2) and W displayed less or no toxicity at the doses tested. The microscopic studies demonstrated that nanoparticle-exposed cells at higher doses became abnormal in size, displaying cellular shrinkage, and an acquisition of an irregular shape. Due to toxicity of silver, further study conducted with reference to its oxidative stress. The results exhibited significant depletion of GSH level, reduced mitochondrial membrane potential and increase in ROS levels, which suggested that cytotoxicity of Ag (15, 100 nm) in liver cells is likely to be mediated through oxidative stress.

Army medical laboratory telemedicine: role of mass spectrometry in telediagnosis for chemical and biological defense.

An army medical field laboratory presently has the capability of performing standard protocols developed at the US Army Medical Research Institute of Chemical Defense for verification of nerve agent or sulfur mustard exposure. The protocols analyze hydrolysis products of chemical warfare agents using gas chromatography/mass spectrometry. Additionally, chemical warfare agents can produce alkylated or phosphorylated proteins following human exposure that have long biological half-lives and can be used as diagnostic biomarkers of chemical agent exposure. An analytical technique known as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) currently is being examined for its potential to analyze these biomarkers. The technique is capable of detecting large biomolecules and modifications made to them. Its fast analysis time makes MALDI-TOF/MS technology suitable for screening casualties from chemical or biological attacks. Basic operation requires minimal training and the instrument has the potential to become field-portable. The limitation of the technique is that the generated data may require considerable expertise from knowledgeable personnel for consultation to ensure correct interpretation. The interaction between research scientists and field personnel in the acquisition of data and its interpretation via advanced digital telecommunication technologies can enhance rapid diagnosis and subsequently improve patient care in remote areas.

Stress gene activity in HepG2 cells after sulfur mustard exposure.

Monitoring temporal stress gene (SG) levels is one method of characterizing cellular responses to toxic-level chemical exposures. The goal of this study was to determine human cellular SG profiles following sulfur mustard (SM) exposure. This would establish a baseline for development of a rapid screening method for potential therapeutic compounds that could modulate SM toxicity. We used a panel of cells consisting of 14 HepG2-derived cell lines each stably transformed with a stress gene promoter (SGP) or stress gene response element (SGRE) controlling the transcription of the reporter gene chloramphenicol acetyltransferase (CAT). The SGP and SGRE reporter constructs represent SGs associated with DNA damage, protein damage, oxidative stress, inflammation, second messenger systems and xenobiotic metabolism enzymes. All SGP and SGRE activities were changed from control following SM exposure over dose and the 24-h time-course study. Metallothionein 2A promoter (MT2A) was induced throughout the study time at high SM concentration. DNA-damage markers were induced after 12 h. Protein damage, inflammation and second messenger systems increased after 16 h post-SM exposure. These results show that over time and increasing SM exposure concentrations the HepG2 cells produced differential activation of SGPs and SGREs associated with DNA and protein damage, second messenger system activation and inflammation/oxidative stress. This suggests that the HepG2 cell reporter construct system would be a useful tool for studying the effects of known therapeutic drug families that may lower these cell-damage markers during SM exposure.

MALDI-ToF/MS as a diagnostic tool for the confirmation of sulfur mustard exposure.

The continual threat of chemical and biological warfare has prompted the need for unambiguous analytical methods for the confirmation of agent exposure. In this paper, we have investigated the use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF/MS) as a diagnostic tool for this purpose. Mass spectral studies of the interaction of sulfur mustard (bis-(2-chloroethyl) sulfide, HD) with hemoglobin and metallothioneine were conducted. In vitro experiments with purified proteins were performed, using both HD and chloroethylethyl sulfide (CEES), in an effort to determine the extent of alkylation and occurrence of HD cross-linking using the MALDI-ToF/MS technique. In a typical experiment, 50 ml of 5 mM HD in acetonitrile was added to an equal volume of 0.5 mM hemoglobin in deionized water followed by vortexing and incubation at room temperature. After 24 h, the samples were analyzed by MALDI-ToF/MS. Mass spectral results indicated the presence of at least two distinct alkylation adducts for both HD and CEES experiments. These results demonstrate that MALDI-ToF/MS is a useful analytical technique to investigate the interaction of HD with biomolecules and may be employed potentially as a diagnostic tool for the confirmation of exposure to chemical warfare agents.

Expression and partial purification of a recombinant secretory form of human liver carboxylesterase.

Serine-dependent carboxylesterases (EC 3.1.1.1) are found in a variety of tissues with high activity detected in the liver. Carboxylesterases (CaE) hydrolyze aliphatic and aromatic esters, and aromatic amides, and play an important role in the detoxification of xenobiotic chemicals that contain organophosphate (OP) compounds. The detoxifying ability of CaE is limited by its low concentration in serum where it encounters OP compounds. Studies in our laboratory have shown that a pRC/CMV-hCaE plasmid construct, stably integrated into 293T cells, expresses a human liver CaE in culture. However, the enzyme remained inside the cell and reached a low steady-state level of expression. The goals of this study were to overexpress a functional human liver CaE from a recombinant cDNA in a human cell line and to isolate and purify the recombinant protein. To accomplish these goals, a single amino acid change was made in the C-terminal retrieval signal, HIEL (His-Ile-Glu-Leu), of human liver CaE. The mutation produced a unique Eco47III restriction site, which aided in clone selection. The recombinant plasmid, pRc/CMV-mhCaE, was isolated and stably integrated into human 293T cells. Expression of the altered cDNA resulted in secretion of an active CaE up to levels of 500 enzyme units per liter of growth medium. Secretory CaE displayed isoelectric focusing patterns similar to those of the native enzyme with no observable changes in activity. The secreted enzyme was partially purified by hydrophobic interaction chromatography and Cibacron blue affinity chromatography. Partial enzyme purification was achieved, and CaE retained a high level of enzymatic activity.

Accurate Measurements of the Zero-Dispersion Wavelength in Optical Fibers.

We have developed a frequency-domain phase shift system for measuring the zero-dispersion wavelength and the dispersion slope of single-mode optical fibers. A differential phase shift method and nonlinear four-wave mixing technique were also investigated. The frequency-domain phase shift method is used to produce Standard Reference Materials that have their zero-dispersion wavelengths characterized with an expanded uncertainty (k = 2) of ± 0.060 nm.

A phage display vector with improved stability, applicability and ease of manipulation.

We modified a combinatorial library display vector, pCOMB3, to provide a stable, easily manipulated, high-copy vector for the display of a random hexapeptide library. The propensity of the original phagemid to accumulate 800-1000-bp deletions in the region of the cloning site has been eliminated. Furthermore, the small 63-bp 'stuffer' at the cloning site was replaced with a 2114-bp DNA fragment from adenovirus 2. This produced a 5808-bp vector, that we have named pICD1LS, with the appropriate characteristics for single-peptide phage display. Libraries of greater than 10(6) molecules were produced with this vector.

Capillary gel electrophoresis as a method to determine ligation efficiency.

A capillary gel electrophoresis (CGE) method is described for detection of the formation of circular DNA ligation products as an aid in the prediction of ligated DNA competent cell transformation efficiency. The separation is based upon the differences in the relative migrations of linear and circular DNA molecules of the same size. In CGE, circular ligation products are shifted significantly from linear DNA fragments of comparable size (to 40-42 min from 32-33 min migration time) in the presence of an intercalating dye. CGE separation and detection of circularized DNA can be correlated with transformation efficiencies of > 10(6) colony-forming units (CFU, colonies/micrograms/ml) or the high efficiency desired for phagemid display and cell expression libraries. CGE has several advantages over slab gel electrophoresis: (i) only a minute quantity (approximately 250 CFU or 0.02%) of the total library is sacrificed for analysis, (ii) verification of the circularized ligation products is easier by CGE, and (iii) CGE analysis of ligation success can be accomplished in less than 2 h, prior to transforming competent cells.

Increased NAD(P)H:(quinone-acceptor)oxidoreductase activity is associated with density-dependent growth inhibition of normal but not transformed cells.

The activity of DT-diaphorase [NAD(P)H:(quinone-acceptor)oxidoreductase] is increased 7-fold in wild-type BALB/c 3T3T cells as they reach confluence and become density growth arrested. Harvesting and replating the cells at low density resulted in a loss of DT-diaphorase with a half time of 7 h, and removal of serum from high-density growth-arrested cells resulted in a decrease in DT-diaphorase with a half time of 3 days. Platelet-derived growth factor and insulin together, but not singly, maintain elevated DT-diaphorase levels in high-density growth-arrested BALB/c 3T3T cells. The increase in DT-diaphorase at high density diminished proportionately to the extent of transformation in four cell lines, 4NQO-3T3T, UV-3T3T, EJras-3T3T. and CSV3-1-3T3T. The most transformed cell line, CSV3-1-3T3T, showed no increase in DT-diaphorase at high density. Since there was no increase in DT-diaphorase mRNA in high-density growth-arrested wild-type BALB/c 3T3T cells compared to rapidly growing cells, the increase in DT-diaphorase activity at high density is most likely due to posttranslational events. High-density growth-arrested wild-type BALB/c 3T3 cells exhibited a greater sensitivity to growth inhibition by the antitumor quinone diaziquone [1,4-cyclohexadiene-1,4- dicarbamic acid, 2,5-bis(1-aziridinyl)-3,6-dioxo-, diethyl ether], which is metabolically activated by DT-diaphorase, than do low-cell-density, growth-arrested cells. The significance of the increase in DT-diaphorase at high cell density in normal cells and its loss in transformed cells may be related to the phenomenon of density-dependent growth inhibition in nontransformed but not in transformed cells.

Condensed tannin promotes the release of arachidonic acid from rabbit resident alveolar macrophages.

The condensed tannin present in cotton mill dust profoundly alters the functional capabilities of resident alveolar macrophages. Previous studies from this laboratory have shown that in vitro exposure of rabbit resident alveolar macrophages to condensed tannin significantly inhibits the ability of these cells to produce reactive oxygen intermediates or to ingest particles. In the present study, we demonstrate that condensed tannin also alters arachidonic acid (C20:4) metabolism in these cells. Exposure of rabbit resident alveolar macrophages to condensed tannin results in the time- and dose-dependent release of C20:4 from the membrane phospholipids. The release of C20:4 occurred only at tannin concentrations greater than 25 micrograms/ml and was maximal 90 min after the onset of exposure. The EC50 for release was 75 micrograms/ml. Exposure to 100 micrograms/ml tannin resulted in the release of 20 +/- 3% of the [14C]C20:4 incorporated in the cell membrane. In comparison, exposure to 160 micrograms/ml zymosan resulted in the release of 14 +/- 4% of the [14C]C20:4. For both tannin and zymosan, phosphatidylcholine and phosphatidylinositol were the principal sources of the released C20:4. Approximately 63% of the C20:4 released after zymosan stimulation was further metabolized, mainly via the cyclooxygenase pathway. The major metabolites were 6-keto-prostaglandin F1 alpha, prostaglandin F2 alpha, and prostaglandin E2. In contrast, only 24% of the C20:4 released by tannin was subsequently further metabolized. The metabolites formed were essentially evenly distributed between products of the cyclooxygenase pathway and the lipoxygenase pathway. Exposure of alveolar macrophages to 50 micrograms/ml tannin for 30 min reduced the ability of the cells to subsequently incorporate C20:4 by 50 to 70%. In contrast, exposure of the cells to 160 mg/ml zymosan for 30 min had only a minimal effect on the subsequent ability of these cells to incorporate C20:4. These results indicate that tannin promotes C20:4 release, at least in part, by inhibiting its reacylation back into phospholipids, a mechanism that differs from that of zymosan.

Operational evaluation of three commercial configurations of atropine/HI-6 wet/dry autoinjectors.

Commercially manufactured wet/dry autoinjectors containing atropine in solution and powdered HI-6 were evaluated using HPLC for consistency of drug delivery with various solvation times and stability of drugs postsolvation at a temperature of 40 degrees C. Three configurations of autoinjector were tested. System A (SYS A), with a specified mixing time of 5 sec, delivered a volume of 3.0 ml containing 1.86 mg of atropine sulfate and 443 mg of the bispyridinium oxime HI-6 dichloride. System B1 (SYS B1) and System B2 (SYS B2), with specified mixing times of 40 sec, delivered volumes of 2.3 ml containing 2.13 and 2.06 mg atropine citrate and 424 and 545 mg HI-6 dichloride, respectively. Average coefficients of variation for SYS A were 3.4% for atropine and 5.8% for HI-6 and for SYS B1 and B2 were 5.2% for atropine and 7.0% for HI-6 determinations. Stored from 3 to 14 days at 40 degrees C after the autoinjector contents were mixed, SYS A delivered 1.77 mg atropine sulfate and SYS B1 and B2 delivered 2.02 mg atropine citrate. The delivery of HI-6 dichloride decreased with a half-life of 34 days for SYS A, 39 days for SYS B1, and 32 days for SYS B2. This resulted in a decrease to 90% of the respective day 0 amount after 4 (SYS A) or 5 (SYS B1 or B2) days.

Expression of glutathione S-transferases and cytochrome P450 in normal and tumor breast tissue.

The level of expression of glutathione S-transferases (GSTs) and cytochrome P450s in breast tissue are potentially important determinants in both the susceptibility of this tissue to the mutagenic effects of chemical carcinogens and in the response of breast tumors to chemotherapy. In this study we have investigated the expression of these proteins in 41 tumor and surrounding normal breast tissue samples by measurement of substrate metabolism. Western blot analysis and immunohistochemistry. In addition, we have quantitated the concentration of alpha, mu and pi class GST subunits using radioimmunoassay. All three classes of GST were expressed in breast tissue. The pi and mu class enzymes preponderate. Both the polymorphic mu class GST as well as a further form, present in all individuals, were found in high concentration. The polymorphic mu class GST was expressed in approximately 50% of the samples, which is consistent with the frequency of this polymorphism in the population and therefore does not appear to be a factor in susceptibility to this disease. Interestingly, although levels of the alpha class GST were very low, in two tumor samples extremely high levels of the B1B1 subunit were detected. Immunohistochemical studies showed significant variability in the localization of the pi class of GST between normal epithelial cells, infiltrating plasma cells and tumor cells, and in some samples GST pi appeared to be almost absent from the tumor tissue. No direct, or inverse correlation was found between GST pi concentration determined by radioimmunoassay and estrogen receptor levels. However, when studied by immunohistochemistry estrogen receptor negative tumors did tend to have higher GST pi content. The only cytochrome P450 detectable by Western blot analysis was a member of the P450IIC gene family. This was apparently distinct from the P450IIC proteins expressed in the liver and was detected in normal and tumor tissues to a similar extent.