Low-level embryonic crude oil exposure disrupts ventricular ballooning and subsequent trabeculation in Pacific herring

There is a growing awareness that transient, sublethal embryonic exposure to crude oils cause subtle but important forms of delayed toxicity in fish. While the precise mechanisms for this loss of individual fitness are not well understood, they involve the disruption of early cardiogenesis and a subsequent pathological remodeling of the heart much later in juveniles. This developmental cardiotoxicity is attributable, in turn, to the inhibitory actions of crude oil-derived mixtures of polycyclic aromatic compounds (PACs) on specific ion channels and other proteins that collectively drive the rhythmic contractions of heart muscle cells via excitation-contraction coupling. Here we exposed Pacific herring (Clupea pallasi) embryos to oiled gravel effluent yielding ΣPAC concentrations as low as ~ 1 μg/L (64 ng/g in tissues). Upon hatching in clean seawater, and following the depuration of tissue PACs (as evidenced by basal levels of cyp1a gene expression), the ventricles of larval herring hearts showed a concentration-dependent reduction in posterior growth (ballooning). This was followed weeks later in feeding larvae by abnormal trabeculation, or formation of the finger-like projections of interior spongy myocardium, and months later with hypertrophy (overgrowth) of the spongy myocardium in early juveniles. Given that heart muscle cell differentiation and migration are driven by Ca²⁺-dependent intracellular signaling, the observed disruption of ventricular morphogenesis was likely a secondary (downstream) consequence of reduced calcium cycling and contractility in embryonic cardiomyocytes. We propose defective trabeculation as a promising phenotypic anchor for novel morphometric indicators of latent cardiac injury in oil-exposed herring, including an abnormal persistence of cardiac jelly in the ventricle wall and cardiomyocyte hyperproliferation. At a corresponding molecular level, quantitative expression assays in the present study also support biomarker roles for genes known to be involved in muscle contractility (atp2a2, myl7, myh7), cardiomyocyte precursor fate (nkx2.5) and ventricular trabeculation (nrg2, and hbegfa). Overall, our findings reinforce both proximal and indirect roles for dysregulated intracellular calcium cycling in the canonical fish early life stage crude oil toxicity syndrome. More work on Ca²⁺-mediated cellular dynamics and transcription in developing cardiomyocytes is needed. Nevertheless, the highly specific actions of ΣPAC mixtures on the heart at low, parts-per-billion tissue concentrations directly contravene classical assumptions of baseline (i.e., non-specific) crude oil toxicity.

Tracking and Assessing Oil Spill Toxicity to Aquatic Organisms: A Novel Approach

An in situ exposure and effects bioassay system was developed for assessing the toxicity of oil spills to aquatic organisms. The assessment tool combines components of 2 previously developed systems, the sediment ecotoxicity assessment ring (SEA Ring) and the drifting particle simulator. The integrated drifting exposure and effects assessment ring (DEEAR) is comprised of a Global Positioning System (GPS) float, a drifter drogue, the SEA Ring, and the Cyclops-7 fluorescent sensor. Polyethylene passive sampling devices (PED) were mounted for an additional means to characterize water quality conditions and exposures. The DEEAR is optimized for evaluating oil exposure and toxicity in the shallow surface mixing layer of marine waters. A short-term preliminary test was conducted in San Diego, California, USA, to verify the operation of the GPS tracking, the iridium communications, and the integrated SEA Ring exposure system. Further, a proof-of-concept demonstration was conducted offshore in the Santa Barbara Channel, where natural oil seeps produce surface slicks and sheens. Two DEEAR units were deployed for 24 h-one within the oil slick and one in an area outside observable slicks. An aerial drone provided tracking of the surface oil and optimal sites for deployment. The DEEAR proof-of-concept demonstrated integrated real-time tracking and characterization of oil exposures by grab samples, PED, and fluorescent sensors. Oil exposures were directly linked to toxic responses in fish and mysids. This novel integrated system shows promise for use in a variety of aquatic sites to more accurately determine in situ oil exposure and toxicity. Environ Toxicol Chem 2021;40:1452-1462. © 2021 SETAC.

Embryonic Crude Oil Exposure Impairs Growth and Lipid Allocation in a Keystone Arctic Forage Fish

As Arctic ice recedes, future oil spills pose increasing risk to keystone species and the ecosystems they support. We show that Polar cod (Boreogadus saida), an energy-rich forage fish for marine mammals, seabirds, and other fish, are highly sensitive to developmental impacts of crude oil. Transient oil exposures ≥300 μg/L during mid-organogenesis disrupted the normal patterning of the jaw as well as the formation and function of the heart, in a manner expected to be lethal to post-hatch larvae. More importantly, we found that exposure to lower levels of oil caused a dysregulation of lipid metabolism and growth that persisted in morphologically normal juveniles. As lipid content is critical for overwinter survival and recruitment, we anticipate Polar cod losses following Arctic oil spills as a consequence of both near-term and delayed mortality. These losses will likely influence energy flow within Arctic food webs in ways that are as-yet poorly understood.

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Polar cod eggs are buoyant and accumulate crude oil droplets on the chorion

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Crude oil disrupts embryonic cardiac function and larval lipid metabolism

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Juvenile growth and lipid content are reduced following brief embryonic oil exposure

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Polycyclic aromatic hydrocarbons are toxic to cod in parts per trillion concentrations

PAH and OPAH Flux during the Deepwater Horizon Incident

Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water-air boundary was determined. This is the first report of vapor phase and diffusive flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 6.6 and 210 ng/m(3) and 0.02 and 34 ng/m(3) respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air-water flux of 13 individual PAHs was shown to be at least partially influenced by the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi at nominal rates of 56 000 and 42 000 ng/m(2) day(-1) in the summer. Naphthalene was the PAH with the highest observed volatilization rate of 52 000 ng/m(2) day(-1) in June 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air-water chemical flux determinations with passive sampling technology.

Polycyclic aromatic hydrocarbon (PAH) and oxygenated PAH (OPAH) air-water exchange during the deepwater horizon oil spill

Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during, and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water-air boundary was determined. This is the first report of vapor phase and flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m(3) and 0.3 and 27 ng/m(3), respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air-water flux of 13 individual PAHs were strongly associated with the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi in the summer, each nominally 10,000 ng/m(2)/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m(2)/day in September 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air-water chemical flux determinations with passive sampling technology.

Improvements in pollutant monitoring: optimizing silicone for co-deployment with polyethylene passive sampling devices

Sequestering semi-polar compounds can be difficult with low-density polyethylene (LDPE), but those pollutants may be more efficiently absorbed using silicone. In this work, optimized methods for cleaning, infusing reference standards, and polymer extraction are reported along with field comparisons of several silicone materials for polycyclic aromatic hydrocarbons (PAHs) and pesticides. In a final field demonstration, the most optimal silicone material is coupled with LDPE in a large-scale study to examine PAHs in addition to oxygenated-PAHs (OPAHs) at a Superfund site. OPAHs exemplify a sensitive range of chemical properties to compare polymers (log Kow 0.2-5.3), and transformation products of commonly studied parent PAHs. On average, while polymer concentrations differed nearly 7-fold, water-calculated values were more similar (about 3.5-fold or less) for both PAHs (17) and OPAHs (7). Individual water concentrations of OPAHs differed dramatically between silicone and LDPE, highlighting the advantages of choosing appropriate polymers and optimized methods for pollutant monitoring.

Passive sampling coupled to ultraviolet irradiation: a useful analytical approach for studying oxygenated polycyclic aromatic hydrocarbon formation in bioavailable mixtures

The authors investigated coupling passive sampling technologies with ultraviolet irradiation experiments to study polycyclic aromatic hydrocarbon (PAH) and oxygenated PAH transformation processes in real-world bioavailable mixtures. Passive sampling device (PSD) extracts were obtained from coastal waters impacted by the Deepwater Horizon oil spill and Superfund sites in Portland, Oregon, USA. Oxygenated PAHs were found in the contaminated waters with our PSDs. All mixtures were subsequently exposed to a mild dose of ultraviolet B (UVB). A reduction in PAH levels and simultaneous formation of several oxygenated PAHs were measured. Site-specific differences were observed with UVB-exposed PSD mixtures.

An approach for calculating a confidence interval from a single aquatic sample for monitoring hydrophobic organic contaminants

The use of passive sampling devices (PSDs) for monitoring hydrophobic organic contaminants in aquatic environments can entail logistical constraints that often limit a comprehensive statistical sampling plan, thus resulting in a restricted number of samples. The present study demonstrates an approach for using the results of a pilot study designed to estimate sampling variability, which in turn can be used as variance estimates for confidence intervals for future n = 1 PSD samples of the same aquatic system. Sets of three to five PSDs were deployed in the Portland Harbor Superfund site for three sampling periods over the course of two years. The PSD filters were extracted and, as a composite sample, analyzed for 33 polycyclic aromatic hydrocarbon compounds. The between-sample and within-sample variances were calculated to characterize sources of variability in the environment and sampling methodology. A method for calculating a statistically reliable and defensible confidence interval for the mean of a single aquatic passive sampler observation (i.e., n = 1) using an estimate of sample variance derived from a pilot study is presented. Coverage probabilities are explored over a range of variance values using a Monte Carlo simulation.

Bridging environmental mixtures and toxic effects

Biological Response Indicator Devices Gauging Environmental Stressors (BRIDGES) is a bioanalytical tool that combines passive sampling with the embryonic zebrafish developmental toxicity bioassay to provide a quantitative measure of the toxicity of bioavailable complex mixtures. Passive sampling devices (PSDs), which sequester and concentrate bioavailable organic contaminants from the environment, were deployed in the Willamette and Columbia Rivers within and outside of the Portland Harbor Superfund site in Portland, OR, USA. Six sampling events were conducted in the summer and fall of 2009 and 2010. Passive sampling device extracts were analyzed for polycyclic aromatic hydrocarbon (PAH) compounds and screened for 1,201 chemicals of concern using deconvolution-reporting software. The developmental toxicity of the extracts was analyzed using the embryonic zebrafish bioassay. The BRIDGES tool provided site-specific, temporally resolved information about environmental contaminant mixtures and their toxicity. Multivariate modeling approaches were applied to paired chemical and toxic effects data sets to help unravel chemistry-toxicity associations. Modeling elucidated spatial and temporal trends in PAH concentrations and the toxicity of the samples and identified a subset of PAH analytes that were the most highly correlated with observed toxicity. Although the present study highlights the complexity of discerning specific bioactive compounds in complex mixtures, it demonstrates methods for associating toxic effects with chemical characteristics of environmental samples.

Impact of the deepwater horizon oil spill on bioavailable polycyclic aromatic hydrocarbons in Gulf of Mexico coastal waters

An estimated 4.1 million barrels of oil and 2.1 million gallons of dispersants were released into the Gulf of Mexico during the Deepwater Horizon oil spill. There is a continued need for information about the impacts and long-term effects of the disaster on the Gulf of Mexico. The objectives of this study were to assess bioavailable polycyclic aromatic hydrocarbons (PAHs) in the coastal waters of four Gulf Coast states that were impacted by the spill. For over a year, beginning in May 2010, passive sampling devices were used to monitor the bioavailable concentration of PAHs. Prior to shoreline oiling, baseline data were obtained at all the study sites, allowing for direct before and after comparisons of PAH contamination. Significant increases in bioavailable PAHs were seen following the oil spill, however, preoiling levels were observed at all sites by March 2011. A return to elevated PAH concentrations, accompanied by a chemical fingerprint similar to that observed while the site was being impacted by the spill, was observed in Alabama in summer 2011. Chemical forensic modeling demonstrated that elevated PAH concentrations are associated with distinctive chemical profiles.

Estimating risk at a Superfund site using passive sampling devices as biological surrogates in human health risk models

Passive sampling devices (PSDs) sequester the freely dissolved fraction of lipophilic contaminants, mimicking passive chemical uptake and accumulation by biomembranes and lipid tissues. Public Health Assessments that inform the public about health risks from exposure to contaminants through consumption of resident fish are generally based on tissue data, which can be difficult to obtain and requires destructive sampling. The purpose of this study is to apply PSD data in a Public Health Assessment to demonstrate that PSDs can be used as a biological surrogate to evaluate potential human health risks and elucidate spatio-temporal variations in risk. PSDs were used to measure polycyclic aromatic hydrocarbons (PAHs) in the Willamette River; upriver, downriver and within the Portland Harbor Superfund megasite for 3 years during wet and dry seasons. Based on an existing Public Health Assessment for this area, concentrations of PAHs in PSDs were substituted for fish tissue concentrations. PSD measured PAH concentrations captured the magnitude, range and variability of PAH concentrations reported for fish/shellfish from Portland Harbor. Using PSD results in place of fish data revealed an unacceptable risk level for cancer in all seasons but no unacceptable risk for non-cancer endpoints. Estimated cancer risk varied by several orders of magnitude based on season and location. Sites near coal tar contamination demonstrated the highest risk, particularly during the dry season and remediation activities. Incorporating PSD data into Public Health Assessments provides specific spatial and temporal contaminant exposure information that can assist public health professionals in evaluating human health risks.

Deconvolution and chromatic aberration corrections in quantifying colocalization of a transcription factor in three-dimensional cellular space

In the realm of multi-dimensional confocal microscopy, colocalization analysis of fluorescent emission signals has proven to be an invaluable tool for detecting molecular interactions between biological macromolecules at the subcellular level. We show here that image processing operations such as the deconvolution and chromatic corrections play a crucial role in the accurate determination of colocalization between biological macromolecules particularly when the fluorescent signals are faint, and when the fluorescent signals are in the blue and red emission regions. The cellular system presented here describes quantification of an activated forkhead box P3 (FOXP3) transcription factor in three-dimensional (3D) cellular space. 293T cells transfected with a conditionally active form of FOXP3 were stained for anti-FOXP3 conjugated to a fluorescent red dye (Phycoerythrin), and counterstained for DNA (nucleus) with fluorescent blue dye (Hoechst). Due to the broad emission spectra of these dyes, the fluorescent signals were collected only from peak regions and were acquired sequentially. Since the PE signal was weak, a confocal pinhole size of two Airy size was used to collect the 3D image data sets. The raw images supplemented with the spectral data show the preferential association of activated FOXP3 molecules with the nucleus. However, the PE signals were found to be highly diffusive and colocalization quantification from these raw images was not possible. In order to deconvolve the 3D raw image data set, point spread functions (PSFs) of these emissions were measured. From the measured PSF, we found that chromatic shifts between the blue and red colors were quite considerable. Followed by the applications of both the axial and lateral chromatic corrections, colocalization analysis performed on the deconvolved-chromatic corrected-3D image data set showed that 98% of DNA molecules were associated with FOXP3 molecules, whereas only 66% of FOXP3 molecules were colocalized with DNA molecules. In conclusion, our studies clearly demonstrate the importance of PSF measurements, chromatic aberration corrections followed by deconvolution in the accurate determination of transcription factors in the 3D cellular space. The reported imaging and processing methods can be a practical guide for quantitative fluorescence imaging of similar cellular systems and can provide a basis for further development.

Exploiting lipid-free tubing passive samplers and embryonic zebrafish to link site specific contaminant mixtures to biological responses

The Biological Response Indicator Devices Gauging Environmental Stressors (BRIDGES) bio-analytical tool was developed in response to the need for a quantitative technology for assessing the toxicity of environmentally relevant contaminant mixtures. This tool combines passive samplers with the embryonic zebrafish model. When applied in an urban river it effectively linked site specific, bioavailable contaminant mixtures to multiple biological responses. Embryonic zebrafish exposed to extracts from lipid-free passive samplers that were deployed at five locations, within and outside of the Portland Harbor Superfund Megasite, displayed different responses. Six of the eighteen biological responses observed in 941 exposed zebrafish were significantly different between sites. This demonstrates the sensitivity of the bio-analytical tool for detecting spatially distinct toxicity in aquatic systems; bridging environmental exposure to biological response.

CD4+ T-regulatory cells: toward therapy for human diseases

SUMMARY

T-regulatory cells (Tregs) have a fundamental role in the establishment and maintenance of peripheral tolerance. There is now compelling evidence that deficits in the numbers and/or function of different types of Tregs can lead to autoimmunity, allergy, and graft rejection, whereas an over-abundance of Tregs can inhibit anti-tumor and anti-pathogen immunity. Experimental models in mice have demonstrated that manipulating the numbers and/or function of Tregs can decrease pathology in a wide range of contexts, including transplantation, autoimmunity, and cancer, and it is widely assumed that similar approaches will be possible in humans. Research into how Tregs can be manipulated therapeutically in humans is most advanced for two main types of CD4(+) Tregs: forkhead box protein 3 (FOXP3)(+) Tregs and interleukin-10-producing type 1 Tregs (Tr1 cells). The aim of this review is to highlight current information on the characteristics of human FOXP3(+) Tregs and Tr1 cells that make them an attractive therapeutic target. We discuss the progress and limitations that must be overcome to develop methods to enhance Tregs in vivo, expand or induce them in vitro for adoptive transfer, and/or inhibit their function in vivo. Although many technical and theoretical challenges remain, the next decade will see the first clinical trials testing whether Treg-based therapies are effective in humans.

Inducible reprogramming of human T cells into Treg cells by a conditionally active form of FOXP3

FOXP3 is required for the development of Treg and its expression is often used as a surrogate marker of functional suppression. However, it is now known that activated human T effector cells can also express FOXP3 without acquiring regulatory activity. To more closely examine the requirements for FOXP3 to reprogram human T cells into Treg, we developed a conditionally active form of FOXP3 and show here that full acquisition of Treg phenotype and function is strictly dependent on the amount of active FOXP3 a T cell expresses. In addition, the phenotypic and functional alterations induced by FOXP3 are only fully manifested following prolonged induction of protein activity. Induction of FOXP3 activity does not upregulate EBI3 or p35 mRNA, providing evidence that secretion of IL-35 does not substantially contribute to the suppressive mechanism of human Treg. These data represent the first formal evidence that FOXP3 acts as a quantitative regulator rather than a simple molecular switch for Treg.

STAT5-signaling cytokines regulate the expression of FOXP3 in CD4+CD25+ regulatory T cells and CD4+CD25- effector T cells

Forkhead box P3 (FOXP3) is considered a specific marker for CD4(+)CD25(+) regulatory T (Treg) cells, but increasing evidence suggests that human CD4(+)CD25(-) effector T (Teff) cells can transiently express FOXP3 upon activation. We demonstrate that the signal transducer and activator of transcription 5 (STAT5)-signaling cytokines, IL-2, IL-15 and to a lesser extent IL-7, induce FOXP3 up-regulation in vitro in activated human Teff cells. In contrast, cytokines which do not activate STAT5, such as IL-4 or transforming growth factor-beta alone, do not directly induce FOXP3 expression in activated Teff cells. Moreover, expression of a constitutively active form of STAT5a is sufficient to induce FOXP3 expression in Teff cells. Expression of FOXP3 in activated Teff cells requires both TCR-mediated activation and endogenous IL-2, but is not dependent on cell division and does not induce suppressive function. The presence of STAT5-activating cytokines is also required to maintain high FOXP3 expression and suppressive activity of Treg cells in vitro. These data indicate that activation of STAT5 sustains FOXP3 expression in both Treg and Teff cells and contribute to our understanding of how cytokines affect the expression of FOXP3.

Activation-induced FOXP3 in human T effector cells does not suppress proliferation or cytokine production

Forkhead box P3 (FOXP3) is currently thought to be the most specific marker for naturally occurring CD4(+)CD25(+) T regulatory cells (nTregs). In mice, expression of FoxP3 is strictly correlated with regulatory activity, whereas increasing evidence suggests that in humans, activated T effector cells (Teffs) may also express FOXP3. In order to better define the role of FOXP3 in human Teff cells, we investigated the intensity and kinetics of expression in ex vivo Teff cells, suppressed Teff cells and Teff cell lines. We found that all dividing Teff cells expressed FOXP3, but only transiently, and at levels that were significantly lower than those in suppressive nTregs. This temporary expression in Teff cells was insufficient to suppress expression of reported targets of FOXP3 repressor activity, including CD127, IL-2 and IFN-gamma, and was not correlated with induction of a nTreg phenotype. Thus expression of FOXP3 is a normal consequence of CD4(+) T cell activation and, in humans, it can no longer be used as an exclusive marker of nTregs. These data indicate that our current understanding of how FOXP3 contributes to immune tolerance in humans needs to be re-evaluated.

Defective regulatory and effector T cell functions in patients with FOXP3 mutations

The autoimmune disease immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is caused by mutations in the forkhead box protein P3 (FOXP3) gene. In the mouse model of FOXP3 deficiency, the lack of CD4+ CD25+ Tregs is responsible for lethal autoimmunity, indicating that FOXP3 is required for the differentiation of this Treg subset. We show that the number and phenotype of CD4+ CD25+ T cells from IPEX patients are comparable to those of normal donors. CD4+ CD25high T cells from IPEX patients who express FOXP3 protein suppressed the in vitro proliferation of effector T cells from normal donors, when activated by "weak" TCR stimuli. In contrast, the suppressive function of CD4+ CD25high T cells from IPEX patients who do not express FOXP3 protein was profoundly impaired. Importantly, CD4+ CD25high T cells from either FOXP3+ or FOXP3- IPEX patients showed altered suppression toward autologous effector T cells. Interestingly, IL-2 and IFN-gamma production by PBMCs from IPEX patients was significantly decreased. These findings indicate that FOXP3 mutations in IPEX patients result in heterogeneous biological abnormalities, leading not necessarily to a lack of differentiation of CD4+ CD25high Tregs but rather to a dysfunction in these cells and in effector T cells.

Human CD4+ T cells express TLR5 and its ligand flagellin enhances the suppressive capacity and expression of FOXP3 in CD4+CD25+ T regulatory cells

Germline encoded pattern recognition receptors, such as TLRs, provide a critical link between the innate and adaptive immune systems. There is also evidence to suggest that pathogen-associated molecular patterns may have the capacity to modulate immune responses via direct effects on CD4+ T cells. Given the key role of both CD4+CD25+ T regulatory (Treg) cells and the TLR5 ligand flagellin in regulating mucosal immune responses, we investigated whether TLR5 may directly influence T cell function. We found that both human CD4+CD25+ Treg and CD4+CD25- T cells express TLR5 at levels comparable to those on monocytes and dendritic cells. Costimulation of effector T cells with anti-CD3 and flagellin resulted in enhanced proliferation and production of IL-2, at levels equivalent to those achieved by costimulation with CD28. In contrast, costimulation with flagellin did not break the hyporesponsiveness of CD4+CD25+ Treg cells, but rather, potently increased their suppressive capacity and enhanced expression of FOXP3. These observations suggest that, in addition to their APC-mediated indirect effects, TLR ligands have the capacity to directly regulate T cell responses and modulate the suppressive activity of Treg cells.

The role of 2 FOXP3 isoforms in the generation of human CD4+ Tregs

Little is known about the molecules that control the development and function of CD4+ CD25+ Tregs. Recently, it was shown that the transcription factor FOXP3 is necessary and sufficient for the generation of CD4+ CD25+ Tregs in mice. We investigated the capacity of FOXP3 to drive the generation of suppressive CD4+ CD25+ Tregs in humans. Surprisingly, although ectopic expression of FOXP3 in human CD4+ T cells resulted in induction of hyporesponsiveness and suppression of IL-2 production, it did not lead to acquisition of significant suppressor activity in vitro. Similarly, ectopic expression of FOXP3delta2, an isoform found in human CD4+ CD25+ Tregs that lacks exon 2, also failed to induce the development of suppressor T cells. Moreover, when FOXP3 and FOXP3delta2 were simultaneously overexpressed, although the expression of several Treg-associated cell surface markers was significantly increased, only a modest suppressive activity was induced. These data indicate that in humans, overexpression of FOXP3 alone or together with FOXP3delta2 is not an effective method to generate potent suppressor T cells in vitro and suggest that factors in addition to FOXP3 are required during the process of activation and/or differentiation for the development of bona fide Tregs.

Lateralization and motor stereotypy of song production in the brown-headed cowbird

Song production in adult brown-headed cowbirds (Molothrus ater ater) is lateralized, with a slight right syringeal dominance. The left side of the syrinx produces low-frequency (200-2000 Hz) notes within the introductory note clusters, while the right side produces the higher-frequency (1500-6000 Hz) introductory notes, the interphrase unit (10-12 kHz), and the final high-frequency whistle (5-13 kHz). Cross-correlation analyses reveal that individual cowbirds produce each of their four to seven song types with a distinct stereotyped motor pattern--as judged by the patterns of syringeal airflow and subsyringeal pressure. The acoustic differences across song types are reflected in the differences in the bronchial airflow and air sac pressure patterns associated with song production. These motor differences are particularly striking within the second and third introductory note clusters where there is a rapid switching back and forth between the two sides of the syrinx in the production of notes. These motor skills may be especially important in producing behaviorally effective song.

Long-term results with MACOP-B in the treatment of aggressive non-Hodgkin's lymphomas. The experience in Brazil

From October 1984 to December 1989, 59 patients with aggressive non-Hodgkin's lymphomas (diffuse mixed, diffuse large cell, and immunoblastic) were treated with MACOP-B. All patients were previously untreated and most of them had advanced disease. Complete response (CR) was observed in 66%. Actuarial overall survival, failure-free survival (FFS), and relapse-free survival at 8 years were 54%, 52%, and 81%, respectively, with a median follow-up of 76 months (range: 28-92 months). The presence of B symptoms influenced significantly the CR rate, while FFS was affected by B symptoms, bone marrow involvement, and number of extranodal sites. Toxicity was high, with mucositis grade 2 or 3 occurring in 70%, leukopenia grades 3 or 4 in 80%, and death in 11.8% of the patients. MACOP-B was active in the treatment of aggressive non-Hodgkin's lymphomas, mainly in patients with few poor-prognosis factors, but other less toxic regimens would be more appropriate for this population. For poor-prognosis patients, new therapeutic modalities are necessary.

A randomized trial of chemotherapy followed by pelvic radiation therapy in stage IIIB carcinoma of the cervix

Because of the poor results in stage III B carcinoma of the cervix with standard treatment using radiotherapy alone, we designed a randomized trial to determine whether administration of chemotherapy before pelvic irradiation would improve survival. Between May 1984 and August 1986, 107 patients with previously untreated squamous cell carcinoma were randomly assigned, after stratification by age (less than 50 v greater than 50 years), extent of parametrial involvement (unilateral v bilateral), and lymphangiographic findings (negative v positive) to pelvic radiotherapy (RT; arm A) or three cycles of chemotherapy (CT; bleomycin, vincristine, mitomycin, and cisplatin [BOMP]), followed by the same radiotherapy regimen (CT + RT; arm B). The groups were balanced by age, performance status, extent of parametrial involvement, bulkiness of cervical disease, nodal involvement, and presence of hydronephrosis. Minimal follow-up is 34 months. A complete local response was observed in 32.5% of the patients in arm A and in 47% of the patients in arm B (P = .19). Overall 5-year survival rates were 39% for the RT arm and 23% for the CT + RT approach (P = .02). Toxicity was severe in arm B and included fatal pulmonary toxicity in four patients. Locoregional and distant failures were similar in both groups. We conclude that, despite a satisfactory response rate, neoadjuvant BOMP chemotherapy adversely affects survival in stage III B cervical cancer and is associated with unacceptable toxicity.

Feature-based search asymmetries in pigeons and humans

Pigeon and human subjects searched for one target item amidst a number of identical distractors. Simple line forms were used. The target differed from the distractors only in terms of the presence or absence of a feature (a line or a gap); in some experimental series, the feature was present in the target; in others, the feature was in the distractors. The pigeons pecked at the target; the human subjects either reported the presence of the target or pointed to it with a light pen. The time between display onset and this response was recorded. Varied across experimental conditions were the number of distractors in the display, the nature of the stimulus forms, and certain procedural parameters; five conditions were run with pigeons and three with humans. Under all test conditions, the results from the human subjects replicated the previously reported search-asymmetry effect. That is, search speed was greater and decreased less with display size when the target bore the feature (line or gap) than when the distractors bore the feature; both yes/no and localization-response conditions yielded this effect. However, pigeons failed to show search asymmetry; neither line nor gap in a target facilitated search. The results suggest that early visual processing differs for pigeons and humans, that pigeon features differ from human features, or that search asymmetry was eliminated by the long practice given the pigeons.