Deep Learning in Image-Based Plant Phenotyping

A major bottleneck in the crop improvement pipeline is our ability to phenotype crops quickly and efficiently. Image-based, high-throughput phenotyping has a number of advantages because it is nondestructive and reduces human labor, but a new challenge arises in extracting meaningful information from large quantities of image data. Deep learning, a type of artificial intelligence, is an approach used to analyze image data and make predictions on unseen images that ultimately reduces the need for human input in computation. Here, we review the basics of deep learning, assessment of deep learning success, examples of applications of deep learning in plant phenomics, best practices, and open challenges. Expected final online publication date for the Annual Review of Plant Biology, Volume 75 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

A dolabralexin-deficient mutant provides insight into specialized diterpenoid metabolism in maize

Two major groups of specialized metabolites in maize (Zea mays), termed kauralexins and dolabralexins, serve as known or predicted diterpenoid defenses against pathogens, herbivores, and other environmental stressors. To consider the physiological roles of the recently discovered dolabralexin pathway, we examined dolabralexin structural diversity, tissue-specificity, and stress-elicited production in a defined biosynthetic pathway mutant. Metabolomics analyses support a larger number of dolabralexin pathway products than previously known. We identified dolabradienol as a previously undetected pathway metabolite and characterized its enzymatic production. Transcript and metabolite profiling showed that dolabralexin biosynthesis and accumulation predominantly occur in primary roots and show quantitative variation across genetically diverse inbred lines. Generation and analysis of CRISPR-Cas9-derived loss-of-function Kaurene Synthase-Like 4 (Zmksl4) mutants demonstrated dolabralexin production deficiency, thus supporting ZmKSL4 as the diterpene synthase responsible for the conversion of geranylgeranyl pyrophosphate precursors into dolabradiene and downstream pathway products. Zmksl4 mutants further display altered root-to-shoot ratios and root architecture in response to water deficit. Collectively, these results demonstrate dolabralexin biosynthesis via ZmKSL4 as a committed pathway node biochemically separating kauralexin and dolabralexin metabolism, and suggest an interactive role of maize dolabralexins in plant vigor during abiotic stress.

Shielding the oil reserves: the scutellum as a source of chemical defenses

The cereal scutellum is a hub for diverse specialized defense metabolism and pathway discovery.

Bioactive diterpenoids impact the composition of the root-associated microbiome in maize (Zea mays)

Plants deploy both primary and species-specific, specialized metabolites to communicate with other organisms and adapt to environmental challenges, including interactions with soil-dwelling microbial communities. However, the role of specialized metabolites in modulating plant-microbiome interactions often remains elusive. In this study, we report that maize (Zea mays) diterpenoid metabolites with known antifungal bioactivities also influence rhizosphere bacterial communities. Metabolite profiling showed that dolabralexins, antibiotic diterpenoids that are highly abundant in roots of some maize varieties, can be exuded from the roots. Comparative 16S rRNA gene sequencing determined the bacterial community composition of the maize mutant Zman2 (anther ear 2), which is deficient in dolabralexins and closely related bioactive kauralexin diterpenoids. The Zman2 rhizosphere microbiome differed significantly from the wild-type sibling with the most significant changes observed for Alphaproteobacteria of the order Sphingomonadales. Metabolomics analyses support that these differences are attributed to the diterpenoid deficiency of the Zman2 mutant, rather than other large-scale metabolome alterations. Together, these findings support physiological functions of maize diterpenoids beyond known chemical defenses, including the assembly of the rhizosphere microbiome.

Genetic elucidation of interconnected antibiotic pathways mediating maize innate immunity

Specialized metabolites constitute key layers of immunity that underlie disease resistance in crops; however, challenges in resolving pathways limit our understanding of the functions and applications of these metabolites. In maize (Zea mays), the inducible accumulation of acidic terpenoids is increasingly considered to be a defence mechanism that contributes to disease resistance. Here, to understand maize antibiotic biosynthesis, we integrated association mapping, pan-genome multi-omic correlations, enzyme structure-function studies and targeted mutagenesis. We define ten genes in three zealexin (Zx) gene clusters that encode four sesquiterpene synthases and six cytochrome P450 proteins that collectively drive the production of diverse antibiotic cocktails. Quadruple mutants in which the ability to produce zealexins (ZXs) is blocked exhibit a broad-spectrum loss of disease resistance. Genetic redundancies ensuring pathway resiliency to single null mutations are combined with enzyme substrate promiscuity, creating a biosynthetic hourglass pathway that uses diverse substrates and in vivo combinatorial chemistry to yield complex antibiotic blends. The elucidated genetic basis of biochemical phenotypes that underlie disease resistance demonstrates a predominant maize defence pathway and informs innovative strategies for transferring chemical immunity between crops.

Specialized diterpenoid metabolism in monocot crops: Biosynthesis and chemical diversity

Among the myriad specialized metabolites that plants employ to mediate interactions with their environment, diterpenoids form a chemically diverse group with vital biological functions. A few broadly abundant diterpenoids serve as core pathway intermediates in plant general metabolism. The majority of plant diterpenoids, however, function in specialized metabolism as often species-specific chemical defenses against herbivores and microbial diseases, in below-ground allelopathic interactions, as well as abiotic stress responses. Dynamic networks of anti-microbial diterpenoids were first demonstrated in rice (Oryza sativa) over four decades ago, and more recently, unique diterpenoid blends with demonstrated antibiotic bioactivities were also discovered in maize (Zea mays). Enabled by advances in -omics and biochemical approaches, species-specific diterpenoid-diversifying enzymes have been identified in these and other Poaceous species, including wheat (Triticum aestivum) and switchgrass (Panicum virgatum), and are discussed in this article with an emphasis on the critical diterpene synthase and cytochrome P450 monooxygenase families and their products. The continued investigation of the biosynthesis, diversity, and function of terpenoid-mediated crop defenses provides foundational knowledge to enable the development of strategies for improving crop resistance traits in the face of impeding pest, pathogen, and climate pressures impacting global agricultural production.

A Customizable Approach for the Enzymatic Production and Purification of Diterpenoid Natural Products

Diterpenoids form a diverse class of small molecule natural products that are widely distributed across the kingdoms of life and have critical biological functions in developmental processes, interorganismal interactions, and environmental adaptation. Due to these various bioactivities, many diterpenoids are also of economic importance as pharmaceuticals, food additives, biofuels, and other bioproducts. Advanced genomics and biochemical approaches have enabled a rapid increase in the knowledge of diterpenoid-metabolic genes, enzymes, and pathways. However, the structural complexity of diterpenoids and the narrow taxonomic distribution of individual compounds in often only a single species remain constraining factors for their efficient production. Availability of a broader range of metabolic enzymes now provide resources for producing diterpenoids in sufficient titers and purity to facilitate a deeper investigation of this important metabolite group. Drawing on established tools for microbial and plant-based enzyme co-expression, we present an easily operated and customizable protocol for the enzymatic production of diterpenoids in either Escherichia coli or Nicotiana benthamiana, and the purification of desired products via silica chromatography and semi-preparative HPLC. Using the group of maize (Zea mays) dolabralexin diterpenoids as an example, we highlight how modular combinations of diterpene synthase (diTPS) and cytochrome P450 monooxygenase (P450) enzymes can be used to generate different diterpenoid scaffolds. Purified compounds can be used in various downstream applications, such as metabolite structural analyses, enzyme structure-function studies, and in vitro and in planta bioactivity experiments.

Multiple genes recruited from hormone pathways partition maize diterpenoid defences

Duplication and divergence of primary pathway genes underlie the evolution of plant specialized metabolism; however, mechanisms partitioning parallel hormone and defence pathways are often speculative. For example, the primary pathway intermediate ent-kaurene is essential for gibberellin biosynthesis and is also a proposed precursor for maize antibiotics. By integrating transcriptional coregulation patterns, genome-wide association studies, combinatorial enzyme assays, proteomics and targeted mutant analyses, we show that maize kauralexin biosynthesis proceeds via the positional isomer ent-isokaurene formed by a diterpene synthase pair recruited from gibberellin metabolism. The oxygenation and subsequent desaturation of ent-isokaurene by three promiscuous cytochrome P450s and a new steroid 5α reductase indirectly yields predominant ent-kaurene-associated antibiotics required for Fusarium stalk rot resistance. The divergence and differential expression of pathway branches derived from multiple duplicated hormone-metabolic genes minimizes dysregulation of primary metabolism via the circuitous biosynthesis of ent-kaurene-related antibiotics without the production of growth hormone precursors during defence.

Discovery, Biosynthesis and Stress-Related Accumulation of Dolabradiene-Derived Defenses in Maize

Terpenoids are a major component of maize (Zea mays) chemical defenses that mediate responses to herbivores, pathogens, and other environmental challenges. Here, we describe the biosynthesis and elicited production of a class of maize diterpenoids, named dolabralexins. Dolabralexin biosynthesis involves the sequential activity of two diterpene synthases, ENT-COPALYL DIPHOSPHATE SYNTHASE (ZmAN2) and KAURENE SYNTHASE-LIKE4 (ZmKSL4). Together, ZmAN2 and ZmKSL4 form the diterpene hydrocarbon dolabradiene. In addition, we biochemically characterized a cytochrome P450 monooxygenase, ZmCYP71Z16, which catalyzes the oxygenation of dolabradiene to yield the epoxides 15,16-epoxydolabrene (epoxydolabrene) and 3β-hydroxy-15,16-epoxydolabrene (epoxydolabranol). The absence of dolabradiene and epoxydolabranol in Zman2 mutants under elicited conditions confirmed the in vivo biosynthetic requirement of ZmAN2. Combined mass spectrometry and NMR experiments demonstrated that much of the epoxydolabranol is further converted into 3β,15,16-trihydroxydolabrene (trihydroxydolabrene). Metabolite profiling of field-grown maize root tissues indicated that dolabralexin biosynthesis is widespread across common maize cultivars, with trihydroxydolabrene as the predominant diterpenoid. Oxidative stress induced dolabralexin accumulation and transcript expression of ZmAN2 and ZmKSL4 in root tissues, and metabolite and transcript accumulation were up-regulated in response to elicitation with the fungal pathogens Fusarium verticillioides and Fusarium graminearum Consistently, epoxydolabranol significantly inhibited the growth of both pathogens in vitro at 10 µg mL-1, while trihydroxydolabrene-mediated inhibition was specific to Fverticillioides These findings suggest that dolabralexins have defense-related roles in maize stress interactions and expand the known chemical space of diterpenoid defenses as genetic targets for understanding and ultimately improving maize resilience.

ZEB1-repressed microRNAs inhibit autocrine signaling that promotes vascular mimicry of breast cancer cells

During normal tumor growth and in response to some therapies, tumor cells experience acute or chronic deprivation of nutrients and oxygen and induce tumor vascularization. While this occurs predominately through sprouting angiogenesis, tumor cells have also been shown to directly contribute to vessel formation through vascular mimicry (VM) and/or endothelial transdifferentiation. The extrinsic and intrinsic mechanisms underlying tumor cell adoption of endothelial phenotypes, however, are not well understood. Here we show that serum withdrawal induces mesenchymal breast cancer cells to undergo VM and that knockdown of the epithelial-to-mesenchymal transition (EMT) regulator, Zinc finger E-box binding homeobox 1 (ZEB1), or overexpression of the ZEB1-repressed microRNAs (miRNAs), miR-200c, miR-183, miR-96 and miR-182 inhibits this process. We find that secreted proteins Fibronectin 1 (FN1) and serine protease inhibitor (serpin) family E member 2 (SERPINE2) are essential for VM in this system. These secreted factors are upregulated in mesenchymal cells in response to serum withdrawal, and overexpression of VM-inhibiting miRNAs abrogates this upregulation. Intriguingly, the receptors for these secreted proteins, low-density lipoprotein receptor-related protein 1 (LRP1) and Integrin beta 1 (ITGB1), are also targets of the VM-inhibiting miRNAs, suggesting that autocrine signaling stimulating VM is regulated by ZEB1-repressed miRNA clusters. Together, these data provide mechanistic insight into the regulation of VM and suggest that miRNAs repressed during EMT, in addition to suppressing migratory and stem-like properties of tumor cells, also inhibit endothelial phenotypes of breast cancer cells adopted in response to a nutrient-deficient microenvironment.

Functional Characterization of Two Class II Diterpene Synthases Indicates Additional Specialized Diterpenoid Pathways in Maize (Zea mays)

As a major staple food, maize (Zea mays) is critical to food security. Shifting environmental pressures increasingly hamper crop defense capacities, causing expanded harvest loss. Specialized labdane-type diterpenoids are key components of maize chemical defense and ecological adaptation. Labdane diterpenoid biosynthesis most commonly requires the pairwise activity of class II and class I diterpene synthases (diTPSs) that convert the central precursor geranylgeranyl diphosphate into distinct diterpenoid scaffolds. Two maize class II diTPSs, ANTHER EAR 1 and 2 (ZmAN1/2), have been previously identified as catalytically redundant ent-copalyl diphosphate (CPP) synthases. ZmAN1 is essential for gibberellin phytohormone biosynthesis, whereas ZmAN2 is stress-inducible and governs the formation of defensive kauralexin and dolabralexin diterpenoids. Here, we report the biochemical characterization of the two remaining class II diTPSs present in the maize genome, COPALYL DIPHOSPHATE SYNTHASE 3 (ZmCPS3) and COPALYL DIPHOSPHATE SYNTHASE 4 (ZmCPS4). Functional analysis via microbial co-expression assays identified ZmCPS3 as a (+)-CPP synthase, with functionally conserved orthologs occurring in wheat (Triticum aestivum) and numerous dicot species. ZmCPS4 formed the unusual prenyl diphosphate, 8,13-CPP (labda-8,13-dien-15-yl diphosphate), as verified by mass spectrometry and nuclear magnetic resonance. As a minor product, ZmCPS4 also produced labda-13-en-8-ol diphosphate (LPP). Root gene expression profiles did not indicate an inducible role of ZmCPS3 in maize stress responses. By contrast, ZmCPS4 showed a pattern of inducible gene expression in roots exposed to oxidative stress, supporting a possible role in abiotic stress responses. Identification of the catalytic activities of ZmCPS3 and ZmCPS4 clarifies the first committed reactions controlling the diversity of defensive diterpenoids in maize, and suggests the existence of additional yet undiscovered diterpenoid pathways.

Irish strains of Neisseria meningitidis: characterisation using multilocus sequence typing

A total of 56 Neisseria meningitidis strains are analysed using multilocus sequence typing (MLST). Twenty-nine distinct sequence types (STs) were identified, eight of which were new. Four known hypervirulent clones--ST-11 (electrophoretic type [ET]-37) complex, ST-44 complex (lineage 3), ST-32 (ET-5) complex and ST-8 complex (cluster A4)--were identified by MLST in 35 disease-associated and four carrier strains. Two other clones (ST-22 complex and ST-269 complex) were identified in nine disease-associated and one carrier strain. The remaining strains were heterogeneous. Additional sequencing within the FumC gene further distinguished the ET-15 clone within the ST-11 (ET-37) clonal complex. This resolution of isolates into genetic clones by MLST enhances the more traditional techniques of serotyping and serosubtyping. The data obtained established that hyperendemic meningococcal disease in Ireland could be attributed to strains belonging to four major hypervirulent clones, all of which account for elevated levels of disease worldwide. The extra information provided by MLST will be used to study the population structure and epidemiology of N. meningitidis and will allow a comparison of Irish strains with those circulating globally.

Chloroplasts in anther endothecium of Zea mays (Poaceae)

PREMISE OF THE STUDY

Although anthers of Zea mays, Oryza sativa, and Arabidopsis thaliana have been studied intensively using genetic and biochemical analyses in the past 20 years, few updates to anther anatomical and ultrastructural descriptions have been reported. For example, no transmission electron microscopy (TEM) images of the premeiotic maize anther have been published. Here we report the presence of chloroplasts in maize anthers.

METHODS

TEM imaging, electron acceptor photosynthesis assay, in planta photon detection, microarray analysis, and light and fluorescence microscopy were used to investigate the presence of chloroplasts in the maize anther.

KEY RESULTS

Most cells of the maize subepidermal endothecium have starch-containing chloroplasts that do not conduct measurable photosynthesis in vitro.

CONCLUSIONS

The maize anther contains chloroplasts in most subepidermal, endothecial cells. Although maize anthers receive sufficient light to photosynthesize in vivo and the maize anther transcribes >96% of photosynthesis-associated genes found in the maize leaf, no photosynthetic light reaction activity was detected in vitro. The endothecial cell layer should no longer be defined as a complete circle viewed transversely in anther lobes, because chloroplasts are observed only in cells directly beneath the epidermis and not those adjacent to the connective tissue. We propose that chloroplasts be a defining characteristic of differentiated endothecial cells and that nonsubepidermal endothecial cells that lack chloroplasts be defined as a separate cell type, the interendothecium.

Igniting the fire within: a primer on political advocacy for pharmacy professionals

Due to the expanding role of pharmacy in health care, it is imperative that pharmacy professionals work together to advocate for the profession. An English-language only literature search was conducted of the PubMed and Medline databases using the key words advocacy, grassroots, political action committee, lobbying, politics, political action, legislation, letter writing, pharmacy, pharmacist, Capitol Hill. Up-to-date information regarding pharmacy-specific advocacy was limited and difficult to locate. Information from the literature search was supplemented with interviews of professionals actively engaged in advocacy, personal experience, and Web sites of national pharmacy organizations. This primer ignites the fire for political advocacy within pharmacy professionals by reinforcing the significant impact that advocacy has on the profession and by providing information on how to become involved. The primer provides a comprehensive "pocket guide" of resources combined into an easy-to-use reference for pharmacy professionals and outlines a structured approach on how to become a pharmacy advocate, ranging from a minimal level of involvement to master political activist, and to promote interest among pharmacy professionals to become more engaged with advocacy. Even a small act of advocacy or volunteerism can transform a spark into a raging fire.

Primary synovial sarcoma of the kidney. A case report with pathologic appraisal investigation and literature review

Synovial sarcoma (SS) is a soft tissue neoplasm with clearly defined histologic, immunohistochemical and molecular features that usually arises in the extremities of young adults. The occurrence of these tumors in the kidney is extremely rare and have been prevalently described in case reports. The objectives of this work were to evaluate the frequency of primary renal synovial sarcomas and the pathologic progression in recognition of this possibly under-diagnosed entity. A comprehensive review of the literature has also been performed with a focus on survival. We report the clinico-pathological features of an intrarenal SS occurring in a 67-year-old man. The tumour, measuring 4 cm in its greatest diameter, completely replaced the cortex and the medulla of the inferior region of the left kidney compressing the iliopsoas muscle. Radiological imaging was consistent with a renal cell carcinoma. Histologically, the tumour was composed of atypical monotonous vimentin+, CD99+, bcl-2+ spindle cells exhibiting a haphazard fascicular growth pattern and a high mitotic rate (3 to 5 mitoses per HPF). The diagnosis was supported by reverse transcription-polymerase chain reaction which demonstrated SYT-SSX2 gene fusion. The patient was alive with local recurrence of disease 24 months after surgery. Synovial sarcomas occurring in the kidney, in analogy to other sites, tend to have an aggressive biologic behaviour. Despite being extremely uncommon, with only 44 cases reported to date, they should be included in the differential diagnosis of benign and malignant spindle cell tumours of the kidney. This study also emphasizes the importance of a correct pathologic diagnosis for prognostic and therapeutic implications.

Neuroanatomic and behavioral traits for autistic disorders in age-specific restricted index selection mice

The pathogenesis of neurodevelopmental disorders such as autism is believed to be influenced by interactions between genetic and environmental factors, and appropriate animal models are needed to assess the influence of such factors on relevant neurodevelopmental phenotypes. A set of inbred mouse strains (Atchley strains) including A12 (E+L0) and A22 (E-L0) were generated by age-specific restricted index selection from a baseline random-bred ICR mouse population obtained from Harlan Sprague-Dawley [Atchley et al. (1997) Genetics 146(2):629-640; Indianapolis, IN, USA). As compared with the A22 strain, A12 mice had significantly increased early (P0-P10) body weight gain with minimal changes in late (P28-P56) body weight gain. We found that these strains also differed in brain weight, brain volume, cell proliferation, and FGF-2 levels in certain brain regions. Specifically, brain weight and volume were significantly greater in A12 mice than that in A22 mice at P10 and P28. Quantitative analysis of bromodeoxyuridine (BrdU) labeling of proliferating cells showed that the number of BrdU-positive cells in the A12 strain were significantly greater in the frontal cortex and lesser in the dentate gyrus than that in the A22 strain at P28. Western blot revealed that fibroblast growth factors-2 (FGF-2), but not brain-derived neurotrophic factor (BDNF), expression was significantly increased in the frontal cortex of A12 strain at P28. Also, A12 mice exhibited decreased intra-strain social interaction and increased repetitive stereotyped behaviors at P28. Our study suggests that A12 mice may partially mimic the anatomic and behavioral traits of patients with neurodevelopmental disorders such as autism spectrum disorders, and therefore may yield insights into the developmental mechanisms involved in their pathogenesis.

Control of Common Bunt in Organic Wheat

Common bunt, caused by the seedborne and soilborne pathogens Tilletia caries and T. laevis, has re-emerged as a major disease in organic wheat. In conventional agriculture, common bunt is routinely managed with the use of synthetic chemical seed treatments. For this reason, common bunt is a relatively unimportant disease in conventional agriculture. However, since synthetic chemical inputs are prohibited in organic agriculture, common bunt is a major threat once more in organic wheat and seed production. The challenge today is to manage the disease without the use of chemical seed treatments. This review reports on the management of common bunt under organic farming systems, mainly through host resistance and organic seed treatments. We report the history of screening wheat germplasm for bunt resistance, the search for new sources of resistance, and identification and mapping of bunt resistance genes. Since the pathogen has a gene-for-gene relationship with the host, this review also includes a summary of work on pathogen race identification and virulence patterns of field isolates. Also included are studies on the physiological and molecular basis of host resistance. Alternative seed treatments are discussed, including physical seed treatments, and microbial-based and plant-based treatments acceptable in organic systems. The article concludes with a brief discussion on the current gaps in research on the management of common bunt in organic wheat.

Genetic variation in radiation and platinum pathways predicts severe acute radiation toxicity in patients with esophageal adenocarcinoma treated with cisplatin-based preoperative radiochemotherapy: results from the Eastern Cooperative Oncology Group

PURPOSE

Germline genetic variations may partly explain the clinical observation that normal tissue tolerance to radiochemotherapy varies by individual. Our objective was to evaluate the association between single-nucleotide polymorphisms (SNPs) in radiation/platinum pathways and serious treatment-related toxicity in subjects with esophageal adenocarcinoma who received cisplatin-based preoperative radiochemotherapy.

METHODS

In a multicenter clinical trial (E1201), 81 eligible treatment-naïve subjects with resectable esophageal adenocarcinoma received cisplatin-based chemotherapy concurrent with radiotherapy, with planned subsequent surgical resection. Toxicity endpoints were defined as grade ≥3 radiation-related or myelosuppressive events probably or definitely related to therapy, occurring during or up to 6 weeks following the completion of radiochemotherapy. SNPs were analyzed in 60 subjects in pathways related to nucleotide/base excision- or double stranded break repair, or platinum influx, efflux, or detoxification.

RESULTS

Grade ≥3 radiation-related toxicity (mostly dysphagia) and myelosuppression occurred in 18 and 33% of subjects, respectively. The variant alleles of the XRCC2 5' flanking SNP (detected in 28% of subjects) and of GST-Pi Ile-105-Val (detected in 65% of subjects) were each associated with higher odds of serious radiation-related toxicity compared to the major allele homozygote (47% vs. 9%, and 31% vs. 0%, respectively; P = 0.005). No SNP was associated with myelosuppression.

CONCLUSIONS

This novel finding in a well-characterized cohort with robust endpoint data supports further investigation of XRCC2 and GST-Pi as potential predictors of radiation toxicity.

Kinetics of Colonization of Adult Queensland Fruit Flies (Bactrocera tryoni) by Dinitrogen-Fixing Alimentary Tract Bacteria

The average total population of bacteria remained constant in the alimentary tracts of adult laboratory-raised Queensland fruit flies (Bactrocera tryoni) although the insects had ingested large numbers of live bacteria as part of their diet. The mean number of bacteria (about 13 million) present in the gut of the insects from 12 to 55 days after emergence was not significantly modified when, at 5 days after emergence, the flies were fed antibiotic-resistant bacteria belonging to two species commonly isolated from the gut of field-collected B. tryoni. Flies were fed one marked dinitrogen-fixing strain each of either Klebsiella oxytoca or Enterobacter cloacae, and the gastrointestinal tracts of fed flies were shown to be colonized within 7 days by antibiotic-resistant isolates of K. oxytoca but not E. cloacae. The composition of the microbial population also appeared to be stable in that the distribution and frequency of bacterial taxa among individual flies exhibited similar patterns whether or not the flies had been bacteria fed. Isolates of either E. cloacae or K. oxytoca, constituting 70% of the total numbers, were usually dominant, with oxidative species including pseudomonads forming the balance of the population. Antibiotic-resistant bacteria could be spread from one cage of flies to the adjacent surfaces of a second cage within a few days and had reached a control group several meters distant by 3 weeks. Restriction of marked bacteria to the population of one in five flies sampled from the control group over the next 30 days suggested that the bacterial population in the gut of the insect was susceptible to alteration in the first week after emergence but that thereafter it entered a steady state and was less likely to be perturbed by the introduction of newly encountered strains. All populations sampled, including controls, included at least one isolate of the dinitrogen-fixing family Enterobacteriaceae; many were distinct from the marked strains fed to the flies. Nitrogenase activity detected by the acetylene reduction assay was associated with flies fed dinitrogen-fixing bacteria as well as with control groups given either no supplement or free access to a yeast hydrolysate preparation. Nitrogen fixed from the atmosphere may supplement the nutrition of the alimentary tract microbial population of B. tryoni. Transmission electron microscopy showed that the principal site of bacterial colonization in the abdominal alimentary tract was the lumen of the midgut inside the peritrophic membrane. No intracellular symbionts were seen in the gut tissues nor were bacteria found attached to the cuticular folds of the hindgut. The ultrastructure of the gut resembled that of other fly genera except that the intercellular spaces between rectal epithelial cells were more extensive, suggesting a role for unspecialized epithelium in water and solute uptake in B. tryoni.

Solvent–detergent plasma as replacement therapy in a pregnant patient with factor V deficiency

This case illustrates the successful treatment of factor V deficiency in pregnancy using solvent-detergent plasma.

Combined coinhibitory and costimulatory modulation with anti-BTLA and CTLA4Ig facilitates tolerance in murine islet allografts

Complex interactions between positive and negative cosignaling receptors ultimately determine the fate of the immune response. The recently identified coinhibitory receptor, B and T lymphocyte attenuator (BTLA), contributes to regulation of autoimmune and potentially alloimmune responses. We investigated the role of BTLA in a fully major histocompatibility complex-mismatched mouse islet transplant model. We report that anti-BTLA mAb (6F7) alone does not accelerate graft rejection. Rather, while CTLA4Ig alone improved allograft survival, the addition of anti-BTLA mAb to CTLA4Ig led to indefinite (>100 days) allograft survival. Immediately after treatment with anti-BTLA mAb and CTLA4Ig, islet allografts showed intact islets and insulin production despite a host cellular response, with local accumulation of Foxp3+ cells. We clearly demonstrate that combined therapy with anti-BTLA mAb and CTLA4Ig mice induced donor-specific tolerance, since mice accepted a second donor-specific islet graft without further treatment and rejected third party grafts. CTLA4Ig and anti-BTLA mAb limited the initial in vivo proliferation of CFSE-labeled allogeneic lymphocytes, and anti-BTLA mAb enhanced the proportion of PD-1 expressing T cells while depleting pathogenic BTLA+ lymphocytes. We conclude that targeting the BTLA pathway in conjunction with CTLA4Ig costimulatory blockade may be a useful strategy for promoting immunological tolerance in murine islet allografts.

Reliability of a structured assessment for nonclinicians to detect delirium among new admissions to postacute care

OBJECTIVE

To evaluate the interrater reliability of a structured delirium assessment method for nonclinician interviewers in elderly patients newly admitted for postacute care.

DESIGN

Prospective assessment using dyads of nonclinician raters.

SETTING

Postacute (Medicare) units at 6 skilled nursing facilities.

PARTICIPANTS

Forty elderly patients newly admitted for postacute care from medical or surgical units at acute care hospitals.

MEASUREMENTS

Subjects underwent dual delirium assessments within 5 days of admission. The standardized delirium assessment included the Mini-Mental Status Exam and Digit Span to assess overall cognitive function, the Delirium Symptom Interview to elicit specific delirium symptoms, the Memorial Delirium Assessment Scale to measure the severity of delirium, and the Confusion Assessment Method (CAM) to make the diagnosis of delirium. A coding protocol that linked observations to specific coding was used to improve reliability.

RESULTS

The structured delirium assessment process produced very high interobserver agreement for all instruments. Kappa for agreement on delirium diagnosis was 0.95.

CONCLUSIONS

Nonclinician interviewers using a structured delirium assessment achieved reliability that rivaled or exceeded that of trained clinical assessors in other studies. Nonclinicians may offer an effective alternative for the assessment of delirium among postacute patients in skilled nursing facilities.

Addition of aerobic exercise to dietary weight loss preferentially reduces abdominal adipocyte size

OBJECTIVE

To determine if hypocaloric diet, diet plus low-intensity exercise, and diet plus high-intensity exercise differentially influence subcutaneous abdominal and gluteal adipocyte size in obese individuals.

DESIGN

Longitudinal intervention study of hypocaloric diet, diet plus low-intensity exercise, and diet plus high-intensity exercise (calorie deficit = 2800 kcal/week, 20 weeks).

SUBJECTS

Forty-five obese, middle-aged women (BMI = 33.0+/-0.6 kg/m2, age = 58+/-1 years).

MEASUREMENTS

Body composition testing and adipose tissue biopsies were conducted before and after the interventions. Subcutaneous abdominal and gluteal adipocyte size was determined.

RESULTS

All three interventions reduced body weight, fat mass, percent fat, and waist and hip girths to a similar degree. Diet only did not change subcutaneous abdominal adipocyte size, whereas both diet plus exercise groups significantly reduced abdominal adipocyte size. Changes in abdominal adipocyte size in the diet plus exercise groups were significantly different from that of the diet group. Gluteal adipocyte size decreased similarly in all three groups.

CONCLUSION

Addition of exercise training to dietary weight loss preferentially reduces subcutaneous abdominal adipocyte size in obese women. This may be of importance for the treatment of health complications associated with subcutaneous abdominal adiposity.

The RAI-PC: an assessment instrument for palliative care in all settings

Large numbers of persons in most types of healthcare settings have palliative care needs that have considerable impact on their quality of life. Therefore, InterRAI, a multinational consortium of researchers, clinicians, and regulators that uses assessment systems to improve the care of elderly and disabled persons, designed a standardized assessment tool, the Resident Assessment Instrument for Palliative Care (RAI-PC). The RAI-PC can be used for both the design of individual care plans and for case mix and outcomes research. Some elements of this instrument are taken from the resident assessment instrument (RAI) mandated for use in all nursing homes in the United States and widely used throughout the world. The RAI-PC can be used alone or in counjunction with the other assessment tools designed by the InterRAI collaboration: the RAI for homecare (RAI-HC), for acute care (RAI-AC), and for mental health care (RAI-MH). The objective of this study was to field test and carry out reliability studies on the RAI-PC. After appropriate approvals were obtained, the RAI-PC instrument was field tested on 151 persons in three countries in more than five types of settings. Data obtained from 144 of these individuals were analyzed for reliability. The reliability of the instrument was very good, with about 50 percent of the questions having kappa values of 0.8 or higher, and the average kappa value for each of the eight domains ranging from 0.76 to 0.95. The 54 men and 95 women had a mean age of 79 years. Thirty-four percent of individuals suffered pain daily. Eighty percent tired easily; 52 percent were breathless on exertion; and 19 to 53 percent had one or more other symptoms, including change in sleep pattern, dry mouth, nausea and vomiting, anorexia, breathlessness at rest, constipation, and diarrhea. The number of symptoms an individual reported increased as the estimated time until death declined. The "clinician friendly" RAI-PC can be used in multiple sites of care to facilitate both care planning and case mix and outcomes research.

Immediate-early gene response to methamphetamine, haloperidol, and quinolinic acid is not impaired in Huntington's disease transgenic mice

Striatal neurons in symptomatic Huntington's disease (HD) transgenic mice are resistant to a variety of toxic insults, including quinolinic acid (QA), kainic acid and 3-nitropropionic acid. The basis for this resistance is currently unknown. To investigate the possibility that the immediate-early gene (IEG) response is defective in symptomatic HD mice leading to a lack of response to these compounds, we examined the expression of c-Fos and Krox 24 after administration of the indirect dopamine agonist methamphetamine, the dopamine D(2) receptor antagonist haloperidol and the neurotoxin QA in 5- and 10-week-old R6/2 transgenic HD and wild-type mice. Unlike wild-type and pre-symptomatic R6/2 transgenic HD mice, 10-week-old symptomatic HD mice were resistant to methamphetamine-induced gliosis and QA lesion. There was, however, no difference in the number or distribution of c-Fos-immunoreactive nuclei 2 hr after single injections of methamphetamine or haloperidol among 5- and 10-week-old wild-type mice and 5- and 10-week-old R6/2 HD mice. Similarly, despite their resistance to QA-induced lesioning and lower basal levels of krox-24 mRNA, the symptomatic R6/2 mice had equivalent increases in the amount of c-fos and krox-24 mRNA compared to wild-type and pre-symptomatic R6/2 HD mice as determined by in situ hybridization and densitometry 2 hr after QA administration. These data demonstrate that the c-Fos and Krox 24 IEG response to dopamine agonists, dopamine antagonists and neurotoxic insult is functional in symptomatic R6/2 HD mice. Resistance to toxic insult in R6/2 mice may be conferred by interactions of mutant huntingtin with proteins or transcriptional processes further along the toxic cascade.

Friend of GATA-1 represses GATA-3-dependent activity in CD4+ T cells

The development of naive CD4+ T cells into a T helper (Th) 2 subset capable of producing interleukin (IL)-4, IL-5, and IL-13 involves a signal transducer and activator of transcription (Stat)6-dependent induction of GATA-3 expression, followed by Stat6-independent GATA-3 autoactivation. The friend of GATA (FOG)-1 protein regulates GATA transcription factor activity in several stages of hematopoietic development including erythrocyte and megakaryocyte differentiation, but whether FOG-1 regulates GATA-3 in T cells is uncertain. We show that FOG-1 can repress GATA-3-dependent activation of the IL-5 promoter in T cells. Also, FOG-1 overexpression during primary activation of naive T cells inhibited Th2 development in CD4+ T cells. FOG-1 fully repressed GATA-3-dependent Th2 development and GATA-3 autoactivation, but not Stat6-dependent induction of GATA-3. FOG-1 overexpression repressed development of Th2 cells from naive T cells, but did not reverse the phenotype of fully committed Th2 cells. Thus, FOG-1 may be one factor capable of regulating the Th2 development.

MRP1 gene expression level regulates the death and differentiation response of neuroblastoma cells

We have previously reported a strong correlation between poor prognosis in childhood neuroblastoma (NB) patients and high-level expression of the transmembrane efflux pump, Multidrug Resistance-associated Protein (MRP1), in NB tumour tissue. In this study, we inhibited the endogenous expression of MRP1 in 2 different NB tumour cell lines by stably transfecting an MRP1 antisense expression vector (MRP-AS). Compared with control cells, MRP-AS transfectant cells demonstrated a higher proportion of dead and morphologically apoptotic cells, spontaneous neuritogenesis, and, increased synaptophysin and neurofilament expression. Bcl-2 protein expression was markedly reduced in MRP-AS cells compared to controls. Conversely, we found that the same NB tumour cell line overexpressing the full-length MRP1 cDNA in sense orientation (MRP-S) demonstrated resistance to the neuritogenic effect of the differentiating agent, all-trans-retinoic acid. Taken together, the results suggest that the level of MRP1 expression in NB tumour cells may influence the capacity of NB cells for spontaneous regression in vivo through cell differentiation and death.

A review of techniques for the investigation of otitis externa and otitis media

Otitis externa, inflammation of the externa ear canal, is relatively easy to diagnose based on the history and physical examination findings. The diagnosis of otitis media, inflammation of the middle ear cavity, is more challenging, with the work-up being both costly and, at times, invasive. The pathogenesis of otitis externa has been classified into predisposing, primary, and perpetuating factors. It is critical to the management of ear disease that the clinician recognize and investigate which factors are contributing to each individual patient's ear disease. Failure to identify and address the primary and/or predisposing factors is the most common cause of chronic recurrent otitis externa. Chronic inflammation of the ear canal leads to the development of the perpetuating factors, which may be the major reason for treatment failure, regardless of the primary cause of the ear disease. In this article, the predisposing, primary, and perpetuating factors involved in ear disease will be presented, along with a review of the techniques used in the diagnosis of otitis externa and otitis media.

Racial and state differences in the designation of advance directives in nursing home residents

OBJECTIVES

To examine racial and state differences in the use of advance directives and surrogate decision-making in a nursing home population.

DESIGN

A retrospective cohort study.

SETTING

Nursing homes in the states of California (CA), Massachusetts (MA), New York (NY), and Ohio (OH).

PARTICIPANTS

Nursing home residents: 130,308 in CA, 59,691 in MA, 112,080 in NY, and 98,954 in OH.

MEASUREMENTS

Minimum Data Set information concerning resident race and whether or not residents have a living will (LW), a do not resuscitate (DNR) order, or a surrogate decision-maker (SDM).

RESULTS

The proportion of LWs, DNR orders, and SDMs varied significantly (P < .0001) by racial categories in each state. In general, whites were distinctly different from other racial categories. Whites were significantly more likely to have a LW (odds ratio (OR) = 1.9 (CA), OR = 2.2 (NY), OR = 4.9 (OH)), a DNR order (OR = 2.4 (CA), OR = 2.4 (MA), OR = 3.3 (NY), OR = 3.2 (OH)), and a SDM (OR = 1.1 (CA), OR = 1.2 (NY), OR = 1.6 (OH)) than were nonwhites, after adjusting for potentially confounding factors. Significant state differences (P < .0001) were observed in LWs, DNR orders, and SDMs and were most pronounced in residents of Ohio, who were significantly more likely to have a LW than were residents in other states (OR = 9.3).

CONCLUSIONS

Various resident characteristics explain some of the racial differences, although whites are still more likely to have a LW, a DNR order, or an SDM independent of various resident characteristics included in the adjusted analyses. This pattern is observed in all states, although the ORs varied by state. Some of these differences may be due to distinct cultural approaches to end-of-life care and lack of knowledge and understanding of advance directives. The distinctly higher rates of LWs among all racial groups in Ohio than in other states suggest that states can potentially increase the use of advance directives through intervention.

Unexpected characteristics of the IFN-gamma reporters in nontransformed T cells

Analysis of the IFN-gamma promoter has primarily been conducted by transient expression of reporter constructs in transformed cells. However, the activity of cis elements may differ when expressed transiently compared with their activity within native chromatin. Furthermore, the transcription factors and signaling mechanisms in transformed cells may differ from those in normal T cells. To analyze IFN-gamma promoter regulation in normal T cells, we developed a novel retroviral bottom-strand reporter system to allow the chromatin integration of promoter regions in primary developing T cells. As controls, both the IL-2 and IL-4 promoters were inducible in this system, with the IL-4 reporter having Th2-specific activity. Strikingly, the IFN-gamma promoter exhibited constitutive activity in both Th1 and Th2 subsets, in contrast to the behavior of the endogenous IFN-gamma gene, which is inducible only in Th1 cells. In mapping this activity, we found that the AP-1/GM-CSF site in the distal promoter element is the most critical element for the constitutive activity. Transgenic reporter lines for the IFN-gamma promoter confirmed the constitutive behavior of the isolated IFN-gamma promoter. This constitutive activity was resistant to inhibition by cyclosporin A and was independent of Stat4 and p38 mitogen-activated protein kinase. These results suggest that IFN-gamma promoter regulation may require cis elements residing either downstream or >3.4 kb upstream of the transcriptional start site, involving repression of constitutive activity.

Immune system dysfunction and autoimmune disease in mice lacking Emk (Par-1) protein kinase

Emk is a serine/threonine protein kinase implicated in regulating polarity, cell cycle progression, and microtubule dynamics. To delineate the role of Emk in development and adult tissues, mice lacking Emk were generated by targeted gene disruption. Emk(-/-) mice displayed growth retardation and immune cell dysfunction. Although B- and T-cell development were normal, CD4(+)T cells lacking Emk exhibited a marked upregulation of the memory marker CD44/pgp-1 and produced more gamma interferon and interleukin-4 on stimulation through the T-cell receptor in vitro. In addition, B-cell responses to T-cell-dependent and -independent antigen challenge were altered in vivo. As Emk(-/-) animals aged, they developed splenomegaly, lymphadenopathy, membranoproliferative glomerulonephritis, and lymphocytic infiltrates in the lungs, parotid glands and kidneys. Taken together, these results demonstrate that the Emk protein kinase is essential for maintaining immune system homeostasis and that loss of Emk may contribute to autoimmune disease in mammals.

Structure and specificity of GATA proteins in Th2 development

Development of Th2 subset of CD4+ T cells involves the interleukin-4 (IL-4)- and Stat6-dependent increase in GATA-3 expression during primary activation. Recently we reported that the phenotypic stability and factor independence of Th2 cells involves acquisition of an intracellular pathway that maintains GATA-3 expression. Evidence from retroviral expression studies implied that this pathway involved an autoactivation of GATA-3 expression, since Stat6-deficient T cells induced endogenous GATA-3 when infected with GATA-3-expressing retroviruses. That study left unresolved the issue of whether GATA-3 autoactivation was direct or indirect. Several other Th2-specific transcription factors have been described, including c-Maf and JunB. We therefore examined the ability of these other transcription factors to induce GATA-3 expression and promote Th2 development. Neither c-Maf nor JunB induced Th2 development in Stat6-deficient CD4+ T cells, in contrast to GATA-3. Consistent with this indication of a possible direct autoactivation pathway, we also observed that heterologous GATA family proteins GATA-1, GATA-2, and GATA-4 were also capable of inducing GATA-3 expression in developing Stat6-deficient T cells and promote Th2 development. Mutational analysis revealed evidence for two distinct mechanisms of GATA-3 action. IL-4 induction by GATA-3 required each of the functional domains to be present, whereas repression of gamma interferon could occur even when mutants of GATA-3 lacking the second transactivation domain, TA2, were expressed. The GATA-dependent induction of the GATA-3 but not the other GATA genes in T cells suggests that T-cell-specific cis elements within the GATA-3 locus likely cooperate with a general GATA recognition motif to allow GATA-3-dependent autoactivation.

Stability and commitment in T helper cell development

Specialized effector activities that are required to eliminate various pathogens involve cytokines produced by specialized CD4(+) T cells subsets, dogmatically termed Th1 and Th2 cells. Despite some oversimplifications, this paradigm is useful for organizing the complex pathways that control forward and backward movements along the road of T cell differentiation. Effective immune memory relies, in part, on the maintenance of the T helper phenotype. This review will address basic issues that relate to the maintenance or reversibility of Th1/Th2 states within the CD4(+) T cell lineage.

ACVR1B (ALK4, activin receptor type 1B) gene mutations in pancreatic carcinoma

DPC4 is known to mediate signals initiated by type beta transforming growth factor (TGFbeta) as well as by other TGFbeta superfamily ligands such as activin and BMP (bone morphogenic proteins), but mutational surveys of such non-TGFbeta receptors have been negative to date. Here we describe the gene structure and novel somatic mutations of the activin type I receptor, ACVR1B, in pancreatic cancer. ACVR1B has not been described previously as a mutated tumor-suppressor gene.

IL-18-stimulated GADD45 beta required in cytokine-induced, but not TCR-induced, IFN-gamma production

Interleukin-12 (IL-12) and IL-18 induce synergistic transcription of interferon gamma (IFN-gamma) that is T cell receptor (TCR)-independent, not inhibited by cyclosporin A and requires new protein synthesis. To characterize this pathway, we screened for genes that are induced in IL-12- and IL-18-treated T helper type 1 cells. GADD45 beta, which activates mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase kinase 4 (MEKK4), was induced by IL-18 and augmented by IL-12. GADD45 beta expression in naïve CD4+ T cells activated p38 MAPK and selectively increased cytokine-induced, but not TCR-induced, IFN-gamma production. Kinase-inactive MEKK4 and inhibition of the p38 MAPK pathway both selectively inhibit cytokine-induced, but not TCR-induced, IFN-gamma production. Thus, the synergy between IL-12 and IL-18 may involve GADD45 beta induction, which can maintain the MEKK4 and p38 MAPK activation that is necessary for cytokine-induced, but not TCR-induced, IFN-gamma production.

Characterization of the inflammatory infiltrate during IgE-mediated late phase reactions in the skin of normal and atopic dogs

In canine and human atopic patients, the intracutaneous injection of offending allergens is followed by the development of both immediate and late-phase reactions. The present study was performed to expand on the characterization and dynamics of inflammatory cell subsets during IgE-mediated late-phase reactions in canine skin. Three normal dogs and three Dermatophagoides farinae-allergic dogs were selected for this experiment. All dogs were challenged intradermally with mite allergen, purified anticanine IgE antibodies (positive control) or phosphate-buffered saline (negative control). Skin biopsies were obtained before and 6, 12 and 24 h post-injection. Sections were stained with metachromatic and eosinophil-specific histological stains. Additionally, we used an immunohistochemical method with antibodies specific for canine leukocyte antigens. This study confirmed the occurrence of a late-phase reaction in atopic skin following allergen challenge, and in normal and atopic canine skin after intradermal injection of IgE-specific antibodies. Whereas early emigrating dermal cells were composed chiefly of neutrophil and activated eosinophil granulocytes, there was an influx of alpha beta T-lymphocytes and dermal dendritic cells in later stages of the late-phase reactions. Because IgE-mediated late-phase reactions resemble spontaneous atopic canine skin lesions, both at macroscopic and microscopic levels, we propose the use of similar challenges to study the anti-inflammatory effects of anti-allergic drugs in a pre-clinical setting.

Development of cytochrome oxidase blobs in visual cortex of normal and visually deprived cats

Cytochrome oxidase (CO) blobs are central to our understanding of the columnar organization and parallel pathways in primate and cat visual cortex. In primates, development of blobs and their relationship with other columnar features of the visual cortex begins pre-natally, before visual experience. In kittens, the supragranular layers differentiate post-natally, after eye opening, raising the possibility that visual experience may influence the development of blobs in cat V1. We have examined the development of blobs in unfolded and flattened sections through the visual cortex of normally reared, dark-reared, monocularly deprived and binocularly deprived kittens. Blobs were found in superficial layers of V1 of normally reared kittens as early as 2 weeks of age, although at this age the overall CO staining in V1 was lighter than in V2. By 6 weeks of age the blobs were adult-like. A patchy pattern of CO staining was also found in V2 of young kittens but not in adults. Visual experience was not necessary for expression of the blobs and monocularly deprived kittens had well developed blobs, indicating that strong Y cell drive is not necessary for the development of blobs in cat V1. CO blobs appear in kitten V1 very early in post-natal development and their expression is independent of visual experience, suggesting that they may be an intrinsic feature of V1 organization.

Splenomegaly, hypersplenism and coagulation abnormalities in liver disease

Splenomegaly is a frequent finding in patients with liver disease. It is usually asymptomatic but may cause hypersplenism. Thrombocytopenia is the most frequent manifestation of hypersplenism and may contribute to portal hypertension related bleeding. A number of therapies are available for treating thrombocytopenia due to hypersplenism including splenectomy, partial splenectomy, partial splenic embolization, TIPS etc. None is entirely satisfactory. Hypersplenism usually improves following liver transplantation. Therapy with cytokines such as thrombopoietin may offer hope for the future. Patients with liver disease also have abnormalities in coagulation. This is not surprising as all coagulation proteins (except for von willebrand factor vWF) and most inhibitors of coagulation are synthesized in the liver. Genetic or acquired abnormalities of coagulation may predispose to thrombosis of the hepatic or portal veins with significant clinical sequelae. An understanding of the mechanisms involved in coagulation and thrombosis is valuable in choosing from the increasing treatment options available. These include clotting factors, haemeostatic drugs and newer therapies such as recombinant factor VIIa. Splenic artery aneurysms are the most common visceral artery aneurysms in man. Rupture is frequently catastrophic. These aneurysms are being increasingly recognized in liver transplant patients and require treatment before or during transplant surgery.

Role of the Stat4 N domain in receptor proximal tyrosine phosphorylation

Stat4 is activated by the cytokines interleukin 12 and alpha interferon (IFN-alpha) and plays a significant role in directing development of naïve CD4(+) T cells to the Th1 phenotype. Signal transducers and activators of transcription (STAT) proteins undergo phosphorylation on a conserved tyrosine residue, resulting in homo- and heterodimerization, nuclear translocation, and DNA binding. Stat4 can bind to single IFN-gamma-activated sites (GASs) as a dimer or bind two tandem GASs as a pair of STAT dimers, or tetramer, stabilized through N-terminal domain (N domain) interactions between dimers. We uncovered an unexpected effect of the Stat4 N domain in controlling the proximal activation of Stat4 by tyrosine phosphorylation at activated receptor complexes. Mutation of the N domain at tryptophan residue W37, predicted to interrupt N domain dimer formation, unexpectedly prevented IFN-alpha-induced tyrosine phosphorylation of the Stat4 monomer, blocking dimer formation and nuclear translocation. Furthermore, N domains appear to exert private STAT functions, since interchanging the N domains between Stat1 and Stat4 prevented receptor-mediated tyrosine phosphorylation in one case and interrupted STAT-specific gene activation in another. Finally, replacement of the N domain of Stat1 with that of Stat4 abrogated the normal Stat2 dependence of Stat1 phosphorylation, again suggesting the domains are not equivalent. Thus, in addition to its role in STAT tetramerization, the conserved STAT N domain appears to participate in very proximal steps of receptor-mediated ligand-induced tyrosine phosphorylation.

The process of restructuring and the treatment of obesity in women

Obesity is a prevalent health behavior that is difficult to treat because of its complexity, constraints on provider time, and negligible insurer reimbursement. In this comparative case study the authors describe two obese women's weight loss and lifestyle change efforts while enrolled in a nine-month, multidisciplinary weight loss program. The researchers conducted three semistructured interviews during six months. Eight major themes were identified: (1) support networks. (2) internalization/externalization, (3) routines, (4) relapse, (5) change in perspective, (6) reward/punishment, (7) emotional issues, and (8) life balance. These themes parallel Johnson's three-stage theory of cognitive restructuring. (See Johnson, 1990, "Restructuring: An Emerging Theory on the Process of Losing Weight." Journal of Advanced Nursing, 15, 1289-1296.) Researchers reveal that complex health problems are replete with social and psychological factors that may undermine treatment success. Understanding a client's experience while attempting behavior change is crucial for the development of interventions that address difficult and costly health behaviors.

Dendritic cell regulation of TH1-TH2 development

Understanding the control exerted by cytokines on T helper cell subsets 1 and 2 (TH1-TH2) development has progressed to a fairly satisfying knowledge of intracellular signals and transcription factors. Less is understood about the molecular basis of TH1-TH2 development exerted by other parameters, such as how the antigen presenting cell can influence this process. Recent work suggests that dendritic cell subsets contribute significant polarizing influences on T helper differentiation, but how this comes about is less clear. In some cases known pathways may be used, as in the dendritic cell subset 1 exerting TH1 polarization by interleukin 12 (IL-12) production and STAT4 activation. In others, the effects are still in need of explanation.