Prophylactic mesh augmentation in emergency laparotomy closure: a meta-analysis of randomized controlled trials with trial sequential analysis.

BACKGROUND: Prophylactic mesh augmentation in emergency laparotomy closure is controversial. We aimed to perform a meta-analysis of randomized controlled trials (RCT) evaluating the placement of prophylactic mesh during emergency laparotomy. METHODS: We performed a systematic review of Cochrane, Scopus, and PubMed databases to identify RCT comparing prophylactic mesh augmentation and no mesh augmentation in patients undergoing emergency laparotomy. We excluded observational studies, conference abstracts, elective surgeries, overlapping populations, and trial protocols. Postoperative outcomes were assessed by pooled analysis and meta-analysis. Statistical analysis was performed using RevMan 5.4. Heterogeneity was assessed with I2 statistics. Risk of bias was assessed using the revised Cochrane risk-of-bias tool (RoB 2). The review protocol was registered at PROSPERO (CRD42023412934). RESULTS: We screened 1312 studies and 33 were thoroughly reviewed. Four studies comprising 464 patients were included in the analysis. Mesh reinforcement was significantly associated with a decrease in incisional hernia incidence (OR 0.18; 95% CI 0.07-0.44; p < 0.001; I2 = 0%), and synthetic mesh placement reduced fascial dehiscence (OR 0.07; 95% CI 0.01-0.53; p = 0.01; I2 = 0%). Mesh augmentation was associated with an increase in operative time (MD 32.09 min; 95% CI 6.39-57.78; p = 0.01; I2 = 49%) and seroma (OR 3.89; 95% CI 1.54-9.84; p = 0.004; I2 = 0%), but there was no difference in surgical-site infection or surgical-site occurrences requiring procedural intervention or reoperation. CONCLUSIONS: Mesh augmentation in emergency laparotomy decreases incisional hernia and fascial dehiscence incidence. Despite the risk of seroma, prophylactic mesh augmentation appears to be safe and might be considered for emergency laparotomy closure. Further studies evaluating long-term outcomes are still needed.

Real-World Outcomes With Lurbinectedin in Second-Line Setting and Beyond for Extensive Stage Small Cell Lung Cancer.

BACKGROUND: Lurbinectedin has emerged as a potential treatment option for relapsed small cell lung cancer (SCLC). While clinical trials have demonstrated its efficacy and safety, real-world data are limited. This study aimed to evaluate the safety and efficacy of lurbinectedin in a real-world setting, focusing on its use as a second-line agent and beyond in SCLC patients. METHODS: A retrospective analysis was conducted on 90 patients who received lurbinectedin between June 2020 and June 2022 within the Mayo Clinic Health System. Of these, 50 patients received lurbinectedin as a second-line agent, and 14 patients received it as a third-line or later agent. The primary outcomes assessed were overall survival (OS), progression-free survival (PFS), and treatment-related adverse events. RESULTS: Lurbinectedin was generally well tolerated in this real-world cohort, with a median OS of 5.1 months in the second-line cohort and 5.6 months in the third-line or later cohort. Median PFS was 2.1 months in the second-line cohort and 3.4 months in the third-line or later cohort. Adverse events were manageable, with the most common being neutropenia, anemia, fatigue, and febrile neutropenia. No treatment-related deaths or grade 5 toxicities were reported. CONCLUSION: This real-world study provides valuable insights into the safety and efficacy of lurbinectedin in relapsed SCLC. Lurbinectedin demonstrated modest efficacy and a comparable safety profile to that observed in clinical trials. However, outcomes for relapsed SCLC remain suboptimal, particularly for patients with a shorter chemotherapy-free interval and central nervous system metastases.

Glyceryl triacetate for Canavan disease: a low-dose trial in infants and evaluation of a higher dose for toxicity in the tremor rat model.

Canavan disease (CD) is a fatal dysmyelinating genetic disorder associated with aspartoacylase deficiency, resulting in decreased brain acetate levels and reduced myelin lipid synthesis in the developing brain. Here we tested tolerability of a potent acetate precursor, glyceryl triacetate (GTA), at low doses in two infants diagnosed with CD, aged 8 and 13 months. Much higher doses of GTA were evaluated for toxicity in the tremor rat model of CD. GTA was given orally to the infants for up to 4.5 and 6 months, starting at 25 mg/kg twice daily, doubling the dose weekly until a maximum of 250 mg/kg reached. Wild-type and tremor rat pups were given GTA orally twice daily, initially at a dose of 4.2 g/kg from postnatal days 7 through 14, and at 5.8 g/kg from day 15 through 23, and thereafter in food (7.5%) and water (5%). At the end of the trial (approximately 90 to 120 days) sera and tissues from rats were analysed for changes in blood chemistry and histopathology. GTA treatment caused no detectable toxicity and the patients showed no deterioration in clinical status. In the high-dose animal studies, no significant differences in the mean blood chemistry values occurred between treated and untreated groups, and no lesions indicating toxicity were detectable in any of the tissues examined. Lack of GTA toxicity in two CD patients in low-dose trials, as well as in high-dose animal studies, suggests that higher, effective dose studies in human CD patients are warranted.

Socioeconomic status predicts functional disability in patients participating in a back pain trial.

PURPOSE: To investigate whether socioeconomic status in patients with back pain participating in a randomised controlled trial was predictive of functional disability (Roland Disability Questionnaire, RDQ). METHOD: Secondary analysis of data (n = 949) from a national primary care trial of physical treatments for back pain (UKBEAM trial) using multilevel modelling. The three indicators were Townsend scores, educational levels and work status. RESULTS: All indicators were significant predictors of outcome after adjusting for baseline variables. As Townsend scores increased (indicating greater deprivation) RDQ scores (functional disability related to back pain) increased. Lower levels of educational attainment were associated with higher RDQ scores. Those 'Not in Work' reported markedly higher levels of RDQ scores which increased over time. There was no evidence that one particular treatment was more suitable for participants of different socioeconomic status. CONCLUSIONS: The findings from this study add to the body of literature which suggests the importance of socioeconomic factors as an influence on health, including resultant disability related to chronic musculoskeletal conditions such as back pain. Work status was particularly dominant in our findings and may suggest that helping patients with back pain back to work where appropriate, is an especially important part of the management process.

Psychopharmacological treatment of non-comorbid and comorbid pervasive developmental disorder and pediatric bipolar disorder.

There is little information on the treatment of comorbid bipolar disorder and pervasive developmental disorder (PDD) in youth. This paper will provide a review of the literature on appropriate psychopharmacological treatment strategies for bipolar disorder and PDD in children and adolescents and make recommendations for psychopharmacological treatment and monitoring of the comorbid presentation of these two disorders. The purpose of this paper is to provide clinicians with evidence-based research findings of treatment strategies used by the experts in the field of pediatric bipolar disorder and PDD. Sources for the study have been published reviews and research articles. Studies addressing the complex treatment issues of comorbid pediatric bipolar disorder and PDD are limited. Research studies have demonstrated improvement in psychiatric functioning of children and adolescents with bipolar disorder and PDDs who took atypical antipsychotics and mood stabilizers. Children with bipolar disorder have benefited the most from the combination of a mood stabilizer plus an antipsychotic. However, there are no studies looking at combined medication treatments for PDD. Children who manifest both disorders could possibly benefit from this combination. While selective serotonin reuptake and tricyclic antidepressants inhibitors have demonstrated improvement in PDD symptoms, they should be used with caution in children who have comorbid bipolar symptoms as they can cause agitation, mania or, in a limited number of cases, serotonin reuptake inhibitors have increased suicidal behavior. More extensive, long-term research is needed to find better treatments to improve quality of life and outcomes in this difficulty to treat population.

Timely diagnosis of comorbid pervasive developmental disorder and bipolar disorder.

Little is known about the overlapping symptoms and comorbidity of pediatric bipolar disorder (BD) and pervasive developmental disorders (PDD) in youth. The aim of this study was to clearly differentiate the symptoms, understand the prevalence and patterns of comorbid presentations, as well as to provide a summary of evidence-based research findings to improve timely diagnosis and treatment for comorbid PDD and BD in children and adolescents, and to provide clinicians with evidence-based research findings of the similarity and differences in symptom presentation, the epidemiology, and diagnostic strategies used by experts in the fields of PDD and pediatric BD. The sources for this study were published review and research articles. According to the results obtained, it can be observed that studies evaluating the epidemiology, symptom presentation and diagnosis of comorbid BD and PDD are limited. However, research studies identified a clear overlap in symptoms between the two disorders and the existence of comorbid PDD and BD. Children with PDD and comorbid BD may be significantly impaired. More extensive research is needed to facilitate timely diagnosis and treatment to improve quality of life and outcomes in this population.

Randomized trial of two physiotherapy interventions for primary care back and neck pain patients: cost effectiveness analysis.

OBJECTIVES: To assess the cost-effectiveness of a brief physiotherapy pain management approach using cognitive-behavioural principles (Solution-Finding Approach) when compared with a commonly used traditional method of physical therapy (McKenzie Approach). METHODS: Economic evaluation conducted alongside a randomized trial. The study related incremental differences in costs and benefits associated with the Solution Finding and McKenzie approaches over 12 months. Costs were measured in UK pounds sterling. Benefit was measured as health-related quality of life using the EQ-5D, which was used to estimate patient-specific quality adjusted life years (QALYs). RESULTS: The McKenzie treatment required, on average, one extra physiotherapist visit (4.15 vs 3.10). Over a 12-month period, Solution Finding was associated with a lower per patient cost of pound-24.4 (95% CI pound-49.6 to 0.789 pounds). The mean difference in QALYs between the two groups was -0.020 (95% CI -0.057 to 0.017); favouring those receiving McKenzie. Relating incremental mean costs and QALYs gave an incremental cost effectiveness ratio of 1220 pounds (-24.4/-0.020) suggesting the McKenzie treatment is cost effective. CONCLUSIONS: Results suggest that the additional cost associated with the McKenzie treatment when compared with the Solution Finding Approach may be worth paying, given the additional benefit the approach seems more likely to provide. Further research is needed to assess the extent to which the difference in physiotherapy visits between the two strategies is generalizable to other treatment settings.

Randomized trial of two physiotherapy interventions for primary care neck and back pain patients: 'McKenzie' vs brief physiotherapy pain management.

OBJECTIVES: Interventions that take psychosocial factors into account are recommended for patients with persistent back or neck pain. We compared the effectiveness of a brief physiotherapy pain management approach using cognitive-behavioural principles (Solution-Finding Approach-SFA) with a commonly used method of physical therapy (McKenzie Approach-McK). METHODS: Eligible patients referred by GPs to physiotherapy departments with neck or back pain lasting at least 2 weeks were randomized to McK (n= 161) or to SFA (n= 154). They were further randomized to receive an educational booklet or not. The primary outcome was the Tampa Scale of Kinesiophobia (TSK) (Activity-Avoidance scale used as a proxy for coping) at 6 weeks, and 6 and 12 months. RESULTS: Of 649 patients assessed for eligibility, 315 were recruited (219 with back pain, 96 with neck pain). There were no statistically significant differences in outcomes between the groups, except that at any time point SFA patients supported by a booklet reported less reliance on health professionals (Multidimensional Health Locus of Control Powerful Others Scale), while at 6 months McK patients showed slightly more improvement on activity-avoidance (TSK). At 6 weeks, patient satisfaction was greater for McK (median 90% compared with 70% for SFA). Both interventions resulted in modest but clinically important improvements over time on the Roland Disability Questionnaire Scores and Northwick Park Neck Pain Scores. CONCLUSIONS: The McK approach resulted in higher patient satisfaction overall but the SFA could be more cost-effective, as fewer (three vs four) sessions were needed.

Phosphonate utilization by the globally important marine diazotroph Trichodesmium.

The factors that control the growth and nitrogen fixation rates of marine diazotrophs such as Trichodesmium have been intensively studied because of the role that these processes have in the global cycling of carbon and nitrogen, and in the sequestration of carbon to the deep sea. Because the phosphate concentrations of many ocean gyres are low, the bioavailability of the larger, chemically heterogeneous pool of dissolved organic phosphorus could markedly influence Trichodesmium physiology. Here we describe the induction, by phosphorus stress, of genes from the Trichodesmium erythraeum IMS101 genome that are predicted to encode proteins associated with the high-affinity transport and hydrolysis of phosphonate compounds by a carbon-phosphorus lyase pathway. We show the importance of these genes through expression analyses with T. erythraeum from the Sargasso Sea. Phosphonates are known to be present in oligotrophic marine systems, but have not previously been considered to be bioavailable to marine diazotrophs. The apparent absence of genes encoding a carbon-phosphorus lyase pathway in the other marine cyanobacterial genomes suggests that, relative to other phytoplankton, Trichodesmium is uniquely adapted for scavenging phosphorus from organic sources. This adaptation may help to explain the prevalence of Trichodesmium in low phosphate, oligotrophic systems.

Patient perceptions of physical therapy within a trial for back pain treatments (UK BEAM) [ISRCTN32683578].

OBJECTIVES: To explore the views of participants in a randomized controlled trial of physical treatments for low back pain about the treatment packages they received in the trial. METHODS: Within a randomized controlled trial that found small to moderate benefits from adding a manipulation package or an exercise programme to general practice care, we elicited participants' views on the treatment using an open question in participant questionnaires. These data were analysed using an adapted framework approach. RESULTS: We received a total of 1259 comments from 1334 participants. Participants randomized to usual general practice care reported dissatisfaction with receiving only 'usual care', which consisted of providing analgesic medication without providing an explanation for their pain. Those randomized to a manipulation package felt the intervention was appropriate to their needs and commonly reported striking benefits. Participants assigned to the exercise programme developed a sense of self-reliance in managing back pain, although some failed to be sufficiently motivated to continue their exercise regimen outside the classes. CONCLUSIONS: This qualitative analysis has found much clearer differences between the groups than the main quantitative analysis. This suggests that some of the added value from being allocated to additional physical treatment for low back pain is not being captured by existing methods of measurement. Improved methods of assessment that consider a wider range of domains may be needed when interpreting the added value of such treatments to individual patients.

The role of physiotherapy in the management of non-specific back pain and neck pain.

This paper provides an overview of best practice for the role of physiotherapy in managing back pain and neck pain, based mainly on evidence-based guidelines and systematic reviews. More up-to-date relevant primary research is also highlighted. A stepped approach is recommended in which the physiotherapist initially takes a history and carries out a physical examination to exclude any potentially serious pathology and identify any particular functional deficits. Initially, advice providing simple messages of explanation and reassurance will form the basis of a patient education package. Self-management is emphasized throughout. A return to normal activities is encouraged. For the patient who is not recovering after a few weeks, a short course of physiotherapy may be offered. This should be based on an active management approach, such as exercise therapy. Manual therapy should also be considered. Any passive treatment should only be used if required to relieve pain and assist in helping patients get moving. Barriers to recovery need to be explored. Those few patients who have persistent pain and disability that interferes with their daily lives and work need more intensive treatment or a different approach. A multidisciplinary approach may then be optimal, although it is not widely available. Liaison with the workplace and/or social services may be important. Getting all players on side is crucial, especially at this stage.

DNA fragmentation in leukocytes following subacute low-dose nerve agent exposure.

The objective of the present study was to determine levels of DNA fragmentation in blood leukocytes from guinea pigs by single-cell gel electrophoresis (comet assay) after exposure to the chemical warfare nerve agent (CWNA), soman, at doses ranging from 0.1 LD50 to 0.4 LD50, once per day for either 5 or 10 days. Post-exposure recovery periods ranged from 0 to 17 days. Leukocytes were imaged from each animal, and the images analyzed by computer. Data obtained for exposure to soman demonstrated significant increases in DNA fragmentation in circulating leukocytes in CWNA-treated guinea pigs compared with saline-injected control animals at all doses and time points examined. Notably, significantly increased DNA fragmentation was observed in leukocytes 17 days after cessation of soman exposure. Our findings demonstrate that leukocyte DNA fragmentation assays may provide a sensitive biomarker for low-dose CWNA exposure.

Treatment with the snail peptide CGX-1007 reduces DNA damage and alters gene expression of c-fos and bcl-2 following focal ischemic brain injury in rats.

Delayed cell death following ischemic brain injury has been linked to alterations in gene expression. In this study we have evaluated the upregulation of several genes associated with delayed cell death (c-fos, bax, and bcl-2) during the initial 24 h of transient middle cerebral artery occlusion (MCAo) in the rat and the effects of postinjury treatment with the NR2B subunit specific NMDA receptor antagonist CGX-1007 (Conantokin-G, Con-G). C-fos mRNA levels peaked at 1 h postinjury in both cortical and subcortical ischemic brain regions (30-fold increase), remained elevated at 4 h and returned to within normal, preinjury levels 24 h postinjury. The increase in mRNA levels correlated to increased protein expression in the entire ipsilateral hemisphere at 1 h. Regions of necrosis at 4 h were void of C-Fos immunoreactivity with continued upregulation in surrounding regions. At 24 h, loss of C-Fos staining was observed in the injured hemisphere except for sustained increases along the border of the infarct and in the cingulate cortex of vehicle treated rats. CGX-1007 treatment reduced c-fos expression throughout the infarct region by up to 50%. No significant differences were measured in either bcl-2 or bax mRNA expression between treatment groups. However, at 24 h postinjury CGX-1007 treatment was associated with an increase in Bcl-2 immunoreactivity that correlated to a reduction in DNA fragmentation. In conclusion, CGX-1007 effectively attenuated gene expression associated with delayed cell death as related to a neuroprotective relief of cerebral ischemia.

UK Back pain Exercise And Manipulation (UK BEAM) trial--national randomised trial of physical treatments for back pain in primary care: objectives, design and interventions [ISRCTN32683578].

BACKGROUND: Low back pain has major health and social implications. Although there have been many randomised controlled trials of manipulation and exercise for the management of low back pain, the role of these two treatments in its routine management remains unclear. A previous trial comparing private chiropractic treatment with National Health Service (NHS) outpatient treatment, which found a benefit from chiropractic treatment, has been criticised because it did not take treatment location into account. There are data to suggest that general exercise programmes may have beneficial effects on low back pain. The UK Medical Research Council (MRC) has funded this major trial of physical treatments for back pain, based in primary care. It aims to establish if, when added to best care in general practice, a defined package of spinal manipulation and a defined programme of exercise classes (Back to Fitness) improve participant-assessed outcomes. Additionally the trial compares outcomes between participants receiving the spinal manipulation in NHS premises and in private premises. DESIGN: Randomised controlled trial using a 3 x 2 factorial design. METHODS: We sought to randomise 1350 participants with simple low back pain of at least one month's duration. These came from 14 locations across the UK, each with a cluster of 10-15 general practices that were members of the MRC General Practice Research Framework (GPRF). All practices were trained in the active management of low back pain. Participants were randomised to this form of general practice care only, or this general practice care plus manipulation, or this general practice care plus exercise, or this general practice care plus manipulation followed by exercise. Those randomised to manipulation were further randomised to receive treatment in either NHS or private premises. Follow up was by postal questionnaire one, three and 12 months after randomisation. The primary analysis will consider the main treatment effects before interactions between the two treatment packages. Economic analysis will estimate the cost per unit of health utility gained by adding either or both of the treatment packages to general practice care.

Spinal manipulation for low-back pain: a treatment package agreed to by the UK chiropractic, osteopathy and physiotherapy professional associations.

Trials of manipulative treatment have been compromised by, amongst other things, different definitions of the therapeutic procedures involved. This paper describes a spinal manipulation package agreed by the UK professional bodies that represent chiropractors, osteopaths and physiotherapists. It was devised for use in the UK Back pain Exercise And Manipulation (UK BEAM) trial--a national study of physical treatments in primary care funded by the Medical Research Council and the National Health Service Research and Development Programme. Although systematic reviews have reported some beneficial effects of spinal manipulation for low-back pain, due to the limited methodological quality of primary studies and difficulties in defining manipulation, important questions have remained unanswered. The UK BEAM trial was designed to answer some of those questions. Early in the design of the trial, it was acknowledged that the spinal manipulation treatment regimes provided by practitioners from the three professions shared more similarities than differences. Because the trial design specifically precluded comparison of the effect between the professions, it was necessary to devise a homogenous package representative of, and acceptable to, all three. The resulting package is 'pragmatic', in that it represents what happens to most people undergoing manipulation, and 'explanatory' in that it excludes discipline-specific variations and other ancillary treatments.

Effect of the proteasome inhibitor MLN519 on the expression of inflammatory molecules following middle cerebral artery occlusion and reperfusion in the rat.

Anti-inflammatory treatment with the proteasome inhibitor MLN519 has been previously reported to be neuroprotective against ischemic brain injury in rats. These effects have been related to inhibition of the transcription factor NF-kappaB, which is activated through ubiquitin-proteasomal degradation. The aim of this study was to evaluate the effects of MLN519 to alter the expression of several inflammatory genes under the control of NF-kappaB. Male Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAo) followed by vehicle or MLN519 (1.0 g/kg, i.v.) treatment immediately after reperfusion of blood to the brain at 2h. Gene expression was evaluated 3-72 h post-MCAo. The most striking effects of intravenous treatment with MLN519 were associated with reductions in ICAM-1 expression at 3 h followed by reductions in E-selectin (12-72 h). Less dramatic reductions were observed in IL-1Beta (3-24 h) and TNF-Alpha (24 h) with no apparent effects on IL-6 and VCAM-1 mRNA levels. Immunohistochemical analysis revealed that the genes most dramatically affected by MLN519 had highest expression in endothelial cells and leukocytes (E-selectin, ICAM-1),indicating that these cell types may be the primary targets of intravenously delivered MLN519 treatment.

Phosphorylation of the serine 60 residue within the Cdx2 activation domain mediates its transactivation capacity.

BACKGROUND & AIMS: Cdx2 is critical in intestinal proliferation and differentiation. Modulation of Cdx2 function in response to cellular signaling is to be elucidated. We hypothesize that phosphorylation of the Cdx2 activation domain can modulate its function. METHODS: The Cdx2 activation domain was delineated in transient transfections using different portions of Cdx2 fused to the Gal4-DNA binding domain. In vivo phosphorylation was studied by metabolic labeling with (32)P-orthophosphate. To study a potential phosphorylation site, polyclonal antibodies were generated: CNL was raised against amino acids 54-66 of Cdx2 and P-Cdx2-S60 against the same epitope in which serine 60 was phosphorylated. RESULTS: A critical region for transactivation resides within amino acids 60-70. Substitution of serine 60 with alanine reduces incorporation of (32)P-orthophosphate substantially. S60-phosphorylation decreases Cdx2 transactivation. Phosphorylation of serine 60 can be inhibited with the mitogen-activated protein kinase inhibitors PD98059 or UO126. P-Cdx2-S60 recognizes phosphorylated serine 60 mainly in proliferative compartment of the intestinal epithelial layer. In contrast, CNL recognizes Cdx2 predominantly in the differentiated compartment. CONCLUSIONS: The Cdx2 activation domain is phosphorylated at serine 60 via the mitogen-activated protein kinase pathway. S60-phosphorylated and S60-nonphosphorylated Cdx2 have different transcriptional activity, as well as different spatial expression patterns in the intestinal epithelium.

Transsexual limb transplants in fiddler crabs and expression of novel sensory capabilities.

We used transsexual limb transplants in fiddler crabs to examine how peripheral sensory structures interact with the central nervous system (CNS) to produce a sexually dimorphic behavior. Female and male chemosensory feeding claws were transplanted onto male hosts in place of nonfeeding, nonchemosensory claws. Successfully transplanted claws retain donor morphologies and contain chemosensory neurons. Neurons in successfully transplanted female feeding claws express the enhanced sensitivity to chemical cues seen in female, but not male, neurons in claws of normal animals. When chemically stimulated, the transplanted claws evoke feeding behavior not observed in normal males, even though the sensory neurons in the transplanted limb project to the host's sexually dimorphic neuropil not known to receive chemosensory input. Behavioral sensitivity is directly related to the sensitivity of peripheral neurons in the transplanted feeding claw. Thus, the interactions between peripheral neurons and their targets may restructure the CNS so that novel sensory capabilities are expressed, and this can produce sexually dimorphic behaviors.

Iron stress in open-ocean cyanobacteria (Synechococcus, Trichodesmium, and Crocosphaera spp.): identification of the IdiA protein.

Cyanobacteria are prominent constituents of the marine biosphere that account for a significant percentage of oceanic primary productivity. In an effort to resolve how open-ocean cyanobacteria persist in regions where the Fe concentration is thought to be limiting their productivity, we performed a number of Fe stress experiments on axenic cultures of marine Synechococcus spp., Crocosphaera sp., and Trichodesmium sp. Through this work, we determined that all of these marine cyanobacteria mount adaptive responses to Fe stress, which resulted in the induction and/or repression of several proteins. We have identified one of the Fe stress-induced proteins as an IdiA homologue. Genomic observations and laboratory data presented herein from open-ocean Synechococcus spp. are consistent with IdiA having a role in cellular Fe scavenging. Our data indicate that IdiA may make an excellent marker for Fe stress in open-ocean cyanobacterial field populations. By determining how these microorganisms respond to Fe stress, we will gain insight into how and when this important trace element can limit their growth in situ. This knowledge will greatly increase our understanding of how marine Fe cycling impacts oceanic processes, such as carbon and nitrogen fixation.