Risk Factors for Adverse Radiographic Outcomes After Elastic Stable Intramedullary Nailing of Unstable Diaphyseal Tibia Fractures in Children.

OBJECTIVES: Elastic stable intramedullary nails (ESIN) are commonly utilized to treat unstable pediatric tibia fractures but have been associated with complications. The purpose of this study was to identify risk factors for adverse radiographic outcomes after ESIN of pediatric tibia fractures. METHODS: A retrospective review of all patients who underwent diaphyseal tibia fracture stabilization with ESIN between 2010 and 2018 at 3 pediatric level 1 trauma centers was performed. Inclusion criteria were open growth plates, no intra-articular or physeal fracture involvement, and radiographic follow-up until union. Patient demographics, injury mechanism, fracture characteristics, and implant fill relative to the medullary canal were recorded. Radiographic outcome measures included achievement of and time to union, residual angular deformity, and additional procedures. RESULTS: One hundred seventy-two patients met inclusion criteria and were followed for a mean of 1.2 years. Nonunions were observed in 3% of the patient cohort. Another 10% required >6 months to heal, but did not require further surgical intervention. Angular deformities were common with 57% having a residual deformity ≥5 degrees and 14% having a residual deformity ≥10 degrees. Of the patients with a residual deformity between 5 and 10 degrees, 3% were symptomatic, where as 26% of the patients with a residual deformity ≥10 degrees were symptomatic. Greater angular deformities were associated with open fractures, compartment syndrome, and longer time to union. Patient age, weight, tibial comminution, and canal fill were not associated with nonunions or malunions. CONCLUSIONS: ESIN of pediatric tibia fractures results in reliable healing for a majority of patients, but poses risks for residual angular deformities and delayed healing. Open fractures and compartment syndrome were associated with adverse radiographic outcomes.

Social determinants of self-reported health for Canada's indigenous peoples: a public health approach.

OBJECTIVE: In Canada, indigenous peoples suffer from a multitude of health disparities. To better understand these disparities, this study aims to examine the social determinants of self-reported health for indigenous peoples in Canada. STUDY DESIGN: This study uses data from Statistics Canada's Aboriginal Peoples Survey 2012. METHODS: Multinomial logistic regression models were used to examine how selected social determinants of health are associated with self-reported health among off-reserve First Nations and Métis peoples in Canada. RESULTS: Our analysis shows that being older, female, and living in urban settings were significantly associated with negative ratings of self-reported health status among the indigenous respondents. Additionally, we found that higher income and levels of education were strongly and significantly associated with positive ratings of self-reported health status. Compared with indigenous peoples with an education level of grade 8 or lower, respondents with higher education were 10 times (5.35-22.48) more likely to report 'excellent' and 'very good' health. Respondents who earned more than $40,000 annually were three times (2.17-4.72) more likely to report 'excellent' and 'very good' health compared with those who earned less than $20,000 annually. When interacted with income, we also found that volunteering in the community is associated with better self-reported health. CONCLUSIONS: There are known protective determinants (income and education) and risk determinants (location of residence, gender, and age) which are associated with self-reported health status among off-reserve First Nations and Métis peoples. For indigenous-specific determinants, volunteering in the community appears to be associated with self-perceived health status. Thus, addressing these determinants will be necessary to achieve better health outcomes for indigenous peoples in Canada. Next steps include developing indigenous-specific social determinants of health indicators that adequately measure culture, connection, and community.

Multimodal analgesia decreases opioid consumption after shoulder arthroplasty: a prospective cohort study.

BACKGROUND: Studies on perioperative pain control in shoulder arthroplasty focus on regional anesthesia, with little research on other approaches. Perioperative multimodal analgesia regimens decrease opioid intake and opioid-related side effects in lower-extremity arthroplasty. In this study we compare pain scores, opioid consumption, length of stay, and readmission rates in postoperative shoulder arthroplasty patients treated with a standard or multimodal analgesia regimen. METHODS: A prospective cohort analysis was performed at a single institution. Patients undergoing elective shoulder arthroplasty were treated with either a standard opioid-based regimen or a multimodal analgesia regimen perioperatively. Outcome measures included inpatient pain scores, opioid use, length of stay, and 30- and 90-day emergency department visits and readmission rates. RESULTS: Seventy-five patients were included in each cohort. Patients treated with the multimodal analgesia regimen had lower postoperative day 0 pain scores (mean, 1.5 vs 2.2; P = .027). Opioid use in the multimodal cohort was lower on all days: 47% lower on postoperative day 0, 37% on day 1, and 44% on day 2 (all P < .01). The length of inpatient stay was significantly shorter for multimodal patients than for patients treated with the standard regimen (1.44 days vs 1.91 days, P < .01). There was no difference in the rate of 30- or 90-day emergency department visits or readmission. CONCLUSION: Patients undergoing shoulder arthroplasty have decreased postoperative pain and opioid consumption and shorter hospital stays when given a multimodal analgesia regimen. There is no increase in short-term complications or unplanned readmissions, indicating that this is a safe and effective means to control postoperative pain.

Nitrous Oxide and Ammonia Emissions from Injected and Broadcast-Applied Dairy Slurry.

Trade-offs associated with surface application or injection of manure pose important environmental and agronomic concerns. Manure injection can conserve nitrogen (N) by decreasing ammonia (NH) volatilization. However, the injection band also creates conditions that potentially favor nitrous oxide (NO) production: an abundant organic substrate-promoting microbial activity, anaerobic conditions favoring denitrification, and large local concentrations of N. We assessed differences in NH volatilization and NO emissions with broadcast application versus shallow disk injection of dairy slurry during the 2011 to 2013 growing seasons on a well-drained silt loam that received average manure-N application rates of 180 kg N ha via injection or 200 kg N ha via broadcast. Ammonia emissions were measured using a photoacoustic gas analyzer and chambers, and NO emissions were measured using syringes to draw timed samples from vented chambers with analysis by gas chromatograph. Results point to a 92 to 98% (3.02-11.05 kg NH-N ha) reduction in NH volatilization (for the initial sampling) with injection compared with broadcasting manure but also reveal 84 to 152% (725.9-3187.8 g NO-N ha) greater cumulative NO emissions. Although losses of N via NO emission were at least three orders of magnitude less than NH volatilization, their potential role as a greenhouse gas is of concern. Despite the potential greenhouse gas trade-offs associated with shallow disk injection of manure, decreasing NH volatilization provides a substantial benefit, especially to farmers who are trying to conserve N and improve the N/P ratio of soil-applied manure.

Effect of sprouted barley grain supplementation of an herbage-based or haylage-based diet on ruminal fermentation and methane output in continuous culture.

A 4-unit dual-flow continuous-culture fermentor system was used to assess the effect of supplementing 7-d sprouted barley (SB) or barley grain (BG) with an herbage-based or haylage-based diet on nutrient digestibility, volatile fatty acid (VFA) profiles, bacterial protein synthesis, and methane (CH4) output. Treatments were randomly assigned to fermentors in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement using 7 d for diet adaptation and 3 d for sample collection. Experimental diets were (1) 55.5 g of herbage dry matter (DM) + 4.5 g of SB DM, (2) 56.0 g of herbage DM + 4.0 g of BG DM, (3) 55.5 g of haylage DM + 4.5 g of SB DM, and (4) 56.0 g of haylage DM + 4.0 g of BG DM. Forages were fed at 0730, 1030, 1400, and 1900 h, whereas SB and BG were fed at 0730 and 1400 h. Gas samples for CH4 analysis were collected at 0725, 0900, 1000, 1355, 1530, and 1630 h on d 8, 9, and 10. Fluid samples were taken once daily on d 8, 9, and 10 for pH measurements and for ammonia-N and VFA analysis and analyzed for DM, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber for determination of nutrient digestibilities and estimation of bacterial protein synthesis. Orthogonal contrasts were used to compare the effect of forage source (haylage vs. herbage), supplement (BG vs. SB), and the forage × supplement interaction. Apparent and true DM and organic matter digestibilities as well as apparent crude protein digestibility were not affected by forage source. However, true DM digestibility was greatest for diets supplemented with SB. Apparent neutral and acid detergent fiber digestibilities of herbage-based diets were higher than haylage-based diets but fiber digestibility was not affected by supplement. Diets supplemented with SB had higher mean and minimum pH than BG; however, maximum pH was not affected by diet. Supplementation with BG produced a greater concentration of total VFA compared with diets supplemented with SB. Haylage-based diets produced greater CH4 output compared with herbage-based diets but supplementation did not affect CH4 output. Efficiency of bacterial protein synthesis was greater for herbage-based diets compared with haylage-based diets, with no effect of supplementation. Overall, supplementation with SB marginally increased true DM digestibility of herbage- and haylage-based diets but did not affect fiber and crude protein digestibilities, CH4 output, and bacterial efficiency, compared with BG.

In praise of postgraduate career clinics: Translating health professionals' willingness to engagement.

AIM: To capture and retain healthcare staff in postgraduate courses relevant to individual career aspirations, service requirements and continuous practice development (CPD) within an English UK university. DESIGN: Two virtual career clinics for postgraduate practitioners to engage in CPD offers within the university. An online post-enrolment online survey to explore their experiences of engagement with the university. METHODS: Mixed: qualitative and quantitative methods. Engaging 10 participants attended the career clinics, and 42 participants with an online survey. RESULTS: The career clinics were well received by participants who mapped CPD requirements and individual career aspirations. The surveys exposed challenges with marketing and enrolment; however, these were mitigated with support. Four recommendations are presented within this paper applicable to the international postgraduate education of all health practitioners.

Effect of dietary protein concentration on ammonia and greenhouse gas emitting potential of dairy manure.

Two experiments were conducted to investigate the effect of dietary crude protein concentration on ammonia (NH(3)) and greenhouse gas (GHG; nitrous oxide, methane, and carbon dioxide) emissions from fresh dairy cow manure incubated in a controlled environment (experiment 1) and from manure-amended soil (experiment 2). Manure was prepared from feces and urine collected from lactating Holstein cows fed diets with 16.7% (DM basis; HCP) or 14.8% CP (LCP). High-CP manure had higher N content and proportion of NH(3)- and urea-N in total manure N than LCP manure (DM basis: 4.4 vs. 2.8% and 51.4 vs. 30.5%, respectively). In experiment 1, NH(3) emitting potential (EP) was greater for HCP compared with LCP manure (9.20 vs. 4.88 mg/m(2) per min, respectively). The 122-h cumulative NH(3) emission tended to be decreased 47% (P=0.09) using LCP compared with HCP manure. The EP and cumulative emissions of GHG were not different between HCP and LCP manure. In experiment 2, urine and feces from cows fed LCP or HCP diets were mixed and immediately applied to lysimeters (61×61×61 cm; Hagerstown silt loam; fine, mixed, mesic Typic Hapludalf) at 277 kg of N/ha application rate. The average NH(3) EP (1.53 vs. 1.03 mg/m(2) per min, respectively) and the area under the EP curve were greater for lysimeters amended with HCP than with LCP manure. The largest difference in the NH(3) EP occurred approximately 24 h after manure application (approximately 3.5 times greater for HCP than LCP manure). The 100-h cumulative NH(3) emission was 98% greater for HCP compared with LCP manure (7,415 vs. 3,745 mg/m(2), respectively). The EP of methane was increased and that of carbon dioxide tended to be increased by LCP compared with HCP manure. The cumulative methane emission was not different between treatments, whereas the cumulative carbon dioxide emission was increased with manure from the LCP diet. Nitrous oxide emissions were low in this experiment and did not differ between treatments. In the conditions of these experiments, fresh manure from dairy cows fed a LCP diet had substantially lower NH(3) EP, compared with manure from cows fed a HCP diet. The LCP manure increased soil methane EP due to a larger mass of manure added to meet plant N requirements compared with HCP manure. These results represent effects of dietary protein on NH(3) and GHG EP of manure in controlled laboratory conditions and do not account for environmental factors affecting gaseous emissions from manure on the farm.

Effect of incremental flaxseed supplementation of an herbage diet on methane output and ruminal fermentation in continuous culture.

A 4-unit dual-flow continuous culture fermentor system was used to assess the effect of increasing flaxseed (Linum usitatissimum) supplementation of an herbage-based diet on nutrient digestibility, microbial N synthesis, and methane (CH(4)) output. Treatments were randomly assigned to fermentors in a 4 × 4 Latin square design, with 7d for diet adaptation and 3d for data and sample collection. Treatments were 0, 5, 10, and 15% ground flaxseed supplementation of an orchardgrass (Dactylis glomerata L.) diet [70 g of total dry matter (DM) fed daily]. Samples were collected from the fermentors 4 times daily at feeding (0730, 1030, 1400, and 1900 h) on d 8 to 10 of each of four 10-d periods and analyzed for pH, ammonia-N, and volatile fatty acids. Gas samples for CH(4) analysis were collected immediately before and 1 and 2h after the 0730 h feeding on d 8, 9, and 10 and at the 1400 h feeding on d 7, 8, and 9 of each period. Effluents were analyzed for DM, organic matter, crude protein, and neutral detergent fiber for determination of nutrient digestibilities, and for total purine concentration for estimation of microbial protein synthesis. Apparent DM, organic matter, and neutral detergent fiber digestibilities decreased linearly with increasing supplemental flaxseed, whereas true DM and organic matter digestibilities were not significantly affected by treatment, averaging 77.6 and 79.1%, respectively. Mean ruminal pH and concentration of total volatile fatty acids were not significantly affected by increasing the dietary concentration of flaxseed, averaging 6.68 and 55.9 mmol/L across treatments, respectively. However, molar proportions of acetate and propionate increased linearly, whereas those of butyrate and valerate decreased linearly with increasing flaxseed supplementation. Although CH(4) output decreased linearly as supplemental flaxseed increased from 0 to 15% of diet DM, ammonia-N concentration, apparent crude protein digestibility, and microbial N synthesis did not differ across treatments. Incremental ground flaxseed supplementation of an herbage-based diet resulted in a corresponding decrease in CH(4) output in a dual-flow continuous culture fermentor system. However, apparent nutrient digestibility also decreased with flaxseed supplementation, which, at the cow level, could result in decreased DM intake, milk production, or both.

Gabapentin for spasticity and autonomic dysreflexia after severe spinal cord injury.

STUDY DESIGN: Using a complete transection spinal cord injury (SCI) model at the fourth thoracic vertebral level in adult rats, we evaluated whether blocking noxious stimuli below the injury diminishes abnormal somatic and autonomic motor reflexes, manifested in muscular spasticity and hypertensive autonomic dysreflexia, respectively. Gabapentin (GBP) is well tolerated and currently used to manage neuropathic pain in the SCI population; evidence suggests that it acts to decrease presynaptic glutamate release. As clinical evidence indicates that GBP may suppress muscular spasticity in the chronic SCI population, we hypothesized that preventing neurotransmission of noxious stimuli with GBP eliminates a critical physiological link to these distinct, debilitating SCI-induced secondary impairments. OBJECTIVES: Behavioural assessments of tail muscle spasticity and mean arterial blood pressure responses to noxious somatic and/or visceral stimulation were used to test the effects of GBP on these abnormal reflexes. SETTING: Lexington, Kentucky. METHODS: We used femoral artery catheterization and radio-telemetric approaches to monitor blood pressure alterations in response to noxious colorectal distension (CRD) weeks after complete SCI. RESULTS: At 2-3 weeks post-SCI, acute GBP administration (50 mg kg(-1), i.p.) significantly attenuated both autonomic dysreflexia and tail spasticity induced by noxious stimuli compared with saline-treated cohorts. CONCLUSION: These results show, for the first time, that a single-pharmacological intervention, GBP, can effectively attenuate the manifestation of both muscular spasticity and autonomic dysreflexia in response to noxious stimuli.

Environmental and economic comparisons of manure application methods in farming systems.

Alternative methods for applying livestock manure to no-till soils involve environmental and economic trade-offs. A process-level farm simulation model (Integrated Farm System Model) was used to evaluate methods for applying liquid dairy (Bos taurus L.) and swine (Sus scrofa L.) manure, including no application, broadcast spreading with and without incorporation by tillage, band application with soil aeration, and shallow disk injection. The model predicted ammonia emissions, nitrate leaching, and phosphorus (P) runoff losses similar to those measured over 4 yr of field trials. Each application method was simulated over 25 yr of weather on three Pennsylvania farms. On a swine and cow-calf beef operation under grass production, shallow disk injection increased profit by $340 yr(-1) while reducing ammonia nitrogen and soluble P losses by 48 and 70%, respectively. On a corn (Zea mays L.)-and-grass-based grazing dairy farm, shallow disk injection reduced ammonia loss by 21% and soluble P loss by 76% with little impact on farm profit. Incorporation by tillage and band application with aeration provided less environmental benefit with a net decrease in farm profit. On a large corn-and-alfalfa (Medicago sativa L.)-based dairy farm where manure nutrients were available in excess of crop needs, incorporation methods were not economically beneficial, but they provided environmental benefits with relatively low annual net costs ($13 to $18 cow). In all farming systems, shallow disk injection provided the greatest environmental benefit at the least cost or greatest profit for the producer. With these results, producers are better informed when selecting manure application equipment.

Atmospheric Carbon and Transport - America (ACT-America) Data Sets: Description, Management, and Delivery.

The ACT-America project is a NASA Earth Venture Suborbital-2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT-America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower-based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016-2019 over three regions of the US (Mid-Atlantic, Midwest and South) using two NASA research aircraft (B-200 and C-130). We performed three flight patterns (fair weather, frontal crossings, and OCO-2 underflights) and collected more than 1,140 h of airborne measurements via level-leg flights in the atmospheric boundary layer, lower, and upper free troposphere and vertical profiles spanning these altitudes. We also merged various airborne in situ measurements onto a common standard sampling interval, which brings coherence to the data, creates geolocated data products, and makes it much easier for the users to perform holistic analysis of the ACT-America data products. Here, we report on detailed information of data sets collected, the workflow for data sets including storage and processing of the quality controlled and quality assured harmonized observations, and their archival and formatting for users. Finally, we provide some important information on the dissemination of data products including metadata and highlights of applications of ACT-America data sets.

Antigen binding and idiotype analysis of antibodies obtained after electroporation of heavy and light chain genes encoding phosphocholine-specific antibodies: a model for T15-idiotype dominance.

Antibodies bearing the T15 idiotype dominate the murine primary immune response to phosphocholine (PC). Analysis of antigen binding of antibodies derived from V1:DFL16.1:JH1 (VH1) germline and N region-derived variant heavy (H) chains and kappa 22, kappa 24, and kappa 8 light (L) chains demonstrates that the T15H:kappa 22L (T15) antibody binds PC at least 20-40 times better than other antibodies derived from alternate germline forms of the VH1 H chain and kappa 22, kappa 24, or kappa 8 L chains. To achieve affinities in the same range as the T15 antibody, kappa 24 and kappa 8 L chain-containing antibodies must have H chains derived from variant N region or somatically mutated VH1 genes. Single amino acid differences at the VD junction of the various germline and N region variant VH1 H chains dictate the L chain that can associate with the H chain to produce a PC-specific antibody. Several H:L combinations give rise to T15 or M167 idiotype-positive antibodies that lack specificity for PC, and single amino acid substitutions or insertions at the VH1:D junction result in the loss of T15 or M167 idiotopes. Based on these observations, our data support a molecular model involving both preferential gene rearrangement and antigen-driven B cell selection to explain T15 idiotype dominance in the immune response to PC. In the absence of N region diversification, large numbers of neonatal B cells bearing the T15H:kappa 22L surface immunoglobulin M (sIgM) receptors would be selected and expanded by autologous or environmental PC antigen into the long-lived peripheral B cell pool.

Different effects of the Cdx1 and Cdx2 homeobox genes in a murine model of intestinal inflammation.

AIMS: The CDX1 and CDX2 homeoproteins are intestine-specific transcription factors regulating homeostasis. We investigated their relevance in experimentally-induced intestinal inflammation. METHODS: The response to intestinal inflammation induced by dextran sodium sulfate (DSS) was compared in wild type, Cdx1(-/-) and Cdx2(+/-) mice. Intestinal permeability was determined in wild type and Cdx2(+/-) mice. Protein-protein interactions were investigated by co-immunoprecipitation and GST-pulldown, and their functional consequences were assessed using Luciferase reporter systems. RESULTS: Heterozygous Cdx2(+/-) mice, but not Cdx1(-/-) mice, were hypersensitive to DSS-induced acute inflammation as all these mice showed blood in the stools at day 1 of DSS treatment. Hypersensitivity was associated to a 50% higher intestinal permeability. In Cdx2(+/-) mice, the colonic epithelium was repaired during the week after the end of DSS treatment, whereas two weeks were required for wild type animals. Subsequently, no colonic tumour was observed in Cdx2(+/-) mice subjected to 5 repeated cycles of DSS, in contrast to the 2.7 tumours found per wild type mouse. Based on the fact that Smad3(+/-) mice, like Cdx2(+/-) mice, better repair the damaged intestinal epithelium, we found that the CDX2 protein interacts with SMAD3, independently of SMAD4, resulting in a 5-fold stimulation of SMAD3 transcriptional activity. CDX1 also interacted with SMAD3 but it inhibited by 10-fold the SMAD3/SMAD4-dependent transcription. CONCLUSION: The Cdx1 and Cdx2 homeobox genes have distinct effects on the outcome of a pro-inflammatory challenge. This is mirrored by different functional interactions of the CDX1 and CDX2 proteins with SMAD3, a major element of the TGFbeta signalling pathway.

Regulation of beta 1-integrin-mediated cell adhesion by the Cbl adaptor protein.

BACKGROUND: Leukocyte activation results in a rapid increase in adhesion to the extracellular matrix due to the activation of beta 1 integrin receptors. A role for phosphatidylinositol (PI) 3-kinase in integrin activation has been proposed, as activation of integrins by many receptors can be blocked by PI 3-kinase inhibitors. One receptor that regulates integrins is the CD28 surface antigen; here, we investigated the mechanisms responsible for CD28-mediated integrin activation. RESULTS: CD28-mediated integrin activation was blocked by mutation of the binding site for the p85 catalytic subunit of PI 3-kinase in the CD28 cytoplasmic domain, and by expression of a dominant-negative form of the p85 subunit. Substitution of the Src homology 2 (SH2)-binding motif in the CD28 cytoplasmic domain for the corresponding motif in the CD28-related CTLA-4 surface antigen also blocked integrin activation but did not affect the recruitment and activation of PI 3-kinase. Mutations of the CD28 cytoplasmic domain that blocked integrin activation also impaired the tyrosine phosphorylation of the Cbl adaptor protein and the activation of the PI 3-kinase that was associated with Cbl. This Cbl-associated PI 3-kinase was distinct from the PI 3-kinase that coprecipitated with the CD28 cytoplasmic domain. CD28-mediated activation of beta 1 integrins was inhibited by expression of a mutant Cbl protein that shows reduced association with PI 3-kinase. CONCLUSIONS: Cbl is required for PI-3-kinase-dependent regulation of integrin receptors by CD28. Furthermore, CD28 is coupled to two distinct pools of PI 3-kinase, one directly associated with the CD28 cytoplasmic tail and the other associated with Cbl.

Identification of a proline-rich sequence in the CD2 cytoplasmic domain critical for regulation of integrin-mediated adhesion and activation of phosphoinositide 3-kinase.

The CD2 molecule is one of several lymphocyte receptors that rapidly initiates signaling events regulating integrin-mediated cell adhesion. CD2 stimulation of resting human T cells results within minutes in an increase in beta1-integrin-mediated adhesion to fibronectin. We have utilized the HL60 cell line to map critical residues within the CD2 cytoplasmic domain involved in CD2 regulation of integrin function. A panel of CD2 cytoplasmic domain mutants was constructed and analyzed for their ability to upregulate integrin-mediated adhesion to fibronectin. Mutations in the CD2 cytoplasmic domain implicated in CD2-mediated interleukin-2 production or CD2 avidity do not affect CD2 regulation of integrin activity. A proline-rich sequence, K-G-P-P-L-P (amino acids 299 to 305), is essential for CD2-mediated regulation of beta1 integrin activity. CD2-induced increases in beta1 integrin activity could be blocked by two phosphoinositide 3-kinase (PI 3-K) inhibitors or by overexpression of a dominant negative form of the p85 subunit of PI 3-K. In addition, CD2 cytoplasmic domain mutations that abrogate CD2-induced increases in integrin-mediated adhesion also ablate CD2-induced increases in PI 3-K enzymatic activity. Surprisingly, CD2 cytoplasmic domain mutations that inhibit CD2 regulation of adhesion do not affect the constitutive association of the p85 subunit of PI 3-K association with CD2. Mutation of the proline residues in the K-G-P-P-L-P motif to alanines prevented CD2-mediated activation of integrin function and PI 3-K activity but not mitogen-activated protein (MAP) kinase activity. Furthermore, the MEK inhibitor PD 098059 blocked CD2-mediated activation of MAP kinase but had no effect on CD2-induced adhesion. These studies identify a proline-rich sequence in CD2 critical for PI 3-K-dependent regulation of beta1 integrin adhesion by CD2. In addition, these studies suggest that CD2-mediated activation of MAP kinase is not involved in CD2 regulation of integrin adhesion.

Functional interference between thyroid hormone receptor alpha (TRalpha) and natural truncated TRDeltaalpha isoforms in the control of intestine development.

Thyroid hormone is known to participate in the control of intestine maturation at weaning. Its action is mediated by the thyroid hormone nuclear receptors, encoded by the TRalpha and TRbeta genes. Since previous studies have shown that TRbeta plays a minor role in the gut, we focused here our analysis on the TRalpha gene. The TRalpha locus generates the TRalpha1 receptor together with the splicing variant TRalpha2 and the truncated products TRDeltaalpha1 and TRDeltaalpha2, which all lack an intact ligand binding domain. The TRDeltaalpha isoforms are transcribed from an internal promoter located in intron 7, and their distribution is restricted to a few tissues including those of the intestine. In order to define the functions of the different isoforms encoded by the TRalpha locus in the intestinal mucosa, we produced mice either lacking all known TRalpha products or harboring a mutation which inactivates the intronic promoter. We performed a detailed analysis of the intestinal phenotypes in these mice and compared it to that of the previously described TRalpha(-/-) mice, in which TRalpha isoforms are abolished but the TRDeltaalpha isoforms remain. This comparative analysis leads us to the following conclusions: (i) the TRalpha1 receptor mediates the T3-dependent functions in the intestine at weaning time and (ii) the TRDeltaalpha products negatively control the responsiveness of the epithelial cells to T3. Moreover, we show that TRDeltaalpha proteins can interfere with the transcription of the intestine-specific homeobox genes cdx1 and cdx2 and that their activity is regulated by TRalpha1. Altogether these data demonstrate that cooperation of TRalpha and TRDeltaalpha products is essential to ensure the normal postnatal development of the intestine and that mutations in the TRalpha locus can generate different phenotypes caused by the disruption of the equilibrium between these products.

Use of a beta1 integrin-deficient human T cell to identify beta1 integrin cytoplasmic domain sequences critical for integrin function.

T cell activation rapidly and transiently regulates the functional activity of integrin receptors. Stimulation of CD3/T cell receptor, CD2 or CD28, as well as activation with phorbol esters, can induce within minutes an increase in beta1 integrin-mediated adhesion of T cells to fibronectin. In this study, we have produced and utilized a mutant of the Jurkat T cell line, designated A1, that lacks protein and mRNA expression of the beta1 integrin subunit but retains normal levels of CD2, CD3, and CD28 on the cell surface. Activation-dependent adhesion of A1 cells to fibronectin could be restored upon transfection of a wild-type human beta1 integrin cDNA. Adhesion induced by phorbol 12-myristate 13-acetate-, CD3-, CD2-, and CD28 stimulation did not occur if the carboxy-terminal five amino acids of the beta1 tail were truncated or if either of two well-conserved NPXY motifs were deleted. Scanning alanine substitutions of the carboxy-terminal five amino acids demonstrated a critical role for the tyrosine residue at position 795. The carboxy-terminal truncation and the NPXY deletions also reduced adhesion induced by direct stimulation of the beta1 integrin with the activating beta1 integrin-specific mAb TS2/16, although the effects were not as dramatic as observed with the other integrin-activating signals. These results demonstrate a vital role for the amino-terminal NPXY motif and the carboxy-terminal end of the beta1 integrin cytoplasmic domain in activation-dependent regulation of integrin-mediated adhesion in T cells. Furthermore, the A1 cell line represents a valuable new cellular reagent for the analysis of beta1 integrin structure and function in human T cells.

Influence of El Niño on atmospheric CO2 over the tropical Pacific Ocean: Findings from NASA's OCO-2 mission.

Spaceborne observations of carbon dioxide (CO2) from the Orbiting Carbon Observatory-2 are used to characterize the response of tropical atmospheric CO2 concentrations to the strong El Niño event of 2015-2016. Although correlations between the growth rate of atmospheric CO2 concentrations and the El Niño-Southern Oscillation are well known, the magnitude of the correlation and the timing of the responses of oceanic and terrestrial carbon cycle remain poorly constrained in space and time. We used space-based CO2 observations to confirm that the tropical Pacific Ocean does play an early and important role in modulating the changes in atmospheric CO2 concentrations during El Niño events-a phenomenon inferred but not previously observed because of insufficient high-density, broad-scale CO2 observations over the tropics.

The Orbiting Carbon Observatory-2 early science investigations of regional carbon dioxide fluxes.

NASA's Orbiting Carbon Observatory-2 (OCO-2) mission was motivated by the need to diagnose how the increasing concentration of atmospheric carbon dioxide (CO2) is altering the productivity of the biosphere and the uptake of CO2 by the oceans. Launched on 2 July 2014, OCO-2 provides retrievals of the column-averaged CO2 dry-air mole fraction ([Formula: see text]) as well as the fluorescence from chlorophyll in terrestrial plants. The seasonal pattern of uptake by the terrestrial biosphere is recorded in fluorescence and the drawdown of [Formula: see text] during summer. Launched just before one of the most intense El Niños of the past century, OCO-2 measurements of [Formula: see text] and fluorescence record the impact of the large change in ocean temperature and rainfall on uptake and release of CO2 by the oceans and biosphere.