Urban and rural differences in out-of-hospital cardiac arrest in Ireland

BACKGROUND

More than a third of Ireland's population lives in a rural area, defined as the population residing in all areas outside clusters of 1500 or more inhabitants. This presents a challenge for the provision of effective pre-hospital resuscitation services. In 2012, Ireland became one of three European countries with nationwide Out-of-Hospital Cardiac Arrest (OHCA) register coverage. An OHCA register provides an ability to monitor quality and equity of access to life-saving services in Irish communities.

AIM

To use the first year of national OHCAR data to assess differences in the occurrence, incidence and outcomes of OHCA where resuscitation is attempted and the incident is attended by statutory Emergency Medical Services between rural and urban settings.

METHODS

The geographical coordinates of incident locations were identified and co-ordinates were then classified as 'urban' or 'rural' according to the Irish Central Statistics Office (CSO) definition.

RESULTS

1798 OHCA incidents were recorded which were attended by statutory Emergency Medical Services (EMS) and where resuscitation was attempted. There was a higher percentage of male patients in rural settings (71% vs. 65%; p = 0.009) but the incidence of male patients did not differ significantly between urban and rural settings (26 vs. 25 males/100,000 population/year p = 0.353). A higher proportion of rural patients received bystander cardiopulmonary resuscitation (B-CPR) 70% vs. 55% (p ≤ 0.001), and had defibrillation attempted before statutory EMS arrival (7% vs. 4% (p = 0.019), respectively). Urban patients were more likely to receive a statutory EMS response in 8 min or less (33% vs. 9%; p ≤ 0.001). Urban patients were also more likely to be discharged alive from hospital (6% vs. 3%; p = 0.006) (incidence 2.5 vs. 1.1/100,000 population/year; p ≤ 0.001). Multivariable analysis of survival showed that the main variable of interest i.e. urban vs. rural setting was also independently associated with discharge from hospital alive (OR 3.23 (95% CI 1.43-7.31)).

CONCLUSION

There are significant disparities in the incidence of resuscitation attempts in urban and rural areas. There are challenges in the provision of services and subsequent outcomes from OHCA that occur outside of urban areas requiring novel and innovative solutions. An integrated community response system is necessary to improve metrics around OHCA response and outcomes in rural areas.

Synergistic induction of human cathelicidin antimicrobial peptide gene expression by vitamin D and stilbenoids

SCOPE

The cathelicidin antimicrobial peptide (CAMP) gene is induced by 1α,25-dihydroxyvitamin D3 (1α,25(OH)2 D3), lithocholic acid, curcumin, nicotinamide, and butyrate. Discovering additional small molecules that regulate its expression will identify new molecular mechanisms involved in CAMP regulation and increase understanding of how diet and nutrition can improve immune function.

METHODS AND RESULTS

We discovered that two stilbenoids, resveratrol and pterostilbene, induced CAMP promoter-luciferase expression. Synergistic activation was observed when either stilbenoid was combined with 1α,25(OH)2 D3. Both stilbenoids increased CAMP mRNA and protein levels in the monocyte cell line U937 and synergy was observed in both U937 and the keratinocyte cell line, HaCaT. Inhibition of resveratrol targets sirtuin-1, cyclic AMP production and the c-Jun N-terminal, phosphoinositide 3 and AMP-activated kinases did not block induction of CAMP by resveratrol or synergy with 1α,25(OH)2 D3. Nevertheless, inhibition of the extracellular signal regulated 1/2 and p38 mitogen-activated protein kinases, increased CAMP gene expression in combination with 1α,25(OH)2 D3 suggesting that inhibition of these kinases by resveratrol may explain, in part, its synergy with vitamin D.

CONCLUSION

Our findings demonstrate for the first time that stilbenoid compounds may have the potential to boost the innate immune response by increasing CAMP gene expression, particularly in combination with 1α,25(OH)2 D3.

The effects of age on CD4+ T cell TLR-2 expression and TLR-2 mediated direct co-stimulation (122.6)

Background: Functional Toll like receptors (TLR) are found on human T cells. Neonatal antigen presenting cells (APC) have altered responses to TLR ligands; it is unknown if neonatal CD4+ T cell TLR responses are comparable to adult. Objective: Comparison of TLR-2 expression and responsiveness to TLR-2 direct co-stimulation among total and naïve CD4+ T cell subsets from neonates and adults. Methods: T cell subsets (CD3+CD4+ or CD3+CD4+CD45RA+) were isolated from cord and adult peripheral blood mononuclear cells by flow sorting ( >99.5% purity) and cultured in an APC-free model with α-CD3 ± α -CD28 ± TLR-2 ligand Pam3CYS4. Quantitative PCR and ELISA determined TLR-2 expression and cytokine production. Results: Neonatal CD4+ T cells are predominately naïve (97.2% CD45RA+) but express 5-fold more TLR-2 mRNA than adult CD4+ T cells. Pam3CYS4 provides direct co-stimulation in the presence of α-CD3 to adult and neonatal total CD4+ T cells resulting in IL-2, TNF-α, and IFN-γ production; provision of additional co-stimulation (α-CD28) further enhances cytokine production. When comparing total CD4+ T cell populations, neonatal cells generate significantly less cytokines than adult. When naïve neonatal and adult T cells are compared, neonatal cells generate more cytokines in response to TLR-2 mediated co-stimulation. Conclusions: Naïve neonatal CD4+ T cells have enhanced TLR-2 expression and increased sensitivity to direct TLR-2 co-stimulation as compared to naïve adult cells.

Light echoes reveal an unexpectedly cool η Carinae during its nineteenth-century Great Eruption

η Carinae is one of the most massive binary stars in the Milky Way. It became the second-brightest star in our sky during its mid-nineteenth-century 'Great Eruption', but then faded from view (with only naked-eye estimates of brightness). Its eruption is unique in that it exceeded the Eddington luminosity limit for ten years. Because it is only 2.3 kiloparsecs away, spatially resolved studies of the nebula have constrained the ejected mass and velocity, indicating that during its nineteenth-century eruption, η Car ejected more than ten solar masses in an event that released ten per cent of the energy of a typical core-collapse supernova, without destroying the star. Here we report observations of light echoes of η Carinae from the 1838-1858 Great Eruption. Spectra of these light echoes show only absorption lines, which are blueshifted by -210 km s(-1), in good agreement with predicted expansion speeds. The light-echo spectra correlate best with those of G2-to-G5 supergiants, which have effective temperatures of around 5,000 kelvin. In contrast to the class of extragalactic outbursts assumed to be analogues of the Great Eruption of η Carinae, the effective temperature of its outburst is significantly lower than that allowed by standard opaque wind models. This indicates that other physical mechanisms such as an energetic blast wave may have triggered and influenced the eruption.

Effects of vitamin D insufficiency on bone mineral density in African American men

In African American men serum, 25-hydroxyvitamin D (25-OHD) was below 30 ng/ml in 89% of subjects. In overall group, there was no correlation between 25-OHD and bone mineral density (BMD). A subgroup analysis of subjects with 25-OHD <or=15 ng/ml showed that serum 25-OHD was positively associated with BMD.

INTRODUCTION

This study examined the effects of low serum 25-hydroxyvitamin D (25-OHD) on bone mineral density (BMD) in African American (AA) men from the general medicine clinic at an inner city Veteran Administration medical center.

METHODS

The data for 112 AA males who had both 25-OHD levels and BMD of spine and hip were extracted and analyzed using SAS software.

RESULTS

AA men were aged 38 to 85 years, with mean age of 62 years. Levels of 25-OHD ranged from 4 to 45 ng/ml, with mean 17.5 ng/ml, 24% and 89% of the subjects had 25-OHD below 10 and 30 ng/ml, respectively. In the overall group, there was no correlation between 25-OHD and BMD at any site. In a subgroup analysis of subjects with 25-OHD <or=15 ng/ml, in multiple adjusted models, 25-OHD was positively associated with BMD of spine (r = 0.26, p = 0.05), total hip (r = 0.27, p < 0.05), ward's triangle (r = 0.25, p = 0.05), and trochanter (r = 0.30, p < 0.05).

CONCLUSIONS

The negative effect of vitamin D insufficiency on bone was observed only at very low levels of 25-OHD, suggesting that AA male skeleton is relatively resistant to the effects of secondary hyperparathyroidism.

Coronary calcification and osteoporosis in men and postmenopausal women are independent processes associated with aging

The objective of this study was to investigate whether low bone mass is directly associated with the severity of coronary atherosclerosis in men and postmenopausal women self-referred for evaluation of coronary atherosclerosis and osteoporosis. Low bone mass was evaluated by measurement of bone mineral density (BMD) using quantitative computerized tomography (QCT). Coronary atherosclerosis was evaluated by measurement of coronary calcium (CC) burden using electron beam computerized tomography (EBCT). Using a cross-sectional design, we tested the hypothesis that osteoporosis and coronary atherosclerosis are correlated, age-dependent processes. Study variables were BMD, CC scores, and other known risk factors for osteoporosis and atherosclerosis. Qualifying for the study were 313 postmenopausal women and 167 men. Men had higher baseline CC scores and higher body mass indexes compared to women. In females, those patients with coronary calcification were older and had significantly lower BMD compared to those without calcification. In males, those patients with coronary calcification were older. By univariate correlation analysis, the degree of coronary calcification was inversely associated with BMD in postmenopausal women (P < 0.0001) but not in men. However, after controlling for age, this association was absent for both men and postmenopausal women. Using multivariate logistic regression analysis in women and men separately, age was the only significant predictor of positive CC status and low BMD. Our study suggests that in postmenopausal women and in men, after controlling for age, osteoporosis and coronary atherosclerosis are independent processes.

Utility of screening tools for the prediction of low bone mass in African American men

INTRODUCTION

Osteoporosis remains under-diagnosed, particularly in African American men, despite the availability of reliable diagnostic tests. In women, several screening tools, including heel ultrasound and clinical assessment tools, reliably predict low bone mass, however the usefulness of these screening tools in African American men is unknown. The aim of this study was to determine the utility of screening tools, namely heel ultrasound, the osteoporosis self-assessment tool (OST), weight-based criterion (WBC) and body mass index (BMI), in screening for low bone mass in African American men.

MATERIALS AND METHODS

African American men 35 years of age and older were invited to participate. The OST risk index is a score based on age and weight [(weight in kilograms--age in years)x0.2]. Bone mineral density (BMD) of the heel was measured by heel ultrasound, and BMD of both the lumbar spine and hip were determined by dual energy X-ray absorptometry (DXA). One hundred and twenty-eight men fulfilled the inclusion criteria for our study.

RESULTS

The population prevalence of osteopenia and osteoporosis were 39% and 7%, respectively. Using a heel ultrasound T-score cut-off value of -1 or less, we predicted low bone mass (T-score of -2 or less at the hip) with a sensitivity of 83%, a specificity of 71% and an area under the curve (AUC) of 0.80. Using an OST cut-off value of 4, we predicted low bone mass with a sensitivity of 83%, a specificity of 57% and an AUC of 0.83. The OST risk index ranged from 18.1 to -6.1, based on which we categorized risk as: low, 5 or greater; moderate, 0-4; high, -1 or less. Of the men with a high-risk OST score, 87% had either osteopenia or osteoporosis based on World Health Organization (WHO) criteria. Using the WBC alone with a cut-off value of 85 kg, we predicted low bone mass with a sensitivity of 74%, a specificity of 50% and an AUC of 0.70. A BMI cut-off value of 30 or greater yielded a sensitivity of 83%, a specificity of 43% and an AUC of 0.70 for the diagnosis of low bone mass.

DISCUSSION

The prevalence of osteopenia and osteoporosis were unexpectedly high in outpatient African American male veterans, who are considered to be at low risk for low bone mass. Heel ultrasound was able to predict low bone mass with sufficiently high sensitivity and specificity for use as a screening tool. Surprisingly, WBC and BMI proved ineffective in predicting low bone mass with adequate sensitivity and specificity. The OST, a clinical formula based on weight and age, appeared to be an easy and reliable screening tool for identifying men at high risk for low bone mass.

Effects of changes in pH and CO2 on pulmonary arterial wall tension are not endothelium dependent

We examined the changes in isolated pulmonary artery (PA) wall tension on switching from control conditions (pH 7.38 +/- 0.01, PCO2 32.9 +/- 0.4 Torr) to isohydric hypercapnia (pH change 0.00 +/- 0.01, PCO2 change 24.9 +/- 1.1 Torr) or normocapnic acidosis (pH change -0.28 +/- 0.01, PCO2 change -0.3 +/- 0.04 Torr) and the role of the endothelium in these responses. In rat PA, submaximally contracted with phenylephrine, isohydric hypercapnia did not cause a significant change in mean (+/- SE) tension [3.0 +/- 1.8% maximal phenylephrine-induced tension (Po)]. Endothelial removal did not alter this response. In aortic preparations, isohydric hypercapnia caused significant (P < 0.01) relaxation (-27.4 +/- 3.2% Po), which was largely endothelium dependent. Normocapnic acidosis caused relaxation of PA (-20.2 +/- 2.6% Po), which was less (P < 0.01) than that observed in aortic preparations (-35.7 +/- 3.4% Po). Endothelial removal left the pulmonary response unchanged while increasing (P < 0.01) the aortic relaxation (-53.1 +/- 4.4% Po). These data show that isohydric hypercapnia does not alter PA tone. Reduction of PA tone in normocapnic acidosis is endothelium independent and substantially less than that of systemic vessels.

Molecular recognition of a Salmonella trisaccharide epitope by monoclonal antibody Se155-4

The binding site of monoclonal antibody Se155-4, which has been the object of successful crystallographic and antibody-engineering studies, is shown by solid-phase immunoassays to be complementary to a branched trisaccharide, alpha-D-Galp(1-->2) [alpha-D-Abep(1-->3)]-alpha-D-Manp(1, rather than to the tetrasaccharide repeating unit alpha-D-Galp(1-->2) [alpha-D-Abep(1-->3)]-alpha-D-Manp(1-->4) alpha-L-Rhap(1- of the bacterial antigen. Specificity for the 3,6-dideoxy-D-xylo-hexose (3,6-dideoxy-D-galactose) epitope present in Salmonella paratyphi B O-antigens was ensured by screening hybridoma experiments with glycoconjugates derived from synthetic oligosaccharides. Detailed epitope mapping of the molecular recognition by modified and monodeoxy oligosaccharide derivatives showed that complementary surfaces and three antibody-saccharide hydrogen bonds are essential for full binding activity. Both hydroxyl groups of the 3,6-dideoxy-D-galactose residue were obligatory for binding and consistent with the directional nature of their involvement in carbohydrate-protein hydrogen bonds; related tetrasaccharides built from the isomeric 3,6-dideoxyhexoses, 3,6-dideoxy-D-glucose, paratose, and 3,6-dideoxy-D-mannose, tyvelose were not bound by the antibody. Titration microcalorimetry measurements were consistent with the hydrogen-bonding map inferred from the crystal structure and suggest that the displacement of water molecules from the binding site accounts for the favorable entropy that accompanies binding of the native trisaccharide determinant. The protein sequences determined for the antibody VL and VH domains reveal somatic mutation of the VL germ line gene, implying that this antibody-binding site results from a mature antibody response.

Preliminary crystallographic analysis of a Fab specific for the O-antigen of Shigella flexneri cell surface lipopolysaccharide with and without bound saccharides

The Fab of a monoclonal anti-carbohydrate antibody, SYA/J6 (IgG3, kappa, murine), raised against the O-polysaccharide antigen of the cell surface lipopolysaccharide of variant Y Shigella flexneri, a Gram negative bacterium, has been crystallized in the unliganded form and in complex with tri- and pentasaccharide antigens. The three crystal forms belong to the tetragonal space group P4(3)2(1)2, or P4(1)2(1)2, with very similar unit cell dimensions and an asymmetric unit that contains one molecule of about 50,000 Daltons, and a fourth crystal form belongs to monoclinic space group P2(1) that contains four molecules of Fab in an asymmetric unit. Whereas diffractions of these crystals on an area detector-rotating anode system extend to only about 3.5 A resolution, those measured using an imaging plate and synchrotron radiation at the Photon Factory facility extend to 2.5 A.

Probing the combining site of an anti-carbohydrate antibody by saturation-mutagenesis: role of the heavy-chain CDR3 residues

The carbohydrate-binding site in Fab fragments of an antibody specific for Salmonella serogroup B O-polysaccharide has been probed by site-directed mutagenesis using an Escherichia coli expression system. Of the six hypervariable loops, the CDR3 of the heavy chain was selected for exhaustive study because of its significant contribution to binding-site topography. A total of 90 mutants were produced and screened by an affinity electrophoresis/Western blotting method. Those of particular interest were further characterized by enzyme immunoassay, and on this basis seven of the mutant Fabs were selected for thermodynamic characterization by titration microcalorimetry. With regard to residues that hydrogen bond to ligand through backbone interactions, Gly102H could not be substituted, while several side chains could be introduced at Gly100H and Tyr103H with relatively little effect on antigen binding. There was, however, a preference for nonpolar side chains at position 103H. Substitution of His101H with carboxylate and amide side chains gave mutants with binding affinities approaching that of the wild type; complete side-chain removal by mutation to Gly was tolerated with a 10-fold reduction in binding constant. Analysis of binding by titration microcalorimetry revealed some dramatic thermodynamic changes hidden by the similarity of the binding constants. Similar effects were observed with residue changes in an Arg-Asp salt-bridge at the base of the loop. These results indicate that alterations to higher affinity anti-carbohydrate antibodies are characterized by an enthalpy-entropy compensation factor which allows for fundamental changes in the nature of the binding interactions but impedes engineering for increases in affinity.

Preliminary crystal structure analysis of an Fab specific for a Salmonella O-polysaccharide antigen

The Fab from an IgG1, lambda murine monoclonal antibody with specificity for the O-polysaccharide antigen of Salmonella typhimurium has been crystallized in the absence and presence of hapten. The conditions for crystal growth were vapor diffusion equilibration with 16 to 23% polyethylene glycol 8000 solutions. Data have been collected from crystals of the complex in space group P212121, a = 60.6 A, b = 111.3 A, c = 61.1 A, and refinement of a molecular replacement solution is underway.

Synthesis and expression in Escherichia coli of DNA encoding the murine lambda 1 chain of a monoclonal antibody specific for Salmonella serotype B O-antigen

A 658 bp DNA sequence corresponding to the murine lambda 1 chain of a monoclonal antibody, Se155-4, specific for the Salmonella serotype B O-antigen, was designed using Escherichia coli preferred codons and chemically synthesized by ligation of synthetic fragments into a linearized plasmid followed by transformation into E. coli. A synthetic signal peptide (ompA) was fused to express the L chain as a free polypeptide into the periplasm of E. coli cells. After isolation and purification, heterologous recombination of the E. coli L chain with mouse H chain gave an active antigen-binding protein. The activity was 15-20% when compared to protein created by an equivalent association of isolated natural mouse L and H chains as measured by a direct EIA assay. In inhibition experiments with the polysaccharide antigen, the two proteins showed identical titration curves and 50% inhibition points, indicating comparable KA values.