The Romano-Ward syndrome--1964-2014: 50 years of progress.

This year marks the 50th anniversary of publication in the then Journal of the Irish Medical Association of the seminal work by Irish paediatrician Professor Conor Ward entitled 'A new familial Cardiac Syndrome in Children'. The condition soon became known by the eponym Romano-Ward Syndrome and is now recognised as the congenital Long QT Syndrome. Here we review the major developments in the field over the past fifty years, with special mention of the important contributions made by Irish researches.

Comparative virulence of Beauveria bassiana isolates against lepidopteran pests of vegetable crops.

Forty-three isolates of the entomopathogenic fungus Beauveria bassiana were screened for virulence against second-instar larvae of diamondback moth (Plutella xylostella) (DBM), European corn borer (Ostrinia nubilalis) (ECB), corn earworm (Helicoverpa zea) (CEW), and fall armyworm (Spodoptera frugiperda) (FAW); 30 of these isolates were tested against beet armyworm (Spodoptera exigua) (BAW). Highly virulent isolates were also tested against black cutworm (Agrotis ipsilon) (BCW), and the most virulent isolate was also assayed against imported cabbage worm (Pieris rapae) (ICW) and cabbage looper (Trichoplusia ni) (CL). All lepidopteran species tested were susceptible to B. bassiana. Corn earworm and beet armyworm were most susceptible to fungal infection, and fall armyworm was least susceptible. Limited testing suggested low susceptibility of black cutworm and cabbage looper. B. bassiana isolate 1200 exhibited virulence against all pest species greater than or equal to commercial strain GHA of B. bassiana currently registered in the USA as BotaniGard. In assays in which larvae were topically sprayed and maintained on the treated substrate for 24h at 100% relative humidity, 6-day (25 degrees C) median lethal concentrations (LC(50)s) of this isolate against CEW, BAW, DBM, FAW, ICW, ECB, CL, and BCW were 4, 5, 7, 11, 12, 98, 125, and 273 conidia/mm(2), respectively. The respective LC(50)s of commercial strain GHA against these pest species were 9, 67, 97, 1213, 29, 1668, 541, and 3504 conidia/mm(2). Use of LC(50) versus median lethal concentration ratios (comparing LC(50)s of each isolate to a "standard" strain) generated similar rankings of isolate virulence. Results from parametric ANOVAs of log LC(50) values followed by Tukey HSD multiple comparisons tests and those from Kruskal-Wallis nonparametric analyses followed by sequential Bonferroni tests for means comparisons were nearly identical.

Clustering hypothesis of some high-temperature superconductors.

Cluster formation in metallic crystal lattices is important for most high-temperature superconductors.

T-wave morphology can distinguish healthy controls from LQTS patients.

Long QT syndrome (LQTS) is an inherited disorder associated with prolongation of the QT/QTc interval on the surface electrocardiogram (ECG) and a markedly increased risk of sudden cardiac death due to cardiac arrhythmias. Up to 25% of genotype-positive LQTS patients have QT/QTc intervals in the normal range. These patients are, however, still at increased risk of life-threatening events compared to their genotype-negative siblings. Previous studies have shown that analysis of T-wave morphology may enhance discrimination between control and LQTS patients. In this study we tested the hypothesis that automated analysis of T-wave morphology from Holter ECG recordings could distinguish between control and LQTS patients with QTc values in the range 400-450 ms. Holter ECGs were obtained from the Telemetric and Holter ECG Warehouse (THEW) database. Frequency binned averaged ECG waveforms were obtained and extracted T-waves were fitted with a combination of 3 sigmoid functions (upslope, downslope and switch) or two 9th order polynomial functions (upslope and downslope). Neural network classifiers, based on parameters obtained from the sigmoid or polynomial fits to the 1 Hz and 1.3 Hz ECG waveforms, were able to achieve up to 92% discrimination between control and LQTS patients and 88% discrimination between LQTS1 and LQTS2 patients. When we analysed a subgroup of subjects with normal QT intervals (400-450 ms, 67 controls and 61 LQTS), T-wave morphology based parameters enabled 90% discrimination between control and LQTS patients, compared to only 71% when the groups were classified based on QTc alone. In summary, our Holter ECG analysis algorithms demonstrate the feasibility of using automated analysis of T-wave morphology to distinguish LQTS patients, even those with normal QTc, from healthy controls.

The assimilation of tri- and tetrapeptides by human erythrocytes.

Evidence is presented that tripeptides enter human erythrocytes via saturable transport system(s) at rates similar to those previously described for dipeptides (King, G.F. and Kuchel, P.W. (1985) Biochem. J. 227, 833-842) but that the transmembrane flux rates for tetrapeptides are considerably less. 1H spin-echo NMR spectroscopy was used to monitor the coupled uptake and hydrolysis of peptides by red cells, since it enabled the simultaneous measurement of the levels of substrates and products of peptidase-catalysed reactions in suspensions with haematocrits similar to those found in vivo. Weighted non-linear least-squares regression of the integrated Michaelis-Menten equation onto progress curves obtained from the hydrolysis of Tyr-Gly-Gly and Gly-Gly-Gly in RBC lysates gave Km = 2.11 +/- 0.08 and 23.4 +/- 0.9 mmol/l and Vmax = 307 +/- 3 and 905 +/- 22 mmol/h per 1 packed cells, respectively. In whole cell suspensions, the rate of hydrolysis was considerably less and was dominated by the transmembrane flux of tripeptide. Progress curve analysis thus yielded the steady-state kinetic parameters for peptide transport; the values were Km = 11.6 +/- 1.1 and 56 +/- 18 mmol/l and Vmax = 12.9 +/- 3.0 and 36.4 +/- 3.2 mmol/h per 1 packed cells, respectively, for the previously mentioned peptides. The rate of transport of the tetrapeptide Gly-Gly-Gly-Gly was considerably less than either of the tripeptides. The above mentioned steady-state kinetic parameters were used in computer simulations of the coupled uptake and hydrolysis of tripeptides by human erythrocytes under physiological conditions; these simulations revealed certain similarities between the rates of peptide uptake by erythrocytes and the intestine in vivo.

HERG K+ channels: friend and foe.

The K+ channel encoded by the human ether-à-go-go related gene (HERG) is one of many ion channels that are crucial for normal action potential repolarization in cardiac myocytes. HERG encodes the pore-forming subunit of the rapid component of the delayed rectifier K+ channel, I(K(Vr)). HERG K+ channels are of considerable pharmaceutical interest as possible therapeutic targets for anti-arrhythmic agents and as the molecular target responsible for the cardiac toxicity of a wide range of pharmaceutical agents. Recent studies of the molecular basis of the promiscuity of HERG K+ channel drug binding has not only started to shed light on this tricky pharmaceutical problem but has also provided further insights into the structure and function of HERG K+ channels.

Swelling-activated and isoprenaline-activated chloride currents in guinea pig cardiac myocytes have distinct electrophysiology and pharmacology.

We have used the whole-cell patch clamp recording technique to characterize a swelling-activated chloride current in guinea pig atrial and ventricular myocytes and to compare the electrophysiological and pharmacological properties of this current with the isoprenaline-activated chloride current in the same cell types. Osmotic swelling of guinea pig cardiac myocytes caused activation of an outwardly rectifying, anion-selective current with a conductance and permeability sequence of I- approximately NO3- > Br- > Cl- > Asp-. This current was inhibited by tamoxifen, 4,4'-diisothiocyano-stilbene-2,2'-disulphonate and anthracene-9-carboxylic acid, in decreasing order of potency. The isoprenaline-activated anion current, like the swelling-activated current, had a higher permeability to I- relative to Cl-, but it had a markedly reduced conductance for I- compared to Cl-. The isoprenaline-activated current was insensitive to inhibition by tamoxifen, 4,4'-diisothiocyanostilbene-2,2'-disulphonate and anthracene-9-carboxylic acid. The swelling-activated current could be elicited in > 90% atrial myocytes studied but only 34% ventricular myocytes. Conversely, the isoprenaline-activated current was elicited in < 10% atrial myocytes and > 90% ventricular myocytes. In those ventricular myocytes where it was possible to elicit swelling-activated and isoprenaline-activated currents simultaneously, the currents retained the same distinguishing characteristics as when they were elicited in isolation. Thus, while guinea pig atrial cells appear to preferentially express swelling-activated chloride channels and guinea pig ventricular myocytes preferentially express isoprenaline-activated chloride channels, the presence of these two channel types are not necessarily mutually exclusive. This raises the possibility that there may be coordinated regulation of the expression of different Cl- channels within the heart.

Cell swelling has differential effects on the rapid and slow components of delayed rectifier potassium current in guinea pig cardiac myocytes.

Cell swelling has been shown to cause activation of a variety of cardiac sarcolemmal ionic conductances including potassium channels. The aim of this study was to investigate the effect of swelling on the two subtypes of delayed rectifier potassium current (IKr and IKs) in single guinea pig myocytes using the whole-cell configuration of the patch clamp technique. When the holding potential was set at -40 mV and stepped to +40 mV for 1 s under isoosmotic conditions (300 mOsm) a delayed rectifier current (IK) was activated (0.86 +/- 0.05 nA; n = 43). Switching to a hypoosmotic solution (200 mOsm) caused a rapid increase in IK to a mean value of 1.43 +/- 0.10 nA (p < 0.05; n = 43). The effect of swelling on the two subtypes of IK was studied by analysis of deactivating tail currents using an envelope of tails protocol (stepping from -40 to +40 mV for 18 different pulse durations between 50 ms and 2.9 s; n = 16). Swelling caused a decrease in current amplitude measured at the end of the pulse (and IKtail) at short durations (< or = 150 ms) however, when the pulse duration was > 1 s swelling caused a significant increase in current. Using a pulse protocol to measure IKr with minimal contamination by IKs (voltage step from -40 to -10 mV for 250 ms) a 50-100 pA current was elicited which could be completely blocked by dofetilide (0.2 microM; n = 3). Introduction of hypoosmotic solution caused a significant decrease in IKr and when dofetilide (0.2 or 1.0 microM) was introduced the current remaining was decreased further (p < 0.05; n = 5), but was not completely blocked, thus suggesting that swelling had decreased the ability of dofetilide to block IKr. Similar results were obtained over a range of dofetilide concentrations and with a second IKr blocker, La3+. In Ca(2+)-free external solutions, pulsing to -10 mV for 500 ms to measure IKr in the absence of IKs, and to +60 mV for 5 s (with 0.2 microM dofetilide) to evoke only IKs, it was clear that swelling significantly increased IKs (pulse and tail currents) and decreased IKr. In addition, when measured using the perforated patch method, swelling modulated IKt and IKs in a similar fashion. We conclude that swelling has differential effects on the subtypes of the classical cardiac IK, which may have important implications in our understanding of the mechanisms underlying ischaemia- and reperfusion-induced arrhythmogenesis.

Developmental regulation of the gradient of cftr expression in the rabbit heart.

Gradients of ion channels across the left ventricular free wall of the heart have been found for a number of repolarizing ion channels. Amongst these are the cAMP-activated chloride channels encoded by cftr. In this report, we show that the epicardial (higher) to endocardial (lower) gradient of cftr mRNA found in adult rabbit hearts is not present in embryonic hearts. The gradient starts to develop shortly after birth, and over a period of 5-6 weeks increases to the levels found in the adult. This is the first report of the developmental regulation of any cardiac ion channel mRNA gradient.

Action potential shortening through the putative beta4-adrenoceptor in ferret ventricle: comparison with beta1- and beta2-adrenoceptor-mediated effects.

The electrophysiological responses to (-)-CGP 12177 ((-)-4-(3-tertiarybutylamino-2-hydroxypropoxy) benzimidazol-2-one), an agonist for the putative beta4-adrenoceptor, were investigated on isolated perfused ferret hearts paced at 100 min(-1) and compared to those of (-)-noradrenaline and (-)-adrenaline, mediated through beta1- and beta2-adrenoceptors respectively. The three agonists decreased ventricular monophasic action potential duration but prolonged the action potential plateau; beta3-adrenoceptor-selective agonists had no effect. (-)-CGP 12177 was the most potent, but (-)-noradrenaline the most efficacious; both agonists caused ventricular extra-systoles. Because only (-)-noradrenaline but not (-)-CGP 12177 elicited shortening of the refractory period, the mechanism of arrhythmias mediated through beta1- and putative beta4-adrenoceptors may be different.

Cortisol influences the ontogeny of both alpha- and beta-subunits of the cardiac sodium channel in fetal sheep.

During development, the heart has to adapt to changes in shape, size and, at birth, to significant changes in arterial pressure. The orderly contraction of the heart is dependent on the coordinated expression of ion channels at appropriate densities in individual cardiac myocytes. The present study demonstrated that the expression of the alpha-subunit of the cardiac sodium channel, SCN5a, was high at mid gestation but then decreased until 10 days before birth before increasing again. Whereas the beta-subunit, SCN1b, gradually increased in expression towards partum, there was no detectable expression of SCN3b at any gestational time point. Fetal adrenalectomy prior to the normal prepartum surge in cortisol caused a reduction in expression of SCN1b and a 7.0 kb transcript of SCN5a, but not the major 8.5 kb transcript. Conversely, cortisol infusion into immature fetuses precociously increased expression levels of SCN1b and the SCN5a 7.0 kb transcript. The results show that cortisol regulates cardiac SCN gene expression in fetal sheep during late gestation. These findings could have implications for the aetiology of sudden infant death syndrome and for the intrauterine programming of adult cardiovascular disease.

Comparing alternative approaches to establishing regulatory levels for reproductive toxicants: DBCP as a case study.

This paper compares four alternative approaches for deriving regulatory levels for reproductive toxicants by applying them to the available data on the human spermatotoxicant 1,2-dibromo-3-chloropropane (DBCP). The alternatives examined include the Proposition 65 approach (application of a mandatory 1000-fold uncertainty factor to a no-observed-adverse-effect level [NOAEL]), the Environmental Protection Agency (EPA) approach (application of flexible uncertainty factors to a NOAEL), the Benchmark Dose approach (application of flexible uncertainty factors to a dose associated with a known level of change in a reproductive parameter), and the Quantitative Risk Estimation approach (using low-dose linear extrapolation and a model of the relationship between sperm count and infertility). Applied to DBCP, these approaches do not produce substantially different estimates of allowable exposure levels. However, the approaches do have different data requirements and provide different amounts of information on reproductive hazards to risk managers and the public. Neither the Proposition 65 nor the EPA approach provides information about the extent of health risk remaining at a regulatory level. In contrast, the Benchmark Dose approach can provide estimates of the magnitude of sperm count reduction at a regulatory level, and the Quantitative Risk Estimation approach can provide estimates of exposure-induced infertility.

Yellow fever vaccination and pregnancy: a four-year prospective study.

During an outbreak of yellow fever (YF) in Nigeria in 1986-1987, women at various stages of pregnancy were vaccinated against YF, either because those pregnancies were not known at the time or because they requested vaccination out of fear of acquiring the disease. This offered an opportunity to assess the safety and efficacy of YF vaccine in pregnant women and the effect of this vaccine on their newborn children. Pre-vaccination and post-vaccination serum samples from the vaccinated pregnant women were tested by enzyme-linked immunosorbent assay and by neutralization tests for antibody to YF virus. The results showed that the antibody responses of these pregnant women were much lower than those of YF-vaccinated, non-pregnant women in a comparable control group. Follow-up of these women and their newborn children for 3-4 years showed no abnormal effect that could be attributed to the YF vaccine, which suggests that vaccination of pregnant women, particularly during a YF epidemic, may not be contraindicated.

Risk assessment and research: an essential link.

Regulatory agencies, such as the U.S. Environmental Protection Agency, use health risk assessment information in developing pollution control regulations and for setting regulatory and research priorities. The risk assessment process, however, is hampered by limitations in test methods, in models for exposure and dose-response, and by chemical-specific data gaps. The research/risk assessment/risk management framework provides opportunities for targeting and coordinating research to address these limitations. Enhanced communication among researchers, risk assessors and risk managers to foster better development and use of scientific information in decision making, and incentives for interdisciplinary research efforts, are needed.

Childhood respiratory symptoms, hospital admissions, and long-term exposure to airborne particulate matter.

The effects of long-term exposure to air pollution on respiratory symptoms and respiratory hospitalization (for asthma, bronchitis or pneumonia) were assessed in a cross-sectional study of children (ages 7--11 years, N=667) living in a moderately industrialized city in Central Slovakia. Individual health, residence and family history data obtained through the CESAR study were coupled, using Geographic Information System (GIS) technologies, with total suspended particulate (TSP) exposure estimates derived from dispersion modeling of almost all local stationary sources. These data were used to assess, at the intra-city level and child-specific level, the potential for TSP as a risk factor for respiratory disease in children. TSP, PM10, and PM2.5 monitored ambient concentrations are highly correlated in the study location. Modeled TSP concentrations resulting from local source emissions are dominated by a large wood processing facility, suggesting variation in exposures among children. The prevalence of respiratory non-asthmatic symptoms and hospitalizations was associated with increased TSP. No association between long-term exposure to TSP and asthma diagnosis or wheeze symptoms was found. Logistic regression modeling indicated a significant increase in hospital admissions for asthma, bronchitis or pneumonia associated with increasing air pollution (OR 2.16, CI, 1.01--4.60), doctor-diagnosed bronchitis (OR 1.53, CI, 1.02-2.30), and parent-reported chronic phlegm (OR 3.43, CI, 1.64--7.16), expressed as odds for a 15 microg/m3 increase in estimated TSP exposure, and these increases are not due to differences in socio-economic, health care or other identified factors.

Personal exposure to particles in Banská Bystrica, Slovakia.

Epidemiological studies have associated adverse health impacts with ambient concentrations of particulate matter (PM), though these studies have been limited in their characterization of personal exposure to PM. An exposure study of healthy nonsmoking adults and children was conducted in Banska Bystrica, Slovakia, to characterize the range of personal exposures to air pollutants and to determine the influence of occupation, season, residence location, and outdoor and indoor concentrations on personal exposures. Twenty-four-hour personal, at-home indoor, and ambient measurements of PM10, PM2.5, sulfate (SO4(2-)) and nicotine were obtained for 18 office workers, 16 industrial workers, and 15 high school students in winter and summer. Results showed that outdoor levels of pollutants were modest, with clear seasonal differences: outdoor PM10 summer/winter mean = 35/45 microg/m3; PM2.5 summer/winter mean = 22/32 microg/m3. SO4(2-) levels were low (4-7 microg/m3) and relatively uniform across the different sample types (personal, indoor, outdoor), areas, and occupational groups. This suggests that SO4(2-) may be a useful marker for combustion mode particles of ambient origin, although the relationship between personal exposures and ambient SO4(2-) levels was more complex than observed in North American settings. During winter especially, the central city area showed higher concentrations than the suburban location for outdoor, personal, and indoor measures of PM10, PM2.5, and to a lesser extent for SO4(2-), suggesting the importance of local sources. For PM2.5 and PM10, ratios consistent with expectations were found among exposure indices for all three subject groups (personal>indoor>outdoor), and between work type (industrial>students>office workers). The ratio of PM2.5 personal to indoor exposures ranged from 1.0 to 3.9 and of personal to outdoor exposures from 1.6 to 4.2. The ratio of PM10 personal to indoor exposures ranged from 1.1 to 2.9 and the ratio of personal to outdoor exposures from 2.1 to 4.1. For a combined group of office workers and students, personal PM10/PM2.5 levels were predicted by statistically significant multivariate models incorporating indoor (for PM2.5) or outdoor (for PM10) PM levels, and nicotine exposure (for PM10). Small but significant fractions of the overall variability, 15% for PM2.5 and 17% for PM10, were explained by these models. The results indicate that central site monitors underpredict actual human exposures to PM2.5 and PM10. Personal exposure to SO4(2-) was found to be predicted by outdoor or indoor SO4(2-) levels with 23-71% of the overall variability explained by these predictors. We conclude that personal exposure measurements and additional demographic and daily activity data are crucial for accurate evaluation of exposure to particles in this setting.

Large-diameter suction system reduces oropharyngeal evacuation time.

Aspiration of vomitus is associated with significant morbidity and mortality. Standard suction equipment may be incapable of rapidly evacuating vomitus from the oropharynx. In this prospective, randomized, controlled bench trial, we compared a large-diameter suction system (5/8-inch open-bore suction tip and 3/4-inch tubing attached to a 1-inch pour spout) with two standard suction systems (small-diameter blunt-nosed and medium-diameter open-bore 1/4-inch suction tips connected to 1/4-inch tubing). Mean evacuation times from the mouth of a volunteer of 90 mL of water, activated charcoal, and Progresso vegetable soup were measured. All systems removed water within 3 s. With vegetable soup, however, both standard suction systems obstructed. Despite additional mechanical scooping with the standard suction wands, the large-diameter system significantly outperformed both standard systems, by 10 s with the soup and 40 s with the charcoal The reduction in oropharyngeal evacuation times of viscous and particulate material may have important clinical implications in the emergency management of the threatened airway.

Comparison of PBTK model and biomarker based estimates of the internal dosimetry of acrylamide.

Estimates of internal dosimetry for acrylamide (AA, 2-propenamide; CASRN: 79-06-1) and its active metabolite glycidamide (GA) were compared using either biomarkers of internal exposure (hemoglobin adduct levels in rats and humans) or a PBTK model (Sweeney et al., 2010). The resulting impact on the human equivalent dose (HED, oral exposures), the human equivalent concentration (HEC, inhalation), and final reference values was also evaluated. Both approaches yielded similar AA HEDs and HECs for the most sensitive noncancer effect of neurotoxicity, identical oral reference doses (RfD) of 2×10(-3) mg AA/kg bw/d, and nearly identical inhalation reference concentrations (RfC=0.006 mg/m(3) and 0.007 mg/m(3), biomarker and PBTK results, respectively). HED and HEC values for carcinogenic potential were very similar, resulting in identical inhalation unit risks of 0.1/(mg AA/m(3)), and nearly identical oral cancer slope factors (0.4 and 0.5/mg AA/kg bw/d), biomarker and PBTK results, respectively. The concordance in estimated HEDs, HECs, and reference values from these two diverse methods increases confidence in those values. Advantages and specific application of each approach are discussed. (Note: Reference values derived with the PBPK model were part of this research, and do not replace values currently posted on IRIS: http://www.epa.gov/iris/toxreviews/0286tr.pdf.).

Modeling Agrilus planipennis (Coleoptera: Buprestidae) within-tree colonization patterns and development of a subsampling technique.

Emerald ash borer, Agrilus planipennis Fairmaire, an insect native to central Asia, was first detected in southeast Michigan in 2002, and has since killed millions of ash trees (Fraxinus spp.) in North America. The objectives of this study were to 1) determine an optimal sampling location on girdled ash trap trees for detection of A. planipennis larvae based on measurements of tree characteristics, and 2) develop a whole-tree estimation method for extrapolating larval densities from subsampled heights. We conducted sampling at 1-m increments, recording larval presence, height on tree bole, bolt diameter, and bark roughness for 58 infested ash trees. Analyzing height and diameter separately, generalized linear mixed models indicated the probability of A. planipennis detection was maximized at 17.2 cm for diameter and increased linearly as vertical height increased. There was also a positive relationship between intermediate bark roughness and A. planipennis presence. Stepwise regression indicated the optimal bolts for extrapolating whole tree larval densities were, in order of importance, at heights of 1-2 m, 4-5 m, 7-8 m, and 0-1 m. Subsampling with just one or two bolts explained 70% and 86%, respectively, of the variance in A. planipennis densities. Our results can be used by resource managers to improve efficiency of detection efforts and estimate infestations of A. planipennis.