Prevalence of individual brain and eye defects potentially related to Zika virus in pregnancy in 22 U.S. states and territories, January 2016 to June 2017

During the Centers for Disease Control and Prevention's Zika Virus Response, birth defects surveillance programs adapted to monitor birth defects potentially related to Zika virus (ZIKV) infection during pregnancy. Pregnancy outcomes occurring during January 2016 to June 2017 in 22 U.S. states and territories were used to estimate the prevalence of those brain and eye defects potentially related to ZIKV. Jurisdictions were divided into three groups: areas with widespread ZIKV transmission, areas with limited local ZIKV transmission, and areas without local ZIKV transmission. Prevalence estimates for selected brain and eye defects and microcephaly per 10,000 live births were estimated. Prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated using Poisson regression for areas with widespread and limited ZIKV transmission compared with areas without local ZIKV transmission. Defects with significantly higher prevalence in areas of widespread transmission were pooled, and PRs were calculated by quarter, comparing subsequent quarters to the first quarter (January-March 2016). Nine defects had significantly higher prevalence in areas of widespread transmission. The highest PRs were seen in intracranial calcifications (PR = 12.6, 95% CI [7.4, 21.3]), chorioretinal abnormalities (12.5 [7.1, 22.3]), brainstem abnormalities (9.3 [4.7, 18.4]), and cerebral/cortical atrophy (6.7 [4.2, 10.8]). The PR of the nine pooled defects was significantly higher in three quarters in areas with widespread transmission. The largest difference in prevalence was observed for defects consistently reported in infants with congenital ZIKV infection. Birth defects surveillance programs could consider monitoring a subset of birth defects potentially related to ZIKV in pregnancy.

Evaluating Metrics Applied to the Medical Science Liaison (MSL) Role: A Survey-Based Study of Canadian MSL Leaders

INTRODUCTION

Metrics utilized within the Medical Science Liaison (MSL) role are plentiful and traditionally quantitative. We sought to understand the current use and value of metrics applied to the MSL role, including the use of qualitative metrics.

METHODS

We developed a list of 70 MSL leaders working in Canada, spanning 29 companies. Invitations were emailed Jun 16, 2020 and the 25-question online survey was open for 3 weeks. Questions were designed to assess demographics as well as how and why metrics are applied to the MSL role. Data analyses were descriptive.

RESULTS

Responses were received from 44 leaders (63%). Of the 42 eligible, 45% had ≤ 2 years of experience as MSL leaders and 86% supported specialty care products over many phases of the product lifecycle. A majority (69%) agreed or strongly agreed that metrics are critical to understanding whether an MSL is delivering value, and 98% had used metrics in the past year. The most common reason to use metrics was 'to show value/impact of MSLs to leadership' (66%). The most frequently used metric was 'number of health-care professional (HCP) interactions', despite this being seen as having moderate value. Quantitative metrics were used more often than qualitative, although qualitative were more often highly valued.

CONCLUSION

The data collected show a lack of agreement between the frequency of use for some metrics and their value in demonstrating the contribution of an MSL. Overall, MSL leaders in our study felt qualitative metrics were a better means of showing the true impact of MSLs.

Parental occupational pesticide exposure and nonsyndromic orofacial clefts

Nonsyndromic orofacial clefts are common birth defects. Reported risks for orofacial clefts associated with parental occupational pesticide exposure are mixed. To examine the role of parental pesticide exposure in orofacial cleft development in offspring, this study compared population-based case-control data for parental occupational exposures to insecticides, herbicides, and fungicides, alone or in combinations, during maternal (1 month before through 3 months after conception) and paternal (3 months before through 3 months after conception) critical exposure periods between orofacial cleft cases and unaffected controls. Multivariable logistic regression was used to estimate odds ratios, adjusted for relevant covariables, and 95% confidence intervals for any (yes, no) and cumulative (none, low [<median exposure level in controls], high [≥median exposure level in controls]) occupational pesticide exposures and cleft lip ± cleft palate and cleft palate. Associations for cleft lip ± cleft palate tended to be near unity for maternal or paternal occupational pesticide exposures, except for low paternal exposure to any pesticide, which produced a statistically significant inverse association with this subtype. Associations for cleft palate tended to be near unity for maternal exposures and mostly positive, but non-significant, for paternal exposures; a significant positive association was observed between paternal low exposure to insecticide + herbicide + fungicide and cleft palate. Combined parental exposure produced non-significant associations near or below unity for all orofacial cleft cases combined and cleft lip ± cleft palate and positive, but non-significant, associations for cleft palate. This study observed associations mostly near unity between maternal occupational pesticide exposure and orofacial clefts. Associations for paternal occupational pesticide exposures were mostly near or below unity for cleft lip ± cleft palate, and mostly positive for cleft palate. However, due to the limitations of this study, these subtype-specific results should be interpreted cautiously. Future research examining parental occupational pesticide exposure and orofacial clefts should attempt to improve exposure assessment and increase sample size to better facilitate risk estimation.

Data on processing of Ti-25Nb-25Zr β-titanium alloys via powder metallurgy route: Methodology, microstructure and mechanical properties

The data presented in this article are related to the research article entitled “Cyclic Shear behavior of conventional and harmonic structure-designed Ti-25Nb-25Zr β-titanium alloy: Back-stress hardening and twinning inhibition” (Dirras et al., 2017) [1]. The datasheet describes the methods used to fabricate two β-titanium alloys having conventional microstructure and so-called harmonic structure (HS) design via a powder metallurgy route, namely the spark plasma sintering (SPS) route. The data show the as-processed unconsolidated powder microstructures as well as the post-SPS ones. The data illustrate the mechanical response under cyclic shear loading of consolidated alloy specimens. The data show how electron back scattering diffraction(EBSD) method is used to clearly identify induced deformation features in the case of the conventional alloy.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Hypospadias and maternal exposure to atrazine via drinking water in the National Birth Defects Prevention study

BACKGROUND

Hypospadias is a relatively common birth defect affecting the male urinary tract. It has been suggested that exposure to endocrine disrupting chemicals might increase the risk of hypospadias by interrupting normal urethral development.

METHODS

Using data from the National Birth Defects Prevention Study, a population-based case-control study, we considered the role of maternal exposure to atrazine, a widely used herbicide and potential endocrine disruptor, via drinking water in the etiology of 2nd and 3rd degree hypospadias. We used data on 343 hypospadias cases and 1,422 male controls in North Carolina, Arkansas, Iowa, and Texas from 1998-2005. Using catchment level stream and groundwater contaminant models from the US Geological Survey, we estimated atrazine concentrations in public water supplies and in private wells. We assigned case and control mothers to public water supplies based on geocoded maternal address during the critical window of exposure for hypospadias (i.e., gestational weeks 6-16). Using maternal questionnaire data about water consumption and drinking water, we estimated a surrogate for total maternal consumption of atrazine via drinking water. We then included additional maternal covariates, including age, race/ethnicity, parity, and plurality, in logistic regression analyses to consider an association between atrazine and hypospadias.

RESULTS

When controlling for maternal characteristics, any association between hypospadias and daily maternal atrazine exposure during the critical window of genitourinary development was found to be weak or null (odds ratio for atrazine in drinking water = 1. 00, 95 % CI = 0.97 to 1.03 per 0.04 μg/day increase; odds ratio for maternal consumption = 1.02, 95 % CI = 0.99 to 1.05; per 0.05 μg/day increase).

CONCLUSIONS

While the association that we observed was weak, our results suggest that additional research into a possible association between atrazine and hypospadias occurrence, using a more sensitive exposure metric, would be useful.

Bayesian Spatial-temporal Model for Cardiac Congenital Anomalies and Ambient Air Pollution Risk Assessment

We introduce a Bayesian spatial-temporal hierarchical multivariate probit regression model that identifies weeks during the first trimester of pregnancy which are impactful in terms of cardiac congenital anomaly development. The model is able to consider multiple pollutants and a multivariate cardiac anomaly grouping outcome jointly while allowing the critical windows to vary in a continuous manner across time and space. We utilize a dataset of numerical chemical model output which contains information regarding multiple species of PM_2.5. Our introduction of an innovative spatial-temporal semiparametric prior distribution for the pollution risk effects allows for greater flexibility to identify critical weeks during pregnancy which are missed when more standard models are applied. The multivariate kernel stick-breaking prior is extended to include space and time simultaneously in both the locations and the masses in order to accommodate complex data settings. Simulation study results suggest that our prior distribution has the flexibility to outperform competitor models in a number of data settings. When applied to the geo-coded Texas birth data, weeks 3, 7 and 8 of the pregnancy are identified as being impactful in terms of cardiac defect development for multiple pollutants across the spatial domain.

Spatial-temporal modeling of the association between air pollution exposure and preterm birth: identifying critical windows of exposure

Exposure to high levels of air pollution during the pregnancy is associated with increased probability of preterm birth (PTB), a major cause of infant morbidity and mortality. New statistical methodology is required to specifically determine when a particular pollutant impacts the PTB outcome, to determine the role of different pollutants, and to characterize the spatial variability in these results. We develop a new Bayesian spatial model for PTB which identifies susceptible windows throughout the pregnancy jointly for multiple pollutants (PM(2.5) , ozone) while allowing these windows to vary continuously across space and time. We geo-code vital record birth data from Texas (2002-2004) and link them with standard pollution monitoring data and a newly introduced EPA product of calibrated air pollution model output. We apply the fully spatial model to a region of 13 counties in eastern Texas consisting of highly urban as well as rural areas. Our results indicate significant signal in the first two trimesters of pregnancy with different pollutants leading to different critical windows. Introducing the spatial aspect uncovers critical windows previously unidentified when space is ignored. A proper inference procedure is introduced to correctly analyze these windows.

A method to model neuron activity

This paper presents a model to simulate the activity of excitable membrane displaying Hodgkin and Huxley (H-H)-type kinetics implemented using the general-purpose circuit analysis program PSPICE. The H-H equations are represented by electrical equivalent circuit elements and the model is validated by comparison with published theoretical and measured data. The model is very easy to use and can be inserted as a sub-circuit into PSPICE simulations of more complex neural systems.

Linking environmental hazards and birth defects data

The authors describe methods for linking birth certificate and birth defect registry data to potential environmental hazards and assess potential confounding factors. Cases of selected birth defects from the Texas Birth Defects Registry were linked to their respective birth/ fetal death records. Comparison births were randomly selected from the 1996-2000 Texas birth records. Maternal addresses were related through a geographic information system to boundaries of hazardous waste sites and point locations of industries. Approximately 89% of maternal addresses of case births and 88% of comparison births were successfully related in distance to these sites and industries. Maternal characteristics associated with living within one mile of these sites included belonging to any group besides non-Hispanic white and having lower education attainment (< 16 years) or a residence within the city limits. In linking environmental and health outcome databases, researchers should be aware of factors that may confound associations between exposure and outcomes.

Very Low-Noise ENG Amplifier System Using CMOS Technology

In this paper, we describe the design and testing of a system for recording electroneurographic signals (ENG) from a multielectrode nerve cuff (MEC). This device, which is an extension of the conventional nerve signal recording cuff, enables ENG to be classified by action potential velocity. In addition to electrical measurements, we provide preliminary in vitro data obtained from frogs that demonstrate the validity of the technique for the first time. Since typical ENG signals are extremely small, on the order of 1 1 microV, very low-noise, high-gain amplifiers are required. The ten-channel system we describe was realized in a 0.8 microm CMOS technology and detailed measured results are presented. The overall gain is 10 000 and the total input-referred root mean square (rms) noise in a bandwidth 1 Hz-5 kHZ is 291 nV. The active area is 12 mm(2) and the power consumption is 24 mW from +/-2.5 V power supplies.

Epidemiology of noncomplex left ventricular outflow tract obstruction malformations (aortic valve stenosis, coarctation of the aorta, hypoplastic left heart syndrome) in Texas, 1999-2001

BACKGROUND

The left ventricular outflow tract (LVOT) malformations aortic valve stenosis (AVS), coarctation of the aorta (CoA), and hypoplastic left heart syndrome (HLHS) contribute significantly to infant mortality due to birth defects. Previous epidemiology data showed rate differences between male and female and white and black ethnic groups. The Texas Birth Defects Registry, an active surveillance program, enables study in a large, diverse population including Hispanics.

METHODS

Records of children up to 1 year old with AVS, CoA, and HLHS born in Texas from 1999 to 2001, were collected from the registry. Those including additional heart defects or a chromosomal anomaly were excluded. Multivariate analysis included: infant sex; United States-Mexico border county residence; and maternal age, race/ethnicity, birthplace, and education.

RESULTS

There were 910 cases among 1.08 million live births, of which 499 met inclusion criteria. Multivariate modeling of all LVOT malformations combined demonstrated lower prevalence rate ratios (PRRs) for black males (0.26) and Hispanic males (0.70). Similar results were found for CoA but not AVS or HLHS. Higher PRRs were noted for increased maternal age for LVOT (1.3 for 24-34 years; 1.7 for >34 years), AVS, and HLHS, but not CoA, and higher PRRs across all diagnoses for males (LVOT PRR, 2.4) were noted. CoA PRRs were higher in border county vs. non-border county residents (PRR, 2.1). Maternal education and birthplace were not significant factors.

CONCLUSIONS

There are rate differences for males among all 3 ethnic groups. Sex and ethnic differences suggest genetic etiologies, where the ethnic differences could be used to find susceptibility loci with mapping by admixture linkage disequilibrium. Increased CoA rates along the U.S.-Mexico border suggest environmental causes that will require further monitoring.

Serum osteocalcin and CTX-MMP concentration in young exercising thoroughbred racehorses

Bone responds to exercise with changes in bone (re-)modelling, which might be monitored non-invasively with biochemical bone markers. The aim of this study was to evaluate the influence of exercise on serum osteocalcin and serum carboxy-terminal cross-linked telopeptide of type I collagen generated by matrix metalloproteinases (CTX-MMP) concentration in young racehorses. Seventy-one 2 to 4-year-old Thoroughbreds were included in this prospective infield study. Blood sampling was performed six times (i.e. six sampling cycles) during a 9-month period. Serum samples were analysed with commercial osteocalcin and CTX-MMP radioimmunoassays. Two-year-old racehorses had higher serum osteocalcin and CTX-MMP values than 3-year-old horses. Gender and training amplitude did not significantly influence serum osteocalcin and CTX-MMP values. Two-year-old horses showed an increase in osteocalcin values between cycles 2 and 3 and an increase in serum CTX-MMP values between cycles 1 and 2. Serum osteocalcin and CTX-MMP concentrations decreased between cycles 4 and 5, and 5 and 6. Three-year-old horses showed an increase in serum osteocalcin levels between cycles 3 and 4 and an increase in serum CTX-MMP concentrations between cycles 1 and 2, and 3 and 4. Serum osteocalcin levels decreased between cycles 5 and 6, whereas serum CTX-MMP levels decreased between cycles 4 and 5, and 5 and 6. Two- and three-year-old horses showed a decreased osteocalcin/CTX-MMP ratio between cycles 1 and 2. Moreover, 2-year-old horses showed an increase in the osteocalcin/CTX-MMP ratio between cycles 2 and 3. Sore shin formation did not significantly influence serum osteocalcin and CTX-MMP values. Serum osteocalcin and CTX-MMP are promising bone markers for monitoring exercise induced changes in equine bone metabolism.

Prevalence of nonsyndromic oral clefts in Texas: 1995-1999

Nonsyndromic cleft lip with/without cleft palate (NSCLP) and nonsyndromic cleft palate only (NSCPO) are common complex birth defects affecting 4,000 newborns annually. We undertook a descriptive study of oral clefts in Texas, focusing on the effect of folic acid fortification and Hispanic ethnicity on the prevalence of oral clefts as these factors have not previously been described. Data on 896 infants with NSCLP and NSCPO born between 1995 and 1999 in Texas were compared to all births in Texas during the same period. Prevalence odds ratios (POR) were calculated for maternal ethnicity, race, age, parity, public health region of residence, highest level of education, and infant gender. The effect of folic acid fortification on oral clefts was also examined. Compared with whites, adjusted POR were 0.97 (95% CI = 0.77-1.23) and 0.90 (95% CI 0.72-1.14) for NSCLP and 0.46 (95% CI = 0.30-0.72) and 0.62 (95% CI = 0.42-0.90) for NSCPO in foreign-born and US-born Hispanics, respectively. After fortification was implemented, the rate of NSCLP did not decrease. However, there was a 13% decrease in the prevalence of NSCPO (adjusted POR = 0.87, 95% CI = 0.68-1.15). Compared to whites, the rates in US-born and foreign-born Hispanic women were similar for NSCLP and much lower for NSCPO. The small reduction of 13% in NSCPO after folic acid fortification is imprecise and should be interpreted cautiously. Overall, it appears that folic acid fortification has had very little or no effect on the prevalence of oral clefts in infants born in Texas.

Random error and undercounting in birth defects surveillance data: implications for inference

BACKGROUND

There has been an ongoing debate among birth defects investigators about whether or not to publish estimates of rates of birth defects with confidence intervals to allow for comparisons of rates across regions and time. A major impediment in resolving this debate has been the lack of a framework for quantifying uncertainties in the data that can be applied uniformly to birth defects surveillance programs. This report presents an overview of random error and ascertainment bias in birth defects surveillance data, and of the implications of these errors for estimation and comparisons of birth defects rates.

METHODS

We consider when confidence intervals can be used as part of a strategy to make inference on rates, as well as ratios of or differences between two rates. Worth noting is that confidence intervals only address random error in the data. In the presence of undercounting of cases, estimation of rates and confidence intervals requires knowledge or an estimate of the extent of underascertainment. Rate estimates and confidence intervals that ignore such bias can be misleading. However, if it is reasonable to assume that the ascertainment bias is constant over time (or across regions), then it is possible to make valid comparisons of rates over time (or across regions) using ratio or difference estimators, even when lack of knowledge of the extent of undercounting makes estimating the absolute rate and its confidence interval problematic. Finally, sensitivity analyses can use confidence limits to determine the difference in ascertainment bias necessary to explain an apparent difference in rates.

CONCLUSION

Because birth defects surveillance systems have evolved in the absence of agreed upon standards to guide the process, it is difficult to determine the extent to which the variability in rates of birth defects across programs or over time is real or due to differences in surveillance methods. Efforts to develop standards for birth defects surveillance may help to minimize the variability in prevalence of birth defects due to differences in case ascertainment methods and allow for evaluations of real temporal and spatial variations in environmental effects. In the meantime, if comparisons of rates need to be made to address public health concerns, it would be prudent to conduct only such comparisons between regions or across time when the degree of case ascertainment can be assumed to be relatively constant across regions and time.

Speed of sound measurements of the third metacarpal bone in young exercising thoroughbred racehorses

The purpose of this longitudinal in-field study was to evaluate the influence of exercise, age, and gender on superficial cortical bone of the third metacarpal bone (MC III) in young Thoroughbreds by measuring speed of sound (SOS) values with an axial transmission technique (Omnisense, Sunlight Ltd, Israel). Both MC III of 75 racehorses, 2 to 4 years old, were monitored with SOS measurements in 5- to 7-week intervals during a 9- month physical exercise period. Medical data and training programs (slow gallop, canter, and high-speed work) of each horse were recorded. SOS measurements began before 2-year-old horses started high-speed training. SOS values of the dorsal aspect of MC III were significantly lower in comparison with values obtained at the lateral and the medial aspect of MC III, and SOS values were inversely correlated with measurement cycles. Significant limb-associated differences in dorsal MC III SOS values were observed at measurement cycles 2, 3, and 4. SOS values obtained at the lateral and medial aspect of MC III increased with age. SOS values obtained at the dorsal aspect of MC III, decreased with age. Mares had significantly higher SOS values at the dorsal aspect of MC III, when compared with corresponding values in stallions. In 2-year-old Thoroughbreds SOS values of the dorsal MC III were significantly different between cycles 1 and 2, between cycles 3 and 4, and between cycles 4 and 5. Three-year-old horses showed significant differences between SOS values of the dorsal MC III obtained at cycles 3 and 4. Training intensities did not significantly influence SOS values. The results indicate that young exercising Thoroughbred racehorses have age-, gender-, and measurement-cycle-dependent variations in SOS values of MC III, which probably reflect adaptive variations in superficial cortical bone properties of MC III.

Identification of Streptomyces coelicolor proteins that are differentially expressed in the presence of plant material

Streptomyces coelicolor and Lemna minor were used as a model to study the modulation of bacterial gene expression during plant-streptomycete interactions. S. coelicolor was grown in minimal medium with and without L. minor fronds. Bacterial proteomes were analyzed by two-dimensional gel electrophoresis, and a comparison of the two culture conditions resulted in identification of 31 proteins that were induced or repressed by the presence of plant material. One-half of these proteins were identified by peptide mass fingerprinting by using matrix-assisted laser desorption ionization-time of flight mass spectrometry. The induced proteins were involved in energetic metabolism (glycolysis, pentose phosphate pathway, oxidative phosphorylation), protein synthesis, degradation of amino acids, alkenes, or cellulose, tellurite resistance, and growth under general physiological or oxidative stress conditions. The repressed proteins were proteins synthesized under starvation stress conditions. These results suggest that root exudates provide additional carbon sources to the bacteria and that physiological adaptations are required for efficient bacterial growth in the presence of plants.

A synthetic aragonite-based bioceramic: influence of process parameters on porosity and compressive strength

We investigate the influence of process parameters such as weight fraction and particle size of pore-former, and isostatic pressure, on porosity and compressive strength of non-sintered porous calcium carbonate biomaterials compacted at high pressure in uniaxial or isostatic mode. Experiment design and results analysis are performed according to a two-level 2k factorial design method (FDM). Results indicate that only the weight fraction of pore-former (wt fpf) influences significantly the porosity and the compressive strength. The porosity P, is described by a linear function of wt fpf, and the compressive strength sigma(comp), by an exponential one. For materials compacted under uniaxial pressing: P (vol%) = 33.7 + 85.4 (wt fpf) and sigma(comp) (MPa) = 28.8e(-9.2(wt fpf)) with 0.1 < or = wt fpf < or = 0.3. For materials compacted in isostatic mode: P (vol%) = 33.9 + 82.1 (wt fpf) and sigma(comp) (MPa) = 24.0e(-7.0(wt fpf)) with 0.15 < or = wt fpf < or = 0.35. The pore-former particle size has no significant influence on both properties. The increase in isostatic pressure provides slightly lower porosity and better compressive strength. For a fixed fraction of pore-former, isostatic pressing leads to a better compressive strength than uniaxial pressing. This study indicates that, for a constant amount of pore former, the size of macropores can be adjusted to reach optimal bone-ingrowth without change in compressive strength.

Construction of avian adenovirus CELO recombinants in cosmids

The avian adenovirus CELO is a promising vector for gene transfer applications. In order to study this potentiality, we developed an improved method for construction of adenovirus vectors in cosmids that was used to engineer the CELO genome. For all the recombinant viruses constructed by this method, the ability to produce infectious particles and the stability of the genome were evaluated in a chicken hepatocarcinoma cell line (LMH cell line). Our aim was to develop a replication-competent vector for vaccination of chickens, so we first generated knockout point mutations into 16 of the 22 unassigned CELO open reading frames (ORFs) to determine if they were essential for virus replication. As the 16 independent mutant viruses replicated in our cellular system, we constructed CELO genomes with various deletions in the regions of these nonessential ORFs. An expression cassette coding for the enhanced green fluorescent protein (eGFP) was inserted in place of these deletions to easily follow expression of the transgene and propagation of the vector in cell monolayers. Height-distinct GFP-expressing CELO vectors were produced that were all replication competent in our system. We then retained the vector backbone with the largest deletion (i.e., 3.6 kb) for the construction of vectors carrying cDNA encoding infectious bursal disease virus proteins. These CELO vectors could be useful for vaccination in the chicken species.

Assessing exposure to disinfection by-products in women of reproductive age living in Corpus Christi, Texas, and Cobb county, Georgia: descriptive results and methods

We conducted a field study in Corpus Christi, Texas, and Cobb County, Georgia, to evaluate exposure measures for disinfection by-products, with special emphasis on trihalomethanes (THMs). Participants were mothers living in either geographic area who had given birth to healthy infants from June 1998 through May 1999. We assessed exposure by sampling blood and water and obtaining information about water use habits and tap water characteristics. Two 10-mL whole blood samples were collected from each participant before and immediately after her shower. Levels of individual THM species (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) were measured in whole blood [parts per trillion (pptr)] and in water samples (parts per billion). In the Corpus Christi water samples, brominated compounds accounted for 71% of the total THM concentration by weight; in Cobb County, chloroform accounted for 88%. Significant differences in blood THM levels were observed between study locations. For example, the median baseline blood level of bromoform was 0.3 pptr and 3.5 pptr for participants in Cobb County and Corpus Christi, respectively (p = 0.0001). Differences were most striking in blood obtained after showering. For bromoform, the median blood levels were 0.5 pptr and 17 pptr for participants in Cobb County and Corpus Christi, respectively (p = 0.0001). These results suggest that blood levels of THM species vary substantially across populations, depending on both water quality characteristics and water use activities. Such variation has important implications for epidemiologic studies of the potential health effects of disinfection by-products.

[Syringomyelia discovered in the course of peridural anesthesia]

Neurological symptoms after epidural anaesthesia suggest complications due to anaesthetic procedure. We report the case of a child who underwent perineal surgery in a gynaecological position under general and epidural anaesthesia, who experienced the day after surgery hypoesthesia of the whole left lower limb without any motor deficit. Magnetic resonance imaging excluded spinal compression, but revealed syringomyelic cavity extending from T9 to T11. Electromyogram evaluation was normal. Clinical signs completely vanished within 24 hours. This case emphasizes that the apparition of neurological signs after central nerve blocks is not only a complication of regional anaesthesia, but may reveal unknown neuropathy or result from surgical position or surgical procedure. Meticulous neurological examination, magnetic resonance imaging and electromyogram are immediately required.

Measurement of pulse asymmetry by three-photon-absorption autocorrelation in a GaAsP photodiode

Three-photon absorption in a GaAsP photodiode is used for what is believed to be the first time for nonlinear optical autocorrelation at wavelengths from 1.4 to 1.6microm . Theoretical intensity dependence and contrast ratios are achieved, and the ratio of the three- to the two-photon-absorption coefficient is measured. Finally, it is demonstrated that pulse asymmetry can be measured with no direction-of-time ambiguity by use of unbalanced three-photon-absorption autocorrelation.

Transcriptional organization of the avian adenovirus CELO

A detailed map of the transcriptional organization of the CELO virus genome was produced. Recent computer analysis of CELO virus has indicated the presence of 38 putative open reading frames (ORFs). This study, based on analysis of the transcriptional products of CELO in vitro, confirmed the presence of RNAs for 26 of these 38 ORFs. All of the results were obtained by cDNA isolation or specific reverse transcriptase PCR. Observation of ORF transcription kinetics postinfection revealed the existence of early and late expression, with the earliest starting at 2 h postinfection. The 5' untranslated regions of some RNAs were also studied, and this revealed the existence of a bipartite leader sequence, comparable in structure to the tripartite leader of mastadenovirus. The leader most probably involved in transcriptional activity was observed in most of the structural protein genes of the CELO virus genome. This suggests some homology in transcriptional organization between the avian adenovirus CELO and known mastadenoviruses such as human adenovirus.

Differential transferrin receptor density in human colorectal cancer: A potential probe for diagnosis and therapy

Transferrin receptor density was investigated in human colorectal surgical specimens. Crude membranes were prepared from 23 cancer tumors (adenocarcinoma or malignant villous tumor) and 3 non-cancer tumors (polyadenoma or villous tumor) and 26 adjacent control mucosa. Contrary to non-cancer tumors, Scatchard analysis of 125I-transferrin binding data evidenced higher maximal transferrin binding capacity and lower dissociation constant in cancer tissues (Bmax cancer 1.828+/-0.320 nmol/g, Kd 24.1+/-4.7 nM), as compared to paired control colonic mucosa (Bmax contol 0.851+/-0.182 nmol/g, Kd 30.7+/-7.3 nM), paired t-tests: Bmax p<0.001, Kd p<0.05). As the cancer/control Bmax ratio was 2.6+/-0.4,transferrin carrier constructs should be proposed for cancer imaging or therapy.

Noise reduction in a mode-locked semiconductor laser by coherent photon seeding

We have used coherent photon seeding to reduce the noise in an actively mode-locked extended-cavity semiconductor laser. Feedback is provided by an auxiliary cavity terminated either by a wedge plate or by a phase-conjugate mirror. Both conventional and phase-conjugate feedback can reduce the low-frequency noise components (0-5 MHz) by as much as 36 dB, hence drastically reducing the pulse fluctuations. A noise reduction of as much as 18 dB is also observed in the 0.01-3.0-GHz frequency range. We obtained these results while preserving the pulse duration (26 ps) and improving the time-bandwidth product.

[Hyperthyroidism associated with pulmonary hypertension]

The association of pulmonary hypertension and polyendocrinopathies or connective tissue diseases has been reported by several authors. The causes of this form of pulmonary hypertension are not clear but an autoimmune process has often been proposed. The authors report a case of non-autoimmune hyperthyroidism and reversible pulmonary hypertension after total thyroidectomy and normalisation of thyroid function. This case supports the hypothesis of a non-autoimmune aetiology of some causes of pulmonary hypertension in diseases of the thyroid.

Direct and indirect costs of asthma in Canada, 1990

OBJECTIVE

To calculate the direct and indirect costs of asthma in Canada.

DESIGN

Cost-of-illness study.

SETTING

Canada.

PATIENTS

All Canadians receiving inpatient or outpatient care for asthma in 1990.

OUTCOME MEASURES

Direct costs incurred by inpatient care, emergency services, physician and nursing services, ambulance use, drugs and devices, outpatient diagnostic tests, research and education. Indirect costs from productivity loss due to absence from work, inability to to perform housekeeping activities, need to care for children with asthma who were absent from school, time spent travelling and waiting for medical care, and premature death from asthma. All costs are in 1990 Canadian dollars.

RESULTS

Depending on assumptions, the total cost of asthma was estimated to be between $504 million and $648 million. Direct costs were $306 million. The single largest component of direct costs was the cost of drugs ($124 million). The largest component of indirect costs was illness-related disability ($76 million).

CONCLUSIONS

Annual costs of treating asthma are comparable to the individual cost of infectious diseases, hematological diseases, congenital defects, perinatal illnesses, home care and ambulance services. Asthma costs may increase in the future, given current morbidity and mortality trends. Further evaluation of the effectiveness and cost-effectiveness of available asthma interventions in addition to aggregate cost data are required to determine whether resource allocation for the treatment of asthma can be improved.

Cloning and characterization of the 5' end and promoter region of the chicken acetyl-CoA carboxylase gene

Acetyl-CoA carboxylase is a rate-limiting enzyme in the biogenesis of long-chain fatty acids. In the present study, the 5' end and flanking region of the acetyl-CoA carboxylase (ACC) gene was analysed in the chicken. A genomic clone was isolated containing the first three exons, the third one containing the ATG codon. Using nuclease-mapping experiments and primer-extension analyses, the transcription-initiation site was located 153 nucleotides upstream of the ATG codon. In contrast with rat ACC gene expression, reverse transcriptase PCR analysis performed on chicken liver mRNA did not reveal alternative splicing in the 5'-untranslated region of these messengers. The promoter region is very G+C rich, and contains no TATA or CAAT boxes. Analysis by transient transfection in a human hepatoma cell line (HepG2) demonstrates that the promoter activity requires the presence of symmetrical sequences located upstream of the GC boxes. Transcription of this gene is found to be controlled by tri-iodothyronine in HepG2 cells, but the sequence responsible for the tri-iodothyronine response is not the consensus tri-iodothyronine-responsive element localized in the promoter. These results bring new insights to the regulation of the chicken ACC gene which differs from that of the rat.

Blood lead levels in Toronto children and abatement of lead-contaminated soil and house dust

South Riverdale in Toronto, Canada, underwent a lead-abatement program. In 1988, lead-contaminated soil was replaced at 970 properties, and in 1989, professional housecleaning for lead removal was conducted in 717 households. The effect of "abatement" on blood lead levels in young children was investigated. Data were analyzed from 12 cross-sectional blood-screening surveys that were conducted during an 8-y period in South Riverdale and in two comparison areas. Responses regarding behavioral, household, lifestyle, neighborhood, and environmental factors, all of which were gleaned from associated questionnaires, were also analyzed. Response rates varied between 32% and 75%. During the years between 1984 and 1992, blood lead decreased in all study areas. There appeared to be a minimal blood lead level of 2-3 micrograms/dl for urban Ontario children who were less than 6 y of age. The significant difference between South Riverdale and the control areas disappeared by 1992. Although abatement activity in South Riverdale was associated with an accelerated decline in blood lead levels, it was difficult to distinguish this from effects of decreased Toronto air lead levels or decreased smelter emissions. Within South Riverdale, abatement appeared to be associated with a slower decline in blood lead levels over time, likely the result of selection bias, soil mixing, or recontamination from the smelter. No difference was observed between the separate effects of housecleaning or soil replacement. The findings could neither strongly support nor refute beneficial effects of abatement.

Staff rotation: implications for occupational therapy

Occupational therapy departments of tertiary care hospitals can provide staff with opportunities to gain diverse clinical experience if they rotate through the various services such as surgery, medicine, geriatrics, plastic surgery and orthopaedics. The system of rotation offers both advantages and disadvantages for the staff and the institution. The Royal Victoria Hospital in Montreal, a large university teaching hospital, had traditionally offered staff the opportunity to rotate. Changes in staffing and their needs however, resulted in rotation becoming an important issue within the department. This article presents the pros and the cons of rotation and non-rotation systems as identified by therapists and administrators across Canada. Staff rotation was found to have an effect on job satisfaction and a therapist's career orientation. Given these findings, administrators may want to reconsider the role of the generalist and specialist in their facilities.