Syncope causes transient focal neurological symptoms.

AIMS: The prevalence of focal neurology (FN) as a consequence of syncope is unknown. The aim of the study was to determine its prevalence, risk factors and short-term consequences. METHODS: A consecutive sample of syncope-unit attendees during a 9-month period had detailed diagnostic syncope evaluation as per European Cardiac Society guidelines coupled with assessment for FN present during syncope/pre-syncope by screening questionnaire, follow-up interview and neuroimaging (1.5T magnetic resonance imaging [MRI]). All participants were followed up for 24 months. Risk factors for FN were identified by comparing FN cases with syncope controls without FN (3:1 ratio). RESULTS: Five-hundred and forty consecutively attended for investigation of syncope (n = 401) and pre-syncope (n = 139). Thirty-one (5.7%) had FN events during hypotensive symptoms, mean age 49 years (19-85). The majority of FN cases had vasovagal syncope (VVS); 22 (71%), whereas eight had OH (25.8%) and one (3.2%) had cardiac arrhythmia. Median duration of FN was 15 min (IQR: 34.5). MRI in 28 (90%) was normal and in 3, old cerebral infarction was evident. Risk factors for FN/syncope were frequent syncope (P = 0·008), childhood syncope (P < 0.0005) and delayed diastolic recovery during active stand (P = 0·02). During 24-month follow-up and targeted intervention, no patients developed recurrence of FN. CONCLUSION: One in 20 patients with syncope/pre-syncope have co-extant FN, which during 24-month follow-up, does not progress to a persistent deficit (>24 h). Awareness of co-occurrence of FN and syncope is important as stroke misdiagnosis results in aggressive anti-hypertensive management and future events may ensue.

Effect of anaerobic digestion temperature on odour, coliforms and chlortetracycline in swine manure or monensin in cattle manure.

AIMS: This study evaluated the effect of anaerobic digestion at 22, 38 and 55°C on odour, coliforms and chlortetracycline (CTC) in swine manure or monensin (MON) in cattle manure. METHODS AND RESULTS: Swine or cattle were fed the respective growth promotant, manure was collected, and 2-l laboratory methane digesters were established at the various temperatures and sampled over 25 or 28 days. After 21 days, the concentration of CTC in the 22, 38 and 55°C swine digester slurries decreased 7, 80 and 98%, respectively. Coliforms in the 22°C digester slurries were still viable after 25 days; however, they were not detectable in the 38 and 55°C slurries after 3 and 1 days, respectively. After 28 days, the concentration of MON in the 22, 38 and 55°C cattle digester slurries decreased 3, 8 and 27%, respectively. Coliforms in the 22°C cattle digester slurries were still viable after 28 days; however, they were not detectable in the 38 and 55°C slurries after 14 and 1 days, respectively. CONCLUSIONS: These studies indicate that anaerobic digestion at 38 or 55°C may be an effective treatment to reduce coliforms and CTC; however, it is not an effective treatment to reduce MON. SIGNIFICANCE AND IMPACT OF THE STUDY: More studies are needed to determine which pharmaceuticals are susceptible to degradation by a specific manure treatment to prevent negative environmental consequences.

Effect of mastitis on milk perchlorate concentrations in dairy cows.

Recent surveys have identified the presence of perchlorate, a natural compound and environmental contaminant, in forages and dairy milk. The ingestion of perchlorate is of concern because of its ability to competitively inhibit iodide uptake by the thyroid and to impair synthesis of thyroid hormones. A recent study established that milk perchlorate concentrations in cattle highly correlate with perchlorate intake. However, there is evidence that up to 80% of dietary perchlorate is metabolized in clinically healthy cows, thereby restricting the available transfer of ingested perchlorate into milk. The influence of mastitis on milk perchlorate levels, where there is an increase in mammary vascular permeability and an influx of blood-derived components into milk, remains unknown. The present study examined the effect of experimentally induced mastitis on milk perchlorate levels in cows receiving normal and perchlorate-supplemented diets. Over a 12-d period, cows were ruminally infused with 1 L/d of water or water containing 8 mg of perchlorate. Five days after the initiation of ruminal infusions, experimental mastitis was induced by the intramammary infusion of 100 microg of bacterial lipopolysaccharide (LPS). Contralateral quarters infused with phosphate-buffered saline served as controls. A significant reduction in milk perchlorate concentration was observed in the LPS-challenged glands of animals ruminally infused with either water or perchlorate. In control glands, milk perchlorate concentrations remained constant throughout the study. A strong negative correlation was identified between mammary vascular permeability and milk perchlorate concentrations in LPS-infused glands. These findings, in the context of a recently published study, suggest that an active transport process is operative in the establishment of a perchlorate concentration gradient across the blood-mammary gland interface, and that increases in mammary epithelial and vascular endothelial permeability lead to a net outflow of milk perchlorate. The overall finding that mastitis results in lower milk perchlorate concentrations suggests that changes in udder health do not necessitate increased screening of milk for perchlorate.

Fate of dietary perchlorate in lactating dairy cows: Relevance to animal health and levels in the milk supply.

Perchlorate is a goitrogenic anion that competitively inhibits the sodium iodide transporter and has been detected in forages and in commercial milk throughout the U.S. The fate of perchlorate and its effect on animal health were studied in lactating cows, ruminally infused with perchlorate for 5 weeks. Milk perchlorate levels were highly correlated with perchlorate intake, but milk iodine was unaffected, and there were no demonstrable health effects. We provide evidence that up to 80% of dietary perchlorate was metabolized, most likely in the rumen, which would provide cattle with a degree of refractoriness to perchlorate. Data presented are important for assessing the environmental impact on perchlorate concentrations in milk and potential for relevance to human health.

Contaminant exposure and reproductive success of ospreys (Pandion haliaetus) nesting in Chesapeake Bay regions of concern.

The Chesapeake Bay osprey population has more than doubled in size since restrictions were placed on the production and use of DDT and other toxic organochlorine contaminants in the 1970s. Ospreys are now nesting in the most highly polluted portions of the Bay. In 2000 and 2001, contaminant exposure and reproduction were monitored in ospreys nesting in regions of concern, including Baltimore Harbor and the Patapsco River, the Anacostia and middle Potomac rivers, and the Elizabeth River, and a presumed reference site consisting of the South, West, and Rhode rivers. A "sample egg" from each study nest was collected for contaminant analysis, and the fate of eggs remaining in each nest (n = 14-16/site) was monitored at 7- to 10-day intervals from egg incubation through fledging of young. Ospreys fledged young in regions of concern (observed success: 0.88-1.53 fledglings/active nest), although productivity was marginal for sustaining local populations in Baltimore Harbor and the Patapsco River and in the Anacostia and middle Potomac rivers. Concentrations of p,p'-DDE and many other organochlorine pesticides or metabolites, total PCBs, some arylhydrocarbon receptor-active PCB congeners and polybrominated diphenyl ether congeners, and perfluorooctanesulfonate were often greater in sample eggs from regions of concern compared to the reference site. Nonetheless, logistic regression analyses did not provide evidence linking marginal productivity to p,p'-DDE, total PCBs, or arylhydrocarbon receptor-active PCB congener exposure in regions of concern. In view of the moderate concentrations of total PCBs in eggs from the reference site, concerns related to new and emerging toxicants, and the absence of ecotoxicological data for terrestrial vertebrates in many Bay tributaries, a more thorough spatial evaluation of contaminant exposure in ospreys throughout the Chesapeake may be warranted.

Comparisons of PBDE composition and concentration in fish collected from the Detroit River, MI and Des Plaines River, IL.

Polybrominated diphenyl ethers (PBDEs) were identified in fish collected from the Detroit River, MI and Des Plaines Rivers, IL. In the Detroit River fish, carp and large mouth bass, the congener patterns were dominated by the 2,2',4,4'-tetrabromo (BDE-47) congener, however, in Des Plaines River carp the dominant isomers were the heptabromo congeners BDE-181 and BDE-183 and lesser amounts of another heptabromo congener, BDE-190, and two hexabromo congeners, BDE-154 and BDE-153. Three possible sources exist for these less-commonly identified PBDE congeners: (a) waste discharge from manufacturing or discarded products near the river, (b) public owned treatment work (POTW) effluents which constitute more than 75% of the flow in the Des Plaines River, (c) or formation of these congeners by debromination of in-place deposits of decabromodiphenyl ether. Average concentration totals (sum of concentrations for seven of the dominant PBDE congeners) were similar on a wet weight bases for the carp (5.39 ng/g wet weight) and large mouth bass (5.25 ng/g) in the Detroit River samples; however, the bass were significantly higher, p = 0.01, when compared on a lipid basis (bass--163 ng/g vs. carp--40.5 ng/g lipid weight). Some of the PBDE congeners were positively correlated with increasing lipid levels in both fish species. Average total PBDE concentrations in the carp from the Des Plaines River (12.48 ng/g wet weight) were significantly higher, p = 0.01, than in carp from the Detroit River. The residues were isolated using standard organochlorine methods for fish and analyzed using gas chromatography/mass spectrometry-negative chemical ionization methods.

Treated wood in livestock facilities: relationships among residues of pentachlorophenol, dioxins, and furans in wood and beef.

Wood and other environmental samples were collected from sites that produced beef with higher than average residues of dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF). Analyses of these samples for PCDD/Fs and pentachlorophenol (PCP) indicated that the high beef residues were associated with PCP-treated wood in the animal facilities. Concentrations of PCDD/Fs in wood as toxic equivalents ranged from 10 to 320,000 pg/g. These concentrations were closely related to the concentrations of PCP, indicating that analysis for PCP provides an economical method to identify wood with high concentrations of PCDD/Fs. Further evidence for the PCP-treated wood as the source of the beef residues is provided by the similarity of the congener profiles in beef from the sites and those profiles predicted from the profiles in wood.

Thermodynamic, spectroscopic, and computational evidence for the irreversible conversion of beta- to alpha-endosulfan.

Previous studies have provided unequivocal evidence for the symmetry of beta-endosulfan and the corresponding asymmetry of alpha-endosulfan; the conversion of beta-endosulfan to alpha-endosulfan was identified. In this study, evidence from differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) experiments combined with computational chemistry calculations was used to propose a molecular mechanism for the corresponding conformational changes that occur in this process. DSC and NMR data of mixtures indicated that both isomers can influence the conformer populations in the solid, solution, and vapor phase. Computational chemistry demonstrated that the relative S==O configuration between alpha- and beta-isomers can be the intermediate state through which the conformations of alpha- and beta-isomers affect each other. Furthermore, calculations for mixtures indicated that the asymmetrical conformation of the sulfite in alpha-endosulfan can induce asymmetry in beta-endosulfan, and conversion to alpha-endosulfan occurs from this transition state.

Rapid sequence induction: a questionnaire survey of its routine conduct and continued management during a failed intubation.

Two hundred and ten obstetric anaesthetists completed a questionnaire assessing how they would perform a rapid sequence induction of anaesthesia for a Caesarean section and their continued management during a failed tracheal intubation. The survey revealed considerable variation in the timing and application of cricoid pressure, the choice and dose of drugs used and the timing of their administration. The management of a difficult intubation also varied. This variability was independent of both grade of anaesthetist and frequency of practice. There appear to be at least two distinct techniques in current practice, characterised by 'fast' or 'slow' rapid sequence induction. Rapid sequence induction is clearly not a standard technique and debate is necessary to clarify the risks and benefits of its components. In particular, the rapidity of the technique and the application of cricoid pressure may contribute to the increased incidence of difficult tracheal intubation in obstetric anaesthesia.

Developmental toxicity of PCB 126 (3,3',4,4',5-pentachlorobiphenyl) in nestling American kestrels (Falco sparverius).

Planar PCB congeners are embryotoxic and teratogenic to birds including American kestrels. The developmental toxicity of 3,3',4,4',5-pentachlorobiphenyl (PCB 126) was studied in the posthatching kestrel as a model for the eagle. Nestlings were dosed orally for 10 days with 5 microl/g body weight of corn oil (controls) or the planar PCB 126 at concentrations of 50, 250, or 1000 ng/g body weight. Dosing with 50 ng/g of PCB 126 resulted in a hepatic concentration of 156 ng/g wet weight, liver enlargement and mild coagulative necrosis, over 10-fold increases in hepatic microsomal ethoxyresorufin-O-dealkylase and benzyloxyresorufin-O-dealkylase, and approximately a 5-fold increase in methoxyresorufin-O-dealkylase. At this dose, mild to moderate lymphoid depletion of the spleen was apparent, as were decreased follicle size and content of the thyroid. At 250 ng/g, concentration of PCB 126 in the liver was 380 ng/g with increasing multifocal coagulative necrosis, decreased bone growth, decreased spleen weight with lymphocyte depletion of the spleen and bursa, and degenerative lesions of the thyroid. At 1000 ng/g, the liver concentration was 1098 ng/g, accompanied by decreased bursa weight, decreased hepatic thiol concentration, and increased plasma enzyme activities (ALT, AST, and LDH-L) in addition to the previous effects. Highly significant positive correlations were noted between liver concentrations of PCB 126 and the ratio of oxidized to reduced glutathone. These findings indicate that nestling kestrels are more susceptible to PCB 126 toxicity than adults, but less sensitive than embryos, and that planar PCBs are of potential hazard to nestling birds.

Determination of mutational spectrum of the pesticide, captan, with an improved set of Escherichia coli LacZ mutants.

The mutational spectrum of the fungicide, captan, was determined using a set of improved Escherichia coli lacZ mutants. Captan created mutations mostly at dA-dT sites (83%) with only 17% occurring at dG-dC sites. The hydrolysis products of captan do not appear to be mutagenic because samples of captan at different hydrolysis stages showed basically the same mutational spectra: 31% at AT --> CG transversions, 8% of GC --> AT transitions, 2% of GC --> CG transversions, 8% of GC --> TA transversions, 19% of AT --> TA transversions, and 32% of AT --> GC transitions. Prepared solutions of captan lost their mutational activity gradually over time, indicating that the rate of decrease in mutagenicity agreed with the kinetics of captan hydrolysis reported in other studies. Using the change in mutagenicity to predict degradation, the hydrolysis of captan in pH 7.0 buffer was about three times faster than the hydrolysis carried out in pH 4.5 buffer. To our knowledge, this is the first presentation of mutational spectrum of captan.

Environmental contaminants in nonviable eggs of the endangered Mississippi sandhill crane (Grus canadensis pulla).

Our objectives were to determine if concentrations of environmental pollutants and microbial contamination in nonviable eggs of the endangered Mississippi sandhill crane (Grus canadensis pulla) contributed to egg failure. Six eggs collected in 1990 and four in 1991 contained only background levels of organochlorine pesticides and polychlorinated biphenyls (PCBs), and tests for microbial contamination were all negative. Two eggs contained late dead embryos, but neither revealed obvious abnormalities. Three eggs contained potentially harmful concentrations (23, 39, 146 pg/g, wet mass) of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), based on 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ) for combined compounds. Because of the scarcity of material suitable for laboratory examination and the endangered status of the crane, we recommend that nonviable eggs continue to be monitored for toxic pollutants.

Strategies and faculty roles for teaching RN students.

To help maximize the learning of RN students, the author discusses strategies and faculty roles that are particularly effective with these students. Methodologies from nursing practice, supervision, and management, combined with principles from adult education, provide the basis for this success-oriented approach.

The biomagnification of polychlorinated biphenyls, toxaphene, and DDT compounds in a Lake Michigan offshore food web.

The biomagnification of polychlorinated biphenyls (PCB), toxaphene, and the DDT family of metabolites was investigated in the epibenthic Mysis relicta (mysid), the benthic Pontoporeia hoyi (amphipod), plankton, particulate flux, surficial sediments, and Myoxocephalus thompsoni (deepwater sculpin) in southeastern Lake Michigan. DDE was the most strongly biomagnified compound, increasing 28.7 times in average concentration from plankton to fish. PCB increased 12.9 times in average concentration from plankton to fish while toxaphene increased by an average factor of 4.7. Particle flux was comprised of lower chlorinated PCB homologues (average chlorine number = 3.8) than the biota (4.5-5.0) and sediments (4.6), possibly reflecting strong influences from atmospheric deposition and/or zooplankton egestion. The percent of higher chlorinated PCB homologues (5 and 6 chlorine atoms per PCB molecule) increased from 54-56% of the total PCB in plankton and M. relicta, to 61% in P. hoyi, to 74% in sculpins. Amphipods contained greater concentrations than mysids of PCB, DDT residues, and toxaphene, possibly reflecting differences in habitat (benthic vs epibenthic) and diet (detritus vs plankton). Based on estimates of average areal biomass and contaminant concentration, offshore Lake Michigan P. hoyi populations contain approximately 15.0 times as much toxaphene, 9.5 times as much total DDT, and 12.0 times as much PCB as the offshore M. relicta populations. Thus, amphipods may represent a greater reservoir than mysids for contaminant storage and subsequent recycling in offshore Lake Michigan.

Analgesic effect of ethyl alcohol.

The analgesic properties of ethyl alcohol administered i.v. were investigated, using elevation of the pain threshold for applied somatic stimuli as an index. Alcohol proved markedly superior to saline in this respect and produced an effect equivalent to that of i.v. morphine.