Predictive properties of a qualitative urine acetaminophen screen in patients with self-poisoning

OBJECTIVE

Screening for acetaminophen toxicity is recommended in almost all cases of self poisoning. We compared a qualitative urine acetaminophen screen to the quantitative serum acetaminophen to test the hypothesis that a negative urine acetaminophen screen would be predictive of a negative serum acetaminophen level.

METHODS

All adults with intentional ingestions evaluated in our Emergency Department during 1995 were retrospectively identified based on Emergency Department International Classification of Disease--9th edition codes. Laboratory data from each patient including serum and urine toxicologic assays were examined. Predictive properties of urine acetaminophen screens for serum acetaminophen were evaluated.

RESULTS

A total of 88 patients were identified who had both a serum acetaminophen and a urine acetaminophen performed. The sensitivity of the urine acetaminophen screen was 100% (95% CI 72-100%) and the specificity was 87% (95% CI 80-95%). All patients with negative urine acetaminophen screens had negative serum acetaminophen levels (negative predictive value 100%; 95% CI 96-100%). Accuracy of the urine acetaminophen screen was 89%.

CONCLUSION

A negative urine acetaminophen screen was highly predictive of negative serum acetaminophen levels. It is possible that negative urine acetaminophen screens may obviate the need for 4-hour quantitative serum levels. Further validation in a prospective study is needed.

A community hospital's effort to expedite treatment for patients with chest pain

OBJECTIVE

The purpose of this study was to determine treatment times at a community hospital that does not receive prehospital electrocardiogram (ECG) transmission and to determine the effect of time to first hospital ECG on overall door-to-drug time.

DESIGN

Descriptive.

SETTING

238-bed Regional Medical Center in Burlington, North Carolina.

SAMPLE

One hundred four patients with a final diagnosis of acute myocardial infarction were included in this 16-month study.

RESULTS

A median door-to-ECG time of 5 minutes was within the American College of Cardiology/American Heart Association recommendation of 10 minutes. Shorter treatment times to obtain the first ECG and initiate thrombolytic therapy were associated with younger patients and those arriving by ambulance.

CONCLUSIONS

While efficiency in obtaining a first hospital ECG on patients with suspected acute myocardial infarctions was achieved, this did not result in low door-to-drug times. Further streamlining of protocol and the exploration of prehospital initiatives may result in a significant reduction in door-to-drug times.

The presence of N-acetylneuraminic acid in Malpighian tubules of larvae of the cicada Philaenus spumarius

Sialic acid-containing glycoconjugates are generally considered to be unique to the deuterostomes, a lineage of the animal kingdom which includes animals from the echinoderms up to the vertebrates. There are, however, two isolated reports of sialic acid occurring in the insect species Drosophila melanogaster and Galleria mellonella. Since insects are classified as protostomes, these findings call previous assumption on the phylogenetic distribution and thus on the evolution of sialic acids into question. Here, we report the occurrence of N-acetylneuraminic acid (Neu5Ac) in larvae of the cicada Philaenus spumarius. Cytochemical analysis of larval sections with lectins from Sambucus nigra and Limax flavus suggested the presence of sialic acids in the concrement vacuoles of the Malpighian tubules. The monoclonal antibody MAb 735, which is specific for polysialic acid, labelled the same structures. A chemical analysis performed by HPLC of fluorescent derivatives of sialic acids and by GLC-MS provided sound evidence for the presence of Neu5Ac in the Philaenus spumarius larvae. These data suggest that in this cicada Neu5Ac occurs in alpha2,8-linked polysialic acid structures and in alpha2,6-linkages. The results provide further evidence for the existence of sialic acids in insects and in linkages known to occur in glycoconjugates of deuterostomate origin.

A comparison of sampling and analytical methods for assessing occupational exposure to diesel exhaust in a railroad work environment

Methods of assessing occupational exposure to diesel exhaust were evaluated in a railroad work environment. The American Conference of Governmental Industrial Hygienists (ACGIH)-recommended elemental carbon and respirable combustible dust methods of sampling and analysis for assessing diesel exhaust were included in the study. A total of 215 personal and area samples were collected using both size-selective (nylon cyclone and Marple) and non-size-selective samplers. The results demonstrate that the elemental carbon method is suitable for the railroad environment and the respirable combustible dust method is not. All elemental carbon concentrations measured were below the proposed ACGIH Threshold Limit Value (TLV) of 0.15 mg/m3. The concentrations of oxides of nitrogen (nitric oxide and nitrogen dioxide) were also found to be below their respective TLVs. There is no correlation between elemental carbon or respirable combustible dust and the oxides of nitrogen. The elemental carbon as fraction of total carbon is about 13 percent, except for onboard locomotives where it is about 24 percent. Comparison of elemental carbon and respirable combustible dust measurements showed consistent relationships for most sampling locations, with respirable combustible dust concentrations 12 to 53 times higher than the elemental carbon levels.

Laboratory confirmation of scopolamine co-intoxication in patients using tainted heroin

BACKGROUND

First described in 1995, at least 325 patients with a history of heroin use have since required emergency medical evaluation in several eastern US cities, because of an anticholinergic toxidrome following use of heroin. This co-intoxication has been alleged to result from an atropine-like compound. We report the clinical findings and laboratory analysis of one of several individuals who presented to our Emergency Department during this epidemic.

CASE REPORT

A 23-year-old male was one of 3 patients brought to the Emergency Department due to agitated behavior after insufflating heroin. Following physical and chemical restraint, vital signs were pulse 134 bpm, BP 160/90 mm Hg, RR 24/min, and T 37.3 degrees C. Physical examination was remarkable for dilated pupils 8-9 mm without nystagmus, along with dry mouth, decreased bowel sounds, and flushed dry skin. A bladder catheter was placed and 500 mL of urine was obtained. Electrocardiogram revealed sinus tachycardia only. Additional sedation was required for 12 hours until normal mental status returned. A small sample of the "heroin" used was obtained and analyzed. Scopolamine was confirmed by gas chromatography-mass spectrometry. Further evidence of scopolamine intoxication was supported by identifying scopolamine in the urine of this patient.

CONCLUSION

Gas chromatography-mass spectrometry revealed scopolamine to be the cause of anticholinergic findings in a patient following use of tainted heroin. It is unclear whether scopolamine is an adulterant or contaminant in this heroin. Patients with anticholinergic findings following use of heroin may be co-intoxicated with scopolamine.

Can cardiovascular clinical characteristics be identified and outcome models be developed from an in-patient claims database?

The objective of this study was to assess whether administrative (claims) databases can be used to assess clinical variables and predict outcome. Although administrative databases are useful for assessing resource utilization, their utility for assessing clinical information is less certain. Prospectively gathered clinical databases, however, are expensive and not widely available. The UB92 formulation of the hospital bill was used as an administrative source of data and compared with the clinical cardiovascular database at Emory University. The claims database was compared with the clinical database for 11 variables. Outcome models were developed with multivariate methods. A total of 11,883 patients who underwent catheterization (5,255 underwent percutaneous transluminal coronary angioplasty [PTCA] and 3,794 underwent coronary artery bypass surgery [CABG]) between 1991 and 1995 were included. For some variables, the claims database correlated well (diabetes, sensitivity 87%, specificity 99%), whereas for others the claims database was less accurate (peripheral vascular disease, sensitivity 20%, specificity 99%). Uncertain coding in the claims database, which can result in the same code being used for co-morbid states and severity of disease, as well as complications, limited the ability of claims to predict outcome. Clinical databases may also be limited by lack of objectivity and missing data. The utility of claims databases to assess severity of disease and co-morbid states is limited, and outcome modeling and risk assessment from claims databases may be inappropriate and spurious. Developing better data standards and less expensive methods for acquisition of clinical data is necessary for improved outcome assessment.

Repetitive strain injuries in dentistry

In order to avoid RSI, try to neutralize, modify and energize at work, home and play. These concepts eliminate the risk factors associated with the development of RSI and optimize an individual's physical capabilities to work productively and efficiently. People suffering with an RSI should consult their physician regarding the various treatment options available to them. Ideally, prevention is the key to reducing the costs and problems associated with RSI. However, an individual suffering with RSI should not delay addressing the injury. Treatment is most effective when applied as soon as possible after the onset of injury.

Dental erosion--the problem and some practical solutions

There has been a clinical impression among dental practitioners, particularly those working with children, that the problem of dental erosion is increasing. Is this really the case or are we more aware of the problem? What is causing this increase, if it really exists? Perhaps more importantly, what can we do about it? This article looks at the prevalence, and aetiology of dental erosion, particularly in children, and makes some practical suggestions for possible control.

Effect of exogenous FSH on ovulation rate in homozygous carriers or noncarriers of the Booroola FecB gene after hypothalamic-pituitary disconnection or after treatment with a GnRH agonist

We have tested the hypothesis "that the ovulation rate in homozygous carriers (BB) and noncarriers (+2) of the Booroola FecB gene would not be different if the plasma concentrations of follicle-stimulating hormone (FSH) in the two genotypes were similar." For this purpose we used two experimental animal models: 1) the hypothalamic-pituitary disconnected (HPD) ovary-intact ewe; and 2) and GnRH agonist (i.e., Deslorelin)-treated ewe. Following HPD or Deslorelin treatment, the animals had low plasma concentrations of gonadotropins and were anovulatory. In both animal models, BB and +2 ewes were treated with exogenous pregnant mares serum gonadotropin (PMSG) and varying doses of FSH to induce preovulatory follicular growth, and human chorionic gonadotropin (hCG) to induce ovulation. HPD or Deslorelin-treated animals administered with pregnant mares serum gonadotropin without FSH followed by human chorionic gonadotropin failed to ovulate. However for both animal models, the proportion of BB and +2 ewes ovulating to various doses of FSH differed such that significantly greater proportions of +2 animals ovulated relative to the BB genotype (P < 0.05). When HPD or Deslorelin-treated BB and +2 ewes were administered identical doses of FSH, the mean ovulation rate and plasma concentrations of FSH in those animals which ovulated was the same in both genotypes. These findings confirm, at least in part, the aforementioned hypothesis. The results also demonstrated that higher ovulation rates were obtained in both genotypes as the FSH dose was increased. Collectively, these findings infer that the higher mean ovulation rate in normal intact BB ewes compared to the +2 genotype is attributable to effects of the FecB gene at the level of ovarian follicular development as well as at the level of pituitary FSH release.

Endothelin-1 stimulates hydrolysis of phosphatidylcholine by phospholipases C and D in intact rat mesenteric arteries

A characteristic of endothelin-1 (ET-1)-induced contraction is the prolonged duration of the response. Phosphatidylcholine (PC) hydrolysis has been implicated in sustained agonist-induced effects through the formation of the second messengers phosphatidic acid (PA) and diacylglycerol (DAG). Therefore, we have investigated the activation of PC-phospholipase D (PLD) and PC-phospholipase C (PLC) in intact rat mesenteric small arteries stimulated with ET-1 and determined whether PC-derived DAG is necessary for ET-1-induced contraction. PLD activity, measured as phosphatidylethanol (PEt) production in vessels labelled with [3H] or [14C]myristate, was increased in a concentration- and time-dependent manner following ET-1 stimulation, as were [3H]PA levels, peaking at 10 min (ET-1 100 nM) and remaining above control levels for up to 20 min. Inclusion of 0.5% ethanol during ET-1 stimulation reduced [3H]PA levels, but did not alter the time course of formation. In addition, [14C]choline release was increased, confirming PLD-mediated PC hydrolysis. In contrast, DAG levels, measured by [3H]myristate labelling and mass assay, increased transiently at 5 min of ET-1 stimulation only. Analysis of the subclasses of DAG demonstrated an increase in all types of DAG without any enrichment with arachidonate-containing species, indicating PC, not inositol lipid hydrolysis was the source of DAG. The PC-PLC inhibitor D609, 2.5 microg/ml, completely abolished the ET-1-induced increase in [14C]DAG without affecting the increase in [14C]PA, PLD activity or the contractile response. In [14C]choline-labelled vessels, [14C]phosphocholine levels were increased by ET-1 with a similar time course to DAG production. Removal of extracellular Ca2+ and addition of 0.1 or 2 mM EGTA completely inhibited ET-1-stimulated PLD activity. The tyrosine kinase inhibitor tyrphostin A23 (100 microM) abolished ET-1-induced [3H]PA, [3H]PEt and [14C]DAG increases, whilst the negative analogue A1 was without effect. These data suggest that ET-1 couples via a calcium-dependent tyrosine kinase mechanism to PLD and PC-PLC in vascular smooth muscle. PC-derived DAG did not appear to be necessary for the contractile response, whereas sustained formation of PA, generated by PLD activity, implies that this lipid second messenger could be involved in the prolonged contractile response to this peptide.

Tooth wear in children: an investigation of etiological factors in children with cerebral palsy and gastroesophageal reflux

This investigation was undertaken to establish the prevalence and distribution of tooth wear in different groups of medically compromised children and to assess the possible influence of gastroesophageal reflux, dietary factors, and parafunctional activity. Four groups of children including twenty-one with cerebral palsy were clinically examined and had in-depth, structured interviews, including information on medical history, medication, gastroesophageal reflux, feeding and drinking habits, parafunctional activity, and tooth-brushing procedures. All the children with cerebral palsy also had twenty-four-hour gastroesophageal pH monitoring. Of the fifty-one children in total, twenty-five had moderate or severe levels of dental erosion. No statistically significant differences were found between the groups as far as dietary influences, feeding habits, and tooth-brushing procedures. There was a significant association, however, between gastroesophageal reflux and erosion. It is concluded that in children with cerebral palsy this reflux may be much more important in the etiology of tooth surface loss than the parafunctional activity, which has classically been regarded as the cause.

The role of CMP-N-acetylneuraminic acid hydroxylase in determining the level of N-glycolylneuraminic acid in porcine tissues

The biosynthesis of the sialic acid N-glycolylneuraminic acid (Neu5Gc) occurs by the action of cytidine monophosphate-N-acetylneuraminate (CMP-Neu5Ac) hydroxylase. Previous investigations on a limited number of tissues suggest that the activity of this enzyme governs the extent of glycoconjugate sialylation with Neu5Gc. Using improved analytical procedures and a panel of nine porcine tissues, each expressing different amounts of Neu5Gc, we have readdressed the issue of the regulation of Neu5Gc incorporation into glycoconjugates. The following parameters were measured for each tissue: the molar ratio Neu5Gc/Neu5Ac, the activity of the hydroxylase, and the relative amount of hydroxylase protein, as determined by enzyme-linked immunosorbent assay (ELISA). A positive correlation between the activity of the hydroxylase and the molar ratio Neu5Gc/Neu5Ac was observed for each tissue. In addition, the hydroxylase activity correlated with the amount of enzyme protein, though in heart and lung disproportionately large amounts of immunoreactive protein were detected. Taken together, the results suggest that the incorporation of Neu5Gc into glycoconjugates is generally controlled by the amount of hydroxylase protein expressed in a tissue.

Problems associated with nursing staff shortage: an analysis of the first 3600 incident reports submitted to the Australian Incident Monitoring Study (AIMS-ICU)

Although many studies have attempted to define appropriate nursing staff levels, allocation and patient dependency, minimal data is available on the effect of nursing staff shortage (NSS) on quality of care provided in intensive care. This study aimed to identify incidents associated with staff shortage as reported to the Australian Incident Monitoring Study-ICU (AIMS-ICU) project and to assess their estimated effect on patient outcome. A search of narrative keywords and contributing factors identified 89 nursing staff shortage incidents (NSS-INCIDENTS) and 373 incidents involving nursing staff shortage contributing factors (NSS-CF). NSS resulted from inappropriate rostering for current patient load (81%) and inability to respond to increased unit activity (19%). Most frequent associated incidents included problems with: drug administration/documentation (47), patient supervision (20), set-up of ventilators/equipment (16), and accidental extubation (14). Undesirable patient outcomes included: major physiological change (22%), patient/relative dissatisfaction (12%), and physical injury (3%). This study suggests that inadequate staffing results in incidents and compromised patient safety.

Urinary calcium/creatinine ratio as a predictor of preeclampsia

Hypocalciuria has been associated with preeclampsia (gestational hypertension with proteinuria or other maternal organ dysfunction) but not usually with pure gestational hypertension or normal pregnancy. We hypothesized that hypocalciuria would be a marker of emerging preeclampsia in women presenting with gestational hypertension who later developed preeclampsia. Eighty-one women with de novo hypertension in the second half of pregnancy (n = 81) were enrolled prospectively. At first assessment, calcium/creatinine ratio was determined in a spot urine. Patients were followed until delivery and were classified subsequently according to the occurrence of preeclampsia. Gestational hypertensive patients who became preeclamptic (n = 31) had lower urinary calcium/creatinine ratios at presentation (ratio = 0.07, interquartile range [IQR] = 0.04-0.11) than women who remained as gestational hypertensives (n = 50; ratio = 0.17, IQR = 0.08-0.21; P = .002). Intact plasma parathyroid hormone (PTH) concentrations were similar between groups. Using a receiver operator curve, the best threshold value for the development of preeclampsia was a calcium/creatinine ratio of 0.10, which yielded a sensitivity of only 68% and a specificity of 70%. A low calcium/creatinine ratio preceded the emergence of preeclampsia by 12 (7-24) (median [IQR]) days among a group of women with gestational hypertension. Though this implies primary or secondary disturbances of renal calcium handling even before preeclampsia is clinically apparent, this measurement does not have sufficient sensitivity to recommend its use as a screening test for the emergence of preeclampsia.

Antigen-independent suppression of the IgE immune response to bee venom phospholipase A2 by maternally derived monoclonal IgG antibodies

The IgE immune response to ovalbumin in rats can be suppressed by prior immunization of the dams. The results reported in this paper extend this observation to include a different antigen and another species, namely the IgE immune response to bee venom phospholipase A2 (PLA2) in CBA/J mice. The degree of suppression seemed to depend on the amount of IgG antibodies transferred to the offspring. Moreover, we found that the maternally mediated suppression of the IgE response could be achieved in a completely antigen-free system in which exogenous monoclonal anti-PLA2 IgG antibodies were transferred from the dams to the offspring. The following results were obtained: (i) The IgE suppression by monoclonal IgG antibodies was induced as efficiently with one single anti-PLA2 IgG1 antibody as with a mixture of ten antibodies (nine IgG1, one IgG2b). (ii) Even after several immunizations up to an age of 6 months with a dose of PLA2 that normally induces IgE production, none of the F1 mice developed an IgE response. (iii) This long-lasting suppression was observed in mice which were first immunized at an age of 4 weeks (i.e. when low amounts of maternally derived monoclonal IgG were still present), as well as in mice which were first immunized at an age of 8 weeks, when no such maternal antibodies could be detected in their sera. The corresponding IgG responses showed, compared to normal mice, a transient enhancement in the maternally influenced mice. It is concluded that the immunological experience of the mother is of particular importance for the isotype regulation in the newborns, especially with respect to the ability to elicit an IgE response. The possible implications for the development of allergic diseases in humans are discussed.

Cytidine monophosphate-N-acetylneuraminate hydroxylase in the starfish Asterias rubens and other echinoderms

The sialic acid N-glycolylneuraminic acid (Neu5Gc) is synthesised by an NADH-dependent hydroxylase which acts on CMP-N-acetylneuraminic acid (CMP-Neu5Ac). Although Neu5Gc is the predominant sialic acid in many echinoderms, little is known about the hydroxylase from organisms of this phylum. We show here that in contrast to the mammalian enzyme, the hydroxylase from various echinoderms is predominantly membrane-bound and exhibits optimal activity in the presence of 100 mM NaCl. A detailed characterisation of the hydroxylase from echinoderms was performed using fractionated gonads of the starfish Asterias rubens. Solubilisation using detergents led to an inactivation of the hydroxylase. However, the solubilised enzyme was reactivated by the addition of cytochrome b5 reductase together with the amphiphilic or soluble form of cytochrome b5. Although these latter proteins were only available from a mammalian source, the high affinity of the hydroxylase for cytochrome b5 suggests that, as with the mammalian enzyme, these electron carriers participate in the catalytic cycle of the hydroxylase from A. rubens in vivo. The relevance of these results to the interaction between cytochrome b5 and the hydroxylase is discussed.

Australian Incident Monitoring Study in intensive care: local unit review meetings and report management

The Australian Incident Monitoring Study in the intensive care unit (AIMS-ICU) is a national study established through nursing and medical collaboration to develop, introduce and evaluate an anonymous voluntary incident reporting system. To ensure incident monitoring results in improved patient safety, it is essential that reported incidents are followed up regularly. Local unit review meetings are an effective forum for discussion and review of reports amongst a wide group of practitioners from the intensive care unit (ICU). All staff should be invited to participate in order to suggest preventative strategies, report on incident follow up and explore national study findings. Ongoing momentum of the project is assisted by highlighting its positive contributions to patient care and safety via newsletters, poster displays and targeted correspondence. New staff require orientation to the reporting system and assurance regarding safety of data. The emphasis must focus on the system, not the individual.

The biosynthesis of 8-O-methylated sialic acids in the starfish Asterias rubens--isolation and characterisation of S-adenosyl-L-methionine:sialate-8-O-methyltransferase

The unusual, 8-O-methylated sialic acids have only been found in glycoconjugates of certain species of starfish. Using a detergent-solubilised extract of a particulate fraction from gonads of Asterias rubens, a specific methylation of endogenous and exogenous glycoconjugate-bound sialic acids was detected with [14C]-S-adenosyl-L-methionine ([14C]AdoMet) as the methyl donor. For this test, a filtration assay was developed using glutardialdehyde-fixed horse erythrocyte membranes as methyl acceptor. The enzyme catalysing this reaction, the sialate-8-O-methyltransferase, was purified 22000-fold in a yield of 13% by ion-exchange chromatography and two cycles of affinity chromatography on S-adenosyl-L-homocysteine-Sepharose. Upon SDS/PAGE under reducing conditions, the purified sialate-8-O-methyltransferase revealed two bands with apparent molecular masses of 58 kDa and 62 kDa. Since no evidence for the presence of subunits was found, the relationship between these two species is unknown. The enzyme was optimally active over a broad range of pH (7.4-8.3) and at 37 degrees C. After EDTA treatment, restoration of the activity depended, in contrast to most methyltransferases, on Mn2+ or Co2+, the latter to a lesser extent. Although both, free N-acetylneuraminic acid and N-glycoloylneuraminic acid were methylated, sialic acids alpha-glycosidically bound to a number of oligosaccharides and glycoproteins were better substrates. In the presence of 20 microM AdoMet, apparent Km values of 299 microM and 44 microM were found for N-acetylneuraminic acid and N-acetylneuraminyl alpha2,3-lactose, respectively. Using N-acetylneuraminyl alpha2,3-lactose as acceptor, an apparent Km of 7.1 microM was found for S-adenosyl-L-methionine. Therefore, the sialate-8-O-methyltransferase is the first enzyme known to modify both free and glycoconjugate-bound sialic acids.