Senior house officers' work activities in an accident and emergency department

A study of senior house officers' daytime work activities was conducted in the accident and emergency department of the Cardiff Royal Infirmary. Activities were timed every 15 seconds by a single observer and were subdivided into working periods, meal periods and periods when no patient was waiting to be seen. A total of 96.1 h was analysed. The SHOs were found to be working for 78% of their time, of which 18.5% was taken up by non-doctor tasks. The SHOs took an average of 10.4 min for each walking wounded patient, 10.6 min for each paediatric patient and 27.3 min for a trolley patient. Each patient required an average of 14.2 min for assessment and treatment, which meant that 3.3 patients were seen each hour. However, considering that SHOs worked for 78% of their time, the actual rate of work was 4.2 patients for each working hour. The implications for staffing are discussed.

Use of BACTEC radiometric culture method and polymerase chain reaction for the rapid screening of faeces and tissues for Mycobacterium paratuberculosis

The BACTEC radiometric culture method for detection of Mycobacterium paratuberculosis was evaluated on faeces from cattle on a farm in quarantine for Johne's disease. A multiplex polymerase chain reaction (PCR) based on the IS900 sequence specific for M paratuberculosis and a genus specific 16S rRNA region was developed and used to test cultures showing evidence of mycobacterial growth in the BACTEC liquid radiometric culture medium. Using the BACTEC-PCR combination, confirmation of M paratuberculosis from faeces and tissue of clinically affected animals was achieved within 2 to 4 weeks and 1 week, respectively, a substantial improvement on traditional culture and identification methods. The PCR provided rapid exclusion of M paratuberculosis when other Mycobacterium spp were grown. The radiometric culture medium proved to be very sensitive for culturing Mycobacterium spp.

Intraosseous infusion--a technique available for intravascular administration of drugs and fluids in the child with burns

Intraosseous infusion is a potential route for intravenous access in the child with burns who required vascular access that cannot be achieved in a timely manner via another route. Drugs, fluid and blood can be given via this route and marrow aspirate drawn for laboratory analysis. It is a reliable, safe procedure with a low incidence of complications.

A two-reporter gene system for the analysis of bi-directional transcription from the divergent MAL6T-MAL6S promoter in Saccharomyces cerevisiae

Many sets of genes in Saccharomyces cerevisiae are divergently transcribed, but at present there are no vectors generally available for the simultaneous analysis of divergent transcription from these promoters. In the present study MEL1 and lacZ were used to construct a vector capable of measuring the divergent expression initiated by the MAL6T-MAL6S bi-directional promoter. Our observations demonstrate that the expression of both reporter genes was regulated in a similar fashion to the native MAL6T and MAL6S genes, and that induction was dependent upon the presence of a functional MALR activator gene. The results confirmed that the MAL6T-MAL6S promoter was co-ordinately regulated, repressed by glucose, induced by maltose, and that basal expression was more active in the MAL6S direction than in the MAL6T direction.

Pharmacological characterization of heterologously expressed ATP-gated cation channels (P2x purinoceptors)

cDNAs encoding P2x purinoceptors from human bladder smooth muscle and from rat PC-12 cells were expressed in oocytes and human embryonic kidney 293 cells. Agonist potencies of 2-methylthio-ATP = 2-chloro-ATP = ATP > = 2'- and 3'-O-(4-benzoylbenzoyl)-ATP > or = adenosine-5'-O-(3-thio)-triphosphate > or = P1,P5-di(adenosine-5') pentaphosphate >> ADP prevailed for both P2x purinoceptors. There were two main differences in agonist sensitivity between the two receptors. First, ATP was 10 times more potent at the receptor from bladder (EC50, 0.8 microM) than at the receptor from PC-12 cells (EC50, 8.2 microM). Second, alpha,beta-methylene-ATP and L- and D-beta,gamma-methylene-ATP were agonists in cells expressing the bladder smooth muscle receptor (EC50, 1-3 microM) but were ineffective in cells expressing the PC-12 receptor. The P2 purinoceptor antagonists suramin, pyridoxal phosphate 6-azophenyl-2',4'-disulfonic acid, and pyridoxal-5-phosphate acted similarly at both receptor forms, producing noncompetitive inhibition, with IC50 values of 1-5 microM for suramin and pyridoxal phosphate 6-azophenyl-2',4'-disulfonic acid and 10-20 microM for pyridoxal-5-phosphate. 4,4'-Diisothiocyanatostilbene-2,2'-disulfonic acid distinguished receptor subtypes, producing potent inhibition of the bladder smooth muscle P2x-mediated response, with an IC50 value of 3 microM; it inhibited the PC-12 form by < 40% at 100 or 300 microM. This study thus defines the pharmacological properties of homo-oligomeric forms of these two types of cloned P2x receptor channels.

Long-term inhibition of murine experimental autoimmune encephalomyelitis using CTLA-4-Fc supports a key role for CD28 costimulation

T cell activation involves not only recognition of antigen presented by the MHC, but also nonspecific interactions termed "costimulation." The costimulatory molecules B7-1 and B7-2 are ligands on antigen-presenting cells for the CD28 and CTLA-4 receptors on T cells. Previously, a fusion protein consisting of human CTLA-4 linked to human Fc was shown to bind B7-1 and B7-2 with high avidity and to prevent specific T cell activation. Here we investigated the effects of a recombinant fusion protein consisting of the extracellular domain of human CTLA-4 bound to mouse IgG2a Fc (CTLA-4-Fc) upon experimental autoimmune encephalomyelitis, a T cell-mediated disease that serves as a model for multiple sclerosis. CTLA-4-Fc prevented experimental autoimmune encephalomyelitis in 26 of 28 CTLA-4-Fc-treated mice (median maximum score 0), whereas 28 of 30 mice treated with control mouse IgG2a developed disease (median maximum score 2.75). Less inflammation and virtually no demyelination or axonal loss occurred in CTLA-4-Fc-treated compared with control-treated mice. Activated splenocytes from CTLA-4-Fc-treated mice were able to transfer disease adoptively to naive recipients. These results indicate a key role for the B7/CD28 system in the development of actively induced murine experimental autoimmune encephalomyelitis, suggesting an area of investigation with therapeutic potential for multiple sclerosis.

Mapping receptor binding sites in interleukin (IL)-1 receptor antagonist and IL-1 beta by site-directed mutagenesis. Identification of a single site in IL-1ra and two sites in IL-1 beta

Interleukin-1 receptor antagonist (IL-1ra), an IL-1 family member, binds with high affinity to the type I IL-1 receptor (IL-1RI), blocking IL-1 binding but not inducing an IL-1-like response. Extensive site-directed mutagenesis has been used to identify residues in IL-1ra and IL-1 beta involved in binding to IL-1RI. These analyses have revealed the presence of two discrete receptor binding sites on IL-1 beta. Only one of these sites is present on IL-1ra, consisting of residues Trp-16, Gln-20, Tyr-34, Gln-36, and Tyr-147. Interestingly, the absent second site is at the location of the major structural difference between IL-1ra and IL-1 beta, which are otherwise structurally similar. The two receptor binding sites on IL-1 beta are also present on IL-1 alpha. Thus, it appears that the two IL-1 agonist molecules have two sites for IL-1RI binding, and the homologous antagonist molecule, IL-1ra, has only one. Based on these observations, a hypothesis is presented to account for the difference in activity between the agonist and antagonist proteins. It is proposed that the presence of the two receptor binding sites may be necessary for agonist activity.

Fatal acute pancreatitis caused by valproic acid

We describe a case of a 31-year-old woman with cerebral palsy who developed fatal acute hemorrhagic pancreatitis while being treated with valproic acid to control her seizure activity. Acute pancreatitis is usually due to alcohol ingestion or biliary tract disease, and unusual causes include trauma, metabolic diseases, or drugs. Valproic acid is considered a safe drug, although rare cases of severe toxicity such as hepatitis and acute pancreatitis, including two fatalities, have been reported. Our review of the literature revealed that most patients who developed acute pancreatitis had serum levels of the drug within the therapeutic range, and most of the cases occurred either secondary to a recent increase in the dose or to initiation of treatment. It also appeared that the fatalities occurred due to a delayed diagnosis of acute pancreatitis, either resulting from an unsuspected diagnosis or to the deteriorated mental status of the patients receiving the drug, which precluded their ability to elaborate symptomatology. We believe that early diagnosis and withdrawal of the drug are significant factors determining the course of valproic-acid-associated pancreatitis.

Endotoxin-induced platelet aggregation in heparinised equine whole blood in vitro

Endotoxaemia is a leading cause of death among horses. Thrombocytopenia is a common finding in clinical and experimentally-induced cases of endotoxaemia and can lead to coagulopathies, including disseminated intravascular coagulopathy which is usually fatal. In this study it was shown that endotoxin (3 ng ml-1 to 25 micrograms ml-1) can aggregate equine platelets in heparinised whole blood in vitro. The endotoxin-induced aggregation (EIA) was shown to be dependent on the presence of leucocytes in the blood and did not occur when detoxified endotoxin was used, suggesting that lipid A was necessary for the response. Aspirin (1 mmol litre-1) had no effect on EIA whereas apyrase (40 micrograms ml-1) completely abolished it and CV3988 (3 to 30 mumol litre-1) (a competitive antagonist of platelet-activating factor) inhibited the response in a concentration-dependent manner. It is concluded that endotoxin activates equine platelets at low concentrations through an indirect mechanism that involves calcium, leucocytes, adenine nucleotides and platelet-activating factor.

Characterization of P2-purinoceptors in the smooth muscle of the rat tail artery: a comparison between contractile and electrophysiological responses

1. The electrophysiological actions of the P2-purinoceptor agonists, adenosine 5'-triphosphate (ATP), 2-methylthioATP (2-meSATP), alpha, beta-methyleneATP (alpha, beta-meATP) and uridine 5'-triphosphate (UTP) were studied under concentration and voltage-clamp conditions in acutely dissociated rat tail artery smooth muscle cells. For comparison, their actions as vasoconstrictors were studied in intact ring preparations. 2. Rapid application of ATP (100 nM-1 microM) via a U-tube superfusion system activated concentration-dependent inward currents with a latency to onset of less than 3 ms. The inward current decayed by more than 95% during a 2 s application of 300 nM and 1 microM ATP. 3. 2-meSATP (100 mM-1 microM) and alpha, beta-meATP (100 nM-1 microM) also evoked transient inward currents. The agonist order of potency was ATP = 2-meSATP > or = alpha, beta-meATP. UTP (300 nM-1 microM) did not produce a change in the holding current. 4. A second application of ATP (300 nM and 1 microM) 10 min after the first, evoked currents which were one third of the initial amplitude. This decline was dependent upon activation of the P2-purinoceptor. Similar results were seen with 2-meSATP and alpha, beta-meATP (both 300 nM and 1 microM). Cross-desensitization was seen between ATP and 2-meSATP or alpha, beta-meATP. 5. Inward currents evoked by ATP, 2-meSATP and alpha, beta-meATP (all 1 microM) were abolished by the P2-purinoceptor antagonist suramin (100 microM). 6. Alpha, beta-meATP (100 nM-30 micro M), 2-meSATP (3 micro M- 100 micro M), ATP (3 micro M-I mM) and UTP (3 ELM-I mM)produced concentration-dependent contractions of rat tail artery rings. When measured at a level equal to 50% of the maximum response to noradrenaline, the rank order of agonist potency was alpha,beta-meATP>>2-meSATP >UTP >ATP.7. This study shows that the rank order of agonist potency at the P2X-purinoceptor which mediates contractions of the rat isolated tail artery is very different from the potency order for evoking the inward current which initiates the contractions. It is concluded that this difference may be due to the relative absence of breakdown of some of the agonists in the single cell system compared with artery rings.

A new class of ligand-gated ion channel defined by P2x receptor for extracellular ATP

Extracellular ATP exerts its effects through P2 purinoceptors: these are ligand-gated ion channels (P2x) or G-protein-coupled receptors (P2Y, P2U). ATP at P2x receptors mediates synaptic transmission between neurons and from neurons to smooth muscle, being responsible, for example, for sympathetic vasoconstriction in small arteries and arterioles. We have now cloned a complementary DNA encoding the P2x receptor from rat vas deferens and expressed it in Xenopus oocytes and mammalian cells. ATP activates a cation-selective ion channel with relatively high calcium permeability. Structural predictions suggest that the protein (399 amino acids long) is mostly extracellular and contains only two transmembrane domains plus a pore-forming motif which resembles that of potassium channels. The P2x receptor thus defines a new family of ligand-gated ion channels.

The effects of aspirin and paracetamol on the aggregation of equine blood platelets

The responses of equine blood platelets in citrated platelet-rich plasma to arachidonic acid, U44069 (prostaglandin endoperoxide analogue), adenosine 5'-diphosphate, platelet-activating factor or collagen were investigated by turbidimetric aggregometry. Pre-treatment of the platelets with aspirin (1 mmol/l) or paracetamol (1.3 mmol/l) abolished shape change and aggregation in response to arachidonic acid; decreased the rate of aggregation in response to collagen, with no separate effect on shape change; had no marked effect on aggregation caused by the other agonists; but in no case transformed irreversible aggregation to reversible aggregation. We conclude that thromboxane A2 generation is of minor importance in the aggregation of equine platelets, and in particular that thromboxane A2 is not a significant mediator of irreversible aggregation.

Alexithymia in somatoform disorder patients with chronic pain

The prevalence of alexithymia in fifty-five motor vehicle accident survivors who had chronic pain complaints and met DSM-III-R criteria for somatoform pain disorder was 53%. Alexithymic and non-alexithymic patients did not differ on self-reports of current pain severity or in the number of pain locations. Alexithymic patients were found to use significantly more words to describe their pain, suggesting they may have a more diffuse style in communicating their pain experience.

X-ray structure of interleukin-1 receptor antagonist at 2.0-A resolution

Interleukin-1 receptor antagonist (IL-1ra) is a natural competitive antagonist of IL-1. In order to further elucidate the mechanism by which IL-1ra binds without activating the IL-1 receptor, we have solved the crystal structure of IL-1ra at 2.0-A resolution. IL-1ra has the same overall beta-trefoil fold as IL-1 alpha and IL-1 beta and has a very similar hydrophobic core. However, there are a number of structural differences between the molecules, including significant differences at the open end of the beta-barrel, which has been identified in IL-1 beta as a receptor binding site.

Morphological properties and projections of electrophysiologically characterized neurons in the guinea-pig submucosal plexus

Intracellular recordings were made from 73 guinea-pig submucosal neurons using neurobiotin-filled microelectrodes; subsequently, neuropeptide immunoreactivity, morphology and nerve fibre projections were determined. Five distinct groups of cells could be distinguished: S cells with inhibitory input (61%), S cells without inhibitory input (19%), AH cells (8%), S-AH cells (5%), and glial networks. S cells with inhibitory input were immunoreactive for vasoactive intestinal polypeptide and showed Dogiel Type III morphology with the axon branching and coursing through two to 12 ganglia; varicosities and tufts of varicosities were observed surrounding other cell bodies as well as over blood vessels. S cells without inhibitory input primarily were immunoreactive for neuropeptide Y; they also showed Dogiel Type III morphology and similar, though shorter, axonal projections and varicose features surrounding other neurons. AH cells, which most likely contained substance P, lacked synaptic input and exhibited Dogiel Type II morphology; they branched more extensively than S cells and also formed varicose tufts within other ganglia. S-AH cells combined electrophysiological properties of S cells with inhibitory input and AH cells and did not show consistent morphological or histochemical characteristics. Typical glial networks were observed; in addition, on two occasions unusual networks of dye and electrical coupling between S cells without inhibitory input and a glial complex were observed. These results suggest that vasoactive intestinal polypeptide-containing S cells may act as interneurons which mediate a slow excitatory synaptic potential; that neuropeptide Y-containing S cells, which are known to be cholinergic, may play a role as cholinergic interneurons mediating the nicotinic fast excitatory synaptic potential; and that AH neurons also may provide cholinergic innervation to other submucosal neurons in addition to their previously described dual projections into mucosa and myenteric plexus.

Stress fracture of the capitate

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Intraosseous infusion

Intraosseous infusion is recommended for children aged 6 years or less who have life-threatening conditions and require vascular access which cannot be achieved in a timely manner via another route. It is a reliable, safe procedure with a complication rate of less than 1%.

Intracranial haemorrhage associated with ingestion of 'ecstasy'

A case of a patient with intracranial haemorrhage thought to have been associated with ingestion of 'Ecstasy' [3-4 methylenedioxymethamphetamine (MDMA)] is presented. The case illustrates the importance of drug analysis in cases involving illicit drug use.

Induction of peri-insulitis but not diabetes in islet transplants expressing a single foreign antigen. A multi-stage model of disease

We have created a new transgenic model in which the human Epstein-Barr virus receptor, CR2 (CD21), has been expressed in pancreatic beta-cells. Mice derived from three transgenic founders bred into H-2b (C57BL/6) or H-2k (CBA) genetic backgrounds did not become spontaneously diabetic. After transplantation of CR2-expressing islets under the kidney capsule of genetically matched recipients, a histologic picture of peri-insulitis was found. However, animals did not manifest cellular invasion of the islets, destruction of the islets, or diabetes for at least 230 days. Significant numbers of both T and B lymphocytes were found in the cell population surrounding the islets. A pronounced serologic response to CR2 was also present and appeared to precede the onset of peri-insulitis. Thus, in this model, we have separated the process of diabetes induction into at least two phases. One is associated with peri-islet infiltration and an antibody response. However, at least one second signal is likely necessary for the process of islet destruction to follow.

Induction of peri-insulitis but not diabetes in islet transplants expressing a single foreign antigen. A multi-stage model of disease

We have created a new transgenic model in which the human Epstein-Barr virus receptor, CR2 (CD21), has been expressed in pancreatic beta-cells. Mice derived from three transgenic founders bred into H-2b (C57BL/6) or H-2k (CBA) genetic backgrounds did not become spontaneously diabetic. After transplantation of CR2-expressing islets under the kidney capsule of genetically matched recipients, a histologic picture of peri-insulitis was found. However, animals did not manifest cellular invasion of the islets, destruction of the islets, or diabetes for at least 230 days. Significant numbers of both T and B lymphocytes were found in the cell population surrounding the islets. A pronounced serologic response to CR2 was also present and appeared to precede the onset of peri-insulitis. Thus, in this model, we have separated the process of diabetes induction into at least two phases. One is associated with peri-islet infiltration and an antibody response. However, at least one second signal is likely necessary for the process of islet destruction to follow.

Effects of phospholipase A2 inhibitors on coupling of alpha 2-adrenoceptors to inwardly rectifying potassium currents in guinea-pig submucosal neurones

1. Noradrenaline hyperpolarizes guinea-pig submucosal neurones by opening inwardly rectifying potassium channels. Intracellular recordings were made from submucosal neurones and the possible involvement of the phospholipase A2 pathway in this response was examined. 2. The non-specific phospholipase A2 inhibitors, quinacrine (10 microM) and 4-bromophenacyl bromide (4-BPB, 10 microM) inhibited nerve-evoked inhibitory synaptic potentials (i.p.s.ps) and hyperpolarizations to somatostatin and UK 14304. Quinacrine and 4-BPB also blocked the inward rectification present in current-voltage curves in the absence of somatostatin or UK 14304. 3. The more selective phospholipase A2 inhibitor, cyclosporin A (10 microM) and the lipoxygenase and cyclo-oxygenase inhibitor, eicosatetraynoic acid (ETYA, 20 microM) and nordihydroguairetic acid (NDGA, 20 microM) did not alter i.p.s.ps or hyperpolarizations to UK 14304. 4. Exogenously applied arachidonic acid (1-300 microM) did not mimic the i.p.s.p. or the hyperpolarization to UK 14304. 5. We conclude that arachidonic acid or its eicosanoid metabolites produced by phospholipase A2 stimulation are unlikely to be involved in the receptor G-protein coupled activation of potassium currents in submucosal neurones. The inhibition of the noradrenaline-induced hyperpolarization by quinacrine and 4-BPB is most likely due primarily to blockade of the basal inwardly rectifying potassium conductance present in these neurones.

Telephone advice in the accident and emergency department: a survey of current practice

The objective of this study was to assess the standard of advice given by telephone by accident and emergency (A&E) departments following patients' enquiries. In order to do this patient enquiries were simulated and a telephone questionnaire was carried out. The study was carried out in 18 major and 16 minor A&E departments in Wales. Results achieved were that overall, correct telephone advice was given to 72 of 97 simulated patients (74%). Sixty calls were dealt with by the nursing staff (62%) who gave correct advice on 41 (68%) occasions. No A&E department had a formal policy nor provided staff training for handling patients' enquiries by telephone. It is concluded that A&E departments should train designated members of staff, preferably the triage nurse, who would formally deal with telephone enquiries requiring medical advice. There should be formal documentation of the enquiry and advice proffered as part of a departmental policy.