Contributions from Caenorhabditis elegans functional genetics to antiparasitic drug target identification and validation: nicotinic acetylcholine receptors, a case study.

Following the complete sequencing of the genome of the free-living nematode, Caenorhabditis elegans, in 1998, rapid advances have been made in assigning functions to many genes. Forward and reverse genetics have been used to identify novel components of synaptic transmission as well as determine the key components of antiparasitic drug targets. The nicotinic acetylcholine receptors (nAChRs) are prototypical ligand-gated ion channels. The functions of these transmembrane proteins and the roles of the different members of their extensive subunit families are increasingly well characterised. The simple nervous system of C. elegans possesses one of the largest nicotinic acetylcholine receptor gene families known for any organism and a combination of genetic, microarray, physiological and reporter gene expression studies have added greatly to our understanding of the components of nematode muscle and neuronal nAChR subtypes. Chemistry-to-gene screens have identified five subunits that are components of nAChRs sensitive to the antiparasitic drug, levamisole. A novel, validated target acting downstream of the levamisole-sensitive nAChR has also been identified in such screens. Physiology and molecular biology studies on nAChRs of parasitic nematodes have also identified levamisole-sensitive and insensitive subtypes and further subdivisions are under investigation.

Tuberculosis control and molecular epidemiology in a South African gold-mining community.

BACKGROUND: Gold miners have very high rates of tuberculosis. The contribution of infections imported into mining communities versus transmission within them is not known and has implications for control strategies. METHODS: We did a prospective, population-based molecular and conventional epidemiological study of pulmonary tuberculosis in a group of goldminers. Clusters were defined as groups of patients with Mycobacterium tuberculosis isolates with identical IS6110 DNA fingerprints. We compared the frequency of possible risk factors in the clustered and non-clustered patients whose isolates had fingerprints with more than four bands, and re-interviewed members of 45 clusters. FINDINGS: Of 448 patients, ten were excluded because they had false-positive cultures. Fingerprints were made in 419 of 438, of which 371 had more than four bands. 248 of 371 were categorised into 62 clusters. At least 50% of tuberculosis cases were due to transmission within the community. Patients who had failed treatment at entry to the study were more likely to be in clusters (adjusted odds ratio 3.41 [95% CI 1.25-9.27]). Patients with multidrug-resistant isolates were more likely to have failed treatment but were less likely to be clustered than those with a sensitive strain (0.27 [0.09-0.83]). HIV infection was common (177 of 370 tested) but not associated with clustering. INTERPRETATION: Despite a control programme that cures 86% of new cases, most tuberculosis in this mining community is due to ongoing transmission. Persistently infectious individuals who have previously failed treatment may be responsible for one third of tuberculosis cases. WHO targets for cure rates are not sufficient to interrupt transmission of tuberculosis in this setting. Indicators that are more closely linked to the rate of ongoing transmission are needed.

Care coordinator--blending roles to improve patient outcomes.

A care coordinator blends aspects of the case manager and clinical specialist roles with those of a unit-based staff developer. In this position, the nurse facilitates critical pathways; coordinates care with the patient, family, ancillary staff and community services; delivers unit-based staff-development programs; and acts as mentor, staff resource person and physician liaison. The development and utilization of this professional nursing role in a community hospital is outlined.

Refining the treatment of women with unstable angina--a randomized, double-blind, comparative safety and efficacy evaluation of Integrelin versus aspirin in the management of unstable angina.

BACKGROUND: Although women typically develop coronary artery disease several years after men, once they have symptomatic disease their thromboembolic complications are worse than in men. The mechanism mediating this gender difference in outcome after thromboembolic events is unknown. We previously studied platelet functions in siblings from patients with premature coronary artery disease. We observed that platelets from women are responsive than their male counterparts. In particular, platelets from women stimulated ex vivo with various agonists bind more fibrinogen molecules than platelets from men. HYPOTHESIS: We hypothesized that in patients with acute coronary events, the control of platelet activity might require stronger antagonists in women than in men. METHODS: To test this hypothesis, we investigated retrospectively the results of a trial on Integrelin in unstable angina. RESULTS: We report that platelet aggregation and Holter-detected ischemic episodes are significantly reduced in women with unstable angina treated with the specific GPIIb-IIIa inhibitor, Integrelin, compared with the standard platelet inhibitor aspirin. In contrast, both platelet aggregation and Holter-detected ischemic events are well controlled in men with unstable angina treated with standard therapy including aspirin. CONCLUSION: Integrelin does provide protection in men, but, in contrast with women, not beyond what can be achieved with aspirin. Our data are consistent with the concept that the platelets from women require stronger and more specific inhibitors to limit their activity, and that platelets may play a more important role in women with acute coronary syndromes than in men. Most important, specific GPIIb-IIIa inhibitors may represent a therapeutic option which provides as much suppression of ischemic events in women as they do in men with coronary artery disease.

Effects of integrelin, a platelet glycoprotein IIb/IIIa receptor antagonist, in unstable angina. A randomized multicenter trial.

BACKGROUND: Although aspirin is beneficial in patients with unstable angina, it is a relatively weak inhibitor of platelet aggregation. The effect of Integrelin, which inhibits the platelet fibrinogen receptor glycoprotein (GP) IIb/IIIa, on the frequency and duration of Holter ischemia was evaluated in 227 patients with unstable angina. METHODS AND RESULTS: Patients received intravenous heparin and standard ischemic therapy and were randomized to receive oral aspirin and placebo Integrelin; placebo aspirin and low-dose Integrelin. 45 micrograms/kg bolus followed by a 0.5 microgram.kg-1. min-1 continuous infusion; or placebo aspirin and high-dose Integrelin, 90 micrograms/kg bolus followed by a 1.0-microgram.kg-1, min-1 constant infusion. Study drug was continued for 24 to 72 hours, and Holter monitoring was performed. Patients randomized to high-dose Integrelin experienced 0.24 +/- 0.11 ischemic episodes (mean +/- SEM) on Holter lasting 8.41 +/- 5.29 minutes over 24 hours of study drug infusion. Patients randomized to aspirin experienced a greater number (1.0 +/- 0.33, P < .05) and longer duration (26.2 +/- 9.8 minutes, P = .01) of ischemic episodes than the high-dose Integrelin group. There was no evidence of rebound ischemia after withdrawal of study drug. In 46 patients, platelet aggregation was rapidly inhibited by Integrelin in a dose-dependent fashion. The number of clinical events was small, and there were no bleeding differences in the three treatment arms. CONCLUSIONS: Intravenous Integrelin is well tolerated, is a potent reversible inhibitor of platelet aggregation, and added to full-dose heparin reduces the number and duration of Holter ischemic events in patients with unstable angina compared with aspirin.

MERG: medication event rating grid.

Through a four-step process, a medication event rating grid (MERG) tracks medication errors. An educational and a remedial plan are included to help individual staff members develop strategies to prevent future errors.

Stability and activity of alteplase with injectable drugs commonly used in cardiac therapy.

The stability, activity, and compatibility of alteplase with eight drugs frequently used in cardiovascular disease were studied. Alteplase 1 mg/mL was mixed with each of the following: heparin sodium 80 units/mL in 0.9% sodium chloride injection, dobutamine 10 mg/mL (as the hydrochloride salt) in 0.9% sodium chloride injection or 5% dextrose injection, dopamine hydrochloride 1.6 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection, morphine sulfate 2 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection, lidocaine hydrochloride 8 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection, propranolol hydrochloride 1 mg/mL, metoprolol tartrate 1 mg/mL, or nitroglycerin 0.8 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection. Each mixture was assayed immediately and after storage for 24 hours at 25 degrees C; mixtures containing heparin were also assayed at 4 hours. The alteplase concentration and percentage of the single-chain molecule in each mixture were analyzed by using size-exclusion high-performance liquid chromatography (HPLC). Alteplase bioactivity was determined by a clot-lysis assay. Drug concentrations were assayed by HPLC, pH values of the mixtures were determined, and the mixtures were visually inspected. Instability was defined as a > 10% decrease in concentration; inactivity was defined as a > 10% decrease in activity; incompatibility was defined as detection of a precipitate, opalescence, or color change. Alteplase was not stable in the presence of heparin sodium, morphine sulfate, or dobutamine and was not active in the presence of dopamine hydrochloride. Alteplase was compatible with and stable and active (in vitro) in the presence of lidocaine hydrochloride, propranolol hydrochloride, metoprolol tartrate, or nitroglycerin.(ABSTRACT TRUNCATED AT 250 WORDS)