Use of contaminated well water, example reference biospheres 1 and 2A.

The BIOMASS programme's Theme 1 evaluated a number of scenarios, which assisted in the development of practical guidance. A total of four Example Reference Biospheres were fully developed, with the assumptions, data, and models thoroughly documented. These Examples display both the practicality and the transparency available through the use of the Reference Biosphere Methodology. While the methodology is designed to promote transparency and traceability, proper documentation and justification is still the responsibility of the user. The Examples can also be used as generic analyses in some situations. Although it is anticipated that each of the Reference Biospheres explored within BIOMASS Theme 1 should be a useful practical example, the quantitative results of the model calculations are not intended to be understood as prescribed biosphere 'conversion factors'. In choosing to implement an Example, careful consideration would need to be given to their relevance (including associated data) to the particular assessment context at hand. In general, the more complex the model is, the more limited applicability it has for generic purposes. For example, ERB1A (direct use of well water for drinking) can be used straightforwardly, with minor or no adjustments, at a number of generic sites. Example 2A, however, for which climatic conditions and agricultural practices need to be specified, would need to be implemented for each specific situation.

Weather-dependent change of cesium, strontium, barium and tellurium contamination deposited as aerosols on various cultures.

Various types of plants (wheat, bean, lettuce, radish and grass) were contaminated by dry deposition of radioactive aerosols ((137)Cs, (85)Sr, (133)Ba and (123 m)Te) in order to supplement the radio-ecological data necessary for operational post-accidental codes. A few days after deposition, rainfalls were applied to these cultures to evaluate the influence of some characteristics of the rain on the contamination of the culture over time. On the other hand, for wheat and bean, the influence of the humidity condition of the foliage at the contamination time was considered. For a given plant species at a given vegetative stage, the four radionuclides were intercepted in an identical way. The interception varied from 30% for bean (young sprout) to 80% for lettuce (near maturity). The global transfer factor values were dependent on both the radionuclides and the plant species; nevertheless, a higher value was obtained for cesium, regardless of the plant and the rainfall (from 0.006 m(2)kg(fresh)(-1) for wheat-grains - contaminated at the shooting stage - or for bean-pods - contaminated at the pre-flowering stage - to 0.1m(2)kg(fresh)(-1) for a whole lettuce). The analysis of the results allowed us on the one hand, to extract parameter values of the foliar transfer directly usable in operational codes, in particular those relating to barium and tellurium, unknown until then, and on the other hand, to lay the foundations of a future, more mechanistic model, taking into account the foliar processes in a finer way.

Antiarrhythmic drug therapy in the Multicenter UnSustained Tachycardia Trial (MUSTT): drug testing and as-treated analysis.

OBJECTIVES: Using data from the Multicenter UnSustained Tachycardia Trial (MUSTT), we examined the factors used to select antiarrhythmic drug therapy and their impact on outcomes. BACKGROUND: The MUSTT examined the use of programmed ventricular stimulation (PVS) to guide antiarrhythmic therapy in patients with coronary arteriosclerosis, left ventricular dysfunction and asymptomatic, unsustained ventricular tachycardia (VT). Trial outcomes may reflect factors used to select antiarrhythmic drug therapy. METHODS: We compared subgroups of patients with inducible sustained VT randomized to PVS-guided antiarrhythmic therapy (n = 351), in particular those receiving PVS-guided antiarrhythmic drug therapy (n = 142) versus no antiarrhythmic therapy (controls, n = 353). RESULTS: "Effective" antiarrhythmic drug therapy (i.e., the term "effective" was used to denote therapy that resulted in noninducible VT or hemodynamically stable induced VT) was found for 142 of the 351 patients (43%), most often at the first or second PVS session (125/142, 88%). Mortality among the 142 patients did not differ from that among control patients. Of these 142 patients, the PVS end point was noninducibility in 91 patients and stable VT in 51 patients. Mortality did not differ between these two groups either, but arrhythmia was numerically more frequent in the PVS-induced stable VT group. Mortality was greatest in the few patients receiving propafenone (unadjusted p = 0.07, adjusted p = 0.14 vs. controls), but mortality with all agents did not differ from that of controls, even after adjustment. CONCLUSIONS: Even when presenting the results as favorably as possible, we found no benefit with PVS-guided drug therapy in patients with clinical unsustained VT who had inducible sustained VT. These findings are unaltered by using different end points for PVS or considering the response to individual drugs.

Biochemical characterization of the Pseudomonas aeruginosa 101/1477 metallo-beta-lactamase IMP-1 produced by Escherichia coli.

The blaIMP gene coding for the IMP-1 metallo-beta-lactamase produced by a Pseudomonas aeruginosa clinical isolate (isolate 101/1477) was overexpressed via a T7 expression system in Escherichia coli BL21 (DE3), and its product was purified to homogeneity with a final yield of 35 mg/liter of culture. The structural and functional properties of the enzyme purified from E. coli were identical to those of the enzyme produced by P. aeruginosa. The IMP-1 metallo-beta-lactamase exhibits a broad-spectrum activity profile that includes activity against penicillins, cephalosporins, cephamycins, oxacephamycins, and carbapenems. Only monobactams escape its action. The enzyme activity was inhibited by metal chelators, of which 1,10-o-phenanthroline and dipicolinic acid were the most efficient. Two zinc-binding sites were found. The zinc content of the P. aeruginosa 101/1477 metallo-beta-lactamase was not pH dependent.

Impact of rifampin on serum amiodarone concentrations in a patient with congenital heart disease.

A 33-year-old woman with congenital heart disease and atrial and ventricular arrhythmias, managed over the long term with an implantable cardioverter defibrillator, epicardial pacing system, and amiodarone, experienced an increase in palpitations and a shock from her defibrillator. Evaluation revealed decreases in amiodarone and desethylamiodarone serum concentrations from previous levels. Rifampin had been added to her therapy 5 weeks earlier. Increases in amiodarone and desethylamiodarone concentrations were observed after an increase in the amiodarone dosage and discontinuation of rifampin. The time course suggested that the addition of rifampin led to reductions in serum concentrations of both the drug and metabolite.

Dycal versus Nd:YAG laser and Vitrebond for direct pulp capping in permanent teeth.

PURPOSE: To determine the efficacy of laser-assisted direct pulp capping by comparing the survival rates of permanent teeth treated with Nd:YAG laser and Vitrebond (3M Corporation, St. Paul, MN) direct pulp caps to permanent teeth treated with the traditional calcium hydroxide direct pulp cap over intervals of up to 54 months. SUMMARY BACKGROUND DATA: While there are case reports and evaluations of various laser techniques in the literature, statistical studies comparing the success of laser-assisted applications to traditional techniques are needed. This is a retrospective investigation of one such laser assisted application. METHODS: A retrospective chart review of all active and inactive patients resulted in the identification of 83 patients who received direct pulp caps in a total of 93 permanent teeth; 29 with calcium hydroxide and 64 with Nd:YAG laser and Vitrebond. RESULTS: Life table analysis of the data of this retrospective study demonstrated that the teeth treated with the laser and Vitrebond direct pulp cap showed significantly greater survival rates than those treated with Dycal direct pulp cap over intervals of nine to 54 months postoperatively. The cumulative proportion of teeth surviving postoperatively for the Dycal (L.D. Caulk Corporation, Milford, CT) direct pulp cap was 89.7% at 1 month declining to 79.4% at 3 months and 76% at 6 months and then continued to decline in the final two intervals finishing after 54 months at 43.6%. For the laser and Vitrebond direct pulp cap the cumulative proportion surviving stood at 98.4% after 1 month, declining to 93.8% at 3 months and 90.3% after 6 months but then held steady in the final 2 intervals finishing at 90.3% after 54 months. CONCLUSION: The laser and Vitrebond direct pulp cap produces a significantly more predictable pulpal response after the first 6 months than the Dycal direct pulp cap. The survival rate of teeth treated with the laser and Vitrebond direct pulp cap is significantly greater than those treated with the Dycal direct pulp cap over intervals of 9 to 54 months. Direct pulp capping is a worthwhile procedure that should be performed when indicated, especially in light of the 90.3% survival rate achieved with the laser and Vitrebond direct pulp cap at 54 months.

Ventricular output failure in a DDD permanent pacemaker associated with increased atrial output.

Previous reports have described the occurrence of ventricular output failure in a permanent DDD pacemaker system related to an increase in the atrial output in the presence of low atrial lead impedance (Medtronic Synergyst/Synergyst II). This phenomenon is seen exclusively following atrial paced events and may potentially lead to significant bradyarrhythmia or ventricular asystole in a pacemaker dependent patient. We describe the occurrence of analogous behavior in a Medtronic Symbios 7006 generator.

Parent participation in the postanesthesia care unit: fourteen years of progress at one hospital.

Parent participation in postanesthesia nursing practice was instituted in 1983 at Boston's Children's Hospital as part of a continuing emphasis on family participation in the care of hospitalized children throughout the hospital. This report describes the evolution and implementation of this practice. The success of this program is supported by data from quality improvement monitors of the comfort levels of PACU patients before and after their parents were invited to the bedside. Quality improvement monitors of parent satisfaction with involvement in their child's care were also conducted. Nursing exemplars illustrate parental and nursing responses to this program.

Ventricular output failure in a DDD permanent pacemaker associated with increased atrial output.

Previous reports have described the occurrence of ventricular output failure in a permanent DDD pacemaker system related to an increase in the atrial output in the presence of low atrial lead impedance (Medtronic Synergyst/Synergyst II). This phenomenon is seen exclusively following atrial paced events, and may potentially lead to significant bradyarrhythmia or ventricular asystole in a pacemaker dependent patient. We describe the occurrence of analogous behavior in a Medtronic Symbios 7006 generator.

Modification of cardiac Na+ channels by batrachotoxin: effects on gating, kinetics, and local anesthetic binding.

The purpose of the present study was to examine the characteristics of Na+ channel modification by batrachotoxin (BTX) in cardiac cells, including changes in channel gating and kinetics as well as susceptibility to block by local anesthetic agents. We used the whole cell configuration of the patch clamp technique to measure Na+ current in guinea pig myocytes. Extracellular Na+ concentration and temperature were lowered (5-10 mM, 17 degrees C) in order to maintain good voltage control. Our results demonstrated that 1) BTX modifies cardiac INa, causing a substantial steady-state (noninactivating) component of INa, 2) modification of cardiac Na+ channels by BTX shifts activation to more negative potentials and reduces both maximal gNa and selectivity for Na+; 3) binding of BTX to its receptor in the cardiac Na+ channel reduces the affinity of local anesthetics for their binding site; and 4) BTX-modified channels show use-dependent block by local anesthetics. The reduced blocking potency of local anesthetics for BTX-modified Na+ channels probably results from an allosteric interaction between BTX and local anesthetics for their respective binding sites in the Na+ channel. Our observations that use-dependent block by local anesthetics persists in BTX-modified Na+ channels suggest that this form of extra block can occur in the virtual absence of the inactivated state. Thus, the development of use-dependent block appears to rely primarily on local anesthetic binding to activated Na+ channels under these conditions.