Gas chromatographic-mass spectrometric assay for rocuronium with potential for quantifying its metabolite, 17-desacetylrocuronium, in human plasma

A rapid, sensitive and selective method has been developed for the quantification of plasma concentrations of neuromuscular blocking drug, rocuronium, using gas chromatography with mass spectrometric detection. 3-Desacetylvecuronium served as the internal standard. The method involved iodide ion pair formation and a single-step liquid-liquid extraction with dicholoromethane. This method also permits simultaneous determination of its putative metabolite, 17-desacetylrocuronium, although the high detection limit for the metabolite limits the practical application of this method in pharmacokinetic study of the metabolite. The extraction efficiency was approximately 75% for rocuronium and approximately 50% for 17-desacetylrocuronium. The limit of quantification was 26 ng/ml for rocuronium and 870 ng/ml for its metabolite. The assay was used successfully in a patient undergoing liver transplantation and receiving rocuronium as a constant rate infusion and in a patient undergoing general elective surgery receiving the drug as an intravenous bolus. This assay is a time-saving alternative to published gas or liquid chromatographic methods for assaying rocuronium.

Evaluation of the clinical efficacy of marbofloxacin (Zeniquin) tablets for the treatment of canine pyoderma: an open clinical trial

The efficacy and field safety of marbofloxacin (Zeniquin) for the treatment of superficial and deep bacterial pyoderma were evaluated. Seventy-two dogs were treated with 2.75 mg kg-1 of marbofloxacin orally once daily for 21 or 28 days. Sixty-two dogs (86%) had superficial pyoderma and 10 (14%) had deep pyoderma. A history of prior pyoderma was reported in 39/72 dogs. Pretreatment aerobic bacteriologic cultures of skin lesions were performed in 47 cases and the predominant pathogen isolated was Staphylococcus intermedius. Treatment was successful in 62/72 (86.1%) dogs, improvement was noted in 6/72 (8.3%) dogs and treatment failed in 4/72 (5.6%) dogs. Adverse effects associated with treatment included listlessness, anorexia, vomiting, soft stool, flatulence and polydipsia; these adverse effects were seen in only 6/81 dogs. Marbofloxacin was safe and effective for the treatment of superficial and deep pyoderma in dogs at the dosage used in this study.

Canopy level fluxes of 2-methyl-3-buten-2-ol, acetone, and methanol by a portable relaxed eddy accumulation system

Canopy level flux measurements of 2-methyl-3-buten-2-ol (MBO), acetone, and methanol were made over a subalpine forest in the Rocky Mountains in Colorado in the summer of 1999. The measurements were carried out using a portable relaxed eddy accumulation system that collected samples on adsorbent cartridges. Midday fluxes of acetone were highest at approximately 2.5 mg of C m-2 h-1. Methanol and MBO fluxes were approximately 1.0 mg of C m-2 h-1 each. These fluxes occurred with average daytime high temperatures of only 18 degrees C. Diurnal fluxes of MBO were strongly correlated with light and temperature. Acetone and methanol did not have simple diurnal patterns. These results indicate that oxygenated volatile organic compounds may make a significant contribution to the flux of reactive carbon to the atmosphere in western U.S. pine forests.

Influenza vaccination in pregnancy

The objective of this paper is to determine the acceptance rate of and incidence of adverse reactions to the influenza vaccine in pregnant women, and to determine the immunized patients' attitudes toward future vaccination. A total of 448 eligible pregnant women were offered the influenza vaccine at routine prenatal visits. Vaccinated women were interviewed at their subsequent visit regarding adverse effects and attitudes toward future vaccination. Of the 448 women studied, 319 (71.2%) accepted the vaccine. There was no difference in acceptance rates between English- and Spanish-speaking women. Mild adverse reactions were experienced by 5.3%. Women who reported adverse reactions were less likely to agree to future vaccination as compared with unaffected women (64.7 vs. 94.0% p < 0.001). The influenza vaccine is readily accepted by pregnant women, and is infrequently associated with mild side effects. Women who experience side effects are less likely to accept the vaccine in the future.

Anger expression, gender, and ambulatory blood pressure in mild, unmedicated adults with hypertension

The suppression of anger has been associated with the development of hypertension. This study evaluated the association between anger management style (anger-in and anger-out) and ambulatory blood pressure (ABP) in patients with repeated clinic diastolic blood pressures (DBPs) between 90-105 mmHg, unmedicated and with no known coronary artery disease. A total of 128 men (46.0 years) and 66 women (46.6 years) participated. Fourteen percent of men and 35% of women were classified as having "white coat" hypertension (daytime DBP < 85 mmHg). Mean awake and sleep DBP and systolic blood pressure (SBP) were evaluated in a repeated measures analysis of variance (ANOVA). Anger-in and anger-out scores were categorized into low, medium, and high t-scores (< 50, 50-59, > or = 60). Results indicated that in women, increasing anger-in is associated with greater SBPs while awake and sleeping, whereas no effect was found for DBP, nor any effect in men. No significant association was found between gender, anger-out, and ABP. The clinical diagnostic status of white coat hypertension was not differentially associated with anger-in or anger-out in men and women. In conclusion, in a sample of mild unmedicated adults with hypertension, suppression of anger is associated with greater ambulatory SBP in women, but not in men.

The rapid whole blood agglutination d-dimer assay has poor sensitivity for use as an exclusion test in suspected deep vein thrombosis

AIMS

Several clinical studies have proposed using d-dimer as an initial screening test to exclude thrombosis in cases of suspected (DVT). In published series, these assays have variable sensitivity, raising concerns that they may not be sufficiently robust for clinical practice. The aim of the study was to examine the sensitivity of two commercially available d-dimer assays and to assess their value and safety as initial screening tests in suspected DVT.

METHODS

In this prospective study, blood samples were collected for d-dimer measurement (SimpliRED assay and IL test d-dimer) in all patients presenting to the emergency department over a twelve month period. All patients underwent compression ultrasound scanning as the primary diagnostic procedure.

RESULTS

235 patients were included in the study. 51(22.8%) had a DVT confirmed on ultrasound. The SimpliRED assay was positive in only 33 cases, with seventeen cases of confirmed DVT giving a negative result (six cases with proximal vein thrombosis). Assay sensitivity was 66%, with a negative predictive value of 88.9%. The IL test gave three false negatives (all below knee thromboses) giving assay sensitivity and negative predictive value of 94.1% and 96.8% respectively.

CONCLUSIONS

The precise role of d-dimer testing in the diagnosis of venous thrombosis has yet to be established. From our results and a review of published series, we conclude that the SimpliRED assay is too insensitive to use as a reliable exclusion test in cases of suspected DVT, however, the more sensitive automated IL test d-dimer may have a role in the initial assessment. We propose that the IL d-dimer test is used in conjunction with a pre-test probability score to identify patients at low risk of DVT and recommend that this approach is tested in a clinical study before introduction into practice.

Sjogren's syndrome

Sjogren's syndrome is a chronic progressive autoimmune disorder manifested predominately by xerostomia (dry mouth) and keratoconjunctivitis sicca (dry eyes). It can also affect many body systems. Up to 5% of people over the age of 60 years have primary Sjogren's syndrome, and approximately one third of patients present with extraglandular (systemic) manifestations. This disease is seen mostly in middle-aged women, with a small but significant proportion of these women developing lymphoid neoplasia. The exact etiology is still unknown. This autoimmune disorder is characterized by B-cell activation, the production of numerous auto-antibodies, and the loss of immune tolerance. Salivary gland biopsy remains the most helpful diagnostic test. Treatment is aimed at moisture replacement, which alleviates the discomfort and slows the destructive process. Because of its prevalence in older women, the obstetrician-gynecologist must be aware of the diagnostic and therapeutic approach to Sjogren's syndrome.

The influence of marital adjustment on 3-year left ventricular mass and ambulatory blood pressure in mild hypertension

BACKGROUND

Of psychosocial stressors, job strain has been associated with a sustained increase in blood pressure. The impact of marital factors on blood pressure and target organ has not been explored.

OBJECTIVES

To evaluate whether marital adjustment, measured at baseline by self-report (Dyadic Adjustment Scale) influences left ventricular mass index (LVMI) and ambulatory blood pressure measured over 3 years in patients with mild hypertension.

METHODS

A prospective cohort study was conducted on 103 cohabiting males or females, including 72 with technically adequate echocardiograms, who at baseline were unmedicated, employed, and living with a significant other, all for a minimum of 6 months and had repeated elevated office diastolic blood pressure.

MAIN OUTCOME MEASURES

Left ventricular mass by M-mode echocardiography indexed to body surface area and blood pressure were measured by ambulatory blood pressure every 15 minutes (daytime) and hourly between 11 PM and 7 AM.

RESULTS

Marital adjustment, smoking, drinking, and baseline LVMI contributed significantly to the prediction of 3-year LVMI (semipartial correlation, sr(2) = 0.04, 0.07, 0.03, and 0.22; P =.03,.008,.08, and <.001, respectively) together accounting for 36% of the total variability in follow-up LVMI. Three-year ambulatory blood pressure measures were not significantly related to marital adjustment but there were correlations with Dyadic Adjustment Scale subscales. Low or high levels of spousal contact during 3-year ambulatory blood pressure monitoring were associated with an increase or decrease of 3-year, 24-hour diastolic blood pressure, consistent with the quality of marital adjustment (P =.04) or marital satisfaction (Dyadic Adjustment Scale subscale, P =.008).

CONCLUSIONS

In a cohort of subjects with mild essential hypertension, marital adjustment had an influence on 3-year LVMI. Depending on the quality of marital adjustment, spousal contact at 3 years was associated with an increase or decrease of 3-year diastolic blood pressure. Confirmation of these results, including objective marital assessment and the participation of normotensive subjects, is required. Arch Intern Med. 2000;160:3453-3458.

Neuromuscular paralysis as a pharmacodynamic probe to assess organ function during liver transplantation

Potential for assessing liver function during liver transplantation surgery by monitoring muscle paralysis from nondepolarizing neuromuscular blockers that are hepatically cleared is critically assessed. Rocuronium is strongly favored as a promising pharmacodynamic probe for predicting allograft liver function because it is predominantly eliminated via the liver and its putative metabolites are not active. Prolongation of recovery from rocuronium paralysis is closely correlated with allograft liver function postoperatively. Vecuronium, pancuronium, and perhaps pipecuronium may also prove to be useful probes, but the two former blockers have active metabolites. Further prospective studies are necessary with more precise measurement of neuromuscular function to confirm the predictive value of this method. Alterations in neuromuscular blocker plasma concentrations that are correlated with changes in liver function and either the dose required or the intensity or duration of paralysis needs to be demonstrated for this technique to be clinically useful.

Effectiveness of fluoxetine and doxepin in treatment of melancholia in depressed patients

It has been suggested that serotonin reuptake inhibitors (SSRIs) may be less effective than tricyclic antidepressants (TCAs) in treatment of melancholic depression. We treated 36 depressed ambulatory patients with doxepin or fluoxetine in a double-blind, randomized 6-week trial with placebo run-in. Seven patients treated with doxepin and 13 patients treated with fluoxetine met diagnostic criteria for melancholic depression. Average daily dose was 169.4 +/- 41.6 mg for doxepin and 36.8 +/- 18 mg for fluoxetine. We observed a 50% response rate in both treatment groups, using as outcome criterion reduction of Hamilton Depression Scale Score to less than 10. Regardless of how strict the definition of response, we found fluoxetine to be as effective as doxepin in our group of melancholic outpatients.

Depression and risk of sudden cardiac death after acute myocardial infarction: testing for the confounding effects of fatigue

OBJECTIVES

This study examined the impact of depressive symptoms and social support on 2-year sudden cardiac death (SCD) risk, controlling for fatigue symptoms.

METHODS

Myocardial infarction (MI) patients (N = 671) participating in the Canadian Amiodarone Myocardial Infarction Arrhythmia Trial completed measures of depression, hostility, and social support.

RESULTS

After controlling for significant biological predictors, psychosocial predictors of increased SCD risk in the survival analysis were greater social network contacts (RR = 1.04; 95% CI = 1.01-1.06; p < .007), lower social participation (RR = 0.98; 95% CI = 0.96-1.00; p < .05), and, in placebo-treated patients, elevated depressive symptoms (RR = 2.45; 95% CI = 1.14-5.35; p < .02). Fatigue was associated with SCD (RR = 1.31; 95% CI = 1.11-1.53; p < .001), and, when included in the model, diminished the influence of depression (RR = 1.73; 95% CI = 0.75-3.98; p = .20). When the cognitive-affective depressive symptoms were examined separately from somatic symptoms, there was a trend for an association between cognitive-affective symptoms and SCD in placebo-treated patients after controlling for fatigue (RR = 1.09; 95% CI = 0.99-1.19, p < .06).

CONCLUSIONS

Symptoms of depression and fatigue overlap in patients with MI. The trend for the cognitive-affective symptoms of depression to be associated with SCD risk, even after controlling for dyspnea/fatigue, suggests that the association between depression and mortality after AMI cannot be entirely explained as a confound of cardiac-related fatigue. The independent contribution of social participation suggests a role of both depressive symptomatology and social factors in influencing mortality risk after MI.

Distance estimates from paramagnetic enhancements of nuclear relaxation in linear and flexible model peptides

The distance dependence of electron-nuclear dipole-dipole coupling was tested using a series of poly-L-proline based peptides of different length. The poly-proline based peptides were synthesized with a nitroxide spin label on the N-terminus and a tryptophan on the C-terminus, and paramagnetic enhancements of nuclear spin-lattice relaxation rates were measured for the aromatic protons on the tryptophan as a function of the number of proline spacers in the sequence. As expected, paramagnetic enhancements decrease with distance, but the distances deduced from the NMR relaxation rates were shorter than expected for every peptide studied compared to a rigid linear poly-L-proline type II helix structure. Calculations of cross-relaxation rates indicate that this difference is not the result of spin-diffusion or the creation of a spin-temperature gradient in the proton spins caused by the nitroxide. Molecular dynamics simulations were used to estimate dynamically averaged value of <r(-3)>(2). These weighted average distances were close to the experimentally determined distances, and suggest that molecular motion may account for differences between the rigid linear models and the distances implied by the NMR relaxation data. A poly-L-prolone peptide synthesized with a central glycine hinge showed dramatic relaxation rate enhancements compared to the peptide of the same length lacking the hinge. Molecular dynamics simulations for the hinged peptide support the notion that the NMR data is a representation of the weighted average distance, which in this case is much shorter than that expected for an extended conformation. These results demonstrate that intermoment distances based on NMR relaxation rates provide a sensitive indicator of intramolecular motions.

Cost comparison of antibacterial therapies for serious infections. A New Zealand 3-hospital study

OBJECTIVE

The first aim was to identify and determine the economic costs of the regimens currently used in 3 New Zealand hospitals in the treatment of bacterial infections in haematology patients with febrile neutropenia and in intensive care patients with severe infections. The second was to develop a spreadsheet-based decision analytic model for use by hospital decision-makers as an aid in evaluating the comparative cost of drug regimens.

DESIGN AND SETTING

The research utilised time and motion and microcosting techniques. The analytical perspective adopted for the study was that of a hospital administrator or clinical manager.

PATIENTS AND INTERVENTIONS

Patients were eligible for inclusion in the study if either they were treated with the imipenem/cilastatin monotherapy, or could have been treated with this regimen. The final analysis considered 360 patient-treatment days and 8 antibacterials.

MAIN OUTCOME MEASURES AND RESULTS

Drug acquisition cost ranged from 4.52 New Zealand dollars ($NZ; 1997 values) per patient-treatment day for gentamicin to $NZ104.81 for imipenem. The cost per patient-treatment day (when other cost components such as fluid additives, giving sets and needles were added) ranged from $NZ8.75 for gentamicin to $NZ129.12 for tazobactam. Drug acquisition cost, as a percentage of total drug preparation and administration cost, ranged from 52% for gentamicin to 93% for piperacillin. Giving sets and intravenous (i.v.) fluids were found to be important cost items when they were required specifically for the treatment regimen. There was a mean monitoring rate of 0.40 at a cost of $NZ6.41 per patient-treatment day for gentamicin. It was estimated that nephrotoxicity could add between $NZ23 and $NZ43 per day to the cost of aminoglycoside treatment.

CONCLUSIONS

Although the small sample sizes of the study mean that results should be regarded as indicative rather than conclusive, there were sufficient information to construct a working model and show how the total cost of an antibacterial regimen could be evaluated in practical terms. The important cost drivers were found to be drug cost, the use of fluids and giving sets, and monitoring.

Poor adherence to placebo or amiodarone therapy predicts mortality: results from the CAMIAT study. Canadian Amiodarone Myocardial Infarction Arrhythmia Trial

OBJECTIVE

This study examined the relationship between adherence, mortality, and psychosocial factors.

METHODS

Subjects were 1141 patients participating in the Canadian Amiodarone Myocardial Infarction Arrhythmia Trial. Poor adherence to study medication (amiodarone or placebo), measured by pill count over 2 years, was defined as the lower 20th percentile of the pill count distribution. Predictors of adherence were also studied and included demographic and cardiac variables and, in a subset of participants (N = 671), measures of depression, distress, hostility, and social support.

RESULTS

In survival analysis controlling for cardiac and demographic variables, poor adherence in the placebo and amiodarone groups was associated with an increased risk of sudden cardiac death (relative risk (RR) = 2.11, 95% confidence interval (CI) = 1.03-4.56, p < .05; and RR = 3.15, 95% CI = 1.34-7.44, p < .01, respectively), total cardiac mortality (RR = 2.04, 95% CI = 1.12-3.72, p < .02; and RR = 2.49, 95% CI = 1.32-4.72, p < .01, respectively), and all-cause mortality (RR = 2.25, 95% CI = 1.27-3.97, p < .001; and RR = 2.34, 95% CI = 1.32-4.17, p < .004, respectively). Logistic regression analysis identified two predictors of poor adherence to placebo: age > 70 years (odds ratio = 2.18, 95% CI = 1.11-4.29, p < .03) and social activities in the month before the index heart attack (odds ratio = 1.02, 95% CI = 1.00-1.04, p < .05).

CONCLUSIONS

Poor adherence is associated with a greater risk of mortality. The relationship between adherence and social activities suggests a higher motivation to adhere to treatment in individuals more engaged in enjoyable activities.

An open-label preliminary trial of sertraline for treatment of major depression after acute myocardial infarction (the SADHAT Trial). Sertraline Anti-Depressant Heart Attack Trial

BACKGROUND

Depression occurs frequently in patients with acute myocardial infarction and is associated with increased mortality rates. It is not known whether serotonin reuptake inhibitors would be safe and effective for patients with depression after myocardial infarction and whether such treatment would reduce mortality rates.

METHODS AND RESULTS

We conducted a multicenter, open-label, pilot study of sertraline treatment in patients with major depressive disorder identified 5 to 30 days after admission for acute myocardial infarction. Outcome measures included cardiovascular and hemostatic function, adverse events, and mood ratings. Twenty-six patients were enrolled in the study. During treatment there were no significant changes in heart rate, blood pressure, cardiac conduction, or left ventricular ejection fraction, and there was a trend toward reduced ventricular ectopic activity. There were no changes in coagulation measures. Bleeding time increased in 12 patients, decreased in 4 patients, and was unchanged in 2 patients. Three (12%) patients withdrew from treatment prematurely because of adverse events. Significant improvements in mood ratings occurred over the course of treatment.

CONCLUSIONS

Sertraline treatment was associated with clinical improvement and was well tolerated in >85% of the patients in this open-label treatment trial for patients with major depression after myocardial infarction. These results encourage further controlled trials to establish the effects of treatment for this high-risk population.

Nocturnal and daytime panic attacks--comparison of sleep architecture, heart rate variability, and response to sodium lactate challenge

BACKGROUND

The purpose of this study was to determine if nocturnal panic patients have greater autonomic dysregulation than patients with daytime panic.

METHODS

Three groups were studied: patients who suffer from panic attacks during sleep (n = 12), those who suffer from daytime panic attacks only (n = 12), and control subjects (n = 12). Each subject underwent 24-hour holter monitoring for heart rate variability (HRV), an overnight sleep recording, and sodium lactate challenge during wakefulness.

RESULTS

There was a marked subjective response to the sodium lactate challenge in the panic disorder (PD) patients but not in control subjects. Each group showed changes in HRV in response to sodium lactate challenge. The decrease in HRV measures was more marked in PD patients as a whole than in control subjects. During non-rapid eye movement (REM) sleep the value for total power (TP) was significantly higher in the nocturnal panic patients. The PD patients as a whole had higher values for TP and low-frequency (LF) power during REM sleep than control subjects. There were no significant differences between the two PD groups in sleep architecture. The PD patients as a whole had lower sleep efficiency and less stage 4 sleep than control subjects.

CONCLUSIONS

These findings indicate that there are substantial differences between PD and control subjects in autonomic regulation and that there are small differences between patients with daytime panic attacks and those with sleep-related panic attacks.

The helicase domain of the TMV replicase proteins induces the N-mediated defence response in tobacco

Tobacco mosaic virus (TMV) induces the hypersensitive response (HR) in tobacco plants containing the N gene. This defence response is characterized by cell death at the site of virus infection and inhibition of viral replication and movement. A previous study indicated that a portion of the TMV replicase containing a putative helicase domain is involved in HR induction. Here, this observation is confirmed and extended by showing that non-viral expression of a 50 kDa TMV helicase fragment (p50) is sufficient to induce the N-mediated HR in tobacco. Like the HR elicited by TMV infection, transgenic expression of p50 induces a temperature-sensitive defence response. We demonstrate that recombinant p50 protein has ATPase activity, as suggested by the presence of conserved sequence motifs found in ATPase/helicase enzymes. A point mutation that alters one of these motifs abolishes ATPase activity in vitro but does not affect HR induction. These results suggest that features of the TMV helicase domain, independent of its enzymatic activity, are recognized by N-containing tobacco to induce TMV resistance.