An update on the clinical pharmacology of kratom: uses, abuse potential, and future considerations

INTRODUCTION

Kratom (Mitragyna speciosa) has generated substantial clinical and scientific interest as a complex natural product. Its predominant alkaloid mitragynine and several stereoisomers have been studied for activity in opioid, adrenergic, and serotonin receptors. While awaiting clinical trial results, the pre-clinical evidence suggests a range of potential therapeutic applications for kratom with careful consideration of potential adverse effects.

AREAS COVERED

The focus of this review is on the pharmacology, pharmacokinetics, and potential drug-drug interactions of kratom and its individual alkaloids. A discussion on the clinical pharmacology and toxicology of kratom is followed by a summary of user surveys and the evolving concepts of tolerance, dependence, and withdrawal associated with kratom use disorder.

EXPERT OPINION

With the increasing use of kratom in clinical practice, clinicians should be aware of the potential benefits and adverse effects associated with kratom. While many patients may benefit from kratom use with few or no reported adverse effects, escalating dose and increased use frequency raise the risk for toxic events in the setting of polysubstance use or development of a use disorder.

Evaluating water quality benefits of manureshed management in the Susquehanna River Basin

Manureshed management guides the sustainable use of manure resources by matching areas of crop demand (nutrient sinks) with areas generating livestock manure (nutrient sources). A better understanding of the impacts of manureshed management on water quality within sensitive watersheds is needed. We quantified the potential water quality benefits of manureshed-oriented management through scenario-based analyses in the Susquehanna River Basin (SRB) using the Soil and Water Assessment Tool. Five manureshed management scenarios were developed and compared with a baseline "business-as-usual" scenario. The baseline assumes manure is less transportable, which means some locations have manure application in excess of crop demand. The "watershed nutrient balance" scenarios assume excess manure from surplus locations is transportable and that manure is applied around the SRB based on crop nutrient demand. The "watershed nutrient balance avoiding runoff prone areas" scenarios assume manure is transportable but not applied in vulnerable landscapes of the SRB. Each scenario was evaluated under two application rates considering crop nitrogen demand (N-based) and phosphorus demand (P-based). Phosphorus-based manureshed management was more effective in water quality improvements than N-based management. Phosphorus-based nutrient balance scenarios simulated 3 and 25% reduction in total N (TN) and total P (TP), respectively, from the baseline scenario at the watershed outlet. The N- and P-based scenarios avoiding runoff prone areas simulated 3 and 6% reduction in TN loss and 4 and 25.2% reduction in TP loss, respectively, from the baseline. Overall, the manureshed management scenarios were more effective in improving the quality of local streams in livestock-intensive regions than at the watershed outlet.

Efficacy and Safety of Hydroxychloroquine for Hospitalized COVID-19 Patients: A Systematic Review and Meta-Analysis

We systematically reviewed the efficacy and safety of hydroxychloroquine as treatment for hospitalized COVID-19. Randomized controlled trials (RCTs) evaluating hydroxychloroquine as treatment for hospitalized COVID-19 patients were searched until 2nd of December 2020. Primary outcomes were all-cause mortality, need of mechanical ventilation, need of non-invasive ventilation, ICU admission and oxygen support at 14 and 30 days. Secondary outcomes were clinical recovery and worsening, discharge, radiological progression of pneumonia, virologic clearance, serious adverse events (SAE) and adverse events. Inverse variance random effects meta-analyses were performed. Thirteen RCTs (n=18,540) were included. Hydroxychloroquine total doses ranged between 2000 and 12,400 mg; treatment durations were from 5 to 16 days and follow up times between 5 and 30 days. Compared to controls, hydroxychloroquine non-significantly increased mortality at 14 days (RR 1.07, 95%CI 0.92-1.25) or 30 days (RR 1.08, 95%CI 1.00-1.16). Hydroxychloroquine did not affect other primary or secondary outcomes, except SAEs that were significantly higher than the control (RR 1.24, 95%CI 1.05-1.46). Eleven RCTs had high or some concerns of bias. Subgroup analyses were consistent with main analyses. Hydroxychloroquine was not efficacious for treating hospitalized COVID-19 patients and caused more severe adverse events. Hydroxychloroquine should not be recommended as treatment for hospitalized COVID-19 patients.

Cover crop mixture expression is influenced by nitrogen availability and growing degree days

Cover crop mixtures can provide multiple ecosystem services but provisioning of these services is contingent upon the expression of component species in the mixture. From the same seed mixture, cover crop mixture expression varied greatly across farms and we hypothesized that this variation was correlated with soil inorganic nitrogen (N) concentrations and growing degree days. We measured fall and spring biomass of a standard five-species mixture of canola (Brassica napus L.), Austrian winter pea (Pisum sativum L), triticale (x Triticosecale Wittm.), red clover (Trifolium pratense L.) and crimson clover (Trifolium incarnatum L.) seeded at a research station and on 8 farms across Pennsylvania and New York in two consecutive years. At the research station, soil inorganic N (soil iN) availablity and cumulative fall growing degree days (GDD) were experimentally manipulated through fertilizer additions and planting date. Farmers seeded the standard mixture and a "farm-tuned" mixture of the same five species with component seeding rates adjusted to achieve farmer-desired services. We used Structural Equation Modeling to parse out the effects of soil iN and GDD on cover crop mixture expression. When soil iN and fall GDD were high, canola dominated the mixture, especially in the fall. Low soil iN favored legume species while a shorter growing season favored triticale. Changes in seeding rates influenced mixture composition in fall and spring but interacted with GDD to determine the final expression of the mixture. Our results show that when soil iN availability is high at the time of cover crop planting, highly competitive species can dominate mixtures which could potentially decrease services provided by other species, especially legumes. Early planting dates can exacerbate the dominance of aggressive species. Managers should choose cover crop species and seeding rates according to their soil iN and GDD to ensure the provision of desired services.

Salvaging the dehisced glans penis

OBJECTIVE

The glans penis may show a deep groove (surgically favorable), or may appear flat with an absent sulcus (unfavorable). Glans dehiscence following hypospadias repair, especially after multiple surgeries, frequently results in a scarred, obliterated, or absent urethral plate. The glans penis appears to be flat and grooveless. This study reported on the outcome of a two-stage salvage repair for glans dehiscence in 49 consecutive patients.

MATERIALS AND METHODS

Retrospective chart review was performed for all patients who underwent repair for glans dehiscence following hypospadias repair.

RESULTS

Between January 2009 and April 2015, 49 children aged 16 months to 18 years presented with glans dehiscence following hypospadias repair. The prior number of operations ranged from one to six. Eleven children had urethral fistulas, and seven had chordee. In the first stage, the flat glans was incised deeply to visualize, but spare, the corpora. Thereafter, a free graft of oral mucosa harvested either from the lower lip or cheek, or the residual preputial skin, was sutured to the glans cleft. The grafts were fenestrated, quilted in the midline, and a tie-over dressing was applied. Any fistula or chordee was repaired during the first stage. The neo-plate was tubularized 6-12 months later, and urine drainage with a catheter was maintained for 10-14 days. In 11 patients, skin flaps appeared dusky, and nitroglycerine ointment 2% was applied for 24 h to enhance the blood supply of the tissues. Subsequently, six of these children received nine or ten 90-min hyperbaric oxygen therapy sessions. Following the first stage, two patients developed hypertrophy of the mucosal grafts, and one skin graft contracted. These three patients underwent revision using a second buccal mucosal graft harvested from the cheek. One recurrent fistula was closed during the second stage. Following the second stage two patients developed a urethral fistula, and the distal sutures broke down in one patient, resulting in an over-sized meatus. None developed meatal stenosis or glans dehiscence.

CONCLUSION

Graft initial take and subsequent behavior were unpredictable, but the two stage approach optimized the process of take and healing. Glans dehiscence was repaired safely and successfully by developing a deep groove, with creation of a new urethral plate followed by tubularization in two stages.

Molecular fingerprinting of principal neurons in the rodent hippocampus: A neuroinformatics approach

Neurons are often classified by their morphological and molecular properties. The online knowledge base Hippocampome.org primarily defines neuron types from the rodent hippocampal formation based on their main neurotransmitter (glutamate or GABA) and the spatial distributions of their axons and dendrites. For each neuron type, this open-access resource reports any and all published information regarding the presence or absence of known molecular markers, including calcium-binding proteins, neuropeptides, receptors, channels, transcription factors, and other molecules of biomedical relevance. The resulting chemical profile is relatively sparse: even for the best studied neuron types, the expression or lack thereof of fewer than 70 molecules has been firmly established to date. The mouse genome-wide in situ hybridization mapping of the Allen Brain Atlas provides a wealth of data that, when appropriately analyzed, can substantially augment the molecular marker knowledge in Hippocampome.org. Here we focus on the principal cell layers of dentate gyrus (DG), CA3, CA2, and CA1, which together contain approximately 90% of hippocampal neurons. These four anatomical parcels are densely packed with somata of mostly excitatory projection neurons. Thus, gene expression data for those layers can be justifiably linked to the respective principal neuron types: granule cells in DG and pyramidal cells in CA3, CA2, and CA1. In order to enable consistent interpretation across genes and regions, we screened the whole-genome dataset against known molecular markers of those neuron types. The resulting threshold values allow over 6000 very-high confidence (>99.5%) expressed/not-expressed assignments, expanding the biochemical information content of Hippocampome.org more than five-fold. Many of these newly identified molecular markers are potential pharmacological targets for major neurological and psychiatric conditions. Furthermore, our approach yields reasonable expression/non-expression estimates for every single gene in each of these four neuron types with >90% average confidence, providing a considerably complete genetic characterization of hippocampal principal neurons.

A self-sustaining process model of inertial layer dynamics in high Reynolds number turbulent wall flows

Field observations and laboratory experiments suggest that at high Reynolds numbers Re the outer region of turbulent boundary layers self-organizes into quasi-uniform momentum zones (UMZs) separated by internal shear layers termed 'vortical fissures' (VFs). Motivated by this emergent structure, a conceptual model is proposed with dynamical components that collectively have the potential to generate a self-sustaining interaction between a single VF and adjacent UMZs. A large-Re asymptotic analysis of the governing incompressible Navier-Stokes equation is performed to derive reduced equation sets for the streamwise-averaged and streamwise-fluctuating flow within the VF and UMZs. The simplified equations reveal the dominant physics within-and isolate possible coupling mechanisms among-these different regions of the flow.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'.

A randomized trial testing the efficacy of modifications to the nutrition facts table on comprehension and use of nutrition information by adolescents and young adults in Canada

INTRODUCTION

Given the proposed changes to nutrition labelling in Canada and the dearth of research examining comprehension and use of nutrition facts tables (NFts) by adolescents and young adults, our objective was to experimentally test the efficacy of modifications to NFts on young Canadians' ability to interpret, compare and mathematically manipulate nutrition information in NFts on prepackaged food.

METHODS

An online survey was conducted among 2010 Canadians aged 16 to 24 years drawn from a consumer sample. Participants were randomized to view two NFts according to one of six experimental conditions, using a between-groups 2 x 3 factorial design: serving size (current NFt vs. standardized serving-sizes across similar products) x percent daily value (% DV) (current NFt vs. "low/med/high" descriptors vs. colour coding). The survey included seven performance tasks requiring participants to interpret, compare and mathematically manipulate nutrition information on NFts. Separate modified Poisson regression models were conducted for each of the three outcomes.

RESULTS

The ability to compare two similar products was significantly enhanced in NFt conditions that included standardized serving-sizes (p ≤ .001 for all). Adding descriptors or colour coding of % DV next to calories and nutrients on NFts significantly improved participants' ability to correctly interpret % DV information (p ≤ .001 for all). Providing both standardized serving-sizes and descriptors of % DV had a modest effect on participants' ability to mathematically manipulate nutrition information to calculate the nutrient content of multiple servings of a product (relative ratio = 1.19; 95% confidence limit: 1.04-1.37).

CONCLUSION

Standardizing serving-sizes and adding interpretive % DV information on NFts improved young Canadians' comprehension and use of nutrition information. Some caution should be exercised in generalizing these findings to all Canadian youth due to the sampling issues associated with the study population. Further research is needed to replicate this study in a more heterogeneous sample in Canada and across a range of food products and categories.

Efficacy and safety of antihyperglycaemic drug regimens added to metformin and sulphonylurea therapy in Type 2 diabetes: a network meta-analysis

AIM

To assess the efficacy and safety of third-line adjuvant antihyperglycaemic agents in people with Type 2 diabetes mellitus failing metformin and sulphonylurea combination therapy.

METHODS

We searched MEDLINE, CENTRAL, clinicaltrials.gov and regulatory websites, and conducted a manual search of references in the identified studies. Randomized trials evaluating antihyperglycaemic agents in adults with Type 2 diabetes experiencing poor glycaemic control despite optimized metformin and sulphonylurea therapy (≥ 1500 mg metformin or maximum tolerated dose; ≥ 50% of maximum sulphonylurea dose for ≥ 3 weeks) were included. Data extraction included: study characteristics; change in HbA1c concentration; weight; systolic blood pressure; and relative risk of hypoglycaemia, urinary tract infections; and genital tract infections. A network meta-analysis was performed.

RESULTS

A total of 20 trials evaluating 13 antihyperglycaemic agents were included. Compared with placebo/control, all antihyperglycaemic agents reduced HbA1c levels, albeit by differing magnitudes [range 7 mmol/mol (0.6%) for acarbose to 13 mmol/mol (1.20%) for liraglutide]. Sodium glucose cotransporter-2 inhibitors reduced weight (1.43-2.07 kg) whereas thiazolidinediones, glargine and sitagliptin caused weight gain (1.48-3.62 kg) compared with placebo/control. Sodium glucose cotransporter-2 inhibitors, rosiglitazone and liraglutide decreased systolic blood pressure compared with placebo/control, pioglitazone, glargine and sitagliptin (2.41-8.88 mm Hg). Glargine, thiazolidinediones, liraglutide, sitagliptin and canagliflozin increased hypoglycaemia risk compared with placebo/control (relative risk 1.92-7.47), while glargine and rosiglitazone increased hypoglycaemia compared with most antihyperglycaemic agents (relative risk 2.81-7.47). No antihyperglycaemic agent increased the risk of urinary tract infection, but canagliflozin increased the risk of genital tract infection by 3.9-fold compared with placebo/control.

CONCLUSIONS

When added to metformin and a sulphonylurea, antihyperglycaemic agents had varying effects on efficacy and safety endpoints. These conclusions should be considered when clinicians choose between possible adjunctive agents.

Does additional exercise improve trunk function recovery in stroke patients? A meta-analysis

BACKGROUND

The restoration of trunk function following stroke is a key component of rehabilitation, however there is limited evidence of the efficacy of additional trunk training.

OBJECTIVES

To evaluate the efficacy of trunk exercises added to conventional rehabilitation on functional outcomes.

METHODS

Relevant randomised controlled trials (RCTs), published up to July 2012, evaluating the effect of the addition of trunk exercises to conventional rehabilitation on functional outcomes were identified in Medline, Cinahl, Embase, Pubmed, PEDro, Web of Science and Scopus databases. Findings were summarised across studies as mean or standardised mean differences (MD or SMD) with 95% confidence intervals.

RESULTS

Six RCTs with 155 participants and a mean PEDro score of 6.5 (range 6 to 8) were included. Data from two to five studies were pooled in meta-analyses that showed a moderate, non-significant effect of additional trunk exercise on trunk performance, (SMD = 0.50; 95% CI -0.25, 1.25; P = 0.19); large effects on standing balance, SMD = 0.72 (95% CI -0.01, 1.45 P = 0.05); and walking ability, (SMD = 0.81; 95% CI 0.30, 1.33. P = 0.002) and a small, non-significant effect, MD = 10.03 (95% CI -15.70, 35.75. P = 0.44) on functional independence.

CONCLUSIONS

There is moderate evidence that the addition of specific trunk exercise to conventional early stroke rehabilitation significantly improve standing balance and mobility after stroke; however the evidence was weak for the effect of additional trunk exercise on trunk performance and in functional independence.

Improper disclosure: tobacco packaging and emission labelling regulations

OBJECTIVES

Cigarette packets in many countries display emission numbers such as tar. These numbers may be misleading as they do not represent the amount of toxins delivered to human smokers. This study examined how consumers interpret and understand numerical and descriptive emission information.

STUDY DESIGN

A discrete choice study was conducted among adult smokers (n = 312) and non-smokers (n = 291) in Ontario, Canada.

METHODS

Participants viewed groups of cigarette packets with emission labels from the European Union (EU), Canada and Australia. Participants completed ratings on perceived tar delivery, health risks, and usefulness and understandability of the information.

RESULTS

Participants were significantly more likely to believe that Canadian and EU packets with lower emission numbers would have lower tar delivery (92.2% and 89.9%, respectively) and lower health risks (89.5% and 82.9%, respectively) than packets with higher numbers. Approximately 74% of participants rated the numerical Canadian label as providing the most useful information; however, 62% also rated this label as most difficult to understand. Most participants rated the descriptive Australian label as easiest to understand.

CONCLUSIONS

Labels featuring quantitative emission values are associated with false beliefs regarding lower tar delivery and health risks. Descriptive statements about emissions are easier to understand and associated with more accurate beliefs.

Antiplatelet agents for the prevention of arteriovenous fistula and graft thrombosis: a meta analysis

AIMS

The aim of this study was to evaluate the impact of antiplatelet agents on the thrombosis rates of arteriovenous fistulae and grafts used for haemodialysis access.

METHODS

In this meta analysis, a systematic search of the literature was used to identify randomised controlled trials evaluating the effect of antiplatelet agents in graft or fistula thrombosis or bleeding. Two authors identified eligible trials and abstracted data on outcomes and study characteristics. The incidence of thrombosis was the primary outcome of interest and was calculated separately for studies evaluating grafts and those evaluating fistulae. A random-effects model was used for statistical pooling.

RESULTS

Ten trials were included in the analysis, nine of which reported outcomes on graft or fistula thrombosis. Antiplatelet agents reduced the rate of arteriovenous fistulae thrombosis (OR 0.54, 95% CI 0.31-0.94) but not grafts (OR 0.50, 95% CI 0.16-1.53). Both analyses had a moderate degree of statistical heterogeneity, likely because of differences in study design, antiplatelet agent and dose, as well as other possible factors. Review of bleeding events did not reveal a concerning risk of bleeding, but could not be statistically evaluated.

CONCLUSIONS

Antiplatelet agents reduce the rate of arteriovenous fistula thrombosis; however, at this time, research does not support the use of these agents for preventing arteriovenous graft thrombosis.

A prospective study of physiotherapist prescribed community based exercise in inflammatory peripheral neuropathy

There is insufficient evidence to support the use of exercise in the management of chronic disablement in people with inflammatory peripheral neuropathy. Therefore, our study aimed to determine the feasibility and effectiveness of a physiotherapist prescribed community based exercise programme for reducing chronic disablement in patients with stable motor neuropathy. We assessed the effects of a 12 week unsupervised, community based strengthening, aerobic and functional exercise programme on activity limitation and other measures of functioning in 16 people with stable motor neuropathy and 10 healthy control subjects. Fourteen of 16 patients and 8 out of 10 healthy control subjects completed the study and exercised safely in the community with no adverse events. Significant improvements were seen in all measures of activity limitation and in wider measures of health including anxiety, depression and fatigue in the patient group. Improvements were sustained at six months after completion of the exercise programme, except for depression. Ten patients continued to exercise regularly at six months. These findings demonstrate that individually prescribed community based exercise is feasible and acceptable for people with stable motor neuropathy and participation in exercise may be successful in reducing chronic disablement. Future randomised controlled trials are needed to examine the efficacy of this complex community based intervention.

The impact of gender on survival amongst patients with implantable cardioverter defibrillators for primary prevention against sudden cardiac death

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are a life-saving therapy for many patients with cardiovascular disease at increased risk of fatal dysrhythmias. As men comprise the majority of the study population (67-92%) in clinical trials, the benefit to women is unknown. We performed a meta-analysis of primary prevention trials to evaluate the impact of ICDs in men and women on death from any cause.

METHODS

Included trials met the following criteria: (i) randomized controlled trials versus standard of care, (ii) ICD used as primary prevention in a well-described protocol and (iii) data provided on risk of death from any cause for both male and female patients.

RESULTS

Five clinical trials were included in this meta-analysis. The risk of death from any cause was significantly reduced by 26% in male patients who received ICD therapy compared to control, hazard ratio (HR) 0.74 (95% CI 0.60-0.91) but not amongst female patients, HR 0.81 (95% CI 0.60-1.09). As the COMPANION trial evaluated the combination of biventricular pacemaker with ICD therapy we conducted a separate analysis without the inclusion of this study. Male patients receiving ICD therapy demonstrated a similar 24% reduction in risk of death from any cause, HR 0.76 (95% CI 0.58-0.99) whilst female patients demonstrated a reduction of only 12%, HR 0.88 (95% CI 0.63-1.22).

CONCLUSIONS

Unlike their male counterparts, females did not significantly benefit from ICD therapy and without concurrent biventricular pacing, appear only to achieve a nonsignificant 12% reduction in risk of death.

Exercise for people with peripheral neuropathy

BACKGROUND

Peripheral neuropathies are a wide range of diseases affecting the peripheral nerves. Demyelination or axonal degeneration gives rise to a variety of symptoms including reduced or altered sensation, pain, muscle weakness and fatigue. Secondary disability arises and this may result in adjustments to psychological and social function. Exercise therapy, with a view to developing strength and stamina, forms part of the treatment for people with peripheral neuropathy, particularly in the later stages of recovery from acute neuropathy and in chronic neuropathies.

OBJECTIVES

The primary objective was to examine the effect of exercise therapy on functional ability in the treatment of people with peripheral neuropathy. In addition, secondary outcomes of muscle strength, endurance, broader measures of health and well being, as well as unfavourable outcomes were examined.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group register (July 2002 and updated February 2004) and MEDLINE (from January 1966 to June 2004), EMBASE (from January 1980 to June 2004), CINAHL (from January 1982 to July 2002) and LILACS (from January 1982 to July 2002) electronic databases. Bibliographies of all selected randomised controlled trials were checked and authors contacted to identify additional published or unpublished data.

SELECTION CRITERIA

Any randomised or quasi-randomised controlled trial comparing the effect of exercise therapy with no exercise therapy or drugs or an alternative non-drug treatment on functional ability (or disability) in people with peripheral neuropathy at least eight weeks after randomisation was included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected eligible studies, rated the methodological quality and extracted data.

MAIN RESULTS

Only one trial fully met the inclusion criteria. An additional two trials assessed outcomes less than eight weeks after randomisation and were also included. Methodological quality was poor for several criteria in each study. Data used in the three studies could not be pooled due to heterogeneity of diagnostic groups and outcome measures. The results of the included trials failed to show any effect of strengthening and endurance exercise programmes on functional ability in people with peripheral neuropathy. However, there is some evidence that strengthening exercise programmes were moderately effective in increasing the strength of tested muscles.

REVIEWERS' CONCLUSIONS

There is inadequate evidence to evaluate the effect of exercise on functional ability in people with peripheral neuropathy. The results suggest that progressive resisted exercise may improve muscle strength in affected muscles.

CHARACTERIZATION OF THE HUMAN HEPATOCELLULAR CARCINOMA (HEPG2) CELL LINE AS AN IN VITRO MODEL FOR CADMIUM TOXICITY STUDIES

Biochemical indicators and in vitro models, if they mimic in vivo responses, offer potentially sensitive tools for inclusion in toxicity assessment programs. The purpose of this study was to determine whether the HepG2 cell line would mimic known in vivo or in vitro (or both) responses of mammalian systems when confronted with cadmium (Cd2+). Uptake and compartmentalization of Cd2+, metallothionein (MT) compartmentalization, and glutathione (GSH) depletion were examined. In addition, several cytotoxic and stress effects, e.g., viability (neutral red [NR] uptake, 3-[4,5-dimethylthiozole-2-yl]-2,5,-biphenyl tetrazolium bromide [MTT] dye conversion, and live/dead [L/D]), membrane damage (lactate dehydrogenase leakage), metabolic activity (adenosine triphosphate levels), and detoxification capabilities (GSH content, cytochrome P4501A1/2 [EROD (ethoxyresorufin-o-deethylase)] activity, and MT induction), were measured in both naive (no previous exposure) and Cd2+ preexposed cells. Cadmium uptake increased during a 24-h period. Metallothionein induction occurred in response to both Cd2+ and ZnCl2; however, Cd2+ was the more potent inducer. Both Cd2+ and MT were localized primarily in the cytoplasmic compartment. All biochemical responses, except EROD, showed concentration- response relationships, after 24-h exposure to Cd2+ (ranges 0-3 ppm [26.7 microM]). Cadmium effects were reduced in preexposed cells, indicating adaptive tolerance or increased resistance had occurred. Twenty-four-hour LC50, dose causing death of 50% of the test subjects, values were 0.97, 0.69, and 0.80 ppm (8.7, 6.2, and 7.2 microM) for naive cells and 1.45, 1.21, and 1.39 ppm (12.9, 10.7, and 12.3 microM) for preexposed cells based on the NR, MTT, and L/D assays, respectively. These data indicate that this carcinoma cell line is a useful in vitro model for cadmium toxicity studies.

Changes in P-wave dispersion and P-wave duration after open heart surgery are associated with the peak incidence of atrial fibrillation

BACKGROUND

Increased P-wave dispersion (P-disp) and maximum P-wave duration (P-max) predict the development of atrial fibrillation (AF) in the general population. The present study evaluates the time-dependent relationship of P-disp and P-max after open heart surgery.

METHODS AND RESULTS

P-disp and P-max were measured in the perioperative period of open heart surgery (one day before surgery through postoperative day 4). Compared with the baseline, P-max decreased immediately after open heart surgery (112.63 +/- 7.4 ms vs 106.9 +/- 8.2 ms, P =.005). An increase in P-disp was observed between postoperative days 1 and 2 (37.5 +/- 6.8 ms vs 43.1 +/- 4.5 ms, P <.05), and postoperative days 1 and 3 (37.5 +/- 6.8 ms vs 44.1 +/- 6.6 ms, P <.05). There was also an increase in the P-max between postoperative day 1 and 3 (103 +/- 8.3 ms vs 110 +/- 7.7 ms, P <.05).

CONCLUSIONS

Nonuniform atrial conduction (P-disp) is greatest on days 2 and 3 after open heart surgery, and the longest atrial conduction time (P-max) is greatest on day 3 after open heart surgery, findings that coincide with the time of greatest risk for AF. (Heart Lung((R)) 2001;30:466-71.)

A comparison of the QT and QTc dispersion among patients with sustained ventricular tachyarrhythmias and different etiologies of heart disease

OBJECTIVES

To determine if etiology of heart disease is associated with differences in QT and QTc dispersion among patients with ventricular tachyarrhythmias.

METHODS

This study was undertaken in 145 patients undergoing electrophysiological testing for sustained ventricular tachycardia or ventricular fibrillation. Patients were divided into groups based on etiology of heart disease determined by history, ECG, coronary angiography, and echocardiography. The groups included patients with: dilated cardiomyopathy (n = 29), myocardial infarction (n = 90), established coronary artery disease without a myocardial infarction (n = 11), or hypertension induced left ventricular hypertrophy (n = 15). The QT intervals on a 12--lead ECG were determined and Bazett's formula was used to derive the QTc intervals. The QT and QTc dispersion were determined by subtracting the shortest QT(c) interval from the longest on each 12-lead recording.

RESULTS

The patients with dilated cardiomyopathy had significantly higher QT and QTc dispersion values as compared to any of the other three groups (P < 0.05 for both). No other differences in electrocardiographic variables were found between groups.

CONCLUSIONS

In a group of patients with a history of ventricular tachycardia or ventricular fibrillation, QT and QTc dispersion are significantly greater among patients with dilated cardiomyopathy than for patients with a previous myocardial infarction, established coronary artery disease without a myocardial infarction, or hypertensive left ventricular hypertrophy.

Amiodarone in the new AHA guidelines for ventricular tachyarrhythmias

OBJECTIVE

To delineate amiodarone's role in the new American Heart Association guidelines for ventricular tachyarrhythmias, review the literature that supports the use of amiodarone in ventricular tachyarrhythmias, describe the pharmaceutical properties of amiodarone and elucidate their clinical implications, and discuss the dosing, preparation, and administration of amiodarone.

DATA SOURCES

A search of MEDLINE (1966-October 2000) database and EMBASE Drugs and Pharmacology database (1980-October 2000) was performed. References from published articles and tertiary references were used to gather additional data.

DATA EXTRACTION

All articles were screened, and pertinent studies were identified and evaluated.

DATA SYNTHESIS

Recent trials have demonstrated amiodarone's usefulness in the setting of ventricular tachyarrhythmias. Based on these investigations and contrary to past guidelines, amiodarone is included in the 2000 advanced cardiovascular life support guidelines as a possible agent for hemodynamically stable monomorphic ventricular tachycardia (VT), non-QT prolonged polymorphic VT, and ventricular fibrillation (VF)/pulseless VT. Although not specifically evaluated in the setting of hemodynamically stable monomorphic VT and non-QT prolonged polymorphic VT, investigations by the intravenous Amiodarone Multicenter Trial Group and other clinical trials make amiodarone an acceptable choice for these arrythmia categories. The results of the ARREST (Resuscitation of Refractory Sustained Ventricular Tachyarrhythmias) trial prove amiodarone to be the antiarrhythmic of choice for VF/pulseless VT.

CONCLUSIONS

Amiodarone is classified as a IIb therapeutic intervention for all three arrhythmia categories, which makes it an acceptable, safe, and useful agent with fair to good evidence to support its use. In addition, amiodarone requires careful preparation and delivery to achieve safe and effective outcomes.

Hematologic and chemical changes observed during and after cardiac arrest in a canine model--a pilot study

STUDY OBJECTIVE

To evaluate the effect of cardiac arrest and cardiopulmonary resuscitation (CPR) on blood chemistry in a canine model.

DESIGN

Evaluative canine animal study.

SETTING

Animal laboratory accredited by the Association for Assessment and Accreditation of Laboratory Animals.

SUBJECTS

Twenty-six adult mongrel dogs.

INTERVENTION

The dogs underwent an episode of induced fibrillatory cardiac arrest for 3 minutes followed by 10 minutes of standard CPR. Blood samples were taken at baseline (before cardiac arrest), after 10 minutes of ventricular fibrillation, and 10 minutes after successful resuscitation for determination of blood chemistries and hematologic parameters.

MEASUREMENTS AND MAIN RESULTS

Glucose, blood urea nitrogen, serum creatinine, sodium, potassium, chloride, calcium, phosphorus, uric acid, alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, protein, albumin, cholesterol, triglycerides, iron, white blood cell count, red blood cell count, and hematocrit were measured. Significant changes (p<0.05) in values obtained during CPR versus baseline values were noted for all laboratory parameters except blood urea nitrogen, chloride, and alkaline phosphatase. Eighteen dogs achieved return of spontaneous circulation (ROSC); their laboratory values were obtained after CPR. Significant changes (p<0.05) after ROSC compared with baseline were noted for all laboratory values except chloride, blood urea nitrogen, uric acid, alkaline phosphatase, glucose, potassium, calcium, triglycerides, iron, red blood cell count, and hematocrit.

CONCLUSION

Results indicate that significant changes in blood chemistries and hematologic parameters occur during and after CPR. Clinicians should note these normal laboratory parameter changes when interpreting laboratory data in patients who experience cardiac arrest.

Inhibition of transcription factor-DNA complexes and gene expression by a microgonotropen

Developing minor groove-binding drugs to selectively inhibit transcription factor (TF)/DNA interactions and accompanying gene expression is a current goal in drug development studies. Equipping minor groove-binding agents with positively charged, major groove-contacting side chains yields microgonotropens (MGTs). Previously, we demonstrated that MGTs were superior inhibitors of TF/DNA complexes in cell-free assays compared with "classical" groove binders, but MGTs showed limited ability to inhibit gene expression. To determine what chemical characteristics contribute to or improve activity, we evaluate five MGTs for their effectiveness in inhibiting TF complex formation and resultant transcription by using the c-fos serum response element (SRE) as a target. MGT L1 binds DNA via a bisbenzimidazole equipped with a tripyrrole moiety. It is compared with analog L2, which has been functionalized with propylamines on each of the three pyrroles. L2, which binds DNA at subpicomolar concentrations, was at least three orders of magnitude more potent than L1 at inhibiting TF binding to the c-fos SRE in cell-free assays. Unlike L1 and previous MGTs, L2 also inhibited endogenous c-fos expression in NIH 3T3 cells at micromolar levels. Structure/activity relationships suggest that, although the tripyrrole/polyamine functional group of L2 may be largely responsible for its inhibition of TF complexes in cell-free assays, its bisbenzimidazole moiety appears to impart improved cellular uptake and activity. These findings make L2 a promising lead candidate for future, rational MGT design.

Double-stranded DNA binding characteristics and subcellular distribution of a minor groove binding diphenyl ether bisbenzimidazole

The interactions of Hoechst 33377 (H1) with 20 different oligomeric duplexes have been investigated via spectrofluorometric titrations and/or thermal denaturation experiments. H1 is shown to form 2:1 complexes with dsDNA binding sites of at least four contiguous A/T base pairs. H1 is also shown to possess the rare ability to meaningfully distinguish between different A.T rich sequences. For example, the combined equilibrium constants for complexation of the oligomeric duplex 5'-GCAATTGC-3' (15) by H1 are found to be 110-fold greater than for the duplex 5'-GCTTAAGC-3' (16). It is believed that the 5'-TpA-3' dinucleotide step in 16 disrupts the rigid "A-tract" conformation of 15 and discourages minor groove binding by agents capable of recognizing longer dsDNA sequences. Molecular models are presented which elucidate the structure of the (H1)(2)-dsDNA minor groove complex. The two H1 molecules bind to an A/T rich sequence of 6 bp in a slightly staggered, side-by-side, and antiparallel arrangement. Evidence suggests that the piperazine rings of the H1 side-by-side complex are capable of resting in the minor groove of G/C base pairs. Fluorescence microscopy studies using NIH3T3 cells indicate that H1 is capable of traversing the cytoplasmic membrane and selectively localizing to nuclear DNA. H1 also demonstrated the ability to inhibit endogenous transcription of the c-fos gene in NIH3T3 cells at micromolar concentrations. Cytotoxicity studies employing the same cell type show H1 to possess an LD(50) of 3.5 microM.

Assessment of weight-based versus standard dosing of heparin in patients with unstable angina

OBJECTIVE

To assess whether a weight-based dosing regimen (80 u/kg + 18 u/kg/h) or a standard-fixed dose regimen (5000 u + 1000 u/h) of heparin is more appropriate in patients with unstable angina (UA).

METHOD

A drug use evaluation was conducted. Patient data for all patients weighing less than 100 kg who were in the coronary care unit of a Veterans Administration Hospital and who received heparin for UA (>24 h) over a 7-month period were included. For the first 4 months, patients were given standard heparin dosing and in the final 3 months patients were given heparin based on weight. The proportion of patients achieving activated partial thromboplastin times (aPTTs) that were at least therapeutic during therapy, the time to achieve the aPTT at a level that was at least therapeutic, and the number of patients with aPTTs over the therapeutic range were compared between groups.

RESULTS

Patients in the group receiving weight-based heparin therapy (n = 23) were significantly more likely to achieve an aPTT that was at least therapeutic than patients receiving standard therapy (n = 42, 100% vs. 76%, respectively, P = 0.011). When all the patients in each group who achieved an aPTT that was at least therapeutic were compared, the weight-based group achieved the levels significantly faster than the standard-fixed dosing group (7.3 +/- 6.1 vs. 22.6 +/- 17.6 h, respectively, P = 0.0003). However, the use of weight-based dosing was associated with a higher incidence of achieving supertherapeutic aPTTs than standard therapy (78.3% vs. 50.0%, respectively, P = 0.049).

CONCLUSION

Patients with UA may achieve therapeutic aPTTs faster than those on standard therapy but they also have a higher risk of achieving a supertherapeutic aPTT.

An evaluation of the change in electrocardiographic P-wave variables after acute caffeine ingestion in normal volunteers

BACKGROUND

Caffeine's effect on supraventricular dysrhythmias is poorly understood, and establishing a marker to predict atrial fibrillation may help to explain supraventricular dysrhythmias caused by caffeine.

OBJECTIVE

To evaluate the effects of caffeine (mean 6.1 mg/kg) on maximum P-wave duration and P-wave dispersion in normal volunteers.

METHOD

A randomised, double-blind, placebo-controlled, crossover study in 10 healthy volunteers at least 17 years of age at the University of Connecticut. Participants abstained from caffeinated products for at least 2 days before study initiation and were randomly allocated on different days to receive placebo or caffeine 400 mg. For each of the study phases, a baseline 12-lead electrocardiogram (ECG) was performed and a subsequent 12-lead ECG was performed 3 h after ingesting the study drug.

RESULTS

No significant changes were found within intra- or intergroup comparisons for any P-wave variables measured.

CONCLUSION

Single dose caffeine (400 mg) does not affect average P-wave duration, maximum P-wave duration or P-wave dispersion in normal individuals.

An evaluation of the hemostatic effects of hydrophilic, alcohol, and lipophilic extracts of notoginseng

STUDY OBJECTIVE

To compare the hemostatic effects of hydrophilic, alcohol, or lipophilic extract of notoginseng with those of the control and placebo.

DESIGN

Hemorrhagic rat model.

SETTING

Hartford Hospital, Hartford, Connecticut; animals were housed at the Hartford Hospital animal facility.

ANIMALS

Sixty-two male Wistar rats. Intervention. Administration of placebo (wheat flour), and alcohol, hydrophilic (water), and lipophilic (hexane) extracts of notoginseng.

METHODS

Rats were divided into five groups, and their tails were transected 5 mm from the tip. Group 1 received no treatment (control), group 2 received placebo, group 3 received alcohol extract, group 4 received hydrophilic extract, and group 5 received lipophilic extract. Total bleeding time was determined and compared among the groups.

MAIN RESULTS

Bleeding time was shorter for the placebo group than the control group (p=0.035). The alcohol extract group had the shortest bleeding time, which was significantly shorter than that of the control (p<0.0001), placebo (p=0.0124), and lipophilic extract groups (p=0.002). The hydrophilic extract group had a shorter bleeding time than the control group (p=0.0058) and showed a trend toward shorter bleeding time than the lipophilic extract group (p=0.068).

CONCLUSIONS

The alcohol extract of notoginseng results in the shortest bleeding time and provides better hemostatic effects than no treatment, placebo treatment, and treatment with lipophilic extract.

Pharmacokinetic comparison of omeprazole capsules and a simplified omeprazole suspension

The pharmacokinetics of omeprazole delayed-release capsules and a simplified omeprazole suspension (SOS) were studied. Seven healthy volunteers randomly received either one 20-mg omeprazole delayed-release capsule or SOS (omeprazole 20 mg in 10 mL) for seven days before being crossed over to the opposite treatment for seven more days after a two-week washout period. On days 1 and 7, blood samples were drawn at intervals up to 360 minutes after drug administration. Plasma omeprazole concentrations were determined by a validated high-performance liquid chromatographic method, and pharmacokinetic values were determined. Area under the concentration-versus-time curve (AUC) from zero to six hours, AUC from time zero to infinity (AUC0-infinity), and maximum plasma concentration (Cmax) increased by 102%, 113%, and 85%, respectively, after seven days of treatment with the capsule. AUC0-infinity for SOS on day 1 was 58% of that for the capsule (p = 0.0141), and on day 7 it was 49% of that for the capsule (p = 0.0044). AUC0-infinity for SOS increased by 85% from day 1 to 7, but the difference was not significant. Cmax for SOS on day 1 was twice that for the capsule (p = 0.0014), but by day 7 the difference between the two formulations was negligible. Time to Cmax (tmax) for SOS on days 1 and 7 was shorter than for the capsule by 82% (p < 0.0001) and 70% (p < 0.0006), respectively. After one week of therapy, omeprazole absorption was faster and tmax was 70% shorter for SOS than for the capsule formulation, but AUC0-infinity was 49% lower for SOS.

Evaluation of electrocardiographic and hemodynamic effects of caffeine with acute dosing in healthy volunteers

STUDY OBJECTIVE

To evaluate the effects of moderate, single-dose caffeine consumption on electrocardiographic variables: PR, QRS, QT, QTc, and RR intervals, and QT and QTc interval dispersion. Effects of caffeine on blood pressure and heart rate also were evaluated.

DESIGN

Randomized, double-blind, placebo-controlled, crossover study.

SETTING

University school of pharmacy.

PATIENTS

Ten healthy volunteers aged 17 years or older.

INTERVENTION

Participants abstained from caffeinated products for at least 2 days before the study began and were randomly designated to receive placebo or caffeine 400 mg on various days. For each of the study phases, a baseline 12-lead electrocardiogram (ECG) was performed and a subsequent 12-lead ECG performed 3 hours after ingesting the study drug. Blood pressure readings were taken with each ECG.

MEASUREMENTS AND MAIN RESULTS

No significant changes in any intragroup or intergroup electrocardiographic variables occurred. Caffeine increased blood pressure (systolic blood pressure [SBP]/diastolic blood pressure [DBP]) from 118+/-5/75+/-6 mm Hg to 128+/-8/77+/-7 mm Hg versus baseline (p=0.0022 and p=0.0368 for SBP and DBP, respectively). After drug dosing, SBP in the caffeine group was significantly higher than in the placebo group (128+/-8 mm Hg versus 119+/-7 mm Hg, p=0.0174).

CONCLUSION

Moderate caffeine consumption by healthy young adults does not acutely affect PR, QRS, QT, QTc, and RR intervals, or QT and QTc interval dispersion. Caffeine-naive subjects experienced persistent elevations in SBP and DBP 3 hours after caffeine ingestion, indicating that longer caffeine abstinence than that which is recommended is necessary for blood pressure determination in the clinical setting.

Evaluation of the antihyperlipidemic properties of dietary supplements

We reviewed the published literature regarding the antihyperlipidemic effects of dietary supplements. A search of MEDLINE database, EMBASE Drugs and Pharmacology database, and the Internet was performed, and pertinent studies were identified and evaluated. References from published articles and tertiary references were used to gather additional data. Published trials indicate that red yeast rice, tocotrienols, gugulipid, garlic, and soy protein all have antihypercholesterolemic effects. These supplements, as well as omega-3 fatty acids, also have antihypertriglyceridemic effects. In clinical trials none of the agents led to a reduction in low-density lipoproteins greater than 25%, suggesting modest efficacy. When recommending these supplements, clinicians should keep in mind that their long-term safety is not established and patients should be monitored closely.

Oral amiodarone for prevention of atrial fibrillation after open heart surgery, the Atrial Fibrillation Suppression Trial (AFIST): a randomised placebo-controlled trial

BACKGROUND

Beta-blockers and amiodarone reduce the frequency of atrial fibrillation after open-heart surgery but the effectiveness of oral amiodarone in older patients already receiving beta-blockers is unknown. We have assessed the efficacy of oral amiodarone in preventing atrial fibrillation in patients aged 60 years or older undergoing open-heart surgery.

METHODS

We did a randomised, double-blind placebo-controlled trial in which patients undergoing open-heart surgery (n=220, average age 73 years) received amiodarone (n=120) or placebo (n=100). Patients enrolled less than 5 days before surgery received 6 g of amiodarone or placebo over 6 days beginning on preoperative day 1. Patients enrolled at least 5 days before surgery received 7 g over 10 days beginning on preoperative day 5.

FINDINGS

Patients on amiodarone had a lower frequency of any atrial fibrillation (22.5% vs 38.0%; p=0.01; absolute difference 15.5% [95% CI 3.4-27.6%]), and there were significant differences in favour of the active drug for symptomatic atrial fibrillation (4.2% vs 18.0%, p=0.001), cerebrovascular accident (1.7% vs 7.0%, p=0.04), and postoperative ventricular tachycardia (1.7% vs 7.0%, p=0.04). Beta-blocker use (87.5% amiodarone vs 91.0% placebo), nausea (26.7% vs 16.0%), 30-day mortality (3.3% vs 4.0%), symptomatic bradycardia (7.5% vs 7.0%), and hypotension (14.2% vs 10.0%) were similar.

INTERPRETATION

Oral amiodarone prophylaxis in combination with beta-blockers prevents atrial fibrillation and symptomatic fibrillation and reduces the risk of cerebrovascular accidents and ventricular tachycardia.

Do HMG-CoA reductase inhibitors affect fibrinogen?

OBJECTIVE

To review commonly used fibrinogen assay methods and the evidence demonstrating an association between fibrinogen and increased risk of coronary artery disease and to review the current literature to determine and assess the impact of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on fibrinogen.

DATA SOURCES

Primary and review articles identified from a MEDLINE search (1966-December 1999); references obtained from these publications were subsequently reviewed for additional relevant articles.

STUDY SELECTION AND DATA EXTRACTION

All articles were evaluated, and all relevant information was included in this review.

DATA SYNTHESIS

The Clauss method is currently the preferred method for determining plasma fibrinogen concentrations, due to its high degree of accuracy and precision. Furthermore, unlike immunologic methods, its reliability is unaffected by change in triglycerides. The effects of four HMG-CoA reductase inhibitors (atorvastatin, lovastatin, simvastatin, pravastatin) on fibrinogen have been evaluated. Atorvastatin has been shown to induce significant increases in fibrinogen (22% increase; p <0.05) by using the immunonephelometric method. This method also demonstrated that lovastatin use was associated with a 24.4% increase (p < 0.0001) in plasma fibrinogen concentration. Simvastatin has been shown in multiple studies using the Clauss method to have a neutral effect on fibrinogen. The majority of studies have revealed significant decreases (7-19%) in fibrinogen following treatment with pravastatin.

CONCLUSIONS

Future studies need to be performed evaluating the effects of HMG-CoA reductase inhibitors on fibrinogen, but using direct comparisons and clotting assay methodology.

A placebo controlled evaluation of the antifibrillatory effects of carvedilol

This article evaluates the antifibrillatory effects of carvedilol 5 mg/kg and vehicle (dimethyl-formamide) over time. Sprague-Dawley rats were anesthetized and intubated. They underwent baseline ventricular fibrillation threshold (VFT) determination and then received 1 of the 2 treatments (n = 10/group) over 8 minutes. VFT and determinations were performed at 2, 7, 15, 30, 45, and 60 minutes postinfusion. Carvedilol significantly increased the VFT at 2, 7, 15, 30 minutes versus baseline and the vehicle control group. Carvedilol significantly reduced the heart rate and the mean arterial pressure at every evaluable time point versus baseline and vehicle control. Carvedilol showed significant antifibrillatory effects versus baseline and vehicle for the first 30 minutes but not thereafter, even though the heart rate and mean arterial pressure remain significantly reduced.

Evaluation of CYP2D6 oxidation of dextromethorphan and propafenone in a Chinese population with atrial fibrillation

The objective of this study was to determine the percentage of patients with paroxysmal atrial fibrillation who were poor metabolizers of CYP2D6 in a Chinese population from Hong Kong and to assess the relationship between the dextromethorphan/dextrorphan ratio and the propafenone/5-hydroxypropafenone ratio or the steady-state propafenone concentration. Patients (n = 60) were recruited from the Arrhythmia Clinic at the University of Hong Kong and given dextromethorphan 30 mg. The dextromethorphan and dextrorphan concentrations in urine over the next 8 hours were used to determine metabolizer status. If the metabolic ratio was greater than 0.3, the patient was determined to be a poor metabolizer. In phase 2, patients (n = 38) were given propafenone 150 mg twice daily, and at steady state, the propafenone and 5-OH propafenone plasma concentrations were determined. It was found that 15% of the patients were poor metabolizers of dextromethorphan. There was a significant correlation between the metabolic ratios of dextromethorphan/dextrorphan and propafenone/5-OH propafenone (r = 0.49, p = 0.0019) and between the dextromethorphan/dextrorphan ratio and the concentration of propafenone (r = 0.32, p = 0.05). No correlations were found in the extensive or poor metabolizer subgroups. It was concluded that the percentage of poor metabolizers in atrial fibrillation patients from Hong Kong was much larger than in previous studies of Chinese patients who were not from Hong Kong. The ability to metabolize dextromethorphan to dextrorphan is related to the ability to metabolize propafenone to 5-hydroxypropafenone.

The effect of testosterone on health-related quality of life in elderly males - a pilot study

OBJECTIVE

To assess the effect of short-term testosterone supplementation on health-related quality of life in elderly males.

METHOD

As part of a double-blind, placebo-controlled study, healthy males > or = 65-year-old were randomised to receive a total of four doses of 200 mg testosterone enanthanate (n = 14) or placebo (n = 8) intramuscularly every 2 weeks. Health-related quality of life (HRQOL) was assessed using the Short Form 36-item (SF-36) and Psychological General Well-Being (PGWB) scales, at baseline, week 8 and during therapy withdrawal, 6 weeks after the last dose.

RESULTS

The baseline SF-36 scores were similar between the groups in seven domains; only vitality was significantly lower in the placebo group (T: 80.4, P: 65.6; P = 0.007). After the 8-week treatment period and withdrawal phase, SF-36 scores were not significantly different between the groups. The PGWB scores at baseline, on treatment and off treatment were not significantly different between the groups. Moreover, the SF-36 and PGWB scores within each group did not change significantly over time.

CONCLUSION

This pilot study suggests that intramuscular testosterone, administered at a dose of 200 mg every 2 weeks, does not affect the HRQOL of elderly males.

Efficacy and cost analysis of ibutilide

OBJECTIVE

To determine the efficacy and safety of ibutilide in atrial fibrillation (AF) and atrial flutter (AFl) in a clinical setting and to compare the cost of first-line ibutilide with that of projected first-line electrical cardioversion (EC) from a hospital and third-party payer perspective.

METHODS

Medical records of all patients (n = 60) who received ibutilide from August 1996 to March 1998 were reviewed. Efficacy was defined as successful conversion to sinus rhythm within 60 minutes of the end of the infusion, and the maintenance of sinus rhythm until hospital discharge. Safety was evaluated by determining the incidence of torsade de pointes. Charges for EC and drug administration were obtained from the hospital database and converted to costs using cost/charge ratios. Hospital costs included drug, drug administration, cardiac intensive care laboratory fee, and the cost of managing torsade de pointes. The third-party payer calculation included all of the above plus the cardiologist and anesthesiologist fees.

RESULTS

Fifty percent of patients with AF or AFl were successfully converted with ibutilide; 67% of these remained in sinus rhythm at hospital discharge. Three patients experienced nonsustained torsade de pointes; all resolved with pharmacologic management. From a hospital perspective, the cost of first-line ibutilide was greater than the cost of first-line EC ($280 vs. $138 per patient). However, from a third-party payer perspective, the use of ibutilide saved approximately $324 per patient ($718 vs. $1042).

CONCLUSIONS

The efficacy and safety of ibutilide in the clinical setting are consistent with data reported in clinical trials. In contrast to a previous decision analysis, ibutilide was not associated with cost savings from a hospital perspective, but was from a payer perspective.

Effect of intravenous metoprolol or intravenous metoprolol plus glucagon on dobutamine-induced myocardial ischemia

STUDY OBJECTIVE

To determine the effect of metoprolol on dobutamine stress testing with technetium-99m sestamibi single-photon emission computed tomography imaging and ST-segment monitoring, and to assess the impact of intravenous glucagon on metoprolol's effects.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Community hospital.

PATIENTS

Twenty-two patients with known reversible perfusion defects.

INTERVENTION

Patients underwent dobutamine stress tests per standard protocol. Before dobutamine was begun, no therapy was given during the first visit, and patients were randomized on subsequent visits to receive metoprolol or metoprolol plus glucagon 1 mg. Metoprolol was dosed to achieve a resting predobutamine heart rate below 65 beats/minute or a total intravenous dose of 20 mg.

MEASUREMENTS AND MAIN RESULTS

Metoprolol reduced maximum heart rate 31%, summed stress scores 29%, and summed difference scores 43% versus control. Metoprolol plus glucagon also reduced the maximum heart rate 29% versus control. Summed stress and summed difference scores were not significantly reduced, although they were 18% and 30% lower, respectively, than control. No significant differences were found in any parameter between metoprolol and metoprolol-glucagon.

CONCLUSION

During dobutamine stress testing, metoprolol attenuates or eliminates evidence of myocardial ischemia. Glucagon 1 mg, although somewhat effective, does not correct this effect to the extent that it can be administered clinically.

Evaluation of the effectiveness of DNA-binding drugs to inhibit transcription using the c-fos serum response element as a target

Previous work has demonstrated that sequence-selective DNA-binding drugs can inhibit transcription factors from binding to their target sites on gene promoters. In this study, the potency and effectiveness of DNA-binding drugs to inhibit transcription were assessed using the c-fos promoter's serum response element (SRE) as a target. The drugs chosen for analysis included the minor groove binding agents chromomycin A(3) and Hoechst 33342, which bind to G/C-rich and A/T-rich regions, respectively, and the intercalating agent nogalamycin, which binds G/C-rich sequences in the major groove. The transcription factors targeted, Elk-1 and serum response factor (SRF), form a ternary complex (TC) on the SRE that is necessary and sufficient for induction of c-fos by serum. The drugs' abilities to prevent TC formation on the SRE in vitro were nogalamycin > Hoechst 33342 > chromomycin. Their potencies in inhibiting cell-free transcription and endogenous c-fos expression in NIH3T3 cells, however, were chromomycin > nogalamycin > Hoechst 33342. The latter order of potency was also obtained for the drugs' cytotoxicity and inhibition of general transcription as measured by [(3)H]uridine incorporation. These systematic analyses provide insight into how drug and transcription factor binding characteristics are related to drugs' effectiveness in inhibiting gene expression.

Angiotensin-converting-enzyme inhibition in heart failure or after myocardial infarction

The use of angiotensin-converting-enzyme (ACE) inhibitors in patients with heart failure and after myocardial infarction (MI) is discussed, and results of relevant studies are reviewed. In several large trials, the administration of captopril or lisinopril within the first 36 hours after the onset of chest pain due to MI was associated with significant reductions in mortality risk, compared with placebo. Trials evaluating the use of captopril, ramipril, or trandolapril at least three days after the onset of chest pain due to MI also demonstrated significant reductions in mortality risk. Pivotal clinical trials of captopril, enalapril, lisinopril, and ramipril in the treatment of heart failure are presented. Overall, ACE inhibitor therapy was shown to reduce mortality by decreasing the progression of heart failure. Possible benefits of ACE inhibition in addition to reductions in afterload and preload and preservation of serum potassium are discussed. Certain ACE inhibitors may exert positive effects by modulating plasminogen activator inhibitor-1, endothelial function, and left ventricular remodeling. If not contraindicated, long-term therapy with captopril, lisinopril, or ramipril should be used in post-MI patients. Patients with heart failure should be treated with one of the ACE inhibitors that have been shown beneficial for this indication.