The Design of an Adaptive Clinical Trial to Evaluate the Efficacy of Extra-Corporeal Membrane Oxygenation for Out-of-Hospital Cardiac Arrest

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR) is a promising therapy for out-of-hospital cardiac arrest (OHCA) that is refractory to standard therapy, but no multicenter randomized clinical trials have been conducted to establish its efficacy. We report the design and operating characteristics of a proposed randomized Bayesian adaptive "enrichment" clinical trial designed to determine whether ECPR is effective for refractory OHCA and, if effective, to define the interval after arrest during which patients derive benefit.

METHODS

Through iterative trial simulation and trial design modification, we developed a Bayesian adaptive trial of ECPR for adults who experience non-traumatic out-of-hospital cardiac arrest. Our proposed trial design addresses the threats to trial success identified during the design process, which were (1) the uncertainty surrounding the cardiac arrest (CA)-to-ECPR interval within which clinical benefit might be preserved (2) the difference in prognosis between patients with an initial rhythm that is non-shockable vs. shockable. Trial subjects will be randomized 1:1 to receive either standard care or expedited transport to a hospital for potential ECPR. The CA-to-ECPR interval will be estimated in real time based on the sum of the estimated paramedic response time (911 call to scene arrival), paramedic scene time, and transport time to hospital. A Bayesian decreasing step function will be used to estimate the efficacy of the treatment with an outcome of the 90-day utility-weighted Modified Rankin Scale (uwmRS) for each rhythm subgroup and estimated CA-to-ECPR interval at pre-specified interims. The trial will adaptively lengthen the estimated CA-to-ECPR eligibility window if the treatment appears effective at the upper limit of initial eligibility window. If ECPR appears ineffective at longer estimated CA-to-ECPR intervals, the upper limit of the window for enrollment eligibility will be shortened. The analysis will be stratified by rhythm subgroup.

RESULTS

With a maximum total sample size of 400, and a cap on the maximum sample size of 300 for the non-shockable rhythm subgroup, the trial design has power ranging from 91-100% to detect a benefit from ECPR for non-shockable rhythms under the various efficacy scenarios simulated and power ranging from 69-98% for shockable rhythms under the same scenarios. The trial design also has a high probability of correctly identifying the maximum CA-to-ECPR interval within which ECPR produces a clinically significant benefit of 0.2 on the uwMRS. If ECPR is equivalent to standard CA care, the type I error is 2.5% with a 99% probability of stopping enrollment early for futility in the non-shockable subgroup and a 97% probability of stopping enrollment early for futility in the shockable subgroup.

CONCLUSION

This proposed adaptive trial design helps to ensure the population of patients who are most likely to benefit from treatment-as defined both by rhythm subgroup and estimated CA-to-ECPR interval-is enrolled. The design promotes early termination of the trial if continuation is likely to be futile.

A platform in the use of medicines to treat chronic hepatitis C (PLATINUM C): protocol for a prospective treatment registry of real-world outcomes for hepatitis C

Background

Safe, highly curative, short course, direct acting antiviral (DAA) therapies are now available to treat chronic hepatitis C. DAA therapy is freely available to all adults chronically infected with the hepatitis C virus (HCV) in Australia. If left untreated, hepatitis C may lead to progressive hepatic fibrosis, cirrhosis and hepatocellular carcinoma. Australia is committed to eliminating hepatitis as a public health threat by 2030 set by the World Health Organization. However, since the introduction of funded DAA treatment, uptake has been suboptimal. Australia needs improved strategies for testing, treatment uptake and treatment completion to address the persisting hepatitis C public health problem. PLATINUM C is a HCV treatment registry and research platform for assessing the comparative effectiveness of alternative interventions for achieving virological cure.

Methods

PLATINUM C will prospectively enrol people with active HCV infection confirmed by recent detection of HCV ribonucleic acid (RNA) in blood. Those enrolled will agree to allow standardised collection of demographic, lifestyle, treatment, virological outcome and other relevant clinical data to better inform the future management of HCV infection. The primary outcome is virological cure evidenced by sustained virological response (SVR), which is defined as a negative HCV PCR result 6 to 18 months after initial prescription of DAA therapy and no less than 12 weeks after the completion of treatment. Study participants will be invited to opt-in to medication adherence monitoring and quality of life assessments using validated self-reported instruments (EQ-5D-5L).

Discussion

PLATINUM C is a treatment registry and platform for nesting pragmatic trials. Data collected will inform the design, development and implementation of pragmatic trials. The digital infrastructure, study procedures and governing systems established by the registry will allow PLATINUM C to support a wider research platform in the management of hepatitis C in primary care.

Trial registration

The trial is registered with the Australia and New Zealand Clinical Trials Register (ACTRN12619000023156). Date of registration: 10/01/2019.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12879-020-05531-4.

The ORVAC trial: a phase IV, double-blind, randomised, placebo-controlled clinical trial of a third scheduled dose of Rotarix rotavirus vaccine in Australian Indigenous infants to improve protection against gastroenteritis: a statistical analysis plan

Objective

The purpose of this double-blind, randomised, placebo-controlled, adaptive design trial with frequent interim analyses is to determine if Australian Indigenous children, who receive an additional (third) dose of human rotavirus vaccine (Rotarix, GlaxoSmithKline) for children aged 6 to < 12 months, would improve protection against clinically significant all-cause gastroenteritis.

Participants

Up to 1000 Australian Aboriginal and Torres Strait Islander (hereafter Indigenous) infants aged 6 to < 12 months will be recruited from all regions of the Northern Territory.

Interventions

The intervention is the addition of a third scheduled dose of human monovalent rotavirus vaccine.

Co-primary and secondary outcome measures

ORVAC has two co-primary outcomes: (1) anti-rotavirus IgA seroconversion, defined as serum anti-rotavirus IgA ≥ 20 U/ml 28 to 55 days post Rotarix/placebo, and (2) time from randomisation to medical attendance for which the primary reason for presentation is acute gastroenteritis or acute diarrhoea illness before age 36 months. Secondary outcomes include (1) change in anti-rotavirus IgA log titre, (2) time from randomisation to hospitalisation with primary admission code presumed or confirmed acute diarrhoea illness before age 36 months, (3) time from randomisation to hospitalisation for which the admission is rotavirus confirmed diarrhoea illness before age 36 months and (4) time from randomisation to rotavirus infection (not necessarily requiring hospitalisation) meeting the jurisdictional definition before age 36 months.

Discussion

A detailed, prospective statistical analysis plan is presented for this Bayesian adaptive design. The plan was written by the trial statistician and details the study design, pre-specified adaptative elements, decision thresholds, statistical methods and the simulations used to evaluate the operating characteristics of the trial. As at August 2020, four interim analyses have been run, but no stopping rules have been triggered. Application of this SAP will minimise bias and supports transparent and reproducible research.

Trial registration

Clinicaltrials.gov NCT02941107. Registered on 21 October 2016

Original protocol for the study

10.1136/bmjopen-2019-032549

Effect of Selepressin vs Placebo on Ventilator- and Vasopressor-Free Days in Patients With Septic Shock: The SEPSIS-ACT Randomized Clinical Trial

IMPORTANCE

Norepinephrine, the first-line vasopressor for septic shock, is not always effective and has important catecholaminergic adverse effects. Selepressin, a selective vasopressin V1a receptor agonist, is a noncatecholaminergic vasopressor that may mitigate sepsis-induced vasodilatation, vascular leakage, and edema, with fewer adverse effects.

OBJECTIVE

To test whether selepressin improves outcome in septic shock.

DESIGN, SETTING, AND PARTICIPANTS

An adaptive phase 2b/3 randomized clinical trial comprising 2 parts that included adult patients (n = 868) with septic shock requiring more than 5 μg/min of norepinephrine. Part 1 used a Bayesian algorithm to adjust randomization probabilities to alternative selepressin dosing regimens and to trigger transition to part 2, which would compare the best-performing regimen with placebo. The trial was conducted between July 2015 and August 2017 in 63 hospitals in Belgium, Denmark, France, the Netherlands, and the United States, and follow-up was completed by May 2018.

INTERVENTIONS

Random assignment to 1 of 3 dosing regimens of selepressin (starting infusion rates of 1.7, 2.5, and 3.5 ng/kg/min; n = 585) or to placebo (n = 283), all administered as continuous infusions titrated according to hemodynamic parameters.

MAIN OUTCOMES AND MEASURES

Primary end point was ventilator- and vasopressor-free days within 30 days (deaths assigned zero days) of commencing study drug. Key secondary end points were 90-day mortality, kidney replacement therapy-free days, and ICU-free days.

RESULTS

Among 868 randomized patients, 828 received study drug (mean age, 66.3 years; 341 [41.2%] women) and comprised the primary analysis cohort, of whom 562 received 1 of 3 selepressin regimens, 266 received placebo, and 817 (98.7%) completed the trial. The trial was stopped for futility at the end of part 1. Median study drug duration was 37.8 hours (IQR, 17.8-72.4). There were no significant differences in the primary end point (ventilator- and vasopressor-free days: 15.0 vs 14.5 in the selepressin and placebo groups; difference, 0.6 [95% CI, -1.3 to 2.4]; P = .30) or key secondary end points (90-day mortality, 40.6% vs 39.4%; difference, 1.1% [95% CI, -6.5% to 8.8%]; P = .77; kidney replacement therapy-free days: 18.5 vs 18.2; difference, 0.3 [95% CI, -2.1 to 2.6]; P = .85; ICU-free days: 12.6 vs 12.2; difference, 0.5 [95% CI, -1.2 to 2.2]; P = .41). Adverse event rates included cardiac arrhythmias (27.9% vs 25.2% of patients), cardiac ischemia (6.6% vs 5.6%), mesenteric ischemia (3.2% vs 2.6%), and peripheral ischemia (2.3% vs 2.3%).

CONCLUSIONS AND RELEVANCE

Among patients with septic shock receiving norepinephrine, administration of selepressin, compared with placebo, did not result in improvement in vasopressor- and ventilator-free days within 30 days. Further research would be needed to evaluate the potential role of selepressin for other patient-centered outcomes in septic shock.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02508649.

Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct

BACKGROUND

The effect of endovascular thrombectomy that is performed more than 6 hours after the onset of ischemic stroke is uncertain. Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy.

METHODS

We enrolled patients with occlusion of the intracranial internal carotid artery or proximal middle cerebral artery who had last been known to be well 6 to 24 hours earlier and who had a mismatch between the severity of the clinical deficit and the infarct volume, with mismatch criteria defined according to age (<80 years or ≥80 years). Patients were randomly assigned to thrombectomy plus standard care (the thrombectomy group) or to standard care alone (the control group). The coprimary end points were the mean score for disability on the utility-weighted modified Rankin scale (which ranges from 0 [death] to 10 [no symptoms or disability]) and the rate of functional independence (a score of 0, 1, or 2 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating more severe disability) at 90 days.

RESULTS

A total of 206 patients were enrolled; 107 were assigned to the thrombectomy group and 99 to the control group. At 31 months, enrollment in the trial was stopped because of the results of a prespecified interim analysis. The mean score on the utility-weighted modified Rankin scale at 90 days was 5.5 in the thrombectomy group as compared with 3.4 in the control group (adjusted difference [Bayesian analysis], 2.0 points; 95% credible interval, 1.1 to 3.0; posterior probability of superiority, >0.999), and the rate of functional independence at 90 days was 49% in the thrombectomy group as compared with 13% in the control group (adjusted difference, 33 percentage points; 95% credible interval, 24 to 44; posterior probability of superiority, >0.999). The rate of symptomatic intracranial hemorrhage did not differ significantly between the two groups (6% in the thrombectomy group and 3% in the control group, P=0.50), nor did 90-day mortality (19% and 18%, respectively; P=1.00).

CONCLUSIONS

Among patients with acute stroke who had last been known to be well 6 to 24 hours earlier and who had a mismatch between clinical deficit and infarct, outcomes for disability at 90 days were better with thrombectomy plus standard care than with standard care alone. (Funded by Stryker Neurovascular; DAWN ClinicalTrials.gov number, NCT02142283 .).

Abstract 3594: Adaptively randomized seamless-phase multiarm platform trial: Glioblastoma Multiforme Adaptive Global Innovative Learning Environment (GBM AGILE)

Traditional phase 3 clinical trials compare an experimental arm with control. They inefficiently use patients, time, and finances. Dramatic and rapid changes in biology makes such trials untenable. We describe an alternative drug development strategy that we are using in a particular setting, the trial GBM AGILE (Glioblastoma Multiforme Adaptive Global Innovative Learning Environment).

The trial’s design employs many innovations. Some aspects are similar to those of I-SPY 2 (see 4 articles in July 7, 2016 NEJM) but GBM AGILE extends I-SPY 2 in many ways. (1) It is a Bayesian platform trial that simultaneously evaluates many treatment arms (including combinations) from many companies. (2) Arms are added to the trial at any time and leave when they have been evaluated, whether positively or negatively. (3) An arm’s sample size is adaptive and based on frequent analyses of the trial results. (4) Every arm has an initial stage in which it is randomized adaptively: arms performing better in disease subtypes are assigned with higher probability to such patients. (5) An arm that performs sufficiently well in a disease subset moves seamlessly into a small (50-patient) confirmatory, registration stage in the same subset, with equal randomization against control. (6) All experimental arms are compared against a common control arm that is assigned to 20% of patients in every subtype; a bridging model takes advantage of having many arms in the trial and many comparisons among arms, and enables indirect randomization comparisons of all arms with all controls. (7) Patient subtypes are defined by line of therapy, MGMT methylation status for newly diagnosed patients, and biomarkers associated with targeted therapies, although adaptive randomization enables us to draw conclusions about off-target effects.

The many possible subtypes means that there are many possible drug indications. So there are many possible “error types” and no single definition of statistical power. For example, the trial may conclude that a drug’s indication is “recurrent, biomarker-positive” disease when in truth it is “all recurrent” disease. We show how the design addresses this issue and we define “pure type I error.”

GBM AGILE’s primary endpoint is overall survival (OS). To make the design more efficient we incorporate evaluations of patients’ statuses over time using a longitudinal model based on periodic MRI assessments and performance status. The longitudinal model and its components are not end points but rather provide auxiliary information that enables multiply imputing OS for surviving patients.

We represent the trial’s coordinating committees that are made up of more than 150 enthusiastic and devoted disease experts and advocates from around the globe, including from Australia and China. The U.S. FDA has been enormously helpful in designing GBM AGILE, especially as regards its potential for drug and biomarker registration.

Our approach provides a model for other diseases, including those outside of cancer.

Citation Format: Donald A. Berry, Todd Graves, Jason Connor, Brian Alexander, Timothy Cloughesy, Anna Barker, Scott M. Berry, for the GBM AGILE Global Alliance. Adaptively randomized seamless-phase multiarm platform trial: Glioblastoma Multiforme Adaptive Global Innovative Learning Environment (GBM AGILE) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3594. doi:10.1158/1538-7445.AM2017-3594

A genomic case study of mixed fibrolamellar hepatocellular carcinoma

We report the first comprehensive genomic analysis of a case of mixed conventional and fibrolamellar HCC (mFL-HCC). This study confirms the expression of DNAJB1:PRKACA, a fusion previously associated with pure FL-HCC but not conventional HCC, in mFL-HCC. These results indicate the DNAJB1:PRKACA fusion has diagnostic utility for both pure and mixed FL-HCC.

Background

Mixed fibrolamellar hepatocellular carcinoma (mFL-HCC) is a rare liver tumor defined by the presence of both pure FL-HCC and conventional HCC components, represents up to 25% of cases of FL-HCC, and has been associated with worse prognosis. Recent genomic characterization of pure FL-HCC identified a highly recurrent transcript fusion (DNAJB1:PRKACA) not found in conventional HCC.

Patients and Methods

We performed exome and transcriptome sequencing of a case of mFL-HCC. A novel BAC-capture approach was developed to identify a 400 kb deletion as the underlying genomic mechanism for a DNAJB1:PRKACA fusion in this case. A sensitive Nanostring Elements assay was used to screen for this transcript fusion in a second case of mFL-HCC, 112 additional HCC samples and 44 adjacent non-tumor liver samples.

Results

We report the first comprehensive genomic analysis of a case of mFL-HCC. No common HCC-associated mutations were identified. The very low mutation rate of this case, large number of mostly single-copy, long-range copy number variants, and high expression of ERBB2 were more consistent with previous reports of pure FL-HCC than conventional HCC. In particular, the DNAJB1:PRKACA fusion transcript specifically associated with pure FL-HCC was detected at very high expression levels. Subsequent analysis revealed the presence of this fusion in all primary and metastatic samples, including those with mixed or conventional HCC pathology. A second case of mFL-HCC confirmed our finding that the fusion was detectable in conventional components. An expanded screen identified a third case of fusion-positive HCC, which upon review, also had both conventional and fibrolamellar features. This screen confirmed the absence of the fusion in all conventional HCC and adjacent non-tumor liver samples.

Conclusion

These results indicate that mFL-HCC is similar to pure FL-HCC at the genomic level and the DNAJB1:PRKACA fusion can be used as a diagnostic tool for both pure and mFL-HCC.

Adopting a Patient-Centered Approach to Primary Outcome Analysis of Acute Stroke Trials Using a Utility-Weighted Modified Rankin Scale

BACKGROUND AND PURPOSE

Although the modified Rankin Scale (mRS) is the most commonly used primary end point in acute stroke trials, its power is limited when analyzed in dichotomized fashion and its indication of effect size challenging to interpret when analyzed ordinally. Weighting the 7 Rankin levels by utilities may improve scale interpretability while preserving statistical power.

METHODS

A utility-weighted mRS (UW-mRS) was derived by averaging values from time-tradeoff (patient centered) and person-tradeoff (clinician centered) studies. The UW-mRS, standard ordinal mRS, and dichotomized mRS were applied to 11 trials or meta-analyses of acute stroke treatments, including lytic, endovascular reperfusion, blood pressure moderation, and hemicraniectomy interventions.

RESULTS

Utility values were 1.0 for mRS level 0; 0.91 for mRS level 1; 0.76 for mRS level 2; 0.65 for mRS level 3; 0.33 for mRS level 4; 0 for mRS level 5; and 0 for mRS level 6. For trials with unidirectional treatment effects, the UW-mRS paralleled the ordinal mRS and outperformed dichotomous mRS analyses. Both the UW-mRS and the ordinal mRS were statistically significant in 6 of 8 unidirectional effect trials, whereas dichotomous analyses were statistically significant in 2 to 4 of 8. In bidirectional effect trials, both the UW-mRS and ordinal tests captured the divergent treatment effects by showing neutral results, whereas some dichotomized analyses showed positive results. Mean utility differences in trials with statistically significant positive results ranged from 0.026 to 0.249.

CONCLUSIONS

A UW-mRS performs similar to the standard ordinal mRS in detecting treatment effects in actual stroke trials and ensures the quantitative outcome is a valid reflection of patient-centered benefits.

Core competencies in advanced training: what supervisors say about graduate training

In an attempt to identify needed mental health skills, many professional organizations have or are in the process of establishing core competency standards for their professions. The AAMFT identified 128 core competencies for the independent practice of MFT. The aim of this study was to learn the opinions of AAMFT Approved Supervisors as to how well prepared postgraduate trainees are when compared to the core competencies. One hundred thirty-five AAMFT Approved Supervisors provided their perspectives on (a) which competencies are most commonly learned in MFT graduate programs, (b) how well the graduates have mastered these competencies, and (c) the level to which the supervisors need the competencies to be mastered prior to entering advanced training. Results suggest that a gap exists between the level of mastery that the postgraduate trainees exhibit and the level desired by supervisors. Implications are suggested for closing this gap.

Effectiveness of a group opt-in session on uptake and graduation rates for pulmonary rehabilitation

Pulmonary rehabilitation (PR) is an effective intervention in the treatment of patients with chronic obstructive pulmonary disease (COPD). Unfortunately some patients offered this treatment either fail to take up the offer or fail to complete the course. Studies have indicated a number of factors influencing uptake and completion rates. We describe the introduction of an intervention, the group opt-in session (GOIS), prior to individualised baseline assessment and entry to the PR course, with the intention being to improve uptake and completion rates. A 1.5-hour-long GOIS was offered as the first face-to-face contact to all patients referred for PR. Drop-out rates at all stages of the pathway from referral to graduation were collected on 200 patients prior to the introduction of the GOIS (non-GOIS group) and compared to the first 400 patients following introduction (the GOIS group). Possible independent predictors of course uptake and completion were examined in the GOIS group. The proportion of referred patients taking up the offer of individualised baseline assessment or a GOIS was similar (75% vs. 72.2%, p value not significant [ns]). However, since in the GOIS group the opt-in session preceded the individualised baseline assessment and some patients opted-out, a smaller proportion of referred patients underwent this assessment than in the non-GOIS group (58.7% vs. 75%, p < 0.001). In addition, dropouts following individualised baseline assessments were also reduced (7% vs. 22%, p < 0.001). Both of these factors reduced ‘wasted’ assessments. Similar proportions of patients referred began the PR course in both groups (53% vs. 51.7%, ns), but a higher proportion of patients graduated in the GOIS group (87.9% vs. 76.4%, p < 0.05). Drop-out rates due to illness were similar in both groups (8.5% pre vs. 6.8% post, ns). However, drop-out rates not due to illness were much higher in the non-GOIS group (15.1% vs. 5.3%, p < 0.001). In the GOIS group, patients who did not attend the GOIS were, on average, younger (64.6 years vs. 69.7 years, p < 0.001) and had a higher mean percent predicted Forced Expiratory Volume (50.6% vs. 43.8%, p < 0.05) than those that did attend. A greater proportion of patients who opted in to the GOIS and attended the PR course lived less than 25 minutes from the PR centre than either those who did not attend the GOIS or who attended and then opted out (77.4% vs. 63%, p<0.005). The GOIS improved the graduation rates at The North Bristol Lung Centre PR Course and reduced wasted assessments. There was no effect on initial uptake. Analysis of the behaviour of patients invited to a GOIS suggested that age, lung function and travel distance were important factors influencing patient choice.

Accounting for seasonal patterns in syndromic surveillance data for outbreak detection

Background

Syndromic surveillance (SS) can potentially contribute to outbreak detection capability by providing timely, novel data sources. One SS challenge is that some syndrome counts vary with season in a manner that is not identical from year to year.

Our goal is to evaluate the impact of inconsistent seasonal effects on performance assessments (false and true positive rates) in the context of detecting anomalous counts in data that exhibit seasonal variation.

Methods

To evaluate the impact of inconsistent seasonal effects, we injected synthetic outbreaks into real data and into data simulated from each of two models fit to the same real data. Using real respiratory syndrome counts collected in an emergency department from 2/1/94–5/31/03, we varied the length of training data from one to eight years, applied a sequential test to the forecast errors arising from each of eight forecasting methods, and evaluated their detection probabilities (DP) on the basis of 1000 injected synthetic outbreaks. We did the same for each of two corresponding simulated data sets. The less realistic, nonhierarchical model's simulated data set assumed that "one season fits all," meaning that each year's seasonal peak has the same onset, duration, and magnitude. The more realistic simulated data set used a hierarchical model to capture violation of the "one season fits all" assumption.

Results

This experiment demonstrated optimistic bias in DP estimates for some of the methods when data simulated from the nonhierarchical model was used for DP estimation, thus suggesting that at least for some real data sets and methods, it is not adequate to assume that "one season fits all."

Conclusion

For the data we analyze, the "one season fits all " assumption is violated, and DP performance claims based on simulated data that assume "one season fits all," for the forecast methods considered, except for moving average methods, tend to be optimistic. Moving average methods based on relatively short amounts of training data are competitive on all three data sets, but are particularly competitive on the real data and on data from the hierarchical model, which are the two data sets that violate the "one season fits all" assumption.

Surveying Saccharomyces genomes to identify functional elements by comparative DNA sequence analysis

Comparative sequence analysis has facilitated the discovery of protein coding genes and important functional sequences within proteins, but has been less useful for identifying functional sequence elements in nonprotein-coding DNA because the relatively rapid rate of change of nonprotein-coding sequences and the relative simplicity of non-coding regulatory sequence elements necessitates the comparison of sequences of relatively closely related species. We tested the use of comparative DNA sequence analysis to aid identification of promoter regulatory elements, nonprotein-coding RNA genes, and small protein-coding genes by surveying random DNA sequences of several Saccharomyces yeast species, with the goal of learning which species are best suited for comparisons with S. cerevisiae. We also determined the DNA sequence of a few specific promoters and RNA genes of several Saccharomyces species to determine the degree of conservation of known functional elements within the genome. Our results lead us to conclude that comparative DNA sequence analysis will enable identification of functionally conserved elements within the yeast genome, and suggest a path for obtaining this information.

Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana

The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

Office-based surgery and cost avoidance in an obstetrics and gynecology residency program

AUDIENCE

This article is designed both for graduate medical educators and financial officers of teaching hospitals.

GOAL

To present the financial and clinical implications of a resident-run, attending-supervised office-based surgery center.

OBJECTIVES

1. Describe the recent changes in volume of patients available for resident education in obstetrics and gynecology. 2. Describe the accounting method of calculating the cost of office versus hospital outpatient procedures. 3. Describe the financial and educational benefits of an office-based surgery program run by residents with the supervision of attending physicians.

Effect of aspirin and ifetroban on skeletal muscle blood flow in patients with congestive heart failure treated with Enalapril. Ifetroban Study Group

OBJECTIVES

The purpose of this study was to determine the acute and chronic effects of cyclooxygenase inhibition with aspirin and thromboxane A2 receptor blockade with ifetroban on the chronic vasodilating effects of enalapril in the skeletal muscle circulation of patients with heart failure.

BACKGROUND

Angiotensin-converting enzyme inhibition and antiplatelet therapy with aspirin independently reduce the risk for subsequent nonfatal coronary events in survivors of myocardial infarction. The safety of the combined administration of angiotensin-converting enzyme inhibitors and aspirin has been questioned due to their divergent effects on the vascular synthesis of vasodilating prostaglandins.

METHODS

Forearm blood flow (ml/min/100 ml) at rest and during rhythmic handgrip exercise and after transient arterial occlusion was determined by strain gauge plethysmography before and 4 h and six weeks after combined administration of enalapril with either aspirin, ifetroban or placebo in a multicenter, double-blind, randomized trial of 62 patients with mild to moderate heart failure.

RESULTS

Before randomization, forearm hemodynamics were similar in the three treatment groups except for increased resting forearm blood flow and decreased resting forearm vascular resistance in the aspirin group when compared with the placebo group. After combined administration of enalapril and study drug for 4 h and six weeks, changes from prerandomization values of mean arterial pressure, forearm blood flow and forearm vascular resistance at rest, during handgrip exercise and after transient arterial occlusion did not differ among the three treatment groups.

CONCLUSIONS

These findings demonstrate that the vasodilating effects of enalapril in the skeletal muscle circulation of patients with heart failure are not critically dependent on prostaglandin pathways.

First reported case of hantavirus pulmonary syndrome in Oklahoma

Hantavirus Pulmonary Syndrome (HPS) is a condition of rapidly progressive pulmonary failure with a case-fatality rate of almost 50 percent. Rodents serve as the reservoir for hantaviruses and human infection occurs primarily via aerosolized virus in rodent excreta. The rodent reservoir for the disease is widespread across Oklahoma and the first case of HPS has recently been confirmed in an Oklahoma resident. Physicians should suspect HPS in a previously healthy person who develops a febrile illness and respiratory insufficiency and has potentially been exposed to the virus. Common laboratory findings include a left-shifted neutrophilic leukocytosis, elevated hematocrit and thrombocytopenia. Therapy is supportive. If HPS is suspected, the patient should be immediately transferred to a facility that can provide aggressive supportive care.

Precise mapping and characterization of the RNA primers of DNA replication for a yeast hypersuppressive petite by in vitro capping with guanylyltransferase

The active origins of DNA replication for yeast (Saccharomyces cerevisiae) mitochondrial DNA share 280 conserved base pairs and have a promoter. Since intact replication intermediates retain their initiating ribonucleotide triphosphate, we used guanylyltransferase to in vitro cap the replication intermediates present in restriction enzyme-cut DNA from an ori-5 hypersuppressive petite. Restriction mapping and RNA sequencing of these labeled intermediates showed that each DNA strand is primed at a single discrete nucleotide, that one primer starts at the promoter and that the other primer starts 34 nt away, outside the conserved region. Deoxyribonuclease digestion of the capped fragments left resistant RNA primers, which enabled identification of zones of transition from RNA to DNA synthesis. Some of the results contradict the prevailing model for priming at the yeast mitochondrial origins.

Adverse events after discontinuing medications in elderly outpatients

BACKGROUND

Discontinuation of drug therapy is an important intervention in elderly outpatients receiving multiple medications, but it may be associated with adverse drug withdrawal events (ADWEs).

OBJECTIVE

To determine the frequency, types, timing, severity, and factors associated with ADWEs after discontinuing medications in elderly outpatients.

PATIENTS

One hundred twenty-four ambulatory elderly participants in 1-year health service intervention trial at the Durham Veterans Affairs General Medicine Clinic in Durham, NC, who stopped taking medications.

METHODS

A geriatrician retrospectively reviewed computerized medication records and clinical charts to determine medications no longer being taken and adverse events in the subsequent 4-month period. Possible ADWEs, determined by using the Naranjo causality algorithm, were categorized by therapeutic class, organ system, and severity.

RESULTS

Of 238 drugs stopped, 62 (26%) resulted in 72 ADWEs among 38 patients. Cardiovascular (42%) and central nervous system (18%) drug classes were most frequently associated with ADWEs. The ADWEs most commonly involved the circulatory (51%) and central nervous (13%) systems, and 88% were attributed to exacerbations of underlying disease. Twenty-six ADWEs (36%) resulted in hospitalization or an emergency department or urgent care clinic visit. Only the number of medications stopped was associated with ADWE occurrence (adjusted odds ratio, 1.89; 95% confidence interval, 1.33-2.67).

CONCLUSIONS

Most medications can be stopped in elderly outpatients without an ADWE occurrence. However, when ADWEs occur they resulted in substantial health care utilization. Practitioners should strive to discontinue drug therapy in the elderly but be vigilant for disease recurrence.

Case report: locally acquired trichinosis in an immigrant from Southeast Asia

The authors report a case of trichinosis acquired in Oklahoma City by an immigrant from Southeast Asia. The 49-year-old female reported having abdominal discomfort, nausea, and vomiting, and had purchased and eaten lightly cooked pork. She also complained of fatigue, anorexia, and muscle aches for several months. An immigrant from Laos, she stated that she regularly eats pork and prefers it rare or mildly cooked. The authors caution local physicians to be aware of the increased risk of trichinosis among Southeast Asian immigrants in the area, particularly those from Laos and Cambodia. Continued emphasis on the need to thoroughly cook all pork products is necessary if the incidence of trichinosis in the U.S. is to be controlled.

HIV seroprevalence in Oklahoma childbearing women

From October 1989 through September 1990, we conducted an unlinked seroprevalence survey in Oklahoma to determine the prevalence of human immunodeficiency virus, type 1 (HIV) in women at the time of childbirth. Blood specimens obtained from 41,809 newborns in conjunction with the state's newborn metabolic screening program were tested for HIV after personal identifiers were removed. The overall HIV seroprevalence rate was 0.02% (10/41,809). Rates were highest for mothers aged 30 to 39 years (0.06%, 3/5,158). No difference was found between the HIV seroprevalence rates for women residing in standard metropolitan areas (MSAs) of the state (0.03%, 6/21,105) and women residing in non-metropolitan areas (0.03%, 3/11,904). When compared to other states where surveys have been done, Oklahoma's rate of HIV infection in childbearing women was low.

Advances in antineoplastic therapy

Despite advances in early diagnosis and treatment of cancer, more than a million new cases of cancer will have been diagnosed in 1990, with an estimated 10% mortality within a year of diagnosis. Thus, the search continues for new or improved antineoplastic agents with a wide spectrum of activity and decreased toxicity. The major advances in single-agent antineoplastic drug therapy include the introduction of cisplatin almost 20 years ago and of etoposide (VP-16) in the mid-1980s. However, within the past two years, analogues of existing antineoplastic agents have been purified and marketed. These drugs offer an enhanced therapeutic index when used alone or in combination with other therapies as well as decreased toxicity and, thus, may enhance patient tolerance.

Ondansetron: a new entity in emesis control

Nausea and vomiting are serious problems for patients receiving cancer chemotherapy. Dopamine receptor and cholinergic receptor antagonism have been the target mechanism for agents used to combat drug-induced nausea and vomiting; more recently, blockade of serotonin receptors has been used for this indication. Current therapies are limited by extrapyramidal adverse effects, as well as drowsiness, sedation, respiratory depression, and cardiac effects. Ondansetron is an investigational serotonin antagonist that has documented effectiveness for cancer chemotherapy-induced emesis. Ondansetron appears to be well tolerated, with the possible exception of headaches and transient increases in liver enzymes. No extrapyramidal toxicities have been reported with this agent. While ondansetron looks promising, further studies are needed to fully define its role as an antiemetic.

Early postoperative intraperitoneal chemotherapy as an adjuvant therapy to surgery for peritoneal carcinomatosis from gastrointestinal cancer: pharmacological studies

Gastrointestinal malignancy may spread to peritoneal surfaces in the absence of lymphatic or hematogenous metastases. To treat peritoneal carcinomatosis, a uniformly lethal disease process, extensive cytoreductive surgery and i.p. chemotherapy were combined. Early postoperative i.p. chemotherapy was instilled in the first few days after the surgical procedure in an attempt to treat anatomic sites that would be sealed off by postoperative adhesions. Mitomycin C was given on the first postoperative day at two doses, 10 and 12 mg/m2. 5-Fluorouracil was given on postoperative days 2-5 at 15 and 20 mg/kg, respectively. Median area under the curve ratio i.p./i.v. was 117 for 5-fluorouracil and 21.6 for mitomycin C. Elevated intraportal levels of drug were observed for i.p. 5-fluorouracil but not for mitomycin C. The marked pharmacokinetic advantage of postoperative i.p. suggests that this treatment strategy should be considered in a clinical trial in patients at risk for progression of peritoneal carcinomatosis.

Rationale for integrating early postoperative intraperitoneal chemotherapy into the surgical treatment of gastrointestinal cancer

A new concept in the natural history of gastrointestinal (GI) cancer suggests that recurrence of this malignancy can be separated into two types. Hematogenous and lymphatic metastases occur before surgical removal of the primary cancer. The spread of cancer to the resection site and to peritoneal surfaces occurs at the time of surgical removal of the primary tumor. Surgical trauma leads to a dispersal of malignant tumor emboli, which then implant within the raw tissue surfaces of the resection site and abraded peritoneal surfaces. Instillation of chemotherapy directly into the peritoneal cavity, as part of GI surgery, provides cytotoxic levels of drug that may change the natural history of GI cancer. The most common sites of disease recurrence have been, in the past, at the resection site and on peritoneal surfaces. With the optimal use of intraperitoneal chemotherapy, these sites of surgical treatment failure should no longer occur. Early phase I and II and pharmacologic studies suggest that an effective dose and schedule have been achieved, that toxicity is at reasonable levels, and that responses with small volumes of intra-abdominal cancer are exceptionally high. Chemotherapy that has an impact on the surgical event by decreasing cancer spread to the resection site and to peritoneal surfaces may significantly improve survival and quality of life in patients with GI cancer.

Acral erythema secondary to high-dose cytosine arabinoside with pain worsened by cyclosporine infusions

Acral erythema after high-dose cytosine arabinoside (Ara-C) has been described as a painful, sharply demarcated, and intense erythema of the palms and soles. This phenomenon occurred and is described in three out of three allogeneic bone marrow transplant (BMT) recipients who received high-dose Ara-C and total-body irradiation for conditioning therapy via the same protocol. These patients also received cyclosporine and methotrexate as prophylaxis for acute graft-versus-host disease. Two of the three patients experienced an increase in the pain associated with acral erythema during cyclosporine infusions and required large doses of narcotic analgesics. Since alcohol intensifies the pain of stomatitis and cyclosporine is manufactured in an alcohol base, the high alcohol content is suspect as the causative factor for this adverse reaction/drug interaction.

Drug-induced toxicities associated with high-dose cytosine arabinoside infusions

The frequency and significance of central nervous system (CNS), ocular, and dermatologic toxicities associated with high-dose cytosine arabinoside (HDARA-C) infusions was evaluated. Patients were selected from one of three Southeastern Cancer Study Group protocols using HDARA-C 2-3 g/m2 body surface area (BSA) and their medical records were reviewed to identify and document the frequency of the toxicities. Those exhibiting CNS toxicity were compared across age, sex, race, previous standard-dose ARA-C or HDARA-C therapy, and infusion rate for toxicity occurrence. Statistical analysis was performed using Fisher's exact test with p less than 0.05. Of the 53 patients evaluated, 37.7% exhibited CNS, 37.7% ocular, and 45.3% dermatologic toxicities. Of the risk factors evaluated, only increasing age and previous ARA-C therapy approached statistical significance. The CNS toxicities associated with HDARA-C are clinically significant since permanent damage may result. Ocular and dermatologic toxicities usually resolve without medical intervention when HDARA-C therapy is discontinued. Further study is necessary to determine appropriate prophylaxis for these toxicities.

On the interaction of cobra venom protein cardiotoxins with erythrocytes

The principally active hemolytic toxin (cardiotoxin) previously purified from the venom of the Thailand cobra, Naja naja siamensis, was shown to produce spontaneous twitching, contractures and membrane depolarization in sartorius muscles from the frog, Rana pipiens. Spontaneous twitching, observed at concentrations greater than 0.1 uM was completely abolished by addition of tetrodotoxin and not affected by d-tubocurarine. Dose and time dependent membrane depolarization of muscle fibers was observed to occur within 10-30 min at 0.2 to 1.0 uM concentrations of the toxin. These observations, taken together with an amino acid analysis characteristic of previously described cobra venom cardiotoxins, characterized this hemolytic toxin as a cardiotoxin. In the absence of EDTA the initial velocities of erythrocyte hemolysis for this toxin showed a sigmoidal concentration dependence which became hyperbolic in the presence of EDTA. The largest increases in hemolysis rates on addition of 1 mM EDTA were observed at low toxin concentrations. In the presence of EDTA extracellular and membrane associated divalent cations are complexed, thus alleviating their competition with toxin for binding to the membrane, a key and apparently rate-determining initial step which leads to hemolysis. In the presence of EDTA hemolysis rates increased linearly at low toxin concentration and reached an extrapolated maximum value at toxin concentrations at which, given its molecular dimensions, there are just sufficient toxin molecules to cover the entire membrane surface area provided by the erythrocytes.

Treatment of L-asparaginase allergic reaction

The treatment of an allergic reaction to L-asparaginase is discussed in the presentation of a case of a 26-year-old man with chronic myelogenous leukemia who was undergoing methotrexate-L-asparaginase rescue therapy. The possible mechanism of action of L-asparaginase is reviewed, and precautions for use of L-asparaginase in combination therapy with methotrexate are presented.

Late sequelae of allergic bronchopulmonary aspergillosis

Seven patients with late sequelae of allergic bronchopulmonary aspergillosis (ABPA) are described. All seven had significant chronic symptoms from asthma. At the time of diagnosis of ABPA all patients had marked irreversible pulmonary function abnormalities; symptoms of chronic bronchitis were present in all. Pulmonary fibrosis was present in six of seven patients. Three patients have died from irreversible lung disease with terminal cardiac failure. Despite the difficulty in establishing an early diagnosis of ABPA, its importance must be emphasized in order to attempt to prevent progression of the disease to severe irreversible and potentially fatal end-stage lung disease.