Memory encoding and retrieval in the aging brain

Decline in episodic memory, the encoding and retrieval of autobiographical events, is a hallmark of normal cognitive aging. Although the primary causes of this decline remain elusive, event-related brain potential (ERP) studies have contributed to an understanding of age-related episodic memory failure. These data reveal that, although the retrieval-based episodic memory (EM) effect does not differ dramatically between young and older adults, the acquisition-related data suggest a decline in episodic encoding (i.e., semantic elaboration) with increasing age. We conclude that, at the current state of knowledge, encoding deficiencies are more important than retrieval deficits in understanding the causes of episodic memory decline in the older adult.

Selecting promising ALS therapies in clinical trials

Riluzole is the only approved medication that extends survival for patients with amyotrophic lateral sclerosis (ALS). While other potential neuroprotective agents have been evaluated in randomized clinical trials, none has shown unequivocal success and none has been approved by regulatory agencies. Few symptomatic therapies have been tested in ALS. Effectiveness for drugs with modest benefit can be established only through large phase III randomized clinical trials. With numerous potential agents but limited resources, priority should be given to agents that show promise in phase II trials before proceeding to evaluation in phase III trials. In this article, we review drug development in early phase ALS trials and introduce novel designs. First, to maximize the therapeutic potential of the test medication, we need to identify the highest dose that produces a tolerable level of side effects. Second, candidate treatments should be ranked by conducting randomized selection trials between competing new treatments. The selection paradigm adopts a statistical viewpoint different from the hypothesis testing framework in conventional trials. We exemplify this approach by describing a group-sequential selection design developed for a phase II, randomized, multicenter trial of two combination treatments in patients with ALS, and illustrate the sample size reduction from a conventional trial.

Palliation and supportive care in radiation medicine

The treatment of bone metastases represents a paradigm for evaluating palliative care in terms of symptom relief, toxicities of therapy, and the financial burden to the patient, caregivers, and society. Despite enormous expenditures to treat metastases, patients continue to sustain symptoms of the disease, and uninterrupted aggressive therapies are pursued until death that incur toxicity in approximately 25% of patients. This approach is inconsistent with the goals of palliative care, which should efficiently provide comfort using antineoplastic therapies or supportive care approaches to the patient with the fewest treatment-related side effects, recognizing that the patient will die of the disease.The development of therapies such as bisphosphonates is important in advancing options for palliative care; however, clinical trials demonstrating the efficacy of bisphosphonates have not addressed important issues for clinical practice. The primary study endpoints should primarily address pertinent patient outcomes such as pain relief rather than asymptomatic radiographic findings. These studies should define clear indications of when to start and stop the therapy, the appropriate patient populations to receive the therapy, and the cost effectiveness of the treatment relative to other available therapies such as radiation. Cost-utility analyses, which account for a broader domain of cost effectiveness, need to be performed as part of clinical trials, especially for palliative care endpoints. Clinical trials that include these criteria are critical to future practice guideline development. As health care resources continue to become more limited, the criteria for care must be better defined to avoid administration of therapy with limited benefit. Leadership must come from the specialty as clinical trials and clinical practice increasingly interface with health care policy. Goals of therapy must remain clear for the benefit of the individual and all patients.

Clinical trials for drug approval: a pilot study of the view of doctors at Tokushima University Hospital

The development of new and useful pharmaceutical drugs is essential in order to improve the quality of drug therapeutics. Clinical trials play a central role in drug development. Over time, the clinical trial infrastructure has improved and is now integrating the contribution of clinical research coordinators (CRC). Nevertheless, the attitude of doctors towards clinical trials still favors conventional/historical methodologies. In the present study, we explored the view of doctors towards clinical trials for drug development, in order to improve communication among participants, sponsors, and investigators.A questionnaire was designed for this pilot study. The questionnaire included general attitudes, difficult points, the benefit of doctors in participating as investigators, special attention requirements, and the expected role of CRC in clinical trials for drug approval. In addition, the appropriate use of the outpatient clinic was examined. The questionnaire was provided to doctors in each department of Tokushima University Hospital in 2000 and 2004. Because of the small number of subjects included in this pilot study, no statistical analysis is presented. A total of 89 (81%) and 62 (56%) doctors among 110 responded to the survey in 2000 and 2004, respectively. Inquiries about the familiarity of the physicians with clinical trials for drug approval revealed that 84% in 2000 and 66% in 2004 were aware of such trials. The attitude towards participating as investigators in the clinical trials was favorable, with a response of 66% in 2000 and 58% in 2004. Patients' refusal and the informed consent process were considered difficult areas by many doctors. Expected roles of CRC included activities based on the nurse's specialty. Although many doctors agreed to take care of the study participants separately from the clinical practice, they lacked the time to do so. In spite of the doctors' workload reduction by introduction of the CRC concept, their views regarding clinical trials for drug approval remain conventional. Further refinement in the support process by CRC should be considered in our hospital, and the views of the doctors should be investigated in a larger study, in order to promote clinical trials for drug approval in Japan.

Predictors of delay in the diagnosis and clinical trial entry of amyotrophic lateral sclerosis patients: A population-based study

BACKGROUND

The El Escorial and the revised Airlie House diagnostic criteria for amyotrophic lateral sclerosis (ALS) were introduced to select patients for clinical trials. Heterogeneity of clinical presentation at onset and delay in diagnosis may decrease the likelihood for trial entry.

OBJECTIVE

Identify risk factors for delay in the diagnosis and trial exclusion.

METHODS

ALS incident cases were identified with El Escorial (EEC) and Airlie House criteria (AHC) through a population-based registry established in Puglia, Southern Italy, in the years 1998-99.

RESULTS

130 ALS incident cases were diagnosed with a median interval between onset of symptoms and diagnosis of 9.3 months and not different across both EEC and AHC categories. Twenty percent of cases were not eligible for clinical trials according to the AHC. About 5% of subjects in this series died with only lower motor neuron signs. Predictors for delay in the diagnosis were age between 65 and 75 years and spinal onset while fasciculations and cramps as first symptoms were predictors of exclusion from trials.

CONCLUSIONS

In this population-based series, diagnostic delay was longer in subjects with spinal onset and age between 65 and 75 and fasciculation as first symptoms. About 80% of incident cases were trial eligible with AHC criteria. However, a significant number of subjects with ALS, characterized by a limited spread of signs, were not trial eligible while alive.

Association of industry sponsorship to published outcomes in gastrointestinal clinical research

BACKGROUND & AIMS

Recent years have seen an increase in industry sponsorship of clinical trials throughout medicine. We conducted a study to evaluate the association of industry sponsorship to published outcomes in gastrointestinal (GI) clinical research. Our aims were (1) to evaluate the trends in the source of funding for GI clinical research during the period from 1992 to 2002-2003, (2) to determine whether the source of study funding predicted the likelihood that a study would publish results that favor the drug or device being tested, and (3) to determine whether differences exist in the methodologic quality of the investigational study methods used in studies funded by private industry versus other sources.

METHODS

We selected all clinical studies evaluating a drug or device from 4 prominent GI journals (Gastroenterology, The American Journal of Gastroenterology, Hepatology, and Gastrointestinal Endoscopy). All studies were abstracted by using a standardized data abstraction form. We evaluated the trends in funding source for studies published during the years 1992, 2002, and 2003. All selected studies were scored for methodologic quality by using a previously validated scoring system. The percentage of studies that reported outcomes that favored the device or drug being tested against the standard therapy or placebo was determined for each funding source. A funnel plot was constructed to assess for the presence of negative publication bias.

RESULTS

A total of 6326 studies were reviewed. For the 1992 trend data, 1860 studies were reviewed, and 135 were selected for inclusion in the study. Ninety-five studies were studies involving the investigation of drugs, and 40 studies involved the testing of a device. For the 2002-2003 data 4466 studies were reviewed, and 315 were selected for inclusion in the study. Two hundred twenty-two studies were clinical trials involving the investigation of drugs, and 93 were clinical trials involving devices. In comparing 1992 to 2002, the percentage of studies funded by industry sources more than doubled from 10% to greater than 28% of the total studies assessed. There was an associated decline in the proportion of studies with funding from non-industry sources during this period (62% to less than 48%). The percentage of studies that did not disclose a funding source fell modestly from 28% to 24%. We found that 86% of studies funded by private industry reported a result favorable to the study drug or device, and 83% of studies funded by academic sources reported a result favorable to the study drug or device (P=.572). On average, studies funded by private industry had a higher methodology score than studies funded by traditional academic sources (75 of 100 vs 65 of 100; P=.005). Analysis of the funnel plot did not reveal evidence of bias against the publication of small studies with insignificant results.

CONCLUSIONS

The proportion of research funded by industry has more than doubled during the last decade and currently comprises almost half of the funding for GI clinical research. Industry-sponsored studies are, on average, of superior methodologic quality to studies funded by other sources. Industry-sponsored studies in leading GI journals were no more likely than other studies to publish results that favored the study sponsor, although an extremely high percentage of all studies in these journals reported positive results. There has been only a modest decline in studies not acknowledging a funding source.

Highly purified omega-3 polyunsaturated fatty acids in clinical development

Highly purified omega-3 polyunsaturated fatty acids (PUFAs) (Omacor) is the focus of an extensive and ambitious clinical development program that seeks to build on the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-Prevenzione study. Studies currently in progress include very large clinical outcome trials designed to evaluate the impact of omega-3 PUFAs on death and major morbid events in defined patient populations such as individuals with heart failure or diabetes, specialist investigations in very high-risk populations such as patients requiring hemodialysis, and a range of specialized studies concerned with mechanisms of action and effects on biochemical and laboratory indices. The emergence of results from these studies can be expected to define a spectrum of indications for omega-3 PUFAs in the management of cardiovascular and renal disease.

Clinical trials of natural products as chemopreventive agents for prostate cancer

Epidemiological research on prostate cancer risk in men throughout the world has identified significant correlations between dietary habits and prostate cancer occurrence. These studies served as a catalyst for exploration into the potential of dietary substances to act as chemopreventive agents against this disease, and include green tea catechins, lycopene, soy isoflavones, pomegranate phenolics, selenium, vitamins E and D, curcumin and resveratrol. Before these agents (in the dietary or purified forms) can be recommended as useful chemopreventive strategies for patients, their activity must be confirmed in rigorously designed clinical trials. This review discusses the preclinical and clinical data available for these dietary agents and describes relevant clinical trials currently being conducted.

The second National Institutes of Health International Congress on advances in uterine leiomyoma research: conference summary and future recommendations

OBJECTIVE

To summarize the proceedings of the Advances in Uterine Leiomyoma Research: 2nd NIH International Congress, which was convened on February 24-25, 2005 by the Department of Health and Human Services (DHHS), National Institutes of Health (NIH) in Bethesda, Maryland.

DESIGN

Scientific information was presented at a 2-day conference, which was a collaborative effort of agencies across the DHHS and members of the academic, clinical, and medical communities involved in uterine leiomyoma research.

CONCLUSION(S)

The conference brought together scientists in biomedicine, epidemiology, basic research, therapeutics, and translational medicine and fostered an exchange of scientific information among members of the uterine leiomyoma research and health care communities. This document summarizes this exchange and outlines research needs and recommendations for future research directions.

[On the relation between binaural difference potentials and directional hearing]

BACKGROUND

Central auditory processing disorders (CAPD) are associated with reduced discriminatory abilities of the auditory system. One of these abilities is directional hearing, which is based on the evaluation of interaural signal differences. Since these differences affect also the binaural difference potentials (BDP), these derived evoked potentials could be suitable for the objective detection of disabilities in acoustic localization.

METHOD

Auditory brainstem responses (ABR) evoked by monaural and binaural stimulation were recorded in 32 adult normal-hearing volunteers at stimulus levels between 10 and 80 dB nHL and the BDP were derived. Additionally, a test of directional hearing was performed and evaluated.

RESULTS

BDP are detectable at all stimulus levels without difficulties, with acceptable examination times and with satisfactory reliability in a routine clinical environment. The electrodes can be positioned at the mastoid (A1 and A2) and vertex (Cz) as for conventional ABR recording. Normal ranges are given for latency and amplitude as well as for their lateral differences.

CONCLUSION

The spectrum in directional hearing ability as covered by normal-hearing subjects is not mirrored in the parameters of their BDP. Nevertheless, it cannot be ruled out that a real impairment of directional hearing goes along with significantly altered BDP.

Use of the foreign studies: transposition of the results, prediction of the therapeutic effects in the french population, modelling of the public health interest

More and more frequently, the health authorities and the French assessment agencies are led to issue Marketing Authorizations (MAs), give opinions on the eligibility for reimbursement of drugs or to draft recommendations for clinical practice based on the results of foreign studies. The results of these studies are more or less difficult to transpose to French practice. These difficulties generate varying degrees of uncertainty concerning the effect to be expected of a drug. A more or less extensive loss of effect is sometimes even predictable. Some of the difficulties in transposition are discussed in this article and proposals for action are made in order to allow one, in the long term, to predict in the most precise manner possible the effects to be expected from a drug in the French population and be able to verify this prediction at an interval from its eligibility for reimbursement.

Clinical trials in pediatric traumatic brain injury: unique challenges and potential responses

In order to optimize pediatric traumatic brain injury translational and clinical research, scientific and ethical challenges need to be recognized and addressed. Having recently conducted a multisite phase II safety/feasibility trial of magnesium sulfate as a neuroprotective agent, we supplement our own experience by a mini review of similar studies, identifying challenges and possible responses from the perspective of families, investigators, funding agencies and society.