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Biomedical subjects

C Anello

Publications and source records attributed to C Anello.

16 recordsLinked to original sources
PubMed1997

High resolution EEG: a new model-dependent spatial deblurring method using a realistically-shaped MR-constructed subject's head model.

This paper presents a new model-dependent method for the spatial deblurring of scalp-recorded EEG potentials based on boundary-element and cortical imaging techniques. This model-dependent spatial deblurring (MDSD) method used MR images for the reconstruction of the subject's head model, and a layer of 364 radially-oriented equivalent current dipoles as a source model. The validation of the MDSD method was performed on simulated potential distributions generated from equivalent dipoles oriented radially, obliquely, and tangentially to the head surface. Furthermore, this method was used to localize neocortical sources of human movement-related and somatosensory-evoked potentials. It was shown that the new MDSD method improved markedly the spatial resolution of the simulated surface potentials and scalp-recorded event-related potentials. The spatial information content of the scalp-recorded EEG potentials increased progressively by increasing the spatial sampling from 28 to 128 channels. These results indicate that the new method could be satisfactorily used for high resolution EEG studies.

Brain↗
PubMed1997

Quality-of-life changes in patients with thyroid cancer after withdrawal of thyroid hormone therapy.

Quality of life (QOL) is an important consideration as patients survive longer with cancer and is an area of increasing interest in patients with thyroid cancer who undergo long-term cancer surveillance. However, there are few disease-specific QOL tools available to evaluate QOL in patients with thyroid cancer. The purposes of this longitudinal, repeated-measures study were to: (1) test a new instrument, the QOL-Thyroid Scale, during thyroid hormone withdrawal; and (2) to evaluate the impact of thyroid hormone withdrawal on patients' perceived changes in quality of life. The sample included 34 subjects (mean age 40 years) undergoing thyroid hormone withdrawal in preparation for scanning procedures. Subjects completed three instruments (demographic data tool, the QOL-Thyroid, and the FACT-G) at four specific time points in relationship to scanning. The results demonstrated that the QOL-Thyroid tool is a reliable and valid measure of QOL. Cronbach's alpha coefficient of r = .78 between QOL-Thyroid and FACT-G indicated good concurrent validity. Second, the impact of thyroid hormone withdrawal on QOL showed significant changes in physical, psychological, and social well-being across the four testing points. The greatest changes occurred between peak hormone withdrawal and thyroxine (T4) therapy. While it is generally known that patients suffer troublesome physical symptoms relating to thyroid hormone withdrawal, the negative psychological, family, and work sequelae are less apparent. In conclusion, the QOL-Thyroid is a reliable and valid measure for use in evaluating patients undergoing scanning procedures and may be used to identify and target teaching and support for high-risk areas in patients lives that are negatively affected by hormone withdrawal.

Adult↗
PubMed1995

Exploratory or analytic meta-analysis: should we distinguish between them?

Meta-analysis has been defined as a study and "statistical analysis which combines or integrates the results of several independent studies." Included in this definition are other terms, such as systematic overviews, pooling data, pooling study results, and quantitative literature reviews. Like any study, the questions being asked will influence the design and the method of analysis of the meta-analysis. Since a meta-analysis is a study based on a literature review, it is inherently observational rather than experimental in nature. This idea is supported by the fact that the meta-analyst has limited control over the availability of studies or the information collected and reported in the individual studies. Meta-analysis has been applied to clinical trials and epidemiology. At first glance the potential for bias appears greater in epidemiology than in clinical trials. But this may depend on the question being asked. If randomized clinical trials are limited to improving an estimate of effect or testing a hypothesis in a relatively homogeneous set of effect sizes, the clinical trial will tend to be less prone to bias than a comparable set of epidemiologic studies. In this context, the issue of combinability may dominate the meta-analysis. We refer to this type of meta-analysis as an "analytic" meta-analysis. On the other hand when the goal is to resolve controversy, or pose and answer new questions the main concern of the meta-analysis is to explain the variation in the effect sizes. We refer to this application of a meta-analysis as an "exploratory" meta-analysis. In this second type of meta-analysis the characteristics of the different studies become the focus of the analysis. This leads to the idea that protocols for a meta-analysis should reflect its goals and how the results are to be used. Finally, we will consider whether there is a role of meta-analysis in the field of drug development.

Bias↗
PubMed1986

Toxic shock syndrome and the vaginal contraceptive sponge.

Thirteen confirmed cases of toxic shock syndrome temporally related to use of the vaginal contraceptive sponge have been reported. The observed risk of toxic shock syndrome in sponge users may be elevated above estimated background rates, but this risk remains very low. Traumatic manipulation of the sponge, use during menstruation or the puerperium, and prolonged retention of the sponge may additionally increase toxic shock syndrome risk. As with all contraceptives, risks must be balanced against benefits.

Adolescent↗
PubMed1985

A potential use of the National Death Index for postmarketing drug surveillance.

A particularly difficult problem for both the Food and Drug Administration and the pharmaceutical manufacturer is evaluation of the importance of spontaneous reports of suspected drug-associated fatalities. These reports are rare, and usually no accurate denominator data on drug use exist. This article proposes that the National Death Index be used to calculate mortality rates for selected drugs as part of the postmarketing surveillance efforts of the government and manufacturers. When hypotheses are generated from spontaneous reports and/or the mortality data, additional studies can be conducted on the cohorts that were identified for mortality follow-up.

Death Certificates↗
PubMed1983

Relationship of oral contraceptive estrogen dose to age.

The authors analyzed extracts of the computerized Medicaid records of 81,968 patients with prescription billing claims for oral contraceptives from the states of Michigan and Minnesota in 1980. It was found that women aged 35-39 years were more than twice as likely to be recipients of high dose (over 50 micrograms) estrogen oral contraceptive preparations than women aged 15-19. There was an increase in the proportion of high dose estrogen recipients among oral contraceptive recipients for each successive five-year age group from 15-19 to 35-39 years in both states. These findings were similar to those from National Disease and Therapeutic Index data for the United States for 1980, and appear to indicate changing patterns of use in the past decade. The independent contributions of age and estrogen dose or their combined effect with respect to the risk for venous thrombosis, pulmonary embolism, or related diseases has not been assessed in prior studies. To the extent that current use of oral contraceptives with higher estrogen doses contributes to the age-related trend of morbidity and mortality rates among women aged 15-44 years, an opportunity for prevention exists by altering this pattern of use.

Adolescent↗
PubMed1978

Case-control studies: a sequential approach.

A sequential approach to the design of a matched pair case-control study is proposed as an alternative to fixed sample plans when information on case-control pairs is acquired sequentially in time. The method described is that of Wald using the Sequential Probability Ratio Test (SPRT) for comparing two binomial populations. The test is an open, non-truncated procudure. Several tables are presented for the average sample numbers needed under the sequential plan and fixed sample plan for selected Type 1 and 2 errors, alternative relative risks of interest and exposure probabilities in case and controls. A hypothetical example is presented to illustrate the use of the method and discussion is given as to the possible advantages and disadvantages of the sequential approach to case-control studies.

Epidemiologic Methods↗
PubMedDate not supplied

Emerging and recurrent issues in drug development.

This paper reviews several emerging and recurrent issues relating to the drug development process. These emerging issues include changes to the FDA regulatory environment, internationalization of drug development, advances in computer technology and visualization tools, and efforts to incorporate meta-analysis methodology. Recurrent issues include: renewed interest in statistical methods for handling subgroups in the design and analysis of clinical trials; renewed interest in alternatives to the 'intention-to-treat' analysis in the presence of non-compliance in randomized clinical trials; renewed interest in methodology to address the multiplicities resulting from a variety of sources inherent in the drug development process, and renewed interest in methods to assure data integrity. These emerging and recurrent issues provide a continuing challenge to the international community of statisticians involved in drug development. Moreover, the involvement of statisticians with different perspectives continues to enrich the field and contributes to improvement in the public health.

Computer-Aided Design↗
PubMedDate not supplied

Balancing demands of cancer surveillance among survivors of thyroid cancer.

PURPOSE: The purpose of this qualitative study was to explore and describe the demands of long-term cancer surveillance among survivors of thyroid cancer and how these perceived demands influence their quality of life. DESCRIPTION OF STUDY: The sample consisted of 34 participants who had undergone thyroid hormone withdrawal before body scanning for evaluation of cancer recurrence and/or metastatic disease. Participants completed two self-report instruments: 1) a Demographic Data Tool, and 2) three open-ended questions about quality of life during thyroid hormone withdrawal. The participants wrote down their answers to the demographics and open-ended questions. RESULTS: The 34 participants had a mean age of 40 years (range, 22-73 years); 85% were women and 74% were white. All were high school educated, and 32% were college graduates. Sixty-eight percent were married, and 75% were employed either full- or part-time. Participants experienced profound changes in relationship to withdrawal from thyroid hormone medication. These changes in physical well-being coupled with the potential for disease recurrence influenced their psychological and social well-being. Balancing the demands of cancer surveillance (through body scanning and thyroid hormone withdrawal) against day-to-day living had a major influence on perceptions of quality of life. CLINICAL IMPLICATIONS: Study results support other studies and clinical reports that physical symptoms related to thyroid hormone withdrawal were profound, severe, and debilitating. First, participants with thyroid cancer had to learn through their own personal experiences what physical limitations were imposed during the period of surveillance testing. Second, the physical changes and anticipation of body scanning exerted a profound effect on psychological and social well-being. Feelings of loss, anxiety, depression, and loss of concentration were very difficult to endure. Third, given the general characteristics of this population of thyroid cancer survivors who generally are younger and working, the experience of hypothyroidism can have a major impact on work schedules. Individuals who require a large amount of concentrated attention to work tasks may need to modify their work schedules during hypothyroid states. Findings suggest that individuals who are considered "cured" of their disease are a largely forgotten segment of cancer survivors. However, participants in this study continued to inform us of the process of cancer survivorship and the need for exploring quality-of-life concerns, regardless of prognosis.

Adult↗