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Biomedical subjects

D Iverson

Publications and source records attributed to D Iverson.

18 recordsLinked to original sources
PubMed2004

Trial of print and telephone delivered interventions to influence walking.

BACKGROUND: Both self-help print materials and telephone-assisted counseling have generally proved useful strategies to increase physical activity. This study examined their effectiveness in an intervention aimed specifically at promoting walking for specific purposes. METHODS: Participants (n = 399) were randomly allocated to one of two 3-week intervention programs. The Print program comprised multiple mailing of brochures that emphasized walking within the local community environments. The Print plus Telephone program received the same brochures plus three telephone calls. Data collected via mailed self-completed surveys were analyzed by exploring outcomes related to walking for specific purposes. RESULTS: There were no significant differences between the two programs in any of the walking measures. Both groups significantly increased time reported walking for exercise per week [Print: t(1,277) = -3.50, P < 0.001; Print plus telephone: t(1,106) = -2.44, P < 0.016]. Significantly, more participants in the Print plus Telephone group reported receiving and reading the materials (chi2 = 20.11, P < 0.0001). CONCLUSIONS: The intervention programs were more successful at increasing walking for exercise than for any other purpose. The addition of brief telephone support was successful in focusing participants' attention on the print materials, but did not result in any additional increase in walking.

Adult↗
PubMed1999

US neurologists in the 1990's: trends in practice characteristics.

BACKGROUND: The American Academy of Neurology (AAN) conducts periodic surveys of its members to profile and monitor changes in the characteristics of US neurologists and their practices. OBJECTIVE: To assess neurologists' characteristics, geographic distribution, practice arrangements, professional activities, practice volume, procedures performed, sources of revenue, involvement with managed care and capitation, and other selected topics. METHODS: The AAN Member Census survey was sent to US neurologists in the fall of 1996 (response rate = 89%), and the Practice Profile survey was sent to a random sample of 1,986 US neurologists in the summer of 1997 (response rate = 55%) who had completed a Member Census survey. The results of the Practice Profile survey were compared with those of two prior surveys conducted in 1991 to 1992 and 1993 to 1994. RESULTS: The mean age of US neurologists is 48 years, 18% are women, 93% are US citizens, and 24% are international medical graduates. The proportion of neurologists in solo practices, group practices, and medical schools/universities has not changed. The weekly hours worked has remained stable (58 hours), but the time spent in administrative activities has increased (p < 0.001). The average number of patient visits per week to neurologists appears to have increased (p < 0.001), as has the proportion of neurologists performing procedures (p < 0.05). The majority of neurologists have contracts with managed care organizations (82%), and a minority (32%) have capitated payment arrangements. Medicare continues to be the largest source of clinical revenue. Nearly 50% of all respondents have experience in developing clinical practice guidelines or critical pathways, and >20% of respondents employed physician extenders to assist in their practices. CONCLUSION: Neurologists are spending more time in administrative activities, are performing or interpreting more procedures, and are seeing more patients. Neurologists' involvement with capitation is comparable with that in a nationally representative sample of physicians, and they are exploring innovative ways, such as developing practice guidelines and using physician extenders, to improve the quality and efficiency of providing neurologic care.

Adult↗
PubMed1999

Communication between family physicians and oncologists: qualitative results of an exploratory study.

OBJECTIVE: To study communication between family physicians (FPs) and oncologists, and to look at the factors that may influence FP involvement in cancer care. DESIGN: This survey design uses a qualitative methodology, where the data are analyzed using a modified grounded theory approach. SETTING: This was a multisite study using 14 focus groups of FPs, followed by structured telephone interviews with 116 FPs in 6 different Canadian provinces. MAIN OUTCOME MEASURE: Interview questions were used to explore the actual and desired roles of FPs in cancer care, and the quality of communication with oncologists with reference to a particular cancer patient in the FPs' practice. RESULTS: Physicians providing cancer care must consider complex psychosocial and biomedical factors, more so than with other chronic diseases, and so written communication alone is inadequate. Family physicians require face-to-face and/or telephone communication with the oncologist to negotiate their respective roles, and to discuss the patient's prognosis and the effectiveness of proposed treatments. Family physicians expressed a desire to become more involved in all stages of cancer care in both the biomedical and psychosocial aspects, and to help better define their roles throughout the illness trajectory. CONCLUSION: These results suggest opportunities to improve the communication, coordination and comprehensiveness of shared cancer care provided by family physicians and oncologists in different clinical settings.

Canada↗
PubMed1995

Do we practice what we preach? Comparing the patients of faculty and residents.

BACKGROUND AND OBJECTIVES: In academic family practice centers, the distribution of patients between faculty and residents influences the educational milieu. The medical literature has rarely addressed the differential case mix within the ambulatory medical educational setting. The goal of this study was to compare the characteristics of patient visits to resident and faculty physicians in seven community-based, university-affiliated family practice programs. METHODS: Using the National Ambulatory Care Survey instrument and protocol, 98 faculty and resident physicians recorded their ambulatory patient visits for one randomly selected week between July 1991 and June 1992 (n = 1,498). RESULTS: Patients of resident physicians were younger, more likely to be nonwhite (21.7% vs 9.8%, P < .001), and more likely to be reimbursed by Medicaid (34.2% vs 14.3%, P < .001) than patients of faculty physicians. Despite these patient differences, the spectrum of clinical problems was similar. There were minimal differences in the delivery of diagnostic services and therapeutic services. CONCLUSIONS: The patients seen by residents and faculty differ in important demographic characteristics. These differences could adversely affect the education of resident physicians. Academic family practice centers should actively monitor the age/gender/payment profile of resident and faculty patient panels and assign patients to achieve a desirable case mix for resident education. The differential racial distribution of faculty and resident visits suggests an unidentified systematic bias in patient assignment that warrants further investigation.

Academic Medical Centers↗
PubMed1994

Falls on a neurorehabilitation unit: reassessment of a prevention program.

We conducted a retrospective case-control study of falls over a four year period on a 30 bed neurorehabilitation unit at the Burke Rehabilitation Hospital to characterize the nature of falls and identify factors associated with falling. The most common diagnoses treated on the unit were traumatic spinal cord injury, brain injury, and multiple sclerosis; stroke patients are treated on another service. Falls represented 72 percent of all incident reports made to the Nursing Office during the study period. One hundred seventeen (117) falls occurred in 82 patients during a time when the unit census was 28,622 patient days, yielding a rate of 1,439 falls per 1,000 patient years. One hundred fourteen (114) patients admitted with no history of falling during the same period were selected randomly for comparison. Most falls were associated with no injury (n = 96) or minor injury (n = 18). The most significant injuries occurred in three cases with lacerations requiring sutures. Falls occurred with greatest frequency during the first and fourth quartiles of the hospital stay, during the evening and while bed transfers were being performed. No association between falling and patient age, sex, diagnosis, number of medications, use of sedating medications, presence of motor, visual or cognitive impairment or orthostatic hypotension was evident. An increased risk of falling was associated with physician orders for Posey restraints. The implication of these findings for falls prevention programs is discussed.

Accidental Falls↗
PubMed1990

Analysis of the costs of a large prevention trial.

Total direct costs of the Women's Health Trial (WHT), a large multicenter prevention trial, were reduced by more than 50% by means of research cost analysis conducted during the trial design phase. The unit costs of specific trial activities were estimated so that total direct costs of the trial could be predicted from design parameters. The relative costs of screening, treatment, and follow-up, and the fixed costs associated with each clinical center in a multicenter prevention trial were taken into account. Direct costs of the WHT were reduced from +195 million to +95 million by refinement of the trial protocol, selection of an efficient design, and consideration of trial logistics. The analyses suggest several ways to reduce costs in a prevention trial. Use of the case-cohort approach can reduce costs substantially when the protocol includes collection of specimens or data that are costly to process. When establishing and maintaining a clinical center represents a significant proportion of a clinical center's costs, use of a smaller number of larger clinical centers offers important cost savings. Because restrictive eligibility requirements reduce the recruitment potential of each clinical center, use of high-risk participants may not improve the efficiency of a prevention trial; its favorable impact on sample size may fail to compensate for its cost in terms of additional clinical centers and higher recruitment costs.

Aged↗
PubMed1988

Statistical design of the Women's Health Trial.

The National Cancer Institute has initiated a randomized trial to determine whether a low fat diet can reduce the incidence of breast cancer among women at increased risk for this disease. A feasibility trial involving 303 women has been conducted to examine recruitment strategies, study short-term compliance and, more generally, develop and refine trial procedures. The feasibility trial group also developed a detailed full-scale trial design plan, and randomization of participants to such a trial is currently underway. The purpose of this report is to describe the major design features of this Women's Health Trial, with particular emphasis on the statistical aspects of the design. The trial is planned to last 10 years and to include 32,000 participants. Of these 32,000 women, 12,800 will be assigned to a low fat diet intervention, and the other 19,200 will constitute a control group. The sample size of 32,000 arises from a range of estimates and assumptions pertaining to (a) the incidence of breast cancer at enrollment corresponding to selected eligibility criteria, (b) the relative risk of breast cancer as a function of a woman's history of dietary fat intake, (c) compliance assumptions in terms of average percent fat in the intervention and control groups as a function of time from randomization, and (d) rates of competing causes of death. These estimates and assumptions will be discussed, as will the robustness of the intended sample sizes to departures from such design assumptions.

Aged↗
PubMed1984

Towards a molecular and atomic anatomy of calmodulin and calmodulin-binding proteins.

The molecular mechanisms by which calcium regulates cellular processes such as metabolic and mechanochemical events probably involve interactions with a variety of molecules. A large body of evidence suggests that the targets of calcium's regulatory effects inside the cell are calcium-binding proteins. Our work attempts to correlate calcium-binding protein structure with activities. In this chapter we have presented some of our recent studies on these functional domains in calmodulin and calmodulin-binding proteins. Selected chemical modifications of known amino acid sequence positions have demonstrated the presence of multiple functional domains on calmodulin, have allowed the dissociation of calmodulin functions, and have provided the necessary tools for further investigations of the molecular basis of calmodulin action. One of these modifications, iodination of tyrosine-99, has allowed us to develop procedures to reproducibly detect calmodulin-binding proteins by a binding technique. This method is technically simple. It allows us to detect and study calmodulin-binding proteins (e.g., myosin heavy chain and membrane gap junction proteins) that would be difficult to study with immobilized calmodulin. We have developed a library of antibodies to calmodulin and related proteins such as troponin C and S100 beta. Some of these antisera appear to be site-specific gamma globulins. We have demonstrated that reactivity can be contained in an amino acid sequence as short as seven residues. We have demonstrated the feasibility of using an immunochemical mapping approach to study calmodulin and calmodulin-binding proteins. Comparative sequence analyses combined with functional analyses have allowed correlation of function and structure and have suggested logical candidates for functional domains on calmodulin and calmodulin-binding proteins. Although not discussed in detail in this chapter, these calmodulin-binding proteins appear to contain amino acid sequence homologies. This suggests, analogous to the approach used for calmodulin and related proteins, a logical starting point for domain analyses of calmodulin-binding proteins. Interestingly, structural homologies among calmodulin-binding proteins are reminiscent of the different phosphorylation sites found in many of the physiological substrates for protein kinases. Since a number of calmodulin-binding proteins are themselves substrates for protein kinases, these results suggest another possible point of interrelationships between calcium and cyclic nucleotide regulation.

Amino Acid Sequence↗
PubMed1977

Comparison of NADH and NADPH oxidase activities in granules isolated from human polymorphonuclear leukocytes with a fluorometric assay.

A fluormetric method for the determination of pyridine nucleotides has been adapted for use in studying the reduced pyridine nucleotide oxidases in human polymorphonuclear leukocytes. In the presence of strong base the oxidized forms of the pyridine nucleotides form a highly fluorescent product. The small amounts of NAD(P) formed by the oxidase reactions can be determined with great sensitivity. This method has been compared to the radioisotopic assay for NADPH oxidation. Both methods gave essentially the same results in terms of nanomoles NADP produced by control, resting, and phagocytizing samples. Both NADPH and NADH oxidase activities were insensitive to cyanide. NADPH oxidation had a pH optimum of 5.5, while that for NADH appeared to be 6.0. Granules isolated from phagocytizing cells routinely showed more activity toward both substrates (two to threefold) than granules from resting cells. Both activities were located primarily in a granule fraction prepared by differential centrifugation. Oxidation of NADPH was routinely four to five times that of NADH at all except very high substrate levels. Measurable NADH oxidation was rarely seen below 0.80 mM NADH, while NADPH oxidation was easily measurable at 0.20 mM. One patient with chronic granulomatous disease was studied. At low substrate levels, there was no activity toward either substrate in granules isolated from either resting or phagocytizing cells of this patient, while granules isolated from normal control cells showed substantial activity at these substrate levels. Purification of the activities had been initiated with linear sucrose gradients. Both activities co-sediment to a very dense region of the gradient, a region different from that in which membrane or azurophil granules usually equilibrate. The peak gradient fractions show a 10-30-fold increase in specific activity over comparable granule fractions. These data suggest that the oxidase activities are associated with one enzyme that has different affinities for the two substrates ans support the contention that the oxidation of NADPH is responsible for the metabolic burst accompanying phagocytosis in human PMNL.

Eosinophils↗
PubMedDate not supplied

Economic analysis of family practice residency programs: a report from the Northeastern Ohio Network.

BACKGROUND: The financial impact of a family practice residency program on a sponsoring institution is poorly understood. This study intended to describe as fully as possible all the expenses and revenues from five community-based family practice residency programs in northeastern Ohio. METHODS: Direct and indirect expenses, revenues, and demographics were evaluated for 1992. Similarities and differences among the participating programs were examined. RESULTS: Overall expenses per resident were similar in all five programs, with a range from $162,000 to $203,000. Revenues reflected the number of residents in the program, although collection ratios varied. Inpatient collections ranged from 53%-76% and outpatient collections ranged from 60%-76%. An average of 30% of graduates from the past 10 years were on the active medical staff of their sponsoring institution, with a range of 21%-36%. CONCLUSION: Based on the expenses, revenues collected, and reasonable assumptions made about cost of care in the hospital setting, the family practice residencies are probably a break-even operation, excluding the benefit of providing primary care physicians to the community.

Costs and Cost Analysis↗