Biomedical subjects

C F Pieper

Publications and source records attributed to C F Pieper.

At least 55 records · Page 3Linked to original sources

PubMed1998

Predictors of short-term changes in serum intact parathyroid hormone levels in hemodialysis patients: role of phosphorus, calcium, and gender.

Several factors have been identified as important in the pathogenesis of secondary hyperparathyroidism in end-stage renal disease, including serum calcium, phosphorus, and calcitriol. To examine the independent effects of key factors, we prospectively studied 52 new hemodialysis patients with mild secondary hyperparathyroidism (PTH, 110-670 pg/mL) treated with a standardized regimen of calcium supplements, phosphorus binders, and no vitamin D derivatives. We used simple and multivariable linear regression analysis to examine the relationship between changes in PTH (deltaPTH) levels observed over a 4-week period and various biochemical and demographic variables. By simple linear regression we found that changes in serum phosphorus (r2 = 0.31; beta = 41.6; P = 0.0001), initial phosphorus concentration (r2 = 0.15; beta = 33.4; P = 0.005), initial PTH level (r2 = 0.29; beta = 0.58; P = 0.0001), changes in serum calcium (r2 = 0.12; beta = -74.0; P = 0.01), and gender (r2 = 0.07; beta = 76.1; P = 0.05) were significantly associated with deltaPTH. However, upon multivariable regression analysis, only the changes in phosphorus (partial r2 = 0.31; beta = 37.0; P = 0.0001), initial PTH level (partial r2 = 0.23; beta = 0.50; P = 0.0001), and gender (partial r2 = 0.05; beta = 63.1; P = 0.02) remained significantly associated with deltaPTH. Neither the serum concentration of 1,25-dihydroxyvitamin D3, bicarbonate, aluminum, or albumin nor changes in the serum bicarbonate concentration, the presence of diabetes, KT/V, or age were significantly associated with the deltaPTH. Our findings are consistent with independent effects of phosphorus and gender on parathyroid gland function in patients with dialysis-dependent renal failure through mechanisms that remain to be defined.

Adult↗

PubMed1998

Cerebral infarcts in patients with autopsy-proven Alzheimer's disease: CERAD, part XVIII. Consortium to Establish a Registry for Alzheimer's Disease.

OBJECTIVE: To study the relation between cerebral infarction and clinical and neuropsychologic manifestations in patients with autopsy-proven Alzheimer's disease (AD) enrolled in the Consortium to Establish a Registry for Alzheimer's Disease (CERAD). BACKGROUND: Prior studies report that subjects with neuropathologic evidence of AD and concomitant brain infarcts had poorer cognitive function and higher frequency of dementia than those with AD alone. METHODS: Clinical and neuropsychologic manifestations of dementia were studied in 74 subjects with neuropathologic findings of AD alone and 32 with AD and concomitant cerebral infarcts or lacunar lesions. RESULTS: The 32 patients with both AD and vascular lesions were significantly older at time of death (median age, 81 years) than the 74 patients with AD alone (76 years; p = 0.02). At the final follow-up visit, the severity of the dementia was greater in AD patients with vascular lesions (median Clinical Dementia Rating [CDR] = 3) than in those with AD alone (CDR = 2; p = 0.03). Patients with AD and vascular lesions performed significantly worse on verbal fluency, Boston Naming, and Mini-Mental State Examination (MMSE) tests. No differences between the groups were observed, however, in the semiquantitative measures of frequency of neuritic plaques or neurofibrillary tangles. CONCLUSIONS: The clinical-neuropathologic correlations in CERAD patients generally confirm those in prior studies, indicating that the presence of cerebral infarction in patients with AD is associated with greater overall severity of clinical dementia and poorer performance on specific tests of language and cognitive function.

Aged↗

PubMed1997

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.

Acute Disease↗

PubMed1997

Psychosocial and physical correlates of chronic depression.

This study used a case-control design to address differences in psychosocial, physical and clinical profiles between subjects who presented with a chronic index episode of major depression and those who presented with a non-chronic index episode. Subjects were adult patients participating in the Duke University Mental Health Clinical Research Center (MHCRC) for the Study of Depression in Later Life. Cases (N = 88) who reported duration of depressive symptoms lasting > or = 24 months at enrollment were compared to controls (N = 354) who reported symptoms lasting 1-12 months. The groups were compared with respect to selected demographic and clinical variables, physical function deficits, medical comorbidity, social support constructs and number of recent stressful life events. Social support and physical health were more relevant to chronicity of major depressive illness than were severity of illness or family history. Older age (> 60 years) intensified the deleterious effect of recent negative life events and reduced the deleterious effect of functional impairment on chronic major depression. These findings require special emphasis where treatment for chronic major depression is divorced from considerations of the social environment and functional capacity.

Activities of Daily Living↗

PubMed1997

Psychosocial correlates of job strain in a sample of working women.

BACKGROUND: This study identifies potential mediators of job strain effects on health by determining whether psychosocial factors known to predict an increased risk of cardiovascular disease and all-cause mortality are higher among women who report high levels of job strain. METHODS: Measures of job strain and other psychosocial risk factors were obtained in a sample of 152 female employees of a local corporation. Canonical correlation and analyses of covariance were used to assess relationships between job demands and decision latitude and other psychosocial risk factors. RESULTS: A significant (P = .002) solution to the canonical correlation analysis showed that high job demands and low decision latitude were correlated with a pattern of psychosocial factors consisting of (1) increased levels of negative emotions like anxiety, anger, depression, and hostility; (2) reduced levels of social support; and (3) a preponderance of negative compared with positive feelings in dealings with coworkers and supervisors. This pattern was confirmed by analyses of covariance that adjusted for demographic and specific job characteristics. CONCLUSIONS: The canonical correlation analysis results provide empirical support for the job strain construct. The most important finding is that health-damaging psychosocial factors like job strain, depression, hostility, anxiety, and social isolation tend to cluster in certain individuals.

Adult↗

PubMed1997

Relation of prescription nonsteroidal antiinflammatory drug use to cognitive function among community-dwelling elderly.

PURPOSE: To evaluate the relationship of nonsteroidal antiinflammatory drug (NSAID) use to level of cognitive function in community-dwelling elderly persons. METHODS: The prospective cohort study included 2765 nonproxy subjects from the Duke University Established Populations for Epidemiologic Studies of the Elderly who were cognitively intact at baseline (1986-1987) and alive at follow-up three year later. Cognitive function was assessed by the Short Portable Mental Status Questionnaire (i.e., intact vs. impaired and change in score) and by the individual domains of the Orientation-Memory-Concentration Test (i.e., number of errors). NSAID use, determined from in-home interviews, was coded for chronicity, dose, frequency of use, and prescription status. RESULTS: After controlling for demographic factors as well as health status and behavior, continuous, regularly-scheduled, prescription use of NSAID was associated with preservation of one aspect of cognitive functioning: concentration (beta coefficient, 0.29; 95% confidence interval [CI] -0.54 to -0.04, indicating fewer errors). However, no consistent dose-response relationship was found. Current and prior NSAID use was unrelated to level of cognitive functioning across all five measures; among current users, those taking moderate or high doses (beta coefficient, 0.41; 95% CI, 0.08 to 0.74) made more errors on the memory test compared with those taking low doses (beta coefficient 0.03; 95% CI, -.85 to 0.91). CONCLUSIONS: These results suggest no substantial or consistent protective effect of prescription NSAID use on cognitive function in community-dwelling elderly. However, recent use at higher doses may be associated with memory deterioration in this population.

Aged↗

PubMed1997

The association of plasma IL-6 levels with functional disability in community-dwelling elderly.

BACKGROUND: IL-6 is a multifunctional cytokine that has been shown to increase with age. METHODS: Plasma IL-6 was measured by ELISA in 1,727 community-dwelling elderly subjects whose blood was drawn during the third in-person survey of the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE). Demographics, functional status (disability), and disease states were determined. Correlations of these factors with IL-6 were analyzed with Spearman's Rho while differences between groups were assessed by Wilcoxon test. RESULTS: IL-6 levels were higher with age (p = .0001) even in this older population (> 70 years). There was a positive correlation between IL-6 and functional disability for each of the functional status measures (p = .0001), as well as a correlation between self-rated health and IL-6. Significantly higher median levels of IL-6 were found in subjects reporting prevalent cancer, heart attack, and high blood pressure, but not diabetes or arthritis. The association between age and functional status with high IL-6 remained when all other variables were controlled, in multivariable analysis. CONCLUSIONS: This association between increased plasma IL-6 levels and functional status suggests that dysregulation of IL-6 may be related to the functional disability seen with aging, and that IL-6 may be useful as a component of an overall marker of health.

Aged↗

PubMed1997

Relationship of body mass index to subsequent mortality among seriously ill hospitalized patients. SUPPORT Investigators. The Study to Understand Prognoses and Preferences for Outcome and Risks of Treatments.

OBJECTIVE: To determine if body mass Index (BMI = weight [kg]/height [m]2), predictive of mortality in longitudinal epidemiologic studies, was also predictive of mortality in a sample of seriously ill hospitalized subjects. DESIGN: Prospective, multicenter study. SETTING: Five tertiary care medical centers in the United States. PATIENTS: Patients > or = 18 yrs of age who had one of nine illnesses of sufficient severity to anticipate a 6-month mortality rate of 50% were enrolled at five participating sites in the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were asked their current height and weight as part of the demographic data. Stratifying body mass index by percentile rank (< or = 15, 15 to 85, and > or = 85th percentiles), risk ratios for mortality were calculated by Cox Proportional Hazards using the 15th to 85th percentile of body mass index as the reference group while controlling for multiple variables such as prior weight loss, albumin, and Acute Physiology Score. A body mass index in the < or = 15th percentile was associated with an excess risk of mortality (risk ratio = 1.23; p < .001) within 6 months. High body mass index (> or = 85th percentile) was not significantly related to risk of mortality. CONCLUSIONS: Body mass index, a simple anthropometric measure of nutrition employed in community epidemiologic studies, has now been demonstrated to be a predictor of mortality in an acutely ill population of adults at five different tertiary centers. Even when controlling for multiple disease states and physiologic variables and removing from the analysis all patients with significant prior weight loss, a body mass index below the 15th percentile remained a significant and independent predictor of mortality. Examination of patient vs. proxy data did not change the results. Future studies examining variables predictive of mortality should include body mass index, even in acutely ill populations with a poor probability of survival.

APACHE↗

PubMed1997

Depression in medically ill hospitalized older adults: prevalence, characteristics, and course of symptoms according to six diagnostic schemes.

OBJECTIVE: The purpose of this study was to examine and compare rates of depression, correlates, and course of symptoms in medically ill hospitalized elders through use of six diagnostic schemes (inclusive, etiologic, exclusive-inclusive, exclusive-etiologic, substitutive-inclusive, and substitutive-etiologic). METHOD: A consecutive series of 460 cognitively unimpaired patients aged 60 or over who were admitted to the medical inpatient services of Duke Hospital underwent a structured psychiatric evaluation administered by a psychiatrist. Patients with depression were contacted by telephone at 12-week intervals after discharge to assess weekly change in depressive symptoms (median follow-up time = 47 weeks). RESULTS: The prevalence of major depression varied from 10% to 21% depending on diagnostic scheme; similarly, minor depression varied from 14% to 25%. Diagnostic strategy made little difference in known psychological and health characteristics of patients with depression (predictive validity) or severity of depressive symptoms (convergent validity). The diagnostic strategy that best distinguished a severe and persistent major depression was the exclusive-etiologic approach; however, this strategy missed 49% of patients with major depression identified by the inclusive approach, almost 60% of whom continued to experience persistent symptoms of depression many weeks after discharge. CONCLUSIONS: Diagnostic strategy affects rates of major and minor depression, with about a twofold difference between the extremes. There is little reason, however, to choose one diagnostic scheme over another in all cases. Diagnostic strategy should be chosen on the basis of the specific goals and purposes of the examiner. While the exclusive-etiologic approach identifies the most severe and persistent depressions, the inclusive approach is the most sensitive and reliable approach and is an intermediate predictor of persistent depression.

Adult↗

PubMed1997

Peyronie's disease is associated with Paget's disease of bone.

Peyronie's disease is an idiopathic disorder in which an inflammatory fibrosis occurs in the tunica albuginea of the corpora cavernosa which causes the erect penis to become deformed. Peyronie's disease has a prevalence of 1% in men over age 50 years. Paget's disease of bone is a chronic skeletal disease with areas of increased bone turnover leading to pain, deformity, and in some cases arthritis. Because of a high rate of Peyronie's disease in subjects in a Paget's disease industry-sponsored drug trial, we asked whether there was an association between Peyronie's disease and Paget's disease of bone. We evaluated 61 men with Paget's disease attending our clinic for metabolic bone disease in a tertiary referral hospital, reviewed hospital records of all men discharged from our three hospitals with the diagnosis of Peyronie's disease, and mailed a validated questionnaire about shape of the erect penis to 1500 male members of the Paget Foundation. In the clinic population of men with Paget's disease of bone, 51 of 61 (83.6%) reported having normal erections; 10 patients (16.4%) were impotent. Sixteen of the 51 men (31.4%) had developed a bend or deformity in their erect penis which was confirmed by a urologist's examination to be Peyronie's disease. When the men with Paget's disease with and without Peyronie's disease were compared, there was no difference in their ages, years with Paget's disease, or serum alkaline phosphatase level. Upon medical record review, 1 patient of 262 (0.4%) with Peyronie's disease was found to have Paget's disease of bone. The men with Paget's disease returned their questionnaires for a response rate of 44.8% and reported Peyronie's disease with a prevalence of 14.5%. We suggest that Peyronie's disease is associated with Paget's disease of bone. Furthermore, we suggest that Peyronie's disease may be a previously unrecognized complication of Paget's disease of bone.

Aged↗

PubMed1996

Paget's disease of bone and quality of life.

Little is known about how Paget's disease of bone affects quality of life. To better understand the relative impact of factors on quality of life, we mailed a brief survey to 2000 people randomly selected from the Paget's Foundation mailing list. The sample was geographically stratified to examine the effects of specialist availability. Nine hundred and fifty-eight persons responded to the questionnaire (53% response rate after adjustment for death, incorrect addresses, and nondeliverable mailings). The sample had equal proportions of males and females, with a mean age of 74 years (SD = 9.0). Most (97%) were white, with high levels of education (mean 13 years; SD 3.7) and income (60% earned more than $20,000 annually). They reported pagetic bone in the skull (34%), spine (35%), pelvis (49%), and leg (48%). The most frequently mentioned complications were hearing loss (37%) and bowed limbs (31%). Comorbidity included arthritis (64%), hypertension (32%), and heart problems (28%). Nearly half (47%) reported feelings of depression, and 42% said that their health was fair or poor. Only 21% reported that quality of life was very good or excellent. In multiple partial F-test regression analyses, variables were divided into four domains (social, psychological, care, and biomedical). The psychological domain explained 19% of the variance beyond that explained by all other variables; the social domain explained 3%, the biomedical domain explained 3% and the care domain explained 1%. The importance of the psychological aspects of Paget's disease suggests that treatment protocols should include psychological intervention to improve quality of life.

Adaptation, Psychological↗

PubMed1996

Job stress and preeclampsia.

We conducted a case-control study to determine whether job strain (or stress) during pregnancy resulted in an increased risk of preeclampsia. We compared 110 nulliparous Caucasian and African-American women who had preeclampsia with 115 healthy nulliparous controls. All subjects gave birth between 1984 and 1987 in Chapel Hill, NC. Occupation was ascertained during a telephone interview. We assigned each job title a strain (or stress) score in accordance with the occupational database developed by Karasek. Overall, 54 (49%) of the control women worked during pregnancy, 14 in high-stress jobs. Logistic regression analysis indicated a 3.1-fold [95% confidence interval (CI) = 1.2-7.8] increased risk of preeclampsia for women employed in high-stress jobs (high psychological demand, low decision latitude) and an odds ratio of 2.0 (95% CI = 1.0-4.3) for low-stress jobs compared with nonworking women, while simultaneously adjusting for age, race, family history of preeclampsia, history of hypertension in the subject's mother, gravidity, smoking during pregnancy, timing of the first prenatal visit, and type of birth control used by the couple before the pregnancy. Furthermore, working women had 2.3 times the risk of developing preeclampsia (95% CI = 1.2-4.6) compared with nonworking women. Work-related psychosocial strain increased the risk of preeclampsia in our study.

Adolescent↗

PubMed1996

Five-year performance trends for older exercisers: a hierarchical model of endurance, strength, and flexibility.

OBJECTIVE: To examine 5-year trends in measures of physical performance, and the impact of disease upon performance, in three domains: cardiovascular fitness, musculo-skeletal strength, and flexibility among older adults participating in a medically supervised exercise program. DESIGN: Longitudinal analyses of data obtained in an observational cohort study. SETTING: Department of Veterans Affairs Medical Center in Durham, North Carolina. PARTICIPANTS: Seventy-three community-dwelling veterans between 64 and 90 years of age. INTERVENTION: Voluntary participation in a medically supervised outpatient exercise program meeting 3 days per week for 90 minutes per session. MAIN OUTCOME MEASURES: Changes over time in cardiovascular fitness, musculoskeletal strength, and flexibility. RESULTS: Forty-nine percent of the original study participants remained in the program for a full 5 years. They had lower baseline rates of cardiorespiratory and musculoskeletal diseases than did the dropouts. Dropouts were significantly more impaired in baseline measures of cardiovascular fitness (P = .038) and strength (P = .007). Changes over time for cardiovascular fitness and strength were similar. Only linear (P < .05) and quadratic time (P < .001) were significant. Only linear time was significant for measures of flexibility (P < .05). Baseline cardiorespiratory disease, baseline musculoskeletal disease, and interaction terms were not significant. Overall, measures of physical performance demonstrated gradual improvement for 2 to 3 years, followed by a gradual decline in performance irrespective of baseline disease status. CONCLUSION: Older adults who exercise regularly, including those with multiple chronic diseases, can achieve significant gains in measures of physical performance, and these gains can be sustained for 2 to 3 years.

Aged↗

PubMed1996

Risk factors for nosocomial pneumonia: comparing adult critical-care populations.

The purpose of the study was to examine risk factors for nosocomial pneumonia in the surgical and medical/respiratory intensive care unit (ICU) populations. In a public teaching hospital, all cases of nosocomial pneumonia in the surgical and medical/respiratory ICUs (n = 20, respectively) were identified by prospective surveillance during a 5-yr period from 1987-1991. Each group of ICU cases was compared with 40 ICU control patients who did not acquire pneumonia, and analyzed for 25 potential risk factors. Surgical ICU patients were found to have consistently higher rates of nosocomial pneumonia than medical ICU patients (RR = 2.2). The strongest predictor for nosocomial pneumonia in both the surgical and medical/respiratory ICU groups was found to be prolonged mechanical ventilation (> 1 d) resulting in a 12-fold increase in risk over nonventilated patients. APACHE III score was found to be predictive of nosocomial pneumonia in the surgical ICU population, but not in the medical/respiratory ICU population. We conclude that certain groups deserve special attention for infection control intervention. Surgical ICU patients with high APACHE scores and receiving prolonged mechanical ventilation may be at the greatest risk of acquiring nosocomial pneumonia of all hospitalized patients.

APACHE↗

PubMed1996

Do racial differences in hypertension persist in successful agers? Findings from the MacArthur Study of Successful Aging.

The objective of this study was to determine whether racial differences in hypertension in a random sample of community-dwelling older adults also remained significant in a sample of successful agers. Data for the random sample of community-dwelling older adults came from the Duke University Established Populations for Epidemiologic Studies of the Elderly (4,162 community-dwelling adults age 65 and older) and showed strong racial differences in hypertension. Data for successful agers came from the Duke MacArthur (428 of EPESE respondents in the top 30% in terms of physical, cognitive, and psychosocial performance). The mean of two sitting blood pressure measurements was the dependent variable for both sets of analyses. Independent variables included demographics and health factors. Using logistic regression, odds ratios in the Duke EPESE and Duke MacArthur samples for race were similar (Duke EPESE odds ratio = 1.30; Duke MacArthur odds ratio = 1.29). Sample size differences affected statistical significance. However, race differences in hypertension in older adults appear to be unexplained by socioeconomic status or other usual explanatory variables. Even among successful agers, racial differences in hypertension persist.

Aged↗

PubMed1995

Racial differences in the occurrence of herpes zoster.

The purpose of this study was to determine if there are racial differences in the occurrence of herpes zoster (shingles). The study population was the Duke Established Populations for Epidemiologic Studies of the Elderly, a probability sample of community-dwelling persons > 64 years old in North Carolina. Interviewers administered a comprehensive health survey to the participants that included questions about lifetime occurrence of shingles. Of the 3206 subjects, 316 (9.9%) had had zoster: 81 (4.5%) of 1754 blacks and 235 (16.1%) of 1452 whites had had shingles (P < .0001). After controlling for age, cancer, and demographic factors, blacks remained one-fourth as likely as whites (adjusted odds ratio 0.25, 95% confidence interval 0.18-0.35; P = .0001) to have experienced zoster. In summary, blacks had a significantly lower risk of developing herpes zoster than whites, a new finding in herpes zoster epidemiology.

Age Factors↗

PubMed1995

Functional and mobility impairments associated with Paget's disease of bone.

OBJECTIVE: To determine if patients with Paget's disease of bone involving the tibia, femur, and/or acetabular portion of the ilium had more impairments in function and mobility than age- and sex-matched control subjects. PATIENTS AND METHODS: A case control study with Paget's disease patients selected from a center for bone disease at a tertiary medical center; control subjects were volunteers from the Duke University Aging Center subject registry. Demographic characteristics, physical examination and serum alkaline phosphatase levels were obtained. Radiographs of the pelvis and lower extremities were evaluated by a radiologist. All participants completed a Functional Status Questionnaire (FSQ). Mobility measures included mobility skills protocol, 10-foot walk time, 360-degree turn left (number of steps), and 6-minute walk distance. RESULTS: The 12 Paget's disease patients were no different in age (70.7 +/- 6.2 years) than the 12 control subjects (69.5 +/- 6.2 years). Serum alkaline phosphatase levels were elevated in Paget's patients (539 +/- 530 IU/L), and normal in control subjects (85 +/- 17 IU/L). In addition to Paget's disease, radiographs showed joint space loss in joints proximate to the diseased bone. On the FSQ scales Paget's disease patients had significantly lower scores in basic activities of daily living (P < .05), instrumental activities of daily living (P < .001), and social activity than control subjects (P < .05). There was no difference between the groups on scales measuring mental health and quality of social interaction. On mobility measurements, Paget's disease patients showed significant impairments when compared with control subjects: mobility skills protocol score (22.5 +/- 2.5 vs 25.6 +/- 0.7, P < .001); 10-foot walk (3.96 +/- 1.3 vs 2.55 +/- 0.5 seconds, P < .001); 360 degree turn left (8.0 +/- 1.0 vs 5.9 +/- 0.6 steps, P < .001); and 6-minute walk (342.0 +/- 108.5 vs 519.4 +/- 100 meters, P < .001). CONCLUSION: When compared with control subjects, patients who have Paget's disease of bone involving the tibia, femur, or acetabular portion of the ilium have clinically and statistically significant functional and mobility impairments compared to age- and gender-matched controls.

Activities of Daily Living↗

PubMed1995

Improved spatial resolution for cardiac mapping using current source density-based electrode arrays.

The time of the minimum slope (i.e., the fastest negative deflection) in monopolar (MP) electrograms from normal hearts compares closely with time of phase 0 of the action potential in cells underlying the electrode, but poor rejection of far-field activity may limit the utility of MP electrode technology in dense arrays used for the study of ventricular tachycardia and fibrillation. The purpose of this study is to evaluate more myopic discrete bipolar (BP) and nondirectional, two-dimensional current source density (CSD) based arrays for rejection of far-field potentials and precision of activation time determination. Simultaneous recordings of the CSD, MP, and multiple BP electrograms were performed on normal dog epicardium. The time of the minimum slope in MP electrograms was compared to activation times in CSD and BP derivations using: (1) peak; (2) steepest slope; (3) zero crossing of the steepest sloping segment in either direction; and (4) waveform morphology. In vivo, CSD amplitude was reduced significantly more than MP and BP amplitudes by insertion of inert media between the heart and the electrodes. The time of the steepest slope in CSD electrograms designated activation times closest to the time of the minimum slope in MP electrograms (0.9 +/- 1.3 msec). We conclude that CSD provides a nondirectional electrode system that accurately defines the time of local activation and possesses better spatial specificity than MP electrode systems and BP electrode systems having the same interelectrode distances.

Animals↗