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Biomedical subjects

L D Fisher

Publications and source records attributed to L D Fisher.

At least 91 records · Page 5Linked to original sources
PubMed1990

Anthropometric and clinical measures as predictors of back pain complaints in industry: a prospective study.

A prospective, longitudinal investigation was conducted to investigate anthropometric and clinical examination measures as predictors of future back pain reports in industry. Associations between these measures and a history of back problems were examined as well. Participants in the study included 3,020 aircraft manufacturing employees who underwent an examination and then were tracked for greater than 4 years for subsequent back pain reports. Back symptoms elicited on straight leg raising (SLR) was the measure most significantly associated with subsequent back pain reporting among both men and women (p less than 0.0001). The only variables to add predictive value in addition to back pain on SLR were age and weight in women, and history of back problems and age in men.

Adult↗
PubMed1990

Correlation of sensory electroneurographic recordings and myelinated fiber diameters of the superficial peroneal nerve of dogs.

The compound nerve action potential (CNAP) of the superficial peroneal nerve of dogs was investigated to determine: (1) the influence of the stimulation technique on the configuration of the CNAP, with particular attention to late components; (2) the fiber diameter (FD) distribution; and (3) the relationship between FD distribution and CNAP configuration, by reconstruction of CNAP made on the basis of FD distributions. The CNAP were evoked in 9 dogs under halothane anesthesia by 2 stimulation methods: percutaneous needle electrode stimulation and direct stimulation of the exposed superficial peroneal nerve. Recordings were made with percutaneous needle electrodes. Full nerve cross sections of 7 superficial peroneal nerves were prepared for FD morphometric analysis. Reconstruction of CNAP were made on the basis of the FD distributions. Late components of the CNAP could be evoked with either stimulation method, but only with a stimulus intensity of 3 to 5 times maximal for the main (early) component of the CNAP. The FD histograms of 7 analyzed nerves had bimodal distribution. In 5 nerves, peaks were at 4.2 to 4.5 microns and 9.0 to 10.0 microns, with 60% of the fibers in the small-diameter group. In 2 nerves with lower maximal conduction velocities, peaks were shifted toward smaller values. The CNAP reconstructions made by use of FD data closely resembled actual recordings when a fifth-order polynomial function was applied to the relationship between nerve conduction velocity and FD. Reconstructions made by use of 1 or 2 linear functions did not accurately resemble actual recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1990

Radionuclide ejection fractions in the evaluation of patients being considered for bone marrow transplantation: risk for cardiac toxicity.

One hundred thirty-six patients underwent radionuclide ventriculography as part of an evaluation prior to bone marrow transplantation. One hundred twenty-six who were considered suitable transplant candidates began conditioning chemotherapy or chemoradiotherapy and were retrospectively evaluated for development of cardiac toxicity. The cumulative pretransplant anthracycline dose in patients who began the conditioning regimen was not a significant predictor for decreased pretransplant ejection fraction (EF) or severe cardiac toxicity following transplantation. Fourteen patients (10%) had EFs less than 50%. Of these, 10 began the preparative regimen and two (20%) experienced grade III or IV cardiac toxicity (95% confidence interval (CI) 2.5-56%) versus five of 116 patients (4%; CI 1.4-9.8%) with EFs greater than or equal to 50% (p = 0.096). The incidence of grade III or IV cardiac toxicity among patients with any history of cardiac dysfunction or with an abnormal physical examination prior to transplant was 9% (two of 22) versus 5% among the remaining patients (five of 104) (p = 0.605). Though transplant-related cardiac toxicity may be more common in patients with mildly reduced EFs, the small number of patients with reduced EFs referred for transplant does not warrant the routine pretransplant screening of all patients with radionuclide ventriculography.

Adolescent↗
PubMed1989

Secondary cancers after bone marrow transplantation for leukemia or aplastic anemia.

To determine the incidence of secondary cancers after bone marrow transplantation, we reviewed the records of all patients at our center who received allogeneic, syngeneic, or autologous transplants for leukemia (n = 1926) or aplastic anemia (n = 320). Thirty-five patients were given a diagnosis of secondary cancer between 1.5 months and 13.9 years (median, 1.0 year) after transplantation. Sixteen patients had non-Hodgkin's lymphomas, 6 had leukemias, and 13 had solid tumors (including 3 each with glioblastoma, melanoma, and squamous-cell carcinoma). There were 1.2 secondary cancers per 100 exposure-years during the first year after transplantation (95 percent confidence interval, 0.7 to 2.0). The rate declined to 0.4 (95 percent confidence interval, 0.2 to 0.7) after one year. The age-adjusted incidence of secondary cancer was 6.69 times higher than that of primary cancer in the general population. In a multivariate model, the predictors (and relative risks) of any type of secondary cancer were acute graft-versus-host disease treated with either antithymocyte globulin (relative risk, 4.2) or an anti-CD3 monoclonal antibody (13.6) and total-body irradiation (3.9). Two additional factors were associated with secondary non-Hodgkin's lymphomas: T-lymphocyte depletion of donor marrow (12.4) and HLA mismatch (3.8). We conclude that recipients of bone marrow transplantation have a low but significant risk of a secondary cancer, particularly non-Hodgkin's lymphoma.

Adolescent↗
PubMed1989

Prognosis in primary biliary cirrhosis: model for decision making.

The ideal mathematical model for predicting survival for individual patients with primary biliary cirrhosis should be based on a small number of inexpensive, noninvasive measurements that are universally available. Such a model would be useful in medical management by aiding in the selection of patients for and timing of orthotopic liver transplantation. This paper describes the development, testing and use of a mathematical model for predicting survival. The Cox regression method and comprehensive data from 312 Mayo Clinic patients with primary biliary cirrhosis were used to derive a model based on patient's age, total serum bilirubin and serum albumin concentrations, prothrombin time and severity of edema. When cross-validated on an independent set of 106 Mayo Clinic primary biliary cirrhosis patients, the model predicted survival accurately. Our model was found to be comparable in quality to two other primary biliary cirrhosis survival models reported in the literature and to have the advantage of not requiring liver biopsy.

Decision Making, Computer-Assisted↗
PubMed1989

Primary sclerosing cholangitis: natural history, prognostic factors and survival analysis.

The natural history of primary sclerosing cholangitis was assessed in 174 patients; 37 were asymptomatic and 137 had symptoms related to underlying liver disease. At the time of diagnosis, the mean age was 39.9 years, 66% of the primary sclerosing cholangitis patients were male and 71% had associated inflammatory bowel disease, most commonly chronic ulcerative colitis. Long-term follow-up (mean: 6.0 years; range: 2.7 to 15.5 years) was available in all patients. During follow-up, 59 (34%) of the patients died: 55 in the symptomatic group and four in the asymptomatic group. Median survival from the time of diagnosis of primary sclerosing cholangitis at the Mayo Clinic was 11.9 years. Survival in the asymptomatic group was significantly decreased compared with that in a control population matched for age, race and sex. Multivariate analysis (Cox proportional hazards regression modeling) revealed that age, serum bilirubin concentration, blood hemoglobin concentration, presence or absence of inflammatory bowel disease and histologic stage on liver biopsy were independent predictors of high risk of dying. The development of a multivariate statistical survival model is a major step in identifying individual primary sclerosing cholangitis patients at low, moderate and high risk of dying. Such models will be useful for stratifying patients in therapeutic trials, in patient counseling and in patient selection and timing of liver transplantation.

Adult↗
PubMed1989

The role of exercise-induced silent myocardial ischemia in patients with abnormal left ventricular function. A report from the Coronary Artery Surgery Study (CASS) registry.

To evaluate the significance of ischemic ST depression without anginal chest pain (silent ischemia) during exercise testing among patients with abnormal left ventricular function, the data on 121 such patients with proven coronary artery disease (CAD) from the Coronary Artery Surgery Study (CASS) registry were analyzed. The patients with silent ischemia (group 1) were compared to: 124 CAD patients with both ST depression and angina (symptomatic ischemia, group 2); 159 CAD patients with neither ST depression nor angina (no ischemia, group 3); and 37 patients without CAD (controls). Survival at 7 years with medical therapy was similar for groups 1 (55%) and 2 (60%), but was substantially better for group 3 (73%, p = 0.001). Among group 1 patients with silent ischemia, survival was related to the severity of CAD (p = 0.001). Patients with silent ischemia and three-vessel CAD had a poor 7-year survival rate (37%) when treated medically. A comparable but non-randomized group of patients with silent ischemia and three-vessel CAD who underwent coronary artery bypass surgery had a much better 7-year survival rate (83%, p less than 0.0001). These results suggest that among patients with CAD and abnormal left ventricular function, silent ischemia adversely affects survival and can identify a higher risk subset of patients whose survival might be improved after coronary bypass surgery.

Coronary Disease↗
PubMed1989

Age variation in the association between angiographic coronary disease and angina from the Coronary Artery Surgery Study (CASS)

Between July 1974 and May 1979, 19,153 non-randomized patients without prior cardiac surgery and with chest pain were studied angiographically and enrolled in the Coronary Artery Surgery Study (CASS). The primary question addressed by this paper is: for fixed levels of coronary artery disease, are the presence and severity of angina pectoris greater for older than for younger patients? For those with the same extent of disease, older patients were more likely to have angina and to exhibit more severe symptoms. After adjustment for covariates using logistic regression analysis, age was found to be an important, independent predictor of the presence and severity of angina. There are many possible explanations for these findings, although physiologic factors related to aging, the disease process, and deconditioning associated with an increased sedentary life style seem most reasonable. Another possibility has to do with referral patterns for study and the prevalence of angina in the different age groups.

Adult↗
PubMed1989

Medical and surgical management of early Q wave myocardial infarction. I. Effects of surgical reperfusion on survival, recurrent myocardial infarction, sudden death and functional class at 10 or more years of follow-up.

To define the outcome of patients given medical or surgical therapy for Q wave myocardial infarction, 387 patients were followed up for 10 to 13 years (mean 11.4). On study entry the groups had similar distributions for variables such as mean age, gender, previous myocardial infarction, abnormal creatine kinase activity, area of infarction, number of vessels diseased and clinical classification. The hospital mortality rate of the medical versus surgical group was 11.5% (23 of 200) versus 5.8% (11 of 187) (p = 0.07). Early reperfusion (that is, less than or equal to 6 h) resulted in a lower mortality rate than did medical therapy--2% (2 of 100) versus 11.5% (23 of 200) (p less than 0.05)--whereas the hospital mortality rate with late reperfusion was 10.3% (9 of 87). The long-term mortality rate of the medical and surgical groups was 41% (82 of 200) versus 27% (51 of 187) (p = 0.0007) with use of an adjusted Cox proportional hazards model. In the survivors, the differences between medical and surgical groups in recurrent myocardial infarction, mortality associated with reinfarction and sudden death were prospectively followed and evaluated by the life table method. Recurrent myocardial infarction was not prevented by surgical reperfusion or medical therapy (23% in both groups), however, the mortality rate in patients with recurrent infarction was higher in the medical therapy group--36.6% (15 of 41) versus 17.5% (7 of 40) (p = 0.04). The mortality difference did not depend on early or late surgical reperfusion. In the in-hospital survivors, the incidence of sudden death was 17.5% in the medical (31 of 177) versus 7.4% (13 of 176) in the surgical group (p = 0.01). This difference was much more pronounced in the early reperfusion group. Functional class was significantly lower than that for medical therapy in the early reperfusion but not the late reperfusion group. Thus, in comparable groups given medical and surgical therapy for acute myocardial infarction and followed up for greater than or equal to 10 years, surgical reperfusion appears to offer improved longevity in selected cases (when implemented early) but does not prevent recurrent myocardial infarction. The associated mortality with recurrent myocardial infarction is less as is the incidence of sudden death. Finally, lower functional class occurs most often in patients given early reperfusion.

Acute Disease↗
PubMed1989

Medical and surgical management of early Q wave myocardial infarction. II. Effects on mortality and global and regional left ventricular function at 10 or more years of follow-up.

To determine the long-term effect of surgical reperfusion on survival and left ventricular function of patients with anterior and inferior Q wave myocardial infarction, 387 patients were followed up for greater than or equal to 10 years after early Q wave infarction. In the anterior infarction group, 102 received conventional therapy and 101 underwent surgical reperfusion. The overall hospital mortality rate in the medically and surgically treated patients was different (16.7% [17 of 102] versus 6.9% [7 of 101], p less than 0.05). The cumulative 13 year actuarial mortality rate widened between the anterior medical and surgical groups (54% versus 31%, p = 0.0003) by the adjusted Cox proportional hazards model. The hospital mortality rate with early reperfusion (that is, less than or equal to 6 h of symptom onset) was 2% (1 of 51), whereas the mortality rate with late reperfusion was 12% (6 of 50). The 13 year actuarial cumulative mortality rate was significantly lower in both the early and late reperfusion groups (30% and 33%, respectively) than in the conventional therapy group (54%, p = 0.0006). The mortality rate in patients receiving surgery after surviving initial medical therapy was 50% (15 of 30). In the survivors of anterior Q wave myocardial infarction, improved global ejection fraction was seen in the patients undergoing early (54 +/- 13%) and late (50 +/- 10%) surgery relative to those receiving conventional therapy (43 +/- 11%, p less than 0.05). Only the early reperfusion group had better regional function of the anterior wall than that of the conventional therapy group. Thus, ventricular function correlated with improved long-term survival. In the patients with inferior Q wave myocardial infarction, the overall hospital mortality rate in the medical and surgical groups was not different (6.1% [6 of 98] versus 4.6% [6 of 86], p = NS). Likewise, the 13 year actuarial cumulative mortality rate was not different between the medical and surgical groups overall (32% versus 30%, p = 0.29) by the adjusted Cox proportional hazards model. The hospital mortality rate in the early reperfusion group was lower than that in the late reperfusion group (2.0% [1 of 49] versus 8.1% [3 of 37], p = NS). The 13 year actuarial cumulative mortality rate was lower in the early surgical group compared with that in the medical group (19% versus 32%, p = 0.04). The late surgical group had a similar 13 year actuarial cumulative mortality rate to that of the medical group (47% versus 32%, respectively, p = 0.47).(ABSTRACT TRUNCATED AT 400 WORDS)

Cardiac Catheterization↗
PubMed1989

Research collaboration.

The complexity and cost of cardiovascular medical care dictate research to deliver high quality and cost-conscious cardiovascular care. This goal is aided by modeling medical decision making. To be useful, the modeling must be based on real data so that the results can serve as a guide to actual practice. It is suggested that a registry of randomized clinical trials and larger data bases in cardiovascular disease and health care delivery be established. The registry would be a resource for those desiring to model decision making. The registry would contain key words allowing retrieval by modelers accessing the registry and would contain contact information for consideration of possible collaborative work. The initiation of such a registry should contain plans for its evaluation to determine whether the registry itself is a cost-effective tool to encourage the needed research.

Clinical Trials as Topic↗
PubMed1989

A prospective study of the role of cardiovascular risk factors and fitness in industrial back pain complaints.

The authors conducted a prospective study of risk factors for industrial back pain complaints among 3,020 aircraft manufacturing employees. The study subjects completed a cardiovascular risk questionnaire, and were asked about their smoking status and past medical history, including previous back problems. Premorbid submaximal treadmill testing to predict maximum oxygen uptake (Vo2max) was completed in 2,434 subjects who were not excluded from testing due to cardiovascular risk screening. During several years of subsequent follow-up, 279 subjects reported back problems. Those who reported smoking at the time of the premorbid examination were significantly more likely to report a subsequent back problem than nonsmokers (P = 0.002). When controlling for sex and age, cardiovascular fitness, as measured through VO2max, was not predictive of future back injury reports (P = 0.26).

Adult↗
PubMed1989

Isometric lifting strength as a predictor of industrial back pain reports.

The objective of our investigation was to study isometric lifting strength in a population of industrial workers who perform a great variety of manual tasks, and to determine whether isometric strength is predictive of future back problems in such a population. Of 3,020 study subjects, 2,178 (72%) underwent strength testing in three standard lifting positions. During a 4-year follow-up period, 172 subjects tested reported back problems. When examining each isometric lift separately as a predictor of industrial back pain reports, those with greater isometric strength were at significantly greater risk than were weaker workers. However, after controlling for the effects of age, only a slight trend remained. For the blue collar workers in this study, isometric lifting strength testing was ineffective in identifying individuals at risk for industrial back problems.

Adult↗
PubMed1989

Central ventilatory dysfunction in myelodysplasia: an independent determinant of survival.

Central ventilatory dysfunction (CVD) is a significant complication of myelodysplasia with Arnold-Chiari type II defect. The records of 616 patients with myelodysplasia were reviewed and CVD was documented in 35 cases (5.7 per cent): it was the single most common cause of death in this population. There was no significant association between CVD and level of lesion, severity of hydrocephalus, hemorrhage or infection. The effects of CVD may be variable, with some patients having spontaneous remission and others having severe, often fatal, disruption of ventilation.

Follow-Up Studies↗
PubMed1989

Regimen-related toxicity and early posttransplant survival in patients undergoing marrow transplantation for lymphoma.

Ninety-five patients transplanted for malignant lymphoma were retrospectively evaluated for regimen-related toxicity (RRT) and early posttransplant survival. Nineteen patients developed life-threatening (grade 3) or fatal (grade 4) RRT in one or more organs. Grade 3 or 4 RRT was more common in patients with advanced disease versus those transplanted earlier in their course (P = .008), and was more common in patients with advanced disease conditioned with cytarabine (Ara-C)/total body irradiation (TBI) versus those prepared with cyclophosphamide (CY)/TBI (P = .033). There was no significant difference in the incidence of grade 3 or 4 toxicity in autologous, histocompatibility locus antigen (HLA)-identical, or HLA-mismatched marrow recipients. Grade 3 or 4 RRT tended to be more common and 100-day survival worse in patients with a Karnofsky performance status of less than 90 (P = .063 and .0002, respectively). Patients receiving 20 Gy or more of mediastinal irradiation before coming to transplant had more idiopathic or cytomegalovirus (CMV) interstitial pneumonitis than those who received less than 20 Gy (30% v 9%, P = .027). The probability of survival decreased with the number of organs in which toxicity was observed (P = .0001). Severe or fatal toxicities directly related to the preparative regimen are a significant problem in the treatment of patients with advanced malignant lymphoma and can be reduced by carrying out transplantation earlier in the course of the disease.

Actuarial Analysis↗
PubMed1989

Improved survival of surgically treated patients with triple vessel coronary artery disease and severe angina pectoris. A report from the Coronary Artery Surgery Study (CASS) registry.

We examined survival rates during a 6-year follow-up of patients in the registry of the Coronary Artery Surgery Study who had three vessel coronary artery disease and Canadian Cardiovascular Society class III-IV angina pectoris. All patients had a stenosis of 70% or greater in either the mid or proximal segment of all three coronary arteries. There were 679 medically treated patients and 1921 surgically treated patients in this nonrandomized comparison. Patients were stratified by left ventricular wall motion score and number of proximal coronary artery stenoses; after adjustment for these variables, the estimated probability of being alive at 6 years was 82% for surgically treated patients and 59% for medically treated patients (p less than 0.0001). Among patients with the most severe left ventricular dysfunction (left ventricular wall motion score of 16 to 30), the 6-year survival rate was 63% for surgically treated patients and 30% for medically treated patients (p less than 0.0001). Those with three proximal lesions (all gradations of left ventricular score) had an 81% 6-year survival rate with surgical treatment and 40% with medical treatment (p less than 0.0001). Ninety percent of surgically treated patients with normal ventricular function were living at 6 years and 78% of medically treated patients (p less than 0.0001). Among these patients, the survival rate was significantly better after surgical treatment than after only medical treatment if two or three proximal stenoses were present. If no proximal lesions were present (all categories of left ventricular function), 84% of surgically treated patients and 67% of medically treated patients were alive at 6 years (p less than 0.0001). In a multivariate (Cox) analysis of preoperative clinical, hemodynamic, and angiographic factors, early operation was a strong predictor of survival (estimated relative risk 0.38).

Actuarial Analysis↗
PubMed1989

Strategies for risk evaluation of sudden cardiac incapacitation in men in occupations affecting public safety.

Sudden cardiac incapacitation occurring during critically stressful circumstances in men engaged in a variety of occupations may compromise public safety. Since the primary cause of this incapacitation is usually heart disease, more effective medical screening has been advocated. We report the annual incidence of sudden cardiac incapacitation in four clinical groups--4105 healthy men (Group I), 537 men with atypical chest pain syndromes (Group II), 1374 hypertensive men (Group III), and 2373 men with clinically manifest coronary heart disease (Group IV)--who have been examined and tested by maximal exercise with the Bruce protocol in Seattle community practice. Five strategies for prospective risk assessment are presented in these groups, namely age alone, clinical diagnosis before testing, the combination of both parameters, exercise-enhanced risk assessment, and the exercise criteria proposed by a Task Force for Ischemic Heart Disease (Bethesda Conference XVIII, 1986). We conclude that the exercise-enhanced risk assessment is the most effective of these strategies.

Accident Prevention↗