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E Hoffman

Publications and source records attributed to E Hoffman.

At least 37 records · Page 2Linked to original sources
PubMed1998

An Experimental Investigation of the Incentives to Form Agricultural Marketing Pools.

This paper presents theoretical extensions and laboratory tests of Hoffman and Libecap's (1994) model of individual firms' incentives to form agricultural marketing pools. The key incentives are lower variance in output prices and economies in scale in marketing. This paper extends the model by formulating the pooling problem as a game of incomplete information in which firms have heterogeneous and private risk attitudes. An experiment is conducted to test the theoretical implications of this model. Statistical analysis of the experimental data supports the model predictions of pooling rates, but also reveals that subjects form systematic probability biases and do not behave as strategically as the model suggests. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Development of a quantitative vancomycin immunoassay for the Abbott AxSYM analyzer.

A novel fluorescence polarization immunoassay for vancomycin on Abbott AxSYM analyzer is described. The immunoassay allows for the accurate quantification of vancomycin in the presence of the crystalline degradation product (CDP). It displays dilution linearity from 1.0 microg/ml to 100.0 microg/ml, coefficients of variation ranging from 2.94% to 4.26%, recovery from 98% to 105%, and a sensitivity of <2.0 microg/ml. The assay demonstrates no cross-reactivity to crystalline degradation product, and to commonly-prescribed and over-the-counter drugs, as well as a minimum interference from endogenous substances.

Animals↗
PubMed1997

Bioavailability of lead to juvenile swine dosed with soil from the Smuggler Mountain NPL Site of Aspen, Colorado.

Bioavailability of lead (Pb) has become an issue in quantifying exposure of sensitive populations and, where necessary, establishing cleanup levels for contaminated soil. Immature swine were used as a model for young children to estimate the degree to which Pb from two fully characterized composite samples from the Smuggler Mountain Superfund Site in Aspen, Colorado may be bioavailable to resident children. The composite soils contained 14,200 and 3870 micrograms Pb/g of soil. Relative and absolute enteric bioavailabilities of Pb in soil (oral dose groups of 75,225, and 675 micrograms Pb/kg body wt/day) were estimated by comparison with an orally administered soluble Pb salt (lead acetate = PbAc2.3H2O) (dose groups of 0, 75, and 225 micrograms Pb/kg body wt/day) and an intravenously administered aqueous solution of Pb (100 micrograms Pb/kg/ day) from the same trihydrate salt administered daily for 15 days to 50 juvenile swine. The biological responses (area under the blood Pb concentration-time curve, and the terminal liver-, kidney-, and bone-lead concentrations) produced by Pb from PbAc2.3H2O and lead-contaminated soils were determined. This study revealed Pb from soil containing 14,200 micrograms Pb/g of soil had a bioavailability relative to Pb from PbAc (RBA), ranging from 56% based on the area under the blood lead concentration-time curve (AUC) versus dose, to 86% based on calculations from liver-Pb loading versus dose. Similarly, Pb from soil containing 3870 micrograms Pb/g of soil had an RBA ranging from 58% based on the AUC versus dose, to 74% based on calculations from liver- and kidney-Pb loading versus dose. Bioavailability of Pb in soils may be more or less than EPA's default RBA of 60%, therefore, measuring site-specific RBAs provides a basis for improved exposure and risk assessment.

Animals↗
PubMed1997

Effects of hydroxyurea administration on the body weight, body composition and exercise performance of patients with sickle-cell anaemia.

1. As an ancillary study carried out during the recently completed Multicenter Study of Hydroxyurea, we examined the effect of hydroxyurea on the body weight, body composition and exercise capacity of adult patients with sickle-cell anaemia. 2. The subjects received either hydroxyurea (six males and four females) or placebo (eight males and six females). Data for each subject were generated during four separate 24 h admissions to the General Clinical Research Center. These admissions occurred at baseline and then at 6, 12 and 18 months after the start of study drug (hydroxyurea or placebo) administration. During each admission, body composition was measured by using a dual X-ray absorptiometer, and exercise testing was performed by cycle ergometry. Anaerobic performance was assessed according to a 'Wingate' protocol (20 s at maximal intensity against a cycling resistance of 7.5% body weight). Aerobic performance was examined using a steady state submaximal exercise protocol (10 min cycling time). 3. At baseline, no significant difference in any parameter was found between the hydroxyurea- and placebo-treated groups. At 18 months, the hydroxyurea-treated subjects exhibited an average weight gain of 3.16 kg. The mean weight gain in the placebo-treated subjects was 1.82 kg. Body composition analysis showed that the additional weight in both groups involved both lean and fat body mass components. In anaerobic performance, the subjects given hydroxyurea showed an increase in peak muscle power of 104.9 W. The placebo group also showed an increase, but theirs was a more modest gain of 57.7 W. The most marked improvement in anaerobic performance was observed in the hydroxyurea-treated men (P < 0.05). In aerobic performance, the hydroxyurea-treated subjects exhibited a decrease in peak heart rate response to a standardized workload of 15.2 beats/min, as compared with a decrease of only 4.3 beats/min in the placebo-treated patients. 4. Taken together, the overall weight gain, combined with increases in both anaerobic muscular performance and aerobic cardiovascular efficiency, provides objective data to support the subjective impression that hydroxyurea administration produces an improvement in the physical capacity of patients with sickle-cell anaemia.

Adult↗
PubMed1997

Management of patients with life-threatening ventricular tachyarrhythmias in the defibrillator era: the need to differentiate.

Patients with a history of sustained ventricular tachyarrhythmias form an extremely inhomogeneous group with respect to presenting arrhythmia, underlying cardiac disease, and therefore, risk of dying suddenly. For subgroups such as ventricular tachycardia in the absence of underlying cardiac disease, radiofrequency catheter ablation offers cure. In others, implantation of a cardioverter defibrillator already appears to have gained the therapy of first choice, leaving only a secondary role to antiarrhythmic drugs. It must be emphasized however, that these new therapeutic strategies have their pros and cons like the older, seemingly out-fashioned approaches of noninvasively or invasively guided antiarrhythmic drug therapy or empiric amiodarone treatment. Until the advent of controlled randomized trials comparing the implantable cardioverter defibrillator (ICD) with the best other, usually medical form of treatment, physicians must continue to base their individual therapeutic decisions on circumstantial published and personal experience. In doing so, the recent achievements of catheter ablation and defibrillator implantation have definitely improved patient care, but have not made antiarrhythmic drugs jobless. With all the alternatives at hand, it remains a challenging task to weigh the benefits and risks of the various approaches against each other in an attempt to tailor the antiarrhythmic intervention to the very individual need of the patient.

Amiodarone↗
PubMed1996

Case reports: cocaine-associated accelerated hypertension and renal failure.

These are two cases of cocaine abuse with the following previously unreported cocaine-associated features: 1) biopsy-proven accelerated/malignant hypertension, 2) association of cocaine with persistent hypertension, and 3) renal failure with rapid progression to end-stage renal disease that did not reverse following blood pressure control.

Adult↗
PubMed1996

Ocular copper deposition associated with benign monoclonal gammopathy and hypercupremia.

The deposition of copper on Descemet's membrane and the anterior and posterior lens capsule with extreme hypercupremia and IgG hypergammaglobulinemia has been previously described with multiple myeloma and pulmonary carcinoma. A 66-year-old man presenting with blurred vision was found to have bilateral golden-brown metallic dust-like deposits on the central region of Descemet's membrane and the anterior and posterior lens capsule. Laboratory investigations revealed an elevated serum copper level 10 times the normal level associated with a monoclonal gammopathy and a normal ceruloplasmin level. Copper binding to the serum proteins was investigated by three biochemical methods. The results demonstrated that the major copper binding fraction in the serum was IgG. N-terminal amino acid analysis of the IgG did not find the sequence of Asp-Ala-His, which has been shown to be a copper binding site in albumin. This is the first report of benign monoclonal gammopathy being associated with the ocular deposition of copper.

Aged↗
PubMed1995

Environment-driven responses in progressive supranuclear palsy.

The neurological signs and behaviors that accompany degenerative diseases associated with fronto-striatal dysfunction are incompletely described. We observed several novel environmentally-driven behaviors in seven patients with progressive supranuclear palsy (PSP). All patients had cognitive deficits with greatest impairments on tests of frontal lobe function, and frontal lobe cerebral perfusion was significantly reduced in 4 of the 5 who had single photon emission computed tomography (SPECT) brain scans. Visual grasping, in which a patient's gaze was attracted to an incidental object in the environment such as a TV set or mirror, was preeminent. Once fixed, there was inability to release the gaze and shift to another object. In other instances, removing a table placed in front of a patient or unbuckling of his seat belt would make him stand up, which was impossible on command. Similarly, playing music would induce rhythmic foot beating, which was never obtained on command. There were compulsive utilization behaviors, such as repetitively picking up and replacing the telephone for no apparent reason. As expected, there were signs of heightened facial reflexes, grasp reflexes, apraxia of eyelid opening, echolalia and echopraxia. We postulate that these stimuli-oriented behaviors stem from parietal lobe disinhibition due to fronto-striatal dysfunction.

Aged↗
PubMed1995

Physician assistants and nurse practitioners in Louisiana.

In recent years there has been tremendous growth in the medically related professions of Louisiana. Two such groups are physician assistants and nurse practitioners. The following article presents an overview of the development of these two fields and their geographic distribution in the state relative to Health Professional Shortage Areas.

Humans↗
PubMed1995

Iowa's National Laboratory for the study of Rural Telemedicine: a description of a work in progress.

As the federal administration advances the idea of the "information superhighway," many disciplines are being challenged to find ways to use advanced telecommunications to improve access to information, enhance learning opportunities, and achieve higher levels of international competitiveness. Telemedicine, the use of communications technology in the practice of medicine, may change the way rural health care is provided by improving access to medical information, diagnostic tools, and consultations. The information and health care services required by health care professionals are rapidly changing, and dissemination of this information to isolated practitioners has proven to be difficult. By providing support electronically from a central site, the most current information is more readily available. Using test-bed hospitals in rural and urban settings, the National Library of Medicine-funded National Laboratory for the Study of Rural Telemedicine at the University of Iowa is currently developing the necessary infrastructure to support targeted projects studying how telemedicine applications can be made more effective and readily available.

Clinical Laboratory Information Systems↗
PubMed1995

Systemic sclerosis sine scleroderma: an unusual presentation in scleroderma renal crisis.

Renal involvement in systemic sclerosis (SSc) has a negative influence on prognosis. Cases of SSc sine scleroderma have been reported in which organ failure occurred but was not accompanied by cutaneous damage, which in some instances did develop later. We describe a patient who, after 6 months of symmetric polyarthritis, developed rapid progressive renal failure without skin changes. A diagnosis of scleroderma renal crisis, confirmed histologically, was made. Anti-RNAP III antibodies were positive. The patient developed typical scleroderma skin changes after renal failure. Despite treatment, SSc advanced to fatal endstage renal disease.

Antibodies↗
PubMed1995

Allied health professional manpower in Louisiana.

In recent decades there has been a virtual transformation of medicine. A host of factors including technological change and increasing governmental intrusion and requirements as well as complex changes in the private sector have made the practice of medicine dramatically different than in the past. A concomitant change has been the virtual explosion in the number, complexity, and legal status of what are commonly termed the allied health professions. The following article was designed to present a historical overview of 10 of the most common such occupations and to discuss their unique training and employment status in the state. Implications for the future of medicine in the state are discussed.

Allied Health Personnel↗
PubMed1994

The in-vivo effects of an intramedullary implant evoking a constant radial stress to bone. An animal study in the tibia of the goat.

Initial stability is essential for successful bone ingrowth into non-cemented prostheses. An entire new concept to increase the initial stability directly after implantation of intramedullary stems was developed (the tension rod prosthesis). The concept is based on a tension rod made out of memory metal that pulls a proximal stem of a prosthesis towards a distal anchor with a constant force. The stress generated along the long axis of the bone produces a radial stress around the prosthesis in the proximal femur. The main goal of this design is to increase the primary stability of the prosthesis during the ingrowth phase and to prevent stress shielding and bone resorption, as realized by the radial force applied to the proximal endosteum of the bone. To assess the efficacy of this concept and to collect data for the anchor design, an implant was developed for implantation into the tibia of the goat. Analyses of push-out strength and bone reactions were performed postoperatively. After 48 weeks the push-out strength of this implant was increased and the histological evaluation showed almost complete osseousintegration. Histomorphometrical analysis showed pronounced, permanent periosteal reactions, located around the anchor of the implant, which generates the radial stress. These first results showed that the bone can withstand the radial stress provoked by the anchor of the tension rod. It is concluded that the concept of a tension rod prosthesis is viable.

Animals↗
PubMed1994

Intramural myocardial shortening in hypertensive left ventricular hypertrophy with normal pump function.

BACKGROUND: In hypertensive left ventricular hypertrophy (LVH), intrinsic myocardial systolic function may be normal or depressed. Magnetic resonance tagging can depict intramural myocardial shortening in vivo. METHODS AND RESULTS: Tagged left ventricular magnetic resonance images were obtained in 30 hypertensive subjects with LVH (mean LV mass index, 142 +/- 41 g/m) and normal ejection fraction (mean, 64 +/- 9%) using spatial modulation of magnetization. In 26 subjects, circumferential myocardial shortening (%S) was compared with results obtained in 10 normal subjects at endocardium, midwall, and epicardium on up to 4 short-axis slices each. Similarly, in 10 subjects, midwall long-axis shortening at basal, midventricular, and apical sites was compared with results obtained in 12 normal volunteers. Circumferential %S was reduced in hypertensive subjects. Mean shortening was 29 +/- 6% at the endocardium in hypertensive subjects versus 44 +/- 6% in normal subjects (P = .0001); 20 +/- 6% at the midwall versus 30 +/- 6% (P = .0001); and 13 +/- 5% at the epicardium versus 21 +/- 5% (P = .0002). However, the transmural gradient in percent shortening from endocardium to epicardium in hypertensive subjects paralleled that in normal subjects. The normal base-to-apex gradient in circumferential %S was absent in LVH. In contrast to normal subjects, circumferential %S showed regional heterogeneity in hypertensive subjects, being maximal in the lateral wall and least in the inferior wall. Longitudinal shortening was also uniformly depressed in hypertensive subjects: 10 +/- 9% at the base versus 21 +/- 6% in normal subjects (P = .0001); 14 +/- 8% at the midventricle versus 18 +/- 3% (P = .03); and 14 +/- 8% at the apex versus 18 +/- 4% (P = .04). CONCLUSIONS: In hypertensive LVH with normal pump function, intramural circumferential and longitudinal myocardial shortening are depressed.

Female↗
PubMed1994

Gene complementation using myoblast transfer into fetal muscle.

Gene complementation by myoblast transfer into neonatal or adult muscle has been proposed as a therapy for primary myopathies as well as to augment non-muscle gene products that may be diminished in the adult circulation. This paper describes a technique whereby myoblasts have been injected into limb muscles of normal and dystrophin-deficient (mdx) fetal mice (during the period of active myotube formation and prior to the development of the host's immune competence) without significantly interfering with fetal viability or further maturation. More mosaic myofibers (myofibers containing both host- and donor-derived myonuclei) appear to result from these transfers than have been reported following myoblast transfer into neonatal muscle or adult muscle. The small size of the fetal hosts' muscles and the lack of well-defined connective tissue septa facilitate migration of donor myoblasts into muscle groups distal to the injection site. The use of donor myoblasts derived from a tetraploid variant of a mouse myogenic cell line (MM14) provides a convenient and permanent cytological marker for the recognition of donor myoblasts and donor-derived myonuclei. When MM14 myoblasts are injected into mdx fetuses, whose muscles lack dystrophin, mosaic myofibers contain sufficient dystrophin to be visualized with routine immunohistochemical techniques. The myoblast transfer system, using fetal hosts, described in this study will facilitate the evaluation of myoblasts as vectors to overcome genetic deficiencies that may be manifested during fetal development.

Animals↗