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Biomedical subjects

E Nelson

Publications and source records attributed to E Nelson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Fibrin sealant reduces the duration and amount of fluid drainage after axillary dissection: a randomized prospective clinical trial.

BACKGROUND: Patients who have axillary dissections during lumpectomy or modified radical mastectomy for breast carcinoma accumulate serosanguinous fluid, potentially resulting in a seroma. Currently accepted practice includes insertion of one or more drains for fluid evacuation. This multicenter, randomized, controlled, phase II study was undertaken to evaluate whether a virally inactivated, investigational fibrin sealant is safe and effective when used as a sealing agent to reduce the duration and volume of serosanguinous fluid drainage and to determine the dose response of this effect. STUDY DESIGN: Patients undergoing lumpectomy or modified radical mastectomy were randomized to treatment with 4, 8, or 16 mL of fibrin sealant or control (no agent) at the axillary dissections site. Patients undergoing modified radical mastectomy also received an additional 4 or 8 mL of fibrin sealant at the skin flap site. Efficacy was evaluated by the number of days required for wound drainage and the volume of fluid drainage compared with control. Safety was confirmed by clinical course, the absence of viral seroconversion, and no major complications attributable to the sealant. RESULTS: The 4-mL axillary dissection dose of fibrin sealant significantly reduced the duration and quantity of fluid drainage from the axilla following lumpectomy (p < or = 0.05). In the modified radical mastectomy patients, a 16-mL axillary dissection dose combined with an 8-mL skin flap dose was significantly effective in reducing the number of days to drain removal (p < or = 0.05) and fluid drainage (p < or = 0.01). There were no fibrin sealant patient viral seroconversions and no major complications attributable to the sealant. A number of wound infections were noted, although this may represent a center-specific effect. CONCLUSIONS: Application of fibrin sealant following axillary dissection at the time of lumpectomy or modified radical mastectomy can significantly decrease the duration and quantity of serosanguinous drainage. The viral safety of the product was also supported.

Axilla↗
PubMed2001

Protein docking using continuum electrostatics and geometric fit.

The computer program DOT quickly finds low-energy docked structures for two proteins by performing a systematic search over six degrees of freedom. A novel feature of DOT is its energy function, which is the sum of both a Poisson-Boltzmann electrostatic energy and a van der Waals energy, each represented as a grid-based correlation function. DOT evaluates the energy of interaction for many orientations of the moving molecule and maintains separate lists scored by either the electrostatic energy, the van der Waals energy or the composite sum of both. The free energy is obtained by summing the Boltzmann factor over all rotations at each grid point. Three important findings are presented. First, for a wide variety of protein-protein interactions, the composite-energy function is shown to produce larger clusters of correct answers than found by scoring with either van der Waals energy (geometric fit) or electrostatic energy alone. Second, free-energy clusters are demonstrated to be indicators of binding sites. Third, the contributions of electrostatic and attractive van der Waals energies to the total energy term appropriately reflect the nature of the various types of protein-protein interactions studied.

Computer Simulation↗
PubMed2001

The miseries of passive smoking.

Passive smoking is defined as an involuntary exposure to a combined but diluted cigarette sidestream smoke (SS, gas and particle phases that are evolved from the smoldering end of a cigarette while the smoker is not puffing) and the exhaled smoke from smokers. SS contains numerous cytotoxic substances such as polycyclic aromatic hydrocarbons (PAHs), aromatic amines, nitrosamines, heavy metals, poisonous gases, pesticide residues, and radioactive elements in quantities much higher than those found from the cigarette mainstream smoke (MS) which is puffed by smokers. Passive smoking is found to be the cause of death from cancers and cardiac disease. Furthermore, it damagingly involves reproductive organs, the nervous system, genetic materials, and is particularly hazardous to mother and child during pregnancy and to those with a history of asthma, chronic infections, induced or earned immune deficiency, or predisposed susceptibility.

Abnormalities, Drug-Induced↗
PubMed2001

An integrative approach for studying the etiology of alcoholism and other addictions.

Studies of alcoholism etiology often focus on genetic or psychosocial approaches, but not both. Greater understanding of the etiology of alcohol, tobacco and other addictions will come from integration of these research traditions. A research approach is outlined to test three models for the etiology of addictions--behavioral undercontrol, pharmacologic vulnerability, negative affect regulation--addressing key questions including (i) mediators of genetic effects, (ii) genotype-environment correlation effects, (iii) genotype x environment interaction effects, (iv) the developmental unfolding of genetic and environmental effects, (v) subtyping including identification of distinct trajectories of substance involvement, (vi) identification of individual genes that contribute to risk, and (vii) the consequences of excessive use. By using coordinated research designs, including prospective assessment of adolescent twins and their siblings and parents; of adult substance dependent and control twins and their MZ and DZ cotwins, the spouses of these pairs, and their adolescent offspring; and of regular families; by selecting for gene-mapping approaches sibships screened for extreme concordance or discordance on quantitative indices of substance use; and by using experimental (drug challenge) as well as survey approaches, a number of key questions concerning addiction etiology can be addressed. We discuss complementary strengths and weaknesses of different sampling strategies, as well as methods to implement such an integrated approach illustrated for the study of alcoholism etiology. A coordinated program of twin and family studies will allow a comprehensive dissection of the interplay of genetic and environmental risk-factors in the etiology of alcoholism and other addictions.

Alcoholism↗
PubMed2001

Same patients, same critical events--different systems of care, different outcomes: description of a human factors approach aimed at improving the efficacy and safety of sedation/analgesia care.

The practice of sedating pediatric patients undergoing diagnostic and therapeutic procedures represents an ideal model for evaluating systems of health care delivery. We present detailed evidence of how different systems acting on the same patient under similar conditions result in very different outcomes. In contrast to epidemiological methods, our research follows a Human Factors approach of observing a small number of representative cases in great detail to characterize the critical components and processes of ideal sedation care. In this descriptive article we present a framework by which this work domain can be codified and evaluated. We conclude with a demonstration of how a patient simulator can be used to quantify responses to sedation emergencies. These data constitute the basis for innovating novel sedation care systems and strategies that will optimize safety and efficacy.

Analgesics↗
PubMed2000

A randomized, controlled, phase II trial comparing escalating doses of subcutaneous interleukin-2 plus antiretrovirals versus antiretrovirals alone in human immunodeficiency virus-infected patients with CD4+ cell counts >/=350/mm3.

A total of 73 patients with baseline CD4+ cell counts >/=350 cells/mm3 who were receiving combination antiretroviral therapy (ART) were randomized to receive subcutaneous interleukin-2 (IL-2; n=36) in addition to ART or to continue ART alone (n=37). Subcutaneous IL-2 was delivered at 1 of 3 doses (1.5 million international units ¿MIU, 4.5 MIU, and 7.5 MIU per dose) by twice-daily injection for 5 consecutive days every 8 weeks. After 24 weeks, the time-weighted mean change from baseline CD4+ cell count was 210 cells/mm3 for recipients of subcutaneous IL-2, compared with 29 cells/mm3 for recipients of ART alone (P<.001). There were no significant differences between treatment groups for measures of plasma human immunodeficiency virus RNA (P=.851). Subcutaneous IL-2 delivered at doses of 4.5 MIU and 7.5 MIU resulted in significant increases in CD4+ cell count (P=.006 and P<.001, respectively), compared with that seen in control patients. These changes were not significant in the 1.5 MIU dose group compared with that in the control patients (P=.105). Side effects that occurred from subcutaneous IL-2 administration were generally low grade, of short duration, and readily managed in an outpatient environment.

Adult↗
PubMed2000

Diclofenac treatment prolongs renal transit time in acute ureteral obstruction: a renographic study.

OBJECTIVE: Prostaglandin inhibitors, mostly diclofenac, are currently first-choice therapy for ureteral colic, their main action being reduction of intrapelvic pressure and diuresis. We hypothesized that diclofenac, by increasing tubular reabsorption, can delay excretion of contrast medium and give a false impression of severe obstruction. METHODS: Gamma camera renography was performed with 50 MBq (99)Tc(m)-MAG3 before and with 150 MBq 30 min after intramuscular injection of 75 mg diclofenac in 10 patients with acute ureteral colic. The time to maximum isotope activity in each kidney, T(max), was compared with T(max) in 10 control patients, who did not receive diclofenac but underwent two identical renographies. RESULTS: T(max) was significantly delayed after diclofenac, from 353 s at baseline to >1,200 s on the stone side, and from 225 to 465 s on the healthy side. Without diclofenac there was no T(max) retardation between the two renographies. CONCLUSION: Diclofenac treatment can lead to overestimation in ureteral stone disease, by delaying renal excretion bilaterally, but predominantly on the side of calculus.

Acute Disease↗
PubMed2000

Exposure to suggestion and creation of false auditory memories.

The experiment investigated the possibility of creating false auditory memory through exposure to suggestion. Research by Loftus and others has indicated that, through suggestion, false memories can be created. Participants viewed a short film and were given a 9-item questionnaire. Eight questions were used as filler while one question asked respondents to recall a phrase one character had said. Although the character actually said nothing, 23 of 30 respondents recalled having heard him speak and specifically recalled his words. This statistically significant result shows that auditory memories can also be created.

Adolescent↗
PubMed2000

Computer use and needs of internists: a survey of members of the American College of Physicians-American Society of Internal Medicine.

The American College of Physicians-American Society of Internal Medicine conducted a membership survey in late 1998 to assess their activities, needs, and attitudes. A total of 9,466 members (20.9% response rate) reported on 198 items related to computer use and needs of internists. Eighty-two percent of the respondents reported that they use computers for personal or professional reasons. Physicians younger than 50 years old who had full- or part-time academic affiliation reported using computers more frequently for medical applications. About two thirds of respondents who had access to computers connected to the Internet at least weekly, with most using the Internet from home for e-mail and nonmedical uses. Physicians expressed concerns about Internet security, confidentiality, and accuracy, and the lack of time to browse the Internet. In practice settings, internists used computers for administrative and financial functions. Less than 19% of respondents had partial or complete electronic clinical functions in their offices. Less than 7% of respondents exchanged e-mail with their patients on a weekly or daily basis. Also, less than 15% of respondents used computers for continuing medical education (CME). Respondents reported they wanted to increase their general computer skills and enhance their knowledge of computer-based information sources for patient care, electronic medical record systems, computer-based CME, and telemedicine While most respondents used computers and connected to the Internet, few physicians utilized computers for clinical management. Medical organizations face the challenge of increasing physician use of clinical systems and electronic CME.

Attitude to Computers↗
PubMed1999

The impact of the geometry of the lithotriptor aperture on fragmentation effect at extracorporeal shock wave lithotripsy treatment.

The aim of this study was to determine the impact of the aperture size of an electro-hydraulic lithotriptor on the fragmentation effect. We also wanted to investigate whether a potential change in the capacitance of the pulse forming network (PFN), at a certain energy level, might have an impact on fragmentation rate. Two different apertures with a diameter of 23 and 17 cm respectively were compared using two different values of total PFN capacitance: 50 nF and 80 nF. Model stones of similar size and weight were fragmented. The number of shots for complete fragmentation or the grade of fragmentation after a certain number of shots was measured. This study shows that for the shock wave system used, the 23-cm aperture seems to provide more effective fragmentation as function of the number of shots compared with the 17-cm aperture at the same energy level. Furthermore, a minor change in the PFN capacitance between reasonable limits does not affect the fragmentation efficiency. This article also highlights the fact that it is not relevant simply to compare the voltage level given in the shots in extracorporeal shock wave lithotripsy treatment between different lithotriptors.

Electric Conductivity↗
PubMed1999

Maternal passive smoking during pregnancy and fetal developmental toxicity. Part 1: gross morphological effects.

1. Prenatal exposure of human fetus to tobacco smoke through maternal passive smoking has been epidemiologically linked to reduced birth weight, enhanced susceptibility to respiratory diseases and changes in immune system. However, no data exists indicating teratogenicity of involuntary smoking. Since sidestream smoke of cigarettes makes the most constituent of whole smoke inhaled by nonsmokers, we performed experiments to determine whether passive inhalation of sidestream smoke by rats causes malformations in newborns. 2. Pregnant 230 - 300 g Wistar rats were each placed in a 150 dm3 glass chamber with two holes, each 3 cm in diameter in two opposite walls to provide unforced exchange of fresh air. A third hole was connected to an automatic smoking machine. The head of a commercial filter blond cigarette (13 mg Tar, 0.9 mg Nicotine) was introduced to the chamber through this later hole. Cigarettes were smoked by smoking machine at the rate and volume resembling human smoking and the mainstream smoke was separately collected and discarded. Each rat thus received the sidestream smoke self-diluted in the chamber air. Experiments were performed with either 1, 2, 3 or 4 cigarettes/day during either first, second or third week of a total 21-day pregnancy period. The interval between smoking of cigarettes was 2 h. 3. COHb in blood of negative controls was about 1.2% and after exposure to 1 or 4 cigarettes were 6% and 12.2%, respectively. A dose-dependent reduction of birth weight was observed in newborns (P<0.001); bitemporal diameters and body lengths were reduced accordingly. No macroscopically visible gross anomaly could be observed. After removing the fat tissue and staining the skeleton with alizarin, a widespread ossification retardation could be observed in all exposed groups regardless of the dose. Such a retardation was not limited to a particular bone. 4. These results support epidemiologic data on developmental toxicity of passive smoking and further provide evidence on an unfavorable osteopathic effect of sidestream exposure of mother on fetal development.

Animals↗
PubMed1999

Maternal passive smoking during pregnancy and foetal developmental toxicity. Part 2: histological changes.

1. Evidence has been accumulating on the growth suppressing effects of maternal passive smoking on foetus. Reviewing all literature released during the last two decades and screening for all possible variables such as previous smoking history, maternal age and weight gain, parity and length of gestation, placental weight, and diet, we found no reason to doubt the role of passive smoking during pregnancy in the induction of growth retardation. However, no literature indicates whether these birthweight deficits might hint at other possible hidden abnormalities in tissues. To verify this question, we performed an experiment on rats. 2. We have already reported that pups born to rats with previous exposure to cigarette's sidestream smoke during pregnancy showed a significant and dose-dependent growth retardation. Those pregnant rats were exposed each in a 150 dm3 glass chamber to diluted sidestream smoke of either 1, 2, 3 or 4 commercial blond filter brand cigarettes during either first, second or third week of pregnancy. We have selected a part of each group of pups at random and examined for possible histological changes of lung, liver, stomach, kidney and intestinal tissues. 3. Compared to controls, lung tissues of newborns of smoke exposed mothers showed an enhanced incidence of apoptosis, mesenchymal changes, and hyperplasia of bronchial muscles. Pronounced abnormal changes in haematopoiesis and proliferation of bile duct cells were the most variations from norm observed in liver tissues of exposed pups. Immature glomeruli of kidney, epithelhypoplasia of stomach, and hypoplasia of intestinal villi were common among newborns of exposed mothers than among controls. 4. These results indicate that passive smoking upon pregnancy causes abnormal morphological changes in internal tissues of newborns. At present, we can draw no conclusion as to whether these histological changes will result in functional malformations or possibly late effects, although they should be expected.

Animals↗
PubMed1998

Model sclerotization studies. 4. Generation of N-acetylmethionyl catechol adducts during tyrosinase-catalyzed oxidation of catechols in the presence of N-acetylmethionine.

Incubation of catechol with mushroom tyrosinase in the presence of N-acetylmethionine resulted in the generation of an adduct. This product was identified to be N-acetylmethionyl catechol, on the basis of spectral characteristics and well-characterized chemical reaction of o-benzoquinone with N-acetylmethionine. Enzyme-catalyzed oxidation of catechol and the subsequent nonenzymatic addition of the resultant quinone to N-acetylmethionine accounted for the observed reaction. That the reaction is not confined to catechol alone, but is of general occurrence, can be demonstrated by the facile generation of similar adducts in incubation mixtures containing N-acetylmethionine, tyrosinase, and different N-acetylmethionines, such as 4-methylcatechol and N-acetyldopamine. Attempts to duplicate the reaction with insect cuticular phenoloxidases were not successful, as the excess N-acetylmethionine used in the reaction inhibited their activity. Nevertheless, occurrence of this nonenzymatic reactivity. Nevertheless, occurrence of this nonenzymatic reaction between N-acetylmethionine and mushroom tyrosinase-generated quinones indicates that a similar reaction between enzymatically generated quinones in the cuticle with protein-bound methionine moiety is likely to occur during in vivo quinone tanning as well.

Animals↗
PubMed1998

Efficacy and safety of tolterodine in patients with detrusor instability: a dose-ranging study.

OBJECTIVE: To investigate the efficacy and safety of tolterodine, a new antimuscarinic agent, and define the optimum dosage in patients with symptoms of detrusor instability (urgency, increased frequency of micturition and/or urge incontinence). PATIENTS AND METHODS: A double-blind, placebo-controlled, multicentre study was carried out; after a 1-week run-in period to establish baseline values, 81 patients were randomized to receive placebo or tolterodine 0.5, 1, 2 or 4 mg twice daily for 2 weeks. Micturition (diary) variables, urodynamics and subjective urinary symptoms were assessed after 2 weeks' treatment. RESULTS: A per-protocol analysis of efficacy in 64 patients showed dose-related improvements in recorded micturition and urodynamic variables, e.g. at a dosage of 2 mg twice daily, the frequency of micturition, episodes of incontinence and pad use were reduced by 20%, 46% and 29%, respectively, while the volume at first contraction increased by 89 mL. The 4 mg dosage was associated with a large increase in residual urinary volume and an increased incidence of dry mouth. The incidence of adverse events (mainly mild or moderate antimuscarinic effects) was comparable with placebo at tolterodine dosages of < or = 2 mg. No serious adverse events were observed and tolterodine had no clinically significant impact on electrocardiographic or laboratory findings. CONCLUSION: The results indicate that tolterodine offers an effective treatment for the symptoms of detrusor instability. The optimum dosage appears to be 1-2 mg twice daily.

Adult↗
PubMed1998

Looking at care from the inside out: a conceptual approach to geriatric care.

Today, managing care from the "outside in" is the predominant model for changing health care. The risk of this outside-in approach is that the health care system may lose sight of the people and communities for which it serves and cares. In this article, an "inside-out" model for viewing health care in a geriatric population is presented from the perspective of patients and providers, placing the provider in a proactive rather than reactive role. By focusing attention on the outcomes or value a patient is experiencing, providers are challenged to consider new ways of managing care.

Aged↗