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At least 793 records · Page 44Linked to original sources
PubMedDate not supplied

Migration from plasticized films into foods. 3. Migration of phthalate, sebacate, citrate and phosphate esters from films used for retail food packaging.

A UK survey of plasticizer levels in retail foods (73 samples) wrapped in plasticized films or materials with plasticized coatings has been carried out. A wide range of different food-types packaged in vinylidene chloride copolymers (PVDC), nitrocellulose-coated regenerated cellulose film (RCF) and cellulose acetate were purchased from retail and 'take-away' outlets. Plasticizers found in these films were dibutyl sebacate (DBS) and acetyl tributyl citrate (ATBC) in PVDC, dibutyl phthalate (DBP), dicyclohexyl phthalate (DCHP), butylbenzyl phthalate (BBP), and diphenyl 2-ethylhexyl phosphate (DPOP) in RCF coatings, and diethyl phthlate (DEP) in cellulose acetate. Foodstuffs analysed included cheese, pate, chocolate and confectionery products, meat pies, cake, quiches and sandwiches. Analysis was by stable isotope dilution GC/MS for DBP, DCHP and DEP, GC/MS (selected ion monitoring) for BBP and DPOP, and GC with flame ionization detection for DBS and ATBC, but with mass spectrometric confirmation. Levels of plasticizers found in foods were in the following ranges: ATBC in cheese, 2-8 mg/kg; DBS in processed cheese and cooked meats, 76-137 mg/kg; 76-137 mg/kg; DBP, DCHP, BBP, and DPOP found individually or in combination in confectionery, meat pies, cake and sandwiches, total levels from 0.5 to 53 mg/kg; and DEP in quiches, 2-4 mg/kg.

Chromatography, Gas↗
PubMedDate not supplied

The occurrence of phthalate ester and di-2-ethylhexyl adipate plasticizers in Canadian packaging and food sampled in 1985-1989: a survey.

Selected foods (260 samples) packaged in materials with the potential to contribute plasticizers to the food, and available food composites (98 samples) obtained from the Canadian Health Protection Branch Total Diet Program, were analysed for phthalate plasticizers and di-2-ethylhexyl adipate (DEHA). The available contacting packaging was also analysed for plasticizers. The results show DEHA in food-contacting film and as a migrant in store-wrapped meat, poultry, fish, cheese and ready-to-eat foods at levels as high as 310 micrograms/g (cheese). DEHA levels in unheated film-wrapped ready-to-eat foods were increased by heating. The di-2-ethylhexyl, dibutyl, butylbenzyl and diethyl phthalate esters (DEHP, DBP, BBP and DEP, respectively) were also found in both the packaging and the contacted foods. Low levels of DEHP (0.065 micrograms/g, average in beverages and 0.29 micrograms/g, average in foods) associated with the use of DEHP-plasticized cap or lid seals, were found in a variety of glass-packaged foods; DBP, BBP and DEHP were found, as previously described, in butter and margarine as migrants from the aluminium foil-paper laminates; and DEP in pies at 1.8 micrograms/g (average) as a migrant from the pie carton windows. In most cases, plasticizers detected in the food were also found in the associated packaging. When possible, 'core' or non-contacting food portions were analysed to verify the migration phenomena.

Adipates↗
PubMed2003

Traumatic brain injury and its effects on synaptic plasticity.

Animal models have been used to simulate the effects of human head trauma. Some of these models have been further utilized to explore how trauma affects specific mechanisms of synaptic plasticity, a cellular model for memory consolidation. Unfortunately, these studies have been more limited in number in spite of their importance for understanding alterations in synaptic plasticity and memory impairments in trauma patients. Research in this area includes well characterized trauma models, genetically engineered animals and neuroprotective studies. One largely ignored but important idea that is entertained here is that trauma may be a crucial aetiological factor for the loss of potassium homeostasis. Moreover, high extracellular potassium has been shown to promote abnormal expression of hippocampal synaptic plasticity due to K(+)-induced glutamate release, thus showing important relationships among trauma, glia, potassium and synaptic plasticity. Collectively, this mini review surveys investigations of head trauma involving altered mechanisms of synaptic plasticity and how trauma may be related to increased risk for dementia.

Alzheimer Disease↗
PubMed2004

A new technology for automatic identification and sorting of plastics for recycling.

A new technology for automatic sorting of plastics, based upon optical identification of fluorescence signatures of dyes, incorporated in such materials in trace concentrations prior to product manufacturing, is described. Three commercial tracers were selected primarily on the basis of their good absorbency in the 310-370 nm spectral band and their identifiable narrow-band fluorescence signatures in the visible band of the spectrum when present in binary combinations. This absorption band was selected because of the availability of strong emission lines in this band from a commercial Hg-arc lamp and high fluorescence quantum yields of the tracers at this excitation wavelength band. The plastics chosen for tracing and identification are HDPE, LDPE, PP, EVA, PVC and PET and the tracers were compatible and chemically non-reactive with the host matrices and did not affect the transparency of the plastics. The design of a monochromatic and collimated excitation source, the sensor system are described and their performances in identifying and sorting plastics doped with tracers at a few parts per million concentration levels are evaluated. In an industrial sorting system, the sensor was able to sort 300 mm long plastic bottles at a conveyor belt speed of 3.5 m.sec(-1) with a sorting purity of -95%. The limitation was imposed due to mechanical singulation irregularities at high speed and the limited processing speed of the computer used.

Automation↗
PubMed2002

The effect of different plasticizer molecular weights and concentrations on mechanical and thermomechanical properties of free films.

Plasticizers are usually added to improve the mechanical and conditional (thermomechanical) quality of film coatings. Different molecular weights and concentrations of polyethylene glycol were incorporated as plasticizers in hydroxypropylmethylcellulose (HPMC) films. Thermomechanical and mechanical properties of cast films were tested using tensile and dynamic mechanical thermal analysis (DMTA) testing, respectively. The results, as expected, showed that addition of plasticizer caused a decrease in both mechanical and thermomechanical properties, but lower grades had more effect than higher molecular weights and concentrations. The conclusion could be drawn that combining different grades of plasticizers to optimize mechanical and thermomechanical properties is more efficient than using different concentrations of plasticizers.

Chemistry, Pharmaceutical↗
PubMed2000

The Evolution of Plasticity and Nonplastic Spatial and Temporal Adaptations in the Presence of Imperfect Environmental Cues.

A model for the evolution of plasticity is considered in which the phenotype, undergoing stabilizing selection, is modeled as a linear function of an environmental cue correlated with the phenotypic optimum, with the coefficients z0 and z1 evolving according to standard quantitative genetic theory. In contrast to previous theoretical models, as the rate of migration between demes or the rate of cyclic fluctuations in the optimum increases, the amount of plasticity [Formula: see text] at equilibrium is shown to increase gradually, in part accounting for the effect of reduced nonplastic adaptation and reaching a maximum equal to the squared correlation between the environmental cue and the phenotypic optimum. Given that information available to the organism is limited, this bias of the expressed phenotype toward the global optimum is still optimal, however, in a certain decision-theoretic sense. When genetic variation in the plastic component of the trait is small so that spatial or temporal differentiation in plasticity is small, the effect of plasticity on nonplastic adaptation is to reduce the effects of variation in the phenotypic optimum by a factor [Formula: see text] only. Information acquisition costs and joint evolution of sensory systems are discussed.

environmental cues↗
PubMed1996

Detour factors in water and plastic phantoms and their use for range and depth scaling in electron-beam dosimetry.

Average penetration depths and detour factors of 1-50 MeV electrons in water and plastic materials have been computed by means of analytical calculation, within the continuous-slowing-down approximation and including multiple scattering, and using the Monte Carlo codes ITS and PENELOPE. Results are compared to detour factors from alternative definitions previously proposed in the literature. Different procedures used in low-energy electron-beam dosimetry to convert ranges and depths measured in plastic phantoms into water-equivalent ranges and depths are analysed. A new simple and accurate scaling method, based on Monte Carlo-derived ratios of average electron penetration depths and thus incorporating the effect of multiple scattering, is presented. Data are given for most plastics used in electron-beam dosimetry together with a fit which extends the method to any other low-Z plastic material. A study of scaled depth-dose curves and mean energies as a function of depth for some plastics of common usage shows that the method improves the consistency and results of other scaling procedures in dosimetry with electron beams at therapeutic energies.

Electrons↗
PubMed1988

Plastic-embedded endoscopic biopsies. Diagnostic advantages.

As the use of endoscopic biopsy has increased in recent years, the pathologists whose job it is to interpret these small specimens have been asked to give more specific diagnoses. Plastic embedding has proved to be a useful diagnostic tool because it provides better morphology than routine paraffin embedding and because enzyme histochemical and immunohistochemical markers can be used. We applied these techniques to endoscopic biopsies hoping to increase the diagnostic yield. Biopsies from 75 patients were fixed in paraformaldehyde, embedded in methacrylate, and sectioned at 2 mu. These sections were then compared with routine sections from the same patient. Additional special stains were used and enzyme histochemistry, or immunohistochemistry was performed on the plastic- or paraffin-embedded tissue as needed. We found that in 26.7% of the cases, plastic sections resulted in more specific diagnoses than was possible with paraffin sections. When distinguishing lymphomas from poorly differentiated carcinomas, this method provided much better morphologic differentiation and better demonstration of leukocyte common antigen than keratin staining. Identification of B- or T-cell antigens was possible on plastics but not on paraffin. Furthermore, lesions such as histiocytosis X and cryptosporidiosis were more accurately identified. Thus, we found that the plastic-embedded tissue provided all the information yielded by routine paraffin embedding and also improved the diagnostic yield on certain types of neoplastic or infectious processes.

Biopsy↗
PubMed1997

Perceptions and misconceptions of the plastic and reconstructive surgeon.

Little is known about professional perceptions of plastic and reconstructive surgery. In an era of managed health care and social reform, public perception, or misconception, may ultimately have a significant impact on this specialty. A survey was conducted to provide some initial evidence for the scope and scale of the misconceptions. Three populations were surveyed for this study: consecutive patients visiting a primary-care facility, medical students, and primary-care physicians. The survey addressed various aspects of plastic surgery-reconstruction, hand, craniofacial, and aesthetic surgery. One thousand one hundred twenty-one individuals of various ages, education levels, and ethnic backgrounds participated in this study. Our data demonstrate that public perception of the plastic and reconstructive surgeon is limited and grossly underestimates this specialty. Although the plastic surgeon is associated with reconstructive surgery, they are not necessarily identified as primary surgeons for procedures fundamental to this specialty. Furthermore, a significant number of respondents would prefer a cosmetic surgeon for aesthetic procedures. We believe that it is crucial that the public, physicians, and medical establishments (e.g., insurance companies, hospital administrations) be educated on the essence of plastic and reconstructive surgery.

Adult↗
PubMed1996

Physiological plasticity in the auditory system and its possible relevance to hearing aid use, deprivation effects, and acclimatization.

Alterations in the physiological and/or the anatomical properties of the central auditory system (neural plasticity) can be induced by unilateral or bilateral sensorineural hearing loss, auditory stimulation, and conditioning in which sounds are used as conditioned stimuli. These types of neural plasticity have implications for hearing aid use, acclimatization, and deprivation effects. The occurrence of hearing-loss-induced plasticity suggests that the organization of the central auditory system may be altered by the time a hearing aid is fitted. The success of hearing aids may depend, therefore, on how the auditory system responds to the reintroduction of certain sounds by amplification. For example, enhanced auditory stimulation provided by hearing aids may induce "secondary" plasticity in the auditory system, which might contribute to acclimatization and/or deprivation effects. Such functional changes might be further modulated by reinforcing responses to reintroduced sounds using conditioning techniques. This article reviews relevant literature on auditory system plasticity--drawn largely from animal research--with the goal of providing insight into possible mechanisms of acclimatization and deprivation effects.

Brain↗
PubMedDate not supplied

National plastic surgical nursing survey.

An understanding of the scope and nature of negative psychological complications resulting from plastic surgery is vital. This knowledge is essential to improve the complex interactions that patients experience as part of their surgical intervention. This is a national survey of patients' psychological complications reported by 312 board certified plastic surgical nurses. Perceived patient psychological complications were reported at a higher rate than perceived physical complications (p > .001), with peri-operative complications of anxiety and mild depression being most prevalent. Less frequent psychological complications included patient disappointment and severe depression. Not surprisingly, surgical site pain and nonspecific physical distress were the most frequent physical complications; sleep disturbance was common. Psychological complications occur at higher rates than do physical complications in plastic surgical practices. Patients with pre-existing psychological conditions are more at risk for peri-operative psychological complications. Nurses should be adequately prepared to screen, support, and coordinate psychological treatment for plastic surgery patients with the plastic surgeon.

Counseling↗
PubMed1985

Victor von Bruns (1812-1883) and his contributions to plastic and reconstructive surgery.

Victor von Bruns was an active surgeon in Germany during the nineteenth century. His work is accompanied by many illustrations, and a selected few are presented in this survey. His original contributions to plastic and reconstructive surgery are notable, mainly in lip and cheek reconstruction. These are still valid today and have been adopted by many plastic surgeons. His books dealt not only with plastic surgery, but with almost every surgical event, such as amputation, larynx surgery, galvanosurgery, and war surgery. His publications and illustrations give an excellent picture of the advances made by him and other plastic surgeons during the second half of the nineteenth century, thus making him an important contributor to the renaissance of plastic surgery.

Cheek↗
PubMed1995

The image of plastic surgeons in news media coverage of the silicone breast implant controversy.

We analyzed the portrayal of plastic surgeons in the media by using the qualitative method of narrative analysis of newspaper articles available between July 1991 and June 1992 and popular magazine articles available from 1965 through 1992 in the Tampa Bay area. Plastic surgeons were presented as antagonists in the "horror stories" of sick women, as combatants in a medical community divided in its assessment of health risks, and as profit-oriented businesspersons. Patients were fully developed heroines, whereas plastic surgeons were described negatively by their antagonists, which undermines the expertise, good character, and good will that determine credibility for plastic surgeons. Providing the press with stories about their own efforts to help patients might have helped plastic surgeons receive more favorable press and enhance their credibility. More sophisticated handling of underlying values and the problem of communicating safety also might have been helpful.

Breast Implants↗
PubMed1997

Plastic surgeons: a gender comparison.

This study surveyed plastic surgeons for the purpose of identifying gender-related differences within the specialty. A confidential 108-item questionnaire was mailed to all female members and candidates of the American Society of Plastic and Reconstructive Surgeons (ASPRS) and to an equal number of male colleagues. The survey was conducted between September of 1992 and October of 1993 using a modified Dillman five-step computerized method. The response rate was 73 percent for women (157 of 216) and 57 percent for men (124 of 216). Of those who responded, 65 percent of women and 89 percent of men were married (p < 0.01). Fifty-two percent of women and 86 percent of men had biologic children (p < 0.001). The majority of surgeons surveyed (97 percent) were in full-time surgical practice. Many women reported delaying childbearing until they had begun full-time practice of plastic surgery (p < 0.001). No significant gender-related differences were noted with respect to medical school rank, training history, advanced degrees, subspecialty practiced, hospital affiliation, or hours worked. Women surgeons in academic practice held lower rank than men and were less likely to be tenured (p < 0.04). Gross annual income was lower for women (p < 0.001). In contrast to men (27 percent), most women (89 percent) perceived sexual discrimination and harassment (p < 0.001). The majority of plastic surgeons were satisfied with their financial situation (80 percent), work (94 percent), and family life (76 percent). Over 90 percent of both women and men were happy with their career choice and would encourage medical students to become surgeons. Plastic surgeons do not differ in training or professional practice characteristics. Discrimination and harassment and unequal promotion and remuneration of women in the university environment are problems that need to be eliminated.

Adult↗
PubMed1998

Survey of factors influencing the selection of academic plastic surgeons.

The purpose of this study was to evaluate the importance of factors influencing the selection of candidates for academic positions in plastic surgery. This study reports the results of a survey investigating these factors. The survey was conducted in 1994, canvassing the chairpersons from the 120 plastic surgery programs in the United States and Canada with responses from 91 (76 percent) of the plastic surgery programs. The study examined individual accomplishments and areas of additional training. Training in a specific area of clinical interest, clinical and basic science experience, and training in cosmetic surgery were the most highly rated areas of additional training. The ideal time to receive this training was also assessed for each area of additional training. Postgraduate degrees in basic science, epidemiology, or clinical research were not highly rated. The highest rated personal accomplishments were the personal interview, letter of reference from the program chairperson, publications, and presentations. Despite the survey's attempt to evaluate factors other than personal characteristics (i.e., honesty, integrity, affability, etc.) more than 25 percent of the respondents indicated that these attributes are highly rated and cannot be judged separately. The information collected in this survey represents an opinion from 1994, which defines some of the factors that are considered important when residents and newly trained plastic surgeons are considering a career in academic plastic surgery.

Academic Medical Centers↗
PubMed1998

The changing health care marketplace: current industry trends, new provider organizational structures, and effects on plastic surgeons.

Current market forces are driving the health care industry in new directions. The managed care industry is currently undergoing a market shakeout, as manifested by consolidation, increased competition, and lower profits. Medicare is fighting to remain solvent by lowering fees paid to providers, driving patients into managed care plans, and cracking down on billing irregularities. For providers, the combined effect of these trends is lower fees, increased risk-sharing, and increased overhead. Plastic surgeons face new demands in this environment. They must increase their efficiency and form new alliances with other providers. These alliances allow plastic surgeons to maintain a steady stream of patients, to manage risk, to negotiate more lucrative contracts with managed care organizations, and to increase efficiency. To achieve these alliances, plastic surgeons must alter the organizational structure of their practices. Several corporate practice models are becoming more prevalent; these include large group practices, physician practice management companies, and integrated delivery systems. Each structure has advantages for plastic surgeons, but each also requires plastic surgeons to trade varying degrees of financial and professional autonomy for market strength.

Forecasting↗
PubMed2000

Wall Street's assessment of plastic surgery--related technology: a clinical and financial analysis.

Many plastic surgeons develop technologies that are manufactured by Wall Street-financed companies. Others participate in the stock market as investors. This study examines the bioengineered skin industry to determine whether it integrates clinical and financial information as Wall Street tenets would predict, and to see whether the financial performance of these companies provides any lessons for practicing plastic surgeons. In efficient markets, the assumptions on which independent financial analysts base their company sales and earnings projections are clinically reasonable, the volatility of a company's stock price does not irrationally differ from that of its industry sector, and the buy/sell recommendations of analysts are roughly congruent. For the companies in this study, these key financial parameters were compared with a benchmark index of 69 biotech companies of similar age and annual revenues (Student's t test). Five bioengineered skin companies were included in the study. Analysts estimated that each company would sell its product to between 24 and 45 percent of its target clinical population. The average stock price volatility was significantly higher for study companies than for those in the benchmark index (p < 0.05). Similarly, buy/sell recommendations of analysts for the study companies were significantly less congruent than those for the benchmark companies (p < 0.05). These results indicate clinically unrealistic projections for market penetration, significantly high price volatility, and significantly high discordance among professional analysts. In all cases, the market is inefficient-an unusual finding on Wall Street. A likely explanation for this market failure is a cycle of poor clinical correlation when assigning sales projections, which in turn leads to price volatility and discordance of buy/sell recommendations. This study's findings have implications for plastic surgeons who develop new technology or who participate in the equities markets as investors. Plastic surgeons who develop new medical devices or technology cannot universally depend on the market to drive clinically reasonable financial performance. Although inflated sales estimates have benefits in the short term, failure to meet projections exacts severe financial penalties. Plastic surgeons who invest in the stock market, because of their unique clinical experience, may sometimes be in the position to evaluate new technologies and companies better than Wall Street experts. Well-timed trades that use this expertise can result in opportunities for profit.

Biomedical Engineering↗
PubMed2003

Safety and efficacy in an accredited outpatient plastic surgery facility: a review of 5316 consecutive cases.

Advances in medicine have improved the delivery of health care, making it more technologically superior than ever and, at the same time, more complex. Nowhere is this more evident than in the surgical arena. Plastic surgeons are able to perform procedures safely in office-based facilities that were once reserved only for hospital operating rooms or ambulatory surgery centers. Performing procedures in the office is a convenience to both the surgeon and the patient. Some groups have challenged that performing plastic surgery procedures in an office-based facility compromises patient safety. Our study was done to determine whether outcomes are adversely affected by performing plastic surgery procedures in an accredited outpatient surgical center. A retrospective review was performed on 5316 consecutive cases completed between 1995 and 2000 at Dallas Day Surgical Center, Dallas, Texas, an outpatient surgical facility. Most cases were cosmetic procedures. All cases were analyzed for any potential morbidity or mortality. Complications requiring a return to the operating room were determined, as were infection rates. Events leading to inpatient hospitalization were also included. During this 6-year period, 35 complications (0.7 percent) and no deaths were reported. Most complications were secondary to hematoma formation (77 percent). The postoperative infection rate for patients requiring a return to the operating room was 0.11 percent. Seven patients required inpatient hospitalization following their procedure secondary to arrhythmias, angina, and pulmonary emboli. Patient safety must take precedence over cost and convenience. Any monetary savings or time gained is quickly lost if safety is compromised and complications are incurred. The safety profile of the outpatient facility must meet and even exceed that of the traditional hospital-based or ambulatory care facility. After reviewing our experience over the last 6 years that indicated few complications and no deaths, we continue to support the judicious use of accredited outpatient surgical facilities by board-certified plastic surgeons in the management of plastic surgery patients.

Ambulatory Surgical Procedures↗