Current concepts of fluid management in enhanced recovery pathways.

Perioperative fluid management impacts outcomes and plays a pivotal role in enhanced recovery pathways (ERPs). There have been major advances in understanding the effects of fluid therapy and administration during the perioperative period. Improving fluid management during this period leads to a decrease in complications, decrease in length of stay (LOS), and enhanced patient outcomes. It is important to consider preoperative and postoperative fluid management to be just as critical as intraoperative management given multiple associated benefits to the patients. Preoperative hydration with (complex) carbohydrate drinks up until 2 h before surgery is safe and should be encouraged, as this helps improve metabolism, decrease insulin resistance, reduce anxiety, and reduce nausea and vomiting. During the intraoperative period, the goals of fluid management are to maintain euvolemia using an individualized plan for fluid and haemodynamic management, matching the needs for monitoring with patient and surgical risk through goal-directed therapy (GDT). By combining the use of fluids and inotropes, GDT uses measurements and indicators of cardiac output and stroke volume to improve blood flow intraoperatively, and ultimately reduce LOS and complications. In the postoperative period, an early transition to oral hydration helps to enhance the conditions for healing and recovery from surgery. I.V. fluid therapy should be kept at a minimum, and urine output should not be the driving force for fluid administration. The optimization of perioperative fluid management is critical to ERPs as it helps improve pulmonary function, tissue oxygenation, gastrointestinal motility, and wound healing.

Astronomical time-of-flight photon speedometer.

A dual-band, fiber-optic, photon time-of-flight instrument was developed. Its design was optimized for measuring the velocity of visible photons emanating from relatively dim astronomical sources (apparent magnitude m>12), such as distant galaxies and quasars. We report the first direct photon group velocity measurements for extragalactic objects. The photon group velocity is found to be 3.00±0.03×108 ms-1 and is invariant, within experimental error, over the range of redshifts measured (0≤z≤1.33). This measurement provides additional validation of general relativity and is consistent with the Friedmann-Lemaître-Robertson-Walker and hyperbolic anti-de Sitter metrics but not with the elliptical de Sitter metric.

The ghost of competition present.

Communities have been viewed as the end product of an assembly process that results in increasing stability through time as progressively better competitors eventually dominate the other species that can emigrate from a regional pool. Previous work has explained species assemblages based on the traits of the successful species. We suggest that the traits of unsuccessful species in the regional pool may also be important for understanding which species are successful in communities. We constructed a simulation model to study what distinguishes stable, uninvasible assemblages from other possible assemblages from a regional pool of species. Our model demonstrates that both the interactions among the successful species and the interactions between these species and unsuccessful species attempting to invade the community contribute significantly to determining success in the final stable community. Understanding the structure of natural communities may require some knowledge of the unobserved "ghost" species that fail to establish in that same community yet still have significant effects on structure.

Touch contamination levels during anaesthetic procedures and their relationship to hand hygiene procedures: a clinical audit.

After different methods of hand preparation, volunteers rolled segments of sterile central venous catheter between their fingertips, and bacterial transfer was evaluated by standardized quantitative culture. The number of bacteria transferred differed between methods (P<0.001). Comparisons were made with the control group (no preparation at all; median, third quartile and maximum count=6.5, 24, 55). Bacterial transfer was greatly increased with wet hands (1227, 1932, 3254; P<0.001). It was reduced with a new rapid method, based on thorough drying with a combination of 10 s using a cloth towel followed by either 10 or 20 s with a hot-air towel (0, 3, 7 and 0, 4, 30, respectively; P=0.007 and 0.004, respectively). When asked to follow their personal routines, 10 consultant anaesthetists used a range of methods. Collectively, these were not significantly better than control (7.5, 15, 55; P=0.73), and neither was an air towel alone (2.5, 15, 80; P=0.176) nor the hospital's standard procedure (0, 1, 500; P=0.035). If hand preparation is needed, an adequate and validated method should be used, together with thorough hand drying.

Disclosing doctors' incentives: will consumers understand and value the information?

As part of a broader movement toward accountability in health care, federal and state governments have required health plans to disclose physicians' financial incentives. Available data suggest that patients have poor comprehension of the incentives and significant barriers to learning, including high trust in their physicians, reluctance to think of the physician/patient relationship in financial terms, and failure to understand the relevance of the information to their health care choices and treatment. Disclosure that conveys clearly what is at stake will increase the salience of incentive information but is also more likely to erode trust.

Assessment of skin absorption and penetration of JP-8 jet fuel and its components.

Dermal penetration and absorption of jet fuels in general, and JP-8 in particular, is not well understood, even though government and industry, worldwide, use over 4.5 billion gallons of JP-8 per year. Exposures to JP-8 can occur from vapor, liquid, or aerosol. Inhalation and dermal exposure are the most prevalent routes. JP-8 may cause irritation during repeated or prolonged exposures, but it is unknown whether systemic toxicity can occur from dermal penetration of fuels. The purpose of this investigation was to measure the penetration and absorption of JP-8 and its major constituents with rat skin, so that the potential for effects with human exposures can be assessed. We used static diffusion cells to measure both the flux of JP-8 and components across the skin and the kinetics of absorption into the skin. Total flux of the hydrocarbon components was 20.3 micrograms/cm(2)/h. Thirteen individual components of JP-8 penetrated into the receptor solution. The fluxes ranged from a high of 51.5 micrograms/cm(2)/h (an additive, diethylene glycol monomethyl ether) to a low of 0.334 micrograms/cm(2)/h (tridecane). Aromatic components penetrated most rapidly. Six components (all aliphatic) were identified in the skin. Concentrations absorbed into the skin at 3.5 h ranged from 0.055 micrograms per gram skin (tetradecane) to 0.266 micrograms per gram skin (undecane). These results suggest: (1) that JP-8 penetration will not cause systemic toxicity because of low fluxes of all the components; and (2) the absorption of aliphatic components into the skin may be a cause of skin irritation.

The production and characterization of recombination between chromosome 3N of Aegilops uniaristata and chromosome 3A of wheat.

Six wheat lines with recombination between Aegilops uniaristata chromosome 3N and wheat chromosome 3A were produced. These were characterized in terms of exchange points by RFLP analysis. Chromosome 3N carries an undesirable brittle rachis gene and three of the recombinant lines had lost this character. The results also support previously published evidence of a pericentric inversion in chromosome 3N relative to the wheat homoeologous group 3 chromosomes.

Assessing the feasibility of an in vitro cytotoxicity method to detect harmful ubiquitous chemicals (detection of non-warfare hazardous chemicals in the operational theater).

The objective of this work was to assess the feasibility of accomplishing aqueous extracts of soil samples and determining if the extracted solution induced adverse effects in the human myelomonocytic cell line, HL60. Dosing of HL60 cells was accomplished over a 24-hour period using 100% of extracted media from standard soil samples containing known contaminants. Assessments of viability, apoptosis, reduced thiols, and mitochondrial membrane integrity were accomplished by argon-ion laser flow cytometric analysis, using chemical labels specific for each end-point. The in vitro cytotoxicity data was compared with the results of Microtox and Mutatox tests as well as earthworm and plant toxicity tests. In vitro cytotoxicity tests' results exhibited good correlation with other tests' results.

Induction and characterization of Ph1 wheat mutants.

The cloning of genes for complex traits in polyploid plants that possess large genomes, such as hexaploid wheat, requires an efficient strategy. We present here one such strategy focusing on the homologous pairing suppressor (Ph1) locus of wheat. This locus has been shown to affect both premeiotic and meiotic processes, possibly suggesting a complex control. The strategy combined the identification of lines carrying specific deletions using multiplex PCR screening of fast-neutron irradiated wheat populations with the approach of physically mapping the region in the rice genome equivalent to the deletion to reveal its gene content. As a result, we have located the Ph1 factor controlling the euploid-like level of homologous chromosome pairing to the region between two loci (Xrgc846 and Xpsr150A). These loci are located within 400 kb of each other in the rice genome. By sequencing this region of the rice genome, it should now be possible to define the nature of this factor.

Optical spectroscopic characterization of single tryptophan mutants of chicken skeletal troponin C: evidence for interdomain interaction.

The effects of metal ion binding on the optical spectroscopic properties and temperature stability of two single tryptophan mutants of chicken skeletal TnC, F78W and F154W, have been examined. The absence of tyrosine and other tryptophan residues allowed the unambiguous assignment of the spectral signal from the introduced Trp residue. Changes in the molar ellipticity values in the far-UV CD spectra of the mutant proteins on metal ion binding were similar to those of wild-type TnC suggesting that the introduction of the Trp residue had no effect on the total secondary structure content. The fluorescence and near-UV absorbance data reveal that, in the apo state, Trp-78 is buried while Trp-154 is exposed to solvent. Additionally, the highly resolved (1)L(b) band of Trp-78 seen in the near-UV absorbance and CD spectra of the apo state of F78W suggest that this residue is likely in a rigid molecular environment. In the calcium-saturated state, Trp-154 becomes buried while the solvent accessibility of Trp-78 increases. The fluorescence emission and near-UV CD of Trp-78 in the N-terminal domain were sensitive to calcium binding at the C-terminal domain sites. Measurements of the temperature stability reveal that events occurring in the N-terminal domain affect the stability of the C-terminal domain and vice versa. This, coupled with the titration data, strongly suggests that there are interactions between the N- and C-terminal domains of TnC.

Disclosing physician financial incentives.

Federal and state regulatory initiatives as well as court decisions increasingly require managed care organizations to disclose physician financial incentives and have raised the issue of disclosure by physicians themselves. These mandates are based on ethical and legal principles arising from the patient-physician relationship and the relationship between health plan sponsors and enrollees. Disclosing incentives also serves important policy objectives: it can inform enrollees' choice of plan, reinforce enrollees' capacity to understand and exercise other rights under managed care, and discourage use of compensation methods that might compromise patients' access to treatment. However, significant conceptual and practical questions remain about implementing a disclosure mandate. Unresolved issues include the timing, content, and scope of disclosure, the relationship of disclosure to patients' substantive rights, and the impact of disclosure on trust between patients and physicians. These uncertainties exemplify the challenges facing policymakers, plans, and physicians as they determine how best to inform patients about managed care.

Dietary chitosan inhibits hypercholesterolaemia and atherogenesis in the apolipoprotein E-deficient mouse model of atherosclerosis.

Chitosan, the deacetylated form of chitin, is extracted from the shells of crustaceans. The strong positive charge carried by the chitosan molecule causes it to bind negatively charged substrates such as lipids. Orally administered chitosan binds fat in the intestine, blocking absorption, and has been shown to lower blood cholesterol in animals and humans. As a result it has been proposed that dietary supplementation with chitosan may inhibit the formation of atherosclerotic plaque. We have tested this hypothesis using the apolipoprotein E-deficient mouse model of atherosclerosis. This hypercholesterolaemic animal develops atherosclerosis without the need for dietary or surgical intervention. The apolipoprotein E-deficient mouse therefore provides an ideal model in which to study the effects of dietary chitosan on both blood cholesterol and atherosclerosis. Animals were fed for 20 weeks on a diet containing 5% chitosan or on a control diet. Blood cholesterol levels were significantly lower in the chitosan fed animals throughout the study, and at 20 weeks were 64% of control levels. When the area of aortic plaque in the two groups was compared a highly significant inhibition of atherogenesis, in both the whole aorta and the aortic arch, was observed in the chitosan fed animals--42 and 50%, respectively. Body growth was significantly greater in the chitosan fed animals. This study is the first to show a direct correlation between lowering of serum cholesterol with chitosan and inhibition of atherogenesis, and suggests that the agent could be used to inhibit the development of atherosclerosis in individuals with hypercholesterolaemia.

Developmental exposure to lead causes persistent immunotoxicity in Fischer 344 rats.

Lead has been shown to exert toxic effects during early development. In these in vivo and ex vivo experiments, the effect of lead on the immune system of the developing embryo was assessed. Nine-week-old female Fischer 344 rats were exposed to lead acetate (0, 100, 250, and 500 ppm lead) in their drinking water during breeding and pregnancy (exposure was discontinued at parturition). Offspring received no additional lead treatment after birth. Immune function was assessed in female offspring at 13 weeks of age. Dams in lead-exposed groups were not different from controls with respect to the immune endpoints used in these experiments; however, in the offspring, lead modulated important immune parameters at modest exposure levels. Macrophage cytokine and effector function properties (tumor necrosis factor-alpha and nitric oxide production) were elevated in the 250 ppm group, while cell-mediated immune function was depressed, as shown by a decrease in delayed-type hypersensitivity reactions in the 250 ppm group. Interferon-gamma levels were decreased in the 500 ppm treatment group. Serum levels of IgE were increased in rats exposed to 100 ppm lead. These results indicate that exposure of mothers to moderate levels of lead produces chronic immune modulation in their F344 rat offspring exposed in utero. Since the mothers were not susceptible to chronic immune alterations, a developmental bias to the immunotoxic effects of lead is indicated. The differences observed are consistent with the possibility that lead may bias T helper subset development and/or function, resulting in alterations in the balance among type 1 and type 2 immune responses.

Managed care regulation: in the laboratory of the states.

In the wake of failed national health care system reform, the responsibility of crafting public policy to respond to changes in the health care system has fallen largely to state governments. Beginning in 1995, state policymakers focused intensively on managed care regulation, adopting policies on a broad array of issues with important implications for patients, physicians, and the physician-patient relationship. To a surprising degree, the regulatory activity in diverse health care markets across the nation has reflected a shared set of concerns about managed care practices and trends. An evaluation of the impact of these state policies will provide essential information about the most effective role for government in promoting the physician-patient relationship and the rights of patients and health care professionals in the era of managed care.