A fever workup guideline

Fever is a common clinical problem in patients hospitalized with trauma. When an infection is suspected, it is important to identify the source of fever and begin definitive care before more severe morbidity occurs. An undirected approach with "pan cultures" has resulted in a high rate of negative cultures obtained and has increased patient care costs. By developing and using an evidence-based fever workup guideline, this institution was able to evaluate and identify infections and reduce costs.     

Potential human and economic cost-savings attributable to vision testing policies for driver license renewal, 1989-1991

PURPOSE: This study assessed the impact of vision-related relicensing policies on traffic fatalities in the United States. There is a limited empirical basis for state vision testing policies for relicensing. Furthermore, it is uncertain whether contemporary vision standards for driver licensing achieve their implicit goal of protecting the public's health, or inappropriately restrict the mobility of competent drivers. METHODS: The 48 contiguous states and the District of Columbia were the "subjects" in this investigation. During the study period (1989 to 1991), 10 states did not require vision testing for driver license renewal. Multiple regression modeling was used to assess the impact of vision-related relicensing policies on traffic safety and to estimate the number of avoidable vehicle occupant fatalities and corresponding economic costs associated with traffic crashes involving older drivers (> or = 60 years). The primary data source for this investigation was the Fatal Accident Reporting System (FARS) database. RESULTS: Vision-related relicensing policies were significantly associated (p < 0.05) with lower vehicle occupant fatality rates of older drivers. According to the final regression model, approximately 222 fewer vehicle occupant fatalities (-12.2%) associated with older drivers would be expected for the 3-year period if mandatory vision testing policies had been in effect in 8 of the 10 states without such policies. Conservatively, those avoidable deaths represent an estimated $31 million in avoidable economic costs. CONCLUSIONS: State-level mandatory vision testing for relicensure may enhance traffic safety and reduce the economic burden of fatal crashes. Vision testing requirements should be maintained by jurisdictions with such requirements, and jurisdictions without such requirements should consider the potential traffic safety benefits of vision testing for driver license renewal.     

Endothelium-dependent contractile actions of proteinase-activated receptor-2-activating peptides in human umbilical vein: release of a contracting factor via a novel receptor

The contractile actions of the proteinase-activated receptor-2-activating peptides (PAR2APs), SLIGRL-NH2 (SL-NH2), SLIGKV-NH2 (KV-NH2), trans-cinnamoyl-LIGRLO-NH2 (tc-NH2), and the PAR1-AP. TFLLR-NH2 (TF-NH2) as well as trypsin and thrombin were studied in endothelium-denuded and intact human umbilical vein (HUV) ring preparations. In HUV rings with, but not without an intact endothelium, PAR2APs caused a concentration-dependent contractile response, whereas LSIGRL-NH2 trypsin and PAR1APs were inactive. The contractile response was not affected by the endothelin ETA receptor antagonist, BQ123, the cyclooxygenase inhibitor, indomethacin, the leukotriene synthesis inhibitor, MK886, or the epoxygenase/P450 inhibitor, SKF-525A. Other pharmacological antagonists (prazosin, Losartan") were similarly inactive. The order of potencies of the PAR2APs to cause a contraction in the endothelium-intact preparation was: SL-NH2 > > KV-NH2 > or = tc-NH2. Using an endothelium-free rat aorta ring as a reporter tissue, surrounded with endothelium-intact HUV as a donor tissue in a 'sandwich assay,' we also monitored the ability of SL-NH2, TF-NH2, trypsin and thrombin to release either contractile (EDCF) or relaxant (EDRF) factors. In the 'sandwich assay' done in the presence of L-NAME (0.1 mM), the endothelium-intact HUV tissue (but not endothelium-denuded HUV) released a contractile factor (EDCF) in response to SL-NH2 (50 microM) but not to trypsin or LSIGRL-NH2. The SL-NH2-mediated release/action of the EDCF was not affected by BQ123, indomethacin, MK886 or SKF-525A. In the 'sandwich assay', trypsin (4-10 nM), SL-NH2, KV-NH2 and tc-NH2 caused the release of a relaxant activity (EDRF) from the endothelium-intact (but not the denuded) HUV preparation. The release of EDRF was blocked by 0.1 mM (omega)nitro-L-arginine-methylester (L-NAME). Neither thrombin (10 u ml(-1), 100 nM) nor TF-NH2 (50 microM) were active in this EDRF-release assay. The relative potencies of the PAR2 agonists for causing the release of EDRF in the HUV sandwich assay were: trypsin> >SL-NH2> >tc-NH2>KV-NH2. This order of potencies differed from the one observed for the same agonists in the HUV contraction assay (above) and in an intracellular calcium signalling assay, conducted with cloned human PAR2 that was expressed in cultured rat kidney KNRK cells: trypsin > > SL-NH2 = tc-NH2 > KV-NH2. We conclude that PAR2APs (but not PAR1APs) via a receptor distinct from PAR2, can cause a contractile response in endothelium-intact HUV tissue via the release of a diffusable EDCF, that is different from previously recognized smooth muscle agonists (e.g. prostanoid metabolites, endothelin, noradrenaline, angiotensin-II, acetylcholine).     

Minimally invasive repair of atrial septal defects

BACKGROUND: Minimally invasive pediatric cardiac surgical techniques continue to evolve and remain challenged by technologic advances in percutaneous devices developed to treat congenital heart disease exclusive of cardiopulmonary bypass. Public tenacity for "incisionless" operations, however, must remain balanced scrupulously against the collective safety of the surgical procedure. METHODS: Twenty-three pediatric patients underwent repair of atrial septal defects through a partial sternal split and a limited skin incision (5 to 7 cm) at our institution between July 1995 and October 1996. RESULTS: The average age of the patients was 6 years and 2 months (range, 19 months to 15 years) and the average weight was 23.3 kg (range, 11.3 to 61.7 kg). The average bypass time was 35 minutes (range, 19 to 81 minutes). Fourteen patients had a single dose of blood cardioplegia administered, whereas 9 had ventricular fibrillation electrically induced. Twenty-two patients had ostium secundum defects and 1 had a sinus venosus defect. The average length of the hospital stay was 3.6 days (range, 3 to 6 days). There were no operative or late deaths. CONCLUSIONS: Modifications of this technique continue to evolve as an effective cosmetic alternative to submammary and thoracotomy approaches. Advantages of this modification include excellent cosmetic results in all age groups and the concomitant security and familiarity of mediastinal access and full sternotomy when required.     

Deceiving others/deceiving oneself: four cases of factitious rape

Although patients with factitious disorders typically seek the "patient" role through illness portrayals, some instead portray themselves falsely as "victims." We discuss the cases of four women who claimed to have been victims of rape; the allegations ultimately were disproved. Factitious rape may be prompted by a search for nurturance; by dissociation, leading individuals to believe that trauma earlier in life is ongoing; by a need to be rescued from real, current abuse; and by projection of anger onto specific male targets. Although dramatic, factitious rape is rare, we advocate thorough investigation of rape claims even when patients have known histories of deceptive behavior.     

Mathematical models of marrow cell kinetics: differential effects of protracted irradiations on stromal and stem cells in mice

It is known that hematopoiesis is supported by bone-marrow stem cells, but those cells must seed and grow on a stromal microenvironment. Typically, studies have shown that a surviving fraction of about 30 hematopoietic stem cells (HSCs) (i.e., about 0.04%) correspond to the LD50, although other studies have shown that marrow can repopulate from a single viable cell under strong regiments of antibiotics and infusions of irradiated blood elements. PURPOSE: This paper describes comparisons between our results (from maximum-likelihood estimation techniques for cellular damage, repair, and compensatory repopulation) and published experimental data on marrow stromal cells. METHODS AND MATERIALS: After biophysical consideration of the rate constants that were derived by maximizing the likelihood function (a consideration necessary to extend the model to cell populations not indicated by the model as "critical" for recovery), the rate constants for cellular damage to stem cells are fitted to experimental data. Rate constants for repair and proliferation of stem cells are assigned based on published data on repair/proliferation half-times, and these assignments affect the evaluation of the rate constants for cellular damage. From the two models, that is one for "critical" cells (having radiosensitive and repopulation characteristics similar to stromal cells) and another for stem cells, effects on two cell populations of different radiosensitivities and repopulation rates can be demonstrated for complex schedules of protracted irradiations which could reduce either cell population below a critical need for marrow repopulation. RESULTS: Our analysis of animal mortality data has indicated that recovery of an animal from potentially lethal irradiation is dominantly regulated by cells with survival and repopulation characteristics similar to those of stroma cells. CONCLUSION: In contrast to the surviving fraction of hematopoietic stem cells, it appears that the probability of an animal's recovery is high if the "critical" population of cells is above 1% (our "best" maximum likelihood estimate, from mouse data, with the corresponding lower confidence bound at about 0.2%). Of course, a few stem cells--perhaps only one--must maintain a potential for repopulation of blood and marrow.     

Improved tracking of time-varying encoding properties of visual neurons by extended recursive least-squares.

Traditional approaches to characterizing the transformation from stimulus to response in sensory systems assume both stationarity of the stimulus and time-invariance of the stimulus/response mapping. However, recent studies of sensory function under natural stimulus conditions have demonstrated important features of neural encoding that are in violation of these assumptions. Many sensory neurons respond to changes in the statistical distribution of the stimulus that are characteristic of the natural environment with corresponding changes in their encoding properties. In this paper, an extended recursive least-squares (ERLS) approach to adaptive estimation from stimulus/response observations is detailed. The ERLS approach improves the tracking ability of standard RLS approaches to adaptive estimation by removing a number of assumptions about the underlying system and the stimulus environment. The ERLS framework also incorporates an adaptive learning rate, so that prior knowledge of the relationship between the stimulus and the adaptive nature of the system under investigation can be used to improve tracking performance. Simulated and experimental neural responses are used to demonstrate the ability of the ERLS approach to track adaptation of encoding properties during a single stimulus/response trial. The ERLS framework lends tremendous flexibility to experimental design, facilitating the investigation of sensory function under naturalistic stimulus conditions.     

Calculation of the extreme ultraviolet radiation of the earth's plasmasphere

The dynamic global core plasma model(DGCPM) is used in this paper to calculate the He+ density distribution of the Earth's plasmasphere and to investigate the configurations and 30.4 nm radiation properties of the plasmasphere.Validation comparisons between the simulation results and IMAGE mission observations show:That the equatorial structure of the plasmapause is mainly located near 5.5 RE and the typical scale of plasmasphere shrinking or expansion within 10 min is approximately 0.1 RE;that the plasmasp...     

Diagnostic methods for the detection of subacute ruminal acidosis in dairy cows.

Two experiments were conducted 1) to validate a field protocol for the determination of ruminal pH and 2) to develop a strategy to interpret ruminal pH data from groups of cows. In the first experiment, ruminal fluid was collected from 30 lactating dairy cows. Ruminal fluid pH was 0.28 pH units lower for fluid collected by rumenocentesis than for fluid collected through a ruminal cannula. Concentrations of volatile fatty acids were correspondingly higher in samples collected by rumenocentesis. A portable pH meter capable of measuring pH of a very small volume of ruminal fluid yielded very similar pH readings as did a standard meter with a pH probe. Filtration or aspiration of ruminal fluid had no effect on pH. In the second experiment, a strategy was developed to use ruminal pH values from a subsample of cows to distinguish between groups fed either a low or higher forage diet. Groups could be distinguished using a cut point of 5.5 ruminal pH, a sample size of 12 cows, and a critical value of 3 or more cows below the cut point. This strategy had the lowest theoretical error rate for herds with either a high or low prevalence of cows with a low ruminal pH.