Experimental upper bound and theoretical expectations for parity-violating neutron spin rotation in 4He.

Neutron spin rotation is expected from quark-quark weak interactions in the standard model, which induce weak interactions among nucleons that violate parity. We present the results from an experiment searching for the effect of parity violation via the spin rotation of polarized neutrons in a liquid 4He medium. The value for the neutron spin rotation angle per unit length in 4He, d ϕ / d z = [ + 2.1 ± 8.3 (stat.) - 0.2 + 2.9 (sys.) ] × 10 - 7 rad/m, is consistent with zero. The result agrees with the best current theoretical estimates of the size of nucleon-nucleon weak amplitudes from other experiments and with the expectations from recent theoretical approaches to weak nucleon-nucleon interactions. In this paper we review the theoretical status of parity violation in the n → + 4He system and discuss details of the data analysis leading to the quoted result. Analysis tools are presented that quantify systematic uncertainties in this measurement and that are expected to be essential for future measurements.

A slow neutron polarimeter for the measurement of parity-odd neutron rotary power.

We present the design, description, calibration procedure, and an analysis of systematic effects for an apparatus designed to measure the rotation of the plane of polarization of a transversely polarized slow neutron beam as it passes through unpolarized matter. This device is the neutron optical equivalent of a crossed polarizer/analyzer pair familiar from light optics. This apparatus has been used to search for parity violation in the interaction of polarized slow neutrons in matter. Given the brightness of existing slow neutron sources, this apparatus is capable of measuring a neutron rotary power of dϕ/dz = 1 × 10(-7) rad/m.

Use of geotextile tubes with chemical amendments to dewater dairy lagoon solids.

Three geo-textile filtration tubes were used to dewater lagoon solids from a first stage dairy lagoon using chemical amendments (aluminum sulfate and a polymer) to enhance the separation process. This experiment had previously been done without chemical amendment. The chemical amendments speeded the dewatering process so that filling could be accomplished sooner, and also increased the removal rate of nutrients, especially phosphorus into the solid phase. Chemically amended slurry was pumped from the lagoon into the tube with the filtered liquid seeping from the tube and returning to the lagoon. Each tube was filled five to six times at 2-5-day intervals, and then allowed to dewater for 2 weeks before sampling the solid fraction in the tube. Separation efficiency improved from 79% to 99% for phosphorous and from 92% to 100% for organic nitrogen with chemical amendment. Time required for dewatering was significantly reduced by chemical amendment. Cost for the tube was approximately $10/m(3) of recovered solids with no chemical amendment and cost including the chemicals was approximately $14/m(3) of recovered solids.

Stent thrombosis in the era of drug eluting stents.

Despite a marked reduction in restenosis and the need for repeat revascularization procedures with the use of drug-eluting stents (DES), the risk for stent thrombosis remains of serious concern. Although the safety profiles of DES dose not seem to differ from those of bare metal stent (BMS) in the acute and subacute phases following coronary intervention, recent data suggest a potential increase of thrombotic events late after DES deployment. The main factors associated with late stent thrombosis remain elusive. Delayed re-endothelialization, hypersensitivity reaction, technical and mechanical factors and hypercoagulability have all been proposed as contributing factors. It is unlikely that any of these variables alone can cause stent thrombosis, as the incidence of each factor is much higher than the currently known rates of DES thrombosis. Further, temporal appearances of the thrombotic events represent a challenge to our understanding of re-endothelialization, as one would expect that endothelial coverage would be higher in the later phases after treatment. New expanded definitions of stent thrombosis, which also include events secondary to repeat revascularization, have been proposed to provide a better comparative endpoint between BMS and DES. Such clinical attempt to characterize stent thrombosis is valuable, but does not provide much insight into the pathophysiology and intrinsic thrombotic risk of each device. A true progress in this field will only be possible after we improve our understanding of the patho-physiology of very late stent thromboses, which may differ from events occurring earlier after treatment. The incidence of stent thrombosis remains rare, but its potential catastrophic consequences should remind clinicians and scientists to make every effort to develop strategies and technologies for its prevention. The topic of stent thrombosis in the era of DES will be reviewed in this article.

Percutaneous coronary intervention of bifurcation coronary disease.

Bifurcation coronary artery disease is a frequent problem faced by interventional cardiologists and it affects approximately 15-20% of patients undergoing percutaneous coronary intervention (PCI). The application of drug-eluting stents (DES) technology to prevent restenosis after PCI represents one of the success stories in cardiology, but DES have not resolved the bifurcation PCI challenge. Bifurcation PCI remains associated with higher procedural failure and worse outcomes compared with PCI of non-bifurcated lesions even in DES era. A dependable strategy for PCI of bifurcation lesions has yet to be established, which is likely due to the paucity of studies evaluating the anatomical intricacies of the bifurcation as well as the lack of large scale randomized therapeutic trials. Further, bifurcation has many anatomical variants and it is unlike that one technique will fit all. Currently, we are left with the option of a tailor-made strategy for each patient and bifurcation anatomy and make the most of the limited evidence available to support our therapeutic decisions. In this review, we attempted to describe the current understanding of bifurcation anatomy and corresponding PCI strategies.

Usefulness of cardiac magnetic resonance imaging for coronary artery disease detection.

Cardiac magnetic resonance imaging (cMRI) is a promising non-invasive technique to assess the presence of coronary artery disease (CAD), which is free of ionizing radiation and iodine contrast. cMRI can detect CAD by angiographic methods or indirectly by perfusion stress techniques. While coronary angiography by cMRI remains limited to research protocols, stress perfusion cMRI is currently being applied worldwide in the clinical setting. Studies have shown good correlation between adenosine-induced stress myocardial perfusion cMRI and single-photon-emission computed tomography or positron emission tomography to detect CAD. Quantitative methods to analyze cMRI perfusion data have been developed in an attempt to provide a more objective imaging interpretation. Standardization of such quantitative methods, with minimal operator dependency, would be useful for clinical and research applications. Myocardial perfusion reserve (MPR), calculated using Fermi deconvolution technique, has been compared with well established anatomical and physiological CAD detection techniques. MPR appears to be the most accurate quantitative index to detect anatomical and hemodynamically significant CAD. Beyond physiological assessment of CAD, cMRI provides information regarding regional and global left ventricular function and morphology, myocardial infarction size, transmurality and viability. Such comprehensive information would require the performance of multiple tests if other modalities were used. This article describes current applications of cMRI for evaluation of patients with CAD.

Saphenous vein graft disease.

Saphenous vein graft (SVG) disease has been an obstinate problem facing the cardiologist since the early days of coronary artery bypass grafting (CABG) surgery. SVG disease follows temporally distinct phases of thrombosis, intimal hyperplasia and progressive atherosclerosis leading to recurrent ischemia which can be treated with repeat operation or percutaneous revascularization. However, repeat operation is associated with high mortality and morbidity. Also, percutaneous treatment of SVG disease is complicated by a high rate of procedural and long term complications due to the interrelated phenomena of distal embolization, slow flow or no reflow, periprocedure myocardial infarction, and subsequent restenosis. Long-term patency is poor in this patient population regardless of the treatment modality. Many pharmaceutical and device based approaches have been tested to avert these complications, but few, such as the use of distal protection devices, have shown benefit. The novel drug-eluting stents show promise in reducing the occurrence of restenosis and solving one of the problems associated with the percutaneous treatment of SVG disease. The pathogenesis and therapeutic options for SVG disease is reviewed in this article.

Shoot production per responsive leaf explant increases exponentially with explant organogenic potential in Nicotiana species.

As part of the effort to develop optimal plant varieties for the production and molecular farming of plant-made pharmaceuticals, this study evaluated shoot organogenic potential of a total of 115 Nicotiana accessions, representing 53 species. To induce shoots, leaves from seedling grown in vitro were cut into pieces, cultured on shoot-induction medium under low light for 3 weeks, and then subcultured onto the same medium for another 4 weeks under normal light. Statistical analysis detected significant differences among the 115 accessions for the percentage of leaf explants producing shoots and the number of shoots produced per responsive leaf explant. Importantly, regression analysis also found an exponential relationship between the number of shoots produced per responsive leaf explant and the percentage of leaf explants producing shoots. The number of shoots produced per responsive leaf explant increased rather slowly, ranging from zero to around five, as the percentage of leaf explants producing shoots increased from 0 to 80%, but the increase became dramatic as the percentage increased from 80% to 100%, reaching as high as 35 shoots per responsive leaf explant. This exponential relationship is the first of its kind to be established in plant regeneration studies using either organogenesis or somatic embryogenesis systems. A possible mechanism that governs the establishment of the exponential relationship is discussed.

Traumatic head injury in the anticoagulated elderly patient: a lethal combination.

Warfarin is the most common oral anticoagulant used for chronic anticoagulation therapy. Even without any antecedent trauma overanticoagulation can result in intracranial hemorrhage. The triad of anticoagulation with warfarin, age greater than 65 years, and traumatic head injury frequently produces a lethal brain hemorrhage. A retrospective review of more than 2000 patients admitted to the Trauma Service between September 1998 and May 2000 produced 278 patients with head injury and CT-documented intracranial hemorrhage. Of these patients 21 were admitted with an elevated prothrombin time (PT) due to anticoagulation with warfarin. Eighteen patients (86%) were above the age of 70. The most common indications for anticoagulation were atrial fibrillation (71%), deep venous thrombosis (19%), aortic valve replacement (9%), and ischemic cerebral infarcts (9%). Fourteen injuries were the result of a fall, one resulted from a gunshot wound, and one resulted from an assault. The remaining five patients were excluded as their history, workup, and evaluation by neurosurgery suggested a spontaneous bleed leading to fall rather than a fall causing a traumatic bleed. The average Glasgow Coma Score on admission was 11. The average PT and International Normalized Ratio (INR) on admission were 19.2 and 2.99 respectively. Eight of the 16 patients analyzed died. The risk of intracranial hemorrhage with relatively minor head injury is increased dramatically in the anticoagulated patient. A mortality rate of 50 per cent far exceeds the mortality rate in patients with similar head injuries who are not anticoagulated. In addition the risk/benefit equation of anticoagulation for the elderly is more complex and differs from that for younger patients. Perhaps more frequent and judicious monitoring of prothrombin time levels with lower therapeutic ranges (INR 1.5-2) is necessary.

Discrimination of spatial relations and features in faces: effects of inversion and viewing duration.

We studied discrimination of changes in eye position, mouth position, and eye colour at viewing durations ranging from 1 second to unlimited time. With upright faces, perception was rapid and did not improve above 2 seconds viewing time. Face inversion impaired discrimination of mouth position significantly, eye position slightly, but not eye colour. The 'inversion effect' for mouth position decreased with increasing stimulus duration, and disappeared when the subject knew that the only change in a trial was in mouth position. A subsequent experiment showed that the inversion impairment in the mouth region was not specific to spatial position but affected mouth colour to a lesser degree. When the mouth region was made more salient by increasing the frequency of mouth change trials, the inversion effect for mouth position decreased, and correlated with an increase in inversion effect for eye position but not eye colour. We conclude that the dominant effect of face inversion upon perception is decreased discrimination in less salient facial regions, that this impairment lessens with increasing viewing time, and that it affects both features and their spatial relations, though the effect on the latter is greater. These results are consistent with greater dependence on a serial component search strategy in inverted faces.

Blunt innominate artery injury.

Traumatic injury to the innominate artery is a rare occurrence. A literature review reveals that penetrating wounds account for the overwhelming majority of these injuries. Fewer than 90 cases of innominate artery injury caused by blunt trauma have been documented. Over the past 12 months the trauma service successfully treated two patients with blunt injury to the innominate artery. Both cases involved high-speed motor vehicle crashes with sudden deceleration. Both patients were wearing lap and shoulder restraints and had similar associated bruising following the line of the shoulder harness. The first patient presented with a wide mediastinum on chest X-ray. Angiography revealed an innominate artery injury at the aortic arch. The second patient had a normal chest X-ray. Given the extent of soft tissue bruising from the shoulder harness he underwent a magnetic resonance angiography, which was suspicious for an innominate artery injury. Arch aortography confirmed a disruption of the innominate artery midway between its origin and its bifurcation. Both were repaired through a median sternotomy with cervical extension as necessary. Given the present technology of safety restraint devices this injury may occur with greater frequency. A "shoulder strap sign" should prompt a search for more extensive injuries.

The QUinapril Ischemic Event Trial (QUIET): evaluation of chronic ACE inhibitor therapy in patients with ischemic heart disease and preserved left ventricular function.

Angiotensin-converting enzyme inhibitors improve endothelial function, inhibit experimental atherogenesis, and decrease ischemic events. The Quinapril Ischemic Event Trial was designed to test the hypothesis that quinapril 20 mg/day would reduce ischemic events (the occurrence of cardiac death, resuscitated cardiac arrest, nonfatal myocardial infarction, coronary artery bypass grafting, coronary angioplasty, or hospitalization for angina pectoris) and the angiographic progression of coronary artery disease in patients without systolic left ventricular dysfunction. A total of 1,750 patients were randomized to quinapril 20 mg/day or placebo and followed a mean of 27 +/- 0.3 months. The 38% incidence of ischemic events was similar for both groups (RR 1.04; 95% confidence interval 0.89 to 1.22; p = 0.6). There was also no significant difference in the incidence of patients having angiographic progression of coronary disease (p = 0.71). The rate of development of new coronary lesions was also similar in both groups (p = 0.35). However, there was a difference in the incidence of angioplasty for new (previously unintervened) vessels (p = 0.018). Quinapril was well tolerated in patients after angioplasty with normal left ventricular function. Quinapril 20 mg did not significantly affect the overall frequency of clinical outcomes or the progression of coronary atherosclerosis. However, the absence of the demonstrable effect of quinapril may be due to several limitations in study design.

Results of the study to determine rotablator and transluminal angioplasty strategy (STRATAS).

Rotational atherectomy is used to debulk calcified or complex coronary stenoses. Whether aggressive burr sizing with minimal balloon dilation (<1 atm) to limit deep wall arterial injury improves results is unknown. Patients being considered for elective rotational atherectomy were randomized to either an "aggressive" strategy (n = 249) (maximum burr/artery >0.70 alone, or with adjunctive balloon inflation < or = 1 atm), or a "routine" strategy (n = 248) (maximum burr/artery < or =0.70 and routine balloon inflation > or =4 atm). Patient age was 62 +/- 11 years. Fifty-nine percent routine and 60% aggressive strategy patients had class III to IV angina. Fifteen percent routine and 16% aggressive strategy patients had a restenotic lesion treated; lesion length was 13.6 versus 13.7 mm. Reference vessel diameter was 2.64 mm. Maximum burr size (1.8 vs 2.1 mm), burr/artery ratio (0.71 vs 0.82), and number of burrs used (1.9 vs 2.7) were greater for the aggressive strategy, p <0.0001. Final minimum lumen diameter and residual stenosis were 1.97 mm and 26% for the routine strategy versus 1.95 mm and 27% for the aggressive strategy. Clinical success was 93.5% for the routine strategy and 93.9% for the aggressive strategy. Creatine kinase-myocardial band (CK-MB) was >5 times normal in 7% of the routine versus 11% of the aggressive group. CK-MB elevation was associated with a decrease in rpm of >5,000 from baseline for a cumulative time >5 seconds, p = 0.002. At 6 months, 22% of the routine patients versus 31% of the aggressive strategy patients had target lesion revascularization. Angiographic follow-up (77%) showed minimum lumen diameter to be 1.26 mm in the routine group versus 1.16 mm in the aggressive group, and the loss index 0.54 versus 0.62. Dichotomous restenosis was 52% for the routine strategy versus 58% for the aggressive strategy. Multivariable analysis indicated that left anterior descending location (odds ratio 1.67, p = 0.02) and operator-reported excessive speed decrease >5,000 rpm (odds ratio 1.74, p = 0.01) were significantly associated with restenosis. Thus, the aggressive rotational atherectomy strategy offers no advantage over more routine burr sizing plus routine angioplasty. Operator technique reflected by an rpm decrease of >5,000 from baseline is associated with CK-MB elevation and restenosis.

Intermodal blocking in honeybees.

Previous findings of intramodal but not of intermodal blocking in foraging honeybees prompted a new series of experiments with colours, odours, a proximal visual landmark, and a localized geomagnetic anomaly as stimuli. In Experiments 1-2, the landmark was blocked by both colour and odour. In Experiments 3-6, the anomaly was blocked by both colour and odour, but the anomaly failed to block either colour or odour. In Experiments 7-8, the anomaly failed again to block either colour or odour even though it could be shown to develop substantial associative strength in the course of the training. The several instances of intermodal blocking bring the results for honeybees into closer agreement than before with the results for vertebrates. The failures of blocking seem understandable in terms of the relative salience of the stimuli employed without reference to modal relationships. An attentional interpretation is suggested.

Traumatic adult respiratory distress syndrome.

ARDS is the pulmonary manifestation of both direct and indirect insults to the lung. Trauma patients are at particular risk for ARDS from the direct effects of their injuries, as well as from complications that may occur during their hospital courses. ARDS prevention can be enhanced through diverse areas of medical focus. Public health issues addressing trauma prevention, improved understanding and treatment of trauma-related pathophysiology, as well as a better understanding of basic pathophysiology of this disease process will allow refinement and improvement of our management practices. Newer modes of mechanical ventilation may help us to avoid ventilator-induced exacerbation of lung injury. As we define the role of nonconventional therapies, such as anti-inflammatory and anticytokine therapies, our ability to actively interrupt and reverse the progression of the inflammatory cascade will be enhanced. As yet, ARDS continues to be a challenging disease process to both fully understand and successfully treat in our critically ill patients.

Standard versus low-dose weight-adjusted heparin in patients treated with the platelet glycoprotein IIb/IIIa receptor antibody fragment abciximab (c7E3 Fab) during percutaneous coronary revascularization. PROLOG Investigators.

Blockade of the platelet glycoprotein IIb/IIIa receptor by abciximab (c7E3 Fab) during coronary intervention reduces the incidence of ischemic complications, but has been associated with a doubling of the risk for bleeding complications. The present pilot study investigated whether modification of heparin dosing and/or early sheath removal would reduce the hemorrhagic complications associated with abciximab. One hundred three patients undergoing coronary intervention received abciximab (0.25 mg/kg bolus, 10 microg/min infusion for 12 hours) and aspirin and were randomized by a 2 x 2 factorial design to 1 of 2 weight-adjusted heparin doses and to 1 of 2 strategies for heparin discontinuation and vascular sheath removal. In the "standard-dose heparin" group, an initial bolus of 100 U/kg was administered to achieve a procedural activated clotting time (ACT) > or = 300 seconds; in the "low-dose heparin" group, an initial bolus of 70 U/kg was administered without adjustment for ACT. In the "late sheath removal" arm, heparin infusion was continued for the 12-hour duration of abciximab infusion, followed by sheath removal; in the "early sheath removal" group, heparin was stopped after the interventional procedure and sheaths were removed during the abciximab infusion. There were no apparent differences between patients randomized to the different treatment groups with regard to the occurrence of ischemic end points. Rates of bleeding and blood transfusion were reduced by low-dose heparin and early sheath removal and were lowest when both strategies were combined. Reduction and weight adjustment of heparin dose and early sheath removal in the setting of platelet inhibition with abciximab during coronary intervention may be useful in diminishing the incidence of hemorrhagic complications without loss of clinical efficacy.

Familial recurrence of pulmonary sequestration.

BACKGROUND: Pulmonary sequestration is not believed to be familial. We report two male infants with this anomaly who were born to the same parents. CASES: The prenatal diagnosis of pulmonary sequestration was made in a woman's two consecutive pregnancies by demonstrating systemic arterial supply to an echogenic mass located in the left lower lung of each fetus. Postnatal radiographic evaluation confirmed the prenatal diagnoses. CONCLUSION: Recurrent pulmonary sequestration in two male offspring from the same parents raises the possibility of a genetic predisposition for this condition.

Coronary thrombi increase PTCA risk. Angioscopy as a clinical tool.

BACKGROUND: The presence of angiographically identified intracoronary thrombus has been variably associated with complications after coronary angioplasty. Angiography has been shown to be less sensitive than angioscopy for detecting subtle details of intracoronary morphology, such as intracoronary thrombi. The clinical importance of thrombi detectable by angioscopy but not by angiography is not known. METHODS AND RESULTS: Percutaneous coronary angioscopy was performed in 122 patients undergoing conventional coronary balloon angioplasty (PTCA) at six medical centers. Unstable angina was present in 95 patients (78%) and stable angina in 27 (22%). Therapy was not guided by angioscopic findings, and no patient received thrombolytic therapy as an adjunct to angioplasty. Coronary thrombi were identified in 74 target lesions (61%) by angioscopy versus only 24 (20%) by angiography. A major in-hospital complication (death, myocardial infarction, or emergency bypass surgery) occurred in 10 of 74 patients (14%) with angioscopic intracoronary thrombus, compared with only 1 of 48 patients (2%) without thrombi (P = .03). In-hospital recurrent ischemia (recurrent angina, repeat PTCA, or abrupt occlusion) occurred in 19 of 74 patients (26%) with angioscopic intracoronary thrombi versus only 5 of 48 (10%) without thrombi (P = .03). Relative risk analysis demonstrated that angioscopic thrombus was strongly associated with adverse outcomes (either a major complication or a recurrent ischemic event) after PTCA (relative risk, 3.11; 95% CI, 1.28 to 7.60; P = .01) and that angiographic thrombi were not associated with these complications (relative risk, 0.85; 95% CI, 0.36 to 2.00; P = .91). CONCLUSIONS: The presence of intracoronary thrombus associated with coronary stenoses is significantly underestimated by angiography. Angioscopic intracoronary thrombi, the majority of which were not detected by angiography, are associated with an increased incidence of adverse outcomes after coronary angioplasty.