Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Dual-energy x-ray absorptiometry for total-body and regional bone-mineral and soft-tissue composition

Bone mineral density (BMD) and soft-tissue composition of the total body and major subregions were measured with dual-energy x-ray absorptiometry (DEXA). Total body scans were made in 12 young adults (6 male, 6 female) on five occasions at both a medium speed (20 min) and a fast speed (10 min). There were no significant differences in mean results or in precision errors between the two speeds. The precision errors (1 SD) for total body BMD, percent fat in soft tissue (% Fat), fat mass, and lean tissue mass were less than 0.01 g/cm2, 1.4%, 1.0 kg, and 0.8 kg, respectively. These results corresponded to a relative error of 0.8% for total body BMD and 1.5% for lean body mass. Regional BMD and soft-tissue values (arms, legs, trunk) were determined with slightly higher precision errors. Skeletal mineral was 5.8 +/- 0.5% of lean tissue mass (r = 0.96, p less than 0.001). DEXA provides precise composition analysis with a low radiation exposure (less than 0.1 microGy).

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.

Platinum Monolayer on Nonnoble Metal−Noble Metal Core−Shell Nanoparticle Electrocatalysts for O2 Reduction

We synthesized a new class of O2 electrocatalysts with a high activity and very low noble metal content. They consist of Pt monolayers deposited on the surfaces of carbon-supported nonnoble metal-noble metal core-shell nanoparticles. These core-shell nanoparticles were formed by segregating the atoms of the noble metal on to the nanoparticles' surfaces at elevated temperatures. A Pt monolayer was deposited by galvanic displacement of a Cu monolayer deposited at underpotentials. The mass activity of all the three Pt monolayer electrocatalysts investigated, viz., Pt/Au/Ni, Pt/Pd/Co, and Pt/Pt/Co, is more than order of magnitude higher than that of a state-of-the-art commercial Pt/C electrocatalyst. Geometric effects in the Pt monolayer and the effects of PtOH coverage, revealed by electrochemical data, X-ray diffraction, and X-ray absorption spectroscopy data, appear to be the source of the enhanced catalytic activity. Our results demonstrated that high-activity electrocatalysts can be devised that contain only a fractional amount of Pt and a very small amount of another noble metal.

Occurrence, causes, and outcome of delirium in patients with advanced cancer: a prospective study

CONTEXT

Delirium impedes communication and contributes to symptom distress in patients with advanced cancer. There are few prospective data on the reversal of delirium in this population.

OBJECTIVES

To evaluate the occurrence, precipitating factors, and reversibility of delirium in patients with advanced cancer.

DESIGN

Prospective serial assessment in a consecutive cohort of 113 patients with advanced cancer. Precipitating factors were examined using standardized criteria; 104 patients met eligibility criteria.

SETTING

Acute palliative care unit in a university-affiliated teaching hospital.

MAIN OUTCOME MEASURES

Delirium occurrence and reversal rates, duration, and patient survival. Strengths of association of various precipitating factors with reversal were expressed as hazard ratios (HRs) in univariate and multivariate analyses.

RESULTS

On admission, delirium was diagnosed in 44 patients (42%), and of the remaining 60, delirium developed in 27 (45%). Reversal of delirium occurred in 46 (49%) of 94 episodes in 71 patients. Terminal delirium occurred in 46 (88%) of the 52 deaths. In univariate analysis, psychoactive medications, predominantly opioids (HR, 8.85; 95% confidence interval [CI], 2.13-36.74), and dehydration (HR, 2.35; 95% CI, 1.20-4.62) were associated with reversibility. Hypoxic encephalopathy (HR, 0.39; 95% CI, 0.19-0.80) and metabolic factors (HR, 0.44; 95% CI, 0.21-0.91) were associated with nonreversibility. In mulitivariate analysis, psychoactive medications (HR, 6.65; 95% CI, 1.49-29.62), hypoxic encephalopathy (HR, 0.32; 95% CI, 0.15-0.70), and nonrespiratory infection (HR, 0.23; 95% CI, 0.08-0.64) had independent associations. Patients with delirium had poorer survival rates than controls (P<.001).

CONCLUSIONS

Delirium is a frequent, multifactorial complication in advanced cancer. Despite its terminal presentation in most patients, delirium is reversible in approximately 50% of episodes. Delirium precipitated by opioids and other psychoactive medications and dehydration is frequently reversible with change of opioid or dose reduction, discontinuation of unnecessary psychoactive medication, or hydration, respectively.

Double-blind controlled trial of oral clodronate in patients with bone metastases from breast cancer

PURPOSE

Osteolytic metastases often give rise to hypercalcemia, fracture, and bone pain, and occur commonly in patients with recurrent breast cancer. We assessed the bisphosphonate, clodronate, which has proven to be a useful treatment for hypercalcemia and may be a potent inhibitor of tumor-induced osteolysis, for its effect on reducing the osseous complications of metastatic breast cancer.

PATIENTS AND METHODS

We studied 173 patients with bone metastases due to breast cancer in a randomized, double-blind, placebo-controlled trial of oral clodronate 1,600 mg/d (85 patients) compared with an identical placebo (88 patients).

RESULTS

The patients in each wing were comparable in their clinical, radiologic, and biochemical characteristics at trial entry. In patients who received clodronate, there was a significant reduction compared with placebo in the total number of hypercalcemic episodes (28 v 52; P < .01), in the number of terminal hypercalcemic episodes (seven v 17; P < .05), in the incidence of vertebral fractures (84 v 124 per 100 patient-years; P < .025), and in the rate of vertebral deformity (168 v 252 per 100 patient-years; P < .001). The combined rate of all morbid skeletal events was significantly reduced (218.6 v 304.8 per 100 patient-years; P < .001). Trends were seen in favor of clodronate for nonvertebral fracture rates and radiotherapy requirements for bone pain (particularly spinal pain). No significant survival differences and no significant differences in side effects were observed between the two groups.

CONCLUSIONS

These findings indicate that oral clodronate has a beneficial effect on the skeletal morbidity associated with breast cancer and should be considered as antiosteolytic therapy in affected patients. It deserves further investigation as an adjuvant therapy in operable breast cancer and in patients with nonosseous recurrence who are at high risk for bone metastases.

Apolipoprotein E promotes astrocyte colocalization and degradation of deposited amyloid-beta peptides

We have previously shown that apolipoprotein E (Apoe) promotes the formation of amyloid in brain and that astrocyte-specific expression of APOE markedly affects the deposition of amyloid-beta peptides (Abeta) in a mouse model of Alzheimer disease. Given the capacity of astrocytes to degrade Abeta, we investigated the potential role of Apoe in this astrocyte-mediated degradation. In contrast to cultured adult wild-type mouse astrocytes, adult Apoe(-/-) astrocytes do not degrade Abeta present in Abeta plaque-bearing brain sections in vitro. Coincubation with antibodies to either Apoe or Abeta, or with RAP, an antagonist of the low-density lipoprotein receptor family, effectively blocks Abeta degradation by astrocytes. Phase-contrast and confocal microscopy show that Apoe(-/-) astrocytes do not respond to or internalize Abeta deposits to the same extent as do wild-type astrocytes. Thus, Apoe seems to be important in the degradation and clearance of deposited Abeta species by astrocytes, a process that may be impaired in Alzheimer disease.

GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4_{-0.9}^{+0.7}×10^{-22}. The inferred source-frame initial black hole masses are 14.2_{-3.7}^{+8.3}M_{⊙} and 7.5_{-2.3}^{+2.3}M_{⊙}, and the final black hole mass is 20.8_{-1.7}^{+6.1}M_{⊙}. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440_{-190}^{+180}  Mpc corresponding to a redshift of 0.09_{-0.04}^{+0.03}. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2_{-6.0}^{+8.4}M_{⊙} and 19.4_{-5.9}^{+5.3}M_{⊙} (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_{eff}=-0.12_{-0.30}^{+0.21}. This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880_{-390}^{+450}  Mpc corresponding to a redshift of z=0.18_{-0.07}^{+0.08}. We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_{g}≤7.7×10^{-23}  eV/c^{2}. In all cases, we find that GW170104 is consistent with general relativity.

Performance evaluation of a dual-energy x-ray bone densitometer

We tested a dual-energy bone densitometer (LUNAR DPX) that uses a stable x-ray generator and a K-edge filter to achieve the two energy levels. A conventional scintillation detector in pulse-counting mode was used together with a gain stabilizer. The densitometer normally performs spine and femur scans in about 6 minutes and 3 minutes, respectively, with adequate spatial resolution (1.2 x 1.2 mm). Total body scans take either 10 minutes or 20 minutes. The long-term (6 months, n = 195) precision of repeat measurement on an 18-cm thick spine phantom was 0.6% at the medium speed. Precision error in vivo was about 0.6, 0.9 and 1.5% for spine scans (L2-L4) at slow, medium and fast speeds, while the error was 1.2 and 1.5 to 2.0%, respectively, for femur scans at slow and medium speed. The precision of total body bone density was 0.5% in vitro and in vivo. The response to increasing amounts of calcium hydroxyapatite was linear (r = 0.99). The densitometer accurately indicated (within 1%) the actual amount of hydroxyapatite after correction for physiological amounts of marrow fat. The measured area corresponded exactly (within 0.5%) to that of known annuli and to the radiographic area of spine phantoms. There was no significant effect of tissue thickness on mass, area, or areal density (BMD) between 10 and 24 cm of water. The BMD values for both spine and femur in vivo correlated highly (r = 0.98, SEE = .03 g/cm2) with those obtained using conventional 153Gd DPA. Similarly, total body BMD correlated highly (r = 0.96, SEE = .02 g/cm2) with DPA results.

Opioid rotation in patients with cancer pain. A retrospective comparison of dose ratios between methadone, hydromorphone, and morphine

BACKGROUND

When a change of opioid is considered, equianalgesic dose tables are used. These tables generally propose a dose ratio of 5:1 between morphine and hydromorphone. In the case of a change from subcutaneous hydromorphone to methadone, dose ratios ranging from 1:6 to 1:10 are proposed. The purpose of this study was to review the analgesic dose ratios for methadone compared with hydromorphone.

METHODS

In a retrospective study, 48 cases of medication changes from morphine to hydromorphone, and 65 changes between hydromorphone and methadone were identified. the reason for the change, the analgesic dose, and pain intensity were obtained.

RESULTS

The dose ratios between morphine and hydromorphone and vice versa were found to be 5.33 and 0.28, respectively (similar to expected results). However, the hydromorphone/methadone ratio was found to be 1.14:1 (5 to 10 times higher than expected). Although the dose ratios of hydromorphone/morphine and vice versa did not change according to a previous opioid dose, the hydromorphone/methadone ratio correlated with total opioid dose (correlation coefficient = 0.41 P < 0.001) and was 1.6 (range, 0.3-14.4) in patients receiving more than 330 mg of hydromorphone per day prior to the change, versus 0.95 (range, 0.2-12.3) in patients receiving ae330 mg of hydromorphone per day (P = 0.023).

CONCLUSIONS

These results suggest that only partial tolerance develops between methadone and hydromorphone. Methadone is much more potent than previously described and any change should start at a lower equivalent dose.

Effects of adding spironolactone to an angiotensin-converting enzyme inhibitor in chronic congestive heart failure secondary to coronary artery disease

In chronic heart failure, a diuretic plus an angiotensin-converting enzyme (ACE) inhibitor only partially suppresses aldosterone despite the fact that aldosterone has many harmful effects independent of angiotensin II. These possible harmful effects of aldosterone are magnesium loss, increased cardiac sympathetic activity, and increased ventricular arrhythmias. We have therefore assessed whether adding the aldosterone antagonist, spironolactone, to a loop diuretic and ACE inhibitor reverses any of these potentially harmful effects of residual aldosterone. In a preliminary animal study, we found that exogenous aldosterone reduced myocardial norepinephrine uptake by 24% in anesthetized rats in vivo. In our main study, 42 patients with New York Heart Association II to III congestive heart failure were randomized to spironolactone (50 to 100 mg/day, titrated to blood pressure and plasma potassium) or placebo in a double-blind fashion. Our principal finding is that cardiac norepinephrine uptake as assessed by 123I-metaiodobenzylguanidine scintigraphy increased with spironolactone (p < 0.01). Spironolactone also elevated plasma magnesium (p < 0.05), reduced urinary magnesium excretion (p < 0.05), and caused a reduction in ventricular arrhythmias on 24-hour ambulatory electrocardiography (p < 0.05). Spironolactone increased plasma renin activity, plasma aldosterone (p < 0.01), 24-hour urinary sodium excretion (p < 0.05), and urinary sodium/potassium ratio (p < 0.01). Echocardiographic-determined measurements of left ventricular systolic and diastolic function were unaltered by spironolactone.(ABSTRACT TRUNCATED AT 250 WORDS)

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5_{-3.0}^{+5.7}M_{⊙} and 25.3_{-4.2}^{+2.8}M_{⊙} (at the 90% credible level). The luminosity distance of the source is 540_{-210}^{+130}  Mpc, corresponding to a redshift of z=0.11_{-0.04}^{+0.03}. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible region from 1160   deg^{2} using only the two LIGO detectors to 60  deg^{2} using all three detectors. For the first time, we can test the nature of gravitational-wave polarizations from the antenna response of the LIGO-Virgo network, thus enabling a new class of phenomenological tests of gravity.

A prospective multicenter assessment of the Edmonton staging system for cancer pain

Two hundred and seventy-seven patients were admitted to this prospective multicenter study in order to assess the accuracy of a staging system for cancer pain. The staging system (SS) was completed by a trained physician during the initial consultation. This system included the assessment of pain mechanism (PM, neuropathic versus nonneuropathic), pain characteristic (PC, continuous versus incidental), previous opioid dose (OD), cognitive function (CF), psychological distress (PD), tolerance (T), past history of alcohol or drugs (A). During day 21, a final assessment of pain control was made. Agreement for staging was observed in 96% of cases for investigators 1 and 2 (kappa 0.76, P < 0.001), and in 84% of cases between investigators 1 and 3 (kappa 0.723, P < 0.001). Of 276 evaluable patients, 86/92 Stage I (good prognosis) patients achieved good PC (93%) versus 102/184 Stage II and III (poor prognosis) patients (55%, P < 0.001). Sensitivity and specificity of the system were found to be 0.93 and 0.46, respectively. Univariate correlation found significant correlation between pain control and all variables except CF. In logistic regression, CF and OD showed no significant correlation. We, therefore, propose a more simple SS of five categories (PM, PC, PD, T, and A) and two stages (good and poor prognosis). We conclude that the SS is highly accurate in predicting patients with good prognosis, but patients with "poor prognosis" can still achieve good pain control in more than 50% of cases.

The Edmonton staging system for cancer pain: preliminary report

Fifty-six consecutive patients with pain due to cancer were admitted to a prospective study designed to test a clinical staging system for cancer pain. The system classifies patients in stage 1 (good prognosis) to stage 3 (poor prognosis) according to the mechanism of pain, characteristics of pain, previous narcotic exposure, cognitive function, psychological distress, tolerance and past history of drug addiction or alcoholism. During day 1 patients were staged after being seen by one of the investigators. Patients were treated for 21 days, when a final diagnosis of pain control was made. Eighteen of 22 patients in stage 1 achieved good pain control (82%) vs. 2/22 patients in stage 3 (10%; P less than 0.01). Sensitivity, specificity and negative predictive value of the system were 0.75, 0.86 and 0.80, respectively. We conclude that this is a simple and reliable system for clinical staging that can be used for clinical research and management of patients with cancer pain.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Biological Control of Crystal Texture: A Widespread Strategy for Adapting Crystal Properties to Function

Textures of calcite crystals from a variety of mineralized tissues belonging to organisms from four phyla were examined with high-resolution synchrotron x-ray radiation. Significant differences in coherence length and angular spread were observed between taxonomic groups. Crystals from polycrystalline skeletal ensembles were more perfect than those that function as single-crystal elements. Different anisotropic effects on crystal texture were observed for sea urchin and mollusk calcite crystals, whereas none was found for the foraminifer, Patellina, and the control calcite crystals. These results show that the manipulation of crystal texture in different organisms is under biological control and that crystal textures in some tissues are adapted to function. A better understanding of this apparently widespread biological phenomenon may provide new insights for improving synthetic crystal-containing materials.

Tests of General Relativity with GW150914

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 10^{13}  km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.

A comparison of patient and proxy symptom assessments in advanced cancer patients

The purpose of this study was to compare patient and proxy (physician and nurse) assessments of symptoms in advanced cancer patients. The sample consisted of 49 patients with advanced cancer admitted to an acute palliative care unit. Three independent assessments were completed for each patient on two occasions within 11 days of admission. On each occasion, symptoms were rated independently by the patient and two proxies (treating physician and nurse), using the Edmonton Symptom Assessment System (ESAS). The ESAS is a nine-item visual analogue scale (VAS) for assessing pain, activity, nausea, depression, anxiety, drowsiness, appetite, well-being and shortness of breath. Symptom ratings were compared using a repeated-measures ANOVA procedure and correlations. Average physician ratings were generally lower than average patient ratings for both occasions. Average nurse ratings agreed more closely with patient ratings, with a trend towards lower ratings on occasion 1 and higher ratings on occasion 2. There was a significant rater (person rating the effects) effect (P < 0.01) for three of the nine symptoms: physicians rated drowsiness, shortness of breath and pain significantly lower than patients. For drowsiness and shortness of breath, these differences were clinically relevant, representing a difference of more than 12 mm on a 100-mm VAS. The accuracy of assessments amongst those rating the symptoms did not improve over time. Proxy assessments of symptom intensity, particularly by physicians, were significantly lower than patient assessments for three of the nine symptoms. Further research regarding the reliability of patient and proxy assessments is needed to assess and manage symptoms in advanced cancer effectively.

Cognitive failure in patients with terminal cancer: a prospective study

In a prospective open study, 61 consecutive patients with terminal cancer admitted to the hospital underwent cognitive assessment using the Mini-Mental State Questionnaire three times a week between admission and discharge or death. Mini-Mental State Questionnaire score upon admission was 28 +/- 1.5 in patients who were discharged (N = 14), and 25 +/- 3 in patients who died in the hospital (N = 47, P less than 0.01). The forty-seven patients who died in the hospital presented a total of 66 episodes of cognitive failure (CF) that were defined as a score of less than 24 or a drop of greater than 30% in the score on the Mini-Mental State Questionnaire. Of these 47 patients, 39 (83%) presented CF an average of 16 days before death. Upon detection of CF, a complete medical examination, laboratory evaluation, computerized tomography of the brain if indicated by abnormal findings on medical examination, and a complete medication review were performed. The cause of CF could not be established in 37 (56%) cases. Drugs, sepsis, and brain metastasis were the most frequently detected causes and were present in 6, 4, and 4 cases, respectively. In addition, 22 episodes (33%) of CF improved (10 episodes spontaneously and 12 episodes as a result of treatment). Our findings suggest that CF is extremely prevalent during the last weeks of life and, consequently, informed consent for therapeutic or research procedures or resuscitation may be impossible to obtain reliably at that stage.

Direct in vivo assessment of microcirculatory dysfunction in severe falciparum malaria

BACKGROUND

This study sought to describe and quantify microcirculatory changes in the mucosal surfaces of patients with severe malaria, by direct in vivo observation using orthogonal polarization spectral (OPS) imaging.

METHODS

The microcirculation in the rectal mucosa of adult patients with severe malaria was assessed by use of OPS imaging, at admission and then daily. Comparison groups comprised patients with uncomplicated falciparum malaria, patients with bacterial sepsis, and healthy individuals.

RESULTS

Erythrocyte velocities were measured directly in 43 adult patients with severe falciparum malaria, of whom 20 died. Microcirculatory blood flow was markedly disturbed, with heterogeneous obstruction that was proportional to severity of disease. Blocked capillaries were found in 29 patients (67%) and were associated with concurrent hyperdynamic blood flow (erythrocyte velocity, >750 mm/s) in adjacent vessels in 27 patients (93%). The proportion of blocked capillaries correlated with the base deficit in plasma and with the concentration of lactate. Abnormalities disappeared when the patients recovered. In healthy individuals and in patients with uncomplicated malaria or sepsis, no stagnant erythrocytes were detected, and, in patients with sepsis, hyperdynamic blood flow was prominent.

CONCLUSION

Patients with severe falciparum malaria show extensive microvascular obstruction that is proportional to the severity of the disease. This finding underscores the prominent role that microvascular obstruction plays in the pathophysiology of severe malaria and illustrates the fundamental difference between the microvascular pathophysiology of malaria and that of bacterial sepsis.

Effects of oxygen on dyspnoea in hypoxaemic terminal-cancer patients

Dyspnoea is a frequent and devastating symptom of advanced cancer. The purpose of this prospective, double-blind, crossover trial was to assess the effects of supplemental oxygen on the intensity of dyspnoea. 14 patients with hypoxaemic dyspnoea due to advanced cancer were randomised to receive either oxygen or air; the gases were delivered at 5 L/min by mask. After 5 min of stable oxygen saturation (pulse oximetry), patients were crossed over to receive the other treatment. The crossover was repeated twice. Dyspnoea was assessed with a visual analogue scale (O = no dyspnoea, 100 = worst dyspnoea). Mean difference in dyspnoea visual analogue scale between air and oxygen treatment was 20.5 (95% confidence interval 13.5 to 27.6). 12 patients consistently preferred oxygen to air; similarly, the investigator consistently chose oxygen for the same 12 patients. In a global rating questionnaire, patients reported little or no benefit during the air phase compared with moderate to much benefit during the oxygen phase. We conclude that oxygen is beneficial to patients with hypoxia and dyspnoea at rest.

Dosimetric evaluation of lung tumor immobilization using breath hold at deep inspiration

PURPOSE

To examine the dosimetric benefit of self-gated radiotherapy at deep-inspiration breath hold (DIBH) in the treatment of patients with non-small-cell lung cancer (NSCLC). The relative contributions of tumor immobilization at breath hold (BH) and increased lung volume at deep inspiration (DI) in sparing high-dose lung irradiation (> or = 20 Gy) were examined.

METHODS AND MATERIALS

Ten consecutive patients undergoing radiotherapy for Stage I-IIIB NSCLC who met the screening criteria were entered on this study. Patients were instructed to BH at DI without the use of external monitors or breath-holding devices (self-gating). Computed tomography (CT) scans of the thorax were performed during free breathing (FB) and DIBH. Fluoroscopy screened for reproducible tumor position throughout DIBH, and determined the maximum superior-inferior (SI) tumor motion during both FB and DIBH. Margins used to define the planning target volume (PTV) from the clinical target volume included 1 cm for setup error and organ motion, plus an additional SI margin for tumor motion, as determined from fluoroscopy. Three conformal treatment plans were then generated for each patient, one from the FB scan with FB PTV margins, a second from the DIBH scan with FB PTV margins, and a third from the DIBH scan with DIBH PTV margins. The percent of total lung volume receiving > or = 20 Gy (using a prescription dose of 70.9 Gy to isocenter) was determined for each plan.

RESULTS

Self-gating at DIBH was possible for 8 of the 10 patients; 2 patients were excluded, because they were not able to perform a reproducible DIBH. For these 8 patients, the median BH time was 23 (range, 19-52) s. The mean percent of total lung volume receiving > or = 20 Gy under FB conditions (FB scan with FB PTV margins) was 12.8%. With increased lung volume alone (DIBH scan with FB PTV margins), this was reduced to 11.0%, tending toward a significant decrease in lung irradiation over FB (p = 0.086). With both increased lung volume and tumor immobilization (DIBH scan with DIBH PTV margins), the mean percent lung volume receiving > or = 20 Gy was further reduced to 8.8%, a significant decrease in lung irradiation compared to FB (p = 0.011). Furthermore, at DIBH, the additional benefit provided by tumor immobilization (i.e., using DIBH instead of FB PTV margins) was also significant (p = 0.006). The relative contributions of tumor immobilization and increased lung volume toward reducing the percent total lung volume receiving > or = 20 Gy were patient specific; however, all 8 of the patients analyzed showed a dosimetric benefit with this DIBH technique.

CONCLUSION

Compared to FB conditions, at DIBH the mean reduction in percent lung volume receiving > or = 20 Gy was 14.3% with the increase in lung volume alone, 22.1% with tumor immobilization alone, and 32.5% with the combined effect. The dosimetric benefit seen at DIBH was patient specific, and due to both the increased lung volume seen at DI and the PTV margin reduction seen with tumor immobilization.