OP0094 PULMONARY ARTERIAL HYPERTENSION IN ADULT-ONSET STILL’S DISEASE: A CASE SERIES OF 13 PATIENTS

Background:

Pulmonary Arterial Hypertension (PAH) is a rare but potentially fatal complication of Adult-Onset Still’s Disease (AOSD) (1). To date, only isolated observations have been published.

Objectives:

To establish the largest case series of AOSD patients with PAH, and to describe their clinical profile, evolution and response to treatments.

Methods:

Cases were retrospectively identified from the French PAH network database and from an online call of the “Club Rhumatismes et Inflammation” (http://www.cri-net.com). To be included, all patients had to fulfil the Yamaguchi or Fautrel’s criteria for AOSD and PAH had to be confirmed by right heart catheterization. The data were collected using a standardized questionnaire.

Results:

Thirteen patients were identified. All were female, the mean age at PAH diagnosis was 32± 12 years, 2 (15%) patients were Caucasian, 6 (46%) from Sub-Saharan Africa, 1 (8%) from Asia and 4 (31%) from West Indies. Only 2 (15%) patients were smokers. All patients had a systemic onset of AOSD, 12 had a polycyclic and 1 a chronic articular evolution, and the mean delay between AOSD and PAH diagnosis was 2.9 (range 1.7 -5.4) years. At PAH diagnosis, patients were receiving the following treatments: 13 (100%) corticosteroids (median dose 12 mg [interquartile range (IQR) 9-18]), 3 (23%) methotrexate, 8 (61%) interleukin (IL)-1 inhibitors (exposure median duration 6.7 months [IQR 3.6-8.5]), none IL-6 inhibitors, 2 (15%) TNF inhibitors. Six (46%) patients developed PAH during an AOSD flare. PAH was severe at diagnosis: 2 (15%), 7 (54%) and 4 (31%) patients were in NYHA functional class II, III and IV, respectively, with a median 6-minute walk distance of 289 m [IQR 0-448], a mean pulmonary arterial pressure of 41 ± 12 mmHg, a mean pulmonary arterial occlusion pressure of 6 ± 3 mmHg, a mean cardiac output of 3.9 ± 1.2 L/min, a mean cardiac index of 2.5 ± 0.9 L/min/m2 and a median pulmonary vascular resistance of 7 Wood Units [IQR 6-11]. The treatment prescribed after PAH diagnosis is detailed in the table. The median follow-up was 34 months [IQR 7-42]. Five patients (38.5 %) died. Figure 1 shows the overall survival. The haemodynamic response to PAH treatment seemed to be dissociated from the prognosis since several patients have died while their haemodynamic had improved or almost normalised.

Conclusion:

PAH is a rare but potentially severe complication of AOSD, leading to death in 38.5% of our cases series. AOSD remission should be physicians’ objective, since PAH seems to occur when the underlying disease is not controlled.

References:

[1]Feist E, Mitrovic S, Fautrel B. Mechanisms, biomarkers and targets for adult-onset Still’s disease. Nat Rev Rheumatol. 2018;1:603-618.

Table 1.

Therapeutic management

Treatmentn (%)Inotropic therapy5 (38%)HTAP treatment10 (77%)•0Monotherapy3•oInitial oral dual combination therapy3•nDual combination therapy including intravenous (IV) prostacyclin1•uUpfront triple combination therapy including IV prostacyclin3High-dose corticosteroids9 (69%)Interleukin 1 inhibitors initiation2 (15%)Interleukin 6 inhibitors initiation5 (38%)

Acknowledgements:

The authors want to thank the Club Rhumatismes et Inflammation for the diffusion of the online call.

Disclosure of Interests:

None declared

POS0274-HPR BARRIERS TO PHYSICAL ACTIVITY COLLECTED BY THE IFAB QUESTIONNAIRE CORRELATE WITH LEVELS OF PHYSICAL ACTIVITY IN PATIENTS WITH RHEUMATOID ARTHRITIS OR SPONDYLOARTHRITIS: A CROSS-SECTIONAL STUDY OF 150 PATIENTS

Background:

Physical activity is important for patients with inflammatory arthritis (IA), such as spondyloarthritis (axSpA), rheumatoid arthritis (RA) or psoriatic arthritis (PsA). They are more prone to physical inactivity but derive specific benefits from regular physical activity (1,2). It is not easy to modify physical activity level (3). Barriers and facilitators to physical activity can be assessed through questionnaires (4), however, it is important to demonstrate a link between these explanatory elements and physical activity levels.

Objectives:

To measure the correlation between barriers and facilitators to physical activity, assessed through a simple questionnaire, and self-reported physical activity levels.

Methods:

This was an international, multicentric, cross-sectional study performed between October 2019 and June 2020 (ClinicalTrial NCT04426747). Consecutive patients were included if they had definite axSpA, RA or PsA, were aged above 18 and able to walk. Barriers and facilitators to physical activity were measured using the 10-item Inflammatory arthritis Facilitators and barriers questionnaire (IFAB) (5). The IFAB ranges -70 to 70 with lower scores indicating more barriers; scores below -5 correspond to significant barriers. Physical activity was measured by the IPAQ-S questionnaire (6). Exploratory analyses used steps per day collected by smartphone, and psychological readiness to change by stages of behavior change. Statistical analysis used Spearman correlation (rho, p<0.05), Student T test or multivariate analysis using R version 3.5.1. There was no imputation of missing data.

Results:

Of 245 patients included, 150 had analysable data (69 (46%) axSpA, 63 (42%) RA, 18 (12%) PsA). Mean age was 48.6 years (SD 17.1), mean disease duration 11.7 (10.1) years and 60% were women. The mean score of barriers and facilitators to physical activity was 6.0 (SD 19.2, median 4) (Figure 1). A total of 39 (26%) patients scored less than -5, which could justify a targeted intervention. The mean physical activity was 2837 (SD 2668, median 1784) Metabolic Equivalent of Task min per week. Physical activity was correlated with score of barriers and facilitators to physical activity in linear regression (rho 0.28, p<0.001), as well as the stage of behavior change regarding active lifestyle (rho 0.35, p<0.001). No correlation was observed with steps per day (Table 1)

Table 1

for abstract: correlation between IFAB questionnaire, each items and level of physical activity with or without extreme values

ItemCorrelation with IPAQ-S min/met/week, rhoCorrelation with stage of behavior change, rhoCorrelation with mean steps per day, rhoTotal IFAB score0.28 ***0.35 ***0.08Item 10.29 ***0.16 *0.16 *Item 20.060.020.05Item 30.080.16 *0.01Item 40.130.09-0.07Item 5-0.090.100.07Item 60.22 **0.25 ***-0.05Item 70.22 **0.20 **0.12Item 80.16 *0.26 ***0.11Item 90.150.33 ***0.11Item 100.090.17 *0.02Social support questions0.140.27 ***-0.03Psychological and knowledge status questions0.22 **0.16 *0.09

*=P<0.05, **=p<0.01, ***=p<0.001

Conclusion:

Perceived barriers and facilitators to physical activity are correlated with physical activity. Targeting patients with high barriers and low facilitators to physical activity could be an effective option to improve physical activity levels.

References:

[1]O’DWYER T., et al. Rheumatology 2014. Vol. 53, n° 10, pp. 1812-1817.

[2]OSTHOFF, A et al. 2018. Vol. 77, n° 9, pp. 1251-1260. DOI 10.1136/annrheumdis-2018-213585.

[3]MARLEY, J, et al: BMC Musculoskeletal Disorders. 2017. Vol. 18, pp. 482. DOI 10.1186/s12891-017-1836-2.

[4]COSTE, N., et al. 2019. DOI 10.1016/j.rehab.2019.07.009.

[5]DAVERGNE, T, et al. Rheumatology International 2020. DOI 10.1007/s00296-020-04692-4.

[6]LEE, PH, et al. 2011. Vol. 8, pp. 115. DOI 10.1186/1479-5868-8-115.

Figure 1.

Distribution of the IFAB score Footnote: Y axis: effectifs, X axis: IFAB score (possibles values from -70 to 70)

Acknowledgements:

I have no acknowledgements to declare.We thank the following coinvestigators: Sylvie Rozenberg, Beatrice Banneville, Rachida Inaoui, Emmanuelle Dernis, Athan Baillet and Catherine Beauvais, and we thank Hervé Servy for expert CRO advice

Disclosure of Interests:

None declared

AB0772 JAK INHIBITORS IN REFRACTORY ADULT AND CHILDHOOD ONSET STILL’S DISEASE

Background:

Excessive and inappropriate production of pro-inflammatory cytokines such as interleukin (IL)-1, IL-6 or IL-18, is a pathogenic cornerstone in adult and childhood onset Still’s disease. Beyond therapies targeting IL-1 or IL-6, Janus kinases (JAK) inhibitors have been proposed for adult-onset Still’s disease (AOSD) patients refractory to or intolerant of treatment with biologicals. Recently, it has been suggested that JAK inhibitors might be efficient in refractory AOSD patients1.

Objectives:

To assess the efficacy and safety of JAK inhibitors in the treatment of refractory systemic juvenile idiopathic arthritis (sJIA) or AOSD.

Methods:

This retrospective study was based on a national survey of the departments of rheumatology, paediatric rheumatology and internal medicine in all French hospitals from an online call of the “Club Rhumatismes et Inflammation” (www.cri-net.com). The data were collected using a standardized questionnaire, and analyzed at different time points (treatment initiation, M1, M3, M6 and end of the follow-up). The response to JAK inhibitors was categorized as: complete remission (resolution of all clinical and biologic signs), partial remission (clinical improvement with persistence of a few symptoms) or failure (lack of clinical or biological improvement).

Results:

6 patients (5 adults and 1 child) were recruited (Table 1). Mean age at treatment start was 39.6 years for the AOSD patient and 6 years for the sJIA patient, and mean disease duration was 5.3 years. The clinical expression was predominantly systemic in 5 five patients and chronic articular in one. Response to corticosteroids, conventional synthetic or biological Disease Modifying Anti-Rheumatic Drugs had been considered inadequate in all patients. Baricitinib was used in 3 patients, ruxolitinib in 2, and tofacitinib in 1. Steroids were concurrently used in all patients, anakinra in one, methotrexate and anakinra in one. At a mean (SD) follow-up of 9.5 months, partial response was observed in 4 (66.7%) cases (patients with ruxolitinib, tofacitinib or baricitinib) and failure in 2 (33.3%) (patients with baricitinib). No patient achieved complete remission. At the last visit, steroids could be decreased but not stopped in all patients. Patients with partial response had an average decrease of 72,8% (90% for tofacitinib, 70% for baricitinib, 58.5% for ruxolitinib between the start and the follow-up end date) and non-responder patients were yet able to reduce steroids by 60,5% (Table 1). Tolerance of JAK inhibitors was excellent, however patient 4 experienced an episode of infectious pulmonary disease.

Conclusion:

JAK inhibitors therapy may be helpful for some patients with refractory Still’s disease. However, no complete response was observed in this short series of cases. There might be a difference of response between the molecules, although the number of patients is too low to draw conclusions. Additional information is thus needed to evaluate more precisely the risk-benefit ratio of this treatment, and a possible difference in efficacy among the different groups of JAK inhibitors.

References:

[1]Hu Q, Wang M, Jia J, et al. Ann Rheum Dis 2020;0:1–3. doi:10.1136/annrheumdis-2019-216

Table 1.

Characteristics of the AOSD patient

No.SexAge (year)Main symptomsTreatments before JAKi onsetJAK inhibitorsSteroids at onset (mg/day)Concomitant treatmentResponse at last F-USteroids at the end of F-U (mg/day)F-U (months)1F6Fever, polyarthritis, rashAINS, ANAKI, TOCI, CANAKI, ADA, THALI, INFLIXRUXOLITINIB 5mgx2/day30P1232M28Fever, polyarthritis, rashANAKIBARICITINIB 4mg/day800N1013M32Fever, polyarthritis, rashTOCI+MTX, ANAKI+MTX, CANAKI+MTX, ADA, CICLO, IgIVBARICITINIB 4mg/day16MTX 20 mg/week ANAKINRA 100mg/dayP12194F40Fever, polyarthritis, rashMTX, IMUREL, CICLO, ETANERCEPT, ANAKI+MTX, TOCI+MTX, IgIVRUXOLITINIB 15mgx2/day60ANAKI 200mg/dayP3045F48Fever, polyarthritis, rashTOCI, ANAKI, CICLO, CANAKI, IMURELTOFACITINIB 5mgx2/day500P7.596F50Fever, polyarthralgia, rashANAKIBARICITINIB 4mg/day600N401

F-U: Follow-up

N: No response

P: Partial response

Acknowledgements:

I thank all the coauthors, particularly Stéphane Mitrovic and Bruno Fautrel. Also, a special thank to the CRI.

Disclosure of Interests:

None declared

P561Acute effects of dronedarone and amiodarone on functional, morphological and oxidative stress parameters in isolated rat heart with hypertension

Introduction

Amiodarone represents the most widely used antiarrhythmic drug, even though it has been shown that it has negative inotropic and lusitropic effect in healthy hears. On the other hand, dronedarone reduces the risk of recurrent atrial fibrillation, but with increased early mortality related to the worsening of heart failure. However, the mechanisms responsible for these fatal outcomes remain unclear and require further examinations. 

Purpose

To investigate acute, direct effects of Dronedarone and Amiodarone on cardiac contractility, coronary flow and oxidative stress parameters in isolated rat heart with hypertension.

Methods

 The present study was carried out on 18 isolated hearts of spontaneously hypertensive Wistar Kyoto male rats (6 weeks old, bodyweight 200 ± 10 g). After isolation, all hearts were retrogradely perfused according to Langendorff technique with a gradually increment of coronary perfusion pressure (CPP from 40 to 120 cm H2O) and randomly divided into 3 groups: Control (n = 6), Amiodarone (n = 6, isolated hearts perfused with Amiodarone in dose of 3 umol), Dronedarone (n = 6, isolated hearts perfused with Dronedarone in dose of 1.8 umol). During ex vivo protocol continuously were registered cardiac contractility parameters and coronary flow, while from collected coronary venous effluent markers of oxidative stress were measured. All hearts were then fixated and stained with Hematoxylin/eosin.

Results

 Dronedarone severely depressed the function of all cardiodynamic parameters of the heart compared with Amiodarone or Control while Amiodarone intensified the function of the isolated rat heart with hypertension compared to Control (dp/dt max mmHg/s at coronary perfusion pressure 120cmH2O Dronedarone vs. Amiodarone vs. Control 579.733 ± 202.27 vs. 3063.65 ± 467.93 vs. 2682.88 ± 368.75; p &lt; 0.001. dp/dt min mmHg/s 120cmH2O -352.13 ± 204.65 vs. 1960 ± 242.21 vs. -1858.83 ± 118.23; p &lt; 0.001. SLVP mmHg at CPP 120cmH20 27.8 ± 3.46 vs. 98.95 ± 11.78 vs. 71.45 ± 7.56; p &lt; 0.001. DLVP mmHg at CPP 120cmH2O 6.32 ± 0.49 vs. 4.83 ± 0.54 vs. 0.85 ± 0.35; p &lt; 0.001). Acute administration of Dronedarone decreased the level of NO2- and increased the level of H2O2 , while Amiodarone heightens O2- levels (O2- nmol/min g wt at coronary perfusion pressure 120cmH2O Dronedarone vs. Amiodarone vs. Control  28.62 ± 2.54 vs. 77.3 ± 8.86 vs. 31.72 ± 4.56; p &lt; 0.001. H2O2 nmol/min g wt at CPP 120cmH2O 92.56 ± 11.65 vs. 48.63 ± 10.11 vs. 42.84 ± 84; p &lt; 0.001. NO2- nmol/min g wt at CPP 120cmH2O 38.61 ± 4.94 vs.  82.28 ± 5.76 vs.  64.71 ± 3.51; p &lt; 0.001). Pathohistological, structural changes were observed in both, experimental groups.

Conclusions

 Acute administration of Dronedarone depresses cardiac function in isolated, working rat heart with hypertension, with decreasing the NO2- levels, increasing the level of H2O2 and enhanced structural changes when compared to Amiodarone.

Making global river ecosystem health assessments objective, quantitative and comparable

Assessing and comparing global river ecosystem health in an objective and quantitative way remains a major challenge. In this study the widely-used semi-quantitative methods Rapid Biological assessment Protocols (RBPs) was used to determine the health of rivers. The findings were then compared to the results derived from our new UAV (Unmanned aerial vehicles) orthophotographic imagery method. This method quantitatively and objectively assesses river ecosystem health. As a comparison, our method was used to quantitatively measure distance and areas of a range of hydrological and biological attributes thus improving the accuracy of distance- and area-related indices, consequently avoiding subjective errors in these estimations that is fraught in methods like the RBPs. To strengthen the objectivity of the assessment the weights of these indices were objectively determined using the entropy weighting method. This new method was then tested using 9551 UAV orthophotographs taken over six field campaigns. It performed satisfactorily, showing that in our study area the health status of mountain rivers was the best with the highest score of 0.94 out of 1.0. Temporally, the health of the river was better in summer (0.65) compared with that in autumn (0.40). Changes in river ecosystem health were driven by variations in biology and water quality. In contrast the outputs of RBPs, especially in relation to distance and area indices, had ~ 20% uncertainty due to visual errors and subjectivity in estimations by observers. The UAV orthophotographic imaging method proposed in this study can improve the ability to compare the health of rivers across different periods and regions throughout the globe.

Cisplatin monotherapy with concurrent radiotherapy versus combination of cisplatin and 5-fluorouracil chemotherapy with concurrent radiotherapy in patients with locoregionally advanced cervical carcinoma

PURPOSE

To compare the efficacy, toxicity and survival of cisplatin monotherapy with concurrent radiotherapy ver-sus combination of cisplatin and 5-fluorouracil (5-FU) with concurrent external beam radiotherapy (EBRT) in patients with locoregionally advanced cervical carcinoma FIGO stages IIB-IV.

METHODS

134 patients with locoregionally advanced, histologically confirmed carcinoma of the uterine cervix were analysed. The first group of patients (n=70; 52.24%) started concomitant chemotherapy on the second day of radiotherapy with single-agent cisplatin 40 mg/m(2) given 2 h before radiotherapy, once a week for 6 courses. The second group of patients (n=64; 47.76%) started concomitant chemotherapy on the second day of radiotherapy with cisplatin 75 mg/m(2). Treatment was continued with 96-h infusion of 5-FU 4 g/m(2) (1 g/ m(2) per day for 5 consecutive days). The patients were irradiated by EBRT followed by intracavitary brachytherapy (ICB).

RESULTS

24- and 42-month survival in the first group were 71.9 and 57.81% and 52.5 and 35.4% in the second group, respectively (p=0.012). Mean time to progression in the first group was 24 months and in second group it was 15.9 months (p=0.012). After 2 years progression was noted in 38.3% of the first and in 62.9% of second group patients (p=0.003). After 40 months 60 patients were without relapse, 35 (57.81%) patients in the first group and 25 (37.147percnt;) patients in the second group (p=0.018).

CONCLUSION

Treatment with combined cisplatin and 5-FU with concurrent EBRT was more efficient in comparison to cisplatin monotherapy with concurrent radiotherapy in patients with locoregionally advanced cervical carcinoma, in terms of 12- and 24-month overall survival and disease relapse after 2 years.

The cost of fall related presentations to the ED: a prospective, in-person, patient-tracking analysis of health resource utilization

We prospectively collected data on elderly fallers to estimate the total cost of a fall requiring an Emergency Department presentation. Using data collected on 102 falls, we found the average cost per fall causing an Emergency Department presentation of $11,408. When hospitalization was required, the average cost per fall was $29,363.

INTRODUCTION

For elderly persons, falls are a major source of mortality, morbidity, and disability. Previous Canadian cost estimates of seniors' falls were based upon administrative data that has been shown to underestimate the incidence of falls. Our objective was to use a labor-intensive, direct observation patient-tracking method to accurately estimate the total cost of falls among seniors who presented to a major urban Emergency Department (ED) in Canada.

METHODS

We prospectively collected data from seniors (>70 years) presenting to the Vancouver General Hospital ED after a fall. We excluded individuals who where cognitively impaired or unable to read/write English. Data were collected on the care provided including physician assessments/consultations, radiology and laboratory tests, ED/hospital time, rehabilitation facility time, and in-hospital procedures. Unit costs of health resources were taken from a fully allocated hospital cost model.

RESULTS

Data were collected on 101 fall-related ED presentations. The most common diagnoses were fractures (n = 33) and lacerations (n = 11). The mean cost of a fall causing ED presentation was $11,408 (SD: $19,655). Thirty-eight fallers had injuries requiring hospital admission with an average total cost of $29,363 (SD: $22,661). Hip fractures cost $39,507 (SD: $17,932). Among the 62 individuals not admitted to the hospital, the average cost of their ED visit was $674 (SD: $429).

CONCLUSIONS

Among the growing population of Canadian seniors, falls have substantial costs. With the cost of a fall-related hospitalization approaching $30,000, there is an increased need for fall prevention programs.

Co-overexpression of bcl-2 and c-myc in uterine cervix carcinomas and premalignant lesions

To establish the role of co-overexpression of bcl-2 and c-myc protooncogenes in uterine cervix carcinogenesis, we examined 138 tissue samples of low grade cervical squamous intraepithelial lesions (SIL), high grade SIL, portio vaginalis uteri (PVU) carcinoma in situ and PVU invasive carcinoma, stage IA-IIA (study group) and 36 samples without SIL or malignancy (control group). The expression of bcl-2 and c-myc was detected immunohistochemically using a monoclonal antibody. Fisher's exact test (P<0.05) was used to assess statistical significance. Overexpression of bcl-2 was found to increase in direct relation to the grade of the cervical lesions. High sensitivity was of great diagnostic significance for the detection of these types of changes in the uterine cervix. On the basis of high predictive values it can be said that in patients with bcl-2 overexpression there is a great possibility that they have premalignant or malignant changes in the uterine cervix. Co-overexpression of bcl-2 and c-myc oncogenes was found only in patients with PVU invasive carcinoma (6/26-23.0%). Statistically significant difference was not found in the frequency of co-overexpression in patients with PVU invasive carcinoma in relation to the control group (Fisher's test; P=0.064). The method's sensitivity of determining these oncogenes with the aim of detecting PVU invasive carcinoma was 23%, while specificity was 72.2%. On the basis of high predictive values (100%), speaking in statistical terms, it can be concluded that all patients with co-overexpression of bcl-2 and c-myc oncogenes will have PVU invasive carcinoma. We confirmed in our research that co-overexpression of bcl-2 and c-myc oncogenes was increased only in PVU invasive carcinoma. However, a more extensive series of samples and additional tests are required to establish the prognostic significance of bcl-2 and c-myc co-overexpression in cervical carcinogenesis.

Abdominal rectus muscle endometriosis after Cesarean section. Extrapelvic localization of endometriosis

INTRODUCTION

Endometriosis is defined by the presence of functional endometrial tissue outside the uterus, where it is normally located. Endometriosis could has intra and extra pelvic localization. Abdominal endometriosis is the most common localization of extrapelvic endometriosis and is usually developed in the connective tissue surrounding the operation. Very rarely this could be found in the muscle tissue. The mechanical transplantation theory is responsible for the development of scar endometriosis.

CASE REPORT

The patient, 35 years old, three years after caesarian section had an operation because of the assumption for the presence of front abdominal hernia, located at the place of previous section. The egg-sized tumor was removed from the abdominal rectus muscle and sent for PH and immunohistochemical analyses. The results showed endometriosis of the muscle with positive estrogen and progesterone receptors. One year after the operation, due to the repeated pains in the scar area, the treatment continued by GNRH analogues and control was performed by serial ultrasound and biochemical markers CA 125.

CONCLUSION

Clinical diagnoses of scar endometriosis could be provided by an accurate anamnesis and physical, ultrasound and biochemical examinations. Scar endometriosis should always be considered when the symptoms are present in cyclic manner, hormone depending, mostly after gynecological operations and worsening during menstruation. The problem was diagnosed by pathohistological analyses (Fig. 4, Ref. 20).

Coupled tomography and distinct-element-method approach to exploring the granular media microstructure in a jamming hourglass

We describe an approach for exploring microscopic properties of granular media that couples x-ray microtomography and distinct-element-method (DEM) simulations through image analysis. We illustrate it via the study of the intriguing phenomenon of instant arching in an hourglass (in our case a cylinder filled with a polydisperse mixture of glass beads that has a small circular shutter in the bottom). X-ray tomography provides three-dimensional snapshots of the microscopic conditions of the system both prior to opening the shutter, and thereafter, once jamming is completed. The process time in between is bridged using DEM simulation, which settles to positions in remarkably good agreement with the x-ray images. Specifically designed image analysis procedures accurately extract the geometrical information, i.e., the positions and sizes of the beads, from the raw x-ray tomographs, and compress the data representation from initially 5 gigabytes to a few tens of kilobytes per tomograph. The scope of the approach is explored through a sensitivity analysis to input data perturbations in both bead sizes and positions. We establish that accuracy of size--much more than position--estimates is critical, thus explaining the difficulty in considering a mixture of beads of different sizes. We further point to limits in the replication ability of granular flows away from equilibrium; i.e., the difficulty of numerically reproducing chaotic motion.

Strain and high temperature superconductivity: unexpected results from direct electronic structure measurements in thin films

Angle-resolved photoemission spectroscopy reveals very surprising strain-induced effects on the electronic band dispersion of epitaxial La(2-x)Sr(x)CuO(4-delta) thin films. In strained films we measure a band that crosses the Fermi level (E(F)) well before the Brillouin zone boundary. This is in contrast to the flat band reported in unstrained single crystals and in our unstrained films, as well as in contrast to the band flattening predicted by band structure calculations for in-plane compressive strain. In spite of the density of states reduction near E(F), the critical temperature increases in strained films with respect to unstrained samples. These results require a radical departure from commonly accepted notions about strain effects on high temperature superconductors, with possible general repercussions on superconductivity theory.

Spectroscopic signatures of a bandwidth-controlled Mott transition at the surface of 1T-TaSe2

High-resolution angle-resolved photoemission data show that a metal-insulator Mott transition occurs at the surface of the quasi-two-dimensional compound 1T-TaSe2. The transition is driven by the narrowing of the Ta 5d band induced by a temperature-dependent modulation of the atomic positions. A dynamical mean-field theory calculation of the spectral function of the half-filled Hubbard model captures the main qualitative feature of the data, namely, the rapid transfer of spectral weight from the observed quasiparticle peak at the Fermi surface to the Hubbard bands, as the correlation gap opens up.

Muscle fiber conduction velocity at different states of isotonic contraction

Conduction velocity (CV), relative twitch force (RTF) and contraction time (CT) of single muscle fibers (SF) and small muscle fiber bundles (FB) were measured at different states of isotonic contraction with double impulse stimuli at varying interstimulus intervals (ISI) from 0 to 1000 ms in the biceps brachii muscle in vivo. During an isotonic contraction, muscle fibers conducted the action potential on average 0.18 m/s faster along the muscle fiber membrane than did relaxed muscle fibers. This difference was statistically significant (P < 0.001). There was a significant positive correlation between the degree of isotonic contraction and fiber bundle conduction velocity (FBCV) with a first peak at the maximum RTF at an ISI of 9 ms and a second peak at the maximum CT at an ISI of 100 ms.

Isolated voluntary facial paresis due to pontine ischemia

We describe a patient with isolated voluntary facial paresis due to a unilateral lacunar lesion in the contralateral mediodorsal middle base of the pons. Transcranial magnetic stimulation confirmed the involvement of supranuclear corticofacial tract fibers and sparing of the corticolingual and corticospinal connections. This observation demonstrates that the fibers conveying voluntary orofacial activation descend mediodorsally at the level of the middle pons and that the fibers conveying emotional activation may be assumed to converge below this level.

Meta-[131I]iodobenzylguanidine in the scintigraphic evaluation of neural crest tumors

Since February 1990, 74 patients (116 studies) underwent scintigraphy with meta-[131I]iodobenzylguanidine ([131I]MIBG). Eighteen patients had pheochromocytomas, 2 paragangliomas, 2 malignant insulinomas, 1 carcinoid, 2 medullary thyroid carcinoma and 49 children had neuroblastomas. Scintigraphy was performed following a thyroid blockade, at 24 and 48 hours after i.v. injection of 0.5 mCi/1.7 m2 [131I]MIBG. Grade of heart intensity (GHI) uptake and the intensity of salivary gland visualization (SGI) were estimated semiquantitatively, according to the method of Nakajo et al. Sensitivity in the primary pheochromocytomas was 93.9%; sensitivity and specificity in the primary neuroblastomas were 93.7% and 100% respectively; in the secondary neuroblastomas they were 100%, and 100%. Metastases in 2 malignant insulinomas and in 1 case of medullary thyroid carcinoma were also demonstrated. Only one false negative (in pheochromocytoma) and one false positive (Conn's syndrome) result was obtained. Mean values and range of MIBG uptake measured according to Shulkin's procedure were: for pheochromocytoma 3.95% (0.1-15), primary neuroblastoma 0.7% (0.05-1.92%), and neuroblastoma metastases 0.12% (0.002-0.83%). Assessment of [131I]MIBG uptake seems to be helpful in the follow-up of some neural crest tumors and is essential as a prelude to [131I]MIBG therapy.