Ecological lags govern the pace and outcome of plant community responses to 21st-century climate change

Forecasting the trajectories of species assemblages in response to ongoing climate change requires quantifying the time lags in the demographic and ecological processes through which climate impacts species' abundances. Since experimental climate manipulations are typically abrupt, the observed species responses may not match their responses to gradual climate change. We addressed this problem by transplanting alpine grassland turfs to lower elevations, recording species' demographic responses to climate and competition, and using these data to parameterise community dynamics models forced by scenarios of gradual climate change. We found that shifts in community structure following an abrupt climate manipulation were not simply accelerated versions of shifts expected under gradual warming, as the former missed the transient rise of species benefiting from moderate warming. Time lags in demography and species interactions controlled the pace and trajectory of changing species' abundances under simulated 21st-century climate change, and thereby prevented immediate diversity loss.

Lowland plant arrival in alpine ecosystems facilitates a decrease in soil carbon content under experimental climate warming

Climate warming is releasing carbon from soils around the world^1-3, constituting a positive climate feedback. Warming is also causing species to expand their ranges into new ecosystems^4-9. Yet, in most ecosystems, whether range expanding species will amplify or buffer expected soil carbon loss is unknown¹⁰. Here we used two whole-community transplant experiments and a follow-up glasshouse experiment to determine whether the establishment of herbaceous lowland plants in alpine ecosystems influences soil carbon content under warming. We found that warming (transplantation to low elevation) led to a negligible decrease in alpine soil carbon content, but its effects became significant and 52% ± 31% (mean ± 95% CIs) larger after lowland plants were introduced at low density into the ecosystem. We present evidence that decreases in soil carbon content likely occurred via lowland plants increasing rates of root exudation, soil microbial respiration and CO₂ release under warming. Our findings suggest that warming-induced range expansions of herbaceous plants have the potential to alter climate feedbacks from this system, and that plant range expansions among herbaceous communities may be an overlooked mediator of warming effects on carbon dynamics.

How Dispersal Evolution and Local Adaptation Affect the Range Dynamics of Species Lagging Behind Climate Change

AbstractAs climate changes, species' ability to spatially track suitable climate depends on their spread velocity, a function of their population growth and dispersal capacity. When climate changes faster than species can spread, the climate experienced at species' expanding range edges may ameliorate as conditions become increasingly similar to those of the range core. When this boosts species' growth rates, their spread accelerates. Here, we use simulations of a spreading population with an annual life history to explore how climatic amelioration interacts with dispersal evolution and local adaptation to determine the dynamics of spread. We found that depending on the timing of dispersal evolution, spread velocity can show contrasting trajectories, sometimes transiently exceeding the climate velocity before decelerating. Climatic amelioration can also accelerate the spread of populations composed of genotypes best adapted to local climatic conditions, but the exact dynamics depends on the pattern of climatic adaptation. We conclude that failing to account for demographic variation across climatic gradients can lead to erroneous conclusions about species' capacity to spatially track suitable climate.

Phenological plasticity is a poor predictor of subalpine plant population performance following experimental climate change

Phenological shifts, changes in the seasonal timing of life cycle events, are among the best documented responses of species to climate change. However, the consequences of these phenological shifts for population dynamics remain unclear. Population growth could be enhanced if species that advance their phenology benefit from longer growing seasons and gain a pre-emptive advantage in resource competition. However, it might also be reduced if phenological advances increase exposure to stresses, such as herbivores and, in colder climates, harsh abiotic conditions early in the growing season. We exposed subalpine grasslands to ~ 3 K of warming by transplanting intact turfs from 2000 m to 1400 m elevation in the eastern Swiss Alps, with turfs transplanted within the 2000 m site acting as a control. In the first growing season after transplantation, we recorded species' flowering phenology at both elevations. We also measured species' cover change for three consecutive years as a measure of plant performance. We used models to estimate species' phenological plasticity (the response of flowering time to the change in climate) and analysed its relationship with cover changes following climate change. The phenological plasticity of the 18 species in our study varied widely but was unrelated to their changes in cover. Moreover, early- and late-flowering species did not differ in their cover response to warming, nor in the relationship between cover changes and phenological plasticity. These results were replicated in a similar transplant experiment within the same subalpine community, established one year earlier and using larger turfs. We discuss the various ecological processes that can be affected by phenological shifts, and argue why the population-level consequences of these shifts are likely to be species- and context-specific. Our results highlight the importance of testing assumptions about how warming-induced changes in phenotypic traits, like phenology, impact population dynamics.

Effectiveness and persistence of Vedolizumab in patients with inflammatory bowel disease : results from the Belgian REal-LIfe study with VEdolizumab (Be-RELIVE)

BACKGROUND AND STUDY AIMS

Vedolizumab (VDZ) is a gutselective integrin inhibitor used to treat Crohn's disease (CD) and ulcerative colitis (UC). This retrospective study assessed effectiveness and treatment persistence of VDZ in a Belgian reallife cohort of CD and UC patients.

PATIENTS AND METHODS

CD and UC patients from 15 Belgian centers, who started VDZ between 01/09/2015 and 31/06/2016 and attended ≥1 visit after the first VDZ infusion, were included. Data were collected before first infusion, at week (W)10, W14 (CD patients only), month (M)6 and last follow-up. Treatment response and remission rates (changes in disease activity scores) and treatment persistence (Kaplan-Meier analysis) were assessed.

RESULTS

Of the 348 patients receiving at least one dose of VDZ, 325 (202 CD, 45 biologic-naïve; and 123 UC, 42 biologic-naïve) patients were included in data analyses. At M6, 87.6% (176/201) of CD and 86.1% (105/122) of UC patients were still on VDZ treatment, 75.6% (34/45) and 83.9% (26/31) achieved clinical response, and 66.7% (44/66) and 42.9% (15/35) were in remission. At M6 remission rates was significantly higher while response rates tended to be higher among biologic-naïve versus biologic-failure CD patients.

CONCLUSIONS

VDZ offers an effective treatment option in real-life settings and treatment effectiveness appears higher in biologic-naïve versus biologic-failure CD patients. (Acta gastroenterol. belg., 2020, 83, 15-23).

An approach for comparative quantification of myocardial blood flow (0-15-H2O-PET), perfusion (Tc-99m-tetrofosmin-SPECT), and metabolism (F 18-FDG-PET)

Aim: In the present study a new approach has been developed for comparative quantification of absolute myocardial blood flow (MBF), myocardial perfusion, and myocardial metabolism in short-axis slices. Methods: 42 patients with severe CAD, referred for myocardial viability diagnostics, were studied consecutively with 0-15-H2O PET (H2O-PET) (twice), Tc-99m-Tetrofosmin 5PECT (TT-SPECT) and F-18-FDG PET (FDG-PET). All dato sets were reconstructed using attenuation correction and reoriented into short axis slices. Each heart was divided into three representative slices (base, rnidventricular, apex) and 18 ROIs were defined on the FDG PET images and transferred to the corresponding H2O-PET and TT-SPECT slices. TT-SPECT and FDG-PET data were normalized to the ROI showing maximum perfusion. MBF was calculated for all left-ventricular ROIs using a single-compartment-model fitting the dynamic H2O-PET studies. Microsphere equivalent MBF (MBF_micr) was calculated by multiplying MBF and tissue-fraction, a parameter which was obtained by fitting the dynamic H2O-PET studies. To reduce influence of viability only well perfused areas (>70% TT-SPECT) were used for comparative quantification. Results: First and second mean global MBF values were 0.85 ml × min-1 × g-1 and 0.84 ml × min-1 × g1, respectively, with a repeatability coefficient of 0.30 ml ÷ min-1 × gl. After sectorization mean MBF_micr was between 0.58 ml × min1 ÷ ml"1 and 0.68 ml × min-1 × ml"1 in well perfused areas. Corresponding TT-SPECT values ranged from 83 % to 91 %, and FDG-PET values from 91 % to 103%. All procedures yielded higher values for the lateral than the septal regions. Conclusion: Comparative quantification of MBF, MBF_micr, TT-SPECT perfusion and FDG-PET metabolism can be done with the introduced method in short axis slices. The obtained values agree well with experimentally validated values of MBF and MBF_micr.

Characterization of radioiodine therapy failures in Graves’ disease

Aim of this study was a characterization of radioiodine therapy (RIT) failures in Graves’ disease without simultaneous Carbimazole. Method: 226 patients with a confirmed diagnosis of Graves’ disease received 686.8 ± 376.4 MBq of iodine-131 orally for thyroid ablation. Target dose was 250 Gy. All patients were followed up for 6 months. Therapy failures were compared with successes regarding possible influencing variables initial thyroid volume, thyroid function, immune activity (TRAb), 1-131 uptake, effective half-life, absorbed energy dose, age and gender. Results: 212 of 226 patients (93.8%) were treated successfully, 14 (6.2%) showed a hyperthyroidism relapse within 6 months which required a second radioiodine therapy. A success rate of 92.5% (62/67) could also be achieved with 67 patients who were hyperthyroid at the time of RIT. Compared to the therapy successes, the 14 failures achieved significantly lower absorbed doses (223.8 ±76.6 Gyvs. 285.2 ±82.1 Gy, ρ <0.005), but with no significant differences regarding age, thyroid volume, function or TRAb (all ρ >0.2). Of the 14 failures, η = 8 reached an absorbed dose <200 Gy and η = 1 a dose <250 Gy, although 5 of the failures reached an absorbed dose of >250 Gy. Stepwise logistic regression revealed only absorbed energy dose as a variable significantly influencing therapy success (p <0.005), but no influence of initial thyroid volume, function, TRAb value, age (all ρ >0.2) or gender (p = 0.13). Two-tailed Fisher’s exact test showed no significant influence of gender on success rates (failures/successes: male 1 /36, female 13/176, ρ = 0.48). Conclusions: Except for the absorbed energy dose, no other significant variable influencing the outcome of radioiodine therapy in Graves’ disease without simultaneous Carbimazole could be found. It should be noted, though, that 5 therapy failures (2.2%) reached an absorbed energy dose of >250 Gy.

Where to Dig for Fossils: Combining Climate-Envelope, Taphonomy and Discovery Models

Fossils represent invaluable data to reconstruct the past history of life, yet fossil-rich sites are often rare and difficult to find. The traditional fossil-hunting approach focuses on small areas and has not yet taken advantage of modelling techniques commonly used in ecology to account for an organism's past distributions. We propose a new method to assist finding fossils at continental scales based on modelling the past distribution of species, the geological suitability of fossil preservation and the likelihood of fossil discovery in the field, and apply it to several genera of Australian megafauna that went extinct in the Late Quaternary. Our models predicted higher fossil potentials for independent sites than for randomly selected locations (mean Kolmogorov-Smirnov statistic = 0.66). We demonstrate the utility of accounting for the distribution history of fossil taxa when trying to find the most suitable areas to look for fossils. For some genera, the probability of finding fossils based on simple climate-envelope models was higher than the probability based on models incorporating current conditions associated with fossil preservation and discovery as predictors. However, combining the outputs from climate-envelope, preservation, and discovery models resulted in the most accurate predictions of potential fossil sites at a continental scale. We proposed potential areas to discover new fossils of Diprotodon, Zygomaturus, Protemnodon, Thylacoleo, and Genyornis, and provide guidelines on how to apply our approach to assist fossil hunting in other continents and geological settings.

Characterisation of the conformational changes in platelet factor 4 induced by polyanions: towards in vitro prediction of antigenicity

Heparin-induced thrombocytopenia (HIT) is the most frequent drug-induced immune reaction affecting blood cells. Its antigen is formed when the chemokine platelet factor 4 (PF4) complexes with polyanions. By assessing polyanions of varying length and degree of sulfation using immunoassay and circular dichroism (CD)-spectroscopy, we show that PF4 structural changes resulting in antiparallel β-sheet content >30% make PF4/polyanion complexes antigenic. Further, we found that polyphosphates (polyP-55) induce antigenic changes on PF4, whereas fondaparinux does not. We provide a model suggesting that conformational changes exposing antigens on PF4/polyanion complexes occur in the hairpin involving AA 32-38, which form together with C-terminal AA (66-70) of the adjacent PF4 monomer a continuous patch on the PF4 tetramer surface, explaining why only tetrameric PF4 molecules express "HIT antigens". The correlation of antibody binding in immunoassays with PF4 structural changes provides the intriguing possibility that CD-spectroscopy could become the first antibody-independent, in vitro method to predict potential immunogenicity of drugs. CD-spectroscopy could identify compounds during preclinical drug development that induce PF4 structural changes correlated with antigenicity. The clinical relevance can then be specifically addressed during clinical trials. Whether these findings can be transferred to other endogenous proteins requires further studies.

Correlates of social support in young adults with advanced cancer

OBJECTIVE

This study examined the relationship between perceived social support, quality of life (QoL), and grief in young adults with advanced cancer.

METHODS

Seventy-one young adults (20-40 years) with advanced cancer were administered measures of social support, QoL, and grief. Regression analyses examined the relationship between social support and QoL and grief.

RESULTS

Higher levels of total social support were associated with better psychological and existential QoL and less severe grief. Availability of someone to talk to about problems was also associated with better psychological and existential QoL and less severe grief. Tangible support was associated with better psychological and existential QoL. Availability of someone to engage in activities with was only associated with better existential QoL.

CONCLUSIONS

These results suggest that enhancing social support may improve psychological well-being in this population. In addition, specific types of social support may be particularly relevant to the psychological well-being of young adults with advanced cancer.

Pressure/Temperature/Reaction Phase Diagrams for Several Nitramine Compounds

Pressure/temperature/reaction phase diagrams for several nitramine compounds, including hexanitrohexaazaisowurtzitane (HNIW), 1,3,5-trinitrohexahydro-l,3,5-triazine (RDX), ammonium dinitramide (ADN), and p-nitroaniline (PNA) are presented. A diamond anvil cell was used in conjunction with optical polarizing light microscopy (OPLM), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray diffraction (EDXD), and micro FT-Raman spectroscopy to determine these diagrams. A description is given of the diamond anvil cell and the associated techniques employed.

High-Pressure Single-Crystal Studies of Ice VI

By means of a precession camera incorporating a diamond-anvil high-pressure cell, x-ray diffraction data can be obtained from single crystals of ice VI produced and maintained under high pressures. The cell constants for ice VI at room temperature and approximately 9 kilobars are: a = 8.38 A, b = 6.17 A, c = 8.90 A. The unit cell is orthogonal and the space-group aspect is compatible with P**a. These data for single crystals agree with previously reported unindexed data obtained for polycrystalline ice VI, within the limits of experimental error. The single crystals of ice VI were grown in a diamond-anvil pressure cell, distilled water and a metal gasket being used.

Crystal Structure of Benzene II at 25 Kilobars

Crystals of a high-pressure form of benzene (benzene 11) were grown in the diamond-anvil pressure cell at elevated temperature and pressure from the transition of solid I to solid II. X-ray precession data were obtained from a single-crystal in the high-pressure cell. At 21 degrees C and about 25 kilobars, benzene II crystallizes in the monoclinic system with a = 5.417 +/- 0.005 angstroms (S.D.), b = 5.376 +/- 0.019 angstroms, c = 7.532 +/- 0.007 angstroms, beta = 110.00 degrees +/- 0.08 degrees , space group P2(1)/ c, Pc= 1.26 grams per cubic centimeter. The crystal structure was solved by generating all possible molecular packing configurations and calculating structure factors, reliability factors, and packing energies for each configuration. This procedure produced a unique solution for the molecular packing of benzene II.

Induction of apoptosis in human promyelocytic leukemia cells by a natural trachylobane diterpene

BACKGROUND

Trachylobane diterpenes are secondary metabolites, quite rare in nature, and their bioactivities are poorly understood. Recently, we have described the cytotoxic activity of ent-trachyloban-3beta-ol isolated from the leaves of Croton zambesicus, a plant used in African folk medicine.

MATERIALS AND METHODS

Cell viability on several cell lines, cell morphology, DNA laddering, annexin Vand caspase-3 activation experiments were undertaken in order to analyse the cytotoxicty of trachylobane diterpene and to determine if this compound is able to induce apoptosis.

RESULTS

ent-Trachyloban-3beta-ol exerts a dose-dependent cytotoxic effect, which varies between cell lines. Induction of apoptosis in HL-60 cells could be detected at a concentration of 50 microM after 24-h treatment.

CONCLUSION

We show here, for the first time, that a trachylobane diterpene is able to induce apoptosis in human promyelocytic leukemia cells via caspase-3 activation in a concentration-dependent manner.

A multicentre, double blind, randomised, placebo controlled trial of anakinra (Kineret), a recombinant interleukin 1 receptor antagonist, in patients with rheumatoid arthritis treated with background methotrexate

OBJECTIVE

To assess the efficacy and safety of 100 mg daily anakinra (Kineret), a recombinant form of the naturally occurring interleukin 1 receptor antagonist, plus methotrexate (MTX) in reducing the signs and symptoms of rheumatoid arthritis (RA).

METHODS

Patients with active RA (n = 506) despite current treatment with MTX were enrolled in this multicentre, double blind, randomised, placebo controlled study. Patients received subcutaneous injections of anakinra 100 mg/day or placebo. They were assessed monthly for 6 months for improvement in signs and symptoms of RA and for adverse events. The primary efficacy measure was the percentage of patients attaining ACR20 response at week 24.

RESULTS

Significantly greater proportions of patients treated with anakinra compared with placebo achieved ACR20 (38% v 22%; p<0.001), ACR50 (17% v 8%; p<0.01), and ACR70 (6% v 2%; p<0.05) responses. The response to anakinra was rapid; the proportion of patients with an ACR20 response at the first study assessment (4 weeks) was twice as high with anakinra as with placebo (p<0.005). Clinically meaningful and statistically significant responses were also seen in individual components of the ACR response (for example, Health Assessment Questionnaire, pain, C reactive protein levels, and erythrocyte sedimentation rate). Anakinra was well tolerated, with a safety profile, similar to that of placebo with one exception: mild to moderate injection site reactions were more common with anakinra than with placebo (65% v 24%).

CONCLUSIONS

This study confirms previous observations from a dose-ranging study showing that anakinra, in combination with MTX, is an effective and safe treatment for patients with RA who have inadequate responses to MTX alone.

Cytotoxic aporphine alkaloids from Cassytha filiformis

Purification of a cytotoxic crude alkaloid extract of Cassytha filiformis led to the isolation of four known aporphine alkaloids: neolitsine, dicentrine, cassythine (= cassyfiline) and actinodaphnine. Their structures were determined by analysis of spectroscopic data. All isolated alkaloids were tested for their cytotoxic activities on cancer and non-cancer cell lines in vitro. Neolitsine was the most active against HeLa and 3T3 cells (IC 50 :21.6 microM, and 21.4 microM, respectively). Cassythine and actinodaphnine showed the highest activity against Mel-5 (IC 50 : 24.3 microM and 25.7 microM, respectively) and HL-60 (IC 50 : 19.9 microM and 15.4 microM, respectively). This is the first report on the cytotoxic activity of C. filiformis extract and of neolitsine and cassythine. Furthermore, the complete NMR data of cassythine and actinodaphnine are given here for the first time.

ent-trachyloban-3beta-ol, a new cytotoxic diterpene from Croton zambesicus

The dichloromethane extract of leaves of Croton zambesicus (Euphorbiaceae) showing in vitro cytotoxicity against human cervix carcinoma cells was investigated in order to identify its active compounds. A bio-guided fractionation by HSCCC followed by MPLC led us to isolate a trachylobane diterpene, ent-trachyloban-3beta-ol, with cytotoxic properties (IC50 on HeLa cells = 7.3 microg/ml). This is the first report on the cytotoxicity of a trachylobane diterpene.

[An approach for comparative quantification of myocardial blood flow (O-15-H2O-PET), perfusion (Tc-99m-tetrofosmin-SPECT) and metabolism (F-18-FDG-PET)]

AIM

In the present study a new approach has been developed for comparative quantification of absolute myocardial blood flow (MBF), myocardial perfusion, and myocardial metabolism in short-axis slices.

METHODS

42 patients with severe CAD, referred for myocardial viability diagnostics, were studied consecutively with 0-15-H2O PET (H2O-PET) (twice), Tc-99m-Tetrofosmin SPECT (TT-SPECT) and F-18-FDG PET (FDG-PET). All data sets were reconstructed using attenuation correction and reoriented into short axis slices. Each heart was divided into three representative slices (base, midventricular, apex) and 18 ROIs were defined on the FDG PET images and transferred to the corresponding H2O-PET and TT-SPECT slices. TT-SPECT and FDG-PET data were normalized to the ROI showing maximum perfusion. MBF was calculated for all left-ventricular ROIs using a single-compartment-model fitting the dynamic H2O-PET studies. Microsphere equivalent MBF (MBF_micr) was calculated by multiplying MBF and tissue-fraction, a parameter which was obtained by fitting the dynamic H2O-PET studies. To reduce influence of viability only well perfused areas (> 70% TT-SPECT) were used for comparative quantification.

RESULTS

First and second mean global MBF values were 0.85 ml x min-1 x g-1 and 0.84 ml x min-1 x g-1, respectively, with a repeatability coefficient of 0.30 ml x min-1 x g-1. After sectorization mean MBF_micr was between 0.58 ml x min-1 x ml-1 and 0.68 ml x min-1 x ml-1 in well perfused areas. Corresponding TT-SPECT values ranged from 83% to 91%, and FDG-PET values from 91% to 103%. All procedures yielded higher values for the lateral than the septal regions.

CONCLUSION

Comparative quantification of MBF, MBF_micr, TT-SPECT perfusion and FDG-PET metabolism can be done with the introduced method in short axis slices. The obtained values agree well with experimentally validated values of MBF and MBF_micr.

Dosimetry of a 188rhenium-labeled self-expanding stent for endovascular brachytherapy in peripheral arteries

PURPOSE

Radioactive stents have been proposed as endovascular irradiation device to prevent in-stent restenosis by inhibiting neointimal proliferation. 32P-stents have been used in several studies so far, but require large-scale labeling procedures and endovascular barotrauma for stent expansion supporting the development of edge restenosis. Purpose of this study was to establish dosimetry of a self-expanding nitinol stent for peripheral vascular disease, which was radiolabeled with 188rhenium (188Re) by a dip coating technique.

METHODS AND MATERIALS

The surface of nitinol Memotherm FLEXX stents was polymer-coated providing functional NH(2) groups for diethylenetriaminepentaacetic acid (DTPA) binding, providing the ligand for the complexation of 188Re onto the stent surface. Stability of radiolabeling was tested over 48 h using an in vitro blood circulation (Chandler Loop). Radial and longitudinal dose distributions of a radiolabeled stent were obtained with a plastic scintillator dosimetry system.

RESULTS

Stents with a length of 30 mm and a diameter of 8 mm were labeled with up to 33 MBq 188Re. A total of 69+/-4% of the labeled 188Re remained stable on the stent surface after 48 h. Ninety-five percent of the infinitely accumulated dose was supplied to the target tissue within 72 h. Including correction for radioactivity washout from the stent, the infinitely accumulated dose at 1 mm radial distance from the stent surface was 1.85+/-0.19 Gy/MBq 188Re/cm stent length.

CONCLUSIONS

We developed a technique for radiolabeling of self-expanding nitinol stents with 188Re by dip coating and formation of 188Re chelate complexes. We provide dosimetry data useful for application of this beta-emitting stent for endovascular brachytherapy in peripheral vascular occlusive disease.

[Characterization of therapy failures in radioiodine therapy of Graves' disease without simultaneous antithyroid agents]

Aim of this study was a characterization of radioiodine therapy (RIT) failures in Graves' disease without simultaneous carbimazole.

METHOD

226 patients with a confirmed diagnosis of Graves' disease received 686.8 +/- 376.4 MBq of iodine-131 orally for thyroid ablation. Target dose was 250 Gy. All patients were followed up for 6 months. Therapy failures were compared with successes regarding possible influencing variables initial thyroid volume, thyroid function, immune activity (TRAb), I-131 uptake, effective half-life, absorbed energy dose, age and gender.

RESULTS

212 of 226 patients (93.8%) were treated successfully, 14 (6.2%) showed a hyperthyroidism relapse within 6 months which required a second radioiodine therapy. A success rate of 92.5% (62/67) could also be achieved with 67 patients who were hyperthyroid at the time of RIT. Compared to the therapy successes, the 14 failures achieved significantly lower absorbed doses (223.8 +/- 76.6 Gy vs. 285.2 +/- 82.1 Gy, p < 0.005), but with no significant differences regarding age, thyroid volume, function or TRAb (all p > 0.2). Of the 14 failures, n = 8 reached an absorbed dose < 200 Gy and n = 1 a dose < 250 Gy, although 5 of the failures reached an absorbed dose of > 250 Gy. Stepwise logistic regression revealed only absorbed energy dose as a variable significantly influencing therapy success (p < 0.005), but no influence of initial thyroid volume, function, TRAb value, age (all p > 0.2) or gender (p = 0.13). Two-tailed Fisher's exact test showed no significant influence of gender on success rates (failures/successes: male 1/36, female 13/176, p = 0.48).

CONCLUSIONS

Except for the absorbed energy dose, no other significant variable influencing the outcome of radioiodine therapy in Graves' disease without simultaneous carbimazole could be found. It should be noted, though, that 5 therapy failures (2.2%) reached an absorbed energy dose of > 250 Gy.

Implantable spinal fusion stimulator: assessment of MR safety and artifacts

The objective of this investigation was to perform magnetic resonance (MR) imaging safety and artifact testing of an implantable spinal fusion stimulator. Magnetic field interactions, artifacts, and operational aspects of an implantable spinal fusion stimulator were evaluated in association with a 1.5 T MR system. Magnetic field-related translational attraction was measured using the deflection angle test. A special test apparatus was used to determine torque at 4.7 T. Artifacts were characterized using fast multiplanar spoiled gradient-echo, T1-weighted spin-echo, and T1-weighted fast spin-echo sequences. Operational aspects of the implantable spinal fusion stimulator before and after exposure to MR imaging at 1.5 T were assessed. In addition, nine patients (six lumbar spine and three cervical spine) with implantable spinal fusion stimulators underwent MR imaging. The findings indicated that magnetic field interactions were relatively minor, artifacts were well characterized and should not create diagnostic problems, and there were no changes in the operation of the spinal fusion stimulator. The nine patients underwent MR procedures without substantial adverse events or complaints. Based on the results of this investigation and in consideration of the findings from previous studies of MR imaging safety for the implantable spinal fusion stimulator, MR imaging may be performed safely in patients using MR systems operating at 1.5 T or less following specific recommendations and precautions.

[Angiomyolipoma of the liver]

HISTORY AND ADMISSION FINDINGS

A 66-year-old woman, known for 4 years to have a space-occupying lesion in the liver thought to be a lipoma, was admitted because the increasing size of the mass. She was hypertensive and had recurrent supraventricular tachycardia, but was otherwise asymptomatic and physical examination was unremarkable.

INVESTIGATIONS

Laboratory tests were within normal limits. Abdominal ultrasound demonstrated a well-circumscribed, echodense space-occupying lesion. Magnetic resonance imaging revealed a hyperintense encapsulated tumour with contrast-medium enhancement.

DIAGNOSIS AND TREATMENT

Because the imaging tests were equivocal, a segmental liver resection was performed to exclude malignancy. Histological examination revealed an angiomyolipoma of the liver.

CONCLUSION

Angiolipoma is a benign mixed-cell tumour that very rarely affects the liver but must be included in the differential diagnosis of hepatic space-occupying lesions. Its manifestations may be highly variable and histological examination is required if there is any uncertainty about possible malignancy. If the biopsy is diagnostic of a benign lesion, expectant observation with regular monitoring is indicated.

Renal handling of drugs in the healthy elderly. Creatinine clearance underestimates renal function and pharmacokinetics remain virtually unchanged

OBJECTIVE

It is commonly assumed that renal function, and in parallel the excretion of drugs, is considerably reduced in the elderly. Endogenous creatinine clearance or indirect estimates of this parameter are generally recommended for adapting drug dosage. The present study evaluates the validity of both assumptions.

METHODS

We compared pharmacokinetics (and pharmacodynamics) of 50 mg atenolol, 800 mg piracetam and 25 mg hydrochlorothiazide plus 50 mg triamterene in ten healthy young [25 (2) years] and 11 healthy elderly subjects [68 (5) years]. Inulin (Cin) and para-aminohippurate [PAH (CPAH)] clearance (infusion clearance technique), endogenous (C(Cr)) and calculated (Cockroft-Gault) creatinine clearance, analysis of drugs and their metabolites (HPLC), were performed. Renal haemodynamics and the pharmacokinetics of beta-adrenergic blocking agent, diuretics and the nootropic agent piracetam, respectively, were measured on separate days.

RESULTS

Cin was significantly (P < 0.01) lower in the healthy elderly subjects [104 (12) vs 120 (14) ml x min(-2) x 1.73 m(-2) in the young], but remained within the normal range (> 90 ml x min(-2) x 1.73 m(-2)). In contrast, C(Cr) was even lower in healthy elderly subjects [95 (24) vs 121 (20) ml x min(-1) in the young], and the Cockroft-Gault clearance underestimated true glomerular filtration rate (GFR) even more seriously [74 (17) vs 122 (16) ml min(-1)]. For atenolol the mean area under the curve (AUC) was similar in both groups [3.16 (0.48) microg x h(-1) x ml(-1) in the elderly vs 3.01 (0.30) in the young], as was the mean maximal plasma concentration [0.42 (0.07) vs 0.44 (0.06) microg x ml(-1)], but the proportion of the drug excreted in urine was marginally (P < 0.025) lower in the elderly. Similar results were obtained for hydrochlorothiazide, whereas no marked differences between the groups were found for triamterene and its metabolite. Furthermore, the pharmacodynamic action of diuretics was not significantly altered in the elderly.

CONCLUSIONS

The true GFR of the healthy elderly remains within the normal range and is underestimated by creatinine clearance and more so by its surrogate (Cockroft-Gault clearance). In parallel, pharmacokinetics of renally excreted drugs are not affected in the healthy elderly to a clinically significant extent. For drugs with a narrow therapeutic window, indirect estimates of GFR appear to be an unreliable means for calculating correct dosage in the elderly.

Nurturing humanism through teaching palliative care

After many years of neglect by the medical establishment, the discipline of palliative medicine is finally moving into academic health centers (AHCs). While hospice programs have cared for dying patients in the community for years with little input from mainstream medicine, palliative care is gaining a foothold in AHCs, challenging these centers to integrate the hospice approach with biomedicine. The discipline of palliative care promises to be a rich source of learning and growth for physicians-in-training. Teaching about palliative care affirms two essential but vulnerable dimensions of the practice of medicine--the importance of relationship-centered care and the value of doctoring as a source of meaning and growth for physicians. In addition to fostering fundamental humanistic learning, palliative medicine is an excellent vehicle for teaching basic but often neglected clinical competencies, including pain and symptom control, communication, and working as part of a health care team. Because palliative care settings offer extraordinary learning opportunities, the authors recommend that clinical experiences in palliative care be integrated into the core curricula of all medical schools as well as appropriate residency programs.

[Granisetron (per os) compared with ondansetron (per os) in the prevention of nausea and vomiting induced by mildly emetogenic chemotherapies. Groupe de Recherches en Cancerologie du Nord]

It is a randomised cross-over multicenter study comparing the efficacy and the tolerance of granisetron (Gra) 1 mg and ondansetron (Ond) 8 mg, oral, given during two consecutive cycles to 188 naive patients scheduled to receive a moderately emetogenic chemotherapy. The antiemetic treatment is given one day per course, 1 hour before chemotherapy and the second administration from 8 to 12 hours after the beginning, during each of the two cycles; alternatively according to the randomisation. Five criteria are assessed; nausea (ordinal and visual analogic scales), emeric episodes (vomiting orland retching), complete response (minor or no nausea, no emetic episode and no rescue treatment), patient preference and tolerance. The intent to treat analysis showed no significant difference at cycle 1 between Gra and Ond; at cycle 2, there is no significant difference in the number of emetic episodes; for the prevention of nausea, the ordinal scale shows a significant difference (p = 0.028 in favour of Gra at day 1 (D1) but not from D2 to D5. Gra induced more complete response than Ond at D1 (p = 0.028), but not from D2 to D5. The cross-over study did not show any period or order effect, whereas a treatment effect on Ond was significant in favour of Gra (p = 0.01). There is no significant patients preference in favour of Gra or Ond. In conclusion, Gra was more efficient in preventing nausea and obtaining complete response on the first day of treatment, significantly at the second cycle. Both Gra and Ond had a good antiemetic activity for moderately emetogenic chemotherapy with complete response rates always over 50% on day 1; delayed emesis remain less weli controlled.

Infant immunization with pneumococcal CRM197 vaccines: effect of saccharide size on immunogenicity and interactions with simultaneously administered vaccines

Six pentavalent pneumococcal conjugate vaccines (Pn-CRM197) were evaluated among 400 infants. The vaccines differed in saccharide chain length (oligosaccharide [OS] or polysaccharide [PS]) and saccharide quantity (0.5, 2, or 5 microg). Subjects were randomized into groups 1-6 (Pn-CRM197 recipients) or 7 (controls) for immunization at 2, 4, and 6 months of age. Pn-CRM197 were well tolerated and elicited mean antibody concentrations that exceeded those in controls for all 5 capsular serotypes. PS formulations were generally more immunogenic than their OS counterparts. For PS vaccines, a dose-response was documented (5 microg > 2 microg > 0.5 microg), but the differences between the 5- and 2-microg formulations were insignificant. The mean anti-PRP antibody concentration was significantly higher among Pn-CRM197 recipients. It is concluded that PS vaccines are more immunogenic than OS vaccines. The improved immunogenicity from Haemophilus type b oligosaccharide conjugate (HbOC) vaccine when given with Pn-CRM197 suggests that a decreased dose of HbOC vaccine may be sufficient to elicit protection.

Renal function in the elderly: impact of hypertension and cardiac function

In senescence renal function is thought to decline markedly even in the absence of renal disease. It has also been proposed that the changes in renal function with age are not uniform and that confounding factors such as hypertension or atherosclerosis may play a role. We performed a comprehensive study to compare several aspects of renal function in four groups: (i) young healthy normotensive subjects (N = 24; 13 males; mean age 26 +/- 3 years); (ii) elderly healthy normotensive subjects (elderly NT; N = 29; 13 males; 68 +/- 7 years); (iii) elderly treated and untreated hypertensive patients (elderly HT; N = 25; 13 males; 70 +/- 6 years); and (iv) elderly patients with compensated mild to moderate heart failure (elderly HF; N = 14; 6 males; 69 +/- 6 years). Compared to young subjects mean GFR (C(In)) and ERPF (C(PAH)) were significantly lower in the elderly, despite similar mean plasma creatinine levels (young, 121 +/- 11, 650 +/- 85 ml/min/1.73 m2; elderly NT, 103 +/- 11, 486 +/- 102; elderly HT, 103 +/- 13, 427 +/- 55; elderly HF, 92 +/- 14, 377 +/- 103). Nevertheless, GFR was within the normal range in the majority of elderly NT and HT, but not in elderly HF. ERPF was significantly lower in elderly HT as compared with elderly NT, and still lower in elderly HF. Mean renovascular resistance and filtration fraction were significantly higher in the elderly, particularly in elderly HT and HF as compared with the young. Mean fractional excretion of Na+ was similar in all groups studied, but the lithium clearance was significantly lower in the elderly, suggesting a greater proximal and less distal sodium reabsorption in senescence. In the elderly, mean PTH concentration and urinary excretion of pyridoline cross-links were significantly higher and mean 25-(OH)D3, calcitriol and phosphate concentrations significantly lower; the correlation between PTH and GFR was significant (r = -0.432, P < 0.001). The results document that the decrease in renal hemodynamics with senescence is less marked than suggested by some studies using less stringent methodology and inclusion criteria. Comorbid conditions confound renal function in the elderly. Age-associated changes in renal hemodynamics are accompanied by significant alterations of renal hormones and of renal sodium handling.

Mycoplasma pneumoniae and Chlamydia pneumoniae in pediatric community-acquired pneumonia: comparative efficacy and safety of clarithromycin vs. erythromycin ethylsuccinate

We evaluated 260 previously healthy children ages 3 through 12 years who had clinical signs and symptoms of pneumonia, radiographically confirmed. Patients were randomized 1:1 to a 10-day course of either clarithromycin suspension 15 mg/kg/day divided twice a day or erythromycin suspension 40 mg/kg/day divided twice a day or three times a day. Evidence of infection with Chlamydia pneumoniae was detected in 28% (74) of patients: 13% (34) by nasopharyngeal culture and 18% (48) by serology with the microimmunofluorescence assay. Evidence of infection with Mycoplasma pneumoniae was detected in 27% (69) of patients: 20% (53) by nasopharyngeal culture or polymerase chain reaction and 17% (44) by serology with the use of enzyme-linked immunosorbent assay. Serologic confirmation of infection was observed in 23% (8) and 53% (28) of patients with bacteriologically detected C. pneumoniae and M. pneumoniae, respectively. Treatment with clarithromycin vs. erythromycin, respectively, yielded the following outcomes: clinical success 98% (121 of 124) vs. 95% (105 of 110); radiologic success 98% (109 of 111) vs. 94% (92 of 110); and eradication by pathogen, C. pneumoniae 79% (15 of 19) vs. 86% (12 of 14) and M. pneumoniae 100% (9 of 9) vs. 100% (4 of 4). Adverse events were primarily gastrointestinal occurring in almost one-fourth of patients in both groups, and were mild to moderate in severity. Clarithromycin and erythromycin were similarly effective and safe for the treatment of radiographically proved, community-acquired pneumonia in children older than 2 years old.(ABSTRACT TRUNCATED AT 250 WORDS)

Methotrexate in rheumatoid arthritis. A five-year prospective multicenter study

OBJECTIVE

To evaluate the efficacy and tolerability of oral methotrexate (MTX) in rheumatoid arthritis (RA) in a long-term prospective trial.

METHODS

One hundred twenty-three patients with RA who completed a 9-month multicenter randomized trial comparing MTX and auranofin enrolled in this 5-year prospective study of MTX.

RESULTS

Significant (P = 0.0001) improvement compared with baseline was noted in all clinical disease variables, functional status, and the Westergren erythrocyte sedimentation rate (ESR). "Marked improvement" occurred in 87 (71%) and 85 (69%) of the patients, respectively, in the joint pain/tenderness index and the joint swelling index at the last evaluable visit. Forty-four patients (36%) withdrew during the study. Eight (7%) withdrew due to lack of efficacy, and 8 (7%) due to adverse experiences, including 1 patient with cirrhosis. At 5 years, 64% of patients were still taking MTX and completed the study.

CONCLUSION

This large prospective study of long-term MTX treatment demonstrates sustained clinical response and improvement in the Westergren ESR and functional assessment scores, with an acceptable toxicity profile.

Managing patient demographics

The Harvard Community Health Plan commissioned a cross-functional project team to improve the accuracy of the members' data base because inaccurate patient phone numbers and addresses were a major obstacle for clinicians seeking to provide high-quality service to patients. Accurate demographic information is essential to enable clinicians to contact patients quickly regarding lab results or follow-up care. The team members applied a quality improvement problem-solving methodology that required them to focus on the few vital problems and to test problems using data analysis. As a result, the team saw firsthand that staff members were not to blame for the inaccurate demographic information; the problem was in the automated system that obtains, updates, and maintains the records.