Treatment outcomes for older patients with relapsed/refractory aggressive lymphoma receiving salvage chemotherapy and autologous stem cell transplantation are similar to younger patients: a subgroup analysis from the phase III CCTG LY.12 trial

Background

High-dose therapy and autologous stem cell transplantation (ASCT) is often considered for older patients (age >60 years) with relapsed/refractory aggressive lymphomas. Although registry data support the safety and potential efficacy of this approach, there are no prospective trials evaluating outcomes of ASCT in older patients. We evaluated the result of second-line chemotherapy and ASCT in older versus younger patients in the CCTG randomized LY.12 trial.

Patients and methods

From August 2003 to November 2011, 619 patients with relapsed/refractory aggressive lymphoma were randomized to gemcitabine, dexamethasone, cisplatin (GDP) or dexamethasone, cytarabine, cisplatin (DHAP); 177 patients (28.6%) enrolled were >60.0 years of age (range, 60-74) and 442 were ≤60.0 years of age. After two to three cycles, responding patients proceeded to ASCT. Intention-to-treat analysis was used to compare response rate, transplantation rate, event-free survival (EFS) and overall survival (OS) between patients aged ≤60.0 and >60.0 years.

Results

Patient characteristics were comparable between the two cohorts, except a larger proportion of older patients had high International Prognostic Index risk scores. Response to salvage therapy was 48.6% for patients aged  >60.0 versus 43.0% for those aged  ≤60.0 (P = 0.21). Transplantation rates were also similar: 50.3% versus 49.8% (P = 0.87) for older versus younger patients. Rates of febrile neutropenia and adverse events requiring hospitalization were comparable for older and younger patients (30.5% versus 22.9% and 37.9% versus 32.1%, respectively). With a median follow-up of 53 months, there was no difference in 4-year OS (36% and 40% for patients aged >60.0 and ≤60.0 years, P = 0.42), or 4-year EFS (20% versus 28%, P = 0.43). Mortality from salvage therapy was 8/174 (4.60%) and 5/436 (1.15%), and 100-day mortality post-ASCT was 7/88 (8.06%) and 4/219 (1.85%).

Conclusion

This subgroup analysis suggests that older patients derive similar benefit from salvage therapy and ASCT to younger patients, with acceptable toxicity.

ClinicalTrials.gov Identifier

NCT00078949.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Impact of nucleation on step-meandering instabilities during step-flow growth on vicinal surfaces

Step-meandering instabilities can manifest during step-flow growth on vicinal surfaces [Bales and Zangwill, Phys. Rev. B 41, 5500 (1990); Pierre-Louis, D'Orsogna, and Einstein, Phys. Rev. Lett. 82, 3661 (1999)]. A phase diagram based on the various growth regimes of a vicinal surface allows us to study the impact of nucleation on these meanders and to predict a meandering instability caused by the nucleation and the coalescence of both islands and steps. Using an accelerated kinetic Monte Carlo method, we find that the coalescence of islands with steps produces large protrusions and deep ripples and that the resulting meandering instability is reinforced by the growth of the islands at almost the same positions from one monolayer to the other. A coarsening phenomenon occurs for the instability wavelength until mounds appear, favored by a large Ehrlich-Schwoebel barrier. Such a meandering instability could be exploited for periodic self-assembly.

Carbon nanotubes as injection electrodes for organic thin film transistors

We have investigated the charge injection efficiency of carbon nanotube electrodes for organic semiconducting layers and compared their performance to that of traditional noble metal electrodes. Our results reveal that charge injection from a single carbon nanotube electrode is more than an order of magnitude more efficient than charge injection from metal electrodes. Moreover, organic thin film transistors that use arrays of carbon nanotube electrodes display considerable effective mobilities (0.14 cm(2)/(V.s)) and nearly ideal linear output characteristics. These results indicate that carbon nanotubes should be considered a viable alternative to metal electrodes for next-generation organic field-effect transistors.

Destabilizing and stabilizing forces to assess equilibrium during everyday activities

Postural stability is essential to functional activities. This paper presents a new model of dynamic stability which takes into account both the equilibrium associated with the body position over the base of support (destabilizing force) and the effort the subject needs to produce to keep his/her centre of mass inside the base of support (stabilizing force). The ratio between these two forces (destabilizing over stabilizing) is calculated to provide an overall index of stability for an individual. Preliminary results from data collected during walking at preferred and maximal safe speed in four older adults (aged from 64 to 84yr) showed that both forces are lower for subjects with reduced maximal gait speed. In addition, the stabilizing force increases by 2-3 times from preferred to maximal speed, while the destabilizing force barely changes with gait speed. Overall, the model through the index of stability attributes lower dynamic stability to subjects with lower maximal gait speed. These preliminary results call for larger-scale studies to pursue the development and validation of the model and its application to different functional tasks.

Mechanism of the far-infrared absorption of carbon-nanotube films

The far-infrared conductivity of single-wall carbon-nanotube ensembles is dominated by a broad absorption peak around 4 THz whose origin is still debated. We observe an overall depletion of this peak when the nanotubes are excited by a short visible laser pulse. This finding excludes optical absorption due to a particle-plasmon resonance and instead shows that interband transitions in tubes with an energy gap of approximately 10 meV dominate the far-infrared conductivity. A simple model based on an ensemble of two-level systems naturally explains the weak temperature dependence of the far-infrared conductivity by the tube-to-tube variation of the chemical potential.

Electroluminescence from single-wall carbon nanotube network transistors

The electroluminescence (EL) properties from single-wall carbon nanotube network field-effect transistors (NNFETs) and small bundle carbon nanotube field effect transistors (CNFETs) are studied using spectroscopy and imaging in the near-infrared (NIR). At room temperature, NNFETs produce broad (approximately 180 meV) and structured NIR spectra, while they are narrower (approximately 80 meV) for CNFETs. EL emission from NNFETs is located in the vicinity of the minority carrier injecting contact (drain) and the spectrum of the emission is red shifted with respect to the corresponding absorption spectrum. A phenomenological model based on a Fermi-Dirac distribution of carriers in the nanotube network reproduces the spectral features observed. This work supports bipolar (electron-hole) current recombination as the main mechanism of emission and highlights the drastic influence of carrier distribution on the optoelectronic properties of carbon nanotube films.

Effects of long jumps, reversible aggregation, and Meyer-Neldel rule on submonolayer epitaxial growth

We demonstrate, using kinetic Monte Carlo simulations of submonolayer epitaxial growth, that long jumps and reversible aggregation have a major impact on the evolution of island morphologies. Long jumps are responsible for a supra-Arrhenius behavior of the effective diffusion coefficient as the attachment and detachment kinetics give rise to a bimodal island size distribution that depends on temperature and long jump extent limits. As the islands density increases with temperature, the average size of stable islands reaches a maximum before decreasing. We have also observed that the diffusion coefficient cannot be used alone to predict the evolution of island sizes and morphologies, the relative rate of each process having a major importance. Our theoretical developments are of direct relevance for materials systems such as Au, Pd, Ag, Cu, Ni, H/Si , H/W(110), Co/Ru , and Co/Ru(S), that are known for exhibiting a compensation effect that cannot be contained within experimental uncertainties.

Self-organization of InAs/InP quantum dot multilayers: pseudophase diagram describing the transition from aligned to antialigned structures

Based on experimental observations for the InAs/InP(001) system and atomistic strain calculations using Keating's valence force field method, we propose a pseudophase diagram describing the regimes of 3D self-organization in quantum dot (QD) multilayers. The combined experimental and theoretical analyses--varying the spacer thickness (H), QD height (h), base (b), and lateral spacing (D)--indicate that the vertically aligned to antialigned transition occurs for a critical value of H/D which increases weakly with b/D, while varying h has virtually no effect on the transition point.

Evaluation of a hybrid system for three-dimensional measurement of trunk posture in motion

Ambulatory assessment of trunk posture is important in improving our understanding of the risk of low back injury. Recently, small inertial sensors combining accelerometers, gyroscopes and magnetometers were developed and appear to be promising for measuring human movement. However, the validity of such sensors for assessing three-dimensional (3D) trunk posture in motion has not been documented. The purpose of this study was to evaluate a hybrid system (HS) composed of two inertial sensors for the 3D measurement of trunk posture. A secondary purpose was to explore the utility of adding another source of information, a potentiometer, to measure the relative rotation between both sensors in order to improve the validity of the system. The first sensor was placed over the sacrum and the second on the upper part of the thorax. Both sensors were linked by a flexible rod with a potentiometer. A complementary quaternion filter algorithm was used to estimate trunk orientation by taking advantage of the nine components of each sensor and the potentiometer. The HS's orientations were compared to those obtained from a 3D optoelectronic system. Validation of the HS was performed in three steps in which six subjects had to perform manual handling tasks in: (1) static postures; (2) dynamic motions of short duration (30s); and (3) dynamic motions of long duration (30min). The results showed that the root mean square (RMS) error of the HS was generally below 3 degrees for the flexion and lateral bending axes, and less than 6 degrees for the torsion axis, and that this error was lower for the short-duration tests compared to the long-duration one. The potentiometer proved to be an essential addition, particularly when the magnetometer signals were corrupted and only the gyroscope and accelerometer could be combined. It is concluded that the HS can be a useful tool for quantifying 3D trunk posture in motion.

A phase III study of Æ-941 with induction chemotherapy (IC) and concomitant chemoradiotherapy (CRT) for stage III non- small cell lung cancer (NSCLC) (NCI T99–0046, RTOG 02–70, MDA 99–303)

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Background: Æ-941 is a shark cartilage extract with antiangiogenic properties. We conducted a placebo-controlled trial testing Æ-941, with IC and CRT, in unresectable stage III NSCLC. Methods: Eligibility criteria included performance status (PS) < 2, weight loss < 10%. Subjects received one of two treatment regimens depending on site of enrollment: carboplatin (C) (AUC 6) and paclitaxel (P) (200 mg/m2) × 2 cycles followed by CRT (60 Gy/30 fractions) with weekly C (AUC 2) and P (45 mg/m2) × 6 doses or cisplatin (CDDP) (75 mg/m2, d1) and vinorelbine (V) (30 mg/m2, d1 and 8) × 2 cycles followed by CRT (60 Gy/30 fractions) with CDDP (75 mg/m2, day 1) and V (15 mg/m2, d1 and 8) × 2 cycles. Subjects were randomized to receive Æ-941 (Arm A) or placebo (Arm B), 120 mL orally twice daily, at the start of IC and continuing after CRT as maintenance therapy. Randomization was stratified for stage, gender, and type of chemotherapy. The primary endpoint was overall survival (OS), with a planned sample size of 756 subjects providing 80% power to detect a 25% difference in OS, assuming a control arm median survival time (MST) of 13 months, type I error 0.05. Results: Between 6/00 and 2/06, 384 subjects were enrolled onto the trial and randomized. In 2/06 the trial was closed to new patient entry due to insufficient accrual. This final analysis is based on 379 randomized and eligible subjects (188 arm A, 191 arm B). Subject characteristics: 60% male, median age 63 years (range 37–84), 56% stage IIIB, 58% C-based chemotherapy, median follow-up 3.7 years. There was no significant difference in OS between arms A and B, with MSTs of 14.4 (95% CI 12.6–17.9) and 15.6 (95% CI 13.8–18.1) months, respectively (log-rank p=0.73). OS by pre-specified stratification factors: stage IIIB vs IIIA (MST 13.9 vs. 17.4 months, p=0.25), C vs. CDDP chemotherapy (MST 14.4 vs. 16.7 months, p=0.13), and male vs. female (MST 15.7 vs. 15.1 months, p=0.74). The study drug was well tolerated. Fewer subjects in arm A experienced grade 3 or higher adverse events (66% vs. 77%, p=0.018). Conclusions: The addition of Æ−941 to IC and CRT does not improve OS in patients with unresectable stage III NSCLC.

No significant financial relationships to disclose.

Ultrafast dynamics of delocalized and localized electrons in carbon nanotubes

We report on the dynamics of the dielectric function of single-wall carbon nanotubes in the 10-30 THz frequency range after ultrafast laser excitation. The absence of a distinct free-carrier response is attributed to the photogeneration of strongly bound excitons in the tubes with large energy gaps. We find a feature of enhanced transmission caused by the blocking of optical transitions in small-gap tubes. The rapid decay of a featureless background with pronounced dichroism is associated with the increased absorption of spatially localized charge carriers before thermalization is completed.

Docetaxel and Gemcitabine administered on days 1 and 8 for metastatic non-small cell lung carcinoma (NSCLC): a phase II multicenter trial

Docetaxel and Gemcitabine are active agents in non-small cell lung carcinoma (NSCLC). They have different mechanism of action, minimal overlapping toxicity, and are easily administered on an outpatient basis. This phase II study evaluated Docetaxel administered with Gemcitabine on days 1 and 8 in a 3-week cycle, to determine its efficacy, while attempting to lower the regimen's toxicity, especially myelosuppression which can occur when Docetaxel is administered at full dose on day 1 only. Forty-three chemonaive patients, 40 evaluable, were entered in this trial between May 2001 and March 2002. Thirty-seven patients had stage IV and three patients had stage III B NSCLC, median age 58 (ages 32-78), median performance status (PS) 1 (range 0-2). They were treated with Docetaxel 36mg/m(2) and Gemcitabine 1000mg/m(2) intravenously on days 1 and 8 in a 3-week cycle. No growth factors were administered. Of 40 evaluable patients, 4 achieved partial response (10%), 25 stable disease (62.5%) and 11 progressive disease (27.5%). Median time-to-disease progression was 15 weeks. Median survival was 7.75 months. One year survival was 32.5% (13 patients). Hematologic toxicity was minimal, non-hematologic toxicity was easily treatable. Docetaxel, when given with Gemcitabine on days 1 and 8 every 3 weeks, is less myelotoxic, yet still an effective treatment for metastatic NSCLC.

Back muscle fatigue during intermittent prone back extension exercise

The purpose of this study was to estimate the level of muscular activation and muscle fatigue of the low back muscles during the performance of an intermittent prone back extension (PBE) exercise. Forty-one healthy students (24 males and 17 females) lying prone on a bench with the legs fixed performed two maximal voluntary contractions (MVC) in extension, a maximum of 100 repetitions of an intermittent PBE exercise immediately followed by a final MVC in extension. In addition, 12 subjects (11 males and one female) repeated the PBE exercise but with the addition of a 45-N weight on the back. The PBE exercise consisted of a task broken into four 1-s segments, while lying prone on a bench (10 degrees below horizontal): (1) raising the trunk to a horizontal position; (2) holding the trunk in the static phase (10 degrees above horizontal); (3) returning to the original position; and (4) resting on the bench. Electromyography (EMG) was used to measure the level of muscle activity (erector spinae (ES), gluteus maximus (GM), hamstrings (HA)) relative to the maximum voluntary EMG (MVE).

RESULTS

Most of the subjects (34 out of 41) completed the 100 repetitions without excessive muscle fatigue according to the post-exercise MVC values. The intermittent PBE increased fatigue in the lumbar and hip extensor muscles in terms of: (1) a decrease in the MVC; (2) an increase in the level of muscle activation; and (3) a decline of the median frequency (MF). There was no gender difference in all EMG measurements. The level of muscle activation in the hip extensors (GM and HA) was associated with task failure (number of repetitions <100) for some subjects and the addition of a weight of 45 N had more impact on HA than ES. In conclusion, the PBE exercise as performed in the present study (including rest intervals), although not very strenuous for our healthy subjects, seems an adequate exercise to measure and train the aerobic capacity of the back muscles. However, to train specifically the back muscles, the exercise must be adjusted to avoid task failure due to possible hip extensor fatigue.

Handling missing marker coordinates in 3D analysis

The use of mathematical formulations to retrieve missing data is not usually implemented as an automated computer procedure. The purpose of this paper is to present a simple mathematical formulation that can be used to retrieve the coordinates of markers hidden during a task. A strategy based on the smoothness of the variation of distance between points is devised, which leads to an automated computer procedure for retrieving hidden skin markers or missing joint coordinates (missing 3D points). This approach has the advantage of not being restricted to the usual rigid-body assumption.

Estimated moments at L5/S1 level and muscular activation of back extensors for six prone back extension exercises in healthy individuals

The purpose of this study was to identify the prone back extension (PBE) exercises that offer the most resistance to the back extensor muscles. Twenty males with no previous history of low back injury performed two repetitions of eight exercises. These consisted of two maximal isometric voluntary activations (MVA) and six different PBE exercises. The participants, while lying prone on a bench, were asked to raise either their trunk or legs to the horizontal position and hold for one second (static phase) before returning to the original position. The exercises differed according to the particular segments that were raised into extension. To assess the PBE exercises, a biomechanical model was used to estimate the level of load resistance (%MVA) relative to the maximum voluntary activation strength (MVA). In addition, electromyography (EMG) was included to measure the level of muscle activity (%MVE) relative to the maximum voluntary activation EMG (MVE) value reached during the MVA. A significant relationship of 0.86 was found between the mass of the subject and the peak reaction moment during the MVA. Peak level of load resistance averaged around 50% MVA with the exception of exercise no. 5 where the subject had to raise in extension his trunk, legs and arms (65% MVA). The erector spinae (ES) activity level reached a peak value of 61% MVE for exercise no. 5. In the exercises where only the trunk was lifted, the peak level of ES was below 47% MVE and the average activity during the static phase reached approximately 26% MVE. For healthy individuals PBE exercises can be considered low intensity exercises (< 50% MVA; except exercise no. 5) and can be used to improve the endurance of the back muscles.

Assessment of a three-dimensional robotic model for biomechanical-data acquisition of human movement

The use of a kinematic robotic model has not been implemented in the biomechanical-data acquisition protocol, as it has in workplace analysis, ergonomics and design. The purpose of this paper was to assess the use of a kinematic model to retrieve frames of human movements from data obtained at a low sampling frequency. From experimental trials with an original sampling frequency of 60 Hz, the data were sampled again at two lower frequencies, 5 Hz and 10 Hz. The model was then used to reconstitute the data to its original frequency (60 Hz). The results demonstrated that it was possible to retrieve a full 3-D human movement from a sampling rate lower than normal without sacrificing accuracy. It was observed from both reduced sampling frequencies that the error level was comparable to the usual accuracy of a DLT 3-D reconstruction technique. It was therefore concluded that the data retrieved from these two frequencies were very similar to the original data sampled at 60 Hz.

Alterations in expression of genes coding for key astrocytic proteins in acute liver failure

Cerebral edema and hepatic encephalopathy are major complications of acute liver failure. Brain herniation caused by increased intracranial pressure as a result of cell swelling is the major cause of death in this condition. Evidence available currently suggests that the rapid accumulation of ammonia by the brain is the major cause of the central nervous system complications of acute liver failure. Increased brain ammonia may cause cell swelling via the osmotic effects of an increase in astrocytic glutamine concentrations or by inhibition of glutamate removal from brain extracellular space. Acute liver failure results in altered expression of several genes in brain, some of which code for important proteins involved in CNS function such as the glucose (GLUT-1) and glutamate (GLT-1) transporters, the astrocytic structural protein glial fibrillary acidic protein (GFAP) the "peripheral-type" benzodiazepine receptor (PTBR) and the water channel protein, aquaporin IV. Loss of expression of GLT-1 results in increased extracellular brain glutamate in acute liver failure. Experimental acute liver failure also results in post-translational modifications of the serotonin and noradrenaline transporters resulting in increased extracellular concentrations of these monoamines. Therapeutic measures currently used to prevent and treat brain edema and encephalopathy in patients with acute liver failure include mild hypothermia and the ammonia-lowering agent L-ornithine-L-aspartate.

A force platform for large human displacements

This paper provides details of a force platform assembly suitable for measuring the magnitude, position and direction of ground reaction forces for manual handling tasks involving several footsteps in any horizontal direction. An approach to increase the natural frequency with the use of a vibration absorber is used; this frequency was found to be 41+/-2 Hz. The results show a maximum error of 22 N (2% of the full scale output) when a person performs repetitive movements from a squat position to a full extension and back to the squat position. Static tests show the maximal errors to be, vertically, 1.5% of the full scale output (1818+/-33 N), and horizontally, 4.9% of the full scale output (1177+/-6 N).

Pathway for the strain-driven two-dimensional to three-dimensional transition during growth of Ge on Si(001)

The two-dimensional (2D) to three-dimensional (3D) morphological transition in strained Ge layers grown on Si(001) is investigated using scanning tunneling microscopy. The initial step takes place via the formation of 2D islands which evolve into small ( approximately 180 A) 3D islands with a height to base diameter ratio of approximately 0.04, much smaller than the 0.1 aspect ratio of 105-faceted pyramids which had previously been assumed to be the initial 3D islands. The "prepyramid" Ge islands have rounded bases with steps oriented along <110> and exist only over a narrow range of Ge coverages, 3.5-3.9 monolayers.

Strategies of load tilts and shoulders positioning in asymmetrical lifting. A concomitant evaluation of the reference systems of axes

OBJECTIVES

To evaluate two handling factors on asymmetry of posture and efforts and to evaluate different reference systems of axes on the characterization of asymmetry.DESIGN. Ten novice workers performed three tasks evaluated for the effects of load tilting (tilts vs no tilts) and shoulders positioning (non-parallel vs parallel to the ground). Specific comparisons were made using three referential systems.BACKGROUND. Box handgrips/tilting and body posture are factors differentiating expert and novice workers which present a potential for reducing asymmetries. The literature also suggests that different conclusions may be reached about asymmetry with different systems of axes.METHODS. Net 3D moments at L5/S1 were obtained from two force platforms, four video cameras and inverse dynamic analyses using three reference systems of axes (trunk, pelvis, and joint).RESULTS. Tilting the load presented clear advantages of reducing the duration and trajectory of efforts, better positioning the load and reducing knee flexion, peak trunk extensors and mechanical work on the load. The maintenance of the shoulders parallel reduced asymmetries of posture and efforts but the results were affected by the type of reference system of axes chosen.CONCLUSIONS. Box tilting and shoulders positioning should be considered in the reduction of risk factors. More research is needed to define referential systems and characterize asymmetry. RelevanceBox tilting and shoulders positioning appear to be two fundamental elements to take into account in the formation programs based on prevention of risk factors. The importance of asymmetry among the risk factors emphasizes the need for better characterization of this risk.

Effects of ammonia on glutamate transporter (GLAST) protein and mRNA in cultured rat cortical astrocytes

Ammonia is a neurotoxic substance which accumulates in brain in liver failure and it has been suggested that ammonia plays a key role in contributing to the astrocytic dysfunction characteristic of hepatic encephalopathy. In particular, the effects of ammonia may be responsible for the reduced astrocytic uptake of neuronally-released glutamate and high extracellular glutamate levels consistently seen in experimental models of hepatic encephalopathy. To further address this issue, [(3)H]-D-aspartate uptake was examined in primary rat cortical astrocyte cultures exposed to 5 mM ammonium chloride for a period of 7 days. In addition, reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot studies were performed to examine the mRNA and protein expression respectively of the glutamate transporter GLAST in ammonia-treated cells. Studies revealed a 57% (p<0.05) decrease in [(3)H]-D-aspartate uptake and a concomitant significant decrease in GLAST transporter protein (43%, p<0.05) and mRNA (32%, p<0.05) expression. The reduced capacity of astrocytes to reuptake glutamate following ammonia exposure may result in compromised neuron-astrocyte trafficking of glutamate and could thus contribute to the pathogenesis of the cerebral dysfunction characteristic of hyperammonemic syndromes such as hepatic encephalopathy.

Effect of portacaval anastomosis on glutamine synthetase protein and gene expression in brain, liver and skeletal muscle

The effects of chronic liver insufficiency resulting from end-to-side portacaval anastomosis (PCA) on glutamine synthetase (GS) activities, protein and gene expression were studied in brain, liver and skeletal muscle of male adult rats. Four weeks following PCA, activities of GS in cerebral cortex and cerebellum were reduced by 32% and 37% (p<0.05) respectively whereas GS activities in muscle were increased by 52% (p<0.05). GS activities in liver were decreased by up to 90% (p<0.01), a finding which undoubtedly reflects the loss of GS-rich perivenous hepatocytes following portal-systemic shunting. Immunoblotting techniques revealed no change in GS protein content of brain regions or muscle but a significant loss in liver of PCA rats. GS mRNA determined by semi-quantitative RT-PCR was also significantly decreased in the livers of PCA rats compared to sham-operated controls. These findings demonstrate that PCA results in a loss of GS gene expression in the liver and that brain does not show a compensatory induction of enzyme activity, rendering it particularly sensitive to increases in ammonia in chronic liver failure. The finding of a post-translational increase of GS in muscle following portacaval shunting suggests that, in chronic liver failure, muscle becomes the major organ responsible for the removal of excess blood-borne ammonia.

Increased "peripheral-type" benzodiazepine receptor sites and mRNA in thalamus of thiamine-deficient rats

"Peripheral-type" benzodiazepine receptors (PTBRs) are highly expressed on the outer mitochondrial membrane of several types of glial cells. In order to further elucidate the nature of the early glial cell changes in thiamine deficiency, PTBR sites and PTBR mRNA were measured in thalamus, a brain structure which is particularly vulnerable to thiamine deficiency, of thiamine-deficient rats at presymptomatic and symptomatic stages of deficiency. PTBR sites were measured using an in vitro binding technique and the selective radio ligand [3H]-PK11195. PTBR gene expression was measured by RT-PCR using oligonucleotide primers based upon the published sequence of the cloned rat PTBR. Microglial and astrocytic changes in thalamus due to thiamine deficiency were assessed using immunohistochemistry and antibodies to specific microglial (ED-1) and astrocytic (GFAP) proteins respectively. Significant increases of [3H]-PK11195 binding sites and concomitantly increased PTBR mRNA were observed in thalamus at the symptomatic stage of thiamine deficiency, coincident with severe neuronal cell loss and increased GFAP-immunolabelling (indicative of reactive gliosis). Positron Emission Tomography using 11C-PK11195 could provide a novel approach to the diagnosis and assessment of the extent of thalamic damage due to thiamine deficiency in humans with Wernicke's Encephalopathy.

Portacaval anastomosis causes selective alterations of peripheral-type benzodiazepine receptor expression in rat brain and peripheral tissues

There is a growing body of evidence to suggest that peripheral-type benzodiazepine receptors (PTBRs) and their endogenous ligands are implicated in the pathogenesis of end-organ failure in chronic liver disease. Portal-systemic encephalopathy, a major neuropsychiatric complication associated with chronic liver disease, results in activation of brain PTBR and probably in peripheral organs. In order to address these issues, PTBR mRNA was measured using semi-quantitative RT-PCR in extracts of cerebral cortex, kidney and testis of rats four weeks after end-to-side portacaval anastomosis and sham-operation (controls). Densities of PTBR sites were measured concomitantly by in vitro receptor binding using the selective PTBR ligand [3H]PK11195. Portacaval shunting resulted in a 2 to 3-fold increase in expression of PTBR in brain and kidney and a 37% reduction in expression in testis. Densities of [3H]PK11195 sites changed in parallel with the alterations of gene expression. These findings suggest that selective alterations of PTBR expression are implicated in the pathogenesis of peripheral tissue hypertrophy (kidney) and/or atrophy (testis) which accompanies portal-systemic shunting in chronic liver failure. In brain, activation of PTBR could result in an increase in the production of neurosteroids with potent inhibitory action in the CNS, which could contribute to the pathogenesis of portal-systemic encephalopathy.

Chronic exposure of rat primary astrocyte cultures to manganese results in increased binding sites for the 'peripheral-type' benzodiazepine receptor ligand 3H-PK 11195

Alterations of 'peripheral-type' benzodiazepine receptors (PTBRs) in brain are a feature of hepatic encephalopathy (HE). Although ammonia toxicity has been implicated in the disorder, recent findings suggest an accumulation of manganese in the brains of cirrhotic patients dying in hepatic coma. In this study, we examined the expression of PTBRs as well as the binding of the selective PTBR ligand 3H-PK 11195 in cultured astrocytes following chronic exposure to manganese. When astrocytes were exposed to 100 microM manganese for 1 week, a 57% increase in Bmax for 3H-PK 11195 binding was detected (P < 0.01) with no change in the Kd value. However, an examination by RT-PCR of the expression of the isoquinoline-binding moiety of the PTBR complex in these cells revealed no change in PTBR mRNA levels following manganese treatment. These findings suggest that manganese up-regulates 3H-PK 11195 binding sites by a process which does not involve a change in transcription. In view of the proposed role of astrocytic PTBRs in 'neurosteroid' synthesis, manganese-induced increases of PTBRs could contribute to the pathogenesis of HE.

Toward a better prescription of the prone back extension exercise to strengthen the back muscles

This study investigated the level of resistance and the level of muscle activation of the prone back exercise. Fifteen male subjects with no previous history of low back injury performed two repetitions of seven exercises. These consisted of four maximal isometric voluntary contractions (MVC) and three prone back extension (PBE) exercises. The subject was lying prone on a table, the upper body was suspended off the end of the table and the legs and thighs were secured to the table with straps. Three starting positions from the horizontal were investigated, 0 degree, 30 degrees and 60 degrees, and were compared with MVC to quantify the level of effort needed to perform the task. The results showed that the three PBE exercises require a level of resistance and a level of muscle activation generally under 40% of the maximum capacity of healthy subjects. Muscle activity of the erector spinae (ES) was slightly greater when the exercise started at 60 degrees, compared to 0 degree and 30 degrees. During the static phase of the PBE exercises, the level of resistance remained at 40% relative to the peak reaction moment of the MVC, but muscular activity of ES tended to work at a lower activity level. In conclusion, since for healthy subjects PBE exercises are low resistance exercises, they seem to be more specifically designed to develop muscular endurance of the back muscles.

Increased expression of glyceraldehyde-3-phosphate dehydrogenase in cultured astrocytes following exposure to manganese

Manganism is a disorder characterized by hyperintensities in basal ganglia structures on magnetic resonance imaging which may be the consequence of manganese deposition in these areas. Since manganese is taken up avidly into astrocytes and is known to interfere with cerebral energy metabolism, we studied the effect of this metal on the expression and activity of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in primary cultures of astrocytes. Treatment with 100 microM manganese for 7 days increased both the Vmax and Km values for GAPDH which was not reproducible with other divalent metals. Using RT-PCR, increased GAPDH expression was detected in cells exposed to manganese compared with controls. No changes in cytochrome oxidase activity or ATP levels were observed, and lactate production was unaffected, in manganese-treated cells. These findings provide evidence of a possible role for GAPDH in the mediation of the effects of manganese on central nervous system function.

[Seroprevalence of hepatitis B and C viruses in a psychiatric institution]

Many patients admitted to psychiatric institutions have a history of risk factors for contamination with the hepatitis B and C viruses (HBV and HCV). Immunization policies for psychiatric institution patients are not widely know. A study conducted in a 600-bed psychiatric institution in Paris, France, to evaluate the proportion of potentially contaminating patients at admission, as well as immunization use in HBV-negative patients. Serologic markers for the HBV and HCV were looked for prospectively in all patients admitted over a two-month period. Immunization use was evaluated in the patients who had a first serologic test in 1995 or 1996 and follow-up tests until the end of 1997. The prospective part of the study demonstrated preadmission exposure to the HBV in 23.0 +/- 6.0% of patients. This proportion was larger in men (26.0%) than in women (14.8%), although the difference was not statistically significant (P = 0.10). Four patients (2.0%) tested positive for the HbS Ag. Among the HBV-negative patients, 13.0% received the vaccine; all had protective antibody levels. These patients were younger and more likely to be first-time admissions (18.4% vs 3.6%, P < 0.01). HCV seroprevalence was 6.0%. Serologic tests for the HBV were requested for 327 patients between January 1995 and december 1996. Among the patients who were seronegative at admission and received follow-up at the study hospital, only 13.8% were immunized at this hospital. Of the HCV-positive subjects, 63.3% were also HBV-positive. None of the HCV-positive HBV-negative subjects received immunization subsequently. Six to eight per cent of patients admitted to the study hospital are potentially contaminating for the HBV or HCV. The level of hepatitis B vaccine use is too low, particularly in high-risk patients. These data indicate a need for policies aimed at effectively preventing HBV and HCV transmission (information, education, immunization campaigns), both during the psychiatric institution stay and after discharge.

Alcohol preference in AXB/BXA recombinant inbred mice: gender differences and gender-specific quantitative trait loci

The purpose of the present study was to characterize the C57BL/6J, A/J, and AXB/BXA Recombinant Inbred (RI) strains of mice for voluntary alcohol consumption. Quantitative Trait Locus (QTL) analysis was used to provide provisional location of QTLs for alcohol consumption. The inbred strains were screened for levels of alcohol intake (calculated as alcohol preference and absolute alcohol consumption) by receiving 4 days of forced exposure to a 10% (wt/vol) solution of alcohol, followed by 3 weeks of free choice between water and 10% alcohol. A wide and continuous distribution of values for alcohol consumption and preference was obtained in the AXB/BXA RI strains, confirming polygenic influences on alcohol-related behaviors. Significant gender differences were found for both alcohol preference [F28,651 = 2.12, p < 0.001] and absolute alcohol consumption [F28,647 = 2.57, p < 0.001]. In males, putative QTLs were mapped to chromosomes (Chrs) 2, 5, 7, 10, 11, and 16. Multiple regression analysis indicated that approximately 75% of the genetic variance in alcohol preference in males could be accounted for by three of the QTL regions. Several of the putative QTLs appeared to be male-specific (Tyr on Chr 7; D10Mit126 on Chr 10; D11Mit61 on Chr 11). In females, seven putative QTLs were mapped to Chrs 2, 4, 5, 7, 11, 16, and 19. Approximately 90% of the genetic variance in alcohol preference in females could be accounted for by four QTL regions, as determined by multiple regression. The QTL on Chr 11 near D11Mit35 appeared to be female-specific. This site was close to a female-specific QTL (Alcp2) previously mapped in C57BL/6J x DBA/2J backcrosses by Melo and coworkers (Nat Genet 13, 147, 1996). The QTLs mapped for alcohol preference in the present study must be considered suggestive at the present time, since only D2Mit74 met very strict statistical criteria for significance. However, the concordance across several studies for the loci on Chrs 2, 4, 7, 9, and 11 suggest that some common QTLs influencing alcohol preference have been identified. Confirmation of QTLs mapped in the present study is currently being conducted in a new series of recombinant congenic (RC) strains developed from reciprocal backcrosses between the A/J and C57BL/6J progenitors. The concomitant use of both RI and RC strains developed from the same progenitors should provide a powerful means of detecting, confirming, and mapping QTLs for alcohol-related traits.

Expression of ced-3 and ced-9 homologs in Alzheimer's disease cerebral cortex

In order to characterize cell death mechanisms involved in Alzheimer disease (AD), we quantitated the expression of ced-3 and ced-9 homologs in AD frontal cortex. Positive (ICE, ICErel-II, ICErel-III, Ich-1L, CPP32, mch2, mch3, bcl-xS, bax and bak) and negative (bcl-2, bcl-xL, MCL1 and Ich-1S) regulators of apoptosis were successively examined using a semi-quantitative technique of reverse transcription-polymerase chain reaction (RT-PCR). Total RNA was extracted from postmortem frontal cortex of AD patients (n = 7) and controls (n = 7) matched for age and autolysis time. Baseline levels of message were detected for 3 ced-3 (CPP32, Ich-1 and ICE) and 4 ced-9 homologs (bcl-x, MCL1, bcl-2 and bax) in the frontal cortex. There was an overexpression of the ICEalpha cDNA in AD patients as compared with age-matched controls (P = 0.03). Our results indicate that several ced-3 and ced-9 homologs are expressed in the adult human brain, and suggest that neuronal cell death in AD might involve an aberrant expression of ICEalpha.

Sensitivity analysis of segment models to estimate the net reaction moments at the L5/S1 joint in lifting

This paper deals with the mathematics of inverse dynamic analysis for calculating the net reaction moments; the sensitivity of the net reaction moments to nine experimental values is quantified and two dynamic models are compared. The results indicate that, among all terms, the external forces in the case of a lower body model and the segment masses in the case of an upper body model contributed the most to differences in the sensitivity of the lumbosacral reaction moment about the transverse axis. About the other axes there was no clear difference between the two body models.

Phylogenetic analysis of Escherichia coli strains causing neonatal meningitis suggests horizontal gene transfer from a predominant pool of highly virulent B2 group strains

Phylogenetic relationships of 69 neonatal meningitis Escherichia coli strains isolated worldwide were studied. Restriction fragment length polymorphism of rrn operons (rrn RFLP) in these isolates was compared with that of the 72 strains of the ECOR reference collection. Distributions of K1 antigen, of polymerase chain reaction-detected ibe10 gene, pap, afa, sfa/foc, hly, and aer operons, and of a 14.9-kb rrn-containing HindIII fragment previously associated with neonatal meningitis were compared. Oligoclonality was observed for the meningitis strains. Factorial analysis of correspondence on the rrn RFLP data showed a frequency gradient of meningitis strains from the phylogenetic B2 group (68%) to the A group (6%), via the D and B1 groups (26%). The distribution of the virulence determinants argues for their horizontal transfer during the evolution of E. coli. Analysis of the status of some neonates further suggests that neonatal meningitis results from a balance between bacterial genes of virulence and host factors.

Development and application of predictive equations of maximal static moments generated by the trunk musculature

OBJECTIVE: To develop and apply regression equations that predict the maximal static moments generated by the extensor, axial rotator and lateral flexor muscles of the trunk as a function of forward bending angles and asymmetrical positions of the torso in human subjects. DESIGN: Using experimental data, polynomial predictive equations were developed. The equations were applied in an algorithm to estimate the maximal moment generated by individual subjects. METHODS: Three groups of male subjects participated in the evaluation of the effect of forward bending and trunk asymmetry on the static moment of the extensor, right axial rotator, and right lateral flexor muscles of the trunk, respectively. Two other groups of male subjects were evaluated to test the validity of the algorithm. During the dynamometric tests, the three-dimensional position of the trunk was determined using cinematography techniques. RESULTS: For the extensor muscles, a curvilinear increase of the maximal moment was observed with forward bending, with a slight decrease of the moment on each side of the neutral position. For the right axial rotator muscles, both forward bending and left asymmetrical position of the trunk increased the maximal moments generated by these muscles. The right lateral flexors were stronger in the standing and mid-flexion positions than in other positions. First-order, second-order and interaction terms appear in the regression equations to account for the effect of forward bending and asymmetrical positions. The regression equation for the extensors and right axial rotator muscles have R(2) coefficients (range 0.56-0.76) higher than those of the lateral flexor regression equations (range 0.09-0.12). The algorithm results in an average error of 13% in predicting the strength of extensor and axial rotator muscles of individual subjects. CONCLUSION: The results have shown that strength of the extensor and axial rotator muscles is affected by forward bending and the asymmetry of the trunk, while strength of the lateral flexor muscles is only dependent on the forward bending position. The regression equations and the corresponding algorithm are applicable for the range of positions used in the study.

Increased expression of the peripheral-type benzodiazepine receptor-isoquinoline carboxamide binding protein mRNA in brain following portacaval anastomosis

Using RT-PCR, gene expression of the peripheral-type benzodiazepine receptor isoquinoline carboxamide-binding protein (PTBR-IBP) was studied in the frontal cortex of rats four weeks following end-to-side portacaval anastomosis, an experimental animal model of hepatic encephalopathy, or sham operation. Portacaval anastomosis resulted in increased expression of PTBR-IBP in frontal cortex and in a concomitant increase in densities (Bmax) of binding sites for the PTBR ligand [3H]PK11195. In view of the findings that the PTBR modulates the synthesis of neurosteroids with high affinity for excitatory and inhibitory neurotransmitter systems in brain, increased expression of these receptors could be implicated in the pathogenesis of hepatic encephalopathy.

Polyomavirus large T-antigen binds the "pRb related' protein p130 through sequences in conserved region 2

The transforming potential of DNA tumor viruses derives mainly from the ability of their encoded oncogene products to interact with cellular proteins. Many of these viral oncoproteins share regions of sequence similarity, designated conserved region 1 and 2, which have been implicated in complex formation with pRb, the product of the retinoblastoma tumor suppressor gene, and related p107 and p130 species. It has now been shown that the EIA protein of adenovirus is able to bind to all three pRb-related proteins through sequences in conserved region 1 and 2. We have shown previously that polyomavirus large T-antigen also interacts with pRb and p107 in vitro. The pRb and p107 binding domains reside between residues 141, 158 which include conserved region 2. In the present study, we demonstrate that polyomavirus large T-antigen also interacted with p130 in vitro through the same sequences in conserved region 2.

Functional implications of mutations within polyomavirus large T antigen Rb-binding domain: effects on pRb and p107 binding in vitro and immortalization activity in vivo

In this study, we have extensively modified the Rb-binding domain of polyomavirus large T antigen. Mutant polyomavirus large T antigens were tested for their ability to bind pRb and p107 in vitro and assayed for their capacity to immortalize primary rat embryo fibroblasts in vivo. Polyomavirus large T antigen bound pRb and p107 through a common region located between amino acids 141 to 158, containing the consensus Rb-binding sequence D/N-L-X-C-X-E. Substitution of any amino acid within the core Rb-binding sequence abolished pRb and p107 binding in vitro and immortalization activity in vivo. Substitution of amino acids outside the core Rb-binding sequence reduced pRb and p107 binding in vitro and decreased or abolished immortalization of rat embryo fibroblasts in vivo. Although duplication of the Rb-binding domain within the polyomavirus large T antigen results in a molecule that can bind at least twice as much pRb and p107 in vitro, this mutant displayed an essentially wild-type level of immortalization activity. More importantly, we found that the addition of acidic residues within the casein kinase II consensus phosphorylation region flanking the Rb-binding domain, or the deletion of amino acids 256 to 272, increased the immortalizing activity of the mutant polyomavirus large T antigen. These two mutants displayed a greater than wild-type level of pRb binding in vitro, while in contrast, a decreased affinity for p107 binding in vitro was observed. Together, these results indicate that while pRb binding appears to be an essential event for immortalization, there is no tight correlation between the frequency of immortalization and the absolute level of pRb binding in vitro, indicating that other large T antigen functions are important for cellular immortalization.