A randomized controlled clinical trial evaluating the performance and safety of platelets treated with MIRASOL pathogen reduction technology.

BACKGROUND: Pathogen reduction of platelets (PRT-PLTs) using riboflavin and ultraviolet light treatment has undergone Phase 1 and 2 studies examining efficacy and safety. This randomized controlled clinical trial (RCT) assessed the efficacy and safety of PRT-PLTs using the 1-hour corrected count increment (CCI(1hour) ) as the primary outcome. STUDY DESIGN AND METHODS: A noninferiority RCT was performed where patients with chemotherapy-induced thrombocytopenia (six centers) were randomly allocated to receive PRT-PLTs (Mirasol PRT, CaridianBCT Biotechnologies) or reference platelet (PLT) products. The treatment period was 28 days followed by a 28-day follow-up (safety) period. The primary outcome was the CCI(1hour) determined using up to the first eight on-protocol PLT transfusions given during the treatment period. RESULTS: A total of 118 patients were randomly assigned (60 to PRT-PLTs; 58 to reference). Four patients per group did not require PLT transfusions leaving 110 patients in the analysis (56 PRT-PLTs; 54 reference). A total of 541 on-protocol PLT transfusions were given (303 PRT-PLTs; 238 reference). The least square mean CCI was 11,725 (standard error [SE], 1.140) for PRT-PLTs and 16,939 (SE, 1.149) for the reference group (difference, -5214; 95% confidence interval, -7542 to -2887; p<0.0001 for a test of the null hypothesis of no difference between the two groups). CONCLUSION: The study failed to show noninferiority of PRT-PLTs based on predefined CCI criteria. PLT and red blood cell utilization in the two groups was not significantly different suggesting that the slightly lower CCIs (PRT-PLTs) did not increase blood product utilization. Safety data showed similar findings in the two groups. Further studies are required to determine if the lower CCI observed with PRT-PLTs translates into an increased risk of bleeding.

Increasing lactate turnover rate during exercise by means of altitude training and fructose ingestion : effects on substrate metabolism and endurance performance

Summary : With regard to exercise metabolism, lactate was long considered as a dead-end waste product responsible for muscle fatigue and a limiting factor for motor performance. However, a large body of evidence clearly indicates that lactate is an energy efficient metabolite able to link the glycolytic pathway with aerobic metabolism and has endocrine-like actions, rather than to be a dead-end waste product. Lactate metabolism is also known to be quickly upregulated by regular endurance training and is thought to be related to exercise performance. However, to what extent its modulation can increase exercise performance in already endurance-trained subjects is unknown. The general hypothesis of this work was therefore that increasing either lactate metabolic clearance rate or lactate availability could, in turn, increase endurance performance. The first study (Study I) aimed at increasing the lactate clearance rate by means of assumed interaction effects of endurance training and hypoxia on lactate metabolism and endurance performance. Although this study did not demonstrate any interaction of training and hypoxia on both lactate metabolism and endurance performance, a significant deleterious effect of endurance training in hypoxia was shown on glucose homeostasis. The methods used to determine lactate kinetics during exercise exhibited some limitations, and the second study did delineate some of the issues raised (Study 2). The third study (Study 3) investigated the metabolic and performance effects of increasing plasma lactate production and availability during prolonged exercise in the fed state. A nutritional intervention was used for this purpose: part of glucose feedings ingested during the control condition was substituted by fructose. The results of this study showed a significant increase of lactate turnover rate, quantified the metabolic fate of fructose; and demonstrated a significant decrease of lipid oxidation and glycogen breakdown. In contrast, endurance performance appeared to be unmodified by this dietary intervention, being at odds with recent reports. Altogether the results of this thesis suggest that in endurance athletes the relationship between endurance performance and lactate turnover rate remains unclear. Nonetheless, the result of the present study raises questions and opens perspectives on the rationale of using hypoxia as a therapeutic aid for the treatment of insulin resistance. Moreover, the results of the second study open perspectives on the role of lactate as an intermediate metabolite and its modulatory effects on substrate metabolism during exercise. Additionally it is suggested that the simple nutritional intervention used in the third study can be of interest in the investigation on the aforementioned roles of lactate. Résumé : Lorsque le lactate est évoqué en rapport avec l'exercice, il est souvent considéré comme un déchet métabolique responsable de l'acidose métabolique, de la fatigue musculaire ou encore comme un facteur limitant de la performance. Or la littérature montre clairement que le lactate se révèle être plutôt un métabolite utilisé efficacement par de nombreux tissus par les voies oxydatives et, ainsi, il peut être considéré comme un lien entre le métabolisme glycolytique et le métabolisme oxydatif. De plus on lui prête des propriétés endocrines. Il est connu que l'entraînement d'endurance accroît rapidement le métabolisme du lactate, et il est suggéré que la performance d'endurance est liée à son métabolisme. Toutefois la relation entre le taux de renouvellement du lactate et la performance d'endurance est peu claire, et, de même, de quelle manière la modulation de son métabolisme peut influencer cette dernière. Le but de cette thèse était en conséquence d'investiguer de quelle manière et à quel degré l'augmentation du métabolisme du lactate, par l'augmentation de sa clearance et de son turnover, pouvait à son tour améliorer la performance d'endurance de sujets entraînés. L'objectif de la première étude a été d'augmenter la clearance du lactate par le biais d'un entraînement en conditions hypoxiques chez des cyclistes d'endurance. Basé sur la littérature scientifique existante, on a fait l'hypothèse que l'entraînement d'endurance et l'hypoxie exerceraient un effet synergétique sur le métabolisme du lactate et sur la performance, ce qui permettrait de montrer des relations entre performance et métabolisme du lactate. Les résultats de cette étude n'ont montré aucun effet synergique sur la performance ou le métabolisme du lactate. Toutefois, un effet délétère sur le métabolisme du glucose a été démontré. Quelques limitations de la méthode employée pour la mesure du métabolisme du lactate ont été soulevées, et partiellement résolues dans la seconde étude de ce travail, qui avait pour but d'évaluer la sensibilité du modèle pharmacodynamique utilisé pour le calcul du turnover du lactate. La troisième étude a investigué l'effet d'une augmentation de la lactatémie sur le métabolisme des substrats et sur la performance par une intervention nutritionnelle substituant une partie de glucose ingéré pendant l'exercice par du fructose. Les résultats montrent que les composants dynamiques du métabolisme du lactate sont significativement augmentés en présence de fructose, et que les oxydations de graisse et de glycogène sont significativement diminuées. Toutefois aucun effet sur la performance n'a été démontré. Les résultats de ces études montrent que la relation entre le métabolisme du lactate et la performance reste peu claire. Les résultats délétères de la première étude laissent envisager des pistes de travail, étant donné que l'entraînement en hypoxie est considéré comme outil thérapeutique dans le traitement de pathologies liées à la résistance à l'insuline. De plus les résultats de la troisième étude ouvrent des perspectives de travail quant au rôle du lactate comme intermédiaire métabolique durant l'exercice ainsi que sur ses effets directs sur le métabolisme. Ils suggèrent de plus que la manipulation nutritionnelle simple qui a été utilisée se révèle être un outil prometteur dans l'étude des rôles et effets métaboliques que peut revêtir le lactate durant l'exercice.

Lactate and the injured brain: friend or foe?

PURPOSE OF REVIEW: Energy metabolism is increasingly recognized as a key factor in the pathogenesis of acute brain injury (ABI). We review the role of cerebral lactate metabolism and summarize evidence showing that lactate may act as supplemental fuel after ABI. RECENT FINDINGS: The role of cerebral lactate has shifted from a waste product to a potentially preferential fuel and signaling molecule. According to the astrocyte-neuron lactate shuttle model, glycolytic lactate might act as glucose-sparing substrate. Lactate also is emerging as a key signal to regulate cerebral blood flow (CBF) and a neuroprotective agent after experimental ABI. Clinical investigation using cerebral microdialysis shows the existence of two main lactate patterns, ischemic - from anaerobic metabolism - and nonischemic, from activated glycolysis, whereby lactate can be used as supplemental energy fuel. Preliminary clinical data suggests hypertonic lactate solutions improve cerebral energy metabolism and are an effective treatment for elevated intracranial pressure (ICP) after ABI. SUMMARY: Lactate can be a supplemental fuel for the injured brain and is important to regulate glucose metabolism and CBF. Exogenous lactate supplementation may be neuroprotective after experimental ABI. Recent clinical data from ABI patients suggest hypertonic lactate solutions may be a valid therapeutic option for secondary energy dysfunction and elevated ICP.

Dietary supplements utilization: an explanatory survey among Swiss consumers

Dietary supplement (DS) use increased rapidly over the last years. However evidence of benefits of many DS for healthy users are scarce and may not equate known risks of overdose, drug interaction and recently discovered negative long-term effects. Therefore this study aimed to investigate perceptions and motivations of DS users in Lausanne, Switzerland. Method A convenience sample was recruited at the entrance of local sales points. Data were collected in on-site semi-structured interviews to assess dietary supplementation habits. Results The 119 participants provided information on 147 users. Among 273 declared products, the majority were mixed products, containing minerals and vitamins (78), mineral products (69), and herbal products (28). 55% of DS users took more than one product simultaneously. Seventy five percent of participants indicated that DS use presents no risk or nearly no risk and about half (49%) of participants did not inform their physician about their consumption. Male participants reported to share this information with their physicians significantly less frequently than female participants (p = 0.008). About half of participants looked for information on potential risks of DS, men significantly more often than women (p=0.001). Discussion According to other studies in the US, our study shows that, in Lausanne (Switzerland), DS are commonly used as mixed products. Risk perception seems generally low among DS users. Implications Physicians should be trained to evaluate patientsʼ health behaviour and needs in order to provide good evidence based information or propose alternatives to DS use.

La dépendance à l'égard de l'environnement lors de lésions cérébrales: conduites d'imitation, de préhension et d'utilisation [Environmental dependence in brain lesions: imitative behavior, prehension and utilization].

This paper reviews the literature on clinical signs such as imitation behavior, grasp reaction, manipulation of tools, utilization behavior, environmental dependency, hyperlexia, hypergraphia and echolalia. Some aspects of this semiology are of special interest because they refer to essential notions such as free-will and autonomy.

Effects of infused amino acids on glucose production and utilization in healthy human subjects.

Amino acids have been reported to increase endogenous glucose production in normal human subjects during hyperinsulinemia: however, controversy exists as to whether insulin-mediated glucose disposal is inhibited under these conditions. The effect of an amino acid infusion on glucose oxidation rate has so far not been determined. Substrate oxidation rates, endogenous glucose production, and [13C]glucose synthesis from [13C]bicarbonate were measured in six normal human subjects during sequential infusions of exogenous glucose and exogenous glucose with (n = 5) or without (n = 5) exogenous amino acids. Amino acids increased endogenous glucose production by 84% and [13C]glucose synthesis by 235%. Glucose oxidation estimated from indirect calorimetry decreased slightly after amino acids, but glucose oxidation estimated from [13C]glucose-13CO2 data was increased by 14%. It is concluded that gluconeogenesis is the major pathway of amino acid degradation. During amino acid administration, indirect calorimetry underestimates the true rate of glucose oxidation, whereas glucose oxidation calculated from the 13C enrichment of expired CO2 during [U-13C]glucose infusion does not. A slight stimulation of glucose oxidation during amino acid infusion, concomitant with an increased plasma insulin concentration, indicates that amino acids do not inhibit glucose oxidation.

Identification of case complexity and increased health care utilization in patients with rheumatoid arthritis.

OBJECTIVES: To document biopsychosocial profiles of patients with rheumatoid arthritis (RA) by means of the INTERMED and to correlate the results with conventional methods of disease assessment and health care utilization. METHODS: Patients with RA (n = 75) were evaluated with the INTERMED, an instrument for assessing case complexity and care needs. Based on their INTERMED scores, patients were compared with regard to severity of illness, functional status, and health care utilization. RESULTS: In cluster analysis, a 2-cluster solution emerged, with about half of the patients characterized as complex. Complex patients scoring especially high in the psychosocial domain of the INTERMED were disabled significantly more often and took more psychotropic drugs. Although the 2 patient groups did not differ in severity of illness and functional status, complex patients rated their illness as more severe on subjective measures and on most items of the Medical Outcomes Study Short Form 36. Complex patients showed increased health care utilization despite a similar biologic profile. CONCLUSIONS: The INTERMED identified complex patients with increased health care utilization, provided meaningful and comprehensive patient information, and proved to be easy to implement and advantageous compared with conventional methods of disease assessment. Intervention studies will have to demonstrate whether management strategies based on INTERMED profiles can improve treatment response and outcome of complex patients.

Separate neuronal and glial Na+,K+-ATPase isoforms regulate glucose utilization in response to membrane depolarization and elevated extracellular potassium.

The role of cell type-specific Na+,K+-ATPase isozymes in function-related glucose metabolism was studied using differentiated rat brain cell aggregate cultures. In mixed neuron-glia cultures, glucose utilization, determined by measuring the rate of radiolabeled 2-deoxyglucose accumulation, was markedly stimulated by the voltage-dependent sodium channel agonist veratridine (0.75 micromol/L), as well as by glutamate (100 micromol/L) and the ionotropic glutamate receptor agonist N-methyl-D-aspartate (NMDA) (10 micromol/L). Significant stimulation also was elicited by elevated extracellular potassium (12 mmol/L KCl), which was even more pronounced at 30 mmol/L KCl. In neuron-enriched cultures, a similar stimulation of glucose utilization was obtained with veratridine, specific ionotropic glutamate receptor agonists, and 30 mmol/L but not 12 mmol/L KCl. The effects of veratridine, glutamate, and NMDA were blocked by specific antagonists (tetrodotoxin, CNQX, or MK801, respectively). Low concentrations of ouabain (10(-6) mol/L) prevented stimulation by the depolarizing agents but reduced only partially the response to 12 mmol/L KCl. Together with previous data showing cell type-specific expression of Na+,K+-ATPase subunit isoforms in these cultures, the current results support the view that distinct isoforms of Na+,K+-ATPase regulate glucose utilization in neurons in response to membrane depolarization, and in glial cells in response to elevated extracellular potassium.

On problems of calculating energy expenditure and substrate utilization from respiratory exchange data.

Indirect calorimetry based on respiratory exchange measurement has been successfully used from the beginning of the century to obtain an estimate of heat production (energy expenditure) in human subjects and animals. The errors inherent to this classical technique can stem from various sources: 1) model of calculation and assumptions, 2) calorimetric factors used, 3) technical factors and 4) human factors. The physiological and biochemical factors influencing the interpretation of calorimetric data include a change in the size of the bicarbonate and urea pools and the accumulation or loss (via breath, urine or sweat) of intermediary metabolites (gluconeogenesis, ketogenesis). More recently, respiratory gas exchange data have been used to estimate substrate utilization rates in various physiological and metabolic situations (fasting, post-prandial state, etc.). It should be recalled that indirect calorimetry provides an index of overall substrate disappearance rates. This is incorrectly assumed to be equivalent to substrate "oxidation" rates. Unfortunately, there is no adequate golden standard to validate whole body substrate "oxidation" rates, and this contrasts to the "validation" of heat production by indirect calorimetry, through use of direct calorimetry under strict thermal equilibrium conditions. Tracer techniques using stable (or radioactive) isotopes, represent an independent way of assessing substrate utilization rates. When carbohydrate metabolism is measured with both techniques, indirect calorimetry generally provides consistent glucose "oxidation" rates as compared to isotopic tracers, but only when certain metabolic processes (such as gluconeogenesis and lipogenesis) are minimal or / and when the respiratory quotients are not at the extreme of the physiological range. However, it is believed that the tracer techniques underestimate true glucose "oxidation" rates due to the failure to account for glycogenolysis in the tissue storing glucose, since this escapes the systemic circulation. A major advantage of isotopic techniques is that they are able to estimate (given certain assumptions) various metabolic processes (such as gluconeogenesis) in a noninvasive way. Furthermore when, in addition to the 3 macronutrients, a fourth substrate is administered (such as ethanol), isotopic quantification of substrate "oxidation" allows one to eliminate the inherent assumptions made by indirect calorimetry. In conclusion, isotopic tracers techniques and indirect calorimetry should be considered as complementary techniques, in particular since the tracer techniques require the measurement of carbon dioxide production obtained by indirect calorimetry. However, it should be kept in mind that the assessment of substrate oxidation by indirect calorimetry may involve large errors in particular over a short period of time. By indirect calorimetry, energy expenditure (heat production) is calculated with substantially less error than substrate oxidation rates.

Health services utilization associated with cognitive impairment and dementia in older patients undergoing post-acute rehabilitation.

OBJECTIVE: To investigate the relationship between levels of cognitive impairment and health services utilization in older patients undergoing post-acute rehabilitation. DESIGN: Cross-sectional study. SETTING: Post-acute rehabilitation facility. PARTICIPANTS: Patients (N = 1764) aged 70 years and older admitted over 3 years. MEASUREMENTS: Sociodemographic, medical, and functional data were collected upon admission. Based on discharge diagnoses, patients were classified as cognitively intact, cognitively impaired with no dementia (CIND), and demented. RESULTS: Dementia and CIND were diagnosed in 425 (24.1%) and 301 (17.1%) patients, respectively. Gradients from cognitively intact to cognitively impaired to demented patients were observed in median length of stay (19, 22, and 25 days, P < .001), and institutionalization rates at discharge (4.2%, 7.6%, and 28.8%, P < .001). Among patients discharged home, similar gradients were observed in utilization of home care (68.2%, 79.7%, and 83.3%, P < .001) and day care (3.1%, 7.1%, and 14.3%, P < .001). After adjustment, compared with cognitively intact patients, only those with dementia still had longer stays (+2.7 days) and increased odds of institutionalization (adjOR 6.1, 95% CI 4.0-9.3, P < .001). Among patients discharged home, use of home and day care remained higher in those with dementia (adjOR 1.8, 95% CI 1.2-2.7, P = .005, and adjOR 1.8, 95% CI 1.2-2.7, P = .005, respectively), while CIND patients had higher odds of using home care (adjOR 1.6, 95% CI 1.1-2.4, P = .028). CONCLUSION: Among patients undergoing post-acute rehabilitation, those with dementia had increased use of both institutional and community care, whereas those with CIND had increased use of home care services only. Future studies should investigate specific strategies susceptible to reduce the related burden on health care systems.

Off-label utilization of antipsychotics

Résumé Ce travail s'inscrit dans un programme de recherche centré sur la pharmacovigilance en psychiatrie. Buts de l'étude Les nouveaux antipsychotiques atypiques sont prescrits avec beaucoup de succès, parce qu'ils présentent une sécurité dans leur emploi bien supérieure à celle des antipsychotiques classiques. Cette situation a conduit à une large prescription «off-label» (hors indication admise). Le but de ce travail a été d'étudier la pratique en matière de prescription des psychiatres hospitaliers en ce qui concerne les antipsychotiques en comparant des patients traités pour des psychoses ou d'autres indications officielles aux patients recevant un traitement antipsychotique «off-label». Méthode Dans le cadre d'un programme de pharmacovigilance - pharmacoépidemiologie, tous les médicaments prescrits à 5 jours de référence (entre 1999 et 2001) à l'hôpital psychiatrique universitaire de Lausanne (98 lits) ont été enregistrés, avec des données sur l'âge, le sexe et le diagnostic des patients. Les prescriptions de 202 patients ont été évaluées. Les patients ont été classés dans 3 groupes diagnostiques : (1) patient présentant des troubles psychotiques, (2) patient présentant des épisodes maniaques et des épisodes dépressifs avec des symptômes psychotiques, et (3) patient présentant d'autres troubles. Les groupes (1) et (2) forment une classe de patients recevant un antipsychotique pour une indication officielle, et les prescriptions dans le groupe (3) ont été considérées comme «off-label». Résultats principaux Moins de patients psychotiques ont reçu un antidépresseur (p<0.05) ou des hypnotiques non-benzodiazepine (p<0.001) comparés aux patients des deux autres groupes. Les patients présentant des troubles affectifs recevaient seulement exceptionnellement une combinaison d'un antipsychotique atypique et conventionnel, tandis qu'un nombre inférieur de patients avec des indications « off-label » ont reçu moins .souvent des antipsychotiques atypiques que ceux des deux groupes de comparaison (p<0.05). L'analyse statistique (stepwise logistic regression) a révélé que les patients présentant des troubles psychotiques avaient un risque plus élevé de recevoir un médicament antipsychotique d'une dose moyenne ou élevée, (p<0.001) en comparaison aux deux autres groupes. Conclusion Les nouveaux médicaments antipsychotiques semblent être prescrits avec moins d'hésitation principalement pour des indications admises. Les médecins prescrivent de nouveaux médicaments « off-label » seulement après avoir acquis une certaine expérience dans le domaine des indications approuvées, et ils étaient plus prudents en ce qui concerne la dose en traitant sur la base «off-label». Abstract Objective The new brands of atypical antipsychotics are very successfully prescribed because of their enhanced safety profiles and their larger pharmacological profile in comparison to the conventional antipsychotic. This has led to broad off-label utilisation. The aim of the present survey was to study the prescription practice of hospital psychiatrists with regard to antipsychotic drugs, comparing patients treated for psychoses or other registered indications to patients receiving an off-label antipsychotic treatment. Method As part of a pharmacovigilance/pharmacoepidemiology program, all drugs given on 5 reference days (1999 - 2001) in the 98-bed psychiatric hospital of the University of Lausanne, Switzerland, were recorded along with age, sex and diagnosis. The prescriptions of 202 patients were assessed. Patients were classified in 3 diagnostic groups: (1) patient with psychotic disorders, (2) patients with manic episodes and depressive episodes with psychotic symptoms, and (3) patients with other disorders. Group (1) and (2) formed the class of patients receiving an antipsychotic for a registered indication, and the prescriptions in group (3) were considered as off-label. Main results A lesser number of psychotic patients received antidepressant (p<0.05) and nonbenzodiazepine hypnotics (p<0.001) compared to the patients of the other two groups. The patients with affective disorders received only exceptionally a combination of an atypical and a conventional antipsychotic, whereas a lesser number of patients with off-label indications received less often atypical antipsychotics than those of the two comparison groups (p<0.05). Stepwise logistic regression revealed that patients with psychotic disorder were at higher risk of receiving an antipsychotic medication in medium or high dose (p<0.001), in comparison to the two other groups. Conclusions The new antipsychotic drugs seem to be prescribed with less hesitation mainly for approved indications. Physicians prescribe new drugs on off-label application only after having gained some experience in the field of the approved indications, and were more cautious with regard to dose when treating on an off-label basis.