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1.
Cochrane Database Syst Rev ; 9: CD015519, 2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39229865

RESUMEN

BACKGROUND: With prevalence estimates between 50% and 90% of people with cancer, cancer-related fatigue is one of the most common morbidities related to cancer and its treatment. Exercise is beneficial for the treatment of cancer-related fatigue. However, the efficacy of different types of exercise (i.e. cardiovascular training and resistance training) have not yet been investigated systematically and compared directly in a meta-analysis. OBJECTIVES: To compare the benefits and harms of cardiovascular training versus resistance training for treatment or prevention of cancer-related fatigue in people with cancer. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, and five other databases in January 2023. We searched ClinicalTrials.gov and the International Clinical Trials Registry Platform for ongoing trials. We integrated results from update searches of previously published Cochrane reviews. In total, our searches included trials from inception to October 2023. SELECTION CRITERIA: We included randomised controlled trials investigating cardiovascular training compared with resistance training, with exercise as the main component. We included studies on adults with cancer (aged 18 years and older), with or without a diagnosis of cancer-related fatigue, for any type of cancer and any type of cancer treatment, with the intervention starting before, during, or after treatment. We included trials evaluating at least one of our primary outcomes (cancer-related fatigue or quality of life). We excluded combined cardiovascular and resistance interventions, yoga, and mindfulness-based interventions. Our primary outcomes were cancer-related fatigue and quality of life. Our secondary outcomes were adverse events, anxiety, and depression. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology. For analyses, we pooled results within the same period of outcome assessment (i.e. short term (up to and including 12 weeks' follow-up), medium term (more than 12 weeks' to less than six months' follow-up), and long term (six months' follow-up or longer)). We assessed risk of bias using the Cochrane RoB 1 tool, and certainty of the evidence using GRADE. MAIN RESULTS: We included six studies with 447 participants with prostate, breast, or lung cancer who received radiotherapy or chemotherapy, had surgery, or a combination of these. All studies had a high risk of bias due to lack of blinding. Three studies had an additional high risk of bias domain; one study for attrition bias, and two studies for selection bias. Interventions in the cardiovascular training groups included training on a cycle ergometer, treadmill, an elliptical trainer, or indoor bike. Interventions in the resistance training group included a varying number of exercises using bodyweight, weights, or resistance bands. Interventions varied in frequency, intensity, and duration. None of the included studies reported including participants with a confirmed cancer-related fatigue diagnosis. The interventions in four studies started during cancer treatment and in two studies after cancer treatment. Before treatment No studies reported interventions starting before cancer treatment. During treatment The evidence was very uncertain about the effect of cardiovascular training compared with resistance training for short-term cancer-related fatigue (mean difference (MD) -0.29, 95% confidence interval (CI) -2.52 to 1.84; 4 studies, 311 participants; Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-Fatigue) scale where higher values indicate better outcome; very low-certainty evidence) and long-term cancer-related fatigue (MD 1.30, 95% CI -2.17 to 4.77; 1 study, 141 participants; FACIT-Fatigue scale; very low-certainty evidence). The evidence was very uncertain about the effect of cardiovascular training compared with resistance training for short-term quality of life (MD 1.47, 95% CI -1.47 to 4.42; 4 studies, 319 participants; Functional Assessment of Cancer Therapy - General scale where higher values indicate better outcome; very low-certainty evidence) and for long-term quality of life (MD 3.40, 95% CI -4.85 to 11.65; 1 study, 141 participants; Functional Assessment of Cancer Therapy - Anemia scale where higher values indicate better outcome; very low-certainty evidence). The evidence is very uncertain about the effect of cardiovascular training compared with resistance training on the occurrence of adverse events at any follow-up (risk ratio (RR) 2.00, 95% CI 0.19 to 21.18; 2 studies, 128 participants; very low-certainty evidence). No studies reported medium-term cancer-related fatigue or quality of life. After treatment The evidence was very uncertain about the effect of cardiovascular training compared with resistance training for short-term cancer-related fatigue (MD 1.47, 95% CI -0.09 to 3.03; 1 study, 95 participants; Multidimensional Fatigue Inventory-20 General Fatigue subscale where higher values indicate worse outcome; very low-certainty evidence). Resistance training may improve short-term quality of life compared to cardiovascular training, but the evidence is very uncertain (MD -10.96, 95% CI -17.77 to -4.15; 1 study, 95 participants; European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 Global Health subscale where higher values indicate better outcome; very low-certainty evidence). No studies reported outcomes at medium-term or long-term follow-up. AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effects of cardiovascular training compared with resistance training on treatment of cancer-related fatigue in people with cancer. Larger, well-conducted studies including people with different cancer types receiving different treatments are needed to increase the certainty in the evidence and to better understand who may benefit most from cardiovascular or resistance training. Moreover, studies comparing the effects of cardiovascular and resistance training initiated before as well as after cancer treatment are needed to understand the prophylactic and rehabilitative effects of these exercise types on cancer-related fatigue.


Asunto(s)
Sesgo , Fatiga , Neoplasias , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Entrenamiento de Fuerza , Humanos , Entrenamiento de Fuerza/métodos , Fatiga/etiología , Fatiga/terapia , Neoplasias/complicaciones , Masculino , Femenino , Depresión/terapia , Depresión/etiología , Ansiedad/terapia , Adulto
2.
Clin Pharmacokinet ; 2024 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-39153056

RESUMEN

INTRODUCTION: In the last decade, various Machine Learning techniques have been proposed aiming to individualise the dose of anticancer drugs mostly based on a presumed drug effect or measured effect biomarkers. The aim of this scoping review was to comprehensively summarise the research status on the use of Machine Learning for precision dosing in anticancer drug therapy. METHODS: This scoping review was conducted in accordance with the interim guidance by Cochrane and the Joanna Briggs Institute. We systematically searched the databases Medline (via PubMed), Embase and the Cochrane Library for research articles and reviews including results published after 2016. Results were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. RESULTS: A total of 17 relevant studies was identified. In 12 of the included studies, Reinforcement Learning methods were used, including Classical, Deep, Double Deep and Conservative Q-Learning and Fuzzy Reinforcement Learning. Furthermore, classical Machine Learning methods were compared in terms of their performance and an artificial intelligence platform based on parabolic equations was used to guide dosing prospectively and retrospectively, albeit only in a limited number of patients. Due to the significantly different algorithm structures, a meaningful comparison between the various Machine Learning approaches was not possible. CONCLUSION: Overall, this review emphasises the clinical relevance of Machine Learning methods for anticancer drug dose optimisation, as many algorithms have shown promising results enabling model-free predictions with the potential to maximise efficacy and minimise toxicity when compared to standard protocols.

3.
Cochrane Database Syst Rev ; 7: CD013451, 2024 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-38979716

RESUMEN

BACKGROUND: Bisphosphonates and receptor activator of nuclear factor-kappa B ligand (RANKL)-inhibitors are amongst the bone-modifying agents used as supportive treatment in women with breast cancer who do not have bone metastases. These agents aim to reduce bone loss and the risk of fractures. Bisphosphonates have demonstrated survival benefits, particularly in postmenopausal women. OBJECTIVES: To assess and compare the effects of different bone-modifying agents as supportive treatment to reduce bone mineral density loss and osteoporotic fractures in women with breast cancer without bone metastases and generate a ranking of treatment options using network meta-analyses (NMAs). SEARCH METHODS: We identified studies by electronically searching CENTRAL, MEDLINE and Embase until January 2023. We searched various trial registries and screened abstracts of conference proceedings and reference lists of identified trials. SELECTION CRITERIA: We included randomised controlled trials comparing different bisphosphonates and RANKL-inihibitors with each other or against no further treatment or placebo for women with breast cancer without bone metastases. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed the risk of bias of included studies and certainty of evidence using GRADE. Outcomes were bone mineral density, quality of life, overall fractures, overall survival and adverse events. We conducted NMAs and generated treatment rankings. MAIN RESULTS: Forty-seven trials (35,163 participants) fulfilled our inclusion criteria; 34 trials (33,793 participants) could be considered in the NMA (8 different treatment options). Bone mineral density We estimated that the bone mineral density of participants with no treatment/placebo measured as total T-score was -1.34. Evidence from the NMA (9 trials; 1166 participants) suggests that treatment with ibandronate (T-score -0.77; MD 0.57, 95% CI -0.05 to 1.19) may slightly increase bone mineral density (low certainty) and treatment with zoledronic acid (T-score -0.45; MD 0.89, 95% CI 0.62 to 1.16) probably slightly increases bone mineral density compared to no treatment/placebo (moderate certainty). Risedronate (T-score -1.08; MD 0.26, 95% CI -0.32 to 0.84) may result in little to no difference compared to no treatment/placebo (low certainty). We are uncertain whether alendronate (T-score 2.36; MD 3.70, 95% CI -2.01 to 9.41) increases bone mineral density compared to no treatment/placebo (very low certainty). Quality of life No quantitative analyses could be performed for quality of life, as only three studies reported this outcome. All three studies showed only minimal differences between the respective interventions examined. Overall fracture rate We estimated that 70 of 1000 participants with no treatment/placebo had fractures. Evidence from the NMA (16 trials; 19,492 participants) indicates that treatment with clodronate or ibandronate (42 of 1000; RR 0.60, 95% CI 0.39 to 0.92; 40 of 1000; RR 0.57, 95% CI 0.38 to 0.86, respectively) decreases the number of fractures compared to no treatment/placebo (high certainty). Denosumab or zoledronic acid (51 of 1000; RR 0.73, 95% CI 0.52 to 1.01; 55 of 1000; RR 0.79, 95% CI 0.56 to 1.11, respectively) probably slightly decreases the number of fractures; and risedronate (39 of 1000; RR 0.56, 95% CI 0.15 to 2.16) probably decreases the number of fractures compared to no treatment/placebo (moderate certainty). Pamidronate (106 of 1000; RR 1.52, 95% CI 0.75 to 3.06) probably increases the number of fractures compared to no treatment/placebo (moderate certainty). Overall survival We estimated that 920 of 1000 participants with no treatment/placebo survived overall. Evidence from the NMA (17 trials; 30,991 participants) suggests that clodronate (924 of 1000; HR 0.95, 95% CI 0.77 to 1.17), denosumab (927 of 1000; HR 0.91, 95% CI 0.69 to 1.21), ibandronate (915 of 1000; HR 1.06, 95% CI 0.83 to 1.34) and zoledronic acid (925 of 1000; HR 0.93, 95% CI 0.76 to 1.14) may result in little to no difference regarding overall survival compared to no treatment/placebo (low certainty). Additionally, we are uncertain whether pamidronate (905 of 1000; HR 1.20, 95% CI 0.81 to 1.78) decreases overall survival compared to no treatment/placebo (very low certainty). Osteonecrosis of the jaw We estimated that 1 of 1000 participants with no treatment/placebo developed osteonecrosis of the jaw. Evidence from the NMA (12 trials; 23,527 participants) suggests that denosumab (25 of 1000; RR 24.70, 95% CI 9.56 to 63.83), ibandronate (6 of 1000; RR 5.77, 95% CI 2.04 to 16.35) and zoledronic acid (9 of 1000; RR 9.41, 95% CI 3.54 to 24.99) probably increases the occurrence of osteonecrosis of the jaw compared to no treatment/placebo (moderate certainty). Additionally, clodronate (3 of 1000; RR 2.65, 95% CI 0.83 to 8.50) may increase the occurrence of osteonecrosis of the jaw compared to no treatment/placebo (low certainty). Renal impairment We estimated that 14 of 1000 participants with no treatment/placebo developed renal impairment. Evidence from the NMA (12 trials; 22,469 participants) suggests that ibandronate (28 of 1000; RR 1.98, 95% CI 1.01 to 3.88) probably increases the occurrence of renal impairment compared to no treatment/placebo (moderate certainty). Zoledronic acid (21 of 1000; RR 1.49, 95% CI 0.87 to 2.58) probably increases the occurrence of renal impairment while clodronate (12 of 1000; RR 0.88, 95% CI 0.55 to 1.39) and denosumab (11 of 1000; RR 0.80, 95% CI 0.54 to 1.19) probably results in little to no difference regarding the occurrence of renal impairment compared to no treatment/placebo (moderate certainty). AUTHORS' CONCLUSIONS: When considering bone-modifying agents for managing bone loss in women with early or locally advanced breast cancer, one has to balance between efficacy and safety. Our findings suggest that bisphosphonates (excluding alendronate and pamidronate) or denosumab compared to no treatment or placebo likely results in increased bone mineral density and reduced fracture rates. Our survival analysis that included pre and postmenopausal women showed little to no difference regarding overall survival. These treatments may lead to more adverse events. Therefore, forming an overall judgement of the best ranked bone-modifying agent is challenging. More head-to-head comparisons, especially comparing denosumab with any bisphosphonate, are needed to address gaps and validate the findings of this review.


Asunto(s)
Conservadores de la Densidad Ósea , Densidad Ósea , Neoplasias de la Mama , Difosfonatos , Metaanálisis en Red , Ligando RANK , Ensayos Clínicos Controlados Aleatorios como Asunto , Humanos , Femenino , Neoplasias de la Mama/tratamiento farmacológico , Conservadores de la Densidad Ósea/uso terapéutico , Difosfonatos/uso terapéutico , Densidad Ósea/efectos de los fármacos , Ligando RANK/antagonistas & inhibidores , Ligando RANK/uso terapéutico , Ácido Zoledrónico/uso terapéutico , Calidad de Vida , Osteoporosis/tratamiento farmacológico , Denosumab/uso terapéutico , Fracturas Osteoporóticas/prevención & control , Ácido Risedrónico/uso terapéutico , Ácido Ibandrónico/uso terapéutico , Ácido Clodrónico/uso terapéutico , Pamidronato/uso terapéutico
4.
Cochrane Database Syst Rev ; 4: CD013856, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38588457

RESUMEN

BACKGROUND: Physical exercise is effective in managing Parkinson's disease (PD), but the relative benefit of different exercise types remains unclear. OBJECTIVES: To compare the effects of different types of physical exercise in adults with PD on the severity of motor signs, quality of life (QoL), and the occurrence of adverse events, and to generate a clinically meaningful treatment ranking using network meta-analyses (NMAs). SEARCH METHODS: An experienced information specialist performed a systematic search for relevant articles in CENTRAL, MEDLINE, Embase, and five other databases to 17 May 2021. We also searched trial registries, conference proceedings, and reference lists of identified studies up to this date. SELECTION CRITERIA: We included randomized controlled trials (RCTs) comparing one type of physical exercise for adults with PD to another type of exercise, a control group, or both. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data. A third author was involved in case of disagreements. We categorized the interventions and analyzed their effects on the severity of motor signs, QoL, freezing of gait, and functional mobility and balance up to six weeks after the intervention using NMAs. Two review authors independently assessed the risk of bias using the risk of bias 2 (RoB 2) tool and rated the confidence in the evidence using the CINeMA approach for results on the severity of motor signs and QoL. We consulted a third review author to resolve any disagreements. Due to heterogeneous reporting of adverse events, we summarized safety data narratively and rated our confidence in the evidence using the GRADE approach. MAIN RESULTS: We included 154 RCTs with a total of 7837 participants with mostly mild to moderate disease and no major cognitive impairment. The number of participants per study was small (mean 51, range from 10 to 474). The NMAs on the severity of motor signs and QoL included data from 60 (2721 participants), and 48 (3029 participants) trials, respectively. Eighty-five studies (5192 participants) provided safety data. Here, we present the main results. We observed evidence of beneficial effects for most types of physical exercise included in our review compared to a passive control group. The effects on the severity of motor signs and QoL are expressed as scores on the motor scale of the Unified Parkinson's Disease Rating Scale (UPDRS-M) and the Parkinson's Disease Questionnaire 39 (PDQ-39), respectively. For both scales, higher scores denote higher symptom burden. Therefore, negative estimates reflect improvement (minimum clinically important difference: -2.5 for UPDRS-M and -4.72 for PDQ-39). Severity of motor signs The evidence from the NMA (60 studies; 2721 participants) suggests that dance and gait/balance/functional training probably have a moderate beneficial effect on the severity of motor signs (dance: mean difference (MD) -10.18, 95% confidence interval (CI) -14.87 to -5.36; gait/balance/functional training: MD -7.50, 95% CI -11.39 to -3.48; moderate confidence), and multi-domain training probably has a small beneficial effect on the severity of motor signs (MD -5.90, 95% CI -9.11 to -2.68; moderate confidence). The evidence also suggests that endurance, aqua-based, strength/resistance, and mind-body training might have a small beneficial effect on the severity of motor signs (endurance training: MD -5.76, 95% CI -9.78 to -1.74; aqua-based training: MD -5.09, 95% CI -10.45 to 0.40; strength/resistance training: MD -4.96, 95% CI -9.51 to -0.40; mind-body training: MD -3.62, 95% CI -7.24 to 0.00; low confidence). The evidence is very uncertain about the effects of "Lee Silverman Voice training BIG" (LSVT BIG) and flexibility training on the severity of motor signs (LSVT BIG: MD -6.70, 95% CI -16.48 to 3.08; flexibility training: MD 4.20, 95% CI -1.61 to 9.92; very low confidence). Quality of life The evidence from the NMA (48 studies; 3029 participants) suggests that aqua-based training probably has a large beneficial effect on QoL (MD -15.15, 95% CI -23.43 to -6.87; moderate confidence). The evidence also suggests that mind-body, gait/balance/functional, and multi-domain training and dance might have a small beneficial effect on QoL (mind-body training: MD -7.22, 95% CI -13.57 to -0.70; gait/balance/functional training: MD -6.17, 95% CI -10.75 to -1.59; multi-domain training: MD -5.29, 95% CI -9.51 to -1.06; dance: MD -3.88, 95% CI -10.92 to 3.00; low confidence). The evidence is very uncertain about the effects of gaming, strength/resistance, endurance, and flexibility training on QoL (gaming: MD -8.99, 95% CI -23.43 to 5.46; strength/resistance training: MD -6.70, 95% CI -12.86 to -0.35; endurance training: MD -6.52, 95% CI -13.74 to 0.88; flexibility training: MD 1.94, 95% CI -10.40 to 14.27; very low confidence). Adverse events Only 85 studies (5192 participants) provided some kind of safety data, mostly only for the intervention groups. No adverse events (AEs) occurred in 40 studies and no serious AEs occurred in four studies. AEs occurred in 28 studies. The most frequently reported events were falls (18 studies) and pain (10 studies). The evidence is very uncertain about the effect of physical exercise on the risk of adverse events (very low confidence). Across outcomes, we observed little evidence of differences between exercise types. AUTHORS' CONCLUSIONS: We found evidence of beneficial effects on the severity of motor signs and QoL for most types of physical exercise for people with PD included in this review, but little evidence of differences between these interventions. Thus, our review highlights the importance of physical exercise regarding our primary outcomes severity of motor signs and QoL, while the exact exercise type might be secondary. Notably, this conclusion is consistent with the possibility that specific motor symptoms may be treated most effectively by PD-specific programs. Although the evidence is very uncertain about the effect of exercise on the risk of adverse events, the interventions included in our review were described as relatively safe. Larger, well-conducted studies are needed to increase confidence in the evidence. Additional studies recruiting people with advanced disease severity and cognitive impairment might help extend the generalizability of our findings to a broader range of people with PD.


Asunto(s)
Terapia por Ejercicio , Metaanálisis en Red , Enfermedad de Parkinson , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Humanos , Enfermedad de Parkinson/rehabilitación , Terapia por Ejercicio/métodos , Equilibrio Postural , Ejercicio Físico , Sesgo
5.
Chem Sci ; 15(15): 5496-5506, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38638216

RESUMEN

Tetrapyridyl-functionalized phosphinines were prepared and structurally characterized. The donor-functionalized aromatic phosphorus heterocycles react highly selectively and even reversibly with water. Calculations reveal P,N-cooperativity for this process, with the flanking pyridyl groups serving to kinetically enhance the formal oxidative addition process of H2O to the low-coordinate phosphorus atom via H-bonding. Subsequent tautomerization forms 1,2-dihydrophosphinine derivatives, which can be quantitatively converted back to the phosphinine by applying vacuum, even at room temperature. This process can be repeated numerous times, without any sign of decomposition of the phosphinine. In the presence of CuI·SMe2, dimeric species of the type ([Cu2I2(phosphinine)]2) are formed, in which each phosphorus atom shows the less common µ2-bridging 2e--lone-pair-donation to two Cu(i)-centres. Our results demonstrate that fully unsaturated phosphorus heterocycles, containing reactive P[double bond, length as m-dash]C double bonds, are interesting candidates for the activation of E-H bonds, while the aromaticity of such compounds plays an appreciable role in the reversibility of the reaction, supported by NICS calculations.

6.
Chemistry ; 30(33): e202400592, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38597259

RESUMEN

Triazaphospholes are potential polydentate ligands due to the presence of both phosphorus and nitrogen donor atoms within the aromatic 5-membered heterocycle. The incorporation of an additional pyridyl-substituent opens up the possibility of a post-synthesis modification via chemoselective and also stepwise alkylation exclusively of the nitrogen atoms. This can be controlled by the choice and by the stoichiometry of the electrophile and allows the targeted synthesis of a variety of novel mono- and dicationic ligands. Reaction with Cu(I)-halides causes the formation of cuprates of the type [CuXn](n-1)-, which enables coordination of the π-acidic phosphorus donor to the negatively charged metal core, which is favored over the coordination by a strongly σ-donating nitrogen atom. The use of cationic triazaphosphole derivatives can be used as a strategy to enforce the coordination of the ligand to an electron rich metal solely via the phosphorus atom. However, there is a subtle balance between the formation of either coordination polymers or dimeric structures, as the substitution pattern on the heterocycle and the nature of the halide have a large influence on the coordination motifs formed.

7.
J Parkinsons Dis ; 14(s1): S115-S133, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38457150

RESUMEN

Background: Physical exercise interventions are known to improve quality of life, motor and non-motor symptoms in people with Parkinson's disease (PD). However, systematic reviews and meta-analyses on cognitive outcomes are rare. Objective: To perform a systematic review and meta-analysis of physical exercise intervention effects compared with passive and active control groups (CGs) on global cognition in people with PD. Methods: A literature search was performed for randomized controlled trials (RCTs) on physical exercise interventions in PD using nine databases. We included RCTs reporting global cognition outcomes. A meta-analysis was performed using random-effects models and standardized mean differences (SMDs) with 95% confidence intervals (CIs). Bias was assessed with the revised Cochrane Risk of Bias tool and the certainty of evidence was rated using the GRADE approach. Results: Seventeen studies (ten with passive, seven with active CGs) were included in the systematic review. Exercise interventions varied considerably between studies. The meta-analysis included nine studies with 236 people with PD (seven with passive, two with active CGs). The SMD was 0.33 (95% CI 0.00; 0.65) demonstrating a small effect (p = 0.05) in favor of physical exercise. Compared with passive CGs, physical exercise had a small non-significant effect (SMD = 0.22, 95% CI -0.14;0.58, p = 0.24). Compared with active CGs, physical exercise had a medium significant effect (SMD = 0.72, 95% CI 0.12;1.33, p = 0.02). Conclusions: Physical exercise may increase global cognition in people with PD, but the evidence is very uncertain. Further large-scale RCTs are needed to confirm this finding and to identify the most effective type of physical exercise for improving cognition.


Asunto(s)
Terapia por Ejercicio , Enfermedad de Parkinson , Humanos , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/rehabilitación , Enfermedad de Parkinson/terapia , Terapia por Ejercicio/métodos , Cognición/fisiología , Ejercicio Físico/fisiología , Disfunción Cognitiva/etiología , Disfunción Cognitiva/rehabilitación , Disfunción Cognitiva/terapia , Ensayos Clínicos Controlados Aleatorios como Asunto
8.
Molecules ; 29(5)2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38474627

RESUMEN

Reactions of the technetium(I) nitrosyl complex [Tc(NO)(Cp)(PPh3)Cl] with triphenylphosphine chalcogenides EPPh3 (E = O, S, Se), and Ag(PF6) in a CH2Cl2/MeOH mixture (v/v, 2/1) result in an exchange of the chlorido ligand and the formation of [Tc(NO)(Cp)(PPh3)(EPPh3)](PF6) compounds. The cationic acetonitrile complex [Tc(NO)(Cp)(PPh3)(NCCH3)]+ is formed when the reaction is conducted in NCCH3 without additional ligands. During the isolation of the corresponding PF6- salt a gradual decomposition of the anion was detected in the solvent mixture applied. The yields and the purity of the product increase when the BF4- salt is used instead. The acetonitrile ligand is bound remarkably strongly to technetium and exchange reactions readily proceed only with strong donors, such as pyridine or ligands with 'soft' donor atoms, such as the thioether thioxane. Substitutions on the cyclopentadienyl ring do not significantly influence the ligand exchange behavior of the starting material. 99Tc NMR spectroscopy is a valuable tool for the evaluation of reactions of the complexes of the present study. The extremely large chemical shift range of this method allows the ready detection of corresponding ligand exchange reactions. The observed 99Tc chemical shifts depend on the donor properties of the ligands. DFT calculations support the discussions about the experimental results and provide explanations for some of the unusual findings.

9.
Disabil Rehabil ; : 1-10, 2024 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-38343163

RESUMEN

PURPOSE: To explore the perspectives of people with Parkinson's disease (PD) and exercise providers regarding facilitating factors, barriers, needs, and demands relating to physical exercise for people with PD. MATERIALS AND METHODS: Focus group discussions or telephone interviews of 30 people with PD (with or without an active sports history) and 13 providers were conducted and analyzed using structuring content analysis. RESULTS: Factors facilitating participation in physical exercise included motivation-enhancing elements (enjoyment, group training environment) and providers with sufficient qualifications in PD-specific training demands. Identified barriers were lack of motivation, physical limitations, poor service accessibility, and inadequate matching of intervention groups based on capability or age. Providers found it difficult to design and conduct group trainings for people with PD with varying physical limitations. Having an active sports history before PD-onset was described as generally beneficial, though a competitive mindset could lead to frustration. People with PD reported needing their physicians to provide better education regarding physical exercise. CONCLUSION: Enjoyment of physical exercise is a key aspect of maintaining physical activity engagement, which should be considered more in research and clinical practice. Developing qualifications for providers could help to broaden and enhance the dissemination of PD-specific exercise approaches. Physicians should be trained to encourage physical exercise.Implications for rehabilitationPhysicians should highlight the benefits and be knowledgeable regarding the availability of physical exercise interventions for people with PD.Additional physical exercise providers should become qualified to work with people with PD.The joyfulness of physical exercise interventions is a key aspect of maintaining physical activity engagement for people with PD.

10.
Psychol Sci ; 35(3): 250-262, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38289294

RESUMEN

Fundamental frequency ( fo) is the most perceptually salient vocal acoustic parameter, yet little is known about how its perceptual influence varies across societies. We examined how fo affects key social perceptions and how socioecological variables modulate these effects in 2,647 adult listeners sampled from 44 locations across 22 nations. Low male fo increased men's perceptions of formidability and prestige, especially in societies with higher homicide rates and greater relational mobility in which male intrasexual competition may be more intense and rapid identification of high-status competitors may be exigent. High female fo increased women's perceptions of flirtatiousness where relational mobility was lower and threats to mating relationships may be greater. These results indicate that the influence of fo on social perceptions depends on socioecological variables, including those related to competition for status and mates.


Asunto(s)
Voz , Adulto , Humanos , Masculino , Femenino , Homicidio , Percepción Social , Parejas Sexuales
11.
J Parkinsons Dis ; 13(5): 659-679, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37334618

RESUMEN

BACKGROUND: Fatigue is one of the most common and debilitating non-motor symptoms among patients with Parkinson's disease (PD) and significantly impacts quality of life. Therefore, effective treatment options are needed. OBJECTIVE: To provide an update on randomized controlled trials (RCTs) including pharmacological and non-pharmacological (but non-surgical) treatments that examine the effects of fatigue on PD patients. METHODS: We searched the MEDLINE, EMBASE, PsycINFO, CENTRAL, and CINAHL databases for (cross-over) RCTs on pharmacological and non-pharmacological interventions for treating fatigue in PD patients until May 2021. Meta-analyses for random-effects models were calculated when two or more studies on the same treatment option were available using standardized mean differences (SMDs) with 95% confidence intervals (CIs). RESULTS: Fourteen pharmacological and 16 non-pharmacological intervention RCTs were identified. For pharmacological approaches, a meta-analysis could only be performed for modafinil compared to placebo (n = 2) revealing a non-significant effect on fatigue (SMD = - 0.21, 95% CI - 0.74-0.31, p = 0.43). Regarding non-pharmacological approaches, physical exercise (n = 8) following different training approaches versus passive or placebo control groups showed a small significant effect (SMD = - 0.37, 95% CI - 0.69- - 0.05, p = 0.02) which could not be demonstrated for acupuncture vs. sham-acupuncture (SMD = 0.16, 95% CI - 0.19-0.50, p = 0.37). CONCLUSION: Physical exercise may be a promising strategy to treat fatigue in PD patients. Further research is required to examine the efficacy of this treatment strategy and further interventions. Future studies should differentiate treatment effects on physical and mental fatigue as the different underlying mechanisms of these symptoms may lead to different treatment responses. More effort is required to develop, evaluate, and implement holistic fatigue management strategies for PD patients.


Asunto(s)
Enfermedad de Parkinson , Humanos , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/terapia , Ejercicio Físico , Modafinilo , Calidad de Vida
12.
Dtsch Arztebl Int ; 120(17): 289-296, 2023 04 28.
Artículo en Inglés | MEDLINE | ID: mdl-36942797

RESUMEN

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is the most common malignant B-cell neoplasm, with an incidence of 5.6 per 100 000 persons per year and a mean age of onset of approximately 65 years. It is an aggressive type of non-Hodgkin's lymphoma requiring urgent treatment with curative intent. Evidence-based guidelines have not been available to date. METHODS: For this first international evidence-based DLBCL-specific guideline, various systematic literature searches were performed. 5 systematic reviews, 21 randomized controlled trials (RCTs), and 36 non-randomized studies were used to formulate 42 recommendations. 142 were formulated on the basis of expert consensus. All recommendations were approved in a structured consensus-finding process. RESULTS: For staging, combined positron emission tomography and computed tomography (PET/CT) should be performed (evidence: a prospective registry study). For all patients with a new diagnosis of DLBCL and without contraindications, R-CHOP based immunochemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) should be initiated with curative intent (evidence: RCTs). The individual treatment strategy is tailored to the patient's age and risk constellation. Once immunochemotherapy has been completed, PET/CT should be performed again to check for remission. Patients with PET-positive residual disease that is amenable to radiotherapy should be treated with consolidating irradiation (evidence: retrospective cohort study). CONCLUSION: This clinical practice guideline on the diagnosis, treatment, and followup of patients with DLBCL and related entities provides a standardized clinical management approach, identifies areas where improvement would be desirable, and can serve as a basis for the development of further studies.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica , Linfoma de Células B Grandes Difuso , Anciano , Humanos , Anticuerpos Monoclonales de Origen Murino/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ciclofosfamida/uso terapéutico , Doxorrubicina/uso terapéutico , Linfoma de Células B Grandes Difuso/terapia , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Prednisona/uso terapéutico , Rituximab/uso terapéutico , Vincristina/uso terapéutico
13.
Strahlenther Onkol ; 199(2): 115-120, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36598520

RESUMEN

PURPOSE: Diffuse large B­cell lymphoma (DLBCL) is an aggressive lymphoma subtype treated successfully with immunochemotherapy. However, there are conflicting data on the role and impact of consolidative radiation therapy (RT). The publication of the national evidence-based guideline on DLBCL prompted us to review relevant passages on radiation oncology. METHODS: The following article reviews the evidence and recommendations given in the current German evidence-based guideline on DLBCL regarding RT and summarizes pivotal aspects. Additional literature is presented to provide a comprehensive background for the published recommendations. RESULTS: RT shall be administered to all patients with localized positron emission tomography(PET)-positive residues after completion of immunochemotherapy and should use a dose of 30-40 Gray in normofractionation. For RT planning, PET information before and after immunochemotherapy shall be used, with either a PET-CT in the RT treatment position or an image fusion to the planning CT. Conformal techniques shall be used for target volume coverage, with a risk-benefit evaluation for the individual patient. Additionally, RT may be used in the treatment context of various subtypes of DLBCL as well as in the recurrent or refractory treatment situation. CONCLUSION: RT remains an integral part of the treatment repertoire of DLBCL. With the use of PET-guided treatment, RT is indicated for patients with metabolically active tumors. In the context of the ongoing development of targeted therapies, new RT indications may evolve.


Asunto(s)
Linfoma de Células B Grandes Difuso , Tomografía Computarizada por Tomografía de Emisión de Positrones , Humanos , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Oncólogos de Radiación , Linfoma de Células B Grandes Difuso/diagnóstico por imagen , Linfoma de Células B Grandes Difuso/radioterapia , Tomografía de Emisión de Positrones
14.
Cochrane Database Syst Rev ; 1: CD013856, 2023 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-36602886

RESUMEN

BACKGROUND: Physical exercise is effective in managing Parkinson's disease (PD), but the relative benefit of different exercise types remains unclear. OBJECTIVES: To compare the effects of different types of physical exercise in adults with PD on the severity of motor signs, quality of life (QoL), and the occurrence of adverse events, and to generate a clinically meaningful treatment ranking using network meta-analyses (NMAs). SEARCH METHODS: An experienced information specialist performed a systematic search for relevant articles in CENTRAL, MEDLINE, Embase, and five other databases to 17 May 2021. We also searched trial registries, conference proceedings, and reference lists of identified studies up to this date. SELECTION CRITERIA: We included randomized controlled trials (RCTs) comparing one type of physical exercise for adults with PD to another type of exercise, a control group, or both. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data. A third author was involved in case of disagreements.  We categorized the interventions and analyzed their effects on the severity of motor signs, QoL, freezing of gait, and functional mobility and balance up to six weeks after the intervention using NMAs. Two review authors independently assessed the risk of bias using the risk of bias 2 (RoB 2) tool and rated the confidence in the evidence using the CINeMA approach for results on the severity of motor signs and QoL. We consulted a third review author to resolve any disagreements. Due to heterogeneous reporting of adverse events, we summarized safety data narratively and rated our confidence in the evidence using the GRADE approach. MAIN RESULTS: We included 156 RCTs with a total of 7939 participants with mostly mild to moderate disease and no major cognitive impairment. The number of participants per study was small (mean 51, range from 10 to 474). The NMAs on the severity of motor signs and QoL included data from 71 (3196 participants), and 55 (3283 participants) trials, respectively. Eighty-five studies (5192 participants) provided safety data. Here, we present the main results. We observed evidence of beneficial effects for most types of physical exercise included in our review compared to a passive control group. The effects on the severity of motor signs and QoL are expressed as scores on the motor scale of the Unified Parkinson Disease Rating Scale (UPDRS-M) and the Parkinson's Disease Questionnaire 39 (PDQ-39), respectively. For both scales, higher scores denote higher symptom burden. Therefore, negative estimates reflect improvement (minimum clinically important difference: -2.5 for UPDRS-M and -4.72 for PDQ-39). Severity of motor signs The evidence from the NMA (71 studies; 3196 participants) suggests that dance has a moderate beneficial effect on the severity of motor signs (mean difference (MD) -10.32, 95% confidence interval (CI) -15.54 to -4.96; high confidence), and aqua-based, gait/balance/functional, and multi-domain training might have a moderate beneficial effect on the severity of motor signs (aqua-based: MD -7.77, 95% CI -13.27 to -2.28; gait/balance/functional: MD -7.37, 95% CI -11.39 to -3.35; multi-domain: MD -6.97, 95% CI -10.32 to -3.62; low confidence). The evidence also suggests that mind-body training and endurance training might have a small beneficial effect on the severity of motor signs (mind-body: MD -6.57, 95% CI -10.18 to -2.81; endurance: MD -6.43, 95% CI -10.72 to -2.28; low confidence). Flexibility training might have a trivial or no effect on the severity of motor signs (MD 2.01, 95% CI -4.82 to 8.98; low confidence). The evidence is very uncertain about the effects of strength/resistance training and "Lee Silverman Voice training BIG" (LSVT BIG) on the severity of motor signs (strength/resistance: MD -6.97, 95% CI -11.93 to -2.01; LSVT BIG: MD -5.49, 95% CI -14.74 to 3.62; very low confidence). Quality of life The evidence from the NMA (55 studies; 3283 participants) suggests that aqua-based training probably has a large beneficial effect on QoL (MD -14.98, 95% CI -23.26 to -6.52; moderate confidence). The evidence also suggests that endurance training might have a moderate beneficial effect, and that gait/balance/functional and multi-domain training might have a small beneficial effect on QoL (endurance: MD -9.16, 95% CI -15.68 to -2.82; gait/balance/functional: MD -5.64, 95% CI -10.04 to -1.23; multi-domain: MD -5.29, 95% CI -9.34 to -1.06; low confidence). The evidence is very uncertain about the effects of mind-body training, gaming, strength/resistance training, dance, LSVT BIG, and flexibility training on QoL (mind-body: MD -8.81, 95% CI -14.62 to -3.00; gaming: MD -7.05, 95% CI -18.50 to 4.41; strength/resistance: MD -6.34, 95% CI -12.33 to -0.35; dance: MD -4.05, 95% CI -11.28 to 3.00; LSVT BIG: MD 2.29, 95% CI -16.03 to 20.44; flexibility: MD 1.23, 95% CI -11.45 to 13.92; very low confidence). Adverse events Only 85 studies (5192 participants) provided some kind of safety data, mostly only for the intervention groups. No adverse events (AEs) occurred in 40 studies and no serious AEs occurred in four studies. AEs occurred in 28 studies. The most frequently reported events were falls (18 studies) and pain (10 studies). The evidence is very uncertain about the effect of physical exercise on the risk of adverse events (very low confidence). Across outcomes, we observed little evidence of differences between exercise types. AUTHORS' CONCLUSIONS: We found evidence of beneficial effects on the severity of motor signs and QoL for most types of physical exercise for people with PD included in this review, but little evidence of differences between these interventions. Thus, our review highlights the importance of physical exercise regarding our primary outcomes severity of motor signs and QoL, while the exact exercise type might be secondary. Notably, this conclusion is consistent with the possibility that specific motor symptoms may be treated most effectively by PD-specific programs. Although the evidence is very uncertain about the effect of exercise on the risk of adverse events, the interventions included in our review were described as relatively safe. Larger, well-conducted studies are needed to increase confidence in the evidence. Additional studies recruiting people with advanced disease severity and cognitive impairment might help extend the generalizability of our findings to a broader range of people with PD.


Asunto(s)
Enfermedad de Parkinson , Entrenamiento de Fuerza , Adulto , Humanos , Enfermedad de Parkinson/terapia , Metaanálisis en Red , Ejercicio Físico , Marcha , Calidad de Vida
15.
J Parkinsons Dis ; 12(6): 1783-1806, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35754291

RESUMEN

BACKGROUND: Previous reviews indicated positive effects of resistance training (RT) on motor outcomes in Parkinson's disease (PD). However, inconsistencies between the included studies exist, and non-motor outcomes have only scarcely been considered in a review on RT in PD. OBJECTIVE: To analyze the RT effects on motor- and non-motor outcomes in PD patients compared to passive and physically active control groups (i.e., other structured physical interventions). METHODS: We searched CENTRAL, MEDLINE, EMBASE, and CINAHL for randomized controlled trials of RT in PD. After identifying 18 studies, a meta-analysis was conducted for the outcomes muscle strength, motor impairment, freezing of gait (FoG), mobility and balance, quality of life (QoL), depression, cognition, and adverse events. Meta-analyses with random models were calculated using mean differences (MD) or standardized mean differences (SMD) with 95% confidence intervals (CI). RESULTS: When comparing RT with passive control groups, the meta-analyses showed significant large effects on muscle strength (SMD = -0.84, 95% CI -1.29--0.39, p = 0.0003), motor impairment (SMD = -0.81, 95% CI -1.34--0.27, p = 0.003), mobility and balance (MD = -1.81, 95% CI -3.13--0.49, p = 0.007), and small significant effects on QoL (SMD = -0.48, 95% CI -0.86--0.10, p = 0.01). RT compared with physically active control groups reached no significant results for any outcome. CONCLUSIONS: RT improves muscle strength, motor impairment, mobility and balance, QoL, and depression in PD patients. However, it is not superior to other physically active interventions. Therefore, exercise is important for PD patients but according to this analysis, its type is of secondary interest.


Asunto(s)
Trastornos Neurológicos de la Marcha , Enfermedad de Parkinson , Entrenamiento de Fuerza , Trastornos Neurológicos de la Marcha/etiología , Humanos , Fuerza Muscular/fisiología , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/terapia , Calidad de Vida , Entrenamiento de Fuerza/métodos
16.
Cochrane Database Syst Rev ; 9: CD013365, 2021 09 13.
Artículo en Inglés | MEDLINE | ID: mdl-34515338

RESUMEN

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer of the lymphatic system. About 30% to 40% of people with DLBCL experience relapse and 10% are refractory to first-line treatment usually consisting of R-CHOP chemotherapy. Of those eligible for second-line treatment, commonly consisting of salvage chemotherapy followed by autologous stem-cell transplantation (ASCT), around 50% experience relapse. With a median overall survival of less than six to 12 months, the prognosis of individuals who relapse or are refractory (r/r) to advanced lines of treatment or of those who are ineligible for ASCT, is very poor. With the introduction of chimeric antigen receptor (CAR) T-cell therapy, a novel treatment option for these people is available. OBJECTIVES: To assess the benefits and harms of chimeric antigen receptor (CAR) T-cell therapy for people with relapsed or refractory (r/r) DLBCL. SEARCH METHODS: An experienced information specialist performed a systematic database search for relevant articles on CENTRAL, MEDLINE and Embase until September 11th, 2020. We also searched trial registries and reference lists of identified studies up to this date. All search results were screened by two authors independently and a third author was involved in case of discrepancies. SELECTION CRITERIA: We included prospectively planned trials evaluating CAR T-cell therapy for people with r/r DLBCL. We had planned to include randomised controlled trials (RCTs) and we flexibly adapted eligibility criteria to the most reliable study designs available. We excluded studies involving fewer than 10 participants with r/r DLBCL and studies with a proportion of participants with r/r DLBCL below 70%, unless data were reported separately for this subgroup. DATA COLLECTION AND ANALYSIS: Two review authors extracted data and performed risk of bias ratings independently. A third author was involved in case of disagreements. As our search did not yield any completed RCTs, prospective controlled non-randomised studies of interventions (NRSIs) or prospective observational studies with a control group, we did not meta-analyse data and reported all results narratively. We adopted the GRADE approach to assess the certainty of the evidence for prioritised outcomes. MAIN RESULTS: We identified 13 eligible uncontrolled studies evaluating a single or multiple arms of CAR T-cell therapies. We also identified 38 ongoing studies, including three RCTs. Ten studies are awaiting classification due to completion with no retrievable results data or insufficient data to justify inclusion. The mean number of participants enrolled, treated with CAR T-cell therapy and evaluated in the included studies were 79 (range 12 to 344; data unavailable for two studies), 61 (range 12 to 294; data unavailable for one study) and 52 (range 11 to 256), respectively. Most studies included people with r/r DLBCL among people with other haematological B-cell malignancies. Participants had received at least a median of three prior treatment lines (data unavailable for four studies), 5% to 50% had undergone ASCT (data unavailable for five studies) and, except for two studies, 3% to 18% had undergone allogenic stem-cell transplantation (data unavailable for eight studies). The overall risk of bias was high for all studies, in particular, due to incomplete follow-up and the absence of blinding. None of the included studies had a control group so that no adequate comparative effect measures could be calculated. The duration of follow-up varied substantially between studies, in particular, for harms. Our certainty in the evidence is very low for all outcomes. Overall survival was reported by eight studies (567 participants). Four studies reported survival rates at 12 months which ranged between 48% and 59%, and one study reported an overall survival rate of 50.5% at 24 months. The evidence is very uncertain about the effect of CAR T-cell therapy on overall survival. Two studies including 294 participants at baseline and 59 participants at the longest follow-up (12 months or 18 months) described improvements of quality of life measured with the EuroQol 5-Dimension 5-Level visual analogue scale (EQ-5D-5L VAS) or Function Assessment of Cancer Therapy-Lymphoma (FACT-Lym). The evidence is very uncertain about the effect of CAR T-cell therapy on quality of life. None of the studies reported treatment-related mortality. Five studies (550 participants) reported the occurrence of adverse events among participants, ranging between 99% and 100% for any grade adverse events and 68% to 98% for adverse events grade ≥ 3. In three studies (253 participants), 56% to 68% of participants experienced serious adverse events, while in one study (28 participants), no serious adverse events occurred. CAR T-cell therapy may increase the risk of adverse events and serious adverse events but the evidence is very uncertain about the exact risk. The occurrence of cytokine release syndrome (CRS) was reported in 11 studies (675 participants) under use of various grading criteria. Five studies reported between 42% and 100% of participants experiencing CRS according to criteria described in Lee 2014. CAR T-cell therapy may increase the risk of CRS but the evidence is very uncertain about the exact risk. Nine studies (575 participants) reported results on progression-free survival, disease-free survival or relapse-free survival. Twelve-month progression-free survival rates were reported by four studies and ranged between 44% and 75%. In one study, relapse-free survival remained at a rate of 64% at both 12 and 18 months. The evidence is very uncertain about the effect of CAR T-cell therapy on progression-free survival. Thirteen studies (620 participants) provided data on complete response rates. At six months, three studies reported complete response rates between 40% and 45%. The evidence is very uncertain about the effect of CAR T-cell therapy on complete response rates. AUTHORS' CONCLUSIONS: The available evidence on the benefits and harms of CAR T-cell therapy for people with r/r DLBCL is limited, mainly because of the absence of comparative clinical trials. The results we present should be regarded in light of this limitation and conclusions should be drawn very carefully. Due to the uncertainty in the current evidence, a large number of ongoing investigations and a risk of substantial and potentially life-threatening complications requiring supplementary treatment, it is critical to continue evaluating the evidence on this new therapy.


Asunto(s)
Linfoma de Células B Grandes Difuso , Receptores Quiméricos de Antígenos , Tratamiento Basado en Trasplante de Células y Tejidos , Humanos , Inmunoterapia Adoptiva , Linfoma de Células B Grandes Difuso/terapia , Recurrencia Local de Neoplasia , Estudios Observacionales como Asunto
17.
Angew Chem Int Ed Engl ; 59(36): 15480-15486, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32270577

RESUMEN

Herein we describe the first examples of isolable electron-precise diboranes(4) that bear azide moieties: the acyclic 1,2-diazido-1,2-bis(dimethylamino)diborane(4) and the cyclic 1,4-diaryl-2,3-diazido-1,4-diaza-2,3-diborinines (aryl=mesityl, 2,6-xylyl, 4-tolyl). The reported examples are not only stable enough to be observed and isolated (putative transient diborane(4) azides previously reported by our group spontaneously decompose even below room temperature), but some of them are even robust enough to undergo controlled pyrolysis without explosive decomposition at temperatures well above 100 °C. In two cases, the controlled pyrolysis allows the isolation of complex diazaboretidines, which are the apparent dimerization products of endocyclic boryl-iminoboranes.

18.
Chemistry ; 26(13): 2967-2972, 2020 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-31944442

RESUMEN

Several bis(dimethylamino)-substituted 1,4-diaza-2,3-diborinines (DADBs) were synthesized with variable substituents at the backbone nitrogen atoms. By reaction with HCl or BX3 (X=Br, I), these species were successfully converted into their synthetically more useful halide congeners. The high versatility of the generated B-X bonds in further functionalization reactions at the boron centers was demonstrated by means of salt elimination (MeLi) and commutation (NMe2 DADBs) reactions, thus making the DADB system a general structural motif in diborane(4) chemistry. A total of 18 DADB derivatives were characterized in the solid state by X-ray diffraction, revealing a strong dependence of the heterocyclic bonding parameters from the exocyclic substitution pattern at boron. According to our experiments towards the realization of a Dipp-substituted, sterically encumbered DADB, the mechanism of DADB formation proceeds via a transient four-membered azadiboretidine intermediate that subsequently undergoes ring expansion to afford the six-membered DADB heterocycle.

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