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Maximal oxygen uptake (.VO(2,max)) is a physiological characteristic bounded by the parametric limits of the Fick equation: (left ventricular (LV) end-diastolic volume--LV end-systolic volume) x heart rate x arterio-venous oxygen difference. 'Classical' views of .VO(2,max) emphasize its critical dependence on convective oxygen transport to working skeletal muscle, and recent data are dispositive, proving convincingly that such limits must and do exist. 'Contemporary' investigations into the mechanisms underlying peripheral muscle fatigue due to energetic supply/demand mismatch are clarifying the local mediators of fatigue at the skeletal muscle level, though the afferent signalling pathways that communicate these environmental conditions to the brain and the sites of central integration of cardiovascular and neuromotor control are still being worked out. Elite endurance athletes have a high .VO(2,max) due primarily to a high cardiac output from a large compliant cardiac chamber (including the myocardium and pericardium) which relaxes quickly and fills to a large end-diastolic volume. This large capacity for LV filling and ejection allows preservation of blood pressure during extraordinary rates of muscle blood flow and oxygen transport which support high rates of sustained oxidative metabolism. The magnitude and mechanisms of cardiac phenotype plasticity remain uncertain and probably involve underlying genetic factors, as well as the length, duration, type, intensity and age of initiation of the training stimulus.  相似文献   

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Although a potentially helpful therapeutic tool, dream interpretation or dream work is only used occasionally in most forms of psychotherapy. Despite an interest from clinicians and clients alike in using dreams within therapy, many therapists feel unprepared to attend to their clients' dreams. The main goals of this article are to make clinicians aware that integrating dreams into their clinical practice is both accessible and potentially valuable and to allow them to make an informed decision as to what role they want dream work to play in therapy. The paper begins with a brief overview of some of the more common approaches to dream work. The literature on the usefulness and effectiveness of the clinical use of dreams is then reviewed. Finally, based on the integration of the clinical and empirical literature, several guidelines for conducting dream work are presented.  相似文献   

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Considering increasing number of pathogens resistant towards commonly used antibiotics as well as antiseptics, there is a pressing need for antimicrobial approaches that are capable of inactivating pathogens efficiently without the risk of inducing resistances. In this regard, an alternative approach is the antimicrobial photodynamic therapy (aPDT). The antimicrobial effect of aPDT is based on the principle that visible light activates a per se non-toxic molecule, the so-called photosensitizer (PS), resulting in generation of reactive oxygen species that kill bacteria unselectively via an oxidative burst. During the last 10–20 years, there has been extensive in vitro research on novel PS as well as light sources, which is now to be translated into clinics. In this review, we aim to provide an overview about the history of aPDT, its fundamental photochemical and photophysical mechanisms as well as photosensitizers and light sources that are currently applied for aPDT in vitro. Furthermore, the potential of resistances towards aPDT is extensively discussed and implications for proper comparison of in vitro studies regarding aPDT as well as for potential application fields in clinical practice are given. Overall, this review shall provide an outlook on future research directions needed for successful translation of promising in vitro results in aPDT towards clinical practice.  相似文献   

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BackgroundInflammatory myofibroblastic tumors (IMTs) are rare intermediate-grade neoplasms that have a high recurrence rate after excision and exhibit low metastatic potential. These tumors contain proliferating neoplastic, fibroblastic and myofibroblastic cells, and are also characterized by chronic inflammatory infiltration by lymphocytes, plasma cells, eosinophils, and histiocytes. They belong to the group of inflammatory spindle cell lesions. Some reactive lesions, such as inflammatory pseudotumors, may appear to be IMTs, which makes their differential diagnosis extremely difficult. The aim of this article is to compile the recent information on IMTs to aid in their diagnosis and treatment.MethodsWe reviewed articles published between 2017 and 2021, which were selected from online medical databases. In addition, some earlier articles and latest scientific monographies were analyzed.ResultsThe terminology used for inflammatory spindle cell lesions seems to be confusing. The terms “inflammatory myofibroblastic tumors” and “inflammatory pseudotumors” are interchangeably used by many scientists. However, a detailed analysis of the development of terminology suggests that the term “inflammatory myofibroblastic tumors” should be used to refer to a neoplastic lesion.ConclusionsIMTs are rare neoplasms, which have not been investigated in detail due to the difficulty in collecting a large number of cases. Thus, our knowledge about this disease remains unsatisfactory. Recently developed techniques such as next-generation sequencing and computer-aided histopathological diagnosis may be useful in understanding the etiopathology of IMTs, which will help in the selection of the most appropriate therapy for patients.  相似文献   

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PEComa: what do we know so far?   总被引:13,自引:0,他引:13  
PEComas (tumours showing perivascular epithelioid cell differentiation) are a family of related mesenchymal neoplasms that include angiomyolipoma, lymphangiomyomatosis, clear cell "sugar" tumour of the lung, and a group of rare, morphologically and immunophenotypically similar lesions arising at a variety of visceral and soft tissue sites. These tumours all share a distinctive cell type, the perivascular epithelioid cell or "PEC' (which has no known normal tissue counterpart). PEComas show a marked female predominance and are composed of nests and sheets of usually epithelioid but occasionally spindled cells with clear to granular eosinophilic cytoplasm and a focal association with blood vessel walls. PEComas appear to arise most commonly at visceral (especially gastrointestinal and uterine), retroperitoneal, and abdominopelvic sites, with a subset occurring in somatic soft tissue and skin. Nearly all PEComas show immunoreactivity for both melanocytic (HMB-45 and/or melan-A) and smooth muscle (actin and/or desmin) markers. A subset of PEComas behave in a malignant fashion. This review examines the members of the PEComa family, with an emphasis on lesions arising outside of the kidney, lung and liver, and discusses preliminary evidence for pathological features that might predict malignant behaviour.  相似文献   

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In order to cope with normal cognitive aging we must understand the patterns and neurofunctional underpinnings of cognitive and behavioral changes throughout adulthood. In this review, we summarize recent advances in our understanding of age-related behavioral differences and changes in brain structure throughout the spatial domain. Although spatial cognition is critically important to everyday life, few studies have examined the relationship between this cognitive function and neural changes in the aged brain. Thus, spatial cognition is considered a key area in which the cognitive neuroscience of aging may expand in the near future. The first section of this review examines the methodologies and studies used to assess differences in spatial cognition during normal cognitive aging in animals and humans. We then relate how each domain of spatial cognition (e.g., visuospatial perception, mental imagery, memory and navigation) is affected by the aging process, and discuss possible links with changes in neural mechanisms. Lastly, we address putative links among the age-related deterioration patterns of the various spatial domains and make suggestions for future research.  相似文献   

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Much has been written about the effects of aging on reproductive function, especially female fertility. Much less is known about how aging may affect the contractility of the smooth muscle within the uterus, the myometrium. The myometrium is active through a woman's entire life, not just during pregnancy. Here we will discuss briefly the contractile functions of the uterus and the changes it undergoes throughout the stages of a woman's life from menstruation and the menopause, before evaluating the evidence for any changes in myometrial contractility and responses as women age, with a particular focus on women of advanced maternal age. We present original contractility analysis for the widest data set for human myometrium so far examined, and determine inherent spontaneous activity as well as responses to depolarisation and stimulation with oxytocin. Our data show that in the non-pregnant state there is a significant decrease in contractility for both spontaneous and depolarised-induced contractions, with age. We suggest that muscle atrophy and down regulation of Ca channels may account for this. Interestingly in pregnant myometrium we found a wide range of contractile ability between women and little evidence for decreased spontaneous activity between the ages of 25-40. Oxytocin responses appear to be more affected by aging, a finding that is consistent with previously reported clinical findings, and may partly be the result of membrane lipids such as cholesterol, increasing as women age. The marked differences between the age-related decline of force beyond age 30 in non-pregnant uterus, and the lack of difference in the pregnant state over this period, shows that the uterus retains its ability to respond to gestational hormones. The growth of the pregnant uterus and increase in content of myofibrillar proteins, may abolish any previous age-related force deficit. This finding is consistent with what is apparent for postmenopausal women in their 50s and 60s; that with the appropriate hormonal stimulation the uterus can allow an embryo to implant, and then without further intervention, carry the foetus to term. It is tempting therefore to speculate that unlike other well documented declines in female reproductive functions with age, the myometrium remains able to function into a woman's 7th decade.  相似文献   

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BackgroundOver the past 25 years, researchers have performed >120 randomized controlled trials (RCTs) illustrating short courses to be non-inferior to long courses of antibiotics for common bacterial infections.ObjectiveWe sought to determine whether clinical data from RCTs affirm the mantra of ‘shorter is better’ for antibiotic durations in 7 common infections: pneumonia, urinary tract infection, intra-abdominal infection, bacteraemia, skin and soft tissue infection, bone and joint infections, pharyngitis and sinusitis.SourcesPublished RCTs comparing short- versus long-course antibiotic durations were identified through searches of PubMed and clinical guideline documents.ContentShort-course antibiotic durations consistently result in similar treatment success rates as longer antibiotic courses among patients with community-acquired pneumonia, complicated urinary tract infections in women, gram-negative bacteraemia, and skin and soft tissue infections when the diagnosis is confirmed, appropriate antimicrobials are used, and patients show clinical signs of improvement. For patients with osteomyelitis, 6 weeks of antibiotics is adequate for the treatment of osteomyelitis in the absence of implanted foreign bodies and surgical debridement. Whether durations can be further shortened with debridement is unclear, although small studies are promising.ImplicationsWith few exceptions, short courses were non-inferior to long courses; future research should focus on appropriately defining the patient population, ensuring the correct choice and dose of antimicrobials and developing meaningful outcomes relevant for frontline clinicians.  相似文献   

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The pandemic condition coronavirus disease (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can take asymptomatic, mild, moderate, and severe courses. COVID-19 affects primarily the respiratory airways leading to dry cough, fever, myalgia, headache, fatigue, and diarrhea and can end up in interstitial pneumonia and severe respiratory failure. Reports about the manifestation of various skin lesions and lesions of the vascular system in some subgroups of SARS-CoV-2-positive patients as such features outside the respiratory sphere, are rapidly emerging. Vesicular, urticarial, and maculopapular eruptions and livedo, necrosis, and other vasculitis forms have been reported most frequently in association with SARS-CoV-2 infection. In order to update information gained, we provide a systematic overview of the skin lesions described in COVID-19 patients, discuss potential causative factors, and describe differential diagnostic evaluations. Moreover, we summarize current knowledge about immunologic, clinical, and histologic features of virus- and drug-induced lesions of the skin and changes to the vascular system in order to transfer this knowledge to potential mechanisms induced by SARS-CoV-2.  相似文献   

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Bradykinin is an endogenous nonapeptide known to induce pain and hyperalgesia to heat and mechanical stimulation. Correspondingly, it excites nociceptors in various tissues and sensitizes them to heat, whereas sensitizing effect on the mechanical response of nociceptors is not well established. Protein kinase C and TRPV1 contribute to the sensitizing mechanism of bradykinin to heat. In addition, TRPA1 and other ion channels appear to contribute to excitation caused by bradykinin. Finally, prostaglandins sensitize bradykinin-induced excitation in normal tissues by restoring desensitized responses due to the inhibition of protein kinase A.  相似文献   

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What do we really know about mindfulness-based stress reduction?   总被引:17,自引:0,他引:17  
OBJECTIVE: Mindfulness-Based Stress Reduction (MBSR) is a clinical program, developed to facilitate adaptation to medical illness, which provides systematic training in mindfulness meditation as a self-regulatory approach to stress reduction and emotion management. There has been widespread and growing use of this approach within medical settings in the last 20 years, and many claims have been made regarding its efficacy. This article will provide a critical evaluation of the available state of knowledge regarding MBSR and suggestions for future research. METHODS: A review of the current literature available within the medical and social sciences was undertaken to provide an evaluation regarding what we know about the construct of mindfulness, the effectiveness of MBSR, and mechanisms of action. RESULTS: There has been a paucity of research and what has been published has been rife with methodological problems. At present, we know very little about the effectiveness of this approach. However, there is some evidence that suggests that it may hold some promise. CONCLUSIONS: The available evidence does not support a strong endorsement of this approach at present. However, serious investigation is warranted and strongly recommended.  相似文献   

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The study of pathological gambling and its treatment is in a nascent stage. To date, no consistent definition of relapse to gambling exists, and only a few empirical studies have evaluated the phenomenon of relapse directly in this patient population. Perspectives on relapse to drug and alcohol use appear relevant to the study of pathological gambling, and relapse to gambling is reviewed within the larger context of addictive disorders. The application of psychological, biological, environmental, and treatment factors are described as they may relate to relapse among pathological gamblers.  相似文献   

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Although there is general agreement from studies demonstrating that adherence to inhaled corticosteroid therapy is often inadequate to establish consistent control, relatively little concurrence exists in reports of interventions to correct the problem. Half of the studies reviewed found that the experimental intervention did not change adherence, and behavior change reported by patients was often not accompanied by changes in treatment success. Studies used a variety of methods that differed in quality with findings that were often contradictory. Key limitations in many studies included reliance on inadequate adherence measures, inclusion of convenience samples of well-motivated patients, and assessments of intervention outcomes artificially boosted by attrition of least adherent participants. Research is encouraged into innovative interventions that are brief, easily implemented, and can be tailored to individual patients and diverse clinical settings. Of particular importance is inclusion of hard-to-reach patients, including urban and rural poor and the use of valid measures of adherence at intervals sufficient to establish enduring benefit.  相似文献   

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