Biofeedback in medicine: who,when, why and how?

Biofeedback is a mind-body technique in which individuals learn how to modify their physiology for the purpose of improving physical, mental, emotional and spiritual health. Much like physical therapy, biofeedback training requires active participation on the part of patients and often regular practice between training sessions. Clinical biofeedback may be used to manage disease symptoms as well as to improve overall health and wellness through stress management training. Research has shown that biofeedback interventions are efficacious in treating a variety of medical conditions, and many Americans are turning to biofeedback and other less traditional therapies for their routine healthcare.Clinical biofeedback training is growing increasingly popular in the USA, as many people are seeking out relatively new approaches to healthcare. This article provides an overview of clinical biofeedback training, outlines two models of training, details research which has established how effective biofeedback is in patients with a given disease, and describes who should be referred for biofeedback training.     

Plant species radiations: where,when, why?

The spatial and temporal patterns of plant species radiations are largely unknown. I used a nonlinear regression to estimate speciation and extinction rates from all relevant dated clades. Both are surprisingly high. A high species richness can be the result of either little extinction, thus preserving the diversity that dates from older radiations (a 'mature radiation'), or a 'recent and rapid radiation'. The analysis of radiations from different regions (Andes, New Zealand, Australia, southwest Africa, tropics and Eurasia) revealed that the diversity of Australia may be largely the result of mature radiations. This is in sharp contrast to New Zealand, where the flora appears to be largely the result of recent and rapid radiations. Mature radiations are characteristic of regions that have been climatically and geologically stable throughout the Neogene, whereas recent and rapid radiations are more typical of younger (Pliocene) environments. The hyperdiverse Cape and Neotropical floras are the result of the combinations of mature as well as recent and rapid radiations. Both the areas contain stable environments (the Amazon basin and the Cape Fold Mountains) as well as dynamic landscapes (the Andes and the South African west coast). The evolution of diversity can only be understood in the context of the local environment.     

Schistosome monogamy: who,how, and why?

Schistosomes represent a unique animal model for comparative analyses of monogamy. Indeed, schistosomes are classified at the lowest taxonomical level of monogamous species and lack complex social interactions, which could alter our understanding of their unusual mating system. Elements discussed here include the fact that monogamy in schistosomes could be an ancestral state between hermaphroditism and polygyny or polygynandry and the occurrence of mate changes. In addition, hypotheses are proposed to explain monogamy in schistosomes (e.g. female dispersion, the need for paternal care, oviposition site limitation or aggressiveness, and mate guarding). We also propose future experimental and analytical approaches to improve our understanding of the schistosomes' mating system.     

Extracellular small RNAs: what, where, why?

miRNAs (microRNAs) are a class of small RNA that regulate gene expression by binding to mRNAs and modulating the precise amount of proteins that get expressed in a cell at a given time. This form of gene regulation plays an important role in developmental systems and is critical for the proper function of numerous biological pathways. Although miRNAs exert their functions inside the cell, these and other classes of RNA are found in body fluids in a cell-free form that is resistant to degradation by RNases. A broad range of cell types have also been shown to secrete miRNAs in association with components of the RISC (RNA-induced silencing complex) and/or encapsulation within vesicles, which can be taken up by other cells. In the present paper, we provide an overview of the properties of extracellular miRNAs in relation to their capacity as biomarkers, stability against degradation and mediators of cell-cell communication.     

Alternative signaling pathways: when, where and why?

Alternative cell signal transduction pathways have been demonstrated in some experimental systems. The importance of their existence has not been completely appreciated. In this review we present the cases of alternative pathways resulted from a survey of the available experimental data. The alternative pathways could show different relationships, i.e., synergistic, redundant, additive, opposite and competitive effects. They could have distinct time courses and cell, organ, sex or species specification. Further, they could happen during physiological or pathological situations, and display differentiated sensitivity. These case studies together imply that alternative signal pathways could be involved in the regulation of cell functions at the pathway level. In-depth understanding of the importance of the alternative pathways will rely on building and exploration of mathematical models.     

Lipid trafficking sans vesicles: where, why, how?

Eukaryotic cells possess a remarkable diversity of lipids, which distribute among cellular membranes by well-characterized vesicle trafficking pathways. However, transport of lipids by alternate, or "nonvesicular," routes is also critical for lipid synthesis, metabolism, and proper membrane partitioning. In the past few years, considerable progress has been made in characterizing the mechanisms of nonvesicular lipid transport and how it may go awry in particular diseases, but many fundamental questions remain for this rising field.     

Signalling sphingomyelinases: which, where, how and why?

A major lipid signalling pathway in mammalian cells implicates the activation of sphingomyelinase (SMase), which upon cell stimulation hydrolyses the ubiquitous sphingophospholipid sphingomyelin to ceramide. This review summarizes our current knowledge on the nature and regulation of signalling SMase(s). Because of the controversy on the identity of this(these) phospholipase(s), the roles of various SMases in cell signalling are discussed. Special attention is also given to the subcellular site of action of signalling SMases and to the cellular factors that positively or negatively control their activity. These regulating agents include lipids (arachidonic acid, diacylglycerol and ceramide), kinases, proteases, glutathione and other proteins.     

Avian sex determination: what, when and where?

Sex is determined genetically in all birds, but the underlying mechanism remains unknown. All species have a ZZ/ZW sex chromosome system characterised by female (ZW) heterogamety, but the chromosomes themselves can be heteromorphic (in most birds) or homomorphic (in the flightless ratites). Sex in birds might be determined by the dosage of a Z-linked gene (two in males, one in females) or by a dominant ovary-determining gene carried on the W sex chromosome, or both. Sex chromosome aneuploidy has not been conclusively documented in birds to differentiate between these possibilities. By definition, the sex chromosomes of birds must carry one or more sex-determining genes. In this review of avian sex determination, we ask what, when and where? What is the nature of the avian sex determinant? When should it be expressed in the developing embryo, and where is it expressed? The last two questions arise due to evidence suggesting that sex-determining genes in birds might be operating prior to overt sexual differentiation of the gonads into testes or ovaries, and in tissues other than the urogenital system.     

The what, where, when and how of Wnt/β-catenin signaling in pancreas development

The Wnt/β-catenin signaling pathway, conserved across the animal kingdom, is critical for the development of numerous tissues. Several recent studies have focused on the roles that this pathway plays at different stages of pancreatic organogenesis, including specification, proliferation, differentiation and function. Whereas, during early endoderm development, inhibition of the pathway is required for pancreatic specification, subsequent growth and differentiation of the fetal organ depends on the pathway being active. This appears especially true for exocrine acinar cells, the specification and differentiation of which also depend on β-catenin function. Whether the pathway plays an important role in development or function of endocrine islet cells, including insulin-producing β-cells, remains controversial. This question is particularly important in light of recent studies that implicate a downstream component of the pathway, TCF7L2, in human β-cell function. This review will cover recent work on Wnt/β-catenin signaling in pancreas development, emphasizing those points of controversy that most urgently require further investigation.     

The what,where, when and how of Wnt/β-catenin signaling in pancreas development

The Wnt/β-catenin signaling pathway, conserved across the animal kingdom, is critical for the development of numerous tissues. Several recent studies have focused on the roles that this pathway plays at different stages of pancreatic organogenesis, including specification, proliferation, differentiation and function. Whereas, during early endoderm development, inhibition of the pathway is required for pancreatic specification, subsequent growth and differentiation of the fetal organ depends on the pathway being active. This appears especially true for exocrine acinar cells, the specification and differentiation of which also depend on β-catenin function. Whether the pathway plays an important role in development or function of endocrine islet cells, including insulin-producing β-cells, remains controversial. This question is particularly important in light of recent studies that implicate a downstream component of the pathway, TCF7L2, in human β-cell function. This review will cover recent work on Wnt/β-catenin signaling in pancreas development, emphasizing those points of controversy that most urgently require further investigation.     

Breaching the basement membrane: who, when and how?

The basement membrane (BM), a specialized network of extracellular matrix macromolecules, surrounds epithelial, endothelial, muscle, fat and nerve cells. During development, immune surveillance and disease states ranging from cancer to fibrosis, host cells penetrate the BM by engaging tissue-invasive programs, the identity of which remain largely undefined. Although it is commonly assumed that all cells employ similar mechanisms to cross BM barriers, accumulating evidence indicates that cells might selectively mobilize protease-dependent or -independent invasion programs. New data indicate that protease-dependent transmigration is largely reliant on a group of membrane-anchored metalloenzymes, termed the membrane-type matrix metalloproteinases, which irreversibly remodel BM structure. By contrast, mechanisms that enable protease-independent transmigration remain undefined and potentially involve the reversible disassembly of the BM network. Further characterization of the molecular mechanisms underlying BM transmigration should provide important insights into pathophysiologic tissue remodeling events and also enable the development of novel therapeutics.     

Physicians in health care management: 2. Managing performance: who,what, how and when?

Physicians are becoming more involved in performance management as hospitals restructure to increase effectiveness. Although physicians are not hospital employees, they are subject to performance appraisals because the hospitals are accountable to patients and the community for the quality of hospital services. The performance of a health care professional may be appraised by the appropriate departmental manager, by other professionals in a team or program or by peers, based on prior agreement on expectations. Appraisal approaches vary. They include behavioural approaches such as rating scales, peer rating, ranking or nomination and outcome approaches such as management by objectives and goal setting. Professionals should give and receive timely feedback on a flexible schedule. Feedback can be provided one-on-one, by a group assessing quality of care or through an anonymous survey.     

Episodic memory in nonhumans: what, and where, is when?

Episodic memory is defined as the recollection of specific events in one's past, accompanied by the experience of having been there personally. This definition presents high hurdles to the investigation of episodic memory in nonhumans. Recent studies operationalize episodic memory as memory for when and where an event occurred, for the order in which events occurred, or for an animal's own behavior. None of these approaches has yet generalized across species, and each fails to capture features of human episodic memory. Nonetheless, the study of episodic memory in nonhumans seems less daunting than it did five years ago. To demonstrate a correspondence between human episodic memory and nonhuman memory, progress is needed in three areas. Putative episodic memories in nonhumans should be shown to be; first, represented in long-term memory, rather than short-term or working memory; second, explicit, or accessible to introspection; and third, distinct from semantic memory, or general knowledge about the world.