bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of the Hox Gene Cluster
Authors: Ferrier David EK 
Published: April 2013

AbstractThe Hox genes are a family of developmental control genes containing a homeobox motif, and tend to be organised in distinctive clustered arrays in animals. Organisation within the cluster can relate to how the genes function. Whilst much has been discovered about the Hox gene cluster in traditional model systems of developmental biology, increasing amounts of data from a wider variety of species are illuminating more about the nature of the Hox cluster deep in animal ancestry, as well as revealing the evolutionary flexibility and derivations along present‐day lineages. The consensus view of the Hox cluster is that it patterns the anterior–posterior axis of bilaterally symmetrical (bilaterian) animals and exhibits the phenomenon of colinearity. There is, however, much evolutionary change within this system. This diversity in the Hox system is linked to the evolution of animal diversity and informs our understanding of the pre‐bilaterian origins of the Hox genes themselves.Key Concepts:Spatial colinearity is the phenomenon whereby the order of the expression domains of the Hox genes along the anterior–posterior axis of the embryo corresponds with the order of the genes along the chromosome.Temporal colinearity is a further form of colinearity in which the Hox genes in some taxa are activated progressively, with the earliest time at which a gene is activated matching its position within the Hox cluster.Anterior–posterior patterning by the Hox genes is distinct from the initial determination of the anterior–posterior axis and instead involves the specification of different developmental fates within the anterior–posterior axis of an embryo. This is one of the major roles of the Hox genes within the bilaterians, but the Hox genes do have further roles in development subsequent to this anterior–posterior patterning function.A range of Hox gene organisation has evolved across different lineages, forming organised, disorganised, split and atomised Hox clusters, such that the Hox genes of some species are not actually organised into a Hox gene cluster.
Eye Movements
Authors: Mackay Devin D , Prasad Sashank 
Published: April 2013

Abstract

Eye movements are produced by six extraocular muscles for each eye, which are controlled by the third, fourth and sixth cranial nerves, their nuclei, and specialized populations of neurons in the medulla, pons, midbrain, cerebellum and cerebral hemispheres. Together, these neurons allow the eyes to move quickly together to an object of interest (saccades), follow a moving target (pursuit), maintain ocular alignment (conjugate gaze), and converge on a close target (vergence). Vestibular inputs allow vision to remain fixed on an object despite head movement, whereas their suppression helps the eyes and head follow a moving object together. A lesion in the pathways subserving eye movements leads to characteristic abnormalities that can often be localised upon careful clinical examination. Understanding the anatomy of these pathways and common diseases that affect them facilitates accurate diagnosis and appropriate treatment.

Key Concepts:

The third, fourth, and sixth cranial nerves are the final common pathway for all eye movements.

Binocular diplopia (that resolves with either eye covered) is the cardinal clinical symptom of misalignment of the eyes.

Saccades are fast conjugate eye movements that direct the eyes to a point of interest and originate with signals in the cortex.

Pursuits are slower conjugate eye movements that allow the eyes to follow a moving point of interest.

Abnormalities of conjugate horizontal eye movements may localise to the pons, where saccadic eye movements are controlled by neurons of the paramedian pontine reticular formation (PPRF) and maintained by neurons of the nucleus prepositus hypoglossus.

Abnormalities of conjugate vertical eye movements may localise to the midbrain, where saccadic eye movements are controlled by neurons of the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and maintained by neurons of the interstitial nucleus of Cajal (inC).

Head and eye movements are coordinated by information from the semicircular canals and otolith organs and their specialized connections with the ocular motor nuclei.

The medial longitudinal fasciculus (MLF) is a highly myelinated fibre tract connecting the abducens nuclei and contralateral oculomotor nuclei, serving to facilitate rapid coordinated horizontal eye movements and maintain conjugate gaze.

Nystagmus (back and forth oscillations of the eyes) primarily results from abnormalities of the slow eye movement systems and gaze‐holding mechanisms.
Diabetic Neuropathies
Authors: Said Gérard 
Published: April 2013

Abstract

Diabetes is the most common cause of peripheral neuropathy in the world. Both type 1 (insulin‐dependent) and type 2 diabetes are commonly complicated by peripheral nerve disorders. Two main types of neuropathy are observed: the most common is a nerve fibre length dependent, distal symmetrical sensory polyneuropathy with little motor involvement but frequent, and potentially life threatening, autonomic dysfunction. Alteration of temperature and pain sensations in the feet is an early manifestation of diabetic polyneuropathy. The second pattern is a focal neuropathy which more commonly complicates or reveal type 2 diabetes. Poor diabetic control increases the risk of neuropathy with subsequent neuropathic pains and trophic changes in the feet, which can be prevented by patient's education.

Key Concepts:

Length‐dependent diabetic polyneuropathy is the most common neuropathy in the world.

Neuropathic pains are the most common symptoms of diabetic neuropathy.

Charcot joints and plantar ulcers are favored by loss of pain sensation.

Autonomic dysfunction is commonly associated with small fibre diabetic neuropathy.

The prevalence of diabetic polyneuropathy increases with duration and poor diabetic control.

Focal neuropathies are more common in type 2 diabetic patient.
Cerebral Palsy
Authors: Feather Danielle N , Ferguson Tanya S 
Published: April 2013

AbstractCerebral palsy is a nonprogressive movement disorder that causes permanent motor disabilities. It occurs in 3:1000 live births in the United States annually. Although it is considered a motor disorder, the symptoms of cerebral palsy are due to brain damage that occurs eitherin utero, during birth or within the first 2 years of life. Birth asphyxia was thought to be the primary cause of cerebral palsy; however, birth complications, including asphyxia, account for less than 10% of all known cases. The aetiology of the remaining 90% of cerebral palsy cases is unknown, suggesting that an undetected or undiagnosedin uteroevent is the primary cause. Many maternal risk factors have been identified, including multiple births, toxin exposure and high blood pressure. Fetal stroke and inflammation due to maternal infection may also play a role. There is no cure, only management of symptoms. Treatment includes various therapies as well as pharmaceuticals to decrease symptoms. Surgery may also be an option. Current research is investigating both the cause of and treatments for cerebral palsy with some recent promising results.Key Concepts:Cerebral palsy is a nonprogressive movement disorder.It is identified by a typical pattern of brain injury to the motor regions of the brain, often before birth.The different types of cerebral palsy are named after their location and symptoms.The cause of cerebral palsy is unknown; however, many risk factors have been identified.Treatment involves symptom management.Research is currently focused on early detection, a potential cure and better symptoms management.
Exosome Complex
Authors: Chlebowski Aleksander , Dziembowski Andrzej 
Published: April 2013

Abstract

A living cell consists in a dynamic equilibrium of many opposing processes. Steady‐state levels of all
ribonucleic acid
(RNA) and protein molecules result from a specific balance between constant production and ongoing decay. RNA degradation is thus of paramount importance for the cell's wellbeing. A major player in this process is the exosome complex. It is a multisubunit entity endowed with
ribonuclease
activities. It is highly conserved in evolution, found in all
Eukaryota
and most
Archaea
;
Eubacteria
lack the exosome but they do have a very similar enzyme. The eukaryotic exosome has endo‐ and exoribonuclease activity and it engages a plethora of substrates in numerous pathways of RNA decay, RNA processing and RNA surveillance. Substrate specificity is conferred by a wide range of cofactors, some of them multisubunit complexes with interaction networks of their own.

Key Concepts:

The exosome core is a conserved protein complex.

Exosomes of
Archaea
and
Eukaryota
have different enzymatic activities.

Catalytic activity in eukaryotic exosomes comes from noncore subunits.

Catalytic subunits are organised differently in yeast, plants and mammals.

The exosome participates in RNA decay, processing and surveillance.

Many cofactors are responsible for recruiting substrates to the exosome.
Bacteriophages: Structure
Authors: Cuervo Ana , Carrascosa José L 
Published: April 2013

Abstract

Bacterial viruses, or bacteriophages, are ubiquitous organisms spanning very different ecological niches. Although genome comparison fails to show extensive relationship among bacteriophages, recent structural studies reveal a high degree of similarities. Most bacteriophages present an icosahedral proteinaceous head, which contains the nucleic acid, either
deoxyribonucleic acid (DNA)
or
ribonucleic acid (RNA)
. Exceptions to this rule are few cases where a lipid envelope forms part of the head, and those other cases where the head presents a filamentous geometry. The way bacteriophages infect the host cell is the basis of a main difference among them: one group (Caudovirales) has a specialised structure (the tail) that is responsible for the recognition of the host cell and the viral genome delivery, whereas those bacteriophages without tail present a variety of infecting strategies. In this study we will deal with the main common characteristics of bacteriophage heads and tails supporting their common evolutionary origin.

Key Concepts:

Bacteriophages share extended structural and functional similarities.

Bacteriophages are excellent examples of optimisation of genetic information to carry out complex functions.

Most bacteriophages enclose their nucleic acid in a protein container (built by multiple copies of one (or a few) proteins), and in a few cases they may include lipid envelopes.

The most conserved geometry in bacteriophage heads is icosahedral.

Double stranded DNA icosahedral bacteriophages follow a common assembly pathway.

The Caudovirales group (bacteriophages with icosahedral heads, dsDNA and a tail) are the most abundant virus type.

The packaging of dsDNA inside Caudovirales requires energy conversion (ATP hydrolysis) into mechanical translocation, and it is carried out by a dedicated viral machinery.

The maturation of icosahedral proheads into viral heads involves drastic reorganisations of the capsid components leading to more stable particles.

The tail of Caudovirales is a sophisticated machinery involved in cell recognition and nucleic acids delivery.

There are three main architectural designs of bacteriophage tails, each one adapting to different host interaction strategies.
Ethical Use of Placebo in Research and Practice
Authors: Zhang Hongliang 
Published: April 2013

AbstractA placebo means a therapy or medical intervention that is used for its nonspecific psychophysiological effects, but is without actual effects on the condition being treated. The placebo effect denotes effects due to the meaning of an intervention. The placebo effect has the potential to augment the efficacy of all active medical treatments and procedures. The placebo effect and placebo constitute a convergence point for the social, psychological and physiological aspects of illness and health. The use of placebo has long been controversial, and the ethics of placebos have been debated frequently in history. In recent years, accumulating ethical concern has arisen from the common use of placebo in randomised controlled trials, which may render its participants without early and optimal treatment. This review presents an overview of placebo‐associated ethical questions and offers considerations that are of relevance to medical and research practise.Key Concepts:A placebo means a therapy or medical intervention that is used for its nonspecific psychophysiological effects, but is without actual effects on the condition being treated.The placebo effect is genuine psychobiological events attributed to the overall therapeutic context.Ethics is a branch of philosophy that involves systematising, defending and recommending concepts of right and wrong conduct.A randomized controlled trial is a study in which people are allocated at random to receive one of several clinical interventions.Evidence‐based medicine is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.
Genetically Modified Food: Ethical Issues
Authors: Thompson Paul B 
Published: April 2013

Abstract

The use of recombinant DNA technology to transform agricultural plants and animals has been the subject of ethical controversy for the last quarter century. The argument favouring these technologies hinges on their role in lowering costs of farm production, as well as potential benefits to farmers. Arguments against cite a long litany of problems. Environmental and food safety risk debates touch upon both the nature and likelihood of potential hazards, and also the overall philosophy that should guide the assessment and management of these risks. In addition, critics of the technology have argued that risk assessments have neglected two categories of hazard entirely: impact on animals and socio‐economic impacts, especially on organic and smallholder farms. The latter issue makes the use of genetic engineering into a key episode in a more comprehensive debate over the future of agricultural production. In addition, ethical debates have taken up the extension of intellectual property rights to genes and their impact on the use, production and control of seeds. Labelling and consumer choice has also been debated. Finally, some authors have extended arguments over the possible unnatural character of genetic engineering from their more conventional medical setting to the domain of food.

Key Concepts:

Environmental and food safety hazards associated with genetically modified foods are not unique to the process of transformation that utilises recombinant DNA techniques.

Risk assessment and policy decision making for genetically modified foods has generally excluded socio‐economic impacts and effects on small farmers from consideration.

Concern over unequal distribution of power often lurks just beneath the surface of criticisms that have been levied against genetically engineered foods.
Hsp90 Chaperones
Authors: Zierer Bettina K , Buchner Johannes 
Published: April 2013

AbstractHeat shock protein 90 (Hsp90) is an abundant molecular chaperone especially important in the cytosol of eukaryotic cells. Its function is coupled to large conformational rearrangements within the dimer coupled to nucleotide binding. Hsp90 assists a large set of so‐called ‘client’ proteins to stay folded or to achieve an active conformation. These client proteins include among others protein kinases and many transcription factors such as steroid hormone receptors. The function of the Hsp90 chaperone machinery itself is highly regulated on several levels. A large set of cochaperones as well as post‐translational modifications help to fine‐tune the conformational cycle. Inhibition of the low intrinsicadenosine triphosphatase(ATPase) activity of Hsp90 leads to destabilisation of its clients resulting in their degradation. As many of the clients are oncogenes, inhibition of Hsp90 is an important target in cancer therapy.Key Concepts:Hsp90 is an essential molecular chaperone in eukaryotes.Hsp90 function is coupled to nucleotide‐induced conformational changes.Hsp90 stabilises the active state of a large set of clients.Hsp90 function can be regulated via cochaperones or post‐translational modifications.Inhibition of Hsp90 is an anticancer strategy.
Sex Assignment in Disorders of Sex Development
Authors: Lucas‐Herald Angela K , Faisal Ahmed S 
Published: April 2013

Abstract

Disorders of sex development (DSD) are relatively rare conditions with diverse pathophysiology, which usually present in the newborn or adolescent periods. These conditions are very heterogeneous and can present in a variety of different ways, most commonly with ambiguous genitalia noticed in the newborn period or delayed puberty in adolescents. The impact of these disorders on the lives of these patients and their families should not be underestimated. These clinical situations can often be difficult to manage, particularly in those cases where the sex of rearing is uncertain. The needs of each individual patient presenting with DSD conditions must be fully considered, along with the needs of their families and where appropriate, cultural practices. The multidisciplinary team should be involved from early in the diagnosis and ethical principles must be considered at all stages of management of the condition.

Key Concepts:

Disorders of sex development usually present in the newborn or adolescent periods.

There are three broad groups of DSD: sex chromosome DSD; 46,XY DSD and 46,XX DSD.

Where there is uncertainty about the sex of a patient, sex assignment should be delayed until appropriate investigations have been carried out.

A multidisciplinary team should be involved from an early stage.

The psychosocial implications of a diagnosis of DSD must be considered for the family and the patient.
Obesity and Appetite Hormones in Humans: an Overview
Authors: Caylak Emrah 
Published: April 2013

Abstract

Obesity is one of the most important public health problems in the world. It is a medical condition with a chronic imbalance between energy intake and energy expenditure. The prevalence of overweight and obesity in adults and children are rapidly rising, and several factors contributing the increased risk of developing obesity are inactivity, overeating, age, give up smoking, ethnicity, secondary obesity and inherited predisposition or genetic defects.
The regulation of appetite involves highly complex peripheral and central systems that are processed in the brain. The appetite hormones (hypothalamic orexigenic neuropeptides) play critical roles in the control of food intake and obesity. Understanding the pharmacology and physiology of appetite regulation and investigation of the role of appetite hormones in the regulation of food intake in humans will allow us to find potential therapeutic targets for the treatment of obesity.

Key Concepts:

Obesity is a medical condition, with excessed body weight in the form of fat, resulted from the failure of energy homoeostasis.

Many factors cause obesity including inactivity, overeating, higher age, drugs, diseases, ethnicity and inherited predisposition to obesity or specific genetic defects.

Obesity is most prevalent in worldwide, WHO predicted that they would rise up to 2.3 billion overweight and 700 million obese in 2015.

Obesity predisposes some chronic diseases as type 2 diabetes, cardiovascular diseases and various cancers or shortens life duration and increases mortality rates.

Neural and humoral signals regulate appetite in brain. The appetite hormones control food intake and energy expenditure, whereas a chronic imbalance in those hormones causes obesity.
Ghrelin Appetite Hormone in Health and Disease
Authors: Caylak Emrah 
Published: April 2013

Abstract

Ghrelin is a 28‐amino‐acid appetite hormone and has numerous physiological roles in appetite modulation, glucose and lipid metabolisms, gastrointestinal, cardiovascular, reproductive, pulmonary and bone systems or immune modulation and cell proliferation. Recent studies implicate ghrelin in the pathogenesis of many diseases, including obesity, Prader–Willi syndrome, cachexia, Anorexia nervosa, cardiovascular diseases, reproductive disorders, diabetes and inflammatory bowel disease. Understanding the pharmacology and physiology of ghrelin agonists and antagonists and investigation of the role of appetite hormones in the regulation of food intake in humans will allow us to find potential therapeutic managements for the treatment of many of those diseases.

Key Concepts:

Ghrelin, a 28 amino‐acid peptide hormone that was discovered as an endogenous ligand for the growth hormone secretagogue‐receptor (GHS‐R), has two circulating forms: acylated and desacyl. The acylated form is essential for ghrelin's biological activity through GHS‐R. It is produced primarily in the stomach, hypothalamus, pituitary, intestine, kidney, heart, lung, gonads and placenta.

Ghrelin is peripheral circulating appetite hormone, acts as a physiological hunger signal. Its secretion and blood levels rise during fasting and fall after eating. It stimulates appetite and increases food intake via secretion of GH. Repeated administration of ghrelin results in decreased energy expenditure; thus, increasing body fat and weight.

Ghrelin have major biological functions in glucose and lipid metabolism and main physiological systems such as gastrointestinal, cardiovascular, reproductive, pulmonary, bone and immune.

Ghrelin appears to be involved in the pathophysiological mechanisms of several human disorders, including obesity, Prader–Willi syndrome, cachexia, Anorexia nervosa, cardiovascular diseases, reproductive disorders, diabetes and inflammatory bowel disease.
Anorexigenic Peptides in Health and Disease
Authors: Caylak Emrah 
Published: April 2013

Abstract

The regulation of satiety and body weight involves highly complex multiple interactions between the gastrointestinal tract, adipose tissue and central nervous system. Several neuropeptides released by hypothalamic neurons including corticotropin‐releasing factor, α‐melanocyte stimulating hormone, corticotropin, brain‐derived neurotrophic factor, cocaine‐ and amphetamine‐regulated transcript, neuropeptides B, neuropeptides W and nesfatin‐1; and gastrointestinal hormones including obestatin, pancreatic polypeptide, amylin, cholecystokinin, peptide YY, oxyntomodulin, glucagon‐like peptide‐1 are reviewed in this article, emphasising both their effects on regulating satiety, and their physiological roles in many systems.
The dysfunctions of anorexigenic peptides in those processes will result metabolic disorders such as obesity and type 2 diabetes. The purpose of this review is also to consider the important roles of anorexigenic peptides including nesfatin‐1, obestatin, amylin and glucagon‐like peptide‐1 in obesity‐related pathophysiological conditions.

Key Concepts:

Satiety is the satisfied feeling of being full after eating. It refers to the inhibition of eating following a meal.

Neuropeptides released by hypothalamic neurons play a major role in the regulation of feeding such as CRF, melanocortins, BDNF, CART, neuropeptides B, neuropeptides W and nesfatin‐1.

Anorexigenic peptides released by gastrointestinal tract play a major role in the inhibition of food intake such as obestatin, pancreatic polypeptide, amylin, CCK, peptide YY, OXM and GLP‐1.

Obesity is the major contributor to cardiovascular disease, metabolic disorders (type 1 or 2 diabetes) and various cancers.

Obesity predisposes humans some chronic diseases as type 2 diabetes, cardiovascular diseases, and cancers or it shortens life duration and increases mortality rates.

Understanding the physiological and pathological roles of anorexigenic peptides in health and disease in humans will allow us to find potential therapeutic targets for the treatment of many disorders.