bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retinoic acid receptors
Authors: Leroy Pierre , Krust Andrée , Kastner Philippe , Mendelsohn Cathy , Zelent Arthur , Chambon Pierre 
Published: November 2023

Abstract
The establishment of anatomical structures of the embryo throughout its development is thought to be controlled by morphogenctic molecules, which would instruct the cells of the three germ layers to differentiate according to their position with respect to organizing region(s) (Slack 1987a; Wolpert 1989; Summerbell and Maden 1990). Retinoic acid (RA) is generally believed to be a natural morphogen (Maden 1982; Tickle et al. 1982; Slack 1987h; Thaller and Eichele 1987; Smith et al. 1989; Eichele 1990), and plays an important role in the development and homeostasis of vertebrates (Chytil 1984; Maden 1985; Brockes 1989, 1990; Eichele 1989a,b; Durston et al. 1989; Sive et al. 1990; Wagner et al. 1900; Ruiz i Altaba and Jessel 1991; and references therein). However, recent reports raised a controversy by questioning the role of RA as a true morphogenetic signal (Brockes 1991; Wanek et al. 1991; Noji et al. 1991). The multiple effects exerted by RA on cultured cells or during development and in the adult, have often been correlated with changes in the expression patterns of specific genes (Wang and Gudas 1983; La Rosa and Gudas 1988; Murphy et al. 1988; Lüscher et al. 1989; Vasios et al. 1989; Chytil and Haq 1990; Okamoto et al. 1990; Simeone et al. 1990; Wang et al. 1990; Nicholson et al. 1990; Dinsmore and Solomon, 1991; and references therein). These observations suggest that RA may directly modulate gene expression through an RA-responsive machinery, which would ultimately interpret the putative morphogenetic signal provided by RA. The fine dissection of this “molecular machinery” is a prerequisite to a better understanding of RA-triggered positional signalling (see lzpisúa-Belmonte et al. 1991, for a discussion of this point).
Molecular mechanisms of retinoic acid action
Authors: Pfahl Magnus , Zhang Xiao-Kun , Lehmann Jürgen M , Husmann Matthias , Graupner Gerhart , Hoffmann Birgit 
Published: November 2023

Abstract
The multitude of essential biological processes regulated by the vitamin A derivative retinoic acid (RA) and synthetic analogues (retinoids) (reviewed in Lotan 1980; Sporn et al. 1984), combined with the many beneficial and undesirable side-effects (Lippman et al. 1987) associated with retinoid therapies, suggest the existence of a highly complex regulatory mechanism. How can a single substance —RA—regulate a large diversity of programmes and, in addition, provoke at times opposite effects, e.g. during limb morphogenesis, where low concentrations of RA can lead to duplications of digits, while high concentrations prevent digit formation (Tickle et al. 1982; Summerbell 1983). The discovery of nuclear retinoic acid receptors (RAR) that belong to the steroid-thyroid hormone receptor family represented a breakthrough towards the elucidation of a molecular mechanism of RA action (Petkovich et al. 1987; Giguère et al. 1987). These receptor proteins are ligand-dependent transcription factors that contain a highly conserved “zinc-finger” DNA binding domain and a less conserved hydrophobic ligand binding domain (Evans 1988; Green and Chambon 1988). The receptors modulate gene transcription by interacting with specific DNA sequences the responsive elements that are frequently located near the promoters of susceptible genes (Beato 1989).
Retinoic acid receptors in the chick embryo
Authors: Rowe Annie , Eager Nicholas S C , Richman Joy M , Brickell Paul M 
Published: November 2023

Abstract
The chicken is of particular value as an organism for studies of vertebrate embryonic development because chick embryos can be manipulated in ovo and the effects of such manipulations on their further development can be examined. Such studies have contributed a great deal to our view of the possible role of retinoids in vertebrate embryonic development. This is largely a result of experiments showing that the local application of all-trans-retinoic acid to the anterior margin of the chick wing bud results in the development of wings in which the pattern of the digits and other skeletal elements is altered. This behaviour mimics that of the polarizing region, a group of cells at the posterior margin of the limb bud that are involved in patterning the normal limb, and there is evidence that retinoids may be natural signalling substances in chick limb buds (reviewed by Tickle and Brickell 1991). For these reasons, we and others have analysed the chicken’s system of retinoic acid (RA) nuclear receptors. The purpose of this article is to review what is known about this system and then to concentrate on our own recent studies of the chicken R×R and RAR-β nuclear receptors.
Retinoic acid receptors and binding proteins in mouse limb development
Authors: Ruberte Esther , Nakshatri Harikrishna , Kastner Philippe , Chambon Pierre 
Published: November 2023

Abstract
The vertebrate limb appears as an outgrowth in the flank of the embryonic body. Initially it consists of a mesenchymal core covered by a layer of ectoderm. During the elongation of the limbs the apparently homogeneous population of the mesenchymal cells gives rise to different cell types: cartilage, bone, muscle, and other tissues, that develop in appropriate spatial relationships to constitute the developed limb. From grafting experiments that have been performed mainly in the chick, it appears that two mechanisms are involved in the formation of the proximodistal (from the base to the tip) and the anteroposterior (from the thumb to the little finger) pattern of the limbs. Development of the proximodistal axis involves the mesenchymal cells in the distal tip of the limbs, which through a mesenchymal-ectodermal interaction, induce the overlying ectoderm to thicken. This results in the formation of a pseudostratified columnar epithelium known as the apical ectodermal ridge (AER). This ridge appears to be essential for the outgrowth of the limbs and grafting experiments have shown that its removal results in a truncated limb (Zwilling 1956; Saunders and Gasseling 1968). Once the AER is formed it exerts an inductive influence on the underlying mesenchyme, which grows rapidly and differentiates. Positional values along the proximodistal axis are defined by the time spent in an area of undifferentiated mesenchyme under the tip of the bud, known as the progress zone (Summerbell et al. 1973). Cells leaving the progress zone at early times differentiate into proximal structures, while the cells that leave the progress zone later give rise to distal structures.
Differential regulation by retinoic acid of the homeobox genes of the HOX family in human embryonal carcinoma cells
Authors: Boncinelli Edoardo , Simeone Antonio , Acampora Dario , Faiella Antonio , D”Esposito Maurizio , Stornaiuolo Anna , Pannese Maria , Mallamaci Antonio 
Published: November 2023

Abstract
Morphogens, which convey positional information and induce pathways of differentiation through a gradient of concentration, are believed to play a key role in vertebrate development (Brockes 1989). Retinoic acid (RA) has been implicated as a natural morphogen in chicken development, where it contributes to the specification of the limb anterior-posterior (AP) axis (Tickle et al. 1982; Thaller and Eichele 1987). There is also a possible implication in frogs, where alteration of embryonic RA levels dramatically affects specific structures of the developing central nervous system (Durston et al. 1989), although these interpretations have recently been reconsidered (Brockes 1991). The identification of specific cellular RA binding proteins and of a number of nuclear RA receptors in mouse and man supports the concept that this substance may act as a morphogen with direct gene control functions. Although the genes involved in interpreting signals provided by morphogens are still unknown, homeobox genes, which specify positional information in Drosophila and possibly in vertebrate embryogenesis, are among suggested candidates. Extensive genetic analysis of early embryogenesis in Drosophila has provided insights into the molecular events controlling body plan formation and, in particular, the process of segmentation and the specification of segment identity along the body axis. These processes are controlled by a relatively limited number of genes, which appear to be organized in a complex regulatory network (Akam 1987). Most of them encode DNA-binding proteins with a role in transcriptional control (Levine and Hoey 1988). The DNA-binding domain present in these proteins is often a homeodomain (HD) encoded by a homeobox (Gehring 1987). Genes containing a homeobox code for nuclear proteins with regulatory functions in a wide variety of organisms, from yeast to man (Scott et al. 1989). Many of these genes appear to have a role in control of the early developmental programme. Unravelling this regulatory network is critical for our understanding of development.
Hox-4 genes, retinoic acid, and the specification of positional information during chick wing morphogenesis
Authors: Izpisúa-Belmonte Juan-Carlos , Dollé Pascal , Tickle Cheryll , Wolpert Lewis , Duboule Denis 
Published: November 2023

Abstract
The morphogenesis of the vertebrate limb is a widely used model system to study the cellular and molecular basis of positional signalling processes during development. A conceptual framework for pattern formation was provided by Wolpert (1969) who proposed that various cells within a developing system could have their positions specified relative to one or more reference points or organizing regions. Accordingly, each cell would then interpret its own positional value and respond by differentiating in a particular way according to its developmental history. Cells highly related, phenotypically and functionally, would therefore appear as “non-equivalent” (Lewis and Wolpert 1976) as far as patterning is concerned. The nature of the genetic control of”non-equivalence” is largely unknown, but the past few years have provided us with serious candidate genes for encoding positional information. Among them are the homeobox-containing (HOX) genes, which are the vertebrate gene cognates of the Drosophila homeotic genes. In insects, these genes specify the identities of the various parasegmental units in a position-dependent manner. In vertebrates, functional and circumstantial evidence suggest that the Hox genes encode positional information. Hox genes are responsive to retinoic acid (RA) treatment in vitro (Simeone et al. 1990) and it is well established that retinoids can respecify patterns in the developing vertebrate limb (Tickle et al. 1982, 1985). Here we discuss evidence that genes from the vertebrate Hox-4 complex might play a role in setting-up positional cues during mouse and chick limb development and that the expression of these genes can be regulated by RA in vivo.
Towards vaccines against papillomavirus
Authors: Campo M Saveria 
Published: November 2023

Abstract
As already described elsewhere (Chapter 2), papillomaviruses induce a variety of lesions both in humans and in animals. Some papillomas, albeit benign, are themselves a clinical problem, such as laryngeal papillomas of children (Steinberg 1987) or penile papillomas of bulls (Jarrett 1985), and others are known to be a risk factor in the pathogenesis of cancer. In humans, papillomavirus infection of the genital tract can lead to squamous cell carcinoma particularly in the uterine cervix (zur Hausen 1991), and infection of the skin by certain virus types can develop into squamous cancer in immunosuppressed individuals (Orth 1987). In animals, the link between papillomavirus and cancer of the skin in rabbits, and of the urinary bladder and the upper alimentary canal in cattle, is well documented (Kreider 1980; Campo and Jarrett 1986; Campo et al. 1992).
Quantification of grains in in situ hybridization
Authors: Aldridge Jane 
Published: November 2023

Abstract
Image analysis provides a wide range of sophisticated measurement techniques. Even so, it is often difficult to analyse histological and cytological preparations automatically since, in many cases, standard detection methods simply do not interpret the image well enough on their own to find the regions to be measured. This is particularly true for radiolabelled in situ hybridization. The issue of recognition is complex, since the best approach to interpreting an image automatically often depends on background information about the sample and about the aims of the experiment. Important changes in the approach adopted by manufacturers of image analysis equipment are promising advances. The first is a shift away from developing general analysis software and towards developing analysis software that will solve particular problems in interpreting types of images.
The Sawflies And Woodwasps
Authors: Smith David R 
Published: November 2023

Abstract
As is traditionally recognized (e.g. by Gauld & Bolton, 1988; Naumann, 1991; Smith, 1993), the suborder Symphyta (the sawflies and woodwasps) is a para phyletic assemblage comprising the structurally more primitive Hymenoptera. Symphytan adults share a number of primitive (plesiomorphic) character states: their abdomen is broadly joined to the thorax and not constricted at its base, the first abdominal segment is not fused with thorax (i.e. propodeum absent), cenchri are present on the metathorax (except the non-Costa Rican family Cephidae), a trochantellus is present, and numerous enclosed cells are discernible in the wings, including one or more anal cells in the fore wing (except in most Pergidae). While the Orussidae share most of these plesiomorphic character states with the sawflies and woodwasps, they also share several apo morphic character states with the suborder Apocrita (Gibson, 1985; N.F. Johnson, 1988; Whitfield et al., 1989; see Chapters 5 and 7). Moreover, the larval stages of Orussidae differ from all other symphytans in being parasitic or predatory rather than phy tophagous. Therefore the orussids are treated in a separate chapter (Chapter 7).
The chrysidoid families
Authors: Gauld Ian D , Hanson Paul E 
Published: November 2023

Abstract
The superfamily Chrysidoidea is a monophyletic clade that is the sister-group to the other two aculeate super families (Brothers, 1975). It comprises seven extant monophyletic families, the Bethylidae, Chrysididae, Dryinidae, Embolemidae, Plumariidae, Sclerogibbidae and Scolebythidae. The most recent and comprehensive investigation of the phylogeny of the group is the work of Carpenter (1986a) who postulated the phylogenetic relationships shown in Fig. 13.01.
The lower vespoid families
Authors: Brothers Denis J 
Published: November 2023

Abstract
The superfamily Vespoidea is almost certainly a mono phyletic clade which is the sister group of the Apoidea (Brothers, 1975; Brothers & Carpenter, 1993). Unlike the Chrysidoidea and the Apoidea, however, the Vespoidea does not appear to possess any unique synapomorphies, mainly being characterized by the reduced prepectus. It comprises ten extant mono phyletic families (Fig. 14.01). The most recent and comprehensive study of the phylogeny of the families (and some subfamilies) of Vespoidea is that of Brothers and Carpenter (1993) who re-evaluated the work of Brothers (19 75) and subsequent authors. The phylogeny shown in Fig. 14.01 represents our present best estimate of their relationships.
The Bees(Apidae)
Authors: Griswold Terry , D.Parker Frank , E.Hanson Paul 
Published: November 2023

Abstract
Diagnosis Body length 1.5 to 46.0 mm, in Costa Rica ranging from the minute stingless bee Trigonisca discolor (less than 3 mm) to the robust carpenter bee Xylocopa nautlana (more than 30 mm). Black, brown, reddish, yellow, sub-metallic, or brilliantly metallic blue, green, or coppery; a few are marked with yellow or white. Pubescence ranges from nearly absent to very long and dense, varying in colour but always having at least some plumose hairs, especially in the vicinity of the mesothoracic spiracle, the upper part of the propodeum and the lateral portions of the metanotum. Both sexes always fully winged; sexual dimorphism slight.
Ecology of South Turkana
Authors: Little Michael A , Dyson-Hudson Rada , Mccabe J Terrence 
Published: November 2023

Abstract
The territory of the Ngisonyoka section of South Turkana is a part of Turkana District, which is located in the north-west corner of Kenya and is the northernmost and largest district of Kenya’s Rift Valley Province. It is one of the driest areas of Kenya. Pratt and Gwynn (1977) classify the region as including semi-arid, arid, and very arid ecoclimatic zones. These zones are characterized by very high temperatures, and rainfall between slightly more than lO0mm/year in the very arid zone to 600mm/year or more in the semi-arid zone; and vegetation ranging from desert scrub and sparse annual grassland (very arid) to dwarf-shrub annual grassland (arid) to wooded grassland and bushland with dense stands of perennial grasses (semi-arid). Considerable woody vegetation is found in riparian groundwater areas that result from the braided drainage systems on the several plains, and in riverine forests along the Kerio and Turkwel Rivers (Coughenour et al. 1990c; Coughenour and Ellis 1993; Wyant and Ellis 1990).
Infant care and feeding
Authors: Gray Sandra J 
Published: November 2023

Abstract
Infant care and feeding practices represent, perhaps, the keystone of human adaptive strategies, since they impact both directly and indirectly on human fertility and child survival. The structure of breast-feeding in a population directly influences human fertility through its effects on the duration of postpartum amenorrhoea and on birth spacing. The structure of the weaning process influences fertility both directly, through maternal hormonal changes induced by reduced suckling, and indirectly, through its impact on infant and weanling morbidity and mortality. This chapter begins with a brief discussion of the biological, behavioral, and environmental factors which contribute to cross-cultural variation in infant care and feeding. Next, breast-feeding and weaning practices among Turkana pastoralists are examined, with particular attention to the constraints on infant feeding in the Turkana setting and to maternal strategies used to negotiate within those limits. Finally, an ecological model is presented which summarizes relationships between the infant feeding practices, the variables which influence them, and reproductive strategies among nomadic Turkana.
People and herds
Authors: Leslie Paul W , Dyson-Hudson Rada 
Published: November 2023

Abstract
Humans and livestock in Turkana are intimately interdependent. Nomadic Turkana depend on livestock for virtually all their food (Chapter 7); and livestock depend on humans for protection and regular access to resources—forage and particularly water. This means that there is a continual and close association between the densities and distributions of human and livestock populations across the landscape. Although the importance of understanding the demography of both human and livestock populations has long been recognized (Stenning 1959), demographic studies of pastoralists, especially nomadic pastoralists, have been scarce until the past decade, and studies of the population dynamics of their herds remain rare. In this chapter, we consider the relationship between the Turkana and their livestock at the population level, and provide a background for the demographic studies that form the basis for Chapters 13, 14, 15 and, to a lesser extent, 17.
Road traffic growth and the dynamics of sustainable transport policies
Authors: Goodwin Phil 
Published: November 2023

Abstract
Professor Phil Goodwin, BSc (Econ), MA, PhD, is one of Britain’.s leading experts on transport economics and policy. After taking his first degree, in economics, and a PhD in Civil Engineering (Transport Studies) at University College, London, Professor Goodwin joined the Department of Planning and Transportation of the Greater London Council in 1974. He served as Acting Head of the Public Transport Economics Section of that Department and then as Transportation Economics Advisor to the Council. In 1979, Professor Goodwin moved to Oxford, where he joined the University s Transport Studies Unit. He was appointed in 1981 to a University Readership in Transport Studies and to the Directorship of the Unit; in the following year he was elected to an Official Fellowship of Linacre College and, in 1990, to a Professorial Fellowship of the College. In 1996 Professor Goodwin returned to University College, London, to take up the appointment of Professor of Transport Policy there. He is a member of the Standing Advisory Committee on Trunk Road Assessment (SACTRA) and has advised a large number of bodies and institutiom both national and local, on transport matters. Professor Goodwin is the author of’ numerous articles and reports on transportation and gave evidence to the Royal Commission on Environmental Pollution.
Mechanistic insights into tumour angiogenesis
Authors: Bicknell Roy 
Published: November 2023

Abstract
As outlined in Chapter I there are two recognized processes by which new blood vessels are formed. These are called vasculogenesis and angiogenesis. Vasculogenesis describes the formation of new vessels from the endothelial presursors that are present in the blood islands of the developing embryo. Angiogenesis is the development of new blood vessels from pre-existing blood vessels. In the adult, all new blood vessels arise by angiogenesis.
Prognostic and predictive value of intra-tumoral microvessel density in human solid tumours
Authors: Gasparini Giampietro 
Published: November 2023

Abstract
The majority of human solid tumours are heterogeneous diseases, made up of multiple cell clones with diverse biological aggressiveness (1,2). The tumour cell heterogeneity is the result of the genomic instability (3) due to genetic alterations that may include: mutations, deletions, chromosomal rearrangements, activation of oncogenes, downregulation of tumour suppressor genes, and gene amplification (4-7). Tumour cell heterogeneity may confer different properties of growth, immunogenicity, ability to metastatize, and sensitivity to treatments to the diverse cell clones. Tumour cell genomic instability and heterogeneity are the biological basis of the clinical observation that both the outcome of the patients and their responsiveness to anti-cancer therapy may be different among tumours classified as having the same pathological or clinical stage. Thus, for several solid tumours it is difficult, by using conventional clinicopathological criteria, to assess the prognosis or the likelihood of response to a specific form of anti-cancer treatment of any single patient.