bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in the pattern of osmoregulation in the brackish water amphipod Gammarus duebeni Lilljeborg (crustacea) during embryonic development
Authors: Morritt David , Spicer John I. 
Published: June 2005

AbstractEggs of the gammarid amphipod Gammarus duebeni Lilljeborg were cultured in sterilised in vitro conditions over a range of external seawater concentrations. The osmoregulatory ability of embryos and newly hatched individuals cultured in these conditions was examined over a wide range of external concentrations (75‐1,250 mOsm·kg−1 at 15°C). For all of the developmental stages examined the isosmotic point of the periembryonic fluid, P.F. (fluid from the space between the embryo and the vitelline membrane) or haemolymph from newly hatched individuals was similar (500‐550 mOsm·kg−1). Regulation of the P.F. by early stage 2 and 3 embryos, characterised by reddening cephalothorax and limb bud development, and of the haemolymph by new hatchlings followed a hyper‐isosmotic regulation pattern. In dilute external concentrations (between 50 and 100 mOsm·kg−1) P.F./haemolymph was maintained at a concentration of approx. 400 mOsm·kg−1): This difference diminished with increasing external concentration so that at and above 500‐550 mOsm·kg−1 P.F./haemolymph and external concentrations were isosmotic. Maintenance of a hyperosmotic P.F. in dilute media maintains cell function and establishes the osmotic gradient required for the uptake of water that results in the characteristic swelling of embryos. P.F. osmolality was regulated before the appearance of the coxal gills possibly via the vitelline membrane and/or the dorsal organ. In contrast, P.F. from later, stage 5‐7 embryos (eye pigmentation and cardiovascular development but still pre‐hatch) showed a distinct hyper‐hypo‐osmotic pattern of regulation: In dilute media the P.F. was maintained at levels between 400 and 550 mOsm·kg−1, and at external concentrations above 550 mOsm·kg−1 the P.F. was less concentrated than the medium (a difference of > 350 mOsm·kg−1 in the most concentrated external media). The functional significance of this hyper‐hypo‐osmoregulatory pattern is unknown although its appearance may be associated with the appearance of the coxal gills and the subsequent degeneration of the dorsal organ. This study has demonstrated that osmoregulatory function changes with ontogeny in amphipods and that the most “complicated” pattern (hyper‐hypo‐regulation) is associated with late embryo rather than the most “complex” (adult) stage. © 1995 Wiley‐Liss, Inc.
Acquisition of nerve dependence for the formation of a regeneration blastema in amputated hindlimbs of larval Xenopus laevis: The role of limb innervation and that of limb differentiation
Authors: Filoni Sergio , Velloso Cristiana Paranhos , Bernardini Sergio , Cannata Stefano M. 
Published: June 2005

AbstractIn larval and adult urodeles and late‐stage larval anurans, blastema formation after limb amputation requires an adequate nerve supply. Experimental evidence obtained from aneurogenic limbs indicates that, in urodeles, the acquisition of nerve dependence during embryonic development is due to the “addiction” of limb tissues to factors released by the ingrowing nerves rather than to limb differentiation. The aim of this work was to establish whether, in the toad Xenopus laevis, nerve‐dependence for blastema formation after hindlimb amputation, which is acquired gradually during larval development and becomes complete at stage 57 is due to limb innervation or to limb differentiation.Two series of experiments were carried out. In the first series, limb differentiation was inhibited by treating the larvae with an anti‐thyroid drug, and innervation was maintained for an interval much longer than that normally required for development from nerve‐independent stages to stage 57. In the second series, the limb was caused to differentiate in the absence of nerves by maintaining the limbs denervated. Limb differentiation was often accelerated by treating early‐stage larvae with thyroxine or by grafting early‐stage limbs onto denervated limbs of late larvae, which, being near metamorphic climax, possessed high levels of circulating thyroid hormones.Results showed that in the first series of experiments the denervated limbs formed regeneration blastemas after amputation, but in the second series they did not. It was therefore concluded that the acquisition of nerve dependence for blastema formation in larval Xenopus laevis is not directly imposed by factors released by the nerve fibers, but is strongly related to differentiation of limb tissues. © 1995 Wiley‐Liss, Inc.
Extrusion of microtubule doublet outer dense fibers 5‐6 associating with fibrous sheath sliding in mouse sperm flagella
Authors: Si Yuming , Okuno Makoto 
Published: June 2005

AbstractOur previous experiments (Si and Okuno [1993a] Exp. Cell Res., 208:170–174) provided evidence that the fibrous sheath (FS) slid headward to middle piece in the activated mouse sperm flagellum when doublet microtubules together with their outer dense fibers (ODFs) extruded from the axoneme. Of the extruded doublet‐ODFs, however, which one was responsible for the FS sliding remained unresolved. The present study demonstrated that the FS sliding and the order of doublet‐ODFs extrusion in mouse sperm flagella were trypsin concentration dependent. Under the condition of mild trypsinization (0.1 μg/ml), only doublet‐ODFs 4, 5‐6 (doublet‐ODFs 5 and 6 were always paired), and 7 extruded from the axoneme. Furthermore, the extrusion of doublet‐ODFs 5‐6 was identified to precede doublet‐ODFs 4 and 7, and was considered the candidate responsible for FS sliding. In contrast, the high‐concentration trypsinization (4 μg/ml) led to extrusion of doublet‐ODFs 1, 2, and 9 following doublet‐ODFs 4, 5‐6, and 7. FS sliding, however, did not occur. © 1995 Wiley‐Liss, Inc.
Peptidergic and adrenergic innervation of the lachrymal gland in the euryhaline turtle, Malaclemys terrapin
Authors: Belfry C. Susan , Cowan F. Brian M. 
Published: June 2005

AbstractThe controlling factors of lachrymal gland secretions were examined in the euryhaline turtle, Malaclemys terrapin. Histochemical and immunocytochemical methods were used to localize some of the possible neurotransmitters involved.There was no immunoreactivity to choline acetyltransferase, the enzyme synthesizing acetyl‐choline, nor did the histochemical technique for acetylcholinesterase produce positive results. Immunofluorescence and immunoperoxidase labels revealed vasoactive intestinal peptide (VIP)‐ and neuropeptide Y (NPY)‐like immunoreactivity in high concentrations surrounding the secretory tubules and ducts. Substance P produced a weak immunoreactivity in the interstitial space surrounding the ducts. Dopamine β‐hydroxylase, the enzyme synthesizing norepinephrine and epinephrine, was localized around the blood vessels. Immunogold labeling confirmed the presence of VIP‐ and NPY‐like reactivity in nerve varicosities close to the basement membrane of the secretory epithelium, and double‐labeling showed VIP and NPY are co‐localized within the same nerve terminals.The results suggest that the secretory epithelium may be primarily under peptidergic control while the vascular system is under adrenergic control. This is possibly a new pattern of innervation for exocrine glands and may be related to the particular function of this salt gland in an euryhaline turtle. © 1995 Wiley‐Liss, Inc.
Proteins of Crustacean exoskeleton: IV. Partial amino acid sequences of exoskeletal proteins from the Bermuda land crab, Gecarcinus lateralis, and comparisons to certain insect proteins
Authors: Kumari S. Sindhu , Willis Judith H. , Skinner Dorothy M. 
Published: June 2005

AbstractAs in all decapod Crustacea, the exoskeleton of the land crab Gecarcinus lateralis consists of four layers. Prior electrophoretic analysis of proteins extracted from these layers revealed an abundance of small Mr proteins with acidic pIs as are found in insect cuticle (O'Brien et al. [1991] Biol. Bull., 181:427–441). Further, immunological cross‐reactivity between crab exoskeletal proteins and insect cuticular proteins has been demonstrated (Kumari and Skinner [1993] J. Exp. Zool., 265:195–210). Partial amino acid sequences of a number of proteins from the four exoskeletal layers are described here. Proteins were electrophoresed on two‐dimensional (2D) gels, transferred to polyvinylidene difluoride (PVDF) membranes, and stained; individual spots were recovered and their N‐termini were sequenced. In addition, a 14‐kDa protein (pI =5.4) from membranous layer (ML14) was eluted from 2D gels and digested with endoproteinase Lys‐C; N‐termini of its constituent peptides were sequenced.The two epicuticular proteins differed from each other. Three proteins with identical electrophoretic mobility isolated from exocuticle, endocuticle, and membranous layer appeared to have identical N termini, while another electrophoretically identical set from the three layers appeared identical with each other but differed in three positions from the first set. Two proteins from the membranous layer both had a mass of 25 kDa but different isoelectric points. Their sequences were indistinguishable from each other but clearly distinct from another membranous layer protein. Another distinct sequence was found in a 14‐kDa protein from endocuticle, while a less acidic pair of 14‐kDa proteins from endocuticle and membranous layer were quite similar to one another. The three internal peptide fragments from ML14 were distinct, but one had regions similar to the ML14 N terminus. One crab exoskeletal protein sequence was similar to some structural proteins of vertebrates, whereas others had motifs found in insect cuticular proteins. The sequence similarities identified did not account for the antibody cross‐reactivity. © 1995 Wiley‐Liss, Inc.
A role for gene therapy in mental retardation
Authors: Moser Hugo W. 
Published: June 2005

AbstractIt is likely that gene therapy will be of most benefit in the single gene disorders that cause severe mental retardation. Reviews published in this issue focus on a number of these disorders in which vector development and preclinical trials or in vivo and ex vivo gene therapy are already in progress for urea cycle disorders, Lesch‐Nyhan disease, Gaucher disease, and phenylketonuria. On the other hand it is unlikely that gene therapy will hold much promise for the treatment of mild mental retardation which accounts for more than 80% of all cases of mental retardation. Here there is a strong environmental influence and early intervention and educational programs carry significant benefit. © 1995 Wiley‐Liss, Inc.
Gene therapy in mental retardation: Ethical considerations
Authors: Fletcher John C. 
Published: June 2005

AbstractThis article discusses resources in ethics for investigators who will pursue gene therapy for disorders that cause mental retardation: literature on the ethical principles that ought to guide clinical research, norms and practices of human experimentation, paradigm cases for human gene therapy, and professional integrity. I review major ethical considerations in the process of planning and conducting experiments, including benefits to subjects, the safety of subjects, voluntary informed assent of soem children and the permission of parents of children with retardation, as well as concerns for fairness in the selection of subjects. From a perspective of social justice, I criticize the potential of proposals for interventions to enhance mental abilities and argue for restraint and long‐range openness toward human germ‐line therapy to prevent genetic disorders. Depending on technical developments, gene therapy may provide humans with great benefits, including the prevention of the mental retardation caused by some genetic disorders. It is the responsibility of scientists and public review bodies to implement and monitor guidelines and safeguards so that human gene therapy can be fully tested and its benefits fairly distributed to those whose need and opportunity to benefit are greatest. © 1995 Wiley‐Liss, Inc.
Lesch‐Nyhan disease as a model for central nervous system directed gene therapy
Authors: Friedmann Theodore 
Published: June 2005

AbstractAs a model disease for the development of suitable gene transfer techniques and their physiological and neurological testing, Lesch‐Nyhan syndrome (LNS) provides important advantages, including the availability of a well‐characterized genetic defect and candidate metabolic targets, as well as a relevant animal model and appropriate gene transfer vectors. On the other hand, the serious gap between the level of characterization of the underlying genetic defects and the resulting neuropathological effects is one of several major impediments to the development of gene therapy. However, the dopamine defect that occurs in LNS may be much more amenable to genetic manipulation than is the deficiency of hypoxanthine guanine phosphoribosyltransferase. A genetic approach to the correction of this intermediate biochemical aberration, which probably is responsible for at least some neurological signs and symptoms of LNS, may be within reach of even the currently imperfect tools of gene therapy. Exploration of this possibility, along with other studies, is likely to lead, slowly but surely, to definition of the conditions under which the genetic and neurophysiological aberrations of LNS will be susceptible to a degree of correction that is not possible by drug therapy alone. © 1995 Wiley‐Liss, Inc.
Prospects for gene therapy in ornithine carbamoyltransferase deficiency and other urea cycle disorders
Authors: Robinson Michael B. , Batshaw Mark L. , Ye Xuehai , Wilson James M. 
Published: June 2005

AbstractAlthough individually inborn errors of metabolism are rare, collectively they contribute significantly to morbidity and mortality in the pediatric age group. There are several reasons why, out of these inborn errors of metabolism, urea cycle disorders have emerged as potentially good candidates for the development of gene therapy. Studies have initially focused on ornithine carbamoyltransferase (OCT) deficiency in part because there are mouse models of this disease and in part because this disease is particularly resistant to current therapies. Both in vivo and ex vivo approaches to gene therapy are being developed for the treatment of urea cycle disorders. Ex vivo gene therapy is appealing because of the long‐term expression that can be achieved, but there are clear limitations to this approach. In vivo gene therapy using adenoviral vectors is attractive for several reasons, including the fact that the virus can be administered by intravenous injection, the high levels of expression observed after a single injection, and the rapidity of that expression. Studies of transgene expression in the mouse models of OCT deficiency (OCTD) have been encouraging, but have also provided evidence that the immune system may be involved in mediating two limiting aspects of this technology, transient gene expression and inflammation. Although deletions in adenoviral early genes should limit adenoviral late gene expression and subsequent viral replication, there is in vitro and in vivo evidence of late gene expression after infection with adenoviruses deleted of some of the early genes. Future studies will focus on systematically defining the components of the virus that are recognized by the immune system and mutating these gene products. The development of an approach to gene therapy that safely, stably, and efficiently transduces gene expression holds the promise of revolutionizing the treatment of inborn errors of urea synthesis. © 1995 Wiley‐Liss, Inc.
Gaucher disease: A tale of two species
Authors: McKinney Cindy E. , Sidransky Ellen , Lamarca Mary E. , Riviere Isabelle , Holleran Walter M. , Martin Brian M. , Willemsen Rob , Mulligan Richard C. , Ginns Edward I. 
Published: June 2005

AbstractGaucher disease, the result of inherited deficiency of glucocerebrosidase, is the most common lysosomal storage disease. No naturally occurring animal models are available for study of its pathophysiology or the development of new therapeutic strategies such as gene therapy. We describe an approach to gene targeting in embryonic stem cells to “knock out” glucocerebrosidase activity and generate a mouse line having the phenotype of severely affected infants with type 2 Gaucher disease. We also discuss an experiment in gene therapy using lethally irradiated mice that are reconstituted with murine fetal liver hematopoietic cells transduced with retrovirus encoding human glucocerebrosidase. Analyses of these animals show production of active human glucocerebrosidase in lysosomes of macrophages for at least 12 months after transplantation. © 1995 Wiley‐Liss, Inc.
Functional assessment and intervention in community settings
Authors: Sprague Jeffrey R. , Horner Robert H. 
Published: June 2005

AbstractFunctional assessment has emerged as an important strategy for designing effective interventions for serious problem behavior. A comprehensive functional assessment identifies the behavior of concern, stimuli correlated with the onset and maintenance of the behavior, features of the setting in which the behavior occurs, and behaviors (typically communication) that may serve to replace the problem behavior. We present a historical and modern context for functional assessment and, in juxtaposition to this, discuss the purposes of functional assessment as a tool for researchers and practitioners. We review the current range of functional assessment applications, emphasizing the strengths and limitations of each; propose needed extensions of existing functional assessment methods; and discuss the critical role of functional assessment in designing effective community‐based behavioral interventions. © 1995 Wiley‐Liss, Inc.
Bio‐behavioral diagnosis and treatment of self‐injury
Authors: Mace F. Charles , Mauk Joyce E. 
Published: June 2005

AbstractSelf‐injurious behavior(SIB) in individuals with mental retardation is a severe behavioral disorder that has significant social and medical consequences. Although considerable research evidence indicates that SIB can be maintained by either environmental contingencies or biologic conditions, integrative diagnostic and treatment models have yet to be developed. We have piloted a bio‐behavioral diagnostic and treatment model to classify and subtype cases of SIB, leading to the selection of specific behavioral or pharmacologic treatments. A functional analysis defines SIB as operant, possibly biologic, or mixed operant and possibly biologic. Subtyping within these classes is based on the delineation of specific operant functions and the clinical characteristics of the individual patient. Our preliminary research suggests that this empirical decision‐making model can lead to specific treatments that are effective and that reduce the incidence of nonresponders to behavioral intervention and medication. © 1995 Wiley‐Liss, Inc.
Opiate mechanisms in self‐injury
Authors: Sandman Curt A. , Hetrick William P. 
Published: June 2005

AbstractSelf‐injuring behavior is among the most unmanageable, expensive, destructive, and unpredictable behaviors exhibited by human beings. Interventions that included punishment or restraint were among the most successful for acute control of SIB. Both painful shock and restraint stimulate release of the body's own opiates into the bloodstream. These powerful agents, which possess analgesic and addictive properties, are more potent than morphine. Based on these observations, two versions of the opiate hypothesis have evolved to explain SIB. The analgesia hypothesis suggests that high‐circulating levels of β‐endorphin (βE) in individuals with SIB reduces the perception of pain. With the experience of pain reduced, individuals inflict self‐harm as a form of stimulation. The addiction hypothesis presumes that the release of opiates after “pain” or SIB produces pleasure. As a consequence, individuals exhibiting SIB become addicted to their own opiate system. The strongest link between SIB and the opiate hypotheses is the finding that opiate receptor blockers attenuate and sometimes eliminate this behavior. In addition to providing a possible treatment for some SIB individuals, these findings suggest that a specific opiate system, βE and mu receptor, is disregulated (by elevated levels of opiates, abnormally sensitive opiate receptors, or uncoupling of co‐released peptides). Recent studies have found that βE was elevated after an SIB episode, but that co‐released peptides such as ACTH were not. Selective release of βE after SIB provides evidence that endogenous opiates have a direct association with SIB. This association supports speculation that endogenous opiates maintain SIB. © 1995 Wiley‐Liss, Inc.
Molecular and clinical correlations in fragile X syndrome
Authors: Hagerman Randi Jenssen 
Published: June 2005

AbstractSince the advent of DNA testing after 1991, variations in molecular patterns, such as the CGG expansion length, mosaicism, partial methylation, and X‐inactivation, have been correlated with the degree of phenotypic involvement in fragile X syndrome. Although some reports conflict it appears that a low CGG repeat number within the full mutation range or lack of methylation, whether almost complete or partial, is associated with only mild involvement in males. A subgroup of individuals with the premutation may also demonstrate mild problems associated with fragile X syndrome. This article reviews preliminary studies of FMRP expression and discusses a hypothesized correlation between FMRP expression and phenotypic involvement. Molecular and clinical correlations are advancing our understanding of the mild range of phenotypic involvement in fragile X syndrome, which involves learing disabilities and emotional difficulties, but not mental retardation. © 1995 Wiley‐Liss, Inc.
An animal model for fragilex syndrome
Authors: Willems Patrick J. , Reyniers Edwin , Oostra Ben A. 
Published: June 2005

AbstractAlthough the fragile X gene (FMR1) was isolated more than four years ago, little is known about its physiologic function and the pathological mechanisms that lead to the abnormalities observed in fragile X patients. To provide more insight into the physiologic role of FMR1, we have developed a transgenic mouse with a loss‐of‐function (Knockout) mutation in the FMR1 gene using homologous recombination in embryonic stem cells. The mutant mice lack normal FMR1 mRNA and protein, as is also the case in human fragile X syndrome. The mice show enlarged testes and impaired performance in cognitive function tests, a clinical picture very similar to that of human patients. As a consequence, this animal model might be useful in elucidating the physiologic function of FMR1 and the pathological mechanisms that lead to mental retardation and behavioral abnormalities in fragile X syndrome. Experimental drug treatment can now be tried to ameliorate the congnitive function and behavior of affected mice and, if these experiments are successful, human trials can be initiated. Furthermore, gene therapy experiments by introduction of a foreign FMR1 gene into mutant mice can now be begun. © 1995 Wiley‐Liss, Inc.