bluuebunny/crossref_metadata_2025_split huggingface dataset:
A developmental approach to understanding Fragile X syndrome in females
Authors: Keysor Cynthia S. , Mazzocco Michèle M.M. 
Published: August 2002

AbstractThe psychological phenotype of females with fragile X syndrome (FraX) is discussed, focusing primarily on empirical findings over the past decade and on studies of probands with the full mutation (FM). A developmental approach is used to help characterize specific patterns of cognitive, neuropsychological, social, emotional, and behavioral functioning across the lifespan of females with FraX. Approximately half of females with the syndrome present with cognitive abilities that fall in the borderline to mentally retarded range, and the remaining females with average intellectual functioning may experience relative deficits in math achievement and problems with attention and executive functioning. Reports of socio‐emotional functioning are somewhat inconsistent, due in part, perhaps, to methodological differences in study design. To date, much of what we understand about the psychological phenotype of FraX is based on cross‐sectional studies of girls and women with the disorder. Symptoms associated with shyness, and social anxiety and avoidance have been reported in some school‐age, adolescent, and adult females with FraX. Only recently have efforts begun to identify the developmental trajectory of FraX in infants and toddlers. There is a void of information specific to these developmental periods. Identifying key deficits in cognitive and socio‐emotional functioning has important implications for early detection and intervention for girls with FraX. Directions for future research are discussed. Microsc. Res. Tech. 57:179–186, 2002. © 2002 Wiley‐Liss, Inc.
Membrane traffic in myelinating oligodendrocytes
Authors: Krämer Eva‐Maria , Schardt Anke , Nave Klaus‐Armin 
Published: August 2002

AbstractIn the central nervous system (CNS), the myelin sheath is synthesised by oligodendrocytes as a specialised subdomain of an extended plasma membrane, reminiscent of the segregated membrane domains of polarised cells. Myelination takes place within a relatively short period of time and oligodendrocytes must have adapted membrane sorting and transport mechanisms to achieve such a high rate of myelin synthesis and to maintain the unique organisation of the myelin membrane. In adult life, maintenance of the functional myelin sheath requires a carefully orchestrated balance of myelin synthesis and turnover. Imbalance in these processes may cause dys‐ or demyelination and disease. This review summarises what is currently known about myelin protein trafficking and mistrafficking in oligodendrocytes. We also present data demonstrating distinct transport pathways for myelin structural proteins and the expression of SNARE proteins in differentiating oligodendrocytes. Myelinating glial cells may well serve as a model system for studying general aspects of membrane trafficking and organisation of membrane domains. Microsc. Res. Tech. 52:656–671, 2001. © 2001 Wiley‐Liss, Inc.
Expression of Leu‐19 (CD56, N‐CAM) and nitric oxide synthase (NOS) I in denervated and reinnervated human skeletal muscle
Authors: Gosztonyi Georg , Naschold Ulrich , Grozdanovic Zarko , Stoltenburg‐Didinger Gisela , Gossrau Reinhart 
Published: August 2002

AbstractNeural cell adhesion molecule (N‐CAM, Leu‐19, CD 56) expression appears during muscle fiber regeneration and after denervation. Sarcolemma‐associated nitric oxide synthase (NOS) I, however, disappears from denervated myofibers. The dynamics of expression of both proteins were studied in 5 cases of acute/subacute denervation, 28 cases of chronic denervation with and without collateral reinnervation, 5 cases of the intermediate type spinal muscular atrophy (SMA 2), and in 2 normal biopsies. NOS I and its NADPH diaphorase (NADPHd) activity disappeared from the sarcolemma region shortly after denervation, and before the appearance of denervation atrophy. N‐CAM was found diffusely distributed in the sarcoplasm at the most severe phase of denervation atrophy in the majority of highly atrophic fibers. During reinnervation, NOS I expression remained absent and in part of the cases the target/targetoid phenomenon appeared. In parallel with the increase in volume of the reinnervated muscle fibers, the intensity of N‐CAM immunoreactivity decreased progressively. After full restitution of muscle fiber caliber, the target/targetoid phenomenon and N‐CAM immunostaining disappeared completely, and, finally, NOS I reappeared in the sarcolemma region. The sarcolemmal expression of dystrophin and dystrophin‐associated proteins was unchanged during denervation. NOS I was completely absent in children with SMA 2, since the protein does not appear before 5 years of age in skeletal muscle, while N‐CAM was very intensely expressed in the sarcoplasm of highly atrophic denervated muscle fibers. In conclusion, this study suggests that innervation is an important factor for selective gene expression and positioning of NOS I and N‐CAM in skeletal muscle and gives practical information for the assessment of the phase and developmental stage of the denervation and reinnervation process. Microsc. Res. Tech. 55:187–197, 2001. © 2001 Wiley‐Liss, Inc.
Sex from W to Z: Evolution of vertebrate sex chromosomes and sex determining genes
Authors: Marshall Graves Jennifer A. , Shetty Swathi 
Published: August 2002

AbstractSex determination in major vertebrate groups appears to be very variable, including systems of male heterogamety, female heterogamety and a variety of genetic and environmental sex determining systems. Yet comparative studies of sex chromosomes and sex determining genes now suggest that these differences are more apparent than real. The sex chromosomes of even widely divergent groups now appear to have changed very little over the last 300+ million years, and even independently derived sex chromosomes seem to have followed the same set of evolutionary rules. The sex determining pathway seems to be extremely conserved, although the control of the genes in this pathway is vested in different elements. We present a scenario for the independent evolution of XY male heterogamety in mammals and ZW female heterogamety in birds and some reptiles. We suggest that sex determining genes can be made redundant, and replaced by control at another step of a conserved sex determining pathway, and how choice of a gene as a sex switch has led to the evolution of new sex chromosome systems. J. Exp. Zool. 290:449–462, 2001. © 2001 Wiley‐Liss, Inc.
South African regional industrial policy: from border industries to spatial development initiatives
Authors: Hartzenberg Trudi 
Published: August 2002

AbstractRegional industrial development has been the focus of a number of very specific policy initiatives in South African since the 1960s. Until the end of the 1980s these initiatives were driven by political imperative: to develop the homeland areas and to stem migration to South Africa's cities. They failed on both counts. In the early 1990s, industrial policy was markedly less focused on location. However more recently the Spatial Development Initiatives (SDI) and Industrial Development Zone (IDZ) programmes have both involved the identification of industrial locations and used incentives to encourage firms to locate in these areas. The SDI programme has specifically taken South African regional industrial policy into the southern African region with its cross‐border development corridors.The paper questions the underlying rationale for South Africa's regional industrial policy, and in particular the role of incentives in influencing firm‐level decisions, including their location decisions. The tentative conclusion is that there is no reason to suppose that the South African government could or can do better than the market in directing firm‐level location decisions, and that industrial policy incentives may be far less important to the firm than macroeconomic and market conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Variation in eggshell characteristics and in intrauterine egg retention between two oviparous clades of the lizard lacerta vivipara: insight into the oviparity–viviparity continuum in squamates
Authors: Heulin Benoit , Ghielmi Samuele , Vogrin Nusa , Surget‐Groba Yann , Guillaume Claude Pierre 
Published: August 2002

AbstractThe concept of the oviparity–viviparity continuum refers to the wide range in the length of intrauterine egg retention and, hence, in the stage of embryonic development at oviposition existing in squamates. The evolutionary process underlying this continuum may involve not only a lengthening of egg retention in utero, but also a marked reduction in the thickness of the eggshell. The idea that there may exist a negative correlation between the developmental stage reached by the embryo at oviposition and the eggshell thickness within squamates, although supported by the comparison of oviparous vs. viviparous species, has seldom been evaluated by comparing eggshell thickness of oviparous forms with different lengths of intrauterine egg retention. Eggs of two distinct oviparous clades of the lizard Lacerta vivipara were compared. The eggs laid by females from Slovenian and Italian populations have thicker eggshells, contain embryos on average less developed at the time of oviposition, and require a longer incubation period before hatching than the eggs laid by females from French oviparous populations. Our data and several other examples available from the literature support the idea that the lengthening of intrauterine retention of eggs and the shortening of the subsequent external incubation of eggs are associated with reduction in the thickness of the eggshell, at least in some lineages of oviparous squamates. The current hypotheses that may account for this correlation are presented and a few restrictions and refinements to those hypotheses are discussed. In particular, other changes, such as increased vascularization of the oviduct and of the extraembryonic membranes, may play the same role as the decrease of eggshell thickness in facilitating prolonged intrauterine egg retention in squamates. Future studies should also consider the hypothesis that the length of intrauterine retention might directly depend on the extent of maternal–fetal chemical communication through the eggshell barrier. J. Morphol. 252:255–262, 2002. © 2002 Wiley‐Liss, Inc.
Vascularization of the brains of the Atlantic and Pacific hagfishes, Myxine glutinosa and Eptatretus stouti: A scanning electron microscope study of vascular corrosion casts
Authors: Cecon Stephan , Minnich Bernd , Lametschwandtner Alois 
Published: August 2002

AbstractThe microvascularization of the brains of the hagfishes, Myxine glutinosa L. and Eptatretus stouti, were studied by scanning electron microscopy (SEM) of microvascular corrosion casts. Sections of these casts were used to determine the vascular territories of defined brain areas. Histological serial sections (10 μm) of the brains served for correlation of findings. Analysis of the microvascular casts of both species revealed that the blood supply to and from these brains arose ventrally and dorsally, respectively. Neither species possesses an arterial circle (Circulus Willisi) and both have similar microvascular patterns. The only difference between Myxine and Eptatretus was that the posterior cerebral artery in Myxine divides into mesencephalic and rhombencephalic branches, and in Eptatretus a third branch, termed telencephalic branch, arises from the posterior cerebral artery. 3D‐morphometry revealed that luminal diameters of: 1) intracerebral arteries and arterioles range from 35.11 ± 5.66 μm (mean ± SEM) in the hypothalamus to 92.69 ± 14.48 μm in the thalamus; 2) capillaries range from 17.8 ± 0.44 μm in the olfactory bulb to 21.70 ± 0.87 μm in the basal ganglia; and 3) intracerebral venules and veins range from 49.38 ± 4.17 μm in the hypothalamus to 75.58 ± 6.59 μm in the rhombencephalon. Interbranching distances of arteries and arterioles range from 179.19 ± 11.32 μm in the optic tectum to 235.19 ± 94.64 μm in the hypothalamus. Capillaries range from 91.07 ± 6.22 μm in the hypothalamus to 116.15 ± 9.45 μm in the thalamus, and venules and veins range from 137.30 ± 18.11 μm in the hypothalamus to 189.83 ± 17.47 μm in the optic tectum. Intervascular distances range from 70.58 ± 3.58 μm in the olfactory bulb to 89.52 ± 5.74 μm in the optic tectum. Branching angles of arteries and arterioles range from 38.39 ± 10.9° in the olfactory bulb to 100.73 ± 9.4° in the optic tectum, and the branching angles of capillaries range from 74.40 ± 5.42° in the optic tectum to 90.24 ± 4.66° in the olfactory bulb. Finally, the branching angles of the venules and veins range from 67.84 ± 6.83° in the tegmentum of the mesencephalon to 92.30 ± 6.35° in the optic tectum. J. Morphol. 253:51–63, 2002. © 2002 Wiley‐Liss, Inc.
Morphological changes in the efferent ducts during the main phases of the reproductive cycle of birds
Authors: Aire Tom A. 
Published: August 2002

AbstractThe changes that take place in the efferent ducts during the major phases of the reproductive cycle of birds were studied morphologically using standard histological, morphometric, and ultrastructural methods in prepuberal, sexually mature and sexually active, and sexually mature but sexually inactive domestic fowl (Gallus domesticus), drake (Anas platyrhynchos), and guinea fowl (Numida meleagris). Profound structural and dimensional changes occurred in both segments (proximal and distal) of the efferent ducts and, in particular, in the nonciliated (Type I) cell of the proximal duct of sexually mature but inactive birds. The subapical tubulovacuolar system was markedly atrophic in nonciliated (Types I and II) cells and the numerous round dense globules of Type I cells that normally occurred in sexually active birds were replaced by fewer and more pleomorphic bodies containing lipofuscin granules in sexually resting birds. Lipid droplets, few and extremely large in inactive drakes but numerous and smaller in size in guinea fowls and domestic fowls, occurred in the Type I cell at both infra‐ and supranuclear levels of resting but not in prepuberal or sexually active birds. Ciliated cells in both segments of the ducts exhibited fewer and less profound phase‐dependent changes ultrastructurally. Generally, the Type I cells of the proximal efferent duct appeared to be more sensitive to androgen deprivation than the Type II cell of the distal efferent duct or ciliated cells in both ducts. These morphologically phase‐dependent features of the efferent ducts of birds may be used, together with or independent of testicular changes, in the determination of the status of the testis and epididymis of a male bird with regard to the reproductive cycle, especially in seasonally breeding species. J. Morphol. 253:64–75, 2002. © 2002 Wiley‐Liss, Inc.
Cine MRI using steady state free precession in the radial long axis orientation is a fast accurate method for obtaining volumetric data of the left ventricle
Authors: Bloomer Timothy N. , Plein Sven , Radjenovic Aleksandra , Higgins David M. , Jones Timothy R. , Ridgway John P. , Sivananthan Mohan U. 
Published: August 2002

AbstractIn this study we assessed the use of a steady state free precession (SSFP) cine sequence in a series of radially orientated long axis slices for the measurement of left ventricular volumes and mass. We validated the radial long axis approach in phantoms and ex vivo porcine hearts and applied it to normal volunteers and patients using the SSFP and turbo gradient‐echo (TGE) sequences. High quality images were obtained for analysis, and the measured volumes with radial long axis SSFP sequence correlated well with short axis TGE and SSFP volumes (r > 0.98). The best interobserver agreement for left ventricular volumes was obtained using SSFP in the long axis radial orientation (variability < 2.3%). We conclude that this combination of sequence and scan orientation has intrinsic advantages for image analysis due to the improved contrast and the avoidance of errors associated with the basal slice in the short axis orientation. J. Magn. Reson. Imaging 2001;14:685–692. © 2001 Wiley‐Liss, Inc.
Diffusion‐weighted imaging of the spinal cord: Interleaved echo‐planar imaging is superior to fast spin‐echo
Authors: Bammer Roland , Augustin Michael , Prokesch Rupert W. , Stollberger Rudolf , Fazekas Franz 
Published: August 2002

AbstractPurposeTo compare and evaluate two novel diffusion‐weighted sequences, based either on fast spin‐echo (FSE) or interleaved echo‐planar imaging (EPI) methods, as potential tools for investing spinal cord abnormalities.Materials and MethodsFollowing recent improvements, both interleaved EPI (IEPI) and FSE techniques could be alternative approaches for rapid diffusion‐weighted imaging (DWI). Therefore, a navigated diffusion‐weighted multishot FSE sequence and a fat‐suppressed navigated diffusion‐weighted IEPI sequence with local shimming capabilities were tested. Both methods were compared in a consecutive series of five healthy volunteers and five patients with suspected intramedullary lesions. The sequences were graded qualitatively as either superior, inferior, or equal in quality, and also quantitatively by measuring the amount of ghosting artifacts in the background. Quantitative measurements of the diffusion coefficients within the spine were included.ResultsThe overall image quality of IEPI was superior to FSE. Two out of five FSE scans were rated with poor image quality, whereas all IEPI scans were of sufficient quality. The ghosting levels ranged from approximately 3.3% to 6.2% for IEPI and from approximately 7.5% to 18.9% for FSE. Diffusion coefficients measured in healthy volunteers were similar for both IEPI and FSE, but showed higher fluctuations with the FSE technique.ConclusionDespite potential advantages of FSE, the IEPI technique is preferable for DWI applications in the spinal cord. J. Magn. Reson. Imaging 2002;15:364–373. © 2002 Wiley‐Liss, Inc.
Comparison of the threshold for peripheral nerve stimulation during gradient switching in whole body MR systems
Authors: Den Boer Jacques A. , Bourland Joe D. , Nyenhuis John A. , Ham Cornelis L.G. , Engels Johan M.L. , Hebrank Franz X. , Frese Georg , Schaefer Daniel J. 
Published: August 2002

AbstractPurpose:To compare thresholds for peripheral nerve stimulation from gradient switching in whole body magnetic resonance (MR) equipment of different design.Materials and Methods:Threshold data obtained in three experiments were reformatted into a single joint data set describing thresholds for anterio‐posterior (AP) gradient orientation and Echo Planar Imaging (EPI) waveforms with bipolar ramp times between 0.07 and 1.2 ms. Reformatting included the use of: a) the rate of change of the maximum field in the patient space as a measure of gradient output, b) lowest observable thresholds, c) lognormal distribution of thresholds, and d) equal standard deviation (SD) of all samples.Results:The joint data fit a hyperbolic threshold function. The residues were not significantly different between experiments.Conclusion:When expressed in appropriate format, the thresholds for peripheral nerve stimulation in volunteers for whole body MR equipment can be described with a hyperbolic threshold curve with rheobase 18.8 ± 0.6 Tesla/second and chronaxie 0.36 ± 0.02 milliseconds. J. Magn. Reson. Imaging 2002;15:520–525. © 2002 Wiley‐Liss, Inc.
Contrast‐enhanced coronary MR angiography: Relationship between coronary artery delineation and blood T1
Authors: Zheng Jie , Li Debiao , Cavagna Friedrich M. , Harris Katherine , Klocke Francis J. , Maggioni Fabio , Carr James , Simonetti Orlando , Laub Gerhard , Finn J. Paul 
Published: August 2002

AbstractContrast‐enhanced coronary angiography has become an important technique for magnetic resonance (MR) coronary artery imaging. However, the relationship between the quality of the coronary artery images and blood T1 has not yet been fully explored. In this paper, we assessed this relationship in an animal model by using a prototypical blood pool agent. With accumulated injections of this agent, the blood T1 would be maintained at different levels. The measured blood T1 values in vivo were 147 ± 3, 82 ± 6, 48 ± 4, 40 ± 3, and 30 ± 8 msec (N = 7). Fixed and variable flip angle schemes were used in coronary artery imaging. The signal to noise ratios (SNR) of coronary arteries were measured and the image quality was assessed. It was found that blood T1 less than 80 msec might be desired. No statistically significant difference was observed between two flip angle schemes. There was better vessel definition using variable flip angle at blood T1 lower than 50 msec. Understanding this relationship may be beneficial to optimizing image protocol and/or design of blood pool contrast agents for contrast‐enhanced coronary angiography. J. Magn. Reson. Imaging 2001;14:348–354. © 2001 Wiley‐Liss, Inc.
Probing protein stabilization by glycerol using electrospray mass spectrometry
Authors: Grandori Rita , Matecko Irena , Mayr Petra , Müller Norbert 
Published: August 2002

AbstractThis study shows that electrospray ionization mass spectrometry (ESI‐MS), combined with a heated turbo ion‐spray interface, allows monitoring protein stabilization by glycerol in solution. Measurements obtained with the two proteins lysozyme and cytochrome c are presented. The observed mass‐to‐charge (m/z) distributions reveal the stabilizing effect of the additive on the protein conformations against temperature and acid‐induced unfolding, as well as against denaturation by acetonitrile. The data obtained with lysozyme allow detection of minor conformational changes upon glycerol addition to the native protein, and suggest that the protein structure in the presence of the additive is slightly compressed compared with its state in water. This result corroborates previous evidence obtained by nuclear magnetic resonance. It is also shown that analysis of the m/z distributions obtained by ESI‐MS can lead to detection of partially folded and partially populated states in protein samples. Copyright © 2001 John Wiley & Sons, Ltd.
State of HBV DNA in HBsAg‐negative, anti‐HCV‐positive hepatocellular carcinoma: Existence of HBV DNA possibly as nonintegrated form with analysis by Alu‐HBV DNA PCR and conventional HBV PCR
Authors: Kawai Shigenobu , Yokosuka Osamu , Imazeki Fumio , Maru Yasushi , Saisho Hiromitsu 
Published: August 2002

AbstractThe role of hepatitis B virus (HBV) in carcinogenesis of hepatitis B surface antigen (HBsAg)‐negative, anti‐hepatitis C virus (anti‐HCV)‐positive hepatocellular carcinoma (HCC) remains unknown. To investigate the state of HBV DNA in such HCC, HBV DNA was examined by polymerase chain reaction (PCR) between HBV DNA and human Alu sequence (HBV‐Alu PCR), which could detect integrated form of HBV DNA only, and by conventional HBV PCR, which could detect both integrated and episomal forms of HBV DNA. In all the 17 HBsAg‐positive HCC, HBV DNA was detected by both HBV‐Alu PCR method and conventional HBV PCR method. By contrast, in HBsAg‐negative, anti‐HCV‐positive cases, HBV DNA was detected in 10 of 21 (47.6%) by conventional HBV PCR and in none of 21 (0%) by HBV‐Alu PCR method. Thus, integrated form of HBV DNA was not found in most HbsAg‐negative, anti‐HCV‐positive HCC in the current study. The role of episomal form of HBV DNA requires further investigation of its involvement in the process of the development of HBsAg‐negative, anti‐HCV‐positive HCC. J. Med. Virol. 64:410–418, 2001. © 2001 Wiley‐Liss, Inc.