bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear and microtubule reorganization in nuclear‐transferred bovine embryos
Authors: Shin Mi‐Ra , Park Sang‐Wook , Shim Hosup , Kim Nam‐Hyung 
Published: August 2002

AbstractWe studied the nuclear and microtubule dynamics in nonactivated and pre‐activated chromatin‐removed oocytes following transfer of nuclei from bovine fibroblast cells. Immediately after fusion between membranes of oocytes and fibroblasts, a microtubule aster containing a γ‐tubulin spot was seen near the transferred nucleus in most oocytes regardless of activation conditions. Most fibroblast nuclei transferred into nonactivated oocytes underwent premature chromosome condensation (PCC) and divided into two masses of chromosomes. In contrast, fibroblast nuclei in pre‐activated oocytes rarely underwent PCC, but formed a swelled pronuclear‐like structure. Under nonactivation condition, microtubular spindles surrounded condensed chromosomes during the division of two nuclear structures. Gamma‐tubulins were detected in the vicinity of condensed chromosomes, suggesting transient spindle formation. Two pronuclear‐like structures near the microtubular aster containing γ‐tubulin spot(s) later formed a syngamy‐like nuclear structure. While 20% of reconstructed oocytes under nonactivated conditions developed to morulae and blastocysts, only 4% of reconstructed oocytes under pre‐activated conditions developed to morulae and blastocysts. These results suggest introduction of a foreign centrosome during somatic cell nuclear transfer, which probably plays a role in nuclear remodeling and subsequent development. Mol. Reprod. Dev. 62: 74‐82, 2002. © 2002 Wiley‐Liss, Inc.
Evolution of octopod sperm II: Comparison of acrosomal morphogenesis in Eledone and Octopus
Authors: Ribes Enric , Gimenez‐Bonafé Pepita , Zamora Maria J. , Gonzalez Angel , Kasinsky Harold , Chiva Manel 
Published: August 2002

AbstractThe first stages of acrosome development during Eledone cirrhosa spermiogenesis are similar to that in Octopus vulgaris, and comprise the initial elongation of both organelles. However, the acrosome in E. cirrhosa does not continue its elongation as it does in O. vulgaris. Instead, its length remains fixed and it undergoes a process of helicoidization that includes the entire organelle. In each spermatid, helicoidization of the E. cirrhosa acrosome occurs simultaneously with helicoidization of the nucleus. The acrosome is associated with special structures that probably are involved in the helical torsion of the organelle. We propose a hypothesis to explain the evolutionary relationship between the acrosomes of O. vulgaris and E. cirrhosa, particularly as it is influenced by nucleomorphogenesis and microtubular contraction. Mol. Reprod. Dev. 62: 363–367, 2002. © 2002 Wiley‐Liss, Inc.
Sperm nuclear halos can transform into normal chromosomes after injection into oocytes
Authors: Mohar Isaac , Szczygiel Monika A. , Yanagimachi Ryuzo , Ward W. Steven 
Published: August 2002

AbstractMouse sperm nuclei extracted with an ionic detergent and 2 M NaCl retain their overall morphology, but upon subsequent reduction of the protamine disulfides they lose all elements of chromatin structure except the organization of DNA into loop that are anchored to the nuclear matrix. These DNA loops appear as a halo surrounding the nuclear matrix, and nuclei extracted in this manner are, therefore, called nuclear halos. Here, we report that sperm nuclear halos injected into oocytes can form pronuclei, then transform into chromosomes with normal morphology. This suggests that sperm nuclear halos retain all the information necessary for normal chromosomal organization, and that micromanipulation of these extracted sperm nuclei can be accomplished without major DNA damage. Mol. Reprod. Dev. 62: 416–420, 2002. © 2002 Wiley‐Liss, Inc.
In vivo analysis of the regulation of the anti‐Müllerian hormone, as a marker of Sertoli cell differentiation during testicular development, reveals a multi‐step process
Authors: Beau Charlotte , Vivian Nigel , Münsterberg Andrea , Dresser David W. , Lovell‐Badge Robin , Guerrier Daniel 
Published: August 2002

AbstractAnti‐Müllerian hormone (AMH) is a member of the TGF‐β family which elicits its main action during male sex differentiation. This hormone is probably the most convenient marker of Sertoli cell differentiation and maturation throughout testicular development. Studying AMH gene regulation may thus be one way of identifying effectors of Sertoli cell differentiation. To this end we first tried to locate and then to characterise DNA elements responsible for in vivo transcriptional control of AMH expression. We obtained transgenic mice expressing a reporter gene (LacZ), under control of various putative AMH regulatory sequences. Analysis of transgenic animals revealed that activation of the AMH gene probably requires a two‐step regulatory process. The first step corresponds to the initial activation of the AMH gene occurring at around 12.0‐dpc. It requires the presence of regulatory DNA encompassed within a maximum of 370‐bp upstream of the translation start site of the gene, delimited by the presence of an upstream housekeeping gene (SAP‐62). Following this initial transient phase, a second phase seems to account for the persistence of AMH gene expression until the onset of puberty. As the 370‐bp regulatory region is not sufficient on its own to allow the triggering of this second phase, it seems possible that additional control elements are required for normal AMH expression throughout testicular development. The complete array of regulatory elements remains to be located. Mol. Reprod. Dev. 59:256–264, 2001. © 2001 Wiley‐Liss, Inc.
Estrogen receptor‐ and aromatase‐deficient mice provide insight into the roles of estrogen within the ovary and uterus*
Authors: Rosenfeld Cheryl S. , Roberts R. Michael , Lubahn Dennis B. 
Published: August 2002

AbstractEstrogen receptor (ER)‐ (α, β, and both α and β) and aromatase (Ar) knockout (KO) mice have been created to assess the biological effects of estrogens. This review article discusses the ovarian and uterine phenotypes of these mice. The data obtained have confirmed some older inferences about how the steroid acts, but have also revealed some unexpected aspects of estrogen action. Mol. Reprod. Dev. 59:336–346, 2001. © 2001 Wiley‐Liss, Inc.
Storage in the yolk platelets of low MW DNA produced by the regressing follicle cells
Authors: Motta C.M. , Tammaro S. , Cicale A. , Indolfi P. , Iodice C. , Spagnuolo M.S. , Filosa S. 
Published: August 2002

AbstractThe present work was carried out to clarify the nature and origin of the yolk DNA present in vitellogenic oocytes of the lizard Podarcis sicula. Morphological and biochemical evidences indicate that it has an intrafollicular origin, from the apoptotic bodies resulting from follicle cells regression at the end of previtellogenesis. This conclusion is reinforced by the observation that the oocyte membrane, in in vitro experiments, is unpermeable to exogenous DNA. Biochemical evidences reveal that the yolk DNA has a low (200bp) molecular weight and this suggests that it is produced by the endonucleases typically involved in apoptotic DNA laddering. Indeed, immunocytochemical analyses demonstrate that follicle cells contain significant amounts of DNAse I. In immunoblots, carried out during different periods of the ovarian cycle, the enzyme shows a MW of about 33, 66 or 100 kDa thus indicating that its activity in the follicle of Podarcis is modulated by dimerization and/or binding to regulatory factors. Mol. Reprod. Dev. 59: 422–430, 2001. © 2001 Wiley‐Liss, Inc.
Distribution of lectin‐binding glycosidic residues in the hamster follicular oocytes and their modifications in the zona pellucida after ovulation
Authors: El‐Mestrah Majid , W. K. Kan Frederick 
Published: August 2002

AbstractIn the present study, we have employed a battery of colloidal gold‐tagged lectins as probes in conjunction with quantitative analysis to demonstrate the distribution and changes of carbohydrate residues in the hamster zona pellucida (ZP) during ovarian follicular development and during transit of the oocyte through the oviduct after ovulation. High‐resolution lectin–gold cytochemistry performed on thin sections of LR White‐embedded ovaries revealed a moderate to strong reactivity to WGA, PNA, DSA, AAA, and MAA over the entire thickness of the ZP of ovarian oocytes at different stages of follicular development. Labeling intensity over the ZP progressively increased as follicles matured in the ovary. In parallel, there was an association of labeling by gold particles with cortical granules, stacks of Golgi saccules, and complex structures called vesicular aggregates in the oocyte proper especially during the late stages of follicular growth. In contrary, labeling with each of HPA, DBA, and BSAIB4 was absent in the ovary but was found to be localized over Golgi complexes and secretory granules in the non‐ciliated secretory cells of the oviduct. When ovulated oocytes were labeled with each of HPA, WGA, RCA‐I, PNA, DSA, BSAIB4, AAA, MAA, and DBA, the ZP and several organelles in the oocyte proper presented a differential distribution of lectin‐binding sites. Quantitative analysis was also performed on labeling by lectin–gold complexes that bind specifically to the ZP of mature follicular and ovulated oocytes. Quantitative evaluation revealed heterogeneous labeling between the inner and the outer zone of the ZP. A significant increase in the labeling densities in both inner and outer ZP was noted when tissue sections of ovulated oocytes were labeled with RCA‐I or AAA. Tissue sections of ovaries labeled with WGA demonstrated a significant increase in the density of labeling in the outer layer of the ZP. Labeling by PNA, DSA, and MAA, however, showed a significant decrease in both the inner and outer portions of the ZP. Together, these results suggest that in the hamster, glycoproteins carrying specific sugar residues are added to the ZP of ovarian follicles during the early stages of folliculogenesis and are processed through a common secretory machinery, and that there is a significant change in both the sugar moieties and distribution of glycoproteins in the ZP following ovulation. Our results also showed that the hamster oviduct plays an important role in contributing certain glycoproteins to the ZP suggesting that the sugar moieties of these oviductal glycoproteins may have functional significance in fertilization. Mol. Reprod. Dev. 60: 517–534, 2001. © 2001 Wiley‐Liss, Inc.
Magnetic resonance microscopy of morphological alterations in mouse trabecular bone structure under conditions of simulated microgravity
Authors: Gardner John R. , Hess Christopher P. , Webb Andrew G. , Tsika Richard W. , Dawson M. Joan , Gulani Vikas 
Published: August 2002

AbstractThis work describes the use of magnetic resonance (MR) microscopy to examine changes in tibial trabecular bone structure in mice following 28 days of hindlimb suspension, a model simulating the effects of microgravity in rodents. In this first MR study involving mice, analysis of 3D images showed that apparent bone volume fraction, trabecular number, and trabecular thickness were decreased, and apparent trabecular spacing increased, significantly (P < 0.05) in hindlimb‐suspended mice compared to controls. These changes agreed well with light microcopy measurements from an independent study and also with actual spaceflight experiments with rats. Magn Reson Med 45:1122–1125, 2001. © 2001 Wiley‐Liss, Inc.
Slab scan diffusion imaging
Authors: Maier Stephan E. 
Published: August 2002

AbstractFor maximum robustness of a diffusion‐weighted MR imaging sequence, it is desirable to use a single‐shot imaging method. This article introduces a new single‐shot imaging approach that combines the advantages of multiple spin‐echoes with the technique of line scan diffusion imaging. A slab volume, which can be spatially encoded with fewer phase encodes than a regular field of view, is selected with 2D selective pulses. With the shorter echo train, the sensitivity to field inhomogeneities and chemical shift is thus greatly diminished. Further reduction is achieved by interleaving short gradient echo trains with refocusing spin‐echo pulses. Optimized slice‐selective RF pulses that produce flip angles close to 180° are used to minimize the stimulated echo component. Motion‐related phase shifts, which change polarity with each spin‐echo excitation, will give rise to artifacts that are avoidable by processing even and odd spin‐echoes separately. As with line scan diffusion imaging, the complete field of view is acquired by sequential scanning. Since with each shot several lines of data are collected, a considerable improvement over line scan diffusion imaging in terms of scanning speed is achieved. Diffusion data obtained in phantoms and normal subjects demonstrate the feasibility of this novel approach. Magn Reson Med 46:1136–1143, 2001. © 2001 Wiley‐Liss, Inc.
Mechanisms underlying human motor system plasticity
Authors: Boroojerdi Babak , Ziemann Ulf , Chen Robert , Bütefisch Cathrin M. , Cohen Leonardo G. 
Published: August 2002

AbstractThere has been increased interest in the ability of the adult human nervous system to reorganize and adapt to environmental changes throughout life. This ability has been termed “plasticity.” Plastic changes in the cerebral cortex have been studied: (a) as modifications of sensory or motor cortical representation of specific body parts (cortical maps, body representation level); and (b) as changes in the efficacy of existing synapses or generation of new synapses (neuronal or synaptic level). In this review, we describe paradigms used to study mechanisms of plasticity in the intact human motor system, the functional relevance of such plasticity, and possible ways to modulate it. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 602–613, 2001
The anesthetic propofol modulates gating in paramyotonia congenita mutant muscle sodium channels
Authors: Haeseler Gertrud , Störmer Martina , Mohammadi Bahram , Bufler Johannes , Dengler Reinhard , Piepenbrock Siegfried , Leuwer Martin 
Published: August 2002

AbstractWe examined the effects of propofol on a paramyotonia congenita mutant skeletal muscle sodium channel in vitro, because life‐threatening complications resulting from severe muscle rigidity during induction of anesthesia have been observed using other anesthetics in patients with hereditary sodium channel myopathies. Our hypothesis was that propofol might interact directly with mutant channels, causing enhanced muscle excitability in affected patients. Whole‐cell voltage‐clamp experiments were performed on HEK 293 cells expressing R1448H mutant sodium channels. Propofol blocked sodium inward current at clinical concentrations (5 μmol/L) when depolarizing pulses were started from holding potentials close to the physiological resting potential (−70 mV). Higher propofol concentrations (≥25 μmol/L) accelerated pathologically delayed inactivation kinetics and delayed pathologically enhanced recovery from inactivation. Our in vitro results show that inactivation‐deficient sodium channels are specifically targeted and blocked by propofol. This might reduce enhanced muscle excitability experienced by affected patients in vivo. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 736–743, 2001
Kell and XK immunohistochemistry in McLeod myopathy
Authors: Jung Hans H. , Russo David , Redman Colvin , Brandner Sebastian 
Published: August 2002

AbstractThe McLeod syndrome is an X‐linked neuroacanthocytosis manifesting with myopathy and progressive chorea. It is caused by mutations of the XK gene encoding the XK protein, a putative membrane transport protein of yet unknown function. In erythroid tissues, XK forms a functional complex with the Kell glycoprotein. Here, we present an immunohistochemical study in skeletal muscle of normal controls and a McLeod patient with a XK gene point mutation (C977T) using affinity‐purified antibodies against XK and Kell proteins. Histological examination of the affected muscle revealed the typical pattern of McLeod myopathy including type 2 fiber atrophy. In control muscles, Kell immunohistochemistry stained sarcoplasmic membranes. XK immunohistochemistry resulted in a type 2 fiber‐specific intracellular staining that was most probably confined to the sarcoplasmic reticulum. In contrast, there was only a weak background signal without a specific staining pattern for XK and Kell in the McLeod muscle. Our results demonstrate that the lack of physiological XK expression correlates to the type 2 fiber atrophy in McLeod myopathy, and suggest that the XK protein represents a crucial factor for the maintenance of normal muscle structure and function. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1346–1351, 2001
Simplified orthodromic inching test in mild carpal tunnel syndrome
Authors: Seror Paul 
Published: August 2002

AbstractThis prospective study was undertaken to determine the clinical relevance, reliability, sensitivity, and specificity of the orthodromic inching test with 2‐cm incremental study of the median nerve over the four intracarpal centimeters in 50 control and 50 successive (unselected) patient wrists with mild carpal tunnel syndrome (CTS). In controls, the mean maximum conduction delay per 2 cm (CD/2cm) was 0.445 ± 0.04 ms, and abnormality was defined as at least one CD/2cm exceeding the mean + 2.5 SD of the normal CD/2cm. This yielded a specificity of 98%. In patients with mild unselected CTS, this simplified orthodromic inching test (SOIT) detected the median nerve lesion at the wrist in 47 cases (sensitivity = 94%). The SOIT detected 15 more CTS cases than did the orthodromic median‐ulnar latency difference of the 4th digit (Chi square = 13; P = .002). Thus, the SOIT was as effective as an incremental study every centimeter over 10 cm, and the time required for the test allows its routine use when other electrodiagnostic tests fail to reveal any median nerve impairment. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1595–1600, 2001
Effect of degenerate spherical harmonics and a method for automatic shimming of oblique slices
Authors: Shen Jun 
Published: August 2002

AbstractSeveral spherical harmonics degenerate on an oblique plane. Two‐dimensional field mapping of an oblique slice causes ambiguity in determination of the degenerate spherical harmonics terms. Therefore, automatic shimming of oblique slices may lead to erroneous adjustment of shims corresponding to the degenerate spherical harmonics. In this paper an automatic slice shimming technique derived from the FASTMAP method (Gruetter R. Magn. Reson. Med. 1993; 29, 804–811) is proposed. This new method unequivocally determines and corrects all of the first‐ and the second‐order shims for slices of arbitrary orientation. Copyright © 2001 John Wiley & Sons, Ltd.
Abbreviations used:

FOV

field of view

ROI

region of interest

S/N

signal‐to‐noise ratio.
Contraction increases the T2 of muscle in fresh water but not in marine invertebrates
Authors: Meyer Ronald A. , Prior Barry M. , Siles Roxana I. , Wiseman Robert W. 
Published: August 2002

AbstractPrevious studies suggest that the activity‐induced increase in 1H‐NMR transverse relaxation time (T2) observed in mammalian skeletal muscles is related to an osmotic effect of intracellular metabolite accumulation. This hypothesis was tested by comparing T2 (measured by 1H‐NMR imaging at 4.7 T) and metabolite changes (measured by 31P‐NMR spectroscopy) after stimulation in the muscles of a freshwater (crayfish, Orconectes virilis) vs two osmoconforming marine invertebrates (lobster, Homarus americanus; scallop, Argopecten concentricus). Intracellular pH significantly decreased after stimulation in the lobster tail muscle, but not in the crayfish tail or scallop phasic adductor muscles. The decrease in phosphoarginine‐to‐ATP ratio after stimulation was similar in the three muscles. Muscle T2 increased from 37 to 43 ms (p < 0.02, n = 7) after stimulation in crayfish, but was unchanged in lobster muscle (32 ms, n = 7), and significantly decreased (from 40 to 36 ms, p < 0.02, n = 11) in scallop muscle. The observation that T2 does not increase after stimulation in muscles of marine invertebrates with high natural osmolarity is consistent with the hypothesis that the T2 increase in mammalian muscle is related to osmotically driven shifts of fluid between subcellular compartments. Copyright © 2001 John Wiley & Sons, Ltd.
Abbreviations used:

PArg

phosphoarginine

Pi

inorganic phosphate
Homogeneous sets and domination: A linear time algorithm for distance—hereditary graphs
Authors: Nicolai Falk , Szymczak Thomas 
Published: August 2002

AbstractIn this paper, we consider the r‐dominating set problem on graphs which can be generated from the one‐vertex graph by a finite number of homogeneous extensions and by attaching pendant vertices. We show that for such graphs a minimum cardinality r‐dominating set can be computed in O(|V| |E|) time; for distance—hereditary graphs—a proper subclass—we even get a linear time algorithm. Furthermore, since these graph classes are closed under adding false twins, a total dominating set can be computed in the same time bound. © 2001 John Wiley & Sons, Inc.
Maximizing residual flow under an arc destruction
Authors: Aneja Y. P. , Chandrasekaran R. , Nair K. P. K. 
Published: August 2002

AbstractIn this paper, we consider two problems related to single‐commodity flows on a directed network. In the first problem, for a given s – t flow, if an arc is destroyed, all the flow that is passing through that arc is destroyed. What is left flowing from s to t is the residual flow. The objective is to determine a flow pattern such that the residual flow is maximized. We provide a strongly polynomial algorithm for this problem, called the maximum residual flow problem, and consider various extensions of this basic model. In the second problem, known as the “most vital arc” problem, the objective is to remove an arc so that the maximal flow on the residual network is as small as possible. Results are also derived which help implement an efficient scheme for solving this problem. © 2001 John Wiley & Sons, Inc.
Exact algorithms for minimum routing cost trees
Authors: Fischetti Matteo , Lancia Giuseppe , Serafini Paolo 
Published: August 2002

AbstractGiven a set of points and distances between them, a basic problem in network design calls for selecting a graph connecting them at a minimum total routing cost, that is, the sum over all pairs of points of the length of their shortest path in the graph. In this paper, we describe some branch‐and‐bound algorithms for the exact solution of a relevant special case arising when the graph has to be a tree. One of the enhancements to our algorithms is the use of “LP shortcutting,” which we introduce as a general‐purpose technique for speeding up the search. Besides network design, we show how trees of small routing cost find useful application in computational biology, where they can be used to determine good alignments of genomic sequences. This leads to a novel alignment heuristic that we analyze in our computational section. © 2002 Wiley Periodicals, Inc.