bluuebunny/crossref_metadata_2025_split huggingface dataset:
Doppler sonography of normal fetal vertebral and internal carotid arteries during pregnancy
Authors: Morales‐Roselló José 
Published: August 2002

AbstractPurposeThe aim of this study was to determine the resistance index (RI) in the fetus in both the vertebral artery and the internal carotid artery and to evaluate the relationship of those RIs with that of the umbilical artery.MethodsIn this prospective study, color Doppler examinations of the vertebral, internal carotid, and umbilical arteries were performed in fetuses with normal growth between 17 and 41 weeks' gestational age. For every week, the 10th, 50th, and 90th percentiles of the RIs in the 3 arteries plus the ratios of the RIs of the vertebral and umbilical arteries and of the internal carotid and umbilical arteries were calculated.ResultsIn 225 examinations in 114 women, the vertebral and internal carotid arteries showed similar RI patterns, with higher RIs at mid gestation. The only difference was that the RIs in the internal carotid artery reached maximum values at a slightly later gestational age (26–28 weeks) than did those in the vertebral artery (24–25 weeks). Also, the RIs in the vertebral artery were slightly higher than were those in the internal carotid artery. RI values in the umbilical artery decreased progressively throughout gestation. Conversely, the ratios of the RIs in the vertebral and umbilical arteries and those of the RIs in the internal carotid and umbilical arteries increased slightly until the end of pregnancy, with the former ratios always higher than the latter ones.ConclusionsIn normal fetuses, the pattern of blood flow resistance in the vertebral artery resembles that in the internal carotid artery. However, compared with the internal carotid artery, the vertebral artery shows higher absolute RIs with maximum values appearing earlier in the course of pregnancy. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:257–263, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.10069
Early development in males with Fragile X syndrome: A review of the literature
Authors: Kau Alice S.M. , Meyer Walter A. , Kaufmann Walter E. 
Published: August 2002

AbstractThis article reviews the current bibliographic knowledge on early neurobehavioral development and milestones in Fragile X syndrome (FraX), with emphasis on males affected by the condition. Three broad areas of early development were examined: (1) gross and fine motor, (2) speech and language, and (3) social. The result of the current review indicates very limited information on the developmental milestones in all three areas. The scarce literature on motor development shows that in FraX there is an early developmental delay. Research on speech and language demonstrates pervasive deficits in conversational skills and severe developmental delay, with increasing discrepancy between language level and chronological age in young males with FraX. Finally, deficits in social development in FraX include abnormal gaze, approach and avoidance conflict, and high incidence of autistic spectrum disorders. Microsc. Res. Tech. 57:174–178, 2002. © 2002 Wiley‐Liss, Inc.
Podocyte is the major culprit accounting for the progression of chronic renal disease
Authors: Kriz Wilhelm 
Published: August 2002

AbstractThe concept that the podocyte is the major culprit underlying development and progression of glomerular diseases leading to chronic renal failure is well established. The essential steps in this process are (1) the establishment of tuft adhesions to Bowman's capsule; (2) the formation by capillaries contained in a tuft adhesion of a filtrate that is delivered, instead into Bowman's space, towards the interstitium; and (3) the spreading of this filtrate on the outer aspect of the affected nephron leading to the degeneration of this nephron. The present review summarizes the pros and cons concerning the relevance of misdirected filtration for a nephron‐to‐nephron transfer of the disease at the level of the tubular interstitium. Surprisingly, the histopathology clearly shows that interstitial proliferation surrounding degenerating nephrons tends to encapsulate the degenerative process, confining it to the already affected nephron. No evidence is available that the disease, mediated by interstitial proliferation and matrix deposition, may jump to a neighboring, so far unaffected, nephron. It appears that the process that leads to the degeneration of a nephron in the context of “classic” FSGS always starts separately in the respective glomerulus by severe podocyte injury. Microsc. Res. Tech. 57:189–195, 2002. © 2002 Wiley‐Liss, Inc.
Podocyte process effacement in vivo
Authors: Shirato Isao 
Published: August 2002

AbstractFoot process effacement is the most characteristic change in podocyte structure under a wide variety of human and experimental glomerulopathies with heavy proteinuria. It consists of simplification and even total disappearance of the interdigitating foot process pattern, resulting in the formation of a diffuse cytoplasmic sheet along the glomerular basement membrane. Although abundant evidence related to structural changes in podocyte foot processes has been reported, cellular or molecular mechanisms that occur within podocytes during the development of foot process effacement remain unclear. This review summarizes recent advances concerning structural and functional aspects of foot process effacement in vivo. Following a description of the general morphology of foot process effacement, the role of the cytoskeleton and its related proteins in the effacement are discussed. Finally, the relevance of foot process effacement in glomerular function is considered. Microsc. Res. Tech. 57:241–246, 2002. © 2002 Wiley‐Liss, Inc.
Neuroimaging in headache
Authors: Goadsby Peter J. 
Published: August 2002

AbstractNeuroimaging of primary headache syndromes, such as cluster headache and migraine, has begun to provide a glimpse of the neuroanatomical and physiological basis of the conditions. Although these headache types have been widely described as vascular, there is now considerable imaging and clinical evidence to suggest that they are primarily driven from the brain. The shared anatomical and physiological substrate for both of these clinical problems is the neural innervation of the cranial circulation. Functional imaging with positron emission tomography (PET) has shed light on the genesis of both syndromes, documenting activation in the midbrain and pons in migraine, and in the hypothalamic grey in cluster headache. These areas are involved not simply as a response to first division nociceptive pain impulses but specifically in each syndrome, probably in some permissive or dysfunctional role. In a recent PET study in cluster headache, as well as brain activation, tracer pooled in the region of the major basal arteries. This is likely to be due to vasodilatation of these vessels during the acute pain‐attack and represents the first convincing activation of neural vasodilator mechanisms in humans. The author takes the view that the known physiology and pathophysiology of the systems involved dictate that these disorders should be collectively regarded as neurovascular headaches to place emphasis on the interaction between nerves and vessels, which is the underlying characteristic of these syndromes. Understanding this neurovascular relationship facilitates an understanding of the pain mechanisms, while characterising the CNS dysfunction will ultimately allow us to dissect out the basic pathogenesis of these disorders. Microsc. Res. Tech. 53:179–187, 2001. © 2001 Wiley‐Liss, Inc.
Cadmium distribution and toxicity in tissues of small rodents
Authors: Świergosz‐Kowalewska Renata 
Published: August 2002

AbstractThe aim of the present paper is to discuss the accumulation and distribution of cadmium (Cd) in the various tissues of animals, the interactions of cadmium with other elements, and the damage to tissues caused by this metal. Cadmium is not physiologically or biochemically essential to an organism. It is absorbed via the gastrointestinal tract and lungs and accumulated in various tissues, mainly the kidneys and liver. The distribution of cadmium between various tissues depends on many endogenous and exogenous factors. Cadmium is bound to a low‐molecular‐weight protein, metallothionein (MT), and to high‐molecular‐weight proteins. This metal has a great affinity to thiol groups. Cadmium binds also to O‐ and N‐containing ligands. The distribution of cadmium between organs differs markedly depending on the chemical form of administered Cd and the duration of exposure. Acute exposure results in a different distribution pattern throughout the body than does chronic exposure. Long‐term exposure to high doses of cadmium may cause biochemical and functional changes in some critical organs. Cadmium can influence the absorption and distribution of essential elements and can replace them in enzymes. Metallothionein and glutathione play important roles in the transport of metals and in detoxification processes. Reported findings are mainly the results of experiments on laboratory animals. The lack of data concerning the localization of cadmium in various tissues of wild species is noticeable and there is a great need for such data. Microsc. Res. Tech. 55:208–222, 2001. © 2001 Wiley‐Liss, Inc.
Antennal sensilla of the ground beetle Platynus dorsalis (Pontoppidan, 1763) (Coleoptera, carabidae)
Authors: Merivee Enno , Ploomi Angela , Luik Anne , Rahi Märt , Sammelselg Väino 
Published: August 2002

AbstractThe typology, number, and distribution pattern of antennal sensilla of the ground beetle Platynus dorsalis (Pontoppidan) (Coleoptera, Carabidae) were studied using scanning electron microscopy. The 4.3–4.6‐mm‐long filiform antennae of the beetles consist of the scape, pedicel, and nine flagellomeres. In both sexes, four subtypes of sensilla chaetica, five subtypes of sensilla basiconica, sensilla trichodea, two subtypes of sensilla campaniformia, sensilla auricillica, and sensilla coeloconica were distinguished. The possible function of the sensilla was discussed and three types of sensilla were considered as olfactory, sensilla trichodea and sensilla basiconica types 1 and 2. Olfactory sensilla form two separate, dorsal and ventral, fields of sensilla on the flagellomeres, which seems to be common in ground beetles. The total numbers of olfactory trichoid (approximately 1,000 hairs) and basiconic sensilla type 1 (1,700–1,800 pegs) on the antennae of P. dorsalis are 5–7 times higher than on the antennae of the ground beetle Bembidion lampros, suggesting that nocturnally active P. dorsalis is much more sensitive to odours perceived by these sensilla than B. lampros with diurnal activity and hunting predominantly by sight. No remarkable sexual differences in the types, numbers, and distribution of antennal sensilla were found in P. dorsalis. Microsc. Res. Tech. 55:339–349, 2001. © 2001 Wiley‐Liss, Inc.
Basic properties and annual changes of follicle‐stimulating hormone receptors in the testis of horseshoe bats, Rhinolophus ferrumequinum
Authors: Hayashi Toshiyuki , Uchida Katsuya , Kawamoto Keiichi 
Published: August 2002

AbstractThe unique reproductive patterns, delayed fertilization in females, and asynchrony between spermatogenesis and mating behavior in males are well documented in bats living in temperate latitudes. The present study was undertaken to examine follicle‐stimulating hormone (FSH) receptors in the testis of bats, Rhinolophus ferrumequinum, during the annual reproductive cycle. Male bats were captured at natural roosting sites and testicular preparations were subjected to a radioligand binding assay for FSH receptors. The weight of paired testes increased considerably in the spermatogenic period and decreased from the mating to hibernation periods. Meiotic division in the testis was observed in the spermatogenic period but not the mating period. Serum testosterone concentrations increased in the spermatogenic period and rapidly decreased in the mating period. The binding of FSH was specific for mammalian FSHs and detected primarily in the testis. Scatchard plot analyses of the binding of FSH to bat testicular preparations showed straight lines, suggesting the presence of a single class of binding sites. The affinities (equilibrium association constant) of FSH receptors were consistent throughout the annual reproductive cycle. The specific binding per unit weight of testis and total binding in the paired testes were highest in the mating period and in the spermatogenic period, respectively, among reproductive periods. The accumulation of cyclic adenosine 3′, 5′‐monophosphate to FSH stimulation was higher in the spermatogenic period than in the hibernation period. These findings suggest that testicular function of bats is associated with seasonal changes in the number of binding sites, while the number per target cell and the activation of adenylate cyclase led by FSH‐receptor complex considerably decreases in the hibernation period. J. Exp. Zool. 292:304–313, 2002. © 2002 Wiley‐Liss, Inc.
Segment‐specific expression of alkaline phosphatase in the Tubifex embryo requires DNA replication and mRNA synthesis
Authors: Kitamura Kaoru , Shimizu Takashi 
Published: August 2002

AbstractDuring embryogenesis of the oligochaete annelid Tubifex, segments VII and VIII specifically express mesodermal alkaline phosphatase (ALP) activity in the ventrolateral region. In this study, using specific inhibitors, we examined whether this segment‐specific expression of ALP activity depends on DNA replication and RNA transcription. BrdU‐incorporation experiments showed that presumptive ALP‐expressing cells undergo the last round of DNA replication at 12–24 hr prior to emergence of ALP activity. When this DNA replication was inhibited by aphidicolin, ALP development was completely abrogated in the ventrolateral mesoderm. Similar inhibition of ALP development was also observed in α‐amanitin‐injected embryos. While injection of α‐amanitin at 24 hr prior to the emergence of ALP activity exerted inhibitory effects on ALP development, injection at 14 hr was no longer effective. In contrast, ALP activity developed normally in cytochalasin‐D‐treated embryos in which cytokinesis was prevented from occurring for 36 hs prior to appearance of ALP activity. These results suggest that the segment‐specific development of ALP activity in the Tubifex embryo depends on DNA replication and mRNA transcription, both of which occur long before the emergence of ALP activity. J. Exp. Zool. (Mol. Dev. Evol.) 294:68–76, 2002. © 2002 Wiley‐Liss, Inc.
Retinoid antagonists inhibit normal patterning during limb regeneration in the axolotl, Ambystoma mexicanum
Authors: Del Rincón Sonia V. , Scadding Steven R. 
Published: August 2002

AbstractRetinoic acid (RA) has been detected in the regenerating limb of the axolotl, and exogenous RA can proximalize, posteriorize, and ventralize blastemal cells. Thus, RA may be an endogenous regulatory factor during limb regeneration. We have investigated whether endogenous retinoids are essential for patterning during axolotl (Ambystoma mexicanum) limb regeneration by using retinoid antagonists that bind to specific RAR (retinoic acid receptor) or RXR (retinoid X receptor) retinoid receptor subtypes. Retinoid antagonists (Ro41‐5253, Ro61‐8431, LE135, and LE540) were administered to regenerating limbs using implanted silastin blocks loaded with each antagonist. The skeletal pattern of regenerated limbs treated with Ro41‐5253 or Ro61‐8431 differed only slightly from control limbs. Treatment with LE135 inhibited limb regeneration, while treatment with LE540 allowed relatively normal limb regeneration. When LE135 and LE540 were implanted together, regeneration was not completely inhibited and a hand‐like process regenerated. These results demonstrate that interfering with retinoid receptors can modify pattern in the regenerating limb indicating that endogenous retinoids are important during patterning of the regenerating limb. J. Exp. Zool. 292:435–443, 2002. © 2002 Wiley‐Liss, Inc.
Molecular phylogenetic perspective on evolution of lizards of the Anolis grahami series
Authors: Jackman Todd R. , Irschick Duncan J. , De Queiroz Kevin , Losos Jonathan B. , Larson Allan 
Published: August 2002

AbstractWe report the results of phylogenetic analyses of 1447 bases of mitochondrial DNA sequence for 21 populations representing seven species of the Anolis grahami series (A. conspersus, A. garmani, A. grahami, A. lineatopus, A. opalinus, A. reconditus, and A. valencienni), six of which occur on Jamaica. These data include 705 characters that are phylogenetically informative according to parsimony. A parsimony analysis of these data combined with previously published allozymic data yields a single most parsimonious tree with strong support for monophyly of the A. grahami series, the sister‐group relationship between Anolis lineatopus and A. reconditus and a clade composed of Anolis garmani, A. grahami, and A. opalinus. Based on DNA data alone, A. conspersus is nested within A. grahami. Haplotypes sampled from geographic populations of A. grahami, A. lineatopus, and A. opalinus are highly divergent (≈12–15% sequence difference on average for each species) and show similar phylogeographic patterns, suggesting that each of these currently recognized species may be a complex of species. Anolis valencienni also shows high sequence divergence among haplotypes from different geographic populations (≈8% sequence difference) and may contain cryptic species. Divergence among haplotypes within A. garmani is substantially lower (≈3% sequence difference), and phylogeographic patterns are significantly different from those observed in A. grahami, A. lineatopus and A. opalinus. J. Exp. Zool. (Mol. Dev. Evol.) 294:1–16, 2002. © 2002 Wiley‐Liss, Inc.
Histidine uptake in the epidermis of lizards and snakes in relation to the formation of the shedding complex
Authors: Alibardi Lorenzo 
Published: August 2002

AbstractMammalian epidermis utilizes histidine‐rich proteins (filaggrins) to aggregate keratin filaments and form the stratum corneum. Little is known about the involvement of histidine‐rich proteins during reptilian keratinization. The formation of the shedding complex in the epidermis of snakes and lizards, made of the clear and the oberhautchen layers, determines the cyclical epidermal sloughing. Differently from snakes, keratohyalin‐like granules are present in the clear layer of lizards. The uptake of tritiated histidine into the epidermis of two lizards and one snake has been studied by autoradiography in sections at progressive post‐injection periods. At 40 min and 1 hr post‐injection keratohyalin‐like granules were not or poorly labeled. At 3–22 hr post‐injection most of the labeling was present over suprabasal cells destined to form the shedding complex, in keratohyalin‐like granules of the clear layer, and in the forming a‐layer but was low in the forming b‐layer, and in superficial keratinized layers. The analysis of the shedding complex in the pad lamellae (a specialized scale used for climbing) of a gecko showed that the setae and the cytoplasm of clear cells among them are main sites of histidine uptake at 4 hr post‐injection. In the snake most of the labeling at 4 hr post‐injection was localized in the shedding complex along the boundary between the clear and oberhautchen layers. The present study suggests that, in the epidermis of lepidosaurian reptiles, the synthesis of a histidine‐rich protein is involved in the formation of the shedding layer and, as in mammals, in a‐keratinization. J. Exp. Zool. 292:331–344, 2002. © 2002 Wiley‐Liss, Inc.
Cyclopamine induces digit loss in regenerating axolotl limbs
Authors: Roy Stéphane , Gardiner David M. 
Published: August 2002

AbstractAxolotls, with their extensive ability to regenerate as adults, provide a useful model for studying the mechanisms of regeneration in a vertebrate, in hopes of understanding why other vertebrates cannot regenerate. Although the expression of many genes has been described in regeneration, techniques for gain and loss of function analyses have been limited. We demonstrated in a previous study that gain of function for secreted proteins was possible in the axolotl using the vaccinia virus to drive expression of the transgene. In this study, we used a pharmacological approach made possible by the existence of a naturally occurring compound that specifically blocks shh signaling, cyclopamine. The treatment of axolotls with cyclopamine during the process of limb regeneration caused a loss of digits similar to that described for the shh knockout mouse. Our results further demonstrate that shh signaling and function are conserved during limb regeneration in urodeles as in limb development in other vertebrates. © 2002 Wiley‐Liss, Inc.
Identification of α1‐adrenergic receptors and their involvement in phosphoinositide hydrolysis in the frog heart
Authors: Lazou Antigone , Gaitanaki Catherine , Vaxevanellis Spiros , Pehtelidou Anastasia 
Published: August 2002

AbstractThe aim of this study was to characterize α1‐adrenergic receptors in frog heart and to examine their related signal transduction pathway. α1‐Adrenergic binding sites were studied in purified heart membranes using the specific α1‐adrenergic antagonist [3H]prazosin. Analysis of the binding data indicated one class of binding sites displaying a Kd of 4.19 ± 0.56 nM and a Bmax of 14.66 ± 1.61 fmol/mg original wet weight. Adrenaline, noradrenaline, or phenylephrine, in the presence of propranolol, competed with [3H]prazosin binding with a similar potency and a Ki value of about 10 μM. The kinetics of adrenaline binding was closely related to its biological effect. Adrenaline concentration dependently increased the production of inositol phosphates in the heart in the presence or absence of propranolol. Maximal stimulation was about 8.5‐fold, and the half‐maximum effective concentration was 30 and 21 μM in the absence and presence of propranolol, respectively. These data clearly show that α1‐adrenergic receptors are coupled to the phosphoinositide hydrolysis in frog heart. To our knowledge, this is the first direct evidence supporting the presence of functional α1‐adrenergic receptors in the frog heart. © 2002 Wiley‐Liss, Inc.