bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alligator aromatase cDNA sequence and its expression in embryos at male and female incubation temperatures
Authors: Gabriel Willow N. , Blumberg Bruce , Sutton Stacy , Place Allen R. , Lance Valentine A. 
Published: August 2002

AbstractIn all species of crocodilians, sex is determined not by genetic mechanisms, but by the temperature at which the egg is incubated. In the American alligator (Alligator mississippiensis) the thermosensitive period (TSP) for sex determination is a 7‐ to 10‐day window within stages 21–24 of development, around the middle third of the incubation period. Treating embryos with estrogen during the TSP produces female offspring, even at male incubation temperatures. Conversely, blocking embryonic estrogen synthesis at female‐inducing temperature prevents development of the female phenotype. Therefore, it has been suggested that estrogen plays a role in determination of sex in the alligator. Estrogen is produced from an androgen substrate by cytochrome P450 aromatase (CYP19). If estrogen plays a critical role in sex determination, there should be differences in aromatase expression between embryos at male‐ and female‐producing temperatures during the TSP. Therefore, to address this question, we cloned and characterized the alligator CYP19 cDNA. Based on the sequence information, a quantitative kinetic reverse transcriptase–polymerase chain reaction (TaqMan) assay was designed to measure expression of the alligator aromatase gene in RNA extracted from the gonadal and brain regions of alligator embryos incubated at male‐ or female‐producing temperatures from prior to the TSP through hatching. Aromatase expression was detected in the brain region from the earliest stage tested (stage 20) through hatching. The hypothalamus had significantly higher expression than the forebrain or hindbrain in both male and female embryos. Expression was not significantly different in the gonadal region between embryos at male and female temperatures until after the TSP, when there was a dramatic increase in expression at female temperature. These data indicate that aromatase expression and, thus, estrogen production, are not the initial trigger for sex determination but play an essential role in ovarian differentiation in the alligator. J. Exp. Zool. 290:439–448, 2001. © 2001 Wiley‐Liss, Inc.
Uterine epithelial‐sperm interaction, endometrial cycle and sperm storage in the terminal zone of the oviducal gland in the placental smoothhound,Mustelus canis
Authors: Hamlett William C. , Musick John A. , Hysell Christopher K. , Sever David M. 
Published: August 2002

AbstractThe fate of spermatozoa deposited within the female reproductive tract has been described in the smoothhound,Mustelus canis. Evidence of uterine epithelial‐sperm interaction is presented, as well as documentation of sperm storage specifically in the terminal zone of the oviducal gland. Sperm fate is correlated with morphology of the endometrial cycle and specificity of storage in the oviducal gland. The endometrium ofM. canisundergoes dramatic tissue remodeling associated with gestation. In females harboring fertilized ova or preimplantation yolk‐reliant embryos, the uterine epithelium is simple cuboidal with mucous droplets for lubrication. The presence of the embryo elicits a response from the uterus, which becomes modified for nutrient and respiratory exchange into vascular uterine attachment sites that abut the distal aspect of the yolk sac. Areas of the uterus adjacent to the uterine attachment sites are termed paraplacental sites. Uterine attachment sites are simple squamous while the paraplacental epithelium is simple columnar. Paraplacental cells have basal metachromatic vesicles and a dense array of apical cytoplasmic filaments. Immediately postpartum the uterine attachment sites, now termed uterine or placental scars, begin to remodel to a mucous epithelium for the next gestational cycle. Paraplacental cells slough off the apical filamentous portion, and sperm become embedded in the epithelium. Bundled sperm occur throughout gestation in the terminal zone of the oviducal gland. Sperm are not embedded in the terminal zone epithelium as in the uterus. Following sperm release from the uterus, the paraplacental epithelium reverts to a mucous epithelium for the next reproductive cycle. Fertilization is presumed to occur in the anterior oviduct above the oviducal gland. The physiological mechanisms that mediate sperm‐uterus attachment, release, and storage in the terminal zone of the oviducal gland are currently under investigation.J. Exp. Zool. 292:129–144, 2002. © 2002 Wiley‐Liss, Inc.
Scales of governance and environmental justice for adaptation and mitigation of climate change
Authors: Adger W.Neil 
Published: August 2002

AbstractGlobal climate change is a significant challenge to structures of governance at all temporal and spatial scales, particularly in the area of managing natural resources. Advances in understanding of the nature of observed and future climate change has led to a realization that significant future impacts are inevitable and increased efforts towards understanding the process of adaptation to the threatened impacts are required. This paper examines the issue of scale of governance relevant for adaptation. The UN Framework Convention on Climate Change is the primary mechanism for co‐ordinating international action on the threat of global climate change. The Convention process perceives adaptation as a further rationale for international transfers, in this case to compensate for and prepare for potential or realised impacts. This approach can be justified by recourse to the idea that enhancing sustainable development will enhance adaptive capacity and that planned activities are a key part of overall adaptation. But many adaptations to climate change will be spontaneous actions to perceived and actual risks in the environment. Thus institutional and economic parameters determine the underlying vulnerability and adaptive capacity of societies. I therefore argue that an understanding of adaptation processes allows interventions and planned adaptations at the most appropriate scales. I illustrate these arguments with reference to adaptation in agriculture and outline the insights from interdisciplinary development studies that can inform the climate change debates. Copyright © 2001 John Wiley & Sons, Ltd.
Ultrastructure of the embryonic snake skin and putative role of histidine in the differentiation of the shedding complex
Authors: Alibardi Lorenzo 
Published: August 2002

AbstractThe morphogenesis and ultrastructure of the epidermis of snake embryos were studied at progressive stages of development through hatching to determine the time and modality of differentiation of the shedding complex. Scales form as symmetric epidermal bumps that become slanted and eventually very overlapped. During the asymmetrization of the bumps, the basal cells of the forming outer surface of the scale become columnar, as in an epidermal placode, and accumulate glycogen. Small dermal condensations are sometimes seen and probably represent primordia of the axial dense dermis of the growing tip of scales. Deep, dense, and superficial loose dermal regions are formed when the epidermis is bilayered (periderm and basal epidermis) and undifferentiated. Glycogen and lipids decrease from basal cells to differentiating suprabasal cells. On the outer scale surface, beneath the peridermis, a layer containing dense granules and sparse 25–30‐nm thick coarse filaments is formed. The underlying clear layer does not contain keratohyalin‐like granules but has a rich cytoskeleton of intermediate filaments. Small denticles are formed and they interdigitate with the oberhautchen spinulae formed underneath. On the inner scale surface the clear layer contains dense granules, coarse filaments, and does not form denticles with the aspinulated oberhautchen. On the inner side surface the oberhautchen only forms occasional spinulae. The sloughing of the periderm and embryonic epidermis takes place in ovo 5–6 days before hatching. There follow beta‐, mesos‐, and alpha‐layers, not yet mature before hatching. No resting period is present but a new generation is immediately produced so that at 6–10 h posthatching an inner generation and a new shedding complex are forming beneath the outer generation. The first shedding complex differentiates 10–11 days before hatching. In hatchlings 6–10 h old, tritiated histidine is taken up in the epidermis 4 h after injection and is found mainly in the shedding complex, especially in the apposed membranes of the clear layer and oberhautchen cells. This indicates that a histidine‐rich protein is produced in preparation for shedding, as previously seen in lizard epidermis. The second shedding (first posthatching) takes place at 7–9 days posthatching. It is suggested that the shedding complex in lepidosaurian reptiles has evolved after the production of a histidine‐rich protein and of a beta‐keratin layer beneath the former alpha‐layer. J. Morphol. 251:149–168, 2002. © 2002 Wiley‐Liss, Inc.
Morphometry ofMacaca mulattaforelimb. II. Fiber‐type composition in shoulder and elbow muscles
Authors: Singh Kan , Melis Ellen H. , Richmond Frances J.R. , Scott Stephen H. 
Published: August 2002

AbstractThe present study examined the fiber‐type proportions of 22 muscles spanning the shoulder and/or elbow joints of threeMacaca mulatta. Fibers were classified as one of three types: fast‐glycolytic (FG), fast‐oxidative‐glycolytic (FOG), or slow‐oxidative (SO). In most muscles, the FG fibers predominated, but proportions ranged from 25–67% in different muscles. SO fibers were less abundant except in a few deep, small muscles where they comprised as much as 56% of the fibers. Cross‐sectional area (CSA) of the three fiber types was measured in six different muscles. FG fibers tended to be the largest, whereas SO fibers were the smallest. While fiber‐type size was not always consistent between muscles, the relative size of FG fibers was generally larger than FOG and SO fibers within the same muscle. When fiber CSA was taken into consideration, FG fibers were found to comprise over 50% of the muscle's CSA in almost all muscles. J. Morphol. 251:323–332, 2002. © 2002 Wiley‐Liss, Inc.
Quantitative analysis of MRI signal abnormalities of brain white matter with high reproducibility and accuracy
Authors: Wei Xingchang , Warfield Simon K. , Zou Kelly H. , Wu Ying , Li Xiaoming , Guimond Alexandre , Mugler John P. , Benson Randall R. , Wolfson Leslie , Weiner Howard L. , Guttmann Charles R.G. 
Published: August 2002

AbstractPurposeTo assess the reproducibility and accuracy compared to radiologists of three automated segmentation pipelines for quantitative magnetic resonance imaging (MRI) measurement of brain white matter signal abnormalities (WMSA).Materials and MethodsWMSA segmentation was performed on pairs of whole brain scans from 20 patients with multiple sclerosis (MS) and 10 older subjects who were positioned and imaged twice within 30 minutes. Radiologist outlines of WMSA on 20 sections from 16 patients were compared with the corresponding results of each segmentation method.ResultsThe segmentation method combining expectation‐maximization (EM) tissue segmentation, template‐driven segmentation (TDS), and partial volume effect correction (PVEC) demonstrated the highest accuracy (the absolute value of the Z‐score was 0.99 for both groups of subjects), as well as high interscan reproducibility (repeatability coefficient was 0.68 mL in MS patients and 1.49 mL in aging subjects).ConclusionThe addition of TDS to the EM segmentation and PVEC algorithms significantly improved the accuracy of WMSA volume measurements, while also improving measurement reproducibility. J. Magn. Reson. Imaging 2002;15:203–209. © 2002 Wiley‐Liss, Inc.
MRI monitoring of the thermal ablation of tissue: Effects of long exposure times
Authors: McDannold Nathan , Hynynen Kullervo , Jolesz Ferenc 
Published: August 2002

AbstractMRI‐derived thermometry based on the temperature‐dependence of the proton resonant frequency (PRF) is extremely sensitive to changes in tissue unrelated to temperature changes, including tissue swelling. This study investigated the maximum amount of time that this phase‐subtraction‐based method can be used to accurately monitor temperature changes in vivo. Long‐duration focused ultrasound sonications were delivered in rabbit thigh muscle with a phased‐array transducer, and the time that tissue swelling began was monitored. Tissue swelling began to occur at about one minute. The temperature correlated well with an implanted thermocouple up to this time. After this time, severe artifacts in the phase‐difference maps were observed. The thermal dose model predicted the extent of tissue damage well for subsequent one minute sonications. These results will have implications for MRI guidance of thermal therapies with long exposure times. J. Magn. Reson. Imaging 2001;13:421–427. © 2001 Wiley‐Liss, Inc.
Potential heating effect in the gravid uterus during MR HASTE imaging
Authors: Levine D. , Zuo C. , Faro C.B. , Chen Q. 
Published: August 2002

AbstractOur purpose was to evaluate if temperature changes occur in maternal or fetal tissues during HASTE imaging. Methods: Pregnant pigs were scanned with the HASTE technique, and temperatures were measured with phase maps and temperature probes inserted into the amniotic fluid and fetal brain. Results: Fiberoptic probes showed that no heating occurred in fetal tissues or amniotic fluid during HASTE imaging. Conclusion: Our current HASTE protocols do not deposit a significant amount of heat in the gravid uterus. J. Magn. Reson. Imaging 2001;13:856–861. © 2001 Wiley‐Liss, Inc.
In vitro validation of MR measurements of arterial pulse‐wave velocity in the presence of reflected waves
Authors: Stevanov Maja , Baruthio Joseph , Gounot Daniel , Grucker Daniel 
Published: August 2002

AbstractA magnetic resonance imaging projective velocity encoding sequence was used to determine the pulse‐wave velocity in an artery model. To this end, a well‐defined flow phantom simulating flow propagation in large arteries was used. In order to validate the measurement method in the presence of large reflected waves, these were deliberately created in the phantom. The projective sequence was applied to two measurement sites and the wave velocity was determined from the spatial and temporal separations of the foot of the velocity waveform. A theoretical model describing reflection and attenuation phenomena was compared with experimental velocity waveforms. The model showed that reflections and attenuation can explain the important changes in velocity waveforms. The model also confirmed that in the presence of reflecting waves, the foot of the waveform can be used as a characteristic point for measurements through changes in the waveform. J. Magn. Reson. Imaging 2001;14:120–127. © 2001 Wiley‐Liss, Inc.
Improved in‐gel approaches to generate peptide maps of integral membrane proteins with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Montfort Bart A. van , Canas Benito , Duurkens Ria , Godovac‐Zimmermann Jasminka , Robillard George T. 
Published: August 2002

AbstractThis paper reports studies of in‐gel digestion procedures to generate MALDI‐MS peptide maps of integral membrane proteins. The methods were developed for the membrane domain of the mannitol permease of E. coli. In‐gel digestion of this domain with trypsin, followed by extraction of the peptides from the gel, yields only 44% sequence coverage. Since lysines and arginines are seldomly found in the membrane‐spanning regions, complete tryptic cleavage will generate large hydrophobic fragments, many of which are poorly soluble and most likely contribute to the low sequence coverage. Addition of the detergent octyl‐β‐glucopyranoside (OBG), at 0.1% concentration, to the extraction solvent increases the total number of peptides detected to at least 85% of the total protein sequence. OBG facilitates the recovery of hydrophobic peptides when they are SpeedVac dried during the extraction procedure. Many of the newly recovered peptides are partial cleavage products. This seems to be advantageous since it generates hydrophobic fragments with a hydrophilic solubilizing part. In‐gel CNBr cleavage resulted in 5–10‐fold more intense spectra, 83% sequence coverage, fully cleaved fragments and no effect of OBG. In contrast to tryptic cleavage sites, the CNBr cleavage sites are found in transmembrane segments; cleavage at these sites generates smaller hydrophobic fragments, which are more soluble and do not need OBG. With the results of both cleavages, a complete sequence coverage of the membrane domain of the mannitol permease of E. coli is obtained without the necessity of using HPLC separation. The protocols were applied to two other integral membrane proteins, which confirmed the general applicability of CNBr cleavage and the observed effects of OBG in peptide recovery after tryptic digestion. Copyright © 2002 John Wiley & Sons, Ltd.
Differential IgM response to conformational and linear epitopes of parvovirus B19 VP1 and VP2 structural proteins
Authors: Manaresi Elisabetta , Zuffi Elisa , Gallinella Giorgio , Gentilomi Giovanna , Zerbini Marialuisa , Musiani Monica 
Published: August 2002

AbstractThe IgM immune response against conformational and linear epitopes of B19 structural proteins VP1 and VP2 was examined in serum samples with a suspect B19 infection to determine the most suitable antigen for use in IgM detection and also to evaluate a possible relationship between the course of B19 infection and the presence of epitope type‐specific IgM. The detection of IgM against conformational epitopes was performed by ELISA using undenatured VP1 and VP2 antigens whereas the detection of IgM against linear epitopes was performed by Western blot assays using denatured VP1 and VP2. IgM immune response against VP1 conformational epitopes appeared dominant, being detected in all serum samples positive for specific IgM, whereas IgM against VP2 linear antigen were found less frequently, being identified in less than half of the B19 IgM positive sera. In the examination of the course of infection, IgM against VP1 conformational epitopes appeared in the active phase of B19 infection at the same time and with the same frequency as IgM anti VP2 conformational epitopes and anti linear VP1 epitopes. IgM against VP1 conformational epitopes were seen to be long‐lasting because in the recent phase of infection they were still present when other specific IgM were absent. During the active phase of B19 infection, IgM against VP2 linear epitopes were less frequently found than other specific IgM and in the recent phase they underwent a rapid temporal diminution. The data demonstrate that a sensitive B19 IgM test needs to be performed in diagnostic laboratories by ELISA using conformational B19 antigens; Western blot assays can be used only as confirmatory tests using VP1 linear antigens. J. Med. Virol. 64:67–73, 2001. © 2001 Wiley‐Liss, Inc.
Brain remodeling due to neuronal and astrocytic proliferation after controlled cortical injury in mice
Authors: Kernie Steven G. , Erwin Trent M. , Parada Luis F. 
Published: August 2002

AbstractThe persistence of neural stem cells into adulthood has been an area of intense investigation in recent years. There is limited knowledge about how an acquired brain injury might affect the ability of neural precursor cells to proliferate and repopulate injured areas. In the present study we utilize a controlled cortical impact model of traumatic brain injury in adult mice and subsequent BrdU labeling to demonstrate that there is significant proliferation of neural precursors in response to traumatic brain injury in areas both proximal and distal to the injury site. The fate of the proximal proliferation is almost exclusively astrocytic at 60‐days post injury and demonstrates that newly generated cells make up much of the astrogliotic scar. Moreover, in areas more distal from the injury site, neurogenesis occurs within the granular layer of the dentate gyrus at a level more than five‐fold greater than in controls. These data demonstrate that neural proliferation plays key roles in the remodeling that occurs after traumatic brain injury and suggests a mechanism as to how functional recovery after traumatic brain injuries continues to occur long after the injury itself. J. Neurosci. Res. 66:317–326, 2001. © 2001 Wiley‐Liss, Inc.
Regulation and subcellular localization of the microtubule‐destabilizing stathmin family phosphoproteins in cortical neurons
Authors: Gavet Olivier , El Messari Saïd , Ozon Sylvie , Sobel André 
Published: August 2002

AbstractStathmin is a ubiquitous cytosolic phosphoprotein, preferentially expressed in the nervous system, and the generic element of a protein family that includes the neural‐specific proteins SCG10, SCLIP, and RB3 and its splice variants, RB3′ and RB3′′. All phosphoproteins of the family share with stathmin its tubulin binding and microtubule (MT)‐destabilizing activities. To understand better the specific roles of these proteins in neuronal cells, we performed a comparative study of their expression, regulation, and intracellular distribution in embryonic cortical neurons in culture. We found that stathmin is highly expressed (∼0.25% of total proteins) and uniformly present in the various neuronal compartments (cell body, dendrites, axon, growth cones). It appeared mainly unphosphorylated or weakly phosphorylated on one site, and antisera to specific phosphorylated sites (serines 16, 25, or 38) did not reveal a differential regulation of its phosphorylation among neuronal cell compartments. However, they revealed a subpopulation of cells in which stathmin was highly phosphorylated on serine 16, possibly by CaM kinase II also active in a similar subpopulation. The other proteins of the stathmin family are expressed about 100‐fold less than stathmin in partially distinct neuronal populations, RB3 being detected in only about 20% of neurons in culture. In contrast to stathmin, they are each mostly concentrated at the Golgi apparatus and are also present along dendrites and axons, including growth cones. Altogether, our results suggest that the different members of the stathmin family have complementary, at least partially distinct functions in neuronal cell regulation, in particular in relation to MT dynamics. © 2002 Wiley‐Liss, Inc.
TrkB dimerization during development of the prefrontal cortex of the macaque
Authors: Ohira Koji , Shimizu Keiko , Hayashi Motoharu 
Published: August 2002

AbstractTo date, two subtypes of TrkB, a BDNF receptor, have been described. One is full‐length TrkB (TK+), which has a tyrosine kinase‐containing intracellular domain. The other is truncated TrkB (TK−), which has a short intracellular domain lacking the tyrosine kinase. In this study, we investigated the dimerization of TrkB subtypes in the developing monkey prefrontal cortex by means of cross‐linking. At embryonic day 120, the TK+/TK+ and the 100 kDa/100 kDa homodimers were observed with BDNF stimulation. At the newborn stage, the TK+/TK+ and the TK−/TK− homodimers were observed with BDNF stimulation. At the adult stage, the TK−/TK− homodimer and the TK+/TK− heterodimer were formed by BDNF stimulation. The levels of all dimers increased in proportion to the concentration of BDNF. Moreover, the dimers were clearly formed within 5 min of treatment with BDNF. BDNF and NT‐4/5 induced the dimers, whereas NT‐3 formed slight dimers but NGF did not. Furthermore, anti‐BDNF antibody inhibited the TrkB dimerization. Moreover, the intercellular binding proteins of TrkB were not cross‐linked by BS3. Therefore, these results suggest that the change in dimerization among TrkB subtypes occurs during development of the monkey prefrontal cortex. J. Neurosci. Res. 65:463–469, 2001. © 2001 Wiley‐Liss, Inc.