bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endothelin‐1 expression in long‐term cultures of fetal rat calvarial osteoblasts: Regulation by BMP‐7
Authors: Kitten Allison M. , Andrews Carrie J. 
Published: August 2002

AbstractEndothelin‐1 (ET‐1) is a vasoactive peptide that modulates bone metabolism via regulatory effects on osteoblasts, chondrocytes, and osteoclasts. While ET‐1 may circulate in the blood stream, tissue‐specific expression of this peptide is more physiologically relevant. In the present study we measured ET‐1 synthesis in sections of fetal rat calvaria (FRC) and in cultured FRC osteoblasts. Regulation of ET‐1 synthesis in FRC osteoblasts by bone morphogenetic protein‐7 (BMP‐7) and transforming growth factor‐β1 (TGF‐β1) also was examined. Immunohistochemical analysis revealed ET‐1 staining in calvarial osteoblasts, endothelial cells, and osteocytes. ET‐1 mRNA expression was detected in cultured FRC cells and ET‐1 peptide was present in conditioned media. During long‐term culture of FRC cells (26 days) ET‐1 peptide production rose sharply and peaked during the time of cellular proliferation (Days 0–3) then returned to baseline levels by Day 18, when mineralized nodules were forming. Treatment of FRC cells with BMP‐7 enhanced ET‐1 levels by three‐fold on Day 3 and enhanced nodule formation by 15‐fold on Day 26. To determine whether ET‐1 was involved in an autocrine manner in BMP‐7‐induced nodule formation, cells were cultured in the presence of BMP‐7 and BQ‐123, an ETA receptor antagonist. BQ‐123 had no effect on nodule formation in control or BMP‐7‐treated cells, indicating that osteoblast‐derived ET‐1 regulates other cell types in vivo during the bone formation process. © 2001 Wiley‐Liss, Inc.
Improvement of antibiotic production by increased oxygen solubility through the addition of perfluorodecalin
Authors: Elibol Murat 
Published: August 2002

AbstractA perfluorocarbon (PFC), namely perfluorodecalin, was added to fermentation medium to increase the medium's oxygen solubility. The antibiotic concentration obtained in the absence of PFC was 45 mg dm−3, whereas it was 90 mg dm−3 in the presence of 10% (v/v) PFC. On the other hand, biomass concentration decreased from 5.7 kg m−3 to 2.9 kg m−3 by adding 10% PFC. The use of PFC in the fermentation medium also reduced the formation of mycelial pellets. The values of the mass transfer coefficient, kLa, measured in the medium with PFC were found to be in the range of 122–175 h−1 during the active growth phase which were two to three times higher than those in the medium containing no PFC. Furthermore, the maximum oxygen uptake rates obtained at the stationary phase with and without PFC were 7 mmol dm−3 h−1 and 4.9 mmol dm−3 h−1, respectively. The actual effect of PFC on actinorhodin fermentation was demonstrated by applying different operational strategies to the system.© 2001 Society of Chemical Industry
Moisture sorption characteristics of waste activated sludge
Authors: Vaxelaire J 
Published: August 2002

AbstractNowadays the treatment of activated sludge often includes a thermal drying step. Data such as water vapour sorption isotherms and heat of sorption are required for good design and control of the drying processes. An equilibrium method was used to measure these data on domestic activated sludge, between 39 °C and 80 °C. The experimental investigation indicated that the nature of the sludge and its evolution (bulking sludge, anaerobic storage) do not affect the sorption isotherms. Experimental data were fitted to different well‐known models; the Oswin relationship gave the better fit. Based on sorption data the heat of sorption as a function of moisture content was determined.© 2001 Society of Chemical Industry
Incidence and importance of reflux in testicular veins of healthy men evaluated with color duplex sonography
Authors: Kocakoc Ercan , Kiris Adem , Orhan Irfan , Bozgeyik Zulkif , Kanbay Mustafa , Ogur Erkin 
Published: August 2002

AbstractPurposeReflux in the testicular veins plays a crucial role in the diagnosis of a varicocele. The aim of this study was to evaluate the incidence and the sonographic features—duration and velocity—of reflux in testicular veins of healthy men using color duplex sonography (CDS).MethodsHealthy male volunteers, 18–45 years old, whose physical examinations and semen analyses were normal, were recruited for this study. The maximum diameters of testicular veins during both normal respiration and Valsalva's maneuver were measured by CDS using a 7.5‐MHz linear‐array transducer. Veins greater than 2 mm in diameter were considered to be a varicocele, and the subjects in these cases were excluded from the analysis. In cases in which reflux was present, the velocity and duration of reflux in the testicular veins during Valsalva's maneuver were measured.ResultsSeventy men, whose mean (± standard deviation) age was 27 ± 7 years, were enrolled in this study. Fourteen of the 70 patients had a left varicocele and thus were excluded from the analysis. Of the 112 hemiscrotums in the remaining 56 patients, 61 (54%) had reflux induced by Valsalva's maneuver and 51 (46%) did not. Twenty‐two (39%) of refluxes were on the right side, with a mean duration of 1.1 ± 0.5 seconds, and a mean velocity of 4.2 ± 2.1 cm/second; 39 (70%) of the refluxes were on the left side, with a mean duration of 1.1 ± 0.5 seconds and a mean velocity of 4.9 ± 2.3 cm/second. The incidence of reflux was significantly higher on the left side (p = 0.003). The duration and velocity of the reflux did not differ significantly between the right and left sides. The difference in the testicular vein diameters between the right (1.3 ± 0.2 mm; n = 56) and left (1.6 ± 0.2 mm; n = 56) sides was statistically significant (p < 0.001).ConclusionsNormal‐sized testicular veins in healthy subjects had a remarkably high incidence of reflux induced by Valsalva's maneuver. The presence of reflux in subfertile men with normal testicular vein diameters is a diagnostic criterion, but it is necessary to quantify the reflux to prevent misdiagnosis of a varicocele and unnecessary surgery. The measurement of the duration and velocity limits of reflux in a large series of subjects may provide a reliable indicator for the diagnosis of varicocele. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:282–287, 2002; Published online in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/jcu.10068
Transabdominal sonography of the normal gastroesophageal junction in children
Authors: Esposito Francesco , Lombardi Romilda , Grasso Angela Coppolaro , Dolezalova Hana , Sodano Antonio , Tarantino Luciano , Giorgio Antonio 
Published: August 2002

AbstractPurposeBecause sonography identifies abnormalities of the gastroesophageal junction, it is essential to understand the normal sonographic anatomy. The aim of this study was to determine the normal sonographic appearance of the gastroesophageal junction and its variations and to provide measurements of the abdominal esophagus in asymptomatic, healthy children.MethodsIn this prospective study, 124 healthy children (75 boys and 49 girls), aged 2 days–12 years, underwent abdominal sonography. With the patient in a supine position, the transducer was placed under the xiphoid and the ultrasound beam was directed cephalad through the window of the left lobe of the liver. The length of the abdominal esophagus was measured from the point at which it penetrated the diaphragm to the gastroesophageal junction. The thickness was measured on the anterior wall at the midpoint of the abdominal esophagus.ResultsThe gastroesophageal junction was identified by sonography in all of the children. The mean length of the abdominal portion of the esophagus ranged from 18 mm in the newborns to 34 mm in children older than 6 years. The wall thickness ranged from 2.4 mm to 5.7 mm.ConclusionsOur results indicate that visualization of the gastroesophageal junction and measurement of the abdominal esophagus are readily achievable with real‐time sonography in healthy children. © 2001 John Wiley & Sons, Inc. J Clin Ultrasound 29:326–331, 2001.
4‐Hydroxynonenal, a lipid peroxidation byproduct of spinal cord injury, is cytotoxic for oligodendrocyte progenitors and inhibits their responsiveness to PDGF
Authors: Gard Anthony L. , Solodushko Victor G. , Waeg Georg , Majic Tamara 
Published: August 2002

AbstractOligodendroglial reactions to compression injury of spinal cord include apoptosis, secondary demyelination, and remyelination failure. Within hours after contusion, the membrane lipid peroxidation (MLP) byproduct, 4‐hydroxynonenal (HNE), increases rapidly in gray matter and thereafter in white matter tracts beyond the initial lesion level. Considering that HNE is a mediator and marker of neuronal MLP toxicity in various neurodegenerative conditions, the present study examined its effect on the regeneration potential of oligodendrocyte progenitors, as defined by their capacity to survive, proliferate and migrate in primary culture. Treatment of oligodendroblasts with HNE evoked a time‐ and dose‐dependent cytotoxicity resembling apoptosis at aldehyde concentrations known to be produced by neurons and achieved in tissue undergoing peroxidative injury. In addition, sublethal concentrations of HNE inhibited the mitogenic and chemotactic responses of more immature progenitors to platelet‐derived growth factor. These effects appear to be mediated in part by the formation of HNE adducts with progenitor proteins located within the plasma membrane and cytoplasmic compartments. Our data are the first to show that HNE can have direct, deleterious effects on oligodendrocyte precursors. The present study also suggests a mechanism by which the striking accumulation of HNE in white matter tracts surrounding the site of spinal cord compression injury and in other ischemic‐hypoxic insults associated with MLP could suppress the potential regenerative response of endogenous oligodendrocyte progenitor cells. Microsc. Res. Tech. 52:709–718, 2001. © 2001 Wiley‐Liss, Inc.
Tracking oligodendrocytes during development and regeneration
Authors: Chandross Karen J. , Champagne Benedicte , Auble Kathryn , Hudson Lynn D. 
Published: August 2002

AbstractOver the past decade, advances in strategies to tag cells have opened new avenues for examining the development of myelin‐forming glial cells and for monitoring transplanted cells in animal models of myelin insufficiency. The strategies for labelling glial cells have encompassed a range of genetic modifications as well as methods for directly attaching labels to cells. Genetically modified oligodendrocytes have been engineered to express enzymatic (e.g., β‐galactosidase, alkaline phosphatase), naturally fluorescent (e.g., green fluorescent protein), and antibiotic resistance (e.g., neomycin, zeomycin) reporters. Genes have been introduced in vivo and in vitro with viral or plasmid vectors to somatically label glial cells. To generate germ‐line transmission of tagged oligodendrocytes, transgenic mice have been created both by direct injection into mouse fertilized eggs and by “knock‐in” of reporters targetted to myelin gene loci in embryonic stem cells. Each experimental approach has advantages and limitations that need to be considered for individual applications. The availability of tagged glial cells has expanded our basic understanding of how oligodendrocytes are specified from stem cells and should continue to fill in the gaps in our understanding of how oligodendrocytes differentiate, myelinate, and maintain their myelin sheaths. Moreover, the ability to select oligodendrocytes by virtue of their acquired antibiotic resistance has provided an important new tool for isolating and purifying oligodendrocytes. Tagged glial cells have also been invaluable in evaluating cell transplant therapies in the nervous system. The tracking technologies that have driven these advances in glial cell biology are continuing to evolve and present new opportunities for examining oligodendrocytes in living systems. Microsc. Res. Tech. 52:766–777, 2001. Published 2001 Wiley‐Liss, Inc.
Microglia and prion disease
Authors: Brown David R. 
Published: August 2002

AbstractGliosis is one of the hallmarks of the prion diseases. Prion diseases are fatal neurodegenerative conditions of low incidence made famous by both the hypothesis that a protein acts as the infectious agent without involvement of nucleic acid and the speculative idea that a disease of cattle, BSE, has spread to humans from the ingestion of prion‐infected beef. Despite these unproved hypotheses, the aetiology of the prion diseases remains unsolved. The rapid degenerative course of the disease is preceded by a long incubation period with little or no symptoms. The rapid neurodegeneration in the disease follows from increased deposition of an abnormal isoform of a normal neuronal protein. Co‐incident with the appearance of this abnormal protein is the activation of large numbers of microglia. Studies in cell culture with both the abnormal prion protein and a peptide‐mimic suggest that neuronal degeneration occurs because of two concurrent effects. First, there is a reduction in neuronal resistance to toxic insults and, second, there is an increase in the production of toxic substances such as reactive oxygen species by microglia and a decrease in glutamate clearance by astrocytes. Microglia activated by the abnormal form of the prion protein also release cytokines, which stimulate changes in astrocytes such as proliferation. The implication of this is that microglia may play a major role in initiating the pathological changes in prion disease. This review discusses the role of microglia in these changes. Microsc. Res. Tech. 54:71–80, 2001. © 2001 Wiley‐Liss, Inc.
Catecholamines are present in larval Xenopus laevis: A potential source for cardiac control
Authors: Kloberg Angélica Jacobsson , Fritsche Regina 
Published: August 2002

AbstractChanges in noradrenaline (NA), adrenaline (A), and dopamine (DA) levels in the heart, kidneys, and whole body (without heart and kidneys) during embryonic development were investigated in the frog, Xenopus laevis using high‐performance liquid chromatography (HPLC). In addition, the presence of cells immunoreactive to tyrosine hydroxylase (TH), dopamine‐β‐hydroxylase (DBH) and/or phenylethanolamine‐N‐methyltransferase (PNMT) in the heart of Xenopus larvae was investigated using immunohistochemical techniques. The presence of nerve fibers was visualized using antibodies against acetylated tubulin (AcT). NA and DA concentrations in the heart were low and steady in NF 40–56, showed an increased value at NF 57, and decreased again in froglets. A trend toward higher concentrations of A was observed at NF 43–49 and NF 57. Cells immunoreactive to TH, DBH, and PNMT were found in the heart from NF 40, and the TH immunoreactive cells became more abundant in the whole heart at later stages. The presence of catecholamines in the non‐innervated larval heart together with the finding of TH/DBH/PNMT immunoreactive cells suggests that catecholamines are synthesized and stored in the heart and could therefore have a paracrine role in cardiac control in Xenopus larvae. Detectable concentrations of catecholamines were also found in kidneys and whole bodies (except heart and kidneys). Therefore, catecholamine‐producing cells outside the heart can be an important source of circulating catecholamines involved in adrenergic cardiac control in Xenopus larvae. J. Exp. Zool. 292:293–303, 2002. © 2002 Wiley‐Liss, Inc.
Membrane currents in the oocyte of the toad Bufo arenarum
Authors: Kotsias Basilio A. , Damiano Alicia E. , Godoy Sebastian , Assef Yanina , Ibarra Cristina , Cantiello Horacio F. 
Published: August 2002

AbstractThe amphibian oocyte cell model is widely used for heterologous expression of ionic channels and receptors. Little is known, however, about the physiology of oocyte cell models other than Xenopus laevis. In this study, the two‐electrode voltage clamp technique was used to assess the most common electrical patterns of oocytes of the South American toad Bufo arenarum. Basal membrane resistance, resting potential, and ionic currents were determined in this cell model. The oocyte transmembrane resistance was 0.35 MΩ, and the resting potential in normal saline was about –33 mV with a range between –20 mV and –50 mV. This is, to our knowledge, the first attempt to begin an understanding of the ion transport mechanisms of Bufo arenarum oocytes. This cell model may provide a viable alternative to the expression of ion channels, in particular those endogenously observed in Xenopus laevis oocytes. J. Exp. Zool. 292:411–415, 2002. © 2002 Wiley‐Liss, Inc.
Steroid enzyme gene expressions during natural and androgen‐induced gonadal differentiation in the rainbow trout, Oncorhynchus mykiss
Authors: Govoroun Marina , McMeel Oonagh Marie , D’Cotta Helena , Ricordel Marie‐José , Smith Terry , Fostier Alexis , Guiguen Yann 
Published: August 2002

AbstractIn fish, according to Yamamoto’s model, androgens would drive testis differentiation and estrogens ovarian differentiation. In order to study the implication of steroid enzymes in rainbow trout gonadal differentiation, we examined the expression of some steroid enzyme genes during natural differentiation (cholesterol side chain cleavage = P450scc, 17‐hydroxylase/lyase = P450c17, 3β‐hydroxysteroid dehydrogenase = 3βHSD) and androgen‐induced differentiation (P450scc, P450c17 , 3βHSD, aromatase = P450aro, and 11β‐hydroxylase = P45011β). Expressions of P450scc, 3βHSD, and P450c17 were all detected in male and female gonads at 55 days post‐fertilization (dpf), i.e., two weeks before histological differentiation. There were no differences in their expression level respective to the sex. The androgen treatment was carried out by administration of 11β‐hydroxyandrostenedione (11βOHΔ4) in genetic all‐female populations and the resulting sex ratios were found to be 100% male even at a low dosage of 1 mg/kg of food. Following 11βOHΔ4 treatment, only the expression of P450c17 was found to be sustained when compared with the female untreated control. In contrast, P450scc was clearly up‐regulated and 3βHSD and P450aro down‐regulated by the androgen treatment. P45011β gene expression remained low in gonads of androgen‐treated females, as it did in control untreated females. These results together demonstrate that steroidogenesis in rainbow trout is potentially active in pre‐differentiating gonads of both sexes, and that one of the masculinizing actions of androgens in the species may be to down‐regulate the female‐specific gonadal P450aro gene expression. However, in vivo androgen treatment in genetic females does not induce the same pattern of steroid gene expression as in genetic males. These data suggest that exogenous androgens might induce a male differentiation process with P450aro inhibition being one of the steps required. However, this process would not involve endogenously produced 11‐oxygenated androgens. J. Exp. Zool. 290:558–566, 2001. © 2001 Wiley‐Liss, Inc.
China's WTO accession, state enterprise reform, and spatial economic restructuring
Authors: Xiaobin Zhao Simon , Tong Christopher S. P. , Qiao Jiming 
Published: August 2002

AbstractChina's accession to the World Trade Organization (WTO) promises to have profound effects on the development of the nation's economy and on nationwide enterprise reorganization. This paper attempts to address the relationship between China's WTO accession and state enterprise reforms, and their impacts on the performance of China's spatial economy, including the possible rise and fall of several large national financial centres, such as Hong Kong, Beijing, Shanghai, Guangzhou and Shenzhen. It is argued that China's new international ties will enhance current enterprise reforms and promote changes in the existing pattern of enterprise organization, with enterprise mergers, acquisitions, takeover activity and the formation of large multinational corporations (MNCs) becoming dominant trends within China's industrial development. Alongside these changes, some economic sectors, such as information technology (IT) and advanced professional services are predicted to become concentrated in several national information ‘heartlands,’ each having its own well‐developed information infrastructure and other comparative advantages over traditional industrial centers. Meanwhile traditional industrial enterprises, while continuing to rely upon their pre‐assigned resource priorities, will certainly face fierce international competition in the turbulent global market. The spatial shift of production and trade undoubtedly requires that Chinese enterprises, especially those that are state‐owned, reorganize their production‐trade systems according to the global ‘rules of the game’. All of these changes, due to take effect imminently with China's WTO accession, will fundamentally restructure China's spatial economic landscape, including the creation of a new information heartland and hinterland that will in turn determine the life or death of the country's national financial centres. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis of 5‐methylthioribose specifically bitritiated at the 5‐C position
Authors: Viegas Christina , Zhang Qiang , Guillerm Danielle , Guillerm Georges 
Published: August 2002

AbstractAn efficient and reliable method for the preparation of bitritiated‐methylthioribose from a suitably protected 5‐ketoazido‐ribose derivative has been developed. This compound is an essential component in the assay of the microbial enzyme methylthioribose kinase, which is involved in the methionine salvage pathway from methylthioadenosine. Copyright © 2001 John Wiley & Sons, Ltd.
Microscopic anatomy of the eye of the deep‐diving Antarctic Weddell seal (Leptonychotes weddellii)
Authors: Welsch Ulrich , Ramdohr Sven , Riedelsheimer Bernd , Hebel Rudolf , Eisert Regina , Plötz Joachim 
Published: August 2002

AbstractThe microscopic anatomy of the eye of the Weddell seal was studied with various light and electron microscopic methods with a view to correlating morphological findings with the biology of this seal which is adapted to the extremes of the Antarctic environment and to extreme diving excursions into the lightless depths of the sea. In the retina an area centralis was found but no fovea centralis. The densely packed photoreceptors consist exclusively of highly differentiated rods, which in primates detect light at low intensity but have rather poor image discrimination. The ganglion cells are relatively scarce, suggesting a high degree of convergence of the light‐sensitive cells on the ganglion cells. The pigment epithelium is almost devoid of pigment granules. The extensive tapetum lucidum is about 400–500 μm thick and is composed of about 30 layers of specialized cells. The cornea is 650 (center) to 800–900 (periphery) μm thick. Its structure and glycosaminoglycan histochemistry correspond to that of other mammals. The iridocorneal angle is unusually deep and pervaded by an elaborate trabecular meshwork, which together with a complex canal of Schlemm can be correlated with the ability to absorb large amounts of fluid. The ciliary muscle and its antagonist, the membrane of Bruch, are poorly developed, suggesting relatively poor abilities of accommodation. The combination of a well‐developed tapetum lucidum, an unpigmented pigment epithelium, well‐developed rods, and a high number of rods converging on only few ganglion cells is obviously an adaptation to an extreme light sensitivity, enabling the animals to make use of the little light available in the deep sea. J. Morphol. 248:165–174, 2001. © 2001 Wiley‐Liss, Inc.