bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microvascular architecture of the rat choroid: Corrosion cast study
Authors: Bhutto Imran Ahmed , Amemiya Tsugio 
Published: September 2002

AbstractThis study presents the details of the microvasculature of the rat choroid visualized by scanning electron microscopy of vascular corrosion casts. Wistar Kyoto rats were anesthetized with intraperitoneal sodium pentobarbital. The vascular system was perfused with heparinized saline, and Mercox resin was injected into the cannulated carotid arteries. After polymerization of the resin, the vascular casts were macerated with potassium hydroxide, washed with water, and freeze dried. The casts were examined with a Hitachi S‐2360N scanning electron microscope (SEM). Corrosion casts of the entire choroidal vasculature revealed that the two long posterior ciliary arteries supplied the entire uveal vasculature. In the posterior choroid, these arteries formed five to seven branches on each side supplying the adjacent choriocapillaris. No interarterial or arteriovenous anastomoses were seen. The choriocapillaris appeared as a nonhomogeneous and nonlobular monolayer capillary network, consisting of dense honeycomb and irregular patterns. There are two distinct venous systems in the rat choroid. The venous blood from the central region, peripapillary choroid, and sometimes the optic nerve head drain into the posterior ciliary vein. The venous blood from the iris, ciliary body, anterior choroid, and half of the posterior choroid drain into the vortex veins. Corrosion casts and the SEM have shown details of the choroidal vascular architecture. These three‐dimensional observations indicate that the rat choroidal vasculature has different features from those of humans and other primates. Despite these interspecies differences, the establishment of a thorough baseline concept of choroidal vasculature should permit additional studies of the choroidal pathology and enable the proper interpretation of results from rat experimental models for extrapolation to humans. Anat Rec 264:63–71, 2001. © 2001 Wiley‐Liss, Inc.
Characterization and functions of the whitefly egg pedicel
Authors: Buckner James S. , Freeman Thomas P. , Ruud Rita L. , Chu Chang‐chi , Henneberry Thomas J. 
Published: September 2002

AbstractFor the silverleaf whitefly, Bemisia argentifolii (Bellows and Perring) (Homoptera: Aleyrodidae), scanning and transmission electron microscopic techniques were used to observe the characteristics of egg oviposition into both plant cells/tissues and artificial membranes, and to document the morphology of mature egg pedicles removed from the ovaries of females. The exterior of the distal portion of the pedicel consisted of a tangled array of fibrous structures (0.2–0.3 μm in diameter) that constituted about 20–25% of the outer diameter of the pedicel. The attachments of the fibers to the core of the pedicle suggested that the pedicel functions as the collector and conduit for water (vapor), and perhaps solute movement into the egg. Silverleaf whitefly eggs on membranes were incubated at various levels of relative humidity and the eggs were scored for egg hatch. At 98–100% rh, the percentage egg hatch was 86–98%. At lower humidity ranges of 0–20, 55–65, and 75–85% rh, none of the eggs hatched. Media (solute) uptake by silverleaf whitefly egg pedicels was determined by exposing the pedicel side of eggs oviposited on membranes to media solutions containing the high molecular weight polysaccharide, [14C]‐inulin. Solute uptake by the pedicel and movement into developing silverleaf whitefly eggs were demonstrated using [2‐14C]‐acetate, and assaying for radioactivity in hatched nymphs. These studies, using exposure of pedicels to relative humidity and radiolabeled materials, demonstrate that whitefly egg hatch is dependent upon water uptake by the pedicel, and that the pedicel has the ability to transport solutes into the developing egg. Arch. Insect Biochem. Physiol. 49:22–33, 2002. Published 2002 Wiley‐Liss, Inc.
Synthesis of lipids in the fat body of Gryllus bimaculatus: Age‐dependency and regulation by adipokinetic hormone
Authors: Lorenz Matthias W. 
Published: September 2002

AbstractThe free abdominal fat body of adult female Mediterranean field crickets, Gryllus bimaculatus, synthesizes lipids from [1‐14C]‐acetate in vitro. Up to an age of 12�h, the incorporation of acetate into lipids is very low and then rises to a maximum 24�h after adult emergence. Thereafter, the incorporation of acetate decreases to moderate levels at day 2 and then slowly decreases until day 30. The adipokinetic hormone of G. bimaculatus (Grb‐AKH) significantly inhibits the incorporation of acetate at a concentration of 10–11 M; maximum inhibition (approximately 95%) is reached at 10–8 M. The inhibiting effect of Grb‐AKH is fast, dose‐dependent, and reversible. The periovaric fat body shows a similar pattern of acetate incorporation, although rates of incorporation are lower; the incorporation can be inhibited by Grb‐AKH as well. The segmental abdominal fat body and the fat body from the head both incorporate acetate into lipids at low rates that cannot be inhibited significantly by AKH. Prepurified brain extracts significantly inhibit acetate incorporation by free abdominal fat bodies at a concentration of 0.1 brain equivalent. Allatostatins and crustacean cardioactive peptide, which are both present in cricket brains, are not responsible for this inhibiting effect. Octopamine causes a dose‐dependent inhibition of acetate incorporation whereas synephrine had no such effect. The inhibiting effect of Grb‐AKH on the formation of lipid stores in the fat body and its consequences for reproductive processes are discussed. Arch. Insect Biochem. Physiol. 47:198–214, 2001. © 2001 Wiley‐Liss, Inc.
Pharmacokinetics of E‐6087, a new anti‐inflammatory agent, in rats and dogs
Authors: Reinoso Raquel F. , Farrán Ramón , Moragón Trinidad , García‐Soret Antonio , Martínez Lluis 
Published: September 2002

AbstractThe pharmacokinetics of E‐6087, a newly developed cyclooxygenase‐2 inhibitor, was studied in rats and dogs after single oral and intravenous doses. In both animal species, E‐6087 was characterized by a long elimination half‐life (20–35 h), a low plasma clearance (0.10–0.22 l h−1 kg−1) and a relatively large volume of distribution (2–6 l kg−1). Oral bioavailability was lower in dogs than in rats whereas a faster elimination was found in rats. Multiple peaks were present regardless of administration route and animal species, suggesting the existence of enterohepatic circulation. Gender effect on the pharmacokinetics of E‐6087 was only found in rats, with greater exposure and longer elimination in females than in males. Food intake reduced the bioavailability (∼22%) with no apparent changes in the absorption rate. After oral dosing of 1, 5 and 25 mg kg−1 to rats, linearity was lost at the highest dose due to the low aqueous solubility of E‐6087. Drug absorption was improved by micronization. E‐6087 and E‐6132, (a pharmacologically active metabolite), showed different pharmacokinetics. The higher percentage of E‐6087 at early times suggests that E‐6087 is the main compound responsible for in vivo activity, although E‐6132 would contribute to the activity at later times. Copyright © 2001 John Wiley & Sons, Ltd.
Does neuronal loss in Parkinson's disease involve programmed cell death?
Authors: Andersen Julie K. 
Published: September 2002

AbstractRecently it has been hypothesized that apoptotic cell death is involved in several neuropathological conditions including Parkinson's disease (PD). Initial morphological studies assessing the presence of apoptosis in Parkinsonian brain tissues yielded mixed results. Based on more recent studies in human PD brains as well in animal and cell culture models of the disease, a picture is emerging, however, that strongly suggests that many of the molecular players thought to participate in this type of neuronal cell death are active in the disease. The task of researchers in the field is now to deduce how these players may be interacting with one another to bring about cell death in PD and to design effective therapies to interfere with these processes. BioEssays 23:640–646, 2001. © 2001 John Wiley & Sons, Inc.
Longterm stability of phase I and phase II enzymes of porcine liver cells in flat membrane bioreactors
Authors: Langsch Angelika , Bader Augustinus 
Published: September 2002

AbstractRecently, researchers have focused on the use of bioartificial liver devices to support patients with fulminant hepatic failure. Our team developed a cell‐based flat membrane bioreactor (FMB). In this, porcine liver cells were maintained in 3D‐coculture between two gel layers in a sandwich configuration for 3 weeks to study the influence of this bioreactor technique on the preservation of basic, not induced activities of phase I and phase II enzymes. First, the time and substrate dependencies of the following enzymes were measured: ethoxyresorufin‐O‐deethylase (EROD, CYP 1A1/1A2) and ethoxycoumarin‐O‐deethylase (ECOD, CYP 2B6) as phase I enzymes, and glutathione‐S‐transferase (GST), UDP‐glucuronosyltransferase (UGT) and sulfotransferase (ST) as phase II enzymes. To find optimal test conditions Michaelis‐Menten kinetics were calculated. Next, different potential inducers were tested to find out the most effective compounds. Based on these results, the basic, not induced levels of the different enzymes were determined in the flat membrane bioreactor. Furthermore, the response of these enzyme activities to the chosen inducers was investigated to examine whether the cells keep their ability for drug–drug interactions. Basic, not induced activities of both phase I enzymes and the phase II enzymes GST and UGT were maintained at nearly the initial levels during the complete period of study. In addition, it was possible to induce these enzymes twice or three times in a weekly interval. In contrast, the basic, not induced activity of ST increased during the first 10 days of culture. It stabilized then and was maintained steady. As in short‐term investigations, no reaction of the ST‐activity towards any inducer could be obtained. These results prove that porcine liver cells preserve their phase I and phase II activities and respond to inducing drugs over 3 weeks in culture. Therefore, the flat membrane bioreactor is not only suitable for investigating drug metabolism, drug–drug interactions, and enzyme induction but also for supporting liver functions. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 115–125, 2001.
Coronary angioplasty and Rotablator atherectomy trial (CARAT): Immediate and late results of a prospective multicenter randomized trial
Authors: Safian Robert D. , Feldman Ted , Muller David W.M. , Mason Denise , Schreiber Theodore , Haik Bruce , Mooney Michael , O'Neill William W. 
Published: September 2002

AbstractMechanical rotational atherectomy with the Rotablator is widely used for percutaneous coronary revascularization, but the ideal debulking strategy remains unknown. The purpose of this study was to compare the immediate and late results after Rotablator using two treatment strategies: Large burrs (burr/artery ratio of >0.7) to achieve maximal debulking (lesion debulking strategy) or small burrs (burr/artery ratio ≤ 0.7) to modify lesion compliance (lesion modification strategy). Two hundred twenty‐two patients at six centers were prospectively enrolled in this study and randomly assigned to large (n = 104 patients with 118 lesions) or small (n = 118 patients with 136 lesions) burrs. The primary endpoint was final diameter stenosis at the end of the procedure, and secondary endpoints included inhospital angiographic and clinical complications, and target lesion revascularization at 6 months. Baseline demographic and angiographic characteristics were similar. There were no differences in procedural success, the extent of immediate lumen enlargement, inhospital ischemic complications, or late target vessel revascularization. However, compared with small burrs, patients randomized to large burrs were more likely to experience serious angiographic complications (5.1% vs. 12.7%, P < 0.05) immediately after atherectomy. This study suggests that a routine lesion modification strategy employing small burrs (burr/artery ratio ≤ 0.7) achieves similar immediate lumen enlargement and late target vessel revascularization compared with a more aggressive debulking strategy (burr/artery ratio >0.7), but with fewer angiographic complications. Cathet Cardiovasc Intervent 2001;53:213–220. © 2001 Wiley‐Liss, Inc.
Evaluation of the percutaneous intramyocardial injection for local myocardial treatment
Authors: Rezaee Mehrdad , Yeung Alan C. , Altman Peter , Lubbe Dieter , Takeshi Suzuki , Schwartz Robert S. , Stertzer Simon , Altman John D. 
Published: September 2002

AbstractTherapeutic angiogenesis requires the induction of new blood vessel formation for the treatment of peripheral vascular and coronary artery disease. Efficacious application of this new therapy requires optimizing multiple factors, including the therapeutic agent, dosing, frequency of administration, and delivery modality. In this study, a helical needle drug infusion catheter was applied for optimal application of percutaneous intramyocardial delivery (PIMD). 125Iodine‐labeled albumin was injected by PIMD into the left ventricle myocardium in eight swine. After 1 hr, PIMD resulted in a high concentration of radiolabel at the treatment site; 16.4% ± 2.1% of delivered and 81.4% ± 2.6% of the total cardiac activity was concentrated at the site of delivery. The depth of needle penetration correlated with the myocardial retention of delivered protein. The myocardial retention of radiolabel in animals with shallow injections was 10.1% ± 0.8%, compared to 18.9% ± 3.3% retention after deep injections. The specific activity at the treatment site (radioactive counts per gram of tissue) was 115 ± 36, 226 ± 55, and 47 ± 10 times higher compared to liver, lung, and kidney, respectively. Continuous coronary sinus and aortic blood sampling indicates that within 15 min following intramyocardial injection, a significant amount of nonretained protein is found within the coronary sinus. This study defines some of the parameters that can affect optimal application of PIMD and demonstrates that PIMD is a safe and efficient method for local drug delivery. Cathet Cardiovasc Intervent 2001;53:271–276. © 2001 Wiley‐Liss, Inc.
Shape diversity among chick retina Müller cells and their postnatal differentiation
Authors: Anezary Lyazed , Medina Juan I. , Sánchez‐Nogueiro Jesüs , López‐Gallardo Meritxell , Prada Carmen 
Published: September 2002

AbstractIt is currently believed that in each vertebrate species Müller cells in the central retina constitutes a fairly homogeneous population from the morphologic point of view and that particularly the chick Müller cell attains full shape differentiation at prenatal stages. However, in this study of the chick retina, from day 1 to day 55 of life, we show that there is a large variety of Müller cell shapes and that many of them complete shape differentiation postnatally. We used a cell dissociation method that preserves the whole shape of the Müller cells. Unstained living and unstained fixed cells were studied by phase‐contrast microscopy, and fixed cells immunostained for intermediate filaments of the cytoskeleton were studied by fluorescence microscopy. Our results show that (1) Müller cell shapes vary in the origination of the hair of vitread processes, in the shape of the ventricular (outer or apical) process, in the presence or absence of an accessory process, as well as in the number and shape of processes leaving from the ventricular process at the level of the outer nuclear and outer plexiform layers (ONL/OPL); (2) during the first month of life, many Müller cells differentiate the portion of the ventricular process that traverses the ONL, most Müller cells differentiate the ONL/OPL processes, and all Müller cells differentiate the thin short lateral processes leaving from the vitread hair processes at the level of the inner plexiform layer (IPL). The number of cells differing in the shape of the ventricular process and that of cells with and without accessory process were estimated. The spatial relationship between the outer portion of the ventricular process of the Müller cell and the photoreceptor cells was also studied. Our results show that the branching of the ventricular process and the refinement of Müller cell shape is achieved without apparent participation of growth cones. We give a schematic view of how the branching of the ventricular process might take place and propose the size increase of photoreceptor soma as a factor responsible for this branching. J. Comp. Neurol. 438:32–49, 2001 © 2001 Wiley‐Liss, Inc.
Simulation study on ATM multiplexing of MPEG video sources
Authors: Feng J. , Lo K.‐T. 
Published: September 2002

AbstractIn this paper we study the performance of ATM multiplexing of homogeneous MPEG video sources. A source scheduling method is developed to improve the performance of ATM multiplexer for MPEG video sources. Simulation results show that the level of burstiness for the aggregated MPEG traffic is reduced and the network performance is enhanced. Based on the rationale of the source scheduling method, a simple but efficient bandwidth allocation algorithm is also derived for connection admission of MPEG video in an ATM multiplexer. Copyright © 2001 John Wiley & Sons, Ltd.
Ectonucleotidases: Some recent developments and a note on nomenclature
Authors: Zimmermann Herbert 
Published: September 2002

AbstractExtracellular nucleotides such as ATP, ADP, UTP, UDP, and also diadenosine polyphosphates act as signaling molecules and can be inactivated by hydrolysis via ectonucleotidases. A considerable number of surface‐located enzymes can potentially be involved in the extracellular hydrolysis pathway. These include the E‐NTPDase family (ectonucleoside triphosphate diphosphohydrolase family), the E‐NPP family (ectonucleotide pyrophosphatase/phosphodiesterase family), ecto‐5′‐nucleotidase, and alkaline phosphatases. In addition, activity of ectonucleoside diphosphokinase can interconvert extracellular nucleotides, and ATP can be used as a cosubstrate of ectoprotein kinase in the phosphorylation of surface‐located proteins. Members of the various ectonucleotidase families reveal overlapping substrate specificity and tissue distribution whose functional significance needs to be further elucidated. Considerable progress has been made in the past several years in characterizing novel enzyme species and their molecular and functional properties. First knock‐out mice reveal insight into physiological processes governed by the activity of specific ectonucleotidases. Together this work has led to a deeper understanding of the pathways of extracellular nucleotide metabolism, including their interplay with P2 and P1 receptors or also other physiological mechanisms. Drug Dev. Res. 52:44–56, 2001. © 2001 Wiley‐Liss, Inc.
Multiple growth factors regulate coronary embryonic vasculogenesis
Authors: Tomanek Robert J. , Zheng Wei , Peters Kevin G. , Lin Pengnian , Holifield Jennifer S. , Suvarna Padma R. 
Published: September 2002

AbstractMechanisms regulating coronary vascularization are not well understood. To test hypotheses regarding the influence of key growth factors and their interactions, we studied vascular tube formation (vasculogenesis) in collagen gels onto which quail embryonic ventricles were placed and incubated in the presence of growth factors or inhibitors. Vasculogenesis in this model is dependent on tyrosine kinase receptors, since tube formation was totally blocked by genestein. Tube formation was attenuated when anti‐bFGF or anti‐VEGF neutralizing antibodies were added to the medium and nearly completely inhibited when the both were added. The attenuation associated with anti‐VEGF was due primarily to a decrease in assembly of endothelial cells, while that associated with bFGF was primarily due to a reduction in endothelial cells. Soluble tie‐2, the receptor for angiopoietins, also had an inhibitory effect and, when added with either anti‐bFGF or anti‐VEGF, markedly attenuated tube formation. At optimal doses, tube formation was enhanced 6.5‐fold by bFGF and 2.5‐fold by VEGF over the controls. Each of these growth factors was dependent upon the other for optimal induction of tube formation, since neutralizing antibodies to one markedly reduced the potency of the other. VEGF potency was also markedly reduced when soluble tie‐2 was added to the medium. Tube formation was virtually totally blocked by exogenous TGF‐β at doses > 1 ng/ml, while neutralizing TGF‐β antibodies enhanced tube formation 2‐fold in the 30 ng–30 μg range. These data provide the first documentation of multiple growth factor regulation of coronary tube formation. © 2001 Wiley‐Liss, Inc.
The perichondrium plays an important role in mediating the effects of TGF‐β1 on endochondral bone formation
Authors: Alvarez Jesus , Horton Jennifer , Sohn Philip , Serra Rosa 
Published: September 2002

AbstractEndochondral bone formation is complex and requires the coordination of signals from several factors and multiple cell types. Thus, chondrocyte differentiation is regulated by factors synthesized by both chondrocytes and cells in the perichondrium. Previously, we showed that expression of a dominant‐negative form of the transforming growth factor β (TGF‐β) type II receptor in perichondrium/periosteum resulted in increased hypertrophic differentiation in growth plate chondrocytes, suggesting a role for TGF‐β signaling to the perichondrium in limiting terminal differentiation in vivo. Using an organ culture model, we later demonstrated that TGF‐β1 inhibits chondrocyte proliferation and hypertrophic differentiation by two separate mechanisms. Inhibition of hypertrophic differentiation was shown to be dependent on Parathyroid hormone‐related peptide (PTHrP) and expression of PTHrP mRNA was stimulated in the perichondrium after treatment with TGF‐β1. In this report, the hypothesis that the perichondrium is required for the effects of TGF‐β1 on growth and/or hypertrophic differentiation in mouse metatarsal organ cultures is tested. Treatment with TGF‐β1 inhibited expression of type X collagen mRNA in metatarsal cultures with the perichondrium intact. In contrast, hypertrophic differentiation as measured by expression of Type X collagen was not inhibited by TGF‐β1 in perichondrium‐free cultures. TGF‐β1 added to intact cultures inhibited BrdU incorporation in chondrocytes and increased incorporation in the perichondrium; however, TGF‐β1 treatment stimulated chondrocyte proliferation in metatarsals from which the perichondrium had been enzymatically removed. These results suggest that the TGF‐β1‐mediated regulation of both chondrocyte proliferation and hypertrophic differentiation is dependent upon the perichondrium. Thus, one or several factors from the perichondrium might mediate the way chondrocytes respond to TGF‐β1. © 2001 Wiley‐Liss, Inc.
Sensorless control of SRM based on a simple expression of magnetization characteristics
Authors: Kosaka Takashi , Matsui Nobuyuki , Saha Subrata , Takeda Yoji 
Published: September 2002

AbstractSwitched reluctance motors (SRM) have a simpler and more rugged construction than conventional ac motors, and hence are suitable for low‐cost variable‐speed drives in many industrial applications. However, the need to use a traditional position sensor for their control is one of the disadvantages of SRM from the standpoints of cost, size, and reliability. For practical use, there is a need for sensorless drive of SRM. This paper describes position‐sensorless control of SRM based on a simple expression of their nonlinear magnetization characteristics. Successful experiments using a 1.5‐kW, 5400‐rpm SRM with a 6/4 pole configuration have verified the practicability of the proposed sensorless control scheme. © 2001 Scripta Technica, Electr Eng Jpn, 137(2): 52–60, 2001