bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determinants and Effects of Electrical Stimulation of the Inferior Interatrial Parasympathetic Plexus During Atrial Fibrillation
Authors: SOÓS PÁL , MERKELY BÉLA , HORVAT PÁL MAUROVICH , ZIMA ENDRE , SCHAUERTE PATRICK 
Published: August 2010

Introduction: Catheter stimulation of the inferior interatrial ganglionated parasympathetic plexus decreases the ventricular rate during atrial fibrillation (AF) in humans. However, the relatively high stimulation voltages might prevent implementation of neurostimulation in chronic implantable devices. From myocardial electrostimulation it is known that the required impulse energy and charge is lowest at the chronaxie time. In order to lower energy requirements for cardiac neurostimulation, the present study evaluates the impulse‐strength versus impulse‐duration relationship for a neurostimulation lead that was implanted into the inferior interatrial ganglionated plexus. Methods and Results: In nine dogs, permanent epicardial bipolar screw‐in electrodes were fixed in the inferior interatrial ganglionated plexus. AF was maintained via rapid atrial pacing. During AF, neural stimulation was performed at various frequencies (1–100 Hz), impulse durations (0.05–2 msec), and voltages (0.02–11.5 V). There was a linear correlation between R‐R interval lengthening and stimulus voltage (R = 0.99; P < 0.001) and a bell‐shaped relationship between stimulation frequency and negative dromotropic effect with maximum rate slowing at 30–50 Hz. The rheobase for a 50% R‐R interval prolongation during AF was 1.81 V and 2.72 V for high‐grade AVB yielding a chronaxie time of 0.14 msec and 0.18 msec, respectively. The impulse energy (charge) at the chronaxie time was 4–6 μJ (6–8 μC). Conclusions: Cardiac neurostimulation follows a chronaxie/rheobase behavior. Energy, charge, and voltage values needed to achieve significant negative dromotropic effects are within the limits of conventional cardiac pacemaker outputs, which may allow implementation of neurostimulation capabilities in current pacemaker technology.
Atrial Natriuretic Peptide Has Dose‐Dependent, Autonomically Mediated Effects on Atrial Refractoriness and Repolarization in Anesthetized Dogs
Authors: STAMBLER BRUCE S. , GUO GARY B. 
Published: August 2010

Introduction: Atrial natriuretic peptide (ANP) may alter electrophysiological properties of the heart and possibly have a role in arrhythmogenesis. However, previous studies have yielded conflicting results and have not fully considered whether ANP's cardiac electrophysiological effects are mediated via direct actions and/or indirectly via the autonomic nervous system. This study's aim was to establish whether ANP infused at pathophysiological and pharmacological doses has significant in vivo cardiac electrophysiological effects and to determine whether these effects are directly or autonomically mediated. Methods and Results: Electrophysiologic and hemodynamic effects of ANP infusion (human ANP at 15–600 ng/kg per minute) were examined in chloralose‐anesthetized dogs under conditions of varying autonomic blockade. In autonomically intact dogs (n = 12), low‐dose ANP (15 ng/kg per minute) shortened atrial effective refractory period (ERP) (P < 0.001) and monophasic action potential duration (MAPD90) (P < 0.05) at 600, 500, and 400 msec atrial paced cycle lengths and reduced right atrial pressure (P < 0.05) but did not alter mean arterial pressure. After either combined vagal and beta‐adrenergic blockade (vagotomy plus atropine plus propranolol, n = 7) or selective vagal blockade (n = 9), low‐dose ANP no longer altered atrial ERP or MAPD90. Higher ANP doses (150 and 600 ng/kg per minute) decreased mean arterial and right atrial pressures (P < 0.001) but did not alter atrial ERP, MAPD90, or other electrophysiological parameters including atrial fibrillation threshold, ventricular ERP, and MAPD90. Conclusion: ANP has dose‐dependent, autonomically mediated effects on atrial refractoriness and repolarization.
Stent Thrombosis Following 2 Drug‐Eluting Stent Implantations for Coronary Bifurcation Lesion: A Single‐Center Analysis
Authors: GAO ZHAN , XU BO , YANG YUEJIN , CHEN JILIN , QIAO SHUBIN , LI JIAN‐JUN , QIN XUEWEN , WU YONGJIAN , YAO MIN , YUAN JINQING , CHEN JUE , LIU HAIBO , DAI JUN , GAO RUN‐LIN 
Published: August 2010

Background:
The incidence of stent thrombosis (ST) following 2 drug‐eluting stent (DES) implantations for coronary bifurcation lesions needs to be identified.
Methods:
From April 2004 to April 2009, 705 consecutive patients with true bifurcation lesions who underwent a double stenting procedure with DES at the Fu Wai Hospital were analyzed.
Results:
Six (0.85%) patients had a definite ST, all of them had an early (4 acute and 2 subacute) definite ST. Probable ST occurred in 4 patients; in all of these cases, the event occurred early and was adjudicated because of the occurrence of sudden death within 30 days of the procedure. Therefore, a total of 10/705 (1.42%) patients had a definite or probable ST. Possible stent thrombosis was adjudicated only in 1 patient 371 days after the initial PCI in whom the cause of death was unexplained. Compared to the patients without definite and probable ST, patients with definite and probable ST were older, had more unstable angina, lower LVEF, and more left main bifurcation lesions (63.2 ± 8.9 vs. 56.8 ± 10.9 yrs; P = 0.049, 100% vs. 64.7%; P = 0.018, 50.6 ± 9.9 vs. 60.3 ± 12.4%; P = 0.019 and 70.0% vs. 36.1%; P = 0.043). Logistic analysis results indicated that only LVEF (OR 0.92, 95% CI 0.87–0.93; P = 0.017) was associated with definite and probable ST.
Conclusions:
The present study indicates that modern 2‐DES technique for bifurcation lesions was comparatively safe with a low incidence of ST. (J Interven Cardiol 2010;23:346–351)
On the Organization and Affinities of the Amoeba, Pompholyxophrys punicea Archer, Based on Ultrastructural Examination of Individual Cells from Wild Material1
Authors: Patterson David J. 
Published: August 2010

ABSTRACTThe genus Pompholyxophrys includes amoebae which have a spherical body, fine radiating pseudopodia, and a layer of adhering siliceous “perles.” These organisms are normally regarded as a type of heliozoon. Ultrastructural examination of P. punicea reveals that those characters associated with well characterized heliozoa, such as microtubular axonemes and extrusomes, are lacking. The species has much in common with nucleariid filose amoebae with which it, and the related genus Pinaciophora, are regarded as having affinities. The species P. punicea is rare, and this study was made possible by the application of techniques developed for the ultrastructural examination of single cells. The assessment of protistan diversity and interrelationships relies heavily on the use of ultrastructural characters. Although techniques that are based on the examination of a small number of individual cells have limitations, they do allow rare organisms to be included in the re‐evaluation of protistan systematics.
Morphological, Biometric, and Morphogenetic Comparison of Two Closely Related Species, Stylonychia vorax and S. pustulata (Ciliophora: Oxytrichidae)1
Authors: Wirnsberger Erna , Foissner Wilhelm , Adam Hans 
Published: August 2010

ABSTRACTDifferences in the morphology of Stylonychia vorax Stokes, 1885 and S. pustulata (Müller, 1786) Ehrenberg, 1838 recognizable in vivo are the shape, the ventral cirral pattern, the caudal cirri, and the mode of moving. The dorsal‐bristle complexes are distinguishable by the length of dorsal kinety four and the spaces among the pairs of basal bodies. When the ranges of variation of different populations and clones are compared by biometric analyses, S. vorax shows a relatively stable cortical pattern whereas in S. pustulata the cortical elements are regulated depending on the size of the body and the number of adoral membranelles. In S. vorax morphogenesis begins with a proliferation of basal bodies close to the transverse cirri. In contrast, in S. pustulata, the oral primordium appears de novo between the left marginal row and the postoral cirri. All other morphogenetic events are the same for both species. In proters and opisthes the six anlagen of the frontal‐ventral‐transverse cirri are of different origin and evolve independently. Three anlagen of the opisthe separate from the oral primordium, two originate from the right, and one from the left postoral cirrus. Three anlagen of the proter evolve from the posteriormost cirrus in the frontal area, one from the parental undulating membranes, one from the buccal cirrus, and one from the cirrus below the buccal cirrus. The anlagen one to six generate one, three, three, three, four, and four cirri. The characteristic arrangement of the undulating membranes and the participation of only two postoral cirri in the formation of primordia provide features that distinguish between the often confused genera Oxytricha and Stylonychia.
Rhoptry Secretion of Membranous Whorls by Plasmodium berghei Sporozoites1
Authors: Stewart Michael J. , Schulman Seymour , Vanderberg Jerome P. 
Published: August 2010

ABSTRACTElectron microscopy of sporozoites of the rodent malaria parasite, Plasmodium berghei, reveals electron‐dense multi‐laminate membranous whorls within components of the rhoptry‐microneme complex after fixation with tannic acid in conjunction with glutaraldehyde. This multilaminate material, which has a dark line to dark line periodicity of approximately 5 nm, appears to be secreted from the sporozoite since it is also found adhering to the sporozoite's external surface. The material may function in sporozoite gliding motility and in invasion of host cells.
Ichthyophthirius multifiliis (Ciliophora) Invasion of Gill Epithelium1
Authors: EWING MARGARET S. , KOCAN KATHERINE M. , EWING S. A. 
Published: August 2010

ABSTRACTThe sequence of morphologic events associated with Ichthyophthirius rnultifliis invasion of gill epithelium began in the theront with differentiation of secretory mucocysts and the perforatorium. After escaping from the cyst the theront, which stained intensely with Mallory' stain, sought a host. As it approached the host epithelium, the contents of the mucocysts were discharged, enveloping the ciliate in sticky material, which made initial contact with the host epithelium. Rapid penetration by the theront caused disruption of one or more host cells and resulted in a focal necrosis associated with the anterior margin of the ciliate. Within five minutes postexposure, the parasite completed its invasion of the epithelial layer and stained less intensely. The remnants of host cells disrupted during its entry surrounded the trophont until they were ingested by the parasite. Within 40 min postexposure, synthetic activity of the parasite appeared to increase as evidenced by an abundance of organelles, particularly ribosomes and crystalline mucocysts. At this point, the overlying host epithelium appeared normal.
Selection for and Enrichment of Non‐Discharge Mucocyst Variants of Tetrahymena thermophila 1,2
Authors: Tiedtke Arno 
Published: August 2010

ABSTRACTThe present protocol for selection for and enrichment of potential non‐discharge mucocyst variants of Tetrahymena thermophila is based on the ability of wild‐type cells to discharge their mucocyst contents simultaneously when stimulated with alcian blue 8 GS. Under appropriate ionic conditions, the discharged mucocyst contents form a capsule around each cell and prevent its locomotion. Non‐discharge variants unable to shed a capsule are assumed to retain their ability to swim and are simulated in this study by cells not induced to shed their capsule. For mass phenotype screening, the conditions for maximum capsule shedding were established for wild‐type cells. One hour starvation in Wagner's solution rendered 100% of the cells competent to shed a capsule when triggered with a 0.4% solution of alcian blue 8 GS. Decontamination of the shedding mixture by addition of egg albumin in a final concentration of 0.1% guaranteed survival of >95% of these cells that were now encapsulated, but allowed up to 5% of the cells to escape their capsule and swim freely. Cells with intact mucocysts and cells with emptied mucocysts were separated in reconstruction experiments by density‐gradient centrifugation in which 95% of the cells with intact mucocysts appeared in a discrete band. Using the same protocol, the efficiency of separation was tested with mixtures of morphologically marked (food vacuoles stained with India ink) and genetically marked (resistance to cycloheximide) cells. Using 1:1 mixtures of marked cells with intact mucocysts and cells with emptied mucocysts (or vice versa), the cells with intact mucocysts were efficiently separated from other cells; one cell with emptied mucocysts per 100 cells with intact mucocysts was found in the upper discrete gradient band.
Stage‐Dependent Protein Composition in the Life Cycle of Synchronous Ichthyophthirius multifiliis, a Ciliate Fish Parasite1
Authors: Pyle Stephen W. , Dawe Donald L. 
Published: August 2010

ABSTRACTThe sequential development of Ichthyophthirius multifiliis Fouquet, 1876 at 22°C was monitored from detachment from the fish through to infective tomites using one‐dimensional polyacrylamide gel electrophoresis. Methods are described for synchronizing I. multifiliis cells to permit the collection of large numbers of cells at stages during mitotic division. The electrophoretic protein patterns of the encysted stage differ from those of the tomite stage as well as from those of the other measured intervals.
The Full Schedule of Macronuclear DNA Synthesis is Not Required for Cell Division in Paramecium tetraurelia1 1
Authors: RASMUSSEN COLIN D. , CHING ADA S. L. , BERGER JAMES D. 
Published: August 2010

ABSTRACTMacronuclear DNA synthesis normally continues until late in the cell cycle in Paramecium; however, blockage of macronuclear DNA synthesis after 0.72 in the cell cycle does not alter the occurrence or timing of the subsequent cell division. When DNA synthesis is blocked after cells have reached the transition point, macronuclear DNA content at the following division is reduced to about 75% of the normal level. The point at which macronuclear DNA synthesis is no longer required for division corresponds to the beginning of micronuclear mitosis and the early stages of oral morphogenesis.
Species of the Coccidian Genus Alveocystis1
Authors: Levine Norman D. 
Published: August 2010

ABSTRACTPublications on the coccidia of certain invertebrates are reviewed and two new taxonomic‐nomenclatural combinations are introduced: Alveocystis macrocoronata (Lüling, 1942) n. comb., in hosts Priapulus caudatus and Halicryptus spinulosus (Priapuloidea); and A. gugleri (Wacha, 1981) n. comb., in Triodopsis albolabris (Mollusca).
Comparison of Ribosomal and Isozymic Phylogenies of Tetrahymenine Ciliates
Authors: NANNEY D. L. , MEYER E. B. , SIMON E. M. , PREPARATA R.‐M. 
Published: August 2010

ABSTRACTA recent analysis of sequence variations in ribosomal RNA's from 31 species of tetrahymenine ciliates groups them into 9 sets referred to as “ribosets.” These species associations are not well correlated with the distributions of distinctive morphological characteristics. The phylogenetic structure suggests that modem “pyriform” tetrahymenines may be paraphyletic survivors of primitive design and that the morphologically distinctive forms may include examples of convergent evolution of derived forms. Alternatively, the common ancestor may have been a polymorphic species that has lost its plasticity in some derived lineages. In an attempt to test the ribosomal phylogeny, we here compare it with a phytogeny based on isozymic variation. The main features of the ribosomal and isozymic phylogenies are similar. The carnivorous (macrostome‐forming) species are widely scattered in both, as are the bacteriophagous pyriform species. Isozymic and ribosomal analyses are optimally useful, however, in different contexts. Isozymic variations can distinguish species that are ribosomally identical. Ribosomal variations provide more secure evaluations of distant relationships.
Characterization and Cloning of Pneumocystis carinii Nucleic Acid
Authors: WORLEY MARK A. , IVEY MICHAEL H. , GRAVES DON C. 
Published: August 2010

ABSTRACTLarge numbers of Pneumocystis carinii (2 × 1010 nuclei) were isolated and separated from the lungs of immunosupprcsscd rats by an enzymaric (collagcnasc, hyaluronidasc and DN'asc) digestion procedure. The nucleic acid isolated from this P. cartnii‐cnnchcd preparation was characterized by melting point analysis and RNA‐sizing gels. The GC content of P. carinii DNA was approximately 33% while the rat DNA was 41.4%. In addition, RNA isolated from the P. curmii‐enrichcd preparation showed unique ribosomal RNA bands of 3.4 kb and 1.8 kb as compared with uninfected rat lung ribosoma! RNA. which banded at 4.8 and 1.9 kb. Following isolation and fragmentation by sonicaüon, the P. carinii D.VA fragments were inserted into the vector, λ gt‐11. The resultant library contained 1.1 × 105 phage, of which 40–45% hybridized to P. carinii DNA but not to rat DNA.
A Method for Isolation of RNA from Pneumocystis carinii
Authors: CUSHION MELANJE T. , BLASÉ MARIA AIRO , VVALZER PETER D. 
Published: August 2010

ABSTRACTToial RNA from Pneumocystis carinii obtained directly from the rat lung and from short term culture on A549 cells was evaluated for size and purity. An isolation procedure using guanidine isothiocyanate and lithium chloride was preferable to a hot phenol method. Host cells were eliminated by hypotonic lysis and a series of microfiltrations. Pneumocystis carinii were pretreated with Zymolyase for increased susceptibility to chaotropic agents. The major ribosomal species of P. carinii RNA migrated similarly to Saccharomyces cerevisiae rRNA. The 28s‐like species migrated well ahead of rat and A549 cell rRNA and weli behind the prokaryotic large rRNA species.
Proliferation of Pneumocystis Trophozoites in Human Lymph Nodes and in Nude Mice Lungs
Authors: MATSUMOTO YOSHITSUGU , FRENKEL JACOB K. , AIKAVVA MASAMICHI , YOSHIDA YUKIO 
Published: August 2010

ABSTRACTPneumocystis infection in athymic nude mice lungs showed a particularly high trophozoite to cyst ratio. A similar observation was obtained from a study of a patient with lymph node infection with Pneumocystis. Eosinophilic foamy masses in these sites were observed by light microscopy. With the electron microscope, the masses were seen to be composed of large aggregates of trophozoites. Cystic forms (precysl, cyst and empty cyst) were extremely scarce in comparison with the huge numbers of trophozoites. These cystic forms were mostly undergoing degeneration. These observations indicate that the mode of proliferation in both situations was predominantly asexual, that is, proliferation by trophozoites, suggesting that certain conditions may enhance asexual reproduction or depress the fonnation of cysts.
Adherence of Pneumocystis carinii in Lung Cells during in Vitro Cultivation
Authors: BURNSTEIN THEODORE , RHODES JAN , TUREK JOHN 
Published: August 2010

AbstractThis study describes an approach to cultivation of Pneumocystis carinii (I c) on 2 cell lines derived from lung (A549, human and L2, rat) with emphasis on the organisms which adhered to the cells. Immunofluorcsccnt staining was used for growth assays.
Dynamics of Pneumocystis carinii‐Specific Immune Complexes in AIDS Patients with P. carinii Pneumonia
Authors: PIFER LINDA L. 
Published: August 2010

ABSTRACTPneumocystis carinii‐specitic immune complexes were detected by immunoblot and enzyme‐linked immunosorbent assay (ELISA) in 53% of sera from Acquired Immunodeficiency Syndrome (AIDS) patients with P. carinii pneumonia (PCP). Resolution of glycoprotein antigenemia (50–55 kd = dominant species) appears to correlate with successful PCP drug therapy and recovery. An epitope map has been constructed from im‐munoblots of P. carinii hydrolysates and from human and murine scrum containing P. carinii antigens.
Surface Labeling of Pneumocystis carinii from in Vitro Culture
Authors: RADDING JEFFREY A. , ARMSTRONG MARTINE Y. K. , BOGUCKI M. SANDRA , RICHARDS FRANK F. 
Published: August 2010

SUMMARYPneumocystis carinii is an opportunistic pathogen of man, carried as a commensal in healthy subjects. It frequently causes a fatal pneumonia in the immunosupprcssed host. It is a major complication of HIV‐1 infection in man (AIDS). Using surface radioiodination of rat‐denved P. carinii trophozoites obtained from in vitro culture, a major surface glycoprotein (gp120) has been identified. The glycoprotein exhibits adherent behavior similar to that of the intact organism. Purification of gp120 by conventional methods was unsuccessful as the glycoprotein irreversibly bound lo numerous column matrices. A combination of gel chromatography and hydroxyapatile chromatography in sodium dodecylsulfaie v. as utilized to purify the glycoprotein. Some preliminary characterization of the glycoprotein is presented.
Analyses of Pneumocystis Fatty Acids
Authors: KANESHIRO EDNA S. , CUSHION MELANIET , WALZER PETER D. , JAYASIMHULU KOKA 
Published: August 2010

ABSTRACTThe major ester‐linked fatty acids of the total lipids extracted from Pneumocystis carinii isolated from the lungs of corticosteroid‐trcaicd rats were 16:0. 18:0, 18:1, 18:2 and 20:4. Others detected included 14:0, 16:1 and 22:4. The major sphingolipid fatty acids were 16:0, 18:0,22:0,24:0 and 24:1; others included 14:0, 18:1, 20:0, 23:0, 24:2 and 26:0. The total lipid fatty acid compositions of preparations from appropriate lung controls were similar to those of the organism.
Description of the Oocysts of Two New Species of Eimeria (Apicomplexa: Eimerüdae) from the Florida Manatee, Trichechus manatus (Sirenia: Trichechidae)
Authors: UPTON STEVE J. , ODELL DANIEL K. , BOSSART GREGORY D. , WALSH MICHAEL T. 
Published: August 2010

ABSTRACTTwo new species of Eimeria (Apicomplexa: Eimerüdae) are described from the feces of the Florida manatee, Trichechus manatus latirostrts (Sirenia: Trichechidae). Oocysts of Eimeria manatus n. sp. are spherical to subsphencal, 11.8 × 10.7 (10.5–13.5 × 9.0–13.5) μm, with a smooth, thin, bilayered wall; shape index (length/width) 1.1 (1.0–1.3). Micropyle and oocyst residuum absent; polar granule(s) usually present. Sporocysts are ovoid, 8.6 × 5.1 (8.0–9.5 × 5.0–5.5) μm, with thin, membrane–like walls and a knoblike Stieda body; shape index 1.7 (1.4–1.8). Sporozoites elongate, each with a large posterior refractile body. The sporocyst residuum consists of a small cluster or row of few to many small granules. Oocysts of Eimeria nodulosa n. sp. are spherical to subspherical, 15.6 × 14.7 (14.5–17.5 × 13.0–16.0) μm, with a distinctly bilayered wall; shape index 1.1 (1.0–1.2). Unsporulated and freshly sporulated oocysts often possess large, knob–like structures on the external surface of the oocyst wall that support a thin membrane or filament. Micropyle, oocyst residuum and polar granule absent. Sporocysts are ovoid, 10.6 × 5.9 (9.5–12.0 × 5.0–6.5) μm, with a smooth, thin wall and knob–like Stieda body; shape index 1.8 (1.5–2.1). Sporozoites granular and elongate, each with a large posterior refractile body. The sporocyst residuum consists of a loose aggregate or scattered mass of moderately sized granules.
Secretion of Acid Phosphatase by x4xenic Entamoeba histolytica NIH‐200 and Properties of the Extracellular Enzyme
Authors: AGRAWAL ANJU , PANDEY V. C. , KUMAR S. , SAGAR P. 
Published: August 2010

ABSTRACTEntamoeba histolytica (NIH‐200) secreted large amounts of acid phosphatase in its external environment when grown axenically in modified TPS‐II medium. Fractionation by DEAE‐cellulose chromatography of the precipitate obtained from the cell‐free medium at 60% ammonium sulfate saturation yielded 3 distinct peaks of enzyme activity. The enzyme in all the peaks showed resistance to tartrate but was inhibited by fluoride, cupnc chloride, ethylene diamine‐tetra acetic acid, ammonium molybdale and cysteine: however, enzyme associated with different peaks differed in its polyacrylamide gel electrophoretic profiles and behavior towards concanavalin A.