bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection of algal genotypes by three species of lichen fungi in the genusCladonia
Authors: Piercey-Normore Michele D
Published: August 2004

The lichen-forming fungal genus Cladonia P. Browne associates with green algae in the genus Trebouxia de Puymaly. Genetic structure of the algal symbionts in Cladonia gracilis (L.) Willd., Cladonia multiformis G. Merr., and C. rangiferina (L.) Nyl. was used to infer geographic patterns and symbiont associations. Algal genotypes were defined by restriction fragment length polymorphisms in the nuclear internal transcribed spacer rDNA from 115 samples of Cladonia collected from two geographic regions in Manitoba, Canada. Results suggested that two species of fungal symbiont were highly selective of the algal partner within given geographic areas, and one species was highly selective of the algal partner regardless of the geographic region. Different degrees of selectivity in three species suggested that even within the same genus, fungal selection for the algal partner may vary. In addition, DNA sequences from a subsample of 20 algal and 11 fungal specimens were used to determine phylogenetic relationships of each symbiont. Sequences of four group I intron-like insertions in the small subunit rDNA, two of which were newly reported for the genus Cladonia, were used to infer the fungal phylogeny. The intron phylogenies produced monophyletic species. Sequences of the internal transcribed spacer rDNA were used to infer the algal phylogeny. Cladonia gracilis and C. rangiferina were associated with three species of Trebouxia.Key words: selectivity, Cladonia, Trebouxia, phylogeny, geographic pattern.
40Ar/39Ar dating in the LochaberMulgrave area, northern mainland Nova Scotia: implications for timing of regional metamorphism and sediment provenance in the Late Devonian  Early Carboniferous Horton Group
Authors: Reynolds P H , Barr S M , White C E , Ténière P J
Published: August 2004

40Ar/39Ar dating of whole-rock samples and muscovite separates using age spectrum analysis, and of single muscovite grains using total fusion analysis, yields new insights into the timing of regional metamorphism and sediment provenance in the Late Devonian  Early Carboniferous Horton Group in the LochaberMulgrave area of Nova Scotia. The time of regional metamorphism is constrained to ca. 340335 Ma by whole-rock spectra from well-cleaved slate and shale samples from the lowermost Clam Harbour River and overlying Tracadie Road formations of the Horton Group. This ca. 340335 Ma event may have been the result of burial and deformation of the Horton Group by older volcanic and sedimentary rocks of the Guysborough Group, which were overthrust from the south as the result of development of a positive flower structure at a restraining bend along the CobequidChedabucto fault system, the boundary between the Meguma and Avalon terranes. Detrital muscovite ages of ca. 410380 and ca. 500 Ma were obtained from single-grain analysis and from spectral analysis of separated grains. Whole-rock spectra for two samples from a mylonitic metasedimentary unit in the Cape Porcupine Complex yielded plateau ages of 364 ± 4 and 367 ± 4 Ma, providing a likely source for ca. 370360 Ma detrital muscovite, ages that may be reflected in some of the age spectrum data. However, the Meguma terrane to the south is the most likely source for most of the detrital muscovite.
ON THE VOLUMES OF COMPLEX HYPERBOLIC MANIFOLDS WITH CUSPS
Authors: HWANG JUN-MUK
Published: August 2004

We study the problem of bounding the number of cusps of a complex hyperbolic manifold in terms of its volume. Applying algebra-geometric methods using Mumford's work on toroidal compactifications and its generalization due to N. Mok and W.-K. To, we get a bound which is considerably better than those obtained previously by methods of geometric topology.
THE INFLUENCE OF ATOMIC SUBSTITUTIONS AND SINTERING TEMPERATURE ON ELECTRICAL RESISTANCE AND IRREVERSIBILITY LINE OF (Bi,Pb):2223 BULK SUPERCONDUCTORS
Authors: POP A. V. , ILONCA G. , POP M. , MARCONI D.
Published: August 2004

Superconducting ceramic samples ( Bi , Pb ):2223 (sample V) and ( Bi )( Pb ),( Sr , Ba ):2223 (samples S1 and S2) were investigated by electrical resistance and AC magnetic susceptibility measurements. The intergrain critical current density J cJ (T) dependence near T c obtained from imaginary AC susceptibility data agrees with the assumption of SNS intergrain junctions, and are sensitive to the compounds stoichiomerty and thermal treatments. The crossover from linear to nonlinear dependence of T p (H AC ) of irreversible line (IL) observed in all samples, was discussed based on the modification of Josephson medium in the Muller model.
CAR-ORIENTED MEAN-FIELD THEORY REVISITED
Authors: CHIEN YU-FUNG , HUANG DING-WEI
Published: August 2004

We study the Car-Oriented Mean-Field approximation (COMF) to the Nagel–Schreckenberg model in the case of v max =3. The self-consistent equations are obtained. The solution is reached by the method of iteration. When the stochastic noise is small, the numerical simulations can be well described by the mean-field theory. When the stochastic noise is large, the flux around critical density is overestimated. The overshooting of the free flow can be attributed to the collective effect of the stochastic noise.
APPLICATION OF PAIR COHERENT STATES IN QUANTUM INFORMATION PROCESSES
Authors: WU RU-KUAN , LI SHANG-BIN , WANG QIN-MEI , XU JING-BO
Published: August 2004

We investigate the entanglement of pair coherent states in the phase damping channel by adopting the relative entropy of entanglement and propose a protocol of teleportation via pair coherent states. The fidelity of the protocol is then analyzed and the influence of phase damping on the teleportation fidelity examined.
ON RESIDUAL FINITENESS OF GRAPHS OF NILPOTENT GROUPS
Authors: RAPTIS E. , TALELLI O. , VARSOS D.
Published: August 2004

Here we characterize the residually finite groups G which are the fundamental groups of a finite graph of finitely generated torsion-free nilpotent groups. Namely we show that G is residually finite if and only if for each edge group of the graph of groups the two edge monomorphisms differ essentially by an isomorphism of certain subgroups of the Mal'cev completion of the corresponding vertex groups.
ON TORSION IN FACTORS OF POLYNILPOTENT SERIES OF A GROUP WITH A SINGLE RELATION
Authors: GUPTA C. K. , ROMANOVSKI N. S.
Published: August 2004

Let G=F/rF be a group with a single defining relation, r∈Fkm\Fk,m+1, Fij the term of some polynilpotent series of the free group F. We prove: the factors of the corresponding polynilpotent series of the group G are torsion free if and only if r is not a proper power of any element of F modulo Fk,m+1. We also give a description of the lower central series of a group F/[R,R] when F/R is a nilpotent group with torsion free lower central factors.
KOLMOGOROV SYSTEMS AND ANOSOV SYSTEMS IN QUANTUM THEORY
Authors: NARNHOFER H.
Published: August 2004

In analogy to classical systems, quantum K-systems and quantum Anosov systems are defined. Their relation especially for modular systems is discussed as well as the consequences on clustering properties. Examples for such systems in the framework of quantum field theory and one-dimensional theories are offered.
VALIDITY OF THE DIRECT RELATION BETWEEN THE FRACTURE MECHANICS PARAMETERS, K AND G, IN THE CASE OF BONE
Authors: PARUCHURU SATYA PRASAD , RAO KOGANTI MOHAN , WANG XIAODU , AGRAWAL C. M.
Published: August 2004

The critical values of stress intensity factor and energy release rate (KIc, GIc) are important fracture mechanics parameters used in the characterization of bone fracture, assessment of bone quality, and prosthesis design. There exists, a direct relationship between stress intensity factor, K and energy release rate, G that holds good for linear elastic, isotropic, and homogeneous materials. As bone is anisotropic and non-homogeneous, whether or not the relationship is still valid is an important factor. Bone is a brittle material and if it is tested for a particular crack orientation and at a particular sampling site, it may behave as a linear elastic, isotropic, and homogeneous material. The present work verifies the direct relation between K and G of bone in the case of tangential cracks.
ORGANIZATIONAL INNOVATION: A MULTI-LEVEL DECISION-THEORETIC PERSPECTIVE
Authors: KESSLER ERIC H.
Published: August 2004

This paper presents a multi-level decision making perspective of the innovation process. First, by considering the innovation process as a type of decision. Second, by viewing innovation as composed of multiple decision processes. Third, by analyzing innovation in terms of decision domains that "enable" innovation and that "execute" innovation. Fourth, by discussing how decision factors act as determinants of innovation. Implications are discussed and propositions are offered which consider several critical tasks in the successful management of innovation decision process(es).
Contribution of coupling between human myometrial β2-adrenoreceptor and the BKCa channel to uterine quiescence
Authors: Chanrachakul Boonsri , Broughton Pipkin Fiona , Khan Raheela N.
Published: August 2004

The β2-adrenergic receptor (β2-AR) and the large-conductance Ca2+-activated K+ (BKCa) channel have been shown, separately, to be involved in mediating uterine relaxation. Our recent studies reveal that the levels of both β2-AR and BKCa channel proteins in pregnant human myometrium decrease by ∼50% after the onset of labor. We present direct evidence in support of a structural and functional association between the β2-AR and the BKCa channel in pregnant human myometrium. Localization of both proteins is predominantly plasmalemmal, with 60% of β2-AR colocalizing with the BKCa channel. Coimmunoprecipitation studies indicate that BKCa and β2-AR are structurally linked by direct protein-protein interactions. Functional correlation was confirmed by experiments of human myometrial contractility in which the BKCa channel blocker, paxilline, significantly antagonized the relaxant effect of the β2-AR agonist ritodrine. These novel findings provide an insight into the coupling between the β2-AR and BKCa channel and may have utility in the application of this signaling cascade for therapeutic potential in the management of preterm labor.
Erythropoietin-modulated calcium influx through TRPC2 is mediated by phospholipase Cγ and IP3R
Authors: Tong Qin , Chu Xin , Cheung Joseph Y. , Conrad Kathleen , Stahl Richard , Barber Dwayne L. , Mignery Gregory , Miller Barbara A.
Published: August 2004

In the present study, we examined the mechanisms through which erythropoietin (Epo) activates the calcium-permeable transient receptor potential protein channel (TRPC)2. Erythroblasts were isolated from the spleens of phenylhydrazine-treated mice, and Epo stimulation resulted in a significant and dose-dependent increase in intracellular calcium concentration ([Ca2+]i). This increase in [Ca2+]i was inhibited by pretreatment with the phospholipase C (PLC) inhibitor U-73122 but not by the inactive analog U-73343, demonstrating the requirement for PLC activity in Epo-modulated Ca2+ influx in primary erythroid cells. To determine whether PLC is involved in the activation of TRPC2 by Epo, cell models were used to examine this interaction. Single CHO-S cells that expressed transfected Epo receptor (Epo-R) and TRPC2 were identified, and [Ca2+]i was quantitated. Epo-induced Ca2+ influx through TRPC2 was inhibited by pretreatment with U-73122 or by downregulation of PLCγ1 by RNA interference. PLC activation results in the production of inositol 1,4,5-trisphosphate (IP3), and TRPC2 has IP3 receptor (IP3R) binding sites. To determine whether IP3R is involved in Epo-R signaling, TRPC2 mutants were prepared with partial or complete deletions of the COOH-terminal IP3R binding domains. In cells expressing TRPC2 IP3R binding mutants and Epo-R, no significant increase in [Ca2+]i was observed after Epo stimulation. TRPC2 coassociated with Epo-R, PLCγ, and IP3R, and the association between TRPC2 and IP3R was disrupted in these mutants. Our data demonstrate that Epo-R modulates TRPC2 activation through PLCγ; that interaction of IP3R with TRPC2 is required; and that Epo-R, TRPC2, PLCγ, and IP3R interact to form a signaling complex.
Activation of rat mesenteric arterial KATP channels by 11,12-epoxyeicosatrienoic acid
Authors: Ye Dan , Zhou Wei , Lee Hon-Chi
Published: August 2004

Epoxyeicosatrienoic acids (EETs), the cytochrome P-450 epoxygenase metabolites of arachidonic acid, are candidates of endothelium-derived hyperpolarizing factors. We have previously reported that EETs are potent activators of cardiac ATP-sensitive K+ (KATP) channels, but their effects on the vascular KATP channels are unknown. With the use of whole cell patch-clamp techniques with 0.1 mM ATP in the pipette and holding at −60 mV, freshly isolated smooth muscle cells from rat mesenteric arteries had small glibenclamide-sensitive currents at baseline (13.1 ± 3.9 pA, n = 5) that showed a 7.2-fold activation by 10 μM pinacidil (94.1 ± 21.9 pA, n = 7, P < 0.05). 11,12-EET dose dependently activated the KATP current with an apparent EC50 of 87 nM. Activation of the KATP channels by 500 nM 11,12-EET was inhibited by inclusion of the PKA inhibitor peptide (5 μM) but not by the inclusion of the PKC inhibitor peptide (100 μM) in the pipette solution. These results were corroborated by vasoreactivity studies. 11,12-EET produced dose-dependent vasorelaxation in isolated small mesenteric arteries, and this effect was reduced by 50% with glibenclamide (1 μM) preincubation. The 11,12-EET effects on vasorelaxation were also significantly attenuated by preincubation with cell-permeant PKA inhibitor myristoylated PKI(14–22), and, in the presence of PKA inhibitor, glibenclamide had no additional effects. These results suggest that 11,12-EET is a potent activator of the vascular KATP channels, and its effects are dependent on PKA activities.
Genetic manipulation of calcium-handling proteins in cardiac myocytes. II. Mathematical modeling studies
Authors: Coutu Pierre , Metzger Joseph M.
Published: August 2004

We developed a mathematical model specific to rat ventricular myocytes that includes electrophysiological representation, ionic homeostasis, force production, and sarcomere movement. We used this model to interpret, analyze, and compare two genetic manipulations that have been shown to increase myocyte relaxation rates, parvalbumin (Parv) de novo expression, and sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2a) overexpression. The model was used to seek mechanistic insights into 1) the relative contribution of two mechanisms by which SERCA2a overexpression modifies Ca2+ sequestration, i.e., more pumps and an increase in the SERCA2a-to-phospholamban ratio, 2) the mechanisms behind postrest potentiation and how Parv and SERCA2a influence this response, and 3) why Parv myocytes retain their fast kinetics when endogenous SERCA2a is partially impaired by thapsigargin (a condition used to mimic diastolic dysfunction). The model was also utilized to predict whether Parv metal-binding characteristics might be modified to improve diastolic and systolic functions and whether Parv or SERCA2a might affect diastolic Ca2+ levels and myocyte energetics. One outcome of the model was to demonstrate a higher peak and total ATP consumption in SERCA2a myocytes and more even distribution of ATP throughout the cardiac cycle in Parv myocytes. This may have implications for failing hearts that are energetically compromised.
ANG II type 2 receptor regulates smooth muscle growth and force generation in late fetal mouse development
Authors: Perlegas Demetra , Xie Hui , Sinha Sanjay , Somlyo Avril V. , Owens Gary K.
Published: August 2004

Although evidence from culture studies implicates the angiotensin II (ANG II) type 2 receptor (AT2R) in the regulation of growth and differentiation of arterial smooth muscle (SM) cells (SMC), the lack of its expression in adult arteries has precluded direct investigation of its role in vivo. The goal of the present study was to determine the role of AT2R in the control of fetal SMC growth, contractility, and differentiation during vascular development. Determination of isometric tension in fetal aortas showed potentiated ANG II-induced contraction by treatment with the selective AT2R antagonist PD-123319, demonstrating the presence of functional AT2Rs that mediate reduced force development in vascular SMC. In direct contrast to numerous cell culture studies, proliferation indexes were decreased rather than increased in aortic SMC of fetal homozygous AT2R knockout compared with wild-type or heterozygous knockout mice. Experiments using SMC tissues from heterozygous female AT2R knockout mice, which are naturally occurring chimeras for AT2R expression, showed that AT2R mRNA expression was exactly 50% of that of wild type. This indicated that loss of AT2R expression did not confer a selective advantage or disadvantage for SMC lineage determination and expansion. Real time RT-PCR analyses showed no significant difference in expression of SM-α-actin, SM myosin heavy chain, and myocardin in various SM tissues from all three genotypes, suggesting that knockout of AT2R had no effect on subsequent SMC differentiation. Taken together, results indicate that functional AT2R are expressed in fetal aorta and mediate reduced force development but do not significantly contribute to regulation of SMC differentiation.
Comparison of oxygen uptake kinetics during knee extension and cycle exercise
Authors: Koga Shunsaku , Poole David C. , Shiojiri Tomoyuki , Kondo Narihiko , Fukuba Yoshiyuki , Miura Akira , Barstow Thomas J.
Published: August 2004

The knee extension exercise (KE) model engenders different muscle and fiber recruitment patterns, blood flow, and energetic responses compared with conventional cycle ergometry (CE). This investigation had two aims: 1) to test the hypothesis that upright two-leg KE and CE in the same subjects would yield fundamentally different pulmonary O2 uptake (pV̇o2) kinetics and 2) to characterize the muscle blood flow, muscle V̇o2 (mV̇o2), and pV̇o2 kinetics during KE to investigate the rate-limiting factor(s) of pV̇o2 on kinetics and muscle energetics and their mechanistic bases after the onset of heavy exercise. Six subjects performed KE and CE transitions from unloaded to moderate [< ventilatory threshold (VT)] and heavy (>VT) exercise. In addition to pV̇o2 during CE and KE, simultaneous pulsed and echo Doppler methods, combined with blood sampling from the femoral vein, were used to quantify the precise temporal profiles of femoral artery blood flow (LBF) and mV̇o2 at the onset of KE. First, the gain (amplitude/work rate) of the primary component of pV̇o2 for both moderate and heavy exercise was higher during KE (∼12 ml·W−1·min−1) compared with CE (∼10), but the time constants for the primary component did not differ. Furthermore, the mean response time (MRT) and the contribution of the slow component to the overall response for heavy KE were significantly greater than for CE. Second, the time constant for the primary component of mV̇o2 during heavy KE [25.8 ± 9.0 s (SD)] was not significantly different from that of the phase II pV̇o2. Moreover, the slow component of pV̇o2 evident for the heavy KE reflected the gradual increase in mV̇o2. The initial LBF kinetics after onset of KE were significantly faster than the phase II pV̇o2 kinetics (moderate: time constant LBF = 8.0 ± 3.5 s, pV̇o2 = 32.7 ± 5.6 s, P < 0.05; heavy: LBF = 9.7 ± 2.0 s, pV̇o2 = 29.9 ± 7.9 s, P < 0.05). The MRT of LBF was also significantly faster than that of pV̇o2. These data demonstrate that the energetics (as gain) for KE are greater than for CE, but the kinetics of adjustment (as time constant for the primary component) are similar. Furthermore, the kinetics of muscle blood flow during KE are faster than those of pV̇o2, consistent with an intramuscular limitation to V̇o2 kinetics, i.e., a microvascular O2 delivery-to-O2 requirement mismatch or oxidative enzyme inertia.
High sodium chloride intake decreases betaine-homocysteineS-methyltransferase expression in guinea pig liver and kidney
Authors: Delgado-Reyes Cassandra V. , Garrow Timothy A.
Published: August 2004

Betaine-homocysteine S-methyltransferase (BHMT) is the only enzyme known to catabolize betaine. In addition to being a substrate for BHMT, betaine also functions as an osmoprotectant that accumulates in the kidney medulla under conditions of high extracellular osmolarity. The mechanisms that regulate the partitioning of betaine between its use as a methyl donor and its accumulation as an osmoprotectant are not completely understood. The aim of this study was to determine whether BHMT expression is regulated by salt intake. This report shows that guinea pigs express BHMT in the liver, kidney, and pancreas and that the steady-state levels of BHMT mRNA in kidney and liver decrease 68% and 93% in guinea pigs consuming tap water containing high levels of salt compared with animals provided untreated tap water. The animals consuming the salt water also had ∼50% less BHMT activity in the liver and kidney, and steady-state protein levels decreased ∼30% in both organs. Pancreatic BHMT activity and protein levels were unaffected by the high salt treatment. The complex mechanisms involved in the downregulation of hepatic and renal BHMT expression in guinea pigs drinking salt water remain to be clarified, but the physiological significance of this downregulation may be to expedite the transport and accumulation of betaine into the kidney medulla under conditions of high extracellular osmolarity.
Quantitative models of the rat pulmonary arterial tree morphometry applied to hypoxia-induced arterial remodeling
Authors: Molthen Robert C. , Karau Kelly L. , Dawson Christopher A.
Published: August 2004

Little is known about the constituent hemodynamic consequences of structural changes that occur in the pulmonary arteries during the onset and progression of pulmonary arterial remodeling. Many disease processes are known to be responsible for vascular remodeling that leads to pulmonary arterial hypertension, cor pulmonale, and death. Histology has been the primary tool for evaluating pulmonary remodeling, but it does not provide information on intact vascular structure or the vessel mechanical properties. This study is an extension of our previous work in which we developed an alternative imaging technique to evaluate pulmonary arterial structure. The lungs from Sprague-Dawley rats were removed, perfusion analysis was performed on the isolated lungs, and then an X-ray contrast agent was used to fill the arterial network for imaging. The lungs were scanned over a range of intravascular pressures by volumetric micro-computed tomography, and the arterial morphometry was mapped and measured in the reconstructed isotropic volumes. A quantitative assessment of hemodynamic, structural, and biomechanical differences between rats exposed for 21 days to hypoxia (10% O2) or normoxia (21.0% O2) was performed. One metric, the normalized distensibility of the arteries, is significantly ( P < 0.001) larger [0.025 ± 0.0011 (SE) mmHg−1] ( n = 9) in normoxic rats compared with hypoxic [0.015 ± 0.00077 (SE) mmHg−1] ( n = 9). The results of the study show that these models can be applied to the Sprague-Dawley rat data and, specifically, can be used to differentiate between the hypoxic and the control groups.
Current Flow in Vibrissa Motor Cortex Can Phase-Lock With Exploratory Rhythmic Whisking in Rat
Authors: Ahrens Kurt F. , Kleinfeld David
Published: August 2004

Rats explore their environment with rhythmic sweeps of their mystacial vibrissae in the range of 5–15 Hz. We tested if vibrissa primary motor (M1) cortex produces electrical activity that locks to this behavioral output. Rats were trained to whisk in air in search of a food reward. The EMG of the mystacial pad served as a surrogate of vibrissa position, while chronically implanted, 16-channel Si-based probes provided a record of field potentials throughout the depth of vibrissa M1 cortex as well as vibrissa primary somatosensory (S1) cortex. The measured potentials were used to estimate the current source density along the radial axis. We observed that current flow throughout the depth of M1 cortex is coherent with the mystacial EMG, i.e., the two signals co-vary with a defined phase relation. This coherence persists after transection of the infraorbital branch (IoN) of the trigeminal nerve, which provides the sole sensory input from the vibrissae. Furthermore, current flow in vibrissa S1 cortex that is coherent with the mystacial EMG also persists after transection of the IoN, consistent with anatomical pathways between M1 and S1. In combination with a previous observation that rhythmic, intracortical microstimulation of vibrissa M1 cortex can drive normal whisking motion, the present data support the hypothesis that, in principle, M1 cortex can initiate motion of the vibrissae on a cycle-by-cycle basis.
Glutamate Neurotransmission in the Cerebellar Interposed Nuclei: Involvement in Classically Conditioned Eyeblinks and Neuronal Activity
Authors: Aksenov D. P. , Serdyukova N. A. , Bloedel J. R. , Bracha V.
Published: August 2004

The cerebellar interposed nuclei (IN) are critical components of a neural network that controls the expression of classically conditioned eyeblinks. The IN receive 2 major inputs: the massive, γ-aminobutyric acid (GABA)–mediated input from the Purkinje cells of the cerebellar cortex and the relatively weaker, glutamate-mediated input from collaterals of mossy and climbing fiber cerebellar afferent systems. To elucidate the role of IN glutamate neurotransmission in conditioned response (CR) expression, effects of blocking fast glutamatergic neurotransmission in the IN with γ-d-glutamylglycine (DGG) on the expression of conditioned eyeblinks and on cerebellar nuclear neuronal activity were examined. Surprisingly, blocking fast glutamate receptors in the IN did not abolish CRs. DGG decreased CR incidence and slightly increased CR latency. In contrast, identical amounts of DGG applied to the cerebellar cortex abolished CRs. Similar to the behavioral effects, DGG had unexpectedly mild effects on IN neurons. At the population level, the baseline firing frequency of IN cells was not affected. After DGG injections, the incidence of excitatory modulation of cell activity in the interstimulus interval decreased but was not abolished. A combined block of fast glutamate and GABAA neurotransmission using a mixture of DGG and picrotoxin dramatically reduced CR incidence, increased the firing frequency of all cell types, and virtually abolished all modulation of neuronal activity. These results indicate that fast glutamate neurotransmission in the IN plays only an accessory role both in the expression of behavioral CRs and in the generation of associated neuronal activity in the IN.
Reticulospinal Neurons Receive Direct Spinobulbar Inputs During Locomotor Activity in Lamprey
Authors: Einum James F. , Buchanan James T.
Published: August 2004

Reticulospinal neurons of the lamprey brain stem receive rhythmic input from the spinal cord during locomotor activity. The goal of the present study was to determine whether such spinal input has a direct component to reticulospinal neurons or depends on brain stem interneurons. To answer this question, an in vitro lamprey brain stem-spinal cord preparation was used with a diffusion barrier placed caudal to the obex, separating the experimental chamber into two baths. Locomotor activity was induced in the spinal cord by perfusion of d-glutamate or N-methyl-dl-aspartate into the spinal cord bath. The brain stem bath was first perfused with normal Ringer solution followed by a high-Ca2+, -Mg2+ solution, which reduced polysynaptic transmission. The amplitudes of membrane potential oscillations of reticulospinal neurons in the posterior and middle rhombencephalic reticular nuclei (PRRN and MRRN, respectively) recorded with sharp intracellular microelectrodes did not significantly change from normal to high-divalent solution. This finding suggests a large part of the spinal input creating the oscillations is direct to the reticulospinal neurons. Application of strychnine to the high-Ca2+, -Mg2+ solution decreased membrane potential oscillation amplitude, and injection of Cl− reversed presumed inhibitory postsynaptic potentials, indicating a role for direct spinal inhibitory inputs. Although reduced, the persistence of oscillations in strychnine suggests that spinal excitatory inputs also contribute to the oscillations. Thus it was concluded that both excitatory and inhibitory spinal neurons provide direct rhythmic inputs to reticulospinal cells of the PRRN and MRRN during locomotor activity. These inputs provide reticulospinal cells with information regarding the activity of the spinal locomotor networks.
The class of functions spirallike with respect to a boundary point
Authors: Lecko Adam
Published: August 2004

The aim of this paper is to present an analytic characterization of the class of functions δ‐spirallike with respect to a boundary point. The method of proof is based on Julia′s lemma.
Double Visualization Using Triamcinolone Acetonide and Trypan Blue during Stage 3 Macular Hole Surgery
Authors: Yamamoto Narumichi , Ozaki Noriko , Murakami Kimio
Published: August 2004

Purpose: To study the usefulness of intravitreal injection of triamcinolone acetonide and trypan blue for facilitating visualization and dissection of the posterior vitreous cortex and internal limiting membrane (ILM) during vitrectomy in idiopathic stage 3 macular holes. Methods: Pars plana vitrectomy was performed in 10 eyes of 10 patientswith idiopathic stage 3 macular holes. After core vitrectomy had been performed, triamcinolone acetonide was injected over the posterior pole. After separation of the visualized posterior vitreous cortex, trypan blue was injected over the macular area. Excised specimens were examined by electron microscopy. Results: Upon injection of triamcinolone acetonide, the posterior vitreous cortex and residual vitreous cortex could be visualized in all patients. The posterior vitreous cortex and residual vitreous cortex were completely removed. The ILM of the retina was stained faint blue and was successfully removed in all patients. Electron microscopy revealed that the triamcinolone-acetonide-visualized layer and the trypan-blue-stained layer had different histological features. No complications related to the use of triamcinolone acetonide and trypan blue were encountered. Conclusion: Double visualization of the posterior vitreous cortex and ILM using triamcinolone acetonide and trypan blue during vitrectomy may facilitate separation of the posterior vitreous cortex from the retina and removal of the ILM around the macular hole in patients withidiopathic stage 3 macular holes.
Age-Related Modifications of Corneal Sensitivity
Authors: Roszkowska Anna M. , Colosi Pietro , Ferreri Felicia M.B. , Galasso Santo
Published: August 2004

Purpose: To evaluate central and peripheral corneal sensitivity (CS) in relation to age. Methods: Five hundred eyes of 320 healthy subjects (185 males and 135 females) were examined. The age of participants ranged from 20 to 90 years. All subjects were divided into 3 groups according to age. CS was assessed with the Cochet-Bonnet esthesiometer in the central cornea and in 8 peripheral points. The averages were used as the values of central and peripheral CS. Results: In the young population, CS was equal in both examined zones (p > 0.05); although, with respect to the periphery after the fifth decade, it was significantly higher in the centre (p < 0.05). Both central and peripheral sensitivity decreased with age (p < 0.05), and such variations are represented by parabolic curves. No differences were observed between males and females. Conclusions: The age-related decrement of CS involves at first the corneal periphery and successively spreads toward the central zone. Topographical distribution and age-related modifications should be considered in clinical investigations of CS, especially in patients who underwent any corneal surgical procedure.
Effects of Preservatives in Nasal Formulations on the Mucosal Integrity: An Electron Microscopic Study
Authors: Lebe Erkan , Baka Meral , Yavaşoğlu Altuğ , Aktuğ Hüseyin , Ateş Utku , Uyanıkgil Yiğit
Published: August 2004

The preservatives benzalkonium chloride (BZC) and potassium sorbate (PS) are widely used in the formulation of nasal drops and cosmetics. Recently, a number of side effects that resulted from mucosal irritation caused by BZC and PS have been reported. Therefore, this study was performed to investigate the possible clinical and histological alterations induced by in vivo administration of these preservatives to the nasal mucosa of rats. 0.01% BZC and 0.12% PS were administered to the nostrils of male rats for 1 or 4 weeks. Clinical symptoms were recorded during the treatment, and light and electron microscopic examinations were carried out on samples taken from one third central and lower regions of the noses at the end of the treatment periods. Symptomatic changes such as sneezing and nasal rubbing were observed in almost all groups, starting from the 6th day of administration. Light and electron microscopy showed histological changes and nasal lesions induced by the preservatives. The symptomatic and histological changes were more pronounced with prolonged duration of administration. Therefore, it has been concluded that in vivo administration of the preservatives BZC and PS may be irritant to the respiratory epithelium of rats.
Relaxant Effects of Estradiol through Non-Genomic Pathways in Male and Female Pig Bladder Smooth Muscle
Authors: Dambros Miriam , van Koeveringe Gommert A. , Bast Aalt , van Kerrebroeck Philip E.V.
Published: August 2004

The precise effect of low estrogen levels on urinary bladder contractility remains controversial. The present study was designed to analyze the effect of 17β-estradiol in bladder smooth muscle contractility and the involvement of specific estrogen receptor stimulation in this effect. Castrated male and female pig detrusor strips were mounted for tension recording in an organ bath, superfused with Krebs solution at 37°C and stimulated electrically and pharmacologically. In order to verify the acute effect of 17β-estradiol on muscle contractility, the strips were incubated with different concentrations of the hormone. Muscle contractions were induced by potassium chloride, acetylcholine chloride and electrical field stimulation. The involvement of the estrogen receptor in the effects of 17β-estradiol was assessed by incubation of some strips with the selective estrogen receptor antagonist ICI 182.780 before estradiol was applied. Estradiol at a dose of 30 µmol/l elicited a lower amplitude of contractions induced by EFS, Ach and KCl in female as well as in castrated male pig bladder smooth muscle strips. The effects of 17β-estradiol were stronger in contractions induced by potassium chloride than those induced by other forms of stimulation. Pre-treatment with the pure estrogen receptor antagonist had no effect on 17β-estradiol-induced inhibition of muscle contractility. These observations suggest that 17β-estradiol induces lower amplitude of contraction of female as well as castrated male pig detrusor which is not mediated by the classic estrogen receptor. Furthermore, we can conclude that estradiol has a stronger inhibitory effect on the depolarization of muscle cell membrane compared to a muscarinic receptor-induced contraction.
Ethanol-Induced Changes in Lipid Composition of Intestinal Microvillus Membrane in Rats Fed Different Dietary Fats
Authors: Kaur Meenu , Kaur Jyotdeep , Gupta Reena , Ojha Sudarshan , Mahmood Akhtar
Published: August 2004

Background/Method: The effect of feeding ethanol for 5 weeks on the lipid composition of the intestinal microvillus membrane (MVM) was studied in rats fed a commercial rat pellet (RP) diet or purified diets containing 10% coconut oil (CCO), corn oil (CO) or fish oil (FO). Results: A low cholesterol/phospholipid ratio and increased saturated fatty acid level were observed in MVM from the CCO or FO groups. Chronic administration of ethanol to RP- or CO-fed animals increased phospholipids, total and free cholesterol, and the triglyceride and ganglioside content of MVM. The free cholesterol and phospholipid content was reduced while the triglyceride level remained unaffected by ethanol treatment in the CCO or FO groups. Ethanol ingestion decreased 10:2 and 20:4 (n–6 fatty acids) but increased the saturated fatty acid content of MVM in all the dietary groups except in CCO-fed animals where the 18:2 level was not affected. An elevated 18:1, but decreased 22:6 percentage was observed in the ethanol-fed FO group. The fatty acid composition of MVM from the CCO-fed group was least affected by ethanol treatment. Conclusion: These observations suggest that the type of dietary fat modifies ethanol-mediated alterations in MVM lipid composition.
Is AV Fistula Patency Associated with Angiotensin-Converting Enzyme (ACE) Polymorphism and ACE Inhibitor Intake?
Authors: Heine Gunnar H. , Ulrich Christof , Köhler Hans , Girndt Matthias
Published: August 2004

Background/Aims: Hemodialysis treatment requires a well-functioning vascular access. Access patency is limited by the development of venous intimal hyperplasia, which predisposes to fistula stenosis and subsequent thrombosis. In animal models, the renin-angiotensin system has a major role in the development of intimal hyperplasia. We investigated the association of the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) and arteriovenous fistula patency in hemodialysis patients. Methods: In a longitudinal study, 137 hemodialysis patients who had undergone creation of a primary AV fistula were genotyped. The main study endpoint was unassisted access patency (time from fistula placement to the first episode of access failure). In addition, the intake of drugs blocking the renin-angiotensin system was assessed. Results: Fistula patency 12 months after fistula creation was 72% (DD patients), 65% (ID patients), and 73% (II patients; p = 0.40). Long-term intake of ACE inhibitors or AT-1 antagonists failed to increase fistula patency (p = 0.33). Conclusions: We suggest that pharmacological inhibition of the renin-angiotensin system is of limited value for prevention of arteriovenous fistula stenosis. Alternative strategies to prolong fistula patency should be studied.
Low-Density Lipoprotein Particle Size Loci in Familial Combined Hyperlipidemia
Authors: Badzioch Michael D. , Igo Robert P. , Gagnon France , Brunzell John D. , Krauss Ronald M. , Motulsky Arno G. , Wijsman Ellen M. , Jarvik Gail P.
Published: August 2004

Objective—Low-density lipoprotein (LDL) size is associated with vascular disease and with familial combined hyperlipidemia (FCHL).

Methods and Results—We used logarithm of odds (lod) score and Bayesian Markov chain Monte Carlo (MCMC) linkage analysis methods to perform a 10-cM genome scan of LDL size, measured as peak particle diameter (PPD) and adjusted for age, sex, body mass index, and triglycerides in 4 large families with FCHL (n=185). We identified significant evidence of linkage to a chromosome 9p locus (multipoint lodmax=3.70; MCMC intensity ratio [IR]=21) in a single family, and across all 4 families to chromosomes 16q23 (lodmax=3.00; IR=43) near cholesteryl ester transfer protein (CETP) and to 11q22 (lodmax=3.71; IR=120). Chromosome 14q24-31, a region with previous suggestive LDL PPD linkage evidence, yielded an IR of 71 but an lodmax=1.79 in the combined families.

Conclusions—These results of significant evidence of linkage to 3 regions (9p, 16q, and 11q) and confirmatory support of previous reported linkage to 14q in large FCHL pedigrees demonstrate that LDL size is a trait influenced by multiple loci and illustrate the complementary use of lod score and MCMC methods in analysis of a complex trait.
Platelet GP IIIa Polymorphism HPA-1 (PlA) Protects Against Subarachnoid Hemorrhage
Authors: Iniesta Juan A. , González-Conejero Rocio , Piqueras Claudio , Vicente Vicente , Corral Javier
Published: August 2004

Background and Purpose—

Few genetic modifications have been identified to be associated with subarachnoid hemorrhage (SAH), most of them playing a role in the formation or size of aneurysms.

Methods—

We evaluated the role of common and functional polymorphisms affecting the main platelet adhesive glycoproteins (GP) (GPIIIa: HPA-1; GPIa: HPA-5 and C807T; GPIbα: HPA-2 and VNTR) in the risk for development of the disease and in the severity of the onset. The study was performed in 103 patients with SAH, 103 matched controls, and 473 subjects from the general population.

Results—

The HPA-1b (PlA2) allele significantly protected against SAH (OR, 0.48; 95% CI, 0.24 to 0.96;
P
=0.037). Interestingly, patients carrying this allele displayed larger aneurysms, but the extension of their hemorrhage and the clinical grade at presentation was significantly lower when compared with patients HPA-1 a/a (11.9±2.8 mm versus 8.8±2.2 mm,
P
=0.0001. Fisher grade ≤2: 68.4% versus 20%;
P
=0.0001; Hunt and Hess score <IV; 84.2% versus 53.8%;
P
=0.0187, respectively). The protection of the HPA-1b allele seemed to be exacerbated by the simultaneous presence of the HPA-2b allele. Thus, no patient carried this combination, which was present in 7.8% of controls (
P
=0.007).

Conclusions—

We present the first evidence suggesting a protective role for the platelet GPIIIa HPA-1b allele in SAH. The suggested platelet hyper-reactivity determined by this allele could reduce the risk to suffer SAH, specially if the aneurysm is small, attenuate the severity of the hemorrhage, and reduce the clinical grade at presentation. This effect might be amplified by the simultaneous combination with the GPIbα HPA-2b allele.
Automatic Generation of Controllers for Embodied Legged Organisms: A Pareto Evolutionary Multi-Objective Approach
Authors: Teo Jason , Abbass Hussein A.
Published: August 2004

In this paper, we investigate the use of a self-adaptive Pareto evolutionary multi-objective optimization (EMO) approach for evolving the controllers of virtual embodied organisms. The objective of this paper is to demonstrate the trade-off between quality of solutions and computational cost. We show empirically that evolving controllers using the proposed algorithm incurs significantly less computational cost when compared to a self-adaptive weighted sum EMO algorithm, a self-adaptive single-objective evolutionary algorithm (EA) and a hand-tuned Pareto EMO algorithm. The main contribution of the self-adaptive Pareto EMO approach is its ability to produce sufficiently good controllers with different locomotion capabilities in a single run, thereby reducing the evolutionary computational cost and allowing the designer to explore the space of good solutions simultaneously. Our results also show that self-adaptation was found to be highly beneficial in reducing redundancy when compared against the other algorithms. Moreover, it was also shown that genetic diversity was being maintained naturally by virtue of the system's inherent multi-objectivity.
Insulin-Induced Cell Cycle Progression Is Impaired in Chinese Hamster Ovary Cells Overexpressing Insulin Receptor Substrate-3
Authors: Kaburagi Yasushi , Yamashita Ryo , Ito Yuzuru , Okochi Hitoshi , Yamamoto-Honda Ritsuko , Yasuda Kazuki , Sekihara Hisahiko , Sasazuki Takehiko , Kadowaki Takashi , Yazaki Yoshio
Published: August 2004

To analyze the roles of insulin receptor substrate (IRS) proteins in insulin-stimulated cell cycle progression, we examined the functions of rat IRS-1 and IRS-3 in Chinese hamster ovary cells overexpressing the human insulin receptor. In this type of cell overexpressing IRS-1 or IRS-3, we showed that: 1) overexpression of IRS-3, but not IRS-1, suppressed the G1/S transition induced by insulin; 2) IRS-3 was more preferentially localized to the nucleus than IRS-1; 3) phosphorylation of glycogen synthase kinase 3 and MAPK/ERK was unaffected by IRS-3 overexpression, whereas that of protein kinase B was enhanced by either IRS; 4) overexpressed IRS-3 suppressed cyclin D1 expression in response to insulin; 5) among the signaling molecules regulating cyclin D1 expression, activation of the small G protein Ral was unchanged, whereas insulin-induced gene expression of c-myc, a critical component for growth control and cell cycle progression, was suppressed by overexpressed IRS-3; and 6) insulin-induced expression of p21, a cyclin-dependent kinase inhibitor, was decreased by overexpressed IRS-3. These findings imply that: 1) IRS-3 may play a unique role in mitogenesis by inhibiting insulin-stimulated cell cycle progression via a decrease in cyclin D1 and p21 expressions as well as suppression of c-myc mRNA induction in a manner independent of the activation of MAPK, protein kinase B, glycogen synthase kinase 3 and Ral; and 2) the interaction of IRS-3 with nuclear proteins may be involved in this process.
“Hijacking” the Thyrotropin Receptor: A Chimeric Receptor-Lysosome Associated Membrane Protein Enhances Deoxyribonucleic Acid Vaccination and Induces Graves’ Hyperthyroidism
Authors: Pichurin Pavel N. , Chazenbalk Gregorio D. , Aliesky Holly , Pichurina Oxana , Rapoport Basil , McLachlan Sandra M.
Published: August 2004

Naked DNA vaccination with the TSH receptor (TSHR) does not, in most studies, induce TSHR antibodies and never induces hyperthyroidism in BALB/c mice. Proteins expressed endogenously by vaccination are preferentially presented by major histocompatibility complex class I, but optimal T cell help for antibody production requires lysosomal processing and major histocompatibility complex class II presentation. To divert protein expression to lysosomes, we constructed a plasmid with the TSHR ectodomain spliced between the signal peptide and transmembrane-intracellular region of lysosome-associated membrane protein (LAMP)-1, a lysosome-associated membrane protein. BALB/c mice pretreated with cardiotoxin were primed intramuscularly using this LAMP-TSHR chimera and boosted twice with DNA encoding wild-type TSHR, TSHR A-subunit, or LAMP-TSHR. With each protocol, spleen cells responded to TSHR antigen by secreting interferon-γ, and 60% or more mice had TSHR antibodies detectable by ELISA. TSH binding inhibitory activity was present in seven, four, and two of 10 mice boosted with TSHR A-subunit, LAMP-TSHR, or wild-type TSHR, respectively. Importantly, six of 30 mice had elevated T4 levels and goiter (5 of 6 with detectable thyroid-stimulating antibodies). Injecting LAMP-TSHR intradermally without cardiotoxin pretreatment induced TSHR antibodies detectable by ELISA but not by TSH binding inhibitory activity, and none became hyperthyroid. These findings are consistent with a role for cardiotoxin-recruited macrophages in which (unlike in fibroblasts) LAMP-TSHR can be expressed intracellularly and on the cell surface. In conclusion, hijacking the TSHR to lysosomes enhances T cell responses and TSHR antibody generation and induces Graves’-like hyperthyroidism in BALB/c mice by intramuscular naked DNA vaccination.