{Background. Two common techniques of bilateral internal thoracic artery grafting are the composite T graft and in situ crossover graft. The superiority of one method over the other has not yet been established. Methods. From April 1996 to July 1999, bilateral skeletonized internal thoracic arteries were used as T grafts (composite group
Development and differentiation of the vertebrate caudal midbrain and anterior hindbrain are dependent on the isthmic organizer signals at the midbrain/hindbrain boundary (MHB). The future MHB forms at the boundary between the Otx2 and Gbx2 expression domains. Recent studies in mice and chick suggested that the apposition of Otx2- and Gbx2-expressing cells is instrumental for the positioning and early induction of the MHB genetic cascade. We show that Otx2 and Gbx2 perform different roles in this process. We find that ectopically expressed Otx2 on its own can induce a substantial part of the MHB genetic network, namely En2, Wnt1, Pax-2, Fgf8 and Gbx2, in a concentration-dependent manner. This induction does not require protein synthesis and ends during neurulation. In contrast, Gbx2 is a negative regulator of Otx2 and the MHB genes. Based on the temporal patterns of expression of the genes involved, we propose that Otx2 might be the early inducer of the isthmic organizer genetic network while Gbx2 restricts Otx2 expression along the anterior-posterior axis and establishes an Otx2 gradient.
A unilateral external skeletal fixator (ESF) system with an acrylic connecting bar, combined with an intramedullary OX pin, was used to treat simple, comminuted and open fractures of the tibia in 12 clinical cases occurring in large and small dogs, and in cats. A minimal surgical approach was used in all cases, The I.M pin was placed first, in the normograde fashion, to align the tibial fragments, Transfixation pins were then inserted from the medial side, using previously published guidelines for safe corridors in the tibia (30), thus minimizing the potential for soft tissue trauma. An acrylic connecting bar was used in all of the cases, enabling connection of pins that were not in the some plane. All of the fractures healed uneventfully. This report shows that unilateral ESF with an acrylic connecting bar, combined with an I.M pin, is an effective method for the repair of a wide variety of tibial fractures.
Paraneoplastic syndromes associated with lung cancer are diverse in their presentation, pathophysiology, and implications. They can be seen as a diagnostic and therapeutic challenge or as an opportunity to detect an otherwise asymptomatic malignancy. Unraveling the mechanisms that produce these syndromes will lead to insight into tumor biology that will be translated into novel approaches for early detection and therapy.
Linear polymers of lysine and arginine, phagocyte-derived lysozyme, PLA, elas- tase, cathepsin G, myeloperoxidases, nu- clear histone and bacterial/permeability-en- hancing peptide (BPI) and defensins all possess bactericidal activities [1, 2, 3, 4, 5, 6]. The highly cationic BPI and defensins might kill Gram-negatives primarily by de- polarizing their outer membrane to en- hance its permeability [3]. However, it had also been proposed that many of these polycations might also function as “Trojan Horses” to disrupt the intracellular regula- tion of the autolytic wall enzyme systems (muramidases).This can lead to cleavage of the peptidoglycan, to bacteriolysis, and to cell death [4, 5, 6].The highly cationic, ly- sozyme, PLA2, and elastase probably do not function solely as enzymes, but rather as highly cationic agents. The bactericidal and bacteriolytic effects of polycations might therefore mimic the bacteriolytic ef- fects caused by beta-lactam antibiotics. Sulfated compounds (heparin, dextran sul- fate, polyaenthole sulfonate) very efficient-
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ly inhibited the activation of bacterial au- tolysis induced either by cationic agents or by beta-lactam antibiotics [4, 5, 6, 7]. Therefore, it is highly likely that polycat- ions of plasma and leukocyte origins might be actively involved in the pathophysiolo- gy of post-infectious sequelae by their ca- pacity to induce a massive release of high- ly phlogistic lipoteichoic acid [7] endotox- in, lipoprotein, and peptidoglycan [8].
Combinations among these agents might act on mononuclear cells to generate reactive oxygen species, NO, NOO-, hy- drolases, and also to activate the coagula- tion, complement, and cytokine cascades, all involved in septic shock. Based on the above arguments, it is tempting to specu- late that the failure to depress early bacteri- olysis in the bloodstream might be the main cause for the inability to cope with the multiple synergistic interactions lead- ing to post-infectious sequelae [9]. The clinical use of polyanions when combined with mutli drug strategies might therefore be recommended as potent anti-bacteriolyt- ic and anti-inflammatory agents [10]. It is enigmatic why publications that have pro- posed the role of polycations in bacterioly- sis and the possibility to inhibit its unto- ward effects by polyanions, findings so rel- evant to the patholysiology of post-infec- tious sequelae, are consistently disregarded [11] either in basic science publications on the bactericidal effects of polycations or in the clinical literature dealing with post-in- fectious sequelae.
Tzachi Zamir. 2002. “Phaedo's Hair.” Iyyun: The Jerusalem Philosophical Quarterly, 51, Pp. 139-154. Abstract
This paper investigates the complicated status of critical thought and its suspension in Plato's 'Phaedo'. The philosophical "heart" of this dialogue lies not in the arguments over the immortality of the soul, but rather in the discrepancy between these and the dramatic occurrences and what this implies. Plato uses Socrates to both embody the ideal of critical reflection and philosophical searching, and at the same time to exhibit moments wherein reflection has to give way to suasion and allowing oneself to be "magically charmed". Withdrawing from a critical attitude is articulated both by Cebes and Siminias who are the sharpest and most critical of Socrates' interlocutors at the dialogue. But the same "misosophic" movement may also be perceived by Socrates. This makes for a fascinating metaphilosophical vision in which philosophy cannot be equated with argumentative, rigorous thought. Underlying this theme is another one, in which Socrates' general detachment from his own body and the body of others is momentarily replaced by a connection with a beautiful part of another's body: Phaedo's hair. Avoiding a critical attitude intertwines with this abrupt emergence of bodily contact, creating a retreat from a certain vision of philosophical life that we usually identify with Socrates.
The optimal conditions under which hypochlorous acid (NaOCl) either hemolyzes human RBC or kills monkey kidney epithelial cells (BGM) in culture had been investigated. While in Hank's balanced salt solution (HBSS), micromolar amounts of NaOCl caused full hemolysis and also killed BGM cells, in D-MEM or RPMI media rich in amino acids, 25-40 mM of hypochlorite were needed to induce cell injury. Cells exposed to high amounts of NaOCl became highly refractory to strong detergents. Hemolysis by NaOCl was strongly inhibited by a large variety of antioxidants. RBC treated by subtoxic concentrations either of peroxide, peroxyl radical, NO, cholesterol, PLA2, PLC as well as by N2, argon or by mixture of CO2 (10%) and O2 (90%) became much more susceptible to lysis by NaOCl. On the other hand, while RBC treated by Fe2+, Co2+, and V2+ and to a lesser extent with Cu2+ became highly resistant to NaOCl hemolysis presumably due to NaOCl decomposition, no such effect was found either with Co2+ or by Mn2+. RBC treated by azide to destroy catalase and then incubated with peroxide and with NaOCl failed to undergo hemolysis due to the ability of peroxide to decompose NaOCl. The inhibitory effects of the divalent metals on NaOCl-induced hemolysis were also substantiated by measuring the decrease in pH and by cyclic voltammetry. The findings that like peroxide, NaOCl also synergizes with membrane-perforating agents and with a protease to kill epithelial cells further implicate such "cocktails" in cell injury in inflammatory conditions. Taken together, because of the capacity of many agents to scavenge NaOCl, tissue damage by NaOCl-generated neutrophils can take place primarily if activated neutrophils closely adhere to target cells to avoid the scavenging effects of amino acids and of antioxidants. Therefore, the significance of the data which had tested the cytotoxic effects of NaOCl using cells suspended only in salt solutions, should be reconsidered.
Photoejection of electrons from 2,5,8,11-tetra-tert-butylcycloocta[1,2,3,4-def;5,6,7,8-d'e'f']bisbiphe nylene radical anion, BPD.-, and the respective dianion, BPD2-, are described. Photoejection of an electron from BPD2- yields a [BPD.-...e(-)] cage complex and separated BPD.- and e(-)/Li+ species. Recombination of the cage photoproducts proceeds at room temperature with a rate constant of k(rec)(1) = (7.0 +/- 0.2) x 10(5) s(-1), and the separated photoproducts recombine by a diffusional back-electron-transfer rate constant of k(rec)(2) = (1.5 +/- 0.2) x 10(9). M-1.s(-1). Photoejection of the electron from BPD.- yields the neutral pi-system, BPD, and the ejected electron reduces an unreacted BPD.- to form BPD2-. The photoejection of the electron from BPD.- thus yields the disproportionation products, BPD and BPD2-. The disproportionation products recombine by a diffusional process, k(rec) = (1.0 +/- 0.2) x 10(10) M-1.s(-1) (at room temperature).
We have found that photoinduced pyridine ring cleavage-closure occurs in polymeric viscous solution, because in certain polymer solutions, pyridine can serve as a photo-modulated crosslinker. We suggest this reaction as a way to control a polymer's optical properties. Irradiation of the system: poly(4-vinyl pyridine)/pyridine/water with 250-nm wavelength range leads to the appearance of a new absorption band centered at 360 nm, new red-shifted emission, and HOMO-LUMO band gap changes. The subsequent irradiation with 360 nm (the new absorption band maximum) leads to reversion almost to the initial stage. A main active product of the photoreaction is aldehyde enamine, which has two active groups: primary amine and aldehyde, which can associate with the polymer molecules to form a physical crosslinked supramolecular structure. We evaluated the activation energy of the pyridine ring cleavage and back reaction depending on the polymer/pyridine/water ratio and by changing the polymer structure. The activation energy of pyridine's ring cleavage in viscous polymeric solutions is in the range of 0.6–3.2 Kcal/mol. The activation energy of the back reaction is significantly lower and is in the range of 0.05–0.15Kcal/mole.
Electroholography is a wavelength-selective optical switching method based on governing of the reconstruction process of volume holograms by means of an electric field. Electroholography is based on the voltage-controlled photorefractive effect in the paraelectric phase. The basic switching device is an electrically controlled Bragg grating or a volume hologram stored in a volume of a paraelectric crystal by the photorefractive process.
The basic electroholographic switching operation is the reconstruction of a volume grating (hologram), which requires that the Bragg condition be satisfied, and therefore is wavelength selective. In addition the applied field governs the efficiency of the reconstruction. Consequently, electroholographic switching includes grouping, multicasting, power management and non-intrusive data as an integral part of the switching operation. In preliminary measurements the performance envelope of the electroholography-based switch, is a cube of 1.8 mm3 was found to be as follows:
The minimum net insertion loss is 0.5 dB per switching operation. The minimum loss when a beam propagates through a latent grating is 0.2%. The Polarization-Dependent Loss (PDL) in a device that includes diversity architecture is less than 0.4 dB and the Polarization Mode Dispersion (PMD) is less than 0.07 ps. Bit-error rate (BER) in a switch operating at 40 Gb/s was measured to be 10-13. These features make electroholography ideal for circuit switching applications. Finally, response times of approximately 10 ns were measured, opening the way to burst switching applications.
It is shown that doping the highly polarizable KTaO3 perovskite simultaneously by Li and Nb (K1−xLixTa1−yNbyO3, KLTN) gives rise to new impressive dipole ordering effects, very unusual physical properties and strong responses with respect to doping parameters. Besides, KLTN has outstanding perspectives of application in electrically controlled holographic and compositionally graded pyroelectric devices.
The dielectric and ferroelectric properties of K1-xLixTa1-yNbyO3 (KLTN) crystals as functions of temperature, frequency, and electric field are presented. Measurement of the polarization as a function of temperature indicates the existence of polarized microregions at temperatures well above the phase transition (PT) temperature. In the vicinity of the PT those microregions respond cooperatively and contribute to the observed macroscopic polarization. This cooperative behavior was also evident from dielectric relaxation measurements. Two relaxation processes were observed, one at high frequency and the other at low frequency. In both processes the relaxation time and the relaxation step (DeltaE) were found to increase as the PT temperature was approached. Those processes originate from movement of off-center ions in a multi-well potential. In the vicinity of the PT the correlation length of the host lattice is increased and the movements of the off-center ions become more and more correlated. The increased number of cooperatively relaxing ions increases the relaxation time and the relaxation amplitude. (C) 2002 Published by Elsevier Science B.V.
Abraham Neyman. 2002. “Values of Games with Infinitely Many Players.” In Handbook of Game Theory, with Economic Applications, edited by Roberth J Aumann and sergiu hart, 3: Pp. 2121--2167. Amsterdam: North-Holland.
The literature dealing with the biochemical basis of bacteriolysis and its role in inflammation, infection and in post-infectious sequelae is reviewed and discussed. Bacteriolysis is an event that may occur when normal microbial multiplication is altered due to an uncontrolled activation of a series of autolytic cell-wall breaking enzymes (muramidases). While a low-level bacteriolysis sometimes occurs physiologically, due to "mistakes" in cell separation, a pronounced cell wall breakdown may occur following bacteriolysis induced either by beta-lactam antibiotics or by a large variety of bacteriolysis-inducing cationic peptides. These include spermine, spermidine, bactericidal peptides defensins, bacterial permeability increasing peptides from neutrophils, cationic proteins from eosinophils, lysozyme, myeloperoxidase, lactoferrin, the highly cationic proteinases elastase and cathepsins, PLA2, and certain synthetic polyamino acids. The cationic agents probably function by deregulating lipoteichoic acid (LTA) in Gram-positive bacteria and phospholipids in Gram-negative bacteria, the presumed regulators of the autolytic enzyme systems (muramidases). When bacteriolysis occurs in vivo, cell-wall- and -membrane-associated lipopolysaccharide (LPS (endotoxin)), lipoteichoic acid (LTA) and peptidoglycan (PPG), are released. These highly phlogistic agents can act on macrophages, either individually or in synergy, to induce the generation and release of reactive oxygen and nitrogen species, cytotoxic cytokines, hydrolases, proteinases, and also to activate the coagulation and complement cascades. All these agents and processes are involved in the pathophysiology of septic shock and multiple organ failure resulting from severe microbial infections. Bacteriolysis induced in in vitro models, either by polycations or by beta-lactams, could be effectively inhibited by sulfated polysaccharides, by D-amino acids as well as by certain anti-bacteriolytic antibiotics. However, within phagocytic cells in inflammatory sites, bacteriolysis tends to be strongly inhibited presumably due to the inactivation by oxidants and proteinases of the bacterial muramidases. This might results in a long persistence of non-biodegradable cell-wall components causing granulomatous inflammation. However, persistence of microbial cell walls in vivo may also boost innate immunity against infections and against tumor-cell proliferation. Therapeutic strategies to cope with the deleterious effects of bacteriolysis in vivo include combinations of autolysin inhibitors with combinations of certain anti-inflammatory agents. These might inhibit the synergistic tissue- and- organ-damaging "cross talks" which lead to septic shock and to additional post-infectious sequelae.
